Taisei Chemical Industries, Ltd.

Masahiro Sekine

Takashi Sunamori

Mitsuo Tamazawa

Disclosed is a method for producing an aqueous nail enamel composition comprising the following procedure: an aqueous mixture which comprises, as essential components, water and a pigment of 3 &mgr;m or less in average particle size at a concentration of the pigment of 60% or less and is previously subjected to contact treatment with a substance having an ion exchangeability is kneaded under heating with a polyester polymer having a chemical structure containing a phenyl group and having a weight-average molecular weight of 2000-20000 and a softening point of 120&deg; C. or lower in the state of the polymer being molten and simultaneously the volatile matter contained is removed under reduced pressure; the resulting mixture (A) comprising the polyester polymer and the pigment dispersed in the polyester polymer, said pigment finally having the inherent average particle size, is dissolved in an organic solvent at a concentration of the mixture (A) of 50% by weight or less; then the solution is mixed with an organic solvent solution (B) containing 80% or less of a resin containing 1-5 meq/g of a functional group capable of being dissociated to a cation or an anion; then the resulting mixture is neutralized and allowed to contact with a substance having ion exchangeability before and/or after carrying out phase inversion by dilution with addition of water to remove ionic impurities; the organic solvent is distilled off; and the residue is again allowed to contact with a substance having ion exchangeability to obtain an aqueous nail enamel composition comprising a color polymer composition dissolved in water alone as an essential component and containing less ionic impurities and substantially no organic solvent and film-forming aid. Thus, there is provided an aqueous nail enamel compositions which contains no organic solvent, is excellent in safety for human body and long-term storage stability, and has beautiful color and gloss, and high-coating film strength and adhesion.

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Yachiyo, Japan

Masahiro Sekine