WO2024173374A1 - A fully synthetic polymeric filter media - Google Patents

Abstract

A composite filter media for filtering liquids is shown comprising a top layer comprising a polymeric material of polymer fibers. A middle layer is arranged below the top layer and comprises a polymeric material of polymer fibers wherein the middle layer has a basis weight. A bottom layer is arranged below the middle layer and comprises a polymeric material of polymer fibers wherein the bottom layer has a basis weight. A polymeric support layer having a basis weight is arranged below the bottom layer.

Description

A FULLY SYNTHETIC POLYMERIC FILTER MEDIA

Cross Reference to Related Applications

[0001] This application is a nonprovisional application that claims benefit of and priority to US provisional application 63/445,176 filed February 13, 2023, the contents of which are herein incorporated by reference in their entirety.

Technical Field

[0002] The present disclosure relates generally to a composite filter media and its preparation method.

Background

[0003] Engine exhaust emission standards have become increasingly more strict over time, which requires better engine design to be more efficient and produce less emissions. With the development of engine technology, the requirements for fuel, oil, and other liquid cleanliness have been raised. With the higher operating pressures in today’s engines, even very small particles can wear down and otherwise damage the precision components in the engine system such as the injection nozzle. In the meantime, the fuel changes have also affected filtration requirements. Some significant changes include the switch to ultra low sulfur diesel fuel and the use of environmentally friendly biodiesel. Sulfur and sulfur compounds in past fuel blends aided with lubrication and wear of engine components. Biodiesel and other alternative fuels often have a higher water content than traditional diesel. Due to these differences as well as normal transportation of fuels, some debris and water will enter into fuel causing contamination. During the use of the vehicle, the solid debris in the fuel will cause the wear of the engine system and the blockage of the fuel injection nozzle. Water in the fuel will cause combustion instability and corrosion of components. Therefore, the requirements for the fuel filtration becomes more stringent, and the standards for the filter material are also raised. [0004] To achieve the goal of efficient filtration, glass fiber is commonly used as the filter material for fuel oil filtration in the market at present. However, the brittleness of glass fiber makes the filter material easy to break during processing and use. It is easy to generate secondary contamination and cause damage to the engine, so it is of great significance to develop a durable high-efficiency and long-life full synthetic liquid filter material. All synthetic materials have good toughness, are not prone to fracture, and can extend the service life of filter and engine. Secondly, by proper selection of polymeric materials which have efficient filtration and separation properties, high efficiency filtration of liquids can be achieved.

[0005] An improved filter media made of low-shedding fully synthetic polymer materials that provides high-performance filter materials with improved efficiency and higher dust loading capacity while maintaining the low resistance and small thickness is needed. The disclosed inventive media and technology provides a device and method that fulfills this desired need.

[0006] The art referred to and/or described within this application is not intended to constitute an admission that any patent, publication or other information referred to herein is "prior art" with respect to this invention. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists.

[0007] All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.

[0008] Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.

[0009] A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.

Brief Description of the Drawings

Atty. Dkt. No. 6240.001W01 2 [0010] FIG 1 is a cross-sectional view of an embodiment of the composite filter media.

[0011] FIG 2 is a cross-sectional view of an embodiment of the composite filter media that uses two filter media layers in both the top layer and the middle layer.

[0012] FIG 3 is a cross-sectional view of an embodiment of the composite filter media that uses two filter media layers in the bottom layer. [0013] FIG 4 is a cross-sectional view of an embodiment of the composite filter media that uses an optional protective layer.

[0014] FIG 5 is a cross-sectional view of an embodiment of the composite filter media that uses a protective layer and a two-component fiber mixture in the top layer.

[0015] FIG 6 is a cross-sectional view of an embodiment of the composite filter media that uses a protective layer and three filter media layers in the middle layer.

[0016] FIG 7 is a view of a cartridge filter element that uses the composite filter media.

Description of Embodiments

[0017] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

[0018] A fully synthetic composite filter media for liquid filtration applications has high filtration and separation efficiency filtration, high dust loading capacity, long service life, and low resistance to liquid flow. All filter media material use fully synthetic polymer fiber materials. The filter media is substantially free of cellulose fiber or glass fiber. The composite filter media has an overall thickness of less than 2 mm and a basis weight of 180g/m² to 400g/m². The particle filtration efficiency of the full synthetic composite filter media can range from 70% to 99.95% @4pm while the dust holding capacity can be greater than 150 g/m².

Atty. Dkt. No. 6240.001W01 3 [0019] The composite liquid filtration materials can comprise multiple microfiber layers, with fiber diameter in the range of 0.5 micron -10 micron. The microfiber layers can form a gradient structure from top layer to the bottom layer, with decreasing fiber diameter, pore size, and air permeability. The composite liquid filtration material includes a support layer, with basis weight of 70-250 g/m², providing overall strength and stiffness of the media. The media may contain a protection layer, with basis weight of 10-30 g/m^2, the support layer and optional protection layer can be PET, PA, or other polymer material. [0020] FIG 1 shows a cross-section view of an embodiment of the composite filter media. The composite filter media 1 comprises at least four layers of structure from an upstream to downstream direction, namely the top layer 2, the middle layer 3, the bottom layer 4 as functional filtration layers and the support layer 5. An optional protection layer can be used above the top layer. The average fiber diameter of the top, middle and bottom functional layers can decrease from top to bottom.

[0021] The top layer can be made of polymeric material, comprising meltblown materials, bicomponent materials, dry laid nonwoven fabrics, spunlaced nonwoven fabrics, commingled materials, etc. The commingled material can comprise a nonwoven fabric comprising a mixture of coarse staple fiber and fine meltblown fibers. The coarse staple fiber can include PET, PA, and the meltblown can be PBT, PET, PA etc. The top layer can be a single filter media layer, or multiple filter media layers combined. The multiple filter media layers can have different properties and use different polymer fibers. The average fiber diameter of the top layer can be between 4pm and 25 pm, the deviation of the average fiber diameter between the two adjacent layers shall not exceed 10pm when multiple media layers are combined. The basis weight of the top layer can be 20g/m² - 100g/m².

[0022] The middle layer can be a polymeric material, usually including meltblown nonwoven fabrics and/or two-component materials. The melt-blown non-woven materials can be PBT, PET, PA, PLA. The average fiber diameter of the middle layer can be between 1 p m and 5 p m. The middle layer can comprise a single filter media layer or multiple filter media layers combined. The multiple filter media layers can have different properties and use different polymer fibers. The deviation of the average fiber diameter between the two

Atty. Dkt. No. 6240.001W01 4 adjacent layers shall not exceed 5 pm when multiple filter media layers are used in the middle layer. The basis weight of the middle layer can be 20g/m² - 90g/m².

[0023] The bottom layer is made of polymeric material, and can include meltblown, electrospun nanofibers, etc. The average fiber diameter of the bottom layer can be 0.05pm - 2pm. The bottom layer can be a single filter media layer or multiple filter media layers combined; the deviation of the average fiber diameter between the two adjacent layers shall not exceed 2pm when multiple filter media layers are combined. The multiple filter media layers can have different properties and use different polymer fibers. The nanofibers can be one material or a mixture of many materials, usually PVDF, PAN, PA, etc. The meltblown can be PBT, PET, PA, PLA, etc. The basis weight of the bottom layer can be 1 g/m² - 80g/m².

[0024] The support layer can be a stiff nonwoven fabric. Examples of suitable material for the support layer include spunbond, wetlaid, carded, or melt-blown nonwoven materials, or combinations thereof. Examples of synthetic nonwovens include polyester nonwovens, nylon nonwovens, polyolefin (for example, polypropylene) nonwovens, polycarbonate nonwovens, or blended or multicomponent nonwovens thereof. Other examples of suitable support layers include polyester or bicomponent polyester fibers or polypropylene/polyethylene terephthalate, or polyethylene/polyethylene terephthalate bicomponent fibers in a spunbond.

[0025] In some embodiments, the support layer has a basis weight of at least 70 g/m², at least 100 g/m², at least 125 g/m², or at least 180 g/m². In some embodiments, the support layer has a basis weight of up to 150 g/m², up to 200 g/m², or up to 250 g/m². In an exemplary embodiment, the support layer has a basis weight in a range of 100 g/m²to 150 g/m². In another exemplary embodiment, the support layer has a basis weight in a range of 120 g/m² to 145g/m². The basis weight of the support layer may be measured using TAPPI T410 om-08.

[0026] In some embodiments, the support layer has an average mean flow pore size of at least 35 pm, at least 10 pm, at least 15 pm, at least 20 pm, or at least 25 pm. In some embodiments, the support layer has an average mean flow pore size up to 20 pm, up to 25 pm, up to 30 pm, up to 35 pm, up to 40 pm,

Atty. Dkt. No. 6240.001W01 5 up to 50 pm, up to 60 pm, up to 70 pm, up to 80 pm, or up to 90 pm. In an exemplary embodiment, the support layer has an average mean flow pore size in a range of 25 pm to 50 pm. In some embodiments, the average mean flow pore size is preferably determined using capillary flow porometry.

[0027] The top, middle, and bottom layers can comprise more than one filter media layer in each. The polymer composition and physical properties of the individual filter media layers used in the top layer, middle layer, and bottom layer can be selected for filter performance.

[0028] Meltblown fibers can be used in the filter media layers of the top, middle, and bottom layers of the composite filter media. In embodiments, polymers used in the meltblown fibers can include Polybutylene terephthalate (PBT) polyesters Suitable thermoplastic polymers for forming the meltblown fibers include, but are not limited to, polyolefins, polycondensates e.g., polyamides, polyesters, polycarbonates, and polyarylates), vinyl polymers, polyols, polydienes, polyurethanes, polyethers, polyacrylates, polycarbonates, polystyrenes, and so forth. Examples of suitable polyolefins include, by way of example only, polyethylene, polybutene and copolymers and/or blends thereof. As examples, the fibers can comprise ethylene polymers and copolymers thereof and more particularly can comprise copolymers of ethylene with alpha-olefins. Additional examples of polymers suitable for making media fibers also include poly(l -pentene), poly(2-pentene), poly(3 -methyl- 1 -pentene), poly(4-methyl-l- pentene), nylon, polybutylene, polyethylene terephthalate, polybutylene terephthalate, and so forth.

[0029] The support layer and optional protective layer can comprise a spunbond, drylaid, or wetlaid filter media. The support layers can use monocomponent or bicomponent polymers. Polymers that can be used for the support layer and protective layer include condensation polymers such as polyester (both PET and PBT), polyacetals, and polyamides, and addition polymers such as polyethylene, polytetrafluoroethylene (PTFE), and polypropylene. Polymers typically used in the construction of filters include polypropylene, polyester, and nylon. Additional polymers suitable for nonwoven filter media include higher melt-point staple fibers such as polycyclohexylenedimethylene terephthalate (PCT) and polyphenol sulfide (PPS).

Atty. Dkt. No. 6240.001W01 6 [0030] In embodiments, staple fibers can be used in one or more layers to provide structural support, spacing, and other filter performance benefits to the composite filter media. Staple fibers can include monocomponent and bicomponent materials. Staple fibers are typically short cut fibers having an average diameter of between 10 and 30 microns, and a length typically between 6 mm and 30 mm. Suitable polymers include condensation polymers such as polyester (both PET and PBT), polyacetals, and polyamides, and addition polymers such as polyethylene, polytetrafluoroethylene (PTFE), and polypropylene. Polymers typically used in the construction of such laminated filters include polypropylene, polyester, and nylon. Additional polymers suitable for nonwoven filter media include higher melt-point staple fibers such as polycyclohexylenedimethylene terephthalate (PCT) and polyphenol sulfide (PPS).

[0031] Bicomponent fiber can be made from any suitable materials including, for example, a variety of thermoplastic materials including polyolefins (such as polyethylenes, polypropylenes, etc.); polyesters (such as polyethylene terephthalate, PET, poly-butylene terephthalate, PBT, etc.); nylons (such as nylon 6, nylon 6,6, nylon 6,12, etc.). Any thermoplastic that can have an appropriate melting point can be used in the bi-component fiber while higher melting polymers can be used in the higher melting portion of the fiber. The bicomponent fiber can have, for example, a PET/PET or nylon 6/ nylon 6,6 structure with PET/components of different melting points or nylon.

[0032] Other polymer options for the fibers used in the layers of the composite filter media can be one or several combinations of the following examples, the selection of polymers includes but is not limited to the following: TPU, PVDF, nylon, PLA, PAN, PEI, Polyurethane, Polystyrene, Polyimide, Polyethylene glycol terephthalate, Polybutylene terephthalate, Nylon (Nylon-6 _s Nylon-66 _s Nylon-56 _s Nylon-1010), Polyacrylonitrile, Polyvinylidene difluoride, Poly-Vinyl Fluoride, Polytetrafluoroethylene,, Chlorotrifluoroethylene, Polyethylene oxide, Polymethyl methacrylate, Poly (m- phenyleneisophthalamide), Polysulfone, Polyphenylene sulfone resins, Polyethersulfone, Polyphenylene sulfide, Poly etherimide, Polylactic acid, Poly-1- lactide, Poly-d-lactide, Poly caprolactone, Polyvinyl alcohol, polyvinyl pyrrolidone.

Atty. Dkt. No. 6240.001W01 7 [0033] In embodiments, the individual filter media layers of the top layer can have basis weight range between 20 and 60 g/m² and a thickness between 0.15 mm and 0.4 mm. In embodiments, the fibers comprising the media layers of the top layer can have an average fiber diameter between 4 microns and 25 microns. In embodiments, the individual filter media layers can have a mean flow pore size no less than 35 microns. In other embodiments, the individual filter media layers can have a mean flow pore size between 35 and 70 microns. In embodiments, the overall basis weight of the top layer is between 20 and 100 g/m².

[0034] In some embodiments, the top layer has a basis weight of at least 20 g/m², at least 40 g/m², at least 60 g/m², or at least 70 g/m². In some embodiments, the top layer has a basis weight of up to 30 g/m², up to 50 g/m², or up to 70 g/m². In an exemplary embodiment, the top layer has a basis weight in a range of 30 g/m² to 60 g/m². In another exemplary embodiment, the top layer has a basis weight in a range of 25 g/m² to 55g/m². The basis weight of the top layer may be measured using TAPPI T410 om-08.

[0035] In some embodiments, the top layer has an average mean flow pore size of at least 35 pm, at least 45 pm, at least 50 pm, at least 55 pm, or at least 65 pm. In some embodiments, the top layer has an average mean flow pore size up to 40 pm, up to 45 pm, up to 50 pm, up to 60 pm, up to 70 pm. In an exemplary embodiment, the top layer has an average mean flow pore size in a range of 40 pm to 55 pm. In some embodiments, the average mean flow pore size is preferably determined using capillary flow porometry.

[0036] In embodiments, the individual filter media layers of the middle layer can have a basis weight range between 25 g/m² and 60 g/m² and a thickness between 0. 1 mm and 0.4 mm. In embodiments, the fibers comprising the media layers of the middle layer can have an average fiber diameter between 1 microns and 5 microns. In embodiments, the individual filter media layers can have a mean flow pore size no more than 30 microns. In other embodiments, the individual filter media layers can have a mean flow pore size between 10 and 30 microns. In embodiments, the overall basis weight of the middle layer is between 20 g/m² and 90 g/m².

[0037] In some embodiments, the middle layer has a basis weight of at least 20 g/m², at least 40 g/m², at least 60 g/m², or at least 70 g/m². In some

Atty. Dkt. No. 6240.001W01 8 embodiments, the middle layer has a basis weight of up to 30 g/m², up to 50 g/m², or up to 90 g/m². In an exemplary embodiment, the middle layer has a basis weight in a range of 50 g/m²to 90 g/m². In another exemplary embodiment, the middle layer has a basis weight in a range of 35 g/m² to 65g/m². The basis weight of the middle layer may be measured using TAPPI T410 om- 08.

[0038] In some embodiments, the middle layer has an average mean flow pore size of at least 10 pm, at least 15 pm, at least 20 pm, or at least 25 pm. In some embodiments, the middle layer has an average mean flow pore size up to 15 pm, up to 20 pm, up to 25 pm, up to 30 pm. In an exemplary embodiment, the middle layer has an average mean flow pore size in a range of 10 pm to 25 pm. In some embodiments, the average mean flow pore size is preferably determined using capillary flow porometry.

[0039] In embodiments, the individual filter media layers of the bottom layer can have a basis weight range between 5 and 50 g/m² and a thickness between 0.02 and 0.3 mm. In embodiments, the fibers comprising the media layers of the bottom layer can have an average fiber diameter between 0.05 microns and 2 microns. In embodiments, the individual filter media layers can have a mean flow pore size no more than 15 microns. In other embodiments, the individual filter media layers can have a mean flow pore size between 2 microns and 20 microns. In embodiments, the overall basis weight of the bottom layer is between 1 g/m² and 80 g/m².

[0040] In some embodiments, the bottom layer has a basis weight of at least 5 g/m², at least 15 g/m², at least 25 g/m², at least 40 g/m², at least 55 g/m², or at least 60 g/m². In some embodiments, the bottom layer has a basis weight of up to 10 g/m², up to 15 g/m², up to 30 g/m², up to 50 g/m² or up to 70 g/m². In an exemplary embodiment, the bottom layer has a basis weight in a range of 5 g/m² to 10 g/m². In another exemplary embodiment, the bottom layer has a basis weight in a range of 20 g/m² to 60 g/m². The basis weight of the bottom layer may be measured using TAPPI T410 om-08.

[0041] In some embodiments, the bottom layer has an average mean flow pore size of at least 2 pm, at least 10 pm, at least 15 pm. In some embodiments, the bottom layer has an average mean flow pore size up to 5 pm, up to 10 pm, up to 15 pm, up to 20 pm. In an exemplary embodiment, the

Atty. Dkt. No. 6240.001W01 9 botom layer has an average mean flow pore size in a range of 10 pm to 15 pm. In some embodiments, the average mean flow pore size is preferably determined using capillary flow porometry.

[0042] In embodiments, the average fiber diameter of the fibers in the middle layer is less than the average fiber diameter of the fibers in the top layer. In embodiments, the average fiber diameter of the fibers in the botom layer is less than the average fiber diameter of the fibers in the middle layer. In embodiments, the average fiber diameter of the fibers in the middle layer is less than the average fiber diameter of the fibers in the top layer, and the average fiber diameter of the fibers in the botom layer is less than the average fiber diameter of the fibers in the middle layer.

[0043] In embodiments, the mean flow pore size for the media layers in the middle layer is less than the mean flow pore size for the filter media layers in the top layer, and the mean flow pore size for the filter media layers in the botom layer is less than the mean flow pore size for the filter media layers in the middle layer. In embodiments, the mean flow pore size for the filter media layers in the middle layer is less than the mean flow pore size for the filter media layers in the top layer. In embodiments, the mean flow pore size for the filter media layers in the botom layer is less than the mean flow pore size for the filter media layers in the middle layer.

[0044] In some embodiments, the support layer has a basis weight of at least 70 g/m², at least 100 g/m², at least 125 g/m², or at least 180 g/m². In some embodiments, the support layer has a basis weight of up to 100 g/m², up to 150 g/m², or up to 250 g/m². In an exemplary embodiment, the support layer has a basis weight in a range of I50g/m²to 180 g/m². In another exemplary embodiment, the support layer has a basis weight in a range of 120 g/m² to I45g/m². The basis weight of the support layer may be measured using TAPPI T410 om-08.

[0045] In some embodiments, the support layer has an average mean flow pore size of at least 35 pm, at least 10 pm, at least 15 pm, at least 20 pm, or at least 25 pm. In some embodiments, the support layer has an average mean flow pore size of up to 10 pm, up to 15 pm, up to 20 pm, up to 25 pm, up to 30 pm, up to 35 pm, up to 40 pm, up to 50 pm, up to 60 pm, up to 70 pm, up to 80 pm, or up to 90 pm. In an exemplary embodiment, the support layer has an

Atty. Dkt. No. 6240.001W01 10 average mean flow pore size in a range of 25 pm to 50 pm. In some embodiments, the average mean flow pore size is preferably determined using capillary flow porometry.

[0046] FIG. 2 shows a cross-section view of the composite filter media 15 with top layer 16, middle layer 17, bottom layer, 18 and support layer 19. The top layer 21 uses two filter media layers 20 and 21. The middle layer can also comprise two separate filter media layers 22 and 23. Filter media layers can be selected based on their material properties including polymer type, mean flow pore size, fiber diameter, basis weight, thickness, and permeability. The filter media layers 20 and 21 of the top layer as well as the filter media layers 22 and 23 of the middle layer can have the same properties or different properties, depending on the filtration performance desired for the composite filter media. [0047] FIG. 3 shows a cross-section view of the composite filter media 30 with top layer 31, middle layer 32, bottom layer 33, and support layer 34. The bottom layer uses two filter media layers 35 and 36. Filter media layers can be selected based on their material properties including polymer type, mean flow pore size, fiber diameter, basis weight, thickness, and permeability. The filter media layers 35 and 36 of the bottom layer can have the same properties or different properties, depending on the filtration performance desired for the composite filter media.

[0048] FIG. 4 shows a cross-section view of the composite filter media 40 using a protective layer 41 arranged on top of the top layer 42, middle layer 43, bottom layer 44 and support layer 45. Filter media layers can be selected based on their material properties including polymer type, mean flow pore size, fiber diameter, basis weight, thickness, and permeability.

[0049] FIG. 5 shows a cross-section view of the composite filter media 50 using a protective layer 51 arranged on top of the top layer 52, middle layer 53, bottom layer 54 and support layer 55. Filter media layers can be selected based on their material properties including polymer type, mean flow pore size, fiber diameter, basis weight, thickness, and permeability. The top layer comprises a mixture of two different types of fibers commingled together. The two types of fiber can comprise larger and stiffer staple fibers 56 that can be deposited with smaller, finer fibers (such as meltblown fibers) 57.

Atty. Dkt. No. 6240.001W01 11 [0050] FIG. 6 shows a cross-section view of the composite filter media 60 using a protective layer 61 arranged on top of the top layer 62, middle layer 63, bottom layer 64 and support layer 65. Filter media layers can be selected based on their material properties including polymer type, mean flow pore size, fiber diameter, basis weight, thickness, and permeability. The middle layer is comprised of three individual filter media layers 66,67, and 68. The media layers 66, 67, and 68 can have the same properties or different properties, depending on the filtration performance desired for the composite filter media. The bottom layer 64 can comprise a nanofiber layer for higher efficiency filtration performance.

[0051] The composite liquid filtration material can contain a nanofiber layer in any of the top, middle, or bottom layers. In at least one embodiment, the nanofibers comprise polymers from the group of materials comprising polyurethane Polystyrene Polyimide Polyethylene glycol terephthalate Polybutylene terephthalate Poly ethersulfone Polylactic acid Thermoplastic Polyureathane Nylon (Nylon-6, Nylon-66 Nylon-56 Nylon-1010 ) Polyacrylonitriles Polyvinylidene di fluoride^ Poly-Vinyl Fluoride and/or any combination thereof.

[0052] In at least one embodiment, the nanofibers comprise fibers selected from the group consisting of electrospun needle spinning nanofibers, electrospun needleless spinning nanofibers, centrifugal force spinning nanofiber, electroblowing nanofiber, and/or any combination thereof.

[0053] In at least one embodiment, the nanofibers have a diameter less than 5 pm. In at least one embodiment, the nano fibers have a diameter less than 1 pm. In at least one embodiment, the nano fibers have a diameter less than 0.5pm. In at least one embodiment, the nanofibers can have a diameter between 0.15 pm and 0.3pm.

[0054] The nanofiber layer can comprise a blend or mixture of multicomponent nanofibers. Multicomponent nanofibers can include nanofibers with different diameters in the nanofiber layer, that is, the mixture of larger nanofibers and finer nanofibers is used to increase the void volume of the nanofiber layer, creating a more lofty structure that can maintain high filtration efficiency and also allow for higher depth loading of contaminants. Descriptions

Aty. Dkt. No. 6240.001W01 12 and examples of nanofiber layers with multicomponent nanofibers that could be used in the present disclosure are described in US Application 63/445294, “Multicomponent Composite Structure Filter Media ”, filed February 13, 2023, the entire contents of which are incorporated by reference.

[0055] The nanofiber layer can comprise multilayered nanofibers. Multilayered nanofibers can include nanofiber layers comprising one or more sets of electrospun nanofibers with an inner support layer comprising larger fibers between nanofiber layers, that is, the inner support layer is used to increase the void volume of the nanofiber layer, creating a more lofty structure that can maintain high filtration efficiency and also allow for depth loading of contaminants. Descriptions and examples of nanofiber layers with multilayered nano fibers that could be used in the present disclosure are described in US Application 63/445293, “A Composite Filter Media and Its Preparation Method”, filed February 13, 2023, the entire contents of which are incorporated by reference.

[0056] In an embodiment, the top, middle, or bottom layers can include multilayered nanofibers wherein the multilayered nanofibers comprise nanofiber layers and an inner support layer wherein the nanofiber layers includes a first distribution of fibers having an average fiber diameter between 10 nm and 200 nm; and the inner support layer includes a second distribution of fibers having an average fiber diameter of 0.3-25pm; and wherein within the plurality of multilayered nanofibers, the inner support layer is included between at least two nanofiber layers.

[0057] In an embodiment, the nanofiber layer can comprise multicomponent nanofibers wherein the large nanofibers have diameters of between 300 nm and 5 pm and wherein the fine nanofibers have diameters between 50 nm and 300nm. In another embodiment, the large nanofibers have diameters greater than 0.1pm and preferably greater than 0.3 pm, and more preferably greater than 0.5 pm, and wherein the fine nanofibers have diameters less than 0.3 pm, less than 0.2 pm, and less than lOOnm.

[0058] In some embodiments, the nanofiber layer has a basis weight of up to 1.5 g/m², up to 2 g/m², up to 2.5 g/m², up to 3 g/m², up to 3.5 g/m², up to 4 g/m², up to 4.5 g/m², up to 5 g/m², up to 10 g/m², up to 20 g/m² . In some embodiments, the nanofiber layer has a basis weight of at least 0. lg/m² and up to

Atty. Dkt. No. 6240.001W01 13 20 g/m². In another exemplary embodiment, the nanofiber layer has a basis weight of at least 2g/m² and up to lOg/m².

[0059] In embodiments, the composite fdter media is formed using materials and processes that do not significantly compress the individual material layers that comprise the composite filter media. By limiting the compression of the individual layers, the pore size and thickness ranges designed into the individual layers for optimal filtration performance can be maintained for optimal filtration performance. The top layer, middle layer, bottom layer, and support layer including any individual filter media layers that make up the top, middle, and bottom layers along with any optional protection layer can be bonded together using ultrasonic bonding, spray adhesive, and/or other bonding methods that do not significant compress the individual layers to form the composite filter media. In embodiments, the total thickness of the composite filter media is no less than 70% of the sum of the individual thicknesses of each material. In embodiments, the total thickness of the composite filter media is no less than 80% of the sum of the individual thicknesses of each material. In embodiments, the total thickness of the composite filter media is no less than 90% of the sum of the individual thicknesses of each material.

[0060] Composite filter media materials produced using the materials and methods of this disclosure have several valuable properties. The composite filter media can be relatively thin while still maintaining a high capacity for storing contaminants. In addition, the composite filter media can have a high filtration efficiency while also having low resistance to fluid flow.

[0061] In the composite filter media, the top layer, middle layer, and bottom layer form a gradient structure from top to bottom in which the average fiber diameter, the mean flow pore size, and the air permeability all decrease from the top layer to the bottom layer. In embodiments, the top layer, middle layer, and bottom layers can each include one or more individual filter media layers where the individual filter media layers form an overall gradient structure from top layer to the bottom layer in which the average fiber diameter, the mean flow pore size, and the air permeability all decrease from the top layer to the bottom layer. In embodiments, the top layer, middle layer, and bottom layers can each include one or more individual filter media layers where the individual filter media layers form an overall gradient structure from top layer to the

Aty. Dkt. No. 6240.001W01 14 bottom layer in which the average fiber diameter, the mean flow pore size, and the air permeability all decrease from the top layer to the bottom layer. In embodiments, the top layer, middle layer, and bottom layers can each include one or more individual filter media layers where the individual filter media layers form a gradient structure within each layer from top to bottom in which the average fiber diameter, the mean flow pore size, and the air permeability all decrease from the top layer to the bottom layer. The gradient structure including pore sizes, fiber diameter, thickness, air permeability, basis weight, etc. of each layer in the composite filter media can be designed to maximize filtration properties for a filtration application.

[0062] Filter media can be evaluated for liquid filtration performance using a multipass test bench under ISO 19438. The test can measure the filter media’s overall filtration efficiency for particles in a contaminant sample and the overall dust holding capacity of the filter media at a specified terminal pressure drop. Testing can be done using a variety of test dusts at different concentrations in a specific liquid such as oil, hydraulic fluid, fuel, etc. In an embodiment, the liquid tested can be No. 15 aviation hydraulic oil. In an embodiment, the liquid can contain a contaminant concentration of 100 mg/L and the contaminant can be A3 test dust as specified in ISO 12103. In an embodiment, the flow rate on the test bench can be 0.7 1/min. The terminal pressure drop for the test can vary from 50- 150 kPa. In an embodiment, the dust holding capacity and efficiency are measured after a terminal pressure drop of 100 kPa is reached on the test bench.

[0063] In an embodiment, a composite fuel filter media having a basis weight between 200 and 350g/m² and thickness between 1.0 and 1.3mm can have a particle filtration efficiency of no less than 95% for 4pm and larger particles, and dust holding capacity of no less than 200g/m². The middle layer of the composite media can comprise one or more meltblown layers each having a thickness of less than 0.4 mm and the bottom can comprise a melt blown layer having a thickness less than 0.2 mm. The layers of the composite filter media can be ultrasonically bonded.

[0064] In an embodiment, a composite fuel filter media having a basis weight between 180 and 330g/m² and thickness no greater than 1.2 mm can have a particle filtration efficiency of no less than 99% for 4pm and larger particles, and dust holding capacity of no less than 200g/m². The bottom layer of the

Aty. Dkt. No. 6240.001W01 15 composite filter media can comprise 2 or more filter media layers of meltblown fiber, each filter media layer having a thickness less than 0.3 mm. The layers of the composite filter media can be ultrasonically bonded.

[0065] In an embodiment, a composite fuel filter media having a basis weight between 250 and 350g/m² and thickness between 1.0 and 1.4 mm can have a particle filtration efficiency of no less than 90% for 4pm and larger particles, and dust holding capacity of no less than 240g/m². In an embodiment, a composite fuel filter media having a basis weight between 250 and 350g/m² and thickness between 1.0 and 1.4 mm can have a particle filtration efficiency of no less than 80% for 4pm and larger particles, and dust holding capacity of no less than 240g/m². The composite filter media can comprise a protective layer arranged above the top layer. The composite filter media can comprise a top layer of meltblown media having a thickness less than 0.5 mm and a middle layer of meltblown media having a thickness less than 0.3 mm. The layers of the composite filter media can be ultrasonically bonded.

[0066] In an embodiment, a composite fuel filter media having a basis weight between 200 and 300g/m² and thickness between 1.0 and 1.5mm can have a particle filtration efficiency of no less than 90% for 4pm and larger particles, and dust holding capacity of no less than 240g/m². In an embodiment, a composite fuel filter media having a basis weight between 200 and 300g/m² and thickness between 1.0 and 1.5 mm can have a particle filtration efficiency of no less than 80% for 4pm and larger particles, and dust holding capacity of no less than 240g/m². The composite filter media can have a top layer comprising a mixture of staple fibers and meltblown fibers. The thickness of the top layer can be less than 0.5 mm. The layers of the composite filter media can be ultrasonically bonded.

[0067] In an embodiment, a composite fuel filter media having a basis weight between 250 and 350g/m² and thickness between 1.0 and 1.4 mm can have a particle filtration efficiency of no less than 99.5 % for 4pm and larger particles, and dust holding capacity of no less than 180g/m². The bottom layer of the composite filter media can comprise a nanofiber layer. The thickness of the bottom layer can be less than 0.3 mm. The layers of the composite filter media can be ultrasonically bonded.

Atty. Dkt. No. 6240.001W01 16 [0068] In an embodiment, a composite fuel filter media having a basis weight between 200 and 350g/m² and thickness between 1.0 and 1.5 mm can have a particle filtration efficiency of no less than 80% for 4pm and larger particles, and dust holding capacity of no less than 240g/m². In an embodiment, a composite fuel filter media having a basis weight between 200 and 350g/m² and thickness between 1.0 and 1.5 mm can have a particle filtration efficiency of no less than 90% for 4pm and larger particles, and dust holding capacity of no less than 240g/m². In an embodiment, a composite fuel filter media having a basis weight between 200 and 350g/m² and thickness between 1.0 and 1.5 mm can have a particle filtration efficiency of no less than 95 % for 4pm and larger particles, and dust holding capacity of no less than 200g/m². In an embodiment, a composite fuel filter media having a basis weight between 200 and 350g/m² and thickness between 1.0 and 1.5 mm can have a particle filtration efficiency of no less than 99 % for 4pm and larger particles, and dust holding capacity of no less than 200g/m². In an embodiment, a composite fuel filter media having a basis weight between 200 and 350g/m² and thickness between 1.0 and 1.5 mm can have a particle filtration efficiency of no less than 99.5 % for 4pm and larger particles, and dust holding capacity of no less than 180g/m². In an embodiment, a composite fuel filter media having a basis weight between 200 and 350g/m² and thickness between 1.0 and 1.5 mm can have a particle filtration efficiency of no less than 99.9% for 4pm and larger particles, and dust holding capacity of no less than 180g/m². The bottom layer of the composite filter media can comprise a nanofiber layer. The composite filter media can comprise a protective layer arranged on top of the top layer. The middle layer of the composite filter media can comprise 2 or more individual meltblown media layers each having a thickness of less than 0.5 mm. The layers of the composite filter media can be ultrasonically bonded.

[0069] In some embodiments, a wire support may be located downstream of the support layer. In some embodiments, the filter media, including, for example, a filter media encompassed in a filter element, may be pleated. The filter media of the present disclosure may be manufactured into other filter elements, including flat-panel filters, cartridge filters, or other filtration components.

Atty. Dkt. No. 6240.001W01 17 [0070] An embodiment of a filter cartridge element that can use the composite filter media is shown in FIG 7. The filter element 70 has a top 71, a bottom 72, an outside surface 73, and an inlet or outlet for fluid flow 74, depending on the flow design for the filter. The composite filter media is arranged in the filter element so that the top layer of the media is oriented to the upstream side and the bottom layer of the media is oriented towards the downstream side. In filter elements with “outside-in” flow, in which the fluid is filtered as it flows from the outside of the filter element to the inside of the filter element, the top layer is oriented towards the outside surface of the filter element. In filter elements with “inside-out” flow, in which the fluid is filtered as it flows from the inside of the filter element to the outside of the filter element, the bottom layer is oriented towards the outside surface of the filter element.

[0071] As used herein, fibers having an “average” diameter indicates that in a sample of a plurality of fibers, the average fiber diameter of that population of fibers in that sample has the indicated average fiber diameter.

[0072] Fiber diameter may be measured using a top-down SEM image. The sample may be sputter-coated. A useful sputter-coater may be a gold and palladium mixture including, for example, a Au:Pd 60:40 mixture. A more accurate fiber diameter measurement may be obtained by measuring the diameter of the fiber in at least 30 locations in the sample.

[0073] As used herein, “nanofiber” can include fiber having a diameter of up to 5 micrometers (pm). In some embodiments, a fine nanofiber fiber has a diameter of at least 10 nm or at least 100 nm.

[0074] The term “diameter” refers either to the diameter of a circular cross-section of a fiber, or to a largest cross-sectional dimension of a noncircular cross-section of a fiber.

[0075] The term “particle size,” as used herein, refers to a particle's diameter, determined as described in ISO 11171 :2016.

[0076] As used herein, unless indicated otherwise, pore sizes are determined using capillary flow porometry. Capillary flow porometry may be performed using a continuous pressure scan mode. It may be useful to use silicone oil, having a surface tension of 20. 1 dynes/cm and a wetting contact angle of 0, as a wetting liquid. The sample may initially be tested dry, varying low pressure to high pressure, and then tested wet, again varying low pressure to

Atty. Dkt. No. 6240.001W01 18 high pressure. The test is typically performed at ambient temperature conditions (for example, 20° C. to 25° C.). 256 data points may be collected across the range of the scan of the pressures for both the dry curve and the wet curve. Typically, no tortuosity factor and/or a shape factor will be used (that is, for comparison to other test methods that use an adjustment factor, a factor equal to 1 may be used).

[0077] Using the capillary flow porometry test procedure, the mean flow pore size for a filter media is defined as the pore size such that 50% of the total flow through the layer is through pores of that size or below.

[0078] As used herein, “pressure drop” (also referred to herein as “dP” or “AP”) relates to the pressure (exerted by a pump) necessary to force fluid through the filter or filter medium for a particular fluid velocity. Unless otherwise indicated, pressure drop is measured as described in ISO 3968:2017. [0079] The terms “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims. Such terms will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. By “consisting of’ is meant including, and limited to, whatever follows the phrase “consisting of’ Thus, the phrase “consisting of’ indicates that the listed elements are required or mandatory, and that no other elements may be present. By “consisting essentially of’ is meant including any elements listed after the phrase, and limited to other elements that do not interfere with or contribute to the activity or action specified in the disclosure for the listed elements. Thus, the phrase “consisting essentially of’ indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present depending upon whether or not they materially affect the activity or action of the listed elements.

[0080] The words “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.

Aty. Dkt. No. 6240.001W01 19 [0081] Unless otherwise specified, “a,” “an,” “the,” and “at least one” are used interchangeably and mean one or more than one. The phrases “at least one of’ and “comprises at least one of’ followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

[0082] As used herein, the term “or” is generally employed in its usual sense including “and/or” unless the content clearly dictates otherwise. The term “and/or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0083] Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range (for example, 1 to 5 includes 1 , 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Herein, “up to” a number (for example, up to 50) includes the number (for example, 50).

[0084] For any method disclosed herein that includes discrete steps, the steps may be conducted in any feasible order. And, as appropriate, any combination of two or more steps may be conducted simultaneously.

[0085] Reference throughout this specification to “one embodiment,” “an embodiment,” “certain embodiments,” or “some embodiments,” etc., means that a particular feature, configuration, composition, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, the appearances of such phrases in various places throughout this specification are not necessarily referring to the same embodiment of the disclosure. Furthermore, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments.

[0086] Any reference to standard methods (e.g., ASTM, ISO, etc.) refer to the most recent available version of the method at the time of filing of this disclosure unless otherwise indicated.

[0087] Unless otherwise indicated, all numbers expressing quantities of components, molecular weights, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” As used herein in connection with a measured quantity, the term “about” refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring

Aty. Dkt. No. 6240.001W01 20 equipment used. Accordingly, unless otherwise indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0088] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. All numerical values, however, inherently contain a range necessarily resulting from the standard deviation found in their respective testing measurements.

[0089] All headings are used for the convenience of the reader and should not be used to limit the meaning of the text that follows the heading, unless so specified.

EXAMPLES

Example 1

[0090] PET spunbonded nonwoven fabric with a basis weight of 140g/m² was prepared as the support layer, the top layer is composed of 35g/m² PBT meltblown nonwoven fabric and 25g/m2 PBT meltblown nonwoven fabric, the average fiber diameters are 6.25 pm and 5.53 pm respectively; the middle layer is composed of 45g/m² PBT meltblown and 30g/m2 PBT meltblown nonwoven fabrics, and the average fiber diameters are 2.2pm and 1.43pm; the bottom layer is 30g/m² PA meltblown nonwoven fabric, with an average fiber diameter of 1.56 pm. The characteristics and performance data of each layer is shown in Table 1. The top layer, the middle layer, the bottom layer and the support layer obtained above are stacked from top to bottom as shown in FIG. 2. After ultrasonic bonding, the full synthetic composite fuel filter media is obtained with basis weight of 300g/m2 and thickness of 1.25 mm.

[0091] With reference to ISO9237, the air permeability of the full synthetic composite media is measured as 30L/m2/s. With reference to ISO 19438, the filtration efficiency and dust holding capacity were tested by using a multi-pass test bench equipment. The test medium is No. 15 aviation hydraulic

Atty. Dkt. No. 6240.001W01 21 oil, and the test dust is A3 dust specified in ISO 12103; The test condition is flow rate of 0.7L/min, A P is lOOKpa, oil pollution concentration is lOOmg/L. The test results show that the particle filtration efficiency is 95% @ above 4pm, and dust holding capacity is 220g/m².

Table 1 : Performance parameters of each component in Example 1

Example 2

[0092] PET spunbonded nonwoven fabric with a basis weight of 120g/m² was prepared as the support layer; the top layer is a 40g/m² PBT meltblown nonwoven fabric with an average fiber diameter of 7.35 micron; The middle layer is composed of two PBT meltblown with a basis weight of 30g/m² each, and the average fiber diameters are 1.78 micron and 1 micron; the bottom layer is 30g/m² PA meltblown nonwoven fabrics, the average fiber diameter is 1.3 micron. The characteristics and performance data of each layer is shown in Table 2. The top layer, the middle layer, the bottom layer and the support layer obtained above are stacked from top to bottom. As shown in FIG. 3. After

Aty. Dkt. No. 6240.001W01 22 ultrasonic bonding, a fully synthetic composite fuel filter media is obtained with a basis weight of 250 g/m² and a thickness of 1.05 mm.

[0093] With reference to ISO9237, the air permeability of the composite media is measured as 30L/m2/s. With reference to ISO 19438, the filtration efficiency and dust holding capacity were tested by using a multi-pass test bench equipment. The test medium is No. 15 aviation hydraulic oil, and the test dust is A3 ash specified in ISO 12103; The test condition is flow rate of 0.7L/min, A P is lOOKpa, oil pollution concentration is lOOmg/L. The test results show that the particle filtration efficiency above 4 micron is 99%, and dust holding capacity is 210g/m².

Table 2: Performance parameters of each component in Example 2

Example 3

[0094] Prepare PET spunbonded nonwoven fabric with a basis weight of 20g/m² as the protective layer, the top layer is PET spunlaced nonwoven fabric with a basis weight of 54.2g/m², and the average fiber diameter is about 8pm.

The middle layer is PBT meltblown nonwoven fabric with a basis weight of 28.6g/m², and the average fiber diameter of 2.89 pm. The bottom layer is PBT

Aty. Dkt. No. 6240.001W01 23 meltblown nonwoven fabric with a basis weight of 40g/m², and the average fiber diameter of 1.68 gm. PET spunbonded nonwoven fabric with a basis weight of 120g/m² is prepared as the support layer. The characteristics and performance data of each layer is shown in Table 3. The protective layer, the top layer, the middle layer, the bottom layer and the support layer obtained above are arranged from top to bottom as shown in FIG. 4. After ultrasonic bonding, the fully synthetic fuel filter media with a basis weight of 260g/m² and a thickness of 1.3mm is obtained.

[0095] According to ISO9237, the air permeability of the composite is measured as 30L/m2/s. With reference to ISO 19438, the filtration efficiency and dust holding capacity were tested by using a multi-pass test bench equipment. The test medium is No. 15 aviation hydraulic oil, and the test dust is A3 ash specified in ISO 12103; The test condition is flow rate of 0.7L/min, A P is lOOKpa, oil pollution concentration is lOOmg/L. The test results show that the particle filtration efficiency above 4 micron is 90%, and dust holding capacity is 250g/m².

Table 3: Performance parameters of each component in Example 3

Aty. Dkt. No. 6240.001W01 24 Example 4

[0096] Prepare PET spunbonded nonwoven fabric with a basis weight of 20g/m² as the protective layer. The top layer is PBT meltblown nonwoven fabric with a basis weight of 38g/m², and the average fiber diameter of 6.25 p m. The middle layer is PBT meltblown nonwoven fabric with a weight of 28g/m², and the average fiber diameter of 2.89 p m. the middle layer is PBT meltblown nonwoven fabric with a weight of 40g/m², and the average fiber diameter of 1.68pm. PET spunbonded nonwoven fabric with a basis weight of 120g/m2 is prepared as the support layer. The performance data of each layer is shown in Table 4. The protective layer, the top layer, the middle layer, the bottom layer and support layer obtained above are arranged from top to bottom as shown in FIG. 4. After ultrasonic bonding, the fully synthetic fuel filter media with a basis weight of 250g/m² and a thickness of 1.2mm is obtained.

[0097] According to ISO9237, the air permeability of the composite is measured as 80L/m2/s. With reference to ISO 19438, the filtration efficiency and dust holding capacity were tested by using a multi-pass test bench equipment. The test medium is No. 15 aviation hydraulic oil, and the test dust is A3 ash specified in ISO 12103; The test condition is flow rate of 0.7L/min, A P is lOOKpa, oil pollution concentration is lOOmg/L. The test results show that the particle filtration efficiency above 4 micron is 90%, and dust holding capacity is 240g/m².

Table 4: Performance parameters of each component in Example 4

Atty. Dkt. No. 6240.001W01 25

Example 5

[0098] Prepare PET spunbonded nonwoven fabric with a basis weight of 20g/m² as the protective layer, the top layer is a two-component material with a basis weight of 42.5g/m², which is mixed with coarse PET staple fiber and fine PBT melt-blown; the middle layer is 28.6g/m² PBT meltblown nonwoven fabric with the average fiber diameter of 2.89 p m. the bottom layer is 40g/m² PBT meltblown nonwoven fabric with the average fiber diameter of 1.68pm. PET spunbonded nonwoven fabric with a basis weight of 120g/m² is prepared as the support layer. The performance data of each layer is shown in Table 5. The protective layer, the top layer, the middle layer, the bottom layer and support layer obtained above are arranged from top to bottom as shown in FIG. 5. After ultrasonic bonding, the fully synthetic fuel filter media with a basis weight of 250g/m² and a thickness of 1.2mm is obtained.

[0099] According to ISO9237, the air permeability of the composite is measured as 70L/m2/s. With reference to ISO 19438, the filtration efficiency and dust holding capacity were tested by using a multi-pass test bench equipment. The test medium is No.15 aviation hydraulic oil, and the test dust is A3 ash specified in ISO 12103; The test condition is flow rate of 0.7L/min, A P is lOOKpa, oil pollution concentration is lOOmg/L. The test results show that the particle filtration efficiency above 4 micron is 90%, and dust holding capacity is 250g/m².

Table 5: Performance parameters of each component in Example 5

Atty. Dkt. No. 6240.001W01 26

Example 6

[00100] Prepare PET spunbonded nonwoven fabric with a basis weight of 20g/m² as the protective layer. The top layer is PBT meltblown nonwoven fabric with a weight of 25g/m², and the average fiber diameter is 5.90 pm. The middle layer is composed of three layers of meltblown, which are 30g/m² PBT meltblown with the average fiber diameter is 1.7 p m ; 30g/m² PBT meltblown with an average fiber diameter of 0.88 p m; 30g/m² PBT meltblown with an average fiber diameter of 1.3 p m. The bottom layer is designed as electrospun nanofiber layer, and the average diameter of nanofiber is 0.5 p m. The performance data of each layer is shown in Table 6. Prepare PET spunbonded non-woven fabric with a weight of 120g/m² as the support layer.

[00101] The protective layer, the top layer, the middle layer, the bottom layer and support layer obtained above are stacked in order from top to bottom, and then compounded by ultrasonic composite process to finally obtain a fully synthetic oil filter material with a weight of 250 g/m² and a thickness of 1. 1 mm. [00102] According to ISO9237, the air permeability of the composite is measured as 10L/m2/s. With reference to ISO 19438, the filtration efficiency and dust holding capacity were tested by using a multi-pass test bench equipment. The test medium is No. 15 aviation hydraulic oil, and the test dust is A3 ash specified in ISO 12103; The test condition is flow rate of 0.7L/min, A P is lOOKpa, oil pollution concentration is lOOmg/L. The test results show that the particle filtration efficiency above 4 microns is 99.9%, and dust holding capacity is 200g/m².

Atty. Dkt. No. 6240.001W01 27 Table 6: Performance parameters of each component in Example 6

[00103] Additional Embodiments of the composite filter media are listed below:

Embodiment 1

[00104] A composite filter media for filtering liquids comprising a. A top layer comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size above 35 microns and the polymer fibers have an average fiber diameter between 4 and 25 microns b. A middle layer arranged below the top layer and comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size no greater than 35 microns and the polymer fibers have an average fiber diameter between 1 um and 5 microns c. A bottom layer arranged below the middle layer and comprising a

Atty. Dkt. No. 6240.001W01 28 polymeric material of polymer fibers wherein the material has a mean flow pore size no greater than 15 microns and the polymer fibers have an average fiber diameter between 0.05 um and 2 microns; and d. A support layer having a basis weight no less than 70 grams per square meter arranged below the bottom layer, the support layer comprising a polymeric material comprising polymer fibers with an average fiber diameter no less than 15 microns; wherein the composite filter media is substantially free of glass fiber and has an overall thickness no more than 2 mm and an overall basis weight no less than 200 grams per square meter.

Embodiment 2

[00105] The composite filter media of Embodiment 1 wherein the average fiber diameter for the polymer fibers in the middle layer is less than the average fiber diameter for the fibers in the top layer and the average fiber diameter for the polymer fibers in the bottom layer is less than the average fiber diameter for the fibers in the middle layer.

Embodiment 3

[00106] The composite filter media of Embodiment 1 where the middle layer comprises a meltblown polymer layer having a basis weight between 25 and 35 grams per square meter and a thickness between 0. 15 and 0.2 mm.

Embodiment 4

[00107] The composite filter media of Embodiment 1 where the middle layer comprises a plurality of meltblown polymer layers, each meltblown layer having a basis weight between 25 and 35 grams per square meter and a thickness between 0. 1 and 0.3 mm.

Embodiment 5

[00108] The composite media of Embodiment 1 wherein the bottom layer comprises a meltblown polymer layer having a thickness between 0.2 and 0.4 mm and an average fiber diameter of greater than 1 micron.

Aty. Dkt. No. 6240.001W01 29 Embodiment 6

[00109] The composite filter media of Embodiment 1 wherein the bottom layer comprises a nanofiber layer wherein the average fiber diameter of the nanofiber layer is between 0.3 and 0.7 microns.

Embodiment 7

[00110] The composite filter media of Embodiment 1 wherein the top layer comprises a meltblown polymer layer having an average fiber diameter of less than 10 microns.

Embodiment 8

[00111] The composite filter media of Embodiment 1 wherein the top layer comprises a mixture of staple fibers and meltblown fibers wherein the average fiber diameter of the staple fibers is at least two times larger than the average fiber diameter of the meltblown fibers.

Embodiment 9

[00112] The composite filter media of Embodiment 1 wherein the filter media has an efficiency no less than 90% for 0.4um and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 10

[00113] The composite filter media of Embodiment 1 wherein the filter media has an efficiency no less than 99% for 0.4um and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 11

[00114] A composite filter media for filtering liquids comprising a) A top layer comprising a polymeric material of polymer fibers wherein the top layer has a basis weight between 20 and 100 grams per square meter and the polymer fibers have an average fiber

Atty. Dkt. No. 6240.001W01 30 diameter between 4 um and 20 microns; b) A middle layer arranged below the top layer and comprising a polymeric material of polymer fibers wherein the middle layer has a basis weight between 20 and 90 grams per square meter and the polymer fibers have an average fiber diameter less than the average fiber diameter of the polymer fibers of the top layer; c) A bottom layer arranged below the middle layer and comprising a polymeric material of polymer fibers wherein the bottom layer has a basis weight between 20 and 60 grams per square meter and the polymer fibers have an average fiber diameter less than the average fiber diameter of the polymer fibers of the middle layer; and d) A polymeric support layer having a basis weight no less than 70 grams per square meter arranged below the bottom layer and comprising polymer fibers having an average fiber diameter no less than 15 microns; wherein the composite filter media is substantially free of glass fiber and has an overall thickness no more than 2 mm and an overall basis weight no less than 200 grams per square meter.

Embodiment 12

[00115] The composite filter media of Embodiment 11 wherein the middle layer comprises a polymeric material having a mean flow pore size less than 35 microns, the bottom layer comprises a polymeric material having a mean flow pore size less than 15 microns, and the mean flow pore size of the polymeric material in the bottom layer is less than the mean flow pore size of the polymeric material in the middle layer.

Embodiment 13

[00116] The composite filter media of Embodiment 11 where the middle layer comprises a meltblown polymer layer having an average fiber diameter between 1 and 5 microns and a thickness between 0.15 and 0.2 mm.

Embodiment 14

Aty. Dkt. No. 6240.001W01 31 [00117] The composite filter media of Embodiment 11 where the middle layer comprises a plurality of meltblown polymer layers, each meltblown layer having an average fiber diameter between 0.8 and 5 microns and a thickness between 0. 1 and 0.3 mm.

Embodiment 15

[00118] The composite media of Embodiment 11 wherein the bottom layer comprises a meltblown polymer layer having a thickness between 0.2 and 0.4 mm and an average fiber diameter of greater than 1 micron.

Embodiment 16

[00119] The composite filter media of Embodiment 11 wherein the bottom layer comprises a nanofiber layer wherein the average fiber diameter of the nanofiber layer is between 0.3 and 0.7 microns.

Embodiment 17

[00120] The composite filter media of Embodiment 11 wherein the top layer comprises a meltblown polymer layer having an average fiber diameter of less than 10 microns.

Embodiment 18

[00121] The composite filter media of Embodiment 11 wherein the top layer comprises a mixture of polymeric staple fibers and polymeric meltblown fibers wherein the average fiber diameter of the staple fibers is at least two times larger than the average fiber diameter of the meltblown fibers.

Embodiment 19

[00122] The composite filter media of Embodiment 11 wherein the filter media has an efficiency no less than 90% for 0.4um and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 20

Atty. Dkt. No. 6240.001W01 32 [00123] The composite filter media of Embodiment 11 wherein the filter media has an efficiency no less than 99% for 0.4um and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 21

[00124] A composite filter media for filtering liquids comprising a) A top layer comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size above 35 microns and the polymer fibers have an average fiber diameter between 5 and 20 microns b) A middle layer arranged below the top layer and comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size no greater than 35 microns and the polymer fibers have an average fiber diameter between 1 um and 5 microns c) A bottom layer arranged below the middle layer and comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size no greater than 15 microns and the polymer fibers have an average fiber diameter between 0.1 um and 2 microns; and d) A support layer having a basis weight no less than 70 grams per square meter arranged below the bottom layer, the support layer comprising a polymeric material comprising polymer fibers with an average fiber diameter no less than 15 microns; wherein the composite filter media is substantially free of glass fiber and has an overall thickness no more than 2 mm and an overall basis weight no less than 180 grams per square meter.

Embodiment 22

[00125] The composite filter media of Embodiment 21 wherein the average fiber diameter for the polymer fibers in the middle layer is less than the average fiber diameter for the fibers in the top layer and the average fiber diameter for the polymer fibers in the bottom layer is less than the average fiber diameter for the fibers in the middle layer.

Aty. Dkt. No. 6240.001W01 33 Embodiment 23

[00126] The composite filter media of Embodiment 21 where the middle layer comprises a meltblown polymer layer having a basis weight between 25 and 35 grams per square meter and a thickness between 0. 15 and 0.2 mm.

Embodiment 24

[00127] The composite filter media of Embodiment 21 where the middle layer comprises a plurality of meltblown polymer layers, each meltblown layer having a basis weight between 25 and 35 grams per square meter and a thickness between 0. 1 and 0.3 mm.

Embodiment 25

[00128] The composite media of Embodiment 1 wherein the bottom layer comprises a meltblown polymer layer having a thickness between 0.1 and 0.3 mm and an average fiber diameter of greater than 0.5 micron.

Embodiment 26

[00129] The composite filter media of Embodiment 21 wherein the bottom layer comprises a nanofiber layer comprising multicomponent nanofibers of large and fine nano fibers wherein the average fiber diameter of the large nanofibers is between 0.4 and 3 microns and the average fiber diameter of the fine nanofibers is between 0.1 and 0.3 microns.

Embodiment 27

[00130] The composite filter media of Embodiment 21 wherein the top layer comprises a meltblown polymer layer having an average fiber diameter of less than 10 microns.

Embodiment 28

[00131] The composite filter media of Embodiment 21 wherein the top layer comprises a mixture of staple fibers and meltblown fibers wherein the average fiber diameter of the staple fibers is at least two times larger than the average fiber diameter of the meltblown fibers.

Atty. Dkt. No. 6240.001W01 34 Embodiment 29

[00132] The composite filter media of Embodiment 21 wherein the filter media has an efficiency no less than 70% for 4mm and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 30

[00133] The composite filter media of Embodiment 21 wherein the filter media has an efficiency no less than 80% for 4mm and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 31

[00134] A composite filter media for filtering liquids comprising a) A top layer comprising a polymeric material of polymer fibers wherein the top layer has a basis weight between 20 and 100 grams per square meter and the polymer fibers have an average fiber diameter between 5 um and 20 microns; b) A middle layer arranged below the top layer and comprising a polymeric material of polymer fibers wherein the middle layer has a basis weight between 20 and 80 grams per square meter and the polymer fibers have an average fiber diameter less than the average fiber diameter of the polymer fibers of the top layer; c) A bottom layer arranged below the middle layer and comprising a polymeric material of polymer fibers wherein the bottom layer has a basis weight between 20 and 60 grams per square meter and the polymer fibers have an average fiber diameter less than the average fiber diameter of the polymer fibers of the middle layer; and d) A polymeric support layer having a basis weight no less than 70 grams per square meter arranged below the bottom layer and comprising polymer fibers having an average fiber diameter no less than 15 microns;

Atty. Dkt. No. 6240.001W01 35 wherein the composite filter media is substantially free of glass fiber and has an overall thickness no more than 2 mm and an overall basis weight no less than 180 grams per square meter.

Embodiment 32

[00135] The composite filter media of Embodiment 31 wherein the middle layer comprises a polymeric material having a mean flow pore size less than 35 microns, the bottom layer comprises a polymeric material having a mean flow pore size less than 15 microns, and the mean flow pore size of the polymeric material in the bottom layer is less than the mean flow pore size of the polymeric material in the middle layer.

Embodiment 33

[00136] The composite filter media of Embodiment 31 where the middle layer comprises a meltblown polymer layer having a basis weight between 30 and 60 grams per square meter, an average fiber diameter between 1 and 5 microns, and a thickness between 0. 15 and 0.2 mm.

Embodiment 34

[00137] The composite filter media of Embodiment 31 where the middle layer comprises a plurality of meltblown polymer layers, each meltblown layer having an average fiber diameter between 0.8 and 5 microns and a thickness between 0. 1 and 0.3 mm.

Embodiment 35

[00138] The composite media of Embodiment 31 wherein the bottom layer comprises a meltblown polymer layer having a thickness between 0.1 and 0.3 mm and an average fiber diameter of greater than 0.5 micron.

Embodiment 36

[00139] The composite filter media of Embodiment 31 wherein the bottom layer comprises a nanofiber layer comprising multicomponent nanofibers of large and fine nano fibers wherein the average fiber diameter of the large

Atty. Dkt. No. 6240.001W01 36 nanofibers is between 0.4 and 3 microns and the average fiber diameter of the fine nanofibers is between 0.1 and 0.3 microns.

Embodiment 37

[00140] The composite filter media of Embodiment 31 wherein the top layer comprises a meltblown polymer layer having an average fiber diameter of less than 10 microns.

Embodiment 38

[00141] The composite filter media of Embodiment 31 wherein the top layer comprises a mixture of polymeric staple fibers and polymeric meltblown fibers wherein the average fiber diameter of the staple fibers is at least two times larger than the average fiber diameter of the meltblown fibers.

Embodiment 39

[00142] The composite filter media of Embodiment 11 wherein the filter media has an efficiency no less than 90% for 4mm and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 40

[00143] The composite filter media of Embodiment 31 wherein the filter media has an efficiency no less than 99% for 4mm and larger particles and a dust holding capacity no less than 200 grams per square media when tested under ISO 19438.

Embodiment 41

[00144] The composite filter media of any of the previous Embodiments wherein the bottom layer comprises a plurality of multilayered nanofibers wherein the multilayered nanofibers comprise nanofiber layers and an inner support layer wherein the nanofiber layers includes a first distribution of fibers having an average fiber diameter between 10 nm and 300 nm; and the inner support layer includes a second distribution of fibers having an average fiber

Aty. Dkt. No. 6240.001W01 37 diameter of 0.3-25pm; and wherein within the plurality of multilayered nanofibers, a support layer is included between at least two nanofiber layers. [00145] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more Aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

[00146] Although an overview of the inventive subject matter has been described with reference to specific example embodiments, various modifications and changes may be made to these embodiments without departing from the broader scope of embodiments of the present disclosure. Such embodiments of the inventive subject matter may be referred to herein, individually or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single disclosure or inventive concept if more than one is, in fact, disclosed.

[00147] The embodiments illustrated herein are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed. Other embodiments may be used and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. The Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the

Aty. Dkt. No. 6240.001W01 38 appended claims, along with the full range of equivalents to which such claims are entitled.

[00148] As used herein, the term “or” may be construed in either an inclusive or exclusive sense. Moreover, plural instances may be provided for resources, operations, or structures described herein as a single instance. Additionally, boundaries between various resources, operations, modules, engines, and data stores are somewhat arbitrary, and particular operations are illustrated in a context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within a scope of various embodiments of the present disclosure. In general, structures and functionality presented as separate resources in the example configurations may be implemented as a combined structure or resource. Similarly, structures and functionality presented as a single resource may be implemented as separate resources. These and other variations, modifications, additions, and improvements fall within a scope of embodiments of the present disclosure as represented by the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

[00149] The foregoing description, for the purpose of explanation, has been described with reference to specific example embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the possible example embodiments to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The example embodiments were chosen and described in order to best explain the principles involved and their practical applications, to thereby enable others skilled in the art to best utilize the various example embodiments with various modifications as are suited to the particular use contemplated.

[00150] It will also be understood that, although the terms “first,” “second,” and so forth may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first contact could be termed a second contact, and, similarly, a second contact could be termed a first contact, without departing from the scope of the present example embodiments. The first contact and the second contact are both contacts, but they are not the same contact.

Atty. Dkt. No. 6240.001W01 39 [00151] The terminology used in the description of the example embodiments herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used in the description of the example embodiments and the appended examples, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[00152] As used herein, the term “if’ may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.

Aty. Dkt. No. 6240.001W01 40

Claims

Claims We claim:

1. A composite filter media for filtering liquids, comprising: a. a top layer comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size above 35 microns and the polymer fibers have an average fiber diameter between 4 microns and 25 microns; b. a middle layer arranged below the top layer and comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size no greater than 35 microns and the polymer fibers have an average fiber diameter between 1 micron and 5 microns; c. a bottom layer arranged below the middle layer and comprising a polymeric material of polymer fibers wherein the material has a mean flow pore size no greater than 15 microns and the polymer fibers have an average fiber diameter between 0.05 microns and 2 microns; and d. a support layer having a basis weight no less than 70 grams per square meter arranged below the bottom layer, the support layer comprising a polymeric material comprising polymer fibers with an average fiber diameter no less than 15 microns; wherein the composite filter media is substantially free of glass fiber and has an overall thickness no more than 2 mm and an overall basis weight no less than 180 grams per square meter.

2. The composite filter media of claim 1, wherein the average fiber diameter for the polymer fibers in the middle layer is less than the average fiber diameter for the fibers in the top layer and the average fiber diameter for the polymer fibers in the bottom layer is less than the average fiber diameter for the fibers in the middle layer.

3. The composite filter media of claim 1 wherein the middle layer comprises a meltblown polymer layer having an average basis weight between 20 and 90 grams per square meter and a thickness between 0. 10 and 0.40 mm.

4. The composite filter media of claim 1, wherein the middle layer comprises a plurality of meltblown polymer layers, each meltblown layer having a basis weight between 1 and 80 grams per square meter and a thickness between 0.10 and 0.35 mm.

5. The composite media of claim 1, wherein the bottom layer comprises a meltblown polymer layer having a thickness between 0.1 and 0.3 mm and an average fiber diameter of greater than 0.5 micron.

6. The composite filter media of claim 1, wherein the bottom layer comprises a nanofiber layer wherein the nanofiber layer comprises multicomponent nanofibers of larger and finer nanofibers wherein the larger nanofibers have an average fiber diameter between 0.4 microns and 3 microns and the finer nanofibers have an average fiber diameter between 0.1 micron and 0.3 micron.

7. The composite filter media of claim 1, wherein the top layer comprises a meltblown polymer layer having an average fiber diameter of less than 10 microns.

8. The composite filter media of claim 1, wherein the top layer comprises a mixture of staple fibers and meltblown fibers wherein the average fiber diameter of the staple fibers is at least two times larger than the average fiber diameter of the meltblown fibers.

9. The composite filter media of claim 1, wherein the filter media has an efficiency no less than 70% for 4mm and larger particles and a dust holding capacity no less than 150 grams per square media when tested under ISO 19438.

10. The composite filter media of claim 1, wherein the filter media has an efficiency no less than 80% for 4mm and larger particles and a dust holding capacity no less than 150 grams per square media when tested under ISO 19438.

11. A composite filter media for filtering liquids, comprising:

Atty. Dkt. No. 6240.001W01 42 a. a top layer comprising a polymeric material of polymer fibers wherein the top layer has a basis weight between 20 and 100 grams per square meter and the polymer fibers have an average fiber diameter between 4 micron and 25 microns; b. a middle layer arranged below the top layer and comprising a polymeric material of polymer fibers wherein the middle layer has a basis weight between 20 and 90 grams per square meter and the polymer fibers have an average fiber diameter less than the average fiber diameter of the polymer fibers of the top layer; c. a bottom layer arranged below the middle layer and comprising a polymeric material of polymer fibers wherein the bottom layer has a basis weight between 1 and 80 grams per square meter and the polymer fibers have an average fiber diameter less than the average fiber diameter of the polymer fibers of the middle layer; and d. a polymeric support layer having a basis weight no less than 70 grams per square meter arranged below the bottom layer and comprising polymer fibers having an average fiber diameter no less than 15 microns; wherein the composite filter media is substantially free of glass fiber and has an overall thickness no more than 2 mm and an overall basis weight no less than 180 grams per square meter.

12. The composite filter media of claim 11, wherein the middle layer comprises a polymeric material having a mean flow pore size less than 35 microns, the bottom layer comprises a polymeric material having a mean flow pore size less than 15 microns, and the mean flow pore size of the polymeric material in the bottom layer is less than the mean flow pore size of the polymeric material in the middle layer.

13. The composite filter media of claim 11, wherein the middle layer comprises a meltblown polymer layer having an average fiber diameter between 1 and 5 microns, a basis weight up to 40 grams per square meter, and a thickness between 0.10 and 0.40 mm.

Atty. Dkt. No. 6240.001W01 43

14. The composite filter media of claim 11, wherein the middle layer comprises a plurality of meltblown polymer layers, each meltblown layer having an average fiber diameter between 1 and 5 microns and a thickness between 0. 1 and 0.35 mm.

15. The composite media of claim 11, wherein the bottom layer comprises a meltblown polymer layer having a thickness between 0.1 and 0.3 mm and an average fiber diameter of greater than 0.5 micron.

16. The composite filter media of claim 11, wherein the bottom layer comprises a nanofiber layer wherein the average fiber diameter of the nanofiber layer is between 0.1 and 0.7 microns.

17. The composite filter media of claim 11, wherein the bottom layer comprises a nanofiber layer wherein the nanofiber layer comprises multicomponent nanofibers of larger and finer nanofibers wherein the larger nanofibers have an average fiber diameter between 0.4 microns and 3 microns and the finer nanofibers have an average fiber diameter between 0. 1 micron and 0.3 micron.

18. The composite filter media of claim 11 wherein the bottom layer comprises a plurality of multilayered nanofibers wherein the multilayered nanofibers comprise nanofiber layers and an inner support layer wherein the nanofiber layers includes a first distribution of fibers having an average fiber diameter between 10 nm and 300 nm; wherein the inner support layer includes a second distribution of fibers having an average fiber diameter of 0.3-25pm; and wherein within the plurality of multilayered nanofibers, a support layer is included between at least two nanofiber layers.

19. The composite filter media of claim 11, wherein the top layer comprises a meltblown polymer layer having an average fiber diameter of less than 10 microns.

Atty. Dkt. No. 6240.001W01 44

20. The composite filter media of claim 11, wherein the top layer comprises a mixture of polymeric staple fibers and polymeric meltblown fibers wherein the average fiber diameter of the staple fibers is at least two times larger than the average fiber diameter of the meltblown fibers.

21. The composite filter media of claim 11 , wherein the filter media has an efficiency no less than 70% for 4mm and larger particles and a dust holding capacity no less than 150 grams per square media when tested under ISO 19438.

22. The composite filter media of claim 11, wherein the filter media has an efficiency no less than 80% for 4mm and larger particles and a dust holding capacity no less than 150 grams per square media when tested under ISO 19438.

Atty. Dkt. No. 6240.001W01 45