What Is Powder Coating?

Powder coating is a solid powdery synthetic resin coating composed of solid resin and pigments, fillers and additives. Unlike ordinary solvent-based paints and water-based paints, its dispersion medium is not solvent and water, but air. It has the characteristics of no solvent pollution, 100% film formation and low energy consumption. Powder coatings are divided into two categories: thermoplastic and thermosetting. Thermoplastic powder coatings have poor film appearance (gloss and leveling), and poor adhesion to metals, so they are rarely used in the automotive coating field. Automotive coatings generally use thermosetting powder coatings, which are Thermosetting synthetic resin is used as the film-forming material. The resin is first melted during the drying process, and then chemically cross-linked and cured into a flat and hard coating film.Thermosetting powder coating refers to the use of thermosetting resin as the film-forming substance, and the curing agent for crosslinking reaction can be heated to form an insoluble and infusible hard coating. No matter how high the temperature is, the coating will not soften like a thermoplastic coating, but can only decompose. Because the resin used in thermosetting powder coatings is a prepolymer with a lower degree of polymerization and a lower molecular weight, the coating has better leveling properties and better decoration. Moreover, after the low molecular weight prepolymer is cured, It can form network cross-linked macromolecules, so the coating has better corrosion resistance and mechanical properties. Therefore, the development of thermosetting powder coatings is particularly rapid.

   The coating is made of a special resin, pigments, fillers, curing agents and other additives, mixed in a certain proportion, and then prepared by processes such as hot extrusion, crushing and sieving. They are stable in storage at room temperature. After electrostatic spraying, friction spraying (thermosetting method) or fluidized bed dip coating (thermoplastic method), they are heated and baked to melt and solidify to form a smooth and bright permanent coating film to achieve decoration. And the purpose of anti-corrosion.