Emulsion polymers

Emulsion polymers obtained by emulsifying a mixture consisting of

• A) 5 to 95% by weight of at least one monomer from the group consisting of acrylonitrile, methacrylonitrile and vinylcarboxylate, and
• B) 5 to 95% by weight of acrylic esters, methacrylic esters, or mixtures thereof,
• the sum of components A)+B) being 100% by weight, in the presence of an aqueous solution or dispersion of an anionically modified polyurethane based on
• a) diisocyanates of the formula ##STR10## wherein R denotes a saturated or unsaturated aliphatic hydrocarbon radical having 1 to 35 C atoms, an aryl radical having 6 to 10 C atoms, or an araliphatic radical having 7 to 10 C atoms, in which different radicals R can be present if several radicals R are present in the same molecule side by side,
• R.sup.1 represents a divalent hydrocarbon radical, optionally containing urethane, ester and/or ether groups, in which different radicals R.sup.1 can be present at the same time if several radicals R.sup.1 are present in the same molecule, and
• m represents a whole or (on average) fractional numbers from 1 to 10,
• b) sulphonate dioles of the general formula ##STR11## in which A and B represent identical or different divalent aliphatic hydrocarbon radicals having 1 to 6 carbon atoms,
• R' represents hydrogen, an aliphatic hydrocarbon radical having 1 to 4 carbon atoms or a phenyl radical,
• X.sup..crclbar. represents an alkali metal cation or a substituted or unsubstituted ammonium group,
• n and m represent identical or different numbers from 0 to 30,
• o and p each represents 0 or 1, and
• q represents an integer from 0 to 2, and
• c) appropriate auxiliaries and additives which polyurethane at least partially contains incorporated acylurea groups of the formula ##STR12## in which R denotes an organic radical, preferably a saturated or unsaturated aliphatic hydrocarbon radical having 1-35 C atoms, an aryl radical having 6-10 C atoms or an araliphatic radical having 7-10 C atoms, in which different radicals R can be present, if several radicals R are present side by side in the same molecule, and subjecting the resulting emulsion to a polymerization initiated by free radicals.