Modified natural fiber with anti-sensitivity function and preparation method thereof

Abstract

The invention belongs to the technical field of textiles, and particularly relates to a modified natural fiber with an anti-allergy function and a preparation method thereof. The preparation method of the modified natural fiber with the anti-sensitivity function comprises the following steps: washing the natural fiber with water, washing with ethanol, and finishing before etching by air plasma; carrying out beta-cyclodextrin graft modification; preparing a licorice extract ammonium salt solution from the licorice extract; adding the beta-cyclodextrin grafted and modified natural fibers into the licorice root extract ammonium salt solution; functional modification: adding a zinc compound solution for continuous adsorption and reaction to obtain functional modified natural fibers; and after-finishing to obtain the modified natural fiber with the anti-allergy function. The natural fiber is used as a raw material, and the natural fiber is modified by using the licorice extract and the zinc compound, so that the modified natural fiber with the anti-sensitivity function is obtained. The prepared functional modified natural fiber has good anti-allergy, anti-mite and antibacterial functions.

Description

Technical Field

[0001] This invention belongs to the field of textile technology, specifically relating to a modified natural fiber with soothing and desensitizing functions and its preparation method. Background Technology

[0002] Natural fibers, such as cotton, wool, silk, and linen, are widely used in textiles, medical, and hygiene fields due to their excellent breathability, moisture absorption, and biocompatibility. However, these fibers can also trigger skin allergies during actual use, especially for sensitive individuals, significantly impacting their quality of life. The link between allergic reactions and fibers and textiles is mainly reflected in the following three aspects: First, physical irritation from the fibers themselves, such as the surface structure of certain fibers (e.g., unprocessed wool scales), can directly rub against the skin, causing itching or discomfort; second, chemical sensitization, which is usually the most common cause of allergies, stemming from various chemical additives remaining during textile processing; and third, textiles, as "carriers" of allergens, easily attract or breed allergens such as mites and mold.

[0003] Traditional methods for reducing the allergenicity of fibers often rely on chemical finishing agents. While these methods can alleviate allergy problems to some extent, the chemicals used may pollute the environment and pose potential health risks with long-term use. Therefore, developing a green, safe, and efficient technology for modifying allergenic natural fibers is of significant practical importance and application value.

[0004] In existing technologies, some methods have emerged to enhance the performance of natural fibers through composite functional finishing. For example, Chinese invention patent CN106758216A discloses a method for treating antibacterial and UV-resistant cotton fabrics. The core of this method lies in sequentially treating the cotton fabric with a nonionic surfactant, chitosan quaternary ammonium salt, a natural antibacterial agent (including licorice extract), and a silver salt solution. The main goal is to achieve comprehensive antibacterial, UV-resistant, and wrinkle-resistant properties. Although the licorice extract itself has anti-inflammatory and anti-allergic potential, in this system, it is mainly used as an antibacterial agent and reducing agent, but its stability is poor. Furthermore, to obtain antibacterial properties, this method ultimately relies on the generation of nano-silver. Silver ions pose a potential risk of contact sensitization or ecotoxicity for people with sensitive skin. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a modified natural fiber with soothing and desensitizing functions, as well as its preparation method. This fiber uses natural fibers as raw materials, and modifies the natural fibers using licorice extract and zinc compounds to obtain the modified natural fiber with soothing and desensitizing functions. The prepared functional modified natural fiber exhibits excellent soothing, anti-mite, and antibacterial properties.

[0006] The method for preparing the modified natural fiber with soothing function according to the present invention includes the following steps: (1) Pre-treatment of natural fibers: First wash with water and then wash with ethanol. After drying, use air plasma to etch for later use. (2) Grafting modification: β-cyclodextrin is added to NaOH solution and mixed. The natural fiber treated in step (1) is added to the above solution and epichlorohydrin is added. After the reaction is completed, dehydration, wet opening, drying and fine opening are performed to obtain grafted modified natural fiber for later use. (3) Preparation of licorice extract ammonium salt solution: Dissolve licorice extract in water, add activated carbon for decolorization, filter, add ammonia water to the filtrate until no more precipitate is formed, collect the precipitate, dry it to obtain ammonium salt of licorice extract, dissolve it in ethanol solution to obtain licorice extract ammonium salt solution with a mass fraction of 15%~20%, for later use; (4) Functional modification: The grafted modified natural fiber obtained in step (2) is added to the licorice extract ammonium salt solution in step (3). After absorption, it is dehydrated and then zinc compound solution is added to continue absorption. After adsorption, the temperature is raised to 30~60℃ and the reaction time is 90~150min. After washing and dehydration, the functional modified natural fiber is obtained and set aside. (5) Finishing: The functionally modified natural fiber from step (4) is oiled, pressed, wet-opened, dried, and finely opened to obtain a modified natural fiber with soothing function.

[0007] In step (1), the pre-finishing water washing is performed at a temperature of 80-95℃ for 30-40 minutes. The natural fibers are first washed with water and then washed with ethanol, resulting in a moisture content of 50%-65% after drying. It is preferable to perform a dehydration once after water washing to a moisture content of 50%-60%, and then wash with an ethanol solution. The preferred ethanol solution has a mass fraction of 20%-30%, a temperature of 25-35℃, and an ethanol washing time of 10-20 minutes. Of course, for better results, the ethanol washing can be performed 2-3 times. After the ethanol washing, the fibers are washed with clean water until the pH of the washing water is neutral, and then dehydrated again until the moisture content is 50-65%, and then dried for later use. In step (1), both water washing and ethanol washing are mainly based on the complete immersion of the natural fibers in the solution. Of course, the more solution used, the cleaner the washing and the fewer times it is used. However, due to cost constraints, the amount used should be as small as possible, with the main goal of cleaning.

[0008] In step (1), the output power of air plasma etching is 250~300W, the pressure is 60~80Pa, and the processing time is 3~8min.

[0009] In step (1), the natural fiber is one of cotton fiber, linen fiber, silk fiber or wool fiber.

[0010] In step (2), the grafting modification involves adding β-cyclodextrin to a NaOH solution with a temperature of 45-50°C and a mass fraction of 18%-22% and mixing it. The natural fiber treated in step (1) is then added to the solution, with a bath ratio of 1:15-1:30. During step (2), stirring is preferred to accelerate the reaction, with a stirring speed of 300-400 r / min. After the reaction is completed, dehydration is performed, preferably to a concentration of 45%-65%.

[0011] In step (2), the mass ratio of grafted modified epichlorohydrin to β-cyclodextrin is 2:1 to 5:1, and preferably the reaction is carried out for 90 to 180 min after adding epichlorohydrin.

[0012] In step (3), during the preparation of the licorice extract ammonium salt solution, the licorice extract is dissolved in water at 80-90℃, wherein the mass fraction of the licorice extract is 15%-20%. In step (3), during decolorization, it is preferable to add an excess of activated carbon for heat preservation and decolorization, and the decolorization time is preferably 30-60 min. After filtration, ammonia water is added to the filtrate until no more precipitate is formed. The precipitate is collected and vacuum dried at 50-60℃.

[0013] In step (3), the ammonium salt of the licorice extract is preferably dissolved in an ethanol solution with a mass fraction of 80% to 95% at a temperature of 30 to 40°C to obtain a licorice extract ammonium salt solution with a mass fraction of 15% to 20%, which is then set aside.

[0014] In step (4), the functionally modified zinc compound is one or more of zinc sulfate, zinc nitrate, zinc chloride, zinc gluconate, zinc citrate, zinc lactate or zinc glycinate, and the mass fraction of the zinc compound solution is 10%~15%.

[0015] In step (4), the grafted modified natural fiber obtained in step (2) is preferably added to the licorice extract ammonium salt solution in step (3), and after absorption, it is dehydrated, with the water content after dehydration being 50%~60%.

[0016] In step (4), zinc compound solution is added to continue absorption. After adsorption is complete, the temperature is raised to 30~60℃ and the reaction time is 90~150min. The product is then washed with water and dehydrated. The water content after dehydration is 50%~65%, and the functionally modified natural fiber is obtained for later use.

[0017] In step (5), the oiling process involves mixing the oil agent GA and MGR-H at a mass ratio of 1:1~2, adjusting the pH to 6.0~6.9, adding the functionally modified natural fiber from step (4), with a bath ratio of 1:20~25, a temperature of 50~70℃, and a treatment time of 2~5 minutes.

[0018] In step (5), pressing is carried out using a high-pressure rolling mill, with a moisture content of 55% to 65%.

[0019] In step (5), the preferred solution for adjusting the pH in the oiling step is acetic acid and lactic acid.

[0020] In step (5), the drying step is preferably vacuum drying, with a drying temperature of 50~60℃, so that the moisture content is 6.5%~8.2%.

[0021] The modified natural fiber with soothing function is prepared by the aforementioned method.

[0022] The moisture content described in this invention is always measured as a mass percentage.

[0023] Preferably, the preparation method of the present invention consists of the following preparation process: (1) Pre-treatment of natural fibers: First wash with water at a temperature of 80~95℃ for 30~40min, then wash the natural fibers with ethanol, and after drying, the moisture content is 50%~65%. Then use air plasma for etching with an output power of 250~300W, a pressure of 60~80Pa, and a treatment time of 3~8min. (2) Grafting modification: β-cyclodextrin is added to a NaOH solution with a mass fraction of 18% to 22% at a temperature of 45 to 50°C and mixed. The natural fiber treated in step (1) is added to the above solution with a bath ratio of 1:15 to 1:30. Epichlorohydrin is then added to make the mass ratio of epichlorohydrin to β-cyclodextrin 2:1 to 5:1. After the reaction is completed, dehydration, wet opening, drying, and fine opening are performed to obtain grafted modified natural fiber for later use. (3) Preparation of licorice extract ammonium salt solution: Dissolve licorice extract in water at 80~90℃, add activated carbon for decolorization, filter, add ammonia water to the filtrate until no more precipitate is formed, collect the precipitate, dry it to obtain ammonium salt of licorice extract, dissolve it in ethanol solution to obtain licorice extract ammonium salt solution with a mass fraction of 15%~20%, for later use. (4) Functional modification: The grafted modified natural fiber obtained in step (2) is added to the licorice extract ammonium salt solution in step (3). After absorption, it is dehydrated and then added to a zinc compound solution with a mass fraction of 10%~15% for continued absorption. After adsorption, the temperature is raised to 30~60℃ and the reaction time is 90~150min. The fiber is washed with water and dehydrated to obtain the functional modified natural fiber for later use. (5) Finishing: Mix the oil agent GA and MGR-H at a mass ratio of 1:1~2, then adjust the pH to 6.0~6.9, add the functional modified natural fiber from step (4), the bath ratio is 1:20~25, the temperature is 50~70℃, the treatment time is 2~5min, the high pressure rolling mill is used, the moisture content is 55%~65%, wet opening, drying, fine opening, to obtain the modified natural fiber with soothing function.

[0024] Specifically, the preparation method of the modified natural fiber with soothing function includes the following steps: 1. Pre-treatment of natural fibers The natural fibers are washed in deionized water at 80-95℃ for 30-40 minutes with continuous stirring to remove impurities from the surface of the natural fibers. Then, they are dehydrated by pressing or centrifugation until the moisture content is 50%-60%. The natural fibers are one of cotton, linen, silk, or wool fibers.

[0025] Then, the natural fibers after the above washing treatment are washed with an ethanol solution with a mass fraction of 20%~30% and a temperature of 25~35℃ for 10~20 minutes to remove lipid impurities on the surface of the natural fibers. After washing with ethanol solution 2~3 times, the ethanol on the surface of the fibers is washed with deionized water to make its pH value neutral. Then, it is dehydrated again to make its moisture content 50%~65%, and then dried for later use.

[0026] After the natural fibers that have undergone the above washing treatment are dried, they are etched using air plasma with an output power of 250~300W, a pressure of 60~80Pa, and a treatment time of 3~8min. During the plasma treatment, the fibers are continuously rotated, thereby etching the surface of the natural fibers to increase their surface area. At the same time, the number of oxygen-containing groups on the natural fibers, such as hydroxyl and carboxyl groups, increases, enhancing the water absorption of the natural fibers and increasing the number of reactive groups.

[0027] 2. Grafting modification β-Cyclodextrin was added to a NaOH solution with a mass fraction of 18%–22% at a temperature of 45–50°C and stirred at a stirring speed of 300–400 r / min. After the β-cyclodextrin was completely dissolved, the natural fiber prepared in step 1 was added at a bath ratio of 1:15–1:30. Then, epichlorohydrin was slowly added at a mass ratio of 2:1–5:1 to β-cyclodextrin. The reaction time was 90–180 min. After the reaction, the fiber was dehydrated to a moisture content of 45%–65%. The fiber was then wet-opened, dried, and fine-opened to obtain β-cyclodextrin-grafted modified natural fiber for later use. Grafting the fiber with β-cyclodextrin improved the adsorption capacity and adsorption stability of the subsequent natural fiber.

[0028] 3. Preparation of licorice extract ammonium salt solution Licorice extract was dissolved in deionized water at 80-90℃, with a mass fraction of 15%-20%. After dissolution, activated carbon was added at a mass ratio of 4-6 times that of the licorice extract in the solution for heat preservation and decolorization for 30-60 minutes. The solution was filtered to obtain a decolorized filtrate containing licorice extract. Ammonia was then added to the filtrate, resulting in the formation of a precipitate. Ammonia was added until no more precipitate was formed. The precipitate was collected after filtration and dried under vacuum at 50-60℃ to obtain the ammonium salt of licorice extract.

[0029] The ammonium salt of the licorice extract prepared above was dissolved in an ethanol solution with a mass fraction of 80% to 95% at a temperature of 30 to 40°C, wherein the mass fraction of the ammonium salt of the licorice extract was 15% to 20%.

[0030] 4. Functional modification The prepared β-cyclodextrin-grafted modified natural fiber was added to a prepared licorice extract ammonium salt solution at a bath ratio of 1:15 to 1:30 for full adsorption over 40 to 60 minutes. After adsorption, the fiber was dehydrated to a moisture content of 50% to 60%. Then, it was added to a zinc compound solution for further adsorption at a bath ratio of 1:15 to 1:30 for another 40 to 60 minutes. The zinc compound solution was one or more of zinc sulfate, zinc nitrate, zinc chloride, zinc gluconate, zinc citrate, zinc lactate, or zinc glycinate, with a mass fraction of 10% to 15%. After adsorption, further dehydration was performed to a moisture content of 50% to 60%. The fiber was then heated to 30 to 60°C for a reaction time of 90 to 150 minutes to allow the adsorbed licorice extract ammonium salt and zinc compound to fully react and generate zinc glycyrrhizinate. Finally, the fiber was washed and dehydrated to a moisture content of 50% to 65%. By utilizing the adsorption and protective effects of the β-cyclodextrin cavity, as well as the reaction of the active ingredients (licorice extract ammonium salt and zinc compounds) within the β-cyclodextrin cavity, the stability and durability of the structure are improved.

[0031] 5. Post-processing The fibers prepared in step 4 are oiled. Oil agent GA and MGR-H (purchased from Takemoto Co., Ltd., Japan) are mixed at a mass ratio of 1:1~2 to form an emulsion with a concentration of 5.0~8.0 g / L. Acetic acid or lactic acid is added to adjust the pH to 6.0~6.9 to obtain the oiling emulsion. The fibers prepared in step 4 are then added to the above oiling emulsion at a bath ratio of 1:20~25. The temperature is 50~70℃, and the treatment time is 2~5 minutes, making the fibers weakly acidic. High-pressure rolling is used to achieve a moisture content of 55%~65%, followed by wet opening. Vacuum drying is then performed at a temperature of 50~60℃ to achieve a fiber moisture content of 6.5%~8.2%. Fine opening is then performed to obtain modified natural fibers with soothing and desensitizing functions.

[0032] Compared with the prior art, the beneficial effects of the present invention are: (1) The modified natural fiber of the present invention firstly cleans and increases the surface area of ​​the natural fiber by washing and finishing and plasma treatment, while increasing the number of oxygen-containing groups such as hydroxyl and carboxyl groups on the natural fiber, thereby enhancing the water absorption of the natural fiber and increasing the number of reactive groups.

[0033] (2) By grafting β-cyclodextrin with natural fiber, this invention not only improves the stability of the structure, but also increases the adsorption of functional components and protects the effective components after subsequent molding, thereby improving adsorption and functional stability.

[0034] (3) In this invention, licorice extract is decolorized to avoid affecting the color properties of the fiber, and then ammonia is added to react and obtain ammonium salt of licorice extract. By utilizing the fiber to adsorb the ammonium salt solution of licorice extract and the zinc compound solution in sequence, the active ingredients are evenly distributed in the fiber. By adjusting the reaction conditions, the ammonium salt of licorice extract and zinc compound react, so that the final functional substances are evenly distributed in the fiber, making the functionality more stable.

[0035] (4) The modified natural fiber of the present invention has good anti-allergic and antibacterial functions, with an inhibition rate of ≥81.6% against Escherichia coli, ≥82.1% against Staphylococcus aureus, and ≥80.3% against Candida albicans; a mite repellency rate of ≥85%; a mildew resistance level of ≥1; and a pH value of 6.0~6.9, which is consistent with the weak acidity of human skin. After 20 washes, the inhibition rate against Escherichia coli is ≥80.9%, the inhibition rate against Staphylococcus aureus is ≥81.2%, and the inhibition rate against Candida albicans is ≥80.0%; the mite repellency rate is ≥83.9%; the mildew resistance level of the fiber is ≥1; and the pH value of the fiber is 6.3~7.0, with good wash resistance. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments.

[0037] The licorice extract used below was purchased from Shaanxi Xintianyu Biotechnology Co., Ltd.

[0038] The following oils, GA and MGR-H, were purchased from Takemoto Corporation of Japan.

[0039] The following antibacterial rates are calculated using GB / T20944.3-2008 "Evaluation of Antibacterial Properties of Textiles" Part 3: Shaking Method). The mite repellency rate was evaluated according to GB / T24253-2009 "Evaluation of the anti-mite performance of textiles"). The mildew resistance level was tested using the petri dish method in GB / T 24346-2009 "Evaluation of Mildew Resistance Performance of Textiles"; The washing method for 20 washes follows the washing conditions and procedures in GB / T 8629-2017 "Home Washing and Drying Procedures for Textile Testing".

[0040] Example 1 The method for preparing the modified natural fiber with soothing function according to the present invention includes the following steps: 1. Pretreatment of natural fibers The natural fiber was washed in deionized water at 80°C for 40 minutes with continuous stirring to remove impurities from the surface of the natural fiber. Then, it was dehydrated by pressing or centrifugation until the moisture content was 60%. The natural fiber was cotton fiber.

[0041] Then, the natural fibers after the above washing treatment are washed with an ethanol solution with a mass fraction of 20% and a temperature of 35°C for 10 minutes to remove lipid impurities on the surface of the natural fibers. After washing with ethanol solution three times, the ethanol on the surface of the fibers is washed with deionized water to make its pH value neutral. Then, it is dehydrated again to make its moisture content 65% and dried for later use.

[0042] After the natural fibers that have undergone the above washing treatment are dried, they are etched using air plasma with an output power of 250W, a pressure of 60Pa, and a processing time of 3min. The fibers are continuously turned over during the plasma treatment process.

[0043] 2. β-Cyclodextrin grafted and modified natural fibers β-Cyclodextrin was added to a 22% NaOH solution at 45°C and stirred at 300 r / min until completely dissolved (β-cyclodextrin mass fraction was 8%). The natural fibers prepared in step 1 were then added at a bath ratio of 1:15. Epichlorohydrin was then slowly added at a mass ratio of 2:1 (epoxychlorohydrin to β-cyclodextrin), and the reaction was carried out for 90 min. After the reaction, dehydration was performed, and the moisture content after dehydration was 65%. The fibers were then subjected to wet opening, drying, and fine opening to obtain β-cyclodextrin-grafted modified natural fibers for later use.

[0044] 3. Preparation of licorice extract ammonium salt solution Licorice extract was dissolved in deionized water at 80°C, with a mass fraction of 15%. After dissolution, activated carbon was added at a mass ratio of 4 times that of the licorice extract in the solution. The mixture was kept at this temperature for 30 minutes to decolorize. After filtration, a filtrate containing licorice extract was obtained. Ammonia was then added to the filtrate, resulting in the formation of a white precipitate. Ammonia was continued to be added until no more precipitate was formed. The precipitate was collected after filtration and dried under vacuum at 50°C to obtain the ammonium salt of licorice extract.

[0045] The ammonium salt of the licorice extract prepared above was dissolved in an ethanol solution with a mass fraction of 80% at a temperature of 30°C, wherein the mass fraction of the ammonium salt of the licorice extract was 15%.

[0046] 4. Functional modification of natural fibers by β-cyclodextrin grafting The prepared β-cyclodextrin-grafted modified natural fibers were added to the prepared licorice extract ammonium salt solution at a bath ratio of 1:15 for 40 minutes to allow for full adsorption. After adsorption, the fibers were dehydrated to a moisture content of 60%. Then, a zinc compound solution (zinc sulfate, 10% by mass) was added for further adsorption at a bath ratio of 1:15 for another 40 minutes. After adsorption, dehydration continued to the point where the fiber moisture content was 60%. The fiber was then heated to 30°C for 90 minutes to allow the licorice extract ammonium salt and zinc compound to react fully, generating zinc glycyrrhizinate. Finally, the fibers were washed and dehydrated to a moisture content of 65%.

[0047] 5. Finishing of fiber preparation The fibers prepared in step 4 are oiled. The oiling agent GA and MGR-H are mixed at a mass ratio of 1:2 to form an oiling emulsion with a concentration of 5.0 g / L. Lactic acid is added to adjust the pH value to 6.0. Then, the fibers prepared in step 4 are added to the above emulsion at a bath ratio of 1:20. The temperature is 50℃ and the treatment time is 5 min to make the fibers weakly acidic. High-pressure rolling is used to achieve a moisture content of 65%. Wet opening is performed, followed by vacuum drying at a drying temperature of 50℃ to achieve a fiber moisture content of 8.2%. Fine opening is then performed to obtain modified natural fibers with soothing and desensitizing functions.

[0048] The modified natural fiber with soothing function prepared in Example 1 exhibits good anti-allergic and antibacterial properties, with an inhibition rate of 81.6% against Escherichia coli, 82.1% against Staphylococcus aureus, and 80.3% against Candida albicans; a mite repellency rate of 85%; a mildew resistance grade of 1; and a pH value of 6.0, consistent with the slightly acidic nature of human skin, providing good health benefits. After 20 washes, the inhibition rate against Escherichia coli remained at 80.9%, against Staphylococcus aureus at 81.2%, and against Candida albicans at 80.0%; the mite repellency rate was 83.9%; the mildew resistance grade was 1; and the pH value was 6.3.

[0049] Example 2 The method for preparing the modified natural fiber with soothing function according to the present invention includes the following steps: 1. Pre-treatment of natural fibers The natural fiber was washed in deionized water at 86°C for 35 minutes with continuous stirring to remove impurities from the surface of the natural fiber. It was then dehydrated by pressing until the moisture content reached 55.3%. The natural fiber was hemp fiber.

[0050] Then, the natural fibers after the above washing treatment are washed with an ethanol solution with a mass fraction of 25.2% and a temperature of 30.5℃ for 15 minutes to remove lipid impurities on the surface of the natural fibers. After washing with ethanol solution three times, the ethanol on the surface of the fibers is washed with deionized water to make its pH value neutral. Then, it is dehydrated again to make its moisture content 55.6% and dried for later use.

[0051] After the natural fibers that have undergone the above washing treatment are dried, they are etched using air plasma with an output power of 275W, a pressure of 70Pa, and a processing time of 5min. The fibers are continuously turned over during the plasma treatment.

[0052] 2. β-Cyclodextrin grafted and modified natural fibers β-Cyclodextrin was added to a 19.8% NaOH solution at 46.9℃ and stirred at 355 r / min until completely dissolved (β-cyclodextrin mass fraction was 9%). The natural fibers prepared in step 1 were then added at a bath ratio of 1:22. Epichlorohydrin was then slowly added at a mass ratio of 3:1 to β-cyclodextrin, and the reaction time was 130 min. After the reaction, dehydration was performed, and the moisture content after dehydration was 55.3%. The fibers were then subjected to wet opening, drying, and fine opening to obtain β-cyclodextrin-grafted modified natural fibers for later use.

[0053] 3. Preparation of licorice extract ammonium salt solution Licorice extract was dissolved in deionized water at 85°C, with a mass fraction of 18.1%. After dissolution, activated carbon was added at a mass ratio of 5 times that of the licorice extract in the solution. The solution was then kept warm for decolorization for 45 minutes. After filtration, a filtrate containing licorice extract was obtained. Ammonia was then added to the filtrate, resulting in the formation of a white precipitate. Ammonia was added continuously until no more precipitate was formed. The precipitate was collected after filtration and dried under vacuum at 55°C to obtain the ammonium salt of licorice extract.

[0054] The ammonium salt of the licorice extract prepared above was dissolved in an ethanol solution with a mass fraction of 89% at a temperature of 35°C, wherein the mass fraction of the ammonium salt of the licorice extract was 18.2%.

[0055] 4. Functional modification of natural fibers by β-cyclodextrin grafting The prepared β-cyclodextrin-grafted modified natural fibers were added to the prepared licorice extract ammonium salt solution at a bath ratio of 1:20 for 50 minutes to allow for complete adsorption. After adsorption, the fibers were dehydrated to a moisture content of 55.2%. Then, a zinc compound solution (zinc nitrate with a mass fraction of 12.6%) was added for further adsorption at a bath ratio of 1:22 for 50 minutes. After adsorption, dehydration continued, resulting in a fiber moisture content of 57.5%. The fibers were then heated to 45.2°C for 120 minutes to allow for complete reaction between the licorice extract ammonium salt and the zinc compound, generating zinc glycyrrhizinate. Finally, the fibers were washed and dehydrated to a moisture content of 56.8%.

[0056] 5. Finishing of fiber preparation The fibers prepared in step 4 were oiled. GA and MGR-H were mixed at a mass ratio of 1:1 to form an oiling emulsion with a concentration of 6.5 g / L. Acetic acid was added to adjust the pH to 6.5. The fibers prepared in step 4 were then added to the oiling emulsion at a bath ratio of 1:22. The temperature was 61.2℃, and the treatment time was 3.5 min, making the fibers weakly acidic. High-pressure rolling was used to achieve a moisture content of 60.5%. Wet opening was performed, followed by vacuum drying at 55℃ to reduce the fiber moisture content to 7.5%. Fine opening was then performed to obtain modified natural fibers with soothing and calming functions.

[0057] The modified natural fiber with soothing function prepared in Example 2 exhibits good anti-allergic and antibacterial properties, with an inhibition rate of 86.3% against Escherichia coli, 87.1% against Staphylococcus aureus, and 85.2% against Candida albicans; a mite repellency rate of 88.5%; a mildew resistance rating of Grade 1; and a pH value of 6.5, which matches the slightly acidic nature of human skin, providing good health benefits. After 20 washes, the inhibition rate against Escherichia coli remained at 86.0%, against Staphylococcus aureus at 86.3%, and against Candida albicans at 84.3%; the mite repellency rate was 86.9%; the mildew resistance rating was Grade 1; and the pH value was 6.6.

[0058] Example 3 The method for preparing the modified natural fiber with soothing function according to the present invention includes the following steps: 1. Pretreatment of natural fibers The natural fibers were washed in deionized water at 90°C for 35 minutes with continuous stirring to remove impurities from the surface of the fibers. They were then centrifuged to remove water until the moisture content reached 52.5%. The natural fibers were cotton fibers.

[0059] Then, the natural fibers after the above washing treatment are washed with an ethanol solution with a mass fraction of 27.2% and a temperature of 27.5°C for 18 minutes to remove lipid impurities from the surface of the natural fibers. After washing with ethanol solution three times, the ethanol on the surface of the fibers is washed with deionized water to make its pH value neutral. Then, it is dehydrated again to make its moisture content 53.1% and dried for later use.

[0060] After the natural fibers that have undergone the above washing treatment are dried, they are etched using air plasma with an output power of 300W, a pressure of 75Pa, and a processing time of 6 minutes. The fibers are continuously turned over during the plasma treatment process.

[0061] 2. β-Cyclodextrin grafted and modified natural fibers β-Cyclodextrin was added to a 19.1% NaOH solution at 48.2℃ and stirred at 380 r / min until completely dissolved, resulting in a β-cyclodextrin mass fraction of 9.2%. The natural fibers prepared in step 1 were then added at a bath ratio of 1:25. Epichlorohydrin was then slowly added at a mass ratio of 4:1 to β-cyclodextrin, and the reaction time was 150 min. After the reaction, dehydration was performed, resulting in a moisture content of 51.9%. The fibers were then subjected to wet opening, drying, and fine opening to obtain β-cyclodextrin-grafted modified natural fibers for later use.

[0062] 3. Preparation of licorice extract ammonium salt solution Licorice extract was dissolved in deionized water at 87.5℃, with a mass fraction of 18.6%. After dissolution, activated carbon was added at a mass ratio of 6 times that of the licorice extract in the solution, and the mixture was kept at this temperature for 55 minutes for decolorization. The solution was then filtered to obtain a decolorized filtrate containing licorice extract. Ammonia was then added to the filtrate, resulting in the formation of a white precipitate. Ammonia was continued to be added until no more precipitate was formed. The precipitate was collected after filtration and dried under vacuum at 57.2℃ to obtain the ammonium salt of licorice extract.

[0063] The ammonium salt of the licorice extract prepared above was dissolved in an ethanol solution with a mass fraction of 92% at a temperature of 37.0℃, wherein the mass fraction of the ammonium salt of the licorice extract was 18.6%.

[0064] 4. Functional modification of natural fibers by β-cyclodextrin grafting The prepared β-cyclodextrin-grafted modified natural fibers were added to the prepared licorice extract ammonium salt solution at a bath ratio of 1:25 for full adsorption over 52 minutes. After adsorption, the fibers were dehydrated to a moisture content of 52.5%. Then, a zinc compound solution (zinc lactate with a mass fraction of 13.2%) was added for further adsorption over a bath ratio of 1:25 for 55 minutes. After adsorption, dehydration continued, resulting in a fiber moisture content of 53.2%. The fibers were then heated to 57°C for a reaction time of 130 minutes to allow for complete reaction between the licorice extract ammonium salt and the zinc compound, generating zinc glycyrrhizinate. Finally, the fibers were washed and dehydrated to a moisture content of 52.3%.

[0065] 5. Finishing of fiber preparation The fibers prepared in step 4 were oiled. GA and MGR-H were mixed at a mass ratio of 1:1.8 to form an oiling emulsion with a concentration of 7.0 g / L. Acetic acid was added to adjust the pH to 6.8. The fibers prepared in step 4 were then added to the oiling emulsion at a bath ratio of 1:24. The temperature was 67.5℃, and the treatment time was 2.5 min, making the fibers weakly acidic. High-pressure rolling was used to achieve a moisture content of 56.5%. Wet opening was performed, followed by vacuum drying at 57.2℃ to achieve a fiber moisture content of 6.9%. Fine opening was then performed to obtain modified natural fibers with soothing and calming functions.

[0066] The modified natural fiber with soothing function prepared in Example 3 exhibits good anti-allergic and antibacterial properties, with an inhibition rate of 90.8% against Escherichia coli, 92.3% against Staphylococcus aureus, and 91.5% against Candida albicans; a mite repellency rate of 91.6%; a mildew resistance rating of 0; and a pH value of 6.8, which matches the slightly acidic nature of human skin, providing good health benefits. After 20 washes, the inhibition rate against Escherichia coli remained at 90.1%, against Staphylococcus aureus at 91.2%, and against Candida albicans at 90.6%; the mite repellency rate was 89.9%; the mildew resistance rating was 0; and the pH value was 6.9.

[0067] Example 4 The method for preparing the modified natural fiber with soothing function according to the present invention includes the following steps: 1. Pretreatment of natural fibers The natural fiber was washed in deionized water at 95°C for 30 minutes with continuous stirring to remove impurities from the surface of the natural fiber. Then, it was centrifuged to remove water until the moisture content was 50%. The natural fiber was wool fiber.

[0068] Then, the natural fibers after the above washing treatment are washed with an ethanol solution with a mass fraction of 30% and a temperature of 25°C for 20 minutes to remove lipid impurities on the surface of the natural fibers. After washing twice with the ethanol solution, the ethanol on the surface of the fibers is washed with deionized water to make its pH value neutral. Then, it is dehydrated again to make its moisture content 50% and dried for later use.

[0069] After the natural fibers that have undergone the above washing treatment are dried, they are etched using air plasma with an output power of 300W, a pressure of 80Pa, and a processing time of 8min. The fibers are continuously turned over during the plasma treatment process.

[0070] 2. β-Cyclodextrin grafted and modified natural fibers β-Cyclodextrin was added to an 18% NaOH solution at 50°C and stirred at 400 r / min until completely dissolved (β-cyclodextrin mass fraction was 10%). The natural fibers prepared in step 1 were then added at a bath ratio of 1:30. Epichlorohydrin was then slowly added at a mass ratio of 5:1 (epoxychlorohydrin to β-cyclodextrin), and the reaction was carried out for 180 min. After the reaction, dehydration was performed, and the moisture content after dehydration was 50%. The fibers were then subjected to wet opening, drying, and fine opening to obtain β-cyclodextrin-grafted modified natural fibers for later use.

[0071] 3. Preparation of licorice extract ammonium salt solution Licorice extract was dissolved in deionized water at 90°C, with a mass fraction of 20%. After dissolution, activated carbon was added at a mass ratio of 6 times that of the licorice extract in the solution. The mixture was kept at this temperature for 60 minutes to decolorize. After filtration, a filtrate containing licorice extract was obtained. Ammonia was then added to the filtrate, resulting in the formation of a white precipitate. Ammonia was continued to be added until no more precipitate was formed. The precipitate was collected after filtration and dried under vacuum at 60°C to obtain the ammonium salt of licorice extract.

[0072] The ammonium salt of the licorice extract prepared above was dissolved in an ethanol solution with a mass fraction of 95% at a temperature of 40°C, wherein the mass fraction of the ammonium salt of the licorice extract was 20%.

[0073] 4. Functional modification of natural fibers by β-cyclodextrin grafting The prepared β-cyclodextrin-grafted modified natural fibers were added to the prepared licorice extract ammonium salt solution at a bath ratio of 1:30 for 60 minutes to allow for complete adsorption. After adsorption, the fibers were dehydrated to a moisture content of 50%. Then, a zinc compound solution (zinc lactate with a mass fraction of 15%) was added for further adsorption at a bath ratio of 1:30 for another 60 minutes. After adsorption, dehydration continued until the fibers had a moisture content of 50%. The fibers were then heated to 60°C and reacted for 150 minutes to allow the licorice extract ammonium salt and zinc compound to react fully, generating zinc glycyrrhizinate. Finally, the fibers were washed and dehydrated again to a moisture content of 50%.

[0074] 5. Finishing of fiber preparation The fibers prepared in step 4 are oiled. The oiling agent GA and MGR-H are mixed at a mass ratio of 1:2 to form an oiling emulsion with a concentration of 8.0 g / L. Acetic acid is added to adjust the pH value to 6.9. Then, the fibers prepared in step 4 are added to the above oiling emulsion at a bath ratio of 1:25. The temperature is 70℃ and the treatment time is 2 min to make the fibers weakly acidic. High-pressure rolling is used to achieve a moisture content of 55%. Wet opening is performed, followed by vacuum drying at a drying temperature of 60℃ to achieve a fiber moisture content of 6.5%. Fine opening is then performed to obtain modified natural fibers with soothing and desensitizing functions.

[0075] The modified natural fiber with soothing function prepared in Example 4 exhibits good anti-allergic and antibacterial properties, with an inhibition rate of 93.2% against Escherichia coli, 94.9% against Staphylococcus aureus, and 93.8% against Candida albicans; a mite repellency rate of 93.5%; a mildew resistance rating of 0; and a pH value of 6.8, which matches the slightly acidic nature of human skin, providing good health benefits. After 20 washes, the inhibition rate against Escherichia coli reached 92.3%, against Staphylococcus aureus 93.8%, and against Candida albicans 92.6%; the mite repellency rate was 91.9%; the mildew resistance rating was 0; and the pH value was 7.0.

[0076] Comparative Example 1 Compared with Example 3, this comparative example does not perform air plasma etching, but the rest of the process is exactly the same.

[0077] The modified natural fiber prepared in this comparative example showed an inhibition rate of 71.5% against Escherichia coli, 72.1% against Staphylococcus aureus, and 72.2% against Candida albicans; a mite repellency rate of 65.6%; a mildew resistance level of 2; and a pH value of 6.9. After 20 washes, the inhibition rate against Escherichia coli reached 69.5%, against Staphylococcus aureus 70.3%, and against Candida albicans 70.5%; the mite repellency rate was 63.2%; the mildew resistance level was 2; and the pH value was 7.0.

[0078] As can be seen from Comparative Example 1, the absence of plasma etching reduces the adsorption of functional additives, ultimately affecting the antibacterial, anti-mite, and anti-mildew properties of the modified natural fiber, resulting in a significant reduction in functionality.

[0079] Comparative Example 2 Compared with Example 3, this comparative example does not undergo β-cyclodextrin grafting modification, that is, step 4 is removed, and step 5 directly utilizes the fiber treated in step 3, while the rest of the process is exactly the same.

[0080] The modified natural fiber prepared in this comparative example showed an inhibition rate of 72.2% against Escherichia coli, 73.1% against Staphylococcus aureus, and 73.6% against Candida albicans; a mite repellency rate of 68.7%; a mildew resistance level of 2; and a pH value of 7.0. After 20 washes, the inhibition rate against Escherichia coli reached 67.6%, against Staphylococcus aureus 65.8%, and against Candida albicans 64.9%; the mite repellency rate was 59.6%; the mildew resistance level was 2; and the pH value was 7.0.

[0081] As can be seen from Comparative Example 2, the lack of β-cyclodextrin grafting modification reduces the adsorption of functional additives, ultimately affecting the antibacterial, anti-mite, and anti-mildew properties of the modified natural fiber, resulting in a significant decrease in functionality. Furthermore, the lack of β-cyclodextrin grafting modification also leads to poorer wash resistance.

[0082] Comparative Example 3 Compared with Example 3, this comparative example does not involve preparing the licorice extract ammonium salt solution. Instead, licorice extract is used directly, dissolved in water with a mass fraction of 20%. The prepared β-cyclodextrin-grafted modified natural fiber is added to the licorice extract solution for full adsorption. The rest of the process is exactly the same.

[0083] The modified natural fiber prepared in this comparative example exhibited an inhibition rate of 80.3% against Escherichia coli, 82.2% against Staphylococcus aureus, and 81.6% against Candida albicans; a mite repellency rate of 81.2%; a mildew resistance grade of 1; and a pH value of 6.9. After 20 washes, the inhibition rate against Escherichia coli remained at 78.1%, against Staphylococcus aureus at 81.2%, and against Candida albicans at 79.9%; the mite repellency rate was 78.5%; the mildew resistance grade was 1; and the pH value was 6.9.

[0084] As can be seen from Comparative Example 3, the absence of preparation of licorice extract ammonium salt solution reduces the stability of functional additives, ultimately affecting the antibacterial, anti-mite, and anti-mildew properties of modified natural fibers, resulting in a significant reduction in functionality.

[0085] Comparative Example 4 Compared with Example 4, this comparative example first modifies the natural fiber with licorice extract ammonium salt solution, and then modifies the fiber with β-cyclodextrin grafting. The rest of the process is exactly the same.

[0086] Specific process: Steps 1 and 5 are the same as in Example 4.

[0087] 2. Prepare an ammonium salt solution of licorice extract and utilize natural fibers for adsorption. Licorice extract was dissolved in deionized water at 90°C, with a mass fraction of 20%. After dissolution, activated carbon was added at a mass ratio of 6 times that of the licorice extract in the solution. The mixture was kept at this temperature for 60 minutes to decolorize. After filtration, a filtrate containing licorice extract was obtained. Ammonia was then added to the filtrate, resulting in the formation of a white precipitate. Ammonia was continued to be added until no more precipitate was formed. The precipitate was collected after filtration and dried under vacuum at 60°C to obtain the ammonium salt of licorice extract.

[0088] The ammonium salt of the licorice extract prepared above was dissolved in an ethanol solution with a mass fraction of 95% at 40°C, wherein the mass fraction of the ammonium salt of the licorice extract was 20%. The fiber prepared in step 1 was added to the ammonium salt solution of the licorice extract prepared above at a bath ratio of 1:30 for full adsorption for 60 minutes. After full adsorption, dehydration was carried out, and the water content after dehydration was 50%.

[0089] 3. β-Cyclodextrin grafting modification of natural fibers adsorbing licorice extract ammonium salt solution β-Cyclodextrin was added to an 18% NaOH solution at 50°C and stirred at 400 rpm until completely dissolved, resulting in a β-cyclodextrin mass fraction of 10%. Natural fibers modified with licorice extract ammonium salt solution were then added for finishing, with a bath ratio of 1:30. Epichlorohydrin was then slowly added at a mass ratio of 5:1 to β-cyclodextrin, and the reaction time was 180 min. After the reaction, dehydration was performed, resulting in a moisture content of 50%. The fibers were then subjected to wet opening, drying, and fine opening to obtain β-cyclodextrin-grafted modified licorice extract ammonium salt solution-modified natural fibers for later use.

[0090] 4. Subsequent reactions of natural fibers modified by β-cyclodextrin grafting to adsorb licorice extract ammonium salt solution. Natural fibers grafted with β-cyclodextrin to adsorb licorice extract ammonium salt solution were added to a zinc compound solution for adsorption at a bath ratio of 1:30 for 60 minutes. The zinc compound solution was zinc lactate with a mass fraction of 15%. After adsorption, dehydration was carried out until the fiber had a moisture content of 50%. The fiber was then heated to 60°C and reacted for 150 minutes to allow the licorice extract ammonium salt and zinc compound to react fully, generating zinc glycyrrhizinate. The fiber was then washed and dehydrated again until the moisture content was 50%.

[0091] The modified natural fiber prepared in this comparative example showed an inhibition rate of 83.2% against Escherichia coli, 84.1% against Staphylococcus aureus, and 83.1% against Candida albicans; a mite repellency rate of 82.9%; a mildew resistance grade of 1; and a pH value of 6.9. After 20 washes, the inhibition rate against Escherichia coli was 68.5%, against Staphylococcus aureus was 69.2%, and against Candida albicans was 67.9%; the mite repellency rate was 65.1%; the mildew resistance grade was 2; and the pH value was 7.0.

[0092] As can be seen from Comparative Example 4, firstly modifying the natural fiber with licorice extract ammonium salt solution, and then using β-cyclodextrin graft modification of the above fiber, reduces the stability of the functional additives, ultimately affecting the antibacterial, anti-mite, and anti-mildew functions of the modified natural fiber, significantly reducing its functionality, and also reducing its washability.

Claims

1. A method for preparing modified natural fibers with soothing and desensitizing functions, characterized in that, Includes the following steps: (1) Pre-treatment of natural fibers: First wash with water and then wash with ethanol. After drying, use air plasma to etch for later use. (2) Grafting modification: β-cyclodextrin is added to NaOH solution and mixed. The natural fiber treated in step (1) is added to the above solution and epichlorohydrin is added. After the reaction is completed, dehydration, wet opening, drying and fine opening are performed to obtain grafted modified natural fiber for later use. (3) Preparation of licorice extract ammonium salt solution: Dissolve licorice extract in water, add activated carbon for decolorization, filter, add ammonia water to the filtrate until no more precipitate is formed, collect the precipitate, dry it to obtain ammonium salt of licorice extract, dissolve it in ethanol solution to obtain licorice extract ammonium salt solution with a mass fraction of 15%~20%, for later use; (4) Functional modification: The grafted modified natural fiber obtained in step (2) is added to the licorice extract ammonium salt solution in step (3). After absorption, it is dehydrated and then zinc compound solution is added to continue absorption. After adsorption, the temperature is raised to 30~60℃ and the reaction time is 90~150min. After washing and dehydration, the functional modified natural fiber is obtained and set aside. (5) Finishing: The functionally modified natural fiber from step (4) is oiled, pressed, wet-opened, dried, and finely opened to obtain a modified natural fiber with soothing function.

2. The method for preparing modified natural fibers with soothing function according to claim 1, characterized in that: In step (1), the pre-treatment washing is carried out at a temperature of 80~95℃ and a washing time of 30~40min; the natural fibers are first washed with water and then washed with ethanol, and the moisture content after drying is 50%~65%.

3. The method for preparing modified natural fibers with soothing function according to claim 2, characterized in that: In step (1), the output power of air plasma etching is 250~300W, the pressure is 60~80Pa, and the processing time is 3~8min.

4. The method for preparing modified natural fibers with soothing function according to any one of claims 1-3, characterized in that: In step (2), the grafting modification involves adding β-cyclodextrin to a NaOH solution with a temperature of 45~50℃ and a mass fraction of 18%~22% and mixing it. The natural fiber treated in step (1) is then added to the above solution, with a bath ratio of 1:15~1:

30.

5. The method for preparing modified natural fibers with soothing function according to claim 4, characterized in that: In step (2), the mass ratio of grafted modified epichlorohydrin to β-cyclodextrin is 2:1 to 5:

1.

6. The method for preparing modified natural fibers with soothing function according to claim 5, characterized in that: In step (3), during the preparation of the licorice extract ammonium salt solution, the licorice extract is dissolved in water at 80~90℃.

7. The method for preparing modified natural fibers with soothing function according to claim 1, 5, or 6, characterized in that: In step (4), the functionally modified zinc compound is one or more of zinc sulfate, zinc nitrate, zinc chloride, zinc gluconate, zinc citrate, zinc lactate or zinc glycinate, and the mass fraction of the zinc compound solution is 10%~15%.

8. The method for preparing modified natural fibers with soothing function according to claim 7, characterized in that: In step (5), the oiling process involves mixing the oil agent GA and MGR-H at a mass ratio of 1:1~2, adjusting the pH to 6.0~6.9, adding the functionally modified natural fiber from step (4), with a bath ratio of 1:20~25, a temperature of 50~70℃, and a treatment time of 2~5 minutes.

9. The method for preparing modified natural fibers with soothing function according to claim 8, characterized in that: In step (5), pressing is carried out using a high-pressure rolling mill, with a moisture content of 55% to 65%.

10. A modified natural fiber with soothing function prepared by the method of any one of claims 1-9.