KR20180018932A - Filter media and Filter unit comprising the same - Google Patents

Abstract

A filter medium is provided. The filter medium according to one embodiment of the present invention includes: a first filter medium and a second filter medium; and a first support interposed between the first and second filter media and having a plurality of holes passing through a surface opposed to the first and second filter media in order to increase a flow passage and minimize water permeation resistance. Accordingly, the present invention is able to maintain the shape of a membrane even at a high pressure applied during filtration and/or backwashing, and the flow passage can be smoothly formed to prevent the flow passage from being reduced and to minimize the damage to the membrane. Further, as the permeation resistance of a filtering solution or washing liquid flowing through an inner flow passage of the membrane is minimized, the present invention is able to obtain a further increased flow passage or achieve backwashing efficiency, thus being able to be variously applied in the field of water treatment.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter medium,

The present invention relates to a filter medium, and more particularly, to a filtration fluid passing through a filter medium or a backwashing efficiency by minimizing the permeation resistance of a washing liquid or air injected into the filter medium during backwashing And also to a filter unit including the same. [0002] The present invention relates to a filter medium having excellent durability and mechanical strength capable of withstanding high pressure due to backwashing, and a filter unit including the filter medium.

The separation membrane can be classified into a microfiltration membrane (MF), an ultrafiltration membrane (UF), a nanofiltration membrane (NF), or a reverse osmosis membrane (RO) depending on the pore size.

Although the separation membranes have different usages and pore size differences, they have a common feature in that they are in the form of a filtration medium or a porous polymer filtration medium formed from fibers or a composite membrane thereof.

The porous polymer filter medium may be formed by forming pores formed in a polymer membrane or a polymer hollow fiber by sintering the pore former through a separate pore former contained in the tank solution or by dissolving the pore former in an external coagulating solution It is common. On the contrary, the filter medium formed from the fibers is generally manufactured by accumulating the manufactured short fibers and then applying heat / pressure or the like, or applying heat / pressure or the like simultaneously with the spinning.

Typical examples of the filtration media formed from the fibers are nonwoven fabric. In general, the pores of the nonwoven fabric are controlled by the diameter of the short fibers, the basis weight of the medium, and the like. However, since the diameter of the short fibers included in the general nonwoven fabric is in the unit of microns, there is a limitation in realizing a separation membrane having a fine and uniform pore structure only by controlling the diameter and basis weight of the fibers. Accordingly, It is difficult to realize a separation membrane such as an ultrafiltration membrane or a nano separation membrane for filtration.

A method designed to solve this problem is a separation membrane produced through microfibers having a fiber diameter of nanometer. However, the microfine fiber having a diameter of nanometer unit is difficult to be manufactured by only one spinning process by a fiber spinning process such as a general wet spinning process, and it is necessary to elute the sea component separately after radiating to sea chart yarn, There is a problem that it is troublesome to work, the cost is increased, and the production time is extended. Recently, there has been a tendency to manufacture a large number of filter media formed from fibers by directly spinning fibers having a diameter of nanometer unit through electrospinning.

However, the filtration media formed of nano-unit diameter fibers have a problem that the mechanical strength is so weak that they can not withstand the pressure applied to the filter media during filtration or the larger pressure applied during backwashing, resulting in tearing or damage. Further, even when a separate supporting member is further provided to solve this problem, when the filter medium is compressed by the applied pressure, the flow path inside the filter medium is closed, so that the pressure applied to the filter medium is further increased and the flow rate is significantly reduced.

Further, even in the backwashing process, the flow path formed in the filter medium is insufficient, so that backwashing can not be smoothly performed, and the filter material can not withstand the applied pressure, resulting in a problem that the filter material is damaged.

Therefore, it is urgently required to develop a filter material having mechanical strength so as to prevent the flow rate from being lowered and to minimize the damage of the filter material by sufficiently securing the flow path even when high pressure is applied during filtration and / or backwashing.

Patent Registration No. 10-0871440

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a membrane filtration apparatus capable of securing a channel even at high pressure applied in a filtration and / or backwashing process, And an object of the present invention is to provide a filter medium capable of exhibiting excellent flow rates.

Another object of the present invention is to provide a filter material in which the shape of the membrane is maintained even at a high pressure applied in the filtration and / or backwashing process, and the membrane damage can be minimized.

It is a further object of the present invention to provide a filter unit and a filter module which can be applied variously in the field of water treatment through a filter material having excellent water permeability and durability.

In order to solve the above-described problems, Second media; A first support interposed between the first and second filter media and having a plurality of holes penetrating the first filter media and the second filter media to increase the flow path and minimize water permeation resistance; And a filter medium.

According to an embodiment of the present invention, the first support may include at least one of a nonwoven fabric, a woven fabric and a knitted fabric, more preferably a nonwoven fabric.

The first support includes a first composite fiber including a support component and a low melting point component such that at least a part of the low melting point component is exposed on the outer surface, 1 and the second filter material, respectively, so that the first and second filter materials can be bonded to each other.

The basis weight of the first support may be 250 to 800 g / m 2, and the thickness of the first support may be 2 to 8 mm.

The hole may have a diameter of 5 to 150 mm.

In addition, the cross-sectional surface of the hole may be at least one of a closed curve including at least one side line segment and a closed curve line including no line segment.

In addition, any one or more of the first filter material and the second filter material may include a nanofiber web having a three-dimensional network structure.

In addition, the nanofiber web may have an average pore size of 0.1 to 5 μm and a porosity of 40 to 90%.

In addition, the nanofiber web may include nanofibers, and the average diameter of the nanofibers may be 50 to 450 nm.

The nanofiber web may include a nanofiber including a fluorine-based compound, and the fluorine-based compound may be at least one selected from the group consisting of polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (EPE), tetrafluoroethylene-ethylene copolymer (ETFE) Based compound, a chlorotrifluoroethylene-ethylene copolymer (ECTFE) -based compound, and a polyvinylidene fluoride (PVDF) -based compound.

In addition, the filter material may further include a second support provided on one side of the nanofiber web, and the second support may be disposed to face the first support. At this time, the second support may include at least one of a nonwoven fabric, a woven fabric and a knitted fabric, more preferably a nonwoven fabric. The basis weight of the second support may be 35 to 80 g / m 2, and the thickness may be 150 to 250 탆.

The second support includes a second composite fiber including a support component and a low melting point component such that at least a part of the low melting point component is exposed on the outer surface, and the low melting point component of the second composite fiber is a nano- The fibrous web and the first support.

The second support may include a hole penetrating the nanofiber web and the outer surface facing the first support. At this time, the average diameter of the holes provided in the second support body may be smaller than the average diameter of the holes provided in the first support body.

The filter media may be an ultrafiltration membrane.

The present invention also relates to a filter media according to the present invention; And a support frame for supporting the rim of the filter media, the filter having a flow path for allowing the untreated water to flow into the filter medium and allowing the filtrate to flow out to the outside.

Also, the present invention provides a filter module comprising a plurality of filter units according to the present invention spaced apart at a predetermined interval.

According to the present invention, the filter material has mechanical strength capable of perfectly maintaining the shape of the membrane and the pore structure even at a high pressure applied at the time of filtration and / or backwashing, smooth flow path formation is prevented, Damage can be minimized. Further, as the permeation resistance of the filtrate or washing liquid flowing through the inner channel of the filter medium is minimized, a further increased flow rate can be obtained and the backwashing efficiency can be achieved. In addition, since the pressure applied to the filter material can be relatively reduced due to the reduced permeation resistance, it can be applied to various applications in the water treatment field because it can exhibit improved durability.

1 is a sectional view of a filter medium according to an embodiment of the present invention,
Figures 2A-2D illustrate various embodiments of a cross-sectional shape of a hole formed in a first support included in an embodiment of the present invention,
FIG. 3 is a view illustrating a circumscribed circle and an inscribed circle based on a cross-section of a hole formed in the first support according to FIG.
4A and 4B are a cross-sectional view and an exploded perspective view of a filter media according to an embodiment of the present invention,
5 is an exploded perspective view of a filter material according to an embodiment of the present invention,
FIGS. 6A and 6B are a schematic view showing a filtration flow based on a perspective view and a cross-sectional view of a boundary line X-X 'of a filter module having filter media according to FIG.
FIG. 7 is a schematic view showing a filtration flow based on a cross-sectional view of a boundary line X-X 'by applying the filter filter material according to FIG. 5 to the filter module of FIG. 6A;
8 is an exploded perspective view of a cylindrical filter module according to an embodiment of the present invention,
FIG. 9 is a scanning electron microscope photograph of the cross section of the first filter medium and the second filter medium included in one embodiment of the present invention, and
FIGS. 10A to 10D are diagrams of a nanofiber web of filter media included in an embodiment of the present invention, wherein FIG. 10A is a photograph of a surface electron microscope of a nanofiber web, FIG. 10B is a cross- FIG. 10C is a graph of the fineness distribution of the nanofibers provided in the nanofiber web, and FIG. 10D is a graph of the pore size distribution of the nanofiber web.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

1, a filter material 1000 according to an embodiment of the present invention includes a first filter material 101, a second filter material 102, and a first support body 200 provided between the filter media 101 and 102 ).

First, the first support 200 will be described.

The first support member 200 serves to complement mechanical strength of the first and second filter members 101 and 102 to prevent damage to the filter member and to form a flow path. 1, the filtered supernatant is filtered from the outside of the filter media 101 and 102 to the inside of the filter media, or is filtered in the opposite direction to the filter media 1000, The filtration process may be performed by flowing into the first filter medium 101 and the second filter medium 102.

The reason that the filter medium 1000 having such a filtration path is subjected to a pressure for filtration means that a force for compressing the filter medium from the outside toward the inside or a force for expanding the inside from the outside toward the outside is applied to the filter medium 1000, If the mechanical strength of the first filter medium 101 and the second filter medium 102 is low at this time, the pressure of the filter medium may be damaged by the applied pressure, and the filtration efficiency may be lowered. In addition, when the filter media is compressed from the outside toward the inside of the filter media, the flow passage through which the filtrate to be filtered in the direction of the inside of the filter media is reduced or blocked, so that a larger differential pressure is applied to the filter media, Can be degraded.

On the other hand, when a force for bi-directionally expanding from the inside of the filter media toward the filter medium is applied, the interface between the filter media 101 and 102 and the first support 200 can be separated, Can be reduced. Further, when the resistance of the fluid flowing in the flow path inside the filter is large, the above-described problem may occur more frequently and significantly.

Accordingly, the first support member 200 provided in the filter media 1000 according to an embodiment of the present invention may include a first support member 101 and a second support member 102 to increase the flow path and minimize the water permeation resistance. And has a plurality of holes (P) passing through respective facing surfaces. The holes P provided in the first support body 200 provide a larger flow path for the filtered liquid passing through the first filter media 101 and the second filter media 102 or the passing through liquid for passing therethrough, And the pressure applied to the interior of the filter media can also be reduced. Therefore, even when a larger filtration pressure and / or a backwashing pressure is applied to the filter filter material, the pressure applied to the filter filter material can be further reduced, the damage of the filter material including the filter material is minimized, And there is an advantage that a further increased flow rate can be obtained.

The cross section of the hole P may be a shape of at least one of a closed curve including at least one side line segment and a closed curve line including no line side. Concretely, a closed curve including at least one line segment means a closed curve (eg, a semi-circle, a fan shape, etc.) formed by at least one side line and a curved line, or a polygon (eg, a triangle, a rectangle, a pentagon, etc.). In addition, a closed curve not including a line segment means a closed curve formed by a curve, for example, a circle, an ellipse, and the like. 2A to 2C, the first support 201 of FIG. 2A includes a hole P ₃ having a cross-sectional shape of a closed curve not including an elliptical line segment, and the first support 201 of FIG. 202 includes a hole P ₄ having a cross-sectional shape, which is a closed curve composed of two line segments parallel to each other and two curved lines connecting opposite end points of the line segments. In addition, the first support 203 of Figure 2c includes a rectangular shaped hole (P _5).

The cross-sectional surfaces of the plurality of holes provided in the first support may have at least one or more shapes. Specifically, the cross-sections may have the same shape as shown in Figs. 2A to 2C. Alternatively, Shape (P ₆ , P ₇ ).

The diameter of the hole P can be changed in consideration of the filtration pressure (or the backwashing pressure) applied to the filter media, the mechanical strength of the first support, the viscosity of the overpurified liquid, etc. Accordingly, It does not specify. However, if the diameter of the hole is less than 10 mm, for example, the effect of minimizing the pressure applied to the filter medium through the hole, forming the flow path, reducing the flow resistance of the fluid may be insignificant. If the diameter of the hole exceeds 150 mm, it may be advantageous to obtain a larger flow rate, but the mechanical strength of the first support member is weakened and the first or second filter member facing the hole-formed portion is not supported Thus, damage to the filter media may occur.

In addition, the plurality of holes P may include holes having the same diameter or a diameter different from a part of the plurality of holes P. [

The interval between the holes P may be changed in consideration of the filtration pressure (or the backwashing pressure) applied to the filter media, the mechanical strength of the first support, the viscosity of the overpurified liquid, etc. For example, Lt; / RTI > The interval between the holes P means the shortest distance from the outer circumference of the hole to the outer circumference of the adjacent hole.

The hole P may be formed to have a modified cross-section so as to reduce the fluid flow resistance to obtain an improved flow rate. At this time, as shown in FIG. 3, the hole P ₃ may be formed by the inscribed circle diameter 2r of the hole, A specific value calculated by the ratio of the circumscribed circumferential length of the hole to the circumferential length of the hole and / or the first apostrophe having a specific value calculated by the ratio to the diameter (2R) can satisfy the second variance degree.

Further, the first support 200 is not particularly limited as long as it serves as a support for the separation membrane, but it may preferably be a fabric, a knitted fabric or a nonwoven fabric. The fabric means that the fibers included in the fabric have longitudinal and lateral directions, and the specific structure may be plain weave, twill weave, etc., and the density of warp and weft yarn is not particularly limited. 2B, the first supporting body 202 may be formed by a yarn 202a which is a warped knitted fabric. In this case, the yarn 202a may be a warp knitted fabric, have. As shown in FIG. 2A, the first support 201 may be a nonwoven fabric having no longitudinal or transverse directionality on the fibers 201a, 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, , Needle punching nonwoven fabric or melt blown nonwoven fabric may be used. When the first support is a nonwoven fabric, the pore size, the porosity, the basis weight and the like may vary depending on the desired water permeability, filtration efficiency, and mechanical strength, so that the present invention is not particularly limited thereto.

In addition, the material of the first support 200 is not limited if it is used as a support of a separation membrane. By way of non-limiting example, synthetic polymer components selected from the group consisting of polyester based, polyurethane based, polyolefin based and polyamide based; Or a natural polymer component including a cellulose system may be used. However, if the first support has a brittle physical property, it may be difficult to expect a desired bonding strength in the process of laminating the first support to the nano-web or a second support, which will be described later. The surface may be macroscopically roughened while forming the porosity, and the surface formed by the fibers, such as nonwoven fabric, is not smooth due to the arrangement of the fibers, the fineness of the fibers, and the roughness It can be different. If the remaining portions are bonded while the portion not in contact with the interface between the two layers being bonded is present, delamination may be started due to the non-adhered portion. In order to solve this problem, it is necessary to carry out the lapping process while increasing the degree of close contact between the two layers by applying pressure in both layers. If the brittle physical property is strong, There is a limit in height, and when a larger pressure is applied, the support may be broken, so that the material of the first support may be flexible, may be made of a high-elongation material, and preferably, 1 The support 200 may be a polyolefin-based material.

Meanwhile, the first support 200 may include a low melting point component to bind to the filter media 101 and 102 without a separate adhesive or adhesive layer. When the first support 201 is made of the same material as the nonwoven fabric, it may be made of the first composite fiber 201a having a low melting point component. The first composite fiber 201a may include a support component and a low melting point component so that at least a part of the low melting point component is exposed on the outer surface. For example, a cis-core type conjugate fiber in which a support component forms a core portion and a low melting point component forms a sheath portion surrounding the core portion, and a side-by-side composite fiber having a low- Lt; / RTI > The low-melting-point component and the support component may be polyolefin-based in view of the flexibility and elongation of the support, as described above. For example, the support component may be polypropylene and the low-melting component may be polyethylene. The melting point of the low melting point component may be 60 to 180 ° C.

Further, the thickness of the first support 200 may be 2 to 8 mm, more preferably 2 to 5 mm, and still more preferably 3 to 5 mm. If the thickness is less than 2 mm, it may not exhibit sufficient mechanical strength to withstand frequent backwashing. Also, when the thickness exceeds 8 mm, the degree of integration of the filter material per unit volume of the module may be reduced when the filter material is implemented as a filter unit described below and a plurality of filter units are implemented by a limited space filter module.

The first support 200 may have a basis weight of 250 to 800 g / m 2, more preferably 350 to 600 g / m 2, while satisfying the thickness condition as described above. If the basis weight is 250 g / m < 2 >, it may be difficult to exhibit sufficient mechanical strength and adhesion to the filter material (or the second support described below) may be reduced. If the basis weight exceeds 800 g / The flow rate is decreased, and smooth backwashing due to an increase in differential pressure may be difficult.

When the first support 201 is formed of a fiber 201a such as a nonwoven fabric, the average diameter of the fibers 201a may be 5 to 50 占 퐉, and preferably 20 to 50 占 퐉. The first support body 200 may have an average pore size of 20 to 200 μm and a porosity of 50 to 90%. However, the present invention is not limited thereto, and the filtration process and / So as to exhibit the desired level of mechanical strength, and at the same time, the porosity and pore size can be such that the flow path can be smoothly formed even at high pressure.

Next, the first filter material 101 and the second filter material 102 which are respectively disposed on both surfaces of the first support body 200 will be described.

The first filter material 101 and the second filter material 102 may be employed without limitation in the case of a separation membrane known in the water treatment field. 4A and 4B, the filter media 101 and 102 included in one embodiment of the present invention further include second support members 121 and 122 such that the nanofiber webs 111 and 112 are disposed on the second support members 121 and 122 As shown in FIG. At this time, the nanofiber webs 111 and 112 may have a three-dimensional network structure.

The nanofiber webs 111 and 112 may be employed without limitation in the nanofiber web known in the water treatment field. Preferably, the nanofiber webs 111 and 112 may be a three-dimensional network structure in which one strand or multiple strands of nanofibers are randomly and three-dimensionally stacked (see FIG. 10A).

The nanofibers forming the nanofiber webs 111 and 112 may be formed of known fiber forming components. However, in order to exhibit excellent chemical resistance and heat resistance, a fluorine-based compound may be contained as a fiber-forming component, so that even if the water to be treated is a strong acid / strong base solution or a solution having a high temperature, And it has an advantage of securing the filtration efficiency / flow rate and having a long use period. The fluorine-based compound may be used without limitation in the case of a known fluorine-based compound that can be prepared as a nanofiber. Examples of the fluorine-based compound include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinylether copolymer Tetrafluoroethylene-hexafluoropropylene copolymer (PEP), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (EPE) (ETFE), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), and polyvinylidene fluoride (PVDF) More preferably, the production cost is low and mass production of nanofibers through electrospinning is easy, and the mechanical strength and chemical resistance are excellent In one aspect may be a polyvinylidene fluoride (PVDF). When the nanofiber includes PVDF as a fiber forming component, the PVDF may have a weight average molecular weight of 10,000 to 1,000,000, preferably 300,000 to 600,000, but is not limited thereto.

The nanofibers may have an average diameter of 0.05 to 1 占 퐉 and an aspect ratio of 1,000 to 100,000, but the present invention is not limited thereto. For example, the nanofibers provided in the nanofiber webs 111 and 112 may include a first nanofiber group having a diameter of 0.1 to 0.2 μm, a second nanofiber group having a diameter of 0.2 to 0.3 μm and a second nanofiber group having a diameter of 0.3 to 0.4 μm 3 nanofibers can be included in the amount of 35 wt%, 53 wt%, and 12 wt%, respectively, based on the total weight of the nanofiber web 111.

The thickness of the nanofibrous webs 111 and 112 may be 0.5 to 200 mu m, for example, 20 mu m. The porosity of the nanofiber webs 111 and 112 may be 40 to 90%, and more preferably 60 to 90%. In addition, the average pore diameter may be 0.1 to 5 占 퐉, more preferably 0.1 to 3 占 퐉, and may be 0.25 占 퐉, for example. The basis weight of the nanofiber webs 111 and 112 may be 0.05 to 20 g / m 2, and may be 10 g / m 2, for example, but is not limited thereto and may be appropriately changed in consideration of the desired water permeability and filtration efficiency.

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

The nanofibers 111a and 112a forming the nanofiber webs 111 and 112 may be modified to increase hydrophilicity. For example, the hydrophilic coating layers 131 and 132 may be formed on at least a portion of the outer surfaces of the nanofibers 111a and 112a. ) May be further provided. If the nanofibers include a fluorine-based compound as described above, the fluorine-based compound has a very high hydrophobicity, and thus the flow rate is poor when the supernatant is a hydrophilic solution. For example, the hydrophilic coating layer may be formed on the surface of the hydrophobic nanofibers. The hydrophilic coating layer may be formed of a known hydrophilic polymer having a hydroxyl group, or the hydrophilic polymer may be crosslinked through a crosslinking agent . For example, the hydrophilic polymer may be a polyvinyl alcohol (PVA), an ethylenevinyl alcohol (EVOH), a sodium alginate, or the like, and most preferably a polyvinyl alcohol (PVA). The crosslinking agent may be used without limitation in the case of a known crosslinking agent having a functional group capable of crosslinking through a condensation reaction with a hydroxyl group of the hydrophilic polymer. For example, the functional group may be a hydroxyl group, a carboxyl group, or the like.

The hydrophilic coating layers 131 and 132 may be formed by cross-linking a polyvinyl alcohol (PVA) and a cross-linking agent including a carboxyl group to exhibit improved physical properties. The polyvinyl alcohol may have a degree of polymerization of 500 to 2000 and a degree of saponification of 85 to 90%. If the degree of polymerization of polyvinyl alcohol is excessively low, the formation of the hydrophilic coating layer may not be smooth or may easily occur even if it is formed, and the hydrophilic property may not be improved to the desired level. In addition, if the degree of polymerization is too high, the formation of the hydrophilic coating layer may be excessive, thereby changing the pore structure of the nanofiber web or closing the pores. Further, if the saponification degree is too low, it may be difficult to improve hydrophilicity.

The crosslinking agent may be a component containing a carboxyl group so as to be crosslinked with the polyvinyl alcohol described above. For example, the crosslinking agent may include at least one material selected from the group consisting of poly (acrylic acid-maleic acid), polyacrylic acid, and poly (styrenesulfonic acid-maleic acid). In addition, in order to coat the surface of the nanofibers with improved hydrophobicity so that coating / adhesion to the surface of the nanofibers and the pore structure of the nanofibrous webs 111 and 112 are not changed, the cross-linking agent is coated with at least three carboxyl groups Based crosslinking agent. If the crosslinking agent has less than three carboxyl groups, the coating layer is hardly formed on the surface of the hydrophobic nanofibers, and even if it is formed, the adhesion force is very weak and can be easily peeled off. For example, the crosslinking agent having three or more carboxyl groups may be poly (acrylic acid-maleic acid).

The hydrophilic coating layer may be formed by crosslinking 2 to 20 parts by weight of a crosslinking agent containing a carboxyl group per 100 parts by weight of the polyvinyl alcohol. If the amount of the crosslinking agent is less than 2 parts by weight, the formation of the hydrophilic coating layer may be deteriorated and the chemical resistance and mechanical strength may be lowered. If the cross-linking agent is present in excess of 20 parts by weight, the pore may be reduced due to the coating layer, and the flow rate may be lowered.

On the other hand, the hydrophilic coating layer may be formed on part or all of the outer surface of the nanofiber. At this time, the hydrophilic coating layer may be coated with nanofibers such that the hydrophilic coating layer contains 0.1 to 2 g per unit area (m2) of the nanofiber web.

As described above, the wetting angle of the surface of the nanofibrous web 111, 112 modified to have the hydrophilic coating layer may be 30 degrees or less, more preferably 20 degrees or less, still more preferably 12 degrees or less, 5 ° or less, thereby providing an advantage of securing an improved flow rate despite the fact that the fiber web is embodied as a nanofiber that is hydrophobic in terms of material.

The second supports 121 and 122 support the nanofibers webs 111 and 112 and increase the bonding force of the layers provided in the filter media.

The second support members 121 and 122 are not particularly limited as long as they serve as a support for the filter media, but they may preferably be woven, knitted or nonwoven fabric. The fabric means that the fibers included in the fabric have longitudinal and lateral directions, and the specific structure may be plain weave, twill weave, etc., and the density of warp and weft yarn is not particularly limited. The knitted fabric may be a known knitted fabric, and may be a knitted fabric, a knitted fabric, or the like, but is not particularly limited thereto. The nonwoven fabric means that the fibers are not oriented in the longitudinal and transverse directions. The nonwoven fabric 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 spunless nonwoven fabric, a needle punching nonwoven fabric or a meltblown A non-woven fabric manufactured by the above-mentioned method can be used. Preferably, the second support 121, 122 may be a nonwoven fabric.

The fibers forming the second support bodies 121 and 122 may have an average diameter of 5 to 30 mu m. The thickness of the second support bodies 121 and 122 may be 100 to 400 탆, more preferably 150 to 400 탆, still more preferably 150 to 250 탆, for example, 200 탆 .

The second support bodies 121 and 122 may have an average pore size of 20 to 100 μm and a porosity of 50 to 90%. However, the present invention is not limited to this, and it may be possible to support the nanofiber webs 111 and 122 to be described later to develop a desired level of mechanical strength and to prevent the flow of the filtrate flowing through the nanofiber webs 111 and 122 Porosity, and pore size.

The basis weight of the second support bodies 121 and 122 may be 10 to 200 g / m 2, more preferably 35 to 200 g / m 2, and still more preferably 35 to 80 g / m 2. , And 40 g / m < 2 >. If the basis weight is less than 10 g / m < 2 >, the amount of the fibers forming the second support distributed at the interface formed with the nanofiber webs 111 and 112 described later may be small. It may not be possible to exhibit the desired level of bonding force due to a decrease in the bonding area. In addition, the nanofibrous web may not exhibit sufficient mechanical strength to support the nanofiber web, and adhesion with the first support may be reduced. If the basis weight exceeds 200 g / m < 2 >, it may be difficult to obtain the desired level of flow and the back pressure may increase, which may make it difficult to smoothly back wash.

The second support members 121 and 122 are not limited as far as they are used as a support for filter media. By way of non-limiting example, synthetic polymer components selected from the group consisting of polyester based, polyurethane based, polyolefin based and polyamide based; Or a natural polymer component including a cellulose system may be used.

However, the second support members 121 and 122 may be polyolefin-based polymer components for enhancing adhesion between the nanofiber webs 111 and 112 and the first support member 200. When the second supports 121 and 122 are made of the same material as the nonwoven fabric, they may be made of a second composite fiber including a low melting point component. The second composite fiber may include a support component and a low melting point component so that at least a part of the low melting point component is exposed on the external surface. For example, a cis-core type conjugate fiber in which a support component forms a core portion and a low melting point component forms a sheath portion surrounding the core portion, and a side-by-side composite fiber having a low- Lt; / RTI > The low-melting-point component and the support component may be polyolefin-based in view of the flexibility and elongation of the support, as described above. For example, the support component may be polypropylene and the low-melting component may be polyethylene. The melting point of the low melting point component may be 60 to 180 ° C.

If the first support 130 described above is embodied as a first composite fiber including a low melting point component to exhibit a further improved bonding strength with the second support 121 or 122, (Fig. 4A) due to fusion of the low-melting-point component of the first composite fiber and the low-melting-point components of the second composite fiber can be formed. At this time, the first composite fiber and the second composite fiber may be bonded to each other in terms of compatibility, and in order to facilitate the bonding process while preventing damages of the nanofiber web and the like due to heat / pressure applied in the interlaminar bonding process May be a material.

5, the second support bodies 123 and 124 include a plurality of holes Q ₁ and Q ₂ passing through the outer surfaces of the nanofiber webs 113 and 114 and the first support body 205, respectively, . At this time, the average diameter of the holes Q ₁ and Q ₂ provided in the second support bodies 123 and 124 may be smaller than the average diameter of the holes P 'provided in the first support body 205, no. The holes Q ₁ and Q ₂ provided in the second support bodies 123 and 124 are the same as those of the first support bodies 200, 201, 202, 203 and 204 described above.

The filter material 1000 described above can be manufactured by a manufacturing method described later, but is not limited thereto. The manufacturing method of the filter media to be described below will be described with reference to the filter media 1000 according to Figs. 4A and 4B.

The filter media 1000 according to the present invention comprises the steps of (1) fabricating a nanofiber web having a three-dimensional network shape formed of nanofibers containing a fluorine-based compound; (2) preparing a hydrophilic coating layer-forming composition on the nanofiber web to prepare a filter material comprising a nanofiber web on which a hydrophilic coating layer is formed; And (3) fabricating a filter material by providing a filter material on both surfaces of a first support having a plurality of through holes formed therein.

First, the step (1) will be described. This step is a step of forming a nanofiber web, and can be used without limitation in a method of forming a nanofiber web having a three-dimensional network shape with nanofibers. Preferably, the nanofiber web may be prepared by electrospinning a spinning solution containing a fluorine-based compound on a second support to form a nanofiber web.

The spinning liquid may be a fiber-forming component, for example, a fluorine-based compound and a solvent. The fluorine-based compound may be contained in the spinning solution in an amount of 5 to 30 wt%, preferably 8 to 20 wt%. If the fluorine-based compound is less than 5 wt%, it is difficult to form fibers, Even if the film is formed or spun, a large amount of beads are formed and the volatilization of the solvent is not performed well, so that the pores may be clogged in the calendering process described later. If the amount of the fluorine-based compound exceeds 30% by weight, the viscosity increases and the surface of the solution becomes solidified, which makes it difficult to spin for a long period of time.

The solvent may be any solvent that does not affect the radioactivity of the nanofibers described below without causing a precipitate while dissolving the fluorine-based compound as the fiber-forming component, but is preferably selected from γ-butyrolactone, cyclohexanone, 3 And at least one selected from the group consisting of hexanone, 3-heptanone, 3-octanone, N-methylpyrrolidone, dimethylacetamide, acetone dimethylsulfoxide and dimethylformamide. For example, the solvent may be a solvent for the mixing of dimethylacetamide and acetone.

The prepared spinning solution can be produced by a known electrospinning apparatus and method. For example, the electrospinning device may be an electrospinning device having a single spinning pack with one spinning nozzle or an electrospinning device with a plurality of single spinning packs or a spinning pack with multiple nozzles for mass production Also, Also, in the electrospinning method, wet spinning with dry spinning or external coagulation can be used, and there is no limitation with respect to the method.

The nanofiber web formed of nanofibers can be obtained when a spinning solution stirred in the electrospinning device is injected to electrospray on a collector, for example, paper. The specific conditions for the electrospinning are, for example, that the air pressure of the air injection nozzle provided in the nozzle of the spinning pack may be set in the range of 0.01 to 0.2 MPa. If the air pressure is less than 0.01 MPa, it can not contribute to the collection and accumulation. If the air pressure exceeds 0.2 MPa, the cone of the spinneret is hardened and the needle may be clogged and radiation trouble may occur. In addition, when the spinning solution is spinned, the injection rate of the spinning solution per nozzle may be 10 to 30 μl / min. The distance between the tip of the nozzle and the collector may be 10 to 30 cm. However, it is not limited to this, and it can be changed according to purpose.

Alternatively, the nanofiber web may be directly formed on the second support by directly electrospinning the nanofibers on the above-mentioned second support. The nanofibers accumulated / collected on the second support have a three-dimensional network structure, and heat and / or pressure is applied to retain the desired water permeability, filtration efficiency, porosity, pore size, And can be implemented as a nanofiber web having a three-dimensional network structure by being further added to the accumulated / collected nanofibers. As a specific method of applying the heat and / or the pressure, a known method may be adopted. As a non-limiting example, a conventional calendering process may be used, and the temperature of the applied heat may be 70-190 ° C. When the calendering process is carried out, it may be carried out a plurality of times, for example, a drying process for removing a part or all of the solvent and moisture remaining in the nanofibers through primary calendering, Secondary calendering can be performed for control and strength enhancement. At this time, the degree of heat and / or pressure applied in each calendering process may be the same or different.

On the other hand, when the second support is made of the low-melting-point conjugated fiber, the binding through the thermal fusion between the nanofibrous web and the second support can be promoted simultaneously through the calendering process.

Further, another hot melt powder or hot melt web may be further interposed to bind the second support and the nanofiber web. In this case, the applied heat may be 60 to 190 ° C, and the pressure may be 0.1 to 10 kgf / cm 2, but is not limited thereto. However, components such as hot melt powder, which are separately added for binding, are frequently melted in the laminating process between the support and the support and between the support and the nanofiber to frequently open the pores, thereby achieving the initial designed filter media flow rate It can not be done. In addition, it may dissolve in the water treatment process, which may cause environmental negative problems, so that it is preferable to bond the second support and the nanofiber web without preferably including them.

Next, in step (2) according to the present invention, a step of preparing a hydrophilic coating layer-forming filter material by treating the nanofiber web with a composition for forming a hydrophilic coating layer is performed.

Specifically, this step comprises: treating the nanofiber web with a composition for forming a hydrophilic coating layer; And thermally treating the hydrophilic coating layer forming composition to form a hydrophilic coating layer.

First, the hydrophilic coating layer-forming composition may include a hydrophilic component and a crosslinkable component, and may include, for example, polyvinyl alcohol, a crosslinking agent containing a carboxyl group, and a solvent for dissolving them, for example, water. The hydrophilic coating layer forming composition may include 2 to 20 parts by weight of a crosslinking agent and 1,000 to 100,000 parts by weight of a solvent, based on 100 parts by weight of polyvinyl alcohol.

On the other hand, when the nanofibers forming the nanofiber web include a fluorine-based compound, the coating layer may not be properly formed on the surface even if the hydrophilic coating layer forming composition is processed due to strong hydrophobicity. The hydrophilic coating layer-forming composition may further include a wettability improver so that the composition for forming a hydrophilic coating layer is well wetted on the outer surface of the nanofiber.

The wettability improver can be used without limitation as long as it can improve the wettability of the hydrophobic outer surface of the hydrophobic nanofiber to a hydrophilic solution and can be dissolved in the hydrophilic coating layer forming composition. For example, the wettability improver may be at least one component selected from the group consisting of isopropyl alcohol, ethyl alcohol and methyl alcohol. The wettability improver may be included in an amount of 1,000 to 100,000 parts by weight based on 100 parts by weight of polyvinyl alcohol in the composition for forming a hydrophilic coating layer. If the wettability improver is less than 1000 parts by weight, the improvement of the wettability of the nanofibers is insufficient, so that the hydrophilic coating layer may not be smoothly formed, and the hydrophilic coating layer may be frequently peeled off. If the wettability improver is contained in an amount of more than 100,000 parts by weight, the degree of wettability improvement may be insignificant, and the concentration of the polyvinyl alcohol and the cross-linking agent in the composition for forming a hydrophilic coating layer may be lowered and the formation of the hydrophilic coating layer may not be smooth.

Meanwhile, the hydrophilic coating layer may be formed by pretreating the wettability improver with the nanofiber web without treating the hydrophilic coating layer forming composition with a wettability improving agent, and then treating the hydrophilic coating layer forming composition. However, when the wettability improver is immersed in the hydrophilic coating layer forming composition in the form of supporting the wettability improving agent on the pores, the wettability improving agent is released from the nanofiber web and at the same time the time required for the hydrophilic coating layer forming composition to penetrate into the pores The manufacturing time can be prolonged. Further, as the degree of penetration of the hydrophilic coating layer forming composition differs depending on the thickness of the nanofiber web and the diameter of the pores, the hydrophilic coating layer can be formed nonuniformly according to the position of the fibrous web. Further, as the hydrophilic coating layer is non-uniformly formed, the pores may be closed by the hydrophilic coating layer in a part of the nanofiber web, and in this case, the pore structure of the nanofiber web designed in the beginning may change, Providing the wettability improving agent in the hydrophilic coating layer forming composition is advantageous in achieving to simultaneously achieve a shortening of the manufacturing time, a simplification of the manufacturing process and an improvement of the hydrophilic coating layer formation without changing the pore structure of the nanofiber web.

The method of forming the hydrophilic coating layer-forming composition on the nanofiber web may be applied to any known coating method without limitation. For example, immersion, spraying and the like can be used.

And then forming a hydrophilic coating layer by heat-treating the hydrophilic coating layer-forming composition treated on the nanofiber web. The drying process of the solvent in the hydrophilic coating layer-forming composition can be performed at the same time through the heat treatment. The heat treatment may be performed in a dryer, and the heat applied at this time may be 80-160 ° C., and the treatment time may be 1 minute to 60 minutes, but is not limited thereto.

Next, in step (3) according to the present invention, a step of fabricating a filter material by providing a filter material on both surfaces of a first support having a plurality of through holes is performed.

The step (3) includes: 3-1) laminating the filter material produced in the step (2) on both sides of a first support having a plurality of through holes formed therein; And 3-2) fusing the laminated first support and the filter media by applying at least one of heat and pressure.

As a specific method of applying the heat and / or pressure in the step 3-2), a known method may be adopted. As a non-limiting example, a conventional calendering process can be used, and the temperature of the applied heat is 70 To 190 < 0 > C. When the calendering process is carried out, it may be carried out a plurality of times, for example, a first calendering followed by a second calendering. At this time, the degree of heat and / or pressure applied in each calendering process may be the same or different. Through the above step 3-2), the binding between the second support and the first support through thermal fusion may occur, and an additional adhesive or adhesive layer may be omitted.

The present invention includes a filter unit implemented with a filter material manufactured through the above-described manufacturing method.

As shown in FIGS. 6A and 6B, the filter filter material 1000 may be implemented as a flat filter unit 2000. More specifically, the flat filter unit 2000 includes a filter filter material 1000 and a support frame 1100 for supporting a rim of the filter filter material 1000. In one region of the support frame 1100, A suction port 1110 capable of slanting the pressure difference between the outside and the inside of the main body 1000 can be provided. 6B, the support frame 1100 is provided with a flow path E through which the filtrate filtered at the filter media 101 and 102 can be discharged to the outside through the first support 200 inside the filter filter media 1000 Respectively.

When a high pressure suction force is applied to the filter module 2000 shown in FIG. 6A through the inlet port 1110, the overflow fluid S disposed outside the filter filter material 1000, as shown in FIG. 6B, And the filtrate T ₁ which has been filtered through the filter media 101 and 102 flows along the flow path formed through the first support body 200 and then flows into the flow path E provided in the outer frame 1100 The introduced filtrate T ₂ may be discharged to the outside through the inlet 1110. At this time, the flow path (R ₂₎ further increases the first direction than that of the filter media 1000. The filtered solution (T ₁₎ was filtered into the interior of the second direction due to the hole (P) formed in the first support (200) It is possible to secure the flow path R _{1 of the} filter medium 1000 through which the fluid flow resistance inside the filter medium 1000 can be remarkably reduced, which is advantageous for obtaining an increased flow rate, can do.

7, when the filter medium 1000 'according to FIG. 5 is provided, the holes formed in the second support bodies 123 and 124 and the holes P' formed in the first support body 205, It is possible to secure the flow path R ₃ in the fourth direction which is further increased in the third direction R ₄ and the third direction R ₅ and thereby the fluid flow resistance inside the filter material 1000 ' Which may be advantageous to obtain a further increased flow rate, and the backwash efficiency may be further increased.

6A, a filter module including a plurality of filter modules spaced apart from each other by a predetermined distance may be implemented. The filter module may be stacked / A water treatment apparatus may be constituted.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

101, 103: first filter media 102, 104: second filter media
111, 112, 113, 114: nanofiber webs 121, 122, 123, 124:
131, 132: hydrophilic coating layers 200, 201, 202, 203, 204, 205:
1000,1000 ': Filter filter 2000, 2000': Filter unit

Claims (19)

First material;
Second media; And
A first support interposed between the first and second filter media and having a plurality of holes penetrating the first filter media and the second filter media to increase the flow path and minimize water permeation resistance; Contains filter media. The method according to claim 1,
Wherein the first support includes at least one of a nonwoven fabric, a fabric, and a knitted fabric. The method according to claim 1,
Wherein the first support comprises a first composite fiber including a support component and a low melting point component and at least a portion of the low melting point component being exposed on an outer surface,
Wherein the low melting point component of the first conjugate fiber is fused to the first filter medium and the second filter medium to bond the first support medium to the first filter medium and the second filter medium, respectively. The method according to claim 1,
Wherein the first support has a basis weight of 250 to 800 g / m 2 and a thickness of 2 to 8 mm. The method according to claim 1,
Wherein the hole has a diameter of 5 to 150 mm. The method according to claim 1,
Wherein the cross-section of the hole has at least one of a closed curve including at least one side line segment and a closed curve line including no line segment. The method according to claim 1,
Wherein at least one of the first filter material and the second filter material includes a nanofiber web having a three-dimensional network structure. 8. The method of claim 7,
Wherein the filter material further comprises a second support provided on one surface of the nanofiber web, and the second support is disposed to face the first support. 9. The method of claim 8,
And the second support body comprises at least one of a nonwoven fabric, a fabric, and a knitted fabric. 9. The method of claim 8,
Wherein the second support comprises a second composite fiber including a support component and a low melting point component such that at least a portion of the low melting point component is exposed on the outer surface, And filter media fused to the first support. 8. The method of claim 7,
Wherein the nanofiber web comprises a nanofiber comprising a fluorine-based compound,
The fluorine-based compound may be at least one selected from the group consisting of polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) (EPE) -based, tetrafluoroethylene-ethylene copolymer (ETFE) -based, polychlorotrifluoroethylene (PCTFE) -based, chlorotrifluoroethylene-based, ethylene-hexafluoropropylene-perfluoroalkylvinylether copolymer -Ethylene copolymer (ECTFE) -based and polyvinylidene fluoride (PVDF) -based compounds. 8. The method of claim 7,
Wherein the nanofiber web has an average pore size of 0.1 to 5 占 퐉 and a porosity of 40 to 90%. 8. The method of claim 7,
Wherein the nanofiber web comprises nanofibers and the average diameter of the nanofibers is 50 to 450 nm. 9. The method of claim 8,
The basis weight of the second support is 35 to 80 g / m 2, and the thickness is 150 to 250 μm. 9. The method of claim 8,
Wherein the second support comprises a hole penetrating the nanofiber web and an outer surface opposite the first support respectively. 16. The method of claim 15,
Wherein an average diameter of the holes provided in the second support body is smaller than an average diameter of holes provided in the first support body. The method according to claim 1,
The filter material is an ultrafiltration membrane. A filter media according to any one of claims 1 to 17, And
And a support frame for supporting the rim of the filter media, the filter having a flow path for allowing the untreated water to flow into the filter media and allowing the filtrate to flow out to the outside. A filter module comprising a plurality of filter units according to claim 18 spaced apart at predetermined intervals.

Images