Warm-keeping and breathable blend fiber, treating agent and application of warm-keeping and breathable blend fiber

Abstract

The invention discloses a warm-keeping and breathable blend fiber, a treating agent and application of the warm-keeping and breathable blend fiber, and belongs to the technical field of textile fabrics. The preparation method comprises the steps of fiber pretreatment, wool grafting, kapok surface treatment, blending weaving and after-treatment. According to the invention, the natural heat retention property of wool is combined with the high-pore structure of kapok, and a dual mechanism of physical heat retention and dynamic temperature control is formed through lignin nanosphere grafting and phase change microcapsule finishing. The lignin nanospheres take industrial wastes as raw materials, and conform to the concept of circular economy; and a closed isocyanate cross-linking agent is adopted in the after-finishing process, so that the release of free formaldehyde is reduced.

Description

Technical Field

[0001] This invention relates to the field of textile fabric technology, specifically to a warm and breathable blended fiber, a treatment agent, and their applications. Background Technology

[0002] Blended fibers exhibit unique advantages in warmth retention and breathability through the synergistic effect of multiple components. The core principle lies in utilizing the physicochemical properties of different fibers, achieving functional complementarity through structural design and process optimization.

[0003] The warmth retention of blended fibers stems from the material's effective barrier against heat transfer. Firstly, the formation of an air layer is a key mechanism. For example, the natural crimp structure of wool fibers can form a 0.8mm air insulation layer, improving static insulation efficiency by 42% compared to pure cotton. Hollow fibers manufactured through blending spinning technology, when filled with nitrogen, exhibit further reduced thermal conductivity, significantly enhancing their warmth retention. Secondly, the moisture absorption and heat release effects also play a supporting role.

[0004] In terms of material selection, blending high-loft fibers is an important strategy. For example, blends of acrylic and wool (such as Derong) achieve a loft of 1.7 times that of conventional products through microfiber design and surface brushing processes, maintaining a perceived temperature fluctuation of no more than 1.2°C for 8 hours at -15°C. New composite materials, such as volcanic rock aerogel blended cotton, improve warmth retention by 5-10% through a nanoscale porous structure while achieving lightweighting.

[0005] Breathability is achieved through the synergistic effect of moisture absorption and wicking combined with microporous diffusion. Natural fibers like cotton have hydrophilic hydroxyl groups (-OH) that adsorb water molecules via hydrogen bonds, forming moisture-wicking channels in conjunction with the porous structure of cellulose fibers. Synthetic fibers, on the other hand, increase surface area through irregular cross-sectional designs (such as Y-shaped and cross-shaped designs) to promote sweat evaporation.

[0006] Microporous membrane technology represents a significant breakthrough in improving breathability. Fluorine-free microporous membranes, with their 0.5-2μm mesh-like pores, can block liquid water (diameter > 100μm) while allowing water vapor (0.0004μm) to diffuse freely, representing a 35% improvement over traditional PU membranes. Furthermore, precise control of the blending ratio is crucial. For example, when blending lyocell with nylon, the high moisture absorption of lyocell (13%) and the hydrophobicity of nylon (4.5%) need to be balanced through ratio optimization to optimize breathability and antistatic properties.

[0007] Current blending technology is trending towards more complex materials and more refined processes. At the material level, multi-component synergistic design has become mainstream. For example, wool / silk / acrylic triple-layer blended fibers achieve a balance between warmth and breathability through the skin-friendly layer of silk, the air layer of wool, and the supporting structure of acrylic. Breakthroughs have also been made in eco-friendly technologies, such as using recycled polyester blended with organic cotton, combined with fluorine-free dyeing processes, resulting in products that have passed GRS certification and achieve a breathability of 180mm / s.

[0008] Despite significant progress in blending technology, its performance remains constrained by the conflicting physicochemical properties of the materials. For example, while cotton-polyester blends (30-50% cotton) combine moisture absorption and abrasion resistance, their shrinkage rate still reaches 2-4%, requiring pre-shrinking treatment for control. When blending lyocell and nylon, the uneven stress caused by the difference in their moisture absorption rates can lead to fabric distortion, and the conflicting dyeing processes (alkaline vs. acidic conditions) are difficult to reconcile.

[0009] The complexity of the production process is also a significant challenge. For example, separating waste polyester-cotton blended fabrics requires selective hydrolysis, which is costly and results in a fiber damage rate of up to 10%. Furthermore, the large-scale application of high-performance materials (such as aerogels) is limited by processing difficulties and is currently only used in small quantities in high-end outdoor clothing.

[0010] From an environmental perspective, the use of chemical treatment agents remains controversial. Traditional waterproofing finishing agents containing fluorinated compounds (PFAS) may have long-term environmental impacts, while the durability of fluorine-free alternatives (such as hyperbranched polymer coatings) still needs improvement.

[0011] To overcome existing limitations, research focuses on biomimetic design and intelligent responsive materials. For example, mimicking the hollow structure of polar bear fur, fibers that adapt to temperature changes (such as hollow fibers encapsulated by thermosensitive polymers) are being developed, dynamically adjusting their warmth retention within a temperature range of -10°C to 25°C. Furthermore, bio-based blended materials (such as blends of avocado fiber and modal) enhance skin-friendliness through plant-derived components while simultaneously achieving biodegradability.

[0012] The development of blended fibers demonstrates the value of "synergistic effects" in materials science. By precisely controlling the physical structure and chemical composition of fibers, blending technology has continuously made breakthroughs in balancing warmth and breathability, but it also faces challenges such as conflicting material properties and environmental constraints. In the future, with the integration of bionics, nanotechnology, and smart materials, blended fibers are expected to achieve new leaps in functional integration and sustainability. Summary of the Invention

[0013] The purpose of this invention is to provide a warm and breathable blended fiber, a treatment agent, and its application to solve the problems mentioned in the background art.

[0014] A method for preparing a warm and breathable blended fiber includes the following steps:

[0015] S1 fiber pretreatment: Soak wool and kapok fibers in an alkaline solution, then wash until neutral, and dry for later use;

[0016] S2 Wool Grafting: Hollow lignin nanospheres are grafted onto wool through a grafting reaction to obtain grafted wool;

[0017] S3 Kapok Surface Treatment: After the kapok fibers are activated, a hydrophilic polymer grafting solution is prepared. The activated kapok is immersed in the solution and the hydrophilic polymer segments are grafted onto the kapok through free radical polymerization to obtain grafted kapok.

[0018] S4 blended fabrication: grafted wool and grafted kapok are opened separately, with grafted wool having fibers ≤20mm in length removed; grafted kapok having fibers ≤15mm in length removed.

[0019] Grafted wool and grafted kapok are mixed at a mass ratio of 6.5-7.5:2.5-3.5, then combed, spun, and woven to obtain a preliminary blended fabric;

[0020] S5 finishing: Immerse the initial blended fabric in the finishing solution, then dip and rub twice; then dry.

[0021] The finishing solution comprises at least the following components by mass percentage:

[0022]

[0023]

[0024] The core material of the phase change microcapsule heat preservation agent is n-octadecane, and the phase change temperature range is 28-32℃.

[0025] Preferably, the method for preparing the hollow lignin nanospheres is as follows:

[0026] Lignin is dissolved in a good solvent to prepare a solution; while stirring, a poor solvent is added dropwise to the solution to initiate self-assembly;

[0027] After self-assembly, the good solvent is removed, and then the nanospheres are collected by centrifugation and washed to obtain hollow lignin nanospheres.

[0028] The good solvent and the bad solvent are miscible;

[0029] The concentration of the solution is ≤5mg / mL; the stirring rate when the undesirable solvent is added is ≥500rpm and the dropping rate is ≤2mL / min.

[0030] Preferably, in step S2, wool grafting, the following is performed:

[0031] The wool is added to the dispersion, stirred at a constant temperature to induce a grafting reaction, and then dried after the reaction is complete.

[0032] The dispersion contains at least the following components by mass percentage:

[0033] Hollow lignin nanospheres ≥5

[0034] 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide ≥0.5

[0035] N-hydroxysuccinimide ≥0.3

[0036] The bath ratio of wool is 1:≥40; the pH of the dispersion is≤5.5; the temperature of constant temperature stirring is≥50℃, and the time is≥3h.

[0037] Preferably, in the S3 kapok surface treatment:

[0038] Kapok fibers are etched with cellulase before activation;

[0039] The hydrophilic polymer grafting solution shall include at least the following components by mass percentage:

[0040]

[0041] When immersing the activated kapok in the solution, the temperature should be ≥60℃, and stirring should be maintained for at least 2 hours; the bath ratio of the kapok should be 1:≥50.

[0042] After grafting, wash and dry to obtain grafted kapok.

[0043] Preferably, in the S5 finishing process, the softener is a silicone-based softener; and the crosslinking agent is a blocked isocyanate.

[0044] The present invention also provides a treatment agent comprising at least the following components by mass percentage:

[0045] Hollow lignin nanospheres ≥5

[0046] 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide ≥0.5

[0047] N-hydroxysuccinimide ≥0.3

[0048] The solvent for the treatment agent is water; the preparation method of the hollow lignin nanospheres is as follows:

[0049] Lignin is dissolved in a good solvent to prepare a solution; while stirring, a poor solvent is added dropwise to the solution to initiate self-assembly;

[0050] After self-assembly, the good solvent is removed, and then the nanospheres are collected by centrifugation and washed to obtain hollow lignin nanospheres.

[0051] The good solvent and the bad solvent are miscible.

[0052] This invention enhances static insulation by grafting hollow lignin nanospheres onto wool, improves moisture permeability by grafting kapok with hydrophilic polymers, and achieves complementary advantages and synergistic functions of various natural materials through precision blending and functional finishing, ultimately obtaining a high-value-added product with excellent performance and durability.

[0053] This invention provides a method for preparing hollow lignin nanospheres. Its advantages lie in its simple, mild, and efficient preparation conditions; and it creatively utilizes lignin, a renewable and low-cost biomass resource, to construct hollow nanostructures with excellent thermal insulation properties, laying a green and efficient material foundation for the entire approach.

[0054] Furthermore, this invention optimizes the preparation process parameters of hollow lignin nanospheres. By precisely controlling key variables such as solution concentration, stirring rate, and dropping speed, the controllability and repeatability of the nanosphere self-assembly process are ensured, thereby enabling stable mass production of nanospheres with uniform size and complete structure, guaranteeing the stability of subsequent grafting effects and the final product performance.

[0055] To ensure the secure grafting of nanospheres onto wool, the highly efficient carboxyl-amino coupling chemical strategy of EDC / NHS was employed. This strategy achieved covalent bonding between the hollow lignin nanospheres and wool protein. This grafting method is far more robust than physical adsorption, ensuring the durability of the modified wool's thermal insulation function and its resistance to subsequent processing and washing.

[0056] This invention addresses the defects of kapok fiber by first etching and activating the surface with cellulase, and then grafting hydrophilic polymer chains (PEG and acrylamide) through free radical polymerization. This solves the core problems of kapok fiber being smooth, difficult to spin, and having poor moisture absorption, transforming it into a highly absorbent and breathable functional component, which is the key to achieving breathable and comfortable fabrics.

[0057] This invention also optimizes the selection of components for the finishing liquid. The use of silicone softener can greatly improve the fabric feel and enhance wearing comfort; while the selection of closed isocyanate as a crosslinking agent ensures the durability of functional finishing agents (microcapsules, polyurethane) while solving the problems of production safety and environmental protection (non-toxic at room temperature, reacting only at high temperatures), reflecting a comprehensive consideration of process feasibility.

[0058] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention utilizes the natural warmth-retaining properties of wool combined with the high porosity structure of kapok, and through lignin nanosphere grafting and phase change microcapsule finishing, forms a dual mechanism of "physical warmth retention and dynamic temperature control". The lignin nanospheres are made from industrial waste, which conforms to the concept of circular economy; the finishing process uses a closed isocyanate crosslinking agent to reduce the release of free formaldehyde. Detailed Implementation

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Example 1: Preparation of hollow lignin nanospheres, comprising the following steps:

[0061] S1: Take alkali lignin and put it into tetrahydrofuran to prepare a solution with a concentration of 5 mg / mL. Stir magnetically and sonicate until the alkali lignin is completely dissolved.

[0062] S2: While maintaining a rotation speed of 500 rpm, slowly add deionized water dropwise into the alkali lignin solution using a syringe pump. The dropping rate should be controlled at an average of 1 mL / min, and at a maximum of no more than 2 mL / min.

[0063] After adding deionized water dropwise to a volume ratio of 1:1 with the alkali lignin solution, stop adding water dropwise after each drop of 3% alkali lignin solution is added and observe the system. The self-assembly is complete when the turbidity or opalescence of the system no longer changes.

[0064] S3: Transfer the mixed liquid to a dialysis bag and dialyze with deionized water until all tetrahydrofuran is removed to obtain a suspension;

[0065] S4: Centrifuge the suspension at 10,000 rpm for 30 min; collect the nanospheres, wash them with deionized water, freeze-dry and seal them for storage to obtain hollow lignin nanospheres.

[0066] Example 2: A method for preparing blended fibers, comprising the following steps:

[0067] S1 fiber pretreatment: Place wool in 5% NaOH solution, soak at 40℃ for 30 minutes (liquor ratio 1:50) to remove surface grease and impurities, wash with deionized water until neutral, and dry at 60℃ for later use;

[0068] Kapok fibers were placed in a 2% NaOH solution and boiled at 90°C for 40 minutes (liquor ratio 1:60) to remove surface wax and pectin. They were then washed until neutral and dried at 660°C for later use.

[0069] S2 Wool Grafting: Wool is placed in a dispersion (bath ratio of 1:40) and the pH is adjusted to 5.5; the grafting reaction is carried out at 50°C with constant stirring (200 rpm) for 3 hours. After grafting, the wool is washed three times with deionized water and dried at 60°C to obtain grafted wool.

[0070] The dispersion contains the following components by mass percentage:

[0071]

[0072] S3 Kapok Surface Treatment: Pretreated kapok was soaked (bath ratio 1:50) in a 0.5% (w / w) cellulase solution (pH 4.8) and treated with constant temperature shaking at 50°C for 1 hour (rotation speed 150 r / min).

[0073] The enzymatically hydrolyzed kapok was placed in a plasma treatment instrument, argon gas was introduced (flow rate 20 sccm), power 100W, and treatment time 3 min;

[0074] Then, the pretreated kapok fibers were immersed in the hydrophilic polymer grafting solution at a bath ratio of 1:50, and stirred to ensure that the fibers were completely wetted.

[0075] Place the reaction vessel in a constant temperature water bath, heat it to 60℃, and stir the reaction for 2 hours (200 rpm).

[0076] During the reaction, samples were taken every 30 minutes to avoid local overheating that could lead to monomer self-polymerization (if white flocculent material appears, the temperature should be reduced by 5°C); after the reaction, the kapok fibers were washed three times with deionized water and dried at 60°C to obtain grafted kapok.

[0077] The hydrophilic polymer grafting solution contains the following components by mass percentage:

[0078]

[0079] S4 blended fabrication: grafted wool and grafted kapok are opened separately, with grafted wool having fibers ≤20mm in length removed; grafted kapok having fibers ≤15mm in length removed.

[0080] Grafted wool and grafted kapok were mixed three times in a blender at a mass ratio of 6.5:3.5.

[0081] Carding: The carding machine operates at a speed of 300 r / min to produce cotton slivers;

[0082] Spinning: Ring spinning is adopted, with a draft ratio of 50 times and a twist of 800 twists / m to produce 32s blended yarn;

[0083] Fabric weaving: Using an air-jet loom, weave a plain weave fabric (warp density 280 threads / 10cm, weft density 240 threads / 10cm) to obtain the initial blended fabric;

[0084] S5 finishing: The initial blended fabric is immersed in the finishing solution and a two-dip two-ply process is adopted. The ply rate is controlled at 75%. Then, it is pre-dried at 95℃ for 3 minutes and then baked at 165℃ for 2 minutes to obtain the blended fabric.

[0085] The finishing solution contains the following components by weight percentage:

[0086]

[0087] The core material of the PCM phase change microcapsule is n-octadecane, and the phase change temperature range is 28°C.

[0088] Example 3: Preparation method of mixed fibers

[0089] The difference from Example 2 is that in step SS4 of the blended weaving process, the grafted wool and grafted kapok are mixed in a mass ratio of 7.5:2.5.

[0090] Example 4: A method for preparing blended fibers, comprising the following steps:

[0091] S1 fiber pretreatment: Place wool in 5% NaOH solution, soak at 40℃ for 30 minutes (liquor ratio 1:50) to remove surface grease and impurities, wash with deionized water until neutral, and dry at 60℃ for later use;

[0092] Kapok fibers were placed in a 2% NaOH solution and boiled at 90°C for 40 minutes (liquor ratio 1:60) to remove surface wax and pectin. They were then washed until neutral and dried at 660°C for later use.

[0093] S2 Kapok Surface Treatment: The pretreated kapok was soaked (bath ratio 1:50) in a 0.5% (w / w) cellulase solution (pH 4.8) and treated with constant temperature shaking at 50°C for 1 hour (rotation speed 150 r / min).

[0094] The enzymatically hydrolyzed kapok was placed in a plasma treatment instrument, argon gas was introduced (flow rate 20 sccm), power 100W, and treatment time 3 min;

[0095] Then, the pretreated kapok fibers were immersed in the hydrophilic polymer grafting solution at a bath ratio of 1:50, and stirred to ensure that the fibers were completely wetted.

[0096] Place the reaction vessel in a constant temperature water bath, heat it to 60℃, and stir the reaction for 2 hours (200 rpm).

[0097] During the reaction, samples were taken every 30 minutes to avoid local overheating that could lead to monomer self-polymerization (if white flocculent material appears, the temperature should be reduced by 5°C); after the reaction, the kapok fibers were washed three times with deionized water and dried at 60°C to obtain grafted kapok.

[0098] The hydrophilic polymer grafting solution contains the following components by mass percentage:

[0099]

[0100] S3 blended fabrication: wool and grafted kapok are opened separately, with wool having fibers ≤20mm in length removed; and grafted kapok having fibers ≤15mm in length removed.

[0101] Wool and grafted kapok are mixed three times in a blender at a mass ratio of 6.5:3.5.

[0102] Carding: The carding machine operates at a speed of 300 r / min to produce cotton slivers;

[0103] Spinning: Ring spinning is adopted, with a draft ratio of 50 times and a twist of 800 twists / m to produce 32s blended yarn;

[0104] Fabric weaving: Using an air-jet loom, weave a plain weave fabric (warp density 280 threads / 10cm, weft density 240 threads / 10cm) to obtain the initial blended fabric;

[0105] S5 finishing: The initial blended fabric is immersed in the finishing solution and a two-dip two-ply process is adopted. The ply rate is controlled at 75%. Then, it is pre-dried at 95℃ for 3 minutes and then baked at 165℃ for 2 minutes to obtain the blended fabric.

[0106] The finishing solution contains the following components by weight percentage:

[0107]

[0108]

[0109] The core material of the PCM phase change microcapsule is n-octadecane, and the phase change temperature range is 28°C.

[0110] Example 5: A method for preparing blended fibers, comprising the following steps:

[0111] S1 fiber pretreatment: Place wool in 5% NaOH solution, soak at 40℃ for 30 minutes (liquor ratio 1:50) to remove surface grease and impurities, wash with deionized water until neutral, and dry at 60℃ for later use;

[0112] Kapok fibers were placed in a 2% NaOH solution and boiled at 90°C for 40 minutes (liquor ratio 1:60) to remove surface wax and pectin. They were then washed until neutral and dried at 660°C for later use.

[0113] S2 Wool Grafting: Wool is placed in a dispersion (bath ratio of 1:40) and the pH is adjusted to 5.5; the grafting reaction is carried out at 50°C with constant stirring (200 rpm) for 3 hours. After grafting, the wool is washed three times with deionized water and dried at 60°C to obtain grafted wool.

[0114] The dispersion contains the following components by mass percentage:

[0115]

[0116] S3 blended fabrication: grafted wool and kapok are opened separately, with grafted wool having fibers ≤20mm in length removed; kapok having fibers ≤15mm in length removed.

[0117] Grafted wool and kapok were mixed three times in a blender at a mass ratio of 6.5:3.5.

[0118] Carding: The carding machine operates at a speed of 300 r / min to produce cotton slivers;

[0119] Spinning: Ring spinning is adopted, with a draft ratio of 50 times and a twist of 800 twists / m to produce 32s blended yarn;

[0120] Fabric weaving: Using an air-jet loom, weave a plain weave fabric (warp density 280 threads / 10cm, weft density 240 threads / 10cm) to obtain the initial blended fabric;

[0121] S4 finishing: The initial blended fabric is immersed in the finishing solution and a two-dip two-ply process is adopted. The ply rate is controlled at 75%. Then, it is pre-dried at 95℃ for 3 minutes and then baked at 165℃ for 2 minutes to obtain the blended fabric.

[0122] The finishing solution contains the following components by weight percentage:

[0123]

[0124] The core material of the PCM phase change microcapsule is n-octadecane, and the phase change temperature range is 28°C.

[0125] Example 6: A method for preparing blended fibers, comprising the following steps:

[0126] S1 fiber pretreatment: Place wool in 5% NaOH solution, soak at 40℃ for 30 minutes (liquor ratio 1:50) to remove surface grease and impurities, wash with deionized water until neutral, and dry at 60℃ for later use;

[0127] Kapok fibers were placed in a 2% NaOH solution and boiled at 90°C for 40 minutes (liquor ratio 1:60) to remove surface wax and pectin. They were then washed until neutral and dried at 660°C for later use.

[0128] S2 blended fabrication: wool and kapok are opened separately, with wool having fibers ≤20mm in length removed; kapok having fibers ≤15mm in length removed;

[0129] Grafted wool and grafted kapok were mixed three times in a blender at a mass ratio of 6.5:3.5.

[0130] Carding: The carding machine operates at a speed of 300 r / min to produce cotton slivers;

[0131] Spinning: Ring spinning is adopted, with a draft ratio of 50 times and a twist of 800 twists / m to produce 32s blended yarn;

[0132] Fabric weaving: Using an air-jet loom, weave a plain weave fabric (warp density 280 threads / 10cm, weft density 240 threads / 10cm) to obtain the initial blended fabric;

[0133] S3 finishing: The initial blended fabric is immersed in the finishing solution and a two-dip two-ply process is adopted. The ply rate is controlled at 75%. Then, it is pre-dried at 95℃ for 3 minutes and then baked at 165℃ for 2 minutes to obtain the blended fabric.

[0134] The finishing solution contains the following components by weight percentage:

[0135]

[0136] The core material of the PCM phase change microcapsule is n-octadecane, and the phase change temperature range is 28°C.

[0137] Example 7: A method for preparing blended fibers, comprising the following steps:

[0138] S1 fiber pretreatment: Place wool in 5% NaOH solution, soak at 40℃ for 30 minutes (liquor ratio 1:50) to remove surface grease and impurities, wash with deionized water until neutral, and dry at 60℃ for later use;

[0139] Kapok fibers were placed in a 2% NaOH solution and boiled at 90°C for 40 minutes (liquor ratio 1:60) to remove surface wax and pectin. They were then washed until neutral and dried at 660°C for later use.

[0140] S2 Wool Grafting: Wool is placed in a dispersion (bath ratio of 1:40) and the pH is adjusted to 5.5; the grafting reaction is carried out at 50°C with constant stirring (200 rpm) for 3 hours. After grafting, the wool is washed three times with deionized water and dried at 60°C to obtain grafted wool.

[0141] The dispersion contains the following components by mass percentage:

[0142]

[0143]

[0144] S3 Kapok Surface Treatment: Pretreated kapok was soaked (bath ratio 1:50) in a 0.5% (w / w) cellulase solution (pH 4.8) and treated with constant temperature shaking at 50°C for 1 hour (rotation speed 150 r / min).

[0145] The enzymatically hydrolyzed kapok was placed in a plasma treatment instrument, argon gas was introduced (flow rate 20 sccm), power 100W, and treatment time 3 min;

[0146] Then, the pretreated kapok fibers were immersed in the hydrophilic polymer grafting solution at a bath ratio of 1:50, and stirred to ensure that the fibers were completely wetted.

[0147] Place the reaction vessel in a constant temperature water bath, heat it to 60℃, and stir the reaction for 2 hours (200 rpm).

[0148] During the reaction, samples were taken every 30 minutes to avoid local overheating that could lead to monomer self-polymerization (if white flocculent material appears, the temperature should be reduced by 5°C); after the reaction, the kapok fibers were washed three times with deionized water and dried at 60°C to obtain grafted kapok.

[0149] The hydrophilic polymer grafting solution contains the following components by mass percentage:

[0150]

[0151] S4 blended fabrication: grafted wool and grafted kapok are opened separately, with grafted wool having fibers ≤20mm in length removed; grafted kapok having fibers ≤15mm in length removed.

[0152] Grafted wool and grafted kapok were mixed three times in a blender at a mass ratio of 6.5:3.5.

[0153] Carding: The carding machine operates at a speed of 300 r / min to produce cotton slivers;

[0154] Spinning: Ring spinning is adopted, with a draft ratio of 50 times and a twist of 800 twists / m to produce 32s blended yarn;

[0155] Fabric weaving: Using an air-jet loom, weave a plain weave fabric (warp density 280 threads / 10cm, weft density 240 threads / 10cm) to obtain a blended fabric.

[0156] Example 8: A method for preparing blended fibers, comprising the following steps:

[0157] S1 fiber pretreatment: Place wool in 5% NaOH solution, soak at 40℃ for 30 minutes (liquor ratio 1:50) to remove surface grease and impurities, wash with deionized water until neutral, and dry at 60℃ for later use;

[0158] Kapok fibers were placed in a 2% NaOH solution and boiled at 90°C for 40 minutes (liquor ratio 1:60) to remove surface wax and pectin. They were then washed until neutral and dried at 660°C for later use.

[0159] S2 blended fabrication: wool and kapok are opened separately, with wool having fibers ≤20mm in length removed; kapok having fibers ≤15mm in length removed;

[0160] Wool and kapok are mixed three times in a blender at a mass ratio of 6.5:3.5.

[0161] Carding: The carding machine operates at a speed of 300 r / min to produce cotton slivers;

[0162] Spinning: Ring spinning is adopted, with a draft ratio of 50 times and a twist of 800 twists / m to produce 32s blended yarn;

[0163] Fabric weaving: Using an air-jet loom, weave a plain weave fabric (warp density 280 threads / 10cm, weft density 240 threads / 10cm) to obtain a blended fabric.

[0164] Example 9: A method for preparing wool fabric, comprising the following steps:

[0165] S1 fiber pretreatment: Place wool in 5% NaOH solution, soak at 40℃ for 30 minutes (liquor ratio 1:50) to remove surface grease and impurities, wash with deionized water until neutral, and dry at 60℃ for later use;

[0166] S2 Wool Grafting: Wool is placed in a dispersion (bath ratio of 1:40) and the pH is adjusted to 5.5; the grafting reaction is carried out at 50°C with constant stirring (200 rpm) for 3 hours. After grafting, the wool is washed three times with deionized water and dried at 60°C to obtain grafted wool.

[0167] The dispersion contains the following components by mass percentage:

[0168]

[0169] S4 weaving: Grafted wool is opened and fibers with a length ≤20mm are removed;

[0170] Carding: The carding machine operates at a speed of 300 r / min to produce cotton slivers;

[0171] Spinning: Ring spinning is adopted, with a draft ratio of 50 times and a twist of 800 twists / m to produce 32s yarn;

[0172] Fabric weaving: Using an air-jet loom, weave a plain weave fabric (280 warp threads / 10cm, 240 weft threads / 10cm) to obtain wool fabric.

[0173] Performance testing

[0174] The performance of the fiber fabrics prepared in Examples 2-9 above was tested, specifically as follows:

[0175] Thermal insulation: Tested according to the method of GB / T 11048-2018 Determination of thermal and moisture resistance of textiles under steady-state conditions for physiological comfort (evaporative hot plate method).

[0176] Air permeability: Tested according to the method of GB / T 5453-1997 Textiles, Fabrics, Determination of air permeability.

[0177] Wash resistance test: Following the method described in GB / T 8629-2017 "Test Procedures for Household Washing and Drying of Textiles", the product was washed 50 times in Program 5A; then, the warmth retention and breathability tests were conducted again. The results are shown in Table 1 below:

[0178] Table 1

[0179]

[0180] In Table 1, the higher the thermal resistance (Rct), the better the insulation. The key factors affecting thermal resistance are the material's ability to trap still air and its own thermal insulation properties.

[0181] The difference in thermal resistance between Examples 2 and 3 is due to the blending ratio; wool fibers are naturally crimped and have scales on their surface, which allows them to form more and more stable pockets of still air within the fiber aggregate. Air is an excellent insulator. The higher the wool content, the more still air is trapped within the fiber aggregate, resulting in higher thermal resistance and better warmth retention.

[0182] Examples 2, 4, and 5 differ in their grafting targets. In Example 2, both the hollow lignin nanospheres grafted onto wool and the hydrophilic polymer grafted onto kapok increased the surface roughness and thickness of the fibers, increasing the complexity of the heat conduction path and thus improving insulation. The combined effect of both was the best. In Example 5, only wool was grafted with hollow lignin nanospheres. The nanospheres themselves have a hollow structure, which effectively hinders heat conduction, thus resulting in a higher thermal resistance than ungrafted wool (see Example 8). In Example 4, only kapok was grafted with a hydrophilic polymer. Kapok fibers themselves are hollow and have good heat retention potential, but the polymer layer grafted onto its surface is relatively dense, contributing less to improving insulation than the hollow nanospheres.

[0183] Compared to Example 6, Example 2's grafting process introduced an additional layer of heat-insulating material (nanospheres and polymers) onto the fiber surface, significantly improving the overall thermal resistance of the fabric. In contrast, the fibers in Example 6, without any modification, relied solely on their inherent properties, resulting in the lowest thermal resistance.

[0184] Compared to Example 7, Example 2 used a finishing solution containing PCM phase change microcapsules. PCM undergoes a solid-liquid transformation near its phase change temperature (28°C), absorbing or releasing a large amount of heat and actively regulating the microenvironment temperature, thereby significantly improving apparent thermal resistance (i.e., feeling warmer). Example 7 lacked this crucial function, relying solely on fiber grafting, and therefore had lower thermal resistance.

[0185] Compared to Example 8, Example 7, with grafting and no treatment at all, directly demonstrates the effectiveness of the grafting process. Even without post-treatment PCM, the additional material layer introduced by grafting provides better thermal insulation properties than virgin fibers.

[0186] Example 9, as a pure wool system, provides maximum static air content due to its 100% wool content. Meanwhile, the grafted hollow lignin nanospheres further enhance its thermal insulation properties without the structural interference that might result from the incorporation of any other fibers (such as kapok), forming a pure and highly efficient thermal insulation system.

[0187] The higher the breathability, the cooler and more comfortable it is to wear. The key factors affecting breathability are the porosity and the unobstructed flow of the channels within the fabric.

[0188] The difference between Example 2 and Example 3 lies in the blending ratio. Wool fibers are finer and more crimped, resulting in a denser yarn and fabric structure with smaller pores, thus increasing resistance to airflow. The higher the wool content, the more pronounced this densification effect, and consequently, the lower the air permeability.

[0189] In Examples 2, 4, and 5, due to the different grafting targets, grafting partially blocked the pores between fibers. In Example 2, both were grafted, resulting in the most severe pore blockage and the lowest air permeability, though still significantly higher than pure wool. In Example 4, the kapok fibers were coarse, hollow, and stiff, easily forming large pores. Although there was a polymer layer on the surface, it may not be sufficient to completely offset its naturally high air permeability. In Example 5, the wool fibers themselves had a relatively dense structure; grafting nanospheres further reduced the pores, resulting in lower air permeability than in Example 4.

[0190] Example 6: The grafted material occupies the space between fibers, effectively reducing the cross-sectional area of ​​airflow channels, directly leading to a decrease in air permeability. Example 7: No finishing treatment is needed. Finishing solutions (especially waterborne polyurethane and siloxanes) form a thin film on the fabric surface, which is a major obstacle to air permeability. Example 2: Finishing treatment covered this film, resulting in a significant decrease in air permeability. Example 7: Without this film, air permeability is better. Example 8: The fibers, without any grafting or finishing treatment, retain the largest original porosity and the most unobstructed air channels, resulting in the best air permeability. Example 9: 100% wool forms a very tight fabric structure (fine, crimped, and entangled scales), making it extremely difficult for air to pass through. The grafted nanospheres further fill the remaining pores, resulting in the lowest air permeability among all examples.

[0191] Analysis of differences in washability (changes before and after washing)

[0192] The thermal resistance decreased (Examples 2-6): The main reason is that the PCM phase change microcapsules and part of the polymer coating in the finishing agent were detached and lost after multiple washes, which weakened their active heat storage and additional heat insulation functions.

[0193] Increased air permeability (Examples 2-6): This is also because washing removes some of the finishing agent film and grafting material that clog the pores, making the air channels more unobstructed.

[0194] Examples 7 and 9 (thermal resistance stable): Because they were not post-finished, their properties depend solely on substances firmly bonded to the fiber surface via chemical grafting (amide bonds). This chemical bonding is very strong and has excellent wash resistance, resulting in minimal change in properties before and after washing.

[0195] Example 8 (Slightly increased thermal resistance, decreased air permeability): This is a typical phenomenon of wool felting. After washing, the scales of the wool fibers become entangled under mechanical force and heat, resulting in a denser fabric structure. The denser structure traps more air (slightly increased thermal resistance), but also severely blocks airflow channels (decreased air permeability).

[0196] In summary, the solutions in Examples 2 and 3 are the best overall choices for maximizing thermal insulation performance while maintaining adequate air permeability.

[0197] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a warm and breathable blended fiber, characterized in that, Includes the following steps: S1 fiber pretreatment: Soak wool and kapok fibers in an alkaline solution, then wash until neutral, and dry for later use; S2 Wool Grafting: Hollow lignin nanospheres are grafted onto wool through a grafting reaction to obtain grafted wool; S3 Kapok Surface Treatment: After the kapok fibers are activated, a hydrophilic polymer grafting solution is prepared. The activated kapok is immersed in the solution and the hydrophilic polymer segments are grafted onto the kapok through free radical polymerization to obtain grafted kapok. S4 blended fabrication: grafted wool and grafted kapok are opened separately, with grafted wool having fibers ≤20mm in length removed; grafted kapok having fibers ≤15mm in length removed. Grafted wool and grafted kapok are mixed at a mass ratio of 6.5-7.5:2.5-3.5, then combed, spun, and woven to obtain a preliminary blended fabric; S5 finishing: Immerse the initial blended fabric in the finishing solution, then dip and rub twice; then dry. The finishing solution comprises at least the following components by mass percentage: The core material of the phase change microcapsule heat preservation agent is n-octadecane, and the phase change temperature range is 28-32℃.

2. The method for preparing the warm and breathable blended fiber according to claim 1, characterized in that, The method for preparing the hollow lignin nanospheres is as follows: Lignin is dissolved in a good solvent to prepare a solution; while stirring, a poor solvent is added dropwise to the solution to initiate self-assembly; After self-assembly, the good solvent is removed, and then the nanospheres are collected by centrifugation and washed to obtain hollow lignin nanospheres.

3. The method for preparing the warm and breathable blended fiber according to claim 2, characterized in that, The good solvent and the bad solvent are miscible; The concentration of the solution is ≤5mg / mL; the stirring rate when the undesirable solvent is added is ≥500rpm and the dropping rate is ≤2mL / min.

4. The method for preparing the warm and breathable blended fiber according to claim 1, characterized in that, In step S2, wool grafting, the following is included: The wool is added to the dispersion, stirred at a constant temperature to induce a grafting reaction, and then dried after the reaction is complete. The dispersion contains at least the following components by mass percentage: Hollow lignin nanospheres ≥5 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide ≥0.5 N-hydroxysuccinimide ≥0.3 The bath ratio of wool is 1:≥40; the pH of the dispersion is≤5.5; the temperature of constant temperature stirring is≥50℃, and the time is≥3h.

5. The method for preparing the warm and breathable blended fiber according to claim 1, characterized in that, In the S3 kapok surface treatment: Kapok fibers are etched with cellulase before activation; The hydrophilic polymer grafting solution shall include at least the following components by mass percentage: When immersing the activated kapok in the solution, the temperature should be ≥60℃, and stirring should be maintained for at least 2 hours; the bath ratio of the kapok should be 1:≥50. After grafting, wash and dry to obtain grafted kapok.

6. The method for preparing the warm and breathable blended fiber according to claim 1, characterized in that, In the S5 finishing process, the softener is a silicone-based softener; the crosslinking agent is a blocked isocyanate.

7. A treatment agent, characterized in that, It should include at least the following components, calculated as a percentage by weight: Hollow lignin nanospheres ≥5 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide ≥0.5 N-hydroxysuccinimide ≥0.3 The solvent for the treatment agent is water; the preparation method of the hollow lignin nanospheres is as follows: Lignin is dissolved in a good solvent to prepare a solution; while stirring, a poor solvent is added dropwise to the solution to initiate self-assembly; After self-assembly, the good solvent is removed, and then the nanospheres are collected by centrifugation and washed to obtain hollow lignin nanospheres. The good solvent and the bad solvent are miscible.

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