Hot vulcanized silicone rubber is a kind of high molar mass (generally 40×104 ~ 80× 104G /mol) linear polydiorganic siloxane, non-vulcanized (crosslinked) base polysiloxane is called silicone rubber rubber, adding reinforcing filler and other additives, using peroxide vulcanization or addition reaction crosslinking, by pressure molding or injection molding, And at high temperature vulcanized into the network structure of the elastomer is vulcanized rubber, in aerospace, electronics, household appliances, solar energy, machinery, high-speed railway, automobile, instrumentation, food, medicine and health and other fields have a wide range of applications.

(1) silicone rubber rubber

The main silicone rubber rubber has two methyl silicone rubber rubber, methyl vinyl silicone rubber rubber, methyl phenyl vinyl silicone rubber rubber and methyl trifluoropropyl silicone rubber rubber four types. At present, the polymerization of raw rubber in China is produced in two ways: batch method and continuous method. Generally, eight methyl cyclotetrasiloxane (D4), dimethyl siloxane mixed ring (DMC), methyl vinyl mixed ring (VMC) and vinyl end low viscosity silicone oil are used as raw materials and Me4NOH is used as catalyst. After dehydration, ring-opening polymerization, destruction of catalyst and vacuum removal of low molecular material, silicone rubber rubber was obtained.

1, dimethyl silicone rubber rubber (MQ)

Chemical structure and dimethyl silicone oil, but the degree of polymerization is much higher, is the earliest use of silicone rubber rubber. The raw rubber of dimethyl silicone rubber is semisolid, the relative density is 0.98 and the refractive index is 1.4035. Because the silicon atom is connected to the inert methyl, so the vulcanization activity is low, vulcanized rubber mechanical strength is poor, high temperature compression permanent deformation, heat resistance is poor, is now rarely used, basically replaced by methyl vinyl silicone rubber rubber.

2, methyl vinyl silicone rubber (VMQ)

The chemical formula is RMe2SiO(Me2SiO) N (MeViSiO)mSiMe2R (R is Me or Vi), the MeViSiO chain in the rubber generally accounts for only 0.05-0.5% (mol), so its relative density, refractive index, and molar mass are close to the dimethyl silicone rubber rubber. However, a small amount of vinyl can greatly improve the vulcanization activity, improve the heat-resistant aging, mechanical strength and permanent deformation properties of vulcanized rubber, has become the largest and the most representative silicone rubber.

3, methyl phenyl vinyl silicone rubber rubber (phenyl silicone rubber rubber, PVMQ)

Phenylsilicone rubber raw rubber is the product of methyl vinyl silicone rubber raw rubber after some methyl is replaced by phenyl. Its relative density and refractive index are related to the content of phenyl, and the refractive index increases with the increase of the content of phenyl. The mechanical strength, radiation resistance, heat resistance and flame retardancy of vulcanized rubber can be improved by introducing phenyl group into raw rubber.

4, methyl trifluoropropyl silicone rubber rubber (fluorosilicone rubber rubber, FVMQ)

The strong polarity OF Me(CF3CH2CH2)SiO chain is introduced into the raw rubber of fluorosilicone rubber, which can effectively improve the oil and solvent resistance of vulcanized rubber, and the cold resistance and compression permanent deformation is better than that of ordinary fluorosilicone rubber.

(2) mixed silicone rubber and its products

The mixing method of silicone rubber is similar to that of synthetic rubber, and the basic formula is relatively simple. Add white carbon black in rubber, part of the varieties of mixed with functional fillers and additives in a kneading machine, through mixing, parking, filter, get the finished mixing rubber, silicone rubber according to application needs to be processed into plate, sheet, belt, bars, circles of different shape, different color, such as silicone rubber bricks, formed after vulcanization silicone rubber products; It can also be produced by continuous extrusion and vulcanization process.

With different raw rubber, different process formula, different vulcanization method can be processed into general type, high temperature resistance, low temperature resistance, high strength, high tear resistance, thermal conductivity, electrical conductivity, flame retardant and other different types of silicone rubber products.