| abstract |
Polyaddition compounds which are solid below 40 ° C. and liquid above 125 ° C. and contain free isocyanate groups of 0 to 2% by weight, uretdione groups 3 to 16% by weight, urethane groups 10 to 22% by weight and carboxylic acid ester groups from 0 to 20% by weight and a content of carbonate groups from 0 to 25% by weight, the total content of carboxylic acid ester and carbonate groups being at least 1% by weight, a process for the preparation of these polyaddition compounds by reacting polyisocyanates containing uretdione groups , optionally with the use of other diisocyanates, with diols containing ester groups and / or carbonate groups, optionally with the use of diols free of ester groups and carbonate groups and / or compounds which are monofunctional with respect to isocyanate groups, while maintaining an equivalent ratio of 1.2: 1 to 0.6 : 1 and the use of polyaddition compounds for the production of polyurethane plastics , in particular as a crosslinker in heat-crosslinkable two-component polyurethane powder coatings. |