Highly waterproof and moisture permeable polyurethane film material and highly waterproof and moisture permeable fabric

Abstract

The invention discloses a highly waterproof and moisture permeable polyurethane film material and a highly waterproof and moisture permeable fabric, and relates to the technical field of polyurethane film materials. Comprising the following raw materials: polyether glycol, diisocyanate, an organic solvent, modified porous charcoal, modified diatomite, a chain extender, a thickening agent, a defoaming agent, an ultraviolet absorbent and dibutyltin dilaurate. The modified porous biochar is prepared by synergistically activating corn straw powder through potassium phosphate and potassium hydroxide, polyethylene glycol is added as a dispersing agent, and the modified porous biochar is subjected to sulfhydrylation and fluorination modification treatment; potassium phosphate is introduced in preparation of modified porous biochar of a polyurethane film material to cooperate with potassium hydroxide to form an activation system, and polyethylene glycol is combined to realize dispersion optimization and reduction cooperation, so that moisture permeability, water resistance, mechanical properties and durability of the material are improved.

Description

Technical Field

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

[0002] With the development of society and the continuous improvement of people's living quality, the demand for the functionality of clothing is increasing. Especially in sports clothing fabrics such as windbreakers, mountaineering clothes, and raincoats, they need to have good waterproof and moisture permeable properties. This not only requires preventing rain and snow from passing through the fabric, but also allowing the sweat excreted by the human body to transfer to the outside of the body in the form of water vapor through the fabric to ensure the wearing comfort. In recent years, waterproof and moisture permeable fabrics have developed rapidly, and their application fields are not only limited to military supplies and medical protection supplies, but are also rapidly expanding to the fields of outdoor leisure sports clothing and equipment.

[0003] For example, in the patent with the application number CN202411110081.0, a high-performance waterproof and moisture permeable polyurethane film material and its preparation method, the invention discloses a high-performance waterproof and moisture permeable polyurethane film material and its preparation method. By hydrothermal carbonization to prepare modified porous biochar and introducing diatomite to graft hydrophilic groups, although the moisture permeability and hydrostatic pressure resistance are improved to a certain extent, there are still problems such as the single potassium hydroxide activation system being prone to over-etching of the carbon skeleton, poor pore connectivity, easy collapse, weak interfacial bonding force, and the difficulty in balancing the liquid water barrier ability and moisture permeation efficiency in traditional polyurethane film materials. Summary of the Invention

[0004] In the embodiments of the present application, by providing a high waterproof and moisture permeable polyurethane film material and a high waterproof and moisture permeable fabric, by introducing potassium phosphate to cooperate with potassium hydroxide to form an activation system in the preparation of modified porous biochar of the polyurethane film material, and combining polyethylene glycol to achieve the coordination of dispersion optimization and reduction, the problems that the moisture permeability and waterproofness of traditional polyurethane films are difficult to balance, the mechanical properties are insufficient, and the durability is poor are solved, realizing the efficient diffusion of water vapor and the barrier of liquid water, enhancing the interfacial bonding force, and improving the material strength and washability, thereby improving the comprehensive performance of the polyurethane film material.

[0005] The embodiments of the present application provide a high waterproof and moisture permeable polyurethane film material, which includes the following raw materials 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 diatomite, 8 parts of chain extender, 2.5 parts of thickener, 1.5 parts of defoamer, 0.15 part of ultraviolet absorber, and 0.08 part of dibutyltin dilaurate; The preparation of the modified porous biochar includes the following steps: S1. Mix corn straw powder, urea, cetyltrimethylammonium bromide, potassium phosphate and polyethylene glycol, and perform ball milling. After hydrothermal reaction, conduct calcination with potassium hydroxide and pickling treatment to obtain porous biochar; S2. Perform thiolation reaction on the porous biochar with γ-mercaptopropyltrimethoxysilane to obtain thiolated porous biochar; S3. Under ultraviolet light, carry out a thiol-ene reaction between the thiolated porous biochar and 2-(trifluoromethyl)acrylic acid to obtain modified porous biochar.

[0006] Furthermore, the mass ratio of corn straw powder to potassium phosphate is 70 - 80:5 - 8.

[0007] Furthermore, the addition amount of polyethylene glycol is 20% - 30% of the mass of potassium phosphate.

[0008] Furthermore, 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 fine particles to coarse particles is 7:3.

[0009] Furthermore, 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 high molecular weight and low molecular weight polyethylene glycol is 3:2.

[0010] Furthermore, in step S1, after combining potassium phosphate with different particle sizes and polyethylene glycol with different molecular weights, they are added in segments. Specifically, first premix fine particle potassium phosphate and high molecular weight polyethylene glycol and then perform ball milling. Then, add coarse particle potassium phosphate and low molecular weight polyethylene glycol by ultrasonic dispersion in the middle stage of the reaction, that is, 1 h after the hydrothermal reaction.

[0011] Furthermore, the frequency of ultrasonic dispersion is 50 kHz, the power is 350 W, and the time is 15 min.

[0012] Furthermore, the polyurethane membrane material has a double-layer structure, including a bottom layer and a surface layer; Among them, when preparing the modified porous biochar in the bottom layer, potassium phosphate is fine particles and polyethylene glycol is high molecular weight polyethylene glycol; when preparing the modified porous biochar in the surface layer, potassium phosphate is coarse particles and polyethylene glycol is low molecular weight polyethylene glycol.

[0013] Furthermore, the preparation method of the high waterproof and moisture permeable polyurethane membrane material specifically includes the following steps: Add polyether diol and organic solvent into a reaction kettle. Under nitrogen protection, add diisocyanate, ultraviolet absorber, and dibutyltin dilaurate, and stir and react at 65 - 75 °C. When the content of NCO group reaches 7%, add chain extender, modified porous biochar, modified diatomite, defoamer, and thickener, and continue to react for 1 - 2 h. After the reaction is completed, pour it onto a release paper, and use a scraper to scrape out a film on the surface of the release paper. Then, dry it into a film in an oven at 90 - 100 °C to obtain the high waterproof and moisture permeable polyurethane film material.

[0014] A high waterproof and moisture permeable fabric is obtained by laminating or coating a polyurethane film material on the surface of a fabric substrate.

[0015] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: Firstly, by introducing potassium phosphate in the preparation of modified porous biochar, potassium phosphate and KOH cooperate to balance pore generation and structure stability. The hydrophilic-hydrophobic balanced surface enables selective passage of water vapor / liquid water, and at the same time, covalent bonds are used to strengthen the interfacial bonding, improving the material strength and washability, thereby enhancing the comprehensive performance of the polyurethane film material. Secondly, by introducing polyethylene glycol, the effects of dispersion optimization and reduction synergy are achieved. Polyethylene glycol wraps potassium phosphate particles through hydrogen bonding, inhibits agglomeration, and improves the mixing uniformity. At the same time, it decomposes to generate reducing gases at high temperature, which react with the decomposition products (K2O) of potassium phosphate to generate active K + , enhancing the carbon skeleton etching ability. In addition, it can also promote graphitization and further optimize the pore structure; Thirdly, by adding potassium phosphate with different particle sizes in stages and combining with the dynamic dispersion technology of polyethylene glycol, the microstructure is further optimized. The biochar is etched by potassium phosphate at multiple scales. Among them, the fine particles are premixed with polyethylene glycol and evenly dispersed at the initial stage, preferentially etching the carbon skeleton to form micropores, providing a rapid diffusion channel for water vapor; the coarse particles are added in the middle stage, and the coarse particles are dispersed by ultrasonic assistance to construct a mesoporous skeleton in the carbon skeleton as a water vapor buffer zone to reduce the diffusion resistance. Fourthly, through the reverse combination of the molecular weight of polyethylene glycol and the particle size of potassium phosphate, the dispersion and etching processes are optimized. Among them, the short-chain with low molecular weight has permeability. Since the PEG-2000 molecular chain is short and has low viscosity, it can quickly penetrate the gaps between coarse particles, ensuring the uniform dispersion of potassium phosphate and avoiding local aggregation. In addition, the short-chain molecules carry potassium phosphate deep into the gaps of biochar fibers to form regular mesopores, preventing the blockage of macropores and improving the etching uniformity. The long-chain with high molecular weight has an obvious steric hindrance effect. Since the PEG-6000 molecular chain is long and has strong adsorption, it can wrap fine particles by entanglement, thereby inhibiting the aggregation caused by its high specific surface area, promoting the uniform dispersion of fine particles, preferentially etching biochar, and thus forming micropores to provide a rapid diffusion channel for water vapor. Detailed implementation mode

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs. The terms used in the description of this invention herein are only for the purpose of describing specific implementation modes and are not intended to limit this invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0017] Example 1: A high waterproof and moisture permeable polyurethane film material, by weight, includes the following raw materials: 70 parts of polyether diol, 45 parts of diisocyanate, 45 parts of organic solvent, 12 parts of modified porous biochar, 6 parts of modified diatomite, 8 parts of chain extender, 2.5 parts of thickener, 1.5 parts of defoamer, 0.15 part of ultraviolet absorber, 0.08 part of dibutyltin dilaurate; Among them, the modified diatomite is obtained by treating with a silane coupling agent and then grafting with 2-acrylamido-2-methylpropanesulfonic acid; The preparation method of the modified porous biochar includes the following steps: S1. Mix corn straw powder, urea, cetyltrimethylammonium bromide, and potassium phosphate, and ball mill to obtain a mixed material; Disperse the mixed material in deionized water, stir to form a suspension, carry out hydrothermal reaction, under nitrogen protection, heat up and then keep warm to obtain a hydrothermal product; The hydrothermal product is washed and dried to obtain a solid product. The solid product is mixed with potassium hydroxide and calcined in a nitrogen atmosphere. After calcination, it is soaked in nitric acid solution, and then washed and dried to obtain porous biochar; Among them, the mass ratio of corn straw powder, deionized water, urea, cetyltrimethylammonium bromide, and potassium phosphate is 70-80:1000:40-50:5-10:5-8; the ball milling time is 30 min and the rotation speed is 300 rpm; Under nitrogen protection, the heating rate is 2 °C / min, and the temperature is raised to 200 - 210 °C, with a heat preservation reaction time of 5 - 6 h; The mass ratio of the solid product to potassium hydroxide is 20 - 30:12 - 18, the roasting temperature is 650 - 750 °C, the time is 2 - 3 h, and the heating rate is 5 °C / min; S2. Add the porous biochar into the ethanol aqueous solution, then add γ-mercaptopropyltrimethoxysilane, and carry out a stirring reaction. After the reaction is completed, filter, wash, and dry to obtain the mercapto-functionalized porous biochar; Among them, the mass ratio of the porous biochar to γ-mercaptopropyltrimethoxysilane is 20 - 30:2 - 4, the temperature of the stirring reaction is 60 - 70 °C, and the time is 1 - 2 h; S3. Add the mercapto-functionalized porous biochar into DMF, then add 2-(trifluoromethyl)acrylic acid and benzophenone, and carry out a thiol-ene reaction under ultraviolet light. After the reaction is completed, filter, wash, and dry to obtain the modified porous biochar; Among them, the mass ratio of the mercapto-functionalized porous biochar, 2-(trifluoromethyl)acrylic acid, and benzophenone is 20 - 30:1.4 - 2.8:0.1 - 0.2, the intensity of the ultraviolet light is 500 - 600 mW / cm 2 , the temperature of the thiol-ene reaction is 40 - 50 °C, and the time is 20 - 30 min.

[0018] The preparation method of the high waterproof and moisture permeable polyurethane film material specifically includes the following steps: Add polyether diol and organic solvent into the reaction kettle. Under nitrogen protection, add diisocyanate, ultraviolet absorber, and dibutyltin dilaurate, and stir and react at 65 - 75 °C. When the content of the NCO group reaches 7%, add the chain extender, modified porous biochar, modified diatomite, defoamer, and thickener, and continue to react for 1 - 2 h. After the reaction is completed, pour it onto the release paper, scrape out a film on the surface of the release paper with a scraper, and then dry it into a film in an oven at 90 - 100 °C to obtain the high waterproof and moisture permeable polyurethane film material.

[0019] Experiments were carried out on the technical solution of the above Example 1, divided into Experiment 1, Experiment 2, and Experiment 3. The only difference among Experiment 1, Experiment 2, and Experiment 3 is the dosage of potassium phosphate, and no potassium phosphate is added in the control group; The experiment includes the following raw materials by weight: 70 parts of polypropylene oxide 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 diatomite, 8 parts of ethylene glycol, 2.5 parts of polyurethane associative thickener, 1.5 parts of organosilicon polyether defoamer, 0.15 parts of UV-9, and 0.08 parts of dibutyltin dilaurate; The specific experimental parameters for the preparation of the modified porous biochar are as follows; Experiment 1: The mass ratio of corn stover powder, deionized water, urea, cetyltrimethylammonium bromide, and potassium phosphate is 75:1000:45:8:5; Experiment 2: The mass ratio of corn stover powder, deionized water, urea, cetyltrimethylammonium bromide, and potassium phosphate is 75:1000:45:8:8; Experiment 3: The mass ratio of corn stover powder, deionized water, urea, cetyltrimethylammonium bromide, and potassium phosphate is 75:1000:45:8:6.5; In step S1, under nitrogen protection, the heating rate is 2 °C / min, and the temperature is raised to 205 °C, and the holding reaction time is 5.5 h; The mass ratio of the solid product to potassium hydroxide is 25:15; the calcination temperature is 720 °C, the time is 2.5 h, and the heating rate is 5 °C / min; After the calcination is completed, the product is immersed in 10 wt% nitric acid for 1.5 h, centrifuged and washed until neutral, and dried to obtain porous biochar; In step S2, the mass ratio of the porous biochar to γ-mercaptopropyltrimethoxysilane is 25:3, and the reaction is carried out at 65 °C for 1.5 h in ethanol / water with a mass ratio of 8:2; In step S3, the mass ratio of the mercapto-functionalized 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 , and the temperature of the thiol-ene reaction is 45 °C and the time is 25 min; Preparation of the high waterproof and moisture permeable polyurethane film material: Weigh the raw materials according to the above formula, add polypropylene glycol ether diol with a molecular weight of 3000 and ethyl acetate to the reaction kettle. Under nitrogen protection, add isophorone diisocyanate, UV-9, and dibutyltin dilaurate, and stir and react at 70 °C. When the content of the NCO group reaches 7%, add ethylene glycol, modified porous biochar, diatomite, organosilicon polyether defoamer, and polyurethane associative thickener, and continue to react for 1.5 h. After the reaction is completed, pour it onto the release paper, scrape out a film on the surface of the release paper with a scraper, and then dry it into a film in an oven at 95 °C to obtain the high waterproof and moisture permeable polyurethane film material.

[0020] Perform performance tests on the high waterproof and moisture permeable polyurethane film materials prepared in the above comparative example and Experiments 1 to 3. Among them, the breaking strength and elongation at break are tested with reference to GB / T 3923.1-2013 "Textiles - Tensile properties of fabrics - Part 1: Determination of breaking force and elongation at break (strip method)"; The moisture permeability is tested with reference to GB / T 12704.2-2009 "Textiles - Test method for moisture permeability of fabrics - Part 2: Evaporation method"; The hydrostatic pressure resistance was tested according to GB / T 4744-2013 "Testing and Evaluation of Waterproof Performance of Textiles - Hydrostatic Pressure Method". For the test of the hydrostatic pressure retention rate after washing, the washing conditions were simulated as follows: 40°C, 15 min × 20 times. After centrifugal dehydration, the hydrostatic pressure resistance test was carried out again, and the hydrostatic pressure retention rate after washing was calculated. The results are shown in Table 1 below: Table 1

[0021] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: By introducing potassium phosphate, chemical activation synergy and interfacial bonding strengthening are realized, and the moisture permeability - waterproof balance and durability of the polyurethane film material are improved. First, potassium phosphate and potassium hydroxide form a synergistic activation system during high-temperature calcination. Among them, potassium phosphate decomposes into K2O and P2O5 during high-temperature hydrothermal and calcination processes. The decomposition products and potassium hydroxide jointly etch cellulose and lignin in corn straw to form a hierarchical porous structure (dominated by micropores and assisted by mesopores), realizing pore regulation. K2O, as an alkaline activator, jointly etches the carbon skeleton with potassium hydroxide to form micropores (about 0.5 - 2 nm), while P2O5 reacts with carbon to form pyrophosphate (K4P2O7), stabilizing the carbon layer structure at high temperature, forming a rigid skeleton, inhibiting carbon layer shrinkage, and thus inhibiting the collapse of pore walls, and the micropore retention rate is increased (about 60% - 85%); in addition, K + is inserted between carbon layers, expanding the layer spacing, forming more open pores, and the moisture permeability is increased by 12.2%; Secondly, phosphate (-PO4 3- ) modifies the surface of biochar through chemical bonding, enhancing its hydrophilicity, promoting the water vapor adsorption - desorption cycle. In subsequent mercapto (-SH) and fluorination (-CF3) modifications, the phosphate group and the hydrophobic group cooperate to form a gradient wetting surface (contact angle about 142°), blocking liquid water but allowing water vapor to pass through; Thirdly, the weak acidity of phosphate is complementary to the strong alkalinity of potassium hydroxide, avoiding the collapse of pore walls caused by excessive corrosion. The specific surface area is increased from 980 m 2 / g to about 1350 m 2 / g. At the same time, potassium phosphate can provide part of K + , thus reducing the dosage of potassium hydroxide, avoiding the decrease in pore connectivity caused by excessive corrosion of potassium hydroxide. Moreover, potassium phosphate, as a hard particle, promotes the uniform mixing of corn straw powder and activator during ball milling, reduces local agglomeration, and improves the activation efficiency; the phosphate group on the surface of biochar can also react with -NCO in polyurethane to form P - O - NH - covalent bonds, improving the compatibility between biochar and the matrix, enhancing the interfacial bonding force, increasing the fracture strength, and reducing washing peeling; The introduction of potassium phosphate has the following effects on improving the performance of polyurethane membrane materials: 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 the adsorption of water molecules and increase the moisture permeability; 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 cooperates with phosphate to block water droplet penetration. 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 to enhance interfacial bonding. At the same time, the mesopores (2-5nm) of porous biochar are embedded in the polyurethane molecular chains, which can resist water washing and stripping. By introducing potassium phosphate in the preparation of modified porous biochar, potassium phosphate and KOH work together to take into account both pore generation and structural stability. The hydrophilic-hydrophobic balanced surface achieves selective passage of water vapor / liquid water, while covalent bonds strengthen the interface bonding, improve material strength and water washability, and thus improve the comprehensive performance of the polyurethane membrane material.

[0022] 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 strength, and 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.

[0023] The mixed material in the preparation of the porous biochar in step S1 further includes polyethylene glycol (PEG), the molecular weight of the polyethylene glycol is 4000, and the addition amount is 20%-30% of the mass of potassium phosphate; The ball milling time in step S1 is 40 min; the heating rate of calcination is 3° C. / min.

[0024] The technical solution of this embodiment is experimented on the basis of Experiment 3 of Example 1. The difference between this embodiment and Example 1 is that polyethylene glycol is further added, wherein the amount of polyethylene glycol added is 20% (Experiment 4), 30% (Experiment 5) and 25% (Experiment 6) of the mass of potassium phosphate; in addition, the ball milling time in step S1 is 40 min; the heating rate of calcination is 3°C / min; The highly waterproof and breathable polyurethane membrane materials prepared in Experiments 4 to 6 above were subjected to performance tests, and the test results are shown in Table 2 below: Table 2

[0025] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: By introducing polyethylene glycol, the functions of dispersion optimization and reduction are synergistically achieved. Polyethylene glycol wraps potassium phosphate particles through hydrogen bonding, inhibits agglomeration, improves mixing uniformity, and at the same time decomposes at high temperature to generate reducing gases (CO / H2), which react with the decomposition products (K2O) of potassium phosphate to generate active K + , enhancing the carbon skeleton etching ability, and in addition, it can also promote graphitization and further optimize the pore structure; As a non-ionic surfactant, the hydroxyl groups (-OH) in the molecular chain of polyethylene glycol form a hydrogen bond network with the surface of potassium phosphate particles, reducing the surface energy of the particles, thereby inhibiting agglomeration. In addition, the long chains of polyethylene glycol form a physical barrier between the particles, preventing the particles from contacting, and further reducing agglomeration through steric hindrance effects; Polyethylene glycol decomposes at high temperature in the hydrothermal stage to generate reducing gases such as CO and H2, which react with the decomposition products (K2O) of potassium phosphate to generate active K + , active K + enhances the etching ability of the carbon skeleton, forms denser micropores (0.5 - 2 nm), and at the same time the reducing gas promotes the graphitization of the carbon layer, forming a more regular microporous structure, thereby improving the stability of the structure; By introducing polyethylene glycol, the following functions and effects are achieved for the performance improvement of polyurethane membrane materials: The moisture permeability is improved. After the dispersion of polyethylene glycol is optimized, the hierarchical pore connectivity of the modified porous biochar is optimized, the connectivity of the hierarchical pores (dominated by micropores + assisted by mesopores) is enhanced, the water vapor diffusion resistance is reduced, and the water vapor diffusion path is shortened; The hydrostatic pressure resistance is enhanced. The pore size distribution of the modified porous biochar is uniform, and a greater pressure is required for the penetration of liquid water. At the same time, the superhydrophobic surface blocks liquid water; The mechanical properties and durability are improved. The graphitized carbon skeleton (elastic modulus + 15%) of the modified porous biochar and the covalent bond interface together enhance the tensile resistance of the material, further improving the mechanical strength; the washing retention rate is further improved. The stable pore structure can reduce the collapse during washing, and the covalent bond combination reduces the interfacial peeling.

[0026] Example 3: In Example 2 above, by introducing polyethylene glycol in the preparation of modified porous biochar, the problems of agglomeration of the mixed materials, insufficient carbon skeleton etching, and pore structure optimization are solved. Polyethylene glycol realizes the synergy of dispersion optimization and reduction, inhibits agglomeration, enhances etching, and promotes graphitization, thereby improving the moisture permeability, hydrostatic pressure resistance, mechanical properties, and hydrostatic pressure retention rate after washing of the polyurethane membrane material, enhancing the comprehensive performance of the material. To further improve the comprehensive performance of the polyurethane membrane material, further improvements are made on the basis of Example 2.

[0027] The potassium phosphate includes coarse-grained potassium phosphate of 5 μm and fine-grained potassium phosphate of 3 μm; the mass ratio of the fine grains to the coarse grains is 7:3; The coarse and fine-grained potassium phosphate is added in segments. First, the fine-grained potassium phosphate is premixed with polyethylene glycol, and then the coarse-grained potassium phosphate is added in the middle stage of the reaction; The addition in segments is specifically as follows: In step S1, corn straw powder, urea, cetyltrimethylammonium bromide, fine-grained potassium phosphate, and polyethylene glycol are mixed and ball-milled to obtain a mixed material; Among them, the ball-milling time is 40 min and the rotation speed is 400 rpm; In the middle stage of the reaction, that is, after 1 h of hydrothermal reaction, the coarse-grained potassium phosphate is added to the reaction system by ultrasonic-assisted dispersion, and the reaction continues; Among them, the ultrasonic frequency is 40 kHz and the power is 300 W.

[0028] Experiments are carried out on the technical solution of this embodiment on the basis of the experiments in Example 2. The differences between the experiments in this embodiment and the experiments in Example 2 are that the potassium phosphate includes coarse-grained potassium phosphate of 5 μm and fine-grained potassium phosphate of 3 μm, and the mass ratio of the fine grains to the coarse grains is 7:3; in addition, the coarse and fine-grained potassium phosphate is added in segments in step S1. First, the fine grains are premixed with polyethylene glycol, and the coarse-grained potassium phosphate is added in the middle stage of the reaction; among them, the addition amounts of polyethylene glycol are 20% (Experiment 7), 30% (Experiment 8), and 25% (Experiment 9) of the mass of potassium phosphate respectively; The high waterproof and moisture permeable polyurethane membrane materials prepared in Experiments 4 to 6 above are subjected to performance tests, and the test results are shown in Table 3 below: Table 3

[0029] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: Through the dynamic dispersion technology of adding potassium phosphate with different particle sizes in stages and combining with polyethylene glycol, the further optimization of the microstructure is achieved. Through the multi-scale potassium phosphate synergistically etching biochar, among which, the fine particles (3μm) are premixed with polyethylene glycol at the initial stage and uniformly dispersed, preferentially etching the carbon skeleton to form micropores (0.5 - 2nm), providing a rapid diffusion channel for water vapor; the coarse particles (5μm) are added in the middle stage, and the coarse particles are dispersed by ultrasonic assistance (40kHz, 300W), constructing mesoporous (2 - 50nm) skeletons in the carbon skeleton as water vapor buffer zones to reduce the diffusion resistance; By adding potassium phosphate with different particle sizes in stages to prevent agglomeration, the fine particles are preferentially wrapped by polyethylene glycol (hydrogen bond adsorption), avoiding collision and agglomeration with the coarse particles, and the dispersion uniformity is improved by about 30%; the coarse particles are dispersed and added by ultrasonic (40kHz, 300W) in the middle stage of the reaction (after 1h of hydrothermal treatment). Polyethylene glycol wraps the fine particles at the initial stage and adsorbs the coarse particles in the middle stage to maintain the stable dispersion of the particles. At the same time, cavitation effects are generated during the ultrasonic-assisted dispersion process. The microbubbles generated by ultrasonic cavitation break, breaking the particle agglomeration and preventing their agglomeration from blocking the pores, so that they are uniformly dispersed in the reaction system, optimizing the pore distribution and dynamically maintaining the dispersion stability; The pore structure is optimized by complementary packing. The fine particles (3μm) are embedded in the fiber gaps to fill the macropores (>50nm), reducing the ineffective pores and increasing the specific surface area. The coarse particles (5μm) form a mesoporous network, enhancing the pore connectivity, and the porosity is further increased to about 45%; Through the dynamic dispersion of adding potassium phosphate with different particle sizes in stages and combining with polyethylene glycol, it has the following functions and effects on the performance improvement of polyurethane membrane materials; The moisture permeability is improved. The hierarchical pore channels shorten the diffusion path. Among them, the micropores dominate the diffusion and the mesopores assist in buffering, and the water vapor transmission efficiency is increased by 7.5%; the surface is hydrophilically modified, and the phosphate groups and the residual hydroxyl groups of polyethylene glycol synergistically enhance the water molecule adsorption; The hydrostatic pressure resistance is improved. The pore size distribution is concentrated and uniform. The synergistic etching of the coarse / fine particles makes the pore size concentrated in the range of 0.5 - 20nm, so that liquid water needs a higher pressure to penetrate. At the same time, a hydrophobic and hydrophilic gradient is formed. The -CF3 groups cover the surface of the mesopores, while the inner wall of the micropores remains hydrophilic, thus achieving selective barrier; The mechanical properties are enhanced. The pores resist collapse, and the mesoporous skeletons support the microporous structure, and the pore size change rate is further reduced after 20 times of washing.

[0030] Example 4: In Example 3 above, through the dynamic dispersion technology of adding potassium phosphate with different particle sizes in stages and combining with polyethylene glycol, the problems of agglomeration of the mixed materials and insufficient optimization of the pore structure are solved, the microstructure is optimized, agglomeration is prevented, the dispersion uniformity is improved, and the pore distribution is optimized; complementary packing improves the porosity, further enhancing the moisture permeability, hydrostatic pressure resistance, mechanical properties, and the retention rate of hydrostatic pressure resistance after washing of the polyurethane membrane material. To further improve the comprehensive performance of the polyurethane membrane material, it is further improved on the basis of Example 3.

[0031] 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 high-molecular-weight and low-molecular-weight polyethylene glycol is 3:2. In the staged addition, fine particle potassium phosphate is first added and premixed with high-polymer polyethylene glycol, and then coarse particle potassium phosphate and low-molecular-weight polyethylene glycol are added in the middle stage of the reaction. Specifically: In step S1, corn straw powder, urea, cetyltrimethylammonium bromide, fine particle potassium phosphate, and PEG-6000 are premixed and ball milled at 450 rpm for 45 min. In the middle stage of the reaction, that is, after 1 h of hydrothermal reaction, coarse potassium phosphate and PEG-2000 are mixed, ultrasonically dispersed at 50 kHz and 350 W for 15 min, then added to the reaction system, and the reaction continues.

[0032] Experiments were carried out on the basis of Experiment 9 in Example 3 for this technical solution. As Experiment 10, the difference between Experiment 10 and Experiment 9 is that in this solution, 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 high-molecular-weight and low-molecular-weight polyethylene glycol is 3:2. The high-waterproof and moisture-permeable polyurethane membrane material prepared in Experiment 10 above was subjected to performance testing. The test results were as follows: the moisture permeability (g / m 2 ·24 h) was 23560, the hydrostatic pressure resistance (mmH2O) was 17850, the breaking strength (MPa) was 63.5, and the retention rate of hydrostatic pressure resistance after washing was 98.0.

[0033] The polyurethane membrane material is a double-layer structure including a bottom layer and a surface layer; Among them, when preparing the modified porous biochar in the bottom layer, potassium phosphate is fine particles and polyethylene glycol is high-molecular-weight polyethylene glycol; when preparing the modified porous biochar in the surface layer, potassium phosphate is coarse particles and polyethylene glycol is low-molecular-weight polyethylene glycol; When preparing the bottom layer of the polyurethane membrane material, after scraping, it is pre-cured at 90 °C for 8 min to form a microporous bottom layer; Then the surface layer slurry is scraped on the pre-cured bottom layer and finally cured at 100 °C for 15 min to form a mesoporous surface layer.

[0034] Based on Experiment 9 in Embodiment 3, an experiment was conducted on this technical solution. As Experiment 11, the difference between Experiment 11 and Experiment 9 is that the polyurethane film material in this solution is a double-layer structure including a bottom layer and a surface layer. In the preparation of the modified porous biochar in the bottom layer, potassium phosphate is in fine particles and polyethylene glycol is high molecular weight polyethylene glycol. In the preparation of the modified porous biochar in the surface layer, potassium phosphate is in coarse particles and polyethylene glycol is low molecular weight polyethylene glycol; The high waterproof and moisture-permeable polyurethane film material prepared in Experiment 11 above was subjected to performance testing. The test results were as follows: the moisture permeability (g / m 2 ·24h) was 24780, the hydrostatic pressure resistance (mmH2O) was 18950, the breaking strength (MPa) was 64.7, and the retention rate of hydrostatic pressure resistance after washing was 98.4.

[0035] When preparing the modified porous biochar in the surface layer, the ball milling speed was 400 rpm and the time was 25 min; part of the potassium phosphate particles were not completely dispersed, forming local aggregates; In the middle stage of the reaction, when adding low molecular weight PEG-2000 and coarse particle potassium phosphate under ultrasonic assistance, the ultrasonic frequency was 50 kHz, the power was 300 W, and the time was 15 min; reducing the damage of cavitation effect to the aggregates; Based on Experiment 11, an experiment was conducted on this technical solution. As Experiment 12, the difference between Experiment 12 and Experiment 11 is that when preparing the modified porous biochar in the surface layer, the ball milling speed was 400 rpm and the time was 25 min, and in the middle stage of the reaction, the ultrasonic power was 300 W; The high waterproof and moisture-permeable polyurethane film material prepared in Experiment 12 above was subjected to performance testing. The test results were as follows: the moisture permeability (g / m 2 ·24h) was 25530, the hydrostatic pressure resistance (mmH2O) was 18720, the breaking strength (MPa) was 65.2, and the retention rate of hydrostatic pressure resistance after washing was 98.7.

[0036] The technical solutions in the embodiments of the present application above have at least the following technical effects or advantages: Optimize the dispersion and etching processes through the reverse combination of the molecular weight of polyethylene glycol and the particle size of potassium phosphate. Among them, low-molecular-weight PEG-2000 binds to coarse-grained potassium phosphate (5 μm). The short-chain of low molecular weight has permeability. Since the PEG-2000 molecular chain is short and has low viscosity, it can quickly penetrate the gaps between coarse particles, ensuring the uniform dispersion of potassium phosphate and avoiding local aggregation. In addition, the short-chain molecules carry potassium phosphate deep into the gaps of biochar fibers to form regular mesopores (2 - 50 nm), preventing the blockage of macropores (>50 nm) and improving the etching uniformity. High-molecular-weight PEG-6000 binds to fine-grained potassium phosphate (3 μm). The long-chain of high molecular weight has an obvious steric hindrance effect. Since the PEG-6000 molecular chain is long and has strong adsorption, it can wrap the fine particles by entanglement, thereby inhibiting the aggregation caused by its high specific surface area, promoting the uniform dispersion of fine particles, preferentially etching biochar, and thus forming 0.5 - 2 nm micropores to provide a rapid diffusion channel for water vapor. In addition, in the dispersion process, a staged process is implemented to synergistically pre-mix the stage (fine particles combined with PEG-6000). Through ball milling at 450 rpm for 45 min, ensure that the fine particles are completely wrapped. The medium-term dispersion (coarse particles combined with PEG-2000) is carried out by ultrasonic waves at 50 kHz / 350 W for 15 min. Utilize the cavitation effect to break the aggregation of coarse particles and dynamically maintain the dispersion stability. Through the reverse combination of the molecular weight of polyethylene glycol and the particle size of potassium phosphate, the performance of the polyurethane membrane material is further improved. The moisture permeability is significantly improved. Among them, micropores dominate the diffusion. The fine particles are etched to form uniform micropores (0.5 - 2 nm), the specific surface area increases (about increased to 1580 m² / g), and the water vapor diffusion path is shortened. Mesopores assist in caching. The coarse particles are etched to construct a mesoporous framework (2 - 50 nm), and the porosity is increased (about 48%), thereby reducing the diffusion resistance. The hydrostatic pressure resistance is further improved. Since the combined etching of coarse / fine particles makes the pore size distribution concentrated, the liquid water penetration pressure is further increased. In addition, the mesoporous surface is covered by hydrophobic groups (-CF3), and the inner wall of the micropores retains hydrophilicity, thus achieving selective blocking of liquid water. The mechanical properties are enhanced. The uniform dispersion of particles reduces stress concentration. The mesoporous framework supports the microporous structure, and the anti-collapse ability is improved. The PEG molecular chain forms hydrogen bonds and physical entanglements with the polyurethane matrix, and the fracture strength is increased. The washing stability is optimized. The optimized dispersion reduces local defects, the particles are more firmly combined with the matrix, and the anti-washing-off ability is enhanced.

[0037] By constructing a double-layer membrane structure, the functionality of each layer is improved while the strengthening effect of the interface bonding is improved. The bottom layer (microporous layer) uses a combination of high molecular weight PEG-6000 and fine-particle potassium phosphate (3μm). The long-chain steric hindrance is used to inhibit the agglomeration of fine particles, and 0.5-2nm micropores are etched to dominate 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 the penetration of liquid water. When the bottom layer is pre-cured, some open pores are retained, and the surface slurry penetrates to form a gradient transition interface, constructing a physical interpenetrating network, improving the bonding strength (interface bonding energy is increased from 65kJ / mol to 68kJ / mol), and the micropores (moisture permeability) and mesopores (water blocking) work together to break the contradiction between moisture permeability and water pressure resistance. By constructing a double-layer membrane structure, the performance of the polyurethane membrane material is further improved; The moisture permeability is significantly improved. The bottom layer is dominated by micropores. The specific surface area of ​​micropores (0.5-2nm) increases to 1650m² / g, shortening the water vapor diffusion path. The surface mesopores are auxiliary, and the porosity of mesopores (2-50nm) is 52%, reducing the diffusion resistance. 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 discharge, forming a hydrophobic and hydrophilic gradient; The mechanical properties are enhanced, the surface mesopores (2-50nm) skeleton supports the bottom micropores, the anti-collapse ability is improved, the gradient transition interface reduces stress concentration, realizes interface strengthening, and improves fracture strength; 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.

[0038] 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; The ball milling time was shortened (25 min), so that the coarse potassium phosphate particles (5 μm) were not completely dispersed, and some particles existed in the form of physical agglomerates (particle size 10-20 μm). The distance between particles inside the agglomerates was reduced, and macropores (50-200 nm) were formed during etching, while well-dispersed particles formed mesopores (2-50 nm). In addition, by reducing the ultrasonic power (300 W), the intensity of the cavitation effect was weakened, the agglomerates were avoided from being completely broken, and some controllable aggregates were retained. Although the ultrasonic energy was not enough to completely disperse the particles, it was enough to activate the adsorption of the PEG-2000 molecular chain and maintain the stability of the aggregates. The existence of partial aggregates forms an etching difference mechanism. The aggregated potassium phosphate particles release K concentratedly during the reaction. + and PO4 3- , so the local etching intensity of the aggregate part is increased, forming macropores of 50 - 200 nm. The remaining uniformly dispersed potassium phosphate is etched to form mesopores of 2 - 50 nm, thus maintaining the hydrostatic pressure resistance performance. By inducing local aggregation of potassium phosphate particles to form partial aggregates, the performance of the polyurethane membrane material is further improved. The air permeability is significantly improved. The macropores formed by the aggregate part serve as fast channels. The 50 - 200 nm macropores allow air to penetrate quickly, which is suitable for scenarios with high air permeability requirements (such as medical protective clothing). The macropores and mesopores form a gradient-connected structure, optimizing the diffusion path and reducing the water vapor diffusion resistance. The hydrostatic pressure resistance is slightly reduced. The 2 - 50 nm mesopores formed by the dispersed particles still dominate (accounting for > 80%), maintaining high hydrostatic pressure resistance. The 0.5 - 2 nm micropores at the bottom layer block the penetration of liquid water, compensating for the loss of pressure resistance of the surface macropores. The mechanical properties are enhanced. The macropore region disperses external impact energy, forming stress dispersion and reducing the risk of crack propagation. In addition, the macropores and the bottom micropores are combined through a physical interpenetrating network, and the interfacial binding energy is maintained at 68 kJ / mol. By adjusting the aggregate ratio, the air permeability and hydrostatic pressure resistance are balanced, realizing the controllable adjustment of air permeability and hydrostatic pressure resistance.

[0039] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high waterproof and moisture permeable polyurethane film material, characterized in that, By weight, it includes the following raw materials: 70 parts of polyether diol, 45 parts of diisocyanate, 45 parts of organic solvent, 12 parts of modified porous biochar, 6 parts of modified diatomite, 8 parts of chain extender, 2.5 parts of thickener, 1.5 parts of defoamer, 0.15 part of ultraviolet absorber, and 0.08 part of dibutyltin dilaurate; The preparation of the modified porous biochar includes the following steps: S1. Mix corn straw powder, urea, cetyltrimethylammonium bromide, potassium phosphate, and polyethylene glycol and ball-mill them. After hydrothermal reaction, perform potassium hydroxide calcination and pickling treatment to obtain porous biochar; S2. Perform thiolation reaction on the porous biochar with γ-mercaptopropyltrimethoxysilane to obtain thiolated porous biochar; S3. Under ultraviolet light, perform a thiol-ene reaction between the thiolated porous biochar and 2-(trifluoromethyl)acrylic acid to obtain the modified porous biochar.

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

3. The high waterproof and moisture-permeable polyurethane film material according to claim 1, characterized in that, The addition amount of polyethylene glycol is 20%-30% of the mass of potassium phosphate.

4. The high waterproof and moisture permeable polyurethane film material according to claim 1, wherein, 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.

5. The high waterproof and moisture-permeable polyurethane film material according to claim 4, wherein, 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.

6. The high waterproof and moisture-permeable polyurethane film material according to claim 5, wherein In step S1, the potassium phosphate with different particle sizes and the polyethylene glycol with different molecular weights are combined and added in segments. Specifically, first premix the fine particle potassium phosphate and the high molecular weight polyethylene glycol and then ball-mill them. Then, add the coarse particle potassium phosphate and the low molecular weight polyethylene glycol in the middle stage of the reaction, that is, 1 h after the hydrothermal reaction, by ultrasonic dispersion.

7. The high waterproof and moisture-permeable polyurethane film material according to claim 6, characterized in that, The frequency of ultrasonic dispersion is 50 kHz, the power is 350 W, and the time is 15 min.

8. The high waterproof and moisture-permeable polyurethane film material according to claim 1, characterized in that The polyurethane film material has a double-layer structure, including a bottom layer and a surface layer; Among them, when preparing the modified porous biochar in the bottom layer, the potassium phosphate is fine particles and the polyethylene glycol is high molecular weight polyethylene glycol; when preparing the modified porous biochar in the surface layer, the potassium phosphate is coarse particles and the polyethylene glycol is low molecular weight polyethylene glycol.

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

10. A highly waterproof and moisture-permeable fabric, characterized in that, The polyurethane film material described in any one of claims 1-9 is compounded on the surface of a fabric substrate by a lamination or coating process.

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