Composite filtration media and methods

Abstract

A composite filtration medium can include a first nanofiber distribution layer, and can further include a second fiber distribution layer in contact with the first nanofiber distribution layer, wherein the first nanofiber distribution layer has a fiber diameter distribution peak less than 150 nm, the second fiber distribution layer has a fiber diameter distribution peak greater than the first peak, and the composite filtration medium has a porosity greater than 70%.

Description

[Technical Field]

[0001] This patent application claims the benefit of priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 63 / 445,292, entitled "High Performance Filter Media," filed February 13, 2023, which is incorporated by reference in its entirety into this application.

[0002] This patent application claims the benefit of priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 63 / 445,293, entitled "Composite Filter Media and Method of Manufacturing the Same," filed February 13, 2023, which is incorporated herein by reference 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 No. 63 / 445,294, entitled "Multicomponent Nanofiber Composite Structure Filter Media," filed February 13, 2023, which is incorporated by reference in its entirety into this application.

[0004] The present invention relates to a composite filtration medium and a method for preparing the same. [Background technology]

[0005] With the progress of industrialization and urbanization, large amounts of toxic and harmful substances released into the natural environment by industrial production and human activities have far exceeded the Earth's self-purification capacity, causing serious environmental problems. Air pollution, which directly affects humans, not only pollutes the atmosphere and causes frequent hazy weather worldwide, but also seriously affects the quality of human life and threatens human life and health. For example, fine pollutants in the air inhaled by the human body directly enter the bronchi, alveoli, and blood, causing asthma, bronchitis, cardiovascular disease, pneumoconiosis, lung cancer, and other diseases, causing irreversible and serious harm to human health. Therefore, effectively reducing the impact of air pollution on people has become a global priority.

[0006] To date, humans have developed various methods and technological means to remove particulate matter from the atmosphere. Among these, physical filtration using fiber media is considered to be the most effective, reliable, and cost-effective method. Among the many fiber composite filtration media, nanofiber composite filtration media have advantages such as a large specific surface area and high separation efficiency. Furthermore, when fiber diameters reach the nanometer order, airflow can slide over individual fibers, significantly reducing the flow resistance of the composite filtration media. Therefore, nanofiber composite filtration media is considered to have excellent prospects for application in the field of air filtration. However, nanofiber composite filtration media also has inherent drawbacks, such as short nanofiber spacing (i.e., a dense stack structure) and a high fiber packing density. Therefore, nanofiber composite filtration media, especially in the high-filtration efficiency range, has characteristics such as high flow resistance and low dust retention capacity. This significantly limits the broader use of nanofiber composite filtration media.

[0007] The invention patent, patent number CN106984201B, discloses a composite air filtration membrane with high efficiency, low flow resistance, and high dust retention capacity. This composite filtration medium has a nano-spider web layer, a bead fiber layer, and a nano-spider web coating layer arranged from bottom to top to form a filtration gradient and increase dust retention capacity. However, the electrospun nano-fiber layer with nano-spider web and bead structure has poor process stability and the adjustment efficiency of the spider web coverage and bead structure remains low, leaving many challenges to be overcome before it can be widely used.

[0008] Patent number CN201480041084.1 discloses a nanofiber composite filtration medium with high dust retention capacity. The ratio of the geometric mean diameter of the fibers in the upstream nanofiber composite filtration medium to the geometric mean diameter of the fibers in the downstream nanofiber composite filtration medium is 1.2 to 2.8. This method allows the nanofiber composite filtration medium to form a consistent filtration gradient and achieve high dust retention capacity. However, the internal structure of this nanofiber composite filtration medium remains dense, which does not effectively resolve the issue of nanofiber packing density, limiting the improvement of filtration performance. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Chinese Patent No. 106984201 [Patent Document 2] Chinese Patent No. 201480041084.1 Summary of the Invention [Problem to be solved by the invention]

[0010] The market needs improved nanofiber composite technology that can provide high-performance filtration materials with higher efficiency and dust holding capacity while maintaining low flow resistance. The creative medium and technology of the present invention can provide a filtration medium, filtration device, and manufacturing method that can meet this need. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a first embodiment of the composite filtration medium of the present invention. [Figure 2] 1 shows cross-sectional structures of Example 2 and Example 4 of the composite filtration media of the present invention. [Figure 3] 1 is a flow diagram of a method for preparing a composite filtration media of the present invention. [Figure 4] FIG. 10 is a diameter distribution diagram of the nanofiber composite filtration medium of Example 4 of the composite filtration medium of the present invention. [Figure 5] FIG. 10 is a comparison diagram of the dust retention capacity of the composite filtration medium of Example 4 of the present invention and a single-layer nano composite filtration medium. [Figure 6] 5 is a cross-sectional view of a composite filtration medium according to a fifth embodiment of the present invention. [Figure 7] FIG. 10 is a comparison diagram of the dust retention capacity of the composite filtration medium of Example 5 of the present invention and a single-layer nanofiber composite filtration medium. [Figure 8] 1 is a cross-sectional view of a composite filtration medium according to Example 6 of the present invention; [Figure 9] FIG. 10 is a comparison diagram of the dust retention capacity of the composite filtration medium of Example 6 of the present invention, a PIFE membrane composite filtration medium made by a certain Japanese company, and an ultrafine glass fiber composite filtration medium made by a certain American company. [Figure 10] 1 is a scanning electron microscope fiber image of a composite filtration media of the present invention. [Figure 11] 1 is a cross-sectional view of a nanofiber layer between two support layers of a composite filtration media of the present invention. [Figure 12] 1 is a scanning electron microscope fiber image of a composite filtration media of the present invention. [Figure 13] 1 is a scanning electron microscope fiber image of one embodiment of a composite filtration media of the present invention. [Figure 14] FIG. 2 is a fiber diameter distribution diagram of one embodiment of a composite filtration media of the present invention. [Figure 15] 1 is a scanning electron microscope fiber image of one embodiment of a composite filtration media of the present invention. [Figure 16] 1 is a curve showing the pressure drop of a composite filtration medium of the present invention as a function of sodium chloride (NaCl) loading. [Figure 17] 1 is a cross-sectional view of a composite filtration medium according to an embodiment of the present invention, comprising multiple nanofiber layers (11A, 12A, 13A), an inner support layer (21A / 22A), and an outer support layer (31A / 32A). [Figure 18] FIG. 2 is a curve showing the change in pressure loss of three composite filtration media of the present invention depending on the load time. [Figure 19] 1 is a cross-sectional view of a composite filtration media of the present invention in which the nanofiber layer is attached to the bottom of the support layer. [Figure 20] 1 is a cross-sectional view of a composite filtration media of the present invention in which a nanofiber layer is attached on top of a support layer. [Figure 21] FIG. 1 is a cross-sectional view of a composite filtration media of the present invention in which a nanofiber layer is attached on top of a nanofiber support layer. [Figure 22] 1 shows a cross-sectional structure of a composite filtration medium of the present invention in which a nanofiber layer is attached to the bottom of a nanofiber support layer. [Figure 23]1 is a cross-sectional view of the top of a nanofiber support layer with a nanofiber layer attached to the top of the structure of a composite filtration media of the present invention. [Figure 24] 1 is a cross-sectional view of multiple nanofiber layers attached to each layer of a composite filtration media of the present invention. [Figure 25] 1 is a pleated plate filter element comprising a composite filtration media of the present invention. [Figure 26] 1 is a multi-V filter element comprising a composite filtration media of the present invention. [Figure 27] 1 is a cylindrical filter element comprising a composite filtration media of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] To enable those skilled in the art to realize these embodiments, the following describes specific embodiments of the present invention in conjunction with the drawings. Other embodiments may include structural, logical, electrical, process, or other changes. Some content and features of one embodiment may be included in other embodiments, or some content or features of other embodiments may be substituted. The embodiments described in the claims include all available equivalents required by those claims. .

[0013] The objective of the present invention is to solve various problems caused by the dense structure of nanofiber composite filtration media, such as excessively high fiber packing density, high flow resistance, and low dust holding capacity. The present invention provides a composite filtration medium and a preparation method thereof, which uses an inner support layer as a skeleton to maintain the void volume of the nanofiber composite filtration medium and promote the formation of a more open structure between the nanofibers, thereby achieving the goals of high filtration efficiency, low flow resistance, and high dust holding capacity.

[0014] According to the present invention, a nanofiber composite filtration medium with a more open structure can be effectively prepared, and the surface filtration mechanism of the conventional nanofiber composite filtration medium can be transformed into a deep filtration mechanism. This significantly improves the dust retention capacity and quality factor (QF = -ln(1 - efficiency) / dP) of the composite filtration medium, improves the inherent drawbacks of the densely packed nanofiber structure, reduces the interference of the dense structure with the slipstream around the single fiber, and significantly reduces the resistance of the filtration medium to airflow, effectively achieving the high efficiency and low resistance characteristics of the nanofiber composite filtration medium.

[0015] The present invention provides a composite filtration medium comprising a nanofiber layer and an inner support layer disposed below and / or above the nanofiber layer, the inner support layer being used to support the nanofiber layer and reduce its packing density.

[0016] The nanofiber layer contains nanofibers with diameters of 1 nm to 5000 nm, and the inner support layer has a fiber diameter of 100 μm or less.

[0017] In a preferred embodiment, the composite filtration media described in this invention has at least two nanofiber layers, and an inner support layer is disposed between the two nanofiber layers.

[0018] The weight of the inner support layer per unit area is 80g / m 2 The nonwoven fabric is one or a combination of spunbond nonwoven fabric, dry-laid nonwoven fabric, wet-laid nonwoven fabric, meltblown nonwoven fabric, or fiber net.

[0019] The composite filtration media described in this invention preferably have a particle filtration efficiency of a downstream nanofiber layer that is ≥ the particle filtration efficiency of the adjacent upstream nanofiber layer.

[0020] The composite filtration media described in this invention preferably have a particle filtration efficiency of a downstream nanofiber layer that differs by less than 60% from the particle filtration efficiency of the adjacent upstream nanofiber layer.

[0021] In the composite filtration media described in the present invention, the nanofiber layer preferably further comprises nanofibers (1-100 nm), submicron fibers (0.1-1 μm), and optionally micron fibers (>1 μm) with a fiber diameter of 50 μm or less. The fiber diameters of this layer may exhibit a unimodal distribution, with a peak in the nano- or submicron-scale range, or a bimodal / multimodal distribution, with one peak in the nano / submicron-scale range and other peaks in the submicron and / or micron-scale range.

[0022] In a preferred embodiment, the composite filtration medium described in the present invention further comprises an outer support layer located above the top nanofiber layer and / or below and / or between the bottom nanofiber layer, the outer support layer being used to provide strength and rigidity to the composite filtration medium, the outer support layer below the bottom layer being the first outer support layer, and the outer support layer above the top layer being the second outer support layer (combining protection / efficiency / dust retention functions).

[0023] The nanofibers may be made of polymeric or inorganic materials, such as PA6 (polyamide 6), PA56 (polyamide 56), PA66 (polyamide 66), PA1010 (polyamide 1010), PAN (polyacrylonitrile), PLA (polylactic acid), PU (polyurethane), CA (cellulose acetate), PVDF (polyvinylidene fluoride), PI (polyimide), PMIA (poly(m-phenylene isophthalamide)), PIFE (polytetrafluoroethylene), Al2O3 (alumina), SiO2 (silica), and ZrO2 (zirconia). The nanofibers may be continuous filaments and / or short fibers.

[0024] The material of the inner support layer (2 in Figure 1) can be any one of PP (polypropylene), PET (polyethylene terephthalate), PE (polyethylene), PA (polyamide), PVDF (polyvinylidene fluoride), PS (polystyrene), CA (cellulose acetate), PAN (polyacrylonitrile), PET / PE, PET / low-melt PET (PET / LMPET), PLA (polylactic acid), and glass fiber, or a combination thereof. When the inner support layer is two-component, the weight ratio of the surface layer polymer to the core layer polymer is 30 / 70 to 70 / 30. The inner support layer has a monodisperse or polydisperse fiber diameter distribution, with a peak between 0.3 μm and 100 μm.

[0025] The first outer support layer (3 in FIG. 2) can be a spunbond nonwoven, airlaid nonwoven, drylaid nonwoven, wetlaid nonwoven, meltblown or fiber net, with fiber size between 0.3 μm and 100 μm.

[0026] In the composite filtration media of the present invention, the micron / submicron fibers are preferably short fibers or continuous filaments. The micron / submicron fibers are made of polymeric or inorganic materials, and the micron fibers are made of any of the following or any combination thereof: PA6 (polyamide 6), PA56 (polyamide 56), PA66 (polyamide 66), PA1010 (polyamide 1010), PAN (polyacrylonitrile), PLA (polylactic acid), PU (polyurethane), PVDF (polyvinylidene fluoride), PS (polystyrene), CA (cellulose acetate), PI (polyimide), PMIA (poly(m-phenylene isophthalamide)), PIFE (polytetrafluoroethylene), PP (polypropylene), PET (polyethylene terephthalate), PE (polyethylene), PA (polyamide), PET / PE, PET / low melting point PET (PET / LMPET), and glass fibers. In the nanofiber layer, when the nanofiber layer has a multi-component structure, the quantity ratio of the nanofibers to the micron / submicron fibers is 1:6 to 600:1, and the weight ratio is 0.1:99 to 10:1.

[0027] The method for preparing the composite filtration media of the present invention includes the following.

[0028] S1. A nanofiber layer is deposited on an inner support layer and a nanofiber layer is deposited on a first outer support layer by electrospinning. The nanofiber layer comprises nanofibers with a fiber diameter of 1 nm to 5000 nm. The inner support layer is a spunbond nonwoven, dry-laid nonwoven, wet-laid nonwoven, meltblown, or fiber mesh with a fiber diameter of <100 μm.

[0029] S2: An optional second outer support layer (combining protection, efficiency, and dust retention functions) is placed on top of the top nanofiber layer (1 in Figure 1). The nanofiber layer, inner support layer, and outer support layer are then thermocompressed, adhesively bonded, or ultrasonically bonded to obtain a composite filtration medium.

[0030] The present invention relates to a method for preparing a composite filtration medium. As a preferred method, in step S1, the number of inner support layers is ≧1, and their thicknesses and basis weights can be the same or different.

[0031] The first outer support layer (31, FIG. 2) and optional second outer support layer (32, FIG. 2), which may also function as a protective layer, an efficiency layer, or a dust-retaining layer, are spunbonded, dry-laid, wet-laid, meltblown, or other fabricated fiber meshes.

[0032] In a preferred method for preparing a composite filtration medium, in step S1, a nanofiber layer (1, FIG. 1) is obtained by depositing nanofibers alone or nanofibers, micron fibers, and / or submicron fibers simultaneously onto an inner support layer (2, FIG. 1) by electrospinning or a combination of electrospinning and other fiber dispersion methods. The fiber diameter of micron fibers produced by electrospinning is 5 μm or less, while the fiber diameter of micron fibers produced by other fiber spinning and dispersion methods is 60 μm or less. The quantitative ratio of nanofibers to micron and / or submicron fibers is 1:6 to 600:1, and the weight ratio of nano-sized fibers to micron-sized fibers is 0.1:99 to 10:1.

[0033] The present disclosure provides a nanofiber composite filtration medium with high filtration efficiency, low flow resistance, and high dust holding capacity, which is particularly suitable for filtering and separating particles in air or liquid.

[0034] In some embodiments of the present disclosure, a nanofiber composite filtration medium with low flow resistance and high efficiency is comprised of two or more nanofiber layers and one or more inner support layers, with the inner support layers positioned between adjacent nanofiber layers. The nanofiber layers may have the same or different particle filtration efficiencies and flow resistances. The inner support layer comprises one or more of a low basis weight spunbond nonwoven, dry-laid nonwoven, air-laid nonwoven, wet-laid nonwoven, melt-blown nonwoven, or other woven or nonwoven material, with a fiber diameter of 100 μm or less and preferably a thickness of 0.5 mm or less.

[0035] In another embodiment of the present disclosure, a nanofiber composite filtration medium with low flow resistance and high efficiency is comprised of two or more nanofiber layers and one or more inner support layers, with the inner support layers positioned between adjacent nanofiber layers. The nanofiber layers are preferably configured so that particle filtration efficiency increases gradually from the upstream side to the downstream side. The inner support layer is made of uniformly distributed short fibers or filaments, which may be made of any one or any combination of polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), cellulose acetate (CA), PET / PE, PET / low-melt PET (PET / LMPET), and glass fibers.

[0036] In another embodiment of the present disclosure, a low flow resistance, highly efficient nanofiber composite filtration medium is comprised of two or more nanofiber layers and one or more inner support layers disposed between adjacent nanofiber layers, wherein the nanofiber layers are comprised of nanofibers or a combination of nanofibers with submicron and micron fibers, and the nanofiber layers have an extremely small minimum fiber diameter of 5 nm and a large maximum fiber diameter of 50 μm.

[0037] In some embodiments of the present disclosure, the nanofiber layer has a statistical peak in the fiber diameter distribution in the range of 10 nm to 120 nm. In other embodiments, the nanofiber layer has a bimodal or multimodal fiber diameter distribution, with one peak located in the range of 20 nm to 120 nm and other peaks located in any range from 200 nm to 4000 nm or 4 μm to 50 μm.

[0038] In another embodiment of the present disclosure, a nanofiber composite filtration medium having low flow resistance and high filtration efficiency is comprised of two or more nanofiber layers and one or more inner support layers, the inner support layers being disposed between adjacent nanofiber layers.

[0039] The inner support layer is a layer of micron or submicron fibers with fiber diameters between 0.3 μm and 100 μm, produced by electrospinning, other fiber spinning processes, or other fiber distribution and web formation processes. In some embodiments, the micron or submicron fiber layer has a monodisperse fiber diameter distribution, and in other embodiments, a polydisperse distribution with a peak anywhere between 0.3 μm and 100 μm.

[0040] In this specification, unless otherwise specified, the term "high efficiency and low flow resistance" means that the composite filtration media has a filtration efficiency of at least 60% and a flow resistance of not more than 500 Pa when tested in accordance with ISO 29463-3 or other equivalent standards. The term "almost the same" means that the filtration efficiency and flow resistance of different composite filtration media differ by less than 6% when tested in accordance with ISO 29463-3 or other equivalent standards.

[0041] The term "nanofiber" refers to fibers with a fiber diameter between 1 nm and 5000 nm. Nanofibers can be made from polymers such as PA (polyamide), PVDF (polyvinylidene fluoride), PLA (polylactic acid), PES (polyethersulfone), PEI (polyetherimide), CA (cellulose acetate), PS (polystyrene), PAN (polyacrylonitrile), PI (polyimide), and PMIA (poly(m-phenylene isophthalamide)), or inorganic materials such as Al2O3 (alumina), SiO2 (silica), and ZrO2 (zirconia). Nanofibers are typically produced by electrospinning. Generally, if the material is polymeric, a spinnable polymer solution is prepared and then electrospun. If the material is inorganic, a spinnable solution or solution precursor for electrospinning is prepared and then calcined. Nanofibers can be continuous filaments or staple fibers.

[0042] The term "nano-order fibers" refers to fibers with diameters between 5 nm and 100 nm, "submicron-order fibers" refers to fibers with diameters between 0.1 μm and 1 μm, and "micron-order fibers" refers to fibers with diameters greater than 1 μm. Nano-order fibers, submicron-order fibers, and micron-order fibers can be continuous filaments or short fibers, straight fibers or curled fibers, and monocomponent or multicomponent fibers. In some embodiments, the nano-order fibers, submicron-order fibers, and micron-order fibers are made from polymers such as PP and PET. In other embodiments, the nano-order fibers, submicron-order fibers, and micron-order fibers are made from inorganic materials such as ultrafine glass fibers.

[0043] The terms "monocomponent" and "bicomponent" refer to the polymer materials that make up the fiber. Monocomponent refers to a fiber that contains only one polymer component, such as PET or PE. Bicomponent refers to a fiber with a surface and core structure, where the surface polymer covers the core polymer and extends continuously in the longitudinal direction of the fiber. In multicomponent fibers, the surface layer generally uses a low-melting point polymer, such as PE and LMPET, while the core layer generally uses a polymer with a relatively high melting point, such as PET. In bicomponent fibers, the weight ratio of the surface polymer to the core polymer can be 40 / 60, 35 / 65, 50 / 50, or other weight ratios that provide better practical results.

[0044] The term "polymer," also known as a macromolecular compound, refers to a compound with a relative molecular weight ranging from several thousand to several million. Polymeric compounds include homopolymers, copolymers, homopolymer and copolymer mixtures in any weight ratio, and modified polymers prepared by physical and chemical modification methods. In this specification, unless otherwise specified, the term "polymer" includes all spatial configurations of macromolecular compounds, including isotactic, syndiotactic, and atactic structures.

[0045] The term "upstream" refers to the inlet side and the term "downstream" refers to the outlet side.

[0046] The present invention has the following advantages:

[0047] The present invention describes a technical means for producing a high-performance nanofiber filtration medium by dividing a nanofiber layer into multiple nanofiber layers and placing an inner support layer above or below each nanofiber layer, thereby enabling the preparation of a high-performance nanofiber filtration medium even when the nanofiber diameter distribution is narrow, realizing a conversion from the surface filtration mechanism of the nanofiber composite filtration medium to the depth filtration mechanism, and significantly increasing the dust retention capacity of the composite filtration medium.

[0048] The technical means of the composite filtration medium provided by this application can improve the inherent drawbacks of the dense structure of nanofibers, reduce the interference of the dense structure of the nanofiber filtration medium with the slipstream around the single fibers, significantly reduce the resistance of the composite filtration medium to air flow, and effectively achieve high efficiency and low flow resistance of the composite filtration medium.

[0049] The present invention provides a composite filtration medium having a multi-component nanofiber composite structure, which comprises a support layer and a multi-component nanofiber layer, and may be a structure consisting of a support layer and a single nanofiber layer, or a composite structure consisting of an outer support layer, an inner support layer and multiple nanofiber layers.

[0050] Nanofibers with a lofty structure typically have a relatively large diameter. Generally, the fiber diameter is 100 nm to 5 μm, preferably greater than 0.1 μm (100 nm), more preferably greater than 0.3 μm, and even more preferably greater than 0.5 μm, with a loftiness (void volume) greater than 70%. Ultrafine nanofibers have a relatively small diameter, ranging from 10 nm to 300 nm, preferably less than 0.3 μm, more preferably less than 0.15 μm. The diameter of nanofibers with a lofty structure is larger than that of ultrafine nanofibers. The blending weight ratio of fine fibers to large-diameter fibers can be 0.1:99 to 80:20. By adjusting the process parameters, the filtration efficiency of the multi-component nanofiber layer can reach 30% to 99.9999%. Nanofibers with different filtration efficiencies can be prepared by thermocompression bonding, adhesive bonding, or ultrasonic compounding to meet specific application needs.

[0051] Lofty nanofibers and ultrafine nanofibers can be produced by multi-nozzle electrospinning or nozzleless electrospinning techniques. Two or more types of fibers can be mixed during spinning, and the concentrations of the two or more electrospinning solutions can be different, and the polymers used can be the same or different.

[0052] The optional polymer for the lofty nanofibers and ultrafine nanofibers can be one or a combination of more than one of the following polymers: PU (polyurethane), PS (polystyrene), PI (polyimide), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PA (polyamide), PA6 (polyamide 6), PA66 (polyamide 66), PA56 (polyamide 56), PA1010 (polyamide 1010), PAN (polyacrylonitrile), PVDF (polyvinylidene fluoride), PVF (polyethylene fluoride), PTFE (polytetrafluoroethylene), PCTFE (polychlorotrifluoroethylene), PEO (polyethylene oxide), PMMA (polymethyl methacrylate), These include, but are not limited to, poly(m-phenylene isophthalamide) (methacrylate), PMIA (poly(m-phenylene isophthalamide)), PSU (polysulfone), PPSU (polyphenylene sulfone resin), PES (polyethersulfone), PPS (polyphenylene sulfide), PEI (polyetherimide), PLA (polylactic acid), PLLA (L-lactide), PDLA (D-lactide), PCL (polycaprolactone), PVA (polyvinyl alcohol), PVP (polyvinylpyrrolidone), ACRYLIC (acrylic resin), CA (cellulose acetate), CHITOSAN, SILKFIBROIN, and copolymers or homopolymers of the above polymers. Solvents of choice include, but are not limited to, HO (water), EtOH (ethanol), BnOH (benzyl alcohol), FA (formic acid), AcOH (acetic acid), ACETONE (acetone), DMF (N,N-dimethylformamide), DMAC (N,N-dimethylacetamide), DMSO (dimethyl sulfoxide), NMP (N-methylpyrrolidone), DCM (dichloromethane), CHLOROFORM (trichloromethane), HFIP (hexafluoroisopropanol), THF (tetrahydrofuran), TFA (trifluoroacetic acid), TFE (tetrafluoroethylene), and the like.

[0053] The present invention provides a multi-component nanofiber composite structured composite filtration medium, the preparation method of which comprises the following steps:

[0054] One, two or more polymers are added to the same or different solvents and stirred until completely dissolved, to obtain two or more electrospinning solutions with the same or different mass percent concentration and viscosity, with a mass concentration range of 1 wt% to 70 wt%.

[0055] The technical means provided by the present application can achieve the following advantageous effects:

[0056] (1) Even if the distribution of nanofiber diameters is narrow, the technical means of this application can effectively prepare a composite filtration medium with a lofty structure, realize the transformation of the nanofiber composite filtration medium from a surface filtration mechanism to a depth filtration mechanism, and significantly increase the dust retention capacity.

[0057] (2) The technical means of the composite filtration medium provided in this application overcomes the drawbacks of dense layer structure, improves the bulkiness and porosity of the nanofiber composite filtration medium, reduces the flow resistance, and increases the dust holding capacity.

[0058] The present invention provides, among other things, a composite filtration medium having a multicomponent nanofiber composite structure, including a support layer and a multicomponent nanofiber layer, and may be a structure consisting of a support layer and a single nanofiber layer, a composite structure consisting of an outer support layer, inner support layer(s), and multiple nanofiber layer(s), or a structure comprising one or more inner support / separation layer(s) and one or more nanofiber layers.

[0059] Nanofibers with a lofty structure generally have a relatively large diameter. The fiber diameter is typically 100 nm to 5 μm, preferably greater than 0.1 μm (100 nm), more preferably greater than 0.3 μm, and even more preferably greater than 0.5 μm. The loftiness (void volume) is 70% or greater. Fine nanofibers have a relatively small fiber diameter, 10 nm to 300 nm, preferably less than 0.3 μm, more preferably less than 0.15 μm. The fiber diameter of nanofibers with a lofty structure is larger than that of fine nanofibers. The mass ratio of large-diameter nanofibers to fine nanofibers can be adjusted within a range of 10:90 to 99:0.1. By adjusting process parameters, the filtration efficiency of the multicomponent nanofiber layer can be adjusted to 30% to 99.99995%. Nanofibers with different filtration efficiencies can be combined by hot pressing, adhesive bonding, or ultrasonic compounding to meet specific application needs.

[0060] Nanofibers and fine nanofibers with lofty structures can be prepared by multi-nozzle or nozzleless electrospinning. Multiple types of fibers are mixed during the spinning process, and the concentrations of the two or more electrospinning solutions used can be different, and the polymers used for electrospinning can be the same or different.

[0061] The polymer used for the lofty nanofibers and fine nanofibers may be one or a combination of more than one of the following examples, and the selection of polymers is not limited to the following: polyurethane, polystyrene, polyimide, polyethylene glycol terephthalate, polybutylene terephthalate, nylon (nylon 6, nylon 66, nylon 56, nylon 1010), polyacrylonitrile, polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, chlorotrifluoroethylene, polyethylene oxide, polymethyl methacrylate, poly(m-phenylene isophthalamide), polysulfone, polyphenylene sulfone resin, polyethersulfone, polyphenylene sulfide, polyetherimide, polylactic acid, poly-L-lactide, poly-D-lactide, polycaprolactone, polyvinyl alcohol, polyvinylpyrrolidone, acrylic resin, cellulose acetate, chitosan, silk fibroin, and copolymers or homopolymers of these polymers. Solvent choices include, but are 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, and the like.

[0062] The present invention provides a composite filtration medium with a multi-component nanofiber composite structure, the preparation method of which comprises the following steps: adding one or more polymers to the same or different solvents, respectively, and stirring until completely dissolved, to obtain two or more electrospinning solutions with the same or different mass percent concentrations and viscosities, the mass concentration range of which is 1 wt% to 70 wt%.

[0063] The technical means provided in this application can achieve the following beneficial effects:

[0064] (1) Even when the fiber diameter distribution of nanofibers is narrow, the proposed scheme can effectively prepare a composite filtration medium with a lofty structure, realize the transformation of the nanofiber filtration medium from a surface filtration mechanism to a deep filtration mechanism, and significantly improve the dust retention capacity.

[0065] (2) The technical configuration of the composite filtration medium provided by this application overcomes the drawback of dense layer structure, improves the loftiness (void volume) and porosity of the nanofiber composite filtration medium, reduces resistance, and improves dust retention capacity.

[0066] As used herein, unless otherwise specified, "high efficiency and low flow resistance" means that the composite filtration media has a filtration efficiency of at least 60% and a flow resistance of not more than 500 Pa when tested in accordance with ISO 29463-3 or other equivalent standards. The term "nearly the same" means that the composite filtration media has a difference in filtration efficiency and flow resistance of less than 6% when tested in accordance with ISO 29463-3 or other equivalent standards. The terms "inner support layer," "spacing layer," and "separation layer" are synonymous.

[0067] Unless otherwise specified, the term "nanofiber" as used herein refers to a fiber having a diameter of 1 nm to 5000 nm. Nanofibers can be made from polymers such as PA (polyamide), PVDF (polyvinylidene fluoride), PLA (polylactic acid), PES (polyethersulfone), PEI (polyetherimide), CA (cellulose acetate), PS (polystyrene), PAN (polyacrylonitrile), PI (polyimide alumina), and PMIA (poly(m-phenylene isophthalamide)), or inorganic materials such as Al2O3 (alumina), SiO2 (silica), and ZrO2 (zirconia). Generally, nanofibers are produced by electrospinning. When the material is a polymer, a spinnable solution of the polymer must be prepared before electrospinning. When the material is an inorganic material, a spinnable sol or solution precursor is prepared, followed by electrospinning and calcination. Nanofibers can be continuous filaments or staple fibers.

[0068] As used herein, unless otherwise specified, the terms "monocomponent" and "bicomponent" refer to the polymeric materials that make up a fiber. Monocomponent refers to a fiber that contains only one polymer component, such as PET or PE. Bicomponent refers to a fiber that is made up of two polymers. As used herein, multicomponent nanofibers are nanofibers with different structures and diameters within the nanofiber layer, i.e., a mixture of lofty nanofibers and fine nanofibers.

[0069] As used herein, unless otherwise specified, the term "polymer" (also referred to as a polymeric compound) refers to a compound having a relative molecular weight ranging from several thousand to several million. Polymeric compounds include homopolymers, copolymers, homopolymer and copolymer mixtures in any weight ratio, and modified polymers prepared by physical and chemical modification methods. As used herein, unless otherwise specified, the term "polymer" includes all spatial configurations of polymeric compounds, such as isotactic, syndiotactic, and atactic structures.

[0070] In this specification, unless otherwise stated, the term "loftiness" or "lofty" corresponds to the void volume (also known as porosity) and refers to the volume not occupied by solid matter in a porous material. The formula is: Void volume = 1 - [weight per unit area / volume x density], Porosity = loftiness = void volume.

[0071] In this specification, unless otherwise stated, the term "number" ratio of fibers refers to the number of fibers observed in a scanning electron microscope image.

[0072] In order to achieve better filter structure and performance in automobile cockpit air filtration and other air filtration for removing particle and gas pollutants, composite filter media with high filtration efficiency, low flow resistance, high dust holding capacity, small thickness, and good rigidity are expected.

[0073] However, current technology has significant limitations. For example, to achieve a filtration medium with the following properties:

[0074] 1. Low flow resistance (e.g., flow resistance at 30cm / s≦30Pa)

[0075] 2. Small thickness (e.g., ≦1mm)

[0076] 3. High dust holding capacity (e.g., at 30cm / s, the final pressure drop is less than 150Pa, and the ASHRAE dust holding capacity (excluding fiber dust) is 30g / m 2 ), prior art filtration media have low filtration efficiencies, ranging from 25% to 38% at a flow rate of 16.7 cm / s.

[0077] In this case, the filtration efficiency is low, so particulate matter cannot be sufficiently removed, and the filtration performance of the medium is low.

[0078] Additionally, if a large amount of particulate contaminants reaches the activated carbon bed, the effective area of ​​the activated carbon may be reduced, reducing its gas adsorption efficiency and capacity.

[0079] Similarly, in many prior art practices, increasing filtration efficiency without increasing the thickness and weight per unit area of ​​the composite filtration media can result in a significant increase in resistance and a decrease in dust holding capacity. For example, increasing efficiency by 50% or more can result in a resistance of over 40 Pa and a dust holding capacity of approximately 10 g / m at a flow velocity of 30 cm / s. 2 (Tested using ASHRAE dust (no fiber dust) at 30 cm / s and a final pressure drop of 150 Pa.)

[0080] Furthermore, in the prior art, high permeability of the substrate can lead to activated carbon leakage. To reduce the resistance of the filter media, the substrate can be designed with high permeability and low resistance. However, high permeability can cause carbon particles to penetrate the substrate and fall off the composite filtration media. Therefore, in the prior art, low permeability substrates or large particle activated carbon are used to prevent leakage. However, low permeability substrates generally have high resistance. Compared to fine particle activated carbon, the use of large particle activated carbon increases the thickness of the filtration media, resulting in reduced adsorption efficiency. These two technical solutions negatively affect the overall performance of the composite filtration media.

[0081] In addition to other embodiments, the composite filtration media of the present invention may include 1) a support layer, 2) an electrospun nanofiber layer on the support layer, 3) an adsorbent layer on the nanofiber layer, and 4) an overlayer disposed on the adsorbent layer, which may be a meltblown material, a triboelectrically charged medium, a dry-laid medium, a wet-laid medium, a spunbond medium, or any one or more of the foregoing media with a nanofiber coating on the top or bottom thereof, and / or any combination thereof.

[0082] In at least one embodiment, the adsorbent material can be selected from activated carbon, activated carbon containing adhesive powder, and other adsorbent materials.

[0083] In at least one embodiment, the upper layer can have significant filtration efficiency. In at least one embodiment, the upper layer can have significant dust holding capacity.

[0084] In at least one embodiment, adjacent layers can be bonded by any method selected from ultrasonic bonding, hot melt spray bonding, powder heating composite bonding, and adhesive transfer composite bonding. In at least one embodiment, the nanofibers can be selected from any one or combination of PVDF (polyvinylidene fluoride), polyamide, CA (cellulose acetate), PS (polystyrene), PAN (polyacrylonitrile), PI (polyimide), PMIA (poly(m-phenylene isophthalamide)), TPU (thermoplastic polyurethane), PEI (polyetherimide), PLA (polylactic acid), and PES (polyethersulfone).

[0085] In at least one embodiment, the substrate can be a thermoplastic polymer. In at least one embodiment, each of the at least two layers has antimicrobial properties.

[0086] In at least one embodiment, the nanofibers can be selected from any one or combination of nozzle electrospun nanofibers, nozzleless electrospun nanofibers, centrifugal spun nanofibers, and electroblowing spun nanofibers.

[0087] In at least one embodiment, at least a portion of the filtration media can be provided with a high concentration (5-50%) of an active ingredient, such as VC (vitamin C), by electrostatic spraying and electrospinning or coating methods.

[0088] In at least one embodiment, the nanofibers have a diameter of less than 1 μm. In at least one embodiment, the nanofibers have a diameter of less than 0.3 μm. In at least one embodiment, the nanofibers have a diameter of less than 0.15 μm.

[0089] The present invention provides an improved nanofiber composite technology that can provide a high-performance filtration medium with higher filtration efficiency and higher dust holding capacity while maintaining low flow resistance and small thickness.

[0090] The present invention further provides an improved nanofiber composite technology, which can provide a high-performance filtration medium with lower flow resistance and higher dust holding capacity while maintaining the same efficiency and thickness as other filtration media. It can also reduce flow resistance and increase efficiency while maintaining the same dust holding capacity and thickness. It can also increase filtration efficiency, reduce flow resistance, and increase dust holding capacity without changing the thickness, thereby improving the overall filtration performance of the filtration device. It can also better control and ensure the thickness and rigidity of the filtration medium.

[0091] In some embodiments, the nanofiber composite filtration media of the present invention contain an active ingredient with antibacterial and / or release capabilities (e.g., vitamin C (VC)). In the prior art, any antibacterial and antiviral functionality of the filtration media has been located in the substrate layer, but this placement method has limited the overall antibacterial and antiviral functionality of the filtration media because bacterial and viral particles are typically trapped in the efficiency layer rather than the substrate layer. The present invention allows the antibacterial and antiviral functionality to be located in all layers, including the substrate layer. In some embodiments, the antibacterial functionality is located in the meltblown layer and / or the nanofiber layer.

[0092] In some embodiments, electrostatic spraying and electrospinning can be used to load high concentrations of active ingredients (such as VC) onto the filter media, which are released by moisture in the air, providing health benefits and humidifying the air for increased comfort. In some embodiments of the present invention, an air composite filtration media structure 1B includes a nanofiber layer 10B attached to a support layer 20B. As shown, an activated carbon layer 30B is located above the support layer, and a large pore fibrous material layer 40B is located above the carbon layer 30B. A protective layer 50B can be disposed on the relatively large pore fibrous material layer. Note that all figures are for illustrative purposes only, and the location of each layer may differ from that shown in the figures. For example, the large pore fibrous material layer 40B can be located below the support layer 20B (i.e., at the bottom of the support layer 20B). The support layer 20B can improve the rigidity and / or structural strength of the composite filtration media 1B. As shown in FIG. 25, the nanofiber layer 10B located at the bottom of the support layer 20B can increase the overall efficiency of the filtration media while also overcoming particle leakage and capturing fine particles released from the activated carbon during processing of the filtration media and use of the filtration device. This nanofiber coating layer 10B can be applied to the top and / or bottom of the support layer 20B. In Figure 19, nanofiber layer 10B is attached on top of support layer 20B.

[0093] In Figure 20, the nanofiber layer / coating layer is disposed between the activated carbon layer (also called the adsorbent layer) 30B and the large pore fibrous material layer 40B (including one or more of meltblown nonwoven fabric, filter fabric, spunbond nonwoven fabric, and wetlaid nonwoven fabric). Here, a nano support layer 25B is further included. If the nanofiber layer 10B is not disposed on the support layer 20B, the nano support layer 25B can support the nanofiber layer 10B. Because the carbon layer 30B and / or the large pore fibrous material layer 40B may not provide adequate structural support for the nanofiber layer 10B, an additional nano support layer can be used.

[0094] In Figure 21, nanofiber layer 10B is on top of filtration media 3B. Here, the nanofiber layer is attached to the bottom of nano-support layer 25B. However, as shown in Figure 20, nanofiber layer 10B can also be attached to the top of nano-support layer 25B.

[0095] As shown in Figure 22, filtration media 4B can use multiple nanofiber layers 10B. Here, the figure shows three different nanofiber layers 10B1, 10B2, and 10B3. Because nanofiber layers 10B1-3 require support, a nano-support layer 25B can be attached to nanofiber layer 10B. A nanofiber layer can be placed on either side of support layer 20B and each nano-support layer 25B. As shown in Figure 23, filtration media 5B has nanofiber layers 10B on the top and bottom.

[0096] In Figure 23, nanofiber layer 10B1 is placed on top of filtration media 6B rather than on the bottom. Figures 20-24 do not include protective layer 50B. In this case, large pore fibrous material layer 40B is protected by nanofiber layer 10B / 25B.

[0097] Nanofibers 10B have multiple applications and arrangements in filtration media structures (e.g., Structures 1B-6B). While not all arrangements are shown in the figures, the present invention recognizes and claims protection for the following arrangements: 1) nanofibers 10B in the inner or outer layer of the filtration media, 2) multiple nanofiber layers 10B in the inner and / or outer layers of the filtration media, and 3) multiple nanofiber layers 10B, with at least one nanofiber layer on the exterior and at least one located on the interior of the filtration media.

[0098] In some embodiments, the nanofibers are disposed on top of the lower layer or on top of the upper layer, hi some embodiments, the nanofibers are disposed on the bottom of the lower layer and the bottom of the upper layer.

[0099] The present invention can realize a filtration medium with high efficiency, low pressure loss, long service life, and other functions and safety features mentioned above. In automotive cabin air filtration and other air filtration applications, it is desirable for the core composite filtration medium to have high filtration efficiency, low flow resistance, high dust collection capacity, long service life, thin structure, and excellent rigidity. However, the prior art still has significant limitations.

[0100] For example, low flow resistance (e.g., 30 Pa or less at a flow velocity of 30 cm / s), small thickness (e.g., 1 mm or less), and high dust retention capacity (e.g., 30 g / m at a flow velocity of 30 cm / s at a terminal pressure of 150 Pa in ASHRAE dust). 2 ), conventional filtration media generally have low filtration efficiencies, ranging from 25% to 38% at a flow rate of 16.7 cm / s. Low filtration efficiencies can result in insufficient removal of particulate matter, resulting in insufficient filtration performance. As a result, a large amount of particulate contaminants can reach the activated carbon layer, reducing the effective surface area of ​​the activated carbon and potentially reducing gas adsorption efficiency and adsorption capacity. In conventional filtration media, attempts to improve filtration efficiency while maintaining constant thickness and weight per unit area generally tend to result in increased flow resistance and decreased dust retention capacity. For example, improving filtration efficiency by more than 50% results in flow resistance exceeding 40 Pa and dust retention capacity of approximately 10 g / m. 2 It drops to the following:

[0101] In the prior art, the high permeability of the substrate can lead to the problem of activated carbon leakage. To reduce the flow resistance of the filter material, substrates with high permeability and low resistance are typically used. However, if the substrate is too permeable, activated carbon particles may leak through the substrate and fall off the composite filtration media. To avoid this leakage problem, prior art methods have chosen substrates with low permeability or used activated carbon with large particle sizes. However, substrates with low permeability generally have the disadvantage of increased flow resistance. Furthermore, using large particle sizes of activated carbon increases the thickness of the filtration material, which tends to reduce adsorption efficiency compared to fine particle activated carbon. Both of these approaches can have a negative impact on the overall performance of the composite filtration media.

[0102] The nanofiber composite technology of the present invention provides a high performance filtration material compared to some prior art filtration materials.

[0103] 1. Filtration efficiency can be improved and dust holding capacity can be increased while maintaining flow resistance and thinness.

[0104] 2. It is possible to reduce flow resistance and increase dust holding capacity while maintaining constant filtration efficiency and thickness.

[0105] 3. It is possible to reduce flow resistance and improve filtration efficiency while maintaining the dust holding capacity and thickness constant.

[0106] 4. By improving filtration efficiency, reducing flow resistance, and increasing dust collection capacity while maintaining thickness, the overall filtration performance of the filter material can be greatly improved, and the thickness and rigidity of the filter material can be well controlled and guaranteed.

[0107] In some embodiments, nanofibers are spun by needle or nozzleless (needleless) electrospinning or other methods. These nanofibers can be electrospun onto one or both sides of a highly breathable substrate, or the nanofiber-spun substrate can be composited with a highly breathable substrate. The nanofiber-containing substrate can be combined with a centrally located activated carbon layer, and then a meltblown nonwoven, a triboelectric charging medium, or a nonwoven having a nanofiber coating on one or both sides can be placed on top of the nanofiber-containing substrate. These layers can be combined by spray application of adhesive, adhesive film transfer techniques, ultrasonic bonding, or thermal lamination with powder adhesives.

[0108] In some embodiments, the nanofibers can be selected from PVDF (polyvinylidene fluoride), nylon (polyamide), CA (cellulose acetate), PS (polystyrene), PAN (polyacrylonitrile), PI (polyimide), PMIA (poly(m-phenylene isophthalamide)), TPU (thermoplastic polyurethane), PEI (polyetherimide), PLA (polylactic acid), PES (polyethersulfone), etc., or any combination thereof.

[0109] In at least one inventive method,

[0110] 1. Mix and stir the polymer material and the solvent with or without additives to prepare a solution.

[0111] 2. Nanofibers are spun onto the support layer by electrospinning (electrospinning parameters: flow rate 0.003-0.3 ml / min / nozzle, voltage 10-70 kV, DCD 10-30 cm, ambient temperature and humidity: 10-35°C, 15-45%).

[0112] 3. Sprinkle the adsorbent material (activated carbon with or without adhesive powder) onto the support layer covering the nanofibers.

[0113] 4. An upper layer with or without significant filtration efficiency and dust retention capacity is placed on top of the adsorbent layer containing the adsorbent material. This upper layer can be a meltblown nonwoven, a triboelectric charging medium, or a dry-laid or wet-laid nonwoven with or without a nanofiber coating on one or both sides.

[0114] 5. In some embodiments, the bonding method between the layers can be ultrasonic bonding, hot melt spray, powder heating compounding, or adhesive transfer compounding.

[0115] In some embodiments, the nanofibers have a diameter of less than 1 mm, preferably less than 0.3 mm, and more preferably less than 0.15 mm. In some embodiments, the air flow resistance is 2-30 Pa at a flow rate of 5.33 cm / s. In some embodiments, the filtration efficiency is 20-95% at a flow rate of 5.33 cm / s. In some embodiments, the highly breathable substrate has an air permeability of 2000-5000 L / m 2 / min, the weight per unit area of ​​meltblown nonwoven fabric is 10-15g / m 2 , filtration efficiency is 10-95%, and the weight per unit area of ​​triboelectric material is 20-70g / m 2 , filtration efficiency is 10-95%.

[0116] In some embodiments, the filtration media has an overall filtration efficiency of 30-99% and a dust holding capacity of 20-80 g / m 2 The air flow resistance can be controlled at 4-40 Pa (at a flow rate of 5.33 cm / s), the thickness is about 0.55-1.5 mm, and the amount of activated carbon adsorbent used is 50-700 g / m 2 is.

[0117] [Example 1] As shown in FIG. 1, the composite filtration medium includes a nanofiber layer 1 and an inner support layer 2 disposed below and / or above the nanofiber layer 1, where the nanofiber layer 1 filters and blocks dust and other particulate matter, and the inner support layer 2 supports the nanofiber layer 1 and is used to reduce the overall packing density of the nanofibers.

[0118] The nanofiber layer 1 contains nanofibers with a diameter of 1 nm to 5000 nm, and the fiber diameter of the inner support layer 2 is 100 μm or less.

[0119] [Example 2] As shown in Figure 2, the composite filtration medium includes nanofiber layers 11, 12, 13, 14, 15, and 16, inner support layers 21, 22, 23, 24, and 25, an outer support layer 3 / 31 below the bottom nanofiber layer 11, and an outer support layer 32 above the top nanofiber layer 16. The inner support layer is used to support the nanofiber layers and reduce the overall packing density of the nanofibers.

[0120] Nanofiber layers 11-16 contain nanofibers with diameters of 1 nm to 5000 nm, and inner support layers 21-25 have fiber diameters of 100 μm or less.

[0121] The number of nanofiber layers does not have to be as many as shown in the figure, but at least two layers are required, with inner support layers positioned between adjacent nanofiber layers.

[0122] The inner support layer 21-25 has a weight per unit area of ​​80 g / m 2The nonwoven fabric is one or a combination of spunbond nonwoven fabric, dry-laid nonwoven fabric, wet-laid nonwoven fabric, melt-blown nonwoven fabric, or fiber mesh.

[0123] Preferably, the particulate matter filtration efficiency of a downstream nanofiber layer ≥ the adjacent upstream nanofiber layer.

[0124] The difference in particle filtration efficiency between the downstream nanofiber layer and the adjacent upstream nanofiber layer is less than 60%.

[0125] The nanofiber layer can include submicron and micron fibers with diameters of ≦5 μm. The fiber diameters of the nanofiber layer can be unimodal, with the peak value in the nanoscale (5-100 nm) range. Furthermore, the nanofiber layer can have a bimodal or multimodal distribution, with one peak in the nanoscale (5-100 nm) range and other peaks in the submicron or micron scale range.

[0126] The outer support layers 32 / 31 are used to provide strength and rigidity to the composite filtration media. The outer support layer below the bottom nanofiber layer 11 is the first outer support layer 31, and the outer support layer above the top nanofiber layer 16 is the second outer support layer 32. The outer support layer can serve as one or more of a protective layer, an efficiency layer, or a dust retention layer. The inner support layer can also serve as one or more of an efficiency layer, a dust retention layer, or a separation layer.

[0127] The materials for nanofibers and submicron / micron fibers are polymers or inorganic. Nanofibers include PA6 (polyamide 6), PA56 (polyamide 56), PA66 (polyamide 66), PA1010 (polyamide 1010), PAN (polyacrylonitrile), PLA (polylactic acid), PU (polyurethane), PVDF (polyvinylidene fluoride), PEI (polyetherimide), PMIA (poly(m-phenylene isophthalamide)), PS (polystyrene), PEO (polyethylene oxide), PVA (polyvinyl alcohol), CA (cellulose acetate), PC (polycarbonate), PMMA (polymethyl methacrylate), Al2O3 (alumina), and SiO2 (silica). 、 You can choose from ZrO2 (zirconia) or glass fiber.

[0128] The nanofibers can be continuous filaments and / or discontinuous staple fibers.

[0129] The material of the inner support layers 21-25 is one or a combination of PP (polypropylene), PET (polyethylene terephthalate), PE (polyethylene), PA (polyamide), PVDF (polyvinylidene fluoride), PAN (polyacrylonitrile), PS (polystyrene), PLA (polylactic acid), PET / PE, PET / LMPET (PET / low melting point PET), and GLASS FIBER. When the inner support layer is made of bicomponent fiber, the weight ratio of the surface layer polymer to the core layer polymer is 30 / 70 to 70 / 30, or 20 / 80 to 80 / 20, or 10 / 90 to 90 / 10.

[0130] The fiber diameter of the inner support layer can be 0.3 μm to 100 μm. The inner support layer may have a monodisperse fiber diameter distribution, or a polydisperse fiber diameter distribution with a peak value in the range of 0.3 μm to 100 μm.

[0131] The inner support layer has a weight per unit area of ​​80 g / m 2The nonwoven may be one or a combination of spunbond nonwoven, dry laid nonwoven, wet laid nonwoven, melt blown nonwoven or fiber mesh.

[0132] Micron fibers are uniformly distributed short fibers or continuous filaments, and the material can be polymeric or inorganic, such as PA6 (Polyamide 6), PA56 (Polyamide 56), PA66 (Polyamide 66), PA1010 (Polyamide 1010), PAN (Polyacrylonitrile), PLA (Polylactic acid), PU (Polyurethane), PS (Polystyrene), PVDF (Polyvinylidene Fluoride), PEI (Polyetherimide), PI (Polyimide), PMIA (Poly(m-phenylene isophthalamide)), PTFE (Polytetrafluoroethylene), PMMA (Polymethyl methacrylate), CA (Cellulose Acetate), Al2O3 (Alumina), SiO2 (Silica). 、 The material can be selected from any one of ZrO2 (zirconia), PP (polypropylene), PE (polyethylene), PET (polyethylene terephthalate), PET / PE, PET / low melting point PET (PET / LMPET), and glass fiber, or a combination thereof.

[0133] In the nanofiber layer, the quantity ratio of nanofibers to micron / submicron fibers is 6:1 to 600:1, and the weight ratio is 1:99 to 10:1.

[0134] [Example 3] As shown in FIG. 3, the method for preparing the composite filtration medium includes the following steps:

[0135] S1: Forming a nanofiber layer 11 on the inner support layer 21 and the first outer support layer 31 by electrospinning. The nanofiber layer 11 comprises nanofibers with a diameter of 1 nm to 5000 nm, and the inner support layer 21 can be any one or combination of spunbond nonwoven fabric, dry-laid nonwoven fabric, wet-laid nonwoven fabric, meltblown nonwoven fabric, and / or fiber mesh with a fiber diameter of <100 μm.

[0136] There is at least one inner support layer, which may have different thicknesses and weights per unit area. The first outer support layer 31 may be any one or combination of spunbond nonwovens, drylaid nonwovens, wetlaid nonwovens, meltblown nonwovens, and / or fiber meshes with fiber diameters <100 μm.

[0137] The nanofiber layer can be formed by depositing nanofibers alone or simultaneously depositing nanofibers, micron fibers, and submicron fibers on the inner support layer using electrospinning, airlaid, or a combination of aerodynamic fiber dispersion and web formation. The nanofiber diameter is ≦100 μm. The quantity ratio of nanofibers to micron / submicron fibers is 6:1 to 600:1, and the weight ratio is 1:99 to 10:1.

[0138] Preferably, the filtration efficiency of the nanofiber layer 1 increases from top to bottom.

[0139] S2, a second outer support layer 32 is disposed above the top nanofiber layer 16. The nanofiber layer, inner support layer, and outer support layer are composited by heat pressing, adhesive bonding, and / or ultrasonic bonding to obtain a composite filtration medium.

[0140] The second outer support layer 32 can be any one or combination of a spunbond nonwoven, an airlaid nonwoven, a drylaid nonwoven, a wetlaid nonwoven, a meltblown nonwoven, or a fiber mesh.

[0141] [Example 4] As shown in Figures 2 and 3, the preparation method of the composite filtration media is as follows.

[0142] Step 1: PVDF nanofiber layer 1 was electrospun to a thickness of 0.09 mm and a weight per unit area of ​​15 g / m. 2The nanofiber layer was deposited on a PET / PE bicomponent spunbond nonwoven substrate 2 (surface layer: PE, core layer: PET) to prepare composite filtration media with filtration efficiencies of 30%, 50%, 70%, 80%, and 90%, respectively. A PVDF nanofiber layer 1 was electrospun to a thickness of 0.16 mm and a weight per unit area of ​​35 g / m. 2 The nanofibers were deposited on a PET / PE two-component spunbond nonwoven substrate 2 (surface layer: PE, core layer: PET) to obtain a nanofiber-spunbond nonwoven substrate composite filtration medium with a filtration efficiency of 95%.

[0143] Step 2: The PET / PE bicomponent spunbond nonwoven fabric substrate (second support layer 32) and the nanofiber filtration media prepared in Step 1, each with a filtration efficiency of 30%, 50%, 70%, 80%, 90%, and 95%, are arranged from top to bottom in this order. Next, the arranged composite filtration media are subjected to a composite treatment using heat-pressing rolls at a temperature of 145°C with a roll spacing of 0.5 mm, resulting in a nanofiber composite filtration media with high filtration efficiency and low pressure loss.

[0144] The nanofiber composite filtration medium has a filtration efficiency of 99.99% and a pressure drop of 142.1 Pa for NaCl polydisperse aerosols with a mass median of 0.26 μm and a quantity median of 75 nm at a flow rate of 5.33 cm / s. A predetermined concentration of polydisperse DEHS aerosol was continuously added to the composite filtration medium and a single-layer nanofiber composite filtration medium with a filtration efficiency of 99.99%, and the pressure drop change curves for the two composite filtration media were obtained, showing how the pressure drop changed with the amount of DEHS added. The structures are shown in Figure 2. There are six nanofiber layers 1: 11, 12, 13, 14, 15, 16. There are five inner support layers 2: 21, 22, 23, 24, 25, 31, 32. The diameter distribution of the electrospun nanofiber media is shown in Figure 4, and the dust retention capacity is compared to that of a single-layer electrospun nanofiber filtration media in Figure 5.

[0145] [Example 5] Step 1: The weight per unit area is approximately 20g / m 2 The pressure-sensitive adhesive (PSA) was sprayed online onto a PET spunbond nonwoven fabric substrate with a thickness of approximately 0.12 mm, and the applied amount of the pressure-sensitive adhesive was approximately 2.5 g / m 2 Before the pressure-sensitive adhesive was cured, a PVDF nanofiber layer 1 (Figure 1) was electrospun onto the PET spunbond nonwoven substrate to obtain a nanofiber-spunbond nonwoven substrate composite filtration medium with filtration efficiencies of 90% and 95%, respectively.

[0146] The weight per unit area is approximately 35g / m 2 The pressure-sensitive adhesive was sprayed online onto a PET spunbond nonwoven fabric substrate with a thickness of about 0.16 mm, and the applied amount of the pressure-sensitive adhesive was about 2.5 g / m. 2 Before the pressure-sensitive adhesive was cured, a PVDF nanofiber layer 1 (Figure 1) was deposited onto the PET spunbond nonwoven substrate by electrospinning, resulting in a nanofiber-spunbond nonwoven substrate composite filtration medium with a filtration efficiency of 98%.

[0147] Step 2: The thickness is 0.16 mm and the weight per unit area is 35 g / m 2 The pressure-sensitive adhesive was sprayed online onto the underside of the PET spunbond nonwoven fabric substrate (second outer support layer 32) at a coating amount of about 2.5 g / m 2 Next, a PET spunbond nonwoven fabric substrate, a composite filtration medium with a filtration efficiency of 90% prepared in step 1, and a composite filtration medium with a filtration efficiency of 95% (the weight per unit area of ​​the support layer is 20 g / m 2 ), a composite filtration medium with a filtration efficiency of 98% (the weight per unit area of ​​its support layer is 35g / m 2 ) are arranged from top to bottom, with each nanofiber layer 1 being placed between adjacent spunbond nonwoven fabric substrates 2. The aligned composite filtration media is subjected to a composite treatment using a heat-pressing roller at a temperature of 140°C with a roller spacing of 0.4 mm, to obtain a composite filtration media with high filtration efficiency and low pressure loss (flow resistance).

[0148] The nanofiber composite filter media has a filtration efficiency of 99.99% and a pressure drop of 119.5 Pa for NaCl polydisperse aerosols with a mass median of 0.26 μm and a quantity median of 75 nm at a flow rate of 5.33 cm / s. Cigarette smoke was continuously injected into the nanofiber composite filter media and the PTFE composite filter media with a filtration efficiency of 99.99% at a predetermined concentration and constant air flow rate. The pressure drop (flow resistance) curves for the two filter media with respect to smoke injection were obtained, and their structures are shown in Figure 6. The nanofiber layer 1 has three layers: 11, 12, and 13. The inner support layer 2 has two layers: 21, 22, and 21-micron fiber layers. 31, 32, are the first and second outer support layers. The diameter of the nanofiber composite filtration medium is shown in Figure 6, and a comparison of the dust retention behavior of the nanofiber composite filtration medium prepared in this example and the PTFE composite filtration medium is shown in Figure 7.

[0149] [Example 6] As shown in FIG. 3, the preparation method of the composite filtering material includes the following steps:

[0150] Step 1 (Figure 1): Nanofibers, submicron fibers, and optional micron fibers are fabricated to a thickness of 0.12 mm and a weight per unit area of ​​20 g / m. 2 The nanofiber layer 1 was simultaneously deposited on a PET / PE spunbond nonwoven substrate 2 (the surface layer was PE, the core layer was PET, and the surface layer accounted for approximately 40% of the weight of the PE). Composite filtration media with a nanofiber layer 1 and spunbond nonwoven substrate 2 were prepared with filtration efficiencies of 50%, 70%, and 90%, respectively. The PVDF nanofiber layer 1 was 0.16 mm thick and had a weight per unit area of ​​35 g / m. 2 The nanofiber layer 1 is deposited online onto a PET / PE spunbond nonwoven substrate 2 (the surface layer is PE, the core layer is PET, and the surface layer PE accounts for approximately 40% of the weight), resulting in a composite filtration medium of nanofiber layer 1 and spunbond nonwoven substrate 2 with a filtration efficiency of 99%.

[0151] Step 2: Using the PET / PE bicomponent spunbond nonwoven substrate, the composite filtration medium prepared in Step 1 with a filtration efficiency of 50%, a filtration efficiency of 70%, a filtration efficiency of 90%, and a filtration efficiency of 99% (the weight of the support layer per unit area is approximately 35 g / m). 2 ) are arranged from top to bottom, with the nanofiber layer 1 being placed between two adjacent spunbond nonwoven fabric substrates 2. The aligned composite filtration media can be subjected to a composite treatment using heat-pressing rolls at a temperature of 145°C and a roll gap of 0.4 mm. Finally, a composite filtration media with high filtration efficiency and low pressure loss can be obtained.

[0152] At a flow rate of 5.33 cm / s, the nanofiber composite filtration medium had a filtration efficiency of 99.99% and a pressure drop of 124.2 Pa for NaCl polydisperse aerosols with a median mass of 0.26 μm and a median number of 75 nm. Furthermore, as shown in Figure 9, NaCl polydisperse aerosols with a median mass of 0.26 μm and a median number of 75 nm were continuously added to the composite filtration medium, a PTFE composite filtration medium with a filtration efficiency of 99.95% manufactured by a Japanese company, and an ultrafine glass fiber composite filtration medium with a filtration efficiency of 99.98% manufactured by a US company, and curves were obtained showing the change in pressure drop of the three types of filtration media as a function of load time.

[0153] Its structure is shown in Figure 8. There are four nanofiber layers 1, with 11 being the first nanofiber layer, 12 being the second nanofiber layer, 13 being the third nanofiber layer, and 14 being the fourth nanofiber layer, and there are three inner support layers 2, with 21 being the first micron fiber layer, 22 being the second micron fiber layer, 23 being the third micron fiber layer, 31 being the first outer support layer, and 32 being the second outer support layer.

[0154] [Example 7] A nanofiber air filtration composite media, the preparation method of which comprises the following steps:

[0155] 1. Add a certain polymer to a solvent and stir until completely dissolved to obtain polymer solution A with a mass percent concentration of approximately 12%.

[0156] 2. Using the electrospinning platform, the nanofiber layer was fabricated by electrospinning to a thickness of 0.13 mm and a weight of 20 g / m 2 The nanofiber composite filtration medium is obtained by depositing the nanofiber on a PET spunbond nonwoven fabric substrate.

[0157] 3. Scanning electron microscope images are shown in Figure 10. The minimum fiber diameter of the 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%.

[0158] 4. At a flow rate of 5.33 cm / s, the flow resistance and filtration efficiency of the nanofiber composite filtration medium were measured using 0.3 μm NaCl polydisperse aerosol. The filtration efficiency of the composite filtration medium was 99% and the pressure drop was 70 Pa.

[0159] 5. As shown in Figure 16, polydisperse NaCl aerosol is continuously added to the nanofiber composite filtration medium at a predetermined dust concentration, and a curve showing the change in pressure loss (flow resistance) of the filtration medium depending on the amount of NaCl added is obtained.

[0160] [Example 8] A method for preparing a multi-component nanofiber composite filtration media includes the following steps:

[0161] 1. Add polymer 1 to the solvent and stir until completely dissolved to obtain polymer solution A with a mass percent concentration of approximately 18%.

[0162] 2. Add polymer 2 to the solvent and stir until completely dissolved to obtain polymer solution B with a mass percent concentration of approximately 11%.

[0163] 3. Two nozzle-type electrospinning platforms were prepared, with the nozzle tips facing each other. Solution A was placed on spinning platform #1, and solution B was placed on spinning platform #2. The spinning weight ratio of large-diameter nanofibers to fine nanofibers was approximately 85:15.

[0164] 4. Thickness is 0.13mm, weight per unit area is 20g / m 2 A PET spunbond nonwoven fabric substrate is used to support the nanofiber layer and is coated on top to protect the nanofiber layer (Figure 11). Two electrospinning machines are used for online spinning to prepare multicomponent nanofiber composite filtration media.

[0165] 5. The multicomponent nanofiber composite filtration medium prepared in step 4 was measured using a scanning electron microscope. The SEM image is shown in Figure 12. The ultrafine nanofibers had a minimum fiber diameter of 58.9 nm, a maximum fiber diameter of 243 nm, and an average fiber diameter of 128 nm. The large-diameter nanofibers had a minimum fiber diameter of 793 nm, a maximum fiber diameter of 829 nm, and an average fiber diameter of 811 nm. The expansion rate of the multicomponent nanofiber composite filtration medium was 94%.

[0166] 6. At a flow rate of 5.33 cm / s, the pressure drop and filtration efficiency of the multicomponent nanofiber composite filtration medium prepared in step 4 were measured using 0.33 μm NaCl polydisperse aerosol. Under the same test conditions as in Example 7, when the filtration efficiency reached 99%, the pressure drop of the multicomponent nanofiber composite filtration medium was 50 Pa, a decrease of 28%.

[0167] 7, As shown in Figure 16, NaCl polydisperse aerosol is continuously added to the multicomponent nanofiber composite filtration medium at a predetermined dust concentration, and the curve of the pressure drop of the composite filtration medium changes with the amount of NaCl added is obtained.

[0168] [Example 9] A method for preparing a multi-component nanofiber composite filtration media includes the following steps:

[0169] 1. Polymer 3 is added to the solvent and stirred until completely dissolved, yielding polymer solution C with a mass percentage concentration of approximately 25%.

[0170] 2. Polymer 4 is added to the solvent and stirred until completely dissolved, yielding polymer solution D with a mass percent concentration of approximately 15%.

[0171] 3. Two nozzle-type electrospinning platforms were prepared, with the nozzle tips facing each other. Solution C was placed on spinning platform #1, and solution D was placed on spinning platform #2. The spinning weight ratio of large-diameter nanofibers to fine nanofibers was approximately 80:20.

[0172] 4. Thickness is 0.13mm, weight per unit area is 20g / m 2 The nanofiber layer was supported by a PET spunbond nonwoven fabric substrate, and two electrospinning machines were simultaneously started to spin the nanofibers online to prepare a multi-component nanofiber composite filtration medium.

[0173] 5. The multicomponent nanofiber composite filtration medium prepared in step 4 was measured using a scanning electron microscope. The SEM image is shown in Figure 13. The ultrafine nanofibers had a minimum fiber diameter of 40 nm, a maximum fiber diameter of 160 nm, and an average fiber diameter of 100 nm. The large-diameter nanofibers had a minimum fiber diameter of 1.1 μm, a maximum fiber diameter of 1.9 μm, and an average fiber diameter of 1.5 μm. The expansion rate of the multicomponent nanofiber composite filtration medium was 93%.

[0174] 6. At a flow rate of 5.33 cm / s, a test is conducted to measure the pressure drop and filtration efficiency of the multicomponent nanofiber composite filtration medium prepared in step 4 using 0.33 μm NaCl polydisperse aerosol. Under the same test conditions as in Example 7, when the filtration efficiency reaches 99%, the pressure drop of the multicomponent nanofiber composite filtration medium is 42 Pa.

[0175] 7. As shown in Figure 16, NaCl polydisperse aerosol is continuously added to the multi-component nanofiber composite filtration medium under a predetermined dust concentration, and the curve of the pressure drop of the composite filtration medium changes with the amount of NaCl added is obtained.

[0176] A method for preparing a multi-component nanofiber composite filtration media includes the following steps:

[0177] 1. Polymer 3 is added to the solvent and stirred until completely dissolved, yielding polymer solution E with a mass percent concentration of approximately 20%.

[0178] 2. Polymer 4 is added to the solvent and stirred until completely dissolved, yielding polymer solution F with a mass percent concentration of approximately 10%.

[0179] 3. Prepare two nozzle-type electrospinning platforms, with the nozzle tips facing each other. Place solution E on spinning platform #1 and solution F on spinning platform #2. The weight ratio of large nanofibers to fine nanofibers is approximately 60:40.

[0180] 4. Thickness is 0.13mm, weight per unit area is 20g / m 2 A PET spunbond nonwoven fabric substrate is used to support the nanofiber layer, and two electrospinning machines are activated to spin the nanofibers online to prepare a multi-component nanofiber composite filtration medium.

[0181] 5. The multicomponent nanofiber composite filtration medium prepared in step 4 was measured using a scanning electron microscope. The SEM image is shown in Figure 15. The ultrafine nanofibers had a minimum fiber diameter of 48 nm, a maximum fiber diameter of 140 nm, and an average fiber diameter of 90 nm. The large-diameter nanofibers had a minimum fiber diameter of 1.5 μm, a maximum fiber diameter of 2.2 μm, and an average fiber diameter of 1.85 μm. The expansion rate of the multicomponent nanofiber composite filtration medium was 91%.

[0182] 6. At a flow rate of 5.33 cm / s, a test is conducted to measure the pressure drop and filtration efficiency of the multicomponent nanofiber composite filtration medium prepared in step 4 using 0.3 μm NaCl polydisperse aerosol. Under the same test conditions as in Example 7, when the filtration efficiency reaches 99%, the pressure drop of the multicomponent nanofiber composite filtration medium is 37 Pa.

[0183] 7, as shown in Figure 16, NaCl polydisperse aerosol is continuously added to the multicomponent nanofiber composite filtration medium at a predetermined dust concentration, and the curve of pressure drop changes with the amount of NaCl added is obtained.

[0184] [Example 10] A method for preparing a multi-component nanofiber composite filtration media includes the following steps:

[0185] 1. Weight per unit area is approximately 20g / m 2 A pressure-sensitive adhesive (PSA) was sprayed online onto a PET spunbond nonwoven fabric substrate 2A with a thickness of approximately 0.12 mm, and the amount of PSA used was 2.5 g / m 2 Before the PSA was cured, large-diameter nanofibers and ultrafine nanofibers were simultaneously deposited on a PET spunbond nonwoven fabric substrate by electrospinning to obtain a nanofiber-spunbond nonwoven fabric substrate composite filtration medium with filtration efficiencies of 80% and 95%, respectively. The weight ratio of the large-diameter nanofibers to the fine nanofibers was 75:25.

[0186] The weight per unit area is 35g / m 2 The pressure-sensitive adhesive PSA was sprayed online onto a 0.16 mm thick PET spunbond nonwoven fabric substrate 2A, with a PSA coating weight of 2.5 g / m. 2 Before the PSA was cured, large-diameter nanofibers and ultrafine nanofibers were simultaneously deposited on a PET spunbond nonwoven fabric substrate by electrospinning, resulting in a nanofiber-spunbond nonwoven fabric substrate composite filtration medium with a filtration efficiency of 99%. The weight ratio of the large-diameter nanofibers to the fine nanofibers was 60:40.

[0187] 2. Thickness is 0.16mm, weight per unit area is 35g / m 2 The pressure-sensitive adhesive PSA was sprayed online onto the underside of the PET spunbond nonwoven fabric substrate at a coating weight of approximately 2.5 g / m 2 Next, the PET spunbond nonwoven fabric substrate, the composite filtration medium with a filtration efficiency of 80% prepared in step 1, and the composite filtration medium with a filtration efficiency of 95% (the weight per unit area of ​​the support layer is 20 g / m 2 , thickness 0.12 mm), filtration efficiency 99% composite filtration media (weight per unit area of ​​its support layer is 35 g / m 2 The nanofiber layers (0.16 mm thick) were arranged from top to bottom, with each layer sandwiched between two adjacent spunbond nonwoven fabric substrates. The aligned composite filtration media was subjected to a composite treatment using heat-pressing rolls at a temperature of 140°C with a roll gap of 0.4 mm, resulting in a composite filtration media with high filtration efficiency and low pressure loss. The structural schematic is shown in Figure 17.

[0188] At a flow rate of 5.33 cm / s, the nanofiber composite filtration medium has a filtration efficiency of 99.99% and a pressure drop of 110 Pa for NaCl polydisperse aerosols with a mass median of 0.26 μm and a quantity median of 75 nm. As shown in Figure 18, cigarette smoke was continuously injected into the composite filtration medium and a PTFE membrane composite filtration medium manufactured by a Japanese company with a filtration efficiency of 99.95% at a predetermined concentration and air flow rate, and a curve showing the change in pressure drop (flow resistance) of the two filtration media over time was obtained.

[0189] [Example 11] The composite filtration medium consists of a needle-punched tribo-electrically charged nonwoven fabric, activated carbon, PVDF nanofibers, and a PET nonwoven fabric substrate. The weight per unit area of ​​the needle-punched tribo-electrically charged nonwoven fabric is 47.5 g / m. 2 The thickness is 0.504 mm, the flow resistance is 4.63 Pa when the air flow velocity is 16.7 cm / s, and the filtration efficiency is 39.81% when the air flow velocity is 26.25 cm / s. The weight per unit area of ​​the PET drylaid nonwoven fabric substrate is 70 g / m 2The thickness was 0.38 mm, the tensile strength was 160 N / 5 cm (machine direction (MD)) and 60 N / 5 cm (cross direction (CD)), the flow resistance was 0.75 Pa, and the filtration efficiency was 5.82% at an air flow rate of 32 L / min. PVDF nanofibers with a diameter of 0.14 μm (observed by scanning electron microscope), a flow resistance of 4.15 Pa, and a filtration efficiency of 55.36% (flow rate of 32 L / min) were spun onto a PET nonwoven fabric substrate using the electrospinning method.

[0190] The activated carbon had a mesh size of 30-60, an iodine value of 1000, a hardness of 98, and an ash content of 5%. The PVDF nanofibers were attached to a dry PET substrate and coated with an adhesive and activated carbon (180 g / m). 2 ) and composite treatment with the needle-punched tribo-electrically charged nonwoven fabric. The filtration medium prepared in this way is designated NF-1, and the sum of the weights per unit area is 319 g / m 2 , thickness is 1.32 mm, and when the air flow velocity is 16.7 cm / s, the filtration efficiency is 72.2%, the flow resistance is 27 Pa, and the dust holding capacity is 80.64 g / m 2 Compared with Example 21 below, the flow resistance is almost the same, but the filtration efficiency is 36% higher and the dust holding capacity is 101% higher.

[0191] [Example 12] The composite filtration medium consists of a needle-punched tribo-electrically charged nonwoven fabric, activated carbon, polyamide nanofibers, and a PET nonwoven fabric substrate. The weight per unit area of ​​the needle-punched tribo-electrically charged nonwoven fabric is 38.4 g / m. 2 The thickness is 0.398 mm, the flow resistance is 3.8 Pa, and the filtration efficiency is 38.4% when the air flow rate is 16.7 cm / s. The weight per unit area of ​​the PET nonwoven fabric substrate is 70 g / m 2 The thickness is 0.38 mm, the tensile strength is 160 N / 5 cm (vertical direction) and 60 N / 5 cm (horizontal direction), the flow resistance is 0.75 Pa, and the filtration efficiency at an air flow rate of 32 L / min is 5.82%. Using electrospinning, polyamide nanofibers with a diameter of 0.1 μm (observed with a scanning electron microscope), a flow resistance of 4.15 Pa, and a filtration efficiency of 55.36% at an air flow rate of 32 L / min are spun onto a PET nonwoven fabric substrate. The activated carbon has a 30-60 mesh, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0192] When prepared, polyamide nanofibers were attached to a PET nonwoven substrate and coated with adhesive and activated carbon (90 g / m 2 ) and composite treatment with needle punch tribo-charged filtration media. The composite filtration media obtained in this way is designated as NF-2, and the total weight per unit area is 261 g / m 2 , thickness 1.32 mm, flow resistance 21.55 Pa, filtration efficiency 63.72% (flow velocity 16.7 cm / s), dust retention capacity 63.61 g / m 2 (Flow velocity: 0.3 m / s) Compared with Example 22 below, the flow resistance is 36% lower, the filtration efficiency is almost the same, but the dust retention capacity is 57% higher.

[0193] [Example 13] The composite filtration medium is composed of meltblown nonwoven fabric, activated carbon, PAN nanofiber, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 16.5g / m. 2 The thickness is 0.167 mm, the flow resistance is 6.77 Pa, and the filtration efficiency is 42.8% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 50 g / m 2 The thickness is 0.38 mm, the tensile strength is 80 N / 5 cm (longitudinal direction) and 60 N / 5 cm (transverse direction), the flow resistance is 0.75 Pa, and the filtration efficiency is 5.82% at an air flow rate of 32 L / min. PAN nanofibers with a diameter of 0.2 μm (observed with a scanning electron microscope), a flow resistance of 2.7 Pa, and a filtration efficiency of 33.5% (flow rate: 32 L / min) are spun onto a PET nonwoven fabric substrate using electrospinning. The activated carbon has a 60-80 mesh, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0194] When prepared, PAN nanofibers were attached to a PET nonwoven substrate and coated with adhesive and activated carbon (90 g / m 2 ) and composite treatment with meltblown nonwoven fabric. The total weight per unit area of ​​the composite filtration medium obtained in this way is 180 g / m 2 , thickness is 0.818 mm, flow resistance is 17.7 Pa, filtration efficiency is 66.35% (flow velocity 16.7 cm / s), dust retention capacity is 19.77 g / m2 Compared with the following Example 23, the flow resistance and dust holding capacity are almost the same, but the filtration efficiency is 73.7% higher.

[0195] [Example 14] The composite filtration medium is composed of meltblown nonwoven fabric, activated carbon, PS nanofiber, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 16.5g / m. 2 The thickness is 0.167 mm, the flow resistance is 4.3 Pa, and the filtration efficiency is 27.23% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 50 g / m 2 The thickness is 0.30 mm, the tensile strength is 80 N / 5 cm (vertical direction) and 60 N / 5 cm (horizontal direction), the flow resistance is 0.75 Pa, and the filtration efficiency is 5.82% (flow rate: 32 L / min). Using electrospinning, PS nanofibers with an average diameter of 0.25 μm (observed with an electron microscope), flow resistance of 3.9 Pa, and filtration efficiency of 46.1% (flow rate 5.33 cm / s) are spun onto a PET nonwoven fabric substrate. The activated carbon has a 60-80 mesh, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0196] When prepared, PS nanofibers were attached to a PET nonwoven substrate and coated with adhesive and activated carbon (180 g / m 2 ) and composite treatment with meltblown nonwoven fabric. The composite filter medium obtained in this way is designated as NF-4, and the sum of the weight per unit area is 270 g / m 2 , thickness 0.823 mm, flow resistance 21.6 Pa, filtration efficiency 69.13% (flow velocity 16.7 cm / s), dust retention capacity 19.49 g / m 2 Compared with the following Example 23, the flow resistance is 30% higher, the filtration efficiency is 81.6% higher, and the dust holding capacity is almost the same.

[0197] [Example 15] The composite filtration medium is composed of meltblown nonwoven fabric, activated carbon, PVDF nanofiber, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 14.6g / m. 2The thickness is 0.19 mm, the flow resistance is 2.7 Pa, and the filtration efficiency is 10.37% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 70 g / m 2 The thickness is 0.38 mm, the tensile strength is 160 N / 5 cm (vertical direction) and 60 N / 5 cm (horizontal direction), the flow resistance is 0.75 Pa, and the filtration efficiency is 5.82% (flow rate: 5.33 cm / s). PVDF nanofibers with a diameter of 0.1 μm (observed with a scanning electron microscope), a flow resistance of 3.6 Pa, and a filtration efficiency of 58.7% (flow rate: 32 L / min) are electrospun onto a PET nonwoven fabric substrate. The activated carbon has a 30-60 mesh, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0198] When prepared, PVDF nanofibers were attached to a PET nonwoven substrate and coated with adhesive and activated carbon (90 g / m 2 ) and composited with meltblown nonwoven fabric. The composite filter media obtained in this way is designated as NF-5, and the total weight per unit area is 165 g / m 2 , thickness 0.9 mm, flow resistance 10.7 Pa, filtration efficiency 40.16% (flow velocity 16.7 cm / s), dust retention capacity 19.93 g / m 2 Compared with Comparative Example 3, the flow resistance is 22.7% lower, and the filtration efficiency and dust holding capacity are almost the same.

[0199] [Example 16] The composite filtration medium is composed of meltblown nonwoven fabric, activated carbon, PVDF nanofiber, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 10.4g / m. 2 The thickness is 0.18 mm, the flow resistance is 8.6 Pa, and the filtration efficiency is 25.76% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 70 g / m 2The thickness is 0.38 mm, the tensile strength is 160 N / 5 cm (vertical direction) and 60 N / 5 cm (horizontal direction), the flow resistance is 0.75 Pa, and the filtration efficiency is 5.82% (flow rate: 5.33 cm / s). PVDF nanofibers are electrospun onto a PET nonwoven fabric substrate using a 0.18 μm diameter (observed with a scanning electron microscope), the flow resistance is 3.9 Pa, and the filtration efficiency is 62.4% (flow rate: 32 L / min). The activated carbon has a 30-60 mesh, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0200] When prepared, PVDF nanofibers were attached to a PET substrate and coated with adhesive and activated carbon (90 g / m 2 ) and composited with meltblown nonwoven fabric. The composite filter media obtained in this way is designated as NF-6, and the total weight per unit area is 175.4 g / m 2 , thickness is 0.568 mm, flow resistance is 17.6 Pa, filtration efficiency is 44.45% (flow velocity 16.7 cm / s), dust retention capacity is 11.7 g / m 2 Compared with Comparative Example 4, the flow resistance is 12.2% lower, the filtration efficiency is almost the same, and the dust retention capacity is 117% higher.

[0201] [Example 17] The composite filtration medium is composed of meltblown nonwoven fabric, activated carbon, TPU nanofiber, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 10.4g / m. 2 The thickness is 0.18 mm, the flow resistance is 8.6 Pa, and the filtration efficiency is 25.76% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET substrate is 70 g / m 2 The TPU nanofibers were electrospun onto a PET nonwoven fabric substrate, with a diameter of 0.1 μm (observed with a scanning electron microscope), a flow resistance of 3.6 Pa, and a filtration efficiency of 58.7% (flow rate: 32 L / min). The activated carbon had a 30-60 mesh sieve, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0202] When prepared, TPU nanofibers were attached to a PET nonwoven substrate and coated with adhesive and activated carbon (90 g / m 2 ) and composited with meltblown nonwoven fabric. The composite filter media obtained in this way is designated as NF-7, and the total weight per unit area is 175.4 g / m 2 , thickness 0.568mm, flow resistance 20.85Pa, filtration efficiency 56.22% (flow velocity 16.7cm / s), dust retention capacity 11.6g / m 2 Compared with Comparative Example 5, the flow resistance is 35.4% lower, the filtration efficiency is almost the same, and the dust retention capacity is 93% higher.

[0203] [Example 18] The composite filtration medium is composed of meltblown nonwoven fabric, activated carbon, PAN nanofiber, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 19.7g / m. 2 The thickness is 0.13 mm, the flow resistance is 4.3 Pa, and the filtration efficiency is 16.54% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET substrate is 70 g / m 2 The thickness is 0.38 mm, the tensile strength is 160 N / 5 cm (vertical direction) and 60 N / 5 cm (horizontal direction), the flow resistance is 0.75 Pa, and the filtration efficiency is 5.82% (flow rate: 5.33 cm / s). PAN nanofibers with a diameter of 0.15 μm (observed with a scanning electron microscope), a flow resistance of 3.9 Pa, and a filtration efficiency of 62.4% (flow rate: 32 L / min) are electrospun onto a PET nonwoven fabric substrate. The activated carbon has a 30-60 mesh, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0204] When prepared, PAN nanofibers were attached to a PET nonwoven substrate and coated with adhesive and activated carbon (90 g / m 2 ) and composite treatment with meltblown nonwoven fabric. The composite filter medium obtained in this way is designated as NF-8, and the total weight per unit area is 184.7 g / m 2 , thickness is 0.518 mm, flow resistance is 12.4 Pa, filtration efficiency is 42.31% (flow velocity 16.7 cm / s), dust retention capacity is 11.5 g / m 2Compared with Comparative Example 4, the flow resistance is 38.2% lower, the filtration efficiency is almost the same, and the dust retention capacity is 113% higher.

[0205] [Example 19] The composite filtration media consists of meltblown nonwoven fabric, activated carbon, TPU nanofiber, and a PET substrate. The weight of the meltblown nonwoven fabric per unit area is 19.7g / m. 2 The thickness is 0.13 mm, the flow resistance is 4.3 Pa, and the filtration efficiency is 16.54% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 70 g / m 2 The TPU nanofibers were electrospun to a thickness of 0.38 mm, tensile strength of 160 N / 5 cm (vertical direction) and 60 N / 5 cm (horizontal direction), flow resistance of 0.75 Pa, and filtration efficiency of 5.82% (flow rate: 5.33 cm / s). The TPU nanofibers were sprayed onto a PET nonwoven fabric substrate using an electrospinning method. The diameter was 0.15 μm (observed using a scanning electron microscope), flow resistance was 3.6 Pa, and filtration efficiency was 58.7% (flow rate: 32 L / min). The activated carbon had a 30-60 mesh sieve, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0206] When prepared, TPU nanofibers were attached to a PET nonwoven substrate and coated with adhesive and activated carbon (90 g / m 2 ) and composite treatment with meltblown nonwoven fabric. The resulting composite filter medium is designated as NF-9, and the total weight per unit area is 184.7 g / m 2 , thickness is 0.518 mm, flow resistance is 17.2 Pa, filtration efficiency is 50.49% (flow velocity 16.7 cm / s), dust retention capacity is 10.7 g / m 2 Compared with Comparative Example 5, the flow resistance is 46.7% lower, the filtration efficiency is almost the same, and the dust retention capacity is 78% higher.

[0207] [Example 20] The composite filtration medium is composed of meltblown nonwoven fabric, activated carbon, PA nanofiber, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 14.6 g / m. 2The thickness is 0.19 mm, the flow resistance is 2.7 Pa, and the filtration efficiency is 10.37% (flow velocity is 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 50 g / m 2 The PA nanofibers were electrospun onto a PET nonwoven fabric substrate using a 0.30mm thickness, 80N / 5cm tensile strength (longitudinal), 60N / 5cm tensile strength (transverse), 0.75Pa flow resistance, and 5.82% filtration efficiency at a flow rate of 32L / min. The PA nanofibers had an average diameter of 0.1μm (observed using a scanning electron microscope), a flow resistance of 3.9Pa, and a filtration efficiency of 62.4% at a flow rate of 32L / min. The activated carbon had a 30-60 mesh sieve, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0208] When preparing the composite media, PA nanofibers were attached to a PET substrate, and then the substrate was sprayed with a layer of adhesive before being coated with 90 g / m 2 Activated carbon particles are then sprayed onto the activated carbon layer, and another layer of adhesive is sprayed onto the activated carbon layer, and finally, the layer is composited with a meltblown nonwoven fabric layer.

[0209] The composite filter medium thus obtained is designated as NF-10, and the sum of the weights per unit area is 179.6 g / m 2 , thickness is 0.578 mm, flow resistance is 9.35 Pa, filtration efficiency is 35.48% (flow velocity 16.7 cm / s), ASHRAE dust holding capacity is 14.9 g / m 2 Compared with Comparative Example 5, the flow resistance is 53.4% ​​lower, the filtration efficiency is 17% lower, and the dust retention capacity is 176% higher.

[0210] [Comparative Example 21] Comparative Example 21 is designated as NFR-1, and the composite filtration medium is 20 g / m 2 PET nonwoven fabric and 18g / m 2 meltblown nonwoven fabric and 205g / m 2 of activated carbon and 70g / m 2 and a PET nonwoven fabric support layer, each layer being bonded with an adhesive, with the sum of the weights per unit area being 340 g / m 2 , thickness is 1.1 mm, flow resistance is 28.3 Pa, filtration efficiency is 52% (flow velocity 0.167 m / s), dust retention capacity is 40 g / m 2(flow velocity 0.3 m / s).

[0211] [Comparative Example 22] Comparative Example 22 is designated as NFR-2 and has a composite filtration medium of 20 g / m 2 PET nonwoven fabric and 25g / m 2 meltblown nonwoven fabric and 340g / m 2 of activated carbon and 70g / m 2 and a PET nonwoven fabric support layer, each layer being bonded with an adhesive, with the sum of the weights per unit area being 485 g / m 2 , thickness is 1.4 mm, flow resistance is 33.4 Pa, filtration efficiency is 58% (flow velocity 0.167 m / s), dust retention capacity is 40 g / m 2 (flow velocity 0.3 m / s).

[0212] [Comparative Example 23] Comparative Example 23 is designated as NFR-3, and the upper layer of the composite filtration medium is 18 g / m 2 meltblown layer, middle layer is 60g / m 2 activated carbon particles, the bottom layer is 50g / m 2 The total weight per unit area is 165g / m 2 , thickness is 0.5435 mm, flow resistance is 13.8 Pa, filtration efficiency is 38.26% (flow velocity 16.7 cm / s), dust retention capacity is 20.32 g / m 2 is.

[0213] [Comparative Example 24] The composite filtration medium of Comparative Example 24 is composed of a meltblown nonwoven fabric, activated carbon, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 14.6 g / m 2 The thickness is 0.12 mm, the flow resistance is 15.7 Pa, and the filtration efficiency is 36.79% (flow rate 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 70 g / m 2 The thickness is 0.38mm, the tensile strength is 160N / 5cm (vertical direction) and 60N / 5cm (horizontal direction), the flow resistance is 0.75Pa, and the filtration efficiency is 5.82% (flow rate 32L / min). The activated carbon has a 30-60 mesh, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0214] When preparing the adhesive, a PET nonwoven fabric substrate and activated carbon (90 g / m 2 ) and composited with meltblown nonwoven fabric. The composite filter medium obtained in this way is designated as NFR-4, and the total weight per unit area is 179.6 g / m 2 , thickness 0.508mm, flow resistance 20.05Pa, filtration efficiency 42.74% (flow velocity 16.7cm / s), dust retention capacity 5.4g / m 2 is.

[0215] [Comparative Example 25] The composite filtration medium of Comparative Example 25 is composed of a meltblown nonwoven fabric, activated carbon, and a PET nonwoven fabric substrate. The weight per unit area of ​​the meltblown nonwoven fabric is 16.3 g / m 2 The thickness is 0.18 mm, the flow resistance is 18 Pa, and the filtration efficiency is 44.78% (flow velocity 16.7 cm / s). The weight per unit area of ​​the PET nonwoven fabric substrate is 70 g / m 2 The thickness is 0.38 mm, the tensile strength is 160 N / 5 cm (vertical direction) and 60 N / 5 cm (horizontal direction), the flow resistance is 0.75 Pa, and the filtration efficiency is 5.82% (flow rate 32 L / min). The activated carbon has a mesh size of 60-80, an iodine value of 1000, a hardness of 98, and an ash content of 5%.

[0216] When preparing the adhesive, the PET substrate was coated with adhesive and activated carbon (90 g / m 2 ) and composited with meltblown nonwoven fabric. The composite filter media obtained in this way is designated as NFR-5, and its total weight per unit area is 181.3 g / m 2 , thickness 0.568mm, flow resistance 32.3Pa, filtration efficiency 53.89% (flow velocity 16.7cm / s), dust retention capacity 6.0g / m 2 is.

[0217] Nanofiber composite filtration media can use highly breathable substrates, reducing overall flow resistance and being energy-saving and environmentally friendly. Experimental results show that the activated carbon leakage rate of filtration media with nanofiber coated substrates is significantly lower than that of filtration media without nanofiber coated substrates. The test conditions are shown in the table below. [Table 1]

[0218] As can be seen from the above, nanofiber composite filtration media can use fine particulate activated carbon, which has a larger surface area and better adsorption performance. The use of fine particulate activated carbon reduces the thickness of the composite filtration media, allowing the filter element to accommodate more composite filtration media. A larger surface area of ​​the filtration media reduces the flow resistance of the filter element and extends its service life. Furthermore, a thinner filtration media is more advantageous in the design and manufacture of filter elements.

[0219] In at least one embodiment, the design of the air filtration media containing nanofibers satisfies the following criteria:

[0220] 1. The diameter of nanofibers is less than 1 μm (0.3 μm).

[0221] 2. The breathability of the base material is over 800L / min (2000L / min).

[0222] 3. The filtration efficiency of nanofibers is 10-95%.

[0223] In at least one embodiment, the nanofiber-containing air filtration media design includes activated carbon with a particle size of 30-100 mesh.

[0224] In at least one embodiment, the nanofiber-containing air filtration media is designed to have an efficiency of 95-99.95%, a flow resistance of 25-100 Pa at a flow velocity of 16.7 cm / s, and a dust holding capacity of 10-100 g / m. 2 (The final pressure is twice the initial pressure drop.)

[0225] In at least one embodiment, the nanofibers can be prepared by blending a polymeric material dissolved in a solvent with a functional and / or charge additive, where the polymer can be selected from polyamide (Nylon), PVDF (Polyvinylidene Fluoride), PAN (Polyacrylonitrile), PES (Polyethersulfone), TPU (Thermoplastic Polyurethane), or PS (Polystyrene), the solvent can be selected from formic acid, DMAC (Dimethylacetamide), or DMF (Dimethylformamide), and the additive can be LiCl (Lithium Chloride), KCl (Potassium Chloride), or an antimicrobial agent.

[0226] In at least one embodiment, the solution is formed into nanofibers by electrospinning using the following parameters: voltage 10-70 kv, DCD 10-30 cm, flow rate 0.01-0.1 ml / min / nozzle.

[0227] In at least one embodiment, nanofibers are spun onto a substrate and then compounded with activated carbon, meltblown, tribocharging media, or other electrostatically charged materials, which can be achieved by adhesive spray, powder adhesive, or film transfer adhesive techniques.

[0228] In at least one embodiment, the nanofibers and / or other components provide antibacterial and antiviral functionality and VC-releasing functionality, and in some embodiments, nanocomposites containing nanofibers provide enhanced functional properties.

[0229] The nanofiber composite filtration media described herein can be used in a variety of filtration applications. For example, FIG. 25 shows a pleated filter element 2500. In one embodiment, the pleated filter element can be used in an automobile or other mobile vehicle. The pleated filter element 2500 includes a filtration media pack 2502 of pleated filtration media 2504 mounted within a frame 2506. As shown, the outer shape is rectangular, although it is not intended to be so limited.

[0230] 26 shows another filtration product using a nanofiber composite filtration media according to the invention. A multi-V element 2600 includes a plurality of pleated regions 2602 arranged on a frame 2604. The frame 2604 is provided with a plurality of inlets 2606 for receiving filtration media pleats 2608. The filtration media pleats 2608 include a nanofiber composite filtration media according to the invention.

[0231] 27 shows another filtration product 2700 that utilizes a nanofiber composite filtration media described herein. It includes a media pack 2702 that is pleated and can include a nanofiber composite filtration media described herein. Filtration product 2700 includes an upstream side 2704 and a downstream side 2706.

[0232] In some embodiments, the nanofiber composite filtration media can be used for air purification, cabin air filtration, HVAC filtration, liquid filtration, and the like.

[0233] To better illustrate the media, methods and apparatus disclosed herein, a non-limiting list of examples is provided herein.

[0234] Form 1. 1. A composite filtration medium comprising: a first nanofiber layer; a second nanofiber layer; an inner support layer disposed between the first and second nanofiber layers; wherein the inner support layer serves to support, isolate and space the first and second nanofiber layers, reducing the packing density of the nanofiber layers; the first nanofiber layer contains nanofibers having a diameter of 1 nm to 5000 nm; The inner support layer has an average fiber diameter of less than 100 μm.

[0235] Form 2. The first nanofiber layer contains nanofibers having an average fiber diameter of 10 nm to 5000 nm, 2. The composite filtration media of claim 1, wherein the inner support layer has an average fiber diameter of less than 30 μm.

[0236] Form 3. The weight per unit area of ​​the inner support layer is 80g / m 2 is less than 2. The composite filtration media of claim 1, wherein the inner support layer comprises any one or combination of a spunbond nonwoven, a dry-laid nonwoven, a wet-laid nonwoven, a meltblown nonwoven, and a fiber mesh.

[0237] Form 4. 4. The composite filtration media of claim 3, wherein the difference in particle filtration efficiency between the downstream nanofiber layer and the adjacent upstream nanofiber layer is less than 60%.

[0238] Form 5. Contains a single-component nanofiber layer or multi-component nanofibers (a mixture of large and small size fibers), wherein the large size fibers are in the range of 100 to 5000 nm, preferably greater than 200 nm, more preferably greater than 300 nm; the small size fibers are in the range of 10 to 500 nm, preferably less than 200 nm, more preferably less than 150 nm; and the weight ratio of the large size fibers to the small size fibers is 10:90 to 99:1.

[0239] Form 6. Large size fibers are in the range of 200-5000 nm. Small size fibers are in the range of 10-200 nm, 5. The composite filtration medium according to any one of embodiments 1 to 4, wherein the mass ratio of the large size fibers to the small size fibers is 40:60 to 90:10.

[0240] Form 7. the nanofiber layer comprises submicron fibers and micron fibers; the nanofiber layer has a unimodal average fiber diameter distribution (with a peak within the nanofiber diameter range); or exhibiting a bimodal / multimodal distribution (one peak in the nanofiber diameter range and another peak in the submicron / micron fiber diameter range).

[0241] Form 8. an upper outer support layer disposed above the upper nanofiber layer; and / or a bottom outer support layer disposed below the bottom nanofiber layer; 10. The composite filtration medium of claim 1, wherein the outer support layer provides strength and / or rigidity to the composite filtration medium.

[0242] Form 9. an outer support layer disposed below the bottom nanofiber layer is a first outer support layer; 9. The composite filtration media of claim 8, wherein the outer support layer disposed above the upper nanofiber layer is a second outer support layer.

[0243] Form 10. 2. The composite filtration medium of claim 1, wherein the material of the nanofibers comprises any one of polymers or inorganic materials selected from the group consisting of PA6 (polyamide 6), PA56 (polyamide 56), PA66 (polyamide 66), PA1010 (polyamide 1010), PAN (polyacrylonitrile), PLA (polylactic acid), PU (polyurethane), PVDF (polyvinylidene fluoride), PS (polystyrene), PEI (polyetherimide), PMIA (poly(m-phenylene isophthalamide)), Al2O3 (alumina), SiO2 (silica), ZrO2 (zirconia), or any combination thereof.

[0244] Form 11. 2. The composite filtration medium of claim 1, wherein the nanofibers are continuous or discontinuous fibers.

[0245] Form 12. 2. The composite filtration medium of claim 1, wherein the material of the inner support layer is any one of PP (polypropylene), PET (polyethylene terephthalate), PE (polyethylene), PA (polyamide), PVDF (polyvinylidene fluoride), PAN (polyacrylonitrile), PS (polystyrene), PET / PE, PET / low melting point PET (PET / LMPET), PLA (polylactic acid), and glass fiber, or any combination thereof.

[0246] Form 13. 2. The composite filtration medium according to claim 1, wherein when the inner support layer comprises a two-component polymer, the weight ratio of the surface layer polymer to the core layer polymer is 30 / 70 to 70 / 30, or 20 / 80 to 80 / 20, or 10 / 90 to 90 / 10.

[0247] Form 14. 2. The composite filtration medium according to claim 1, wherein the inner support layer (2) has an average diameter of 0.3 μm to 100 μm.

[0248] Form 15. 2. The composite filtration medium of claim 1, wherein the inner support layer has an average diameter of 0.5 to 6 μm.

[0249] Form 16. 2. The composite filtration medium of claim 1, wherein the inner support layer has an average diameter of 7 to 25 μm.

[0250] Form 17. 2. The composite filtration media of claim 1, wherein the outer support layer (3) is selected from a spunbond nonwoven, an airlaid nonwoven, a drylaid nonwoven, a wetlaid nonwoven, a meltblown nonwoven, and any combination thereof.

[0251] Form 18. 5. The composite filtration medium of any one of claims 1 to 4, wherein the nanofiber layer further comprises submicron fibers and micron fibers having a fiber diameter of ≦60 μm.

[0252] Form 19. 19. The composite filtration medium of claim 18, wherein the submicron and micron fibers are uniformly distributed short fibers and / or continuous filaments and are made of polymer or inorganic material.

[0253] Form 20. 19. The composite filtration media of claim 18, wherein the submicron and micron fibers comprise any one or combination of PA6 (polyamide 6), PA56 (polyamide 56), PA66 (polyamide 66), PA1010 (polyamide 1010), PAN (polyacrylonitrile), PLA (polylactic acid), PU (polyurethane), PES (polyethersulfone), PBT (polybutylene terephthalate), PC (polycarbonate), PVDF (polyvinylidene fluoride), PI (polyimide), PMIA (poly(m-phenylene isophthalamide)), PTFE (polytetrafluoroethylene), Al2O3 (alumina), SiO2 (silica), ZrO2 (zirconia), PP (polypropylene), PE (polyethylene), PET (polyethylene terephthalate), PET / PE, PET / low melting point PET (PET / LMPET), and glass fibers.

[0254] Form 21. 2. The composite filtration medium of aspect 1, wherein in the nanofiber layer, the nanofibers to micron and / or submicron fibers have a quantitative ratio of 1:6 to 600:1 and a weight ratio of 1:99 to 10:1.

[0255] Form 22. 1. A method for preparing a composite filtration medium, comprising: S1 and S2, wherein: S1. Forming a nanofiber layer (1) on the inner support layer (2) and the first outer support layer (31) by electrospinning, the nanofiber layer (1) containing nanofibers with a diameter of 1 nm to 5000 nm; The inner support layer (2) is selected from any one of spunbond nonwoven fabrics, dry-laid nonwoven fabrics, wet-laid nonwoven fabrics, melt-blown nonwoven fabrics, and fiber meshes, each having a diameter of less than 100 μm, or a combination thereof. S2. An optional second outer support layer (32) is placed on top of the nanofiber layer (1), the second outer support layer having a protective, dust-retaining or efficiency-enhancing function; The nanofiber layer (2), inner support layer (2) and outer support layer (3) are subjected to a compounding treatment by thermocompression compounding, adhesive bonding compounding, ultrasonic compounding or a combination thereof to obtain the composite filtration medium.

[0256] Form 23. 1. A method for preparing a composite filtration medium, comprising: S1 and S2, wherein: S1. Electrospinning a first nanofiber layer onto an inner support layer and electrospinning a second nanofiber layer onto a first outer support layer; A composite filtration media unit is formed comprising a first nanofiber layer, an inner support layer, a second nanofiber layer, and a first outer support layer, the first and second nanofiber layers contain nanofibers having a diameter of 1 nm to 5000 nm; The inner support layer is selected from any one of spunbond nonwoven fabrics, dry-laid nonwoven fabrics, wet-laid nonwoven fabrics, melt-blown nonwoven fabrics, and fiber meshes, each having a fiber diameter of less than 100 μm, or any combination thereof. S2. disposing a second outer support layer, protective layer, or dust-retaining layer above the first nanofiber layer; The first nanofiber layer, inner support layer, and outer support layer are combined by thermocompression bonding, adhesive bonding, and / or ultrasonic bonding to form a composite filtration media.

[0257] Form 24. In step S1, The inner support layer (2) is at least one layer, and the thickness and weight per unit area of ​​each inner support layer may be different. The first outer support layer (31) has a weight per unit area of ​​80 g / m 2 (gsm) or less, can be selected from any one or any combination of spunbond nonwoven fabric, dry-laid nonwoven fabric, wet-laid nonwoven fabric, meltblown nonwoven fabric or web, 24. The method of any one of claims 22 to 23, wherein the optional second outer support layer (32) is

[0258] Form 25. 24. The method of claim 22 or 23, wherein the number of inner support layers in step S1 is at least two, and the thicknesses and weights per unit area of ​​the inner support layers may be different. The first outer support layer and the optional second outer support layer may comprise a spunbond nonwoven, a dry-laid nonwoven, a meltblown nonwoven, or a wet-laid nonwoven or web.

[0259] Form 26. 24. The method of claim 22 or 23, wherein in step S1, nanofibers are deposited on the inner support layer (2) and the first outer support layer (31) by electrospinning to form a nanofiber layer (1), the nanofiber diameter being ≦5 μm, the fiber diameters of the inner support layer (2) and the first outer support layer being 0.5 μm to 100 μm, and the quantity ratio of the nanofibers to the micron and / or submicron fibers is 1:6 to 600:1, and the weight ratio of the nanofibers to the micron and / or submicron fibers is 10:90 to 10:1.

[0260] Form 27. In step S1, the nanofiber layer (1) is formed by depositing nanofibers, micron fibers, and / or submicron fibers simultaneously on the inner support layer (2) and the first outer support layer (31) by electrospinning; the nanofiber diameter is ≦5 μm, and the submicron and micron fiber diameters are ≦100 μm; The fiber diameter of the inner support layer (2) is 0.5 μm to 100 μm, 24. The method of claim 22 or 23, wherein the nanofibers and the micron and / or submicron fibers are present in a quantitative ratio of 2:1 to 600:1 and in a weight ratio of 1:99 to 10:1.

[0261] Form 28. 10. The composite filtration media of any preceding claim, wherein the nanofibers, micron fibers and / or submicron fibers are produced by electrospinning or a combination of electrospinning and other fiber dispersion and web formation methods, such as airlaid, drylaid or aerodynamic web formation.

[0262] Form 29. 10. The composite filtration media of any preceding claim, wherein the nanofiber layer can be 2-99 layers and the inner support layer can be 1-98 layers.

[0263] Form 30. 10. The composite filtration medium of any preceding claim, wherein the nanofiber layer comprises a mixture of lofty nanofibers and finer nanofibers.

[0264] Form 31. 10. The composite filtration media of any preceding claim, wherein the nanofiber filtration media can be composited with activated carbon particles to form an adsorptive composite filtration media.

[0265] Form 32. A composite filtration medium comprising multicomponent nanofibers, at least one of which has a lofty structure and is mixed with other fine nanofibers in the same layer or constructed as a layered structure.

[0266] Form 33. 33. The composite filtration medium according to aspect 32, wherein the nanofibers having a lofty structure have an average diameter of 100 nm to 5 μm, and the fine nanofibers have an average diameter of 10 nm to 300 nm.

[0267] Form 34. The diameter of the lofty nanofibers is greater than 0.1 μm, preferably greater than 0.3 μm, more preferably greater than 0.5 μm; 34. The composite filtration medium of claim 33, wherein the fine nanofibers have a diameter of less than 0.3 μm, preferably less than 0.15 μm.

[0268] Form 35. 35. The composite filtration medium of claim 34, wherein the lofty nanofibers have a loftiness (void volume) of >70%.

[0269] Form 36. 35. The composite filtration medium according to aspect 34, wherein the weight ratio of the nanofibers having a lofty structure to the fine nanofibers is 10:90 to 99:1.

[0270] Form 37. 10. The composite filtration media of any preceding claim, wherein the nanofiber layer can be 2-99 layers and the inner support layer can be 1-98 layers.

[0271] Form 38. The composite filtration medium of any preceding claim, wherein the multi-component nanofiber layer can have a filtration efficiency of 30% to 99.9999995%.

[0272] Form 39. The composite filtration medium according to any one of the preceding claims, having high filtration efficiency and low flow resistance, wherein the filtration efficiency is 60-85% and the flow resistance is 5-20 Pa when tested according to ISO29463-3 or other equivalent standards.

[0273] Form 40. The composite filtration medium according to any one of the preceding claims, which has high filtration efficiency and low flow resistance, and when tested in accordance with ISO29463-3 or other equivalent standards, has a filtration efficiency of 85 to 95% and a flow resistance of 15 to 50 Pa at a flow rate of 5.33 cm / s.

[0274] Form 41. The composite filtration medium according to any one of the preceding claims, having high filtration efficiency and low flow resistance, wherein when tested in accordance with ISO29463-3 or other equivalent standards, the filtration efficiency is 95 to 99.5% and the flow resistance is 30 to 150 Pa at a flow rate of 5.33 cm / s.

[0275] Form 42. The composite filtration medium according to any one of the preceding claims, having high filtration efficiency and low flow resistance, wherein when tested in accordance with ISO29463-3 or other equivalent standards, the filtration efficiency is 99.5 to 99.95% and the flow resistance is 70 to 200 Pa at a flow rate of 5.33 cm / s.

[0276] Form 43. The composite filtration medium according to any one of the preceding claims, having high filtration efficiency and low flow resistance, wherein when tested in accordance with ISO29463-3 or other equivalent standards, the filtration efficiency is 99.95 to 99.995% and the flow resistance is 120 to 230 Pa at a flow rate of 5.33 cm / s.

[0277] Form 44. The composite filtration medium according to any one of the preceding claims, having high filtration efficiency and low flow resistance, wherein when tested in accordance with ISO29463-3 or other equivalent standards, the filtration efficiency is 99.995 to 99.9995% and the flow resistance is 150 to 280 Pa at a flow rate of 5.33 cm / s.

[0278] Form 45. The composite filtration medium according to any one of the preceding claims, having high filtration efficiency and low flow resistance, wherein when tested in accordance with ISO29463-3 or other equivalent standards, the filtration efficiency is 99.9995 to 99.99995% and the flow resistance is 180 to 320 Pa at a flow rate of 5.33 cm / s.

[0279] Form 46. The composite filtration medium according to any one of the preceding claims, having high filtration efficiency and low flow resistance, wherein when tested in accordance with ISO29463-3 or other equivalent standards, the filtration efficiency is 99.99995 to 99.999995% and the flow resistance is 250 to 400 Pa at a flow rate of 5.33 cm / s.

[0280] Form 47. 1. A composite filtration medium comprising: at least one support layer; and at least one multicomponent nanofiber layer; The multi-component nanofiber layer includes nanofibers having a lofty structure and fine nanofibers.

[0281] Form 48. 48. The composite filtration medium of claim 47, wherein nanofiber layers with the same or different filtration efficiencies are composited by thermocompression composite, adhesive bonding composite, and / or ultrasonic composite methods to meet specific application needs.

[0282] Form 49. 48. The composite filtration medium of claim 47, wherein the lofty nanofibers and fine nanofibers are prepared by nozzle electrospinning, nozzleless electrospinning, or centrifugal spinning.

[0283] Form 50. 48. The composite filtration medium of embodiment 47, comprising 1 to 10 nanofiber layers and 2-11 support layers.

[0284] Form 51. 48. The composite filtration media of claim 47, comprising at least one outer support layer.

[0285] Form 52. 48. The composite filtration media of embodiment 47, comprising 2 to 10 nanofiber layers and 1 to 9 inner support layers.

[0286] Form 53. The nanofiber layer can be made of a polymer or an inorganic material; The polymers include, but are not limited to, PA (polyamide), PVDF (polyvinylidene fluoride), PI (polyimide), PAN (polyacrylonitrile), PES (polyethersulfone), TPU (thermoplastic polyurethane), PEI (polyetherimide), PS (polystyrene), PMIA (poly(m-phenylene isophthalamide)); The inorganic materials include, but are not limited to, Al2O3 (alumina), SiO2 (silica), and ZrO2 (zirconia). 48. The composite filtration medium of claim 47, wherein the nanofibers are continuous filaments or staple fibers.

[0287] Form 54. 48. The composite filtration media of claim 47, wherein the at least one support layer is made of a PET spunbond nonwoven, wetlaid nonwoven, or drylaid nonwoven.

[0288] Form 55. The composite filtration medium according to any one of the preceding claims, wherein the filtration efficiency of the composite filtration medium can reach 30-99.9999995%.

[0289] Form 56. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein the filtration efficiency is 60 to 85% and the flow resistance is 5 to 20 Pa when tested according to ISO 29463-3 or an equivalent standard.

[0290] Form 57. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 85 to 95% and the flow resistance is 15 to 50 Pa at a flow rate of 5.33 cm / s.

[0291] Form 58. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 85 to 95% and the flow resistance is 15 to 50 Pa at a flow rate of 5.33 cm / s.

[0292] Form 59. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 95 to 99.5% and the flow resistance is 30 to 150 Pa at a flow rate of 5.33 cm / s.

[0293] Form 60. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 99.5 to 99.95% and the flow resistance is 70 to 200 Pa at a flow rate of 5.33 cm / s.

[0294] Form 61. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 99.95 to 99.995% and the flow resistance is 120 to 230 Pa at a flow rate of 5.33 cm / s.

[0295] Form 62. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 99.995 to 99.9995% and the flow resistance is 150 to 280 Pa at a flow rate of 5.33 cm / s.

[0296] Form 63. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 99.9995 to 99.99995% and the flow resistance is 180 to 320 Pa at a flow rate of 5.33 cm / s.

[0297] Form 64. 48. The composite filtration medium of claim 47, characterized by high filtration efficiency and low flow resistance, wherein, when tested in accordance with ISO 29463-3 or an equivalent standard, the filtration efficiency is 99.99995 to 99.999995% and the flow resistance is 250 to 400 Pa at a flow rate of 5.33 cm / s.

[0298] Form 65. A method for preparing a multi-component nanofiber composite filtration media, comprising the steps of: 1) adding one or more first polymers to a solvent and stirring until completely dissolved to obtain a polymer solution A having a mass percent concentration of 10% to 50%; 2) adding one or more second polymers to a solvent and stirring until completely dissolved to obtain a polymer solution B having a mass percent concentration of 3% to 30%; 3) preparing two or more polymer solutions and injecting them into two or more electrospinning devices to produce nanofibers with two or more diameters; The nanofibers having two or more diameters are composited online to form a multi-component nanofiber structure, in which the weight ratio of the large diameter nanofibers to the fine nanofibers is 10:90 to 99:1; The multicomponent nanofibers are deposited on a support layer to form a composite filtration medium comprising the multicomponent nanofibers.

[0299] Form 66. where: The fine nanofibers have a minimum fiber diameter of 10 to 100 nm, a maximum fiber diameter of 200 to 300 nm, and an average fiber diameter of 30 to 150 nm; The large diameter nanofibers have a minimum diameter of 200 to 300 nm, a maximum fiber diameter of 1000 to 5000 nm, and an average fiber diameter of 300 to 3000 nm; and 66. The method of claim 65, wherein the multicomponent nanofiber composite filtration medium has a loftiness (void volume) of 70-90%.

[0300] Form 67. 66. The method of claim 65, wherein the pressure drop of the multicomponent nanofiber composite filtration medium is 5 to 500 Pa when the filtration efficiency is 60% to 99.9999999% under test conditions using a 0.3 μm NaCl polydisperse aerosol at a flow rate of 5.33 cm / s.

[0301] Form 68. 66. The method of claim 65, wherein the pressure drop of the multicomponent nanofibrous composite filtration medium does not exceed 500 Pa when the filtration efficiency is at least 60% under test conditions using a 0.3 μm NaCl polydisperse aerosol at a flow rate of 5.33 cm / s.

[0302] Form 69. 48. The composite filtration medium of claim 47, wherein the filtration efficiency is 60 to 85% and the flow resistance is 5 to 20 Pa when tested according to ISO 29463-3 or other equivalent standards, and the composite filtration medium has the characteristics of high efficiency and low flow resistance.

[0303] Form 70. 48. The composite filtration medium of claim 47, wherein the composite filtration medium has a filtration efficiency of 85 to 95% and a flow resistance of 15 to 50 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or other equivalent standards, and has the characteristics of high efficiency and low flow resistance.

[0304] Form 71. 48. The composite filtration medium of claim 47, wherein the composite filtration medium has a filtration efficiency of 85 to 95% and a flow resistance of 15 to 50 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or an equivalent standard, and thus has high efficiency and low flow resistance.

[0305] Form 72. 48. The composite filtration medium of claim 47, having high efficiency and low flow resistance, wherein the filtration efficiency is 95 to 99.5% and the flow resistance is 30 to 150 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or an equivalent standard.

[0306] Form 73. 48. The composite filtration medium of claim 47, having high efficiency and low flow resistance, wherein the filtration efficiency is 99.5 to 99.95% and the flow resistance is 70 to 200 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or an equivalent standard.

[0307] Form 74. 48. The composite filtration medium of claim 47, having high efficiency and low flow resistance, wherein the filtration efficiency is 99.95 to 99.995% and the flow resistance is 120 to 230 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or an equivalent standard.

[0308] Form 75. 48. The composite filtration medium of claim 47, having high efficiency and low flow resistance, wherein the filtration efficiency is 99.995 to 99.9995% and the flow resistance is 150 to 280 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or an equivalent standard.

[0309] Form 76. 48. The composite filtration medium of claim 47, having high efficiency and low flow resistance, wherein the filtration efficiency is 99.9995 to 99.99995% and the flow resistance is 180 to 320 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or an equivalent standard.

[0310] Form 77. 48. The composite filtration medium of aspect 47, having high efficiency and low flow resistance, wherein the filtration efficiency is 99.99995 to 99.999995% and the flow resistance is 250 to 400 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or an equivalent standard.

[0311] Form 78. 66. The method of claim 65, wherein the polymer is selected from the group consisting of polyurethane, polystyrene, polyimide, polyethylene glycol terephthalate, polybutylene terephthalate, nylon (nylon 6, nylon 66, nylon 56, nylon 1010), polyacrylonitrile, polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, chlorotrifluoroethylene, polyethylene oxide, polymethyl methacrylate, poly(m-phenylene isophthalamide), polysulfone, polyphenylene sulfone resin, polyethersulfone, polyphenylene sulfide, polyetherimide, polylactic acid, poly-L-lactic acid, poly-D-lactic acid, polycaprolactone, polyvinyl alcohol, polyvinylpyrrolidone, acrylic resin, cellulose acetate, chitosan, silk fibroin, and copolymers or homopolymers of these polymers, and any combination thereof.

[0312] Form 79. 66. The method of claim 65, wherein the solvent is selected from 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.

[0313] Form 80. 48. The high-efficiency, low-flow resistance composite filtration medium according to aspect 47, having a filtration efficiency of 60 to 99.9999995% and a filtration resistance of 5 to 500 Pa when tested according to ISO 29463-3 or an equivalent standard.

[0314] Form 81. 48. A high-efficiency, low-resistance composite filtration medium according to claim 47, having a filtration efficiency of at least 60% and a filtration resistance of less than 500 Pa when tested according to ISO 29463-3 or an equivalent standard.

[0315] Form 82. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 60 to 85% and a filtration resistance of 5 to 20 Pa when tested according to ISO 29463-3 or other equivalent standards.

[0316] Form 83. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 85 to 95% and a filtration resistance of 15 to 50 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or other equivalent standards.

[0317] Form 84. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 95 to 99.5% and a filtration resistance of 30 to 150 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or other equivalent standards.

[0318] Form 85. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 99.5 to 99.95% and a filtration resistance of 70 to 200 Pa at a flow rate of 5.33 cm / s when tested in accordance with ISO 29463-3 or other equivalent standards.

[0319] Form 86. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 99.95 to 99.995% and a filtration resistance of 120 to 230 Pa at a flow rate of 5.33 cm / s when tested according to ISO 29463-3 or other equivalent standards.

[0320] Form 87. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 99.995 to 99.9995% and a filtration resistance of 150 to 280 Pa at a flow rate of 5.33 cm / s when tested in accordance with ISO 29463-3 or other equivalent standards.

[0321] Form 88. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 99.9995 to 99.99995% and a filtration resistance of 180 to 320 Pa at a flow rate of 5.33 cm / s when tested in accordance with ISO 29463-3 or other equivalent standards.

[0322] Form 89. 48. A high-efficiency, low-flow resistance composite filtration medium according to claim 47, having a filtration efficiency of 99.99995 to 99.999995% and a filtration resistance of 250 to 400 Pa at a flow rate of 5.33 cm / s when tested in accordance with ISO 29463-3 or other equivalent standards.

[0323] Form 90. 10. The composite filtration media of any preceding claim, wherein the filtration media and activated carbon particles are combined to form an adsorptive composite filtration media.

[0324] Form 91. 1. A composite filtration medium comprising: support layer, Electrospun nanofiber layer, an adsorption layer comprising activated carbon; and A layer of large pore fibrous material.

[0325] Form 92. 92. The composite filtration media of claim 91, wherein a protective layer is disposed over the adsorbent layer, such that the adsorbent layer is an inner layer of the media.

[0326] Form 93. 92. The composite filtration media of claim 91, wherein the large pore fibrous material layer is selected from a meltblown nonwoven, an electrically charged media, a spunbond nonwoven, a wetlaid nonwoven, a drylaid nonwoven, a triboelectrically charged media, and any combination thereof.

[0327] Form 94. 92. The composite filtration medium of claim 91, wherein the nanofiber material is selected from thermoplastic polyurethane (TPU), polyvinylidene fluoride (PVDF), polyamide (PA), polyethersulfone (PES), polylactic acid (PLA), polyacrylonitrile (PAN), polyetherimide (PEI), polystyrene (PS), cellulose acetate (CA), or any combination thereof.

[0328] Form 95. 92. The composite filtration media of claim 91, wherein the activated carbon material comprises activated carbon and activated carbon containing adhesive powder or other adsorbent material.

[0329] Form 96. 92. The composite filtration media of claim 91, wherein the support layer has significant filtration efficiency.

[0330] Form 97. 92. The composite filtration media of claim 91, wherein the support layer has significant dust retention capacity.

[0331] Form 98. 92. The composite filtration media of claim 91, wherein adjacent layers are adhered by any one or any combination of ultrasonic adhesion, hot melt spray adhesion, powder adhesive thermocompression adhesion, or adhesive transfer adhesion.

[0332] Form 99. 92. The composite filtration media of claim 91, wherein the support layer comprises a thermoplastic polymer resin.

[0333] Form 100. 92. The composite filtration media of embodiment 91, wherein each layer of the at least two layers comprises an antimicrobial agent.

[0334] Form 101. 92. The composite filtration medium of claim 91, wherein the nanofiber layer comprises nozzle-type electrospun nanofibers, nozzleless electrospun nanofibers, centrifugal spun nanofibers, or any combination thereof.

[0335] Form 102. 92. The composite filtration medium of claim 91, wherein vitamin C (VC) is added at a concentration of 1% to 10% by electrospinning.

[0336] Form 103. 92. The composite filtration medium of claim 91, comprising 10% to 50 wt% vitamin C within the fibers of the electrospun nanofiber layer.

[0337] Form 104. 92. The composite filtration medium of claim 91, wherein the nanofibers in the nanofiber layer have an average fiber diameter of <5 μm.

[0338] Form 105. 92. The composite filtration medium of claim 91, wherein the nanofibers in the nanofiber layer have an average fiber diameter of <1 μm.

[0339] Form 106. 92. The composite filtration medium of claim 91, wherein the nanofibers have an average diameter of <0.5 μm.

[0340] Form 107. 92. The composite filtration medium of claim 91, wherein the flow resistance is 3 to 100 Pa and the filtration efficiency is 25% to 99.999% under conditions of a flow rate of 5.33 cm / s and using 0.3 μm NaCl.

[0341] Form 108. 92. The composite filtration medium according to claim 91, wherein the composite filtration medium has a flow resistance of 2 to 10 Pa and a filtration efficiency of 20 to 85% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0342] Form 109. 92. The composite filtration medium according to claim 91, wherein the composite filtration medium has a filtration efficiency of 75 to 95% for 0.3 μm NaCl at a flow rate of 5.33 cm / s, and an air resistance of 10 to 30 Pa.

[0343] Form 110. 92. The medium of claim 91, wherein the composite filtration medium has an air flow resistance of 30-50 Pa and a filtration efficiency of 90-99.9% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0344] Form 111. 92. The medium of claim 91, wherein the composite filtration medium has an air flow resistance of 50-70 Pa and a filtration efficiency of 99-99.95% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0345] Form 112. 92. The medium of claim 91, wherein the composite filtration medium has an air flow resistance of 70-100 Pa and a filtration efficiency of 99.5-99.999% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0346] Form 113. the support layer is made of polyethylene terephthalate (PET), The nanofiber layer is made of fibers containing any one of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyetherimide (PEI), polystyrene (PS), polyamide (PA), polylactic acid (PLA), polyethersulfone (PES), thermoplastic polyurethane (TPU), and cellulose acetate (CA), or any combination thereof; the adsorbent bed comprises activated carbon or other adsorbent material; 92. The composite filtration media of claim 91, wherein the top layer comprises a needle-punched tribo-electrically charged media.

[0347] Form 114. The weight per unit area of ​​the needle-punched friction charging medium is 30 to 100 g / m 2 114. The composite filtration medium according to claim 113, wherein the thickness is 0.3 to 1.2 mm, the flow resistance is 3 to 30 Pa at a flow velocity of 16.7 cm / s, and the filtration efficiency is 25 to 95% at a flow velocity of 26.25 cm / s.

[0348] Form 115. The support layer is a dry-laid nonwoven fabric made of polyethylene terephthalate (PET), and its weight per unit area is 40 to 100 g / m 2 92. The composite filtration medium according to claim 91, wherein the thickness is 0.25 to 0.5 mm, and the tensile strength is 100 to 250 N / 5 cm (vertical direction) and 30 to 90 N / 5 cm (horizontal direction).

[0349] Form 116. 92. The composite filtration medium of claim 91, comprising electrospun fibers having a diameter of about 0.03-5 μm, a flow resistance of 3-100 Pa, and a filtration efficiency of 25-99.9999% under test conditions of a flow rate of 5.33 cm / s and 0.3 μm NaCl, the fibers being electrospun onto a PET nonwoven substrate.

[0350] Form 117. 92. The medium of claim 91, wherein the composite filtration medium has an airflow resistance of 2-10 Pa and an efficiency of 20-85% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0351] Form 118. 92. The medium of claim 91, wherein the composite filtration medium has an airflow resistance of 10-30 Pa and an efficiency of 75-95% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0352] Form 119. 92. The medium of claim 91, wherein the composite filtration medium has an airflow resistance of 30-50 Pa and an efficiency of 90-99.9% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0353] Form 120. 92. The medium of claim 91, wherein the composite filtration medium has an airflow resistance of 50-70 Pa and an efficiency of 99-99.95% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0354] Form 121. 92. The medium of claim 91, wherein the composite filtration medium has an airflow resistance of 70-100 Pa and an efficiency of 99.5-99.999% for 0.3 μm NaCl at a flow rate of 5.33 cm / s.

[0355] Form 122. The weight per unit area of ​​the needle-punched friction charging medium is 10 to 200 g / m 2 The composite filtration medium according to any one of the preceding claims, having a thickness of 0.3 to 1.2 mm, a flow resistance of 2.5 to 10 Pa at a flow rate of 5.33 cm / s, and a filtration efficiency of 25 to 95% for 0.3 μm NaCl at a flow rate of 5 to 50 cm / s.

[0356] Form 123. the support layer comprises polyethylene terephthalate (PET) or polypropylene (PP); The nanofiber layer comprises any one or a combination of polyvinylidene fluoride (PVDF), polyamide (PA), thermoplastic polyurethane (TPU), polyethersulfone (PES), polyacrylonitrile (PAN), polyetherimide (PEI), polystyrene (PS), polylactic acid (PLA), and cellulose acetate (CA); the adsorption layer comprises activated carbon; 92. The composite filtration media of claim 91, wherein the top layer comprises a meltblown nonwoven.

[0357] Form 124. the support layer is a polyethylene terephthalate (PET) or polypropylene (PP) nonwoven fabric substrate; the nanofiber layer comprises electrospun nanofibers; the adsorption layer comprises activated carbon; 92. The composite filtration media of claim 91, wherein the top layer comprises a meltblown nonwoven, a triboelectrically charged media, or other electrostatically charged media.

[0358] Form 125. 1. A method for preparing a composite material comprising nanofibers, comprising the steps of: a) A spinning solution is prepared by mixing a nanofiber polymer material with a solvent and optional additives. b) The nanofiber solution is spun onto a support layer by electrospinning to form a nanofiber layer. The electrospinning procedure is as follows: flow rate 0.001-1.0 ml / min / nozzle (ml / min / needle), voltage 15-70 kV, DCD 10-30 cm, and temperature and humidity are controlled. c) dispersing an adsorbent material onto the nanofiber layer or other adjacent layer; d) A top layer is disposed on the adsorption layer, and the material of the top layer is selected from any one of meltblown nonwoven fabric, triboelectric charging medium, dry-laid nonwoven fabric, wet-laid nonwoven fabric, spunbond nonwoven fabric, or any combination thereof.

[0359] Form 126. the nanofiber layer comprises a multi-layer nanofiber structure; 126. The method of claim 125, wherein the nanofiber layers and the inner support layer are alternated to increase filtration efficiency, reduce pressure drop, and increase the dust holding capacity of the media.

[0360] Form 127. the nanofiber layer comprises a multicomponent nanofiber layer; The preparation method according to form 125, wherein a large-diameter nanofiber layer having a lofty structure and fine nanofibers are composite-treated to further increase filtration efficiency, reduce pressure drop, and increase the dust holding capacity of the medium.

[0361] Form 128. 126. The method of claim 125, wherein the nanofiber layer further comprises submicron and micron fibers having a fiber diameter of ≦60 μm.

[0362] Form 129. the submicron and micron fibers are short fibers and / or continuous filaments; and 126. The method of claim 125, wherein the polymer or inorganic material is used.

[0363] Form 130. 126. The method of preparing a fiber according to claim 125, wherein the submicron and micron fibers comprise any one of PA6 (polyamide 6), PA56 (polyamide 56), PA1010 (polyamide 1010), PAN (polyacrylonitrile), PLA (polylactic acid), PU (polyurethane), PVDF (polyvinylidene fluoride), CA (cellulose acetate), PEI (polyetherimide), PS (polystyrene), PES (polyethersulfone), PMIA (poly(m-phenylene isophthalamide)), PTFE (polytetrafluoroethylene), Al2O3 (alumina), SiO2 (silica), ZrO2 (zirconia), PP (polypropylene), PE (polyethylene), PET (polyethylene terephthalate), PET / PE, PET / low melting point PET (PET / LMPET), and glass fibers, or any combination thereof.

[0364] Form 131. 126. The method of claim 125, wherein the nanofibers to micron and / or submicron fibers are present in a quantity ratio of 1:6 to 600:1 and in a weight ratio of 1:99 to 10:1.

[0365] Form 132. the nanofiber layer (1) is formed by depositing nanofibers, micron fibers, and / or submicron fibers simultaneously onto an inner support layer (2) and a first outer support layer (31) by electrospinning; where: Nanofiber diameter ≤ 5 μm, Submicron and micron fibers with a diameter of ≦100 μm; The fiber diameter of the inner support layer (2) is 0.5 μm to 100 μm. 126. The method of claim 125, wherein the ratio of nanofibers to micron and / or submicron fibers is 1:2 to 600:1 in terms of quantity and 1:99 to 10:1 in terms of weight.

[0366] Form 133. 92. The composite filtration medium of claim 91, wherein the nanofiber layer deposited on the nonwoven substrate layer comprises electrospun nanofibers having a diameter of 0.01-3 μm, and at a flow rate of 1.8-26.7 cm / s, the nanofiber layer has a flow resistance of 1-15 Pa, a filtration efficiency of 20-99.95%, an activated carbon particle size of 10-150 mesh, an iodine value of 100-4000, a hardness of about 98, and an ash content of 1-20%.

[0367] Form 134. 92. The composite filtration medium of claim 91, wherein the support layer comprises PET, the nanofiber layer comprises any one or combination of PVDF (polyvinylidene fluoride), PA (polyamide), PES (polyethersulfone), PAN (polyacrylonitrile), TPU (thermoplastic polyurethane), PS (polystyrene), PEI (polyetherimide), PLA (polylactic acid), CA (cellulose acetate), and the large diameter fibrous material layer comprises any one or combination of meltblown, triboelectrically charged, spunbonded, or drylaid nonwovens.

[0368] Form 135. 1. A composite filtration medium comprising: A first distribution of nanofibers, a second distribution of fibers in contact with the first distribution of nanofibers; the first distribution of nanofibers has a peak diameter distribution of less than 150 nm; the peak diameter distribution of the second distribution of fibers is greater than the first peak diameter distribution; and The composite filtration media has a void volume greater than 70%.

[0369] Form 136. 136. The composite filtration medium of claim 135, wherein the second peak diameter distribution is from 0.3 μm to 25 μm.

[0370] Form 137. 136. The composite filtration medium of claim 135, wherein the second fiber distribution comprises a second peak diameter distribution of 300 to 1000 nm, and the weight ratio of the first nanofiber distribution to the second fiber distribution is 10:90 to 70:30.

[0371] Form 138. 136. The composite filtration medium of claim 135, wherein the second fiber distribution comprises a second peak diameter distribution of 1.0 to 2.0 μm, and the weight ratio of the first nanofiber distribution to the second fiber distribution is 10:90 to 60:40.

[0372] Form 139. 136. The composite filtration medium of claim 135, wherein the second fiber distribution comprises a second peak diameter distribution of 1.5 to 3.0 μm, and the weight ratio of the first nanofiber distribution to the second fiber distribution is 10:90 to 60:40.

[0373] Form 140. 139. The composite filtration medium of any one of claims 135 to 139, wherein the composite filtration medium has a filtration efficiency of 90% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s and an airflow resistance of 40 Pa or less.

[0374] Form 141. 139. The composite filtration medium of any one of claims 135 to 139, wherein the composite filtration medium has a filtration efficiency of 99.5% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and an airflow resistance of 150 Pa or less.

[0375] Form 142. 139. The composite filtration medium of any one of claims 135 to 139, wherein the composite filtration medium has a filtration efficiency of 99.95% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and an airflow resistance of 180 Pa or less.

[0376] Form 143. 139. The composite filtration medium of any one of claims 135 to 139, wherein the composite filtration medium has a filtration efficiency of 99.995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and an airflow resistance of 230 Pa or less.

[0377] Form 144. 139. The composite filtration medium of any one of claims 135 to 139, wherein the composite filtration medium has a filtration efficiency of 99.9995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and an airflow resistance of 270 Pa or less.

[0378] Form 145. 139. The composite filtration medium of any one of claims 135 to 139, wherein the composite filtration medium has a filtration efficiency of 99.99995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and an airflow resistance of 320 Pa or less.

[0379] Form 146. 139. The composite filtration medium of any one of claims 135 to 139, wherein the composite filtration medium has a filtration efficiency of 99.999995% or greater for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and an airflow resistance of 370 Pa or less.

[0380] Form 147. 140. The composite filtration medium of any one of embodiments 135 to 139, wherein the nanofiber-containing layer has a void volume of 85 to 95%.

[0381] Form 148. 140. The composite filtration medium of any one of embodiments 135 to 139, wherein the first distribution of nanofibers and the second distribution of fibers are laminated to a support layer.

[0382] Form 149. 136. The composite filtration medium of claim 135, wherein the support layer is a bicomponent spunbond fiber comprising a PE skin layer / PET core layer.

[0383] Form 150. 1. A composite filtration medium comprising: A multi-layer structure, including: a nanofiber layer, the nanofiber layer including a first fiber distribution having an average fiber diameter of 10 nm to 200 nm; a support layer, the support layer including a second fiber distribution having an average fiber diameter of 0.3 to 25 μm; and The multi-layer structure includes a support layer between at least two nanofiber layers.

[0384] Form 151. 10. The composite filtration media of any preceding claim, wherein the support layer comprises a spunbond, meltblown, or needlepunched fiber construction.

[0385] Form 152. The sum of the weight per unit area of ​​the nanofiber layer and the adjacent support layer is 8 to 35 g / m 2 2. The composite filtration medium of claim 1, wherein

[0386] Form 153. 136. The composite filtration medium of claim 135, wherein the nanofiber layer comprises any one of PVDF (polyvinylidene fluoride), PAN (polyacrylonitrile), PES (polyethersulfone), PA (polyamide), TPU (thermoplastic polyurethane), PS (polystyrene), CA (cellulose acetate), or PEI (polyetherimide) fibers, or any combination thereof.

[0387] Form 154. 10. The composite filtration medium of any preceding claim, wherein the nanofiber layer further comprises a third fiber distribution (average diameter 300-3000 nm) mixed with the first fiber distribution.

[0388] Form 155. 10. The composite filtration media of any preceding claim, further comprising an outer protective layer (comprising charged fibers).

[0389] Form 156. 10. The composite filtration media of any preceding claim, further comprising a layer comprising activated carbon.

[0390] Form 157. 10. The composite filtration media of any preceding claim, wherein the filtration efficiency for 0.3 μm NaCl particles is 90% or more and the flow resistance is not more than 40 Pa at a flow rate of 5.33 cm / s.

[0391] Form 158. 10. The composite filtration media of any preceding claim, wherein the filtration efficiency for 0.3 μm NaCl particles is 99.5% or more at a flow rate of 5.33 cm / s, and the flow resistance does not exceed 150 Pa.

[0392] Form 159. 10. The composite filtration media of any preceding claim, wherein the filtration efficiency for 0.3 μm NaCl particles is 99.95% or more and the flow resistance does not exceed 180 Pa when the flow velocity is 5.33 cm / s.

[0393] Form 160. 10. The composite filtration media of any preceding claim, wherein the filtration efficiency for 0.3 μm NaCl particles is 99.995% or more at a flow rate of 5.33 cm / s, and the flow resistance does not exceed 230 Pa.

[0394] Form 161. 10. The composite filtration media of any preceding claim, wherein the filtration efficiency for 0.3 μm NaCl particles is 99.9995% or more at a flow rate of 5.33 cm / s, and the flow resistance does not exceed 270 Pa.

[0395] Form 162. 10. The composite filtration media of any preceding claim, wherein the filtration efficiency for 0.3 μm NaCl particles is 99.99995% or more at a flow rate of 5.33 cm / s, and the flow resistance does not exceed 320 Pa.

[0396] Form 163. 10. The composite filtration media of any preceding claim, wherein the filtration efficiency for 0.3 μm NaCl particles is 99.999995% or more at a flow rate of 5.33 cm / s, and the flow resistance does not exceed 370 Pa.

[0397] Form 164. The multicomponent nanofiber layer comprises large and small electrospun nanofibers, wherein: The ratio of the number of small-sized nanofibers to the number of large-sized nanofibers produced by the electrospinning method is 10:1 to 1000:1, preferably 30:1 to 300:1, more preferably 80:1 to 200:1; The weight ratio is 10:90 to 90:10, preferably 30:70 to 70:30, The composite filtration medium according to any one of the preceding claims, wherein the average fiber diameter ratio is from 1:3 to 1:100, more preferably from 1:5 to 1:30.

[0398] Form 165. The multicomponent nanofiber layer comprises electrospun nanofibers and staple fibers, wherein: The ratio of the quantity of electrospun nanofibers to the quantity of large staple fibers is 10:1 to 1000:1, preferably 50:1 to 300:1, and more preferably 80:1 to 200:1; The weight ratio is 1:300 to 10:1, more preferably 1:100 to 60:40, 10. The composite filtration medium according to any one of the preceding claims, wherein the average fiber diameter ratio is from 1:10 to 1:1000, preferably from 1:10 to 1:200.

[0399] Form 166. The inner support layer comprises a meltblown nonwoven fabric, and the meltblown nonwoven fabric has an average fiber diameter of 0.5 to 7 μm, preferably 1 to 5 μm, and a weight per unit area of ​​5 to 50 g / m 2 , preferably 8-20 g / m 2 2. The composite filtration medium of claim 1, wherein

[0400] Form 167. The inner support layer comprises a spunbond nonwoven fabric, and the spunbond nonwoven fabric has an average fiber diameter of 6 to 30 μm, preferably 10 to 20 μm, more preferably 12 to 16 μm, and a weight per unit area of ​​5 to 50 g / m 2 , preferably 8 to 20 g / m 22. The composite filtration medium of claim 1, wherein

[0401] Form 168. The first outer support layer is used to provide strength and rigidity to the composite filtration media and has a weight per unit area of ​​20 to 150 g / m. 2 , preferably 40 to 130 g / m 2 and The second outer support layer is used for protection and / or dust retention, and its weight per unit area is 10 to 150 g / m 2 , preferably 15 to 100 g / m 2 2. The composite filtration medium of claim 1, wherein

[0402] Form 169. 1. A composite filtration medium comprising: First, nanofiber distribution, a second fiber distribution contacting the first nanofiber distribution; the first nanofiber distribution has a fiber diameter distribution peak value of less than 150 nm; and The fiber diameter distribution peak value of the second fiber distribution is greater than the first peak value; The composite filtration media has a porosity greater than 70%.

[0403] Form 170. 169. The composite filtration medium of claim 169, wherein the second peak value is 0.3 μm to 25 μm.

[0404] Form 171. 169. The composite filtration medium of claim 169, wherein the second fiber distribution comprises a second peak value of 300 to 1000 nm, and the weight ratio of the first nanofiber distribution to the second fiber distribution is 10:90 to 70:30.

[0405] Form 172. the second fiber distribution includes a diameter distribution with a peak value of 1.0 to 3.0 μm; 169. The composite filtration medium of embodiment 169, wherein the weight ratio of the first nanofiber distribution to the second fiber distribution is 10:90 to 60:40.

[0406] Form 173. The composite filtration medium according to any one of the preceding claims, wherein the layer containing nanofibers has a porosity of 85 to 95%.

[0407] Form 174. 10. The composite filtration media of any preceding claim, wherein the first nanofiber distribution layer and the second fiber distribution layer are laminated onto a support layer.

[0408] Form 175. 175. The composite filtration medium of claim 174, wherein the support layer comprises bicomponent spunbond fibers, the fibers having a polyethylene (PE) surface layer and a polyethylene terephthalate (PET) core layer structure.

[0409] Form 176. A composite filtration medium, comprising a multi-layer structure; where: a nanofiber layer, the nanofiber layer comprising a first fiber diameter distribution having a peak value of 10 to 200 nm; a support layer, the support layer including a second fiber diameter distribution having a peak value of 0.3 to 25 μm; and The multi-layer structure includes a support layer between at least two nanofiber layers.

[0410] Form 177. 177. The composite filtration medium of claim 176, wherein the support layer comprises a spunbond, meltblown, or needlepunched fiber structure.

[0411] Form 178. The sum of the weight per unit area of ​​the nanofiber layer and the adjacent support layer is 8 to 35 g / m 2 177. The composite filtration medium of claim 176, wherein

[0412] Form 179. 177. The composite filtration medium of claim 176, wherein the nanofiber layer comprises polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyethersulfone (PES), polyamide (PA), thermoplastic polyurethane (TPU), or polyetherimide (PEI) fibers.

[0413] Form 180. 177. The composite filtration medium of claim 176, wherein the nanofiber layer further comprises a third fiber diameter distribution intermixed with the first fiber distribution, the third fiber diameter distribution having a peak value between 300 and 1000 nm.

[0414] Form 181. 177. The composite filtration media of claim 176, further comprising an outer protective layer, the outer protective layer comprising electrically charged fibers.

[0415] Form 182. 177. The composite filtration media of claim 176, further comprising an activated carbon-containing layer.

[0416] Form 183. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 70% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 20 Pa.

[0417] Form 184. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 90% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 40 Pa.

[0418] Form 185. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 99% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 120 Pa.

[0419] Form 186. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 99.5% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 150 Pa.

[0420] Form 187. 183. The composite filtration medium of any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 99.95% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 180 Pa.

[0421] Form 188. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 99.995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 230 Pa.

[0422] Form 189. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 99.9995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 270 Pa.

[0423] Form 190. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 99.99995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 320 Pa.

[0424] Form 191. 183. The composite filtration medium according to any one of embodiments 169 to 182, wherein the composite filtration medium has a filtration efficiency of 99.999995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and an air resistance of not more than 370 Pa.

[0425] The above description is illustrative and not restrictive. For example, the above embodiments (or one or more aspects thereof) can be used in combination with each other. Those skilled in the art can adopt other embodiments based on the above description. In accordance with the provisions of Title 37, Code of Federal Regulations, Section 1.72(b), the Abstract is provided to enable readers to quickly understand the substance of the technical solution, and it is expressly stated that it should not be used to interpret or limit the scope or meaning of the claims when submitted. Furthermore, the above detailed description may describe various combinations of features to simplify the disclosure. These combinations should not be construed as essential technical features of any claim, even if they are not claimed for protection. The substance of the invention may be embodied in some technical features of a particular embodiment. Therefore, the following claims are incorporated into the detailed description, with each claim existing as an independent embodiment, and these embodiments can be combined with each other in various combinations or arrangements. The scope of the present invention is defined by the appended claims and their legal equivalents.

[0426] Although the inventive concept has been described with reference to specific embodiments, various modifications and changes can be made to these embodiments without departing from the broader scope of each embodiment of the invention. Embodiments based on the inventive concept may be referred to herein, singly or collectively, as the "invention," but this is for convenience only and is not intended to limit the scope of the present application to any single technical implementation (if multiple embodiments are actually disclosed).

[0427] All embodiments have been described in detail in this specification to enable those skilled in the art to implement the disclosed technical means. Other embodiments may be applied based on this description. Accordingly, the structure and logical relationships may be interchanged and modified without departing from the scope of the present disclosure. The above detailed description does not limit the present invention, and the scope of each embodiment is defined by the appended claims and all claims with legal equivalents.

[0428] In this specification, the term "or" may be interpreted as either inclusive or exclusive. Furthermore, multiple instances of a resource, operation, or structure described herein may be provided for a single instance. Furthermore, the boundaries between each resource, operation, module, engine, and data store may be freely defined within certain boundaries, and specific operations are described in specific descriptive paragraphs. Other distributions of functionality are contemplated and may fall within the scope of each embodiment of the present disclosure. In general, structures and functions described as a single resource in the examples may be implemented as a combined structure or resource. Similarly, structures and functions described as a single resource may also be implemented as a single resource. This means that all other variations, modifications, additions, and improvements are intended to be within the scope of the embodiments of the present disclosure, as defined in the appended claims. Accordingly, the specification and drawings are illustrative, not limiting.

[0429] For purposes of explaining the present invention, the foregoing description has been given with reference to specific exemplary embodiments. However, the foregoing illustrative discussion is intended to be exhaustive of possible exemplary embodiments and is not intended to limit the present invention to the precise form disclosed. As noted above, various modifications and variations can be made to the present invention. The exemplary embodiments have been selected or described to better explain the principles involved and their practical application, and to enable those skilled in the art to better utilize various modified embodiments suited to the particular uses envisioned.

[0430] In this specification, the terms "first" and "second" may be used to describe various elements, but these elements should not be understood to be limited by these terms. These terms are used to distinguish one element from another. For example, a first contact member may be referred to as a second contact member, and similarly, a second contact member may be referred to as a first contact member, without departing from the scope of the illustrative embodiments. The first contact member and the second contact member are both contact members, but are not the same contact member.

[0431] The terms used herein when describing exemplary embodiments are used only to describe the particular exemplary embodiment and are not limiting. As used in the description of the exemplary embodiments and the accompanying examples, the singular forms "a," "an," and "the" include the plural, unless otherwise stated. Also, the term "and / or" means to include any and all possible combinations of one or more of the associated items. Furthermore, as used herein, the terms "comprise" and / or "comprises" indicate the presence of features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0432] The term "if" as used herein may be understood, based on context, as "upon" or "when" or "responsive to determining" or "responsive to detecting." Similarly, based on context, the phrase "if determined" or "if [said condition or event] is detected" may be understood as "when determining" or "responsive to determining" or "when [said condition or event] is detected" or "responsive to detected [said condition or event]." [Explanation of symbols]

[0433] Regarding Figures 1 to 9 1, nanofiber layer, 11, first nanofiber layer, 12, second nanofiber layer, 13, third nanofiber layer, 14, fourth nanofiber layer, 15, fifth nanofiber layer, 16, sixth nanofiber layer. 2, inner support layer, 21, first inner support layer, 22, second inner support layer, 23, third inner support layer, 24, fourth inner support layer, 25, fifth inner support layer, 26, sixth inner support layer. 3, outer support layer; 31, first outer support layer; 32, second outer support layer; Regarding Figures 11 and 17 11A - first multicomponent nanofiber layer 80%, 12A - second multicomponent nanofiber layer 95%, 13A - third multicomponent nanofiber layer 99%. 21A-First inner support layer 20g / m2 22A - Second inner support layer 20g / m 2 . 31A - First outer support layer 35g / m 2 32A - Second outer support layer 35g / m 2 .

Claims

1. 1. A composite filtration medium comprising: a first nanofiber distribution; a second fiber distribution contacting the first nanofiber distribution; the first nanofiber distribution has a first diameter distribution having a peak value less than 150 nm; the second fiber distribution comprises a second diameter distribution, the peak value of which is greater than the first peak value; A composite filtration medium having a void volume greater than 70%.

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

3. the second fiber distribution includes a second peak value between 300 and 1000 nm; 2. The composite filtration media of claim 1, wherein a weight ratio of the first nanofiber distribution to the second fiber distribution is from 10:99 to 70:

30.

4. the second fiber distribution comprises a second diameter distribution having a peak value of 1.0 to 3.0 μm; 2. The composite filtration media of claim 1, wherein the weight ratio of the first nanofiber distribution to the second fiber distribution is from 10:99 to 60:

40.

5. 5. The composite filtration medium of claim 1, wherein the nanofiber-containing layer has a void volume of 85-95%.

6. 6. The composite filtration medium of claim 1, wherein the first nanofiber distribution and the second fiber distribution are layered on a support layer.

7. 7. The composite filtration media of claim 6, wherein the support layer comprises bicomponent spunbond fibers having a polyethylene (PE) face layer and a polyethylene terephthalate (PET) core layer.

8. 1. A composite filtration medium comprising: A plurality of layers, including: a nanofiber layer, the nanofiber layer comprising a first fiber diameter distribution having a peak value between 10 nm and 200 nm; a support layer, the support layer comprising a second fiber diameter distribution having a peak value of 0.3 to 25 μm; A composite filtration medium, wherein the support layer is disposed between at least two nanofiber layers among the plurality of layers.

9. 9. The composite filtration media of claim 8, wherein the support layer comprises a spunbond, meltblown, or needlepunched fiber structure.

10. The weight per unit area of ​​the nanofiber layer and the adjacent support layer is 8 to 35 g / m ２ 9. The composite filtration media of claim 8, wherein:

11. 9. The composite filtration media of claim 8, wherein the nanofiber layer comprises polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyethersulfone (PES), polyamide (PA), and thermoplastic polyurethane (TPU) or polyetherimide (PEI) fibers.

12. the nanofiber layer further comprises a third fiber diameter distribution intermixed with the first fiber distribution; 9. The composite filtration media of claim 8, wherein the third fiber diameter distribution has a peak value between 300 and 1000 nm.

13. further comprising an outer protective layer; 10. The composite filtration media of claim 8, wherein the outer protective layer comprises electrically charged fibers.

14. 12. The composite filtration media of claim 11, further comprising an activated carbon-containing layer.

15. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 70% or more, and the flow resistance is not more than 20 Pa.

16. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 90% or more, and the flow resistance is not more than 40 Pa.

17. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 99% or more, and the flow resistance is not more than 120 Pa.

18. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 99.5% or more, and the flow resistance is not more than 150 Pa.

19. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 99.95% or more, and the flow resistance is not more than 180 Pa.

20. The composite filtration medium according to any one of claims 1 to 14, wherein the composite filtration medium has a filtration efficiency of 99.995% or more for 0.3 μm NaCl particles at a flow rate of 5.33 cm / s, and a flow resistance of not more than 230 Pa.

21. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 99.9995% or more, and the flow resistance is not more than 270 Pa.

22. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 99.99995% or more, and the flow resistance is not more than 320 Pa.

23. The composite filtration medium according to any one of claims 1 to 14, characterized in that, when the flow velocity is 5.33 cm / s, the filtration efficiency for 0.3 μm NaCl particles is 99.999995% or more, and the flow resistance is not more than 370 Pa.

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