The structure of silicone resin is shown in Figure 1. Because the bond energy of Si -- O bond is very high (452kJ/mol), which is much higher than that of C -- C bond (345.6kJ/mol) and C -- O bond (357.7kJ/mol), the main chain of Si -- O -- Si is very stable, has good weather resistance, and is difficult to generate free radical and oxidation reaction. In addition, due to the silicone resin side chain containing methyl (hydrophobic groups), this will undoubtedly further enhance the silicone coating water resistance.
Therefore, silicone resin coating is a kind of insulation coating with heat resistance, cold resistance and weather resistance outstanding. Main performance description:
The heat resistance of silicone resin coating is strong
The main factors of high temperature resistance, because the main chain of the Si - O - Si keys can be high, with the rising of the temperature, the organic groups in the organic silicon resin, such as methyl, phenyl will gradually decompose, above 350 ℃, organic silicon resin silica silica skeleton will completely decomposed into inorganic silica crosslinking structure, make the silicone heat resistant coatings "second film," Forming a new high temperature resistant silicified layer.
Heat resistance is also the biggest characteristic of silicone resin coatings. Pure silicone resin varnish can withstand 200-250 ℃ high temperature, when the coating prepared with sheet aluminum powder, glass material, heat resistant filler can withstand 300-700 ℃ high temperature, modified silicone resin and high temperature pigment can be made resistant to 200-300 ℃ high temperature coating. Resistant to boiling water and superheated steam after drying.
② silicone resin coating has excellent weather resistance
The pure silicone resin coating still has good impact strength and flexibility at -50 ℃. After being modified by polyester, it can be used at -80 ℃.