MAT POLYURETHANE POWDER COATING MATERIAL AND ITS USE FOR APPLYING TO HEAT-RESISTANT SUPPORT

摘要

Coating powder for the production of matt coatings contains: (A) a hydroxyl group-containing binder with an OH number of 25-200 and a mol. wt. of 400-10000, which is solid at below 40 degrees C and liquid at above 130 degrees C; (B) aliphatic and/or cycloaliphatic polyisocyanate(s) with blocked and possibly free isocyanate (NCO) groups, which is solid at below 40 degrees C and liquid at above 125 degrees C; (C) a carboxylic acid and/or anhydride group- containing component which is solid at below 40 degrees C and liquid at above 160 degrees C, comprising (C1) aliphatic and/or cycloaliphatic 4-20C dicarboxylic acids, (C2) monomeric and/or polymeric, optionally modified anhydrides of diacids (C1), and/or (C3) 4-18C aliphatic hydroxy-acids; (D) a component with a mol. wt. of 200- 5000, containing groups which are reactive towards carboxylic acid and/or anhydride groups; and optionally (E) additives etc. as used in coating powders. The amounts of (A)-(D) are such as to provide 0.6-1.4 NCO groups (from B; blocked and free NCO) to each OH group in (A) and 0.3-1.5 reactive groups from (D) to each COOH equiv. in (C), and the content of components (C and D) is 10-40 wt% based on (A + B + C + D).