METHOD FOR PRODUCING ZIRCONIA-COATED TITANIUM OXIDE MICROPARTICLES, ZIRCONIA-COATED TITANIUM OXIDE MICROPARTICLES AND USE THEREOF

摘要

[Problem] To provide titanium oxide-based microparticles, etc., said microparticles maintaining a high refractive index and yet having a suppressed photocatalytic activity. [Solution] A method for producing a dispersion of zirconia-coated titanium oxide microparticles, said method comprising: (1) a step for preparing a dispersion (1) of titanium oxide microparticles; (2) a step for adding, to the dispersion (1), 1-50 parts by mass, in terms of the mass of ZrO2 per 100 parts by mass of the titanium oxide microparticles, of an aqueous peroxidic zirconic acid solution and then aging reacted microparticles (2a), which have been obtained by the reaction between the titanium oxide microparticles and the peroxidic zirconic acid, to thereby give a dispersion (2) of a zirconia-coated titanium oxide microparticle precursor (2b); and (3) a step for adjusting the solid component concentration of the dispersion (2) to 0.01-10 mass% followed by a hydrothermal treatment.