Non-woven fabric for filter

Abstract

The invention discloses a filter non-woven fabric. The filter non-woven fabric comprises a surface layer, a middle layer and a bottom layer which are sequentially stacked, wherein the surface layer is a fine filtering layer and is prepared by electrostatic spinning of nanofibers; the middle layer is arranged as a main filter layer and is prepared from high-efficiency electret melt-blown polypropylene; the bottom layer is a supporting layer and is made of spun-bonded polyester; the surface density is set to be 0.3-0.8 g / m, and the thickness is set to be 5-15 microns, so that a superfine limiting network is formed; the surface density of the middle layer is set to be 15-30 g / m, the thickness of the middle layer is set to be 0.3-0.6 mm, and an electret adopts fluoridation treatment and a corona electret; the surface density of the bottom layer is 20-40g / m, and the thickness of the bottom layer is 0.15-0.3 mm. According to the non-woven fabric for the filter, the nanofibers are directly deposited on the melt-blown layer through one-step online compounding, then the spun-bonded bottom layer is compounded through hot pressing, production steps are reduced, the interlayer binding force is enhanced, meanwhile, the nanofibers are only compounded on the surface layer of the filter material, and the cost can be greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-woven fabrics, in particular to a filter non-woven fabric. BACKGROUND

[0002] Non-woven fabric is a kind of sheet or flocculent material formed by directly orienting or randomly arranging fibers into a network structure through physical, chemical or mechanical methods, and then forming it by reinforcement (such as thermal bonding, chemical bonding, mechanical entanglement, etc.). Its essence is "fiber assembly" rather than "yarn interweave". The existing non-woven fabric product has the characteristics of short process flow, strong structure designability, diverse raw materials and flexible performance, and can adjust the production process according to the actual application scene to obtain a non-woven fabric product with target physical and chemical properties. Compared with traditional textiles, non-woven fabric forms a random fiber network by directly forming a network of fibers, which can be designed to be isotropic or anisotropic according to demand. For filter, filter non-woven fabric is a kind of high-efficiency filter material for separating impurities in gas or liquid by physical interception, electrostatic adsorption and other methods, which is made of synthetic fibers (such as polypropylene and polyester) by melt blowing, spun-bonding, needle punching and other processes. Its core feature is to have a three-dimensional network porous structure, with high air permeability, high dust holding capacity and customizable function.

[0003] However, in the existing filter non-woven fabric product, the charge storage capacity and environmental stability of the traditional corona and electrostatic filter material are insufficient, which leads to problems such as significant charge decay of non-woven fabric in high temperature and high humidity environment, sudden drop of PM0.3 filtration efficiency, etc. SUMMARY

[0004] Therefore, it is necessary to provide a filter non-woven fabric to solve the technical problem of insufficient charge storage capacity and environmental stability of the traditional corona and electrostatic filter material.

[0005] A filter non-woven fabric, which comprises a surface layer, an intermediate layer and a bottom layer arranged in sequence; wherein the surface layer is arranged as a fine filter layer and is made of electrospun nanofibers; the intermediate layer is arranged as a main filter layer and is made of high-efficiency electrostatic melt-blown polypropylene; and the bottom layer is arranged as a support layer and is made of spun-bonded polyester.

[0006] The surface layer fibers have a diameter of 80-200 nm, an areal density of 0.3-0.8 g / m², and a thickness of 5-15 μm, forming an ultrafine confinement network that provides high initial efficiency and low surface deposition. The intermediate layer fibers have a diameter of 1-3 μm, an areal density of 15-30 g / m², and a thickness of 0.3-0.6 mm. The electret is fluorinated and corona-electreted to ensure high charge stability and high efficiency with low resistance in the intermediate layer. The bottom layer fibers have a diameter of 15-25 μm, an areal density of 20-40 g / m², and a thickness of 0.15-0.3 mm, ensuring high mechanical strength and airflow dispersion capabilities while providing protection to the intermediate layer, which is also the main filter layer.

[0007] The filter nonwoven fabric is produced using the following steps: raw material preparation, including a predetermined amount of PP chips, PET chips, and functional masterbatch; bottom layer production, producing spunbond PET that meets predetermined parameter standards for online lamination; intermediate layer production, producing a PP meltblown layer containing a predetermined amount of fluorinated electret masterbatch, followed by online electrospinning to obtain a nanofiber surface layer on the surface of the intermediate layer; lamination, online lamination of the prepared intermediate layer with the surface layer to the bottom layer, and hot air penetration bonding to obtain the nonwoven fabric; online synergistic electret treatment of the nonwoven fabric through corona and water mist polarization; functional post-treatment of the nonwoven fabric, adding additional functions to the nonwoven fabric according to product requirements; drying, slitting, and winding the nonwoven fabric, followed by ultrasonic edge reinforcement to obtain the finished filter nonwoven fabric.

[0008] In one embodiment, the aforementioned surface nanofibers are made of either PET or PA6.

[0009] In one embodiment, the aforementioned surface layer also contains 0.5-2% functional additives.

[0010] In one embodiment, the functional additives for the surface layer are one or more of the following functional additives: quaternary ammonium salt antibacterial agents, silver-based antibacterial agents, and fluorocarbon hydrophobic agents.

[0011] In one embodiment, the fluorinated electret masterbatch in the above-mentioned intermediate layer production process uses 5% PTFE nanoparticles.

[0012] In one embodiment, the aforementioned intermediate layer also contains 30% activated carbon powder.

[0013] In one embodiment, the aforementioned substrate also contains 1-3% hydrophilic modifier.

[0014] In one of the embodiments, the surface layer thickness described above can be set to 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm.

[0015] In one of the embodiments, the surface layer area density described above can be set to 0.3 g / m², 0.4 g / m², 0.5 g / m², 0.6 g / m², 0.7 g / m² or 0.8 g / m² In one of the embodiments, the intermediate layer thickness described above can be set to 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm or 0.6 mm.

[0016] In one of the embodiments, the intermediate layer area density described above can be set to 15 g / m², 20 g / m², 25 g / m² or 30 g / m².

[0017] In one of the embodiments, the bottom layer thickness described above can be set to 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm.

[0018] In one of the embodiments, the bottom layer area density described above can be set to 20 g / m², 25 g / m², 30 g / m², 35 g / m² or 40 g / m².

[0019] In one of the embodiments, the filter non-woven fabric described above is produced by the following steps: S1, a predetermined amount of PP, PET chip is dehydrated in an 80℃ oven for 4 hours (moisture content ≤ 50ppm); S2, intermediate layer raw material pretreatment: PP chip, 5% fluorine-containing polar mother particles and 30% activated carbon powder are fully mixed; S3, surface layer raw material pretreatment: PET is dissolved in hexafluoroisopropyl alcohol (concentration 12wt%), 0.8% quaternary ammonium salt antibacterial agent is added and fully mixed S4, based on Reicofil4 type spunbond line, under the process conditions of PET melt temperature 290℃, spinning speed 3500m / min, air flow drafting pressure 0.25MPa, web forming speed 100m / min, output area density 25g / m², thickness 0.2mm PET spunbond fabric; S5, melt blowing / nanofiber online compounding, based on double row spinneret (pore diameter 0.3mm), air gap 1.0mm, melt blowing processing of the intermediate layer is carried out; then based on multi-needle array (100 needles / m), electrospinning treatment of the surface of the intermediate layer is carried out 20 cm below the melt blowing die, when the melt blowing fiber has not completely solidified, the nanofiber is directly deposited on the surface to form physical entanglement, so as to realize the online compounding of melt blowing / nanofiber, and the composite structure of the intermediate layer and the surface layer is obtained; S6, based on the bottom layer (PET spun-bond layer) → middle layer (PP melt-blown) / surface layer (nanofiber layer) layering order, hot air penetration bonding of the three-layer structure is completed at a hot air temperature of 145℃, an air speed of 2.5m / s, a penetration time of 8s, and a cooling roller temperature of 20℃, to obtain a non-woven fabric; S7, the non-woven fabric is subjected to double-section synergistic electret treatment, section 1 is subjected to corona discharge treatment under the conditions of a voltage of ±30kV, an electrode spacing of 10mm, and a fabric walking speed of 10m / min, and section 2 is subjected to water mist polarization treatment under the conditions of a misting liquid of deionized water + 0.1% isopropyl alcohol, a water pressure of 0.3MPa, a mist droplet particle size of 5-10μm, and a polarization voltage of +15kV; S8, the non-woven fabric is subjected to functional post-treatment, including hydrophobic treatment: the bottom layer is immersed in 5% fluorocarbon emulsion with a pick-up rate of 80%; antibacterial treatment: the surface layer is sprayed with 0.5% quaternary ammonium salt solution and microwave cured; and hydrophilic treatment: the bottom layer is immersed in 3% polyethylene glycol derivative; S9, the non-woven fabric is subjected to drying and laser slitting; S10, the non-woven fabric is subjected to edge reinforcement based on an ultrasonic welding machine under the conditions of a frequency of 20kHz, a pressure of 0.4MPa, and a welding width of 3mm, to obtain a filter non-woven fabric product; S11, the product is wound and packaged in an electrostatic aluminum foil bag.

[0020] In summary, the filter non-woven fabric of the present application has the following advantages: (1) nanofibers are directly deposited on the melt-blown layer by one-step online compounding, and the spun-bond bottom layer is hot-pressed and compounded, reducing production steps and enhancing interlayer bonding force, and at the same time, only nanofibers are compounded on the surface layer of the filter material, which can significantly reduce costs; (2) the addition of fluorine-containing electret masterbatch in the PP melt-blown raw material significantly improves the charge storage capacity and environmental stability, and the combination of corona discharge and water mist polarization in the production process produces a more uniform and stable bipolar charge layer; (3) hot air penetration bonding is used instead of traditional hot rolling point bonding, providing overall uniform bonding with small porosity loss, making the non-woven fabric more fluffy and soft, and having a higher dust holding capacity, and the ultrasonic edge reinforcement treatment reinforces the edges of the filter material, which can effectively prevent the non-woven fabric from delaminating during use. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of the filter non-woven fabric in one embodiment. DETAILED DESCRIPTION

[0022] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the specific embodiments of the present application will be described below in detail with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in many different ways from what is described herein, and should not be construed as being limited to the embodiments set forth herein, but should be understood to include all possible embodiments.

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the purpose of facilitating the description of the present application and simplifying the description, and therefore should not be construed as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application.

[0024] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or a specific number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0027] It is to be understood that when an element such as a layer, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. It will be understood that, although the terms "first", "second", etc. can be used herein to describe various elements, these elements should not be limited by these terms since such elements are commonly known by other terms.

[0028] Reference will now be made to Figure 1The application discloses a filter non-woven fabric 1, which comprises a surface layer 10, an intermediate layer 20 and a bottom layer 30 arranged in sequence; wherein the surface layer 10 is arranged as a fine filtration layer and is prepared by electrospinning nanofiber; the intermediate layer 20 is arranged as a main filtration layer and is prepared by high-efficiency stationary melt-blown polypropylene; and the bottom layer 30 is arranged as a support layer and is prepared by spun-bonded polyester. Specifically, the fiber diameter of the surface layer 10 is arranged as 80-200 nm, the area density is arranged as 0.3-0.8 g / m2, and the thickness is arranged as 5-15 μm, so as to form an ultra-fine limiting network, provide high initial efficiency and low surface deposition; the fiber diameter of the intermediate layer 20 is arranged as 1-3 μm, the area density is arranged as 15-30 g / m2, and the thickness is arranged as 0.3-0.6 mm, and the electret is treated by fluorination and corona electret, so as to ensure the high charge stability and high efficiency and low resistance of the intermediate layer 20; the fiber diameter of the bottom layer 30 is arranged as 15-25 μm, the area density is arranged as 20-40 g / m2, and the thickness is arranged as 0.15-0.3 mm, so as to ensure the high mechanical strength and airflow dispersing capacity of the bottom layer 30, and simultaneously provide protection for the intermediate layer 20, i.e. the main filtration layer. More specifically, the filter non-woven fabric 1 is produced by the following steps: raw material preparation, including preset amount of PP chip, PET chip and functional master batch; bottom layer 30 production, prepared spun-bonded PET meeting preset parameter standard, for online compounding; intermediate layer 20 production, prepared PP melt-blown layer containing preset amount of fluorine-containing electret master batch, and then nanofiber surface layer 10 is obtained on the surface of the intermediate layer 20 by online electrospinning; layering, the prepared intermediate layer 20 compounded with the surface layer 10 is compounded online to the bottom layer 30, and the non-woven fabric is obtained by hot air penetration bonding; the non-woven fabric is subjected to online synergistic electret treatment by corona and water mist polarization; the non-woven fabric is subjected to functional post-treatment, and additional functions are added to the non-woven fabric according to product requirements; the non-woven fabric is dried, slitted and wound, and then the non-woven fabric is subjected to ultrasonic edge reinforcement to obtain filter non-woven fabric 1 product. Based on the above, the filter non-woven fabric 1 of the application adopts one-step online compounding to directly deposit nanofiber on the melt-blown layer, and then hot-press compounding spun-bonded bottom layer 30, so as to reduce production steps and enhance interlayer bonding force, at the same time, only nanofiber is compounded on the filter material surface layer 10, which can greatly reduce the cost; adding fluorine-containing electret master batch in the PP melt-blown raw material can significantly improve the charge storage capacity and environmental stability, and the combination of corona discharge and water mist polarization in the production process can produce more uniform and stable bipolar charge layer; hot air penetration bonding is used to replace traditional hot rolling point bonding, which provides overall uniform bonding, small porosity loss, makes the non-woven fabric more fluffy and soft, and has higher dust holding capacity, and the ultrasonic edge reinforcement treatment reinforces the edge of the filter material, which can effectively prevent the non-woven fabric from delaminating in use.

[0029] Further, the nanofiber of the surface layer 10 adopts one of PET or PA6.

[0030] Furthermore, in one embodiment, the surface layer 10 also contains 0.5-2% functional additives. Specifically, the functional additives in the surface layer 10 are one or more mixtures of quaternary ammonium salt antibacterial agents, silver-based antibacterial agents, and fluorocarbon hydrophobic agents. Based on this, the surface layer 10 achieves its antibacterial and antiviral functions by adding quaternary ammonium salt antibacterial agents or silver-based antibacterial agents to the nanofibers; simultaneously, the addition of fluorocarbon hydrophobic agents to the surface layer 10 enhances its moisture-proof and oil-proof functions.

[0031] Furthermore, the fluorinated electret masterbatch in the intermediate layer 20 production process uses 5% PTFE nanoparticles.

[0032] Furthermore, in one embodiment, the intermediate layer 20 also contains 30% activated carbon powder. Based on this, the intermediate layer 20 achieves the adsorption function of odors and volatile organic compounds by adding activated carbon powder.

[0033] Furthermore, in one embodiment, the bottom layer 30 also contains 1-3% of a hydrophilic modifier. Based on this, the hydrophilic treatment of the bottom layer 30 can enhance liquid filtration and diffusion performance.

[0034] In some embodiments, the thickness of the surface layer 10 can be set to 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm or 15μm.

[0035] In some embodiments, the surface density of the 10-layer layer can be set to 0.3 g / m², 0.4 g / m², 0.5 g / m², 0.6 g / m², 0.7 g / m², or 0.8 g / m². In some embodiments, the thickness of the intermediate layer 20 may be set to 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm or 0.6 mm.

[0036] In some embodiments, the areal density of the intermediate layer 20 can be set to 15 g / m², 20 g / m², 25 g / m², or 30 g / m².

[0037] In some embodiments, the thickness of the bottom layer 30 can be set to 0.15mm, 0.2mm, 0.25mm or 0.3mm.

[0038] In some embodiments, the surface density of the bottom layer 30 can be set to 20g / m², 25g / m², 30g / m², 35g / m², or 40g / m².

[0039] Furthermore, in one embodiment, the filter nonwoven fabric 1 is specifically produced using the following steps: S1. Take a preset amount of PP and PET slices and dehydrate them in an 80℃ oven for 4 hours (moisture content ≤50ppm). S2, intermediate layer 20 raw material pretreatment: PP chips, 5% fluorine-containing electret masterbatch and 30% activated carbon powder are thoroughly mixed; S3, Surface Layer 10 Raw Material Pretreatment: PET is dissolved in hexafluoroisopropanol (concentration 12wt%), 0.8% quaternary ammonium salt antibacterial agent is added, and the mixture is thoroughly mixed. S4. Based on Reicofil4 spunbond yarn, under the process conditions of melt temperature of PET 290℃, spinning speed of 3500m / min, airflow stretching pressure of 0.25MPa, and web forming speed of 100m / min, a PET spunbond fabric with an areal density of 25g / m² and a thickness of 0.2mm is produced. S5. Online composite of meltblown / nanofiber: The intermediate layer 20 is meltblown under the conditions of double-row spinneret holes (0.3mm diameter) and air gap of 1.0mm; then, based on a multi-needle array (100 needles / m), electrospinning treatment is performed on the surface of the intermediate layer 20 20cm below the meltblown die. Before the meltblown fiber is completely solidified, the nanofiber is directly deposited on its surface to form physical entanglement, thereby realizing the online composite of meltblown / nanofiber and obtaining a composite structure of intermediate layer 20 and surface layer 10. S6. Based on the stacking sequence of bottom layer 30 (PET spunbond layer) → middle layer 20 (PP meltblown) / top layer 10 (nanofiber layer), the hot air penetration bonding of the three-layer structure is completed under the conditions of hot air temperature of 145℃, wind speed of 2.5m / s, penetration time of 8s and cooling roller temperature of 20℃ to obtain nonwoven fabric. S7. The nonwoven fabric is subjected to dual-segment synergistic electret treatment. Segment 1 is subjected to corona discharge treatment under the conditions of ±30kV voltage, 10mm electrode spacing and 10m / min fabric walking speed. Segment 2 is subjected to water mist polarization treatment under the conditions of deionized water + 0.1% isopropanol atomizing liquid, water pressure of 0.3MPa, droplet size of 5-10μm and polarization voltage of +15kV. S8. Perform functional post-treatment on the nonwoven fabric, including hydrophobic treatment: impregnate the bottom layer 30 with 5% fluorocarbon emulsion, with a roll-off rate of 80%; antibacterial treatment: spray the top layer 10 with 0.5% quaternary ammonium salt solution and microwave curing; hydrophilic treatment: impregnate the bottom layer 30 with 3% polyethylene glycol derivative. S9. Drying and laser cutting of non-woven fabric; S10. The edge of the nonwoven fabric is reinforced by an ultrasonic welding machine at a frequency of 20kHz, a pressure of 0.4MPa, and a welding width of 3mm to obtain the filter nonwoven fabric 1 finished product. S11. The finished product is wound up and sealed in an anti-static aluminum foil bag.

[0040] The embodiments of the present invention will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this invention, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art. Example

[0041] In this embodiment, based on the above-mentioned filter nonwoven fabric 1 formulation and preparation method, the surface density of the top 10 layer is limited to 0.6 g / m², the surface density of the middle 20 layer is limited to 25 g / m² and contains 30% activated carbon, and the surface density of the bottom 30 layer is limited to 30 g / m². That is, the total surface density of the filter nonwoven fabric 1 is limited to 55.6 g / m².

[0042] Furthermore, the total thickness of the filter nonwoven fabric 1 is limited to 0.52 mm.

[0043] Furthermore, in this embodiment, the functional additives include fluorinated electret masterbatch, activated carbon powder, and quaternary ammonium salt antibacterial agents.

[0044] Compare with Example 1 The single-layer electrostatic electret PP meltblown fabric has a total thickness of 0.45mm and a total areal density of 50.0g / m², and is produced by ordinary corona electret processing.

[0045] Compare with Example 2 Fiberglass composite fabric is made of fiberglass and cellulose composite, with a total thickness of 0.60mm and a total areal density of 80.0g / m².

[0046] The filter nonwoven fabric 1 prepared based on Example 1 and its preparation method was subjected to the following performance tests in conjunction with Comparative Example 1 and Comparative Example 2. The performance test indicators, test methods and test results are shown in Tables 1 to 4.

[0047] I. Filtration efficiency and resistance (ISO16890 / EN1822) Table 1

[0048] II. Dust Holding Capacity and Service Life (SAEJ726 / ISO12103-A2 Dust) Table 2

[0049] *Note: Simulated automotive air filter operating conditions (dust concentration 1g / m³, wind speed 2.5m / s) III. Environmental stability (ISO 5630 damp heat aging) Table 3

[0050] IV. Multifunctional Verification Table 4

[0051] In summary, the filter nonwoven fabric 1 of the present invention is based on the above-described embodiment 1: (1) Example 1 outperformed Control Example 1 in PM0.3 filtration efficiency by 1.78% (initial) and 0.88% (after dust containment); pressure drop was reduced to 67% of 3M, and overall quality factor (QF) was increased by 107%.

[0052] (2) The dust holding capacity of Example 1 is 68% higher than that of Control Example 1, and the theoretical replacement mileage is extended by 70%.

[0053] (3) Example 1 showed an efficiency decay of <0.1% under extreme humid and hot conditions, and its charge stability was nearly twice that of Control Example 1.

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A filter nonwoven fabric, characterized in that, include: The material consists of a top layer, a middle layer, and a bottom layer, arranged in sequence; the top layer is a fine filter layer, which is made by electrospinning nanofibers. The middle layer is set as the main filter layer and is made of high-efficiency electret meltblown polypropylene; the bottom layer is set as the support layer and is made of spunbond polyester. The surface layer has a density of 0.3-0.8 g / m² and a thickness of 5-15 μm to form an ultrafine limiting network; the middle layer has a density of 15-30 g / m² and a thickness of 0.3-0.6 mm, and the electret is treated with fluorination and corona electret; the bottom layer has a surface density of 20-40 g / m² and a thickness of 0.15-0.3 mm. The filter nonwoven fabric is produced using the following steps: raw material preparation, including a predetermined amount of PP chips, PET chips, and functional masterbatch; bottom layer production, producing spunbond PET that meets predetermined parameter standards for online lamination; intermediate layer production, producing a PP meltblown layer containing a predetermined amount of fluorinated electret masterbatch, followed by online electrospinning to obtain a nanofiber surface layer on the surface of the intermediate layer; lamination, online lamination of the prepared intermediate layer with the surface layer to the bottom layer, and hot air penetration bonding to obtain the nonwoven fabric; online synergistic electret treatment of the nonwoven fabric through corona and water mist polarization; functional post-treatment of the nonwoven fabric, adding additional functions to the nonwoven fabric according to product requirements; drying, slitting, and winding the nonwoven fabric, followed by ultrasonic edge reinforcement to obtain the finished filter nonwoven fabric.

2. The filter nonwoven fabric according to claim 1, characterized in that, The surface nanofibers are made of either PET or PA6.

3. The filter nonwoven fabric according to claim 1, characterized in that, The surface layer also contains 0.5-2% functional additives.

4. The filter nonwoven fabric according to claim 1, characterized in that, The fluorinated electret masterbatch in the intermediate layer production process uses 5% PTFE nanoparticles.

5. The filter nonwoven fabric according to claim 1, characterized in that, The surface layer thickness can be set to 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm or 15μm.

6. The filter nonwoven fabric according to claim 1, characterized in that, The surface density can be set to 0.3 g / m², 0.4 g / m², 0.5 g / m², 0.6 g / m², 0.7 g / m², or 0.8 g / m².

7. The filter nonwoven fabric according to claim 1, characterized in that, The thickness of the intermediate layer can be set to 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm or 0.6mm.

8. The filter nonwoven fabric according to claim 1, characterized in that, The density of the intermediate layer can be set to 15g / m², 20g / m², 25g / m² or 30g / m².

9. The filter nonwoven fabric according to claim 1, characterized in that, The thickness of the bottom layer can be set to 0.15mm, 0.2mm, 0.25mm or 0.3mm.

10. The filter nonwoven fabric according to claim 1, characterized in that, The bottom surface density can be set to 20g / m², 25g / m², 30g / m², 35g / m² or 40g / m².

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