BRIEF DESCRIPTION OF THE INVENTION

The costs for the production of textile fibers with wet-milled flame retardants according to AT 510 909 A1 are very high and yet the mechanical properties of these fibers are not optimal. The object of the present invention is therefore to provide an oxidized condensate of THP with a compound comprising an NH 2 radical or NH 3 or with NH 3 , which is less expensive to produce the desired particle size and provides fibers with better mechanical properties.

This object is achieved by a method comprising the steps

(a) Reacting at least one tetrakishydroxyalkylphosphonium compound with NH 3 or with at least one nitrogen compound comprising at least one NH 2 or at least two NH groups, preferably selected from the group consisting of urea, thiourea, biuret, melamine, ethylene urea, guanidine and dicyandiamide, in order to form a precondensate obtained, the molar ratio of the tetrakishydroxyalkylphosphonium compound to the nitrogen compound in the range from 1: (0.05 to 2.0), preferably in the range from 1: (0.5 to 1.5), particularly preferably in the range from 1: ( 0.65 to 1, 2),

(b) Cross-linking of the precondensate obtained in process step (a) with the aid of ammonia,

(c) Oxidation of the cross-linked polymer obtained in step (b) by adding an oxidizing agent to obtain the flame retardant, which is characterized in that

in step (b) the precondensate from step (a) and the ammonia are each sprayed by means of a nozzle into a reactor space enclosed by a reactor housing at a common collision point.

In one embodiment, it is provided that in step (b) the precondensate from step (a) and the ammonia are each sprayed by means of a nozzle into a reactor space enclosed by a reactor housing at a common collision point, the resulting products through an opening (2) be removed from the reactor housing by negative pressure on the product and gas outlet side.

In an alternative embodiment variant, it is provided that in step (b) the precondensate from step (a) and the ammonia are in each case injected into a reactor space enclosed by a reactor housing onto a common collision point by means of a nozzle, with an opening into the reactor space Gas, an evaporating liquid, a cooling liquid or a cooling gas is introduced to maintain the gas atmosphere inside the reactor, in particular at the point of collision of the liquid jets, or to cool the resulting products, the resulting products and excess gas from the reactor housing through a further opening be removed by positive pressure on the gas inlet side or by negative pressure on the product and gas outlet side (see also Fig. 1).

Surprisingly, it was found that the reaction of the precondensate with ammonia can be accelerated so much by using a microjet reactor technology that the precipitation of the crosslinked reaction product already takes place at the point of collision of the microblasts, which contain the precondensate on the one hand and the ammonia on the other. Due to the high speed of the micro-jets, the two educts are mixed so intensively at the collision point and the reaction speed of the crosslinking is accelerated so much that the flame retardant polymer is obtained in solid form as a nano / micro dispersion. The complex and therefore very expensive wet grinding can thus be avoided. With regard to the precise description of such a reactor and further details, reference may be made to EP 1 165 224 B1.

The hydroxyalkyl groups of the tetrakishydroxyalkylphosphonium compounds are preferably hydroxymethyl, hydroxyethyl, hydroxypropyl or hydroxybutyl groups, so that in this case the alkyl radical of the tetrakishydroxyalkylphosphonium compound is selected from the group consisting of methyl, ethyl, propyl or butyl. Furthermore, the tetrakishydroxyalkylphosphonium compounds are preferably salts.

The at least one tetrakishydroxyalkylphosphonium compound is particularly preferably a tetrakishydroxymethylphosphonium compound (THP), with the general formula (P + (CH 2 OH) 4) t X " , or mixtures of such compounds, where

X " denotes an anion and t the valence of this anion. Here t can denote an integer from 1 to 3. Suitable anions X " are, for example, sulfate, hydrogen sulfate, phosphate, mono- or dihydrogen phosphate, acetate or halogen anions such as fluoride, chloride and bromide.

The at least one nitrogen compound which is reacted with the tetrakishydroxyalkylphosphonium compound in process steps (a) and (b) is generally one compound, two compounds, three compounds or more compounds selected from the group consisting of ammonia, urea, thiourea, biuret, Melamine, ethylene urea, guanidine and dicyandiamide. According to a preferred embodiment of the invention, the nitrogen compound is urea. According to a particularly preferred embodiment of the invention, at least one nitrogen compound selected from the group consisting of urea, thiourea, biuret, melamine, ethyleneurea, guanidine and dicyandiamide is reacted in process step (a) and crosslinked with ammonia in the subsequent process step (b).

According to a preferred embodiment of the invention, the reaction in process step (a) is carried out in a solvent. The preferred solvent used is water. The content of the compounds to be reacted in process step (a) can vary over wide ranges and is generally 10% by weight to 90% by weight, preferably 20% by weight to 40% by weight, based on the total mass of the process step (A) reaction mixture used which contains at least the two compounds to be reacted and the solvent.

The molar ratio of the tetrakishydroxyalkylphosphonium compound to the nitrogen compound can vary over wide ranges and is generally in the range from 1: (0.05 to 2.0), preferably 1: (0.5 to 1.5), particularly preferably 1: ( 0.65 to 1, 2). The targeted selection of this molar ratio ensures that the flame retardant produced according to the invention does not dissolve, or only dissolves to a small extent, in the solvents used in the production of flame-retardant cellulose fibers.

Process step (a) is generally carried out at a temperature in the range from 40 to 120 ° C., preferably at a temperature in the range from 80 to 100 ° C. over a period of from 1 to 10 hours, preferably over a period of from 2 to 6 hours.

According to an advantageous embodiment of the invention, one or more dispersants are added to the polymer after carrying out process step (a) and before carrying out process step (b), and thus before carrying out the crosslinking by means of ammonia. These dispersants are preferably selected from the group polyvinylpyrrolidone, Ci4-Ci 7-Alkylsulfonaten, hydroxypropyl cellulose (HPC), polyethylene glycol (PEG), modified polycarboxylates such as. B. etherified or esterified polycarboxylates, especially polycarboxylate ethers (PCE). The dispersant serves to stabilize the constituents of the composition and prevents agglomeration of the precipitating polymers in the subsequent crosslinking reaction in process step (b). It is also possible to add very finely divided solids such as nanocrystalline cellulose or nanoparticulate barium sulfate as an agglomeration inhibitor. The dispersant or spacer is usually used in a concentration in the range from 0.01% by weight to 3% by weight, for example in the range from 1% by weight to 2% by weight, based on the reaction mixture. Surprisingly, it has been found that, for. B. Polycarboxylate ether is sufficient in a smaller amount than, for. B. polyvinyl pyrrolidone.

The cross-linking of the precondensate obtained in process step (a) with the aid of ammonia to form a cross-linked polymer, provided in step (b), takes place in such a way that the precondensate on the one hand (precondensate flow) and ammonia on the other hand (ammonia flow) are provided as liquid media and sprayed onto the collision point (Fig. 1). In the case of the precondensate, the liquid medium is preferably an aqueous solution of the precondensate. If appropriate, a suspension or a colloid can also be present. The preferred solvent used for ammonia is water. The content of precondensate in the precondensate stream in process step (b) can vary over wide ranges and is generally 5% by weight to 50% by weight, preferably 8% by weight to 30% by weight, particularly preferably 9% by weight. % to 20 wt. -% based on the total mass of the aqueous solution. The ratio of ammonia flow: precondensate flow is controlled in such a way that ammonia in a molar ratio to the tetrakishydroxymethylphosphonium compound in the range of (1.0 to 4.0): 1, preferably in the range of (1.2 to 3.5): 1, is particularly preferably metered in the range from (2 to 2.5): 1. According to a preferred embodiment of the invention, ammonia is dosed in such a way that the dispersion obtained has a pH in the range from 7 to 10, preferably in the range from 8 to 9, at the outlet. is particularly preferably dosed in the range of (2 to 2.5): 1. According to a preferred embodiment of the invention, ammonia is dosed in such a way that the dispersion obtained has a pH in the range from 7 to 10, preferably in the range from 8 to 9, at the outlet. is particularly preferably dosed in the range of (2 to 2.5): 1. According to a preferred embodiment of the invention, ammonia is dosed in such a way that the dispersion obtained has a pH in the range from 7 to 10, preferably in the range from 8 to 9, at the outlet.

For example, the precondensate and the ammonia in step (b) can be injected into the reactor chamber under a pressure of 10 bar or more, for example more than 50 bar, but in any case not more than 4,000 bar.

Step (c) can either take place in the reaction space from step (b) or in a separate reactor space.

It is preferably provided that the crosslinked polymer obtained in step (b) is oxidized outside the reaction space of step (b). For example, the reaction can take place in a conventional reactor with the aid of an oxidizing agent.

In selected cases, as described above, the oxidation can take place in the reaction space of step (b). It could be provided here, for example, that the oxidation is combined with the cross-linking step by introducing, for example, 0 3 (ozone) or 0 2 via the gas flow, which is pressed into the reactor space onto the collision point.

The oxidation in process step (c) can be carried out using the customary oxidizing agents such as hydrogen peroxide, ammonium peroxodisulfate, oxygen, air (oxygen) or perchloric acid. The molar ratio between the precursor of the flame retardant and the oxidizing agent is generally about 1: 1 to 1: 1, 2.

Furthermore, a process step (d) can be provided, according to which soluble reaction products are separated off after the oxidation in step (c). In this way, the flame retardant can be separated from dissolved impurities by means of the permeate stream and concentrated by means of the retentate stream by means of methods known to the person skilled in the art, for example by means of filtration, preferably by means of tangential flow filtration (cross-flow filtration) or diafiltration (FIG. 2).

According to one embodiment, an acid can additionally be used in process step (d) in order to remove undesired by-products such as oligomers and basic compounds even more selectively. The acid used is generally selected from the group HCl, H2SO4, H3PO4 and acetic acid. The acid is generally diluted in a concentration of about 1 to 75%, preferably in a concentration of about 1 to 20%, particularly preferably in a concentration of about 1 to 9% in a solvent selected from the group consisting of water, methanol, ethanol or other solvents known to the person skilled in the art, or a mixture of these, are used. The preferred solvent used to dilute the acid is water. The amount of acid that is used to purify the flame retardant obtained in process step (c), can vary over a wide range. In general, one volume fraction of flame retardant is one volume fraction of acid

used, according to a preferred embodiment, a double volume fraction, according to a particularly preferred embodiment, three times the volume of acid is used.

The flame retardant obtained in process step (d) can subsequently be washed one or more times with a solvent, single to double the volume of solvent being used for washing, based on the volume of the flame retardant, in order to wash acid-free. This is done by adding a solvent to the flame retardant obtained after process step (d) and then performing a tangential flow filtration (cross-flow filtration) or diafiltration. Water is preferably used for washing. If necessary, washing is carried out at the beginning with water to pH 7 and at the end with N-methylmorpholine-N-oxide.

If necessary, before the exchange of water for N-methylmorpholine-N-oxide, a step for thickening can be carried out, which is carried out by mechanical processes known to the person skilled in the art (eg centrifugation) or thermal processes (eg evaporation).

The concentrated flame retardant is then incorporated into fibers or fiber materials, for example as part of the lyocell process or viscose process or cupro process or by processes in which ionic liquids are used as a dissolving medium for the cellulose.

Therefore, the invention also relates to a method for producing flame-retardant cellulosic man-made fibers from a spinning mass, comprising the provision of a polymer from a tetrakishydroxyalkylphosphonium compound prepared according to the aforementioned type and mixing with a cellulosic-based spinning mass, the polymer being made from a tetrakishydroxyalkylphosphonium compound in In the form of an aqueous dispersion in an amount of 5% by weight to 50% by weight based on the cellulose,

Spinning the spinning mass through a spinneret into a spinning bath to form filaments,

- hiding the filaments,

- Failure of the filaments and

- Post-treatment with washing, bleaching and finishing.

The filaments can be endless multifilaments or staple fibers. In the case of staple fibers, after the filaments have precipitated, a step of cutting the filaments into staple fibers is provided.

One aspect of the invention further relates to cellulosic man-made products, comprising a flame retardant comprising an oxidized polymer from a tetrakishydroxyalkylphosphonium compound with at least one nitrogen compound, comprising at least one NH 2 or at least two NH groups, or NH 3 with a particle size d 99 of <1 , 8, preferably <1, 7, particularly preferably <1 μm. Particle sizes d 99 to 0.9 μm are conceivable. It is preferably provided that it is a textile fiber with a fineness of> = 0.9 dtex to <= 3.

The cellulosic man-made product can, for example, be a film, powder, fleece or fibrid. The nonwovens can be, for example, meltblown nonwovens using the Lyocell or Cupro process.

The inventors have found that, according to the invention, a particle size d 99 of <1.8, preferably <1.7, particularly preferably <1 μm can be achieved with the method described above. In the wet milling process, such particle sizes cannot be achieved at commercially acceptable costs; the limit is d 99 of 2 μm or more.

The dope is preferably a solution of cellulose in an aqueous tertiary amine oxide.

DETAILED DESCRIPTION OF THE INVENTION

In Scheme I below, an example of the synthesis of the oxidized polymer from a tetrakishydroxyalkylphosphonium compound with urea is shown. It is known to the person skilled in the art that this is only one of several stoichiometrically possible compositions of the final, crosslinked precondensate.

+ 2CI
THP-chtortd urea precondensate

Precondensate cross-links it precondensate

In the first step, tetrakishydroxymethylphosphonium chloride is reacted with urea in step (a) to form a precondensate. Step (b) is then carried out in a microjet reactor by converting the precondensate to a crosslinked polymer using ammonia. In this case, ammonia and the precondensate are each sprayed separately from one another by means of a nozzle in aqueous solution into a reactor space enclosed by a reactor housing at a common collision point. In one embodiment variant, a cooling gas is introduced into the reactor space through an opening to maintain the gas atmosphere inside the reactor. The resulting products and excess gas are removed from the reactor housing through a further opening by overpressure on the gas inlet side or by negative pressure on the gas outlet side. The alternative embodiment variant provides that no cooling gas is introduced into the reactor space and the resulting products are removed from the reactor housing through an opening by negative pressure on the gas outlet side.

According to a preferred embodiment, step (c) takes place outside the microjet reactor, with H2O2 being added to the oxidized polymer as an oxidizing agent.

Fig. 1 shows schematically step (b) of the process in a reactor.

Fig. 2 schematically shows step (d) of the method.

1 shows a reactor housing with a reactor space, the precondensate R1 from step (a) being introduced into the reactor space from the side. Ammonia R2 is also introduced into the reactor space, with the precondensate R1 and the ammonia R2 forming

hit a collision point. To discharge the reaction products, a gas can be introduced via an opening 1, which emerges on the gas outlet side 2 with the reaction product. It has also been shown that the precondensate R1 and the ammonia R2 are brought to a collision point without a carrier gas being introduced via the opening 1. In such an embodiment, the reactor housing can be operated with a reactor space and a closed opening 1 for gas. The reaction product can then be removed by means of negative pressure via the gas outlet side 2.

2 shows the purification step (d), the reaction product from step (c) initially being introduced into a storage container 12 as feed 11. This is cleaned by the pump 16 via a membrane 14, for example via tangential flow filtration. The retentate 13 is fed back into the storage container 12. The permeate 15 is derived.

Example 1: Production of a flame retardant dispersion by using a microjet reactor (MJR) and subsequent spinning out of flame retardant fibers according to the viscose process:

The precondensate is produced analogously to AT 510 909 A1, with tetrakishydroxymethylphosphonium chloride (THPC) instead of tetrakishydroxymethylphosphonium sulfate being used as the starting component for the reaction with urea.

The cross-linking of the obtained precondensate with ammonia is then carried out in a microjet reactor. For this purpose, the precondensate obtained is metered as a 10% by weight solution, after adding 12% by weight of polyvinylpyrrolidone (Duralkan INK 30) based on the precondensate, as a precondensate stream continuously to position R1 of the MJR at a pressure of 11 bar. A 1.5% by weight ammonia solution at position R2 is continuously metered in as an ammonia stream at a pressure of 11 bar. The reaction product emerging at the product or gas outlet side 2 is collected with H 2 O 2added and stirred for 30 min at a temperature not higher than 40 ° C., the molar ratio between the precursor of the flame retardant (precondensate) and the oxidizing agent being 1: 1. A suspension with a solids content of oxidized, crosslinked precondensate of 4.9% is obtained. The particle size d 99 is 1.79 μm.

The oxidized, cross-linked precondensate is then purified and concentrated by tangential flow filtration (FIG. 2). For this purpose, 12.3 kg of suspension are filled into the storage container and processed over a polyethersulfone membrane (150 kDa and 0.6 m 2 filter area) at a pressure of 2 bar over 4 cycles. After cycles 1 to 3, the mixture is diluted with deionized water so that the initial weight in the storage container is 12.3 kg. After 4 cycles over a total duration of 2.5 h, 4.3 kg of suspension with a solids content of 14.7% are obtained.

The suspension produced is particularly suitable for the production of flame-retardant cellulosic moldings.

Der Anteil des Flammschutzmittels in der cellulosischen Man-made-Faser, in Form einer Viskose- oder Lyocell-Faser, kann zwischen 5 Gew.-% und 50 Gew.-%, bevorzugt zwischen 10 Gew.-% und 30 Gew.-%, besonders bevorzugt zwischen 15 Gew.-% und 25 Gew.-% bezogen auf die Faser liegen. Bei zu geringem Anteil ist der flammhemmende Effekt unzureichend, bei über der empfohlenen Grenze liegenden Anteilen verschlechtern sich übermäßig die mechanischen Eigenschaften der Faser. Mit diesen Anteilen kann eine flammhemmende cellulosische Man-made-Faser erhalten werden, die dadurch gekennzeichnet ist, dass die Festigkeit im konditionierten Zustand von 18 cN/tex bis 50 cN/tex beträgt.

A beech pulp (R18 = 97.5%) was used to produce a viscose with the composition 6.0% cellulose / 6.5% NaOH using 40% CS2. A modifier (2% dimethylamine and 1% polyethylene glycol 2000, each based on cellulose) and 22% based on cellulose of the flame retardant in the form of the 14.7% dispersion were added to the viscose with a spinning gamma value of 62 and a viscosity of 120 falling ball seconds. The mixed viscosity was spun with 60 μm nozzles into a spinning bath of the composition 72 g / l sulfuric acid, 120 g / l sodium sulfate and 60 g / l zinc sulfate at a temperature of 38 ° C., in a second bath (water at 95 ° C.) to 120 % stretched, and drawn off at 42 m / min. The aftertreatment (hot diluted H 2S04 / water / desulphurisation / water / bleach / water / finishing) was carried out according to known methods. A fiber was obtained with a titer of 2.19 dtex, a strength (conditioned) of 21.2 cN / tex and a maximum tensile elongation (conditioned) of 12.4%.

Example 2: Production of a flame retardant dispersion by using a microjet reactor (MJR) and subsequent spinning of flame retardant fibers according to the Lyocell process:

The precondensate is produced analogously to AT 510 909 A1, with tetrakishydroxymethylphosphonium chloride (THPC) instead

Tetrakishydroxymethylphosphoniumsulfat is used as a starting component for the reaction with urea.

The cross-linking of the obtained precondensate with ammonia is then carried out in a microjet reactor. For this purpose, the precondensate obtained as a 10 wt .-% solution, after adding 5 wt .-% of an esterified polycarboxylate (Viscocrete P-510) based on precondensate, as a precondensate stream continuously at position R1 of the MJR with a pressure of 1 1 bar dosed. A 1.5% by weight ammonia solution at position R2 is continuously metered in as an ammonia stream at a pressure of 11 bar. The reaction product emerging at the product or gas outlet side 2 is collected with H 2 O 2added and stirred for 30 min at a temperature not higher than 40 ° C., the molar ratio between the precursor of the flame retardant (precondensate) and the oxidizing agent being 1: 1. A suspension with a solids content of oxidized, cross-linked precondensate of 5.3% is obtained. The particle size d 99 is 1.71 μm.

The oxidized, cross-linked precondensate is then purified and concentrated by tangential flow filtration (FIG. 2). For this purpose, 12.3 kg of suspension are filled into the storage container and processed over a polyethersulfone membrane (150 kDa and 0.6 m 2 filter area) at a pressure of 2 bar over 4 cycles. After cycles 1 to 3, the mixture is diluted with deionized water so that the initial weight in the storage container is 12.3 kg. After 4 cycles over a total time of 2.5 hours, 4.3 kg of suspension with a solids content of 16% are obtained.

The suspension produced is particularly suitable for the production of flame-retardant cellulosic moldings.

The proportion of the flame retardant in the cellulosic man-made fiber, in the form of a viscose or lyocell fiber, can be between 5% by weight and 50% by weight, preferably between 10% by weight and 30% by weight , particularly preferably between 15 wt .-% and 25 wt .-% based on the fiber. If the proportion is too low, the flame-retardant effect is insufficient; if the proportion is above the recommended limit, the mechanical properties of the fiber deteriorate excessively. With these proportions, a flame-retardant cellulosic man-made fiber can be obtained which is characterized in that the strength in the conditioned state is from 18 cN / tex to 50 cN / tex.

22%, based on cellulose, of the flame retardant in the form of the 16% dispersion were added to the slurry (mixture of pulp / aqueous NMMO) and water was evaporated to produce a fiber-free spinning solution with the composition 12% cellulose / 77% NMMO / 11% water. A sulphate high alpha pulp was used as the pulp.

The spinning mass was spun according to the known wet-dry spinning process at a spinning temperature of 110 ° C. with the aid of a 100 μm nozzle in a spinning bath containing 25% NMMO at a temperature of 20 ° C. to give 2.2 dtex fibers. Fibers with a strength (conditioned) of 35.0 cN / tex and a maximum
tensile elongation (conditioned) of 13.3% were obtained.
EXPECTATIONS

1 . A method for producing an oxidized polymer from a tetrakishydroxyalkylphosphonium compound with NH 3 or at least one nitrogen compound comprising at least one NH 2 or at least two NH groups, or NH 3 comprising the steps

(a) Reacting at least one tetrakishydroxyalkylphosphonium compound with NH 3 or at least one nitrogen compound in order to obtain a precondensate, the molar ratio of the tetrakishydroxyalkylphosphonium compound to the nitrogen compound in the range from 1: (0.05 to 2.0), preferably in the range from 1 : (0.5 to 1, 5), particularly preferably in the range of 1: (0.65 to 1, 2),

(b) Cross-linking of the precondensate obtained in process step (a) with the aid of ammonia to form a cross-linked polymer,

(c) Oxidation of the crosslinked polymer obtained in step (b) by adding an oxidizing agent to the oxidized polymer, characterized in that

in step (b) the precondensate from step (a) and the ammonia are each sprayed by means of a nozzle into a reactor space enclosed by a reactor housing at a common collision point.

2. The method according to claim 1, characterized in that in step (b) the precondensate from step (a) and the ammonia are each injected by means of a nozzle into a reactor space enclosed by a reactor housing at a common collision point, the resulting products through a Opening (2) can be removed from the reactor housing by negative pressure on the product and gas outlet side.

3. The method according to claim 1, characterized in that in step (b) the precondensate from step (a) and the ammonia are each injected by means of a nozzle into a reactor space enclosed by a reactor housing at a common collision point, with an opening (1 ) a gas, an evaporating liquid, a cooling liquid or a cooling gas is introduced into the reactor space to maintain the gas atmosphere inside the reactor, in particular at the collision point of the liquid jets, or to cool the resulting products, the resulting products and excess gas being fed through a further opening (2) are removed from the reactor housing by overpressure on the gas inlet side.

4. The method according to any one of claims 1 to 3, characterized in that the nitrogen compound is selected from the group consisting of urea, thiourea, biuret, melamine, ethylene urea, guanidine and dicyandiamide.

5. The method according to any one of claims 1 to 4, characterized in that in step (b) the precondensate on the one hand and ammonia on the other hand are provided as liquid media and sprayed onto the collision point.

6. The method according to claim 5, characterized in that the liquid medium in the case of the precondensate is an aqueous solution and that the liquid medium in the case of

Ammonia is an aqueous solution.

7. The method according to any one of claims 1 to 6, characterized in that after the oxidation according to step (c) soluble reaction products are separated off, preferably by means of tangential flow filtration.

8. The method according to any one of claims 1 to 7, characterized in that the alkyl radical of the tetrakishydroxyalkylphosphonium compound is selected from the group consisting of methyl, ethyl, propyl or butyl.

9. A method for making flame retardant cellulosic man-made products from a spinning mass, comprising

the provision of a polymer from a

Tetrakishydroxyalkylphosphonium compound produced according to one of claims 1 to 8, mixing with a spinning mass based on cellulose,

wherein the polymer comprises a tetrakishydroxyalkylphosphonium compound in the form of an aqueous dispersion in an amount of 5% by weight to 50% by weight based on the cellulose,

and spinning the dope through a spinneret into a spinning bath.

10. The method according to claim 9, characterized in that the man-made products are man-made fibers, filaments being formed during the spinning of the spinning mass through a spinneret in a spinning bath, the filaments then being drawn and precipitated, with subsequently after-treatment with washing, bleaching, and finishing is provided.

1 1. A method according to claim 9 or claim 10, characterized in that the dope is a solution of cellulose in an aqueous tertiary amine oxide.

12. The method according to claim 9 or claim 10, characterized in that the spinning mass is a solution of cellulose in the form of a cellulose xanthate.

13. The method according to claim 9 or claim 10, characterized in that the spinning mass is an ammoniacal solution of cellulose in tetraammine copper (II) hydroxide.

14. The method according to claim 9 or claim 10, characterized in that the spinning mass is a solution of cellulose in an ionic liquid.

15. Cellulosic man-made product, containing a flame retardant comprising an oxidized polymer of a tetrakishydroxyalkylphosphonium compound with at least one nitrogen compound, comprising at least one NH 2 or at least two NH groups or NH 3 , with a particle size d 99 of <1.8, preferably <1.7, particularly preferably <1 μm.

16. Cellulosic man-made product according to claim 15, characterized in that it is a textile fiber with a fineness of> = 0.9 dtex to <= 3 dtex.

17. Cellulosic man-made product according to claim 15 or claim 16, characterized in that the proportion of flame retardant is between 5% by weight and 50% by weight, preferably between 10% by weight and 30% by weight, particularly preferably between 15% by weight and 25% by weight.

18. Cellulosic man-made product according to one of claims 15 to 17, characterized in that the strength is from 18 cN / tex to 50 cN / tex.

19. Cellulosic man-made product according to one of claims 15 to 18, characterized in that it is a film, powder, fleece or fibrid.