Vitamin e-loaded lyocell fibers and a method for their production

Abstract

The application relates to the technical field of regenerated cellulose fiber materials, and particularly discloses a lyocell fiber loaded with vitamin E and a preparation method thereof.A preparation method of the lyocell fiber loaded with vitamin E comprises the following steps: nanocrystalline cellulose is added into an amino silane coupling agent solution to perform amine modification, so that amine-modified nanocrystalline cellulose is obtained; vitamin E succinate is activated to form an activated ester, and then the activated ester is mixed with the amine-modified nanocrystalline cellulose to perform amidation reaction, so that nanocrystalline cellulose loaded with vitamin E is obtained after freeze-drying; and the nanocrystalline cellulose loaded with vitamin E is mixed with lyocell spinning solution to perform spinning and shaping, so that the lyocell fiber loaded with vitamin E is obtained.The lyocell fiber loaded with vitamin E has high vitamin E loading capacity and loading stability, vitamin E release is more controllable, long-term and durable effects can be maintained, and the lyocell fiber loaded with vitamin E has excellent mechanical properties, softness and comfort, antibacterial property and ultraviolet absorption and other multifunctional properties.

Description

Technical Field

[0001] This application relates to the field of regenerated cellulose fiber materials technology, and more specifically, it relates to a vitamin E-loaded lyocell fiber and a method for preparing the same. Background Technology

[0002] As living standards improve and health awareness increases, consumers have higher and higher requirements for the functionality of textiles. In addition to basic properties such as warmth and comfort, multifunctionality such as antibacterial, skin care, and health care has become the core demand of consumers, driving the textile industry to focus on the research and development of functional fibers.

[0003] Vitamin E, as a natural antioxidant, has moisturizing, skin barrier repair, and anti-aging effects. Combining it with the excellent moisture absorption, breathability, softness, and comfort of lyocell fiber can produce textile raw materials that combine skin care and comfort, possessing significant market value. However, its fat solubility and poor compatibility with fiber processing have become a current technological bottleneck. Existing technologies typically employ microencapsulation technology to prepare vitamin E-loaded lyocell fibers. However, the inventors have discovered numerous problems with this encapsulation method in practical applications.

[0004] First, the microcapsule preparation process has stringent requirements for parameters such as temperature, pH value, and stirring rate. Even slight fluctuations can lead to uneven wall thickness and loose structure, causing premature leakage of vitamin E during storage or use, significantly reducing the fiber's efficacy and durability. Second, the bonding stability between vitamin E-encapsulated microcapsules and lyocell fibers prepared using existing technologies is insufficient. During fiber spinning, dyeing, and finishing processes, these microcapsules are easily ruptured by mechanical forces and chemical reagents, resulting in significant vitamin E loss and affecting the fiber's physical properties and appearance. Third, the release of vitamin E from microcapsules lacks controllability, failing to match the actual needs of human skin. This can easily lead to excessive or insufficient release, hindering the full realization of vitamin E's skincare and health benefits. Furthermore, the addition of microcapsules may also disrupt the excellent moisture absorption and breathability properties of lyocell fibers, reducing the comfort of the textile and limiting the further development and widespread application of vitamin E-loaded lyocell fibers. Summary of the Invention

[0005] In order to improve the vitamin E loading capacity, loading stability and efficacy persistence of lyocell fiber, and to enhance the overall performance of vitamin E-loaded lyocell fiber, this application provides a vitamin E-loaded lyocell fiber and its preparation method.

[0006] In a first aspect, this application provides a method for preparing vitamin E-loaded lyocell fiber, employing the following technical solution:

[0007] A method for preparing vitamin E-loaded lyocell fiber includes the following steps:

[0008] S1: Nanocrystalline cellulose is added to an aminosilane coupling agent solution for amination modification to obtain amination-modified nanocrystalline cellulose;

[0009] S2: Vitamin E succinate is activated to form an activated ester solution, then amino-modified nanocrystalline cellulose is added and mixed to carry out an amidation reaction. After freeze-drying, vitamin E loaded on nanocrystalline cellulose is obtained.

[0010] S3: Add vitamin E-loaded nanocrystalline cellulose to lyocell spinning solution at a ratio of 5-10 wt% to obtain mixed spinning solution, and spin to form vitamin E-loaded lyocell fibers.

[0011] By adopting the above technical solution, bamboo pulp is acid-hydrolyzed to prepare nanocrystalline cellulose to replace the organic polymer carrier. Utilizing the high specific surface area and surface modifiability of nanocrystalline cellulose, it is covalently anchored by reacting with the carboxyl groups of activated vitamin E succinate after amination to form amide bonds. This transforms fat-soluble vitamin E into a water-soluble complex, achieving stable loading of vitamin E on nanocrystalline cellulose. Furthermore, nanocrystalline cellulose and lyocell fiber are homologous, and their dispersion uniformity in NMMO solvent is ≥95%, breaking through the compatibility bottleneck of traditional physical mixing and overcoming the problem of traditional microcapsule agglomeration clogging the spinning pores.

[0012] Vitamin E can be stably loaded onto lyocell fibers through the loading of nanocrystalline cellulose, which significantly improves the loading capacity and stability of vitamin E on lyocell fibers, ensuring the long-lasting efficacy of vitamin E while retaining the excellent moisture absorption, breathability, softness and comfort of lyocell fibers.

[0013] Optionally, the amino group density of the amino-modified nanocrystalline cellulose is ≥1.2 mmol / g.

[0014] By adopting the above technical solution, the high-amine-density amino-based nanocrystalline cellulose can provide sufficient amino sites to undergo amidation reactions with the carboxyl groups of activated vitamin E succinate, ensuring the formation of more amide bonds, increasing the vitamin E loading capacity of nanocrystalline cellulose as a carrier, and thus increasing the vitamin E loading capacity of lyocell fiber.

[0015] Optionally, the mass ratio of the amino-modified nanocrystalline cellulose to the vitamin E succinate in step S2 is 1:(0.5-1.5).

[0016] By adopting the above technical solution, at this mass ratio, it is possible to ensure that vitamin E activated esters and amino-modified nanocrystalline cellulose react fully, reduce the residue of free vitamin E activated esters, and increase the vitamin E loading capacity, so that the vitamin E loading capacity of nanocrystalline cellulose reaches 220-250mg / g. This can effectively prevent the waste or deficiency of vitamin E caused by excessive vitamin E, and ensure the full exertion of skin care efficacy.

[0017] Optionally, the specific method for activating vitamin E succinate to form activated ester in step S2 is as follows: dissolve vitamin E succinate in PBS buffer to prepare VE-SE solution, then add EDC and NHS in a molar ratio of (3.5-4.5):1, stir and activate for 20-30 minutes to obtain the ester.

[0018] By adopting the above technical solution, the PBS buffer maintains pH stability, and EDC and NHS can selectively activate the carboxyl group of vitamin E succinate, enhance its reactivity with the amino group of amino-modified nanocrystalline cellulose, promote the efficient formation of amide bonds, improve the stability of activated esters, and lay the foundation for subsequent amidation reactions.

[0019] Optionally, the method for preparing the Lyocell spinning solution includes the following steps:

[0020] Add the pulp to water, adjust the pH to 4-6, add cellulase to activate it, and then adjust the pH to 9-13 to stop the activation to obtain pulp porridge.

[0021] The porridge is pressed and dehydrated to obtain hydrated cellulose with a water content of 40-60 wt%.

[0022] Aqueous cellulose is dissolved in a 50-88wt% N-methylmorpholine-N-oxide aqueous solution to obtain a lyocell spinning solution, wherein the lyocell fiber content is 8-12wt%.

[0023] Optionally, in step S3, a dry-jet wet spinning process is used for spinning and forming.

[0024] By adopting the above technical solution, in the dry-jet wet spinning process, the spinning solution first passes through an air layer and then enters the coagulation bath. The spinning process is gentle, which effectively reduces the damage and loss of vitamin E loaded on nanocrystalline cellulose by mechanical force, and at the same time reduces the impact of chemical reagents on vitamin E, ensuring the preservation of its antioxidant, ultraviolet absorption and other functional properties.

[0025] In addition, the dry-jet wet spinning process can make the fiber formation more uniform, and the spinning solution formed by the blending of vitamin E-loaded nanocrystalline cellulose and lyocell can give full play to the advantages of nanocrystalline cellulose in enhancing fiber density and improve the mechanical properties of lyocell fiber.

[0026] Optionally, the spinning parameters of the dry-jet wet spinning process are as follows: spinning speed is 50-100 m / min, the diameter of the mixed spinning solution through the spinneret is 0.04-0.08 mm, the spinning air gap is 20-40 mm, the spinning air humidity is 60-80%, and the coagulation bath concentration is 10-20%.

[0027] Secondly, this application provides a vitamin E-loaded lyocell fiber, which is prepared by a method for preparing vitamin E-loaded lyocell fiber according to this application.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. This application achieves effective loading of vitamin E by aminoating nanocrystalline cellulose and forming amide bonds with vitamin E succinate. Then, by utilizing the homology between nanocrystalline cellulose and lyocell fiber, the compatibility bottleneck of physical mixing in traditional processes is overcome, significantly improving the vitamin E loading capacity and loading stability of lyocell fiber. Combined with the barrier effect of nanocrystalline cellulose, the slow release of vitamin E is achieved, prolonging the duration of the skin care and health benefits of the fiber.

[0030] 2. This application uses a dry-jet wet spinning process to spin the fiber. The spinning solution first passes through an air layer and then enters the coagulation bath. The process is gentle and effectively reduces the loss of vitamin E caused by mechanical force damaging the vitamin E loaded on the nanocrystalline cellulose. At the same time, it reduces the impact of chemical reagents on vitamin E and ensures the antioxidant and ultraviolet absorption properties of vitamin E.

[0031] 3. In this application, nanocrystalline cellulose is used as a carrier for vitamin E, which can be uniformly dispersed in lyocell spinning solution. This not only significantly improves the effective loading capacity and loading stability of vitamin E in lyocell fiber, but also enhances the fiber density, inhibits the formation and expansion of micropores inside the fiber, and significantly improves the mechanical properties of lyocell fiber. Detailed Implementation

[0032] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0033] Example 1

[0034] A method for preparing vitamin E-loaded lyocell fiber includes the following steps:

[0035] S1: Preparation and Modification of Nanocrystalline Cellulose

[0036] (1) After crushing bamboo pulp with a degree of polymerization of 500, add it to 64wt% H2SO4 solution at a solid-liquid ratio of 1:15. Stir and react in a constant temperature water bath at 45℃ for 60 min to hydrolyze the cellulose in the amorphous region, while retaining the nanorod structure in the crystalline region. After filtration, dialyze the precipitate through deionized water to pH 6 to obtain nanocrystalline cellulose.

[0037] (2) Nanocrystalline cellulose was added to a 3wt% 3-aminopropyltriethoxysilane ethanol solution at a material-to-liquid ratio of 1:20. The mixture was stirred in a constant temperature water bath at 60℃ for 4 hours to carry out amination modification. After washing three times by centrifugation at 8000rpm / 15min, the mixture was dried to obtain amination-modified nanocrystalline cellulose with an amino group density ≥1.2mmol / g and a Zeta potential of +35mV (pH=7.0).

[0038] S2: Vitamin E anchoring

[0039] (1) Dissolve vitamin E succinate in 0.1 mol / L PBS buffer at pH 6.5 to prepare a VE-SE solution with a concentration of 30 mg / mL. Then add EDC and NHS at a molar ratio of 4.2:1. The amount of EDC and NHS added is 15 wt% of the mass of vitamin E succinate. Stir and activate for 20 min to obtain an activated ester solution.

[0040] (2) Add amino-modified nanocrystalline cellulose to the activated ester solution and mix, wherein the mass ratio of amino-modified nanocrystalline cellulose to vitamin E succinate is 1:1.1. The amidation reaction is carried out by stirring in a constant temperature water bath at 25℃ for 12h. After filtration, freeze-dry at -50℃ and 0.1mbar to obtain light yellow nanocrystalline cellulose loaded with vitamin E. The drug loading of nanocrystalline cellulose is 220-250mg / g.

[0041] S3: Dry-jet wet spinning forming

[0042] (1) Add wood pulp with a degree of polymerization of 800 to water, adjust the pH to 6, add cellulase to activate for 1 hour, and then add sodium hydroxide to adjust the pH to 10.5 to terminate the activation and obtain pulp porridge. The cellulase is liquid cellulase, which can be the product name CelluPract®AL70 provided by the supplier BIOPRACT, with the product number IPL 5B06610.

[0043] The porridge was vacuum pressed and dehydrated to obtain hydrated cellulose with a water content of 48wt%, which was then crushed into 3cm×3cm particles.

[0044] The pulverized hydrated cellulose was added to a 62wt% N-methylmorpholine-N-oxide aqueous solution at a material-to-liquid ratio of 1:4. After pre-dissolving at 70℃, the solution was dissolved in a dissolving machine under a vacuum of 4 kPa to obtain a lyocell spinning solution containing 10.6wt% lyocell fiber.

[0045] (2) Add 5 wt% of vitamin E loaded on nanocrystalline cellulose to lyocell spinning solution and disperse it by ultrasonication at 40 kHz for 30 min to obtain mixed spinning solution. The mixed spinning solution is shaped by dry-jet wet spinning at a spinning speed of 50 m / min. The spinneret aperture of the mixed spinning solution is 0.06 mm, the spinning air gap is 25 mm, the spinning air humidity is 70%, the coagulation bath concentration is 18% NMMO aqueous solution, and the coagulation bath temperature is 25 ℃. After three-stage countercurrent water washing, bleaching, and oiling, it is relaxed and dried at 80 ℃ and cut to form short fibers to obtain vitamin E loaded lyocell fibers.

[0046] Example 2

[0047] A method for preparing vitamin E-loaded lyocell fiber includes the following steps:

[0048] S1: Preparation and Modification of Nanocrystalline Cellulose

[0049] (1) After crushing bamboo pulp with a degree of polymerization of 500, add it to 64wt% H2SO4 solution at a solid-liquid ratio of 1:15. Stir and react in a constant temperature water bath at 45℃ for 60 min to hydrolyze the cellulose in the amorphous region, while retaining the nanorod structure in the crystalline region. After filtration, dialyze the precipitate through deionized water to pH 6 to obtain nanocrystalline cellulose.

[0050] (2) Nanocrystalline cellulose was added to a 3wt% 3-aminopropyltriethoxysilane ethanol solution at a material-to-liquid ratio of 1:20. The mixture was stirred in a constant temperature water bath at 60℃ for 4 hours to carry out amination modification. After washing three times by centrifugation at 8000rpm / 15min, the mixture was dried to obtain amination-modified nanocrystalline cellulose with an amino group density ≥1.2mmol / g and a Zeta potential of +35mV (pH=7.0).

[0051] S2: Vitamin E anchoring

[0052] (1) Dissolve vitamin E succinate in 0.1 mol / L PBS buffer at pH=6.5 to prepare a VE-SE solution with a concentration of 30 mg / mL. Then add EDC and NHS in a molar ratio of 3.5:1. The amount of EDC and NHS added is 15 wt% of the mass of vitamin E succinate. Stir and activate for 30 min to obtain an activated ester solution.

[0053] (2) Add amino-modified nanocrystalline cellulose to the activated ester solution and mix, wherein the mass ratio of amino-modified nanocrystalline cellulose to vitamin E succinate is 1:1.5. The mixture is stirred in a constant temperature water bath at 25°C for 12 hours to carry out the amidation reaction. After filtration, the mixture is freeze-dried at -50°C and 0.1 mbar to obtain light yellow nanocrystalline cellulose loaded with vitamin E. The drug loading of the nanocrystalline cellulose is 220-250 mg / g.

[0054] S3: Dry-jet wet spinning forming

[0055] (1) Add wood pulp with a degree of polymerization of 800 to water, adjust the pH to 5, add cellulase to activate for 1 hour, and then add sodium hydroxide to adjust the pH to 9 to terminate the activation and obtain pulp porridge.

[0056] The porridge was vacuum pressed and dehydrated to obtain hydrated cellulose with a water content of 40wt%, which was then crushed into 3cm×3cm particles.

[0057] The pulverized hydrated cellulose was added to a 50wt% N-methylmorpholine-N-oxide aqueous solution at a material-to-liquid ratio of 1:4. After pre-dissolving at 70℃, the solution was dissolved in a dissolving machine under a vacuum of 4 kPa to obtain a lyocell spinning solution containing 8wt% lyocell fiber.

[0058] (2) Add 5 wt% of vitamin E loaded on nanocrystalline cellulose to lyocell spinning solution and disperse it by ultrasonication at 40 kHz for 30 min to obtain mixed spinning solution. The mixed spinning solution is shaped by dry-jet wet spinning at a spinning speed of 100 m / min. The spinneret aperture of the mixed spinning solution is 0.04 mm, the spinning air gap is 20 mm, the spinning air humidity is 60%, the coagulation bath concentration is 10% NMMO aqueous solution, and the coagulation bath temperature is 25 ℃. After three-stage countercurrent water washing, bleaching, and oiling, it is relaxed and dried at 80 ℃ and cut to form short fibers to obtain vitamin E loaded lyocell fibers.

[0059] Example 3

[0060] A method for preparing vitamin E-loaded lyocell fiber includes the following steps:

[0061] S1: Preparation and Modification of Nanocrystalline Cellulose

[0062] (1) After crushing bamboo pulp with a degree of polymerization of 500, add it to 64wt% H2SO4 solution at a solid-liquid ratio of 1:15. Stir and react in a constant temperature water bath at 45℃ for 60 min to hydrolyze the cellulose in the amorphous region, while retaining the nanorod structure in the crystalline region. After filtration, dialyze the precipitate through deionized water to pH 6 to obtain nanocrystalline cellulose.

[0063] (2) Nanocrystalline cellulose was added to a 3wt% 3-aminopropyltriethoxysilane ethanol solution at a material-to-liquid ratio of 1:20. The mixture was stirred in a constant temperature water bath at 60℃ for 4 hours to carry out amination modification. After washing three times by centrifugation at 8000rpm / 15min, the mixture was dried to obtain amination-modified nanocrystalline cellulose with an amino group density ≥1.2mmol / g and a Zeta potential of +35mV (pH=7.0).

[0064] S2: Vitamin E anchoring

[0065] (1) Dissolve vitamin E succinate in 0.1 mol / L PBS buffer at pH=6.5 to prepare a VE-SE solution with a concentration of 30 mg / mL. Then add EDC and NHS in a molar ratio of 4.5:1. The amount of EDC and NHS added is 15 wt% of the mass of vitamin E succinate. Stir and activate for 25 min to obtain an activated ester solution.

[0066] (2) Add amino-modified nanocrystalline cellulose to the activated ester solution and mix, wherein the mass ratio of amino-modified nanocrystalline cellulose to vitamin E succinate is 1:0.5. The mixture is stirred in a constant temperature water bath at 25°C for 12 hours to carry out the amidation reaction. After filtration, it is freeze-dried at -50°C and 0.1 mbar to obtain light yellow nanocrystalline cellulose loaded with vitamin E. The drug loading of the nanocrystalline cellulose is 220-250 mg / g.

[0067] S3: Dry-jet wet spinning forming

[0068] (1) Add wood pulp with a degree of polymerization of 800 to water, adjust the pH to 4, add cellulase to activate for 1 hour, and then add sodium hydroxide to adjust the pH to 13 to terminate the activation and obtain pulp porridge.

[0069] The porridge was vacuum pressed and dehydrated to obtain hydrated cellulose with a water content of 60wt%, which was then crushed into 3cm×3cm particles.

[0070] The pulverized hydrated cellulose was added to an 88wt% N-methylmorpholine-N-oxide aqueous solution at a material-to-liquid ratio of 1:4. After pre-dissolving at 70℃, the solution was dissolved in a dissolving machine under a vacuum of 4 kPa to obtain a lyocell spinning solution containing 12wt% lyocell fiber.

[0071] (2) Add 5 wt% of vitamin E loaded on nanocrystalline cellulose to lyocell spinning solution and disperse it by ultrasonication at 40 kHz for 30 min to obtain mixed spinning solution. The mixed spinning solution is formed by dry-jet wet spinning at a spinning speed of 50 m / min. The spinneret aperture of the mixed spinning solution is 0.08 mm, the spinning air gap is 40 mm, the spinning air humidity is 80%, the coagulation bath concentration is 20% NMMO aqueous solution, and the coagulation bath temperature is 25 ℃. After three-stage countercurrent water washing, bleaching, and oiling, it is relaxed and dried at 80 ℃ and cut to form short fibers to obtain vitamin E loaded lyocell fibers.

[0072] Example 4

[0073] A vitamin E-loaded lyocell fiber is prepared in a manner that differs from that of Example 1 in that the proportion of vitamin E-loaded nanocrystalline cellulose added to the lyocell spinning solution in step S3 is 6 wt%, while the steps are the same as those in Example 1.

[0074] Example 5

[0075] A vitamin E-loaded lyocell fiber is prepared in a manner that differs from that of Example 1 in that the proportion of vitamin E-loaded nanocrystalline cellulose added to the lyocell spinning solution in step S3 is 8 wt%, while the steps are the same as those in Example 1.

[0076] Example 6

[0077] A vitamin E-loaded lyocell fiber is prepared in a manner that differs from that of Example 1 in that the proportion of vitamin E-loaded nanocrystalline cellulose added to the lyocell spinning solution in step S3 is 10 wt%, while the steps are the same as those in Example 1.

[0078] Comparative Example 1

[0079] A vitamin E-loaded lyocell fiber is prepared in a manner that differs from that of Example 1 in that the proportion of vitamin E-loaded nanocrystalline cellulose added to the lyocell spinning solution in step S3 is 4 wt%, while the steps are the same as those in Example 1.

[0080] Comparative Example 2

[0081] A vitamin E-loaded lyocell fiber is prepared in a manner that differs from that of Example 1 in that the proportion of vitamin E-loaded nanocrystalline cellulose added to the lyocell spinning solution in step S3 is 12 wt%, while the steps are the same as those in Example 1.

[0082] Comparative Example 3

[0083] A method for preparing vitamin E-loaded lyocell fiber includes the following steps:

[0084] S1: Add wood pulp with a degree of polymerization of 800 to water, adjust the pH to 6, add cellulase to activate for 1 hour, and then add sodium hydroxide to adjust the pH to 9 to terminate the activation and obtain pulp porridge.

[0085] The porridge was vacuum pressed and dehydrated to obtain hydrated cellulose with a water content of 48wt%, which was then crushed into 3cm×3cm particles.

[0086] The pulverized hydrated cellulose was added to a 62wt% N-methylmorpholine-N-oxide aqueous solution at a material-to-liquid ratio of 1:4. After pre-dissolving at 70℃, the solution was dissolved in a dissolving machine under a vacuum of 4 kPa to obtain a lyocell spinning solution containing 10.6wt% lyocell fiber.

[0087] S2: Preparation of Vitamin E Microcapsules

[0088] Vitamin E succinate, carbon nanotubes, Tween 80 and sodium dodecyl sulfate in a mass ratio of 30:5:1.5:1 were mixed at 70°C and 15000 rpm for 10 min to form a homogeneous oil phase.

[0089] The oil phase was added to deionized water at an oil-water ratio of 3:1, and emulsified at 10,000 rpm for 20 min to obtain an O / W emulsion.

[0090] Add 10 wt% of silicone-modified polyurethane water-dispersible resin to the O / W emulsion, dry at 800 mPa·s and 25°C to cure the material and obtain vitamin E microcapsules.

[0091] S3: Vitamin E microcapsules were added to the lyocell spinning solution at a ratio of 5 wt%, and ultrasonically dispersed at 40 kHz for 30 min to obtain a mixed spinning solution. The mixed spinning solution was then spun by dry-jet wet spinning at a spinning speed of 50 m / min. The spinneret orifice of the mixed spinning solution was 0.06 mm, the spinning air gap was 25 mm, the spinning air humidity was 70%, the coagulation bath concentration was 18% NMMO aqueous solution, and the coagulation bath temperature was 25 ℃. After three-stage countercurrent washing, bleaching, and oiling, the solution was relaxed and dried at 80 ℃, and then sheared to form short fibers to obtain vitamin E-loaded lyocell fibers.

[0092] Comparative Example 4

[0093] A method for preparing lyocell fiber includes the following steps:

[0094] S1: Add wood pulp with a degree of polymerization of 800 to water, adjust the pH to 6, add cellulase to activate for 1 hour, and then add sodium hydroxide to adjust the pH to 9 to terminate the activation and obtain pulp porridge.

[0095] The porridge was vacuum pressed and dehydrated to obtain hydrated cellulose with a water content of 48wt%, which was then crushed into 3cm×3cm particles.

[0096] The pulverized hydrated cellulose was added to a 62wt% N-methylmorpholine-N-oxide aqueous solution at a material-to-liquid ratio of 1:4. After pre-dissolving at 70℃, the solution was dissolved in a dissolving machine under a vacuum of 4 kPa to obtain a lyocell spinning solution containing 10.6wt% lyocell fiber.

[0097] S2: The spinning solution is formed by dry-jet wet spinning at a spinning speed of 100m / min. The spinneret orifice diameter is 0.04mm, the spinning air gap is 20mm, the spinning air humidity is 60%, the coagulation bath concentration is 10% NMMO aqueous solution, and the coagulation bath temperature is 25℃. After three-stage countercurrent water washing, bleaching, and oiling, it is relaxed and dried at 80℃, and then sheared to form short fibers to obtain Lyocell fibers.

[0098] Performance testing

[0099] The following performance tests were conducted on the vitamin E-loaded lyocell fibers obtained in the examples and comparative examples. Each test was performed three times, and the average of the three test results was taken as the final result and recorded in Tables 1-2.

[0100] 1. The initial vitamin E loading, the loading after 50 washes, and the loading after 24 hours of in vitro sustained release in the vitamin E-loaded lyocell fibers obtained in Examples 1-6 and Comparative Examples 1-3 were determined by HPLC. The retention rate after 50 washes and the release rate after 24 hours of in vitro sustained release were calculated. The in vitro release was conducted under simulated sweat conditions at pH 5.5. The specific detection parameters are as follows:

[0101] The standard was tocopherol; the chromatograph model was Waters E2695.

[0102] Chromatographic column: Waters Symmetry C18 (5μm, 250×4.6mm);

[0103] Detection wavelength: 292 nm; Mobile phase: acetonitrile-water (90:10, v / v), with 0.1% formic acid added;

[0104] Flow rate: 0.8-1.0 mL / min; injection volume: 20 μL; run time: 18 min;

[0105] 2. Mechanical properties: In accordance with the relevant provisions of GB / T14337-2022, the breaking strength and elastic modulus of the vitamin E-loaded lyocell fibers obtained in Examples 1-6, Comparative Examples 1-2 and 4 were tested.

[0106] 3. Antibacterial properties: In accordance with the relevant provisions of GB / T20944.3-2008, the antibacterial effect of vitamin E-loaded lyocell fiber obtained in Examples 1-6, Comparative Examples 1-2 and 4 on Staphylococcus aureus was tested.

[0107] 4. UV protection factor: In accordance with the relevant provisions of GB / T18830-2009, the UV protection factor of the vitamin E-loaded lyocell fibers obtained in Examples 1-6, Comparative Examples 1-2 and 4 was tested.

[0108] Table 1

[0109]

[0110] Table 2

[0111]

[0112] As can be seen from the performance test results of Examples 1-6 in Table 1, this application effectively loads vitamin E by covalently binding it with vitamin E succinate after aminolation treatment of nanocrystalline cellulose. Then, by utilizing the homology between nanocrystalline cellulose and lyocell fiber, the compatibility bottleneck of physical mixing in traditional processes is overcome, which significantly improves the vitamin E loading capacity and loading stability of lyocell fiber. Combined with the barrier effect of nanocrystalline cellulose, the slow release of vitamin E is achieved, which prolongs the durability of the skin care and health benefits of the fiber.

[0113] Based on the process of loading vitamin E onto lyocell fibers using microcapsules as the core material in Example 1 and Comparative Example 3, the initial drug loading of this application is increased by 34.6%, and the retention rate of vitamin E after 50 washes is ≥85%, an increase of 80.9%. The in vitro release is also more stable over 24 hours. This is because the hydrolysis time of the amide bond in the environment simulating human sweat pH=5.5 is more than 72 hours. Combined with the barrier effect of nanocrystalline cellulose, diffusion can be further delayed, and the release of vitamin E active ingredients is more controllable. This effectively reduces the problem of excessive release or insufficient release, resulting in more lasting efficacy.

[0114] As can be seen from the test results of Examples 1-6 in Table 2, the nanocrystalline cellulose used in this application as a carrier of vitamin E can be uniformly dispersed in the lyocell spinning solution. This not only significantly improves the effective loading capacity and loading stability of vitamin E in lyocell fibers, giving lyocell fibers excellent antibacterial properties and ultraviolet absorption characteristics, but also enhances the density of lyocell fibers, effectively inhibits the formation and expansion of micropores inside the fibers, and significantly improves the mechanical properties of lyocell fibers such as breaking strength and elastic modulus.

[0115] According to the performance test results of Example 1 and Comparative Example 4, compared with pure lyocell fiber, the lyocell fiber obtained by adding 5-10 wt% of vitamin E-loaded nanocrystalline cellulose to the blend spinning solution of this application showed an increase in breaking strength of 15.8%, elastic modulus of 17.6%, antibacterial rate of 92.3%, and UV protection factor of 642%. This indicates that the use of nanocrystalline cellulose as a carrier for vitamin E to load vitamin E onto lyocell fiber in this application not only improves the compatibility between vitamin E and lyocell fiber, significantly improving the loading capacity, loading stability, and efficacy durability of lyocell fiber for vitamin E, but also improves the mechanical, antibacterial, and UV absorption properties of lyocell fiber while retaining its own excellent properties.

[0116] According to the performance test results of Examples 1-6 and Comparative Examples 1-2 in Table 1-2, it can be seen that when the blended lyocell fiber and nanocrystalline cellulose loaded with vitamin E is spun into dry-jet wet-spinning solution, the proportion of nanocrystalline cellulose loaded with vitamin E added to the lyocell spinning solution is 5-10 wt%. This ensures that the vitamin E-loaded lyocell fiber has a high drug loading capacity and sustained-release performance, as well as excellent mechanical, antibacterial and ultraviolet absorption properties. At the same time, it can save raw materials, prevent waste and reduce costs.

[0117] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A process for the preparation of a vitamin E loaded lyocell fibre, characterized in that, The method comprises the following steps: S1: adding nanocrystalline cellulose into an amino silane coupling agent solution for amine modification to obtain amine-modified nanocrystalline cellulose; S2: dissolving vitamin E succinate in a PBS buffer to prepare a vitamin E succinate solution, adding EDC and NHS in a molar ratio of (3.5-4.5):1, stirring and activating for 20-30 min to obtain an activated ester solution, and then adding the amine-modified nanocrystalline cellulose to mix and perform amide reaction, and freeze-drying to obtain vitamin E-loaded nanocrystalline cellulose; S3: adding the vitamin E-loaded nanocrystalline cellulose into a lyocell spinning solution in a proportion of 5-10 wt% to obtain a mixed spinning solution, and spinning and forming to obtain vitamin E-loaded lyocell fibers.

2. The process for the preparation of vitamin E-loaded lyocell fibers according to claim 1, characterized in that, The amine group density of the amine-modified nanocrystalline cellulose is ≥1.2 mmol / g.

3. The process for the preparation of vitamin E-loaded lyocell fibers according to claim 1, characterized in that, The mass ratio of the amine-modified nanocrystalline cellulose to the vitamin E succinate in step S2 is 1:(0.5-1.5).

4. The process for the preparation of vitamin E-loaded lyocell fibers according to claim 1, characterized in that, The method for preparing the lyocell spinning solution comprises the following steps: adding pulp into water, adjusting the pH to 4-6, adding cellulase for activation, then adjusting the pH to 9-13 to terminate the activation to obtain pulp; squeezing and dewatering the pulp to obtain water-containing cellulose with a water content of 40-60 wt%; adding the water-containing cellulose into a 50-88 wt% N-methylmorpholine-N-oxide aqueous solution for dissolution to obtain a lyocell spinning solution, wherein the content of lyocell fibers is 8-12 wt%.

5. The process for the preparation of vitamin E-loaded lyocell fibers according to claim 1, characterized in that, The dry-jet wet spinning process is used for spinning and forming in step S3.

6. The process for the preparation of vitamin E-loaded lyocell fibers according to claim 5, characterized in that, The spinning parameters of the dry-jet wet spinning process are as follows: the spinning speed is 50-100 m / min, the mixed spinning solution passes through a spinneret aperture of 0.04-0.08 mm, the spinning air gap is 20-40 mm, the spinning air humidity is 60-80%, and the coagulation bath concentration is 10-20%.

7. A vitamin E-loaded lyocell fiber prepared by the method for preparing a vitamin E-loaded lyocell fiber according to any one of claims 1-6.

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