Skin-moistening anti-oxidation lyocell fiber and preparation method thereof

Abstract

The invention relates to a skin-moistening antioxidant which is prepared by sequentially carrying out vegetable oil modification and polysaccharide modification on an antioxidant, in the process of preparing lyocell fibers by taking the skin-moistening antioxidant as an additive, the skin-moistening antioxidant is mixed with cellulose in a swelling stage, the dispersion uniformity of active matters in spinning slurry is improved, and the dispersion uniformity of the active matters in the spinning slurry is improved. The spinnability and the breaking strength of the fiber are improved. Meanwhile, the skin moistening antioxidant has good transdermal absorption performance, good solubility in spinning slurry and good compatibility with cellulose, the skin moistening antioxidant can be more uniformly and firmly attached to fibers in the fiber forming process, and the skin moistening performance, the oxidation resistance and the washing fastness of the fibers are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of regenerated cellulose fibers, and in particular relates to a skin-moistening and anti-oxidative lyocell fiber and a preparation method thereof. Background Art

[0002] With the improvement of living standards, consumers have put forward higher requirements for the quality, functionality and environmental protection of textiles. As a new type of green regenerated cellulose fiber, Lyocell fiber has shown great development potential in the textile industry with its high strength, excellent moisture absorption performance and environmentally friendly production process. Compared with traditional viscose fiber, Lyocell fiber has excellent performance in dyeing performance, shrinkage control, hand feel and skin-friendliness, becoming a new favorite in the market.

[0003] At present, functional fibers such as modified viscose fibers with antibacterial, anti-mite, flame retardant, deodorizing and skin care properties have been used for many years and are very popular among consumers. However, although Lyocell fibers are in a stage of rapid capacity expansion and quality improvement, they are still in the initial stage of functional modification, especially the development of high-end functional Lyocell fibers such as skin moisturizing and anti-oxidation properties still has a large gap.

[0004] For modern consumers, moisturizing and antioxidant functions are not only the pursuit of healthy life, but also an important manifestation of high added value of textiles. Currently, there is a lack of moisturizing antioxidants with good compatibility with cellulose in the market, which limits the application of lyocell fiber in the field of high-end functional textiles. Summary of the invention

[0005] The present invention aims to develop a skin-emollient antioxidant with good compatibility with cellulose, and to prepare lyocell fibers with excellent spinnability, high strength and significant skin-emollient antioxidant effects through scientific formula design and advanced spinning technology.

[0006] To achieve the above objectives, this application is implemented through the following technical solutions: The present application provides a method for preparing skin-emollient and antioxidant lyocell fiber, comprising the following steps: S1. Swelling: adding 1 to 5 parts of a skin-emollient antioxidant and 8 to 12 parts of cellulose pulp to 80 to 90 parts of an aqueous solution of N-methylmorpholine oxide by weight, and mixing and swelling the mixture to obtain a swelling slurry, wherein the skin-emollient antioxidant is prepared by sequentially modifying the antioxidant with vegetable oil and polysaccharide; S2, dissolving: the obtained swollen slurry is sent to a dissolving kettle, then heated and vacuumed, and the spinning slurry is obtained after dehydration, dissolution, degassing and filtration; S3, spinning: the obtained spinning slurry is filtered, conveyed to the metering pump by a booster pump, and ejected through a spinneret, and a dry-jet wet spinning process is adopted. After coagulation and regeneration in a coagulation bath and drawing, a moisturizing and antioxidant Lyocell fiber is obtained.

[0007] As a further improvement of the present application, in step S1, the degree of polymerization of cellulose in the cellulose pulp is 600-800, the concentration of the N-methylmorpholine oxide aqueous solution is 75%-83%, and the swelling temperature is 80°C-90°C.

[0008] As a further improvement of the present application, in step S2, the vacuum degree after vacuuming is 0.05MPa~0.1MPa, and after dehydration, the concentration of N-methylmorpholine oxide in the swelling slurry is 87%~90%, and the dissolution temperature is 100℃~130℃.

[0009] As a further improvement of the present application, in step S3, the coagulation bath is an aqueous solution of N-methylmorpholine oxide, the temperature of the coagulation bath is 20°C to 30°C, the concentration of N-methylmorpholine oxide in the coagulation bath is 15% to 25%, and the stretching multiple is 1.1 to 1.3.

[0010] As a further improvement of the present application, in step S1, the antioxidant is selected from any one of epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, quercetin, naringenin, apigenin, and anthocyanin; the vegetable oil is selected from any one of camellia oil, olive oil, argan oil, jojoba oil, shea butter, and avocado oil; the polysaccharide is polymerized by β-1,4 glycosidic bonds, and the number average molecular weight of the polysaccharide is 120KD to 150KD.

[0011] As a further improvement of the present application, in step S1, the polysaccharide is selected from any one of sodium hyaluronate, alginate, konjac gum, xanthan gum, and guar gum.

[0012] As a further improvement of the present application, the emollient antioxidant is prepared by the following steps: A1. Dissolve 1 to 5 parts of antioxidant, 5 to 20 parts of vegetable oil, 1 to 5 parts of cholesterol, and 20 to 30 parts of Tween 20 in 80 to 100 parts of ethanol by weight, and mix thoroughly to obtain a first mixed solution; A2, slowly dripping 1 part of the first mixed solution into 1 part to 5 parts of deionized water, stirring at high speed for 1 hour to 2 hours, and then removing ethanol by rotary evaporation to obtain a vegetable oil modified antioxidant suspension; A3, dissolving 1 to 5 parts of the above vegetable oil modified antioxidant suspension and 5 to 10 parts of polysaccharide in 80 to 100 parts of deionized water, and stirring thoroughly for 2 to 4 hours to obtain a second mixed solution; A4. Freeze the second mixed solution at -10°C to -20°C for 18 to 24 hours, and thaw at 15 to 25°C for 2 to 6 hours. Repeat the freezing and thawing steps for several times, and then vacuum dry the mixture at a vacuum degree of 0.1 to 1 Pa to obtain a skin moisturizing antioxidant.

[0013] As a further improvement of the present application, in step A4, the number of cycles is 5 to 10 times.

[0014] To achieve the above objectives, the present application also provides a skin-moisturizing and antioxidant lyocell fiber prepared by the above-mentioned preparation method.

[0015] As a further improvement of the present application, the fiber has a fineness of 0.9 to 2.22 dtex, a dry breaking strength of 3.8 to 4.5 cN / dtex, and a wet breaking strength of 3.5 to 4.0 cN / dtex.

[0016] The beneficial effect of the present application is that the present application provides a skin-emollient antioxidant prepared by sequentially modifying an antioxidant with vegetable oil and polysaccharide, and in the process of preparing fibers using the skin-emollient antioxidant as an additive, the skin-emollient antioxidant is mixed with cellulose in the swelling stage, thereby improving the uniformity of dispersion of active substances in the spinning slurry, and improving the spinnability and breaking strength of the fibers. At the same time, the skin-emollient antioxidant has good transdermal absorption performance, good solubility in the spinning slurry, and good compatibility with cellulose, and the skin-emollient antioxidant can be more evenly and firmly attached to the fibers during the fiber forming process, thereby improving the emollient, antioxidant and wash resistance of the fibers. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solution of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with specific implementation methods.

[0019] Example 1 Preparation of Emollient Antioxidant: A1. Dissolve 1 part of epicatechin, 5 parts of camellia oil, 1 part of cholesterol and 20 parts of Tween 20 in 80 parts of ethanol by weight, and mix thoroughly to obtain a first mixed solution; A2, slowly dripping 1 part of the first mixed solution into 1 part of deionized water, stirring at high speed for 2 hours, and then removing ethanol by rotary evaporation to obtain a vegetable oil modified antioxidant suspension; A3, dissolving 1 part of the above vegetable oil modified antioxidant suspension and 5 parts of sodium hyaluronate with a number average molecular weight of 120KD in 80 parts of deionized water, and stirring for 4 hours to obtain a second mixed solution; A4. Freeze the second mixed solution at -10°C for 24 hours, thaw at 15°C for 6 hours, cycle freezing and thawing for 5 times, and then vacuum dry at a vacuum degree of 0.1 Pa to obtain a skin moisturizing antioxidant.

[0020] Preparation of skin-moisturizing and antioxidant lyocell fiber: S1, swelling: by weight, 1 part of the above-prepared emollient antioxidant and 8 parts of cellulose pulp with a degree of polymerization of 800 are pumped into a pre-dissolving kettle containing 80 parts of a 75% aqueous solution of N-methylmorpholine oxide through a first screw pump, and the three are fully mixed and swollen by tumbling and extruding at 80° C. to obtain a swelling slurry; S2, dissolving: the swelling slurry obtained in step S1 is fed into a dissolving kettle through a second screw pump, and then heated and vacuumed to 0.05 MPa by a thin film evaporator, and a spinning slurry is obtained after dehydration, dissolution, degassing and filtration. After dehydration, the concentration of N-methylmorpholine oxide in the swelling slurry is 87%, and the dissolution temperature is 130°C; S3. Spinning: The obtained spinning slurry is filtered, conveyed to the metering pump by a booster pump, sprayed out through a spinneret, and a dry-jet wet spinning process is adopted. It is coagulated and regenerated in a 15% N-methylmorpholine oxide aqueous solution at a temperature of 20°C. After being stretched by 1.1 times, a moisturizing and antioxidant Lyocell fiber is obtained.

[0021] Example 2 Preparation of Emollient Antioxidant: A1. Dissolve 5 parts of quercetin, 20 parts of olive oil, 5 parts of cholesterol and 30 parts of Tween 20 in 100 parts of ethanol by weight, and mix thoroughly to obtain a first mixed solution; A2, slowly dripping 1 part of the first mixed solution into 5 parts of deionized water, stirring at high speed for 1 hour, and then removing ethanol by rotary evaporation to obtain a vegetable oil modified antioxidant suspension; A3, above-mentioned 5 parts of vegetable oil modified antioxidant suspensions and 10 parts of number average molecular weight are dissolved in 100 parts of deionized water of the konjac glucomannan of 150KD, after fully stirring for 2h, obtain the second mixed solution; A4. Freeze the second mixed solution at -20°C for 18 hours, thaw at 25°C for 2 hours, cycle freezing and thawing for 10 times, and then vacuum dry at a vacuum degree of 1 Pa to obtain a skin moisturizing antioxidant.

[0022] Preparation of skin-moisturizing and antioxidant lyocell fiber: S1, swelling: by weight, 5 parts of the above-prepared emollient antioxidant and 12 parts of cellulose pulp with a degree of polymerization of 600 are fed into a pre-dissolving kettle containing 90 parts of an 83% aqueous solution of N-methylmorpholine oxide through a first screw pump, and the three are fully mixed and swollen by tumbling and extruding at 90° C. to obtain a swelling slurry; S2, dissolving: the swelling slurry obtained in step S1 is fed into a dissolving kettle through a second screw pump, and then heated and evacuated to 0.1 MPa by a thin film evaporator, and a spinning slurry is obtained after dehydration, dissolution, degassing and filtration. After dehydration, the concentration of N-methylmorpholine oxide in the swelling slurry is 90%, and the dissolution temperature is 100°C; S3. Spinning: The obtained spinning slurry is filtered, conveyed to the metering pump by a booster pump, sprayed out through a spinneret, and a dry-jet wet spinning process is adopted. It is coagulated and regenerated in a 25% N-methylmorpholine oxide aqueous solution at a temperature of 30°C. After being stretched 1.3 times, a moisturizing and antioxidant Lyocell fiber is obtained.

[0023] Example 3 Preparation of Emollient Antioxidant: A1. Dissolve 3 parts of naringenin, 10 parts of argan oil, 3 parts of cholesterol, and 25 parts of Tween 20 in 90 parts of ethanol by weight, and mix thoroughly to obtain a first mixed solution; A2, slowly dripping 1 part of the first mixed solution into 3 parts of deionized water, stirring at high speed for 1.5 hours, and then removing ethanol by rotary evaporation to obtain a vegetable oil modified antioxidant suspension; A3, dissolving the above 3 parts of vegetable oil modified antioxidant suspension and 8 parts of alginate with a number average molecular weight of 135KD in 90 parts of deionized water, and stirring for 3 hours to obtain a second mixed solution; A4. Freeze the second mixed solution at -15°C for 20 hours, thaw at 20°C for 4 hours, cycle freezing and thawing for 7 times, and then vacuum dry at a vacuum degree of 0.5 Pa to obtain a skin moisturizing antioxidant.

[0024] Preparation of skin-moisturizing and antioxidant lyocell fiber: S1, swelling: by weight, 3 parts of the above-prepared emollient antioxidant and 10 parts of cellulose pulp with a degree of polymerization of 700 are fed into a pre-dissolving kettle containing 85 parts of an 80% aqueous solution of N-methylmorpholine oxide through a first screw pump, and the three are fully mixed and swollen by tumbling and extruding at 85° C. to obtain a swelling slurry; S2, dissolving: the swelling slurry obtained in step S1 is fed into a dissolving kettle through a second screw pump, and then heated and vacuumed to 0.08 MPa by a thin film evaporator, and a spinning slurry is obtained after dehydration, dissolution, degassing and filtration. After dehydration, the concentration of N-methylmorpholine oxide in the swelling slurry is 89%, and the dissolution temperature is 110°C; S3. Spinning: The obtained spinning slurry is filtered, conveyed to the metering pump by a booster pump, sprayed out through a spinneret, and subjected to dry-jet wet spinning process. It is coagulated and regenerated in a 20% N-methylmorpholine oxide aqueous solution at a temperature of 25°C. After being stretched 1.2 times, a moisturizing and antioxidant Lyocell fiber is obtained.

[0025] Example 4 Preparation of Emollient Antioxidant: A1, by weight, 1 part of apigenin, 5 parts of shea butter, 1 part of cholesterol, 20 parts of Tween 20 were dissolved in 80 parts of ethanol, and fully mixed to obtain the first mixed solution; A2, slowly dripping 1 part of the first mixed solution into 1 part of deionized water, stirring at high speed for 2 hours, and then removing ethanol by rotary evaporation to obtain a vegetable oil modified antioxidant suspension; A3, dissolving 1 part of the above vegetable oil modified antioxidant suspension and 5 parts of xanthan gum with a number average molecular weight of 125KD in 80 parts of deionized water, and stirring for 4 hours to obtain a second mixed solution; A4. Freeze the second mixed solution at -10°C for 24 hours, thaw at 15°C for 6 hours, cycle freezing and thawing for 5 times, and then vacuum dry at a vacuum degree of 0.1 Pa to obtain a skin moisturizing antioxidant.

[0026] Preparation of skin-moisturizing and antioxidant lyocell fiber: S1, swelling: by weight, 1 part of the above-prepared emollient antioxidant and 8 parts of cellulose pulp with a degree of polymerization of 750 are pumped into a pre-dissolving kettle containing 80 parts of a 75% aqueous solution of N-methylmorpholine oxide through a first screw pump, and the three are fully mixed and swollen by tumbling and extruding at 80° C. to obtain a swelling slurry; S2, dissolving: the swelling slurry obtained in step S1 is fed into a dissolving kettle through a second screw pump, and then heated and vacuumed to 0.05 MPa by a thin film evaporator, and a spinning slurry is obtained after dehydration, dissolution, degassing and filtration. After dehydration, the concentration of N-methylmorpholine oxide in the swelling slurry is 87%, and the dissolution temperature is 130°C; S3. Spinning: The obtained spinning slurry is filtered, conveyed to the metering pump by a booster pump, sprayed out through a spinneret, and a dry-jet wet spinning process is adopted. It is coagulated and regenerated in a 15% N-methylmorpholine oxide aqueous solution at a temperature of 20°C. After being stretched by 1.1 times, a moisturizing and antioxidant Lyocell fiber is obtained.

[0027] Example 5 Preparation of Emollient Antioxidant: A1. Dissolve 1 part of epicatechin gallate, 5 parts of avocado oil, 1 part of cholesterol, and 20 parts of Tween 20 in 80 parts of ethanol by weight, and mix thoroughly to obtain a first mixed solution; A2, slowly dripping 1 part of the first mixed solution into 1 part of deionized water, stirring at high speed for 2 hours, and then removing ethanol by rotary evaporation to obtain a vegetable oil modified antioxidant suspension; A3, dissolving 1 part of the above vegetable oil modified antioxidant suspension and 5 parts of guar gum with a number average molecular weight of 125KD in 80 parts of deionized water, stirring for 4 hours, to obtain a second mixed solution; A4. Freeze the second mixed solution at -10°C for 24 hours, thaw at 15°C for 2 hours, cycle freezing and thawing for 5 times, and then vacuum dry at a vacuum degree of 0.1 Pa to obtain a skin moisturizing antioxidant.

[0028] Preparation of skin-moisturizing and antioxidant lyocell fiber: S1, swelling: by weight, 1 part of the above-prepared emollient antioxidant and 8 parts of cellulose pulp with a degree of polymerization of 750 are pumped into a pre-dissolving kettle containing 80 parts of a 75% aqueous solution of N-methylmorpholine oxide through a first screw pump, and the three are fully mixed and swollen by tumbling and extruding at 80° C. to obtain a swelling slurry; S2, dissolving: the swelling slurry obtained in step S1 is fed into a dissolving kettle through a second screw pump, and then heated and vacuumed to 0.05 MPa by a thin film evaporator, and a spinning slurry is obtained after dehydration, dissolution, degassing and filtration. After dehydration, the concentration of N-methylmorpholine oxide in the swelling slurry is 87%, and the dissolution temperature is 130°C; S3. Spinning: The obtained spinning slurry is filtered, conveyed to the metering pump by a booster pump, sprayed out through a spinneret, and a dry-jet wet spinning process is adopted. It is coagulated and regenerated in a 15% N-methylmorpholine oxide aqueous solution at a temperature of 20°C. After being stretched by 1.1 times, a moisturizing and antioxidant Lyocell fiber is obtained.

[0029] Comparative Example 1 Different from Example 1, the number average molecular weight of sodium hyaluronate is 100 KD.

[0030] Comparative Example 2 Different from Example 1, the number average molecular weight of sodium hyaluronate is 185KD.

[0031] Comparative Example 3 Different from Example 1, the number of cycles of the freezing and thawing steps is 3 times.

[0032] Comparative Example 4 Different from Example 1, the number of cycles of the freezing and thawing steps is 12 times.

[0033] Comparative Example 5 The difference from Example 1 is that in step S1, the concentration of N-methylmorpholine oxide in the aqueous solution of N-methylmorpholine oxide is 72%.

[0034] Comparative Example 6 The difference from Example 1 is that in step S1, the concentration of N-methylmorpholine oxide in the aqueous solution of N-methylmorpholine oxide is 85%.

[0035] Comparative Example 7 Different from Example 1, epicatechin is not added in step A1, that is, no antioxidant is included.

[0036] Comparative Example 8 The difference from Example 1 is that no camellia oil is added in step A1, that is, the vegetable oil is not modified.

[0037] Comparative Example 9 Different from Example 1, in step A3, water-soluble starch is used to replace sodium hyaluronate.

[0038] Comparative Example 10 Different from Example 1, in step A3, sodium hyaluronate was not added, that is, polysaccharide modification was not performed, and vacuum drying was directly performed.

[0039] Comparative Example 11 Different from Example 1, the antioxidant was not modified with vegetable oil or polysaccharide, and epicatechin, camellia oil and sodium hyaluronate were directly added into the pre-dissolving kettle containing N-methylmorpholine oxide aqueous solution, fully mixed with cellulose pulp, and directly swelled.

[0040] Comparative Example 12 Different from Example 1, no moisturizing antioxidant is added in the swelling step, but the moisturizing antioxidant is directly added in the dissolving step, so that the moisturizing antioxidant is directly mixed and dissolved with the cellulose swelling slurry to obtain the spinning slurry.

[0041] The dry breaking strength and wet breaking strength of the fiber were tested with reference to GB / T 14337-2022. The fiber of the present invention was spun, weaved, printed and dyed to obtain a pure lyocell fiber fabric with a specification of 60S*60S / 182*105. The change rate of human skin moisture before and after use of the fabric was tested with reference to Appendix A of T / CTES 1035-2021. The antioxidant capacity of the fabric was tested with reference to T / CCTA 20102-2023. Washing was performed 20 times in accordance with the 4N procedure specified in GB / T 8629-2017. The dry breaking strength and wet breaking strength of the fiber, and the moisturizing and antioxidant performance data of the fabric before and after washing are shown in Table 1.

[0042] Table 1: Fabric performance data before and after washing

[0043] The fibers prepared in Examples 1-5 have good dry breaking strength (dry strength) and wet breaking strength (wet strength), and the corresponding pure lyocell fiber fabrics have good moisture retention and free radical removal functions, and the efficacy does not decay significantly after washing. This shows that the skin-moisturizing and antioxidant lyocell fibers in the examples have good spinnability, good strength, and significant efficacy.

[0044] Compared with Example 1, the molecular weight of sodium hyaluronate in Comparative Example 1 is lower, that is, when the molecular weight of the polysaccharide is lower, the obtained emollient antioxidant is directly dissolved in a 75% concentration of N-methylmorpholine oxide aqueous solution, and the viscosity of the swelling slurry is greatly increased, which affects the uniformity of dispersion of the active substance in the spinning slurry, resulting in a decrease in the breaking strength, emollient properties and antioxidant properties of the fiber.

[0045] Compared with Example 1, in Comparative Example 2, the molecular weight of sodium hyaluronate is too large, that is, when the molecular weight of the polysaccharide is too large, the obtained emollient antioxidant has poor compatibility with cellulose in the spinning slurry, resulting in a decrease in the breaking strength, emollient properties and antioxidant properties of the fiber.

[0046] Compared with Example 1, the number of freeze-thaw cycles in Comparative Example 3 is less, and the obtained emollient antioxidant is directly dissolved in a 75% concentration of N-methylmorpholine oxide aqueous solution, and the viscosity of the swelling slurry is greatly increased, which affects the uniformity of dispersion of the active substance in the spinning slurry, resulting in a decrease in the breaking strength, emollient properties and antioxidant properties of the fiber.

[0047] Compared with Example 1, the number of freeze-thaw cycles in Comparative Example 4 is greater, and the production cost and energy consumption are increased, but the fiber breaking strength, emollient properties and antioxidant properties are not significantly improved.

[0048] Compared with Example 1, the concentration of the N-methylmorpholine oxide aqueous solution in the swelling stage in Comparative Example 5 is lower, the swelling of the emollient antioxidant is insufficient, and some of the incompletely swollen emollient antioxidants are directly dissolved in the 87% concentration of the N-methylmorpholine oxide aqueous solution, the viscosity of the spinning slurry increases, and the uniformity of the active substance dispersion decreases, resulting in a decrease in the breaking strength, emollient properties and antioxidant properties of the fiber.

[0049] Compared with Example 1, the concentration of the N-methylmorpholine oxide aqueous solution in the swelling stage in Comparative Example 6 is higher, and the obtained emollient antioxidant is directly dissolved in the 85% concentration N-methylmorpholine oxide aqueous solution, and the viscosity of the swelling slurry is greatly increased, which affects the uniformity of the dispersion of the active substance in the spinning slurry, resulting in a decrease in the breaking strength, emollient properties and antioxidant properties of the fiber.

[0050] Compared with Example 1, the first mixed solution of Comparative Example 7 does not contain epicatechin, that is, does not contain antioxidants, and the antioxidant function of the Lyocell fiber fabric is significantly reduced.

[0051] Compared with Example 1, the first mixed liquid of Comparative Example 8 does not contain camellia oil, that is, the vegetable oil is not modified, the antioxidant (such as epicatechin, etc.) is easily oxidized during the production process, and the permeability of the moisturizing antioxidant is general, and the moisturizing and antioxidant properties of the lyocell fiber fabric are not ideal.

[0052] Compared with Example 1, Comparative Example 9 uses water-soluble starch without β-1,4 glycosidic bonds as the polysaccharide, and the resulting emollient antioxidant has poor compatibility with cellulose in the spinning slurry, resulting in a decrease in the breaking strength, emollient properties and antioxidant properties of the fiber.

[0053] Compared with Example 1, Comparative Example 10 did not undergo polysaccharide modification, and had poor compatibility with cellulose in the spinning slurry. In addition, the active substance had poor adhesion in the fiber and was easily lost, resulting in a decrease in the fiber's breaking strength and antioxidant properties. At the same time, the wash resistance of the Lyocell fiber fabric's moisturizing and antioxidant functions also decreased significantly.

[0054] Compared with Example 1, in Comparative Example 11, epicatechin, camellia oil and sodium hyaluronate were directly added to the aqueous solution of N-methylmorpholine oxide and swelled with cellulose to prepare a swelling slurry. Epicatechin and camellia oil were unevenly distributed in the spinning slurry and lost more in the coagulation bath, resulting in a decrease in the breaking strength, emollient properties and antioxidant properties of the fiber.

[0055] In Comparative Example 12, the emollient antioxidant was not swollen, but was directly mixed and dissolved with the cellulose swollen slurry in a dissolving kettle to obtain a spinning slurry. The unswollen emollient antioxidant was directly dissolved in an 87% concentration of N-methylmorpholine oxide aqueous solution, and the viscosity of the spinning slurry increased, the uniformity of the active substance dispersion decreased, and the fiber breaking strength, emollient performance and antioxidant performance all decreased.

[0056] In addition, the comparison between Comparative Examples 1-12 and Example 1 also shows that the decrease in compatibility or uniformity of the active substance in the lyocell spinning solution not only leads to a decrease in the fiber breaking strength, but also affects the moisturizing and antioxidant effects of the lyocell fiber fabric to a certain extent.

[0057] In summary, antioxidants are extremely unstable in N-methylmorpholine oxide aqueous solution and are easily oxidized and discolored during the spinning process, thus becoming ineffective. Vegetable oil-modified antioxidants ensure that the antioxidants are not destroyed by N-methylmorpholine oxide, and at the same time have good fat solubility and moisturizing properties, which improves the transdermal absorption of the modified antioxidants and ensures the functionality of the active substances in lyocell fibers and their products.

[0058] In order to further improve the solubility and compatibility of vegetable oil modified antioxidants in lyocell spinning solution, the present invention also uses polysaccharides with specific structures and molecular weights to modify vegetable oil modified antioxidants to obtain emollient antioxidants. The polysaccharide selected in the technical solution of the present application is a polysaccharide containing β-1,4 glycosidic bonds, which has good emollient and moisturizing properties, and has similar glycosidic bonds and molecular weights to cellulose, which greatly improves the addition amount and compatibility of the emollient antioxidant in the spinning slurry, and improves the spinnability and functionality of the fiber. In addition, the polysaccharide weakens the crystallinity of the fiber at the supramolecular scale, produces more adsorption sites during the spinning process, promotes more emollient antioxidants to be more evenly and firmly attached to the fiber, reduces the loss of active substances, and improves the fiber's washability.

[0059] In the present application, the emollient antioxidant and cellulose are swollen in an aqueous solution of N-methylmorpholine oxide and mixed in the swelling stage, which has a significant advantage over mixing in the dissolution stage. The emollient antioxidant and cellulose are mixed before the swelling stage, and N-methylmorpholine oxide acts on the microcrystalline region of cellulose and the emollient antioxidant, and both slowly and fully swell, which is conducive to the uniform dispersion of the active substance in the spinning solution in the later dissolution stage, improving the spinnability of the fiber and increasing the breaking strength of the fiber.

[0060] Only within the preset concentration range of the N-methylmorpholine oxide aqueous solution can the emollient antioxidant swell fully without directly dissolving, ensuring that the active ingredient is evenly dispersed in the spinning slurry, thereby ensuring that the fiber has excellent breaking strength, emollient properties and antioxidant properties.

[0061] Although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0062] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present application. They are not intended to limit the scope of protection of the present application. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preparing a skin-emollient and antioxidant lyocell fiber, characterized in that: The steps include: S1. Swelling: adding 1 to 5 parts of a skin-emollient antioxidant and 8 to 12 parts of cellulose pulp to 80 to 90 parts of an aqueous solution of N-methylmorpholine oxide by weight, and mixing and swelling the mixture to obtain a swelling slurry, wherein the skin-emollient antioxidant is prepared by sequentially modifying the antioxidant with vegetable oil and polysaccharide; S2, dissolving: the obtained swollen slurry is sent to a dissolving kettle, then heated and vacuumed, and the spinning slurry is obtained after dehydration, dissolution, degassing and filtration; S3, spinning: the obtained spinning slurry is filtered, conveyed to the metering pump by a booster pump, and ejected through a spinneret, and a dry-jet wet spinning process is adopted. After coagulation and regeneration in a coagulation bath and drawing, a moisturizing and antioxidant Lyocell fiber is obtained.

2. The method for preparing the skin-emollient and antioxidant lyocell fiber according to claim 1, characterized in that: In step S1, the degree of polymerization of cellulose in the cellulose pulp is 600-800, the concentration of the N-methylmorpholine oxide aqueous solution is 75%-83%, and the swelling temperature is 80°C-90°C.

3. The method for preparing the skin-emollient and antioxidant lyocell fiber according to claim 1, characterized in that: In step S2, the vacuum degree after vacuuming is 0.05MPa-0.1MPa, and after dehydration, the concentration of N-methylmorpholine oxide in the swelling slurry is 87%-90%, and the dissolution temperature is 100°C-130°C.

4. The method for preparing the skin-emollient and antioxidant lyocell fiber according to claim 1, characterized in that: In step S3, the coagulation bath is an aqueous solution of N-methylmorpholine oxide, the temperature of the coagulation bath is 20° C. to 30° C., the concentration of N-methylmorpholine oxide in the coagulation bath is 15% to 25%, and the drafting multiple is 1.1 to 1.

3.

5. The method for preparing the skin-emollient and antioxidant lyocell fiber according to claim 1, characterized in that: In step S1, the antioxidant is selected from any one of epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, quercetin, naringenin, apigenin, and anthocyanin; the vegetable oil is selected from any one of camellia oil, olive oil, argan oil, jojoba oil, shea butter, and avocado oil; the polysaccharide is polymerized by β-1,4 glycosidic bonds, and the number average molecular weight of the polysaccharide is 120KD to 150KD.

6. The method for preparing the skin-emollient and antioxidant lyocell fiber according to claim 5, characterized in that: In step S1, the polysaccharide is selected from any one of sodium hyaluronate, alginate, konjac gum, xanthan gum and guar gum.

7. The method for preparing the skin-emollient and antioxidant lyocell fiber according to claim 6, characterized in that: The skin-emollient antioxidant is prepared by the following steps: A1. Dissolve 1 to 5 parts of antioxidant, 5 to 20 parts of vegetable oil, 1 to 5 parts of cholesterol, and 20 to 30 parts of Tween 20 in 80 to 100 parts of ethanol by weight, and mix thoroughly to obtain a first mixed solution; A2, slowly dripping 1 part of the first mixed solution into 1 part to 5 parts of deionized water, stirring at high speed for 1 hour to 2 hours, and then removing ethanol by rotary evaporation to obtain a vegetable oil modified antioxidant suspension; A3, dissolving 1 to 5 parts of the above vegetable oil modified antioxidant suspension and 5 to 10 parts of polysaccharide in 80 to 100 parts of deionized water, and stirring for 2 to 4 hours to obtain a second mixed solution; A4. Freeze the second mixed solution at -10°C to -20°C for 18 to 24 hours, and thaw at 15 to 25°C for 2 to 6 hours. Repeat the freezing and thawing steps for several times, and then vacuum dry the mixture at a vacuum degree of 0.1 to 1 Pa to obtain a skin moisturizing antioxidant.

8. The method for preparing the skin-emollient and antioxidant lyocell fiber according to claim 7, characterized in that: In step A4, the number of cycles is 5 to 10 times.

9. A skin-moisturizing and antioxidant lyocell fiber prepared by the preparation method according to any one of claims 1 to 8.

10. The skin-moistening and antioxidant lyocell fiber according to claim 9, characterized in that: The fiber has a fineness of 0.9-2.22 dtex, a dry breaking strength of 3.8-4.5 cN / dtex, and a wet breaking strength of 3.5-4.0 cN / dtex.

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