Patent ID: 6376602
Filing Date: 2002-04-23
Classification: C08G

Abstract:
A water-borne coating composition containing a binder which comprises a mixture of(a) a polyol component which is dispersed in water or a water/solvent mixture and comprises at least one polymer prepared by the emulsion polymerization of olefinically unsaturated monomers and having a molecular weight (Mn) of 500 to 100,000, at least two alcoholic hydroxyl groups per molecule, a hydroxyl value of 15 to 250 mg KOH/g, an acid value of 0 to 7 mg KOH/g, and a total content of sulfonate and carboxylate groups of 0 to 4.5 milliequivalents per 100 g of solid resin and (b) a polyisocyanate component which is emulsified in the dispersion of polyol component (a), has a viscosity at 23Â° C. of 50 to 10,000 mPaÂ·s and an average NCO functionality of 1.8 to 4.2, and contains 12.0 to 21.5% by weight of (cyclo)aliphatically bound isocyanate groups and 2 to 20% by weight of ethylene oxide units present within polyether chains, the polyether chains containing an average of 5 to 70 ethylene oxide units, wherein the components are present in quantities corresponding to an equivalent ratio of isocyanate groups of component (b) to alcoholic hydroxyl groups of component (a) of 0.2:1 to 5:1.