PURPOSE: To produce a powdery, water-soluble polymer, by adding dropwise, simultaneously and slowly a solution of a mixture of an unsaturated carboxylic acid and an unsaturated amide in an aqueous medium and a solution of a radical initiator in an aqueous medium to an aqueous medium of a specified pH value and effecting the copolymerization of the monomers.
CONSTITUTION: In copolymerizing an unsaturated carboxylic acid of formula I (wherein X is -H, -CH3, or -COOH, Y is =CH2, =CHCH2, or =CHCOOH, and Z is -COOH, -CH2COOH, -CH2CH2COOH, or a group of formula II), e.g., (methacrylic acid, with an unsaturated amide of formula III (wherein X is -H or -CH3, and Y is -H or -CH2OH), e.g., (meth)acrylamide; an aqueous medium solution of these monomers prepared by uniformly mixing solutions of the monomers and an aqueous medium solution of a radical initiator are added dropwise, simultaneously and slowly to an aqueous medium of pH≤5, kept at the polymerization temperature, and the copolymerization of the monomers is effected to produce a powder, water-soluble polymer.
TSUTSUMI YOSHITAKA
NAKAZAWA HIDEAKI
HATOYA TAKASHI
