TWI618566B - Filter material and method for manufacturing filter material - Google Patents

Abstract

An object of the present invention is to provide a filter medium which can reduce a pressure loss by suppressing a decrease in gas permeability of a porous layer during production of a filter medium.

In order to solve the problem, the present invention is characterized in that the bending portion is formed by bending the blank of the filter material and forming it in one direction, and the flat portion is formed into a plate shape other than the curved portion of the filter material blank; At least a portion of the adhesive portion to which the porous layer and the base material layer are adhered is formed inside the curved portion, and the non-adhered portion of the non-adhered porous layer and the base material layer is formed on the flat plate portion.

Description

Filter filter material and filter filter material manufacturing method Technical field

The present invention relates to a filter medium for trapping particles contained in a filtered gas, and a method for producing the same, and more particularly to a process for folding a porous layer having the particles and a substrate layer adhered to the porous layer. Filter material blank.

Background technique

Heretofore, it has been known that a filter medium used in a clean room or the like for manufacturing a semiconductor or a liquid crystal factory is formed by a porous layer which traps particles contained in the filtered gas (for example, a composition composed of polytetrafluoroethylene, etc.) And a filter material blank adhered to the substrate layer (for example, non-woven fabric, etc.) on at least one side of the porous layer.

A method of adhering a porous layer and a substrate layer is known, for example, as a method of thermally laminating a porous layer and a substrate layer. Specifically, a method of heating a base material layer made of a material having thermoplasticity and laminating a porous layer and a base material layer in a state of being laminated with a porous layer, or heating the base material layer A method of laminating and adhering to a porous layer is known (see Patent Documents 1 and 2). In these methods, the softened substrate layer A part of the pores enter the pores of the porous layer, so that the porous layer and the substrate layer are adhered by the anchoring effect.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-990

Patent Document 2: Japanese Laid-Open Patent Publication No. 2009-101254

Summary of invention

However, as described above, when the porous layer and the base material layer are adhered by the heat build-up layer, one part of the softened base material layer enters the pores of the porous layer, so that the gas permeability of the porous layer is lowered, and the pressure loss is high. Filter media.

Accordingly, an object of the present invention is to provide a filter medium having a relatively low pressure loss by suppressing a decrease in gas permeability of a porous layer during production of a filter medium, and a method for producing the filter medium.

The filter medium of the present invention is a filter material blank which is bent at a plurality of positions to form a wrinkle shape, and the filter material has a porous layer for collecting particles contained in the filtered gas, and is adhered to the porous layer. a substrate layer on at least one of the sides; the filter medium is characterized by: a curved portion formed by bending the blank of the filter material and forming in one direction; and a flat portion forming a plate other than the curved portion of the filter material Forming a shape; and bonding at least a portion of the adhesive portion formed by adhering the porous layer to the substrate layer The non-adhesive portion of the non-adhesive layer and the base material layer is formed on the flat plate portion inside the bent portion.

According to this configuration, when the filter material blank is bent (hereinafter, also referred to as folding) into a wrinkle shape, the positional displacement of the porous layer and the base material layer can be prevented. Specifically, when the filter material is folded, the region where the curved portion of the filter material is formed (hereinafter, also referred to as a predetermined curved region) is oriented such that the porous layer and the substrate layer are displaced relative to each other (specifically In addition, a force is applied along the direction of the opposing faces of the porous layer and the substrate layer.

However, since at least a portion of the adhesive portion is formed inside the curved portion (that is, inside the curved portion of the filter material blank), the porous layer and the base material layer are formed in the predetermined curved region when the filter material is folded. The relative positional relationship is fixed. Therefore, even if a force which causes a relative positional shift between the porous layer and the base material layer is applied to a predetermined curved region of the filter material blank, the positional displacement of the porous layer and the base material layer can be prevented.

Further, since the non-adhesive portion is formed on the flat plate portion, the filter medium having a low pressure loss can be obtained as compared with the case where the adhesive portion is formed on the entire flat plate portion. Specifically, since the porous layer and the base material layer are not adhered to the non-adhesive portion, the hole is not blocked by one of the base material layers entering the pore of the porous layer, or the pore of the porous layer is not caused by the pores. Then, the porous layer and the base material layer are occluded by an adhesive. Therefore, the non-adhesive portion has higher gas permeability than the adhesive portion. Further, the filtered gas passing through the filter medium mainly passes through the flat portion of the filter material. Therefore, since the non-adhesive portion is formed on the flat plate portion, the filter medium is made to have a higher gas permeability and a lower pressure loss than the adhesive portion is formed on the entire flat plate portion.

Preferably, the adhesive portion is formed in a strip shape along the curved portion, and the curved portion is formed inside the width direction of the adhesive portion.

According to this configuration, when the filter material blank is bent into a wrinkle shape, the predetermined curved region is formed inside the width direction of the adhesive portion. Therefore, even if the predetermined curved region is displaced from the desired position, the filter material blank is also It is surely bent inside the adhesive portion. Therefore, at least a portion of the adhesive portion can be surely formed inside the curved portion.

Preferably, the holding partition portion further has a spacing between the adjacent curved portions, and the holding spacer portion is configured to correspond to the aforesaid facing surface of the filter material when the billet is bent into a wrinkle shape The inner side of the region of the adhesive portion is connected to a pair of opposing faces.

According to this configuration, even when the filter medium is elongated in a direction orthogonal to the curved portion (hereinafter, referred to as an extending direction), the porous layer and the base layer can be prevented from being partially separated. Specifically, the holding partition portion is formed by facing a pair of opposing faces (hereinafter, also referred to as a filter material facing surface) when the billet is bent into a wrinkle shape, and connecting the pair of filter material facing surfaces, thereby forming a holding partition portion (hereinafter also referred to as a one-side holding partition portion) that connects the filter material facing surface on one side of the filter material blank, and a holding partition portion that faces the filter material facing surface on the other side of the filter material blank (hereinafter, Also known as the other side retention spacer).

Therefore, when the filter medium is elongated in the extending direction, the one-side holding partition portion and the other surface-side holding partition portion are pulled apart in the extending direction. At this time, in the region of the filter blank which is located between the one-side holding spacer and the other-side holding partition, one side is pulled by the one-side holding spacer. The other side is pulled by the other side holding spacer. Therefore, the force of pulling apart the porous layer and the substrate layer is applied to the filter material blank, which may cause a space between the porous layer and the substrate layer.

However, since the holding portion is formed inside the region corresponding to the adhesive portion in the opposing surface of each of the filter materials, the adhesive portion is formed around the holding partition portion, so that the one-side holding spacer portion and the other-side holding spacer portion are separated in the extending direction. At the same time, the adhesion between the porous layer and the substrate layer between the one-side holding spacer and the other-side holding spacer is maintained by the adhesive portion around the holding spacer. Therefore, it is possible to prevent the porous layer and the base material layer from being pulled apart, and it is possible to suppress a space between the porous layer and the base material layer and increase the pressure loss of the filter medium.

The filter medium of the present invention is produced by bending a filter material billet at a plurality of positions to form a wrinkle shape, thereby forming a filter medium, and the filter material is trapped in a porous layer of particles contained in the filter gas. a method of adhering a substrate layer to at least one of the layers; the method is characterized in that when the filter material is bent to form a curved portion in one direction, at least the adhesive portion of the porous layer and the substrate layer is adhered A portion is formed on the inner side of the curved portion to form a curved portion, and the non-adhesive portion of the non-adhesive porous layer and the base material layer is formed on the flat plate portion, and the flat plate portion is other than the curved portion of the filter material blank The area is formed into a plate shape.

As described above, according to the present invention, the pressure loss can be made relatively low by suppressing the decrease in the gas permeability of the porous layer during the production of the filter medium.

1‧‧‧Filter media

1a‧‧‧Bend

1b‧‧‧ Flat section

1c‧‧‧ filter material opposite

2‧‧‧Filter material

2a‧‧‧Porous layer

2b‧‧‧ substrate layer

2c‧‧‧Adhesive Department

2d‧‧‧Non-adhesive part

2e‧‧‧Adhesive Department

3‧‧‧ Keeping the gap

3'‧‧‧ Keep the partition

3a‧‧‧The edge of the circle

3b‧‧‧The edge of the circle

A1‧‧‧adhesive area

A2‧‧‧Predetermined bending area

Fig. 1 is a perspective view showing a filter medium of the embodiment.

Fig. 2 is a perspective view and a partially enlarged cross-sectional view showing the filter material used in the filter medium of the embodiment.

Fig. 3 is a cross-sectional view and a partially enlarged cross-sectional view showing the filter medium of the embodiment.

Figure 4 is a partial cross-sectional view showing the filter medium of the present embodiment.

Fig. 5 (a) is a perspective view showing a filter material blank constituting the filter medium of another embodiment, and Fig. 5 (b) is a cross-sectional view showing a holding partition portion of the filter medium of another embodiment.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described with reference to Figs. 1 to 4 . In the following figures, the same or corresponding parts are given the same reference numerals and the description is not repeated.

As shown in Fig. 1, the filter medium 1 of the present embodiment is formed by bending a filter material blank 2 at a plurality of positions to form a wrinkle shape (hereinafter, also referred to as a folding process), and the filter material blank 2 is configured. The particles contained in the filtered gas are trapped. Therefore, the filter medium 1 is formed by a curved portion 1a in which the filter material blank 2 is bent and formed in one direction, and a flat portion 1b in which a region other than the curved portion 1a is formed (specifically, a curved portion) The flat portion between 1a and 1a).

Further, the filter medium 1 further has a holding space 3 for maintaining the interval between the adjacent curved portions 1a and 1a. The holding partition portion 3 is disposed in a pair of opposing faces when the filter material blank 2 is bent into a wrinkle shape (hereinafter, also referred to as a filter Between the material facing surfaces 1c and 1c, and then the respective filter materials facing surfaces 1c and 1c. Therefore, the pair of filter material facing surfaces 1c and 1c are connected to each other through the holding partition portion 3.

In the present embodiment, the holding partition portion 3 is formed by joining the edge portions 3a and 3a of the adhesive agent on the pair of filter material facing surfaces 1c and 1c, respectively. Specifically, the adhesive agent is applied linearly so as to traverse the side faces of the respective curved portions 1a to form the rounded edge portion 3a. Further, the holding partition portion 3 is formed by connecting the portions of the adjacent rounded edge portions 3a between the pair of filter material facing surfaces 1c and 1c. The adhesive constituting the rounded edge portion 3a is not particularly limited, and a hot melt adhesive can be used. The thickness of the rounded edge portion 3a can be appropriately set depending on the interval between the desired curved portions 1a.

Further, a plurality of the spacer portions 3 are formed at intervals in the extending direction (longitudinal direction) of each of the curved portions 1a (three in the present embodiment). Specifically, the adjacent two curved portions 1a and 1a are formed on the long side of the other curved portion 1a so as to form a plurality of respective rounded edge portions 3a at intervals in the longitudinal direction of the curved portion 1a. A plurality of rounded edge portions 3a are formed in the direction interval, whereby the adjacent rounded edge portions 3a and 3a are coupled to each other, and a plurality of holding gap portions 3 are formed at intervals in the longitudinal direction of each curved portion 1a.

As shown in FIG. 2, the filter material blank 2 is formed so that the other direction (longitudinal direction) orthogonal to the one direction (the direction in which the curved portion 1a extends) is a long side. Further, the filter material blank 2 is configured such that a plurality of curved portions 1a are bent at a plurality of positions in one direction (width direction). Further, the filter material blank 2 may be formed into a sheet shape by being unwound from a state in which it is formed into a long shape and wound, or may be formed into a single piece shape having a predetermined length.

Moreover, the filter material blank 2 has particles for trapping the filtered gas The porous layer 2a and the base material layer 2b having gas permeability and laminated on at least one surface of the porous layer 2a. In the present embodiment, the base material layer 2b is adhered to one surface of the porous layer 2a to form the filter material blank 2.

The porous layer 2a is formed using a porous sheet (hereinafter also referred to as a porous sheet) capable of collecting the particles. The porous sheet is not particularly limited and may be appropriately selected depending on the use of the filter medium 1. For example, a PTFE sheet in which polytetrafluoroethylene (PTFE) is formed into a sheet shape can be used. As a method of 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 liquid lubricant is not particularly limited as long as it can impart appropriate wettability to the surface of the mixture, and particularly preferably can be removed by extraction treatment or heat treatment. For example, a hydrocarbon such as liquid paraffin, petroleum brain or white oil can be used as the liquid lubricant. The amount of the liquid lubricant to be added is not particularly limited. For example, it is preferably 5 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the PTFE fine powder.

Further, the mixture is prepared by molding, and a preliminary molded body is formed. The preliminary forming is preferably carried out under the pressure that the liquid lubricant is not separated by the mixture. Next, the obtained preliminary formed body is formed into a sheet shape by extrusion molding or calender molding. Then, the formed body is made porous by uniaxial stretching or biaxial stretching and a PTFE sheet is formed. Further, the stretching conditions are not particularly limited. For example, in a temperature environment of 30 ° C or more and 400 ° C or less, the stretching ratio is preferably 1.5 times or more and 200 times or less. Further, in the case where the firing step is not performed in the stretching step, it is preferred to fire the PTFE sheet at a temperature equal to or higher than the melting point after the stretching step.

The base material layer 2b is formed using a sheet having gas permeability (hereinafter also referred to as a gas permeable sheet). The gas permeable sheet is not particularly limited, and for example, a nonwoven fabric or a woven fabric, a net, or the like can be used. When the porous layer 2a (porous sheet) and the base material layer 2b (gas permeable sheet) are thermally welded, it is particularly preferable to use a gas permeable sheet having a material having thermoplasticity. For example, synthetic fibers such as polyolefin (polyethylene, polypropylene, etc.), polyamine, polyester, aromatic polyamide, acrylate, polyimide, and the like can be used. In addition, when the gas permeable sheet is composed of one component, the entire gas permeable sheet may be melted and the substrate layer 2b may not be held. Therefore, it is preferable to use a gas permeable sheet having two components having a difference in melting point as a binder. For example, a core PET/PE core sheath fiber, or a PP/PE blended nonwoven fabric or the like can be used as the gas permeable sheet.

The filter material blank 2 is partially formed by adhering the porous layer 2a and the base material layer 2b. That is, the filter material blank 2 includes the adhesive portion 2c which is formed by adhering a part of the porous layer 2a and a part of the base material layer 2b, and the adhesive portion 2c (the porous layer 2a and the base material layer 2b are not adhered). Part of the non-adhesive part 2d. Further, in the adhesive portion 2c, a region (hereinafter also referred to as a pasting region) A1 in which the surfaces of the porous layer 2a and the base material layer 2b are adhered to each other is formed.

The adhesive portion 2c and the adhesive region A1 are formed along the width direction of the filter material blank 2 (in the present embodiment, in a strip shape). Further, the adhesive portion 2c and the adhesive region A1 are continuously formed across substantially the entire width direction of the filter material blank 2. Further, the adhesive portion 2c and the adhesive region A1 are formed in a plurality of intervals along the longitudinal direction of the filter material blank 2. Specifically, the adhesive portion 2c and the adhesive region A1 are formed at positions corresponding to a region (hereinafter, also referred to as a predetermined curved region) A2 which is bent when the filter blank is folded (in more detail, the predetermined curved region is made). The field A2 is located inside the pasting portion 2c). That is, the width of the adhesive portion 2c and the adhesive region A1 is formed to be wider than the width of the predetermined curved region A2. Therefore, when the filter material blank is folded into two, the filter material blank 2 is surely bent inside the respective adhesive portions 2c.

Further, a non-adhering portion 2d is formed between the adjacent adhering portions 2c and 2c. In the non-adhered portion 2d, the porous layer 2a and the base material layer 2b are laminated in a state of being in close contact with each other. Further, the non-adhering portion 2d is configured as a flat plate portion 1b when the filter material blank 2 is formed into a wrinkle shape.

The method of forming the filter material blank 2 as described above is not particularly limited. For example, a hot melt or pressure sensitive type may be disposed between the porous sheet forming the porous layer 2a and the gas permeable sheet forming the base material layer 2b. A method of pressurizing and attaching a porous sheet and a gas permeable sheet. Alternatively, a method of heating the gas permeable sheet to soften it and pressurizing the porous sheet (in other words, a heat buildup layer) may be employed.

The method of pressurizing and adhering the porous sheet and the gas permeable sheet is not particularly limited. For example, one layer of the porous sheet and the gas permeable sheet may be conveyed between a pair of roll members (not shown), and continuously pressurized. A method of attaching a porous sheet and a gas permeable sheet. Alternatively, a method of arranging a monolithic porous sheet and a gas permeable sheet in a laminated state between a pair of sheets (not shown) and intermittently performing pressure adhesion of each of the individual sheets may be employed. .

When a pair of roller members are used to thermally laminate a layer, a pair of roller members composed of a heat roller whose surface temperature is set to the melting point of the gas permeable sheet and a support roller which supports the porous sheet and the gas permeable sheet in the laminated state are used. Therefore, when the porous sheet and the gas permeable sheet are pressure-attached, the gas permeable sheet softens and enters more. The pores of the porous sheet are adhered to the porous sheet and the gas permeable sheet by the anchoring effect to form the adhesive portion 2c and the adhesive region A1.

Further, a method of forming the adhesive portion 2c and the adhesive region A1 at intervals in the longitudinal direction of the filter material blank 2 is not particularly limited. For example, a convex portion may be provided on the surface of the heat roller in the axial direction, and the convex portion may be provided in the convex portion. The porous sheet and the gas permeable sheet are attached to the other roller member in a pressurized manner. Therefore, the gas permeable sheet is softened only at a position in contact with the convex portion of the heat roller, and the porous sheet and the gas permeable sheet are thermally laminated. Therefore, the adhesive portion 2c and the adhesive region A1 are formed at intervals in the longitudinal direction of the filter material blank 2.

The filter material blank 2 configured as described above is bent and folded in each predetermined curved region A2, thereby forming a plurality of curved portions 1a and a plurality of flat plate portions 1b. Next, a holding partition portion 3 is formed between the respective filter material facing surfaces 1c and 1c, and as shown in FIG. 3, the filter medium 1 is formed. The filter medium 1 forms at least a portion of each of the adhesive portions 2c (each pasting region A1) inside the respective curved portions 1a (that is, inside the curved region of the filter material blank 2). Moreover, the substantially central portion in the width direction of the adhesive portion 2c and the adhesive region A1 overlaps with the curved portion 1a, and both end portions of the adhesive portion 2c and the adhesive region A1 in the width direction are overlapped with the flat plate portions 1b and 1b.

Further, the holding partition portion 3 is formed by connecting the round edge portions 3a and 3a which are linearly formed so as to cross the curved portion 1a (that is, the predetermined curved region A2). Specifically, a portion of the rounded edge portion 3a between the pair of filter material opposing faces 1c, 1c is coupled to each other, thereby forming the holding partition portion 3. In the present embodiment, the side surface of the curved portion 1a is partially covered by the rounded edge portion 3a. Therefore, the shape of the curved portion 1a at a position overlapping the rounded edge portion 3a is maintained. shape. For example, by the hot melt adhesive constituting the rounded edge portion 3a, the rounded edge portion 3a is maintained in shape by the shape of the curved portion 1a. Therefore, the shape of the curved portion 1a can be held by the rounded edge portion 3a. Further, the holding partition portion 3 (the portion where the round edge portions 3a and 3a are connected to each other) is the inner side of the range of the filter medium facing surface 1c corresponding to the sticking portion 2c (adhesive region A1). Therefore, the adjacent filter material facing surfaces 1c, 1c are connected to each other through the holding partition portion 3, and the adjacent curved portions 1a, 1a are kept spaced from each other.

The filter medium 1 having the above configuration is disposed such that the flat plate portion 1b intersects with the flow direction of the filtered gas. Therefore, the filtered gas mainly passes through the flat plate portion 1b. That is, in the present embodiment, the filtered gas system mainly passes through the region other than the adhesive portion 2c of the filter medium.

In addition, the filter medium 1 having the above-described configuration may be formed in a state in which the shape (the shape viewed from the side of the curved portion 1a) is formed in a predetermined form, and is placed in a state of being housed in a casing (not shown). The shape of the frame is not particularly limited as long as it can accommodate the filter medium 1, and may be an inner dimension of 1180 mm × 1180 mm, an outer dimension of 1220 mm × 1220 mm, a rectangular parallelepiped having a thickness of 75 mm, or a circular shape having a predetermined inner diameter. Wait for example. Further, the material of the frame is not particularly limited, and aluminum may be used. A caulking agent is filled between the filter medium 1 and the frame. The caulking agent may be a two-liquid epoxy caulking agent (specifically, a Macross 8104MC-18 and a Macroplast UK5400 manufactured by Henkel Co., Ltd.) in a ratio of 3:1.

As described above, according to the filter medium of the present invention and the method for producing the same, the pressure loss can be made relatively low by suppressing the decrease in the gas permeability of the porous layer during the production of the filter medium.

That is, the filter medium 1 prevents the porous layer 2a from being displaced relative to the base material layer 2b when the filter material blank 2 is folded. Specifically, when the filter material blank is folded into two, the predetermined curved region A2 of the filter material blank 2 is displaced in the direction in which the porous layer 2a and the base material layer 2b are oppositely positioned (specifically, along the porous layer). A force is applied to 2a and the direction of the opposing surface of the substrate layer 2b.

However, since at least a portion of the adhesive portion 2c is formed inside the curved portion 1a (i.e., inside the region where the filter material blank 2 is bent), when the filter material blank 2 is folded, the porous material is in the predetermined curved region A2. The relative positional relationship between the layer 2a and the substrate layer 2b is fixed. Therefore, even if a force which causes the relative positional deviation of the porous layer 2a and the base material layer 2b is applied to the predetermined curved region A2 of the filter material blank 2, the positional displacement of the porous layer 2a and the base material layer 2b can be prevented.

Further, since the non-adhesive portion 2d is formed on the flat plate portion 1b, the filter medium 1 having a low pressure loss can be obtained as compared with the case where the adhesive portion 2c is formed on the entire flat plate portion 1b. Specifically, since the porous layer 2a and the base material layer 2b are not adhered to the non-adhesive portion 2d, the hole is not blocked by a part of the base material layer 2b entering the pore of the porous layer 2a, or the porous layer 2a The pores are not blocked by the adhesion of the porous layer 2a and the substrate layer 2b. Therefore, the non-adhesive portion 2d has higher gas permeability than the adhesive portion 2c. Further, the filtered gas passing through the filter medium 1 mainly passes through the flat plate portion 1b of the filter material blank 2. Therefore, since the non-adhesive portion 2d is formed on the flat plate portion 1b, the filter medium 1 has a high gas permeability and a low pressure loss as compared with the case where the adhesive portion 2c is formed on the entire flat plate portion 1b. Filter material 1. Pressure loss can be measured using a constant pressure gauge (minimum scale: 1.0 Pa), or an electrical micro differential pressure gauge (fine Degree: 1.0 Pa).

Further, when the filter material blank 2 is bent into a corrugated shape, the predetermined curved region A2 is formed in the width direction of the adhesive portion 2c. Therefore, even if the predetermined curved region A2 is displaced from the desired position, the filter material blank 2 may be It is surely bent inside the adhesive portion 2c. Therefore, at least a portion of the adhesive portion 2c can be surely formed inside the curved portion 1a (i.e., inside the curved region of the filter material blank 2).

Moreover, by forming the adhesive portion 2c in the curved portion 1a of the filter material blank 2, it is possible to suppress the filter medium having low gas permeability due to the influence of the adhesive portion 2c. Specifically, although the gas permeability of the adhesive portion 2c is lowered as described above, since the filter material blank 2 is in a curved state, the gas permeability of the curved portion 1a becomes lower than that of the flat plate portion 1b. In other words, the adhesive portion 2c which is inferior in the gas permeability is formed on the curved portion 1a which is low in permeability and can be easily used as a filter material, thereby suppressing the gas permeability of the flat portion 1b which can effectively function as a filter medium. The adhesive portion 2c is lowered.

Further, the holding partition portion 3 is followed by the inner side of the region corresponding to the pasting portion 2c of each of the filter material facing faces 1c, whereby a portion of the attaching portion 2c is formed to be spaced apart from the one side of the retaining portion 3 on the other hand side. The area of the flat portion 1b between the portions 3. Therefore, on the one hand, the side holding spacer 3 and the other side holding spacer 3 are separated in the direction of the direction of the arrow X and the arrow Y, and the spacer 3 and the other side are located on the one hand side. A part of the adhesion portion 2c between the spacers 3 is maintained, and the adhesion state between the porous layer 2a forming the flat plate portion 1b and the base material layer 2b can be maintained. Therefore, the porous layer 2a and the base material layer 2b can be prevented from being pulled apart, and the porous layer 2a and the base can be suppressed. A space is formed between the material layers 2b to increase the pressure loss of the filter media.

Further, in the present embodiment, the side holding partition portion 3 and the other side holding spacer portion 3 are superposed on each other through the flat plate portion 1b. Therefore, when the filter medium 1 is elongated in the extending direction, the spacer is held by the one side. 3, and the spacer 3 is held on the other side, and the flat plate portion 1b (specifically, the filter material blank 2 constituting the flat plate portion 1b) can be prevented from being peeled off and damaged on one surface side and the other surface side.

Further, the filter medium of the present invention and the method for producing the same are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Further, of course, the configuration or method of the above-described plurality of embodiments may be arbitrarily used (the configuration or method of one embodiment may be used in another embodiment or the like), and the following may be arbitrarily selected. The configuration, method, and the like of various modified examples are the same as those of the above-described embodiments.

For example, in the above embodiment, the adhesive portion 2c is continuously formed across the entire width direction of the filter blank 2, but is not limited thereto. For example, as shown in Fig. 5(a), the adhesive portion 2e may be along the filter blank. The width direction of the material 2 is intermittently formed.

Further, in the above-described embodiment, the rounded edge portion 3a is formed to intersect the curved portion 1a. However, the present invention is not limited thereto. For example, as shown in FIG. 5(b), only the holding spacer 3' may be formed. Part of the formation of the rounded edge portion 3b.

In the above-described embodiment, the holding partition portion 3 is formed in a plurality of intervals in the longitudinal direction of the curved portion 1a. However, the present invention is not limited thereto, and may be integrally formed along the longitudinal direction of the curved portion 1a. Moreover, in the above embodiment In the meantime, the holding partition portion 3 is formed on the inner side of the region corresponding to the adhesive portion 2c in the filter material facing surface 1c. However, the present invention is not limited thereto, and the holding partition portion 3 may be formed by the inner side of the region across the outer side.

Further, in the above embodiment, the width of the adhesive portion 2c is formed to be wider than the width of the predetermined curved region A2. However, the width of the adhesive portion 2c may be narrower than the width of the predetermined curved region A2.

Further, in the above-described embodiment, the filter material blank 2 is bent at a plurality of positions in the width direction. However, the present invention is not limited thereto, and the center portion of the single-piece filter material blank may be radially bent at a plurality of positions to form a conical shape. Filter media.

Further, in the above-described embodiment, the filter medium 1 composed of the porous layer 2a and the base material layer 2b is used to constitute the filter medium 1, but the filter medium 1 is not limited thereto. For example, the base may be adhered to both sides of the porous layer 2a. The filter material of the layer 2b constitutes a filter medium.

Example

Hereinafter, embodiments of the invention will be described.

<Example 1>

Porous sheet

A porous sheet was used for the porous sheet. Specifically, a mixture of 19 parts by weight of a liquid lubricant (n-decane) was added to 100 parts by weight of a PTFE fine powder (trade name: F104, manufactured by Daikin Industries Co., Ltd.) to prepare a paste. Next, after preparing the mixture, the sheet-shaped formed body having a long direction in one direction is obtained by extrusion molding. Then, the flat shaped body was calendered so as to have a thickness of 0.2 mm. Next, in order to remove the liquid from the flat shaped body The lubricant was heated at 150 ° C in a drying oven. Then, the flat shaped body was stretched 15 times in the longitudinal direction in an environment of 280 ° C, and extended to 15 times in the width direction orthogonal to the longitudinal direction in an environment of 100 ° C to obtain a PTFE sheet.

2. Breathable sheet

A PET/PE core-sheath fiber nonwoven fabric (trade name: T1003WDO, manufactured by UNITIKA Co., Ltd.) formed in a long direction was used as a gas permeable sheet.

3. Production of filter material

The porous sheet and the gas permeable sheet are conveyed between the pair of roller members (the heat roller and the support roller) while being substantially parallel to each other in the longitudinal direction of the porous sheet. The porous sheet and the gas permeable sheet were adhered to prepare a filter material blank 2 as shown in FIG. Specifically, a convex portion is formed on the surface in the axial direction as a heat roller, and a porous sheet and a gas permeable sheet are thermally laminated only between the convex portion and the support roller to form the adhesive portion 2c. Further, as the roller member, an outer diameter of 200 mm was used. Further, the conveying speed of each sheet was 10 m/min, and the pressure at the time of sticking was 0.8 MPa.

The adhesive portion 2c of the filter material blank 2 is formed integrally and integrally formed in a strip shape across the both end portions in the width direction of the filter material blank 2. Further, the width of the adhesive portion 2c was 2 cm, and the interval between the central portions of the adjacent adhesive portions 2c in the width direction was 5 cm. Further, the thickness of the adhesive portion 2c is 0.32 mm, and the thickness of the non-adhered portion 2d is 0.45 mm.

4. Measurement of pressure loss

The resulting filter blank 2 was used to measure the pressure loss. Specifically, the pressure loss when the effective area was measured to be 100 cm ² and the surface speed was 5.3 cm/sec was measured using a constant pressure meter (minimum scale: 1.0 Pa). The measurement results are shown in Table 1 below.

5. Evaluation of processability during folding processing

The filter material blank 2 is folded, and the curved portion 1a is formed inside the adhesive portion 2c of the obtained filter material blank 2, and as shown in Fig. 1, the rounded edge portion 3a (using MACROMELT6202 manufactured by Henkel Co., Ltd. as an adhesive) is formed. The filter medium 1 is prepared by holding the spacer 3 . The height of the mountain during the folding process is 50mm. The mountain height refers to the interval between the mountain side surface of the curved portion 1a formed on one surface side of the filter material blank 2 and the central portion of the mountain side surface of the curved portion 1a formed on the other surface side, that is, the central portion along the filter material blank 2 The interval in the direction of the thickness direction. The evaluation of the folding processability was "○" when the folding process was favorably performed, and "x" when the folding process was not performed satisfactorily. The evaluation results are shown in Table 1 below.

<Comparative Example 1>

The filter material blank 2 was produced in the same manner as in Example 1 except that the interval between the central portions of the adjacent adhesive portions 2c in the width direction was 6.5 cm, and the pressure loss was measured using the filter material blank 2 under the same conditions. In addition, the workability of the folding process was evaluated under the same conditions as in Example 1 except that the bent portion 1a was formed in a portion other than the adhesive portion 2c of the obtained filter material blank 2. The measurement results of the pressure loss and the evaluation results of the workability of the folding process are shown in Table 1 below.

<Comparative Example 2>

The same as in the first embodiment except that the adhesive layer 2c is formed integrally on the opposite side of the porous sheet and the gas permeable sheet. Method The filter blank 2 was made and the filter loss was measured using the filter blank 2 under the same conditions. Further, using the obtained filter material blank 2, the workability of the folding process was evaluated under the same conditions as in Example 1. The measurement results of the pressure loss and the evaluation results of the workability of the folding process are shown in Table 1 below.

<summary>

When the first embodiment was compared with the comparative example 1, it was confirmed that the workability of the folding process of the first embodiment was excellent. This is because, when the folding process is performed, a force for shifting the relative positional relationship between the porous sheet and the gas permeable sheet is applied to the predetermined curved region A2, but as shown in the embodiment 1, a predetermined curvature is formed inside the adhesive portion 2c. In the region A2, the relative positional relationship between the porous sheet and the gas permeable sheet is fixed in the predetermined curved region A2, so that the occurrence of the above-described offset can be prevented, and the folding processing can be favorably performed. Further, it was confirmed that the pressure loss of Comparative Example 1 was lower than that of Example 1. This is because the interval 2 of forming the adhesive portion 2c is relatively wide, and the area of the non-adhered portion 2d is larger than that of the first embodiment.

Further, in comparison between Example 1 and Comparative Example 2, it was confirmed that the pressure loss in Example 1 was relatively low. This is because, as shown in the first embodiment, when a plurality of the adhesive portions 2c are formed at intervals, a non-adhering portion 2d is formed between the adhesive portions 2c. In the non-adhered portion 2d, the pores of the porous sheet are not partially blocked by the melted gas-permeable sheet due to the heat build-up, so that the porous portion can be maintained in the non-adhered portion 2d. The breathability of the film. Therefore, the pressure loss can be reduced as compared with the case where the adhesive portion 2c is formed over the entire area of the filter material blank 2.

Claims (4)

A filter medium is formed by bending a filter material billet at a plurality of positions to form a wrinkle, and the filter material has a porous layer that collects particles contained in the filter gas, and adheres to at least the porous layer. a substrate layer on one side; the filter medium is characterized in that: the curved portion is formed by bending the blank of the filter material and forming in one direction; and the flat portion is formed into a plate shape other than the curved portion of the filter material Further, at least a portion of the adhesive portion adhered to the porous layer and the substrate layer is formed inside the curved portion, and the non-adhesive portion of the unbonded porous layer and the substrate layer is formed on the flat plate unit. The filter medium according to claim 1, wherein the adhesive portion is formed in a strip shape along the curved portion, and the bent portion is formed inside the width direction of the adhesive portion. A filter medium according to claim 1 or 2, further comprising a holding partition that keeps the adjacent curved portions spaced apart from each other, and the holding spacer is configured to be subsequently formed when the filter material is bent into a wrinkle shape The pair of opposing faces are joined to the inner side of the region corresponding to the pasting portion of the pair of opposing faces. A method for producing a filter medium is characterized in that a filter material is bent at a plurality of positions to form a wrinkle shape, thereby forming a filter medium, and the filter material is collected in a porous layer of particles contained in the filtered gas. a method of adhering a substrate layer to one of the lesser layers; the method is characterized in that, when the blank of the filter material is bent to form a curved portion in one direction, at least the adhesive portion of the porous layer and the substrate layer is adhered A portion is formed on the inner side of the curved portion to form a curved portion, and the non-adhesive portion of the non-adhesive porous layer and the base material layer is formed on the flat plate portion, and the flat plate portion is other than the curved portion of the filter material blank The area is formed into a plate shape.