METHOD FOR PRODUCING CATIONIC SURFACE SIZING AGENT, AND SIZING AGENT OBTAINED BY METHOD

摘要

The present invention pertains to a method for producing a cationic surface sizing agent, the method containing: a first step for obtaining a copolymer (A) by solution-polymerizing, while in the presence of a chain-transfer agent, a monomer mixture that contains specific proportions of a monomer (a) containing a tertiary amino group, a specific (meth)acrylic acid ester (b), and a styrene (c); a second step for obtaining a copolymer (B) by polymerizing the copolymer (A) and a hydrophobic monomer (d) in a manner such that the copolymer (A) constitutes a specific proportion, while in the presence of a surfactant, and in an oxidation-reduction system that uses a water-soluble, free-radical initiator and a heavy metal sa and a third step for obtaining quaternary ammonium salt of the copolymer (B) by quaternizing a tertiary amino group present in the copolymer (B).