Powder Paint and Coating

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Customers today demand higher quality and durability from the products they buy. Not only do they expect these products to perform well, but they want the finish to look good and resist corrosion for a much longer period of time. Powder coating is different from painting. There are no liquids or solvents. Therefore, it is the ultimate coating for environmental friendliness. Being dry, the powder overspray can be reclaimed for very high application efficiency. It uses heat to convert its state from a powder to a continuous film. The powder coating materials are basically plastics that have been ground into a fine powder. The coating powder is formulated with plastic resins, pigments, flow agents and other special ingredients to provide the desired characteristics of the coating film. There are two basic classifications of powder coating materials. They are "thermoplastic" and "thermoset" powders. Thermoplastic powders are generally applied to a surface that has been preheated to a temperature significantly higher than the melting point of the powder. As a thermoplastic powder, material is applied to the hot surface it will melt and "fusion bond" to the surface and then "flow out" into a strong, continuous film. As the film cools it develops its physical properties. Nylon powder coating materials are the most commonly used thermoplastic powders. Thermoplastic coatings are known for their wear and chemical resistance. Thermoset powders contain a heat-activated catalyst and are generally applied to a surface at ambient temperature. The surface and the powder are then heated and as the temperature rises past the melt temperature of the powder (normally 250�-275�F) it will melt and "fusion bond" to the surface. As the temperature continues to rise (normally 360�-380�F) a heat sensitive catalyst becomes active and causes the molecular structure of the plastic material to change or "cross-link." The temperature is maintained while the coating material cures and forms a...
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