Patent ID: 8609757

Claim:
A method for manufacturing a water-in-water polymer dispersion, the method comprising: free radical polymerizing an aqueous reaction mixture comprising (i) a cationic polymeric dispersant, and (ii) a monomer composition comprising (ii-a) at least 5 wt.-% of a non-ionic monomer of formula (I) wherein R 1 means hydrogen or C 1 -C 3 -alkyl, and R 2 and R 3 mean, independently of each other, hydrogen, C 1 -C 5 -alkyl or C 1 -C 5 -hydroxyalkyl, based on a total weight of monomers; (ii-b) at least 5 wt.-% of a cationic monomer according to general formula (II) wherein R 4 means hydrogen or C 1 -C 3 -alkyl, Z 1 means O or NR 5 with R 5 being hydrogen or C 1 -C 3 -alkyl, Y 0 means C 2 -C 6 -alkylene, optionally substituted with one or more hydroxy groups, Y 1 , Y 2 , Y 3 , independently of each other, mean C 1 -C 6 -alkyl, and X − means halogen, pseudo-halogen, acetate, or SO 4 CH 3 − , based on the total weight of monomers; (ii-c) 0.0001 to 1.25 wt.-% of one or more cross-linkers, based on the total weight of monomers; (ii-d) 0 to 1.25 wt.-% of one or more hydrophobic (meth)acrylic acid C 4-18 -alkyl esters, based on the total weight of monomers; and (ii-e) optionally, a further ethylenically unsaturated monomer, before, after, or before and after the free radical polymerizing, adding a water-soluble salt in a quantity of 0.1 to 5.0 wt.-%, based on a total weight of the aqueous reaction mixture, to the aqueous reaction mixture, to obtain a water-in-water polymer dispersion such that the water-in-water polymer dispersion comprises a cross-linked cationic copolymer.