Letting Bonds Flex Their Muscles
Easy to Process
Thanks to their low viscosity, the new silane-modified GENIOSIL® XT 50 and GENIOSIL® XT 55 polymers can be processed easily and without the need for solvents. This gives them an advantage over many conventional binders. What is more, compounders can formulate the polymers with or without plasticizers and with or without fillers. Again, this adds considerable scope for tailoring the end product to the application, and offers a way to produce highly filled and hence cost-effective end products. Finally, adhesives and sealants formulated with the new polymers can be pigmented in any color, opening up new possibilities for designers.
“Products formulated with GENIOSIL® XT have a broader adhesion spectrum than polyurethane-based systems,” emphasizes WACKER manager Lidia Miszke. “The formulation will determine how they adhere to many common materials without the need for priming.” She went on to say that they were also less moisture-sensitive than polyurethanes, adding that GENIOSIL® XT products did not contain any free isocyanates and so could be formulated to adhesives and sealants that were not subject to labeling requirements.
No Tin Catalyst Needed
An alpha-silane-terminated polymer, GENIOSIL® XT 50 does not require an organo-tin catalyst for rapid curing. It is therefore suitable for producing tin-free industrial adhesives and crack-bridging waterproofing membranes. With GENIOSIL® XT 50, tensile strengths of up to about 9 N/mm² and tear strengths of up to about 50 N/mm (measured as per ASTM D 624 B-91) are feasible. The cured end product has such good mechanical properties that the nonwoven reinforcement traditionally required to seal flat roofs with liquid waterproofing systems can be dispensed with. Moreover, by eliminating fillers, compounders can produce highly transparent adhesives and seals.
“Our innovative silane-terminated polymers in the GENIOSIL® XT series are suitable for applications involving high dynamic loads.”Jürgen Herein Director of the Construction Sealants & Adhesives Business Team at WACKER SILICONES
GENIOSIL® XT 55 is a gamma-silane-terminated polyether for formulating strong structural industrial adhesives. Such adhesives need to be both highly elastic and extremely tear resistant. Laboratory tests performed with GENIOSIL® XT 55 yielded shear strengths of around 5 N/mm², combined with an elongation at break of around 700 percent and tear strengths of up to 16 N/mm (measured as per DIN ISO 34-1). These values are typical of window adhesives employed in the automotive industry.
“Our new silane-terminated polymers in the GENIOSIL® XT series are suitable for applications involving high dynamic loads,” says Jürgen Herein, head of the Construction Sealants & Adhesives business team at WACKER SILICONES. “They constitute a technically equivalent – in some respects even superior – alternative to established binder systems.”
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