Light lyocell cotton denim with low fibrillation and antibacterial and anti-mosquito functions and preparation method of light lyocell cotton denim

Abstract

The invention provides light lyocell cotton denim with low fibrillation and antibacterial and anti-mosquito functions and a preparation method of the light lyocell cotton denim, and relates to the technical field of functional finishing of textiles. The preparation method of the light lyocell cotton denim with low fibrillation and antibacterial and anti-mosquito functions comprises the five steps of fabric pretreatment, finishing liquid preparation, double-section padding, third-order curing and after-finishing. Through the synergistic effect of gradient crosslinking and natural antibacterial and anti-mosquito components, the fabric is endowed with lasting antibacterial and anti-mosquito functions while fibrillation of lyocell fibers is effectively inhibited, the technical problem that in a traditional finishing method, it is difficult to consider both fibrillation and functionality at the same time is solved, and the antibacterial and anti-mosquito effects of the fabric are improved. And the prepared fabric has excellent fibrillating resistance, lasting antibacterial and anti-mosquito effects and good softness and comfort.

Description

Technical Field

[0001] This invention relates to the field of textile functional finishing technology, and in particular to a lightweight Lyocell cotton denim fabric with both low fibrillation and antibacterial and mosquito-repellent functions, and its preparation method. Background Technology

[0002] Lyocell fiber is a new type of regenerated cellulose fiber with excellent moisture absorption and breathability, good drape and silky luster, and is widely used in the field of clothing fabrics.

[0003] However, lyocell fibers are prone to fibrillation under wet conditions, where tiny fibrils form on the fiber surface. This leads to pilling, a rough hand feel, and reduced strength, severely impacting the fabric's performance and appearance. Traditional antifibrillation finishing methods primarily employ resin cross-linking to inhibit fibrillation by increasing the degree of cross-linking. However, high cross-linking levels result in stiff fabrics, reduced moisture absorption, and poor breathability, making it difficult to meet the softness and comfort requirements of lightweight denim.

[0004] Meanwhile, with the increasing demand for functional textiles, antibacterial and mosquito-repellent functions have become an important performance indicator for summer clothing fabrics. Existing antibacterial and mosquito-repellent finishing methods mostly use chemically synthesized agents, which have problems such as poor wash resistance, short effective period, and potential safety hazards.

[0005] Therefore, developing a finishing method that can effectively inhibit fibrillation, impart long-lasting antibacterial and mosquito-repellent functions, and maintain the softness and comfort of fabrics has important theoretical significance and application value. Summary of the Invention

[0006] In view of this, the present invention provides a lightweight lyocell cotton denim fabric with both low fibrillation and antibacterial and mosquito-repellent functions, as well as a method for its preparation. The present invention constructs a micro-pitted structure on the fiber surface through enzymatic treatment, combined with a gradient crosslinking and inclusion-slow-release system of natural active ingredients. This achieves excellent fibrillation effect under low crosslinking conditions, while simultaneously endowing the fabric with long-lasting antibacterial and mosquito-repellent functions, thus achieving a balance between functionality and comfort, and has promising application prospects.

[0007] The first aspect of this invention is to provide a method for preparing lightweight Lyocell cotton denim fabric that combines low fibrillation and antibacterial and mosquito-repellent functions, comprising the following steps: S1. Fabric pretreatment: The Lyocell cotton denim is enzymatically treated to create micro-pits on the fiber surface. After treatment, the enzymes are inactivated and the fabric is washed with water. S2. Preparation of finishing solution: Prepare a gradient functional finishing working solution containing gradient cross-linking components, antibacterial and mosquito-repellent components and synergistic components; S3, Two-stage padding: The finishing working solution is applied to the fabric using a two-stage padding process to form a gradient distribution of functional components; S4, Three-stage curing: The impregnated fabric is pre-dried, medium-temperature baked and zoned high-temperature cured in sequence to construct a gradient cross-linking network; S5. Finishing: The cured fabric is washed, dried and functionally protected to obtain lightweight Lyocell cotton denim with low fibrillation and antibacterial and mosquito-repellent functions.

[0008] Preferably, the enzyme treatment conditions in step S1 are as follows: neutral cellulase with an enzyme activity of 2000-4000 U / g, a dosage of 0.3-0.8% wf, a liquor ratio of 1:(12-16), a temperature of 45-52℃, a pH of 6.0-7.0, and a treatment time of 20-35 min. The depth of the micro-pits is 0.3-0.8 µm, and the surface roughness Ra value of the fabric after treatment is 1.5-2.5 µm, ensuring that the microstructure is maintained after subsequent finishing, providing anchoring points for functional components and increasing the specific surface area.

[0009] Preferably, in step S2, the gradient functional finishing working solution comprises, by weight, 33-64 parts of gradient crosslinking component, 30-50 parts of antibacterial and mosquito-repellent component, 12-24 parts of synergistic component, and water to a total of 1000 parts. The gradient crosslinking component includes 10-18 parts of citric acid, 3-8 parts of maleic acid, 8-14 parts of nano-modified chitosan, 4-9 parts of crosslinking catalyst, and 8-15 parts of nano-plant wax emulsion. The antibacterial and mosquito-repellent components include 18-30 parts of bridged bicyclodextrin inclusion complex, 7-12 parts of plant tannin-polyglutamic acid composite fixative, and 5-8 parts of cross-linked modified starch nanocarrier. The synergistic effect-enhancing components include 3-6 parts of a metal ion chelating agent, 1.5-3 parts of an antioxidant, 6-12 parts of a moisturizing stabilizer, and 2-5 parts of a penetration enhancer.

[0010] Preferably, the degree of deacetylation of the nano-modified chitosan is 75-85%, the particle size is 150-350 nm, the modification method is carboxymethylation modification, and the degree of substitution is 0.4-0.8, so as to improve water solubility and binding force with fibers; the crosslinking catalyst is a mixture of sodium hypophosphite and magnesium sulfate in a mass ratio of (3-5):1, with sodium hypophosphite acting as the main catalyst to catalyze the esterification reaction, and magnesium sulfate acting as a synergistic catalyst to improve crosslinking efficiency and improve fabric whiteness; the nano-plant wax emulsion has a particle size of 80-200 nm and a solid content of 25-35%, forming a hydrophobic protective layer on the fabric surface.

[0011] Preferably, the bridged bicyclodextrin inclusion complex consists of an inner cavity containing a mosquito-repellent component and an outer cavity adsorbed with an antibacterial component; the inner cavity diameter of the bridged bicyclodextrin is 6.5-7.8 Å, the outer cavity is carboxylated with a degree of carboxylation of 15-25%, and the bridging group is adipic acid or succinic acid, forming a stable dimer structure; the mosquito-repellent component includes 35-45% Artemisia argyi essential oil, whose main component is eucalyptol, and 25-35% Neem seed oil, whose main component is... The product contains 25-35% azadirachtin and 25-35% citronellol essential oil, the main component of which is citronellal. These three components work synergistically to provide a broad-spectrum mosquito repellent effect. The antibacterial components include 20-30% rosemary extract, with a rosmarinic acid content of ≥15%, 15-25% thyme essential oil, with a thymol content of ≥40%, 20-30% cinnamon extract, with a cinnamaldehyde content of ≥50%, and 25-35% nano-silver-chitosan complex, with a silver content of 200-500 ppm. These four components work synergistically to provide highly effective antibacterial properties.

[0012] Preferably, the plant tannin-polyglutamic acid composite fixative is an electrostatic complex formed by the reaction of plant tannin and polyglutamic acid under pH 5.0-5.5 conditions. The plant tannin is a hydrolyzed tannin with a gallic acid content ≥60%, and the polyglutamic acid has a molecular weight of 50,000-100,000. The mass ratio of the two is (2-3):1. Under weakly acidic conditions of pH 5.0-5.5, the phenolic hydroxyl groups of the plant tannin are deprotonated and become negatively charged, while the carboxyl and amino groups of the polyglutamic acid are in a zwitterionic state. A stable complex is formed through electrostatic interaction and hydrogen bonding. This complex can form multi-point hydrogen bond with cellulose fibers and cross-link with functional components, significantly improving the wash resistance of the finishing agent.

[0013] Preferably, the cross-linked modified starch nanocarrier is modified by acetic acid esterification with a degree of substitution of 0.5-1.2, which improves the hydrophobicity of starch and its compatibility with active ingredients. At the same time, sodium trimetaphosphate is used as a cross-linking agent at an amount of 3-6% of the starch mass to form a cross-linked network between starch molecules, thereby enhancing the stability and sustained-release performance of the carrier. The cross-linked modified starch nanocarrier has a particle size of 100-300 nm and is uniformly dispersed inside the fiber. Through physical encapsulation and chemical adsorption, it loads antibacterial and mosquito-repellent active ingredients to achieve a long-lasting sustained-release function.

[0014] Preferably, the metal ion chelating agent is phytic acid, used to chelate metal ions such as iron and copper in the finishing solution, preventing the oxidative degradation of catalytic active ingredients; the antioxidant is tocopherol, protecting essential oil-based active ingredients from oxidative inactivation; the moisturizing stabilizer is glycerin and / or sorbitol, which can maintain the stability of the finishing solution and improve the softness and moisturizing properties of the fabric; the penetration promoter is polyoxyethylene fatty alcohol ether, which reduces the surface tension of the finishing solution and promotes the penetration of functional components into the fiber; the pH value of the finishing solution is adjusted to 4.8-5.5 using citric acid / sodium citrate buffer, with a buffer capacity ≥0.05ml / L. This pH range can maintain the stability of the electrostatic complex and ensure the cross-linking activity of the citric acid-maleic acid system, achieving synergy between the two functional mechanisms.

[0015] Preferably, in step S2, the preparation method of the gradient functional finishing working solution includes the following steps: (1) Pre-inclusion reaction: the mosquito repellent component is mixed with the bridged bicyclodextrin, and stirred at 45-55℃ with a stirring speed of 200-300 rpm for 1.5-2.5 h to form an inner cavity inclusion complex. The hydrophobicity of the inner cavity of the cyclodextrin and the hydrophobicity of the essential oil components are used to achieve effective inclusion and improve the stability of volatile components; (2) Antibacterial component adsorption: the antibacterial component is added to the product of step (1), the temperature is controlled at 40-50℃, the residual temperature of the previous step is used and the temperature is slightly reduced, the stirring speed is 150-250 rpm, and the reaction time is 1-2 h. h, by using the carboxylation modification of the bridging bicyclodextrin cavity to adsorb antibacterial components, a bifunctional inclusion complex with both mosquito repellent and antibacterial functions was prepared; (3) Fixative compound: In a separate system, plant tannins and polyglutamic acid were mixed, the pH value was controlled at 5.0-5.5, the temperature was 30-40℃, the stirring speed was 100-200 rpm, and the reaction time was 40-60 minutes. min, forming an electrostatic complex. This step can be carried out simultaneously with (4) to improve efficiency; (4) Construction of the main system: mix citric acid, maleic acid, crosslinking catalyst and nano-modified chitosan, at a temperature of 30-40℃, stir until completely dissolved to form the main system of the crosslinking reaction; (5) Maturation: add the bifunctional inclusion complex of step (2) and the electrostatic complex of step three to the main system of step (4), and add crosslinked modified starch nanocarrier, nano plant wax emulsion and synergistic component in sequence. Adjust the pH to 4.8-5.5 with citric acid / sodium citrate buffer, let the temperature drop naturally to 25-35℃, and let it stand for 2-4 h to allow the components to fully interact and form a stable and uniform finishing working solution. The final pH is 4.8-5.5 and the viscosity is 50-150 mPa·s.

[0016] Preferably, in step S3, the two-stage padding process includes: a first stage of high-temperature adsorption-penetration, with the finishing liquid temperature at 55-65℃, padding time at 12-18 min, and a roll-off rate of 70-80%. Under higher temperature and higher roll-off rate, the finishing agent is ensured to fully impregnate the fabric, and macromolecular components and small molecule crosslinking agents enter the fiber simultaneously; a second stage of temperature-controlled directional distribution, with the finishing liquid temperature appropriately reduced to 45-55℃, padding time at 8-15 min, and roll-off rate reduced to 55-70% to remove excess liquid. The lower temperature reduces the diffusion rate of macromolecular components, which preferentially deposit on the surface, while the small molecule crosslinking agent still maintains sufficient kinetic energy to continue to diffuse inward, forming a gradient distribution of surface enrichment and inward penetration.

[0017] Preferably, the three-stage curing process in step S4 includes: a pre-drying stage, with a temperature of 65-75℃ and a time of 4-7 minutes, to slowly remove moisture and control the fabric moisture regain to 35-45%, preventing rapid drying from causing surface migration and uneven distribution of the finishing agent; a medium-temperature baking stage, with a temperature of 95-108℃ and a time of 5-9 minutes, at which temperature the cyclodextrin inclusion complex crystallizes and solidifies, and hydrogen bond networks are formed between components such as cellulose, chitosan, and tannins, initiating the citric acid-maleic acid crosslinking reaction; and a high-temperature curing stage, using zoned progressive temperature control, with the first zone at 135-142℃, the second zone at 142-150℃, and the third zone at 148-155℃, for a total time of 4-7 minutes, gradually increasing the temperature to ensure that the citric acid-cellulose esterification reaction is fully completed.

[0018] Preferably, the finishing process in step S5 includes two parts: washing and functional protection finishing. In the washing stage, the temperature is 40-50℃, the time is 10-15 min, and the liquor ratio is 1:(15-20) to remove unfixed finishing agents and reaction byproducts, ensuring the cleanliness and safety of the fabric. In the functional protection finishing stage, the fabric is impregnated with hyperbranched polyester softener and short-chain fluorocarbon water repellent. The hyperbranched polyester softener dosage is 20-40 g / L, giving the fabric a soft hand feel and good drape. The short-chain fluorocarbon water repellent uses C6 type environmentally friendly product, with a dosage of 15-30 g / L, to form a water- and oil-repellent protective layer on the fabric surface. The impregnation time is 3-5 min, and the pick-up rate is 65-75%. Then, it is dried and set at 120-135℃ for 3-5 min, so that the softener and water repellent form a stable functional layer on the fabric surface.

[0019] A second aspect of the present invention is to provide a lyocell cotton denim fabric prepared by the above method, wherein the lyocell cotton denim fabric has a three-dimensional gradient network structure from the outside to the inside, including a surface protective layer, an internal cross-linking layer and a sustained-release regulating layer penetrating the fibers; The surface protective layer is located within a depth of 0-2 µm on the fiber surface. It is composed of an enriched chitosan-plant tannin composite membrane, nano-plant wax, and cyclodextrin inclusion complex. It is the main carrier layer of antibacterial and mosquito-repellent active ingredients and a water- and dirt-repellent protective layer. It increases the specific surface area through micro-pits, enhances the durability of the function, and presents a continuous and dense membrane structure. It fills and retains some micro-pits with a pit depth of 0.3-0.8 µm. The internal cross-linking layer is located in the fiber depth range of 2-10 µm, has a citric acid-maleic acid synergistic cross-linking network, and the degree of cross-linking is 12-25%. It provides structural stability to inhibit fibrillation, locks in functional components, maintains fabric dimensional stability, and presents a three-dimensional network cross-linking structure. The sustained-release regulating layer that runs through the fiber consists of cross-linked modified starch nanocarriers and cyclodextrin inclusion complexes dispersed inside the fiber. It exhibits a concentration gradient distribution from the fiber surface to the core. The nanoparticles have a particle size of 100-350 nm, are uniformly dispersed, and are anchored to the fiber molecular chain through hydrogen bonds and van der Waals forces. This allows for the sustained release of antibacterial and mosquito-repellent active ingredients, providing long-lasting functional retention and regulating the release rate of the functional ingredients.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows: Traditional methods that increase crosslinking degree can enhance antigen fibrillation performance but reduce softness and moisture absorption. This invention, however, employs a gradient crosslinking process. Through a gradient distribution of high surface crosslinking and moderate internal crosslinking, it significantly reduces the overall crosslinking degree while maintaining antigen fibrillation effect, thus improving the fabric's softness and moisture absorption.

[0021] This invention achieves synergistic and sustained release of antibacterial and mosquito-repellent functions through a bicyclic dextrin inclusion complex-based dual-function sustained-release system.

[0022] This invention employs a mild enzymatic treatment to construct a micro-pit structure on the fiber surface, increasing the specific surface area and roughness, thereby significantly improving the fixation rate and functional durability of the finishing agent.

[0023] This invention uses a plant-derived tannin-polyglutamic acid electrostatic composite fixative, which significantly improves the wash fastness of natural active ingredients through multi-point hydrogen bonding and cross-linking, thus solving the problem of easy loss of plant-derived antibacterial and mosquito repellent agents.

[0024] This invention uses natural plant-derived antibacterial and mosquito-repellent ingredients to replace chemically synthesized reagents, which is highly safe, biocompatible, and has good application prospects. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1This is a flowchart illustrating the preparation process of the lightweight Lyocell cotton denim fabric with low fibrillation and antibacterial and mosquito-repellent functions of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, all experiments were repeated three times. Results are expressed as mean ± standard deviation, and P < 0.05 indicates a significant difference.

[0029] Example 1: A method for preparing a lightweight Lyocell cotton denim fabric with both low fibrillation and antibacterial / mosquito-repellent properties, comprising the following steps: S1. Raw material preparation: Lyocell cotton denim: Lyocell fiber to cotton fiber blend ratio 60:40, fabric weight 220 g / m² 2 ; Neutral cellulase: Enzyme activity 3000 U / g; Citric acid: analytical grade; Maleic acid: analytical grade; Nano-modified chitosan: degree of deacetylation 80%, particle size 250 nm, degree of carboxymethylation substitution 0.6; Sodium hypophosphite: Industrial grade; Magnesium sulfate: Industrial grade; Nano-plant wax emulsion: particle size 150 nm, solid content 30%; Bridged bicyclodextrin: luminal diameter 7.2 Å, degree of carboxylation 20%, bridging group is adipic acid; Artemisia argyi essential oil, neem seed oil, lemongrass essential oil, rosemary extract, thyme essential oil, cinnamon extract; Nano silver-chitosan complex: silver content 350 ppm; Plant tannins: Hydrolyzed tannins with 65% gallic acid content; Polyglutamic acid: molecular weight 80,000; Crosslinked modified starch: esterified with acetate, degree of substitution 0.8, sodium trimetaphosphate crosslinking agent dosage 4.5%; Phytic acid, tocopherol, glycerin, polyoxyethylene fatty alcohol ethers; Hyperbranched polyester softener, C6 type short-chain fluorocarbon water repellent; S2. Fabric pretreatment: Lyocell cotton denim was subjected to enzyme treatment under the following conditions: neutral cellulase dosage 0.5% wf, enzyme activity 3000 U / g, liquor ratio 1:14, temperature 48℃, pH 6.5, and treatment time 28 min. After treatment, the enzyme was inactivated at 95℃ for 10 min, followed by hot water washing and cold water rinsing. The treated fabric surface had micro-pits with a depth of 0.5 µm, a surface roughness Ra value of 2.0 µm, and a pit retention rate of 90%. S3. Preparation of finishing solution: Prepare a gradient functional finishing working solution (total 1000 parts) according to the following formula (parts by weight): Gradient crosslinking components (48 parts): citric acid (14 parts), maleic acid (5 parts), nano-modified chitosan (11 parts), crosslinking catalyst (sodium hypophosphite: magnesium sulfate = 4:1) (6.5 parts), and nano-plant wax emulsion (11.5 parts). 40 parts of antibacterial and mosquito-repellent components: 24 parts of bridged bicyclodextrin inclusion complex (internal mosquito-repellent components: 40% Artemisia argyi essential oil, 30% Neem seed oil, 30% Citronella essential oil; external antibacterial components: 25% Rosemary extract, 20% Thyme essential oil, 25% Cinnamon extract, 30% Nano silver-chitosan complex), 9.5 parts of plant tannin-polyglutamic acid composite fixative (plant tannin: polyglutamic acid = 2.5:1), and 6.5 parts of cross-linked modified starch nanocarrier; Synergistic synergistic components (18 parts): phytic acid (4.5 parts), tocopherol (2.2 parts), glycerol (9 parts), polyoxyethylene fatty alcohol ether (3.5 parts); Add deionized water to a total of 1000 parts; Preparation steps: Pre-inclusion reaction: The mosquito repellent components (artemisia oil, neem seed oil, and lemongrass oil in proportion) were mixed with bridged bicyclodextrin and stirred at 250 rpm for 2 h at 50°C. Adsorption of antibacterial components: Add the antibacterial components, lower the temperature to 45℃, and stir at 200 rpm for 1.5 h; Fixative compound: plant tannins and polyglutamic acid are mixed, pH 5.2, 35℃, and stirred at 150 rpm for 50 min; Main system construction: Citric acid, maleic acid, cross-linking catalyst, and nano-modified chitosan were mixed and stirred at 35°C until completely dissolved; Maturation: Add bifunctional inclusion complex, electrostatic complex, cross-linked modified starch nanocarrier, nano plant wax emulsion, and synergistic component in sequence. Adjust the pH to 5.0 with citric acid / sodium citrate buffer, lower the temperature to 30℃, and let it stand for 3 hours to mature. The final finishing solution has a pH of 5.0 and a viscosity of 100 mPa·s. S4. Two-stage padding: The finishing solution is applied to the fabric using a two-stage padding process; First stage: Finishing solution temperature 60℃, immersion time 15 min, roll-out rate 75%; Second stage: Finishing solution temperature 50℃, immersion time 12 min, roll residue 62%; S5, Three-stage curing: The impregnated fabric is pre-dried, medium-temperature baked and zoned high-temperature cured in sequence; Pre-drying: 70℃, 6 min, fabric moisture regain 40%; Medium temperature baking: 102℃, 7 minutes; High-temperature curing: Zone 1 138℃, Zone 2 146℃, Zone 3 152℃, total time 5.5 min; S6. Finishing: The cured fabric is washed (45℃, 12 min, liquor ratio 1:18), dried and functionally protected (branched polyester softener 30 g / L, C6 type short chain fluorocarbon water repellent 22 g / L, padding for 4 min, pick-up rate 70%), dried and set at 128℃ for 4 min to obtain lightweight Lyocell cotton denim with low fibrillation and antibacterial and mosquito-repellent functions.

[0030] Example 2 Same as Example 1, except that: S2 finishing solution formula adjustment: Gradient crosslinking components (33 parts): citric acid (10 parts), maleic acid (3 parts), nano-modified chitosan (8 parts), crosslinking catalyst (4 parts), and nano-plant wax emulsion (8 parts). Antibacterial and mosquito-repellent components (30 parts): 18 parts of bridged bicyclodextrin inclusion complex, 7 parts of plant tannin-polyglutamic acid composite fixative, and 5 parts of cross-linked modified starch nanocarrier; Synergistic synergistic components (12 parts): phytic acid (3 parts), tocopherol (1.5 parts), glycerin (6 parts), and polyoxyethylene fatty alcohol ether (2 parts).

[0031] Example 3 Same as Example 1, except that: S2 finishing solution formula adjustment: Gradient crosslinking components (64 parts): citric acid (18 parts), maleic acid (8 parts), nano-modified chitosan (14 parts), crosslinking catalyst (9 parts), and nano-plant wax emulsion (15 parts). Antibacterial and mosquito-repellent components (50 parts): 30 parts of bridged bicyclodextrin inclusion complex, 12 parts of plant tannin-polyglutamic acid composite fixative, and 8 parts of cross-linked modified starch nanocarrier; Synergistic synergistic components (24 parts): phytic acid (6 parts), tocopherol (3 parts), glycerin (12 parts), and polyoxyethylene fatty alcohol ether (5 parts).

[0032] Example 4 Same as Example 1, except that: S1 enzyme treatment conditions: enzyme dosage 0.3% wf, enzyme activity 2000 U / g, bath ratio 1:12, temperature 45℃, pH 6.0, treatment time 20 min.

[0033] Example 5 Same as Example 1, except that: S1 enzyme treatment conditions: enzyme dosage 0.8% wf, enzyme activity 4000 U / g, bath ratio 1:16, temperature 52℃, pH 7.0, treatment time 35 min.

[0034] Example 6 Same as Example 1, except that: S3 Two-Stage Dipping Process Adjustment: First Stage: Finishing liquid temperature 55℃, dipping time 12 min, roll yield 70%; Second Stage: Finishing liquid temperature 45℃, dipping time 8 min, roll yield 55%.

[0035] Example 7 Same as Example 1, except that: S3 Two-Stage Dipping Process Adjustment: First Stage: Finishing liquid temperature 65℃, dipping time 18 min, roll yield 80%; Second Stage: Finishing liquid temperature 55℃, dipping time 15 min, roll yield 70%.

[0036] Example 8 Same as Example 1, except that: S4 three-stage curing process adjustment: Pre-baking: 65℃, 4 min, fabric moisture regain 35%; Medium-temperature baking: 95℃, 5 min; High-temperature curing: Zone 1 135℃, Zone 2 142℃, Zone 3 148℃, total time 4 min.

[0037] Example 9 Same as Example 1, except that the S4 three-stage curing process is adjusted: Pre-drying: 75℃, 7 min, fabric moisture regain 45%; medium-temperature baking: 108℃, 9 min; high-temperature curing: zone 1 142℃, zone 2 150℃, zone 3 155℃, total time 7 min.

[0038] Example 10 Same as Example 1, except that: In the S2 preparation steps: pre-inclusion reaction: 45℃, 200 rpm, 1.5 h; antibacterial component adsorption: 40℃, 150 rpm, 1 h; fixative compounding: pH 5.0, 30℃, 100 rpm, 40 min; maturation time: 2 h.

[0039] Example 11 Same as Example 1, except that in the S2 preparation step: pre-inclusion reaction: 55℃, 300 rpm, 2.5 h; antibacterial component adsorption: 50℃, 250 rpm, 2 h; fixative compounding: pH 5.5, 40℃, 200 rpm, 60 min; ripening time: 4 h.

[0040] Comparative Example 1 Same as Example 1, except that: the S1 fabric pretreatment step is omitted, and the untreated Lyocell cotton denim is directly finished.

[0041] Comparative Example 2 Same as Example 1, except that: the S2 finishing solution formula does not contain bridged bicyclodextrin inclusion complex, only conventional cross-linking finishing is used, and the remaining components are adjusted proportionally to maintain a total of 1000 parts.

[0042] Comparative Example 3 Same as Example 1, except that: no plant tannin-polyglutamic acid composite fixative is added to the S2 finishing solution formula, and only the cross-linking system is used to fix the functional components.

[0043] Comparative Example 4 Same as Example 1, except that: S3 adopts the traditional single-stage immersion rolling process: finishing liquid temperature 60℃, immersion rolling time 15min, rolling residue rate 75%, without performing the second stage temperature control directional distribution treatment.

[0044] Comparative Example 5 Same as Example 1, except that: S4 adopts the traditional one-step curing process: directly cures at 150°C for 10 min, without performing three-stage gradient curing.

[0045] Comparative Example 6: Traditional Citric Acid Crosslinking Finishing Process Finishing solution formula: 30 parts citric acid, 8 parts sodium hypophosphite, 5 parts softener, add water to 1000 parts; Rolling: Rolling allowance 75%; Curing: 150℃, 5 min; Post-processing: routine washing and drying.

[0046] Comparative Example 7: Traditional Antibacterial and Mosquito-Repellent Finishing Process Finishing solution formula: 20 parts of commercially available quaternary ammonium salt antibacterial agent, 15 parts of synthetic mosquito repellent DEET, 10 parts of fixative, add water to 1000 parts; Rolling: Rolling allowance 70%; Curing: 130℃, 3 min; Post-processing: routine washing and drying.

[0047] Test case 1. Antigen fibrinolytic properties Pilling grade: According to GB / T 4802.1-2008 standard, the circular trajectory method is used for testing, and the grade is determined after 20 washes. Tensile strength retention rate: Tested according to GB / T 3923.1-2013 standard, comparing before and after 20 water washes.

[0048] 2. Antibacterial properties Antibacterial rate: The antibacterial rate against Staphylococcus aureus, Escherichia coli and Candida albicans was tested according to GB / T 20944.3-2008 standard; Wash fastness: The antibacterial rate was tested after 50 washes according to the standard GB / T 3920-2008 "Textiles - Tests for color fastness to washing".

[0049] 3. Mosquito repellent properties Repellency rate: The repellency rate against Aedes aegypti and Culex pipiens pallens was tested according to GB / T 30126-2013 standard. Wash fastness: The repellency rate was tested after 50 washes according to GB / T 12490 "Test method for color fastness of textiles to domestic and commercial washing".

[0050] 4. Physical properties Flexibility: The bending stiffness is tested according to GB / T 18318.1-2009 standard; the smaller the value, the more flexible the material. Hygroscopicity: The water absorption rate was tested according to GB / T 21655.1-2008 standard; Breathability: The breathability rate was tested according to GB / T 5453-2019 standard.

[0051] 5. Degree of crosslinking determination The degree of crosslinking of cellulose was determined using the formamide dissolution method.

[0052] 6. Safety Performance Silver content: The silver content on the fabric surface was determined by ICP-MS. Skin irritation: Closed patch test was performed according to GB / T 21557-2008 standard.

[0053] Table 1 Results of Antigen Fibrosis Performance Test Note: Different superscript letters in the same column indicate significant differences (P<0.05), while the same letters indicate no significant differences (P≥0.05).

[0054] Table 2. Antibacterial performance (initial / after 50 washes) test results Note: Different superscript letters in the same column indicate significant differences (P<0.05), while the same letters indicate no significant differences (P≥0.05).

[0055] Table 3. Mosquito repellency performance (initial / after 50 washes) test results Note: Different superscript letters in the same column indicate significant differences (P<0.05), while the same letters indicate no significant differences (P≥0.05).

[0056] Table 4 Physical performance test results Note: Different superscript letters in the same column indicate significant differences (P<0.05), while the same letters indicate no significant differences (P≥0.05).

[0057] Table 5 Safety Performance Test Results Note: Different superscript letters in the same column indicate significant differences (P<0.05), while the same letters indicate no significant differences (P≥0.05).

[0058] In terms of antigen fibrillation performance, Examples 1, 3, 5, 7, 9 and 11 all achieved a pilling grade of 4.0, with a breaking strength retention rate between 92.5% and 94.5%, which was significantly better than the comparative examples. Among them, Comparative Example 1 had the worst performance due to the omission of the enzyme treatment step, and the traditional antibacterial and mosquito-repellent finishing of Comparative Example 7 was only grade 1.5 and 78.2%, indicating that the micro-pit structure and gradient cross-linking network constructed by enzyme treatment played a key role in improving antigen fibrillation performance.

[0059] Regarding antibacterial performance, all examples showed an initial inhibition rate of over 99% against the three test bacteria, and maintained a level of 68.8%-83.5% after 50 washes. Example 3 performed best due to the highest dosage of gradient crosslinking components and antibacterial and mosquito-repellent components, achieving an inhibition rate of 81.2%-83.5% after washing. Comparative Example 2, lacking the addition of bridged bicyclodextrin inclusion complex, exhibited extremely poor antibacterial performance, initially only 52.8%-58.5%, and further decreased by 24.5%-28.5% after washing. Comparative Example 3, without the use of plant tannin-polyglutamic acid composite fixative, although showing a decent initial inhibition rate (94.5%-96.5%), exhibited poor wash resistance, with only 35.5%-38.5% remaining after 50 washes, fully demonstrating the importance of composite fixative in improving functional durability.

[0060] The mosquito repellency test results showed a similar trend to the antibacterial performance. The initial repellency rate of the examples was between 89.5% and 95.8%, and remained between 60.5% and 72.5% after 50 washes. In contrast, Comparative Examples 2 and 6 had almost no mosquito repellency effect because no relevant components were added, and Comparative Example 7 had a certain initial effect but extremely poor wash resistance.

[0061] Physical performance data show that the present invention achieves both functionality and comfort. The bending stiffness of the embodiment is controlled between 265-305 mN·cm, which is significantly lower than 425 mN·cm of Comparative Example 6, indicating that gradient crosslinking effectively improves the softness of the fabric. In terms of moisture absorption, the embodiment maintains a good level of 178%-195%, which is only slightly lower than Comparative Example 7 and much higher than 152% of Comparative Example 6. The air permeability is maintained in an excellent range of 412-438 mm / s.

[0062] Safety performance tests showed that the silver content in all embodiments was controlled within the safe range of 6.2-12.8 ppm and there was no skin irritation. Only Comparative Example 6 caused mild irritation due to its high degree of cross-linking and residual chemicals.

[0063] Comparison of examples with different process parameters shows that optimization of the amount of gradient crosslinking component and antibacterial and mosquito-repellent component (Examples 2, 1, 3), enzyme treatment conditions (Examples 4, 1, 5), padding process (Examples 6, 1, 7), curing process (Examples 8, 1, 9), and formulation process (Examples 10, 1, 11) all have a significant impact on the final performance. Among them, the intermediate parameter configuration of Example 1 achieved the best balance between functionality and comfort, while Examples 3 and 9 performed best in terms of functionality but slightly reduced softness. Examples 2 and 10 achieved better softness and breathability while ensuring basic functions.

[0064] In summary, this invention successfully solves the technical problem of balancing functionality and comfort in traditional finishing methods through the synergistic effect of gradient cross-linking technology, natural active ingredient inclusion and sustained-release system, and enzyme-treated microstructure construction.

[0065] Although the process of this invention is more expensive than traditional processes, it integrates multiple functions such as anti-fibrillation, antibacterial properties, and mosquito repellency. Even after 50 washes, it maintains an antibacterial rate of over 70% and a repellency rate of over 60%, while also preserving excellent softness and comfort. This comprehensive performance improvement is difficult to achieve with traditional single-function finishing methods. With the upgrading of consumption, the demand for high-quality functional textiles from mid-to-high-end consumers continues to grow, especially in niche markets such as summer clothing, outdoor sports, and maternity and baby products, showing promising prospects. Furthermore, this process uses natural plant-derived ingredients instead of chemically synthesized reagents, aligning with the trend of green and sustainable development. From a life-cycle perspective, due to its superior functional durability, it offers better overall cost-effectiveness compared to ordinary products that require frequent replacement.

[0066] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a lightweight Lyocell cotton denim fabric with both low fibrillation and antibacterial / mosquito-repellent properties, characterized in that, Includes the following steps: S1. Fabric pretreatment: Enzyme treatment is performed on Lyocell cotton denim, followed by enzyme inactivation and washing with water. S2. Preparation of finishing solution: Prepare a gradient functional finishing working solution containing gradient cross-linking components, antibacterial and mosquito-repellent components and synergistic components; The gradient functional finishing working solution comprises, by weight, 33-64 parts of gradient cross-linking component, 30-50 parts of antibacterial and mosquito-repellent component, 12-24 parts of synergistic component, and water to a total of 1000 parts. The gradient crosslinking component includes 10-18 parts of citric acid, 3-8 parts of maleic acid, 8-14 parts of nano-modified chitosan, 4-9 parts of crosslinking catalyst, and 8-15 parts of nano-plant wax emulsion. The antibacterial and mosquito-repellent components include 18-30 parts of bridged bicyclodextrin inclusion complex, 7-12 parts of plant tannin-polyglutamic acid composite fixative, and 5-8 parts of cross-linked modified starch nanocarrier. The synergistic effect-enhancing components include 3-6 parts of metal ion chelating agent, 1.5-3 parts of antioxidant, 6-12 parts of moisturizing stabilizer, and 2-5 parts of penetration enhancer; S3, Two-stage padding: The finishing working solution is applied to the fabric using a two-stage padding process to form a gradient distribution of functional components; S4, Three-stage curing: The impregnated fabric is pre-dried, medium-temperature baked and zoned high-temperature cured in sequence to construct a gradient cross-linking network; S5. Finishing: The cured fabric is washed, dried and functionally protected to obtain lightweight Lyocell cotton denim with low fibrillation and antibacterial and mosquito-repellent functions.

2. The preparation method according to claim 1, characterized in that, In step S1, the enzyme treatment process conditions are as follows: neutral cellulase is used, with an enzyme activity of 2000-4000 U / g, a dosage of 0.3-0.8% wf, a liquor ratio of 1:(12-16), a temperature of 45-52℃, a pH of 6.0-7.0, a treatment time of 20-35 min, the depth of the micro-pits is 0.3-0.8 µm, and the surface roughness Ra value of the fabric after treatment is 1.5-2.5 µm.

3. The preparation method according to claim 1, characterized in that, In step S2, the degree of deacetylation of the nano-modified chitosan is 75-85%, the particle size is 150-350 nm, the modification method is carboxymethylation modification, and the degree of substitution is 0.4-0.8; the crosslinking catalyst is a mixture of sodium hypophosphite and magnesium sulfate in a mass ratio of (3-5):1; the particle size of the nano-plant wax emulsion is 80-200 nm, and the solid content is 25-35%; the bridged bicyclodextrin inclusion complex consists of mosquito-repellent components encapsulated in the inner cavity and antibacterial components adsorbed in the outer cavity; the inner cavity diameter of the bridged bicyclodextrin is 6.5-7.8 Å, the outer cavity has carboxylation modification, the degree of carboxylation is 15-25%, and the bridging group is adipic acid or succinic acid.

4. The preparation method according to claim 3, characterized in that, The mosquito-repellent components include 35-45% mugwort essential oil, 25-35% neem seed oil, and 25-35% lemongrass essential oil; the antibacterial components include 20-30% rosemary extract, 15-25% thyme essential oil, 20-30% cinnamon extract, and 25-35% nano-silver-chitosan complex, wherein the silver content is 200-500 ppm.

5. The preparation method according to claim 1, characterized in that, In step S2, the plant tannin-polyglutamic acid composite fixative is an electrostatic complex formed by the reaction of plant tannin and polyglutamic acid under pH 5.0-5.5 conditions. The plant tannin is a hydrolyzed tannin with a gallic acid content ≥60%, and the polyglutamic acid has a molecular weight of 50,000-100,000. The mass ratio of the two is (2-3):

1. The cross-linked modified starch nanocarrier is modified by acetic acid esterification with a degree of substitution of 0.5-1.2 and an amount of 3-6% of the starch mass. The particle size of the cross-linked modified starch nanocarrier is 100-300 nm.

6. The preparation method according to claim 1, characterized in that, In step S2, the preparation method of the gradient function conditioning working solution includes the following steps: (1) Pre-inclusion reaction: The mosquito repellent component is mixed with bridged bicyclodextrin to form an inner cavity inclusion complex; (2) Adsorption of antibacterial components: The antibacterial components are added to the product of step (1), and the mixture is stirred to react, so as to obtain a bifunctional inclusion complex with both mosquito repellent and antibacterial functions. (3) Fixative compound: In a separate system, plant tannins and polyglutamic acid are mixed and the pH value is controlled at 5.0-5.5 to react and form an electrostatic complex; (4) Construction of the main system: Citric acid, maleic acid, cross-linking catalyst and nano-modified chitosan are mixed to form the main system for cross-linking reaction; (5) Maturation: Add the bifunctional inclusion complex from step (2) and the electrostatic complex from step (3) to the main system of step (4), and add the cross-linked modified starch nanocarrier, nano plant wax emulsion and synergistic component in sequence. Adjust the pH to 4.8-5.5 with citric acid / sodium citrate buffer, let the temperature drop naturally to 25-35℃, and let it stand to mature to obtain the finishing working solution.

7. The preparation method according to claim 1, characterized in that, In step S3, the two-stage immersion rolling process includes: the temperature of the first stage finishing liquid is 55-65℃, the immersion rolling time is 12-18 min, and the rolling yield is 70-80%; the temperature of the second stage finishing liquid is 45-55℃, the immersion rolling time is 8-15 min, and the rolling yield is reduced to 55-70%.

8. The preparation method according to claim 1, characterized in that, The three-stage curing process in step S4 includes: a pre-drying stage at a temperature of 65-75℃ for 4-7 minutes, with a fabric moisture regain of 35-45%; a medium-temperature baking stage at a temperature of 95-108℃ for 5-9 minutes; and a high-temperature curing stage at a temperature of 135-142℃ in the first zone, 142-150℃ in the second zone, and 148-155℃ in the third zone, with a total time of 4-7 minutes.

9. The preparation method according to claim 1, characterized in that, The post-treatment in step S5 includes two parts: washing and functional protection finishing.

10. The Lyocell cotton denim fabric prepared by the method according to any one of claims 1-9 is characterized in that, The Lyocell cotton denim fabric has a three-dimensional gradient network structure from the outside to the inside, including a surface protective layer, an internal cross-linking layer, and a slow-release regulating layer that runs through the fibers. The surface protective layer is located within a depth range of 0-2 µm on the fiber surface. It is composed of an enriched chitosan-plant tannin composite membrane, nano-plant wax and cyclodextrin inclusion complex. It increases the specific surface area through micro-pits, enhances the durability of function, presents a continuous and dense membrane structure, fills and retains some micro-pits, and the pit depth is 0.3-0.8 µm. The internal cross-linking layer is located within a depth range of 2-10 µm in the fiber, has a citric acid-maleic acid synergistic cross-linking network, and has a cross-linking degree of 12-25%, exhibiting a three-dimensional network cross-linking structure. The sustained-release control layer that runs through the fiber consists of cross-linked modified starch nanocarriers and cyclodextrin inclusion complexes dispersed inside the fiber, with a concentration gradient distribution from the fiber surface to the core, and the nanoparticles have a size of 100-350 nm.

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