Patent ID: 7351755

Claim:
A method of producing an oil-in-water emulsion containing an internally crosslinked fine resin particle, wherein the fine resin particle is encapsulated in an emulsion particle having an average particle diameter of 0.02 to 0.3 μm, comprising of a step of undergoing phase transition from a water-in-oil emulsion (Y) comprising a resin (A) having a cationic group or an anionic group, an acid or a base (B) to neutralize 20 to 150 mole percent of the cationic group or the anionic group in the resin (A), an internally crosslinked fine resin particle (C) having an average particle diameter of 0.01 to 0.2 μm and being dispersed in an oil phase, and an aqueous medium (D) to an oil-in-water emulsion (Z) by adding further aqueous medium (D) to the water-in-oil emulsion (Y).