Lyocell fibers, processes for their production and use thereof

Abstract

The application relates to a lyocell fiber and a preparation method and application thereof. The preparation method comprises the following steps: mixing first pulp, polyacrylamide and an aqueous solution of N-methylmorpholine-N-oxide to prepare a first spinning solution; mixing second pulp and an aqueous solution of N-methylmorpholine-N-oxide to prepare a second spinning solution, wherein the polymerization degree of the first pulp is greater than that of the second pulp, and the difference is greater than or equal to 100; spinning the first spinning solution and the second spinning solution to obtain a parallel solution flow, blowing and cooling the side where the first spinning solution is located in the parallel solution flow to be shaped, and performing drying treatment, so that the first spinning solution forms a first fiber, the second spinning solution forms a second fiber, and a lyocell fiber in which the first fiber and the second fiber are distributed in parallel is obtained; and the temperature of the drying treatment is greater than or equal to the glass transition temperature of the polyacrylamide. The lyocell fiber has a three-dimensional spiral curling structure, and has excellent curling degree, compression resilience and curling recovery.

Description

Technical Field

[0001] This invention relates to the field of lyocell fiber technology, and in particular to a lyocell fiber, its preparation method, and its applications. Background Technology

[0002] Lyocell fiber combines the excellent properties of both natural and synthetic fibers. As a green fiber, its raw material is the inexhaustible cellulose found in nature. The production process involves no chemical reactions and uses non-toxic solvents, thus attracting significant attention from the polymer materials industry both domestically and internationally in recent years. Typically, lyocell fiber is used in textiles and clothing fabrics. Garments made from it not only have a natural luster, smooth feel, high strength, and minimal shrinkage, but also excellent moisture permeability, breathability, and perspiration wicking properties. However, because lyocell fiber has poorer compression resilience and crimp recovery compared to synthetic fiber fillers, it suffers from rebound failure after repeated compressions. Therefore, the industry currently rarely uses lyocell fiber as a filler in lyocell products. Summary of the Invention

[0003] Therefore, it is necessary to provide a lyocell fiber, its preparation method, and its application to address the above-mentioned problems. This preparation method can obtain lyocell fibers with a three-dimensional helical crimp structure, which have excellent crimp, high compression resilience, and crimp recovery properties, and can be used as a filling material in home textile products.

[0004] A method for preparing lyocell fiber includes the following steps:

[0005] The first spinning solution is prepared by mixing the first pulp, polyacrylamide, and an aqueous solution of N-methylmorpholine-N-oxide.

[0006] The second pulp is mixed with an aqueous solution of N-methylmorpholine-N-oxide to prepare a second spinning solution, wherein the degree of polymerization of the first pulp is greater than that of the second pulp, and the difference is ≥100.

[0007] The first spinning solution and the second spinning solution are spun to obtain a parallel solution flow. The side of the parallel solution flow containing the first spinning solution is cooled and shaped by blowing air. After solidification bath molding and drying treatment, the first spinning solution forms a first fiber and the second spinning solution forms a second fiber, resulting in lyocell fiber with the first and second fibers distributed side by side. The drying temperature is greater than or equal to the glass transition temperature of polyacrylamide.

[0008] In one embodiment, the degree of polymerization of the first pulp is 600 to 1200.

[0009] In one embodiment, the degree of polymerization of the second pulp is 400 to 600.

[0010] In one embodiment, the polyacrylamide has a molecular weight of 200,000 to 20,000,000.

[0011] In one embodiment, the mass fraction of each component in the first spinning solution is: 9% to 13% first pulp, 1% to 10% polyacrylamide, 74% to 78% N-methylmorpholine-N-oxide, and 9% to 13% water.

[0012] In one embodiment, the mass fraction of each component in the second spinning solution is: 9% to 13% of first pulp, 74% to 78% of N-methylmorpholine-N-oxide, and 9% to 13% of water.

[0013] In one embodiment, the area ratio of the first spinning solution to the second spinning solution in the cross-section of the parallel solution flow is 2:3 to 3:2.

[0014] In one embodiment, the airflow speed for the blowing cooling and shaping is 35 m / min to 45 m / min, the temperature is 10°C to 20°C, and the humidity is 70% to 80%.

[0015] Lyocell fibers prepared by the method described above have a three-dimensional helical crimp structure, wherein a first fiber and a second fiber are arranged side by side, and the first fiber is located inside the three-dimensional helical crimp structure of the lyocell fiber.

[0016] In one embodiment, the crimp of the lyocell fiber is 15% to 23%.

[0017] In one embodiment, the elastic recovery rate of the lyocell fiber is ≥70%.

[0018] In one embodiment, the cross-section of the lyocell fiber has an area ratio of 2:3 to 3:2 for the first fiber to the second fiber.

[0019] The application of lyocell fiber as a filling material in home textile products, as described above.

[0020] In the method for preparing lyocell fiber described in this invention, a first spinning solution is prepared using a high-polymerization-degree pulp, polyacrylamide, and an aqueous solution of N-methylmorpholine-N-oxide (NMMO). A second spinning solution is prepared using a low-polymerization-degree pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO). The two spinning solutions with different components are then spun to obtain a parallel solution stream. Simultaneously, the side of the parallel solution stream containing the first spinning solution is cooled and shaped by blowing air, causing the molecular chains of polyacrylamide and the first pulp to be oriented along the fiber axis. In a rapid-setting state, the polyacrylamide and cellulose molecules in the first pulp are quickly fixed in the fiber. Under subsequent drying conditions, on the one hand, the straightened polyacrylamide and cellulose molecules in the first pulp relax and return to their natural curled state, pulling the two ends of the molecular chain segments towards the middle; on the other hand, the first pulp has a higher degree of polymerization than the second pulp, and its cellulose has longer molecular chains, resulting in a better shrinkage effect when curling. This macroscopically causes the side of the lyocell fiber where the first fiber is located to shrink axially, thus obtaining lyocell fiber with a three-dimensional helical curled shape.

[0021] Therefore, the lyocell fiber obtained by this invention has excellent crimp, compression resilience and crimp recovery, as well as good dimensional stability, toughness and elasticity and moisture absorption and perspiration wicking properties. When used as filling material for bedding such as quilts and pillows, it can greatly improve the comfort of consumers. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the drying shrinkage of Lyocell fibers;

[0024] Figure 2 This is a schematic diagram of the cross-section of Lyocell fiber;

[0025] Figure 3 This is a photograph of the Lyocell fiber prepared in Example 1.

[0026] Among them, 10 is the first fiber; 20 is the second fiber; 101 is a straightened oriented polyacrylamide chain; and 102 is a disoriented polyacrylamide chain. Detailed Implementation

[0027] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0029] This invention provides a method for preparing lyocell fibers, characterized by comprising the following steps:

[0030] S1, mix the first pulp, polyacrylamide and an aqueous solution of N-methylmorpholine-N-oxide to prepare the first spinning solution;

[0031] S2, the second pulp is mixed with an aqueous solution of N-methylmorpholine-N-oxide to prepare a second spinning solution, wherein the degree of polymerization of the first pulp is greater than that of the second pulp, and the difference is ≥100;

[0032] S3, the first spinning solution and the second spinning solution are spun to obtain a parallel solution flow, and the side of the parallel solution flow containing the first spinning solution is cooled and shaped by blowing air. After solidification bath molding and drying treatment, the first spinning solution forms a first fiber and the second spinning solution forms a second fiber, resulting in lyocell fiber with the first fiber and the second fiber distributed in parallel. The drying temperature is greater than or equal to the glass transition temperature of polyacrylamide.

[0033] In steps S1 and S2, two spinning solutions are prepared using two types of pulp with a degree of polymerization difference ≥100. Polyacrylamide is added to the spinning solution prepared with the pulp of higher degree of polymerization. Since the two spinning solutions have different components, the parallel solution flows have two different properties. The first pulp has a higher degree of polymerization than the second pulp, and its cellulose molecular chains are longer. At a certain temperature, the first pulp exhibits better curling effect than the second pulp. Furthermore, the first pulp has a higher dynamic viscosity, and the addition of high-viscosity polyacrylamide has a smaller impact on its overall viscosity, thus giving the spinning solution system better stability.

[0034] Preferably, the degree of polymerization of the first pulp is 600 to 1200, and / or the degree of polymerization of the second pulp is 400 to 600, which can effectively ensure the crimp, dimensional stability and crimp resilience of lyocell fibers.

[0035] In one embodiment, the mass fraction of each component in the first spinning solution is: 9% to 13% first pulp, 1% to 10% polyacrylamide, 74% to 78% N-methylmorpholine-N-oxide (NMMO), and 9% to 13% water.

[0036] In one embodiment, the mass fraction of each component in the second spinning solution is: 9% to 13% of first pulp, 74% to 78% of N-methylmorpholine-N-oxide (NMMO), and 9% to 13% of water.

[0037] The aqueous solution of N-methylmorpholine-N-oxide (NMMO) used in the first and second spinning solutions is a commonly used solvent in the production process of cellulose fibers, and has the advantages of being non-toxic and recyclable.

[0038] In one embodiment, the polyacrylamide has a molecular weight of 200,000 to 20,000,000 and has a water-soluble polyacrylamide macromolecule, which can achieve better deorientation effect at a specific temperature.

[0039] Preferably, the polyacrylamide has a molecular weight of 200,000 to 10,000,000, which not only helps to improve the curling effect of polyacrylamide, but also ensures the water solubility of polyacrylamide and improves its dissolution effect in the first spinning solution.

[0040] It should be noted that the order of preparation of steps S1 and S2 is not affected. It is feasible to prepare step S1 first and then step S2, or to prepare step S2 first and then step S1, or to prepare steps S1 and S2 simultaneously.

[0041] In step S3, two different components of spinning solution are spun to obtain a parallel solution stream. By blowing air to cool and fix the side of the parallel solution stream containing high-polymerization pulp and polyacrylamide, the axially oriented molecular chains of pulp cellulose and polyacrylamide can be quickly fixed in the fiber. At the same time, the side of the parallel solution stream containing low-polymerization pulp is naturally cooled without blowing air. Before slowly dropping to the glass transition temperature of low-polymerization pulp, some pulp cellulose molecular chains undergo spontaneous deorientation and are fixed in a coiled state in the macroscopically straight fiber.

[0042] Furthermore, during the drying process, such as Figure 1As shown, on the one hand, since the drying temperature exceeds the glass transition temperature of polyacrylamide, the molecular chains of the straightened and oriented polyacrylamide 101 and the cellulose in the first pulp relax and return to their natural curled state. The disoriented polyacrylamide chains 102 pull the two ends of the molecular chain segments to shrink towards the middle. At the same time, based on the difference in the degree of polymerization between the first pulp and the second pulp, lyocell fiber achieves excellent curling and shrinkage effect.

[0043] On the other hand, during the natural cooling process of the second pulp, some of the pulp cellulose molecular chains have already curled up and been fixed in the macroscopically straightened fibers, so they cannot be further curled up during the drying process, which is conducive to further increasing the shrinkage difference on both sides of the lyocell fiber.

[0044] Therefore, on a macroscopic level, the side containing the first fiber in the lyocell fiber experiences axial shrinkage, and the side containing the second fiber is passively bent due to the shrinkage of the first fiber, thus resulting in a lyocell fiber exhibiting a three-dimensional helical crimp shape.

[0045] Furthermore, the preparation method provided by this invention is an improvement on the conventional lyocell fiber production process, which has stable production process and low production cost. At the same time, the air blowing cooling and shaping treatment used in this invention has the advantages of high safety and simple operation. Therefore, the preparation method of lyocell fiber provided by this invention is conducive to further scale-up production.

[0046] In one embodiment, after the solidification bath and before the drying process, the preparation method further includes bundling, stretching, washing, cutting and refining processes. All of the above processes adopt existing processing methods, and the present invention does not limit them. For example, bundling can be performed using conventional bundling devices to gather parallel fibers into large strands of a certain linear density under uniform tension; drawing can be performed by passing the bundled parallel fibers, whose microstructure is not yet fully fixed, through the gaps between two or three sets of guide rollers or guide discs with different rotation speeds. The speed difference between the two guide rollers or guide discs causes the parallel fibers to elongate and the molecular chains of the crimped and disordered macromolecules to align and extend axially to achieve ordering, increase the contact points between macromolecules, and improve tensile strength; washing can be performed by passing the parallel fibers through one or two consecutively arranged washing tanks to remove the solution and organic and inorganic impurities adhering to the surface of the parallel fibers, or by spraying a cleaning solution onto the moving parallel fibers until the filaments are clean; cutting can be performed by wet cutting, dry cutting, or drawing cutting; refining can be performed by chemical refining methods or physical refining methods to remove impurities, dirt, and residual sizing from the parallel fibers.

[0047] Furthermore, the present invention does not limit the apparatus used for spinning in step S3; any apparatus capable of ejecting parallel flow of solution is acceptable.

[0048] In one embodiment, the area ratio of the first spinning solution to the second spinning solution in the cross-section of the parallel solution flow is 2:3 to 3:2.

[0049] Preferably, in the cross-section of the parallel solution flow, the area ratio of the first spinning solution to the second spinning solution is 1:1, and the first spinning solution and the second spinning solution are equally distributed on the left and right sides, so that the resulting lyocell fiber has two different properties on both sides, thereby generating a shrinkage difference during the drying process. The lyocell fiber can curl towards the side where the first fiber is located. The lyocell fiber produced by the parallel solution flow with this area ratio has the best curlability.

[0050] In one embodiment, the air velocity for the blowing cooling and shaping is 35 m / min to 45 m / min, the temperature is 10°C to 20°C, and the humidity is 70% to 80%. At this time, the first spinning solution can be rapidly cooled, and the molecular chains of polyacrylamide and first pulp cellulose in the first spinning solution can be rapidly shaped in a straightened state under the dual action of solution flow stretching and blowing cooling and shaping.

[0051] It should be noted that the airflow direction in the blowing cooling and shaping process can be directly facing the first spinning solution and perpendicular to the axis of the parallel solution flow, or it can be facing the first spinning solution and at a certain angle to the axis of the parallel solution flow. This invention does not limit this.

[0052] Polyacrylamide of different molecular weights has different glass transition temperatures. When the drying temperature is 150℃~170℃, the glass transition temperature of polyacrylamide can generally be reached, so that the polyacrylamide molecular chains can be deoriented and restored to their natural curled state, and the lyocell fiber can be bent on one side. At the same time, it can also avoid the problem of discoloration of lyocell fiber caused by excessive temperature.

[0053] The present invention also provides a lyocell fiber prepared by the method described above, wherein the lyocell fiber has a three-dimensional helical crimp structure and the lyocell fiber includes a first fiber and a second fiber arranged in parallel, wherein the first fiber is located inside the three-dimensional helical crimp structure of the lyocell fiber.

[0054] The lyocell fiber of the present invention has a uniform, permanent three-dimensional helical crimp structure. The lyocell fiber has a fluffy feel, excellent resilience, and also possesses the excellent moisture-wicking properties of cellulose fiber. Moreover, the tensile strength of the lyocell fiber can reach 3.6 cN / dtex to 4.4 cN / dtex, and the elongation at break is about 10% to 14%, exhibiting excellent mechanical properties.

[0055] In one embodiment, the crimp of the lyocell fiber is 15% to 23%.

[0056] In one embodiment, the elastic recovery rate of the lyocell fiber is ≥70%.

[0057] In one embodiment, the cross-section of the lyocell fiber has an area ratio of 2:3 to 3:2 between the first fiber and the second fiber.

[0058] Preferably, in the cross-section of the lyocell fiber, the area ratio of the first fiber to the second fiber is 1:1, such as... Figure 2 As shown, the first fiber 10 and the second fiber 20 are equally distributed on both sides of the lyocell fiber.

[0059] The application of lyocell fiber as a filling material in home textile products, as described above.

[0060] When the lyocell fiber of the present invention is used as a filling material for textiles that come into contact with the human body, it has excellent resilience and can quickly absorb and expel sweat produced by the human body, which can greatly improve the comfort of consumers during use.

[0061] The following specific embodiments will further illustrate the lyocell fiber, its preparation method, and its application.

[0062] The two spinning solutions in Examples 1-12 were prepared according to the formulations in Tables 1 and 2, respectively.

[0063] Table 1

[0064]

[0065] Table 2

[0066]

[0067]

[0068] The preparation steps of the spinning solution and lyocell fiber in Examples 1-12 and Comparative Examples 1-8 are as follows:

[0069] Example 1

[0070] Select the appropriate first pulp and polyacrylamide according to the formula in Table 1, and mix the first pulp, polyacrylamide and aqueous solution of N-methylmorpholine-N-oxide (NMMO) according to the formula in Table 1 to prepare the first spinning solution.

[0071] Select the appropriate second pulp according to the formula in Table 2, and mix the second pulp with an aqueous solution of N-methylmorpholine-N-oxide (NMMO) according to the formula in Table 2 to prepare the second spinning solution;

[0072] The first and second spinning solutions are added to a spinning device for spinning to obtain a parallel solution flow. The area ratio of the first spinning solution to the second spinning solution in the cross-section is 1:1. The side of the parallel solution flow containing the first spinning solution is cooled and shaped by blowing air at a speed of 35 m / min, a temperature of 15°C, and a humidity of 75%. The solution is then shaped, bundled, drawn, washed, cut, refined, and dried. The drying temperature is 150°C, and finally, lyocell fiber is obtained.

[0073] Lyocell fibers prepared in Example 1, such as Figure 3 As shown, it has a three-dimensional spiral curl structure.

[0074] Example 2

[0075] The difference between Example 2 and Example 1 is that the area ratio of the first spinning solution to the second spinning solution is 2:3.

[0076] Example 3

[0077] The difference between Example 3 and Example 1 is that the drying temperature is 155°C.

[0078] Example 4

[0079] The difference between Example 4 and Example 1 is that the drying temperature is 160°C.

[0080] Example 5

[0081] The difference between Example 5 and Example 1 is that the airflow speed for cooling and shaping the side of the first spinning solution in the parallel solution flow is 40 m / min, the temperature is 10°C, and the humidity is 70%.

[0082] Example 6

[0083] The difference between Example 6 and Example 1 is that the amount of polyacrylamide added in the first spinning solution is 5%.

[0084] Example 7

[0085] The difference between Example 7 and Example 1 is that the amount of polyacrylamide added in the first spinning solution is 10%.

[0086] Example 8

[0087] The difference between Example 8 and Example 1 is that the degree of polymerization of the first pulp is 600 and the degree of polymerization of the second pulp is 500.

[0088] Example 9

[0089] The difference between Example 9 and Example 1 is that the degree of polymerization of the first pulp is 1000 and the degree of polymerization of the second pulp is 600.

[0090] Example 10

[0091] The difference between Example 10 and Example 1 is that the degree of polymerization of the first pulp is 1200 and the degree of polymerization of the second pulp is 600.

[0092] Example 11

[0093] The difference between Example 11 and Example 1 is that the molecular weight of the polyacrylamide is 500,000.

[0094] Example 12

[0095] The difference between Example 12 and Example 1 is that the molecular weight of the polyacrylamide is 10 million.

[0096] Comparative Example 1

[0097] The difference between Comparative Example 1 and Example 1 is that the drying temperature is 100°C.

[0098] Comparative Example 2

[0099] The difference between Comparative Example 2 and Example 1 is that the parallel solution stream is not subjected to air cooling and shaping treatment, and the parallel solution stream obtained by spinning is directly subjected to coagulation bath forming, bundling, stretching, washing, cutting, refining and drying treatment.

[0100] Comparative Example 3

[0101] The difference between Comparative Example 3 and Example 1 is that both sides of the first and second spinning solutions in the parallel solution flow are subjected to air blowing cooling and shaping treatment.

[0102] Comparative Example 4

[0103] The difference between Comparative Example 4 and Example 1 is that the degree of polymerization of both the first pulp and the second pulp is 600.

[0104] Comparative Example 5

[0105] The difference between Comparative Example 5 and Example 1 is that the degree of polymerization of the first pulp is 650 and the degree of polymerization of the second pulp is 600.

[0106] Comparative Example 6

[0107] The difference between Comparative Example 6 and Example 1 is that the degree of polymerization of the first pulp is 500 and the degree of polymerization of the second pulp is 600.

[0108] Comparative Example 7

[0109] The difference between Comparative Example 7 and Example 1 is that no polyacrylamide was added to the first spinning solution.

[0110] Comparative Example 8

[0111] The difference between Comparative Example 8 and Example 1 is that no polyacrylamide is added to the first spinning solution, while polyacrylamide (molecular weight 5 million, addition amount 2%) is added to the second spinning solution, and the first spinning solution is cooled and shaped by blowing air onto the side of the parallel solution stream sprayed from the spinning device.

[0112] The lyocell fibers prepared in Examples 1-12 and Comparative Examples 1-8 were subjected to performance tests. The test indicators and test methods are as follows:

[0113] (1) Curl test: First, clamp one end of a single lyocell fiber, then apply light and heavy loads to the other end respectively, measure the length of the lyocell fiber and calculate the curl. The calculation formula is as follows:

[0114]

[0115] Where J is the fiber crimp, L0 is the fiber length (mm) measured under light load, and L1 is the fiber length (mm) measured under heavy load.

[0116] (2) Elastic recovery rate test: First, clamp one end of a single lyocell fiber, then apply light, heavy, and heavy loads to the other end respectively, hold for 30 seconds, and release. After 2 minutes of recovery, apply a light load again and measure the length of the lyocell fiber. Calculate the elastic recovery rate using the following formula:

[0117]

[0118] Among them, J d L is the fiber elastic recovery rate, L0 is the fiber length (mm) measured under light load, L1 is the fiber length (mm) measured under heavy load, and L is the fiber length (mm) measured after being released from heavy load for 30 seconds, recovering for 2 minutes, and then being reloaded with light load.

[0119] The performance tests of the Lyocell fibers prepared in Examples 1-12 and Comparative Examples 1-8 are shown in Table 3.

[0120] Table 3

[0121]

[0122]

[0123] The test results in Table 3 show that, compared with Comparative Examples 1-3, the Lyocell fibers obtained by blowing and cooling the spinning solution containing polyacrylamide and high-polymerization pulp on one side, and by high-temperature drying treatment with a glass transition temperature higher than that of polyacrylamide, exhibit excellent crimp and elastic recovery. Furthermore, comparing Examples 1-12 with Comparative Examples 4-8 reveals that by selecting two types of pulp with a polymerization degree difference ≥100 and using polyacrylamide in the high-polymerization pulp, the Lyocell fibers obtained by this invention exhibit excellent crimp, compression resilience, and crimp recovery.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A process for the production of lyocell fibres characterised in that, Includes the following steps: The first spinning solution is prepared by mixing the first pulp, polyacrylamide, and an aqueous solution of N-methylmorpholine-N-oxide. The second pulp is mixed with an aqueous solution of N-methylmorpholine-N-oxide to prepare a second spinning solution, wherein the degree of polymerization of the first pulp is greater than that of the second pulp, and the difference is ≥100. The first spinning solution and the second spinning solution are spun to obtain a parallel solution flow. The side of the parallel solution flow containing the first spinning solution is cooled and shaped by blowing air. After solidification bath molding and drying treatment, the first spinning solution forms a first fiber and the second spinning solution forms a second fiber, resulting in lyocell fiber with the first fiber and the second fiber distributed in parallel. The drying treatment temperature is greater than or equal to the glass transition temperature of polyacrylamide. In the cross-section of the parallel-type solution flow, the area ratio of the first spinning solution to the second spinning solution is 2:3 to 3:

2.

2. The process for the production of lyocell fibers according to claim 1, characterized in that, The degree of polymerization of the first pulp is 600~1200; And / or, the degree of polymerization of the second pulp is 400 to 600.

3. The process for the production of lyocell fibers according to claim 1, characterized in that, The molecular weight of the polyacrylamide is 200,000 to 20,000,000.

4. The process for the production of lyocell fibers according to claim 1, characterized in that, The mass fractions of each component in the first spinning solution are: 9%~13% first pulp, 1%~10% polyacrylamide, 74%~78% N-methylmorpholine-N-oxide, and 9%~13% water.

5. The process for the production of lyocell fibers according to claim 1, characterized in that, The mass fractions of each component in the second spinning solution are: 9%~13% first pulp, 74%~78% N-methylmorpholine-N-oxide, and 9%~13% water.

6. The process for the production of lyocell fibers according to claim 1, characterized in that, In the cross-section of the parallel-type solution flow, the area ratio of the first spinning solution to the second spinning solution is 1:

1.

7. The process for the production of lyocell fibers according to claim 1, characterized in that, The airflow speed for the blowing cooling and shaping is 35m / min to 45m / min, the temperature is 10℃ to 20℃, and the humidity is 70% to 80%.

8. Lyocell fiber obtainable by the process according to any one of claims 1 to 7, characterized in that The lyocell fiber has a three-dimensional helical crimp structure, and the lyocell fiber includes a first fiber and a second fiber arranged in parallel, with the first fiber located inside the three-dimensional helical crimp structure of the lyocell fiber.

9. Lyocell fibre according to claim 8, characterized in that The crimp of the lyocell fiber is 15%~23%; And / or, the elastic recovery rate of the lyocell fiber is ≥70%; And / or, in the cross-section of the lyocell fiber, the area ratio of the first fiber to the second fiber is 2:3 to 3:

2.

10. The use of lyocell fiber as a filling material in home textile products as described in claim 8 or claim 9.

Images