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The U.S. Department of Defense has stepped up its campaign against liquid protective coatings with a $1.5 million award to PPG Industries to develop a powder Chemical Agent Resistant Coating for military use.
The grant from DOD's Strategic Environmental Research and Development Program (SERDP) is the second of that magnitude, for that purpose, in six months.
In June, the same program awarded $1.4 million to The Sherwin-Williams Company to lead the development of a Chemical Agent Resistant Coating (CARC) powder topcoat for military vehicles and support equipment.
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Images: Department of Defense |
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The 325th Maintenance Company applies Chemical Agent Resistant Coating at the Al Jubayl Paint Facility in Saudi Arabia. DOD has studied the effects of the coatings used during the Gulf War.
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SERDP's mission is to harness the latest science and technology to improve the Defense Department's environmental performance and sustainability. The program partners with the Department of Energy and the Environmental Protection Agency.
CARC Controversy
The Army developed CARCs in 1974 and, beginning in 1983, required their use for all combat and support vehicles and equipment. But the coatings' risks were well known even then.
"Accidents from the handling, storage, and application of chemical agent resistant coating (CARC) operations are numerous and can occur at any level, from organization through IMDS/IM3S (depot) level maintenance," warned a DOD safety pamphlet from 1985.
In 2000, a DOD Environmental Exposure Report examined the risks of CARC used during the Gulf War of 1990-91. SERDP says the two-component polyurethane coatings emit about 5.2 million pounds of organic solvents each year, endangering both workers and the environment.
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In 2000, the U.S. Army's Preventive Maintenance Monthly offered advice on safe handling of CARCs.
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Nevertheless, the coatings still make up the largest category of paints applied to the U.S. military’s inventory of equipment.
Powder Progress?
Now, DOD's stated goal is to develop a zero-VOC, zero-HAP exterior topcoat to replace the military’s current generation of liquid-applied CARC topcoats.
SERDP says powder coatings "are safer to apply than many liquid alternatives, with no emissions of volatile organic compounds (VOCs) or hazardous air pollutants (HAPs). Plus, the ability to reuse overspray yields a nearly 100 percent utilization rate, so they generate little or no waste."
On the other hand, today's liquid CARCs do not absorb chemical agents on the battlefield and require minimal repainting. Most chemical contamination can simply be hosed off, DOD reports.
Any new powder topcoat also must be compatible with pretreatment and primer products already developed and approved for CARC applications. And it must meet military standards for ultraviolet (UV) durability, matte finish, and resistance to chemical agents.
Finding a replacement, therefore, is a tall order.
"To date, no coatings manufacturer has been able to develop a CARC powder topcoat that achieves this required combination of properties using standard powder formulation techniques," PPG notes.
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A UH-60 Blackhawk helicopter gets an olive-drab Water Dispersible CARC finish at Fort Hood, TX. A satisfactory powder topcoat alternative has not yet been invented.
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However, the Pittsburgh-based coating maker thinks it can change that.
PPG's Role
PPG notes that it is already qualified by the U.S. Army Research Laboratory (ARL) as a producer of powder primer for CARC systems. ARL is DOD’s approving authority for all CARCs and, as such, leads research and development activity for CARC systems.
The new grant will enable PPG to continue the ARL collaboration to develop a powder topcoat.
“PPG has developed proprietary processing and resin-synthesis capabilities for powder coatings that we believe will support development of powder CARCs meeting the MIL-PRF-32348 specification,” said PPG Senior Scientist Lawrence Fitzgerald. He said the project would leverage powder coating technology that earned PPG an R&D 100 Award in 2009.
"Combining PPG's coatings expertise with the critical design requirements of the U.S. Army makes this partnership ideal," said John Escarsega, who leads ARL’s Organic Coatings Team within its Weapons and Materials Research Directorate. He is also DOD's commodities manager for CARCs.
"Developing a CARC powder topcoat would benefit both DOD and commercial enterprises because of inherent program environmental health and safety standards,” Escarsega said.
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