Polyaddition products which contain uretdione groups

Abstract From the Canadian patent

The present invention teaches a novel polyisocyanate lacquer binder and a method of preparing it. The binder is prepared by reacting uretdione containing polyisocyanates optionally mixed with uretdione fee diisocyanates with water or with low molecular weight compounds which have two alcoholic hydroxyl groups per molecule. Optionally these compounds may be mixed with up to 60 wt.% based on the total weight of hydroxyl bearing compounds, of low molecular weight compounds with one active alcoholic hydroxyl group per molecule. The proportion of, reactants is so selected that the binder produced has from 5 to 20 wt.% of latent isocyanate groups in the form of unopened uretdione rings. The …