A waterproof and breathable composite fabric and a preparation method thereof

Abstract

This invention discloses a waterproof and breathable composite fabric and its preparation method, belonging to the field of textile technology. It solves the problem that waterproof and breathable composite fabrics using polyester-based polyurethane adhesives undergo hydrolytic aging during long-term high-temperature, high-humidity, and high-pressure storage. Initial symptoms are often subtle and easily misdiagnosed during testing, leading to sudden delamination and tearing failure due to a sharp drop in interfacial strength upon use, resulting in irreversible damage and rendering the fabric unusable. This invention addresses these issues by eliminating the root cause of ester bond hydrolysis from a materials chemistry perspective, blocking the self-catalytic acceleration loop in the degradation pathway, preventing structural weakening caused by long-term compression in stress distribution, ensuring the fabric can withstand mechanical loads after aging through interfacial bonding, and providing early visual warning intervention for failure identification. This transforms the hydrolytic reaction from a gradual, unpredictable failure into a slow, visible, predictable, and controllable aging process throughout its entire lifecycle, thereby avoiding the risk of sudden and irreparable fabric collapse at critical moments.

Description

Technical Field

[0001] This invention relates to the field of textile technology, and in particular to a waterproof and breathable composite fabric and its preparation method. Background Technology

[0002] Waterproof and breathable composite fabrics are high-tech textiles that combine waterproofing and breathability. They achieve their special effects through multi-layered material composites, primarily consisting of a high-polymer functional membrane, an outer protective fabric, and an inner skin-friendly fabric. Commonly used functional carriers include PTFE microporous membranes, TPU hydrophilic membranes, or nanofiber membranes. Utilizing microporous filtration or molecular hydrophilic diffusion principles, they prevent external liquid water from penetrating while simultaneously releasing sweat, balancing protection and dryness. The outer layer often uses durable fibers such as polyester and nylon, with water-repellent finishing to enhance surface moisture resistance. The inner layer uses a soft, skin-friendly material to improve fit. All layers are bonded together with a specialized polyurethane adhesive and anti-aging and antibacterial additives to optimize performance. Widely used in outdoor apparel, medical protective gear, and special workwear, these fabrics combine durability and functionality, making them suitable for various complex environments.

[0003] Waterproof and breathable composite fabrics using polyester-type polyurethane adhesives, such as military reserve clothing, emergency disaster relief protective clothing, and outdoor spare jackets, are often stored in high-temperature, high-humidity, and poorly ventilated environments for more than six months, and are often stacked under pressure or vacuum-compressed.

[0004] During this process, the ester bonds in the polyester-based polyurethane adhesive undergo hydrolysis, progressing gradually at the chemical level through autocatalysis. Initially, this manifests only as signs that are not easily detected by a cursory visual inspection, such as a sticky adhesive layer and a slight odor. Furthermore, in the early to mid-stages of hydrolysis, conventional static water pressure tests may still show a "pass" result because the interfacial bonding strength has not yet fallen below the test threshold, thus giving the illusion of perfect functionality. Simultaneously, the hydrolysis process, combined with compression deformation, causes the adhesive layer to creep and flow under sustained high temperatures, altering its thickness distribution and interfacial morphology. This gradual aging leads to a continuous decrease in adhesive cohesion and film self-adhesion during the garment's storage period. If the body is also made of polyester, it will also undergo hydrolysis and embrittlement. When the user takes out the equipment after several months or years and applies mechanical load for the first time, whether it is the natural bending and limb stretching during the first wear or the mechanical agitation during the first wash, the severely weakened interface cannot withstand the peeling force due to the stress concentration on the residual adhesive points. As a result, large-area interface delamination and membrane penetration tearing occur in a very short time. Ultimately, the waterproof and breathable function suddenly collapses when the equipment needs to function. Moreover, since hydrolysis is an irreversible chemical chain breakage, any subsequent washing, water-repellent treatment or local repair cannot restore the interface bonding strength, and the entire garment can only be scrapped.

[0005] Therefore, a waterproof and breathable composite fabric and its preparation method are proposed to solve or alleviate the above problems. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a waterproof and breathable composite fabric and its preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A waterproof and breathable composite fabric includes an outer fabric, an inner fabric, a film layer between the two, and an adhesive layer that bonds the three together. The outer fabric is an ultra-high molecular weight polyethylene / polyamide 66 blended woven fabric treated with gradient water repellency. The inner fabric is a polypropylene composite nonwoven fabric treated with antibacterial and pH-indicating agents. The film layer is a polyether-polycarbonate copolymer thermoplastic polyurethane film. The adhesive layer is a double cross-linked network polyether moisture-curing polyurethane hot melt adhesive.

[0008] Preferably, the polyether-polycarbonate copolymer thermoplastic polyurethane film comprises the following components: 100 parts by weight of polyether-polycarbonate copolymer thermoplastic polyurethane resin, wherein the soft segment is copolymerized from polycarbonate diol and polytetramethylene ether diol in a molar ratio of 30-40:60-70, and the hard segment is a chain extension system of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol. 1.5-2.5 parts by weight of boron nitride nanosheets, wherein the boron nitride nanosheets are subjected to hydroxylation treatment; 4-6 parts by weight of carbodiimide-grafted polyether polyol, wherein the polycarbodiimide segments are covalently grafted onto the ends of the polytetramethylene ether glycol backbone, and the carbodiimide equivalent is 0.8-1.2 mmol / g. 0.6-1.0 parts by weight of stabilizer microcapsules, wherein the stabilizer microcapsules use a molecular-level complex of hindered phenolic antioxidants and hindered amine light stabilizers as the core material and polyurea as the shell material; 0.8-1.2 parts by weight of zinc-doped mesoporous titanium dioxide nanoparticles, with a zinc doping content of 3-5 mol%; 3-5 parts by weight of core-shell structured acrylate rubber particles, the core layer of which is cross-linked polybutyl acrylate and the shell layer of which is methyl methacrylate-glycidyl methacrylate copolymer; The fluorinated silicone oil modified polyether wax is 0.2-0.4 parts by weight, with a number-average molecular weight of 1500-2500 for its polyether segments, and its ends are perfluorohexyl-terminated.

[0009] Preferably, the double-crosslinked network polyether-type moisture-curing polyurethane hot melt adhesive comprises the following components: The main body of the double crosslinked network polyether-type moisture-curing polyurethane hot melt adhesive is 100 parts by weight. Its soft segment is polytetramethylene ether glycol with a number average molecular weight of 1800-2200, and its hard segment is a chain extender system of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol with trimethylolpropane as a trifunctional crosslinking agent. Its isocyanate index NCO / OH is 1.08-1.12, and its crosslinking density is 0.15-0.25 mmol / g. 0.5-0.8 parts by weight of silane coupling agent, wherein one end of the silane coupling agent is an isocyanate group and the other end is a trimethoxysilyl group; 2-3 parts by weight of nano-montmorillonite, wherein the nano-montmorillonite is modified with a quaternary ammonium salt type organic modifier; 1.5-2.5 parts by weight of pH-responsive carbodiimide microspheres, wherein the pH-responsive carbodiimide microspheres are cross-linked PMMA microspheres containing orthoacyl bonds, wherein the surface and pores of the pH-responsive carbodiimide microspheres are loaded with active carbodiimide groups, wherein the loading amount of carbodiimide is 0.5-0.8 mmol / g, wherein when the pH is below 6.0, the acid-sensitive orthoacyl bonds in the shell of the pH-responsive carbodiimide microspheres undergo acid-catalyzed hydrolysis and breakage, resulting in shell disintegration and release of carbodiimide active groups; 2.0-3.0 parts by weight of surface-silanized alumina nanoparticles.

[0010] Preferably, the outer fabric includes a base fabric, which is a high-density fabric made of ultra-high molecular weight polyethylene fiber and polyamide 66 fiber twisted and woven in a mass ratio of 65-75:25-35. The base fabric is treated with water-repellent finishing on its surface by silica / organosilicon hybrid gel containing carbon-carbon double bonds, and water-repellent finishing on its bottom surface by a mixed finishing solution of 20-30 g / L of CO type organosilicon-based water repellent agent and 5-10 g / L of nano silica sol.

[0011] Preferably, the inner layer fabric comprises a polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric, the surface of which is surface-finished by a finishing liquid comprising 10-20 g / L chitosan, 2-3 g / L bromocresol microcapsules, and 3-5 g / L waterborne polyurethane adhesive substrate, wherein the bromocresol microcapsules use melamine-formaldehyde resin as the shell material.

[0012] The present invention also provides a method for preparing a waterproof and breathable composite fabric, which includes the following steps: S1, Preparation of masterbatch pre-dispersion of nanofillers and functional additives: Each nanofiller is melt-blended in its corresponding polymer matrix to prepare a high-concentration masterbatch. S2, Extrusion casting of polyether-polycarbonate copolymer thermoplastic polyurethane film: The masterbatch obtained in S1, along with the matrix resin and functional additives, are extruded through a single screw extruder and cast into a moisture-permeable film with a thickness of 22-35μm. The carbodiimide grafted polyether polyol masterbatch is added in the low-temperature zone by side feeding. S3, Synthesis and Preparation of Double Crosslinked Network Polyether Moisture-Curing Polyurethane Hot Melt Adhesive: A prepolymer containing terminal isocyanate groups was synthesized using polytetramethylene ether glycol, 4,4'-diphenylmethane diisocyanate and trimethylolpropane as the main raw materials, and then functional additive masterbatch and pH-responsive carbodiimide microspheres were added to prepare the hot melt adhesive. S4, Weaving and Gradient Water Repellency Finishing of Ultra-High Molecular Weight Polyethylene / Polyamide 66 Blended Fabric: Ultra-high molecular weight polyethylene fiber and polyamide 66 fiber are twisted and woven together to form a high-density fabric, which is then subjected to a two-step gradient water repellency finishing process. S5, the molding and dual-function finishing of polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric, which is then impregnated and finished with finishing liquid. S6, Three-in-one composite pressing and curing: The ultra-high molecular weight polyethylene / polyamide 66 blended woven fabric obtained in S4 and the polyether-polycarbonate copolymer thermoplastic polyurethane film obtained in S2 are first bonded together by dot coating with the hot melt adhesive obtained in S3. Then, the resulting semi-finished product is bonded together with the polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric obtained in S5 by dot coating for the second time. After that, it is sent to a constant temperature and humidity curing chamber to complete the moisture curing, and a waterproof and breathable composite fabric is obtained.

[0013] The present invention has the following beneficial effects: This invention eliminates the root cause of ester bond hydrolysis from a materials chemistry perspective, blocks the autocatalytic acceleration loop in the degradation pathway, prevents structural weakening caused by long-term compression in stress distribution, ensures that the fabric can still withstand mechanical loads after aging in interface bonding, and provides early visual warning intervention in failure identification. This transforms the hydrolysis reaction from an unpredictable and gradual failure into a slow aging process that is visible, predictable, and controllable throughout the entire life cycle, thereby avoiding the risk of the fabric suddenly collapsing and becoming irreparable at critical moments. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of the waterproof and breathable composite fabric in this invention; Figure 2 This is a flowchart of the method for preparing waterproof and breathable composite fabric in this invention.

[0016] 1. Outer fabric; 2. Inner fabric; 3. Film layer; 4. Adhesive layer. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0019] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0020] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0022] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] A waterproof and breathable composite fabric, such as Figure 1 As shown, it includes an outer fabric 1, an inner fabric 2, a film layer 3 located between the two, and an adhesive layer 4 that bonds the three together. The outer fabric 1 is a woven fabric of ultra-high molecular weight polyethylene / polyamide 66 with gradient water-repellent treatment, the inner fabric 2 is a polypropylene composite nonwoven fabric with antibacterial and pH-indicating treatment, the film layer 3 is a polyether-polycarbonate copolymer thermoplastic polyurethane film, and the adhesive layer 4 is a double cross-linked network polyether moisture-curing polyurethane hot melt adhesive.

[0024] The polyether-polycarbonate copolymer thermoplastic polyurethane film includes the following components: 100 parts by weight of polyether-polycarbonate copolymer thermoplastic polyurethane resin, wherein the soft segment is copolymerized from polycarbonate diol and polytetramethylene ether diol in a molar ratio of 30-40:60-70, and the hard segment is a chain extension system of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol, and the film thickness is 22-35 μm; 1.5-2.5 parts by weight of boron nitride nanosheets, which are hydroxylated and have a diameter of 200-500 nm and a thickness of 3-5 nm; 4-6 parts by weight of carbodiimide-grafted polyether polyol, wherein the polycarbodiimide segment is covalently grafted to the end of the polytetramethylene ether glycol backbone, and the carbodiimide equivalent is 0.8-1.2 mmol / g; Stabilizer microcapsules 0.6-1.0 parts by weight, the microcapsules are made of a molecular-level complex of hindered phenolic antioxidants and hindered amine light stabilizers as the core material, and polyurea as the shell material, with a shell thickness of 50-100 nm; Zinc-doped mesoporous titanium dioxide nanoparticles, 0.8-1.2 parts by weight, with zinc doping amount of 3-5 mol%, particle size of 15-25 nm, and specific surface area ≥200 m² / g; 3-5 parts by weight of core-shell structured acrylate rubber particles, wherein the core layer is cross-linked polybutyl acrylate and the shell layer is methyl methacrylate-glycidyl methacrylate copolymer, with a particle size of 150-300 nm. 0.2-0.4 parts by weight of modified polyether wax containing fluorinated silicone oil, wherein the number average molecular weight of the polyether segments is 1500-2500 and the ends are perfluorohexyl-terminated.

[0025] More specifically, the double-crosslinked network polyether-based moisture-curing polyurethane hot melt adhesive comprises the following components: The main body of the double crosslinked network polyether-type moisture-curing polyurethane hot melt adhesive is 100 parts by weight, wherein the soft segment is polytetramethylene ether glycol with a number average molecular weight of 1800-2200, the hard segment is a chain extender system of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol, and trimethylolpropane is introduced as a trifunctional crosslinking agent. The isocyanate index NCO / OH is 1.08-1.12, the crosslinking density is 0.15-0.25 mmol / g, the adhesive application amount is 14-18 g / m², and it is applied by dot coating. 0.5-0.8 parts by weight of a dual-ended reactive silane coupling agent, wherein one end of the silane coupling agent is an isocyanate group and the other end is a trimethoxysilyl group, specifically isocyanate propyltrimethoxysilane; 2-3 parts by weight of organically modified nano-montmorillonite, modified with quaternary ammonium salt type organic modifier, with interlayer spacing ≥3.2nm and flake diameter of about 200nm; pH-responsive carbodiimide microspheres, 1.5-2.5 parts by weight, are cross-linked PMMA microspheres containing orthoacyl bonds. Carbodiimide active groups are loaded on the surface and in the pores of the microspheres. The particle size is 1-3 μm and the carbodiimide loading is 0.5-0.8 mmol / g. When the pH is below 6.0, the acid-sensitive orthoacyl bonds in the shell of the microspheres undergo acid-catalyzed hydrolysis and breakage, resulting in the disintegration of the shell and the release of carbodiimide active groups. 2.0-3.0 parts by weight of surface-silanized alumina nanoparticles with a particle size of 40-80 nm.

[0026] More specifically, the outer fabric 1 includes a base fabric, which is a high-density fabric made of ultra-high molecular weight polyethylene fiber and polyamide 66 fiber in a mass ratio of 65-75:25-35 and twisted together. The basic fineness is 40-70D and the fabric density is ≥400 threads / inch. The base fabric is treated with water-repellent finishing on its surface by silica / organosilicon hybrid gel containing carbon-carbon double bonds and water-repellent finishing on its bottom surface by a mixed finishing solution of 20-30g / L of C0 type organosilicon-based water-repellent agent and 5-10g / L of nano silica sol.

[0027] More specifically, the inner fabric 2 comprises a polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric, wherein the meltblown layer has a fiber diameter of 1-3μm, the spunbond layer has a fiber diameter of 15-20μm, and the total basis weight is 25-35g / m². The surface of the polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric is surface-finished by a finishing solution, which includes 10-20g / L chitosan, 2-3g / L bromocresol microcapsules, and 3-5g / L waterborne polyurethane adhesive substrate. The bromocresol microcapsules use melamine-formaldehyde resin as the shell material, have a particle size of 5-15μm, and are purple when pH≤6.5 and yellow when pH≤5.5.

[0028] This invention also provides a method for preparing a waterproof and breathable composite fabric, for use in preparing the above-mentioned waterproof and breathable composite fabric, such as... Figure 2 As shown, it includes the following steps: S1, Preparation of masterbatch pre-dispersion of nanofillers and functional additives: Each nanofiller is melt-blended in its corresponding polymer matrix to prepare a high-concentration masterbatch. Preparation of S1.1, h-BN / TPU masterbatch: Hydroxylated hexagonal boron nitride nanosheets were wet-milled and exfoliated in anhydrous ethanol using a planetary ball mill (ball-to-material ratio 10:1, speed 300 rpm, milling time 4 h) to obtain a nanosheet suspension with a diameter of 200-500 nm and a thickness of 3-5 nm. After solvent removal by rotary evaporation at 70 °C, the nanosheets were vacuum-dried at 60 °C for 12 h. The dried boron nitride nanosheets were then side-fed into the third temperature zone of a co-rotating twin-screw extruder, producing polyether-polycarbonate. Copolymerized thermoplastic polyurethane resin particles were fed through the main feed inlet. The extruder had an L / D ratio ≥ 40, a screw diameter ≥ 25 mm, and a barrel temperature distribution of 150℃ in zone 1, 165℃ in zone 2, 175℃ in zone 3, 180℃ in zone 4, and 175℃ at the die head. The screw speed was 200-250 rpm. The extruded strip was cooled in a 20℃ circulating water bath before being pelletized, with a particle size controlled at 2-3 mm. The target filler content was 25 wt%. The coefficient of variation for boron element distribution was verified to be < 12% using SEM-EDX surface scanning. S1.2, Preparation of Zn-mTiO2 / TPU Masterbatch: Zinc-doped mesoporous titanium dioxide nanoparticles were dispersed in anhydrous ethanol at 3000 rpm for 30 min using a high-speed disperser, followed by ultrasonic treatment at 500W for 15 min to break up agglomerates. After solvent removal by rotary evaporation at 60℃, the powder was vacuum dried at 50℃ for 8 h. The dried powder was fed into a co-rotating twin-screw extruder from the third temperature zone side, with the matrix resin as the main feed. The barrel temperature distribution was the same as in S1.1, the screw speed was 200 rpm, and the target filler content was 20 wt%. The extrusion pellets were then cut. It is important to note that the environment in which this fabric is stored is a light-proof environment. Therefore, during storage, the fabric / clothing is mostly in a sealed and light-proof state, and the TiO2 photocatalysis will not be activated. Even when used outdoors, the TiO2 is embedded inside the film layer, and ultraviolet light mainly acts on the surface of tens of micrometers, with limited activation of the deep TiO2. In addition, the Zn doping content is 3-5 mol%. The purpose of Zn doping is to reduce the photocatalytic activity of TiO2 while giving it dark-state antibacterial function. S1.3, Preparation of core-shell ACR / TPU masterbatch: Core-shell structured acrylic rubber particle powder and polyether-polycarbonate copolymer thermoplastic polyurethane resin particles were premixed and simultaneously fed into a co-rotating twin-screw extruder through the main feed port. The barrel temperature distribution was: zone 1 145℃, zone 2 160℃, zone 3 170℃, zone 4 175℃, and die head 170℃. The screw speed was 180 rpm, and the target filler content was 30 wt%. During extrusion, the epoxy groups of the glycidyl methacrylate unit in the shell layer reacted in situ with the matrix resin to form chemical bonds. The barrel temperature did not exceed 175℃ to avoid side reactions of the epoxy groups. FTIR monitoring was performed at 910 cm⁻¹. -1 The presence of characteristic peaks of epoxy groups confirms that the ring-opening conversion rate of GMA in the masterbatch is ≥85%. S1.4, Preparation of OMMT / PUR Masterbatch: Organically modified nano-montmorillonite and polytetramethylene ether glycol with a number average molecular weight of 1800-2200 were stirred in a double planetary stirred tank at a mass ratio of 20:80 at 80℃, 60 rpm, and -0.095 MPa for 2 h to allow polyether chains to intercalate into the interlayer of montmorillonite, achieving an interlayer spacing ≥3.2 nm, which was confirmed by X-ray diffraction. The intercalation product was mixed with moisture-curing polyurethane hot melt adhesive coarse particles on a two-roll mill at a roll temperature of 100℃ and a roll gap of 0.5 mm for 15 min, with a target filler content of 20 wt%. After the sheet was cooled, it was granulated and sealed in aluminum foil bags. The preparation of S1.5, Al2O3 / PUR masterbatch involved reacting alumina nanoparticles with γ-glycinepropyltrimethoxysilane at a mass ratio of 100:3 in a 1:1 toluene / ethanol mixed solvent at 60°C and 800 rpm for 2 hours to complete surface silanization treatment. The mixture was then filtered, washed, and dried. Silanized alumina was then mixed with moisture-curing polyurethane hot melt adhesive coarse particles on a two-roll mill at a roll temperature of 95°C and a roll gap of 0.5 mm for 10 minutes, achieving a target filler content of 20 wt%. After cooling, the sheets were granulated and sealed for packaging. S2, Extrusion casting of polyether-polycarbonate copolymer thermoplastic polyurethane film: The masterbatch obtained in S1, along with the matrix resin and functional additives, are extruded through a single screw extruder and cast into a moisture-permeable film with a thickness of 22-35μm. The carbodiimide grafted polyether polyol masterbatch is added in the low-temperature zone by side feeding. S2.1, Raw material drying: The polyether-polycarbonate copolymer thermoplastic polyurethane matrix resin and the h-BN / TPU masterbatch, Zn-mTiO2 / TPU masterbatch, and core-shell ACR / TPU masterbatch obtained in S1 are dried in a dehumidifying rotary dryer at a dew point temperature ≤-40℃ and a drying temperature of 80℃ for ≥4h, so that the moisture content is reduced to ≤300ppm, and confirmed by Karl Fischer method; S2.2, Metering and Premixing: The matrix resin and each masterbatch are metered separately using a loss-in-weight weighing scale, and the actual amount of each masterbatch is calculated according to the formula ratio; the matrix resin particles, each masterbatch, bifunctional stabilizer microcapsules and fluorinated silicone oil modified polyether wax are premixed in a drum dryer at 30 rpm for 15-20 min; carbodiimide grafted polyether polyol masterbatch is not added in this step. S2.3, Extrusion Casting: The premixed material obtained in S2.2 is fed into a single-screw extruder from the main hopper. The extruder has an L / D ratio ≥ 30, a screw diameter ≥ 45 mm, and is equipped with a side feed port and a T-shaped flat-slit die with a die width ≥ 1200 mm. The barrel temperature distribution is: Zone 1 160℃, Zone 2 175℃, Zone 3 185℃, Zone 4 190℃, Zone 5 185℃, and the die temperature is 190℃. The screw speed is 25-40 rpm. The carbodiimide-grafted polyether polyol masterbatch is added from the side feed port located in the fourth temperature zone using a loss-in-weight metering method. The temperature of the zone where the side feed port is located is separately controlled at 120-135℃, and the residence time of the carbodiimide-grafted polyether polyol masterbatch in this temperature zone does not exceed 30 seconds. S2.4, Film Forming and Online Inspection: The extruded melt is cast through a die onto a three-roll calender. The cooling roll temperature is 25-35℃, the linear speed is 8-15m / min, the roll pressure is 0.3-0.6MPa, and the roll gap is precisely controlled to the target film thickness ±2μm. A β-ray thickness gauge is used to monitor the film thickness in real time, and the roll gap is adjusted accordingly, with a target thickness of 22-35μm. Simultaneously, a Fourier transform infrared spectrometer is used to continuously monitor the film thickness at 2100cm. -1 The intensity of the characteristic peak of carbodiimide was measured to confirm that the retention rate of carbodiimide groups after processing was ≥80%. If it was lower than the threshold, the side-feeding zone temperature was reduced or the side-feeding rate was increased. S2.5, Winding: After the formed film is coated with a 15μm thick polyethylene protective film on both the top and bottom, it is automatically wound onto a 76mm diameter core using a winding machine, with a winding tension of 5-10N / m. S3, Synthesis and Preparation of Double Crosslinked Network Polyether Moisture-Curing Polyurethane Hot Melt Adhesive: A prepolymer containing terminal isocyanate groups was synthesized using polytetramethylene ether glycol, 4,4'-diphenylmethane diisocyanate and trimethylolpropane as the main raw materials, and then functional additive masterbatch and pH-responsive carbodiimide microspheres were added to prepare the hot melt adhesive. S3.1, Dehydration of polyols: Polytetramethylene ether glycol with a number average molecular weight of 1800-2200 was placed in a stainless steel reactor and dehydrated for 2 hours under nitrogen protection at a temperature of 110℃ and a vacuum of -0.098MPa. The water content was confirmed to be ≤200ppm by Karl Fischer method. S3.2, Prepolymer Synthesis: Under nitrogen protection, a measured amount of 4,4'-diphenylmethane diisocyanate is slowly added to dehydrated polytetramethylene ether glycol at 80°C. After the reaction is cooled, trimethylolpropane is added to continue the reaction. The isocyanate index NCO / OH is controlled at 1.08-1.12, and the total reaction time is 2.5-3 hours. The reaction endpoint is monitored by real-time isocyanate group titration to ensure that the prepolymer retains sufficient residual isocyanate end groups for subsequent moisture curing. S3.3, Additives are mixed in. The prepolymer is transferred to a double planetary mixer. Under the conditions of 90℃, 40rpm, and -0.095MPa, 0.5-0.8 parts by weight of propyltrimethoxysilane isocyanate, 2-3 parts by weight of OMMT / PUR masterbatch obtained in S1 (based on montmorillonite), 2.0-3.0 parts by weight of Al2O3 / PUR masterbatch obtained in S1 (based on alumina), and 1.5-2.5 parts by weight of pH-responsive carbodiimide microspheres are added sequentially. The mixture is stirred for 1 hour until homogeneous and then degassed under vacuum. S3.4, Filling: Fill the obtained hot melt adhesive into a moisture-proof and sealed container under a nitrogen atmosphere. The storage temperature is 5-25℃, and the shelf life is 6 months. Before use, the activity is confirmed by titration of isocyanate group content. S4, Weaving and Gradient Water Repellency Finishing of Ultra-High Molecular Weight Polyethylene / Polyamide 66 Blended Fabric: Ultra-high molecular weight polyethylene fiber and polyamide 66 fiber are twisted and woven together to form a high-density fabric, which is then subjected to a two-step gradient water repellency finishing process. S4.1, Yarn preparation: Ultra-high molecular weight polyethylene filament and polyamide 66 filament are twisted together at a mass ratio of 65-75:25-35 using an air-wrapped twisting machine to form a blended composite yarn. The overfeed ratio is 1.5%, the air pressure is 0.3MPa, the twisting speed is 200-350m / min, and the total fineness is 40-70D. S4.2, Weaving: The blended composite yarn is woven on a Carra plain loom in plain or twill weave, with a total warp and weft linear density of ≥400 yarns / inch, a weaving tension of 0.3-0.5 cN / dtex for warp yarns, and a machine speed of ≤400 rpm; S4.3, Refined, the woven fabric is desized. The desizing conditions are: 80℃ amylase for 90 min followed by water washing, and drying temperature ≤100℃. No alkaline boiling or bleaching is performed. S4.4, bottom layer water-repellent finishing: Prepare a finishing solution containing 20-30 g / L of C0 type organosilicon-based water-repellent agent and 5-10 g / L of nano silica sol. The nano silica sol is pre-dispersed in a high-speed disperser at 2000 rpm for 20 min and ultrasonically treated at 500W for 10 min to break up agglomerates. After the fabric is double-impregnated and double-rolled at a roll rate of 65-75%, roll pressure of 0.2-0.3 MPa, and speed of 20-30 m / min, it is baked in a hot air tenter frame at a temperature of 120-125℃ for 60-90 s. The baking temperature shall not exceed 130℃ to avoid softening of the ultra-high molecular weight polyethylene fibers. S4.5, surface water-repellent finish: A hybrid gel is prepared consisting of a siloxane precursor containing carbon-carbon double bonds, nano-silica, and a photoinitiator. The photoinitiator is used at 2 wt% of the gel solids content. The preparation process is carried out in an ice bath at 0-5℃ and stirring at 600 rpm to inhibit premature polymerization. The hybrid gel is sprayed onto the pre-treated fabric surface using an air-assisted precision spray gun with a nozzle diameter of 0.8 mm, a spraying pressure of 0.2-0.3 MPa, a spraying distance of 15-20 cm, and a coating amount of 3-5 g / m². 2 Vehicle speed 10-15m / min; immediately after spraying, it is cured in a UV curing machine with a wavelength of 365nm and a light intensity of 800-1200mW / cm². 2 Curing is completed in 3-5 seconds. After curing, the contact angle of the fabric surface is ≥150°, the arithmetic mean roughness Ra is 50-150nm, and the curing process is at room temperature, without generating thermal stress. S5, the molding and dual-function finishing of polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric, which is then impregnated and finished with finishing liquid. S5.1, SMS nonwoven fabric forming, using polypropylene with a melt index of 25-35 g / 10min as raw material, is formed on a spunbond-meltblown-spunbond combined unit. The upper spunbond layer has a fiber diameter of 15-20 μm, the middle meltblown layer has a fiber diameter of 1-3 μm, and the lower spunbond layer has a fiber diameter of 15-20 μm. The spunbonding temperature is 230-240℃, the meltblown die temperature is 260-280℃, the meltblown jet temperature is 280-300℃, the hot roller pressing temperature is 140-150℃, the linear speed is 80-120 m / min, and the total basis weight is 25-35 g / m. 2 ; S5.2, Preparation of bromocresol purple microcapsules: Bromocresol purple was dissolved in a small amount of ethanol and then added to deionized water containing emulsifier. The mixture was emulsified at 3000 rpm to form microdroplets. A melamine-formaldehyde resin prepolymer solution was slowly added dropwise. The mixture was reacted at 70℃ for 3 hours to solidify the shell. After washing, filtering and drying, the target particle size was 5-15 μm and the encapsulation rate was ≥90%. S5.3, preparation of bifunctional finishing solution: Chitosan is dissolved at a concentration of 15 g / L in deionized water containing 1 vol% acetic acid. After complete dissolution, the final pH of the finishing solution is adjusted to 6.5-7.0 with dilute NaOH solution. Then, 2-3 g / L of bromocresol microcapsules and 3-5 g / L of waterborne polyurethane adhesive substrate are added. S5.4, Impregnation and finishing: The SMS nonwoven fabric obtained in S5.1 is impregnated with the dual-function finishing liquid through a single-impregnation and single-rolling machine, with a roll rate of 80-90%, a roll pressure of 0.1-0.15MPa, and a machine speed of 15-25m / min. The roll pressure shall not exceed 0.15MPa to avoid crushing the bromocresol microcapsules. S5.5, Baking and curing: The impregnated nonwoven fabric is baked in a hot air oven at 110°C for 3 minutes to allow chitosan and water-based polyurethane bonding substrate to form a film on the fiber surface and fix the microcapsules in the gaps between the nonwoven meltblown layer fibers. The baking temperature does not exceed 120°C to avoid premature rupture of the microcapsule shell. S5.6, pH indicator function verification: Add pH 5.0 buffer solution to the surface of the finished nonwoven fabric and use a colorimeter to measure whether a color difference ΔE*≥15 appears in purple to yellow within 60s. S6, Three-in-one composite pressing and curing: The ultra-high molecular weight polyethylene / polyamide 66 blended woven fabric obtained in S4 and the polyether-polycarbonate copolymer thermoplastic polyurethane film obtained in S2 are first bonded together by dot coating with the hot melt adhesive obtained in S3. Then, the resulting semi-finished product is bonded together with the polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric obtained in S5 by dot coating for the second time. After that, it is sent into a constant temperature and humidity curing chamber to complete the moisture curing, and a waterproof and breathable composite fabric is obtained. S6.1, Hot melt adhesive melting: The double cross-linked network polyether type moisture-curing polyurethane hot melt adhesive obtained in S3 is heated to 100-110℃ and melted under nitrogen protection in the built-in melting tank of the hot melt adhesive coating machine. The melting time is ≥30min and the viscosity range after melting is 5000-15000mP·s. S6.2, First Dot Coating and Lamination: Molten hot melt adhesive is transferred in dots onto the back of the outer fabric 1 obtained in S4 using a gravure roller dot coating machine. The diameter of the adhesive dots is 0.8-1.2 mm, the spacing between the dots is 1.5-2.5 mm, and the amount of adhesive applied is 14-18 g / m². 2 The coating roller temperature is 100-110℃ and the machine speed is 15-25m / min. Immediately after coating, the adhesive surface of the outer layer fabric 1 is bonded to the moisture-permeable film obtained in S2 in a hot press roller laminating machine with a roller temperature of 80-90℃ and a roller pressure of 0.3-0.5MPa to obtain the outer layer-film composite semi-finished product. S6.3, Second dot coating and bonding: Using the same gravure roller coater, hot melt adhesive is transferred in dots onto the exposed surface of the film of the composite semi-finished product, with an adhesive application rate of 12-16 g / m². 2 After coating, the composite semi-finished product is bonded to the inner layer fabric 2 obtained in S5 in a hot press roller laminating machine. The roller temperature is 75-85℃ and the roller pressure is 0.2-0.4MPa. The roller pressure is lower than that of the first bonding to protect the bromocresol microcapsules and meltblown layer structure in the inner layer fabric 2, and a three-in-one composite fabric is obtained. S6.4, Moisture curing: The three-in-one composite fabric obtained in S6.3 is placed in a constant temperature and humidity curing chamber. The curing conditions are: temperature 23±1℃, relative humidity 65±5%, and time 48-72h. The fabric roll is placed in an unfolded hanging or loosely wound manner. During the curing process, the residual isocyanate end groups in the hot melt adhesive react with the ambient moisture to form urea bonds, forming the first crosslinking. The trimethoxysilane end of the isocyanate propyltrimethoxysilane hydrolyzes and condenses under the action of moisture to form Si-O-Si bridge bonds. Together with the second chemical crosslinking completed by the trimethylolpropane in the prepolymerization stage, they constitute a colloidal-interface integrated double crosslinked covalent network. S6.5, Curing Degree Testing: Sampling is performed every 4 hours using an attenuated total reflectance Fourier transform infrared spectrometer at 2270 cm⁻¹. -1 The characteristic peak area of ​​isocyanate is measured, and when the peak area decreases by ≥95%, the curing is considered complete, and a waterproof and breathable composite fabric is obtained.

[0029] In summary, the original polyester-type polyurethane adhesive and polyester-type film were completely replaced with a combination of polyether-polycarbonate copolymer thermoplastic polyurethane film and polyether-type moisture-curing polyurethane hot melt adhesive, which do not contain ester bonds.

[0030] The soft segment of the film is copolymerized from polycarbonate glycol and polytetramethylene ether glycol in a molar ratio of 30-40 to 60-70. The ether bonds in the polytetramethylene ether glycol segments have a much stronger resistance to hydrolysis than the densely packed ester bonds in polyester materials. The hydrolysis rate of the carbonate bonds introduced by polycarbonate glycol is only 1 / 10 to 1 / 50 of that of conventional ester bonds. At the same time, it also provides the film layer 3 with better heat and oxygen aging resistance and higher tensile strength than pure polyether materials.

[0031] The adhesive side also uses polytetramethylene ether glycol as the soft segment and 4,4'-diphenylmethane diisocyanate and 1,4-butanediol as the hard segments. There are no ester bonds on the main chain, thus eliminating the chemical groups on which the hydrolysis reaction depends. This means that even if stored in a warehouse or vehicle trunk at a temperature exceeding 40°C and a relative humidity exceeding 70% for six months or even several years, water molecules cannot find ester bond sites to attack and break. The root cause of failure, ester bond hydrolysis, is removed from the formulation.

[0032] Building upon this, to address the risk of trace residual hydrolysis that may still occur in polyether-polycarbonate copolymers under extreme conditions, and the resulting risk of autocatalytic positive feedback acceleration initiated by carboxylic acid end groups, 4 to 6 parts by weight of carbodiimide-grafted polyether polyol were added to the film layer. This component covalently grafts polycarbodiimide segments onto the ends of the polytetramethylene ether glycol backbone, which is highly compatible with the film layer matrix. The carbodiimide equivalent is 0.8 to 1.2 mmol / g. This grafting structure ensures that the carbodiimide active groups are uniformly dispersed at the molecular scale. It remains within the entire film matrix and will not migrate to the surface and lose its function due to concentration gradient during long-term storage. When any micro-region of the film generates carboxylic acid due to trace hydrolysis under extreme conditions, the carbodiimide group adjacent to that site immediately reacts with the carboxylic acid to convert it into a stable N-acylurea structure. This neutralizes and eliminates the acidic product at the moment of its generation, thus blocking the positive feedback loop of "hydrolysis to produce acid, then acid catalysis to accelerate more hydrolysis and produce more acid" at the bud stage of its initiation. The degradation rate is always maintained at an extremely low linear level and will not evolve into an exponential acceleration. Meanwhile, 1.5 to 2.5 parts by weight of acid-sensitive cracking carbodiimide microspheres were added to the adhesive formulation. The microspheres have a shell of cross-linked polymethyl methacrylate containing orthoacrylic acid bonds, and the carbodiimide active groups are loaded on the surface and in the pores of the microspheres at a loading of 0.5 to 0.8 mmol / g. Under normal neutral to weakly alkaline conditions, the orthoacrylic acid bonds are completely stable, the microspheres maintain structural integrity, and the carbodiimide active groups are sealed inside the shell without being consumed or leaked.

[0033] Once the pH value drops below 6.0 due to residual hydrolysis and acid production in a localized area of ​​the gel layer, the orthoacrylic acid acyl bond rapidly undergoes hydrolysis and breakage under acid catalysis, causing the shell layer to disintegrate within minutes. The active groups of carbodiimide are fully released into the surrounding gel layer to react with carboxylic acid. This release method, which is normally sealed and collapses immediately upon acid production, ensures that the carbodiimide will not be slowly consumed during the long normal storage period, but will instead release all the effective payload at the time and place when it is truly needed.

[0034] To address the issues of creep flow leading to localized thinning of the adhesive layer under long-term stacking and pressure or vacuum compression packaging, and stress concentration in weak areas causing delamination during initial use, the adhesive formulation incorporates trimethylolpropane as a trifunctional crosslinking agent during the prepolymerization stage. This allows the adhesive layer to possess a three-dimensional network structure woven from chemical crosslinking points formed by the reaction of the three hydroxyl groups of trimethylolpropane with isocyanates, in addition to the linear chain extension of urea bonds formed during moisture curing. The superposition of these two crosslinkings reduces the creep of the adhesive layer under continuous compression at 50°C by 60% to 70% compared to linear moisture-curing polyurethane hot melt adhesives without trimethylolpropane. Even after being subjected to pressure for several months, the adhesive dots can still maintain their original thickness distribution and shape without being flattened or thinned.

[0035] In addition, 2 to 3 parts by weight of quaternary ammonium salt-type organic modified nano-montmorillonite were added. Its high aspect ratio sheets are oriented parallel to the plane of the adhesive layer, forming a physical barrier in the thickness direction to hinder the creep flow of polyurethane chain segments. At the same time, the stacked arrangement of the sheets also prolongs the diffusion path of water molecules in the adhesive layer, reducing the diffusion coefficient of water molecules by 30-50%, thereby further slowing down the rate of water erosion of the adhesive layer.

[0036] To ensure that the interfacial bonding strength between the film and the fabric remains sufficient to withstand the peeling force caused by wearing, bending, and washing even after long-term aging, 0.5 to 0.8 parts by weight of isocyanate propyltrimethoxysilane is added to the adhesive as a bi-headed reactive silane coupling agent. The isocyanate end of this molecule directly participates in the chain extension and cross-linking reaction of polyurethane during the hot melt adhesive curing process, embedding itself into the colloidal network with covalent bonds. The trimethoxysilane end undergoes a condensation reaction with the hydroxyl groups on the film surface and the fabric fiber surface during the moisture curing stage to form Si-O-Si covalent bridge bonds. This means that the adhesive and the bonded interface no longer rely solely on physical adsorption and mechanical interlocking, but form an integrated connection through covalent chemical bonds, thereby significantly improving the wet peel strength.

[0037] In terms of film formulation, 1.5 to 2.5 parts by weight of hydroxylated hexagonal boron nitride nanosheets were added. These two-dimensional nanosheets, with a diameter of 200 to 500 nanometers and a thickness of only 3 to 5 nanometers, form a labyrinth structure in the film, which prolongs the path for liquid water molecules to penetrate from the outside to the inside of the film. Their inherent high thermal conductivity also establishes a thermally conductive network in the film, eliminating the local heat accumulation that may occur when stacked and compressed, thereby inhibiting the accelerating effect of temperature rise on the degradation reaction rate. At the same time, the nanosheets also act as a physical compatibility bridge between the two soft segments of polycarbonate diol and polytetramethylene ether diol, inhibiting the microphase separation that may occur during the processing and use of the copolymerized soft segments.

[0038] The film also incorporates 3 to 5 parts by weight of core-shell structured acrylate rubber particles. The core layer is cross-linked polybutyl acrylate, which provides elastic deformation capability, and the shell layer is a copolymer of methyl methacrylate and glycidyl methacrylate. During the masterbatch preparation stage, the epoxy groups in the shell layer undergo a ring-opening reaction with the secondary amine groups and hydroxyl groups in the thermoplastic polyurethane matrix to form chemical bonds. This ensures that these rubber particles are not simply physically mixed in the matrix but are firmly anchored by covalent bonds. When the film thins locally due to long-term pressure and is subjected to bending force during the first use, the chemically bonded core-shell particles prevent microcracks from propagating to adjacent areas, thereby preventing local weak points from developing into through-tearing.

[0039] The adhesive also contains 2.0 to 3.0 parts by weight of surface-silanized α-alumina nanoparticles. α-alumina is chemically inert and will not react with moisture during the moisture curing process. It does not produce bubbles or release alkaline substances. Although its thermal conductivity is lower than that of aluminum nitride, it is still much higher than that of polyurethane matrix, which is enough to improve the thermal conductivity of the adhesive layer by several times to eliminate local high temperature areas inside the adhesive layer when stacked and stored.

[0040] Finally, to address the dilemma of "inability to identify failure before it occurs," which leaves users unaware of any failures despite the aforementioned preventative measures, the inner layer fabric utilizes a three-layer composite nonwoven fabric of polypropylene spunbond-meltblown-spunbond treated with a dual-functional finish of chitosan and bromocresol microcapsules. Chitosan is dissolved in an aqueous solution containing 1% volumetric acetic acid, then adjusted to pH 6.5-7.0 with sodium hydroxide before adding bromocresol microcapsules and a water-based polyurethane adhesive substrate. This mixture is then applied to the nonwoven fabric surface using a low-pressure padding method. The bromocresol microcapsules are treated with melamine-formaldehyde resin. To enhance the washability of the shell material, the microcapsules, with a particle size of 5 to 15 micrometers, are embedded in the gaps between the meltblown fibers. Under normal conditions, the microcapsules are purple and blend into the background color of the nonwoven fabric, making them inconspicuous. However, when the local pH value inside the composite fabric drops below 5.5 for any reason, the bromocresol purple turns from purple to yellow, producing a visible color difference signal. Users only need to periodically turn over the lining of the clothing to observe the color, which will provide an early warning before the material undergoes interfacial delamination or film tearing. This transforms the previously imperceptible gradual degradation into visually readable information.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., 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 waterproof and breathable composite fabric, characterized by, The outer layer fabric (1) is a super high molecular weight polyethylene / polyamide 66 mixed woven fabric with gradient water repellent finishing, the inner layer fabric (2) is a polypropylene composite non-woven fabric with antibacterial and pH indicating finishing, the film layer (3) is a polyether-polycarbonate copolymer thermoplastic polyurethane film, and the adhesive layer (4) is a double crosslinking network polyether type moisture curing polyurethane hot melt adhesive.

2. The waterproof and breathable composite fabric according to claim 1, wherein, The polyether-polycarbonate copolymer thermoplastic polyurethane film comprises the following components: 100 parts by weight of polyether-polycarbonate copolymer thermoplastic polyurethane resin, the soft segment of which is copolymerized from polycarbonate diol and polytetramethylene ether glycol at a molar ratio of 30-40:60-70, and the hard segment of which is a 4,4'-diphenyl methane diisocyanate and 1,4-butanediol chain extension system; 1.5-2.5 parts by weight of boron nitride nanosheets, which are treated by hydroxylation; 4-6 parts by weight of carbodiimide grafted polyether polyol, the polycarbodiimide segment of which is covalently grafted to the end of the polytetramethylene ether glycol backbone, and the carbodiimide equivalent is 0.8-1.2 mmol / g; 0.6-1.0 parts by weight of stabilizer microcapsules, the core material of which is a molecular level complex of hindered phenolic antioxidant and hindered amine light stabilizer, and the shell material of which is polyurea; 0.8-1.2 parts by weight of zinc-doped mesoporous titanium dioxide nanoparticles, the zinc doping amount of which is 3-5 mol%; 3-5 parts by weight of core-shell structure acrylate rubber particles, the core layer of which is crosslinked polybutyl acrylate, and the shell layer of which is methyl methacrylate-glycidyl methacrylate copolymer; 0.2-0.4 parts by weight of fluorine-containing silicone oil modified polyether wax, the number average molecular weight of the polyether segment of which is 1500-2500, and the end of which is perfluorohexyl terminated.

3. The waterproof and breathable composite fabric according to claim 1, wherein, The double crosslinking network polyether type moisture curing polyurethane hot melt adhesive comprises the following components: 100 parts by weight of double crosslinking network polyether type moisture curing polyurethane hot melt adhesive main body, the soft segment of which is polytetramethylene ether glycol with a number average molecular weight of 1800-2200, the hard segment of which is a 4,4'-diphenyl methane diisocyanate and 1,4-butanediol chain extension system and introduces trimethylolpropane as a trifunctional crosslinking agent, the isocyanate index NCO / OH of which is 1.08-1.12, and the crosslinking density of which is 0.15-0.25 mmol / g; 0.5-0.8 parts by weight of silane coupling agent, one end of which is an isocyanate group, and the other end of which is a trimethoxysilane group; 2-3 parts by weight of nano-montmorillonite, which is modified with a quaternary ammonium salt type organic modifier; 1.5-2.5 parts by weight of pH-responsive carbodiimide microspheres, wherein the pH-responsive carbodiimide microspheres are cross-linked PMMA microspheres containing orthoacyl bonds, wherein the surface and pores of the pH-responsive carbodiimide microspheres are loaded with active carbodiimide groups, wherein the loading amount of carbodiimide is 0.5-0.8 mmol / g, wherein when the pH is below 6.0, the acid-sensitive orthoacyl bonds in the shell of the pH-responsive carbodiimide microspheres undergo acid-catalyzed hydrolysis and breakage, resulting in shell disintegration and release of carbodiimide active groups; 2.0-3.0 parts by weight of surface-silanized alumina nanoparticles.

4. The waterproof and breathable composite fabric according to claim 1, wherein, The outer fabric (1) includes a base fabric, which is a high-density fabric made of ultra-high molecular weight polyethylene fiber and polyamide 66 fiber twisted and woven in a mass ratio of 65-75:25-35. The base fabric is treated with water-repellent finishing on its surface by silica / organosilicon hybrid gel containing carbon-carbon double bonds and water-repellent finishing on its bottom surface by a mixed finishing liquid of 20-30 g / L of C0 type organosilicon water-repellent agent and 5-10 g / L of nano silica sol.

5. The waterproof and breathable composite fabric according to claim 1, wherein, The inner fabric (2) includes a polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric. The surface of the polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric is surface-finished by a finishing liquid. The finishing liquid includes 10-20 g / L chitosan, 2-3 g / L bromocresol microcapsules and 3-5 g / L waterborne polyurethane adhesive substrate. The bromocresol microcapsules use melamine-formaldehyde resin as the shell material.

6. A method of making a waterproof, vapor permeable composite fabric, characterized by, The method for preparing the waterproof and breathable composite fabric as described in any one of claims 1-5 comprises the following steps: S1, Preparation of masterbatch pre-dispersion of nanofillers and functional additives: Each nanofiller is melt-blended in its corresponding polymer matrix to prepare a high-concentration masterbatch. S2, Extrusion casting of polyether-polycarbonate copolymer thermoplastic polyurethane film: The masterbatch obtained in S1, along with the matrix resin and functional additives, are extruded through a single screw extruder and cast into a moisture-permeable film with a thickness of 22-35μm. The carbodiimide grafted polyether polyol masterbatch is added in the low-temperature zone by side feeding. S3, Synthesis and Preparation of Double Crosslinked Network Polyether Moisture-Curing Polyurethane Hot Melt Adhesive: A prepolymer containing terminal isocyanate groups was synthesized using polytetramethylene ether glycol, 4,4'-diphenylmethane diisocyanate and trimethylolpropane as the main raw materials, and then functional additive masterbatch and pH-responsive carbodiimide microspheres were added to prepare the hot melt adhesive. S4, Weaving and Gradient Water Repellency Finishing of Ultra-High Molecular Weight Polyethylene / Polyamide 66 Blended Fabric: Ultra-high molecular weight polyethylene fiber and polyamide 66 fiber are twisted and woven together to form a high-density fabric, which is then subjected to a two-step gradient water repellency finishing process. S5, the molding and dual-function finishing of polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric, which is then impregnated and finished with finishing liquid. S6, Three-in-one composite pressing and curing: The ultra-high molecular weight polyethylene / polyamide 66 blended woven fabric obtained in S4 and the polyether-polycarbonate copolymer thermoplastic polyurethane film obtained in S2 are first bonded together by dot coating with the hot melt adhesive obtained in S3. Then, the resulting semi-finished product is bonded together with the polypropylene spunbond-meltblown-spunbond three-layer composite nonwoven fabric obtained in S5 by dot coating for the second time. After that, it is sent to a constant temperature and humidity curing chamber to complete the moisture curing, and a waterproof and breathable composite fabric is obtained.

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