Abstract: An aqueous copolymer dispersion is obtained by emulsion polymerization of a monomer mixture comprising, as main monomers, 10 to 35 weight % of ethylene, 30 to 60 weight % of a vinyl ester of a carboxylic acid having 1 to 9 carbon atoms and 15 to 50 weight % of a vinyl ester of a branched carboxylic acid having 3 to 15 carbon atoms. The monomer mixture also contains 0.1 to 10 weight % of an ethylenically unsaturated monocarboxylic or dicarboxylic acid having 3 to 4 carbon atoms and 0.1 to 10 weight % of a methacrylic or acrylic acid ester modified with epoxide groups and/or hydroxyl groups. The dispersion is stabilized with 0.02 to 2 weight % of a protective colloid, 0.01 to 5 weight % of a non-ionic surfactant and 0.01 to 5 weight % of an anionic surfactant. All weight percentages are based on the total weight of the main monomers.