Air-permeable anti-penetrating down function film, preparation method thereof and application in fabric

Abstract

This invention discloses a breathable and down-proof functional membrane, its preparation method, and its application in fabrics. By weight, it comprises the following raw materials: 100 parts of aqueous polyurethane dispersion, 10-15 parts of modified halloysite nanotubes, 5-8 parts of polydopamine-coated nano-zinc oxide, 5-7 parts of ammonium bicarbonate, 2-4 parts of additives, 1-2 parts of thickener, and 0.3-0.8 parts of defoamer. This breathable and down-proof functional membrane uses an aqueous polyurethane dispersion as the matrix, synergistically introducing modified halloysite nanotubes, polydopamine-coated nano-zinc oxide, ammonium bicarbonate pore-forming agent, and quaternary ammonium salt additives to form a breathable and down-proof functional membrane system. Through a three-stage film-forming process, a dual-scale porous structure with micron and nanoscale coexisting is constructed within the membrane. The synergistic effect of the two levels of pores achieves both breathability and down-proof functionality.

Description

Technical Field

[0001] This invention belongs to the field of functional membrane technology, specifically relating to a breathable and down-proof functional membrane, its preparation method, and its application in fabrics. Background Technology

[0002] Down products are widely used in clothing, bedding, and outdoor equipment due to their excellent warmth and lightweight properties. However, down fibers are small in diameter and easily penetrate the fabric structure during use under friction, compression, and other external forces, resulting in down leakage, which not only affects the appearance of the product but also reduces its warmth. Therefore, down-proof performance has become one of the core technical indicators of down product fabrics, and current national standards have clear requirements for the down-proof performance of down garments.

[0003] Currently, the main technical approaches to improving the down-proof performance of fabrics fall into the following categories: First, increasing the warp and weft density of the fabric to reduce the interfacial gaps. However, high-density fabrics have poor breathability and moisture permeability, resulting in a significant decrease in wearing comfort, and the increased weight contradicts the need for lightweighting. Second, applying water-repellent finishing treatments to the fabric (such as waxing or fluorinated finishing agents) utilizes the hydrophobic effect of the fiber surface to prevent down from penetrating. However, long-chain perfluorinated compounds such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are strictly restricted by laws in many countries due to their environmental persistence and bioaccumulation, while short-chain alternatives have insufficient waterproof durability. Third, applying a dense coating to the inside of the fabric can effectively seal the pores. However, continuous dense coatings almost completely block the conduction channels of water vapor, leading to a significant decrease in the fabric's moisture permeability and affecting wearing comfort. There is an inherent performance contradiction between down-proofness and breathability and moisture permeability, making it difficult to achieve both simultaneously.

[0004] Regarding antibacterial properties, down fillings are rich in protein, making them prone to bacterial growth and odor in humid environments, affecting hygiene. Current antibacterial finishing techniques for down products often employ nano-silver, quaternary ammonium salts, or triclosan as post-treatment agents. However, these methods generally suffer from insufficient adhesion between the antibacterial agent and the fabric, poor wash resistance, and a significant decrease in antibacterial effectiveness with repeated use. Furthermore, the continuous release of antibacterial agents has raised concerns about drug resistance and ecotoxicity.

[0005] In the field of functional membrane materials, polyurethane films are widely used in functional coatings for textiles due to their excellent elasticity, adjustable mechanical properties, and flexible film-forming processes. Solvent-based polyurethane was once the mainstream technology, but the use of large amounts of organic solvents in its production process has led to problems such as volatile organic compound emissions and solvent residues. As environmental regulations become increasingly stringent in various countries, waterborne polyurethane dispersions are gradually becoming the alternative.

[0006] However, existing waterborne polyurethane coatings still have technical limitations in terms of balancing moisture permeability and mechanical strength, uniformity of filler dispersion, and precise control of film pore structure. Preparing waterborne polyurethane functional membranes with high moisture permeability, excellent anti-downing properties, and long-lasting antibacterial functions remains a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a breathable and down-proof functional film, its preparation method, and its application in fabrics.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A breathable and down-proof functional membrane, comprising the following raw materials by weight: 100 parts of waterborne polyurethane dispersion, 10-15 parts of modified halloysite nanotubes, 5-8 parts of polydopamine-coated nano zinc oxide, 5-7 parts of ammonium bicarbonate, 2-4 parts of additives, 1-2 parts of thickener, and 0.3-0.8 parts of defoamer.

[0009] Preferably, a breathable and down-proof functional membrane comprises, by weight, the following raw materials: 100 parts of waterborne polyurethane dispersion, 12-15 parts of modified halloysite nanotubes, 6-8 parts of polydopamine-coated nano zinc oxide, 5-6 parts of ammonium bicarbonate, 3-4 parts of additives, 1-1.5 parts of thickener, and 0.5-0.8 parts of defoamer.

[0010] Preferably, the solid content of the aqueous polyurethane urea dispersion is 30-40%, and the particle size is 80-200 nm; the thickener is one or both of hydroxyethyl cellulose or polyurethane associative thickener; the defoamer is an organosilicon defoamer; and the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive.

[0011] Preferably, the method for preparing the modified halloysite nanotubes includes the following steps: S1. Add halloysite nanotubes to hydrochloric acid solution, stir and impregnate, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add acid-treated halloysite nanotubes to sodium hydroxide solution, stir at room temperature, filter, wash until neutral, and dry to obtain activated halloysite nanotubes. S2. Activated halloysite nanotubes are added to deionized water, followed by the addition of hydroxyethylidene diphosphonic acid. The pH is adjusted, the reaction is heated, filtered, washed, dried, and then heat-treated to obtain organic halloysite nanotubes. S3. Add organic halloysite nanotubes to an ethanol aqueous solution, then add γ-glycidyl etheroxypropyltrimethoxysilane, react at a constant temperature, cool, filter, wash, and dry to obtain epoxidized halloysite nanotubes. S4. Add halloysite epoxide to anhydrous ethanol, then add 8-hydroxyquinoline and triethylamine, stir the reaction under inert gas protection, filter, wash and dry to obtain the modified halloysite nanotubes.

[0012] Preferably, in step S1, the hydrochloric acid solution has a mass fraction of 10-15%, the stirring and impregnation temperature is 60-70℃, the time is 2-3 hours, the concentration of the sodium hydroxide solution is 0.3-0.5 mol / L, and the stirring time is 1-2 hours; in step S2, the mass ratio of activated halloysite nanotubes, deionized water, and hydroxyethylidene diphosphonic acid is 100:1000-1500:8-12, the pH is 4-5, the heating reaction temperature is 60-70℃, the time is 15-20 hours, and the heat treatment process is: heating at 120-130℃ for 1.5-2.5 hours under a nitrogen atmosphere.

[0013] In this invention, halloysite nanotubes are first etched with hydrochloric acid. This process aims to dissolve the inner aluminum oxide layer, clear the tubular cavity, expose Al-OH sites, and remove natural impurities such as iron oxides from the cavity, providing a physical channel for the subsequent entry of hydroxyethylidene diphosphonic acid into the inner wall of the cavity. Subsequently, the nanotubes are treated with sodium hydroxide solution at room temperature to activate the Si-OH density on the outer wall and neutralize any acid residue, providing sufficient sites for the reaction in step S3. The concentration of the alkali solution is strictly controlled below 0.5 mol / L to avoid dissolving the Al-OH on the inner wall or damaging the tubular morphology of the halloysite.

[0014] Activated halloysite nanotubes were dispersed in deionized water, and hydroxyethylidene diphosphonic acid (HEDDI) was added. The pH was adjusted to 4-5, and the mixture was stirred and impregnated. This allowed HEDDI to form a dual-anchor chelate coordination with the Al-OH group on the inner wall through the bisphosphonic acid group. This densely introduced hydrophilic phosphonic acid hydroxyl and carbohydroxyl groups into the inner wall of the tube, transforming the inner wall from a weakly hydrophilic state to a superhydrophilic state, thereby constructing a continuous water vapor conduction nanochannel. After the reaction was completed, heat treatment was performed to convert the incompletely condensed coordination adsorption between HEDDI and the aluminum hydroxyl groups on the inner wall into a stable covalent bond. This significantly improved the binding strength of HEDDI on the inner wall, ensuring that the structural stability of the hydrophilic and permeable channel could be maintained even after multiple washes of the functional membrane.

[0015] Preferably, in step S3, the volume ratio of ethanol to water in the ethanol-water solution is 90-95:5-10, the mass ratio of the organic halloysite nanotubes to γ-glycidyl etheroxypropyltrimethoxysilane is 100:7-10, and the isothermal reaction is carried out at a temperature of 70-75°C for 4-6 hours; in step S4, the mass ratio of the epoxidized halloysite nanotubes, 8-hydroxyquinoline, and triethylamine is 100:5-8:6-10, and the stirring reaction is carried out at a temperature of 60-70°C for 5-7 hours.

[0016] In this invention, organo-organic halloysite nanotubes are reacted with γ-glycidyl etheroxypropyltrimethoxysilane. The γ-glycidyl etheroxypropyltrimethoxysilane undergoes a condensation reaction with the Si-OH on the outer wall of halloysite to form a stable Si-O-Si covalent bond, thereby introducing a highly reactive epoxy group on the outer wall of halloysite, which is beneficial to the subsequent reaction.

[0017] Epoxidized halloysite nanotubes were reacted with 8-hydroxyquinoline under triethylamine catalysis. The hydroxyl groups of 8-hydroxyquinoline underwent a ring-opening addition reaction with the epoxy groups on the outer wall, covalently immobilizing 8-hydroxyquinoline on the outer wall of the halloysite nanotubes. This endowed the outer wall with durable, environmentally responsive antibacterial activity. After the reaction, the quinoline nitrogen structure of 8-hydroxyquinoline was retained, still possessing the ability to coordinate with metal ions. In the presence of Cu in sweat... 2+ Zn 2+ When metal ions are present, highly active complexes can be formed in situ. These complexes exert sustained antibacterial effects by disrupting bacterial cell membranes, interfering with intracellular metal ion homeostasis, and inducing reactive oxygen species generation. Furthermore, since 8-hydroxyquinoline is fixed by covalent bonds, there is no problem of dissolution and loss of active components. Therefore, its antibacterial durability is significantly better than that of physical adsorption-type finishing methods.

[0018] Preferably, the preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted at room temperature and in air for 12-24 hours. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

[0019] In this invention, polydopamine (PDA) is used to coat the surface of nano-zinc oxide. On the one hand, the coating of ZnO by the PDA shell can regulate the Zn content. 2+ The release rate is adjusted, changing it from a rapid burst release to a slow, sustained release, thus reducing the release of high-concentration Zn while maintaining sustained antibacterial activity. 2+ On the one hand, PDA has potential toxicity to cells; on the other hand, its surface is rich in catechol groups, which can form hydrogen bonds with urethane and urea bonds in the aqueous polyurethane dispersion matrix, significantly improving the dispersion uniformity of nano-zinc oxide in the polyurethane matrix and inhibiting nanoparticle aggregation, thereby avoiding film-forming defects caused by aggregation. Furthermore, PDA itself also has certain antibacterial activity, interacting with the ZnO... 2+ The sustained-release antibacterial mechanism forms a synergistic effect, further enhancing the overall antibacterial effect of the functional membrane.

[0020] This invention also protects a method for preparing a breathable and down-proof functional film as described above, comprising the following steps: Modified halloysite nanotubes and polydopamine-coated zinc oxide nanotubes were ultrasonically dispersed in deionized water at a power of 200W for 30 minutes to obtain dispersions of each filler. Add the aqueous polyurethane dispersion to a mixing container, then add ammonium bicarbonate aqueous solution, various filler dispersions, additives, thickeners, and defoamers in sequence. After stirring evenly, degas under vacuum at -0.08 MPa for 30 min to obtain the coating liquid. Apply the coating liquid onto the release fabric, controlling the wet film thickness to be 150-250 μm. Then, treat the release fabric carrying the wet film in three stages: the first stage is treated at 45-55℃ for 10-15 min, the second stage is immersed in deionized water for 50-90 s, and the third stage is treated at 80-90℃ for 20-30 min. After cooling, peel it off from the release fabric and cut it to obtain the final product.

[0021] Preferably, the ammonium bicarbonate is added in the form of an aqueous solution of ammonium bicarbonate, the concentration of which is 15-25 wt%; the release fabric is a silicone-treated PET release fabric; and the temperature of the deionized water is maintained at 23-27°C.

[0022] This invention also protects the application of the breathable and down-proof functional film described above in fabrics, wherein the breathable and down-proof functional film is bonded to the fabric layer by hot melt adhesive dot bonding to form a composite down-proof functional fabric; the hot melt adhesive is a low-temperature polyamide hot melt adhesive, the bonding temperature is 110-140℃, the pressure is 0.3-0.5MPa, and the hot melt adhesive dot coverage rate is 15-20%; the composite down-proof functional fabric is used in down jacket fabrics, down duvet covers, down sleeping bag fabrics, or down pillows.

[0023] In this invention, a low-temperature polyamide hot melt adhesive is used to laminate the functional film and the fabric layer in a dotted manner, with the hot melt adhesive dot coverage rate controlled at 15-20%. The dotted bonding method keeps a large area of ​​the functional film in a non-adhesive free state, preserving the moisture and air permeability channels of the functional film and avoiding the problem of a significant decrease in moisture permeability caused by the adhesive layer blocking the pores in the full lamination process; the use of low-temperature polyamide hot melt adhesive (lamination temperature 110-140℃) allows the lamination to be completed below the softening temperature of the polyurethane functional film, preventing the collapse and deformation of the membrane pore structure caused by high temperature.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) The breathable and down-proof functional membrane provided by the present invention uses an aqueous polyurethane dispersion as the matrix and synergistically introduces a breathable and down-proof functional membrane system consisting of modified halloysite nanotubes, polydopamine-coated nano zinc oxide, ammonium bicarbonate pore-forming agent, and quaternary ammonium salt additives. Through a three-stage film formation process, a dual-scale porous structure with micron and nano-scale coexistence is constructed in the membrane. Micron-scale air bubbles are uniformly distributed in the polyurethane matrix, providing macroscopic channels for rapid water vapor conduction, and connecting the gaps between micron-scale pores and nano-scale particles on both sides of the membrane. Within the polyurethane, the effective pore size is much smaller than the diameter of down filaments, forming a physical barrier that prevents down fibers from penetrating. The two levels of pores complement each other in space, working together to achieve a balance between moisture permeability and down-proof barrier properties. Meanwhile, modified halloysite nanotubes and polydopamine-coated nano-zinc oxide respectively endow the membrane with moisture-directing and long-lasting antibacterial functions, while quaternary ammonium salt additives further enhance the down-proof effect on the membrane surface. The overall solution adopts a fully aqueous system, is free of halogens and perfluorinated compounds, and complies with current environmental regulations for textiles.

[0025] (2) The breathable and down-proof functional membrane provided by this invention is subjected to targeted functional modification on the inner and outer walls of halloysite nanotubes through two-step differential activation (hydrochloric acid preferentially etches the inner wall aluminum oxide layer and sodium hydroxide activates the outer wall silanol groups); the inner wall is coordinated and anchored by the bisphosphonic acid groups of hydroxyethylidene diphosphonic acid, and phosphonic acid hydroxyl and carbohydroxyl groups are densely introduced into the inner wall of the tube, giving the inner tube strong hydrophilicity and forming a continuous water vapor conduction channel; the outer wall is grafted with γ-glycidoxypropyltrimethoxysilane and then covalently bonded with 8-hydroxyquinoline through an epoxy ring-opening reaction, giving the outer wall environmentally responsive antibacterial activity. 8-hydroxyquinoline reacts with Cu in sweat 2+ Zn 2+ When metal ions are present, complexes with antibacterial activity can be formed in situ. Unlike sustained-release antibacterial agents, this reduces the risk of drug resistance. The differentiated functional design of the inner and outer walls allows a single filler to have both moisture-permeable guidance and antibacterial functions, avoiding compatibility issues when multiple functional additives are used in combination.

[0026] (3) The breathable and down-proof functional membrane provided by the present invention is a triple antibacterial system composed of modified halloysite nanotube outer wall 8-hydroxyquinoline, polydopamine-coated nano zinc oxide, and quaternary ammonium salt additives. The three antibacterial mechanisms have different focuses in terms of action site, action mode and action time. The quaternary ammonium salt additives act on the membrane surface and kill the bacteria that come into contact with it immediately; the polydopamine-coated nano zinc oxide is activated by Zn 2+ Controlled release provides long-lasting antibacterial effects; the polydopamine coating effectively inhibits Zn. 2+The burst release of the drug prolongs the duration of antibacterial action; 8-hydroxyquinoline is covalently fixed to the outer wall of halloysite nanotubes and activated in a specific ionic environment, supplementing the ability to inhibit bacteria under specific conditions; the three mechanisms of action are complementary and have a broad coverage, which can effectively reduce the problem of declining antibacterial effect caused by concentration decay or drug resistance development under a single antibacterial mechanism.

[0027] (4) The breathable and down-proof functional membrane provided by the present invention adopts a three-stage film formation process. In the first stage, the temperature is controlled near the decomposition initiation temperature of ammonium bicarbonate, so that it is partially decomposed and a primary pore skeleton is pre-formed in the wet membrane. In the second stage, it is immersed in deionized water, and the decomposition products of ammonium bicarbonate in the membrane rapidly diffuse and dissolve into the deionized water, resulting in a sharp drop in the ionic strength in the membrane. The colloidal stability of the waterborne polyurethane particles is destroyed, and the particles are aggregated and solidified. Nanoscale particle gaps are retained inside the polyurethane solid partition with micron-sized bubble pores, which together with the micron-sized pores form a dual-scale multi-layer structure. The three-stage high-temperature treatment drives the complete evaporation of residual moisture, fully integrates the polyurethane particle interfaces, and eliminates internal stress through segment thermal relaxation and hydrogen bond network recombination, achieving a dense and permanent fixation of the membrane microstructure. At the same time, it promotes the interfacial reaction between the surface active groups of modified halloysite nanotubes and the polyurethane matrix, improving the mechanical stability and water wash resistance of the functional membrane. The three-stage process has a clear function and independently controllable parameters in each stage. Compared with the single foaming process, it adds a nanoscale anti-down leakage barrier, thus achieving a better balance between moisture permeability and anti-down leakage barrier properties. Detailed Implementation

[0028] 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.

[0029] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0030] In some embodiments of the present invention, the aqueous polyurethane dispersion is designated as Covestro Impranil® DLN-SD; the halloysite nanotubes have an outer diameter of 50-100 nm, an inner diameter of 15-25 nm, and a tube length of 0.5-2 μm; the long-chain alkyl quaternary ammonium salt cationic functional additive is designated as Clariant Praepagen® WB, with distearate dimethyl ammonium chloride as its main component; the nano zinc oxide has a particle size of 50-80 nm; and the silicone defoamer is a silicone polyether defoamer. Example 1

[0031] A breathable and down-proof functional membrane, comprising the following raw materials by weight: The mixture contains 100 parts of waterborne polyurethane dispersion, 13 parts of modified halloysite nanotubes, 7 parts of polydopamine-coated nano zinc oxide, 6 parts of ammonium bicarbonate, 3 parts of additives, 1.5 parts of thickener, and 0.6 parts of defoamer.

[0032] The thickener is hydroxyethyl cellulose; the defoamer is an organosilicon defoamer; the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive. The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add 100g halloysite nanotubes to 1L of 13% hydrochloric acid solution, stir and soak at 65℃ for 2.5h, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add 100g of acid-treated halloysite nanotubes to 1L of 0.4mol / L sodium hydroxide solution, stir at room temperature for 1.5h, filter, wash until neutral, and dry to obtain activated halloysite nanotubes; S2. Add 100g of activated halloysite nanotubes to 1300g of deionized water, then add 10g of hydroxyethylidene diphosphonic acid, adjust the pH to 4.5, react at 65℃ for 18h, filter, wash, dry, and heat-treat at 125℃ for 2h under nitrogen atmosphere to obtain organic halloysite nanotubes. S3. Add 100g of organic halloysite nanotubes to 1L of ethanol aqueous solution (ethanol to water volume ratio of 90:10), then add 9g of γ-glycidoxypropyltrimethoxysilane, and react at a constant temperature of 75℃ for 5h. After cooling, filter, wash and dry to obtain epoxidized halloysite nanotubes. S4. Add 100g of halloysite epoxide to 1L of anhydrous ethanol, then add 7g of 8-hydroxyquinoline and 8g of triethylamine. Stir and react at 65°C for 6h under inert gas protection. Filter, wash and dry to obtain the modified halloysite nanotubes.

[0033] The preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted for 18 hours at room temperature and in air atmosphere. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

[0034] A method for preparing a breathable and down-proof functional film includes the following steps: Weigh the raw materials according to the formula, and ultrasonically disperse the modified halloysite nanotubes and polydopamine-coated nano zinc oxide in 10 times their weight of deionized water. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain the dispersion of each filler. Aqueous polyurethane dispersion was added to a mixing container, followed by ammonium bicarbonate aqueous solution (20wt%), various filler dispersions, additives, thickeners, and defoamers. After stirring until homogeneous, the mixture was vacuum degassed at -0.08MPa for 30 minutes to obtain a coating solution. The coating solution was then coated onto silicone-treated PET release fabric, with the wet film thickness controlled at 150-250μm. The release fabric carrying the wet film was then subjected to three stages of treatment: the first stage was treated at 50℃ for 15 minutes, the second stage was immersed in deionized water at 25℃ for 70 seconds, and the third stage was treated at 85℃ for 25 minutes. After cooling, the film was peeled off from the release fabric and cut to obtain the final product. Example 2

[0035] A breathable and down-proof functional membrane, comprising the following raw materials by weight: 100 parts of waterborne polyurethane dispersion, 10 parts of modified halloysite nanotubes, 5 parts of polydopamine-coated nano zinc oxide, 5 parts of ammonium bicarbonate, 2 parts of additives, 1 part of thickener, and 0.3 parts of defoamer.

[0036] The thickener is a polyurethane associative thickener; the defoamer is an organosilicon defoamer; the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive. The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add 100g halloysite nanotubes to 1L of 10% hydrochloric acid solution, stir and soak at 60℃ for 3h, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add 100g of acid-treated halloysite nanotubes to 1L of 0.3mol / L sodium hydroxide solution, stir at room temperature for 2h, filter, wash until neutral, and dry to obtain activated halloysite nanotubes; S2. Add 100g of activated halloysite nanotubes to 1000g of deionized water, then add 8g of hydroxyethylidene diphosphonic acid, adjust the pH to 4, react at 60℃ for 20h, filter, wash, dry, and heat-treat at 120℃ for 2.5h under nitrogen atmosphere to obtain organic halloysite nanotubes. S3. Add 100g of organic halloysite nanotubes to 1L of ethanol aqueous solution (ethanol to water volume ratio of 95:5), then add 7g of γ-glycidoxypropyltrimethoxysilane, and react at 70℃ for 6h. After cooling, filter, wash and dry to obtain epoxidized halloysite nanotubes. S4. Add 100g of halloysite epoxide to 1L of anhydrous ethanol, then add 5g of 8-hydroxyquinoline and 6g of triethylamine. Stir and react at 60°C for 7h under inert gas protection. Filter, wash and dry to obtain the modified halloysite nanotubes.

[0037] The preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted for 12 hours at room temperature and in air atmosphere. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

[0038] A method for preparing a breathable and down-proof functional film includes the following steps: Weigh the raw materials according to the formula, and ultrasonically disperse the modified halloysite nanotubes and polydopamine-coated nano zinc oxide in 8 times their weight of deionized water. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain the dispersion of each filler. Aqueous polyurethane dispersion was added to a mixing container, followed by ammonium bicarbonate aqueous solution (15wt%), various filler dispersions, additives, thickeners, and defoamers. After stirring until homogeneous, the mixture was vacuum degassed at -0.08MPa for 30 minutes to obtain a coating solution. The coating solution was then coated onto silicone-treated PET release fabric, with the wet film thickness controlled at 150-250μm. The release fabric carrying the wet film was then subjected to three stages of treatment: the first stage was treated at 45℃ for 15 minutes, the second stage was immersed in deionized water at 23℃ for 90 seconds, and the third stage was treated at 80℃ for 30 minutes. After cooling, the film was peeled off from the release fabric and cut to obtain the final product. Example 3

[0039] A breathable and down-proof functional membrane, comprising the following raw materials by weight: 100 parts of waterborne polyurethane dispersion, 15 parts of modified halloysite nanotubes, 8 parts of polydopamine-coated nano zinc oxide, 7 parts of ammonium bicarbonate, 4 parts of additives, 2 parts of thickener, and 0.8 parts of defoamer.

[0040] The thickener is hydroxyethyl cellulose; the defoamer is an organosilicon defoamer; the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive. The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add 100g halloysite nanotubes to 1L of 15% hydrochloric acid solution, stir and soak at 70℃ for 2h, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add 100g of acid-treated halloysite nanotubes to 1L of 0.5mol / L sodium hydroxide solution, stir at room temperature for 1h, filter, wash until neutral, and dry to obtain activated halloysite nanotubes; S2. Add 100g of activated halloysite nanotubes to 1500g of deionized water, then add 12g of hydroxyethylidene diphosphonic acid, adjust the pH to 5, react at 70℃ for 15h, filter, wash, dry, and heat treat at 130℃ for 1.5h under nitrogen atmosphere to obtain organic halloysite nanotubes. S3. Add 100g of organic halloysite nanotubes to 1L of ethanol aqueous solution (ethanol to water volume ratio of 95:5), then add 10g of γ-glycidyl etheroxypropyltrimethoxysilane, react at 75℃ for 4h, cool, filter, wash and dry to obtain epoxidized halloysite nanotubes. S4. Add 100g of halloysite epoxide to 1L of anhydrous ethanol, then add 8g of 8-hydroxyquinoline and 10g of triethylamine. Stir and react at 70°C for 5h under inert gas protection. Filter, wash and dry to obtain the modified halloysite nanotubes.

[0041] The preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted at room temperature and in air for 24 hours. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

[0042] A method for preparing a breathable and down-proof functional film includes the following steps: Weigh the raw materials according to the formula, and ultrasonically disperse the modified halloysite nanotubes and polydopamine-coated nano zinc oxide in 12 times their weight of deionized water. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain the dispersion of each filler. Aqueous polyurethane dispersion was added to a mixing container, followed by ammonium bicarbonate aqueous solution (25wt%), various filler dispersions, additives, thickeners, and defoamers. After stirring until homogeneous, the mixture was vacuum degassed at -0.08MPa for 30 minutes to obtain a coating solution. The coating solution was then coated onto silicone-treated PET release fabric, with the wet film thickness controlled at 150-250μm. The release fabric carrying the wet film was then subjected to three stages of treatment: the first stage was treated at 55℃ for 10 minutes, the second stage was immersed in deionized water at 27℃ for 50 seconds, and the third stage was treated at 90℃ for 20 minutes. After cooling, the film was peeled off from the release fabric and cut to obtain the final product. Comparative Example 1

[0043] A breathable and down-proof functional membrane, comprising the following raw materials by weight: The mixture contains 100 parts of waterborne polyurethane dispersion, 13 parts of modified halloysite nanotubes, 7 parts of polydopamine-coated nano zinc oxide, 6 parts of ammonium bicarbonate, 3 parts of additives, 1.5 parts of thickener, and 0.6 parts of defoamer.

[0044] The thickener is hydroxyethyl cellulose; the defoamer is an organosilicon defoamer; the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive. The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add 100g halloysite nanotubes to 1L of 13% hydrochloric acid solution, stir and soak at 65℃ for 2.5h, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add 100g of acid-treated halloysite nanotubes to 1L of 0.4mol / L sodium hydroxide solution, stir at room temperature for 1.5h, filter, wash until neutral, and dry to obtain activated halloysite nanotubes; S2. Add 100g of activated halloysite nanotubes to 1300g of deionized water, then add 10g of hydroxyethylidene diphosphonic acid, adjust the pH to 4.5, react at 65℃ for 18h, filter, wash, dry, and heat treat at 125℃ for 2h under nitrogen atmosphere to obtain the modified halloysite nanotubes.

[0045] The preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted for 18 hours at room temperature and in air atmosphere. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

[0046] A method for preparing a breathable and down-proof functional film includes the following steps: Weigh the raw materials according to the formula, and ultrasonically disperse the modified halloysite nanotubes and polydopamine-coated nano zinc oxide in 10 times their weight of deionized water. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain the dispersion of each filler. Aqueous polyurethane dispersion was added to a mixing container, followed by ammonium bicarbonate aqueous solution (20wt%), various filler dispersions, additives, thickeners, and defoamers. After stirring until homogeneous, the mixture was vacuum degassed at -0.08MPa for 30 minutes to obtain a coating solution. The coating solution was then coated onto silicone-treated PET release fabric, with the wet film thickness controlled at 150-250μm. The release fabric carrying the wet film was then subjected to three stages of treatment: the first stage was treated at 50℃ for 15 minutes, the second stage was immersed in deionized water at 25℃ for 70 seconds, and the third stage was treated at 85℃ for 25 minutes. After cooling, the film was peeled off from the release fabric and cut to obtain the final product.

[0047] Compared with Example 1, the modified halloysite nanotubes in this comparative example did not undergo silane modification and the introduction of 8-hydroxyquinoline, i.e., steps S3 and S4 were omitted. Comparative Example 2

[0048] A breathable and down-proof functional membrane, comprising the following raw materials by weight: The mixture contains 100 parts of waterborne polyurethane dispersion, 13 parts of modified halloysite nanotubes, 7 parts of polydopamine-coated nano zinc oxide, 6 parts of ammonium bicarbonate, 3 parts of additives, 1.5 parts of thickener, and 0.6 parts of defoamer.

[0049] The thickener is hydroxyethyl cellulose; the defoamer is an organosilicon defoamer; the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive. The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add 100g halloysite nanotubes to 1L of ethanol aqueous solution (ethanol to water volume ratio of 90:10), then add 9g of γ-glycidoxypropyltrimethoxysilane, and react at a constant temperature of 75℃ for 5h. After cooling, filter, wash and dry to obtain epoxidized halloysite nanotubes. S2. Add 100g of halloysite epoxide to 1L of anhydrous ethanol, then add 7g of 8-hydroxyquinoline and 8g of triethylamine. Stir and react at 65°C for 6h under inert gas protection. Filter, wash and dry to obtain the modified halloysite nanotubes.

[0050] The preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted for 18 hours at room temperature and in air atmosphere. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

[0051] A method for preparing a breathable and down-proof functional film includes the following steps: Weigh the raw materials according to the formula, and ultrasonically disperse the modified halloysite nanotubes and polydopamine-coated nano zinc oxide in 10 times their weight of deionized water. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain the dispersion of each filler. Aqueous polyurethane dispersion was added to a mixing container, followed by ammonium bicarbonate aqueous solution (20wt%), various filler dispersions, additives, thickeners, and defoamers. After stirring until homogeneous, the mixture was vacuum degassed at -0.08MPa for 30 minutes to obtain a coating solution. The coating solution was then coated onto silicone-treated PET release fabric, with the wet film thickness controlled at 150-250μm. The release fabric carrying the wet film was then subjected to three stages of treatment: the first stage was treated at 50℃ for 15 minutes, the second stage was immersed in deionized water at 25℃ for 70 seconds, and the third stage was treated at 85℃ for 25 minutes. After cooling, the film was peeled off from the release fabric and cut to obtain the final product.

[0052] Compared with Example 1, the modified halloysite nanotubes in this comparative example were not activated and modified, and hydroxyethylidene diphosphonic acid was not introduced, i.e., steps S1 and S2 were omitted. Comparative Example 3

[0053] A breathable and down-proof functional membrane, comprising the following raw materials by weight: The mixture contains 100 parts of waterborne polyurethane dispersion, 13 parts of modified halloysite nanotubes, 7 parts of polydopamine-coated nano zinc oxide, 6 parts of ammonium bicarbonate, 3 parts of additives, 1.5 parts of thickener, and 0.6 parts of defoamer.

[0054] The thickener is hydroxyethyl cellulose; the defoamer is an organosilicon defoamer; the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive. The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add 100g halloysite nanotubes to 1L of 13% hydrochloric acid solution, stir and soak at 65℃ for 2.5h, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add 100g of acid-treated halloysite nanotubes to 1L of 0.4mol / L sodium hydroxide solution, stir at room temperature for 1.5h, filter, wash until neutral, and dry to obtain activated halloysite nanotubes; S2. Add 100g of activated halloysite nanotubes to 1300g of deionized water, then add 10g of hydroxyethylidene diphosphonic acid, adjust the pH to 4.5, react at 65℃ for 18h, filter, wash, dry, and heat-treat at 125℃ for 2h under nitrogen atmosphere to obtain organic halloysite nanotubes. S3. Add 100g of organic halloysite nanotubes to 1L of ethanol aqueous solution (ethanol to water volume ratio of 90:10), then add 9g of γ-glycidoxypropyltrimethoxysilane, and react at a constant temperature of 75℃ for 5h. After cooling, filter, wash and dry to obtain epoxidized halloysite nanotubes. S4. Add 100g of halloysite epoxide to 1L of anhydrous ethanol, then add 7g of 8-hydroxyquinoline and 8g of triethylamine. Stir and react at 65°C for 6h under inert gas protection. Filter, wash and dry to obtain the modified halloysite nanotubes.

[0055] The preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted for 18 hours at room temperature and in air atmosphere. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

[0056] A method for preparing a breathable and down-proof functional film includes the following steps: Weigh the raw materials according to the formula, and ultrasonically disperse the modified halloysite nanotubes and polydopamine-coated nano zinc oxide in 10 times their weight of deionized water. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain the dispersion of each filler. Aqueous polyurethane dispersion was added to a mixing container, followed by ammonium bicarbonate aqueous solution (20wt%), various filler dispersions, additives, thickeners, and defoamers. After stirring until homogeneous, the mixture was vacuum degassed at -0.08MPa for 30 minutes to obtain a coating liquid. The coating liquid was then coated onto silicone-treated PET release fabric, with the wet film thickness controlled at 150-250μm. The release fabric carrying the wet film was then subjected to two stages of treatment: the first stage was treated at 50℃ for 15 minutes, and the second stage was treated at 85℃ for 25 minutes. After cooling, the film was peeled off from the release fabric and cut to obtain the final product.

[0057] Compared with Example 1, this comparative example did not involve a second stage of immersion in deionized water at 25°C during the preparation of the breathable and down-proof polyurethane functional membrane. Comparative Example 4

[0058] A breathable and down-proof functional membrane, comprising the following raw materials by weight: 100 parts of waterborne polyurethane dispersion, 13 parts of modified halloysite nanotubes, 6 parts of ammonium bicarbonate, 3 parts of additives, 1.5 parts of thickener, and 0.6 parts of defoamer.

[0059] The thickener is hydroxyethyl cellulose; the defoamer is an organosilicon defoamer; the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive. The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add 100g halloysite nanotubes to 1L of 13% hydrochloric acid solution, stir and soak at 65℃ for 2.5h, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add 100g of acid-treated halloysite nanotubes to 1L of 0.4mol / L sodium hydroxide solution, stir at room temperature for 1.5h, filter, wash until neutral, and dry to obtain activated halloysite nanotubes; S2. Add 100g of activated halloysite nanotubes to 1300g of deionized water, then add 10g of hydroxyethylidene diphosphonic acid, adjust the pH to 4.5, react at 65℃ for 18h, filter, wash, dry, and heat-treat at 125℃ for 2h under nitrogen atmosphere to obtain organic halloysite nanotubes. S3. Add 100g of organic halloysite nanotubes to 1L of ethanol aqueous solution (ethanol to water volume ratio of 90:10), then add 9g of γ-glycidoxypropyltrimethoxysilane, and react at a constant temperature of 75℃ for 5h. After cooling, filter, wash and dry to obtain epoxidized halloysite nanotubes. S4. Add 100g of halloysite epoxide to 1L of anhydrous ethanol, then add 7g of 8-hydroxyquinoline and 8g of triethylamine. Stir and react at 65°C for 6h under inert gas protection. Filter, wash and dry to obtain the modified halloysite nanotubes.

[0060] A method for preparing a breathable and down-proof functional film includes the following steps: Weigh the raw materials according to the formula, and ultrasonically disperse the modified halloysite nanotubes in 10 times their weight of deionized water. The ultrasonic power is 200W and the ultrasonic time is 30min to obtain the dispersion of each filler. Aqueous polyurethane dispersion was added to a mixing container, followed by ammonium bicarbonate aqueous solution (20wt%), various filler dispersions, additives, thickeners, and defoamers. After stirring until homogeneous, the mixture was vacuum degassed at -0.08MPa for 30 minutes to obtain a coating solution. The coating solution was then coated onto silicone-treated PET release fabric, with the wet film thickness controlled at 150-250μm. The release fabric carrying the wet film was then subjected to three stages of treatment: the first stage was treated at 50℃ for 15 minutes, the second stage was immersed in deionized water at 25℃ for 70 seconds, and the third stage was treated at 85℃ for 25 minutes. After cooling, the film was peeled off from the release fabric and cut to obtain the final product.

[0061] Compared to Example 1, this comparative example did not include polydopamine-coated nano-zinc oxide.

[0062] The breathable and down-proof functional films prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The tensile strength and elongation at break were tested according to GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets". The functional films were cut into dumbbell-shaped specimens (Type V) with a gauge length of 25 mm and a width of 4 mm, and the tensile rate was 200 mm / min. The moisture permeability was tested according to GB / T 12704.1-2009 "Textiles - Test methods for moisture permeability of fabrics - Part 1: Moisture absorption method". The functional films were cut into 70 mm diameter circular pieces, sealed in a moisture-permeable cup containing desiccant (anhydrous calcium chloride), and placed in a constant temperature and humidity chamber at (38±2)℃ and (90±2)% relative humidity. After standing for 1 hour, the films were weighed, and the moisture permeability was calculated. The antibacterial properties were tested according to GB / T The test was conducted according to 20944.3-2008 "Evaluation of Antimicrobial Properties of Textiles - Part 3: Shaking Method". The test strains were Staphylococcus aureus and Escherichia coli. 0.75 g of the functional membrane sample was taken and 70 mL of phosphate buffer and bacterial suspension (2.0 × 10⁻⁶) was added. 5 (CFU / mL); placed in a (24±1)℃ shaking incubator and shaken at 200r / min for 18h. The antibacterial rate was calculated, and the test results are shown in Table 1 below.

[0063] Table 1

[0064] As can be seen from Table 1 above, the breathable and lint-proof functional membrane prepared by this method has excellent comprehensive performance. The tensile strength and elongation at break of Examples 1-3 are relatively high, indicating that the functional membrane maintains good mechanical properties while introducing a hierarchical pore structure; the moisture permeability reaches 8490 g / m³. 2 • After more than 24 hours, the synergistic moisture permeability effect of the hierarchical pore structure and the hydrophilic channels of hydroxyethylidene diphosphonic acid was fully demonstrated. The inhibition rate of Staphylococcus aureus and Escherichia coli both reached over 99%, proving that the triple antibacterial system composed of the 8-hydroxyquinoline functionalized outer wall, polydopamine-coated nano-zinc oxide, and quaternary ammonium salt adjuvant has excellent broad-spectrum antibacterial properties. Compared with the comparative examples, omitting the halloysite nanotube outer wall modification (Comparative Example 1) resulted in a simultaneous decrease in mechanical properties and antibacterial rate; omitting the inner wall hydroxyethylidene diphosphonic acid modification (Comparative Example 2) reduced moisture permeability; Comparative Example 3 showed some improvement in mechanical properties but a significant decrease in moisture permeability; and removing the polydopamine-coated nano-zinc oxide (Comparative Example 4) resulted in a significant decrease in antibacterial rate. The above comparative results jointly verify the indispensability of each technical element of this scheme to the mechanical properties, moisture permeability, and antibacterial properties of the functional membrane, as well as their synergistic effect.

[0065] The breathable and down-proof functional films prepared in Examples 1 and 1-4 were applied to fabrics. The breathable and down-proof functional films were laminated between two layers of standard test fabric (70D×70D nylon plain weave fabric) using a low-temperature polyamide hot melt adhesive dot bonding method. The bonding temperature was 120℃, the pressure was 0.4MPa, and the hot melt adhesive dot coverage was 15%, forming a three-layer composite down-proof functional fabric. A 30cm×30cm sample was cut and filled with 20g of 90% white duck down (down content ≥90%). The down-proof performance was tested according to GB / T 12705.2-2024 "Textiles - Test Methods for Down-proofness of Fabrics - Part 2: Rotating Box Method". The sample was placed in a rotating box and rotated at 60r / min for 30min at a temperature of 20±2℃ and a relative humidity of 65±5%. The number of down feathers that escaped was counted. The wash resistance was tested according to GB / T... The test was conducted according to 8629-2017 "Home Washing and Drying Procedures for Textile Testing". After 50 washes, the retention rates of down-proofing and Staphylococcus aureus inhibition were measured. The test results are shown in Table 2.

[0066] Table 2

[0067] As can be seen from Table 2, the breathable and down-proof polyurethane functional film composite fabric prepared by this scheme has excellent comprehensive performance and durability. In terms of down-proof performance, the initial down-proof number of Example 1 was only 3 strands / wash, while that of Comparative Example 3 was as high as 25 strands / wash. After 50 washes, it further deteriorated to 41 strands / wash, which is in stark contrast to Example 1, which still maintained 5 strands / wash after washing. This proves that the pore structure of this scheme is the core of achieving durable down-proof performance. In terms of antibacterial wash resistance, the Staphylococcus aureus inhibition retention rate of Example 1 after 50 washes was as high as 95.7%, which is better than that of Comparative Example 1 and Comparative Example 4. This shows that the synergistic effect of 8-hydroxyquinoline chelate grafting and polydopamine-coated nano zinc oxide not only endows the functional film with excellent initial antibacterial properties, but also significantly improves the wash resistance of the antibacterial function.

[0068] The above description is a further detailed explanation of the present invention in conjunction with specific implementation examples. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

[0069] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A breathable and down-proof functional film, characterized in that, By weight, it includes the following ingredients: 100 parts of waterborne polyurethane dispersion, 10-15 parts of modified halloysite nanotubes, 5-8 parts of polydopamine-coated nano zinc oxide, 5-7 parts of ammonium bicarbonate, 2-4 parts of additives, 1-2 parts of thickener, and 0.3-0.8 parts of defoamer; The method for preparing the modified halloysite nanotubes includes the following steps: S1. Add halloysite nanotubes to hydrochloric acid solution, stir and impregnate, filter, wash until neutral, and dry to obtain acid-treated halloysite nanotubes; then add acid-treated halloysite nanotubes to sodium hydroxide solution, stir at room temperature, filter, wash until neutral, and dry to obtain activated halloysite nanotubes. S2. Activated halloysite nanotubes are added to deionized water, followed by the addition of hydroxyethylidene diphosphonic acid. The pH is adjusted, the reaction is heated, filtered, washed, dried, and then heat-treated to obtain organic halloysite nanotubes. S3. Add organic halloysite nanotubes to an ethanol aqueous solution, then add γ-glycidyl etheroxypropyltrimethoxysilane, react at a constant temperature, cool, filter, wash, and dry to obtain epoxidized halloysite nanotubes. S4. Add halloysite epoxide to anhydrous ethanol, then add 8-hydroxyquinoline and triethylamine, stir the reaction under inert gas protection, filter, wash and dry to obtain the modified halloysite nanotubes.

2. The breathable and down-proof functional membrane according to claim 1, characterized in that, By weight, it includes the following raw materials: 100 parts of waterborne polyurethane dispersion, 12-15 parts of modified halloysite nanotubes, 6-8 parts of polydopamine-coated nano zinc oxide, 5-6 parts of ammonium bicarbonate, 3-4 parts of additives, 1-1.5 parts of thickener, and 0.5-0.8 parts of defoamer.

3. The breathable and down-proof functional membrane according to claim 1, characterized in that, The waterborne polyurethane urea dispersion has a solid content of 30-40% and a particle size of 80-200 nm; the thickener is one or both of hydroxyethyl cellulose or polyurethane associative thickeners; the defoamer is an organosilicon defoamer; and the additive is a long-chain alkyl quaternary ammonium salt cationic functional additive.

4. The breathable and down-proof functional membrane according to claim 1, characterized in that, In step S1, the hydrochloric acid solution has a mass fraction of 10-15%, the stirring and impregnation temperature is 60-70℃, and the time is 2-3 hours. The concentration of the sodium hydroxide solution is 0.3-0.5 mol / L, and the stirring time is 1-2 hours. In step S2, the mass ratio of activated halloysite nanotubes, deionized water, and hydroxyethylidene diphosphonic acid is 100:1000-1500:8-12. The pH is 4-5. The heating reaction temperature is 60-70℃, and the time is 15-20 hours. The heat treatment process is as follows: heating at 120-130℃ for 1.5-2.5 hours under a nitrogen atmosphere.

5. The breathable and down-proof functional membrane according to claim 1, characterized in that, In step S3, the volume ratio of ethanol to water in the aqueous ethanol solution is 90-95:5-10, the mass ratio of the organic halloysite nanotubes to γ-glycidoxypropyltrimethoxysilane is 100:7-10, and the isothermal reaction temperature is 70-75℃ for 4-6 hours. In step S4, the mass ratio of epoxidized halloysite nanotubes, 8-hydroxyquinoline, and triethylamine is 100:5-8:6-10, and the stirring reaction temperature is 60-70℃ for 5-7 hours.

6. The breathable and down-proof functional membrane according to claim 1, characterized in that, The preparation method of the polydopamine-coated nano zinc oxide is as follows: Nano zinc oxide was ultrasonically dispersed in a Tris-HCl buffer solution with a pH of 8.5, and dopamine hydrochloride was added. The mixture was stirred and reacted at room temperature and in air for 12-24 hours. After centrifugation, washing with deionized water, and vacuum drying at 60°C, the product was obtained.

7. A method for preparing a breathable and down-proof functional film as described in any one of claims 1-6, characterized in that, Includes the following steps: Modified halloysite nanotubes and polydopamine-coated zinc oxide nanotubes were ultrasonically dispersed in deionized water at a power of 200W for 30 minutes to obtain dispersions of each filler. Add the aqueous polyurethane dispersion to a mixing container, then add ammonium bicarbonate aqueous solution, various filler dispersions, additives, thickeners, and defoamers in sequence. After stirring evenly, degas under vacuum at -0.08 MPa for 30 min to obtain the coating liquid. Apply the coating liquid onto the release fabric, controlling the wet film thickness to be 150-250 μm. Then, treat the release fabric carrying the wet film in three stages: the first stage is treated at 45-55℃ for 10-15 min, the second stage is immersed in deionized water for 50-90 s, and the third stage is treated at 80-90℃ for 20-30 min. After cooling, peel it off from the release fabric and cut it to obtain the final product.

8. The preparation method according to claim 7, characterized in that, The ammonium bicarbonate is added in the form of an aqueous solution of ammonium bicarbonate, with a concentration of 15-25 wt%; the release fabric is a silicone-treated PET release fabric; and the temperature of the deionized water is maintained at 23-27°C.

9. The application of a breathable and down-proof functional film as described in any one of claims 1-6 in a fabric, characterized in that, The breathable and down-proof functional membrane is bonded to the fabric layer using a hot melt adhesive dot bonding method to form a composite down-proof functional fabric. The hot melt adhesive is a low-temperature polyamide hot melt adhesive with a bonding temperature of 110-140℃, a pressure of 0.3-0.5MPa, and a hot melt adhesive dot coverage rate of 15-20%. The composite down-proof functional fabric is used for down jacket fabrics, down duvet covers, down sleeping bag fabrics, or down pillows.

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