Patent ID: 7906595

Claim:
A hydrophilic graft polymer prepared by a process comprising the steps of: graft polymerizing monomer components, which include unsaturated monocarboxylic acids, onto a polyalkylene oxide in a reactor to yield a hydrophilic graft polymer having side chain moieties, and treating the hydrophilic graft polymer in the reactor with a peroxide or azo-based compound to maximize conversion of the monomer components into the side chain moieties, wherein more than 90 mole % of the side chain moieties originate from the unsaturated monocarboxylic acids, and, at the end of the treating step, the residual amount of the unsaturated monocarboxylic acid, relative to the total amount of the hydrophilic graft polymer, is less than 200 ppm by mass.