Methyl silicone resin was synthesized from methyl chlorosilane
1. Methyl chlorosilane is used as the main raw material to synthesize methyl silicone resin. Due to the different structure and composition of silicone resin (the cross-linking degree of silicone resin, namely [CH3] / [Si] value), different synthesis process conditions are required.
When synthesizing low R/Si ([CH3] / [Si] ≈1.0) methyl silicone resin, the hydrolysis and condensation reaction speed of the main raw material monomer methyl trichlorosilane is quite fast. The reaction temperature must be strictly controlled not to exceed 0℃, and the reaction must be carried out in the compound solvent, and the storage period of the reaction product is only several days at room temperature. Such products are of little practical value.
Application of synthesis of methyl chlorosilane R/Si larger methyl silicone resin, although methyl trichlorosilane with dimethyl dichloride silane hydrolysis condensation reaction mixture is relatively simple in the hydrolysis of methyl trichlorosilane condensation reaction is a bit slower, but methyl trichlorosilane and dimethyl dichloride silane hydrolysis condensation reaction speed difference is too big, often because of methyl trichlorosilane hydrolytic condensation in advance, The ratio of the mixed hydrolysate and the raw material monomer is not consistent, and methyltrichlorosilane is often hydrolyzed and condensed in advance to form a local cross-linked gel, and the comprehensive performance of the methyl silicone resin is poor.

2. Synthesis of methyl silicone resin from methyl alkoxy silane
The rate of hydrolysis and condensation reaction of methyl alkoxy silane can be controlled by changing reaction conditions. Starting from methyl alkoxy silane, methyl silicone resins with different cross-linking degrees can be synthesized.
Commercial methyl silicone resins with medium crosslinking degree ([CH3] / [Si] ≈1.2 ~ 1.5) are mostly prepared by hydrolysis condensation reaction of methyl alkoxy silane: The methyl triethoxy silane and dimethyl diethoxy silane monomers purified by deacidification were mixed with water, and a trace of hydrochloric acid or an appropriate amount of strong acid type cation exchange resin (macroporous strong acid type ion exchange resin has better catalytic effect) and active clay (dried after acidification treatment) were used as catalysts, heated and hydrolyzed. At the end point, an appropriate amount of HCl was added to neutralize the catalyst, or the ion exchange resin or active clay used as catalyst was removed to terminate the condensation reaction. The resulting product is an alcohol solution of methyl silicone.