Battle for CARC Powder Coating

One of Beth Ann Pearson’s tasks as national product line manager for military coatings at Sherwin-Williams’ Product Finishes Division may be the most daunting of her career.

The company was awarded a $1.4 million research grant by the Department of Defense in June 2012 to develop a zero-volatile organic compound (VOC), zero-hazardous air pollutant (HAP) exterior topcoat to replace the military’s current generation of liquid-applied chemical agent resistant coatings (CARCs) by 2015.

“It’s a very challenging project,” says Pearson, a chemist by training who joined Sherwin-Williams in 2010 with almost two decades of experience in the coatings industry.

It’s also an extremely important project for the U.S. military as it seeks to protect service personnel from chemical attacks, as well as a game-changer for the U.S. powder coating industry.

Moving to Powder

“We are extremely interested in utilizing powder coating for a CARC application,” says Adam Goldstein, vice president of Consolidated Coating in Bellingham, Mass., which specializes in coating a variety of plastic and metal substrates, including military components. “Our company is constantly looking for innovation and new technologies that will simultaneously reduce our VOC emissions, while also increasing our production efficiency. A move to a powder coat CARC would fit both of these categories.”

Pearson’s research team knows that it must match coating durability with safety of troops.

“Far and above everything else, the most important asset that we need to protect is that of our armed forces personnel in the field of battle,” Pearson says. “We—as is the entire coatings industry—are being challenged to consistently improve CARC coatings capabilities.”

Military regulations require all tactical equipment, including ground support equipment, tactical wheeled vehicles and aircraft, to be hardened against the effects of both chemical warfare agents, and degradation caused by the cleaning and decontamination procedures necessary in the aftermath of a chemical attack. These regulations also are followed by the Marine Corps and apply to Air Force vehicles and equipment procured through the Army.

There currently are no commercially available powder coatings that meet the military’s specification MIL-PRF-32348 for powder coating using the camouflage CARC systems, Type III, Class I & II.

With the U.S. EPA breathing down its back, the DoD is under the gun to get more environmentally friendly coatings into its system. Current liquid-applied CARC topcoats supplied by coatings vendors emit about 5.2 million lbs per year of VOCs and HAPs.

The agency turned to Sherwin-Williams, which has lowered VOC emissions in commercialized water-dispersible CARC topcoats from 3.5 lb/gal in solvent-borne CARC to 1.8 lb/gal in water-dispersible CARC. The company also was the first to release a zero-VOC epoxy primer qualified to the MIL-DTL-53022 Type IV specification.

A Collaborative Effort

The research is being led by Sherwin-Williams’ A.W. Steudel Technical Laboratory in Chicago, but scientists from its other powder manufacturing facilities, such as one in Grove City, Ohio, also are involved. The overall research team is a highly specialized group of partners from industry, academia and government agencies, including the Army Research Laboratory and the Naval Research Laboratory. In order to maximize this team research approach, technical collaboration sessions, review meetings and standard reports are the protocol.

“We are the primary research and organization leader, but it is a collaborative effort among the partners in order to maximize the information gained, create processes that advance our goals as efficiently and effectively as possible, and ensure communication and shared knowledge,” Pearson says. “Each partner has a specialized skill or experience that they bring to the team.”

CARC finishes must resist chemical attack from harsh cleaning agents used to decontaminate military vehicles so that the vehicles can be reused post-cleaning without fear of continued contamination and with the assurance that the finish is still fit to resist future chemical agent attacks.

“The true challenge is the combination of maintaining the low gloss necessary for the integrity of the military specification and the IR signature of each color, while also passing the live agent test required for CARCs,” Pearson says.

Enhanced Corrosion Resistance

The Army first developed CARC coatings in 1974, and in 1983 it required all combat, tactical wheeled vehicles, aircraft and essential ground support equipment be painted with the coatings.

The new powder coating spec called for enhanced corrosion resistance for Types I (primer with CARC finish coatings) and II (interior only, primer or topcoat) at 1,500 hrs salt spray and 60 cycles corrosion resistance. The Type III CARC finish coating was divided into Class I for no maximum temperature of the substrate during cure and Class II for a maximum substrate temperature of 350^oF during cure.

Besides resisting chemical warfare agents, the powder coating must meet color and IR requirements, impart low gloss and low sheen specularly, withstand UV degradation in both outdoor and accelerated chamber evaluations, and resist decontamination solutions.

Combining these characteristics into one powder coating is not an easy task, but Pearson believes her research teams in Ohio and Illinois can pull it off.

“We have assembled a great team,” she says. “We are working strategically to fulfill the protocol that was outlined in the research strategy developed by the team in order to successfully develop a CARC powder topcoat within the three-year time frame set forth in 2012.”

Studies & Testing

Because of the scope of the project, it has been broken down into several phases. During the first phase, Sherwin-Williams is working with its partners from industry, academia and government to develop a project plan to fulfill the requirements outlined in the Broad Agency Announcement (BAA) that defines the Strategic Environmental Research and Development Program award.

“Together, the team has also created a variety of new polymers and formulated them into coatings,” Pearson says. “We have also initiated surface analysis studies to assist us in understanding structure and property performance unique to CARC powder.”

The trick will be finding the right formulations to meet color and IR needs, contamination resistance, and corrosion requirements, all at the same time.

“Because this is a new technology, there will be rigorous durability and compatibility testing that must be passed in order to ensure that the product properties are not affected under extreme conditions,” she says.

With the 2015 due date looming, the Sherwin-Williams team is planning to spend the next two years continuing its research and collaborating with its colleagues on the project.

“The team will continue to investigate and build upon information learned in the first phase to narrow the candidate polymers,” Pearson says. “There are gates that we have identified throughout the development process, which are intended as checkpoints to confirm we have met the specified criteria and to ensure each phase builds upon the previous and advances our efforts towards the ultimate development of CARC powder.”

Pearson says this process also will help the team to better understand the coatings’ chemistry and interaction between the system layers.

New Technology is Needed

According to Pearson, developing the right powder coating is a necessity because, as she has stated at several conferences in the past year, current CARC technology will be extinct in 2-5 years.

“The technology has not had a significant advancement since the advent of water-reducible coatings,” she says. “As suppliers to the Department of Defense, we are constantly being challenged to derive new technologies or improved technologies that are more environmentally friendly, offer superior performance such as durability, or bring to market other advantages such as in application or cost savings.”

The final research should help the powder coating industry get an even bigger foothold into military coatings sector.

Shop executives like Goldstein—who has 43,500 sq ft of finishing space, five overhead conveyor lines, two clean rooms, 14 spray booths and a full-service pad printing and silk screening department—say getting a CARC powder coating would lead to additional opportunities.

“I anticipate this technology will provide many benefits to the entire contracting chain,” he says. “The powder coat CARC should allow for higher throughput on our lines, reduce our material cost and eliminate our CARC VOC emissions in its entirety.”

Goldstein says all of these benefits combined will allow a shop like Consolidated Coating to offer cost savings and shortened lead time to any defense contractors who choose to utilize a CARC powder coat.

“This will have a positive effect for job shops and manufacturers all the way up to OEMs and prime contractors,” he says. “Most importantly, this technology will add to the ever-growing need to ‘go green’ and be more environmentally friendly.”

Pearson, who serves as the bridge between the technical/research and the sales/marketing teams at The Sherwin-Williams Company, is happy to fill the role of the face of the company’s military group to the government entities and the coatings industry.

“I have had significant interactions with both industry leaders and customers, and this helps me understand what the industry needs so I can bring those needs to the attention of those who manage the technology requirements,” she says. “Ultimately, this CARC powder topcoat project is being conducted as a team effort, but I am very proud to have the opportunity to help promote the collective strong history of technical strengths and innovations.”

For more information on Sherwin-Williams, please visit sherwinmilitary.com. For information on Consolidated Coating, please visit consolidatedcoating.com.

PPG

The Sherwin-Williams Company