Cationic surface sizing agent and paper coated with the sizing agent

Abstract

To heighten the effect of sizing even on paper containing no sizing agent as an internal additive and to enable solution polymerization in a small amount of an organic solvent and thereby heighten productivity. A cationic surface sizing agent which comprises a copolymer obtained by polymerizing (a) 15-35 wt.% monomer containing a tertiary amino group, (b) 30-85 wt.% C1-4-alkyl (meth)acrylate, and (c) 1-50 wt.% styrene compound by solution polymerization in an organic solvent in the presence of a chain-transfer agent. The copolymer may have undergone a cationic-nature-imparting treatment with a quaternizing agent. The constituent monomers for the copolymer may further include (d) 0-20 wt.% other copolymerizable vinyl monomer. This cationic surface sizing agent is applied to paper.

Description

technical field [0001] The present invention relates to a cationic surface sizing agent, and more specifically, to a cationic surface sizing agent, even for paper that does not contain an internal sizing agent or has an extremely low Stockigt sizing degree A cationic surface sizing agent that is also excellent in sizing effect and can reduce the amount of solvent during polymerization, thereby eliminating or simplifying the solvent distillation process, and paper coated with the sizing agent. Background technique [0002] As conventional cationic surface sizing agents, known are cationic copolymers in which styrene and tertiary amino-containing monomers are copolymerized and quaternized, or hydrophobic monomers are emulsion-polymerized in the presence of the cationic copolymers. made product. Its specific example is as follows. [0003] (1) Patent Document 1 [0004] In order to improve the sizing effect, a surface sizing agent as follows is disclosed: in an organic solve...

AI Technical Summary

Problems solved by technology

In the presence of cationic copolymers such as Patent Documents 4 to 6, the production process of the surface sizing agent by the two-stage polymerization method of emulsion polymerization of hydrophobic monomers becomes complicated

Patent Document 7 is an internal sizing agent (see the upper right column on page 2), and Patent Document 9 uses acrylonitrile as an essential component, so sufficient sizing properties or ease of handling cannot be guaranteed