Patent ID: 8586639

Claim:
An emulsion of the oil-in-water (O/W) type, containing: a) an oil disperse phase comprising a substantially water-insoluble component or optionally a plurality of substantially water-insoluble components, b) an aqueous phase, c) pyrogenic silica at an oil-water interface between the oil phase and the aqueous phase, the pyrogenic silica being partly silylated such that the content of non-silylated surface silanol groups on the silica surface is from not more than 95% to not less than 50% of the starting silica, or from 1.7 to 0.9 SiOH groups per nm 2 of silica surface, the dispersion fraction of the surface energy gamma-s-D being from 30 to 80 mJ/m 2 and the specific BET surface area being from 30 to 500 m 2 /g, d) an electrolyte content in the aqueous phase, which is set such that the ionic strength I of the solution is greater than 10 −6 mol/l, where the ionic strength is defined as I=½·Σc i ·z i 2 where c i in this case is the concentration of the ion i in the solution, z i is the charge of the ion i, wherein the mean particle size of the disperse phase, measured by means of laser diffraction, is from 0.5 μm to 500 μm, wherein the emulsion is prepared by in a first step, a dispersion (1) of the partly silylated pyrogenic silica c) in a portion of the aqueous phase is prepared: in a second step, a viscous preemulsion (2) is prepared by mixing the dispersion (1) with all the oil of the oil phase a), wherein the viscous preemulsion contains the total amount of partly-silylated pyrogenic silica contained in the oil-in-water emulsion: and in a third step, mixing in a remaining portion of the aqueous phase, wherein an electrolyte is added during at least one of steps (1) to (3) such that the oil-in-water emulsion has a viscosity greater than 1 mPa·s at a conductivity of the water-in-oil emulsion which is greater than or equal to 1 μS/cm, and wherein the electrolyte adjusts the viscosity of the oil-in-water emulsion to a viscosity higher than when the electrolyte is not present.