METHOD FOR PRODUCING HYDROPHILIZED MICROPARTICLES

摘要

Provided is a method for producing hydrophilized microparticles, wherein the discoloration of vinyl polymer microparticles can be controlled even if the fluorine gas concentration in the mixed gas used for the hydrophilization process is increased. This method for producing hydrophilized microparticles, which produces hydrophilized microparticles by performing a treatment that brings the substrate particles into contact with a mixed gas containing fluorine gas, the gas of an oxygen atom-containing compound, and an inert gas to hydrophilize the surface of the substrate particles, is characterized in that: the substrate particles are vinyl polymer microparticles with a number-based mean particle size of 1000 µm or less; the volume ratio between the fluorine gas and the oxygen atom-containing compound gas in the mixed gas (oxygen atom-containing compound gas/fluorine gas) is less than 6; and the concentration of fluorine gas in the mixed gas is 0.9 volume% or more.