Silicone elastomers differ from other elastomers in that they are not purely organic compounds. Instead of the carbon polymer chain of normal elastomers, the silicone polymer chain consists of alternating silicone and oxygen atoms (siloxanes).
Silicone rubbers are differentiated according to their aggregate state (solid/liquid) and their vulcanisation temperature:
Silicone elastomers are very resistant to heat, ozone, ageing and chemicals. The mechanical properties, however, are rather below those of other elastomers.
In order to achieve optimum heat resistance, post-curing is necessary in many cases.
Silicone rubber is flame retardant and physiologically inert, but has a high gas permeability. Silicone elastomers are resistant to hot water, vegetable and animal fats, paraffinic mineral oils as well as glycol and alcohols.
|Hardness||20 to 80 Shore A|
|Elongation at break||100 to 600|
|Maximum temperature||+180° C|
|Electrical properties||excellent insulating properties even at higher temperatures, but can also be made extremely conductive|
|Gas permeability||worst gas tightness of all elastomers|
|Resistance to ageing and ozone||excellent|
Elastomers made of hot vulcanising solid (HTV) and liquid (LSR) silicone rubber are used in pharmaceutical and medical articles as well as in many articles that come into contact with food.
Other technical applications include hoses, membranes, cables, and seals for the aerospace industry.
Seals for freezers, cookers, drying cabinets, shaft seals, O-rings, switch mats as well as electrical insulation for ships, aircraft, heating cabinets.