Silicone coating resistant weathering-HongYe silic...

Silicone coating resistant weathering       People usually use the paint is coated on the surface of metal parts and other materials to prevent the corrosion, but organic varnish and enamels no heat, when the temperature is higher than 150 ℃ most organic resin carbonization, and when the temperature is lower than -50 to -70 ℃ and brittle, resulting from the material surface coating. Silicone resin has excellent high temperature resistant and weather resistant performance, make it an ideal material for high temperature coatings.      Silicone coating in addition to heat, also has a weather resistance, resistance to water, gas and steam, ozone and ultraviolet degradation characteristics. Therefore, at present, has been widely used as heat resistant anticorrosive paint flue gas, boiler, furnace, various heaters, cement calciner, petroleum cracking furnace etc..    And as the aircraft, missiles, spacecraft and other insulation protective coating, which can work at 250-300 ℃, long-term, and maintain the color and luster.       Heat resistant silicone coating is usually divided into two categories: 500 ° F (260 ℃) following use and 500 to 1200 ° F (650 ℃) within the scope of the use of paint. The former usually with modified silicone resin (silicon content of about 25 to 30%) as the base material, the latter is higher silicon content. Use the higher the temperature, the higher content of organosilicon need. In the preparation of silicone heat-resistant coating, in addition to silicon resin solution to film, also need to add filler (such as mica powder, talcum powder, glass powder) and pigment (usually use inorganic pigments, thermally stable aluminum, zinc powder, carbon black). As the curing speed of film, the catalyst can be used in various. A catalyst for zincate or naphthenate cobalt, zinc, magnesium and iron, zinc acid salt is the best. The amount of catalyst is generally 0.1% to 0.2%, highest do not exceed 0.3%. In practical application, sometimes need not add any fillers, pigments, including without aluminum powder, temperature resistant varnish zinc powder, glass ceramic material. Shandong University four phenyl trimethoxy silane and borate and silicate cocondensation (molar ratio of 1:1 or 1:2), developed a heat-resistant silicone resin paint, varnish coating on the copper, shiny bright, after 10 hours at 500 ℃ after aging, copper is not oxidized, coating to keep gloss, fast bake copper is an adhesion test, impact strength is 50 kg, cm. Compared with the uncoated copper, in the same circumstances copper oxidation discoloration. As with aluminum powder blend, resistance to high temperature of 700 ℃. China has successfully developed many kinds of silicone ablation thermal insulation coatings, such as type YJ-66A and 751 type paint. These two kinds of coatings with high temperature air scour and insulation resistance of flame ablation resistance, high strength, excellent. Type YJ-66 coating ablation rate in oxygen kerosene rocket engine under 0.12 to 0.2 mm / S; 751 coating (0.5 mm thick) through the back temperature 1600 ℃ *30 seconds oxyacetylene ablation after less than 200 DEG C, weight loss is less than 0.2%. In the silicone abloation adding silane coupling agent can improve the thermal insulation coating, the coating viscosity and dispersion, improve the anti-corrosion and water resistance of the coating, the adhesion force increased substrate, reduce paint curing temperature, improve physical and mechanical properties of the coating.