Nanofiber high-moisture-permeability waterproof fabric with multistage communicated pore channels and preparation method of nanofiber high-moisture-permeability waterproof fabric

Abstract

The invention belongs to the field of nanofiber composite fabric preparation, and provides a nanofiber high-moisture-permeability waterproof fabric with multi-stage communicated pore canals and a preparation method thereof.The fabric body comprises an outer layer, a middle layer and an inner layer, the outer layer is a pure polyester waterproof fabric subjected to waterproof finishing, the middle layer is a nanofiber membrane with the multi-stage communicated pore canals, and the inner layer is a nano-fiber membrane with the multi-stage communicated pore canals; the inner layer is a pure polyester fabric; the inner side of the outer-layer pure polyester waterproof fabric is attached to the hydrophobic polyvinyl alcohol nanofiber membrane of the nanofiber membrane with the multi-stage communicated pore channels in the middle layer through hot melt adhesive compounding, and the inner-layer pure polyester fabric is attached to the hydrophilic polyurethane nanofiber membrane of the nanofiber membrane with the multi-stage communicated pore channels in the middle layer through hot melt adhesive compounding. The middle layer of the nanofiber membrane is formed by sequentially overlapping multiple stages of nanofiber membrane layers, each stage of nanofiber membrane layer is provided with 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; nanofibers of two membranes among the multistage nanofiber membrane layers and in the membrane layers are in cross lap joint to form a three-dimensional structure with multistage communicated pore channels, and the pore diameter is gradually reduced from the hydrophilic polyurethane nanofiber membrane to the hydrophobic polyvinyl alcohol nanofiber membrane. The moisture permeability is higher than 15000g / (m < 2 >. 24h), and the hydrostatic pressure is higher than 60kPa.

Description

Technical Field

[0001] The invention relates to a nanofiber high moisture permeability 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. As the main fabric of the jacket fabric, polyurethane coated fabric has a good waterproof effect, but the moisture permeability is very poor and the comfort is low; PTFE membrane material as the inner layer structure of the nanofiber jacket fabric has improved moisture permeability, but fluorine-containing materials have certain harm 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 for electrospinning, and obtain an electrospun nanofiber membrane on a receiving device, and 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 hot-roll it to make a high-efficiency waterproof and breathable fabric. The hydrophobic nanoparticles in the patent are polytetrafluoroethylene. The raw material perfluorooctanoic acid used in the production process is carcinogenic. Polytetrafluoroethylene is difficult to degrade in the environment, which poses a hidden danger to the environment. 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 waterproof fabric with multi-level interconnected channels, wherein the middle layer is a nanofiber membrane with multi-level interconnected channels, 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 um, and the other layer is a hydrophobic polyvinyl alcohol nanofiber membrane with a pore size range of 0.1 to 2 um. The nanofibers of the two membranes in the membrane layer are cross-lapped to form a three-dimensional structure with multi-level interconnected channels, and the pore size is determined by the hydrophilic polyurethane. The pore size gradually decreases from the hydrophilic polyurethane 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 improves 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 after 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 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 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-lapped 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, the yarn fineness of the fabric is 10~100D, and the gram weight is 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 of nanofiber membrane with multi-level interconnected channels by hot melt adhesive compound, and the inner pure polyester fabric is bonded to the hydrophilic polyurethane nanofiber membrane of the middle layer of nanofiber membrane with multi-level interconnected channels by hot melt adhesive compound.

[0005] Preferably, the hydrophilic polyurethane nanofiber membrane has a 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 channels, the steps of which are:

[0008] (1) preparing a siloxane 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, thereby obtaining the outer layer waterproof fabric;

[0009] (2) The nanofiber membranes are alternately stacked on the substrate by electrospinning in sequence, firstly a layer of hydrophilic polyurethane nanofiber membrane is loaded, and then a layer of hydrophobic polyvinyl alcohol nanofiber membrane is loaded, 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 min;

[0010] (3) Compounding the substrate of the nanofiber membrane with multi-level interconnected channels obtained in step (2) with the outer waterproof fabric obtained in step (1) by hot melt adhesive compounding, 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 channels are bonded together, and after the compounding is completed, peeling off the substrate, and transferring the nanofiber membrane with multi-level interconnected channels to the outer waterproof fabric;

[0011] (4) The outer layer waterproof fabric of the nanofiber membrane with multi-level interconnected channels is compounded with the inner layer fabric by a hot melt adhesive compounding method. 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 channels.

[0012] Preferably, the substrate is pure polyester woven fabric 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 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.

[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 composite coating method is one of spiral spraying, fiber spraying, and rolling glue, and the amount of glue applied is 1-20g / 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, wherein the fabric body comprises an outer layer, a middle layer and an inner layer, wherein 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 pores 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-lapped to form a three-dimensional structure with multi-level interconnected pores, 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" mode; 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 ·24h); hydrophobic polyvinyl alcohol nanofibers are cross-linked by isocyanate to form hydrophobic, small-pore nanofibers, which are bonded to the outer waterproof fabric to improve the waterproof effect of the fabric. The hydrostatic pressure of the fabric can be higher than 60kPa, meeting the index requirements of waterproof fabrics such as assault jackets. DETAILED DESCRIPTION

[0020] In order to further understand the present invention, the present invention is described below in conjunction with the embodiments, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention. The polyurethane in the embodiments was purchased from Zhejiang Huafeng New Materials Co., Ltd., model JF-TA-FS6120.

[0021] Example 1

[0022] Nanofiber high moisture permeability waterproof fabric with multi-level interconnected channels, the main body of the fabric includes an outer layer, a middle layer and an inner layer. The outer layer is a pure polyester waterproof fabric with waterproof finishing, warp yarn fineness 150D, weft yarn 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 3 levels of nanofiber membrane layers, from inside to 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, with a yarn fineness of 100D and a weight of 60g / m 2 The inner layer fabric is laminated with the middle layer of 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 an outer layer waterproof fabric.

[0025] Step 2: prepare polyvinyl alcohol spinning solution, the number average molecular weight of polyvinyl alcohol is 70000, 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 into the barrel of the spinning unit, 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 into 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 3 times to obtain a nanofiber membrane with multi-level interconnected channels; after spinning, cross-linking treatment was performed at 130°C for 20 min.

[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 lamination 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 glue spraying to apply glue material to the inner layer of fabric, and laminate the inner layer of fabric with the outer waterproof fabric with nanofibers. The amount of glue applied is 2g / m 2 .

[0029] Step 6: After the compounding is completed, the mixture 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 moisture permeability waterproof fabric with multi-level interconnected channels, the main body of the fabric includes an outer layer, a middle layer and an inner layer. The outer layer is a pure polyester waterproof fabric with waterproof finishing, warp yarn fineness 20D, weft yarn fineness 20D, yarn density 500T, gram weight 105g / m 2 , hydrostatic pressure 2kPa; the inner side is bonded with the hydrophobic polyvinyl alcohol nanofiber membrane of the middle layer of nanofiber membrane with multi-level interconnected channels by hot melt adhesive. The middle layer is a nanofiber membrane with multi-level interconnected channels, which consists of 3 levels of nanofiber membrane layers, from inside to 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, with a yarn fineness of 10D and a weight of 30g / m 2 The inner layer fabric is laminated with the middle layer of hydrophilic polyurethane nanofiber membrane having a nanofiber membrane with multi-level interconnected pores.

[0032] The preparation method of the 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 an outer layer waterproof fabric.

[0034] Step 2: prepare polyvinyl alcohol spinning solution, the number average molecular weight of polyvinyl alcohol is 70000, 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 into the barrel of the spinning unit, 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 into 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 3 times to obtain a nanofiber membrane with multi-level interconnected channels; after spinning, the membrane was cross-linked at 150°C for 10 min.

[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. Compound the outer waterproof fabric with the base fabric loaded with nanofiber membrane. The amount of adhesive applied is 10g / m 2 After the lamination 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 the fabric, and laminate the inner layer of the fabric with the outer layer of the waterproof fabric with nanofibers. The amount of glue applied is 2g / m 2 .

[0038] Step 6: After the compounding is completed, the mixture 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 moisture permeability waterproof fabric with multi-level interconnected channels, the main body of the fabric includes outer layer, middle layer and inner layer. The outer layer is pure polyester waterproof fabric with waterproof finishing, warp yarn fineness 100D, weft yarn 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 layer is made of pure polyester, with a yarn fineness of 50D and a weight of 50g / m 2The inner layer fabric is laminated with the middle layer of 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 dipping and padding, dry it at a temperature of 130° C. and a drying time of 10 minutes to obtain an outer layer waterproof fabric.

[0043] Step 2: prepare polyvinyl alcohol spinning solution, the number average molecular weight of polyvinyl alcohol is 70000, 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 are loaded on the polyester fabric substrate, the polyurethane spinning solution is added into the barrel of the spinning unit, the spinning process is set to a spinning voltage of 70 kV, and a receiving distance of 230 mm; then, hydrophobic polyvinyl alcohol nanofibers are loaded, the polyethanol spinning solution is added into the barrel of the spinning unit, the spinning voltage is set to 80 kV, and the receiving distance is set to 230 mm; the above nanofiber loading sequence and spinning process are repeated three times to obtain a nanofiber membrane with multi-level interconnected channels; after spinning, cross-linking treatment is performed at 180°C for 2 min.

[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. Compound the outer waterproof fabric with the base fabric loaded with nanofiber membrane. The amount of adhesive applied is 15g / m 2 After the lamination 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 laminate the inner layer of fabric with the outer layer of waterproof fabric with nanofibers. The amount of glue applied is 3g / m 2 .

[0047] Step 6: After the compounding is completed, the mixture 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 high moisture permeability waterproof fabric with multi-level interconnected pores prepared in Examples 1, 2, and 3 was tested to test the hydrostatic pressure and moisture permeability before and after washing. The washing method was carried out in accordance with the provisions of the 4N program of the A-type washing machine in GB / T 8629-2017, the detergent was "standard detergent 3", the drying program was A-hanging and drying, the number of washings was 3 times, and hanging and drying was performed after each washing. The test method for hydrostatic pressure was tested in accordance with GB / T 4744-2013 "Hydrostatic pressure method for testing and evaluating the waterproof performance of textiles", and the test method for moisture permeability was tested in accordance with method B (inverted cup method) in GB / T12704.2-2009 "Test method for moisture permeability of textile fabrics Part 2: Evaporation method". The test results are shown in Table 1. The hydrostatic pressure and moisture permeability of the embodiment are much higher than the standard requirements for Class I fabrics in GB / T 32614-32614 "Outdoor sportswear jacket fabrics".

[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, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A nanofiber highly breathable 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, the density is 500-1000T, and the 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 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 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-lapped 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, the yarn fineness of the fabric is 10~100D, and the gram weight is 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 of nanofiber membrane with multi-level interconnected channels by hot melt adhesive compound, and the inner pure polyester fabric is bonded to the hydrophilic polyurethane nanofiber membrane of the middle layer of nanofiber membrane with multi-level interconnected channels by hot melt adhesive compound.

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 highly moisture-permeable nanofiber waterproof fabric according to claim 1, characterized in that: The following steps are involved: (1) preparing a siloxane 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, thereby obtaining the outer layer waterproof fabric; (2) The nanofiber membranes are alternately stacked on the substrate by electrospinning in sequence, firstly a layer of hydrophilic polyurethane nanofiber membrane is loaded, and then a layer of hydrophobic polyvinyl alcohol nanofiber membrane is loaded, 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 min; (3) Compounding the substrate of the nanofiber membrane with multi-level interconnected pores obtained in step (2) with the outer waterproof fabric obtained in step (1) by hot melt adhesive compounding, 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 bonded together, and after the compounding is completed, peeling off the substrate, and transferring the nanofiber membrane with multi-level interconnected pores 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 method. After the compounding is completed, it is cured for 40 to 50 hours to obtain the nanofiber highly moisture permeable waterproof fabric with multi-level interconnected pores.

5. 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 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 polyurethane spinning solution, and the hydrophilic polyurethane is 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 a polyvinyl alcohol spinning solution, which consists of polyvinyl alcohol, an isocyanate crosslinking agent, and deionized water. The concentration of the polyvinyl alcohol is 3 to 10% by weight, the concentration of the isocyanate crosslinking agent is 2 to 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 the 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 1-20g / 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.