Typical silicone resins are organosilicon polymers with active reactive groups. In order to improve the hardness of silicone resin curing materials, the following two means are commonly used: ① improve the functional degree of silicone polymer, that is, reduce the R/Si value of silicone resin components; ② Silicone polymer side chain group all use the shortest chain organic group - methyl, and avoid the use of phenyl side chain group.
As mentioned above, the synthesis process route of methyl silicone resin is to prepare silicone resin with high hardness, namely methyl silicone resin with high cross-linking degree or ultra-high cross-linking degree. In order to avoid the cross-linking gel produced in the hydrolysis process, methyl chlorosilane is not suitable to be used as the raw material, but alkoxy silane can only be used.
It is difficult to control the process of synthesis of methyl silicone resin with high crosslinking degree, especially high crosslinking degree. The main problem is that gel components are easy to form in the silicone solution obtained by synthesis reaction.
The presence of such gel centers must be avoided in order to produce high cross-linking methyl silicone resins with stable storage. Its technology is the key to effective control of hydrolytic condensation reaction stable equilibrium, the feasible technical method is to use a mild moderate catalyst and controllable synthesis process, control process of hydrolytic condensation reaction of organic silicon monomer, avoid too much "beat" four faculties monomer hydrolysis and condensation "alone", so as to prevent formation of gel center, and get the structure stability of the polymer.