DE4233452A1 - Viscous liq. for prepn. of gel-spun fibres - contg. hydrolytically condensed aluminium cpds. - Google Patents

Abstract

Viscous liq. (A) for the prepn. of gel-spun filaments or fibres, comprises one or more partially or fully hydrolytically condensed aluminium cpds. or cpds. of the elements chosen from Ca, Mg, B, Si, transition metals, lanthanides and actinides and/or precondensates thereof, the hydrolytic condensation opt. taking place in the presence of a catalyst and/or solvent using water or moisture. The condensed aluminium cpds. are of formula (I) and/or aluminium alkoxides (Ia) prepd. in situ by reacting (I) with 0.5-2.5 mol. (w.r.t. 1 mol. (I)) alcohol of formula (II) or (III) or mixt. thereof, then complexing the obtd. aluminium cpds. with 3-7 mols. (w.r.t. 1 mol. (I)) lower carboxylic acid (mixt.) or anhydrides thereof, and then hydrolytically condensing the aluminium cpd. complexes. Al (OR*)3 (I), R* = propyl or butyl. R1-X-R2-OH (II), R1-C(X)-R2-OH (III), R1 = 1-10C alkyl or 3-10C cycloalkyl; R2 = 2-4C alkylenyl; X = O, S or NR3; and R3 = H or 1-4C alkyl. USE/ADVANTAGE - (A) are useful for the prepn. of gel-spun filaments or fibres, alumina fibres and multi-oxide component fibres (claimed), for e.g. high temp. insulation (asbestos substitute), catalyst carriers or hot gas filtn. (fitters). Low defect, high tensile strength fibres exhibiting good spun properties are obtd. via a low-cost, simple process that utilises a universal sol soln. for high draw ratio fibres.

Description

The invention relates to viscous, aluminum-containing liquids suitable for the production of gel threads or fibers, a process for their production via the sol-gel process and their use for the production of aluminum oxide-containing inorganic fibers. Spinnable gel threads or fibers are first generated from the liquid (solution) according to the invention, which are precursors of polycrystalline α-Al ₂ O ₃ fibers or corresponding fibers made of multicomponent oxides.

Because of their high strength and high modulus of elasticity Fibers are ideal for producing high bean noticeable fiber composite materials. For this purpose, fibers are considered Continuous fibers, as long staple fibers (a few cm to in) or used as short fibers (up to a few mm), the respective application of the properties of the fibers depends on how B. the fiber length, the number of misses the tensile strength and the spinning properties.

Oxidic, inorganic fibers can e.g. B. Find application to improve the mechanical properties of building components len, for high temperature thermal insulation (asbestos replacement), as Catalyst carrier or for hot gas filtration (soot filter).

The production of inorganic, high temperature resistant oxidic threads and fibers, with the exception of whiskers, is done for. B. from oxidic melts using high temperatures. On the one hand, this has the disadvantage that, due to the high temperatures, great demands are placed on the materials of the production devices and, on the other hand, the molten oxides must have certain viscosities and a not too narrow softening interval so that the drawing of threads and fibers is made possible. These melts therefore always contain SiO ₂ in different amounts. Fibers from e.g. B. pure Al ₂ O ₃ can therefore not be produced in this way.

Methods are also known in which inorganic Fibers are produced by spinnable salt or sol solutions by dry spinning to salt or spun gel fibers and then through these fibers a thermal treatment at a higher temperature in the desired inorganic fibers transferred. E.g. are such The method described in DE-AS 12 49 832, DE-OS 14 94 552 or DE-OS 20 54 573.

Inorganic salt or sol solutions can only be used in whole special cases are spun because the used Solutions have insufficient thread pulling ability. Gel fibers are produced using a dry spinning process get that annealed in normal atmosphere too sinter polycrystalline fibers. The resulting unbe however, peaceful fiber qualities prevent wider ones technical use of the process (Ullmanns Encyclopedia of technical Chemie, 1976, 11, 381-381).

The development and production of Al ₂ O ₃ fibers have been the subject of numerous research activities over the past two decades (HG Sowman, DD Johnson, Oxid fibers from chemical processes, in: Fiber Reinforced Ceramic Composites, Ed.KS Mazdiyasni, Noyes Publications, Park Ridge , NJ, 1990, 123-140; JD Birchall, The preparation and properties of polycrystalline aluminum oxide fibers, Trans. J. Br. Ceram. Soc. 82, 1983, 143-149; HG Sowman, DDJohnson, Cerainic oxide fibers, Cer Eng. Sci. Proc. 6, 1985, 1221; G. Winter, polycrystalline inorganic fiber production, Angew. Chem. 84, 1972, 866). From this work, three different manufacturing processes have been developed, according to which Al ₂ O ₃ fibers are manufactured today. These are:

1. Spinning salt solutions

A viscous, aqueous solution of pure aluminum salt and an organic polymer is spun into threads and sintered (DE 34 47 670 C2).

2. Extrusion of suspensions

Threads are obtained by extrusion of a highly viscous, aqueous Al ₂ O ₃ suspension (particle diameter <0.5 µm).

3. Precursor method (sol-gel process)

From an inorganic or inorganic / organic Polymer precursors are made by melt or dry spinning Gel fibers made.

The spinnable sols are obtained by using aluminum alcoholates, alkyl aluminum compounds, carboxylated aluminum compounds, aluminum acetylacetonates and triethanolamine-modified aluminum alcoholates in certain combinations. To improve spinnability, highly polymeric reagents (spinning aids) such as polyethylene oxide can be added. So z. B. Al (OBu ^s ) ₃ reacted with triethanolamine (JP 01278414 A2; Preparation of alumina fiber from aluminum alkoxide, Colloid Research Institute, Japan). By using the trifunctional amine, larger molecular units can be formed, which hydrolyze and condense to form a spinning mass.

For carboxylation, for example, oxalic acid (process for the production of Al ₂ O ₃ filament yarn, interim report of the BMFT funding project 03 N 104 OA 4, AKZO-Chemie, Research Laboratories Obernburg, 1991) or citric acid (Nishio, Toshiyuki; Fujiki, Yoshinori; Preparation of ceramic fibers by a precursor method, Part 1, Alumina fiber, Nippon Seramikkusu kyokai Gakujutsu Ronbunshi, 98 (11), 1223-30, 1990).

High molecular weight monocarboxylic acids, e.g. B. stearic acid for the partial complexation of alkyl aluminum compounds used (DE-OS 24 08 122). Depending on the solvent Process variant dioxane, toluene, benzene and. a. Use, which, according to today's emphasis on environmental protection, is a problem is to be viewed matically.

Furthermore, from DE-OS 23 25 575 a method for Manufacture of alumina-based fibers after Dry spinning process known in which the salt or Gel fibers before heat treatment with a solution or Dispersion of polyvinyl acetate and optionally one Plasticizers are brought into contact.

Furthermore, DE-OS 21 27 418 viscous, organometallic Known solutions that are used to manufacture anorga African, oxidic, high temperature resistant threads and Fibers should be suitable, and in DE 27 32 290 C2 Process for the production of polycrystalline oxide fibers presented.

However, all of these methods have the disadvantage that they expensive, complex or with the requirements of modern Environmental protection are not compatible, and / or that they are fibers deliver with unsatisfactory quality. Requirements that the fibers must meet z. B. large fiber lengths,  a small number of defects, high tensile strengths and good spinning properties.

The object of the present invention was therefore to To provide a process with which inorganic, oxidic, polycrystalline and high temperature resistant fibers or Alumina-based threads can be provided over long fiber lengths (long fibers), a small number of defects, high tensile strength and good spider properties properties. Furthermore, the process should be simple and universally applicable and inexpensive to implement be. In particular, it was the task of the present Invention, a simple and inexpensive way to provide universally usable target solution, which is about has a high thread pulling capacity and that for manufacturing spinnable gel fibers is suitable. These gel fibers are said to as a precursor for the production of the aforementioned fibers to serve.

This task is solved by viscous liquids from one or more partially or completely hydrolytically condensed compounds of aluminum and optionally other elements from the group Ca, Mg, B, Si, the transition metals, the lanthanides and the actinides, and / or derived from the above compounds Pre-condensates exist, the hydrolytic condensate tion optionally in the presence of a catalyst and / or a solvent by exposure to water or moisture has been carried out. This viscous solution is characterized in that it is partial or complete dig hydrolytically condensed compounds of aluminum contains, which differs from aluminum alcoholates of the formula I.

Al (OR *) ₃ (I)

in which the radicals R * are identical or different and are propyl or butyl,
and / or derived from aluminum alcoholates of the formula I formed in situ from aluminum compounds in that the Al (OR *) ₃ with 0.5 to 2.5 mol, based on 1 mol of Al (OR *) ₃ , of an alcohol or a mixture of alcohols of the formula II or III is implemented,

in which R ^{1 is} a straight-chain, branched or cyclic alkyl radical having 1 to 10 C atoms, R ^{2 is} an alkylene radical having 2 to 4 C atoms, and X is O, S or NR ³ , with R ³ is hydrogen or alkyl having 1 to 4 carbon atoms,
that the resulting aluminum compounds are complexed (carcoxylated) with 3 to 7 moles, based on one mole of Al (OR *) ₃ , a low molecular weight carboxylic acid, a mixture of low molecular weight carboxylic acids or the corresponding anhydrides, and the complexed aluminum compounds are hydrolytically condensed.

Surprisingly, it was found that aluminum ver Bonds of formula I after adding low molecular weight Carboxylic acids do not gel if they have previously been mixed with alcohols of the formula II or III were implemented. After adding Water and after hydrolytic condensation were exceeded obtained spendably spinnable oligomer solutions from spinnable gel fibers, in some cases even quasi Continuous fibers, obtained with the desired properties can be.

Surprisingly, it was found that the Implementation of Al compounds of formula I with alcohols  Formula II and III Al compounds arise, which are Carboxylate, hydrolyze and condense without any problems to let.

The direct implementation of aluminum compounds of formula I, for. B. of Al (OBu ^S ) ₃ , with carboxylic acids, however, leads to solid, insoluble gels that have no fiber-forming ability. The addition of suitable solvents cannot prevent the formation of poorly soluble aluminum compounds. Solvents such as unbranched lower alcohols or ketones react with aluminum compounds of the formula I to form precipitates even without the addition of a carboxylic acid. In contrast, isopropanol, dioxane, tetrahydrofuran, ethyl acetate, chloroform, toluene or triisobutylamine can be mixed in without any problems, but they also did not prevent the formation of solid aluminum compounds during the acid addition.

It is assumed that one of the three reaction-kinetically similar and sterically undemanding alcoholate groups in the compound Al (OR *) ₃ (I) is produced by a reaction-kinetically different and sterically demanding alkoxy group of the type R ¹ -XR in the preparation of the spinning composition according to the invention ² -O- (formula II) or R ¹ -CX-R ² -O- (formula III) is replaced, and that the low molecular weight carboxylic acid the resulting aluminum compound of the type Al (OR *) ₂ (OR ² -XR ¹ ) or Al (OR *) ₂ (OR ² -CX-R ¹ ) complexed.

This is surprising and does not meet expectations because this works with analog silicon compounds Exchange not. i-PrOEtOH and n-BuOEtOH e.g. B. be here even used as a solvent.

Furthermore, it is assumed on the basis of experimental findings men that after carboxylation only 6 times  coordinated aluminum, and not all Alkoxy groups of aluminum through carboxylate groups to be ousted. Otherwise you would be difficult to solve Obtain aluminum carboxylate, which does not contain fiber has more features. This is also surprising and does not meet expectations.

Furthermore, experimental results (IR- spectroscopic investigations) to the conclusion that the Carboxylate groups are not hydrolyzed that after the Hydrolysis the aluminum is only 4-fold coordinated, and that only carboxylate groups, both bridging and chelating, linked to the aluminum atoms. This result is also surprising, given the literature only known chelating aluminum carboxylate groups are.

Crucial for the formation of a spinnable sol seems the correct grading of the chemical To be reactivities of the substituents on the Al central atom. In addition to steric effects, this could be the reason be that from the differently reacting Ab gangsgruppen a connection is obtained, which follows carboxylate, hydrolyze and con can condense.

Another great advantage of the invention is that the production of the dope in a one-pot reaction he follows. Aluminum secondary butylate e.g. B. is a commercial readily available, fluid connection that easily Solvent additive can be processed in indoor air.

Another advantage of the invention is that problematic solvent additives such as dioxane, toluene etc. are not needed. Furthermore, the  Fiber modification required chemical modification without Add a catalyst at room temperature and below simple stirring.

Carboxylation is just as simple. The person in question Carboxylic acid is added to the batch with just stirring at room temperature slowly added, and necessary for hydrolysis water can be in chemically unbound form, e.g. B. vapor, be introduced at room temperature without precipitations occur. The result is a clear, colorless, molecularly disperse spinning mass without spinning tools can be spun into endless gel threads.

Because of the use of low molecular weight carboxylic acids, the gel threads have a high theoretical Al ₂ O ₃ content of up to 34%. This means that the spinning mass contains a low organic content, so that only a slight shrinkage occurs during the thermolysis of the gel threads (to the oxidic fibers).

Furthermore, the dope is non-toxic and can be stored at room temperature for over a year without precipitating. The phase change to α-Al ₂ O ₃ occurs at a temperature of approx. 1125 ° C, and fibers with a diameter of 20 µm are contained. Gel threads for obtaining fibers from multicomponent oxides can be obtained by simple stoichiometric addition of appropriate metal alcoholates.

The radicals R * of the formula I are alkyl groups with three or four carbon atoms, the s-butyl or i-butyl Group is preferred and gives particularly good results.

Preferred embodiments of the alcohols of the formulas II and III are iC ₃ H ₇ -OC ₂ H ₄ -OH, nC ₄ H ₉ -OC ₂ H ₄ -OH, C ₂ H ₅ -NH-C ₂ H ₄ -OH, C ₂ H ₅ -SC ₂ H ₄ -OH, CH ₃ -CO-CH ₂ -OH, CH ₃ -CO-CH (CH ₃ ) -OH or CH ₂ H ₅ -CO-CH ₂ -OH, where n- C ₄ H ₉ -OC ₂ H ₄ -OH provides particularly good results.

The low molecular weight carboxylic acids for complexing the compounds "Al (OR *) ₂ (OR ² -XR ¹ )" or "Al (OR *) ₂ (OR ² -CX-R ¹ )" are used in amounts between 3 and 7 mol, based on one mole of Al (OR *) ₃ , with an amount of 5 moles being preferred and giving particularly good results.

As low molecular weight carboxylic acids for complexing the compounds "Al (OR *) ₂ (OR ² -XR ¹ )" or "Al (OR *) ₂ (OR ² -CX-R ¹ )" are carboxylic acids with 1 to 8 carbon Suitable atoms. Propionic, Valeric, Capronic or Caprylic acid or a mixture thereof are preferred. Acetic acid alone is less useful, but it is also very suitable in mixtures with other acids. Particularly good results are obtained with caproic acid or a mixture of caproic and propionic acids. Furthermore, the carboxylic acids can also be added in the form of their anhydrides.

The carboxylic acids not only serve as carboxylating Agents, but they also act as polar solvents.

The hydrolytic condensation of the Al-containing solution performed by exposure to water or moisture, optionally with the addition of a catalyst and / or Solvent.

For controlled hydrolysis z. B. an apparatus can be used, the moist air with set What serdampfpartialdruck conducts into the spinning mass. The onset and further progress of the condensation reaction is noticeable by an increase in viscosity in the sol and is observed at a constant stirring speed at the corresponding increase in torque of the agitator. In Fig. 1, this apparatus for the production of the inventive dope via the sol-gel process is schematically Darge.

A spinnable sol becomes after a reaction time of three achieved up to four days, with the viscosity increasing steadily and reaches a limit of approx. 5 Pas. The brine according to the invention show spinnability when their Viscosity approaches this limit and they show in Shear jump test pronounced pseudoplastic behavior based on anisotropic, stretched, oligomeric structures points out.

The setting of a corresponding application adjusted viscosity can optionally also by the An inert solvent is added.

By adding suitable heteroalcoholates in corresponding Concentrations can be according to the invention Process also spinning masses for the extraction of fibers Multi-component oxides, e.g. B. from pure mullite or Spinel.

So the Al-containing solution according to the invention before hydrolytic condensation one or more hydrolytic condensable compounds, possibly in precondenses Sized form, such as. B. Silicon compound formulas of formula IV,

R _a (R′′Z) _b SiX _{4- (a + b)} (IV)

in which the detents R, R '' and Z are the same or different and have the following meaning:

R = alkyl, alkenyl, aryl, alkylaryl or arylalkyl,
R ′ ′ = alkylene or alkenylene, where these radicals can be interrupted by oxygen or sulfur atoms or -NH groups,
X = hydrogen, halogen, hydroxy, alkoxy, acyloxy, alkyl carbonyl, alkoxycarbonyl or NR ′ ₂ , with R ′ = hydrogen, alkyl or aryl,
Z = halogen or an optionally substituted amino, amide, aldehyde, alkylcarbonyl, carboxy, mercapto, cyano, alkoxy, alkoxycarbonyl, sulfonic acid, phosphoric acid, acryloxy, methacryloxy, epoxy or Vi nyl group,
a = 0, 1, 2, or 3,
b = 0, 1, 2, or 3, with a + b = 1,2 or 3.

Such silanes are e.g. B. described in DE 34 07 087 C2. The alkyl radicals are e.g. B. straight-chain, branched or cyclic radicals with 1 to 20, preferably with 1 to 10 Carbon atoms, and particularly preferred are lower ones Alkyl residues with 1 to 6 carbon atoms. Specific Examples are methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, i-butyl, n-pentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, dodecyl and octadecyl.

The alkenyl residues are e.g. B. straight-chain, branched or cyclic radicals with 2 to 20, preferably with 2 to 10 Carbon atoms, and particularly preferred are lower ones Alkenyl residues with 2 to 6 carbon atoms, such as. B. Vinyl, allyl or 2-butenyl.

Preferred aryl radicals are phenyl, biphenyl and naphthyl.

The alkoxy, acyloxy, alkylcarbonyl, alkoxycarbonyl and Amino residues are preferably derived from the above Alkyl and aryl residues. Specific examples are methoxy, Ethoxy, n- and i-propoxy, n-, i-, s- and t-butoxy, Methylamino, ethylamino, dimethylamino, diethylamino,  N-ethylanilino, acetyloxy, propionyloxy, methylcarbonyl, Ethylcarbonyl, methoxycarbonyl, ethoxycarbonyl, benzyl, 2-phenylethyl and tolyl.

The radicals mentioned can optionally carry one or more substituents, for. B. halogen, alkyl, hydroxyalkyl, alkoxy, aryl, aryloxy, alkylcarbonyl, alkoxycarbonyl, furfuryl, tetrahydrofurfuryl, amino, alkylamino, dialkylamino, trialkylammonium, amido, hydroxy, formyl, carboxy, mercapto, cyano, nitro, epoxy, SO ₃ H and PO ₄ H ₂ .

The non-hydrolyzable residues of the Si compound IV affect flow the properties of the precursor threads, in particular they are stabilized. So z. B. (meth) acrylic Cross-linking groups and aryl groups reduce the Brittleness. During the subsequent thermal treatment of the precursor threads the whole "organic" is removed and thus these groups have an influence on the structure formation (Porosity, density) of the resulting fiber.

Can be used as further hydrolytically condensable components the reaction medium one or more soluble aluminum, Titanium or zirconium compounds of the following formulas are set, if necessary in precondensed form.

AlR ° ₃ or MX _y R _z

M means titanium or zircon, the residues R °, R and X are the same or different, R ° represents halogen, hydroxy, alkoxy or acyloxy, y is an integer from 1 to 4, in particular special 2 to 4, z stands for 0, 1, 2 or 3, preferably for 0, 1 or 2, and x and R are as in the case of the formula IV Are defined. Regarding the closer (preferred) Defini ions of these residues can be found on the explanations in the hang with the appropriate hydrolyzable silicon connector be referenced. The groups just mentioned can  also in whole or in part by chelating ligands (e.g. acetyl acetone or acetoacetic acid ester, acetic acid) can be replaced.

Al alkoxides and halides are particularly preferred Al compounds. Specific examples are Al (OCH ₃ ) ₃ , Al (OC ₂ H ₅ ) ₃ , AlCl ₃ or AlCl (OH) ₂ .

The Ti and Zr compounds are preferably those in which y is 4. As in the case of the above Al compounds, complexed Ti or Zr compounds can also be used. Additional preferred complexing agents are acrylic acid and methacrylic acid. Specific examples of Zr and Ti compounds that can be used are: TiCl ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OiC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ , Ti (2-ethylhexoxy) ₄ , Zr (OC ₂ H ₅ ) ₄ , Zr (OiC ₃ H ₇ ) ₄ , Zr (OC ₃ H ₇ ) ₄ , Zr (OC ₄ H ₉ ) ₄ , Zr (2- ethylhexoxy) ₄ , ZrCl ₄ and ZrOCl ₂ .

Other hydrolyzable compounds that can be used to produce the dope of the invention are e.g. B. boron trihalides and boric acid esters, such as. B. BCl ₃ , B (OCH ₃ ) ₃ and B (OC ₂ H ₅ ) ₃ .

The table below shows the degree of thread formation some spinning solutions according to the invention. The ability to Thread formation was with three exceptions at room temperature tested using the glass pull-off test.

rating

1 - optically structure-free continuous thread, length 10 m
2 - surface structured continuous thread, length 10 m
3 - gel thread, length 1 m
4 - gel thread, length 10 cm
5 - gel thread, length 1 cm.

The spinning masses J and N were pulled into threads at 50 ° C. the spinning mass O at 100 ° C.

The following table contains the Al₂O₃ content of the used Spinning masses.

In order to be able to demonstrate the suitability of the spinning material according to the invention for a technical manufacturing process, spinning tests were carried out on a pilot dry spinning plant. The system was a piston dry spinning device with a heatable drying shaft and a carrier gas heater that can be regulated up to 250 ° C. The spinning cylinder is designed for small volumes (1700 cm ³ ) and a maximum spinning pressure of 10 MPa and can also be heated. A heatable nozzle head was installed afterwards for better control of the spinning process.

The spinning tests were carried out with masses of the composition Al (OBu ^s ) ₃ / i-PrOEtOH / propionic acid in a molar ratio of 1: 1: 5. This spinning mass has pseudoplastic flow behavior and a strong temperature dependence of the viscosity. Spinning tests were carried out depending on the spinning pressure and temperature. Up to 1000 were drawn into long monofilaments, an attempt being made to set the maximum winding speed attainable up to the thread break. There were significant dependencies between temperature and winding speed. The following table shows the maximum winding speeds at 2 MPa and 3 MPa spinning pressure and at different melt temperatures.

Based on exemplary embodiments, the invention Procedure explained in more detail.

example 1

246.3 g (1.00 mol) of aluminum secondary butylate are mixed with 104.1 g (1.00 mol) of isopropoxyethanol. After a stirring time of 30 minutes, 370.4 g (5.00 mol) of propionic acid are added to the solution with stirring so slowly that a temperature of 25 ° C. can be maintained. After stirring for one hour, water vapor-containing air is introduced through a glass tube at a constantly high stirrer speed (e.g. 400 rpm). About three days later, when the torque of the stirrer motor used reaches a limit, it is switched off and the water-clear, colorless spinning mass is heated to 50 ° C., so that the trapped air can rise and a bubble-free spinning mass is obtained. The spinning mass is heated for better flowability (e.g. 50 ° C), filled in a conventional spinning system and spun at a take-off speed of up to 200 m / min to form kilometer-long monofilaments. The gel thread is then sintered and converts to α-Al ₂ O ₃ fibers at temperatures around 1120 ° C. The spinning mass is stable in storage for over a year.

Example 2

246.3 g (1.00 mol) of aluminum secondary butylate are mixed with 104.1 g (1.00 mol) of isopropoxyethanol are added. After a stir of 30 min, the solution is first 222.2 g (3.00 mol) Propionic acid added so slowly with stirring that a Temperature of 25 ° C can be maintained. After that 121.0 g (2.00 mol) of acetic acid are added dropwise. To One hour of stirring is through a glass tube Air containing water vapor at a constantly high stirrer earth number of revolutions (e.g. 400 rpm) and as in Example 1 described further procedure.

Example 3

246.3 g (1.00 mol) of aluminum secondary butylate are mixed with 118.0 g (1.00 mol) of n-butoxyethanol are added. After a stir 580.8 g (5.0 mol) of caproic acid are added to the solution in 30 minutes added so slowly with vigorous stirring that a  Temperature of 25 ° C can be maintained. The approach is processed analogously to Example 1.

Example 4

246.3 g (1.00 mol) of aluminum secondary butylate with 88.6 g (0.75 mol) of n-butoxyethanol are added. After a stir of 30 min, the solution a mixture of 174.0 g (1.5 Mol) caproic acid and 259.2 g (3.5 mol) propionic acid slowly added with vigorous stirring that a tempe temperature of 25 ° C can be maintained. The approach is going processed analogously to Example 1.

Example 5

246.3 g (1.00 mol) of aluminum secondary butylate are mixed with 118.0 g (1.00 mol) of n-butoxyethanol are added. After a stir of 30 min, the solution a mixture of 348.4 g (3.0 Mol) caproic acid and 120.0 g (2.0 mol) acetic acid so slowly added with vigorous stirring that a temperature of  25 ° C can be maintained. The approach becomes analogous to Example 1 processed.

Example 6

246.3 g (1.00 mol) of aluminum secondary butylate are mixed with 118.0 g (1.00 mol) of n-butoxyethanol are added. After a stir 370.4 g (5.0 mol) of propionic acid become so slow from 30 min added with vigorous stirring that a temperature of  25 ° C can be maintained. The approach becomes analogous to Example 1 processed.

Example 7

156.2 g (1.00 mol) of isopropoxyethanol are added to 269.5 g (1.50 mol) of aluminum secondary butylate. After a stirring time of 30 min, 555.6 g (7.50 mol) of propionic acid are added to the solution so slowly with intensive stirring that a temperature of 25 ° C. can be maintained. Then 208.3 g (1.00 mol) of tetraethoxysilane are added dropwise. The batch is processed in the same way as in Example 1. The result is a gel thread which converts to pure mullite (3 Al ₂ O _{3 *} 2 SiO ₂ ) at 980 ° C.

Claims (15)

1. Viscose, suitable for the production of gel threads or fibers ge liquid, consisting of one or more partially or completely hydrolytically condensed compounds of aluminum and optionally other elements from the group Ca, Mg, B, Si, the transition metals, the lantha niden and the actinides, and / or precondensates derived from the abovementioned compounds, the hydrolytic condensation optionally being carried out in the presence of a catalyst and / or a solvent by the action of water or moisture, characterized in that they are partially or completely contains hydrolytically condensed compounds of aluminum which differ from aluminum alcoholates of the formula I Al (OR *) ₃ (I) in which the radicals R * are identical or different and are propyl or butyl,
and / or derived from aluminum alcoholates of the formula I formed in situ from aluminum compounds

• by reaction of the Al (OR *) ₃ with 0.5 to 2.5 mol, based on 1 mol of Al (OR *) ₃ , of an alcohol or a mixture of alcohols of the formula II or III, in which R ^{1 is} a straight-chain, branched or cyclic alkyl radical having 1 to 10 C atoms, R ^{2 is} an alkylene radical having 2 to 4 C atoms, and X is O, S or NR ³ , with R ³ is hydrogen or alkyl having 1 to 4 carbon atoms,
• by complexing the resulting aluminum compounds with 3 to 7 moles, based on one mole of Al (OR *) ₃ , a low molecular weight carboxylic acid, a mixture of low molecular weight carboxylic acids, or the corresponding anhydrides,
• - And by hydrolytic condensation of the complexed aluminum compounds.

2. viscous solution according to claim 1, characterized in that R * in formula I means s-butyl or i-butyl. 3. Viscous solution according to claim 1 or 2, characterized in that the alcohol of the formula II or III i- C ₃ H ₇ -OC ₂ H ₄ -OH, nC ₄ H ₉ -OC ₂ H ₄ -OH, C ₂ H ₅ -NH-C ₂ H ₄ -OH, C ₂ H ₅ -SC ₂ H ₄ -OH, CH ₃ -CO-CH ₂ -OH, CH ₃ -CO-CH (CH ₃ ) -OH or CH ₂ H _{5 is} -CO-CH ₂ -OH. 4. Viscous solution according to one or more of claims 1 to 3, characterized in that the low molecular weight Car bonic acid is propionic, valerian, capronic or caprylic acid, or an acid mixture containing acetic acid. 5. Viscous solution according to one or more of claims 1 to 4, characterized in that it contains, as further partially or completely hydrolytically condensed compounds, one or more compounds which are obtained by hydrolytic condensation of silicon compounds of the formula IV, optionally in precondensed Derive form, R _a (R′′Z) _b SiX _{4- (a + b)} (IV) in which the radicals R, R ′ ′ and Z are identical or different and have the following meaning: R = alkyl, alkenyl, aryl , Alkylaryl or arylalkyl,
R ′ ′ = alkylene or alkenylene, where these radicals can be interrupted by oxygen or sulfur atoms or -NH groups,
X = hydrogen, halogen, hydroxy, alkoxy, acyloxy, alkyl carbonyl, alkoxycarbonyl or NR ′ ₂ , with R ′ = hydrogen, alkyl or aryl,
Z = halogen or an optionally substituted amino, amide, aldehyde, alkylcarbonyl, carboxy, mercapto, cyano, alkoxy, alkoxycarbonyl, sulfonic acid, phosphoric acid, acryloxy, methacryloxy, epoxy or Vi nyl group,
a = 0, 1, 2, or 3,
b = 0, 1, 2, or 3, with a + b = 1, 2 or 3. 6. Viscous solution according to one or more of claims 1 to 5, characterized in that it contains, as further partially or completely hydrolytically condensed compounds, one or more compounds which are formed by hydrolytic condensation of aluminum soluble in the reaction medium, titanium or Zirconium compounds, optionally in pre-condensed form, derived from the formula AlR ° ₃ or MX _y R _z , in which M means titanium or zirconium, the radicals R °, R and X are identical or different, R ° halogen, hydroxy, alkoxy or acyloxy, y is an integer from 1 to 4, in particular 2 to 4, z is 0, 1, 2 or 3, preferably 0, 1 or 2, and X and R as in the case of formula IV are defined. 7. Process for the production of viscous liquids suitable for the production of gel threads or fibers by partial or complete hydrolytic condensation of one or more hydrolytically condensable compounds of aluminum and optionally other elements from the group Ca, Mg, B, Si, the transition metals , the lanthanides and the actinides, and / or precondensates derived from the abovementioned compounds, optionally in the presence of a catalyst and / or a solvent by the action of water or moisture, characterized in that one or more aluminum compounds of the formula I Al ( OR *) ₃ (I) in which the radicals R * are identical or different and are propyl or butyl,
and / or compounds of the formula I formed in situ from aluminum compounds with 0.5 to 2.5 mol, based on 1 mol of Al (OR *) ₃ , of an alcohol or a mixture of alcohols of the formula II or III, in which R ^{1 is} a straight-chain, branched or in cyclic alkyl radical having 1 to 10 C atoms, R ^{2 represents} an alkylene radical having 2 to 4 C atoms, and X is O, S or NR ³ , where R ³ is hydrogen or alkyl having 1 to 4 carbon atoms,
that the resulting aluminum compounds are complexed with 3 to 7 moles, based on one mole of Al (OR *) ₃ , a low molecular weight carboxylic acid, a mixture of low molecular weight carboxylic acids or the corresponding anhydrides, and that the complexed aluminum compounds are hydrolytically condensed. 8. The method according to claim 7, characterized in that aluminum compounds of the formula I are used in which R * means s-butyl or i-butyl. 9. The method according to claim 7 or 8, characterized in that the alcohol of the formula II or III i- C ₃ H ₇ -OC ₂ H ₄ -OH, nC ₄ H ₉ -OC ₂ H ₄ -OH, C ₂ H ₅ -NH-C ₂ H ₄ -OH, C ₂ H ₅ -SC ₂ H ₄ -OH, CH ₃ -CO-CH ₂ -OH, CH ₃ -CO-CH (CH ₃ ) -OH or CH ₂ H ₅ -CO-CH ₂ -OH is used. 10. The method according to one or more of claims 7 to 9, characterized in that as a low molecular weight Car bonic acid propionic, valerian, capronic or caprylic acid sets, or an acid mixture containing acetic acid. 11. The method according to one or more of claims 7 to 10, characterized in that one or more compounds of the formula IV, optionally in precondensed form, are used as further hydrolytically condensable compounds, R _a (R''Z) _b SiX _{4th - (a + b)} IVin in which the radicals R, R ′ ′ and Z are identical or different and have the following meaning: R = alkyl, alkenyl, aryl, alkylaryl or arylalkyl,
R ′ ′ = alkylene or alkenylene, where these radicals can be interrupted by oxygen or sulfur atoms or -NH groups,
X = hydrogen, halogen, hydroxy, alkoxy, acyloxy, alkyl carbonyl, alkoxycarbonyl or NR ′ ₂ , with R ′ = hydrogen, alkyl or aryl,
Z = halogen or an optionally substituted amino, amide, aldehyde, alkylcarbonyl, carboxy, mercapto, cyano, alkoxy, alkoxycarbonyl, sulfonic acid, phosphoric acid, acryloxy, methacryloxy, epoxy or Vi nyl group,
a = 0, 1, 2, or 3,
b = 0, 1, 2, or 3, with a + b = 1, 2 or 3. 12. The method according to one or more of claims 7 to 11, characterized in that one or more aluminum, titanium or zirconium compounds which are soluble in the reaction medium, optionally in precondensed form, of the formula AlR ° ₃ , as further hydrolytically condensable component or MX _y uses R _z , in which M denotes titanium or zirconium, the radicals R °, R and X are identical or different, R ° represents halogen, hydroxy, alkoxy or acyloxy, y is an integer from 1 to 4, in particular 2 to 4, z stands for 0, 1, 2 or 3, preferably before for 0, 1 or 2, and X and R are as defined in the case of formula IV. 13. The method according to one or more of claims 7 to 12, characterized in that in the mixture of the com plexed aluminum compounds and possibly the white tere condensable components for hydrolytic condensates sation and what to set the desired viscosity blowing in air containing steam. 14. Use the viscous liquid after one or more reren of claims 1 to 6 for the production of gel threads or fibers. 15. Use of the viscous liquid according to one or more of claims 1 to 6 for the production of Al ₂ O ₃ fibers or fibers from multicomponent oxides.