Silicone resins Silicone resins are highly cross-linked reticulated polyorganosiloxanes, usually obtained by acidic hydrolysis of various mixtures of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyl dichlorosilane, or methylphenyldichlorosilane, decomposed by addition of water in the presence of an organic solvent such as toluene at a relatively low temperature. The initial product of hydrolysis is a mixture of cyclic, linear and cross-linked polymers, usually also containing a considerable number of hydroxyl groups. The hydrolysate is washed with water to remove the acid, and the neutral primary condensate is thermally oxidized in air or further condensed in the presence of a catalyst to finally form a highly crosslinked, three-dimensional network structure. 　　Silicone resin is a thermosetting plastic, one of its most outstanding performance is excellent thermal oxidation stability. 250 ℃ heating for 24 hours, silicone resin weight loss of only 2 ~ 8%. Silicone resin is another outstanding performance is excellent electrical insulation properties, it is in a wide range of temperatures and frequencies can maintain its good insulation properties. 　　In view of the above characteristics, silicone resin is mainly used as insulating varnish (including varnish, enamel, color varnish, impregnating varnish, etc.) to impregnate H-class motor and transformer coils, as well as used to impregnate glass cloth, glass cloth silk and asbestos cloth made of motor casing, electrical insulation windings and so on. Silicone insulating varnish can be bonded to mica to produce large-area mica sheet insulating material, which is used as the main insulation of high-voltage motors. In addition, silicone resin can also be used as heat-resistant, weather-resistant corrosion-resistant coatings, metal protective coatings, waterproof and moisture-proof coatings for construction projects, mold release agents, adhesives, and the secondary processing of silicone plastics for the electronics, electrical and defense industries, as semiconductor packaging materials and electronic, electrical parts and components of the insulating material. 　　Silicone resin according to its main purpose and crosslinking can be broadly divided into silicone insulating paints, silicone coatings, silicone plastics and silicone adhesives and other major categories.