WACKER will be showcasing a novel liquid silicone rubber for the heat-resistant coating of industrial textiles at Techtextil2007, taking place in Frankfurt from June 12 to 14. Even a very thin film of the new, solvent-free material is enough to produce an
Marketed as ELASTOSIL@ HT 10, WACKER's novel product is ideal for coating special-purpose textiles made of glass yarn or aramid yarn. Examples include yarns that must ensure reliable electrical insulation even when exposed to high temperatures
for a long time, as well as yarns that must withstand considerable folding and movement during use.
Only a thick film of conventional silicone product can confer good heat resistance. The novel liquid silicone rubber, in contrast, has a low viscosity and contains a highly effective heat stabilizer especially designed for thin-film coating.
Although just a thin film is applied to the textiles, they can endure temperatures some 20 to 30 °C higher than textiles with traditional silicone coatings. The coated fabric stays flexible even after two weeks' conditioning at 260 oCt and coated glass fiber fabrics do not become brittle. Another key characteristic of textiles coated with ELASTOSIL@ HT 10 is their ability to provide excellent electrical insulation. Even two weeks of continuous heat treatment at 260 °C causes just a slight drop in dielectric strength.
If textiles coated with ELASTOSIL@ HT 10 overheat or come into direct contact with flames, they do not release any toxic decomposition products. The textiles are flame retardant, thus complying with UL 94 VO requirements even after two weeks' conditioning at 260 °C.
The new coating material is solvent-free, can be pigmented in diverse ways and is easy to process. The good free-flow properties shown by WACKER's novel silicone make for low coating weights and firm anchorage of the coating to the substrate after curing. What is more, the low coating weights translate into substantial cost savings.
Coating glass fabric tubing with ELASTOSIL@ HT 10. The thin, liquid silicone film is then cured at about 150 ac. Glass and aramid yarns coated with ELASTOSIL@ HT 10 provide high heat resistance, good flexibility and excellent electrical insulation.
