| abstract |
(57) Abstract: While stirring a hydrocarbon solution of a surfactant having an HLB of 8 to 12, an aqueous solution of a hydrophilic unsaturated monomer or a mixture thereof is introduced into the hydrocarbon solution while stirring, Reverse-phase suspension polymerization is carried out under the combined action of a radical polymerization initiator and temperature, and when the above-mentioned monomer has been polymerized, a second hydrophilic unsaturated monomer or a mixture thereof is introduced into the reaction medium in the form of an aqueous solution. Extracting the hydrocarbon phase and water by distillation and drying when the second monomer has polymerized, A method for producing a powdery hydrophilic polymer having a linear or branched chain and optionally crosslinked, which has a high rate of dissolution or swelling in water or an aqueous fluid. SOLUTION: A second monomer is introduced at a polymerization temperature, and the amount of the monomer aqueous solution is adjusted so that the volume ratio of the aqueous solution phase to the hydrocarbon phase becomes 0.6 to 1.2. |