KATIONISCHES LEIMUNGSMITTEL FUER PAPIER UND VERFAHREN ZU SEINER HERSTELLUNG

Cationic sizing agents for paper in the form of an aqueous colloid-disperse solution having average particle diameters of from 15 to 200 nm are obtained by dissolving a water-soluble cationic, chemically uniformaly composed terpolymer compound of: (a) from 7 to 40% by weight of N,N-dimethylaminoethyl acrylate and/or methacrylate, (b) from 45 to 80% by weight of styrene, and (c) from 4 to 40% by weight of acrylonitrile in an aqueous medium, the total of components (a) to (c) always amounting to 100% by weight and at least 10% of the N,N-dimethylamino groups of the terpolymer being quaternized and the rest being protonated, and by emulsifying, in the presence of from 10 to 70% by weight, based on the following monomer mixture, of this emulsifier, (d) acrylonitrile or methacrylonitrile in quantities of from 5 to 95% by weight, with (e) C1-C12-alkyl esters of acrylic acid and/or of methacrylic acid in quantities of from 5 to 95% by weight, the total of components (d) and (e) amounting to 100% by weight, and by subjecting the emulsion thus obtained to a radically initiated emulsion polymerization process at temperatures of from 20 DEG to 150 DEG C.