Patent ID: 8158699

Claim:
A water-soluble sulfo group-containing copolymer consisting of a) 40 to 93.89 mol % of structural groups of the formula (I) wherein: R 1 is hydrogen or methyl: R 2 , R 3 , R 4 are hydrogen, an aliphatic hydrocarbon radical having 1 to 6 C atoms or a phenyl radical optionally substituted by methyl groups; and M is hydrogen, a mono- or divalent metal cation, ammonium or an organic amine radical; and a is ½ or 1; b) 6 to 59.89 mol % of structural groups of the formula (II) wherein Y is O, NH or NR 5 , V is —(CH 2 ) x —, R 5 and R 6 are independently an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms or an aryl radical having 6 to 14 C atoms, where the radicals can optionally be substituted by hydroxyl, carboxyl or sulfonic acid groups, R 7 is R 5 or R 6 , —(CH 2 ) x —SO 3 M a , x is from 1 to 6, X is F, Cl, Br, I, C 1 - to C 4 -alkylsulfate or C 1 - to C 4 -alkylsulfonate and R 1 , M and a are as defined above; and at least one of c) and d), wherein c) is from 0.1 to 10 mol % of structural groups of the formula (III) wherein Z is —(CH 2 ) q —O(C n H 2n O) p —R 8 , or —COO(C n H 2n O) p —R 8 n is from 2 to 4; p is from 1 to 200; q is from 0 to 20; R 8 is H or a C 1 - to C 4 -alkyl radical; and R 1 is as defined above; and d) is from 0.01 to 0.5 mol % of structural groups of the formula (IV) wherein U is —COO(C n H 2n O) p —R 9 , or —(CH 2 ) q —O(C n H 2n O) p —R 9 R 9 is and an unsaturated or saturated, linear or branched aliphatic alkyl radical having 10 to 30 C atoms, R 10 is H, a C 1 - to C 6 -alkyl or arylalkyl group having a C 1 - to C 12 -alkyl and C 6 - to C 14 -aryl radical; y is 1 to 3; and R 1 , n, p and q are as defined above.