The coatings we're generally familiar with are liquid. Have you ever seen powder coating? Powder coating is a new type of coating material with resin as its primary component. It's a 100% solid powder and solvent-free. It's also a solid powder coating that can replace paint. It features no solvents, no pollution, energy and resource savings, reduced labor intensity, and high mechanical strength. This coating can only be applied via electronic spraying, so what are its application types? Below, Xiao Gu explains in detail what powder coating is and its different types!
I. What is Powder Coating?
Powder coating is a solid powdered synthetic resin coating composed of solid resin, pigments, fillers, and additives. Unlike conventional solvent-based and water-based coatings, its dispersion medium is air, not solvent or water. It is solvent-free, has 100% film formation, and consumes very little energy.
II. Types of Powder Coatings
1. Thermosetting
Thermosetting powder coatings use thermosetting resins as film-forming materials. A cross-linking curing agent is added, which, upon heating, forms an insoluble, hard coating. Unlike thermoplastic coatings, these coatings will not soften at high temperatures, but will instead decompose. Because the resins used in thermosetting powder coatings are prepolymers with a low degree of polymerization and a low molecular weight, the coatings exhibit excellent leveling and decorative properties. Furthermore, upon curing, these low-molecular-weight prepolymers form a network of cross-linked macromolecules, resulting in excellent corrosion resistance and mechanical properties. Therefore, thermosetting powder coatings have experienced particularly rapid development.
2. Thermoplastic
Thermoplastic powder coatings first appeared in the 1950s. They melt at the spraying temperature and solidify into a film upon cooling. Due to their simple processing and spraying methods, powder coatings require only heating to melt, leveling, and cooling or extraction to solidify the film, eliminating the need for complex curing equipment. Most of the raw materials used are commercially available polymers, which can meet performance requirements under most conditions. However, they also have certain drawbacks, such as high melting temperatures, low coloration levels, and poor adhesion to metal surfaces. Despite this, commonly used thermoplastic powder coatings still exhibit unique properties. Polyolefin powder coatings offer excellent solvent resistance; polyvinylidene fluoride coatings offer outstanding weather resistance; polyamides offer excellent abrasion resistance; polyvinyl chloride offers a good price-performance ratio; and thermoplastic polyester powder coatings offer attractive appearance and high artistic appeal. These characteristics have led to thermoplastic powder coatings occupying a significant share of the coatings market.
III. Advantages of Powder Coatings
1. Health and Environmental Protection
They eliminate the need for various harmful liquid chemical additives, such as film-forming, dispersing, wetting, leveling, and anti-corrosion and mildew-proofing agents, that are often added to achieve coating performance.
2. Easy Transportation and Storage
Ordinary paints contain approximately 20-50% water or solvents, while powder coatings are completely solid and contain neither water nor solvents, making them easy and safe to transport. Furthermore, paints containing water or solvents often freeze when transported or stored below 0°C; powder coatings do not have this problem.
3. No Preservatives Required
Traditional liquid paints contain both water and food for bacteria, making them susceptible to contamination. Therefore, preservatives are added to prevent deterioration. Latex powder paint, however, is free of bacterial contamination and requires no preservatives.
4. Paint Odor
Compared to traditional paints, this paint dissipates quickly, practically disappearing the moment it's applied.
