To provide a method for manufacturing a nonaqueous fine particle dispersion liquid capable of converting a solvent of a latex produced by emulsion polymerization easily from an aqueous system to a nonaqueous system, wherein the nonaqueous solvent may be a compound having a comparatively high solubility into water.
The latex comprises copolymer fine particles in an aqueous phase which has an ethylenic unsaturated acid monomer unit of 5-45 mass% and a monomer unit of 95-55 mass% copolymerizable with the ethylenic unsaturated acid monomer, wherein an amount of an acid radical of a surface of the fine particle measured by conductometric titration is 0.65 mmol per 1 g of the copolymer fine particle, and 4.5 times of the amount of the acid radical derived from an acid component, existing in the aqueous phase, per 1 g of the copolymer fine particle measured by the conductometric titration. The method for manufacturing the nonaqueous fine particle dispersion liquid comprises a step of producing the latex by an emulsion polymerization method, and a step of mixing the latex with the nonaqueous solvent, the insoluble content of the copolymer to which is 30 mass% when dissolved in the solvent, and then removing the aqueous phase by centrifugal separation.
NAKAMURA YOSHIYUKI
Takashi Koyama
Teiji Tanaka