JP6105891B2 - FILTER FILTER AND METHOD FOR PRODUCING FILTER FILTER - Google Patents

Description

  The present invention relates to a filter medium that collects particles contained in a gas to be filtered and a method for producing the same, and more particularly to a filter medium that can collect the particles that is pleated.

  Conventionally, a filter medium 100 as shown in FIG. 5 is known as a filter medium used in a clean room or the like of a factory that manufactures semiconductors and liquid crystals (see Patent Document 1). The filter medium 100 is formed by bending a filter medium original fabric 200 configured to collect particles contained in a gas to be filtered at a plurality of locations into a bowl shape.

  Such a filter medium 100 has a plurality of flat plate portions 100b formed so that a bent portion 100a formed by bending the filter medium original fabric 200 and an area other than the bent portion 100a in the filter medium original fabric 200 are opposed to each other. And a plurality of interval holding portions 300 that hold intervals between adjacent flat plate portions 100b, 100b.

  The interval holding unit 300 is formed of a plurality of bead units 300 a formed by applying an adhesive (hot melt or the like) at an interval to both surfaces of the filter medium original fabric 200. Specifically, the interval holding part 300 is formed by joining the bead part 300 a between the flat plate parts 100 b on one surface side and the other surface side of the filter medium original fabric 200. That is, the interval holding unit 300 is formed between the flat plate portions 100 b on one surface side and the other surface side of the filter medium original fabric 200.

  Further, the interval holding unit 300 formed on one surface side of the filter medium original fabric 200 and the interval holding unit 300 formed on the other surface side are configured so as not to overlap with each other via the flat plate portion 100b. Yes. Specifically, a plurality of interval holding portions 300 on one surface side of the filter medium original fabric 200 are formed at intervals along the bent portion 100a, and the interval holding portion 300 on the other surface side of the filter media original fabric 200 is formed. Is formed between the interval holding portions 300 on one side of the adjacent surfaces. Thereby, the usage-amount of an adhesive agent can be reduced rather than the case where the bead part 300a is formed in the whole region of the flat plate part 100b, and the space | interval holding | maintenance part 300 is formed.

JP 09-313856 A

  By the way, the filter medium 100 as described above has a force that narrows the interval between the flat plate portions 100b (specifically, a force that compresses the filter medium 100 along the direction intersecting the flat plate portion 100b). (Hereinafter also referred to as force in the compression direction) may be applied. For example, when the filter medium 100 is housed in a bag, a force in the compression direction may be applied to the filter medium 100 by the bag. Further, when the filter medium 100 is stored so that the flat plate portion 100b is in a substantially horizontal state, a force in the compression direction is applied to the filter medium 100 by its own weight.

  And if the state where the force of the compression direction was added to the filter medium 100 is maintained, there exists a possibility that the space | interval between each flat plate part 100b may be fixed in a narrow state. Specifically, in the filter medium 100 before the force in the compression direction is applied, as shown in FIG. 6A, the interval between the adjacent flat plate portions 100 b and 100 b is held by the interval holding unit 300.

  However, spaces S are formed between the flat plate portions 100b on the one surface side and the other surface side of the filter medium original fabric 200 at positions corresponding to the interval holding portions 300. For this reason, when a force in the compression direction is applied to the filter medium 100, as shown in FIG. 6 (b), each interval holding unit 300 is urged and moved to the space S side. And by such a movement of the space | interval holding | maintenance part 300, a deformation | transformation arises in each flat plate part 100b, and the space | interval of flat plate part 100b becomes narrow. And if the state where the force in the compression direction is applied to the filter medium 100 continues, the shape of each flat plate portion 100b will not be restored to the state before deformation (the state before the force in the compression direction is applied to the filter medium 100), There is a possibility that the flat plate portions 100b may be fixed in a state where the interval between the flat plate portions 100b is narrow.

  Thus, if the space | interval of each flat plate part 100b becomes narrow, the dimension of the filter medium 100 of the direction along a compression direction will become shorter than the dimension desired. For this reason, for example, when a filter unit is attached to the filter medium 100 to form a filter unit, a gap is generated between the filter medium 100 and the mold, resulting in a filter unit with poor sealing performance. Moreover, there is a possibility that the pressure loss of the filter medium 100 may increase due to the narrow interval between the flat plate portions 100b.

  Therefore, the present invention provides a filter medium capable of preventing the dimension in the direction along the compression direction from becoming shorter than the dimension before compression when the continuously applied force in the compression direction is removed, and It is an object to provide a manufacturing method thereof.

In the filter medium according to the present invention, a plurality of bent parts formed by bending a filter medium raw material capable of collecting particles contained in a gas to be filtered in a bowl shape, and regions other than the bent parts in the filter medium raw material face each other. A plurality of flat plate portions that are arranged and formed, and a plurality of flat plate portions that are formed between the respective flat plate portions on one surface side and the other surface side of the filter medium original fabric and that maintain the spacing between adjacent bent portions. A filter medium comprising a gap holding part, each gap holding part formed on one side of the filter medium original fabric, and each gap holding part formed on the other side of the filter medium original It is comprised so that it may overlap via a flat plate part, and each interval maintenance part formed in one side and the other side of the above-mentioned filter material original fabric is in the direction which intersects with the bent part extended in the shape of a straight line. It is formed so as to extend linearly along the flat plate portion, and the bent portion The length from the connection position with the flat plate portion to one end portion of each interval holding portion is 51% or more and 90% or less with respect to the length between the connection positions with the pair of bent portions in the flat plate portion, and the shrinkage rate is 2 % Or more and 8% or less .

  According to such a configuration, the interval holding portion (hereinafter also referred to as one surface side interval holding portion) formed on one surface side of the filter medium original fabric, and the interval holding formed on the other surface side of the filter media original fabric. When the force in the compression direction is applied to the filter medium, the deformation of each flat plate portion is prevented, and the portions (also referred to as the other surface side interval holding portion) are overlapped via the flat plate portion. The interval is prevented from narrowing.

  Specifically, when a force in the compression direction is applied to the filter medium, the other surface side interval holding portion (or one surface side interval) is formed between the flat plate portions on one (or the other) surface side of the original filter medium. The holding part) is energized. However, since the one-surface-side interval holding portion and the other-surface-side interval holding portion overlap with each other via the flat plate portion, the other-surface-side interval holding portion (or the one-surface-side interval holding portion) is compressed in the compression direction as described above. Even when biased by force, the other surface side space holding portion (or one surface side space holding portion) is supported by the one surface side space holding portion (or the other surface side space holding portion).

  Thereby, it is prevented that the other surface side space | interval holding | maintenance part (or one surface side space | interval holding | maintenance part) moves toward between the flat plate parts by the side of one (or the other) side of a filter-medium original fabric. For this reason, it can prevent that each flat plate part deform | transforms by the movement (specifically approach of interval holding parts) of each such space | interval holding | maintenance part, and the space | interval of each flat plate part becomes narrow. Thereby, it can prevent that the dimension of the direction along the compression direction of a filter medium becomes short.

  Further, the interval holding portion formed on one surface side of the filter medium original fabric and the interval holding portion formed on the other surface side of the filter media original fabric are overlapped via the flat plate portion at the center portion of the flat plate portion. Preferably it is comprised.

  According to such a configuration, deformation of the flat plate portion that occurs when a force in the compression direction is applied to the filter medium is more effectively prevented. For this reason, the dimension of the direction along the compression direction of a filter medium can be hold | maintained more effectively.

  Specifically, the central portion of the flat plate portion (specifically, the central portion between a pair of bent portions connected to one flat plate portion or the central portion in the direction in which the bent portion extends) is from the outer peripheral portion of the flat plate portion. Will also be less rigid. For this reason, when a force in the compression direction is applied to the filter medium, the central portion of the flat plate portion is easily deformed. For this reason, a deformation | transformation of a flat plate part is effectively prevented as mentioned above by the one surface side space | interval holding | maintenance part and the other surface side space | interval holding | maintenance part overlapping via a flat plate part in the center part of a flat plate part. Thereby, the dimension of the direction along the compression direction of a filter medium can be hold | maintained more effectively.

  According to such a configuration, the length from the connecting position between the bent portion and the flat plate portion to one end portion of each interval holding portion is 50% of the length between the connecting positions between the pair of bent portions in the flat plate portion. By exceeding, the one-surface-side interval holding portion and the other-surface-side interval holding portion overlap at the center portion of the flat plate portion via the flat plate portion. Further, since the one-surface-side interval holding portion and the other-surface-side interval holding portion are formed from the position intersecting the bent portion to the center portion of the flat plate portion, the one-surface-side interval holding portion and the other-surface-side interval are The rigidity of the flat plate portion positioned between the holding portion and the flat plate portion can be further suppressed from being deformed.

The method for producing a filter medium according to the present invention includes a plurality of bent parts formed by bending a filter medium original fabric that can collect particles contained in a gas to be filtered into a bowl shape, and other than the bent parts of the filter medium original film. Maintains the distance between adjacent bent portions formed between a plurality of flat plate portions formed so as to be opposed to each other and each flat plate portion on one surface side and the other surface side of the filter medium original fabric. A plurality of interval holding portions, and a method for producing a filter medium having a shrinkage rate of 2% or more and 8% or less ,
Forming a bead portion by applying an adhesive so as to overlap both sides of a region of the filter material raw material where each flat plate portion is formed via the filter material raw material , and after the step, forming the filter material raw material into a bowl shape A plurality of bent portions and a plurality of flat plate portions are formed by bending, and the adhesives on one surface side of the filter medium original fabric are between the flat plate portions on one surface side and the other surface side of the filter media original fabric. And bonding the adhesives on the other side, and forming a gap holding part on one side and the other side of the filter medium so as to overlap with each flat plate part ,
In the step of arranging the adhesive, the adhesive is applied so that the bead application length ratio is 51% or more and 90% or less .

  As described above, according to the present invention, when the continuously applied force in the compression direction is removed, the dimension in the direction along the compression direction is prevented from becoming shorter than the dimension before compression. Can do.

The perspective view which showed the filter material which concerns on this embodiment. The perspective view and partial enlargement which showed the filter-medium original fabric which concerns on the same embodiment. (A) is sectional drawing which cut | disconnected the filter medium which concerns on the same embodiment in the surface which cross | intersects a flat plate part, (b) is a surface along the length direction and the width direction of a filter filter medium for a space | interval holding | maintenance part superposition | polymerization part. Sectional drawing which cut | disconnected. (A) is sectional drawing which showed the space | interval holding | maintenance part of the filter medium which concerns on other embodiment, (b) is sectional drawing which showed the space | interval holding | maintenance part of the filter medium which concerns on other embodiment. The perspective view which showed the conventional filter medium. It is sectional drawing which cut | disconnected the filter medium of FIG. 5 in the surface which cross | intersects each flat plate part, Comprising: (a) is sectional drawing which showed the state before the force of a compression direction is added to a filter medium, (b) Sectional drawing which showed the state in which the force of the compression direction was added to the filter medium.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  In the filter medium 1 according to the present embodiment, as shown in FIG. 1, a filter medium original fabric 2 configured to collect particles contained in a gas to be filtered is bent in a bowl shape (hereinafter also referred to as pleating). A plurality of bent portions 1a formed, a plurality of flat plate portions 1b formed so as to face areas other than the bent portion 1a in the filter medium original fabric 2, and one surface side of the filter media original fabric 2 and A plurality of interval holding portions 3 formed between the flat plate portions 1b on the other surface side and holding the intervals between the adjacent bent portions 1a and 1a are provided.

  As shown in FIG. 2, the filter medium original fabric 2 is formed in a planar shape having a longitudinal direction as shown in FIG. 2 before being bent into a bowl shape. In addition, the filter medium raw fabric 2 may be configured to be flat when unwound from a state where it is formed in a long shape so that one direction is longitudinal, and one direction is longitudinal. It may be a sheet formed in a flat shape so that

  Moreover, the filter medium original fabric 2 includes a porous layer 2a that collects particles contained in the gas to be filtered, and a base material layer 2b that has air permeability and is laminated on the porous layer 2a. In the present embodiment, the filter medium original fabric 2 includes a plurality of (specifically, two) porous layers 2a, and the base material layer 2b is disposed between the porous layers 2a. Thus, by forming the filter medium original fabric 2 using a plurality of porous layers 2a, pressure loss and collection efficiency are higher than when the filter media original fabric 2 is formed from a single porous layer 2a. It is possible to suppress the occurrence of variations. Moreover, since it can suppress that a pinhole which penetrates the filter-medium original fabric 2 is formed, the filter-medium original fabric 2 of a leakless structure can be obtained.

  The porous layer 2a is formed using a porous sheet material (hereinafter also referred to as a porous sheet) capable of collecting the particles. The porous sheet is not particularly limited, and can be appropriately selected depending on the use of the filter medium 1. For example, a PTFE sheet in which polytetrafluoroethylene (PTFE) is formed in a sheet shape can be used. As a method for forming the PTFE sheet, for example, the following method can be employed.

  Specifically, a liquid lubricant is added to the PTFE fine powder to form a paste-like mixture. The PTFE fine powder is not particularly limited. For example, Polyflon F-104 (manufactured by Daikin Industries), Fullon CD-123 (manufactured by Asahi ICI Fluoropolymers), Teflon 6J (Mitsui / Dupont Fluorochemical) Etc.) can be used. The liquid lubricant is not particularly limited as long as it can impart appropriate wettability to the surface of the mixture, and is particularly preferable if it can be removed by extraction treatment or heat treatment. For example, in addition to hydrocarbon oils such as liquid paraffin, naphtha, white oil, toluene, and xylene, alcohols, ketones, esters, and mixtures of two or more of these can be used as the liquid lubricant. The addition amount of the liquid lubricant is not particularly limited, but is appropriately adjusted according to the type of PTFE fine powder and liquid lubricant, and the molding method when obtaining the PTFE sheet. Specifically, the addition amount of the liquid lubricant is preferably 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the PTFE fine powder.

  And the said mixture which consists of PTFE fine powder and a liquid lubricant is preformed, and a preformed body is produced. Specifically, a preform is produced by extruding the mixture into a rod shape. Such preforming is preferably performed at a pressure that does not separate the liquid lubricant from the mixture.

  Next, the obtained preform is formed into a sheet by extrusion or rolling. Specifically, a preform is supplied between a pair of rolls and rolled to form a sheet, a sheet is extruded, or a sheet is extruded and formed between a pair of rolls. And a method of forming it into a sheet by rolling it. The thickness of the obtained sheet-like molded body is not particularly limited, and is preferably 0.05 mm or more and 0.5 mm or less, for example.

  Next, the obtained sheet-like molded body is made uniaxially stretched or biaxially stretched to obtain a PTFE sheet. In the present embodiment, the sheet-like molded body is stretched along the longitudinal direction and is also stretched along the width direction orthogonal to the longitudinal direction (biaxial stretching). In addition, before extending | stretching a sheet-like molded object, it is preferable to remove a liquid lubricant from this molded object. As a method of removing the liquid lubricant, a method of heating the molded body (heating method) or a method of extracting the liquid lubricant by immersing the molded body in a solvent (extraction method) can be employed.

  When the sheet-like molded body is stretched along the longitudinal direction, fibrillation of the molded body is promoted and the porous body is more easily made when the stretch ratio is larger. As a draw ratio, it is preferable that it is 10 times or more and 30 times or less, for example. Moreover, it does not specifically limit as temperature conditions at the time of extending | stretching this molded object, For example, it is preferable that it is 150 to 327 degreeC.

  By stretching the sheet-like molded body after being stretched along the longitudinal direction along the width direction, the molded body can be effectively fibrillated, and a PTFE sheet with less variation in pore diameter can be obtained. it can. The conditions for stretching the sheet-like molded body along the width direction are not particularly limited. For example, the stretching ratio is preferably 20 times or more and 100 times or less. Further, it is preferable to stretch the sheet-like molded body along the width direction so that the area stretch ratio represented by the product of the stretch ratio in the longitudinal direction is 450 times or more. Fibrilization is further promoted as the area stretch ratio is larger, and a porous PTFE sheet having a large PF value can be obtained. Moreover, it does not specifically limit as extending | stretching temperature, For example, it is preferable that it is 40 to 100 degreeC.

The PTFE sheet formed as described above has excellent characteristics such that the pressure loss is 50 mmH ₂ O or less and the collection efficiency is 99.9% or more. In particular, when the area stretch ratio is 450 times or more, the pressure loss can be reduced to less than 20 mmH ₂ O without greatly reducing the collection efficiency, and the PF value is 22 or more, which is extremely excellent. It becomes a porous PTFE sheet of performance. Further, the variation in pressure loss for each obtained PTFE sheet is reduced. For this reason, it becomes a porous PTFE sheet which has low operating costs and exhibits extremely excellent dust removal performance.

Note that the PTFE sheet obtained as described above may be further subjected to heat treatment (firing treatment) in order to increase strength and obtain dimensional stability. The heat treatment of the PTFE sheet is usually performed with the dimensions fixed above the melting point of the PTFE fired body. Moreover, it becomes possible to reduce a pressure loss by such heat processing. For this reason, when the PF value of the PTFE sheet is 22 or more and the pressure loss is 20 mmH ₂ O or more, the heat loss can be reduced to less than 20 mmH ₂ O by this heat treatment.

  The PTFE sheet formed as described above preferably has an endothermic peak in a temperature range of 345 ± 5 ° C. on the crystal melting curve by a differential scanning calorimeter. Moreover, it is preferable that such a PTFE sheet has a crystal conversion rate of 0.25 or more and 0.85 or less. In addition, such a PTFE sheet preferably has a specific gravity (“apparent specific gravity” obtained by dividing the mass by the apparent volume) of 1.4 or less.

  The base material layer 2b is formed using a breathable sheet material (hereinafter also referred to as a breathable sheet). The breathable sheet is not particularly limited, and for example, a nonwoven fabric, a woven fabric, a mesh, or the like can be used. In particular, when the porous layer 2a (porous layer sheet) and the base material layer 2b (breathable sheet) are thermally welded (heat laminated), it is preferable to use a breathable sheet made of a thermoplastic material. .

  Examples of the material of the breathable sheet include polyolefins such as polyethylene and polypropylene, nylon, polyester, aramid (specifically, aromatic polyamide), or a composite of these (for example, core / sheath structure). And a non-woven fabric made of fibers and a two-layer non-woven fabric of a low melting point material and a high melting point material). In addition, examples of the material of the air-permeable sheet include fluorine such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), and a porous film of PTFE. System porous membranes.

  In particular, a core-sheath composite fiber having a core component having a relatively higher melting point than the sheath component, a non-woven fabric composed of synthetic fibers, a non-woven fabric composed of two layers of a low melting point material and a high melting point material, and the like. Is preferably used. By using such a nonwoven fabric, when the porous layer 2a (porous layer sheet) and the base material layer 2b (breathable sheet) are heat-laminated, the shrinkage of the base material layer 2b is suppressed. Is possible. Moreover, by using such a nonwoven fabric, the workability at the time of pleating becomes favorable, and it becomes possible to increase the locations (folding pitch) where the filter medium raw fabric 2 is bent.

  The method of forming the filter medium raw fabric 2 as described above is not particularly limited, and for example, between the porous sheet that forms the porous layer 2a and the breathable sheet that forms the base material layer 2b. It is possible to employ a method in which a hot melt or pressure sensitive adhesive is disposed on the porous sheet and the porous sheet and the breathable sheet are pressure-bonded. Alternatively, it is possible to employ a method in which a breathable sheet is heated and softened to be pressure-bonded (thermally laminated) to the porous sheet.

  When the filter medium 1 is formed using the filter medium original fabric 2 configured as described above, first, the filter medium original fabric 2 is pleated. Specifically, the filter medium original fabric 2 is bent at a plurality of locations along the width direction orthogonal to one direction (longitudinal direction) to form a bowl shape. As a result, the bent portion 1 a and the flat plate portion 1 b of the filter medium 1 are formed on the filter medium original fabric 2. In the following description, a region where the bent portion 1a is formed in the filter medium original fabric 2 is defined as a planned bending region A1.

  Next, an adhesive is applied to both surfaces of the filter medium original fabric 2 to form a bead portion 3a. Specifically, an adhesive is applied to both sides of the filter medium original fabric 2 while the bead portion 3a is formed while the filter medium original fabric 2 formed in a bowl shape is stretched into a flat state before pleating. The bead portion 3 a is partially formed on each of both surfaces of the filter medium original fabric 2. Specifically, each of the bead portions 3a (hereinafter also referred to as one side bead portion and the other side bead portion) 3a formed on one surface side and the other surface side of the filter medium original fabric 2 is a filter media original fabric. A plurality of (three in the present embodiment) are formed at intervals along the width direction of the filter medium original fabric 2. Further, the one surface side bead portion 3 a and the other surface side bead portion 3 a are formed on the same straight line along one direction (longitudinal direction) of the filter medium original fabric 2.

  Moreover, it does not specifically limit as a shape of the bead part 3a, In this embodiment, it forms in linear form along one direction (longitudinal direction) of the filter-medium original fabric 2. FIG. Moreover, the bead part 3a is formed in the vicinity of the surface which becomes the mountain side when the bent part 1a in the planned bending area A1 is formed. Specifically, the bead portion 3 a is formed so as to intersect the planned bending region A <b> 1 in the filter medium original fabric 2. In this embodiment, it is comprised so that bead part 3a and the bending plan area | region A1 may cross | intersect at the approximate center part of the bead part 3a formed in linear form. Moreover, the bead part 3a is formed on the surface which becomes a mountain side when the bending part 1a is formed. That is, among the adjacent bending planned areas A1 and A1, one bending planned area A1 and the one surface side bead part 3a intersect, and the other bending planned area A1 and the other surface side bead part 3a intersect. Configured.

  Further, the length from the intersecting position of the bead portion 3a and the bend planned region A1 to the end portion of the bead portion 3a is not particularly limited, but the bead coating length ratio exceeds 50%. Preferably there is. The bead coating length ratio refers to the ratio of the length from the intersecting position of the bead portion 3a and the planned bending region A1 to one end portion of the bead portion 3a with respect to the distance between the adjacent planned bending regions A1 and A1. In other words, the bead portion 3a is located at the center of the region A2 (that is, the region A2 to be the flat plate portion 1b) (hereinafter referred to as the flat plate portion planned region A2) between the adjacent bending planned regions A1 and A1 from the intersection with the planned bending region A1. It is formed to a position exceeding the part. In addition, the distance between adjacent bending plan area | regions A1 and A1 is along the one direction (longitudinal direction) of the filter medium original fabric 2 with the center part of one bending plan area | region A1, and the center part of the other bending plan area | region A1. The distance that is tied.

  Further, the one surface side bead portion 3a and the other surface side bead portion 3a are formed so as to overlap with each other through the filter medium original fabric 2 (specifically, the flat plate portion planned region A2). In more detail, it is on the same straight line along one direction (longitudinal direction) of the filter medium original fabric 2 among the one-surface-side bead portion 3a and the other-surface-side bead portion 3a that intersect with each of the adjacent bending planned regions A1 and A1. What is formed is formed so as to overlap with each other through the filter medium original fabric 2 in the flat plate portion planned region A2. Further, the one surface side bead portion 3a and the other surface side bead portion 3a are formed such that ends located inside the flat plate portion planned area A2 are overlapped with each other via the filter medium original fabric 2. In addition, the overlapping position of the one surface side bead portion 3a and the other surface side bead portion 3a in the flat plate portion planned region A2 is not particularly limited, but is along one direction (longitudinal direction) of the filter medium original fabric 2. It is preferable that it is a substantially central portion in the direction.

  It does not specifically limit as an adhesive agent which comprises the bead part 3a, For example, a hot melt can be used. The temperature at which the hot melt is applied to the filter medium original fabric 2 varies depending on the components of the hot melt, but is preferably 100 ° C. or higher and 250 ° C. or lower, and more preferably 140 ° C. or higher and 230 ° C. or lower. .

  And the filter-medium original fabric 2 in which the bead part 3a was formed as mentioned above is bent again in each bending plan area | region A1, and is formed in bowl shape. Thereby, as shown to Fig.3 (a), while the some bending part 1a and the some flat plate part 1b are formed, the site | part located between each flat plate part 1b in each bead part 3a joins, and is spaced. The holding part 3 is formed, and the filter medium 1 is formed. For this reason, when hot melt is used for the adhesive constituting the bead portion 3a, when the hot melt is softened to such a degree that it can be joined (within the open time), the filter medium raw fabric 2 is again made into a bowl-like shape. It is preferable to form.

  In the following description, a direction corresponding to one direction (longitudinal direction) of the filter medium original fabric 2 in the filter medium 1 is defined as a length L1 of the filter medium 1. A direction corresponding to the other direction (width direction) of the filter medium original fabric 2 in the filter medium 1 is defined as a width L2 of the filter medium 1. Moreover, the space | interval between the bending part 1a formed so that one surface side of the filter-medium original fabric 2 may become a peak side, and the bending part 1a formed so that the other surface side of the filter-medium original fabric 2 may become a peak side may be set. The height of the filter medium 1 is L3.

  In the filter medium 1 formed as described above, the interval holding portions 3 are formed on each of the one surface side and the other surface side of the filter medium original fabric 2. Further, each interval holding unit 3 is formed in a straight line shape from one side in the height L3 direction of the filter medium 1 toward the other side. In addition, each space holding portion 3 (hereinafter also referred to as one surface side space holding portion 3) on one surface side of the filter medium 1 and each space holding portion 3 (hereinafter referred to as the other surface side space holding portion 3) on the other surface side. 3 (a) and 3 (b) are alternately arranged along the length direction of the filter medium 1 (specifically, on a straight line along the length direction).

  And the one surface side space | interval holding | maintenance part 3 and the other surface side space | interval holding | maintenance part 3 are formed so that it may overlap via the flat plate part 1b. Specifically, the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 are formed such that ends located on the center side of the flat plate portion 1b overlap with each other via the flat plate portion 1b. Moreover, the one surface side space | interval holding | maintenance part 3 and the other surface side space | interval holding | maintenance part 3 are comprised so that it may overlap via the flat plate part 1b in the approximate center part of the height L3 direction of the filter material 1. FIG. Specifically, the length from the connecting position between the bent portion 1a and the flat plate portion 1b to one end portion of each spacing holding portion 3 is the length between the connecting positions between the pair of bent portions 1a and 1a in the flat plate portion 1b. On the other hand, by being configured to exceed 50%, the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 are configured to overlap each other at a substantially central portion in the height L3 direction of the filter medium 1. .

  As described above, the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 overlap each other, so that each interval-holding portion 3 overlaps with the flat plate portion 1b along the length direction of the filter medium 1 ( Hereinafter, B1 is also formed. As shown in FIG. 3A, the interval holding portion overlapping portion B1 is formed at a substantially central portion of the filter medium 1 in the height L3 direction. Further, as shown in FIG. 3B, a plurality (specifically, three places) of the interval holding portion overlapping portions B1 are formed at intervals in the width L2 direction of the filter medium 1 as shown in FIG. Between the interval holding portion overlapping portions B1 in the width L2 direction of the filter medium 1, the interval holding portion 3 is not formed, and a space is formed between the flat plate portions 1b.

  The filter medium 1 having the above configuration is used in such a manner that the flat plate portion 1b intersects the flow direction of the gas to be filtered. Thereby, to-be-filtered gas permeate | transmits mainly the flat plate part 1b. Further, the filter medium 1 is formed so that the outer shape (the shape viewed from the height L3 direction) has a predetermined shape, and is then housed in a frame (not shown) and used as a filter unit. Also good. The shape of the frame is not particularly limited as long as the filter medium 1 can be accommodated. For example, the frame has a rectangular parallelepiped shape having an inner dimension of 1180 mm × 1180 mm, an outer dimension of 1220 mm × 1220 mm, and a thickness of 75 mm, The circular thing etc. which have an internal diameter are mentioned. The material of the frame is not particularly limited, and aluminum can be used.

  A caulking agent is filled between the filter medium 1 and the frame. As the caulking agent, for example, a two-component epoxy caulking agent (specifically, a mixture of Macroplast 8104MC-18 manufactured by Henkel and Macroplast UK5400 in a ratio of 3: 1) can be used. Further, the filter medium 1 is suitably used as a high efficiency particulate air (HEPA) filter such as a clean room and an ULPA (Ultra Low Penetration Air) filter.

  As described above, according to the filter medium and the manufacturing method thereof according to the present invention, when the continuously applied force in the compression direction is removed, the dimension along the compression direction is the dimension before compression. Can be prevented.

  That is, when the filter medium 1 is overlapped with the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 via the flat plate portion 1b, when a force in the compression direction is applied to the filter medium 1, The deformation of each flat plate portion 1b is prevented, and the interval between the flat plate portions 1b is prevented from being narrowed.

  Specifically, when a force in the compression direction is applied to the filter medium 1, the other-surface-side spacing holding section 3 (the other-surface-side spacing holding section 3 (between the flat plate sections 1 b, 1 b on one (or the other) surface side of the filter medium original fabric 2). Alternatively, the one-surface-side interval holding unit 3) is biased.

  However, since the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 overlap with each other via the flat plate portion 1b, the other-surface-side interval holding portion 3 (or the one-surface-side interval holding portion 3 as described above). ) Is urged by the force in the compression direction, the other surface side space holding portion 3 (or one surface side space holding portion 3) is replaced by the one surface side space holding portion 3 (or the other surface side space holding portion 3). Supported by.

  Thereby, the other surface side space | interval holding | maintenance part 3 (or one surface side space | interval holding | maintenance part 3) moves toward between the flat plate parts 1b and 1b of one (or the other) surface side of the filter medium raw fabric 2. Is prevented. For this reason, it is possible to prevent the flat plate portions 1b from being deformed by the movement of the respective gap holding portions 3 (specifically, the proximity of the gap holding portions 3 to each other) and the gap between the flat plate portions 1b to be narrowed. Can do. Thereby, it can prevent that the dimension (dimension of length L1 direction) of the direction along the compression direction of the filter material 1 becomes short.

  Further, the central portion of the flat plate portion 1b (specifically, the central portion between the pair of bent portions 1a, 1a connected to one flat plate portion 1b or the central portion in the direction in which the bent portion 1a extends) is the flat plate portion 1b. The rigidity is lower than that of the outer peripheral portion. For this reason, when the force of a compression direction is added to the filter medium 1, the center part of the flat plate part 1b becomes easy to deform | transform. For this reason, the deformation | transformation of the flat plate part 1b is effective as mentioned above by the one surface side space | interval holding | maintenance part 3 and the other surface side space | interval holding | maintenance part 3 overlapping via the flat plate part 1b in the center part of the flat plate part 1b. Is prevented.

  Further, the length from the connecting position between the bent portion 1a and the flat plate portion 1b to one end portion of each spacing holding portion 3 is 50 with respect to the length between the connecting positions between the pair of bent portions 1a and 1a in the flat plate portion 1b. By exceeding%, the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 overlap with each other through the flat plate portion 1b at the central portion of the flat plate portion 1b. Moreover, since the one surface side space | interval holding | maintenance part 3 and the other surface side space | interval holding | maintenance part 3 will be formed ranging from the position which cross | intersects the bending part 1a to the center part of the flat plate part 1b, the one surface side space | interval holding | maintenance part 3 And the rigidity of the flat plate portion 1b located between the other surface side interval holding portion 3 can be improved, and deformation of the flat plate portion 1b can be further suppressed.

  The filter medium and the manufacturing method thereof according to the present invention are not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention. Further, the configurations and methods of the plurality of embodiments described above may be arbitrarily adopted and combined (even if the configurations and methods according to one embodiment are applied to the configurations and methods according to other embodiments). Of course, it is of course possible to arbitrarily select configurations, methods, and the like according to various modifications described below and employ them in the configurations, methods, and the like according to the above-described embodiments.

  For example, in the above embodiment, the bead portion 3a is formed so as to intersect the bent portion 1a, but the present invention is not limited to this, and as shown in FIG. Bead part 3a 'may be formed only from the part to form. Alternatively, as shown in FIG. 4B, the bead portion 3 a ″ and the interval holding portion 3 ″ may be constituted only by the portion constituting the interval holding portion overlapping portion B 1 of the filter medium 1.

  Moreover, in the said embodiment, although the space | interval holding | maintenance part 3 is formed in multiple numbers at intervals along the bending part 1a, it is not limited to this, It forms integrally along the bending part 1a. Also good.

  Moreover, in the said embodiment, although the filter-medium original fabric 2 is bent in multiple places along the width direction, it is not limited to this, The filter-medium original fabric formed in the sheet form is radial A conical filter medium may be formed by bending at a plurality of locations.

  Moreover, in the said embodiment, although the filter medium 1 is comprised using the filter medium raw fabric 2 which consists of the porous layer 2a and the base material layer 2b, it is not limited to this, For example, a porous layer You may use the filter-medium original fabric formed only from 2a. Moreover, in the said embodiment, although the filter-medium original fabric 2 is formed using the several porous layer 2a, it is not limited to this, From the single porous layer 2a and the base material layer 2b A filter medium original fabric may be formed.

  Moreover, in the said embodiment, the one surface side space | interval holding | maintenance part 3 (one surface side bead part 3a) and the other surface side space | interval holding | maintenance part 3 (other surface side bead part 3a) are flat plate part 1b (flat plate part planned area | region A2). However, the present invention is not limited to this. For example, the entire portion located inside the flat plate portion 1b (the flat plate portion planned area A2) is configured to overlap each other. You may be comprised so that it may mutually overlap.

  Moreover, in the said embodiment, although the one surface side space | interval holding | maintenance part 3 and the other surface side space | interval holding | maintenance part 3 are comprised so that it may overlap in the approximate center part of the height L3 direction of the flat plate part 1b, it is limited to this. Instead, the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 may be configured to overlap each other at a position deviating from the central portion of the flat plate portion 1b to the outer peripheral side of the flat plate portion 1b.

  Examples of the present invention will be described below.

<Preparation of filter media>
1. Porous sheet A PTFE sheet was used as the porous sheet. Specifically, 19 parts by weight of a liquid lubricant (normal decane) was added to 100 parts by weight of PTFE fine powder (trade name: F104, manufactured by Daikin Industries, Ltd.) to obtain a paste-like mixture. And after pre-molding this mixture, the flat molded object from which one direction becomes a longitudinal direction was obtained by extrusion molding. Then, this flat molded object was rolled so that thickness might be set to 0.2 mm. And in order to remove a liquid lubricant from a flat molded object, this molded object was heated at 150 degreeC in the drying furnace. Thereafter, the flat molded body was stretched 15 times along the longitudinal direction in an environment of 280 ° C., and stretched 15 times along the width direction orthogonal to the longitudinal direction in an environment of 100 ° C. Got.

2. Breathable sheet As the breathable sheet, a PET / PE core-sheath nonwoven fabric (trade name: T1003WDO manufactured by Unitika Ltd.) formed so that one direction is the longitudinal direction was used.

3. Fabrication of the filter medium raw material A pair of roller members (the heat roller and the support roller) while laminating the porous sheet on both sides of the air permeable sheet so that the longitudinal directions of the porous sheet and the air permeable sheet are substantially parallel to each other ), And the porous sheet and the breathable sheet were heat-sealed and bonded together to produce a filter medium original fabric 2 as shown in FIG. In addition, as each roller member, that whose outer diameter is 200 mm was used. Moreover, the conveyance speed of each sheet | seat was 10 m / min, and the pressure at the time of bonding was 0.8 MPa.

4). Pleated processing After the obtained filter medium 2 was pleated, a bead portion 3a was formed as shown in FIG. 2 to produce a filter medium 1 as shown in FIGS. As an adhesive (hot melt) forming the bead portion 3a, Macromelt 6202 (polyamide type) manufactured by Henkel or Technomelt Q3115 (EVA type) manufactured by Henkel was used.

<Example 1>
= Filter media =
The filter medium 1 was produced by the above method so that the length L1 was 1298 mm, the width L2 was 1180 mm, and the height L3 was 35 mm. The adhesive (hot melt) forming the bead part 3a and the bead coating length ratio are shown in Table 1 below.

= Measurement of shrinkage rate =
The filter medium 1 is arranged in a plane so that the flat plate portion 1b of the obtained filter medium 1 is substantially horizontal (in other words, the length L1 direction of the filter medium 1 is substantially vertical), and the filter medium A load of 3 kg was applied to 1 along the length L1 direction from above.
And the length L1 of the filter material 1 after applying a load was measured, and the shrinkage rate was computed from the following (2) formula. The calculated shrinkage is shown in Table 1 below.

Shrinkage rate (%) = {(length of filter medium before loading−length of filter medium after loading) / length of filter medium before loading} × 100 (2)

= Sealability of filter unit =
The obtained filter medium 1 was housed in a frame to produce a filter unit. Specifically, the filter medium 1 is accommodated in an aluminum frame having an inner dimension of 1180 mm × 1180 mm, an outer dimension of 1220 mm × 1220 mm, and a thickness of 75 mm, and a caulking agent is filled between the filter medium 1 and the frame. Thus, a filter unit was produced. As the caulking agent, a two-component epoxy caulking agent (specifically, a mixture of Macroplast 8104MC-18 manufactured by Henkel and Macroplast UK5400 at a ratio of 3: 1) was used.
When the filter unit is produced, “◯” indicates that no gap is formed between the filter medium 1 and the frame, and “X” indicates that the gap is formed. Evaluated. The evaluation results are shown in Table 1 below.

<Examples 2 to 6, Comparative Examples 1 and 2>
As the adhesive (hot melt) for forming the bead portion 3a, a filter is used under the same conditions as in Example 1 except that the adhesive shown in the following Table 1 is used and the bead coating length ratio is as shown in the following Table 1. The filter medium 1 and the filter unit were produced and the shrinkage rate was measured. The shrinkage rate and the evaluation of the sealing performance of the filter unit are shown in Table 1 below.

<Summary>
When each example and each comparative example are compared, it is recognized that each example has a lower shrinkage rate than each comparative example. This is because the bead coating length ratio is 50% or more as in each of the examples, and the one-surface-side interval holding portion 3 and the other-surface-side interval holding portion 3 are substantially the central portion of the flat plate portion 1b. This is because the gap holding portion overlapping portion B1 is formed along the length L1 direction of the filter medium 1 due to the overlapping state. As a result, even when a load (force in the compression direction) is applied to the filter medium 1, such a load is supported by the interval holding portion overlapping portion B1, and deformation of the flat plate portion 1b can be suppressed. For this reason, the space | interval of flat plate part 1b is maintained, and shrinkage | contraction of the filter material 1 is suppressed.
That is, it is recognized that the shrinkage of the filter medium 1 can be suppressed by forming the one surface side interval holding portion 3 and the other surface side interval holding portion 3 so as to overlap with each other via the flat plate portion 1b.

  DESCRIPTION OF SYMBOLS 1 ... Filter medium, 1a ... Bending part, 1b ... Flat plate part, 2 ... Filter medium original fabric, 2a ... Porous layer, 2b ... Base material layer, 3 ... Space | interval holding | maintenance part, 3a ... Bead part, A1 ... Plane bending area | region, A2 ... Plane portion planned area, B1 ... Space holding portion overlapping portion

Claims (3)

A plurality of bent portions formed by bending a filter medium original fabric capable of collecting particles contained in the gas to be filtered in a bowl shape and an area other than the bent portions in the filter medium original fabric are arranged so as to face each other. Filter medium comprising a plurality of flat plate portions and a plurality of gap holding portions formed between the flat plate portions on one surface side and the other surface side of the filter medium original fabric to hold the intervals between adjacent bent portions. Because
Each interval holding portion formed on one surface side of the filter medium original fabric and each interval holding portion formed on the other surface side of the filter media original fabric are configured to overlap via each flat plate portion. ,
Each interval holding portion formed on one surface side and the other surface side of the filter medium original fabric is formed so as to extend linearly along the flat plate portion in a direction intersecting with the bending portion extending linearly. In addition, the length from the connecting position of the bent portion and the flat plate portion to one end portion of each interval holding portion is 51% or more and 90% or less with respect to the length between the connecting positions of the flat plate portion and the pair of bent portions. Yes,
A filter medium having a shrinkage rate of 2% or more and 8% or less .   The interval holding portion formed on one surface side of the filter medium original fabric and the interval holding portion formed on the other surface side of the filter media original fabric are configured to overlap with each other through the flat plate portion at the center portion of the flat plate portion. The filter medium according to claim 1, wherein A plurality of bent portions formed by bending a filter medium original fabric capable of collecting particles contained in the gas to be filtered in a bowl shape and an area other than the bent portions in the filter medium original fabric are arranged so as to face each other. A plurality of flat plate portions and a plurality of interval holding portions that are formed between the respective flat plate portions on one surface side and the other surface side of the filter medium original fabric and hold the interval between adjacent bent portions , and contract A method for producing a filter medium having a rate of 2% or more and 8% or less ,
Forming a bead portion by applying an adhesive so as to overlap both sides of a region of the filter material raw material where each flat plate portion is formed via the filter material raw material , and after the step, forming the filter material raw material into a bowl shape A plurality of bent portions and a plurality of flat plate portions are formed by bending, and the adhesives on one surface side of the filter medium original fabric are between the flat plate portions on one surface side and the other surface side of the filter media original fabric. And bonding the adhesives on the other side, and forming a gap holding part on one side and the other side of the filter medium so as to overlap with each flat plate part ,
In the step of arranging the adhesive, the adhesive is applied so that the bead application length ratio is 51% or more and 90% or less .

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