PULVERLACK UND SEINE VERWENDUNG

摘要

A coating powder (I) for the prodn. of non-yellowing elastic coatings comprises (A) a polyisocyanate-based binder mixt. which is solid at below 30 degrees C and liq. at above 120 degrees C, and opt. (B) catalysts for the NCO/OH reaction and (C) usual coating powder additives. Component (A) is prepd. from (A1) a polyisocyanate component with a NCO content of 5.0-23 wt.% and a mean NCO functionality of at least 2.1, which contains less than 0.5 wt.% monomeric di-isocyanates with mol. wts. of less than 300 and consists of polyisocyanate(s) as used in paint, with free NCO gps. on prim. and/or sec. C atoms, and (A2) a polyol component consisting of polyhydroxy-polyurethane(s), -polyacrylate(s) and/or -polyester(s) with an OH no. of 30-200 and with at least 50% of the OH gps. on sec. or tert. C atoms, by mixing (A1) and (A2) with a NCO:OH equiv. ratio of (0.6:1)-(1.2:1) and opt. heating for a short time.