DE1918754A1 - Process for the production of inorganic fibers - Google Patents

Description

FARBENFABRIKEN BAYER AG

LEVERKU SEN-B * yerwerk GB / Schr patent department

April 11, 1969

Process for the production of inorganic fibers

The invention relates to a method for the production of inorganic Pasern.

There are a number of methods for making inorganic fibers known; one of the oldest is the manufacture of glass threads by spinning a glass melt. The one with it The temperatures to be used place high demands on the equipment. It was therefore endeavored to stop the spinning process an aqueous solution using conventional methods of the synthetic fiber industry.

The prerequisite for the spinning process from an aqueous system is the spinnability of the respective solution. This is expressed by the fact that when a glass rod is immersed and withdrawn from such a solution, the liquid is drawn along as a more or less long thread and does not drip off, as is normally the case. It is known from the literature that spinnability can occur in solutions if these contain elongated, lyophilic colloid particles with free rotation and mobility, between which there are interaction forces (Kolloid-Zeitschrift122, / ~ 1952_7 pp. 25-39). This phenomenon cannot be explained by the viscosity alone. So is z. B. a viscous silica sol not spinnable because it contains spherical colloid particles. Glycerin with a viscosity>? _rel = 3 * 7 is not spinnable, however

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Chicken protein that has the same viscosity (Kolloid-Zeitschrift 61 / ~ 1932_7 pp. 250 - 256). A V ₂ O ₅ sol is, although it contains elongated rod-shaped colloid particles, not spinnable because these rods are too rigid (Kolloid-Zeitschrift 1_2 °; / "1952_7 pp. 25-39). The majority of inorganic sols are not spinnable , because the conditions mentioned are not met. Spinnability is therefore a very special state of colloidal solutions, which must first be achieved by setting special factors before a spinning process can take place.

US Pat. No. 2,969,272 describes the production of silicate materials by a spinning process from aqueous solution. The spinnability is achieved by .that · mixtures of silica sol and alkali silicate by adding polymerizing substances such as B. Bp (X ,, AlpO ^ ₅ or ZnO are polymerized at elevated temperature by dehydration to linear polymeric silicate fibrils with a molecular weight over 5OCO, whereby a spinnable sol is formed. * ·

In the German Auslegeschrift T.249.832 a. Process for the production of inorganic threads described in which metal salt solutions of an aliphatic carboxylic acid are mixed with an '"excess of this acid, concentrated and" polymerized by a heat treatment in the atmosphere of this carboxylic acid to form a viscous, spinnable solution, chain-like polymers with 1000 to 100Ö0 molecules 'arise per chain. The atmosphere of the carboxylic acid and ^"v Säureüber-- shot are needed 'to avoid soluble phase. The applicable Säureüber- ^x shots in relation to the dissolved oxide are, depending on * the deposition of a second, uri ~''''' Oxide between 2: 1 and 8: 1.

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1918 7 h A

In U.S. Patent J>. 3 2.865 describes a process in which aqueous, inorganic metal salt solutions are concentrated to a viscosity of 1 to 1000 pois, the solids content being up to 50 % , which are then spun and burned to form an oxide. The salts mentioned are the sulfates, chlorides, oxide chlorides, phosphates and nitrates of Al, Be, Cr, Mg, Th, U and Zr.

In this context, the British patent specification I.030..P3? process described, in which Zr salt solutions such as acetates, lactates or oxide chlorides are converted into a spinnable sol ^{by concentrating to 40 to 48 c} , i> oxide. In order to obtain good fibers, the brine must be spun immediately. "

Salt solutions can normally only be concentrated until the solubility product is reached. 'Further concentration is possible, but supersaturated, unstable solutions are then produced. For example, a solution of MgSOj saturated at 20 ° C contains ₁ . 7H _? 0 35.6 g HgSO ^ in 100 g H _p 0 (solution 8.3 ig of MgO) and an Al ₀ (SO ^) ,. 18H ₂ 'O solution 56.3 g of Al ₀ (SO ₁₁ ) - = 7.9 ¹ % of Al ₀ O ,. From the literature references discussed above, however, it emerges that in order to achieve the necessary viscosity, concentrations of 5 to 38 % of oxide have to be set. This can be achieved, as is known, that of hydrolyzable salts, such as. B. acetates or chlorides, which are converted into a sol during concentration or to which alkaline substances such as metal hydroxides or oxides (CaO or MgO) or directly metals (Al or Mg) are added. The methods used are those which are customary for the production of inorganic sols, which, after further treatment, in special cases, are necessary for a spinning

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BATH ORIGINAL

have process necessary property of spinnability. the end Until now, pure aqueous salt solutions could not be used without the above special measures no spinnable solutions are obtained.

To produce spinnable inorganic solutions are $ e specific to the type of solution, some quite expensive measures, such as polycondensation or polymerization processes necessary at elevated temperature, partly in a protective atmosphere.

The object of the present invention is the production inorganic fibers made of spinnable, predominantly or pure Simplify inorganic solutions by adding solutions it is assumed that they can be produced from readily available commercially available substances, if possible at room temperature, without laborious measures, and that also without a carboxylic acid atmosphere or excess can be kept for a longer period of time without separating out insoluble constituents. The solution should be characterized by good spinnability. The spun threads should withstand high shaft distortion and be convertible into inorganic threads by annealing.

The invention therefore relates to a process for the production of inorganic fibers in which threads are drawn from a spinnable solution and then stabilized by a thermal aftertreatment, characterized in that a solution of a metal compound AX ^ is first produced (A = Si, Ge, Ti , Sn, V, U, Th, Zr, Hf; X = halide, acetate, nitrate, sulfate, hydroxide, alkoxide), the solution then _{mixed with 0.05 to 1 mol of a compound of the type B m} Y (B = · H, Al, Ca, Ba, Sr, Mg, Be, rare earths, Cr, Mn, Fe, Ni, Co, Cu, Zn, Sb, Bi; Y = acid residue; = valence of the acid residuei where the concentration of the mixture obtained is so is set that

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the concentration of A, calculated as oxide, 20 to 61 percent by weight is, the mixture is spun at temperatures of 15 to 70 ° C and the resulting Paser then by annealing is stabilized.

The preferred compounds of the AXk type are the halides of the metals mentioned, with particularly good results their chlorides.

The acid residue in the compound of type B ^ Y that is responsible for evoking added to the spinnability in a concentration of 0.05 to 1 mol, preferably 0.15 to 0.5 mol, per mol of metal A. can be inorganic or organic in nature. When using the pure acids (B = H), v / earths per metal A are preferred 0.05 to 0.5 moles of acid are used. Both monobasic and polybasic acids can be used. As inorganic Acids are particularly suitable sulfuric acid, phosphorous acid and sulfamic acid. Carboxylic acids are suitable as organic acids, substituted carboxylic acids, polycarboxylic acids, oxy- and keto-carboxylic acids, sulfonic acids, amino acids and aminosulfonic acids. The organic acids should be soluble in concentrated hydrochloric acid and have a pk value of less than 3.4. The following organic acids can be used with good results: benzenesulfonic acid, o-phenolsulfonic acid, Ligninsulfonic acid, sulfosalicylic acid, taurine, glycocolla, citric acid, malic acid, tartaric acid, malonic acid, oxalic acid, Pyruvic acid, lactic acid and chloroacetic acid.

It is not necessary to use the pure acids. In fact, it is often more beneficial to take their salts, especially those that leave a glow-resistant residue. In this way, a wide variety of thread compositions can be created achieve. So you can z. B. for the production of a thread, which in addition to the resulting from the AX ^, - solution dioxide

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AO _{2 should} still ^{contain A} l ₂ ° 3, from an AX ^ solution, such as. B. TiCl ^ in water, to which aluminum sulfosalicylate is then added. From the resulting spinnable solution, after spinning and annealing, a thread is created that consists of AIpCU and TiOp. If a thread of the composition CaTiO., Is created, the aqueous TiCl ₁ , solution z. B. Ca tartrate in a molar ratio. 1: 1 added and in this way a thread is obtained which, in addition to TiOp, also contains CaO.

Further constituents can be added to the spinning solutions without the spinnability being significantly impaired. Such additives come, for. B. inorganic "brine in question. To a solution of TiCl ^ in water, which has been made spinnable by adding calcium tartrate, SiOp sol can be added aO) _x . (TiO ₂ ). ^ iO ₂ ) _{z become} possible.

In detail one goes in the preparation of the spinning solutions z. B. from the metal chlorides so that they are mixed with a necessary amount of solvents for dissolution, usually V / water, or the metal chlorides are added to the solvent, with partial solvolysis taking place and viscous, clear, transparent solutions or brines are formed. In this state, the solutions have a high viscosity, but no spinnability. However, a drastic change in spinnability occurs when Qr.05 to 1 mol (per mol of metal) of a suitable acid is added. So z. B. the addition of 0.15 mol H ₂ SO ^ to a viscous TiCl ^ solution that a thread of several meters in length up to a diameter of a few / um can be pulled out when a glass rod is immersed.

Solutions for the purposes of the present invention are not only true solutions of the compound AX ₂ or mixtures thereof with

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Compounds of type B_Y understood, but also mixtures that are in the sol state .beinden. In each case, however, the phases are homogeneous and liquid at ambient temperature. The preferred solvent used is water; however, other solvents are also suitable, such as. B. alcohols or mixtures of different solvents. Preferably, the solvent should be used in an amount of k to 10 moles per mole of metal compound AXj. to be available.

The particles occurring in the spinning solutions represent solvolysis products and can be described by the general formula ^AO p " _a ^x p _a · ^H _m ^Y (BY) .nL. It means:

A * Si, Ge, Ti, Sn, V, U, Th, Zr, Hf X = halide, acetate, nitrate, sulfate, hydroxide, alkoxide L = solvent molecules (HpO, alcohols etc.) HY = added acids or their salts B _m Y a = 0.25 to 1.5

q = 0.05 to 1

η = varying number of solvent molecules (L) with

a value of at least = 1
m = valence of the acid residue.

These particles are polymeric and are responsible for the occurrence of spinnability. They do not have to be produced by polymerisation processes, but are formed by simply mixing together the components AX ^, H ^ O and H _m Y or B _m Y. This makes the production of spinning solutions extremely easy. While q is fixed by the amount of acid or salt added, a can vary between 0.25 and 1.5. The value depends on the concentration of the spinning solution, the type of acid added and its amount, and the metal atom A.

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BATHROOM 0RI6MAL

So one gets ζ. B. when dropping TiCIh in .Wasser and adding 0.15 mol of H SOj, a spinning solution that _{has good spinnability with a TiO p} content between 33 and 42 % and in which the Ti: Cl ratio is 1: 0, 77 and thus a = 0.385. If 0.15 mol of sulfosalicylic acid is used instead of H ₂ SOj ₊ , the Ti: Cl ratio at a concentration of 38.1 % TiOp in the spinning solution is 1: 1.09 and thus a = 0.505. In the case of other metals, spinnability occurs at other oxide concentrations; here, other values of a- are also found. In the spinning solution, which is obtained from UCIh, water and 0.3 mol HpSOj ₊ and which contains a concentration of 58 * 5% UOp in the range of very good spinnability, one finds a UrCl ratio 'of 1: 2.77 (a = 1.3§), in the _{spinning solution prepared from ThCIjTj -} , water and 0.3 mol H ₂ SOj ₊ a Th: Cl ratio of 1: 2.93 (a = 1, '47) with an oxide content of 51 .7 %

When implementing other output connections, such as. B. Ti (n) (OCj ₊ H ₉ ) J ₊ with 1 mol H _p 0 and 0.5 mol H ₂ SOj ₊ one obtains similar ratios. The spinning solution, from which the excess butanol produced by the hydrolysis was distilled off, contains 3.4 % TiO ₂ with a Ti: C _{J +} H _Q OH ratio of 1: 3.12 (a = 1.56). · ■

When using hydroxides as starting material, it is simply sufficient to add the relevant acid or the corresponding metal salt which contains the acid as an anion. The milky, jelly-like hydroxide gel of Ti (OH) J ₊ z. B., which has no spinnable properties, goes into a clear, sticky, spinnable syrup in a few hours at room temperature _{after the addition of TiOSO 1 ^ and any dissolving acid.}

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■ ORIGINAL BATHROOM

The hydroxides do not have to be used as such, they can advantageously also be prepared by hydrolysis of hydrolyzable salts. Such as nitrates, acetates, sulfates, oxychlorides, among others, by hydrolyzing the aqueous solutions of these salts in the heat and the acid is suctioned off until the Solution solidified to form a hydroxide gel. The metals must. are by no means already in the desired tetravalent state, this can only be formed by a redox reaction during production, so that, for example, higher-valued compounds such as V ₃ O ^, which is reduced by dissolving in HCl and alcohol, can also be used.

The acids or their salts can be added in one concentration from 0.05 to 1 mole per mole of AXh. Are there Small amounts of acid, such as 0.15 to 0.5 mol, are particularly advantageous, since this results in the highest oxide concentrations in the spinning solution let reach. These threads show good drying properties and form a dense structure. Spinning solutions with higher acid contents it is not possible to concentrate so highly, the threads are often hygroscopic and tend to form a porous structure. Acid mixtures or their salt mixtures can also be used in the specified concentrations to achieve the spinnability can be used.

The preparation of the spinning solutions can be done by adding the appropriate solution to the dilute solution of the starting material Amount of acid is added and the solvent is drawn off at temperatures from 15 to 60 ° C. until sufficient spinnability is reached. Temperatures from 20 to 40 ° C are preferred. But you can also choose the concentration of the starting substance so that the finished product after the addition of the acid

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BATH ORIGINAL

191 87-5A

AO

Spinning solution is present. It is still possible to use the AX ^ connection z. B. To add TiCK dropwise to a solution of the acid in water, until the concentration is reached at which the solution shows spinnable properties, or the acid, such as z. B. HpSOh first add to the TiCl ^ and this solution hydrolyze with the necessary amount of water. This shows the ease with which the spinnable hydrolysis products described form.

If the acids added are "volatile compounds", this process yields oxide threads or Threads that consist of oxide mixtures, if two or more metal compounds are used at the same time. Here you can the resulting threads consist of mixed crystals, such as. B. TiO (SnOp) or the oxides can be present next to one another. This allows threads with special properties to be produced. If the added acid is not volatile or changes in such an order, as is the case with the addition of H ^ PO-, which is converted into H ^ POu during the heat treatment, so form phosphate threads, which can also contain one or more metals, depending on whether one or more Metal compounds has run out. Here, too, the properties of the threads can be varied by processing mixed spinning solutions.

The spinnable solutions thus obtained during spinning, the elevated at room temperature or slightly temperature in a conventional manner can be carried out, the threads run continuously through a spinning shaft which may have in its lower part a temperature up to 5OO ⁰ C where it warped to a diameter of a few / µm (usually from 2 to 10 / µm) and afterwards

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BATH

AA

can be wound up. The flexibility and strength that the crystal-clear threads already have at this point in time, enable weaving or the production of felts or fiber mats. They can be stored for as long as you like in this state will. There is also the possibility of spinning the threads in a suitable felling bath and this afterwards Anneal coagulation. Also spinning in a centrifugal spinning machine is possible. Here the threads are flung out at the periphery of a rotating spinning vessel, pass through a dry zone and are then absorbed. This method is suitable e.g. for the production of staple fibers, which are then fed continuously or discontinuously to the temperature treatment.

However, the threads can also immediately after leaving the spinning shaft be passed through the high temperature zone. At the beginning there is a temperature of 100 to 400 ° C; the The final temperature largely depends on the sintering behavior and the Melting point of the resulting compound, it must be used for high-melting oxides such. B. ZrOp or ThO accordingly be higher than with lower melting compounds such. B. TiOp, SnOp and the like, where you can deal with temperatures from 800 to 1100 ° C. While in the spinning shaft already A large part of the solvent has been split off, the remaining organic and volatile inorganic constituents are here removed. Because of the special composition of the spinning liquids the volatile constituents are not released intermittently, but rather continuously, occurs uniform compression of the material. With a suitable choice of the sintering conditions, however, one has it in hand, at one time porous threads (as they are useful as catalyst carriers) to be created, at other times dense fibers for Manufacture reinforcement purposes.

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AX

By the method described, it is possible to produce an extremely large number of inorganic threads, including oxide threads, such as. B. TiO ₂ , SnO ₂ , ZrO ₃ , VO ₂ , UO ₂ , ThO ₂ , phosphate-containing oxide threads, such as. B. TiO _? .xP _? O ^, SnO _g .xP O ₁ -, ^Zr0 2 ' XP ₂ O, -, threads that consist of mixtures of the oxides mentioned and also those that additionally contain another oxide, such as. B. Ti0 ₂ / Si0 ₂ , TiOg / CaO, TiO _p / MgO, TiO ₂ Al ₂ O ₃ and threads that consist of more than two oxides, such as. B. TiOp / CaO / SiOp. The composition is not limited to the oxides mentioned. If, instead of the "acids mentioned, their Fe, Ni or Co or also Zn, La or Cer salts are added, threads that additionally contain these oxides are also accessible. If salt mixtures of acids that reduce the spinnability in the If the solutions described are used, threads can be produced which, in addition to the oxide AOp formed from the AXh solution, also contain a larger number of oxides of other metals.

A few examples will now be given showing the versatility of the process.

Example 1 TiOp threads

192 * 7 g of TiClji were added dropwise to a mixture of 115.6 g of water and 15.6 g of 95% sulfuric acid (Ti: HpSO ^ = 1: 0.15) with stirring. With initially vigorous evolution of HCl, a sticky spinnable liquid was formed which contained 40% TiOp and which, after it had been freed from gas bubbles by evacuation, was spun from a spinneret at room temperature. The spinning chimney had a temperature of 60 to 100 ° at the beginning and up to 200 ° C. at the end. It was charged with preheated air which flowed through it in the spinning direction. After leaving the spinning shaft

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1918764

the threads were crystal clear, flexible and strong. They were now pulled through a high-temperature zone, which initially had a temperature of 400 ° and initially a temperature of 1100 ° C. After the annealing process, the filaments had a diameter of 1 to 2 µm, were strong and flexible, and were wound onto a drum. They were dense and consisted of polycrystalline TiO ₂ in the rutile form.

Example 2 TiO ₂ threads

To 85 g of titanium tetrabutoxide Ti (OC ₂ , ^ K, 16.75% of a 73.1% sulfuric acid were added dropwise with cooling, which corresponds to a molar ratio of Ti: H ₃ O: H ₂ SO ^ of 1: 1: 0.5. Finally, 16.3 g of the butanol formed by the hydrolysis were distilled off at 20 ° C. under a pressure of 2 mm Hg, leaving a brown, spinnable solution with a TiO ^ content of 23.4 % The further treatment took place as indicated in Example 1.

Example 3 TiOg threads

TiOp threads could also be spun from the solution prepared as follows: 1 mol of freshly precipitated Ti (OH) ^ sludge was 64 g = 0.4 mol of TiOSO ₂ . mixed and HCl added until the slurry cleared in the heat. The solution was brought to a concentration of 36 % TiO _ where it showed good spinnability.

Example 4 g
1 mol = 189.7 g of TiCl ₂ were added dropwise to 200 g of ethanol. Then 29.4 g of H ₀ SO ₂ ^ (100%) (0.3 mol) were added and the excess ethanol was stripped off in vacuo until the solution contained 26.5 % TiO ₀ . The solution showed

C.

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pronounced spinnability and was spun as described in Example 1 and converted into rutile threads. _:

EXAMPLE 5 Phosphate-Containing TiOg Filaments 189.7 g of TiCl ^ (1 mol) were added dropwise to 190 g of water with ice-cooling, a TiCl ^ solution containing 24% TiOp being formed. 41 g of H- ^ PO (0.5 mol) were dissolved in this solution and excess water was drawn off in vacuo, so that a solution with 24.7 % TiOp was formed, which was spun from a rotating spinning vessel. The threads were heated to 1000 ° C in air
converted.

Solution with 24.7 % TiOp resulted from a rotating

efäß spunne
1000 ° C heated and thereby in phosphate-containing _{TiO p -Paden}

Example 6 VO _p threads

905 g of ^v o0, - were dissolved in concentrated HCl and, after the addition of 200 ml of ethanol, heated to the boil, as a result of which a deep blue VCIj. Solution was formed. 253.1 g of VOSOj ^ .5HpO (1 mol) were added to this solution and, after dissolving, excess solvent was removed in vacuo until a spinnable solution with 33 ^ VO had formed. The solution was spun from a spinning vessel into a shaft flushed with dry nitrogen at 100.degree. C. and then by heating to 1000.degree. C. in an Np atmosphere. converted into VOp threads.

Example 7 UOp
379.8 g of UCIj ₊ were dissolved in 500 ml of water, mixed _{with 29.4 g of H 2 SOj 4} .- (0.3 mol) and brought to a concentration of 58.5 % U0 _p . The spinning solution obtained on this catfish was processed _{into U0 o threads as described in Example 6.}

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BATH ORIGINAL

Example 8 ThO _? -Paders

100 g of ThCl ^ were dissolved in 300 ml of water and 0.3 mol of H _? S0 ^ per mole of ThOp was added dropwise. After removing the excess water, a yellowish spinnable solution was formed which contained 52.1% ThOp and which after spinning in ThO _? -Thread was transferred.

Example 9 Ti0 _? / Si0 _? - threads

9.15 g of tartaric acid (0.25 mol / TiO _p ) and then 49 g of 30 were added to 100 g of a TiCl ^ solution containing 19.5% _{Ti0 p.} The solution was concentrated on

of 23.4 % TiOp and 17.7 % SiO _p (TiOptSiOp = 1: 1) and spun. The organic constituents were removed therefrom by incineration and a thread with the composition TiOp / SiO _{0 was} obtained.

Example 10 CaTiO ^ threads

A TiCK solution containing ^{21.4; i TiO} p was prepared by dropping TiCl ^ in ice water. 100 g of this solution were mixed with 69.6 g of Ca tartrate CaCj ₊ Pi ^ Og.4HO (CaO: TiO _? = 1: 1). After the Ca tartrate had completely dissolved, excess water was drawn off in vacuo and a spinnable solution containing? 8.9 % CaCTiO _{0 was} obtained, which was processed into CaTiO ^ threads.

Example 11 'Ca0 / Ti0p / Si0 _o -FKden

The spinning solution of TiCl ^, H ₀ O and Ca tartrate described in Example 1C was additionally mixed with 30% SiOp sol (CaO ^ iO ₀ : SiO ^ = 1: 1: 1) and concentrated to a spinnable solution and processed into threads of the r.usamr. composition CaO / TiCp / SiOp.

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BATH ORIGINAL

Example 12 Ti0 ₂ / Al ₂ 0, threads

Threads, in addition to TiO ₂ or Al ₂ ⁰ - * are contained, were from the following spinning solution prepared: by dissolving 10 activated with HgCl_ Al sheet g in an aqueous solution of 40J S 30 j ^ strength sulfosalicylic an Al Sulfosalicylatlösung was obtained . This solution was added to 295 g of a TiCl ^ solution containing 23.8% TiO ₂ in water, brought to a concentration of PO, 9 % TiO ₂ Al ₂ O, and spun. The annealed threads had the composition TiO ₂ .0.21 Al ₂ O ,.

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Claims (6)

Claims; experienced for the production of inorganic fibers, in which threads are drawn from a spinnable solution and then stabilized by a thermal aftertreatment, characterized in that a solution of a metal compound AX ₂ ^ is first produced (A = Si, Ge, Ti, Sn, V, U , Th, Zr, Hf; X = halides, acetate, nitrate, sulfate, hydroxide, alkoxide), the solution is then _{mixed with 0.05 to 1 mol of a compound of the B m} Y type (B = H, Al, Ca, Ba , Sr, Mg, Be, rare earths, Cr, Mn, Fe, Ni, Co, Cu, Zn, Sb, Bi; Y = acid residue; = Valence of the acid residue), the concentration of the obtained Mixture is adjusted so that the concentration of A, calculated as oxide, is 20 to 61 percent by weight, the mixture is spun at temperatures of 15 to 70 ° C. and the fiber obtained is then stabilized by tempering will. 2) Method according to claim 1, characterized in that the metal compound AX ^ per mole of metal A with 0.15 to 0.5 moles of the compound of type B _ffl Y is added. 3) Method according to claim 1 or. 2, characterized in that the metal compound AX ₁ ^ per mole of metal A with 0.05 to 0.5 mol of the compound of the H _m Y type is added. 4) Procedure according to one of the. Claims 1 to 3 »characterized in that BY is sulfuric acid, phosphorous acid, amidosulfonic acid and / or an organic acid which is soluble in concentrated HCl and has a pk value of less than J>, k or a salt of these acids with a Metal B. LeAi2i89 -17- 009842/1767 BATH ORIGINAL AT 5) Method according to claim 4, characterized in that as organic acid benzenesulfonic acid, o-phenolsulfonic acid, Ligninsulfonic acid, sulfosalicylic acid, taurine, glycocolla, citric acid, Malic acid, tartaric acid, malonic acid, oxalic acid, pyruvic acid, lactic acid and / or chloroacetic acid are used will. 6) Method according to one of claims 1 to 5 j in which the Inorganic brine can also be added to the spinning solution. Le A 12 189 - 18 - 009842/1767 Empty soap