POWDER COATING GUIDE
Information provided by the Powder Coating Institute and the Powder Coating Finisher's Handbook. Additional information regarding powder coating can be found on their website at www.powdercoating.org .
Recent research and testing has developed specially formulated polyester powders that provide even greater weatherability than achievable in previous years, and showing greater success in long-term Florida exposure testing. TGIC-based powders are being used on outdoor stadium seating and other exterior applications that were previously susceptible to degradation from ultraviolet rays. Light poles, lawn furniture, shopping carts, and shelving often benefit from powder with polytetrafluoroethylene (Teflon) additives for increased resistance to abrasion.
Electroconductive & Electrodissipative
Makes of electronic components sometimes use electroconductive and electrodissipative powder coatings, which provide electrostatic discharge protection of the components, critical during the manufacture, testing and transport of electronic goods. The most common colors for these special powders are black and charcoal, but lighter colors are also available.
In recent years, ongoing research and development has been devoted to formulating powders that can cure at lower temperatures, below 212ºF (100ºC), without compromising durability or quality. These powders can be used on temperature-sensitive materials as well as on massive parts that require enormous amounts of energy with other curing systems. More wood materials such as particle board and fiberboard now can benefit from a powder coated finish. This technology has helped to penetrate markets for office furniture, kitchen cabinets, and ready-to-assemble furniture for homeowners.
In addition to successfully penetrating the medium density fiberboard (MDF) market, successful testing has occurred on hardwoods such as beech, oak, ash, and walnut. Research is also being conducted on countertops, wood molding and trim, laminated flooring, and particle board.
Powder has proven to be an effective finishing choice for other heat-sensitive substrates such as plastic parts made of nylon and polycarbonate. In addition, assembled or partially assembled products such as appliances, electric motors, automotive radiators, shock absorbers, foam core doors, and other products that may have plastics, laminations, electrical wires, or rubber seals, can now also receive a powder coated finish. Heat-sensitive alloys such as magnesium can also be powder coating. An powder coating is used to color or frost glass products such as bottles or light bulbs.
Hygienic Powder Coatings
Antibacterial and antimicrobial powders can help prevent the spread of bacteria and germs on products in homes, hospitals, restaurants, and food processing plants.
High Temperature Resistant Powders
Silicone-based powder coatings are often used on products that are subjected to prolonged periods of high heat, up to 1,000ºF (540ºC), and hold their color, gloss, and adhesion. Some of these products include gas and charcoal grills, fireplace inserts, engine exhaust components, and lighting fixtures.
Powder manufacturers are developing more powders for use in thin-film applications that may range from 0.8 to 1.2 mils. These powders offer more with less – better powder penetration into recesses, more film thickness control, and more effective first-pass transfer efficiency, with darker colors most effective in hiding the substrate underneath.
Specially formulated powders can cure by ultraviolet (UV) radiation in a matter of seconds, which is one way to cure products with heat-sensitive substrates or components. Many wood products have enough moisture content to provide sufficient conductivity, and electrostatic attraction can be increased by pretreating and preheating the wood to promote adhesion.
Other specially formulated powders can be cured in a matter of seconds through near-infrared (IR) technology, due to the extremely high heat-up rate. These powders can even work on some heat-sensitive materials, because the irradiated energy is almost entirely absorbed by the powder coating layer.