| 摘要 |
<p>Solid polyurethane powder coating compositions that are curable at low temperatures, comprising: A) at least one uretdione powder coating hardener, based on an aliphatic, (cyclo)aliphatic or cycloaliphatic polyisocyanate and a compound containing hydroxyl groups, having a melting point of 40 to 130.degree.C, a free NCO content of less than 5% by weight and a uretdione content of 6-18% by weight; B) at least one polymer containing a hydroxyl group having a melting point of 40 to 130.degree.C and an OH value between 20 and 200 mg KOH/gram; and C) as a catalyst, at least one quaternary ammonium carboxylate of the formula [NR1R2R3R4]+ [R5COO]- in which R1, R2, R3 and R4 are each alkyl or the like and R5 is H, alkyl or the like. The powder coating compositions may cure at a low temperature without emitting a blocking agent.</p> |
