The chemical composition is silicone resin. Using water, diphenyldichlorosilane, one phenyltrichlorosilane, methyl vinyl dichlorosilane, dimethyl dichlorosilane and solvent as raw materials, through hydrolysis, neutralization, centrifugation, concentration, catalytic polymerization. This product is a kind of thermosetting resin. Because its internal junction contains diameter base, adding filler, additives, catalysts can be molded into silicone plastic under heating and pressure. This mold plastic has good high and low temperature performance, the use of temperature in a BC ---25D}:. Has good electrical properties, in high temperature, high humidity, high frequency electrical properties change little. Good moisture resistance, water absorption is very small. It has excellent resistance to machinery and impact of temperature. It has good radiation resistance. It also has good resistance to ozone and ultraviolet light. Yellow to tan viscous liquid or solid: gelation time 1--4min [2Sp}_, according to laboratory gelation plate). Acid value not greater than 0.5. Thermal weight loss not greater than 596 [}(}p}: , 3H), the base content is Q.5% to 5%(by aluminum hydrate chromatography determination by the base). Used as the basic raw material of silicone molding plastics. Suitable for encapsulating diodes, small power tubes, high power tubes and win!, and small-scale integrated circuits.