Patent ID: 6927254
Filing Date: 2005-08-09
Classification: C08G

Abstract:
1. An aqueous coating system comprising a) at least one non-aqueous component comprising a water-dispersible polyurethane resin obtained by reacting A1) at least one polycarbonate polyol with a number average molecular weight of from 400 to 6000 Da, A2) optionally, a polyester polyol which is different from component (A1) with a number-average molecular weight M A3) optionally, a low molecular weight compound containing two or more hydroxy and/or amino groups having a molecular weight of from 60 to 400 Da, A4) optionally, a compound which is monofunctional in terms of reaction with NCO groups or which contains active hydrogen atoms differing in reactivity, these units being located in each case at the chain end of a polymer containing urethane groups, A5) at least one compound containing at least two isocyanate-reactive groups and at least one group capable of forming anions, and A6) one or more polyisocyanates,  the resultant polyurethane resin containing from 5.8% to 20.0% by weight of incorporated carbonate groups —O(C═O)O— and being present in a solvent which is inert towards isocyanate groups, b) one or more aqueous binder components comprising at least one hydroxyl-free polyurethane dispersion, c) optionally, auxiliaries and additives and d) at least one crosslinker component.