The present invention relates to aqueous multistage polymer dispersions obtainable by free-radically initiated aqueous emulsion polymerization, having a soft phase and a hard phase, and a hard-to-soft stage ratio of 25% to 95% by weight to 75% to 5% by weight, the glass transition temperature (Tg) of the soft phase, as first stage, being −30 to 0° C. and that of the hard phase, as second stage, being 20 to 60° C., comprising at least one monomer of the general formula I in which the variables have the following definitions: n=0 to 2, R1, R2, R3=independently of one another hydrogen or methyl group, X=O or NH, Y=H, alkali metal or NH4, to processes for preparing these aqueous polymer dispersions, and to the use thereof as binders in coatings, and also to coatings comprising the polymer dispersion of the invention.