Fluorine-free waterproof and moisture-permeable composite fabric and preparation method thereof

Abstract

The present application relates to the technical field of functional textile fabric, and particularly relates to a fluorine-free waterproof and moisture-permeable composite fabric and a preparation method thereof, the preparation method is as follows: a fluorine-free sizing material is sprayed on the surface of a pretreated base fabric by printing to form a reticular functional layer, and then the fluorine-free waterproof and moisture-permeable composite fabric is obtained through segmented heating and drying treatment; the fluorine-free sizing material comprises a bio-based polyurethane, a fluorine-free hydrophobic modifier, nano-SiO2 particles, a formaldehyde-free crosslinking agent and deionized water; the fluorine-free hydrophobic modifier comprises acrylic acid and paraffin wax. The preparation method directly forms a reticular functional layer on the surface of a base material through discrete printing technology, and does not need additional film layer preparation and hot pressing composite processes, so that the production process is greatly simplified, the production cost is reduced, the fluorine-free waterproof and moisture-permeable composite fabric has good waterproof performance, air permeability, washing resistance and wear resistance, and the composite material has good softness and is more environmentally friendly.

Description

Technical Field

[0001] This invention relates to a fluorine-free waterproof and breathable composite fabric and its preparation method, belonging to the field of functional textile fabric technology. Background Technology

[0002] Waterproof and breathable fabrics are core materials for outdoor clothing and protective equipment, and their performance directly determines the wearer's comfort and protective experience. They play an irreplaceable role in outdoor sports, medical protection, and emergency rescue. The industry has an urgent need for new fabrics that combine high performance, environmental friendliness, and ease of production.

[0003] Traditional waterproof and breathable fabrics rely on a composite process of polytetrafluoroethylene (PTFE) microporous membranes and base fabrics, utilizing the microporous structure of the PTFE membrane to achieve a synergistic effect of waterproofing and breathability. However, substances such as perfluorooctanoic acid (PFOA) and perfluorinated and polyfluorinated compounds (PFAS), which are inevitably produced during PTFE production, have environmental persistence and bioaccumulation characteristics, and have been proven to pose potential hazards to the ecological environment and human health. Furthermore, the preparation of PTFE membranes requires complex swelling, stretching, and film-forming processes, making it difficult to precisely control pore size uniformity. This results in poor hydrostatic pressure resistance of the product, and the hot-pressing process during subsequent lamination with the base fabric can easily damage the microporous structure of the membrane, affecting breathability. In addition, PTFE materials produce toxic and harmful gases during high-temperature incineration and are difficult to degrade after disposal, causing secondary environmental pollution.

[0004] To overcome the environmental bottleneck of PTFE technology, the industry has gradually explored fluorine-free waterproof and breathable technology. However, existing solutions still have many shortcomings and are difficult to achieve a comprehensive balance of "environmental protection, high performance, low cost, and comfort". Fluorine-free prefabricated film composite technology, represented by products such as fluorine-free Anta film and DEEPBLUDRYFLOW+, has abandoned PFAS substances, but still continues the traditional architecture of "prefabricated independent film layer + hot-pressing composite". This type of technology requires the separate completion of multiple processes such as film layer preparation, base fabric pretreatment, and hot-pressing bonding. The production process is lengthy, which not only increases production costs, but also has problems such as the film layer micropores being easily blocked by hot melt adhesive and insufficient interlayer peel strength during the composite process.

[0005] For example, patent application CN113002102A discloses a waterproof and breathable composite fabric with a gradient pore size distribution, employing a four-layer structure (A / B / C / D) and connecting the layers via hot-melt adhesive. While this optimizes the pore size gradient design, the multi-layer composite results in a stiffer fabric feel, and the use of hot-melt adhesive may affect the smoothness of the breathable channels. Patent application CN116278280A uses an ePTFE film as a functional layer, still requiring hot-melt bonding with the base fabric and bottom fabric layers, with a curing time as long as 48 hours, leading to low production efficiency. Electrospun nanofiber membrane technology achieves waterproof and breathable functionality through continuous fiber stacking, but uneven spacing between fibers easily forms large pores, resulting in unstable waterproof performance. Furthermore, breathability is limited by fiber packing density, making improvement difficult. Additionally, this technology still requires an additional base fabric bonding process, which cannot avoid damage to the membrane structure during the bonding process. The fluorine-free waterproof fabric disclosed in patent application CN113183567A employs a multi-layer coating structure consisting of a thermoplastic resin waterproof coating, a nano-waterproof fabric layer, and a waterproof nylon fabric layer. While it offers some waterproofing, the coating thickness is significant, resulting in poor breathability and moisture permeability. Furthermore, uneven coating and peeling are prone to occur during the coating process. The medical protective clothing fabric disclosed in patent application CN111572106A uses a composite of a PU microporous membrane and a base fabric. The PU microporous membrane is 40-50 μm thick, making the fabric heavy and unsuitable for outdoor clothing or other applications requiring lightweight and softness.

[0006] In summary, existing fluorine-free waterproof and breathable technologies either rely on a composite process of pre-made membrane and base fabric, which has problems such as complex production process, stiff feel, and unstable interlayer bonding; or although the structure is simplified, there are shortcomings in terms of waterproof and breathable performance balance, washability, and environmental protection.

[0007] Therefore, developing a technology that requires no pre-filming, can be directly formed on the fabric surface, is fluorine-free and environmentally friendly, and also has high waterproof and breathable properties has become an urgent problem to be solved in the industry. Summary of the Invention

[0008] This invention addresses the shortcomings of existing technologies by providing a fluorine-free waterproof and breathable composite fabric and its preparation method. It solves the defects of existing technologies, such as reliance on pre-formed film lamination, complex production processes, insufficient environmental protection, poor breathability, or stiff hand feel, and achieves a synergistic improvement in process simplification, environmentally friendly materials, and enhanced functionality.

[0009] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing a fluorine-free waterproof and breathable composite fabric, wherein the preparation method is as follows:

[0010] A fluorine-free slurry is sprayed onto the surface of a pre-treated substrate fabric to form a mesh functional layer, and then a fluorine-free waterproof and breathable composite fabric is obtained through segmented heating and drying.

[0011] The fluorine-free slurry comprises bio-based polyurethane, a fluorine-free hydrophobic modifier, nano-SiO2 particles, an aldehyde-free crosslinking agent, and deionized water; the fluorine-free hydrophobic modifier comprises acrylic acid and paraffin wax.

[0012] Furthermore, by weight, the fluorine-free slurry comprises 20-30 parts of bio-based polyurethane, 5-8 parts of fluorine-free hydrophobic modifier, 3-5 parts of nano-SiO2 particles, 1-2 parts of formaldehyde-free crosslinking agent, and 40-60 parts of deionized water.

[0013] Furthermore, in the fluorine-free hydrophobic modifier, the mass ratio of acrylic acid to paraffin is (1-3):1.

[0014] Furthermore, the particle size of the nano-SiO2 particles is 20-50 nanometers.

[0015] Furthermore, the preparation method of the fluorine-free slurry is as follows: after mixing bio-based polyurethane, fluorine-free hydrophobic modifier, nano-SiO2 particles, formaldehyde-free crosslinking agent and deionized water, the mixture is stirred at high speed at 8000-12000r / min for 20-40min, and then homogenized by ultrasonication at 60-100kHz for 15-30min to obtain a uniformly mixed fluorine-free slurry.

[0016] Furthermore, the pretreatment process of the substrate fabric includes degreasing, drying, and plasma activation treatment in sequence. The power of the plasma activation treatment is 300-500W, and the treatment time is 30-60 seconds.

[0017] The base material is selected from at least one of nylon 66 textile fabric and polyester fiber textile fabric.

[0018] Furthermore, an array-type discrete inkjet printer is used for printing, wherein the aperture of the discrete printhead is 50-100 nanometers and the center-to-center distance between adjacent printheads is 0.1-0.2 micrometers.

[0019] Furthermore, during the printing process, the nozzle ejection frequency is controlled at 1000-2000Hz, the printing speed is 0.5-1m / min, and the substrate fabric tension is controlled at 5-8N.

[0020] Furthermore, the segmented heating and drying process sequentially includes: pre-drying treatment and baking treatment;

[0021] The pre-drying temperature is 120-140℃, the pre-drying time is 3-5 minutes, and the pre-drying is carried out by hot air circulation drying method with an air speed of 1-3m / s;

[0022] The baking temperature is 160-170℃, the baking time is 60-90 seconds, the baking process uses infrared heating, and the heating uniformity deviation is ≤±5℃.

[0023] The present invention also discloses a fluorine-free waterproof and breathable composite fabric, which is prepared by the preparation method described in the present invention.

[0024] The beneficial effects of this invention are:

[0025] The fluorine-free waterproof and breathable composite fabric and its preparation method described in this invention directly form a mesh functional layer on the surface of the substrate using discrete printing technology. This eliminates the need for additional film preparation and hot-pressing composite processes, greatly simplifying the production process, reducing production costs, and avoiding problems such as micropore blockage and structural damage during the composite process, thus significantly improving production efficiency.

[0026] The fluorine-free waterproof and breathable composite fabric of this invention has excellent environmental performance, meets global standards, uses a fluorine-free formula throughout the process, the fluorine-free waterproof and breathable slurry does not contain PFAS, there is no harmful solvent emission during the preparation process, it meets GB / T 31126 standard, and the selection of bio-based polyurethane achieves material sustainability, is degradable after disposal, and reduces environmental burden.

[0027] In the preparation method of the fluorine-free waterproof and breathable composite fabric of the present invention, the synergistic combination of the formulation of the fluorine-free slurry and the printing process conditions can precisely control the node spacing of the mesh functional layer (the node spacing is approximately 0.2 micrometers). Utilizing the size effect of "gap size smaller than liquid water droplets but larger than water vapor molecules," a highly efficient synergy between waterproofing and breathability is achieved. The waterproof index of the fluorine-free waterproof and breathable composite fabric is ≥18000mm H2O, and the moisture permeability is ≥7000g / m². 2 • After 24 hours and 50 washes, the performance retention rate exceeds 90%, far surpassing the level of existing fluorine-free fabrics and traditional composite fabrics.

[0028] The fluorine-free waterproof and breathable composite fabric of this invention has a comfortable feel and fits the wearer's needs. The mesh functional layer is directly formed on the surface of the base fabric with a thickness of only 5-15 micrometers and a porosity of 80%-85%. It does not have the stiffness caused by the extra composite thickness. The fabric is more than 20% softer than traditional composite fabrics and fits the wearer comfortably.

[0029] The fluorine-free waterproof and breathable composite fabric of this invention has a stable structure and high durability. After plasma activation treatment, the bonding force between the substrate fabric and the fluorine-free slurry is significantly improved. Combined with the curing effect of the formaldehyde-free crosslinking agent on the nodes of the network functional layers, the interlayer bonding of the fabric is strong, and the wear resistance is excellent, effectively solving the problems of easy delamination and membrane damage in traditional composite fabrics. The fluorine-free waterproof and breathable composite fabric of this invention is suitable for outdoor clothing such as windbreakers and functional protective apparel. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the cross-sectional structure of the fluorine-free waterproof and breathable composite fabric described in this invention.

[0031] Figure 2 This is an electron microscope image of the mesh functional layer described in this invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below. The present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used is for describing particular embodiments only and is not intended to limit the invention.

[0034] A method for preparing a fluorine-free waterproof and breathable composite fabric, wherein the preparation method comprises:

[0035] A fluorine-free slurry is sprayed onto the surface of a pre-treated substrate fabric using a printing method to form a mesh-like functional layer. This layer is then subjected to segmented heat drying and natural cooling to room temperature to obtain a fluorine-free waterproof and breathable composite fabric. The structure of the fluorine-free waterproof and breathable composite fabric is as follows: Figure 1 As shown.

[0036] The fluorine-free slurry comprises bio-based polyurethane, a fluorine-free hydrophobic modifier, nano-SiO2 particles, an aldehyde-free crosslinking agent, and deionized water; the fluorine-free hydrophobic modifier comprises acrylic acid and paraffin wax.

[0037] Specifically, by weight, the fluorine-free slurry comprises 20-30 parts of bio-based polyurethane, 5-8 parts of fluorine-free hydrophobic modifier, 3-5 parts of nano-SiO2 particles, 1-2 parts of formaldehyde-free crosslinking agent, and 40-60 parts of deionized water. The fluorine-free slurry contains no perfluorinated or polyfluorinated compounds (PFAS), thus preventing the generation of persistent environmental pollutants at the source and complying with GB / T 31126 standards and global environmental regulations. Among them, bio-based polyurethane, as a film-forming substrate, combines environmental sustainability with good film-forming properties. Unlike traditional petroleum-based polyurethane, it has better biodegradability. The acrylic-paraffin compound with a fluorine-free hydrophobic modifier can significantly improve the hydrophobicity of the slurry, and the compound system solves the problem of insufficient waterproof durability of a single hydrophobic modifier. Nano-SiO2 particles can enhance the structural stability and wear resistance of the functional layer, while the formaldehyde-free crosslinking agent ensures that the network structure nodes are firmly cured, avoiding the environmental hazards and health risks caused by the use of formaldehyde-containing crosslinking agents. The synergistic effect of each component makes the fluorine-free slurry not only meet the requirements for printing film formation, but also have excellent waterproof, breathable and durable properties.

[0038] Specifically, in the fluorine-free hydrophobic modifier, the mass ratio of acrylic acid to paraffin is (1-3):1. Within this ratio range, the compatibility between the modifier and the slurry can be guaranteed, while maximizing the hydrophobic synergistic effect, resulting in a stable hydrophobic layer on the fabric surface and improving the waterproof effect.

[0039] Specifically, the particle size of the nano-SiO2 particles is 20-50 nanometers. This particle size range allows the SiO2 particles to be uniformly dispersed in the slurry, forming a stable bond with the bio-based polyurethane matrix, effectively filling the tiny gaps after film formation, and improving the density and wear resistance of the functional layer. If the particle size is too large, the dispersibility will be poor, and if it is too small, it will easily agglomerate, affecting the film formation effect.

[0040] Specifically, the preparation method of the fluorine-free slurry is as follows: after mixing bio-based polyurethane, fluorine-free hydrophobic modifier, nano-SiO2 particles, formaldehyde-free crosslinking agent and deionized water, the mixture is stirred at high speed at 8000-12000 r / min for 20-40 min to quickly break up the agglomeration of the raw materials and achieve preliminary dispersion; then, it is homogenized by ultrasonication at 60-100 kHz for 15-30 min to further refine the slurry particles by ultrasonic vibration, ensuring that all components are uniformly mixed, so that the fluorine-free slurry has good printing fluidity and film-forming stability.

[0041] Specifically, the pretreatment process of the substrate fabric includes degreasing, drying, and plasma activation treatment in sequence. The power of the plasma activation treatment is 300-500W, and the treatment time is 30-60 seconds. This plasma activation treatment condition can effectively improve the surface activity of the substrate, making the surface contact angle of the substrate ≤30°, significantly enhancing the bonding force with the fluorine-free waterproof and breathable slurry, and preventing the functional layer from falling off.

[0042] The degreasing process involves soaking the substrate at room temperature for 5-15 minutes with a 1%-3% (non-ionic textile degreasing agent, such as Rudolf RUCOGEN FWK high-efficiency degreasing agent) to effectively remove oil stains from the substrate surface and prevent oil stains from affecting the adhesion of the sizing agent. The drying temperature is controlled at 50-70℃ and the drying time is 20-40 minutes to ensure that the substrate is completely dry without causing deformation or performance degradation due to high temperature.

[0043] Specifically, the substrate fabric is selected from at least one of nylon 66 textile fabric and polyester fiber textile fabric. This type of substrate has the characteristics of high strength and high abrasion resistance, which can provide stable structural support for the composite fabric and is suitable for the use needs of outdoor clothing and other scenarios.

[0044] Specifically, the printing operation is performed using an array-type discrete inkjet printer, where the aperture of the discrete printhead is 50-100 nanometers and the center-to-center distance between adjacent printheads is 0.1-0.2 micrometers.

[0045] Specifically, during the printing process, the nozzle ejection frequency is controlled at 1000-2000Hz, the printing speed is 0.5-1m / min, and the substrate tension is controlled at 5-8N.

[0046] Preferably, when the jetting frequency is high, the printing speed is controlled to be relatively slow; when the jetting frequency is low, the printing speed is controlled to be relatively fast.

[0047] More preferably, the printhead ejection frequency is controlled at 1000Hz and the printing speed is 1m / min during the printing process; or the printhead ejection frequency is controlled at 2000Hz and the printing speed is 0.5m / min during the printing process; or the printhead ejection frequency is controlled at 1500Hz and the printing speed is 0.8m / min during the printing process.

[0048] More preferably, when the water content in the fluorine-free slurry is <55% (mass content), the printing speed is 0.9-1 m / min; when the water content in the fluorine-free slurry is 55%-60% (mass content), the printing speed is 0.65-0.85 m / min; and when the water content in the fluorine-free slurry is >60% (mass content), the printing speed is 0.5-0.6 m / min.

[0049] The coordinated conditions of the printing process ensure that the node spacing in the mesh functional layer is controlled to be approximately 0.2 micrometers, the mesh gaps are a continuous structure, and the uniformity deviation of the gap size is ≤±10% (see relevant electron micrographs). Figure 2 (As shown). This size design is based on the physical principle that "the gap is smaller than that of a liquid water droplet (20-50 micrometers) and larger than that of a water vapor molecule (0.0004 micrometers)". It can effectively block the penetration of liquid water while ensuring that water vapor can pass freely, achieving a highly efficient synergy between waterproofing and breathability. At the same time, the through-type structure avoids the blockage of the breathable channels by traditional membranes or coatings, and solves the contradiction that it is difficult to achieve both waterproofing and breathability / moisture permeability in existing technologies.

[0050] The mesh functional layer has a thickness of 5-15 micrometers and a porosity of 80%-85%. This thickness allows the composite material to have better performance. If the mesh functional layer is too thin, it will result in insufficient waterproof performance and poor structural stability; if it is too thick, it will reduce the fabric's softness and moisture permeability. The 80%-85% porosity maximizes the provision of breathable and moisture-permeable channels while ensuring structural strength. Combined with the through-mesh structure, it achieves a balance between "thinness" and "high performance," significantly improving the fabric's wearing comfort.

[0051] Specifically, the segmented heating and drying process includes, in sequence, pre-drying and baking.

[0052] The pre-drying temperature is 120-140℃, the pre-drying time is 3-5 minutes, and the pre-drying is carried out by hot air circulation drying at a wind speed of 1-3m / s; this can quickly remove moisture from the slurry and avoid moisture residue that could cause defects such as bubbles and pinholes in the functional layer.

[0053] The baking process is carried out at a temperature of 160-170℃ for 60-90 seconds using infrared heating, with a heating uniformity deviation of ≤±5℃. This process promotes the cross-linking and curing of the fluorine-free slurry, enhances the structural stability and durability of the functional layer, and avoids shrinkage and deformation of the functional layer or damage to the substrate performance caused by prolonged high-temperature processing.

[0054] A fluorine-free waterproof and breathable composite fabric is disclosed, wherein the fluorine-free waterproof and breathable composite fabric is prepared using the method described in this invention. The composite fabric has a waterproof index ≥18000mm H2O (GB / T 4744-2013 standard) and a moisture permeability ≥7000g / m². 2 • 24h (JIS L1099 B1 standard), washability ≥50 times (GB / T 8629-2017 standard), and softness is improved by more than 20% compared to traditional composite fabrics. These indicators are all higher than the conventional levels of existing fluorine-free waterproof and breathable fabrics. Among them, the waterproof index and moisture permeability reach the international high-end product standards, the washability ensures the performance stability of the fabric after long-term use, and the improved softness specifically solves the pain point of stiffness in traditional composite fabrics.

[0055] More specifically, the types and sources of some of the raw materials involved in the embodiments of the present invention are as follows:

[0056] Bio-based polyurethane: Wanhua Chemical ECO13595;

[0057] Paraffin wax: Fushun Petrochemical No. 58 semi-refined paraffin wax;

[0058] Formaldehyde-free crosslinking agent: Blocked waterborne polyurethane formaldehyde-free crosslinking agent DF-819N, Liaoning Hengxing Fine Chemical Co., Ltd.;

[0059] However, the selection of the above raw material types does not constitute a limitation on the technical solution of this invention.

[0060] Example 1

[0061] The preparation method of a fluorine-free waterproof and breathable composite fabric is as follows:

[0062] (1) Pretreatment of substrate fabric: 70D nylon twill fabric is selected, soaked in degreasing agent (mass fraction 2%) at room temperature for 10 minutes, dried at 60℃ for 30 minutes, and activated by plasma treatment equipment (power 400W) for 45 seconds;

[0063] (2) Preparation of fluorine-free slurry: By weight, take the following components and mix them: 25 parts bio-based polyurethane, 6 parts fluorine-free hydrophobic modifier (acrylic acid and paraffin in a mass ratio of 2:1), 4 parts nano SiO2 (particle size 30 nm), 1.5 parts formaldehyde-free crosslinking agent, 53.5 parts deionized water, stir at 10000 r / min for 30 minutes, and homogenize by ultrasonication at 80 kHz for 20 minutes, and set aside.

[0064] (3) Direct printing: An array-type discrete inkjet printing device (80 nm nozzle diameter, 0.1 μm spacing between adjacent nozzles) is used. The jetting frequency is 1500 Hz and the printing speed is 0.8 m / min. A mesh structure is printed on the substrate surface, and the node spacing is controlled to be 0.2 μm (gap uniformity deviation ≤ ±10%).

[0065] (4) Post-treatment curing: Pre-bake at 130℃ for 4 minutes (wind speed 2m / s), bake at 165℃ for 75 seconds, and cool naturally to room temperature.

[0066] Example 2

[0067] The preparation method of a fluorine-free waterproof and breathable composite fabric is as follows:

[0068] (1) Pretreatment of substrate fabric: 280T Taslon fabric was selected, soaked in degreasing agent (mass fraction 1%) at room temperature for 15 minutes, dried at 70℃ for 40 minutes, and activated by plasma treatment equipment (power 300W) for 60 seconds.

[0069] (2) Preparation of fluorine-free slurry: Take the following components by weight and mix them: 20 parts bio-based polyurethane, 5 parts fluorine-free hydrophobic modifier (acrylic acid and paraffin in a mass ratio of 1:1), 3 parts nano SiO2 (particle size 50 nm), 1 part formaldehyde-free crosslinking agent, 40 parts deionized water, stir at 8000 r / min for 40 minutes, and homogenize by ultrasonication at 100 kHz for 15 minutes.

[0070] (3) Direct printing: An array-type discrete inkjet printing device (50 nm nozzle diameter, 0.1 μm spacing between adjacent nozzles) is used. The jetting frequency is 1300 Hz and the printing speed is 0.85 m / min. A mesh structure is printed on the substrate surface, and the node spacing is controlled to be 0.2 μm (gap uniformity deviation ≤ ±10%).

[0071] (4) Post-treatment curing: Pre-bake at 120℃ for 5 minutes (wind speed 1m / s), bake at 160℃ for 90 seconds, and cool naturally to room temperature.

[0072] Example 3

[0073] The preparation method of a fluorine-free waterproof and breathable composite fabric is as follows:

[0074] (1) Pretreatment of base material fabric: 300T spring spun fabric is selected, soaked in degreasing agent (mass fraction 3%) at room temperature for 5 minutes, dried at 50℃ for 20 minutes, and activated by plasma treatment equipment (power 500W) for 30 seconds;

[0075] (2) Preparation of fluorine-free slurry: Take the following components by weight and mix them: 30 parts bio-based polyurethane, 8 parts fluorine-free hydrophobic modifier (acrylic acid and paraffin in a mass ratio of 3:1), 5 parts nano SiO2 (particle size 20 nm), 2 parts formaldehyde-free crosslinking agent, 60 parts deionized water, stir at 12000 r / min for 20 minutes, and homogenize by ultrasonication at 60 kHz for 30 minutes, and set aside.

[0076] (3) Direct printing: An array-type discrete inkjet printing device (100 nm nozzle diameter, 0.1 μm spacing between adjacent nozzles) is used. The jetting frequency is 1700 Hz and the printing speed is 0.65 m / min. A mesh structure is printed on the substrate surface, and the node spacing is controlled to be 0.2 μm (gap uniformity deviation ≤ ±10%).

[0077] (4) Post-treatment curing: Pre-bake at 140℃ for 2 minutes (wind speed 3m / s), bake at 170℃ for 60 seconds, and cool naturally to room temperature.

[0078] Example 4

[0079] The preparation method of a fluorine-free waterproof and breathable composite fabric is as follows:

[0080] (1) Pretreatment of substrate fabric: 208T Taslon fabric was selected, and the substrate was soaked in degreasing agent (mass fraction 2%) at room temperature for 10 minutes, dried at 60℃ for 30 minutes, and activated by plasma treatment equipment (power 400W) for 45 seconds.

[0081] (2) Preparation of fluorine-free slurry: Take the following components by weight and mix them: 25 parts bio-based polyurethane, 6 parts fluorine-free hydrophobic modifier (acrylic acid and paraffin in a mass ratio of 2:1), 4 parts nano SiO2 (particle size 30 nm), 1.5 parts formaldehyde-free crosslinking agent, 60 parts deionized water, stir at 10000 r / min for 30 minutes, and homogenize by ultrasonication at 80 kHz for 20 minutes, and set aside.

[0082] (3) Direct printing: An array-type discrete inkjet printing device (80 nm nozzle diameter, 0.1 μm spacing between adjacent nozzles) is used, with a jetting frequency of 2000 Hz and a printing speed of 0.5 m / min. A mesh structure is printed on the substrate surface, and the node spacing is controlled to be 0.2 μm (gap uniformity deviation ≤ ±10%).

[0083] (4) Post-treatment curing: Pre-bake at 130℃ for 4 minutes (wind speed 2m / s), bake at 165℃ for 75 seconds, and cool naturally to room temperature.

[0084] Example 5

[0085] The preparation method of a fluorine-free waterproof and breathable composite fabric is as follows:

[0086] (1) Pretreatment of substrate fabric: 230T polyester taffeta fabric is selected, and it is soaked in degreasing agent (mass fraction 2%) at room temperature for 10 minutes, dried at 60℃ for 30 minutes, and activated by plasma treatment equipment (power 400W) for 45 seconds.

[0087] (2) Preparation of fluorine-free slurry: Take the following components by weight and mix them: 25 parts bio-based polyurethane, 6 parts fluorine-free hydrophobic modifier (acrylic acid and paraffin in a mass ratio of 2:1), 4 parts nano SiO2 (particle size 30 nm), 1.5 parts formaldehyde-free crosslinking agent, 40 parts deionized water, stir at 10000 r / min for 30 minutes, and homogenize by ultrasonication at 80 kHz for 20 minutes, and set aside.

[0088] (3) Direct printing: An array-type discrete inkjet printing device (80 nm nozzle diameter, 0.1 μm spacing between adjacent nozzles) is used. The jetting frequency is 1000 Hz and the printing speed is 1 m / min. A mesh structure is printed on the substrate surface, and the node spacing is controlled to be 0.2 μm (gap uniformity deviation ≤ ±10%).

[0089] (4) Post-treatment curing: Pre-bake at 130℃ for 4 minutes (wind speed 2m / s), bake at 165℃ for 75 seconds, and cool naturally to room temperature.

[0090] Example 6

[0091] The preparation method of a fluorine-free waterproof and breathable composite fabric is as follows:

[0092] (1) Pretreatment of substrate fabric: 70D nylon twill fabric is selected, soaked in degreasing agent (mass fraction 2%) at room temperature for 10 minutes, dried at 60℃ for 30 minutes, and activated by plasma treatment equipment (power 400W) for 45 seconds;

[0093] (2) Preparation of fluorine-free slurry: By weight, take the following components and mix them: 25 parts bio-based polyurethane, 6 parts fluorine-free hydrophobic modifier (acrylic acid and paraffin in a mass ratio of 2:1), 4 parts nano SiO2 (particle size 30 nm), 1.5 parts formaldehyde-free crosslinking agent, 53.5 parts deionized water, stir at 10000 r / min for 30 minutes, and homogenize by ultrasonication at 80 kHz for 20 minutes, and set aside.

[0094] (3) Direct printing: An array-type discrete inkjet printing device (80 nm nozzle diameter, 0.1 μm spacing between adjacent nozzles) is used, with a jetting frequency of 2000 Hz and a printing speed of 0.5 m / min. A mesh structure is printed on the substrate surface, and the node spacing is controlled to be 0.2 μm (gap uniformity deviation ≤ ±10%).

[0095] (4) Post-treatment curing: Pre-bake at 130℃ for 4 minutes (wind speed 2m / s), bake at 165℃ for 75 seconds, and cool naturally to room temperature.

[0096] Example 7

[0097] The preparation method of a fluorine-free waterproof and breathable composite fabric is as follows:

[0098] (1) Pretreatment of substrate fabric: 70D nylon twill fabric is selected, soaked in degreasing agent (mass fraction 2%) at room temperature for 10 minutes, dried at 60℃ for 30 minutes, and activated by plasma treatment equipment (power 400W) for 45 seconds;

[0099] (2) Preparation of fluorine-free slurry: By weight, take the following components and mix them: 25 parts bio-based polyurethane, 6 parts fluorine-free hydrophobic modifier (acrylic acid and paraffin in a mass ratio of 2:1), 4 parts nano SiO2 (particle size 30 nm), 1.5 parts formaldehyde-free crosslinking agent, 53.5 parts deionized water, stir at 10000 r / min for 30 minutes, and homogenize by ultrasonication at 80 kHz for 20 minutes, and set aside.

[0100] (3) Direct printing: An array-type discrete inkjet printing device (80 nm nozzle diameter, 0.1 μm spacing between adjacent nozzles) is used. The jetting frequency is 1000 Hz and the printing speed is 1 m / min. A mesh structure is printed on the substrate surface, and the node spacing is controlled to be 0.2 μm (gap uniformity deviation ≤ ±10%).

[0101] (4) Post-treatment curing: Pre-bake at 130℃ for 4 minutes (wind speed 2m / s), bake at 165℃ for 75 seconds, and cool naturally to room temperature.

[0102] Comparative Example 1

[0103] The composite material was prepared using the same method as in Example 1, except that no paraffin was added to the fluorine-free slurry in Comparative Example 1, and all the fluorine-free hydrophobic modifiers used were acrylic acid.

[0104] Comparative Example 2

[0105] The composite material was prepared using the same method as in Example 1, except that the ratio of acrylic acid to paraffin in the fluorine-free hydrophobic modifier of Comparative Example 2 was 1:4 (i.e., the amount of paraffin was increased).

[0106] Comparative Example 3

[0107] The composite material was prepared using the same method as in Example 1, except that the spraying frequency in the printing process of Comparative Example 3 was 2500 Hz (higher than the spraying frequency defined in this invention).

[0108] Comparative Example 4

[0109] The composite material was prepared using the same method as in Example 1, except that the printing speed in Comparative Example 4 was 0.2 m / min (lower than the printing speed specified in this invention).

[0110] Comparative Example 5

[0111] The composite material was prepared using the same method as in Example 1, except that no silica was added to the fluorine-free slurry in Comparative Example 5.

[0112] The composite fabrics prepared in the above embodiments and comparative examples were subjected to performance tests. The specific test results are shown in Table 1 below. The test methods involved are as follows:

[0113] Waterproofing index test: GB / T 4744-2013 standard;

[0114] Moisture permeability test: JIS L1099 B1 standard;

[0115] Water wash resistance test: GB / T 8629-2017 standard.

[0116] Table 1 Performance Test Results

[0117]

[0118] The data in the table above shows that the composite materials prepared by the method described in this invention in Examples 1-7 have excellent waterproof, breathable, washable, and abrasion-resistant properties, and also exhibit good flexibility. Furthermore, a comparison of the experimental results from Examples 1 and 6 / 7 shows that the optimal combination of the moisture content of the fluorine-free slurry and the printing conditions is more conducive to obtaining composite materials with both excellent waterproof and breathable properties, resulting in a product with superior overall performance.

[0119] The experimental data from Comparative Example 1 and Example 1 show that if paraffin is not added to the fluorine-free slurry, the waterproof performance of the composite material decreases. This is because if the fluorine-free hydrophobic modifier does not contain paraffin components, the coating surface will lack low surface energy substances provided by long-chain alkanes, resulting in an increase in the overall surface energy of the coating and a decrease in the water contact angle. At the same time, the micron-level rough structure and barrier effect formed by wax crystals are lost, and the synergistic water-enhancing microstructure with the acrylic polymer is destroyed, thus significantly reducing the static water pressure protection performance and dynamic waterproof durability of the composite material.

[0120] The experimental data from Comparative Example 2 and Example 1 show that if the proportion of paraffin added to the fluorine-free slurry is too high, the composite material becomes less flexible and its waterproof performance decreases. This is because excessive paraffin will make the mesh functional layer relatively hard, thus reducing the overall flexibility of the composite material. Moreover, the mesh functional layer is prone to cracking during the subsequent post-treatment curing process, ultimately leading to a decrease in the waterproof performance of the composite material.

[0121] The experimental data from Comparative Example 3 and Example 1 show that if the spraying frequency is too high during the printing process, the air permeability of the composite material will decrease significantly.

[0122] The experimental data from Comparative Example 4 and Example 1 show that if the printing speed is too slow during the printing process, the air permeability of the composite material will decrease significantly. Therefore, the coordination of relevant conditions during the printing process is more conducive to obtaining a composite material with excellent overall performance.

[0123] The experimental data from Comparative Example 5 and Example 1 show that if silica is not added to the fluorine-free slurry, the coating surface cannot form the necessary nanoscale rough structure, resulting in a decrease in its surface contact angle and hydrostatic pressure resistance. At the same time, the coating lacks nanoparticle reinforcement, resulting in insufficient density, mechanical strength and durability. It is prone to defects under external force or long-term use, thus significantly deteriorating the overall waterproof performance and long-term stability of the composite material.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for preparing a fluorine-free waterproof and breathable composite fabric, characterized in that, The preparation method is as follows: A fluorine-free slurry is sprayed onto the surface of a pre-treated substrate fabric to form a mesh functional layer, and then a fluorine-free waterproof and breathable composite fabric is obtained through segmented heating and drying. The fluorine-free slurry comprises bio-based polyurethane, a fluorine-free hydrophobic modifier, nano-SiO2 particles, an aldehyde-free crosslinking agent, and deionized water; the fluorine-free hydrophobic modifier comprises acrylic acid and paraffin wax, with a mass ratio of acrylic acid to paraffin wax of (1-3):

1. The pretreatment process of the substrate fabric includes degreasing, drying, and plasma activation treatment in sequence; The printing operation is carried out using an array-type discrete inkjet printer, wherein the aperture of the discrete printhead is 50-100 nanometers and the center-to-center distance between adjacent printheads is 0.1-0.2 micrometers; during the printing process, the printhead ejection frequency is controlled at 1000-2000Hz and the printing speed is 0.5-1m / min.

2. The method for preparing a fluorine-free waterproof and breathable composite fabric according to claim 1, characterized in that, By weight, the fluorine-free slurry comprises 20-30 parts of bio-based polyurethane, 5-8 parts of fluorine-free hydrophobic modifier, 3-5 parts of nano-SiO2 particles, 1-2 parts of formaldehyde-free crosslinking agent, and 40-60 parts of deionized water.

3. The method for preparing a fluorine-free waterproof and breathable composite fabric according to claim 1, characterized in that, The particle size of the nano-SiO2 particles is 20-50 nanometers.

4. The method for preparing a fluorine-free waterproof and breathable composite fabric according to claim 1, characterized in that, The method for preparing the fluorine-free slurry is as follows: after mixing bio-based polyurethane, fluorine-free hydrophobic modifier, nano-SiO2 particles, formaldehyde-free crosslinking agent and deionized water, the mixture is stirred at high speed at 8000-12000r / min for 20-40min, and then homogenized by ultrasonication at 60-100kHz for 15-30min to obtain a uniformly mixed fluorine-free slurry.

5. The method for preparing a fluorine-free waterproof and breathable composite fabric according to claim 1, characterized in that, The plasma activation treatment has a power of 300-500W and a treatment time of 30-60 seconds; The base material is selected from at least one of nylon 66 textile fabric and polyester fiber textile fabric.

6. The method for preparing a fluorine-free waterproof and breathable composite fabric according to claim 1, characterized in that, The tension of the base material fabric is controlled at 5-8N.

7. The method for preparing a fluorine-free waterproof and breathable composite fabric according to claim 1, characterized in that, The segmented heating and drying process includes, in sequence, pre-drying and baking processes; The pre-drying temperature is 120-140℃, the pre-drying time is 3-5 minutes, and the pre-drying is carried out by hot air circulation drying method with an air speed of 1-3m / s; The baking temperature is 160-170℃, the baking time is 60-90 seconds, the baking process uses infrared heating, and the heating uniformity deviation is ≤±5℃.

8. A fluorine-free waterproof and breathable composite fabric, characterized in that, The fluorine-free waterproof and breathable composite fabric is prepared by the preparation method described in any one of claims 1-7.

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