Above: Internet server cabinets are among the products that can be powder coated.

Functions of powder coatings expand with efficiency gains, environmental compliance

February 2020 - Powder coatings, especially those developed by giants such as PPG, have consistently gained adherents as the manufacturing technology becomes greener, saves steps in processing, limits waste and prevents pollution, and makes products long lasting.

Shelley Verdun, business manager for powder coatings within PPG’s Industrial Coatings division, is a chemist and a 32-year veteran of the 137-year-old Pittsburgh-based company. The division handles various market segments such as electrical equipment and appliances, automotive underbody components, and office furnishings.

One of the first advantages of powder that PPG discusses with potential customers, including coil coaters, is that such coatings offer a low cost of entry to the market, compared with liquid coatings.

Automotive parts such as shocks and springs must be coated for corrosion resistance.

Liquid paint, she says, “takes a lot of labor to clean up after, maintain and then, in terms of energy efficiency, to burn off exhaust. All that is expensive.” Coaters must also follow state and federal rules “to handle that on their applicator lines.”

Powder is 100 percent solid. In liquid, paint is sold in gallons or tanks. Powder sells in blocks or in fiber drums. There is a smaller footprint for powder.

“It’s very user friendly, less variable. There is less training involved to teach its use. There are no solvents, no stickiness. Cleanup is easy, which means less labor,” Verdun says.

In terms of thermal treatment (curing), heating costs are lower because users don’t have to burn off solvents. Because of how it’s applied, the coating line is shorter, and coaters can place parts closer together.

Verdun stresses the benefits of powder over liquid. “When you think of a gallon of paint that an applicator would use, of the entire gallon we sell to a customer, only 60 percent ends up on parts. The paint goes onto the booth, on the floor, into the filter. That’s just the nature of liquid coatings. And there is no way to reclaim the lost paint.

“Powder is a completely different ballgame—it’s up to 99 percent efficient. Any of the powder that is sprayed is recaptured, goes into a tray and is reclaimed,” Verdun says. That loose powder is blended back with virgin material, “so there is very little waste.”

When a new powder line goes up, “compliance is faster, easier and lower cost” than lines that coat with liquid paint, she says.

Racking systems in distribution centers must be resistant to bumps and scrapes and hard wear.

Rust: A four-letter word

Most of PPG’s clients have some type of corrosion specification, according to Verdun. Specs are written for everything from an electrical panel to agricultural equipment. Some customers perform their own corrosion tests. “We perform extensive corrosion testing, numerous hours in salt spray cabinets and cyclical corona testing. That is real world, how parts cycle through various stages—forming, heating, drying, etc.

“Regardless, the technologies are deemed good, better and best,” says Verdun. “At PPG, in terms of functional performance, one of the earliest and best technologies has been electrocoating. Back in the day, you would see cars rusting out. That doesn’t happen now due to electrocoating. However, it doesn’t stand alone. We have done quite a bit of testing in electrocoating and powder. In house, our high-end powder coat technology is the benchmark for corrosion resistance.”

To prevent rust, customers often use two coats of liquid. Others use primer, paint and a topcoat. “That can be expensive but it exhibits extreme performance,” equal to 5,000 hours of salt spray. Some customers also specify zinc undercoating and epoxy primers for greater corrosion protection.

Covering edges

Last April, PPG introduced a new product, the Envirocron Extreme Protection Edge powder coating technology. It serves as an alternative to a two-coat system (primer plus topcoat) and was developed as a result of customer feedback.

PPG asked customers, “What would be the holy grail product?” Verdun says. “They said they want either growth or savings, and both would be great. Envirocron offers one-coat exceptional corrosion performance.”

As manufacturing capabilities and laser cutting improves, material edges provide challenging surfaces for coating to stick to, Verdun explains. “You cannot always see it but an uncoated edge can appear on a finished part, and that is the entry point for corrosion.”

With Envirocron, PPG found a way to get the powder to the edge of the part and getting the powder to stick.  As the part goes into use in the field, there is no entry point for the corrosion.

“Laser cutting is all the rage,” she says, “but some customers and equipment suppliers are looking to edge rounding equipment so part edges are less sharp and coating would stick. They are thinking about adding that step in house, so the paint is better on the edges.”

PPG has seen improvements with edge rounding work well and the user does not need to spend millions of dollars on equipment, training and labor, and time. “Our product stays on the edge and protects the edge,” she says.

Many users believe the coating they use will protect the entire piece. “But a sharp edge may not come out of the curing oven with paint on it. This product also protects workers’ hands. The sharp edges are coated and are therefore less sharp. A lot of workers are moving parts from machine to machine or loading and unloading parts. The safety aspect is an added benefit that we didn’t foresee. So it’s an improvement in the customers’ process,” Verdun says.

Improvement goals

PPG powder coating business pursues innovation. “We want to provide our customers with solutions for end products that delight them, both in terms of responding to their needs and issues and resolving them. How will it save money, improve operations internally, like moving from two coats to one, or reduce cure time.”

The other goal is to develop solutions that help customers improve their own quality and brand image, such as how a coating improves appearance.

“If you would ask anyone what’s the biggest negative, they say it’s in the metallics area, in terms of aesthetics,” says Verdun. “That is what we are working on to improve. We want to innovate and provide value to our customers” while growing powder’s market share and improving its function. MM