Blending modified antifibrillated lyocell fiber and preparation method thereof

Abstract

A preparation method of the blended modified antifibrillated lyocell fiber comprises three steps as follows: S1, a fibroin raw material and a cellulose raw material are dissolved in different NMMO / water mixed solvents respectively, and a fibroin solution and a cellulose solution are obtained; s2, transferring the fibroin solution and the cellulose solution into a reaction kettle, adding a modifier, vacuumizing to remove oxygen, heating to 50-85 DEG C, and stirring to react to obtain a composite spinning solution; the modifier is a small molecular compound containing an epoxy group or an oxygen-containing heterocyclic ring; s3, the composite spinning solution is extruded through a spinneret plate, fiber forming is conducted through a coagulating bath, drafting and winding are conducted, and the blending modified antifibrillated lyocell fiber is prepared. According to the invention, through in-situ modification of the lyocell fiber spinning solution, the prepared lyocell fiber has the intrinsic antifibrillation capability, the addition of an after-finishing process for treatment is not needed, meanwhile, the mechanical property of the fiber is improved, and the fiber is endowed with better skin-friendly property and wearing comfort.

Description

Technical Field

[0001] The invention relates to the technical field of chemical fiber production, in particular to a blended modified anti-fibrillation lyocell fiber and a preparation method thereof. Background Art

[0002] Lyocell fiber is a new type of regenerated cellulose fiber produced through dissolution and wet spinning using cellulose as the raw material and N-methylmorpholine-N-oxide (NMMO) as the solvent. Due to the near-100% recyclability of the NMMO solvent, it is considered the most environmentally friendly regenerated cellulose fiber. Lyocell fiber has a high degree of axial orientation, with the spaces between the microfibrils highly elongated along the fiber's axis. However, the transverse bonding between the microfibrils is weak. In the wet state, the already fragile hydrogen bonds between the fibers are replaced by water, further weakening the transverse bonding. In addition to resulting in insufficient mechanical properties, lyocell fibers and their fabrics can also experience severe fibrillation during processing, production, and use, making lyocell fabrics prone to pilling, affecting daily use.

[0003] Current technologies for addressing lyocell fiber fibrillation primarily focus on the fiber and fabric finishing stages, primarily using finishing auxiliaries containing crosslinking agents to treat lyocell fibers and fabrics to improve their fibrillation resistance. For example, patent CN 111893749A describes a composite crosslinking agent containing C2-C6 dialdehyde compounds. Lyocell fibers are immersed in a crosslinking solution and treated using a two-dip, two-pad process to produce fibrillation-resistant lyocell fibers. Forming a protective coating on the surface of lyocell fibers is also a common method for achieving fibrillation resistance. For example, patent CN 119083176A describes mixing lyocell fibers with a sodium alginate solution and forming a protective layer on the surface through a crosslinking reaction, thereby imparting fibrillation resistance and flame retardancy to the fibers. However, both of these methods require the use of a crosslinking agent during the fiber and fabric finishing process, resulting in lengthy process steps. Furthermore, both the crosslinking agent and the protective layer experience performance degradation after repeated washings. In addition, the composition of cross-linking agents is complex, traditional cross-linking agents (such as glutaraldehyde, etc.) are toxic, the reaction degree is uncontrollable, processing is difficult, the post-processing process produces a large amount of wastewater, which is difficult to treat, and there are serious pollution problems. Summary of the Invention

[0004] In order to solve the problem that lyocell fibers produced by conventional technology are not resistant to fibrillation, the present invention provides a method for preparing lyocell fibers that are resistant to fibrillation through blending and modification.

[0005] The present invention uses silk protein to perform in-situ grafting modification on cellulose. Silk protein polypeptides are linked between cellulose chains using small molecule modifiers containing epoxy groups or oxygen-containing heterocycles to prepare a silk protein / cellulose composite spinning solution. Anti-fibrillation lyocell fibers are then produced through wet spinning. The specific preparation method is as follows:

[0006] S1. Dissolving a silk protein raw material and a cellulose raw material in different NMMO / water mixed solvents to obtain a silk protein solution and a cellulose solution.

[0007] The silk protein raw material is any one of silk cocoons, silk, and waste silk, or is a silk protein powder obtained by dissolving and regenerating any one of silk cocoons, silk, and waste silk. In the NMMO / water mixed solvent used to dissolve the silk protein raw material, the mass percentage of NMMO is 75-88%, and the rest is water. The silk protein raw material is added to the NMMO / water mixed solvent, heated to 60-75°C under a vacuum environment, and stirred at a speed of 10-50r / min until completely dissolved to obtain a silk protein solution. The amount of silk protein raw material added accounts for 5-15% of the total mass of the solution.

[0008] The cellulose raw material is cellulose pulp from any one of bamboo, coniferous wood, bagasse, and cotton. The NMMO / water mixed solvent used to dissolve the cellulose raw material comprises 50-65% by weight of NMMO, with the remainder being water. The cellulose raw material is added to the NMMO / water mixed solvent, heated to 50-95°C under a vacuum environment, and stirred at a speed of 10-50 rpm until completely dissolved, to obtain a cellulose solution. The amount of cellulose raw material added accounts for 5-20% of the total mass of the solution.

[0009] S2. Transfer the silk protein solution and cellulose solution to a reactor, stir and mix them evenly, then add a modifier, vacuum and deoxygenate, heat to 50-85°C, stir at 20-100 r / min, and stir and react for 20-60 minutes to obtain a composite spinning solution.

[0010] The modifier is a small molecule compound containing an epoxy group or an oxygen-containing heterocycle.

[0011] S3. The composite spinning solution is extruded through a spinneret by wet spinning equipment, and then subjected to fiber formation in a coagulation bath, drawing and winding to obtain a blended modified anti-fibrillation lyocell fiber.

[0012] Preferably, the modifier is selected from any one of maleic anhydride, ethylene oxide, propylene oxide, and glycidyl methacrylate. Its typical molecular structure is shown in formula (a) or formula (b):

[0013]

[0014] Wherein, R and R' are independently selected from one of methyl, ethyl, propyl, butyl or a C5-C12 long chain group.

[0015] Preferably, the mass ratio of the silk protein raw material to the cellulose raw material is (20-25):(30-35), and the amount of the modifier is 0.2-10.0% of the mass of the silk protein raw material.

[0016] Preferably, step S3 specifically involves transferring the composite spinning solution to a silo of a wet spinning device, extruding the spinning solution through a spinneret, controlling the yarn speed at 30 to 100 m / min, passing through an air bath to a coagulation bath, wherein the coagulation bath is ethanol, and obtaining fiber yarn tube spinning through drawing and winding.

[0017] Compared with the prior art, the present invention is beneficial in that:

[0018] (1) The present invention solves the problem of poor inter-segment bonding ability of lyocell fibers perpendicular to the orientation direction at the molecular level by in-situ modification of the lyocell fiber spinning solution. This makes the prepared modified lyocell fibers inherently resistant to fibrillation, eliminating the need for additional post-finishing processing, shortening the production process, reducing costs, and reducing pollution. At the same time, the mechanical properties of the fibers are improved through intermolecular bonding.

[0019] (2) The present invention utilizes small molecules containing epoxy groups or oxygen-containing heterocycles as modifiers to link silk protein polypeptides between long cellulose chains through chemical bonds. The longer the chain of the selected modifier, the smaller the rigidity of the molecular chain, the better the fluidity of the obtained spinning solution, and the lower the viscosity. Therefore, the viscosity of the spinning solution can be effectively regulated by optimizing the chain length of the modifier, which is beneficial to the processing of lyocell fibers.

[0020] (3) Blending silk protein with cellulose to prepare composite fibers can give the fibers better skin-friendliness and wearing comfort, and can also give the cellulose material some of the functions of silk.

[0021] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a reaction mechanism diagram of the blended modified anti-fibrillation lyocell fiber of the present invention.

[0023] Figure 2 It is a schematic structural diagram of the blended modified anti-fibrillation lyocell fiber of the present invention. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0025] Example 1

[0026] 20 g of mulberry silkworm cocoons from which impurities had been removed were cut into 5 mm pieces with scissors, and a mixed solvent of N-methylmorpholine oxide (NMMO) and water with a mass ratio of 85 / 15 was prepared. The cocoon fragments were added to 180 g of the mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.08 to -0.1 MPa, heated to 75°C, and stirred until the cocoon fragments were completely dissolved to obtain a silk protein solution.

[0027] A 50 / 50 mass ratio NMMO / water mixed solvent was prepared, 35 g of wood pulp was weighed and added to 525 g of the mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.08 to -0.1 MPa, heated to 95°C, and stirred until the wood pulp was completely dissolved to obtain a cellulose solution.

[0028] The silk protein solution and the cellulose solution were transferred to a corrosion-resistant stainless steel bottle and stirred to mix evenly. Then, 0.4 g of the modifier maleic anhydride was added to the reaction system. The vacuum degree in the bottle was evacuated to -0.085 MPa by using a water circulation vacuum pump through a through-hole connected to the closed pressure-resistant and corrosion-resistant stainless steel bottle. The mixed solution in the bottle was then heated to 80°C and stirred at a speed of 20 r / min for 30 minutes. After the reaction was completed, a silk / cellulose modified composite spinning solution was obtained.

[0029] The blended modified anti-fibrillated lyocell fiber is prepared by wet spinning equipment: the composite spinning solution is transferred to the hopper of the wet spinning equipment, and the spinning solution is extruded through the spinneret, the yarn speed is controlled at 30m / min, and the yarn is passed through an air bath to a coagulation bath, the coagulation bath is ethanol, and the fiber yarn is obtained by winding.

[0030] Example 2

[0031] A mixed solvent of N-methylmorpholine oxide (NMMO) / water with a mass ratio of 82 / 18 was prepared, 25 g of silk protein powder with a particle size of 15 μm was added to 225 g of the mixed solvent and transferred to a pressure-resistant sealed reactor, the reactor was evacuated to -0.08 to -0.1 MPa, and heated to 75°C, stirred and dissolved to obtain a silk protein solution.

[0032] A NMMO / water mixed solvent with a mass ratio of 50 / 50 was prepared, 35 g of wood pulp was weighed and added to 525 g of the mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.08 to -0.1 MPa, heated to 95°C, and stirred until the wood pulp was completely dissolved to obtain a cellulose solution.

[0033] The silk protein solution and the cellulose solution were transferred to a corrosion-resistant stainless steel bottle and stirred to mix evenly. Then, 0.6 g of the modifier propylene oxide was added to the reaction system. The vacuum degree in the bottle was evacuated to -0.09 MPa by using a water circulation vacuum pump through a through-hole connected to the closed pressure-resistant and corrosion-resistant stainless steel bottle. The mixed solution in the bottle was then heated to 85°C and stirred at a speed of 50 r / min for 30 minutes. After the reaction was completed, a silk / cellulose modified composite spinning solution was obtained.

[0034] The blended modified anti-fibrillated lyocell fiber is prepared by wet spinning equipment: the composite spinning solution is transferred to the hopper of the wet spinning equipment, and the spinning solution is extruded through the spinneret, the yarn speed is controlled at 30m / min, and the yarn is passed through an air bath to a coagulation bath, the coagulation bath is ethanol, and the fiber yarn is obtained by winding.

[0035] Example 3

[0036] A mixed solvent of N-methylmorpholine oxide (NMMO) / water with a mass ratio of 80 / 20 was prepared, 20 g of silk protein powder with a particle size of 10 μm was added to 230 g of the mixed solvent and transferred to a pressure-resistant sealed reactor, the reactor was evacuated to -0.1 MPa, and heated to 65°C, stirred and dissolved to obtain a silk protein solution.

[0037] A NMMO / water mixed solvent with a mass ratio of 50 / 50 was prepared, 30 g of wood pulp was weighed and added to 450 g of the mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.1 MPa, heated to 95°C, and stirred until the wood pulp was completely dissolved to obtain a cellulose solution.

[0038] The silk protein solution and the cellulose solution were transferred to a corrosion-resistant stainless steel bottle and stirred to mix evenly. Then, 0.8 g of ethylene oxide as a modifier was added to the reaction system. The vacuum degree in the bottle was evacuated to -0.09 MPa by using a water circulation vacuum pump through a through-hole connected to the closed pressure-resistant and corrosion-resistant stainless steel bottle. Nitrogen was introduced to restore the pressure in the bottle to normal pressure. Then, the mixed solution in the bottle was heated to 90°C and stirred at a speed of 30 r / min for 30 minutes. After the reaction was completed, a silk / cellulose modified composite spinning solution was obtained.

[0039] The blended modified anti-fibrillated lyocell fiber is prepared by wet spinning equipment: the composite spinning solution is transferred to the hopper of the wet spinning equipment, and the spinning solution is extruded through the spinneret, the yarn speed is controlled at 30m / min, and the yarn is passed through an air bath to a coagulation bath, the coagulation bath is ethanol, and the fiber yarn is obtained by winding.

[0040] Example 4

[0041] A mixed solvent of N-methylmorpholine oxide (NMMO) / water with a mass ratio of 86 / 14 was prepared, 20 g of silk staple fibers from which impurities had been removed were added to 220 g of the mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.1 MPa, heated to 75°C, stirred and dissolved to obtain a silk protein solution.

[0042] A NMMO / water mixed solvent with a mass ratio of 50 / 50 was prepared, 30 g of wood pulp was weighed and added to 450 g of the mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.1 MPa, heated to 95°C, and stirred until the wood pulp was completely dissolved to obtain a cellulose solution.

[0043] The silk protein solution and the cellulose solution were transferred to a corrosion-resistant stainless steel bottle and stirred to mix evenly. Then, 0.4 g of glycidyl methacrylate as a modifier was added to the reaction system. The vacuum degree in the bottle was evacuated to -0.09 MPa by using a water circulation vacuum pump through a through-hole connected to the closed pressure-resistant and corrosion-resistant stainless steel bottle. Nitrogen was introduced to restore the pressure in the bottle to normal pressure. Then, the mixed solution in the bottle was heated to 90°C and stirred at a speed of 100 r / min for 40 minutes. After the reaction was completed, a silk / cellulose modified composite spinning solution was obtained.

[0044] The blended modified anti-fibrillated lyocell fiber is prepared by wet spinning equipment: the composite spinning solution is transferred to the hopper of the wet spinning equipment, and the spinning solution is extruded through the spinneret, the yarn speed is controlled at 30m / min, and the yarn is passed through an air bath to a coagulation bath, the coagulation bath is ethanol, and the fiber yarn is obtained by winding.

[0045] The preparation reaction mechanism of the blended modified anti-fibrillation lyocell fiber of the present invention is as follows: Figure 1 As shown, n is the degree of polymerization of cellulose, ranging from 450 to 650, and m is the degree of polymerization of silk protein polypeptide, ranging from 5 to 100. The epoxy group in the modifier or the CO bond in the oxygen-containing heterocycle is broken, and is grafted simultaneously with the amino group (-NH2), carboxyl group (-COOH) on the silk protein polypeptide and the hydroxyl group (-OH) on the cellulose chain segment. The silk protein polypeptide acts as a support and link to form a strong binding effect between the cellulose molecular chains, which makes up for the binding ability between the segments of the lyocell fiber perpendicular to the orientation direction. The microstructure of the prepared blended modified anti-fibrillated lyocell fiber is shown in the figure below. Figure 2As shown. The fibrillation of Lyocell fiber stems from the fact that its highly oriented cellulose microfibrils are easily peeled longitudinally in a wet state. The introduced silk protein peptide molecules can penetrate and anchor in the lateral interface region of adjacent cellulose microfibrils. The active functional groups on the peptide chain (-NH2, -COOH and -OH, etc.) form strong physical bonds with the hydroxyl groups on the surface of the cellulose microfibrils, forming an effective "molecular bridge" and cross-linked network between the microfibrils. This significant enhancement of the lateral interface bonding effect greatly improves the ability of the microfibrils to resist water molecule penetration and shear damage, effectively locking the microfibril structure and inhibiting the occurrence and development of fibrillation.

[0046] Comparative Example 1

[0047] 20 g of silk staple fibers from which impurities had been removed were dissolved in 220 g of a mixed solvent of N-methylmorpholine oxide (NMMO) and water with a mass ratio of 86 / 14 and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.1 MPa and heated to 75°C with stirring to dissolve to obtain a silk protein solution.

[0048] 30 g of wood pulp was weighed and added to 450 g of a 50 / 50 NMMO / water mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.1 MPa and heated to 95°C and stirred until the wood pulp was completely dissolved to obtain a cellulose solution.

[0049] The silk protein solution and the cellulose solution are mixed to obtain a silk / cellulose blend spinning solution.

[0050] The silk / cellulose blend spinning solution is transferred to the hopper of the wet spinning equipment, and the spinning solution is extruded through the spinneret. The yarn speed is controlled at 30m / min, and then passed through an air bath to a coagulation bath, which is ethanol. The fiber yarn is then wound into a tube.

[0051] Comparative Example 2

[0052] 30 g of wood pulp was weighed and added to 450 g of a 50 / 50 NMMO / water mixed solvent and transferred to a pressure-resistant sealed reactor. The reactor was evacuated to -0.1 MPa and heated to 95°C and stirred until the wood pulp was completely dissolved to obtain a cellulose spinning solution.

[0053] The cellulose spinning solution is transferred to the silo of the wet spinning equipment, and the spinning solution is extruded through the spinneret. The yarn speed is controlled at 30m / min, and the yarn is passed through an air bath to a coagulation bath, which is ethanol. The fiber yarn is then wound into a tube.

[0054] The fibers prepared in Examples 1-4 and Comparative Examples 1 and 2 and the corresponding fabrics were subjected to performance tests. The results are shown in Table 1.

[0055] Table 1 Performance indicators of fibers prepared in Examples 1-4 and Comparative Examples 1 and 2

[0056]

[0057] As can be seen from the table, compared with traditional preparation methods, the mechanical properties of the blended, modified, and anti-fibrillation lyocell fibers produced by the present invention are significantly superior to those produced by conventional methods. The resulting fabrics also exhibit significantly better anti-fibrillation properties and skin-friendliness than those produced by conventional methods. Furthermore, the introduction of silk protein into the molecular structure of the present lyocell fibers also imparts bioactivity to the composite fibers, suggesting potential applications in the medical field.

[0058] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a blended modified anti-fibrillation lyocell fiber, characterized in that: The following steps are involved: S1, dissolving a silk protein raw material and a cellulose raw material in different NMMO / water mixed solvents to obtain a silk protein solution and a cellulose solution; S2. Transfer the silk protein solution and the cellulose solution to a reactor, stir and mix them evenly, then add a modifier, vacuum and deoxygenate, heat to 50-85° C., and stir and react for 20-60 minutes to obtain a composite spinning solution; the modifier is a small molecule compound containing an epoxy group or an oxygen-containing heterocycle; S3. The composite spinning solution is extruded through a spinneret by wet spinning equipment, and then subjected to fiber formation in a coagulation bath, drawing and winding to obtain a blended modified anti-fibrillation lyocell fiber.

2. The method for preparing the blended modified anti-fibrillation lyocell fiber according to claim 1, wherein: The modifier is selected from any one of maleic anhydride, ethylene oxide, propylene oxide, and glycidyl methacrylate.

3. The preparation method of the blended modified anti-fibrillation lyocell fiber according to claim 1, wherein The modifier has one of the following two molecular structural formulas: Wherein, R and R' are independently selected from one of methyl, ethyl, propyl, butyl or a C5-C12 long chain group.

4. The preparation method of the blended modified anti-fibrillation lyocell fiber according to claim 1, wherein: In step S1, the silk protein raw material is any one of silk cocoons, silk, and waste silk, or is silk protein powder obtained by dissolving and regenerating any one of silk cocoons, silk, and waste silk.

5. The method for preparing the blended modified anti-fibrillation lyocell fiber according to claim 4, wherein: In step S1, the NMMO / water mixed solvent used to dissolve the silk protein raw material has a mass percentage of NMMO of 75-88% and the rest is water; the temperature is raised to 60-75° C. under a vacuum environment for dissolution.

6. The method for preparing the blended modified anti-fibrillation lyocell fiber according to claim 1, wherein: In step S1, the cellulose raw material is cellulose pulp of any one of bamboo, softwood, bagasse and cotton.

7. The method for preparing the blended modified anti-fibrillation lyocell fiber according to claim 6, wherein: In step S1, the cellulose raw material is dissolved in an NMMO / water mixed solvent, wherein the mass percentage of NMMO is 50-65% and the rest is water; the temperature is raised to 50-95° C. under a vacuum environment for dissolution.

8. The method for preparing the blended modified anti-fibrillation lyocell fiber according to claim 1, wherein: The mass ratio of the silk protein raw material to the cellulose raw material is (20-25):(30-35), and the amount of the modifier is 0.2-10.0% of the mass of the silk protein raw material.

9. The method for preparing the blended modified anti-fibrillation lyocell fiber according to claim 1, wherein: Step S3 specifically involves transferring the composite spinning solution to the hopper of the wet spinning equipment, extruding the spinning solution through a spinneret, controlling the yarn speed at 30 m / min, passing through an air bath to a coagulation bath, wherein the coagulation bath is ethanol, and obtaining fiber yarn tube spinning through drawing and winding.

10. A fibrillation-resistant lyocell fiber, characterized in that: The method is prepared according to any one of claims 1 to 9.

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