Patent ID: 8623343

Claim:
A copolymer obtainable by polymerization of a) at least 60% by weight of one α,β-ethylenically unsaturated monomer a) of the general formula V where R 14 and R 15 , independently of one another, are selected from the group consisting of hydrogen, C 1 -C 8 linear- or branched-chain alkyl, methoxy, ethoxy, 2-hydroxyethoxy, 2-methoxyethoxy and 2-ethoxyethyl, R 17 is hydrogen or methyl, R 18 is alkylene or hydroxyalkylene having 1 to 24 carbon atoms, optionally substituted by alkyl, g is 0 or 1, Z is nitrogen when g=1 or oxygen when g=0, R 25 and R 26 are in each case and independently of one another selected from the group consisting of hydrogen, C 1 -C 40 linear- or branched-chain alkyl, formyl, C 1 -C 10 linear- or branched-chain acyl, N,N-dimethylaminoethyl, 2-hydroxyethyl, 2-methoxyethyl, 2-ethoxyethyl, hydroxypropyl, methoxypropyl, ethoxypropyl or benzyl, R 27 is H or C 1 -C 4 alkyl, An is a halogen ion, CH 3 SO 4 − , C 2 H 5 SO 4 − , or (SO 4 2− ) 0.5 , b) at least one α,β-ethylenically unsaturated monomer b) of the general formula II where R 1 to R 3 , independently of one another, are hydrogen, C 1 -C 4 -alkyl or phenyl; c) at least one α,β-ethylenically unsaturated monomer c) of the general formula III where one of the radicals R 4 to R 6 is a group of the formula CH 2 ═CR 7 — where R 7 ═H or C 1 -C 4 -alkyl and the other radicals R 4 to R 6 , independently of one another, are H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, where R 4 and R 5 , together with the amide group to which they are bonded may also be a lactam having 5 to 8 ring atoms, and where R 5 and R 6 , together with the nitrogen atom to which they are bonded, may also be a five- to seven-membered heterocycle.