Patent ID: 7601397

Claim:
A copolymer prepared by copolymerization of (a) a total of from 3.5 to 20% by weight of at least one polymerizable acid selected from the group consisting of (a1) ethylenically unsaturated C 3 -C 10 -monocarboxylic acids, (a2) ethylenically unsaturated C 4 -C 10 -dicarboxylic acid or their anhydrides, (b) from 4 to 10% by weight of at least one compound of the general formula I wherein the sum of (a) and (b) being in the range from 7.5 to 24% by weight, (c) from 60 to 92.5% by weight of at least one compound of the general formula II (d) from 0.01 to 0.5% by weight of at least one compound of the general formula III (e) from 0 to 10% by weight of (meth)acrylonitrile, (f) from 0 to 10% by weight of at least one conjugated diolefin, (g) from 0 to 10% by weight of at least one vinylaromatic compound of the general formula IV wherein the variables are defined as follows: R 1 and R 2 are identical or different and are selected from hydrogen and C 1 -C 10 -alkyl, R 3 and R 4 are identical or different and are selected from hydrogen, C 1 -C 20 -alkyl and phenyl,or or R 3 and R 4 together are C 2 -C 10 -alkylene, substituted or unsubstituted, R 5 is selected from C 1 -C 20 -alkyl and phenyl, R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are identical or different and are selected from hydrogen and C 1 -C 10 -alkyl, x is an integer in the range from 0 to 12, y is selected from 0 and 1, wherein x is chosen to be not equal to 0 when y is 1, k is an integer in the range from 0 to 3, wherein the copolymer may be completely or partly neutralized with alkali or ammonium and data in % by weight being based in each case on the total copolymer weight.