Use of hybrid copolymers as protective colloids for preparation of polymers based on ethylenically unsaturated monomers (base polymers) in the form of water-redispersible powders, characterized in that hybrid copolymers are added as a drying aid to base polymers in the form of aqueous dispersions and the mixtures thus obtained are then dried, wherein the hybrid copolymers are obtainable by A) free-radically initiated polymerization of one or more ethylenically unsaturated monomers a) selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate, vinyl esters of alpha-branched monocarboxylic acids having 5 to 13 carbon atoms, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, norbornyl acrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, 2-propylheptyl acrylate, isotridecyl methacrylate, dihydrodicyclopentadienyl acrylate, ethylene, propylene, 1,3-butadiene, styrene, methylstyrene, vinyltoluene, vinyl chloride, 2-dimethylaminoethyl methacrylate, 3-dimethylaminopropyl-methacrylamide, N-(1,1-dimethyl-3-dimethylaminopropyl)-acrylamide, N-(1,1-dimethyl-3-dimethylaminobutyl)-acrylamide, N-(1-methyl-1,3-diphenyl-3-diethylaminopropyl)methacrylamide, 1-vinylimidazole, 1-vinyl-2-methylimidazole, 1-vinyl-2-ethylimidazole, 1-vinyl-2-phenylimidazole, 1-vinyl-2,3-dimethylimidazole, 1-vinyl-2,4,5-trimethylimidazole, diallyldiethylammonium chloride, (3-methacryloyloxy)propyltrimethylammonium chloride, (3-methacryloyloxy)ethyltrimethylammonium chloride, (3-methacrylamido)propyltrimethylammonium chloride, trimethyl-3-(1-acrylamido-1,1-dimethyl-propyl)ammonium chloride, trimethyl-3-(1-acrylamido-1,1-dimethylbutyl)ammonium chloride, dimethylacrylamido-propyl-4-trimethylammoniobutenyl-2-ammonium chloride, 2-acrylamidomethoxy)ethyltrimethylammonium chloride and diallyldimethylammonium chloride, and optionally one or more silanes b) selected from the group of the ethylenically unsaturated silanes and mercaptosilanes in the presence of one or more water-soluble polymers c), using the water-soluble polymers c) in stage A) to an extent of 20% to 95% by weight, based on the total weight of the amount of water-soluble polymers c) and ethylenically unsaturated monomers a) used in the polymerization, and optionally B) condensation of one or more silicon compounds of the general formula n SiR 1 4-n or of one or more condensation products of the formula, where R is an optionally substituted alkyl or aryl radical having 1 to 20 carbon atoms or a hydrogen atom, R 1 is an optionally substituted hydrocarbyl radical or a hydrogen atom, and n assumes a value from 1 to 4. A) free-radically initiated polymerization of one or more ethylenically unsaturated monomers a) selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate, vinyl esters of alpha-branched monocarboxylic acids having 5 to 13 carbon atoms, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, norbornyl acrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, 2-propylheptyl acrylate, isotridecyl methacrylate, dihydrodicyclopentadienyl acrylate, ethylene, propylene, 1,3-butadiene, styrene, methylstyrene, vinyltoluene, vinyl chloride, 2-dimethylaminoethyl methacrylate, 3-dimethylaminopropyl-methacrylamide, N-(1,1-dimethyl-3-dimethylaminopropyl)-acrylamide, N-(1,1-dimethyl-3-dimethylaminobutyl)-acrylamide, N-(1-methyl-1,3-diphenyl-3-diethylaminopropyl)methacrylamide, 1-vinylimidazole, 1-vinyl-2-methylimidazole, 1-vinyl-2-ethylimidazole, 1-vinyl-2-phenylimidazole, 1-vinyl-2,3-dimethylimidazole, 1-vinyl-2,4,5-trimethylimidazole, diallyldiethylammonium chloride, (3-methacryloyloxy)propyltrimethylammonium chloride, (3-methacryloyloxy)ethyltrimethylammonium chloride, (3-methacrylamido)propyltrimethylammonium chloride, trimethyl-3-(1-acrylamido-1,1-dimethyl-propyl)ammonium chloride, trimethyl-3-(1-acrylamido-1,1-dimethylbutyl)ammonium chloride, dimethylacrylamido-propyl-4-trimethylammoniobutenyl-2-ammonium chloride, 2-acrylamidomethoxy)ethyltrimethylammonium chloride and diallyldimethylammonium chloride, and optionally one or more silanes b) selected from the group of the ethylenically unsaturated silanes and mercaptosilanes in the presence of one or more water-soluble polymers c), using the water-soluble polymers c) in stage A) to an extent of 20% to 95% by weight, based on the total weight of the amount of water-soluble polymers c) and ethylenically unsaturated monomers a) used in the polymerization, and optionally B) condensation of one or more silicon compounds of the general formula n SiR 1 4-n or of one or more condensation products of the formula, where R is an optionally substituted alkyl or aryl radical having 1 to 20 carbon atoms or a hydrogen atom, R 1 is an optionally substituted hydrocarbyl radical or a hydrogen atom, and n assumes a value from 1 to 4.