Regenerated cellulose fiber and preparation method thereof

Abstract

The present application provides a method for preparing regenerated cellulose fiber, comprising the following steps: S1, mixing cellulose pulp with a complex enzyme and glycine for enzyme treatment, and then ultrasonically treating to obtain activated pulp; S2, mixing the activated pulp with an NMMO aqueous solution, lysine, and oxidized nanocellulose to swell, and then forming the mixture through vacuum dehydration, dry-jet wet spinning, and gradient coagulation bath molding to obtain spun fibers; S3, adding the spun fibers to an aspartic acid / citric acid mixed solution, and subjecting the mixture to UV-catalyzed cross-linking treatment to obtain the regenerated cellulose fibers. The present application precisely regulates the cellulose supramolecular structure through complex enzyme-amino acid synergistic pretreatment, combines nanocellulose reinforcement with UV-catalyzed in-situ cross-linking technology, strengthens the fiber lateral binding force at the molecular level, fundamentally solves the fibrillation problem of regenerated cellulose fibers, and simultaneously has good mechanical properties, dyeing properties, and hydrophilic comfort.

Description

Technical Field

[0001] The present application relates to the technical field of regenerated cellulose fibers, and in particular, to a regenerated cellulose fiber and a preparation method thereof. Background Art

[0002] Regenerated cellulose fiber is made by extracting pure cellulose from natural cellulose-rich plants such as cotton, hemp, bamboo, shrubs, reeds, etc., then impregnating it with caustic soda, reacting chemically with carbon disulfide and alkali solution, and then reducing it to cellulose fibers with a certain degree of parallelism and crystallinity through wet spinning. Finally, it is post-processed to produce short fibers or filaments of different specifications.

[0003] Currently, the regenerated cellulose fibers commonly used in the textile and apparel market mainly include lyocell fibers, modal fibers, and bamboo pulp fibers. Compared with synthetic fibers, these fibers have excellent biodegradability, hygroscopicity, and breathability. They also have good dyeability, washability, non-deformation properties, and good elasticity, making them very popular in the market. However, when regenerated cellulose fibers and their fabrics are subjected to mechanical friction in a wet state, they are prone to fibrillation. In other words, small fibers that split axially separate from the fiber surface, causing pilling on the fabric surface, fading of color, and affecting the smooth feel of the fabric, limiting their widespread application in the textile and apparel field. Existing methods, such as cross-linking agents, blending modification, and plasma treatment, often sacrifice the mechanical properties or environmental friendliness of the fiber, and the equipment costs are relatively high. Summary of the Invention

[0004] The embodiments of the present application provide a regenerated cellulose fiber and a preparation method thereof. The cellulose supramolecular structure is precisely regulated by composite enzyme-amino acid synergistic pretreatment, and nanocellulose reinforcement and UV-catalyzed in-situ cross-linking technology are combined to strengthen the lateral binding force of the fiber at the molecular level, fundamentally solving the fibrillation problem of the regenerated cellulose fiber, while having good mechanical properties, dyeing properties and hydrophilic comfort.

[0005] In order to achieve the above objectives, in a first aspect, the present application provides the following technical solution: a method for preparing regenerated cellulose fibers, comprising the following steps:

[0006] S1. Mixing cellulose pulp with complex enzyme and glycine for enzyme treatment, and then filtering, drying and ultrasonicating to obtain activated pulp.

[0007] S2. The activated pulp is mixed with an NMMO aqueous solution, lysine, and oxidized nanocellulose to swell, and the mixture is subjected to vacuum dehydration dissolution, dry-jet wet spinning, and gradient coagulation bath molding to obtain nascent fibers.

[0008] S3. Adding the as-spun fibers to an aspartic acid / citric acid mixed solution, and subjecting the fibers to UV-catalyzed cross-linking treatment to obtain the regenerated cellulose fibers.

[0009] The complex enzyme comprises neutral endoglucanase and alkaline xylanase in a mass ratio of 3-5:1; the oxidized nanocellulose is TEMPO oxidized nanocellulose with a carboxyl content of 1.1 mmol / g-1.3 mmol / g and an aspect ratio of >100.

[0010] At present, it is generally believed that the reason why regenerated cellulose fibers are prone to fibrillation is mainly relevant to its microstructure. For example, the diameter of lyocell fiber is about 10-30 micron, which is composed of large fibrils with a diameter of about 0.5-1 micron, and the large fibrils are composed of microfibrils with a diameter of about 100 nanometers, and the basic fiber diameter of microfibrils is about 5-20 nanometers. In addition, lyocell fiber has a skin-core structure, and the epidermal order is relatively low, with a thickness of tens to hundreds of nanometers. More importantly, the special forming technology of lyocell fiber makes its structural units at all levels highly oriented, causing the molecular force in the unit to be strong, but the lateral force between the units is weaker, showing the structural characteristics of high crystallization and high orientation. Under wet state, the fiber swelling is not easy to cause the structural unit axial slippage, but after a small amount of destruction of lateral hydrogen bonds, if a mechanical friction external force is applied, separation easily occurs between the fibrils, causing fiber surface fibrillation.

[0011] The present application pretreats cellulose with a specific ratio of complex enzyme-amino acid. The complex enzyme can selectively cut the amorphous region segments of cellulose, reduce fine fibers, reduce the tendency of fibril stripping, and reduce the degree of polymerization. Glycine can bind to the active center of the complex enzyme through hydrogen bonds, significantly enhancing the efficiency and performance of the complex enzyme system. At the same time, with the assistance of ultrasonic treatment, it can destroy the microfiber aggregation bundles and reduce the formation of highly oriented structures in subsequent spinning.

[0012] In this application, nanocellulose crystals (CNC) and lysine are introduced into NMMO (methylmorpholine oxide) solution. The nano-size effect of CNC enables it to be embedded in the gaps between cellulose microfibrils, and the binding force between microfibrils is enhanced through the hydrogen bond network. The flexible long chain of lysine can fill the areas that CNC cannot cover, and through condensation to form amide bonds and ionic bonds, a three-dimensional cross-linked network of "cellulose-CNC-lysine" is constructed, which inhibits the peeling of microfibrils in the wet state and improves the mechanical properties and anti-fibrillation properties of the fiber. At the same time, the -COO on the surface of CNC - and -NH3 of lysine + In the wet state, a zwitterionic layer can be formed, which locks water molecules through electrostatic attraction and reduces the damage of water molecules to cellulose hydrogen bonds. In addition, the negatively charged surface of CNC preferentially adsorbs dye anions, while the -NH2 of lysine provides cationic sites to achieve double-site dyeing. The condensation reaction of lysine can reduce the free hydroxyl groups of cellulose, reduce the dye hydrolysis rate, and greatly improve the dyeing performance.

[0013] This application uses an aspartic acid / citric acid system to achieve green cross-linking of cellulose under UV catalysis, avoiding the toxic chemical residues of traditional cross-linking agents (such as TAHT, glutaraldehyde, etc.). The carboxyl group of aspartic acid can undergo esterification reaction with the hydroxyl group of cellulose to form a covalent bond, and citric acid, as a tricarboxylic acid, can connect multiple cellulose chains and condense with aspartic acid to form amide-ester composite cross-linking points, synergistically constructing a composite cross-linking network, enhancing the lateral bonding strength of the fibers, and the cross-linking network has moderate flexibility.

[0014] In any of the above technical solutions, further, in step S1, the added amount of the complex enzyme is 0.8%-1.0% of the dry weight of the cellulose pulp; and the added amount of the glycine is 0.7%-0.9% of the dry weight of the cellulose pulp.

[0015] In any of the above technical solutions, further, in step S1, the cellulose pulp has a degree of polymerization of 300-600 and is selected from at least one of wood pulp, cotton pulp, bamboo pulp, and straw pulp.

[0016] In any of the above technical solutions, further, in step S1, the pH of the enzyme treatment is 8-9, the temperature is 45° C.-50° C., and the reaction time is 30 min-45 min.

[0017] In any of the above technical solutions, further, in step S1, the frequency of the ultrasonic treatment is 20kHz-25kHz, the power is 250W-350W, and the time is 20min-40min.

[0018] The optimal ultrasonic treatment parameters can destroy the microfiber bundles, reduce the size of cellulose aggregates in the solution, improve the uniformity of pulp dissolution, and reduce the formation of highly oriented structures in subsequent spinning.

[0019] In any of the above technical solutions, further, in step S1, the filtered waste liquid can be ultrafiltered using a 50 kDa membrane to retain the complex enzyme and the enzyme-glycine complex, and the glycine can be recovered by electrodialysis and recycled.

[0020] In any of the above technical solutions, further, in step S2, the mass concentration of the NMMO aqueous solution is 85%-90%.

[0021] In any of the above technical solutions, further, in step S2, the amount of lysine added is 0.5%-2% of the mass of the activated pulp, and the amount of oxidized nanocellulose added is 0.5%-2% of the mass of the activated pulp.

[0022] In any of the above technical solutions, further, in step S2, the spinneret aperture of the dry-jet wet spinning is 0.08 mm to 0.12 mm, and the air section length is 80 mm to 120 mm. The gradient coagulation bath comprises: a first coagulation bath: a 15% to 25% NMMO aqueous solution at a temperature of 20°C to 30°C; and a second coagulation bath: a 3% to 8% Na2CO3 aqueous solution at a temperature of 35°C to 45°C.

[0023] The preferred gradient coagulation process achieves gradient regulation of the cortical structure through the solvent diffusion rate. The parameters of the first coagulation bath can delay the coagulation of the core layer, reduce the porosity, and create conditions for the initial densification of the cortex. The parameters of the second coagulation bath can quickly foam the core layer to form a dense cortex, reduce the fiber cross-section porosity, and improve the wet wear resistance of cellulose.

[0024] In any of the above technical solutions, further, in step S3, the aspartic acid / citric acid mixed solution contains 0.4wt%-0.6wt% of aspartic acid and 2.8wt%-3.2wt% of citric acid.

[0025] The optimal dosage of aspartic acid provides appropriate active crosslinking sites, ensuring sufficient crosslink density while maintaining molecular chain flexibility. Excessive aspartic acid dosage can lead to fiber embrittlement due to excessive amide bond formation, disrupting the hydrogen bonding network between microfibrils. Insufficient dosage reduces crosslink density, making it difficult to effectively inhibit microfibril debonding. The optimal amount of citric acid allows for precise control of the reaction system's pH and three-dimensional crosslinking structure. Excessive concentrations can easily trigger side reactions and lead to uneven crosslinking. Insufficient concentrations can disrupt the core layer's pore distribution and cause uncontrolled phase separation.

[0026] In any of the above technical solutions, further, in step S3, the wavelength of the UV is 363 nm-367 nm, and the intensity is 5 mW / cm 2 -10mW / cm 2 , the irradiation time is 3min-8min.

[0027] Compared with the prior art, the method provided in the embodiments of the present application has the following technical effects:

[0028] (1) This application uses a composite enzyme-amino acid synergistic pretreatment to precisely regulate the supramolecular structure of cellulose, combines nanocellulose filling with lysine flexible cross-linking, strengthens the lateral bonding force of fibers at the molecular level, effectively inhibits the peeling of microfibrils in a wet state, and fundamentally solves the fibrillation problem.

[0029] (2) This application improves the tensile strength of the fiber through CNC nano-reinforcement and UV-catalyzed in-situ cross-linking technology, and the cross-linked network has both rigidity and flexibility. At the same time, CNC and lysine can form a double-site dyeing structure and a zwitterionic layer, thereby improving the dye adsorption rate and maintaining the moisture absorption and breathability properties of natural fibers.

[0030] (3) The method of the present application has a simple process and is easy to realize industrial production. The raw materials are all cheap food-grade raw materials or industrial-grade preparations, which are low in cost, non-toxic and free of harmful chemical residues, and the biodegradability of cellulose is maintained throughout the process.

[0031] (4) The regenerated cellulose composite fiber prepared by the method of the present application has the characteristics of good anti-fibrillation property, high strength, good moisture absorption and breathability, etc. It can be used alone or blended with cotton, wool and other synthetic fibers for use in high-end clothing fabrics and industrial textiles.

[0032] In a second aspect, the present application also provides a regenerated cellulose fiber, which is prepared according to the above preparation method.

[0033] In a third aspect, the present application also provides the application of the above-mentioned regenerated cellulose fiber in the field of textiles.

[0034] It should be understood that both the foregoing general description and the following detailed description are for the purpose of illustration and description and are not necessarily restrictive of the present disclosure. At the same time, the description serves to explain the principles of the present disclosure. DETAILED DESCRIPTION

[0035] In order to make the technical solutions and advantages of the embodiments of the present application more clear, the exemplary embodiments of the present application are further described in detail below. Obviously, the described embodiments are only part of the embodiments of the present application, and are not an exhaustive list of all embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other unless they conflict.

[0036] The term "and / or" in this application is merely a description of the association relationship between associated objects, indicating that three relationships may exist, for example, A and / or B. Specifically, it is understood that: A and B may be included at the same time, A may exist alone, or B may exist alone, and any of the above three situations may exist.

[0037] Example 1

[0038] This embodiment provides a method for preparing regenerated cellulose fiber, specifically:

[0039] (1) Take 1 kg of cellulose pulp (wood pulp, moisture content ≤8%, degree of polymerization 550), add complex enzyme (neutral endoglucanase and alkaline xylanase = 4:1, total addition amount is 0.9% of pulp dry weight) and glycine (0.8% of pulp dry weight), beat the pulp to a moisture content of 90%, and react with mechanical stirring at 45℃, pH = 8.5 for 40 minutes until the degree of polymerization is reduced to 417. After the reaction is completed, filter through a 200 mesh screen, dry, and then ultrasonically treat (300 W, 25 kHz) for 30 minutes to obtain activated pulp; the separated filtered waste liquid is ultrafiltered with a 50 kDa membrane to retain the complex enzyme and enzyme-glycine complex, and glycine is recovered by electrodialysis.

[0040] (2) The activated pulp was mixed with an aqueous NMMO solution (mass concentration of 87%), lysine (1.5% of the dry weight of the activated pulp), and oxidized CNC (TEMPO oxidation, carboxyl content of 1.2 mmol / g, 1% of the dry weight of the pulp, aspect ratio>100) to swell, wherein the solid content of the activated pulp was 10%, and vacuum dehydration was performed at 90°C (-0.095 MPa) until it was completely dissolved to obtain a spinning solution.

[0041] (3) The spinning solution was extruded through a 0.10 mm spinneret with an air section length of 100 mm, and passed through a 20% NMMO coagulation bath (25°C, time 5 s) and a 5% Na2CO3 coagulation bath (40°C) to obtain nascent fibers.

[0042] (4) The as-spun fibers were immersed in a 0.5% aspartic acid / 3% citric acid mixed aqueous solution and irradiated with a 365 nm ultraviolet lamp (intensity 8 mW / cm 2 ), irradiated for 5 minutes, washed with water and dried to obtain regenerated cellulose fibers.

[0043] Example 2

[0044] This embodiment provides a method for preparing regenerated cellulose fiber, specifically:

[0045] (1) Take 1 kg of cellulose pulp (bamboo pulp, moisture content ≤ 8%, degree of polymerization 500), add complex enzyme (neutral endoglucanase and alkaline xylanase = 3.1, the total addition amount is 0.8% of pulp dry weight) and glycine (0.7% of pulp dry weight), beat the pulp to a moisture content of 90%, and react with mechanical stirring at 45 ° C, pH = 8 for 30 minutes until the degree of polymerization is reduced to 400. After the reaction is completed, filter through a 200 mesh sieve, dry, and then ultrasonically treat (250 W, 20 kHz) for 20 minutes to obtain activated pulp; the separated filtered waste liquid is ultrafiltered with a 50 kDa membrane to retain the complex enzyme and enzyme-glycine complex, and glycine is recovered by electrodialysis.

[0046] (2) The activated pulp was mixed with an aqueous solution of NMMO (85% by mass), lysine (0.5% by dry weight of the activated pulp), and oxidized CNC (TEMPO oxidation, carboxyl content of 1.1 mmol / g, 0.5% by dry weight of the pulp, aspect ratio>100) to swell, wherein the solid content of the activated pulp was 10%, and vacuum dehydration was performed at 90°C (-0.095 MPa) until the pulp was completely dissolved to obtain a spinning solution.

[0047] (3) The spinning solution was extruded through a 0.08 mm spinneret with an air section length of 80 mm, and passed through a 15% NMMO coagulation bath (20°C, time 5 s) and a 3% Na2CO3 coagulation bath (35°C) to obtain nascent fibers.

[0048] (4) The as-spun fibers were immersed in a mixed aqueous solution of 0.4% aspartic acid and 2.8% citric acid and irradiated with a 363 nm ultraviolet lamp (intensity 5 mW / cm 2 ), irradiated for 3 minutes, washed with water and dried to obtain regenerated cellulose fibers.

[0049] Example 3

[0050] This embodiment provides a method for preparing regenerated cellulose fiber, specifically:

[0051] (1) Take 1 kg of cellulose pulp (cotton pulp, moisture content ≤8%, degree of polymerization 600), add complex enzyme (neutral endoglucanase and alkaline xylanase = 5:1, total addition amount is 1.0% of pulp dry weight) and glycine (0.9% of pulp dry weight), beat the pulp to a moisture content of 90%, and react with mechanical stirring at 50℃, pH = 9 for 45 minutes until the degree of polymerization is reduced to 430. After the reaction is completed, filter through a 200 mesh sieve, dry, and then ultrasonically treat (350 W, 25 kHz) for 40 minutes to obtain activated pulp; the separated filtered waste liquid is ultrafiltered with a 50 kDa membrane to retain the complex enzyme and enzyme-glycine complex, and glycine is recovered by electrodialysis.

[0052] (2) The activated pulp was mixed with NMMO aqueous solution (mass concentration of 90%), lysine (2% of the dry weight of the activated pulp), and oxidized CNC (TEMPO oxidation, carboxyl content of 1.3 mmol / g, 2% of the dry weight of the pulp, aspect ratio>100) to swell, wherein the solid content of the activated pulp was 10%, and vacuum dehydration was performed at 90°C (-0.095 MPa) until it was completely dissolved to obtain a spinning solution.

[0053] (3) The spinning solution was extruded through a 0.12 mm spinneret with an air section length of 120 mm, and passed through a 25% NMMO coagulation bath (30°C, time 5 s) and an 8% Na2CO3 coagulation bath (45°C) to obtain nascent fibers.

[0054] (4) The as-spun fibers were immersed in a mixed aqueous solution of 0.6% aspartic acid and 3.2% citric acid and irradiated with a 367 nm ultraviolet lamp (intensity 10 mW / cm 2 ), irradiated for 8 minutes, washed with water and dried to obtain regenerated cellulose fibers.

[0055] Comparative Example 1

[0056] The preparation method provided in this comparative example is the same as that of Example 1 except for the following parameter settings: in step (1), the mass ratio of neutral endoglucanase to alkaline xylanase is 2:1.

[0057] Comparative Example 2

[0058] The preparation method provided in this comparative example is the same as that of Example 1 except for the following parameter settings: in step (1), the mass ratio of neutral endoglucanase to alkaline xylanase is 6:1.

[0059] Comparative Example 3

[0060] The preparation method provided in this comparative example is the same as that of Example 1 except for the following parameter settings: in step (2), lysine is replaced by an equal amount of arginine.

[0061] Comparative Example 4

[0062] The preparation method provided in this comparative example is the same as that of Example 1 except for the following parameter settings: in step (2), an equal amount of unoxidized ordinary CNC is used to replace the oxidized CNC.

[0063] Comparative Example 5

[0064] The preparation method provided in this comparative example is the same as that of Example 1 except for the following parameter settings: in step (4), the above-mentioned primary fibers are immersed in glutaraldehyde (1%), cross-linked at 60°C for 20 minutes, washed with water and dried to obtain regenerated cellulose fibers.

[0065] The properties of the regenerated cellulose fibers obtained in Examples 1-3 and Comparative Examples 1-5 were tested, and the results are shown in Table 1.

[0066] Index detection method:

[0067] Anti-fibrillation performance: The wet friction test adopts FZ / T 52019-2018 "Lyocell Staple Fiber". Under constant rotation speed, the wet friction time corresponds to the number of wet frictions. The longer the wet friction time or the more wet friction times, the stronger the anti-fibrillation ability.

[0068] Mechanical properties: Dry tensile strength / (cN / dtex) and dry elongation / (%) were measured in accordance with GB / T 14337-2022 "Test method for tensile properties of chemical staple fibers". The wet tensile strength test method is the same as the dry tensile strength test method, but the test fiber is soaked in water for 24 hours before testing.

[0069] Dyeing performance: Reactive dye (CI Reactive Red 195) was used for dyeing under the same dyeing conditions (temperature 60°C, pH = 11, time 60 min). The absorbance of the residual liquid was measured by UV spectrophotometer, and the adsorption rate of the dye on the fiber was calculated.

[0070] Moisture regain: Refer to GB / T 9994-2008 (under constant temperature and humidity conditions) to measure the moisture absorption and air permeability of the fiber.

[0071] Table 1

[0072] Wet friction / s Dry tensile strength (cN / dtex) Wet tensile strength (cN / dtex) Dry elongation / % Dyeing rate / % Moisture regain / % Example 1 25.0 5.1 3.8 13.0 96 10.5 Example 2 20.8 4.5 3.3 13.5 93 11.0 Example 3 22.5 4.8 3.5 12.5 95 10.2 Comparative Example 1 9.4 3.9 2.3 15.2 82 13.5 Comparative Example 2 10.7 4.0 2.5 14.8 85 13.0 Comparative Example 3 10.2 4.2 2.6 14.0 88 12.8 Comparative Example 4 9.3 3.6 2.0 16.5 83 14.0 Comparative Example 5 8.9 3.4 1.8 18.0 87 15.5

[0073] As can be seen from Table 1, Examples 1-3 have excellent anti-fibrillation properties and good mechanical properties, while Comparative Examples 1-5 have significantly deteriorated performance due to component adjustment; the dye uptake of Examples 1-3 is significantly higher than that of Comparative Examples 1-5, indicating that the oxidized CNC+amino acid crosslinking in the present application provides more dye binding sites; the moisture regain of Examples 1-3 is moderate, indicating that the fiber has both hydrophilicity and strength, while the moisture regain of Comparative Examples 1-5 is too high, indicating that its structure is loose, resulting in enhanced hygroscopicity but deteriorated mechanical properties.

[0074] Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present disclosure.

[0075] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0076] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for preparing regenerated cellulose fiber, characterized in that: The following steps are involved: S1, mixing cellulose pulp with a complex enzyme and glycine for enzyme treatment, and then filtering, drying, and ultrasonicating to obtain activated pulp; S2, mixing the activated pulp with an NMMO aqueous solution, lysine, and oxidized nanocellulose to swell, and performing vacuum dehydration dissolution, dry-jet wet spinning, and gradient coagulation bath molding to obtain nascent fibers; S3, adding the as-spun fiber to an aspartic acid / citric acid mixed solution, and subjecting the fiber to UV catalytic cross-linking treatment to obtain the regenerated cellulose fiber; The complex enzyme comprises neutral endoglucanase and alkaline xylanase in a mass ratio of 3-5:1; the oxidized nanocellulose is TEMPO-oxidized nanocellulose, with a carboxyl content of 1.1 mmol / g-1.3 mmol / g and an aspect ratio of >100; In step S2, the aperture of the spinneret in the dry-jet wet spinning is 0.08 mm to 0.12 mm, and the length of the air section is 80 mm to 120 mm; The gradient coagulation bath includes: a first coagulation bath: a 15%-25% NMMO aqueous solution at a temperature of 20° C.-30° C.; a second coagulation bath: a 3%-8% Na 2 CO 3 aqueous solution at a temperature of 35° C.-45° C.

2. The method for preparing regenerated cellulose fiber according to claim 1, characterized in that: In step S1, the added amount of the complex enzyme is 0.8%-1.0% of the dry weight of the cellulose pulp; the added amount of the glycine is 0.7%-0.9% of the dry weight of the cellulose pulp.

3. The method for preparing regenerated cellulose fiber according to claim 1, characterized in that: In step S1, the cellulose pulp has a degree of polymerization of 300-600 and is selected from at least one of wood pulp, cotton pulp, bamboo pulp, and straw pulp.

4. The method for preparing regenerated cellulose fiber according to claim 1, characterized in that: In step S1, the pH of the enzyme treatment is 8-9, the temperature is 45°C-50°C, and the reaction time is 30min-45min; and / or In step S1, the frequency of the ultrasonic treatment is 20 kHz-25 kHz, the power is 250 W-350 W, and the time is 20 min-40 min.

5. The method for preparing regenerated cellulose fiber according to claim 1, characterized in that: In step S2, the mass concentration of the NMMO aqueous solution is 85%-90%; and / or In step S2, the amount of lysine added is 0.5%-2% of the mass of the activated pulp, and the amount of oxidized nanocellulose added is 0.5%-2% of the mass of the activated pulp.

6. The method for preparing regenerated cellulose fiber according to claim 1, characterized in that: In step S3, the aspartic acid / citric acid mixed solution contains 0.4 wt%-0.6 wt% of aspartic acid and 2.8 wt%-3.2 wt% of citric acid.

7. The method for preparing regenerated cellulose fiber according to claim 1, characterized in that: In step S3, the wavelength of the UV is 363 nm-367 nm, the intensity is 5 mW / cm2-10 mW / cm2, and the irradiation time is 3 min-8 min.

8. A regenerated cellulose fiber, characterized in that The invention discloses a novel cellulose acetate resin composition comprising the steps of claim 1 , wherein the cellulose acetate resin composition is prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the regenerated cellulose fiber according to claim 8 in the field of textiles.