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AssigneeJGC Catalysts and Chemicals Ltd.
InventorsYoichi Ishihara, Hiroyasu Nishida
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Provided are silica-based fine particle dispersion sols, processes for producing the sols, coating compositions containing the dispersion sol, curable coating films obtained from the coating composition, and substrates having the coating film. A process includes (1) mixing an aqueous aluminate solution to an alkaline silica sol which contains water-dispersible silica fine particles in a given ratio; (2) heating the mixture liquid obtained in the step (1) to 60 to 200° C. and stirring the mixture liquid at the temperature for 0.5 to 20 hours; and (3) contacting the mixture liquid obtained in the step (2) with a cation exchange resin to remove by ion exchange alkali metal ions contained in the mixture liquid and thereby controlling the pH of the mixture liquid to be in the range of 3.0 to 6.0.
A silica-based fine particle dispersion sol which comprises silica-based fine particles having a negative charge on the surface and has a pH in an acidic region from 3.0 to 6.0, wherein the silica-based fine particles are chain particles having an average particle diameter in the range of 5 to 50 nm as calculated by the equation (L +D)/2 wherein L is the longitudinal length and D is the lateral length measured with respect to a transmission electron micrograph, and the surface of the silica-based fine particles which has been modified with aluminum comprises a composite oxide of silica-alumina, and the amount of the modification by aluminum is in the range of 0.05×10−6 to 2.0×10−6 mol/m2 in terms of Al2O3 per unit surface area of the silica-based fine particles.
A silica-based fine particle dispersion sol which comprises silica-based fine particles having a negative charge on the surface and has a pH in an acidic region from 3.0 to 6.0, wherein the surface of the silica-based fine particles which has been modified with aluminum comprises a composite oxide of silica-alumina, and the amount of the modification by aluminum is in the range of 0.05×10−6 to 2.0×10−6 mol/m2 in terms of Al2O3 per unit surface area of the silica-based fine particles, wherein at least part of aluminum that has modified the surface of the silica-based fine particles is in the form of a silica/alumina composite oxide represented by Formula (I) below:
Dependencies are inferred from the claim text.