Patent ID: 7101836

Claim:
Graft polymers comprising: (A) a polymeric polyether grafting base devoid of monoethylenically unsaturated units, and (B) polymeric side chains formed from copolymers of two different monoethylenically unsaturated monomers (B1) and (B2) which each comprises at least one nitrogeneous heterocycle, wherein said side chains (B) account for 60 to 95% by weight of the total polymer; wherein (B1) is a cyclic N-vinylamide of the formula I where R is C 1 –C 5 -alkyl, and R 1 is hydrogen or C 1 –C 4 -alkyl; and wherein said monomer (B2) contains a nitrogenous heterocycle selected from the group consisting of the pyrroles, pyrrolidines, pyridines, quinolines, isoquinolines, purines, pyrazoles, imidazoles, triazoles, tetrazoles, indolizines, pyridazines, pyrimidines, pyrazines, indoles, isoindoles, oxazoles, oxazolidones, oxazolidines, morpholines, piperazines, piperidines, isoxazoles, thiazoles, isothiazoles, indoxyls, isatins, dioxindoles and hydantoins and derivatives thereof, and barbituric acid and uracil and derivatives thereof.