JPS6249362B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing inorganic fibers. More specifically, the present invention relates to a method for producing inorganic fibers from polymetalloxane having phenoxy groups. In particular, the present invention involves spinning a polymetalloxane having a phenoxy group in its side chain, subjecting it to infusible treatment as necessary, and then firing it to produce inorganic fibers, particularly alumina fibers and alumina-silica fibers. It is about the method. In recent years, as a result of technological developments in many industrial fields including the aerospace industry, materials with properties superior to those of conventional materials, such as heat resistance at high temperatures and high mechanical properties, have been developed. Development is strongly desired. One way to improve the physical properties of such materials is to use conventional materials such as carbon fiber, tungsten, molybdenum, metal fibers such as steel, and the surface of tungsten fibers with boron.
Commonly used methods include composite reinforcement using composite fibers covered with silicon carbide, polycrystalline fibers such as alumina and zirconia, and whiskers such as silicon carbide. Metal oxide fibers, which are one of these strong materials for composite materials, can be used in high-temperature oxidizing atmospheres where carbon fibers and metal fibers cannot be used, and are generally excellent at high temperatures due to their high melting points. It has characteristics such as not losing its mechanical properties, and is expected to be used not only as a composite reinforcing material but also in an extremely wide range of industrial fields. Various methods have been proposed for producing such metal oxide fibers (for example, Japanese Patent Publication No. 40-26213, Japanese Patent Publication No. 45-9896).
Publication No. 44-24690, Special Publication No. 47-718
Publication No. 48-30327, Special Publication No. 51-
18965, etc.). Previously, the present inventors proposed a method for producing inorganic fibers such as alumina, alumina-silica, titania, and zirconia fibers using polymetalloxane as a starting material (Japanese Patent Publication No. 12736/1983,
-13768 Publication, JP-A-49-124336 Publication, same.
No. 50-136424, No. 18726). In the above method, the metal oxide content of the precursor fiber is high, and therefore the fiber after firing is dense, resulting in high strength and high elasticity, and the spinnability of the spinning solution is lower than that of the other methods. It has many advantages compared to other methods, such as the ability to produce continuous fibers. According to subsequent studies by the present inventors, it was found that the spinnability of the spinning solution largely depends on the type of organic group in the side chain of the polymetalloquine. That is, organic residues with a large number of carbon atoms, such as higher acyloxy groups and higher alkoxy groups, are effective in improving spinnability, and the obtained precursor fibers are flexible and easy to handle, and organic residues with a large number of carbon atoms The spinnability and the strength and elastic modulus of the fibers are improved compared to the case where no organic residues are introduced or low organic residues are introduced. However, when a large amount of organic residues with a large number of carbon atoms are introduced into the side chain, the proportion of metal atoms in the precursor fiber decreases, resulting in a decrease in the density of the fiber after firing.
As a result, the strength and elastic modulus of the inorganic fiber deteriorates, and when organic residues with a large number of carbon atoms are present during firing, their combustion and thermal decomposition generate a wide variety of gases, causing local damage. Because there are differences in the atmosphere and therefore differences in the degree of combustion, when firing in large quantities, there is a disadvantage that the strength and elastic modulus of the inorganic fibers deteriorate, and the quality of the inorganic fibers becomes uneven. It's not enough. As a result of intensive research into these points, the present inventors have found that polymetalloxane containing polymetalloxane with phenoxy groups introduced into the side chain has significantly superior traction properties compared to the number of carbon atoms it contains. The present inventors discovered that fibers having excellent tensile strength and elastic modulus can be produced by imparting yarn properties and by firing a fiber precursor made from the polymetalloxane, leading to the completion of the method of the present invention. That is, the present invention [A] General formula

[expression] and/or

[Formula] (where M is a trivalent or tetravalent metal atom, Y is an organic residue, nitro group or halogen, m is 0
~5 integer, X ₁ is

Indicates an organic residue, hydrogen atom, nitro group, or halogen that is the same as or different from [Formula]. ) Structural units represented by 0.1 to 95 mol% and [B] General formula

[expression] and/or

[Formula] (where M is the same as above, X ₂ and X ₃ are

Indicates organic residues excluding [Formula]. ) To provide a method for producing inorganic fibers, which comprises spinning an organic solvent solution containing a polymetalloxane containing 99.9 to 5 mol% of structural units represented by the formula to form precursor fibers, and then firing the precursor fibers. be. The method of the present invention will be explained in more detail below. The raw material polymetalloxane used in the method of the present invention has the general formula [A]

[expression] and/or

Contains 0.1 to 95 mol% of the structural unit represented by [Formula] (wherein M, Y, m and

[expression] and/or

[Formula] (wherein M, X ₂ and X ₃ are the same as above). In the above general formula, M may be any metal that can be converted into a metal oxide by firing, but generally it is a metal atom that can be trivalent or tetravalent, specifically boron,
aluminum, gallium, indium, silicon,
Examples include germanium, tin, lead, yttrium, titanium, zirconium, rare earth elements, chromium, manganese, iron, cobalt, nickel, etc., and aluminum, silicon, titanium, zirconium, etc. are particularly useful. Y represents an organic residue, nitro group or halogen,
Specifically, alkyl groups such as methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, methoxy group, ethoxy group,
Alkoxy groups such as n-propoxy group, iso-propoxy group, n-butoxy group, iso-butoxy group,
Acyl groups such as acetyl group, propionyl group, benzoyl group, alkoxycarbonyl group such as methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, alkenyl group such as phenoxycarbonyl group, cyano group, vinyl group, propenyl group, phenyl or substituted phenyl groups, phenoxy groups, halogens such as chlorine and fluorine, and the like. When Y is substituted with a plurality of substituents, Y may be the same or different substituents, and m is an integer of 0 to 5, preferably an integer of 1 to 3. X ₁ is

[Formula] represents an organic residue, nitro group, halogen or hydrogen atom, which is the same as or different from [Formula], specifically Y or m as described above.
of

[Formula] group, alkyl group such as methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group , an alkoxy group such as n-butoxy group and iso-butoxy group, an acyl group such as an acetyl group, a propionyl group, and a benzoyl group, a halogen such as chlorine and fluorine, a nitrile group, and a hydrogen atom. X ₂ and X ₃ are

Indicates organic residues excluding [Formula], specifically methyl group, ethyl group, n
- Alkyl groups such as propyl group, iso-propyl group, n-butyl group, iso-butyl group, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, iso-butoxy group, etc. alkoxy group, acetyl group, propionyl group,
Examples include acyl groups such as benzoyl group. The polymetalloxane used in the present invention can be prepared by the method described below. For example, dimethylphenoxyaluminum, diethylphenoxyaluminum, dipropylphenoxyaluminum, dimethoxyphenoxyaluminum, diethoxyphenoxyaluminum, dipropoxyphenoxyaluminum, dimethylacetylphenoxyaluminum, dimethyldiphenoxyaluminum titanium, diethyldiphenoxytitanium, di-
(methylphenoxy)-diethyl titanium, di-
(cyanophenoxy)-dimethyltitanium, dimethyldiphenoxysilicon, di-(ethoxyphenoxy)-diethylsilicon, p-chlorophenoxy-trimethoxysilicon, p-nitrophenoxy-triethoxysilicon, p-ethylphenoxy-triiso-propoxyzirconium , diethyldiphenoxyzirconium, di-(ethoxycarbonylphenoxy)-dimethoxyzirconium, diethylphenoxyindium, p-methoxycarbonylphenoxy-diethoxyindium, o-cyanophenoxy-diiso-propoxyindium, dimethyldif Partial hydrolysis of organometallic compounds having phenoxy groups such as enoxytin, o-ethoxycarbonylphenoxy-triiso-propoxytin, or trimethylaluminum, triethylaluminum, tripropylaluminum, triethoxyaluminum, etc. Triiso-propoxyaluminum, diethylaluminium hydride, diiso-propoxymonoethylaluminum, monoethoxydiethylaluminum, tetraethyltitanium, tetrapropyltitanium, tetrabutyltitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, triethyltitanium Hydride, diethyl diiso-propoxy titanium, tetraethyl zirconium, tetraiso-propoxy zirconium, tetrabutyl zirconium, trimethyl zirconium hydride, diethyl diiso-propoxy zirconium, tetraethyl silicon, tetrapropyl silicon, methyl silicate, ethyl silicate, iso-propyl silicate, trimethyl Indium, triethyl indium, triethoxy indium, diethyl iso-propoxy indium, tetramethyl tin, tetraethyl tin, tetrapropyl tin, tetramethoxy tin,
Organic residues of polymetalloxane obtained by partial hydrolysis of tetraethoxytin, tetraisopropoxytin, etc.

[Formula] group, or by partially hydrolyzing a mixture of an organometallic compound having a phenoxy group and an organometallic compound not having a phenoxy group, or by partially hydrolyzing an organometallic compound having a phenoxy group. It can be produced by a method such as mixing a partial hydrolyzate of an organometallic compound that does not have a phenoxy group. Partial hydrolysis can be carried out under known conditions. Organic residues of polymetalloxane

[Formula] As a method for substitution with a group, mixing phenols with polymetalloxane obtained by partial hydrolysis of an organometallic compound at a temperature of usually 0 to 100°C causes an exchange reaction of side chain groups, which facilitates substitution. can do. In carrying out the present invention, the compounds used to introduce the above-mentioned substituted phenoxy groups include cresol, ethylphenol, propylphenol, butylphenol, dimethylphenol, methylethylphenol, diethylphenol, and methylpropylphenol. , ethylpropylphenol, dipropylphenol, trimethylphenol, triethylphenol, methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol, dimethoxyphenol, methoxyethoxyphenol, diethoxyphenol, methoxypropoxyphenol, dipropoxyphenol, trimethoxyphenol, Triethoxyphenol, hydroxyacetophenone, propionylphenol, butyrylphenol, diacetylphenol, acetylpropionylphenol, dipropionylphenol, triacetylphenol, methyl hydroxybenzoate, ethyl hydroxybenzoate, propyl hydroxybenzoate, butyl hydroxybenzoate , di-(methoxycarbonyl)-phenol, di-(ethoxycarbonyl)-phenol, di-(propoxycarbonyl)-phenol, tri-(methoxycarbonyl)-phenol, tri-(ethoxycarbonyl)-phenol, cyanophenol,
Chlorphenol, chlorophenol, nitrophenol, dinitrophenol, picric acid, etc. are suitable. In carrying out the method of the present invention, any organic solvent that can dissolve the polymetalloxane can be used, specifically ethyl ether, tetrahydrofuran, dioxane, benzene, toluene,
Examples include xylene and hexane. In carrying out the method of the present invention, [A] general formula in the raw material polymetalloxane

[Formula] and/ma Taha

The proportion of the structural unit represented by the formula (hereinafter referred to as the amount of substitution) is generally 0.1 to 95 mol%, preferably 1 to 80 mol%, most preferably 3 to 20 mol%, based on the metal atoms in the total polymetalloxane. It is mole%. If the amount of substitution in the polymetalloxane is less than 0.1 mol %, the effect of improving spinnability and physical properties will be slight, while if it exceeds 95 mol %, the stringiness will become poor, which is not preferable. The effect on stringiness is quite remarkable when the amount of substitution is 1 mol% or more compared to the unsubstituted product, and the stringiness improves in proportion to the amount added, but when the amount of substitution is 3 mol% or more, The degree of improvement in spinnability becomes less noticeable. The degree of improvement in stringability also depends on the type of coexisting side chain substituents. Generally, those substituted in a range of 1 to 80 mol% exhibit the most stable and high stringiness, and when the amount exceeds 80 mol%, this effect gradually decreases until 95 mol%.
If it exceeds this, the solubility of polymetalloxane in organic solvents decreases, so the stringability and formability become equal to or lower than those without additives, and solid content precipitates when concentrated to obtain a viscous liquid. Because of this, the replacement effect disappears. Therefore, by using a polymetalloxane having a phenoxy group in the side chain specified in the method of the present invention as a spinning solution, the spinnability is improved and fibers with extremely high tensile strength and elastic modulus when spun and fired are obtained. The effect that molded bodies can be manufactured is exhibited. Although it is not clear why the above-mentioned effects are produced by having a phenoxy group in the side chain of polymetalloxane, the inclusion of the phenoxy group in the side chain causes polymetalloxane to have lubricity.
As a result, spinnability and formability are improved, and normally, when an organic residue with a carbon number similar to that of a phenoxy group is introduced into the side chain, the side chain group burns within the precursor fiber, causing local heating, which occurs during firing. This is undesirable because it causes local differences in the degree of firing of the fibers, which reduces the homogeneity and density of the fibers, which in turn causes a decrease in the strength and elastic modulus of the fibers. However, in the case of phenoxy groups, the firing temperature It is considered that local heating is avoided because a considerable amount of phenoxy groups are decomposed and eliminated by the time the firing process is reached, resulting in the effect that the fiber strength and elastic modulus do not decrease due to firing. It is sufficient that the degree of polymerization of the polymetalloxane used in the method of the present invention is 2 or more, and there is no particular upper limit, but the degree of polymerization is generally
1000 or less are used. Polymetalloxane is soluble in organic solvents such as ethyl ether, tetrahydrofuran, benzene, toluene, and hexane, and at an appropriate concentration becomes a viscous liquid with excellent stringiness. The relationship between the concentration of polymetalloxane and the stringiness of its solution varies depending on the type of polymetalloxane used, its degree of polymerization, and the solvent, and cannot be unambiguously determined, but generally the viscosity at room temperature is 1 poise or more. Solutions below 5000 poise are suitable for spinning. The spinning solution is therefore prepared to provide a viscosity within this range. It is desirable to add organic polymers such as polyethylene glycol, polyvinyl formal, polyvinyl acetate, and other suitable organic substances to the spinning solution in order to improve spinnability. Additionally, a small amount of one or more compounds containing lithium, beryllium, boron, sodium, magnesium, silicon, phosphorus, potassium, calcium, titanium, chromium, manganese, yttrium, zirconium, lanthanum, tungsten, etc. is added to the spinning solution. This is desirable in order to improve various physical properties of the obtained inorganic fiber. In addition, by mixing two or more types of polymetalloxanes made of different metal atoms, spinning and firing, composite oxides [e.g. spinel type oxides (MgAl ₂ O ₄ , Al-Si spinel, etc.), perovskite type oxides] It is also possible to produce fibers with excellent properties such as materials (LaAlO ₃ , etc.). According to the method of the present invention, a polymetalloxane having a phenoxy group is used as a raw material, a silicon-containing compound is mixed therein, and a precursor fiber with a high silica-alumina content obtained by spinning the mixture is fired. As a result, short, long, or continuous silica-alumina fibers having extremely high mechanical strength and heat resistance can be produced. Among these polymetalloxanes containing phenoxy groups, in the present invention, the alumina content is 10%.
Above, preferably 20% or more is used.
The alumina content referred to here is given by [51/(molecular weight of structural unit)] x 100 (%). When the alumina content is less than 10%, it is difficult to obtain silica-alumina fibers with practical strength. On the other hand, as a compound containing silicon to be mixed with

Polyorganosilol having the structural unit of [formula] Kisan,

A polysilicate ester having the structural unit of [Formula] (R ₁ and R ₂ are organic atomic groups) is suitable, but an organosilane having the structure R _o SiX _4-o (X is OH, OR, etc.) is suitable. (R is an organic atomic group, n is an integer of 4 or less), a silicate ester having a structure of Si(OR) ₄ (R is an organic atomic group), and other silicon-containing compounds in general can be used. It is desirable that the silicon-containing compound to be mixed has a high silica content, but one with a low silica content may also be used. In particular, when producing silica-alumina fibers with a low silica content, the silica content of the silicon-containing compound to be mixed may be small. Further, it is desirable that the silicon-containing compound to be mixed is uniformly dissolved and mixed in the polyaluminoxane solution, but it may be dispersed and mixed without being dissolved. It is preferable that the silicon-containing compound to be mixed is itself dissolved in the polyaluminoxane solution and has stringiness, but this is not an essential condition. The maximum amount of silicon-containing compounds that can be mixed is:
Although it depends on the spinnability of the silicon-containing compound itself, even silicon-containing compounds that do not have very good spinnability can have a silica content of 60% by weight in the silica-alumina fibers after firing. Even if the amounts are mixed, the mixed polyaluminoxane solution maintains sufficient spinnability to be able to be spun. In some cases, it may be effective to mix two or more silicon-containing compounds into the polyaluminoxane solution. For manufacturing silica alumina fibers
The ratio of SiO ₂ :Al ₂ O ₃ is desirably adjusted to 1-30% by weight: 99-70% by weight. To perform spinning from a polymetalloxane solution,
So-called dry spinning is convenient, but centrifugal spinning,
Other suitable spinning methods may be followed, such as blow spinning. Spinning is carried out at room temperature, but the spinning solution can be heated if necessary. It is also desirable to appropriately adjust the atmosphere around the spun fibers to obtain good results. Dry removal of the solvent contained in the fibers is not particularly necessary when the fibers are thin, but it can be carried out during or after spinning. Precursor fibers produced according to the invention typically have an average diameter of 1 to 100 μm. However, it is not limited to this range. In carrying out the method of the present invention, the precursor fibers spun as described above are then subjected to steam treatment, if necessary.
After pretreatment with hot water treatment, acid treatment, or a combination of these, firing is performed. The inorganic fiber precursor obtained in this way is formed into a fibrous form with a high concentration of fiber forming substances and a uniform continuous state, so it is extremely convenient for improving the various physical properties of the inorganic fiber after firing. It is. In addition, the inorganic fiber precursor obtained by the method of the present invention is itself a strong and transparent fiber, and by processing it into a form such as a fabric and then firing it, an inorganic fiber having that form can be produced. You can also get products. The inorganic fiber precursor in the method of the present invention is infusible with respect to heat, and if it is fired as it is in an oxygen-containing atmosphere such as air, it can be easily made into an inorganic fiber without changing the fiber shape. In other words, for example, in the context of manufacturing alumina fibers, if the precursor fibers are fired in an oxygen-containing atmosphere, such as air, they will substantially change to alumina fibers at about 700°C, and at about 900°C. In the above manner, transparent and strong alumina fibers can be obtained. Furthermore, in order to obtain these various alumina fibers, the precursor fibers may be fired in an inert atmosphere such as nitrogen or in vacuum, and then exposed to an oxygen-containing atmosphere to remove organic or carbonaceous materials.
Further, the obtained alumina fiber may be further fired in a reducing atmosphere such as hydrogen. It is also desirable to maintain tension on the precursor fibers or alumina fibers during these firing steps in order to produce strong alumina fibers. The firing temperature varies depending on the constituent elements of the inorganic fiber to be manufactured and the use of the inorganic fiber, and when fibers with high strength and high modulus are required, such as in fiber reinforced composite materials, the firing temperature is 900 to 1800℃,
900-1500℃ for silica-alumina fibers, 800-1500℃ for titania fibers, and 800-1500℃ for zirconia fibers.
A temperature range of 1000℃ to 2500℃ is used, and fibers with a large specific surface area are generally advantageous when applied to catalysts (or catalyst carriers), and depending on the chemical reaction conditions to which the catalyst is applied, fibers such as alumina, silica alumina, titania fibers, etc. In this case, a temperature of 400℃ to 1500℃ is adopted. Furthermore, for example, in the case of fibers that utilize the ionic conductivity of zirconia, it is preferable to fire them above the well-known transition point of about 1000 to 1100°C, and firing conditions vary depending on the fiber's use and constituent oxides. I understand something. According to the method of the present invention described in detail above, when producing metal oxide fibers from polymetalloxane, the spinnability is significantly improved, and the tensile strength and elastic modulus of the metal oxide fibers are significantly improved. It is effective. Embodiments of the present invention will be described below with reference to Examples, but the present invention is not limited to the following Examples. Example 1 Monoiso-propoxy diethyl aluminum 1
mol was dissolved in 600 c.c. of ethyl ether and hydrolyzed with 1 mol of water to obtain polyiso-propoxyaluminoxane with a degree of polymerization of 130. Next, 0.1 mole of ethyl O-hydroxybenzoate is added and stirred under reflux to dissolve 0.1 mole of iso-propoxy groups in the polyiso-propoxyaluminoxane.

Substituted with [Formula] group. Dissolve this polyaluminoxane in benzene,
After distilling off the ether, the structural formula is 0.07 mol of ethyl silicate given by was dissolved. This was concentrated so that the polyaluminoxane concentration was 55% by weight, and the viscosity was 300 poise, and it was transparent and homogeneous with no uneven viscosity.
After degassing this as a spinning stock solution, the number of pores is 96 and the pore diameter is 50 μm.
With the spinneret, 50m
Extrusion spinning was performed at a speed of min. The obtained precursor fiber is transparent and its diameter is 15
It was μm. After leaving the precursor fiber in an atmosphere with a temperature of 80°C and a relative humidity of 100% for 15 minutes, the temperature increase rate was 300%.
C/hr in a tube furnace to 1200°C in air, colorless and transparent silica-alumina fibers with a silica content of 20% were obtained. When we measured the diameter, tensile strength, and elastic modulus of these 20 fibers, the average diameter was 9.0 μm, and the tensile strength was
The elasticity was 25t/cm ² and the elastic modulus was 2000t/cm ² . The variation in diameter was extremely small within 0.2 μm. Note that the strength is a value measured at a gauge length of 20 mm, and the same applies to the following examples. Examples 2 to 10, Comparative Examples 1 and 2 Monoiso-propoxy diethyl aluminum 1
mol was dissolved in 600 c.c. of ethyl ether and hydrolyzed with 1 mol of water to obtain polyiso-propoxyaluminoxane with a degree of polymerization of 130. The amount of p-hydroxyacetophenone shown in Table 1 was added to the polyiso-propoxyaluminoxane, and the mixture was stirred under reflux to dissolve the polyiso-propoxyaluminoxane.
Each of the iso-propoxy groups

Substituted with [Formula] group. Almost 100% of the isopropoxy groups were substituted with acetophenoxy groups. 0.07 mol of the same ethyl silicate as used in Example 1 was added to each and concentrated. After degassing the concentrate, the number of pores is 96 and the pore diameter is 50μ.
It was extruded from a 6 m spinneret into a 6 m long spinning tube and dry spun. The obtained fiber precursor was fired in the same manner as in Example 1 to obtain colorless and transparent silica-alumina fibers with a silica content of 20% by weight. The physical properties of this silica alumina fiber were measured and shown in Table 1.

【table】

[Table] From the above results, it is clear that silica alumina fibers with good spinnability, excellent tensile strength and elastic modulus can be produced when the proportion of phenoxy groups is within the range of 0.1 mol % to 95 mol %. Comparative Example 3 In the synthesis of polyaluminoxane of Example 1, O
A spinning stock solution was obtained in the same manner as in Example 1 except that 0.1 mol of caproic acid was added in place of ethyl hydroxybenzoate. This was spun in the same manner as in Example 1, but the spinnability was poor and the diameter of the obtained precursor fiber was 28 μm.
It was m. This precursor fiber was brittle and difficult to handle. When this was fired in the same manner as in Example 1, the diameter of the obtained fiber was 17 μm and the fiber strength was
It was 13t/ ^cm2 . Example 11 0.2 mole of O-methylphenoxy-diethyl-aluminum and 0.8 mole of triiso-propoxyaluminum
mol was dissolved in 600 c.c. of dioxane and hydrolyzed with 1 mol of water to obtain polyaluminoxane with a degree of polymerization of 80. This polyaluminoxane has 80 mol% of iso-propoxy groups based on Al atoms as organic residues in the side chains.
It contained 20 mol% of O-methylphenoxy groups.
In this dioxane solution of polyaluminoxane, 0.035 mol of the same ethyl silicate as used in Example 1 was dissolved and concentrated so that the concentration of polyaluminoxane was 70% by weight. After degassing the concentrate, the number of pores
The material was extruded from a 64 spinneret into a 6 m long spinning tube and spun. The diameter of the obtained precursor fiber was 15 μm. When this precursor was treated and fired in the same manner as in Example 1, colorless and transparent silica-alumina fibers with a silica content of 10% were obtained. This fiber had a diameter of 9.0 μm, an average strength of 23 t/cm ² , and an elastic modulus of 2300 t/cm ² . The variation in diameter was within 0.2 μm. Example 12 In a dioxane solution of polyaluminoxane with a degree of polymerization of 40, in which 80 mol% of the organic residues are iso-propoxy groups and 20 mol% are ethyl groups, p-cyanophenol was added corresponding to 30 mol% of the organic residues. Ethyl silicate was further mixed in such an amount that the silica content of the fibers after firing was 30%. Concentrate the mixture to obtain a liquid with a viscosity of 7500 cp and excellent stringiness,
This was dry spun to obtain a precursor fiber with a diameter of 16 μm. The obtained precursor fiber was heated at a temperature of 80℃ and a relative humidity of 100℃.
% atmosphere for 30 minutes and then calcined at 1200°C to obtain high-strength silica-alumina fibers with a diameter of 10 μm and a strength of 23 t/cm ² . Comparative Example 4 For comparison, silica alumina fibers were produced in the same manner as in Example 12, except that p-cyanophenol was not mixed. As a result, silica-alumina fibers with a fiber diameter of 18 μm, a strength of 12 t/cm ² and an elastic modulus of 1300 t/cm ² were obtained. Example 13 1 mol of triethylaluminum is dissolved in 600 c.c. of tetrahydrofuran, 1 mol of water and 0.1 mol of m
-Cresol was simultaneously added dropwise to obtain polyaluminoxane with a degree of polymerization of about 40. Concentrate the polymer and reduce the viscosity
When dry spinning was performed using a 7500 cp viscous spinning solution, a precursor fiber with excellent spinnability and a diameter of approximately 16 μm was obtained. When the fiber precursor was left in an atmosphere of 70°C and 80% relative humidity for about 30 minutes and then fired to 1200°C, the fiber diameter was 10.
Alumina fibers having a tensile strength of 18 t/cm ² and an elastic modulus of 1700 t/cm ² were obtained. Example 14 90 mol% of the organic residues are iso-propoxy groups and 10 mol% are

[Formula] Concentrate a benzene solution of polytitanoxane with a degree of polymerization of 30 to obtain a liquid with a viscosity of 7500 cp and excellent stringiness.
This was dry spun to obtain a precursor fiber with a diameter of 20 μm. The obtained precursor fiber was heated at a temperature of 80℃ and a relative humidity of 100℃.
% atmosphere for 30 minutes and then fired at 1200°C to obtain high-strength titania fibers with a diameter of 12 μm and a tensile strength of 12 t/cm ² . Comparative Example 5 A benzene solution of polytitanoxane with a degree of polymerization of 30, in which the organic residue consists only of iso-propoxy groups, was concentrated to obtain a spinnable liquid with a viscosity of 7500 cp, which was dry spun to form a precursor with a diameter of 25 μm. Obtained fiber. The obtained precursor fiber was heated at a temperature of 80℃ and a relative humidity of 100℃.
% atmosphere for 30 minutes and then fired at 1200°C to obtain titania fibers with a diameter of 15 μm and a strength of 6 t/cm ² . Example 15 1 mol of tetraethoxyzirconium and triiso
- 0.05 mol of propoxyyttrium was dissolved in 600 c.c. of tetrahydrofuran, hydrolyzed with 1 mol of water, 0.2 mol of methyl salicylate was added and stirred, and then concentrated to a viscosity of 7000 c.c. to obtain a spinning stock solution. The spinning dope was dry-spun to obtain a precursor fiber with a diameter of 30 μm. When this was fired in air to 1300°C at a heating rate of 300°C/hr, zirconia fibers with a fiber diameter of 18 μm, a tensile strength of 10 t/cm ² and an elastic modulus of 1500 t/cm ² were obtained.

Claims (1)

[Scope of Claims] 1 [A] General formula [Formula] and/or [Formula] (where M is a trivalent or tetravalent metal atom, Y is an organic residue, nitro group or halogen, m is 0
An integer of ~5, X ₁ represents an organic residue, a hydrogen atom, a nitro group, or a halogen, which is the same as or different from [Formula]. ) 0.1 to 95 mol% of structural units represented by [B] General formula [Formula] and/or [Formula] (where M is the same as above, and X _{2 and} A method for producing an inorganic fiber, which comprises spinning an organic solvent solution containing a polymetalloxane containing 99.9 to 5 mol% of the structural unit represented by the following formula to form a precursor fiber, and then firing the precursor fiber. 2 M in the general formula is aluminum, indium,
Claim 1, characterized in that a polymetalloxane that is one or more of silicon, tin, titanium, or zirconium is used.
A method for producing an inorganic fiber as described in Section 1. 3. The method for producing inorganic fibers according to claim 1 or 2, wherein m in the general formula is an integer of 1 to 3. 4 [A] General formula [Formula] and/or [Formula] (where M is aluminum, indium, silicon, tin, titanium or zirconium, Y
is an organic residue, nitro group or halogen,
m is an integer of 1 to ₂ ; 4. The method for producing inorganic fibers according to claim 1, 2 or 3, characterized in that a polymetalloxane having 1 to 80 mol% of the structural unit represented by the following formula is used.