Nanofiber filter and manufacturing method therefor

Abstract

Disclosed are a nanofiber filter capable of simultaneously reducing a particulate matter and a gaseous material, and a manufacturing method therefor. The method for manufacturing a nanofiber filter according to a first embodiment of the present invention comprises the steps of: (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying metal-organic framework (MOF) powder onto the support, wherein the step (a) and the step (b) are performed simultaneously to fabricate a nanofiber filter in which nanofibers and MOF powder are coated on the substrate, and in the step (a), the MOF powder is electrostatically sprayed in a coating amount of 11.7g / m2 or more. The method for manufacturing a nanofiber filter according to a second embodiment of the present invention comprises the steps of: (a) electrospinning a solution containing a polymer and an organic solvent onto a support to prepare a nanofiber layer; (b) electrostatically spraying metal-organic framework (MOF) powder on the nanofiber layer to prepare an MOF powder layer; and (c) performing the steps (a) and (b) one or more times to alternately stack the nanofiber layer and the MOF powder layer.

Description

Nanofiber filter and its manufacturing method

[0001] The present invention relates to a nanofiber filter capable of simultaneously reducing particulate matter and gaseous matter, and a method for manufacturing the same.

[0002] Particulate matter (PM) or toxic gas is a substance that contains numerous air pollutants, including sulfur dioxide, nitrogen oxides, lead, ozone, and carbon monoxide. It refers to fine dust generated from automobiles, factories, etc., and lingers in the air for long periods of time.

[0003] Most products designed to improve indoor air quality, such as air purifiers, car air filters, and air conditioners, incorporate filters. These filters are composed of bundles of fibers that filter out microscopic particles such as fine dust, bacteria, and viruses floating in the air.

[0004] Filters are broadly classified into two types: non-woven filters made of polypropylene and HEPA filters made of glass fiber. Polypropylene non-woven filters can remove fine dust (PM 2.5) particles smaller than 2.5㎛ in diameter, but struggle to remove ultrafine dust particles smaller than 0.3㎛. HEPA filters come in various grades, but generally, those that remove at least 99.97% of particulate matter 0.3㎛ in diameter are certified as HEPA.

[0005] As a method for manufacturing a filter, for example, a PTFE nanofiber layer is formed on the surface of a fibrous filter using electrospinning, and PTFE powder is sprayed using electrostatic spraying to artificially increase the content of fluorine (F) and improve the roughness of the filter itself, thereby manufacturing a filter. However, the PTFE powder is the same material as the nanofiber layer, not an adsorbent material, and can only remove particulate matter, which is a limitation of fibrous filters.

[0006] To address these issues, methods have recently been used to electrostatically spray adsorbents, such as metal-organic framework (MOF) powders, onto the surface of fibrous filters to enhance functionality. However, this method of surface coating has the disadvantage of making it difficult to effectively remove gaseous substances, as the coating is applied in small quantities rather than in large quantities to prevent increased pressure loss.

[0007] Therefore, a method for manufacturing a nanofiber filter capable of simultaneously reducing particulate matter and gaseous matter without increasing pressure loss is needed.

[0008] An object of the present invention is to provide a nanofiber filter capable of simultaneously reducing particulate matter and gaseous matter without increasing pressure loss.

[0009] In addition, it is an object of the present invention to provide a method for manufacturing a nanofiber filter capable of coating a large amount of adsorbent compared to conventional methods using electrospinning and electrostatic spraying.

[0010] The objectives of the present invention are not limited to those mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0011] A method for manufacturing a nanofiber filter according to a first embodiment of the present invention is characterized by comprising the steps of (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying MOF (metal-organic framework) powder onto the support.

[0012] A method for manufacturing a nanofiber filter according to another first embodiment of the present invention comprises the steps of (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying MOF (metal-organic framework) powder onto the support; and by performing steps (a) and (b) simultaneously, a nanofiber filter coated with nanofibers and MOF powder on the support is manufactured, and in step (a), the MOF powder is added at 11.7 g / m. 2 It is characterized by electrostatic spraying with the above coating amount.

[0013] A method for manufacturing a nanofiber filter according to another first embodiment of the present invention comprises the steps of (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying MOF (metal-organic framework) powder onto the support; characterized in that steps (a) and (b) are performed simultaneously to manufacture a nanofiber filter in which nanofibers and MOF powder are coated on the support.

[0014] A method for manufacturing a nanofiber filter according to another first embodiment of the present invention comprises the steps of (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying MOF (metal-organic framework) powder onto the support; wherein, in step (a), the MOF powder is sprayed at 11.7 g / m 2 It is characterized by electrostatic spraying with the above coating amount.

[0015] A method for manufacturing a nanofiber filter according to another first embodiment of the present invention comprises the steps of (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying MOF (metal-organic framework) powder onto the support; wherein the average diameter of the MOF powder is more than 0.3 µm and less than or equal to 10 µm.

[0016] According to another first embodiment of the present invention, a method for manufacturing a nanofiber filter comprises the steps of (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying MOF (metal-organic framework) powder onto the support; wherein steps (a) and (b) are performed simultaneously to manufacture a nanofiber filter in which nanofibers and MOF powder are coated on the support, and the average diameter of the MOF powder is more than 0.3 µm and less than 10 µm.

[0017] A method for manufacturing a nanofiber filter according to another first embodiment of the present invention comprises the steps of (a) electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) electrostatically spraying MOF (metal-organic framework) powder onto the support; wherein, in step (a), the MOF powder is sprayed at 11.7 g / m 2 The electrostatic spraying is performed with the above coating amount, and the average diameter of the MOF powder is characterized by being more than 0.3㎛ and less than 10㎛.

[0018]

[0019] A method for manufacturing a nanofiber filter according to a second embodiment of the present invention is characterized by alternately stacking a nanofiber layer and a MOF powder layer.

[0020] A method for manufacturing a nanofiber filter according to another second embodiment of the present invention is characterized in that a nanofiber layer and a MOF powder layer are alternately laminated, and the average diameter of the MOF powder in the MOF powder layer is more than 0.3 ㎛ and less than 10 ㎛.

[0021] A method for manufacturing a nanofiber filter according to another second embodiment of the present invention comprises alternately stacking nanofiber layers and MOF powder layers, and adding MOF powder at 11.7 g / m 2 It is characterized by forming a MOF powder layer by electrostatic spraying with the above coating amount.

[0022] A method for manufacturing a nanofiber filter according to another second embodiment of the present invention is characterized by including: (a) a step of electrospinning a solution containing a polymer and an organic solvent onto a support to manufacture a nanofiber layer; (b) a step of electrostatically spraying MOF (metal-organic framework) powder onto the nanofiber layer to manufacture an MOF powder layer; and (c) a step of alternately stacking a nanofiber layer and an MOF powder layer by performing steps (a) and (b) at least once.

[0023] In the first embodiment or the second embodiment, the average diameter of the MOF powder may be more than 0.3 μm and less than or equal to 10 μm.

[0024] The above electrospinning may include the steps of filling the solution into a syringe, providing a collecting plate so as to be spaced apart from the syringe, and placing a support on the collecting plate; and applying voltage to the syringe, such that nanofibers are discharged from a nozzle of the syringe by the applied voltage, thereby coating the nanofibers on the support.

[0025] In the first embodiment or the second embodiment, the electrostatic spraying may include a step of injecting a solution containing MOF powder into a nozzle and applying voltage to spray MOF powder in the form of droplets onto a support through the nozzle.

[0026] In the second embodiment, in the step (b), the MOF powder is 11.7 g / m 2 Electrostatic spraying is possible with the above coating amount.

[0027] In the first embodiment or the second embodiment, in step (a), the polymer may include at least one of polypropylene (PP), polyurethane (PU), polyether sulfone, polyester (PES), polyimide (PI), polymethyl methacrylate (PMMA), nylon, polystyrene (PS), Teflon (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and polyacrylonitrile (PAN).

[0028] In the first embodiment or the second embodiment, in step (a), the organic solvent may include at least one of dimethylformamide (DMF), diethylformamide (DEF), dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and methylpyrrolidone (NMP).

[0029] In the first embodiment or the second embodiment, the MOF powder is a metal ion and an organic ligand coordinately bonded, and the metal ion includes at least one of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, La, W, Os, Ir, Pt, Au, Hg, Sm, Eu, Gd, Tb, Dy, Ho, Al, Ga, In, Ge, Sn, Pb, Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba, and the organic ligand includes 1,4-benzenedicarboxylic acid (BDCA), isophthalic acid, 1,3,5-benzenetricarboxylic acid (BTCA), 2,5-dihydroxyterephthalic acid, 2-aminoterephthalic acid, 2-nitroterephthalic acid, 2-methylterephthalic acid, 2-haloterephthalic acid, azobenzene tetracarboxylic acid, 1,3,5-tri(4-carboxyphenyl)benzene, 2,6-naphthalene dicarboxylic acid (NDCA), benzene-1,3,5-tribenzoic acid (BTB), fumaric acid, glutaric acid, 2,5-furanedicarboxylic acid;FDCA), 1,4-pyridinedicarboxylic acid, 2-methylimidazole, alkylsubstituted imidazole, aromatic ringsubstituted imidazole, 2,5-pyrazinedicarboxylic acid, 1,4-benzene dipyrazole, 3,5-dimethyl-pyrazolate-4-carboxylate, 4-(3,5-dimethyl-1H-pyrazol-4-yl) benzoate, 1,4- 1,4-(4-bispyrazolyl) benzene, deprotonated 2-methylimidazole, 4,4'-biphenyldicarboxylic acid, 1,3,6,8-tetrakis(p-benzoic acid)pyrene, tetrakis(4-carboxyphenyl)porphyrin, 1,1'-biphenyl-3,3',5,5'-tetracarboxylic acid and N,N,N',N'-tetrakis(4-carboxyphenyl)-biphenyl-4,4'-diamine It may contain one or more of (N,N,N',N'-tetrakis(4-carboxyphenyl)-biphenyl-4,4'-diamine: TCBTDA);

[0030]

[0031] A nanofiber filter according to a first embodiment of the present invention comprises a support; and a coating layer disposed on one surface of the support; wherein the coating layer comprises nanofibers and MOF (metal-organic framework) powder; and the content of the MOF powder is 11.7 g / m 2 It is characterized by the following:

[0032] A nanofiber filter according to another first embodiment of the present invention comprises a support; and a coating layer disposed on one surface of the support; wherein the coating layer comprises nanofibers and MOF (metal-organic framework) powder; and the average diameter of the MOF powder is characterized in that it is more than 0.3 ㎛ and less than 10 ㎛.

[0033]

[0034] A nanofiber filter according to a second embodiment of the present invention comprises: a support; a nanofiber layer disposed on the support; and a MOF (metal-organic framework) powder layer disposed on the nanofiber layer; characterized in that the nanofiber layer and the MOF powder layer are alternately laminated at least once.

[0035] A nanofiber filter according to another second embodiment of the present invention comprises a support; a nanofiber layer disposed on the support; and a MOF (metal-organic framework) powder layer disposed on the nanofiber layer; wherein the content of the MOF powder in the MOF powder layer is 11.7 g / m 2 It is characterized by the following:

[0036] A nanofiber filter according to another second embodiment of the present invention comprises: a support; a nanofiber layer disposed on the support; and a MOF (metal-organic framework) powder layer disposed on the nanofiber layer; wherein the average diameter of the MOF powder is more than 0.3 µm and less than or equal to 10 µm.

[0037] In the second embodiment, the content of MOF powder in the MOF powder layer is 11.7 g / m 2 It could be strange.

[0038] In the first embodiment or the second embodiment, the average diameter of the MOF powder may be more than 0.3 μm and less than or equal to 10 μm.

[0039] According to the present invention, nanofibers and MOF powders can be coated on a support by performing electrospinning and electrostatic spraying simultaneously, or nanofiber layers and MOF powder layers can be alternately laminated by alternately using electrospinning and electrostatic spraying.

[0040] Accordingly, the nanofiber filter manufactured according to the manufacturing method of the present invention has the effect of simultaneously reducing particulate matter and gaseous matter without increasing pressure loss.

[0041] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0042] Figure 1 is a flowchart of a method for manufacturing a nanofiber filter according to a first embodiment of the present invention.

[0043] Figure 2 is a flowchart of a method for manufacturing a nanofiber filter according to a second embodiment of the present invention.

[0044] Figure 3 is a cross-sectional view of a nanofiber filter according to the first embodiment of the present invention.

[0045] Figure 4 is a cross-sectional view of a nanofiber filter according to a second embodiment of the present invention.

[0046] Fig. 5 is a cross-sectional view of a nanofiber filter according to sample 1 of the present invention.

[0047] Figure 6 is a SEM image of a nanofiber filter according to sample 1 of the present invention.

[0048] Fig. 7 is a cross-sectional view of a nanofiber filter according to sample 2 of the present invention.

[0049] Fig. 8 is a SEM image of a nanofiber filter according to sample 2 of the present invention.

[0050] Fig. 9 is a cross-sectional view of a nanofiber filter according to sample 3 of the present invention.

[0051] Fig. 10 is a SEM image of a nanofiber filter according to sample 3 of the present invention.

[0052] [Explanation of symbols]

[0053] 10, 100: Support

[0054] 20: Nanofiber

[0055] 30: MOF powder

[0056] 200: Nanofiber layer

[0057] 300: MOF powder layer

[0058] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0059] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0060] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0061] Hereinafter, a nanofiber filter and a method for manufacturing the same according to some embodiments of the present invention will be described.

[0062] The method for manufacturing the nanofiber filter of the present invention can coat nanofibers and MOF powder on a support by performing electrospinning and electrostatic spraying simultaneously, or can alternately stack nanofiber layers and MOF powder layers by using electrospinning and electrostatic spraying alternately.

[0063] Accordingly, the above manufacturing method has the effect of simultaneously reducing particulate matter and gaseous matter without increasing pressure loss, despite increasing the coating amount of MOF powder, which is an adsorbent, compared to existing filters.

[0064] In the present invention, "spinning" means converting a polymer solution, which has been heated and melted or dissolved in a solvent, into a thin fiber, i.e., a yarn, by continuously passing it through a small-diameter nozzle or other hole. In this case, electrospinning means applying a high direct current voltage of several thousand to tens of thousands of volts to the solution to produce the solution in the form of a yarn.

[0065] In the present invention, "spraying" means forming droplets of a coating solution and spraying them to form a thin film. In this case, electrostatic spraying means applying a high direct current voltage of several thousand to tens of thousands of volts to the solution to break the liquid into small droplets.

[0066] Pressure loss is caused by the flow rate passing through the filter volume. The pressure loss value is calculated as the difference between the upstream and downstream sides of the filter.

[0067] Pressure loss reduction occurs when the average diameter of the nanofibers in the fabric acting as the filtration layer approaches or is smaller than 65 nm. This reduces airflow resistance due to the sliding effect of air molecules. This, in turn, reduces pressure loss. As the number of particles captured by the filter increases, pressure loss increases. In terms of CADR, increased pressure loss significantly impacts performance because it reduces the airflow of the air purifier.

[0068] In the air purifier industry, energy efficiency and the area cleaned are crucial. Using a filter with a high differential pressure significantly reduces the supply of purified air. To compensate, the fan output of the air purifier must be increased. This increases the air purifier's power consumption and may result in noise. If the fan output remains unchanged, the area cleaned by the filtered device will be significantly reduced. This makes it difficult to purify indoor air quality.

[0069] In the present invention, particulate matter may include ultrafine particles such as dust, viruses, metal ions, organic matter, and inorganic particles in the air, and gaseous matter may include harmful gases such as sulfur dioxide, nitrogen oxides, ozone, and carbon monoxide.

[0070] The first embodiment is a method that utilizes electrospinning and electrostatic spraying simultaneously by spraying nanofibers onto a support and coating them, and then coating MOF powders by electrostatic spraying.

[0071] Figure 1 is a flow chart of a method for manufacturing a nanofiber filter according to a first embodiment of the present invention. As shown in Figure 1, the method for manufacturing a nanofiber filter according to the first embodiment includes a step (S110) of electrospinning a solution containing a polymer and an organic solvent onto a support, and a step (S111) of electrospinning MOF (metal-organic framework) powder at 11.7 g / m 2It includes a step (S120) of electrostatically spraying the support with the above coating amount. And, by performing the electrospinning step and the electrostatic spraying step simultaneously, a nanofiber filter coated with nanofibers and MOF powder on the support is manufactured.

[0072] In the first embodiment, to produce a coating layer in which nanofibers ejected from electrospinning and MOF powder sprayed from electrostatic spraying are dispersed, electrospinning and electrostatic spraying may be performed simultaneously, but may be performed in the same direction or in different directions.

[0073] For example, when performed in the same direction, the nozzle of electrospinning and the nozzle of electrostatic spraying may be performed in the upward, downward, leftward, or rightward direction on the plane of the support, but are not limited thereto.

[0074] When performed in different directions, they may be performed in directions facing each other, orthogonal to each other, or intersecting directions, but are not limited thereto.

[0075] By performing electrospinning and electrostatic spraying simultaneously, MOF powder can be sufficiently coated on the surface of nanofibers, and MOF powder can be sufficiently coated between one nanofiber and another. In addition, by performing electrospinning and electrostatic spraying simultaneously, the coating amount of MOF powder can be 11.7 g / m 2 The controllability is as described above, and the uniform dispersion of MOF powder on the support can be achieved. Accordingly, the effect of simultaneously reducing particulate matter and gaseous matter is achieved without increasing pressure loss.

[0076] The second embodiment is a method in which electrospinning and electrostatic spraying are alternately used at least once by producing a nanofiber layer by electrospinning nanofibers onto a support, and then coating MOF powder by electrostatic spraying to produce a MOF powder layer.

[0077] FIG. 2 is a flowchart of a method for manufacturing a nanofiber filter according to a second embodiment of the present invention. As illustrated in FIG. 2, the method for manufacturing a nanofiber filter according to the second embodiment is characterized by including a step (S210) of manufacturing a nanofiber layer by electrospinning a solution containing a polymer and an organic solvent onto a support, a step (S220) of manufacturing an MOF (metal-organic framework) powder layer by electrostatically spraying MOF powder onto the nanofiber layer, and a step (S230) of alternately stacking a nanofiber layer and an MOF powder layer by performing steps S210 and S220 at least once.

[0078] In the present invention, steps S210 and S220 may be performed at least once, preferably at least twice, and more preferably at least three times. Through the step (S230) of alternately stacking the nanofiber layer and the MOF powder layer, the nanofiber layer or the MOF powder layer may be positioned on the outermost layer of the nanofiber filter, and preferably, the nanofiber layer may be positioned on the outermost layer of the nanofiber filter.

[0079] In the first embodiment or the second embodiment, the electrospinning may include the steps of filling a syringe with a solution, providing a collecting plate so as to be spaced apart from the syringe, placing a support on the collecting plate, and applying a voltage to the syringe, such that nanofibers are discharged from a nozzle of the syringe by the applied voltage, thereby coating the support with nanofibers.

[0080] The solution is discharged and becomes nanofibers, and may contain a polymer in powder or chip form as a nanofiber raw material.

[0081] The polymer may include one or more of polypropylene (PP), polyurethane (PU), polyether sulfone, polyester (PES), polyimide (PI), polymethyl methacrylate (PMMA), nylon, polystyrene (PS), Teflon (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and polyacrylonitrile (PAN).

[0082] Polypropylene (PP) is economical, durable, and chemically stable. Polyurethane (PU) offers excellent elasticity and abrasion resistance. Polyester (PES) has excellent heat resistance and high strength. Polymethyl methacrylate (PMMA) offers excellent chemical stability. Nylon offers strength, durability, and abrasion resistance. Polystyrene (PS) offers economic efficiency and lightweight properties. Teflon (PTFE) is chemically very stable and has excellent strength. Polyvinylidene fluoride (PVDF) offers excellent chemical stability, heat resistance, and abrasion resistance. Polyvinyl alcohol (PVA) has excellent solubility, high absorbency, and physical strength. Polyacrylonitrile (PAN) offers excellent strength and abrasion resistance.

[0083] These materials can be made into fine fibers through an electrospinning process to maximize their properties.

[0084] For example, the polymer may be present in an amount of 5 to 30 wt% relative to the total 100 wt% of the solution, but is not limited thereto. When the concentration of the polymer is within a range of 5 to 30 wt%, it is advantageous in producing nanofibers with a complete shape during electrospinning and reducing particulate matter. A complete fiber shape may mean that one fiber strand is connected or not connected to another, and that the diameter and surface properties of one fiber strand are uniform.

[0085] An organic solvent may be included to dissolve the polymer and control the viscosity of the solution.

[0086] The organic solvent may include at least one of dimethylformamide (DMF), diethylformamide (DEF), dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and methylpyrrolidone (NMP), and preferably at least two of them. The content of the organic solvent is the content excluding the polymer content in the solution, and may be the remainder.

[0087] In the step of preparing a solution by mixing a polymer and an organic solvent, the polymer and the organic solvent can be mixed at 70 to 80°C for 1 to 24 hours, and preferably, the solution can be prepared by mixing at 70 to 80°C for 10 to 20 hours.

[0088] The viscosity of the prepared solution may be, but is not limited to, 1000 cp to 9000 cp.

[0089] After measuring the viscosity and electrical conductivity of the solution to determine whether the polymer is completely dissolved in the solution, the solution can be injected into a syringe used for electrospinning.

[0090] The syringe is controlled by a pump. When the pump is used, the discharge amount is controlled by a motor, and the solution is transferred to a metal nozzle through tubing connected to the syringe. The diameter of the metal nozzle can range from 0.3 to 0.6 mm, and the flow rate of the transferred solution can be adjusted according to the diameter of the nozzle. In addition, the nozzle must be connected to a voltage line so that a high-voltage generator can be used to apply voltage. The collecting plate located opposite the nozzle can be grounded or an electric field can be artificially created by applying a voltage opposite to the voltage applied to the nozzle.

[0091] The collecting plate located opposite the nozzle must be made of a metal material or a material that conducts electricity well. A support capable of collecting nanofibers can be positioned on the collecting plate. The support can protect the nanofibers from the outside. The support can be a porous non-woven fabric or woven fabric made of a fiber material, and can have properties required by the filter, such as durability and chemical stability. From this perspective, the support can include one or more woven or non-woven fabrics selected from polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyurethane (PU), polyester (PES), polyimide (PI), polymethyl methacrylate (PMMA), nylon, polystyrene (PS), and polyvinyl alcohol (PVA).

[0092] Polypropylene (PP), polyethylene (PE), nylon, and polyethylene terephthalate (PET) are strong and durable materials that can provide the necessary physical strength and durability in the manufacturing process of dry-laid nonwoven fabrics. These materials are stable at high temperatures, chemically stable, and easy to process, allowing them to be manufactured into a variety of shapes. This provides advantages in diversifying filter designs and structures. Furthermore, these materials can enhance the physical properties of nonwoven fabrics, improving their strength and heat resistance. Their economical efficiency also reduces manufacturing costs.

[0093] The support has fine fibers that provide a large surface area to physically capture particles and / or gases, and can exhibit high strength and durability. From this perspective, the support may include one or more types of short fibers and long fibers. The short fibers and long fibers may have lengths ranging from 1 to 1000 μm, and the long fibers may be at least 0.5 times longer than the short fibers, but are not limited thereto. In addition, the diameters of the short fibers and long fibers may range from 0.1 to 1000 μm, but are not limited thereto.

[0094] A support composed of at least one type of short fiber or long fiber increases the physical particle capture effect of the fine fibers by providing a larger surface area. Since the support is composed of at least one type of short fiber or long fiber at different intervals and distributions, fine dust or foreign matter is trapped between the short fibers and / or long fibers. Consequently, the dust or foreign matter particles are effectively filtered, which is beneficial for air purification. Furthermore, a support composed of long fibers can have higher strength and durability than short fibers, which is beneficial for extending the life of the filter.

[0095] When the solution begins to form on the nozzle and is visible to the naked eye, voltage can be applied from a high-voltage generator. By increasing the voltage so that the external electric field is stronger than the surface tension determined by the viscosity of the solution inside the nozzle, the circular droplets can be stably formed into an umbrella-shaped Taylor cone. Through this process, nanofibers in a complete fiber form are ejected from the nozzle, performing electrospinning and attaching the nanofibers to the support.

[0096] For the radiation conditions, a voltage of 9 to 25 kV may be applied to the nozzle, the distance between the nozzle and the collecting plate may be 10 to 15 cm, or the electrospinning may be performed in an atmosphere of 22 to 30°C and 25 to 31% humidity, or at least one of these conditions may be satisfied.

[0097] In the first or second embodiment, the electrostatic spraying may include a step of injecting a solution containing MOF powder into a nozzle and applying voltage to spray MOF powder in the form of droplets onto a support through the nozzle.

[0098] Specifically, in a binder-free process, MOF powder is mixed with an organic solvent to produce a dispersed solution of MOF powder. The addition of a binder increases the size of the MOF powder, making it unsuitable for use in a spinning process. Therefore, it is desirable to produce a dispersed solution of MOF powder in a binder-free form. Organic solvents in MOF powder solutions may include ethanol, methanol, ethyl acetate, and the like.

[0099] The MOF powder may be contained in an amount of 5 to 30 wt%, preferably 10 to 20 wt%, based on 100 wt% of the total solution. If the MOF powder content is less than 5 wt%, the energy consumption is greater than the amount coated during electrostatic spraying. Conversely, if the MOF powder content exceeds 30 wt%, there is a problem in that the MOF powder is not sprayed.

[0100] MOF powder is coated on the support by electrostatic attraction between the support and the nozzle, and the MOF powders can be coated while being spaced apart from each other. For example, by applying a voltage of 10 to 15 kV, a (+) charge is formed in the MOF powder solution inside the nozzle, and a (-) charge is formed on the support. The MOF powder in the solution can be coated by the (+) charge.

[0101] Through electrostatic spraying, MOF powder in droplet form is uniformly dispersed and coated at the molecular level. MOF powder with an average diameter of 0.3 μm to 10 μm can be coated on a support with a uniform distribution without agglomeration. Preferably, fine MOF powder with an average diameter of 0.4 to 5 μm can be coated.

[0102] By ensuring that the average diameter of the MOF powder in droplet form is between 0.3 µm and 10 µm, excellent coating properties of the MOF powder can be achieved on the nanofiber surface. Furthermore, this has a beneficial effect in simultaneously reducing particulate matter and gaseous matter without increasing pressure loss.

[0103] In the second embodiment, at step S220, the MOF powder was added at 11.7 g / m 2 Electrostatic spraying is possible with the above coating amount, preferably 11.7 to 35 g / m 2 Electrostatic spraying can be performed with a coating amount of 11.7 g / m2. The coating amount of MOF powder as an adsorbent is 11.7 g / m2. 2 By satisfying these ideals, a large amount of MOF powder can be coated under conditions combining electrospinning and electrostatic spraying. Furthermore, the effect of simultaneously reducing particulate matter and gaseous matter without increasing pressure loss is achieved.

[0104] In the first or second embodiment, the MOF powder is a porous organic-inorganic polymer compound formed by a central metal ion bonded to an organic ligand through molecular coordination bonding. Furthermore, the MOF powder is a crystalline compound with a pore structure, containing both organic and inorganic substances within its framework. Such MOF powder can function as an adsorbent as a porous material, thereby exhibiting a gaseous substance reduction effect.

[0105] Specifically, the metal ion may be one or more of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, La, W, Os, Ir, Pt, Au, Hg, Sm, Eu, Gd, Tb, Dy, Ho, Al, Ga, In, Ge, Sn, Pb, Li, Na, K, Rb, Cs, Mg, Ca, Sr, and Ba.

[0106] Organic ligands include 1,4-benzenedicarboxylic acid (BDCA), isophthalic acid, 1,3,5-benzenetricarboxylic acid (BTCA), 2,5-dihydroxyterephthalic acid, 2-aminoterephthalic acid, 2-nitroterephthalic acid, 2-methylterephthalic acid, 2-haloterephthalic acid, azobenzene tetracarboxylic acid, 1,3,5-tri(4-carboxyphenyl)benzene, 2,6-naphthalene dicarboxylic acid (NDCA), benzene-1,3,5-tribenzoic acid (BTB), fumaric acid, glutaric acid, 2,5-furanedicarboxylic acid (FDCA), 1,4-pyridinedicarboxylic acid, 2-methylimidazole, alkylsubstituted imidazole, aromatic ringsubstituted imidazole, 2,5-pyrazinedicarboxylic acid, 1,4-benzene dipyrazole, 3,5-dimethyl-pyrazolate-4-carboxylate, 4-(3,5-dimethyl-1H-pyrazol-4-yl) benzoate, 1,4-(4-bispyrazolyl) benzene, deprotonated 2-methylimidazole, 4,4'-biphenyldicarboxylic acid, 1,3,6,8-tetrakis(p-benzoic acid)pyrene, tetrakis(4-carboxyphenyl)porphyrin, 1,1'-biphenyl-3,3',5,5'-tetracarboxylic acid and N,N,N',N'-tetrakis(4-carboxyphenyl)-biphenyl-4,4'-diamine It may contain one or more of (N,N,N',N'-tetrakis(4-carboxyphenyl)-biphenyl-4,4'-diamine: TCBTDA);

[0107] According to the first embodiment, a nanofiber filter is manufactured in which a coating layer is disposed on one side of a support, and the coating layer includes nanofibers and MOF powder dispersed at a uniform concentration, or according to the second embodiment, a nanofiber filter is manufactured in which a nanofiber layer and a MOF powder layer are alternately laminated on a support, and then the nanofiber filter can be separated from the collection plate to measure the collection efficiency and pressure loss.

[0108] Figure 3 is a cross-sectional view of a nanofiber filter according to the first embodiment of the present invention.

[0109] As shown in FIG. 3, the nanofiber filter according to the first embodiment includes a support (10) and a coating layer disposed on one surface of the support, and the coating layer includes nanofibers (20) and MOF (metal-organic framework) powder (30), and the content of the MOF powder (30) is 11.7 g / m. 2 It is characterized by the following:

[0110] The content of MOF powder can be confirmed in the nanofiber filter state.

[0111] The MOF powder content can vary depending on the type of support used. For example, assuming PET material CCL70 is used as the support, the figure "70" refers to the fiber weight per unit area. Furthermore, nanofibers produced by spinning also weigh approximately 2 g per unit area. By measuring the weight of a sample per unit area after cutting it from the product, the MOF powder content can be calculated.

[0112] Figure 4 is a cross-sectional view of a nanofiber filter according to a second embodiment of the present invention.

[0113] As illustrated in FIG. 4, a nanofiber filter according to a second embodiment includes a support (100), a nanofiber layer (200) disposed on the support, and a MOF (metal-organic framework) powder layer (300) disposed on the nanofiber layer, and is characterized in that the nanofiber layer (200) and the MOF powder layer (300) are alternately laminated at least once.

[0114] In the second embodiment, the content of MOF powder in the MOF powder layer is 11.7 g / m 2 This may be unusual, and the details are the same as those described above, so they will be omitted.

[0115] In the first or second embodiment, the average diameter of the MOF powder may be greater than 0.3 μm and less than or equal to 10 μm. By satisfying the average diameter of the MOF powder to be greater than 0.3 μm and less than or equal to 10 μm, there is an effect of simultaneously reducing particulate matter and gaseous matter without increasing pressure loss.

[0116] Destructive methods can be used to measure the average diameter of MOF powder in a nanofiber filter. This method involves cutting the product and analyzing the cross-section using an SEM to measure the diameter of the MOF powder electrostatically sprayed onto the support.

[0117] Therefore, the nanofiber filter according to the first and second embodiments of the present invention has the effect of simultaneously reducing particulate matter and gaseous matter without increasing pressure loss. The pressure loss may be 0.8 mmAq or less, and preferably 0.7 mmAq or less.

[0118] Additionally, the nanofiber filters according to the first and second embodiments can exhibit a gaseous substance removal efficiency of 48% or higher. For example, the formaldehyde removal efficiency can exhibit 57% or higher. The toluene removal efficiency can exhibit 48% or higher.

[0119] These nanofiber filters can be applied to outdoor and indoor air purifiers.

[0120] Here, specific examples of nanofiber filters and their manufacturing methods are as follows.

[0121] 1. Nanofiber filter and its manufacturing method

[0122] Psalms 1–3

[0123] On the support, a nanofiber layer was manufactured by electrospinning a solution containing a polymer (PESU7020 (Poly Ether Sulfone) / 18-19 wt%) and an organic solvent (DMF:NMP=8:2).

[0124] MOF powder (metal-organic ligand) was electrostatically sprayed (15 to 20 kV) onto the nanofiber layer to produce a layer of MOF powder (average diameter of more than 0.3 μm to 1 μm).

[0125] Specifically, a spinning solution was prepared, injected into a syringe, and then discharged to the nozzle by controlling the flow rate with a controlled pump. When the strength of the external electric field applied was greater than the surface tension of the spinning solution, the electrospun solution flew in the form of fibers and attached to the collecting plate on the opposite side. The electrostatic spray flew in the form of particles and attached to the collecting plate on the opposite side.

[0126] Nanofiber filter specimens 1 to 3 were manufactured through a step of alternately laminating nanofiber layers and MOF powder layers.

[0127] Sample 1 is a sample in which a support, nanofiber layer, MOF powder layer, and nanofiber layer are laminated in that order.

[0128] Sample 2 is a sample in which a support, a nanofiber layer, a MOF powder layer, a nanofiber layer, a MOF powder layer, a nanofiber layer, a MOF powder layer, and a nanofiber layer are laminated in that order.

[0129] Sample 3 is a sample in which a support, a nanofiber layer, a MOF powder layer, a nanofiber layer, a MOF powder layer, a nanofiber layer, a MOF powder layer, a nanofiber layer, a MOF powder layer, a nanofiber layer, a MOF powder layer, and a nanofiber layer are laminated in that order.

[0130]

[0131] Ref. Psalm

[0132] Bulk granules of MOF or activated carbon were coated on the support.

[0133]

[0134] Air spray support coated specimen

[0135] The coating amount of MOF powder was calculated by measuring the weight of the support each time it was sprayed from a distance of about 30 cm using pneumatic spray equipment or a sprayer.

[0136]

[0137] 2. Physical property evaluation method and results

[0138] 1) Method of measuring pressure loss and filtration efficiency of the filter itself: After cutting the specimen to about 110 mm using TSI8130A equipment, the measurement was made by introducing 0.3 μm NaCl particles at a flow rate of 5.3 cm / s.

[0139] 2) The SEM images of Fig. 6, Fig. 8, and Fig. 10 were measured by request from the Korea Institute of Industrial Technology (Cheonan) and observed using JEOL equipment.

[0140] Table 1 shows the pressure loss and filtration efficiency of the filter itself for each detailed specimen.

[0141] Binderless MOF powder specimen number, pressure loss, filtration efficiency of the filter itself, desorption ratio, mmAq%, coating amount of MOF powder: 11.7 g / m 2Specimen 1 of Fig. 5: 2 layers of nanofibers, 1 layer of MOF powder 1-10.215.771% 1-20.221.071-30.222.021-40.223.84 (average) 1-50.220.68 Specimen 2 of Fig. 7: 4 layers of nanofibers, 3 layers of MOF powder 2-10.256.031% 2-20.256.362-30.360.012-40.251.86 (average) 2-50.2356.07 Specimen 3 of Fig. 9: 6 layers of nanofibers, 5 layers of MOF powder 3-10.876.381.50% 3-20.6723-30.572.223-40.775.06 (average) 3-50.6573.92

[0142] Table 2 shows the removal efficiency for gaseous substances for each average specimen.

[0143] Binderless Ref. Air spray support coating nanofiber layer and MOF powder layer lamination coating condition 35 g / m 2 MOF powder coating weight 11.7g / m 2 MOF powder coating weight 23.4g / m 2 MOF powder coating weight 35.1g / m 2 MOF powder coating amount: 11.7g / m 2 Granularity 5 (average) 1-5 7 (average) 2-5 9 (average) 3-5 Pressure loss (mmAq) 0.2 0.2 0.5 2.8 0.2 0.2 3 0.65 Won Pass efficiency (%) Formaldehyde 60 58.8 59.2 4.7 6 1.9 6 0.5 6 2.2 Toluene 46 35.4 38.6 42.5 48.7 53.2 5 8.1

[0144] Fig. 5 is a cross-sectional view of a nanofiber filter according to Sample 1 of the present invention. Fig. 6 is a SEM image of a nanofiber filter according to Sample 1 of the present invention.

[0145] Referring to Figures 5 and 6, the nanofiber filter specimen manufactured according to the second embodiment is formed by alternately stacking a nanofiber layer and a MOF powder layer on a support once, and then forming a nanofiber layer on the outermost layer. The coating amount of the MOF powder is 11.7 g / m 2, and it can be confirmed that the MOF powder is well coated on the nanofiber surface without agglomeration.

[0146] In particular, for the (average) 1-5 specimens, the pressure loss was 0.2 mmAq. Table 2 shows that the removal efficiency of formaldehyde, a gaseous substance, was 61.9%, and the removal efficiency of toluene was 48.7%.

[0147] Fig. 7 is a cross-sectional view of a nanofiber filter according to Sample 2 of the present invention. Fig. 8 is an SEM image of a nanofiber filter according to Sample 2 of the present invention.

[0148] Referring to Figures 7 and 8, the nanofiber filter specimen manufactured according to the second embodiment is formed by alternately stacking a nanofiber layer and a MOF powder layer on a support three times, and then forming a nanofiber layer on the outermost layer. The coating amount of the MOF powder is 11.7 g / m 2 , and it can be confirmed that the MOF powder is well coated on the nanofiber surface without agglomeration.

[0149] In particular, for the (average) 2-5 specimens, the pressure loss was 0.23 mmAq. Table 2 shows that the removal efficiency of formaldehyde, a gaseous substance, was 60.5%, and the removal efficiency of toluene was 53.2%.

[0150] Fig. 9 is a cross-sectional view of a nanofiber filter according to sample 3 of the present invention. Fig. 10 is a SEM image of a nanofiber filter according to sample 3 of the present invention.

[0151] Referring to Figures 9 and 10, the nanofiber filter specimen manufactured according to the second embodiment is formed by alternately stacking a nanofiber layer and a MOF powder layer on a support five times, and then forming a nanofiber layer on the outermost layer. The coating amount of the MOF powder is 11.7 g / m 2 , and it can be confirmed that the MOF powder is well coated on the nanofiber surface without agglomeration.

[0152] In particular, for the (average) 3-5 specimens, the pressure loss was 0.65 mmAq because they were laminated multiple times. Table 2 shows that the removal efficiency of formaldehyde, a gaseous substance, was 62.2%, and the removal efficiency of toluene was 58.1%.

[0153] Referring to Table 2, the Ref specimen has a granule content of 35 g / m 2 Coated with a coating amount, the pressure loss was 0.2 mmAq. In addition, the removal efficiency of formaldehyde, a gaseous substance, was 60%, and the removal efficiency of toluene was 46%.

[0154] The specimens manufactured by the air spray support coating method had a coating amount of MOF powder of 11.7 g / m 2 36.1g / m 2 As the coating amount of MOF powder increased, the pressure loss also tended to increase. Accordingly, the coating amount of MOF powder was 11.7 g / m 2 When the coating amount of MOF powder was 35.1 g / m, the formaldehyde removal efficiency was 58.8%. 2 At one time, the formaldehyde removal efficiency was 44.7%, which was a considerably low result.

[0155] In contrast, the (average) 1-5 specimens of the present invention had a coating amount of MOF powder of 11.7 g / m 2 (Average) 1-5 specimens were manufactured using air spray support coating method (coating amount 11.7 g / m 2 ), the formaldehyde removal efficiency was higher at 61%.

[0156] The (average) 2-5 specimens of the present invention had a lower coating amount of MOF powder compared to the Reference specimen. Nevertheless, the (average) 2-5 specimens exhibited a higher single-pass efficiency than the Reference specimen.

[0157] The (average) 3-5 specimens of the present invention have a structure in which nanofiber layers and MOF powder layers are alternately laminated five times. Nevertheless, the coating amount of MOF powder is 11.7 g / m 2 As a result, the one-pass efficiency was higher than that of the Ref specimen and the specimen manufactured by the air spray support coating method.

[0158] Therefore, it can be confirmed that the specimen satisfying the present invention has excellent gaseous substance removal efficiency.

[0159] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. (a) a step of electrospinning a solution containing a polymer and an organic solvent onto a support; and (b) a step of electrostatically spraying MOF (metal-organic framework) powder onto the support; By performing the above steps (a) and (b) simultaneously, a nanofiber filter coated with nanofibers and MOF powder on a support is manufactured. In the above step (a), the MOF powder was 11.7 g / m 2 A method for manufacturing a nanofiber filter by electrostatic spraying with the above coating amount. 2.(a) A step of producing a nanofiber layer by electrospinning a solution containing a polymer and an organic solvent onto a support; (b) a step of electrostatically spraying MOF (metal-organic framework) powder onto the nanofiber layer to produce a MOF powder layer; and (c) A method for manufacturing a nanofiber filter, comprising: performing steps (a) and (b) at least once to alternately stack a nanofiber layer and a MOF powder layer.

3. In paragraph 1 or 2, A method for manufacturing a nanofiber filter wherein the average diameter of the above MOF powder is more than 0.3㎛ and less than 10㎛.

4. In paragraph 1 or 2, The above electric radiation After filling the above solution into a syringe, a step of preparing a collecting plate to be spaced apart from the syringe and placing a support on the collecting plate; and A method for manufacturing a nanofiber filter, comprising: a step of applying voltage to the syringe, thereby coating nanofibers on a support while discharging nanofibers from a nozzle of the syringe by the applied voltage.

5. In paragraph 1 or 2, A method for manufacturing a nanofiber filter, comprising the steps of: injecting a solution containing MOF powder into a nozzle, applying voltage, and spraying MOF powder in the form of droplets onto a support through the nozzle; 6. In paragraph 2, In the above step (b), the MOF powder is 11.7 g / m 2 A method for manufacturing a nanofiber filter by electrostatic spraying with the above coating amount.

7. In paragraph 1 or 2, The above MOF powder is a metal ion and an organic ligand coordinately bonded, The above metal ions include at least one of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, La, W, Os, Ir, Pt, Au, Hg, Sm, Eu, Gd, Tb, Dy, Ho, Al, Ga, In, Ge, Sn, Pb, Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba, The organic ligands are 1,4-benzenedicarboxylic acid (BDCA), isophthalic acid, 1,3,5-benzenetricarboxylic acid (BTCA), 2,5-dihydroxyterephthalic acid, 2-aminoterephthalic acid, 2-nitroterephthalic acid, 2-methylterephthalic acid, 2-haloterephthalic acid, azobenzene tetracarboxylic acid, 1,3,5-tri(4-carboxyphenyl)benzene, 2,6- 2,6-naphthalene dicarboxylic acid (NDCA), benzene-1,3,5-tribenzoic acid (BTB), fumaric acid, glutaric acid, 2,5-furanedicarboxylic acid (FDCA), 1,4-pyridinedicarboxylic acid, 2-methylimidazole, alkylsubstituted imidazole, aromatic ringsubstituted imidazole, 2,5-pyrazinedicarboxylic acid, 1,4-benzene dipyrazole, 3,5-dimethyl-pyrazolate-4-carboxylate, 4-(3,5-dimethyl-1H-pyrazol-4-yl) benzoate, 1,4- 1,4-(4-bispyrazolyl) benzene, deprotonated 2-methylimidazole, 4,4'-biphenyldicarboxylic acid, 1,3,6,8-tetrakis(p-benzoic acid)pyrene, tetrakis(4-carboxyphenyl)porphyrin, 1,1'-biphenyl-3,3',5,5'-tetracarboxylic acid and A method for manufacturing a nanofiber filter comprising at least one of N,N,N',N'-tetrakis(4-carboxyphenyl)-biphenyl-4,4'-diamine (TCBTDA).

8. Support; and A coating layer disposed on one surface of the support; The above coating layer includes nanofibers and MOF (metal-organic framework) powder, The content of the above MOF powder is 11.7 g / m 2 Ideal nanofiber filter.

9. Support; A nanofiber layer disposed on the support; and A MOF (metal-organic framework) powder layer disposed on the nanofiber layer; A nanofiber filter in which the above nanofiber layer and MOF powder layer are alternately laminated at least once.

10. In paragraph 9, The content of MOF powder in the above MOF powder layer is 11.7 g / m 2 Ideal nanofiber filter.

11. In paragraph 8 or 9, A nanofiber filter having an average diameter of the above MOF powder of more than 0.3㎛ and less than 10㎛.

Images