Hodogaya Chemical Co., Ltd.

National Institute of Advanced Industrial Science and Technology

Atsushi Kisuno

Tatsuo Ansai

Shihoko Aizawa

Toshimi Shimizu

Masaki Kogiso

Masumi Asakawa

The present invention provides a method for obtaining O/W emulsions by emulsifying various to-be-emulsified material without the use of any organic solvent, and drying and making into powder the O/W emulsion. The invention relates to a method for producing an O/W emulsion including after preliminarily dispersing a to-be-emulsified material and an interfacially active organic compound in water, heating the preliminary dispersion to a temperature equal to or higher than the melting point of the to-be-emulsified material and equal to or higher than the phase transition temperature of a self-assembled product of the interfacially active organic compound in the absence of an organic solvent, and performing emulsification under a pressure.

Method for preparation of aqueous emulsion using interfacially active organic compound as emulsifying agent

An organic solvent-less O/W type emulsion having an excellent stability for storage and water-dilution is produced by a specific process in which (1) a mixture of (a) water with (b) an oily substance selected from oily effective materials and oily liquid materials, the oily substance and water being capable of forming an interface therebetween, (c) a high molecular weight surfactant and (d) a low molecular weight surfactant is stirred at a temperature of 40.degree. C. or less, to provide an O/W type emulsion; (2) the emulsion is heated to gel the emulsion; (3) the gel is heated to phase invert from O/W to W/O; (4) the W/O emulsion is cooled to a temperature below the gelling temperature; and (5) the resultant O/W emulsion is further stirred, and optionally in or after the cooling step (4), a particulate solid substance or an aqueous suspension thereof is mixed with the emulsion.

Process for producing a solvent-less O/W type emulsion

A stable aqueous suspension of composite particles each including a core formed from a solid or liquid particle and a coating layer formed on the core particle and including at least one high molecular weight surfactant compound having an average molecular weight of 1100 or more and at least one low molecular weight surfactant compound having an average molecular weight of 1100 or less and at least 400 below the average molecular weight of the high molecular weight surfactant compound and optionally a suspension stabilizer, is produced by subjecting a particulate solid substance or a liquid substance to a suspending treatment in an aqueous medium containing the above-mentioned high and low molecular weight surfactant compounds, and optionally the suspension stabilizer.

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Tsukuba, Japan

Atsushi Kisuno