Abstract: Aqueous polymer dispersions containing,I as the disperse phase, a film-forming dispersion polymer andII in the aqueous phase, from 5 to 40% by weight, based on the total dry mass of I and II, of a completely or partially neutralized water-soluble copolymer ofa) from 50 to 80 mol % of an olefinically unsaturated mono- or dicarboxylic acid, of an anhydride of these acids or of a mixture of these monomers,b) from 20 to 50 mol % of a C.sub.3 -C.sub.12 -alkene, of styrene or of a mixture of these monomers andc) from 0 to 10 mol % of further monomers which can be subjected to free radical polymerization,and the powders obtained by spray-drying these polymer dispersions are suitable as binders for water-resistant plastics renders and coatings and as adhesives or adhesive components.