Preparation method of waterproof and breathable fabric, fabric and application thereof

Abstract

This application relates to the field of textile materials technology, and discloses a method for preparing a waterproof and breathable fabric, the fabric itself, and its applications. The method for preparing the waterproof and breathable fabric involves four main steps: base fabric preparation, film layer preparation, lamination, and finishing. In particular, a three-layer co-extrusion process forms a three-layer ultra-thin polyurethane laminate composed of first, second, and third polyurethane layers. The raw material for the second polyurethane layer contains an organosilicon-based fluorine-free waterproofing agent, embedding the waterproofing agent within the middle layer of the ultra-thin polyurethane laminate. Combined with a base fabric layer woven from recycled polyamide 7D yarn and a 0.1-0.3mm ultra-thin polyurethane laminate, the resulting fabric exhibits lightweight, high waterproofness, high breathability, and high washability, effectively solving the technical problem in existing waterproof and breathable fabrics that simultaneously satisfy lightweight, high waterproofness, high breathability, environmental friendliness, and durability.

Description

Technical Field

[0001] This application relates to the field of textile materials technology, and in particular to a method for preparing a waterproof and breathable fabric, the fabric itself, and its applications. Background Technology

[0002] Waterproof and breathable fabrics hold a vital position in the textile industry. With the rise of outdoor sports and the increasing demand for professional protection, their application scope continues to expand, finding widespread use in outdoor sportswear, professional protective equipment, and other fields. The development of this fabric provides comfort and safety in various harsh environments, driving the development of related industries.

[0003] Currently, waterproof and breathable fabrics mainly employ microporous membrane technology or polyurethane (PU) coating technology. Microporous membrane technology creates tiny pores in the membrane material, allowing water vapor to pass through while preventing liquid water from entering. Polyurethane coating technology involves applying a layer of polyurethane coating to the fabric surface, utilizing the coating's properties to achieve waterproof and breathable functionality. Furthermore, the market also utilizes methods such as increasing coating thickness and improving membrane structure to enhance the waterproof and breathable properties of fabrics.

[0004] However, these existing technologies have significant drawbacks. Traditional waterproof and breathable fabrics generally suffer from insufficient durability, and it is difficult to balance breathability and waterproofness simultaneously; increasing the waterproof performance of a fabric often reduces its breathability. Furthermore, to achieve higher water pressure resistance, it is usually necessary to increase the coating thickness or use a dense membrane structure, which leads to increased fabric weight, decreased softness, and reduced wearing comfort. Moreover, waterproofing treatments often use waterproofing agents containing perfluoroalkyl and polyfluoroalkyl substances (PFAS), which are difficult to degrade and pose potential hazards to the environment and human health, failing to meet the requirements of green and sustainable development. Summary of the Invention

[0005] To overcome at least one of the problems existing in the prior art, one objective of this application is to provide a method for preparing a waterproof and breathable fabric. This method involves four main steps: base fabric preparation, membrane preparation, lamination, and finishing. In particular, the membrane preparation step introduces a three-layer structure consisting of a first polyurethane layer, a second polyurethane layer, and a third polyurethane layer. The second polyurethane layer contains a silicone-based fluorine-free waterproofing agent, embedding the waterproofing agent within the intermediate layer of the ultra-thin polyurethane laminate. This avoids the poor wash resistance and PFAS contamination problems caused by surface spraying. Simultaneously, the combination of a base fabric layer woven from recycled polyamide 7D yarn and a 0.1~0.3 mm ultra-thin polyurethane laminate results in a waterproof and breathable fabric that is both lightweight and highly effective in waterproofing and breathability, solving the technical problem in the prior art where fabrics cannot simultaneously satisfy lightweight, high waterproofness, high breathability, and environmental friendliness. A second objective of this application is to provide a waterproof and breathable fabric prepared by the aforementioned method. A third objective of this application is to provide applications for the aforementioned waterproof and breathable fabric.

[0006] Therefore, this application adopts the following technical solution: The first aspect of this application provides a method for preparing a waterproof and breathable fabric, comprising the following steps: S1. Preparation of the base fabric layer: Recycled polyamide 7D yarn is woven into the base fabric layer; S2. Membrane preparation: A three-layer co-extrusion process is used to form an ultra-thin polyurethane laminate with a three-layer structure; S3, lamination: The ultra-thin polyurethane laminate is laminated onto the base fabric layer through a lamination process; S4. Heat setting treatment: Heat setting treatment is performed to obtain the waterproof and breathable fabric.

[0007] The three-layer structure includes a first polyurethane layer, a second polyurethane layer, and a third polyurethane layer, wherein the raw material of the second polyurethane layer contains a waterproofing agent. The waterproofing agent is a fluorine-free silicone-based waterproofing agent. The thickness of the ultrathin polyurethane laminate is 0.1~0.3 mm.

[0008] In the preparation method of the waterproof and breathable fabric of this application, recycled polyamide 7D yarn is woven into a base fabric layer, and an ultra-thin polyurethane laminate containing an organosilicon-based fluorine-free waterproofing agent in the middle layer is formed by three-layer co-extrusion. The waterproof and breathable fabric is then obtained through lamination and heat setting. The recycled polyamide fiber and organosilicon-based fluorine-free waterproofing agent used are environmentally friendly and PFAS-free. The three-layer co-extrusion process is a one-time molding process, which embeds the waterproofing agent in the middle layer of the ultra-thin polyurethane laminate, resulting in a more durable waterproof effect. The 7D yarn and 0.1~0.3 mm ultra-thin polyurethane laminate give the fabric a low weight and a soft feel, ultimately enabling the fabric to achieve good waterproof and breathable properties while maintaining lightness and comfort. This solves the problem that existing waterproof and breathable fabrics cannot simultaneously achieve lightweight, high waterproofness, high breathability, and environmental friendliness and durability.

[0009] Preferably, the "D" in the 7D yarn stands for Denier, which represents the weight in grams of 9000 meters of yarn at a standard moisture regain.

[0010] 7D is a type of ultra-fine denier fiber with a small diameter and large specific surface area. The base fabric layer woven from it is thin, soft, and has high porosity, which is beneficial to the breathability of the subsequent ultra-thin polyurethane laminate and effectively reduces the overall weight of the fabric, thus improving wearing comfort.

[0011] Preferably, the basis weight of the base fabric layer is 20-25 g / m². More preferably, the basis weight of the base fabric layer is 23-25 ​​g / m².

[0012] Preferably, the three-layer co-extrusion process includes: melting the first polyurethane layer raw material, the second polyurethane layer raw material containing the organosilicon-based fluorine-free waterproofing agent, and the third polyurethane layer raw material respectively through three extruders and then simultaneously feeding them into a common die head, where they are combined and co-extruded in one go to obtain the ultra-thin polyurethane laminate film.

[0013] Preferably, in the three-layer co-extrusion process, the feed section temperature of each extruder is 160~180℃, the compression section temperature is 180~200℃, the homogenization section temperature is 200~220℃, and the die temperature is 220~250℃. The co-extruded preform is cooled to 30~50℃ by cooling rollers and then stretched and shaped to obtain an ultra-thin polyurethane laminate with a thickness of 0.1~0.3mm. More preferably, in the three-layer co-extrusion process, the feed section temperature of each extruder is 170~180℃, the compression section temperature is 185~200℃, the homogenization section temperature is 210~220℃, and the die temperature is 230~250℃. The co-extruded preform is cooled to 35~50℃ by cooling rollers and then stretched and shaped to obtain an ultra-thin polyurethane laminate with a thickness of 0.1~0.3mm. More preferably, in the three-layer co-extrusion process, the temperature of the feeding section of each extruder is 175~180℃, the temperature of the compression section is 190~200℃, the temperature of the homogenization section is 215~220℃, and the temperature of the die head is 220~240℃. The preform after co-extrusion is cooled to 35~45℃ by cooling rollers and then stretched and shaped to obtain an ultra-thin polyurethane laminate with a thickness of 0.1~0.3mm.

[0014] In the above technical solution, the three-layer co-extrusion process is highly efficient. No adhesive is needed between the three layers; they are bonded by hot melting, resulting in strong interlayer bonding and preventing delamination. The second polyurethane layer, the middle layer, contains a silicone-based fluorine-free waterproofing agent, while the upper third polyurethane layer and the lower first polyurethane layer are pure polyurethane. This protects the silicone-based fluorine-free waterproofing agent in the middle layer from external abrasion and washing corrosion, and also helps the film maintain good mechanical properties. In-die bonding avoids the complex pre-composite process of each layer and makes the thickness more uniform. The temperatures of each section of the extruder and the die temperature of 220~250℃ ensure that the polyurethane is fully melted and has good fluidity, preventing the decomposition of the silicone-based fluorine-free waterproofing agent or the degradation of the polyurethane due to excessive temperature. Cooling to 30~50℃ allows the film preform to quickly solidify and shape, preventing adhesion or deformation. Stretching and shaping aligns the polyurethane molecular chains, improving the mechanical strength and thickness uniformity of the film, thus obtaining an ultra-thin, uniform, and high-strength polyurethane laminate of 0.1~0.3mm, providing a good foundation for subsequent lamination with the base fabric layer.

[0015] Preferably, the raw materials for the first polyurethane layer and the third polyurethane layer are both pure polyurethane.

[0016] Preferably, the second polyurethane layer raw material containing the organosilicon-based fluorine-free waterproofing agent is prepared by the following method: mixing the organosilicon-based fluorine-free waterproofing agent with pure polyurethane particles in a weight ratio of 1:(4~9), melt extruding, and granulating to obtain a concentrated masterbatch of waterproofing agent; and dry mixing the concentrated masterbatch of waterproofing agent with pure polyurethane particles in a weight ratio of (1.5~2):(5~8) to obtain the second polyurethane layer raw material.

[0017] Preferably, in the preparation of the second polyurethane layer raw material containing the organosilicon-based fluorine-free waterproofing agent, the temperature of the melt extrusion feeding section is 160-180°C, the temperature of the compression section is 180-200°C, the temperature of the homogenization section is 200-220°C, and the die temperature is 180-200°C. More preferably, in the preparation of the second polyurethane layer raw material containing the organosilicon-based fluorine-free waterproofing agent, the temperature of the melt extrusion feeding section is 165-180°C, the temperature of the compression section is 190-200°C, the temperature of the homogenization section is 200-220°C, and the die temperature is 180-200°C.

[0018] Preferably, the silicone-based fluorine-free waterproofing agent is composed of a silicone polymer, a crosslinking agent, and a surfactant in a weight ratio of (60~75):(1~10):(2~4). More preferably, the silicone-based fluorine-free waterproofing agent is composed of a silicone polymer, a crosslinking agent, and a surfactant in a weight ratio of (65~75):(3~10):(2~4).

[0019] Preferably, the organosilicon polymer is composed of aminosilane and modified silicone oil in a weight ratio of (3~6):(2~3). More preferably, the organosilicon polymer is composed of aminosilane and modified silicone oil in a weight ratio of (4.5~6):(2~3).

[0020] Preferably, the crosslinking agent is composed of acrylic acid and epoxy silane in a weight ratio of (4~5):(4~7). More preferably, the crosslinking agent is composed of acrylic acid and epoxy silane in a weight ratio of (4.5~5):(5~7).

[0021] Preferably, the surfactant is selected from at least one of Tween 20, Tween 40, octadecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride. More preferably, the surfactant is selected from at least one of Tween 20, Tween 40, and octadecyltrimethylammonium chloride. Even more preferably, the surfactant is selected from at least one of Tween 20 and Tween 40.

[0022] In the above technical solution, by first mixing and granulating the silicone-based fluorine-free waterproofing agent with pure polyurethane particles, the waterproofing agent is pre-dispersed uniformly in the polyurethane matrix, avoiding uneven dispersion or excessively high local concentration that may occur when directly mixing during co-extrusion. The granulated waterproofing agent concentrated masterbatch is then dry-mixed with pure polyurethane particles in a specific ratio and used as the raw material for the second polyurethane layer in the three-layer co-extrusion molding. This facilitates uniform dispersion within the polyurethane matrix during the subsequent high-temperature co-extrusion process, avoiding local agglomeration or uneven distribution of the waterproofing agent, thereby improving the consistency and stability of the waterproofing effect.

[0023] In the organosilicon-based fluorine-free waterproofing agent, organosilicon polymers are the main component, providing excellent hydrophobicity and a soft feel; crosslinking agents enable the waterproofing agent to form a three-dimensional network structure during film formation, which is beneficial to enhancing the bonding force with the polyurethane matrix; surfactants help maintain the stability of the system and the dispersibility of raw materials; under the specific ratio of the three components in this application, the waterproofing agent can maintain its activity under high-temperature co-extrusion conditions, giving the final fabric a long-lasting waterproof function.

[0024] The organosilicon polymer is composed of aminosilane and modified silicone oil in a weight ratio of (3~6):(2~3). The aminosilane provides reactive amino groups, which can form chemical crosslinks with the modified silicone oil, ensuring sufficient crosslinking density and hydrophobicity. The crosslinking agent is composed of acrylic acid and epoxy silane in a weight ratio of (4~5):(4~7), which combines the rapid reactivity of acrylic acid and the hydrolysis resistance of epoxy silane. The selected surfactant has good compatibility with the organosilicon polymer and the crosslinking agent, which helps to improve the dispersion and film uniformity of the system. This specific combination makes the waterproofing agent uniformly dispersed in the polyurethane intermediate layer, further improving the uniformity and durability of the fabric's waterproof performance.

[0025] Preferably, the temperature of the heat setting treatment is 150~170℃. More preferably, the temperature of the heat setting treatment is 160~170℃.

[0026] Within the temperature range of this heat setting treatment, the internal stress generated during weaving, co-extrusion stretching, and composite bonding of the base fabric and the ultra-thin polyurethane laminate can be fully eliminated without damaging the base fabric and the ultra-thin polyurethane laminate. This stabilizes the molecular structure of the fabric, helps improve the overall dimensional stability, smoothness, and shape retention of the fabric, and avoids problems such as wrinkling, shrinkage, and deformation during subsequent cutting, sewing, wearing, and washing.

[0027] The second aspect of this application provides a waterproof and breathable fabric prepared according to the method for preparing the waterproof and breathable fabric described in the first aspect of this application, wherein the weight of the waterproof and breathable fabric is 45~55 g / m2.

[0028] Waterproof and breathable fabrics with a weight of 45~55g / m2 are ultra-lightweight fabrics, meeting the stringent requirements for lightweight fabrics in outdoor sports, professional protection and other scenarios, reducing the burden of wearing and improving the flexibility of movement.

[0029] The third aspect of this application provides a waterproof and breathable fabric prepared according to the method for preparing the waterproof and breathable fabric described in the first aspect of this application, or the application of the waterproof and breathable fabric described in the second aspect of this application in the preparation of outdoor sportswear or professional protective equipment.

[0030] Compared with the prior art, this application has at least the following beneficial effects: 1) The preparation method of the waterproof and breathable fabric in this application involves four major steps: base fabric preparation, membrane preparation, lamination and finishing. In particular, the membrane preparation step employs a three-layer co-extrusion process to form a three-layer structure consisting of a first polyurethane layer, a second polyurethane layer, and a third polyurethane layer. The raw material of the second polyurethane layer contains an organosilicon-based fluorine-free waterproofing agent, which embeds the waterproofing agent within the middle layer of the ultra-thin polyurethane laminate. This avoids the problems of poor washability and PFAS contamination caused by surface spraying. Combined with the base fabric layer woven from recycled polyamide 7D yarn and the 0.1~0.3mm ultra-thin polyurethane laminate, the resulting fabric possesses lightweight, high waterproofness, high breathability, and high washability, with a weight as low as 51g / m². 2 The hydrostatic pressure reaches 20200~21900 mmH2O, and the moisture permeability reaches 50700~51400 g / m³. 2 With a static water pressure retention rate of 91.9%~95.3% after 24 hours and 20 washes, and free of PFAS, it effectively solves the technical problem that existing waterproof and breathable fabrics cannot simultaneously meet the requirements of lightweight, high waterproofness, high breathability, environmental friendliness and durability.

[0031] 2) In the preparation method of the waterproof and breathable fabric of this application, the steps of base fabric preparation, film preparation, lamination and finishing are closely connected, and there is no need for complex post-treatment such as additional coating, impregnation and multiple drying. Compared with traditional coating, film application and surface spraying processes, the production process is greatly simplified and energy consumption and wastewater discharge are reduced. The three-layer co-extrusion achieves one-time molding, with no adhesive between layers and no delamination. The film thickness is uniform and controllable, and no PFAS-containing substances are used throughout the process, which is green and environmentally friendly and suitable for industrial mass production. Detailed Implementation

[0032] The following detailed description of the contents of this application is provided through specific embodiments, comparative examples, and tables, but is not limited to all the arguments and data.

[0033] The recycled polyamide 7D yarn is sourced from BASF and is model number Loopamid. ® .

[0034] The pure polyurethane granules are sourced from Lubrizol, and the model number is Tecophilic® HP-60D-35.

[0035] Aminosilane KH-550, CAS No. 919-30-2.

[0036] The modified silicone oil is sourced from Qingdao Meiside Organosilicon Co., Ltd., and its model is MSD-9103 polyether modified silicone oil with a viscosity (25℃, CP) of 2000~5000.

[0037] Acrylic acid: CAS No. 79-10-7.

[0038] Epoxysilane KH-560, CAS No. 2530-83-8.

[0039] Surfactant Tween 40, CAS No. 9005-66-7.

[0040] Preparation Example 1: The preparation method of an organosilicon-based fluorine-free waterproofing agent includes the following steps: The organosilicon-based fluorine-free waterproofing agent was prepared by mixing 50 parts of aminosilane KH-550, 20 parts of MSD-9103 type polyether modified silicone oil (i.e., 70 parts of organosilicon polymer), 4 parts of acrylic acid, 4 parts of epoxy silane KH-560 (i.e., 8 parts of crosslinking agent), and 3 parts of surfactant Tween 40 evenly.

[0041] Preparation Example 2: The preparation method of an organosilicon-based fluorine-free waterproofing agent includes the following steps: The organosilicon-based fluorine-free waterproofing agent was prepared by mixing 45 parts of aminosilane KH-550, 20 parts of MSD-9103 type polyether modified silicone oil (i.e., 65 parts of organosilicon polymer), 4 parts of acrylic acid, 4 parts of epoxy silane KH-560 (i.e., 8 parts of crosslinking agent), and 3 parts of surfactant Tween 40 evenly.

[0042] Preparation of Comparative Example 1: The preparation method of an organosilicon-based fluorine-free waterproofing agent includes the following steps: The organosilicon-based fluorine-free waterproofing agent was prepared by mixing 40 parts of aminosilane KH-550, 35 parts of MSD-9103 type polyether modified silicone oil (i.e., 75 parts of organosilicon polymer), 4 parts of acrylic acid, 4 parts of epoxy silane KH-560 (i.e., 8 parts of crosslinking agent), and 3 parts of surfactant Tween 40 evenly.

[0043] It is particularly important to emphasize that, unless otherwise specified, the raw materials, reagents, or apparatus used in this application are all available from conventional commercial sources. Unless otherwise specified, "parts" in this application refers to parts by weight.

[0044] An embodiment of a waterproof and breathable fabric: The method for preparing the waterproof and breathable fabric of this application specifically includes the following steps: S1. Preparation of the base fabric layer: Recycled polyamide 7D yarn is woven into a fabric with a basis weight of 20~25g / m². 2 The base fabric layer; S2. Film Preparation: Organosilicon-based fluorine-free waterproofing agent and pure polyurethane particles are mixed at a weight ratio of 1:(4~9). The mixture is then melt-extruded and granulated under the following conditions: feeding section temperature 160~180℃, compression section temperature 180~200℃, homogenization section temperature 200~220℃, and die head temperature 180~200℃, to obtain concentrated masterbatch of the waterproofing agent. The concentrated masterbatch is then dry-mixed with pure polyurethane particles at a weight ratio of (1.5~2):(5~8) to obtain the second polyurethane film. Ester layer raw materials: The first polyurethane layer raw material, the second polyurethane layer raw material containing organosilicon-based fluorine-free waterproofing agent, and the third polyurethane layer raw material are respectively passed through three extruders. The feeding section temperature of each extruder is controlled at 160~180℃, the compression section temperature at 180~200℃, and the homogenization section temperature at 200~220℃. The three layers of raw materials are combined in a die head with a die head temperature of 220~250℃ and then co-extruded in one go. The film preform is cooled to 30~50℃ by cooling rollers and then stretched and shaped to obtain an ultra-thin polyurethane laminate film with a thickness of 0.1~0.3 mm. S3, Lamination: The ultra-thin polyurethane laminate obtained in step S2 is laminated onto the base fabric layer obtained in step S1 under lamination process conditions of hot pressing temperature of 160~175℃ and pressure of 0.4~0.7MPa. S4. Heat setting treatment: Heat setting treatment is carried out at 150~170℃ to obtain the waterproof and breathable fabric.

[0045] Regarding step S1, in some specific implementations, the basis weight of the base fabric layer can be 20 g / m². 2 22g / m 2 24g / m 2 Or 25g / m 2 In 7D yarn, "D" stands for Denier, which represents the weight in grams of 9000 meters of yarn at standard moisture regain.

[0046] Regarding step S2, in some specific implementations, in the preparation of the concentrated masterbatch of waterproofing agent, the weight ratio of the organosilicon-based fluorine-free waterproofing agent to pure polyurethane particles can be 1:4, 1:6, 1:7, or 1:9; the feed section temperature of the melt extrusion can be 160℃, 170℃, or 180℃; the compression section temperature can be 180℃, 185℃, 195℃, or 200℃; the homogenization section temperature can be 200℃, 210℃, or 220℃; and the die head temperature can be 180℃, 190℃, or 200℃. The silicone-based fluorine-free waterproofing agent is composed of a silicone polymer, a crosslinking agent, and a surfactant in a weight ratio of 60:1:1, 65:1:3, 70:3:4, 70:5:4, or 75:10:2. The silicone polymer consists of aminosilane and modified silicone oil in a weight ratio of 3:2, 5:2, 6:3, or 5:3. The crosslinking agent consists of acrylic acid and epoxy silane in a weight ratio of 4:5, 4.5:6, 5:7, or 4:7. The surfactant can be selected from at least one of Tween 20, Tween 40, octadecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride. In the second polyurethane layer raw material containing the silicone-based fluorine-free waterproofing agent, the weight ratio of the waterproofing agent concentrate masterbatch to pure polyurethane particles can be 1.5:5, 1.5:7, 1.5:8, 2:5, or 2:8. The first and third polyurethane layer raw materials are both pure polyurethane. The raw materials for the first, second, and third polyurethane layers are passed through three extruders. The feeding section temperature of each extruder is controlled at 160℃, 170℃, or 180℃, the compression section temperature at 180℃, 190℃, or 200℃, and the homogenization section temperature at 200℃, 210℃, or 220℃. The three layers of raw materials are combined in a die with a die temperature of 220℃, 230℃, 240℃, or 250℃ and then co-extruded in one go. The preform is cooled to 30℃, 40℃, or 50℃ by cooling rollers and then stretched and shaped to obtain an ultra-thin polyurethane laminate with a thickness of 0.1mm, 0.2mm, or 0.3mm.

[0047] Regarding step S3, in some specific implementations, the hot pressing temperature can be 160°C, 165°C, 170°C or 175°C, and the pressure can be 0.4MPa, 0.5MPa, 0.6MPa or 0.7MPa.

[0048] For step S4, in some specific implementations, the temperature of the heat setting process can be 150°C, 160°C, 165°C or 170°C.

[0049] Based on the preparation method of the waterproof and breathable fabric of this application, the following examples and comparative examples are provided: Example 1

[0050] A method for preparing a waterproof and breathable fabric specifically includes the following steps: S1. Preparation of the base fabric layer: Recycled polyamide 7D yarn is woven into a fabric with a basis weight of 24 g / m². 2 The base fabric layer; S2. Film Preparation: Pure polyurethane particles were dried in a dehumidifying dryer at 90°C for 4 hours. Then, 1 part of the silicone-based fluorine-free waterproofing agent from Preparation Example 1 was mixed evenly with 6 parts of the dried pure polyurethane particles in a high-speed mixer. The mixture was then fed into a twin-screw extruder for melt extrusion and granulation. The extruder feed section temperature was 170°C, compression section temperature was 180°C, homogenization section temperature was 210°C, and die temperature was 190°C. The screw speed was 40 rpm. The extruded strip melt was cooled in a water bath and then granulated. It was then dried in hot air at 80°C for 2 hours to obtain concentrated masterbatch of the waterproofing agent. 1.5 parts of this concentrated masterbatch and 7 parts of the dried pure polyurethane particles were added to a low-speed mixer and dry-mixed for 10 minutes until uniform to obtain the second polyurethane layer raw material containing the silicone-based fluorine-free waterproofing agent. The first polyurethane layer raw material (pure polyurethane particles) and the silicone-based fluorine-free waterproofing agent were then mixed together. The raw materials for the second and third polyurethane layers (pure polyurethane granules) were added to three single-screw extruders. The feed section temperature of each extruder was 170℃, the compression section temperature was 190℃, the homogenization section temperature was 205℃, and the die temperature was 240℃. The screw speeds of each extruder were adjusted to 35 rpm, 30 rpm, and 35 rpm, respectively. The three layers of raw materials were combined in the die and co-extruded in one go. The co-extruded film preform was cooled by a 40℃ cooling roller and entered a biaxial stretching device. It was longitudinally stretched at a temperature of 110℃, a stretching ratio of 5, and a stretching rate of 6 m / min. Transverse stretching was also performed under the same conditions. The stretched film was set in a heat-setting oven at 160℃ for 5 minutes to obtain an ultra-thin polyurethane laminate film with a total thickness of 0.2 mm.

[0051] S3, Lamination: Place the ultra-thin polyurethane laminate obtained in step S2 on top and the base fabric layer obtained in step S1 on the bottom, and align them. Perform lamination on a laminating machine with a hot pressing temperature of 165℃, a pressure of 0.6MPa, and a speed of 10m / min. S4. Setting treatment: The fabric is fed into a setting machine and heat-set at 155°C to obtain the waterproof and breathable fabric. Example 2

[0052] The preparation method of a waterproof and breathable fabric is the same as that in Example 1, except that the silicone-based fluorine-free waterproofing agent in Example 1 is used instead of the silicone-based fluorine-free waterproofing agent in Example 2. Example 3

[0053] The preparation method of a waterproof and breathable fabric is the same as in Example 1, except that the die temperature of the three-layer co-extrusion in Example 3 is 230°C. Example 4

[0054] The preparation method of a waterproof and breathable fabric is the same as in Example 1, except that the heat setting temperature in Example 4 is 170°C.

[0055] Comparative Example 1: A method for preparing a waterproof and breathable fabric is the same as in Example 1, except that in Comparative Example 1, step S2 is as follows: Pure polyurethane granules were dried in a dehumidifying dryer at 90℃ for 4 hours. Then, the polyurethane layer raw material was added to a single-screw extruder. The extruder's feed section temperature was controlled at 170℃, compression section temperature at 190℃, homogenization section temperature at 205℃, and die temperature at 240℃. The screw speed was 35 rpm. After extrusion through the die and cooling with a 40℃ cooling roller, the material entered a biaxial stretching device. Longitudinal stretching was performed at a temperature of 110℃, a stretching ratio of 5, and a stretching rate of 6 m / min. Transverse stretching was performed under the same conditions. The stretched film was then set in a heat-setting oven at 160℃ for 5 minutes to obtain a single-layer pure polyurethane film with a thickness of 0.2 mm.

[0056] Comparative Example 2: A method for preparing a waterproof and breathable fabric is the same as in Example 1, except that in Comparative Example 2, step S2 is omitted. In the preparation of the second polyurethane layer raw material containing the organosilicon-based fluorine-free waterproofing agent, the proportions of the organosilicon-based fluorine-free waterproofing agent and the dried pure polyurethane particles in Example 1 are 1 part and 10 parts, respectively.

[0057] Comparative Example 3: The preparation method of a waterproof and breathable fabric is the same as that in Example 1, except that the preparation method of the silicone-based fluorine-free waterproofing agent in Comparative Example 3 is the same as that in Comparative Example 1.

[0058] Comparative Example 4: A method for preparing a waterproof and breathable fabric is the same as in Example 1, except that the die temperature for the three-layer co-extrusion in Comparative Example 4 is 260°C.

[0059] Material performance testing: The fabrics of Examples 1-4 and Comparative Examples 1-4 were subjected to various performance tests, and the test methods are as follows: 1. Grammage: According to GB / T 4669-2008 standard, the area is taken as 100cm². 2 The sample was weighed and the weight was calculated.

[0060] 2. Static water pressure: Tested in accordance with GB / T 4744-2013 standard.

[0061] 3. Moisture permeability: Tested according to GB / T 12704.1-2021 standard.

[0062] 4. Static water pressure retention rate after 20 washes (%): In a household washing machine, after washing 20 times according to the standard washing program, the static water pressure is tested and the static water pressure retention rate is calculated according to the following formula: Static water pressure retention rate = (static water pressure after washing / static water pressure before washing) × 100%.

[0063] The test performance of Examples 1-4 and Comparative Examples 1-4 is shown in Table 1 below:

[0064] In the fabrics of Examples 1-4, the preparation method of the waterproof and breathable fabric of this application is adopted. This involves four major steps: base fabric preparation, membrane preparation, lamination, and finishing. In particular, a three-layer co-extrusion process is used to form an ultra-thin polyurethane laminate consisting of a first, second, and third polyurethane layer. The raw material of the second polyurethane layer contains a silicone-based fluorine-free waterproofing agent, allowing the waterproofing agent to be embedded in the middle layer of the ultra-thin polyurethane laminate. Combined with a base fabric layer woven from recycled polyamide 7D yarn and an ultra-thin polyurethane laminate of 0.1-0.3 mm, the fabric obtained using this method is lightweight, highly waterproof, highly breathable, and highly washable. Its weight is as low as 51 g / m², its hydrostatic pressure is as high as 20200-21900 mmH₂O, and its moisture permeability is as high as 50700-51400 mmH₂O. With a g / m2 / 24h, the hydrostatic pressure retention rate after 20 washes is as high as 91.9%~95.3%, and it does not contain PFAS. This effectively solves the technical problem that existing waterproof and breathable fabrics cannot simultaneously meet the requirements of lightweight, high waterproofness, high breathability, environmental protection and durability.

[0065] Compared to Example 1, Comparative Example 1's method for preparing waterproof and breathable fabric did not employ a three-layer co-extrusion process in step S2. Instead, it only prepared a single-layer pure polyurethane film without a waterproofing agent. The results showed that the hydrostatic pressure of Comparative Example 1 was only 4270 mmH2O, and the hydrostatic pressure retention rate dropped to 41.6% after 20 washes. This may be because without a three-layer structure and a waterproofing agent in the middle layer, the polyurethane film itself does not possess sufficient hydrophobic properties, and without the continuous action of a waterproofing agent, the initial waterproofing is extremely poor. After washing, the waterproofing performance is almost completely lost, failing to meet the basic requirements for outdoor sports or professional protection.

[0066] Compared with Example 1, Comparative Example 2 differs in that in step S2, when preparing the concentrated masterbatch of the waterproofing agent, the ratio of the organosilicon-based fluorine-free waterproofing agent to pure polyurethane particles is 1:10. The results show that the hydrostatic pressure of Comparative Example 2 is only 13000 mmH2O, and the retention rate drops to 72.7% after 20 washes. It is evident that although the ultrathin polyurethane laminate still retains the three-layer co-extrusion structure and the embedded waterproofing agent, insufficient addition of the waterproofing agent may prevent the formation of a continuous, dense hydrophobic network in the middle layer of the polyurethane, leading to a decrease in initial waterproofing performance. Furthermore, the waterproofing agent is lost more quickly after washing, resulting in significantly insufficient wash resistance.

[0067] Compared with Example 1, Comparative Example 3 used the same silicone-based fluorine-free waterproofing agent in step S2 as Comparative Example 1. The results showed that Comparative Example 3 had a hydrostatic pressure of 16900 mmH2O and a retention rate of 81.4% after 20 washes, both lower than Example 1. This may be because the proportion of aminosilane in the preparation of Comparative Example 1 was too low, while the proportion of modified silicone oil was too high, resulting in insufficient crosslinking active sites and insufficient crosslinking density in the waterproofing agent. This weakened the bonding force between the waterproofing agent and the polyurethane matrix. Simultaneously, excessive hydrophobic components may cause phase separation, reducing the waterproofing effect and wash resistance.

[0068] Compared to Example 1, Comparative Example 4 had a three-layer co-extrusion die temperature of 260°C in step S2 of its waterproof and breathable fabric preparation method. The results showed that the hydrostatic pressure of Comparative Example 4 was only 12100 mmH2O, and the retention rate after 20 washes decreased to 70.2%. This may be because the excessively high die temperature caused thermal decomposition of the silicone-based fluorine-free waterproofing agent, and the polyurethane matrix may also have undergone slight degradation. This, to some extent, damaged the chemical structure and dispersion state of the waterproofing agent in the intermediate layer, resulting in a significant decrease in both initial waterproof performance and post-wash durability.

[0069] Obviously, the above embodiments of this application are merely examples for clearly illustrating this application, and are not intended to limit the implementation of this application. For those skilled in the art, other variations or modifications can be made based on the above description. Any obvious variations or modifications derived from the technical solutions of this application are still within the protection scope of this application.

Claims

1. A method for preparing a waterproof and breathable fabric, characterized in that, Includes the following steps: S1. Preparation of the base fabric layer: Recycled polyamide 7D yarn is woven into the base fabric layer; S2. Membrane preparation: A three-layer co-extrusion process is used to form an ultra-thin polyurethane laminate with a three-layer structure; S3, lamination: The ultra-thin polyurethane laminate is laminated onto the base fabric layer through a lamination process; S4. Heat setting treatment: Perform heat setting treatment to obtain the waterproof and breathable fabric; The three-layer structure includes a first polyurethane layer, a second polyurethane layer, and a third polyurethane layer, wherein the raw material of the second polyurethane layer contains a waterproofing agent. The waterproofing agent is a fluorine-free silicone-based waterproofing agent. The thickness of the ultrathin polyurethane laminate is 0.1~0.3mm.

2. The method for preparing the waterproof and breathable fabric according to claim 1, characterized in that, The "D" in 7D yarn stands for Denier, which represents the weight in grams of 9000 meters of yarn at standard moisture regain.

3. The method for preparing the waterproof and breathable fabric according to claim 1, characterized in that, The three-layer co-extrusion process includes: melting the first polyurethane layer raw material, the second polyurethane layer raw material containing the organosilicon-based fluorine-free waterproofing agent, and the third polyurethane layer raw material through three extruders respectively, and then feeding them into a common die head, where they are combined and co-extruded in one go to obtain the ultra-thin polyurethane laminate film.

4. The method for preparing the waterproof and breathable fabric according to claim 3, characterized in that, In the three-layer co-extrusion process, the temperature of the feeding section of each extruder is 160~180℃, the temperature of the compression section is 180~200℃, the temperature of the homogenization section is 200~220℃, and the temperature of the die head is 220~250℃. The preform after co-extrusion is cooled to 30~50℃ by cooling rollers and then stretched and shaped to obtain an ultra-thin polyurethane laminate with a thickness of 0.1~0.3mm.

5. The method for preparing the waterproof and breathable fabric according to claim 3, characterized in that, The second polyurethane layer raw material containing the organosilicon-based fluorine-free waterproofing agent is prepared by the following method: the organosilicon-based fluorine-free waterproofing agent and pure polyurethane particles are mixed in a weight ratio of 1:(4~9), melt-extruded, and granulated to obtain a concentrated masterbatch of waterproofing agent; the concentrated masterbatch of waterproofing agent and pure polyurethane particles are dry-mixed in a weight ratio of (1.5~2):(5~8) to obtain the second polyurethane layer raw material.

6. The method for preparing the waterproof and breathable fabric according to claim 1, characterized in that, The organosilicon-based fluorine-free waterproofing agent is composed of an organosilicon polymer, a crosslinking agent, and a surfactant in a weight ratio of (60~75):(1~10):(2~4).

7. The method for preparing the waterproof and breathable fabric according to claim 6, characterized in that, The organosilicon polymer is composed of aminosilane and modified silicone oil in a weight ratio of (3~6):(2~3); The crosslinking agent is composed of acrylic acid and epoxy silane in a weight ratio of (4~5):(4~7); The surfactant is selected from at least one of Tween 20, Tween 40, octadecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride.

8. The method for preparing the waterproof and breathable fabric according to claim 1, characterized in that, The temperature for the heat setting process is 150~170℃.

9. A waterproof and breathable fabric, characterized in that, The waterproof and breathable fabric is prepared by the method according to any one of claims 1 to 8, wherein the weight of the waterproof and breathable fabric is 45-55 g / m². 2 .

10. The application of a waterproof and breathable fabric prepared by the method of preparing the waterproof and breathable fabric as described in claims 1 to 8, or the waterproof and breathable fabric as described in claim 9, in the preparation of outdoor sportswear or professional protective equipment.

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