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Abstract

Aqueous coating compositions include dispersed polyurethane-vinyl polymer hybrid particles obtained by free-radical polymerization of at least one vinyl monomer in the presence of a polyurethane. The polyurethane and the vinyl polymer in the hybrid particles are present in a weight ratio of polyurethane to vinyl polymer ranging from 1:1 to 20:1, and the polyurethane is the reaction product of at least the following components: (a) from 5 to 40 wt. % of at least one organic difunctional isocyanate, (b) from 0.5 to 4 wt. % of an isocyanate-reactive compound containing ionic or potentially ionic water-dispersing groups having a molecular weight of from 100 to 500 g/mol, (c) from 40 to 80 wt. % of at least one diol having a molecular weight from 500 to 5000, (d) from 0 to 10 wt. % of at least one active-hydrogen chain extending compound with a functionality of at least 2 other than water, (e) from 0 to 10 wt. % of at least one diol having a molecular weight below 500 g/mol. The isocyanate and hydroxy groups on the components used are present in a respective mole ratio (NCO to OH) in the range of from 0.8:1 to 5:1.

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