Curing additives
In addition to RTV and liquid vulcanization systems, silicone rubber is typically vulcanized using peroxides such as benzoyl peroxide, 2,4-dichlorobenzoyl, tert butyl benzoate, and diisopropyl peroxide. Alkyl hydroperoxides and dialkyl peroxides have also been successfully used in silicone containing vinyl groups.
Hydrosilylation or hydrosilylation is an alternative curing method for vinylsiloxanes, utilizing hydrogen silane materials and platinum containing compounds as catalysts. This is a two part process that requires mixing two different components, resulting in a limited shelf life of the material. Curing does not produce volatiles, and traditional thermal cured silicone resins with high tear strength can be cured in this way.
filler
Adding reinforcing fillers is to improve the poor tensile strength of silicone resin in other aspects. Despite the use of carbon black, silica in the form of silica fume with a particle size in the range of 10-40 nanometers is the most preferred filler. The filler does indeed interact with vulcanized rubber, forming false vulcanization. This may occur during the mixing process (creep hardening) or during the storage process (silo aging).
Although grinding can destroy these structures, structure control additives or ant structure additives are usually added to counteract these reactions. Examples of these materials are based on siloxane materials, such as diphenylsilane and pinacol dimethylsilane.
Other additives
Compared with natural rubber, silicone resin has better fire resistance. This performance can be improved by adding flame retardant additives such as platinum compounds, carbon black, trihydrate aluminum, zinc or cerium compounds. It should be noted that the addition of carbon black also increases conductivity. Iron oxide, titanium dioxide, and other organic metal compounds can also be added as pigments to improve thermal stability.
Click to view more organic silicon products