Bifunctional polyaddition compounds as crosslinkers for polyurethane powder coatings

Abstract

A polyaddition compound having uretdione and carboxyl groups, and having a melting range of between 40 and 200° C., a free NCO group content of from 0 to 5% by weight and an NCO functionality of at least 1.5, and a number-average molar mass of between 1000 and 10,000, may be prepared by reacting at least one polyisocyanate containing uretdione groups, at least one hydroxycarboxylic or mercaptocarboxylic acid, and one or more of at least one monofunctional compound having a functional group which is reactive toward an isocyanate, at least one aliphatic and/or cycloaliphatic polyol, at least one polyol having functional groups, and at least one aliphatic and/or cycloaliphatic polyamine. Polyurethane plastics, especially polyurethane powder coating materials may be prepared from the polyaddition compound of the present invention.

Dependencies are inferred from the claim text.