KR102055723B1 - 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 hydrophilic polymer compound disposed on and under the first support, each having a three-dimensional network structure and at least a portion of an outer surface of the nanofiber having at least one functional group selected from a hydroxy group and a carboxy group; A nanofiber web comprising a hydrophilic coating layer formed through a hydrophilic coating composition comprising a crosslinking agent having one or more sulfone groups; And a second support having a plurality of pores interposed between the first support and the nanofiber web, respectively. According to this, the filter media can minimize the shape, structural deformation, and damage of the filter media during the water treatment operation, and the flow path is smoothly secured to have a high flow rate. In addition, due to the excellent durability of the filter media, even at high pressure applied during backwashing, it has an extended service life, and the hydrophilic component is uniformly coated on the surface to show excellent water permeability and chemical resistance, and easy to control contamination. As the filtration performance for cation-containing contaminants such as cationic compounds is excellent, it can be variously applied 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.

In general, since most of the filter media materials that can be produced using electrospinning are hydrophobic, the filter media manufactured using the materials show excellent performances in chemical resistance, strength, and the like. Have In order to overcome these disadvantages, a technique for hydrophilizing a filter medium made of a hydrophobic polymer has been tried in various ways.

Typically, there is a method of adsorbing a water-soluble polymer material on the surface of the filter medium, in which case the water-soluble polymer is easily detached from the hydrophobic filter medium when contacted with water to lose hydrophilicity, mainly hydrophilic polymer film only on the surface layer of the filter medium It is disadvantageous because the graft rate is low because it is modified in the form of.

In addition, there is a method of spinning by mixing the fiber-forming component and the hydrophilic polymer material to prepare the filter medium, in this case, it is very difficult to adjust the solubility and residual state of the hydrophilic polymer material, and as a result the filtration characteristics over time There is a problem such as changing or gradually eluting the hydrophilic polymer material.

Accordingly, even in the backwashing process performed at high pressure, the shape, structural deformation, and damage of the media are minimized, and the flow path is smoothly secured, so that it has a large flow rate, a fast treatment water treatment rate, and a balance through hydrophilicity / hydrophobicity. It is an urgent situation to develop a filter medium which can easily control the filtration, and has excellent filtration performance on pollutants carrying cations such as cationic compounds and improved water permeability and chemical resistance.

Republic of Korea Patent Publication No. 10-0871440

The present invention has been made in view of the above, the hydrophilic component is uniformly coated to improve the water permeability and chemical resistance, easy to control contamination, and to the contaminants having a cation such as cationic compounds An object of the present invention is to provide a filter medium having excellent filtration performance and a method of manufacturing the same.

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

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 and a filter module 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 hydrophilic polymer compound disposed on and under the first support, each having a three-dimensional network structure and at least a portion of an outer surface of the nanofiber having at least one functional group selected from a hydroxy group and a carboxy group; A nanofiber web comprising a hydrophilic coating layer formed through a hydrophilic coating composition comprising a crosslinking agent having one or more sulfone groups; 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 present invention, the hydrophilic polymer compound may be polyvinyl alcohol having a polymerization degree of 500 to 2000 and a saponification degree of 85 to 90%.

In addition, the crosslinking agent may include sulfosuccinic acid (sulfosuccinic acid) and poly (styrenesulfonic acid-maleic acid) in a weight ratio of 1: 3 to 10.

In addition, the hydrophilic coating layer may be formed by crosslinking the hydrophilic polymer compound through a crosslinking agent.

In addition, the hydrophilic coating composition may include 80 to 150 parts by weight of a crosslinking agent based on 100 parts by weight of the hydrophilic polymer compound.

In addition, the hydrophilic coating composition may further include a wettability improving agent in an amount of 1,000 to 20,000 parts by weight based on 100 parts by weight of the hydrophilic polymer compound.

In addition, the wettability improving agent may be isopropyl alcohol.

In addition, the hydrophilic coating layer may be formed with a thickness of 5 to 20% of the average diameter of the nanofibers.

In addition, the nanofiber web may have an average pore size of 0.1 ~ 3㎛, porosity may be 40 ~ 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) laminating the fibrous web and the second support to produce a laminate; (3) a hydrophilic coating composition comprising at least a portion of the nanofiber outer surface of the fibrous web provided in the laminate, a hydrophilic polymer compound having at least one functional group selected from a hydroxy group and a carboxyl group and a crosslinking agent having at least one sulfone group Forming a hydrophilic coating layer through; And (4) arranging and stacking laminates each including a hydrophilic coating layer on both sides of the first support such that the second support contacts the first support.

According to an embodiment of the present invention, the step (3) comprises the steps of: (3-1) treating the hydrophilic coating composition to form a hydrophilic coating layer on the laminate; And (3-2) removing the hydrophilic coating layer formed on the second support by washing the laminate on which the hydrophilic coating layer is formed.

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, the filter medium may have a high flow rate by minimizing the shape, structural deformation, and damage of the filter medium during the water treatment operation and smoothly securing the flow path. In addition, due to the excellent durability of the filter media, even at high pressure applied during backwashing, it has an extended service life, and the hydrophilic component is uniformly coated on the surface to show excellent water permeability and chemical resistance, and easy to control contamination. As the filtration performance for cation-containing contaminants such as cationic compounds is excellent, it can be variously applied in various water treatment fields.

1 is a cross-sectional view of the filter medium according to an embodiment of the present invention,
2A and 2B are schematic diagrams showing adsorption to contaminants such as cationic compounds,
Figure 3 is a schematic diagram of laminating the filter medium according to an embodiment of the present invention, Figure 3a is a view showing the lamination of the nanofiber web and the second support, Figure 3b is a laminated nanofiber web and the second support A drawing showing the lamination on both sides of the first support, 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 A hydrophilic coating composition comprising a nanofiber forming a network structure and a hydrophilic polymer compound having at least one functional group selected from a hydroxy group and a carboxy group on at least a part of an outer surface of the nanofiber, and a crosslinking agent having at least one sulfone group. The second support body 121 and 122 having a plurality of pores interposed between the nanofiber webs 111 and 112 including the formed hydrophilic coating layer and the first support 130 and the nanofiber webs 111 and 112, respectively. Include.

In general, filter media formed of only nanofibers having hydrophobic properties have excellent chemical resistance. However, when such a filter medium is applied to the field of water treatment filter, there is a problem that the water permeability is lowered because of its affinity for water due to the hydrophobic property of the filter medium. At this time, by using a sufficient pressure can improve the water permeability of the hydrophobic filter media, but because the required pressure is very high (150 ~ 300 psi), the filter media may be damaged. In addition, there is a problem that is vulnerable to contaminants having a small number of properties and pollutants having a cation, a study on the treatment to give hydrophilic properties and negative charge to the filter medium is required.

Accordingly, the present invention can solve the above problems by implementing a nanofiber web (111, 112) comprising a hydrophilic coating layer formed on at least a portion of the outer surface of the nanofiber.

1, 2A and 2B, the filter medium 1000 according to the present invention includes the second support bodies 121 and 122 and the nanofiber webs 111 and 112 sequentially stacked on the upper and lower portions of the first support 130, respectively. ), And the filtrate filtered from the nanofiber webs (111, 112) has a filtration flow flowing in the direction of the first support (130). At this time, contaminants such as cationic compounds passing through the nanofiber webs 111 and 112 may be effectively filtered as shown in FIGS. 2A and 2B.

More specifically, the general cation-containing fine contaminants may be electrochemically adsorbed by the negative charge and electrostatic attraction of the hydrophilic coating layer coated on the surface of the plurality of nanofibers constituting the nanofiber web. That is, the hydrophilic coating layer may be configured in the form of a polymer in which the negatively charged atoms contained therein are linear or branched, and the contaminants, which are cationic in the filtrate, are adsorbed by the hydrophilic coating layer and the electrostatic attraction to the nanoparticles. It can be filtered by inducing precipitation on the surface of the fibrous web. At this time, the removal performance of the cation-containing contaminants may vary according to the charge density of the negative charge, and such a charge density may be appropriately selected in consideration of the type and the charge density of the desired pollutant.

The hydrophilic coating layer is formed through a hydrophilic coating composition comprising a hydrophilic polymer compound having at least one functional group selected from a hydroxy group and a carboxy group and a crosslinking agent having at least one sulfone group.

The hydrophilic polymer compound may be used without limitation as long as it is a hydrophilic polymer compound having at least one functional group selected from a hydroxyl group and a carboxyl group, and preferably, polyvinyl alcohol (PVA), ethylene vinyl alcohol. (Ethylenevinyl alcohol, EVOH), sodium alginate (Sodium alginate) and the like can be a single or mixed form. For example, polyvinyl alcohol may be used.

When the hydrophilic polymer compound is polyvinyl alcohol, the polyvinyl alcohol may have a degree of polymerization of 500 to 2000, preferably 1500 to 2000, and a degree of saponification of 85 to 90%, preferably 86 to 89%. . For example, the polyvinyl alcohol may have a degree of polymerization of 1800 and a degree of saponification of 88%. If the degree of polymerization of the polyvinyl alcohol is less than 500, even if the formation of the hydrophilic coating layer is not smooth or can be easily peeled off, may not improve the hydrophilicity to the desired level, if the degree of polymerization exceeds 2000, the formation of the hydrophilic coating layer This may be excessive, and thus, the pore structure of the fibrous web layer may be changed or the pores may be closed to reduce porosity and pore size. In addition, if the degree of saponification of the polyvinyl alcohol is less than 85%, the formation of a hydrophilic coating layer may be unstable, the degree of improvement of hydrophilicity may be insignificant, and if the degree of saponification exceeds 90%, hydrogen bonding between polyvinyl alcohol molecules is strong, even at high temperatures. Difficult to dissolve in solvents or difficult to dissolve completely difficult to manufacture a hydrophilic coating layer solution, it may be difficult to produce a hydrophilic coating layer due to this, even if the hydrophilic coating layer is not properly formed or the hydrophilic coating layer is formed unevenly, and some pores may be closed. It may not express the effect.

The crosslinking agent may be used without limitation as long as it is a crosslinking agent having at least one sulfone group which can be used conventionally, and preferably 1 selected from the group consisting of sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid). More than one species can be used. For example, the crosslinking agent may include both sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid).

As the hydrophilic coating layer is formed by crosslinking the hydrophilic polymer compound through a crosslinking agent, the hydrophilic coating layer may be negatively charged at the same time as the hydrophilicity of the filter medium may be improved, and thus the filtration efficiency of the cationic contaminants may be improved.

When the crosslinking agent includes both sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid), the crosslinking agent includes sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid). It may be included in a weight ratio of 3 to 10, preferably in a weight ratio of 1: 5 to 8. For example, the weight ratio of sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid) may be 1: 6.7. If the weight ratio of the sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid) is less than 1: 3, there may be a problem in that the amount of crosslinking with PVA is insufficient, resulting in a decrease in the formation of a hydrophilic coating layer. If the weight ratio exceeds 1:10, there may be a problem in that crosslinking and water permeability are lowered due to self-aggregation.

In addition, the crosslinking agent may be included in the 80 to 150 parts by weight, preferably 90 to 140 parts by weight based on 100 parts by weight of the hydrophilic polymer compound. For example, the crosslinking agent may be included in an amount of 115 parts by weight based on 100 parts by weight of the hydrophilic polymer compound. If the crosslinking agent is less than 80 parts by weight based on 100 parts by weight of the hydrophilic polymer compound, the formability of the hydrophilic coating layer may be lowered, and the chemical resistance and mechanical strength may be lowered, and when the amount is greater than 150 parts by weight, the crosslinking agent in the hydrophilic coating composition As the cross-linking reaction is less likely to occur uniformly as the agglomeration of the liver occurs, the coating layer may be formed nonuniformly, or the flow rate may be reduced due to the reduction of pores due to the coating layer.

On the other hand, due to the strong hydrophobicity, which is the material property of the nanofibers forming the fabric web layer, even if the hydrophilic coating composition is treated, the coating composition does not penetrate into the fiber web layer and flows along the surface. Hydrophilic coating compositions can be difficult to reach. In addition, the hydrophilic coating layer may not be properly formed on the outer surface of the nanofiber to reach inside. This improves the penetration of the hydrophilic coating composition into the fibrous web layer, allows the penetrated hydrophilic coating composition to wet the outer surface of the nanofibers, and allows the hydrophilic coating composition to be quickly dried and coated on the nanofibers before flowing down. The hydrophilic coating composition may further include a wettability improving agent.

The wettability improving agent may be used without limitation when it is a component that can improve the wettability of the hydrophilic solution of the hydrophobic nanofiber outer surface and can be easily vaporized and dissolved in the hydrophilic coating composition. For example, the wettability improving agent may be at least one component selected from the group consisting of isopropyl alcohol, ethyl alcohol, and methyl alcohol, and more preferably, the shrinkage phenomenon of the fibrous web due to vaporization of the wettability improving agent and thus the first designed It is preferable to use isopropyl alcohol to prevent the pore structure of the fibrous web. In addition, the wettability improving agent may be included in an amount of 1,000 to 20,000 parts by weight, preferably 5,000 to 15,000 parts by weight, based on 100 parts by weight of polyvinyl alcohol provided in the hydrophilic coating composition. For example, the wettability improving agent may be included in an amount of 5,000 parts by weight based on 100 parts by weight of polyvinyl alcohol. If the wettability improving agent is provided in less than 1,000 parts by weight, the wettability improvement of the nanofibers may be poor, so that the formation of the hydrophilic coating layer may not be smooth, and the hydrophilic coating layer may be frequently peeled off. In addition, when the wettability improving material is included in an amount exceeding 20,000 parts by weight, the degree of wettability improvement may be insignificant, and the concentration of the polyvinyl alcohol and the crosslinking agent included in the hydrophilic coating composition may be low, thereby preventing the formation of the hydrophilic coating layer.

On the other hand, when the hydrophilic coating layer is coated on the nanofibers to a predetermined thickness or more, the average diameter and / or porosity of the nanofiber web may be reduced due to the coated nanofibers, rather the water permeability and filtration efficiency may be reduced. If there is a concern and the coating is less than a certain thickness, there is a fear that the filtration efficiency is significantly lowered, the hydrophilic coating layer may be coated in a certain thickness range. Accordingly, the hydrophilic coating layer according to the present invention may be coated with a thickness of 5 to 20%, preferably 8 to 18% of the average diameter of the nanofibers. For example, the hydrophilic coating layer may be coated with a thickness of 12% of the average diameter of the nanofibers. If the hydrophilic coating layer is formed to a thickness less than 5% of the average diameter of the nanofibers, the hydrophilic coating layer is peeled off during the backwashing process under excessive pressure, and thus the filtration efficiency may not be exhibited at a desired level. When the thickness is formed, 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.

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 for contaminants may not be good.

The nanofiber webs 111 and 112 may have a porosity of 40 to 90%, preferably 45 to 80%. For example, the nanofiber webs 111 and 112 have a porosity of 45%. Can be. If the porosity of the nanofiber webs 111 and 112 is less than 40%, the water permeability to the filtrate may be lowered. If the porosity exceeds 90%, the filtration efficiency of the filter media against contaminants may not be good. Can be.

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 the outside of the filter medium to expand in both directions. However, 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. 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. 3A, 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 coupled 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. 3B 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) laminating the fibrous web and the second support to produce a laminate; (3) a hydrophilic coating composition comprising at least a portion of the nanofiber outer surface of the fibrous web provided in the laminate, a hydrophilic polymer compound having at least one functional group selected from a hydroxy group and a carboxyl group and a crosslinking agent having at least one sulfone group Forming a hydrophilic coating layer through; And (4) arranging and stacking laminates each including a hydrophilic coating layer on both sides 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 may be included in 5 to 30% by weight, preferably 8 to 20% by weight in the spinning solution, for example, the fluorine-based compound may be included in 15% by weight in the spinning solution. If the fluorine-based compound is less than 5% by weight, it is difficult to form a fiber, and when spun, it is not spun into fibers but sprayed in droplets to form a film or spun, even though beads are formed and volatilization of the solvent is difficult. Pore blocking may occur in the calendaring process described below. 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.

Next, step (2) of manufacturing the laminate by laminating the fibrous web and the second support will be described.

When the second support is made of a low melting composite fiber, binding through the heat fusion of the fibrous 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 fibrous 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 fibrous web without being included since it may dissolve during water treatment and cause environmentally negative problems.

Next, a hydrophilic coating composition comprising a hydrophilic polymer compound having at least one functional group selected from a hydroxy group and a carboxy group and a crosslinking agent having at least one sulfone group on at least a part of the nanofiber outer surface of the fibrous web provided in the laminate. It describes the step (3) to form a hydrophilic coating layer through.

According to an embodiment of the present invention, the step (3) comprises the steps of (3-1) treating the hydrophilic coating composition to form a hydrophilic coating layer on the laminate; And (3-2) removing the hydrophilic coating layer formed on the second support by washing the laminate on which the hydrophilic coating layer is formed.

In the step (3-1), the hydrophilic coating composition may include a solvent, a hydrophilic polymer compound and a crosslinking agent.

The solvent is purified water, ethanol, methanol, ethylene glycol, acetic acid, hexene, cyclohexene, cyclopentane, diisobutylene, 1-pentene, carbon disulfide, carbon tetrachloride, 1-chlorobutene, 1-chloropentene, o- Xylene, diisopropyl ether, 2-chloropropane, toluene, diethyl ether, diethyl sulfide, dichloromethane, 4-methyl-2-propane, tetrahydrofuran, 1,2-dichloroethane, 2-butanone , 1-nitropropane, acetone, 1,4-dioxane, ethyl acetate, methyl acetate, 1-pentanol, dimethyl sulfoxide, aniline, nitromethane, acetonitrile, pyridine, 2-butoxyethanol, 1-propanol and It is preferable to include one or more solvents selected from the group consisting of 2-propanol, but is not limited thereto. Known solvents that do not affect the mixing and physical properties of the hydrophilic coating composition may be used.

In addition, the hydrophilic polymer compound may be included in 0.3 to 1.5 parts by weight, preferably 0.5 to 1.3 parts by weight with respect to 100 parts by weight of the solvent. For example, the hydrophilic polymer compound may be included in an amount of 1 part by weight based on 100 parts by weight of the solvent.

On the other hand, the hydrophilic coating layer may be formed by crosslinking the hydrophilic polymer compound through a crosslinking agent.

The crosslinking agent may include sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid) as described above, and includes sulfosuccinic acid and poly (styrenesulfonic acid-maleic acid). When added to the solvent at once, aggregation between crosslinking agents may occur, so that the first solvent and the second solvent are used as the solvent, and sulfosuccinic acid is added to the first solvent together with the hydrophilic polymer compound. The poly (styrenesulfonic acid-maleic acid) may be added to the second solvent to prepare a solution, and then the first solution prepared through the first solvent and the second solution prepared through the second solvent may be mixed. . In this case, the first solvent and the second solvent may be the same type of solvent, may be different solvents.

In addition, the step (3-2) is a step of removing the hydrophilic coating layer formed on the second support by washing the laminate, the washing process can only remove the hydrophilic coating layer formed on the second support, the first support It is possible to further improve the adhesive force with the.

Next, a step (4) of placing and stacking a laminate including a hydrophilic coating layer on each side of the first support such that the second support contacts the first support will be described.

In the step (4), the nanofiber web and the second support are laminated on both surfaces of the first support, respectively, to apply the heat and pressure to one or more of the first support and the second support by fusion and lamination. 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 in the nanofiber web to flow out through the support on 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 media according to the present invention can minimize the shape, structural deformation, and damage of the filter media during the water treatment operation, and have a high flow rate because the flow path is smoothly secured. In addition, due to the excellent durability of the filter media even at high pressure applied during backwashing, it has an extended service life, and the hydrophilic component is uniformly coated on the surface to show excellent water permeability and chemical resistance, and easy to control contamination. As the filtration performance for cation-containing contaminants such as cationic compounds is excellent, it can be variously applied 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>

(1) Preparation of hydrophilic coating composition

A mixed solution was prepared by dissolving 10 g of polyvinyl alcohol (Kuraray Co., PVA217) having a polymerization degree of 1,800 and a saponification degree of 88% with a hydrophilic polymer compound in 500 g of ultrapure water as a first solvent at a temperature of 80 hours using a magnetic bar. After lowering the mixed solution to room temperature, 1.5 g of sulfosuccinic acid (Aldrich, SSA) was mixed with the first crosslinking agent, and dissolved at room temperature for 12 hours to prepare a first solution.

A second solution was prepared by dissolving 10 g of polystyrene sulfonic acid comaleic acid (Aldrich, PSSA-MA) as a second crosslinking agent in 500 g of ultrapure water as a second solvent using a magnetic bar at room temperature for 6 hours. Thereafter, the first solution and the second solution were mixed and dissolved for 12 hours to prepare a coating solution. Thereafter, isopropyl alcohol (Duksan Chemical, IPA) as a wetting agent was added to the coating solution, such as 500 g of ultrapure water by weight, and mixed for 2 hours to prepare a hydrophilic coating composition.

(2) filter media manufacture

In order to prepare the 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 a weight ratio of dimethylacetamide and acetone was mixed at 70:30. The solution was dissolved to prepare a mixed solution. 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 is 30 ℃, humidity was maintained at 50%, the distance between the collector and the spinning nozzle 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. As a second support, 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 primary part and a polypropylene core part is disposed on one side of the nanofiber web. After the application, heat and pressure were applied at a temperature of 140 ° C. and 1 kgf / cm 2 to carry out a calendaring process to laminate the second support and the nanofiber web to prepare a laminate.

Thereafter, the laminate prepared in the hydrophilic coating composition prepared above was dried at a temperature of 100 for 5 minutes in a dryer after impregnation through a dipping process. Curing reaction proceeds with drying to form a hydrophilic coating layer on the laminate.

5 L of pure water was removed to remove the hydrophilic coating layer formed on the second support, and two laminates from which the hydrophilic coating layer formed on the second support was removed were placed on both sides of the first support such that the second support was brought into 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 ℃.

<Examples 2 to 19 and Comparative Examples 1 to 3>

Manufactured in the same manner as in Example 1, the polymerization degree of the hydrophilic polymer compound, saponification degree, the content of the crosslinking agent, the weight ratio between the crosslinking agent and the content of the wettability improving agent, and the like as shown in Table 1 to Table 4, The same filter medium was prepared.

Experimental Example

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

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. Evaluation of cation filtration efficiency

For the filter unit implemented with each filter medium prepared in Examples and Comparative Examples, the filtration efficiency of Na ⁺ was measured through ion chromatography analysis.

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  Evaluation of Filtration Efficiency of Post Cations

For the filter unit implemented with each filter medium prepared in Examples and Comparative Examples, after performing the backwash, the filtration efficiency of Na ⁺ was measured through ion chromatography analysis.

division Example
One Example
2 Example
3 Example
4 Example
5 Example
6 Hydrophilic
Coating Composition PVA Degree of polymerization 1800 300 1500 2500 1800 1800 Degree of safty (%) 88 88 88 88 83 86 Crosslinking agent Content (parts by weight) 115 115 115 115 115 115 1st, 2nd
Crosslinking agent weight ratio 1: 6.7 1: 6.7 1: 6.7 1: 6.7 1: 6.7 1: 6.7 Wetting improver Content (parts by weight) 5000 5000 5000 5000 5000 5000 Whether the first support is included ○ ○ ○ ○ ○ ○ Whether to include the second support ○ ○ ○ ○ ○ ○ Relative Water Permeability (%) 100 105 102 74 104 101 Cationic Filtration Efficiency (%) 95 86 94 97 84 94 Backwash Durability ○ × ○ ○ × ○ Cationic filtration efficiency (%) after backwash 95 69 94 96 66 94

division Example
7 Example
8 Example
9 Example
10 Example
11 Example
12 Hydrophilic
Coating Composition PVA Degree of polymerization 1800 1800 1800 1800 1800 1800 Degree of safty (%) 89 92 88 88 88 88 Crosslinking agent Content (parts by weight) 115 115 70 90 140 160 1st, 2nd
Crosslinking agent weight ratio 1: 6.7 1: 6.7 1: 6.7 1: 6.7 1: 6.7 1: 6.7 Wetting improver Content (parts by weight) 5000 5000 5000 5000 5000 5000 Whether the first support is included ○ ○ ○ ○ ○ ○ Whether to include the second support ○ ○ ○ ○ ○ ○ Relative Water Permeability (%) 99 - 107 103 91 72 Cationic Filtration Efficiency (%) 96 - 87 93 96 97 Backwash Durability ○ - × ○ ○ ○ Cationic filtration efficiency (%) after backwash 96 - 63 93 96 97

division Example
13 Example
14 Example
15 Example
16 Example
17 Example
18 Hydrophilic
Coating Composition PVA Degree of polymerization 1800 1800 1800 1800 1800 1800 Degree of safty (%) 88 88 88 88 88 88 Crosslinking agent Content (parts by weight) 115 115 115 115 115 115 1st, 2nd
Crosslinking agent weight ratio 1: 1 1: 5 1: 8 1:12 1: 6.7 1: 6.7 Wetting improver Content (parts by weight) 5000 5000 5000 5000 500 25000 Whether the first support is included ○ ○ ○ ○ ○ ○ Whether to include the second support ○ ○ ○ ○ ○ ○ Relative Water Permeability (%) 86 92 83 75 73 83 Cationic Filtration Efficiency (%) 84 91 96 98 93 78 Backwash Durability ○ ○ ○ ○ ○ × Cationic filtration efficiency (%) after backwash 84 91 96 98 93 61

division Comparative example
One Comparative example
2 Comparative example
3 Hydrophilic
Coating Composition PVA Degree of polymerization - 1800 1800 Degree of safty (%) - 88 88 Crosslinking agent Content (parts by weight) - 115 115 1st, 2nd
Crosslinking agent weight ratio - 1: 6.7 1: 6.7 Wetting improver Content (parts by weight) - 5000 5000 Whether the first support is included ○ ○ × Whether to include the second support ○ × ○ Relative Water Permeability (%) 22 118 112 Cationic Filtration Efficiency (%) 11 86 83 Backwash Durability ○ × × Cationic filtration efficiency (%) after backwash 10 51 39

 As can be seen in Tables 1 to 4, Examples 1, 3, 6, and 7 satisfying all of the degree of polymerization, saponification degree, crosslinking agent, weight ratio between crosslinking agents, and wettability improving agent of the hydrophilic polymer compound according to the present invention. , Water permeability, filtration efficiency, inverse compared to Examples 2, 4, 5, 8, 9, 12, 13, 16-18, and Comparative Examples 1-3, where 10, 11, 14, and 15 are missing any of these. Both washing durability and filtration efficiency were excellent at the same time.

On the other hand, in Example 8, since the degree of saponification is excessive, the coating layer is not formed, and thus physical properties cannot be measured.

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 same scope. Other embodiments may be easily proposed by changing, deleting, adding, etc., but this will also be within the scope 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;
On the upper and lower portions of the first support, respectively, nanofibers having a three-dimensional network structure and at least a portion of an outer surface of the nanofibers, a hydrophilic polymer compound of polyvinyl alcohol and 100 parts by weight of the hydrophilic polymer compound Nanofiber web comprising a hydrophilic coating layer formed through a hydrophilic coating composition comprising 80 to 150 parts by weight of a crosslinking agent having at least one sulfone group; And
And a second support having a plurality of pores interposed between the first support and the nanofiber web, respectively. The method of claim 1,
The hydrophilic polymer compound is a filter medium is a polyvinyl alcohol of 500 to 2000 degree of polymerization and 85 to 90% saponification. The method of claim 1,
The crosslinking agent comprises a sulfosuccinic acid (sulfosuccinic acid) and poly (styrenesulfonic acid-maleic acid) in a weight ratio of 1: 3 to 10. The method of claim 1,
The hydrophilic coating layer is a filter medium formed by crosslinking the hydrophilic polymer compound through a crosslinking agent. delete The method of claim 1,
The hydrophilic coating composition is filter medium further comprising a wettability improver in a weight part of 1,000 ~ 20,000 with respect to 100 parts by weight of the hydrophilic polymer compound. The method of claim 6,
The wetting property improver is isopropyl alcohol filter media. The method of claim 1,
The hydrophilic coating layer is filter media formed to a thickness of 5 to 20% of the average diameter of the nanofibers. The method of claim 1,
The nanofiber web has an average pore size of 0.1 ~ 3㎛, pore size 40 ~ 90% filter media. The method of claim 1,
The nanofiber has an average diameter of 50 ~ 450 nm 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. The method of claim 1, wherein the first support is
A low melting point component of the first composite fiber and a low melting point component of the second composite fiber having a first composite fiber including at least a portion of the low melting point component exposed to an outer surface, including a support component and a low melting point component Filter media in which the first support and the second support are bound by interfusion. 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 to 800 g / ㎡. The method of claim 1, wherein the second support,
A filter comprising a second composite fiber disposed such that at least a portion of the low melting point component is exposed to an outer surface, including a support component and a low melting point component, wherein the low melting point component of the second composite fiber is fused to the nanofiber web Media. 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) laminating the fibrous web and the second support to produce a laminate;
(3) 80 to 150 a crosslinking agent having at least a part of the nanofiber outer surface of the fibrous web provided in the laminate, a hydrophilic polymer compound which is polyvinyl alcohol and at least one sulfone group based on 100 parts by weight of the hydrophilic polymer compound Forming a hydrophilic coating layer through a hydrophilic coating composition comprising parts by weight; And
(4) arranging and stacking laminates each including a hydrophilic coating layer on both sides of the first support such that the second support contacts the first support. The method of claim 16, wherein step (3),
(3-1) treating the hydrophilic coating composition to form a hydrophilic coating layer on the laminate; And
(3-2) removing the hydrophilic coating layer formed on the second support by washing the laminate on which the hydrophilic coating layer was formed. The filter medium according to any one of claims 1 to 4, 6 to 15; 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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