Aqueous polymer compositions and their use as coatings are disclosed. A composition includes at least one polyurethane (meth)acrylate A and at least one compound B having a molecular weight of below 1000 g/mol and having at least two ethylenically unsaturated double bonds per molecule. The polyurethane (meth)acrylates A include the following components: component A1 includes at least one polyisocyanate A1a and at least one diisocyanate A1b; component A2 includes at least one compound having at least one ethylenically unsaturated double bond, and at least one functional group F; component A3 includes at least one neutral polyol including at least one aliphatic, polymeric polyol A3a and at least one low molecular weight diol A3b; component A4 includes at least one compound having at least one ionic or ionizable group I′ and at least one functional group F′; and component A5 includes at least one poly-C2-C3 alkylene ether.