Radiation Curing: State-of-the-Art Assessment

Radiation Curing: State-of-the-Art Assessment

Electric Power
Research lnst it Ute
Topics:
Radiation processing
Radiation-processing chemistry
End use
Technology assessment
Technology utilization
Electrotechnology
P=#EwS1
J7
EPRl EM-4570
Project 2613-3
Final ReDort
June 1986
!or-
Radiation Curing:
- State-of-the-Art
Assessment
Prepared by
Battelle Columbus Division
Columbus, Ohio
R E P O R T
SUBJECT
TOPICS
S U M M A R Y
Industrial electric technologies
Radiation processing
Radiation-processing chemistry
End use
Technology assessment
Technology utilization
Electrotechnology
'
~
AUDIENCE
Customer service engineers / Marketing managers
Radiation Curing: State-of-the-Art Assessment
Radiation curing of polymeric materials offers utilities an opportunity to promote efficient electricity-based processing among
their industrial customers. According to this assessment, manufacturing use of the technology is likely to grow from 10 to 20%
annually for the next 15 years.
BACKGROUND
EPRl EM-4570s
Radiation curing is an efficient and relatively low temperature electricitybased technology with many applications in coating, printing, adhesives,
electronics, and communication materials. Moreover, the application of electromagnetic radiation-from infrared, ultraviolet, high-energy electron,
microwave, or radio-frequency sources-can improve the overall physical or
chemical properties of polymeric materials to produce results that are
superior, in such characteristics as bonding, surface finish, and durability to
those of other technologies. Its speed and controllability in these applications, plus the narrowing gap between the costs of electricity and natural
gas, suggest an increasing market for this electrotechnology in manufacturing worldwide.
OBJECTIVE
To assess the state of the art of radiation-curing technologies as applied to
organic substrate materials.
APPROACH
After a review of the literature on all aspects of radiation-processing technologies, the project team interviewed U.S., European, and Japanese equipment manufacturers, material suppliers, and end users. Their analysis of
this information sought to characterize the major industries making wide
use of radiation curing, to clarify the developmental trends, and to evaluate
potential applications and market penetration, considering fuel prices and
competing technologies.
RESULTS
Radiation-processing technologies-widely accepted during the past 15
years in many new and varied industries-offer several major advantages
over other production methods. These benefits include rapid curing, low
process temperatures, the absence of pollution, and substantially lower
energy costs, as well as high-quality and specialized products. Typical product lines involve coatings (on wood, metal, paper, and plastic), inks (for
letterpress, lithographic, gravure, and screen printing), and adhesives
(for film, foil, or paper substrates). The industries using these technologies engage in such diverse activities as electronics, fiber optics, flooring, packaging, plastics, and plasma processing. Although radiation
curing is still a minor manufacturing technique, in future its industrial
use is expected to expand greatly-with an annual growth of 10 to 20%.
~
EPRl PERSPECTIVE
PROJECT
As electricity costs become more competitive with the costs of natural
gas for industrial processing, radiation curing has prospects of becoming a key area of growth for electricity-based process heating. Much of
that increased growth will come with the development of specialty
products or high-value-added products that can be made only by electromagnetic radiation derived from electricity.
RP2613-3
EPRl Project Manager: I. Leslie Harry
Energy Management and Utilization Division
Contractor: Battelle Columbus Division
For further information on EPRl research programs, call
EPRl Technical Information Specialists (415) 855-2411.
Radiation Curing: State-of-the-ArtAssessment
EM-4570
Research Project 2613-3
L
Final Report, June 1986
Prepared by
BATTELLE COLUMBUS DIVISION
505 King Avenue
Columbus, Ohio 43201
Principal Investigator
V. D. McGinniss
i
Prepared for
Electric Power Research Institute
3412 Hillview Avenue
Palo Alto, California 94304
EPRl Project Manager
I. L. Harry
Industrial Program
Energy Management and Utilization Division
ORDERING INFORMATION
Requests for copies of this report should be directed to Research Reports Center
(RRC), Box 50490, Palo Alto, CA 94303, (415) 965-4081. There is no charge for reports
requested by EPRl member utilities and affiliates, U.S. utility associations, US. government
agencies (federal, state, and local), media, and foreign organizations with which EPRl has
an information exchange agreement. On request, RRC will send a catalog of EPRl reports.
Electric Power Research Institute and EPRl are registered service marks of Electric Power Research Institute, Inc.
Copyright 0 1986 Electric Power Research Institute, Inc. All rights reserved
NOTICE
This report was prepared by the organization@) named below as an account of work sponsored by the Electric
Power Research Institute, Inc. (EPRI). Neither EPRI, members of EPRI, the organization(s) named below, nor any
person acting on behalf of any of them: (a) makes any warranty, express or implied, with respect to the use of any
information, apparatus, method, or process disclosed in this report or that such use may not infringe privately
owned rights; or (b) assumes any liabilities with respect to the use of, or for damages resulting from the use of,
any information, apparatus, method, or process disclosed in this report.
Prepared by
Battelle Columbus Division
Columbus, Ohio
ABSTRACT
I n t h e l a s t 15 years t h e c o n v e r s i o n o f e l e c t r i c a l energy i n t o i n f r a r e d , u l t r a v i o l e t
and h i g h energy e l e c t r o n e l e c t r o m a g n e t i c r a d i a t i o n has gained worldwide acceptance
as an e f f i c i e n t and economical method f o r m o d i f y i n g p o l y m e r i c m a t e r i a l s .
These
r a d i a t i o n m o d i f i e d polymer systems are a s s o c i a t e d w i t h many d i f f e r e n t types o f
p r o d u c t s which a r e produced under a wide d i v e r s i t y o f m a n u f a c t u r i n g o p e r a t i o n s .
T y p i c a l p r o d u c t l i n e o r a p p l i c a t i o n areas i n c l u d e :
c o a t i n g s (wood, m e t a l , paper-
packaging, f l o o r - f l e x i b l e p l a s t i c , w i r e , and t r a n s p o r t a t i o n c o a t i n g systems);
( l e t t e r p r e s s , l i t h o g r a p h y , flexography,
inks
g r a v u r e and screen p r i n t i n g ) ; adhesives
( p r e s s u r e s e n s i t i v e tapes and l a m i n a t i o n adhesives f o r f i l m , f o i l o r paper subs t r a t e s ) ; e l e c t r o n i c s ( i n t e g r a t e d c i r c u i t s , p r i n t e d c i r c u i t boards); communications
( f i b e r o p t i c s , magnetic and o p t i c a l media); p l a s t i c s and rubber m a t e r i a l s ( w i r e
and cable, p o l y o l e f i n s h r i n k wrap, p o l y o l e f i n foams); and plasma p r o c e s s i n g
(polymer s u r f a c e m o d i f i c a t i o n s and polymer c o a t i n g s ) .
The m a j o r advantages o f
r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s over o t h e r methods are:
r a p i d cu e, l o w
p r o c e s s i n g temperatures, s p e c i a l t y p r o d u c t s , h i g h q u a l i t y p r o d u c t s , no p o l l u t i o n
and s u b s t a n t i a l r e d u c t i o n i n energy c o s t s .
The t o t a l impact o f r a d a t i o n
p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s , w h i l e s i g n i f i c a n t , i s s t i l l o n l y a minor p a r t o f
t h e t o t a l p r o d u c t m a n u f a c t u r i n g techniques c u r r e n t l y i n use today.
However, t h e
f u t u r e use o f r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s i s expected t o expand
dramatically.
The o v e r a l l annual growth r a t e f o r r a d i a t i o n p r o c e s s i n g techniques
i s p r o j e c t e d t o be between 10 t o 20%, t h u s i t i s an a t t r a c t i v e area f o r f u t u r e
r e s e a r c h and development a c t i v i t y .
iii
ACKNOWLEDGMENTS
T h i s r e p o r t i s one o f a s e r i e s o f e l e c t r o t e c h n o l o g y assessments prepared
a t B a t t e l l e ' s Columbus D i v i s i o n i n c o o p e r a t i o n w i t h t h e E P R I Center f o r M e t a l s
Fabrication.
The o v e r a l l p r o j e c t has been conducted under t h e s u p e r v i s i o n o f
M r . Thomas G. B y r e r , D i r e c t o r o f t h e Center f o r Metals F a b r i c a t i o n .
Valuable
i n f o r m a t i o n f o r t h i s r e p o r t was a l s o p r o v i d e d by D r . Lee S e m i a t i n o f t h e Center f o r
M e t a l s F a b r i c a t i o n Department.
V
.
CONTENTS
Section
1
2
3
4
Page
.............................
RADIATION PROCESSING EQUIPMENT . . . . . . . . . . . . . . . . . . . .
Infrared Radiation Processing Equipment . . . . . . . . . . . . .
Ultraviolet (UV) Light Sources . . . . . . . . . . . . . . . . . .
High Energy Electron Radiation Processing Equipment . . . . . . .
Plasma Radiation Processing Equipment . . . . . . . . . . . . . .
RADIATION PROCESSING CHEMISTRY AND MATERIALS . . . . . . . . . . . . .
Thermal Radiation Processing Chemistry . . . . . . . . . . . . . .
UV-Visible Light Processing Chemistry . . . . . . . . . . . . . .
Free Radical Photocuring System . . . . . . . . . . . . . . .
Cationic Photocuring System . . . . . . . . . . . . . . . .
High Energy Electron Processing Chemistry . . . . . . . . . . . .
Thiol Curing Chemistry . . . . . . . . . . . . . . . . . . . . .
Plasma Processing Chemistry . . . . . . . . . . . . . . . . . . .
APPL ICATIONS/MARKETS . . . . . . . . . . . . . . . . . . . . . . . . .
Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wood Finishings . . . . . . . . . . . . . . . . . . . . . . .
Metal Decorative Coatings . . . . . . . . . . . . . . . . . .
Packaging Coatings . . . . . . . . . . . . . . . . . . . . .
Floor Coatings . . . . . . . . . . . . . . . . . . . . . . .
Wire Coatings . . . . . . . . . . . . . . . . . . . . . . . .
Transportation (Automotive) Coatings . . . . . . . . . . . .
Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Letterpress Process . . . . . . . . . . . . . . . . . . . . .
Lithography . . . . . . . . . . . . . . . . . . . . . . . . .
Flexography . . . . . . . . . . . . . . . . . . . . . . . . .
Gravure . . . . . . . . . . . . . . . . . . . . . . . . . . .
Screen Printing . . . . . . . . . . . . . . . . . . . . . . .
Radiation Curing Applications in Printing . . . . . . . . . .
Adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INTRODUCTION
vi i
1-1
2-1
2-1
2-6
2-15
2-32
3-1
3-1
3-5
3-5
3-7
3-8
3-10
3-11
4-1
4-2
4-5
4-6
4-13
4-18
4-18
4-22
4-22
4-26
4-26
4-26
4-30
4-31
4-31
4-35
Section
..................
Integrated C i r c u i t s ( I C ) . . . . . . . . . . . . . . . . . .
Lithography . . . . . . . . . . . . . . . . . . . . . . . . .
Adhesives and Encapsulants . . . . . . . . . . . . . . . . .
P r i n t e d C i r c u i t Boards . . . . . . . . . . . . . . . . . . .
F i b e r Optics . . . . . . . . . . . . . . . . . . . . . . . .
Magnetic and O p t i c a l Media . . . . . . . . . . . . . . . . . .
P l a s t i c s and Rubber M a t e r i a l s . . . . . . . . . . . . . . . . . .
Plasma Processing . . . . . . . . . . . . . . . . . . . . . . . .
COST AND ENERGY SAVINGS COMPARISONS . . . . . . . . . . . . . . . . . .
Cost Comparison .Radiation Processing Versus Thermal
Processing Technologies . . . . . . . . . . . . . . . . . . . . .
Coatings . . . . . . . . . . . . . . . . . . . . . . . . . .
P r i n t i n g Inks . . . . . . . . . . . . . . . . . . . . . . . .
Adhesives . . . . . . . . . . . . . . . . . . . . . . . . . .
Electronics/Communication . . . . . . . . . . . . . . . . . .
P l a s t i c and Rubber M a t e r i a l s . . . . . . . . . . . . . . . .
Plasma Processing . . . . . . . . . . . . . . . . . . . . . . . .
E l e c t r o n i c s and Communications
5
Impact o f Fuel Prices
6
......................
...................
Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wood F i n i s h i n g . . . . . . . . . . . . . . . . . . . . . . .
SALES HISTORY/MARKET PROJECTIONS
Metal Decorative Coatings
.................
.....................
Other Coating Systems . . . . . . . . . . . . . . . . . . . .
Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..
.........
a
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
APPENDIX
MANUFACTURERS OF RADIATION PROCESSING EQUIPMENT
AND MATERIAL SUPPLIERS . . . . . . . . . . . . . . . . . . . .
viii
4-48
4-55
4-59
4-59
4-62
4-66
4-74
5-1
5-1
5-2
5-6
5-10
5-10
5-16
5-19
5-19
6-1
6-1
6-4
6-8
6-14
..................
E l e c t r o n i c s and Communications . . . . . . . . . . . . . . . . .
R a d i a t i o n Processing Equipment . . . . . . . . . . . . . . . . . .
Competition From E x i s t i n g and Emerging Technologies . . . . . . .
CONCLUSIONS. FUTURE DEVELOPMENTS AND TECHNICAL V O I D S
4-48
6-12
P l a s t i c s and Rubber M a t e r i a l s
7
4-41
6-12
Packaging Coatings
Global Trends f o r Radiation Processing o f Polymeric M a t e r i a l s
Page
6-19
6-19
6-25
6-31
6-34
6-36
7-1
8-1
.
.
~~
A-1
.
ILLUSTRATIONS
Page
Figure
.......................
A p p l i c a t i o n o f Long Wave I R R a d i a t i o n . . . . . . . . . .
A p p l i c a t i o n o f Medium Wave I R R a d i a t i o n . . . . . . . . .
A p p l i c a t i o n o f S h o r t Wave I R R a d i a t i o n . . . . . . . . .
1-1
E l e c t r o m a g n e t i c Spectrum
1-2
2-1
Schematic o f
2-2
2-2
Schematic o f
2-3
Schematic o f
2-4
R e l a t i o n s h i p o f I R E m i t t e r Temperature t o Maximum I n t e n s i t y
Wavelength
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
2-16
2-17
2- 18
2-19
2-20
2-21
.............................
D i s t r i b u t i o n o f Wavelengths f r o m an I R E m i t t e r . . . . . . . . . . . .
I R Energy E f f i c i e n c y C o n s i d e r a t i o n s . . . . . . . . . . . . . . . . .
S e l e c t i v e A b s o r p t i o n o f I R R a d i a t i o n b y Various S u b s t r a t e s . . . . .
Common I R R a d i a t i o n E m i t t e r s .F u e l B u r n i n g Types . . . . . . . . . .
Common I R R a d i a t i o n E m i t t e r s .E l e c t r i c a l Types . . . . . . . . . . .
E l e c t r i c a l l y A c t i v a t e d Q u a r t z Tube I R E m i t t e r . . . . . . . . . . . .
UV/Vis L i g h t Source Power S u p p l i e s . . . . . . . . . . . . . . . . .
UV Lamp C o n f i g u r a t i o n s . . . . . . . . . . . . . . . . . . . . . . .
Commerci a1 UV Processor U n i t s . . . . . . . . . . . . . . . . . . . .
General Schematic o f A High Energy E l e c t r o n Beam Processing U n i t . . .
High and Low Energy E l e c t r o n Processor Power S u p p l i e s . . . . . . . .
Scanned E l e c t r o n Beam A c c e l e r a t o r System . . . . . . . . . . . . . . .
Energy Science P l a n a r Cathode E l e c t r o n C u r t a i n Processor . . . . . . .
Extended Processing Zone E l e c t r o n Beam Equipment . . . . . . . . . .
R a d i a t i o n Polymer C o r p o r a t i o n ' s Modular P l a n a r Cathode Processor . . .
H i s t o r i c a l Growth o f E l e c t r o n Beam A c c e l e r a t o r Systems . . . . . . . .
Comparison Between P l a n a r Cathode and Swept E l e c t r o n Beam
Processing U n i t s
..........................
ix
2-3
2-4
2-5
2-7
2-8
2-10
2-11
2-12
2-13
2-16
2-17
2-20
2-22
2-24
2-25
2-27
2-28
2-29
2-30
2-31
Figure
2-22
2-23
2-24
.
Page
..............
P a r a l l e l P l a t e E l e c t r o d e Plasma P o l y m e r i z a t i o n Apparatus . . . . . . .
A i r - t o - A i r Plasma Processing System . . . . . . . . . . . . . . . . .
2-35
Example o f Plasma Processing w i t h Supply and Take-up R o l l s
w i t h i n t h e Vacuum Chamber
2-36
Tubular Reactor f o r Plasma P o l y m e r i z a t i o n
2-33
2-34
i
2-25
3-1
4-1
......................
R a d i a t i o n Processing Chemistry . . . . . . . . . . . . . . . . . . .
Comparison between Conventional and R a d i a t i o n Curable C o a t i n g
Technologies
4-3
............................
R a d i a t i o n Curable Wood F i n i s h i n g Technology . . . . . . . . . . . . .
Wood F i n i s h i n g Operations . . . . . . . . . . . . . . . . . . . . . .
4-4
V a r n i s h i n g and UV C u r i n g l F i n i s h i n g L i n e f o r F l a t Stock Wood Products
4-2
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
.
.............
R a d i a t i o n Curable Can L i n e O p e r a t i o n . . . . . . . . . . . . . . . . .
Galvanized S t e e l Tubing L i n e . . . . . . . . . . . . . . . . . . . .
Cross S e c t i o n o f Tube L i n e Surrounded by Three o r Four UV Lamps . . .
R a d i a t i o n Curable F l o o r Sheet and F l o o r T i l e Product L i n e . . . . . .
T y p i c a l Wire C o a t i n g L i n e s . . . . . . . . . . . . . . . . . . . . . .
F i n i s h i n g L i n e f o r High-speed I R and UV Curable Coatings . . . . . . .
L e t t e r p r e s s Process . . . . . . . . . . . . . . . . . . . . . . . . .
L i t h o g r a p h y Process . . . . . . . . . . . . . . . . . . . . . . . . .
Flexography Process . . . . . . . . . . . . . . . . . . . . . . . . .
Gravure P r i n t i n g Process . . . . . . . . . . . . . . . . . . . . . .
E l e c t r o n Beam C u r i n g L i n e f o r Wood Products
.......................
O f f s e t Press Process w i t h UV Cure and EB Cure Processing U n i t s . . . .
Dryer C o n f i g u r a t i o n s . . . . . . . . . . . . . . . . . . . . . . . . .
Adhesive Market Area C l a s s i f i c a t i o n . . . . . . . . . . . . . . . . .
Adhesive F i l m Systems . . . . . . . . . . . . . . . . . . . . . . . .
Laminator Coater System . . . . . . . . . . . . . . . . . . . . . . .
Screen P r i n t i n g Process
X
3-2
4-4
4-7
4-8
4-9
4-11
4-14
4-15
4-16
4-20
4-21
4-24
4-27
4-28
4-29
4-32
4-33
4-36
4-37
4-39
4-43
4-44
Page
Figure
4-22
P r i n t e d W i r i n g C i r c u i t Board Showing D i v e r s e Uses o f P l a s t i c
Materials
4-24
..............................
I C M a n u f a c t u r i n g Process . . . . . . . . . . . . . . . . . . . . . . .
L i t h o g r a p h y Process . . . . . . . . . . . . . . . . . . . . . . . . .
4-25
Schematic o f Contact P r i n t i n g Using P o s i t i v e and N e g a t i v e R e s i s t s
4-23
4-26
4-27
4-28
4-29
4-30
4-31
4-32
4-33
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-10
6-11
6-12
6-13
4-47
4-49
4-51
..
...................
X- Ray L i t h o g r a p h y System . . . . . . . . . . . . . . . . . . . . . .
Automation o f S u r f ace-Mounted Boards . . . . . . . . . . . . . . . . .
UV C o a t i n g o f O p t i c a l F i b e r s . . . . . . . . . . . . . . . . . . . . .
Magnetic Media C o a t i n g L i n e w i t h EB Cure . . . . . . . . . . . . . .
F a b r i c a t i o n o f L a s e r v i s i o n Video Discs . . . . . . . . . . . . . . .
Electron-Beam Processing System f o r Wire.Cable . . . . . . . . . . . .
A p p l i c a t i o n s o f Plasma Processing Technologies . . . . . . . . . . .
H i s t o r i c a l Growth P a t t e r n f o r t h e Coating I n d u s t r y . . . . . . . . . .
Major Market Segments f o r I n d u s t r i a l Product F i n i s h e s . . . . . . . .
H i s t o r i c a l Growth P a t t e r n f o r t h e Wood F i n i s h i n g I n d u s t r y . . . . . .
Shipments Reported f o r Metal D e c o r a t i v e Coatings Market . . . . . . .
Packaging C o a t i n g Shipments . . . . . . . . . . . . . . . . . . . . .
Shipment Values Reported f o r P r i n t i n g I n k s . . . . . . . . . . . . .
Market Share o f Major P r i n t i n g Processes . . . . . . . . . . . . . . .
Shipments Reported f o r Adhesives I n d u s t r y . . . . . . . . . . . . . .
Shipments o f Pressure S e n s i t i v e Adhesives . . . . . . . . . . . . . .
Electron-Beam P a t t e r n i n g System
4-52
4-53
4-54
4-56
4-63
4-64
4-67
4-71
4-78
6-3
6-6
6-7
6-10
6-13
6-15
6-16
6-20
6-22
Share o f Low D e n s i t y P o l y e t h y l e n e (LDPE) and P o l y v i n y l C h l o r i d e
(PVC) Annual P l a s t i c s P r o d u c t i o n C a p a c i t y
6-23
1985 Market Share f o r Low D e n s i t y P o l y e t h y l e n e (LDPE) and
P o l y v i n y l C h l o r i d e (PVC)
6-24
..............
......................
I C Shipments . . . . . . . . . . . . . . . . . . . . . . . . . . . .
U.S. E l e c t r o n i c Chemicals . . . . . . . . . . . . . . . . . . . . . .
xi
.
.
6-27
6-28
Page
Figure
.................
.................
6-14 U.S.
Electronic Chemicals for Devices
6-29
6-15 U.S.
Device Encapsulant Consumption
6-30
xii
.
TABLES
Table
1-1
2-1
2-2
2-3
2-4
Page
.......................
Normal T o t a l E m i s s i v i t y o f Various S u b s t r a t e s . . . . . . . . . . . .
C h a r a c t e r i s t i c s o f Commercially Used I n f r a r e d Heat Sources . . . . . .
UV Lamp O p e r a t i n g C h a r a c t e r i s t i c s . . . . . . . . . . . . . . . . . .
E l e c t r o m a g n e t i c Spectrum
1-1
2-9
2-14
2-18
O p e r a t i o n a l C h a r a c t e r i s t i c s o f E l e c t r o d e and E l e c t r o d e l e s s
Medium Pressure Mercury Arc Lamp
2-19
2-5
UV C u r i n g Equipment
2-21
2-6
Comparisons Between P l a n a r Cathode and Swept Beam High
Energy E l e c t r o n Processing Equipment
2-26
3-1
I n f r a r e d o r Thermal R a d i a t i o n
3-4
3-2
P h o t o i n i t i a t o r s Used i n U l t r a v i o l e t R a d i a t i o n Curable
Polymeric M a t e r i a1 s
3-3
3-4
4-1
4-2
4-3
...................
.........................
.................
Processing Chemistry . . . . . . . . .
.........................
M a t e r i a l s Used i n R a d i a t i o n (UV and EB) Curable Coatings . . . . . . .
Photocurable Polymer Systems . . . . . . . . . . . . . . . . . . . . .
Coatings I n d u s t r y . P a i n t s and A l l i e d Products ( S I C 28500-005) . . . .
R a d i a t i o n Curable Coatings f o r Wood F i n i s h i n g A p p l i c a t i o n s . . . . . .
3-6
3-6
3-9
4-3
4-10
Comparison o f Performance L i m i t s and Test Values Between H i g h
and Low Pressure Me1 amine Thermal l y Cured Laminates and U n i f ace
E l e c t r o n ' Beam Cured Panels
4-12
P r o p e r t i e s o f T y p i c a l UV Curable Coatings f o r Galvanized
S t e e l Tubing
4-17
Comparison o f P r o p e r t i e s f o r Conventional and R a d i a t i o n C u r a b l e
Coatings f o r V i n y l F l o o r i n g Products
4-19
Average P r o p e r t i e s o r R a d i a t i o n Curable Coatings i n Magnet Wire
Applications
4-23
4-7
Printing
4-25
4-8
Standard
......................
4-4
4-5
4-6
.............................
.................
.............................
I n d u s t r y Product D i v e r s i t y . . . . . . . . . . . . . . . . .
(Conventional Thermal Cure) and UV/EB I n k F o r m u l a t i o n s . . .
xiii
4-34
Tab1 e
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
4-22
4-23
4-24
Page
...............
Adhesives I n d u s t r y Polymer-Solvent C l a s s i f i c a t i o n . . . . . . . . . .
Adhesive Techno1 o g i es . . . . . . . . . . . . . . . . . . . . . . . .
S t r u c t u r a l and S p e c i a l t y Adhesives Markets . . . . . . . . . . . . . .
Advantages o f High-Energy E l e c t r o n Adhesives . . . . . . . . . . . . .
T y p i c a l Products Prepared With a Planar Cathode E l e c t r o n Processor . .
Adhesive F i l m A p p l i c a t i o n Areas . . . . . . . . . . . . . . . . . . .
Photo1 it h o g r a p h i c Processes . . . . . . . . . . . . . . . . . . . . .
Adhesives Market S u p p l i e r s and Products
P r o p e r t i e s o f Two S t a k i n g Compounds f o r SMD Thermal Versus
UV Curable M a t e r i a l s
.........................
Adhesives Surface Mounting Device (SMD) Requirements . . . . . . . . .
Major Types o f P r i n t e d C i r c u i t Boards . . . . . . . . . . . . . . . .
P r o p e r t i e s of Screen I n k Systems . . . . . . . . . . . . . . . . . . .
Comparison o f Various Means of Transmission . . . . . . . . . . . . .
S e l e c t e d A p p l i c a t i o n Areas f o r I r r a d i a t e d Polymer M a t e r i a l s . . . . .
Comparison o f P h y s i c a l P r o p e r t i e s f o r Conventional 105' C PVC
and I r r a d i a t e d PVC Wire Compounds
..................
E f f e c t o f S p e c i f i c G r a v i t y o f a M a t e r i a l on t h e Depth of
E l e c t r o n Beam P e n e t r a t i o n a t Two E l e c t r o n A c c e l e r a t o r V o l t a g e s
....
..
4-38
4-40
4-41
4-42
4-42
4-45
4-46
4-55
4-57
4-58
4-60
4-61
4-65
4-68
4-69
4-70
4-25
Comparison of Chemical V u l c a n i z a t i o n Versus I r r a d i a t i o n P r o c e s s i n g
4-26
Rubber Market D i s t r i b u t i o n
4-75
4-27
Applications f o r
4-76
4-28
Re1 a t i v e Adhesive Bond S t r e n g t h s f o r Plasma and Conventional
Methods o f T r e a t i n g Polymer Surfaces
4-29
5-1
5-2
5-3
......................
R a d i a t i o n Processed E l a s t o m e r i c M a t e r i a l s . . . . . .
.................
Plasma Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . .
UV and I R Processing Cost and Energy E f f i c i e n c y Data . . . . . . . . .
4-73
4-77
4-77
5-3
Comparison o f UV Versus Gas F i r e d Thermal Cure C o a t i n g / I n k Systems
f o r Beverage C o n t a i n e r s
5-4
O p e r a t i n g Cost A n a l y s i s f o r R a d i a t i o n Versus Thermal Processing
Equipment f o r C o a t i n g Aluminum C o i l Stock
5-5
.......................
..............
xiv
.
.
Page
Table
Comparison o f Energy Requirements f o r D i f f e r e n t Energy Sources
on a Model C o i l Coating L i n e .
5-7
Comparative Cost A n a l y s i s f o r High Energy E l e c t r o n Cured C o a t i n g
Systems Versus Conventional Thermally Cured C o a t i n g Systems on
Aluminum C o i l Stock
5-8
5-6
Comparison o f
5-9
5-7
Comparison o f
5-8
Comparison o f Annual O p e r a t i n g Cost, P r o d u c t i o n and Cost Savings
Between a Conventional UV L i n e a r R a d i a t i o n Processor and a Compact
On-Mandrel UV Processor
5 -4
5-5
5-9
5-10
5-11
5-12
5-13
5-14
5-15
6-1
....................
.........................
C u r i n g Methods. . . . . . . . . . . . . . . . . . . . .
Dryer Processing Costs f o r P r i n t i n g A p p l i c a t i o n s . . . .
.......................
Cost Savings Comparisons Between Conventional UV and On-Mandrel UV
Processors f o r a P l a n t Rated a t 1.12 B i l l i o n P r i n t e d Cup C a p a c i t y . .
P r e l i m i n a r y Cost Comparison f o r Thermal and E l e c t r o n Beam C u r i n g
o f Adhesi ves
.............................
.
Economics, Photochemical vs Thermal P r o d u c t i o n L i n e s PressureS e n s i t i v e Adhesive Tape and Labels.
.................
Energy Comparison, CV and EB, f o r Wire I n s u l a t i o n C r o s s - l i n k i n g . . .
Cost Comparison Data (CV/EB). . , . . . . . . . . . . . . . . . . . .
Estimated Cost t o Plasma T r e a t Small Objects. . . . . . . . . . . . .
Estimated Cost t o Plasma T r e a t a Continuous Web o f PVC F i l m . . . . .
R a d i a t i o n Processing End Use Markets and Products . . . . . . . . . .
5-11
5-12
5-13
5-14
5-15
5-17
5-18
5-20
5-21
6-2
Annual Shipment Values f o r t h e I n d u s t r i a l Product F i n i s h i n g ( I P F )
Market; Gross N a t i o n a l Product (GNP) Values and IPF/GNP R a t i o s .
...
6-5
6-3
A n a l y s i s o f Conventional and R a d i a t i o n Curable Coatings f o r Wood
F i n i s h i n g Market Areas.
.......................
6-9
6-4
A n a l y s i s o f Conventional and R a d i a t i o n Curable Coatings f o r Metal
F in is h i ng M ark e t Are as
6-11
A n a l y s i s o f Conventional and R a d i a t i o n Curable Coatings f o r
P ac k ag ing Market Areas
6-12
6- 6
Annual Shipment Values f o r P r i n t i n g I n k s ; Gross N a t i o n a l Product
Values and P I / G N P R a t i o s .
6-17
6- 7
Conventional and R a d i a t i o n Curable P r i n t i n g I n k I n d u s t r y
Market A n a l y s i s
6-18
6-2
6-5
6-8
........................
........................
......................
...........................
H i s t o r i c a l Growth o f S y n t h e t i c and Rubber Adhesives (AD);
Val ues and AD/GNP R a t i o s .
GNP
......................
xv
6-21
Page
Table
6-9
Conventional and R a d i a t i o n Curable S y n t h e t i c and Rubber Adhesive
Market A n a l y s i s .
6-21
6-10
U.S.
6-26
6-11
Magnetic Media Market
6-12
R a d i a t i o n Processing o f Polymeric M a t e r i a l s Markets and Growth
Potential
6-32
6-13
Radiation
6-33
6-14
U.S. Shipments o f I n d u s t r i a l F i n i s h e s b y Coatings M a t e r i a l s and
Systems..
6-15
6-16
6-17
Synthetic
...........................
and N a t u r a l Rubber Consumption. . . . . . . . . . . . .
........................
..............................
Processing Equipment (Growth and Major Market Areas). . . .
.............................
Energy A n a l y s i s o f C o a t i n g Technologies . . . . . . . . . . . . . . .
6-31
6-35
6-36
Cost Comparison o f E l e c t r o n Beam t o Hot A i r Convection C u r i n g
Systems f o r Wheel Rims.
6-38
Comparison Between EB C u r i n g and Thermal Curing C o a t i n g
System on E l e c t r o g a l v a n i z e d S t e e l
6-40
.......................
..................
xv i
SU MM A R Y
The a p p l i c a t i o n o f e l e c t r o m a g n e t i c r a d i a t i o n t o p o l y m e r i c m a t e r i a l s can l e a d t o
t h e f o r m a t i on o f three-dimensional network s t r u c t u r e s , which g e n e r a l l y improve
t h e o v e r a l l p h y s i c a l o r chemical p r o p e r t i e s of t h e o r i g i n a l s u b s t r a t e .
This use o f
e l e c t r o m a g n e t i c r a d i a t i o n t o a1 t e r t h e p h y s i c a l and chemical n a t u r e o f a p o l y m e r i c
m a t e r i a1 i s termed r a d i at ion-processing o r r a d i a t i o n - c u r i n g techno1 ogy.
Radiation
processing, as a p p l i e d t o c r o s s - l i n k i n g (network f o r m a t i o n ) o f polymer, i n k , adhes i v e , o r c o a t i n g m a t e r i a l s , i n v o l v e s t h e f u l l spectrum of e l e c t r o m a g n e t i c r a d i a t i o n
e n e r g i e s t o e f f e c t chemical r e a c t i o n s .
i o n i z i n g r a d i a t i o n (i.e.,
These forms o f r a d i a t i o n energy i n c l u d e
a, 6, and y r a y s from r a d i o a c t i v e n u c l e i ) ,
X-rays,
high--
energy e l e c t r o n s , and n o n i o n i z i n g r a d i a t i o n a s s o c i a t e d w i t h t h e u l t r a v i o l e t ( U V ) ,
v i s i b l e , i n f r a r e d ( I R ) , microwave, and r a d i o frequency wavelengths o f energy.
R a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s r e q u i r e s t h a t e l e c t r i c a l energy be
c o n v e r t e d t o some f o r m o f e l e c t r o m a g n e t i c r a d i a t i o n energy w i t h s u f f i c i e n t power o r
i n t e n s i t y t o be c o m m e r c i a l l y f e a s i b l e .
The most common r a d i a t i o n sources o r equip-
ment f o r t h e commercial c r o s s - l i n k i n g o f p o l y m e r i c m a t e r i a l s a r e i n f r a r e d lamps ,
u l t r a v i o l e t l i g h t sources , low- and high-energy e l e c t r o n a c c e l e r a t o r s , and plasma
o r glow-discharge energy sources.
T y p i c a l l y t h e m a t e r i a l t h a t i s processed passes
t h r o u g h a d r y i n g area o r oven f o r i r r a d i a t i o n .
R a d i a t i o n p r o c e s s i n g o f m a t e r i a l s i s a technology based on t h e f o l l o w i n g :
0
Chemical r e a c t i o n s o f s m a l l monomer o r oligomer components
( m o l e c u l a r weight, ca 100-1,000) t o fprm l a r g e polymer
components (molecular weight, ca 1,000-25,000
infinite).
-
0
Small monomer-oligomer components combining t o g e t h e r w i t h l a r g e
preformed polymer components.
0
Connecting l a r g e polymer components t o g e t h e r .
0
Changing t h e s u r f ace c h e m i s t r y o f l a r g e polymer components f o r
improved chemical o r p h y s i c a l p r o p e r t i e s
s-1
The o v e r a l l c h e m i s t r y o r chemical r e a c t i o n s o f m a t e r i a l s a s s o c i a t e d w i t h t h i s t e c h n o l o g y can be f u r t h e r c l a s s i f i e d as thermal ( c o n v e n t i o n a l ), UV l i g h t - i n d u c e d
(photochemical o r photopolymeri z a t i o n ) , h i g h energy e l e c t r o n , and plasma processes.
R a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s has found widespread commercial use i n
t h e f o l l o w i n g areas:
0
Coatings
P r i n t ing
Adhes ives
0
Electronics/communications
0
0
P l a s t i c s and rubber m a t e r i a l s
Plasma processing
0
0
The advantages o f r a d i a t i o n p r o c e s s i n g polymer t e c h n o l o g i e s over t h o s e o f convent i o n a l f o s s i l energy-heated p r o c e s s i n g techniques i n these areas i n c l u d e :
Rapid d r y i n g speeds (seconds o r l e s s ) .
Reduction o r e l i m i n a t i o n o f o r g a n i c s o l v e n t s , thus e l i m i n a t i n g
a i r p o l l u t i o n and i n c i n e r a t i o n problems.
S i g n i f i c a n t r e d u c t i o n o r e l i m i n a t i o n o f f o s s i l energy-heated
d r y i n g ovens and i n c i n e r a t o r s .
Coating o f heat-sensi t i ve m a t e r i a1s ( p l a s t i c s 1.
Increased production r a t e s .
More e f f i c i e n t use o f p o l y m e r i c c o a t i n g m a t e r i a l s because o f
less penetration of flowing material i n t o substrates.
Savings i n space o f a p p l i c a t i o n equipment.
Manufacture o f p r o d u c t s w i t h h i g h value-added p r o p e r t i e s .
Development o f p r o d u c t s t h a t cannot be manufactured b y any
o t h e r p r o c e s s i n g technique.
I n t h e U n i t e d S t a t e s i t i s e s t i m a t e d t h a t t h e t o t a l use o f r a d i a t i o n p r o c e s s i b l e
m a t e r i a l i s v a l u e d a t a p p r o x i m a t e l y $0.7 t o $1.1 b i l l i o n and i s expected t o
i n c r e a s e between $1.4 and $1.8 b i l l i o n i n 1990.
3035 t o t a l r a d i a t i o n (UV,
Currently t h e r e are approximately
EB, I R ) p r o c e s s i n g u n i t s i n t h e U n i t e d S t a t e s which a r e
r a t e d a t a t o t a l ( c u m u l a t i v e ) c a p a c i t y of 430,000 kw.
I n 1990 t h e t o t a l number of
p r o c e s s i n g u n i t s i s expected t o r e a c h 8610 u n i t s f o r a t o t a l r a t e d c a p a c i t y o f
1,500,000
kw.
European and Japan e s t i m a t e s f o r r a d i a t i o n p r o c e s s i b l e m a t e r i a l s a r e
valued a t a p p r o x i m a t e l y $0.3 t o $0.6 and $0.1 t o $0.4 b i l l i o n r e s p e c t i v e l y .
s-2
These
values should i n c r e a s e t o $0.7 t o $0.95 b i l l i o n (Europe) and $0.8 b i l l i o n (Japan)
i n t h e y e a r 1990.
The t o t a l number o f r a d i a t i o n p r o c e s s i n g u n i t s f o r Europe i s
a p p r o x i m a t e l y 2990 u n i t s (500,000 kw t o t a l c a p a c i t y r a t i n g ) and a p p r o x i m a t e l y 1690
u n i t s (300,000 kw t o t a l c a p a c i t y r a t i n g ) a r e c u r r e n t l y i n s t a l l e d i n Japan.
y e a r 1990 t h e number o f u n i t s i s expected t o i n c r e a s e t o 8610 (1,500,000
I n the
kw capac-
i t y r a t i n g ) and 2500 (430,000 kw t o t a l c a p a c i t y r a t i n g ) f o r Europe and Japan
.
r e s p e c t iv e l y
The t o t a l impact o f r a d i a t i o n p r o c e s s i n g of p o l y m e r i c m a t e r i a l s , w h i l e s i g n i f i c a n t ,
i s s t i l l a minor p a r t o f t h e t o t a l p r o d u c t m a n u f a c t u r i n g t e c h n i q u e s c u r r e n t l y i n
use today.
The o v e r a l l annual growth r a t e f o r r a d i a t i o n p r o c e s s i n g techniques i s
p r o j e c t e d t o be between 10 t o 20%, thus i t i s an a t t r a c t i v e area f o r f u t u r e r e search and development a c t i v i t y .
Several f u t u r e developments expected f o r t h i s
t e c h n o l o g y can be d e s c r i b e d as f o l l o w s :
0
Continued r e s e a r c h i n h i g h energy p h y s i c s d i r e c t e d a t e l e c t r o n
beam a c c e l e r a t o r s f o r beam p r o p a g a t i o n , maintenance and
control.
0
Continued r e s e a r c h and development i n UV and I R p r o c e s s i n g
equ ipment
0
Development o f new r a d i a t i o n s e n s i t i v e p o l y m e r i c m a t e r i a l s .
0
Development o f new s p e c i a l t y p r o d u c t s and markets f o r r a d i a t i o n
processing technologies.
0
Reduction i n m a t e r i a l c o s t s ( l o w e r c o a t i n g c o s t s ) t o t h e u s e r
o r product f i n i s h e r .
.
The p r e s e n t b e n e f i t s f r o m r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s a r e d e r i v e d
from improved q u a l i t y , s p e c i a l p r o p e r t i e s and h i g h e r p r o d u c t i v i t y .
The advantages
of low-energy consumption and low p o l l u t i o n a r e g e n e r a l l y secondary c o n s i d e r a t i o n s
b u t t h i s c o u l d change d r a m a t i c a l l y depending on EPA r u l i n g s and a v a i l a b i l i t y o f
f o s s i l f u e l supplies.
Increased usage o f r a d i a t i o n p r o c e s s i n g of p o l y m e r i c systems
w i l l depend on m a t e r i a l c o s t s and addressing t h e t e c h n i c a l v o i d s p r e v i o u s l y d i s cussed above, as w e l l as, t h e e f f e c t s o f competing t e c h n o l o g i e s w i t h i n s p e c i f i c
market areas.
However , t h e r a p i d cure, low p r o c e s s i n g temperatures , and develop-
ment o f s p e c i a l t y p r o d u c t s w i l l i n s u r e t h a t r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s w i l l
c o n t i n u e t o grow i n importance t h r o u g h o u t t h e world.
s-3
Section 1
INTRODUCTION
The a p p l i c a t i o n o f e l e c t r o m a g n e t i c r a d i a t i o n t o p o l y m e r i c m a t e r i a l s can l e a d t o
t h e f o r m a t i o n o f three-dimensional network s t r u c t u r e s , which g e n e r a l l y improve
t h e o v e r a l l p h y s i c a l o r chemical p r o p e r t i e s o f t h e o r i g i n a l s u b s t r a t e .
T h i s use o f
e l e c t r o m a g n e t i c r a d i a t i o n t o a1 t e r t h e p h y s i c a l and chemical n a t u r e o f a p o l y m e r i c
m a t e r i a l i s termed r a d i a t i o n - p r o c e s s i n g o r r a d i a t i o n - c u r i n g technology.
Radiation
processing, as a p p l i e d t o c r o s s - l i n k i n g (network f o r m a t i o n ) o f polymer, i n k , adhes i v e , o r c o a t i n g m a t e r i a l s , i n v o l v e s t h e f u l l spectrum of e l e c t r o m a g n e t i c r a d i a t i o n
e n e r g i e s t o e f f e c t chemical r e a c t i o n s .
i o n i z i n g r a d i a t i o n (i.e.,
These forms of r a d i a t i o n energy i n c l u d e
a , B , and y r a y s f r o m r a d i o a c t i v e n u c l e i ) , X-rays,
high--
energy e l e c t r o n s , and n o n i o n i z i n g r a d i a t i o n a s s o c i a t e d w i t h t h e u l t r a v i o l e t ( U V ) ,
v i s i b l e , i n f r a r e d ( I R ) , microwave, and r a d i o frequency wavelengths o f energy (see
1)
T a b l e 1-1 and F i g u r e 1-1). (-
Table 1-1
ELECTROMAGNETIC SPECTRUM
Types o f R a d i a t i o n
Gamma r a y
E l e c t r o n beam
X-ray
U 1t r a v i o l e t
Visible
In f r a r e d
Microwave
Radio Frequency
Wavelengths , nm
10-~-10-~
10-3 - 1 ~ 10-2-10
10-400
400-750
750-105
>lo6
>lo6
(1)
Frequency, Hz
Energy, eV
1019-1~22
1018- 1021
10~~-10~9
1 0 ~ ~ - 1 0 ~ ~
105-108
104-107
102-105
5-lo2
1-5
10~~-10~4
l o l l - 1012
<loll
10-2-1
<lo-2
<lo-2
I n general, r a d i a t i o n processing ( c u r i n g or c r o s s - l i n k i n g ) o f polymeric materials
and t h e r e l a t e d t e c h n o l o g i e s i n v o l v e s f o u r main c o n s i d e r a t i o n s :
the type of radia-
t i o n and a s s o c i a t e d p r o c e s s i n g equipment; t h e n a t u r e of t h e p o l y m e r i c m a t e r i a l s t o
be i r r a d i a t e d and t h e i r response c h a r a c t e r i s t i c s ; mechanisms o r t h e o r i e s o f r e a c -
1-1
0.76
I
0.38
I
Gm"
Rays
I
9-oi'/
Long-Wave I.R.
L
1m
1 mm
10-6
10-3
I
Radio Waves
lm
\oo
1 km
103 m
Temperature of Peak Radiated Energy
O
3000
500
212OF
L
Ultra
Violet
I
Infra-Red
Rays
Ultra Violet
Rays
1 nm
Wavelength
1 mm
4 pm
I
Visible Short- Medium
Light Wave Wave
I.R.
I.R.
X-Rays
ro
2
I
Visible
Light
0.3
Near
0.72
Middle I.R.
I.R.
1.5
Figure 1-1.
Far I.R.
5.6
1,000 pm Wavelength
8
Electromagnetic Spectrum
(1)
1 1
I
t i o n ; and chemical , p h y s i c a l and mechanical p r o p e r t i e s r e s u l t i n g f r o m t h e f o r m a t i o n
2)
o f p o l y m e r i c network s t r u c t u r e s . (that follow.
These v a r i a b l e s a r e discussed i n t h e s e c t i o n s
With t h i s as background, a p p l i c a t i o n s and markets as w e l l as s a l e s
p r o j e c t i o n s a r e assessed.
The r e p o r t concludes w i t h a sumnary o f areas i n which
R&D i n t h e c u r i n g area would h e l p t o advance t h e s t a t e o f t h e a r t .
1-3
Section 2
RADIATION PROCESSING EQUIPMENT
Radiation processing of polymeric materials requires t h a t e l e c t r i c a l energy be
converted t o some form of electromagnetic radiation energy with s u f f i c i e n t power or
i n t e n s i t y t o be commercially f e a s i b l e . The most common radiation sources or equipment f o r the commercial cross-linking of polymeric materials are infrared lamps ,
u l t r a v i o l e t l i g h t sources , low- and high-energy electron accelerators , and plasma
or glow-discharge energy sources. Typically the material t h a t i s processed passes
t h r o u g h a drying area or oven f o r i r r a d i a t i o n .
(3)
INFRARED RADIATION PROCESSING EQUIPMENT
Infrared (IR) radiation i s the part of the electromagnetic spectrum having wavelengths between 0.7 and 1,000 microns (Figure 1-11. ( 3 , 4 ) An important commercial
use of infrared radiation i s t o thermally drive off solvents or water from an ink
or coating system, and t o bring about curing of the ink or coating through oxidat i o n i n a i r or t h r o u g h other forms of thermally activated chemical reaction processes. In p r a c t i c e t h r e e basic types of IR emitter equipment are available: those
t h a t produce long-wave ( 4 - 1 0 0 0 ~ ,) medium-wave (2-4p) , and short-wave (0.7-2p) IR
- Long-wave IR emitters generate considerable amounts of heat, b u t
r a d i a t i o n . (5,6)
tend t o be more d i f f i c u l t t o d i r e c t onto a s u b s t r a t e . T h i s type o f thermal radiat i o n i s d i f f i c u l t t o r e t a i n within the drying (oven) area because the longer wavelengths of IR radiation are s c a t t e r e d by a i r . There i s more s t r a y heat and l i t t l e
penetration c a p a b i l i t y ; i t e s s e n t i a l l y causes only surface drying of inks and coatings a t the expense of g r e a t l y increased dwell times in the processing unit (Figure
2-1). Medium-wave IR emitters produce IR i r r a d i a t i o n t h a t penetrates the i n k or
coating surface a l l the way through t o the s u b s t r a t e (Figure 2-2). Short-wave IR
emitters focus IR radiation t o a h i g h i n t e n s i t y f o r curing thick films in a very
short period of time (Figure 2-3). In contrast t o long-wave IR e m i t t e r s , short-wave IR emitters are very e f f i c i e n t and exhibit very l i t t l e heat loss t o the surrounding oven areas.
One f a c t o r i n considering the use of IR radiation in commercial applications i s
emitter e f f i c i e n c y . The t h e o r e t i c a l r e l a t i o n s h i p between a given IR emitter temperature and maximum i n t e n s i t y wavelength i s shown in Figure 2-4. In p r a c t i c e ,
2-1
I.R.
Emitter
J
\ Substrate
Figure 2-1.
Schematic o f Application o f Long Wave IR Radiation
2-2
(6)
I.R. Emitter
Substrate
Figure 2-2.
Schematic of Application of Medium Wave IR Radiation
2-3
(6)
-
I.R. Emitter
F i g u r e 2-3.
Schematic of A p p l i c a t i o n of S h o r t Wave I R R a d i a t i o n
2-4
(6)
0
0
0
0
z
0
cu
2-5
however, an IR emitter exhibits a broad d i s t r i b u t i o n of wavelengths ( c f . Figure
2-51 - where the operating temperature of the emitter corresponds t o the maximum
p o i n t of each d i s t r i b u t i o n curve. As the emitter temperature decreases, so does
the emitted energy from the IR source. This d r o p off in emitted energy can be
described as f o l l ows :
4
Emitted Energy = (emissivity) (constant) (absolute temperature of the emi t t e r )
or E = E O T4
The e f f i c i e n c y of a radiating surface i s character zed by i t s emissiv t y ( € 1 . An
emissivity value of 1 r e l a t e s t o perfect energy conversion t o electromagnetic waves
from the primary energy source (e.g., e l e c t r i c a l r e s i s t a n c e source, gas- or o i l - f i r e d source) (Figure 2-6).
Another f a c t o r t o consider i s the e f f e c t of emitted energy on the coating or subs t r a t e undergoing the radiation processing operation. Under these conditions emiss i v i t y appears t o be d i r e c t l y proportional t o the absorptivity of the materials
being processed a t a p a r t i c u l a r wavelength and surface temperature. (Table 2 - 1 ) .
Selective absorption of IR energy by c e r t a i n ink and coating formulations can also
become an important overall curing efficiency f a c t o r ; short-wave IR radiation i s
more r e f l e c t i v e from surfaces with highly colored or r e f l e c t i v e pigments than i s
long-wave IR radiation (Figure 2 - 7 ) .
Infrared radiation emitter processing equipment can be divided i n t o two general
c l a s s e s : one using gas- or oil-burning units and the other using e l e c t r i c a l
energy. Figures 2-8, 2-9, and 2-10 depict common types of IR emitter systems;
Table 2-2 l i s t s the major c h a r a c t e r i s t i c s associated with e l e c t r i c a l l y activated IR
emitter devices. (3-6)
ULTRAVIOLET ( U V ) LIGHT SOURCES
U l t r a v i o l e t ( U V ) radiation i s the part of the electromagnetic spectrum having wavelengths from 4 t o 400 nanometers. The basic energy source f o r i n i t i a t i n g reactions
of UV responsive materials is the mercury vapor lamp. The major lamp systems in
commercial use today are as follows:
0
Low mercury pressure
0
Medium pressure (1 t o 2 atmospheres) mercury vapor lamps having
electrode configurations f o r operation.
(
torr
2-6
germicidal 1 amps.
2-7
-I
2
Btu Per Sq. Ft. Per Hour at Various
Emissivity Values
a
4
4
5 %
(D
n
0
I
I
I
I
4
4
4
53
5!
B
I
I
I
I
I
I
I
I
I
I
n
v
P
0
0
m
0
0
4
h)
0
0
4
Q,
0
0
lo
0
0
0
h)
P
0
0
h)
m
0
0
I
I
1 1
I
Table 2-1
NORMAL TOTAL E M I S S I V I T Y OF VARIOUS SUBSTRATES
S u r f ace
Aluminum, Commercial Sheet
Brass, D u l l P l a t e
Copper, P o l i s h e d
Gold, Pure, H i g h l y P o l i s h e d
Steel
, Pol ished
Iron, Polished
Oxidized, I r o n , Dark-Gray Surface
S t a i n l e s s Steel, Polished
Stainless Steel
, Type
301;B
Tin, B r i g h t Tinned I r o n
Tungsten F i 1ament
Zinc, Galvanized Sheet I r o n , F a i r l y B r i g h t
Asbestos, Board
Brick, Fireclay
Enamel, White Fused, on I r o n
(5)
T, OF
E m i ss iv i t y
212
120-660
242
440-1160
212
800-1880
212
212
450-1725
76
6000
82
74
1832
66
0.09
0.22
0.023
0.018-0.035
0.066
0.14-0.38
0.31
0.074
0.54-0.63
0.045 & 0.064
0.39
0.23
0.96
0.75
0.90
73
76
70
170-295
100-200
100-200
69
74
32-212
0.906
0.875
0.821
0.91
0.80-0.95
0.96-0 e98
0.91
0.94
0.95-0.963
P a i n t s , Lacquers, Varnishes:
Snow-white enamel v a r n i s h on rough i r o n p l a t e
Black s h i n y l a c q u e r , sprayed on i r o n
Black s h i n y s h e l l a c on t i n n e d i r o n sheet
Black m a t t e s h e l l a c
Black o r w h i t e l a c q u e r
F1a t b l a c k 1acquer
R o o f i n g , Paper
Rubber, Hard Glossy P l a t e
Water
2-9
100
90 -
I\
80
-
70
-
60
-
50
-
40
-
30
-
20
-
3
1
2
3
4
5
6
7
Peak Wave Length (microns)
F i g u r e 2-7.
S e l e c t i v e Absorption o f
IR R a d i a t i o n by Various S u b s t r a t e s
2-1 0
(4)
-
Exhaust
Gas
Combustion
Fuel
and Air
Inlet
IR Radiation Emission
/
FueVAir
Inlet
IR Emission
Impingement
Flame
Combustion
f
Refractory
Surface
F i g u r e 2-8.
Common IR R a d i a t i o n E m i t t e r s
2-1 1
-
Fuel Burning Types
(3)
Boro-Silicate
Glass Bulb
Tungsten
Filament
Electrodes
Ceramic or Quartz
Plate Element
Nichrome Wire Coil
Figure 2-9.
Common IR Radiation Emitters
2-1 2
-
E l e c t r i c a l Types
(3)
2-1 3
Table 2-2
CHARACTERISTICS OF COMMERCIALLY USED INFRARED HEAT SOURCES ( 3)
Tungsten
T3 Quartz Lamp
Quartz Tube
Metal Sheath
Source Temperature
Normal Max.
Usual Range
4000OF
3000 to
40000F
4000OF
3000 to
4000OF
1600OF
1800 to
1400OF
1200OF
1400 to
lOOOOF
Brightness
Bright
White
Heat
Bright
White
Heat
Cherry
Red
Dull
Red
6-30
318" di a.
3 f 8 or 5f8"
3f8 or 518"
Usual Size
Lamp
Tube
dia. tube
dia. tube
Wavelength at Energy
Peak - Normal Max.
(Emissivity)
1.15
1.15
2.6
3.1
Micron
Micron
Micron
Micron
(0.86)
(0.62)
(0.56)
1.5 to 1.15
Micron
1.5 to 1.15
Micron
2.6 to 2.8
Micron
86%
20%
86%
14%
65-80%
32-20%
72-86%
28-14%
I
P
Nichrome Spiral Winding
Glass Bulb
N
2
Filament Wire
Usual Range
Relative Energy
Distribution
Normal Maximum
Radiation
Convection & Cond.
Usual Range
Radiation
Convection & Cond.
Low Temperature
Panel Heaters
Buried
Metallic
Nichrome Salt
-
Gas Infrared Burners
Perforated
Impingement
Tile Type
Type
600-8OOOF
1700OF
2200OF
1100-4OOOF
1400-155OOF
1400-205OOF
No
Visible
Light
Soft Red
Bright Red
3 x 22 or
5 x 22"
3 x 12"
Flat panels
Various
-
Around
4-5 Micron
2.6
2.2
Micron
Micron
2.8 to 3.6
Micron
3.2 to 6
Micron
2.5 to 2.8
Micron
2.2 to 2.8
Micron
55%
45%
50%
50%
40-30%
60-70%
54%
46%
44%
56%
5545%
4545%
53-45%
47-55%
50-20%
50-80%
46-50%
54-50%
36-40%
64-60%
Degree of Heat Penetration
Depth of penetration varies with the characteristics of the product. As a general rule,
energy of shorter wavelengths penetrates deeper than energy of longer wavelengths.
Relative response to
Heatup-Cooldown
seconds
seconds
Color Sensitivity
Bodies of different colors can be heated at more nearly the same rate by infrared
radiation with long wavelengths than they can by short wavelength infrared radiation.
Ruggedness
Mechanical Shock
Thermal Shock
poor
poor
Average life (hrs)
: I
seconds
seconds
good
excellent
5,000
I
minutes
seconds
good
excellent
10,000
minutes
minutes
excel 1 ent
excel lent
score of minutes
scores of minutes
varies with panel
design - could be
quite good
1 min to 60%
1 min to 18%
3 min to 60%
7 min to 18%
fair
excellent
poor
fair
10-20,000
I ,
I
0
Medium pressure mercury vapor lamps a c t i v a t e d b y microwave
energy r a d i a t i o n and t h u s do n o t r e q u i r e e l e c t r o d e s ( e l e c t r o d e l e s s lamp o p e r a t i o n developed by Fusion Systems C o r p o r a t i o n ) .
0
F l a s h lamps o r p u l s e d xenon gas a r c s .
0
Metal doped o r h y b r i d xenon/mercury vapor lamp systems.
D e s c r i p t i o n o f t h e power s u p p l i e s , t y p i c a l lamp c o n f i g u r a t i o n s
, and
design c o n s i d -
e r a t i o n s f o r low mercury pressure, medium mercury pressure, and f l a s h lamps a r e
g i v e n i n F i g u r e s 2-11 and 2-12.
General o p e r a t i n g c h a r a c t e r i s t i c s f o r s e v e r a l o f
7)
t h e s e lamp systems a r e l i s t e d i n Table 2-3. ( The two major lamp systems having commercial r a d i a t i o n p r o c e s s i n g s i g n i f i c a n c e
t o d a y are t h e c o n v e n t i o n a l e l e c t r o d e and e l e c t r o d e l e s s (Fusion Systems C o r p o r a t i o n )
medium p r e s s u r e mercury arcs.
A d i r e c t o p e r a t i o n a l c h a r a c t e r i s t i c comparison be-
(8 ) E i t h e r UV lamp system i s housed i n a
tween each lamp i s g i v e n i n Table 2-4.
r e f l e c t o r and must be c o o l e d w i t h a i r o r water t o promote e f f i c i e n t lamp o p e r a t i o n
and a reasonable l i f e expectancy.
A t y p i c a l l i n e a r a r r a y o f e l e c t r o d e lamps, e l e c -
t r o d e l e s s lamp system, r e f l e c t o r s , and methods o f c o o l i n g i s shown i n F i g u r e 2-13.
F u r t h e r developments i n c o o l i n g , gas i n e r t b l a n k e t i n g , f i l t e r i n g o f unwanted excess
i n f r a r e d r a d i a t i o n (which i s always p r e s e n t i n t h e o u t p u t s p e c t r a o f a mercury
lamp), and novel lamp housing o r equipment have been pioneered b y Union Carbide
Corporation.
A complete r e v i e w o f l i g h t sources used i n photo-processing a p p l i c a -
t i o n i s g i v e n i n r e f e r e n c e s 3 and 7.
Examples o f t y p i c a l commercial i n s t a l l a t i o n s
f o r UV r a d i a t i o n p r o c e s s i n g equipment a r e d e s c r i b e d i n Table 2-5.
(9-13)
H I G H ENERGY ELECTRON RADIATION PROCESSING EQUIPMENT
Electron-beam processors a r e used c o m m e r c i a l l y t o c r o s s - l i n k polymers , i n s u l a t i o n s ,
and w i r e - c a b l e c o v e r i n g s , t a k i n g advantage o f t h e i r a b i l i t y t o p e n e t r a t e v e r y t h i c k
coatings.
The b a s i c components o r subsystems t h a t make up a high-energy e l e c t r o n
processor are a power s u p p l y (DC o r RF),
a source o f e l e c t r o n s (e.g.,
a heated w i r e
f i l a m e n t o r r i b b o n ) , a beam a c c e l e r a t i o n system, a vacuum chamber ( l o m 8 t o 10-
6
t o r r ) , o u t p u t windows, and s h i e l d i n g o r housing r e q u i r e d t o c o n t a i n t h e X-rays
generated b y t h e high-energy e l e c t r o n s i m p i n g i n g on t h e s u r f a c e e n c l o s i n g t h e e l e c t r o n a c c e l e r a t o r ( F i g u r e 2-14).
(14)
-
A c c e l e r a t o r s can be c l a s s i f i e d according
t o t h e i r r a t e d t e r m i n a l v o l t a g e power s u p p l y requirements which range i n v a l u e f r o m
0.25-30 MeV.
The LINAC a c c e l e r a t o r and s e v e r a l e l e c t r o s t a t i c a c c e l e r a t o r systems
(Van de Graaf , P e l l e t r o n , L a d d e r t r o n ) r e q u i r e v e r y h i g h t e r m i n a l v o l t a g e power
s u p p l y o p e r a t i n g p o t e n t i a l s (minimum 4 MeV f o r t h e LINAC; between 0.3 t o 30 MeV
for electrostatic accelerators).
However, these devices are n o t n o r m a l l y used f o r
2-1 5
Thermionic
Cathode
Lamp
--
I
.
Starting Switch
Ballast
A-C Supply
Power Supply Circuit for a
Low Pressure Mercury Arc
Capacitor
Transformer
Power Supply for a
Medium Pressure Arc
b
R
e
Capacitor
/
C
Transformer
t
i
f
i
e
r
Lamp
V
Spark Gap
Power Supply for a
Flash Lamp
F i g u r e 2-11.
UV/Vis L i g h t Source Power S u p p l i e s
2-1 6
(7)
I
1
mE
e
E
E
O 0 b
e
E
E
f
E
E
d
d
cv
.-*wC
c
5
a
2-1 7
Table 2-3
UV LAMP OPERATING CHARACTERISTICS
Low Pressure
Mercury
Medium Pressure
Discharge Mercury
(E)
Microwave
Energized
Mercury
Lamp Temp.
coo 1
Lamp Power
1 - 10 Watts/In. 100 - 400 Watts/In. 300 Watts/In.
Arc Lengths
10
Bulb Shapes
Li near,
Circular
-
High
High
75 Inches
1-1/2
- 77 Inches
Linear , Curved
10 Inches
Linear
Flash Xenon
Moderate
(Water Cooled)
.1 to 10 MegaWatts Peak
Power
- 30 Inches
Linear ,
Ci rcu 1 ar ,
.6
Helical
Re 1 at ive
System Costs
Low
Input Power
Lamp Warranty
1 - 10 Watts/In. 110 - 440 Watts/In. 550 Watts/In.
17,500 Hours
1,000 Hours
3,000 Hours
--
254
365, 436, 546,
580
365, 636,
546, 580
450
Spectral
Variations
None
Moderate
Extensive
Limited
Spectral
E ff i c i ency
Excel lent
Good
Very Good
Poor
Radiant
Efficiency
Very Good
Good
Fair
Poor
Overall
Efficienty
Fair
Good
Good
Poor
Practical
Limits
Low Intensity
None
Limited Sizes
Low Efficiency
$200
Under $2,000
Moderate
High
High
1,000 Hours
M a j o r Output
Wavelengths
(“1
Total
System Cost
2-1 8
$3 to 7,000
$4,000
T a b l e 2-4
OPERATIONAL CHARACTER1 S T I CS OF ELECTRODE AND
ELECTRODELESS MEDIUM PRESSURE MERCURY ARC LAMP (8)
-
-
Conventional
6"
LENGTH
POWER
-
-
7"
'
E l ectrodel ess
Any l e n g t h i n modular 10" segments
100, 200, 300 W/in
300 W/in
Discrete steps
30-300 W/in stepped o r continuously
var iab1e
6600 W, 460/230 V
5200 W, 240 V
Guaranteed
1000 hours
3000 hours
Expected
1000 h r UV output
II
300011 II
6000 'I 'I
lo
2000 hours
85%
52%
10%
6000 hours
97%
92%
86%
INPUT POWER TO SYSTEM
LIFETIME
Effect o f starts
None
No more than 250
i n guarantee
SPECTRAL OUTPUT
Lamp I n p u t
output: uv
Visible
Infrared
Convected
200 W/in
34
56
100
10
300 W/in
97
75
55
73
Limited
Unlimited
-
10 - 100%
1000 3000 h r s
None
None
DOPED LAMPS
Avai l a b i 1 i t y
Relative spectral
shifts
Typical l i f e t i m e s
Length l i m i t a t i o n s
B a l l a s t changes
10
500
20%
1000 h r s
Usually
Usually
-
-
ON/OFF
Cold s t a r t u p time
Cool-down r e s t a r t t i m e
45 sec - 3 min
2 - 10 min o r
45 sec
2
-
4 sec
10 sec
STANDBY
Power l e v e l
Shutters
50%
Typically
0
No
No
Yes
Yes
Yes
Yes
COOLING 81 UTILITIES
Positive a i r
Negative a i r
Water
Compressed a i r
Nitrogen
REFLECTOR GEOMETRY
No
No.
No
Yes
Yes
E l l i p t i c a l and
Unfocussed
E l l i p t i c a l and
Unf ocussed
SPACE REQUIREMENTS
Height
Width
4 - 6"
6 - 10"
12
8"
2-1 9
18"
Air
(5) H20
Air
)
H20
UV Source: Linear Electrode Lamp (200/300 w/in)
Power Supply: 1.5 KV AC > 90% Efficiency
Reflector (Parabolic or Elliptical)
Energy Profile
Cooling (Air, H20)
Housing: Radiation Containment
Conveyor Bed
Negative
Air Cooling
Positive
Air Cooling
Power Cable
Reflector
Controller
Radiator
(10” long
16” tall
9“ wide)
-
Exhaust
Lamp’
Electrodeless Lamp Curing System
(Fusion Systems)
Figure 2-13.
Commercial UV Processor Units
2-20
(8)
Table 2-5
UV CURING EQUIPMENT
UV
Curing Device
Descriptions
Small (15" maximum); 1 or 2 lamps
(9)
End Use Applications
Laboratory and in-plant ink, coating and
adhesive testi ng.
Production curing of electronic components;
erasing of EPROM computer chips and curing
of areas with point source lamps.
Medium (18" and up); multiple
lamp systems
Heavy substrates, multiple lamp systems for
curing glass, metal and wood: for curing in
PC boards and photoresist systems for the
electronics industry and multiple lamp systems for paper and plastics (screen, letterpress offset or flexoprinted).
Large multichamber UV drying ovens
(80" wide to 60' long with as many
as 12 rows of lamps)
Floor tile, electronics, special textured
coatings, abrasion resistant coatings
and combinations o f U V - I R for the graphic
arts industry on paper, board or glass
substrates.
UV
lamps mounted over belts or
rollers so that the substrate is
cured and stacked
Sheet paper or board stock; screen printing
and circuit board manufacture.
38" wide in-press sheet curing UV
systems; narrow and wide continuous
web UV curing systems--flex0 and
letterpress assemblies (UV lamps
can be used 80" in length)
Graphics art industry--sheetfed multicolor
presses, wet-on-wet printing of UV clear
coatings over UV or solvent-based net offset inks--tag and label products and wallpaper or linoleum substrates.
Multiple lamps housing assemblies
UV
curing of three-dimensional objects such
as cups, lids, wire, optical fibers, tubes,
boards containing attached components
(compound coatings), partial and fully
assembled furniture, tabletops, and
s he1 vi ng
PC
.
2-21
Power
I
U
9
Vacuum
-
Shielding
I
output
Window
Figure 2-14. General Schematic o f A High Energy Electron Beam
Processing Unit (14)
2- 22
r a d i a t i o n processing o f polymer m a t e r i a l s .
I n d u s t r i a l machines h a v i n g t e r m i n a l
v o l t a g e power s u p p l y energy ranges between 0.3 t o 4 MeV a r e t y p i c a l l y r e p r e s e n t e d
b y t h e insulated-core-transformer ( I C T ) and t h e Dynamitron ( F i g u r e 2-15).
Conven-
t i o n a l l y b o t h machines operate w i t h a maximum l i n e a r c u r r e n t d e n s i t y o f about 50
mA/m;
t h e energy c o n v e r s i o n e f f i c i e n c y f o r e i t h e r d e v i c e i s about 70% w i t h t h e
o v e r a l l system e f f i c i e n c y b e i n g about 40 t o 50%.
Both t h e Dynamitron and t h e ICT
power s u p p l i e s can be u t i l i z e d i n a scanned beam c o n f i g u r a t i o n as shown i n F i g u r e
2-16.
I n a scanned beam c o n f i g u r a t i o n t h e power s u p p l y i n c r e a s e s and r e c t i f i e s t h e
1ine c u r r e n t and t h e a c c e l e r a t o r tube generates and focuses t h e beam ( a p p r o x i m a t e l y
1 cm i n diameter a t t h e window) and c o n t r o l s t h e e l e c t r o n scanning process. The
beam i s produced when h i g h v o l t a g e energizes a t u n g s t e n f i l a m e n t t h e r e b y c a u s i n g
e l e c t r o n s t o be produced a t v e r y h i g h r a t e s .
.
These f a s t e l e c t r o n s a r e c o n c e n t r a t e d
t o f o r m a high-energy beam and are a c c e l e r a t e d t o f u l l v e l o c i t y i n s i d e t h e e l e c t r o n
gun.
Electromagnets on t h e s i d e s o f t h e a c c e l e r a t o r tube a l l o w d e f l e c t i o n o r scan-
n i n g o f t h e beam as i n a t e l e v i s i o n tube.
61-183 cm t o 10-15 cm, r e s p e c t i v e l y .
metal f o i l
, usually
Scanning w i d t h s and depths v a r y f r o m
The scanner opening i s covered w i t h a t h i n
t i t a n i u m , t h a t a l l o w s passage o f e l e c t r o n s b u t m a i n t a i n s t h e
h i g h vacuum r e q u i r e d f o r h i g h f r e e - p a t h l e n g t h s .
C h a r a c t e r i s t i c power, c u r r e n t ,
and dose r a t e s o f a c c e l e r a t o r s are 200-500 kV, 25-200 mA, and 10-100 kGy/s (1-10
Mrad/s )
. (15-17
High v o l t a g e scanned e l e c t r o n processors have s e v e r a l disadvantages.
severe of these i s t h e l a r g e areas which must be s h i e l d e d .
The most
Any s u r f a c e e n c l o s i n g
t h e e l e c t r o n a c c e l e r a t o r scanner a c t s as a source o f X-rays generated b y e l e c t r o n s
which a r e s c a t t e r e d t o t h e w a l l , and these emissions are along t h e e n t i r e l e n g t h o f
t h e system.
Another disadvantage i s t h e l a r g e space requirement f o r housing t h e
equipment. (18)
I n a l i n e a r o r p l a n a r cathode system (developed by Energy Sciences) t h e t e r m i n a l
energy requirements a r e about 150 t o 300 kV b u t t h e beam area can be 1000 cm2 and
t h e l i n e a r c u r r e n t d e n s i t y can be as g r e a t as 260 mA/m.
Operation o f a l i n e a r
cathode processor i s through a h i g h - v o l t a g e (150 kV) e l e c t r o n tube t h a t p r o v i d e s a
c o n t i n u o u s s t r i p o f e n e r g e t i c e l e c t r o n s f r o m a l i n e a r f i l a m e n t o r cathode, which i s
on t h e a x i s o f symmetry o f t h e system.
The c y l i n d r i c a l e l e c t r o n gun shapes and
processes t h e e l e c t r o n system i n a g r i d - c o n t r o l l e d s t r u c t u r e .
The stream i s t h e n
a c c e l e r a t e d across a vacuum gap t o a metal window where i t emerges d i r e c t l y i n t o
a i r and t r a v e l s o n t o t h e p r o d u c t .
I n t h i s t y p e of l i n e a r processor, t h e s h i e l d i n g
i s c l a d d i r e c t l y t o t h e t u b e housing.
Housing space i s r e l a t i v e l y s m a l l , s i n c e a
s h i e l d e d tube 25 cm i n diameter r e p l a c e s t h e 3-m h i g h s t r u c t u r e r e q u i r e d f o r t h e
2-23
30
20
L
I
N
A
C
10
9
8
7
6
5
4
3
2
MeV
E
L
E
C
T
R
0
S
T
A
T
I
C
D
Y
N
A
M
I
1
0.9
0.8
0.7
0.6
0.5
T
R
0
N
I
C
T
00
0.4
0.3
Cathode
0.2
0.1
I
High Potential 2
Medium Potential1
Low Potential1
Accelerators
Figure 2-1 5.
H i gh and Low Energy El ectron Processor Power Suppl i e s
2- 24
(1 5,16,17)
Shielding
I
I
/
Electron Gun
/ Filament
'
Acceleration
Section
II
1
'
1
1
Scanning Coils
Vacuum
Scanning Housing
I
I
I
I'
\ \
\
\
I
1
I
'
Figure 2-1 6 .
Metal Foil Window
I
t
Scanned Electron Beam Accelerator System
2-25
(E)
scanned electron-beam apparatus.
The e l e c t r o c u r t a i n has a more f l e x i b l e geometry
and can be adapted r e a d i l y t o many d i f f e r e n t types o f c u r i n g a p p l i c a t i o n s ( F i g u r e
2-17).
(19)
Another design f e a t u r e o f t h e p l a n a r cathode processor i s t h e a b i l i t y
t o combine two a c c e l e r a t i o n s e c t i o n s w i t h one o r two separate power s u p p l i e s f o r
i n c r e a s e d beam i n t e n s i t y values i n t h e range o f 400 mA/m ( F i g u r e 2-18). (20)
A d i f f e r e n t t y p e o f m u l t i p l e p l a n a r cathode processor has been developed by
R a d i a t i o n Polymer C o r p o r a t i o n .
I n t h i s equipment t h e cathode s t r u c t u r e i s com-
p l e t e l y modular such t h a t i t s l e n g t h can be e a s i l y i n c r e a s e d t o accommodate t h e
s i z e requirements o f a p r o d u c t l i n e w h i l e m a i n t a i n i n g i t s w i d t h p r o p o r t i o n cons t r a i n t s i n o r d e r t o meet t h e machine's requirements f o r an acceptable window c u r rent density profile.
The cathode s t r u c t u r e i s a "screen" tube t y p e c o n s t r u c t i o n
c o n s i s t i n g o f a s e r i e s o f modular t r i o d e s arranged i n a l i n e a r a r r a y as shown i n
F i g u r e 2-19.
T h i s modular cathode c o n s t r u c t i o n a l l o w s f o r broad-beam (250 cm wide) p r o c e s s i n g
of m a t e r i a l s w i t h powers o f 30 kGy ( 3 Mrad) a t 300 m/min. and l i n e a r c u r r e n t densi t i e s o f 262 mA/m.
The system a l s o i n c l u d e s i n t e g r a t e d s h i e l d i n g c a p a b i l i t i e s
s i m i l a r t o t h o s e d e s c r i b e d f o r Energy S c i e n c e ' s p l a n a r cathode equipment. ( 21)
A h i s t o r i c a l growth r e p r e s e n t a t i o n f o r h i g h energy p r o c e s s i n g equipment development
and u t i l i z a t i o n i s shown i n F i g u r e 2-20 and a g e n e r a l i z e d comparison between swept
beam and p l a n a r cathode h i g h energy e l e c t r o n p r o c e s s i n g equipment i s d e s c r i b e d i n
F i g u r e 2-21 and Table 2-6.
(22)
Table 2-6
COMPARISONS BETWEEN PLANAR CATHODE AND SWEPT BEAM
HIGH ENERGY ELECTRON PROCESSING EQUIPMENT (18,21,22 1
P l a n a r Cathode
Swept Beam
Scan System
No
Yes
Beam Shape
Rec t angu 1a r
Swept s p o t
Energy Dose Rate
Low
High
C omp ac t S iz e
Yes
No
S h i e 1d i n g
Less
Greater
Housing Vol ume
Less
Greater
Cmplexity
Less
Operating Voltage
200 KeV
Pene t r a t ion
10 m i l s
2- 26
Greater
200 KeV-1 MeV
200 m i l s
I
\
Chamber
Vacuum
High Voltage
Power Supply
L
:
Structure Terminal
Electron Gun
~
\
Figure 2-17.
Metallic Foil Window
(Anode)
Energy Science Planar Cathode Electron Curtain Processor
2-27
(18,19)
..
C
C
b
CI
El
v
c,
S
W
E.
*r
3
0-
W
E
W
m
S
0
L
c,
u
W
7
W
W
S
0
N
cn
S
.r
m
v)
W
u
0
L
a
-0
a,
-0
E
W
c,
x
w
a3
I
N
W
L
3
cn
.r
LL
2- 28
Figure 2-19. Radiation Polymer Corporation's Modular Planar Cathode
Processor (21)
2-29
-n
a.
a
c
5
rD
Beam Current (mA/m)
N
I
h)
N
0
0
N
I
w
0
I
0
0
P
0
VI
0
ln4atoo
0 0 0 0 0
h)
0
0
0
0
0
P U I
0
0
0
0
= Area of Beam
= Width of Product
= Effective Width of Cure Zone
V = Velocity of Traversal of Cure Zone
Where: A
W
.
Comparison Between Planar Cathode and Swept Electron Beam
Figure 2-21
Processing Units (21,22)
2-31
PLASMA RADIATION PROCESSING EQUIPMENT
P 1asma r a d i a t i o n sources i n commercial a p p l i c a t i o n s f a l l i n t o t h r e e c a t e g o r i e s
therma
T herma
, cold,
and h y b r i d plasma systems.
(23)
plasmas a r e produced by gas arcs under atmospheric p r e s s u r e i n t h e r e g on
5,000 t o 50,000 K.
The k i n e t i c energies o f t h e a r c ' s gas molecules, i o n s , and
electrons are i n e q u i l i b r i u m conditions.
A d i s c h a r g e i s produced t h a t r e q u i r e s a
h i g h v o l t a g e between f i x e d e l e c t r o d e s f o r i n i t i a t i o n b u t t h a t can be m a i n t a i n e d
( a f t e r t h e i n i t i a t i o n process) a t low v o l t a g e s b y a power s u p p l y w i t h low i n t e r n a l
r e s istance
.
Cold plasmas a r e produced b y glow discharges, such as those found i n neon s i g n s .
The gaseous i o n s and n e u t r a l gas molecules have temperature ranges between ambient
and a few hundred degrees, whereas t h e e l e c t r o n s have v e r y h i g h temperature values
and are n o t under thermal e q u i l i b r i u m c o n d i t i o n s .
A d i s c h a r g e t h a t i s produced
i n a gas such as argon a t low pressures (1 mm Hg) can be s u s t a i n e d w i t h as l i t t l e
as 300 V w i t h no l o s s i n e f f i c i e n c y f o r e f f e c t i n g polymer s u r f a c e - t r e a t m e n t m o d i f i c a t i o n s o r p r o d u c i n g c o a t i n g s on t h e s u r f a c e s o f metal or nonmetal s u b s t r a t e materials.
The power s u p p l y f o r t h i s t y p e o f plasma can be designed around dc, low
frequency, r a d i o - f r e q u e n c y , o r microwave- frequency g e n e r a t o r systems; t h e equipment used i n t h i s technology i s e i t h e r e x t e r n a l l y coupled ( c a p a c i t i v e l y o r induct i v e l y ) o r i n t e r n a l l y coupled ( c a p a c i t i v e l y o r r e s i s t i v e l y ) as d e s c r i b e d i n F i g u r e s
2-22 and 2-23.
I n t h e e x t e r n a l l y coupled apparatus a c o i l , or two p a r a l l e l p l a t e
e l e c t r o d e s , a r e p l a c e d around t h e o u t s i d e o f t h e q u a r t z o r g l a s s vacuum chamber.
glow d i s c h a r g e i s formed i n s i d e t h e chamber when radio-frequency
t o the c o i l or external electrodes.
A
power i s a p p l i e d
The advantage o f t h i s system over t h e i n t e r n a l
e l e c t r o d e system i s t h a t c o n t a m i n a t i o n o f t h e processed p r o d u c t b y e l e c t r o d e degrad a t i o n i s avoided. (24,251
I n l a r g e - s c a l e commercial a p p l i c a t i o n s o f plasma p r o c e s s i n g t e c h n o l o g y i t i s o f t e n
r e q u i r e d t o t r e a t o r c o a t sheet m a t e r i a l s i n t h e f o r m of a continuous web.
The
s u p p l y and take-up r e e l s f o r t h i s process can be o u t s i d e o f t h e plasma p r o c e s s i n g
chamber as shown i n F i g u r e 2-24.
I t i s a l s o p o s s i b l e t o have b o t h r e e l s i n s i d e t h e
vacuum chamber as shown i n F i g u r e 2-25.
The r e l a t i v e economics f o r p r o c e s s i n g
m a t e r i a l s i n a plasma apparatus w i l l be discussed l a t e r . 2
(61The t h i r d t y p e o f plasma, h y b r i d plasma, i s between c o l d and thermal plasmas and i s
d e f i n e d as having numerous small thermal sparks , u n i f o r m l y d i s t r i b u t e d throughout
l a r g e volumes o f n o n i o n i z e d gas molecules, t h u s p r o d u c i n g a r e l a t i v e l y low average
2-32
Reactor Diagram
Leak Valve
RF Coil
Reactor
To Argon
Purge
Trap
System
I
Roughing
++
Valves
I F 0 Ring Joint
P
Diffusion Pump
Pressure Gauge
Figure 2-22.
Tubular Reactor for P1 asma Polymerization
2-33
(24,25)
a
2-34
Treatment Gas or
Monomer Supply
RF Power Supply
Matching Network
Flow Transducer
Supply Reel
Figure 2-24.
Take-U p-Reel
Air-to-Air Plasma Processing System (26)
-
2-35
Figure 2-25. Example o f Plasma Processing w i t h Supply and
Take-up Rolls w i t h i n the Vacuum Chamber
2-36
temperature of the plasma s t a t e . Corona and ozone generators are associated with
t h i s type o f plasma, which is produced by a high impedance power supply or electrode arrangement. High voltages are required t o maintain i t s discharge charact e r i s t i c s (60-10,000 Hz a t several thousand v o l t s ) . These types of plasmas are
most often used t o surface t r e a t p l a s t i c films and parts f o r improved adhesive
bonding or improved p r i n t a b i l i t y ( p r i n t i n g ink r e c e p t i v i t y ) . (27-1
2-37
Section 3
RADIATION PROCESSING CHEMISTRY AND MATERIALS
R a d i a t i o n p r o c e s s i n g o f m a t e r i a l s i s a technology based on t h e f o l l o w i n g :
Chemical r e a c t i o n s o f smal 1 monomer o r oligomer components
(molecular weight, ca 100-1,000) t o form l a r g e polymer
components ( m o l e c u l a r weight, ca 1,000-25,000
infinite).
0
-
0
Small monomer-oligomer components combining t o g e t h e r w i t h l a r g e
preformed polymer components.
0
Connecting l a r g e polymer components t o g e t h e r .
0
Changing t h e s u r f a c e c h e m i s t r y o f l a r g e polymer components f o r
improved chemical o r p h y s i c a l p r o p e r t i e s ( F i g u r e 3-1).
The o v e r a l
chemi s t r y o r chemical r e a c t i o n s o f m a t e r i a l s a s s o c i a t e d w i t h t h i s t e c h -
n o l o g y can be f u r t h e r c l a s s i f i e d as thermal ( c o n v e n t i o n a l ) , UV l i g h t - i n d u c e d
( photochem c a l o r pho o p o l y m e r i z a t i o n ) , h i g h energy e l e c t r o n , and plasma
(28)
processes.
THERMAL RADIATION PROCESSING CHEMISTRY
The major commercial uses o f thermal r a d i a t i o n processes a r e s o l v e n t removal ( c o a t i n g s , i n k s , and adhesive a p p l i c a t i o n s ) and t h e e f f e c t i n g o f chemical r e a c t i o n s
between oligomers ( m u l t i f u n c t i o n a l low m o l e c u l a r weight prepolymers o r c r o s s l i n k i n g m o l e c u l e s ) and preformed s o l v e n t - s o l u b l e o r d i s p e r s i b l e h i g h m o l e c u l a r
w e i g h t polymers i n o r d e r t o c r e a t e three-dimensional network s t r u c t u r e s .
The chem-
i c a l and p h y s i c a l p r o p e r t y response c a p a b i l i t i e s o f cured f i l m s o r s t r u c t u r e s a r e
-
-
improved over t h o s e o f t h e o r i g i n a l m a t e r i a l s b e f o r e t h e thermal p r o c e s s i n g
o p e r a t ion.
(2)
polymer
Polymer
I
X
thermal energy
groups
*cross-linking
5. s i t e s
X
01 igomer
-
polymer
I
'I
sol vent
3- 1
polymer
M
R
A
D
M
A
T
W
I
P
Linear Polymer
N
M
-P
M
O
O
Crosslinked ThreeDimensional Network
Structure (Cured)
P
R
0
C
E
S
S
O
x x x
-P
M
0
P
x
= Monomer (mol wt, Ca 100-500)
= Oligomer (mol wt, Ca 200-1000)
= Polymer (mol wt, Ca 1,000-Infinite)
= Functional Group
Figure 3-1.
Radiation Processing Chemistry
3- 2
(28)
I n some a p p l i c a t i o n s (e.g.,
w i r e and c a b l e i n s u l a t i o n ) , a preformed polymer,
r u b b e r , o r elastomer can be c r o s s - l i n k e d d i r e c t l y w i t h p e r o x i d e s o r v u l c a n i z i n g
agents as w e l l as combinations o f peroxides w i t h m u l t i f u n c t i o n a l r e a c t i v e o l i g o -
-
m e r i c m a t e r i a l s t o f o r m c r o s s - l i n k e d polymer network s t r u c t u r e s .
polymer
-
+ peroxide
(1,291
g
*-I
polymer + peroxide + cross-1 inking
01 igomer
cross-1 inked
network
structure
Conventional thermal p r o c e s s i n g w i t h I R r a d i a t i o n i s m a i n l y i n v o l v e d w i t h thermof o r m i n g o r heat-bonding o f t h e r m o p l a s t i c p o l y m e r i c m a t e r i a l s .
These polymer heat--
f o r m i n g o r m e l t i n g processes u s u a l l y do n o t c u r e t h e polymer b u t o n l y cause p h y s i c a l changes and m a i n t a i n t h e o r i g i n a l polymer t h e r m o p l a s t i c c h a r a c t e r i s t i c s .
I n o r d e r t o cure, i .e.,
f o r m three-dimensional network s t r u c t u r e s t h r o u g h chemical
changes, w i t h I R r a d i a t i o n , i t i s necessary t o design a r e a c t i v e f u n c t i o n a l i t y
w i t h i n t h e polymer s t r u c t u r e so t h a t c o u p l i n g r e a c t i o n s can t a k e p l a c e between
polymer chains.
-rpolyme
c=o
CHOH
c =o
OH
I
Acid functional
group
CH\
CH
‘2
irradiation
heat
I
I
0I
y 2
I
0
I
7H2
CHOH
Epoxy f u n c t i o n a l
group
r
polymer
c r o s s 1in ked polymer
-
C e r t a i n p o l y m e r i c s t r u c t u r e s can a l s o be blended w i t h o t h e r c o r e a c t i v e polymers o r
m u l t i f u n c t i o n a l r e a c t i v e o l igomers t h a t e f f e c t c u r i n g r e a c t i o n s when exposed t o I R
radiation.
These c o r e a c t i v e polymers and c r o s s - l i n k i n g o l i g o m e r s undergo condensa-
t i o n o r a d d i t i o n , which cause network f o r m a t i o n (Table 3-1). (30-32)
3-3
Table 3-1
INFRARED OR THERMAL RADIATION PROCESSING CHEMISTRY (30,31)
Monomer, 01i gomer,
or Pol m e r
Reaction Mechani sm
Me1 ami ne 01 igomers and
hydroxyl -functional polymers
Transetherification of the melamine with
the polymer to form crossl inked polymer
network structures
Styrene monomer and unsaturated polyesters with
peroxides
Thermal destruction o f the peroxide to
produce free radical intermediates which
initiate the polymerization o f styrene
with the unsaturated polyester
Epoxy polymers and acid or
amine functional 01 igomers
or pol ymers
Acid or amine addition to the epoxy ring
followed by ring opening and polymerization into three-dimensional network
structures
B1 ocked isocyanates and
hydroxyl -functional
pol ymers
Unblocking of the isocyanate followed by
NCO addition to the polymer hydroxyl
group and curing
Air, metal catalysts and
unsaturated oil modified
polyesters
Air drying or air oxidation to form
crosslinked films
Peroxide crossl inking of
polyethy ene (direct
process)
Radical induced hydrogen abstraction
reactions leading to polymer chain
connections and crossl inking
Peroxide plus mu1 ti functional v nyl unsaturated
ol i gomer and polyethylene
Radical formation, addition propagation
and hydrogen abstraction reactions to
form crossl inked polymer structures
3-4
UV-VISIBLE LIGHT PROCESSING CHEMISTRY
The t r e a t m e n t o f p o l y m e r i c u l t r a v i o l e t ( U V ) o r v i s i b l e l i g h t r a d i a t i o n f a l l s i n t o
two c l a s s e s :
100% r e a c t i v e l i q u i d systems ( c o a t i n g s , i n k s , adhesives) and photo-
s e n s i t i v e preformed polymer s t r u c t u r e s .
I n t h i s context t h e r e are f i v e character-
i s t i c s o f UV and v i s i b l e - l i g h t energy i r r a d i a t i o n o r p h o t o c u r i n g o f l i q u i d photopolymer systems.
0
(33)
A s t a b l e l i g h t source i s r e q u i r e d , capable o f p r o d u c i n g UV and
v i s i b l e wavelengths o f l i g h t , i.e.,
near and f a r UV, 200-400 nm
t o v i s i b l e , 400-700 nm, w i t h s u f f i c i e n t power o r i n t e n s i t y t o
be c o m m e r c i a l l y f e a s i b l e .
(1)
0
A p h o t o i n i t i a t o r i s r e q u i r e d , capable o f absorbing UV and
v i s i b l e - l i g h t r a d i a t i o n a t a p p r o p r i a t e wavelengths o f energy as
e m i t t e d f r o m t h e l i g h t source (Table 3-21. (34)
-
0
A c t i v e f r e e r a d i c a l s o r a c i d i n t e r m e d i a t e s must be produced
through t h e a c t i o n of l i g h t a b s o r p t i o n b y t h e p h o t o c h e m i c a l l y
a c t i v e p h o t o i n i t i a t o r . The f r e e r a d i c a l s i n i t i a t e p o l y m e r i z a t i o n o f u n s a t u r a t e d monomers , o l igomers , and polymers; t h e
photochemically l i b e r a t e d a c i d intermediates i n i t i a t e c a t i o n i c
o r r i n g opening p o l y m e r i z a t i o n r e a c t i o n s o f epoxy f u n c t i o n a l
monomers, 01igomers, and polymers.
e
Unsaturated , h i g h b o i 1ing a c r y l ic o r m e t h a c r y l ic monomers ,
oligomers, c r o s s - l i n k i n g agents , and low m o l e c u l a r w e i g h t p o l y mers comprise t h e f l u i d , low v i s c o s i t y , l i g h t - c u r a b l e c o a t i n g
system and a r e analogous t o t h e c o a t i n g m a t e r i a l s used i n
t h e r m a l c u r i n g processes. Low m o l e c u l a r w e i g h t and h i g h molecu l a r weight epoxy r e s i n s ( c a t i o n i c c u r i n g mechanism) would
a l s o be f o r m u l a t e d i n a s i m i l a r manner as t h e u n s a t u r a t e d
m a t e r i a l s ( f r e e r a d i c a l c u r i n g mechanisms) (Table 3 - 3 ) . (33)
e
F r e e r a d i c a l i n i t i a t i o n o r c a t i o n i c r i n g opening r e a c t i o n s o f
t h e r e a c t i v e l i q u i d system and p r o p a g a t i o n i n t o a f u l l y cured,
c r o s s - l i n k e d s o l i d c o a t i n g o r f i l m . (35)
The mechanism o f c a t i o n i c c u r i n g and f r e e r a d i c a l c u r i n g i s o u t l i n e d as f o l l o w s .
F r e e R a d i c a l P h o t o c u r i n g System
p h o t o i n i t i a t o r (PI)
7>U V - V i s
PI.
l i g h t energy
i
PI. +
mu1 t i f u n c t i o n a l
unsaturated
monomers and polymers
f r e e r a d i c a l intermediate
x
three dimensional
network s t r u c t u r e
3- 5
Table 3-2
PHOTOINITIATORS USED IN ULTRAVIOLET RADIATION
CURABLE POLYMERIC MATERIALS (34)
Free Radical Photoinitiators
Cationic Photoini ti ators
0
Alkyl ethers of benzoin
0
Diazonium salts of Lewis acids
0
Benzil ketals
0
Aryl iodonium salts of Lewis acids
0
Acetophenone derivatives
0
Aryl sulfonium salts of Lewis acids
0
Ketone-amine combinations
0
Halogenated compounds
Table 3-3
MATERIALS USED IN RADIATION (UV AND EB) CURABLE COATINGS
Free Radical Curinq Mechanisms
0
Single-functional vinyl monomers
2-ethyl hexyl acrylate, styrene, N-vinylpyrrol idinone, vinyltoluene, lauryl
methacryl ate
0
Multifunctional vinyl monomers
1-6-hexanediol diacrylate, tetraethylene glycol
diacryl ate, trimethylolpropane triacryl ate,
pentaerythri to1 triacrylate
0
Unsaturated polymers
mal ei c-fumar i c acid unsaturated pol yes ters ,
acrylic copolymers containing pendant vinyl
unsaturation, epoxy acrylates, polyurethane
acrylates
Cationic Curinq Mechanisms
0
Single-functional monomers
vinyl methyl ether, lauryl epoxide
0
Mu1 ti functional epoxide monomers
diepoxides or triepoxides phenolic and
polyhydroxy a1 coho1 compounds
3-6
(a)
C a t i o n i c P h o t o c u r i n g System
>- UV-Vis
PI
acid
1 I gh t energy
acid
+
LA
mu1 t i f u n c t i o n a l
epoxy polymers
three dimensional
network s t r u c t u r e s
I n preformed polymer systems t h e d i r e c t a b s o r p t i o n o f UV o r v i s i b l e l i g h t causes
t h e polymer s u b s t r a t e s t o undergo c h a i n s c i s s i o n ( d e g r a d a t i o n ) and c r o s s - l i n k i n g .
C r o s s - l i n k i n g o r c u r i n g o f preformed p o l y m e r i c m a t e r i a l s (e.g.,
t h e r m o p l a s t i c s ) can
be markedly enhanced through use o f s p e c i a l p h o t o s e n s i t i v e molecules t h a t a r e mixed
i n t o t h e polymer m a t r i x o r t h a t c h e m i c a l l y a t t a c h t o t h e backbone o f t h e polymer
chains.
These s p e c i a l p h o t o s e n s i t i v e molecules absorb UV o r v i s i b l e l i g h t e n e r g i e s
much more e f f i c i e n t l y t h a n t h e polymer; t h e y r a p i d l y f o r m e x c i t e d s t a t e s which
undergo photochemical r e a c t i o n s , which i n t u r n f o r m r e a c t i v e f r e e - r a d i c a l intermedi a t e s t h a t e f f e c t polymer d i m e r i z a t i o n o r c r o s s - l i n k i n g .
These s p e c i a l p h o t o s e n s i -
t i v e molecules, when compounded i n t o t h e preformed polymer m a t r i x , can undergo
l i g h t - i n d u c e d r a d i c a l a b s t r a c t i o n o r i n s e r t i o n r e a c t i o n s which r e s u l t i n c o u p l i n g
(36)
o f t h e polymer c h a i n s and network f o r m a t i o n .
0
II
r
polymer-CH2-polymer t
db45Jbe n zo p hen on e
( phot osens it i ve mol ecu 1e 1
6‘B
OH
I
r-
P ol ymer - CH - po 1ymer
t
degraded and c r o s s 1in ked polymers
polymer,
polymer-CH = CH-polymer t N3RN3
/polymer
C HNHRN HC H
hv
b i s a z i de
(photosensitive molecule)
,
.
CHH
polymer
‘ k p o 1ymer
coupling reactions
3-7
S i m i l a r types o f c r o s s - l i n k i n g r e a c t i o n s a r e observed f o r polymers t o which photos e n s i t i v e molecules a r e c h e m i c a l l y attached.
polymer-r
0
po
0
I
o =CC H =CH@
-J
hv
___3
O=CCH=CH +
?jJ
I
1
po 1ymer
P
polymer
c r o s s - 1 inked polymer
polymer c o n t a i n i n g photosens t i v e
cinnamic e s t e r l i n k a g e
R a d i a t i o n c u r i n g o f polymers w i t h UV and v i s i b l e - l i g h t energies i s used w i d e l y
i n photoimaging and p h o t o r e s i s t t c h n o l o g i e s (Table 3-4). (37)
HIGH ENERGY ELECTRON PROCESSING CHEMISTRY
I n t h i s t e c h n o l o g y e l e c t r o n e n e r g i e s o f 100 eV o r l e s s a r e used t o break chemical
bonds d i r e c t l y , e n a b l i n g f o r m a t i o n o f f r e e r a d i c a l i n t e r m e d i a t e s t h a t cause p o l y m e r i z a t i o n i n i t i a t i o n o r polymer c r o s s - l i n k i n g r e a c t i o n s .
I n l i q u i d reactive poly-
mer systems t h e low m o l e c u l a r w e i g h t v i n y l u n s a t u r a t e d monomers, o l i g o m e r s , and
(43)
polymers a r e c o n v e r t e d d i r e c t l y i n t o cured o r c r o s s - l i n k e d f i l m s t r u c t u r e s .
h i g h energy
u n s a t u r a t e d monomers, oligomers, polymers
-
> i o n i c and
free radical
intermediates
c r o s s - l i n k e d polymer
structures
growing
polymer
radicals
I
R a d i a t i o n c u r i n g o f preformed polymers w i t h high-energy e l e c t r o n i o n i z i n g - r a d i a t i o n
p r o c e s s i n g equipment can r e s u l t i n chemical changes t h a t a r e a s s o c i a t e d w i t h
c r o s s - l i n k i n g and d e g r a d a t i o n r e a c t i o n mechanisms.
Cross-linking reaction
mechanisms on preformed polymer s u b s t r a t e s u s u a l l y i n v o l v e removal o f hydrogen
atoms t o f o r m a m a c r o r a d i c a l i n t e r m e d i a t e .
coup e t o f o r m a s i n g l e molecule.
M a c r o r a d i c a l i n t e r m e d i a t e s can t h e n
T h i s c o u p l i n g r e s u l t s i n an i n c r e a s e i n t h e
o r i g n a l average molecu a r w e i g h t o f t h e s t a r t i n g polymer.
3-8
Table 3-4
PHOTOCURABLE POLYMER SYSTEMS
Polymers
Remarks
poly(viny1 cinnamate)
uv- and visible light-induced photodimeriza-
References
38
tion reactions; used in negative photoresist technologies
polychalcones
photodimerization or addition reactions;
used in negative photoresist technologies
39
polysti 1 benes
photodimerization or addition reactions;
used in negative photoresist technologies
40
cyclized rubber
cross-linked with bis-azide-nitrene insertion
reactions
41
phenolic polymers and
acid functional
acrylic resins
diazide photosensitizers for 1ight-induced
hydrophobic-hydrophi1 ic reactions associated with positive photoresist technology
42
3-9
+cross-link
site
If irradiation continues, the original polymer substrate is transformed into one
gigantic molecule of infinite molecular weight with lower solvent solubility,
higher melting point, and improved physical properties over the original material.
Enhancement of cross-linking can be facilitated through the use of multifunctional
vinyl monomers or oligomers which copolymerize and propagate much more rapidly than
in a direct coupling reaction to form greater amounts of gel or cross-linked
materials at lower dose rates and shorter reaction times.
polymer
+
(CH2=CHln
-R
ioni zing
rapid gel formation
radiation
(multifunctional vinyl monomers or oligomers)
Radiation-induced degradation reactions are in direct opposition to cross-linking
or curing processes , in that the average molecular weight of the preformed polymer
decreases bec aus e of chain scission and without any subsequent recombination of its
broken ends. (44)
ionizing radiation
polymer - polymer
polymer
t
polymer
(high mol ecul ar weight )
(low molecular weight) (low molecular weight)
In order for efficient radiation curing of a polymer to take place, these degradation processes must be minimized in favor of the desired cross-linking reaction.
THIOL CURING CHEMISTRY
somewhat different cross-linking chemistry has been developed by W. R. Grace &
Co. This technology involves the free radical addition of a thiol (mercaptan) to
an olefinic double bond:
A
3-1 0
photoinitiator
high energy
electrons
+ H'
R-S'
peroxides
free radical intermediates
-
free radical initiators
RS'
+ C H =~ CHR I
RSCH~-~HRI+
H*
R S C H ~ - ~ HIR
RSCH~CH~RI
When a polyene and a polythiol are allowed to react in a similar manner, then a
cross-linked polythioether structure can develop:
=
- polyene -
SH
=
+ HS
'
-*-
SH
I
SH
S-
- - -S f
polythioether
polyene
S
I
eneySlop---
free radical
initiator
. s-
- -I $
S
S-
S
These polyene-polythiol systems can be rapidly cured by any source of free radicals
such as UV (photoinitiator or photosensitizer), EB, or peroxide (thermal 1
techniques. (30)
PLASMA PROCESSING CHEMISTRY
Microwave or radio frequencies above 1 MHz are applied to a gas under low pressure
to produce high energy electrons, ions, and neutral species (plasma) which can
interact with organic substrates in the vapor and solid state to produce a wide
variety of reactive intermediate species. The reaction processes that take place
in a plasma atmosphere are very complex, as outlined in the following
sequence: 4(51-
3-1 1
PLASMA REACTIONS
D i s s o c i a t ion
A2 t e - - 4 2 A
E l e c t r o n Attachment
A2 + e--A
Dissoc ia t ive Attachment
A, L + e--A
I on iz a t i on
P hotoemi s s ion
A b s t r a c t ion
A
Where A2
*
t e-
2-
+ At
+ e--+A2
+2e
2,
A2+A2
+ hv
A + B2-AB
-
+ B
i s e x c i t e d molecule A2.
These complex r e a c t i o n s can be used t o c o n v e r t s i m p l e o r g a n i c molecules i n t o v e r y
t h i n (0.1 t o 8 m i c r o n s ) h i g h l y c r o s s - l i n k e d f i l m s t r u c t u r e s , t o c r e a t e a c t i v e f r e e
r a d i c a l s i t e s o n t o polymer s u r f a c e s so t h a t u n s a t u r a t e d monomers may be g r a f t e d
o n t o t h e a c t i v a t e d s u b s t r a t e , and t o c h e m i c a l l y o x i d i z e o r change t h e s u r f a c e
energy c h a r a c t e r i s t i c s of t h e polymer s u b s t r a t e f o r improved adhesion bonding,
coating, or ink r e c e p t i v i t y c a p a b i l i t i e s .
(3)
Organic
molecule
very t h i n c r o s s - l i n k e d
f i l m structures
li
va!Ors
___)
Polymer g r a f t
0
P1asma
Oxygen
Polymer
-
Active s i t e s
unsaturated
vinyl
Polar f u n c t i o n a l groups
3-1 2
Section 4
AP PL I CAT IONS /MARKETS
R a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s has found widespread commercial use i n
t h e f o l l o w i n g areas:
0
0
0
0
0
0
Coatings
Printing
Adhesives
E l e c t r o n i c s / c o m m u n i c a t i ons
P l a s t i c s and r u b b e r m a t e r i a l s
Plasma p r o c e s s i n g
The advantages o f r a d i a t i o n p r o c e s s i n g polymer t e c h n o l o g i e s over t h o s e o f convent i o n a l f o s s i 1 energy-heated p r o c e s s i n g techniques i n these areas i n c l u d e :
0
Rapid d r y i n g speeds (seconds o r l e s s ) .
0
Reduction o r e l i m i n a t i o n o f o r g a n i c s o l v e n t s , thus e l i m i n a t i n g
a i r p o l l u t i o n and i n c i n e r a t i o n problems.
0
S i g n i f i c a n t r e d u c t i o n o r e l i m i n a t i o n o f f o s s i l energy-heated
d r y i n g ovens and i n c i n e r a t o r s .
0
Coating o f h e a t - s e n s i t i v e m a t e r i a l s ( p l a s t i c s I .
0
Increased production r a t e s .
0
More e f f i c i e n t use o f p o l y m e r i c c o a t i n g m a t e r i a l s because o f
less p e n e t r a t i o n o f f l o w i n g m a t e r i a l i n t o s u b s t r a t e s .
0
Savings i n space o f a p p l i c a t i o n equipment.
0
Manufacture o f p r o d u c t s w i t h h i g h value-added p r o p e r t i e s .
0
Development o f p r o d u c t s t h a t cannot be manufactured by any
o t h e r p r o c e s s i n g technique.
Each o f these advantages w i l l become apparent i n t h e f o l l o w i n g d i s c u s s i o n s on i n d i v i d u a l a p p l i c a t i o n o r market areas a s s o c i a t e d w i t h c u r r e n t and f u t u r e r a d i a t i o n
p r o c e s s i n g techno1 o g i es
.
4-1
COATINGS
The coatings industry comprises the manufacture, sale, and use of clear and pigmented finishes which protect, decorate, and provide functional properties to a
wide variety of surfaces and objects. The product line for this industry can be
divided into three general categories: trade sales, industrial finishes, and
special -purpose coatings. Trade sales coatings are formulated for normal environmental conditions and find general applications on new and existing residential or
commercial building structures. Industrial finishes are usually formulated for
original equipment manufacture (OEM) and can be applied to products as part of the
manufacturing process. Special purpose coatings are designed for field applications, such as refinishing, or for extreme environmental stress conditions, such as
high temperature and corrosion. A generalized product line and product use description for this industry is shown in Table 4-1.
Radiation processing of coating materials is almost exclusively associated with the
industrial finishing market area; major emphasis is on wood finishing, metal coatings ,or decoration, and paper or plastic film coatings, with limited use in wire
and automotive applications. (4 7 ) Radiation curable coatings offer several advantages over conventional thermally converted solvent-based coatings systems. In
conventional thermal coatings technology a polymer and reactive cross-linking 01 igomer is dissolved in a nonreactive diluent solvent. The ratio o f solven to
polymer-cross-linking oligomer is usually 50 to 60% of the total coating system
This low viscosity liquid composition is then applied to a substrate and baked in a
gas-fired oven which removes the ,solvent and sets the polymer cross-link ng oligomer into a solid three-dimensional cross-linked network or finished coat ng. This
process is energy intensive, since most of the thermal input energy goes to heat
the substrate and remove the nonreactive di 1 uent sol vent. Additional thermal
energy is also required to activate the cross-linking reaction of the polymer with
the cross-linking oligomer in order to effect cure. In many cases the substrate is
heat or moisture sensitive and a thermally cured coating operation causes
shrinkage-warpage or dehumidification of the substrate which requires an additional
manufacturing step to produce a usable finished product. The nonreactive diluent
solvent used in conventional coatings technology usually is vented into the atmosphere (which causes pollution), burned, or recycled to make up part o f the thermal
energy of the oven used to cure the coating system (Figure 4-1).
.
In radiation curable coatings a reactive polymer and coreactive cross-linking oligomer are dissolved in a completely coreactive diluent solvent. This mixture is
applied in a similar manner as a conventional thermally cured coating but is cured
4- 2
Table 4-1
COATINGS INDUSTRY - PAINTS AND ALLIED PRODUCTS
(SIC 28500-005) (47)
Use
-
Product Type
Trade sales
(architectural coatings) (TS)
(SIC 28510-005)
"D0-i t-yoursel f", over-the-counter
sales
Exterior solventborne
Exterior waterborne
Interior solventborne
Interior waterborne
Architectural lacquers
'Industrial finishes
(product coatings , OEM;
chemical coatings,
factory appl led) (IF)
(SIC 28520-005)
Automotive finishes (primers,
sealers, topcoats)
Truck and bus finishes
Other transportation finishes
e.g., aircraft, railroad, etc.
Marine coatings , including
off-shore structures
Appliance finishes
Wood furniture and fixture finishes
Wood and composition board flat
stock finishes
Sheet, strip, and coil coatings on
metals
Metal decorating, e.g., can,
container, and closure coatings
Machinery and equipment finishes
Metal furniture and fixture
coatings
Paper and paperboard coatings
Coatings for plastic shapes and
films, e.g., packaging
Insulating varnishes
Magnet wire coatings
Magnetic tape coatings
Special-purpose coatings (SPC)
(SIC 28529-005)
Industrial maintenance paints
--interior, exterior
Metallic paints, e.g., aluminum,
zinc, bronze, etc.
Traffic paints
Automobile and truck refinish
coati ngs
Machinery refinish coatings
Marine refinish coatings
Aerosol paints and clears
Roof coatings
Fire-retardant paints
Multicolor paints
4-3
.
,
d
Reclaimed
Recycled or Burned
I
50% Solvent
Diluent
50% Polymer and
Crosslinking
Oligomer
I
t
1
Total Solvent
Removal
Polymer and
Thermal
Thermal
Energy
I
Substrate
I
I
Burned or Vented Into
Atmosphere (Pollution)
I
l
Cured film
Substrate
4
Substrate
Substrate
.!
Heat Removed from
Substrate
Conventional Thermally Cured Coating System
Reactive Solvent
Reactive Polymer
Reactive Crosslinking
Oligomer
J
Electrical or
Cured Film
t
Light Energy
i
Substrate
6
Substrate
L
Finished Product
Radiation Curable Coating Systems
.
Comparison between Conventional and R a d i a t i o n Curable C o a t i n g
F i g u r e 4-1
Technologies (28)
4-4
v i a e l e c t r i c a l or l i g h t energy processes and does n o t r e q u i r e d i r e c t thermal exp e n d i t u r e o f energy.
Since t h e r a d i a t i o n c u r a b l e c o a t i n g s a r e 100% r e a c t i v e t h e r e
a r e no v o l a t i l e s o l v e n t losses, and t h e l i q u i d c o a t i n g s u p p l i e d t o t h e s u b s t r a t e i s
t o t a l l y converted i n t o a s o l i d c r o s s - l i n k e d f i l m .
Since t h e r e a r e e s s e n t i a l l y no
v o l a t i l e emissions a s s o c i a t e d w i t h t h e c o n v e r s i o n process, r a d i a t i o n c u r a b l e c o a t i n g s a r e p o l l u t i o n f r e e and are n o t energy i n t e n s i v e processes.
Another advantage
o f r a d i a t i o n c u r a b l e c o a t i n g s i s t h a t i n t h e c u r i n g process e l e c t r i c a l o r l i g h t
energy i s absorbed o n l y b y t h e c o a t i n g and i s n o t wasted i n h e a t i n g t h e s u b s t r a t e , as i n t h e case w i t h c o n v e n t i o n a l t h e r m a l l y cured c o a t i n g systems.
This e f f i c i e n t
use of energy a l l o w s r a d i a t i o n c u r a b l e c o a t i n g s t o be a p p l i e d and processed on h e a t
s e n s i t i v e substrates, r e s u l t i n g i n f i n i s h e d products r e q u i r i n g r e l a t i v e l y simple
m a n u f a c t u r i n g o p e r a t i o n s ( F i g u r e 4-1).
(28)
-
Several major a p p l i c a t i o n areas f o r r a d i a t i o n c u r a b l e c o a t i n g s a r e discussed i n t h e
following sections.
Wood F i n i s h i n g s
The wood f i n i s h i n g i n d u s t r y can be r o u g h l y d i v i d e d i n t o wood f u r n i t u r e and f i x t u r e
f i n i s h e s ( t h r e e - d i m e n s i o n a l c o a t i n g processes) and wood o r c o m p o s i t i o n board ( p a r t i c l e board) f l a t s t o c k f i n i s h e s f o r use i n t h e manufacture o f d e c o r a t i v e panels o r
furniture.
The t r a d i t i o n a l method o f f i n i s h i n g these p r o d u c t s i s through f o r c e d h o t a i r o r
i n f r a r e d d r y i n g oven thermal t r e a t m e n t s o f v o l a t i l e s o l v e n t or water-based c o a t i n g
materials.
A t t h e p r e s e n t t i m e t h e major i n t e r e s t o f non-IR r a d i a t i o n p r o c e s s i n g
(UV and EB 100% r e a c t i v e c o a t i n g systems) i s i n f l a t s t o c k m a t e r i a l s ; a f u t u r e
t r e n d i s m o d i f i c a t i o n o f these systems f o r three-dimensional c o a t i n g
a p p l i c a t i o n s . (48-52)
Two systems have been developed f o r f i n i s h i n g o f f l a t s t o c k f o r f u r n i t u r e o r
paneling.
The r e q u i r e m e n t s f o r these c o a t i n g / i n k / a d h e s i v e systems a r e as f o l l o w s :
Wet System
Dry System
F i l l e r coating
Base c o a t
Grain p r i n t ink or
1ami n a t ion w i t h wood veneer
Top c o a t
F i l l e r coating
L a m i n a t i on adhesive
D e c o r a t i v e paper, p o l y s t y r e n e (PST) o r p o l y v i n y l c h l o r i d e (PVC) f i l m
Top c o a t
4-5
Wet f i n i s h i n g i n v o l v e s d i r e c t a p p l i c a t i o n and c u r i n g o f l i q u i d s e a l e r s , varnishes,
and p a i n t s ; d r y f i n i s h i n g i n v o l v e s a p p l i c a t i o n o f a p r e f i n i s h e d d e c o r a t i v e paper o r
52)
p l a s t i c f i l m t o t h e board s u r f a c e . (-
A p i c t o r i a l diagram f o r each system and
t h e i n d i v i d u a l c o a t i n g f u n c t i o n s i s shown i n F i g u r e 4-2.
A t y p i c a l r a d i a t i o n proc e s s i n g wood f i n i s h i n g l i n e i s d e s c r i b e d i n F i g u r e s 4-3 and 4-4. (50)
A summary
o f t h e c o a t i n g c h e m i s t r y a s s o c i a t e d w i t h thermal o r I R , UV/EB polymer m a t e r i a l s f o r
t h e wood f i n i s h i n g i n d u s t r y i s d e s c r i b e d i n Table 4-2.
The advantage o f u s i n g UV/EB r a d i a t i o n processing t e c h n o l o g i e s o v e r I R o r convent i o n a l thermal c u r e systems i s t h a t t h e r e s u l t a n t p r o d u c t can be more r e a d i l y manuf a c t u r e d ; i n some cases a s u p e r i o r p r o d u c t can o n l y be achieved t h r o u g h t h e use o f
low-temperature high-energy c u r i n g methods.
I n conventional thermal c u r i n g coating
systems t h e board i s a l s o heated and subsequently d r i e d o u t , which r e q u i r e s c o o l i n g
and sometimes r e h u m i d i f i c a t i o n b e f o r e s h i p p i n g t o a f u r n i t u r e m a n u f a c t u r e r .
With
UV/EB c u r i n g t h e board i s f i n i s h e d e s s e n t i a l l y a t ambient temperature w i t h o u t a
major loss o f m o i s t u r e c o n t e n t .
Hence, t h e s u b s t r a t e can be processed and shipped
i m m e d i a t e l y t o t h e f u r n i t u r e manufacturer.
Another advantage t o low thermal energy
c o a t i n g c u r i n g processes i s t h e i r a b i l i t y t o f i n i s h heat s e n s i t i v e s u b s t r a t e s such
as p l a s t i c s , paper, o r p o l y v i n y l c h l o r i d e ( P V C ) v i n y l f i l m s .
t h e r e a r e a p p r o x i m a t e l y 100 U.S.
A t t h e present time
wood f i n i s h i n g o r m a n u f a c t u r i n g companies u s i n g UV
l i g h t c u r a b l e c o a t i n g s and o n l y two o r t h r e e U.S.
companies u s i n g EB p r o c e s s i n g
equipment f o r manufacture o f h i g h performance low p r e s s u r e l a m i n a t e f i n i s h e d wood
products.
The reasons f o r t h i s d i v i s i o n i n r a d i a t i o n p r o c e s s i n g u t i l i z a t i o n a r e
p r o d u c t performance c o n s t r a i n t s and economics.
I n f r a r e d c u r i n g o r o t h e r forms o f
thermal c u r i n g o f c o a t i n g s a r e s t i l l w i d e l y p r a c t i c e d by t h e wood i n d u s t r y .
How-
ever, UV p r o c e s s i n g can o f f e r s e v e r a l major advantages which w i l l be discussed i n
t h e c o s t comparisons s e c t i o n o f t h i s r e p o r t .
I n cases where o n l y a v e r y s p e c i a l
p r o d u c t i s produced, such as h e a v i l y pigmented panels o r l o w p r e s s u r e l a m i n a t e s ,
t h e i n i t i a l h i g h c o s t o f EB processor equipment can be j u s t i f i e d .
A t y p i c a l EB
wood f i n i s h i n g l i n e i s shown i n F i g u r e 4-5 and EB versus thermal c u r e f i n i s h e d
p r o d u c t performance comparisons a r e shown i n Table 4-3.
(50,521
Metal D e c o r a t i v e Coatings
The metal d e c o r a t i n g i n d u s t r y uses a wide v a r i e t y o f polymer systems t o c o a t metal
cans, crowns, c l o s u r e s , c o l l a p s i b l e tubes, and p r e f i n i s h e d metal i n t h e f o r m o f
coils.
It also includes decorative f i n i s h e s applied by p r i n t i n g techniques ( l i t h -
ography and s i 1k-screen
on v a r i o u s metal s u b s t r a t e s .
The t r a d i t i o n a l method o f
f i n i s h i n g these p r o d u c t s i s u s u a l l y through g a s - f i r e d oven thermal t r e a t m e n t o f
v o l a t i l e s o l v e n t o r water-based c o a t i n g m a t e r i a l s .
4-6
The two dominant markets i n
WET SYSTEM
UV or
Electron Cured
Topcoat
Grain Print Inks
Base Coat
Very Thin Films (0.1 mil)
30 gm/m2
Filler Coating
90 gm/m2
Particle Board
0.3-3 cm
Thick
50 gm/m2
DRY SYSTEM
UV or
Electron Cured
Topcoat
~~
F i g u r e 4-2.
~
60 gm/m2
Decorated Paper
or Film
Laminating
Adhesive and
or Filler Coating
30 gm/m2
Particle Board
0.3-3 cm
Thick
90 gm/m*
-
R a d i a t i o n Curable Wood F i n i s h i n g Technology (52)
-
4-7
WET FINISHING
Particle
Board
Pigmented
Filler
Pigmented
Base Coat
Grain
Print
Clear
TOP
Coat
Panel of
Decorative
Wood
I
Lamination
With
Wood Veneer
DRY FINISHING
P
Tinting
Color
8
I
co
Printing
Printing
Impregnation
r
Varnishing
I
Rolling Up
I
Panel of
Decorative
Wood
Gluing on
Filled
Board
Figure 4-3.
I
Wood Finishing Operations
(50)
Clear
TOP
Coat
I
2
3
3
3
Varnishing of both faces: Speed 15 to 30 m h i n
P
I
u3
Total length of the line
- 60 to
65 m.
1 - Tinting of the wood (solvent
base)
2
3
- Thermal oven
- Sanding and vacuum cleaning
AI, A2
- Application with rollercoater of 15 g/mz
- 2 to 4 UV lamps of min 80
W/cm (both faces)
A3 - Application with roller-coater
UV
of 15 g/m* on one face only
Figure 4-4.
(50)
Varnishing and UV Curing/Finishing Line f o r F l a t Stock Wood Products
Table 4-2
RADIATION CURABLE COATINGS FOR WOOD FINISHING APPLICATIONS (30,36,50)
Coati nq Formul at i on
A1 kyds, polyesters, ureaformaldehyde, vi nyl s,
acryl i cs , urethanes; 3065% solids (solvent or
water based); clear polymer systems or containing
pigments
'
Curinq Conditions
Infrared oven 90 to
120 sec cure times
A w l i cat i on
Fi 1 1 er, base-coat
and top-coat
varnishes
Acryl ated polyester resin,
hexanediol di acryl ate,
vinyl pyrrol i done ,
photoinitiator
UV processor single
lamp, cure time of
10 seconds
C1 ear varni sh
Same as above but add
silica or titanium
dioxide pigments
UV processor sing1 e
lamp, cure time of
10-30 seconds
Filler or basecoat
65 wt percent unsaturated polyester, 35 wt
percent vinyl monomer:
2-ethylhexyl acrylate or
styrene acryl ic copolymers
containing pendant vinyl
unsaturation (unsaturation
levels, 0.5-1.75 mol of
double bonds per 1000 mol
wt) and 35-45 wt percent
of a vinyl monomer: 2ethyl hexyl acrylate or
styrene
Cured with 300 keV
electrons at 200
kGy/mi n (20 Mrad/mi n)
cured with a total
dosage of 150 kGy
(15 Mrad) electron
beam;
Coatings f o r
vinyl covered
flat board
stock
Acryl i c monomers : acryl i c
unsaturated epoxy and
acrylic unsaturated polyurethanes monomers: polyfunctional vinyl
intermediates
Electron-curtain
curing
4-1 0
4-1 1
Table 4-3
COMPARISON OF PERFORMANCE LIMITS AND TEST VALUES BETWEEN
HIGH AND LOW PRESSURE MELAMINE THERMALLY CURED LAMINATES
AND UNIFACE ELECTRON BEAM CURED PANELS (52)
Test
High
Pressure
Laminate
Unit
Low
Pressure
Laminate
Uniface
Test
Values
Hoffman Scratch Resistance
Grams
400
400
1200
Wear Resistance
LD3-3.01
Cycles t o
Fai l u r e
400
100
145
Impact Resistance
LD3-3.03
Inches
50
15
24
B o i l i n g Water Resistance
LD3-3.05
20 minutes
No E f f e c t
Slight Effect
No E f f e c t
High Temperature
Resistance LD3-3.06
20 minutes
Slight Effect
Slight Effect
No E f f e c t
4-1 2
t h i s i n d u s t r y a r e can c o n t a i n e r s and p r e f i n i s h e d c o i l s t o c k .
However, o n l y t h e can
manufacture and d e c o r a t i n g i n d u s t r y has s e r i o u s l y c o n s i d e r e d t h e use o f UV l i g h t
r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s f o r c u r i n g 100% r e a c t i v e i n k s , pigments, o r c l e a r
c o a t i n g systems.
A t y p i c a l can c o a t i n g l i n e , t h r e e - p i e c e , and two p i e c e c o n f i g u r e d
w i t h UV p r o c e s s i n g equipment i s shown i n F i g u r e 4-6.
The U.S.
c o i l c o a t i n g indus-
t r y has adopted o t h e r s o l v e n t r e c o v e r y or i n c i n e r a t i o n thermal oven equipment modi-
f i c a t i o n s so t h a t i t can c o n t i n u e t o use solvent-based ( l o w s o l i d s ) c o a t i n g systems
h a v i n g l o n g - t e r m proven performance c a p a b i l i t i e s .
T h i s i s n o t t h e case, however,
i n Japan where a t l e a s t one major s t e e l company i s u s i n g EB c u r a b l e c o a t i n g s on
m e t a l c o i l s t o c k because o f t h e i r s u p e r i o r f i n i s h and unique p r o p e r t i e s .
A more
d e t a i l e d d i s c u s s i o n o f t h i s process w i l l be r e p o r t e d i n t h e s e c t i o n o f t h i s r e p o r t
e n t i t l e d Global Trends i n R a d i a t i o n Processing o f Polymeric M a t e r i a l s . (53-57)
I n o t h e r areas, UV c u r a b l e c o a t i n g s a r e a p p l i e d t o aluminum o r g a l v a n i z e d s t e e l
t u b i n g f o r b o t h d e c o r a t i v e and p r o t e c t i v e purposes.
Galvanized s t e e l t u b i n g i s
manufactured f r o m a continuous s t r i p o f g a l v a n i z e d o r ungalvanized s t e e l which
i s g r a d u a l l y formed i n t o t h e d e s i r e d shape o r s i z e , and f i n i s h e d w i t h a UV-curable
c o a t i n g system ( F i g u r e 4-7).
A t y p i c a l UV lamp r a d i a t i o n p r o c e s s i n g c o n f i g u r a t i o n
f o r c u r i n g c o a t i n g s on a continuous t u b i n g o r p i p e l i n e i s shown i n F i g u r e 4-8.
The performance c h a r a c t e r i s t i c s f o r s e v e r a l g a l v a n i z e d s t e e l c o a t i n g f o r m u l a t i o n s
are shown i n Table 4-4.
(57)
P ac kag ing C o a t i ngs
P r o t e c t i v e h i g h g l o s s o v e r p r i n t c o a t i n g s have found g r e a t u t i l i t y i n t h e c o n v e r t i n g
and packaging i n d u s t r i e s .
B e f o r e t h e development o f r a d i a t i o n c u r a b l e c o a t i n g
t e c h n o l o g i e s t h i s i n d u s t r y had t h e f o l l o w i n g f i n i s h i n g choices:
0
0
0
0
(58)
solvent-base p r e s s v a r n i s h e s .
water-base c o a t i n g s .
l i q u i d laminations.
f i l m laminations.
I n s h e e t - f e d l i t h o g r a p h i c p r i n t i n g o p e r a t i o n s , solvent-base press v a r n i s h c o a t i n g s
l e a d on a volume b a s i s .
T h i s c l e a r v a r n i s h can be wet o r dry-processed on a press
and i m p a r t s a g l o s s y s u r f a c e b u t o n l y f a i r r u b o r a b r a s i o n r e s i s t a n c e .
Water-base
c o a t i n g s a r e g e n e r a l l y wet-processed on a s i x - c o l o r press and r e p l a c e t h e s o l v e n t - base press v a r n i s h system; t h e y p r o v i d e f a i r g l o s s and adequate t o f a i r a b r a s i o n
resistance.
L i q u i d l a m i n a t i o n c o a t i n g s a r e c a t a l y z e d , a p p l i e d o f f - p r e s s on a r o l l -
c o a t e r , and d r i e d o r c u r e d i n a 3 0 - f o o t oven.
Postcards and paperback book covers
undergo t h i s process; t h e c o a t i n g s p r o v i d e e x c e l l e n t g l o s s and h i g h f i n i s h q u a l i t y ,
4-1 3
Sheets of Tinplate,
Aluminum or
Tin-Free Steel
Overprint
Varnish
Three Piece Can Forming
Operations
(Body Formation and
End Capping)
Preformed 2 Piece
Aluminum Can
Printing
Roller
Overprint
Varnish Roller
Decorated
Product
Figure 4-6.
Radiation Curable Can Line Operation
4-1 4
(53,55)
Surface Treatment and/or UV Curable Coating
Application and Processing
Untreated
Steel
Surface Treatment and/or UV Curable Coating
Application and Processing
Galvanized
Steel
Fiat Coil
Strips
/
Cleaning
Figure 4-7.
Galvanized Steel Tubing Line
4-1 5
W
(57)
One of Four UV Lamps
One of Three UV Lamps
Galvanized
Galvanized Steel or Aluminum Tube
(Small Diameter)
Aluminum
Tube
(Large Diameter)
Figure 4-8. Cross Section o f Tube Line Surrounded by Three o r Four UV
Lamps (57)
4-16
Table 4-4
PROPERTIES OF TYPICAL UV CURABLE COATINGS
FOR GALVANIZED STEEL TUBING (57)
X
Formu1a t i on
V i s c o s i t y (cps @25O C)
Shrinkage
Penci 1 Hardness
Crosshatch and tape adhesion
(% removal)
MEK double rubs
90° bend and tape
(% removal a t bend)
.
Tensile, p s i
E l ongat ion, %
Modulus, p s i
Z
Y
490
8.2
3H
410
7.3
3H
260
7.9
3H
0
100
10
40
15
100
10%
4,800
14
160,000
25%
85%
4,500
9
130,000
3,900
3
140,000
Y
Z
Fog Corrosion Data
(Degree o f B1 i s t e r i n g )
100% R e l a t i v e Humidity (ASTM 2247) a t 38 C.
Formul a t ion
X
250 Hours
500 Hours
#10
#10
5% S a l t Spray (ASTM B-117) a t 35 C; pH 6.5 t o 7.2.
Formul a t ion
X
200 Hours
500 Hours
B l i s t e r size:
5% #8
20% #8
85% #8
95% #8
80% #a
90% #8
Y
Z
90% #4
Red r u s t
90% #4
Red r u s t
#lO=No b l i s t e r s ; #8,6,4 represent b l i s t e r s i n i n c r e a s i n g
s i z e , #4 being t h e l a r g e s t (see ASTM D-714).
Note:
X, Y, and Z represent d i f f e r e n t c o a t i n g f o r m u l a t i o n design parameters.
4-1 7
b u t t h e y are s o l v e n t based and r e q u i r e l a r g e amounts o f thermal energy and s e p a r a t e
p r o c e s s i n g equipment.
D i r e c t l a m i n a t i o n o f a p r o t e c t i v e p l a s t i c f i l m , such as a
p o l y e s t e r , i s another method o f a c q u i r i n g h i g h g l o s s and a p r o t e c t i v e c o v e r i n g , b u t
t h i s process i s expensive and r e l a t i v e l y slow compared t o t h e c o n v e n t i o n a l systems.
R a d i a t i o n processing, p r e d o m i n a n t l y UV, p r o v i d e s a l i q u i d c o a t i n g system o r l i q u i d
l a m i n a t i n g system c o m p a t i b l e w i t h t h e p r i n t e r ’ s e x i s t i n g equipment and c u r r e n t
p r o d u c t i o n schedule.
A
r a d i a t i o n c u r a b l e c o a t i n g process a l l o w s f o r b e t t e r q u a l i t y
t h a n t h e press v a r n i s h o r water-base c o a t i n g s , and e q u i v a l e n t p r o p e r t i e s t o a f i l m
l a m i n a t i o n process.
U l t r a v i o l e t c u r i n g i s now w e l l e s t a b l i s h e d ; hundreds o f l i t h -
o g r a p h i c and f l e x o g r a p h i c presses a r e equipped w i t h UV lamp systems.
beam equipment i s a l s o used on a
operations
. (59,601
Electron
im i ed b a s i s i n v e r y h i g h volume p r i n t i n g
F l o o r Coatings
R a d i a t i o n c u r a b l e c o a t i n g s have made a major impact on manufacture o f permanent
h i g h g l o s s , no-wax v i n y l f l o o r i n g t i l e s and sheet p r o d u c t s .
The c o n v e n t i o n a l
method o f s u r f a c e f i n i s h i n g these p r o d u c t s i n v o l v e s a p p l i c a t i o n o f a s o l v e n t (hydrocarbon o r water based) o r 100% s o l i d s two component urethane c o a t i n g t o t h e
s u b s t r a t e (3-5 m i l t h i c k u n i f o r m c o a t i n g s ) f o l l o w e d b y low temperature thermal
c u r i n g t e c h n i q u e s o r b y m o i s t u r e c u r i n g i s o c y a n a t e r e a c t i o n s under room temperature
s t o r a g e and d r y i n g c o n d i t i o n s . (61)
Radiation curable coatings
(UV i s t h e energy system o f c h o i c e f o r t h i s i n d u s t r y )
c o n t a i n 100% s o l i d s and have b e t t e r o v e r a l l p h y s i c a l and chemical p r o p e r t i e s than
t h e i r c o n v e n t i o n a l urethane polymer c o a t i n g c o u n t e r p a r t s (Table 4-5).
These UV--
c u r a b l e c o a t i n g s a r e tough and can be e a s i l y a p p l i e d t o sheet o r c u t t i l e p r o d u c t
l i n e s as shown i n F i g u r e 4-9.
(62,631
Wire Coatings
R a d i a t i o n ( U V ) c u r a b l e c o a t i n g s f o r w i r e a r e m a t e r i a l s t h a t can be processed i n t o
h i g h l y cross-linked,
tough, f l e x i b l e f i l m s .
They can be coated and cured on e i t h e r
b a r e o r i n s u l a t e d w i r e a t h i g h l i n e speeds u s i n g simple, low-cost equipment ( F i g u r e
4-10).
F i l m c o a t i n g s o f 10 m i l s a r e e a s i l y a t t a i n a b l e i n one pass.
A
typical
a p p l i c a t i o n i s magnet w i r e enamels, which a r e coated c o n v e n t i o n a l l y w i t h s o l u t i o n s
c o n t a i n i n g t o x i c o r h i g h b o i l i n g p o i n t s o l v e n t s , r e s u l t i n g i n a i r p o l l u t i o n problems and consumption o f l a r g e amounts o f gas t o o p e r a t e t h e d r y i n g l c u r i n g ovens
and a n t i p o l l u t i o n a f t e r b u r n e r s .
U l t r a v i o l e t c u r a b l e magnet w i r e enamels e l i m i n a t e
4-1 8
Table 4-5
COMPARISON OF PROPERTIES FOR CONVENTIONAL AND RADIATION
CURABLE COATINGS FOR VINYL FLOORING PRODUCTS (61)
Abrasion Resistance
Solvent Resistance
300 micrograms l o s t
per c y c l e using a
Tabor Abrader CS-10
wheel w i t h a 500
gram l o a d
No r e s i s t a n c e t o
methyl e t h y l
ketone (MEK)
Conventional
Urethane Coating
75- 100 micrograms
l o s t per c y c l e
F a i r resistance t o
MEK
UV c u r a b l e u r e thane a c r y l i c s
20 micrograms
l o s t per cycle
Excel 1e n t MEK
r e s i stance
Urethane Coatinq
None
4-1 9
S t a i n Resistance,
L i pstick/Mustard
None
Mustard o n l y
Excel 1ent
Calendar
Rolls
Emboss
and/or
Print
Direct
Roll
Coater
UV Cure
o n
c
QQQQ
12OOF
bSheet
J
110-220°F
0.2-15 sec
160-180°F
80-200 ft/min
Sheet or Post-Cut Tile
Forming
Emboss
and/or
Print
Cut
Direct
UV Cure
Roll
Coater
-
J
O
Precut Tile
Figure 4-9.
Radiation Curable Floor Sheet and Floor T i l e Product Line
4-20
(63)
Ball Die
II
Mercury UV
Lamp
UV Curable
Wire Coating
I
1I
A
-
Pulsed
Xenon
Lamp
L
I
I
I
Figure 4-10.
* ----E
1
Snubber
I
Typical Wire Coating Lines
4-21
(64)
these problems w h i l e m a i n t a i n i n g acceptable performance p r o p e r t i e s ( T a b l e
4-61,
(64)
Other nonmagnet w i r e a p p l i c a t i o n s f o r r a d i a t i o n c u r a b l e polymers a r e as f o l l o w s :
@
Primary i n s u l a t i o n where a c r o s s - l i n k e d polymer i s r e q u i r e d f o r
thermal , and s o l v e n t r e s i s t a n c e .
@
As an o v e r c o a t f o r g l a s s and t e x t i l e b r a i d w i r e t o p r e v e n t
b r a i d u n r a v e l i n g and t o i m p a r t s o l v e n t and f l a m e r e s i s t a n c e .
@
As a t h i n overcoat on p o l y v i n y l c h l o r i d e i n s u l a t e d w i r e t o
impart:
-
-
improved s l i p ,
improved heat r e s i s t a n c e ,
improved appearance
As a t h i n overcoat on p o l y e t h y l e n e i n s u l a t e d w i r e t o i m p a r t :
-
improved heat r e s i s t a n c e ,
greater flame retardance
Primary i n s u l a t i o n i n t h e 5-10 m i l t h i c k range f o r small-gage
wire requiring t h i n wall insulation.
@
T r a n s p o r t a t i o n (Automotive 1 Coatings
R a d i a t i o n c u r a b l e c o a t i n g s ( u s i n g e l e c t r o n beam t e c h n i q u e s ) were f i r s t i n t r o d u c e d
t o t h e automotive i n d u s t r y i n t h e e a r l y 7 0 ' s b y t h e F o r d Motor Company t o f i n i s h
c e r t a i n t y p e s o f p l a s t i c i n s t r u m e n t panels.
This technology was d i s c o n t i n u e d i n
1979 i n f a v o r o f o t h e r competing types o f m a n u f a c t u r i n g / f i n i s h i n g o p e r a t i o n s .
R e c e n t l y , however, r a d i a t i o n c u r a b l e c o a t i n g s ( U V , EB, and I R ) have f o u n d an opport u n i t y i n f i n i s h i n g automotive hubcaps and wheel r i m s i n t h e
Europe.
I n one U.S.
U.S., Japan, and
o p e r a t i o n ( J a y P l a s t i c s , M a n s f i e l d , Ohio) a s p e c i a l i z e d metal
s p u t t e r - c o a t i n g l i n e r u n s high-speed I R and UV c u r a b l e base c o a t i n g and t o p c o a t i n g
materials.
T h i s f i n i s h i n g l i n e ( F i g u r e 4-11) r e p r e s e n t e d a v e r y l a r g e c a p i t a l
e x p e n d i t u r e f o r t h e company, which based i t s s e l e c t i o n on t h e s h o r t p r o d u c t c y c l e
t i m e (70% s h o r t e r :
45 minutes versus 3 t o 4 h o u r s ) , h i g h r e f l e c t i v i t y p r o d u c t
s u r f a c e s , and low c o s t p r o d u c t a c h i e v a b l e w i t h t h e new system.
PRINTING
The p r i n t i n g i n k i n d u s t r y , l i k e t h e c o a t i n g i n d u s t r y , has many s e c t i o n s , each one
s u p p l y i n g a s p e c i a l market area.
A rough e s t i m a t i o n o f t h e p r o d u c t l i n e d i v e r s i t y
o f t h i s i n d u s t r y i s shown i n Table 4-7 which r e l a t e s v a r i o u s p r i n t e d p r o d u c t s w i t h
t h e i r e q u i v a l e n t d o t d e n s i t y ( d o t s p e r i n c h ) requirements and p r i n t i n g p r e s s cap-
4-22
Table 4-6
AVERAGE PROPERTIES OR RADIATION CURABLE COATINGS
IN MAGNET WIRE APPLICATIONS (64)
Average Property
Values
ProPerties
Modul us (psi )
Tensile (psi)
Percent elongation
Dielectric constant 60 Hz
Dielectric constant 1 MHz
Dissipation factor 60 Hz
Dissipation factor 1 MHz
Volume resistivity (ohm-cm)
Surface resi sti vi ty
Dielectric strength (volt/mil)
Arc resistance (sec)
Cut through (C)
Snap test
Scrape (9)
6,000-250,000
1,000-7,400
6-340
3.81-8.03
2.49-5.75
0.006-0.1
0.01-0.07
6.6x1Ol2-5. 1x1Ol5
3~10~-3.6~10~~
865-1,050
3.2-111
290-335
Pass
600-1,200
Note: UV-curable coatings based on W. R. Grace thiol-polyene
chemistry, 0.5 t o 10 mil films cured at line speeds up to 150 ppm.
4-23
Start
Topcoat Line (60 ft)
F i g u r e 4-11.
F i n i s h i n g L i n e f o r High-speed
4-24
I R and UV Curable Coatings (65)
T a b l e 4-7
P R I N T I N G INDUSTRY PRODUCT D I V E R S I T Y (661
W
+
E
22
E
8
3
0
8
3
8
6
0
Textile Imaging
Wallpaper
Wood Grain Paneling
Address Labels, No OCR
Computer Letters, No OCR
Computer Letters, OCR
Bus. Forms Imprint
Bus. Forms, Complete
Computer Reports
Tags
Mass Paperback
“Best Seller” Hardbound
Technical, Short Run
Deluxe Hardbound
Art Quality Book
Scroll Book
Proof Book
Newspapers and Similar
Gen. Magazines, etc.
Quality, 4 Color
sn
5 (3
Z
gz
Low Quality
Medium Quality
High Quality
8E
3Y
2-Color
4-Color, Quality
2
n
Computer Line Printer
Flexographic Press
Offset Press
Letterpress
Gravure
4
0
4-25
200
400
600
800
1000
a b i l i t i e s r e q u i r e d t o produce them. (66)
major p r i n t i n g processes:
screen p r i n t .
T h i s i n d u s t r y can be d i v i d e d i n t o f i v e
l e t t e r press, l i t h o g r a p h y , f l e x o g r a p h y , gravure, and
Each process and t h e r e q u i r e d equipment can be d e s c r i b e d as
f o l l o w s . (67,681
L e t t e r p r e s s Process
The l e t t e r p r e s s process ( F i g u r e 4-12) uses r a i s e d c h a r a c t e r s on f l a t o r c u r v e d
s u r f a c e s which a r e i n k e d and then pressed i n c o n t a c t w i t h t h e paper, c o r r u g a t e d
c a r t o n s , o r p l a s t i c f i l m s u b s t r a t e s i n o r d e r t o e f f e c t image t r a n s f e r .
presses can r u n a t 1500 t o 20,000
These
impressions per hour, use i n k s h a v i n g v i s c o s i t i e s
between 2 and 400 p o i s e a t 25 C and can d e l i v e r f i l m t h i c k n e s s values i n t h e 3-5 p m
r e g i o n . (69-71)
Lithography
I n a l i t h o g r a p h i c press o p e r a t i o n , b o t h t h e p r i n t i n g s u r f a c e and t h e i m p r e s s i o n
a r e c a r r i e d on c y l i n d e r s .
The p r i n t i n g s u r f a c e i s u s u a l l y a photo-hardened n a t u r a l
polymer, rubber, or p l a s t i c .
The n o n p r i n t i n g impression c y l i n d e r i s a w a t e r -
w e t t a b l e high-energy s u r f a c e c o n s i s t i n g o f a g r a i n e d t h i n metal p l a t e (aluminum,
zinc, s t a i n l e s s s t e e l ) surface.
Another v a r i a t i o n o f t h i s t e c h n i q u e i s t o use a
b i m e t a l p l a t e c o m p r i s i n g a p r i n t i n g area o f copper and a n o n p r i n t i n g area o f chromium.
The p r i n t i n g p l a t e i s water dampened and i n k e d s u c c e s s i v e l y b y two s e t s o f
r o l l e r s f o l l o w e d b y d i r e c t c o n t a c t w i t h a paper s u b s t r a t e .
It i s also possible t o
o f f s e t t h i s process such t h a t t h e i n k f r o m t h e image i s t r a n s f e r r e d f i r s t t o a
rubber b l a n k e t e d c y l i n d e r and t h e n f r o m t h e r u b b e r s u r f a c e t o t h e paper, metal o r
p l a s t i c s u b s t r a t e c a r r i e d on an i m p r e s s i o n c y i n d e r ( F i g u r e 4-13).
o f l i t h o g r a p h i c i n k s range f r o m 100 t o 800
PO
The v i s c o s i t es
se a t 25 C and a r e u s u a l l y a p p l i e d a t
f i l m t h i c k n e s s values i n t h e 2 t o 3 pm range. (72-74)
F lexography
Flexography i s a method o f p r i n t i n g s i m i l a r t o l e t t e r p r e s s o r " r e l i e f " p r i n t i n g ,
i n t h a t t h e image p o r t i o n s a r e r a i s e d above t h e nonimage areas f o r p r i n t i n g ( F i g u r e
4-14).
F l e x o g r a p h i c p r i n t i n g employs rubber o r e l a s t o m e r i c p r i n t i n g p l a t e s and
c y l i n d e r s , and uses v e r y r a p i d d r y i n g f l u i d i n k s having v i s c o s i t i e s i n t h e range o f
0.5 t o 5 p o i s e a t 25 C.
The f l e x o g r a p h i c p r i n t i n g process i s unique among t h e
processes o f p r i n t i n g i n t h a t i t was developed p r i m a r i l y f o r t h e p r i n t i n g o f a v a s t
range o f packaging m a t e r i a l s .
T h i s p r i n t i n g system has developed as a web f e d
method o f p r o d u c i n g continuous r o l l f o r m f e e d i n g f o r wrappings, bag making, e t c .
4-26
c
Q
h
4- 27
Ink-Distributing
Water
Dampening
System
Blanket
Cylinder
Figure 4-1 3 .
Lithography Process
4-28
(67)
Substrate
/
Rubber Printing Plate
1
Ink Fountain
F i gure 4-1 4.
F1 exography Process (67)
4-29
Impression
Cylinder
The rubber p r i n t i n g p l a t e s used i n t h e process o f f e r advantages over o t h e r p r i n t i n g
processes by t h e i r a b i l i t y t o p r i n t on an e x t r e m e l y wide range of m a t e r i a l s .
Also
advances i n techniques f o r p r i n t i n g m u l t i - c o l o r h a l f t o n e work have opened up new
commercial areas o f t h e p r i n t market.
I n i t s most common form, t h e f l e x o g r a p h i c p r i n t i n g method comprises a f o u r p a r t
system, as f o l l o w s :
0
A rubber covered f o u n t a i n r o l l which t u r n s i n a b a t h o f i n k ,
0
A smooth o r engraved i n k t r a n s f e r r o l l which r u n s f r o m f o u n t a i n
r o l l t o printing plate,
0
A plate cylinder,
0
An impression c y l i n d e r - t o m a i n t a i n p r e s s u r e between paper,
e t c . and t h e p l a t e c y l i n d e r .
S l i g h t v a r i a t i o n s f r o m t h i s common f l e x o g r a p h i c p r i n t i n g system a r e p o s s i b l e depending on t y p e o f work t o be p r i n t e d and t h e equipment i n use; f o r example, a
d o c t o r b l a d e may be i n t r o d u c e d i n s t e a d o f an i n k t r a n s f e r r o l l e r .
Other v a r i a t i o n s
a l l o w t h e f o u n t a i n r o l l e r t o i n k t h e impression p l a t e s d i r e c t l y w i t h o u t u s i n g an
ink transfer roller.
I n i t s b a s i c f o r m t h e p r i n t i n g press i s made up o f a combina-
t i o n o f unwinding, p r i n t i n g , d r y i n g , and r e w i n d i n g u n i t s . (75,761
Gravure
I n gravure p r i n t i n g a p r i n t i n g s u r f a c e i s e i t h e r c h e m i c a l l y o r m e c h a n i c a l l y engraved w i t h a range o f " c e l l s " which v a r y i n depth, c r o s s - s e c t i o n a l area, and d i s t r i b u t i o n , depending on t h e p r i n t design r e q u i r e d and t h e engraving method
used.
The p r i n t i n g c y l i n d e r may c o n s i s t o f a s o l i d i r o n base (mounted on a s h a f t ) on
which a l a y e r o f copper i s d e p o s i t e d .
T h i s copper l a y e r i s engraved and may sub-
s e q u e n t l y be chromium p l a t e d t o g i v e r e s i s t a n c e t o wear d u r i n g l o n g press r u n s .
A l t e r n a t i v e l y , t h e copper may be i n t h e f o r m o f a c y l i n d r i c a l s l e e v e which f i t s
o n t o a separate base.
The p r i n t i n g c y l i n d e r i s g e n e r a l l y mounted i n t h e g r a v u r e machine so t h a t i t i s
p a r t i a l l y covered by t h e i n k which i s p l a c e d i n an i n k d u c t , and, when i t s r o t a t e d ,
a f l e x i b l e d o c t o r blade removes s u r f a c e i n k , l e a v i n g i n k o n l y i n t h e c e l l s .
Thus
when a s u b s t r a t e i s p l a c e d i n c o n t a c t w i t h t h e c y l i n d e r under t h e impression o f a
4-30
rubber backing r o l l e r , t h e i n k i n t h e c e l l s t r a n s f e r s t o t h e s u b s t r a t e .
The grav-
u r e i n k u s u a l l y d r i e s e n t i r e l y by e v a p o r a t i o n , t h e l i q u i d ( o r s o l v e n t ) p o r t i o n
o f t h e i n k b e i n g removed d u r i n g t h e d r y i n g process.
T h i s enables b o t h absorbent
and nonabsorbent s u r f a c e s t o be p r i n t e d i n b o t h r e e l and sheet f o r m and, p r o v i d e d
t h a t a l l l i q u i d components o f t h e i n k are removed, t h e p r i n t s may be r e r e e l e d i m mediately following printing.
The v i s c o s i t y o f t h e i n k s used i n t h i s process
v a r i e s f r o m 0.3 t o 2 p o i s e a t 25 C and t h e s u b s t r a t e s p r i n t e d may be paper, board,
f o i l , o r f i l m m a t e r i a l s w i t h i n k f i l m t h i c k n e s s values between 8 t o 12 pm F i g u r e
4-15).
(77,78)
Screen P r i n t i n g
Screen p r i n t i n g i s e s s e n t i a l l y a s t e n c i l i n g o p e r a t i o n i n which heavy i n k f i l m s ( i n k
v i s c o s i t y values range f r o m 1,000 t o 4,000 cps w i t h f i l m t h i c k n e s s values r a n g i n g
f r o m 30 t o 70 p m ) a r e a p p l i e d by brush o r b l a d e o n t o a preimaged p r i n t i n g screen
s u b s t r a t e ( F i g u r e 4-16).
The p r i n t i n g screen can be s i l k , n y l o n , o r m e t a l ; t h e
image i s prepared on t h e screen b y p h o t o l i t h o g r a p h y techniques.
Screen p r i n t i n g i s
b e i n g used on t e x t i l e s , r i g i d and f l e x i b l e p l a s t i c s u b s t r a t e s (such as p l a s t i c
cups, v i n y l w a l l p a p e r f i l m s ) , and p r i n t e d c i r c u i t boards f o r t h e e l e c t r o n i c s
industry.
(68)
Radiation Curing Applications i n P r i n t i n g
P r i n t i n g i n k manufacturers and p a r t i c l e board f i n i s h e r s were t h e f i r s t t o commerc i a l i z e UV t e c h n o l o g y as an a l t e r a t i v e t o c o n v e n t i o n a l t h e r m a l l y c u r e d ( n a t u r a l
gas) solvent-based i n k and c o a t i n g systems.
U l t r a v i o l e t r a d i a t i o n processing,
r a t h e r than EB, was p r e f e r r e d because o f t h e compact s i z e , low c o s t , f a s t product i o n r a t e s , p r o d u c t design f l e x i b i l i t y , l a c k o f p o l l u t i o n , and ease o f maintenance.
A i r p o l l u t i o n l e g i s l a t i o n i n C a l i f o r n i a and p o s s i b l e f o s s i l f u e l energy c o s t
increases are s t i l l issues o f today t h a t f a v o r solvent-free,
c u r a b l e i n k p r o c e s s i n g systems.
low-energy r a d i a t i o n
Other advantages o f UV and EB processes are t h e
a b i l i t y t o r e p l a c e thermal oven c u r i n g u n i t s w i t h a s u b s t a n t i a l r e d u c t i o n i n c o s t
and even g r e a t e r r e d u c t i o n i n f l o o r space requirements.
I n multicolor printing
o p e r a t i o n s t h e s i z e and c u r e speed a s s o c i a t e d w i t h UV o r EB processors a l l o w f o r
i n s t a n t a n e o u s c u r i n g between s t a t i o n s and e l i m i n a t e s problems o f b l o c k i n g o r smearing.
Since r a d i a t i o n c u r a b l e i n k s remain l i q u i d (100% r e a c t i v e l i q u i d systems)
u n t i l a c t i v a t e d b y e l e c t r o m a g n e t i c r a d i a t i o n , t h e y do n o t d r y i n i n k r e s e r v o i r s as
i s t h e case w i t h c o n v e n t i o n a l s o l v e n t a p p l i e d i n k systems.
Some general charac-
t e r i s t i c s o f UV o r EB c u r a b l e i n k f o r m u l a t i o n s a r e shown i n Table 4-8;
a two c o l o r
o f f s e t p r i n t i n g p r e s s o p e r a t i o n f i t t e d w i t h e i t h e r UV o r EB r a d i a t i o n p r o c e s s i n g
4-31
\
Impression
Cylinder
Printing
Plate
Cylinder
Doctor
Blade
\
Ink
Reservoir
Fi gure 4-1 5.
Gravure Printing Process
4-32
(67)
Ink Applicator
Blade
Imaged
Screen
Figure 4-16.
Screen P r i n t i n g Process
4-33
(67,681
Table 4 - 8
STANDARD (CONVENTIONAL THERMAL CURE)
AND UV/EB INK FORMULATIONS (68)
Lithoqraphic or Standard Ink
Li tho1 Rubine Pigment
Drying Oil A1 kyd
Phenol i c Res i n
Driers, Other Additives
470 Oil
UV/EB Ink
Pigment
UV Vehicle
Photoinitiatora
Multi-functional
Monomer
Add i ti ve s
20%
1 5%
3 0%
4%
31%
29%
54%
5%
10%
2%
100%
100%
Standard Gravure Ink
Lithol Rubine Pigment
Ni trocell ul ose
Maleic Rosin Ester
n-Propyl Acetate
To1 uene
UV/EB Ink
Pigment
01i gomer
15.0
4.0
60.0
Monomer
Photoinitiatora
Additives
27.4
19.0
100.0%
UV/EB Curable Flexo Ink
Pigment
01i gomer
Monomer
Photoinitiatora
Additives
11.0%
12.0
2.0
35.0
30.0
10.0
44.0%
15.0
32.0
5.0
4.0
100.0%
100.0%
UV/EB Screen Ink
Standard Screen Ink
Lithol Rubine Pigment
Thermoplastic Vinyl
Resin
Thermoplastic Acryl ic
Resin
Addi ti ves
Cyclohexanone
IsoDhorone
Butyl Cell os01 ve
5.0
6.0
100.0%
Standard FlexoqraDhic Ink
Lithol Rubine Pigment
Polyamide Resin
Add i ti ves
Ethanol
N- ProPanol
N-Probyl Acetate
47.6%
10.0%
7.0
30.0%
Pigment
60.0%
10.0
01i gomer
15.0
15.0
5.0
Monomer
Photoinit atora
Additives
15.0
5.0
5.0
20.0
10.0
10.0
100.0%
100.0%
.
.
Evaluation properties:
Cure, scr tch resistance, rub re i stance,
flexibility, adhesion, gloss, pr n t strength ,
and odor after curing.
m o t o i n i t i a t o r is not required in the EB ink formulations.
4-34
equipment i s shown i n F i g u r e 4-17.
(79,801
The m a j o r i t y o f t h e p r i n t i n g i n d u s t r y
u t i l i z e s UV l i g h t p r o c e s s i n g equipment ( o v e r 300 i n s t a l l a t i o n s ) ,
b u t EB p r o c e s s i n g
o f i n k m a t e r i a l s i s b e i n g used i n s p e c i a l v e r y h i g h q u a l i t y g r a p h i c a r t s a p p l i c a t i o n areas where speed and c e r t a i n p r o d u c t i o n techniques can o n l y be achieved w i t h
EB technology.
The major areas i n t h e p r i n t i n g market p e n e t r a t e d by r a d i a t i o n p r o c e s s i n g ( a l m o s t
e x c l u s i v e l y U V ) have been i n t h e o f f s e t ( l i t h o g r a p h i c ) , s i l k screen, and, t o some
degree, f l e x o g r a p h i c areas; v e r y l i m i t e d i n r o a d s have been made i n t o g r a v u r e market
segments.
P a r t o f t h e reason f o r l a c k o f market p e n e t r a t i o n i n t h e g r a v u r e area i s
due t o competing t e c h n o l o g i e s such as water-based i n k s and s o l v e n t r e c l a i m o r i n c i n e r a t i o n equipment m o d i f i c a t i o n s now r e a d i l y a v a i l a b l e f o r i n s t a l l a t i o n on e x i s t i n g p r i n t i n g equipment.
The two most i m p o r t a n t areas f o r UV p r i n t i n g i n k process-
i n g o p e r a t i o n s a r e i n t h e p u b l i s h i n g / p r i n t i n g t r a d e (books , p e r i o d i c a l s , composer
p r i n t i n g ) and packaging t r a d e (metal and p l a s t i c c o n t a i n e r b o t t l e l a b e l s , f o l d i n g
paperboard c a r t o n s f o r f o o d and beverages, wraps, d e t e r g e n t s , tobacco, cosmetics,
and medicines 1.
A unique method o f p r i n t i n g rounded p l a s t i c c o n t a i n e r s has been demonstrated u t i -
l i z i n g UV energy d i r e c t e d a t t h e p r o d u c t on a s p i n n i n g mandrel apparatus r a t h e r
t h a n on a l i n e a r p r o d u c t i o n l i n e c o n f i g u r a t i o n ( F i g u r e 4-18).
Concepts o f u l t r a -
v i o l e t d r y i n g o f i n k s on p l a s t i c c o n t a i n e r s (cups, t u b s , j a r s , tubes, and b o t t l e s )
has d r a m a t i c a l l y reduced t h e u n i t c o s t o f p r o d u c t s w i t h an average i n c r e a s e o f 33%
p r o d u c t o u t p u t p e r p r i n t e r due t o e l i m i n a t i o n o f c o n t a i n e r h a n d l i n g problems.
(81)
ADHESIVES
The adhesives i n d u s t r y can be c a t e g o r i z e d as d i f f u s e and u n s t r u c t u r e d ; p r o b a b l y
more t h a n 1,000 manufacturers s u p p l y a v e r y d i v e r s e end-use market area (Table
4-9).
Approximately e i g h t major producers account f o r about 30% o f t h e o u t p u t f o r
t h i s industry.
The p r i n c i p a l adhesives b y t y p e a r e s y n t h e t i c r e s i n s , n a t u r a l
r e s i n s , s e a l a n t s , and c a u l k s .
These broad market area c l a s s i f i c a t i o n s ( F i g u r e
4-19) cover a wide range o f p r o d u c t s t h a t use a p p r o x i m a t e l y 38 d i f f e r e n t t y p e s of
polymer m a t e r i a l s ( T a b l e 4-10) b r o a d l y c l a s s i f i e d as p r e s s u r e s e n s i t i v e o r nonpressure sensitive.
The same general p o l y m e r - s o l v e n t c l a s s i f i c a t i o n scheme ( h i g h
s o l i d s , powder, 100% s o l i d s , e t c . )
as t h e one f o r t h e c o a t i n g s i n d u s t r y i s used i n
t h e adhesives i n d u s t r y ( T a b l e 4-11).
(82)
R a d i a t i o n p r o c e s s i n g o f adhesive mate-
r i a l s i n v o l v e s a major use o f s y n t h e t i c polymers and i s commonly a s s o c i a t e d w i t h a
s t r u c t u r a l o r s p e c i a l t y market area.
A breakdown o f t h i s s t r u c t u r a l and s p e c i a l t y
adhesive market area f o r 1983 i s shown i n T a b l e 4-12.
4-35
(83)
EB Generator
Triode
System
Two Colour
Off Set
Roll on
PaDer
uv cure
Processing
Unit
P
I
w
l
n
Ink
Figure 4-17.
I
I
Offset Press Process w i t h UV Cure and EB Cure Processing Units
(a)
On-Mandrel Dryer Configuration for Tapered Wall Containers
(64 sq ft Total Processor Area Required)
-
Light
Shielding
Take Off Tube
to Counter
Print
"OV
Pretreat for Adhesion Promotion
Conventional Cup Dryer Lamp Linear Configuration
(184 sq ft Total Processor Area Required)
Figure 4-18.
Dryer Configurations
4-37
(81)
Table 4-9
ADHESIVES MARKET SUPPLIERS AND PRODUCTS (82)
Packaging
f
0
Corrugated board manufacture
Carton side-seam and closures
Composite bonding of disposable
products
Bags
Labels
cups
Cigarette and filter manufacture
Envelope manufacture
Remoi s tenab 1e products
Flexible laminates
Specia1ty packages
Composite containers and tubes
Tapes
03
Construction
Acoustic ceiling panels, floor tile,
and continuous flooring installation
Ceramic tile installation
Counter top lamination
Manufacture of prefabricated beams
and trusses
Carpet 1 ayment adhesives
Flooring underlayment adhesives
Installation o f prefinished panels
Joint cements
Curtain wall manufacture
Wall covering instal1 ation
Dry wall lamination adhesives
Other Nonrigid Bonding
Fabric combining
Apparel 1 aminates
Shoe assembly
Sports equipment
Book binding
Rug backing
Flocking cements
Air and liquid filter manufacture
Packaging tapes
Industrial tapes
Surgical tapes
Masking tapes
Consumer tapes
Consumer Adhesives
Do-it-yourself products
Model and hobby supplies
School and stationery products
Decorative films
I
I
Transportati on
Auto, truck, and bus interior trim
attachment
Auto, truck, and bus exterior trim
attachment
Vinyl roof bonding
Auto, truck, and bus assemblies
Weatherstrip and gasket bonding
Aircraft and aerospace structural
assemblies.
Other Rigid Bonding
Shake proof fastening
Furniture manufacture
Manufacture of millwork, doors,
kitchen cabinets, vanitories
Appliance assembly and trim
attachment
Houseware assembly and trim
attachment
TV, radio, and electronics assembly
Machinery manufacture and assembly
Supported and unsupported film
1 ami n ati on
Manufacture of sandwich panels
A
B
C
D
E
F
Figure 4-19.
=
=
=
=
=
=
Construction
Transportation
Rigid
Packaging
Non-Rigid
Consumer
Adhesive Market Area C l a s s i f i c a t i o n
4-39
15%
3%
5yo
46%
19%
5%
7%
Table 4-10
ADHESIVES INDUSTRY POLYMER-SOLVENT CLASS IF I CATION
(82)
Synthetics
Acrylics
Modified acrylics
Ami nopl asts
Anaerobi cs
Cyanoacrylates
Epoxies
Butyl rubber
Nitrile (NBR) rubber
Neoprene
Phenol i cs
Polyamides
Polyi sobutylenes
Polyesters (thermoplasti c)
Polyesters (thermosetting)
Polyethylene
Other po 1 yo 1 ef i ns
Block SBR polymers (example: Kraton D)
Other SBR resins (styrene butadiene rubber)
Other styrene polymers and copolymers
Silicones
Urethanes (thermoplastic)
Urethanes (thermosetting)
Acrylic-vinyl acetate copolymers
Ethylene-vinyl acetate copolymers (50+% ethylene)
Vinyl acetate-ethylene copolymers (50+% vinyl acetate)
Other vinyl acetate polymers and copolymers
Other vinyls (including polyvinyl alcohol)
Natural
Bitumens
Casein
Cellulosics
Hydrocarbon resins
Terpene resins
Rosin and rosin esters
Natural rubber
Reclal” rubber
Starches and dextrines
Others
4-40
Table 4-11
ADHESIVE TECHNOLOGIES
Non-Pressure Sensi t i v e s
(82)
Pressure S e n s i t i v e s
Solvent-borne systems
Waterborne systems
N o n - v o l a t i l e s o l i d o r l i q u i d systems
Hot m e l t s (100% s o l i d s )
Powders (100% s o l i d s )
Radia t io n c u r a b 1e systems
(100% s o l i d s )
Two-part systems
Solvent-borne systems
Waterborne systems
Hot m e l t s
R a d i a t i o n c u r a b l e systems
R e a c t i v e systems
Pressure s e n s i t i v e adhesives ( P S A ) a r e a p o t e n t i a l s p e c i a l t y market f o r r a d i a t i o n
c u r e d polymers; p r e s s u r e s e n s i t i v e ( P S ) tapes and l a b e l s c o u l d c o s t l e s s t o manuf a c t u r e b y r a d i a t i o n p r o c e s s i n g and c o u l d e x h i b i t improved performance p r o p e r t i e s
over c o n v e n t i o n a l t h e r m a l l y cured s o l v e n t based adhesive systems.
This technology
u t i l i z e s a l a r g e volume o f polymers a p p l i e d t o preformed h e a t - s e n s i t i v e t a p e subs t r a t e s and i s s u i t e d t o b o t h EB and UV p r o c e s s i n g o p e r a t i o n s . (84
L
85)
H e a t - a c t i v a t e d adhesives, h o t m e l t s ( d r y f i l m s t h a t become t a c k y upon a p p l i c a t i o n
o f h e a t and p r e s s u r e and upon c o o l ing f o r m h i g h - p e r f ormance bonds 1 a r e commerci a1 l y
a v a i l a b l e as t a c k - f r e e f i l m s supported on paper, f o i l , f a b r i c , board, o r f i l m subs t r a t e s ( F i g u r e 4-20).
(86)
R a d i a t i o n p r o c e s s i n g a l l o w s f o r t h e manufacture o f
t h e s e p r o d u c t s w i t h o u t t h e use o f s o l v e n t s f o r improved e f f i c i e n c y , s a f e t y , a i r
p o l l u t i o n c o n s t r a i n t s , and lower o p e r a t i n g c o s t s ( T a b l e 4-13).
L a m i n a t i n g adhes-
i v e s o r adhesives f o r f l e x i b l e packaging i s another area w e l l s u i t e d f o r r a d i a t i o n
processing operations.
A l a m i n a t o r c o a t e r w i t h a EB ( f l a t p l a n a r cathode) c u r i n g
head i s shown i n F i g u r e 4-21 and a t y p i c a l f i l m l a m i n a t i o n p r o d u c t performance
sheet i s shown i n T a b l e 4-14.
Some general a p p l i c a t i o n areas f o r h e a t - a c t i v a t e d
adhesive f i l m s and l a m i n a t e s t r u c t u r e s a r e g i v e n i n Table 4-15.
(86-88)
ELECTRONICS AND COMMUNICATIONS
R a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s has a t t a i n e d major importance i n v a r i ous segments o f t h e e l e c t r o n i c s and communication i n d u s t r i e s .
A typical printed
c i r c u i t board ( F i g u r e 4-22) i l l u s t r a t e s some o f t h e many d i f f e r e n t c l a s s e s o f p o l y m e r i c m a t e r i a l s used i n i t s manufacture.
Other m a t e r i a l s used i n t h e e l e c t r o n i c s
i n d u s t r y a r e s i l i c o n ( s u b s t r a t e f o r i n t e g r a t e d c i r c u i t s and c h i p s ) , p h o t o r e s i s t s
(used i n p r e p a r i n g c i r c u i t s ) , dopants f o r c i r c u i t a c t i v a t i o n , t h i n f i l m
(conformal 1, and e n c a p s u l a t i n g m a t e r i a l s .
4-41
Table 4-12
STRUCTURAL AND SPECIALTY ADHESIVES MARKETS
($ million)
(E-)
1983
Au tomot i ve
42
Aerospace
100
Construction
460
Biomedical /dental
12
Electronic/pott i ng
125
Nonrigid
200
98
Rigid bonding
(anaerobic,
cyanoacrylate, etc. )
1,037
Total
Table 4-13
ADVANTAGES OF HIGH-ENERGY ELECTRON ADHESIVES
(86)
Low volatility, 100% convertible
Rapid cure rate
Air pollution eliminated or reduced substantially
Catalysts and initiators are eliminated
No thermal postcure required
Improved process control
Outstanding adhesive film properties: durability, adhesion to
organic substrates, reduced shrinkage, and reduced built-in
stresses
Ability to use heat-sensitive organic substrates
Potential for cure of composite structures
4-42
Supported Adhesive Film
Finished
Product
Self-supported Adhesive Film
h fi;:;,
I
1
H
-
1
f n U
Radiation
Processing
uv or EB-
I
Extrusio
Finished
Product
Figure 4-20.
Adhesive F i l m Systems
4-43
(g6)
High Energy Electrons
Nip
/
Secondary
Film Unwind
Impression Roll
Primary
Film
Unwind
\
Gravure
Roll
Figure 4-21.
Laminator Coater System
4-44
Rewind
(87)
Table 4-14
TYPICAL PRODUCTS PREPARED WITH A PLANAR CATHODE ELECTRON PROCESSOR (87)
Ad hes ive
Structure
R a d i a t i o n Curable Acrylic/Urethane
(A)
Low Density Polyethylene (LDPE)/SaranCoated Po 1y e s t e r s
Uncoated Polyester/LDPE
Oriented Nylon/LDPE
1.5 t o 2.0 Mrads
Voltage
155 KV
Bond Speed
(A)-800 g ( d e s t r u c t i v e ) ; (B)-50 g ( d e s t r u c t i v e )
(C)-1000 g ( d e s t r u c t i v e )
Web Strength
25 fpm
Nip Temperature
Room Temperature
Pan Temperature
Room Temperature
Gravure A p p l i c a t o r
300 L i n e quadrangular
Heat Seal Bond
6500 g/in.
Heat Seal Conditions
Temperature
350" F
Dwell Time
3 sec.
Psi
50
4-45
Table 4-15
ADHESIVE FILM APPLICATION AREAS (86,88)
Applications for Heat Activated
Adhesive Films
0
Decals, Labels, Nameplates
0
Garment Repair
0
Bookbinding
0
Carpet Underlay
0
Construction Panelling
0
Furniture Edge Veneer
0
Thermal Insulation
0
Multilayer Laminates
0
Platen Press (credit cards)
0
Protective and Decorative Sheets (printed patterns, metal 1 ized films, particle
board, furniture, wall components)
Upholstery
Applications and Structures for
Laminate Adhesive Films
0
Food Packaging
0
Film/Foil
0
Flexible Packaging (Non-food)
0
Fi lm/Foi 1/Fi lm
0
Film/Film
0
Paper
4-46
Mylar
wrapped
Silicone molded
integrated circuit
Plastic molded
pi..;:y
I
/
solder
maskant
EPOXY
Conform a I acry Iic
coating on entire
assembly
Teflon
sleeve
for wire
Epoxy staking
compound
Figure 4-22.
P r i n t e d Wiring C i r c u i t Board Showing Diverse
Uses o f P l a s t i c M a t e r i a l s (90)
4-47
R a d i a t i o n p r o c e s s i n g equipment used t o manufacture e l e c t r o n i c components and systems covers t h e e n t i r e e l e c t r o m a g n e t i c spectrum, such as I R , U V - v i s i b l e , e l e c t r o n
beam, plasma and X-ray wavelengths o f energy.
Use o f r a d i a t i o n p r o c e s s i n g o f mate-
r i a l s i n commercial e l e c t r o n i c devices i s growing a t an annual r a t e o f about 10 t o
25%.
The d r i v i n g f o r c e f o r u s i n g r a d i a t i o n p r o c e s s i n g over c o n v e n t i o n a l thermal
c u r i n g o p e r a t i o n s can be a t t r i b u t e d i n p a r t t o t h e f o l l o w i n g f a c t o r s :
S u p e r i o r p r o d u c t p r o d u c t i o n and performance c a p a b i l i t i e s .
Less f l o o r space r e q u i r e d f o r t h e equipment.
F a s t e r l i n e speeds.
Greater energy e f f i c i e n c y ( i t r e q u i r e s as much as 80 p e r c e n t
l e s s energy t o c o n v e r t f i l m s ) .
Fewer problems i n meeting government p o l l u t i o n r e q u i r e m e n t s
Higher f l a s h p o i n t s .
Conversion w i t h o u t d i s t o r t i o n o f h e a t - s e n s i t i v e s u b s t r a t e s .
Unique m a n u f a c t u r i n g f e a t u r e s .
The f o l l o w i n g paragraphs p r o v i d e a d i s c u s s i o n o f s e l e c t e d e l e c t r o n i c a p p l i c a t i o n s
where r a d i a t i o n c o n v e r s i o n i s b e i n g used.
I n some cases i t i s t h e major means o f
processing; i n o t h e r s i t i s o n l y b e g i n n i n g t o be used as a p r o d u c t p r o d u c t i o n
o p e r a t i on. (89,90 1
Integrated C i r c u i t s ( I C )
I n t e g r a t e d c i r c u i t s c o n t a i n t e n s o f thousands o f c i r c u i t elements and e l e c t r o n i c
components which p r o v i d e memory and l o g i c c a p a b i l i t i e s f o r devices r e q u i r e d by t h e
computer and communications i n d u s t r i e s .
The m a n u f a c t u r i n g process used t o prepare
t h e s e I C devices i n v o l v e s complex i n t e r r e l a t i o n s h i p s between m a t e r i a l s and f a b r i c a t i o n o p e r a t i o n s such as those shown i n F i g u r e 4-23.
F i l m formation i s through
thermal (800 t o 1200 C ) o x i d a t i o n processes t o f o r m s i l i c o n d i o x i d e o r chemical
vapor d e p o s i t i o n ( C V D ) t o produce s i l i c o n n i t r i d e s u r f a c e s .
I m p u r i t y doping i s
performed b y thermal d i f f u s i o n o f boron o r phosphorus, o r b y i o n i m p l a n t a t i o n .
L i t h o g r a p h y and e t c h i n g a r e used t o c r e a t e c i r c u i t s on s i l i c o n s u r f a c e s .
Mounting,
l e a d attachment, and e n c a p s u l a t i o n a r e t h e f i n a l processes r e q u i r e d t o manufacture
t h e i n t e g r a t e d c i r c u i t device.
The t h r e e areas o f most i n t e r e s t t o r a d i a t i o n p r o -
c e s s i n g a r e l i t h o g r a p h y , mounting, and e n c a p s u l a t i o n . (91,921
Lithography
L i t h o g r a p h y i s one o f t h e most i m p o r t a n t r a d i a t i o n processes u t i l i z e d b y t h e e l e c tronics industry.
L i t h o g r a p h y i s used t o d e f i n e v e r y s m a l l geometries o r
c o n n e c t i o n / i s o l a t i o n pathways r e q u i r e d i n I C m a n u f a c t u r i n g technology.
4-48
I n the
Single-Crystal
Silicon Slicer
*
SiO, or Si,N,
Film Formation
(Thermal or CVD)
Photo, E-Beam or
X-Ray Lithography
Etching
4
Impurity Doping
(Thermal Diffusion
or Ion Implantation)
1
P
cc)
2
I
I
cllii,
Placement
Into
Holder
,
*
Lead
Attachment
F
Encapsulate
-
Integrated
Current
L
Figure 4-23.
I
I
IC Manufacturing Process
(91)
process a s i l i c o n s l i c e i s s p i n coated w i t h a u n i f o r m t h i n f i l m o f r a d i a t i o n s e n s i t i v e polymeric material c a l l e d a r e s i s t .
I f t h e l i t h o g r a p h y i s t o be performed
o p t i c a l l y , t h e IC p a t t e r n i s f i r s t c r e a t e d on a mask which i s t h e n t r a n s f e r r e d t o
t h e r e s i s t v i a a number o f o p t i c a l techniques ( d i r e c t c o n t a c t p r i n t i n g u s i n g c o l l i mated sources o f UV o r v i s i b l e l i g h t ) o r o t h e r l i g h t p r o j e c t i o n t e c h n i q u e s ( F i g u r e
4-24).
L i g h t s e n s i t i v e r e s i s t s o r p h o t o r e s i s t s a r e g e n e r a l l y c l a s s i f i e d i n t o two groups;
n e g a t i v e and p o s i t i v e .
Negative p h o t o r e s i s t s i n v o l v e t h e c r o s s - l i n k i n g and g e l a -
t i o n o f t h e polymer, t h e r e b y p r o d u c i n g an i n s o l u b l e f i l m .
The t h r e e main compon-
ents incorporated i n a negative photoresist formulation are a chemically reactive
polymer, a p h o t o s e n s i t i v e agent, and a s o l v e n t .
t h e p r o d u c t i o n o f t h i s t y p e o f r e s i s t are:
Among t h e r e a c t i o n s i n v o l v e d i n
p h o t o c y c l o a d d i t i o n r e a c t i o n s (such as
t h e p h o t o c y c l o d i m e r i z a t i o n o f cinnamic a c i d s and i t s a l k y d e s t e r s 1, n i t r e n e react i o n s , and f r e e - r a d i c a l a d d i t i o n r e a c t i o n s (Table 3-4).
(42-1
A p o s i t i v e p h o t o r e s i s t makes use o f an i n c r e a s e i n a c i d i t y upon exposure t o r a d i a -
t i o n , t h e r e b y p r o d u c i n g a f i l m o f g r e a t e r s o l u b i l i t y i n a d i l u t e , aqueous base
solution.
The main components o f a p o s i t i v e p h o t o r e s i s t f o r m u l a t i o n a r e an a c i d i c
polymer, a p h o t o s e n s i t i v e i n h i b i t o r , and a s o l v e n t .
The two main t y p e s o f a c i d i c
polymers used i n t h e development o f p o s i t i v e p h o t o r e s i s t s a r e novolacs and
a c r y l ics
.
P o s i t i v e p h o t o r e s i s t s r e q u i r e l o n g e r exposure and more expensive m a t e r i a l s than
negative photoresists.
P o s i t i v e p h o t o r e s i s t s , however, have good c o n t r a s t and
r e s i s t s w e l l i n g d u r i n g development.
The image which i s produced on t h e s u b s t r a t e
i s t h e same as t h e image on t h e photomask.
q u i t e as c l e a r .
Negative p h o t o r e s i s t images a r e n o t
While t h e developer d i s s o l v e s t h e unexposed r e s i s t , i t a l s o causes
s w e l l i n g i n t h e exposed r e g i o n s .
The s w e l l i n g causes severe d i s t o r t i o n and en-
largement o f t h e image ( F i g u r e 4-25).
(42,931
Electron-beam d i r e c t p a t t e r n i n g can be performed w i t h o u t a mask b y u s i n g a c o n t r o l l a b l e electron-beam processor and an e l e c t r o n - s e n s i t i v e (degradable o r c r o s s l i n k a b l e ) r e s i s t m a t e r i a l ( F i g u r e 4-26).
L i t h o g r a p h y has a l s o been achieved w i t h
X-rays b y p r o j e c t i o n t h r o u g h a s p e c i a l mask i n c l o s e p r o x i m i t y t o t h e r e s i s t s u r f a c e ( F i g u r e 4-27).
The r e s o l u t i o n c a p a b i l i t i e s f o r each o f t h e f o u r l i t h o g r a p h y
system i s g i v e n i n Table 4-16.
(94)
4-50
Mirror or
Reflector
Filter and Condenser
Lens System
\
I
Mask
I
-
Reduction Lens
System
\
Wafer
F i gure 4-24.
Lithography Process
4-51
(92)
Light
Illuminated
Areas
a
x
Silicon Dioxide
Silicon Substrate
Negative Resist:
Positive Resist:
a Rendered Insoluble nRendered Soluble
1
1
B
................................
I
Etched Film Patterns:
F i g u r e 4-25.
Schematic o f C o n t a t t P r i n t i n g
U s i n g P o s i t i v e and Negative R e s i s t s (92,93)
4-52
Electron Gun
X-Y Mask
Data
and
Computer
ControI
/ Deflection Coils
0 I
e-
f
Figure 4-26.
Electron-Beam Patterning System
4-53
(92)
x-ray
Target
Electron Beam
Mask Absorber
Resist
Wafer
Figure 4-27.
X-Ray Lithography System
4-54
(92)
Table 4-16
PHOTOLITHOGRAPHIC PROCESSES
Lithography
Resolution
System
Optical
uv
A
(94)
Present
Future
1.5 p m
0.75 p m
0.5
0.25
pm
X-ray
1000 R
100 W
Scanned
E Beam
1000 W
(10 8)
5 R
pm
= angstrom o r 10-8 cm
When t h e l i t h o g r a p h y process i s completed, t h e wafer has been s u b j e c t e d t o s e v e r a l
c y c l e s o f exposure, e t c h i n g , washing, doping, and baking; and i t may c o n t a i n as
many as 500 i n t e g r a t e d c i r c u i t s o r c h i p s .
The wafer i s then c u t i n t o i n d i v i d u a l
c h i p s , each o f which i s t e s t e d by a computerized probe.
A 10% y i e l d o f w o r k i n g
c h i p s i s c o n s i d e r e d good f o r a new c h i p i n i t s f i r s t p r o d u c t i o n r u n .
Adhes ives and Encapsu 1a n t s
Once a c h i p has been t e s t e d i t can be a t t a c h e d t o a leadframe ceramic package
t h r o u g h t h e use o f e l e c t r i c a l l y c o n d u c t i v e adhesives o r nonconductive adhesives.
F i g u r e 4-28 i s a schematic o u t l i n e f o r c h i p placement on a board s u r f a c e u s i n g
c o n d u c t i v e o r nonconductive adhesive systems.
P r o p e r t i e s o f two adhesive systems
( c o n v e n t i o n a l , thermal and U V ) a r e d e s c r i b e d i n Table 4-17 and c e r t a i n s u r f a c e
mounting d e v i c e r e q u i r e m e n t s a r e g i v e n i n Table 4-18.
Encapsulants used i n t h e e l e c t r o n i c s i n d u s t r y a r e p r i m a r i l y epoxy and s i l i c o n - b a s e d
polymer systems, a l t h o u g h urethanes and a c r y l i c s can be used t o some degree i n
these applications.
Encapsulants a r e p r i m a r i l y a p p l i e d i n a m o l d i n g o p e r a t i o n o r
f i l l i n g o p e r a t i o n and a r e u s u a l l y t h e r m a l l y c u r e d r a t h e r than r a d i a t i o n processed,
a l t h o u g h p h o t o c u r a b l e epoxy r e s i n s m i g h t be c o n s i d e r e d f o r c e r t a i n p o t t i n g o r encapsulation operations.
(95)
4-55
UV Preirradiation
,-
P
I
am
m
-B-rCl-
ul
cn
Adhesive
Dispensing
Chip
Placement
Figure 4-28.
i l
I
I
Ultraviolet
Curing
/
&-fi-!25
PC-Board
Inversion
Insertion of
Conventional
Components
Fluxing,
Soldering,
and Cleaning
Automation of Surface-Mounted Boards
1 ,
I
Table 4-17
PROPERTIES OF TWO STAKING COMPOUNDS FOR SMD
THERMAL VERSUS U V CURABLE MATERIALS (90,91 ,95)
Thermal
uv
EPOXY
Epoxy acrylate
70,000-600,000 CP
60,000-300,000 CP
1.19
1.2
Gap filling
Up to 0.010 in.
up to 0.010 in.
Cure times
Infrared
Oven
90 sec 8 150OC
10 min 8 1OOOC
--
90 sec 8 15OOC
-15 sec 8 2000CW/in.
Cured Properties
Shore hardness
Chip shear strength
Max. temperature resistance
Solvent resistance
850
>10 lb
255OC - 15 sec
Good
850
>10 lb
255OC - 15 sec
Good
Electric Properties
Volume resistivity 8 25OC
Breakdown voltage
Dielectric constant
1 x 1016 ohm-cm
2000 V/mil
g3.5
1 x 10l2 ohm-cm
>1500 V/mil
z4
Composition
Viscosity
Specific gravity
uv
Note:
Surface Mount Device (SMD)
4-57
Table 4-18
ADHESIVES SURFACE MOUNTING D E V I C E (SMD) REQUIRENENTS (90,91 , 9 5 )
SMD Attach Using Conductive Adhesive
Screen p r i n t adhesive
Pick and place components
Cure (1-15 minutes)
Test and rework components
SMD Adhesives
-
Nonconductive
The d o t s i z e must stand a t l e a s t 0.006 i n c h h i g h
The d o t cannot f l o w and spread t o t h e solder path
When t h e c h i p i s placed, t h e adhesive must have "tack", i.e.,
i t must
h o l d t h e chips i n place through movement i n t h e p r o d u c t i o n l i n e
The adhesive must hold t h e c h i p i n place d u r i n g t h e s o l d e r o p e r a t i o n
SMD A t t a c h Using Solder
Apply s o l d e r
P r e - t i n components
Dispense nonconductive adhesive
Pick and p l a c e components
Cure adhesive
Prebake (80°C f o r 30 minutes)
Solder r e f l o w (210°C t o 250°C f o r 30 t o 60 seconds)
Clean boards, remove f l u x (2-4 minutes)
Test and rework components
Note:
Surface Mount Device (SMD)
4-58
P r i n t e d C i r c u i t Boards
P r i n t e d c i r c u i t boards (PCB) can be manufactured u s i n g t h r e e t y p e s o f p h o t o r e s i s t
products:
screen p r i n t i n g i n k s , l i q u i d p h o t o r e s i s t s , and d r y f i l m l a m i n a t i o n
photoresists.
U l t r a v i o l e t r a d i a t i o n c u r a b l e screen p r i n t i n g i n k s a r e p r o j e c t e d t o
p l a y a more s i g n i f i c a n t r o l e than t h e o t h e r two p h o t o r e s i s t t e c h n i q u e s i n t h e
f u t u r e f a b r i c a t i o n o f p r i n t e d c i r c u i t boards.
The m a j o r t y p e s o f p r i n t e d c i r c u i t
boards o f i n t e r e s t t o t h e e l e c t r o n i c s i n d u s t r y a r e d e s c r i b e d i n T a b l e 4-19.
The
t y p e s o f screenable p h o t o r e s i s t u l t r a v i o l e t c u r a b l e o r t h e r m o s e t t i n g i n k s used i n
PCB f a b r i c a t i o n a r e (1) imaging r e s i s t s , ( 2 ) e l e c t r i c a l l y c o n d u c t i v e i n k s , ( 3 )
s o l d e r masks, ( 4 ) masking i n k s , and ( 5 ) conformal c o a t i n g s . (68,891
Imaging o r p a t i n g r e s i s t s a r e used t o c r e a t e c i r c u i t pathways and p r o t e c t s p e c i f i c
areas on t h e PCB f r o m chemical o r e l e c t r o c h e m i c a l e t c h i n g processes.
These r e s i s t s
a r e designed t o be removable a f t e r t h e e t c h i n g o r p l a t i n g s t e p has been completed.
E l e c t r i c a l l y c o n d u c t i v e i n k s can be used t o c r e a t e c i r c u i t s d i r e c t l y w i t h o u t having
t o be imaged o r etched.
I n a new PCB f a b r i c a t i o n process t h e c i r c u i t p a t t e r n i s
p r i n t e d d i r e c t l y o n t o a t r a n s f e r paper b y a screen o r g r a v u r e process u s i n g an
e l e c t r i c a l l y c o n d u c t i v e t h e r m a l l y cured i n k system.
T h i s p a t t e r n e d t r a n s f e r paper
s u b s t r a t e i s t h e n overcoated w i t h an adhesive, i n s e r t e d , and t r a n s f e r r e d t o t h e PCB
substrate.
Removal o f t h e paper leaves a m e t a l - r i c h s u r f a c e a t t h e t o p o f t h e PCB
which i s immediately a c c e s s i b l e f o r s o l d e r i n g o r e l e c t r o p l a t i n g processes. (96
A
97)
S o l d e r masks a r e p r o t e c t i v e c o a t i n g s a p p l i e d t o c i r c u i t boards b y s c r e e n i n g t e c h niques t o mask e l e c t r i c a l conductor t r a c k s f r o m t h e s o l d e r i n g o p e r a t i o n .
c u r e d f i l m s remain as a permanent p a r t o f t h e c i r c u i t board assembly.
These
Masking
i n k s , u n l i k e t h e o t h e r screen i n k systems, have no e l e c t r i c a l f u n c t i o n on t h e
f i n i s h e d board and a r e o n l y used t o mark l o c a t i o n s f o r t h e i n s e r t i o n o f c i r c u i t
components , dates , s e r i a l numbers, e t c .
Conformal c o a t i n g s , however , p r o v i d e e l e c -
t r i c a l i n s u l a t i o n f o r t h e e n t i r e PCB and o f f e r b a r r i e r p r o t e c t i o n f r o m t h e e n v i r o n ment.
The t r e n d f o r t h e PCB f a b r i c a t i o n i n d u s t r y i s t o use more UV-curable
materials.
A sumnary o f i m p o r t a n t p r o p e r t i e s o r r e q u i r e m e n t s f o r some o f t h e major
screen i n k systems a r e g i v e n i n Table 4-20.
(68,98,99)
Fiber Optics
There has been a major impact on t h e e l e c t r o n i c s and communications i n d u s t r y due t o
f i b e r optics technologies.
F i b e r o p t i c s a r e l i g h t w e i g h t , v e r y s m a l l , and compact
and p r o v i d e i n t e r f e r e n c e - - f r e e communication between computers and p e r i p h e r a l s .
F i b e r o p t i c s have low a t t e n u a t i o n and can t r a n s m i t a l a r g e amount o f i n f o r m a t i o n
4-59
Table 4-19
MAJOR TYPES OF PRINTED CIRCUIT BOARDS
PCB
Print-and-etch
single sided
Description
Copper circuitry on phenolic
1 ami na te
(E)
Application
Low cost, low quality for
radio, television telecommunications and appliance
industries
-~~~
Plated-through-hole Double-sided or multilayered
tin/lead, nickel, or gold
plated circuitry
Military and computer
applications
F1 exi bl e
Si ng 1e-s i ded or p 1 ated-through- Automotive and
telecommunications
hole with copper or tin/lead
circuitry on polyester or
polyimide base laminate films
Additive
Addition o f copper circuitry
directly onto a treated
laminate substrate
4-60
High volume consumerrelated products
- -.
Table 4-20
PROPERTIES OF SCREEN I N K SYSTEMS
(68)
Solder Masks
.-.
--
Rapid setting radiation curable acrylic or epoxy resins
Screenabi 1 i ty
Abrasion resistance
__ --Flexibility
Adhesion to copper, tin/lead, nickel and gold
Flame resistance
Machinabi 1 i ty
Low water absorption
High gloss or cosmetic appearance where desired
Chemical and solvent resistance
Resistance to soldering and desoldering
Inks and Marking Coatings
Low odor
High rub and abrasion resistance
Very high gloss where desired
Nontoxic (oral)
Low coefficient of friction
Nonyel 1 ow f i lm
High flexibility
Low skin irritation
Low curing temperatures (radiation curable)
Conformal Coatings
Low moisture absorption and permeabi 1 i ty
High resistivity and dielectric strength
Abrasion resistance
Strippability for easy repair
Solderabi 1 i ty
Good chemical resistance
Short cure time
Room temperature cure
Easy application
Good pot and shelf life
Nonpol 1 uti ng
Si ngle-component formul ati ng
Transparency
Low cost
4-61
over longer distances w i t h longer repeater spacing than conventional copper wire
telephone cables. (100,101) Optical f i b e r s can be manufactured and coated with a
UV curable protective f i n i s h in an apparatus similar t o the one shown in Figure
4-29. The radiation ( U V ) curable coatings used t o coat the optical fiber must be
capable of preserving the optical c h a r a c t e r i s t i c s and strength of the f i b e r , and
protect against mechanical damage and moisture penetration. The use of radiation
curable coatings f o r optical f i b e r s i s growing a t a rapid r a t e b u t the actual
volume of coating i s very small; 1 mile of optical f i b e r weighs only 25
-
grams
( 102 ,103 1
Magnetic and Optical Media
Radiation processing technology o f f e r s an improved method of manufacturing magnetic
and optical systems f o r the electronics and communications i n d u s t r i e s . Even though
magnetic and optical media may compete f o r similar market areas, the use of some
form of electromagnetic radiation i n t h e manufacturing process s t i l l appears t o be
a constant f a c t o r f o r b o t h technologies.
Magnetic Media. Magnetic media products fa1 1 i n t o several general categories such
as audio, video, computer and instrument types and f l e x i b l e or r i g i d disks. The
current manufacture of magnetic media by radiation processing (almost exclusively
E B ) techniques has been driven by t h r e e important f a c t o r s : (104,105)
0
Conventional thermally s e n s i t i v e urethane binder r e s i n s are
slow t o cure and r e s u l t in products t h a t are sometimes even
undercured and could not perform up t o t h e i r rated
s p e c i f i c a t i o n s . Moisture entrapment in the product and the
necessity t o s e t aside r o l l s of coated films f o r two weeks
i n order t o advance t h e curing reaction t o a s t a t e of
completion were some of the other undesirable f a c t o r s of
conventional coatings as applied t o t h i s industry. The
instantaneous and complete curing of a acryl ate/urethane binder
by EB processing techniques i s a much more c o n t r o l l a b l e
manufacturing method over t h a t of the conventional moisture
cure polymer binder systems.
0
Reduced wear of the coating and calendering equipment was noted
with EB cure coating as compared w i t h conventional coating
systems.
This led t o a potential payback in one year f o r a
high production r a t e EB f a c i l i t y .
e
Chromium dioxide i s very s e n s i t i v e t o the h i g h temperatures
which were required t o form r i g i d disk configurations. Room
temperature EB curing permits the greater use of t h i s special
magnetic pigment and a processing speed of 500 t o 1000 f e e t per
minute a t 5 t o 10 Mrad energy dose requirements (Figure
4-30). (105)
-
4-62
Glass - Preform
-. ..
.
.
.-.
/
. . . . ... .
Furnace
vDiameter
c3
Coating Applicator
Monitor
Coating Material
I
on I
UV-Curing Lamp System
I
I
I
I
I
-t
Figure 4-29.
Coated and Cured Fiber
UV Coating o f Optical Fibers
4-63
(103)
I
m
P
Unwind
Rewind
Figure 4-30.
Magnetic Media Coating Line w i t h EB Cure
(105)
O p t i c a l Media.
Recent developmcnts i n l a s e r technology have l e d t o t h e i n c o r p o -
r a t i o n o f s o p h i s t i c a t e d o p t i c a l m a t e r i a l s and systems i n e l e c t r o n i c d e v i c e s f o r t h e
communications and home market p r o d u c t areas.
These devices i n c l u d e l a s e r - r e a d a b l e
v i d e o i n f o r m a t i o n c a r r i e r s (Laser V i s i o n ) , l a s e r - r e a d a b l e audio i n f o r m a t i o n c a r r i e r s (Compact D i s c ) , d a t a s t o r a g e f o r computer a p p l i c a t i o n s ( d i g i t a l o p t i c a l
r e c o r d i n g ) , compound Senses o r a s p h e r i c a l lenses ( o p t i c a l l e n s e s ) , and o p t i c a l d a t a
t r a n s p o r t systems ( o p t i c a l f i b e r s and waveguides).
The advantage o f o p t i c a l sys-
tems over t h e i r metal conductor analogs can be shown i n Table 4-21.
__
- ___ -
(106) The
o p t i c a l devices have a much g r e a t e r frequency r a n g e - t r a n s m i s s i o n c a p x i t y w i t h v e r y
low l o s s of a t t e n u a t i o n p r o p e r t i e s when compared w i t h o t h e r methods used f o r d i r e c t
s i g n a l coup1 i n g o f e l e c t r o n i c i n f o r m a t i o n .
Table 4-21
COMPARISON OF VARIOUS MEANS OF TRANSMISSION
Transmission Type
Wire P a i r
Coaxi a1 Cable
Waveguide
Optical Fiber
(106)
Frequency Range (kHZ
A t t e n u a t i o n (dB/km)
1-140
0.06-51 x 10'
<50 x l o 6
loll
0.1-0.3
59
0.5-4
<1.O-800
One o f t h e most i m p o r t a n t new areas o f o p t i c a l r e l a t e d communication devices i s t h e
o p t i c a l "video disc".
About t h e s i z e o f a l o n g - p l a y i n g audio r e c o r d , t h e p i c t u r e
and sound i n f o r m a t i o n i s r e c o r d e d on i t as a succession o f s m a l l depressions o f
v a r i a b l e l e n g t h and r e p e t i t i o n frequency.
The i n f o r m a t i o n i s sensed o p t i c a l l y w i t h
a helium-neon l a s e r (632.8 nm) b y t h e p l a y e r i n such a manner t h a t t h e read-out
system does n o t come i n d i r e c t p h y s i c a l c o n t a c t w i t h t h e d i s c .
The o p t i c a l d i s c
i s manufactured i n t h e f o l l o w i n g manner:
0
P r e p a r a t i o n o f a m e t a l master mold ( u s i n g p h o t o r e s i s t o r
photo1 it h o g r a p h i c p r o c e s s i n g techniques 1.
0
A p p l i c a t i o n o f a UV-curable c o a t i n g o r adhesive t o t h e c e n t e r
of t h e m e t a l mold.
0
Deformation ( s l i g h t bending) o f a t r a n s p a r e n t p l a s t i c d i s c
(polymethylmethacrylate, p o l y v i n y l c h l o r i d e , o r p o l y c a r b o n a t e )
t o make i t convex, and a p p l i c a t i o n o f t h e r a d i a t i o n c u r a b l e
adhesive f o r u n i f o r m spreading over t h e m e t a l master mold
s u r f ace.
4-65
a
Exposure o f t h e r a d i a t i o n - c u r a b l e c o a t i n g o r adhesive t o UV
l i g h t (365 nm) and p o l y m e r i z i n g t h e l i q u i d system i n t o a r i g i d
film.
a
S e p a r a t i o n o f t h e s u b s t r a t e and cured c o a t i n g f r o m t h e mold
f o l l o w e d by m e t a l i z a t i o n ( m i r r o r f o r m a t i o n ) and f i n a l c o a t i n g
(UV r a d i a t i o n c u r a b l e , plasma c o a t i n g s o r c o n v e n t i o n a l
low-temperature a i r dry-cured c o a t i n g system) f o r p r o t e c t i o n
f r o m a b r a s i o n and h a n d l i n g o p e r a t i o n s .
A diagram d e p i c t i n g t h e major o p e r a t i o n s a s s o c i a t e d w i t h v i d e o d i s c manufacture
__
_.
._.
-.
-
i s shown i n F i g u r e 4-31.
Many o f t h e r a d i a t i o n p r o c e s s i n g concepts developed f o r
present-day v i d e o d i s c s can be u t i l i z e d f o r f u t u r e manufacture o f new o p t i c a l
r e c o r d i n g systems and devices. (107,108)
PLASTICS AND RUBBER MATERIALS
C u r r e n t r a d i a t i o n p r o c e s s i n g o f p l a s t i c s i s m a i n l y i n v o l v e d w i t h h i g h energy
e l e c t r o n - i n d u c e d c r o s s - l i n k i n g of p o l y e t h y l e n e and p o l y v i n y l c h l o r i d e f o r foam
s t a b i l i z a t i o n , w i r e i n s u l a t i o n , and heat s h r i n k a b l e f i l m s o r t u b i n g a l t h o u g h o t h e r
v i n y l t y p e s of polymers can a l s o be c r o s s - l i n k e d i n a s i m i l a r manner t o produce
u s e f u l p r o d u c t s ( T a b l e 4-22 1.
High energy e l e c t r o n r a d i a t i o n p r o c e s s i n g i s used i n t h e w i r e and c a b l e i n d u s t r y t o
improve t h e p r o p e r t i e s of t h e i n s u l a t i n g p l a s t i c m a t e r i a l s .
One o f t h e major
b e n e f i t s o f r a d i a t i o n p r o c e s s i n g i s t h e i n c r e a s e d thermal s t a b i l i t y and toughness
o f t h e i r r a d i a t e d polymer over t h a t o f a c o n v e n t i o n a l u n c r o s s - l i n k e d i n s u l a t i o n
m a t e r i a l ( T a b l e 4-23).
The most i m p o r t a n t f e a t u r e a s s o c i a t e d w i t h high-energy
e l e c t r o n r a d i a t i o n p r o c e s s i n g o f w i r e and c a b l e i n s u l a t i o n m a t e r i a l s i s t h e f a c t
t h a t t h e depth o f e l e c t r o n p e n e t r a t i o n i n a g i v e n i n s u l a t o r i s a d i r e c t f u n c t i o n o f
e l e c t r o n energy and i n v e r s e l y r e l a t e d t o t h e s p e c i f i c g r a v i t y o f t h e m a t e r i a l .
For
example, a 0.020 - i n c h t h i c k n e s s o f r a d i a t i o n c u r a b l e PVC having a s p e c i f i c g r a v i t y
v a l u e o f 1.3 would r e q u i r e 200 kV o f e l e c t r o n energy f o r f u l l p e n e t r a t i o n ; a 0.045i n c h t h i c k sample would r e q u i r e 500 kV f o r p e n e t r a t i o n ; and a 0.090-inch
sample o f t h e same m a t e r i a l would r e q u i r e 1 MeV.
thick
The i n v e r s e r e l a t i o n s h i p between
s p e c i f i c g r a v i t y and depth o f e l e c t r o n p e n e t r a t i o n a t c o n s t a n t v o l t a g e i s shown i n
Table 4-24.
F i g u r e 4-32.
A t y p i c a l electron-beam p r o c e s s i n g s e t up f o r w i r e l c a b l e i s shown i n
T h i s t y p e o f r a d i a t i o n p r o c e s s i n g o p e r a t i o n can m o d i f y w i r e p r o d u c t s
a t speeds o f 500 t o 3,000 f t l m i n ( s i x EB a c c e l e r a t o r s can manufacture 5.23 b i l l i o n
f t l y e a r based on speeds o f 12,000 f t l m i n ,
22 h r l d a y f o r 330 d a y l y r ) w i t h 10 t o 20
mA beam c u r r e n t s o r dose values r a n g i n g from 1 t o 10 Megarads.
Wire and c a b l e
i n s u l a t i o n can a l s o be c r o s s - l i n k e d c h e m i c a l l y through t h e use of peroxides, mois-
4-66
Molding
MO
Exposure
Separation
MO
Imaging
MO: Mold; L: Liquid Layer; S: Substrate;
M: Mirror; P: Protective Layer.
F i g u r e 4-31.
F a b r i c a t i o n o f L a s e r v i s i o n Video D i s c s
4-67
(107,108)
Table 4 - 2 2
SELECTED APPLICATION AREAS FOR IRRADIATED POLYMER MATERIALS (109)
ADD1 i c a t i ons
Pol Ymers
Polyethylene
Hookup wire
Automotive wire
Appliance and fixture wire
Business machine wire
Computer control cabl e
Nuclear power s t a t i o n control cable
Low voltage power cable
A i r c r a f t and aerospace wire
Polyvinyl chloride
Hookup wire
F1 a t ribbon cabl e
High voltage lead wire
Computer back panel wire
Tel ephone wire
Motor lead wire
Propropyl ene
Polyamide
Polyvinyl idene f l u o r i d e
Ethylene fluorocarbon copolymer
F1 uoropolymer
Ethyl vinyl a c e t a t e
Thermoplastic polyimide
Chlorinated polyethylene
Neoprene
Butyl
Si1 icone elastomer
F1 uoroel astomer
Ethyl ene propylene rubber
Polyurethane
Shrinkable tubings
Shrinkable p a r t s
Shrinkable tapes
D i e l e c t r i c rod and sheet forms
Wire insulation and jacketing
4-68
-~
Table 4-23
COMPARISON OF PHYSICAL PROPERTIES FOR CONVENTIONAL 105O C
PVC AND IRRADIATED PVC WIRE COMPOUNDS (109)
Physical Propertv
Conventional 105O C PVC
P r o p e r t y Values
I r r a d i a t e d PVC
P r o u e r t v Values
Tensile strength
3,000 p s i
3,000 p s i
E l ongat ion
250%
200%
Solder i r o n resistance:
Time t o f a i l @ 660° F,
1.5 l b . l o a d
t l second
Insulation resistance:
Megohms/l ,000 ft
>1,000
.
Cut-thru resistance:
Time t o c u t - t h r u @ 105O C,
.005" c h i s e l
<5 seconds
Heat r e s i s t a n c e :
% retention o f elon ation
a f t e r 168 h r s @ 136 C
50
%
4-69
>300 seconds
>1,000
>600 seconds
75
Table 4-24
EFFECT OF SPECIFIC GRAVITY OF A MATERIAL ON THE DEPTH OF
ELECTRON BEAM PENETRATION AT TWO ELECTRON ACCELERATOR VOLTAGES
(0.3 AND 1 MeV)
(109)
Specific
Gravity
Accel e r a t o r
Voltage (MeV)
Depth of Beam
P e n e t r a t i o n ( inches 1
1.o
1
0.12
1.3
1
0.09
1.8
1
0.06
1.o
0.3
0.04
1.3
0.3
0.03
1.8
0.3
0.02
4-70
Electron Scanner
Electron
Beam
;
Wire In
Wire Out
Side View
Electron Scanner
Wire Out
I
Wire In
U
U
Top View
Figure 4-32.
W i re-Cab1 e
Electron-Beam Processing System f o r
(109)
4- 71
t u r e , and thermal (steam o r d r y n i t r o g e n ) p r o c e s s i n g manufacturing equipment.
There are s e v e r a l d i s t i n c t advantages t o t h e high-energy e l e c t r o n r a d i a t i o n process
over those a s s o c i a t e d w i t h c o n v e n t i o n a l thermal c u r i n g techniques, b u t t h e r e a r e no
i n s u l a t i o n t h i c k n e s s r e s t r i c t i o n s w i t h t h e c o n v e n t i o n a l system as i s t h e case f o r
r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s (Table 4-25).
Two o t h e r areas o f i n t e r e s t i n v o l v i n g commercial r a d i a t i o n p r o c e s s i n g o f p l a s t i c s
m a t e r i a l s a r e c r o s s - l i n k e d p o l y e t h y l e n e foams and s h r i n k a g e packaging m a t e r i a l s o r
t u b i n g ( p o l y o l e f i n s ) f a r f a o d and w i r e connector a p p l i c a t i o n s .
C r o s s - l i n k e d p o l y e t h y l e n e foams a r e u s u a l l y expanded 10 t o 40 t i m e s t h e i r o r i g i n a l
volume; t h e y a r e manufactured b y b o t h e l e c t r o n beam i r r a d i a t i o n and chemical
c r o s s - l i n k i n g methods.
These m a t e r i a l s have d e s i r a b l e q u a l i t i e s f o r commercial use
because o f t h e i r r e s i l i e n c y , c l o s e d c e l l c o n s t r u c t i o n , and t h e i r a b i l i t y t o be
thermofonned i n t o a wide v a r i e t y o f shapes and c o n f i g u r a t i o n s .
P o l y e t h y l e n e foam
( c r o s s - l i n k e d and n o n c r o s s - l i n k e d ) i s a s p e c i a l t y polymer w i t h a usual consumption
of about 25,000 m e t r i c tons; consumption i s growing a t an annual r a t e o f about
15 percent.
The c r o s s - l i n k e d polymer comprises a p p r o x i m a t e l y 50 p e r c e n t o f t h e
t o t a l commercial p o l y e t h y l e n e foam market.
H a l f o f t h i s c r o s s - l i n k e d foam i s made
t h r o u g h t h e use o f i o n i z i n g r a d i a t i o n f r o m e l e c t r o n a c c e l e r a t i o n i n t h e 500 kV t o 4
MeV range; t h e o t h e r h a l f uses o r g a n i c p e r o x i d e s .
Both t e c h n i q u e s a r e growing i n
use more i n accordance w i t h t h e f e a t u r e s o f t h e foaming process r a t h e r t h a n t o t h e
method o f c r o s s - l i n k i n g m a n u f a c t u r i n g p r o c e s s i n g o p e r a t i o n s .
These foam m a t e r i a l s
a r e used f o r gaskets, f l o o r backing, mounting tapes, and consumer goods such as
e x e r c i s e o r camping mats, t o y s , l i n e r s , b r a cups, and o r t h o p e d i c s u p p o r t
m a t e r i d l s . (110)
The CRYOVAC D i v i s i o n o f W. R. Grace and Company manufactures r a d i a t i o n processed
h e a t - s h r i n k a g e p l a s t i c f i l m s and bags f o r t h e vacuumized packaging o f f o o d products.
I n t h i s t e c h n o l o g y a p o l y o l e f i n preform o r tube i s extruded, t h e n i r r a d i a t e d
w i t h high-energy e l e c t r o n s (500 kV t o 2 MeV scanning e l e c t r o n beam processor, 25 mA
beam c u r r e n t s , 18 i n c h sweep p a t h ) , b i a x i a l l y o r i e n t e d v i a a blown f i l m - t r a p p e d
bubble process, and made i n t o bags o r s l i t and s o l d as f i l m .
Irradiated polyole-
f i n s have a memory e f f e c t such t h a t upon h e a t i n g t h e f i l m o r t u b i n g s h r i n k s causing
a secure f i t around p r o d u c t s c o n t a i n e d w i t h i n i t s surfaces.
Raychem developed a
s i m i l a r process f o r i r r a d i a t i n g p o l y o l e f i n t u b i n g f o r c o n n e c t i n g w i r e s o r a p p l y i n g
permanent marking l a b e l s t o w i r e end connectors v i a h e a t s h r i n k i n g - b o n d i n g
techniques.
(111)
4-72
Table 4-25
COMPARISON OF CHEMICAL VULCANIZATION VERSUS IRRADIATION PROCESSING (2)
Chemical Vu 1 cani zati on
Irradiation Processina
$150,000 installation cost-less,
$150,000 installation cost, turnkey
if boiler avai 1 able
avai 1 able
Special extrusion equipment
required
No special extrusion equipment
Critical extrusion conditions
Noncritical extrusion conditions
High-pressure steam and cooling
auxi 1 i ari es
No auxiliary requirements:
integrated system
High scrap on start-up
Economica1 start-up
Low-to-medium speed, no wall
thickness limitation
High-speed, wall thickness
limitation
Space-consuming 300-500 ft
steam and cooling troughs
Compact, no troughs
Heat , steam environment/
safety factors
Ozone , irridation environmental/
safety factors
4-73
High-energy e l e c t r o n r a d i a t i o n processes can a l s o be used t o improve t h e p r o p e r t i e s
o f e l a s t o m e r i c o r rubber m a t e r i a l s used i n t h e manufacture o f conveyor b e l t s ,
r u b b e r c a b l e i n s u l a t i o n , and t i r e s . (112)
The g r e a t e s t volume use o f r a d i a t i o n
( e l e c t r o n beam) p r o c e s s i n g technology i s i n t h e t i r e i n d u s t r y , which consumes most
of t h e n a t u r a l l y o c c u r r i n g and s y n t h e t i c elastomers produced i n t h e
-
U.S. t o d a y
~
( T a b l e 4-26).
(113)
~
I n t h e t i r e m a n u f a c t u r i n g process t h e i n n e r l i n e r s , body p l i e s , t r e a d s t a b i l i z e r
p l i e s , s i d e w a l l s , and o t h e r t i r e components can be i r r a d i a t e d w i t h high-energy
e l e c t r o n s p r i o r t o t h e i r assembly i n t o t h e t i r e .
The c r o s s - l i n k i n g induced b y t h i s
t r e a t m e n t improves t h e f o r m s t a b i l i t y o f t h e s e m a t e r i a l s d u r i n g t h e c o n s t r u c t i o n ,
molding, and subsequent thermal v u l c a n i z a t i o n o r c u r i n g o f t h e t i r e composite
system.
The i r r a d i a t i o n process improves gage r e t e n t i o n o f t h e t i r e components i n
t h e f i n a l p r o d u c t such t h a t an o v e r a l l r e d u c t i o n i n t h i c k n e s s o f one o r more o f t h e
f u n c t i o n a l l a y e r s can be achieved.
This equates t o an o v e r a l l savings i n m a t e r i a l s
and p r o v i d e s an economic i n c e n t i v e f o r t h e use o f i r r a d i a t i o n p o s t t r e a t m e n t o f
calendered o r e x t r u d e d p a r t s o f t h e t i r e .
F u r t h e r examples o f r a d i a t i o n t r e a t m e n t
of elastomers f o r improved t i r e and r e l a t e d p r o d u c t s a r e shown i n Table 4-27.
(112)
-
PLASMA PROCESSING
Low-temperature plasma r a d i a t i o n i s a new t o o l f o r t h e commercial p r o c e s s i n g o f
polymer p r o d u c t s .
Plasma-processing o f f e r s a clean, f a s t ,
and s a f e method o f p r e -
p a r i n g polymer s u r f a c e s f o r bonding, p r i n t i n g , p o t t i n g , c o a t i n g , and m e t a l i z i n g .
Conventional methods f o r p r e p a r i n g polymer s u r f a c e s can be d i v i d e d i n t o two c a t e gories:
wet and d r y .
Wet p r o c e s s i n g uses a s o i v e n t t o remove grease and o t h e r
contaminants f o l l o w e d b y t r e a t m e n t w i t h a chemical t h a t etches o r o x i d i z e s t h e
polymer s u r f a c e .
Dry processes i n c l u d e t h e use of corona discharges, gas flames,
and mechanical a b r a s i o n t o a l t e r a polymer surface.
A l l o f these c u r r e n t tech-
niques have c e r t a i n drawbacks (hazardous, l i m i t e d usefulness, o r r e s t r i c t e d t o
c e r t a i n polymer c l a s s e s ) which can many t i m e s be overcome through u t i 1 i z a t i o n o f
plasma-processing t e c h n o l o g i e s .
A comparison o f plasma e t c h i n g o f polymer s u r f a c e s
w i t h o t h e r methods o f polymer s u r f a c e m o d i f i c a t i o n s w i t h r e g a r d t o adhesive bond
s t r e n g t h development i s shown i n Table 4-28.
4-74
(119)
Table 4-26
RUBBER MARKET DISTRIBUTION
Products
(113)
Percent
T i r e s and t i r e p r o d u c t s
65
N o n t i r e products
Footwear
1
Belts, b e l t i n g
1
Hose, t u b i n g
2
Sponge r u b b e r products
Foam r u b b e r p r o d u c t s
1.1
3
F l o o r and w a l l c o v e r i n g
0.4
O-rings, packing, gaskets
2
Pressure-sensitive tape
0.6
Industrial r o l l s
0.6
Automotive molded goods
5
Other molded goods
6
M i 1 it a r y goods
0.5
Shoe p r o d u c t s
1.6
Drugs, medical s u n d r i e s
0.5
Coated f a b r i c s
1.3
Thread ( b a r e )
0.5
Sol v e n t and 1a t e x cement
1.5
Toys, b a l l oons
0.4
A t h l e t i c goods
0.6
Wire, c a b l e
1.1
Other
4.3
Total n o n t i r e products
35
100
4- 75
.
_ .
Table 4 - 2 7
APPLICATIONS FOR RADIATION PROCESSED ELASTOMERIC MATERIALS
ADD^ i cati on
(112)
Reference
Irradiation of radial body plies with 500 KeV
electrons to doses between 1 and 5 M rads in
combination with radial tensile strains o f 1
to 7 percent applied during single stage expansion of a tire eliminated wrinkling or
waviness of the reinforcing tire cords.
114
Irradiat i on of i nnerl i ners, pl ies, bead cores
and treads improves the dimensional stabil ity
of the above tire components.
115
Extrusion of rubber strips into a moving mold
followed by embossing a design in the rubber
then stripping it from the mold and irradiate
to produce a product useful in floor mats or
precured treads useful in retreading of tires.
116
Radiation induced degradation of multilayer
ti re rubber (polyisobutyl ene) inner1 i ners
combined with other materials to produce
puncture sealant composite structures.
117
Reduction of unsightly rubber projections
such as vents and flash materials on the
surface of cured tires through the use of
irradiation of the tire surface prior to
molding and curing. The radiation posttreatness process also demonstrated a 2 to
9 percent increase in wet and dry skid
resi stance of ti res.
118
4-76
Table 4-28
RELATIVE ADHESIVE BOND STRENGTHS FOR PLASMA AND
CONVENTIONAL METHODS OF TREATING POLYMER SURFACES (2)
~
Polymer
Treatment Process and Re1 a t i v e Bond S t r e n g t h
Control
Plasma
Abrasion
Corona
Chemical
Polyethylene
1
12.1
--
P o___.
l y p__
r o_
p y..l e n e
1
221
--
Polyester
1
19
-
3
4.5
5.1
81
649
--
1
Plasma polymerized o r g a n i c c o a t i n g s e l i m i n a t e many of t h e problems a s s o c i a t e d w i t h
c o n v e n t i o n a l t h e r m a l l y cured c o a t i n g systems ( s o l v e n t removal
, excess
thermal
e n e r g i e s , e t c . ) and have unique p r o p e r t i e s such as v e r y h i g h chemical and a b r a s i o n
continuous o r p i n - h o l e f r e e f i l m
r e s i s t a n c e ( h i g h degree of c r o s s - l i n k i n g ) ,
structures, multilayer f i l m s with varying indices of r e f r a c t i o n ( a n t i g l a r e
c o a t i n g s ) , t h i n membrane and b a r r i e r f i l m s t r u c t u r e s , d i e l e c t r i c f i l m s ,
c o m p a t i b l e f i l m s f o r biomedical a p p l i c a t i o n s ( F i g u r e 4-33).
and b l o o d
Some r e p r e s e n t a t i v e
o r g a n i c s t a r t i n g m a t e r i a l s and t h e i r r e s u l t a n t plasma polymerized f i l m s t r u c t u r e s
and a p p l i c a t i o n s a r e shown i n Table 4-29.
(46,120-122)
Table 4-29
PLASMA COATINGS
T r e a t e d i n Plasma
(46)
R e s u l t a n t Polymer
References
Tetrafluoroethylene
Thin d i e l e c t r i c f i l m s on metal
s u r f aces f o r c a p a c i t o r
applications
120
Hexamethyldisiloxane,
t e t r a e t h y l t i n and
oxygen
Abrasion r e s i s t a n c e , l o w moist u r e p e r m e a b i l i t y and a n t i reflection properties
121
Benzoni tr i1e
Membrane s t r u c t u r e s on
s i 1i c o n e - p o l y c a r b o n a t e f i l m s
f o r gas s e p a r a t i o n processes
122
4-77
~
-
CONTROLLED
THERMAL
STABILITY
SURFACE TREATMENTS
AND COATINGS FOR
PLASTICS
BARRIER
PROPERTIES
ELASTOMERS
GLASSES
CERAMICS
CONTROLLED LIGHT
TRANSMISSIVITY
ADHESION
PROMOTION
WETTABILITY
COMPATIBILITY
Figure 4-33. Applications of Plasma Processing Technologies
4-78
Section 5
COST AND ENERGY SAVINGS COMPARISONS
I n o r d e r t o p r o j e c t t h e f u t u r e usage o f r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s
i t i s necessary t o compare t h e c o s t and p o t e n t i a l energy savings o f t h i s technology
w i t h t h a t o f c o m p e t i t i v e m a t e r i a l s p r o c e s s i n g a l t e r n a t i v e s f o r a g i v e n s e t o f mark e t o r a p p l i c a t i o n areas.
I n a d d i t i o n , changes i n technology which c o u l d have
an impact must a l s o be examined.
I n t h i s s e c t i o n , a c o s t and energy savings com-
p a r i s o n f o r each of t h e major a p p l i c a t i o n s o f r a d i a t i o n p r o c e s s i n g i s discussed.
Techno1 o g i c a l f a c t o r s a f f e c t i n g market p r o j e c t i o n s a r e discussed i n S e c t i o n 6.
-
COST COMPARISON
RADIATION PROCESSING
VERSUS THERMAL PROCESSING TECHNOLOGIES
When a n a l y z i n g t h e c o s t of c o m p e t i t i v e p r o c e s s i n g ( c u r ng o r c r o s s - l i n k n g ) of
p o l y m e r i c m a t e r i a l s s e v e r a l f a c t o r s must be c o n s i d e r e d
These f a c t o r s n c l u d e t h e
following:
Cost o f equipment
Cost o f f u e l l e l e c t r i c i t y (energy s a v i n g s )
E f f i c i e n c y o f equipment
Scrap l o s s e s i n t h e process
Labor and f l o o r space requirements
P r o d u c t i o n r a t e s and a b i l i t y t o e l i m i n a t e h a n d l i n g o p e r a t i o n s ;
c a p a b i l i t y f o r complete automation
Cost of p o l y m e r i c m a t e r i a l s ( c o a t i n g s ) undergoing t h e processi n g operation
Environmental f a c t o r s ( r a d i a t i o n s h i e l d i n g , p o l 1 u t i o n 1.
A l l o f t h e f a c t o r s a s s o c i a t e d w i t h c o s t comparisons between c o n v e n t i o n a l g a s - f i r e d
ovens and v a r i o u s t y p e s o f r a d i a t i o n p r o c e s s i n g equipment are b e s t d e s c r i b e d by t h e
f o l l o w i n g examples f o r each o f t h e major market areas d e s c r i b e d i n t h i s
report.
(123)
5-1
Coatings
The use o f r a d i a t i o n c u r a b l e c o a t i n g s i s a s i g n i f i c a n t a l t e r n a t i v e f o r t h e reduct i o n o f energy consumption and compliance w i t h a i r p o l l u t i o n l e g i s l a t i o n f o r t h i s
industry.
The c o s t comparison and energy e f f i c i e n c y d a t a f o r p r o c e s s i n g o f a wood
f i l l e r v e h i c l e u s i n g UV and i n f r a r e d p r o c e s s i n g equipment i s g i v e n i n Table 5-1.
The UV processor and a s s o c i a t e d c o a t i n g system r e s u l t i n lower p r o d u c t p r o d u c t i o n
c o s t s w i t h a s u b s t a n t i a l savings i n energy over t h e thermal c u r i n g c o a t i n g operation.
The o v e r a l l power consumption c o s t s p e r square f o o t o f p r o d u c t a r e a p p r o x i -
m a t e l y 0.1
f o r t h e UV system, and 0.2
f o r t h e I R system. (123,124)
One o f t h e major commercial successes i n r a d i a t i o n p r o c e s s i n g over t h e thermal
p r o c e s s i n g techniques f o r c o a t i n g s and i n k s has been demonstrated by t h e can i n d u s try.
I n t h e U.S.,
Adolph Coors Company and American Can Company have been t h e
l e a d e r s i n u t i l i z a t i o n o f UV c u r a b l e i n k s and o v e r p r i n t v a r n i s h e s f o r beer and
beverage can p r o d u c t s .
Coors has r e p o r t e d t h a t 246% more energy i s r e q u i r e d t o
t h e r m a l l y c u r e c o n v e n t i o n a l s o l v e n t o r water-based i n k s or c o a t i n g s t h a n t o c u r e
A t y p i c a l can l i n e ( F i g u r e 4-5) o p e r a t i n g
u l t r a v i o l e t s e n s i t i v e i n k s and c o a t i n g s .
a t 600 t o 2000 cans/min on a 7 hr/day, 250-day work y e a r u s i n g a UV d r y e r would save
over 1 b i l l i o n B t u a year w i t h an approximate p r o d u c t i o n r a t e o f over 63 m i l l i o n
beer cans a n n u a l l y .
An e s t i m a t e o f energy savings and comparison o f UV versus
thermal d r y i n g o f i n k s and c o a t i n g s based on Coors experience i s g i v e n i n Table
5-2.
American Can Company has had s i m i l a r energy savings experience ( o v e r 100
b i l l i o n B t u saved i n g o i n g f r o m n a t u r a l g a s - f i r e d ovens t o UV r a d i a t i o n p r o c e s s i n g
equipment) w i t h UV c u r a b l e i n k s and c o a t i n g s i n a system c o m p l e t e l y d i f f e r e n t i n
c h e m i s t r y t h a n t h a t o f t h e Coors c o a t i n g .
The Coors c o a t i n g system i s c u r e d
t h r o u g h a f r e e r a d i c a l mechanism; t h e American Can c o a t i n g system i s c u r e d through
a photoinduced c a t i o n i c r i n g opening epoxy r e s i n r e a c t i o n mechanism. (53,54,124)
Table 5-3 summarizes d a t a f r o m a h y p o t h e t i c a l c o s t model a s s o c i a t e d w i t h t h e use o f
a thermal oven, an e l e c t r o n c u r t a i n processor, and a UV c u r i n g chamber. (125)
-
Each
system i s designed t o process 180 m i l l i o n square f e e t o f aluminum c o i l s t o c k per
y e a r (1 m i l t h i c k c o a t i n g ) a t l i n e speeds of up t o 150 f e e t per m i n u t e .
In this
model t h e h o u r l y p r o c e s s i n g c o s t s and c o s t per square f o o t o f p r o d u c t produced f o r
t h e c o n v e n t i o n a l thermal c o a t i n g / c u r i n g o p e r a t i o n a r e a p p r o x i m a t e l y t w i c e those o f
e i t h e r r a d i a t i o n process.
Coating m a t e r i a l c o s t s a s s o c i a t e d w i t h t h i s model a r e
a p p r o x i m a t e l y 1.18 cents/square f o o t f o r a c o n v e n t i o n a l so vent-based (35% s o l i d s )
alkyd varnish.
T h i s i s a p p r o x i m a t e l y e q u i v a l e n t t o a 100% s o l i d s EB/UV v a r n i s h
c o s t i n g 1.17 c e n t s t o 1.19 cents/square f o o t .
5-2
A more d e t a l e d and complete analy-
Table 5-1
UV
AND IR PROCESSING COST AND ENERGY EFFICIENCY DATA
(123)
Typical UV
Typical I R
Oven length (ft)
10-30
90
Line speed (fpm)
60-150
60
Po 1yester
Urea-A1 kyd
90-100
35-65
2
2
700-800
500
Coats
1
2
Cure time (sec)
10
90
Exit temp
100
130
No
Yes
Wood filler vehicle
Nonvolatile (%)
Film thickness (mils)
Coverage (wet) (sq ft/gal)
(OF)
coo1
Cost of filler ($/gal)
5.00-6.00
Cost per sq ft (6)
Per coat
Total
0.7-0.9
0.7-0.9
Power (kw)
2 00-3 00
0.9-1.3
1.8-2.6
100
250
Power per sq ft ($)
Less than 0.1
App. 0.2 (two coats)
Surface appearance
Ex (one coat)
G (two coats)
Hardness
Ex
G
Sand i ng
Ex
VG
Ex
=
excellent, G
=
good, VG
=
very good
5-3
Table 5-2
COMPARISON OF UV VERSUS GAS FIRED THERMAL CURE
COATING/INK SYSTEMS FOR BEVERAGE CONTAINERS (53)
Gas fired ovens cost 2.5 times
more than a UV processor
pment Costs
Gas Costs ($0.43/1000 ft3)
- The aas
Electrical Costs ($O.Ol/KWH)
-
f red w e n requires
4,OOi,OOO BTU/hr while the UV
processor uses no gas
UV requires 22 KWH, the gas fired
oven require 15 KWH
Energy and Maintenance Costs - Gas fired ovens have 2-3 times
the energy and maintenance cost
of a UV processor
Ink Costs
-
UV inks are between 1.1 and 1.75
times more expensive than conventional thermal curing ink
systems
Sol vent Emissions
UV has no solvent emissions while
the thermal cure inks release at
least 20% of their weight
F1 oor Space Requirements
Gas fired ovens require 10 times
the space as the UV processor
5-4
Table 5-3
OPERATING COST ANALYSIS FOR RADIATION VERSUS THERMAL PROCESSING
EQUIPMENT FOR COATING ALUMINUM COIL STOCK (125)
Thermal
Oven,
Electron
Curtain,
A
210,000
8 Lamp UV
Processing
300 watts/inch,
80,000.
Purchase P r i c e
Pol 1u t i on Control
Equipment
Maintenance
Gas
Electricity
Labor
F1oor Space
Total
200,000
7,500
2 ,000
23, OOOa
8,700b
108,0OOc
3,000
172,000
8, OOOd
3,000
72,000
3 50
105,350
9,600
72.000
300
91,900
Hourly Processing Costs
(4000 hours/year)
43.05
26.34
22.98
Processing Costs
cents/square f o o t
Processing Parameters:
-1,000
0.073
0.120
-2, oooe
--
0.064
180 m i l l i o n square feet/year a t 150 feet/minute w i t h a
c o a t i n g thickness o f 1 m i l .
“14.4 MSCF a t $l.GO/MSCF.
b290 MKWH a t $0.03/KWH.
c1.5 people a t $18/hour.
d I n e r t i n g gas generator.
e I n c l udes one complete change o f 1amps a f t e r 2000 hours.
5- 5
s i s f o r coil coating systems i s contained in reference 126 and a summary of these
r e s u l t s i s shown in Tables 5-4 and 5-5.
-
The curing of c l e a r and pigmented coatings on p l a s t i c s u b s t r a t e s i s an area where
radiation processing techniques have a d i s t i n c t advantage over conventional thermal
curing methods. Table 5-6 describes t h r e e curing methods ( E B , U V , and gas-fired
ovens) f o r processing coatings on p l a s t i c s u b s t r a t e s . The p a r t i c u l a r advantage of
radiation (E6 or U V ) curing over the thermal curing process is the very short exposure times f o r the radiatiom systems over those of the conventional ttiermal c u r ing process. The high heat-long exposure times experienced by the p l a s t i c subs t r a t e during the coating/curing process can lead t o h i g h scrap l o s s e s , and i n f e r -
ior q u a l i t y in the finished product.
(123)
These examples o f comparative processing methodologies for the coatings industry
a l l tend t o show t h a t a substantial cost and energy s a v i n g s can be realized w i t h
U V / E B and even IR radiation processing equipment over t h a t of conventional gas-f i r e d ovens.
Printing I n k s
The advantages f o r using u l t r a v i o l e t radiation processing equipment r a t h e r than a
conventional e l e c t r i c dryer system f o r the printing ink industry can be outlined as
follows:
0
UV-radiation processing equipment has a lower purchase price and can
o f f e r short-term payback on i t s investment.
0
I n s t a l l a t i o n costs are usually lower and the required f l o o r space f o r UV
equipment i s much smaller than conventional e l e c t r i c dryer ovens.
0
Energy consumption is lower, r e s u l t i n g in a reduced unit-product c o s t .
0
UV inks have high f l a s h points and are 100% reactive s o l i d s ; t h u s , t h e r e
are no f i r e hazards, no emissions, no odors. Insurance costs are reduced
and pollution control devices are not required.
0
Two UV curable ink l i n e s will service 70 t o 80% o f the stock in a general
screen-printing s h o p , and when the inks are cured they will n o t smear or
bleed i n t o the product p i l e . T h i s eliminates special racking or handling
procedures and stock wastage i s reduced.
0
UV inks are s t a b l e on the press and allow f o r easy clean-up a f t e r the run
i s finished.
0
UV inks allow f o r rapid product processing and f a s t delivery of product.
5 -6
~
Table 5-4
COMPARISON OF ENERGY REQUIREMENTS FOR DIFFERENT
ENERGY SOURCES ON A MODEL COIL COATING LINE (1261
cn
I
v
MMBtu Rlequired per
Hour (Energy Consumption)
Sol vent
Other
Air
Evaporation
Peak Oven
Temperature
Peak Metal
Temperature
Metal
55% s o l i d s
( s o l vent based
660 F
450 F
0.699
Ignored
I R Heaters
55% s o l i d s
( s o l vent based 1
300 F
450 F
0.699
0.1
I R Heaters
55% s o l i d s
(water based
--
300 F
0.426
0.282
--
--
450 F
----- Not
100% s o l i d s
None
None
Energy Source
Coating
Conventional f o s s i l
f u e l (A.D. L i t t l e
Model System 1
I n d u c t i o n Heating
E l e c t r o n Beam or
Electrocurtai n
None
Broken Dow
None
Total
0.880
5.261
--
3.66
4.46
--
3.23
3.94
3.682
by Source---None
--
3.4
0.25
Table 5-5
COMPARATIVE COST ANALYSIS FOR H I G H ENERGY ELECTRON CURED
COATING SYSTEMS VERSUS CONVENTIONAL THERMALLY CURED
COATING SYSTEMS ON ALUMINUM COIL STOCK (126)
Curing Method
Coating System
Afterburner
Therm a1
Hydrocarbon sol vent
(45% s o l i d s 1
No preheat
preheat
Thermal
Tot81 Energya T o t a l Gas
10 BTU/hr
1000 c f h
Cost
$/hr
_(__
15.7
10.7
15.4
10.4
40.03
26.78
Water base
(45% s o l i d s )
7.3
7
18.47
Thermal
80% water I 2 0%
alcohol (45%
solids)
7.8
7.5
19.71
High Energy
Electron
100% s o l i d s
0.85
0.4
2.27
aUsing 1 k W h r = 10,500 BTU f o r e l e c t r i c a l power:
5-8
thermal energy conversion.
Table 5-6
COMPARISON OF CURING METHODS (1
23)
EB
Ultraviolet
300 to 500K (H)
20 to l O O K (L)
10-30
10-30
90-300
On-of f operation
Yes
Yes
No
Inert atmosphere
Yes
No
No
Ambient
100-200
130+
1 sec or less
Seconds
Minutes
Cure coatings on plastics
Yes
Yes
NO
Cure pigmented coatings
Yes
Sometimes
Yes
Require catalyst
No
Yes
Somet i mes
90- 100
90-100
35-65
700-1400
700-1400
400-500
8 to 20 (H)
8 to 20 (H)
L-M
L
M
X-Rays
uv
Heat
Capital cost ($)
Length (ft)
Cure temp.
(OF)
Cure time
Coating solids (%)
Coating coverage, sq ft/mil
Coating cost ($/gal )
Cost per mil sq ft
Hazard
K
= 1,000
Note:
low(L), medium(M), high(H)
5-9
Oven
100 to 200K
4 to 10
(M)
(L)
The model used f o r economic j u s t i f i c a t i o n o f p u r c h a s i n g UV r a d i a t i o n p r o c e s s i n g
equipment over a c o n v e n t i o n a l e l e c t r i c d r y e r system i s shown i n T a b l e 5-7.
The
model was based on a p r i n t i n g o p e r a t i o n capable o f r u n n i n g 2400 i m p r e s s i o n s per
hour i n 250 days per year ( s i n g l e s h i f t ) and p r o d u c i n g 29,880,000
product.
square f e e t o f
-
The c o s t savings i n f a v o r o f t h e UV p r o c e s s i n g equipment was a p p r o x i ~
Thus t h e b e n e f i t s t o be d e r i v e d f r o m a d o p t i n g a UV c u r i n g system,
m a t e l y $237,055.
compared t o a c o n v e n t i o n a l d r y i n g system, are s u b s t a n t i a l and i n c r e a s e as f u e l
c o s t s escal a t e .
The unique method o f p r i n t i n g rounded p l a s t i c c o n t a i n e r s ( F i g u r e 4-18) o f f e r s
an o p p o r t u n i t y t o make a d i r e c t comparison between two types ( l i n e a r and compact on
mandrel UV lamp c o n f i g u r a t i o n ) o f UV r a d i a t i o n p r o c e s s i n g equipment.
The compari-
son o f annual o p e r a t i n g and p r o d u c t p r o d u c t i o n c o s t s f o r each system i s g i v e n i n
Tables 5-8 and 5-9.
i s 124,494,196
The n e t p r o d u c t p r o d u c t i o n r a t e f o r t h e compact UV lamp design
cups per year ( C P Y ) compared w i t h 93,363,000
lamp p r o c e s s i n g u n i t .
CPY f o r t h e l i n e a r UV
The annual c o s t savings f o r t h e manufacturer u s i n g t h e com-
p a c t UV d r y e r system i s $193,068.
There i s a l s o a s u b s t a n t i a l s a v i n g s on produc-
t i o n losses due t o f i r e s ( s t o p p i n g o f t h e l i n e , c a u s i n g cups t o remain s t a t i o n a r y
under t h e h o t UV lamps) by u s i n g t h e compact UV lamp system r a t h e r t h a n t h e l i n e a r
UV d r y e r . (81)
Adhes ives
A c o s t comparison f o r thermal and e l e c t r o n beam c u r i n g o f adhesive systems i s g i v e n
i n Table 5-10.
I n t h e study, a 60-inch thermal oven ( 6 MBtu/hour), c o s t i n g
2
$160,000, p r o d u c i n g 2,569 y d / h r o f adhesive coated p r o d u c t i s compared w i t h an
2
e l e c t r o n beam p r o c e s s i n g u n i t , c o s t i n g $200,000, and p r o d u c i n g 3,400 y d / h r coated
p r o d u c t . (127) S i m i l a r r e s u l t s a r e observed as those shown i n t h e c o a t i n g s i n d u s t r y
i n t h a t b o t h e l e c t r o n beam and UV p r o c e s s i n g u n i t s , f o r p r e s s u r e s e n s i t i v e adhesive
t a p e and l a b e l s , can reduce o p e r a t i n g and p r o d u c t manufacturing c o s t s by as much as
50% ( T a b l e 5-11).
(127)
E 1ec t ron ic s /C ommun ic a t ion
Cost, energy savings, and p r o d u c t i o n r a t e comparisons f o r p r o d u c t s i n t h e e l e c t r o n i c s and communications i n d u s t r y processed by thermal o r r a d i a t i o n methods were
not available a t the time of w r i t i n g t h i s report.
I t s h o u l d be noted, however,
t h a t many o f t h e p r o d u c t s a s s o c i a t e d w i t h these i n d u s t r i e s can be manufactured
u t i l i z i n g a wide range o f r a d i a t i o n energies, as was p r e v i o u s l y d e s c r i b e d f o r i n t e g r a t e d c i r c u i t s , p r i n t e d c i r c u i t boards, and e l e c t r o m a g n e t i c r e c o r d i n g media a p p l i -
5-1 0
-
Table 5-7
COMPARISON OF DRYER PROCESSING COSTS FOR PRINTING APPLICATIONS (68)
Electric
Drver
UV Processing
Eauipment
Purchase Price
$38,000
$18,800
Width (inches)
38
38
2,800
3,600
225
50
4,000
1,500
30
15.2
Drver Costs
Processing Capacity
(Impressions per Hour)
Floor Space (Square Feet)
Weight (Pounds)
Power Consumption
(Ki 1 owat/Hours)
Power Supply (Volts A.C.,
Amps, Herz)
2 40/ 1 20/60
Ink Cost (Per Gallon)
240/6 O/ 60
$24
$65
$0.015
$0.017
$24,504
$20,354
$5,520,861
$5,293,028
$3,712
$1,640
$5,552,077
$5,315,022
Ink Cost (Per Square Feet)
Product Production Costs
Labor Cost
Materials and Floor Space Cost
Energy Cost
TOTAL OPERATING COSTS
5-1 1
Table 5-a
COMPARISON OF ANNUAL OPERATING COST, PRODUCTION AND
COST SAVINGS BETWEEN A CONVENTIONAL UV LINEAR RADIATION
PROCESSOR AND A COMPACT ON-MANDREL UV PROCESSOR (81)
Conventional UV
Capital (printer/dryer),
8% o f $115,000
Operator, $5 per hr.
$
Floorspace, $3/sq. ft./yr.
192
522
Dryer E l e c t r i c a l , 3f#/KWH
1,188
3,240
Dryer Maintenance, $8/hr.
64
160
Dryer p a r t s
2,400
$
Scheduled Hours
600
$
51,522
Hours l o s t t o f i r e s , jams 81
maintenance o f d r y e r
Net Production Hours
720
720
50
8
6,472
6,430
P r i n t e r Speed
Loss Rate
a t Transfers
Net Production Rate
47,244
7,200
7,200
Hours l o s t t o causes
o t h e r than d r y e r f a i l u r e
9,200
36,000
36,000
*
TOTAL COST
On-Mandrel UV
$
9,200
-
250 CPM
15,000 CPH
325 CPM
19,500 CPH
3.2%
480 CPH
195 CPH
14,520 CPH
19,305 CPH
1%
CPM = Cups per min
CPH = Cups p e r hour
Annual Production
93,363,000
CPY
124,494,196
CPY = cups p e r year
Sales Value o f
Production a t
$14/M cups
$ 1,307,090
5-1 2
$ 1,742,918
CPY
Table 5-9
COST SAVINGS COMPARISONS BETWEEN CONVENTIONAL UV AND
ON-MANDREL UV PROCESSORS FOR A PLANT RATED AT
1.12 BILLION PRINTED CUP CAPACITY (81)
Conventional UV
On-Mandrel UV
12
Printers Required
9
Annual Operating Costs
per Printer
$
51,522
$
47,244
Annual Operating Cost
0
618,264
$
425,196
$
193,068
Anuual Saving using
On-Mandrel Drying
5-1 3
Table 5-10
PRELIMINARY COST COMPARISON FOR THERMAL
AND ELECTRON BEAM CURING OF ADHESIVES (127)
I.
-
Thermal (60" oven capable of 100 ft/minute)
__
Assume a consumption of 6 MBTU/hour in an oven costing $160,000.
Area of the oven -120' x 12', -1500 ft2.
Utilization o f 85% with 8% downtime for maintenance (2,567 -yd2/hr),
Amortize capital c sts over 5 years
Space use at $l/ft B
Fuel costs at 6 MBTU/hra
Maintenance parts
Services (cooling water, 20 kW
auxi 1 i ary power, air, Etc .)
Operator labor (100% OH)
Total operating costs
11.
$32,000.OO/yr
1,500.OO/yr
$13.50/hr
.30/hr
2.OO/hr
10.00/hr
$25.80/ hr
Electron Beam (60" curing head capable of 120'/minute)
Assume a consumption of 20 kilowatts in a $tation costing $200,000.
Area of curing station -12' x 16', -200 ft .
Utilization of 90% with under 5% downtime for maintenance (3,400 yd2/hr).
Amortize capital c sts over 5 years
Space use at $l/ft B
Maintenance contract for system
Power costs at 3 /kWhr
Inert gas costs
Services (water, air, etc.)
Operator 1 abor (100% OH)C
Total operating costs
$40,000.OO/yr
200.OO/yr
5,000.OO/yr
.60/hr
2.OO/hr
.20/hr
5.OO/hr
$ 7.80/hr
$
The following gross hourly and square yard operating costsd result based upon these
numbers:
Thermal Oven
Electron Processor
aBased upon
bBased upon
CBased upon
dBased upon
to that of
2000 hr
$fy&
4000 hr
$/vdz
6000 hr
$fy&
$41.35
0.016
0.009
$32.95
19.10
0.013
0.006
$30.15
15.35
0.012
0.004
30.40
gas costs of $2.25/1000 cu. ft. for gas at 1000 BTU/cu. ft.
a full man for operation and maintenance.
0 . 5 man for operation.
the use of water based adhesive whose dry mil cost is equivalent
the electron curable system.
5-1 4
Table 5-11
ECONOMICS, PHOTOCHEMICAL vs. THERMAL PRODUCTION LINES
PRESSURE-SENSITIVE ADHESIVE TAPE AND LABELS (127)
E le c t ro n Beam
Line speed
(f t / m i n)
Powep consumption
(W
UV Cure
300
40.2
(Solvent-Based Adhesi v e l
300
300
510
5,100
Operating costs
($1
Power
Maintenance
Nitrogen gas
Water
Total Costs
C apital Costs
.81
3.50
2.75
.20
10.20
4.50
7.26
14.70
$200,000
NA
NA
$13,000
NA = not applic a b le
5-1 5
18.00
2.70
NA
NA
20.70
$130,000
cations.
The c o m p l e x i t y and h i g h performance q u a l i t y o f these p r o d u c t s demands
t h a t t h e p r o c e s s i n g o p e r a t i o n s be c o s t - e f f e c t i v e under h i g h p r o d u c t i o n r a t e c o n d i t i o n s ; t h e s e c o n s t r a i n t s can o n l y be achieved t h r o u g h r a d i a t i o n p r o c e s s i n g
techniques.
(128)
P l a s t i c and Rubber M a t e r i a l s
Several f a c t o r s i n d i c a t e t h a t e l e c t r o n beam (EB) systems a r e more c o s t - e f f e c t i v e
t h a n thermo-chemical systems f o r p r o c e s s i n g p l a s t i c and r u b b e r m a t e r i a l s .
0
R a d i a t i o n p r o c e s s i n g can save b o t h energy and p r o d u c t i o n c o s t .
The e l e c t r i c a l energy used t o generate e l e c t r o n beams i s more
expensive t h a n f o s s i l - f u e l energy c o s t s a s s o c i a t e d w i t h steam
o r gas f i r e d ovens, b u t t h e lower energy i n p u t per u n i t o f
m a t e r i a l processed b y EB techniques more t h a n o f f s e t s t h i s
higher operational cost.
0
R a d i a t i o n p r o c e s s i n g equipment saves f l o o r space compared t o
h e a t c u r i n g systems r e q u i r i n g l o n g steam tubes o r expansive h o t
a i r ovens. T y p i c a l r a d i a t i o n p r o c e s s i n g equipment r e q u i r e s
l e s s than 1,000 square f e e t o f f l o o r space.
0
There i s l e s s p r o d u c t scrap l o s s w i t h r a d i a t i o n p r o c e s s i n g
t e c h n i q u e s due t o e f f i c i e n t t h r o u g h cure. Thermal c u r e p r o cesses can r e s u l t i n o v e r c u r e and nonuniform c u r e o f a p r o d u c t .
0
Thermo-chemical c u r i n g systems r e q u i r e t h e use o f p e r o x i d e and
other c a t a l y s t s not r e q u i r e d i n r a d i a t i o n (high-energy) processing technologies. E l i m i n a t i o n of these thermal cure catal y s t s reduces t h e l e v e l o f a n t i o x i d a n t s and a n t i o z o n a n t s b y
as much as 50%, thus e f f e c t i n g a c o n s i d e r a b l e m a t e r i a l s a v i n g s
f o r t h e r a d i a t i o n cured product.
0
The c o s t o f e l e c t r o n beam r a d i a t i o n i n t h e p a s t t h r e e decades
has been reduced f r o m $4.00 t o produce 1 KWH o f r a d i a t i o n t o
a p p r o x i m a t e l y $0.03 t o $0.25 p e r KWH, depending on t h e e q u i p ment c o n f i g u r a t i o n r e q u i r e m e n t s . T h i s r e d u c t i o n has come about
p r i m a r i l y due t o t h e h i g h e r e f f i c i e n c y o f s u c c e s s i v e generat i o n s o f high-energy e l e c t r o n beam a c c e l e r a t o r equipment.
Comparative examples f o r c o n t i n u o u s t h e r m a l v u l c a n i z a t i o n ( C V ) and h i g h - e n e r g y
e l e c t r o n beam (EB) c u r i n g ( c r o s s - l i n k i n g ) of p o l y e t h y l e n e w i r e i n s u l a t i o n i s shown
i n Tables 5-12 and 5-13.
As can be seen i n Table 5-12 t h e a c t u a l t o t a l energy
c o s t s [energy c o s t l y e a r (4,000 h o u r s ) ] f o r EB a r e h i g h e r t h a n t h e CV process b u t
t h e energy c o s t per pound of p r o d u c t manufactured i s $0.013 f o r CV and o n l y $0.006
f o r EB.
S i m i l a r r e s u l t s a r e d e s c r i b e d i n Table 5-13 i n which t h e CV process
c o s t / l b o f i n s u l a t i o n (2,659,500
(8,697,000
l b l y e a r ) i s $0.086;
l b / y e a r ) f o r t h e EB process i s o n l y $0.046.
5-16
the cost/lb of insulation
(129,130)
Table 5-12
ENERGY COMPARISON, CV AND EB, FOR WIRE
INSULATION CROSS-LINKING
(129)
cv a
Systems P r o p e r t i e s
E B ~
38
Linespeed, fpm
Ins. lb/hr
207.5
233
1260
-
BTU /1 b
Energy c o s t / l b
Energy c o s t l y r (4000 h r )
1b l y r
1000's
1127
$0.013
$0.006
$10,560
$29 500
a30
Gauge, AWG (250 MCM)
Conductor , m i 1s ( 575 1
I n s u l a t i o n , m i l s (92)
OD over ins.,
5783
m i l s (759)
I n s . sp. g r a v i t y (1.0)
I n s . w t . l b 1 0 0 0 / f t (91)
EB kV (1564)
aAssume 750 e t c .
bia4 kw e t c .
5-1 7
5,040
Table 5-13
COST COMPARISON DATA (CV/EB) (129)
-
CV System
Electron Beam System
Caei tal Costs
6" extruder 1 i ne and
CV, installed, complete
with steam generator
CaDi tal Costs
6" extruder 1 i ne
w.0.
CV, installed complete
1500 kv 50 mA
Dynamitron, complete
with accessories
480,000
Wire Line, complete
90,000
Instal 1 ation, shielding
etc.
Total :
OPeratinq Costs, Annual
Equipment (assuming 10
yr amortization
Labor (1 man/shift)
Steam
Power
Water
Maintenance
Taxes, insurance, etc.
Total :
Cost/l b o f i nsul ati on
2,659,500 lb/yr
$300.000
$750,000
125,000
$995,000
Oeeratinq Costs, Annual
Equipment (assuming 10
yr amortization)
Labor (2 men/shi ft)
Steam
Power (2 extruders and
accelerator)
Water
Maintenance
Taxes, insurance, etc.
$ 75,000
72 ,000
17,000
45 ,000
2,000
16,000
1,500
Total :
$228.500
Cost/l b o f insul at i on
$0.086
8,697,000 1 b/yr
5-18
$ 99,500
144,000
-131,100
8,000
14,400
2 ,000
$399,000
$0.046
Other economic s t u d i e s on EB p r o c e s s i n g of p o l y e t h y l e n e p i p e , calendered r u b b e r
sheet, and p o l y e t h y l e n e f i l m can be found i n Reference 131.
PLASMA PROCESSING
Plasma c o a t i n g and polymer s u r f a c e t r e a t m e n t equipment and processes a r e we1 1 -e s t a b l i s h e d f o r t r e a t i n g batches o f small o b j e c t s and, i n some cases, continuous
p r o c e s s i n g has had commercial success i n t h e t e x t i l e and paper c o a t i n g i n d u s t r i e s .
An e s t i m a t e d c o s t t o plasma t r e a t small o b j e c t s ( b a t c h p r o c e s s ) and a continuous
web o r f i l m ( p o l y v i n y l 3 i l W d e ) i s g i v e n i n Tables 5-14 and 5-15.
(126-,132)
-These
t r e a t m e n t processes are unique t o plasma p r o c e s s i n g t e c h n o l o g i e s ; t h u s comparisons
w i t h o t h e r t r e a t m e n t processes are n o t p o s s i b l e .
IMPACT OF FUEL PRICES
Because energy c o s t s a r e a l a r g e f a c t o r i n thermal p r o c e s s i n g o f p o l y m e r i c mater i a l s , i t would n o r m a l l y be expected t h a t f u e l p r i c e s s h o u l d have a l a r g e e f f e c t
on t h e f u t u r e c o m p e t i t i v e n e s s o f r a d i a t i o n processing t e c h n o l o g i e s .
The p r o j e c t i o n
o f f u t u r e energy p r i c e s i s approximate a t b e s t , b u t t h e gross t r e n d i s f o r t h e c o s t
of e l e c t r i c i t y t o i n c r e a s e a t a r a t e much l e s s than t h a t f o r n a t u r a l gas o r o i l .
The p r e s e n t Department o f Energy p r o j e c t i o n s show t h a t t h e c o s t o f e l e c t r i c i t y w i l l
i n c r e a s e r a t h e r s l o w l y through 1995, whereas t h e c o s t o f n a t u r a l gas i s expected t o
double d u r i n g t h i s t i m e p e r i o d . (133)
Therefore, by 1995, r a d i a t i o n p r o c e s s i n g o f
p o l y m e r i c m a t e r i a l s (energy e f f i c i e n c i e s o f a p p r o x i m a t e l y 90 p e r c e n t ) w i l l remain
a t t r a c t i v e f r o m an o v e r a l l energy c o s t v i e w p o i n t .
Energy savings alone, however,
has n o t been a major f a c t o r i n c o n v i n c i n g some i n d u s t r i e s t o s w i t c h from thermal
c u r i n g (energy i n t e n s i v e ) t o r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s f o r manufacture o f
t h e i r product materials.
O f course l a c k o f f u l l f u e l a v a i l a b i l i t y , such as was
experienced i n t h e 1 9 7 0 ' ~f o~r c e d many i n d u s t r i e s , e s p e c i a l l y t h e p r i n t i n g indust r y , t o q u i c k l y e v a l u a t e r a d i a t i o n p r o c e s s i n g techniques.
They soon d i s c o v e r e d
many a d d i t i o n a l b e n e f i t s ( p r o d u c t i o n speed, p r o d u c t q u a l i t y , v a l u e added p r o d u c t s ,
e t c ) besides energy savings; t h e s e a d d i t i o n a l f a c t o r s became t h e d r i v i n g f o r c e f o r
i n c r e a s i n g t h e growth r a t e o f r a d i a t i o n p r o c e s s i n g of p o l y m e r i c m a t e r i a l s f o r a
wide v a r i e t y o f o t h e r i n d u s t r i a l a p p l i c a t i o n s . (126)
-
5-1 9
Table 5-14
ESTIMATED COST TO PLASMA TREAT SMALL OBJECTS (132)
Bases and Assumptions:
Annual capacity: 40 million p a r t s per year
Operation schedule: 16 hours/day, 250 days/year
January 1984 dol 1ars
C
-aDi
t a l Investment:
Dol 1a r s
Branson model 7150-12436
Pump
Rotator f o r basket
Spare baskets and handling equipment
I n s t a l l a t i o n of e l e c t r i c a l equipment
Spare p a r t s
Total
65,000
15,000
10,000
10,000
5,000
3.000
108,000
ODeratincl Costs
Cost El emen t
Raw materi a1 s
Electricity
Labor and supervision:
Direct 1abor :
Operat or/f oreman
Assistant operator
Supervi s i on
Maintenance:
Labor
Materi a1 s
Payroll burden
Overhead
Factory suppl ies
Quali t y control
1aboratory
Insurance and property t a x
Contingency
Annual ized c a p i t a l
recovery (10 years)
Operating
Requi rement s
luni t s )
Annual
cost,
[dol 1a r s )
Cost Per
Thousand
Parts
Jdoll a r s )
41,840 kwh
0
2,929
0
0.073
2.00 men
2.00 men
0.15 d i r e c t labor
50,000
40,000
13,500
1.250
1.000
0.338
cap invest
cap invest
1abor/super
1abor/super
d i r e c t 1abor
2,160
2,160
26,415
52,830
5,400
0.054
0.054
0.660
1.321
0.135
0.10 d i r e c t labor
0.02 cap invest
0.04 d i r e c t c o s t s
9,000
2,160
8,262
0.225
0.054
0.207
25,823
0.646
240,639
6.016
0.02
0.02
0.25
0.50
0.06
0.24 cap invest
Total
Note:
a 1500 watt, 13.56 megahertz generator consumes 3 KW. A 194 cubic foot/min.
pump i s driven by a motor of 10 horsepower (7.46 kilowatts). Total KW used
= 4000 hrs/year x 10.46 KW = 41,840 KWH/year.
5- 20
Table 5-15
ESTIMATED COST TO PLASMA TREAT A CONTINUOUS
WEB OF PVC FILM (26)
CaPi tal Investment:
Dol 1 ars
Shinetsu apparatus (instal led)
Installation o f electrical equipment
Total
1,000,000
40,000
1,040,000
ODeratinq Costs:
Cost Element
Raw materials
Electricity
Labor and supervision:
Direct 1 abor:
Operat or/f oreman
Assistant operator
Supervision
Maintenance:
Labor
Materials
Payroll burden
Overhead
Factory supplies
Qual i ty control
1 aboratory
Insurance and property tax
Contingency
Annualized capital recovery
Annual Costs
Operating
Annual
Requirements
Cost,
(units)
(dollars)
1,280,000 kwh
0
89,600
0
0.311
2 men
2 men
0.15 direct labor
50,000
40,000
13,500
0.174
0.139
0.047
0.02 cap invest
0.02 cap invest
0.25 1 abor/super
0.50 1 abor/super
0.06 direct labor
20,800
20,800
31,075
62,150
5,400
0.072
0.072
0.108
0.216
0.019
0.10 direct 1 abor
0.02 cap invest
0.04 direct costs
0.24 cap invest
9 ,000
20,800
14,525
248.664
0.031
0.072
0.050
0.863
626,314
2.175
Total
Note:
Cost Per
Thousand
Sq. Ft.
(dol 1 ars)
Total power demand = 320 KW for pumps, generator and ancillaries
16 hrs/day x 250 days/year = 1.28 million KWH.
5-21
Section 6
SALES HISTORY/MARKET PROJECTIONS
The o v e r a l l growth o f r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s (UV and E6 r a d i a t i o n p r o c e s s i n g a p p l i c a t i o n s ) f o r t h e f u t u r e depends on t h e growth ( h i s t o r i c and
f u t u r e ) o f c e r t a i n i n d i v i d u a l i n d u s t r i e s and s p e c i f i c market segments w i t h i n t h e s e
i n d u s t r i e s which can use o r c o n v e r t t o r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s ( T a b l e
6-1).
(134)
section.
S p e c i f i c segments o f t h e c o a t i n g s i n d u s t r y s e r v e as examples i n t h i s
Market p r o j e c t i o n s f o r r a d i a t i o n p r o c e s s i n g equipment a r e provided, and
c o m p e t i t i v e f a c t o r s f r o m t h e e x i s t i n g and emerging t e c h n o l o g i e s a r e summarized.
COATINGS
The c o a t i n g s i n d u s t r y has an o v e r a l l h i s t o r i c growth r a t e between 8 t o 10% p e r year
(1977 t o 1982) f o r t h r e e combined major p r o d u c t types:
trade sales or architec-
t u r a l c o a t i n g s , i n d u s t r i a l p r o d u c t f i n i s h e s , and s p e c i a l purpose c o a t i n g s ( F i g u r e
6-1).
The most i m p o r t a n t area f o r p e n e t r a t i o n by r a d i a t i o n p r o c e s s i n g techniques
i s t h e i n d u s t r i a l p r o d u c t f i n i s h i n g (IPF) l i n e segment o f t h e c o a t i n g s i r l d u s t r y .
Table 6-2 l i s t s t h e t o t a l i n d u s t r i a l p r o d u c t f i n i s h i n g shipment values f o r 1977
through 1985 w i t h t h e p r o j e c t e d gross n a t i o n a l p r o d u c t (GNP) values f o r each
year. (135-139)
The growth r a t e s f o r GNP a r e w e l l e s t a b l i s h e d (10 p e r c e n t
a n n u a l l y ) and can be e a s i l y p r o j e c t e d i n t o t h e year 1990.
(135) The
o f IPF t o GNP f o r t h e s e n i n e years i s a p p r o x i m a t e l y 0.92;
thus, a p r o j e c t e d IPF
average r a t i o
d o l l a r v a l u e volume f o r 1990 i s c a l c u l a t e d t o be about 6 b i l l i o n d o l l a r s . (140)
A
f u l l range o f p r o j e c t e d I P F growth r a t e s can a l s o be o b t a i n e d if one assumes t h a t
t h e IPF/GNP r a t i o v a r i e s between 0.5 and 1, r e s u l t i n g i n 1990 shipment values o f
between about 3 ( l o w v a l u e ) and 7 ( h i g h v a l u e ) b i l l i o n d o l l a r s .
I n 1976-1977 shipments o f r a d i a t i o n c u r a b l e c o a t i n g s (UV and EB) were $7 t o 12
m i l l i o n , a p p r o x i m a t e l y 0.5% o f t h e t o t a l v a l u e o f i n d u s t r i a l p r o d u c t f i n i s h i n g
shipments f o r t h a t year. (124,141)
I n 1979 t h e shipment f o r r a d i a t i o n c u r a b l e
c o a t i n g s i n c r e a s e d somewhere between 2.4% and 5% o f t h e t o t a l I P F shipments values
($55 t o 114 m i l l i o n ) and i n 1982 and 1985 r a d i a t i o n c u r a b l e c o a t i n g s r e p r e s e n t e d
between 2.8% and 6% ($71 t o 153 m i l l i o n ) and 4.5% and 6% ($168 t o 222 m i l l i o n )
r e s p e c t i v e l y o f t h e t o t a l IPF shipments f o r these y e a r s .
6-1
I f one assumes t h a t i n
Table 6-1
RADIATION PROCESSING END USE MARKETS AND PRODUCTS (134)
End Use Markets
Products
Graphic Arts
Inks (UV, EB)
Photopolymer plates (UV)
Reproduction films (UV)
Paper release coatings (EB)
Decals (UV)
Transfer letters
Coated foils (UV, EB)
Coated films (UV, EB)
Packaging
Inks (UV, EB)
Photopolymer plates (UV)
Overprint coatings (UV, EB)
Shrink films (EB)
Barrier coatings (UV, EB)
Labels (UV)
Tapes (UV, EB)
Album jackets (UV, EB)
Cosmetic cartons (UV)
Liquor cartons (UV)
Closures (UV)
Bottles & bottle caps (UV)
cups (UV)
Cans (UV)
Consumer
Magazines (UV)
Catalogues (UV)
Book covers (UV)
Credit cards (UV)
Decorative mirrors (UV)
Plaques (UV)
Flooring (UV)
Furniture (UV)
Appliances (UV, EB)
Lami nates (EB)
Name plates (UV)
Flocked fabric (EB)
Footwear (EB)
Permanent press (EB)
Transportation
Nameplates (UV, EB)
Assembly parts (EB, UV)
Replacement parts (UV, EB)
Decorative finishes (UV, EB)
Laminations (EB)
Conductive coatings (UV)
Electrical insulation (EB)
Construction
Panels (wood & particle
board) (UV, EB)
Flooring (UV)
Wallpaper (UV)
Binders for abrasives (EB)
Laminations (EB)
Electrical insulation (EB)
Coil coated stock (EB)
Printed circuit inks (UV)
Photopolymer plates (UV)
Photopolymer masks (UV)
Electrical i nsul at ion (EB)
Photo resists (UV)
Wire coatings (UV, EB)
Conductive coatings (UV, EB)
Encapsulation/conformal
coatings (UV, EB)
Speakers (UV)
Fiber optics (UV)
Magnetic tapes (EB)
Dielectric coatings (EB)
Electrical insulation (EB)
Wire & coil bonding (EB)
Electronics
- marking
- etching
(UV)
(UV)
- solder masks
Communi cation
(UV)
Product usually prepared by ultraviolet (UV)
or electron beam (EB) radiation processing
conditions
.
6-2
Q
c
0
I-
I
0
0
F
F
I
0
0
0
I
O
Q)
O
I
0
0
O
0
I
0
O
IC
C
I
0
O
D
I
0
%
F
6-3
I
0
0
d
I
0
0
m
I
I
O
0
O
O
(v
r
1990 r a d i a t i o n c u r a b l e c o a t i n g s w i l l be between 6 and 10% of t h e t o t a l IPF $ m i l l i o n shipment values f o r t h a t year, then t h i s would equate t o a v a l u e f o r t o t a l
r a d i a t i o n c u r a b l e c o a t i n g shipments o f between $374 and $624 m i l l i o n as c a l c u l a t e d
from the relationship:
(0.06 t o 0.10)
( I P F m i l l i o n $ = 0.92 GNP b i l l i o n $1.
A
f u l l range o f p r o j e c t e d values can a l s o be o b t a i n e d u s i n g t h e r e l a t i o n s h i p (0.06 t o
0.10)
(IPF m i l l i o n $ = 0.5 t o 1 GNP b i l l i o n $ 1 (Table 6-2).
R a d i a t i o n c u r a b l e c o a t i n g shipments can be f u r t h e r separated i n t o two major areas:
UV and EB cured c o a t i n g systems.
I n 1976-197_7_the d i v i s i o n f o r t o t a l r a d i a t i o n
c u r a b l e c o a t i n g shipments was 0.4 p e r c e n t f o r UV and 0.1 p e r c e n t f o r EB t e c h n o l ogies.
and 0.3,
I n 1979, 1982, and 1985 t h i s d i v i s i o n became 2.1,
1.2 p e r c e n t f o r EB r e s p e c t i v e l y .
0.6,
2.2,
3.3 p e r c e n t f o r UV
I n t h e year 1990 use o f EB c o a t i n g s
i s expected t o be g r e a t e r than t h e use o f UV c o a t i n g s because o f t h e advantage o f
u s i n g EB over UV p r o c e s s i n g techniques f o r h i g h speed-high volume c o a t i n g
applications.
I n d u s t r i a l p r o d u c t f i n i s h e s can a l s o be d i v i d e d i n t o n i n e market segments:
metal,
wood, t r a n s p o r t a t i o n , machinery, appliance, packaging, p l a s t i c p a r t s , e l e c t r o n i c s
and miscellaneous ( F i g u r e 6-2).
The areas most l i k e l y t o i n c r e a s e t h e i r use o f
UV/EB r a d i a t i o n p r o c e s s i n g techniques a r e t h e wood, metal , packaging, and p l a s t i c
f i n i s h i n g i n d u s t r i e s . (47)
Wood F i n i s h i n g
I n t h e wood f i n i s h i n g i n d u s t r y ( f l a t s t o c k ) t h e consumption o f UV r a d i a t i o n c u r a b l e
c o a t i n g systems f o r 1974-75 was 6,803 m e t r i c t o n s o r 15 m i l l i o n pounds o f material.
T h i s c o n v e r t s t o a p p r o x i m a t e l y 1.1 m i l l i o n g a l l o n s o f c o a t i n g , assuming
a d e n s i t y o f 8 pounds/gallon f o r c l e a r f i n i s h e s (10% o f t h e market o r 1.5
million lbs
"=
200,000 g a l l o n s ) and a d e n s i t y o f 15 pounds/gallon f o r f i l l e r c o a t -
i n g s (90% of t h e market o r 13.5 m i l l i o n pounds
"=
900,000 g a l l o n s ) .
(124)
I n 1981
t h e consumption of UV c u r e d c o a t i n g s f o r t h i s i n d u s t r y was 10 m i l l i o n pounds o r
0.73 m i l l i o n g a l l o n s . (142)
-
The r e c e n t annual decrease i n volume o f m i l l i o n s o f
g a l l o n s shipped f o r t h i s i n d u s t r y ( F i g u r e 6-31 i n d i c a t e s t h a t t h i s market w i l l have
a r e l a t i v e l y low 1990 f i n a l shipment value. (47
L
135) A t t h e p r e s e n t t i m e UV r a d i a t i o n c u r a b l e c o a t i n g s a r e o n l y 5 t o 9% o f t h e p r e f i n i s h e d board shipment v a l u e
(1 t o 2% o f t h e t o t a l wood f i n i s h i n g m a r k e t ) and i n t h i s a p p l i c a t i o n , I R c o a t i n g s
r e p r e s e n t a major t h r e a t t o U V - r a d i a t i o n p r o c e s s i n g systems.
E l e c t r o n beam (EB)
c o a t i n g s a r e n o t c o n s i d e r e d t o be a major p r o d u c t f o r t h i s market because t h e r e q u i r e d c o a t i n g s a r e t h i n enough o r t h e pigment t y p e and l e v e l s a r e such t h a t UV
and I R p r o c e s s i n g techniques can c u r e t h e f i n i s h f o r acceptable p r o d u c t performance
6-4
Table 6-2
ANNUAL SHIPMENT VALUES FOR THE INDUSTRIAL PRODUCT
FINISHING (IPF) MARKET; GROSS NATIONAL PRODUCT
(GNP) VALUES AND IPF/GNP RATIOS (135-139)
I n d u s t r i a1 Product
F i n i s h e s (IPF)
( m i l $1
Gross N a t i o n a l
Product (GNP)
( b i l $1
1977
1961
1918
1.02
1978
2092
2156
0.97
1979
2284
2414
0.95
1980
2418
2626
0.92
1981
2737
2926
0.93
1982
2546
3085
0.83
1983
2907
3400
0.86
1984
3428
3790
0.90
1985
3705
4265
0.87
6785
1990
IPF m i l $
0.92 h i s t o r i c a l average (GNP b i l $)
IPF m i l $
0.5 (6785) = 3121 (1990 low value)
IPFf
mil
$ 2 1 (6785) = 6785 (1990 high value)
6-5
I P F(GN P
AVG IPF MARKETS
A
6
C
D
E
F
G
= Metal Coatings
= Coil Coatings
=
Wood Coatings
= Transportation
= Machinery
= Appliance
= Packaging
H = Plastlcs
I = Electronics
J = Miscellaneous
Figure 6-2.
15.5%
9.5%
21 .O%
18.5%
8.0%
3.5%
10.5%
7.0%
3.5%
3.0%
Major Market Segments f o r I n d u s t r i a l Product Finishes
6-6
(47)
F
ia
a
6-7
levels.
The f u t u r e f o r UV r a d i a t i o n processing i s i n t h e area o f three-dimensional
f i n i s h i n g o p e r a t i o n s which o f f e r a v e r y a t t r a c t i v e growth o p p o r t u n i t y f o r t h e t e c h -
If one assumes t h a t t h e p e n e t r a t i o n o f UV r a d i a t i o n p r o c e s s i n g i n t o t h e
p r e f i n i s h e d board market w i l l remain c o n s t a n t (1 m i l l i o n g a l l o n s ) t h r o u g h 1990,
nology.
I f UV
t h e n t h i s would equate t o a shipment v a l u e o f $24 m i l l i o n f o r t h a t year.
r a d i a t i o n processing p e n e t r a t e s t h e t h r e e dimensional f i n i s h i n g market area and
i n c r e a s e s t h e volume of c o a t i n g s shipped t o 2 m i l l i o n g a l l o n s i n 1990 t h e n t h i s
would equate t o a shipment v a l u e o f a p p r o x i m a t e l y $48 m i l l i o n f o r t h e y e a r 1990.
These p r o j e c t i o n s are made an. t h e assumptions t h a t t h o o v e r a l l wood f i n i s h i n g i n d u s t r y market growth w i l l remain c o n s t a n t (39 m i l l i o n g a l l o n s =- $234 m i l l i o n v a l u e )
o r have a c o a t i n g shipment v a l u e i n 1990 v e r y s i m i l a r t o t h a t observed i n 1985
( T a b l e 6-31,
Metal D e c o r a t i v e Coatings
The t o t a l metal f i n i s h i n g market segment f o r IPF has i n c r e a s e d ( 5 % o v e r a l l average
annual i n c r e a s e ) f r o m 80 m i l l i o n g a l l o n s o f c o a t i n g s shipped i n 1980 t o 98 m i l l i o n
o f g a l l o n s shipped i n 1985.
T h i s market segment can a l s o be s u b d i v i d e d i n t o f o u r
separate product l i n e s (can-container coatings, c o i l coatings, f u r n i t u r e - f i x t u r e s ,
and general m e t a l s ) ; t h e can-container and general metals c o a t i n g s a r e o f most
i n t e r e s t t o c u r r e n t r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s ( F i g u r e 6-4).
(47
135)
A
R a d i a t i o n c u r a b l e shipments were 8 m i l l i o n pounds (1 m i l l i o n g a l l o n s ) i n 1974 and
10 m i l l i o n pounds (1.25 m i l l i o n g a l l o n s ) i n 1981.
These shipment values r e p r e s e n t
a p p r o x i m a t e l y 2 t o 3% of t h e combined c o n t a i n e r c o a t i n g s and general m e t a l markets
b u t a r e o n l y 1 t o 2% of t h e t o t a l metal f i n i s h i n g market segment. (124,142)
The h i s t o r i c and p r o j e c t e d growth r a t e f o r t h i s market segment i s shown i n Table
6-4.
The combined c o n t a i n e r and general m e t a l market areas a r e p r o j e c t e d t o i n -
crease f r o m 5 1 m i l l i o n g a l l o n s (1985) t o 80 m i l l i o n g a l l o n s (19901, which equates
t o a p p r o x i m a t e l y $584 m i l l i o n combined c o a t i n g shipments f o r t h a t y e a r .
I f one
assumes t h a t i n 1990 r a d i a t i o n c u r a b l e c o a t i n g shipment w i l l be between 1 and 4
m i l l i o n g a l l o n s (1 t o 5% of t h e combined c o n t a i n e r
-
general metal volume s h i p -
ments) t h e n t h i s would equate t o between $24 and 96 m i l l i o n ( 4 t o 16% o f t h e comb i n e d c o n t a i n e r and general metal markets, and 2 t o 8% o f t h e t o t a l metal f i n i s h i n g
market segment d o l l a r v a l u e s ) f o r t h a t y e a r . (140-142)
6-8
Table 6-3
ANALYSIS OF CONVENTIONAL AND RADIATION CURABLE COATINGS
FOR WOOD FINISHING MARKET AREAS (47,135,140,141)
IPF Market Seqment
Years
Shipment ,
Million
o f Gal 1 ons
Million
of Pounds
Million
o f $3
Historical
Wood Finishes
Total
1980- 1985
73-39
438-234
Furniture and
Fixtures
1980-1985
53-27
318-162
Prefi ni shed
1980- 1985
20-12
120-72
1975- 19$1
1-0.7
UV-Radiation Curable
15-10
24-17
Future
Wood Finishes Total
1990
39
UV-Radiati on Curable
1990
1-2
234
15-30
24-48
a$6/gallon conventional coatings, 12-35 $/gallon radiation curable coatings.
6-9
3
=.2s0i
C O
iih
-01
Om
- w
P
-2
s
g
0
I-
6-1 0
Table 6-4
ANALYSIS OF CONVENTIONAL AND RADIATION CURABLE
COATINGS FOR METAL FINISHING MARKET AREAS (47.140.141)
I P F Market Sesment
Years
Shipment,
Mill ion
of Gal 1 ons
Mill ion
of Pounds
Mil 1 ion
o f 79-80s
Historical
Metal Finishes
Tot a1
1980-1985
80- 98
569-700
Can-container
1980-1985
35-41
249-292
Coi 1 coatings
1980-1985
25-37
183- 271
Furniture
fixtures
1980-1985
10-10
70-70
General metals
1980-1985
10-10
67-67
Radi at i on curabl e
coatings
1979-1981
1-1.25
8-10
24-30
Future
Metal Finishes Total
1990
160
1174
Can-container
1990
60
450
Coi 1 coatings
1990
60
450
Furniture fixtures
1990
20
140
General metals
1990
20
134
Radiation curable
coatings
1990
1-4
6-1 1
8-32
30-96
Pack ag ing C o a t i ngs
The packaging i n d u s t r y (paper, f o i l , p l a s t i c f i l m ) has shown an i n c r e a s e i n c o a t i n g
shipments f r o m 20 m i l l i o n g a l l o n s ($130 m i l l i o n v a l u e ) i n 1980 t o 35 m i l l i o n g a l l o n s i n 1985.
-
A l i n e a r e x t r a p o l a t i o n f r o m 1980 t o 1990 f o r t h i s i n d u s t r y p r o j e c t s
t h a t t h e volume of c o a t i n g s shipped i n 1990 c o u l d r e a c h 55 m i l l i o n g a l l o n s valued
a t $403 m i l l i o n ( F i g u r e 6 - 5 ) .
R a d i a t i o n c u r a b l e c o a t i n g s used i n t h i s i n d u s t r y i n
1979-1981 were valued a t between $6 and $22 m i l l i o n and a r e expected t o i n c r e a s e up
t o a maximum of $118 m i l l i o n (between 5 and 29 p e r c e n t o f t h e t o t a l packaging s h i p ment v a l u e ) in.1990 ( T a b l e 6 4 ) . (47-,14@,141JTable 6-5
ANALYSIS OF CONVENTIONAL AND RADIATION CURABLE COATINGS
FOR PACKAGING MARKET AREAS (47,141 1
I P F Market Segment
Years
Shipment ,
M i 11 i o n
of G a l l o n s
M i 11 i o n
o f Pounds
M i l 1i o n
o f 79-80$
H is t o r i c a l
Packaging (paper,
f o i l , plastic
film)
1980-1985
R adi a t ion c u r a b l e
coatings
1974-1980
130-257
20-35
2-8
6- 22
Future
Pack ag ing
1990
Radiation curable
coatings
1990
35-55
257-403
8-43
22-118
Other C o a t i n g Systems
I n 1976 o n l y f o u r commercially o p e r a t i v e f l o o r i n g l i n e s i n t h e U.S.
used UV c u r i n g
technology, b u t b y 1985 a l l o f t h e major f l o o r i n g manufactures had e x p l o r e d some
aspect o f t h e commercial u t i l i z a t i o n o f t h i s technology.
The consumption o f UV
c u r a b l e c o a t i n g s i n 1979 was about 10 m i l l i o n pounds ($32 m i l l i o n ) ; i n 1985 t h i s
grew t o a p p r o x i m a t e l y 16 m i l l i o n pounds ($50 m i l l i o n ) .
T h i s consumption o f UV
c u r a b l e c o a t i n g s r e p r e s e n t s a p p r o x i m a t e l y 10 t o 16% o f t h e t o t a l c o a t i n g products
used i n t h e manufacture o f v i n y l f l o o r i n g p r o d u c t s .
6-1 2
A l l o t h e r segments o f t h e I P F
~
-
6-1 3
market ( c o a t i n g s f o r f l e x i b l e p l a s t i c s , elastomers, i n c l u d i n g f l o o r c o a t i n g s , and
o t h e r m a r k e t s ) accounted f o r between $69 and $100 m i l l i o n shipment values o f r a d i a t i o n c u r a b l e c o a t i n g s f o r t h e years 1979-1982 and a r e expected t o i n c r e a s e f r o m
a p p r o x i m a t e l y $100 t o $140 m i l l i o n i n 1990. (47,124,134,135,141,142)
PRINTING
The h i s t o r i c growth of t h e p r i n t i n g i n k i n d u s t r y i s shown i n F i g u r e 6-6 and t h e
breakdown o f 1982 d o l l a r v a l u e shipments among t h e f i v e m a j o r p r i n t i n g processes i s
shown -in Figure 6-7.
(135,140,143)
The t o t a r - m t n i o n d o l l a r shipment v a l u e f o r
t h i s i n d u s t r y can be p r o j e c t e d t o t h e year 1990 b y t h e f o l l o w i n g r e l a t i o n s h i p der i v e d f r o m t h e i n f o r m a t i o n c o n t a i n e d i n Table 6-6 and F i g u r e 6-6.
P r i n t i n g I n k ( P I ) ( $ m i l l i o n shipments)
"=
0.41 (GNP $ b i l l i o n )
Thus i n t h e year 1990 t h e expected t o t a l shipment v a l u e f o r t h i s i n d u s t r y s h o u l d be
a p p r o x i m a t e l y $2,782 m i l l i o n .
R a d i a t i o n c u r a b l e i n k s and o v e r p r i n t varnishes a r e m a i n l y used i n t h e packaging
and p r i n t i n g t r a d e consumption market areas.
about 40% o f a l l i n k s consumed i n t h e U.S.
Packaging i n k s o f a l l t y p e s make up
The t h r e e m a j o r packaging submarkets
are the following:
0
0
0
metal and p l a s t i c c o n t a i n e r s
f o l d i n g paper c a r t o n s
1abel s
.
P u b l i c a t i o n i n k s a r e used t o p r i n t newspapers, magazines, and books, and consume
a p p r o x i m a t e l y 20% o f t h e nonpackaging i n k markets; 40% of t h e nonpackaging i n k s a r e
used i n t h e commercial f i e l d f o r p r i n t i n g commercial f l y e r s , d i r e c t m a i l , ads,
business forms, e t c .
Between t h e years o f 1975 and 1981 r a d i a t i o n c u r a b l e i n k s
i n c r e a s e d f r o m 1.75 m i l l i o n pounds shipped t o 18 m i l l i o n pounds shipped w i t h a
shipment v a l u e i n c r e a s e o f between $5.33 and $54 m i l l i o n o r between 0.8 t o 4% o f
t h e t o t a l P I shipment v a l u e f o r those y e a r s .
I f one assumes t h a t t h e use o f r a d i a -
t i o n c u r a b l e i n k s w i l l v a r y f r o m 4 t o 10% i n 1990 t h e n t h e p r o j e c t e d shipment v a l u e
f o r t h i s y e a r would be between $111 t o $278 m i l l i o n ( a p p r o x i m a t e l y 70% o f these
values r e l a t e t o packaging i n k market areas; 30% o f t h e s e values r e l a t e t o o t h e r
nonpackaging p r i n t i n g market segments) ( T a b l e 6-7).
6-1 4
(47,141,142)
6-1 5
/
offset
39%
//
I
\
Other
Screen
4%
I
Flexographic
18%
Letterpress
9%
Total 1982 U.S. Shipments = $1.36 to 1.48 Billion
Figure 6-7.
Processes
Market Share o f Major Printing
(E)
6-1 6
Table 6-6
ANNUAL SHIPMENT VALUES FOR PRINTING INKS; GROSS
NATIONAL PRODUCT VALUES AND P I / G N P RATIOS (135,140)
Year
P r i n t i n g Inks
( P I ) ( m i l $)
Gross N a t i o n a l Product
(GNP) ( b i l $1
PI/GNP
1977
905
1918
0.47
1978
1000
2156
0.46
1779
1110
2414
0.46
1980
1250
2626
0.48
1981
1380
2926
0.47
1982
1495
3085
0.48
1983
1540
3400
0.45
1984
1595
3790
0.42
1985
1990
P I ( m i l $1
6785
9
0.41 h i s t o r i c a l average (GNP b i l $1.
6-1 7
Table 6-7
CONVENTIONAL AND RADIATION CURABLE PRINTING INK
INDUSTRY MARKET ANALYSIS (47,124,141,142)
-Year
Mil Pounds
Mil $ Shipped
(Percentage o f total
PI shiPment values)
Hi stori cal
Printing ink (PI)
industry total
1984
Radi at i on curable
inks
1975
1595
1.75
1977
5.33 (0.8 percent)
15 (1.7 percent)
1979
6
1981
18
20 (1.8 to 2 percent)
54 (4 percent)
Future
Printing ink
industry total
1990
2782
Radiation curable
inks
1990
1 1 1 to 278 (4 to 10
percent)
6-1 8
I n a r e l a t e d area, p r i n t i n g p l a t e s can be manufactured v i a photopolymer t e c h n o l ogies and i n 1969-1975 t h e t o t a l market f o r a l l types o f s e n s i t i z e d p r i n t i n g
p l a t e s , i n c l u d i n g UV-cured p r i n t i n g p l a t e s , was between $675 m i l l i o n and $1 b i l lion.
R a d i a t i o n ( U V ) c u r a b l e m a t e r i a l s accounted f o r a p p r o x i m a t e l y 8 t o 17% o f
t h i s market i n 1975-1979 ( 8 m i l l i o n pounds valued a t $120 m i l l i o n ) and i n 1985 was
a p p r o x i m a t e l y 14 m i l l i o n pounds o r $210 m i l l i o n i n value.
T h i s market i s expected
t o grow between $210 and $250 m i l l i o n i n v a l u e f o r t h e y e a r 1990. (124,141)
ADH ES I VES
-
The adhesive i n d u s t r y ( F i g u r e 6-8), s p e c i f i c a l l y t h e s y n t h e t i c and rubber adhesive
p r o d u c t l i n e s , can be p r o j e c t e d t o grow f r o m $1880 m i l l i o n shipment values i n 1982
up t o $4139 m i l l i o n i n 1990 a c c o r d i n g t o t h e r e l a t i o n s h i p s y n t h e t i c and rubber
adhesives ( A D ) ( m i l l i o n d o l l a r shipment v a l u e ) = 0.61 (GNP b i l l i o n d o l l a r )
d e s c r i b e d i n Table 6-8.
(135,140,144)
R a d i a t i o n c u r a b l e t o t a l adhesives (UV and
E B ) shipment values i n 1983/84 were 5 m i l l i o n d o l l a r s f o r UV and $1.8 t o $2.2 m i l l i o n f o r EB.
These values are p r o j e c t e d t o grow up t o $11 m i l l i o n ( U V ) and $8
m i l l i o n (EB) f o r t h e year 1990 ( T a b l e 6-9).
UV c u r a b l e adhesives, such as s t r u c -
t u r a l adhesives (nonpressure s e n s i t i v e ) f o r t h e e l e c t r o n i c s , automotive, and medic a l d e v i c e i n d u s t r i e s , are e l i m i n a t i n g o f f - l i n e c u r i n g o p e r a t i o n s b y i n c o r p o r a t i n g
c u r i n g i n t o a f u l l y automated assembly o p e r a t i o n .
I n 1983/84 L o c t i t e i n t r o d u c e d 11
new UV-curable adhesive systems and a s s o c i a t e d a p p l i c a t i o n equipment ( c o s t
$50-500,000)
f o r these market areas.
been d o u b l i n g y e a r l y s i n c e 1979.
f r o m $4 t o $10/lb.
The demand f o r L o c t i t e ' s cured adhesives has
The c o s t o f t h e s e s t r u c t u r a l adhesives ranges
I n 1983 t h e market f o r UV-cured s t r u c t u r a l adhesives alone was
about $1 m i l l i o n and i s expected t o grow t o 1.25 m i l l i o n d o l l a r s i n 1990. (144-146)
Pressure s e n s i t i v e adhesives ( P S A ) are a l s o a l a r g e p o t e n t i a l s p e c i a l t y market f o r
r a d i a t i o n cured polymers.
p e r y e a r ( F i g u r e 6-9).
This market i s i n c r e a s i n g a t about t h e r a t e o f 10 t o 11%
(147)
PLASTICS AND RUBBER MATERIALS
T o t a l p l a s t i c s p r o d u c t i o n i n t h e U.S.
has grown f r o m a p p r o x i m a t e l y 38 b i l l i o n
pounds i n 1981 t o almost 50 b i l l i o n pounds i n 1985.
The two most i m p o r t a n t polymer
m a t e r i a l s o f i n t e r e s t f o r r a d i a t i o n processing m o d i f i c a t i o n s are polyethylene (lowd e n s i t y ) and p o l y v i n y l c h l o r i d e , which have a l s o i n c r e a s e d t h e i r combined t o t a l
p r o d u c t i o n r a t e s f r o m 14 b i l l i o n pounds i n 1981 t o 16 b i l l i o n pounds i n 1985
( F i g u r e 6-10).
6-11.
The market d i v i s i o n s f o r these two m a t e r i a l s i s shown i n F i g u r e
(135,148)
6-1 9
6-20
Table 6-8
HISTORICAL GROWTH OF SYNTHETIC AND RUBBER ADHESIVES (AD);
GNP VALUES AND AD/GNP RATIOS (135,140)
S y n t h e t i c and Rubber
Adhesives, (AD)
M i l $ shimed
1977
1978
1979
1980
1981
1982
- ...- ...
1222
1367
1506
1545
1667
1aao
GNP
Bil $
AD/GNP
1918
2156
2414
2626
2926
3085
0.64
0.63
0.62
0.59
0.57
0.61
6785
1990
S y n t h e t i c and r u b b e r adhesives (AD) ( m i l $ shipment v a l u e )
average v a l u e (GNP b i l l $ ) .
=
0.61 h i s t o r i c
T a b l e 6-9
CONVENTIONAL AND RADIATION CURABLE SYNTHETIC AND RUBBER
ADHESIVE MARKET ANALYSIS (47,141)
H istoric
S y n t h e t i c and
r u b b e r adhesives
Pounds
Consumed
Year
Millions o f
$ shimed
1880
1982
Radiation curable
adhesives
uv
EB
1983184
1983184
76,00o-a5,000
0.5 m i l l i o n
5
1.8 t o 2.2
Future
S y n t h e t i c and
r u b b e r adhesives
4139
1990
Radiation curable
adhesives
uv
EB
1990
1990
290,000
1.3 m i l l i o n
6-21
11
a
,--
Total PSA
Market
350
300
250
200
150
1975
Figure 6-9.
1980
Shipments o f Pressure S e n s i t i v e Adhesives
6-22
1985
(147)
Total Plastics
Production
45
40
u)
0
35
C
3
2
30
r
0
E
.--
t
25
I
20
15
10
t
Low Density Polyethylene
5
1981
1982
1983
1984
1985
Share o f Low D e n s i t y P o l y e t h y l e n e (LDPE) and P o l y v i n y l C h l o r i d e
F i g u r e 6-10.
(PVC) Annual P l a s t i c s P r o d u c t i o n C a p a c i t y (135)
6-23
100
Extruded
Items
Film and
Sheet
I
L
67%
53%
All
Others
Extrusion
Coatings
_.
I
Injection
Molding
Wire and
Cable
Figure 6-11.
; I
I
Calendered
Sheet
All Others
r
Molded
Items
Coatings
1985 Market Share f o r Low Density Polyethylene (LDPE) and Polyvinyl Chloride (PVC)
l~
(148)
I
I t i s d i f f i c u l t t o p r o j e c t t h e a c t u a l growth o f h i g h energy r a d i a t i o n m o d i f i e d
r u b b e r and p l a s t i c m a t e r i a l s a t t h i s time, b u t a general overview o f t h e s e indust r i e s can be d e s c r i b e d i n a s e m i q u a n t i t a t i v e manner.
To date, p l a s t i c s consumption
i n t h e U n i t e d S t a t e s as a whole has grown h i s t o r i c a l l y a t r a t e s i n excess o f GNP.
Rubber consumption, however, has n o t m a i n t a i n e d t h i s t r e n d (Table 6-10).
(135,149)
D u r i n g t h e 1 9 7 0 ' s rubber consumption grew a t r a t e s o f a p p r o x i m a t e l y 0.5-0.7
GNP.
I n t h e 1 9 8 0 ' s t h i s r a t i o has d e c l i n e d even f u r t h e r and
that of
has become n e g a t i v e .
These t r e n d s i n d i c a t e t h a t t h e o p p o r t u n i t i e s f o r r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s
a r e expected t o be g r e a t e r i n t h e p l a s t i c s i n d u s t r y t h a n i n t h e r u b b e r i n d u s t r y
~~
marketplace.
I t s h o u l d be noted, however, t h a t two companies (Raychem C o r p o r a t i o n
and t h e Cryovac D i v i s i o n o f W. R. Grace) have combined s a l e s o f a t l e a s t $400
m i l l i o n per year m a n u f a c t u r i n g p o l y o l e f i n h e a t - s h r i n k a b l e sleeves, t u b i n g , boots,
wrap and r a d i a t i o n c r o s s - l i n k e d p o l y e t h y l e n e heat s h r i n k a b l e f o o d wrap
p r o d u c t s . (150)
ELECTRONICS AND COMMUNICATIONS
The growth o f t h e e l e c t r o n i c s i n d u s t r y i s b e s t r e p r e s e n t e d by t h e growth o f spec i f i c i n d i v i d u a l components , such as i n t e g r a t e d c i r c u i t s ( I C ) ( F i g u r e 6-1 2 ) . The
1984 d o l l a r e s t i m a t e o f e l e c t r o n i c chemicals usage ( d e v i c e s and e n c a p s u l a n t s ) i n
t h e U.S.
i s shown i n F i g u r e s 6-13,
6-14,
and 6-15.
(151,152)
The e l e c t r o n i c s and m i c r o e l e c t r o n i c s i n d u s t r i e s use c o a t i n g s , adhesives, and i n k s
f o r a wide range o f a p p l i c a t i o n s b u t p r i m a r i l y f o r p r i n t e d c i r c u i t boards (PCB).
Some of t h e c a t e g o r i e s o f systems used i n t h e s e i n d u s t r i e s a r e as f o l l o w s :
0
e
0
0
0
0
UV c u r a b l e screen i n k s
L i q u i d p h o t o r e s i s t s f o r PCB and i n t e g r a t e d c i r c u i t s
L i q u i d s o l d e r marks (UV c u r a b l e )
L e t t e r i n g and nomenclature i n k s
Conformal c o a t i n g s
Dry f i l m r e s i s t s and s o l d e r marks.
I n 1975-76 t h e p h o t o r e s i s t p r i n t e d c i r c u i t board markets used a p p r o x i m a t e l y $41
m i l l i o n w o r t h o f i n k s , i n c l u d i n g UV c u r a b l e m a t e r i a l s .
Assuming t h a t 10% o f t h e
market was c a p t u r e d b y UV-curing i n k s , t h e n t h i s equates t o t h e market value f o r
UV-curing i n k s i n t h e s e a p p l i c a t i o n s o f about $4 m i l l i o n i n t h e U n i t e d
S t a t e s . (124)
I n 1979-81-85 t h e volume o f UV c o a t i n g s and i n k s was 8, 12 and 14
m i l l i o n pounds, r e s p e c t i v e l y , r e p r e s e n t i n g a market v a l u e o f between $93 m i l l i o n
and $160 m i l l i o n f o r t h i s segment o f t h e i n d u s t r y .
Because o f t h e r a p i d growth f o r
h i g h t e c h n o l o g y areas such as demonstrated b y t h e computer and communication
i n d u s t r i e s , t h e use o f r a d i a t i o n c u r a b l e m a t e r i a l s i n t h e year 1990 i s expected t o
6-25
Table 6Synthetic and Natural Rubber Consumption (135)
-
U.S.
S y n t h e t i c Rubber
Consumption ( m i l l i o n s m e t r i c t o n s )
m
I
N
m
Year
-
Total
-
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
2.00
1.84
1.73
2.10
2.01
2.49
2.59
2.51
2.26
1.99
2.20
2.41
2.31
2.17
1.99
2.09
(ex
.-SBRia t e x )
Latex
-
SBR
Butyl
Neoprene
Nitrile
Polyb u t ad; ene
.09
.08
.13
.28
.22
.27
.24
.23
.23
.13
.12
.10
.12
.13
.12
.ll
.09
.12
.12
i4
.15
.05
.07
.07
.06
.06
.06
.07
.06
.06
.07
.08
.06
.06
.06
.07
.36
.27
.35
.31
.41
.41
.41
.34
.32
.35
.35
.31
.29
.28
.27
.14
.09
.15
.11
.14
.15
.14
3
4
19
14
8
2
.80
.88
1.02
1.03
1.32
1.42
1.45
1.30
1.19
1.28
1.48
1.47
1.39
1.24
1.34
.15
.16
.14
.16
-09
.12
.13
.13
.12
.12
.14
.10
.16
.17
.17
.14
.16
-15
.15
.15
.15
.13
44
63
5
6
15
5
6
6
.ll
.
.18
EPR
-
.ll
.09
.10
.09
.07
.05
.05
.04
Percent t o T o t a l
1983
1970
”
-L
.
I 1 i I
I
N a t u r a l Rubber
ConsumDtion
(10’ M e t r i c Tons)
.75
.68
.66
.63
.59
.74
.69
.71
.66
.61
.65
.62
.58
.52
.51
.54
Total
2.75
2.54
2.43
2.52
2.44
3.08
2.90
3.06
2.63
2.45
2.79
2.80
2.66
2.25
2.38
Synthetic
Rubber
as % o f
Total
74
75
76
77
77
76
77
76
75
75
77
78
78
77
77
104
103
u)
g
102
r
0
u)
C
-.-.-0
a
10’
10 0
1970
1975
1980
1985
1990
Year
Figure 6-12.
IC Shipments
6-27
(151)
1995
1984 Estimate $3 Billion
Figure 6-13.
U.S. Electronic Chemicals
6-28
3
6-29
6-30
be 28 m i l i o n pounds valued a t $320 m i l l i o n . (47,134,141)
I n genera
, the
t o t a l use o f e l e c t r o n i c chemicals f o r U.S.
i n d u s t r i e s i n 1984 i s
e s t i m a t e d t o be $3 b i l l i o n ( F i g u r e 6-13) and c o u l d r e a c h $15 b i l l i o n i n t h e y e a r
1990.
I n a r e l a t e d electronics/communication area t h e use o f r a d i a t i o n c u r a b l e
m a t e r i a l s f o r magnetic r e c o r d i n g media was $7 m i l l i o n i n 1983 ( T a b l e 6-11) and i s
e s t i m a t e d t o grow t o $10 m i l l i o n i n 1990.
(105)
Table 6-11
(105)
MAGNETIC M E D I A MARKET
1983
Factory
s a1es(Million $1
Growth
'82-'83
Percent
Audio Media
2,050
8
Video Media
3,150
22
Computer & I n s t r u m e n t Tape
550
14
F l e x i b l e Disks
653
26
495
6,898
27
R i g i d Disks
A complete summary o f p a s t and p r o j e c t e d markets f o r r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s i n t h e U.S.
i s shown i n Table 6-12.
RADIATION PROCESSING EQUIPMENT
As more and more i n d u s t r i e s c o n v e r t t o r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s , t h e demand f o r r a d i a t i o n p r o c e s s i n g equipment i n c r e a s e s p r o p o r t i o n a l l y .
It i s estimated
t h a t r a d i a t i o n p r o c e s s i n g equipment (UV, h i g h energy e l e c t r o n , I R ) w i l l grow f r o m
a p p r o x i m a t e l y 3035 t o t a l p r o d u c t i o n u n i t s i n 1980-81 t o a p p r o x i m a t e l y 8610 t o t a l
p r o d u c t i o n u n i t s i n t h e y e a r s between 1986 t o 1990.
The growth ( h i s t o r i c and
f u t u r e ) and major market usage f o r these p a r t i c u l a r r a d i a t i o n p r o c e s s i n g equipment
systems i s shown i n Table 6-13.
(134)
6-31
Table 6-12
RADIATION PROCESSING OF POLYMERIC MATERIALS
MARKETS AND GROWTH POTENTIAL
Histories (1979-1985)
Mi 11 ions.
Rounds
dol 1 ars
Mi 11 ions.
Wood Coatings
Metal Coatings
Packaging Coatings
F1 oor Coatings
W i re Coati ngs
Flexible Plastics
Elastomer Coatings
Other Markets (Fiber Optics,
Ceramics, Textiles)
10-15
8-10
2-8
10-16
0.1
4-5
2
17-24
24-30
6-22
32-50
Future (19901
Millions,
Mi 11 ions,
pounds
dol 1 ars
12-14
5-6
15-30
8-32
8-43
16-19
0.1-0.2
5-9
2
24-48
30-96
32-96
50-60
-14-24
6
5-12
20-30
12-20
30-50
Sub Total (IPF Market Ranges)
41-68
116- 176
66-155
176-398
Printing Inks
Printing Plates
Adhesives
Electronics
Magnetic Recording Materials
18
8-14
0.6
8-14
54
120-210
6.8-7.2
93-160
7
54- 135
14-17
1.6
28
--
1 1 1 - 278
210-250
19
320
10
Sub Total (Predominately
UV and Low Energy
Electron Processing
Operations)
76-115
281 -438
98-182
670-877
High Energy Electron Beam
Appl i cati ons
Infrared Curing Applications
Total Dollar Value
--
--
---
400-700
lo
691 - 1,148
6-32
---
700-900
20
1,390-1,797
Table 6-13
RADIATION PROCESSING EQUIPMENT
(GROWTH AND MAJOR MARKET AREAS) (134)
-
Approximate
Number of P r o d u c t i o n U n i t s
..
F o r a ' G i v e n Year
Processing Equipment and
Major Market Area
54 p e r c e n t i n p r i n t i n g o r
packaging, 23 p e r c e n t i n wood
c o a t i n g s , 23 p e r c e n t i n o t h e r
appl ic a t ion areas
1971
1976
i98o-ai
1986-1990
100
300
2100
4200
2
3
a5
210
850
4200
High Energy E l e c t r o n i c s
Major market areas a r e i n h i g h
speed c o a t i n g and g r a p h i c s a r t s ,
adhesive l a m i n a t i o n , and polymer
m o d i f i c a t i o n techno1 o g i e s
40 p e r c e n t i n metal c o a t i n g s
( t r a n s p o r t a t i o n ) 60 p e r c e n t i n
p l a s t ics , t e x t il e s adhesives ,
c o a t i n g s (nonmetal 1, and t h e
graphic arts industries
-
-
-
-
102
303
3035
a610
Total
6-33
The p r e s e n t and f u t u r e e l e c t r i c a l energy consumption requirements f o r I R , UV, and
high-energy e l e c t r o n processing equipment can be c a l c u l a t e d assuming t h a t an average e s t i m a t e d power c a p a c i t y r a t i n g p e r u n i t f o r each r a d i a t i o n processor c l a s s i f i c a t i o n (UV, EB and IR) i s 100, 50 and 250 kw r e s p e c t i v e l y .
T h i s equates t o an
approximate p r e s e n t t o t a l c a p a c i t y o f 426,750 kw f o r t h e 3035 1980-1981 p r o d u c t i o n
u n i t s and a f u t u r e c a p a c i t y p r o j e c t i o n o f a p p r o x i m a t e l y 1,480,500
kw f o r t h e r a d i a -
t i o n p r o d u c t i o n u n i t s expected t o be i n p l a c e between 1986 and
1990. ( 16,123,134
,150)
COMPETITION FROM EXISTING AND EMERGING TECHNOLOGIES
S e v e r a l competing and emerging t e c h n o l o g i e s a r e a s s o c i a t e d w i t h t h e c o a t i n g s
t r y which impact t h e f u t u r e o f r a d i a t i o n p r o c e s s i n g systems.
ndus-
These competing c o a t -
i n g systems i n c l u d e c o n v e n t i o n a l low s o l i d s solvent-based c o a t i n g s u s i n g s o l v - n t
b u r n i n g o r r e c l a m a t i o n a n t i p o l l u t i o n techniques, h i g h s o l i d s c o n t e n t solvent-based
c o a t i n g s , water-based c o a t i n g s ( e l e c t r o c o a t i n g and n o n e l e c t r o c o a t i n g ) and 100%
s o l i d s powder c o a t i n g systems.
A breakdown o f 1982 and p r o j e c t e d 1987 U.S.
ship-
ments f o r t h e i n d u s t r i a l p r o d u c t f i n i s h i n g market o f t h e c o a t i n g s i n d u s t r y i s shown
i n T a b l e 6-14.
From t h i s i n f o r m a t i o n i t appears t h a t t h e o t h e r c o a t i n g t e c h n o l -
o g i e s w i l l c o n t i n u e t o dominate t h i s p a r t i c u l a r market area. (47)
An energy analy-
s i s f o r c u r i n g these c o a t i n g systems shows t h a t r a d i a t i o n p r o c e s s i n g i s by f a r t h e
most e f f i c i e n t process; however, energy c o n s e r v a t i o n i s n o t t h e o n l y f a c t o r d r i v i n g
t h e c o a t i n g i n d u s t r y t o u t i l i z e t h e s e thermal c u r i n g processes ( T a b l e 6-15).
As
l o n g as t h e r e i s an abundant s u p p l y o f f o s s i l f u e l , t h e c o a t i n g i n d u s t r y w i l l
c o n t i n u e t o f i n i s h p r o d u c t s i n which t h e r e i s no v a l u e added o r m a n u f a c t u r i n g
advantage o t h e r than energy savings by c o n v e n t i o n a l thermal c u r e methods.
6-34
(153)
Table 6-14
U.S. SHIPMENTS OF INDUSTRIAL FINISHES BY
COATINGS MATERIALS AND SYSTEMS (47)
1982
~ _ _ _ _ _
- __--
1987a
Coatinqs Material/Svstem
Mil $
Percent
Mil $
Sol ventborne
Conventional
EPA conforming systems
1670
800
870
65.6
31.4
34.1
830
300
530
34.6
12.5
22.1
Waterborne
Electrodeposition (ED)
Non - ED
500
100
400
19.6
3.9
15.7
800
150
650
33.3
6.3
27.0
Powder coatings
150
5.9
200
8.3
70
55
15
2.8
2.2
0.6
120
50
5.0
2.9
2.1
156
6.1
450
18.8
Radiation curable
U l t r a v i o l e t (UV)
Elec tro n beam (EB)
High sol id s -1 i q u i d
Total
2546
100
aThese values a r e i n constant 1982 d o l l a r s .
6-35
70
2400
Percent
100
Table 6-15
ENERGY ANALYSIS OF COATING TECHNOLOGIES
Sol v e n t
Based
Energy requirements
t o c u r e 440 square
f e e t o f 19-gauge
metal per minute
( m i l l i o n BTU's)
Water- High
borne Sol i d s
--
12
11-12
0
Percent energy
savings
0-8%
Two
Component
Urethane
Electrocoating
Powder
9-10
3
8
8- 10
16-25
75
33
16-33
Radia t ion
Curable
1
90
An emerging t e c h n o l o g y developed by Ashland Chemical Company u t i l i z e s a
low-temperature chemical c u r i n g c o a t i n g system based on b l o c k e d i s o c y a n a t e chemi s t r y c a t a l y z e d b y a v o l a t i l e amine c a t a l y s t m a t e r i a l .
T h i s vapor c u r e process
o f f e r s s e v e r a l advantages over b o t h r a d i a t i o n c u r a b l e c o a t i n g s and t h e r m a l l y cured
c o a t i n g s systems.
I n t h i s technology t h e c o a t i n g i s a p p l i e d f r o m s o l v e n t b u t c o u l d
be designed t o be 100% r e a c t i v e and i s cured b y passing t h e coated p r o d u c t through
a vapor o f t h e amine c a t a l y s t .
t o remove t h e s o l v e n t .
No heat i s r e q u i r e d , except f o r what i s necessary
T h i s vapor c u r e system i s o p e r a b l e f o r a wide v a r i e t y o f
f l a t - and three-dimensional
product configurations.
Both t h e automotive and t h e
v i n y l f i l m i n d u s t r i e s use t h i s technology t o process c e r t a i n p r o d u c t s , and i n
A u s t r a l i a t h i s system has been adapted t o c u r e p r i n t i n g i n k s f o r a wide v a r i e t y o f
appl ic a t ions
. (154
-1
GLOBAL TRENDS FOR RADIATION
PROCESSING OF POLYMERIC MATERIALS
European a c t i v i t i e s i n r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s a r e m a i n l y concerned w i t h t h e development o f raw m a t e r i a l s and f i n i s h e d p r o d u c t s r a t h e r t h a n w i t h
investments
in i n d u s t r i a l p r o d u c t i o n equipment.
A t present there are approxi-
m a t e l y 800 t o 2,000 UV; 80 t o 100 EB and 1,000 t o 2,000 I R i n s t a l l a t i o n s e x i s t i n g
t h r o u g h o u t Europe; and i n 1990 t h e expected numbers are 4,200 UV, 210 EB and 4,200
I R r a d i a t i o n p r o c e s s i n g u n i t s r e s p e c t i v e l y . (134 ,155 ,156 1 C u r r e n t p r o j e c t e d e l ect r i c power c a p a c i t y r a t i n g s f o r t h e s e p r o c e s s i n g u n i t s i s between 500,000 and
1,500,000 kw. The p r e s e n t i n s t a l l a t i o n s a r e b e i n g used i n a wide v a r i e t y o f r e search, p i l o t and i n d u s t r i a l p r o d u c t i o n o p e r a t i o n s .
The l a r g e numbers o f e x i s t i n g
i n s t a l l a t i o n s i n many d i f f e r e n t f i e l d s of a p p l i c a t i o n s a l o n g w i t h t h e i n t e n s e
6-36
a c t i v i t i e s o f raw m a t e r i a l s u p p l i e r s and manufactures o f p r o d u c t s do n o t a l l o w f o r
a r e l i a b l e e s t i m a t i o n o f t h e use o f these r a d i a t i o n c u r a b l e m a t e r i a l s i n Europe.
The t o t a l 1978-1981 v a l u e o f r a d i a t i o n c u r a b l e m a t e r i a l s f o r Europe i s e s t i m a t e d t o
be between $300 t o $600 m i l l i o n and t h e v a l u e o f t h e s e m a t e r i a l s i n 1990 i s p r o j e c t e d t o be between $700 t o $950 m i l l i o n .
The c o a t i n g i n d u s t r y , p r e d o m i n a t e l y UV c u r a b l e c o a t i n g s , accounts f o r a p p r o x i m a t e l y
20 t o 30% o f t h e t o t a l r a d i a t i o n c u r a b l e p r o d u c t s consumed i n Europe.
--
__
The p r o d u c t
__l i n e s o r market share breakdown percentages f o r t h i s p a r t i c u l a r i n d u s t r y a r e as
f o l l ows :
UV c u r a b l e c o a t rigs
EB c u r a b l e c o a t
wood c o a t i n g s
metal d e c o r a t i o n and p r i n t i n g i n k s
paper and cardboard c o a t i n g s
f l e x i b l e p l a s t i c and f l o o r c o a t i n g s
o t h e r c o a t i n g systems
29
22
11
11
5
22
rigs
Total
li5rd-
I n Europe energy shortages do n o t appear t o be a major m o t i v a t i o n f o r c o n v e r t i n g t o
r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s over c o n v e n t i o n a l f o s s i l f u e l thermal c u r i n g
methods.
Europe has access t o crude o i l f r o m t h e M i d d l e East and A f r i c a , n a t u r a l
gas f r o m t h e Netherlands, S o v i e t Union and N o r t h A f r i c a .
The p r o d u c t i o n o f o i l and
gas f r o m t h e N o r t h Sea i s i n c r e a s i n g and c l a s s i c energy sources i n t h e f o r m o f h a r d
c o a l and l i g n i t e a r e n e a r l y w i t h o u t l i m i t a t i o n s .
The d r i v i n g f o r c e t h e n f o r prod-
u c t manufacture v i a r a d i a t i o n p r o c e s s i n g techniques c e n t e r s on p r o d u c t i o n e f f i c i e n c y , p r o d u c t performance and v a l u e added m a t e r i a l s . (157,158)
For example, r a d i a t i o n c u r a b l e c o a t i n g s on formed p a r t s has been i n p r o d u c t i o n
s i n c e 1981 i n a VW p l a n t i n Wolfsburg, Germany.
The p a r t i c u l a r c o a t e d p r o d u c t ( a
wheel r i m ) i s f i n i s h e d w i t h an e l e c t r o n beam c u r i n g u n i t (200 KV, 40 mA, 32
Mrad/sec, 400 mm wide) u s i n g a c o a t i n g having a r a d i a t i o n c u r e s e n s i t i v i t y o f 25
Mrad o r r a t e o f c u r i n g c a p a b i l i t y w i t h i n 0.8 sec.
These p r o d u c t s (9400 mm diam-
e t e r , 200 mm h e i g h t , 10 Kg w e i g h t ) can be coated and c u r e d a t a p r o d u c t i o n r a t e
of between 6 and 22 rims/min.
a t a c o s t savings o f about 67% over t h a t of a conven-
t i o n a l t h e r m a l l y c u r e d c o a t i n g system (Table 6-16).
(159)
-
F u t u r e a p p l i c a t i o n s f o r r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s i n Europe w i l l
be i n c o a t i n g s f o r automotive, metal and p l a s t i c products; t e x t i l e s , and adhesive
systems f o r a wide v a r i e t y o f s u b s t r a t e l a m i n a t i o n p r o d u c t c o n f i g u r a t i o n s .
6-37
Table 6-16
COST COMPARISON OF ELECTRON BEAM TO HOT AIR
CONVECTION CURING SYSTEMS FOR WHEEL RIMS (159)
Cost Factor
Application Quantity
Pai nted Surface/r im
Coating Cost
Overs pr ay
Coating Thickness
Hot Air Convection
Curinq Svstem
$/year
Percent of
Total
100 g r p 2
0.16 m
$2.45/1000 gr
30 percent
40 microns
19.95%
$119,950
EB Svstem
40 sr/f
0.16 m
$6.20/1000 gr
30 percent
40 microns
$/year
Percent of
Total
30.28%
$121,420
Labor Reauirements
20.94%
$125,820
19.75%
$79,200
Utilities
Natural gas
(1000 BTU/cft) cost
Start-up loss
Nitrogen
cost
Electric Energy
cost
Start - u p/S h u tdown Lo s s
1,480,000 Kcal/h
$5.5/1000 cft
8 percent
--
12.26%
$73,730
--
3.02%
$18,180
1.60%
$6,430
$720,000
4 years
11 %/year
37.15%
$223,300
200 kV, 60 mA
400 mm width
$580,000
4 years
11 %/year
44.85%
$179,870
462 m2
$87/m2
6.68 %
$40,190
72 m2
$87/m2
1.56%
$6,260
--
--
127 Kw/h
0.06 Kw/h
12 percent
EauiDment Investment
Cost with Start-up
Amortization time
Financing Costs
-15m3/h
$0. 28/m3
49 Kw/h
0.06 Kw/h
4 percent
2.20%
$8,820
Manufacturinq Area
Necessary Area
Cost o f Area/year
TOTAL COST/Y EAR
TOTAL COST/RIM
(2,142,000 rims/year)
$601,170
$0.281
6-38
$401,000
$0.188
I n Japan, r a d i a t i o n processing o f p o l y m e r i c m a t e r i a l s i s b e i n g used f o r wood,
m e t a l , paper, p l a s t i c and automotive c o a t i n g s and f o r i n k s .
E l e c t r o n i c and commun-
i c a t i o n i n d u s t r i e s i n Japan a r e a l s o h e a v i l y committed t o r a d i a t i o n p r o c e s s i n g
techniques i n a s i m i l a r manner as t h e i r U.S.
and European c o u n t e r p a r t s .
Japan i s
a l s o a major producer o f c r o s s l i n k e d w i r e , c a b l e and r u b b e r p r o d u c t s f o r t h e u t i l i t y , computer and automotive t i r e i n d u s t r i e s . (160,161)
A t t h e p r e s e n t t i m e i t i s e s t i m a t e d t h a t t h e r e a r e a p p r o x i m a t e l y 800 UV, 60-120 E6
___ __ . --
and 800 I R r a d i a t i o n processing u n i t s i n Japan.
The t o t a l number o f p r o c e s s i n g
u n i t s i s expected t o reach 2,500 (1,100 UV, 175 E6 and 1,225 I R ) i n 1990.
Current
and p r o j e c t e d e l e c t r i c power c a p a c i t y r a t i n g s f o r these p r o c e s s i n g u n i t s i s between
300,000 and 430,000
kw.
U l t r a v i o l e t and I R p r o c e s s i n g equipment i s m a i n l y used t o
f i n i s h i n k s and c o a t i n g s as p r e v i o u s l y d e s c r i b e d f o r Europe and t h e
U.S.
(134,162,163)
The c u r r e n t number o f e l e c t r o n beam p r o c e s s i n g u n i t s (60 u n i t s
i n 1982) a r e r a t e d a t an approximate t o t a l c a p a c i t y o f 2,400
kw and t h e d i f f e r e n t
a p p l i c a t i o n areas u t i l i z i n g t h i s technology are as f o l l o w s : (164)
0
0
0
0
0
0
0
Research and Development
Electric wire
P o l y e t h y l e n e foam
H e a t - s h r i n k a b l e sheet
and t u b i n g
Coatings
T i r e - r u b b e r sheet
Others
12 u n i t s (255 kw)
20 u n i t s (1,000 kw)
7 u n i t s (270 kw)
8 units
1 unit
6 units
6 units
(350 kw)
(50 kw)
(350 kw)
(125 kw)
An i n t e r e s t i n g a p p l i c a t i o n o f e l e c t r o n beam c u r e d p a i n t systems f o r metal c o i l
s t o c k i s d e s c r i b e d i n Reference 165.
I n t h i s p a r t i c u l a r a p p l i c a t i o n i t was f o u n d
t h a t t h e EB c u r e process and a s s o c i a t e d c o a t i n g m a t e r i a l s s i g n i f i c a n t l y o u t p e r formed a c o n v e n t i o n a l thermal c u r e c o a t i n g system ( T a b l e 6-17).
From these r e s u l t s
i t appears t h a t a t l e a s t one f a c t o r e f f e c t i n g t h e f u t u r e growth o f E6 c u r e proces-
s i n g t e c h n o l o g i e s i s t h e development o f new polymer and c o a t i n g m a t e r i a l s .
These
new c o a t i n g m a t e r i a l s w i l l have t h e c a p a b i l i t y t o produce h i g h q u a l i t y f i n i s h e s f o r
r e f r i g e r a t o r s , microwave ovens and a i r c o n d i t i o n e r housing f i x t u r e s .
A t t h e pres-
e n t t i m e , t h e r e a r e more than t e n Japanese p a i n t and r e s i n manufacturers who engage
i n t h e development o f EB-cured p a i n t s and r e s i n s .
6-39
Table 6-17
COMPARISON BETWEEN EB CURING AND THERMAL CURING COATING
SYSTEM ON ELECTROGALVANIZED STEEL (165)
E l e c t r o n Beam
Cured C o a t i n g
Thermal Cured
A c r y l ic
Thermal Cured
PV c
Gloss
85
80
45
S u r f ace hardness
(pencil 1
8H
F-4H
2H
1500 h r s
240-500 h r s
240-500 h r s
Stain resistance
Excel l e n t
Fair-poor
Fair-poor
Heat r e s i s t a n c e
Excel l e n t
Fair
Poor
E v a l u a t i o n Tests
--
S a l t spray
resistance
The e s t i m a t e d consumption values f o r r a d i a t i o n p r o c e s s i b l e m a t e r i a l s i n Japan i s
c u r r e n t l y between $100 and $400 m i l l i o n and c o u l d reach $800 m i l l i o n i n 1990.
The g l o b a l o r worldwide i n t e r e s t i n t h i s t e c h n o l o g y i s s t r o n g l y e v i d e n t f r o m t h e
F o u r t h I n t e r n a t i o n a l Meeting on R a d i a t i o n Processing h e l d i n Yugoslavia i n 1982
(1661,
which was attended b y r e p r e s e n t a t i v e s f r o m a t l e a s t 35 d i f f e r e n t c o u n t r i e s .
The r a p i d growth o f r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s has been w e l l documented i n t h e U n i t e d S t a t e s , Europe, and e s p e c i a l l y Japan.
Global i n t e r e s t i n
r a d i a t i o n p r o c e s s i n g r e s e a r c h and developments w i l l c o n t i n u e t o i n c r e a s e w e l l beyond t h e y e a r 1990.
6-40
Section 7
CONCLUSIONS, FUTURE DEVELOPMENTS AND TECHNICAL VOIDS
I n t h e l a s t 15 y e a r s t h e c o n v e r s i o n o f e l e c t r i c a l energy i n t o i n f r a r e d , u l t r a v i o l e t
___
__.
and h i g h energy e l e c t r o n e l e c t r o m a g n e t i c r a d i a t i o n has gained worldwide acceptance
as an e f f i c i e n t and economical method f o r m o d i f y i n g p o l y m e r i c m a t e r i a l s .
These
r a d i a t i o n m o d i f i e d polymer systems a r e a s s o c i a t e d w i t h many d i f f e r e n t types o f
p r o d u c t s which a r e produced under a wide d i v e r s i t y o f m a n u f a c t u r i n g o p e r a t i o n s .
From a consumer p o i n t o f view, almost e v e r y day we encounter a p o l y m e r i c p r o d u c t
t h a t has been manufactured o r processed by some f o r m o f r a d i a t i o n energy:
0
Wood f u r n i t u r e ( I R o r UV c u r a b l e c o a t i n g s )
0
Beer/beverage can l a b e l s ( I R o r UV c u r a b l e i n k s )
0
Metal p i p e c o a t i n g s (UV c u r a b l e c o a t i n g s )
0
Packaging (paper, f o i l
0
F l o o r c o a t i n g s (UV c u r a b l e c o a t i n g s )
0
Printed publications (IR/UV curable inks)
0
Graphic screen p r i n t i n g i n k a p p l i c a t i o n on m i r r o r s (UV c u r a b l e
inks)
0
Foamed p l a s t i c i n s u l a t i o n (EB i r r a d i a t e d p l a s t i c s )
,film)
(UV/EB i n k s and c o a t i n g s )
Adhesive tapes (EB c u r e d adhesives)
0
Rubber t i r e s (EB i r r a d i a t e d r u b b e r )
0
Food packaging (EB i r r a d i a t e d p o l y o l e f i n s )
0
Wire (EB i r r a d i a t e d p o l y o l e f i n s )
@
Telephone c a b l e / o p t i c a l f i b e r s (UV c u r a b l e c o a t i n g s )
@
Computers (UV/EB polymer r e s i s t m a t e r i a l s 1
0
Recording t a p e (EB c u r a b l e c o a t i n g s )
I n t h e U n i t e d S t a t e s i t i s e s t i m a t e d t h a t t h e t o t a l use o f r a d i a t i o n p r o c e s s i b l e
m a t e r i a l s i s v a l u e d a t a p p r o x i m a t e l y $0.7 t o $1.1 b i l l i o n and i s expected t o
7-1
i n c r e a s e t o between $1.4 and $1.8 b i l l i o n i n 1990.
Currently there are
a p p r o x i m a t e l y 3035 t o t a l r a d i a t i o n (UV, EB, I R ) p r o c e s s i n g u n i t s i n t h e U n i t e d
S t a t e s which are r a t e d a t a t o t a l ( c u m u l a t i v e ) c a p a c i t y o f 430,000 kw.
I n 1990 t h e
t o t a l number o f p r o c e s s i n g u n i t s i s expected t o reach 8610 u n i t s f o r a t o t a l r a t e d
c a p a c i t y o f 1,500,000
kw.
European and Japanese e s t i m a t e s f o r r a d i a t i o n
p r o c e s s i b l e m a t e r i a l s a r e valued a t a p p r o x i m a t e l y $0.3 t o $0.6 and $0.1
b i l l i o n respectively.
o $0.4
These values should i n c r e a s e t o $0.7 t o $0.95 b i l ion
(Europe) and $0.8 b i l l i o n (Japan) i n t h e year 1990.
The t o t a l number o f r a d i a t on
p r o c e s s i n g u n i t s f o r Europe i s a p p r o x i m a t e l y 2990 u n i t s (500,000 kw t o t a
-_
.
.
._
.
.-
capac t Y
r a t i n g ) and a p p r o x i m a t e l y 1690 u n i t s (300,000 kw t o t a l c a p a c i t y r a t i n g ) a r e
c u r r e n t l y i n s t a l l e d i n Japan.
i n c r e a s e t o 8610 (1,500,000
I n t h e year 1990 t h e number o f u n i t s i s expected t o
kw c a p a c i t y r a t i n g ) and 2500 (430,000
kw t o t a l c a p a c i t y
r a t i n g ) f o r Europe and Japan r e s p e c t i v e l y .
The g l o b a l commercial success o f r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s i n
many d i v e r s e a p p l i c a t i o n areas can be a t t r i b u t e d t o t h e f o l l o w i n g f a c t o r s :
Value added p r o d u c t ( r a d i a t i o n c u r a b l e polymer t e c h n o l o g i e s can
m o d i f y low c o s t and low q u a l i t y s u b s t r a t e m a t e r i a l s i n t o h i g h
performance p r o d u c t s ) .
Higher q u a l i t y p r o d u c t ( b e t t e r d u r a b i 1it y o r g r e a t e r p e r f o r m ance c a p a b i l i t i e s ) .
High speed manufacture/low scrap
oss.
Product cannot be manufactured by any o t h e r method ( h e a t s e n s i t i v e s u b s t r a t e and p r o d u c t s assoc a t e d w i t h t h e m i c r o e l e c t r o n i c s i n d u s t r i e s 1.
EPA p o l l u t i o n requirements.
E l i m i n a t i o n o f s o l v e n t applied/removal c o a t i n g systems (reduct i o n i n m a t e r i a l i n v e n t o r y , r e d u c t i o n i n f i r e hazards and e l i m i n a t i o n o f concerns about t h e a v a i l a b i l i t y o f s o l v e n t s ) .
Reduction i n energy c o s t s .
The t o t a l impact o f r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s , w h i l e s i g n i f i c a n t ,
i s s t i l l a m i n o r p a r t o f t h e t o t a l p r o d u c t m a n u f a c t u r i n g techniques c u r r e n t l y i n
use today.
The o v e r a l l annual growth r a t e f o r r a d i a t i o n p r o c e s s i n g techniques i s
p r o j e c t e d t o be between 10 t o 20%, t h u s i t i s an a t t r a c t i v e area f o r f u t u r e
7-2
r e s e a r c h and development a c t i v i t y .
Several f u t u r e developments expected f o r t h i s
t e c h n o l o g y can be d e s c r i b e d as f o l l o w s :
__
0
Continued r e s e a r c h i n h i g h energy p h y s i c s d i r e c t e d a t e l e c t r o n
beam a c c e l e r a t o r s f o r beam propagation, maintenance and
control.
0
Continued r e s e a r c h and development i n UV and I R p r o c e s s i n g
equipment.
0
Development o f new r a d i a t i o n s e n s i t i v e p o l y m e r i c m a t e r i a l s .
0
Development o f new speci a1 t y p r o d u c t s and markets f o r r a d i a t i o n
processing technologies.
0
Reduction i n m a t e r i a l c o s t s ( l o w e r c o a t i n g c o s t s ) t o t h e u s e r
o r product f i n i s h e r .
A t t h e p r e s e n t time, most o f t h e e x i s t i n g r a d i a t i o n p r o c e s s i n g equipment i s capable
of meeting t h e demands o f c u r r e n t p r o d u c t p r o c e s s i n g o p e r a t i o n s .
The major t e c h -
n i c a l v o i d s t o be addressed i n t h e f u t u r e a r e i n t h e areas o f new m a t e r i a l s d e v e l opment and s c i e n t i f i c u n d e r s t a n d i n g ' o f t h e complex p h y s i c a l and chemical f a c t o r s
a s s o c i a t e d w i t h polymer network f o r m a t i o n , c o a t i n g - s u b s t r a t e adhesion phenomena and
t h e d u r a b i l i t y o f r a d i a t i o n processed p o l y m e r i c m a t e r i a l s under l o n g - t e r m m u l t i p l e
s t r e s s environments.
S p e c i f i c f u t u r e r e s e a r c h goals f o r t h i s t e c h n o l o g y can be
d e s c r i b e d as f o l 1ows :
0
Development o f new n o n t o x i c , low v i s c o s i t y , 100% r e a c t i v e monomer and o l i g o m e r m a t e r i a l s f o r use i n r a d i a t i o n c u r a b l e c o a t i n g
systems
.
0
Development o f new adhesion promotion monomer , o l igomer and
p o l y m e r i c m a t e r i a l s f o r use i n r a d i a t i o n c u r a b l e c o a t i n g systems a p p l i e d t o metal s u b s t r a t e s .
0
Development o f new r e s i s t m a t e r i a l s f o r e l e c t r o n i c and o p t r o n i c
applications.
0
Long t e r m aging s t u d i e s o f r a d i a t i o n processed polymers and
c o a t i n g s i n o r d e r t o e s t a b l i s h a r e a l i s t i c expected s e r v i c e
l i f e projection capability.
The p r e s e n t b e n e f i t s f r o m r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c m a t e r i a l s a r e d e r i v e d
f r o m improved q u a l i t y , s p e c i a l p r o p e r t i e s and h i g h e r p r o d u c t i v i t y .
The advantages
o f low-energy consumption and l o w p o l l u t i o n a r e g e n e r a l l y secondary c o n s i d e r a t i o n s
b u t t h i s c o u l d change d r a m a t i c a l l y depending on EPA r u l i n g s and a v a i l a b i l i t y o f
f o s s i l f u e l supplies.
Increased usage o f r a d i a t i o n p r o c e s s i n g o f p o l y m e r i c systems
w i l l depend on m a t e r i a l c o s t s and addressing t h e t e c h n i c a l v o i d s discussed above,
7-3
as w e l l as, t h e e f f e c t s o f competing t e c h n o l o g i e s w i t h i n s p e c i f i c market areas.
However, t h e r a p i d cure, low processing temperatures, and development o f s p e c i a1 t y
p r o d u c t s w i l l i n s u r e t h a t r a d i a t i o n p r o c e s s i n g t e c h n o l o g i e s w i l l c o n t i n u e t o grow
i n importance t h r o u g h o u t t h e world.
7-4
Section 8
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______
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8-8
Appendix A
MANUFACTURERS OF RADIATION PROCESSING EQUIPMENT AND MATERIAL SUPPLIERS
INFRARED SYSTEMS
PHOTOINITIATORS
Soneko, Inc.
87 E l i z a b e t h Avenue
Somerset, NJ 08873
(201 ) 873-2217
Aceto Chemical Co., Inc.
126-02 Northern Boulevard
Flushing, NY 11368
( 718 1 898-2300
ULTRAVIOLET SYSTEMS
Ciba-Geigy Corporation
3 S k y l i n e Drive
Hawthorne, NY 10532
(914) 347-4700
Canrad-Hanovia, Inc.
100 Chestnut S t r e e t
Newark, NJ 07105
(201) 589-4300 ~ 2 0 8
MONOMERS
Fusion UV Curing Systems
D i v i s i o n of Fusion Systems Corporation
7600 Standish Place
R o c k v i l l e , MD 20855
(301 ) 251-0300
ARCO S p e c i a l t y Chemicals
D i v i s i o n o f ARCO Chemical Company
Westtown Road a t W. Chester Pike
West Chester, PA 19380
(215) 692-8400
Union Carbide Corporati on
Linde D i v i s i o n
5705 W. Minnesota
Indianapolis, I N 46421
( 317) 214-1200
Cel anese Chemical Company
1250 W. Mockingbird
Dallas, TX 75247
(214) 689-4000
Diamond Shamrock Chemicals /Co.
D i v i s i o n o f Diamond Shamrock Corp.
350 M t . Kemble Avenue
Morristown, NJ 07960-1931
(201) 267-1000
HIGH ENERGY ELECTRON SYSTEMS
Energy Sciences I n t e r n a t i o n a l
D iv is i on of Energy Sci ences Incorporated
109, Rue de Lyon
1211 Geneva 13
Switzerland
22 45 -88- 21
Morton Chemical
D i v i s i o n of Morton Thiokol, Inc.
101 Carnegie Center
Princeton, NJ 08540
( 609) 396-4001
-
RPC I n d u s t r i e s
3210 Investment Boulevard
Hayward, CA 94545
(415 785-8040
A-1
~
_
_
~
OLIGOMERS
POLYMERS
ARCO S p e c i a l t y Chemicals
D i v i s i o n o f ARCO Chemical Company
Westtown Road a t W. Chester P i k e
West Chester, PA 19380
(215 ) 692-8400
ARCO S p e c i a l t y Chemicals
D i v i s i o n of ARCO Chemical Company
Westtown Road a t W. Chester P i k e
West Chester, PAa 19380
(215 ) 692-8400
Diamond Shamrock Chemicals Co.
D iv i s i on o f D i amond Shamrock Corpor a t ion
350 M t . Kemble Avenue
Morristown, NJ 07960-1931
(201) 267-1000
Cel anese Chemical Company
1250 W. M o c k i n g b i r d
D a l l a s , TXx 75247
(214) 689-4000
_
Lord Corporation
I ndus tr ia1 C o a t i ngs D iv is ion
2000 West Grandvi ew Boulevard
E r i e , PAa 16514
(814 ) 868-3611
Lord Corporation
I n d u s t r i a l Coating D i v i s i o n
2000 West Grandview Boulevard
E r i e , PA 16514
(814) 868-3611
Morton Chemical
D i v i s i o n o f Morton T h i o k o l , I n c .
1 0 1 Carnegie Center
P r i n c e t o n , N J 08540
(609 ) 396-4001
Morton Chemical
D i v i s i o n o f Morton T h i o k o l , I n c .
1 0 1 Carnegie Center
P r i n c e t o n , NJ 08540
(609) 396-4001
A-2