Patent ID: 7323510

Claim:
A method for manufacturing a water-in-water polymer dispersion containing a water-soluble and/or water-swellable polymer A and at least one polymeric dispersant B, comprising: a) dispersing monomers in an aqueous phase containing the water-soluble dispersant B to form a monomer dispersion, wherein said monomers consist of one or more of the monomers (i), (ii), and (iii): (i) a non-ionic monomer of formula (I) where R 1 is a hydrogen or a methyl residue, and R 2 and R 2 are, independently of each other, hydrogen, an alkyl or a hydroxyalkyl residue with 1 to 5 C atoms; (ii) a cationic monomer of formula (II) where R 1 is a hydrogen or a methyl residue, Z 1 is O, NH or NR 4 wherein R 4 is an alkyl residue with 1 to 4 C atoms, and Y is one of wherein Y 0 and Y 1 are an alkylene residue with 2 to 6 C atoms, optionally substituted with hydroxy groups, Y 2 , Y 3 , Y 4 , Y 5 , Y 6 , Y 7 , independently of each other, are each an alkyl residue with 1 to 6 C atoms; and Z − is a halogen, acetate, or SO 4 CH 3 − ; and (iii) an amphiphilic monomer of formula (III) or (IV) where Z 1 is O, NH, NR 4 wherein R 4 is an alkyl residue with 1 to 4 carbon atoms, R 1 is a hydrogen or a methyl residue, R 8 is an alkylene residue with 1 to 6 carbon atoms, R 5 and R 6 are, independently of each other, an alkyl residue with 1 to 6 carbon atoms, R 7 is an alkyl residue with 8 to 32 carbon atoms, and Z − is a halogen, pseudo-halogen, SO 4 CH 3 or acetate, or where Z 1 is O, NH, NR 4 wherein R 4 is an alkyl residue with 1 to 4 carbon atoms, R 1 is a hydrogen or a methyl residue, R 10 is a hydrogen, alkyl, aryl and/or aralkyl residue with 8 to 32 carbon atoms, R 9 is an alkylene residue with 2 to 6 carbon atoms, and n is an integer between 1 and 50; b) adding a water-soluble salt; c) subjecting the monomer dispersion formed in b) to a radical polymerization to form a dispersion of the water-soluble or water-swellable polymer A, and, after polymerization; d) adding a water-soluble acid to the dispersion of the water-soluble and/or water-swellable polymer A; wherein the polymeric dispersant B is a cationic polymer comprising at least 30% by weight of polymerized cationic monomer, and the acid is added in an amount of from 0.1 to 5% by weight and the salt is added in an amount of up to 3% by weight, where the total quantity of salt and acid is a maximum of 5% by weight; wherein % by weight is based on the total weight of the dispersion.