| abstract |
The present invention relates to an aqueous polyurethane coating composition comprising: 1) 1 to 99 wt. % of the reaction product of: a) a polyol component, which is soluble or dispersible in water and is the reaction product of a polyisocyanate component containing 50 to 100 wt. % of an aliphatic diisocyanate, a polyol component containing one or more polyether polyols and having an OH number of 25 to 350 mg KOH/g solids and an isocyanate-reactive component containing at least one group capable of salt formation; and b) polyisocyanate component, which is soluble or dispersible in water, has blocked isocyanate groups and is the reaction product of one or more polyisocyanates having an isocyanurate group content of 0 to 30 wt. %, a reversible, mono functional blocking agent for isocyanate groups, a nonionic hydrophilic component and a stabilizing component which has 1 to 2 hydrazide groups and a molecular weight of 74 to 300 g/mol; and 2) 1 to 99 wt.% of an aqueous polyurethane dispersion prepared from at least one polycarbonate polyol, wherein the total wt. % of components 1) and 2) add up to 100%. |