About heat-resistant epoxy powder coatings

Heat-resistant powder coating refers to a protective powder coating that can withstand high temperatures above 200 °C for a long time, and the coating film does not change color and is not damaged, and can still maintain appropriate physical and mechanical properties. The heat resistance of silicone powder coating is relatively high, but its price is high, the initial appearance and mechanical properties are not very good, the curing temperature is high, and it is quite difficult to obtain a coating film with long-term high temperature resistance of more than 400°. Although the heat resistance of epoxy resin itself is worse than that of silicone resin, its performance is relatively comprehensive; By modifying and adding appropriate curing agents and pigments, good heat resistance can also be obtained. Therefore, heat-resistant epoxy powder coatings are widely used.

1 Performance requirements for heat-resistant epoxy powder coatings

1.1 Heat resistance

Heat resistance is the most important performance index, some products may not be used at a certain high temperature for a long time, therefore, heat resistance can be divided into long-term and short-term two. According to the performance requirements of the object and other aspects, the appropriate modified epoxy resin, curing agent and pigment filler can be selected to achieve the purpose of low price and high quality.

1.2 Mechanical Properties

This includes both initial and late mechanical properties. Due to the limitations in the selection of curing agents and pigments and fillers, their mechanical properties can be slightly reduced compared with the requirements of general powder coatings; However, it is important that the mechanical properties are not reduced too much in the later stage.

1.3 Anti-corrosion properties (including chemical resistance)

The anti-corrosion performance of epoxy resin is relatively good, therefore, epoxy powder coating can fully meet the requirements of this aspect.

1.4 Appearance

Including flatness, gloss, color and other properties. The flatness can vary depending on the object of use. In general, slight orange peel should be allowed. Gloss mostly requires a flat and matte finish, which is completely achievable. As for colors, especially light colors, it is more difficult to keep them the same at all. Antioxidants and hindered amines can be added appropriately to solve the problem.

1.5 Storage stability

Since it is not a high-temperature fast-curing and the Tg of the resin is high, the storage stability should be no problem.

conclusion

There are many varieties of high-temperature resistant polymers, but there are still certain difficulties and problems in preparing powder coatings that can meet the requirements in all aspects. With epoxy resin, after modification and selection of appropriate curing agents and pigments, powder coatings with different high temperature requirements (200~600 °C) can be prepared. Heat-resistant epoxy powder coating can be widely used in household appliances: such as barbecue grills, heaters, high-power lighting, and high-temperature parts of mechanical equipment, such as smoke exhaust pipes, high-temperature furnaces, petrochemical plants, aircraft, missiles, aerospace equipment, etc. Heat-resistant epoxy powder coatings can also be used for the coating of electrical insulating materials. Brominated epoxy resin or appropriate flame retardant can also be used as a flame retardant powder coating.