| 摘要 |
PROBLEM TO BE SOLVED: To suppress the photocatalytic activity characteristic of titanium dioxide fine grains, to improve the weatherability thereof when blended into an organic resin and to suppress their color development properties. SOLUTION: The rutile type titanium dioxide fine grains contain a cobalt element in the crystals of titanium dioxide in a range of 0.05 to 1 wt.% expressed in terms of CoO to the titanium dioxide. The rutile type titanium dioxide fine grains are produced by neutralizing the water soluble salt of cobalt in a solvent containing water-containing titanium oxide having rutile nuclei and also having a specific surface area of≥150 m<SP>2</SP>/g, fractionating the same, and next performing firing at 300 to 1,000°C. Alternatively, the rutile type titanium dioxide fine grains are produced by adding an alkali substance to an aqueous solution with a titanium salt and a cobalt salt dissolved, neutralizing and/or hydrolyzing the titanium salt and cobalt salt, fractionating the same, and next performing firing at 300 to 1,000°C. COPYRIGHT: (C)2004,JPO
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