DE2408122A1 - FIBERS AND FEDES MADE FROM ALUMINUM OXIDE OR ALUMINUM OXIDE-SILICON DIOXIDE AND THE METHOD OF MANUFACTURING IT - Google Patents

Description

SUMITOMO CHEMICAL COMPAMT, .LIMITED
Osaka, Japan

"Alumina and alumina-silica fibers and filaments, respectively and process for their production "

Priority: February 20, 1973, Japan, No. 20 568/73 June 5, 1973, Japan, No. 64-23I / 73

The invention relates to fibers and filaments of alumina or alumina-silica having excellent mechanical strength and high heat resistance at high temperatures, for example at 100O ⁰ C or more, and a method for their preparation.

The latest developments in various technical fields, e.g. space travel, require materials with excellent mechanical properties, e.g. high strength and heat resistance.

A common method of improving the properties of

409834/1044

Materials consists in the use of carbon fibers, Metal fibers, e.g. made of tungsten, molybdenum or steel, or composite fibers or filaments obtained by coating the surface of a tungsten filament with boron or silicon carbide, polycrystalline Fibers such as alumina fibers or zirconia fibers or whiskers such as silicon carbide as a reinforcing material. '

Alumina and alumina-silica fibers are known as reinforcing materials for laminates. However, they can also be used for other purposes because they can be used in an oxidizing atmosphere at high temperatures for which conventional carbon fibers or metal fibers are not suitable. Furthermore, they do not lose their excellent mechanical properties, such as high strength even at high temperatures because of their high melting point (above 1590 ^° C.),

These inorganic fibers, for example fibers made of alumina-silica, are usually made by melt spinning an alumina-silica compound. For However, this method requires special equipment for melting because the starting material has a high melting point owns. Furthermore, it is difficult to produce alumina-silica fibers with an alumina content by this method of at least 70 percent, which are characterized by better heat resistance, because such Masses are very difficult to spin. The after this procedure

40 9834/1044

The threads or fibers obtained are short and usually included they are 30 to 50 percent by weight of granular material. Furthermore it is it is inevitable that the product will be contaminated by alkaline compounds, which will reduce the strength evoke properties of the product.

Processes are described as an alternative process for the production of fibers from aluminum oxide or aluminum oxide-silicon dioxide in which a precursor fiber is made from an aqueous solution of an aluminum compound, which is a silicon compound can be incorporated. The precursor fibers are manufactured using the dry spinning process and then the product obtained is calcined. With some

man

these known processes only obtain short fibers or the processes cannot be carried out on an industrial scale. In other of these processes, the starting material is not only expensive, but also requires numerous cumbersome treatment steps in order to convert it into a spinnable state. After all, there are difficulties associated with spinning that have not yet been resolved. All known methods have in that the fibers of alumina or alumina-silica have the decisive disadvantage no sufficient density, and only an unsatisfactory strength since the precursor fiber _#i a low content of alumina or alumina-silica, such as greater than about 25 Gewichtsprοzent having.

The invention is based on the object of fibers and threads

ΔΠ983Α / 1044

Alumina and alumina-silica with excellent Heat resistance, mechanical strength and fiber structure to create that can be produced by a simple process from easily accessible starting compounds. These The object is achieved by the invention.

The invention thus relates to fibers and threads made from aluminum oxide or aluminum oxide-silicon dioxide, which can be produced by spinning a solution of a polyaluminoxane with basic building blocks the general formula

-Al-O- I

in which X is a halogen atom, an alkyl, alkoxy, carboxy, hydroxy or represents an optionally substituted phenoxy group, or a mixture of the polyaluminoxane and one or more silicon compounds and calcining the filaments or fibers obtained.

The invention also relates to a method for producing the fibers and threads from aluminum oxide or aluminum oxide-silicon dioxide, which is characterized in that a solution of a polyaluminoxane with basic building blocks of the general formula

-Al-ΟΙ
Y

in which Y is a halogen atom, an alkyl, alkoxy, carboxy, hydroxy or an optionally substituted phenoxy group, or a mixture of the polyaluminoxane and one or

409834/1044

melireren Sxliciumverbindungen spun and the threads obtained or fibers calcined.

The polyaluminoxane used in the process of the invention is preferably in an organic solvent such as diethyl ether, Tetrahydrofuran, dioxane, benzene or toluene, dissolved to a viscous solution with good spinnability ^ Preferably the spinning solution has a viscosity of 1 to 5000 poise, measured at room temperature.

The main chain of the polyaluminoxane used according to the process consists of basic building blocks, the aluminum and oxygen atoms contain. Therefore this compound has a high content of aluminum oxide. For example, polyethylaluminoxane contains about 71 Weight percent alumina. The silicon compound, which optionally is mixed with the polyaluminoxane, a have high carbon dioxide content. For example contains Dimethylpolysiloxane about 81 weight percent silica. From the compounds used according to the process light threads and fibers made of alumina and alumina. Extremely high density silica produce that doesn't are porous and have a very high mechanical strength. "

The polyaluminoxane used in the process is a polymer with basic building blocks of the general formula

-Al-OI
Y

in which X is an alkyl radical, such as methyl, ethyl, propyl or

409834/1044

Butyl group, an alkoxy group, such as the xthoxy, propoxy or Butoxy group, a carboxy group such as formyloxy, acetoxy, Propionyloxy or butyryloxy group, a halogen atom such as a Denotes fluorine or chlorine atom, a hydroxyl group or an optionally substituted phenoxy group. As a substituent for the phenoxy group there are, for example, methyl, ethyl or propyl groups in question. The radical Y in the polymer can consist of one or more of the aforementioned groups.

Polyaluminoxanes are preferably used in the process according to the invention with an aluminum oxide content of at least 10, in particular at least 20 percent by weight. The alumina content means the numerical value that is calculated according to the following equation:

■ 51

Aluminum oxide content = ■ χ 100%

Molecular weight of the basic building block (-A1-0-)
I.
Y

If Y represents two or more groups of the aforementioned type, the molecular weight means the average molecular weight. When using a polyaluminoxane with an aluminum oxide content of less than 10 percent by weight, it is very difficult to find usable threads and. Fibers made of aluminum oxide or To produce alumina-silica with excellent strength, although this is not impossible.

If the radical Y is an alkyl radical, this radical can generally 1 to about 33 carbon atoms, but preferably contain at most about 15 carbon atoms. If the

_l 409834/1044

Radical Y denotes an alkoxy radical, this radical can in general at most about 32 carbon atoms, but preferably at most Contains 14 carbon atoms. If the rest of Y is a cooking "boxy rest means, this radical preferably contains no more than 31 carbon atoms, in particular no more than 20 Carbon atoms. When the radical Y is a substituted phenoxy group means, the substituent preferably contains no more than 26 carbon atoms, in particular no more than 8 carbon atoms atoms. Particularly preferred radicals Y are alkyl, alkoxy and carboxy radicals each having a maximum of 4 carbon atoms, there these polyaluminoxanes have a high aluminum oxide content and the precursor filaments made from these compounds readily hydrolyze in the manner described below permit.

It is known that polyaluminoxanes are produced by partial hydrolysis of organoaluminum compounds such as triethylaluminum, triisopropylaluminum, Tributylaluminum, aluminum triethoxide or aluminum tributoxide, or by substituting the remaining ones Group of the polyaluminoxane produced by other suitable groups. The organoaluminum compound is preferred first or the silicon compound, which may also be used, is purified by distillation.

The degree of polymerization of the polyaluminoxanes used according to the process can be in a relatively wide range. A degree of polymerization of 2 or more is sufficient. With regard to be on the ease of the polymerization reaction

409834/1044

Compounds with a degree of polymerization of at most 1000 are preferred. Compounds with a degree of polymerization are particularly preferred from 10 to 200.

The polyaluminoxane generally dissolves in organic solvents, such as diethyl ether, tetrahydrofuran, dioxane, benzene or toluene. A viscous solution is obtained which, when appropriate Lets concentration spin well. The relationship between the concentration and the spinnability of the solution depends on the type of polyaluminoxane, the degree of polymerization, the type of solvent and the type and amount of the silicon compound optionally used. Preferably becomes a spinning solution with a viscosity of 1 to 5000 poise, measured at room temperature. The spinning solution must therefore be produced in such a way that its viscosity is in the aforementioned range lies. Particularly preferred polyaluminoxanes for the inventive Process contain 1 to 20 mol percent, in particular 1 to 10 mol percent of the radical Y, which is a palmitoyloxy and / or stearoyloxy radical, since such polyaluminoxanes Can be spun excellently.

A polyorganosiloxane is preferably used as the silicon compound with basic building blocks of the general formula

Si-O-

Ί 2
used in which R and R are the same or different and are hydrogen atoms, alkyl radicals having 1 to 6 carbon atoms, such as

409834/1044

the methyl, ethyl, propyl and butyl groups, alkenyl radicals with 1 bo, s 6 carbon atoms, like the vinyl group, alkoxy radicals with 1 to 6 carbon atoms, such as the ethoxy group, phenyl groups or chlorine atoms. Polysilicic acid esters are also used with basic building blocks of the general formula

OR ⁵

-Si-O-

3 4
preferred in which R and R are the same or different and are hydrogen atoms, alkyl radicals with 1 to 6 carbon atoms, such as the methyl, ethyl, propyl and butyl groups, alkenyl radicals with 1 to 6 carbon atoms, such as the Tiny! group, phenyl groups or chlorine atoms mean. Furthermore, organosilanes of the general formula R ^ Si (0R ⁶ ) ^ _ _{n are} preferred, in which Ή? and R are identical or different and represent hydrogen atoms, alkyl radicals with 1 to 6 carbon atoms, such as the methyl and ethyl group, alkenyl radicals with 1 to 6 carbon atoms, such as the vinyl group, phenyl groups or chlorine atoms, and η is an integer with a value of 1 to 4 ·. Finally, silica

n π

esters of the general formula Si (OR X preferred, in which R ' denotes a hydrogen atom, an alkyl radical having 1 to 6 carbon atoms or a phenyl group. Other silicon compounds can also be used.

The silicon compound is preferably in.der solution of the poly aluminoxans dissolved homogeneously. However, it can also be dispersed in the solution. A silicon compound is preferred

40983 4/1044

used, which gives a spinnable solution when it is dissolved in the solution of the polyaluminoxane. However, this is not the case. vital.

The maximum content of the silicon compound that can be incorporated in the solution of the polyaluminoxane depends on the spinnability the silicon compound itself. If a non-spinnable silicon compound is used in too large an amount, the spinnability of the solution deteriorates so much that the solution does not turn into threads after any of the conventional spinning processes lets spin. The aforementioned silicon compounds are used in such a maximum amount that the silicon dioxide content after calcining the alumina-silica fibers is 60 weight percent. Optionally, two can or more silicon compounds are incorporated into the solution of the polyaluminoxane.

Preferably, the spinning solution is also a small amount of a lithium, beryllium, boron, sodium, magnesium, phosphorus, Potassium, calcium, titanium, chromium, manganese, yttrium, zirconium, barium, lanthanum or tungsten compound or a mixture of at least two of these compounds incorporated in order to improve various properties of the threads or fibers. The spinning a solution of the polyaluminoxane or a mixture of the polyaluminoxane and the silicon compound is preferred carried out according to the dry spinning process, but other conventional spinning processes, such as the centrifuge spinning process, can also be used or the blow spinning process is used

40983W 1 044

will. The spinning is usually carried out at room temperature. If necessary, the spinning solution can also be raised to a temperature below the boiling point of the solvent used be heated. Preferably, the spinning is carried out under such conditions that that contained in the spun thread Solvent can be separated during or after spinning. However, such a separation is not essential required when very thin threads are spun.

When spun in air, the polyaluminoxane component gradually hydrolyzed in the precursor thread by the humidity in the air will. In this way, organic components can be used gradually lost, whereby the content of aluminum oxide in the precursor thread increases and the mechanical properties of the filaments after calcining can be improved. Accordingly, when a silicon bond is also used, it is preferred uses a compound which is easily hydrolyzed, such as a polysilicic acid ester. Preferably will too the precursor thread is treated with steam or an acidic reacting aqueous solution during or after spinning in order to hydrolyze it to accelerate.

The precursor initially produced in the process according to the invention. sor thread can have an average diameter, from 1 to 100 / u, but it is not limited to this range. The aluminum oxide or aluminum oxide-silicon dioxide precursor thread is in a homogeneous and continuous state in which the aluminum oxide or silicon dioxide

^L ■ J

409834/1044

is contained in high concentration. Therefore, threads or threads can be made from such a precursor thread by calcining. Alumina or alumina-silica fibers with produce excellent improved properties. The precursor thread also has excellent strength. If he For example, if it is processed into textile fabrics and then calcined, the corresponding fabrics are obtained.

The precursor thread obtained by contacting with moisture is not melted by heating. It can therefore be calcined in a gas atmosphere containing oxygen or free oxygen, for example in air, without losing its thread shape. Containing atmosphere by calcining at temperatures of about 70o C ⁰ in a free oxygen such as air, is obtained from the precursor thread a Aluminiumcxid- or alumina-silica yarn, and by calcining at temperatures of about 1OOO ° C to obtain a transparent Thread with excellent strength.

Upon calcining the precursor thread in a free oxygen containing gas atmosphere, for example in air, losing water and the organic components at temperatures of about .600 ⁰ C, and the strength of the yarn increases with increasing calcination temperature. When calcining a thread which contains pure aluminum oxide, the thread-forming T-aluminum oxide phase is converted into the oil-aluminum oxide ^{phase at temperatures of about 1000 to 1100 ° C.} This results in a significant reduction in the strength of the thread. If on the other hand a

_J 409834/1044

If a thread containing aluminum oxide and silicon dioxide is calcined, the transition temperature can be shifted to a higher temperature range as the silicon dioxide content increases. With a silica content of 25 to 28 percent by weight, the transition temperature is about 1550 ° C. With further increasing silica content, the transformation temperature sounds again and a silica content of about 40 weight percent, the conversion temperature is about 1400 ⁰ C and at a silica content of about 50 weight percent to lie at about 1200 ⁰ C

In order to produce filaments from aluminum oxide and silicon dioxide with excellent strength, the CaIcination temperature can be below the aforementioned transformation temperature. For certain purposes, e.g. for thermal insulation, where there is more on. The heat resistance of the threads is more important than their mechanical properties, the threads are preferably sintered at a higher temperature in order to avoid further scuffing. In this case, the heat treatment temperature may be above the aforementioned transition temperature, and it may be lower by about 50 ⁰ C as the melting point which is at temperatures of I7OO to 205O ⁰ C, depending on the amount ratio of alumina to silica in the filament. The heat treatment temperature or CaIciniertemperatur may thus be in the range of about 7OO to 2000 ⁰ C.

When threads are heated to temperatures of about 1000 ^° C. up to the transition point, the T-aluminum oxide phase and

4098 3 4/1044

fff: '

form the mullite phase when the silicon dioxide content is at most 28 percent by weight. With a silicon dioxide content of more than 28 percent by weight amorphous silicon dioxide and mullite phase are formed. These phases can occur at the transition temperature or above it into the Ύ -aluminium oxide phase and the mullite phase or the cristobalite and mullite phase.

Correspondingly, threads made of alumina or alumina-silica may be used with high thread strength, which is 100 to 72 percent by weight alumina and 28 to 0 percent by weight silica contain no reflections in the X-ray diffraction diagram that indicate <jL -aluminium oxide. Also allowed Alumina-silica filaments that are less than 72 percent by weight Contain aluminum oxide and more than 28 percent by weight silicon dioxide, no reflections in the X-ray diffraction diagram that indicate cristobalite.

When the filaments or fibers are made of alumina or alumina-silica If these conditions are met, filaments are obtained which, in the case of pure aluminum oxide, have the following mechanical properties Have properties:

2 Tensile strength about .10 to 15 t / cm

2 tensile strength module ■ approx. 1000 to 1500 t / cm

a thread diameter of 10., tu

These values also increase with increasing silica content. With a silica content of about 10 to 25 percent by weight is the

2 tensile strength about 25 to 30 t / cm and the

2 Tensile modulus about 2500 to 3500 t / cm.

409834/1044

If the silicon dioxide content increases further, take 1, (leT ^ tensile

strength modulus gradually decreases. With a silica content of about 50 percent by weight "it is only about 1300 t / cm With increasing silicon dioxide content, the tensile strength modulus of the thread drops to a value of about 700 t / cm and corresponds to thus roughly the strength value of a thread made of silicon dioxide *

In order to produce the threads and fibers from aluminum oxide or aluminum oxide-silicon dioxide, the precursor thread can be used according to the invention calcined either in an inert gas atmosphere or under reduced pressure and then in a free one Oxygen-containing atmosphere are treated further, whereby organic or carbon-containing substances are burned off will.

Preferably the thread is made of alumina or alumina-silica further calcined in a reducing atmosphere to improve various properties of the thread. Finally, the thread is kept under tension during the calcination step to produce a thread with excellent to maintain mechanical properties.

The threads and fibers made of aluminum oxide which can be produced according to the invention and alumina-silica are suitable for reinforcing synthetic resins such as thermoplastic resins and thermosetting synthetic resins, as well as reinforcing threads or fibers for metals due to their excellent heat resistance

409834/1044

ORIGINAL INSPECTED

2A08 1 22

strength and mechanical strength. The threads and fibers that can be produced according to the invention are also valuable as heat insulators at high temperatures, for example above 1000 ^° C., because they can be used in air at these high temperatures.

The examples illustrate the invention.

Example i

1 mol of monoisopropoxydiethylaluminum is dissolved in 600 ml of diethyl ether. The mixture is heated in an oil bath at 40 ⁰ C. The diethyl ether distilling off at this temperature is condensed in a condenser, introduced into a container containing 1 mol of water, moistened thereby and then returned to the reaction vessel. Within 8 hours, 1 mol of water is consumed and the partial hydrolysis of the monopropoxydiethylaluminum is complete. A polyisopropoxyaluminoxane with a degree of polymerization of 130 is obtained. The polymer solution is evaporated to a concentration of 70 percent by weight of polyaluminoxane. The viscosity in the solution obtained is 500 poise, measured at room temperature.

The solution obtained is used as a spinning solution. After this The solution is degassed at room temperature through a spinneret with a diameter of 100 / u. extruded and the extruded The thread is passed at a speed of 50 m / min Air coiled. A transparent precursor thread with a diameter of 15 m is obtained. The thread will be at

_J 409834/1044

^Γ 17 - ^π

is increased /

a temperature that goes from room temperature to 95O ° C / at one rate calcined at 3OO ° C / hour in air. It will a transparent thread made of aluminum oxide with extremely high 'strength. The thread diameter is 10 / u, the

ρ
Tensile strength 15.1 t / cm and the tensile modulus 1480 t /

cm. Based on the X-ray diffraction diagram "the thread consists of Ύ -aluminium oxide .

Example 2

1 mol of triethylaluminum is dissolved in 60.0 ml of dioxane and a solution of 100 ml of dioxane containing 1 mol of water is added dropwise over the course of 2 hours. The partial hydrolysis product obtained is a polyethylaluminoxane with a degree of polymerization of 4-0. The temperature of the reaction mixture is set to 50 ^° C. during the reaction. 0.5 mol of stearic acid is then added to the reaction mixture, as a result of which 0.3 mol of ethyl groups in the polyethylaluminoxane are replaced by stearoyloxy groups. A 60 weight percent solution of the polymer has a viscosity of 230 poise, measured at room temperature. The solution is spun according to Example 1 to form a precursor thread with a diameter of 12 yes. The thread is completely stable even when standing in the air. The thread is calcined with increasing temperature from room temperature to 95O ° C at a rate of 600 ° C / hour. A transparent thread made of aluminum oxide with extremely high strength is obtained. The thread diameter after calcining is 8 / u, the tensile strength 16.8 t / cm and the tensile modulus 1550 t / cm ² .

4098 34 / 1Ü44

• - 18 -

Example 3

The polyethylaluminoxane prepared according to Example 2 is mixed with 0.1 mol of stearic acid and 0.9 mol of isopropanol. Through this a total of 1 mole of ethyl groups are replaced by stearoyloxy groups and isopropoxy groups in the polyethylaluminoxane. The mixture is in 51 g of ethyl silicate of the formula

dissolved and evaporated to a concentration of 60 percent by weight polyaluminoxane. The viscosity of the solution obtained is 200 poise, measured at room temperature. According to Example 1, this solution is spun into a transparent precursor thread with a diameter of 15 μm. Der.erhaltene precursor yarn is treated for 3 hours at 6O ⁰ G with saturated steam, and then calcined with increasing temperature from room temperature to 1200 ⁰ C at a rate of 300 ⁰ C / hour in air. A transparent thread of alumina-silica containing 20 percent by weight silica is obtained. This thread has a diameter of 10 yu, a tensile strength of 30.1 t / cm and a tensile strength module of 3320 t / cm ² . Even when heated to 1500 ^° C., the thread still remains transparent and retains its high mechanical strength.

The process described above is repeated, but the precursof thread is calcined without treatment with steam.

409834 / 1Ü44

2 The thread obtained has a tensile strength of 16.3 t / cm and

2 has a tensile modulus of 25 ^ 0 t / cm.

The threads obtained according to the two embodiments exist due to the X-ray diffraction diagram of Ύ -alumina and Mullite.

Example 4

Benzene is added to a solution of the polyisopropoxyaluminoxane prepared according to Example 1 in diethyl ether. The diethyl ether is distilled off from the mixture until the solution has a polyaluminoxane concentration of 55 percent by weight. The solution is mixed with 27 g of polydimethylsiloxane and spun according to Example 1 to form a transparent precursor thread with a diameter of 15M. The precursor yarn is calcined with increasing temperature from room temperature to 1200 ⁰ C at a rate of J500 ° C / hour in air. A transparent thread of alumina-silica containing 30 percent by weight silica is obtained. This thread has a diameter of 10 / u and a tensile strength of 23.2 t / cm

and a tensile modulus of 2780 t / cm. In the X-ray diffraction diagram of the thread becomes the main mullite reflection and found virtually no reflection attributable to amorphous silica. Even when heated at 1550 ° C the thread remains transparent.

Example 5 A solution of a polyaluminoxane in which 0.1 mole percent of the

409834/1044

organic residues stearoyloxy residues and 0.9 mole percent isopropoxy residues represent (degree of polymerization 40), in dioxane is with Y-methacryloyloxypropyl-trimethoxysilane in such a weight ratio offset that the calcined thread contains 10 weight percent silicon dioxide. The mixture will be up to one Polyaluminoxane concentration of 50 percent by weight evaporated and left to stand for 12 hours "at room temperature. After that, that's T-methacryloyloxypropyl-trimethoxysilane polymerized. It will obtained a viscous solution which can be spun excellently. The viscosity is 200 poise at room temperature. the The solution obtained is spun according to Example 1 to form a transparent precursor thread with a diameter of 10 / u.

The precursor yarn is calcined with increasing temperature from room temperature to 600 ⁰ C at a rate of 300 ° C / hour under nitrogen as protective gas. Then, the calcination is continued in air with increasing temperature up to 1200 ⁰ C. A transparent thread made of alumina-silica with high mechanical strength and a diameter of 6 / u is obtained.

Example 6

The solution of polyaluminoxane in dioxane used in Example 5 is mixed with tetraethoxysilane in such a quantitative ratio added that the calcined thread contains 50 percent by weight silicon dioxide. The solution will come up to a concentration Polyaluminoxane evaporated from 60 percent by weight and then into a precursor thread with a diameter of 15 / g. spon-

409834/1 Ü44

nen. The obtained precursor yarn is treated for 2 hours at 60 ° C with steam and then calcined with increasing temperature from tree temperature to 115o ° C at a rate of 300 ⁰ C / hour in air. A thread of alumina-silica with a diameter of 10 / U is obtained.

This thread has a tensile strength of 27.8 t / cm and a tensile

strength modulus of 1260 t / cm. In the X-ray diffraction diagram. will just the reflections of mullite and amorphous silica ' observed.

409834/1 over 4 4

Claims (1)

. - 22 - 1. fibers and threads made of aluminum oxide or aluminum oxide-silicon dioxide, produced by spinning a solution of a "poly aluminoxane with basic building blocks of the general formula -Al-O- in which Y is a halogen atom, an alkyl, alkoxy, Carboxy ™, Hydroxy or an optionally substituted phenoxy group, or a mixture of the polyaluminoxane and one or more silicon compounds and calcining the resulting precursor threads or fibers. 2. Process for making the fibers and filaments from alumina or aluminum oxide-silicon dioxide according to claim 1, characterized in that a solution of a polyaluminoxane with basic building blocks of the general formula -Al-O- in which Y is a halogen atom, an alkyl, alkoxy, carboxy, hydroxy or an optionally substituted phenoxy group means, or a mixture of the polyaluminoxane and one or more Siliciumverbxndungen spun and the obtained threads or fibers calcined. 3. The method according to claim 2, characterized in that a spinning solution is used 'which additionally contains one or more lithium, beryllium, boron, sodium, 409834/1044 ο / η ρ ι ο O Magnesium, phosphorus, potassium, calcium, titanium, chromium, Contains manganese, yttrium, zirconium, barium, lanthanum or tungsten compounds. 4. The method according to claim 2, characterized in that one a polyaluminoxane with an alumina content of at least 20 percent by weight is used, which is calculated according to the following equation: Aluminum oxide content = ■ ^ x 100 (%) Molecular weight of the basic building block (-A1-0-) where Y has the meaning given in claim 1 and if Y represents two or more groups, the molecular weight of the basic building block is an average value. 5. The method according to claim 2, characterized in that one a polyaluminoxane is used in which Y is an alkyl radical with 1 to 15 carbon atoms, an alkoxy radical with 1 to 14 Carbon atoms, a carboxy radical with a maximum of 20 carbon atoms, a phenoxy group or a substituted phenoxy group having at most 8 carbon atoms in the substituent or is a mixture of at least two of the groups. 6. The method according to claim 2, characterized in that a polyaluminoxane is used in which Y is a methyl, ethyl, Propyl, butyl, ethoxy, propoxy, butoxy, formyloxy, Acetoxy, propionyloxy or butyryloxy group or a mixture is from at least two of the groups. 409834/1044 ORIGINAL INSPECTED 7. Procedure according to. Claim 2, characterized in that one a polyaluminoxane is used, "in which the organic radical 1 to 20 mole percent stearoyloxy and / or palmitoyloxy group η contains. 8. The method according to claim 2, characterized in that a polyaluminoxane with a degree of polymerization of 10 to 200 starts. 9. The method according to claim 2, characterized in that one "as a solvent for the polyaluminoxane diethyl ether, tetrahydrofuran, Dioxane, benzene, toluene, xylene or their mixture is used. 10. The method according to claim 2, characterized in that one as a silicon compound a polyorganosiloxane with basic components the general formula Si-O
² 1 2
is used in which R and R are identical or different and denote hydrogen atoms, alkyl radicals with 1 to 6 carbon atoms, alkenyl radicals with 1 to 6 carbon atoms, alkoxy radicals with 1 to 6 carbon atoms, phenyl groups or chlorine atoms. 409834/1044 11. Procedure according to. Claim 2, characterized in that one as silicon compound a polysilicic acid ester with basic building blocks of the general formula OR ³
-Si-O- OR ⁴ is used in which R- * \ xnd R are identical or different and denote hydrogen atoms, alkyl radicals with 1 to 6 carbon atoms, alkenyl radicals with 1 to 6 carbon atoms, phenyl groups or chlorine atoms. 12. The method according to claim 2, characterized in that that'man the silicon compound is an organosilane of the general formula starts in the Ή? and R are identical or different and represent hydrogen atoms, alkyl radicals with 1 to 6 carbon atoms, alkenyl radicals with 1 to 6 carbon atoms, phenyl groups or chlorine atoms and η is an integer with a value of 1 to 4. 13. The method according to claim 2, characterized in that one a silicic acid ester of the general formula as the silicon compound Si (OR ⁷ ) ^ uses, in which R 'is a hydrogen atom, an alkyl radical with Represents 1 to 6 carbon atoms or a phenyl group. 409834/1044 -. Process according to claim 2, characterized in that one as the silicon compound, an ethyl silicate of the formula is used, in which η is an integer with a value of at least 1 means. 15 · The method according to claim 2, characterized in that a spinning solution with a viscosity of 1 to 5000 poise, measured at room temperature. 16. The method according to claim 2, characterized in that the precursor thread is heated ^{to temperatures of 700 to 2000 0 G.} 17. The method according to claim 2, characterized in that one the heating is carried out in oxygen or a gas containing free oxygen. 18. The method according to claim 2, characterized in that the precursor thread obtained during or after spinning treated with steam or an acidic solution. 19. Fibers and threads according to claim 1, containing 72 to 100 percent by weight Alumina and 0 to 28 weight percent silica, practically none in the X-ray diffraction diagram J 409834/1044 Have reflection indicative of e * -aluminium oxide. 20 "lasers and threads according to claim 1, containing 40 to 72 percent by weight Aluminum oxide and 28 "to 60 percent by weight silicon dioxide, which are practical in the X-ray diffraction pattern" have no reflection indicative of cristobalite. 409834 /