Silicones/silicone rubber (VMQ)
Silicones/silicone rubber (VMQ) are a group of synthetic elastomers, which hold a special position due to their silicon-oxygen structure. This leads to a number of specific characteristics:
- Chemically stable
- Thermally resistant (mainly stable properties from -100 to 250 °C / -150 to 480 °F).
- Waterproof and water-repellent
- Separation effect towards many other materials
- Inert against the build-up of micro organisms
- Resistant against UV light, oxygen and ozone
- Efficient electronic insulator with high dielectric strength
- High gas permeability
- Good wetting properties when bonded with glass
The good separating effect of silicone is utilized in mold making to produce precision molds made of synthetic resin, with demolding being facilitated by the high elasticity of silicone.
Silicone has a very low surface energy and very little wettability. Atmospheric plasma treatment allows for the surface energy to be enhanced substantially for better adhesion. It is to be noted that surface energy is recovered within the short timespan of minutes, especially by silicones with low shore hardness