Fine particle substance-containing microgel dispersions

Claim 1

A composition which is a first dispersion of first, water-insoluble, microgel particles, as the dispersed phase, dispersed in a substantially water-in-soluble organic solvent, as the continuous phase; said first, water-insoluble, microgel particles having an average particle diameter of 1000 Å or less and consisting essentially of a gel of second fine particles of a solid substance distributed in a cross-linked first polymer, said substance being different from said cross-linked first polymer, said second fine particles of said solid substance being smaller than said first, water-insoluble, microgel particles; said composition having been prepared by mixing (1) a second dispersion of said second fine particles of said solid substance, as the dispersed phase, dispersed in a first solution of an oil-soluble surface active agent in said substantially water-insoluble organic solvent, as the continuous phase, wherein said surface active agent is adsorbed or adhered on said second fine particles of said solid substance, with (2) a monomer-solubilized system prepared by adding an aqueous solution of a water-soluble monomer capable of forming said first polymer and a cross-linking agent capable of cross-linking said first polymer to a second solution of said oil-soluble surface active agent in said substantially water-insoluble organic solvent, and forming the mixture of (1) and (2) into a W/O microemulsion; then polymerizing and cross-linking said monomer to form said cross-linked first polymer in situ in said W/O microemulsion and thereby form said first microgel particles wherein said oil-soluble surface active agent is adhered to or adsorbed on said first, water-insoluble, microgel particles and is effective to disperse them in said substantially water-insoluble organic solvent.