| 摘要 |
Finely divided, cationic, aqueous polymer dispersions which are obtainable by emulsion polymerization of ethylenically unsaturated monomers in an aqueous solution of a cationic prepolymer as a dispersant, wherein first the cationic prepolymer is prepared in the presence of polymerization initiators by polymerization of (a) from 15 to 40% by weight of a mixture of at least two different (meth)acrylates which in each case have an amino group and/or quaternary ammonium group and/or (meth)acrylamides which in each case carry an amino group and/or quaternary ammonium group, (b) from 40 to 85% by weight of at least one optionally substituted styrene, (c) from 0.5 to 5% by weight of at least one ethylenically unsaturated monomer comprising acid groups and (d) from 0 to 20% by weight of at least one nonionic, ethylenically unsaturated monomer differing from (b), the sum of (a)+(b)+(c)+(d) being 100% by weight, in a solution polymerization in a partly to completely water-miscible solvent, and water is then added to the solution/dispersion of the prepolymer, and thereafter, in the aqueous solution of the prepolymer, an emulsion polymerization is carried out, in the presence of polymerization initiators, of a monomer mixture comprising (i) from 0 to 29% by weight of at least one optionally substituted styrene, (ii) from 50 to 100% by weight of at least one C1- to C18-(meth)acrylate, (iii) from 0 to 30% by weight of at least one vinyl ester of linear or branched C1-C30-carboxylic acids and (iv) from 0 to 30% by weight of at least one nonionic ethylenically unsaturated monomer differing from (i), (ii) and (iii), the sum of (i)+(ii)+(iii)+(iv) being 100% by weight, and the solution polymerization and/or emulsion polymerization is carried out in the presence of from 0 to 10% by weight of at least one polymerization regulator.
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