WO2020145345A1

WO2020145345A1 - Air filter

Info

Publication number: WO2020145345A1
Application number: PCT/JP2020/000446
Authority: WO
Inventors: 健太郎田中; 卓尾林; 健太郎甲斐; 正千代今西
Original assignee: 王子ホールディングス株式会社; 大阪ガスケミカル株式会社
Priority date: 2019-01-09
Filing date: 2020-01-09
Publication date: 2020-07-16
Also published as: KR20210109555A; CN111420473A; JP7393352B2; TW202037382A; JPWO2020145345A1

Abstract

Provided is an air filter which is filled with an active filler and which has improved adsorption efficiency and sustainability while suppressing an increase in pressure loss. This air filter, which is a planar air filter having a first surface and a second surface, comprises: a corrugated honeycomb structure (1) that defines a plurality of cells (30) arranged in a plane direction; and a plurality of porous fillers (50) that are filled in the plurality of cells (30), wherein the plurality of cells (30) include a plurality of minimum-diameter cells (31) and a plurality of large-diameter cells (a first large-diameter cell (32) and a second large-diameter cell (33)), the plurality of minimum-diameter cells are cells having the smallest inscribed circle diameter, the plurality of large-diameter cells are cells having a larger inscribed circle diameter than the plurality of minimum-diameter cells, the ratio of the number of the minimum-diameter cells (31) filled with the filler to the number of the minimum-diameter cells (31) is 50% or less, and the ratio of the number of the large-diameter cells filled with the filler to the number of the large-diameter cells is 25-100%.

Description

Air filter

The present invention relates to an air filter used for purposes such as deodorization.
The present application claims priority on the basis of application number 201910020245.3, filed with the China Intellectual Property Office on January 9, 2019, the content of which is incorporated herein by reference.

In air purifiers and the like, as an air filter used for the purpose of deodorization and the like, a corrugated honeycomb structure having a large number of cells is known by alternately stacking a plurality of liner members and a plurality of corrugated members. ..
The air to be treated is purified by the malodorous components and the like adsorbing to the corrugated honeycomb structure while passing through the cells.
As a material for the corrugated honeycomb structure, paper to which an adsorbent is attached or contained is usually used.
A deodorizing filter in which cells of a corrugated honeycomb structure are filled with activated carbon or the like has also been proposed for the purpose of improving adsorption efficiency and sustainability (Patent Document 1).

JP, 2003-47649, A

However, in order to fill the cell with activated carbon etc. as in Patent Document 1, a somewhat large cell is required. In that case, the air to be treated cannot sufficiently come into contact with the corrugated honeycomb structure while passing through the cells, and it becomes difficult to exhibit the immediate adsorbing performance which is an advantage of the corrugated honeycomb structure.

If activated carbon or the like is made fine, it is possible to fill the cell without making it too large. However, in that case, the cells are clogged with fine activated carbon and the like, resulting in a very high pressure loss.
Therefore, the air filter in which the cells of the corrugated honeycomb structure are filled with activated carbon or the like as in Patent Document 1 has not been put to practical use.

The present invention has been made in view of the above circumstances, and provides an air filter having enhanced adsorption efficiency and sustainability by being filled with a filler such as activated carbon while suppressing an increase in pressure loss. Is an issue.

The present invention has the following features to attain the object mentioned above.
[1] A planar air filter having a first surface and a second surface,
A corrugated honeycomb structure that defines a plurality of cells arranged in the surface direction, and a plurality of porous fillers filled in the plurality of cells,
The plurality of cells comprises a plurality of smallest diameter cells and a plurality of large diameter cells,
The plurality of smallest diameter cells are cells having the smallest diameter of the inscribed circle,
The plurality of large-diameter cells is a cell in which the diameter of the inscribed circle is larger than the diameter of the inscribed circle of the plurality of smallest-diameter cells,
The ratio of the number of the minimum diameter cells filled with the filler to the number of the minimum diameter cells is 50% or less,
The air filter, wherein the ratio of the number of the large-sized cells filled with the filler in the number of the large-sized cells is 25 to 100%.
[2] The air filter according to [1], wherein the ratio of the smallest diameter cell to the plurality of cells is 10 to 90 area %.
[3] The corrugated honeycomb structure is configured by bonding a plurality of liner members and a plurality of corrugated members to each other,
The plurality of liner members are linear when observed from a direction perpendicular to the surface direction,
The plurality of corrugated members has a corrugated shape in which peaks and valleys are repeated along the direction in which the liner member extends when observed from a direction perpendicular to the surface direction,
The air filter according to [1] or [2], wherein the plurality of corrugated members include two or more kinds of corrugated members having different heights and/or pitches of the corrugated shape.
[4] The air filter according to [3], wherein the plurality of corrugated members include a pair or more of corrugated members whose peaks are directly bonded to each other without interposing the liner member.
[5] The air filter according to any one of [1] to [4], wherein an adsorbent is held by the corrugated honeycomb structure.
[6] The air filter according to any one of [1] to [5], wherein the plurality of fillers are spherical.
[7] The air filter according to any one of [1] to [6], wherein the filler is activated carbon.
[8] The air filter according to any one of [1] to [7], wherein a breathable sheet is arranged on one or both of the first surface and the second surface.

According to the air filter of the present invention filled with a filler such as activated carbon, it is possible to enhance adsorption efficiency and sustainability while suppressing an increase in pressure loss.

It is a top view of the corrugated honeycomb structure used for the air filter which concerns on one Embodiment of this invention. It is a partially expanded view of the corrugated honeycomb structure of FIG. It is sectional drawing of the air filter which concerns on one Embodiment of this invention. It is an enlarged photograph of the air filter which concerns on an Example.

The air filter of the present invention comprises a corrugated honeycomb structure defining a plurality of cells arranged in the plane direction, and a plurality of porous fillers filled in the plurality of cells.
FIG. 1 is a view of a corrugated honeycomb structure 1 used for an air filter according to an embodiment of the present invention as seen from a direction perpendicular to a plane direction. The corrugated honeycomb structure 1 is composed of a liner member 10 and a corrugated member 20, and is a planar body in which the front side of the paper surface in FIG. 1 is a first surface 61 and the back side of the paper surface is a second surface 62.
The thickness of the corrugated honeycomb structure (the length in the depth direction of the cells of the corrugated honeycomb structure, which will be described later) may be adjusted in the range of 5 to 100 mm, and usually 5 to 50 mm.

As shown in FIG. 1, the liner member 10 looks like a straight line or a substantially straight line when observed from a direction perpendicular to the surface direction, and is a strip-shaped member having a width in the thickness direction of the paper surface of FIG.
As shown in FIG. 1, the corrugated member 20 has a corrugated shape in which a strip-shaped member is repeatedly bent, and peaks and valleys are repeated along the direction in which the liner member 10 extends when observed from a direction perpendicular to the plane direction. It is a shaped member.

In this embodiment, two kinds of corrugated members 20, a small corrugated member 21 and a large corrugated member 22, are used. The pitch and height of the large corrugated member 22 are larger than the pitch and height of the small corrugated member 21.
As shown in FIG. 2, the valley portion 21b of the small corrugated member 21 is bonded to one liner member 10, and the peak portion 21a is bonded to another liner member 10.
On the other hand, the valley portion 22b of the large corrugated member 22 is bonded to the one liner member 10, but the crest portion 22a does not involve the other one liner member 10 and the other large corrugated member 22. Is directly bonded to the mountain portion 22a.

As shown in FIGS. 1 and 2, in the corrugated honeycomb structure 1, a plurality of cells 30 defined by the liner member 10 and the corrugated member 20 are formed so as to be arranged in the plane direction.
In the present embodiment, as the cell 30, a minimum diameter cell 31 and two types of large diameter cells (first large diameter cell 32 and second large diameter cell 33) are formed.
The smallest diameter cell 31 is a space defined by the liner member 10 and the small corrugated member 21. The first large-diameter cell 32 is a space defined by the liner member 10 and the large corrugated member 22. The second large-diameter cell 33 is a space defined by the pair of large corrugated members 22 to which the mountain portions 22a are directly adhered.

In FIG. 2, a minimum diameter inscribed circle 41 is an inscribed circle of the minimum diameter cell 31, a first large diameter inscribed circle 42 is an inscribed circle of the first large diameter cell 32, and a second large diameter inscribed circle. The circle 43 is an inscribed circle of the second large diameter cell 33.
Of these inscribed circles, the smallest diameter inscribed circle 41 has the smallest diameter, and the diameters of the first large diameter inscribed circle 42 and the second large diameter inscribed circle 43 are smaller than the diameter of the smallest diameter inscribed circle 41. large. The diameter of the second large-diameter inscribed circle 43 is larger than the diameter of the first large-diameter inscribed circle 42.

The smallest-diameter cell 31 inscribed by the smallest-diameter inscribed circle 41 has a small opening area, so it is difficult for the filler to be filled and the gas can smoothly pass through. Further, since the opening area of the smallest diameter cell 31 is small, the gas passing through the smallest diameter cell 31 can sufficiently contact the liner member 10 and the small corrugated member 21, and the malodorous components and the like are adsorbed on these members. Cheap.

In addition, the first large-diameter cell 32 and the second large-diameter cell 33, which are inscribed by an inscribed circle having a diameter larger than the minimum-diameter inscribed circle 41, have a sufficient size so that the minimum-diameter cell 31 is difficult to enter. Can be filled. Therefore, it is possible to enhance the adsorption efficiency and sustainability by the filler while suppressing the increase in pressure loss.
In addition, as in the present embodiment, when there are a plurality of types of large-diameter cells (first large-diameter cell 32, second large-diameter cell 33) having different inscribed circle diameters, the effect of suppressing an increase in pressure loss can be obtained. Further, it is possible to prevent clogging at the same time when used for a long time. Further, it is easy to fill a plurality of types of fillers having different sizes. Therefore, it is easy to use a plurality of types of fillers having different adsorption characteristics.

The ratio of the total area of the smallest diameter cells 31 to the total area (100%) of the cells 30 in the corrugated honeycomb structure 1 (the proportion (area %) of the smallest diameter cells 31 in the plurality of cells 30 of the corrugated honeycomb structure 1) Is preferably 10 to 90%, more preferably 15 to 75%, and further preferably 20 to 50%.
When the ratio is equal to or higher than the preferable lower limit value, it is easy to secure air permeability and suppress an increase in pressure loss. Further, when the ratio is equal to or less than the preferable upper limit value, it is easy to fill the first large diameter cell 32 and the second large diameter cell 33 with a sufficient amount of the filler.
The total area of the first large-diameter cell 32 and the total area of the second large-diameter cell 33 may be appropriately adjusted according to the blending amount for each size of the filler to be filled.

It is preferable that the smallest diameter cells 31, the first large diameter cells 32, and the second large diameter cells 33 are distributed as evenly as possible in the direction in which the liner members 10 are arranged. This can prevent a partial increase in pressure loss.

The diameter of the smallest diameter inscribed circle 41 is preferably 0.5 to 3 mm, more preferably 1 to 2.5 mm, and further preferably 1.5 to 2.0 mm.
When the diameter of the smallest diameter inscribed circle 41 is equal to or larger than the lower limit value of the preferable range, it is difficult to prevent gas from passing through the smallest diameter cell 31. If the diameter of the smallest diameter inscribed circle 41 is equal to or less than the upper limit value of the preferable range, the gas passing through the smallest diameter cell 31 is sufficiently brought into contact with the corrugated honeycomb structure 1 so that the malodorous components and the like are transferred to the corrugated honeycomb structure 1. Can be adsorbed.

The diameters of the first large diameter inscribed circle 42 and the second large diameter inscribed circle 43 are preferably 1.1 times or more, and preferably 1.5 times or more, the diameter of the smallest diameter inscribed circle 41. More preferable.
When the ratio is equal to or more than the preferable ratio, it is easy to fill the first large diameter cell 32 and the second large diameter cell 33 with the filler while suppressing the filling of the smallest diameter cell 31 with the filler.

The diameter of the first large diameter inscribed circle 42 is preferably 1 to 6 mm, more preferably 1 to 4 mm, and further preferably 2 to 3 mm.
When the diameter of the first large-diameter inscribed circle 42 is equal to or larger than the lower limit value of the preferable range, it is easy to fill the first large-diameter cell 32 with the filler. If the diameter of the first large-diameter inscribed circle 42 is equal to or smaller than the upper limit of the preferable range, the area of the first large-diameter cell 32 does not become excessively large, and the strength of the corrugated honeycomb structure 1 can be easily ensured.

The diameter of the second large diameter inscribed circle 43 is preferably 1.1 times or more, and more preferably 1.25 times or more the diameter of the first large diameter inscribed circle 42.
When the ratio is equal to or more than the above preferable ratio, it is easy to fill the fillers of different sizes by using the first large diameter cell 32 and the second large diameter cell 33.

The pitch and height of the corrugated shape of the small corrugated member 21 can be determined so that the diameter of the smallest diameter inscribed circle 41 has the above-described preferable value.
Specifically, the pitch of the corrugated shape of the small corrugated member 21 is preferably 2 to 7 mm, more preferably 3 to 6 mm.
The corrugated height of the small corrugated member 21 is preferably 0.5 to 3 mm, more preferably 1 to 2.5 mm.
The corrugated height of the small corrugated member 21 is the distance in the height direction between the valleys 21b and the ridges 21a on one surface of the small corrugated member 21, and the height direction means the liner member 10. It is a direction orthogonal to each other.

Further, the pitch and height of the corrugated shape of the large corrugated member 22 can be determined so that the diameters of the first large diameter inscribed circle 42 and the second large diameter inscribed circle 43 are the above-mentioned preferable values.
Specifically, the corrugated pitch of the large corrugated member 22 is preferably 4 to 12 mm, and more preferably 5 to 10 mm.
The corrugated height of the large corrugated member 22 is preferably 2 to 6 mm, more preferably 2.5 to 5 mm.
The corrugated height of the large corrugated member 22 is the distance in the height direction between the valleys 22b and the ridges 22a on one surface of the large corrugated member 22, and the height direction means the liner member 10. It is a direction orthogonal to each other.

The liner member 10 and the corrugated member 20 of the corrugated honeycomb structure 1 are preferably composed of a base material and an adsorbent held by the base material.
The base material is not particularly limited as long as it is a sheet-shaped base material such as papers, non-woven fabrics and plastic films, but a fiber base material is preferable from the viewpoint of easily holding the adsorbent. Examples of the fiber substrate include a paper substrate containing cellulose fiber as a main component and a plastic substrate containing synthetic fiber as a main component. Of these, a paper base material containing cellulose fibers as a main component is preferable.
In addition, "to be a main component" means that the ratio to the whole base material is 50% by mass or more.

The paper base material is typically composed of pulp containing cellulose fibers. Examples of pulp containing cellulose fibers include wood pulp and non-wood pulp. Examples of the wood pulp include softwood pulp and hardwood pulp. Examples of the non-wood pulp include hemp pulp, kenaf pulp, bamboo pulp and the like.

The wood pulp may have been subjected to a cooking process and/or a bleaching process. In general, wood pulp is used after being subjected to various cooking and bleaching steps in order to remove components other than cellulose from the raw material wood. In the present invention, the cooking step and the bleaching step are not particularly limited, and a known method can be appropriately used.
These pulps may be used alone or in combination of two or more.

The paper substrate may further contain fibers other than cellulose fibers. Examples of other fibers include rayon fibers, polyethylene fibers, polypropylene fibers, polyester fibers and other synthetic fibers, glass fibers, ceramic fibers, mineral fibers and other inorganic fibers, and animal fibers.
The paper base material may contain internal additives such as a sizing agent, a paper strengthening agent, a coloring agent, a preservative, and a flame retardant. Known internal additives can be used.

Examples of the plastic substrate include those containing, as a main component, one or more kinds of synthetic fibers such as rayon fiber, polyethylene fiber, polypropylene fiber and polyester fiber.
The basis weight of the base material is preferably 10 to 500 g/m ² , more preferably 10 to 400 g/m ² , and even more preferably 10 to 300 g/m ² .
The fiber base material is preferably obtained by a papermaking method.

Examples of the adsorbent to be held on the base material include known adsorbents such as granular, powdery, fibrous and the like activated carbon, mordenite, ferrierite, molecular sieves and other zeolites, silica gel and alumina gel. A chemical that reacts with the component to be removed (for example, a compound that reacts with ammonia or formaldehyde) may be carried on these adsorbents. Alternatively, a chemical that reacts with the component to be removed may be directly supported on the base material.
The adsorbent to be held on the base material may be held inside the base material, adhered to the surface, or present both inside and on the surface.
The adsorbent to be held on the substrate may be added internally during paper making, or may be applied or impregnated after paper making.

The method of manufacturing the corrugated honeycomb structure 1 is not particularly limited, but a single corrugated cardboard in which the small corrugated member 21 is bonded to the liner member 10 (hereinafter referred to as "small corrugated cardboard") and a large corrugated member 22 in the liner member 10 are bonded. It is preferable that the single-sided corrugated board (hereinafter referred to as “large-sized corrugated board”) thus laminated is laminated and bonded.

Further, in the large-sized corrugated board, the mountain portions 22a of the pair of large corrugated members 22 are bonded to each other, the pair of large corrugated members 22 are bonded between the pair of liner members 10, and the mountain portions 22a of the pair of large corrugated members 22 are bonded to each other. It is preferable that the structure sandwiched in this state (hereinafter referred to as “X structure flute”. In the present embodiment, the X structure flute 70 in FIG. 2) is laminated and adhered to the X structure flute 70 and the small piece corrugated board.

When laminating and bonding the X structure flute 70 and the small piece corrugated board, the liner member 10 of the X structure flute 70 and the liner member 10 of the small piece corrugated board may be overlapped. Further, the small corrugated cardboard on the side of the small corrugated member 21 is adhered to the liner member 10 of the X structure flute 70, and the liner member 10 of the small corrugated cardboard and the liner member 10 of other small corrugated cardboard are overlapped and laminated and bonded. Good.
That is, when the corrugated honeycomb structure 1 is manufactured by laminating and adhering the small piece corrugated board and the X-structure flute, the part where the liner member 10 that constitutes one piece corrugated board is present independently and the two pieces that form a pair of piece corrugated board. And a portion of the liner member 10 existing in a state of being overlapped with each other.

FIG. 3 is a schematic sectional view of an air filter according to an embodiment of the present invention. In the air filter of FIG. 3, the cells 30 of the corrugated honeycomb structure 1 shown in FIGS. 1 and 2 are filled with a plurality of porous fillers 50, and the first surface 61 and the second surface of the corrugated honeycomb structure 1 are formed. 62, a breathable sheet 71 and a breathable sheet 72 are arranged respectively.

Since the filler 50 is porous, it has the ability to adsorb removed components such as malodors. Examples of the filler 50 include granular, powder and fibrous activated carbon, mordenite, ferrierite, zeolite such as molecular sieves, silica gel and alumina gel. Among them, activated carbon is preferable, granular activated carbon is more preferable, and spherical or substantially spherical activated carbon is particularly preferable.

The filler 50 may carry a chemical that reacts with a component to be removed such as an inorganic acid.
The filler 50 is preferably granular, more preferably substantially spherical, and particularly preferably spherical. If the cells 30 are spherical or substantially spherical, the cells 30 can be easily filled, and an appropriate gap is created between the cells 30 and the liner member 10 or the corrugated member 20 that defines the cells 30, so that ventilation can be easily ensured.

The average particle size of the filler 50 is preferably 500 to 10000 μm, more preferably 1000 to 5000 μm. The average particle diameter is measured by the mass average particle diameter method according to JIS K1474 (Activated carbon test method-Average particle diameter measurement method).

The specific surface area of the filler 50 is preferably 600 to 2200 m ² /g. The specific surface area is the BET specific surface area measured by the nitrogen gas adsorption method.
When the specific surface area of the filler 50 is equal to or more than the preferable lower limit value, it is easy to exhibit the adsorption performance of the malodorous component and the like. When the specific surface area of the filler 50 is equal to or less than the preferable upper limit value, the strength of the filler 50 is easily maintained.

The ratio (filling rate) of the number of the smallest diameter cells 31 filled with the filler 50 to the number (100%) of the smallest diameter cells 31 is preferably 50% or less, and more preferably 25% or less. It is preferably 10% or less, and more preferably 10% or less.
If the filling rate of the smallest diameter cells 31 is equal to or lower than the preferable upper limit value, it is easy to ensure air permeability.
In order to set the filling rate of the smallest diameter cell 31 to be equal to or less than the preferable upper limit value, the proportion of the filler 50 having a diameter smaller than that of the smallest diameter inscribed circle 41 to the entire filler 50 may be lowered.
The lower limit of the filling rate of the smallest diameter cells 31 may be 0%. That is, the minimum diameter cell 31 may not be filled with the filler 50.

On the other hand, the ratio of the number of large-diameter cells filled with the filler 50 to the number (100%) of the large-diameter cells (the first large-diameter cell 32 and the second large-diameter cell 33 in this embodiment) (filling ratio) ) Is preferably 25 to 100%, more preferably 50 to 100%, and further preferably 75 to 100%.
When the filling rate of the large-diameter cell is equal to or higher than the preferable lower limit value, it is easy to increase the adsorption efficiency and sustainability by the filler 50. If the filling rate of the large-diameter cell is equal to or less than the preferable upper limit value, the filling operation is easy.
In determining the filling rate, cells filled with at least one filling agent are treated as filled cells regardless of the size of the filling agent 50.

FIG. 3 schematically shows an example in which a spherical small filler 51 and a large filler 52 larger than the small filler 51 are filled as the filler 50.
The diameter of the small filler 51 is preferably larger than the minimum diameter inscribed circle 41. As a result, the small filler 51 is less likely to be filled in the smallest diameter cell 31.
Even if the diameter of the filler 50 is larger than the smallest diameter inscribed circle 41, the smallest diameter cell 31 may be filled with the filler 50 or the like that is broken due to cracking or the like.

Since the filler 50 is filled in the cells 30, each diameter is smaller than the second large diameter inscribed circle 43. Further, the diameter of the large filler 52 is preferably larger than the first large diameter inscribed circle 42. Thereby, the large filler 52 is easily filled in the second large-diameter cell 33, and the filling rate of the second large-diameter cell 33 can be improved.

The breathable sheet 71 and the breathable sheet 72 are made of a breathable material such as nonwoven fabric or mesh cloth. Examples of the material forming the non-woven fabric, the mesh cloth and the like include rayon, polyester, nylon and the like.
The breathable sheet 71 and the breathable sheet 72 are arranged by being bonded to the first surface 61 value and the second surface 62 of the corrugated honeycomb structure 1, respectively.
By positioning the breathable sheet 71 and the breathable sheet 72, it is possible to prevent the filler 50 from falling off from the air filter. Further, dust or the like can be removed from the gas passing through the air filter.

Although the corrugated honeycomb structure 1 having the X-structured flutes 70 is shown in FIGS. 1 and 2, it is not always necessary to have the X-structured flutes 70. For example, three types of single-faced corrugated boards having different sizes may be used in combination and laminated.
The large-diameter cell is not limited to two types as shown in FIGS. 1 and 2, and may be one type or three or more types.
Also, the shape of the cell 30 is not particularly limited.
Further, in FIGS. 1 and 2, the large corrugated member 22 and the small corrugated member 21 are different in both pitch and height, but a plurality of types of corrugated members 20 different in only one of pitch and height are used. Good.
Further, the corrugated member 20 may be of one type as long as the cells 30 can include cells of different sizes. For example, a plurality of X-structure flutes made by using one type of corrugated cardboard may be laminated.
The shape and size of the filler 50 are not limited to two types as shown in FIG. 3, and may be three or more types.

[Example 1]
A glass fiber mixed paper (manufactured by Oji Ftex Co., Ltd.) having a basis weight of 50 g/m ² is used as a liner base paper, and an adsorbent dispersion liquid containing activated carbon, an inorganic adsorbent, a chemical adsorbent, etc. at a rate of 200 g/L is impregnated into the liner It was a member.
A glass fiber blended paper (manufactured by Oji Ftex Co., Ltd.) paper having a basis weight of 50 g/m ² was used as a corrugated base paper and impregnated with an adsorbent dispersion liquid containing activated carbon, an inorganic adsorbent, a chemical adsorbent, etc. at a ratio of 200 g/L. Used as a corrugated substrate.
The corrugated base material was corrugated to form a corrugated member, and then a liner member and a piece of corrugated cardboard were formed. Two types of single-faced corrugated board, small-sized corrugated cardboard and large-sized corrugated board, having different heights and pitches were prepared. A small corrugated member having a pitch of 4.9 mm and a height of 2 mm was used for the small piece corrugated board, and a large corrugated member having a pitch of 5.9 mm and a height of 3 mm was used for the large piece corrugated board.

A laminated body in which two pieces of the obtained large-sized corrugated board are bonded so that the ridge lines of the large corrugated members are aligned with each other so that the liner members are on both outer sides, and the corrugated members of the small-sized corrugated board are respectively bonded to the liner members on both outer sides. Got A plurality of these laminated bodies were stacked to obtain a corrugated honeycomb structure equivalent to that shown in FIG. In addition, each piece of corrugated cardboard was laminated by aligning the ridge direction of the corrugated member. The thickness of the corrugated honeycomb structure (length in the depth direction of cells) was set to 15 mm.

A gas-permeable sheet was adhered to one surface of the obtained corrugated honeycomb structure, and a chemical-supporting spherical activated carbon ((average particle diameter 2 mm, BET specific surface area 930 m of Osaka Gas Chemical Co., Ltd. was used as a filler from the other surface. ² /g) of which 23 g was filled in. Then, a breathable sheet was also bonded to the other surface to obtain the air filter of Example 1.
A polyester mesh (opening 1 mm) was used as the breathable sheet.

[Comparative Example 1]
An air filter was obtained in the same manner as in Example 1 except that only the large-sized corrugated board used in Example 1 had a structure in which a plurality of liner members and corrugated members were adhered to each other and laminated. A plurality of large-sized corrugated cardboards were laminated by aligning the ridge direction of the corrugated member.

[Pressure loss evaluation]
After putting the obtained air filter in a resin case with an opening of 100 mm × 100 mm, set it in a wind tunnel device, and each line of 0.5 m/s, 1.0 m/s, 1.5 m/s, 2.0 m/s The pressure loss at high speed was measured.
The results are shown in Table 1.

As shown in Table 1, it can be seen that the air filter of Example 1 is superior to Comparative Example 1 in terms of pressure loss.
FIG. 4 is an enlarged photograph taken from the other surface of the air filter of Example 1 before adhering the breathable sheet to the other surface. As shown in FIG. 4, it was confirmed that the smallest diameter cell was hardly filled with the filler and the filling rate did not exceed 50%. Further, it was confirmed that the filler could be filled in most of the large-diameter cells, and the filling rate was at least 25% or more. Particularly, the filling rate of the large-diameter cell (corresponding to the second large-diameter cell 33 in FIG. 1) having a large diameter of the inscribed circle was high.
That is, in Example 1, it was possible to confirm whether or not the filler such as activated carbon could be filled while suppressing the increase of the pressure loss by ensuring the cells which are not filled with the filler and through which the gas easily passes.

[Comparative Example 2]
An air filter was obtained in the same manner as in Example 1 except that spherical activated carbon was not filled.

[Formaldehyde removal performance evaluation]
Adopted an evaluation test based on the Chinese GB standard (GB/T 18801-2015) and conducted a simple test with a test chamber size of 1 m ³ to show the clean air supply rate (CADR) and clean air after formaldehyde loading of the air filter. The formaldehyde removal performance was evaluated by measuring the supply rate maintenance rate (CADR maintenance rate).

(Measurement of initial CADR)
The air purifying fan equipped with the air filters obtained in Example 1 and Comparative Example 2 was set, and the air purifying fan was sealed in the test chamber so that the air concentration of formaldehyde was 1 ppm, and the air purifying fan was the same as the target air purifier. Operate at a linear velocity (LV) of 1.0 m/s, measure the formaldehyde air concentration for 60 minutes at 5 minute intervals using a formaldehyde meter htv. From the relationship between elapsed time and formaldehyde air concentration, the initial clean The air supply rate (initial CADR) was measured.
The results are shown in Table 2.

(Measurement of CADR after loading with formaldehyde)
Next, an air purifying fan equipped with the air filters obtained in Example 1 and Comparative Example 2 was set, and the filter paper on the volatilization fan was impregnated with the formaldehyde solution so that the mass of formaldehyde was 20 mg. And the volatilization fan was operated and left for 12 hours.

Further, set an air purifying fan equipped with an air filter that has been subjected to the above treatment, and seal it in a test room (1 m ³ ) so that the concentration of formaldehyde in the air will be 1 ppm, and use the air purifying fan as the target air purifier. Operate at the same linear velocity (LV) of 1.0 m/s, measure the formaldehyde air concentration for 60 minutes at 5 minute intervals using a formaldehyde meter htv. From the relationship between elapsed time and formaldehyde air concentration, formaldehyde The clean air supply rate (CADR) after loading 20 mg/sheet was measured.

From the relationship between the initial clean air supply rate (initial CADR) and the above-mentioned formaldehyde 20 mg/sheet clean air supply rate (CADR), the clean air supply rate maintenance rate after 20 mg loading (CADR maintenance rate) was calculated.

As shown in Table 2, the air filter of Example 1 exhibited high adsorption performance not only at the initial stage but also after adsorption of 20 mg.

The air filter filled with the filler such as activated carbon according to the present invention can improve adsorption efficiency and sustainability while suppressing an increase in pressure loss.
The air filter of the present invention can be used in an air purifier, an air conditioner, a dehumidifier, etc. for the purpose of removing offensive odor components, harmful components and the like.

1 Corrugated honeycomb structure 10 Liner member 20 Corrugated member 21 Small corrugated member 22 Large corrugated member 30 Cell 31 Smallest diameter cell 32 First large diameter cell 33 Second large diameter cell 41 Smallest diameter inscribed circle 42 First large diameter inscribed Circle 43 Second large-diameter inscribed circle 50 Filler 51 Small filler 52 Large filler 61 First surface 62 Second surface 71 Breathable sheet 72 Breathable sheet

Claims

A planar air filter having a first surface and a second surface,
A corrugated honeycomb structure that defines a plurality of cells arranged in the surface direction, and a plurality of porous fillers filled in the plurality of cells,
The plurality of cells comprises a plurality of smallest diameter cells and a plurality of large diameter cells,
The plurality of smallest diameter cells are cells having the smallest diameter of the inscribed circle,
The plurality of large-diameter cells is a cell in which the diameter of the inscribed circle is larger than the diameter of the inscribed circle of the plurality of smallest-diameter cells,
The ratio of the number of the minimum diameter cells filled with the filler to the number of the minimum diameter cells is 50% or less,
The air filter, wherein the ratio of the number of the large-sized cells filled with the filler in the number of the large-sized cells is 25 to 100%.
The air filter according to claim 1, wherein the ratio of the smallest diameter cell to the plurality of cells is 10 to 90 area %.
The corrugated honeycomb structure is configured by bonding a plurality of liner members and a plurality of corrugated members to each other,
The plurality of liner members are linear when observed from a direction perpendicular to the surface direction,
The plurality of corrugated members has a corrugated shape in which peaks and valleys are repeated along the direction in which the liner member extends when observed from a direction perpendicular to the surface direction,
The air filter according to claim 1 or 2, wherein the plurality of corrugated members include two or more types of corrugated members having different heights and/or pitches of the corrugated shape.
The air filter according to claim 3, wherein the plurality of corrugated members include a pair of corrugated members whose peaks are directly bonded to each other without the liner member interposed therebetween.
The air filter according to any one of claims 1 to 4, wherein an adsorbent is held by the corrugated honeycomb structure.
The air filter according to any one of claims 1 to 5, wherein the plurality of fillers are spherical.
The air filter according to any one of claims 1 to 6, wherein the filler is activated carbon.
The air filter according to any one of claims 1 to 7, wherein a breathable sheet is arranged on one or both of the first surface and the second surface.