Patent ID: 7081507

Claim:
A water-soluble or water-swellable copolymer obtained by free-radical copolymerization of A) 50 to 99.5% by weight of acryloyldimethyltaurine and/or acryloyldimethyltaurate based on a total weight of said copolymer, said acryloyldimethyltaurine and/or acryloyldimethyltaurate having a degree of neutralization of more than 80%, B) optionaly, one or more other olefinically unsaturated, noncationic, comonomer containing at least one oxygen, nitrogen, sulfur or phosphorus atom and having a molecular weight of less than 500 g/mol, C) one or more mono- or polyolefinically unsaturated, macromonomer each having at least one oxygen, nitrogen, sulfur or phosphorus atom and having a number-average molecular weight of greater than or equal to 200 g/mol, and D) one or more olefinically unsaturated, cationic comonomer containing at least one oxygen, nitrogen, sulfur or phosphorus atom and having a molecular weight of less than 500 g/mol, the copolymerization E) taking place in the absence of at least one polymeric additive having number-average molecular weights of from 200 g/mol to 10 9 g/mol.