JP6115413B2 - Filter element - Google Patents

Description

The present invention relates to an air filter equipment such as deodorizing / dehumidifying / humidifying devices and heat exchangers, a solvent recovery device, an ozone removing device, and a gas filter element used for a humidity control material.

Conventional filter elements used in air conditioning equipment that deodorizes, dehumidifies, and humidifies indoor air include paper containing adsorbents and deodorizers, processed paper containing hygroscopic agents, or porous properties. A sheet-like material such as a resin film is used.

These sheet-like materials are used after being formed into a flat plate shape or a pleat shape, or are formed into various shapes such as a honeycomb shape as described below.

For example, a sheet-like material is first formed into a corrugated shape (flute) by a corrugator, and then fixed to and integrated with a flat liner made of the same or different material as this sheet with an adhesive. . After that, they are laminated and cut into a single plate shape or a cylindrical shape to form a honeycomb-shaped filter element (hereinafter also referred to as a honeycomb element).

In such a honeycomb-shaped element, indoor air with moisture flows in the cell surrounded by the flute and liner in the direction along the corrugated ridge, and moisture in the air is adsorbed inside the element. After being removed, it is circulated into the room as dry air.

The honeycomb filter element is required to make the cells in the laminated body as small as possible and increase the cell density without increasing the pressure loss. This is to increase efficiency such as deodorization, dehumidification, and humidification and heat exchange efficiency by increasing contact with the processing fluid per unit volume. For that purpose, it is desirable that the sheet thickness is thin.

In order to satisfy the performance as an air conditioner such as deodorizing and dehumidifying, it is necessary to have the ability to adsorb or decompose malodor causing substances and water molecules.

A conventional paper filter element uses a polymer flocculant to agglomerate an aqueous dispersion slurry in which a functional inorganic material such as activated carbon powder or zeolite is mixed with a fiber material, and the resulting floc is dewatered on a paper screen. It is manufactured by pressing and drying. Therefore, when the fibers are thick and long or the flocs are large, the deposition becomes uneven and the density becomes remarkable.

In the case of a filter element made of paper, the more thinned it is, the higher the air permeability becomes. On the other hand, dust such as cigarette smoke that should be discharged to the outside passes through the filter and passes through the air. There is a problem that it becomes impossible to purify. On the contrary, if the filter is made thick, it becomes difficult to make the cell small, and the liner density and the cell density cannot be sufficiently increased. Therefore, there is a problem that a desired deodorizing / dehumidifying efficiency cannot be obtained.

On the other hand, perforated films represented by polytetrafluoroethylene (PTFE) and polyethylene (PE) are often produced by a stretching method, and small pores are easily obtained. Excellent in terms. However, when a large amount of the functional inorganic material is blended, the film strength is lowered, so that the functional inorganic material cannot be blended at a high rate. As a result, there is a drawback that the ability to adsorb and remove contaminants and moisture in the air is insufficient, and the air cannot be sufficiently purified.

As described above, the filter element made of conventional paper is easy to mix functional inorganic materials at a high rate and can adsorb and remove contaminants, etc. Since the cell density cannot be increased, there is a limit to improving the efficiency of deodorization and dehumidification.
On the other hand, a film made of a perforated film is small in pores and substantially non-breathable, and can be thinned. Therefore, it is excellent in improving the contact efficiency of the processing gas by increasing the cell density. Yes. However, those made of perforated film cannot contain functional inorganic materials at a high rate, so that the adsorption and decomposition of contaminants, moisture absorption, etc. will be insufficient, especially in the case of deodorization, dehumidifiers, etc. It has the disadvantage of not being fully achieved.
Thus, the present condition is that the filter element with the high contact efficiency of process gas and the processing capacity per unit area is not obtained.

Also. In order to solve the above problems, Patent Document 1 proposes a filter element comprising a porous film or a porous layer having a continuous pore having a specific average pore diameter by adjusting the solid content ratio of the functional inorganic material. ing.
Further, in an air conditioner used in a closed space where moisture is constantly brought in due to a person's exhalation or the like like a car cabin, it is necessary to perform dehumidification for a long time. The method of performing dehumidification with an electric air conditioner can perform dehumidification continuously if electric power is supplied, but has a problem that the travel distance is shortened when mounted on an electric vehicle or the like.

Japanese Patent Laid-Open No. 2003-135577

Air conditioning equipment used in automobile cabins, etc., to dehumidify indoors by providing a dehumidifying function to the filter element for removing dust, odor-causing substances, and other pollutants from the air. I can do it. In such a case, it is necessary to absorb the moisture to some extent and saturate to reduce the dehumidifying ability, so that the filter element is allowed to release moisture into the outside air to quickly restore the moisture absorption performance of the filter element. However, a filter element having a functional inorganic material used for the above-mentioned purpose cannot sufficiently release moisture quickly and is not always satisfactory.

The present invention is suitably used for various air conditioners such as deodorizers, dehumidifiers and humidifiers, humidity control materials, etc., and not only has excellent deodorization and dehumidification efficiency, but also has excellent moisture release efficiency and quickly recovers moisture absorption performance. It is an object to provide a filter element that can be made to operate.

The filter element of the present invention is a filter element for gas, which is composed of a superabsorbent fiber containing a superabsorbent polymer, a crimped synthetic fiber, and a dry nonwoven fabric in which the fibers are bonded by a heat-fusible fiber. It is characterized by becoming.

The weighted average fiber length of the fibers constituting the dry nonwoven fabric is preferably in the range of 0.5 to 20 mm.
Moreover, it is preferable to make the said dry-type nonwoven fabric into the nonwoven fabric laminated body by which the different nonwoven fabric was laminated | stacked through the hot-melt adhesive on the at least one surface.

The above filter element of the present invention is suitable for forming from a filter having a pleated structure.
The above filter element of the present invention is suitable for forming from a filter having a honeycomb structure.
The filter element of the present invention is suitable for forming from a filter in which a pleated structure and a honeycomb structure are laminated.

According to the present invention, it is suitably used for various air conditioners such as deodorizers, dehumidifiers and humidifiers, humidity control materials, etc., and not only has excellent deodorization and dehumidification efficiency, but also has excellent moisture release efficiency and quick moisture absorption performance It is possible to provide a filter element that can be recovered.

It is a schematic diagram of the form of the filter element formed from the filter which has a structure with a pleat. It is a schematic diagram of the form of the filter element formed from the filter which has a honeycomb structure. It is a schematic diagram of the form of a filter element formed from a filter in which a pleated structure and a honeycomb structure are laminated.

The filter element of the present invention is a filter element that removes dust, odor-causing substances, and other various pollutants in a gas, and includes a highly water-absorbing fiber and a heat-fusible fiber made of a highly water-absorbing polymer. It is characterized by comprising.

(Superabsorbent fiber)
The superabsorbent fiber used in the present invention is not necessarily limited, but a starch graft system, a polyacrylic acid system, a superabsorbent polymer obtained by crosslinking a polymer such as a polyvinyl alcohol system, Examples thereof include superabsorbent fibers spun from superabsorbent polymers such as thermoplastic superabsorbent polymers containing polyalkylene oxide units. A superabsorbent polymer can absorb and retain water from several hundred times to about 1,000 times its own weight. In particular, acrylic acid polymers have a large number of carboxyl groups, so they are very hydrophilic, and when cross-linked into a network structure to form a sodium salt, it becomes a gel with high water absorption and exhibits excellent properties. It has been.

The superabsorbent fiber contained in the dry nonwoven fabric used in the present invention contains a superabsorbent polymer, and is a fiber having water-absorbing swellability that has both a function as a fiber and a superabsorbent polymer.
When a dry nonwoven fabric containing a superabsorbent polymer is brought into contact with air containing moisture, the moisture in the air is absorbed and the superabsorbent polymer swells to dehumidify the moisture in the air. When the dry nonwoven fabric swollen by absorbing moisture in the air is brought into contact with low-humidity air, the moisture is gradually released to return to a steady amount of moisture and can absorb moisture again.
Conventionally, inorganic hygroscopic materials such as silica gel have been studied as dehumidifying filters. Paper and non-woven fabrics with silica gel added absorb moisture in the air when exposed to moisture-containing air, and gradually release moisture when contacted with low-humidity air. I can do it.
However, the present inventors have found that the dry-type nonwoven fabric containing the superabsorbent polymer is extremely superior in moisture release compared to the dry-type nonwoven fabric containing silica gel. The reason for this is not necessarily clear, but it is assumed that the moisture absorption / release mechanism of the water-absorbing polymer is different from the adsorption / desorption of the inorganic pigment.
Since the filter element of the present invention employs a superabsorbent fiber formed from a superabsorbent polymer, when it comes into contact with air containing moisture, the superabsorbent polymer swells by absorbing moisture in the air. However, pressure loss when air passes through the nonwoven fabric tends to increase.
However, compared to the case where the superabsorbent polymer is in the form of particles and dispersed in the non-woven fabric, the superabsorbent polymer swells when the superabsorbent polymer forms the non-woven fabric while maintaining the fiber shape. However, it is considered that the voids between the fibers are easily maintained.

(Crimped synthetic fiber)
The dry nonwoven fabric forming the filter element of the present invention further contains crimped synthetic fibers. A bulky nonwoven fabric can be formed by crimping the fibers forming the nonwoven fabric. Bulky nonwoven fabrics are preferred because the spacing between the fibers constituting the nonwoven fabric is large, and even if the highly water-absorbing fibers absorb moisture and swell, it is difficult to prevent the passage of air and increase in pressure loss of the filter can be prevented. In addition, latent crimped synthetic fibers in which crimps are manifested by heat treatment can also be used. Such a latent crimp synthetic fiber is, for example, a latent crimp synthetic fiber (PET / PET composite fiber) having a side-by-side structure or an eccentric core-sheath structure obtained by compounding resins having different shrinkage ratios when heated by heat treatment. PE / PE composite fiber, PP / PP composite fiber, PE / PET composite fiber, PP / PET composite fiber, PE / PP composite fiber) and the like. As the dry nonwoven fabric used in the present invention, a dry nonwoven fabric containing superabsorbent fibers and crimped synthetic fibers and bonded with heat-bonding fibers is used. The crimped synthetic fiber may be a heat-fusible fiber or a synthetic fiber added in addition to the heat-fusible fiber. When using a heat-fusible synthetic fiber that is not crimped as a heat-fusible fiber, by containing the crimped synthetic fiber as a synthetic fiber component other than the superabsorbent fiber and the heat-fusible fiber, A bulky nonwoven fabric can be formed.
Moreover, when these crimped fibers are thick crimped fibers such as fibers having a high fineness or hollow fibers, a repellent nonwoven fabric can be obtained. Since such a repellent nonwoven fabric has resistance to deformation, it is possible to prevent the nonwoven fabric from being deformed due to moisture absorption / swelling of the superabsorbent fiber and lowering the voids.

(Heat-bonding fiber)
The superabsorbent fiber is supported on the dry nonwoven fabric forming the filter by the heat-fusible fiber used together.
This heat-fusible fiber is at least partially melted by the heat treatment in the processing step into a nonwoven fabric and acts as a binder. Polyethylene terephthalate (PET), polyethylene (PE), ethylene vinyl acetate copolymer (EVA) ) And one or more resins selected from the group consisting of polypropylene (PP) are preferably used.
Moreover, as the heat-fusible fiber, a heat-fusible composite synthetic fiber having a core-sheath structure obtained by combining two kinds of resins having different melting points and melting only the surface of the fiber is preferable.
The heat-sealable composite synthetic fiber having a core-sheath structure has a structure in which a sheath made of a resin having a low melting point is formed on the outer periphery of a core made of a resin having a high melting point. Two types of combined resin (PET / PET composite fiber, PE / PE composite fiber, PP / PP composite fiber, EVA / PP composite fiber, PE / PET composite fiber, PP / PET composite fiber, PE / PP composite fiber ).
Among these, PE / PET composite fiber, PET / PET composite fiber in which a sheath made of low-polymerization PET having a lower melting point than PET is formed on the outer periphery of a core made of high-polymerization PET, etc. Is preferred. As the heat-fusible fiber constituting the dry nonwoven fabric used in the present invention, it is preferable to use a heat-fusible fiber that is crimped (crimped, curled, spiraled).

(Other fiber components)
The dry non-woven fabric forming the filter element of the present invention includes, in addition to superabsorbent fibers, crimped synthetic fibers, and heat-fusible fibers that bind these fibers, other fibers within a range that does not impair the effects of the present invention. Ingredients can also be included.
Such other fiber components include PET, polycarbonate, nylon, polyphenylene sulfide and other non-heat-synthetic synthetic fibers, glass fibers, rock wool, carbon fibers and other inorganic fibers, rayon, plant pulp and other cellulose fibers. And so on.
Other fiber components that can be used in combination with the non-woven fabric layer containing superabsorbent fibers may be hydrophilic fibers or hydrophobic fibers. A general hydrophilic fiber is different from a superabsorbent fiber in the mechanism of moisture absorption and desorption, and does not exhibit a quick moisture absorption and desorption behavior like a superabsorbent fiber. When other hydrophilic fibers are used in combination with the non-woven fabric layer containing superabsorbent fibers, the moisture absorbed by the non-woven fabric will be retained in the hydrophilic fibers together with the superabsorbent fibers. In the case of coexisting with water, it is necessary to be careful because there is a possibility that the rapid water absorption / moisture release behavior by the superabsorbent fiber may be hindered. Further, the hydrophilic fibers may absorb moisture and soften, and the shape of the nonwoven fabric may be easily broken.

(Other materials that can be used in combination)
Various functional materials can be used in combination with the filter element of the present invention as required. Examples of such functional materials include activated carbon, zeolite, crystalline aluminophosphate type molecular sieve, silica gel, diatomaceous earth, palygoskite, sepiolite, and other porous inorganic particles having fine pores, montmorillonite, bentonite, smectite, vermiculite. Such as clay compounds such as kanemite, particles having catalytic activity such as titanium oxide and manganese oxide, calcium silicates such as zonotlite group, and inorganic powders such as silica whose surface is hydrophobized, etc. Can be mentioned.
Further, the superabsorbent polymer particles made of the same material as the superabsorbent fiber can be used in combination. Various functional material particles such as inorganic powder and highly water-absorbing polymer particles are also carried on the dry nonwoven fabric forming the filter by the heat-fusible fibers used in combination.

In the filter element of the present invention, other additives can be used as necessary.
Examples include graphite, aluminum hydroxide, magnesium hydroxide, potassium titanate, calcium carbonate, talc, silica, alumina, metal oxide, short fiber mineral fiber, ceramic fiber, glass fiber, carbon fiber, activated carbon Inorganic fibers such as fibers, silicone-based, fluorocarbon-based, long-chain fatty acid salt-based, long-chain amine salt-based water and / or oil repellents, surfactants, metal salts, silver-based antibacterial agents, fungicides, etc. Etc.

The dry nonwoven fabric production method is not particularly limited, and is a method of forming a web simultaneously with spinning, such as a spunbond method or a meltblown method, or a car that forms a web while winding cotton-like fibers using a card machine. Various known web forming methods such as a laying method and an airlaid method in which fibers loosened in an air current are deposited on a wire mesh to form a web can be employed.
The dry nonwoven fabric forming the filter of the present invention is treated at a temperature equal to or higher than the melting point of the heat-sealing fiber contained therein, and the fibers are bonded to each other by the heat-sealing fiber (thermal bonding method) and fixed in a sheet form.

Among the web forming methods described above, the web formed by the airlaid method has the properties that the fibers are oriented in the thickness direction of the web, the uniformity is high, the bulk is high, and the air permeability is excellent. Since a small filter can be obtained, it is particularly preferably used.
The proportion of superabsorbent fibers contained in the dry nonwoven fabric of the present invention is preferably adjusted to 5 to 95% by mass of the entire dry nonwoven fabric, more preferably 10 to 90, although it depends on the design of the filter element. It is 20 mass%, More preferably, it is 20-80 mass%, More preferably, it is 30-70 mass%.
That is, if it is less than 5% by mass, it is difficult to obtain a sufficient dehumidifying performance, and if it exceeds 95% by mass, the content of the heat-fusible fiber is reduced as a result, making it difficult to form a sheet.
The airlaid method can form a highly uniform web with relatively short fibers.
The superabsorbent fibers and heat-sealing fibers used in the present invention preferably have a weighted average fiber length in the range of 0.5 to 20 mm, more preferably 2 to 2, from the viewpoint of processability to a nonwoven fabric by the airlaid method. A range of 10 mm is used.
The fineness of these fibers is preferably in the range of about 0.5 to 50 dtex, more preferably in the range of 1 to 20 dtex.

As a filter formed from the nonwoven fabric sheet containing the superabsorbent fiber of the present invention, the effective area as a filter can be increased by making the nonwoven fabric sheet a pleated structure. This is a preferable embodiment of the filter element because the effect of the filter can be improved.
In addition, the use of the filter as a honeycomb element is a preferable embodiment because the contact with the processing fluid per unit volume can be increased without increasing the pressure loss.
That is, the humid air flows in the cell surrounded by the flute and the liner in the direction along the corrugated ridge, and after the moisture in the air is adsorbed and removed in the element, the dry air It is circulated into the room.
Such a honeycomb element can be manufactured, for example, by the following method.
First, a sheet-like non-woven fabric is first formed into a corrugated (flute) shape by a corrugator, and then fixed and integrated with a flat liner made of the same or different material as this sheet with an adhesive. . Thereafter, it can be manufactured by a method of laminating and cutting into a single plate shape or a cylindrical shape to form a honeycomb-shaped filter element.
Also, the filter element of the structure with pleats and the honeycomb structure can be laminated to obtain the thickness of the entire filter element.
In this case, the pleated structure and the honeycomb structure may be bonded to each other depending on the design of the filter element, or the respective structures may be simply laminated. Alternatively, the pleated structure may be laminated on the gas inlet side and the honeycomb structure gas outlet side, or the honeycomb structure may be disposed on the gas inlet side and the pleated structure may be disposed on the gas outlet side. And can be laminated. The laminated structure of each structure is preferably selected according to the characteristics of various air conditioners such as deodorizers, dehumidifiers and humidifiers in which filter elements are incorporated, and humidity control materials.

The nonwoven fabric containing superabsorbent fibers may be inferior in handleability because the superabsorbent fibers swell as the moisture absorption proceeds and the surface becomes null null. Therefore, the handleability can be improved as a nonwoven fabric laminate in which a surface layer made of a different nonwoven fabric is provided on at least one surface of a nonwoven fabric layer containing superabsorbent fibers.
The non-woven fabric used as the surface layer of the present invention is a non-hydrophilic synthetic fiber such as PE, PP, or PET, or a hydrophilic fiber such as a cellulosic fiber such as rayon or vegetable pulp fiber. The nonwoven fabric which consists of may be selected suitably according to the objective. Further, a spunbond nonwoven fabric or a spunlace nonwoven fabric made of a synthetic fiber, a needle punched nonwoven fabric, an airlaid nonwoven fabric or the like can be appropriately selected.
In the nonwoven fabric laminate having a surface layer in the present invention, it is preferable that the nonwoven fabric of the surface layer is bonded to the surface of the dry nonwoven fabric layer containing superabsorbent fibers via a heat-fusible adhesive. This is because the nonwoven fabric of the surface layer does not necessarily contain a heat-fusible fiber or a heat-fusible adhesive, and has excellent workability without sticking to a hot roll during honeycomb processing or pleating. It is because it can be set as a nonwoven fabric laminated body.
The thickness of the dry nonwoven fabric used in the filter element of the present invention is not particularly limited, but it is processed into various shapes such as pleats and corrugates, and adsorbs contaminants and moisture by increasing the cell density. From the viewpoint of improving the rate, even when a surface layer is provided, it is preferably 4 mm or less, more preferably 2 mm or less.
When the moisture in the air is removed using the filter element of the present invention, the moisture removing ability tends to be improved as the amount of water-absorbing fibers used in the filter is increased.
On the other hand, increasing the basis weight of the nonwoven fabric in order to increase the amount of superabsorbent fibers used in the filter limits the decrease in processability, the increase in cell density, and increases the pressure loss of the filter.
The basis weight of the dry nonwoven fabric used for the filter element is not particularly limited, but is adjusted in the range of ^{20 to} 1000 g / m ² , preferably 50 to 500 g / m ² , more preferably 80 to 300 g / m ² . It is a range.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples. It should be noted that “part” and “%” used in the text without any special meaning mean “part by mass” and “% by mass”, respectively.

[Production of non-woven fabric A]
A pulp non-woven fabric (trade name: Kinocross KS40, manufactured by Oji Kinocross Co., Ltd., basis weight 40 g / m ² ) produced by the airlaid method was fed out as a surface layer on a mesh endless belt that was mounted on a conveyor and traveled. Next, 8 g / m 2 of PE powder serving as an adhesive is sprayed on the surface layer, and then a sodium polyacrylate-based superabsorbent fiber (trade name: Bel Oasis) is used using an airlaid web forming machine. 67 parts by mass of fineness 10 dtex, fiber length 51 mm, manufactured by Teijin Ltd.) and heat-fusible fiber (trade name: ETC325, fineness 2.2 dtex, fiber length 5 mm, PE / PET crimped composite fiber manufactured by ES Fiber Visions) 17 The mass parts were mixed in air using a defibrator.
The mixed fibers were lowered to the mesh endless belt side along with the intake air flow and dropped and deposited on the surface layer to form an airlaid web on the surface layer. Then, after spraying 8 g / m ² of the same adhesive as that used earlier on the air laid web, the same pulp nonwoven fabric as used previously was laminated as the surface layer, and the pulp laid on both sides of the air laid web A laminated web provided with a surface layer made of nonwoven fabric was obtained.
This laminated web was heat-treated by passing through a through air dryer provided with a rotating drum having a breathable peripheral surface, containing superabsorbent fibers at a rate of 400 g / m ² , basis weight 590 g / m ² , thickness A 2.9 mm dry nonwoven fabric was obtained.

[Example 1]
The nonwoven fabric A cut to 100 mm × 3000 mm was alternately bent to 10 mm, pleated, fixed to a 100 mm × 100 mm frame, and a filter element made of a pleated structure having a thickness of 10 mm and 100 mm × 100 mm was obtained.

[Example 2]
The nonwoven fabric A was corrugated with a corrugator having a pitch of 10 mm and a height of 5 mm, and was bonded and integrated with an epoxy adhesive to a liner having the same composition, and this was laminated so that the height was 100 mm. Furthermore, it cut | judged in thickness 10mm, and obtained the filter element which consists of a honeycomb structure of height 100mm, width 100mm, and thickness 10mm.

[Example 3]
The nonwoven fabric A cut to 100 mm × 3000 mm was alternately bent to 5 mm and pleated, and fixed to a 100 mm × 100 mm frame to obtain a pleated structure a1 having a thickness of 5 mm and 100 mm × 100 mm. Next, the non-woven fabric A was corrugated with a corrugator having a pitch of 10 mm and a height of 5 mm, and bonded and integrated with a liner having the same composition with an epoxy adhesive, and this was laminated so as to have a height of 100 mm. Furthermore, it cut | judged to thickness 5mm and obtained the honeycomb structure a2 of height 100mm, width 100mm, and thickness 5mm.
A honeycomb structure a2 was laminated and bonded onto the obtained pleated structure a1 using an epoxy adhesive to obtain a filter element in which the pleated structure and the honeycomb structure were laminated.

[Production of non-woven fabric B]
Using an airlaid web forming machine, 60 parts by mass of silica gel (trade name: Artsorb, manufactured by Fuji Silysia Chemical) and 27 parts by mass of heat-fusible fiber (trade name: ETC325, manufactured by ES Fiber Visions) Using the same method as in Example 1 except that the air-laid web was used and mixed in the air, a laminated web having a surface layer made of a pulp nonwoven fabric on both surfaces of the airlaid web was obtained.
This laminated web was heat-treated by passing through a through air dryer provided with a rotating drum having a gas permeable peripheral surface, containing silica gel at a ratio of 400 g / m ² , basis weight 665 g / m ² , thickness 1. A 5 mm dry nonwoven fabric was obtained.

[Comparative Example 1]
The nonwoven fabric B cut to 100 mm × 3000 mm was alternately bent to 10 mm and pleated, fixed to a 100 mm × 100 mm frame, and a filter element made of a pleated structure having a thickness of 10 mm and 100 mm × 100 mm was obtained.

[Comparative Example 2]
The nonwoven fabric B was corrugated with a corrugator with a pitch of 10 mm and a height of 5 mm, and was bonded and integrated with an epoxy adhesive to a liner having the same composition, and this was laminated so as to have a height of 100 mm. Furthermore, it cut | judged in thickness 10mm, and obtained the filter element which consists of a honeycomb structure of height 100mm, width 100mm, and thickness 10mm.

[Comparative Example 3]
The nonwoven fabric B cut to 100 mm × 3000 mm was alternately bent to 5 mm and pleated, and fixed to a 100 mm × 100 mm frame to obtain a pleated structure b1 having a thickness of 5 mm and 100 mm × 100 mm. Next, the non-woven fabric B was corrugated with a corrugator having a pitch of 10 mm and a height of 5 mm, and bonded and integrated with a liner having the same composition with an epoxy adhesive, and this was laminated so as to have a height of 100 mm. Furthermore, it cut | judged to thickness 5mm and obtained the honeycomb structure b2 of height 100mm, width 100mm, and thickness 5mm.
A honeycomb structure b2 was laminated and bonded onto the obtained pleated structure b1 using an epoxy adhesive to obtain a filter element in which the pleated structure and the honeycomb structure were laminated.

[Hygroscopic evaluation]
Sample preparation (1) Sample dimensions: Nonwoven fabric equivalent to 100 mm x 100 mm.
(2) Cutting a portion corresponding to the nonwoven fabric sample having a predetermined area from the filter element.
(3) The cut nonwoven fabric sample is dried to a constant weight at 105 ° C., and then cooled to 25 ° C. by absolute drying.
Moisture absorption test (1) Test environment: 25 ° C, 90% RH
(2) Place the nonwoven fabric sample in the test environment and measure the change in the sample weight over time.
・ Evaluation (1) Evaluation is based on the amount of moisture absorbed up to 120 minutes after the start of moisture absorption.
○ 200 g / m ² or more Δ 100 g / m ² or more × less than 50 g / m ²

[Moisture release evaluation]
Sample preparation (1) Sample dimensions: Nonwoven fabric equivalent to 100 mm x 100 mm.
(2) Cutting a portion corresponding to the nonwoven fabric sample having a predetermined area from the filter element.
(3) Moisture to equilibrium in an environment of 25 ° C. and 90% RH, and measure the mass.
-Moisture release test (1) Test environment: 15 ° C, 35% RH
(2) Place the nonwoven fabric sample in the test environment and measure the change in the sample weight over time.
-Evaluation (1) Evaluate by the amount of moisture release up to 120 minutes after the start of moisture release.
○ 200 g / m ² or more Δ 100 g / m ² or more × less than 50 g / m ²

The filter element samples of Example 1 and Comparative Example 1 thus obtained were evaluated for hygroscopicity and moisture release. The results are shown in the table.

From the above evaluation, the filter element of the present invention not only exhibits excellent hygroscopicity but also has excellent moisture desorption properties, and not only has excellent dehumidification efficiency, but also has excellent moisture desorption efficiency and quick moisture absorption performance. It is possible to provide a filter element that can be recovered.

Claims (4)

A filter element for gas, comprising a dry nonwoven fabric layer, and a surface layer provided on at least one surface of the dry nonwoven fabric layer,
The dry nonwoven fabric layer is any of the following (i) and (ii):
The surface layer, Ri nonwoven layer der containing no superabsorbent fibers containing superabsorbent polymer,
The surface layer is bonded to the dry nonwoven fabric layer via a heat-fusible adhesive,
The filter element , wherein the surface layer does not contain a heat-fusible fiber and a heat-fusible adhesive .
(I) A dry nonwoven fabric layer comprising superabsorbent fibers containing a superabsorbent polymer and heat-fusible crimped synthetic fibers, the fibers being bonded by the heat-fusible crimped synthetic fibers.
(Ii) A superabsorbent fiber containing a superabsorbent polymer, a crimped synthetic fiber not having heat-fusibility, and a heat-fusible fiber, wherein the fibers are bonded by the heat-fusible fiber. Dry nonwoven layer. A filter comprising a pleated structure formed of the filter element according to claim 1 . A filter comprising a honeycomb structure composed of the filter element according to claim 1 . A filter comprising a pleated structure formed of the filter element according to claim 1 and a honeycomb structure.

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