JPH0478735B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention has a tetragonal tunnel structure and has a general formula A _x Ga _16+x Ti _16-x O ₅₆ (wherein A: K, Rb and Cs,
x: 0.5 to 2) The present invention relates to a method for producing fibers or membranes of a compound having a composition represented by x: 0.5 to 2).

(Prior art) General formula A _x Ga _16+x Ti _16-x O ₅₆ (However, A: K, Rb
Compounds with a tetragonal tunnel structure represented by Cs, x: 0.5-2) have excellent heat resistance and heat insulation properties, and are therefore useful as heat-resistant and heat-insulating materials, and are also useful as reinforcing materials for plastics, metals, cement, etc. It is also used as

Conventionally, the flux method has been known as a method for producing this compound (Japanese Patent Application No. 124095/1982).
This method uses alkali molybdate as a flux, melts it at high temperature, and then slowly cools it to grow a fibrous single crystal through a dissolution-precipitation reaction.

On the other hand, as methods for producing polycrystalline fibers for inorganic fibers such as alumina fibers and zirconia fibers, methods such as a precursor polymer method, a slurry method, an inorganic salt method, and a sol method have been known, and it is difficult to apply them to the production of the above compounds. can also be considered. First, representative examples of these methods are as follows.

The precursor polymer method is a method in which ertel silicate is mixed into a viscous solution containing polyaluminoxane, an inorganic polymer having a main chain consisting of -Al-O-, followed by dry spinning and firing.

The slurry method _{uses Al2O3} fine powder and a small amount of _MgCl2 .
Al ₂ (OH) ₅ Cl・ as a binder component in 6H ₂ O
In this method, 2.2H ₂ O is added to form a viscous slurry, which is then dry spun and fired.

The inorganic salt method is a method in which a water-soluble organic polymer such as polyethylene oxide or PVA is added to an aqueous solution of aluminum salt, and water-soluble polysiloxane is further mixed to form a viscous liquid, which is then blown out from a nozzle and fired.

The sol method is a method in which silica gel and boric acid are added to alumina sol containing ions such as HCOO and CH ₃ COO to form a viscous liquid, which is then spun and fired.

(Problems to be Solved by the Invention) However, both the flux method and the method for producing polycrystalline fibers have the following problems.

First, the flux method has the problem that not only is it impossible to obtain long fibers, but also that expensive flux is used, requiring a recovery process, which increases manufacturing costs.

On the other hand, in the case of manufacturing polycrystalline fibers, the spinning solution is used to spin fibers, so the spinning stock solution is important, and the physical properties of the solution such as viscosity, spinnability, uniformity, and stability are important. In addition to these factors, it is also important that the spinning stock solution is easy to produce and has excellent spinnability.

From this point of view, when the various methods described above are applied, firstly, although the precursor polymer method has high uniformity, it is difficult to control the manufacturing process for producing the spinning dope. In the sol-gel method, it is difficult to control the concentration because precipitation and turbidity occur or the viscosity increases rapidly during this concentration step. Since the inorganic salt method uses a water-soluble organic polymer to provide the viscosity that gives the fiber form, the stock solution may lack stability, such as gelation during the preparation stage. In addition, the slurry method is a so-called heterogeneous system, and the viscosity, amount added, and dispersion state of the solid particles constituting the spinning stock solution subtly affect spinnability, making it difficult to control.

The present invention provides fibers of a compound having a tetragonal tunnel structure represented by the general formula A _x Ga _16+x Ti _16-x O ₅₆ (A: K, Rb and Cs, x: 0.5 to 2) or When producing membrane-like products, it solves the problems of the spinning dope in the conventional method, makes it easy to adjust the viscosity of the spinning dope, and has excellent spinnability, uniformity, and stability, and good spinnability. The purpose is to provide a method that is easy to manufacture.

(Means for Solving the Problem) In order to achieve the above object, the present inventors have
We focused on the advantage of applying the manufacturing method of polycrystalline fibers rather than the flux method, which uses expensive fluxes, and as a result of intensive research to solve the unique problems, we developed a specific material as a composition raw material. It was discovered that a viscous liquid suitable for spinning can be obtained by adding it to a specific organic acid aqueous solution at a predetermined ratio, dissolving and concentrating it, and that the desired purpose can be achieved by extruding, molding, and baking this liquid. , completed the present invention.

That is, the method for producing fibers or membranes of the compound represented by A _x Ga _16+x Ti _16-x O ₅₆ according to the present invention can be summarized as follows: A _x Ga _16+x Ti _16-x O ₅₆ ( However, A:
When producing a compound having a tetragonal tunnel structure represented by K, Rb, and Cs, x: 0.5 to 2), titanium alkoxide is used as the Ti component of the raw material, and Ga
Using the nitrate of the component as the component and the carbonate of the component as the A component, each raw material blended in the composition ratio shown by the above general formula is added to the total amount of the A component, Ti component, and Ga component. It is added to an aqueous solution of single or mixed organic acids such as citric acid and tartaric acid in a molar amount or more of 0.85 times or more, dissolved and concentrated to obtain a spinning solution, which is then spun into a fibrous or film-like material.
By firing at ~1550℃, A _x Ga _16+x Ti _16-x
Formations consisting of a single O ₅₆ phase can be obtained, or A _x Ga _16+x Ti _16-x O ₅₆ is the main formed phase, with TiO ₂ (rutile) and β-Ga ₂ O The present invention is characterized by obtaining a _two -phase or three-phase mixed molded product in which a small amount of one or both of the three (β-galia) is produced.

The present invention will be explained in detail below.

(Function) First, as a raw material for producing a compound having a composition represented by the above-mentioned general formula A _x Ga _16+x Ti _16-x O ₅₆ and having a tetragonal tunnel structure, the following specific component raw materials are used.

Titanium alkoxide is used as the Ti component. As this titanium alkoxide, for example,
Examples include titanium tetraisopropoxide and titanium tetra-normal butoxide. Incidentally, titanium alkoxide reacts very easily with citric acid and tartaric acid to obtain a transparent and uniform solution, which can be converted into an oxide by firing.

As the Ga component, its nitrate is used because of its availability and ease of handling.

Even if the nitrate is added as a Ga component to the transparent solution thus obtained, the solution will not become non-uniform.

In addition, Ga〓 may form a solid solution with Fe, Cr, and Al.
In this case, these appropriate organic salts, inorganic salts, and alkoxides can be used as raw materials.

In addition, the carbonate is used as component A,
When mixed with an organic acid aqueous solution (described later), it releases CO ₂ and becomes a transparent homogeneous solution.

Each of these raw materials is added to a single or mixed aqueous organic acid solution of citric acid and tartaric acid in a composition ratio according to the above general formula, and is dissolved and concentrated to form a viscous liquid with stringiness.

In this case, the amount of the single or mixed organic acids of citric acid and tartaric acid needs to be at least 0.85 times the molar amount of the total mole of the A component, Ti component, and Ga component. If the amount is less than 0.85 times the mole, the resulting spinning stock solution will become non-uniform, will not exhibit spinnability, and will be difficult to solidify.
Cannot form into fibrous or film-like materials. It is preferable to use water in an amount of 20 to 50 times the total number of moles of component A, Ti component, and Ga component in the aqueous solution of the organic acid.

This will give you a clear and homogeneous solution.
When this is heated and concentrated to a viscosity of about 1 to 100 poise, a viscous liquid that is stringable at 90 to 100°C is obtained. This liquid solidifies as the temperature decreases. Therefore, it is preferable to perform the spinning at 90 to 100°C.

When spinning, a long fiber is obtained using a nozzle, and a film-like material is obtained when extruded through a slit.
Moreover, it can be made into ultra-fine short fibers by extruding it through a thick diameter nozzle and burning and blowing it away with flame.

In addition, when the range of x in the general formula A _x Ga _16+x Ti _16-x O ₅₆ is 0.5≦x≦2.0, there is not much difference in the spinnability, viscosity, etc. of the spinning dope. unacceptable.

The obtained fibrous or film-like material is subjected to water removal,
After heating in air at 700 to 1000°C to decompose and remove organic substances, baking at 1200 to 1550°C yields the desired compound (fiber or film) having a tetragonal tunnel structure. It will be done. However, 1200℃
If it is less than 1550°C, the firing will not be completed, and if it exceeds 1550°C, it will start to melt, which is not preferable.

In addition, when x=1.2 in the general formula A _x Ga _16+x Ti _16-x O ₅₆ , the generated phase obtained by firing is as follows:
A single phase consists of only the compound having a tetragonal tunnel structure, but as x becomes smaller than 1.0, the TiO ₂ (rutile) phase increases in addition to the compound having a tetragonal tunnel structure in the generated phase, and x but
The larger the value is than 1.2, the more β-Ga ₂ O ₃ is present in the generated phase in addition to compounds with a tetragonal tunnel structure.
(β-Gallia) phase increases. The optimum composition range for x is 1.0<x≦1.5, but even when x is in the range of 0.5≦x≦2.0 shown in the above general formula, the basic physical properties for its use are hardly affected.

(Example) Next, examples of the present invention will be shown.

Example 1 This example is an example in which x=1.2 in the general formula A _x Ga _16+x Ti _16-x O ₅₆ and in which citric acid is used as the organic acid.

First, add 21.0 g of titanium tetraisopropoxide to a solution of 28.6 g of citric acid dissolved in 50 ml of distilled water.
was added dropwise and stirred for about half a day to obtain a transparent solution.

Next, 0.41 g of potassium carbonate was gradually added to this solution and stirred until the solution became transparent and uniform. All the above operations were performed at room temperature.

In addition, gallium nitrate nonahydrate (Ga
After adding 35.9 g of (NO ₃ ) ₃ ·9H ₂ O) and stirring at room temperature for a while, the mixture was heated at 100° C. and concentrated until the viscosity reached 100 poise. This was a transparent, uniform, viscous solution, and when it was allowed to cool, its viscosity gradually increased and it had good stringability.

Next, the material in an appropriate viscous state is extruded through a nozzle into a dry atmosphere at room temperature to form a material with a diameter of 5 to 100 μm.
m long fibers were obtained. This fiber was colorless and transparent.

The obtained fibers were dried at 100°C overnight and then heated to 900°C.
The mixture was heat-treated at 1300° C. for 2 hours, and then baked at 1300° C. for 30 hours.

The obtained fibers were composed of a single phase of gallotitanogallate having a tetragonal tunnel structure with a composition of K _1.2 Ga _17.2 Ti _14.8 O ₅₆ .

Furthermore, even if the A component is replaced with K and Rb and Cs are used,
Similar single phase fibers were obtained in each case.

Example 2 In this example, in the general formula A _x Ga _16+x Ti _16-x O ₅₆ ,
This is an example in which x=1.0 and synthesis is performed using citric acid as the organic acid.

First, add 14.8 g of titanium tetraisopropoxide to a solution of 21.8 g of citric acid dissolved in 50 ml of distilled water.
was added dropwise and stirred for about half a day to obtain a transparent solution.

Next, 0.24 g of potassium carbonate was gradually added to this solution and stirred until the solution became transparent and uniform. All the above operations were performed at room temperature.

Further, 24.6 g of gallium nitrate nonahydrate was added thereto, and after stirring at room temperature for a while, the mixture was heated at 100° C. and concentrated until the viscosity reached 100 poise. This was a transparent, uniform, viscous solution, and when it was allowed to cool, its viscosity gradually increased and it had good stringability.

Next, the material in an appropriate viscous state is extruded through a nozzle into a dry atmosphere at room temperature to form a material with a diameter of 5 to 100 μm.
m long fibers were obtained. This fiber was colorless and transparent.

The obtained fibers were dried at 100°C overnight and then heated to 900°C.
The mixture was heat-treated at 1300° C. for 2 hours, and then baked at 1300° C. for 30 hours.

The obtained fiber is K _x Ga _16+x Ti _16-x O ₅₆ (x≒1.2)
The fiber contained gallotitanogallate having a tetragonal tunnel structure and a very small amount of TiO ₂ (rutile).

K _1.5 Ga _17.5 Ti _14.5 by similar raw material preparation method
When prepared to a composition of O ₅₆ , K _x Ga _16+x Ti _16-x O ₅₆
(x≒1.2) composition of gallotitanogallate and β-
A mixed phase fiber of Gallia was obtained.

Furthermore, even if the A component is replaced with K and Rb and Cs are used,
Similar mixed phase fibers were obtained in each case.

Example 3 This example is an example of synthesis using tartaric acid as the organic acid.

First, a solution of 14.2 g of tartaric acid dissolved in 50 ml of distilled water was used as an organic acid aqueous solution, and the following procedure was carried out in the same manner as in Example 2 to prepare a square with a composition of K _x Ga _16+x Ti _16-x O ₅₆ (x≈1.0). Long fibers containing gallotitanogallate having a crystalline tunnel structure and a very small amount of TiO ₂ (rutile) were obtained.

In addition, in the case of tartaric acid, the relationship between compositional variation and synthetic phase was the same as in Examples 1 and 2.

Also, even if the A component is replaced with K and Rb and Cs,
Similar fibers were obtained in each case.

(Effects of the Invention) As described in detail above, according to the present invention, when producing fibers or film-like products of a compound having a tetragonal tunnel structure represented by the general formula, the viscosity of the spinning dope can be adjusted appropriately. It is easy to adjust to a desired product, has excellent spinnability, uniformity, and stability, has good spinnability, and is easy to manufacture.

Therefore, it has the excellent effect that fibers or membranes having the desired composition can be obtained more easily and at lower cost.

Claims (1)

[Claims] 1 General formula A _x Ga _16+x Ti _16-x O ₅₆ (However, A: K,
When producing a compound with a tetragonal tunnel structure represented by Rb and Cs, x: 0.5 to 2), the raw material
Using titanium alkoxide as the Ti component, using the nitrate of this component as the Ga component, and using the carbonate of the component as the A component, each raw material was blended in the composition ratio shown by the above general formula. component, Ti component and
Add to an aqueous solution of single or mixed organic acids such as citric acid and tartaric acid in an amount of 0.85 times the mole or more based on the total amount of Ga components, dissolve and concentrate to obtain a spinning solution, which is then spun to form a fibrous or membrane-like product. After that, 1200～
By firing at 1550℃, A _x Ga _16+x Ti _16-x
1. A method for producing a fiber or film-like product of a compound represented by A _x Ga _16+x Ti _16-x O ₅₆ , characterized in that a formed body consisting of a single O ₅₆ phase is obtained. 2 The phase generated by the firing is A _x Ga _16+x
Ti _16-x O ₅₆ is the main produced phase, and other than that, TiO ₂
The method according to claim 1, wherein the method is a two-phase or three-phase mixed system in which one or both of (rutile) and β-Ga ₂ O ₃ (β-gallia) are produced in small amounts.