Raw gum
Methylvinyl silicone rubber is mainly used. It is also possible to use high temperature vulcanized vinyl-terminated methyl vinyl silicone rubber, that is, dimethylsiloxane-methylvinylsiloxane copolymer terminated with dimethylvinylsiloxane. This silicone rubber can be vulcanized by addition vulcanization system. The vulcanizate has high tear strength and low compression set, and is suitable for fire-resistant silicone rubber sealing strip. If you need materials with better ablation resistance, you can choose phenyl silicone rubber or methyl phenyl vinyl silicone rubber. The ablation rate of phenyl silicone rubber is about 1/2 of that of vinyl silicone rubber. Because of its high price, it is only used for special purposes.

Reinforcing filler
White carbon black is used, mainly the fumed white carbon black, but also the precipitated white carbon black. The surface treatment of silica can improve the strength and hydrophobicity of silicone rubber vulcanizate. Surface treatment agents include silane coupling agent, octamethylcyclotetrasiloxane, etc.

Incremental fill
Incremental fillers only play a weak reinforcing role on silicone rubber, and are generally used together with silica to adjust the hardness of silicone rubber vulcanizates, improve the processing properties of rubber compound (such as extrusion performance) and reduce costs. It mainly includes quartz powder, diatomite, zinc oxide, titanium dioxide, talc powder and calcium carbonate. The silica powder treated with silane coupling agent not only improves the reinforcement, but also acts as a sintering binder and contributes to the ceramics.

Structural control agent
In order to suppress the "structure" of silicone rubber compound reinforced by fumed silica and ensure the processing performance, it is necessary to add structural control agent. Generally, hydroxy silicone oil is used (the mass fraction of hydroxyl is 0.06~0.12).

Heat stabilizer
The heat stabilizer generally uses selenium oxide, selenium hydroxide or caproate, iron oxide or iron caproate, etc.