The Department of Defense currently spends millions of dollars each year to procure, use, and dispose of toxic and hazardous materials associated with the use of solvent-borne corrosion-protection coatings. Powder coatings have the potential to eliminate more than 95% of the toxic and hazardous materials used in the production and application of current corrosion-protection coatings. Numerous aircraft parts, weapon systems, and support equipment require corrosion coatings but are made from temperature-sensitive materials such as low-tempered aluminum. No commercial powder coatings are presently available that can be applied to these substrates at temperatures low enough to avoid compromising their structural performance.
The objective of this project was to identify and develop powder coating resins for corrosion-protection of temperature-sensitive weapon system components.
A full systems approach was employed to develop novel chemistries, formulate powder coating materials, and develop field repair techniques. Innovations lay in the design of low-temperature cure chemistries and catalysts in addition to weatherable resins. The approach involved exploring experimental and commercial resins, including self-catalyzed systems. Novel photo-rearranging molecules that are self-protecting upon ultraviolet light exposure were investigated. State-of-the-art technologies and refined techniques, such as dielectric cure analysis, were employed to assess the powder cure process and reaction kinetics.
This project increased the number of applications that can benefit from powder coating by developing materials that cure at low temperatures, which protect heat-sensitive substrates. By protecting substrates with powder coatings rather than conventional solvent-borne coating systems, volatile organic compound (VOC) and hazardous air pollutant emissions can be reduced by an estimated 95% per application. Powder coating systems also eliminate the need for a chromated primer. Low temperature cure powder coatings have transitioned to the Environmental Security Technology Certification Program (ESTCP) for full-scale demonstration and validation (WP-200614).
Development of a low-temperature cure powder coating technology will improve the manufacturability, use, and repair of temperature-sensitive, coating-protected components on weapons, aircraft, and auxiliary equipment. Additionally, the elimination of toxic chemicals and VOCs along with the reduction of hazardous wastes will minimize risks to human health and the environment, while also delivering considerable cost savings through avoidance of fines for non-compliance to federal, state, and local mandates. A typical powder coating resin has the potential to reduce labor and material costs by a factor of 10 or more, while total wastes and VOCs can be reduced by a factor of 100 or more. (Project Completed - 2005)