KR102063675B1 - Filter media, method for manufacturing thereof and Filter unit comprising the same - Google Patents

Abstract

Filter media are provided. Filter media according to an embodiment of the present invention comprises a first support having a plurality of pores; A nanofiber web disposed on and under the first support, the nanofiber web including a nanofiber having a three-dimensional network structure and a silver (Ag) antimicrobial layer formed on at least a portion of an outer surface of the nanofiber; And a second support having a plurality of pores interposed between the first support and the nanofiber web, respectively. According to this, as the nanofiber web contains silver, it is possible to sterilize (sterilize) various bacteria contained in the water to be treated, and thus can be variously applied in various water treatment fields. In addition, the filter media of the present invention is formed by laminating the first support having a thicker thickness and the second support thinner than the nanofiber web and the first support having excellent bonding force. Deformation and damage are minimized and the flow path is smoothly secured to have a high flow rate. In addition, due to the excellent durability of the filter medium in the high pressure applied during backwashing has a prolonged use cycle can be applied in various applications in various water treatment fields.

Description

Filter media, method for manufacturing the same, and filter unit including the same

The present invention relates to a filter medium, and more particularly, to a filter medium, a manufacturing method thereof and a filter unit including the same.

The separation membrane may be classified into a microfiltration membrane (MF), an ultrafiltration membrane (UF), a nano separation membrane (NF), or a reverse osmosis membrane (RO) according to the pore size.

The separation membranes exemplified above have a difference in use and pore size, but they have a common feature that they are either a filter medium formed from a fiber or a porous polymer filter medium or in the form of a composite membrane.

On the other hand, in the pores of the filter medium that has been repeatedly subjected to the water treatment process, some of the various foreign substances contained in the water to be treated may remain or form an adhesion layer on the surface of the filter medium. there is a problem. In order to solve this problem, it is common to apply a high pressure to the filter medium so as to be in the opposite direction to the path through which the treated water flows into the filter medium and is filtered and discharged. However, the high pressure applied when the filter medium is washed may cause damage to the filter medium, and in the case of the filter medium having a multi-layer structure, a problem of separation between layers may occur.

Meanwhile, along with well-being winds, the use of materials to provide sterilizing power to air purifiers, air conditioner filters, automotive air filters, and various water purifier filters is increasing.

Accordingly, even in the backwashing process performed at a high pressure, the shape, structural deformation and damage of the media are minimized, and the flow path is smoothly secured, thus having a large flow rate and a fast processing speed, and an antibacterial filter that can filter out harmful microorganisms. Development of media is urgently needed.

Republic of Korea Patent Publication No. 10-0871440

The present invention has been made in view of the above, and an object thereof is to provide a filter medium having excellent antibacterial and bactericidal properties and a method of manufacturing the same.

In addition, it is an object of the present invention to provide a filter medium having a large flow rate and a high treatment speed and a method of manufacturing the same, as the shape, structural deformation, and damage of the filter medium are minimized during water treatment operation and the flow path is smoothly secured.

In addition, another object of the present invention is to provide a filter medium having excellent durability and a method of manufacturing the same, which can ensure a flow path even at a high pressure applied in a backwashing process, and can minimize layer separation and damage to a membrane.

In addition, another object of the present invention is to provide a flat filter unit that can be variously applied in the water treatment field through a filter medium having excellent water permeability and durability.

The present invention to solve the above problems, the first support having a plurality of pores; A nanofiber web disposed on and under the first support, the nanofiber web including a nanofiber having a three-dimensional network structure and a silver (Ag) antimicrobial layer formed on at least a portion of an outer surface of the nanofiber; And a second support having a plurality of pores interposed between the first support and the nanofiber web, respectively.

According to one embodiment of the invention, the silver antimicrobial layer may be formed to be deposited to cover a portion of the outer surface of the nanofiber or plated to cover the whole.

In addition, the silver antimicrobial layer may have an average thickness of 5 ~ 120nm.

In addition, the weight of the silver antibacterial layer may be 30 to 500% of the weight of the total nanofibers.

In addition, the nanofiber web may have an average pore size of 0.1 ~ 3㎛, porosity may be 50 ~ 90%.

In addition, the nanofibers may have an average diameter of 50 ~ 450nm.

In addition, the first support and the second support may be any one of a nonwoven fabric, a woven fabric and a knitted fabric.

In addition, the first support may include a first composite fiber disposed to expose at least a portion of the low melting point component to the outer surface, including a support component and a low melting point component, the low melting point component of the first composite fiber And a first support and a second support by fusion between the low melting point components of the second composite fiber.

In addition, the first support, the thickness may be 90% or more of the total thickness of the filter medium, the basis weight may be 250 ~ 800 g / ㎡.

The second support may include a second composite fiber including a support component and a low melting component such that at least a portion of the low melting component is exposed to an outer surface, and the low melting point of the second composite fiber. The component may be fused to the nanofiber web.

In addition, the basis weight of the second support may be 35 ~ 80g / ㎡, the thickness may be 150 ~ 250㎛.

On the other hand, the present invention comprises the steps of (1) forming a fibrous web with nanofibers formed by electrospinning the spinning solution; (2) preparing a nanofiber web by providing a silver (Ag) antimicrobial layer on at least a portion of an outer surface of the nanofiber; (3) laminating the nanofiber web and the second support; And (4) arranging and laminating the nanofiber web and the second support respectively laminated on both surfaces of the first support such that the second support contacts the first support.

According to an embodiment of the present invention, the step (2) may use an electroless plating method.

In addition, the step (2) before the step of pre-treating the surface of the nanofibers to improve the adhesion of the silver to the nanofibers; may further include.

In addition, the pretreatment may be a catalyst treatment step or a nanofiber etching step.

Further, step (2) is selected from the group consisting of sputtering, ion plating, arc deposition, ion beam assisted deposition, and resistive heating evaporation. It can be either.

In addition, before the step (2), the step of washing the nanofiber web; And forming a primer layer having a nonvolatile polarity on the washed nanofiber web surface.

On the other hand, the present invention is the filter medium described above; And a flow path through which the filtrate filtered from the filter medium flows out, and a support frame supporting the edge of the filter medium.

According to the present invention, as the filter media has silver in the nanofiber web, it can be used in various water treatment fields by having an excellent antibacterial effect such as sterilizing (sterilizing) various bacteria contained in the water to be treated.

In addition, the filter media of the present invention is formed by laminating the first support having a thicker thickness and the second support thinner than the nanofiber web and the first support having excellent bonding force. Deformation and damage are minimized and the flow path is smoothly secured to have a high flow rate. In addition, due to the excellent durability of the filter medium in the high pressure applied during backwashing has a prolonged use cycle can be applied in various applications in various water treatment fields.

1 is a cross-sectional view of the filter medium according to an embodiment of the present invention,
Figure 2 is a schematic diagram of laminating the filter medium according to an embodiment of the present invention, Figure 2a is a view showing the lamination of the nanofiber web and the second support, Figure 2b is a laminated nanofiber web and the second support Figure showing the arrangement and lamination on both sides of the first support,
3 is an SEM image showing the surface of the nanofiber web according to an embodiment of the present invention, and
Figure 4 is a view of a flat plate filter unit according to an embodiment of the invention, Figure 4a is a perspective view of the filter unit, Figure 4b is a schematic diagram showing the filtration flow based on the cross-sectional view of the XX 'boundary line of Figure 4a.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

1, the filter medium 1000 according to an embodiment of the present invention is disposed on the upper and lower portions of the first support 130, the first support 130 having a plurality of pores, respectively, three-dimensional Nanofiber webs 111 and 112 including nanofibers forming a network structure and silver (Ag) antimicrobial layers formed on at least a portion of an outer surface of the nanofibers, and the first support 130 and the nanofiber webs 111, 112 includes second supports 121 and 122 having a plurality of pores interposed therebetween.

The nanofiber webs 111 and 112 are provided on opposing surfaces of the surfaces where the second supports 121 and 122 contact the first support 130, and the nanofiber webs 111 and 112 have one strand. Of nanofibers or strands of nanofibers may be formed randomly arranged.

Filter media formed of general nanofibers can effectively remove a certain amount of fine dust and contaminants, but they do not have any means for sterilizing microorganisms such as bacteria collected with the fine dust. Therefore, the present invention is provided with nanofiber webs (111, 112) including a silver (Ag) antimicrobial layer formed on at least a portion of the outer surface of the nanofibers, while maintaining the ability to remove fine dust and contaminants, and further sterilization power for harmful microorganisms and the like, Implement filter media with improved antibacterial activity.

The silver antimicrobial layer may be formed on the nanofibers or plated on the nanofibers. In this case, when the deposition is formed or plated is formed, the silver antimicrobial layer to be coated according to the difference in the manufacturing method to be described later may have a difference in form. When the silver antimicrobial layer is formed through plating, the silver antimicrobial layer may be formed to cover the entire outer surface of the nanofiber provided in the nanofiber web because the nanofiber web is immersed in a silver plating solution. In addition, when the silver antimicrobial layer is formed through deposition, silver may be deposited only on the nanofibers exposed on the surface from the outer surface of the nanofiber web, so that the outer surface of the nanofibers exposed to cover a portion of the outer surface of the nanofibers The silver antimicrobial layer may be implemented in a form in which only a portion of the surface is coated with silver.

The silver antimicrobial layer has excellent antimicrobial activity and excellent water permeability, and may have an average thickness of 5 to 120 nm, preferably an average thickness of 10 to 100 nm to maintain the antimicrobial activity even after backwashing. For example, the silver antimicrobial layer may have an average thickness of 50 nm. If the thickness of the silver antimicrobial layer is less than 5 nm, the antimicrobial activity may not be expressed to a desired level as the coated silver antimicrobial layer is peeled off during the back washing process in which excessive pressure is applied. In addition, if the thickness of the silver antimicrobial layer is greater than 120nm, it may not be easy to reduce the weight of the filter medium, and the water permeability of the filtrate may decrease as the pore size and porosity decrease.

On the other hand, the average thickness of the silver antimicrobial layer represents the average thickness of the silver antimicrobial layer formed on the outer surface of the nanofiber when the silver antimicrobial layer is formed through plating, and when the silver antimicrobial layer is formed through vapor deposition, It represents the average thickness of the silver antibacterial layer formed on a part of the outer surface of the fiber.

In addition, the silver antimicrobial layer has a weight of 30 to 500%, preferably 50 to 200% of the total weight of the nanofibers in order to achieve an excellent effect at the same time all the antibacterial power, filtration efficiency and durability of the filter medium For example, the weight of the silver antimicrobial layer may be 60% of the total weight of the nanofibers when the silver antimicrobial layer is formed by evaporation. May be%. If the weight of the silver antimicrobial layer is less than 30% of the total weight of the nanofibers, the antimicrobial effect may be lowered. If the weight of the silver antimicrobial layer exceeds 500%, the weight of the filter media may not be easily reduced. The water permeability to may decrease.

Next, the nanofibers forming the nanofiber webs 111 and 112 may be formed of known fiber forming components. However, preferably, in order to express excellent chemical resistance and heat resistance, the fluorine-based compound may be included as a fiber-forming component, and thus, even if the treated water is a solution of a strong acid / strong base or a high temperature solution, a desired level without changing the physical properties of the filter medium As a result, it is possible to secure filtration efficiency / flow rate and have a long use cycle. The fluorine-based compound may be used without limitation in the case of a known fluorine-based compound which may be made of nanofibers. For example, polytetrafluoroethylene (PTFE) -based, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer ( PFA) system, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) system, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (EPE) system, tetrafluoroethylene-ethylene aerial At least one compound selected from the group consisting of copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE) and polyvinylidene fluoride (PVDF) More preferably, the manufacturing cost is low, mass production of nanofibers is easy through electrospinning, and mechanical strength and chemical resistance are good. In one aspect may be a polyvinylidene fluoride (PVDF). In this case, when the nanofibers include PVDF as a fiber forming component, the weight average molecular weight of the PVDF may be 10,000 to 1,000,000, preferably 300,000 to 600,000, but is not limited thereto.

In addition, the nanofibers have an average diameter of 50 to 450 nm, preferably an average diameter of 100 to 400 nm, for example, the nanofibers may have an average diameter of 250 μm, and the thickness of the nanofiber webs 111 and 112 may be It may be 0.5 ~ 200㎛, for example 20㎛, basis weight may be 0.05 ~ 20 g / ㎡, for example 10g / ㎡, but may be appropriately changed in consideration of the desired water permeability and filtration efficiency, In the present invention, this is not particularly limited.

In addition, the nanofiber webs (111, 112) may have an average pore size of 0.1 to 3㎛, preferably 0.15 to 2㎛, for example, may be 0.25㎛. If the average pore diameter of the nanofiber webs 111 and 112 is less than 0.1 μm, the water permeability to the filtrate may be lowered. If the average pore diameter is more than 3 μm, the filtration efficiency of the filter medium may not be good. The effect may be lowered.

The nanofiber webs 111 and 112 may have a porosity of 50 to 90%, preferably 60 to 80%. For example, the nanofiber webs 111 and 112 have a porosity of 70%. Can be. If the porosity of the nanofiber webs (111, 112) is less than 50%, the water permeability to the filtrate may be reduced, if the porosity exceeds 90%, the filtration efficiency of the filter medium may not be good, antibacterial The effect may be lowered.

In addition, the nanofiber webs (111, 112) may be provided in the filter medium 1000 more than one layer, wherein the porosity, pore size, basis weight and / or thickness of each nanofiber web may be different.

Hereinafter, the other structure provided in the filter medium 1000 is demonstrated concretely.

First, the first support 130 supports the filter medium 1000 and forms a large flow path to perform a filtration process or a backwashing process more smoothly. Specifically, when the pressure gradient is formed so that the pressure inside the filter medium is lower than the outside of the filter medium in the filtration process, the filter medium may be compressed. In this case, as the flow path through which the filtrate flows inside the filter medium is significantly reduced or blocked. There is a problem that the flow rate is significantly lowered at the same time a greater differential pressure is applied to the filter medium. In addition, in the backwashing process, an external force may be applied to expand in both directions from the inside of the filter medium, and when the mechanical strength is low, the filter medium may be damaged due to the external force applied.

The first support 130 is provided to prevent the above problems occurring in the filtration process and / or backwashing process, may be a known porous member that is used in the water treatment field, the mechanical strength is secured, for example The first support may be a nonwoven, woven or fabric.

The fabric means that the fibers included in the fabric has a longitudinal direction, the specific structure may be plain weave, twill weave, etc., the density of the warp and weft is not particularly limited. In addition, the knitted fabric may be a known knit tissue, and may be a knitted fabric, a warp knitted fabric, or the like, and may be, for example, a tricot in which yarn is knitted. In addition, as shown in FIG. 1, the first support body 130 may be a non-woven fabric having no longitudinal and lateral direction on the fiber 130a, and may be a dry nonwoven fabric such as a chemical bonding nonwoven fabric, a thermal bonding nonwoven fabric, an airlay nonwoven fabric, a wet nonwoven fabric, a spanless nonwoven fabric, or the like. Known nonwovens may be used which are produced by various methods such as needle punching nonwovens or meltblown.

The first support 130 may express a sufficient mechanical strength and may occupy a thickness of 90% or more of the total thickness of the filter medium in order to prevent durability degradation due to backwashing. For example, the thickness of the first support 130 may be 2 to 8 mm, more preferably 2 to 5 mm, even more preferably 3 to 5 mm, for example the first support ( 130 may be 5 mm thick. If the thickness is less than 2 mm, it may not develop sufficient mechanical strength to withstand frequent backwashing. In addition, when the thickness exceeds 8mm, when the filter medium is implemented as a filter unit to be described later, when implementing a plurality of filter units as a filter module of a limited space, the degree of integration of the filter medium per unit volume of the module may be reduced.

Preferably, the first support 130 may satisfy the thickness condition and at the same time may have a basis weight of 250 to 800 g / m 2, more preferably 350 to 600 g / m 2, for example, the first support ( 130) may have a basis weight of 500 g / m 2. If the basis weight is less than 250 g / ㎡ it may be difficult to express a sufficient mechanical strength, there is a problem that the adhesion to the second support is reduced, if the basis weight exceeds 800 g / ㎡ not enough flow path to form a flow rate This decreases, there may be a problem that smooth backwashing due to the increased differential pressure is difficult.

In addition, when the first support 130 is formed of a fiber such as a nonwoven fabric, the average diameter of the fiber may be 5 ~ 50㎛, preferably 20 ~ 50㎛, for example, the average diameter of the fiber is 35㎛ Can be. In addition, the first support 130 may have an average pore diameter of 20 to 200 μm, preferably 30 to 180 μm, for example, the first support 130 may have an average pore diameter of 100 μm, and porosity. May be 50 to 90%, preferably 55 to 85%, and for example, the first support 130 may have a porosity of 70%, but is not limited thereto. In the filtration process and / or the backwashing process, The above-mentioned nanofiber webs 111 and 112 may be supported to express a desired level of mechanical strength, and at the same time, porosity and pore size that can smoothly form a flow path even at high pressure are not limited.

When the first support 130 is a material used as a support of the separator, there is no limitation in the material thereof. As a non-limiting example, synthetic polymer components selected from the group consisting of polyesters, polyurethanes, polyolefins and polyamides; Alternatively, natural polymer components including cellulose may be used. However, when the first support body has strong brittle physical properties, it may be difficult to expect a desired level of bonding force in the process of laminating the first support body and the second support body. This is because the first support body has a smooth surface like a film. The surface may be macroscopically rugged while forming a porosity, and a surface formed of fibers such as a nonwoven fabric may not have a smooth surface depending on the arrangement of the fibers, the fineness of the fibers, and the degree may vary. Because. If the remaining parts are joined together while there is a part that is not in close contact at the interface between the two layers to be laminated, the part that is not in contact may start the interlayer separation. In order to solve this problem, it is necessary to carry out the lamination process by increasing the adhesion between the two layers by applying pressure from both layers. If the support of the brittle physical properties is strong, the adhesion between the two layers is maintained. There is a limit to increase, the support may be damaged when a higher pressure is applied, the material of the first support is good flexibility, high elongation may be suitable, preferably the excellent support with the second support (121, 122) The first support 130 may be a polyolefin-based material to have.

On the other hand, the first support 130 may include a low melting point component to bind with the second support (121, 122) without a separate adhesive or adhesive layer. When the first support 130 is a fabric such as a nonwoven fabric, the first support 130 may be made of a first composite fiber 130a including a low melting point component. The first composite fiber 130a may include a support component and a low melting point component such that at least a portion of the low melting point component is exposed to an outer surface. For example, a sheath-core composite fiber in which a support component forms a core portion and a low melting component forms a sheath portion surrounding the core portion, or a side-by-side composite fiber in which a low melting component is disposed on one side of the support component. Can be. As described above, the low melting point component and the support component may be preferably polyolefin-based in terms of flexibility and elongation of the support, and for example, the support component may be polypropylene and the low melting component may be polyethylene. At this time, the melting point of the low melting point component may be 60 ~ 180 ℃.

Next, the second supports 121 and 122 disposed on both surfaces of the first support 130 and the nanofiber webs 111 and 112 described above will be described.

The second supports 121 and 122 support the above-described nanofiber webs 111 and 112 and serve to increase the bonding force of each layer provided in the filter medium.

The second supports 121 and 122 are not particularly limited as long as they generally serve as a support for the filter medium, but may preferably be a woven fabric, a knitted fabric, or a nonwoven fabric. The fabric means that the fibers included in the fabric has a longitudinal direction, the specific structure may be plain weave, twill weave, etc., the density of the warp and weft is not particularly limited. In addition, the knitted fabric may be a known knit structure, but may be a knitted fabric, a warp knitted fabric, and the like, but is not particularly limited thereto. In addition, the non-woven fabric means that the fibers included in the longitudinal direction does not have a known, such as chemical bonding non-woven fabric, thermal bonding nonwoven fabric, dry nonwoven fabric such as air nonwoven fabric, wet nonwoven fabric, span nonwoven fabric, needle punched nonwoven fabric or melt blown It is possible to use the nonwoven fabric produced by the conventional method.

For example, the second supports 121 and 122 may be nonwoven fabrics. In this case, the fibers forming the second supports 121 and 122 may have an average diameter of 5 to 30 μm. In addition, the second supports 121 and 122 may have a thickness of 150 μm to 250 μm, more preferably 160 μm to 240 μm, for example, 200 μm.

In addition, the second supports 121 and 122 may have an average pore diameter of 20 to 100 μm, and porosity may be 50 to 90%. However, the present invention is not limited thereto, and the nanofiber webs 111 and 122 may be supported to express a desired level of mechanical strength and may not inhibit the flow of the filtrate flowing through the nanofiber webs 111 and 122. If there is porosity and pore size, there is no restriction. For example, the second supports 121 and 122 may have an average pore diameter of 60 μm and a porosity of 70%.

In addition, the basis weight of the second supports 121 and 122 may be 35 to 80 g / m 2, more preferably 40 to 75 g / m 2, and for example, 40 g / m 2. If the basis weight is less than 35 g / m 2, the amount of fibers forming the second support distributed at the interface formed with the nanofiber webs 111 and 112 may be small. Accordingly, the effective bonding area of the second support in contact with the nanofiber webs may be reduced. Reduction of may not be able to express the desired level of binding force. In addition, there may be a problem that may not develop sufficient mechanical strength to support the nanofiber web, the adhesion with the first support is reduced. In addition, if the basis weight exceeds 80 g / ㎡ it may be difficult to secure the desired flow rate, there may be a problem that smooth backwashing is difficult due to the increased differential pressure.

If the second support (121, 122) is a material used as a support for the filter medium is not limited in the material. As a non-limiting example, synthetic polymer components selected from the group consisting of polyesters, polyurethanes, polyolefins and polyamides; Alternatively, natural polymer components including cellulose may be used.

However, the second supports 121 and 122 may be polyolefin-based polymer components to improve adhesion between the nanofiber webs 111 and 112 and the first support 130. In addition, when the second support bodies 121 and 122 are fabrics such as nonwoven fabrics, the second support bodies 121 and 122 may be made of the second composite fiber 121a including low melting point components. The second composite fiber 121a may be disposed such that at least a portion of the low melting point component is exposed to an external surface including a support component and a low melting point component. For example, a sheath-core composite fiber in which a support component forms a core portion and a low melting component forms a sheath portion surrounding the core portion, or a side-by-side composite fiber in which a low melting component is disposed on one side of the support component. Can be. As described above, the low melting point component and the support component may be preferably polyolefin-based in terms of flexibility and elongation of the support, and for example, the support component may be polypropylene and the low melting component may be polyethylene. At this time, the melting point of the low melting point component may be 60 ~ 180 ℃.

If the above-described first support 130 is implemented with the first composite fiber 130a including a low melting point component to express more improved bonding force with the second support 121, 122, the first support 130 and the first support 130. At the interface between the two supports 121, a more firm fusion can be formed due to the fusion of the low melting point component of the first composite fiber 130a and the low melting point component of the second composite fiber 121a. In this case, the first composite fiber 130a and the second composite fiber 121a may be the same material in terms of compatibility.

On the other hand, the filter medium 1000 according to an embodiment of the present invention can perform the attachment process more stably and easily, expresses a remarkably excellent bonding force at the interface between each layer, high external force is applied due to backwashing, etc. In order to minimize the problem of separation and peeling between layers, the first support 130 and the nanofiber webs 111 and 112 are not directly faced to each other, and the second supports 121 and 122 are thinner. Let's do it.

Referring to FIG. 2A, the second support 3, which occupies less than 10% of the total thickness of the filter media, has a thickness difference from the nanofiber web 2 and the first support 1. As the thickness becomes considerably smaller than the difference between the thicknesses, the heat (H1, H2) applied from above and below the laminate of the nanofiber webs (2) and the second support (3) reaches the interface between them and the fusion (B) It is easy to form. In addition, as it is easy to control the amount and time of heat applied, the nanofiber web 2 is bonded to the second support 3 as shown in FIG. In this case, there is an advantage in that the nanofibers can be bonded with excellent adhesion on the support as shown in FIG. 2 without changing the physical properties of the initially designed nanofiber web 2.

On the other hand, filter filter 1000 according to the present invention comprises the steps of (1) forming a fibrous web with nanofibers formed by electrospinning the spinning solution; (2) preparing a nanofiber web by providing a silver (Ag) antimicrobial layer on at least a portion of an outer surface of the nanofiber; (3) laminating the nanofiber web and the second support; And (4) arranging and laminating the nanofiber web and the second support respectively laminated on both surfaces of the first support such that the second support contacts the first support.

First, the step (1) of forming the fibrous web from the nanofibers formed by electrospinning the spinning solution will be described.

The fibrous web may be used without limitation in the case of a method of forming a fibrous web having a three-dimensional network shape with nanofibers, and preferably, the fibrous web is electrospun onto a second support with a spinning solution containing a fluorine-based compound. To form a fibrous web.

The spinning solution may include, for example, a fluorine compound and a solvent as a fiber forming component. The fluorine-based compound is preferably contained in 5 to 30% by weight, preferably 8 to 20% by weight in the spinning solution, if less than 5% by weight of the fluorine-based compound is difficult to form a fiber, when spinning is not spun into fibrous droplets Even when sprayed to form a film or spinning, beads are formed a lot and the volatilization of the solvent is not made well, the pores may be clogged in the calendaring process to be described later. In addition, if the fluorine-based compound is more than 30% by weight, the viscosity rises and solidification occurs at the surface of the solution, which makes it difficult to spin for a long time, and the fiber diameter may increase, making it impossible to form a fibrous size of micrometer or less.

The solvent may be used without limitation in the case of a solvent which does not generate a precipitate while dissolving a fluorine-based compound which is a fiber-forming component and does not affect the radioactivity of the nanofibers described later, but preferably г-butyrolactone, cyclohexanone, 3 -Hexanone, 3-heptanone, 3-octanone, N-methylpyrrolidone, dimethylacetamide, acetone dimethyl sulfoxide, dimethylformamide may include any one or more selected from the group consisting of. For example, the solvent may be a mixed solvent of dimethylacetamide and acetone.

The prepared spinning solution may be prepared into nanofibers through known electrospinning devices and methods. For example, the electrospinning apparatus may use an electrospinning apparatus having a single spinning pack having one spinning nozzle or a plurality of single spinning packs for mass production or an electrospinning apparatus having a spinning pack having a plurality of nozzles. It is okay. In addition, in the electrospinning method, dry spinning or wet spinning having an external coagulation bath can be used, and there is no limitation according to the method.

When the stirred spinning solution is added to the electrospinning apparatus, a nanofiber web formed of nanofibers may be obtained when electrospinning onto a collector, for example, paper. Specific conditions for the electrospinning is one example, the air spray nozzle provided in the nozzle of the spinning pack may be set to the air pressure of the air injection is 0.01 ~ 0.2 MPa range. If the air pressure is less than 0.01MPa, it does not contribute to the collection and accumulation. If the air pressure exceeds 0.2 MPa, the cone of the spinning nozzle is hardened to block the needle, which may cause radiation trouble. In addition, when spinning the spinning solution, the injection rate of the spinning solution per nozzle may be 10 ~ 30㎛ / min. In addition, the distance between the tip of the nozzle and the collector may be 10 ~ 30cm. However, the present invention is not limited thereto, and may be changed according to the purpose.

On the other hand, before performing step (2) to be described later, in order to impart hydrophilicity to the hydrophilic coating on the outer surface of the nanofibers, but is not limited thereto.

Next, step (2) of preparing a nanofiber web by providing a silver (Ag) antimicrobial layer on at least a portion of the outer surface of the nanofiber will be described.

As described above, the first method of forming a silver antimicrobial layer by plating silver on the nanofibers forming the fibrous web so as to surround the entire outer surface of the nanofiber, and the silver on the nanofibers exposed on one side of the fibrous web. It can be implemented by a second method of forming a silver antimicrobial layer on a portion of the outer surface of the nanofiber by depositing.

First, a first method of forming a silver antimicrobial layer by plating silver on the nanofibers forming the fibrous web to surround the entire outer surface of the nanofibers will be described. Silver plating may be a known silver plating method, but it is preferable to use an electroless plating method in consideration of the properties of the nanofibers. Hereinafter, the electroless plating method will be described based on a method of plating silver on the outer surface of the nanofiber forming the fiber web.

The electroless silver plating method uses a substitution reaction. Generally, a silver plating solution containing a silver complex in a reducible state is immersed in a silver plating solution, and a reducing agent is added to reduce the silver to Ag (Ag). Use silver plating on the surface.

The silver plating solution may be a mixed solution including a reducing solution for substituting silver and a silver providing solution for providing a silver complex. Reducing solutions include inorganic reducing agents such as hydrazine (N 2 H 4), borohydride compounds (lithiumborohydride, sodium borohydride, or aluminum borohydride), sodium hypophosphite (NaH 2 PO 2), and organic reducing agents such as formaldehyde (HCHO) and acetaldehyde (HCHO). CH3CHO, benzaldehyde (C6H5CHO), acroroin (CH2 = CHCHO), glucose, etc. may be used, of which glucose is preferred, and the reducing agent aqueous solution has a reducing agent concentration of 2 to 20. It is preferable to use an aqueous solution of% (w / v).

The silver donor for providing the silver complex may be silver sulfate, silver nitrate, silver chloride, or the like, and any known silver donor may be used without limitation in a range that does not affect the physical properties of the nanofibers.

Silver may be plated on the surface of the nanofibers forming the nanofiber webs 111 and 112 by immersing the nanofiber webs 111 and 112 in the silver plating solution described above, and considering the thickness and the surface area of the silver to be plated, 1 to 10. It can be immersed in the silver plating solution for a time.

If immersed for less than 1 hour, the silver may not be plated sufficiently on the surface of the nanofibers, which may lower the antibacterial and bactericidal performance. In addition, if immersed for more than 10 hours, excessive silver is plated on the surface of the nanofiber, which may cause a problem in the weight reduction of the filter medium, and the size of the pores may be reduced, thereby decreasing the permeability of the filtrate.

In this case, when a reducing agent is added to the silver plating solution, a reduction reaction occurs not only on the surface of the silver plating solution but also in the silver plating solution, so that the surface of the nanofiber web is wetted with a reducing solution in advance before being immersed in the silver plating solution. Silver is reduced only at the surface to avoid unnecessary reduction reactions.

On the other hand, the present invention is a plated silver antimicrobial layer is peeled off due to excessive water pressure than usual when backwashing, or the effectiveness of the antimicrobial is reduced, or the peeled metal particles cause pore closure, breakage and / or contamination of the filtrate due to the peeled metal particles In order to prevent further, the pretreatment process may be performed on the fibrous web before the electroless silver plating step described above. In this case, the pretreatment process may be a catalyst treatment step or nanofiber etching step.

The catalyst treatment step is a pretreatment process for initiating a chemical reaction with a metal on the fiber surface, which is a non-conductor during electroless silver plating, to improve adhesion to the metal. A step for forming a stainless electroless plating film on the surface of the nanofiber. The etching step may be a process for improving wettability and anchor effect of the nanofibers to the plating liquid.

Next, a second method of forming a silver antibacterial layer on a portion of the outer surface of the nanofiber by depositing silver on the nanofibers exposed on one surface of the fibrous web will be described.

The method for depositing silver is selected from the group consisting of sputtering, ion plating, arc deposition, ion beam assisted deposition, and resistive heating evaporation. It may be any one, and, for example, a resistance heating vacuum deposition method may be used as a method of depositing silver.

In the resistive heating vacuum deposition system, a silver deposition material for heating in a vacuum chamber and evaporating to the vapor phase is provided on an upper portion of the hot plate, and a substrate holder may be disposed at a distance to an opposite portion of the silver deposition material.

In the present invention, the fibrous web on which the silver deposition raw material is to be deposited is wound around the first bobbin disposed outside one side of the vacuum chamber, and the fibrous web is guided by a guide roller inside the vacuum chamber to pass through the substrate holder at a constant speed. As the silver deposition raw material evaporates, deposition may be performed on the surface of the fibrous web. Thereafter, the nanofiber webs 111 and 112 on which the silver deposition layers are formed may be drawn out to the outside of the vacuum chamber to be wound on the second bobbin, and thus continuous silver deposition may be performed.

On the other hand, the present invention is a silver antimicrobial layer deposited due to excessive water pressure during backwashing peels off the efficiency of the antimicrobial, or due to the peeled metal particles caused pore closure, breakage and / or contamination of the filtrate due to the peeled metal particles In order to further prevent the formation of the silver antimicrobial layer through the deposition, the surface of the fibrous web may further comprise the step of forming a primer layer that can maximize the adhesion between the antimicrobial layer and the fibrous web.

The primer layer is a process of applying a non-polar polar primer material to a certain thickness and drying, methylmethacrylate, polyether modified dimethylpolysiloxane copolymer, methyl ethyl ketone, vinyl chloride- Vinyl acetate copolymer (vinyl chloride-vinyl acetate copolymer) and toluene may be used.

In addition, the method may further include performing a plasma treatment before deposition by using a plasma generator installed in a vacuum chamber instead of surface treatment of the primer layer. Plasma treatment of the fibrous web activates the surface of the fibrous web, imparting polar functional groups (OH- and H +) to the metal material to be deposited, and cleaning and fine roughening are formed, thereby improving adhesion between the fibrous web and the silver antibacterial layer. You can increase it. The reaction gas used in the plasma treatment may be any one of carbon fluoride (CF 4), argon (Ar), xenon (Ze), helium (He), nitrogen (N 2), oxygen (O 2), or a mixture thereof. Can be.

The nanofiber web prepared by performing the above step (2) may have a silver antimicrobial layer formed on at least a portion of the outer surface of the nanofiber, as shown in FIG. 3.

Next, the step (3) of laminating the nanofiber web and the second support will be described.

When the second support is made of a low melting point composite fiber, binding through the heat fusion of the nanofiber web and the second support may be simultaneously performed through the calendering process.

In addition, a separate hot melt powder or hot melt web may be further interposed to bind the second support and the nanofiber web. At this time, the heat may be applied to 60 ~ 190 ℃, the pressure may be applied to 0.1 ~ 10 kgf / ㎠, but is not limited thereto. However, components such as hot melt powder, which are added separately for binding, frequently generate fumes or melt in the lamination process between supports and supports and nanofibers to close pores, thus achieving the flow rate of the first designed filter media. You may not be able to. In addition, it is preferable to bind the second support and the nanofiber web without being included because it may dissolve during water treatment and cause environmentally negative problems.

Next, the step (4) of placing and laminating the nanofiber web and the second support respectively laminated on both surfaces of the first support such that the second support abuts the first support will be described.

In the step (4), the nanofiber web and the second support laminated on both surfaces of the first support are disposed to be laminated, followed by fusion bonding the first support and the second support by applying one or more of heat and pressure. You can. In this case, a specific method of applying heat and / or pressure may adopt a known method, and a non-limiting example may use a conventional calendering process and the temperature of the applied heat may be 70 to 190 ° C. . In addition, when the calendaring process is performed, it may be divided into several times and may be performed a plurality of times. For example, the second calendaring may be performed after the first calendaring. At this time, the degree of heat and / or pressure applied in each calendaring process may be the same or different. Through the fusion of the first support and the second support may be a bond through the thermal fusion between the second support and the first support, there is an advantage that the separate adhesive or adhesive layer can be omitted.

On the other hand, the present invention provides a flat filter unit including the filter medium manufactured according to the above-described manufacturing method.

As shown in FIG. 4A, the filter medium 1000 may be implemented as a flat plate filter unit 2000. Specifically, the flat filter unit 2000, the filter medium (1000); And a flow path through which the filtrate filtered by the filter medium 1000 flows out, and a support frame 1100 supporting the edge of the filter medium 1000. In addition, an inlet 1110 may be provided in one region of the support frame 1100 to gradient the pressure difference between the outside and the inside of the filter medium 1000. In addition, the support frame 1100 may be formed with a flow path for allowing the filtrate filtered from the nanofiber web to flow to the outside through a support in which the second support and the first support in the filter medium 1000 are stacked. have.

In more detail, in detail, the filter unit 2000 as shown in FIG. 4A applies a suction pressure of a high pressure through the suction port 1110, and the filtrate (P) disposed outside the filter medium 1000 as shown in FIG. 4B. The filtrate Q1, which is directed toward the inside of the filter medium 1000 and filtered through the nanofiber webs 101 and 102, flows along a flow path formed through the support 200 in which the second support / first support is stacked. Inflow into the flow path E provided in the outer frame 1100, and the introduced filtrate Q2 may flow out through the suction port 1110.

In addition, the flat plate filter unit 2000 as shown in Figure 4a can be implemented a plurality of filter modules are provided spaced apart at a predetermined interval in one outer case, such a filter module is again stacked / blocked in a plurality of large A water treatment apparatus can also be comprised.

The filter medium according to the present invention may be variously applied in various water treatment fields by having an excellent antibacterial effect such as sterilization (sterilization) of various bacteria contained in the water to be treated as silver is contained in the nanofiber web. In addition, since the first support having a thick thickness and the second support thinner than the nanofiber web and the first support having excellent bonding force are configured to be laminated, the shape, structural deformation and damage of the filter medium are minimized during the water treatment operation. The flow path can be secured smoothly to have a high flow rate. In addition, due to the excellent durability of the filter medium in the high pressure applied during backwashing has a prolonged use cycle can be applied in various applications in various water treatment fields.

Although the present invention will be described in more detail with reference to the following examples, the following examples are not intended to limit the scope of the present invention, which will be construed as to aid the understanding of the present invention.

<Example 1>

First, in order to prepare a spinning solution, 12 g of polyvinylidene fluoride (Arkema, Kynar761) as a fiber forming component was mixed with 88 g of a mixed solvent in which the weight ratio of dimethylacetamide and acetone was 70:30 at a temperature of 80 ° C. for 6 hours. The solution was prepared by dissolving using a magnetic bar. The spinning solution was put into a solution tank of an electrospinning apparatus and discharged at a rate of 15 µl / min / hole. At this time, the temperature of the spinning section was 30, the humidity was maintained at 50%, the distance between the collector and the spinneret tip was 20 cm. Thereafter, a high voltage generator was used to apply a voltage of 40 kV or more to the spin nozzle pack and at the same time, an air pressure of 0.03 MPa per spin pack nozzle was used to prepare a fiber web formed of PVDF nanofibers. Then, in order to form a hydrophilic coating layer on the outer surface of the nanofibers, 7143 parts of ultrapure water as a solvent was dissolved for 6 hours using a magnetic bar at a temperature of 80 ° C. with respect to 100 parts by weight of polyvinyl alcohol (Kuraray, PVA217) as a hydrophilic polymer. To prepare a first mixture, lowering the temperature of the first mixture to room temperature, and then adding 15 parts by weight of poly (acrylic acid-maleic acid) (Aldrich, PAM) as a crosslinking agent to 100 parts by weight of the hydrophilic polymer. Mixing and dissolving at room temperature for 12 hours to prepare a second mixture. Then, 7143 parts by weight of isopropyl alcohol (Duksan Chemical, IPA) was added to the second mixture and mixed for 2 hours to prepare a hydrophilic coating solution based on 100 parts by weight of the hydrophilic polymer. Thereafter, the fibrous web was dipped in the prepared hydrophilic coating solution and dried at 110 ° C. for 5 minutes to form a hydrophilic coating layer on the outer surface of the nanofibers.

Then, the fibrous web was washed, toluene was applied and dried on the washed nanofiber web to form a primer layer, and silver was deposited by resistance heating vacuum deposition to form a silver antibacterial layer with an average thickness of 50 nm. The nanofiber web having a thickness of 0.8 μm and a porosity of 70% was prepared. In this case, the weight of the silver antimicrobial layer provided in the nanofiber web was 60% of the weight of the total nanofibers. After that, a nonwoven fabric (Namyang Nonwovens Co., Ltd., CCP40) formed of low melting point composite fibers having an average thickness of 200 μm and having a melting point of 120 ° C. as a second part and a polypropylene core part was disposed on one surface of the nanofiber web. Then, a calendering process was performed by applying heat and pressure at a temperature of 140 ° C. and 1 kgf / cm 2 to bond the second support and the nanofiber web.

Then, the laminated second support and the two nanofiber web laminated articles were placed on both sides of the first support such that the second support was in contact with the first support. At this time, the first support was a nonwoven fabric (Namyang nonwoven fabric, NP450) formed of low melting point composite fibers having an average thickness of 5 mm, a melting point of about 120 DEG C as the primary part, and a polypropylene as the core part. Then, the filter medium was prepared by applying heat and a pressure of 1kgf / ㎠ at a temperature of 140 ℃.

<Example 2>

In the same manner as in Example 1, a fiber web formed of PVDF nanofibers was prepared, the cleaning and primer layer formation was changed to etching the nanofibers, and the deposition was carried out in a silver plating solution containing hydrazine and silver nitrate. A filter medium was prepared in the same manner as in Example 1 except for changing to electroless plating by immersion for 5 hours.

<Examples 3 to 8 and Comparative Examples 1 to 3>

Manufactured in the same manner as in Example 1, but as shown in Table 1 and Table 2, the thickness of the silver antimicrobial layer, the weight of the silver antimicrobial layer to the weight of the nanofibers, the average pore diameter, porosity, first support, first The filter medium as shown in Table 1 and Table 2 was prepared by changing the inclusion of a support and a silver antimicrobial layer.

Experimental Example

Each filter medium prepared in Examples and Comparative Examples was implemented in the filter unit as shown in Figure 4a, and the physical properties of the following are shown in Table 1 and Table 2.

1.relative Water permeability  Measure

For the filter unit embodied by the respective filter media prepared in Examples and Comparative Examples, the water permeability per 0.5 m 2 of the specimen area was measured by applying an operating pressure of 50 kPa, and then the water permeability of the filter media of Example 1 was set to 100. Water permeability of the filter media according to the remaining examples and comparative examples was measured based on.

2. Antimicrobial Measurement

The filter units implemented with the respective filter media prepared in Examples and Comparative Examples were measured for antibacterial activity according to KS K 0693: 2011, and used as strains of Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae. ) The bacteriostatic rate against ATCC 4352 was measured.

3. Backwash  Durability rating

For the filter unit implemented with each filter medium prepared in Examples and Comparative Examples, backwashing was performed under conditions that pressurized 400LMH water for 2 minutes per 0.5m2 of the specimen area by applying an operating pressure of 50kPa after immersion in water. After that, when any abnormality does not occur-○, when any problem such as peeling of the silver antibacterial layer, peeling between layers, etc. occurs-back washing durability was evaluated as x.

4. Backwash  Post-microbial measurement

For the filter unit implemented by each filter medium prepared in Examples and Comparative Examples, the antibacterial activity was measured according to KS K 0693: 2011 after performing the backwashing, and used as the strain used Staphylococcus aureus ATCC The bacteriostatic rate after backwash for 6538 and Klebsiella pneumoniae ATCC 4352 was measured.

division Example
One Example
2 Example
3 Example
4 Example
5 Example
6 Silver antibacterial layer formation method deposition Plated Plated Plated Plated Plated Silver antibacterial layer thickness (nm) 50 50 2 10 100 150 Silver Antibacterial Layer Weight (%) 60 133 12 88 189 276 Nanofiber web average pore size (㎛) 0.8 0.75 1.5 1.1 0.53 0.28 Nanofiber web porosity (%) 70 67 82 77 58 53 Whether the first support is included ○ ○ ○ ○ ○ ○ Whether to include the second support ○ ○ ○ ○ ○ ○ Relative Water Permeability (%) 100 98 133 105 82 54 Bacteriostatic rate
(Antibacterial) Staphylococcus (%) 99.9 99.9 99.9 99.9 99.9 99.9 Pneumonia bacterium (%) 99.9 99.9 99.9 99.9 99.9 99.9 Backwash Durability ○ ○ × ○ ○ ○ After backwash
Bacteriostatic rate
(Antibacterial) Staphylococcus (%) 99.9 99.9 78.2 97.7 99.9 99.9 Pneumonia bacterium (%) 99.9 99.9 81.7 98.2 99.9 99.9

division Example
7 Example
8 Comparative example
One Comparative example
2 Comparative example
3 Silver antibacterial layer formation method deposition Plated - Plated Plated Silver antibacterial layer thickness (nm) 5 280 - 50 50 Silver Antibacterial Layer Weight (%) 10 550 - 30 30 Nanofiber web average pore size (㎛) 1.5 0.12 One One One Nanofiber web porosity (%) 85 43 70 70 70 Whether the first support is included ○ ○ ○ ○ × Whether to include the second support ○ ○ ○ × ○ Relative Water Permeability (%) 141 37 100 117 110 Bacteriostatic rate
(Antibacterial) Staphylococcus (%) 99.9 99.9 0 99.9 99.9 Pneumonia bacterium (%) 99.9 99.9 0 99.9 99.9 Backwash Durability × ○ ○ × × After backwash
Bacteriostatic rate
(Antibacterial) Staphylococcus (%) 86.7 99.9 0 72 54.2 Pneumonia bacterium (%) 85.1 99.9 0 67.9 48.8

As can be seen in Table 1 and Table 2 above,

The thickness of the silver antimicrobial layer according to the present invention, the weight of the silver antimicrobial layer to the weight of the nanofibers, the average pore diameter, porosity, the first support, the second support and whether the inclusion of the silver antimicrobial layer, etc. Water permeability, bacteriostatic rate (antibacterial), backwash durability and bacteriostatic after backwashing compared to Examples 3, 6, 7, 8 and Comparative Examples 1 to 3, in which any of these examples 1, 2, 4 and 5 were missing The reduction rate (antimicrobial) was all excellent at the same time.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention may add components within the scope of the same idea. Other embodiments may be easily proposed by changing, deleting, adding, and the like, but this will also fall within the spirit of the present invention.

101, 102, 111, 112: nanofiber web 121, 122: second support
130: first support 1000: filter media
2000, 2000 ': filter unit

Claims (18)

A first support having a plurality of pores;
It is disposed on the upper and lower portions of the first support, respectively, and the nanofibers and the outer surface of the nanofibers that form a three-dimensional network structure is formed to be deposited or plated to cover the whole, the weight of the entire nanofiber A nanofiber web having an average pore diameter of 0.1 to 3 μm and a porosity of 50 to 90%, including a silver (Ag) antimicrobial layer having a thickness of 60 to 189% and an average thickness of 10 to 100 nm; And,
And a second support having a plurality of pores interposed between the first support and the nanofiber web, respectively.
The first support includes a first composite fiber disposed to expose at least a portion of the low melting point component to an outer surface, including a support component and a low melting point component.
The second support includes a second composite fiber arranged to expose at least a portion of the low melting point component to an outer surface, including a support component and a low melting point component.
A filter in which the first support body and the second support body are bound by fusion between the low melting point component of the first composite fiber and the low melting point component of the second composite fiber, and the low melting point component of the second composite fiber is fused to the nanofiber web. Media. delete delete delete delete The method of claim 1,
The nanofiber has an average diameter of 50 ~ 450nm filter media. The method of claim 1,
The first support member and the second support member is any one of a nonwoven fabric, woven fabric and knitted fabric. delete The method of claim 1, wherein the first support,
The thickness is more than 90% of the total thickness of the filter medium,
Filter media having a basis weight of 250 ~ 800 g / ㎡. delete The method of claim 1,
The basis weight of the second support is 35 ~ 80g / ㎡, the thickness is 150 ~ 250㎛ filter media. (1) forming a fibrous web from nanofibers formed by electrospinning a spinning solution;
(2) a silver (Ag) antimicrobial layer having a weight of 60 to 198% and an average thickness of 10 to 100 nm relative to the total weight of the nanofibers by being deposited to cover a part of the outer surface of the nanofibers or plating to cover the whole Preparing a nanofiber web having an average pore size of 0.1 to 3 μm and porosity of 50 to 90%;
(3) laminating the nanofiber web and the second support; And
(4) disposing and laminating the nanofiber web and the second support respectively laminated on both sides of the first support such that the second support abuts the first support;
The first support includes a first composite fiber disposed to expose at least a portion of the low melting point component to an outer surface, including a support component and a low melting point component.
The second support includes a second composite fiber arranged to expose at least a portion of the low melting point component to an outer surface, including a support component and a low melting point component.
A filter in which the first support and the second support are bound by fusion between the low melting point component of the first composite fiber and the low melting point component of the second composite fiber, and the low melting point component of the second composite fiber is fused to the nanofiber web. Media manufacturing method. The method of claim 12,
Step (2) is a filter medium manufacturing method using an electroless plating method. The method of claim 12,
A method of manufacturing a filter medium further comprising the step of pre-treating the surface of the nanofibers to improve the adhesion of silver to the nanofibers before the step (2). The method of claim 14,
Wherein the pre-treatment step is a catalyst treatment step or nanofiber etching step of producing a filter medium. The method of claim 12,
The deposition of step (2) is selected from the group consisting of sputtering, ion plating, arc deposition, ion beam assisted deposition, and resistive heating evaporation. Any one filter medium manufacturing method. The method according to claim 12, wherein before step (2),
Washing the nanofiber web; And
Forming a primer layer having a non-volatile polarity on the surface of the washed nanofiber web. A filter medium according to any one of claims 1, 6, 7, 9, and 11; And
And a support frame having a flow path through which the filtrate filtered from the filter medium flows out, and supporting a frame of the filter medium.

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