Abstract: There is provided a colloidal particle of an oxide of at least one metal selected from the group consisting of Ti, Fe, Zr, Sn, Ta, Nb, Y, Mo, W, Pb, In, Bi, and Sr, which is capable of being dispersed in a hydrophobic organic solvent, and a hydrophilic organic solvent dispersed sol thereof or a sol thereof dispersed in a hydrophobic organic solvent having a solubility of water of 0.05 to 12% by mass, and further, a fine powder of a metal oxide colloidal particle capable of being redispersed in various organic solvents. A silane treated modified metal oxide colloidal particle on the surface of which an amine compound and 1 to 4 silyl group(s) per 1 nm2 of the surface area are bonded, and which is produced by coating a metal oxide colloidal particle as a core with a complex oxide colloidal particle.

Abstract: There is provided a method for efficiently producing an anatase-type titanium oxide sol in an extremely advantageous dispersion state. The method comprises mixing a titanium alkoxide, an organic acid, and a quaternary ammonium hydroxide with water in a molar ratio of the organic acid of 0.4 to 4.0 relative to 1 mol of a titanium atom of the titanium alkoxide and in a molar ratio of the quaternary ammonium hydroxide of 0.8 to 1.9 relative to 1 mol of the organic acid to prepare an aqueous mixed solution having a concentration in terms of TiO2 of 0.5 to 10% by mass; heating the aqueous mixed solution to 50 to 100° C. to remove an alcohol; and subjecting the resulting titanium-containing aqueous solution to a hydrothermal treatment at 110 to 170° C.

Abstract: There is provided a colloidal particle of an oxide of at least one metal selected from the group consisting of Ti, Fe, Zr, Sn, Ta, Nb, Y, Mo, W, Pb, In, Bi, and Sr, which is capable of being dispersed in a hydrophobic organic solvent, and a hydrophilic organic solvent dispersed sol thereof or a sol thereof dispersed in a hydrophobic organic solvent having a solubility of water of 0.05 to 12% by mass, and further, a fine powder of a metal oxide colloidal particle capable of being redispersed in various organic solvents. A silane treated modified metal oxide colloidal particle on the surface of which an amine compound and 1 to 4 silyl group(s) per 1 nm2 of the surface area are bonded, and which is produced by coating a metal oxide colloidal particle as a core with a complex oxide colloidal particle.

Abstract: There is provided a production method of an yttrium oxide-stabilized zirconium oxide aqueous sol and organic solvent sol capable of producing a sol having extremely advantageous transparency with which the heating condition is eased compared to that of a conventional method and secondary aggregation of the obtained colloidal particle is hardly caused. A production method of an yttrium oxide-stabilized zirconium oxide aqueous sol, characterized by comprising: a process of subjecting a mixed aqueous solution produced by dissolving an yttrium carboxylate and zirconium oxyacetate in water in an Y/(Y+Zr) atomic ratio in a range of 0.10 to 0.60 to hydrothermal treatment at 160 to 280° C. for 2 hours or more.

Abstract: There is provided a method for efficiently producing an anatase-type titanium oxide sol in an extremely advantageous dispersion state. The method comprises mixing a titanium alkoxide, an organic acid, and a quaternary ammonium hydroxide with water in a molar ratio of the organic acid of 0.4 to 4.0 relative to 1 mol of a titanium atom of the titanium alkoxide and in a molar ratio of the quaternary ammonium hydroxide of 0.8 to 1.9 relative to 1 mol of the organic acid to prepare an aqueous mixed solution having a concentration in terms of TiO2 of 0.5 to 10% by mass; heating the aqueous mixed solution to 50 to 100° C. to remove an alcohol; and subjecting the resulting titanium-containing aqueous solution to a hydrothermal treatment at 110 to 170° C.

Abstract: A production method of a zirconia sol includes; (A) mixing a dicarboxylic acid compound with a zirconium compound in an aqueous medium, in which a molar ratio of the dicarboxylic acid compound is more than 1 and less than or equal to 10 per mol of zirconium atom in the zirconium compound, and (B) adding 0.7-2.5 mol of a water-soluble organic base per mol of the dicarboxylic acid compound contained in a mixture obtained by the process (A) to the mixture and then treating hydrothermally the resultant mixture.