Powder dispersion composition and dispersing method thereof

A method for producing a powder dispersion composition, the method comprising:

• mixing a powder and a dispersant in a dispersion medium with stirring in a first step and homogenizing the mixture prepared in the first step based on the principle of cavitation in a second step,
• wherein the mixture prepared in the first step, to which a flow rate is given, is passed through a throttle channel to form fine bubbles, and wherein the flow rate is given using an ultrahigh pressure flow of from 50 to 200 MPa,
• wherein the dispersion medium is selected from the group consisting of silicone oil, hydrocarbon oil, and ester oil, and the amount of the dispersion medium is from 30 to 70% by mass;
• and wherein
• the powder contains (i) surface-coated titanium dioxide particles whose particle surfaces are coated with stearic acid and aluminum oxide, and/or (ii) surface-coated zinc oxide particles whose particle surfaces are coated with hydrous silica and dimethicone, and the amount of the powder is from 0.1 to 60% by mass, wherein the dispersant has the following formula:
• wherein R1 represents a linear or branched alkyl group having from 1 to 12 carbon atoms or a phenyl group, R2 is an alkylene group having from 2 to 11 carbon atoms, m is from 10 to 120 and n is from 1 to 11, and
• wherein the dispersed powder has an average particle size of 10 times or less than that of the powder used for preparation of the powder dispersion, and wherein a polydispersity index of the average particle size of the powder dispersion composition is 0.4 or less as measured by dynamic light scattering.