Highly waterproof and breathable polyurethane membrane material and highly waterproof and breathable fabric

Abstract

The application discloses a kind of high waterproof moisture-permeable polyurethane film materials and high waterproof moisture-permeable fabric, it is related to polyurethane film material technical field, high waterproof moisture-permeable polyurethane film material, including following raw materials: polyether diol, diisocyanate, organic solvent, modified porous biochar, modified diatomite, chain extender, thickening agent, defoaming agent, ultraviolet absorber, dibutyltin dilaurate;The modified porous biochar is prepared by activating corn straw powder by potassium phosphate and potassium hydroxide in cooperation, and polyethylene glycol is added as a dispersant, and the modified porous biochar is treated by mercapto and fluorination modification;By introducing potassium phosphate in cooperation with potassium hydroxide to form an activation system in the preparation of modified porous biochar in polyurethane film material, combined with polyethylene glycol, dispersion optimization and reduction synergy are realized, and the moisture permeability, waterproofness, mechanical properties and durability of the material are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane membrane materials, and in particular to a highly waterproof and moisture-permeable polyurethane membrane material and a highly waterproof and moisture-permeable fabric. Background Art

[0002] With the development of society and the continuous improvement of people's quality of life, the demand for functional clothing is increasing. This is especially true for sportswear fabrics, such as jackets, mountaineering clothing, and raincoats, which require excellent waterproof and breathable properties. This not only requires preventing rain and snow from penetrating the fabric, but also ensures that sweat excreted by the human body is transferred out of the body through the fabric in the form of water vapor to ensure wearing comfort. In recent years, waterproof and breathable fabrics have rapidly developed, and their application is no longer limited to military supplies and medical protective equipment, but is also rapidly expanding into outdoor leisure sportswear and equipment.

[0003] For example, the patent with application number CN202411110081.0, a high-performance waterproof and breathable polyurethane membrane material and its preparation method, discloses a high-performance waterproof and breathable polyurethane membrane material and its preparation method, wherein modified porous biochar is prepared by hydrothermal carbonization, and diatomaceous earth grafted hydrophilic groups are introduced. Although the moisture permeability and water pressure resistance are improved to a certain extent, there are still problems such as a single potassium hydroxide activation system that easily leads to excessive etching of the carbon skeleton, poor pore connectivity, easy collapse, weak interfacial bonding force, and the difficulty in balancing liquid water barrier capacity and moisture permeability efficiency in traditional polyurethane membrane materials. Summary of the Invention

[0004] The embodiments of the present application provide a highly waterproof and breathable polyurethane membrane material and a highly waterproof and breathable fabric. By introducing potassium phosphate and potassium hydroxide to form an activation system in the preparation of modified porous biochar of the polyurethane membrane material, and combining with polyethylene glycol to achieve dispersion optimization and reduction synergy, the problems of traditional polyurethane membranes in which it is difficult to balance moisture permeability and waterproofness, insufficient mechanical properties and poor durability are solved, efficient water vapor diffusion and liquid water barrier are achieved, interfacial bonding strength is enhanced, and material strength and water washability are improved, thereby improving the overall performance of the polyurethane membrane material.

[0005] The present application provides a highly waterproof and breathable polyurethane membrane material, comprising the following raw materials, in parts by weight: 70 parts of polyether diol, 45 parts of diisocyanate, 45 parts of organic solvent, 12 parts of modified porous biochar, 6 parts of modified diatomaceous earth, 8 parts of chain extender, 2.5 parts of thickener, 1.5 parts of defoamer, 0.15 parts of ultraviolet absorber, and 0.08 parts of dibutyltin dilaurate;

[0006] The preparation of the modified porous biochar comprises the following steps:

[0007] S1. Corn straw powder, urea, cetyl ammonium bromide, potassium phosphate, and polyethylene glycol were mixed and ball-milled, and then subjected to a hydrothermal reaction, calcined with potassium hydroxide, and acid-washed to produce porous biochar;

[0008] S2. thiolating the porous biochar with γ-mercaptopropyltrimethoxysilane to obtain thiol-modified porous biochar;

[0009] S3. Under ultraviolet light, the thiol-modified porous biochar reacts with 2-(trifluoromethyl)acrylic acid to produce a thiol-ene reaction to obtain modified porous biochar.

[0010] Furthermore, the mass ratio of corn straw powder to potassium phosphate is 70-80:5-8.

[0011] Furthermore, the added amount of polyethylene glycol is 20%-30% of the mass of potassium phosphate.

[0012] Furthermore, the potassium phosphate includes fine particles with a particle size of 3 μm and coarse particles with a particle size of 5 μm, and the mass ratio of the fine particles to the coarse particles is 7:3.

[0013] Furthermore, the polyethylene glycol includes high molecular weight polyethylene glycol and low molecular weight polyethylene glycol, the high molecular weight is 6000, the low molecular weight is 2000, and the mass ratio of the high molecular weight polyethylene glycol to the low molecular weight polyethylene glycol is 3:2.

[0014] Furthermore, potassium phosphates of different particle sizes and polyethylene glycols of different molecular weights are combined in step S1 and then added in stages. Specifically, fine-particle potassium phosphate and high-molecular-weight polyethylene glycol are first premixed and then ball-milled. Then, coarse-particle potassium phosphate and low-molecular-weight polyethylene glycol are added by ultrasonic dispersion in the middle stage of the reaction, i.e., after 1 hour of hydrothermal reaction.

[0015] Furthermore, the frequency of ultrasonic dispersion was 50 kHz, the power was 350 W, and the time was 15 min.

[0016] Furthermore, the polyurethane film material has a double-layer structure, including a bottom layer and a surface layer;

[0017] Among them, when the modified porous biochar in the bottom layer is prepared, potassium phosphate is fine particles and polyethylene glycol is high molecular weight polyethylene glycol; when the modified porous biochar in the surface layer is prepared, potassium phosphate is coarse particles and polyethylene glycol is low molecular weight polyethylene glycol.

[0018] Furthermore, the preparation method of the highly waterproof and moisture-permeable polyurethane film material specifically comprises the following steps:

[0019] Add polyether diol and organic solvent into a reactor, add diisocyanate, ultraviolet absorber and dibutyltin dilaurate under nitrogen protection, and stir to react at 65-75°C. When the content of NCO group reaches 7%, add chain extender, modified porous biochar, modified diatomaceous earth, defoamer and thickener, and continue to react for 1-2 hours. After the reaction is completed, pour it onto release paper, use a scraper to scrape out a thin film on the surface of the release paper, and then dry it in a 90-100°C oven to form a film to obtain the highly waterproof and moisture-permeable polyurethane membrane material.

[0020] A highly waterproof and breathable fabric, which is made of polyurethane membrane material and laminated or coated on the surface of a fabric substrate.

[0021] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0022] First, by introducing potassium phosphate into the preparation of modified porous biochar, potassium phosphate and KOH work together to balance pore formation and structural stability. The hydrophilic-hydrophobic balanced surface enables the selective passage of water vapor / liquid water, while also achieving covalent bond-strengthening interfacial bonding, improving material strength and water washability, thereby enhancing the overall performance of the polyurethane membrane material.

[0023] Secondly, by introducing polyethylene glycol, the dispersion optimization and reduction synergy are achieved. Polyethylene glycol wraps potassium phosphate particles through hydrogen bonding, inhibits agglomeration, improves mixing uniformity, and decomposes at high temperature to generate reducing gas, which reacts with the decomposition product of potassium phosphate (K2O) to generate active K + , enhance the carbon skeleton etching ability, and also promote graphitization and further optimize the pore structure;

[0024] Third, by adding potassium phosphate of different particle sizes in stages and combining it with the dynamic dispersion technology of polyethylene glycol, the microstructure is further optimized. Through the multi-scale synergistic etching of biochar by potassium phosphate, fine particles are initially premixed with polyethylene glycol and then evenly dispersed, preferentially etching the carbon skeleton to form micropores, providing channels for rapid diffusion of water vapor; coarse particles are added in the middle stage and dispersed with the help of ultrasound, constructing a mesoporous skeleton in the carbon skeleton as a water vapor buffer zone to reduce diffusion resistance;

[0025] Fourthly, the dispersion and etching processes are optimized through the reverse combination of polyethylene glycol molecular weight and potassium phosphate particle size; among them, the low molecular weight short chain is permeable. Since the PEG-2000 molecular chain is short and has low viscosity, it can quickly penetrate the gaps between coarse particles, ensuring uniform dispersion of potassium phosphate and avoiding local aggregation. In addition, the short chain molecules carry potassium phosphate deep into the gaps between biochar fibers to form regular mesopores, prevent large pores from being blocked, and improve etching uniformity; the high molecular weight long chain has a significant steric hindrance effect. Since the PEG-6000 molecular chain is long and has strong adsorption, it can wrap around fine particles, thereby inhibiting their agglomeration due to their high specific surface area, promoting uniform dispersion of fine particles, and preferentially etching biochar, thereby forming micropores and providing channels for rapid diffusion of water vapor. DETAILED DESCRIPTION

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains; the terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0027] Example 1: A highly waterproof and breathable polyurethane film material, comprising the following raw materials in parts by weight:

[0028] 70 parts of polyether diol, 45 parts of diisocyanate, 45 parts of organic solvent, 12 parts of modified porous biochar, 6 parts of modified diatomaceous earth, 8 parts of chain extender, 2.5 parts of thickener, 1.5 parts of defoamer, 0.15 parts of UV absorber, 0.08 parts of dibutyltin dilaurate;

[0029] Among them, the modified diatomaceous earth is obtained by treating with a silane coupling agent and then grafting with 2-acrylamido-2-methylpropanesulfonic acid;

[0030] The method for preparing the modified porous biochar comprises the following steps:

[0031] S1. Mix corn straw powder, urea, cetyl ammonium bromide, and potassium phosphate, and ball-mill to obtain a mixed material;

[0032] The mixed material is dispersed in deionized water, stirred to form a suspension, and subjected to a hydrothermal reaction. Under nitrogen protection, the temperature is increased and then kept warm to obtain a hydrothermal product;

[0033] The hydrothermal product is washed and dried to obtain a solid product, which is mixed with potassium hydroxide and calcined in a nitrogen atmosphere. After the calcination, it is soaked in a nitric acid solution, and then washed and dried to obtain porous biochar;

[0034] The mass ratio of corn straw powder, deionized water, urea, cetyl ammonium bromide, and potassium phosphate is 70-80:1000:40-50:5-10:5-8; the ball milling time is 30 minutes and the rotation speed is 300 rpm;

[0035] Under nitrogen protection, the temperature was raised to 200-210°C at a rate of 2°C / min and the reaction time was kept at this temperature for 5-6 hours;

[0036] The mass ratio of solid product to potassium hydroxide is 20-30:12-18, the calcination temperature is 650-750°C, the time is 2-3h, and the heating rate is 5°C / min;

[0037] S2, adding the porous biochar to an ethanol aqueous solution, then adding γ-mercaptopropyltrimethoxysilane, stirring and reacting, filtering, washing, and drying after the reaction is completed to obtain the thiolated porous biochar;

[0038] The mass ratio of porous biochar to γ-mercaptopropyltrimethoxysilane is 20-30:2-4, the stirring reaction temperature is 60-70°C, and the reaction time is 1-2 hours;

[0039] S3, adding DMF to the thiol-modified porous biochar, followed by adding 2-(trifluoromethyl)acrylic acid and benzophenone, and carrying out a thiol-ene reaction under ultraviolet light. After the reaction is completed, filtering, washing, and drying to obtain the modified porous biochar;

[0040] The mass ratio of thiol-modified porous biochar, 2-(trifluoromethyl)acrylic acid, and benzophenone is 20-30:1.4-2.8:0.1-0.2, and the intensity of ultraviolet light is 500-600 mW / cm 2 The temperature of the mercapto-ene reaction is 40-50°C and the time is 20-30 minutes.

[0041] The preparation method of the highly waterproof and moisture-permeable polyurethane film material specifically comprises the following steps:

[0042] Add polyether diol and organic solvent into a reactor, add diisocyanate, ultraviolet absorber and dibutyltin dilaurate under nitrogen protection, and stir to react at 65-75°C. When the content of NCO group reaches 7%, add chain extender, modified porous biochar, modified diatomaceous earth, defoamer and thickener, and continue to react for 1-2 hours. After the reaction is completed, pour it onto release paper, use a scraper to scrape out a thin film on the surface of the release paper, and then dry it in a 90-100°C oven to form a film to obtain the highly waterproof and moisture-permeable polyurethane membrane material.

[0043] Experiments were conducted on the technical solution of Example 1, which were divided into Experiment 1, Experiment 2 and Experiment 3. The only difference between Experiment 1, Experiment 2 and Experiment 3 was the amount of potassium phosphate used. Potassium phosphate was not added in the comparative example.

[0044] The experiment includes the following raw materials by weight: 70 parts of polyoxypropylene ether diol with a molecular weight of 3000, 45 parts of isophorone diisocyanate, 45 parts of ethyl acetate, 12 parts of modified porous biochar, 6 parts of modified diatomaceous earth, 8 parts of ethylene glycol, 2.5 parts of polyurethane associative thickener, 1.5 parts of silicone polyether defoamer, 0.15 parts of UV-9, and 0.08 parts of dibutyltin dilaurate;

[0045] The experimental parameters for preparing the modified porous biochar are specifically as follows:

[0046] Experiment 1: The mass ratio of corn straw powder, deionized water, urea, cetyl ammonium bromide, and potassium phosphate is 75:1000:45:8:5;

[0047] Experiment 2: The mass ratio of corn straw powder, deionized water, urea, cetyl ammonium bromide, and potassium phosphate was 75:1000:45:8:8;

[0048] Experiment 3: The mass ratio of corn straw powder, deionized water, urea, cetyl ammonium bromide, and potassium phosphate was 75:1000:45:8:6.5;

[0049] In step S1, under nitrogen protection, the temperature was raised to 205°C at a rate of 2°C / min, and the reaction time was kept at this temperature for 5.5 hours;

[0050] The mass ratio of solid product to potassium hydroxide was 25:15; the calcination temperature was 720°C, the time was 2.5 h, and the heating rate was 5°C / min;

[0051] After calcination, the product was immersed in 10 wt% nitric acid for 1.5 h, washed by centrifugation until neutral, and dried to obtain porous biochar;

[0052] In step S2, the porous biochar and γ-mercaptopropyltrimethoxysilane are reacted at a mass ratio of 25:3 in ethanol / water at a mass ratio of 8:2 at 65° C. for 1.5 h;

[0053] In step S3, the mass ratio of thiolated porous biochar, 2-(trifluoromethyl)acrylic acid, and benzophenone is 25:2.1:0.15, and the intensity of ultraviolet light is 550 mW / cm 2 , the temperature of mercapto-ene reaction is 45°C and the time is 25 min;

[0054] Preparation of the highly waterproof and moisture-permeable polyurethane membrane material:

[0055] The raw materials were weighed according to the above formula, and polypropylene oxide ether diol with a molecular weight of 3000 and ethyl acetate were added to the reactor. Under nitrogen protection, isophorone diisocyanate, UV-9, and dibutyltin dilaurate were added, and the reaction was stirred at 70°C. When the content of the NCO group reached 7%, ethylene glycol, modified porous biochar, diatomaceous earth, silicone polyether defoamer, and polyurethane associative thickener were added, and the reaction was continued for 1.5 hours. After the reaction was completed, it was poured onto release paper, and a thin film was scraped out on the surface of the release paper with a scraper. It was then dried in a 95°C oven to form a film to obtain the highly waterproof and moisture-permeable polyurethane membrane material.

[0056] The highly waterproof and breathable polyurethane membrane materials prepared in the above comparative example and experiments 1 to 3 were subjected to performance tests, wherein the breaking strength and elongation at break were tested in accordance with GB / T 3923.1-2013 "Tensile properties of textile fabrics - Part 1: Determination of breaking strength and elongation at break (strip method)".

[0057] The moisture permeability is tested with reference to GB / T 12704.2-2009 “Test method for moisture permeability of textile fabrics - Part 2: Evaporation method”;

[0058] Hydrostatic pressure resistance is tested in accordance with GB / T 4744-2013 “Testing and evaluation of water resistance of textiles - Hydrostatic pressure method”;

[0059] The water pressure resistance retention rate after washing was tested under simulated water washing conditions: 40°C, 15 min × 20 times. After centrifugal dehydration, the hydrostatic pressure resistance test was performed again. The water pressure resistance retention rate after washing was calculated. The results are shown in Table 1:

[0060] Table 1

[0061]

[0062] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0063] By introducing potassium phosphate to achieve chemical activation synergy and interface bonding strengthening, the moisture permeability-waterproof balance and durability of the polyurethane membrane material are improved. First, potassium phosphate and potassium hydroxide form a synergistic activation system during high-temperature roasting. Potassium phosphate decomposes into K2O and P2O5 during the high-temperature hydrothermal and roasting process. The decomposition products and potassium hydroxide jointly etch the cellulose and lignin in the corn straw to form a hierarchical porous structure (micropores dominate, mesopores assist), realizing pore regulation. K2O acts as an alkaline activator and etches the carbon skeleton together with potassium hydroxide to form micropores (about 0.5-2nm), while P2O5 reacts with carbon to form pyrophosphate (K4P2O7), which stabilizes the carbon layer structure at high temperature, forms a rigid skeleton, inhibits the shrinkage of the carbon layer, and thus inhibits the collapse of the pore wall, and improves the micropore retention rate (about 60%-85%). In addition, K + Inserted between carbon layers, it expands the interlayer spacing, forms more open pores, and improves moisture permeability by 12.2%;

[0064] Secondly, phosphate (-PO4 3- ) Modify the biochar surface through chemical bonding to enhance its hydrophilicity and promote the water vapor adsorption-desorption cycle. In the subsequent thiol (-SH) and fluorination (-CF3) modifications, the phosphate groups cooperate with the hydrophobic groups to form a gradient wetting surface (contact angle of about 142°), blocking liquid water but allowing water vapor to pass through;

[0065] Third, the weak acidity of phosphate and the strong alkalinity of potassium hydroxide complement each other to avoid the collapse of pore walls caused by excessive corrosion, and the specific surface area increases from 980m 2 / g increased to about 1350m 2 / g, and potassium phosphate can provide part of K + , thereby reducing the amount of potassium hydroxide used and avoiding the decrease in pore connectivity caused by excessive corrosion of potassium hydroxide. In addition, potassium phosphate, as a hard particle, promotes the uniform mixing of corn straw powder and activator during ball milling, reduces local agglomeration, and improves activation efficiency. The phosphate groups on the surface of biochar can also react with -NCO in polyurethane to form PO-NH- covalent bonds, thereby improving the compatibility between biochar and the matrix, enhancing the interfacial bonding force, improving the fracture strength, and reducing water washing and peeling.

[0066] The introduction of potassium phosphate has the following effects on improving the performance of polyurethane membrane materials:

[0067] The moisture permeability is increased by 12.2%. The hierarchical pores in the modified porous biochar provide fast diffusion channels, and the mesopores serve as water vapor buffers. The surface hydrophilic groups - PO4 3- Enhance water molecule adsorption and increase moisture permeability;

[0068] The hydrostatic pressure resistance is increased by about 16.3%. Liquid water has difficulty penetrating most pores due to surface tension. At the same time, the -CF3 group works together with the phosphate to block water droplet penetration.

[0069] Improved mechanical properties and durability, improved elongation at break and water washing retention, -PO4 3- It forms PO-NH- covalent bonds with the -NCO groups of polyurethane, enhancing interfacial bonding. At the same time, the mesopores (2-5nm) of the porous biochar are embedded in the polyurethane molecular chains, which can resist water washing and stripping.

[0070] By introducing potassium phosphate into the preparation of modified porous biochar, potassium phosphate works synergistically with KOH to take into account both pore generation and structural stability. The hydrophilic-hydrophobic balanced surface enables the selective passage of water vapor / liquid water, while achieving covalent bond-strengthened interface bonding, improving material strength and water washability, thereby improving the overall performance of the polyurethane membrane material.

[0071] Example 2: The above-mentioned Example 1 introduces potassium phosphate in the preparation of modified porous biochar to form a synergistic activation system with potassium hydroxide, thereby solving the problems of traditional polyurethane membranes that it is difficult to balance moisture permeability and waterproofness, insufficient mechanical properties and poor durability, achieving efficient diffusion of water vapor and barrier of liquid water, enhancing interfacial bonding, improving material strength and water washability, thereby improving the comprehensive performance of the polyurethane membrane material. In order to further improve the comprehensive performance of the polyurethane membrane material, further improvements are made on the basis of Example 1.

[0072] The mixed material in the preparation of the porous biochar in step S1 further includes polyethylene glycol (PEG), the molecular weight of which is 4000, and the amount added is 20%-30% of the mass of potassium phosphate;

[0073] The ball milling time in step S1 is 40 min; and the heating rate of calcination is 3° C. / min.

[0074] The technical solution of this embodiment was tested on the basis of Experiment 3 of Example 1. The difference between this embodiment and Example 1 is that polyethylene glycol was further added, wherein the amount of polyethylene glycol added was 20% (Experiment 4), 30% (Experiment 5), and 25% (Experiment 6) of the mass of potassium phosphate, respectively. In addition, the ball milling time in step S1 was 40 minutes; the calcination heating rate was 3°C / min;

[0075] The highly waterproof and breathable polyurethane membrane materials prepared in Experiments 4 to 6 above were subjected to performance tests. The test results are shown in Table 2 below:

[0076] Table 2

[0077]

[0078] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0079] By introducing polyethylene glycol, the dispersion optimization and reduction synergy are achieved. Polyethylene glycol wraps potassium phosphate particles through hydrogen bonding, inhibits agglomeration, and improves mixing uniformity. At the same time, it decomposes at high temperature to generate reducing gas (CO / H2), which reacts with the decomposition product of potassium phosphate (K2O) to generate active K + , enhance the carbon skeleton etching ability, and also promote graphitization and further optimize the pore structure;

[0080] Polyethylene glycol is a nonionic surfactant. The hydroxyl groups (-OH) in its molecular chain form a hydrogen bond network with the surface of potassium phosphate particles, reducing the surface energy of the particles and thus inhibiting agglomeration. In addition, the long polyethylene glycol chain forms a physical barrier between particles, preventing particle contact and further reducing agglomeration through steric hindrance.

[0081] Polyethylene glycol decomposes under high temperature in the hydrothermal stage to generate reducing gases such as CO and H2, which react with the decomposition product of potassium phosphate (K2O) to generate active K + , active K + Enhance the etching ability of the carbon skeleton to form denser micropores (0.5-2nm). At the same time, the reducing gas promotes the graphitization of the carbon layer to form a more regular microporous structure, thereby improving the stability of the structure;

[0082] The introduction of polyethylene glycol has the following effects on improving the performance of polyurethane membrane materials:

[0083] The moisture permeability is improved. After the polyethylene glycol is optimized and dispersed, the hierarchical pore connectivity of the modified porous biochar is optimized, the connectivity of the hierarchical pores (micropore-dominated + mesopore-assisted) is enhanced, the water vapor diffusion resistance is reduced, and the water vapor diffusion path is shortened;

[0084] The hydrostatic pressure resistance is enhanced, the pore size distribution of the modified porous biochar is uniform, and liquid water penetration requires greater pressure, while the superhydrophobic surface blocks liquid water;

[0085] The mechanical properties and durability are improved. The graphitized carbon skeleton (elastic modulus +15%) and covalent bond interface of the modified porous biochar jointly enhance the material's tensile strength and further improve the mechanical strength. The water washing retention rate is further improved. The stable pore structure can reduce water washing collapse, and the covalent bond combination reduces interface peeling.

[0086] Embodiment three: the above embodiment two solves the problems of mixture agglomeration, carbon skeleton etching and insufficient optimization of pore structure by introducing polyethylene glycol in the preparation of modified porous biochar. Polyethylene glycol realizes dispersion optimization and reduction coordination, inhibits agglomeration, enhances etching and promotes graphitization, thereby improving the moisture permeability, hydrostatic pressure resistance, mechanical properties and water pressure retention rate after washing of the polyurethane membrane material, and enhancing the comprehensive performance of the material. Further improvement is made on the basis of embodiment two to further improve the comprehensive performance of the polyurethane membrane material.

[0087] The potassium phosphate includes coarse-grained potassium phosphate 5μm and fine-grained potassium phosphate 3μm; the mass ratio of fine-grained and coarse-grained is 7:3;

[0088] The coarse and fine-grained potassium phosphate is added in sections, fine-grained potassium phosphate is first added and premixed with polyethylene glycol, and then coarse-grained potassium phosphate is added in the middle of the reaction;

[0089] The sectioned addition is specifically:

[0090] In step S1, corn straw powder, urea, cetyl ammonium bromide, fine-grained potassium phosphate and polyethylene glycol are mixed and ball milled to obtain a mixture;

[0091] The ball milling time is 40 min and the rotation speed is 400 rpm;

[0092] In the middle of the reaction, i.e. after 1 h of hydrothermal reaction, coarse-grained potassium phosphate is added into the reaction system with ultrasonic-assisted dispersion, and the reaction continues;

[0093] The ultrasonic frequency is 40 kHz and the power is 300 W.

[0094] The technical scheme of this embodiment is based on the experiment of embodiment two. The difference between the experiment of this embodiment and the experiment of embodiment two is that the potassium phosphate includes coarse-grained potassium phosphate 5μm and fine-grained potassium phosphate 3μm, and the mass ratio of fine-grained and coarse-grained is 7:3. In addition, in step S1, coarse and fine-grained potassium phosphate is added in sections, fine-grained is first added and premixed with polyethylene glycol, and coarse-grained potassium phosphate is added in the middle of the reaction. The polyethylene glycol addition amount is 20% (experiment seven), 30% (experiment eight) and 25% (experiment nine) of the mass of potassium phosphate, respectively.

[0095] The high waterproof and moisture-permeable polyurethane membrane materials prepared in experiments four to six are tested for performance, and the test results are shown in Table 3.

[0096] Table 3

[0097]

[0098] The technical scheme in the above embodiments of the present application has at least the following technical effects or advantages:

[0099] By adding different particle sizes of potassium phosphate in stages and combining with the dynamic dispersion technology of polyethylene glycol, the microstructure is further optimized. By multi-scale potassium phosphate synergistic etching of biochar, the fine particles (3 μm) are uniformly dispersed after pre-mixing with polyethylene glycol, and preferentially etch the carbon skeleton to form micropores (0.5-2 nm) to provide a rapid diffusion channel for water vapor; coarse particles (5 μm) are added in the middle stage, and the coarse particles are dispersed by ultrasonic assistance (40 kHz, 300 W) to build a mesoporous (2-50 nm) skeleton in the carbon skeleton as a water vapor buffer zone to reduce diffusion resistance;

[0100] By adding different particle sizes of potassium phosphate in stages, fine particles are preferentially wrapped by polyethylene glycol (hydrogen bond adsorption) to avoid collision and agglomeration with coarse particles, and the dispersion uniformity is improved by about 30%; coarse particles are added in the middle stage (after hydrothermal reaction for 1 h) with ultrasonic dispersion (40 kHz, 300 W), polyethylene glycol wraps fine particles in the early stage, and adsorbs coarse particles in the middle stage to maintain stable dispersion of particles. At the same time, cavitation effect is generated during ultrasonic assisted dispersion process, micro-bubbles generated by ultrasonic cavitation break, break the agglomeration of particles, avoid the blockage of pores caused by agglomeration, so that they are uniformly dispersed in the reaction system, optimize the pore distribution, and dynamically maintain the dispersion stability;

[0101] By complementary stacking to optimize the pore structure, fine particles (3 μm) are embedded in the fiber gap to fill macropores (> 50 nm), reduce invalid pores, and increase specific surface area, coarse particles (5 μm) form a mesoporous network to enhance the connectivity of the pore channel, and the porosity is further improved to about 45%;

[0102] By dynamic dispersion of potassium phosphate of different particle sizes combined with polyethylene glycol added in stages, the following effects and effects are achieved for the performance improvement of polyurethane membrane materials;

[0103] Moisture permeability is improved, and the hierarchical pore channel shortens the diffusion path, among which micropores dominate diffusion and mesopores assist buffering, and water vapor transmission efficiency is improved by 7.5%; surface hydrophilic modification, phosphate groups and residual hydroxyl groups of polyethylene glycol synergistically enhance water molecule adsorption;

[0104] Static water pressure resistance is improved, pore size distribution is concentrated and uniform, and coarse / fine particles synergistically etch to make the pore size concentrated in the range of 0.5-20 nm, so that liquid water needs higher pressure to penetrate, at the same time, a hydrophobic and hydrophilic gradient is formed, -CF3 groups cover the mesoporous surface, while the inner wall of the micropore remains hydrophilic, thereby realizing selective barrier;

[0105] Mechanical properties are enhanced, pore collapse is prevented, mesoporous skeleton supports microporous structure, and pore size change rate is further reduced after 20 times of water washing.

[0106] Embodiment four: the above embodiment three solves the problems of mixture agglomeration and insufficient pore structure optimization by using the dynamic dispersion technology of adding different particle sizes of potassium phosphate combined with polyethylene glycol in stages, realizes microstructure optimization, prevents agglomeration, improves dispersion uniformity, optimizes pore distribution, and improves the porosity by complementary packing, so that the moisture permeability, hydrostatic pressure resistance, mechanical properties and water pressure retention rate after washing of the polyurethane film material are further improved. Further improve the comprehensive performance of the polyurethane film material, further improve the comprehensive performance of the polyurethane film material on the basis of embodiment three.

[0107] The polyethylene glycol includes high molecular weight polyethylene glycol and low molecular weight polyethylene glycol, the high molecular weight is 6000, the low molecular weight is 2000, and the mass ratio of the high molecular weight polyethylene glycol to the low molecular weight polyethylene glycol is 3:2;

[0108] In the segmented addition, fine particle potassium phosphate and high molecular weight polyethylene glycol are first premixed, and then coarse particle potassium phosphate and low molecular weight polyethylene glycol are added in the middle of the reaction.

[0109] In step S1, corn straw powder, urea, cetyl ammonium bromide, fine particle potassium phosphate and PEG-6000 are premixed, and ball milling is performed at 450 rpm for 45 min.

[0110] In the middle of the reaction, i.e. after 1 h of hydrothermal reaction, coarse potassium phosphate and PEG-2000 are mixed, ultrasonic dispersion is performed at 50 kHz and 350 W for 15 min, and then added into the reaction system for continuous reaction.

[0111] Based on the technical scheme in embodiment three, experiment nine is carried out as experiment ten, and the difference between experiment ten and experiment nine is that the polyethylene glycol in the present scheme includes high molecular weight polyethylene glycol and low molecular weight polyethylene glycol, the high molecular weight is 6000, the low molecular weight is 2000, and the mass ratio of the high molecular weight polyethylene glycol to the low molecular weight polyethylene glycol is 3:2.

[0112] The high waterproof and moisture permeable polyurethane film material prepared in the above experiment ten is tested for performance, and the test results are as follows: moisture permeability (g / m 2 ·24h) is 23560, hydrostatic pressure resistance (mmH2O) is 17850, breaking strength (MPa) is 63.5, and water pressure retention rate after washing is 98.0.

[0113] The polyurethane film material is a double-layer structure including a bottom layer and a surface layer.

[0114] In the preparation of the modified porous biochar in the bottom layer, the potassium phosphate is a fine particle, and the polyethylene glycol is a high molecular weight polyethylene glycol; in the preparation of the modified porous biochar in the surface layer, the potassium phosphate is a coarse particle, and the polyethylene glycol is a low molecular weight polyethylene glycol.

[0115] The microporous bottom layer is prepared by scraping and pre-curing at 90 DEG C for 8 minutes during the preparation of the polyurethane film material;

[0116] Then the surface layer slurry is scraped on the pre-cured bottom layer and finally cured at 100 DEG C for 15 minutes to form the mesoporous surface layer.

[0117] Based on the experiment nine in the third embodiment, the technical solution is experimentally tested as experiment eleven. The difference between experiment eleven and experiment nine is that the polyurethane film material in the present solution is a double-layer structure including a bottom layer and a surface layer. In the preparation of the modified porous biochar of the bottom layer, the potassium phosphate is fine particles, and the polyethylene glycol is high molecular weight polyethylene glycol. In the preparation of the modified porous biochar of the surface layer, the potassium phosphate is coarse particles, and the polyethylene glycol is low molecular weight polyethylene glycol.

[0118] The high waterproof and moisture permeable polyurethane film material prepared in the above experiment eleven is tested for performance, and the test results are that the moisture permeability (g / m 2 ·24h) is 24780, the hydrostatic pressure resistance (mmH2O) is 18950, the breaking strength (MPa) is 64.7, and the water pressure retention rate after washing is 98.4.

[0119] In the preparation of the modified porous biochar in the surface layer, the ball milling speed is 400 rpm, and the time is 25 minutes; so that part of the potassium phosphate particles are not completely dispersed, and local aggregation is formed.

[0120] In the middle of the reaction, when the low molecular weight PEG-2000 and coarse particles of potassium phosphate are added by ultrasonic auxiliary dispersion, the ultrasonic frequency is 50 kHz, the power is 300 W, and the time is 15 minutes; the damage of cavitation effect to the aggregate is reduced.

[0121] Based on the experiment eleven, the technical solution is experimentally tested as experiment twelve. The difference between experiment twelve and experiment eleven is that in the preparation of the modified porous biochar in the surface layer, the ball milling speed is 400 rpm, and the time is 25 minutes, and in the middle of the reaction, the ultrasonic power is 300 W.

[0122] The high waterproof and moisture permeable polyurethane film material prepared in the above experiment twelve is tested for performance, and the test results are that the moisture permeability (g / m 2 ·24h) is 25530, the hydrostatic pressure resistance (mmH2O) is 18720, the breaking strength (MPa) is 65.2, and the water pressure retention rate after washing is 98.7.

[0123] The technical solution in the above embodiments of the present application has at least the following technical effects or advantages:

[0124] By the reverse combination of polyethylene glycol molecular weight and potassium phosphate particle size, the dispersion and etching process is optimized; wherein, low molecular weight PEG-2000 is combined with coarse particle potassium phosphate (5 μm), the short chain of low molecular weight has permeability, because the molecular chain of PEG-2000 is short and the viscosity is low, it can quickly penetrate the gap between coarse particles, ensure the uniform dispersion of potassium phosphate, avoid local aggregation, in addition, the short chain molecule carries potassium phosphate into the gap between biochar fibers, forms regular mesoporous (2-50 nm), prevents the blockage of large pores (> 50 nm), and improves the etching uniformity; high molecular weight PEG-6000 is combined with fine particle potassium phosphate (3 μm), the long chain of high molecular weight has obvious steric hindrance effect, because the molecular chain of PEG-6000 is long and has strong adsorption, it can wrap the fine particles by winding, thereby inhibiting the agglomeration of the fine particles due to high specific surface area, promoting the uniform dispersion of the fine particles, and preferentially etching biochar, thereby forming 0.5-2 nm micropores to provide a rapid diffusion channel for water vapor;

[0125] In addition, the dispersion process realizes a staged process in cooperation with a premixing stage (fine particles combined with PEG-6000), through 450 rpm ball milling for 45 min, it ensures that the fine particles are completely wrapped, and the intermediate dispersion (coarse particles combined with PEG-2000) is through 50 kHz / 350 W ultrasonic for 15 min, which utilizes the cavitation effect to break the agglomeration of coarse particles and dynamically maintains the dispersion stability;

[0126] By the reverse combination of polyethylene glycol molecular weight and potassium phosphate particle size, the performance of the polyurethane membrane material is further improved;

[0127] The moisture permeability is significantly improved, wherein, the micropores dominate the diffusion, the fine particle etching forms uniform micropores (0.5-2 nm), the specific surface area increases (about to 1580 m² / g), and the water vapor diffusion path is shortened; the mesopores assist in buffering, the coarse particle etching constructs the mesoporous skeleton (2-50 nm), and the porosity is improved (about 48%), thereby reducing the diffusion resistance;

[0128] The hydrostatic pressure resistance is further improved, because the coarse / fine particle etching makes the pore size distribution concentrated, the liquid water penetration pressure is further improved, in addition, the mesoporous surface is covered by hydrophobic groups (-CF3), and the inner wall of the micropore remains hydrophilic, thereby realizing selective blocking of liquid water;

[0129] The mechanical properties are enhanced, the uniform dispersion of particles reduces stress concentration, the mesoporous skeleton supports the microporous structure, the anti-collapse ability is improved, the PEG molecular chain forms hydrogen bonds and physical entanglement with the polyurethane matrix, and the breaking strength is improved;

[0130] The water washing stability is optimized, the dispersion optimization reduces local defects, the particle and the matrix are more firmly combined, and the anti-washing off ability is enhanced.

[0131] By constructing a double-layer membrane structure, the functionality of each layer is improved while also enhancing the strengthening effect of interfacial bonding. The bottom layer (microporous layer) uses a combination of high-molecular-weight PEG-6000 and fine-particle potassium phosphate (3μm). Long-chain steric hindrance is used to inhibit fine particle aggregation, and 0.5-2nm micropores are etched to guide the rapid diffusion of water vapor. The surface layer (mesoporous layer) uses a combination of low-molecular-weight PEG-2000 and coarse-particle potassium phosphate (5μm). The short-chain permeability is used to optimize the dispersion of coarse particles, and 2-50nm mesopores are etched to block liquid water penetration.

[0132] During pre-curing of the base layer, some open pores are retained, allowing the surface slurry to penetrate and form a gradient transition interface, building a physical interpenetrating network and improving the bonding strength (interfacial bonding energy increases from 65kJ / mol to 68kJ / mol). The micropores (moisture permeability) and mesopores (water resistance) work together to overcome the contradiction between moisture permeability and water pressure resistance.

[0133] By constructing a double-layer membrane structure, the performance of the polyurethane membrane material is further improved;

[0134] Moisture permeability is significantly improved. The bottom layer is dominated by micropores, with the specific surface area of ​​micropores (0.5-2nm) increased to 1650m² / g, shortening the water vapor diffusion path. The surface layer is assisted by mesopores, with a porosity of 52% (2-50nm), reducing diffusion resistance.

[0135] The hydrostatic pressure resistance is improved, the surface mesopores are evenly distributed and concentrated, and the liquid water penetration pressure is increased; the surface hydrophobic groups block water, and the bottom hydrophilic micropores accelerate moisture removal, forming a hydrophobic and hydrophilic gradient;

[0136] The mechanical properties are enhanced, the surface mesopores (2-50nm) skeleton supports the underlying micropores, the anti-collapse ability is improved, the gradient transition interface reduces stress concentration, realizes interface strengthening, and improves fracture strength;

[0137] The water washing stability is optimized, and the particle-matrix bond is stronger due to the tight interface bonding and the physical interpenetrating network reducing the risk of delamination.

[0138] By adjusting the ball milling and ultrasonic process parameters during the preparation of modified porous biochar in the surface layer, the local aggregation of potassium phosphate particles is induced to form partial aggregates, thereby achieving partial pore expansion of the surface polyurethane membrane material.

[0139] Shortening the ball milling time (25 min) resulted in incomplete dispersion of coarse potassium phosphate particles (5 μm), with some particles existing as physical aggregates (10-20 μm in diameter). The interparticle spacing within the aggregates decreased, resulting in macropores (50-200 nm) during etching, while well-dispersed particles formed mesopores (2-50 nm). Furthermore, by reducing the ultrasonic power (300 W), the cavitation effect was weakened, avoiding complete breakup of the aggregates and retaining some controllable aggregates. Although the ultrasonic energy was insufficient to completely disperse the particles, it was sufficient to activate the adsorption of the PEG-2000 molecular chains, maintaining aggregate stability.

[0140] The existence of some aggregates forms an etching difference mechanism, and the aggregated potassium phosphate particles release K in a concentrated manner during the reaction. + and PO4 3- Therefore, the local etching intensity of the aggregate part is improved to form 50-200nm macropores, and the remaining evenly dispersed potassium phosphate is etched to form 2-50nm mesopores, thereby maintaining the water pressure resistance;

[0141] By inducing the local aggregation of potassium phosphate particles to form partial aggregates, the performance of the polyurethane membrane material is further improved;

[0142] The air permeability is significantly improved. The macropores formed in the aggregate part serve as fast channels. The 50-200nm macropores allow air to penetrate quickly, making it suitable for scenarios with high air permeability requirements (such as medical protective clothing). The macropores and mesopores form a gradient interconnected structure, optimizing the diffusion path and reducing the water vapor diffusion resistance.

[0143] The water pressure resistance is slightly reduced, and the 2-50nm mesopores formed by dispersed particles are still dominant (accounting for >80%), maintaining high water pressure resistance. The 0.5-2nm micropores in the bottom layer block liquid water penetration, compensating for the pressure resistance loss of the surface macropores;

[0144] Mechanical properties are enhanced, and the macropore area disperses external impact energy, forming stress dispersion and reducing the risk of crack propagation. In addition, the macropores and the underlying micropores are connected through a physical interpenetrating network, and the interface bonding energy is maintained at 68kJ / mol;

[0145] By adjusting the ratio of aggregates, the air permeability and water pressure resistance are balanced, and controllable adjustment of the air permeability and water pressure resistance can be achieved.

[0146] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A highly waterproof and breathable polyurethane film material, characterized in that: The raw materials include, by weight: 70 parts of polyether diol, 45 parts of diisocyanate, 45 parts of organic solvent, 12 parts of modified porous biochar, 6 parts of modified diatomaceous earth, 8 parts of chain extender, 2.5 parts of thickener, 1.5 parts of defoamer, 0.15 parts of UV absorber, and 0.08 parts of dibutyltin dilaurate; The preparation of the modified porous biochar comprises the following steps: S1. Corn straw powder, urea, cetyl ammonium bromide, potassium phosphate, and polyethylene glycol were mixed and ball-milled, and then subjected to a hydrothermal reaction, calcined with potassium hydroxide, and acid-washed to produce porous biochar; The potassium phosphate comprises fine particles with a particle size of 3 μm and coarse particles with a particle size of 5 μm, and the mass ratio of the fine particles to the coarse particles is 7:3; the polyethylene glycol comprises high molecular weight polyethylene glycol with a molecular weight of 6000 and low molecular weight polyethylene glycol with a molecular weight of 2000, and the mass ratio of the high molecular weight to the low molecular weight polyethylene glycol is 3:2; S2. thiolating the porous biochar with γ-mercaptopropyltrimethoxysilane to obtain thiol-modified porous biochar; S3. reacting the thiol-modified porous biochar with 2-(trifluoromethyl)acrylic acid under ultraviolet light to produce a thiol-ene reaction to obtain a modified porous biochar; The polyurethane film material has a double-layer structure, including a bottom layer and a surface layer; Wherein, the double-layer structure is formed by the following steps: (a) Base layer preparation: Modified porous biochar was prepared using fine-grained potassium phosphate and high-molecular-weight polyethylene glycol. The resulting slurry was then doctored and precured at 90°C for 8 min to form a microporous base layer. (b) Surface layer preparation: Modified porous biochar was prepared using coarse-grained potassium phosphate and low-molecular-weight polyethylene glycol. The resulting slurry was then applied to the pre-cured base layer and cured at 100°C for 15 min to form a mesoporous surface layer. When preparing the modified porous biochar in the surface layer, corn straw powder, urea, and cetyl ammonium bromide were premixed in step S1 and ball-milled at 400 rpm for 25 min; In the middle stage of the reaction, that is, after 1 h of hydrothermal reaction, low molecular weight PEG-2000 and coarse particle potassium phosphate were added by ultrasonic assisted dispersion with an ultrasonic frequency of 50 kHz, a power of 300 W and a time of 15 min.

2. The highly waterproof and moisture-permeable polyurethane membrane material according to claim 1, wherein: The mass ratio of corn straw powder to potassium phosphate is 70-80:5-8.

3. The highly waterproof and moisture-permeable polyurethane membrane material according to claim 1, wherein: The amount of polyethylene glycol added is 20%-30% of the mass of potassium phosphate.

4. The highly waterproof and moisture-permeable polyurethane membrane material according to claim 1, wherein: The preparation method of the highly waterproof and moisture-permeable polyurethane film material specifically comprises the following steps: Add polyether diol and organic solvent into a reactor, add diisocyanate, ultraviolet absorber and dibutyltin dilaurate under nitrogen protection, and stir to react at 65-75°C. When the content of NCO group reaches 7%, add chain extender, modified porous biochar, modified diatomaceous earth, defoamer and thickener, and continue to react for 1-2 hours. After the reaction is completed, pour it onto release paper, use a scraper to scrape out a thin film on the surface of the release paper, and then dry it in a 90-100°C oven to form a film to obtain the highly waterproof and moisture-permeable polyurethane membrane material.

5. A highly waterproof and breathable fabric, characterized in that: The polyurethane film material according to any one of claims 1 to 4 is compounded on the surface of a fabric substrate through a lamination or coating process.

Images