JPS6217021A - Production of reduced titanium oxide - Google Patents

Abstract

PURPOSE:To obtain reduced titanium oxide which has high electrical conductivity and is preferable as a raw material of electrically-conductive paint at comparatively low temp. in the calcination of short time by adding boron (compd.) to titanium oxide (precursor) and calcining the mixture in an inert gas or the reducing atmosphere. CONSTITUTION:One or more kinds of boron (e.g. crystalline boron, amorphous boron) or boron compd. (e.g. bonic acid, borax) are added to titanium oxide or a substance (e.g. titanium hydroxide) made to titanium oxide by roasting. The aimed reduced titanium oxide is obtained by calcining the mixture at 500-1,100 deg.C in an inert gas atmosphere (e.g. N2, Ar atmosphere) or the reducing atmosphere (e.g. gaseous H2 atmosphere, carbonpacked atmosphere). The obtained reduced titanium oxide is a fine powdery electrically-conductive material and electrically-conductive paint can be obtained by kneading it with a binder and an electrically-conductive sheet can be obtained by kneading it with resin.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing -based titanium oxide.

(Background of the invention) In recent years, 9. With the exhibition, the need for conductive materials is increasing, and new materials that can be used as static electricity removal materials, antistatic 1F materials, and conductive materials are being developed or researched. Conventionally, these conductive materials include conductive metals such as gold, silver, platinum, copper, and nickel, carbon materials such as carbon black, metal oxides such as tin oxide and antimony oxide, and even polypyrrole and polyacetylene. Organic conductive compounds, such as ing. As a more common example, it is also used as a pigment to color cosmetics.

(Prior art) Generally, titanium oxide or a substance that becomes titanium oxide when fired (
Methods of imparting conductivity to titanium oxide (hereinafter referred to as titanium oxide) include coating the surface of titanium oxide with a conductive substance;
A method of reducing titanium oxide to obtain titanium oxide consisting of a lower oxide is known.

The former coating method involves depositing a conductive substance on the surface of titanium oxide using a physical or chemical method to obtain a titanate coated with the conductive substance. Silver, copper, nickel, tin, antimony, etc. are used. This method has the advantage of being easy to operate because it can use electroless plating technology, and it also has the advantage of imparting conductivity to the titanium oxide substrate without changing its properties, but it is expensive. There is a problem. That is, the raw material titanium oxide is generally in the form of a fine powder, and its specific surface area is 1 to 10.
0 m'/g, so in order to uniformly coat the surface of the powder and exhibit conductivity, 1 g of titanium oxide as a raw material is required.
However, 1 to 5 g of conductive material for coating is required.

This means that the coating material is the same or larger than titanium oxide in terms of needle composition, which inevitably makes the product more expensive, and also impairs the original properties of titanium oxide. Industrial applicability is also reduced.

In the latter reduction method, by firing titanium oxide in a reducing atmosphere or using a reducing atmosphere during production of titanium oxide, it exhibits conductivity expressed by the formula, TE01-x (where o<x<2). Titanium oxide consisting of a lower oxide is obtained. According to this reduction method, it is possible to obtain titanium oxide consisting of any low-dimensional oxide with different conductivity depending on the control of the reduction conditions, so it is extremely useful as a means for producing conductive titanium oxide. However, depending on the type of titanium oxide, it is difficult to reduce it, and the reduction process must be carried out at high temperatures or for a long time. Therefore, during the reduction process, the titanium oxide may melt and form a sintered body. In some cases, a phenomenon in which the crystalline state of the product changed was observed.

(Problems to be Solved by the Invention) An object of the present invention is to reduce titanium oxide to produce conductive titanium oxide in a temperature range that does not melt the object to be treated or change its crystalline state. The object of the present invention is to provide a manufacturing method capable of obtaining a target product to be reduced within a short period of time.

Another object of the present invention is to provide a manufacturing method for obtaining reduced titanium oxide, in which the physical properties of conductive titanium oxide produced by reduction firing do not lose any of the physical properties of original titanium octoxide other than conductivity. It's about doing.

A further object of the present invention is to provide a manufacturing method for obtaining reduced titanium oxide with uniform conductivity.

(Means for Solving the Problems) In order to solve the above problems, the method for producing reduced titanium oxide of the present invention includes adding boron or one type of boron compound to titanium oxide or a substance that becomes titanium oxide by roasting. 500 to 1100 under an inert gas atmosphere or reducing atmosphere.
It is characterized by being fired at a temperature of 0.

In the above invention method, the titanium oxide serving as the raw material V) of the present invention is preferably in the form of fine powder, but instead of titanium oxide,
Titanium hydroxide before the roasting process to produce titanium oxide may be used, or naturally occurring fine mineral powder with a high Ti0z content such as rutile sand may also be used.

The boron or boron compound used in the present invention is as follows. That is, boron is preferably in the form of crystalline or amorphous powder, and boron compounds include boron oxide, alkali metal borate, boron halides such as boron chloride, and organic boron compounds such as poron alcoholade. However, a dehydrated product of boron oxide is particularly preferred. There are no particular restrictions on the means for mixing these boron compounds with the raw material titanium oxide or its equivalent (e.g. titanium hydroxide), and any method may be used as long as the two can be substantially intimately mixed. Optional. However, in general, when using boron or boron compounds in powder form, the particle size should be as small as possible, and in particular, it is better to add some water etc. to these and mix them with the raw material titanium oxide to form a slurry. After that, it is best to spray dry to prepare a homogeneous mixture. In addition, if the raw material boron or boron compound is soluble in a solvent such as water or alcohol, it can be dissolved in a solvent to form a solution and converted into raw material titanium oxide or its equivalent (hereinafter referred to as "titanium oxide, etc."). A method such as dispersion can be adopted. However, even in this case, rather than simply spraying the solution onto titanium oxide, etc., it is preferable to mix the raw material, such as titanium oxide, into the solution and make a slurry, and then use a spray drying method to make a uniform mixture. is preferred.

There is no particular limit to the amount of boron or boron compound added, but it is usually about 0 for boron per 100 parts by weight of titanium oxide.
．． The object of the present invention can be sufficiently achieved by adding about 1 to 15 parts by weight, or about 0.1 to 15 parts by weight in terms of boron in the case of a boron compound.

The reduced titanium oxide of the present invention is prepared by mixing a titanium oxide shade with one or more substances selected from the above-mentioned boron or boron compounds in an inert gas atmosphere or an orthostatic atmosphere.
It can be manufactured by firing at a temperature of 0°C. As will be described in detail later in Examples, for example, titanium oxide may be placed in a closed high-temperature heating furnace and the air inside the system may be removed under reduced pressure, or nitrous scum may be introduced into the furnace and the air may be first flushed with nitrogen. Replace the air and then raise the temperature to a furnace temperature of 500 to 1000°C.
Electrically conductive reduced titanium oxide in which oxygen has been extracted from the titanium oxide crystals can be obtained by reacting the titanium oxide as it is or by introducing hydrogen gas into the furnace and causing the reaction.

, in the present invention, the system in which boron coexists is l500~1
When heated to 000°C, the oxygen atoms that make up the lattice of titanium oxide react with the activated boron and are extracted. A part of the boron oxide generated here forms a solid solution with titanium oxide, but most of it evaporates, so the physical properties of titanium oxide hardly change. Moreover, when hydrogen gas is introduced, oxygen is further extracted by the hydrogen, and reduced titanium oxide can be obtained in a short time. In this case, better results can be obtained if a carbonaceous material is used as the container.

When boron-based compounds are mixed, the atmosphere in the furnace is 500°
From the time when C is exceeded, the boron-based compound decomposes or melts, and boron oxide becomes a solid solution and diffuses in the titanium oxide. Then, hydrogen gas is introduced, and at the same time, boron ions with different ionic valences are extracted. The introduction results in reduced titanium oxide with significant electrical conductivity. In this case as well, better results can be obtained by using a carbon-based material for the container. The reason why the use of carbon-based materials as the reaction vessel produces good results can be explained as the result that the material creates a reducing atmosphere in the furnace. Further, carbon powder may be mixed into titanium oxide in advance.

When boron is used as an additive, the reaction atmosphere may be either an inert gas atmosphere such as nitrogen gas or argon gas, or a reducing atmosphere such as hydrogen gas. On the other hand, when a boron-based compound is used, firing in a reducing atmosphere using a combination of an inert gas and a carbon-based material or hydrogen gas is preferred.

The firing temperature in the method of the present invention is usually 500 to 100
0°C1 is preferably in the range of 600 to 800°C.

Firing time is usually 15 to 120 minutes, preferably 20 to 70 minutes.
range of minutes.

The reduced titanium oxide obtained by the production method of the present invention is a conductive material in the form of *IB powder, and can be sintered to produce a conductive sintered body, and kneaded with a binder to be used in conductive paints and inks. By kneading conductive compounds and adhesives with resins, conductive compounds, sheets, etc. can be obtained by papermaking or blending to obtain conductive fabrics, fibers, and papers, respectively. It can also be suitably used for stone Buddha statues such as cosmetics.

(Example) Examples will be described below, but the examples are merely for explanation and do not indicate the limits of the spirit of the invention.

Example 1 Water was added to 5 g of titanium oxide [manufactured by Wako Tsumugi Kogyo Co., Ltd.] and 0.1 g of boron [manufactured by Wako Tsumugi Kogyo Kogyo Co., Ltd.], mixed, slurried, and spray-dried to form a granular intimate mixture. It was created. This mixture was filled in a graphite crucible and transferred to a siliconite tubular electric furnace. After sealing, nitrogen gas was flowed at room temperature using a flowmeter of 150I111/min for about 1 hour to adjust the atmosphere. The temperature was raised to 500°C.

Next, the introduced gas was changed to water cannula gas, and while hydrogen gas was introduced into the flow at a rate of 120 ml/17 min, it was held at 850°C for about 1 hour, then the electric furnace was turned off and the hydrogen gas was left flowing. It got cold. When the temperature was lowered to 200° C., the introduced gas was switched to nitrogen gas, and the product was taken out of the furnace. The obtained product was reduced titanium oxide with a black color.

Example 2 Water was added to 5 g of titanium oxide (manufactured by the above-mentioned company) and 05 g of boric anhydride (same as above) to form a slurry, and the slurry was then spray-dried to prepare a mixture. The mixture was filled into a 30 ml alloy container and transferred to a silicone tubular electric furnace, and nitrogen gas was added at room temperature at a rate of 151/min. Let it run for about an hour,
Adjusted the atmosphere. After that, while introducing nitrogen scum,
After raising the temperature to 0°C and maintaining the same temperature for about 20 minutes,
The introduced sludge is changed to hydrogen sludge, and the sludge is transferred to the flow meter 120.
The temperature was raised to 900° C. while introducing ml at a rate of 1 minute. Next, after holding at the same temperature for about 1 hour, the electric furnace was turned off, and while hydrogen gas was still being introduced, it was left to cool to 200 ° C., the introduced scum was switched to nitrogen, and after curing to the temperature of the furnace or room temperature, The product was taken out of the furnace. The target product obtained was reduced titanium oxide with a black color.

Example 3 Everything was the same as in Example 1 except that the gas introduced in Example 1 was changed from hydrogen gas to nitrogen gas, and the gas was introduced at a rate of 120 ml/17 minutes while being held at 750'O for about 1 hour.
operated in the same way. In this way, reduced titanium oxide with a black color was obtained.

15 g of dried titanium hydroxide C manufactured by Otsuka Chemical ■ and 0.3 g of boron [manufactured by the above company] were thoroughly mixed, and the mixture was filled into a 30 m1 platinum crucible and transferred to a siliconite tubular electric furnace. After adjusting the atmosphere by flowing nitrogen gas at a flow rate of 150 ml/min for about 1 hour at room temperature, the temperature was raised to 5000 C while continuing to introduce the gas. Next, the introduced gas was switched to hydrogen gas, and the same gas was introduced at a flow rate of 120 ml/min while being held at 900°C for 50 minutes.The electric furnace was then turned off and cooled to 200°C while hydrogen gas was introduced. . Next, the introduced gas was switched to nitrogen gas, and after the temperature of the furnace was lowered to room temperature, the contents of the crucible were taken out of the furnace. The obtained reduced titanium oxide was black in color.

Example 5 Dry titanium hydroxide (manufactured by the above company) 5g and anhydrous borax 05g
Water was added to form a slurry, and then spray-dried to create a mixture. This mixed body was filled in a graphite crucible and transferred to a siliconite tubular electric furnace, and after introducing nitrogen scum to adjust the atmosphere in the furnace, the temperature was raised while introducing the scum at a rate of 150 m 17 minutes. I let it happen. When the furnace temperature reached 500'O, the introduced gas was switched to hydrogen gas, and the furnace temperature was maintained at 850°C for about 1 hour. Next, the power was turned off, and the crucible was allowed to cool while flowing hydrogen gas. When the furnace temperature decreased to 200° C., the introduced gas was changed to nitrogen gas, and after the furnace temperature decreased to room temperature 1, the crucible was taken out of the furnace. In this way, reduced titanium oxide with a black color was obtained.

Each of the five-element titanium oxides 9 obtained in Examples 1 to 5 of Nyukasa Yu
After thoroughly mixing 0 parts by weight and 10 parts by weight of liquid paraffin in a mortar, the inner diameter is 10 mm and the length is 20111! 50 with + mold
After applying silver paste to both sides of the molded product obtained by pressure molding for 10 minutes under a pressure of Kg/c + w2, the conductivity was measured using a digital multimeter [manufactured by Tagada Riken], and the volume resistivity was determined. was calculated according to the formula below. The results are shown in Table 1 below.

(Ω・cIll) Interelectrode hole 121 (cm) Table 1 (Effects of the invention)

Claims (5)

[Claims] (1) One or more types of boron or boron compounds are added to titanium oxide or a substance that becomes titanium oxide by roasting, and the mixture is fired at a temperature of 500 to 1100°C in an inert gas atmosphere or a reducing atmosphere. A method for producing reduced titanium oxide. (2) The manufacturing method according to claim 1, wherein the boron is crystalline boron or amorphous boron. (3) The method according to claim 1, wherein the boron compound is boric acid, borax, or a boron-based organometallic compound. (4) The manufacturing method according to claim 1, wherein the inert gas atmosphere is a nitrogen or argon atmosphere. (5) The manufacturing method according to claim 1, wherein the reducing atmosphere is a hydrogen gas atmosphere or a carbon-filled atmosphere.