The Munich-based WACKER Group has developed two new condensation-curing silicone rubber grades for textile coating: ELASTOSIL E 91 and ELASTOSIL E 92 N. Formulated without tin, these silicone grades meet the requirements of Öko-Tex Standard 100, an internationally recognized testing and certification system.
Both products can be processed using traditional methods. They adhere well to textile substrates and produce soft elastomers with notable non-slip properties. ELASTOSIL E 91 is designed to be processed in steam ovens, while ELASTOSIL E 92 N allows for quick processing at room temperature.
The new silicone rubber grades are acetic-curing systems. They vulcanize at room temperature under the influence of atmospheric moisture. The catalyst needed for curing is already incorporated in the formulation. ELASTOSIL E 91 and ELASTOSIL E 92 N use a newly developed catalyst system which does not contain organotin compounds. This makes both grades exceptionally user-friendly.
They also meet the organotin limits of the recent Öko-Tex Standard 100. Öko-Tex is a registered trademark of the International Association for Research and Testing in the Field of Textile Ecology, headquartered in Zürich, Switzerland.
ELASTOSIL E 91 and ELASTOSIL E 92 N are flowable products that are easy to process, allowing coaters to continue using their standard application and curing methods. The two silicone grades are also comparable to traditional silicones in terms of vulcanization rates. The viscosities of these products have been adjusted to thoroughly wet textile surfaces without penetrating the weave. Unlike ELASTOSIL E 91, ELASTOSIL E 92 N is exceptionally transparent and can be used with any fashionable color.
The two products differ by their catalyst system, which means that their processing characteristics are different as well. The catalyst used in ELASTOSIL E 91, for instance, can withstand higher processing temperatures.
Because ELASTOSIL E 91 forms a skin within a few minutes, it is ideal for processing in steam ovens. ELASTOSIL E 92 N, on the other hand, was optimized for rapid vulcanization of the rubber at room temperature. Typical applications of the new silicone grades include non-slip coatings of bands – such as those used in women's hosiery – and the rubber coatings of slip-resistant socks.
