The versatility in powder coating effects and textures has come about over the past 10 years, changing the look of an appliance from simply a necessary piece of equipment to a focal point that makes a statement. Where liquid coatings once reigned because they could be applied without the heat temperatures necessary for curing powder coatings, thermosetting powders with lower temperature curing methods have helped powder coating expand to substrates beyond metal, including plastics and wood-based products. The result is a protective coating that is functional and decorative.

Graffiti-Free

Greasy hands and Sharpies are no match for Grafaway, a line of graffiti-resistant powder coatings from Rohm and Haas Powder Coatings, Philadelphia.

Originally created for subway and signage applications, this powder coating is finding its way into the home because of the cleanability and color potential.

"One of the old approaches to having both color and cleanability was to put a clear coat over the color so it wouldn't stain," says Steve Kiefer, marketing manager, North American industrial goods for Rohm and Haas. "But it's outrageously expensive to add a second finishing operation. Grafaway requires no second layer of coating."

High scratch resistance and low porosity-absorption characteristics of the film provide permanent protection against damage. Grafaway's color and gloss are unaffected, even if an appliance has been marred with spray paint. The marks are wiped away with a common cleaning agent.

Cool Grills

Rohm and Haas also has a heat-resistant silicone powder coating, ideal for applications such as a stove or barbeque grill. Mor-Temp is available in virtually any color in either a smooth or textured finish. Kiefer says the coating can withstand prolonged service temperature exposure up to 1,000°F.

"Mor-Temp is a whole family of coatings," Kiefer says. "Different temperatures, colors and textures. There is a coating for all different temperatures and length of time for heat resistance."

Reactive Textures

Problems with texture powder coatings have ranged from limited appearance options to difficult application. The Textra line from Rohm and Haas, however, offers a range of texture appearances from very coarse to very fine with good coating application properties.

"In the past, textures were made by adding fillers or plastic substrates to the coating, which resulted in a thicker film coating that was difficult to apply," Kiefer says. With the Textra line, the curing process gives the powder coating its texture properties. Instead of the old way where inert ingredients interrupted the flow to create a texture, with Textra, the ingredients actually react, and by varying the reaction, the coating can achieve different looks.

Magic Act

DuPont Powder Coating's newest lines, Alesta Flare-Illusion and Blaze-Illusion are sparkling, jewel-like color combinations that are weatherable for outdoor appliances, like lawnmowers.

Flare-Illusion is a two-coat system, generally using a high-gloss black base coat and then a topcoat that is available in five different colors: Illusion Amber, Illusion Amethyst, Illusion Emerald, Illusion Lapis and Illusion Aquamarine.

"The topcoat is really a clear coating with a pigment that refracts the light at different angles," says Trena Benson, marketing manager for DuPont. "The wavelength of the reflected light changes continuously."

High-gloss black is not the only option for the base coat. While blacks and darker colors tend to enhance the look by adding depth and richness to the color, Benson says that any color can be used for the base coat, providing an endless array of colors in the two-coat system.

Blaze-Illusion has the sparkle and is affected by the light source, only in a one-coat system. Color options are more limited with only red, purple and black,* but the line is preferable for customers who don't want two stocks of inventory or extra labor costs.

Antiperspirant

PPG Industries, Pittsburgh, will soon have a one-coat metallic powder to market that is perspiration resistant.** The name is not being released yet, but Barry Keating, global product and market manager for PPG's industrial powder coatings division says it's being evaluated by a number of OEMs, including a major life fitness manufacturer and should be available by the end of the year.

"It's a powder urethane metallic that would replace the two-coat system," Keating says. "There is an increased desire for new effects and styling, starting with metallic products. The appliance industry, especially washing machines and dryers, are moving to different metallic looks to create pretty upscale machines."

Keating says the challenge is to create one-coat metallics that will meet or exceed chemical type resistance requirements. He says the company has worked on different processes to solve the challenges of passing chemical resistance testing in the making of this powder.

Cured

PPG has begun marketing a low cure powder called XLC, able to cure down at 220°F, giving the consumers electronics industry the opportunity to use alternative substrates, specifically plastics.

"This gives OEMs a chance to replace some traditional metal parts, like back panels, with plastics," Keating says.

The low cure powder can be metallic or different textures, in virtually any color. The new powder is currently being used on some metal and wood parts.

Greg Bocchi, executive director of The Powder Coating Institute, says the future of powder coating will include lower temperature curing. "Powders will continue to offer lower temperature cure methods for expansion into more heat sensitive substrates," Bocchi says. "Also, better clear coats are coming, and metallic powder coatings that offer more depth of a finish." He adds that quick color change methods also will become available.***

Notes:

*A follow up with DuPont's Benson reveals that its Blaze-Illusion now also is offered in aquamarine and amethyst, too.

**A follow up with PPG's Keating reveals that both the one-coat metallic and low cure are available commercially today.

***A follow up with PCI reveals that quick color change methods currently are available, with ongoing technology to improve the speed and ease of color change.