Titanium oxide, conductive titanium oxide, and processes for producing these

Patent metadata

Field	Value
Publication number	US-9809461-B2
Application number	US-201615219653-A
Country	US
Kind code	B2
Filing date	Jul 26, 2016
Priority date	Mar 7, 2006
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Titanium dioxide and an electro-conductive titanium oxide which each includes particles having a large major-axis length in a large proportion and comprises columnar particles having a satisfactory particle size distribution. A titanium compound, an alkali metal compound, and an oxyphosphorus compound are heated/fired in the presence of titanium dioxide nucleus crystals having an aspect ratio of 2 or higher to grow the titanium dioxide nucleus crystals. Subsequently, a titanium compound, an alkali metal compound, and an oxyphosphorus compound are further added and heated/fired in the presence of the grown titanium dioxide nucleus crystals. Thus, titanium dioxide is produced which comprises columnar particles having a weight-average major-axis length of 7.0-15.0 μm and in which particles having a major-axis length of 10 μm or longer account for 15 wt. % or more of all the particles. A solution of a tin compound and a solution of compounds of antimony, phosphorus, etc. are added to a suspension obtained by suspending the titanium dioxide. The particles are sedimented. Subsequently, the product obtained is heated/fired to produce an electro-conductive titanium oxide which comprises the titanium dioxide and an electro-conductive coating formed on the surface thereof.

First claim

The invention claimed is:

1. Titanium dioxide in the shape of columnar particles, wherein:
the particles have a weight-average major-axis length of 8.0-14.0 μm and the particles having a major-axis length of 10 μm or larger are included in a proportion of 35% by weight or more, and the particles have a specific surface area of 1.0-3.5 m 2 /g;
the particles having a major-axis length of less than 5.0 μm are included in a proportion of 20% by weight or less;
the particles having a major-axis length of 10-20 μm are included in a proportion of 25% by weight or more;
the particles have a weight-average minor-axis length of 0.3-0.8 μm; and
the aspect ratio (weight-average major-axis length/weight-average minor-axis length) is in the range of 5-40.

2. A process for producing titanium dioxide comprising the steps of:
mixing titanium dioxide nucleus crystals, a titanium compound, an alkali metal compound and an oxyphosphorus compound prior to heating and firing, wherein:
the titanium dioxide nucleus crystals have an aspect ratio of 5-40 and a weight-average major-axis length of 4.0-6.0 μm;
the amount of titanium dioxide nucleus crystals used is in the range of 3-60 parts by weight of the total TiO 2 content, and the amount of titanium compound used is in the range of 40-97 parts by weight of the total TiO 2 content, and thus the total amount of titanium dioxide nucleus crystals and titanium compound is 100 parts by weight of the total TiO 2 content;
the amount of alkali metal compound used is 0.1-4 parts by weight based on 1 part by weight of the total TiO 2 content in the mixture in terms of the alkali metal element; and
the amount of the oxyphosphorus compound used is 0.01-0.6 parts by weight based on 1 part by weight of the total TiO 2 content in the mixture in terms of phosphorus;

and
heating and firing the titanium dioxide nucleus crystals, the titanium compound, the alkali metal compound and the oxyphosphorus compound at 700-1000° C., thereby producing titanium dioxide in the shape of columnar particles, wherein:
the ratio of weight-average major-axis length of the titanium dioxide nucleus crystals after growing to that of the titanium dioxide nucleus crystals used reaches 2-7,
the particles have a weight-average major-axis length of 8.0-14.0 μm and the particles having a major-axis length of 10 μm or larger are included in a proportion of 35% by weight or more, and the particles have a specific surface area of 1.0-3.5 m 2 /g;
the particles having a major-axis length of less than 5.0 μm are included in a proportion of 20% by weight or less;
the particles having a major-axis length of 10-20 μm are included in a proportion of 25% by weight or more;
the particles have a weight-average minor-axis length of 0.3-0.8 μm; and
the aspect ratio (weight-average major-axis length/weight-average minor-axis length) is in the range of 5-40.

Assignees

• Ishihara Sangyo Kaisha

Inventors

• Isobe Kaoru
• Chiba Katsuichi
• Sakamoto Takanori

Classifications

• C04B2235/5296

  with a defined aspect ratio, e.g. indicating sphericity · CPC title

• C04B2235/3886

  Refractory metal nitrides, e.g. vanadium nitride, tungsten nitride · CPC title

• C04B35/62805

  Oxide ceramics · CPC title

• C04B35/62886

  by wet chemical techniques · CPC title

• C01G23/047 Primary

  Titanium dioxide · CPC title