BORAX-FREE BONDING AT HERBSTER HÜLSEN

BORAX-FREE BONDING AT HERBSTER HÜLSEN
The use of borax and boracic acid in corrugated board and core board industries is
proving increasingly problematic for users of glue formulations on the basis of starch
products
In 2009 boracic acid, borax and borates were classified as CMR substances (cancerogene,
mutagene and toxic for reproduction substances) by the EU for chemical materials with the
30th ATP (Adaptation to Technical Progress). Strictly speaking, borax compounds which are
toxic for reproduction category two R 60 and R 61 have to be labeled with a skull. There was
a special European ruling that mixtures with less than 5,5% boracic acid do not require this
strict classification. Within the scope of REACH, however, on 20th June 2011 all boron
compounds were classified as SVHC substance (Substances of Very High Concern). This
resulted in a stricter classification and it is relevant from a content of 0,1%.
Boron Compounds to be banned from Product Portfolio
Consequently many companies in the chemical and processing industries have checked their
products in order to ban any boron compounds from their product portfolio and to take the
borax content in their sales products below the 0,1% limit.
Users, as for example the corrugated board and core board industry, add borax as an important
additive up to a proportion of over 20% to starch sizes for the control of rheology, stability
and adhesive properties. After the classification many manufacturers reduced the proportion
in their resin formula below 7% and accepted, out of necessity, a poorer performance of their
adhesive bonding.
They are also working with liquid suspensions of borax “borax solution” in order to avoid
high dust levels in the process. Thus the glue kitchen will continue to be a “poison laboratory”
because a substance on the SVHC list is still processed there. Since then there has been a
growing demand for safe substitutes from producers in the corrugated board industry of large
packaging manufacturers and customers, e.g. from the tissue industry which uses a large
quantity of cardboard tubes.
That there are different ways is shown by the company Herbster Hülsen in Schopfheim. This
company has thought for a long time about borax alternatives and in the first phase has looked
to cooperate with the Züricher Hochschule für Angewandte Wissenschaften (Zurich
University of Applied Sciences). This involves combining theoretical basics with practical
implementation. As a second step Herbster looked for suitable partners in the business world.
With Emsland-Stärke and BK Giulini they found two companies with whom they continue to
work within the scope of a joint project.
At the end of 2011 BK Giulini introduced the borax-free substitute Gilunal A. After intensive
research and development in the chemical properties the easily soluble aluminium component
Copyright ©2013 ICL Performance Products
was aligned to the effectiveness and utilization of borax in the capacity of a stabilizer.
According to CMR classification Gilunal A is harmless, meets the requirements of the 36th
recommendation of the BfR and can be applied to manufacturing papers, paperboards and
cardboards in contact with foodstuffs.
After intensive research Emsland-Stärke complemented this step with the development of
Emdex 1480 resulting in a dextrin based adhesive system. Initially different dextrins were
checked regarding compatibility and stability with Gilunal A. On the basis of these results
extensive studies were carried out at open times on adhesion velocities of various size
mixtures (see chart).
Specifically systems with high solid content (approx. 53%) were examined and their viscosity
was measured at various size temperatures. Measurements of open time/start bonding up to
complete bonding were then carried out at 20 C. On the basis of the results Emdex 1480 with
a proportion of 7% Gilunal A was favored for further application tests.
Field Trials
During the field trials at Herbster Hülsen in Schopfheim the formulation of EMDEX 1480,
Gilunal A and mineral fillers even proved superior in a technical and economical way
compared to the previous borax containing mixtures. Based on a borax proportion of 14% it
was possible to completely do without the additional borax. Only 7% of Gilunal A was
necessary to guarantee optimal adhesion of the cores. Starting tack, wet life and setting time
during fast drying perfectly fit the speedy production process and provide higher final strength
values. Furthermore in the mixture, additives of the Calgon and Lopon range (BK Giulini)
provide for optimal viscosity and a high proportion of solids of the dextrin size.
Herbster Hülsen considers the requirements of the adhesive to be met. For the bonding
process the ordinary requirements of adhesive properties, film hardness, thermal resistance as
well as increasingly environmental compatibility are playing an important role. Dextrins of
Emsland-Stärke are produced 100% from renewable resources. Dextrins are listed in
Appendix IV of the REACH Regulation and do therefore not require further registration.
They are also approved as additives for use in the food industry.
Dextrins
In the manufacturing of cores usually water glass, dispersion adhesives and increasingly
adhesives based on starch like Emdex 1480 are used. When using dextrin sizes the end
products distinguish themselves predominantly by high strength and dimension stability.
Furthermore, high solids concentration and short setting times of the sizes can be realized
with dextrins as could be shown here in the joint project. Due to the borax-free glue
formulation on the basis of Emdex 1480 and Gilunal A, Herbster Hülsen considers coming
closer to the goal of achieving more added value and more sustainability by using renewable
and harmless resources.
Copyright ©2013 ICL Performance Products
Specific Solutions for Borax-free Bonding
Gilunal A is a development of business unit APW – Al Compounds of BK Giulini,
Ludwigshafen. The unit is presently intensively working with partners from the starch
industry on specific solutions for borax-free bonding and application in the corrugated board
sector. The company is already represented at paper manufacturers via the unit BKG Paper
Solutions. Emdex 1480 is a newly developed dextrin from the company Emsland-Stärke,
Emlichheim. They have long-standing experience in the range of core manufacture.
Herbster Hülsen is a medium-sized, independent company in the paper and core production
sector. As a long-standing and reliable partner for the paper, film, foil, textile, label, selfadhesive tape and packaging industry the company has made a good name for itself through
solution competence and reliability in customer specific product development and
manufacturing processes.
Quote of the Month:
Zanders and M-real have never matched. This is like McDonalds having taken over the
restaurant of Castle Lerbach.
Frank Eschenauer, Works Council Chairman M-real, Zanders, Bergisch Gladbach, in an
interview with the Kölner Stadtanzeiger.
Copyright ©2013 ICL Performance Products