The U.S. Army and Marine Corps utilizes polyurethane coatings as a camouflage topcoat on all Army and Marine Corps tactical vehicles and aircraft. These coatings not only serve to camouflage vehicles but also serve as a protective coating against chemical warfare agents. The coatings must retain their physical properties over a broad temperature range in widely varying climatic environments. Traditionally, these coatings are comprised of a two-component solvent-based polyurethane. However, in an effort to meet current and anticipated EPA regulations as well as military requirements, the Army Research Lab, Weapons and Materials Research Directorate at APG, MD., has developed and patented (U.S. Patent #5,691,410) a water-reducible, two component polyurethane topcoat for military vehicles and aircraft that exhibits a 50% reduction in VOCs compared to the solvent based system. The water-reducible (WR) CARC utilizes hydroxyl-functional polyurethane dispersions and water-dispersible polyisocyanates. The WR polyurethane maintains the required chemical agent resistance and it provides improved weather durability, flexibility and mar resistance. This paper will discuss the ongoing formulation and performance aspects of the WR CARC, and the DOD unique research efforts directed toward pollution prevention and implementing this material to the services.
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