Fluoride-free waterproof sound-transmitting film and preparation method thereof

Abstract

The invention discloses a fluoride-free waterproof sound-transmitting film and a preparation method thereof, and the fluoride-free waterproof sound-transmitting film comprises the following components in percentage by mass: 30-40% of a fluoride-free polymer; 4.5%-11.5% of a fluoride-free waterproof agent; 0.5%-3.5% of a cross-linking agent and 45%-65% of a solvent; the solvent is a mixed solvent of N 'N-dimethylformamide, N' N-dimethylacetamide, acetone and ethyl acetate, and the mass ratio of the amide solvent in the mixed solvent is 60%-85%; the preparation method of the fluoride-free waterproof sound-transmitting film comprises the following steps: preparing a spinning solution; carrying out electrostatic spinning by utilizing electrostatic spinning equipment to obtain a continuous and uniform nano spinning membrane; the method comprises the following steps: uniformly depositing nanofibers on a nano spinning film base material, and carrying out post-treatment to obtain a finished product of the fluoride-free waterproof sound-transmitting film, the fluorine-free safe and healthy product with good water resistance and air permeability, high rebound resilience and excellent acoustic performance is successfully prepared through selection of raw materials, preparation of a spinning solution, spinning process parameters and fine regulation and control of post-treatment conditions.

Description

Technical Field

[0001] The invention relates to the technical field of functional film materials, and in particular to a fluorine-free waterproof sound-permeable membrane and a preparation method thereof. Background Art

[0002] Waterproof and sound-permeable membrane is a material that has both waterproof and sound-permeable functions. It is widely used in electronic equipment, medical equipment, industrial equipment and other fields. With the miniaturization and multifunctionalization of electronic equipment, the demand for waterproof and sound-permeable membranes is increasing. Traditional waterproof and sound-permeable membranes mostly use expanded polytetrafluoroethylene (ePTFE) or some other fluorine-containing materials. Although such materials can provide a certain waterproof or hydrophobic effect, these materials themselves are fluorine-containing materials. Some of them will release harmful substances such as PFAS during the production process, which poses potential risks to the environment and human health. Such substances have been restricted by multiple laws in many countries. In addition, traditional materials may not be able to meet the requirements of waterproofness, breathability, high audio consistency and low sound loss at the same time. With the enhancement of environmental awareness and the development of technology, the development of waterproof and sound-permeable membranes that do not contain fluorine and have good acoustic properties has become a research hotspot.

[0003] Therefore, the present invention provides a fluorine-free waterproof sound-permeable membrane and a preparation method thereof. The fluorine-free waterproof sound-permeable membrane prepared by the present invention has excellent resilience based on the waterproof and breathable properties of traditional waterproof sound-permeable membranes. After a hydrostatic pressure test, it can rebound quickly and restore its good acoustic properties. Summary of the invention

[0004] The purpose of the present invention is to provide a fluorine-free waterproof and sound-permeable membrane and a preparation method thereof, so as to obtain a safe and healthy product with excellent waterproof and breathable properties, outstanding acoustic properties and no fluorine.

[0005] The purpose of the present invention is achieved through the following technical solutions: A fluorine-free waterproof sound-permeable membrane, comprising, by mass percentage: 30% to 40% of a fluorine-free polymer; 4.5% to 11.5% of a fluorine-free waterproof agent; 0.5% to 3.5% of a cross-linking agent; and 45% to 65% of a solvent; Wherein, the fluorine-free waterproofing agent is an oily fluorine-free waterproofing agent, and the oily fluorine-free waterproofing agent includes but is not limited to polyurethane oily fluorine-free waterproofing agent and long-chain alkane oily fluorine-free waterproofing agent; The fluorine-free polymers include, but are not limited to, polyurethane, polyacrylonitrile and polystyrene; The cross-linking agent is selected from one or more of an isocyanate cross-linking agent, an amino cross-linking agent, and an organosilicon cross-linking agent; The solvent is N'N-dimethylformamide, N'N-dimethylacetamide, and a mixed solvent of acetone and ethyl acetate, and the mass proportion of the amide solvent in the mixed solvent is 60% to 85%.

[0006] Furthermore, the oily fluorine-free waterproofing agent is a natural or synthetic fluorine-free compound.

[0007] Preferably, the organosilicon crosslinking agent is aminopropyltriethoxysilane (APTES) or γ-glycidyloxypropyltrimethoxysilane (GPTMS) or γ-methacryloxypropyltrimethoxysilane (MAPTMS) or methyltrimethoxysilane (MTMS) or tetraethoxysilane (TEOS) or hexamethyldisilazane (HMDS) or tetramethyldisilazane (TMDS).

[0008] Preferably, the isocyanate crosslinking agent is toluene diisocyanate (TDI) or hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI) or tetramethylxylylene diisocyanate (TMXDI) or cyclohexane diisocyanate (CHDI).

[0009] Preferably, the amino crosslinking agent is ethylenediamine (EDA) or diethylenetriamine (DETA) or triethylenetetramine (TETA) or aminopropyltriethoxysilane (APTES) or N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (AEPTMS).

[0010] Preferably, the polyurethane oily fluorine-free waterproofing agent is selected from one or more of polyurethane prepolymer, polyurethane modified oil, polyurethane acrylate, polyurethane modified epoxy resin, and polyurethane silicone oil.

[0011] Preferably, the long-chain alkane oily fluorine-free waterproofing agent is selected from one or more of microcrystalline wax, polyethylene wax, oxidized polyethylene wax, Fischer-Tropsch wax, and alkyl ketene dimer (AKD).

[0012] A method for preparing a fluorine-free waterproof sound-permeable membrane comprises the following steps: S1. Preparation of spinning solution: Put the solvent into a stirring device, disperse the fluorine-free polymer and the fluorine-free waterproofing agent in the solvent, add the cross-linking agent thereto and stir to form a spinning solution, stir for 12 to 20 hours to make the spinning solution form a homogeneous system, and let it stand for 3 to 6 hours after stirring to discharge the bubbles in the spinning solution; S2, electrospinning: adding the spinning solution from which the bubbles are discharged in step S1 into the electrospinning device, adjusting the liquid output of the nozzle by controlling the liquid supply speed of each module of the electrospinning device, and controlling the weight of the deposited nanospinning membrane by matching the running speed of the conveyor belt used for collection, and controlling the diameter and morphology of the nanofibers by controlling the size of the high-voltage electric field of the high-voltage system and the receiving distance between the spinning needle and the collecting area; obtaining a continuous and uniform nanospinning membrane by controlling the swing amplitude and swing speed of the array needle system of each module; S3, winding: the rolled nanospinning membrane substrate is used as a collecting auxiliary material and runs along the conveyor belt. After passing through the array needle system of each module, the nanofibers are evenly deposited on the nanospinning membrane substrate and enter the winding device; S4, post-processing: sending the received nanofiber nanospinning membrane to a post-processing device, adjusting the temperature, pressing time and pressure, to obtain the fluorine-free waterproof sound-permeable membrane finished product; so that the film obtains the best physical and mechanical properties; S5. Testing and Verification: Test the waterproof, air permeability and acoustic performance of the finished fluorine-free waterproof and sound-permeable membrane to ensure that it meets high standards.

[0013] Preferably, in step S2, the weight of the nanospun membrane to be deposited is controlled to be between 2 and 20 g / m 2 ; The diameter morphology of the nanofibers is controlled to obtain nanofibers with a diameter of 200nm~3μm.

[0014] Preferably, by controlling the swing amplitude and swing speed of the array needle system of each module, a continuous and uniform nanospinning membrane with a width of up to 1 m is obtained.

[0015] Preferably, the voltage of the electrospinning device is 50 kV to 70 kV, the receiving distance is 20 cm to 40 cm, and the nozzle moving speed is 1.0 m / min to 3.0 m / min.

[0016] Preferably, in step S4, the adjustment temperature is 80°C to 160°C, the pressing time is 2s to 90s, the pressure is 0.05 to 0.5MPa, and the pressing gap is 0.1mm to 0.5mm.

[0017] Preferably, the fluorine-free waterproof sound-permeable membrane can rebound quickly within a few minutes after at least 5 rounds of hydrostatic pressure resistance test of withstanding a hydrostatic pressure of more than 20 KPa for 30 minutes.

[0018] A system for preparing the above-mentioned fluorine-free waterproof sound-permeable membrane includes a mixing system that can evenly configure the spinning solution, a large electrostatic spinning unit that can adjust various spinning parameters, and a post-processing device.

[0019] Preferably, the electrospinning unit for adjusting the spinning parameters further comprises a conveyor belt (11), a conveyor belt driving wheel (12), a receiving substrate (13), an unwinding wheel (14), a winding wheel (15), and an array needle (16).

[0020] In the above text, the cross-linking agent can form a cross-linking structure with the components containing active groups in the spinning solution, such as the polyurethane prepolymer in the polyurethane waterproofing agent, thereby enhancing the anti-aging properties and mechanical properties of the waterproof and sound-permeable membrane.

[0021] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. The present invention successfully prepared a safe and healthy product with good waterproof and breathable properties, high resilience, excellent acoustic performance and no fluorine through fine control of the selection of raw materials, the configuration of spinning solution, spinning process parameters and post-processing conditions; 2. The present invention not only improves the practical value of the product, but also provides new solutions for related industries and promotes the development of green and environmentally friendly materials. Especially for audio equipment manufacturers, this new material provides better audio consistency, less sound loss, and can quickly rebound and restore acoustic performance after being resistant to water pressure, thereby improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, some of the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be made based on these drawings without paying any creative work.

[0023] Figure 1 This is a scanning electron microscope image of the microporous fiber structure of the fluorine-free waterproof sound-permeable membrane of Example 1 of the present invention; Figure 2 This is the infrared spectrum of the organosilicon crosslinking agent before and after the crosslinking reaction of Example 1 of the present invention; Figure 3 This is a scanning electron microscope image of the fluorine-free waterproof sound-permeable membrane with a cross-linking agent of Example 1 of the present invention and the fluorine-free waterproof sound-permeable membrane without a cross-linking agent of Comparative Example 1 (after aging for 500 hours at 85°C and 85% relative humidity, scale = 5µm; the left image is the membrane without a cross-linking agent of Comparative Example 1, and the right image is the membrane with a cross-linking agent of Example 1); Figure 4 is a schematic diagram of an electrospinning unit in Example 1 of the present invention; Figure 5 Schematic diagram of the original state of the stretching and rebound test of the fluorine-free waterproof sound-permeable membrane of Example 1 of the present invention and the ePTFE membrane of Comparative Example 2; Figure 6 1 is a schematic diagram of a 10% rebound test of a fluorine-free waterproof sound-permeable membrane of Example 1 of the present invention and an ePTFE membrane of Comparative Example 2; Figure 7 20% stretch rebound test diagram of the fluorine-free waterproof sound-permeable membrane of Example 1 of the present invention and the ePTFE membrane of Comparative Example 2; Figure 8 Schematic diagram of the 30% stretch rebound test of the fluorine-free waterproof sound-permeable membrane of Example 1 of the present invention and the ePTFE membrane of Comparative Example 2; Fig. 9 This is a schematic diagram of the audio recovery test before and after the water pressure resistance of the fluorine-free waterproof sound-permeable membrane in Example 1 of the present invention; Among them, Figure 4 Middle: 11- conveyor belt, 12- conveyor belt driving wheel, 13- receiving substrate, 14- unwinding wheel, 15- rewinding wheel, 16- array needle head. DETAILED DESCRIPTION

[0024] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, a specific implementation scheme is now described in detail.

[0025] The present invention is further described below in conjunction with the examples, but the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not indicated are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0026] Example 1 See attached Figure 1-9 , this embodiment provides a fluorine-free waterproof sound-permeable membrane, which includes, by mass percentage: 35% fluorine-free polymer; 6% fluorine-free waterproof agent; 2% cross-linking agent; 57% solvent; Wherein, the fluorine-free waterproofing agent is an oily fluorine-free waterproofing agent, and the oily fluorine-free waterproofing agent is a polyurethane prepolymer and an alkyl ketene dimer; The fluorine-free polymer is polyurethane, polyacrylonitrile and polystyrene; The cross-linking agent is an organosilicon cross-linking agent, and the organosilicon cross-linking agent is N-β (aminoethyl) -γ-aminopropyltrimethoxysilane; The solvent is N'N-dimethylformamide, N'N-dimethylacetamide, and a mixed solvent of acetone and ethyl acetate, wherein the mass proportion of the amide solvent in the mixed solvent is 80%; The method for preparing the fluorine-free waterproof sound-permeable membrane comprises the following steps: S1. Preparation of spinning solution: Add the solvent into a stirring device, disperse the fluorine-free polymer and the fluorine-free waterproofing agent in the solvent, add the cross-linking agent thereto and stir to form a spinning solution, stir for 18 hours to make the spinning solution form a homogeneous system, and let it stand for 6 hours after stirring to discharge the bubbles in the spinning solution; S2, electrospinning: the spinning solution discharged from the bubbles in step S1 is added to the electrospinning device, and the liquid output of the nozzle is adjusted by controlling the liquid supply speed of each module of the electrospinning device, and the running speed of the conveyor belt used for collection is matched to control the gram weight of the deposited nanospinning membrane to 12g / m 2By controlling the size of the high-voltage electric field of the high-voltage system and the receiving distance between the spinning needle and the collecting area, the diameter morphology of the nanofibers is controlled to obtain nanofibers with a diameter of 800nm; by controlling the swing amplitude and swing speed of the array needle system of each module, a continuous and uniform nanospinning membrane with a width of up to 1m is obtained; S3, winding: the rolled nanospinning membrane substrate is used as a collecting auxiliary material and runs along the conveyor belt. After passing through the array needle system of each module, the nanofibers are evenly deposited on the nanospinning membrane substrate and enter the winding device; S4, post-processing: sending the received nanofiber nanospinning membrane to the post-processing equipment, adjusting the temperature to 120°C, the pressing time to 50s, the pressure to 0.25MPa, and the pressing gap to 0.3mm, to obtain the fluorine-free waterproof sound-permeable membrane finished product; so that the film obtains the best physical and mechanical properties; S5. Testing and Verification: Test the waterproof, air permeability and acoustic performance of the finished fluorine-free waterproof and sound-permeable membrane to ensure that it meets high standards.

[0027] The voltage of the electrospinning device is 60 kV, the receiving distance is 30 cm, and the nozzle moving speed is 2.0 m / min.

[0028] The system for preparing the above-mentioned fluorine-free waterproof sound-permeable membrane comprises a mixing system that can uniformly configure a spinning solution, a large electrospinning unit that can adjust various spinning parameters, and a post-processing device; the electrospinning unit for adjusting the spinning parameters also comprises a conveyor belt (11), a conveyor belt driving wheel (12), a receiving substrate (13), an unwinding wheel (14), a winding wheel (15), and an array needle (16).

[0029] Example 2 This embodiment provides a fluorine-free waterproof sound-permeable membrane, which includes, by mass percentage: 35% fluorine-free polymer; 8% fluorine-free waterproof agent; 2.5% cross-linking agent; 54.5% solvent; Wherein, the fluorine-free waterproofing agent is an oily fluorine-free waterproofing agent, and the oily fluorine-free waterproofing agent is a polyurethane prepolymer and an alkyl ketene dimer; The fluorine-free polymer is polyurethane, polyacrylonitrile and polystyrene; The cross-linking agent is an organosilicon cross-linking agent, and the organosilicon cross-linking agent is aminopropyltriethoxysilane (APTES); The solvent is N'N-dimethylformamide, N'N-dimethylacetamide, and a mixed solvent of acetone and ethyl acetate, wherein the mass proportion of the amide solvent in the mixed solvent is 80%; The method for preparing the fluorine-free waterproof sound-permeable membrane comprises the following steps: S1. Preparation of spinning solution: Add the solvent into a stirring device, disperse the fluorine-free polymer and the fluorine-free waterproofing agent in the solvent, add the cross-linking agent thereto and stir to form a spinning solution, stir for 18 hours to make the spinning solution form a homogeneous system, and let it stand for 6 hours after stirring to discharge the bubbles in the spinning solution; S2, electrospinning: the spinning solution discharged from the bubbles in step S1 is added to the electrospinning device, and the liquid output of the nozzle is adjusted by controlling the liquid supply speed of each module of the electrospinning device, and the running speed of the conveyor belt used for collection is matched to control the gram weight of the deposited nanospinning membrane to 12g / m 2 By controlling the size of the high-voltage electric field of the high-voltage system and the receiving distance between the spinning needle and the collecting area, the diameter morphology of the nanofibers can be controlled to obtain nanofibers with a diameter of 1000nm; by controlling the swing amplitude and swing speed of the array needle system of each module, a continuous and uniform nanospinning membrane with a width of up to 1m can be obtained; S3, winding: the rolled nanospinning membrane substrate is used as a collecting auxiliary material and runs along the conveyor belt. After passing through the array needle system of each module, the nanofibers are evenly deposited on the nanospinning membrane substrate and enter the winding device; S4, post-processing: sending the received nanofiber nanospinning membrane to the post-processing equipment, adjusting the temperature to 120°C, the pressing time to 50s, the pressure to 0.25MPa, and the pressing gap to 0.3mm, to obtain the fluorine-free waterproof sound-permeable membrane finished product; so that the film obtains the best physical and mechanical properties; S5. Testing and Verification: Test the waterproof, air permeability and acoustic performance of the finished fluorine-free waterproof and sound-permeable membrane to ensure that it meets high standards.

[0030] The voltage of the electrospinning device is 60 kV, the receiving distance is 30 cm, and the nozzle moving speed is 2.0 m / min.

[0031] The system for preparing the above-mentioned fluorine-free waterproof sound-permeable membrane comprises a mixing system that can uniformly configure a spinning solution, a large electrospinning unit that can adjust various spinning parameters, and a post-processing device; the electrospinning unit for adjusting the spinning parameters also comprises a conveyor belt (11), a conveyor belt driving wheel (12), a receiving substrate (13), an unwinding wheel (14), a winding wheel (15), and an array needle (16).

[0032] Comparative Example 1 See attached Figure 3 This comparative example is carried out on the basis of the above-mentioned embodiment 1, and the similarities with the above-mentioned embodiment are not repeated here.

[0033] In this comparative example, no cross-linking agent was added.

[0034] Comparative Example 2 See attached Figure 5-8 , this comparative example is an ePTFE membrane, (the ePTFE membrane is a product of Shanghai Jinyou Fluoro Materials Co., Ltd.).

[0035] The products of Examples 1-2 and Comparative Example 1 were tested, and the test results are shown in Table 1 (the air permeability is the double 85 test for 240 hours).

[0036] Table 1

[0037] As shown in Table 1, after 500 hours of double 85 test, the air permeability of the film product without cross-linking agent is only 284.7±11.93ml / min / cm²@7KPa, and the air permeability of the film product with added cross-linking agent is 3096±34.07ml / min / cm²@7Kpa; through the tensile test, the tensile strength of the film product with added cross-linking agent is 18.95MPa, and the tensile strength of the film product without cross-linking agent is only 8.69MPa.

[0038] Figure 2 Infrared spectra showed that there was no carbonyl peak in N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, and the carbonyl absorption peak of carbamate (1675.38cm-1) appeared in the substance formed after the cross-linking reaction with the polyurethane prepolymer in the waterproofing agent, indicating that the cross-linking reaction between isocyanate and amino group occurred after the addition of the diamino silicone cross-linking agent.

[0039] Figure 3 The scanning electron microscope image shows that after 500 hours of double 85 aging test, the fibers on the film product without adding cross-linking agent have aged and broken, while the fibers of the film product with cross-linking reaction have no obvious changes after the aging test.

[0040] In summary, the present invention successfully prepared a safe and healthy product with good waterproof and breathable properties, high resilience, excellent acoustic performance and no fluorine through fine control of the selection of raw materials, the configuration of spinning solution, the spinning process parameters and the post-processing conditions; the present invention not only improves the practical value of the product, but also provides a new solution for related industries and promotes the development of green and environmentally friendly materials. In particular, for audio equipment manufacturers, this new material provides better audio consistency, less sound loss, and can quickly rebound and restore acoustic performance after being resistant to water pressure, thereby improving the user experience.

[0041] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A fluorine-free waterproof sound-permeable membrane, characterized in that: Calculated by mass percentage, it includes: 30%~40% fluorine-free polymer; 4.5%~11.5% fluorine-free waterproofing agent; 0.5%~3.5% cross-linking agent; 45%~65% solvent; Wherein, the fluorine-free waterproofing agent is an oily fluorine-free waterproofing agent, and the oily fluorine-free waterproofing agent includes a polyurethane oily fluorine-free waterproofing agent and a long-chain alkane oily fluorine-free waterproofing agent; The fluorine-free polymers include polyurethane, polyacrylonitrile and polystyrene; The cross-linking agent is selected from one or more of an isocyanate cross-linking agent, an amino cross-linking agent, and an organosilicon cross-linking agent; The solvent is N'N-dimethylformamide, N'N-dimethylacetamide, and a mixed solvent of acetone and ethyl acetate, and the mass proportion of the amide solvent in the mixed solvent is 60% to 85%.

2. A method for preparing the fluorine-free waterproof sound-permeable membrane according to claim 1, characterized in that: The steps include: S1. Preparation of spinning solution: Put the solvent into a stirring device, disperse the fluorine-free polymer and the fluorine-free waterproofing agent in the solvent, add the cross-linking agent thereto and stir to form a spinning solution, stir for 12 to 20 hours to make the spinning solution form a homogeneous system, and let it stand for 3 to 6 hours after stirring to discharge the bubbles in the spinning solution; S2, electrospinning: adding the spinning solution from which the bubbles are discharged in step S1 into the electrospinning device, adjusting the liquid output of the nozzle by controlling the liquid supply speed of each module of the electrospinning device, and controlling the weight of the deposited nanospinning membrane by matching the running speed of the conveyor belt used for collection, and controlling the diameter and morphology of the nanofibers by controlling the size of the high-voltage electric field of the high-voltage system and the receiving distance between the spinning needle and the collecting area; obtaining a continuous and uniform nanospinning membrane by controlling the swing amplitude and swing speed of the array needle system of each module; S3, winding: the rolled nanospinning membrane substrate is used as a collecting auxiliary material and runs along the conveyor belt. After passing through the array needle system of each module, the nanofibers are evenly deposited on the nanospinning membrane substrate and enter the winding device; S4, post-processing: sending the received nanofiber nanospinning membrane to a post-processing device, adjusting the temperature, pressing time and pressure, to obtain the fluorine-free waterproof sound-permeable membrane finished product; S5. Testing and Verification: Test the waterproof performance, air permeability and acoustic performance of the finished fluorine-free waterproof and sound-permeable membrane to ensure that it meets high standards.

3. The method for preparing a fluorine-free waterproof sound-permeable membrane according to claim 2, characterized in that: In step S2, the weight of the nanospun membrane to be deposited is controlled to be between 2 and 20 g / m 2 ; The diameter morphology of the nanofibers is controlled to obtain nanofibers with a diameter of 200nm~3μm.

4. The method for preparing a fluorine-free waterproof sound-permeable membrane according to claim 2, characterized in that: In step S2, the swing amplitude and swing speed of the array needle system of each module are controlled to obtain a continuous and uniform nanospinning membrane with a width of up to 1 m.

5. The method for preparing a fluorine-free waterproof sound-permeable membrane according to claim 2, characterized in that: The voltage of the electrospinning equipment is 50 kV to 70 kV, the receiving distance is 20 cm to 40 cm, and the nozzle moving speed is 1.0 m / min to 3.0 m / min.

6. The method for preparing a fluorine-free waterproof sound-permeable membrane according to claim 2, characterized in that: In step S4, the adjustment temperature is 80°C to 160°C, the pressing time is 2s to 90s, the pressure is 0.05 to 0.5MPa, and the pressing gap is 0.1mm to 0.5mm.

7. The fluorine-free waterproof sound-permeable membrane according to claim 1, characterized in that: The polyurethane oily fluorine-free waterproofing agent is selected from one or more of polyurethane prepolymer, polyurethane modified oil, polyurethane acrylate, polyurethane modified epoxy resin and polyurethane silicone oil.

8. The fluorine-free waterproof sound-permeable membrane according to claim 1, characterized in that: The long-chain alkane oily fluorine-free waterproofing agent is selected from one or more of microcrystalline wax, polyethylene wax, oxidized polyethylene wax, Fischer-Tropsch wax, and alkyl ketene dimer.

9. A system for preparing the fluorine-free waterproof sound-permeable membrane as claimed in claim 1, characterized in that: It includes a mixing system for a spinning solution, an electrostatic spinning unit for adjusting spinning parameters, and a post-processing device.

10. The system for preparing a fluorine-free waterproof sound-permeable membrane according to claim 9, characterized in that: The electrospinning unit for adjusting spinning parameters further comprises a conveyor belt (11), a conveyor belt driving wheel (12), a receiving substrate (13), an unwinding wheel (14), a winding wheel (15), and an array needle (16).

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