Introduction of Silicone Resin (I)


What is silicone resin? Silicone resins are semi-inorganic and semi-organic polymers with Si-O as the main chain and organic groups in the side chain. Silicone resin is a bulk polymer with many active groups. These active groups are further cross-linked, i.e. into insoluble and insoluble curing products of three-dimensional structure.


Silicone resin has excellent properties such as high and low temperature resistance, weather aging resistance, water-repellent and moisture-proof, high insulation strength, low dielectric loss, arc resistance and radiation resistance.


General solution silicone resins are mainly used as basic polymers for heat resistant coatings, weatherproof coatings and high temperature electrical insulation materials.


1. Technical Evolution of Silicone Resin






Among all kinds of organosilicon polymers, silicone resin is the first kind of organosilicon products synthesized and applied. Compared with the rapid development of silicone rubber pattern renovation technology, the technological upgrading of organosilicon resin is relatively slow and the major technological breakthroughs are less. Since about 20 years ago, due to the technological progress of aromatic heterocyclic heat-resistant polymers, some of them originally belong to the application field of silicone resins. However, the solvent toxicity and harsh curing conditions of aromatic heterocyclic heat-resistant polymers limit the expansion of applications. In recent years, more attention has been paid to the research and development of silicone resins. Silicone resin has many outstanding advantages, such as wide temperature range, good ageing resistance and hydrophobic and moisture-proof performance. There are signs that silicone resin may have a larger development space in the future.


2. General silicone resin


2.1 Production Technology of Universal Silicone Resin


Different kinds of silicone resin have different raw materials and synthetic routes. In this paper, the production process of several kinds of silicone resins is simply introduced.


2.1.1 Methyl Silicone Resin


2.2.1.1 Synthesis of methyl silicone resin from methyl chlorosilane


Methyl silicone resin was synthesized with methyl chlorosilane as the main raw material. Because of the different structure and composition of silicone resin (the crosslinking degree of silicone resin, i.e. [CH3]/[Si]), different synthetic conditions were needed.


When synthesizing low R/Si ([CH3]/[Si] 1.0) methyl silicone resin, the hydrolysis and condensation reaction speed of methyl trichlorosilane, the main raw material monomer, is quite fast. The reaction temperature must be strictly controlled not to exceed 0 C, and the reaction must be carried out in composite solvents. Moreover, the storage life of the reaction product at room temperature is only a few days. This kind of product has little practical value.


Methyltrichlorosilane was used to synthesize methylsilane resin with larger R/Si ratio. Although the hydrolytic condensation reaction of the mixture of methyltrichlorosilane and dimethyldichlorosilane was slightly slower than that of methyltrichlorosilane alone, the hydrolytic condensation reaction rate of methyltrichlorosilane and dimethyldichlorosilane was too different, often due to the difference of the reaction rate between methyltrichlorosilane and dimethyldichlorosilane The mixed hydrolysates obtained from the three chlorosilane are not consistent with the proportions of the two monomers, and the methyl chlorosilane is often hydrolyzed to form a local crosslinking gel. The resulting silicone resin has poor comprehensive properties at the end of two.


From Silicone Innovation Institute