Document 6502371

"Green" Textiles
How to Meet the Requirements for Eco-Textiles
By Ulrich Sewekow, Bayer AG, Leverkusen, Germany
S
ome years ago reports appeared in
journals and on television, especially in Germany, about a supposed
harmful potential of clothing to buman
health. Some real cases were reported;
ABSTRACT
A few years ago reports appeared in
European media concerning alleged
health hazards with clothing. Textile
finishers, textile producers and
related associations as well as
research and testing institutes took
this as a good opportunity for a new
market segment and created socalled eco-textiles. They are specially
labeled as toxicologically tested.
Aside from trademarks of single
companies; e.g., eco line, green
cotton, natural line etc., the most
iinportant standards in Europe are
Öko-Tex Standard 100 and M.S.T.
According to the requirements the
goods are controlled for pH, some
fastness properties, formaldehyde,
carcinogenic dyes, dyes that can
break down into carcinogenic
arylamines or can cause allergic
reactions to the skin, extractable
harmful heavy metals, halogenated
carriers or contaminations with
pentachlorophenol and pesticides.
The requirements of labelling and
if they can be met with normal raw
materials (fibers, dyestuffs and
chemicals) or if a special selection
must be made are reviewed. The
experience with textiles to be tested
for labeling shows that most of the
problems arise in the field of heavy
metal complex dyes which could be
extracted from the fabrics by
perspiration or saliva solutions. It can
not be shown that in all cases
dyeings with metal complex dyes in
heavy shades meet the requirements,
so a special selection is sometimes
advisable. Models and recent
developments for an environmentally
friendly production are also reviewed.
KEY TERMS
Dyes
Eco-Textiles
Metal Complex Dyes
Öko-Tex Standard 100
January 1996 (XO
e.g., skin irritations from easy-care
treated fabrics containing an excess of
formaldehyde, and the case of a salesperson with lindane in her blood
which was supposed to be due to a
contamination of textiles. Additionally
journalists warned of a risk from carcinogenic dyes or those which can
break down into carcinogenic arylamines by enzymatic reduction (e.g.,
benzidine. or related compounds) or in
general by textile chemicals which
have not heen toxicologically evaluated. Some ofthe criticisms, suspicions
and accusations directed against conventional textiles include:
• Disease Through the Wardrobe, a
book
• Sensitizing [allergic effects) from azo
dyes, formaldehyde, optical brighteners, and softeners
• Poisonous—toxic residues of pesticides and preserving agents on cotton and wool
• Synthetic dyes
• Cancer induced by azo dyes, monomer residues in manmade fibers,
formaldehyde, and halogenated carriers
• Use of pesticides in cotton farming
such as DDT, Lindane and hexachlorocyclohexane
• Use of artificial fertilizers in cotton
farming
• Preservation agents in cotton and
wool such as pentachlorophenol
• High energy and water consumption
during processing
• Effluent pollution through dyeing
and finishing including dyes, preparation, size, phosphate, bleach,
heavy metals and complexing agents
• Insufficient protection of workforce
from dust and noise during processing
Though no real disease could be
detected in most of these cases, consumers, consumer associations, authorities and last but not least textile
producers were alarmed. It was not
seen hy the uninformed public that the
reports were exaggerated or false. On
the other hand some people convinced
of a heavy impact of the textile treatment processes on the environment,
wanted to act more environmentally
responsible. Up to that point, textiles
were considered by the majority of the
consumers as entirely safe from the
health point of view. There were no
fears of health risks from wearing
clothing. They were chosen on the
basis of purpose, functionality and
fashion. Today some consumers and
textile producers are uncertain and
doubtful about the safety of garments
from a health point of view. As a result, it was not surprising that textile
companies began to offer textiles
which were advertised to be produced
in an environmentally friendly manner
and/or safe to wear. Large department
stores chains and mail order houses responded to this advertisement campaign and began to offer such textiles,
in a word "green products."
"Green Garments" • The Beginning
What are "Green Garments?" At the
beginning of the late eighties no clear
definition existed, which meant the
term was open to interpretation. To
expound the actual or putative advantages of biological, ecological, natural
or similarly described clothing, they
advertised with slogans showing
clearly what the trade understands by
bio textiles, and how the environment
and the consumer would be protected.
Some ofthe slogans are:
• Unexcelled natural product
• For demanding environmentalists
• A fahric which protects our future
• 100% natural fiber
• Hand-picked cotton
• Cotton grown without pesticides and
artificial fertilizers
• Pollution-free dyed
• Dyed with biodegradable dyes
• Not azo-dyed
• Rinsed with crystal clear water
• Mechanically stabilized—formaldehyde free
• Bio-stonewashed (stones and water
only)
• Without chemical dyes and additives
The substance of these advertisements
is very small, and is frequently untenable in terms of fair competition. How
is the consumer to know why the natural product is unexcelled or more enTextile Ctiemist and Colorist
21
vironmentally friendly, and how he is
protecting the environment by purchasing this product? The expression
"100% natural fiber" of course makes
it clear that only cotton, wool, silk,
linen etc. were used as fiber materials.
Also clear is the claim "no agents used
containing formaldehyde." Uncertainties arise for the specialist when he
looks critically at the other slogans;
e.g., "pollution-free dyed" in case of
textiles dyed with reactive dyes or pigments. Who knows of a dyeing process
without residual matter to be disposed
of as waste? Which textile finishers do
not rinse with "crystal clear water?"
Here self-evidence is being featured as
an advantage for the consumer. A considerable proportion of the slogans
mentioned can be put unceremoniously in the "advertising" drawer, especially since concepts with the prefixes "natural", "bio", "eco" etc. were
not precisely defined at that time. Advertising measures linked with environment protection are especially suitable in appealing to human emotions
and should therefore be judged in accordance with strict standards in regard to their objectivity and truth content. One cannot escape the impression
that many companies intend to improve the marketing of their products
or obtain higher prices with the aid of
the "eco-wave," as was clearly stated
in a mail order house catalogue—
"These advantages are well worth a
little extra."
Today's Eco-Textiles
In the meantime the situation appears
a little clearer. A multitude of ecobrands exist including:
• Öko-Tex Standard 100
• M.S.T. trademark of textiles tested
for harmful substances
• GuT environmentally friendly carpet
association
• Eco-Tex
• Natural Textiles
• Green Cotton
• Cotton 2000
• Öko-Cotton, Öko-Einish
• Green-line
• Nino-Life
• Haute Nature Collection
• Oko-Denim
Depending on the standpoint of their
maker the requirements of these brands
can be very different, very simple like
"natural fibers," "no chlorine bleach"
or "formaldehyde-free" or more complex because they were produced
under advanced environmentally
friendly conditions or tested for harmful chemicals.
The most important eco-Iabel for
textiles in Germany and, in my opinion, in Europe is Öko-Tex Standard
22
Textile Chemist and Colorist
100. It was launched in 1986 by the
Austrian Textile Institute, Vienna as
ÖTN 100. In 1990 an association was
formed involving the well-known German Textile Research Institute in
Hohenstein and the International Eederation for Research and Testing on the
Field of Textile Ecology. Today the association consists of 13 institutes in 13
European countries. Another label
which seemed to become also important
was
M.S.T.
(Markenzeichen
schadstoffgeprüfter Textilien, which
can be translated as trademark for textiles tested for harmful substances). It
was introduced by the Federation for
Consumer and Environmentally
Friendly Textiles founded by German
textile associations, dyehouses and garment producers. Its requirements were
very close to the above mentioned. In
order not to confuse consumers with a
multitude of different eco-lahels, both
merged in September 1994 under the
name of Öko-Tex Standard 100.
Öko-Tex Standard 100
This label is bestowed to textiles meeting the specific requirements shovra. in
Table I. They are not indefinitely fixed.
The parameters and the limits can be
changed according to new scientific
knowledge. Today's requirements are
discussed below.
pH-Value
The pH-value which is determined
according to ISO 3071, is restricted to
4.8-7.5, and 4,0-7,5 for wool and silk
respectively, because this range corresponds to the natural conditions of
undamaged human skin. It is not difficult to achieve it through final acidification of treated fabrics or sufficient
rinsing.
rasine5s
Fastness properties seem not to be a
toxicological factor. The background
for their presence in the specifications
is that dyes which are permanently
fixed on the fibers cannot migrate onto
the skin and cause harm. Therefore a
certain level of wetfastness is required—namely to water, crocking,
perspiration and saliva according to
the corresponding DIN or ISO Standards 105. The saliva fastness (DIN
63160) is required for baby wear because babies usually suck on their
clothing but do not perspire. Though
the stipulated fastness levels are not
too high, a special selection of suitable
dye ranges must be made. It is not problematical to meet them on cotton with
reactive dyes if they are properly fixed
and rinsed, but direct dyes can cause
problems due to their lower wetfastness levels. Generally speaking,
direct dyes in heavy shades aftertreated
with a cationic fixing agent do not meet
the required level and this is sometimes also the case in medium-color
depths depending on the type of dye
used. In light shades the fastness levels can he easily achieved. Wool dyed
with fast milling, premetallized or
afterchroming dyes, and polyester,
polyamide and polyacrylics fibers do
not seem to be a problem. The consequence is that the quality of textiles
certified to this or related standards is
improved because dyes with sufficient
fastness properties have to be used and
rinsing processes have to be carried out
accurately. In this sense the sale of a
silk blouse dyed with a cationic dye
in a deep-purple shade and which
when w^orn stains the underwear and
also the skin would not meet eco-textile requirements.
Table 1. Specifications for Öko-Tex Standard 100
Parameter
pH value in extract
Fastness
saiiva (baby wear)
perspiration (acid, basic)
washing
water, severe
dry crocking
wet crocking
Heavy metals in extract (ppm)'
arsenic
cadmium
chromium, total
chromium, VI
cobalt
copper
lead
mercury
nickel
formaldehyde
(Japan Law 112)
Limit
4.8-7.5
4-0-7.5 silk, wool
resistant
3-4
3-4
3
4
2-3
0.2-1,0
0.1
1-0-2.0
not detectable
1.0-4.0
25.0-50.0 (150.0)
0-2-1.0
0-02
1.0-4,0
20/75/300
Parameter
•
Halogenated Carriers
Carcinogenic dyes.
dyes able to split into
carcinogenic amines
Sensitizing dyes
Pesticides (ppm)''
total contents
Aldrin
Dieldrin
2,4-D
2,4,5-T
DDT
HCH
Heptaohior
(epoxide)
Lindane
Toxaphen
Emission of volatile
substances
Strange odor
Limit
not detectable
not detectable
not detectable
0.5-1.0
0.1-0.2
0.1-0.2
0.1
0-05
0.5-1.0
0.25-0.5
0.25-0.5
0.5-1.0
0.5
limited for
indoor textiles
limited
^Lower values concern the limits for baby articles.
OX
Vol. 28, No.
Harmful Metals
The concentration of extractable harmful metals on the textile is limited, that
does not mean the total amount of metals on the fibers when dyed with metal
complex dyes, but rather the amount
of metals which can be extracted with
artificial saliva or perspiration solutions used in the corresponding fastness tests. The extractions are carried
out in a liquor to goods ratio of 20:1 at
40C for one hour, and the metal concentration is determined by means of
AAS. Because no extended experience
about the toxicological effects of these
metals on skin depending on their concentration was available, the drinking
water standards in EU (European
Union) were used as a model with the
idea if it is good enough for drinking
purposes it cannot be harmful to the
skin. These limits in mg/L (ppm) were
taken as the maximum values in the
extract and calculated with regard to
textiles as shown in Table L It is surprising that the value for the copper
content is much higher than for the
other metals. The reason is that no
limit for copper ions exists in drinking water than only a recommended
value of 3 ppm because copper pipes
in houses for tapwater can release copper ions under specific conditions—a
situation which is sometimes not technically possible to avoid.
Ofthe metals listed in Table I. cadmium, lead and mercury are very unlikely to be present on fiber materials
because in general compounds based
on these metals are not used in the textile industry—they should only be
present in traces as impurities. Arsenic
acid has been used in Texas and Oklahoma as a desiccant to prepare mature
cotton plants for harvesting by stripping and is normally removed during
bleaching and scouring in the textile
processing.''^ According to Gotton Inc.,
the use of arsenic acid has been
stopped for over two years, Ghromium,
cobalt, copper and nickel compounds
are common in textile processing as
metal complex dyes, fastness improvers (copper), oxidizing agents for sulfur and vat dyes, and for the afterchroming of mordant dyes on wool
(potassium dichromate). Therefore one
has to pay attention to this subject. It
is important to state that according to
Öko-Tex Standard 100 and similar
standards the use of metal complex
dyes is not prohibited contrary to some
"greener" textile producers which totally ban their use for their collections.
Abandoning metal-complex dyes results in a loss of some important shades
like turquoise or brilliant green which
use copper or nickel phthalocyanates,
wetfastness in dyeings of wool or
polyamide (no premetallized or
afterchroming dyes) and lightfastness
in case of violet, blue or navy reactive
and direct dyes (Fig. 1).
Coming back to the discussion of
the Öko-Tex Standard 100 the use of
metal complex dyes should be viewed
differently. As the metal is an integral
part of the dye molecule, its concentration in the extract corresponds to the
dye fastness and the discussion can be
continued under this aspect.
Reactive dyes on cotton are firmly
fixed on the fiber and can be extracted
only in traces. Fig. 2 shows the results
of the test with the Levafix dye range
containing copper or nickel as complexes. It can be shown that the stringent limit of 25 ppm for baby wear cannot generally he achieved if heavy
shades are used. In lower color depth
this may be possible, but this must be
tested from case to case. The limits for
LF blue scale notes
metal complex dyes •
metal free dyes •
7i
654-
#•
m
•••
• • •
»•
•>
•
• •
•
••
•
V
Mm
•
•
•
•
3-
•
Formaldehyde
•
21U
1
1
yellow orange red
1
violet
1
1
blue
Fig. 1. Levafix dyes, lightfastness in 1/12 standard depth.
January 1996 OCO
1
1
1
1
tur- green navy- brown black
quoise
blue
adult apparel and other textiles are 50
ppm, and 150 ppm for accessories. In
our opinion it is no problem to meet
them with the Levafix range even in
heavy shades. Metal-containing direct
dyes entail greater problems because
of their limited wetfastness, and it is
therefore evident that they cannot
achieve the specifications in all cases.
Fig. 3 shows the results of evaluations
with the metal-containing Sirius Supra
dye range dyed in one-quarter and onehalf standard depth and aftertreated
with 3% Levogen WRD. After extraction with perspiration solutions the
leachable copper concentrations ofthe
brighter shades had a sufficiently low
level suitable for adult apparel. It is
interesting that the copper values for
turquoise, gray and black dyeings are
well below the limits. Though an acid
saliva instead of an acid perspiration
solution is used for the extraction of
baby wear similar results can be assumed. The limit of 25 ppm can only
be met with a special choice of dyes;
e.g., turquoise dyes—consequently,
direct metal-complex dyes should be
carefully checked if they will be used
for baby articles with eco labels.
The premetallized Isolan range consists of chromium and to a lesser extent
cobalt containing dyes. Diamond dyes
are mordant dyes which are afterchromed with dichromate. Both dye
ranges show excellent fastness properties. Processes using exactly calculated
dichromate quantities in the formula
and special conditions result in minimization of chrom.ium in the waste'water; e.g., the Bayer dichromate/Glauher
salt process.-^ Both dye ranges used on
wool in standard depths achieve the
Öko-Tex Standard 100 specification for
adult clothing—these are 2 ppm total
chromium and 4 ppm cobalt. Hexavalent chromium is not detectable in
any case. OnJy traces of chromium are
leached from wool fahrics dyed with
mordant dyes by perspiration solutions
but to a greater extent by saliva solutions. In samples from practical ¡^-eings
up to 40 ppm chromium \vas found.
This is assumed to be due to the low
pH (about 2.5) of the saliva solution
which can extract chromium ions not
fixed firmly enough on the wool fibers.
1
Formaldehyde is a toxic chemical, a
skin irritant and sensitizer. Controversial animal inhalation tests with very
high concentrations have shown that
it is a nasal carcinogen to rats and mice.
It is restricted in consumer products
such as cosmetics and textiles by law
in some countries or by voluntary
specifications of textile producers.
Formaldehyde concentrations are
Textile Chemist and Colorist
23
limit baby wear
20 I
o
J
I
limits adult wear
40
60
80
L
I
Red Violet E-4B\J\
Blue E-GRN
Blue E-RA
Blue E-3GL^
Navy Blue E-4RA S
Navy Blue E-2R Z
Navy Blue E-RA
Turquoise Blue E-BA
Turquoise Blue E-G 133%
T-Í?
160
_)
aftertreated
^m no
Olive E-GLy\
Brill. Green E-5BA ;
copper ppm
limits nickel
14
20
24
Textile Chemist and Colorist
iiiKp
5
Pesticides
40
Fig. 2. Extractable copper and nickel from dyeings with Levafix dyes, 1/1 standard depth, extracted with acid perspiration solution.
tested in accordance to the test specification of the Japan Law 112. It differs from the other procedures like
AATCC 112. Shirley I and II or DIN
54260 in the hydrolyzing conditions
and the detection method. Therefore
the results ofthe different methods are
not totally comparable because the
"free" and the releasable formaldehyde
are detected. The lowest value, 20
ppm, which is considered to be the
detection limit of this test procedure
is required for baby wear, the medium
value, 75 ppm, is required for clothing
usually worn directly on the skin—e.g.,
underwear, shirts, blouses and stockings, and the highest value, 300 ppm,
is the limit for outerwear apparel. Floor
coverings and mattresses are also
tested in ventilated chambers. The
emission limit is 0.1 mg/m-'. Formaldehyde in textiles is mainly generated
by crosslinking agents used as durable
press treatments or in pigment printing inks and wetfastness improvers for
direct or reactive dyeings.
The high formaldehyde concentrations in the air of dyehouses that use
durable press reactants and on the
treated textiles are a thing of the past.
Through processing improvements
and new products, chemical suppliers
and the finishing industry have succeeded in permanently reducing the
formaldehyde concentration to tolerable levels. Today, textile auxiliaries
having no or a low formaldehyde content are available which can easily
achieve the previously mentioned limits. Progressive "green" producers
sometimes prohibit the use of formaldehyde-containing textile chemicals so
that durable press finishes with conventional agents are no longer possible
for special eco-textiles.
l e c i i v e mm
types such as trichlorobenzene and
dichlorotoluene are accused of being
toxic and harmful to the environment.
The term "not detectable" really means
that their use is restricted because
traces can be found in the fibers despite drying and fixation. Alternatives
are carriers based on aromatic carbonic
ficids and alkyl phthalimides with betlor toxicologie properties but higher
prices or, if possible, dyeings without
carriers under high pressure or through
continuous processes. In cases of aggressive "green" textiles, this subject
is not an issue because only natural fibers can be used.
Pentachlorophenol
Pentachlorophenol (Pep) may be used
as preserving agent for the cotton fiber
size and wool during storage or transportation. It is toxic, teratogenic and
carcinogenic in animal tests. According to Cerman regulations, the production and the use of Pep is banned, and
impurities in textiles and leather products are allowed up to 5 ppm. Because
eco standards should be better than
official regulations, the maximum level
was prescribed at one tenth, or 0.5
ppm. According to the present experience with textile testing this limit is
rarely exceeded.
Halogenated Carriers
Carriers are used as auxiliaries for dyeing of polyester fibers with disperse
dyes at atmospheric pressure and temperatures below lOOC. The highly ef-
iimit baby wear
Aside the high water consumption for
cotton growing which is between 7 m^
for one kg cotton in Israel and 29 m^
in Sudan, the use of artificial fertilizers, pesticides and herbicides are criticized. On the other hand if insects,
plant diseases and viruses as well as
weeds are not controlled, supplies and
quality of fibers are reduced. It was
estimated that banning agrochemicals
in the U.S. would cut production of
cotton by 73%.-^ It is a claim ofthe critics of conventional cotton farming that
the plants are treated up to 25 times
during the growing period and that
toxic substances remain in the fiber
after harvest, causing potential health
hazards. But ^vhat are the facts? It is
true that some 20% of the world consumption of pesticides is used for cotton cultivation because cotton is very
sensitive in intensive mono-crop farming and grows in zones with hot climate favoring the attack of pests. On
average the pesticides are applied two
to four and at most six to eight times
at some sites. This is less than the nor-
limits adult wear. _copper ppm
160
Red Violet RL
Vioiet F2BL
Rubine K-2BL
Blue FBGLN
Blue FGG
Blue FRR
Blue F5GL
BlueGRL
Turquoise Blue S-FBL
Turquoise GL
Grey K-CGL
Black L-V
Fig. 3. Extractabie copper and nickel trom dyeings with Sirius Supra dyes, extracted
perspiration solution.
OX
Vol.26.
Table II. Textile Dyes that Can Cause Cancer
According to Animal Tests
C.I. Generic
Name
C.I.
Number
Acid Dye
Acid Red 26
Acid Red 114
Acid Violet 49
Basic Yellow 2
Basic Red 9
Direct Blue 6
Direct Blue 14
Direct Blue 15
Direct Blue 53
Direct Brown 95
Direct Black 38
Disperse Blue 1
16155
16150
23635
42640
41000
42500
22610
23850
24400
23860
30145
30235
Chemical
Class
Azo
Azo
Azo
Triphenylmethane
Ketonimine
Tri phenyl methane
Azo
Azo
Azo
Azo
Azo
Azo
Anthraquinone
mal application of agrochemicals to
wine grapes, potatoes or some vegetables. It is in the growers' interest to
apply them as efficiently as possible,
because they are expensive. The application of pesticides and defoliants is
carried out only when the bolls are still
closed so that the substances only
come into contact with the leaves and
not with the fibers. Herbicides are used
before sowing so that in all cases a contamination with these substances is
unlikely. Therefore it is not surprising
that evaluations of raw cotton samples
from the whole world for the most important pesticides done by the Bremer
Cotton Exchange in Cermany—the biggest European importer of cotton—
showed no or only low levels of
contamination in the range of the detection level.^ The concentration was
1-10% ofthe limits established according to the German regulation for maximum limits of pesticides in foodstuff
which are the same in the Oko-Tex
Standard 100. If pesticides were to remain on the fibers they would be removed in the textile wet processing
through scouring, bleaching and washing procedures.
The pesticides mentioned in this
list are chlorinated substances. Their
use is restricted in most of the cotton
growing countries. Coutamination
with these products is therefore unlikely and can be only from pollution
caused hy formerly used products
which are persistent. Alternative active agents are pyrethroides, carbamates or organophosphorous compounds which are readily degradable.
A group of "natural textile" producers give limits for a total of 28 agents
and others demand naturally grown
cotton—that means plants grown
without application of pesticides and
synthetic fertilizers. Their crop is
some thousand metric tons at present,
compared to 20 million tons of conventional cotton.
January 1996 CCO
Existing Textile
Textile Dye
no
yes
yes
yes
no
no
yes
yes
no
yes
yes
yes
yes
Table III. Arylamines Used as Dye Intermediates Causing
Cancer to Humans and to Animals
4-Aminodiphenyl, CAS No. 92-67-1
Benzidine, CAS No. 92-87-5
4-Chloro-o-loluidine, CAS No. 95-69-2
2-Naphthylamine, CAS No. 91-59-8
NA2 o-Amino-azobenzene, CAS No. 60-9-3^
o-Amino-azotoluene. CAS No, 97-56-3
o-Anisidine, CAS No, 90-4-0^
2-Amino-4-nitro-toluene, CAS No. 99-55-8
p-Chloroaniline, CAS No. 106-47-8
p-Cresidine. CAS No. 120-71-8
2,4-Diaminoanisol, CAS No. 615-05-4
4,4'-Diaminodipiienylmethane, CAS No. 101-77-9
3,3'-Dichlorobenzidine, CAS No. 91-94-1
3,3'-Dimethoxybenzidine (o-Dianisidine), CAS No. 119-90-4
3,3'-Dimethylbenzidine (o-Tolidine), CAS No. 119-93-7
3,3'-Dimethyl-4,4'-diaminodiphenylmelhane, CAS No. 101-77-9
4,4'-Methylene-bis-(2-chloroaniline), CAS No. •)01-14-4
4,4'-Oxydianiline, CAS No, 101-80-4
4,4'-Thiodianiline, CAS No. 139-65-1
o-Toluidine, CAS No. 95-53-1
2,4-ToluyIene-diamine, CAS No. 95-80-7
2,4,5-Tnmethylaniline, CAS No. 137-17-7
IIA1
^Not listed in the consumer goods ordinance.
Carcinogenic Dyes
The use of carcinogenic dyes and those
which degrade to carcinogenic arylamines under reductive conditions is
restricted. This demand is very common
in the German textile industry independent ofthe new eco standards. It is important to know that in nearly all countries no legal regulations existed in 1994
for the prohibition of their production,
import or use. Other exceptions are
Sweden and India banning dyes based
on benzidine.*" In the U.S. and the EU
the problem has heen intensively discussed between the authorities, ETAD
and the textile industry to prevent of
risk for workers and consumers.
Twelve dyes are known to be carcinogenic in animal tests, nine of them
are still used for textile dyeing though
they are of low importance according
to the Colour Index (Table II). •• The reason that these products were coming
under fire is the potential of azo dyes
to split into the arylamines from which
they were synthesized by chemical reduction (e.g., dye stripping) or enzymatic processes in the metaholism of
organisms. The most prominent examples are dyes based on benzidine
and congeners. The possibilities
arouses the suspicion that azo colorants which can release a carcinogenic
amine through reductive splitting, are
potentially carcinogenic too. The recommendation to treat the dyes in a
manner corresponding to that of the
related amines has been implemented
by legislation so far only in Germany.
Before the aforementioned ordinance
was enacted, there was not a legal ban
of their use, but some large textile companies voluntarily decided to refrain
from using them. The ordinance refers
to the German MAK-list (Threshold
Limited Value) where chemicals are
listed which are known to be carcinogenic to humans (MAK III Al), those
which are detected to be carcinogenic
in animal tests under conditions comparable to the workplace (MAK III A2)
and those which are under suspicion
to be carcinogenic (MAK III B). In most
cases dyes that can form MAK III Al
and III A2 products are restricted, but
rarely dyes forming III B arylamines.
Those which are still used today or
were formerly used for the production
of dyes are listed in Table III.
The manufacture of benzidine
based dyes was stopped in 1971 by
most producers. The reason was
mainly to protect production workers
from coming in contact with potentially bladder cancer-inducing benzidine. It can be seen from the Colour
Index that they are still produced by
some companies. The same is true for
dyes based on MAK III A2 amines.
German producers stopped making
them, but in some other countries that
is not the case. In all. about 28 acid, 81
direct, 8 disperse and 7 basic dyes are
listed in the Colour Index as e>;isting
commercial products. According to a
study commissioned by the U.S. consumer product safety commission
(CPSC), there is no risk to the wearer
from textiles dyed with benzidine congener dyes, as they do not penetrate tlie
skin." Though the exposure, combined
with an extremely minute skin penetration level, is very low for the consumer, in our opinion azo dyes which
can be reduced into carcinogenic
amines should not be used for textiles.
Substitution is not difficult because
alternatives are on tlie market. They are
however, sometimes more expensive.
In Cermany, the voluntary prohibition was overtaken by the second
amendment to the ordinance of conTextile Chemist and Colorist
25
sumer goods in July 1994—legally prohibiting the use of azo dyes capable of
releasing 20 mentioned carcinogenic
arylamines through reductive splitting
of azo bonds, as well as prohibiting the
import and trade of textiles dyed with
them. The 20 arylamines more or less
correspond to the MAK list (Table III).
According to the fourth amendment,
the deadline for manufacturing and
importing textiles containing these
dyes into Cermany is March 31, 1996
and for trade is September 1996. There
are exceptions with longer transitional
periods to 1998 and 1999 for pigment
printings, protective clothing and
clothing made from recycled fibers."^
According to the experience ofthe last
year it must be mentioned that many
problems have arisen because no unequivocal test method exists for the
detection ofthe dyes or arylamines.
Sensitizing Dyes
Recently, the use of sensitizing (allergenic) dyes was added to the requirements as a new parameter. These are
in most cases disperse dyes such as C.I.
Disperse Yellow 3, Disperse Orange 3,
Disperse Red 1 and 17, Disperse Blue
3, 106 and 124, as well as Naphtol AS.
Many of these are not only used for
dyeing of polyester but also for polyamide and triacetate where they can
easily migrate out of the fibers and
cause harm to tbe skin.
Ecologically Friendly Production
Up to now the majority of the statements involved human toxicological
aspects; i.e., the content of some hazardous substances in finished textiles,
but very little about process ecology.
To our best knowledge no standards
exist yet assessing textile production
under ecological aspects comparable to
Öko-Tex Standard 100. The association
which has launched this standard is
now discussing basic principles for
environmentally friendly production.
A model to compare and evaluate
environmental standards during production was developed in 1987 by the
Danish company Novotex for its
"Creen Cotton" apparel. In its brochure, the manufacturer states its view
regarding "green products," evaluating
the entire manufacturing process from
cultivation of cotton through spinning,
dyeing and finishing to disposal in
terms of environmental ratings. Alternative cultivation methods are being
sought, and hand picking of the cotton has already been put into effect,
with the use of defoliants and desiccants prohibited. The textiles are spun
and knitted on ultra-modern machinery which ensure that legal emission
limits—e.g., for cotton dust and noise
26
Textile Chemist and Colorist
are not exceeded. Dyeing is carried out^
in a modern dyehouse using West European dyes and full biological treatment of the effiuent. Clothing is mechanically finished; i.e., formaldehydefree. The seamstresses run no health
risk during processing, they work in a
pleasant atmosphere and are adequately paid—surely an allusion to
the manufacturing conditions in some
Asiatic low wage countries. We can be
sure that the exemplary conditions
described above also apply in the overwhelming majority of the U.S. and European textile mills.
But what really are environmentally
produced textiles? The concept has not
yet been clearly defined; i.e., it is open
to interpretation by the different companies. In the extreme case, it can mean
that the environment is in no way damaged during the entire life cycle ofthe
product. But no manufacturing process
can be carried out without the environment being subject to energy and raw
material consumption and waste emission. Also the stipulation that environmental pollution should be kept as low
as possible means nothing, as there is
no mandatory standard. Assessment is
easier, however, if the comparative
form "environment-friendlier" is used,
as reference can be made to an existing product or process. But here too,
data from polls represent a wide range
of opinions, from total abandonment
of all highly industrial production to a
situation where environment damage
should be as low as possible, but permitting products produced to the same
high standard. The first is represented
by the German Natural Textile Group,
an association of nearly two dozen
"green" textile companies setting specific, seemingly exaggerated quality
criteria for their products. For example.
the latest draft of their guidelines include the use of only natural fibers,
dyes and auxiliaries not containing
ethoxylates, free of heavy metals and
formaldehyde, organic halogenated
compounds, a special choice of surfactants, no optical whitening and no
treatments or finishes such as bleaching, mercerizing, mothproofing etc. All
dyes being used should have a lethal
toxicity LD50 of higher than 2000 mg/
kg and chemicals should not he classified as dangerous substances according to German Dangerous Substances
Regulation. Strictly speaking this
would also prohibit the use of common
chemicals like acids and bases because
of their corrosive properties. Though
the market share of the Natural Textile Group is insignificant, and their
apparel products represent a niche for
a specific consumer group purchasing
"alternative" products, their guidelines
standards.
Before joining the Öko-Tex Standard 100 the formally mentioned association launching M.S.T. also discussed a new label called M.U.T.,
which is translated to mean the trademark of environmentally friendly produced textiles. The discussion was at
the very beginning, but an agreement
existed to give requirements on the
field of water and air pollution, discharge of solid waste and restriction of
some chemicals during processing.
Standards have been set up hy the German government for emissions into
water and air. This means textiles from
abroad could he bestowed with this
label too, if effluents and waste air
streams are treated. The limits shown
in Table IV have to be achieved in the
effluent before discharging into surface
waters either by manufacturing facilities or by treatment plants of the community. They were taken from a draft
of a new regulation that was not yet
enacted concerning the discharge of
textile effluents. A well-operating mechanical/biological treatment plant is
the minimum standard to control
them. Chemicals which are prohibited
during processing include;
• Sodium hypochlorite used in
bleaching
• Alkylphenol ethoxylates used in
bleaching
• Potassium bichromate used as an
oxidizing agent
• Copper sulfate used for improving
fastness
• Chlorinated carriers
Chlorine is prohibited for bleaching
because of generating halogenated organic substances, of which some are
suspected to be carcinogenic; e.g.. chloroform.^^ In Germany hypochlorite
bleaching is no longer used for this reason. Alkylphenol ethoxylates are restricted because it was determined that
the degradatioji product with one or
two ethylene oxide residues are more
toxic than the original surfactant.
Table IV. Requirements for Ecologically
Friendly Production, Limits in Wastewater According to German Regulations
maienai
Limit, ppm
COD
BOO5
Nitrogen
Phosphorus
Hydrocarbons
Adsorbable organic halogens
Free Chlorine
Sulfide
Chromium VI
Chromium total
Copper
Nickel
Tin
Zinc
160
25
20
2
10
0.5
03
1.0
0.1
0.5
05
(.
O X Vol.26
Therefore a voluntary agreement hetween German manufacturers and the
government was signed in 1986 not to
sell them after 1989 on the Cerman
market for household and industrial
washing and cleaning purposes. Chromium and copper compounds as well
as chlorinated carriers which are suspected to be harmful should not he
used because of their low limits in effluents and their possibility to accumulate at the sewage sludge. Analyzing
only wet processing textile production
one can find further possibilities for
protecting the environment not only by
saving water, energy, dyes and chemicals, such as synthetic size and caustic soda, but hy secure storage to prevent emissions during an accident, by
use of biodegradable textile auxiliaries
and mineral oil-free pigment printing,
and last but not least by improvement
of working conditions; e.g., avoidance
of dust, soil and noise in the factory.
All the mentioned enterprises in this
field are private, none of them has an
official background. The official German
eco-label "Blue Angel" is awarded to
consumer products such as paint with
reduced solvent contents, paper products made of recycled materials or
sprays without ozone damaging agents
but not as yet to textiles. The European
Union has published a regulation on the
awarding of an EU eco-label to promote
the development, manufacture, marketing and use of products that have negligible effects on the environment.'-^ The
regulation defines an evaluation matrix
(Table V) which can be characterized as
a life cycle analysis from cradle to grave.
A Danish expert group is still developing the criteria for awarding the label
on the hasis of two textile examples,
namely cotton T-shirts and poly-cotton
bed linen. This work is at an early stage.
Table V. European Union Eco-Label Award Scheme
Area of the
Environment
Preliminary
Production Stage
Production
Distribution
& Packaging
Use
Disposal
Contribution
lo waste
Water
Pollution
Air pollution
Noise
Energy
consumption
Consumption
ot natural
resources
Effects on the
ecosystems
Conclusions
A multitude of activities through the
whole textile chain are taking place for
protecting the environment from damage by producing textiles or to humans
wearing them. But it is necessary that
the textile industry keep common
sense in mind and not withdraw from
technical competence and progressive
processes, as the discussion sometimes
showed. We are convinced that the
suppliers of dyes and chemicals and
the textile finishers will find the right
way in between the extremes.
Author's Address
Ulrich Sewekow, Bayer AG,
Geschäftsbereich Farben, Leverkusen
D-51368, Cermany.
References
1. Pi;rkins, Henry H. and Donald E. Brushwood,
Textile Chemist and Colorist, February 1991,
p26.
2. Perkins. Henry H. and Donald E. Brushwood,
Textile Chemist and Colorist. May 1993, p31.
3. Duffield, Peter A. and Karl Hoppen-Heinz,
Meiliand English. March 1987, p86.
4. Rhône-Poulenc, "Environmentai Issues and
Agricultural Impact. Technical Bulletin.
5. Anonymous, Cotton Report. 3/4, edited by
Bremer Baumwoü-börse, Breraen/Germany,
1993.
6. ETAD Annual Report, 1992,
7. Moll, Raul A.. A/e/y/ondE/igy/s/i, October 1991,
p836,
8. U.S. Consumer Product Safety Commission,
Final Recommendations on Benzidine Congener Dyes. 1983.
9. 2nd Ordinance for tbe Amendment of tbe Consumer Coods Ordinance fi-om 15.07.1994.
BGBl (Federal Law Gazette). Part t. 1994.
pl670.
10, 4thOrdinanceforthe Amendment of tbe Consumer Coods Ordinance from 20,07.1995,
BCBl (Federal Law Gazette), Part 1. p954,
11, Sebb. W.. Te.xtil Praxis International, August
1989, p841.
12, Council Regulation EEC 880/92 of 23.3.1992
Concerning a United System for the Awarding of an Eco-label. Official Journal of the EC
L99 of the European Communities. April 11,
1992,
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VISA, MASTERCARD and AMERICAN EXPRESS ACCEPTED
January 1996 CCO
7exi/7e Chemist and Colorist
27