Study On High Temperature Resistant Silicone Coatings

High temperature resistant coating, also known as heat-resistant coating, is a kind of functional coating, which generally does not change color or fall off, can still maintain appropriate physical and mechanical properties to make objects work well under above 200℃. High temperature resistant coating consists of film former, filler, additives and solvent. According to film former, high temperature resistant coating can generally be divided into organic high temperature resistant coating and inorganic high temperature resistant coatings. As an important branch of organic high temperature resistant coating, studies about organic silicon heat resistant coating are wide. Epoxy modified silicone resin is prepared by epoxy resin and silicone resin, so it has good qualities of both epoxy resin and silicone resin, including excellent thermal stability, strong adhesion, and the ability of room temperature curing, etc.A kind of heat insulation and ablation-resistant epoxy modified silicone coating was prepared by mixing several materials, including film former like epoxy modified silicone resin; filler like hollow glass beads, kaolin, mica powder, titanium dioxide and talcum powder; additives like anti-settling agent, compound flame retardants, and anti foaming agent; solvent like dimethylbenzene. The performance of coating was evaluated and analyzed by thermal conductivity, density, TGA, adhesion, oxygen acetylene ablation, and heat insulation tests. The influence of ratio of resin, hollow glass beads and flame retardant on coatings was discussed. A kind of coating with good integrated properties was made by changing formulation of coating at last.The experimental results show that: 1) The choice of epoxy modified silicone resin has great effect on the heat-resistant property of coating. Epoxy modified silicone resin HG-43 with less thermal weightlessness rate can increase the initial decomposition temperature, mass residual rate at 900℃ of coating respectively by 14℃, 8.74%, compared to resin SH-023-7. 2) The addition of flame retardants in formulation 2# can make the oxygen-acetylene line ablation rate of coating vary from 0.365mm/s to 0.310mm/s, a reduction of 15.07%. The ratio of flame retardants is more, and the effect is better. 3) Thethermal conductivity of coating vary from 0.236W/( m·K) to 0.232W/( m·K) when the ratio of hollow glass beads increase from 12% to 18% accordingly, so its heat resistant property is better. 4) The adhesion between carbon fiber composite material plate and self-made coating 7# reach grade 2, its surface hardness reach 4H as well as. The density of self-made coating is 1.283g/cm3. When carbon fiber composite material plate is under the temperature of 530℃, its back temperature increase from room temperature to 155℃ rapidly during 30 seconds.While the front of plate is coverd by self-made coating 7# with the thickness of 1mm, its back temperature decrease to 60.8℃ during the same 30 seconds. The heat resistant performance of self-made coating is good. 5) The self-made coating can be used to protect carbon fiber composite material from high heat, and it can be cured at room temperature.