Fuji Photo Film Company, Limited

Nobuo Yamamura

Osamu Takahashi

Yasuo Mukunoki

Motoaki Takeda

Yutaka Nakagawa

Shungi Ogawa

A process for preparing an aqueous dispersion of a pigment is disclosed. The process involves providing a surface active agent having a solubility of 0.1% or less in water at a temperature of about 25.degree. C. The agent is also soluble in an organic solvent. The agent is dispersed in water to provide an aqueous dispersion of the agent. The pigment is then dispersed in the aqueous dispersion of the agent to form the aqueous dispersion of the pigment. The dispersion causes less foaming, aggregation and sedimentation of the pigment particles when the dispersion is stored. The dispersion is particularly useful when utilizing carbon black as the pigment and applying the dispersion to the field of photographic materials. The presence of the surface active agent does not have secondary effects on photographic materials.

Process for preparing aqueous dispersion of pigment

A process for emulsification which comprises producing an oily phase solution of a hydrophobic material in a dissolving-emulsifying tank equipped with a high speed dispersing means by stirring the hydrophobic material directly or dissolving the hydrophobic material or a hydrophobic material and an emulsifying agent in an organic solvent with heating, forming a water-in-oil emulsion by adding water or water and an emulsifying agent to said solution of the hydrophobic material with stirring, continuing the addition of water or water and the emulsifying agent to form an oil-in-water emulsion by phase inversion, adding a water-soluble binder to said oil-in-water emulsion and stirring the emulsion to form the desired oil-in-water emulsion.

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Minami-ashigara, Japan

Nobuo Yamamura