System for manufacturing nanoparticle bonded filter media

Abstract

Systems, devices, and methods are provided for producing a product (e.g., a gas or liquid filter) that includes a filter media. The system includes a feeder for advancing a substrate comprising fibers from an upstream end to a downstream end and a dispersion device for dispersing nanoparticles into the substrate as the substrate is advanced by the feeder to form a filter media. The system also includes a container for receiving the nanoparticle clusters and a feed system for transporting the nanoparticle clusters from the container to the dispersion device. The feed system is particularly suitable for introducing nanoparticles into a continuous manufacturing process at a controlled flow rate. The system simultaneously delivers and lifts nanoparticles, allowing the manufacture of filter media with improved quality and yield as well as reduced cost and time. In addition, the system is scalable and produces filter media with less discrepancy.

Description

Cross Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 585,693, filed September 27, 2023, the entire disclosure of which is incorporated herein by reference for all purposes. TECHNICAL FIELD

[0002] The present specification generally relates to systems and methods for manufacturing products containing filtration media, such as gas or liquid filters, that incorporate nanoparticles into the filtration media. BACKGROUND

[0003] Filtration media is particularly useful in capturing contaminants in filtration devices due to the fine size of the fibers. The fibers of the filtration media are measured in microns and can be formed by spunbond, meltblown, electrospinning, or other techniques. As fluid flows through the filtration media, the fine fibers capture and entrap contaminants in the filtration media.

[0004] Contaminants range widely in size. However, contaminants smaller than 1 micron are the most harmful particles to the human body and are relatively difficult to filter. For example, traditional mechanical air filters typically report a MERV rating of the fibrous filtration material to be about 8-10. As such, these filtration media do not typically capture sub-micron particles, such as viruses and other harmful pathogens.

[0005] The filtration industry has focused on two different methods of capturing these sub-micron particles: electrostatic forces and the use of nanoparticles in the filtration media. Electrostatic filters are formed by electrostatically charging the fibers within the filtration media through the use of triboelectric methods, corona discharge, hydroelectric charging, electrospun fibers, or other known methods. Electrostatic filters are most effective at capturing sub-micron particles, are fairly effective at capturing 1 to 3 micron particles, and are least effective at capturing larger particles of 3 to 10 microns. Electrostatic fibers are commonly used in many filtration applications, such as masks and high efficiency filters, to filter sub-micron contaminants, such as viruses and the like.

[0006] Another method of capturing sub-micron contaminants is the use of nanoparticles in conjunction with the fibers. Filtration systems can employ filtration media that includes larger fibers measured in microns and smaller nanoparticles. The nanoparticles increase the surface area in the media for capturing particles by reducing the overall fiber size in the media. The nanoparticles also tend to pack against each other, thereby increasing the packing density within the filtration media. It has been shown that even a small amount of nanosized fibers in a layer formed on a microfibrous material improves the filtration properties of the material.

[0007] The most common method of incorporating nanoparticles into filtration media is by electrospinning a very thin, continuous layer of nanoparticles onto a fibrous substrate. The nanoparticles typically extend parallel or perpendicular to the surface of the bulk filtration media layer and provide high efficiency filtration of small particles in addition to the filtration of larger particles provided by the coarse filtration media. For example, U.S. Patent No. 6,743,273 discloses a filtration media in which a continuous layer of nanofibers is deposited on the surface of a substrate. U.S. Patent No. 10,799,820 also discloses an air filtration media comprising a continuous layer of nanofibers on the surface of a filtration media.

[0008] While existing filtration media incorporating nanoparticles improves the relative efficiency of these filters, the commercial potential of these filters is still limited in certain applications because the nanoparticles are typically dispersed on the surface of the filtration media. The thin layer of nanoparticles on the surface of the filter provides only limited particle filtration and has a low dust holding capacity.

[0009] While many attempts have been made to incorporate nanomaterials into filtration media to improve overall filtration efficiency, these attempts have been limited to so-called “wet-laid” methods. These wet-laid methods involve incorporating chopped nanomaterials into a liquid slurry to separate the entangled nanomaterials with the help of surfactants. For example, U.S. Patent No. 10,252,201 discloses a filtration media made from a mixture of chopped nanomaterials and chopped coarse fibers formed by a wet-laid method. Similarly, U.S. Patent Application No. 2021 / 0023813 discloses a method of making a composite structure composed of a continuous nonwoven substrate with discontinuous fibers, such as carbon nanoparticles. The method includes drawing the continuous fiber nonwoven substrate through a slurry of discontinuous fibers during which the nanomaterials are embedded into the nonwoven substrate.

[0010] While these structures have shown improved efficiency, they still suffer from other problems such as reduced longevity and / or efficiency as the media is subjected to normal use conditions. Furthermore, these wet-laid methods have not successfully incorporated the nanoparticles uniformly throughout the nonwoven material, which results in clumping of the nanoparticles within the material, further reducing its efficiency and overall dust holding capacity. SUMMARY

[0011] The following presents a simplified summary of the claimed subject matter to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview of the claimed subject matter. It is not intended to identify key or critical elements of the claimed subject matter or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts of the claimed subject matter in a simplified form as a prelude to the more detailed description that is presented later.

[0012] Systems, apparatus, and methods for manufacturing products comprising filter media are provided. The filter media may include a substrate, such as a sheet, layer, membrane, open-cell membrane, mesh, reticulate material, or other media. The substrate may include fibers and nanoparticles incorporated into at least a portion of the fibers.

[0013] In one aspect, a system for manufacturing filter media is provided. The system includes a feeder for advancing a fiber-containing substrate from an upstream end to a downstream end and a dispersion device for dispersing nanoparticles into the substrate to form the filter media as the substrate is advanced by the feeder. The system also includes a container for receiving clusters of nanoparticles and a feeding system for conveying the nanoparticle clusters from the container to the dispersion device.

[0014] The feed system is particularly suitable for introducing nanoparticles into continuous manufacturing processes at a controlled flow rate (i.e., the amount, volume, or total mass of nanoparticles passing through the feed system per unit time). The feed system is configured to separate and / or break down nanoparticle clusters into smaller nanoparticle aggregates or individual nanoparticles that can be dispersed into a substrate. Furthermore, the feed system delivers nanoparticles to a dispersion device at a controlled rate or controlled volumetric flow rate, allowing them to be transported to filter manufacturing equipment to form filter media with improved quality and yield, and reduced cost and time. Additionally, the system is scalable and produces filter media with minimal variation.

[0015] In this implementation, the feeding system delivers the desired amount, volume, or mass of nanoparticles at a rate substantially consistent with the rate at which the feeder advances the substrate from upstream to downstream. This ensures that a substantially constant amount, mass, or volume of nanoparticles is dispersed throughout the substrate or sub-regions, allowing the system to produce a relatively uniform filter medium and reducing variability between filter media. The specific rate at which the nanoparticles are dispersed into the substrate will depend on the desired specifications of the final filtered product, such as the preferred mass, volume, or amount of nanoparticles dispersed within the volume or square area of ​​the filter medium. In an exemplary implementation, the nanoparticles are dispersed into the moving substrate at a rate of approximately 0.1 g / m² to approximately 10 g / m², but it should be understood that this rate can vary depending on the specifications of the final product.

[0016] In this implementation, the feeding system includes a lift coupled to a container for raising the nanoparticles from a first height within the container to a second height greater than the first. Nanoparticles are essentially weightless and readily suspended in the air, making their transport and / or lifting more difficult. Furthermore, the mechanical properties of nanoparticles do not allow them to fall freely within tanks or containers for transport. Instead, nanoparticles tend to stick together and clump, resulting in agglomeration at any type of opening. The lift described herein continuously and efficiently transports and lifts nanoparticles from containers or bulk silos to manufacturing equipment without compressing and compacting individual nanoparticles together.

[0017] In one embodiment, the lifter includes an outer tube having a plurality of discs configured to move through the tube. Preferably, the outer diameter of the discs allows them to move through the tube while limiting the amount of space between the inner wall of the tube and the outer surface of the discs. Thus, the discs define internal compartments within the tube for containing and transporting clusters of nanoparticles.

[0018] The disc can be transported through the pipe in any suitable manner. In one embodiment, the lift includes a cable coupled to the disc and a motor or other energy source coupled to the cable to translate the cable and disc through the pipe. In other embodiments, the disc can be driven by pneumatic, electrical, magnetic, mechanical, or other suitable energy sources.

[0019] The tube preferably includes one or more openings to allow nanoparticle clusters to enter and exit compartments between the discs as the discs move through the tube. This allows a lifter to transport the nanoparticle clusters from the container to the dispersion device. At least one opening is located above the tube to allow nanoparticles to fall into the compartments, and at least one opening is located below the tube to allow nanoparticles to fall out of the compartments. Alternatively, the tube may include a rotatable internal section such that the compartments can be rotated from one direction to another as the discs advance through the tube.

[0020] At least a portion of the tube may extend at an angle transverse to the vertical axis of the system to move nanoparticles from a first height to a second height. In some embodiments, at least a portion of the tube extends substantially parallel to the vertical axis.

[0021] In the implementation, the container includes a bulk bin configured to open, separate, and / or break down larger or bulky clusters / clumps of nanoparticles into smaller clusters or individual nanoparticles. It should be recognized that nanoparticles can be introduced into the bulk bin in a variety of different forms. For example, large clusters of nanoparticles can be partially or completely broken up before being introduced into the bulk bin, and / or they can be completely broken up and separated within the bulk bin.

[0022] In one embodiment, the bulk hopper includes one or more rotors disposed inside the hopper. Each rotor includes one or more rotating blades for mechanically separating large clusters of nanoparticles into smaller clusters of nanofibers or individual nanoparticles. The blades also serve to sweep the nanoparticles downwards through the bulk hopper and into a collecting container.

[0023] In one embodiment, the rotors are configured to rotate about an axis tangential to the height of the container, such that the blades convey the nanoparticles downward through the container to the lower vessel and the lift. In a preferred embodiment, at least some rotors rotate clockwise and at least some rotors rotate counterclockwise. In some embodiments, the bulk hopper may include one or more rows of such rotors. In an exemplary embodiment, the bulk hopper includes a second lower row of rotors for sweeping the nanoparticles off the sidewalls of the bulk hopper.

[0024] In one embodiment, the system further includes a collecting vessel located below the opening of the bulk hopper for moving nanoparticles from the bulk hopper to an elevator. In a preferred embodiment, the vessel is shaped to control the volumetric flow rate of the nanoparticles. In one such embodiment, the vessel is substantially funnel-shaped, with its lower opening having a smaller cross-sectional area than its upper opening.

[0025] In one embodiment, the feeding system includes at least one feed hopper or bin disposed between the elevator and the dispersion device. The feed hopper includes one or more mechanisms for controlling the volumetric flow rate of nanoparticles passing through it. In one embodiment, at least one of these mechanisms propels the nanoparticles in a substantially horizontal direction through the feed hopper and into the dispersion device. In an exemplary embodiment, the device includes a helical conveyor comprising one or more curved blades for redirecting the flow of nanoparticles from a vertical direction to a horizontal direction and for controlling the volumetric flow rate of the nanoparticles from the feed hopper to the filter media manufacturing equipment.

[0026] In one embodiment, the filter media manufacturing apparatus includes a first device for separating and / or isolating nanoparticles in a gaseous medium and a second device for combining the nanoparticles with fibers to form a product comprising fibers and nanoparticles. The nanoparticles can be separated or isolated in any suitable gaseous medium (e.g., air, helium, nitrogen, oxygen, carbon dioxide, etc.) and dispersed into a product, substrate, or fiber stream via an airflow, aerosol, evaporator, spray, or other suitable delivery mechanism.

[0027] Individual nanoparticles are separated and / or isolated in a gaseous medium, and then dispersed into a substrate, resulting in a more uniform distribution of nanoparticles throughout the product. Furthermore, the nanoparticles can be dispersed or distributed into the product “at a certain depth.” As used herein, the term “at a certain depth” means that the nanoparticles are dispersed across a first surface of the substrate, product, or other medium, such that at least some nanoparticles are arranged between the first and second opposing surfaces within the internal structure of the substrate.

[0028] In some implementations, the product is a filter medium and a filter, such as an air filter and a liquid filter. Nanoparticles increase the overall surface area of ​​the filter medium, which increases its filtration efficiency and allows for the capture of submicron contaminants without significantly impairing other factors, such as pressure drop across the filter (i.e., airflow). Furthermore, filters produced using the systems and methods described herein are capable of withstanding stringent conditioning, allowing the filters to maintain the same level of filtration performance throughout their entire lifespan.

[0029] In one specific aspect, the first apparatus includes a fibrosis device disposed between a feeding system and a suitable dispersing device. As used herein, the term "fibrosis" means the transformation (e.g., opening, separating, isolating, and / or individualizing) of clusters, clumps, or other groups of nanoparticles into individual nanoparticles with a size of less than 1 micrometer in at least one dimension.

[0030] In one embodiment, the second device includes a nozzle or similar device for dispersing individual nanoparticles onto a first surface of a fiber-containing substrate, such that the nanoparticles penetrate at least through the first surface of the substrate. The nozzle is preferably configured to disperse the nanoparticles into the substrate at a certain depth. In some embodiments, the nozzle disperses the nanoparticles across substantially the entire medium from the first surface to the opposing second surface. In other embodiments, the nozzle disperses the nanoparticles within a portion of the medium at a location between the first and second surfaces. In other embodiments, the nozzle disperses the nanoparticles along a density gradient from the first surface of the substrate to the opposing second surface. The density of the nanoparticles may be greater at either the first or second surface.

[0031] The second device may also include a negative pressure source or a vacuum source, which is positioned below the substrate and opposite the nozzle to increase the penetration depth and uniformity of the nanoparticles. The negative pressure source can be any suitable suction device that draws the nanoparticles through the substrate, such as a suction pump.

[0032] The second device may also include a feeder for advancing the substrate from the upstream end to the downstream end. A nozzle is preferably positioned between these two ends to disperse the nanoparticles onto the substrate. In some embodiments, the feeder may also include a support surface extending between the two winding machines to support the substrate as it moves downstream through the system. In other embodiments, the substrate is unwound directly from the unwinding machine to the winding machine without the need for another support surface.

[0033] The second device may also include a coating device for dispersing the adhesive onto the fibers in the substrate. The adhesive may comprise a variety of conventional materials, including natural materials (e.g., starch, dextrin, guar gum, etc.) or synthetic resins (e.g., EVA, PVA, PVOH, SBR, polyglycolic acid, etc.). In some embodiments, the substrate comprises its own adhesive composition. In these embodiments, the adhesive may or may not be added to the substrate. In one such embodiment, the substrate comprises bio-component fibers, one component of which includes an outer sheath at least partially surrounding an inner core.

[0034] The coating apparatus may include any suitable means for dispersing adhesive across a substrate. In one embodiment, the coating apparatus includes a spraying device having an upstream end adjacent to a feeder and an outlet of a nozzle. The sprayer may be located downstream of the fiberization apparatus so that the adhesive can be sprayed after the nanoparticles are deposited. In other embodiments, the system may include two sprayers: one located upstream of the fiberization apparatus and a second sprayer located downstream of the fiberization apparatus to coat the substrate with a second adhesive after the nanoparticles are deposited.

[0035] The second device may also include a negative pressure source or a vacuum source positioned below the substrate, opposite the sprayer, to increase the penetration depth and uniformity of the adhesive. The negative pressure source can be any suitable suction device that draws the adhesive through the substrate, such as a suction pump.

[0036] The second device may also include a dryer, such as an IR oven, which is located near the downstream end of the feeder for heating the nanoparticles and fibers to bond the nanoparticles to the fibers within the substrate.

[0037] The fiberization apparatus may include a gas source, such as compressed air or other suitable gas, and a pump for drawing smaller clusters of nanoparticles from the separator and into the apparatus through channels. The compressed air source provides the moving fluid, causing the nanoparticles to circulate throughout the fiberization apparatus and ultimately exit through nozzles. The pump may include any suitable pump, such as a positive displacement pump, a centrifugal pump, an axial flow pump, etc. In one embodiment, the pump includes an ejector configured to generate sufficient negative pressure to draw small clusters of nanoparticles from the separator and into the pump through channels.

[0038] The system may also include an energy source, such as a second pump, a second ejector, etc., coupled to the first ejector and configured to push clusters of small nanoparticles from the first ejector toward a surface at a sufficient velocity to break up the nanoparticles and convert at least some of the clusters of small nanoparticles into individual nanoparticles. The applicant has found that pushing nanoparticles toward a suitable surface at a velocity of about 500 feet per minute (fpm) to about 10,000 fpm, preferably about 2,000 fpm to about 6,000 fpm, is sufficient to break up at least some of these nanoparticles into individual nanoparticles.

[0039] The surface can be any surface that obstructs the flow of nanoparticles through the channel, such as the inner wall of the channel at the junction, or other inner walls that change direction, such as curved surfaces, vertical surfaces, etc. Alternatively, the channel can include a wall or other surface disposed within the channel or protruding into the channel in the fluid path. In one embodiment, the channel extends to a substantially T-shaped connector, which includes two separate channels extending from the connector. A second ejector is configured to push the nanoparticles against the wall of the T-shaped connector at a velocity sufficient to disperse at least some of the nanoparticles.

[0040] In some embodiments, the fiberization apparatus further includes one or more reactors for separating individual nanoparticles that have been isolated from nanoparticle clusters that have not yet been completely decomposed. The reactor includes a shell coupled to a channel and has an inner chamber and a negative pressure source configured to draw smaller clusters of nanoparticles away from the individual nanoparticles.

[0041] In each embodiment, the reactor includes a rod or tube extending through an inner chamber and one or more inlets located at one end of the inner chamber and substantially surrounding the tube; in some embodiments, the inlet may extend substantially through the center of the inner chamber. The inlets are coupled to one or more channels, such that clusters of nanoparticles and individual nanoparticles are drawn into the chamber through the one or more inlets. The central tube includes an opening at the end opposite to the one or more inlets. The opening is coupled to an internal channel within the tube and has an outlet coupled to a nozzle or other dispersion device. This allows nanoparticles to enter the reactor through the inlets, then into the tube, and finally into the dispersion device.

[0042] The inlets can be oriented at an angle relative to the central tube, allowing the nanoparticles to enter the inner chamber at a lateral angle relative to the reactor's outer surface. In a preferred embodiment, at least one or more inlets are oriented such that when the nanoparticles enter the reactor, they move in a direction substantially tangential to the central tube. Once the nanoparticles enter the annular chamber surrounding the tube, their velocity vectors (velocity and direction) generate eddies within the reactor, causing them to vortex around the central tube from one end to the other. Because individual nanoparticles are significantly lighter than tangled nanoparticles that remain aggregated, these individual nanoparticles are drawn into the inlets of the central tube. The eddies within the chamber can further break up (e.g., open, separate, and / or individualize) the nanoparticle clusters as they pass through the reactor.

[0043] The reactor may also include one or more outlets located at opposite ends of one or more inlets. Larger, heavier clusters of nanoparticles that have not yet been broken down are extracted through one or more outlets. Thus, isolated and individualized nanoparticles are drawn into nozzles, while the nanoparticle clusters are extracted through the outlets. These outlets may be coupled to a first or second pump, or to an additional pump within a fibrillation unit designed to further break down the nanoparticle clusters and recycle them back into the reactor.

[0044] The description of the desired objectives fulfilled by the various embodiments of this specification is not intended to imply or suggest that any one or all of these objectives are essential features, either alone or collectively, present in the most generalized embodiment of this specification or in any more specific embodiment.

[0045] Brief description of the attached figures Figure 1 A system for manufacturing filter media is illustrated schematically; Figure 2 A system for decomposing and / or isolating individual nanoparticles and dispersing nanoparticles onto a substrate is illustrated schematically. Figure 3 It shows Figure 2 The system's injectors; Figure 4 It shows Figure 2 The system's reactor; Figure 5 Another embodiment of a system for decomposing and / or isolating individual nanoparticles and dispersing nanoparticles onto a substrate is shown; Figure 6 A system for manufacturing dual-layer filter media is shown; Figure 7 This is a schematic diagram of a feeding system used to deliver nanoparticles to a filter media manufacturing system described above. Figure 8yes Figure 7 A more detailed view of the feeding system; Figure 9 It is used to receive clusters of nanoparticles and introduce nanoparticles into... Figure 7 and Figure 8 A partial cross-sectional schematic diagram of the bulk material hopper in the feeding system; Figure 10 yes Figure 9 Another schematic diagram of the bulk silo; Figure 11 The rotor inside the bulk silo is shown; Figure 12 This is an enlarged view of the lower opening of the bulk silo, showing a portion of the lift, which is configured to convey nanoparticles out of the bulk silo and lift them through the feeding system; Figure 13 A portion of the elevator is shown; Figure 14 Another part of the elevator is shown; Figure 15 It shows Figure 14 The shown is a cluster of nanoparticles within a portion of the elevator. Figure 16 A receiver dish for conveying nanoparticles from an elevator to a feed hopper is shown. Figure 17 This is a schematic diagram of the feed hopper; Figure 18 This is another schematic diagram of the feed hopper; Figure 19 The internal parts of the feed hopper are shown; Figure 20 This is an enlarged view of the interior of the feed hopper, showing the screw conveyor used to transport nanoparticles out of the feed hopper; Figure 21 Another receiver dish is shown for conveying nanoparticles from the feed hopper to the fiber manufacturing system; Figure 22 A fine-tuning flow control device for conveying nanoparticles into fiber manufacturing equipment is shown; Figure 23 A vibrating element is shown for vibrating a receiver dish to transport nanoparticles through it; Figure 24 It is a side view of a filter medium containing nanoparticles dispersed in a portion of the material. Figure 25 It is a side view of a filter medium containing nanoparticles dispersed throughout the material; Figure 26 It is a side view of a filter medium having nanoparticles dispersed in the material in a gradient. Figure 27 The dual-layer filter media is shown; Figure 28 A filter medium with a support layer is shown; Figure 29 This illustrates a filter medium having nanoparticles dispersed at a certain depth in a material and a loosely woven fabric layer covering the nanoparticles; and Figure 30 A bilayer filter medium with nanoparticles dispersed on the inner surfaces of two layers is shown. Detailed Implementation

[0046] This specification and accompanying drawings illustrate exemplary embodiments and should not be considered limiting. The scope of this specification is defined by the claims (including equivalents). Various mechanical, compositional, structural, and operational changes may be made without departing from the scope of this specification and the claims (including equivalents). In some cases, well-known structures and techniques have not been shown or described in detail to avoid obscuring the description. Identical numbers in two or more drawings represent the same or similar elements. Furthermore, whenever feasible, elements and related aspects described in detail with reference to one embodiment may be included in other embodiments where they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment but not with reference to a second embodiment, that element may still be included in the second embodiment. Moreover, the descriptions herein are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the system or illustrated components.

[0047] It should be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” and any singular use of any word, include plural referents unless clearly and explicitly defined as a single referent. As used herein, the term “comprising” and its grammatical variations are intended to be non-limiting, such that the description of items in the list does not exclude other similar items that may be substituted for or added to the listed items.

[0048] Unless otherwise stated, all quantitative values ​​are approximate, whether or not words such as "about" or "approximately" are used. The materials, methods, and embodiments described herein are exemplary only and are not intended to be limiting.

[0049] Systems, apparatus, and methods for manufacturing products including filter media and filters are provided. Filter media and filters manufactured using the processes and methods described herein are also provided. Filter media may include a substrate comprising at least one or more fiber layers, such as webs, sheets, membranes, open-cell membranes, meshes, reticles, or other media. The one or more fiber layers comprise one or more fibers and include nanoparticles incorporated into at least a portion of at least one fiber layer. Filters may include, but are not limited to, gas filters (e.g., HEPA and / or HVAC filters), liquid filters, gas turbine and compressor inlet filters, plate filters, filter presses, membrane bioreactor membranes, hydrocarbon filters, diesel filters, fuel filters, hydraulic fluid filters, food and beverage filters, semiconductor filters, microfiltration membranes, downstream membrane filtration, pharmaceutical and medical filters (e.g., CPAP filters, face masks, etc.), wastewater filters, industrial process and / or municipal filters, gas turbine and compressor inlet filters, plate filters, cartridge filters, bag filters, clean-in-place (CIP) filters, battery separators, etc.

[0050] While the following description pertains primarily to filter media and gas or liquid filters, it should be understood that the apparatus and methods disclosed herein can be readily adapted to a wide range of other applications. For example, the filter media disclosed herein can be used in household cleaning products, roofing and flooring products, automotive interiors and roof linings, reusable bags, wall coverings, filtration devices, insulation materials, and more. Furthermore, the individual nanoparticles isolated and generated in the methods described herein can be used in a variety of coatings, composites, and / or additives, such as polymers, food packaging, flame retardants, fuel cells, battery packs, capacitors, nanoceramics, lamps, materials manufacturing, production methods, reinforcements for composites, cement, and other materials, medical diagnostic applications, medical therapeutic devices or therapies, tissue engineering (e.g., scaffolds for bone or tissue repair), drinking water, industrial process fluids, food and beverage products, pharmaceuticals and biologics, tissue imaging, medical therapy delivery, environmental applications (e.g., biodegradable compounds), and more.

[0051] Preferably, the nanoparticles have at least one dimension smaller than 1 micrometer (i.e., diameter, width, height, etc., depending on the cross-sectional shape of the fiber). In some embodiments, the nanoparticles comprise microfibers or nanofibers having at least one dimension of about 5 micrometers or greater. For example, nanofibers with a diameter or width less than 1 micrometer and a length greater than 1 micrometer are nanoparticles as used herein. Nanoparticles can have a continuous length or can have discrete lengths, for example, from 1 to 100,000 micrometers, preferably from about 100 to 10,000 micrometers.

[0052] In some embodiments, each individual nanoparticle can be a small particle with a size of about 1 to about 1000 nanometers, preferably about 1 to about 650 nanometers. In the number-size distribution, at least half of the particles can be measured to be 100 nanometers or less. Most nanoparticles typically consist of only a few hundred atoms. When the size of nanoparticles approaches the atomic scale, the material properties change. This is due to the increased surface area to volume ratio, resulting in the surface atoms of the material dominating its properties. Because nanoparticles are so small, their surface area to volume ratio is very large compared to bulk materials such as powders, plates, sheets, or even larger fibers. This characteristic gives nanoparticles unexpected optical, physical, and chemical properties, as they are small enough to confine their electrons and produce quantum effects.

[0053] The substrate can include a structure of individual fibers or threads interwoven, interlocked, or bonded together. For example, nonwoven fabrics can include sheet or web structures bonded together by mechanically, thermally, or chemically entangled fibers or filaments (and by perforated membranes). They can be substantially flat, porous sheets made directly from individual fibers or molten plastic or plastic film. Examples of suitable nonwoven materials include, but are not limited to, fibers, layers, or webs treated by meltblowing, spunbonding or hydroentangling, thermal bonding, bonded carding, air-laid, wet-laid, co-forming, needle punching, stitching, hydroentanglement, thermal bonding, etc.

[0054] In some embodiments, the substrate may comprise knitted and / or woven materials. Knitted materials may include any knitted pattern suitable for the desired application. Suitable knitted materials for filter applications include weft knitting, warp knitting, knitted mesh, compressed knitted mesh, etc. Suitable woven materials for filter applications include textile filter media, such as monofilament fabrics, multifilament fabrics, nylon mesh, polyester mesh, polypropylene mesh, etc. Woven textiles can be used, for example, for mesh filter press filter cloths, woven filter pads and other die-cut parts, centrifuge filter bags, liquid filter bags, dust collector filter bags, bed dryer filter bags, rotary drum filters, filter belts, leaf filters, rolled media, etc.

[0055] In some embodiments, the filter medium may include a structure comprising mixed or entangled chopped fibers and / or filaments. As used herein, chopped fibers refer to fibers of finite length. Filaments, as used herein, refer to fibers having a substantially continuous length. In some embodiments, the substrate may include chopped coarse fibers, microfibers, and / or fine fibers. As used herein, "fine fiber" refers to a fiber having a diameter of less than 1 micrometer, "coarse fiber" refers to a fiber having a diameter of greater than 10 micrometers, and "microfiber" refers to a synthetic fiber having a diameter of less than 10 micrometers.

[0056] In some embodiments, the nanoparticles are dispersed within the substrate “at a certain depth.” As used herein, the term “at a certain depth” means that the nanoparticles are dispersed across a first surface of the fiber layer, such that at least some of the nanoparticles are arranged between the first and second opposing surfaces within the internal structure of the filter medium. In some embodiments, the nanoparticles are dispersed across substantially the entire medium from the first surface to the opposing second surface. In other embodiments, the nanoparticles are dispersed within a portion of the medium at a location between the first and second surfaces.

[0057] In some implementations, the nanoparticles are spatially distributed in three dimensions relative to the supporting fibers, which can increase the fiber surface area and microvolume within the filter medium.

[0058] The three-dimensional distribution can also prevent complete clogging of specific sections of the filter media, which is particularly useful in filter media because it allows fluids (such as air and other gases) to pass through the filter, thereby reducing the overall pressure drop across the filter.

[0059] In other embodiments, the nanoparticles are arranged across the thickness of the fiber layer in a density gradient, such that the density of nanoparticles disposed near a surface is higher than that of the opposite surface, or the density of nanoparticles disposed on the surface is higher compared to the middle portion of the fiber layer. The density gradient can be substantially linear, it can decrease in the form of a series of discrete steps, or the gradient can be random (i.e., the decrease in density is typically not linear or stepwise). Such a density gradient provides many advantageous characteristics for certain applications (e.g., filters) (discussed below).

[0060] Nanoparticles can include any suitable material, such as glass, biosoluble glass, ceramic materials, acrylics, carbon, metals (e.g., alumina), polymers (e.g., polyethylene, high-density polyethylene (HDPE), low-density polyethylene (LDPE), nylon, polyethylene terephthalate, polypropylene (PP), polybutene (PBT), ethylene polyester (PET), polylactic acid (PLA), polyamide (PA), polyvinyl chloride (PVC), polyolefins, polyacetals, polyesters, cellulose ethers, polyalkylene sulfides, poly(aryloxides), polysulfones, modified polysulfone polymers, and polyvinyl alcohol, polyamides, polystyrene, polyacrylonitrile, polyvinylidene chloride, polymethyl methacrylate, polyvinylidene fluoride, and any combination thereof).

[0061] In some embodiments, the nanoparticles can be fabricated into bicomponent segmented disc-shaped and island-shaped forms. The filaments are then stretched to obtain submicron filaments. The continuous filament nanoparticles are cut to the desired length (preferably about 100 to about 10,000 micrometers).

[0062] In some embodiments, the nanoparticles are absorbents and adsorbents. In some embodiments, the nanoparticles are activated carbon fibers or activated carbon powder. In some embodiments, the nanoparticles are catalytic particles or catalytic fibers. In some embodiments, nanoparticles can be obtained by feeding submicron fibers into a pulverizer, crusher, or trimmer, wherein bonded fibers enter and are chopped into short fibers. For example, submicron nanoparticles can be obtained by feeding low-weight bio-component meltblown or nano-meltblown fabric into a pulverizer.

[0063] In some implementations, different nanoparticles can be mixed. For example, nanoparticles and nanobeads can be mixed. Two different nanoparticles with different melting points can also be mixed, allowing the lower-melting-point nanoparticles to act as a binder for the higher-melting-point nanoparticles. Nanoparticles with different diameters and lengths can also be mixed.

[0064] In some embodiments, the nanoparticles are selected from environmentally sustainable raw materials. Nanoparticles may include biosoluble glass nanoparticles, biodegradable nanoparticles, compostable nanoparticles, or recyclable compositions.

[0065] Different types of nanoparticles can be combined. Some nanoparticles can be functional nanoparticles. For example, functional nanoparticles may include activated carbon and / or antimicrobial materials deposited on and / or attached to fibers in the filter medium. This can improve the gas absorption efficiency and bactericidal efficacy of the fibers. In addition, fiber products with microfibers deposited with glass and carbon nanoparticles can provide filtration and deodorization functions as filter media.

[0066] In some embodiments, nanoparticles are bonded to fibers via mechanical entanglement. This mechanical bonding may be aided by adhesives or binders, as discussed in more detail below. In some embodiments, the nanoparticles are not curled (i.e., they do not include the pronounced wavy, curved, coiled, serrated, or similar shapes associated with nanoparticles in a relaxed state). In other embodiments, the nanoparticles may have a curled structure of discrete lengths. For example, when these curled nanoparticles with discrete lengths are attached to fibers, they become entangled with each other and are also firmly attached to, adhered to, and attached around the fibers, thereby forming modified fibers. In other embodiments, the attachment of nanoparticles to microfibers is achieved via electrostatic attraction and / or van der Waals attraction between the fibers and nanoparticles.

[0067] Filters, such as gas and / or liquid filters, are also provided that include nanoparticles dispersed at a certain depth within the filter. In some embodiments, the filter includes one or more support layers bonded to the filter medium. The support layer and / or filter medium may include nanoparticles dispersed at a certain depth within the layer. In some embodiments, a polymer layer, film, or membrane is provided that includes one or more pores for gas or liquid to flow through, wherein the nanoparticles are arranged at a certain depth within the polymer layer. In other embodiments, the filter medium includes a flexible surface layer for finger bandage pads, face masks, etc.

[0068] This document provides systems, apparatus, and methods for producing filter media and products containing filter media (e.g., gas or liquid filters). Systems and methods are also provided for isolating individual nanoparticles in a gaseous medium, such as air, helium, nitrogen, oxygen, carbon dioxide, etc. (rather than a liquid), and for dispersing the nanoparticles into another product, membrane, layer, or substrate via an airflow, aerosol, evaporator, spray, or other suitable delivery mechanism.

[0069] Figure 1 A schematic diagram illustrates an entire system 110 for manufacturing the filter media and other products described herein. As shown, system 110 includes a feeder 120 for advancing layers 130 of fibers or other materials during the manufacturing process. System 110 also includes a coater 140, a nanoparticle dispersion system 150, and a heating and / or drying device 160. In some embodiments, system 110 further includes a vacuum or other negative pressure source 170 located below the substrate 130, opposite the fiberization system 150.

[0070] In one embodiment, the feeder 120 includes a winder 122 located downstream of the process and an unwinder 124 located upstream, which continuously winds the fiber layer 130 through the system 100. In some embodiments, the feeder 120 may also include a support surface (not shown) extending between the winders for supporting the fiber layer 130 as it moves downstream through the system 100. In other embodiments, the fiber layer is unwound directly from the unwinder 124 to the winder 122 without the need for another support surface.

[0071] The coating machine 140 is configured to spray droplets of adhesive or bonding material (e.g., glue or adhesive) onto the fiber layer 130, allowing nanoparticles to adhere to the fibers within the layer 130 to form a stable matrix. The adhesive is preferably present in a relatively small amount to bond individual nanoparticles to the fibers throughout the layer 130. In a preferred embodiment, the coating machine 140 includes a nozzle sized to generate adhesive droplets with a diameter of approximately 20 to 30 micrometers to increase the penetration depth of the adhesive through the layer 130. Of course, droplet size can be affected by many other parameters, including air pressure, air volume, air temperature, humidity, spray nozzle design, the rheology / viscosity of the adhesive, carrier, etc.

[0072] Of course, it should be recognized that coating a substrate with an adhesive or bonding material can be achieved by other coating methods, including ultrasonic spraying, dip coating, spin coating, gravure coating, licker roller coating, screen coating, powder coating, electrostatic coating, sputtering coating, or similar coating techniques.

[0073] Adhesives can comprise a variety of conventional materials, including natural materials (such as starch, dextrin, guar gum, etc.) or synthetic resins (such as EVA, PVA, PVOH, SBR, etc.). In some embodiments, solvent-based adhesives are used, wherein bonding occurs upon solvent evaporation.

[0074] In one preferred embodiment, the binder comprises dextrin. In another embodiment, the binder comprises a composition of various substances, such as water, 2-hexyloxyethanol, isopropanolamine, sodium dodecylbenzenesulfonate, laurylamine oxide, and ammonium hydroxide. In yet another embodiment, the binder comprises PVOH. The binder can be a solution, emulsion, suspension, hot melt, curable material, pure substance, and / or a combination thereof.

[0075] In some embodiments, an adhesive resin is used, and the adhesive resin can be cross-linked after the adhesive is applied to the fiber layer 130. Adhesion (water resistance / solvent resistance) can be promoted by self-cross-linking during solvent evaporation in the adhesive formulation or by thermal activation during the drying process. For some adhesives, cross-linking can be achieved by electromagnetic radiation of high-energy wavelengths (including but not limited to RF, UV, or electron beams). The amount of adhesive can be controlled by adjusting the nozzle size of the sprayer 140 or by controlling the flow rate of the adhesive composition.

[0076] In some embodiments, the adhesive may contain surfactants to reduce the surface or interfacial tension of the adhesive, thereby improving its dispersibility and wetting properties, and making it easier for the adhesive to penetrate to a certain depth into the substrate. Suitable surfactants for use with the adhesives disclosed herein include nonionic, anionic, cationic, and amphoteric surfactants, such as sodium stearate, 4-(5-dodecyl)benzenesulfonate, sodium dodecylbenzenesulfonate wetting agents, docusate (sodium dioctyl sulfonate), alkyl ether phosphates, benzalkonium chloride (BAC), perfluorooctane sulfonate (PFOS), etc.

[0077] In some embodiments, the sprayer 140 is located upstream of the nanoparticle dispersion system 150 to spray the adhesive before the nanoparticles are deposited. In other embodiments, the sprayer 140 is located downstream of the system 150 so that the adhesive can be sprayed after the nanoparticles are deposited. In other embodiments, the system 100 includes two sprayers; one is located upstream of the system 150, and a second sprayer (not shown) is located downstream of the system 150 to coat the fiber layer 130 with a second adhesive after the nanoparticles are deposited.

[0078] In some implementations, each sprayer 140 has more than one nozzle head. For example, the nozzle heads may be arranged in series to achieve better uniformity or increase the fiber spraying width. Alternatively, the nozzle heads may be placed parallel (i.e., across the width of the substrate) to ensure that the adhesive is applied across the entire width of the substrate.

[0079] In a preferred embodiment, a negative pressure source or vacuum source (not shown) is arranged below the fiber layer 130, opposite the sprayer 140, to increase the penetration depth and uniformity of the adhesive. The negative pressure source can be any suitable suction device that draws the adhesive through the substrate, such as a suction pump.

[0080] In some embodiments, the fiber layer comprises its own adhesive composition. In these embodiments, an adhesive may or may not be added to the fiber layer. In one such embodiment, the fiber layer comprises biological component fibers, one component comprising an outer sheath at least partially surrounding an inner core. In some embodiments, the sheath and core may be substantially concentric with each other. In other embodiments, the core may be non-concentric with the sheath. In other embodiments, the core and sheath may be arranged side-by-side with each other. Of course, other configurations are also possible. For example, the core may comprise shapes other than circular, such as dog-bone shaped, square, triangular, rhomboid, etc. Alternatively, the fiber may comprise multiple cores, or may be divided into three, four, or more quadrants.

[0081] The sheath may contain a material that binds to the nanoparticles. For example, the sheath may contain a material that becomes viscous and / or fluid upon heating and / or drying. During the heating / drying step, the sheath portion of the fiber is heated to its melting point until it becomes viscous and / or fluid to bind the nanoparticles to the fiber layer. In a preferred embodiment, bonding and drying are performed simultaneously within the drying apparatus 160.

[0082] Figure 2 A nanoparticle dispersion system 150 (or fibrillation system) for converting groups of nanoparticles into individual nanoparticles is schematically illustrated. As used herein, the term "fibrillation" refers to the conversion (e.g., opening, separating, isolating, and / or individualizing) of clusters, clumps, or other groups of nanoparticles that may or may not be entangled into each other into individual nanoparticles with a size of less than 1 micrometer in at least one dimension. The dispersion system 150 converts large entangled clusters of nanoparticles into smaller entangled clusters of nanoparticles, and then into individual nanoparticles.

[0083] As shown in the figure, system 150 includes a feeder 200, such as a hopper, for introducing larger or larger clusters / agglomerates of nanoparticles into system 150. The feeder 200 may include any suitable hopper device known to those skilled in the art and is preferably configured to introduce large particle clusters into the process at a specified rate, which will depend on the downstream fibrosis rate. Nanoparticles may be introduced continuously at the specified rate or at intervals at a specific rate. Large clusters of nanoparticles may be broken up before being introduced into the feeder 200.

[0084] It should be recognized that nanoparticles can be introduced into system 150 in a variety of different forms. For example, the original nanoparticles can be fabricated into long, separated fibers. In this form, the nanoparticles can be cut to obtain the desired aspect ratio.

[0085] System 150 also includes a separator 210, such as a mixer, for separating or breaking down large nanoparticle clusters / agglomerates into smaller clusters / agglomerates. Feeder 200 conveys nanoparticles into separator 210 in a stable and continuous manner by any mechanical means. The conveying speed will depend on various factors, such as the speed at which the substrate 130 travels along feeder 120 and the fibrosis rate of the nanoparticles. By controlling the amount of nanoparticles falling into separator 210, the amount of nanoparticles dispersed in the substrate can be controlled, thereby enabling a continuous manufacturing process.

[0086] In one embodiment, the separator 210 includes a housing 212 having a first opening 214 coupled to a feeder 200 and a second opening 216 coupled to a downstream process. The second opening 216 is preferably sized to allow only clusters of nanoparticles of a certain size to pass through. The separator 210 may include a plurality of rotatable blades (not shown) designed to rotate about a vertical axis within the housing 212 to separate and open coarse nanoparticle clusters. The blades may have the same or different pitch and camber to allow entangled fibers to sequentially break down or “open” as they are conveyed from the first opening 214 to the second opening 216. The following... Figures 7-13 An embodiment of a feeder 200 and a separator 210 for a continuous manufacturing process is described.

[0087] System 150 also includes an airflow extending throughout the system from separator 210 to nozzle 220 (discussed in more detail below). The airflow (along with a series of pumps discussed below) provides the power to move the nanoparticles through system 150. In one embodiment, the airflow is generated by an air compressor 230 configured to supply compressed air to the system, but it should be recognized that other forms of gas can be used to convey the nanoparticles through system 150.

[0088] System 150 includes one or more pumps for moving nanoparticle clusters throughout the system and ultimately moving individual nanoparticles. The pumps can include any suitable pump, such as a positive displacement pump, centrifugal pump, axial flow pump, etc. In one embodiment, a first pump 240 includes a first inlet fluidly coupled to an air compressor 230 via a first channel 242 and a second inlet fluidly coupled to a separator 210 via a second channel 244. Compressed air is drawn into the first pump 240, which creates a negative pressure (e.g., a vacuum) to draw nanoparticle clusters from the separator 210 into the pump (discussed in more detail below). System 150 may also include a second pump 250 and a third pump 260, each fluidly coupled to the outlet of the first pump 240. Similarly, the second pump 250 and the third pump 260 create a negative pressure to draw nanoparticle clusters through a third channel 252.

[0089] In some embodiments, pump 240 includes injector 300. For example... Figure 3As shown, each ejector 300 includes a motive fluid inlet 302 and a nanofiber inlet 304, which are coupled to an outlet 306 via a fluid channel 308. The fluid channel 308 includes a converging inlet nozzle 310, a diffuser throat 312, and a diverging outlet diffuser 314. High-pressure, low-velocity air is converted into low-pressure, high-velocity air, thereby generating the pressure difference required for suction. Based on the Venturi effect and Bernoulli's principle, a primary fluid medium (e.g., compressed air) is used to create a vacuum to draw nanoparticles into the ejector 300 and discharge them through the outlet 306. The diameter of the ejector 300 depends on the volumetric velocity of the compressed air, the suction requirement, the pressure drop, and the fluid pressure of the compressed air.

[0090] review Figure 2 The third channel 252 includes a connector 254 that divides the third channel 252 into two independent channels, each leading to the second pump 250 and the third pump 260. The connector 254 preferably includes a surface or wall arranged substantially perpendicular to the third channel 252, thus forming a T-shaped intersection. This surface can be any surface that obstructs the flow of nanoparticles through the channel, such as the inner wall of the channel at the junction, or other inner walls that change direction, such as curved surfaces, vertical surfaces, etc. Alternatively, the channel can include a wall or other surface arranged within the channel or protruding into the channel in the fluid path. In one embodiment, the channel extends to a substantially T-shaped connector comprising two independent channels extending from the connector. The second injector is configured to draw nanoparticles into the T-shaped connector at a speed sufficient to disperse at least some of the nanoparticles.

[0091] As the nanoparticle clusters move through the third channel 252, they are pushed against the surface or wall by the negative pressure applied by the second pump 250 and the third pump 260. The velocity of the nanoparticles relative to the connector 254 generates collisions with sufficient kinetic energy, causing at least some nanoparticle clusters to break into smaller nanoparticle clusters and / or individual nanoparticles with at least one dimension smaller than 1 micrometer.

[0092] To generate the kinetic energy required to break up the nanoparticle clusters, air is propelled throughout the system 150 at a speed of approximately 500 feet per minute (fpm) to approximately 10,000 feet per minute, preferably approximately 2,000 fpm to approximately 6,000 fpm. System 150 includes a sufficient amount of suction pressure, preferably at least approximately 20 psi. This suction pressure generates a total pressure of at least approximately 100 psi throughout the system.

[0093] In some embodiments, system 150 further includes a fourth fluid passage 262 and a fifth fluid passage 264 that couple the outlets of the second pump 250 and the third pump 260 to reactor 270. For example... Figure 4As shown, reactor 270 includes a top surface 272, a bottom surface 274, and an internal annular chamber 276 extending from the top surface 272 to the bottom surface 274. Reactor 270 also includes a central tube 275 having an open upper inlet 278 and an outlet 280. Reactor 270 may also include one or more upper outlets 282. Reactor 270 may be coupled to an energy source (not shown) configured to generate a vortex of swirling gas within the annular chamber 276. The energy source may include any suitable energy source, such as a pump, compressor, generator, etc. The swirling gas preferably flows from the bottom to the top of reactor 270 around the central tube 275 to cause nanoparticle clusters and individual nanoparticles to move upwards from the bottom surface 275 to the top surface 272.

[0094] In another embodiment, the generation of vortices does not require a separate energy source. In this embodiment, nanoparticle clusters 290 and individual nanoparticles 292 enter reactor 270 through bottom inlets 284, 285, 286, and 287. Inlets 284, 285, 286, and 287 are inclined upwards to facilitate the movement of nanoparticles around a central tube 275. In a preferred embodiment, at least one or more of inlets 284, 285, 286, and 287 are inclined such that the nanoparticles are substantially tangential to the central tube 275 when entering reactor 270. Once the nanoparticles enter annular chamber 276, their velocity vectors (velocity and direction) generate vortices within reactor 270, causing them to swirl around the central tube 275 and rise to the upper part of chamber 276. The swirling gas preferably flows from the bottom to the top of reactor 270 around the central tube 275 to move nanoparticle clusters and individual nanoparticles from the bottom surface 275 to the top surface 272. Nanoparticles 290 and 292 are blown from the bottom to the top of the reactor undisturbed. The eddies within chamber 276 can further decompose (e.g., open, separate, and / or individualize) the nanoparticle clusters 290 as they pass through reactor 270.

[0095] In some embodiments, reactor 270 may also be coupled to an energy source (not shown) configured to generate vortices of swirling gas within annular chamber 276. The energy source may include any suitable energy source, such as a pump, compressor, generator, etc.

[0096] System 100 may also include another pump or negative pressure source coupled to the upper outlet 282. This negative pressure draws the fibers out of outlet 282, causing the fibers 290 to exit reactor 270. Since individual nanoparticles 292 are significantly lighter than tangled nanoparticles 290 that are still aggregated, these individual nanoparticles 292 are drawn into the upper inlet 278 of the central tube 275. Simultaneously, larger and heavier clusters of nanoparticles 290 that have not yet been decomposed are drawn out from upper outlet 284. Upper outlet 284 may be coupled to another pump (not shown) or to the first pump 240. In this way, the nanoparticle clusters 290 are reintroduced into the process for further decomposition, thus forming a refeed system for further decomposition of the remaining nanoparticle clusters.

[0097] The outlet 280 of the central tube 275 is coupled to the nozzle 220 (see...) Figure 2 Individual nanoparticles 292 are drawn into nozzle 220, where they are dispersed onto a substrate surface or into a fiber stream (discussed below). Nozzle 220 may comprise any suitable nozzle known to those skilled in the art. In one embodiment, nozzle 220 has multiple outlets whose external dimensions are customized according to the dimensions (i.e., area) of the substrate beneath nozzle 220. Nozzle 220 disperses the nanoparticles onto the substrate at a rate driven by the pressure of the entire system.

[0098] In some embodiments, system 100 includes more than one nozzle coupled to outlet 280 of reactor 270. The nozzles may be arranged on the substrate in any suitable manner (e.g., side-by-side, in series, in parallel, etc.).

[0099] It should be recognized that pump 240 or pumps 250, 260 can directly feed the nanofiber / air mixture into nozzle 220 (i.e., bypassing reactor 270). In this embodiment, the pressure within the system is designed to generate sufficient kinetic energy to break down or break up substantially all of the nanoparticles into individual nanoparticles, thus eliminating the need for reactor 270 to separate nanoparticles from larger fiber clusters.

[0100] For reference Figure 5 Another embodiment of the nanoparticle dispersion system 320 will now be described. As shown, system 320 includes a separator 325 for separating larger or larger clusters of nanoparticles into smaller clusters that will pass through system 320. A first ejector 326 is coupled to the outlet of separator 325 for drawing nanoparticles from separator 325 into system 320. An air compressor (not shown) is also coupled to ejector 326 to provide motive fluid, as discussed above.

[0101] Similar to the previous implementation, the second ejector 330 and the third ejector 340 are coupled to the outlet of the first ejector 326. Nanoparticles are extracted from the first ejector 320 and pushed toward the surface of the T-shaped intersection 350 to break at least some of the nanoparticles into smaller clusters or individual nanoparticles.

[0102] Each of the second ejector 330 and the third ejector 340 has an outlet coupled to additional T-shaped intersections 360 and 370. As before, the nanoparticles are pushed toward the surface of the T-shaped intersections 360 and 370 for further decomposition. The T-shaped intersections 360 and 370 are each coupled to two fluid channels leading into the bottom 380 of the reactor. Therefore, the bottom 380 of the reactor has four separate inlets 382, ​​384, 386, and 388 for the passage of the nanoparticles. Each of these inlets is preferably inclined upwards and located at an opposite corner of the reactor. This allows the nanoparticles to enter the vortex of the reactor and then vortex upwards to the upper part 390 of the reactor.

[0103] As previously referenced Figure 4 The reactor discussed comprises an annular chamber with a central tube having an open upper end and a lower end coupled to a nozzle. Nanoparticles, sufficiently decomposed into individual nanoparticles, flow through the open upper end and into the central tube for dispersion through the nozzle. Heavier clusters of nanoparticles that have not yet decomposed exit the reactor through one of four independent outlets 392, 394, 396, and 398. Ejectors 410 and 420 provide the power for extracting nanoparticles from the reactor 400, as discussed above. Outlets 392 and 394 are each coupled to ejector 410 via a T-junction 412, and outlets 396 and 398 are each coupled to ejector 420 via a T-junction 422. In this configuration, nanoparticles flow from two channels into one channel as they pass through junctions 412 and 422.

[0104] Injectors 410 and 420 are each coupled to T-junctions 430 and 440, respectively. As previously discussed, nanoparticles are pushed into T-junctions 430 and 440 for further breakdown into individual nanoparticles. T-junctions 430 and 440 are then coupled to the bottom 380 of reactor 400 (via inlets 432, 434, 442, and 444). This allows the nanoparticles to return to reactor 400 for further processing. This process is repeated continuously for each nanoparticle cluster until it is completely broken down into nanoparticles and enters the nozzle through a central tube. As a final step, the individualized nanoparticles are sprayed from the nozzle onto any substrate or mixed with any fiber spinning stream. During this process, suction power reaches up to 20 psi and pressure reaches up to 100 psi.

[0105] In some embodiments, system 150 or 200 may include a separate control system that monitors the nanoparticles to determine when they break down into individual nanoparticles suitable for passage through the nozzle. The control system may, for example, simply monitor the pressure throughout the system to ensure sufficient pressure is applied to the nanoparticles to break them down. Alternatively, the control system may include various sensors arranged within the system to detect characteristics of the nanoparticles, such as weight or size. The sensors may be arranged, for example, within reactor 400, such that the control system can control various parameters of reactor 400, such as negative pressure applied to outlets 392, 394, 396, 398, the velocity of the vortex passing around the annular chamber, or the pressure applied to the central tube to draw the nanoparticles into the nozzle.

[0106] Figure 6 Another embodiment of a system 500 for manufacturing multilayer filter media is shown. As shown, system 500 includes a first unwinder 502 and a second unwinder 504, and a single winding machine 506 for winding a first substrate 510 and a second substrate 512 downstream of system 500. As in previous embodiments, system 500 may also include a support surface (not shown) for each substrate 510, 512. The first unwinder 502 and the second unwinder 504 are used to advance the first substrate 510 and the second substrate 512 into the process, where they are joined together and then wound onto the single winding machine 506, as described below.

[0107] System 500 includes a first spray gun 520 and a second spray gun 522, each located downstream of a first unwinder 502 and a second unwinder 504, for applying adhesive to a first substrate 510 and a second substrate 512. System 500 also includes a first fiberization system / device 530 and a second fiberization system / device 532, located downstream of each spray gun 520, 522. As previously discussed, the fiberization devices 530, 532 generate individual nanoparticles and disperse these nanoparticles onto the substrates 510, 512.

[0108] After the nanoparticles are dispersed into substrates 510 and 512, the two substrates are joined together at connection point 540 so that they can be advanced downstream together. The two substrates can be bonded to each other at this point, or they can simply be placed one on top of the other.

[0109] System 500 also includes a heater / drying device, such as an IR oven 550, located downstream of the junction 540 of the two substrates. The heating / drying device heats and dries the two substrates to bond them together and to bond the nanoparticles to the fibers within the substrates. The substrates may, for example, be laminated together.

[0110] In some embodiments, nanoparticles are dispersed in two substrates 510, 512. In one such embodiment, system 500 is designed such that the nanoparticles are dispersed through a first surface of each substrate. The substrates can then be joined together such that the first surfaces face each other. Alternatively, the first surfaces can face away from each other (i.e., the substrates are joined at a second opposing surface of each substrate). In yet another embodiment, the first surface of the first substrate is connected to the second surface of the second substrate.

[0111] Figures 7-22 An embodiment of a feed system 600 is shown for separating or breaking down larger clusters / agglomerates of nanoparticles into smaller clusters and / or individual nanoparticles, and then conveying these smaller clusters and / or individual nanoparticles to one of the aforementioned filter manufacturing systems. The feed system 600 is particularly suitable for introducing nanoparticles into a continuous manufacturing process at a controlled mass or volumetric flow rate (i.e., the amount, volume, or total mass of nanoparticles passing through the feed system 600 per unit time). Nanoparticles can be introduced continuously at a specified flow rate or intermittently at specific flow rates. The conveying speed will depend on various factors, such as the substrate 130 along the feeder 120 (see...). Figure 1 Factors such as the travel speed, the fibrosis rate of the nanoparticles, and the desired amount of nanoparticles dispersed in a substrate of a given area / volume can be considered. By controlling the quantity, mass, or volume of nanoparticles falling into the manufacturing system, the amount of nanoparticles dispersed in the substrate can be controlled, resulting in a continuous manufacturing process with improved quality and yield, as well as reduced cost and time. Furthermore, the system is scalable and produces filter media with minimal variation.

[0112] like Figure 7 and Figure 8 As shown, the feeding system 600 typically includes a container or bulk bin 602, such as a hopper, for receiving relatively large (i.e., large) clusters or bundles of nanoparticles, and a lifter 604 for elevating the nanoparticles to a dispersion system 606, which disperses the nanoparticles into the filter manufacturing system (as described above). Large clusters or bundles of nanoparticles may be partially broken up before being introduced into the bulk bin 602, and / or they may be partially or completely broken up and separated within the container 602. It should be appreciated that nanoparticles can be introduced into the feeding system 600 in a variety of different forms. For example, the raw nanoparticles can be fabricated as long, separated fibers, such as nanofibers, microfibers, etc. In this form, the nanoparticles can be cut to obtain a desired aspect ratio.

[0113] The bulk hopper 602 can be used as a separator, such as a mixer, to separate or break down large clusters / bundles of nanoparticles into smaller clusters / aggregates, or directly separate or break down into individual nanoparticles. In one embodiment, the bulk hopper 602 includes a plurality of rotatable screws or rotors 610 designed to rotate about an axis within the bulk hopper 602 to separate and open coarse nanoparticle clusters (see discussion in more detail below). Figures 9-12 ).

[0114] like Figure 9 and Figure 12 As shown, rotor 610 can also be used to drive individual nanoparticles downward toward opening 612 at or near the bottom of container 602. Individual nanoparticles behave differently from macroscopic objects. Because the mass of nanoscale objects is so small, the attractive force of gravity between objects of this size is very small. Therefore, gravity has little or no effect on these particles (i.e., gravity does not automatically pull them downward toward opening 612). Opening 612 is coupled to collector 620 (see...). Figure 7 This is used to collect the individual nanoparticles that have been broken in container 602 and send them to elevator 604 (discussed in more detail below).

[0115] like Figure 9 As shown, rotor 610 can be driven by an external motor 612. In one embodiment, motor 612 includes a rotatable drive shaft 614 coupled to a cable or pulley system 616. Each rotor 610 may be formed on a rotatable disk or shaft 618 coupled to the pulley system 616, such that rotation of the drive shaft 614 causes rotation of the rotor 610. In some embodiments, a single motor 612 will drive all rotors 610. In other embodiments, the system may include multiple motors, each independently driving one or more rotors 610. Motor 612 may include any suitable motor, such as a brushless DC motor, permanent magnet DC motor, stepper motor, linear motor, synchronous motor, electromagnetic induction motor, servo motor, PMDC brushed motor, shunt motor, series motor, compound motor, etc.

[0116] like Figure 10 As shown, each rotor 610 includes a plurality of individual blades 622 circumferentially spaced around a central hub 624. In one such embodiment, each hub 624 includes five individual blades 622 evenly spaced around the hub; however, it should be appreciated that the blades may include fewer or more than five individual blades. The blades 622 may have the same or different pitch and camber to allow entangled fibers to sequentially untangle or “open” as they pass through the bulk bin 602.

[0117] In an exemplary embodiment, each central hub 624 is positioned such that its blades 622 rotate about an axis tangential to a vertical axis extending through the bulk hopper 602. In the exemplary embodiment, this axis is substantially perpendicular to the vertical axis of the bulk hopper 602. Therefore, as nanoparticle clusters pass downward through the bulk hopper 602, the blades 622 engage these clusters to separate or break them down into smaller nanoparticle clusters / clumps or directly into individual nanoparticles. The blades 622 also serve to force or convey nanoparticles downward through the bulk hopper 602. The bulk hopper 602 may include a single row of rotors 610 or multiple rows of rotors 610.

[0118] Rotors 610 can be configured to rotate in opposite directions, with some hubs 624 rotating counterclockwise and others clockwise. Alternatively, all rotors 610 can rotate in the same direction, i.e., either counterclockwise or clockwise. In an exemplary embodiment, container 602 includes a row of at least four rotors 610 extending substantially parallel to each other across a horizontal axis of container 602, each alternating propeller rotating in the opposite direction to its adjacent propeller, such as... Figure 10 As shown.

[0119] like Figure 8 and Figure 11 As shown, each central hub 624 of the rotor 610 preferably extends from one side 626 to the other side 628 of the bulk hopper 602 and includes multiple sets of blades 622 extending along its entire length. Each hub 624 may include two or more sets, five or more sets, ten or more sets, twenty or more sets, or forty or more sets of blades extending along its length, depending on the overall dimensions of the bulk hopper 602. Each set of blades is preferably spaced appropriately between each other to ensure that larger nanoparticle agglomerates do not fall between the sets of blades without contacting the blades.

[0120] In some embodiments, hubs 624 are staggered (vertically and / or horizontally) along the width and / or depth of bulk hopper 602 (see [reference]). Figure 11 This allows each set of blades 622 to cover different cross-sectional areas inside the bulk hopper 602. Furthermore, the blades 622 can be designed to overlap each other, such that one set of blades on one hub extends through the gap between two sets of blades on another hub 624. This ensures that the nanoparticle clusters located between the two sets of blades contact the blades of different hubs.

[0121] In one embodiment, container 602 includes a lower rotor 630, primarily used to sweep nanoparticles off the inner wall of bulk hopper 602 to drive them into opening 612 (see [link]). Figure 9 and 10For this purpose, rotor 630 preferably includes at least two rotating blades 632 surrounding a central hub 634. Hubs 634 preferably rotate in opposite directions, one hub rotating clockwise and the other counterclockwise, such that rotor 630 can sweep nanoparticles adhering to either side of container 602. Hub 634 preferably extends along an axis substantially perpendicular to the vertical axis of container 602, but it should be recognized that other embodiments are also contemplated. For example, bulk hopper 602 may include a plurality of rotors 630 positioned along the inner wall of bulk hopper 602 to sweep nanoparticles off these walls and drive them toward opening 612.

[0122] like Figure 7 As shown, the collecting vessel 620 has an upper opening coupled to the bulk hopper 602 and a lower opening connected to the lifter 604. The lower opening has a much smaller cross-sectional area than the upper opening, allowing the nanoparticles to "leak" downwards to control the flow rate of the nanoparticles through the system, as discussed in more detail below. Furthermore, the vessel 620 includes one or more mechanisms for conveying or driving the nanoparticles through it. In one embodiment, at least one of these mechanisms includes one or more vibrating elements 638 coupled to the vessel 620 (see [link to documentation]). Figure 23 The vibrating element 638 is used to convey nanoparticles through the vessel 620 and into the lifter 604. The vibrating element is also used to pulse the nanoparticles to break up those that tend to clump together within the vessel 620. This allows the nanoparticles to detach from these clumps and fall into the lifter 604.

[0123] The vibrating element may have an amplitude of about 5 to about 500 pounds of force, preferably about 75 to about 250 pounds of force, and may oscillate at a frequency of about 2,000 Hz to about 15,000 Hz, preferably about 7,000 Hz to about 11,000 Hz. The vibrating element may be located on the wall and / or inside the vessel 620. The vibrating element may be powered by any suitable means. In one embodiment, the vibrating element includes an electromechanical device powered by a DC power supply. The vibrating element converts current into pulses. In another embodiment, the vibrating element is pneumatically driven by compressed air.

[0124] Now for reference Figure 23The vibrating element 638 can be coupled to one or more outer walls 639 of the collecting vessel 620 (or any other vessel within the feeding system 600). In one embodiment, each of the vibrating elements 638 includes one or more attachment elements 641 for attaching the oscillator 643 to the outer wall 639 and a connection element 645 for coupling the vibrating element 638 to a suitable power source. The vibrating element 638 is configured to vibrate the outer wall 639 of the collecting vessel to pulse the nanoparticles and break up those nanoparticles that tend to clump together within the container 620. This allows the nanoparticles to detach from these clumps and fall into the lifter 204.

[0125] Now for reference Figure 8 and Figures 13-15 The lifter 604 is used to elevate nanoparticles exiting the container 620 from a first height to a second height greater than the first height. Nanoparticles are typically incapable of being conveyed because they have very little or no weight. Consequently, nanoparticles are prone to squeezing together and agglomerating at any type of opening to form clumps. The lifter 604 overcomes these problems by conveying and elevating the nanoparticles from the container 620 to the dispersion system 606.

[0126] In some embodiments, the lift 604 includes one or more delivery tubes 640 for conveying nanoparticles to a higher height without squeezing them back into clumps. In some embodiments, the tube 640 includes at least one segment extending at a transverse angle to the vertical direction (see [link to relevant documentation]). Figure 7 In other embodiments, pipe 640 includes at least one section substantially parallel to the vertical direction (see...). Figure 8 The lift 604 includes a plurality of discs 641 spaced apart from each other throughout the tube 640. The diameter of the discs 641 generally allows the discs 641 to pass through the tube 640 (i.e., slightly smaller than the inner diameter of the tube 640). Furthermore, the diameter of the discs 641 is close enough to the inner diameter of the tube 640 to define internal compartments 642 between adjacent discs 641. As each compartment 642 is conveyed through the tube 640, the discs 641 serve to isolate the interior of the compartment 642.

[0127] A tube 640 extends from the lower opening (not shown) in the collecting vessel 620 to the upper opening 650 of the funnel-shaped conveying vessel 652 in the dispersing device 606. For reasons discussed below, the vessel 652 is located above the vessel 620, and therefore, the tube 640 conveys and elevates the nanoparticles from a first height to a second height greater than the first height.

[0128] The elevator 604 also includes a cable 644 within a tube 640, through which compartment 642 is conveyed. In one embodiment, the cable 644 extends through each disc 641 within the tube 640 and is coupled to a suitable power source for moving the cable 644 (and the discs 641 therewith) through the tube. The tube 640 can extend upward from the vessel 620 to the dispersing device 606 and then downward back to the vessel 620 (see [link to original text]). Figure 7 The upward-moving compartment 642 typically contains nanoparticles, while the downward-moving compartment 642 is substantially free of nanoparticles. Alternatively, the tube 640 may be a continuous tube moving in one direction.

[0129] Refer again Figure 8 The lifting device 604 preferably includes a motor 649 coupled to the cable 644 for pushing the cable 644 through the feeding system 600 in one direction, so that the disc 641 is pushed in that direction. The motor 649 may include any suitable motor, such as a brushless DC motor, a permanent magnet DC motor, a stepper motor, a linear motor, a synchronous motor, an electromagnetic induction motor, a servo motor, a PMDC brushed motor, a shunt motor, a series motor, a compound motor, etc.

[0130] Cable 644 can be coupled to one or more drive wheels that redirect cable 644 within the feeding system 600. For example, as... Figure 8 As shown, cable 644 preferably extends substantially horizontally below bulk hopper 602 and is then reoriented to a vertical direction by first drive wheel 651 to lift nanoparticle agglomerates. Second drive wheel 653 is used to reorient cable 604 to a substantially horizontal direction, wherein cable 604 passes over container 652 to distribute nanoparticles into dispersion system 606.

[0131] The tube 640 includes one or more openings (not shown) aligned with openings in vessels 620 and 652 to allow nanoparticles to enter compartment 642 from vessel 620 and exit compartment 642 into vessel 652. In some embodiments, the opening located adjacent to vessel 620 is on the upper surface of the tube 640, while the opening located adjacent to vessel 652 is on the lower surface of the tube 640. Alternatively, the tube 640 may have a rotatable section allowing the opening to be moved from one configuration to another. Thus, nanoparticles can fall from vessel 620 into compartment 642 as a single compartment 642 passes through the opening below vessel 620. As compartment 642 continues to move upward along the tube 642, the inner wall of the tube 642 and the disc 641 of compartment 642 seal the interior of compartment 642, trapping the nanoparticles within. This allows the nanoparticles to be transported along the tube without being compressed into bundles or clumps.

[0132] Alternatively, the openings in tube 640 can be opened and closed. For example, lift 604 may include one or more actuators for opening and closing these openings in tube 640. Actuators may include any suitable mechanism, such as electronic actuators, pneumatic actuators, mechanical actuators, etc. In some embodiments, system 600 also includes a controller (not shown) for automatically opening and closing these openings at appropriate times or based on data obtained from sensors (i.e., opening when they pass under vessel 620 and then closing them as they move upward toward dispersing device 606). In other embodiments, system 600 may be mechanical elements that cooperate with each other to automatically open and / or close the openings as they pass through vessel 620 and dispersing device 606.

[0133] Figure 15 A cluster 647 of nanoparticles is shown, moved by a lift 604. As shown, each cluster 647 of nanoparticles is located in a compartment 642 between two disks 641 within a tube 640 of the lift 604. As the disks 641 are pushed through the tube 640, the clusters 647 of nanoparticles are moved along with them.

[0134] review Figure 8 The dispersion system 606 is used to control the delivery speed or flow rate of nanoparticles entering the filter media manufacturing system. Specifically, the dispersion system 606 ensures that an appropriate amount of nanoparticles are dispersed onto the fibers within the substrate. For example, the dispersion system 606 is configured to deliver nanoparticles at a specific mass or volumetric flow rate substantially consistent with the rate at which the feeder 200 advances the substrate from upstream to downstream. This ensures that a substantially constant amount of nanoparticles is dispersed throughout the various portions or sub-regions of the substrate, allowing the system to produce a relatively uniform filter media and reducing variability between filter media. The specific rate at which nanoparticles are dispersed into the substrate will depend on the desired specifications of the final filtered product, such as the preferred mass of nanoparticles dispersed in the volume or square area of ​​the filter media. In an exemplary embodiment, nanoparticles are dispersed into the moving substrate at a rate of about 0.1 g / m² to about 10 g / m², but it should be understood that this rate can vary depending on the specifications of the final product.

[0135] The advance rate of the substrate will depend on many factors in the manufacturing process, including the desired amount of nanoparticles dispersed into various regions of the substrate. In one embodiment, the advance rate of the substrate is from about 0.05 m / s to about 1 m / s.

[0136] The dispersion system 606 typically includes an upper funnel-shaped vessel 652 for collecting nanoparticles from a conveyor 604, a feed hopper 660, and one or more lower funnel-shaped vessels 670. For example... Figure 8 and Figure 16As shown, the upper funnel-shaped vessel 652 has an upper opening 650 coupled to an opening in the tube 640 of the elevator 604 and a lower opening 655 coupled to the feed hopper 660. The lower opening 655 has a much smaller cross-sectional area than the upper opening 653, allowing the nanoparticles to "leak" downwards to control the flow rate of the nanoparticles through the system. Similar to the collecting vessel 620, the vessel 652 may also include one or more vibrating elements that pulse the nanoparticles and prevent them from clumping together. These vibrating elements may, for example, be located on the outer wall of the vessel 652. Alternatively, the vibrating elements may be positioned inside the vessel 652 to facilitate the transport of nanoparticles through the vessel 652.

[0137] Now for reference Figure 19 The feed hopper 660 includes a first opening 661 for receiving nanoparticles from the vessel 652 and a second opening (not shown) for conveying the nanoparticles to the lower vessel 670. The feed hopper 660 also includes one or more mechanisms within the feed hopper 660 for conveying nanoparticles therethrough. Figure 18 and Figure 19 As shown, the feed hopper 660 preferably includes one or more rotating rollers 662 extending through the interior of the feed hopper 660. One or more rods 663 are coupled to the rollers 662 and configured to rotate with them to sweep nanoparticles downward through the feed hopper.

[0138] Now for reference Figure 8 and Figure 20 The feed hopper also includes a screw conveyor 664 for moving nanoparticles in a generally horizontal direction through the feed hopper 660 to the lower container 670. In a preferred embodiment, the screw conveyor 664 includes a plurality of curved blades 665 for receiving clusters of nanoparticles that have fallen vertically into the feed hopper 660 and redirecting these nanoparticles horizontally through the feed hopper 660. The curved blades 665 also control the volumetric flow rate of the nanoparticles through the feed hopper 660 and into the filter manufacturing system. The screw conveyor 664 can be driven by any suitable motor 666, such as any of the motors described above.

[0139] Now for reference Figure 8 and Figure 21The lower vessel 670 has an upper opening 672 coupled to an opening in the feed hopper 660 and a lower opening 676 coupled to the aforementioned fiber manufacturing system. The lower vessel 670 preferably has a substantially funnel-shaped form, such that the lower opening has a smaller cross-sectional area than the upper opening, to control the flow rate of nanoparticles through it. Similar to the collecting vessel 620, the lower vessel 670 may include one or more vibrating elements that pulse the nanoparticles and prevent them from clumping together. These vibrating elements may, for example, be located within the inner wall of the vessel 670. Alternatively, the vibrating elements may be positioned to facilitate the transport of nanoparticles through the vessel 670.

[0140] Now for reference Figure 22 The feed system 600 may further include a fine-tuning flow control device 680 that receives nanoparticles from the vessel 670 and provides final control over the volumetric flow rate of the nanoparticles entering the filter manufacturing apparatus. The flow control device 680 includes a funnel-shaped vessel 682 having an opening 684 for receiving nanoparticles from the vessel 670 and a lower opening (not shown) coupled to a feed tray 690. The feed tray 690 includes a feed channel 692 that tapers towards the opening 693. The opening 693 may be coupled to any suitable filter media manufacturing apparatus, such as any of the filter media manufacturing apparatuses described above, or other filter media manufacturing apparatuses that may be conceived by those skilled in the art.

[0141] Now for reference Figures 24-30 Representative filter media that can be manufactured from any of the systems described above will now be described. Figure 24 A representative filter medium or substrate 10 comprising a plurality of fibers 12 and nanoparticles 14, manufactured by the system and method described above, is shown. The substrate 10 has a first surface 16 and a second surface 18 opposite to the first surface 16, defining a width or thickness between the first surface 16 and the second surface 18. The nanoparticles 14 have been deposited into the substrate through the first surface 16. As shown, the nanoparticles 14 penetrate through the first surface 16 into the substrate 10 to a “certain depth” between the first surface 16 and the second surface 18. In some embodiments, the nanoparticles 14 penetrate from the first surface to at least 25% of the width or thickness between the first surface 16 and the second surface 18, or more preferably at least about 50% of the thickness. In other embodiments, the nanoparticles 14 substantially penetrate throughout the substrate 10 from the first surface 16 to the second surface 18.

[0142] Nanoparticles 14 preferably comprise individual nanoparticles that have been broken up, separated, and isolated from each other before being dispersed into the substrate 10, as discussed above. Thus, nanoparticles 14 do not exist in the fibrous product in the form of layers and do not have obvious clumps or bundles of nanoparticles. This allows the nanoparticles to be more dispersed throughout the substrate, which, in some applications (e.g., gas or air filters), provides more efficient filtration to remove contaminants. Furthermore, this results in a greater areal density (in grams per square meter (gsm)) or “addition amount” of the nanoparticles within the material. The term “addition amount” is used herein to refer to the areal density (gsm) of a material, fiber, or particle in a thin layer, sheet, or film of material.

[0143] In some implementations, the nanoparticles may contain approximately 0.1 g / m³. 2 Approximately 20 g / m 2 Preferably, it should be at least about 2.0 g / m 2 The specific amount added, or the areal density, may depend on the application. For example, the applicant has found that a higher areal density or addition amount will improve the efficiency of the filter media in removing contaminants. Therefore, the specific amount of nanoparticles added may depend on the desired efficiency of the filter media.

[0144] Figure 25 A filter medium or substrate 20 comprising a plurality of fibers 12 and nanoparticles 24, manufactured by the system and method described above, is shown. As shown, the nanoparticles 14 permeate the entire width of the substrate 20 from the first surface 16 to the second surface 18. In some embodiments, the nanoparticles 14 are substantially dispersed throughout the fibers 12 of the substrate, such as... Figure 25 As shown. In some embodiments, the density of nanoparticles located on the first surface 16 differs from the density of nanoparticles dispersed in the central portion of the substrate 20 between surfaces 16 and 18 by less than 50%. In some embodiments, this difference is less than 25%, preferably less than 10%. In some embodiments, the amount or number of individual nanoparticles dispersed in the central portion of the substrate 20 is at least about 50% of the amount of individual nanoparticles dispersed on or near the first surface 16, preferably at least about 75%, and more preferably at least about 90%.

[0145] In other embodiments, the nanoparticles 14 are arranged in a density gradient from the first surface 16 to the second surface 18. For example, Figure 26A substrate 30 is shown, wherein nanoparticles 14 form a density gradient, wherein the density of nanoparticles 14 disposed near a first surface 16 is higher than the density of nanoparticles 14 disposed near a second surface 18. In some embodiments, the difference between the density of nanoparticles located at the first surface 16 and the density of nanoparticles dispersed at the second surface 18 is greater than about 75%. In some embodiments, the difference is greater than 50%. In some embodiments, the difference is greater than 25%. In some embodiments, the amount or number of individual nanoparticles dispersed at or near the second surface 18 is less than about 50% of the amount of individual nanoparticles dispersed at or near the first surface 16, preferably less than about 25%, and more preferably less than about 10%.

[0146] Figure 25 The density gradient shown from the first surface 16 to the second surface 18 can be substantially linear. Alternatively, the density of the nanoparticles 14 can decrease from the first surface 16 to the second surface 18 in the form of a series of discrete steps, or the gradient can be random (i.e., the decrease in density is generally not linear or stepwise).

[0147] In other embodiments, nanoparticles may be added to the substrate from both the first and second surfaces 16, 18. In these embodiments, the areal density or "addition amount" at the first surface 16 and the second surface 18 may be substantially equal to each other, or they may vary depending on the application. In these embodiments, the areal density or "addition amount" in the middle of the substrate is lower than that at the surfaces 16, 18. For example, the areal density in the middle of the substrate may be about 75% of the areal density at the surfaces 16, 18, or it may be about 50%, 40%, or 25%.

[0148] Imaging techniques can be used, for example, to measure the distribution of nanoparticles across the thickness of the filter medium. A magnified image of the fiber product taken at a horizontal cross-section at the midpoint of the product's thickness using an electron microscope or other techniques can be compared to images taken at the top or bottom surface of the product, or all three images can be compared, to determine the degree of variation in the amount of deposited nanoparticles. Computer image analysis can be employed. For example, in... Figure 25In this process, cross-sections can be taken at point AA and at point BB. Top views of each cross-section can be obtained using electron microscopy, scanning electron microscopy, and other microscopes. For example, the top view of the cross-section taken at point AA can be compared with the top view taken at point BB. The number of microfibers, nanoparticles, or both in samples of the same two-dimensional size can be evaluated and compared. Furthermore, imaging techniques can be used on three-dimensional samples. These techniques can be used to evaluate fiber orientation and other properties. These techniques can be used to determine whether nanoparticles have been deposited to a certain depth in the substrate, substantially deposited in most of the substrate, substantially deposited throughout the entire depth of the substrate, or deposited at a certain depth in the substrate.

[0149] The fibers of the substrate under consideration can be manufactured by any method, including but not limited to thermal bonding, cellulose wet web forming, glass wet web forming, synthetic wet web forming, composite wet web forming, needle punching, melt blowing, air-blowing web forming, spinneret, gel spinning, melt spinning, wet spinning, dry spinning, island-type short fibers or spunbond, segmented disc short fibers or spunbond, etc. Such methods are described in U.S. Patent Nos. 4,406,950, 6,338,814, 6,616,435, 6,861,142, 7,252,493, 7,300,272, 7,309,430, 7,422,071, 7,431,869, 7,504,348, 7,774,077, 9,522,357, 9,993,761 and 2009 / 266,759, the full disclosures of which are incorporated herein by reference for all purposes.

[0150] The fibers under consideration can have a variety of cross-sectional shapes, including but not limited to circular, bean-shaped, dogbone-shaped, trefoil-shaped, barbell-shaped, bowtie-shaped, star-shaped, Y-shaped, etc. These shapes and / or other conventional shapes can be used in various embodiments to obtain the desired performance characteristics. The fibers in the substrate are held together by thermal bonding, chemical bonding, entanglement, or the use of adhesives (such as glues).

[0151] The fiber can be a man-made fiber or a natural fiber. Suitable materials for fibers include, but are not limited to, metal fibers, carbon fibers, polypropylene (PP), polyester (PET), PEN polyester, PCT polyester, polybutene (PBT), ethylene polyester (PET), polylactic acid (PLA), polyamide (PA), copolyamide, polyethylene, high-density polyethylene (HDPE), low-density polyethylene (LLDPE), cross-linked polyethylene, polycarbonate, polyacrylate, polyacrylonitrile, polyfuran, polystyrene, styrene-maleic anhydride, polymethylpentene, cyclic olefin copolymers or fluorinated polymers, polytetrafluoroethylene, perfluoroethylene and hexafluoropropylene or copolymers with PVDF (such as P(VD)). F-TrFE) or terpolymers (such as P(VDF-TrFE-CFE)), propylene, polyimide, polyetherketone, cellulose esters, nylon and polyamide, polymethacrylic acid, poly(methyl methacrylate), polyoxymethylene, polysulfonate, acrylic acid, styrene-acrylic acid, pre-oxidized acrylic acid, fluorinated acrylic acid, vinyl acetate, vinyl acrylic acid, ethylene vinyl acetate, styrene-butadiene, ethylene / vinyl chloride, vinyl acetate copolymers, latex, polyester copolymers, carboxylated styrene acrylic acid or vinyl acetate, epoxy resins, acrylic multipolymers, phenolic resins, polyurethane, cellulose, styrene, or any combination thereof. Other conventional fibrous materials were also considered.

[0152] The fibers can include fibers of varying sizes, typically having a diameter of about 1 to about 1000 micrometers and a length of about 1 / 2 to 3 inches. The fibers can be configured as a gradient density medium, where the pore size decreases from the upper surface (upstream) to the lower surface (downstream) of the filter to increase capture efficiency and dust holding capacity. This configuration also allows for the dispersion of different amounts of nanoparticles into the filter medium at different depths. For example, the upstream side of the filter medium can have the largest fiber size to allow for more void space and a higher nanoparticle density, while the downstream side of the filter medium has smaller fibers to provide a lower nanoparticle density. Alternatively, this structure can be inverted to provide a higher nanoparticle density in the downstream portion of the filter medium.

[0153] Fibers in the medium can be held together by thermal bonding, chemical bonding, or entanglement. Bicomponent fibers can be used, particularly in mechanical filtration, and these fibers are formed by extruding two polymers from the same spinneret, both polymers being contained within the same filament. Suitable materials for bicomponent fibers include, but are not limited to, polypropylene (PP) / polyethylene (PE), polyethylene terephthalate (PET) / polypropylene (PP), etc.

[0154] In some embodiments, the substrate may include a “high-loft” filter medium comprising spunbonded or hot-air bonded carded fibers. As used herein, the term “high-loft” refers to a void volume greater than the total solids volume. In hot-air bonded carded nonwoven fibers, the loft of the substrate can be controlled in various ways known to those skilled in the art. For example, loft can be increased by applying less compressive force to the medium during the bonding process. In another instance, high-loft nonwoven materials can be manufactured using fibers with a greater thickness (e.g., greater than 3 denier, such as 5 denier or greater, 6 denier or greater) (discussed in more detail below). In other embodiments, loft can be increased by using non-concentric bio-component fibers, as discussed in more detail below.

[0155] In some embodiments, the fibers may include a silicone-based coating to improve the efficiency of the filter media in capturing contaminants, particularly those in the E2 and E3 particulate groups. The silicone-based coating may include a reactive silicone emulsion. Silicone emulsions may include, for example, dimethyl silicone emulsions, amino-based silicone emulsions, organofunctional silicone emulsions, resin-based silicone emulsions, film-forming silicone emulsions, etc. In one embodiment, the reactive silicone emulsion comprises an amino-functionalized polydimethylsiloxane and / or polyethylene glycol monotridecyl ether. Suitable silicone coatings are described in commonly assigned U.S. Provisional Patent Application No. 63 / 406,686, filed September 14, 2022, the entire disclosure of which is incorporated herein by reference.

[0156] Filter media may contain charge additives to alter the triboelectric charge of the fibers and increase the stability and / or duration of the triboelectric charge in the filter. This improves the overall filtration efficiency of the filter without compromising other important filter characteristics, such as lifespan, dust holding capacity, and pressure drop or airflow through the filter. A description of charge additives suitable for triboelectric charging is given in commonly assigned Provisional Patent Application No. 63 / 410,731, filed September 28, 2022, the entire disclosure of which is incorporated herein by reference for all purposes.

[0157] The fibers can have a thickness suitable for the application. In some embodiments, the fiber has at least one dimension having a size of about 1 to about 10,000 micrometers, or about 1 to about 1,000 micrometers, or about 10 to 100 micrometers. The thickness of the fiber can also be measured in deniers, which is a unit of measurement for the linear mass density of the fiber. In some embodiments, the linear density of the fiber can be about 1 denier to about 10 deniers. Nanoparticles are fibers with at least one dimension having a size of about 1 to about 1,000 nanometers, or about 1 to about 100 nanometers. The dimensions of the aforementioned fibers and nanoparticles can be diameter or width, depending on the shape of the fiber or nanoparticle.

[0158] For gas filters, such as pleated or non-pleated air filters, the linear density of the fibers can be from about 1 denier to about 10 denier. The filter media can contain fibers with the same or different linear densities.

[0159] The linear density of fibers in air filters is typically around 3 denier or less to ensure the fibers are small enough to capture contaminants passing through the filter. The applicant unexpectedly discovered that by using nanoparticles dispersed in the filter media, fibers can have much higher linear densities, for example, greater than 3 denier. This is because the nanoparticles provide significant filtration capacity. In some cases, the linear density of the fibers can be greater than 3 denier, 5 denier or more, 6 denier or more, or even as high as 7-10 denier.

[0160] The applicant has also discovered that, in some applications, fibers with a greater linear density (e.g., greater than about 3 denier) than those used in conventional filters provide more open spaces or pores in the filter media, allowing nanoparticles to be dispersed therein at a greater density. While this may seem counterintuitive to those skilled in the art, the applicant has found that fibers with a greater linear density incorporating nanoparticles actually improve the overall efficiency of the filter.

[0161] In some embodiments, the filter medium may include at least two different fiber thicknesses or linear densities to provide at least two different filter layers within the same filter medium. For example, in some cases, a portion of the filter medium will include fibers with a linear density greater than 3 denier, such as 5 denier or greater, or 6 denier or greater. Another portion of the filter medium will include fibers with a more standard linear density of 3 denier or less. This dual-layer filter medium creates a first filtration section and a second filtration section, the first filtration section primarily utilizing high-density nanoparticles within the thicker fibers to filter contaminants, and the second filtration section primarily utilizing fibers with a lower linear density to filter contaminants, but both sections may contain nanoparticles dispersed throughout the fibers. In some embodiments, the filter medium may include three or more separate sections or layers, each with a different denier fiber range.

[0162] Figure 27A dual-layer filter medium is shown, comprising a first substrate 40 having a first surface 42 and a second surface 44 opposite to the first surface; and a second substrate 50 having a first surface 52 and a second surface 54 opposite to the first surface. The second surface 44 of the substrate 40 is bonded to the second surface 54 of the first substrate in any manner known to those skilled in the art. The first substrate 40 comprises fibers 46 with a relatively low linear density (e.g., about 3 denier or less). The second substrate 50 comprises fibers 56 with a relatively high linear density (e.g., about 3 denier or greater, such as 5 denier, 6 denier or greater). The second substrate 50 also comprises individual nanoparticles 58 dispersed throughout and bonded to the fibers 56 and / or retained by the second substrate 50. The first substrate 40 may or may not contain nanoparticles.

[0163] The first substrate 40 is configured to primarily utilize fibers 46 to filter contaminants, but as previously mentioned, the first substrate 40 may also contain nanoparticles. The second substrate 50 is configured to utilize both fibers 56 and nanoparticles 58 to filter contaminants.

[0164] In some embodiments, the substrate may contain additives, such as antibacterial and / or antiviral compositions, such as silver, zinc, copper, silicone, tributyltin, or organic compounds containing chlorine, bromine, or fluorine compounds.

[0165] Fibers can include biological component fibers, which comprise two or more different fibers bonded together. Fibers can contain the same or different materials.

[0166] In some embodiments, the filter media (i.e., fibers and / or nanoparticles) may be electrostatically charged, enabling the capture of contaminants, for example, by mechanical and electrostatic filtration. The bond between the fibers and nanoparticles can also be enhanced by electrostatically charging the nanoparticles, fibers, or both. For example, in some embodiments, the fibers are electrostatically charged, allowing mechanical filtration through the nanoparticles while simultaneously enabling electrostatic filtration through an electret substrate. The electrostatic or electret substrate may be a highly porous triboelectric filter media manufactured by carding and needle punching. In one embodiment, it is preferable to deposit the nanoparticles into the substrate prior to needle punching, and then needle the electrostatic fibers and nanoparticles together.

[0167] Electrostatic charging of substrates, nanoparticles, or both can be performed using triboelectric methods, corona discharge, electrostatic fiber spinning, hydrocharging, charging rods, or other known methods. Corona charging is suitable for charging single polymer fibers or fiber blends or fabrics. Triboelectric charging can be applied to charging fibers with different electronegativity. Electrostatic fiber spinning combines polymer charging and fiber spinning into a one-step process. A description of charge additives suitable for triboelectric charging is provided in commonly assigned Provisional Patent Application No. 63 / 410,731, filed September 28, 2022, the entire disclosure of which is incorporated herein by reference for all purposes.

[0168] Nanoparticles with different triboelectric properties relative to fibers can be selected to enhance particle removal by utilizing the triboelectric effect. In this method, the generated nanoparticles are formed in an electric field and are less susceptible to contamination by chemicals that can mitigate the triboelectric effect. Nanoparticles with different adsorption properties or surface charge characteristics than coarse fibers can also be used, for example, for oil or water filtration. This difference can be used to enhance or create a local electric field gradient within the filter media to enhance particle removal. Nanoparticles and coarse fibers can have different wetting properties.

[0169] In some implementations, the filter media discussed herein can be part of a filtration device that captures or absorbs contaminants, such as a liquid filter, a gas filter for household and commercial air filtration, a surgical mask, or other face mask. This filtration device can be a mechanical filter, adsorption filter, isolation filter, ion exchange filter, reverse osmosis filter, surface filter, depth filter, etc., and can be designed to remove many different types of contaminants from air, water, etc.

[0170] In one such embodiment, filter media are incorporated into an air filter that removes particles and contaminants from the air, such as HEPA filters (i.e., pleated mechanical air filters), HVAC filters, UV light filters, electrostatic filters, washable filters, media filters, rotating glass filters, pleated or non-pleated air filters, activated carbon filters, pocket filters, V-bank compact filters, filter discs, flat unit filters, cartridge filters, etc. The filter media may include filter media for air filters and may be supported by a support layer, a loosely woven fabric layer, or may be included in other layers or materials. The applicant has found that, as discussed herein, incorporating nanoparticles to a certain depth into the filter media significantly improves the efficiency of the air filter without compromising other factors, such as pressure drop across the filter (i.e., airflow). Furthermore, these materials increase the overall dust holding capacity, thereby increasing the filter's lifespan, particularly compared to filters that rely solely or primarily on electrostatic interactions to improve efficiency.

[0171] Conventional residential and commercial air filters, such as HEPA and HVAC filters, are typically rated based on their ability to capture particles ranging from approximately 0.3 to 10 micrometers. This rating, known as the Minimum Efficiency Reported Value or MERV, is established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). MERV ratings range from 1 to 16, with higher numbers indicating greater efficiency in capturing a specific type of particle. Conventional mechanical air filters typically report a MERV rating of around 8 for fiber filter media.

[0172] Air filters are typically rated based on their initial efficiency (i.e., the efficiency of the air filter before use) and their efficiency over time and use. The latter efficiency is usually tested through conditioning procedures, see ASHRAE Standard 52.2 Appendix J.

[0173] The air filters described herein have an initial MERV rating greater than about 10 and a pressure drop less than about 0.5 inches of water column. In some cases, the initial MERV rating is about 11 with a pressure drop equal to or less than about 0.17 inches of water column, or the initial MERV rating is about 13 with a pressure drop equal to or less than about 0.36 inches of water column, or the initial MERV rating is about 14 with a pressure drop equal to or less than about 0.5 inches of water column.

[0174] The gas filters described herein have a MERV rating of 10 or higher after conditioning in accordance with Annex J of ASHRAE Standard 52.2. In some embodiments, the gas filters have a MERV rating of 13 or higher after conditioning using ASHRAE Standard 52.2, ISO Standard 16890, or any other acceptable industry standard.

[0175] The MERV rating of the fiber filter media discussed in this article varies depending on many factors, including the type and size of the fibers used in the filter media, the density of individual nanoparticles in the filter media, the width of the filter media, and the number and size of pleats (if any). The MERV rating can be measured for both sheet fiber products and fiber products formed as pleated filter media, and the pressure drop can differ for each product. Similarly, the pressure drop across the filter media also depends on many factors, including those mentioned above.

[0176] One factor affecting MERV rating and pressure drop is the density or amount of nanoparticles within the substrate relative to the density of fibers within the substrate. The applicant has found that the lower the ratio between substrate density and nanoparticle density, the higher the MERV rating and the higher the pressure drop of the filter. In some embodiments, the filter media described herein have a nanoparticle areal density of about 0.1 g / m² to about 20 g / m², preferably at least about 2 g / m².

[0177] In some cases, the density of the nanoparticles will also depend on the density of the actual filter media (i.e., the density of the coarse fibers). As discussed in more detail below with reference to Table 2, a density ratio of approximately 67 (substrate gsm divided by the added nanoparticle gsm) results in a pressure drop of approximately 0.14 inches of water column and an initial MERV rating of 10. A density ratio of approximately 33.4 increases the MERV rating to 10 while only increasing the pressure drop to approximately 0.17. A density ratio of approximately 22.3 increases the initial MERV rating to approximately 12 with a pressure drop of approximately 0.24 inches of water column.

[0178] Therefore, the filter efficiency or MERV rating can be improved with increasing nanoparticle addition. In particular, the applicant found that, for example, an addition amount of at least 2 g / m³... 2 At this time, a filter with a MERV level of approximately 10 can be achieved. 4 or 6 g / m 2 The addition amounts provided filters with MERV grades of approximately 12 and 13, respectively. 10 g / m³ 2 Or higher additions resulted in filters with a MERV rating of 15 or higher.

[0179] The applicant also discovered that incorporating fibers with greater thickness or linear density results in larger pore sizes, leading to larger pore volumes, which in turn allows for higher densities of nanoparticles within the substrate. This results in higher MERV ratings and pressure drops (as discussed in Table 2 below with reference to the table). For example, the applicant was able to manufacture an air filter with a MERV rating of 14 and a pressure drop of 0.5 inches of water column using 5-denier bio-component fibers. Similarly, the applicant was able to manufacture a filter with a MERV rating of 13 and a pressure drop of only about 0.29 inches of water column using 5-denier bio-component fibers.

[0180] The fiber products disclosed herein can be used in medical face masks or other medical applications, such as filter cartridges in ventilators. Medical face masks are designed to protect healthcare workers and / or patients from microorganisms and other substances. For example, medical face masks can block bacteria (e.g., those approximately 3 micrometers in size) and viruses (e.g., those approximately 0.1 micrometers in size). The face mask is made using a multi-layered filter medium and has ear loops, straps, or other structures for attaching the face mask to the face. Wires can be incorporated into at least the upper part of the face mask so that at least that portion conforms to the face. The face mask may include a rigid polymer structure designed to hold the multi-layered filter medium in front of the face. In one example, the face mask has three layers. The outer and inner layers contain a filter medium (e.g., spunbond polypropylene) that provides breathability, but any material mentioned herein may also be used. An intermediate layer is disposed between the inner and outer layers and comprises a microfiber substrate having nanoparticles deposited to a certain depth within the substrate to provide an initial MERV greater than 8, preferably greater than 10, and more preferably 13 or greater. The pressure drop through the mask is 3 to 6 mm water column, more preferably 4 mm water column for breathability. The desired efficiency of the mask is approximately 95%. Other examples of the mask have four or more layers. Multi-layer fiber products can be combined into a single mask.

[0181] In some embodiments, the filter medium may be included in a film or layer having pores, gaps, or perforations. The pores may be embossed into a pattern (e.g., circular, rhomboid, hexagonal, rectangular, triangular, etc.) and then stretched until pores are formed in the thinned areas created by the embossing. This open-cell substrate may be formed from a variety of polymers (e.g., polypropylene, polyethylene, high-density polyethylene (“HDPE”), etc.). The polymer layer may, for example, include an extruded membrane. Open-cell membranes are commercially available and sold under the trademark Delnet®. The substrate is provided in the form of rolls into which nanoparticles are deposited in a roll-to-roll process.

[0182] In other embodiments, the gas filter includes a filter medium and a substantially rigid support layer bonded to the filter medium. The support layer comprises fibers and individual nanoparticles dispersed at a certain depth within the layer. The nanoparticles are configured to filter contaminants that pass through the support layer.

[0183] Figure 28A filter product 700 is shown, comprising a filter medium 710 including fibers 722 and nanoparticles 720 dispersed in at least a portion of the filter medium 710. As shown, the filter medium 710 has a first upper surface 712 and a second lower surface 714. The nanoparticles are dispersed through the upper surface 712 such that they extend beyond the upper surface 712 and penetrate to a certain depth into the filter medium 710, as discussed above. The filter product 700 also includes a support layer 730, which can be any suitable support layer known in the art, such as a substantially rigid polymer providing support for the filter medium 710, or an open-pore membrane having multiple pores for gas or fluid to pass through (as discussed above).

[0184] Figure 29 Another filtration product 740 is shown, which includes a filter medium 710 comprising fibers 722 and nanoparticles 720 dispersed in a portion of the filter medium 710. In this embodiment, product 740 includes a loosely woven fabric layer 750 bonded to a support layer 730.

[0185] Figure 30 A dual-layer filtration product 760 is shown, comprising a first filter medium 762 and a second filter medium 764 bonded together. As shown, nanoparticles 720 are dispersed at a certain depth in each filter medium 762, 764. In this embodiment, the nanoparticles 720 are dispersed through the inner surfaces 766, 768 of the filter media 762, 764. In another embodiment (not shown), the nanoparticles are dispersed through the outer surfaces 770, 772 of the filter media 762, 764. In yet another embodiment, the nanoparticles 720 may be deposited on the inner surface 766 of the medium 762 and the outer surface 772 of the medium 764.

[0186] Example 1 A microfiber substrate consisting of bicomponent fibers with an inner circular portion of polyester and an outer concentric portion of HDPE is provided in the form of a roller. In a roller-to-roll process, the substrate is sprayed with an adhesive and biosoluble glass fiber nanoparticles or nanoparticles are deposited. The nonwoven product is then placed in an oven for heating, and the cooled nonwoven product is collected onto another roller.

[0187] According to the following Figures 12-16 The process described herein deposits nanoparticles. In the experiments, biosoluble glass nanoparticles were used. The nanofibers had a diameter of approximately 700 nm and a length of approximately 500 micrometers. In the following examples, a carded hot-air bonded nonwoven fabric made of bicomponent fibers was used as the substrate: The flat-plate filter media samples were tested at a filtration rate of 110 fpm. The sample size was 12” × 12”. NaCl salt particles ranging from 0.3 to 10 micrometers were used as contaminants.

[0188] Example 2 A carded nonwoven fabric made of 3-denier PET / PE bicomponent fibers was used as the substrate. A composition containing water, 2-hexyloxyethanol, isopropanolamine, sodium dodecylbenzenesulfonate, laurylamine oxide, and ammonium hydroxide was used as the binder. The amount of nanofibers added was controlled by adjusting the linear speed.

[0189] Table 1

[0190] This example demonstrates that by controlling the amount of nanoparticles added, the MERV grade can be improved from MERV 7 to MERV 13.

[0191] Example 3 A high-loft hot-air bonded combed nonwoven fabric with 5-denier bicomponent fibers was used as the substrate. A typical starch binder was diluted and sprayed on before nanofiber deposition. The starch fully bonded the nanoparticles as the solvent evaporated and dried under an IR heater.

[0192] Table 2

[0193] Example 4 Spunbond or meltblown media were used as the substrate, in which nanoparticles were incorporated into the substrate after IPA emission, as described herein. Spunbond fibers were made from a melt polymer that was spun and stretched to produce filaments. The average basis weight of the substrate was approximately 90 gsm, and the average thickness was approximately 0.57 mm. Base samples without any nanoparticles were used. Four separate samples were prepared, incorporating nanoparticles incorporated into the substrate, as described herein. In sample 2, nanoparticles were incorporated into the meltblown fiber after IPA emission. In samples 1, 3, and 4, nanoparticles were incorporated into the spunbond fiber after IPA emission. The results of this test are shown in Table 3 below.

[0194] Table 3

[0195] As shown, in all three particle groups, the filter media samples incorporating nanoparticles exhibited higher efficiency than the baseline samples, with significant improvements in efficiency observed in particle groups E2 and E3. Using nanoparticles, the overall MERV rating of the samples improved from MERV 7 (base samples) to MERV 12 through MERV 16. The pressure drop of the baseline samples without nanoparticles was 0.07 inches of water. The pressure drops of samples 1–4 increased slightly, ranging from 0.17 to 0.41 inches of water. In sample 2, where nanoparticles were incorporated into meltblown fibers, the MERV rating was 14 and the pressure drop was 0.24 inches of water.

[0196] Example 5 5-denier hot-air bonded carded fibers were used as the substrate. A base sample without nanoparticles was used. Two separate samples were prepared, each incorporating nanoparticles into the substrate as described herein. The results of this testing are shown in Table 4 below.

[0197] Table 4

[0198] As shown, in all three particle groups, the filter media samples incorporating nanoparticles exhibited significantly improved efficiency compared to the baseline samples. Using nanoparticles, the overall MERV grade of the samples improved from MERV 6 (base sample) to MERV 13. The pressure drop of the baseline sample without nanoparticles was 0.03 inches of water. The pressure drops of samples 1 and 2 increased slightly, from 0.31 to 0.33 inches of water.

[0199] Example 6 Meltblown fibers were used as the substrate. The average basis weight of the substrate was approximately 24 gsm and the average thickness was approximately 0.4 mm. Base samples without nanoparticles or adhesives (e.g., PVOH) were used. Sample 1 consisted of meltblown fibers with the strip side facing up. PVOH was sprayed onto the fibers, but no nanoparticles were incorporated. Sample 2 consisted of meltblown fibers with the pile side facing up. PVOH was sprayed onto the fibers, but no nanoparticles were incorporated. Sample 3 consisted of meltblown fibers with PVOH sprayed onto them, and nanoparticles were incorporated into the fibers, as described herein. The results of this test are shown in Table 5 below.

[0200] Table 5

[0201] As shown, in all three particle groups, especially in the E1 particle group, the efficiency of Sample 3, which incorporates nanoparticles, is increased compared to the other three base samples. The overall MERV grade of Sample 3 improves from MERV 13 or 14 (base samples) to MERV 15 (using nanoparticles). Adding PVOH to Samples 2 and 3 does not significantly increase the pressure drop (i.e., 0.35 for the base samples, 0.38 and 0.41 for Samples 1 and 2, respectively). The pressure drop of Sample 3 does increase from approximately 0.40 inches of water column to approximately 1 inch of water column. In Sample 3, where nanoparticles are incorporated into meltblown fibers, the MERV grade is 15 and the pressure drop is 1.02 inches of water column.

[0202] Example 7 5-denier hot-air bonded carded fibers were used as the substrate. A base sample without nanoparticles was used. Seven additional samples were prepared, including 5-denier carded fibers with nanoparticles incorporated into the substrate, as described herein. The results of this testing are shown in Table 6 below.

[0203] Table 6

[0204] As shown, in all three particle groups, particularly in the E2 and E3 particle groups, the efficiency of the seven samples incorporating nanoparticles was higher than that of the base sample. The overall MERV grade improved from MERV 6 (base sample) to MERV 7 to MERV 13 (using nanoparticles). The pressure drop increased only from 0.03 inches of water column to a maximum of 0.32 inches of water column.

[0205] Example 8 High-bulk spunbond fibers were used as the substrate in a continuous fiber production line. This experiment included two different versions: 205-6 and 205-2, with variations in the setup on the continuous fiber production line to produce two substrates of different weights and thicknesses. Each version (205-6 and 205-2) used a base sample without nanoparticle incorporation. Six additional samples were prepared, including 205-6 and 205-2 fibers as well as those with nanoparticles incorporated into the substrate, as described herein. The results of this test are shown in Table 7 below.

[0206] Table 7

[0207] As shown, in all three particle groups, the efficiency of all six samples incorporating nanoparticles was significantly improved compared to the base sample. The overall MERV grade improved from MERV 6 (base sample) to MERV 11 to MERV 14 (using nanoparticles). The pressure drop increased only from 0.04 inches of water column to a maximum of 0.87 inches of water column. The pressure drop in sample 205-2 increased only to a maximum of 0.48 inches of water column.

[0208] Example 9 Spunbond and meltblown fibers were used as substrates. For spunbond fibers, the average basis weight of the substrate was approximately 70 gsm, while for meltblown fibers, the average basis weight was approximately 24 gsm. The average thickness of the substrate was approximately 0.75 mm. Base samples without nanoparticle incorporation were used. Five additional samples were prepared, including spunbond and meltblown fibers with nanoparticles incorporated into the fibers, as described herein. In samples 1-3, nanoparticles were sprayed onto meltblown fibers. In samples 4 and 5, nanoparticles were sprayed onto spunbond fibers. Furthermore, in samples 1 and 2, the adhesive PVOH was not sprayed onto the substrate. PVOH was sprayed onto samples 3-5. The results of this test are shown in Table 8 below.

[0209] Table 8

[0210] As shown, in all three particle groups, the efficiency of all five samples incorporating nanoparticles was significantly improved compared to the base sample. The overall MERV rating improved from MERV 5 (base sample) to MERV 16 (using nanoparticles). The pressure drop increased only from 0.07 inches of water column to a maximum of 0.56 inches of water column. In samples 3-5 (PVOH sprayed onto the substrate), the pressure drop increased only to a maximum of 0.4 inches of water column.

[0211] Example 10 5-denier hot-air bonded combed glass fiber was used as the substrate. A base sample without nanoparticles was used. Three additional samples were prepared, including 5-denier combed glass fiber and samples with nanoparticles incorporated. The results of the tests are shown in Table 9 below.

[0212] Table 9

[0213] As shown, in all three particle groups, the efficiency of the three samples incorporating nanoparticles was significantly improved compared to the base sample. The overall MERV grade improved from MERV 6 (base sample) to MERV 12 or MERV 13 (using nanoparticles). The pressure drop increased only from 0.03 inches of water column to a maximum of 0.27 inches of water column.

[0214] Example 11 A blend of 5-denier and 7-denier hot-air bonded combed glass fibers was used as the substrate. The medium was hot-air bonded. A base sample without nanoparticles was used. Nineteen additional samples were prepared, including blends of 5-denier and 7-denier combed glass fibers with nanoparticles incorporated therein. The results of the tests are shown in Table 10 below.

[0215] Table 10

[0216] As shown, in all three particle groups, the efficiency of all 19 samples incorporating nanoparticles was significantly improved compared to the base sample. The overall MERV grade improved from MERV 6 (base sample) to MERV 10 to MERV 13 (using nanoparticles) (most samples were graded MERV 13). The pressure drop increased only from 0.03 inches of water column to a maximum of 0.31 inches of water column.

[0217] While the apparatus, system, and method have been described in detail herein with respect to certain preferred embodiments, many modifications and variations can be made therein by those skilled in the art. Therefore, the above description should not be construed as limiting, but rather as including such obvious variations as described above, and is limited only by the spirit and scope of the appended claims.

[0218] For example, in a first aspect, a first embodiment includes a system for manufacturing a filter medium. The system includes: a feeder for advancing a fiber-containing substrate from an upstream end to a downstream end; a dispersion device for dispersing nanoparticles into the substrate to form a filter medium as the substrate is advanced by the feeder; a container for receiving clusters of nanoparticles; and a feeding system for conveying the clusters of nanoparticles from the container to the dispersion device.

[0219] The second embodiment includes the first embodiment, wherein the feeding system is configured to deliver nanoparticle clusters to the dispersion device at a controlled rate.

[0220] The third embodiment includes any combination of the first two embodiments, wherein the feeding system is configured to deliver nanoparticle clusters to the dispersion device at a controlled volumetric flow rate.

[0221] The fourth embodiment includes any combination of the first three embodiments, wherein the feeding system is configured to separate nanoparticle clusters into smaller nanoparticle aggregates.

[0222] The fifth embodiment includes any combination of the first four embodiments, wherein the feeding system is configured to separate nanoparticle clusters into individual nanoparticles.

[0223] The sixth embodiment includes any combination of the first five embodiments, wherein the feeding system is configured to transport nanoparticle clusters from the container to the dispersion device at a rate of about 0.05 m / s to about 1.0 m / s.

[0224] The seventh embodiment includes any combination of the first six embodiments, wherein the nanoparticles are dispersed in the substrate at a ratio of about 0.1 g / m² to about 10 g / m².

[0225] The eighth embodiment includes any combination of the first seven embodiments, wherein the container includes a bulk bin for receiving nanoparticle clusters, wherein the bulk bin includes one or more rotors within the bulk bin for conveying nanoparticle clusters through the bulk bin.

[0226] The ninth embodiment includes any combination of the first eight embodiments, wherein the feeding system further includes a lift for conveying the nanoparticle clusters from a first height in the bulk silo to a second height greater than the first height.

[0227] The 10th embodiment includes any combination of the first 9 embodiments, wherein the elevator includes a tube having a plurality of discs disposed within the tube, the discs defining internal compartments within the tube for containing clusters of nanoparticles.

[0228] The 11th embodiment includes any combination of the first 10 embodiments, and also includes an energy source coupled to the lift for moving the disc from a first height to a second height through the tube.

[0229] The 12th embodiment includes any combination of the first 11 embodiments, wherein the feeding system further includes a feeding hopper coupled to the elevator at a second height.

[0230] The 13th embodiment includes any combination of the first 12 embodiments, wherein the feed hopper includes one or more rotating elements for conveying nanoparticle clusters through the feed hopper to the dispersion device.

[0231] The 14th embodiment includes any combination of the first 13 embodiments, wherein one or more rotating elements include a helical thruster.

[0232] The 15th embodiment includes any combination of the first 14 embodiments, wherein the feeding system includes one or more vibrating elements for conveying nanoparticle clusters through the feeding system.

[0233] The 16th embodiment includes any combination of the first 15 embodiments, and also includes a collection vessel disposed between the bulk silo and the elevator, the collection vessel including one or more vibrating elements for vibrating the nanoparticles to separate the nanoparticles from the wall of the collection vessel.

[0234] The 17th embodiment includes any combination of the first 16 embodiments, wherein the dispersing device includes a nozzle configured to disperse nanoparticles onto a first surface of the substrate such that the nanoparticles at least penetrate through the first surface of the substrate.

[0235] The 18th embodiment includes any combination of the preceding 17 embodiments, and also includes a fiberizing device disposed between the feeding system and the dispersing device for substantially converting the nanoparticle clusters into individual nanoparticles.

[0236] The 19th embodiment includes any combination of the first 18 embodiments, wherein the individual nanoparticles are spaced apart from each other and at least one dimension has a size of less than 1 micrometer.

[0237] On the other hand, a filter medium is provided which is manufactured from any combination of the first 19 embodiments.

[0238] On the other hand, a filter is provided that can be manufactured from any combination of the first 19 embodiments.

[0239] In another embodiment, the first embodiment includes a system for manufacturing a filter medium. The system includes: a container for receiving a plurality of nanoparticles at a first height; a lifter coupled to the container for lifting the nanoparticles from the first height in the container to a second height greater than the first height; and equipment coupled to the lifter at the second height and including one or more components for bonding the nanoparticles with fibers to form a filter medium.

[0240] The second embodiment is the first embodiment, wherein the lifter includes a tube having a plurality of discs configured to move through the tube, wherein each disc has an outer diameter smaller than the inner diameter of the tube.

[0241] The third embodiment is any combination of the first two embodiments, wherein the disks define compartments between the disks for containing and transporting nanoparticles.

[0242] The fourth embodiment is any combination of the first three embodiments, wherein the disc can move within the tube between the first and second heights.

[0243] The fifth embodiment is any combination of the first four embodiments, wherein the tube includes an opening for receiving nanoparticles from the container.

[0244] The sixth embodiment is any combination of the first five embodiments, and also includes a dispersion system disposed between the elevator and the device, the dispersion system having an upper opening, wherein the tube has a second opening aligned with the upper opening of the dispersion system for conveying nanoparticles from the elevator to the dispersion system.

[0245] The seventh embodiment is any combination of the first six embodiments and also includes cables coupled to the disk for advancing the disk from the first height to the second height.

[0246] The eighth embodiment is any combination of the first seven embodiments, wherein the disc advances at an angle transverse to the vertical axis of the container.

[0247] The ninth implementation is any combination of the first eight implementations, wherein the disk edge advances in a direction substantially perpendicular to the vertical axis.

[0248] The 10th implementation is any combination of the first nine implementations, and also includes a motor coupled to the cable for propelling the cable through the tube.

[0249] The 11th embodiment is any combination of the first 10 embodiments, wherein the container includes a bulk bin for containing nanoparticles and has an opening at the lower end of the bulk bin, wherein the bulk bin includes one or more rotors disposed inside the bulk bin.

[0250] The 12th embodiment is any combination of the first 11 embodiments, wherein each rotor includes one or more rotating blades for mechanically separating nanoparticle clusters into smaller nanoparticle aggregates.

[0251] The 13th embodiment is any combination of the first 12 embodiments, wherein the rotor is configured to rotate about an axis tangential to the height of the container.

[0252] The 14th embodiment is any combination of the first 13 embodiments, wherein at least some rotors rotate clockwise and at least some rotors rotate counterclockwise.

[0253] The 15th embodiment is any combination of the first 14 embodiments, wherein the device includes a nozzle for dispersing nanoparticles onto a first surface of a fiber-containing substrate, such that the nanoparticles penetrate at least through the first surface of the substrate.

[0254] The 16th embodiment is any combination of the first 15 embodiments and also includes a fiberization device configured to separate individual nanoparticles from the nanofiber clusters.

[0255] The 17th embodiment is any combination of the first 16 embodiments and also includes a lifting belt for advancing the substrate to the adjacent nozzle.

[0256] The 18th embodiment is any combination of the preceding 17 embodiments, and also includes a coating device for dispersing the adhesive onto fibers in a substrate.

[0257] The 19th embodiment is any combination of the first 18 embodiments, and also includes a dryer disposed near the feeder between the housing and the downstream end of the feeder for heating nanoparticles and fibers.

[0258] The 20th embodiment is any combination of the first 19 embodiments, wherein the individual nanoparticles are spaced apart from each other and at least one dimension has a size of less than 1 micrometer.

[0259] On the other hand, a filter medium is provided, which is formed by any combination of the above 20 embodiments.

[0260] On the other hand, a gas or liquid filter is provided, which is formed by any combination of the above 20 embodiments.

[0261] In another embodiment, the first embodiment is a filter medium formed by a method comprising the following steps: advancing a fiber-containing substrate from an upstream end to a downstream end; dispersing nanoparticles into the substrate as it is advanced by a feeder to form a filter medium; and conveying nanoparticle clusters from a container to a dispersion device.

[0262] The second embodiment is the first embodiment, and also includes separating the nanoparticle clusters into smaller nanoparticle aggregates.

[0263] The third embodiment is any combination of the first two embodiments, and also includes transporting the nanoparticle clusters from a first height to a second height greater than the first height.

[0264] The fourth embodiment is any combination of the first three embodiments, and also includes vibrating the nanoparticles to separate them from the walls of the collecting vessel.

[0265] The fifth embodiment is any combination of the first four embodiments, and further includes dispersing nanoparticles onto a first surface of the substrate such that the nanoparticles penetrate at least through the first surface of the substrate.

Claims

1. A system for manufacturing filter media, the system comprising: A feeder, used to advance a fiber-containing substrate from the upstream end to the downstream end; A dispersion device for dispersing nanoparticles into the substrate as it is propelled by the feeder to form the filter medium; A container used to receive clusters of nanoparticles; A feeding system for conveying the nanoparticle clusters from the container to the dispersion device.

2. The system of claim 1, wherein the feeding system is configured to deliver the nanoparticle clusters to the dispersing device at a controlled rate.

3. The system of claim 2, wherein the feeding system is configured to deliver the nanoparticle clusters to the dispersion device at a controlled volumetric flow rate.

4. The system of claim 1, wherein the feeding system is configured to separate the nanoparticle clusters into smaller nanoparticle aggregates.

5. The system of claim 1, wherein the feeding system is configured to separate the nanoparticle clusters into individual nanoparticles.

6. The system of claim 1, wherein the feeding system is configured to transport the nanoparticle clusters from the container to the dispersion device at a rate of about 0.05 m / s to about 1.0 m / s.

7. The system of claim 1, wherein the nanoparticles are dispersed in the substrate at a ratio of about 0.1 g / m² to about 10 g / m².

8. The system of claim 1, wherein the container includes a bulk bin for receiving the nanoparticle clusters, wherein the bulk bin includes one or more rotors within the bulk bin for conveying the nanoparticle clusters through the bulk bin.

9. The system of claim 8, wherein the feeding system further comprises a lift for conveying the nanoparticle clusters from a first height in the bulk hopper to a second height greater than the first height.

10. The system of claim 9, wherein the lifter comprises a tube having a plurality of discs disposed within the tube, the discs defining internal compartments within the tube for receiving the nanoparticle clusters.

11. The system of claim 10, further comprising an energy source coupled to the lift for moving the disk from the first height to the second height through the tube.

12. The system of claim 10, wherein the feeding system further comprises a feeding bin coupled to the elevator at the second height.

13. The system of claim 12, wherein the feed hopper includes one or more rotating elements for conveying the nanoparticle clusters through the feed hopper to the dispersion device.

14. The system of claim 13, wherein the one or more rotating elements comprise a helical thruster.

15. The system of claim 1, wherein the feeding system includes one or more vibrating elements for conveying nanoparticle clusters through the feeding system.

16. The system of claim 15, further comprising a collecting vessel disposed between the bulk hopper and the elevator, the collecting vessel including one or more vibrating elements for vibrating the nanoparticles to separate the nanoparticles from the wall of the collecting vessel.

17. The system of claim 1, wherein the dispersing device includes a nozzle configured to disperse the nanoparticles onto a first surface of the substrate such that the nanoparticles at least penetrate through the first surface of the substrate.

18. The system of claim 1, further comprising a fiberizing device disposed between the feeding system and the dispersing device for substantially converting the nanoparticle clusters into individual nanoparticles.

19. The system of claim 18, wherein the individual nanoparticles are spaced apart from each other and at least one dimension has a size of less than 1 micrometer.

20. A filter medium formed by the system of claim 1.

21. A filter formed by the system of claim 1.

22. A system for manufacturing filter media, the system comprising: A container designed to receive multiple nanoparticles at a first height; A lifter, coupled to the container, is used to lift the nanoparticles from a first height in the container to a second height greater than the first height. as well as The device, coupled to the lifter at the second height, includes one or more components for combining the nanoparticles with fibers to form the filter medium.

23. The system of claim 22, wherein the lifter comprises a tube having a plurality of discs configured to move through the tube, wherein each of the discs has an outer diameter smaller than the inner diameter of the tube.

24. The system of claim 23, wherein the disks define compartments between the disks for containing and transporting the nanoparticles.

25. The system of claim 24, wherein the disk is movable within the tube between the first height and the second height.

26. The system of claim 23, wherein the tube includes an opening for receiving the nanoparticles from the container.

27. The system of claim 26, further comprising a dispersion system disposed between the elevator and the device, the dispersion system having an upper opening, wherein the tube has a second opening aligned with the upper opening of the dispersion system for conveying the nanoparticles from the elevator to the dispersion system.

28. The system of claim 25, further comprising a cable coupled to the disk for advancing the disk from the first height to the second height.

29. The system of claim 28, wherein the disk is advanced at an angle transverse to the vertical axis of the container.

30. The system of claim 29, wherein the disk is advanced in a direction substantially perpendicular to the vertical axis.

31. The system of claim 28, further comprising a motor coupled to the cable for propelling the cable through the tube.

32. The system of claim 28, wherein the container includes a bulk bin for containing the nanoparticles and has an opening at a lower end of the bulk bin, wherein the bulk bin includes one or more rotors disposed inside the bulk bin.

33. The system of claim 32, wherein each of the rotors comprises one or more rotating blades for mechanically separating the nanoparticle clusters into smaller nanoparticle aggregates.

34. The system of claim 32, wherein the rotor is configured to rotate about an axis tangential to the height of the container.

35. The system of claim 32, wherein at least some rotors rotate clockwise and at least some rotors rotate counterclockwise.

36. The system of claim 22, wherein the device includes a nozzle for dispersing the nanoparticles onto a first surface of a fiber-containing substrate, such that the nanoparticles penetrate at least through the first surface of the substrate.

37. The system of claim 36, further comprising a fiberization device configured to separate individual nanoparticles from the nanofiber cluster.

38. The system of claim 36, further comprising a lifting belt for advancing the substrate to an adjacency of the nozzle.

39. The system of claim 36, further comprising a coating device for dispersing an adhesive onto fibers in the substrate.

40. The system of claim 36 further includes a dryer disposed near the feeder between the housing and the downstream end of the feeder for heating the nanoparticles and the fibers.

41. The system of claim 37, wherein the individual nanoparticles are spaced apart from each other and at least one dimension has a size of less than 1 micrometer.

42. A filter medium formed by the system of claim 22.

43. A filter formed by the system of claim 22.

44. A filter medium formed by a method comprising the following steps: The fiber-containing substrate is advanced from the upstream end to the downstream end; As the substrate is propelled by the feeder, nanoparticles are dispersed into the substrate to form the filter medium; and The nanoparticle clusters are transported from the container to the dispersion device.

45. The filter medium of claim 44, further comprising separating the nanoparticle clusters into smaller nanoparticle aggregates.

46. ​​The filter medium of claim 44, further comprising transporting the nanoparticle cluster from a first height to a second height greater than the first height.

47. The filter medium of claim 44, further comprising vibrating the nanoparticles to separate the nanoparticles from the wall of the collecting vessel.

48. The filter medium of claim 44, further comprising dispersing the nanoparticles onto a first surface of the substrate such that the nanoparticles at least penetrate through the first surface of the substrate.

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