NL1004957C2 - Method for preparing low-fibrillating cellulose fibers. - Google Patents

Description

PROCESS FOR PREPARING LITTLE FIBRILLING CELLULOSE FIBERS

The invention relates to a method for preparing low-fibrillating cellulose fibers from a solution containing cellulose and / or cellulose derivatives.

Such a method is known from various patent publications for making Lyocell fibers, such as WO 95/30043, WO 96/0777, WO 96/0779 and EP 691426. In the so-called Lyocell process, cellulose is dissolved in an organic solvent (eg N methylmorpholine N-oxide) and subsequently spun using an air-gap spinning process and coagulated in a suitable coagulant. Without additional measures, the fibers obtained exhibit a high degree of fibrillation, especially when these fibers are exposed to a mechanical load when wet. In the aforementioned patent publications, various measures are mentioned to counter this fibrillation, such as adding additives to the coagulant, the use of specific gases in the air gap or after-treatment of the obtained fibers with certain chemicals, for example with a cross-linking agent (“ crosslinking agent ”). The main drawback of such methods is that this means that one or more additional steps must be included in the entire process run for treating the fibers and / or recovering the additional added chemicals for environmentally friendly processing.

Such a method is also known for making cellulose fibers from a solution containing cellulose derivatives. For example, cellulose fibers made by the viscose process exhibit little or no fibrillation when exposed to mechanical stress when wet. The viscose process contains a number of successive steps, for example 1004957 2 for making the spinning solution, and is not environmentally friendly without additional measures.

From WO 95/20629 a method is known for making cellulose fibers with low fibrillation by spinning a solution of cellulose formate. In this method, a number of different chemicals are used to make the solution and as a coagulant, which is disadvantageous in an economical and environmentally friendly process operation. The fibers are obtained by placing the extruded solution in a gel phase followed by the coagulation of the extrudates.

The invention relates to a simple method for making low-fibrillating cellulose fibers, wherein it is not necessary to add or apply additional chemicals before, during, or after the spinning process, by spinning a solution containing cellulose and / or cellulose derivatives using a centrifugal spinning machine, the formed cellulose fibers are dried at low tension.

In this patent application, cellulose fibers are intended to mean both continuous filaments, fibers of short length (less than 100 mm, i.e. stack of fibers), as well as fibers of longer length (> 100 mm). The fibers can be bundled into a yarn, a sliver, a skein, or processed into a fabric or a non-woven.

In this patent application, fibrillation is understood to mean breaking, tearing or tearing apart fibrils in the longitudinal direction of the fiber as a result of mechanical stress. Such fibrillation gives the fibers a hairy or felted appearance.

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In this application, a centrifugal spinning machine is understood to mean a device comprising a centrifuge surrounded by a jacket, wherein one or more spinning holes are distributed more or less regularly over the outer circumference of the centrifuge. Due to the rotation of the centrifuge, the solution, which is supplied (under pressure) to the centrifuge via a supply line, is extruded through the spinning holes in the direction of a jacket. Depending on the spin speed of the centrifuge, the solution is dispensed after extrusion. On contact with a liquid flowing along the jacket, coagulation of the (stretched) solution occurs and cellulose fibers are formed. The degree of stretching can be adjusted, inter alia, by means of the diameter of the spin holes, the rotation speed of the centrifuge and the distance between the outer circumference of the centrifuge and the inner side of the jacket. In order to obtain a good stretching of the filaments, the radius of the inside of the jacket is preferably at least 10% larger than the radius of the outer circumference of the centrifuge, in particular at least 25% larger, more in particular at least 35% taller. The maximum degree of stretching depends, inter alia, on the DP of cellulose or the cellulose derivative and the concentration of cellulose or cellulose derivative in the solution. If the maximum degree of stretching is exceeded, the filaments break in the space between the centrifuge and the coagulation liquid.

It is not necessary for only the centrifuge to rotate for the centrifuge to work properly. It is also possible that the jacket along which the coagulation liquid moves rotates. The jacket can rotate in the same direction as well as in the opposite direction to the centrifuge.

In a favorable method, the axis of rotation of the centrifuge is placed more or less vertically and the coagulation liquid flows down the jacket, whereby the fibers / filaments formed with the coagulation liquid 1004957 4 flow out of the jacket and can be collected and collected. merged into a fuse. The number of fibers and the length of the fibers play an important role in the formation of such a wick. With sufficient cohesion in the wick, it can be spun in a continuous process and further processed, for example by neutralizing, washing, carrying, surfacing, cutting and / or frizz.

The method according to the invention preferably uses a centrifugal spinning machine as described in international patent application WO 96/27700.

An important role in such a centrifugal spinning process according to the invention is played by the diameter of the spinning holes. The larger this diameter, the smaller the chance of clogging by impurities or undissolved particles in the solution. Preferably, spin holes with a diameter greater than 100 µm are used, more in particular with a diameter between 120 and 500 µm. The use of large diameter spinning holes also has the advantage that the pressure in the spinning machine will not become too high.

20

An important advantage of a centrifugal spinning process over other known spinning processes, for example spinning processes for making staple fiber or continuous filament yarn, is found in the ability to process a large amount of spinning solution per unit time. Furthermore, it is possible to extend the extruded spinning solution further, without a large decrease in the final mechanical properties of the fibers obtained, than in the above known spinning processes.

1004957 »5

It has been found that if the viscosity of the spinning solution is chosen too high, disturbances can occur during the spinning process which lead to frequent breakage of the fibers during stretching and / or coagulation or which can give rise to large differences in, for example, the cross section of the fibers formed. Fluctuations can occur both in the longitudinal and transverse directions of the fibers. Large differences in the cross-section of the formed fibers are less desirable in view of the textile application of the fibers. The viscosity of the solution can be influenced in a manner known to the person skilled in the art, for example, by changing the cellulose concentration in the solution.

A too low viscosity of the spinning solution is also less desirable since it is then not possible to make cellulose fibers.

The method according to the invention uses solutions containing cellulose and / or cellulose derivatives. Solutions can be used in which cellulose is dissolved in an organic solvent, a mixture of organic solvents, an inorganic solvent, a mixture of inorganic solvents, or in a mixture of organic and inorganic solvents.

20

Furthermore, solutions of cellulose derivatives can be used in which a cellulose derivative or a mixture of cellulose derivatives is dissolved in an organic solvent, a mixture of organic solvents, an inorganic solvent, a mixture of inorganic solvents, or in a mixture of organic and inorganic solvents.

Optically isotropic and optically anisotropic solutions can be used in the method of the invention. To the solvent or to the solution, substances can optionally be added which facilitate the dissolution of cellulose and / or cellulose derivatives or which improve the processability of the solution, or auxiliaries (additives) for example for degradation of cellulose and / or cellulose derivatives as much as possible, or dyes and the like.

Examples of suitable solutions are for example: • a solution of cellulose in - a tertiary amine oxide, for example a solution of cellulose in N-methylmorpholine N-oxide as described in US 4,246,221, - a mixture of phosphoric acid and / or anhydrides thereof and water as described in WO 96/06208 (anisotropic solution) or in the non-prepublished patent application NL 1002236 in the name of the applicant (isotropic solution), - a mixture of phosphoric or polyphosphoric acid, sulfuric acid and water, as described in Japanese patent application JP 4258648 , 15 - a mixture containing dimethyl acetamide and lithium chloride, - a mixture containing copper sulfate and ammonium hydroxide, - a mixture containing trifluoroacetic acid and dichloromethane, - a mixture containing ammonia and ammonium thiocyanate, 20 · a solution of cellulose acetate in - trifluoroacetic acid, or a mixture containing trifluoroacetic acid acetone or a mixture containing acetone, - phosphoric acid or a mixture containing phosphoric acid, 25 · a solution of cellulose carbamate in caustic soda u • a solution of cellulose formate in - phosphoric acid or a mixture containing phosphoric acid, for example a mixture of phosphoric acid and formic acid, 1004957 »7 - dimethylsulfoxide or a mixture containing dimethylsulfoxide, for example a mixture of dimethyl sulfoxide and water, a mixture of a dimethyl sulfoxide and ethylene glycol, or a mixture of dimethyl sulfoxide, ethylene glycol, and water, 5-N-methyl-2-pyrrolidone or a mixture containing N-methyl-2-pyrrolidone, e.g. a mixture of N-methyl-2-pyrrolidone and water,

However, other solutions containing cellulose and / or cellulose derivatives can also be used in the method according to the invention.

10

If a solution containing cellulose derivatives is used, the fibers obtained by spinning the solution using a centrifugal spinning machine must be regenerated in a separate step to obtain little fibrillating cellulose fibers. Regeneration can take place, for example, by saponification, for example with a lye solution, or by a high temperature steam treatment.

For the coagulation of the spinning solution, all known coagulants for solutions containing cellulose and / or cellulose derivatives can be used. For example, an organic solvent (for example, acetone, methanol, or ethanol), a mixture of organic solvents, an inorganic solvent, a mixture of inorganic solvents, a mixture of organic and inorganic solvents, or a mixture of organic and / or inorganic solvents with water can be used as a coagulant. It is advantageous to use water as a coagulant, especially when cations have been added to the water, more particularly when monovalent cations have been added to the water, such as Na +, K +, or NH4 +.

30 1004957 8

It has been found that if a solution containing cellulose and / or cellulose derivatives is spun using a centrifugal spinning machine, few fibrillating cellulose fibers are obtained if the fibers are dried under low tension. Low tension is here understood to mean a tension lower than 2 cN / tex (based on the titer of the dried fibers). Preferably, the fibers are dried under a tension below 1 cN / tex, more particularly at the lowest possible tension. In a particularly favorable method, the fibers are dried stress-free. It has been found that the fibers shrink 5-10 20% during drying if they are dried under the lowest possible tension or without tension.

Many ways are known for drying fibers under low tension or without tension. For example, it is possible to dry the fibers on a porous belt, for example with the help of heated air. It is also possible to dry the fibers on a shrink sleeve.

It has further been found that it is furthermore advantageous to obtain low-fibrillating fibers to subject the fibers in the wet state as little as possible to a mechanical load, in particular to a longitudinal mechanical load, before the final drying step in the process. of the fibers.

In the method according to the invention cellulose fibers are obtained which show little fibrillation, in particular when these fibers are exposed to a mechanical load in the wet state. The degree of fibrillation can be measured using the so-called fibrillation test (“Schütteltest”), in which very fibrillating fibers in this test are rated 6 and a few to no fibrillation fibers are rated 0 or 1. The fibers obtained according to the Method 1004957 of the present invention is rated <3, especially <2, more particularly <1, in the fibrillation test.

It has further been found that the fibers obtained according to the method of the present invention exhibit a special combination of properties which can be characterized as follows:

Elemental titer <10 dtex,

Crystalline orientation angle> 20 ° and Elongation at break <30%.

10

In general, in the known spinning processes for making cellulose fibers, it has been found that a low molecular orientation (i.e. a high crystalline angle of orientation) can only be achieved if the fibers are little stretched. Due to this low degree of stretching, such fibers have a high elemental titer and a high elongation at break.

The low-fibrillating fibers according to the invention preferably have the following combination of properties, which make these fibers particularly suitable for textile application: - Elemental titre: from 0.5 to 5 dtex, preferably 0.5 to 3 dtex, - Crystalline orientation angle:> 20 °, preferably> 30 °, more preferably> 40 ° - Elongation at break: <30%, preferably between 5 and 20%.

A low elemental titer of the fibers is important for the final properties of the fibers in a fabric, such as, for example, gloss and grip. A low molecular orientation (i.e. a high crystalline angle of orientation) appears to be important for the fibrillation properties of the fibers. The elongation at break is important with regard to the processing of the fibers for their textile application.

1004957 10

The fibers thus obtained can be further processed for textile applications, for example by cutting the formed wick into short-length fibers (staple fibers). These staple fibers can be made suitable for textile application by means of textile techniques known to the skilled person (including carding, ring spinning).

Partly because of the low fibrillation, these fibers are particularly suitable for textile applications. These fibers are also particularly suitable for textile applications due to other properties. For example, the dyeability of these fibers is better than the dyeability of cotton or cellulose fibers obtained by the viscose process. The dyeability of the fibers can be measured in a standardized dyeing test using a blue dye (Solophenyl-Bleu). In this test, the low-fibrillating fibers of the present invention exhibit a bath exhaustion between 70 and 100%. For known cellulose products, a bath exhaustion of less than 60% is found in this test.

Fabrics made using these fibers have a particularly beautiful shine and a good grip.

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Measurement methods

Paintability

The dyeability of the fibers has been measured after drying in vacuum at 50 ° C for 10-16 hours. 1 gram of the fiber is then placed in 200 ml of water at a temperature of 85 ° C to which 1 wt.% Solophenyl Bleu GL 250% and 2 g Glauber salt (Na2SO4 * 10H2O) have been added. During the measurement (45 minutes), the temperature of the water is kept at 85 ° C. The absorbance of the solution at 490 nm is determined spectrophotometrically before adding the fibers and after the measurement. The bath exhaustion (in% abs.) Is then calculated as the difference in absorbance before addition of the fibers and at the end of the measurement. A bath exhaustion of 100% therefore means that all dye has been absorbed by the fibers. Mechanical properties

The mechanical properties of the fibers have been determined according to ASTM standard D2256-90, using the following settings.

The fibers were clamped using Arnitel® clamping pads of 10x10 mm. The filaments were conditioned for 24 hours at 21 ° C and 65% relative humidity. The clamping length was 20 mm, and the filaments were stretched at a constant elongation of 20 mm / min.

The filament titer or elemental titer, expressed in dtex, is calculated on the basis of the functional resonance frequency (ASTM D 1577-66, part 25, 1968).

The breaking strength, strength and elongation at break were obtained from the force-elongation curve and the measured filament titer.

The mean value of 20 individual determinations was taken for each given measured value.

30 1004957 12

Fibrillation

The fibrillation of the cellulose fibers can be measured using a so-called "Schütteltest". In this test, 7 mg of fiber material is placed in a 20 ml beaker. 10 ml of water is added to the fiber material and the whole is left in a quiet place at room temperature for 30 minutes. The beaker with contents is then shaken vigorously for 2 hours. After this, the fibrillation with a microscope is visually assessed, whereby a strongly fibrillated fiber is assessed with the number 6 and no or very few fibrillated fibers are assessed with the number 0 or 1. Depending on the degree of fibrillation, the fiber material in the tests a rating from 0 to 6.

Examples 15

The invention is further elucidated by means of a few examples. However, the invention is not limited to these examples.

20 Example 1

A slurry containing about 4 wt.% Cellulose (80 wt.% Viskokraft ELV, DP = 650, and 20 wt.% Viskokraft VHV, DP = 1650) and 96 wt.% Of an aqueous N-methylmorpholine N-oxide (NMMO solution with a water content of about 20 wt% was continuously fed to a twin screw extruder equipped with a water extraction device from the slurry.

By extracting part of the water, a solution was obtained in this way containing 4% by weight of cellulose, 16% by weight of water and about 80% by weight of NMMO. The solution also contained <0.2% by weight of stabilizer 30 (propyl gallate).

1004957 13

This solution was spun using a centrifugal spinning machine as described in the applicant's international patent application WO 96/27700, wherein the centrifuge with an outer diameter of 30 cm was provided with 12 spinning holes with a diameter of 250 µm each. At different temperatures, a mass flow rate of 5.9 kg of solution per hour and at a variable spin speed, the solution was extruded through the spinning holes. The fibers formed were coagulated using 15 ° C water flowing down a jacket. The inner diameter of the jacket was also varied during the 10 experiments.

The fiber ion thus formed was collected, washed under low tension and dried after drying with Leomin for 10-16 hours at 50 ° C in vacuo under vacuum.

Table 1 gives some properties of the fibers thus obtained.

Table 1

Rrotor ^ shroud Tjpjp Titer I BT I EaB I Gfibr (rpm) (mm) __ (X) __ (dtex) __ (mN / tex) __ (%) __ 1500 500 100 1.8 ± 12% 170 ± 24% 13.1 ± 22 % 1 2000 500 100 1.6 ± 8% 110 ± 26% 10.9 ± 39% 2 3000 500 100 1.0 ± 9% 200 ± 29% 10.4 ± 22% 1-2 4000 500 100 0.8 ± 19% 140 ± 34% 7.5 ± 25 % 2 1500 500 80 1.2 ± 16% 130 ± 29% 7.9 ± 28% 2 1500 500 120 1.2 ± 13% 130 ± 32% 13.4 ± 34% 1-2 1500 600 100 1.6 ± 15% 160 ± 34% 17.6 ± 26 % 1-2 2000 600 100 1.1 ± 19% 210 ± 28% 11.4 ± 19% 1-2 3000 600 100 0.8 ± 23% 150 ± 26% 14.3 ± 55% 1 where Rrotor = spin speed of the centrifuge, Dmantei = inner diameter of 20 the jacket, Tspjn = spin temperature, BT = breaking strength, EaB = breaking elongation, Gfibr = fibrillation assessed.

25 1004957 14

Example 2

The solution obtained according to the method described in example 1 was spun using the same centrifugal spinning machine.

However, the centrifuge with an outer diameter of 30 cm was provided with 12 spin holes with a diameter of 150 µm each. At a spin temperature of 100 ° C and a spin speed of the centrifuge of 2000 rpm, different masses of the solution were spun per unit time. The fibers formed were coagulated using 15 ° C water flowing down a jacket (inner diameter 500 mm).

The fiber wick thus formed was collected, washed under low tension and dried after drying with Leomin for 10-16 hours at 50 ° C under vacuum under vacuum.

Table 2 gives some properties of the fibers thus obtained.

Table 2

Cap (Titer BT EaB Gfibr (kg / h) __ (dtex) __ (mN / tex) __ (%) __ 1.6 0.8 ± 57% 170 ± 41% 9.9 ± 46% 2.6 0.8 ± 9% 150 ± 24% 9.8 ± 40% 3.6 0.9 ± 16% 150 ± 28% 8.7 ± 23% 4.6 1.2 ± 8% 120 ± 21% 6.1 ± 34% 5.5 1.3 ± 10% 140 ± 31% 9.8 ± 37% where Dop, = throughput of the spinning solution, BT = breaking strength, 20 EaB = breaking elongation, Gfjbr = fibrillation assessed

Example 3

In the manner described in Example 1, a spinning solution was made containing 8% by weight of cellulose. In the manner described in Example 1, this solution was spun using a 1004957 centrifugal spinning machine, varying the temperature of the coagulation fluid.

Table 3 shows some properties of the fibers thus obtained.

5 Table 3 ^ rotor ^ jacket T $ pi 1 "coag Titer I BT I EaB I Gflbr (rpm) (mm) n (° C) (dtex) (mN / tex) (%)

(° C

___) ____ 3000 400 100 15 4.1 ± 26% 180 ± 33% 12.4 ± 51% 3000 400 120 15 ± ± ± 1500 500 120 35 4.1 ± 16 139 ± 21 24.2 ± 25 1 1500 500 120 40 3.6 ± 19 147 ± 14 9.5 ± 31 2 2000 500 100 15 ± ± ± 3 3000 500 100 15 2.3 ± 14% 280 ± 20% 10.7 ± 18% 3 3000 500 120 40 2.0 ± 17 139 ± 29 7.6 ± 25 2 4000 '500 100 15 1.0 ± 28% 270 ± 19% 11.7 ± 41% 2000 600 100 15 ± ± ± 3000 600 100 15 1.4 ± 18% 290 ± 17% 15.7 ± 30% where Rrot0r = spin speed of centrifuge, Dmantei = inner diameter of jacket, Tspin = spin temperature, T ^ g = temperature of coagulation liquid, BT = breaking strength, EaB = breaking elongation, Gfibr = fibrillation 10 rated *): Spin hole diameter 150 μηπ.

Example 4 Different solutions obtained according to the method described in example 1 were spun using the same centrifugal spinning machine.

However, the centrifuge with an outer diameter of 30 cm was provided with 12 spin holes with a diameter of 400 µm each. At a spin temperature of 120 ° C and a spin speed of the centrifuge of 3000 rpm, solutions containing 8, 10 and 12% by weight of cellulose were spun. The fibers formed were coagulated using 15 ° C water flowing down a jacket (inner diameter 500 mm).

1004957 16

The fiber wick thus formed was collected, washed under low tension and dried after drying with Leomin for 10-16 hours at 50 ° C under vacuum under vacuum.

Table 4 lists some properties of the fibers thus obtained.

5

Table 4

Coe, Titer BT EaB Gnbr (wt%) (dtex) (mN / tex) (%) 8 3.7 + 18% Ï7Ö ± 18% 12.4 ± 58% 2-3 10 4.6 ± 15% 220 ± 15% 13.7 ± 33% 2 12 5.7 ± 25% 230 ± 22% 12.1 ± 35% 2 where C ^ i = cellulose concentration in the solution, BT = breaking strength, EaB = breaking elongation, Gfibr = fibrillation rated 10

The dyeability of various samples obtained according to the above examples was measured. In Table 5 the measured bath exhaustion values for these fibers are given and compared with known cellulose fibers for textile use.

15

Table 5

Cellulose concentration in Spinning solution bath exhaustion (%) 4 84 8 100 8 100 10 84

Viscose fiber pile 51

Lyocell pile fiber 55

Cotton 44 1004957 17

Example 5

An anisotropic cellulose solution was prepared by dissolving 2688 g of cellulose powder (Buckeye V65, DP = 700) in a solvent, which solvent was obtained by mixing 19360 g of H3PO4 and 4840 g of PPA. Cellulose and the solvent were kneaded for 65 minutes and mixed at 16 ° C until a homogeneous anisotropic solution was obtained. The kneader was degassed for the last 45 minutes.

This solution was spun using a centrifugal spinning machine as described in applicant's international patent application 10 WO 96/27700, wherein the centrifuge with an outer diameter of 30 cm was provided with 24 spin holes with a diameter of 250 μπη each . At a temperature of about 45 ° C, a mass flow rate of 12 kg of solution per hour and at a centrifuge speed of 3500 rpm, the solution was extruded through the spinning holes. The fibers formed were coagulated using 15 ° C water flowing down a jacket. The jacket had an inner diameter of 50 cm.

The fiber wick thus formed was collected, washed with a 2% sodium bicarbonate solution until a pH = 7 was reached. Then, the wick was dried after drying with RT32A for 10-16 hours at 25 ° C.

The fibers in the wick had an average linear density of 3.3 dtex (± 40%), a breaking strength of 77 mN / tex, an elongation at break of 10% and a fibrillation rating = 1.

25

Comparative example 1

A solution containing 4% by weight of cellulose obtained by the method described in Example 1 was spun in a conventional wet spinning process through a spinneret with spin capillaries with a diameter of 250 1004957 18 μίτι, drawn in an air gap of 45 mm and coagulated in water. The filaments in the filament yarn thus obtained had a titer of 1.3 dtex (± 19%), a breaking strength of 270 mN / tex (± 7%), an elongation at break of 9.5% (± 9%), an initial modulus of 10.6 N / tex (± 4%) and a fibrillation 5 rated = 5-6.

Comparative example 2

Different solutions obtained according to the method described in example 1, with a cellulose concentration of 8 and 10%, were spun using a centrifugal spinning machine, in the manner as mentioned in example 1, whereby the formed fiber wick was treated with Leomin, a sleeve was wound and dried on the sleeve.

The fibers thus obtained had a fibrillation rating between 4 and 6.

15 1004957

Claims (16)

1. A method for making low-fibrillating cellulose fibers from a solution containing cellulose and / or cellulose derivatives, characterized in that the solution is spun using a centrifugal spinning machine and the fibers formed are dried under low tension. 2. A method according to claim 1, characterized in that the fibers formed are dried under a tension of less than 1 cN / tex. Method according to claim 2, characterized in that the formed fibers are dried under the lowest possible tension. Method according to claim 3, characterized in that the fibers are dried stress-free. A method according to any one of the preceding claims, characterized in that the solution is optically isotropic. 20 Process according to claim 5, characterized in that the solution contains cellulose and a tertiary amine oxide. 7. Process according to claim 6, characterized in that the solution contains cellulose and N-methylmorpholine N-oxide. A method according to any one of claims 1-4, characterized in that the solution is optically anisotropic. 1004957 Process according to claim 8, characterized in that the solution contains cellulose and / or a cellulose derivative and phosphoric acid. 10. Process according to claim 9, characterized in that the solution contains cellulose, phosphoric acid and / or anhydrides thereof and water. 11. Cellulose fiber characterized by the following combination of properties: - elemental titer <10 dtex, 10. crystalline orientation angle> 20 ° and - elongation at break <30%. Cellulose fiber according to claim 11, characterized in that the elemental titer of the fiber is 0.5 to 5 dtex. 15 Cellulose fiber according to claim 12, characterized in that the elemental titer of the fiber is 0.5 to 3 dtex. Cellulose fiber according to any one of claims 11-13, characterized in that the fiber has a crystalline orientation angle> 30 °. Cellulose fiber according to claim 14, characterized in that the fiber has a crystalline orientation angle> 40 °. Cellulose fiber according to any one of claims 11 to 15, characterized in that the fiber has an elongation to break between 5 and 20%. 1004957 COOPERATION TREATY (PCT) REPORT ON NEWNESS RESEARCH OF INTERNATIONAL TYPE IDENTIFICATION OF THE NATIONAL APPLICATION Characteristic of the applicant ol of the authorized representative ACR 2562 PDNL Dutch application no. an investigation of an international type Granted by the International Research Agency (ISA) to the application for an investigation of an international type No 13 January 1997 SN 28780 EN I. CLASSIFICATION OF THE SUBJECT MATTER (where different classifications are applied, all classification symbols specify) According to International Classification (IPC) Int. Cl. 6: 4/01/01/2/00 II. FIELD OF TECHNIQUE EXAMINED __Minimum Documentation Examined _Classification System__Classification Symbols Int. Cl.6 D 01 D, D 01 F Unauthorized documentation other than the minimum documentation to the extent that such documents have been included in the areas examined / ^ Hl- 1 I NO RESEARCH CAN BE DRAWN UPON CERTAIN CONCLUSIONS (remarks oo supplementation sheet) C "i" ~ <ï 1 LACK OF UNIT OF INVENTION (comments oo additionincsblsd) c ^ 'rn ΡΛ ""' (; ώ / 7ρΐί |) 0? ig? 9