High temperature vulcanized silicone rubber is high molecular weight (molecular weight is generally 400,000 ~ 800,000) of polysiloxane (that is, raw rubber) to add reinforcing filler and other additives, using organic peroxide as vulcanizing agent, by pressure molding (molding, extrusion, calendering) or injection molding, and at high temperature cross chain into rubber. This kind of rubber is commonly referred to as silicone rubber.
High temperature vulcanization silicone rubber vulcanization generally divided into two stages, the first phase is the silicon rubber, reinforcing agent, additives, mixing vulcanizing agent and structure control agent, and then heat the mixing material in metal mould pressing forming and vulcanization, the pressure is about 50 kg/cm2, the temperature is 120 ~ 130 ℃, time of 10 ~ 30 minutes, The second stage is to take the silicon rubber out of the mold, put it into the oven, and dry it for several hours to 24 hours at 200 ~ 250℃. The rubber is further vulcanized while the organic peroxides are decomposed and volatilized.

The reinforcing filler of silicone rubber is various types of silica, which can increase the strength of vulcanized rubber ten times. Adding various additives is mainly to reduce the cost of the glue, improve the properties of the glue and give the vulcanized rubber a variety of special properties such as flame retardant, conductive, etc.. Crosslinking agent is a variety of organic peroxides, such as benzoyl peroxide,2, 4-dichloro benzoyl peroxide, dichloro peroxide,2, 5-dichloro butyl peroxide hexane and so on. Structure control agent is to avoid mixing compound placed for too long, the "structure" to make the compound hard hard, difficult to process and mature and add, can use methyl hydroxyl silicone oil or diphenyl dihydroxyl seize alkane as structure control agent.

The side groups on the main chain of silicone rubber can be methyl, ethyl, vinyl, phenyl, trifluoropropyl and so on. Methyl groups are most commonly used, but other groups can be introduced to improve processing properties and other properties. Therefore, depending on the side base groups and sizing formula, can get all kinds of different USES silicon rubber, they can generally be divided into the following several types: general type (including methyl and vinyl), high temperature and low temperature type (including phenyl methyl and vinyl), low compression permanent deformation (including methyl and vinyl), low shrinkage (volatile) and resistance to solvent (fluorine silicone rubber), etc.

1.methyl silicone rubber

Dimethyl silicone rubber is one of the earliest commercial production of silicone rubber, can be in the range of -60 ~ 200℃ to maintain good elasticity, good aging resistance, excellent electrical insulation performance and moisture-proof, shockproof and physiological inertia characteristics.
Dimethyl silicone rubber is mainly used for strong coating, can also be made into a variety of extrusion and calendering products used in electromechanical, aviation, automobile and medical and other industries. But because of the dimethyl silicone rubber vulcanization activity is low, used for the manufacture of thick products, vulcanization is difficult, the inner layer is easy to bubble and high temperature compression permanent deformation, so it has been replaced by methyl vinyl silicone rubber.