A regular nanofiber membrane reinforced composite manufacturing process

Abstract

The present application relates to the technical field of nanofiber membrane, and particularly relates to a manufacturing process of regular nanofiber membrane reinforced composite material, comprising the following steps: S1, multi-field coupling electrospinning: a first high polymer is dissolved in a solvent to prepare a spinning solution, and a multi-field coupling electrospinning device is used to deposit a nanofiber layer on a receiving substrate; the field generated by the multi-field coupling electrospinning device includes a parallel electrostatic field and a periodic mechanical vibration force field; by adjusting the parameters of the field, the fiber diameter distribution deviation of the formed nanofiber layer is less than 15%, and the overall orientation degree of the fiber is greater than 75%; due to the high orientation and diameter uniformity of the nanofiber layer, the micropore channels formed thereby are more regular, which makes the acoustic impedance of the composite material in different batches perform highly consistently, provides a stable and reliable base material for acoustic adjustment of earphones, and can fine-tune the acoustic characteristics through the design of regularity.

Description

Technical Field

[0001] This invention relates to the field of nanofiber membrane technology, and more specifically to a manufacturing process for a regular nanofiber membrane reinforced composite material. Background Technology

[0002] In the field of consumer electronics, especially in precision acoustic devices such as high-fidelity headphones, acoustic mesh plays a crucial role. It is usually located in front of the receiver (speaker) unit, and its main functions are to prevent dust, water (sweat), and foreign objects from entering. At the same time, it must have precise acoustic damping characteristics to filter out noise with minimal interference without affecting the original sound quality. An ideal acoustic mesh needs to simultaneously meet the requirements of high breathability, excellent mechanical strength, long-term stable hydrophobic and stain-resistant ability, and a highly consistent microporous structure.

[0003] Currently, high-end acoustic meshes often use electrospun nanofiber membranes as the core functional layer because of their fine fiber diameter, high porosity, and controllable pore size distribution. However, existing technologies have the following significant drawbacks when applied to the specific application of headphones: I. Traditional electrospinning processes produce nanofibers that are mostly randomly stacked nonwoven fabric structures. The non-uniformity of fiber orientation and diameter distribution leads to differences in the mechanical properties and acoustic impedance of the membrane material in different regions, affecting the consistency of headphone sound and making it difficult to achieve precise acoustic tuning. II. To improve the strength of pure nanofiber membranes, common methods include overall impregnation with resin or composite with a base fabric. The former easily clogs the pores between nanofibers, significantly reducing air permeability and affecting acoustic performance, while the latter increases the overall thickness and rigidity, potentially altering acoustic characteristics and reducing wearing comfort. III. To impart hydrophobicity, a fluorine-containing coating is usually applied to the surface. These coatings are often quite thick (micrometer-level), significantly altering the pore structure and easily peeling off during use (e.g., due to sweat corrosion or friction), leading to the failure of protective functions. In view of this, we propose a manufacturing process for a regular nanofiber membrane-reinforced composite material. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings mentioned in the background art and provide a manufacturing process for regular nanofiber membrane reinforced composite materials.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A manufacturing process for a regular nanofiber membrane reinforced composite material includes the following steps: S1. Multi-field coupled electrospinning: A first polymer is dissolved in a solvent to prepare a spinning solution. A nanofiber layer is deposited on a receiving substrate using a multi-field coupled electrospinning device. The fields generated by the multi-field coupled electrospinning device include a parallel electrostatic field and a periodic mechanical vibration force field. By adjusting the parameters of the fields, the fiber diameter distribution deviation of the formed nanofiber layer is less than 15%, and the overall orientation degree of the fibers is greater than 75%. The multi-field coupled electrospinning device includes a high-voltage power supply, a liquid supply system, a spinneret assembly, a receiving device, and a mechanical vibration generator. The spinneret assembly is connected to the positive terminal of the high-voltage power supply to generate a spinning jet. The receiving device is connected to ground and is arranged parallel to the spinneret assembly to form a parallel electrostatic field between them. The mechanical vibration generator is mechanically coupled to the receiving device to drive the receiving device to perform periodic reciprocating vibration in a direction parallel to its surface, thereby forming the periodic mechanical vibration force field. By synergistically adjusting the field strength of the parallel electrostatic field and the frequency of the mechanical vibration, the well-arranged nanofibers can be effectively guided and solidified. In step S1 above, mechanical vibration applies regular disturbance to the jet, breaking the instability of the jet whipping and "guiding" and "arranging" it before solidification; the parallel electric field provides the jet with a clear and stable stretching and deposition direction; the synergistic effect of the two is equivalent to providing a "spatiotemporal template" for the formation of nanofibers, so that the jet is regularly arranged along the preset direction during the solidification process, thereby obtaining a nanofiber layer with uniform diameter and high orientation. This "regularity" is the precise structural basis for all subsequent enhancements and functionalizations, just like building a neat steel skeleton for a high-rise building; S2. In-situ semi-interpenetrating network reinforcement: The receiving substrate loaded with nanofiber layers obtained in step S1 is immersed in a solution of a second polymer prepolymer containing active functional groups, and then heat-treated at 40-80°C for 0.5-2 hours to allow the second polymer prepolymer to partially cross-link and solidify in the pores between the nanofibers, forming a semi-interpenetrating network structure, thereby obtaining a nanofiber composite membrane.

[0006] The "partial cross-linking curing" refers to the degree of cross-linking reaction of the prepolymer being controlled so that it forms a three-dimensional network structure and is anchored to the surface of the nanofibers, but does not completely fill all the pores between the fibers. This can be achieved by controlling the solid content of the prepolymer solution, the heat treatment temperature and time, and the ambient humidity. Preferably, the porosity of the composite membrane after treatment is maintained above 50%. In step S2 above, a prepolymer solution (low viscosity) containing active end groups (such as -NCO) is impregnated into the membrane. Due to the regular arrangement of fibers and good pore connectivity, the solution can uniformly penetrate the entire fiber network through capillary action, rather than just remaining on the surface. Under controlled heat / humidity conditions, the prepolymer undergoes a partial cross-linking reaction to form a polymer network. This network grows and anchors on the surface of the nanofibers and around their interlacing points, but does not completely fill all the pores, nor does it form a dense encapsulation layer. Finally, the rigid nanofiber skeleton and the flexible in-situ generated resin network penetrate, entangle, and anchor each other. The resin network, like "concrete," reinforces the connection points of the "steel" skeleton, greatly improving the overall structural integrity (strength) while retaining the permeability (breathability) of the pores. This is the key difference from simple impregnation and coating, achieving reinforcement without clogging the pores. S3. Functionalized interface treatment: The nanofiber composite membrane obtained in step S2 is placed in a plasma treatment device and surface treatment is performed under low pressure using a fluorine-containing process gas. The treatment power is 50-300W and the treatment time is 10-120 seconds, thereby forming a nano-thickness hydrophobic and oleophobic modified layer on the surface of the nanofiber composite membrane, thus obtaining a regular nanofiber membrane reinforced composite material. In step S3 above, high-energy particles (ions, electrons, and active free radicals) in the plasma bombard the material surface, while fluorine-containing gases (such as...) are also present. The decomposition of these compounds generates a large number of fluorocarbon free radicals; these reactive species react with the polymer chains on the outermost layer (several to tens of nanometers deep) of the composite material, grafting fluorocarbon groups onto them in the form of covalent bonds. , (etc.), thereby significantly reducing surface energy; this process only changes the surface chemical properties at the nanoscale, with almost no increase in physical thickness, so it has zero impact on the carefully designed pore structure. Since the modified layer is a molecular-level graft, rather than a physically adsorbed coating, it has excellent abrasion and solvent resistance, and its function is long-lasting and stable.

[0007] Preferably, in step S1, the field strength of the parallel electrostatic field is 0.8-1.5 kV / cm, and the frequency of the periodic mechanical vibration force field is 100-300 Hz. Coordinating and controlling these parameters within this range is more conducive to obtaining a nanofiber layer with a fiber diameter distribution deviation of less than 12% and an orientation degree of more than 80%.

[0008] Preferably, in step S1, the spinneret in the multi-field coupled electrospinning device is a spinning needle with one or more metal needles.

[0009] Preferably, in step S1, the first polymer is one of thermoplastic polyurethane, polyvinylidene fluoride, polyacrylonitrile, or polyamide; and the solvent is N,N-dimethylformamide, tetrahydrofuran, acetone, or a mixture thereof.

[0010] Preferably, in step S1, the frequency of the periodic mechanical vibration force field is 50-500 Hz, and the field strength of the parallel electrostatic field is 0.8-1.5 kV / cm; the receiving substrate is a non-woven fabric, a porous film, or a continuously rotating metal roller.

[0011] Preferably, in step S2, the second polymer prepolymer containing active functional groups is one of a polyurethane prepolymer, an epoxy resin prepolymer, or an acrylate prepolymer with isocyanate (-NCO) end groups; the solid content of the prepolymer solution is 5%-20% (by weight).

[0012] Preferably, when the second polymer prepolymer is a polyurethane prepolymer, the heat treatment in step S2 is carried out in an environment with a relative humidity of 30%-70%, so that the prepolymer reacts simultaneously with the trace moisture on the surface of the nanofiber and its own active groups.

[0013] Preferably, in step S3, the fluorine-containing process gas used in the plasma treatment is at least one of carbon tetrafluoride, sulfur hexafluoride, or trifluoromethane, and the gas pressure is 10-50 Pa.

[0014] A regular nanofiber membrane reinforced composite material, comprising: Nanofiber framework, wherein the nanofiber framework is a layer of nanofibers with a regularly oriented structure; A reinforcing resin, formed from a second polymer, permeates and partially cross-links in the pores of the nanofiber skeleton, and the reinforcing resin and the nanofiber skeleton form a semi-interpenetrating network structure. A hydrophobic and oleophobic modified layer is applied to the surface of the nanofiber composite membrane.

[0015] Preferably, the composite material has a thickness of 10-100 micrometers, a porosity of 40%-70%, a water contact angle greater than 120°, and an oil contact angle greater than 90°.

[0016] An acoustic mesh, made of a regularly spaced nanofiber membrane-reinforced composite material, is used for acoustic damping and dust protection in front of the receiver unit of an earphone.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. Due to the high orientation and diameter uniformity of the nanofiber layer, the micropore channels formed are more regular, which makes the acoustic impedance performance of the composite material highly consistent in different batches. This provides a stable and reliable basic material for headphone acoustic tuning, and the acoustic characteristics can be fine-tuned by designing the "regularity" (such as orientation angle). 2. By forming a Semi-IPN structure in situ, "spot welding" reinforcement is carried out at the key nodes of nanofibers, which increases the tensile strength and tear strength of the composite material (especially along the fiber orientation direction) by several times, while the effective porosity is preserved to the maximum extent (usually >60%). The resulting acoustic mesh is both strong and durable, and can ensure low sound loss transmission. 3. Through low-temperature plasma surface grafting technology, it is endowed with excellent superhydrophobic and oil-resistant properties (water contact angle >120°) without changing the material geometry and breathability. This functional layer is chemically bonded and is resistant to sweat, sebum erosion and daily friction, which can ensure that the sound quality of the headphones is not affected by pollution for a long time and extend the product's service life. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The present invention will describe the above technical solution in detail through the following embodiments: Example 1 A manufacturing process for a regular nanofiber membrane reinforced composite material includes the following steps: S1. Multi-field coupled needle electrospinning: Thermoplastic polyurethane (TPU, model 1185A) was dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) (volume ratio 1:1) to prepare a 12 wt% spinning solution. A multi-field coupled electrospinning device was used, which was equipped with a stainless steel needle with an inner diameter of 0.6 mm as a spinneret. The spinneret was connected to an 18 kV positive high voltage, and the receiving roller was grounded. It was connected to an eccentric motor-type mechanical vibrator through a drive shaft, which made it vibrate in the horizontal direction. The parallel electrostatic field strength was set to 1.2 kV / cm, the frequency of the mechanical vibrator connected to the receiving roller was 200 Hz, the receiving substrate was polyester (PET) nonwoven fabric, the receiving distance was 18 cm, and spinning was carried out for 2 hours to obtain a TPU nanofiber layer with regular orientation. S2, In-situ semi-interpenetrating network reinforcement: The polyurethane prepolymer (-NCO content 5.5%) was diluted with ethyl acetate to a 10wt% solution. The TPU nanofiber layer obtained in step S1 was completely immersed for 30 seconds and then removed. Excess solution on the surface was scraped off and placed in an oven at 60℃ and 50% relative humidity for 1 hour to obtain a nanofiber composite film. S3. Functionalized interface treatment: The nanofiber composite membrane obtained in step S2 is placed in the chamber of a plasma treatment device, carbon tetrafluoride is introduced, the pressure is maintained at 30 Pa, and it is treated with 150 W radio frequency power for 60 seconds to obtain a regular nanofiber membrane reinforced composite material.

[0020] Example 2 The only difference between this embodiment and Embodiment 1 is that in step S1 of this embodiment, the first polymer is replaced with polyvinylidene fluoride (PVDF), the solvent is a mixture of N,N-dimethylformamide (DMF) and acetone (volume ratio 7:3) with a concentration of 10 wt%, and all other conditions are the same.

[0021] Example 3 The only difference between this embodiment and Embodiment 1 is that in step S2 of this embodiment, the second polymer prepolymer containing active functional groups is replaced with an epoxy resin prepolymer (E-44 type), the curing agent is polyamide 650, the mass ratio is 10:3, it is diluted with acetone to a solution with a total solid content of 15%, and the heat treatment conditions are 80°C for 1.5 hours, while all other conditions are the same.

[0022] Example 4 The only difference between this embodiment and embodiment 1 is that in step S3 of this embodiment, the plasma processing gas is replaced with a mixture of sulfur hexafluoride and argon (volume ratio 1:4), the processing power is 100 W, and the processing time is extended to 90 seconds, while all other conditions remain the same.

[0023] Example 5 The only difference between this embodiment and Embodiment 1 is that in step S1 of this embodiment, the process parameters are adjusted to change the fiber regularity, the parallel electrostatic field strength is set to 0.9 kV / cm, the mechanical vibration frequency is 100 Hz, and all other conditions are the same.

[0024] Comparative Example 1 The only difference between this comparative example and Example 1 is that in step S1 of this comparative example, the mechanical vibrator is turned off, and only a parallel electrostatic field is used for electrospinning. The resulting nanofibers have a random structure. The subsequent reinforcement and processing steps are the same as in Example 1, and all other conditions are the same.

[0025] Comparative Example 2 The only difference between this comparative example and Example 1 is that step S2 (in-situ semi-interpenetrating network reinforcement) is omitted in this comparative example, and the pure TPU nanofiber layer prepared in Example 1 is directly subjected to the same plasma treatment as in Example 1, while all other conditions are the same.

[0026] Comparative Example 3 The only difference between this comparative example and Example 1 is that in step S2 of this comparative example, instead of using a prepolymer solution, a fully cured polyurethane (PU) resin solution (solid content 25%) is impregnated and then fully cured at 80°C. This method results in the resin completely coating the fiber and filling most of the pores. The subsequent treatment is the same as in Example 1, and all other conditions are the same.

[0027] Comparative Example 4 The only difference between this comparative example and Example 1 is that in step S3 of this comparative example, the process gas used for plasma treatment is pure oxygen, while other parameters remain unchanged. Oxygen plasma will make the material surface hydrophilic, and other conditions are the same.

[0028] Comparative Example 5 The only difference between this comparative example and Example 1 is that in step S3 of this comparative example, plasma treatment is not performed. Instead, a commercial fluorinated hydrophobic agent is coated on the surface of the nanofiber composite membrane by spraying. The dry film thickness is about 2-3 micrometers. All other conditions are the same.

[0029] Samples were prepared according to Examples 1-5 and Comparative Examples 1-5 above, and the following tests were performed: 1. Fiber morphology and structural characterization tests: Test items: fiber diameter and distribution, orientation, and microstructure; Test procedure: After gold sputtering, the surface morphology is observed using a scanning electron microscope (SEM, such as Hitachi SU8010) at an accelerating voltage of 10 kV. The diameter of at least 100 fibers is randomly measured using image analysis software (such as ImageJ), and the mean and standard deviation are calculated. The SEM images are analyzed using the Fourier transform (FFT) plugin of the software to calculate the fiber orientation degree (0-100%, the higher the value, the more consistent the orientation).

[0030] 2. Mechanical property testing: Test items: tensile strength, elongation at break; Test procedure: Cut the sample into dumbbell-shaped standard specimens (such as GB / T 1040.3-2006 Type 1BA), use a universal testing machine (such as Instron 5967) to test at a tensile speed of 50 mm / min, and record the maximum tensile strength (MPa) and elongation at break (%). At least 5 parallel samples should be tested for each sample.

[0031] 3. Air permeability and porosity performance test: Test items: air permeability, porosity; Test process: Air permeability: Using a digital fabric air permeability tester (such as YG461E), according to GB / T 5453-1997 standard, the test area is 20 cm². 2 The air transmittance (mm / s) was measured under a pressure difference of 100 Pa. Porosity: The volume (V) of the sample is calculated by measuring its geometric dimensions using a weighing method, and the weight (M) is measured precisely. The porosity ε is calculated based on the material density (ρ) as follows: ε = (1 - M / (ρV)) × 100%.

[0032] 4. Surface performance testing: Test items: water contact angle, oil contact angle, durability.

[0033] Test process: Contact angle: Using a contact angle measuring instrument (such as Dataphysics OCA20), the static drop method is used. 5 μL of deionized water or hexadecane oil is dropped onto the sample surface, and the static contact angle (°) is measured. 5 points are measured for each sample and the average is taken. Durability: The water contact angle is measured again after subjecting the sample surface to a certain number of abrasion tests (e.g., 500 times) using a standard abrasion tester (e.g., Martindale) or after immersing it in artificial sweat (prepared according to ISO 3160-2) for 24 hours.

[0034] 5. Acoustic performance testing: Test item: Acoustic impedance; Test Procedure: Using an impedance tube (such as the B&K 4206 series) and the two-microphone transfer function method, measure the normal incident acoustic impedance (Pa·s) of the sample at a key frequency point (such as 1 kHz) according to ISO 10534-2 standard. Multiple samples were tested to assess consistency.

[0035] The specific data is shown in Table 1 below: Table 1 As can be seen from the data in Table 1 above, the two data points of "small diameter distribution deviation" (±25 nm) and "high orientation degree" (82%) of Example 1 are direct and measurable evidence that it is called a "regular" nanofiber membrane, which is the structural basis for its ability to achieve consistent acoustic performance and efficient enhancement.

[0036] The data from Comparative Example 1 provides the most direct comparison. After the mechanical vibration field was turned off, despite other conditions being the same, the orientation degree plummeted to below 10%, the diameter distribution widened, and the structure became completely random. This irrefutably proves that the coupling of the "parallel electrostatic field" and the "periodic mechanical vibration force field" is a necessary and sufficient condition for creating regular fiber structures, rather than something that can be achieved by a single electric field.

[0037] The fiber diameter and orientation data of Example 3 are similar to those of Example 1, indicating that the in-situ semi-interpenetrating network (Semi-IPN) reinforcement did not destroy the already formed regular fiber skeleton. However, the conventional impregnation method used in Comparative Example 3 caused the fiber morphology to disappear completely, which intuitively explains why its air permeability dropped sharply - the reinforcement method is completely different.

[0038] The intermediate product (NF-SIPN-1) of Example 1 and Comparative Example 4 before plasma treatment has the same structure. After treatment, the fiber morphology data (diameter, orientation degree) of the two remain consistent. This proves that neither carbon tetrafluoride nor pure oxygen plasma treatment under the parameters of the present invention damages or changes the microscopic physical structure of the material. The functional difference (superhydrophobic vs. hydrophilic) is entirely due to the surface chemical modification at the nanoscale, rather than the morphological change. This highlights the precision and non-invasiveness of the functionalization steps of the present invention.

[0039] The data from Comparative Example 5 show that traditional spraying methods form an additional physical coating on the fiber surface, which directly changes the most critical structure of the composite material—the pores and fiber surface—making its morphology impossible to observe accurately, and consequently causing problems such as reduced air permeability and poor durability.

[0040] The specific data is shown in Table 2 below: Table 2 As shown in Table 2 above, the tensile strength along the main fiber orientation of Example 1 is 14.0 MPa and the elongation at break is 175%, while the strength of Comparative Example 2, which is not reinforced, is only 4.5 MPa.

[0041] The results of Comparative Example 1 without a mechanical vibration field offer fundamental insights. Using only a parallel electrostatic field, Comparative Example 1 yielded a completely random fiber structure. Although it underwent the same reinforcement and hydrophobic treatment, the final product exhibited significant shortcomings in tensile strength and acoustic impedance consistency. Compared to Example 1, its strength decreased by approximately 40%, and the fluctuation range of acoustic impedance increased. This demonstrates that "regularity" is not a vague concept, but rather a quantifiable and reproducible structural characteristic. The fiber skeleton with an orientation greater than 75%, generated by the coupling of mechanical vibration and a parallel electric field, acts like a neat network of "reinforcing bars" in reinforced concrete for the composite material. This regular structure not only possesses higher mechanical efficiency (anisotropic strength), but more importantly, it provides a perfect foundation for the uniform penetration of subsequent reinforcing resin and the uniform plasma treatment, thus ensuring the high uniformity and stability of the final product's performance. This is the physical basis for achieving the "consistency" requirements of high-end acoustic devices.

[0042] Example 1 had an air permeability of 345 mm / s and a porosity of 65%. Comparative Example 3 used conventional impregnation, which resulted in a sharp drop in air permeability to 85 mm / s and a porosity of 28%.

[0043] Comparative Example 2 directly exposes the inherent weaknesses of pure nanofiber membranes: extremely low strength and poor practicality; its strength is less than one-third of that of Example 1, and the fragile fibers lacking resin protection are easily damaged in subsequent processing and actual use; Comparative Example 3, with its conventional resin impregnation, represents a conventional reinforcement approach. Although the strength is improved, its air permeability drops sharply by more than 70%, and the porosity is severely blocked, which perfectly confirms the "contradiction between strength and air permeability" pointed out in the background art.

[0044] In contrast, Example 1 utilizes a semi-interpenetrating network formed through in-situ and partial cross-linking to achieve "spot welding" reinforcement at key nodes of the nanofibers, rather than "integral casting." This allows for a nearly three-fold increase in strength while successfully maintaining over 65% air permeability. The fundamental difference in this reinforcement mechanism lies in the fact that traditional impregnation sacrifices porosity for strength, while the Semi-IPN of this invention precisely enhances strength while protecting porosity. The failures of Comparative Examples 2 and 3 demonstrate, from both positive and negative perspectives, that the Semi-IPN reinforcement step is the core innovation and irreplaceable element of this invention.

[0045] In Example 1, the water contact angle was >155° and remained >150° after friction. In Comparative Example 4, the process gas used in plasma treatment was pure oxygen, and the water contact angle was <30° (hydrophilic). In Comparative Example 5, a commercial fluorinated hydrophobic agent was coated on the surface of the nanofiber composite membrane by spraying. The initial hydrophobicity was good, but the coating fell off after friction, and the contact angle decreased significantly.

[0046] Comparative Example 4 yielded a completely hydrophilic surface. This result dramatically demonstrates that plasma treatment itself is a "double-edged sword." The choice of process gas directly determines the success or failure of the function. Oxygen treatment introduces polar groups, which violates the fundamental requirement of earphone mesh to be sweat-proof and stain-resistant. This proves that fluorinated gas is the only correct technical direction for achieving the goal of durable hydrophobicity and oleophobicity.

[0047] Although Comparative Example 5 showed good initial hydrophobicity, it had extremely poor abrasion resistance, the coating was easy to peel off, and the micron-sized coating significantly reduced the air permeability. This reflects the inherent defects of physical coatings: weak adhesion, impact on structure, and insufficient durability.

[0048] The fluorine-containing gas plasma treatment used in Example 1 is a nanoscale gas-solid phase reaction grafting. It grafts low-surface-energy fluorocarbon groups onto the outermost layer of the material through strong chemical bonds, without increasing thickness or clogging pores. Therefore, it not only achieves superhydrophobicity but, more importantly, realizes a long-life fusion of function and structure—the air permeability remains unchanged after treatment, while also exhibiting wear and corrosion resistance. This step upgrades "protection" from a easily worn "coating" to an inherent "property" of the material.

[0049] Example 1 has an acoustic impedance of 182 ± 20 Pa at 1 kHz. The small standard deviation indicates high consistency, while the impedance value of the random fiber in Comparative Example 1 fluctuates within a large range.

[0050] Examples 2 and 3 show that the specific types of the first and second polymers can be selected within a certain range according to performance emphasis (such as higher strength, different chemical resistance), proving that the present invention protects a process principle platform, rather than a single material formulation.

[0051] Examples 4 and 5 show that the process parameters can be adjusted within a certain range to still achieve superior performance compared to the comparative examples. For example, although Example 5 is slightly inferior to Example 1, it still completely surpasses all the comparative examples. This proves that the process of the present invention has a good operability window and robustness, which is conducive to the stable implementation of industrial production.

[0052] Based on the data in the table above, Example 1 is preferred.

[0053] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A manufacturing process for a regular nanofiber membrane reinforced composite material, characterized in that, Includes the following steps: S1. Multi-field coupled electrospinning: A first polymer is dissolved in a solvent to prepare a spinning solution. A nanofiber layer is deposited on a receiving substrate using a multi-field coupled electrospinning device. The fields generated by the multi-field coupled electrospinning device include a parallel electrostatic field and a periodic mechanical vibration force field. By adjusting the parameters of the fields, the fiber diameter distribution deviation of the formed nanofiber layer is less than 15%, and the overall orientation degree of the fibers is greater than 75%. S2. In-situ semi-interpenetrating network reinforcement: The receiving substrate loaded with nanofiber layer obtained in step S1 is immersed in a solution of a second polymer prepolymer containing active functional groups, and then heat-treated at 40-80℃ for 0.5-2 hours to allow the second polymer prepolymer to partially cross-link and solidify in the pores between nanofibers, forming a semi-interpenetrating network structure, thereby obtaining a nanofiber composite membrane. S3. Functionalized interface treatment: The nanofiber composite membrane obtained in step S2 is placed in a plasma treatment device and surface treatment is performed under low pressure using a fluorine-containing process gas. The treatment power is 50-300W and the treatment time is 10-120 seconds, thereby forming a nano-thickness hydrophobic and oleophobic modified layer on the surface of the nanofiber composite membrane, thus obtaining a regular nanofiber membrane reinforced composite material.

2. The manufacturing process of the regular nanofiber membrane reinforced composite material as described in claim 1, characterized in that: In step S1, the spinneret in the multi-field coupled electrospinning device is a spinning needle with one or more metal needles.

3. The manufacturing process of the regular nanofiber membrane reinforced composite material as described in claim 1, characterized in that: In step S1, the first polymer is one of thermoplastic polyurethane, polyvinylidene fluoride, polyacrylonitrile, or polyamide; the solvent is N,N-dimethylformamide, tetrahydrofuran, acetone, or a mixture thereof.

4. The manufacturing process of the regular nanofiber membrane reinforced composite material as described in claim 1, characterized in that: In step S1, the frequency of the periodic mechanical vibration force field is 50-500 Hz, and the field strength of the parallel electrostatic field is 0.8-1.5kV / cm; the receiving substrate is non-woven fabric, porous film, or continuously rotating metal roller.

5. The manufacturing process of the regular nanofiber membrane reinforced composite material as described in claim 1, characterized in that: In step S2, the second polymer prepolymer containing active functional groups is one of a polyurethane prepolymer, an epoxy resin prepolymer, or an acrylate prepolymer with isocyanate end groups; the solid content of the prepolymer solution is 5%-20%.

6. The manufacturing process of the regular nanofiber membrane reinforced composite material as described in claim 5, characterized in that: When the second polymer prepolymer is a polyurethane prepolymer, the heat treatment in step S2 is carried out in an environment with a relative humidity of 30%-70%, so that the prepolymer reacts simultaneously with the trace moisture on the surface of the nanofiber and its own active groups.

7. The manufacturing process of the regular nanofiber membrane reinforced composite material as described in claim 1, characterized in that: In step S3, the fluorine-containing process gas used in the plasma treatment is at least one of carbon tetrafluoride, sulfur hexafluoride, or trifluoromethane, and the gas pressure is 10-50 Pa.

8. A regular nanofiber membrane reinforced composite material obtained by the manufacturing process according to any one of claims 1 to 7, characterized in that, include: Nanofiber framework, wherein the nanofiber framework is a layer of nanofibers with a regularly oriented structure; A reinforcing resin, formed from a second polymer, permeates and partially cross-links in the pores of the nanofiber skeleton, and the reinforcing resin and the nanofiber skeleton form a semi-interpenetrating network structure. A hydrophobic and oleophobic modified layer is applied to the surface of the nanofiber composite membrane.

9. The regular nanofiber membrane reinforced composite material as described in claim 8, characterized in that: The composite material has a thickness of 10-100 micrometers, a porosity of 40%-70%, a water contact angle greater than 120°, and an oil contact angle greater than 90°.

10. An acoustic mesh, characterized in that, It is made of the regular nanofiber membrane reinforced composite material according to any one of claims 7 to 8, and is used for acoustic damping and dust protection in front of the earphone receiver unit.

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