KR20030061374A - Fibre and its production - Google Patents

Abstract

How to make lyocell fiber

(i) a trace of the cellulose in an aqueous tertiary amine N-oxide solvent, the solution having a glass transition temperature below the temperature at which the solution is formed, based on the weight of the cellulose dispersed therein; To 30% by weight;

(ii) extruding this solution through a mold into an aqueous coagulation bath to form lyocell fibers;

(iii) washing and drying the fibers to remove residual N-oxides;

(iv) crimping the fiber to introduce a crimp of 2.5 to 8 crimps / cm into the fiber.

In the process of the invention it is preferred that the thermoplastic polymer is uniformly dispersed in the fibers into domains, and that the substantial maximum size of all the domains does not exceed 50 nm.

The present invention also provides lyocell fibers comprising traces to 30% by weight of low melting thermoplastic polymer and having 2.5 to 8 crimps / cm.

Description

Fiber and its manufacturing method {FIBRE AND ITS PRODUCTION}

Lyocell fibers are prepared by dissolving cellulose in a third solvent, such as N-methylmorpholine N-oxide, in admixture with a suitable solvent. Preferred methods of making lyocell fibers are described in US Pat. No. 4,416,698. This method extrudes a cellulose solution in which solid cellulose is dissolved in an amine oxide solvent at room temperature through an air gap from a spinneret into a coagulation bath of water or dilute aqueous amine oxide solution and then removes the amine oxide solvent. And a method for producing cellulose fibers.

Japanese Patent Application Laid-Open No. 8-170224 discloses a disperse dye dyeable bicomponent fiber in the form of an island in the ocean, where the continuous "sea" component is a cellulose polymer spine from an organic solvent system and the "island" component is a dispersible dye. It consists of a polymer which can be dyed by the "island" component in this fiber having a size of 0.01-3 nm and comprised between 2-45% by weight based on the weight of the fiber.

British Patent 2121069 contains 15 to 60% by weight, in particular 40 to 50% by weight, based on fiber weight of barium sulfate, talc, muscobite or mixtures thereof as inorganic fillers, and optionally, polyethylene, polypropylene, polystyrene, Viscose rayon fibers for the production of nonwovens are described which comprise 1 to 60% by weight, in particular 25 to 50% by weight, of polyacrylic acid esters, polyesters, polytetrafluoroethylene or waxes based on fiber weight. British Patent 2008126 also describes the use of polystyrene as a matting agent for viscose rayon fibers.

WO-A-98 / 46814 describes lyocell fibers having an aspect ratio of at least 1.5 and comprising stretched domains of polyester, polyamide or olefin copolymers parallel to the axis of the fiber. The domains have a length of 70-1000 nm and a diameter of 30-400 nm. However, during commercial mass production, it has been found difficult to limit the size of the domain to this range. This document teaches that the fibers can be carded without the use of lubricants. In contrast, lyocell fibers comprising low melting thermoplastic polymers require a lubricant for carding, and the lubricant has been made to process wet fibers prior to drying during the manufacturing process.

Lyocell fibers are not naturally crimped. However, crimping is required for staple fibers. Crimps may be produced by compressing wet fibers according to the method described in EP-A-0 797,696 or by stuffer-box crimping using dry steam according to the method described in EP-A-0 703,997. Experience has shown that this dry steam process does not harm fibers but cannot produce more than 2.3 crimps / cm without damage to conventional lyocell fibers. The term "traditional lyocell fiber" as used herein refers to a lyocell fiber that does not comprise a low melting thermoplastic polymer. Therefore, only conventional lyocell fibers are used.

High speed carding of lyocell fibers can also lead to problems such as excessive fly and rolling laps of the fibers. High speed carding is required for high productivity in the manufacture of yarns, in particular nonwovens.

It is an object of the present invention to solve or reduce these problems.

The present invention relates to an improved lyocell fiber and a method for producing the improved lyocell fiber. "Fiber" in the present invention includes continuous filament yarns, tow of yarn for cutting into staple fibers and staple fibers formed from such tows.

According to the present invention, the method of the present invention for producing lyocell fibers

(i) a trace of the cellulose in an aqueous tertiary amine N-oxide solvent, the solution having a glass transition temperature below the temperature at which the solution is formed, based on the weight of the cellulose dispersed therein; To 30% by weight, in particular 0.001 to 30% by weight, preferably 0.01-20% by weight, more preferably 0.1 to 10% by weight,

(ii) extruding this solution through a mold into an aqueous coagulation bath to form lyocell fibers,

(iii) washing and drying the fibers to remove residual N-oxides,

(iv) crimping the fiber to induce 2.5 to 8 crimps / cm crimp in the fiber.

In the present invention, the trace amount means an amount sufficient to show a change in color when the fiber containing the thermoplastic polymer is dyed with a disperse dye.

The glass transition temperature (Tg) refers to the temperature range in which the polymer changes from a hard or brittle glass state where the movement of a portion of the chain, the so-called segment, is relatively unhindered by the interaction of neighboring chains. (Principles of Polymer Chemistry, Cornell University Press, 5th edition, 1992, ISBN 0-8014-0134-8, pages 56)

In a preferred embodiment of the invention, the thermoplastic polymer has a melting point of at least 50 ° C., in particular 50-150 ° C., preferably 80-130 ° C., measured by differential thermal analysis.

The glass transition temperature (Tg) of the polymer is preferably between -20 ° C and 130 ° C, particularly between 30 ° C and 130 ° C.

The thermoplastic polymer is preferably a thermoplastic polymer selected from the group consisting of polyester, polyamide and olefin polymers.

The thermoplastic polymer is preferably dispersed evenly in the lyocell with domains, and the maximum size of the domains is preferably 50 nm or less.

The fibers are preferably crimped to induce about 3.5-8 crimps / cm of crimp in the fibers.

The solution may comprise a matting agent, such as dispersed titanium dioxide, and the resulting fibers may comprise 0.1 to 5% by weight, in particular 0.1 to 2% by weight, preferably 0.2 to 1, based on the weight of the cellulose It is preferable to include by weight.

In a preferred embodiment of the present invention, the soft working agent (lubricant) is treated before crimping.

The amount of soft working agent to be treated is preferably used in the range of 0.01 to 2% by weight, in particular 0.1 to 0.5% by weight, preferably 0.15 to 0.4% by weight, based on the weight of the fiber. The crimping level that can be achieved varies depending on the amount of soft working agent to be treated, so that the amount should correspond to the lowest portion of the range of processing agents described above.

The crimp is introduced into the fiber by the method described in EP-A-0 703 997. The resulting fibers are suitably in the range of 0.5 to 5 dtex, in particular 1 to 3.5 dtex.

The process of the invention comprises the step of cutting the fibers into staple lengths ranging from 3 to 100 nm, in particular from 20 to 75 nm.

In a preferred embodiment of the present invention, after washing, the agent is treated with a chemical agent having 2 to 6 functional groups reactive with the fibers before drying so that the chemical reacts with the fibers before or during drying.

Another form of the invention

(i) forming a cellulose solution in an aqueous tertiary amine N-oxide solvent and allowing the solution to contain a low melting point thermoplastic polymer, based on the weight of dispersed cellulose, in trace amounts to 30% by weight,

(ii) extruding the resulting solution through a mold into an aqueous coagulation bath to form lyocell fibers,

(iii) washing and drying the fibers to remove amine N-oxides remaining in the fibers and

(iv) crimping the fiber to introduce about 2.5-8 crimps / cm of crimp

It provides a method for producing a lyocell fiber comprising a.

According to the present invention, the present invention provides a low melting point thermoplastic polymer based on the weight of cellulose, based on the weight of the cellulose (from the following) to 30% by weight, in particular from 0.001 to 30% by weight, preferably 0.01-10% by weight, more Preferably, 0.1-10% by weight of lyocell fibers are dispersed and crimped at 2.5-8crimps / cm.

The low melting thermoplastic polymer is preferably a thermoplastic polymer selected from the group consisting of polyester, polyamide and olefin polymers.

Surprisingly, the fibers of the present invention can be carded at significantly higher rates, in some cases carding at about twice the carding speed that can be used satisfactorily with conventional lyocell fibers. Carding speed is a very important speed limiter in the production of nonwovens. Nonwovens use matte or matte fibers, and the use of titanium oxide as a matting or matting agent does not adversely affect the process of the present invention nor does it adversely affect the fibers of the present invention, including fast carding properties. .

The lyocell fibers according to the invention may be in the form of staple fibers having a length in the range of 3-100 nm, in particular 20-75 nm.

The lyocell fibers according to the invention are preferably treated with a soft working agent in the range of 0.01 to 2% by weight, in particular 0.1 to 0.5% by weight, preferably 0.15 to 0.4% by weight.

The invention also relates to a lyocell fiber comprising a low melting thermoplastic polymer selected from the group consisting of polyesters, polyamides and olefin polymers, wherein the fibers are from 0.1 to 30% by weight, in particular from 0.5 to 0.5, based on the weight of cellulose It provides a lyocell fiber comprising 10% by weight, preferably 1-5% by weight, of low melting thermoplastic polymer and not visible when all domains are magnified x9000 by electron microscopy. All domains are 50 nm or smaller in size. However, domains may be seen, for example, when zoomed in at a high rate of x55000 times.

The lyocell fiber of the present invention is a solution of an aqueous tertiary amine N-oxide (hereinafter referred to as amine oxide), for example a cellulose solution in N-methylmorpholine N-oxide, comprising a suitable thermoplastic low melting polymer It can be prepared from. The cellulose solution described above is extruded from the spinneret through the air-gap into the aqueous coagulation bath. Extrusion temperature is typically 90-125 ° C. The fibers thus extruded are then washed and dried.

The thermoplastic low melting point polymer must be sufficiently compatible with the cellulose solution to the extent that it does not dissolve in the amine oxide when diluted with a coagulation bath or water without aggregation into a phase separated from the cellulose solution in the molten state. The polymer should be chosen to remain in the fiber during the extrusion (spinning), washing and drying processes. One form of the preferred low melting polymer is polyester, with carboxy-functional polyesters being particularly preferred.

In general, they have found that the presence of carboxylic acid groups in low melting polymers increases the compatibility with cellulose solutions, resulting in a homogeneous mixing of cellulose and low melting polymers. For most applications it is desirable for the polymer to have an acid value of at least 10, such as at least 50 to 100 and even about 150. I believe it is useful to have a branched chain polymer structure.

Examples of polyesters having the required low melting point are aliphatic dicarboxylic acids such as adipic, succinic or sebacic acid, and neopentyl glycol, ethylene glycol, propylene glycol, propane-1,3-diol, butane-1,4-diol It can be prepared from a mixture of aromatic dicarboxylic acids selected from the group consisting of isophthalic acid, terephthalic acid, and phthalic acid or anhydrides thereof, optionally having one or more aliphatic diols such as butylene glycol or diethylene glycol. The side chains can be introduced, for example, by trimellitic acid or its anhydrides or trifunctional drugs such as trimethylolpropane, glycerol or pentaerythritol. The required acid value can be obtained by using an appropriate excess of carboxylic acid-functional chemicals. Such polyesters are those sold under the trademarks "Alphtharat", "Uralak" or "Grillesta" for use in thermosetting powder coatings.

Another low melting polymer is, for example, polyamides made from fatty acid dimers and fatty acid diamines or copolyamides sold under the trademark "Gritex", or for example ethylene / vinylacetate or ethylene / butylene / butyl There are acrylate copolymers, especially copolymers containing small amounts of acrylic acid monomers to impart a suitable acid value. Another low melting thermoplastic polymer is an olefin polymer such as poly (vinyl alcohol).

The cellulose concentration in the solution to be extruded (known as spinning liquid) generally ranges from 10 to 20% by weight, in particular from at least 13 or 15% to 17 or 18% by weight. The spinning solution contains 5-15% by weight of water and the remaining 65-83% by weight of amine oxide. The extrusion temperature is generally 95-125 ° C.

The low melting polymer can be added to the cellulose solution at any stage during the fiber manufacture. For example, the polymer may be premixed with cellulose pulp to prepare a spinning solution by mixing with amine oxide and water. The polymer may also be added to the prepared cellulose solution in a molten state. It is also possible to add a relatively large amount of low melting polymer to the cellulose solution by 10-50% by weight based on the weight of the mixture to form a premix. Preprepared premixes can be used as masterbatches to add low melting polymers to the required concentration in the cellulose solution. The polymer can also be added to the amine oxide solution and the resulting mixture can be used to dissolve the cellulose.

Cellulose solutions comprising low melting polymers can be extruded at the same temperature using the same spinneret used to make conventional lyocell fibers.

It is believed that the domains of low melting polymers are uniformly dispersed in the fibers as separate phases.

The concentration of low melting polymer in the fiber ranges from trace to 30% by weight based on cellulose weight. The presence of low melting polymers has several effects depending on the concentration of the low melting polymers and the type of low melting polymers used. In particular, an amount of up to 15% by weight, in particular from 0.01 to 5% by weight, may be advantageous if only the crimping effect is desired (described below), while 1 to 20% by weight, in particular 5-15% by weight, of The amount may be advantageous if a fabric effect is desired (described later).

The required small domain of the thermoplastic polymer can be obtained in various ways. For example, the polymer can be synthesized into small particles. Large particles can also be obtained, for example, by milling or grinding, or by placing the spinning solution under high shear. The inventors have found that, unlike conventional lyocell fibers, the crimp of about 8 crimps / cm can be produced in the fibers of the present invention by the method described in EP-A-0 703 997. Moreover, the inventors have found that the parameters of crimp fixation and temperature and the parameters of the soft finish in the fibers significantly affect the fibers of the present invention as compared to conventional lyocell fibers. We also found that the crimped fibers of the present invention can have higher crimp strength at lower crimp sizes, and the lyocell fibers of the present invention are less mechanically damaged than conventional lyocell fibers.

We also found that the fibers of the present invention are significantly easier to dry than conventional lyocell fibers. This fact saves energy.

It is already known that lyocell fibers can be reacted with multifunctional reagents to reduce their fibrillation tendency. For example, EP 0 538 977, EP 0 665 904 and EP 0 755 467 have been cited in the present invention. These reactions can be carried out on undried or predried fibers. Similar reactions can be carried out in the present invention.

We have found that the fibers of the present invention comprising at least 6% by weight of low melting thermoplastic polyester react less easily with the aforementioned multifunctional drugs than conventional fibers. This phenomenon can be solved by using stronger conditions, eg higher drug concentrations.

We show that the yarns spun with the fibers of the present invention exhibit an improved fiber effect, including higher strength and elongation, contain less non-uniformity (coarse thin points and neps) and are more brushed than yarns spun from conventional fibers. I found myself flying less. This difference is more pronounced when the fibers are reacted and compared in the undried state.

Yarns spun from the crimped fibers of the present invention and fabrics woven from such yarns may be more bulging than yarns or fabrics made from conventional crimped lyocell fibers. This means that lightweight and breathable fabrics can be made from thin yarns, for example low-density yarns. Fabrics made from such thin yarns appear more uniform and more fluid. The fibers of the present invention may be continuous filaments or staple fibers.

The fibers of the present invention may be formed of a woven, knitted or nonwoven fabric (eg, hydrotangles, needle punching or heat-sealed nonwovens). Such fabrics can be subjected to conventional processing, such as anti-wrinkling resin treatment. They found that these resin treated fabrics had a clean appearance after repeated washings compared to fabrics made from conventional resin treated lyocell fibers. They also found that the fiber of the present invention comprising polyester has to be careful because sodium hydroxide tends to hydrolyze ester bonds when subjected to alkali treatment at temperatures above 50 ° C.

The fibers of the present invention can be dyed with conventional fiber dyes, for example direct dyes or reactive dyes. In general, the fibers of the present invention have lower water absorption and swellability than conventional fibers. This phenomenon means that the fibers swell less and exhibit uniformity of dyeing in certain treatments.

One known finishing method for lyocell fabrics involves introducing fibrillation into the fiber by rough wet processing and enzymatically treating and dyeing with cellulase to induce defibrillation. They have found that it is desirable to treat fabrics made with the fibers of the present invention with cellulase, which is less agglomerated than in fabrics made from conventional fibers. We also found that fabrics finished in this way are more absorbent and exhibit better wicking properties than fabrics finished in the usual way, even though the fibers themselves have low absorbency.

Low melting polymers are generally hydrophobic and can be dyed with disperse dyes. However, they have found that the fibers of the present invention dyed with disperse dyes undergo cross contamination during washing. Therefore, the dyeing of the fiber according to the present invention using a disperse dye is not recommended.

Crimping of a lyocell fiber is evaluated as follows. A fiber sample of about 200 tex is taken from the dry tow and tensioned enough to crimp. Mark every 10cm of sample length and remove tension. Calculate the crimp between the marks. The ratio of the length under tension to the length at which tension is released is the crimp strength or crimp ratio.

Hereinafter, the present invention will be described in detail by way of examples. Parts, percentages, and ratios refer to weights.

<Example 1>

A carboxy-functional saturated polyester resin of the kind used for powder coatings having an acid value of about 40, a melting point in the range of 95-130 ° C. and a branched chain structure, is prepared in a moisturizing mixer at 70 ° C. of 77/23 N-methylmorpholine N Mix with oxide (NMMO) / water. After 2 minutes, crushed woodpulp is added and mixed for 10 more minutes. The ratio of wood pulp to resin was 92.8: 7.2.

In order to remove excess water, the mixture is passed through a booth of 5.5 m ² Film Trudder (TM) unit H0055 to form a spinning solution. The mixture in the film trouser was heated by a water jacket to a temperature of 130 ° C. under a vacuum of 200 mm Hg. However, the heating temperature may be in the temperature range of 80-150 ° C., and the vacuum may be higher or lower. The mixture was sheared at high speed with a blade speed of about 5 m / sec into a layer of about 2-2.5 mm while passing through the film extruder for 10 minutes. The spinning solution contained 13.5% cellulose, 1.1% polyester, 75.4% NMMO and the remaining water.

The spinning solution was spun at a spinneret according to a conventional method and then spun through an air gap into an aqueous coagulation bath to form fibers. The fibers were dried to form a tow and crimped according to the method described in EP-A-0 703 997. The fineness of the dried fibers was 1.7 dtex and the cellulose contained 8.1% polyester and 8% moisture content. Fibers with a diameter of approximately 10 x 10 ^-6 m were produced. Figure 1 shows a cross-sectional image of the prepared fiber magnified x9000 times with a transmission electron microscope. Large black cracks appeared in the sample, but no material other than fibers. It was seen that trace amounts of polyester domains were in the fiber (presumed to correspond to about 50 nm) but substantially not all of the domains were visible. Optical magnification of the photograph shown in FIG. 1 did not reveal additional traces of the polyester domain.

The micrograph which taken the cross section of the same fiber magnified x55000 times with the transmission electron microscope is shown in FIG. 2, and the microscope picture which took the longitudinal section with the same magnification is shown in FIG.

2 and 3, the polyester domains appear as white areas. According to FIGS. 2 and 3, the visible polyester domain has a size of up to about 20 nm when compared to the scale below the figure.

The fiber has a crimp of 2.6 crimps / cm and a crimp strength of 1.3. Conventional control lyocell fibers crimped under the same conditions had a crimp strength of 2.3 crimps / cm and 1.23.

The fibers were cut into 38 mm staples and ring-spun to make 20 tex yarns. The obtained results are shown in the following table.

Control = normal lyocell fiber,

C.V.% = coefficient of variation of yarn mass in percent,

Heterogeneity index = actual C.V.% divided by the limit C.V.%,

With the limit C.V.% = 100 / √n, n is the number of fibers in the cross section (yarn tex divided by fiber tex), and the non-uniformity index 1 means perfect yarn.

Thins (-40%) = number of locations where the thickness of the yarn is 40% or less of the nominal thickness in 1 km of yarn measured by the Worcester Tester 3 test,

Thicks (+ 50%) = number of locations where the thickness of the yarn is at least 50% of the nominal thickness in 1 km of yarn measured by Worcester Tester 3 test,

Neps (+ 200%) = the number of locations where the thickness of the yarn is at least 200% of the nominal thickness in 1 km of yarn measured by the Worcester Tester 3 test,

Hairs = indirect measurement of the number and cumulative length of fibers protruding from the fiber surface measured by Worcester Tester 3 test,

TABLE 1

yarn Strength cN / tex Elongation% Uniformity C.V.% Heterogeneity Index Thins (-40%) Thicks (+ 50%) Neps (+ 200%) Hairs Control 25 7.3 13.3 1.44 87 10 15 5.85 Example 1 27 8.5 12.3 1.34 41 7 7 5.52

<Example 2>

Example 1 was repeated but crimping conditions and soft working agent concentrations were changed. Conventional fibers are crimped by the method described in EP-A-0 703 997 using a pressure of about 8 psig (55 kpa) and a vapor pressure of about 20 psig (138 kpa). High pressures resulted in uneven crimping, tow damage and blockade of the stuffer box. Unlike conventional lyocell fibers, the fibers of the present invention withstand the stronger crimping conditions (higher stuffer box pressure, higher vapor pressure and higher squeeze roller pressure) that can cause fatal damage to conventional lyocell fibers. It was. These stronger pressure conditions can produce more crimp per cm of fiber. As already known, treatment of carding lubricants with conventional lyocell fibers has not been found to have a significant effect on crimp parameters. WO-A-98 / 46814 describes that lyocell fibers comprising polyester can be carded without treatment of lubricants. Unexpectedly, it has been found that the lyocell fibers of the present invention have a very significant effect on the crimp parameters of the fiber when the soft working agent or lubricant is added. 4 shows the benefit of increasing lubricant concentration increase over the crimp level achievable at maximum. Increasing the soft finish from 0.17% to 0.35% shows that the maximum number of crimps increases from 3.5 to 5 per cm. The figure also shows that the maximum stuffer box pressure can be increased more than two times compared to conventional lyocells. Moreover, the figure shows that the increase in the maximum crimp is directly related to the increase in the soft working agent concentration. Low pressures resulted in fibers with similar values of crimp per cm as compared to conventional crimped fibers but showed reduced crimp strength with reduced crimp width.

<Example 3>

The method of Example 1 was repeated but for antifibrillation treatment 1,3,5-triacryloylhexahydro-1,3,5-hexahydrotriazine (TAHT) as described in EP-A-0,755,467. Is treated to undried fiber at a concentration of 0.7% by weight of the fiber. In the following table, the control is yarn spun into fibers with conventional lyocells treated with 0.7% TAHT. Experimental results for yarns made of treated fibers are shown in the following table.

TABLE 2

yarn Crimp (per cm) Strength cN / tex Elongation% Heterogeneity Index Thins (-30%) Thins (-40%) Thicks (+ 50%) Thicks (+ 200%) Hairs Control 24 24 7.9 1.48 1049 72 62 48 6.37 Example 3 24 25 8.2 1.32 595 29 23 31 5.30 Example 3 30 26 8.5 1.32 590 25 12 19 5.05 Example 3 40 26 8.8 1.27 443 14 13 13 5.09

Single-jersey knits made by dyeing yarns prepared by spinning the treated fiber furnace of the present invention showed no fibrillation after 10 wash / tumbling at 40 ° C.

<Example 4>

4 weight percent of dispersed thermoplastic carboxy-functional saturated polyesters using 1.7 dtex of lyocell fibers for powder coatings having a melting point and branched chain structure of about 40, 95-130 ° C., based on the weight of cellulose, and From a solution of cellulose in NMM) comprising 0.5% by weight of titanium dioxide, a matting and reducing agent, using a conventional method. The fibers are washed and treated with 0.25% by weight soft working agent based on the weight of the fiber. The fibers are dried and then compressed in a stuffer box in the presence of dry steam to introduce crimps into the fibers. The conditions under which the fibers are crimped are shown in the following table and the physical properties are shown in the graph of FIG.

TABLE 5

Stufferbox Pressure (psig) Relative Stufferbox Pressure Average crimp rate (crimps / 10cm) 8 One 25 20 2.5 35 26 3.3 40

The fibers are cut into 38 mm staple lengths.

The fibers are carded in a Tiview CA 11 2.5 m wide with a double doped roller. The basis weight of the carded web was 30 gsm. The following results were obtained from the fiber of the present invention and the control fiber.

table

Carding speed, m / min Fiber of Example 4, 2.5 crimps / cm ca.140 Fiber of Example 4, 3.5crimps / cm 200-220 Fiber of Example 4, 4.0crimps / cm 250-270 Control fiber, 2.3crimps / cm 100 Viscous ca 150 Polyester 200+ Polypropylene ca 250

Due to instability in the crimping step, high crimping rates were not obtained with conventional control fibers. On the other hand, the fibers of the present invention were crimped more stably under high pressure than conventional control fibers, and crimps introduced under a given pressure showed higher fibers of the present invention than conventional fibers.

Claims (51)

(i) a trace amount based on the weight of the dispersed cellulose in which the cellulose is dissolved in an aqueous tertiary amine N-oxide solvent and the solution has a glass transition temperature below the temperature at which the solution forms To 30% by weight), (ii) extruding this solution through a mold into an aqueous coagulation bath to form lyocell fibers, (iii) washing and drying the fibers to remove residual amine N-oxides, (iv) crimping the fiber to introduce a crimp of 2.5 to 8 crimps / cm into the fiber Method for producing a lyocell fiber comprising a. The method of claim 1 wherein the cellulose solution comprises 0.001 to 30 weight percent thermoplastic polymer particles. The method of claim 2 wherein the cellulose solution comprises from 0.01 to 20% by weight thermoplastic polymer particles. The method of claim 2 wherein the cellulose solution comprises 0.1 to 10 weight percent thermoplastic polymer particles. 5. The method of claim 1, wherein the low melting thermoplastic polymer has a melting point of at least 50 ° C. 6. The method of claim 5 wherein the thermoplastic polymer has a melting point between 50 ° C. and 150 ° C. 7. 7. The method of claim 6, wherein the thermoplastic polymer has a melting point between 80 ° C and 130 ° C. 8. The method of claim 1, wherein the thermoplastic polymer has a glass transition temperature between −20 ° C. and 130 ° C. 9. The method of claim 8, wherein the thermoplastic polymer has a glass transition temperature between 30 ° C. and 130 ° C. 10. 10. The method of any one of claims 1 to 9, wherein the thermoplastic polymer is a thermoplastic polymer selected from the group consisting of polyester, polyamide and olefin polymers. The method of any one of claims 1 to 10, wherein the thermoplastic polymer is evenly dispersed in the lyocell into domains, and the maximum size of all domains is 50 nm or less. The method according to any one of claims 1 to 11, wherein the washed fibers treat the soft working agent before crimping. 13. The method of claim 12 wherein the soft processing agent is treated at a concentration of 0.01 to 2 weight percent based on the weight of the fiber. The method of claim 13, wherein the soft processing agent is treated at a concentration of 0.1 to 0.5% by weight, based on the weight of the fiber. The method of claim 14 wherein the soft processing agent is treated at a concentration of 0.15 to 0.4% by weight of the fiber. 16. The method of any one of claims 1 to 15, wherein the fibers are crimped to introduce crimps into the fibers at 3.5 to 8 crimps / cm. 17. The method of any one of claims 1 to 16, wherein the solution comprises a matting agent for matting the fibers. The method of claim 17, wherein the solution comprises dispersed titanium dioxide powder acting as a matting agent and the resulting fiber comprises 0.1 to 5 wt% dispersed titanium dioxide powder based on the weight of the cellulose. . The method of claim 18, wherein the solution comprises dispersed titanium dioxide powder and the resulting fiber comprises 0.1 to 2 weight percent dispersed titanium dioxide powder based on the weight of cellulose. The method of claim 18, wherein the solution comprises dispersed titanium dioxide powder and the resulting fiber comprises 0.2 to 1 weight percent dispersed titanium dioxide powder based on the weight of cellulose. 21. The method of any of claims 1 to 20, wherein the method further comprises cutting the fibers into staples of length ranging from 3 to 100 mm. The method of claim 21, wherein the fibers are cut into staples in the range of 20 to 75 mm in length. The method of claim 1, wherein the resulting fiber has a fineness in the range of 0.5 to 5 dtex. The method of claim 23 wherein the resulting fiber has a fineness in the range of 1 to 3.5 dtex. The method as claimed in any one of claims 1 to 24, characterized in that the fibers are reactive with cellulose so that they are treated with a drug having 2 to 6 functional groups which react with the fibers before and after drying and then before drying. Same way as that. A method for carding and processing fibers formed by any of claims 21-25. 27. The fiber of claim 26 wherein the fiber produced by the method according to any of claims 21 to 25 is processed into a card having a weight of 30 gsm and the web is fed at a rate of 150-275 m / min in a TiVue CA 11 carding machine. Or carding at a similar speed on a similar carding machine. A lyocell fiber comprising a trace of 30 to 30% by weight of a low melting thermoplastic polymer, dispersed in the fiber, based on the weight of cellulose, and having a crimp of 2.5 to 8 crimps / cm. The lyocell fiber of claim 28 wherein the low melting thermoplastic polymer is dispersed between 0.001 and 30% by weight in the fiber. The lyocell fiber of claim 29 wherein the low melting thermoplastic polymer is dispersed in the fiber at 0.01 to 20 wt%. 31. The lyocell fiber of claim 30 wherein the low melting thermoplastic polymer is dispersed from 0.1 to 10% by weight in the fiber. 32. The lyocell fiber according to any one of claims 28 to 31, wherein the low melting thermoplastic polymer is a low melting thermoplastic polymer selected from the group consisting of polyester, polyamide and olefin polymers. 33. The method of any one of claims 28 to 32, wherein the fiber comprises a drug having from 2 to 6 functional groups reactive with cellulose, which agent is treated with undried fiber to react with the fiber before or during drying. Lyocell fiber characterized in that. 34. The lyocell fiber according to any one of claims 28 to 33, wherein the thermoplastic polymer is evenly dispersed in the lyocell in the domain state and the maximum size of all domains is 50 nm or less. 35. The lyocell fiber according to any one of claims 28 to 34, wherein from 0.1 to 5% by weight titanium dioxide powder, based on the weight of cellulose, is dispersed in the fiber. 36. The lyocell fiber of claim 35 wherein 0.1 to 2 percent by weight titanium dioxide powder, based on the weight of cellulose, is dispersed in the fiber. 37. A lyocell fiber according to claim 36 wherein 0.2-1% by weight titanium dioxide powder, based on the weight of cellulose, is dispersed in the fiber. 38. The lyocell fiber according to any one of claims 28 to 37, wherein the fiber has a fineness of 0.5 to 5 dtex. 39. The lyocell fiber of claim 38 wherein the fiber has a fineness of 1 to 3.5 dtex. 40. A lyocell fiber according to any one of claims 28 to 39, wherein the fiber is a staple fiber having a length in the range of 3 to 100 mm. 41. The lyocell fiber of claim 40 wherein the fiber is a staple fiber having a length in the range of 20 to 75 mm. 42. The lyocell fiber according to any one of claims 28 to 41 wherein the fiber has been treated with 0.01 to 2% by weight of a soft finish based on the weight of the fiber. 43. The lyocell fiber of claim 42 wherein the fiber has been treated with from 0.1 to 0.5% by weight of a soft finish based on the weight of the fiber. 44. The lyocell fiber of claim 43 wherein the fiber has been treated with from 0.15 to 0.4 weight percent softener based on the weight of the fiber. For lyocell fibers comprising domains of low melting thermoplastic polymers selected from the group consisting of polyester, polyamide and olefin polymers, the fibers comprise from 0.1 to 30% by weight of low melting thermoplastic polymers, Lyocell fiber, characterized in that the domain is not visible when x9000 times magnified by an electron microscope. For lyocell fibers comprising domains of low melting thermoplastic polymers selected from the group consisting of polyester, polyamide and olefin polymers, the fibers comprise from 0.1 to 30% by weight of low melting thermoplastic polymers, The lyocell fiber, characterized in that the maximum size of the domain is 50nm or less. 47. The lyocell fiber of claim 45 or 46 wherein the fiber comprises from 0.5 to 10 weight percent of a low melting thermoplastic polymer. 48. The lyocell fiber of claim 47 wherein the fiber comprises from 1 to 5% by weight of a low melting thermoplastic polymer. A method for producing lyocell fibers as described in the detailed description of the invention and described in the Examples. Lyocell fibers as described in the detailed description of the invention and described in the Examples. (i) forming a solution of cellulose in an aqueous tertiary amine N-oxide solvent and allowing the solution to contain a low melting point thermoplastic polymer, based on the weight of dispersed cellulose, in trace amounts to 30% by weight, (ii) extruding the resulting solution through a mold into an aqueous coagulation bath to form lyocell fibers, (iii) washing and drying the fibers to remove amine N-oxides remaining in the fibers and (iv) crimping the fiber to introduce about 2.5-8 crimps / cm of crimp Method for producing a lyocell fiber comprising a