One of the main advantages is the absence of solvents. In a film applied by liquid technology, with intensive removal of solvents, pores are formed, which cause deterioration of adhesion and premature occurrence of underfilm corrosion.
Powder coating has less shrinkage and less porosity of the film. In powder paints, an expanded range of binders is used due to the use of film-forming agents that are not soluble in solvents, for example, polyethylene, polyamides, fluoroplastics. This makes it possible to obtain inexpensive coatings with high atmospheric and chemical resistance. Powder technology excludes such complex operations as control of paint viscosity and fine-tuning it to the required value. Powder paints are supplied exclusively in dry, ready-to-use form, which provides both savings and greater stability of the quality of the resulting coatings. Significant savings in the cost of solvents are achieved, which in liquid paints only act as carriers for film-forming substances. The amount of solvents in liquid paints and varnishes reaches 50%. Additional savings – reduced energy consumption for solvent evaporation and kiln vapor removal is achieved using very economical bell-type and vertical-conveyor polymerization furnaces.
Using powder coating technology improves the sanitary and hygienic working conditions. The powder coating technology is environmentally friendly. Almost 100% of the consumable material (paint) is transferred to the products. The concentration of volatile substances released from the paint during the polymerization process does not reach the maximum permissible concentration even inside the polymerization ovens.
Significant savings come from shorter curing times due to the high rates of film formation from the melts and because the drying of a single-layer powder coating is carried out once in comparison with repeated drying in the case of multilayer conventional coatings. Powder coating cures in 30 minutes to 30 seconds, depending on the type of paint and how the product is heated. After cooling, the product is ready for use or further processing. It is possible to obtain thick one-coat coatings (due to 100% solids content) instead of the more expensive multilayer coatings in the case of liquid paints. The entire cycle of obtaining a finished powder coating on a product can take less than 30 minutes. Liquid coating forms within hours.
Reducing the cost of maintaining the production area of the powder coating site reaches 90% due to the elimination of air drying (a product coated with powder paint can be placed directly in the oven without exposure to air), a small number of processing stages and a lesser need for storage facilities. An automated powder coating area allows for one hour to paint products with a larger total area than the area occupied by this area. Such efficiency in the use of production areas with liquid painting is unattainable. Due to the high strength of powder coatings, damage to painted products during transportation is minimized, and therefore packaging costs are reduced while maintaining the presentation of the products. Another economic aspect is the increased chemical resistance and physical and mechanical properties of the coatings. Tens of thousands of kilometers of trunk pipelines all over the world are covered with protective powder paints.
The powder coating process has several operational advantages. One of them is easy cleaning of spray equipment. Removing dry powder is much easier than removing layers of liquid paint. The transition time from one paint color to another in a powder coating conveyor line takes from one hour to one shift, and up to 95% of the paint collected during the cleaning process of equipment is recyclable. Powder paint, which did not settle on the product during the application process, is collected in the recuperator, while it does not lose its properties and is reused after sifting and drying. Powder technology is generally characterized by low losses of powder paints (1-2%) in contrast to liquid paints and varnishes (up to 50%). During electrostatic application, the powder tends to be distributed evenly over the flat surfaces of the product and in a slightly thicker layer, which improves the quality of the coating, on sharp corners and edges of the product. The permissible uneven thickness of the applied powder layer, which does not impair the decorative and protective properties of the coating, lies in a very wide range from 20 to 200 microns. No paint drips or wrinkling of the film form, which reduces the requirements for control over the application of powder paints and allows for a fully automated painting process. With manual painting or touch-up, it is possible to easily correct coating defects before curing. If a defect is found, such as adhering lint, the powder is brushed off or blown away with a jet of compressed air and reapplied.
Powder technology is most widely used for painting serial metal products and structures in factory conditions. For example: wheel disks and car bodies, aluminum profiles, furniture frames and fittings, construction fittings, metal tiles, pipes and fittings for water and gas pipelines, machine parts and mechanisms, electric pumps, electrical cabinets, bicycles, utensils and garden tools … Promising directions for use powder coating technologies: agricultural machines and mechanisms, elements of urban underground communications, construction machines, etc.