High temperature vulcanized silicone rubber is a kind of polyorganosiloxane (i.e. raw rubber) with high molecular weight (generally 400000-800000) added with reinforcing filler and other additives, which is formed by pressure molding (molding, extrusion, calendering) or injection molding with organic peroxide as the curing agent and cross-linked at high temperature. This rubber is generally referred to as silicone rubber.
The vulcanization of high-temperature vulcanized silicone rubber is generally divided into two stages. The first stage is to mix the raw silicone rubber, reinforcing agent, additive, vulcanizing agent and structure control agent, and then pressurize, heat, shape and vulcanize the mixture in the metal mold. The pressure is about 50 kg/cm2, the temperature is 120~130 β, and the time is 10~30 minutes. The second stage is to take the silicone rubber out of the mold and put it into the oven, Bake for several hours to 24 hours at 200~250 β. The rubber is further vulcanized, and the organic peroxide is decomposed and volatilized at the same time.
The reinforcing filler of silicone rubber is various types of white carbon black, which can increase the strength of vulcanizate by ten times. Adding various additives is mainly to reduce the cost of rubber, improve the properties of rubber compound and endow various special properties of vulcanizate, such as flame retardancy and conductivity. Crosslinking agents are various organic peroxides, such as benzoyl peroxide, 2,4-dichloroperoxybenzoyl peroxide, cumyl peroxide, 2,5-di-tert-butylperoxyhexane, etc The structure control agent is added to prevent the mixture from being placed for too long, producing "structure" to make the rubber hard and difficult to process and mature. Methyl hydroxy silicone oil or diphenyl dihydroxy decane can be used as the structure control agent.
The side groups on the main chain of silicone rubber can be methyl, ethyl, vinyl, phenyl, trifluoropropyl, etc. Methyl is the most commonly used, and other groups can also be introduced to improve the processability and other properties. Therefore, according to the different side group and rubber compound formula, silicone rubber with different uses can be obtained, which can be generally divided into the following types: general-purpose (containing methyl and vinyl), high-temperature and low-temperature (containing phenyl, methyl and vinyl), low compression permanent set (containing methyl and vinyl), low shrinkage (devolatilization) and solvent resistant (fluorosilicone rubber).
For high-temperature vulcanized silicone rubber, see details:
https://www.rtvsilicone.net/product-high-rebound-grade-htv-silicone-rubber-.html 
