ELASTOSIL® LR 3020/60 is a two-component liquid silicone rubber compound, which is optimized for injection molding and vulcanizes rapidly via a platinum-catalyzed addition reaction. A special feature is its high steam-resistance once the silicone is cured. Standard silicone elastomers can only withstand superheated steam for short periods, making suitable for such applications to a very limited extent. The reason for this is that silicone elastomers generally hydrolyze under these conditions, i.e. are chemically decomposed by water. This reduces their elastic recovery under pressure. As a result, the seal leaks.
This cannot happen with the new ELASTOSIL® LR 3020/60 grade. It is largely resistant to hydrolysis and even retains its elasticity in persistent contact with superheated steam. Measurements show that postcured test specimens made from ELASTOSIL® LR 3020/60 stored for 21 days in autoclaves with steam at 150 degrees Celsius have a compression set of 62 percent. They thus retain sufficient high elastic recovery for sealing purposes. The other mechanical properties of the elastomer, such as elasticity and tensile strength, have been substantially improved.
Compared with all currently available hot-water- and steam-resistant solid silicone rubbers, ELASTOSIL® LR 3020/60 also provides processing advantages. As a fast-curing liquid silicone rubber, the grade allows particularly short cycle times during injection molding. Elastomer products can be precision manufactured with virtually no waste. Thus, for the first time ever, plastics processors can use a hydrolytically stable silicone rubber for large-scale production, enabling the cost-effective manufacture of seals.
Molded parts made from ELASTOSIL® LR 3020/60 are suitable for applications that are regularly exposed to hot water and steam. Typical examples include molded gaskets for domestic appliances such as espresso machines or steam irons, medical equipment, sanitary engineering, heating and power plant technology.
The cured products of the new silicone provide a further advantage: they are more resistant than standard liquid silicones to many of the conventional disinfectants and cleaning agents used in medical engineering. Postcured vulcanizates of the new silicone grade are food-compatible and meet the requirements of the German Federal Institute for Risk Assessment (BfR) and the US Food and Drug Administration (FDA). They also meet the requirements of the hygiene guidelines of the German Federal Environment Agency (UBA) for seals and equipment in warm and cold water applications.