RTV-2 silicone rubbers are two-part pourable, spreadable or kneadable compositions that vulcanize when the curing agent component is added and form highly elastic silicone rubber. They are cured at room temperature (RTV = room-temperature vulcanizing). There are two ways of vulcanizing them: In condensation-curing, an organotin catalyst is usually used; alcohol is produced as a byproduct. Addition curing, on the other hand, uses a platinum catalyst and does not produce byproducts. Special silicone rubber grades can be flash vulcanized using UV light. The vulcanization time can be controlled by adjusting the UV intensity and exposure time. Most cured RTV-2 sillcone rubbers retain their full elasticity up to 200°C. Some products can even be briefly heated to 300°C. At low temperatures, they retain their flexibility down to -50°C, or even to -100°C in the case of special grades.
By choosing particularly slow-acting Pt catalysts, WACKER also offers you a range of premixed one-part systems with a long shelf life, which only vulcanize at elevated temperature. Based on the polymer structure, which is analogous to addition-curing RTV-2 silicone rubber grades, this group, too, is classified as RTV-2. The thermal conductivity of RTV-2 silicone rubber generally allows them to be used for insulating electrical power equipment without causing overheating. The most useful electrical properties are the insulation resistance, breakdown resistance and dissipation factor. The gas permeability of RTV-2 silicone rubbers is around ten times higher than that of natural rubber at room temperature. Another feature that is advantageous in many applications is the excellent release property of the cured rubber surfaces towards organic and inorganic materials.
The extensive portfolio of RTV-2 silicone rubber products allows cured rubbers to be produced with extremely versatile, highly specialized properties. This results in a versatile, successful solution portfolio for individual problems in diverse industrial areas, such as moldmaking, electronics and optoelectronics, household appliances, mechanical engineering and industrial process engineering, health care applications and solar/photovoltaics.