Plant extract composite soothing viscose fiber and preparation method thereof

Abstract

This invention belongs to the field of functional viscose fiber technology, specifically relating to a plant extract composite soothing viscose fiber and its preparation method. The viscose fiber is mainly produced by wet spinning a mixture of microcapsules and viscose spinning solution. The microcapsules consist of a core material and a wall material. The core material comprises dipotassium glycyrrhizate, bisabolol, and asiaticoside in a mass ratio of 1:0.5-0.7:0.2-0.4. The wall material comprises modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose in a mass ratio of 1:1.2-1.8:0.08-0.15. The microcapsules used in this invention are well-formed, have uniform particle size, and high encapsulation efficiency. The active ingredients of the viscose fiber modified by these microcapsules are released uniformly, resulting in a long-lasting effect and maintaining stable soothing function throughout the product's lifespan. Spinning stability is improved, fiber performance remains unchanged, and dry and wet strength, moisture absorption, and softness are maintained well. Made entirely from natural plant materials, with no toxic residues, it can be used in high-safety-standard applications such as medical dressings and infant skincare products.

Description

Technical Field

[0001] This invention belongs to the field of functional viscose fiber technology, specifically relating to a plant extract composite soothing viscose fiber and its preparation method. Background Technology

[0002] Viscose fiber is a regenerated cellulose fiber made from natural cellulose (such as wood and cotton linters) through chemical processing. Its essence is to dissolve natural cellulose and then re-spin it into shape, thus combining the comfort of natural fibers with the controllability of chemical fibers.

[0003] Viscose fiber, with its excellent moisture absorption, breathability, and skin-friendly properties, is widely used in facial masks, baby care fabrics, and skincare textiles. However, pure viscose fiber has relatively limited functionality and cannot meet the needs of the skincare industry. Extensive research in the industry has focused on endowing viscose fiber with soothing and repairing effects by loading functional ingredients. The existing related technical approaches and their main limitations are as follows:

[0004] 1. Single Plant Active Soothing Fiber: It only uses single extracts of licorice, gentian, and centella asiatica, which has a single soothing dimension. Long-term use is prone to skin tolerance and repeated redness. It cannot achieve triple repair of anti-inflammation, redness reduction and stratum corneum barrier at the same time.

[0005] II. Surface finishing process: The soothing ingredients only adhere to the surface of the fiber and are quickly removed by washing and friction, resulting in poor long-lasting effects and failing to meet the requirements for multiple uses.

[0006] III. Traditional microcapsule modification process: Traditional microcapsule wall materials have defects: (1) The aqueous solution has high viscosity, which can easily clog the spinneret during spinning and blending; (2) Formaldehyde residue exists during the preparation and use process, which poses a risk of sensitization to infants and children with severe sensitive skin.

[0007] IV. Modification process of ordinary pectin / gum arabic coagulated microcapsules: Without modification and cross-linking treatment, the membrane has low mechanical strength and is easily broken under high-speed shearing and stretching conditions during spinning. The continuous large-scale production function is severely degraded and it cannot be adapted to the continuous spinning production line of filament.

[0008] Existing patented technologies also include research on soothing and repairing effects: For example, CN116687782A discloses a composition for soothing retinol irritation, which combines ceramides with centella asiatica to effectively alleviate retinol irritation, but the chemical auxiliaries are highly irritating and incompatible with spinning solutions, making it unsuitable for fiber preparation. CN121951721A discloses a soothing functional chemical fiber using natural licorice as raw material, which can be spun in both dry and wet conditions and has antibacterial and anti-mite properties, but it is a single component without synergistic effects of redness reduction and repair, and long-term use may lead to skin tolerance. CN117265684B discloses a method for preparing gentian viscose fiber with soothing effects, using gentian combined with dextran to enhance fiber strength and promote cell regeneration, but it has only a single activity, resulting in weak redness reduction and poor repair effects on damaged skin barriers. Summary of the Invention

[0009] To address the multiple shortcomings of existing technologies, such as single formulation, acid clogging of traditional wall materials, insufficient mechanical strength of ordinary pectin microcapsules, formaldehyde residue, easy loss of activity, and poor stability, this invention provides a plant extract composite soothing viscose fiber and its preparation method.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A plant extract composite soothing viscose fiber is mainly produced by wet spinning of microcapsules mixed with viscose spinning solution. The raw materials of the microcapsules include core material and wall material. The core material includes dipotassium glycyrrhizate, bisabolol, and asiaticoside, with a mass ratio of dipotassium glycyrrhizate, bisabolol, and asiaticoside of 1:0.5-0.7:0.2-0.4. The wall material includes modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose, with a mass ratio of modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose of 1:1.2-1.8:0.08-0.15.

[0012] The amount of microcapsules added does not exceed 8% of the solid content of the viscose spinning solution.

[0013] Furthermore, the added mass of the microcapsules is 3%-8% of the solid content of the viscose spinning solution.

[0014] The modified low-methoxyl pectin is prepared by a method comprising the following steps:

[0015] a) Dissolve low-methoxyl pectin in water to prepare a homogeneous aqueous solution of pectin;

[0016] b) Add trisodium citrate to the homogenized aqueous solution of pectin obtained in step a), stir to dissolve, and then heat to 60-70℃ for 2.5-4 hours;

[0017] c) After the reaction is complete, cool the system to 28-32℃, add ethanol dropwise, and stir to precipitate modified pectin flocs;

[0018] d) The obtained flocs are filtered, washed, dried and pulverized to obtain modified low-methoxyl pectin.

[0019] Further, step a) specifically involves: adding low-methoxyl pectin to water and stirring at a constant temperature of 55-65℃ for 2-4 hours to prepare a homogeneous aqueous solution of pectin.

[0020] Furthermore, in step c), after adding ethanol, the mixture is stirred for 0.5-1.5 hours to precipitate modified pectin flocs.

[0021] Furthermore, in step d), the washing is performed 1-3 times with an aqueous ethanol solution; the drying is performed under vacuum at 35-45°C.

[0022] More preferably, in step d), the volume fraction of ethanol in the aqueous ethanol solution is 40%-60%.

[0023] The raw materials for preparing modified low-methoxyl pectin are as follows by weight: 100 parts low-methoxyl pectin, 3-6 parts trisodium citrate, 150-200 parts ethanol, and 300-400 parts water.

[0024] The water in the raw materials used to prepare the modified low-methoxyl pectin is only the water used to dissolve the low-methoxyl pectin, and does not contain the water in the ethanol aqueous solution used for washing; the ethanol in the raw materials is only the ethanol added to precipitate the modified pectin flocs, and does not contain the ethanol in the ethanol aqueous solution used for washing.

[0025] A method for preparing the above-mentioned plant extract composite soothing viscose fiber includes the following steps:

[0026] 1) Preparation of core and wall material solutions: Dissolve dipotassium glycyrrhizate, bisabolol, and asiaticoside in water to prepare a core material solution with a solid content of 5%-10%; dissolve modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose in water to prepare a wall material solution with a solid content of 8%-15%.

[0027] 2) Preparation of microcapsules by cross-linking and coagulation: The core material solution obtained in step 1) is added dropwise to the wall material solution at a mass ratio of 1:3-6. After stirring, citric acid aqueous solution is added dropwise to adjust the pH of the system to 3.8-4.6 to trigger the coagulation reaction. After the reaction continues for 3-5 hours, the resulting mixture is purified and dried to obtain microcapsule powder.

[0028] 3) Preparation of blended spinning solution: Add the microcapsule powder obtained in step 2) to the viscose spinning solution, stir to remove bubbles, and prepare blended spinning solution;

[0029] 4) Wet continuous spinning: The blended spinning solution obtained in step 3) is extruded through a spinneret and coagulated in a strong acid coagulation bath. The resulting fiber is stretched, washed, and post-treated to obtain soothing viscose fiber.

[0030] In this invention, all solid contents are mass contents.

[0031] Further, in step 1), dipotassium glycyrrhizate, bisabolol, and asiaticoside are added to water and stirred at 40-50°C for 2-4 hours to prepare a core material solution.

[0032] Furthermore, in step 1), modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose are added to water and stirred at 25-30℃ for 3-5 hours to prepare a wall material solution. The solution exhibits low viscosity and no agglomeration gel throughout the process.

[0033] Furthermore, in step 2), the stirring speed is 150-200 r / min. The core material solution is slowly dripped into the wall material solution, with low-speed stirring during the dripping process.

[0034] In step 2), the mass concentration of the citric acid aqueous solution is 8%-12%. The citric acid aqueous solution is added to the system dropwise at a uniform rate of 0.3-0.8 mL / min.

[0035] In step 2), encapsulation is completed after 3-5 hours of reaction. CMC simultaneously participates in cross-linking, forming a bilayer reinforced capsule membrane. The resulting microcapsules have a particle size of 0.5-2 μm.

[0036] In step 2), the purification involves centrifuging the mixture at 2500-3500 r / min for 5-15 min, and washing the resulting precipitate with water. The drying involves vacuum drying at 40-45℃ and a vacuum degree of -0.07 to -0.09 MPa until the water content of the microcapsules is ≤3%. After drying, a free-flowing microcapsule powder is obtained.

[0037] Furthermore, the water washing is performed 2-5 times with deionized water. The purpose of the water washing is to remove free active substances from the surface.

[0038] Furthermore, in step 3), the total amount of microcapsules added is controlled to be within 8% of the solid content of the viscose spinning solution. Controlling the total amount of microcapsules added ensures the mechanical properties of the fiber.

[0039] Furthermore, in step 4), the viscosity of the blended spinning solution is 30-50 Pa·s, the spinneret orifice diameter is 0.06-0.08 mm, and the spinning speed is 45-70 m / min.

[0040] In step 4), the strong acid coagulation bath contains the following components at the following concentrations: sulfuric acid 110-130 g / L, sodium sulfate 220-250 g / L; the bath temperature is 42-48℃. The residence time of the fibers in the strong acid coagulation bath is 12-25 s.

[0041] The strong acid coagulation bath system is equipped with a 3-10μm polypropylene pleated filter cartridge circulation filtration system with a circulation flow rate of 1-1.5m³. 3 / h. The circulating filtration system traps trace amounts of leaked free active liquid, preventing yellowing and contamination of the bath solution and extending the replacement cycle of the coagulation bath.

[0042] Furthermore, in step 4), the stretching is multi-stage stretching; the washing is hot water pre-washing.

[0043] In step 4), the post-treatment includes soaking and drying. Soaking involves immersing the fibers in water at 35-45℃ for 5-15 minutes; drying involves drying at 60-70℃ for 4-6 hours. The purpose of soaking in pure water is to remove free activity from the fiber surface and inhibit microbial growth.

[0044] The preparation method of the present invention ultimately yields a soothing viscose fiber with a fineness of 1.2-2.0D.

[0045] This invention relates to a plant extract composite soothing viscose fiber, primarily produced by wet spinning of microcapsules mixed with viscose spinning solution. The microcapsules consist of a core material and a wall material. The core material utilizes a synergistic soothing system of three plant extracts—dipotassium glycyrrhizate, bisabolol, and asiaticoside—without chemical soothing additives, simultaneously achieving redness reduction, anti-inflammation, and skin barrier repair, making it suitable for medical aesthetic dressings and maternity / baby intimate apparel. The wall material employs a modified low-methoxyl pectin, gum arabic, and a small amount of CMC (sodium carboxymethyl cellulose) crosslinking system. This crosslinking strengthens the capsule membrane, significantly improving the mechanical strength and acid resistance of the microcapsules, solving problems such as breakage in strong acid baths, high-speed shearing, and spinneret clogging during spinning.

[0046] The method for preparing plant extract composite soothing viscose fiber of the present invention adopts a mild re-coagulation preparation process, encapsulation at room temperature, and a low-viscosity blending solution adapted to existing wet continuous spinning equipment to reduce active leakage pollution in the coagulation bath; microcapsules are blended and spun with viscose stock solution, with active ingredients embedded in the fiber matrix, significantly improving the long-lasting effect; the microcapsule addition threshold is controlled to ensure the soothing effect without damaging the original moisture absorption, softness, and mechanical properties of viscose.

[0047] In the plant extract composite soothing viscose fiber of the present invention, the raw material composition of the microcapsules plays the following role:

[0048] Three plant-based soothing core ingredients: Dipotassium glycyrrhizate: Inhibits the release of histamine and IL-6 inflammatory factors, relieving skin redness and stinging, and improving skin discomfort. Bisabolol: Repairs the stratum corneum, strengthens the skin barrier, reduces external irritation from friction and secretions, and improves skin tolerance. Centella asiatica extract: Acts on damaged skin, accelerates skin repair, and improves dryness, itching, and redness.

[0049] Cross-linked reinforced composite wall material: Modified low-methoxyl pectin: Coagulates with gum arabic to form capsules, resistant to strong acids during spinning, low viscosity and non-clogging of the spinneret. Gum arabic: Combined with modified low-methoxyl pectin to form a flexible capsule membrane, regulating the uniform and slow release of activity and avoiding burst release. CMC cross-linking agent: Constructs a cross-linking network, improves the shear strength of the capsules, and solves the problem of microcapsule breakage in large-scale production.

[0050] Auxiliary agent: Citric acid: Adjusts pH, triggers re-agglomeration and encapsulation, gentle and residue-free.

[0051] In the plant extract composite soothing viscose fiber of this invention, the ternary plant synergistic soothing mechanism of the microcapsule core material is as follows: dipotassium glycyrrhizate inhibits inflammatory mediators, bisabolol soothes sensitive nerves, and centella asiatica glycosides repair the stratum corneum; the three components form a synergistic system, and a single raw material cannot simultaneously achieve a triple repair effect. The microcapsule wall material, CMC cross-linked modified low-methoxyl pectin-gum arabic, undergoes re-aggregation to form a basic capsule membrane under weakly acidic conditions. CMC interspersed between polymer chains forms a cross-linked network, significantly improving the membrane's tensile and shear resistance; the membrane itself is resistant to strong acids and can resist corrosion from viscose coagulation baths; it is stable in a dry state and slowly swells and releases its activity upon contact with skin moisture, avoiding one-time irritation.

[0052] In the preparation method of soothing viscose fiber, the original solution is embedded and the circulation filtration mechanism is used; microcapsules are uniformly dispersed in the spinning solution and embedded inside the fiber after molding; the coagulation bath circulation filtration is matched to intercept trace amounts of leaked activity, reduce the frequency of bath solution replacement, and reduce the cost of consumables for continuous production.

[0053] This invention relates to a plant extract composite soothing viscose fiber, which utilizes specially formulated microcapsules to soothe and modify the viscose fiber. The microcapsule core material is a soothing blend of three plant extracts: a chemical-free ternary plant-based soothing blend system. Dipotassium glycyrrhizate, bisabolol, and asiaticoside synergistically achieve triple repair of redness, inflammation, and the stratum corneum barrier, making it suitable for high-safety-standard fabrics used in maternal and infant products and medical aesthetic applications. The microcapsules strengthen the wall material through cross-linking: abandoning traditional wall materials, a CMC cross-linked modified low-methoxyl pectin-gum arabic composite wall material is used; CMC cross-linking enhances the mechanical strength of the capsule membrane, making it less prone to breakage during high-speed spinning and shearing, suitable for continuous large-scale production lines; the system has low viscosity, preventing spinneret clogging during long-term spinning and reducing downtime losses; it is entirely plant polysaccharide-free, formaldehyde-free, and has lower raw material costs.

[0054] The method for preparing plant extract composite soothing viscose fiber of the present invention employs a complex coagulation process at room temperature and a gentle encapsulation process: it requires no high temperature and high pressure, no harmful cross-linking agents, and has low equipment investment. The spinning process is optimized by limiting the maximum amount of microcapsules added to balance efficacy and fiber mechanics; a coagulation bath circulation filtration system is included to solve the problem of bath liquid contamination in continuous production, improving the feasibility of industrialization. The solution-embedded loading process locks the active ingredients inside the fiber, overcoming the industry pain point of easy surface coating detachment.

[0055] Compared with the prior art, the present invention has the following advantages:

[0056] 1. Soothing effect of microcapsules: The microcapsules are well-formed, with uniform particle size and high encapsulation rate. Under simulated usage conditions, the active ingredients are released at a uniform rate within 48 hours, resulting in a long-lasting effect and maintaining stable soothing function throughout the product's lifespan.

[0057] 2. Improved spinning stability: CMC cross-linking enhances the membrane, resulting in less breakage during high-speed continuous spinning; low-viscosity spinning solution prevents spinneret clogging; coagulation bath circulation filtration reduces replacement frequency, solving the problems of functional degradation and frequent shutdowns in large-scale production.

[0058] 3. The overall performance of the wall material is superior to traditional solutions: Compared with chitosan / sodium alginate: raw material costs are reduced and there is no risk of pore blockage; Compared with melamine resin: there is no risk of formaldehyde sensitization, and the membrane is breathable and releases slowly, making it gentler; Compared with uncrosslinked ordinary pectin microcapsules: shear strength is doubled.

[0059] 4. Safe and environmentally friendly, with a wider range of downstream applications: Made from all-natural plant materials, with no toxic residues, it can be used in high-safety-standard scenarios such as medical dressings and infant personal products.

[0060] 5. No degradation in fiber performance: The upper limit of microcapsule addition is strictly controlled, and the fiber strength, moisture absorption and softness are maintained.

[0061] 6. Controllable industrialization costs: Microcapsule preparation is a room temperature reaction, requiring no modification to the main spinning equipment, only the addition of a small circulating filtration device, resulting in low equipment investment, inexpensive raw materials, and minimal production losses. Detailed Implementation

[0062] The present invention will be further described below with reference to specific embodiments.

[0063] In the specific implementation method, the low-methoxyl pectin used is a commercially available product with a degree of esterification of 35%, analytical grade, and was purchased from Guangdong Yuanfeng Chemical Reagent Co., Ltd.

[0064] Example 1

[0065] The plant extract composite soothing viscose fiber of this embodiment is mainly made by wet spinning after mixing microcapsules with viscose spinning solution. The raw materials of the microcapsules include core material and wall material. The core material includes dipotassium glycyrrhizate, bisabolol, and asiaticoside, with a mass ratio of dipotassium glycyrrhizate, bisabolol, and asiaticoside of 1:0.7:0.4. The wall material includes modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose, with a mass ratio of modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose of 1:1.5:0.1.

[0066] The added mass of the microcapsules is 5% of the solid content of the viscose spinning solution.

[0067] The modified low-methoxyl pectin is prepared by a method comprising the following steps:

[0068] a) Add 100 parts by weight of low-methoxyl pectin to 350 parts by weight of deionized water, stir at 60°C for 3 hours to prepare a homogeneous aqueous solution of pectin.

[0069] b) Add 4.5 parts by weight of trisodium citrate to the homogenized aqueous solution of pectin obtained in step a), stir until completely dissolved, heat the system to 65°C, and maintain the temperature for 3 hours for modification reaction;

[0070] c) After the reaction is complete, the system is cooled to 30°C, and 175 parts by weight of anhydrous ethanol is added dropwise at a uniform rate. The mixture is stirred for 1 hour to precipitate modified pectin flocs.

[0071] d) The obtained flocculent was filtered, washed twice with an ethanol-water solution, vacuum dried at 40°C, pulverized, and sieved to obtain modified low-methoxyl pectin. The volume fraction of ethanol in the ethanol-water solution was 40%.

[0072] The preparation method of plant extract composite soothing viscose fiber in this embodiment includes the following steps:

[0073] 1) Prepare core material and wall material solutions:

[0074] Dipotassium glycyrrhizate, bisabolol, and asiaticoside were mixed in proportion and added to deionized water. The mixture was stirred at 50°C for 2 hours to prepare a core material solution with a solid content of 5%.

[0075] Modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose were added to deionized water in a certain proportion and stirred at 28°C for 4 hours to prepare a wall material solution with a solid content of 15%.

[0076] 2) Preparation of microcapsules by cross-linking and complex coagulation:

[0077] According to the mass ratio of core material to wall material of 1:3, the core material solution obtained in step 1) is slowly dripped into the wall material solution. After stirring at a low speed of 180 r / min, a 10% citric acid aqueous solution is dripped into the system at a uniform rate of 0.5 mL / min. The pH value of the system is adjusted to 3.8 to trigger the re-coagulation reaction. The reaction is continued to be stirred for 4 hours to complete the encapsulation and obtain the mixed solution.

[0078] The purification process involved centrifuging the mixture at 3000 r / min for 10 min, washing the resulting precipitate three times with deionized water to remove free active substances from the surface, and then vacuum drying at 43℃ and -0.08 MPa until the water content of the microcapsules was ≤3%, resulting in free-flowing microcapsule powder. The average particle size of the obtained microcapsules was 1 μm.

[0079] 3) Preparation of blend spinning solution:

[0080] The microcapsule powder obtained in step 2) is dispersed at low speed into the viscose spinning solution, and thoroughly stirred to remove bubbles, thus preparing a blended spinning solution; the added mass of the microcapsules is 5% of the solid content of the viscose spinning solution;

[0081] 4) Wet continuous spinning:

[0082] Step 3) The resulting blended spinning solution is extruded through a spinneret and then coagulated in a strong acid coagulation bath; the viscosity of the blended spinning solution is 40 Pa·s, the spinneret orifice diameter is 0.07 mm, and the spinning speed is 70 m / min.

[0083] The strong acid coagulation bath contains the following components at the following concentrations: sulfuric acid 120 g / L, sodium sulfate 235 g / L; bath temperature 45°C; residence time of fibers in the strong acid coagulation bath is 12 s; the production line is equipped with a 5 μm polypropylene pleated filter cartridge circulation filtration system with a circulation flow rate of 1.2 m³ / h. 3 / h, intercepting trace amounts of leaked free active substances, preventing yellowing and contamination of the bath solution, and extending the replacement cycle of the coagulation bath;

[0084] After multi-stage stretching and hot water pre-washing, the fiber is soaked in 40℃ pure water for 10 minutes and then dried at 65℃ for 5 hours to obtain a soothing viscose fiber with a fineness of 1.5D.

[0085] Example 2

[0086] The plant extract composite soothing viscose fiber of this embodiment is mainly made by wet spinning after mixing microcapsules with viscose spinning solution. The raw materials of the microcapsules include core material and wall material. The core material includes dipotassium glycyrrhizate, bisabolol, and asiaticoside, with a mass ratio of dipotassium glycyrrhizate, bisabolol, and asiaticoside of 1:0.6:0.3. The wall material includes modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose, with a mass ratio of modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose of 1:1.8:0.12.

[0087] The added mass of the microcapsules is 8% of the solid content of the viscose spinning solution.

[0088] The modified low-methoxyl pectin is prepared by a method comprising the following steps:

[0089] a) Add 100 parts by weight of low-methoxyl pectin to 400 parts by weight of deionized water, stir at 55°C for 4 hours to prepare a homogeneous aqueous solution of pectin.

[0090] b) Add 6 parts by weight of trisodium citrate to the homogenized aqueous solution of pectin obtained in step a), stir until completely dissolved, heat the system to 60°C, and maintain the temperature for 4 hours for modification reaction.

[0091] c) After the reaction is complete, the system is cooled to 28°C, and 200 parts by weight of anhydrous ethanol is added dropwise at a uniform rate. The mixture is stirred for 1.5 h to precipitate modified pectin flocs.

[0092] d) The obtained flocculent was filtered, washed once with an ethanol-water solution, dried under vacuum at 45°C, pulverized, and sieved to obtain modified low-methoxyl pectin. The volume fraction of ethanol in the ethanol-water solution was 50%.

[0093] The preparation method of plant extract composite soothing viscose fiber in this embodiment includes the following steps:

[0094] 1) Prepare core material and wall material solutions:

[0095] Dipotassium glycyrrhizate, bisabolol, and asiaticoside were mixed in proportion and added to deionized water. The mixture was stirred at 45°C for 3 hours to prepare a core material solution with a solid content of 8%.

[0096] Modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose were added to deionized water in a certain proportion and stirred at 25°C for 5 hours to prepare a wall material solution with a solid content of 11%.

[0097] 2) Preparation of microcapsules by cross-linking and complex coagulation:

[0098] According to the mass ratio of core material to wall material of 1:4.5, the core material solution obtained in step 1) is slowly dripped into the wall material solution. After stirring at a low speed of 150 r / min, an 8% citric acid aqueous solution is dripped into the system at a uniform rate of 0.8 mL / min. The pH value of the system is adjusted to 4.2 to trigger the re-coagulation reaction. The reaction is continued to be stirred for 3 hours to complete the encapsulation and obtain the mixed solution.

[0099] The purification process involved centrifuging the mixture at 2500 r / min for 15 min, washing the resulting precipitate twice with deionized water to remove free active substances from the surface, and then vacuum drying at 40℃ and -0.09 MPa until the water content of the microcapsules was ≤3%, resulting in free-flowing microcapsule powder. The average particle size of the obtained microcapsules was 1.5 μm.

[0100] 3) Preparation of blend spinning solution:

[0101] The microcapsule powder obtained in step 2) is dispersed at low speed into the viscose spinning solution, and thoroughly stirred to remove bubbles, thus preparing a blended spinning solution; the added mass of the microcapsules is 8% of the solid content of the viscose spinning solution;

[0102] 4) Wet continuous spinning:

[0103] Step 3) The resulting blended spinning solution is extruded through a spinneret and then coagulated in a strong acid coagulation bath; the viscosity of the blended spinning solution is 50 Pa·s, the spinneret orifice diameter is 0.07 mm, and the spinning speed is 60 m / min.

[0104] The strong acid coagulation bath contains the following components at the following concentrations: sulfuric acid 110 g / L, sodium sulfate 250 g / L; bath temperature 42℃; residence time of fibers in the strong acid coagulation bath is 18 s; the production line is equipped with a 3 μm polypropylene pleated filter cartridge circulation filtration system with a circulation flow rate of 1.0 m³ / h. 3 / h, intercepting trace amounts of leaked free active substances, preventing yellowing and contamination of the bath solution, and extending the replacement cycle of the coagulation bath;

[0105] After multi-stage stretching and hot water pre-washing, the fiber is soaked in pure water at 35℃ for 15 minutes and then dried at 60℃ for 6 hours to obtain a soothing viscose fiber with a fineness of 1.5D.

[0106] Example 3

[0107] The plant extract composite soothing viscose fiber of this embodiment is mainly made by wet spinning after mixing microcapsules with viscose spinning solution. The raw materials of the microcapsules include core material and wall material. The core material includes dipotassium glycyrrhizate, bisabolol, and asiaticoside, with a mass ratio of dipotassium glycyrrhizate, bisabolol, and asiaticoside of 1:0.5:0.2. The wall material includes modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose, with a mass ratio of modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose of 1:1.2:0.08.

[0108] The added mass of the microcapsules is 3% of the solid content of the viscose spinning solution.

[0109] The modified low-methoxyl pectin is prepared by a method comprising the following steps:

[0110] a) Add 100 parts by weight of low-methoxyl pectin to 300 parts by weight of deionized water, stir at 65°C for 2 hours to prepare a homogeneous aqueous solution of pectin.

[0111] b) Add 3 parts by weight of trisodium citrate to the homogenized aqueous solution of pectin obtained in step a), stir until completely dissolved, heat the system to 70°C, and maintain the temperature for 2.5 h for modification reaction;

[0112] c) After the reaction is complete, the system is cooled to 32°C, and 150 parts by weight of anhydrous ethanol is added dropwise at a uniform rate. The mixture is stirred for 0.5 h to precipitate modified pectin flocs.

[0113] d) The obtained flocculent was filtered, washed three times with an ethanol-water solution, vacuum dried at 35°C, pulverized, and sieved to obtain modified low-methoxyl pectin. The volume fraction of ethanol in the ethanol-water solution was 60%.

[0114] The preparation method of plant extract composite soothing viscose fiber in this embodiment includes the following steps:

[0115] 1) Prepare core material and wall material solutions:

[0116] Dipotassium glycyrrhizate, bisabolol, and asiaticoside were mixed in proportion and added to deionized water. The mixture was stirred at 40°C for 4 hours to prepare a core material solution with a solid content of 10%.

[0117] Modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose were added to deionized water in a certain proportion and stirred at 30°C for 3 hours to prepare a wall material solution with a solid content of 15%.

[0118] 2) Preparation of microcapsules by cross-linking and complex coagulation:

[0119] According to the mass ratio of core material to wall material of 1:6, the core material solution obtained in step 1) is slowly dripped into the wall material solution. After stirring at a low speed of 200 r / min, a 12% citric acid aqueous solution is dripped into the system at a uniform rate of 0.3 mL / min. The pH value of the system is adjusted to 4.6 to trigger the re-coagulation reaction. The reaction is continued to be stirred for 5 hours to complete the encapsulation and obtain the mixed solution.

[0120] The purification process involved centrifuging the mixture at 3500 r / min for 5 min, washing the resulting precipitate five times with deionized water to remove free active substances from the surface, and then vacuum drying at 45℃ and -0.07 MPa until the water content of the microcapsules was ≤3%, resulting in free-flowing microcapsule powder. The average particle size of the obtained microcapsules was 0.8 μm.

[0121] 3) Preparation of blend spinning solution:

[0122] The microcapsule powder obtained in step 2) is dispersed at low speed into the viscose spinning solution, and thoroughly stirred to remove bubbles, thus preparing a blended spinning solution; the added mass of the microcapsules is 3% of the solid content of the viscose spinning solution;

[0123] 4) Wet continuous spinning:

[0124] Step 3) The resulting blended spinning solution is extruded through a spinneret and then coagulated in a strong acid coagulation bath; the viscosity of the blended spinning solution is 30 Pa·s, the spinneret orifice diameter is 0.07 mm, and the spinning speed is 45 m / min.

[0125] The strong acid coagulation bath contains the following components at the following concentrations: sulfuric acid 130 g / L, sodium sulfate 220 g / L; bath temperature 48℃; the residence time of the fibers in the strong acid coagulation bath is 25 s; the production line is equipped with a 10 μm polypropylene pleated filter cartridge circulation filtration system with a circulation flow rate of 1.5 m³ / h. 3 / h, intercepting trace amounts of leaked free active substances, preventing yellowing and contamination of the bath solution, and extending the replacement cycle of the coagulation bath;

[0126] After multi-stage stretching and hot water pre-washing, the fiber is soaked in pure water at 45℃ for 5 minutes and then dried at 70℃ for 4 hours to obtain a soothing viscose fiber with a fineness of 1.5D.

[0127] Comparative Example 1

[0128] The viscose fiber used in this comparative example is a CMC-free crosslinked ordinary pectin microcapsule. The difference from Example 1 is that ordinary pectin is used instead of modified low-methoxyl pectin, and no CMC is added as a crosslinking agent; otherwise, it is the same as Example 1.

[0129] Comparative Example 2

[0130] The viscose fiber used in this comparative example employs a chitosan / sodium alginate wall material. The difference from Example 1 is that the wall material of the microcapsules is replaced with a chitosan / sodium alginate wall material; otherwise, it is the same as in Example 1.

[0131] Comparative Example 3

[0132] In this comparative example, the viscose fiber had the microcapsule addition mass increased to 12% of the solid content of the viscose spinning solution, with the rest being the same as in Example 1.

[0133] Experimental Example

[0134] This experimental example tests the performance of viscose fibers from the embodiment and comparative examples. The experiments include:

[0135] 1. Histamine inhibition rate:

[0136] (1) Experimental cells and models:

[0137] Rabbit skin keratinocytes / mast cells were used to establish an in vitro skin inflammation cell model.

[0138] (2) Experimental procedure:

[0139] ①Routine cell culture was performed, and the cells were divided into blank group, model group, control groups, and the sample group of this invention.

[0140] ② Except for the control group, the other groups were treated with stimulants to induce inflammation in cells and release pro-inflammatory factors;

[0141] ③ The fiber extract to be tested was used to intervene in the culture for a specific duration.

[0142] (3) Calculation formula:

[0143] Using the inhibition rate of pro-inflammatory factors (histamine inhibition rate) as an indicator for evaluating soothing function:

[0144] Inhibition rate of pro-inflammatory factors (%) = (factor concentration in model group - factor concentration in sample group) / (factor concentration in model group - factor concentration in blank group) × 100%.

[0145] 2. Microcapsule breakage rate:

[0146] (1) Experimental steps:

[0147] ① Take a microcapsule dispersion of the same concentration, place it in a high-speed homogenizer, set the shearing speed to be the same as that used for spinning, and shear for 5 minutes to simulate the production process;

[0148] ② Take a small amount of diluted suspension and drop it onto a glass slide. Use an optical microscope to randomly select 5 fields of view.

[0149] ③ Count the total number of intact microcapsules and the total number of microcapsules in each field of view;

[0150] ④ Calculate the damage rate by taking the average value of 5 fields of view.

[0151] (2) Calculation formula

[0152] Microcapsule breakage rate (%) = (Average number of broken microcapsules / Total average number of microcapsules in the field of view) × 100%.

[0153] The test results are shown in Table 1.

[0154] Table 1. Physicochemical properties of viscose fibers and microcapsule stability data of the examples and comparative examples.

[0155]

[0156] 3. Experimental Data Analysis

[0157] (1) Comparison of soothing effects: The histamine inhibition rate of the three groups of examples after 48 hours was higher than that of the two groups of traditional wall materials, Comparative Examples 1 and 2. Among them, the core material ratio of Example 2 had the best soothing effect, while the core material addition of Example 3 was the lowest, and the soothing effect was slightly reduced, but the fiber mechanical properties were the best. The addition of microcapsules in Comparative Example 3 exceeded the standard, and the soothing effect was close to that of the examples, but the dry and wet strength of the fiber declined. The test results show that the active ingredients of the viscose fiber obtained by the present invention are released at a uniform rate within 48 hours, with a long duration of action, and the product can maintain a stable soothing function throughout the process.

[0158] (2) Comparison of microcapsule shear stability: The breakage rate of microcapsules in the CMC crosslinking system of Examples 1-3 was 2.8%-4.1%; the breakage rate of the non-CMC crosslinking system in Comparative Example 1 was 32.7%, and the breakage rate of the seaweed / chitosan wall material in Comparative Example 2 was 64.5%. The test results show that the CMC crosslinking network in the microcapsule wall material used in this invention can improve the shear resistance of the capsule membrane.

[0159] (3) Comparison of fiber physical properties: The dry and wet strength, elongation, and water absorption rate of the viscose fibers in Examples 1-3 were all superior to those in Comparative Examples 1-3. Comparative Example 3 showed that when the amount of microcapsules added was increased to 12% of the solid content of the viscose spinning solution, the mechanical properties of the fiber decreased. The test results showed that within the range of microcapsule addition in this invention, the fiber properties did not decrease, and the fiber strength, moisture absorption, and softness remained good.

Claims

1. A plant extract composite soothing viscose fiber, characterized in that, The product is mainly made by wet spinning a mixture of microcapsules and viscose spinning solution. The raw materials of the microcapsules include core material and wall material. The core material includes dipotassium glycyrrhizate, bisabolol, and asiaticoside, with a mass ratio of dipotassium glycyrrhizate, bisabolol, and asiaticoside of 1:0.5-0.7:0.2-0.

4. The wall material includes modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose, with a mass ratio of modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose of 1:1.2-1.8:0.08-0.

15.

2. The plant extract composite soothing viscose fiber according to claim 1, characterized in that, The amount of microcapsules added does not exceed 8% of the solid content of the viscose spinning solution.

3. The plant extract composite soothing viscose fiber according to claim 1, characterized in that, The modified low-methoxyl pectin is prepared by a method comprising the following steps: a) Dissolve low-methoxyl pectin in water to prepare a homogeneous aqueous solution of pectin; b) Add trisodium citrate to the homogenized aqueous solution of pectin obtained in step a), stir to dissolve, and then heat to 60-70℃ for 2.5-4 hours; c) After the reaction is complete, cool the system to 28-32℃, add ethanol dropwise, and stir to precipitate modified pectin flocs; d) The obtained flocs are filtered, washed, dried and pulverized to obtain modified low-methoxyl pectin.

4. The plant extract composite soothing viscose fiber according to claim 3, characterized in that, The raw materials for preparing modified low-methoxyl pectin are as follows by weight: 100 parts low-methoxyl pectin, 3-6 parts trisodium citrate, 150-200 parts ethanol, and 300-400 parts water.

5. A method for preparing plant extract composite soothing viscose fiber as described in any one of claims 1-4, characterized in that, Includes the following steps: 1) Preparation of core and wall material solutions: Dissolve dipotassium glycyrrhizate, bisabolol, and asiaticoside in water to prepare a core material solution with a solid content of 5%-10%; dissolve modified low-methoxyl pectin, gum arabic, and sodium carboxymethyl cellulose in water to prepare a wall material solution with a solid content of 8%-15%. 2) Preparation of microcapsules by cross-linking and coagulation: The core material solution obtained in step 1) is added dropwise to the wall material solution at a mass ratio of 1:3-6. After stirring, citric acid aqueous solution is added dropwise to adjust the pH of the system to 3.8-4.6 to trigger the coagulation reaction. After the reaction continues for 3-5 hours, the resulting mixture is purified and dried to obtain microcapsule powder. 3) Preparation of blended spinning solution: Add the microcapsule powder obtained in step 2) to the viscose spinning solution, stir to remove bubbles, and prepare blended spinning solution; 4) Wet continuous spinning: The blended spinning solution obtained in step 3) is extruded through a spinneret and coagulated in a strong acid coagulation bath. The resulting fiber is stretched, washed, and post-treated to obtain soothing viscose fiber.

6. The method for preparing plant extract composite soothing viscose fiber according to claim 5, characterized in that, In step 2), the mass concentration of the citric acid aqueous solution is 8%-12%.

7. The method for preparing plant extract composite soothing viscose fiber according to claim 5, characterized in that, In step 2), the purification involves centrifuging the mixture at 2500-3500 r / min for 5-15 min and washing the resulting precipitate with water; the drying involves vacuum drying at 40-45℃ and a vacuum degree of -0.07 to -0.09 MPa until the water content of the microcapsules is ≤3%.

8. The method for preparing plant extract composite soothing viscose fiber according to claim 5, characterized in that, In step 4), the strong acid coagulation bath contains the following components at the following concentrations: sulfuric acid 110-130 g / L, sodium sulfate 220-250 g / L; bath temperature 42-48℃.

9. The method for preparing plant extract composite soothing viscose fiber according to claim 5 or 8, characterized in that, The strong acid coagulation bath system is equipped with a 3-10μm polypropylene pleated filter cartridge circulation filtration system with a circulation flow rate of 1-1.5m³. 3 / h.

10. The method for preparing plant extract composite soothing viscose fiber according to claim 5, characterized in that, In step 4), the post-treatment includes soaking and drying; the soaking is to soak the fibers in water at 35-45℃ for 5-15 minutes; the drying is to dry at 60-70℃ for 4-6 hours.

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