JPH0881833A - Method for producing tin oxide fiber - Google Patents

Abstract

PURPOSE: To provide a method for producing a tin oxide fiber, capable of preventing the deformation of a gel fiber due to the breakage and softening of the gel fiber, even when the gel fiber is brought into contact with an atmosphere having a high humidity before the thermal treatment of the gel fiber, and capable of being smoothly transferred to the thermal treatment. CONSTITUTION: The method for producing the (conductive) tin oxide fiber comprises dissolving a tin halide compound such as stannous chloride, a silicon alkoxide such as tetramethoxy silane and, if necessary, a group V element compound such as antimony trichloride in an alcohol such as methanol, spinning the obtained spinning solution in an ammonia atmosphere, or spinning the spinning dope and subsequently bringing the spin fiber into contact with the ammonia atmosphere, and subsequently thermally treating the fiber. The fiber having a prescribed shape can industrially stably be produced in improved productivity.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing tin oxide fibers.

[0002]

2. Description of the Related Art Tin oxide has excellent chemical resistance and heat resistance,
Moreover, it is an excellent material capable of controlling conductivity in a wide range and is used for various purposes. Recently, research is also progressing as a third-order nonlinear optical material.

In a gas sensor, it has been strongly desired to provide tin oxide in a fiber shape from the viewpoint of improving sensitivity and response speed. Further, carbon fibers and the like have been added for the purpose of imparting conductivity to polymer materials,
When carbon is used, there are problems that the material itself cannot be brightened because it is black and that it is very light and easily scattered. For this reason, it has been practiced to add powders of metal fibers and metal oxides. Although metal fibers have high conductivity, they have the drawback that their surface is oxidized or corroded over a long period of time to lower their conductivity. In addition, the conductivity of conventional metal oxide powders is not as high as that of metal fibers, so in order to impart conductivity to polymer materials, a relatively large amount must be added, and the physical properties inherent in polymer materials deteriorate. There was a drawback that caused it. Even tin oxide, which has excellent chemical resistance and heat resistance, has been attempted to be added in the form of powder that imparts conductivity.

By the way, it is known that the effect of imparting conductivity increases as the aspect ratio of the conductivity imparting material increases. For this reason, it has been required to make tin oxide having conductivity into a fiber. However, it has been difficult to manufacture a fiber by the conventional solid-phase reaction method. For this reason, JP-A-60-5997 and JP-A-60-161.
No. 337 and JP-A-60-158199 propose a method for producing tin oxide by a melt precipitation method. However, since these methods require a high temperature of 1000 ° C. or higher and a reaction time of several days, it is possible to produce a very small amount on a laboratory scale, but it has not been industrially produced yet. . Moreover, the shape of the obtained tin oxide fiber is 1 μm or less in diameter, 3 mm or less in length, the aspect ratio is small, and the cross section is often rectangular. Therefore, when used as a composite material, its function can be sufficiently exhibited. However, there was a problem that its use was limited. Furthermore, since the major axis is too small, it is difficult to produce a paper-like material. Further, in order to enhance the reproducibility of physical properties such as conductivity of the obtained composite material, it is important to control the shape and size of the tin oxide whiskers to be added with good reproducibility. However, since it is actually difficult to control the shape of tin oxide whiskers, if the fiber diameter and the length of the tin oxide to be added were to be made uniform, it was only possible to classify what was accidentally produced. Therefore, the whiskers produced by such an inefficient method are extremely expensive and practically unusable.

The present inventors are surprised to find that a solution containing a tin compound and an alcohol as a main component is used without using a tin alkoxide as a raw material, which is unstable and difficult to handle because it is expensive and has a high reaction rate. The spinnability appears in
It was found that a tin oxide fiber can be easily and extremely inexpensively obtained by spinning and heating this, and it has already been proposed (JP-A-4-35287, JP-A-5-117906, JP-A-5-179512).

[0006]

However, in the case of spinning using the above spinning solution, when the gel fiber is exposed to a high humidity atmosphere between the spinning and the heat treatment, the thread shape is not retained and softens. There are cases where the phenomenon of collapse occurs. Therefore, earnest studies were conducted on a method for producing a fiber in which the yarn shape is not destroyed by the humidity in the atmosphere during spinning and / or after spinning.

[0007]

As a result, it was found that contacting the spun gel fiber with an ammonia atmosphere increases the moisture resistance of the gel fiber, and has completed the present invention.

That is, according to the present invention, a method for producing a tin oxide fiber is characterized in that gel fiber spun from a spinning solution prepared by dissolving a tin halide compound in alcohol is brought into contact with an ammonia atmosphere and then heat-treated. Is.

In another invention, a gel fiber spun from a spinning solution prepared by dissolving a tin halide compound and a group V element compound of the periodic table in alcohol is brought into contact with an ammonia atmosphere and then heat treated. It is a characteristic method for producing tin oxide fibers.

Still another invention is characterized in that a gel fiber spun from a spinning solution prepared by dissolving a tin halide compound and a silicon alkoxide in alcohol is brought into contact with an ammonia atmosphere and then heat-treated, which is a tin oxide fiber. Is a manufacturing method. Still another invention is to heat a gel fiber spun from a spinning solution prepared by dissolving a tin halide compound, a silicon alkoxide, and a Group V element compound of the periodic table in alcohol in contact with an ammonia atmosphere. And a method for producing tin oxide fiber.

The alcohol used in the present invention is not limited as long as it dissolves the tin halide compound described below. When these alcohols are represented by the general formula ROH, R is an unsubstituted alkyl group such as methyl group, ethyl group, propyl group, butyl group, octyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 2-hydroxyethyl group, 1-methoxy-2 group. -Propyl group, methoxyethoxyethyl group, 2
Examples include substituted alkyl groups such as -phenylethyl group and phenylmethyl group, unsubstituted alkenyl groups such as allyl group, and substituted alkenyl groups such as 2-methyl-2-propenyl group and 3-methyl-3-butenyl group.

Specific examples of the substituents in the above-mentioned substituted alkyl group, substituted alkenyl group or substituted aryl group include alkoxy groups such as methoxy group and ethoxy group, hydroxyl group, phenyl group and the like which are found in the above-mentioned specific examples of R. In addition to the aryl group, the alkyl group such as a methyl group and an ethyl group, a halogen atom such as an amino group, a cyano group, a Cl atom, a Br atom, an I atom and an F atom.

Illustrating these alcohols as specific examples,
Methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, octyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol, 1-methoxy-2-propyl alcohol,
Methoxyethoxyethanol, 2-phenylethyl alcohol, benzyl alcohol, allyl alcohol, 2-methyl-2-propen-1-ol, 3-methyl-3-buten-1-ol and the like can be mentioned. In particular, methyl alcohol and ethyl alcohol are preferable because of high solubility of the tin halide compound. The above alcohol is usually used alone, but the reactivity with the tin halide compound,
Alternatively, a mixture of two or more alcohols can be used to control the solubility of the tin halide compound.

The halogen of the tin halide compound used in the present invention is Cl, Br, I or F atom. Among these tin halide compounds, tin chloride and tin bromide are preferable in terms of price and stability. Specifically, SnC
l ₂ , SnCl ₂ .2H ₂ 0, SnBr ₂ , SnI ₂ , Sn
F _{2 and the} like, and particularly SnBr ₂ , SnCl ₂ .2H ₂
O and SnCl ₂ are preferably used. Further, the tin halide compound modified with an organic compound such as Sn (CH ₃ ) ₂ Cl ₂ can also be used.

The blending ratio of the tin halide compound and alcohol is not particularly limited as long as the tin halide compound is uniformly dissolved in the alcohol. However,
If the proportion of the tin halide compound is too low, it does not show spinnability, so it is necessary to concentrate it considerably.
Is wasted. If the tin halide compound concentration is too high, precipitation will occur and a uniform spinning solution cannot be obtained. Therefore, the tin halide compound used and the alcohol
The mixing ratio varies depending on the kind of the alcohol, but generally, the molar ratio of the tin halide compound to the alcohol is preferably 0.02 to 0.5. After blending in this ratio to form a transparent and uniform solution, alcohol is further evaporated to concentrate the solution to obtain a spinning solution having a desired viscosity.

In the present invention, a compound of Group V element of the periodic table (hereinafter referred to as a compound of Group V) may be optionally contained in order to enhance the conductivity of the obtained tin oxide fiber. The group V compound is finally converted into an oxide by the heat treatment described below and is solid-dissolved in tin oxide.

Examples of the Group V compound include compounds of Group V elements such as vanadium compounds, niobium compounds, tantalum compounds, antimony compounds, and bismuth compounds.

Specifically, as the vanadium compound, V
Br ₃ , VCl ₂ , VCl ₃ , VCl ₄ , VOBr ₂ , VO
Br ₃ , VOCl ₃ , VF ₃ , VF ₄ , VF ₅ , VI ₃ 6H ₂
Examples of the niobium compound include NbCl ₅ , NbBr ₅ , NbF ₅ , and NbOC.
l ₃ , alkoxides of niobium, tantalum compounds such as TaBr ₅ , TaCl ₅ and tantalum alkoxides, and antimony compounds such as SbCl ₃ and SbC.
Examples include l ₅ , SbBr ₃ , antimony oxychloride, or antimony alkoxide, and examples of the bismuth compound include BiCl ₃ , BiI ₃ , and bismuth alkoxide.

When it is desired to impart conductivity to the tin oxide fiber, the compounding ratio of the Group V compound is preferably 0.1 to 25 mol% with respect to tin oxide in terms of oxide. If the ratio is too low, the tin oxide fiber obtained will have low conductivity, and if it is too high, the effect of imparting conductivity will be low.

In the present invention, it is preferable to add a silicon alkoxide to the spinning solution in order to carry out spinning stably and to enhance the mechanical strength of the obtained fiber. Such silicon alkoxide of the general formula _{Si (OR A) 4, R} B Si (OR A) 3, R B R C Si
_A silicon alkoxide represented by (OR _A ) ₂ is used. Here, R _A , R _B , and R _C are each a linear or branched alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group; an ethenyl group, a propenyl group, a butenyl group, and a pentenyl group. A linear or branched alkenyl group such as a group; an aryl group such as a phenyl group.

Specific examples of the silicon alkoxide include tetramethoxysilane, tetraethoxysilane,
Tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, propyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, n-
Octadecyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, amyltriethoxysilane, phenyltriethoxysilane, n-octyltriethoxysilane, n-octadecyltriethoxysilane, n-dodecyltriethoxysilane, methyltributoxysilane , Ethyltributoxysilane, ethyltripropoxysilane, vinyltriethoxysilane, allyltriethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, vinylmethyldiethoxysilane, diethyldimethoxysilane, ethylmethyldiethoxysilane and the like.

By adding these silicon alkoxides, fibers having a large major axis can be spun relatively stably even in a high humidity atmosphere. In addition, the gel fiber immediately after spinning is less likely to be softened and easily broken, which makes the handling very easy.
Furthermore, the mechanical strength of the finally obtained fiber is improved. The addition amount of these silicon alkoxides is preferably 0.01 to 30% by weight with respect to the tin halide compound. If the addition amount is less than 0.01% by weight, a sufficient effect cannot be obtained. If it exceeds 30% by weight,
This is not preferable because the silica component in the fiber increases and the conductivity decreases. However, when high conductivity is not required, silicon alkoxide may be further added.

The method for dissolving the tin halide compound, the Group V compound, and the silicon alkoxide and alcohol is
There is no particular limitation. A method in which alcohol is added dropwise to a mixture of a tin halide compound, a silicon alkoxide, and a Group V compound, which is added as needed, with stirring, or a tin halide compound, a silicon alkoxide, and, if necessary, alcohol is added to the alcohol with stirring. Group V compound at the same time,
Alternatively, a method of sequentially dissolving can be used.

In order to improve the stability of the spinning solution of the present invention, a compound having two or more carboxyl groups such as acetylacetone, ethyl acetoacetate, diethyl malonate, etc. can be appropriately contained as a tin complexing agent. .

The spinning method is not particularly limited, and a conventionally known spinning method can be used. For example, a method of extruding a spinning solution from a spinning nozzle can be used. The major axis, the diameter, etc. of the obtained fiber can be arbitrarily controlled by adjusting the viscosity of the spinning solution, the nozzle diameter, the speed at which the spinning solution is extruded from the spinning nozzle, and the like. The unheated fibers spun from the spinning solution are called gel fibers.

In the present invention, it is important to bring the gel fiber into contact with an ammonia atmosphere in order to enhance the stability of the gel fiber after spinning to humidity. The addition of silicon alkoxide to the spinning solution improves the stability of the gel fiber after spinning to humidity, but the contact with an ammonia atmosphere further increases the stability to humidity. That is, by treating the gel fiber in this ammonia atmosphere, the fiber shape is stably maintained even if the gel fiber is brought into contact with a high-humidity atmosphere until the heat treatment to be described later, so that the handling becomes extremely easy, and from the spinning step It enables smooth transition to the heat treatment process.

The method of contacting with an ammonia atmosphere is not particularly limited. For example, a method of contacting with an ammonia atmosphere immediately after spinning by spinning in an ammonia atmosphere, or a method of contacting with an ammonia atmosphere after spinning in air with low humidity, such as a method of not contacting with high humidity before contacting with an ammonia atmosphere If so, it can be used without any limitation.

As the ammonia atmosphere, pure ammonia gas, diluted ammonia gas obtained by diluting the ammonia gas with air, nitrogen, oxygen gas, or the like, or ammonia gas evaporated from aqueous ammonia is appropriately adopted. The ammonia concentration in the ammonia atmosphere is not particularly limited. When the ammonia concentration is low, the contact may be for a long time, and when the ammonia concentration is high, the contact may be for a short time. Generally, an ammonia atmosphere with a concentration of 0.02% to 5% is used.

Although the present inventors cannot fully explain why the moisture resistance of the gel fiber is improved by bringing it into contact with an ammonia atmosphere, the halogen contained in the gel fiber is trapped by the reaction with ammonia. It is presumed that it is because the hygroscopicity is lowered by being removed or removed.

The heat treatment of the gel fiber obtained by the treatment with the ammonia atmosphere removes the organic solvent such as alcohol or water from the gel fiber to strengthen the skeleton of the fiber, and in some cases, at a temperature for further crystallization. Done. The gel fiber as spun from the spinning solution does not show sufficient mechanical strength as it is. The mechanical strength is developed by heating the gel fiber.
The heat treatment temperature is not particularly limited as long as it is within a temperature range capable of imparting mechanical strength to the obtained fiber. When the heat treatment temperature is low, alcohol, water, etc. remain in the fiber, so that sufficient mechanical strength does not occur. On the other hand, if the heat treatment temperature is too high, the decomposition of tin oxide will proceed, or the crystal grains in the fiber will grow too much and the strength will decrease. For the above reason, the heat treatment temperature is preferably in the range of 250 to 1550 ° C. More preferably, heat treatment at a temperature of 300 to 1500 ° C. is preferable.

When it is desired to add a Group V compound to improve the conductivity of the obtained fiber, heat treatment is also necessary. The gel fiber as it is spun from the spinning solution is an insulator as it is, and conductivity is exhibited by heating the gel fiber. The heat treatment temperature is not particularly limited as long as it is within a temperature range capable of imparting conductivity to the obtained fiber. Generally, when the heat treatment temperature is low, organic substances such as alcohol, water, etc. remain in the fiber, and the Group V compound does not form an oxide and does not form a solid solution with tin oxide, resulting in poor conductivity. Does not happen. If the heat treatment temperature is too high, the group V compound in the fiber is volatilized to lower the conductivity, the decomposition of tin oxide proceeds, the crystal grains in the fiber grow too much, and the strength decreases. Occurs. Therefore, the heat treatment temperature is 2
A temperature range of 50 ° C to 1550 ° C is preferred. More preferably, the heat treatment is preferably performed at a temperature of 300 ° C to 1500 ° C.

The heat treatment is usually carried out in air, but when it is desired to obtain a fiber having particularly high conductivity, the heat treatment is carried out in a reducing atmosphere such as nitrogen, argon, hydrogen or a mixed gas of argon and hydrogen, or in vacuum. Processing can be performed.

Further, in the heat treatment, it is desirable to remove the volatile components such as water and alcohol present in the gel fiber by drying in order to obtain a good tin oxide fiber. Such drying may be performed at the same time as the heat treatment, but it is preferable to perform the drying before the heat treatment in order to obtain a good fiber. In these cases, the drying temperature is preferably as low as possible in order to prevent the resulting fiber from cracking,
When an alcohol having a high boiling point is used as the solvent, if it is too low, it takes a long time to dry and is not effective. Generally, the drying temperature is preferably in the range of room temperature to 300 ° C.

The specific resistance value of the conductive tin oxide fiber obtained from the spinning solution containing the Group V compound of the present invention is
It varies greatly depending on the kind of the Group V compound, the addition amount, the firing atmosphere, the firing temperature, etc., but normally 10 ³ to 10 ^-1 Ω.
It can take the value of cm.

Also obtained by the present invention (conductive)
The tin oxide fiber may be crystalline or amorphous, but crystalline is preferable from the viewpoint of conductivity.

[0036]

According to the method of the present invention, even if the gel fiber is brought into contact with a high humidity atmosphere before the heat treatment, the gel fiber does not soften and lose its shape, so that the next heating step can be moved extremely smoothly. Became. As a result,
Industrially stable operation became possible and productivity improved.

[0037]

EXAMPLES The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 10 g (0.05 mol) of stannous chloride (SnCl ₂ ) was dissolved in 100 ml (2.47 mol) of methanol to give a uniform and transparent solution. This solution was concentrated to give a highly viscous spinning solution. The spinning solution was extruded from a nozzle by applying pressure and continuously wound around a drum in an atmosphere having an ammonia concentration of 5000 ppm. The obtained fiber was left in the atmosphere at room temperature for 1 day, then heated to 120 ° C. at a rate of 2 ° C./min, and kept at that temperature for 30 minutes. Then, the temperature was raised to 500 ° C. at a rate of 10 ° C./min, and the temperature was maintained for 30 minutes to perform heat treatment. The average number of fibers obtained is 15
As a result of X-ray diffraction, it was confirmed to be composed of polycrystalline tin oxide having a diameter of μm. Fiber obtained
The average specific resistance was 8 × 10 ⁴ Ω · cm. The tensile strength of the fiber was 11 MPa on average. Place the spun gel fiber in an atmosphere with relative humidity of 85%.
After leaving for a while, the fiber shape was maintained without softening.

Example 2 10 g (0.05 mol) of stannous chloride (SnCl ₂ ) and 1 g (0.004) of antimony trichloride (SbCl ₃ ).
(Mol) was dissolved in 100 ml (2.47 mol) of methanol to form a uniform and transparent solution. This solution was concentrated to give a highly viscous spinning solution. The spinning solution was extruded from a nozzle by applying pressure and continuously wound around a drum in an atmosphere having an ammonia concentration of 5000 ppm. The obtained fiber was left in the atmosphere at room temperature for 1 day, then heated to 120 ° C. at a rate of 2 ° C./min, and kept at that temperature for 30 minutes. 10 ° C /
The temperature was raised to 500 ° C. at a rate of min, and the temperature was maintained for 30 minutes for heat treatment. The obtained fibers had an average diameter of 15 μm, and it was confirmed by fluorescent X-ray analysis that antimony was present in the fibers according to the charged composition. In addition, as a result of X-ray diffraction, it was confirmed that there were peaks corresponding to a plurality of crystal planes of tin oxide, and that peaks of antimony were not seen in the oxides and the like, and that antimony was in solid solution in tin oxide. The specific resistance of the obtained fiber was 8 × 10 ⁻¹ Ω · cm on average. The tensile strength of the fiber was 6 MPa on average. The gel fiber after spinning was left for 1 hour in an atmosphere of relative humidity of 85%, but the fiber shape was maintained without softening.

Example 3 10 g (0.05 mol) of stannous chloride (SnCl ₂ ) and 1 g (0.004) of antimony trichloride (SbCl ₃ ).
(Mol) was dissolved in 100 ml (2.47 mol) of methanol to form a uniform and transparent solution. Thereafter, 1.14 g (0.0075 mol) of tetramethoxysilane was added and dissolved to obtain a uniform solution. This solution was concentrated to give a highly viscous spinning solution. The spinning solution was extruded from a nozzle by applying pressure and continuously wound around a drum in an atmosphere having an ammonia concentration of 5000 ppm. The obtained fiber was left in the atmosphere at room temperature for 1 day, then heated to 120 ° C. at a rate of 2 ° C./min, and kept at that temperature for 30 minutes. Then, the temperature was raised to 500 ° C. at a rate of 10 ° C./min, and the temperature was maintained for 30 minutes to perform heat treatment. The obtained fibers have an average of 15 μm
It was confirmed that antimony and silica were present in the fiber according to the charged composition by fluorescent X-ray analysis. Further, as a result of X-ray diffraction, it was confirmed that it had a peak of tin oxide, and that the peak of antimony was not found in the oxide thereof and was dissolved in tin oxide.
The specific resistance of the obtained fiber was 1 Ω · cm on average. The tensile strength of the fiber is 40 MPa on average.
Met. The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was maintained without softening.

Example 4 Stannous bromide (SnBr ₂ ) 13.9 g (0.05 mol), antimony trichloride (SbCl ₃ ) 1 g (0.00
4 mol) was dissolved in 100 ml (2.47 mol) of methanol to form a uniform and transparent solution, and 1.14 g (0.0075 mol) of tetramethoxysilane was added and dissolved to obtain a uniform solution. . This solution was concentrated to give a highly viscous spinning solution. The spinning solution was extruded from a nozzle by applying pressure and continuously wound around a drum under an atmosphere having an ammonia concentration of 1%. The obtained fiber was left at room temperature for 1 day, then heated to 120 ° C. at a rate of 2 ° C./min, and kept at that temperature for 30 minutes. Then 5 at a rate of 10 ° C / min
The temperature was raised to 00 ° C., and the temperature was maintained for 30 minutes for heat treatment. The obtained fiber had an average diameter of 15 μm, and it was confirmed by fluorescent X-ray analysis that antimony and silica were present in the fiber according to the charged composition. Further, as a result of X-ray diffraction, it was confirmed that it had a peak of tin oxide, and that the peak of antimony was not found in the oxide thereof and was dissolved in tin oxide. The specific resistance of the obtained fiber was 1 Ω · cm on average. The tensile strength of the fiber was 40 MPa on average. The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was maintained without softening.

Example 5 Stannous chloride dihydrate (SnCl ₂ .2H ₂ 0) 11.3
g (0.05 mol) and antimony trichloride (SbCl ₃ )
1 g (0.004 mol) was added to 100 ml of methanol (2.
47 mol) to give a uniform and transparent solution. After that, 1.127 g of ethyltrimethoxysilane (0.0075
Mol) was added and dissolved to obtain a uniform solution. This solution was concentrated to give a highly viscous spinning solution. This spinning solution was pressed out from a nozzle and continuously wound around a drum under an atmosphere with an ammonia concentration of 5%. Fiber obtained
After being left at room temperature for 1 day, the temperature was raised to 120 ° C. at a rate of 2 ° C./min and kept at that temperature for 30 minutes. 10 ° C /
The temperature was raised to 500 ° C. at a rate of min, and the temperature was maintained for 30 minutes for heat treatment. The obtained fibers have an average diameter of 15 μm, and by fluorescent X-ray analysis,
It was confirmed that antimony and silica were present in the fiber according to the charged composition. Further, as a result of X-ray diffraction, it was confirmed that it had a peak of tin oxide, and that the peak of antimony was not found in the oxide thereof and was dissolved in tin oxide. The specific resistance of the obtained fibers is 1 on average.
It was Ω · cm. The tensile strength of the fiber was 40 MPa on average. The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was maintained without softening.

Example 6 Instead of methanol, 100 ml of ethanol and SbC were used.
Example 3 was repeated except that 1.13 g of Sb (OC ₂ H ₅ ) ₃ was used instead of 1 g of l _{3 and} 2.22 g (0.015 mol) of dimethyldiethoxysilane was used instead of tetramethoxysilane. It was By fluorescent X-ray analysis of the obtained fiber, it was confirmed that antimony and silica were present in the fiber according to the charged composition. Also, X
It was confirmed by line diffraction that the tin oxide was crystalline tin oxide in which antimony was solid-dissolved. The average specific resistance of the obtained fibers was 8 × 10 ¹ Ω · cm. The tensile strength of the fiber was 90 MPa on average. The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was retained.

Example 7 Example 4 was repeated except that 0.741 g (0.005 mol) of vinyltrimethoxysilane was used instead of tetramethoxysilane. By fluorescent X-ray analysis of the obtained fiber, it was confirmed that antimony and silica were present in the fiber according to the charged composition. In addition, as a result of analysis by X-ray diffraction, it was confirmed to be crystalline tin oxide in which antimony was solid-dissolved. The specific resistance of the obtained fiber was 1 Ω · cm on average. Also,
The tensile strength of the fiber was 30 MPa on average.
The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was retained.

Example 8 Using 2-ethoxyethanol in place of methanol and adjusting the ammonia concentration in the spinning atmosphere to 200 pp
The same procedure as in Example 3 was repeated except that the length was changed to m. By fluorescent X-ray analysis of the obtained fiber, it was confirmed that antimony and silica were present in the fiber according to the charged composition. In addition, as a result of analysis by X-ray diffraction, it was confirmed to be crystalline tin oxide in which antimony was solid-dissolved. The specific resistance of the obtained fiber was 1 Ω · cm on average. The average tensile strength of the fiber is 40M.
It was Pa. Relative humidity 85 after spinning gel fiber
%, The fiber shape was retained.

Example 9 Instead of 1 g (0.004 mol) of antimony trichloride (SbCl ₃ ), 0.945 g (0.004) of TaCl ₅ was used.
The same procedure as in Example 3 was performed except that 26 mol) was used. Fluorescent X-ray analysis of the obtained fiber confirmed that tantalum and silica were present in the fiber according to the charged composition. Moreover, as a result of X-ray diffraction analysis, it was confirmed to be crystalline tin oxide in which tantalum was solid-dissolved. The specific resistance of the obtained fiber is 3 × 1 on average.
It was 0 ³ Ω · cm. The tensile strength of the fiber was 40 MPa on average. The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was retained.

Example 10 Instead of 1 g (0.004 mol) of antimony trichloride (SbCl ₃ ), 0.712 g (0.004 of NbCl ₅ ) was used.
The same procedure as in Example 3 was performed except that 26 mol) was used. Fluorescent X-ray analysis of the obtained fiber confirmed that niobium and silica were present in the fiber according to the charged composition. As a result of X-ray diffraction analysis, it was confirmed to be crystalline tin oxide having niobium as a solid solution. The specific resistance of the obtained fiber is 3 × 1 on average.
It was 0 ³ Ω · cm. The tensile strength of the fiber was 40 MPa on average. The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was retained.

Example 11 Example 3 was repeated except that antimony trichloride was not added. Fluorescent X-ray analysis of the obtained fiber confirmed that silica was present in the fiber according to the charged composition. As a result of X-ray diffraction, it was confirmed to be crystalline tin oxide. The specific resistance of the obtained fiber was 8 × 10 ⁵ Ω · cm on average. Also,
The tensile strength of the fiber was 40 MPa on average.
The gel fiber after spinning was left for 2 hours in an atmosphere of relative humidity of 85%, but the fiber shape was retained. Example 12 Example 3 was repeated, except that the gel fiber obtained was spun in the atmosphere with a relative humidity of 55%, left in contact with an atmosphere having an ammonia concentration of 200 ppm, and then heat-treated.
I went the same way. The obtained fiber had an average diameter of 15 μm, and it was confirmed by fluorescent X-ray analysis that antimony and silica were present in the fiber according to the charged composition. Further, as a result of X-ray diffraction, it was confirmed that it had a peak of tin oxide, and that the peak of antimony was not found in the oxide thereof and was dissolved in tin oxide. The specific resistance of the obtained fiber was 1 Ω · cm on average.
The tensile strength of the fiber was 40 MPa on average. The gel fiber after being brought into contact with the ammonia atmosphere was left for 2 hours in an atmosphere having a relative humidity of 85%, but the fiber shape was maintained without softening.

Comparative Example 1 The procedure of Example 1 was repeated, except that the fiber was spun in the atmosphere and was not contacted with the ammonia atmosphere. The obtained fibers had an average diameter of 15 μm, and X-ray diffraction confirmed that the fibers were tin oxide. The specific resistance of the obtained fibers was 8 × 10 ⁴ Ω · cm on average. The tensile strength of the fiber was 11 MPa on average. When the gel fiber immediately after spinning was left in an atmosphere having a relative humidity of 75%, it was softened after 5 minutes and the fiber shape was broken.

Comparative Example 2 The procedure of Example 2 was repeated, except that the spinning was carried out in the air and not contacted with the ammonia atmosphere. The obtained fibers had an average diameter of 15 μm, and it was confirmed by fluorescent X-ray analysis that antimony was present in the fibers according to the charged composition. Further, as a result of X-ray diffraction, it was confirmed that antimony did not show peaks such as oxides thereof and was solid-dissolved in tin oxide. The specific resistance of the obtained fiber was 8 × 10 ⁻¹ Ω · cm on average. The tensile strength of the fiber was 6 MPa on average. When the gel fiber after spinning was left in an atmosphere of relative humidity of 75% for 5 minutes, it was softened and the fiber shape was broken.

Comparative Example 3 The procedure of Example 3 was repeated, except that the fiber was spun in the atmosphere and was not contacted with the ammonia atmosphere. The obtained fibers have an average diameter of 15 μm, and by fluorescent X-ray analysis,
It was confirmed that antimony and silica were present in the fiber according to the charged composition. Further, as a result of X-ray diffraction, it was confirmed that it had a peak of tin oxide, and that the peak of antimony was not found in the oxide thereof and was dissolved in tin oxide. The specific resistance of the obtained fiber is 1Ω on average.
・ It was cm. The tensile strength of the fiber was 40 MPa on average. When the gel fiber immediately after spinning was left in an atmosphere of relative humidity of 85%, it softened after 1.5 hours and the fiber shape collapsed.

Comparative Example 4 The same procedure as in Example 11 was carried out except that it was not contacted with the ammonia atmosphere. Fluorescent X-ray analysis of the obtained fiber confirmed that silica was present in the fiber according to the charged composition. As a result of X-ray diffraction, it was confirmed to be crystalline tin oxide. The specific resistance of the obtained fiber was 8 × 10 ⁵ Ω · cm on average. The tensile strength of the fiber is 40 MPa on average.
Met. When the gel fiber after spinning was left in an atmosphere of relative humidity of 85%, it softened after 1.5 hours and the fiber shape was broken.

Claims (4)

[Claims] 1. A method for producing a tin oxide fiber, which comprises subjecting a gel fiber spun from a spinning solution obtained by dissolving a tin halide compound to alcohol to an ammonia atmosphere and then heat-treating the gel fiber. 2. A gel fiber spun from a spinning solution obtained by dissolving a tin halide compound and a group V element compound of the periodic table in alcohol is brought into contact with an ammonia atmosphere and then heat-treated. Manufacturing method of tin oxide fiber. 3. A gel fiber spun from a spinning solution prepared by dissolving a tin halide compound and a silicon alkoxide in alcohol is contacted with an ammonia atmosphere,
A method for producing a tin oxide fiber, which comprises heat treatment. 4. A gel fiber spun from a spinning solution prepared by dissolving a tin halide compound, a silicon alkoxide, and a Group V element compound of the periodic table in alcohol is brought into contact with an ammonia atmosphere and then subjected to heat treatment. A method for producing a tin oxide fiber, which is characterized.