| abstract |
A copolymer which comprises, in copolymerized form, (A) 60 to 99% by weight of at least one monoethylenically unsaturated polyalkylene oxide monomer of the formula I (I) in which the variables have the following meanings: X is -CH 2 - or -CO-, if Y is -O-; is -CO-, if Y is -NH-; Y is -O- or −NH-; R 1 is hydrogen or methyl; R 2 are identical or different C 2 n - C 6 -alkylene radicals, which may be arranged blockwise or randomly; R 3 is hydrogen or C 1 -C 4 -alkyl; n is an integer from 25 to 75, (B) 1 to 40% by weight of at least one quaternized nitrogen-containing monoethylenically unsaturated monomer selected from the group consisting of monomers of formula IIa to IId (IIa - IId) in which the variables have the following meanings: R is C 1 -C 4 -alkyl or benzyl; R' is hydrogen or methyl; Y is -O- or -NH-; A is C 1 -C 6 -alkylene; X– is halide, C 1 -C 4 -alkyl sulfate, C 1 -C 4 -alkylsulfonate and C 1 -C 4 -alkyl carbonate, (C) 0 to 10% by weight of anionic monoethylenically unsaturated monomers, and (D) 0 to 30% by weight of other nonionic monoethylenically unsaturatedmonomers and has an average molecular weight M w of > 100,000. |