Patent ID: 8629224

Claim:
A polymer comprising a) at least one structural repeat unit of the formula (1) wherein R 1 is hydrogen, methyl or ethyl and A is C 1 -C 8 -alkylene, and Q + is H + , NH 4 + , Li + , Na + , K + , ½ Ca ++ , ½ Mg ++ , ½ Zn ++ or ⅓ Al +++ , and the degree of neutralization of the structural units of the formula (1) is from 50 to 100 mol %, and b) at least one structural repeat unit of the formula (2) wherein R 1 and A have the definition of R 1 and A from formula (1) and X + is selected from the group consisting of laurylamidopropyldimethylammonium, stearylamidopropyldimethylammonium, behenylamidopropyldimethylammonium, C 12-18 -alkyldimethylammonium, and C 20 -C 22 -alkyldimethylammonium ion, with the proviso that the molar ratio of the structural units of the formula (1) in which Q + is NH 4 + , Li + , Na + , K + , Ca ++ , Mg ++ , Zn ++ or Al +++ to the structural units of the formula (2) is from 97:3 to 55:45, and a corresponding alkylammonium chloride having a critical micelle concentration (CMC) <15 g/l, and d) 0% to 8% by weight based on the total weight of the polymer of crosslinking structural units originating from monomers having at least two olefinic double bonds.