Cleanability of Aircraft Polyurethane Topcoats.
Phase rept. Oct-Dec 87,
NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA
Pagination or Media Count:
U.S. Navy operational tactical aircraft are painted with a camouflage, two component, aliphatic polyurethane which is the product of hexamethylene diisocyanate and a polyester polyol. This material conforms to military specification MIL-C-83286. One deficiency of this coating which is frequently reported by field activities is its poor cleanability. Navy aircraft are repainted approximately every 3 to 4 years. During their deployment, they are soiled constantly and cleaned approximately every two weeks. The gray lusterless topcoats used in the camouflage schemes often cannot be restored to their original color, even with standard aircraft cleaners. In addition, when the discolored topcoat is damaged and must be repaired, matching of the color is impossible for field touch-up. A test to evaluate coating cleanability has been utilized to determine the severity of this problem and recommend possible solutions. Several coatings on the MII-C-83286 qualified products list were evaluated along with topcoats which contain polymer bead pigments. A distinct correlation was found between cleanability and 60 deg gloss. Topcoats with a gloss of less than 4 had significant color changes when soiled and cleaned coatings with gloss values above 4 had color changes that were far less noticeable even after 10 soilingcleaning cycles. Keywords Polyurethane, Topcoat, Cleanability.
- Coatings, Colorants and Finishes