Letting Bonds Flex Their Muscles
Aside from elasticity, an adhesive must possess tensile strength in everyday applications. The adhesive layer may become damaged in service due to local overloading, whether because of the conditions under which it is used or because a jagged object acts on it from the outside. If the adhesive has inadequate tear resistance, the small damaged area may rip open during the next loading cycle.
A liquid waterproofing system based on GENIOSIL® XT 50, as being tested here at a WACKER lab in Burghausen, can be used to protect outdoor tiles against moisture and frost.
No matter how they arise, dynamic loads continually generate fluctuating mechanical stresses in the adhesive layer. An elastic adhesive layer moves with the adherends. It spreads the stress across the bonded area, dissipating local stress peaks.
Polyurethane-based adhesives have traditionally been the materials of choice for bonds exposed to highly dynamic stresses; for waterproofing membranes, formulations made with polymethyl methacrylate have also commonly been used. That could now change. “Our silane-modified polymers in the new GENIOSIL® XT product series can be formulated so that the mechanical properties of the cured end products match those of standard adhesives and sealants,” explains Lidia Miszke, Business Development Manager at WACKER SILICONES.
Products formulated with GENIOSIL® XT have a broader adhesion spectrum than polyurethane-based systems.Lidia Miszke Marketing Manager, Construction Sealants & Adhesives
Firm, Extensible and Tear-Resistant
This new product series is based on silane-terminated polyethers. Like typical silanes, the products crosslink and cure upon contact with atmospheric moisture. “The new polymers have been optimized so as to have a low viscosity on the one hand and a high number of silyl groups per unit volume on the other,” explains Dr. Lars Zander, in charge of developing GENIOSIL® XT in WACKER’s Application Technology department in Burghausen. “Consequently, the new polymers build up a solid, yet elastic network as they cure.” He added that the corollary was that adhesive layers and waterproofing membranes based on the new polymers possessed a high internal strength, yet were highly extensible and tear resistant.
Versatile Range of Formulations
The new polymers are extremely versatile when it comes to formulation options. This versatility stems not only from their low viscosity, but also from their compatibility with all other GENIOSIL® silane-modified polymers, with which they can be blended in any proportion to adjust the properties of the binder system to the application.
Automotive & Transport Coatings & Paints Food Life Science Energy Elastomers & Plastics Health Electrics & Electronics Construction Sustainability Distribution Composites Textiles, Leather & Nonwovens Paper, Films & NIP Adhesives & Sealants