Patent ID: 6849703

Claim:
A process for preparing a water-soluble polymer comprising: (A) azeotropic esterification of acrylic acid and at least one alkylpolyalkylene glycol(s), wherein said acrylic acid and said at least one alkylpolyallcylene glycol are present in a molar ratio ranging from 2 to 3:1; and wherein said azeotropic esterification takes place in the presence of at least 85% by weight (based on the weight of the alkylpolyalkylene glycol) of an organic solvent which forms an azeotrope with water; thus obtaining an esterification mixture; and (B) free-radical polymerization in an aqueous medium of the mixture obtained during esterification, wherein the organic solvent is distilled off azeotropic ally from the polymerization reaction mixture, and the water that is removed by distillation is returned to the mixture or replaced by a feed of fresh water.