Metal oxide particles having improved hydrophobicity, highly concentrated metal oxide sol, and methods for producing same

Abstract

[Problem] To provide: metal oxide particles that can be highly concentrated in an organic solvent, which is a dispersion medium for a metal oxide sol, and can also be redispersed in the organic solvent; a metal oxide sol containing the metal oxide particles; and a method for producing same. [Solution] Metal oxide particles surface-coated with a hydrolysate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2), wherein the metal oxide particles contain a basic compound (I) (excluding ammonia), have a hydrophobicity of 30-80 vol% as measured by a methanol titration method, and can be dispersed at a particle refractive index of 1.4-3.0 and at a metal oxide concentration of at least 40 mass% in an organic solvent, or can be dispersed at a particle refractive index of at least 1.1 and less than 1.4 and at a metal oxide concentration of at least 25 mass% in an organic solvent.