Curable polyurethane polymer

The present invention relates to a curable polyurethane polymer whichA) from 10 to 60% by weight of at least one hydroxyl-containing prepolymer having at least one α, β-ethylenically unsaturated double bond,B) 0.1 to 30% by weight of at least one compound having at least one isocyanate-reactive hydroxyl and / or primary or secondary amino group and additionally at least one polar functional group per molecule,C) 0.1 to 30% by weight of at least one compound selected from diamines, polyamines and mixtures thereof,D) 0 to 10 wt .-% of at least one other of A), B), C) and E) different compound having at least two isocyanate-reactive groups, which are hydroxyl groups and mixtures of hydroxyl groups with primary and / or secondary amino groups These,E) 0 to 20% by weight of at least one compound having an isocyanate-reactive group,F) 10 to 65% by weight, based on the total weight of components A) to F), of at least one compound having at least two isocyanate groups, polymerized, and the salts thereof, characterized in that the ratio of isocyanate group equivalents of component F) to equivalents of isocyanate-reactive groups of components A) to E) in a range from 0.4: 1 to 0, 9: 1, polymer dispersions containing at least one such polymer and their use.