Skin-friendly and hypoallergenic composite functional fiber, and preparation method and application thereof

Abstract

This invention discloses a skin-friendly, hypoallergenic composite functional fiber, its preparation method, and its applications, relating to the field of functional textile materials technology. This invention utilizes transglutaminase (TG enzyme) to catalyze the formation of transamide covalent complex macromolecules from chitosan and gelatin, collagen, or collagen hydrolysates. These macromolecules are then blended with spinning dosing and introduced in situ into the fiber matrix through a spinning process. This ensures the functional components are uniformly distributed across the fiber cross-section and surface, forming a continuous, stable, and biocompatible skin-friendly protective film on the fiber surface. Through application, structural, and process innovations, this invention solves the problems of poor wash resistance, easy functional loss, and skin irritation in traditional hypoallergenic textiles. The resulting fiber exhibits long-lasting allergen adsorption, hypoallergenic skin-friendliness, antibacterial and soothing properties, and high wash resistance, making it suitable for intimate apparel, baby products, home textiles, and medical protective textiles.

Description

Technical Field

[0001] This invention relates to the field of functional textile materials, specifically to a skin-friendly, hypoallergenic composite functional fiber, its preparation method, and its application. Background Technology

[0002] In recent years, with the continuous expansion of the population with sensitive skin and allergies, the market demand for skin-friendly, low-irritant, and hypoallergenic textiles has increased rapidly. Currently, most hypoallergenic textiles on the market are given functionality through coatings, impregnation, and finishing processes. However, these treatments have significant shortcomings in practical applications: poor wash resistance, easy peeling of the functional layer after repeated washing leading to functional degradation; additionally, residual chemicals from the finishing process may become new allergens, increasing the risk of skin irritation or allergies; furthermore, the feel and breathability of the treated fabric are often affected, reducing wearing comfort. Therefore, how to improve the durability of functionality and the overall comfort of the fabric while ensuring skin-friendliness and hypoallergenic properties has become a pressing technical problem to be solved in this field.

[0003] Chitosan, a natural cationic polysaccharide, possesses excellent biocompatibility, antibacterial properties, and low allergenicity, and its application in fiber modification has been initially explored. However, chitosan exhibits significant drawbacks in fiber modification, including poor solubility, the need for acidic solvent processing, weak bonding with synthetic fiber matrices, insufficient wash resistance, damage to fiber mechanical properties and hand feel at high addition levels, and the risk of allergic reactions due to residual acid or cross-linking agents. These limitations restrict its direct application in skin-friendly and hypoallergenic fibers. Therefore, it is necessary to modify chitosan and apply the modified chitosan to in-situ composites, structural design, functional molding, and industrialization of textile fibers to directly meet the comprehensive requirements of high-end intimate textiles for durability, safety, and skin-friendliness. Summary of the Invention

[0004] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a skin-friendly and hypoallergenic composite functional fiber, its preparation method and application. Specifically, it provides a skin-friendly and hypoallergenic functional fiber based on TG enzyme-catalyzed chitosan-protein transamide bonding, its preparation method and application. This invention modifies chitosan to achieve green, efficient and stable modification, solving the safety problems of traditional chemical modification; and directly introduces the modified chitosan macromolecules into the spinning process, and through in-situ composite with textile fibers, prepares a structurally stable, durable, uncoated, and highly wash-resistant skin-friendly and hypoallergenic functional fiber, filling a technological gap in the industry and realizing a complete technology chain from raw material modification to functional fiber creation.

[0005] This invention utilizes transglutaminase (TG enzyme) to catalyze the transamidation reaction between chitosan and gelatin, collagen, or collagen hydrolysates, forming a stable, covalently bonded biocomposite macromolecule. This macromolecule is directly added to the spinning solution and, through processes such as melt spinning and wet spinning, is uniformly distributed within the fiber, forming a continuous and stable biocompatible protective film on the fiber surface. Compared with existing technologies, this invention has the following core differences: 1. Innovative application: Upgraded from "modified chitosan raw material" to "functional textile fiber." 2. Structural innovation: Functional components are distributed within the fiber body, not as a surface coating. 3. Process innovation: Integration of bonding reaction and spinning, in-situ composite in one step. 4. Functional innovation: Achieves long-lasting hypoallergenicity, allergen adsorption, and washability. 5. Application innovation: Targeting high-safety fields such as intimate apparel, infant and child products, medical applications, and home textiles.

[0006] The technical solution of the present invention is as follows: The first aspect of the present invention provides a skin-friendly, hypoallergenic composite functional fiber, characterized in that, The composite functional fiber includes a fiber matrix and chitosan-protein composite macromolecules uniformly distributed inside the fiber matrix. The chitosan-protein composite macromolecules form a continuous, dense, skin-friendly, low-allergenic bioprotective film on the fiber surface and surface region. The chitosan-protein composite macromolecule is formed by the covalent bonding of chitosan and protein through transamide bonds.

[0007] The composite functional fiber of this invention possesses the characteristics of allergen adsorption, hypoallergenic skin affinity, washability and durability, and biocompatibility. It can significantly reduce skin contact irritation and is suitable for the development of hypoallergenic textiles. The skin-friendly and hypoallergenic functional mechanism of this invention is as follows: 1. Chitosan is positively charged and can adsorb negatively charged allergens, dust mite metabolites, dander, and bacteria. 2. Collagen / gelatin is highly homologous to human skin, reducing friction, minimizing irritation, and enhancing skin affinity. 3. The covalent structure of transamide bonds is stable, washable, non-free, and does not detach. 4. A dense protective film forms on the fiber surface, sealing internal irritation sites and residual additives.

[0008] Optionally, the chitosan-protein composite macromolecule is formed by the covalent bonding of chitosan and protein through transamide bonds under the catalysis of glutamine transaminase; The protein includes at least one of gelatin, collagen, and collagen hydrolysate.

[0009] Optionally, the fiber matrix is ​​a blended spinning formed fiber matrix, including at least one of polyester, nylon, viscose fiber, lyocell, cellulose diacetate, cellulose triacetate, polyurethane, polyimide, and polyarylsulfone. The chitosan-protein composite macromolecules are introduced in situ into the fiber matrix through co-spinning, and after post-treatment, they are evenly distributed in the fiber cross-section and surface layer, forming a continuous, dense, skin-friendly, low-allergenic bioprotective film on the surface; the post-treatment includes stretching, washing, drying and heat setting.

[0010] A second aspect of the present invention provides a method for preparing the aforementioned composite functional fiber, comprising the following steps: S1. Dissolve chitosan in hydrochloric acid or dissolve chitosan hydrochloride in deionized water, adjust the pH to obtain a chitosan-based aqueous solution; add protein solution to the chitosan-based aqueous solution and mix evenly to obtain a mixture; add glutamine transaminase to the mixture to catalyze the reaction and obtain a transamidated chitosan-protein complex macromolecular solution. S2. The chitosan-protein composite macromolecular solution is blended with textile spinning matrix raw solution or melt to prepare a functionalized spinning solution; the functionalized spinning solution is spun to form nascent fibers; the nascent fibers are post-treated to form a stable skin-friendly and hypoallergenic protective film on the fiber surface by the chitosan-protein composite macromolecular solution, thereby obtaining skin-friendly and hypoallergenic composite functional fibers.

[0011] Optionally, in S1, the mass ratio of chitosan or chitosan hydrochloride to protein is 3-5:1, the amount of glutamine transaminase added is 0.5%-2.0% of the total mass of the mixture, the concentration of hydrochloric acid is 0.1-1.0 mol / L, the pH is adjusted to 4.0-6.2, the enzyme activity of the glutamine transaminase is 2000 U / g, the catalytic reaction is carried out at 25℃-85℃, and the catalytic reaction time is 1-48 hours.

[0012] Optionally, in S2, the spinning process is any one of melt spinning, wet spinning, dry spinning, solution spinning, and electrospinning.

[0013] Optionally, in S2, The specific method for melt spinning includes: preparing a chitosan-protein composite macromolecular solution into powder by freeze-drying or spray-drying; mixing fiber matrix chips in a specific ratio; granulating the mixture using a twin-screw extruder to prepare a functional masterbatch with a chitosan-protein composite macromolecular content of 20-30 wt%; mixing the functional masterbatch with fiber matrix chips at a mass ratio of 1:4 to 1:19; adding a bio-based emulsifier to obtain a spinning melt; and introducing the spinning melt into a melt spinning machine. The polyester melt temperature is controlled at 260~280℃, and the nylon melt temperature is controlled at 230~250℃. The melt is extruded through a spinneret with an orifice diameter of 0.2~0.4mm and 100~1000 orifices. The spinning speed is controlled at 100~300m / min. The extruded melt is rapidly cooled and shaped by cold air at 25~35℃ to obtain melt-spun nascent fibers. The nascent fibers are stretched, washed, dried, and heat-set to obtain skin-friendly and hypoallergenic composite functional fibers. The specific method of wet spinning includes: adding the degassed chitosan-protein composite macromolecular solution at a ratio of 5-15 wt% to the viscose / cellulose spinning solution at a uniform speed using an online addition method; blending at high speed for 10-20 minutes at a speed of 200-400 r / min to form a uniform and stable functionalized spinning solution; introducing the functionalized spinning solution into a wet spinning machine and extruding it through a spinneret with a pore size of 70-100 μm and 100-200 holes, controlling the spinning speed at 3-8 m / min; after passing through a 5-15 cm air section, the extruded spinning solution enters a coagulation bath to form wet-spun nascent fibers; stretching, washing, drying, and heat-setting the nascent fibers to obtain skin-friendly and hypoallergenic composite functional fibers. The specific method for dry spinning includes: mixing the degassed chitosan-protein composite macromolecular solution with cellulose acetate / polyurethane spinning dope at a ratio of 5-15 wt%, and adjusting the solid content of the mixed spinning solution to 10-20 wt% and the viscosity to 800-3000 mPa. The mixture is stirred at a constant temperature for 15-25 minutes at a rotation speed of 200-300 r / min to form a homogeneous and viscosity-stable functionalized spinning solution. The functionalized spinning solution is then introduced into a dry spinning machine and extruded through a spinneret with an orifice diameter of 0.1-0.3 mm and 50-100 orifices, with a spinning speed controlled at 5-15 m / min. The extruded spinning solution stream enters a hot air drying channel, where the channel temperature is controlled at 60-90℃ and the air velocity at 0.5-1.5 m / s, causing rapid solvent evaporation and fiber formation to obtain dry-spun nascent fibers. These nascent fibers are then stretched, washed, dried, and heat-set to obtain a skin-friendly, hypoallergenic composite functional fiber. The specific method for solution spinning includes: mixing the degassed chitosan-protein composite macromolecular solution with a polyimide / polysulfone spinning dope at a ratio of 5-15 wt%, adjusting the solid content to 8-18 wt% and the viscosity to 1000-4000 Pa. The solution is stirred and mixed at a low speed of 180-250 r / min for 20-30 min to form a uniform and stable functionalized spinning solution. The functionalized spinning solution is introduced into a solution spinning machine and extruded through a spinneret with an aperture of 0.08-0.2 mm and 50-100 holes, with the spinning speed controlled at 5-12 m / min. The extruded spinning solution stream passes through a nitrogen or argon inert gas protective layer with a length of 10-20 cm and a gas flow rate of 0.3-0.5 m / s, and then enters a coagulation bath where the solvent is extracted and the fiber is coagulated to obtain solution-spun nascent fiber. The nascent fiber is stretched, washed, dried, and heat-set to obtain a skin-friendly and hypoallergenic composite functional fiber.

[0014] A third aspect of the present invention provides the application of the composite functional fiber in the preparation of skin-friendly and hypoallergenic functional fabrics, wherein the skin-friendly and hypoallergenic functional fabrics include at least one of intimate apparel, infant textiles, home bedding, medical dressings, and hypoallergenic fabrics.

[0015] A fourth aspect of the present invention provides a skin-friendly and hypoallergenic functional fabric, which is prepared from the composite functional fiber or obtained from a fiber substrate through a finishing process.

[0016] Optionally, the finishing process includes a finishing agent method, in which the chitosan-protein composite macromolecules are fixed to the fiber surface by a crosslinking agent to form a water-resistant crosslinked network.

[0017] This invention has at least one of the following beneficial effects: 1. This invention utilizes transglutaminase (TG enzyme) to catalyze the formation of transamide covalent complex macromolecules from chitosan and gelatin, collagen, or collagen hydrolysate. These macromolecules are then blended with spinning solution and introduced in situ into the fiber matrix via spinning, resulting in a uniform distribution of functional components across the fiber cross-section and surface. This forms a continuous, stable, and biocompatible skin-friendly protective film on the fiber surface, solving problems such as poor wash resistance, easy functional loss, and skin irritation in traditional hypoallergenic textiles. The resulting fibers exhibit long-lasting allergen adsorption, hypoallergenic skin-friendliness, antibacterial and soothing properties, and high wash resistance, making them suitable for intimate apparel, baby products, home textiles, and medical protective textiles.

[0018] 2. The chitosan-protein composite macromolecules of the present invention are dispersed at the molecular level inside the fiber, and the functional components do not fall off, become free or become ineffective due to washing or friction; and the fiber can adsorb and fix dust mite allergens, pollen, dander and bacteria, and reduce skin contact irritation through a biological protective film, thus achieving hypoallergenic and anti-allergic functions; the fiber of the present invention maintains stable hypoallergenicity, skin affinity and allergen adsorption capacity after multiple washes. Detailed Implementation

[0019] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] This invention centers on the covalent bonding of chitosan with gelatin, collagen, or collagen hydrolysates catalyzed by transglutaminase (TG enzyme), forming a chitosan-protein complex macromolecule. This complex macromolecule is introduced in situ into the fiber matrix through blend spinning. Following post-treatments such as stretching, washing, drying, and heat setting, it is uniformly distributed across the fiber cross-section and surface, forming a continuous, dense, skin-friendly, and hypoallergenic bioprotective film on the surface. The entire process is compatible with existing textile industrial production lines, requiring no large-scale equipment modifications. The following sections, focusing on the preparation of the chitosan-protein complex macromolecule, describe the complete preparation processes of four methods: melt spinning, wet spinning, dry spinning, and solution spinning.

[0021] Example 1 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (I) Preparation of chitosan-gelatin protein complex macromolecular solution Take 100g of chitosan and dissolve it in 1.0mol / L hydrochloric acid; adjust the pH of the above solution to 5 with 0.1M NaOH solution, add 30g of gelatin protein that has been dissolved in deionized water in advance, stir thoroughly until the system is mixed evenly, then add 5g of TG enzyme with an activity of 2000U / g, control the temperature of the reaction system at 50℃, and catalyze the reaction at a constant temperature for 20 hours; After the reaction was completed, the pH of the reaction solution was adjusted to 6.8 again with 0.1M NaOH solution, and insoluble precipitates were removed by filtration. Subsequently, the reaction solution was desalted and concentrated using ultrafiltration or vacuum concentration: ultrafiltration was performed using a 20kDa molecular weight cutoff membrane at an operating pressure of 0.3MPa and at room temperature; vacuum concentration was performed at a vacuum level of -0.08MPa and a temperature of 40℃, followed by vacuum distillation to uniformly adjust the solid content of the reaction solution to 10wt%, yielding a concentrated chitosan-gelatin protein composite macromolecule solution. This concentrated solution was then degassed under vacuum at 50℃ for 3 hours to remove air bubbles, yielding a chitosan protein composite macromolecule concentrated solution for later use.

[0022] (II) Preparation of skin-friendly and hypoallergenic composite functional fibers by melt spinning Compatible substrates: thermoplastic polymers such as polyester (PET) and nylon (PA6 / PA66); Applicable to complex macromolecules: the chitosan-protein complex macromolecule concentrate prepared above; 1. Preparation of functionalized spinning melt: Preferred method (masterbatch method): The concentrated complex macromolecule solution obtained in Example 1 is freeze-dried or spray-dried to form a powder. This powder is mixed with polyester / nylon chips in a specific ratio and granulated using a twin-screw extruder to prepare a functional masterbatch with a chitosan protein complex macromolecule content of 25 wt%. This functional masterbatch is then mixed with matrix chips at a mass ratio of 1:9, resulting in a final composite macromolecule addition of 10 wt% in the spinning melt.

[0023] Alternative solution (online addition-deviation method): Use a twin-screw extruder with a high-efficiency degassing system. The degassed chitosan protein complex macromolecular concentrate is added at a ratio of 10 wt% through a precise metering pump into the mixing section of the twin-screw extruder. After rapid dehydration in the vacuum degassing zone of the extruder, it is thoroughly blended with the polyester / nylon melt to form a homogeneous and stable functionalized spinning melt.

[0024] In both of the above schemes, 0.2% of the total mass of the spinning melt is added as a bio-based emulsifier, which is a polyglycerol fatty acid ester, to improve the compatibility of the composite macromolecule with the melt.

[0025] 2. Melt spinning: The functionalized spinning melt is introduced into a melt spinning machine, with the polyester melt temperature controlled at 260℃ and the nylon melt temperature controlled at 230℃. The melt is extruded through a spinneret with a diameter of 0.4mm and 500 holes, and the spinning speed is controlled at 200m / min. The extruded melt is then rapidly cooled and shaped by 30℃ cold air to obtain melt-spun nascent fibers.

[0026] 3. Post-treatment of nascent fibers (1) Stretching: The nascent fibers are dry stretched at room temperature, and the stretching ratio is controlled at 2 times.

[0027] (2) Water washing: Deionized water gradient washing process is adopted, with water washing temperature successively 30℃→50℃→30℃, total water washing time 15min, water washing stretch ratio 1.2 times, to thoroughly remove residual additives and trace unreacted substances.

[0028] (3) Drying: Place the washed fibers in an 80℃ hot air drying device and dry for 60 minutes.

[0029] (4) Heat setting: The combined setting process of hot roller and hot air is adopted. The temperature of the hot roller is 100℃, the temperature of the hot air is 100℃, the setting time is 5 minutes, the winding speed is 8m / min, and the fiber structure is fixed.

[0030] (5) Finishing: After oiling, curling and cutting, polyester / nylon-based skin-friendly and hypoallergenic composite functional fiber products of different specifications are obtained.

[0031] Example 2 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (a) Preparation of chitosan-gelatin protein complex macromolecular solution: The preparation method is the same as in Example 1.

[0032] (II) Preparation of skin-friendly and hypoallergenic composite functional fibers by wet spinning Compatible matrices: Viscose fiber, Lyocell and other regenerated cellulose matrices; Applicable to complex macromolecules: the chitosan-protein complex macromolecule concentrate prepared above; 1. Preparation of functionalized spinning solution: The degassed chitosan protein composite macromolecular concentrate was added to the viscose / cellulose spinning solution at a constant speed using an online addition method at a ratio of 10wt%. The solution was then mixed at high speed at 300r / min for 15min to form a uniform and stable functionalized spinning solution.

[0033] 2. Wet spinning and forming: The functionalized spinning solution is introduced into a wet spinning machine and extruded through a spinneret with an 800μm pore size and 150 holes. The spinning speed is controlled at 5m / min. After passing through a 10cm air section, the extruded spinning solution enters the coagulation bath for forming. The viscose fiber is formed using a conventional acid bath with a mixed aqueous solution of 10wt% sulfuric acid and 20wt% sodium sulfate. To ensure that the chitosan protein complex macromolecules do not dissolve, a special coagulation bath for the lyocell or chitosan complex system (a mixture of chitosan-gelatin protein complex macromolecule concentrate and spinning solution, i.e., the spinning solution) is formed using a 6wt% sodium carbonate / sodium sulfate alkaline salt solution (pH 8.0~9.0). The temperature of all coagulation baths is controlled at 35℃ to obtain wet-spun nascent fibers.

[0034] 3. Post-treatment of nascent fibers (1) Stretching: The nascent fibers are stretched in steps, first by wet heat stretching at 50°C with a stretching ratio of 2.0 times, and then by hot stretching at 100°C with a stretching ratio of 1.3 times.

[0035] (2) Water washing: Deionized water gradient washing process is adopted, with water washing temperature successively 30℃→50℃→30℃, total water washing time 15min, water washing stretch ratio 1.4 times, to remove residual salt and additives in the system.

[0036] (3) Drying: Place the washed fibers in a 90℃ hot air drying device and dry for 30 minutes.

[0037] (4) Heat setting: The combined setting process of hot roller and hot air is adopted. The temperature of the hot roller is 100℃, the temperature of the hot air is 110℃, the setting time is 5s, and the winding speed is 8m / min. This promotes the enrichment of composite macromolecules on the fiber surface and forms a dense, skin-friendly, low-allergenic biological protective film.

[0038] (5) Finishing: After oiling, curling and cutting, viscose / cellulose-based skin-friendly and hypoallergenic composite functional fiber products of different specifications are obtained.

[0039] Example 3 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (a) Preparation of chitosan-gelatin protein complex macromolecular solution: The preparation method is the same as in Example 1.

[0040] (II) Dry spinning preparation of skin-friendly and hypoallergenic composite functional fibers Compatible matrices: Cellulose diacetate, cellulose triacetate, polyurethane, and other polymer matrices suitable for dry spinning. Applicable to complex macromolecules: the chitosan-protein complex macromolecule concentrate prepared above 1. Preparation of Functionalized Spinning Solution: The deaerated chitosan-protein composite macromolecular concentrate is mixed with cellulose acetate / polyurethane spinning solution at a ratio of 10 wt%. The solid content of the mixed spinning solution is adjusted to 15 wt%, and the viscosity to 2000 mPa. The mixture was stirred at a constant temperature for 20 minutes at a rotation speed of 250 r / min to form a uniform functionalized spinning solution with stable viscosity.

[0041] 2. Dry spinning forming: The functionalized spinning solution is introduced into a dry spinning machine and precisely delivered by a spinning metering pump. It is then extruded through a spinneret with 0.2mm orifice diameter and 580 orifices, with the spinning speed controlled at 10m / min. The extruded spinning solution stream enters a hot air drying channel, where the temperature is controlled at 80℃ and the air velocity at 1m / s. The solvent evaporates rapidly, and the fibers are formed, yielding dry-spun nascent fibers.

[0042] 3. Post-treatment of nascent fibers (1) Stretching: Low-temperature dry stretching is used for nascent fibers, with a stretching ambient temperature of 50℃ and a stretching ratio of 2.

[0043] (2) Washing: Use deionized water at room temperature for 10 minutes, with a water wash stretch ratio of 1.2 times, to remove trace amounts of residual organic solvent inside the fiber.

[0044] (3) Drying: Place the washed fibers in a 70℃ hot air drying device and dry at a low temperature for 50 minutes, while ensuring sufficient ventilation to ensure complete removal of solvent.

[0045] (4) Heat setting: The hot air setting process is adopted, with a setting temperature of 100℃, a setting time of 10s, and a winding speed of 8m / min to strengthen the bond between the composite macromolecule and the fiber matrix.

[0046] (5) Finishing: After oiling and winding, long filament products are obtained, or they can be cut into short fibers as needed.

[0047] Example 4 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (a) Preparation of chitosan-gelatin protein complex macromolecular solution: The preparation method is the same as in Example 1.

[0048] (II) Solution spinning preparation of skin-friendly and hypoallergenic composite functional fibers Compatible matrices: High-performance polymer matrices such as polyimide and polyarylsulfone that are dissolved in polar solvents. Applicable to complex macromolecules: the chitosan-protein complex macromolecule concentrate prepared above 1. Preparation of functionalized spinning solution: The deaerated chitosan protein composite macromolecular concentrate is mixed with polyimide / polysulfone spinning solution at a ratio of 5~15wt%, the solid content is adjusted to 8~18wt%, the viscosity is adjusted to 1000~4000Pa·s, and the mixture is stirred at low speed at 180~250r / min for 20~30min to form a uniform and stable functionalized spinning solution.

[0049] 2. Solution spinning: The functionalized spinning solution is introduced into a solution spinning machine and extruded through a spinneret with an aperture of 0.08~0.2mm and 50~100 holes. The spinning speed is controlled at 5~12m / min. The extruded spinning solution stream passes through a nitrogen or argon inert gas protective layer with a length of 10~20cm and a gas flow rate of 0.3~0.5m / s, and then enters a coagulation bath (such as a water bath or a specific solvent bath). The solvent is extracted, and the fiber coagulates to form the solution-spun nascent fiber.

[0050] 3. Post-treatment of nascent fibers (1) Stretching: Gradient temperature stretching is used for nascent fibers. First, they are stretched at a low temperature of 30~50℃ (stretching ratio 1.2~1.8 times), and then stretched at a medium temperature of 60~80℃ (stretching ratio 1.1~1.5 times).

[0051] (2) Washing: Deionized water is used for segmented washing. The washing temperature is 25℃→40℃→25℃, the total washing time is 15~20min, and the washing stretch ratio is 1.0~1.2 times to gently remove residual solvent from the fiber.

[0052] (3) Drying: Place the washed fibers in a vacuum drying oven and dry them at 50~70℃ for 50~70 minutes.

[0053] (4) Heat setting: Vacuum heat setting process is adopted, with a setting temperature of 80~110℃, a vacuum degree of -0.08~-0.1MPa, a setting time of 10~20s, and a winding speed of 5~7m / min to further fix the fiber structure and make the composite macromolecules form a stable skin-friendly protective film on the fiber surface.

[0054] (5) Finishing: After oiling, winding and cutting, polyimide / polysulfone-based skin-friendly and hypoallergenic composite functional fiber products of different specifications are obtained.

[0055] Example 5 This embodiment provides a skin-friendly and hypoallergenic functional fabric and its preparation method, including the following steps: (a) Preparation of chitosan-gelatin protein complex macromolecular solution: The preparation method is the same as in Example 1.

[0056] (ii) Finishing aid method to coat the fiber surface with chitosan-protein complex macromolecules Applicable substrates: Lyocell, cotton, viscose, polyester, nylon and other fabrics or short fibers; Applicable to complex macromolecules: the chitosan-protein complex macromolecule concentrate prepared above; (1) Preparation of additives The chitosan-protein composite macromolecular concentrate prepared above was diluted with deionized water to a solid content of 6 wt%. During the dilution process, 1.0 wt% of the penetrant fatty alcohol polyoxyethylene ether and 0.5 wt% of the crosslinking agent citric acid were added and stirred until completely dissolved. The pH was adjusted to 6 to obtain a uniform and stable functional finishing agent.

[0057] (2) Padding treatment The lyocell or other fiber fabrics are immersed in the above-mentioned functional finishing agent using a one-dip-one-pinch or two-dip-two-pinch process, with the immersion temperature at 20°C and the roll-off rate controlled at 80%.

[0058] (3) Pre-drying and baking The impregnated fabric is pre-dried at 100°C for 3 minutes, and then baked at 120°C for 3 minutes to cross-link the chitosan-protein composite macromolecules on the fiber surface to form a film.

[0059] (4) Washing and drying After baking, the fabric is washed three times with deionized water at room temperature to remove unfixed additives, and then dried and set at 100℃ to obtain a skin-friendly and hypoallergenic functional fabric with chitosan-protein composite macromolecules on the surface.

[0060] (5) Improved solution for high washability To further improve the wash resistance of finished fabrics and make them meet the wash resistance requirements, the following enhancements can be made based on the above formula and process: ① Improvement in the formulation of auxiliary agents: The chitosan-protein composite macromolecular concentrate was diluted to a solid content of 5 wt%, and 1 wt% of a penetrant fatty alcohol polyoxyethylene ether was added, introducing a dual crosslinking system: Crosslinking agent A (intermolecular crosslinking): 3.0 wt% nonionic aqueous blocked isocyanate; Crosslinking agent B (fiber-macromolecule anchoring): epoxy silane coupling agent GPTMS 1wt%; Catalyst / Crosslinking Promoter: Organotin catalyst (for isocyanate systems) 0.2wt.

[0061] Stir until completely dissolved, adjust pH to 6, and allow to stand to defoam to obtain a highly washable functional finishing agent.

[0062] ② Improvement of the dip-rolling process: The process employs a two-dip, two-roll process, with an immersion temperature of 20℃ and a roll-off rate of 80%.

[0063] ③ Improvement of baking process: Pre-dry at 100℃ for 5 minutes; then bake at 150℃ for 2 minutes to promote covalent bonding between the crosslinking agent and the fiber, forming a three-dimensional interpenetrating network structure.

[0064] ④ Post-processing improvements: After baking, the fabric is washed three times with deionized water at room temperature to remove unfixed additives, and then dried and set at 100℃.

[0065] After the above improvements, the finished fabric can withstand multiple standard washes (refer to GB / T 8629). After 2017, the surface protective film remained continuous and intact, and the skin irritation test results were not significantly different from those without water washing.

[0066] Example 6 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (I) Preparation of chitosan-collagen complex macromolecular solution: Take 100g of chitosan and dissolve it in 1.0mol / L hydrochloric acid; adjust the pH of the above solution to 5 with 0.1M NaOH solution, add 20g of collagen that has been dissolved in deionized water in advance, stir thoroughly until the system is mixed evenly, then add 5g of TG enzyme with an activity of 2000U / g, control the temperature of the reaction system at 60℃, and catalyze the reaction at a constant temperature for 20 hours; After the reaction was completed, the pH of the reaction solution was adjusted to 6.5 again with 0.1M NaOH solution, and insoluble precipitates were removed by filtration. Subsequently, the reaction solution was desalted and concentrated using ultrafiltration or vacuum concentration: ultrafiltration was performed using a 50kDa molecular weight cutoff membrane at an operating pressure of 0.2MPa and at room temperature; vacuum concentration was performed at a vacuum level of -0.08MPa and a temperature of 50℃, followed by vacuum distillation to uniformly adjust the solid content of the reaction solution to 10wt%, yielding a concentrated chitosan-collagen complex macromolecular solution. This concentrated solution was then degassed under vacuum at 50℃ for 3 hours to remove air bubbles, and was ready for use.

[0067] (II) Preparation of skin-friendly and hypoallergenic composite functional fibers by melt spinning: The preparation method is the same as in Example 1.

[0068] Example 7 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (a) Preparation of chitosan-collagen / collagen hydrolysate complex macromolecular solution: The preparation method is the same as in Example 6.

[0069] (II) Preparation of skin-friendly and hypoallergenic composite functional fibers by wet spinning: The preparation method is the same as in Example 2.

[0070] Example 8 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (a) Preparation of chitosan-collagen / collagen hydrolysate complex macromolecular solution: The preparation method is the same as in Example 6.

[0071] (II) Dry spinning preparation of skin-friendly and hypoallergenic composite functional fibers: The preparation method is the same as in Example 3.

[0072] Example 9 This embodiment provides a skin-friendly, hypoallergenic composite functional fiber and its preparation method, including the following steps: (a) Preparation of chitosan-collagen / collagen hydrolysate complex macromolecular solution: The preparation method is the same as in Example 6.

[0073] (II) Preparation of skin-friendly and hypoallergenic composite functional fibers by solution spinning: The preparation method is the same as in Example 4.

[0074] Example 10 This embodiment provides a skin-friendly and hypoallergenic functional fabric and its preparation method, including the following steps: (a) Preparation of chitosan-collagen / collagen hydrolysate complex macromolecular solution: The preparation method is the same as in Example 6.

[0075] (ii) Post-finishing agent method to coat the fiber surface with chitosan-protein complex macromolecules: Applicable substrates: Lyocell, cotton, viscose, polyester, nylon and other fabrics or short fibers Applicable to complex macromolecules: the chitosan-protein complex macromolecule concentrate prepared above. (1) Preparation of additives The chitosan-protein composite macromolecular concentrate prepared above was diluted with deionized water to a solid content of 6 wt%. During the dilution process, 1.0 wt% of the penetrant fatty alcohol polyoxyethylene ether and 0.5 wt% of the crosslinking agent nonionic waterborne polyurethane were added. The mixture was stirred until completely dissolved and the pH was adjusted to 6 to obtain a uniform and stable functional finishing agent.

[0076] (2) Padding treatment The lyocell or other fiber fabrics are immersed in the above-mentioned functional finishing agent using a one-dip-one-pinch or two-dip-two-pinch process, with the immersion temperature at 20°C and the roll-off rate controlled at 80%.

[0077] (3) Pre-drying and baking The impregnated fabric is pre-dried at 100°C for 3 minutes, and then baked at 120°C for 3 minutes to cross-link the chitosan-protein composite macromolecules on the fiber surface to form a film.

[0078] (4) Washing and drying After baking, the fabric is washed three times with deionized water at room temperature to remove unfixed additives, and then dried and set at 100℃ to obtain a skin-friendly and hypoallergenic functional fabric with chitosan-protein composite macromolecules on the surface.

[0079] (5) Improved solution for high washability To further improve the wash resistance of finished fabrics and make them meet the wash resistance requirements, the following enhancements can be made based on the above formula and process: ① Improvement in the formulation of auxiliary agents: The chitosan-protein composite macromolecular concentrate was diluted to a solid content of 5 wt%, and 1 wt% of a penetrant fatty alcohol polyoxyethylene ether was added, introducing a dual crosslinking system: Crosslinking agent A (intermolecular crosslinking): 2wt% of citric acid / sodium hypophosphite system (mass ratio 5:1); Crosslinking agent B (fiber-macromolecule anchoring): end groups are 1 wt% of NCO polyurethane prepolymer Catalyst / Crosslinking Promoter: Sodium hypophosphite (for citric acid system) 0.5wt.

[0080] Stir until completely dissolved, adjust pH to 6, and allow to stand to defoam to obtain a highly washable functional finishing agent.

[0081] ② Improvement of the dip-rolling process: The process employs a two-dip, two-roll process, with an immersion temperature of 20℃ and a roll-off rate of 80%.

[0082] ③ Improvement of baking process: Pre-dry at 100℃ for 5 minutes; then bake at 150℃ for 2 minutes to promote covalent bonding between the crosslinking agent and the fiber, forming a three-dimensional interpenetrating network structure.

[0083] ④ Post-processing improvements: After baking, the fabric is washed three times with deionized water at room temperature to remove unfixed additives, and then dried and set at 100℃.

[0084] After the above improvements, the finished fabric can withstand multiple standard washes (refer to GB / T 8629). After 2017, the surface protective film remained continuous and intact, and the skin irritation test results were not significantly different from those without water washing.

[0085] General instructions: 1. In the preparation of the above chitosan-protein complex macromolecular concentrate, the mass ratio of chitosan to gelatin protein, collagen or collagen hydrolysate can be adjusted to 3:1 to 5:1 according to the functional requirements of the fiber, and the amount of TG enzyme added can be flexibly controlled at 0.5 to 2.0% of the total mass of the mixed aqueous solution.

[0086] 2. The composite functional fibers prepared by the above five spinning processes all exhibit chitosan protein macromolecules dispersed at the molecular level or forming an interpenetrating network structure within the fiber matrix. Benefiting from this structural characteristic, the functional components are firmly bonded, and it is expected that after multiple standard water washes (refer to GB / T 8629), they will exhibit strong adhesion. Even after 2017, it still maintains its excellent skin-friendly, hypoallergenic, antibacterial, soothing, and allergen-absorbing properties.

[0087] The fibers prepared by different spinning processes of this invention are suitable for different application scenarios: melt-spun fibers are suitable for intimate apparel and bedding; wet-spun fibers are suitable for infant textiles and basic medical dressings; dry-spun fibers are suitable for high-end hypoallergenic underwear and elastic, skin-friendly fabrics; solution-spun fibers are suitable for high-performance medical protective textiles and high-temperature resistant, skin-friendly fabrics. The finishing agent method is suitable for finishing fabrics or short fibers such as lyocell, cotton, and viscose, with a simple process flow and strong equipment compatibility. After adopting the "high wash resistance improvement scheme," the wash resistance is significantly improved, making it suitable for the field of skin-friendly textiles that require high wash resistance and flexible processing.

[0088] The parameters of each spinning process can be reasonably fine-tuned according to the actual product specifications and production capacity requirements. All fine-tuned processes can achieve the core technical effects of this invention without requiring large-scale modifications to existing textile industrial production lines.

[0089] Tests and Results: The composite functional fibers prepared in Examples 1 to 10 were subjected to skin affinity and hypoallergenicity tests, and the test methods are as follows: (1) Skin affinity test: The test shall be conducted in accordance with the method in FZ / T 01166-2022 "Textile Fabric Touch Test and Evaluation Method Multi-index Integration Method".

[0090] (2) Hypoallergenicity test: The test shall be conducted in accordance with the method in GB 15979 "Hygienic requirements for disposable sanitary products".

[0091] The test results are shown in Table 1: Table 1 As can be seen from Table 1, compared with the matrix, the addition of chitosan-protein composite macromolecules to the matrix or the covering of the fabric with chitosan-protein composite macromolecules in this invention can effectively improve the skin-friendliness and hypoallergenicity of the fiber.

[0092] In summary, compared with existing technologies, this invention adds chitosan-protein composite macromolecules to the matrix to create a skin-friendly, hypoallergenic bio-protective film on the fiber surface. This film is non-coating, non-finishing, with functional components located inside the fiber, and its lifespan is the same as the fiber's. This invention utilizes TG enzyme catalysis and transamide covalent bonding, resulting in a wash-resistant, abrasion-resistant, and long-lasting stable function. It is a natural bio-based component, free of formaldehyde, fluorescent agents, and irritating residues, making it safe and hypoallergenic. It can be industrially mass-produced and is suitable for high-end intimate textiles, infant and toddler products, home textiles, and medical applications.

[0093] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A skin-friendly, hypoallergenic composite functional fiber, characterized in that, The composite functional fiber includes a fiber matrix and chitosan-protein composite macromolecules uniformly distributed inside the fiber matrix. The chitosan-protein composite macromolecules form a continuous, dense, skin-friendly, low-allergenic bioprotective film on the fiber surface and surface region. The chitosan-protein composite macromolecule is formed by the covalent bonding of chitosan and protein through transamide bonds.

2. The composite functional fiber according to claim 1, characterized in that, The chitosan-protein composite macromolecule is formed by the covalent bonding of chitosan and protein through transamide bonds under the catalysis of glutamine transaminase. The protein includes at least one of gelatin, collagen, and collagen hydrolysate.

3. The composite functional fiber according to claim 1, characterized in that, The fiber matrix is ​​a blended spinning formed fiber matrix, including at least one of polyester, nylon, viscose fiber, lyocell, cellulose diacetate, cellulose triacetate, polyurethane, polyimide, and polyarylsulfone. The chitosan-protein composite macromolecules are introduced in situ into the fiber matrix through co-spinning, and after post-treatment, they are evenly distributed in the fiber cross-section and surface layer, forming a continuous, dense, skin-friendly, low-allergenic bioprotective film on the surface; the post-treatment includes stretching, washing, drying and heat setting.

4. The method for preparing the composite functional fiber according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Dissolve chitosan in hydrochloric acid or dissolve chitosan hydrochloride in deionized water, adjust the pH to obtain a chitosan-based aqueous solution; add protein solution to the chitosan-based aqueous solution and mix evenly to obtain a mixture; add glutamine transaminase to the mixture to catalyze the reaction and obtain a transamidated chitosan-protein complex macromolecular solution. S2. The chitosan-protein composite macromolecular solution is blended with textile spinning matrix raw solution or melt to prepare a functionalized spinning solution; the functionalized spinning solution is spun to form nascent fibers; the nascent fibers are post-treated to form a stable skin-friendly and hypoallergenic protective film on the fiber surface by the chitosan-protein composite macromolecular solution, thereby obtaining skin-friendly and hypoallergenic composite functional fibers.

5. The preparation method according to claim 4, characterized in that, In S1, the mass ratio of chitosan or chitosan hydrochloride to protein is 3-5:

1. The amount of glutamine transaminase added is 0.5%-2.0% of the total mass of the mixture. The concentration of hydrochloric acid is 0.1-1.0 mol / L. The pH is adjusted to 4.0-6.

2. The enzyme activity of the glutamine transaminase is 2000 U / g. The catalytic reaction is carried out at 25℃-85℃ for 1-48 hours.

6. The preparation method according to claim 4, characterized in that, In S2, the spinning process is any one of melt spinning, wet spinning, dry spinning, solution spinning, and electrospinning.

7. The preparation method according to claim 6, characterized in that, In S2, The specific method for melt spinning includes: preparing a chitosan-protein composite macromolecular solution into powder by freeze-drying or spray-drying; mixing fiber matrix chips in a specific ratio; granulating the mixture using a twin-screw extruder to prepare a functional masterbatch with a chitosan-protein composite macromolecular content of 20-30 wt%; mixing the functional masterbatch with fiber matrix chips at a mass ratio of 1:4 to 1:19; adding a bio-based emulsifier to obtain a spinning melt; and introducing the spinning melt into a melt spinning machine. The polyester melt temperature is controlled at 260~280℃, and the nylon melt temperature is controlled at 230~250℃. The melt is extruded through a spinneret with an orifice diameter of 0.2~0.4mm and 100~1000 orifices. The spinning speed is controlled at 100~300m / min. The extruded melt is rapidly cooled and shaped by cold air at 25~35℃ to obtain melt-spun nascent fibers. The nascent fibers are stretched, washed, dried, and heat-set to obtain skin-friendly and hypoallergenic composite functional fibers. The specific method of wet spinning includes: adding the degassed chitosan-protein composite macromolecular solution at a ratio of 5-15 wt% to the viscose / cellulose spinning solution at a uniform speed using an online addition method; blending at high speed for 10-20 minutes at a speed of 200-400 r / min to form a uniform and stable functionalized spinning solution; introducing the functionalized spinning solution into a wet spinning machine and extruding it through a spinneret with a pore size of 70-100 μm and 100-200 holes, controlling the spinning speed at 3-8 m / min; after passing through a 5-15 cm air section, the extruded spinning solution enters a coagulation bath to form wet-spun nascent fibers; stretching, washing, drying, and heat-setting the nascent fibers to obtain skin-friendly and hypoallergenic composite functional fibers. The specific method for dry spinning includes: mixing the degassed chitosan-protein composite macromolecular solution with cellulose acetate / polyurethane spinning dope at a ratio of 5-15 wt%, and adjusting the solid content of the mixed spinning solution to 10-20 wt% and the viscosity to 800-3000 mPa. The mixture is stirred at a constant temperature for 15-25 minutes at a rotation speed of 200-300 r / min to form a homogeneous and viscosity-stable functionalized spinning solution. The functionalized spinning solution is then introduced into a dry spinning machine and extruded through a spinneret with an orifice diameter of 0.1-0.3 mm and 50-100 orifices, with a spinning speed controlled at 5-15 m / min. The extruded spinning solution stream enters a hot air drying channel, where the channel temperature is controlled at 60-90℃ and the air velocity at 0.5-1.5 m / s, causing rapid solvent evaporation and fiber formation to obtain dry-spun nascent fibers. These nascent fibers are then stretched, washed, dried, and heat-set to obtain a skin-friendly, hypoallergenic composite functional fiber. The specific method for solution spinning includes: mixing the degassed chitosan-protein composite macromolecular solution with a polyimide / polysulfone spinning dope at a ratio of 5-15 wt%, adjusting the solid content to 8-18 wt% and the viscosity to 1000-4000 Pa. The solution is stirred and mixed at a low speed of 180-250 r / min for 20-30 min to form a uniform and stable functionalized spinning solution. The functionalized spinning solution is introduced into a solution spinning machine and extruded through a spinneret with an aperture of 0.08-0.2 mm and 50-100 holes, with the spinning speed controlled at 5-12 m / min. The extruded spinning solution stream passes through a nitrogen or argon inert gas protective layer with a length of 10-20 cm and a gas flow rate of 0.3-0.5 m / s, and then enters a coagulation bath where the solvent is extracted and the fiber is coagulated to obtain solution-spun nascent fiber. The nascent fiber is stretched, washed, dried, and heat-set to obtain a skin-friendly and hypoallergenic composite functional fiber.

8. The application of the composite functional fiber according to any one of claims 1 to 3 in the preparation of skin-friendly and hypoallergenic functional fabrics, characterized in that, The skin-friendly and hypoallergenic functional fabrics include at least one of the following: intimate apparel, infant and children's textiles, home textile bedding, medical dressings, and hypoallergenic fabrics.

9. A skin-friendly, hypoallergenic functional fabric, characterized in that, It is prepared from the composite functional fiber described in any one of claims 1 to 3, or obtained from a fiber substrate through a finishing process.

10. The skin-friendly and hypoallergenic functional fabric according to claim 9, characterized in that, The finishing process includes a finishing agent method, in which the chitosan-protein composite macromolecules are fixed to the fiber surface by a crosslinking agent to form a water-resistant crosslinked network.

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