JP6912874B2 - Filter packs, air filters, filter pack manufacturing methods, and air filter manufacturing methods - Google Patents

Description

The present invention relates to a filter pack, an air filter, a method for manufacturing a filter pack, and a method for manufacturing an air filter.

The filter medium that collects the fine particles in the gas may be pleated in order to increase the area of the filter medium when it is made into an air filter. The pleated filter medium (hereinafter, simply referred to as a filter medium) has a plurality of mountain-folded peaks and a plurality of valley-folded valleys. The pleated spacing is maintained by using a spacing member so that the flat surface extending between the valleys does not come into contact with other adjacent flat surfaces. As a result, the flow path of the gas passing through the filter medium is secured, the increase in the pressure loss of the air filter is suppressed, and the dust retention amount is secured by securing the filtration area, and the decrease in the life is suppressed. ..
Conventionally, as an interval holding material, a resin is known to be bridged over the mountain parts so as to be in contact with each apex of the mountain parts in the direction in which the mountain parts are lined up. This type of spacing holding material is formed by heating and melting a thermoplastic resin called a hot melt resin, for example, by directly applying it to a filter medium (hereinafter, also referred to as a direct method).
Further, as the interval holding material of the above type, a hot melt resin heated and melted is applied to, for example, in a groove on the upper surface of a jig extending linearly, and the jig is turned upside down to form a pile of filter media. It is formed by transferring the hot melt resin (hereinafter, also referred to as a transfer method) by placing it so as to span the portion (Patent Document 1).

Jikkai Sho 62-62222

In the direct method, the resin that is the part between the peaks may hang down to the side of the valley. If the resin hangs down and adheres to the flat surface of the filter medium, the filtration area when the filter medium is used as an air filter is reduced, which may lead to a decrease in filter performance such as an increase in pressure loss and a decrease in dust retention. ..
On the other hand, in the transfer method, it was found that even if the resin is transferred to the filter medium, the resin may not adhere well to the filter medium and may fall off.

An object of the present invention is to provide a filter pack and an air filter in which the sagging of the spacing material is suppressed and the spacing material is well adhered to the filter medium. Another object of the present invention is to provide a method for manufacturing such a filter pack and a method for manufacturing an air filter.

One aspect of the present invention is a filter pack.
A pleated filter medium that collects fine particles in gas,
A space-holding material for holding the pleated space of the filter medium is provided.
The filter medium is arranged on the first side of the direction of the airflow passing through the filter medium, and has a plurality of mountain folds and a second side opposite to the first side and the direction of the airflow. It has multiple valleys, which are arranged on the side and folded in valleys,
The spacing material extends along the direction in which the peaks are lined up on the first side, and is bridged over the peaks so as to be in contact with the respective vertices of the peaks, and is polyamide-based, polyurethane-based, or polyolefin. It is a type of resin and consists of a thermoplastic resin with a softening point of 150 to 180 ° C.
Along the direction of the air flow between the apex of the mountain portion and the end of the second side recessed to the second side of the portion of the spacing material between the two adjacent mountain portions. The ratio D / S of the interval D to the interval S of the two peaks is 0 to 30%.

The filter medium has an embossed protrusion that projects to the first side on each of the flat surfaces that extend between the peak and the valley at an angle with respect to the direction of the air flow. Then, the protrusions of the two flat surfaces extending from the valley are formed at positions where they are in contact with each other.
It is preferable that the spacing member is arranged at the same position as the protrusion in a direction parallel to the direction in which the crease of the mountain portion extends.

Another aspect of the present invention is an air filter.
With the filter pack
It is characterized by including a frame body for holding the filter pack.

Another aspect of the present invention is a method for manufacturing a filter pack.
A step of pleating a filter medium sheet that collects fine particles in a gas to prepare a filter medium, and
A step of forming an interval holding material for holding the pleated interval of the filter medium on the filter medium is provided.
In the step of producing the filter medium, the plurality of mountain portions arranged on the first side of the direction of the airflow passing through the filter medium, and the first side and the opposite side of the direction of the airflow. A plurality of valleys, which are arranged on a second side and are valley-folded, are formed.
In the step of forming the spacing material, a thermoplastic resin which is a polyamide-based, polyurethane-based, or polyolefin-based resin and has a softening point of 150 to 180 ° C. is arranged so as to extend in one direction without contacting the filter medium. Then, the arranged thermoplastic resin is brought into contact with the filter medium so as to be in contact with each apex of the mountain portion along the direction in which the mountain portions are lined up on the first side.

Another aspect of the present invention is a method for manufacturing an air filter.
The process of manufacturing the filter pack according to the method of manufacturing the filter pack, and
It is characterized by including a step of holding the filter pack in a frame.

According to the present invention, it is possible to obtain a filter pack and an air filter in which the sagging of the space-holding material is suppressed and the space-holding material is well adhered to the filter material.

It is an external perspective view which shows the filter pack of this embodiment by cutting out a part. It is a side view which shows the upstream part of the filter pack shown in FIG. 1 as seen in the fold direction of the pleats. It is external drawing of the filter medium explaining the protrusion. It is a developed view of the filter medium explaining the arrangement of the protrusions. It is a figure which shows the air filter of this embodiment. It is a figure explaining the transfer method.

Hereinafter, the filter pack, the air filter, the method for manufacturing the filter pack, and the method for manufacturing the air filter of the present embodiment will be described.

FIG. 1 is an external perspective view showing the filter pack 10 of the present embodiment. In FIG. 1, a part of the filter pack 10 is cut out.
The filter pack 10 includes a filter medium 3 and an interval holding material 5.

The filter medium 3 is a member that collects fine particles in a gas and is pleated.
The filter medium 3 is used for removing dust having a particle size of 2.5 μm or less and a concentration of 0.3 mg / m ³ or less, and has a collection efficiency of 80% or more by a counting method, a pressure loss of 79 to 493 Pa, and dust retention. Those having a capacity (dust retention amount) of 200 to 800 g / m ³ are used. In the counting method, particles of atmospheric dust, polyalphaolefin (PAO), or silica having a particle size of 0.3 μm are used. The dust holding capacity is the amount of dust collected by the filter before reaching a predetermined final pressure loss.

As the filter medium 3, for example, a non-woven fabric or a woven fabric made of a fiber material of glass fiber or resin fiber is used. Specific examples of the filter medium 3 include those provided with a collecting layer and a reinforcing layer (both not shown) described below.
The collection layer is made of a non-woven fabric made of resin fibers. As the non-woven fabric, for example, a melt-blown non-woven fabric can be used. In the melt blow nonwoven fabric, for example, the molten resin composition is extruded into a fine resin stream, and the resin stream is brought into contact with a high-speed heating gas to form a discontinuous fiber having a fine fiber diameter, and this fiber is formed on a porous support. It is formed by accumulating in. The basis weight of the melt-blown non-woven fabric is 5 to 100 g / m ² , preferably 10 to 80 g / m ² . The fiber diameter is 0.1 to 10 μm, preferably 1 to 6 μm, and the average fiber length is 50 to 200 mm, preferably 80 to 150 mm.

Examples of the material of the melt blown non-woven fabric include ethylene-based copolymers such as polyethylene, ethylene-propylene copolymer, ethylene-butylene copolymer, and ethylene-octene copolymer, and polyolefins such as polypropylene or propylene copolymer and polybutylene. , 6-Nylon, 66-Nylon, 6,66 Copolymerized Nylon, 610-Nylon, 11-Nylon, 12-Nylon and other polyamides or copolymerized polyamides, polyethylene terephthalates, ethylene terephthalate copolymers, polybutylene terephthalates and other polyesters. , At least one polymer selected from aliphatic polycarbonate, polyurethane elastomer, polyvinyl chloride or copolymer, total aromatic polyester, polyphenylene sulfide and the like. Of these, polypropylene is preferable because it has excellent melt-blow moldability, is low in cost, and has an extremely low possibility of mixing of non-fibrous polymer balls called shots during the production of the melt-blow non-woven fabric.

The reinforcing layer is a sheet having higher rigidity and higher air permeability than the collecting layer. As the reinforcing layer, one that is easily deformed, has a thin thickness, and is light is preferably used. As the reinforcing layer, a woven fabric or non-woven fabric made of a synthetic resin such as paper, polyethylene terephthalate, or nylon, a net, or the like can be used. As the non-woven fabric, for example, a thermal bond non-woven fabric can be used. When the collecting layer is a melt-blown non-woven fabric, the non-woven fabric of the reinforcing layer is preferably a thermal-bonded non-woven fabric. As the thermal bond non-woven fabric, known ones can be used without particular limitation, and for example, one in which a fleece having a low melting point is passed through between hot rolls and pressure-bonded is used. Examples of the material of the thermal bond non-woven fabric include polyester, polypropylene, and polyamide. In this embodiment, polyester is used. The thermal bond non-woven fabric may be one that is pressure-bonded by applying hot air.

The reinforcing layer may be laminated on one side or both sides of the collection layer. The method of laminating the collection layer and the reinforcing layer is not particularly limited, and for example, a method of bonding the two layers using an adhesive or a method of collecting on a reinforcing layer manufactured by a manufacturing method other than the melt blow method is performed by the melt blow method. Laminating layers can be mentioned.

The above-mentioned collecting layer and reinforcing layer may be electret-treated. The electret treatment is performed by applying a DC voltage to the non-woven fabric. The value of the applied DC voltage is, for example, when the distance between the electrodes is 8 mm, it is performed by applying a DC voltage of 5 kV or more, preferably 6 to 20 kV, to the non-woven fabric.
The filter medium 3 may carry an antibacterial agent, an antifungal agent, or the like.

The filter medium 3 has a zigzag shape in which a filter medium sheet is pleated and mountain folds and valley folds are alternately performed so that a plurality of mountain portions 3a and valley portions 3b are formed. Pleat processing is performed using a reciprocating or rotary folding machine. When the filter medium 3 is used as an air filter (described later), the mountain portion 3a is located on the upstream side (first side) of the direction of the airflow passing through the filter medium 3 (the X direction in FIGS. 1 and 2; hereinafter referred to as the airflow direction). ), And the valley portion 3b is arranged on the downstream side (second side) in the airflow direction. When the upstream side portion and the downstream side portion of the filter medium 3 are inverted, the mountain portion 3a can be regarded as a valley portion and the valley portion 3b can be regarded as a mountain portion. That is, the mountain part 3a when viewed from the upstream side becomes a valley part when viewed from the downstream side.

The crease spacing (pleated spacing) of the adjacent mountain portions 3a of the filter medium 3 is, for example, 1 to 10 mm, preferably 2 to 7 mm. The crease spacing of the mountain portion 3a is equal to the crease spacing of the adjacent valley portion 3b.
The number of pleats of the filter medium 3 is, for example, 5 to 30 per 100 mm of the width (length along the Y direction of FIGS. 1 and 2) of the filter pack 10. The filter medium 3 has a flat surface portion 3c extending between the mountain portion 3a and the valley portion 3b so as to be inclined with respect to the airflow direction, and the width of the flat surface portion 3c (the apex of the mountain portion 3a in the XY plane). The length along the direction connecting the valley portion 3b and the lowest point of the valley portion 3b (also referred to as a folding width) is, for example, 20 to 150 mm, preferably 50 to 130 mm.

As shown in FIGS. 2 to 4, the filter medium 3 has embossed protrusions 1A, 1B, 1C, 1D, and 1E protruding upstream on each of the flat surface portions 3c, and has one valley portion 3b. It is preferable that the protrusions 1A to 1E of the two flat surfaces 3d extending from the above are formed at positions where they are in contact with each other. FIG. 2 is a side view showing the upstream portion of the filter pack shown in FIG. 1 as viewed in the fold direction of the pleats. FIG. 3 is an external view of a filter medium for explaining a protrusion. FIG. 4 is a developed view of a filter medium for explaining the arrangement of the protrusions.
When the filter media 3 is folded, the protrusions 1A to 1E keep the pleated spacing of the filter media 3 and maintain the zigzag shape of the filter media 3 when the protrusions 1A to 1E facing each other come into contact with each other. "Protruding to the upstream side" means that the projecting direction of the protrusion 1 projected in the airflow direction faces the upstream side. The filter medium 3 preferably has another protrusion protruding downstream, as shown in FIGS. 3 and 4, in each of the plane portions 3c, and extends from one mountain portion 3a. It is preferable that the other protrusions of the two flat portions 3c are formed at positions where they are in contact with each other. That is, it is preferable that protrusions are formed on both the front and back surfaces of the filter medium 3. "Protruding to the downstream side" means that the projecting direction of the protrusion 1 projected in the airflow direction faces the downstream side. With respect to the filter medium 3, the protrusions 1A to 1E protruding toward the front side (upstream side) in FIGS. 3 and 4 are convex protrusions, and the protrusions 1A to 1E protruding to the opposite side (downstream side) are concave protrusions. .. That is, the concave protrusion when viewed from one surface of the filter medium 3 becomes a convex protrusion when viewed from the other surface.

The protrusions 1A to 1E are manufactured by an apparatus using a roll-shaped embossed type or a flat plate-shaped embossed type.
The contour shape of the protrusions 1A to 1E can be selected from various shapes such as a rectangular parallelepiped, a cube, a prism, a cylinder, a hemisphere, a spherical band, a pedestal, a cone, a pyramid, and a truncated cone. Further, the protruding portions facing each other do not necessarily have the same contour shape.

The height of the protrusions 1A to 1E is preferably 0.5 mm to 5.0 mm, and more preferably 1.5 mm to 4.0 mm. If the height is higher than 5.0 mm, the filter medium 3 may be damaged during embossing. If the height is lower than 0.5 mm, it becomes difficult to maintain the spacing between the filter media 3. Further, the number of protrusions 1A to 1E to be arranged is not particularly limited as in the shape and dimensions.
Further, the heights of the protrusions 1A to 1E are the lowest at the innermost part (valley bottom) of the folded valley portion 3b, and by gradually increasing the height of the protrusions, the protrusions 1A to 1E The shape of the filter medium 3 can be stably held in a zigzag shape without an excessive force acting on the filter medium 3. In the example shown in FIG. 3, the height of the protrusion 1E, which is a convex protrusion, is the lowest, the height of the protrusion 1A is the highest, and the protrusions 1A to 1E are formed so that the height gradually changes between them. ing.
In the following description, when the protrusions 1A to 1E are collectively described, 1 is used as the reference numeral of the protrusions.

The spacing member 5 is a member that holds the pleated spacing of the filter media 3. When the filter medium 3 has the protrusion 1, the pleated space is maintained together with the protrusion 1.
As shown in FIG. 2, the interval holding member 5 extends along the direction in which the mountain portions 3a are lined up on the upstream side (Y direction in FIGS. 1 and 2), and the mountain portions are in contact with the respective vertices of the mountain portions 3a. It is bridged over 3a.

The form of the interval holding material 5 is selected from a string-like shape, a band-like shape, and the like. The spacing member 5 has a string shape in the examples shown in FIGS. 1 and 2. When the spacing member 5 has a string shape, its thickness is, for example, 1 to 10 mm. As shown in FIG. 2, in the interval holding material 5, for example, 0 to 2 mm is arranged on the downstream side of the apex of the mountain portion 3a, whereby the adhesive force with the filter material 3 is enhanced. Further, the spacing member 5 is arranged, for example, about 1 to 6 mm on the upstream side of the apex of the mountain portion 3a, and thereby functions as a support having strength in the direction in which the mountain portions 3a are lined up. In FIG. 2, the length of the portion downstream from the apex of the mountain portion 3a and the length of the portion upstream of the apex of the mountain portion 3a are exaggerated.

The spacing member 5 may be provided only on the upstream side of the filter medium 3, or may be provided on both the upstream side and the downstream side of the filter medium 3. One spacing member 5 is provided on each of the upstream side and the downstream side, or a plurality of spacing members 5 are provided in parallel with each other. When a plurality of the spacing members 5 are provided, the spacing between the spacing members 5 is, for example, 25 to 100 mm.

The interval holding material 5 is made of a thermoplastic resin having a softening point of 130 to 180 ° C. In the present specification, the softening point means a softening point measured in accordance with JIS K6863: 1994. When the softening point is within the above range, even when the thermoplastic resin (hereinafter, also simply referred to as resin) is indirectly applied (transferred) to the filter medium, the sagging of the spacing holding material 5 is suppressed and the spacing is suppressed. The holding material 5 is well adhered to the filter material 3. The thermoplastic resin applied to the filter medium 3 is preferably cured quickly in order to prevent it from hanging down to the valley portion 3b side. The transfer method is effective in suppressing sagging because the thermoplastic resin is appropriately cooled by coming into contact with the jig. In the transfer method, generally, a thermoplastic resin is applied into a groove on the upper surface of a jig extending linearly, and the resin is transferred by being placed upside down and placed over a mountain portion 3a of a filter medium 3. .. However, experience has shown that the transferred thermoplastic resin may not adhere well to the filter medium 3. Here, when the jig is heated and transferred, the transferred thermoplastic resin may hang down. The present inventor indirectly applied the thermoplastic resin to the pleated filter medium 3 by using a jig by using a thermoplastic resin having a softening point in the above range as the resin for the interval holding material. It has been found that the thermoplastic resin adheres well to the filter medium 3 even in the case. It was also found that the D / S described later can be set to 0 to 30%.

When the softening point of the thermoplastic resin is 180 ° C. or lower, the time from melting the resin to curing is longer than when transfer is performed under the same conditions using a thermoplastic resin having a softening point of more than 180 ° C. Therefore, it is considered that the thermoplastic resin is satisfactorily adhered to the filter medium 3. In addition, it is possible to secure a working time for transferring the thermoplastic resin to the filter medium 3. In addition, curing means that the thermoplastic resin is not deformed by the tactile finger, for example. When the softening point of the thermoplastic resin exceeds 180 ° C., the time from melting the thermoplastic resin to curing becomes short, and the thermoplastic resin does not adhere well to the filter medium 3. Further, since the thermoplastic resin is heated to a high temperature to melt it, the filter medium 3 may be damaged when the resin is transferred. In particular, when the temperature difference from the melting point of the fiber material constituting the filter medium 3 is large, the damage to the filter medium 3 becomes remarkable.
Further, when the softening point of the thermoplastic resin is 130 ° C. or higher, it is possible to prevent the resin from hanging down until it is cured. Further, the time from melting the thermoplastic resin to curing is not too long, and the decrease in the productivity of the filter pack 10 can be suppressed. If the softening point of the thermoplastic resin is less than 130 ° C., the resin transferred to the filter medium 3 may hang down.
The softening point of the thermoplastic resin is preferably 140 to 170 ° C, more preferably 150 to 160 ° C.

The thermoplastic resin is preferably a polyamide-based, urethane-based, olefin-based, or polyolefin-based resin.
The viscosity of the thermoplastic resin is preferably 300 to 9500 mPa · s. The viscosity referred to here refers to the melt viscosity measured in accordance with JIS K6862: 1984. The viscosity of the thermoplastic resin is more preferably 350 to 6000 mPa · s, and particularly preferably 400 to 3000 mPa · s. When the viscosity of the thermoplastic resin is in the above range, it becomes easy to secure workability while suppressing sagging when transferred to the filter medium 3. In addition, the D / S described later can be reduced.

The thermoplastic resin preferably has flame retardancy depending on the use of the air filter. Examples of such applications include air filters used in nuclear facilities including nuclear power plants. The air filter used in a nuclear facility is, for example, an air filter that produces air supplied to a human work space by filtration. In such an air filter, it is preferable from the viewpoint of safety that all the components of the air filter including the spacing member 5 have flame retardancy or nonflammability. The flame retardancy here means, for example, a flame retardancy having a height of UL (Underwriters Laboratories, Inc) 94 V-0 or higher.

As shown in FIG. 2, of the apex a of the mountain portion 3a and the downstream end of the portion of the spacing member 5 between the two adjacent mountain portions 3a, the end b recessed to the most downstream side. The ratio D / S of the interval D along the airflow direction to the interval (pleated interval) S of the two peaks 3a is preferably 0 to 30%. Since the interval holding material 5 in which the D / S satisfies the above range has a suppressed amount of sagging in the airflow direction (interval D), a decrease in the filtration area when an air filter is used can be suppressed. The interval holding material 5 whose D / S satisfies the above range can be formed by using a thermoplastic resin having a softening point in the above range. As the interval D, of the intervals between all the mountain portions 3a included in one interval holding material 5, for example, the average of the measured values for 10 or more randomly selected pleated intervals may be used. can.

It is preferable that the spacing member 5 is arranged at the same position as the protrusion 1 in the direction parallel to the direction in which the crease of the mountain portion 3a extends (Z direction in FIG. 1). By arranging in this way, the area of the region that blocks the gas flowing in the airflow direction is minimized in the plane (YZ plane in FIG. 1) orthogonal to the airflow direction, and the pressure loss is caused by the turbulence of the airflow. Is suppressed from rising.

The filter pack 10 can be manufactured by the method for manufacturing a filter pack described later.

In the above filter pack 10, since the space-holding material 5 is made of a thermoplastic resin having a softening point of 130 to 180 degrees, the gap-holding material 5 is suppressed from hanging down, and the space-holding material 5 is used as the filter material 3. It is well adhered.

FIG. 5 shows an external perspective view of the air filter 30 of the present embodiment.
The air filter 30 includes a filter pack 10 and a frame body 20 for holding the filter pack 10. The frame body 20 is made by combining, for example, a frame material such as a zinc iron plate, a stainless steel plate, or a resin. In the filter pack 10, both ends in the direction in which the folds of the pleats extend (Z direction) are fixed to the frame body 20 with, for example, a urethane resin sealant, and both ends in the direction in which the mountain portions 3a are lined up (Y direction) are adhered to each other. It is fixed by being line-bonded with an agent. Line bonding is bonding along the direction in which the folds of the pleats extend (Z direction).
The air filter 30 can be manufactured by the method for manufacturing an air filter described later.

The air filter 30 has, for example, the performance of a medium performance filter or a HEPA (High Efficiency Particulate Air) filter. The medium-performance filter is an air filter having a medium particle collection rate mainly for particles having a particle size smaller than 5 μm, and has a collection efficiency of 50 to 95% by a light scattered light amount integration method (colorimetric method). Or, it is an air fill having a collection efficiency of 5 to 90% by a counting method (particle size 0.3 μm). The HEPA filter is a filter having a collection efficiency of 99.97% or more with respect to particles having a particle size of 0.3 μm at a rated air volume, and an initial pressure loss of 245 Pa or less.

Next, a method for manufacturing the filter pack and the method for manufacturing the air filter of the present embodiment will be described.
The method for producing a filter pack includes a filter medium manufacturing step and an interval holding material forming step.

In the filter medium preparation step, a filter medium sheet that collects fine particles in a gas is pleated to prepare a filter medium. In the step of producing the filter medium 3, a plurality of mountain portions 3a formed by mountain folding and a plurality of valley portions 3b formed by valley folding and connected to each of the two adjacent mountain portions 3a are formed. Specifically, in the step of producing the filter medium, the filter medium 3 described above is produced.

In the interval holding material forming step, the interval holding material 5 for maintaining the pleated interval of the filter medium 3 is formed on the filter medium 3. In the step of forming the spacing member 5, the thermoplastic resin is arranged so as to extend in one direction, and the thermoplastic resin arranged in this way is placed along the direction in which the mountain portions 3a are lined up on the upstream side. It is arranged so as to be in contact with each apex of the above, that is, transfer is performed.
Specifically, the resin is heated and melted, and as shown in FIG. 6, it is applied into the groove 40a of the jig 40 extending in one direction. In the transfer method, the thermoplastic resin is heated to a temperature higher than the softening point of the thermoplastic resin (for example, 220 to 240 ° C.) to be melted, and the thermoplastic resin is applied into the groove 40a formed on the upper surface of the jig 40. FIG. 6 is a diagram illustrating the formation of the spacing member 5 using the transfer method. The groove 40a has a linear shape extending in one direction. The cross-sectional shape of the groove 40a in the direction orthogonal to the extending direction is, for example, a semicircle. The jig 40 is used at room temperature, but a heated jig 40 may be used as long as the transferred resin does not hang down. Further, the width of the filter medium 3 created in the filter medium preparation step in the direction in which the mountain portions 3a are lined up is kept constant. Next, the jig 40 coated with the thermoplastic resin is turned upside down and placed on the mountain portion 3a of the filter medium 3, and the thermoplastic resin on the lower surface side of the jig 40 is placed on the apex of the mountain portion 3a. Make contact. After applying the thermoplastic resin to the jig 40, for example, after a predetermined time (for example, about 5 to 20 seconds) has elapsed in order to adjust the viscosity of the thermoplastic resin, the jig 40 is directed downward so that the groove 40a faces downward. Is transferred by turning it upside down and placing it on the filter medium 3. After transfer, it is allowed to cure at room temperature for a predetermined time (for example, 60 to 120 seconds).

According to the above method for manufacturing a filter pack, the space-holding material 5 can be satisfactorily adhered to the filter material 3 while suppressing the sagging of the space-holding material 5. For example, even when the interval holding material 5 is used for the filter medium 3 having a wide pleated interval (8 to 15 mm), the sagging of the interval holding material 5 can be suppressed.

The method for manufacturing an air filter includes a step of manufacturing a filter pack and a step of holding the filter pack in a frame.

In the step of manufacturing the filter pack, the filter pack 10 is manufactured according to the method for manufacturing the filter pack described above. In the step of holding the filter pack in the frame body, the filter pack 10 manufactured in the step of manufacturing the filter pack is held in the frame body 20 prepared in advance by combining the frame materials. Specifically, both ends of the filter pack 10 in the direction in which the pleats extend (Z direction) are fixed to the frame 20 with, for example, a urethane resin sealant, and both ends in the direction in which the mountain portions 3a are lined up (Y direction) are fixed. , It is fixed to the frame 20 by line-bonding with an adhesive.
Instead of the method described above, the air filter may be manufactured by holding the filter medium 3 on the frame body 20 and then forming the interval holding material 5.

(Example)
The filter medium sheet was prepared by laminating a collecting layer made of a polypropylene melt blown non-woven fabric and a thermal bond non-woven fabric (a reinforcing layer made of an average). The thickness of the filter medium 3 was 0.58 mm. The collection efficiency was 40 Pa and 65%. Next, the prepared filter medium sheet was pleated by alternately performing mountain folds and valley folds every 260 mm with a rotary folding machine to obtain a zigzag-shaped filter medium 3. The outer dimensions of the filter medium 3 were 580 mm in length (length in Z direction) x 580 mm in width (length in Y direction) x 290 mm in depth (length in X direction). The width was 125 mm and the number of pleats was 100.

Next, a string-shaped spacing member 5 having a thickness of 6 mm was formed on the filter medium 3 by a transfer method using a thermoplastic resin made of an aliphatic polyamide having a softening point of 155 ° C. The viscosity of this thermoplastic resin was 4100 mPa · s, and the glass transition point was −45 ° C. Specifically, the thermoplastic resin was heated to 230 ° C. to melt it, and applied to the groove 40a of the jig 40 at room temperature. After application, the jig 40 is allowed to stand for 10 seconds, turned upside down, and placed on the filter medium 3 having a constant width so that the extending direction of the jig 40 coincides with the width direction, and the jig 40 is placed for another 60 seconds. I left it.
When the jig 40 was removed from the space-holding material 5, the space-holding material 5 did not adhere to the jig 40. Further, even if the operation of turning the prepared filter pack 10 upside down was repeated 5 times, the interval holding material 5 did not fall off from the filter material 3. When the prepared filter pack was observed, the sagging of the interval holding material 5 was suppressed, and the D / S was 17%.
Next, the produced filter pack was fixed to a stainless steel frame 14 having an outer dimension of 610 mm in length × 610 mm in width, an inner dimension of 580 mm in length × 580 mm in width, and a depth of 150 mm. The periphery of the filter pack was sealed by joining with the frame body 14 with urethane foam to obtain an air filter 30. The manufactured air filter 30 has all the components including the spacing member 5 that are flame-retardant or non-flammable at a height of JACA (Japan Air Cleaning Association) flame-retardant class3, UL94 V-0, and UL94 HBF or higher. Had had.

(Comparison example)
As the thermoplastic resin, an aliphatic polyamide having a softening point of 185 ° C., a viscosity of 3400 mPa · s, and a glass transition point of −45 ° C. was used to prepare a filter pack in the same manner as in Examples except that an interval holding material was formed. I tried. In the comparative example, when the jig was removed from the space-holding material 5, the space-holding material 5 was peeled off from a part of the filter material 3. Further, the interval holding material 5 fell off from the filter material 3 until the operation of turning the produced filter pack upside down was repeated 5 times. In the comparative example, when the resin was transferred to the filter medium, it began to cure, and the spacing material was not sufficiently adhered to the filter medium. In the comparative example, it is considered that the resin was cured quickly because the softening point of the resin exceeded 180 ° C.

The filter pack, the air filter, the method for manufacturing the filter pack, and the method for manufacturing the air filter of the present invention have been described in detail above. Of course, the method is not limited to the above-described embodiment or embodiment, and various improvements and changes may be made without departing from the gist of the present invention.

1A, 1B, 1C, 1D, 1E Protrusion part 3 Filter material 3a Mountain part 3b Valley part 5 Spacing holding material 10 Filter pack 20 Frame body 30 Air filter

Claims (5)

A pleated filter medium that collects fine particles in gas,
A space-holding material for holding the pleated space of the filter medium is provided.
The filter medium is arranged on the first side of the direction of the airflow passing through the filter medium, and has a plurality of mountain folds and a second side opposite to the first side and the direction of the airflow. It has multiple valleys, which are arranged on the side and folded in valleys,
The spacing material extends along the direction in which the peaks are lined up on the first side, and is bridged over the peaks so as to be in contact with the respective vertices of the peaks, and is polyamide-based, polyurethane-based, or polyolefin. It is a type of resin and consists of a thermoplastic resin with a softening point of 150 to 180 ° C.
Along the direction of the air flow between the apex of the mountain portion and the end of the second side recessed to the second side of the portion of the spacing material between the two adjacent mountain portions. A filter pack characterized in that the ratio D / S of the interval D to the interval S of the two peaks is 0 to 30%. The filter medium has an embossed protrusion that projects to the first side on each of the flat surfaces that extend between the peak and the valley at an angle with respect to the direction of the air flow. Then, the protrusions of the two flat surfaces extending from the valley are formed at positions where they are in contact with each other.
The filter pack according to claim 1, wherein the spacing member is arranged at the same position as the protrusion in a direction parallel to the direction in which the crease of the mountain portion extends. The filter pack according to claim 1 or 2,
An air filter including a frame body for holding the filter pack. A step of pleating a filter medium sheet that collects fine particles in a gas to prepare a filter medium, and
A step of forming an interval holding material for holding the pleated interval of the filter medium on the filter medium is provided.
In the step of producing the filter medium, the plurality of mountain portions arranged on the first side of the direction of the airflow passing through the filter medium, and the first side and the opposite side of the direction of the airflow. A plurality of valleys, which are arranged on a second side and are valley-folded, are formed.
In the step of forming the spacing material, a thermoplastic resin which is a polyamide-based, polyurethane-based, or polyolefin-based resin and has a softening point of 150 to 180 ° C. is arranged so as to extend in one direction without contacting the filter medium. The filter pack is characterized in that the arranged thermoplastic resin is brought into contact with the filter medium along the direction in which the mountain portions are lined up on the first side so as to be in contact with each apex of the mountain portion. Manufacturing method. The step of manufacturing the filter pack according to the method for manufacturing the filter pack according to claim 4, and the process of manufacturing the filter pack.
A method for manufacturing an air filter, which comprises a step of holding the filter pack in a frame.

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