JP2006524569A - Advanced filtration equipment and filtration method - Google Patents

Abstract

The filter material is composed of a medium for capturing and neutralizing harmful substances. The production method of low pressure, high efficiency filter material to capture harmful substances produces filter material with artificially produced micropores with high performance hole size dispersion, which is monodisperse Or uniform arrangement is possible. The components to be neutralized can be coated on the filter material to improve both the capture efficiency and neutralization of at least one harmful substance among harmful pathogens, aerosols, fine particles, VOCs, gases and vapors.

Description

  The field of this invention is filtration with neutralization and repair of harmful particles, aerosols, vapors and gases, especially in filtration.

  Toxic substances such as toxins and pathogens are present in the air, and if they are in excessive concentrations, they can cause illness. There are many sources of these harmful substances. Some are carried over long distances and others are trapped in indoor environments. Indoor air pollution is a serious concern. For example, toxic mold has become a problem for homeowners and business owners. Furthermore, as in recent incidents, the possibility of using pathogens and toxins as terrorist weapons is also a serious problem. The term toxic substance means natural substances such as dust, mold toxins and pollen, smoke and volatile organic compounds and man-made substances such as terrorist weapons such as VX, sarin, ricin and anthrax . The chemical formulas for the four hazardous substances are shown in FIGS.

  Some toxic chemicals are very reactive polar compounds. For example, the four known chemical weapon categories are asphyxiation agents, erosion agents, blood agents, and nerve agents. Choking agents such as chlorine and phosgene attack the lungs. Erosion agents such as mustard gas (HD) are volatile liquids that cause blisters in organic tissues when absorbed on the skin, in the eye, and inside the lungs. Blood agents such as hydrogen cyanide (HCN) are absorbed into the blood from the lungs or via the intestines (in the case of aqueous HCN) and irreversibly bind to hemoglobin, preventing oxygen uptake. Neural agents such as sarin (GB), soman (GD), and VX are extremely powerful and fatal when inhaled and absorbed through the skin and lungs. Chlorine, phosgene, and hydrogen cyanide are gases. GB, GD, VX, HD are semi-volatile liquids that are generally dispersed as an aerosol or as a mixture of gas and aerosol.

  Research has been done on surface decontamination after exposure to hazardous substances. The dominant decontamination method is absorption (subsequent incineration) and neutralization by chemical reaction. While the structures and functions of these toxic chemicals are very different (FIGS. 1A-1D), all are highly reactive substances and can be quickly neutralized by appropriate combination with reagents. For example, toxic chemicals can react rapidly with oxidants, alkaline solutions, or both. Nerve agents can withstand rapid oxidation to phosphoric acid in the presence of strong oxidants, and HD can withstand oxidation, but are still less toxic but still dangerous. Care must be taken to avoid partial oxidation. Hydrogen cyanide, chlorine, phosgene, HD, sarin, soman, and VX all act rapidly with alkaline solutions, yielding relatively benign products.

  Volatile organic compounds (VOCs) are prevalent throughout residential and commercial buildings and have been shown to cause significant health effects for residents. While national and international health agencies have diverse classifications, VOCs are recognized as compounds that are gaseous or have significant vapor pressure at room temperature. For example, substances such as particleboard, plywood, fabrics, coatings, and insulation release significant amounts of gaseous formaldehyde (which is a common VOC). The peak concentration of formaldehyde in homes and workplaces generally ranges from 0.04 to 0.4 ppm. Regular exposure to peak concentrations above 0.06 ppm can cause significant health effects such as mucous membrane inflammation, rash, severe allergic reactions, fatigue, headache, nausea, depression, and Chronic and prolonged exposure significantly increases the risk of throat cancer. Other VOCs commonly released from residential products include benzene, toluene, styrene acetone, paradichlorobenzene, chloroform, tetrachloroethylene, acrylic esters, and aliphatic ketones and alcohols. In addition, building residents are frequently exposed to volatile sulfur complexes and other low levels of toxic gases such as ammonia gas. Most VOCs can be neutralized by oxidizing agents, alkaline solutions, or both.

  Air filtration systems in air handling systems in buildings, vehicles and personal protective equipment are intended to improve the safety and / or quality of the air we breathe. However, filtration systems such as those used in heating, ventilation, and air conditioning (HVAC) systems do not have the ability to prevent harmful concentrations of bacteria, particles, vapors, and gases from dispersing throughout the structure. See Table I for a comparison of the sizes of some common toxic substances.

車両の空気ろ過システムは、車両付近で有害物質の不測の放出があった場合にそれよりもずっと低いレベルであるが、通常の車両排気ガスを安全なレベルに低減する能力はもたない。有害物質への暴露を防止するようにデザインされた個人用保護装備でさえも、継続的な保護を保証するためにろ過要素の交換が必要となるまでに許容される暴露時間については、厳しい制限がある。

The vehicle air filtration system is at a much lower level when there is an unexpected release of harmful substances in the vicinity of the vehicle, but does not have the ability to reduce normal vehicle exhaust to a safe level. Even personal protective equipment designed to prevent exposure to hazardous substances has strict limits on the exposure time allowed before the filter element must be replaced to ensure continued protection. There is.

  As an example, the concentration of formaldehyde, even from natural and artificial sources, can exceed levels that can be harmful to human health. Few HVAC systems can afford to neutralize these materials. In fact, the HVAC system is more likely to spread intentionally released toxins throughout the building than to provide protection for residents.

  High performance particulate (HEPA) filters may be useful for trapping airborne pathogens and particles. If used, these filters may provide some limited passive defense against some harmful substances such as anthrax.

  HEPA filters are not effective against many other toxic substances, including most volatile organic compounds (VOC) and other toxic substances in the form of vapors, aerosols or gases. HEPA filters are also very efficient at capturing particles, but HEPA filters have additional operational (operating) costs associated with increased resistance to airflow through the HEPA filter. . Although it can be measured as a pressure drop, this resistance to air flow requires more energy to be used for the circulation of air in the filter, which leads to increased operating costs. In addition, the pressure drop across the HEPA filter creates high back pressure, which can lead to leaks in the HVAC conduit, significantly reducing the overall capture efficiency of the system.

  Activated carbon filters used in conventional gas masks are known to provide short-term protection against harmful gases. Activated carbon filters have several limitations that prevent their widespread adoption in HVAC applications such as protective mask filters and reduce their effectiveness in personal protection applications. In particular, the mechanism of gas adsorption on activated carbon is reversible. Thus, absorbed gas can be released by changes in air temperature, humidity, or chemical composition. For example, the presence of a second gas with a high affinity for particulate activated carbon can cause the gas absorbed so far to be released. Furthermore, it can be seen that activated carbon having no polarity has relatively low absorption of polar gas. These limitations mean that a relatively high density of activated carbon necessarily results in reasonable filter life. As stated in connection with HEPA filters, this high density results in a large pressure drop across the filter, which is undesirable for the filtration system. Finally, granular activated carbon that is held loosely in the filter bed is susceptible to the formation of open channels and significantly reduces the effectiveness of the filter. US Pat. No. 6,435,184 is incorporated herein by reference, which discloses, for example, the structure of a conventional protective mask.

  U.S. Pat. No. 3,017,329 issued in 1962 discloses a bactericidal and fungicidal filter using a conventional non-woven filter material. The filter material is coated by a conventional process by applying or dipping the filter material with the active ingredient. The active ingredient is selected from either organic silver compounds or organotin compounds that have a neutral pH but are highly toxic to mammals. The treated filter is then heated to evaporate the water used as a solvent in the coating process and cure the bonding agent that fixes the active ingredient to the filter material.

  U.S. Pat.No. 3,116,969 describes a filter having an alkylaryl quaternary ammonium chloride bactericidal compound, which is retained by an adhesive composition that includes a hygroscopic agent, a thickener and a film former. It is a conventional filter fiber.

  U.S. Pat. No. 3,820,308 describes a sterile filter having a wet oily coating containing a quaternary ammonium salt as a disinfectant.

  M. Dever et al. Tappi Journal 1997, 80 (3), 157 discloses the results of studies on the antibacterial efficacy of antibacterial agents incorporated into fibers in melt blown polypropylene filter media. Three different unidentified drugs were mixed with polypropylin and then meltblown in a conventional manner to form a filter material. Only two of the drugs were detectable by FTIR after treatment, and the two drugs gave antibacterial properties. However, the drug has a negative effect on the physical properties of polypropylene, resulting in a thicker filter material fiber and a lower recovery efficiency than unmixed polypropylene.

  K. K. Foard and J.T. Hanley, ASHRAE Trans., 2001, v.107, p.156 disclose the results of field tests using filters treated with one of three unidentified antimicrobial agents. Known antibacterial filter treatments were not very effective under the test conditions, and both the same growths were seen whether untreated or treated.

  According to A. Kanazawa et al., J. Applied Polymer Sci., 1994, v.54, p.1305, an antibacterial filter material using an antibacterial phosphonium chloride moiety covalently immobilized on a cellulose substrate. Is disclosed. Phosphonium salts with long alkyl chains tended to have a high capacity for bacterial capture.

  M. Okamoto, Proceedings of the Institute of Environmental Sciences and Technology, 1998, p.122 discloses the use of silver zeolite as an antibacterial agent in air treatment filters. Silver zeolite was attached to one side of the filter with a binder.

  US Patent Publication 2001/0045398 discloses a process for the preparation of a non-woven porous material having particles immobilized in the interstices. The particles are added by bringing the material into contact with a suspension of particles, pressing the suspension against the material, trapping entrained particles in the gaps in the porous material, and providing an antimicrobial barrier.

  The English version abstract of WO 00/64264 discloses a bactericidal organic polymer material for a filter made of a polymer base composed of a backbone and a polymeric material pendant group bonded to the backbone. The material is composed of units derived from N-alkyl-N-vinylalkylamide or triiodide ions immobilized on a polymeric material.

  International Publication No. WO 02/058812 discloses a filter material composed of sustained release microcapsules of an antibacterial agent. A microcapsule contains a drug suspended in a viscous solvent that gradually diffuses from the porous shell of the microcapsule. The microcapsules can be held in a conventional filter medium using gum arabic as an adhesive.

  Other methods for removing airborne pathogens include air permeation into a liquid electrostatic precipitator (eg, US Pat. No. 5,993,738), ultraviolet light (eg, US Pat. No. 5,523,075), and any of these methods. Even use much more energy than is acceptable in high dose HVAC applications.

  All of the previous examples have the disadvantages that have not led to widespread adoption in air filtering systems, such as hazardous waste disposal problems, high operating costs, and high costs for manufacturing and maintaining filtration systems. is there. Thus, there is an urgent need to substantially improve the low cost and effective filter protection capabilities. Low energy consumption is particularly needed in the capture and neutralization of harmful particles, pathogen aerosols, vapors and gases.

  Generation of submicron patterns can be achieved using a photolithographic process. This is known in the art of semiconductor device manufacturing, such as the process disclosed by US Pat. No. 5,110,697, which is incorporated herein by reference. Generation of 1-50 micron patterns is easily accomplished by well known conventional processes using photolithography and other conventional techniques such as color printing and embossed sheet printing. In color printing, the registration process for accurate positioning of multiple layers is well known. Also known is embossed sheet production provided with a durable patterned roller surface for processing melted viscous fluids or softened solids. For example, in forming an embossed sheet, polymer melting known as the nip of a calendar roll set with features embedded in the surface is pushed into a narrow gap. These processes are independent of the production of conventional filter media, but are referred to herein as conventional substrate printing.

  The filter is composed of a medium for capturing and neutralizing harmful substances. A high efficiency prefilter at low pressure can be used to capture particles before they enter the filter media. Advanced filter materials are composed of a filtration component and a neutralization component. The neutralizing component is a film of a viscous organic component and a reactive component in which a thin film film is coated on a substrate, and provides a low pressure drop and a highly productive repair of harmful substances.

  In one embodiment, the neutralizing component is retained by a filtering component such as fiber, which retains the neutralizing component. The fibers are dispersed within the filter, ensuring that the air passing through the filter passes through the serpentine channels around the fibers. In this way, harmful substances mixed in the air come into contact with the neutralizing component, thereby neutralizing one or more harmful substances.

  In one embodiment, the filter is comprised of a filtration component and a neutralization component. The filtration component is composed of a plurality of distinguishable layers of filter media or continuously. Regardless, the neutralizing component can be a single activator, a combination of activators, or multiple activators can be linearized into separate regions of the filter component.

  For example, the neutralizing component is retained by the filtration component as shown in FIG. 2, which serves as a substrate for the neutralizing component. In the conventional filter media, as shown in FIG. 7, entangled fibers and entangled fibers were randomly used, but this caused air to pass through the filter and pass through the meandering air passage between the fibers. It was. The fibers are distributed within the filter so that the air passing through the filter must pass through the serpentine channels around the fibers. In this way, harmful substances mixed in the air come into contact with the neutralizing component, thereby neutralizing one or more harmful substances.

  In one example, the filter for neutralizing harmful substances is composed of conventional non-reactive filter materials such as polymer fibers, coatings with a repair layer, and the like. The repair layer is composed of a main component that incorporates one or more neutralizing substances, such as acidic, basic or oxidizing substances. This main component can also have a viscous surface, contaminating particles that collide with the viscous surface can stick to it, increasing the efficiency of particle capture and extending the time of neutralization reaction of particles such as pathogens .

  It has been found that coating a fibrous filter with a thin layer of viscous organic components in the restoration layer absorbs organic gases and aerosols. Highly productive filter media has a reactive coating designed to efficiently capture and neutralize toxic or harmful substances such as pathogens, VOCs and other chemicals. The reactive coating is composed of a reactive component for neutralizing a toxic or harmful substance and a coating substrate in which an adhesive property is provided between the reactive component for the filter material.

  Examples of reactive components include oxidizing agents such as sodium hypochlorite, calcium hypochlorite, and potassium permanganate, acidic complexes such as acrylic acid derivatives and sulfonic acid derivatives, and sodium alkoxides, There are tertiary amines and base complexes such as protective masks as well as compatible mixtures thereof.

  The substrate components are generally poly (vinyl pyrrolidone), poly (vinyl pyridine), poly (acrylic acid) (free acid or salt), poly (styrene sulfonic acid) (free acid or salt), poly (ethylene glycol), poly In addition to polymer materials such as (vinyl alcohol), polysiloxane, polyacrylate derivatives, and carboxymethyl cellulose, there are mixtures and crosslinking agents. In some cases, such as poly (styrene sulfonic acid), the substrate component may also serve as a reactive component. In addition, the substrate component can be composed of a non-volatile complex having a low molecular weight, such as glycerol or ethylene glycol oligomer, to promote target toxicity or affinity for harmful substances.

  The polymer component can also be cross-linked to prevent removal of the reactive coating from the filter fibers under extreme conditions. The reactive coating technique can be applied to any fibrous filter material containing glass and synthetic polymer fibers, such as polyester and cellulose derivatives.

  One advantage of these very efficient filters is the high probability of remediation of toxic or harmful substances. This is a function of the filter structure, and it is desirable that multiple collisions occur between the toxic or harmful substances and the filter material, and the probability of each collision with the filter material leads to an absorption or neutralization reaction. There is no set of conditions that can be universally applied to any substance. Thus, for multiphase filtration, for example, as shown in FIG. 3, a broad spectrum filter with multiple environments is desirable.

The following examples of neutralizing ingredients each provide protection against the specific hazardous substances reported, but may also neutralize other hazardous substances not tested. Example 1
The composition of the resulting aqueous solution of the oxidized gel coating is 20 wt.% Tetraethoxysilane, 20 wt.% Bis (triethoxysilyl) methane, 10 wt.% Glycerol, and 0.05 wt.% Citric acid. A fiberglass pad was immersed in the above solution, dried with blotting paper, and cured by steam heating for 6 hours. The pad was then dipped in an aqueous solution consisting of 2% sodium hypochlorite and 0.5% cyanuric acid and then dried. The resulting filter was effective for the neutralization reaction of diethyl sulfide. Example 2
The resulting aqueous solution of the oxide coating consists of 10 wt% poly (vinyl pyrrolidone). The fiber glass pad was immersed in the above solution, dried with blotting paper, and irradiated for 6 hours under an ultraviolet lamp to cause a crosslinking reaction of the polymer. The pad was then immersed in an aqueous solution consisting of 2 wt% calcium hypochlorite and allowed to air dry. The resulting filter was effective in the neutralization reaction of formaldehyde. Example 3
The composition of the resulting aqueous solution of the oxidation coating is 10 wt% poly (vinyl pyrrolidone) and 2 wt% potassium permanganate. The fiberglass pad was immersed in the above solution and allowed to air dry. The resulting filter was effective in the neutralization reaction of formaldehyde.

Example 4
The resulting aqueous solution of the oxide coating consists of 10 wt% poly (vinyl pyrrolidone). The fiber glass pad was immersed in the above solution, dried with blotting paper, and irradiated for 6 hours under an ultraviolet lamp to cause a crosslinking reaction of the polymer. The pad was then soaked in an aqueous solution of 2% potassium pernanganate and allowed to air dry. The resulting filter was effective in the neutralization reaction of formaldehyde.

Example 5
The composition of the resulting aqueous solution of the oxide coating is 10 wt% poly (ethylene glycol) and 2 wt% calcium hypochlorite. A fiberglass pad was immersed in the above solution and allowed to air dry. The resulting filter was effective in the neutralization reaction of formaldehyde.

Example 6
The composition of the resulting aqueous solution of the oxide coating is 10 wt% poly (acrylic acid) sodium salt and 2 wt% calcium hypochlorite. A fiberglass pad was immersed in the above solution and allowed to air dry. The resulting filter was effective in the neutralization reaction of formaldehyde.

Example 7
The aqueous solution for forming the alkaline coating contains 30 wt% glycerol, 5 wt% polyethyleneimine and 0.25 wt% glycerol propoxylate triglycyl ether. A glass pad was immersed in the solution, dried with blotting paper, and cured at 100 ° C. for 6 hours. Next, the glass pad was immersed in an aqueous sodium hydroxide solution having a pH of 12 or more containing 30 wt% glycerol, removed from the solution, dried with blotting paper, and dried at 50 ° C. for 2 hours. The resulting filter was effective in neutralizing hydrogen cyanide gas.

Example 8
Generation of acidic coating
An aqueous solution is composed of 30 wt% glycerol, 5 wt% styrene sulfonic acid, 0.1 wt% divinyl benzel, 0.13 wt% 2,2'-azobisisobutyronitrile, 0.02 wt% potassium persulfate. Sulfate, and 0.5 wt% sodium dodecyl sulfate. A fiberglass pad was immersed in the above solution, dried with the pad, and then cured at 85 ° C. for 2 hours. The resulting filter was effective for the neutralization reaction of ammonia gas.

Method for Rapid Production of Sheet Filter Material FIG. 10 illustrates a partially enlarged view of a sheet filter material having a uniform rectangular monodisperse hole mesh. Monodispersed means that the hole sizes are substantially the same at least in a significant portion of the sheet filter material. More generally, a filter material having a desired distribution of fine pores can also be produced by this method. For example, FIG. 8 shows another filter material having a honeycomb structure, but any structure can be formed according to the rapid manufacturing method of the sheet filter material.

  One method for producing a filter with fine pores distributed using the technology enables rapid production of a sheet filter material by direct molding and imprinting. Conventional substrate printing methods are used to form two-dimensional or three-dimensional porous sheet filter materials. “Direct molding and imprinting” means that the fibers of the two-dimensional or three-dimensional filter media are formed in situ from the precursor material during the production of the desired filter media structure. The process is distinguished from conventional embossing and papermaking, for example, by forming submicron and larger porous structures by in situ fiber pattern generation. The resulting filter material structure is a pattern of fibers organized and interconnected. The interconnected fiber pattern can also be re-molded into a sheet filter material, providing both strength and flexibility not available with conventional filter materials.

  Occurrence of spontaneous separation of a solution or emulsion consisting of two phases, for example a polymer precursor and a solvent, on a substrate with one surface-tensioned wrinkle part and another surface-tensioned groove part, This is thought to be due to surface tension. Thus, the pattern of fibrous filter material can be laid out by this separation on a printed circuit board, which is a process similar to photolithographic printing, color printing or conventional substrate printing methods such as embossed sheet printing. Patterned using.

  For example, a water-soluble precursor emulsion is prepared for use with a printed circuit board having a ridge and groove pattern on its surface prepared with a photographic plate. The emulsion is prepared such that at least one precursor phase surrounds the ridge and water fills the groove. Alternatively, the orientation of the precursor phase and other solvent containing water phase or precursor phase is reversed by controlling the nature of the water-in-oil or oil-in-water in a multi-phase emulsion or dissolution. You can also The precursor phase can include materials that form fibers by polymerization, solidification, crystallization, catalytic growth from steam, or some other curing process, where there are wrinkles and grooves on the surface of the printed circuit board. The orientation given by the pattern is retained.

  For example, the precursor phase is composed of a polymer precursor that forms polymer fibers in situ during phase separation on the surface of the substrate surface. The removal of the aqueous phase or solvent is then accomplished, for example, by evaporation, leaving well-defined voids of a particular size, shape and distribution between the polymer strands, which are interconnected in a wrinkle pattern Is done. An interconnected fiber network is formed. Fibers with defined micropores in the filter material can be coated by neutralizing the components to help capture and neutralize harmful substances. In one example, the fiber is heavily coated by component neutralization, which is provided for efficient particle capture and neutralization of appropriate noxious gases such as volatile organic compounds (VOCs). .

  In another example, the precursor phase is a cellulosic polymer or proteolytic polymer dissolved or digested in an aqueous solution, which is mixed with the solvent in the emulsion, which is in the ridges on the printed circuit board surface. To separate. In this example, the precursor phase is formed in situ in the groove. The resulting fiber retains the groove pattern and can be any pattern. For example, the pattern may be a mesh, a honeycomb, or other two-dimensional geometric figure.

  In one embodiment, the separation of the precursor phase from the aqueous or solvent phase is not due to material differences in the ridges or grooves on the surface of the printed circuit board. Rather, this separation occurs due to the temperature difference between the material inside the ridge and the groove, which promotes spontaneous precursor phase assembly. In this particular example, the precursor supply need not even be a multiphase system. For example, the prepolymer or polymer can be selected to form from a metastable solution around a relatively cool shape, leaving a solvent-rich and stable solution at a relatively warm spot. Thus, the sheet filter material can also be formed from a water-insoluble polymer solution.

  As another method, there are no ridges or grooves on the surface of the printed circuit board. Instead, the surface is substantially flat and is composed of patterns of different materials such as patterns printed on the surface of the printed circuit board. Different materials have different surface tensions with the emulsion or dissolution, which causes separation of the precursor phase from the aqueous or solvent phase. As described above, the fiber pattern can also be formed from the printed circuit board.

  In yet another example, the precursor phase was dissolved in an acrylated monomer / crosslinker / photoinitiator such as polyethylene terephthalate plasticized with a mixture of benzyladenine and bisphenol-A-diacrylate. Composed of polyester. The roller surface is patterned by conventional substrate printing methods, and the roller is used so that phase transition and self-assembly are initiated spontaneously according to the pattern on the roller surface. A patterned sheet is formed, which is exposed to a strong UV source, thereby causing the acrylate formulation to undergo a polymerization reaction and to form a molecular network that penetrates each other within the polyester fibers. If any residual water or other solvent is evaporated, the organic fibers remain in the sheet filter material, which is strongly cross-linked and flexible.

  The polyester fibers are firmly fixed by the interpenetrating acrylic network, thereby ensuring the stability and durability of the porous pattern formed by the rollers. In this way, the sheet filter material has a pattern of fine pores having a certain size, distribution, and spacing based only on the pattern supplied to the roller surface and the thickness of the organic polymer strand. The roller pattern can have any pattern from sub-micron sizes to 50 microns, depending on the filtering application. The thickness of the strands can be controlled by the amount of precursor components and the concentration of precursor components in the diluent or solvent.

  In another example, a partially polymerized fluorocarbon (fluorocarbon) suspension in water is contacted with the surface of a roller having an embossed pattern of poly (tetrafluoroethylene). The fluorocarbon material accumulates around the poly (tetrafluoroethylene) pattern, leaving water (or an aqueous solution) in the metal oxide area on the roller surface. The patterned fluorocarbon is polymerized by a polymerization reaction by applying heat or light (such as ultraviolet light). This process produces a very dense lace-like fluorocarbon filter material.

  Alternatively, a polyester or nylon sheet is formed by the same process, but with a partially polymerized precursor (or a mixture of non-active polymers and even unreacted or partially reacted precursors, etc. Other precursors) differ in that they are used to form polyester or nylon. A lace-like filter material can also be formed from polyester and nylon sheets. After the lace-like structure is formed and the polymerization is complete, the sheet filter material is mechanically extended in both vertical directions simultaneously. This stretching causes the fibers to be pulled uniformly, reducing the fiber diameter and increasing the micropore size. This technique can be applied to other precursors as well, but this enables the production of filter materials with submicron fiber diameters, and capture efficiency and pressure compared to larger diameter fibers. Problems between the nature of the descent are improved.

  In yet another embodiment, fibers before spinning in a complex process are used with direct molding and imprinting to form a filter material. For example, unspun parallel fibers can be fed into a calendar with embossed lines perpendicular to the direction of parallel fiber travel. The feed containing the precursor contacts the embossed surface and forms a pattern of precursor material on the parallel fibers. The precursor reacts to form a sheet filter material in combination with the fibers before spinning. In one example, there is a wide gap between “warp” and “weft”. That is, the fiber formed in situ and the fiber before spinning. The new fibers adhere to the fibers before spinning and give strength to the hybrid filter material. Furthermore, the fibers can be swirled by the overlapping concentration points, and sufficient flexibility is given depending on the material. As above, the new fibers can be porous or non-porous, synthetic or natural, simple and composite structures. The new fiber has a core-shell geometry because it uses an organic water-soluble system with at least two phases, both of which contain a polymer or precursor. The fiber pattern also includes wavy lines, curved lines, or articulated lines deposited on the unspun fibers, which use traditional unspun fibers without casting and imprinting. It is impossible.

  In yet another embodiment, a water-soluble-organic-water soluble composite emulsion can be used in the design of the porous yarn. These porous yarns surround the voids, but also have voids inside the strands, which are formed when the water formed inside the strands evaporates due to, for example, chemical affinity with water or surface tension. is there. As an example, the production of such porous polymer strands uses hydrophilic and hydrophobic moieties.

  The pattern can also be generated using the process of the present invention, which is difficult or impossible to reproduce using other methods with low cost, high volume production filter media. For example, the sheet filter material is manufactured with at least one region of monodisperse hole size. Furthermore, the size, shape and distribution of the monodispersed holes are preferably uniform over the large surface area of the sheet filter material. Uniform hole size has the ability to greatly improve the efficiency of particle capture of the filter material per amount of fiber compared to conventional non-uniform filter material. Thus, compared to conventional filter materials, the sheet filter material of the present invention has a lower pressure drop for the desired particle capture efficiency or a higher particle capture efficiency for the desired pressure drop. .

  In another example, a sheet filter material can be formed in a two-phase or multi-phase system using a mixture of many polymers with hydrophilic and hydrophobic properties. Polymer blends include amorphous or crystalline polymers, homopolymers or crosslinkers, inactive polymers mixed with reactive components (monomers, oligomers, crosslinkers, etc.), and viscous reactive oligomers and macromers. Can be mixed. For example, the reaction for forming the fiber network can be free radical or of condensation nature. The polymer and polymer precursor may be either synthetic or natural. Synthetic polymers can spin not only hydrocarbons such as polyolefin polyesters, acetates, acrylics and nylons, but also fluorocarbons and silicones.

  When employing mechanical means to form a thin porous sheet filter material, the interfacial properties between the polymer / precursor system and the roller can be exploited to create a wool-like structure. If there is strong but temporary adhesion between the feed material and the forming substrate surface, thin threads and whiskers can be pulled out of the filter sheet. Many yarns and whiskers can thus be made like wool until the viscoelasticity of the material breaks the thin string between the substrate surface and the supply substance. In one example, the tufts can then be cured to produce a three-dimensional structure like this wool. In addition, a very fine sheet filter material can be manufactured by promoting thread formation with a large number of nanoscale or microscopic wrinkled substrate surfaces deliberately worn (ie, roughened). Alternatively, a regular and clean sheet filter material is ensured by creating a wrinkle-free surface and using a release agent to reduce the surface tension between the substrate surface and the feed material. .

  In another example, two rollers in a pair have parallel grooves. One set is across the width of the first roller and the second set is in the periphery of the second roller. As the feed material containing the precursor components is pushed into the nip, a crossed fibrous pattern is generated. In one example, the line is not continuous across the width of the first roller and the periphery of the second roller. Thus, a highly flexible pattern is formed. In addition, the roller surface can be provided with points in the intended groove, resulting in a sheet filter material with raised points and improved tactile properties.

  In another embodiment, a sacrificial layer or carrier film such as a soluble film is used. The pattern can be applied to either the sacrificial layer or the carrier film on one or both sides by any of the methods of the present invention. For example, these patterns may be multi-layered, or “bias” methods formed by the sacrificial layer, such as by forming an existing hole in the pattern on the opposite side of the sacrificial layer, A connection may be formed. After the sheet filter material is formed, the sacrificial layer can be melted to provide an interconnection only between the sheet filter materials at specific interconnection points corresponding to the location of the bias. Thus, complex three-dimensional geometries are formed, which is not possible using conventional filter media. Alternatively, the carrier film can be simply peeled away from the filter material and reused, possibly reducing manufacturing costs.

  In another embodiment, a semi-solid film containing at least one precursor is embossed and pressed against a set of rollers with a pattern thereby on the surface of each other. For example, patterns such as lines and holes can be drilled in a semi-solid film to create an opening that can be improved by carefully stretching the semi-solid film. Next, the precursor of the semi-solid film is subjected to treatment such as polymerization, vulcanization, crystallization or solidification to produce a complete solid sheet filter material, with the openings remaining retained. For example, in addition to heating, a semi-solid film may be irradiated with ultraviolet light, X-rays, microwaves, electron beams, or gamma rays to completely react the semi-solid film to form a solid sheet filter material. it can.

The term “semi-solid film” refers to yielding in a state of high shearing force while exhibiting film properties in a state of no shearing force or a state of low shearing force. Thus, the semi-solid film can be handled as a solid film, but can be easily perforated by the raised surface of the roller. In one example, the semi-solid film has a modulus of 10 ⁶ dynes / cm ² to 10 ⁷ dynes / cm ² . In another example, the roller can apply a relatively large force, increasing the upper modulus limit to a value not exceeding 10 ¹⁰ dynes / cm ² . For example, the elastic modulus of a semi-solid film can be modified by mixing diluents, plasticized polymers and partially increased (by solvent) polymers by mixing high and low molecular weight polymers. . One or more of these components may be reactive with other materials, such as non-active polymers with pendant functional groups (which may be cross-linked by cross-linking components or drugs) . In addition, the diluent or plasticizer can completely or partially undergo either a polymerization reaction or a crosslinking reaction to form a polymer network (IPN) that penetrates each other. Semi-solid films are also reactive oligomers or macromers or mixtures, as well as antioxidants, flame retardants, mold release agents, flow aids, bioactive agents, activated carbon, microfibrils, other additives, existing natural and synthetic It can be composed of fibers.

  In another embodiment, the semi-solid film need not be mechanically perforated by a roller. Instead, the membrane can be solidified by depositing it on one or both surfaces of a semi-solid film in an opaque area and irradiating it with ultraviolet light, etc., before processing the membrane precursor. Next, the non-solidified opaque region can be preferentially melted to make a hole in the sheet filter material. As with standard photographic plates, a mask can be used to obtain opaque areas. The mask can be prepared by covering a patterned metal with a mylar film. The patterned mylar film then creates shadows on the semi-solid film while irradiating the semi-solid film with radiation. For example, while moving on a conveyor, the radiation source can solidify the unsolidified portion of the semi-solid film. Alternatively, rapid laser scanning is another method for generating a pattern in a semi-solid film.

  In another example, the semi-solid film may be developed independently, or the semi-solid film may be one or more layers of a multilayer filter media. For example, the multilayer film can be irradiated on the opposite side simultaneously or sequentially. If one of the layers is a semi-solid film, the other layers can be deposited thereon as with any substrate. For example, the central semi-solid film can be formed in fewer steps than necessary to form each layer independently, with one or both sides covered with a liquid precursor to form a laminated open filter structure. . In one embodiment, the hole size is larger on one side of the multilayer than the other. Thus, the size of the hole in the layer on the first surface of the multilayer filter is the largest and the layer on the opposite surface is the smallest. The size of the hole in the middle layer varies from maximum to minimum in order from the first surface to the opposite surface, which is a progressive mini-sieve that can filter the largest particles first. Can be used. In such a multilayer filter, there are cases where there are micropores that are substantially aligned, and cases where there are micropores that are displaced from the next layer in order to improve the meandering property of the air flow path. The path meandering may increase particle capture efficiency, but also increases the pressure drop across the filter. The determination of the optimal sequence for a particular application is within the ordinary skill in the art.

  In another method, inkjet printing is used to deposit a pattern of fibrous precursor on a surface, such as a flat or curved surface. In one embodiment, multiple nozzles are employed simultaneously to rapidly deposit the precursor component on the surface. Any conceivable pattern can be printed in this way, and different precursors can be deposited with different nozzles, both reactive and non-reactive. Furthermore, in this method, the precursor can be cured by the use of heat, light or the addition of a catalyst, and the precursor can be fused, polymerized, and further polymerized during or after ink jet printing. In one embodiment, the surface is a non-stick surface and the cured sheet filter material can be removed by simply peeling the sheet filter material from the surface. For example, a Teflon surface, ie, a substrate covered with polytetrafluoroethylene (PTFE) or a non-stick coating can be used.

  In another embodiment, the nozzle vibrates or moves in a predetermined pattern, causing the fibrous material to be continuously ejected from the nozzle, depositing the pattern on the surface. For example, in a pattern, the strands can be fused together by letting one strand cross over another strand. Alternatively, the strand can deposit the line and then rotate the table under the strand, so that on the second pass, the second line pattern intersects the first line pattern. Can be. The strands can then be fused using heat or in some way, such as a crosslinking reaction by photopolymerization. Alternatively, the process can be a continuous process using a conveyor belt to move the deposition surface from one set of nozzles to the next. Different precursor materials can be deposited in several layers (non-adjacent layers) with different nozzles and merged together. As an example, the connection points crossing the cross, together with some connected points and other unconnected points, a three-dimensional structure is formed by extending a two-dimensional sheet filter in three dimensions. . By using this method to selectively fuse certain points between alternating layers of filter material with multiple layers deposited by a nozzle, very complex two- and three-dimensional patterns are formed. The

  In another method, laser printing techniques are used to deposit the precursor on the surface, followed by polymerization. The precursor is deposited using a plate or roller, imparts static electricity to the toner, forms a pattern, and then moves to the moving surface. The toner putter can include a precursor and can be used to form the precursor into a previously related pattern.

  In yet another embodiment, the feed material can include a swelling or blowing agent. Any conventional swelling or blowing agent can be incorporated into the fiber situation. Once the lace-like structure is formed, the fibrous strands are stretched to produce hollow fibers, porous fibers, or a combination of the two.

  The method and advanced filter material presented in this document have a specific hole size, shape and distribution, reduce pressure drop and improve capture efficiency compared to traditional filters with randomly oriented fibers High-performance microfilters and submicron filters can be produced. Also, a conventional filter with a random fiber distribution requires more material to achieve the same level of filtering and increases the filter cost.

  One or more of these filter media can also be coated with a neutralizing component and can neutralize one or more harmful substances such as harmful particulates, aerosols, gases, vapors and pathogens.

  The advanced filter of the present invention can be used in a variety of filtration systems including HVAC, surgical masks, protective masks, vacuum cleaner dust bags, sieves, isolation, clean rooms, transportation and industrial applications.

  It is impossible to list all combinations that can be used to form a sheet filter material. Although the invention has been described with reference to particular embodiments and examples thereof, many other variations and modifications and other uses will be apparent to those skilled in the art. They are intended to be included within the scope of the claimed invention. Thus, the present invention is not limited to the specific disclosures contained herein, but is preferably according to the issued claims.

Indicates the chemical formula of the hazardous substance. Indicates the chemical formula of the hazardous substance. Indicates the chemical formula of the hazardous substance. Indicates the chemical formula of the hazardous substance. Fig. 1 illustrates an embodiment of the invention having fibers coated with a repair layer. Illustrates one embodiment of a broad spectrum filter for the repair of a number of toxic or harmful substances. Indicates a filter fiber without a repair layer. Shows a fiber coated with a repair layer, put in an incubator at a temperature and humidity suitable for mold growth, and then applied with a solution containing mold spores. FIG. 5 illustrates the fiber of FIG. 4 coated and cultured in the same manner as in FIG. 5, with significant mold growth compared to the embodiment illustrated in FIG. Shows the actual fiber of the filter according to the prior art. Fig. 2 illustrates a filter composed of a coarse prefilter, a neutralizing component that coats the coarse prefilter, and a sheet filter material. Fig. 2 illustrates the concept of fiber wrapping. It means that a layer of functional polymer is placed on the surface of the fiber to provide a repair layer. Fig. 4 illustrates an embodiment of a sheet filter material. These show the preparation method of a sheet filter material. These show the preparation method of a sheet filter material. These show the preparation method of a sheet filter material.

Claims (20)

Filter material for filtering harmful substances, consisting of:
Interconnected fiber mesh.
A network of interconnected fibers defines a micropore with a size distribution of artificial pores rather than random, where the micropore size does not exceed 50 microns.   2. The filter material according to claim 1, wherein the fine pore size distribution is monodisperse.   2. The filter material according to claim 1, wherein a honeycomb-shaped micropore pattern is defined by a network of fibers connected to each other.   2. The filter material according to claim 1, wherein a rectangular fine pore pattern is defined by a network of fibers connected to each other. Filter material for filtering harmful substances, consisting of:
Interconnected fibers.
A neutralizing component that covers at least one portion of a network of interconnected fibers.   6. The filter media of claim 5, wherein the interconnected fiber network is covered with a substantially neutralizing component. 6. The filter material according to claim 5, wherein the components to be neutralized are composed of the following.
The main component.
One or more neutralizing substances.   8. The filter of claim 7, wherein the one or more neutralizing substances are selected from the group consisting of acidic substances, basic substances and oxidizing substances.   8. The filter of claim 7, wherein the main component has a viscous surface.   8. A filter according to claim 7, wherein the main component is a thin layer of viscous organic components.   8. The filter of claim 7, wherein the one or more neutralizing components comprise at least one oxidant.   12. The filter of claim 11, wherein the oxidant is selected from the group consisting of sodium hypochlorite, calcium hypochlorite, potassium permanganate and mixtures thereof.   8. The filter of claim 7, wherein the one or more neutralizing components are selected from the group of acidic complexes consisting of acrylic acid derivatives, sulfonic acid derivatives, and mixtures thereof.   8. The filter of claim 7, wherein the one or more neutralizing components are selected from the group of base complexes consisting of sodium alkoxide, tertiary amine, and pyridine and compatible mixtures thereof.   6. The filter of claim 5, wherein the fibers are poly (vinyl pyrrolidone), poly (vinyl pyridine), poly (acrylic acid) (free acid or salt), poly (styrene sulfonic acid) (free acid or salt), Made of high molecular weight materials such as poly (ethylene glycol), poly (vinyl alcohol), polysiloxane, polyacrylate derivatives, carboxymethyl cellulose, or mixtures or crosslinkers. A method of manufacturing a filter material that consists of the following procedures.
Procedure to prepare precursor emulsion or solution.
Procedure for patterning a substrate. Here, the pattern is formed on the surface of the substrate.
A procedure in which a substrate is brought into contact with a precursor emulsion or solution in which at least one precursor is separated from the emulsion or solution in a pattern applied to the surface of the substrate.
Procedure for reacting precursors. This separates from the emulsion or solution and forms a sheet filter material.
Procedure to remove the sheet filter material from the substrate.   17. The method of claim 16, wherein the patterning procedure comprises the formation of wrinkles and grooves on the surface of the substrate.   18. The method of claim 17, wherein the separation is by temperature difference.   17. The method of claim 16, wherein the substrate surface is substantially flat and the patterning procedure is formed by different materials deposited on the substrate surface.   17. The method of claim 16, wherein the reaction procedure includes a step of polymerizing the precursor by irradiating the precursor with ultraviolet light.

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