| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for easily preparing a water-soluble polycarboxylic acid copolymer by inhibiting gel formation in the polymer without adding any additives. SOLUTION: The preparation method of the water-soluble polycarboxylic acid copolymer comprises a step of dropping and polymerizing an aqueous solution containing a monomer component, provided that values A, B and C satisfy the relation: (1) A×B×C/10,000<40 (wherein A is the concentration (mass%) of an aqueous solution of a homopolymerizable monomer dropped in the polymerization step; B is the viscosity (mPa s) of an obtained aqueous solution of the water-soluble copolymer containing 45 mass% water-soluble copolymer, determined at 20°C, pH7; and C is the content (mass%) of the homopolymerizable monomer component in the water-soluble copolymer composition). COPYRIGHT: (C)2008,JPO&INPIT
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