Thermal vulcanized silicone rubber refers to silicone rubber with high relative molecular weight (400,000 ~ 600,000). Using organic peroxides as vulcanizing agents, the organic peroxides are decomposed by heating to produce free groups, and the organic side base form of rubber is linked to obtain vulcanizing rubber.
Variety and characteristic：
(1) dimethyl silicone rubber dimethyl silicone rubber (polydimethylsiloxanerubber) methyl silicone rubber, silicone rubber is the oldest varieties. It can maintain good elasticity in the temperature range of -60 ~ 250℃. Due to the shortcomings of low vulcanization activity, poor process performance, easy foaming during two-stage vulcanization of thick wall products, high temperature compression deformation, etc., it has been replaced by methyl vinyl silicone rubber except for a small amount of fabric coating.
(2) methyl vinyl silicone rubber methyl vinyl silicone rubber (methylvinylpolysiloxanerubber) vinyl silicone rubber, is by dimethyl siloxane and a small amount of vinyl siloxane copolymer, vinyl mole fraction of 0.001 ~ 0.003 in general. The introduction of a small amount of unsaturated vinyl has greatly improved the vulcanization process and finished product properties, especially the heat aging property and high temperature compression deformation resistance. In the production of silicone rubber, methyl vinyl silicone rubber has the largest output, the most widely used, and the most varieties, in addition to a large number of general-purpose rubber materials, a variety of special silicone rubber and silicone rubber with processing characteristics (such as high-strength silicone rubber, low compression permanent deformation silicone rubber, conductive silicone rubber, thermal silicone rubber, and no two-stage vulcanized silicone rubber, particle silicone rubber, etc.) are also based on it The basis for processing.
(3) methyl vinyl phenyl methyl vinyl silicone rubber phenyl silicone rubber (methylvinylphenylpolysiloxanerubber) phenyl silicone rubber, is introduced in the molecular chain of vinyl silicone rubber diphenyl silane link (or methyl phenyl siloxane chain section) and made of. When the molar fraction of phenyl is 0.05 ~ 0.10, it is collectively referred to as low phenyl silicone rubber, at this time, the hardening temperature of rubber is reduced to the lowest value (-115 ° C), so that it has the best low temperature resistance, and is still elastic below -100 ° C. With the increase of the molar fraction of phenyl, the rigidity of the molecular chain also increases, and the crystallization temperature increases.
(4) Methyl vinyl trifluoropropyl silicone rubber Three fluorine propyl methyl vinyl silicone rubber (methylvinylrtrifluoropropylpolysiloxanerubber) fluorine silicone rubber (fluorosilicorubber), is introduced in the molecular chain of vinyl silicone rubber fluoro alkyl (generally for three fluorine propyl), has the best Good resistance to oil and solvent. For example, for aliphatic, aromatic and chlorinated hydrocarbon solvents, petroleum-based fuel oils, lubricating oils, hydraulic oils and some synthetic oils, their operating temperature range is -50 ~ 250℃, and they are stable at room temperature and high temperature.