PPG Lands DOD Coating Funds


PPG Industries has received more than $1 million to develop military-grade coatings that do not include health-damaging isocyanates.

The U.S. Department of Defense Strategic Environmental Research and Development Program (SERDP) awarded $1.071 million to PPG Industries' Coatings Innovation Center in Allison Park, PA, to help develop non-isocyanate liquid coatings that meet military specifications.

Commonly used in paints and coatings, isocyanates are powerful irritants to the mucous membranes of the eyes and gastrointestinal and respiratory tracts, according to the Centers for Disease Control and Prevention.

"Direct skin contact can also cause marked inflammation," CDC reports. "Isocyanates can also sensitize workers, making them subject to severe asthma attacks if they are exposed again. Death from severe asthma in some sensitized subjects has been reported."

Multiple Applications

PPG's new grant will support the development of coatings that can be applied in the industrial, protective and marine, and automotive refinish coatings markets.

"The chemical-agent-resistant coatings used by the armed forces are based on technology that is more than 40 years old,"  Ljiljana Maksimovic, PPG development associate, industrial coatings research, said in a press release about the project.

SERDP is a DOD environmental research program that uses science and technology to improve environmental performance, reduce costs, and enhance and sustain mission capabilities. The program promotes partnerships among academia, industry, the military services, and other federal agencies.

Candidate Chemistries

The objective of the PG project is to develop a high-performing exterior topcoat without the use of diisocyanate compounds. PPG will also investigate alternative reaction chemistries that produce polyurethanes without using diisocyanates and coating formulations that use non-polyurethane resin systems.

SERDP's project description identifies three "candidate chemistries":

Polysiloxane-Based Systems. Polysiloxane coatings result from the hydrolysis and condensation of alkoxy silane-functional polymers.

PPG has developed semi-gloss coatings based on this chemistry, and researchers at the U.S. Army Research Laboratory (ARL) are formulating camouflage chemical agent resistant coatings based on two component siloxane systems, also called hybrid epoxy-siloxane coatings.

Initial hybrid epoxy-silane formulations have demonstrated exceptional protective properties due to their chemical structure, which combines the durability and hardness of epoxy coatings and notably improves on the gloss and color retention of urethane type coatings.  

Military spray painting
Department of Defense

The Department of Defense is trying to develop coatings that are safer for painters and less damaging to the environment. The U.S. military uses about two million gallons of urethane coatings each year.

Polyuretdione-Based Systems. The polyuretdione/hydroxyl reaction results in a urethane linkage, although no free isocyanates are used

Accordingly, coating performance properties are similar to conventional urethanes. Recent catalyst studies conducted by PPG have identified options which provide cure at room temperature, but improvements are needed in polymer design to reduce volatile organic compound (VOC) levels.

Cyclic Carbonate-Amine Based Systems. Cyclic carbonates are another example of non-isocyanate coatings producing a polyurethane linkage during crosslinking.

Cyclic carbonates can be formed from the reaction of epoxides with carbon dioxide (CO2) using a catalyst under slight pressure and temperature. Feasibility of room-temperature cure has been demonstrated by PPG through appropriate catalyst selection or the addition of co-reactants.

Project Partners

PPG has partnered with the Army Research Lab and the U.S. Naval Air Systems Command on the project. As prime contractor, PPG will synthesize, formulate and test coatings that meet polyurethane performance standards but do not include isocyanates.

"Many contain isocyanate materials that can potentially cause skin and respiratory reactions. We'll be working to develop updated formulas that can address new and emerging chemical agent threats," Maksimovic said.

"These new technologies will also help prevent exposure to isocyanates and reduce isocyanate-related health hazards."

DOD coatings programs

Current chemical agent resistant coatings "are based on technology that is more than 40 years old," according to PPG. It is looking at safer options.

Anticipated project completion is in 2016, according to SERDP.

Safer Military Coatings

The U.S. military uses about two million gallons of urethane coatings each year, amounting to over 20,000 pounds of hexamethylene diisocyanate (HDI).

The PPG award is part of DOD's recent push to develop safer, less environmentally damaging coatings.

In January, SERDP awarded $1.5 million to PPG to develop a powder Chemical Agent Resistant Coating (CARC) for military use.

The DOD's goal is to develop a zero-VOC, zero-HAP exterior topcoat to replace the military's current generation of liquid-applied CARC topocoats.

The same program awarded $1.4 million to The Sherwin-Williams Company in June 2012.

CARCs were developed in 1974 and used for all combat and support vehicles and equipment starting in 1983, despite well-known risks. In 2000, a DOD report examined the risks of CARCs used during the Gulf War. The two-component polyurethane coatings emit about 5.2 million pounds of organic solvents each year, endangering workers and the environment, according to SERDP.

The coatings still make up the largest category of paints applied to the U.S. military's equipment.


Tagged categories: Chemical resistance; Coating Materials; Department of Defense (DOD); Funding; Government; Isocyanate; Polyurethane; PPG; Sherwin-Williams

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