PURPOSE: To obtain a sizing agent for paper capable of readily handling by dispersing a dispersion phase of dehydro-condensation product in which at least one carboxyl group remains in unreacted state or as a salt of carboxyl group into water with a specific dispersing agent.
CONSTITUTION: This sizing agent is obtained by dispersing a dispersion phase of a dehydrocondensation product in which at least one carboxyl group remains in unreacted state or as a salt of carboxyl group into water with a dispersing agent. The dispersing agent is a cationic or amphoteric copolymer consisting of (a) 1-99wt.% cationic unsaturated monomer, (b) 1-99wt.% nonionic unsaturated monomer and (c) 0-60wt.% anionic unsaturated monomer. This dispersing agent is added to the dispersing phase in an amount of 0.1-50wt.% expressed in terms of solid content so as to impart storage stability, mechanical stability and chemical stability as an aqueous dispersion to the sizing agent and eliminate raising phenomenon of sizing effect.
IKEDA ATSUSHI
TSUDA IWAO
KOTAKI TAKASHI
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