Patent ID: 8629230

Claim:
A method for manufacturing a carboxyl group-containing water-soluble polymer by carrying out in an inert solvent a reaction of a monomer component containing an α,β-unsaturated carboxylic acid and a polymerizable compound having two or more ethylenically unsaturated groups of at least one kind selected from the group consisting of pentaerythritol allyl ether, polyallyl saccharose, diethylene glycol diallyl ether and polyethylene glycol diallyl ether, comprising: step (A) of preparing a reaction vessel in which an inert solvent is charged, and step (B) of continuously adding a monomer solution wherein the monomer component is dissolved in an inert solvent at a concentration of 20 to 50% by volume to the inert solvent charged in the reaction vessel, wherein, the amount of the inert solvent charged in the reaction vessel in step (A) is set so that the concentration of the monomer component in the total amount summed up with the monomer solution is 10 to 24% by volume, and the time period until completion of continuous addition of the total amount of the monomer solution in step (B) is set so that the conversion of the monomer component is 60% or more at the time of completion of addition of the total amount of the monomer solution.