Preparation of silicone microemulsions

Abstract

A mechanical method of making an oil-in-water microemulsion containing (A) a polysiloxane and (B) an inert fluid selected from an inert siloxane fluid and an inert organic fluid, where the average emulsion particle size is between 1 and 140 nanometers, is disclosed. The process involves the following steps: i) preparing an oil phase comprising a polysiloxane containing mixture by the polymerization of silane or siloxane containing monomers and/or oligomers in the presence of an inert fluid, a suitable catalyst and optionally an end-blocking agent; and ii) where required quenching the polymerization process; wherein the inert fluid is substantially retained within the resulting polysiloxane containing mixture; iii) if required, mixing one or more surfactants into the oil phase; iv) adding water to the oil phase, followed by applying agitation or shear to the mixture to arrive at an oil-in-water microemulsion; v) optionally diluting the oil-in-water microemulsion by adding more water.