Polycarbonate and polymethyl methacrylate (PMMA) are transparent thermoplastics. As lightweight and more robust alternatives to glass, they are used in construction, aircraft and the automotive industry, among other sectors. Carports, greenhouses or the interior paneling of airplanes and vehicles are often made of polycarbonate. PMMA, meanwhile, is used for aquariums, glazing in buildings or turn indicators and taillights in cars. Hobbyists also often use one of the materials when creating models.
Plastics require powerful adhesion promoters
“Materials such as PMMA or polycarbonate often need to withstand vibrations and temperature fluctuations without the bond releasing,” comments Dr. Thomas Schlosser, Technical Marketing Manager at Evonik Silanes. He advises Evonik’s customers to use silanes in adhesives and sealants. “In addition, they are exposed to weather influences and mechanical stress in many applications.” The problem here is that bonding the two materials is no easy matter. As a result, they pose significant challenges for the adhesives industry.
This is where VPS SIVO 260 and SIVO 280 come in: The two silane oligomers from Evonik’s Dynasylan® portfolio deliver a range of benefits as additives in adhesives and sealants, and they even work on substrates where other adhesion promoters struggle: Internal shear tests have revealed that VPS SIVO 260 improves adhesion on polycarbonate by up to 30 percent compared to common industry standards, while using VPS SIVO 280 more than doubles adhesive strength on PMMA. Moreover, these silanes decisively improve the mechanical properties of the end products, in turn significantly extending their service lives.
The two next-generation silanes not only display outstanding properties when used with plastics, however: They are also perfectly suited for adhesive formulations for use on metals. As a consequence, the two new products are in high demand for thermally conductive adhesives in the electromobility sector.
No adhesive labeling necessary
At the same time, VPS SIVO 260 and SIVO 280 make especially environmentally friendly formulations possible. “The two products consist of silane oligomers. This means that they release far fewer volatile organic substances, in this case methanol, when curing,” emphasizes Dr. Schlosser. This protects the environment and also allows the adhesives to be used indoors, for example. In addition, large quantities of silanes can be added to adhesives without the need for special labeling.
The low VOC content is a decisive factor in an age when sustainability and conservation of the environment are becoming ever more important. “VPS SIVO 260 and SIVO 280 give manufacturers chemically multifunctional and environmentally friendly silanes in a single product. And this considerably expands the range of applications,” adds a convinced Dr. Schlosser.