Nanofiber high moisture permeability and waterproof fabric with multi-level interconnected channels and preparation method thereof

Abstract

The present invention belongs to the field of preparation of nanofiber composite fabrics. The present invention provides a nanofiber high moisture permeability waterproof fabric with multi-level interconnected channels and a preparation method thereof. The fabric body includes an outer layer, an intermediate layer and an inner layer. The outer layer is a pure polyester waterproof fabric that has been waterproofed, the intermediate layer is a nanofiber membrane with multi-level interconnected channels, and the inner layer is a pure polyester fabric; the inner side of the outer layer of pure polyester waterproof fabric is bonded to the hydrophobic polyvinyl alcohol nanofiber membrane of the intermediate layer of nanofiber membrane with multi-level interconnected channels through hot melt adhesive compounding, and the inner layer of pure polyester fabric is bonded to the hydrophilic polyurethane nanofiber membrane of the intermediate layer of nanofiber membrane with multi-level interconnected channels through hot melt adhesive compounding. The nanofiber membrane with multi-level interconnected pores in the middle layer is composed of multiple nanofiber membrane layers stacked in sequence. Each nanofiber membrane layer has two layers of nanofiber membranes with different fiber diameters, one layer is a hydrophilic polyurethane nanofiber membrane, and the other layer is a hydrophobic polyvinyl alcohol nanofiber membrane. The nanofibers of the two membranes between and within the multi-level nanofiber membrane layers are cross-connected to form a three-dimensional structure with multi-level interconnected pores. The pore size gradually decreases from the hydrophilic polyurethane nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane. The moisture permeability is higher than 15000g / (m 2 24h), the hydrostatic pressure is higher than 60kPa.

Description

Technical Field

[0001] The invention relates to a nanofiber high moisture permeability and waterproof fabric with multi-level interconnected channels and a preparation method thereof, belonging to the field of nanofiber composite fabric preparation. Background Art

[0002] With the development of science and technology, people's living standards are constantly improving, and the requirements for the comfort and functionality of clothing fabrics are constantly increasing. Polyurethane coated fabrics, as the main fabric of jackets, have a good waterproof effect, but the moisture permeability is very poor and the comfort is low; PTFE membrane materials, as the inner layer structure of nanofiber jacket fabrics, have improved moisture permeability, but fluorine-containing materials are harmful to the human body and are gradually being banned. Chinese patent CN102632648A provides a high-efficiency waterproof and breathable fabric and a preparation method thereof. The preparation method of the electrospun nanofiber membrane is to add polyurethane to a solvent at room temperature, and then add hydrophobic nanoparticles or a spinning solution with uniform properties to perform electrospinning, obtain an electrospun nanofiber membrane on a receiving device, transfer the adhesive in a dotted form to the electrospun nanofiber membrane through a transfer roller to form an adhesive dot-shaped adhesive layer, and then adhere the fiber fabric to form a fiber fabric layer, and then perform hot rolling to make a high-efficiency waterproof and breathable fabric. The hydrophobic nanoparticles in the patent are polytetrafluoroethylene. The raw material perfluorooctanoic acid (PFOA) used in the production process is carcinogenic. Polytetrafluoroethylene is difficult to degrade in the environment, posing a potential environmental hazard. It is strictly regulated in the EU and is at risk of being banned. In addition, the moisture permeability of the patented high-efficiency waterproof and breathable fabric is only 6000-9000g / m 2 24h, relatively low. Summary of the Invention

[0003] In order to solve the deficiencies in the above-mentioned prior art, the present invention provides a nanofiber high moisture permeability and waterproof fabric with multi-level interconnected pores, the middle layer is a nanofiber membrane with multi-level interconnected pores, which is formed by stacking multiple nanofiber membrane layers in sequence, and each nanofiber membrane layer has two layers of nanofiber membranes with different fiber diameters, one layer is a hydrophilic polyurethane nanofiber membrane with a pore size range of 2 to 4 μm, and the other layer is a hydrophobic polyvinyl alcohol nanofiber membrane with a pore size range of 0.1 to 2 μm. The nanofibers of the two membranes in the membrane layer are cross-connected to form a three-dimensional structure with multi-level interconnected pores, and the pore size is determined by the hydrophilic polyurethane. The pore size gradually decreases from the nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane; the multi-level nanofiber membrane layer forms a "hydrophilic-hydrophobic-hydrophilic-hydrophobic" structure, which quickly transfers water vapor to the outside through the "adsorption-diffusion-desorption-adsorption-diffusion-desorption" method; at the same time, the pore size gradually decreases from the hydrophilic polyurethane nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane, thereby forming a capillary effect, which is beneficial to the volatilization of water vapor and increases the moisture permeability of the fabric; through isocyanate cross-linking, polyvinyl alcohol forms a hydrophobic, small-pore nanofiber membrane, which fits with the outer waterproof fabric to improve the waterproof effect of the fabric.

[0004] The technical solution of the present invention is a nanofiber high moisture permeability waterproof fabric with multi-level interconnected channels, comprising an outer layer, an intermediate layer and an inner layer. The outer layer is a pure polyester waterproof fabric with waterproof finishing. The yarn fineness of the fabric is 20-150D, the density is 500-1000T, and the gram weight is 100-250g / m 2 , hydrostatic pressure 2~10kPa; the middle layer is a nanofiber membrane with multi-level interconnected channels, which is composed of multi-level nanofiber membrane layers stacked in sequence. Each nanofiber membrane layer has two layers of nanofiber membranes with different fiber diameters, one layer is a hydrophilic polyurethane nanofiber membrane with a pore size range of 2~4um, and the other layer is a hydrophobic polyvinyl alcohol nanofiber membrane with a pore size range of 0.1~2um. The nanofibers of the two membranes in the membrane layer are cross-connected to form a three-dimensional structure with multi-level interconnected channels, and the pore size gradually decreases from the hydrophilic polyurethane nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane; the inner layer is pure polyester fabric with a yarn fineness of 10~100D and a gram weight of 30~60g / m 2 The inner side of the outer pure polyester waterproof fabric is bonded to the hydrophobic polyvinyl alcohol nanofiber membrane of the middle layer with multi-level interconnected pores through hot melt adhesive compounding, and the inner pure polyester fabric is bonded to the hydrophilic polyurethane nanofiber membrane of the middle layer with multi-level interconnected pores through hot melt adhesive compounding.

[0005] Preferably, the hydrophilic polyurethane nanofiber membrane has a gram weight of 0.5 to 20 g / m 2 , the fiber diameter ranges from 140 to 400 nm.

[0006] Preferably, the hydrophobic polyvinyl alcohol nanofiber membrane has a gram weight of 0.5 to 20 g / m2 , the fiber diameter ranges from 50 to 130 nm.

[0007] The present invention also provides a method for preparing a nanofiber high moisture permeability and waterproof fabric with multi-level interconnected pores, the steps of which are:

[0008] (1) preparing a silicone waterproofing agent finishing liquid with a concentration of 2-8% by weight, and performing waterproof finishing on the pure polyester fabric as the outer layer by a padding method, wherein the padding process is one dip and one padding, and drying at 100-150° C. for 10-20 minutes after the padding is completed to obtain the outer layer waterproof fabric;

[0009] (2) The nanofiber membranes are alternately stacked on the substrate by electrospinning, firstly loading a layer of hydrophilic polyurethane nanofiber membrane, and then loading a layer of hydrophobic polyvinyl alcohol nanofiber membrane, and the cycle is repeated multiple times to form a nanofiber membrane with multi-level interconnected pores; after the spinning is completed, the nanofiber membrane is cross-linked at 130-180°C for 2-20 minutes;

[0010] (3) The substrate of the nanofiber membrane with multi-level interconnected pores obtained in step (2) is compounded with the outer waterproof fabric obtained in step (1) by a hot melt adhesive compounding method, so that the inner side of the outer waterproof fabric and the hydrophobic polyvinyl alcohol nanofiber membrane of the nanofiber membrane with multi-level interconnected pores are adhered together. After the compounding is completed, the substrate is peeled off, and the nanofiber membrane with multi-level interconnected pores is transferred to the outer waterproof fabric;

[0011] (4) The outer layer waterproof fabric of the nanofiber membrane with multi-level interconnected pores is compounded with the inner layer fabric by hot melt adhesive compounding. After the compounding is completed, it is cured for 40 to 50 hours to obtain a nanofiber highly moisture permeable waterproof fabric with multi-level interconnected pores.

[0012] Preferably, the substrate is pure polyester woven or non-woven fabric with a gram weight of 40 to 300 g / m 2 .

[0013] Preferably, the hydrophilic polyurethane nanofiber membrane is formed by electrostatic spinning of a polyurethane spinning solution, and the hydrophilic polyurethane is a polyether polyurethane.

[0014] Preferably, the hydrophobic polyvinyl alcohol nanofiber membrane is formed by electrospinning a polyvinyl alcohol spinning solution, and the polyvinyl alcohol spinning solution consists of polyvinyl alcohol, isocyanate crosslinker, and deionized water. The concentration of polyvinyl alcohol is 3 to 10% by weight, the concentration of isocyanate crosslinker is 2 to 8% by weight, and the balance is deionized water.

[0015] Preferably, the number average molecular weight of the polyvinyl alcohol is 50,000 to 130,000, and the alcoholysis degree is one of 88% and 99%; and the isocyanate crosslinking agent is an aliphatic isocyanate crosslinking agent.

[0016] Preferably, the hot melt adhesive coating method is one of spiral spraying, fiber spraying, and rolling glue, and the amount of glue applied is 1 to 20 g / m 2 .

[0017] Preferably, the adhesive is a moisture-curing reactive polyurethane hot melt adhesive.

[0018] Beneficial effects

[0019] The present invention provides a nanofiber high moisture permeability waterproof fabric with multi-level interconnected channels. The fabric body includes an outer layer, a middle layer and an inner layer. The outer layer is a pure polyester waterproof fabric that has been waterproofed, the middle layer is a nanofiber membrane with multi-level interconnected channels, and the inner layer is a pure polyester fabric. The nanofiber membrane with multi-level interconnected channels in the middle layer is formed by stacking multiple nanofiber membrane layers in sequence. Each nanofiber membrane layer has two nanofiber membranes with different fiber diameters, one layer is a hydrophilic polyurethane nanofiber membrane, and the other layer is a hydrophobic polyvinyl alcohol nanofiber membrane. The nanofibers of the two membranes in the membrane layer are cross-connected to form a three-dimensional structure with multi-level interconnected channels, and the pore size gradually decreases from the hydrophilic polyurethane nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane; the "hydrophilic-hydrophobic-hydrophilic-hydrophobic" structure formed by the multi-level nanofiber membrane layer quickly transfers water vapor to the outside through the "adsorption-diffusion-desorption-adsorption-diffusion-desorption" method; at the same time, the pore size gradually decreases from the hydrophilic polyurethane nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane, thereby forming a capillary effect, which is conducive to the volatilization of water vapor and improves the moisture permeability of the fabric, and the moisture permeability is higher than 15000g / (m 2 24 hours); hydrophobic polyvinyl alcohol nanofibers are cross-linked with isocyanate to form hydrophobic, small-pore nanofibers, which adhere to the outer waterproof fabric to improve the fabric's waterproof effect. The hydrostatic pressure of the fabric can exceed 60kPa, meeting the index requirements of waterproof fabrics such as jackets. DETAILED DESCRIPTION

[0020] To further understand the present invention, the following examples are described. However, it should be understood that these examples are intended only to further illustrate the features and advantages of the present invention and are not intended to limit the scope of the present invention. The polyurethane used in the examples was purchased from Zhejiang Huafeng New Materials Co., Ltd., model JF-TA-FS6120.

[0021] Example 1

[0022] Nanofiber high breathability waterproof fabric with multi-level interconnected channels, the main body of the fabric consists of outer layer, middle layer and inner layer. The outer layer is pure polyester waterproof fabric with waterproof finishing, warp fineness 150D, weft fineness 150D, yarn density 800T, gram weight 250g / m 2, hydrostatic pressure 10kPa; the inner side is bonded to the hydrophobic polyvinyl alcohol nanofiber membrane of the middle layer with multi-level interconnected channels through hot melt adhesive. The middle layer is a nanofiber membrane with multi-level interconnected channels, which consists of three levels of nanofiber membrane layers, from the inside to the outside: hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber-hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber-hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber, the average diameter of the hydrophilic polyurethane nanofiber is 200nm, the average pore size is 2.5um, and the gram weight is 10g / m 2 The average diameter of the hydrophobic polyvinyl alcohol nanofibers is 90nm, the average pore size is 0.8um, and the gram weight is 10g / m 2 The inner layer is made of pure polyester fabric, with a yarn fineness of 100D and a weight of 60g / m 2 The inner layer fabric is bonded to the middle layer of a hydrophilic polyurethane nanofiber membrane having a nanofiber membrane with multi-level interconnected pores.

[0023] The preparation method of the nanofiber high moisture permeability and waterproof fabric with multi-level interconnected pores comprises the following specific steps:

[0024] Step 1: Prepare a silicone waterproofing agent finishing liquid with a concentration of 8% by weight, and use a dipping and padding method to finish the outer layer of pure polyester fabric. After the dipping and padding are completed, dry it at a drying temperature of 130° C. and a drying time of 10 minutes to obtain the outer layer waterproof fabric.

[0025] Step 2: prepare polyvinyl alcohol spinning solution, wherein the number average molecular weight of polyvinyl alcohol is 70,000, the alcoholysis degree is 88%, the weight percentage of polyvinyl alcohol is 5%, the weight percentage of aliphatic isocyanate emulsion is 4%, and the balance is deionized water.

[0026] Step 3: Use polyester fabric as the receiving substrate of the nanofiber membrane for electrospinning. The weight of the polyester fabric is 50g / m 2 First, hydrophilic polyurethane nanofibers were loaded on the polyester fabric substrate, the polyurethane spinning solution was added to the barrel of the spinning unit, and the spinning process was set to a spinning voltage of 70 kV and a receiving distance of 230 mm; then, hydrophobic polyvinyl alcohol nanofibers were loaded, the polyethanol spinning solution was added to the barrel of the spinning unit, the spinning voltage was set to 80 kV, and the receiving distance was set to 230 mm; the above nanofiber loading sequence and spinning process were repeated three times to obtain a nanofiber membrane with multi-level interconnected channels; after spinning was completed, cross-linking treatment was performed at 130°C for 20 minutes.

[0027] Step 4: Heat the hot melt adhesive to 170℃ and melt it. Use spiral spraying to apply the adhesive material to the outer waterproof fabric. Compound the outer waterproof fabric with the base fabric loaded with nanofiber membrane. The amount of adhesive applied is 20g / m 2After the composite is completed, the base fabric is quickly peeled off and the nanofiber membrane is transferred to the outer waterproof fabric.

[0028] Step 5: Use spiral spraying to apply glue material to the inner fabric, and then laminate the inner fabric with the outer waterproof fabric with nanofiber. The amount of glue applied is 2g / m 2 .

[0029] Step 6: After the compounding is completed, the composite is cured at room temperature for 48 hours to obtain a nanofiber highly breathable and waterproof fabric with multi-level interconnected pores.

[0030] Example 2

[0031] Nanofiber high breathability waterproof fabric with multi-level interconnected channels, the main body of the fabric consists of outer layer, middle layer and inner layer. The outer layer is pure polyester waterproof fabric with waterproof finishing, warp fineness 20D, weft fineness 20D, yarn density 500T, gram weight 105g / m 2 , hydrostatic pressure 2kPa; the inner side is bonded to the hydrophobic polyvinyl alcohol nanofiber membrane of the middle layer with multi-level interconnected channels through hot melt adhesive. The middle layer is a nanofiber membrane with multi-level interconnected channels, which consists of three levels of nanofiber membrane layers, from the inside to the outside: hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber-hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber-hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber. The average diameter of the hydrophilic polyurethane nanofiber is 380nm, the average pore size is 4um, and the gram weight is 18g / m 2 The average diameter of the hydrophobic polyvinyl alcohol nanofibers is 120nm, the average pore size is 0.2um, and the gram weight is 15g / m 2 The inner layer is made of pure polyester fabric, with a yarn fineness of 10D and a weight of 30g / m 2 The inner layer fabric is bonded to the middle layer of a hydrophilic polyurethane nanofiber membrane having a nanofiber membrane with multi-level interconnected pores.

[0032] The preparation method of the above-mentioned nanofiber high moisture permeability and waterproof fabric with multi-level interconnected pores comprises the following specific steps:

[0033] Step 1: Prepare a silicone waterproofing agent finishing liquid with a concentration of 2% by weight, and use a dipping and padding method to finish the outer layer of pure polyester fabric. After the dipping and padding are completed, dry it at a drying temperature of 130° C. and a drying time of 10 minutes to obtain the outer layer waterproof fabric.

[0034] Step 2: prepare polyvinyl alcohol spinning solution, wherein the number average molecular weight of polyvinyl alcohol is 70,000, the alcoholysis degree is 88%, the weight percentage of polyvinyl alcohol is 9%, the weight percentage of aliphatic isocyanate emulsion is 8%, and the balance is deionized water.

[0035] Step 3: Use polyester fabric as the receiving substrate of the nanofiber membrane for electrospinning. The weight of the polyester fabric is 100g / m 2 First, hydrophilic polyurethane nanofibers were loaded on the polyester fabric substrate, the polyurethane spinning solution was added to the barrel of the spinning unit, and the spinning process was set to a spinning voltage of 70 kV and a receiving distance of 230 mm; then, hydrophobic polyvinyl alcohol nanofibers were loaded, the polyethanol spinning solution was added to the barrel of the spinning unit, the spinning voltage was set to 60 kV, and the receiving distance was set to 230 mm; the above nanofiber loading sequence and spinning process were repeated three times to obtain a nanofiber membrane with multi-level interconnected channels; after spinning was completed, cross-linking treatment was performed at 150°C for 10 minutes.

[0036] Step 4: Heat the hot melt adhesive to 170℃ and melt it. Apply the adhesive material to the outer waterproof fabric by rolling glue. Composite the outer waterproof fabric with the base fabric loaded with nanofiber membrane. The amount of adhesive applied is 10g / m 2 After the composite is completed, the base fabric is quickly peeled off and the nanofiber membrane is transferred to the outer waterproof fabric.

[0037] Step 5: Use the rolling glue method to apply the glue material to the inner layer of fabric, and compound the inner layer of fabric with the outer layer of waterproof fabric with nanofiber. The amount of glue applied is 2g / m 2 .

[0038] Step 6: After the compounding is completed, the composite is cured at room temperature for 48 hours to obtain a nanofiber highly breathable and waterproof fabric with multi-level interconnected pores.

[0039] Example 3

[0040] Nanofiber high breathability waterproof fabric with multi-level interconnected channels, the main body of the fabric consists of outer layer, middle layer and inner layer. The outer layer is pure polyester waterproof fabric with waterproof finishing, warp fineness 100D, weft fineness 150D, yarn density 600T, gram weight 200g / m 2 , hydrostatic pressure 6kPa; the inner side is bonded to the hydrophobic polyvinyl alcohol nanofiber membrane of the middle layer with multi-level interconnected channels through hot melt adhesive. The middle layer is a nanofiber membrane with multi-level interconnected channels, which consists of three levels of nanofiber membrane layers, from the inside to the outside: hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber-hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber-hydrophilic polyurethane nanofiber-hydrophobic polyvinyl alcohol nanofiber, the average diameter of the hydrophilic polyurethane nanofiber is 150nm, the average pore size is 3.1um, and the gram weight is 2g / m 2 The average diameter of the hydrophobic polyvinyl alcohol nanofibers is 50nm, the average pore size is 1.8um, and the gram weight is 4g / m 2 The inner fabric is pure polyester fabric, yarn fineness 50D, weight 50g / m 2The inner layer fabric is bonded to the middle layer of a hydrophilic polyurethane nanofiber membrane having a nanofiber membrane with multi-level interconnected pores.

[0041] The preparation method of the nanofiber high moisture permeability and waterproof fabric with multi-level interconnected pores comprises the following specific steps:

[0042] Step 1: Prepare a silicone waterproofing agent finishing liquid with a concentration of 5% by weight, and use a dipping and padding method to finish the outer layer of pure polyester fabric. After the dipping and padding are completed, dry it at a drying temperature of 130° C. and a drying time of 10 minutes to obtain the outer layer waterproof fabric.

[0043] Step 2: prepare polyvinyl alcohol spinning solution, wherein the number average molecular weight of polyvinyl alcohol is 70,000, the alcoholysis degree is 88%, the weight percentage of polyvinyl alcohol is 3%, the weight percentage of aliphatic isocyanate emulsion is 2%, and the balance is deionized water.

[0044] Step 3: Use polyester fabric as the receiving substrate of the nanofiber membrane for electrospinning. The weight of the polyester fabric is 200g / m 2 First, hydrophilic polyurethane nanofibers were loaded on the polyester fabric substrate, the polyurethane spinning solution was added to the barrel of the spinning unit, and the spinning process was set to a spinning voltage of 70 kV and a receiving distance of 230 mm; then, hydrophobic polyvinyl alcohol nanofibers were loaded, the polyethanol spinning solution was added to the barrel of the spinning unit, the spinning voltage was set to 80 kV, and the receiving distance was set to 230 mm; the above nanofiber loading sequence and spinning process were repeated three times to obtain a nanofiber membrane with multi-level interconnected channels; after spinning was completed, cross-linking treatment was performed at 180°C for 2 minutes.

[0045] Step 4: Heat the hot melt adhesive to 170℃ and melt it. Apply the adhesive material to the outer waterproof fabric by rolling glue. Composite the outer waterproof fabric with the base fabric loaded with nanofiber membrane. The amount of adhesive applied is 15g / m 2 After the composite is completed, the base fabric is quickly peeled off and the nanofiber membrane is transferred to the outer waterproof fabric.

[0046] Step 5: Use the glue rolling method to apply the glue material to the inner layer of fabric, and then laminate the inner layer of fabric with the outer layer of waterproof fabric with nanofiber. The amount of glue applied is 3g / m 2 .

[0047] Step 6: After the compounding is completed, the composite is cured at room temperature for 48 hours to obtain a nanofiber highly breathable and waterproof fabric with multi-level interconnected pores.

[0048] The nanofiber, highly breathable and waterproof fabrics with multi-level interconnected pores produced in Examples 1, 2, and 3 were tested for hydrostatic pressure and moisture permeability before and after washing. The washing method followed the 4N cycle of a type A washing machine in GB / T 8629-2017, using "Standard Detergent 3" as the detergent. The drying cycle was A-line drying, with three washes, followed by line drying after each wash. The hydrostatic pressure test followed GB / T 4744-2013, "Test and Evaluation of Waterproof Properties of Textiles - Hydrostatic Pressure Method," and the moisture permeability test followed Method B (inverted cup method) in GB / T 12704.2-2009, "Test Method for Water Vapor Permeability of Textile Fabrics - Part 2: Evaporation Method." The test results are shown in Table 1. The hydrostatic pressure and moisture permeability of the examples far exceeded the standard requirements for Class I fabrics in GB / T 32614-32614, "Fabrics for Outdoor Sportswear."

[0049] Table 1 Hydrostatic pressure and moisture permeability of the nanofiber high moisture permeability waterproof fabric prepared in Example before and after washing

[0050] Hydrostatic pressure (kPa) <![CDATA[Water vapor transmission rate [g / (m 2 ·24h)]]]> Example 1 (before washing) 72 15600 Example 1 (after washing) 67 16700 Example 2 (before washing) 78 15200 Example 2 (after washing) 72 15800 Example 3 (before washing) 80 16000 Example 3 (after washing) 75 16500

[0051] The implementation methods of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A nanofiber high moisture permeability and waterproof fabric with multi-level interconnected pores, comprising an outer layer, an intermediate layer and an inner layer, characterized in that: The outer layer is made of pure polyester waterproof fabric with waterproof finishing. The yarn fineness of the fabric is 20-150D, density is 500-1000T, and weight is 100-250g / m 2 , hydrostatic pressure 2~10kPa; the middle layer is a nanofiber membrane with multi-level interconnected channels, which is composed of multi-level nanofiber membrane layers stacked in sequence. Each nanofiber membrane layer has two layers of nanofiber membranes with different fiber diameters, one layer is a hydrophilic polyurethane nanofiber membrane with a pore size range of 2~4um, and the other layer is a hydrophobic polyvinyl alcohol nanofiber membrane with a pore size range of 0.1~2um. The nanofibers of the two membranes in the membrane layer are cross-connected to form a three-dimensional structure with multi-level interconnected channels, and the pore size gradually decreases from the hydrophilic polyurethane nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane; the inner layer is pure polyester fabric with a yarn fineness of 10~100D and a gram weight of 30~60g / m 2 The inner side of the outer pure polyester waterproof fabric is bonded to the hydrophobic polyvinyl alcohol nanofiber membrane of the middle layer with multi-level interconnected pores through hot melt adhesive compounding, and the inner pure polyester fabric is bonded to the hydrophilic polyurethane nanofiber membrane of the middle layer with multi-level interconnected pores through hot melt adhesive compounding.

2. The nanofiber high moisture permeability and waterproof fabric with multi-level interconnected channels according to claim 1, characterized in that: The hydrophilic polyurethane nanofiber membrane has a gram weight of 0.5 to 20 g / m 2 , the fiber diameter ranges from 140 to 400 nm.

3. The nanofiber high moisture permeability and waterproof fabric with multi-level interconnected channels according to claim 1, characterized in that: The hydrophobic polyvinyl alcohol nanofiber membrane has a gram weight of 0.5 to 20 g / m 2 , the fiber diameter ranges from 50 to 130 nm.

4. The method for preparing the nanofiber highly moisture-permeable and waterproof fabric with multi-level interconnected pores according to claim 1, characterized in that: The following steps are involved: (1) preparing a silicone waterproofing agent finishing liquid with a concentration of 2-8% by weight, and performing waterproof finishing on the pure polyester fabric as the outer layer by a padding method, wherein the padding process is one dip and one padding, and drying at 100-150° C. for 10-20 minutes after the padding is completed to obtain the outer layer waterproof fabric; (2) The nanofiber membranes are alternately stacked on the substrate by electrospinning, firstly loading a layer of hydrophilic polyurethane nanofiber membrane, and then loading a layer of hydrophobic polyvinyl alcohol nanofiber membrane, and the cycle is repeated multiple times to form a nanofiber membrane with multi-level interconnected pores; after the spinning is completed, the nanofiber membrane is cross-linked at 130-180°C for 2-20 minutes; (3) The substrate of the nanofiber membrane with multi-level interconnected pores obtained in step (2) is compounded with the outer waterproof fabric obtained in step (1) by a hot melt adhesive compounding method, so that the inner side of the outer waterproof fabric is adhered to the hydrophobic polyvinyl alcohol nanofiber membrane of the nanofiber membrane with multi-level interconnected pores. After the compounding is completed, the substrate is peeled off and the nanofiber membrane with multi-level interconnected pores is transferred to the outer waterproof fabric; (4) The outer layer waterproof fabric of the nanofiber membrane with multi-level interconnected pores is compounded with the inner layer fabric by hot melt adhesive compounding. After the compounding is completed, it is cured for 40 to 50 hours to obtain a nanofiber highly moisture permeable waterproof fabric with multi-level interconnected pores.

5. The method for preparing the nanofiber high moisture permeability and waterproof fabric with multi-level interconnected pores according to claim 4, characterized in that: The substrate is pure polyester woven fabric or non-woven fabric with a gram weight of 40 to 300 g / m 2 .

6. The method for preparing the nanofiber highly moisture-permeable and waterproof fabric with multi-level interconnected pores according to claim 4, characterized in that: The hydrophilic polyurethane nanofiber membrane is formed by electrostatic spinning of a polyurethane spinning solution, and the hydrophilic polyurethane is a polyether polyurethane.

7. The method for preparing the nanofiber highly moisture-permeable and waterproof fabric with multi-level interconnected pores according to claim 4, characterized in that: The hydrophobic polyvinyl alcohol nanofiber membrane is formed by electrostatic spinning of polyvinyl alcohol spinning solution, which consists of polyvinyl alcohol, isocyanate crosslinking agent and deionized water. The concentration of polyvinyl alcohol is 3-10% by weight, the concentration of isocyanate crosslinking agent is 2-8% by weight, and the balance is deionized water.

8. The method for preparing the nanofiber highly moisture-permeable and waterproof fabric with multi-level interconnected pores according to claim 7, characterized in that: The number average molecular weight of the polyvinyl alcohol is 50,000-130,000, and the alcoholysis degree is one of 88% and 99%. The isocyanate crosslinking agent is an aliphatic isocyanate crosslinking agent.

9. The method for preparing a nanofiber highly moisture-permeable and waterproof fabric with multi-level interconnected pores according to claim 4, characterized in that: The hot melt adhesive composite coating method is one of spiral spraying, fiber spraying, and rolling glue, and the amount of glue applied is 1 to 20 g / m 2 .

10. The method for preparing the nanofiber highly moisture-permeable and waterproof fabric with multi-level interconnected pores according to claim 4, characterized in that: The hot melt adhesive is a moisture curing reactive polyurethane hot melt adhesive.