A process for preparing an aqueous polymer dispersion, the process including forming a copolymer A from at least one α,β-monoethylenically unsaturated C3 to C6 monocarboxylic acid (monomers A1) and at least one other monoethylenically unsaturated compound (monomers A2); reacting the copolymer A with a metal compound M in an aqueous medium; and conducting free-radical polymerization of at least one ethylenically unsaturated compound (monomer P) in the presence of the copolymer A in an aqueous medium.