Composite filter media and method

Abstract

A device may include a first distribution of nanofibers. A device may include a second distribution of fibers in contact with the first distribution of nanofibers, wherein the first distribution of nanofibers has a first diameter distribution with a peak value that is less than 150 nm; and wherein the second distribution of fibers have a second diameter distribution with a peak value that is larger than the first peak value wherein the composite filter media has a void volume of greater than 70%.

Description

COMPOSITE FILTER MEDIA AND METHODCross Reference to Related Applications

[0001] This patent application claims the benefit of priority, under 35 U.S.C. § 119(e), to U.S. Provisional Patent Application Serial No. 63 / 445,292, entitled “High Performance Filtration Media,” filed on Feb 13, 2023, which is hereby incorporated by reference herein in its entirety.

[0002] This patent application claims the benefit of priority, under 35 U.S.C. § 119(e), to U.S. Provisional Patent Application Serial No. 63 / 445,293, entitled “A Composite Filter Media and its Preparation Method,” filed on Feb 13, 2023, which is hereby incorporated by reference herein in its entirety.

[0003] This patent application claims the benefit of priority, under 35 U.S.C. § 119(e), to U.S. Provisional Patent Application Serial No. 63 / 445,294, entitled “Multi-Component Nanofiber Composite Structure Filter Media,” filed on Feb 13, 2023, which is hereby incorporated by reference herein in its entirety.Technical Field

[0004] The present disclosure relates generally to a composite filter media and its preparation method.Background

[0005] In today’s world, with the continuous advancement of industrialization and urbanization, a large amount of toxic and harmful substances is discharged into nature from industrial production and human life activities, it has far exceeded the self purification ability of nature, causing serious environmental problems. Among them, air pollution has a direct impact on human beings. It not only deteriorates the quality of air around us leading to high frequency of fog and hazy weather around the world, but also seriously threatens human life and health. For example, the fine pollutants in the air which once inhaled into the human body can directly enter the bronchi, alveoli and blood to cause asthma, bronchitis, cardiovascular disease, pneumoconiosis,lung cancer and other diseases. It can cause irreversible serious harm to human health. How to effectively reduce the impact of air pollution on human beings has become a major worldwide issue.

[0006] Humans have developed a variety of methods and technical measures for removing fine particles from the atmosphere. Among them, the scheme of physical filtration using fiber media was considered the most effective, reliable and economical way. Among many fiber composite filter media, nanofiber composite filter media has the advantages of large specific surface area and high separation efficiency. Further, when the fiber diameter reaches the nanometer scale, the air flow near the single fiber can slip over the fiber surface, so that the flow resistance of the composite filter media will be significantly reduced. Therefore, the nanofiber composite filter media shows an excellent application prospect in the field of air filtration. However, there were also some inherent shortcoming in the nanofiber composite filter media, such as the short distance between nanofibers, i.e. compact accumulation structure and the large fiber filling density, which make nanofiber composite filter media have higher flow resistance and lower dust holding capacity, especially at high efficiency region. It greatly restricts the application of nanofiber composite filter media in broader areas.

[0007] The patent number of CN10698420 IB discloses a composite air filter membrane with high efficiency, low flow resistance and high dust holding capacity. By setting a nano cobweb layer, beaded fiber layer and nano cobweb covering layer from bottom to top, the composite filter media formed a certain filtration gradient to improve the dust holding capacity. However, the process stability of electrospinning nanofiber layer with nano cobweb and bead structure was poor, and the adjustable efficiency of cobweb coverage and bead structure was still low. There were still many problems to be solved in its promotion and application.

[0008] The patent number of CN201480041084.1 disclosed a nanofiber composite filter media with high dust holding capacity. The ratio of the geometric mean diameter of the fiber at the upstream nanofiber composite filter media to the geometric mean diameter of the fiber at the downstream nanofiber composite filter media was 1.2 to 2.8. By this method, the nanofiber composite filter media formed a certain filtration gradient to achieve the goal of high dustholding capacity. However, the inner structure of the nanofiber composite filter media in this scheme was still compact, which can not effectively solve filling density issue of nanofiber, and the improvement of the filtration performance was limited.

[0009] An improved nanofiber composite technology that provides high- performance filter materials with improved efficiency and dust loading capacity while maintaining the low flow resistance is needed. The current inventive media and technology provides a material, a device and method that fulfills this desired need.Brief Description of the Drawings

[0010] FIG. 1 shows a cross-sectional structure of Example 1 of the composite filter media according to one example.

[0011] FIG. 2 shows a cross-sectional structure of Example 2 and Example 4 of composite filter media according to one example.

[0012] FIG. 3 shows a flow chart of a preparation method of composite filter media according to one example.

[0013] FIG. 4 shows a diameter distribution diagram of nanofiber composite filter media in Example 4 of a composite filter media according to one example.

[0014] FIG. 5 shows a graph shows the dust holding capacity diagram of the composite filter media in Example 4 and single-layer nano composite filter media according to one example.

[0015] FIG. 6 shows a cross-sectional structure of Example 5 of a composite filter media according to one example.

[0016] FIG. 7 shows a graph showing the dust holding capacity diagram of the composite filter media in Example 5 and single-layer nanofiber composite filter media according to one example.

[0017] FIG. 8 shows a cross-sectional structure of Example 6 of a composite filter media according to one example.

[0018] FIG. 9 shows a graph showing the dust holding capacity diagram of a composite filter media in Example 6, PTFE membrane composite filter media of a Japanese company and superfine glass fiber composite filter media of an American company according to one example.

[0019] FIG. 10 shows an image of fibers using a scanning electron microscope according to one example.

[0020] FIG. 11 shows a cross-sectional structure of a nanofiber layer between two supporting layers according to one example.

[0021] FIG. 12 shows an image of fibers using a scanning electron microscope according to one example.

[0022] FIG. 13 shows an image of fibers using a scanning electron microscope according to one example.

[0023] FIG. 14 shows a graph showing a fiber diameter distribution according to one example.

[0024] FIG. 15 shows an image of fibers using a scanning electron microscope according to one example.

[0025] FIG. 16 shows a graph showing the curve of the change of the pressure drop of the composite filter media with the NaCl loading according to one example.

[0026] FIG. 17 shows a cross-sectional structure of a composite filter media having multiple nanofiber layers (11A, 12A, 13A) and inner support layers 21 A / 22A and outer support layers 31 A / 32A according to one example.

[0027] FIG. 18 shows a graph of the change curves of pressure drop of the three composite filter medias with the loading time according to one example.

[0028] FIG. 19 shows a cross-sectional view of an air composite filter media structure with a nanofiber layer attached to the bottom of a support layer according to one example.

[0029] FIG. 20 shows a cross-sectional view of an air composite filter media structure with a nanofiber layer attached to the top of a support layer according to one example.

[0030] FIG. 21 shows a cross-sectional view of an air composite filter media structure with a nanofiber layer attached to the top of a nanofiber support layer according to one example.

[0031] FIG. 22 shows a cross-sectional view of an air composite filter media structure with a nanofiber layer attached to the bottom of a nanofiber support layer on the top of the structure according to one example.

[0032] FIG. 23 shows a cross-sectional view of an air composite filter media structure with a nanofiber layer attached to the top of a nanofiber support layer on the top of the structure according to one example.

[0033] FIG. 24 shows a cross-sectional view of an air composite filter media structure with multiple nanofiber layers attached to various layers of the structure according to one example.

[0034] FIG. 25 shows a pleated panel filtration element including composite fiber media according to one example.

[0035] FIG. 26 shows a multi-V style filtration element including composite fiber media according to one example.

[0036] FIG. 27 shows a cylindrical filtration element including composite fiber media according to one example.Description of Embodiments

[0037] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

[0038] Among other things, the present invention is to solve the problems of compact structure of nanofiber composite filter media, including excessive fiber filling density, high flow resistance and low dust holding capacity. It provided a composite filter media and its preparation method, which used the inner support layer as a skeleton to maintain the void volume of nanofiber composite filter media, promoted the formation of more open structures between nanofibers, and achieved the goal of high filtration efficiency and low flow resistance and high dust holding capacity.

[0039] The present invention can effectively prepare a nanofiber composite filter media with an open structure, realize the transformation of the surface filtration mechanism of the existing nanofiber composite filter media to the depth filtration mechanism, and significantly improved the dust holding capacity and quality factor of the composite filter media ( QF=-ln(l- Efficiency ) / dP); It changed the inherent defect of compact accumulationstructure of nanofiber, reduced the interference of compact structure of nanofibrous composite filter media on slip flow effect of air near single nanofiber, significantly reduced the drag force of composite filter media on air flow, and effectively realize the high efficiency and low flow resistance of the nanofiber composite filter media.Regarding Figures 1-9:

[0040] 1. Nanofiber Layer; 11. The First Nanofiber Layer; 12. TheSecond Nanofiber Layer; 13. The Third Nanofiber Layer; 14. The Fourth Nanofiber Layer; 15. The Fifth Nanofiber Layer; 16. The Sixth Nanofiber Layer;

[0041] 2 Inner Support Layer; 21. The First Inner Support Layer; 22.The Second Inner Support Layer; 23. The Third Inner Support Layer; 24. The Fourth Inner Support Layer; 25. The Fifth Inner Support Layer; 26. The Sixth Inner Support Layer;

[0042] 3. Outer Support Layer; 31. The First Outer Support Layer; 32.The Second Outer Support Layer.

[0043] The present invention provides a composite filter media, comprising a nanofiber layer, an inner support layer disposed on the lower side of the nanofiber layer and / or upper side, the inner support layer is used to support the nanofiber layer and reduce the filling density of the nanofiber;

[0044] The nanofiber layer includes nanofibers with a diameter of Inm to 5000nm, and the fiber diameter of the inner support layer does not exceed 100pm.

[0045] A composite filter media described in the present invention, as a preferred manner, the number of nanofiber layers is at least two, and the inner support layer is disposed between two nanofiber layers;

[0046] The inner support layer is any of the following or the combination of spunbond non-woven fabric, drylaid non-woven fabric, wet non-woven fabric, meltblown or fiber net with a grammage of less than 80g / m2.

[0047] A composite filter media described in the present invention, as a preferred method, the particle filtration efficiency of the downstream nanofiber layer is preferably greater than or equal to the particle filtration efficiency of the adjacent upstream nanofiber layer.

[0048] A composite filter media described in the present invention, as a preferred method, the particulate filtration efficiency of the downstream nanofiber layer and the adjacent upstream nanofiber layer particulate filtration efficiency difference is less than 60%.

[0049] A composite filter media described in the present invention, as a preferred method, the nanofiber layer further comprises nanofibers (l-100nm) and submicron fibers (0.1-lum) and optionally micron (>lum) fibers with a fiber diameter of less than or equal to 50pm; The fiber diameter of the nanofiber layer is a peak distribution and the peak is within the diameter range of the nanometer or submicron meter, or the fiber diameter of the nanofiber layer is double peak or multi peak distribution and the first peak is within the diameter range of the nanometer and submicron size, and the other peaks are within the diameter range of the submicron and / or micron meter.

[0050] A composite filter media described in the present invention, as a preferred method, further comprises an outer support layer positioned above the uppermost nanofiber layer and / or below the lowest nanofiber layer and / or in the middle, the support layer is used to provide strength and stiffness for the composite filter media, the outer support layer connected below the lowest nanofiber layer is the first outer support layer, and the outer support layer connected above the uppermost nanofiber layer is the second outer support (can also function as a protection and / or efficiency and / or dust loading) layer;

[0051] The material of the nanofiber is polymer or inorganic, and the nanofiber can be any of the following: PA6, PA56, PA66, PAI 010, PAN, PLA, PU, CA, PVDF, PI, PMIA, PTFE, A12O3, SiO2 and ZrO2. The nanofiber can be continuous filaments and / or discontinuous fibers.

[0052] The material of the inner support layer (2 in Figure 1) is any one or the combination of the following: PP, PET, PE, PA, PVDF, CA, PAN, PET / PE, PET / LMPET, PLA, and glass fiber. When the inner support layer is (2) bicomponent, the weight ratio of polymer in the skin layer and core layer is between 30 / 70 and 70 / 30. The inner support layer has a mono-disperse fiber diameter distribution, or a poly-disperse fiber diameter distribution with multipeak value between 0.3 p m~ 100 p m.

[0053] The first outer support layer (3 in Figure 2) was spunbond nonwoven fabric, air laid nonwoven fabric, dry laid nonwoven fabric, wet laidnonwoven fabric, meltblown or fiber net with fiber size between 0.3 p m~ 100 pm.

[0054] The composite filter media of the present invention, as a preferred method, the micron and submicron fibers are staple fibers or continuous filaments. The material of the micron and submicron fiber is polymer or inorganic, and the micron fiber is any one or any combination of the following: PA6, PA56, PA66, PA1010, PAN, PLA, PU, PVDF, PS, CA, PI, PMIA, PTFE, PP, PET, PE, PA, PET / PE, PET / LMPET and glass fiber. In the nanofiber layer, if it is a multi-comoponent structure, the number ratio of nanometer fibers to micron fibers and / or submicron fibers is 1 :6 to 600: 1, and the mass ratio is 0.1 :99 to 10:1.

[0055] The composite filter media are prepared by a method comprising:

[0056] SI. A nanofiber layer is deposited on the inner support layer and a nanofiber layer is deposited on the first outer support layer by electrospinning. The nanofiber layer included nanofibers with a diameter of Inm to 5000nm, and the inner support layer was spunbonded nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown or fiber mesh with a fiber diameter of less than 100pm.

[0057] S2. The optional second outer support (can also function as a protection and / or efficiency and / or dust loading) layer is placed above the nanofiber layer (1, Figure 1) on the uppermost side. The nanofiber layer, the inner support layer and the outer support layer are compounded by hot pressing, glue bonding, or ultrasonic compounding to obtain a composite filter medias.

[0058] The present invention related to a preparation method of composite filter media. As a preferred method, in step SI, the number of inner support layers is at least one, and the thickness and basis weight of the inner support layers can be the same or different;

[0059] The first outer support layer (31, Figure 2) and the optional second outer support layer (32, Figure 2) (can also function as a protection layer, an efficiency layer or a dust loading layer) were spunbond nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven or fiber mesh prepared by other method.

[0060] The preparation method of the composite filter media according to the present invention, as a preferred method, in step SI, the nanofiber layer (1,Figure 1) is obtained by depositing nanofibers alone, or depositing nanofibers, micro fibers and / or submicron fibers simultaneously on the inner support layer (2, Figure 1) through electrospinning or the combination of electrospinning and other fiber dispersion methods, and the fiber diameter of the micro fibers generated by electrospinning method is likely less than or equal to 5pm. The fiber diameter of the micro fibers generated by other fiber spinning and dispersion method is likely less than or equal to 60pm. The number ratio of the nanofibers to the micro fibers and / or the submicron fibers was 1 :6 to 600: 1, and the mass ratio of nanometer size fiber to micron size fiber is between 0.1 :99 to 10: 1.

[0061] The present disclosure provides a nanofiber composite filter media with high efficiency, low flow resistance and high dust holding capacity, which is particularly suitable for filtering and separating particles in the air and liquid.

[0062] In a set of embodiments of the present disclosure, The low flow resistance and high efficiency nanofiber composite filter media consists of two or more layers of nanofiber and one or more layers of inner support layers. The inner support layer is arranged in the middle of adjacent nanofiber layers. The nanofiber layers have the same or different particle filtration efficiency and flow resistance to flow. The inner support layer is any one or several of low basis weight spunbonded nonwoven fabric, dry laid nonwoven fabric, air laid nonwoven fabric, wet laid nonwoven fabric, meltblown or other woven or nonwoven materials, the fiber diameter of the inner support layer does not exceed 100 pm, the thickness of the inner support is preferably no more than 0.5mm.

[0063] In another embodiment of the present disclosure, the low flow resistance and high efficiency nanofiber composite filter media consists of two or more layers of nanofiber and one or more layers of inner support layers. The inner support layer is arranged in the middle of adjacent nanofiber layers; In terms of the arrangement of filter materials, the nanofiber layer has preferably a gradient increasing particle filtration efficiency from the upstream side to the downstream side. The inner support layer is a uniformly distributed short fiber or filament, and the short fiber or filament is made of any one or any combination of PP, PET, PE, PA, PVDF, PAN, CA, PET / PE, PET / LMPET, and glass fibers.

[0064] In another embodiment of the present disclosure, the low flow resistance and high efficiency nanofiber composite filter media consists of two or more layers of nanofiber and one or more layers of inner support layers. The inner support layer is arranged in the middle of adjacent nanofiber layers; The nanofiber layer is composed of nanofibers or the combination of nanofibers, submicron and micron fibers. The nanofiber layer has a minimum fiber diameter as low as 5nm and a maximum fiber diameter as high as 50pm fiber diameter;

[0065] In some embodiments of the present disclosure, the statistical peak value of the fiber diameter distribution of the nanofiber layer is between 10 nm and 120 nm. In other embodiments, the fiber diameter distribution of the nanofiber layer has a double or multiple peak distribution, wherein the first peak is located between 20 nm and 120 nm, and the other peaks are located at any interval between 200 nm and 4000 nm or between 4pm and 50pm.

[0066] In another embodiment of the present disclosure, the low flow resistance and high efficiency nanofiber composite filter media consists of two or more layers of nanofiber and one or more layers of inner support layers. The inner support layer is arranged in the middle of adjacent nanofiber layers;

[0067] The inner support layer is a micron or submicron fiber layer with a fiber diameter between 0.3pm and 100 pm prepared by electrospinning method or other fiber spinning method or other fiber dispersion and web forming methods. In some embodiments, the micron or submicron fiber layer has a monodisperse fiber diameter distribution. In other embodiments, the fiber diameter distribution of the micron or submicron fiber layer shows a poly dispersity, and the peak value of the polydisperse fiber diameter distribution is located in any range of 0.3 p m to lOOp m.

[0068] As used herein, unless otherwise indicated, the "high efficiency and low flow resistance" for the composite filter media in the present disclosure refers to that the composite filter media shows filtration efficiency of at least 60% and flow resistance of no more than 500Pa when tested according to ISO29463-3 or other equivalent standards. The term "Almost the same" refers to that different composite filter media show filtration efficiency and flow resistance differences of less than 6% when tested according to ISO29463-3 or other equivalent standards.

[0069] The term "nanofiber" refers to a fiber with a fiber diameter of Inm to 5000nm. The nanofiber can be made of polymer, such as PA, PVDF, PLA, PES, PEI, CA, PS, PAN, PI, PMIA, etc., or inorganic materials, such as AI2O3, SiCh, ZrCh, etc. Generally, nanofibers are made by electrospinning. Generally, when the material is a polymer, a spinnable solution of the polymer is prepared and then electrospinning. When the material is inorganic, the spinnable solution or solution precursor is prepared by electrospinning and then calcining. The nanofibers can be continuous filaments or staple fibers.

[0070] The term "nanometer fiber" refers to the fiber with a diameter of 5nm to lOOnm, "submicron fiber" refers to the fiber with a diameter of 0.1pm to 1 m, "micron fiber" refers to the fiber with a diameter larger than 1pm, the nanometer size fiber and submicron size fiber and micron size fiber can be continuous filament or staple fiber; The fiber can be straight or curly; It can be monocomponent or multicomponent. In some embodiments, the material of the nanometer size fiber and submicron and micron size fiber is polymer, such as PP, PET, etc. In other embodiments, the material of the nanometer size fiber and submicron and micron size fiber is inorganic, such as superfine glass fiber.

[0071] The terms "monocomponent" and " bicomponent refer to polymer materials that make up the fiber. Monocomponent refers to the polymer with only one component in the fiber, such as PET, PE, etc. Bicomponents refer to two kinds of polymers constituting the fiber. In this application, Bicomponent fiber refers to the fiber with a skin layer and a core layer structure, wherein the skin layer polymer surrounds the core layer polymer and extends continuously in the fiber length direction. The skin layer of bicomponent fiber generally adopts polymers with low melting point, such as PE and LMPET, and the core layer generally adopts polymers with higher melting point, such as PET. For bicomponent fibers, the polymer of the skin and core layers can be in the weight ratio of 40 / 60, 35 / 65, 50 / 50 or any other ratio with better implementation effect.

[0072] The term "polymer", also known as macromolecular compound, refers to compounds with a relative molecular mass of thousands or even millions, macromolecular compound include homopolymers, copolymers, blends of homopolymers and copolymers in any weight ratio, and modified polymers prepares by physical and chemical modification methods. Unless otherwiseindicated, the term "polymer" includes all spatial configurations of macromolecular compound, such as isotactic, syndiotactic and atactic.

[0073] The term "upstream" refers to the flow inlet side and "downstream" refers to the flow outlet side.

[0074] The present invention includes the following advantages:

[0075] The present invention describes the scheme of creating high performance nanofiber media by dividing a nanofiber layer into a plurality of nanofiber layers, and an inner support layer is arranged on the upper side or the lower side of each nanofiber layer; Even if the nanofiber has a narrow fiber diameter distribution, the scheme of the application can still effectively prepare high performance nanofiber media, realize the transformation from surface filtering mechanism to depth filtering mechanism of nanofiber composite filter media, and significantly improve the dust holding capacity of composite filter media;

[0076] The technical scheme of the filter material provided by the application changes the congenital defect of the dense structure of nanofibers, reduces the interference of the dense structure of the nanofiber filter material on the slip flow effect of air near the single fiber, significantly reduces the drag force of the composite filter media on the air flow, and effectively realizes the high efficiency and low flow resistance of the composite filter media.

[0077] The present invention provides a composite filter media of multicomponent nanofiber composite structure, the composite filter media includes a support layer and a multi-component nanofiber layer, which can be a structure composed of a support layer and a single nanofiber layer, or a composite structure of an outer support layer, an inner support layer and a multi-layer nanofiber layer.

[0078] The lofty structure nanofibers often have relatively large diameters. Generally, the fiber diameter is 100 nm to 5pm, preferably more than 0.1pm (lOOnm), preferably more than 0.3 pm, preferably more than 0.5pm, and the loftiness (void volume) is more than 70%; The ultra-fine nanofiber has a relatively fine diameter; the fiber diameter is 10 nm to 300 nm, preferably less than 0.3 pm, preferably less than 0.15 pm; The diameter of lofty nanofibers is larger than that of ultrafine nanofibers. The mass mixing ratio of the fine to coarse fibers can range from 0.1 :99 to 80:20. By adjusting the processparameters, the filtration efficiency of multi-component nanofiber layer can be 30%~99.9999%; The prepared nanofibers with different filtration efficiency can be compounded by hot pressing, glue bonding or ultrasonic compounding to meet specific use needs.

[0079] The lofty structure nanofibers and the ultra-fine nanofiber can be prepared by multi needle electrospinning or needleless electrospinning technology. The two or more kinds of fibers are mixed together in the spinning process, and the concentration of two or more electrospinning solutions is likely different and the polymer used for electrospinning can be the same or different.

[0080] The optional polymer of lofty structure nanofibers and ultra-fine nanofibers can be one or several combinations of the following examples, the selection of polymers includes but is not limited to : Polyurethane, Polystyrene, Polyimide, Polyethylene glycol terephthalate, Polybutylene terephthalate, Nylon (Nylon-6, Nylon-66, Nylon-56, Nylon-1010) , Polyacrylonitrile, Polyvinylidene difluoride, Poly- Vinyl Fluoride, Polytetrafluoroethylene, Chlorotrifluoroethylene, Polyethylene oxide, Polymethyl methacrylate, Poly (m-phenyleneisophthalamide) , Polysulfone, Polyphenylene sulfone resins, Poly ethersulfone, Polyphenylene sulfide, Polyetherimide, Polylactic acid, Poly-l-lactide, Poly-d-lactide, Polycaprolactone, Polyvinyl alcohol, polyvinyl pyrrolidone, Acrylic resin, Cellulose acetate, Chitosan, Silk fibroin and copolymers or homopolymers of the above polymers, etc. The choice of solvent includes, but is not limited to: Water, Ethanol, benzyl alcohol, Formic acid, Acetic Acid, Acetone, N,N- Dimethylformamide, N,N-dimethylacetamide, Dimethyl sulfoxide, N- Methylpyrrolidone, Dichloromethane, Trichloromethane, Hexafluoroisopropanol, Tetrahydrofuran, Trifluoroacetic acid, Tetrafluoroethene, etc.

[0081] The present invention provides a composite filter media with multi-component nanofiber composite structure, and its preparation method includes the following steps:

[0082] Add one or two kinds of polymers into the same or different solvents respectively; evenly stir until fully dissolved to obtain twoelectrospinning solutions with likely different mass percentage concentration and viscosity, and the solubility range is likely between lwt% to 70wt%.

[0083] The technical solution provided by the present application can achieve the following beneficial effects:

[0084] ( 1 ) Even if the nanofiber has a narrow fiber diameter distribution, the scheme of the present application can still effectively prepare lofty structure composite filter media, realize the transformation of the surface filtering mechanism of the nanofiber composite filter media to the depth filtering mechanism, and significantly improve the dust holding capacity.

[0085] (2) The technical scheme of the composite filter media provided by the present application overcome the defects of compact accumulation structure, improves the bulkiness and porosity of nanofiber composite filter media, reduces the flow resistance and improves the dust holding capacity.

[0086] Among other things, the present invention provides a composite filter media of multi-component nanofiber composite structure, the composite filter media includes a support layer and a multi-component nanofiber layer, which can be a structure composed of a support layer and a single nanofiber layer, or a composite structure of an outer support layer, an inner support layer / layers and a multi-layer nanofiber layer / layers; one or more inner support / separation layer / s and one or more nanofiber layers.

[0087] The lofty structure nanofibers often have relatively large diameters. Generally, the fiber diameter is 100 nm to 5pm, preferably more than 0.1pm (lOOnm), preferably more than 0.3 pm, preferably more than 0.5pm, and the loftiness(void volume) is more than 70%; The fine nanofiber has a relatively fine diameter; the fiber diameter is 10 nm to 300 nm, preferably less than 0.3 pm, preferably less than 0.15 pm; The diameter of lofty nanofibers is larger than that of fine nanofibers. The mass mixing ratio of the large and fine fibers can range from 10:90 to 99:0.1. By adjusting the process parameters, the filtration efficiency of multi-component nanofiber layer can be 30%~99.99995%; The prepared nanofibers with different filtration efficiency can be compounded by hot pressing, glue bonding or ultrasonic compounding to meet specific use needs.

[0088] The lofty structure nanofibers and the fine nanofiber can be prepared by multi needle electrospinning or needleless electrospinning technology. The two or more kinds of fibers are mixed together in the spinning process, and the concentration of two or more electrospinning solutions is likely different, and the polymer used for electrospinning can be the same or different.

[0089] The optional polymer of lofty structure nanofibers and fine nanofibers can be one or several combinations of the following examples, the selection of polymers includes but is not limited to: Polyurethane, Polystyrene, Polyimide, Polyethylene glycol terephthalate, Polybutylene terephthalate, Nylon(Nylon-6, Nylon-66, Nylon-56, Nylon-1010, Polyacrylonitrile, Polyvinylidene difluoride, Poly- Vinyl Fluoride, Polytetrafluoroethylene, Chlorotrifluoroethylene, Polyethylene oxide, Polymethyl methacrylate, Poly (m- phenyleneisophthalamide) , Polysulfone, Polyphenylene sulfone resins, Polyethersulfone, Polyphenylene sulfide, Polyetherimide, Polylactic acid, Poly-1- lactide, Poly-d-lactide, Polycaprolactone, Polyvinyl alcohol, polyvinyl pyrrolidone, Acrylic resin, Cellulose acetate, Chitosan, Silk fibroin and copolymers or homopolymers of the above polymers, etc. The choice of solvent includes, but is not limited to: Water, Ethanol, benzyl alcohol, Formic acid, Acetic Acid, Acetone, N,N-Dimethylformamide, N,N-dimethylacetamide, Dimethyl sulfoxide, N-Methylpyrrolidone, Dichloromethane, Trichloromethane, Hexafluoroisopropanol, Tetrahydrofuran, Trifluoroacetic acid, Tetrafluoroethene, etc.

[0090] The present invention provides a composite filter media with multi-component nanofiber composite structure, and its preparation method includes the following steps : Add one or two or more kinds of polymers into the same or different solvents respectively, Evenly stir until fully dissolve to obtain two or more electrospinning solutions with same or different mass percentage concentration and viscosity, and the mass concentration range is between lwt% to 70wt%.

[0091] The technical solution provided by the present application can achieve the following beneficial effects:

[0092] ( 1 ) Even if the nanofiber has a narrow fiber diameter distribution, the scheme of the present application can still effectively prepare lofty structure composite filter media, realize the transformation of the surfacefiltering mechanism of the nanofiber filter media to the depth filtering mechanism, and significantly improve the dust holding capacity.

[0093] (2) The technical scheme of the composite filter media provided by the present application overcome the defects of compact accumulation structure, improves the loftiness (void volume) and porosity of nanofiber composite filter media, reduces the resistance and improves the dust holding capacity.

[0094] As used herein, unless otherwise indicated, the "high efficiency and low flow resistance" for the composite filter media in the present disclosure refers to that the composite filter media shows filtration efficiency of at least 60% and flow resistance of no more than 500Pa when tested according to ISO29463-3 or other equivalent standards. The term "Almost the same" refers to that different composite filter media show filtration efficiency and flow resistance differences of less than 6 % when tested according to ISO29463-3 or other equivalent standards. The terms “inner support layer”, “spacer layer”, “separation layer” refer to the same thing.

[0095] As used herein, unless otherwise indicated, the term "nanofiber" refers to a fiber with a fiber diameter of Inm to 5000nm. The nanofiber can be made of polymer, such as PA, PVDF, PLA, PES, PEI, CA, PS, PAN, PI, PMIA, etc., or inorganic materials, such as AI2O3, SiCE, ZrCh, etc. Generally, nanofibers are made by electrospinning. When the material is a polymer, it is necessary to prepare a spinnable solution of the polymer and then electrospinning. When the material is inorganic, the spinnable sol or solution precursor is prepared by electrospinning and calcining. The nanofibers can be continuous filaments or staple fibers.

[0096] As used herein, unless otherwise indicated, the terms "monocomponent" and “bicomponent” refer to polymer materials that can make up the fiber. Monocomponent refers to the polymer with only one component in the fiber, such as PET, PE, etc. Bicomponents refer to two kinds of polymers constituting the fiber. In the present application, multicomponent nanofibers refer to nanofibers with different structure and diameters in the nanofiber layer, that is, the mixture of lofty structure nanofibers and fine nanofibers.

[0097] As used herein, unless otherwise indicated, The term "polymer", also known as macromolecular compound, refers to compounds with a relativemolecular mass of thousands or even millions. Macromolecular compounds include homopolymers, copolymers, blends of homopolymers and copolymers in any weight ratio, and modified polymers prepared by physical and chemical modification methods. Unless otherwise indicated, the term "polymer" includes all spatial configurations of macromolecular compound, such as isotactic, syndiotactic and atactic.

[0098] As used herein, unless otherwise indicated, the term "loftiness" or “lofty” corresponds to void volume ( also known as porosity), and refers to the volume which is not occupied by a solid mass in a porous materials. The calculation formula is : void volume = 1Porosity = loftiness =void volume.

[0099] As used herein, unless otherwise indicated, the term "number” ratio of fibers refers to the number of fibers seen in a Scanning Electron Microscopy picture.

[0100] In automotive cabin air filtration and other air filtration to remove particulate and gaseous contaminants, it is desirable that the composite filter media has high filtration efficiency, low flow resistance, high dust loading capacity, low thickness, and good stiffness in order to achieve better filter construction and performance.

[0101] However, the current technology has significant limitations. For example, in order to haven a media with:

[0102] 1. low flow resistance (e.g. within 30Pa at 30cm / s),

[0103] 2. low thickness (e.g. within 1mm), and

[0104] 3. high dust loading capacity (e.g. 30g / m2with ASHRAE dust w / o cotton lint at 30cm / s and terminal dP of 150Pa), then the efficiency of the media using current technology would be low, ranging from 25% to 38% at 16.7cm / s flow rate.

[0105] In such instances, because the filtration efficiency is low, the particulate matter cannot be removed well, and the filtration performance of the media is poor.

[0106] Additionally, a large number of particulate pollutants reach the activated carbon layer, which may reduce the effective area of activated carbon and reduce its gas adsorption efficiency and capacity.

[0107] Similarly, in many prior art practices, if the filtration efficiency needs to be increased without increasing the thickness and basis weight of the composite filter media, the resistance will be increased significantly and the dust loading capacity will be reduced. For example, if the efficiency is increased to more than 50%, the resistance will exceed 40Pa at 30cm / s flow rate, and the dust loading capacity will be reduced to about 10g / m2with ASHRAE dust w / o cotton lint at 30cm / s and the terminal dP of 150Pa.

[0108] The prior art practices also run into the problem of desiring a high air permeability of the substrate contributing to carbon leakage of activated carbon. In order to reduce the resistance of the filter material, the substrate may then utilize high air permeability and low resistance, but if the substrate has high air permeability, carbon particles could leak through the substrate and fall off the composite filter media. In order to avoid this leakage problem, the prior art methods often chose a substrate with low air permeability or used large particle carbon. Yet, the substrate with low air permeability generally has greater resistance. The large particle carbon often increases the thickness of the filter material and often reduces adsorption efficiency compared to fine particle carbon. Both of the above schemes can have a negative impact on the overall performance of the composite filter media.

[0109] Among other things, the inventive composite media can comprise 1) a support layer, 2) an electrospun nanofiber layer thereon the support layer, 3) an adsorbing material layer on the nanofiber layer, and 4) a top layer disposed on the adsorbing material layer. The top layer can be meltblown material, triboelectric media, dry laid media, wet laid media, spunbond or these media with nanofiber coating on top or bottom, and / or any combination thereof.

[0110] In at least one embodiment, the adsorbing material can be selected from the group comprising activated carbon, activated carbon with glue powder, and other adsorbing materials.

[0111] In at least one embodiment, the top layer can have significant filtration efficiency. In at least one embodiment, the top layer can have significant dust loading capacity.

[0112] In at least one embodiment, adjacent layers can be bonded together by a bond selected from the group comprising ultrasonic bonds, hot melt glue spray bonds, glue powder with heat lamination bonds, membranetransferred glue lamination bonds, and / or any combination thereof. In at least one embodiment, the nanofibers can be selected from the group of materials comprising PVDF, nylon, CA, PS, PAN, PI, PMIA, TPU, PEI, PLA, PES and / or any combination thereof.

[0113] In at least one embodiment, the substrate can be a thermoplastic polymer. In at least one embodiment, each of at least two layers can be antimicrobial.

[0114] In at least one embodiment, the nanofibers can be selected from the group consisting of needle spinning electrospun nanofibers, needleless spinning electrospun nanofibers, centrifugal force spinning nanofiber, electroblowing nanofibers and / or any combination thereof.

[0115] In at least one embodiment, at least part of the media can have a high concentration (5-50% ) of active ingredients such as VC (vitamin C) through electrostatic spraying and electrospinning or coating method.

[0116] In at least one embodiment, the nanofibers have a diameter less than 1pm. In at least one embodiment, the nanofibers have a diameter less than ,3 m. In at least one embodiment, the nanofibers have a diameter less than , 15pm.

[0117] The instant invention provides an improved nanofiber composite technology that provides high-performance filter materials with improved efficiency and dust loading capacity while maintaining the low resistance and small thickness.

[0118] The instant invention also provides improved nanofiber composite technology that provides high-performance filter materials with reduced resistance and increased dust loading capacity while maintaining the same efficiency and thickness of other filter materials. And, while reducing the resistance and improving the efficiency, the same dust loading capacity and thickness can be maintained. And, while maintaining the same thickness, the above three indicators: efficiency, resistance and dust loading are improved at the same time, so as to greatly improve the overall filtration performance of the filter material, while the thickness and stiffness of the filter material can be well controlled and guaranteed.

[0119] In some embodiments the inventive nanofiber composite filter material includes antimicrobial properties and / or active ingredients such as VitaminC (VC) with release ability. Often in the prior art, any antibacterial and antiviral function present in the filter material is located in the substrate layer. This often limits the overall antibacterial and antiviral performance of the filter material because bacteria and virus particles are usually captured in the efficiency layer rather than in the substrate layer. The instant invention can add antibacterial and antiviral functions to all layers including the substrate layer. In some embodiments, the antimicrobial functions are located in the melt blown layer and / or nanofiber layer.

[0120] In some embodiments, electrostatic spraying and electrospinning method can be used to add high concentration active ingredients such as VC to the filter material. The moisture in the air can bring out VC, which can be beneficial to health and can moisturize the air for more comfort at the same time.In some embodiments of the invention, an air composite filter media structure IB has a nanofiber layer 10B attached to the supporting layer 20B. As shown an activated carbon layer 30B is disposed above the supporting layer with a larger pore fibrous material layer 40B disposed above the carbon layer 30B. A protective layer 50B can be disposed on top of the larger pore fibrous material layer. It should be noted that all the Figures are illustrative and the position of the layers can vary from that shown; for instance, the larger pore fibrous material layer 40B could be disposed between the support layer 20B is applied to the bottom of supporting layer 20B. The supporting layer 20B can add rigidity and / or structure to the composite filter media IB. The nanofiber layer 10B applied to a bottom of the support layer 20B as in Figure 25 may improve the overall media efficiency and also overcome carbon particle leakage problems and capture fine particles released from the active carbon during media process and filter usage. This nanofiber coating 10B can be applied to the top of the support layer 20B and / or the bottom of the support layer 20B. In FIG. 19, the nanofiber layer 10B is shown attached to the top of the support layer 20B.

[0121] In Fig. 20 the nanofiber layer / coating is disposed between the activated carbon layer (also sometimes called the adsorption layer) 30B and the larger pore fibrous material layer 40B comprising one or more of meltblown / electrostatic cotton / Spunbond / Wet-lay. Note that here a nano support layer 25B is also included. The nano support layer 25B can provide support for the nanofiber layer 10B when the nanofiber layer is not being applied to the supportlayer 20B. The carbon layer 30B and / or larger pore fibrous material layer 40B may not provide suitable structure for the nanofiber layer 10B so the additional nano support layer can be used.

[0122] In FIG. 21, the nanofiber layer 10B is disposed at the top portion of the media 3B. Here the nanofiber layer is attached to the bottom of the nano support layer 25B. However, the nanofiber layer 10B can also be attached to the top of the nano support layer 25B as shown in FIG. 20.

[0123] Various nanofiber layers 10B can be used in the media 4B as shown in FIG. 22 where 4 different nanofiber layers 10B1, 10B2, and 10B3 are illustrated. The nanofiber layers 10B 1-3 generally need support so a nanosupport layer 25B can be attached to the nanofiber layer 10B. The support layer 20B and each nano support layer 25B can have a nanofiber layer on both sides. At shown in Fig. 23 a nanofiber layer 10B was on both the top and the bottom of the media 5B.

[0124] In Fig. 23, the nanofiber layer 10B1 is disposed on the top of the media 6B but not on the bottom. FIGS. 20-24 do not include a protective layer of meltblown 50B as in these instances the larger pore fibrous material layer 40B is protected by the nano layers 10B / 25B.

[0125] There are multiple configurations of where the nanofiber 10B may be applied and located in a media structure such as media structures 1B-6B. Not all are shown in the Figures, but this invention recognizes and claims 1) a nanofiber layer 10B on an inside or an outside layer of a media, 2) multiple nanofiber layers 10B on the inside and / or on the outside of the media, 3) multiple nanofiber layers 10B wherein at least one nanofiber layer is on the outside of the media 1 and at least one is on the inside of the media.

[0126] In some embodiments, the nanofiber is applied to the top of the bottom layer and applied to the top of the top layer of the media. In some embodiments, the nanofiber is applied to the bottom of the bottom layer and applied to the bottom of the top layer of the media.

[0127] This invention can enable a media with high efficiency, low pressure drop, long life, and other functionalities and safety as described above. In automotive cabin air filtration and other air filtration, it can be desirable that the core composite filter media has high filtration efficiency, low flow resistance, and high dust loading capacity with long life, low thickness, and goodstiffness for better filter construction. However, the prior technology has significant limitations.

[0128] For example, in order to have low resistance (e.g. within 30Pa at 30cm / s), a small thickness (e.g. within 1mm), and high dust loading capacity (e.g. 30g / m2at 30cm / s with ASHRAE dust terminal pressure of 150pa), the efficiency of the media using current technology would generally be low, ranging from 25% to 38% at 16.7cm / s flow rate. When the filtration efficiency is low, the particulate matter may not be removed well, and the filtration performance of the media may be poor. Under these conditions, a large number of particulate pollutants reach the activated carbon layer, which may reduce the effective area of activated carbon and reduce its gas adsorption efficiency and capacity. In the prior art, if the filtration efficiency is increased while the thickness and basis weight of the composite filter media are held constant, the resistance will generally increase and the dust loading capacity will generally be reduced. For example, if the efficiency is increased to more than 50%, the resistance will exceed 40Pa, and the dust loading capacity will be reduced to about 10g / m2or less.

[0129] The prior art practices also run into the problem of desirable high air permeability of the substrate contributing to carbon leakage of activated carbon. In order to reduce the resistance of the filter material, the substrate may then utilize high air permeability and low resistance, but if the substrate has high air permeability, carbon particles could leak through the substrate and fall off the composite filter media. In order to avoid this leakage problem, the prior art methods often chose a substrate with low air permeability or used large particle carbon. Yet, the substrate with low air permeability generally has greater resistance. The large particle carbon often increases the thickness of the filter material and often reduces adsorption efficiency compared to fine particle carbon. Both of the above schemes can have a negative impact on the overall performance of the composite filter media.

[0130] The inventive nanofiber composite technology provides high- performance filter materials compared to some prior art filter materials:

[0131] 1. Efficiency can be improved and dust loading capacity increased while maintaining low flow resistance and low thickness;

[0132] 2. Efficiency and thickness can remain constant while flow resistance would be reduced and dust loading capacity would be increased;

[0133] 3. Reduce the resistance and improve the efficiency while maintaining the same dust loading capacity and thickness;

[0134] 4. Maintain the same thickness while improving filtration efficiency, reducing flow resistance, and improving dust loading which greatly improves the overall filtration performance of the filter material while the thickness and stiffness of the filter material can be well controlled and guaranteed.

[0135] In some embodiments, the nanofibers are electrospun using needle or needleless spinning method, or other method. These nanofibers can be electrospun on a high permeability substrate on one side or both side, or alternatively nanofiber spun on a substrate and then compounded with the high permeability substrate, the nanofiber contained substrate is combined with activated carbon in the middle and melt blown or triboelectric media or fabric with nanofiber coating on one side or both side on the top, these layers are compounded by glue spraying, glue film transfer technic , ultra sound or powder glue heat lamination method.

[0136] In some embodiments the nanofibers can be selected from the group comprising PVDF, nylon, CA, PS, PAN, PI, PMIA, TPU, PEI, PLA, PES etc. and / or any combination thereof.

[0137] In at least one inventive process:

[0138] 1. the polymer materials, solvents w / or w / o additives are mixed and stirred to make a solution.

[0139] 2 The nanofiber is electrospun onto a support layer (e.g.Electrospinning parameters: flow rate 0.003-0.3 ml / min / needle, voltage 10- 70kv, DCD 10-30cm, ambient temperature and humidity 10-35°C, 15-45%).

[0140] 3. adsorbing material (e.g. activated carbon w / or w / o glue powder) is spray on the support layer coated with nanofiber,

[0141] 4. a top layer w / or w / o significant filtration efficiency and dust loading capacity layer is put on the top of adsorption layer having adsorbing material. This top layer can be meltblown, triboelectric media, or drylaid, wetlaid fabric w / or w / o nanofiber coating on one or both sides.

[0142] 5. In some embodiments the bonding method between each layer can be ultrasonic bonding, hot melt glue spray, glue powder then heat lamination, or film transfer glue lamination method.

[0143] In some embodiments the diameter of nanofibers is less than1mm, preferably less than 0.3mm, preferably less than 0.15mm. In some embodiments, the air flow resistance is 2-30pa at 5.33 cm / s, and in some embodiments the efficiency is 20-95% at 5.33 cm / s. In some embodiments the permeability of high permeability base material is 2000-5000 L / m2 / min, melt blown 10-50g, efficiency 10-95%, triboelectric materials 20-70g, efficiency 10- 95%.

[0144] In some embodiments, the total efficiency of the filter material is 30-99%, the dust loading capacity can reach 20-80g / m2, the air flow resistance can be controlled at 4-40Pa (at 5.33cm / s), the thickness is about 0.55-1.5mm, and the active carbon adsorbents is 50-700gsm.Example 1

[0145] As shown in Figure 1, a composite filter media comprises the nanofiber layer 1, the inner support layer 2 arranged on the lower and / or upper sides of the nanofiber layer 1, the nanofiber layer 1 filters and holds dust and other particles; the inner support layer 2 provides support for the nanofiber layer 1 and reduces the overall filling density of the nanofiber;

[0146] The nanofiber layer 1 included nanofibers with a diameter of Inm to 5000 nm, and the fiber diameter of the inner support layer 2 did not exceed 100pm.Example 2

[0147] As shown in Figure 2, the composite filter media comprises the nanofiber layers 11, 12, 13, 14, 15, 16 and the inner support layers 21, 22, 23, 24, 25 and the outer support layer 3 / 31 connected below the lowermost nanofiber layer 11 and the outer support layer 32 connected above the uppermost nanofiber layer 16. The inner support layers are used to support the nanofiber layers and reduce the overall filling density of nanofiber;

[0148] The nanofiber layers 11-16 include nanofibers with a diameter of Inm to 5000 nm, and the fiber diameter of the inner support layers 21-25 do not exceed 100pm ;

[0149] The number of the nanofiber layers need not be as many as shown but generally will include at least two with an inner support layer arranged between adjacent nanofiber layers.

[0150] The inner support layers 21-25 are any or the combination of the following: spunbonded nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven fabric and fiber mesh with a basis weight of less than 80g / m2;

[0151] The particle filtration efficiency of the downstream nanofiber layer is preferably greater than or equal to that of the adjacent upstream nanofiber layer;

[0152] The difference of particle filtration efficiency between the downstream nanofiber layer and the adjacent upstream nanofiber layer is less than 60%.

[0153] The nanofiber layer can comprise submicron fibers and micron fibers with a fiber diameter less than or equal to 5 pm; The fiber diameter of the nanofiber layer can have a single peak distribution with peak value within the diameter range of the nanometer size. The fiber diameter of the nanofiber layer can also have a double or more peak distribution with the first peak being within the diameter range of the nanometer size (5-100nm), and the other peaks within the diameter range of the submicron size and micron size.

[0154] The outer support layer 32 / 31 is used to provide strength and stiffness for the composite filter media. The outer support layer 32 / 31 which connected below the lowest layer of nanofiber layer 11 is the first outer support layer 31, and the outer support layer connected above the uppermost layer of nanofiber layer 16 is the second outer support layer 32; The outer support layer can also function as any or the combination of the following: a protection layer or an efficiency layer or a dust loading layer. The inner support layer can also function as any or the combination of the following: an efficiency layer or a dust loading layer or a separation layer.

[0155] The material of nanofibers and submicron and micron fibers is polymer or inorganic, and nanofibers are any of the following: PA6, PA56,PA66, PAI 010, PAN, PLA, PU, PVDF, PEI, PMIA, PS, PEO, PVA, CA, PLA, PC, PMMA, AI2O3, SiCE, ZrCL, glass fiber etc;

[0156] The nanofibers are continuous filaments or are discontinuous staple fibers;

[0157] The material of the inner support layers 21-25 are any one or combination of the following: PP, PET, PE, PA, PVDF, PAN, PS, PLA, PET / PE, PET / LMPET and glass fiber. When the inner support layer is bicomponent fiber, the polymer weight ratio of the skin layer and the core layer can be any one of the following: 30 / 70 to 70 / 30; or 20 / 80 to 80 / 20; or 10 / 90 to 90 / 10;

[0158] The fiber diameter of inner support layer(s) can be 0.3 pm to 100pm. The inner support layer(s) can have a monodisperse fiber diameter distribution or a poly-disperse fiber diameter distribution with a peak value between 0.3 p m and 100 p m.

[0159] The inner support layers can be any or the combination of the following: spunbonded nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven fabric and fiber mesh with a basis weight of less than 80g / m2.

[0160] Micron fibers are uniformly distributed staple fibers or continuous filaments. Micron fibers can be made of polymers or inorganic. Micron fibers can be any one or combination of the following: PA6, PA56, PA66, PAI 010, PAN, PLA, PU, PS, PVDF, PEI, PI, PMIA, PTFE, PMMA, CA, AI2O3, SiO2, ZrO2, PP, PE, PET, PET / PE, PET / LMPET and glass fibers;

[0161] In the nanofiber layer, the number ratio of nanofibers to micron fibers and submicron fibers can be 6: 1 to 600: 1, and the mass ratio can be 1 :99 to 10:1.Example 3

[0162] As shown in Figure 3, a preparation method of composite filter material can comprise the following steps:

[0163] SI. The nanofiber layer 11 is formed on the inner support layer 21 and the first outer support layer 31 by electrospinning. The nanofiber layer 11 includes nanofibers with a diameter of Inm to 5000 nm, and the inner support layer 21 can be any or the combination of the following: spunbonded nonwovenfabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown and / or fiber mesh with a fiber diameter of less than 100pm;

[0164] The number of the inner support layer was at least one, the thickness and basis weight of the inner support layers can be different, and the first outer support layer 31 can be any or the combination of the following: spunbonded nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven fabric, and / or fiber mesh with a fiber diameter of less than 100pm;

[0165] the nanofiber layers can be obtained by depositing nanofibers or simultaneously depositing nanofibers, microfibers and submicrofibers on the inner support layers through electrospinning method or the combination of electrospinning and other fiber laid down method such as airlaid, aerodynamic fiber dispersion and webforming methods. The fiber diameter of the micro fibers can be less than or equal to 100pm. the number ratio of the nanofibers to the micro fibers and / or the submicron fibers can be 6: 1 to 600: 1, and the mass ratio was 1 :99 to 10: 1;

[0166] The filtration efficiency of the nanofiber layer 1 preferably increased from top to bottom.

[0167] S2. The second outer support layer 32 can be placed above the top layer of the nanofiber layer 16. The nanofiber layer, the inner support layer, and the outer support layer can be combined together by hot pressing, glue bonding, and / or ultrasonic bonding to obtain composite filter medias.

[0168] The second outer support layer 32 can be any or the combination of the following: spunbonded nonwoven fabric, air laid nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven fabri or fiber mesh.Example 4

[0169] As shown in Figures 2 and 3, the preparation method of a composite filter media was as follows:

[0170] Step 1 : PVDF nanofiber layer 1 can be deposited on PET / PE bicomponent spunbonded substrate 2 with a thickness of 0.09mm and a basis weight of 15g / m2(wherein the skin layer was PE and the core layer was PET) by electrospinning, and the composite filter media of the nanofiber and spunbondedsubstrate with filtration efficiency of 30%, 50%, 70%, 80% and 90% are prepared respectively; PVDF nanofiber layer 1 can be deposited on PET / PE bicomponent spunbonded substrate 2 with a thickness of 0.16mm, a basis weight of 35g / m2(wherein the outer layer was PE and the core layer was PET) by electrospinning, and a composite filter media of nanofiber and spunbonded substrate with a filtration efficiency of 95% was prepared.

[0171] Step 2: The PET / PE bicomponent spunbonded substrate (the second outer support layer 32) and nanofiber media with filtration efficiency of 30% which is prepared in step 1, nanofiber media with filtration efficiency of 50% which is prepared in step 1, nanofiber media with filtration efficiency of 70% which is prepared in step 1, nanofiber media with filtration efficiency of 80% which is prepared in step 1, nanofiber media with filtration efficiency of 90% which is prepared in step 1, nanofiber media with filtration efficiency of 95% which is prepared in step 1, are sequentially arranged from top to bottom. Then the sequentially arranged composite filter medias are compounded by a hot pressing roller with a temperature of 145°C and a roller gap of 0.5mm to obtain nanofiber composite filter media with high efficiency and low pressure drop.

[0172] The nanofiber composite filter media has a efficiency of 99.99% and pressure drop of 142. IPa for NaCl poly-disperse aerosols with a median mass diameter of 0.26pm and a median number diameter of 75 nm at a flow rate of 5.33cm / s. The composite filter media and the single-layer nanofiber composite filter media with efficiency of 99.99% were continuously loaded with poly-disperse DEHS aerosol at a fixed concentration, respectively; and the curves of pressure drop of the two composite filter medias versus the loading of DEHS were obtained. The structure was shown in Figure 2. The nanofiber layer 1 consisted of six layers, and 11 was the first nanofiber layer, 12 was the second nanofiber layer, 13 was the third nanofiber layer, 14 was the fourth nanofiber layer, 15 was the fifth nanofiber layer, 16 was the sixth nanofiber layer; the inner support layer 2 includes five layers, 21 was the first inner support layer, 22 was the second inner support layer, 23 was the third inner support layer, 24 was the fourth inner support layer, 25 was the fifth inner support layer; 31 was the first outer support layer, and 32 was the second outer support layer. The diameter distribution of electrospinning nanofiber media was shown in Figure 4, and dustholding capacity and single-layer electrospun nanofiber media was shown in Figure 5.Example 5

[0173] Step 1 : Pressure sensitive adhesive (PSA) can be sprayed online on PET spunbonded substrate which has a basis weight of around 20g / m2and a thickness of around 0.12mm; The spraying amount of PSA can be around 2.5g / m2. During the unconsolidated time of PSA, PVDF nanofiber layer 1 (Figure 1) was deposited on the PET spunbonded substrate by electrospinning, and the composite filter media of nanofibers and spunbonded substrate with filtration efficiency of 90% and 95% were obtained respectively;

[0174] PSA can be sprayed online on PET spunbonded substrate which has a basis weight of around 35g / m2and a thickness of around 0.16mm; The spraying amount of PSA can be around 2.5g / m2. During the unconsolidated time of PSA, PVDF nanofiber layer 1 (Figure 1) was deposited on the PET spunbonded substrate by electrospinning, and the composite filter media of nanofibers and spunbonded substrate with filtration efficiency of 98% was obtained;

[0175] Step 2: PSA was sprayed online on the lower surface of the PET spunbonded substrate (the second outer support layer 32) with a thickness of 0.16 mm and a weight of 35 g / m2; and the spraying amount of PSA was 2.5g / m2; Then, the PET spunbonded substrate, the composite filter media prepared in step 1 with filtration efficiency of 90% and the composite filter media prepared in step 1 with filtration efficiency of 95% and a basis weight of its support layer was 20g / m2, and the composite filter media prepared in step 1 with filtration efficiency of 98% and a basis weight of its support layer can be 35g / m2are arranged from top to bottom. The nanofiber layer 1 in each layer can be placed between two adjacent spunbonded substrates 2. The composite filter media arranged in sequence are compounded by the hot pressing roller with the temperature of 140°C and the roller gap of 0.4 mm. Finally, the composite filter media with high efficiency and low pressure drop can be obtained.

[0176] The nanofiber composite filter media has a filtration efficiency of 99.99% and pressure drop of 119.5Pa for NaCl poly-disperse aerosols with a median mass diameter of 0.26pm and a median number diameter of 75 nm at aflow rate of 5.33cm / s. The nanofiber composite filter media and a PTFE composite filter media with 99.99% efficiency were continuously loaded with cigarette smoke at a fixed concentration and air flow rate. The change curve of pressure drop of the two composite filter medias with loading of cigarette smoke was obtained. The structure is shown in Figure 6. The nanofiber layer 1 includes three layers, 11 is the first nanofiber layer, 12 is the second nanofiber layer, 13 is the third nanofiber layer; the inner support layer 2 includes two layers, 21 is the first micron fiber layer, 22 is the second micron fiber layer; 31 is the first outer support layer and 32 is the second outer support layer. The diameter distribution of nanofiber composite filter media is shown in Figure 6, and the dust loading behavior of the nanofiber composite filter media prepared in this example vs PTFE composite filter media is shown in Figure 7.Example 6

[0177] As shown in Figures 3, a preparation method of composite filter material can comprise the following steps:

[0178] Step 1 (Figure 1): Nanofibers and submicron and optionally microfibers were simultaneously deposited on the PET / PE spunbonded substrate 2 with a thickness of 0.12mm and a basis weight of 20g / m2(wherein the skin layer was PE, the core layer was PET, and the weight of the skin layer PE accounts for about 40%). The composite filter media of nanofiber layer 1 and spunbonded substrate 2 with filtration efficiency of 50%, 70%, and 90% were prepared respectively; PVDF nanofiber layer 1 was deposited online on PET / PE spunbonded substrate 2 with a thickness of 0.16mm and a basis weight of 35g / m2(wherein the skin layer is PE, the core layer is PET, and the weight of the skin layer PE accounts for about 40%) to obtain a combined composite filter media of nanofiber layer 1 and spunbonded substrate 2 with a filtration efficiency of 99%.

[0179] Step 2: the PET / PE bicomponent spunbonded substrate, the composite filter media prepared in step 1 with filtration efficiency of 50%, the composite filter media prepared in step 1 with filtration efficiency of 70%, the composite filter media prepared in step 1 with filtration efficiency of 90%, the composite filter media made in step 1 with filtration efficiency of 99% and a basis weight of its support layer around 35g / m2can be arranged from top tobottom. The nanofiber layer 1 can be placed between two adjacent spunbonded substrates 2. The composite filter media arranged in sequence can be compounded by the hot pressing roller with the temperature of 145°C and the roller gap of 0.4 mm. Finally, the composite filter media with high efficiency and low pressure drop can be obtained.

[0180] The nanofiber composite filter media can have a filtration efficiency of 99.99% and pressure drop of 124.2Pa for NaCl poly-disperse aerosols with a median mass diameter of 0.26pm and a median number diameter of 75 nm at a flow rate of 5.33cm / s. The continuous loading test of NaCl polydisperse aerosol with the median mass diameter of 0.26pm and number median diameter of 75nm, was respectively conducted for the composite filter media, PTFE membrane composite filter media produced by a Japanese company with 99.95% efficiency and superfine glass fiber composite filter media produced by an American company with 99.98% efficiency. The change curves of pressure drop of the three composite filter medias with the loading time were obtained, as shown in Figure 9;

[0181] The structure is shown in Figure 8. The nanofiber layer 1 includes 4 layers, 11 is the first nanofiber layer, 12 is the second nanofiber layer, 13 is the third nanofiber layer, 14 is the third nanofiber layer; the inner support layer 2 includes 3 layers, 21 is the first micron fiber layer, 22 is the second micron fiber layer, 23 is the third micron fiber layer; 31 is the first outer support layer, and 32 is the second outer support layer.Example 7

[0182] A nanofiber air composite filter media, its preparation method includes the following steps:

[0183] 1. A kind of polymer was added to the solvent, and stirred until fully dissolved, and a polymer solution A with a mass percent concentration of about 12% is obtained.

[0184] 2. Using an electrospinning platform, the nanofiber layer is deposited on a PET spunbonded substrate with a thickness of 0.13mm and a weight of 20g / m2by electrospinning to obtain the nanofiber composite filter media;

[0185] 3. The electron microscope image obtained by scanning electron microscope is shown in Fig. 10. The minimum fiber diameter of nanofibers is 47 nm, the maximum fiber diameter is 170 nm, and the average fiber diameter is 90 nm. The loftiness (void volume) of the nanofiber layer is 75%.

[0186] 4. Test the air flow resistance and efficiency of the nanofiber composite filter media at the flow rate of 5.33cm / s with 0.3pm NaCl polydisperse aerosol, the composite filter media has efficiency of 99%, and pressure drop is 70pa.

[0187] 5. The nanofiber composite filter media is continuously loaded with polydisperse NaCl aerosol at a fixed dust concentration, and the change curve of pressure drop of the composite filter media with the NaCl load is obtained, as shown in Figure 16.Example 8

[0188] A multi-component nanofiber composite filter media, the preparation method of which comprises the following steps:

[0189] 1. The polymer 1 was added to the solvent, and was stirred until fully dissolved to obtain polymer solution A with a mass percentage concentration of about 18%.

[0190] 2. The polymer 2 was added to the solvent, and was stirred until fully dissolved to obtain polymer solution B with a mass percentage concentration of about 11%.

[0191] 3 Two needle electrospinning platforms were prepared and the needle was placed in the opposite direction. And solution A was placed on #1 spinning platform and solution B was placed on #2 spinning platform; The mass ratio of large diameter nanofiber to fine nanofibers is about 85: 15 for spinning.

[0192] 4. PET spunbonded substrate with a thickness of 0.13mm and a basis weight of 20g / m2was used to receive the nanofiber layer and also used on top to protect the nanofiber layer as shown in Figure 11. Two electrospinning devices were opened simultaneously for spinning, and multicomponent nanofiber composite filter media are prepared online.

[0193] 5. The multi-component nanofiber mixed composite filter media prepared in step 4 was tested by scanning electron microscope, and SEM picture is shown in Figure 12; The minimum fiber diameter of ultrafine nanofibers is 58.9 nm, the maximum fiber diameter is 243 nm, and the average fiber diameter is 128 nm; The minimum diameter of large diameter nanofibers is 793 nm, the maximum fiber diameter is 829 nm, and the average fiber diameter is 811 nm. The bulkiness of the multi-component nanofiber composite filter media is 94%.

[0194] 6. The multi-component nanofiber composite filter media prepared in step 4 was tested for pressure drop and efficiency at the flow rate of 5.33cm / s with 0.33 p m NaCl polydisperse aerosol. Compared with Example 7, under the same test conditions, when the efficiency reaches 99%, the pressure drop of multi-component nanofibers composite filter media is 50 pa, which decreases by 28%.

[0195] 7 The multi-component nanofiber composite filter media is continuously loaded with polydisperse NaCl aerosol at a fixed dust concentration, and the change curve of pressure drop of the composite filter media with the NaCl load is obtained, as shown in Figure 16.Example 9

[0196] A multi-component nanofiber composite filter media, the preparation method of which comprises the following steps:

[0197] 1. The polymer 3 was added to the solvent, and was stirred until fully dissolved to obtain polymer solution C with a mass percentage concentration of about 25%.

[0198] 2. The polymer 4 was added to the solvent, and was stirred until fully dissolved to obtain polymer solution D with a mass percentage concentration of about 15%.

[0199] 3 Two needle electrospinning platforms were prepared and the needle is placed in the opposite direction. And solution C was placed on #1 spinning platform and solution D was placed on #2 spinning platform. The mass ratio of large diameter nanofiber to fine nanofibers is 80:20 for spinning.

[0200] 4. PET spunbonded substrate with a thickness of 0.13mm and a basis weight of 20g / m2was used to receive the nanofiber layer; Twoelectrospinning devices were opened simultaneously for spinning, and multicomponent nanofiber composite filter media are prepared online.

[0201] 5. The multi-component nanofiber mixed composite filter media prepared in step 4 was tested by scanning electron microscope, and SEM picture is shown in Figure 13; The minimum fiber diameter of ultrafine nanofibers is 40 nm, the maximum fiber diameter is 160nm, and the average fiber diameter is 100 nm; The minimum diameter of large diameter nanofibers is 1.1pm, the maximum fiber diameter is 1.9pm, and the average fiber diameter is 1.5pm. The bulkiness of the multi-component nanofiber composite filter media is 93%.

[0202] 6. The multi-component nanofiber composite filter media prepared in step 4 was tested for pressure drop and efficiency at the flow rate of 5.33cm / s with 0.33 p m NaCl polydisperse aerosol. Compared with Example 7, under the same test conditions, when the efficiency reaches 99%, the pressure drop of multi-component nanofibers composite filter media is 42 pa.

[0203] 7. The multi-component nanofiber composite filter media is continuously loaded with polydisperse NaCl aerosol at a fixed dust concentration, and the change curve of pressure drop of the composite filter media with the NaCl load is obtained, as shown in Figure 16.

[0204] A multi-component nanofiber composite filter media, the preparation method of which comprises the following steps:

[0205] 1. The polymer 3 was added to the solvent, and was stirred until fully dissolved to obtain polymer solution E with a mass percentage concentration of about 20%.

[0206] 2. The polymer 4 was added to the solvent, and was stirred until fully dissolved to obtain polymer solution F with a mass percentage concentration of about 10%.

[0207] 3. Two needle electrospinning platforms were prepared and the needle is placed in the opposite direction. And solution E was placed on #1 spinning platform and solution F was placed on #2 spinning platform; The mass ratio of large diameter nanofiber to fine nanofibers is 60:40 for spinning.

[0208] 4. PET spunbonded substrate with a thickness of 0.13mm and a basis weight of 20g / m2is used to receive the nanofiber layer; Twoelectrospinning devices were opened simultaneously for spinning, and multicomponent nanofiber composite filter media are prepared online.

[0209] 5. The multi-component nanofiber mixed composite filter media prepared in step 4 was tested by scanning electron microscope, and SEM picture is shown in Figure 15; The minimum fiber diameter of ultrafine nanofibers is 48 nm, the maximum fiber diameter is 140nm, and the average fiber diameter is 90 nm; The minimum diameter of large diameter nanofibers is 1.5pm, the maximum fiber diameter is 2.2pm, and the average fiber diameter is 1.85pm. The bulkiness of the multi-component nanofiber composite filter media is 91%.

[0210] 6. The multi-component nanofiber composite filter media prepared in step 4 was tested for pressure drop and efficiency at the flow rate of 5.33cm / s with 0.3 p m NaCl polydisperse aerosol. Compared with Example 7, under the same test conditions, when the efficiency reaches 99%, the pressure drop of multi-component nanofibers composite filter media is 37 Pa.

[0211] 7 The multi-component nanofiber composite filter media is continuously loaded with polydisperse NaCl aerosol at a fixed dust concentration, and the change curve of pressure drop of the composite filter media with the NaCl load is obtained, as shown in Figure 16.Example 10

[0212] A multi-component nanofiber composite filter media, the preparation method of which comprises the following steps:

[0213] 1. Pressure sensitive adhesive (PSA) was sprayed online onPET spunbonded substrate 2A which has a basis weight of 20g / m2and a thickness of 0.12mm; The amount of PSA is 2.5g / m2. During the unconsolidated (open) time of PSA, Large diameter nanofibers and Ultrafine nanofibers are deposited simultaneously on the PET spunbonded substrate by electrospinning, and the composite filter media of nanofibers and spunbonded substrate with efficiency of 80% and 95% were obtained respectively; wherein the mass ratio of large diameter nanofiber to fine nanofibers is 75:25.

[0214] PSA is sprayed online on PET spunbonded substrate 2A which has a basis weight of 35g / m2and a thickness of 0.16mm; The spraying amount of PSA is 2.5g / m2. During the unconsolidated time of PSA, Large diameternanofibers and Ultrafine nanofibers are deposited simultaneously on the PET spunbonded substrate by electrospinning, and the composite filter media of nanofibers and spunbonded substrate with efficiency of 99% is obtained; wherein the mass ratio of large diameter nanofiber to fine nanofibers is 60:40.

[0215] 2. PSA was sprayed online on the lower surface of the PET spunbonded substrate with a thickness of 0.16 mm and a weight of 35 g / m2; and the spraying amount of PSA was 2.5g / m2; Then, the PET spunbonded substrate, the composite filter media prepared in step 1 with filtration efficiency of 80%, the composite filter media prepared in step 1 with filtration efficiency of 95% and its support layer has a basis weight of 20g / m2and a thickness of 0.12mm, the composite filter media prepared in step 1 with filtration efficiency of 99% and its support layer has a basis weight of 35g / m2and a thickness of 0.16mm, are arranged from top to bottom. The nanofiber layer in each layer is placed between two adjacent spunbonded substrates. The composite filter media arranged in sequence are compounded by the hot pressing roller with the temperature of 140°C and the roller gap of 0.4 mm. Finally the composite filter media with high efficiency and low pressure drop is obtained. The structure diagram is shown in Figure 17.

[0216] The nanofiber composite filter media has a filtration efficiency of 99.99% and pressure drop of 1 lOPa for NaCl poly-disperse aerosols with a median mass diameter of 0.26pm and a median number / number diameter of 75 nm at a flow rate of 5.33cm / s. The composite filter media and PTFE membrane composite filter media produced by a Japanese company with 99.95% efficiency were continuously loaded with cigarette smoke at a fixed concentration and air flow rate. The change curves of pressure drop of the two medias with the loading time were obtained, as shown in Figure 18;Regarding Figures 11 and 17:

[0217] 11 A- The first multi-component nanofiber layer 80% ; 12A- The second multi-component nanofiber layer 95% ; 13 A-The third multi-component nanofiber layer 99% ;

[0218] 21 A-The first inner support layer 20gsm ; 22 A-The second inner support layer 20gsm J

[0219] 31 A- The first outer support layer 35gsm J 32A-The second outer support layer 35gsm JExample 11

[0220] The composite filter media comprised of needle-punched triboelectric media, activated carbon, PVDF nanofiber and PET substrate fabric. The needle-punched triboelectric media has the basis weight of 47.5 gsm (grams / per square meter), a thickness of 0.504mm, flow resistance of 4.63 Pa at the air flow rate of 16.7cm / s, and filtration efficiency of 39.81% at the air flow rate of 26.25cm / s. PET dry- laid substrate nonwoven has the basis weight of 70 gsm, a thickness of 0.38mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and flow resistance of 0.75Pa, the filtration efficiency of 5.82% at the air flow rate of 32L / min. PVDF nanofiber with a diameter of 0.14um (using electron scanning microscope), flow resistance of 4.15 Pa and filtration efficiency of 55.36% (flow rate: 32L / min) was spun onto PET substrate nonwoven by electrostatic spinning method.

[0221] Activated carbon are 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%. During the preparation, PVDF nanofiber was attached to dry PET substrate material, sprayed glue and carbon (180 gsm), and then composited with needle-punched triboelectric media. The resulted composite filter media was denoted as NF-1, with a total basis weight of 319 gsm, thickness of 1.32 mm, filtration efficiency of 72.2%, flow resistance of 27 Pa at the air flow rate of 16.7cm / s, and dust loading capacity of 80.64 gsm. Compared with Example 21 below, it has a similar flow resistance but 36% higher filtration efficiency and 101% higher of dust loading capacity.Example 12

[0222] The composite filter media can be comprised of needle-punched triboelectric media, activated carbon, Nylon nanofiber and PET substrate fabric. The needle-punched triboelectric media is basis weight of 38.4 gsm, with a thickness of 0.398 mm, flow resistance of 3.8 Pa and filtration efficiency of 38.4% at the air flow rate of 16.7cm / s. PET substrate fabric are basis weight of 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and flow resistance of 0.75Pa, filtration efficiency of 5.82% atthe air flow rate of 32L / min. Nylon nanofiber with a diameter of 0.1 um (use electron scanning microscope), flow resistance of 4.15 Pa and filtration efficiency of 55.36% at the air flow rate of 32L / min, was spun onto PET substrate nonwoven by electrostatic spinning method. Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0223] During the preparation, Nylon nanofiber was attached to PET substrate fabric, sprayed glue and carbon (90 gsm), and then composited with needle-punched triboelectric media. The resulted composite filter media was denoted as NF-2, with a total basis weight of 261 gsm, thickness of 1.32 mm, flow resistance of 21.55 Pa, filtration efficiency of 63.72% (flow rate: 16.7cm / s), and dust loading capacity of 63.61 gsm (flow rate: 0.3 m / s). Compared with Example 22 below, it has a 36% lower flow resistance, a similar filtration efficiency and 57% higher of dust loading capacity.Example 13

[0224] The composite filter media comprised of melt-blown fabric, activated carbon, PAN nanofiber and PET substrate fabric. The adoptive melt- blown fabric is basis weight of 16.5 gsm, with a thickness of 0.167 mm, flow resistance of 6.77 Pa and filtration efficiency of 42.8% (flow rate: 16.7cm / s). PET substrate fabric has basis weight of 50 gsm, thickness of 0.38 mm, tensile strength of 80N / 5cm (MD), 60N / 5cm (CD), and flow resistance of 0.75Pa, filtration efficiency of 5.82% at the air flow rate of 32L / min. PAN nanofiber with a diameter of 0.2um (use electron scanning microscope), flow resistance of 2.7 Pa and filtration efficiency of 33.5% (flow rate: 32L / min) was spun onto PET substrate fabric by electrostatic spinning method. Activated carbon is 60-80 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0225] During the preparation, PAN nanofiber was attached to PET substrate fabric, sprayed glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media has a total basis weight of 180 gsm, thickness of 0.818 mm, flow resistance of 17.7 Pa, filtration efficiency of 66.35% (flow rate: 16.7cm / s), and dust loading capacity of 19.77 gsm. Compared with Example 23 below, it has similar flow resistance and dust loading capacity while a 73.7% higher of filtration efficiency.Example 14

[0226] The composite filter media comprised of melt-blown fabric, activated carbon, PS nanofiber and PET substrate fabric. The melt-blown fabric is basis weight of 16.5 gsm, with a thickness of 0.167 mm, flow resistance of 4.3 Pa and filtration efficiency of 27.23% (flow rate: 16.7cm / s). PET substrate fabric is basis weight of 50 gsm, with a thickness of 0.30 mm, tensile strength of 80N / 5cm (MD), 60N / 5cm (CD), and flow resistance of 0.75Pa, filtration efficiency of 5.82% (flow rate: 32L / min). PS nanofiber with average diameter of 0.25 um (under electron microscope), flow resistance of 3.9 Pa and filtration efficiency of 46.1% (flow rate: 32L / min) was spun onto PET substrate nonwoven by electrostatic spinning method. Activated carbon is 60-80 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0227] During the preparation, PS nanofiber was attached to PET substrate fabric, sprayed glue and carbon (180 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NF -4, with a total basis weight of 270 gsm, thickness of 0.823mm, flow resistance of 21.6 Pa, filtration efficiency of 69.13% (flow rate: 16.7cm / s), and dust loading capacity of 19.49 gsm. Compared with Example 23 below, it has a 30% higher flow resistance and 81.6% higher of filtration efficiency while a similar dust loading capacity.Example 15

[0228] The composite filter media can be comprised of melt-blown fabric, activated carbon, PVDF nanofiber and PET substrate fabric. The adoptive melt-blown fabric is basis weight of 14.6 gsm, with a thickness of 0.19 mm, flow resistance of 2.7 Pa and filtration efficiency of 10.37% (flow rate: 16.7cm / s). PET substrate fabric is 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and flow resistance of 0.75Pa, filtration efficiency 5.82% (flow rate: 32L / min). PVDF nanofiber with a diameter of 0.1 um (electron microscope), flow resistance of 3.6 Pa and filtration efficiency of 58.7% (flow rate: 32L / min) was spun onto PET substrate fabric by electrostatic spinning method. Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0229] During the preparation, PVDF nanofiber was attached to PET substrate fabric, sprayed glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NF-5, with a total basis weight of 165 gsm, thickness of 0.9 mm, flow resistance of 10.7 Pa, filtration efficiency of 40.16% (flow rate: 16.7cm / s), and dust loading capacity of 19.93 gsm. Compared with comparative example #3, it has a 22.7% lower flow resistance, a similar filtration efficiency and dust loading capacity.Example 16

[0230] The composite filter media can be comprised of melt-blown fabric, activated carbon, PVDF nanofiber and PET substrate fabric. The adoptive melt-blown fabric is basis weight of 10.4 gsm, with a thickness of 0.18 mm, resistance of 8.6 Pa and filtration efficiency of 25.76% (flow rate: 16.7cm / s). PET substrate fabric is basis weight of 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and resistance of 0.75Pa, filtration efficiency of 5.82% (flow rate: 32L / min). PVDF nanofiber with a diameter of 0.18 um (electron microscope), resistance of 3.9 Pa and filtration efficiency of 62.4% (flow rate: 32L / min) was spun onto PET substrate nonwoven by electrostatic spinning method. Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0231] During the preparation, PVDF nanofiber was attached to PET substrate fabric, sprayed glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NF -6, with a total basis weight of 175.4 gsm, thickness of 0.568 mm, resistance of 17.6 Pa, filtration efficiency of 44.45% (flow rate: 16.7cm / s), and dust loading capacity of 11.7 gsm. Compared with comparative example #4, it has a 12.2% lower resistance, a similar filtration efficiency and a 117% higher of dust loading capacity.Example 17

[0232] The composite filter media can be comprised of melt-blown fabric, activated carbon, TPU nanofiber and PET substrate fabric. The adoptive melt-blown fabric is basis weight of 10.4 gsm, with a thickness of 0.18 mm, resistance of 8.6 Pa and filtration efficiency of 25.76% (flow rate: 16.7cm / s).PET substrate fabric is basis weight of 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and resistance of 0.75Pa, filtration efficiency of 5.82% (flow rate: 32L / min). TPU nanofiber with a diameter of 0.1 um (electron microscope), resistance of 3.6 Pa and filtration efficiency of 58.7% (flow rate: 32L / min) was sprayed onto PET substrate nonwoven by electrostatic spinning method. Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0233] During the preparation, TPU nanofiber was attached to PET substrate fabric, sprayed glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NF -7, with a total basis weight of 175.4 gsm, thickness of 0.568 mm, resistance of 20.85 Pa, filtration efficiency of 56.22% (flow rate: 16.7cm / s), and dust loading capacity of 11.6 gsm. Compared with comparative example #5, it has a 35.4% lower resistance, a similar filtration efficiency and a 93% higher of dust loading capacity.Example 18

[0234] The composite filter media can be comprised of melt-blown fabric, activated carbon, PAN nanofiber and PET substrate fabric. The adoptive melt-blown fabric is basis weight of 19.7 gsm, with a thickness of 0.13 mm, resistance of 4.3 Pa and filtration efficiency of 16.54% (flow rate: 16.7cm / s). PET substrate fabric is basis weight of 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and resistance of 0.75Pa, filtration efficiency 5.82% (flow rate: 32L / min). PAN nanofiber with a diameter of 0.15 um (electron microscope), resistance of 3.9 Pa and filtration efficiency of 62.4% (flow rate: 32L / min) was spun onto PET substrate nonwoven by electrostatic spinning method. Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0235] During the preparation, PAN nanofiber was attached to PET substrate fabric, sprayed glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NF-8, with a total basis weight of 184.7 gsm, thickness of 0.518 mm, resistance of 12.4 Pa, filtration efficiency of 42.31% (flow rate: 16.7cm / s), and dust loading capacity of 11.5 gsm. Compared with comparative example #4, it has a 38.2%lower resistance, a similar filtration efficiency and a 113% higher of dust loading capacity.Example 19

[0236] The composite filter media can be comprised of melt-blown fabric, activated carbon, TPU nanofiber and PET substrate fabric. The adoptive melt-blown fabric is basis weight of 19.7 gsm, with a thickness of 0.13 mm, resistance of 4.3 Pa and filtration efficiency of 16.54% (flow rate: 16.7cm / s). PET substrate fabric is basis weight of 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and resistance of 0.75Pa, filtration efficiency 5.82% (flow rate: 32L / min). TPU nanofiber with a diameter of 0.15 um (electron microscope), resistance of 3.6 Pa and filtration efficiency of 58.7% (flow rate: 32L / min) was sprayed onto PET substrate fabric by electrostatic spinning method. Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0237] During the preparation, TPU nanofiber was attached to PET substrate fabric, sprayed glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NF -9, with a total basis weight of 184.7 gsm, thickness of 0.518 mm, resistance of 17.2 Pa, filtration efficiency of 50.49% (flow rate: 16.7cm / s), and dust loading capacity of 10.7 gsm. Compared with comparative example #5, it has a 46.7% lower resistance, a similar filtration efficiency and a 78% higher of dust loading capacity.Example 20

[0238] The composite filter media can be comprised of melt-blown, activated carbon, PA nanofiber and PET nonwoven substrate. The melt-blown layer has a basis weight of 14.6 gsm, with a thickness of 0.19 mm, resistance of 2.7 Pa and filtration efficiency of 10.37% (flow rate: 16.7cm / s). PET nonwoven substrate has basis weight of 50 gsm, thickness of 0.30 mm, tensile strength of 80N / 5cm (MD), 60N / 5cm (CD), and flow resistance of 0.75Pa, filtration efficiency of 5.82% at flow rate of 32L / min. PA nanofiber with a average fiber diameter of 0.1 um (under electron microscope), resistance of 3.9 Pa and filtration efficiency of 62.4% at the flow rate of 32L / min was put onto PETnonwoven substrate by electrostatic spinning method. Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0239] During the composite media preparation, PA nanofiber was first attached to PET nonwoven substrate, then a layer of glue was sprayed on the substrate, followed by laying down 90 gsm activated carbon particle , then another layer of glue was sprayed on the carbon layer, to composite with melt- blown layer together.

[0240] The resulted composite filter media was denoted as NF- 10, has a total basis weight of 179.6 gsm, thickness of 0.578 mm, resistance of 9.35 Pa, filtration efficiency of 35.48% at the flow rate of 16.7cm / s, and dust loading capacity of 14.9 gsm with ASHRAE dust. Compared with Comparative example #5, it has a 53.4% lower flow resistance, a 17% lower filtration efficiency and a 176% higher of dust loading capacity.Example 21

[0241] Reference 21 was denoted as NFR-1 and shows the composite filter media comprise 20gsm PET nonwoven, 18gsm meltblown, 205gsm activated carbon and 70gsm PET nonwoven support layer plus glues in between layers to bond all layers together, with a total basis weight of 340gsm, thickness of 1.1 mm, resistance of 28.3Pa (flow rate: 0.167 m / s), filtration efficiency of 52% (flow rate: 0.167 m / s), and dust loading capacity of 40gsm (flow rate: 0.3 m / s).Example 22

[0242] Reference 22 was denoted as NFR-2 and shows the composite filter media comprise 20gsm PET nonwoven, 25gsm meltblown, 340gsm activated carbon and 70gsm PET nonwoven support layer plus glues in between layers to bond all layers together, with a total basis weight of 485 gsm, thickness of 1.4 mm, resistance of 33.4 Pa (flow rate: 0.167 m / s), filtration efficiency of 58% (flow rate: 0.167m / s), and dust loading capacity of 40 gsm (flow rate: 0.3 m / s).Example 23

[0243] Reference 23 was denoted as NFR-3 and shows the composite filter media comprise 18gsm meltblown as top layer, 60gsm carbon particle in the middle, and 50gsm PET substrate, with a total basis weight of 165 gsm, thickness of 0.5435 mm, resistance of 13.8 Pa, filtration efficiency of 38.26% (flow rate: 16.7cm / s), and dust loading capacity of 20.32 gsm.Example 24

[0244] Reference 24 shows the composite filter media comprised of melt-blown fabric, activated carbon and PET substrate fabric. The adoptive melt- blown fabric is basis weight of 14.6 gsm, with a thickness of 0.12 mm, resistance of 15.7 Pa and filtration efficiency of 36.79% (flow rate: 16.7cm / s). PET substrate fabric is basis weight of 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and resistance of 0.75Pa, filtration efficiency 5.82% (flow rate: 32L / min). Activated carbon is 30-60 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0245] During the preparation, PET substrate fabric was sprayed with glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NFR-4, with a total basis weight of 179.6gsm, thickness of 0.508mm, resistance of 20.05Pa, filtration efficiency of 42.74% (flow rate: 16.7cm / s), and dust loading capacity of 5.4 gsm.Example 25

[0246] Reference 25 shows the composite filter media comprised of melt-blown fabric, activated carbon and PET substrate fabric. The adoptive melt- blown fabric is basis weight of 16.3 gsm, with a thickness of 0.18 mm, resistance of 18 Pa and filtration efficiency of 44.78% (flow rate: 16.7cm / s). PET substrate fabric is basis weight of 70 gsm, with a thickness of 0.38 mm, tensile strength of 160N / 5cm (MD), 60N / 5cm (CD), and resistance of 0.75Pa, filtration efficiency 5.82% (flow rate: 32L / min). Activated carbon is 60-80 mesh with an iodine value of 1000 and hardness of 98, ash of 5%.

[0247] During the preparation, PET substrate fabric was sprayed with glue and carbon (90 gsm), and then composited with melt-blown fabric. The resulted composite filter media was denoted as NFR-5, with a total basis weightof 181.3 gsm, thickness of 0.568 mm, resistance of 32.3 Pa, filtration efficiency of 53.89% (flow rate: 16.7cm / s), and dust loading capacity of 6.0 gsm.

[0248] The nanofiber composite filter material allows the uses of high permeability substrate, which can reduce the overall resistance of the filter material, save energy and being environmentally friendly; Experiments show that the carbon leakage of media using nanofiber coated substrate is significantly less than that using non nanofiber coated substrate. The test data are as following:Test conditions: 60-80- mesh size activated carbon, 94 m / h, 30 min.

[0249] Therefore, carbon of smaller particles with larger carbon surface area and better adsorption performance can be used in nanofiber composite filter media. The selection of carbon with small particles can also reduce the thickness of the composite filter media, so the filter element can accommodate more composite filter media. When the composite filter media area is large, the flow resistance of the filter element will be reduced, and the service life of the filter element will be prolonged. At the same time, when the thickness of filter material is reduced, it is usually more conducive to the filter element design and manufacture.

[0250] In at least one embodiment, an air filter material design containing nanofibers wherein:

[0251] 1. The diameter of nanofibers is less than lum (0.3um),

[0252] 2. The air permeability of the substrate is more than800L / min (2000L / min),

[0253] 3. The filtration efficiency of nanofibers is between 10-95%;

[0254] In at least one embodiment, the air filter material design containing nanofibers includes an activated carbon particle size of 30-100;

[0255] In at least one embodiment, the design of the air filter material containing nanofibers includes an efficiency of 95-99.95%; Resistance 25-lOOpa, dust loading capacity 10-100gsm at 16.7cm / s flow rate, terminal pressure of two times of initial pressure drop.

[0256] In at least one embodiment, nanofibers can be made of polymer materials which are dissolved in solvents and mixed with functional and / or charge additives. Polymers can be Nylon, PVDF, PAN, PES, TPU, PS. Solvent can be formic acid, DMAC, DMF. Additives can be LiCl, KC1, antibacterial agents.

[0257] In at least one embodiment, the solution forms nanofibers by electrospinning with voltage of 10-70kv, DCD 10-30cm, flow rate of 0.01- O.lml / min / needle.

[0258] In at least one embodiment, nanofibers are spun on the substrate and then composited with activated carbon, melt blown, triboelectric media, or other electrostatic charged materials or other materials. The composite process can use glue spraying, glue powder or film transfer glue bonding technology.

[0259] In at least one embodiment, nanofibers and / or other components are added with antibacterial and antiviral functions and VC release functions. In embodiments, the nanocomposites containing nanofibers have stronger functions.

[0260] Nanofiber composite filter material as described in the present disclosure can be used in a number of filtration applications. For example, a pleated filter element 2500 is shown in Figure 25. In one example, the pleated filter element 2500 can be used in automotive or other motor vehicle applications. The pleated filter element 2500 includes a media pack 2502 of pleated media 2504 enclosed in a frame 2506. In one example, a form factor is rectangular, as shown in Figure 25, although the invention is not so limited.

[0261] Another example of a filtration product using nanofiber composite filter material as described in the present disclosure is shown in Figure 26. A multi-V style element 2600 is shown in Figure 26, including a number of pleat regions 2602 arranged on a frame 2604. The frame 2604 includes a number of inlets 2606 that accept pleats of filtration media 2608. The filtration media pleats 3008 include nanofiber composite filter material as described in the present disclosure.

[0262] Another example of a filtration product 2700 using nanofiber composite filter material as described in the present disclosure is shown in Figure27. A media pack 2702 is included that may be pleated and include nanofiber composite filter material as described in the present disclosure. The filtration product 2700 includes an upstream side 2704, and a downstream side 2706.

[0263] In some embodiments, the nanofiber composite filter material produced above can be used for air purification, cabin air filter, HVAC filtration, liquid filtration etc.

[0264] To better illustrate the method and apparatuses disclosed herein, a non-limiting list of embodiments is provided here:

[0265] Aspect 1. A composite filter media comprising a first nanofiber layer and second nanofiber layer, an inner support layer arranged between the first and second nanofiber layers, wherein the inner support layer provides support, separation and spacing for the first and second nanofiber layers and reduces the filling density of the nanofiber layers; the first nanofiber layer comprising nanofibers with a diameter of Inm to 5000nm, and the inner support layer having an average fiber diameter of less than 100 pm.

[0266] Aspect 2. The composite filter media of aspect 1, the first nanofiber layer comprising nanofibers with an average diameter of lOnm to 5000nm, and the inner support layer having an average fiber diameter of less than 30 pm.

[0267] Aspect 3. The composite filter media of aspect 1, wherein the inner support layer has a basis weight less than 80 grams per square meter and the inner support layer comprises of any of the following alone or in combination: spunbond nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven fabric and fiber mesh.

[0268] Aspect 4. The composite filter media of aspect 3, wherein the difference of particle filtration efficiency between the downstream nanofiber layer and the adjacent upstream nanofiber layer is less than 60%.

[0269] Aspect 5. The composite filter media of aspects 1 to 4 contains monocomponent nanofibers or multicomponent nanofibers, wherein the larger size fibers mixed with smaller size fibers. The large size fiber is in the range of 100-5000nm, preferably larger than 200nm, preferably larger than 300nm.; the small size fiber is in the range of 10-500nm, preferably less than 200nm, preferably less than 150nm. The mass ration of large size fiber to smaller size fiber is 10:90 to 99: 1.

[0270] Aspect 6. The composite filter media of aspects 1-4 , the large size fiber is in the range of 200-5000nm; the small size fiber is in the range of 10-200nm. The mass ration of large size fiber to smaller size fiber is 40:60 to 90: 10.

[0271] Aspect 7. The composite filter media of aspect 1, wherein the nanofiber layer comprises submicron fibers and micro fibers; and the average fiber diameter of the nanofiber layer has a single peak distribution within the average fiber diameter range of the nanofibers or the fiber diameter of the nanofiber layer has a double or multi peak distribution, and the first peak is within the diameter range of the nanofibers, and the other peaks are within the diameter range of the submicron or micro fibers.

[0272] Aspect 8. The composite filter media of aspect 1, further comprising a top outer support layer placed above the top nanofiber layer and / or a bottom outer support layer placed below the bottom layer of the bottom nanofiber layer, the outer support layer providing strength and / or stiffness for the composite filter media.

[0273] Aspect 9. The composite filter media of aspect 8, wherein the outer support layer placed below the bottom nanofiber layer is the first outer support layer and the outer support layer placed above the top nanofiber layer is the second outer support layer.

[0274] Aspect 10. The composite filter media of aspect 1, wherein the material of the nanofiber comprises any of the following polymer or inorganic material: PA6, PA56, PA66, PAI 010, PAN, PLA, PU, PVDF, PS, PEI, PMIA, A12O3, SiO2 and ZrO2, or any combination thereof.

[0275] Aspect 11. The composite filter media of aspect 1, wherein the nanofiber is continuous fibers and discontinuous fibers.

[0276] Aspect 12. The composite filter media of aspect 1, wherein the material of the inner support layer comprises of any one of the following: PP, PET, PE, PA, PVDF, PAN, PS, PET / PE, PET / LMPET, PLA, and glass fiber, and any combination thereof.

[0277] Aspect 13. The composite filter media of aspect 1, wherein when the inner support layer comprises bicomponent polymer, the weight ratio of polymer in the skin layer to polymer in the core layer is between 30 / 70 and 70 / 30; or 20 / 80 to 80 / 20; or 10 / 90 to 90 / 10.

[0278] Aspect 14. The composite filter media of aspect 1, wherein the average fiber diameter of the inner support layer (2) is between 0.3 p m~100 p m.

[0279] Aspect 15. The composite filter media of aspect 1, wherein the average fiber diameter of the inner support layer is between 0.5 -6pm.

[0280] Aspect 16. The composite filter media of aspect 1, wherein the average fiber diameter of the inner support layer is between 7-25 pm.

[0281] Aspect 17. The composite filter media of aspect 1, wherein the outer support layers (3) are selected from the group comprising spunbond nonwoven fabric, air laid nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven fabric, any combination thereof.

[0282] Aspect 18. The composite filter media of aspects 1 to 4, wherein the nanofiber layer also includes submicron fibers and micron fibers with a fiber diameter of 60 microns or less.

[0283] Aspect 19. The composite filter media of aspect 18, wherein submicron fibers and microfibers are uniformly distributed staple fibers and / or continuous filaments and are made of polymers or inorganic.

[0284] Aspect 20. The composite filter media of aspect 18, wherein the submicron and microfibers comprise any one of the following PA6, PA56, PA66, PAI 010, PAN, PLA, PU, PES, PBT, PC, PVDF, PI, PMIA, PTFE, A12O3, SiO2, ZrO2, PP, PE, PET, PET / PE PET / LMPET and glass fibers, or any combination thereof.

[0285] Aspect 21. The composite filter media of aspect 1, wherein in the nanofiber layer, the number ratio of the nanofiber to the micron fiber and / or the submicron fiber is 1 :6-600: 1 and the mass ratio is 1 :99-10: 1.

[0286] Aspect 22. A method for preparing a composite filter media comprising steps SI and S2 wherein: SI. The nanofiber layer (1) formed on the inner support layer (2) and the first outer support layer (31) by electrospinning. The nanofiber layer (1) includes nanofibers with a diameter of Inm to 5000 nm, and the inner support layer (2) can be any or combination of spunbond nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown or fiber mesh with a fiber diameter of less than 100pm; and S2. The optional second outer support (32) (can also function as a protection, dust loading or efficiency layer) is placed above the nanofiber layer (1) on theuppermost side. The nanofiber layer (1), the inner support layer (2) and the outer support layer (3) were compounded by hot pressing, glue bonding or ultrasonic compounding or the combined to obtain a composite filter media.

[0287] Aspect 23. A method for preparing a composite filter media comprising steps SI and S2 wherein: SI comprises forming a first nanofiber layer by electrospinning on an inner support layer and forming a second nanofiber layer by electrospinning on a first outer support layer wherein the first nanofiber layer, the inner support layer, the second nanofiber layer and the first outer support layer constitutes a composite filter media unit wherein the first and second nanofiber layers comprise nanofibers with a diameter of 1 nm to 5000 nm, and the inner support layer comprises spunbond nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric or fiber mesh with a fiber diameter of less than 100pm; and S2 comprises placing a second outer support or protection or dust loading layer above the first nanofiber layer wherein the first nanofiber layer, the inner support layer, and the outer support layer are combined by hot pressing, glue bonding, and / or ultrasonic compounding to obtain a composite filter media.

[0288] Aspect 24. The method of aspects 22 or 23, wherein in step SI, the number of the inner support layers (2) is at least one, and the thickness and basis weight of the inner support layers (2) can be different; the first outer support layer (31) can be any or any combination of the following: spunbond nonwoven fabric, dry laid nonwoven fabric, wet laid nonwoven fabric, meltblown nonwoven fabric or fiber mesh with basis weight less than 80gsm, and the optional second outer support layer (32).

[0289] Aspect 25. The method of aspects 22 or 23, wherein in step SI, the number of the inner support layers is at least two and the thickness and basis weight of the inner support layers can be different; and the first outer support layer and the optional second outer support layer comprise spunbond nonwoven fabric, dry laid nonwoven fabric, meltblown nonwoven fabric, or wet laid nonwoven fabric or fiber mesh.

[0290] Aspect 26. The method of aspects 22 or 23, in step SI, the nanofiber layer (1) was obtained by depositing nanofibers on the inner support layer (2) and the first outer support layer (31) through electrospinning, and the nanofiber diameter was less than or equal to 5 pm. The fiber diameter of theinner support layer (2) and the first outer support layer was 0.5 pm to 100 pm, and the number ratio of the nanofibers to the micro fibers and / or the submicron fibers was 1 :6 to 600: 1, and the mass ratio was 10:90 to 10: 1.

[0291] Aspect 27. The method of aspects 22 or 23, in step SI, the nanofiber layer (1) can also be obtained by depositing nanofibers, micro fibers and / or submicron fibers simultaneously on the inner support layer (2) and the first outer support layer (31) through electrospinning, and the nanofiber diameter was less than or equal to 5 pm, the fiber diameter of the submircon and micron fibers was less than or equal to 100pm. The fiber diameter of the inner support layer (2) was 0.5 pm to 100 pm. The number ratio of the nanofibers to the micro fibers and / or the submicron fibers was 2: 1 to 600: 1, and the mass ratio was 1 :99 to 10:1.

[0292] Aspect 28. The composite filter media of any one of the previous claims, wherein the nanofibers, micro fibers and / or submicron fibers can be created by electrospinning method or by the combination of electrospining and other fiber dispersion and web forming methods such as airlaid, drylaid, or aerodynamic web forming methods.

[0293] Aspect 29. The composite filter media of any one of the previous claims, wherein the nanofiber layers can be multiple layers of 2-99 layers, inner support layers can be 1-98 layers.

[0294] Aspect 30. The composite filter media of any one of the previous claims, wherein the nanofiber layers comprise mixed fibers of lofty structured nanofiber and finer nanofiber.

[0295] Aspect 31. The composite filter media of any one of the previous claims, wherein the nanofiber media can be combined together with activated carbon particles to form adsorbing composite filter media.

[0296] Aspect 32. A composite filter media comprising multi-component nanofibers wherein at least one of the nanofibers has lofty structure , mixed together with other fine nanofiber in one layer or build in a layer by layer structure.

[0297] Aspect 33. The composite filter media of aspect 32, wherein the lofty structure nanofibers have an average diameter of between 100 nm and 5 pm and wherein the fine nanofibers have an average diameters between 10 nm and 300nm.

[0298] Aspect 34. The composite filter media of aspect 33, wherein the lofty structure nanofibers have diameters greater than 0.1pm and preferably greater than .3 pm, and preferably greater than .5 pm, and wherein the fine nanofibers have diameters less than 0.3 pm, and preferably less than 0.15 pm.

[0299] Aspect 35. The composite filter media of aspect 34 wherein the lofty structured nanofibers have a loftiness (void volume) of more than 70%.

[0300] Aspect 36. The composite filter media of aspect 34, wherein the lofty structured nanofibers and fine nanofibers have a mass mixing ratio of a range from 10:90 to 99: 1.

[0301] Aspect 37. The composite filter media of any one of the previous claims, wherein the nanofiber layers can be multiple layers of 2-99 layers, inner support layers can be 1-98 layers.

[0302] Aspect 38. The composite filter media of any of the preceding aspects, wherein the filtration efficiency of multi-component nanofiber layer can be 30% ~ 99.9999995%.

[0303] Aspect 39. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtration efficiency is 60-85% and filtration flow resistance is 5-20Pa when tested according to ISO29463-3 or other equivalent standards.

[0304] Aspect 40. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtration efficiency is 85-95% and filtration resistance is 15-50 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0305] Aspect 41. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtration efficiency is 95-99.5% and filtration resistance is 30-150 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0306] Aspect 42. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtration efficiency is 99.5-99.95% and filtration resistance is 70-200 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0307] Aspect 43. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtrationefficiency is 99.95-99.995% and filtration resistance is 120-230 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0308] Aspect 44. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtration efficiency is 99.995-99.9995% and filtration resistance is 150-280Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0309] Aspect 45. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtration efficiency is 99.9995-99.99995% and air flow resistance is 180-320Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0310] Aspect 46. The composite filter media of any of the preceding aspects, having high efficiency and low flow resistance such that filtration efficiency is 99.99995-99.999995% and filtration resistance is 250-400 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0311] Aspect 47. A composite filter media comprising at least one support layer and at least one multi-component nanofiber layer wherein the multi component nanofiber layer includes lofty structured nanofibers and fine nanofibers.

[0312] Aspect 48. The filter of aspect 47, wherein the prepared nanofiber layers with the same or different filtration efficiency can be compounded by hot pressing, glue bonding, and / or ultrasonic compounding to meet specific use needs.

[0313] Aspect 49. The composite filter media of aspect 47, wherein the lofty structured nanofibers and the fine nanofiber are prepared by needle electrospinning or needleless electrospinning technology or centrifugal force spinning.

[0314] Aspect 50. The composite filter media of aspect 47, wherein there are 1-10 nanofiber layers and 2-11 support layers.

[0315] Aspect 51. The composite filter media composite filter media of aspect 47, having at least one outside support layer.

[0316] Aspect 52. The composite filter media of aspect 47, wherein there are 2-10 nanofiber layers and 1-9 inner support layers.

[0317] Aspect 53. The composite filter media of aspect 47, wherein the nanofiber layer can be made of a polymer, such as PA, PVDF, PI, PAN, PES,TPU, PEI, PES, PS, PMIA, etc., or inorganic materials, such as A12O3, SiO2, ZrO2, etc. and the nanofibers are continuous filaments or staple fibers.

[0318] Aspect 54. The composite filter media of aspect 47, wherein the at least one support layer is made of PET spunbond or wet laid nonowoven fabric or dry laid nonowoven fabric.

[0319] Aspect 55. The composite filter media of any of the preceding aspects, wherein the filtration efficiency of the composite filter media can be 30% ~ 99.9999995%.

[0320] Aspect 56. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 60-85% and filtration flow resistance is 5-20Pa when tested according to ISO29463-3 or other equivalent standards.

[0321] Aspect 57. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 85-95% and filtration resistance is 15-50 Pa at 5.33cm / s when tested according to ISO29463- 3 or other equivalent standards.

[0322] Aspect 58. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 85-95% and filtration resistance is 15-50 Pa at 5.33cm / s when tested according to ISO29463- 3 or other equivalent standards.

[0323] Aspect 59. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 95-99.5% and filtration resistance is 30-150 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0324] Aspect 60. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.5-99.95% and filtration resistance is 70-200 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0325] Aspect 61. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.95- 99.995% and filtration resistance is 120-230 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0326] Aspect 62. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.995-99.9995% and filtration resistance is 150-280Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0327] Aspect 63. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.9995- 99.99995% and filtration resistance is 180-320Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0328] Aspect 64. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.99995- 99.999995% and filtration resistance is 250-400 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0329] Aspect 65. A method of preparing multi-component nanofiber composite filter media comprising the following steps: 1 ) A first polymer or polymers is added to a solvent, and is stirred until fully dissolved to obtain the polymer solution A with a mass concentration of between 10%- 50%; 2) A second polymer or polymers is added to a solvent, and is stirred until fully dissolved to obtain the polymer solution B with a mass concentration of between 3%-30%; 3) Two or more polymer solutions are prepared and feed into two or more electrospinning devices, and spun into two or more sized nanofibers. The two or more size nanofibers were combined to form multicomponent nanofiber structure online. The mass ratio of large diameter nanofiber to fine nanofibers is between 10:90 and 99: 1. The multicomponent nanofibers are deposit on a support layer to form composite filter media comprising multicomponent nanofibers.

[0330] Aspect 66. The method of aspect 65, wherein the minimum fiber diameter of fine nanofibers is between 10-100nm, and the maximum fiber diameter of fine nanofibers is between 200-300 nm, and the average fiber diameter of fine nanofibers is between 30-150 nm; and the minimum diameter of large diameter nanofibers is between 200-300nm, the maximum fiber diameter of large diameter nanofibers is between 1000-5000nm, and the average fiber diameter of large diameter nanofibersis between 300-3000nm, and the loftiness (void volume) of the multi-component nanofiber composite filter media is between 70-99%.

[0331] Aspect 67. The method of aspect 65, wherein at the flow rate of 5.33 cm / s with 0.3 p m NaCl polydisperse aerosol, and an efficiency of60%~99.9999999%, the pressure drop of multi-component nanofibers composite filter media is 5~500pa.

[0332] Aspect 68. The method of aspect 65, wherein at the flow rate of 5.33 cm / s with 0.3 p m NaCl polydisperse aerosol, and an efficiency of at least 60%, the pressure drop of multi-component nanofibers composite filter media is no more than 500pa.

[0333] Aspect 69. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 60-85% and filtration flow resistance is 5-20Pa when tested according to ISO29463-3 or other equivalent standards.

[0334] Aspect 70. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 85-95% and filtration resistance is 15-50 Pa at 5.33cm / s when tested according to ISO29463- 3 or other equivalent standards.

[0335] Aspect 71. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 85-95% and filtration resistance is 15-50 Pa at 5.33cm / s when tested according to ISO29463- 3 or other equivalent standards.

[0336] Aspect 72. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 95-99.5% and filtration resistance is 30-150 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0337] Aspect 73. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.5-99.95% and filtration resistance is 70-200 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0338] Aspect 74. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.95- 99.995% and filtration resistance is 120-230 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0339] Aspect 75. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.995- 99.9995% and filtration resistance is 150-280Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0340] Aspect 76. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.9995- 99.99995% and filtration resistance is 180-320Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0341] Aspect 77. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.99995- 99.999995% and filtration resistance is 250-400 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0342] Aspect 78. The method of aspect 65, wherein the polymer is selected from the group including polyurethane, Polystyrene, Polyimide, Polyethylene glycol terephthalate, Polybutylene terephthalate, Nylon (Nylon-6, Nylon-66, Nylon-56, Nylon-1010) , Polyacrylonitrile, Polyvinylidene difluoride, Poly-Vinyl Fluoride, Polytetrafluoroethylene, Chlorotrifluoroethylene, Polyethylene oxide, Polymethyl methacrylate, Poly (m- phenyleneisophthalamide) , Polysulfone, Polyphenylene sulfone resins, Polyethersulfone, Polyphenylene sulfide, Polyetherimide, Polylactic acid, Poly-1- lactide, Poly-d-lactide, Polycaprolactone, Polyvinyl alcohol, polyvinyl pyrrolidone, Acrylic resin, Cellulose acetate, Chitosan, Silk fibroin and copolymers or homopolymers of the above polymers, and any combination thereof.

[0343] Aspect 79. The method of aspect 65, wherein the solvent is selected from the group including Water, Ethanol, benzyl alcohol, Formic acid, Acetic Acid, Acetone, Methyl-ethyl ketone, N,N-Dimethylformamide, N,N- dimethylacetamide, Dimethyl sulfoxide, N-Methylpyrrolidone, Dichloromethane, Trichloromethane, Hexafluoroisopropanol, Tetrahydrofuran, Trifluoroacetic acid, Tetrafluoroethene, and any combination thereof.

[0344] Aspect 80. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 60- 99.9999995% and filtration resistance is 5-500 Pa when tested according to ISO29463-3 or other equivalent standards.

[0345] Aspect 81. The composite filter media of aspect 47, having high efficiency and low resistance such that filtration efficiency is at least 60% and filtration resistance is less than 500 Pa when tested according to ISO29463-3 or other equivalent standards.

[0346] Aspect 82. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 60-85% and filtration flow resistance is 5-20Pa when tested according to ISO29463-3 or other equivalent standards.

[0347] Aspect 83. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 85-95% and filtration resistance is 15-50 Pa at 5.33cm / s when tested according to ISO29463- 3 or other equivalent standards.

[0348] Aspect 84. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 95-99.5% and filtration resistance is 30-150 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0349] Aspect 85. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.5-99.95% and filtration resistance is 70-200 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0350] Aspect 86. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.95- 99.995% and filtration resistance is 120-230 Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0351] Aspect 87. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.995- 99.9995% and filtration resistance is 150-280Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0352] Aspect 88. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.9995- 99.99995% and filtration resistance is 180-320Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards.

[0353] Aspect 89. The composite filter media of aspect 47, having high efficiency and low flow resistance such that filtration efficiency is 99.99995- 99.999995% and filtration resistance is 250-400Pa at 5.33cm / s when tested according to ISO29463-3 or other equivalent standards. 90. The composite filter media of any one of the preceding aspects, wherein the filter mediea is combinedtogether with activated carbon particles to form adsorbing composite filter media.

[0354] Aspect 91. A composite filter media, comprising: a support layer; an electrospun nanofiber layer; an adsorption layer comprising activated carbon; and a larger pore size fibrous material layer.

[0355] Aspect 92. The composite filter media of aspect 91, having a protective layer disposed on the adsorbing layer such that the adsorbing layer is an inner layer of composite filter the media.

[0356] Aspect 93. The composite filter media of aspect 91, wherein the larger pore size fibrous material layer is selected from a group comprising of meltblown, electrostatic media, spunbond, wet laid fabric, dry laid fabric, triboelectric media, and any combination thereof.

[0357] Aspect 94. The composite filter media of aspect 91, wherein the nanofiber material is selected from a group comprising TPU, PVDF, nylon, PES, PLA, PAN, PEI, PS,CA and any combination thereof.

[0358] Aspect 95. The composite filter media of aspect 91, wherein the activated carbon material comprises material selected from the group comprising of activated carbon, activated carbon with glue powder, other adsorbent materials.

[0359] Aspect 96. The composite filter media of aspect 91, wherein the support layer has significant filtration efficiency.

[0360] Aspect 97. The composite filter media of aspect 91, wherein the support layer has significant dust loading capacity.

[0361] Aspect 98. The composite filter media of aspect 91, wherein adjacent layers are bonded together by a bond selected from the group comprising ultrasonic bonds, hot melt glue spray bonds, glue powder with heat lamination bonds, membrane transferred glue lamination bonds, and any combination thereof.

[0362] Aspect 99. The composite filter media of aspect 91, wherein the support layer comprises a thermoplastic polymer resin.

[0363] Aspect 100. The composite filter media of aspect 91, wherein each of at least two layers comprises an antimicrobial.

[0364] Aspect 101. The composite filter media of aspect 91, wherein the nanofibers layer are selected from the group consisting of electrospun needlespinning nanofibers, electrospun needleless spinning nanofibers, centrifugal force spinning nanofibers, and any combination thereof.

[0365] Aspect 102. The composite filter media of aspect 91, having certain concentration (1-10% ) of Vitamin C added through electrospinning, electrostatic spraying, dip coating, spray coating, and any combination thereof.

[0366] Aspect 103. The composite filter media of aspect 91, wherein the fibers of the electrospun nanofiber layer have a concentration of 10 to 50% wt% of Vitamin C.

[0367] Aspect 104. The composite filter media of aspect 91, wherein the nanofibers of the nanofiber layer have an average diameter less than 5 pm.

[0368] Aspect 105. The composite filter media of aspect 91, wherein the nanofibers of the nanofiber layer have an average diameter less than 1 m.

[0369] Aspect 106. The composite filter media of aspect 91, wherein the nanofibers have an average diameter less than 0.5 pm.

[0370] Aspect 107. The composite filter media of aspect 91, having a resistance of 3-100 pa, an efficiency of 25-99.999% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0371] Aspect 108. The media of aspect 91, wherein the composite filter media has an air flow resistance of 2-10 Pa and an efficiency of 20-85% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0372] Aspect 109. The media of aspect 91 wherein the composite filter media has an air flow resistance of 10-30 Pa and an efficiency of 75-95% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0373] Aspect 110. The media of aspect 91, wherein the composite filter media has an air flow resistance of 30-50 Pa and an efficiency of 90-99.9% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0374] Aspect 111. The media of aspect 91, wherein the composite filter media has an air flow resistance of 50-70Pa and an efficiency of 99-99.95% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0375] Aspect 112. The media of aspect 91, wherein the composite filter media has an air flow resistance of 70-100Pa and an efficiency of 99.5-99.999% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0376] Aspect 113. The composite filter media of aspect 91, wherein the support layer comprises of PET, the nanofiber layer comprises of fibersconsisting of PVDF, PAN, PEI, PS, Nylon, PLA, PES, TPU, PLA, CA and any combination thereof , the adsorbing layer comprising activated carbon or other adsorbing materials, and the top layer comprising needle-punched triboelectric media.

[0377] Aspect 114. The composite filter media of aspect 113, wherein the needle-punched triboelectric media has a basis weight of 30-100gsm, a thickness of 0.3-1.2mm, an air flow resistance of 3-30 Pa at a flow rate of 16.7 cm / s, and a filtration efficiency of 25-95% with a flow rate of 26.25cm / s.

[0378] Aspect 115. The composite filter media of aspect 91, having a PET dry-laid nonwoven support layer with a basis weight of 40-100 gsm, a thickness of 0.25-0.5 mm, a tensile strength of 100-250 N / 5cm (MD) and of 30- 90 N / 5cm (CD).

[0379] Aspect 116. The composite filter media of aspect 91, having an electrospun nanofiber with a diameter of about 0.03-5um, an air flow resistance of 3-100Pa and a filtration efficiency of 25-99.9999% with 0.3mm NaCl at flow rate of 5.33cm / s and disposed onto PET nonwoven substrate by electrostatic spinning method.

[0380] Aspect 117. The media of aspect 91, wherein the composite filter media has an air flow resistance of 2-10 Pa and an efficiency of 20-85% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0381] Aspect 118. The media of aspect 91, wherein the composite filter media has an air flow resistance of 10-30 Pa and an efficiency of 75-95% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0382] Aspect 119. The media of aspect 91, wherein the composite filter media has an air flow resistance of 30-50 Pa and an efficiency of 90-99.9% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0383] Aspect 120. The media of aspect 91, wherein the composite filter media has an air flow resistance of 50-70Pa and an efficiency of 99-99.95% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0384] Aspect 121. The media of aspect 91, wherein the composite filter media has an air flow resistance of 70-100Pa and an efficiency of 99.5-99.999% with 0.3mm NaCl at flow rate of 5.33cm / s.

[0385] Aspect 122. The media of claim any one of the preceding aspects, wherein the needle-punched triboelectric media has a basis weight of 10- 200gsm, a thickness of 0.3-1.2 mm, an air resistance of 2.5-10 Pa at a flow rate of 5.33 cm / s, and a filtration efficiency of 25-95% with 0.3mm NaCl at a flow rate of 5-50 cm / s.

[0386] Aspect 123. The composite filter media of aspect 91, having a support layer fabric comprising PET or PP, the nanofiber layer comprising any of PVDF, PA, TPU, PES, PAN, PEI, PS, PLA, CA and any combination thereof, the adsorbing layer comprising activated carbon, and the top layer comprising melt-blown fabric.

[0387] Aspect 124. The composite filter media of aspect 91, having a support layer of PET or PP nonwoven substrate, the nanofiber layer comprising electrospun nanofiber, the adsorbing layer comprising activated carbon, and the top layer comprising melt-blown fabric or trioelectric charged media, or other electrostatic charged media.

[0388] Aspect 125. A process for creating a nanofiber containing composite material including: a. nanofiber polymer material, solvents, and optional additives are combined to make a nanofiber solution; b. the nanofiber solution is electrospun onto a support layer creating a nanofiber layer, the electrospinning step includes a flow rate of .001-1.0 ml / min / needle, a voltage of 15- 70kv, DCD 10-30cm, controlled temperature and humidity; c. adsorbing material is sprayed on the nanofiber layer or other layer adjacent to the nanofiber layer; d. applying a top layer on the adsorbing layer, the top layer being of a material selected from the group comprising meltblown material, triboelectric media, dry laid fabric, wet laid fabric, spunbond, and any combination thereof.

[0389] Aspect 126. The process of aspect 125, wherein the nanofiber layer can comprise multi-layered nanofiber structure wherein nanofiber layers and inner support layers are alternatively placed to improve efficiency and lower the pressure drop as well as improve the dust loading capacity of the media.

[0390] Aspect 127. The process of aspect 125, wherein the nanofiber layer can comprise mult-component nanofibers wherein the coarse and lofty structure nanofiber combined with fine nanofiber to further improve efficiency and lower the pressure drop as well as improve the dust loading capacity of the media.

[0391] Aspect 128. The process of aspect 125, wherein the nanofiber layer can also include submicron fibers and micron fibers with a fiber diameter of 60 microns or less.

[0392] Aspect 129. The process of aspect 125, wherein submicron fibers and microfibers are staple fibers and / or continuous filaments and are made of polymers or inorganic.

[0393] Aspect 130. The process of aspect 125, wherein the submicron and microfibers comprise any one of or combination of the following PA6, PA56, PA66, PAI 010, PAN, PLA, PU, PVDF, CA, PEI, PS, PES PMIA, PTFE, A12O3, SiO2, ZrO2, PP, PE, PET, PET / PE PET / LMPET and glass fibers.

[0394] Aspect 131. The process of aspect 125, wherein the number ratio of the nanofiber to the micron fiber and / or the submicron fiber is 1 :6~600: 1 and the mass ratio is 1 :99-10: 1.

[0395] Aspect 132. The process of aspect 125, wherein the nanofiber layer (1) is obtained by depositing nanofibers, micro fibers and / or submicron fibers simultaneously on the inner support layer (2) and the first outer support layer (31) through electrospinning, and the nanofiber diameter was less than or equal to 5 pm, the fiber diameter of the submicron and micron fibers was less than or equal to 100pm. The fiber diameter of the inner support layer (2) was 0.5 pm to 100 pm. The number ratio of the nanofibers to the micro fibers and / or the submicron fibers was 1 :2 to 600: 1, and the mass ratio was 1 :99 to 10: 1.

[0396] Aspect 133. The media of aspect 91, wherein the nanofiber layer disposed onto the nonwoven substrate layer comprises electrospun nanofiber with a diameter of between .01-3 um, and has an air flow resistance of 1-15 Pa and a filtration efficiency of 20-99.95% at a flow rate of between 1.8- 26.7 cm / s; and the activated carbon comprises particles with a range of 10-150 mesh, an iodine value of between 100-4000, hardness of around 98, and ash content of 1- 20%.

[0397] Aspect 134. The composite filter media of aspect 91, wherein the support layer comprises PET, the nanofiber layer comprises PVDF, PA, PES, PAN,TPU, PS, PEI, PLA,CA and the larger pore size fibrous material layer comprises melt-blown or triboelectric charged fabric or electrostatic charged spunbond or electrostatic charged drylaid fabric.

[0398] Aspect 135. A composite filter media, comprising: a first distribution of nanofibers; a second distribution of fibers in contact with the first distribution of nanofibers; wherein the first distribution of nanofibers have a first peak diameter distribution less than 150 nm; and wherein the second distribution of fibers have a second peak diameter distribution larger than the first peak diameter distribution wherein the composite filter media has a void volume of greater than 70%.

[0399] Aspect 136. The composite filter media of aspect 135, wherein the second peak diameter distribution is between 0.3 and 25pm.

[0400] Aspect 137. The composite filter media of aspect 135, wherein the second distribution of fibers includes a second peak diameter distribution of 300-1000nm and wherein a mass ratio of the first distribution of nanofibers to the second distribution of fibers is between 10:90 and 70:30.

[0401] Aspect 138. The composite filter media of aspect 135, wherein the second distribution of fibers includes a second peak diameter distribution of 1.0 - 2.0pm and wherein a mass ratio of the first distribution of nanofibers to the second distribution of fibers is between 10:90 and 60:40.

[0402] Aspect 139. The composite filter media of aspect 135, wherein the second distribution of fibers includes a second peak diameter distribution of 1.5 - 3.0pm and wherein a mass ratio of the first distribution of nanofibers to the second distribution of fibers is between 10:90 and 60:40.

[0403] Aspect 140. The composite filter media of any one of aspects 135-139, wherein the composite filter media has a filtration efficiency no less than 90% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 40 Pa.

[0404] Aspect 141. The composite filter media of any one of aspects 135-139, wherein the composite filter media has a filtration efficiency no less than 99.5% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 150 Pa.

[0405] Aspect 142. The composite filter media of any one of aspects 135-139, wherein the composite filter media has a filtration efficiency no less than 99.95% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 180 Pa.

[0406] Aspect 143. The composite filter media of any one of aspects 135-139, wherein the composite filter media has a filtration efficiency no less than 99.995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 230 Pa.

[0407] Aspect 144. The composite filter media of any one of aspects 135-139, wherein the composite filter media has a filtration efficiency no less than 99.9995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 270 Pa.

[0408] Aspect 145. The composite filter media of any one of aspects 135-139, wherein the composite filter media has a filtration efficiency no less than 99.99995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 320 Pa.

[0409] Aspect 146. The composite filter media of any one of aspects 135-139, wherein the composite filter media has a filtration efficiency no less than 99.999995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 370 Pa.

[0410] Aspect 147. The composite filter media of any one of aspects 135-139, wherein the layers comprising nanofiber has a void volume of 85-95%.

[0411] Aspect 148. The composite filter media of any one of aspects 135-139, wherein the first distribution of nanofibers and the second distribution of fibers are layered on a support layer.

[0412] Aspect 149. The composite filter media of aspect 135, wherein the support layer includes bicomponent spunbond fibers with a PE skin layer and a PET core layer.

[0413] Aspect 150. A composite filter media, comprising: a plurality of layers, including; a nanofiber layer, wherein the nanofiber layer include a first fiber distribution having an average fiber diameter between 10 nm and 200 nm; a support layer, wherein the support layer includes a second fiber distribution having an average fiber diameter of 0.3-25pm; and wherein within the plurality of layers, a support layer is included between at least two nanofiber layers.

[0414] Aspect 151. The composite filter media of claim any one of the preceding aspects, wherein the support layer includes a spunbonded or meltblown or needle punched fiber structure.

[0415] Aspect 152. The composite filter media of any one of the preceding aspects, wherein a basis weight of a nanofiber layer and an adjacent support layer is between 8-35 g / m2.

[0416] Aspect 153. The composite filter media of aspect 135, wherein the nanofiber layer includes PVDF, PAN, PES, PA, TPU, PS, CA or PEI fibers.

[0417] Aspect 154. The composite filter media of any one of the preceding aspects, wherein the nanofiber layer further includes a third fiber distribution mixed with the first fiber distribution, the third fiber distribution having an average fiber diameter between 300-3000nm.

[0418] Aspect 155. The composite filter media of any one of the preceding aspects, further including an outer protection layer, the outer protection layer including fibers with an electric charge.

[0419] Aspect 156. The composite filter media of any one of the preceding aspects, further including a layer including activated carbon.

[0420] Aspect 157. The composite filter media of any one of any one of the preceding aspects, wherein the composite filter media has a filtration efficiency no less than 90% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 40 Pa.

[0421] Aspect 158. The composite filter media of any one of any one of the preceding aspects, wherein the composite filter media has a filtration efficiency no less than 99.5% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 150 Pa.

[0422] Aspect 159. The composite filter media of any one of any one of the preceding aspects, wherein the composite filter media has a filtration efficiency no less than 99.95% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 180 Pa.

[0423] Aspect 160. The composite filter media of any one of any one of the preceding aspects, wherein the composite filter media has a filtration efficiency no less than 99.995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 230 Pa.

[0424] Aspect 161. The composite filter media of any one of any one of the preceding aspects, wherein the composite filter media has a filtration efficiency no less than 99.9995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 270 Pa.

[0425] Aspect 162. The composite filter media of any one of any one of the preceding aspects, wherein the composite filter media has a filtration efficiency no less than 99.99995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 320 Pa.

[0426] Aspect 163. The composite filter media of any one of any one of the preceding aspects, wherein the composite filter media has a filtration efficiency no less than 99.999995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 370 Pa.

[0427] Aspect 164. The composite filter media from any of the previous claims, wherein the multicomponent nanofiber layer comprising large and small electrospun nanofibers, wherein the number ratio of small electrospun nanofibers to large electrospun nanofibers ratio is 10: 1-1000: 1, preferably 30: 1-300: 1, more preferably 80: 1-200: 1; the mass ratio is 10:90-90: 10, preferably 30:70-70:30; the average fiber diameter ratio 1 :3 - 1 : 100, preferably 1 :5-1 :30.

[0428] Aspect 165. The composite filter media from any of the previous claims, wherein the multicomponent nanofiber layer comprising electrospun nanofiber and staple fiber, the number ratio of electrospun nanofiber to large staple fiber ratio is 10: 1-1000: 1, preferably 50: 1-300: 1, more preferably 80: 1-200: 1; the mass ratio is 1 :300-10: 1, preferably 1 : 100-60:40; the average fiber diameter ratio is 1 : 10 - 1 : 1000, preferably 1 : 10- 1 :200;

[0429] Aspect 166. The composite filter media from any of the previous claims, wherein the inner support layer comprising meltblown: the average fiber diameter of the meltblown is 0.5-7 pm, preferably 1-5 pm, the basis weight is 5- 50 g / m2, preferably 8-20 g / m2.

[0430] Aspect 167. The composite filter media from any of the previous claims, wherein the inner support layer comprising spunbond: the average fiber diameter of the spunbond is 6-30 pm, preferably 10-20 pm, more preferably 12- 16 pm, the mass 5-50 g / m2, preferably 8-20 g / m2

[0431] Aspect 168. The composite filter media from any of the previous claims, wherein the 1st outer support layer provides the strength and stiffness to the composite filter media, the basis weight is 20-150g / m2, preferably 40- 130g / m2, the 2nd outer support layer for protection and / or dust loading: the basis weight is 10-150g / m2, preferably 15-100g / m2.

[0432] Aspect 169. A composite filter media, comprising: a first distribution of nanofibers; a second distribution of fibers in contact with the first distribution of nanofibers; wherein the first distribution of nanofibers has a first diameter distribution with a peak value that is less than 150 nm; and wherein the second distribution of fibers have a second diameter distribution with a peak value that is larger than the first peak value wherein the composite filter media has a void volume of greater than 70%.

[0433] Aspect 170. The composite filter media of aspect 169, wherein the second peak value is between 0.3 and 25pm.

[0434] Aspect 171. The composite filter media of aspect 169, wherein the second distribution of fibers includes a second peak value of 300-1000nm and wherein a mass ratio of the first distribution of nanofibers to the second distribution of fibers is between 10:90 and 70:30.

[0435] Aspect 172. The composite filter media of aspect 169, wherein the second distribution of fibers includes a second diameter distribution with a peak value of 1.0 - 3.0pm and wherein a mass ratio of the first distribution of nanofibers to the second distribution of fibers is between 10:90 and 60:40.

[0436] Aspect 173. The composite filter media of any one of the preceding aspects, wherein the layer comprising nanofiber has a void volume of 85-95%.

[0437] Aspect 174. The composite filter media of any one of the preceding aspects, wherein the first distribution of nanofibers and the second distribution of fibers are layered on a support layer.

[0438] Aspect 175. The composite filter media of aspect 174, wherein the support layer includes bicomponent spunbond fibers with a PE skin layer and a PET core layer.

[0439] Aspect 176. A composite filter media, comprising: a plurality of layers, including; a nanofiber layer, wherein the nanofiber layer includes a first fiber diameter distribution with a peak value that is between 10 nm and 200 nm; a support layer, wherein the support layer includes a second fiber diameter distribution with a peak value that is between 0.3-25pm; and wherein within the plurality of layers, a support layer is included between at least two nanofiber layers.

[0440] Aspect 177. The composite filter media of aspect 176, wherein the support layer includes a spunbonded or meltblown or needle punched fiber structure.

[0441] Aspect 178. The composite filter media of aspect 176, wherein a basis weight of a nanofiber layer and an adjacent support layer is between 8-35 g / m2.

[0442] Aspect 179. The composite filter media of aspect 176, wherein the nanofiber layer includes PVDF, PAN, PES, PA, TPU, or PEI fibers.

[0443] Aspect 180. The composite filter media of aspect 176, wherein the nanofiber layer further includes a third fiber diameter distribution mixed with the first fiber distribution, the third fiber diameter distribution having a peak value that is between 300-1000nm.

[0444] Aspect 181. The composite filter media of aspect 176, further including an outer protection layer, the outer protection layer including fibers with an electric charge.

[0445] Aspect 182. The composite filter media of aspect 176, further including a layer including activated carbon.

[0446] Aspect 183. The composite filter media ofany one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 70% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 20 Pa.

[0447] Aspect 184. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 90% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 40 Pa.

[0448] Aspect 185. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 99% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 120 Pa.

[0449] Aspect 186. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 99.5% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 150 Pa.

[0450] Aspect 187. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 99.95% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 180 Pa.

[0451] Aspect 188. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 99.995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 230 Pa.

[0452] Aspect 189. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 99.9995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 270 Pa.

[0453] Aspect 190. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 99.99995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 320 Pa.

[0454] Aspect 191. The composite filter media of any one of aspects 169-182, wherein the composite filter media has a filtration efficiency no less than 99.999995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 370 Pa

[0455] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more Aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can becombined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

[0456] Although an overview of the inventive subject matter has been described with reference to specific example embodiments, various modifications and changes may be made to these embodiments without departing from the broader scope of embodiments of the present disclosure. Such embodiments of the inventive subject matter may be referred to herein, individually or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single disclosure or inventive concept if more than one is, in fact, disclosed.

[0457] The embodiments illustrated herein are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed. Other embodiments may be used and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. The Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

[0458] As used herein, the term “or” may be construed in either an inclusive or exclusive sense. Moreover, plural instances may be provided for resources, operations, or structures described herein as a single instance. Additionally, boundaries between various resources, operations, modules, engines, and data stores are somewhat arbitrary, and particular operations are illustrated in a context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within a scope of various embodiments of the present disclosure. In general, structures and functionality presented as separate resources in the example configurations may be implemented as a combined structure or resource. Similarly, structures and functionality presented as a single resource may be implemented as separate resources. These and other variations, modifications, additions, and improvements fall within a scope of embodiments of the present disclosure as represented by the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

[0459] The foregoing description, for the purpose of explanation, has been described with reference to specific example embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the possible example embodiments to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The example embodiments were chosen and described in order to best explain the principles involved and their practical applications, to thereby enable others skilled in the art to best utilize the various example embodiments with various modifications as are suited to the particular use contemplated.

[0460] It will also be understood that, although the terms “first,” “second,” and so forth may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first contact could be termed a second contact, and, similarly, a second contact could be termed a first contact, without departing from the scope of the present example embodiments. The first contact and the second contact are both contacts, but they are not the same contact.

[0461] The terminology used in the description of the example embodiments herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used in the description of the example embodiments and the appended examples, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0462] As used herein, the term “if’ may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upondetermining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.

Claims

Claims1. A composite filter media, comprising: a first distribution of nanofibers; a second distribution of fibers in contact with the first distribution of nanofibers; wherein the first distribution of nanofibers has a first diameter distribution with a peak value that is less than 150 nm; and wherein the second distribution of fibers have a second diameter distribution with a peak value that is larger than the first peak value wherein the composite filter media has a void volume of greater than 70%.

2. The composite filter media of claim 1, wherein the second peak value is between 0.3 and 25pm.

3. The composite filter media of claim 1, wherein the second distribution of fibers includes a second peak value of 300-1000nm and wherein a mass ratio of the first distribution of nanofibers to the second distribution of fibers is between 10:90 and 70:30.

4. The composite filter media of claim 1, wherein the second distribution of fibers includes a second diameter distribution with a peak value of 1.0 - 3.0pm and wherein a mass ratio of the first distribution of nanofibers to the second distribution of fibers is between 10:90 and 60:40.

5. The composite filter media of any one of the preceding claims, wherein the layer comprising nanofiber has a void volume of 85-95%.

6. The composite filter media of any one of the preceding claims, wherein the first distribution of nanofibers and the second distribution of fibers are layered on a support layer.

7. The composite filter media of claim 6, wherein the support layer includes bicomponent spunbond fibers with a PE skin layer and a PET core layer.

8. A composite filter media, comprising: a plurality of layers, including; a nanofiber layer, wherein the nanofiber layer includes a first fiber diameter distribution with a peak value that is between 10 nm and 200 nm; a support layer, wherein the support layer includes a second fiber diameter distribution with a peak value that is between 0.3-25pm; and wherein within the plurality of layers, a support layer is included between at least two nanofiber layers.

9. The composite filter media of claim 8, wherein the support layer includes a spunbonded or meltblown or needle punched fiber structure.

10. The composite filter media of claim 8, wherein a basis weight of a nanofiber layer and an adjacent support layer is between 8-35 g / m2.

11. The composite filter media of claim 8, wherein the nanofiber layer includes PVDF, PAN, PES, PA, TPU, or PEI fibers.

12. The composite filter media of claim 8, wherein the nanofiber layer further includes a third fiber diameter distribution mixed with the first fiber distribution, the third fiber diameter distribution having a peak value that is between 300-1000nm.

13. The composite filter media of claim 8, further including an outer protection layer, the outer protection layer including fibers with an electric charge.

14. The composite filter media of claim 11, further including a layer including activated carbon.

15. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 70% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 20 Pa.

16. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 90% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 40 Pa.

17. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 99% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 120 Pa.

18. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 99.5% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 150 Pa.

19. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 99.95% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 180 Pa.

20. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 99.995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 230 Pa.

21. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 99.9995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 270 Pa.

22. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 99.99995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow nomore than 320 Pa.

23. The composite filter media of any one of claims 1-14, wherein the composite filter media has a filtration efficiency no less than 99.999995% for 0.3mm NaCl particles at a flow rate of 5.33 cm / s and a resistance to air flow no more than 370 Pa.

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