Water-soluble polymer dispersion, paper force enhancing agent, filter water improving agent for papermaking, and yield enhancing agent for papermaking

摘要

PROBLEM TO BE SOLVED: To provide a water-soluble polymer dispersion in which a particle diameter is small and uniform, and which excels in storage stability, and a paper strength additive which excels in storage stability, does not disarrange a balance of an obtained paper, and can impart a high paper strength effect to paper, and to provide a filtration improvement agent for papermaking, and a retention aid for papermaking.;SOLUTION: The water-soluble polymer dispersion is obtained by dispersing a water-soluble polymer (A) obtained by copolymerizing at least a cationic radically polymerizable monomer (a1) and a radical polymerization component (a) containing (meth)acrylamide (a4) in an aqueous salt solution in which a salt concentration is at least 10 wt.% and at most a saturating concentration, by using the following (B) and (C) components. (B) component: a polymeric dispersant obtained by copolymerizing a radical polymerization component (b) including a cationic radically polymerizable monomer (b1), (meth)acrylamide (b5), and a crosslinkable monomer (b3) and/or N-substitution (meth)acrylamide (b4) shown by general formula (1) CH2=C(R1)-CONR2(R2), wherein R1 denotes a hydrogen atom or a methyl group, and R2 each independently denote a 1-4C straight chain or branched chain alkyl group, (C): a polyhydric alcohol of a carbon number of 2-10.;COPYRIGHT: (C)2013,JPO&INPIT