High temperature resistant powder coating is a special functional coating. It not only has the properties of ordinary coatings, but also has heat resistance, corrosion resistance and weather resistance. It is commonly used in barbecues, heaters, high-power lighting, and heating pipes. , Hot blast stoves, silencers, ovens, high-temperature furnaces, motorcycle exhaust pipes, chimneys and other high-temperature equipment. High temperature resistant powder coatings will gradually replace traditional high temperature resistant coatings due to their common environmental protection, safety, high application rate and good performance.
It is a thermosetting coating, and its coating constitutes a network cross-bonding structure, so it has a certain improvement in heat resistance compared with thermoplastic coatings. The heat resistance test of epoxy type, epoxy/polyester hybrid type, polyester/TGIC type and other powder coatings indicates that these coatings can basically be used for a long time under the condition of lower than 150℃, but when the temperature is higher than 250 In an environment of ℃, the coating exhibits damage such as loss of gloss, force drop, coating embrittlement, reduced flexibility, chalking, etc., which makes the coating lose its maintenance effect on the substrate. At present, the most commonly used heat-resistant resin There are mainly organosilicon-oxygen bonds as the main chain. Due to its high bond energy, it has high oxidation stability, and silicone resin can form a stable chain maintenance layer on the surface of the coating, reducing the internal impact of the polymer. Silicone resins are widely used in heat-resistant coatings. Generally, the application and selection factors of silicone resins are as follows:
—The order of side groups to thermal stability: phenyl>methyl>ethyl>propyl>butyl>hexyl;
—The content of silica affects the temperature resistance of the coating;
-Silanol content affects the cross-chain density of silicone resin;
—TG affects the storage and sprayability of the coating.
Select the type and amount of silicone resin to be added according to the temperature requirements and use time. At present, the more commonly used high-temperature resistant powder coatings for BBQ are around 350℃, while the exhaust pipe and radiator require temperature resistance of around 500℃, and are resistant to weathering. Salt fog has a higher pleading. Different temperature-resistant coatings require the correct choice of resins, temperature-resistant pigments and temperature-resistant fillers, and also require different pre-treatments for materials, such as iron-based phosphating, sandblasting, Plating etc.