RUTILE-TYPE TITANIUM OXIDE ORGANOSOL, METHOD FOR PRODUCING RUTILE-TYPE TITANIUM OXIDE ORGANOSOL, HIGH REFRACTIVE INDEX COATING-FORMING COMPOSITION USING SAID RUTILE-TYPE TITANIUM OXIDE ORGANOSOL, AND OPTICAL ELEMENT

摘要

[Problem] There has been demand for a titanium oxide organosol that has a high transparency and a high refractive index and that also exhibits an excellent viscosity stability over time. [Solution] A rutile-type titanium oxide organosol according to the present invention comprises a silane coupling agent, a basic additive acting as a deflocculant, a water-insoluble solvent, and rutile-type titanium oxide particles that have been surface-treated with a hydrous oxide of at least one metal species selected from Zr, Ce, Sn, and Fe, the rutile-type titanium oxide organosol being characterized in that the Ti ratio contained in the colloidal particles in the rutile-type titanium oxide organosol is at least 60 mass% when calculated as the oxide, and the ratio of metal species at the colloidal particle surface derived from x-ray photoelectron spectroscopy is 20-50 mass%.