JP2000024426A - Adsorption sheet, its production and air purifying filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorption sheet superior in air permeability or the like, and an air purifying filter superior in dust removing performance by providing a granular activated carbon-containing sheet containing granular activated carbon with the average particle size specified, support fibers fixed in contact with it and adhesive fibers for mainly contributing to shape holding. SOLUTION: The granular activated carbon-containing sheet used to the adsorption sheet is formed from granular activated carbon 1 having 60-600 μm average particle size, the support fibers fixed in contact with it and the adhesive fibers for mainly contributing to the shape holding. The support fibers and the adhesive fibers consist of a coexiting fiber component 2 at this time. The content of the granular activated carbon is higher as it goes to the lower side, and also a surface layer L1 less in the content of the granular activated carbon 1 compared to the back side layer L2 is formed on the upper side surface. The granular activated carbon-containing sheet incorporates 30-80 wt.% granular activated carbon and also the outer surface area of the support fiber is preferably set at not more than 1 m2/g and the fiber length of the support fibers at 3-20 mm and the specific gravity of the support fibers at 0.8-1.7 g/cc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adsorptive sheet having a deodorizing function, an air purification filter having a dust removing function and a deodorizing function, and a method for producing the adsorptive sheet.

[0002]

2. Description of the Related Art Conventionally, granular activated carbon has been generally used for purification and deodorization of gases and liquids because it is inexpensive, has good air permeability, and has a strong adsorption capacity for aerosols and solutes in a solution. It's being used.

[0003] As one of the techniques for applying such granular activated carbon to an air purification filter, there is a sheet-like adsorbent that uses air to be purified in a direction perpendicular to a sheet surface. However, the granular activated carbon in such a sheet-shaped adsorbent is not easy to form as a filtration membrane by itself, and even if a filtration membrane can be formed using any carrier, it is easy to form the filtration membrane from the carrier. There is a problem that it is peeled off and washed away. Under such circumstances, there is a demand for the development of a technology that can effectively use the granular activated carbon as a material for an air purification filter.

[0004] On the other hand, as the problem of dust contamination has increased, there has been a demand for a filter having a combination of a filter having a dust removing function and a filter having a deodorizing function as an air cleaning filter. However, the shape in which the dust filter and the deodorizing filter are separated and present separately has a problem of a space problem and a high cost.

[0005] As a technique for effectively using granular activated carbon as a material for an air purification filter, a method of supporting activated carbon on a nonwoven fabric, a net-like substrate, or a polyurethane foam is known at present.

For example, Japanese Patent Application Laid-Open No. 48-72088 discloses an adsorptive sheet obtained by attaching an adhesive to a nonwoven fabric and then spraying activated carbon. However, such adsorbent sheets require a large amount of adhesive to cover the entire surface of the non-woven fabric in order to firmly hold the activated carbon, resulting in high airflow resistance and relatively coarse dust such as pollen. , Sand, spike dust and the like are liable to cause early clogging.

[0007] Japanese Patent Application Laid-Open No. 9-285531 discloses that
Adsorbent sheet coated with a binder on the net-shaped substrate to reduce pressure loss, and then loaded with activated carbon.
JP-A-35201 discloses an adsorptive sheet in which a polyurethane foam is coated with a binder and then activated carbon is supported. However, in order to use such an adsorptive sheet as an actual filter, it is necessary to further overlap a sheet for preventing activated carbon falling off at least on the downstream side. Further, if the sheets are simply overlapped with each other, the sheet for preventing the activated carbon from dropping off during use due to wind pressure will need to be fixed in some way. As one of the methods, there is a method using an adhesive. However, in this method, the same phenomenon as described above eventually occurs, and the airflow resistance increases. As a method not using a binder, there is a confounding method using a needle punch. However, since the activated carbon has a weak supporting force, the activated carbon is more likely to fall off, thereby deteriorating the deodorizing performance and causing a practical problem.

Further, US Pat. No. 5,605,746 discloses a fibrous structure in which granular activated carbon or the like is fixed in a nonwoven fabric matrix formed of a composite fiber of a heat-fusible fiber and another fiber by heat fusion. Is disclosed. Further, as a method for manufacturing such a fiber structure, US Pat.
No. 339 discloses that an open fibrous web structure containing a heat-fusible fiber and other fibers is dry-formed and a granular activated carbon having an appropriate size and weight is dispersed and taken into the structure. After that, a production method is disclosed in which granular activated carbon or the like is fixed by heating and heat fusion.

However, in the method of fixing the granular activated carbon with the heat-fusible fibers as described above, it is generally difficult to reliably fix the granular activated carbon so as not to fall off. It was difficult to achieve both the strong retention of granular activated carbon and the adsorption performance and air permeability.

As described above, an adsorbent sheet or an air purification filter which holds granular activated carbon firmly, has excellent adsorption performance against odorous gas and bendability, has low pressure loss, and is unlikely to be clogged with dust. At present, no satisfactory products have been obtained.

On the other hand, in order to solve the problem of insufficient dust removal performance, various filters have been proposed in which a dust removal filter and a deodorizing filter are laminated and integrated.

For example, in Japanese Patent Application Laid-Open No. 4-74505, a dust filter using an electret non-woven fabric and a deodorizing filter in which granular activated carbon is dispersed in latex are bonded with a hot melt adhesive, and are integrally formed into a pleated shape. A filter is disclosed. However, the electretized nonwoven fabric disclosed in this publication is a so-called spunbond type electret nonwoven fabric, and this nonwoven fabric has an insufficient dust removing function. Also,
Clogging occurs at an early stage, and a sudden increase in pressure loss occurs, so that the filter life comes before the life of the deodorizing sheet comes, and there is a problem in terms of filter function and economy.

Japanese Patent Application Laid-Open No. Hei 7-265640 discloses a filter in which electret fibers are raised and dust is captured three-dimensionally to prevent clogging. However, the electret fiber disclosed in this publication is also a so-called spun-bond type electret filter, and has a low charge rate and cannot obtain a sufficiently satisfactory dust removal efficiency.

As described above, at present, there is no composite function (dust removing and deodorizing) filter which exhibits a sufficient dust removing effect and has a long filter life.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an adsorbent sheet having good air permeability and excellent retention of activated carbon.
An object of the present invention is to provide a filter for air purification, which maintains excellent dust removal performance for a long period of time, and a method for producing an adsorptive sheet thereof.

The present inventors have conducted various studies on the structure of holding granular activated carbon by fibers and the formation thereof in order to solve the above-mentioned problems. As a result, instead of fixing the activated carbon with an adhesive, the supporting fibers are substantially fixed. It has been found that by fixing the granular activated carbon by the method described above, an adsorbent sheet having both good fixing strength and good air permeability of the granular activated carbon can be obtained.

Further, it has been found that the above-mentioned sheet can be suitably produced by mixing the granular activated carbon and the supporting fibers and performing wet papermaking. At that time, in addition to the above-mentioned granular activated carbon and the supporting fiber, by adding a small amount of adhesive fiber, it has been found that the holding structure of the granular activated carbon by the supporting fiber can be made stronger and stable. .

Further, the present invention provides an adsorbent sheet wherein the deodorizing sheet and the electret nonwoven fabric are laminated and integrated, and the electret fibers are film split type electret fibers. The present invention also provides an air purification filter, characterized in that the above-mentioned adsorptive sheet is formed into a pleated or corrugated shape.

The present inventors have made further studies based on the above findings, and have reached the present invention.

[0020]

That is, the above object can be achieved by the present invention as follows.

The adsorptive sheet of the present invention is an adsorptive sheet having a granular activated carbon-containing sheet, wherein the granular activated carbon-containing sheet is in contact with the granular activated carbon having an average particle diameter of 60 to 600 μm and is fixed by contacting the granular activated carbon. Supporting fibers that
Adhesive fibers mainly contributing to shape retention. Instead of fixing the activated carbon with an adhesive, by fixing the activated carbon of a specific particle size substantially by the supporting fibers, it becomes possible to obtain an adsorbent sheet having both good fixing strength and good air permeability of the granular activated carbon. . In other words, the amount of the adhesive component such as an adhesive is minimized, and the original deodorizing performance of the granular activated carbon can be maximized, and at the same time, the ventilation resistance of the entire sheet can be kept low. Things.

In the above, it is preferable that the granular activated carbon-containing sheet comprises a surface layer having a smaller content of the granular activated carbon as compared with other portions, and a backside layer formed on the back side of the surface layer. By having such a surface layer, it is possible to bend, etc., in a state where it is difficult to touch the granular activated carbon, and by arranging the surface layer on the downstream side during ventilation, it is possible to more reliably prevent the granular activated carbon from flowing out it can. From such a viewpoint, it is more preferable to have a surface layer containing no granular activated carbon.

Preferably, the granular activated carbon-containing sheet is formed integrally by wet bonding using water-swellable fibers as the adhesive fibers. In such wet bonding, since the adhesion between the supporting fiber and the granular activated carbon during drying increases, the granular activated carbon is integrally and firmly fixed inside the sheet, and the granular activated carbon falls off during bending or the like extremely. It becomes possible to make it difficult.

It is preferable that the supporting fiber has an outer surface area of 1 m ² / g or less, a fiber length of 3 to 20 mm, and a density of 0.8 to 1.7 g / cc. Thereby, the air permeability, the adsorption performance, the paper making property, and the like of the obtained adsorptive sheet are improved.

It is preferable that the granular activated carbon-containing sheet contains 30 to 80% by weight of the granular activated carbon based on the total weight of the sheet. Thereby, the adsorption performance, strength, and the like of the obtained adsorptive sheet are improved.

It is preferable that the granular activated carbon-containing sheet has fine pores which can be substantially ventilated in the thickness direction. By forming such ventilation holes, the pressure loss can be further reduced, the amount of retained dust can be greatly improved, and the life of the suction sheet can be significantly improved.

[0027] At that time, the average open area per hole of said fine pores is preferably a 0.5 mm ² to 3 mm ^2. Further, it is preferable that the number of the fine holes is 1 to 20 per 1 cm ^{2 of the} granular activated carbon-containing sheet. Further, the opening ratio of the fine holes is 3% to 10%.
It is preferred that

In the present invention, it is preferable to include a breathable sheet in addition to the above-mentioned granular activated carbon-containing sheet.
This is because it is possible to more reliably prevent the granular activated carbon from falling off at the time of bending processing or at the time of use as a filter. In addition, considering the packing density in the sheet thickness direction, a coarse to dense state can be realized, and when dust is loaded from the upstream side, the dust can be retained relatively evenly in the sheet thickness direction, resulting in early clogging. Pressure rise due to the pressure can be suppressed. Therefore, it is preferable that the breathable sheet is laminated on the backside layer of the granular activated carbon-containing sheet.

In this case, it is preferable that the breathable sheet is mainly composed of a nonwoven fabric made of film split type electret fibers. Thereby, the removal effect on the submicron particles can be increased.

The breathable sheet further comprises a non-woven fabric,
It is preferable that a woven or net cover factor is provided. Thereby, the handleability as a filter, such as stabilization of dust removal efficiency, stabilization of the amount of retained dust, and prevention of flaking of a film split type electret fiber, can be further improved.

The packing density of the breathable sheet is as follows:
It is preferably 0.01 to 0.20 g / cc. Thereby, the air permeability, dust holding amount, strength,
The handling is further improved.

On the other hand, the air purification filter of the present invention
An air purification filter formed by molding the above adsorptive sheet into a pleated or wavy shape. Since this filter uses the adsorptive sheet of the present invention, it has good air permeability, excellent retention of activated carbon, and can maintain excellent dust removal performance over a long period of time. Furthermore, as described above, it is possible to increase the effective filtration area by forming a pleated or corrugated shape without causing the granular activated carbon to fall off during processing.

At this time, the thickness of the filter is 10 to 400
mm and the peak apex distance are preferably 2 to 30 mm.

On the other hand, the production method of the present invention is a method for producing an adsorptive sheet having a step of forming a granular activated carbon-containing sheet, wherein the step of forming the granular activated carbon-containing sheet comprises a step of forming a granular activated carbon having an average particle diameter of 60 to 600 μm. A step of preparing an aqueous slurry containing a supporting fiber, and a water-swellable adhesive fiber, and a step of developing the aqueous slurry in a planar state,
Mechanical dehydration and drying from the developed aqueous slurry.

According to this production method, the required amount of the adhesive component is extremely small, so that a granular activated carbon-containing sheet having low airflow resistance can be formed, and the characteristics of the granular activated carbon can be maximized. In addition, it is also possible to form a surface layer having a smaller content of granular activated carbon as compared with the backside layer by utilizing the difference in the sedimentation speed of the solid content.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the schematic structure of the adsorptive sheet of the present invention will be described with reference to the drawings.

FIG. 1 (A) is a schematic view of the adsorptive sheet of the present invention formed only of the granular activated carbon-containing sheet. The granular activated carbon-containing sheet according to the present invention comprises: granular activated carbon 1;
It includes support fibers that contact and fix the granular activated carbon 1 and adhesive fibers that mainly contribute to shape retention. Here, the supporting fiber and the adhesive fiber are illustrated as a mixed fiber component 2. In this embodiment, the content density of the granular activated carbon is higher toward the lower side of the drawing, and the content of the granular activated carbon 1 is smaller, preferably not contained, on the upper surface compared to the backside layer L2. L1 is formed. Such a structure can be formed by utilizing a difference in the sedimentation speed of solids in a papermaking process for performing wet bonding. In addition,
This figure schematically shows the structure of the adsorptive sheet of the present invention, and the present invention is not limited to such a simple structure.

FIG. 1B is a schematic view of the adsorptive sheet of the present invention further having a breathable sheet L3 and a cover factor of 4. In this embodiment, the breathable sheet L3 and the cover factor 4 are sequentially laminated on the back layer L2. Further, as a particularly preferable air-permeable sheet L3, a nonwoven fabric 3 made of film split type electret fibers is used. The arrow indicates the direction of the air flow in normal use.

The details of each constituent material will be described below.

The average particle size of the granular activated carbon used in the adsorptive sheet of the present invention is 60 to 600 μm on average according to a JIS standard sieve (JIS Z8801) in consideration of air permeability, falling off of the adsorbent, papermaking properties, and the like. Preferably 10
More preferably, it is 0 to 500 μm. Average particle size is 6
If it is less than 0 μm, the pressure loss becomes too large to obtain a constant high adsorption capacity, and the sheet packing density tends to be high at the same time, which may cause an early rise in pressure loss during dust supply. When the average particle size exceeds 600 μm, the particles are apt to fall off, and the initial adsorption performance in one pass is extremely low, and furthermore, the pleated and honeycomb-shaped air purification filters are bent, and The workability at the time of corrugation is deteriorated.

The above-mentioned granular activated carbon can be obtained by performing a predetermined particle size adjustment using an ordinary classifier.

The type of the granular activated carbon used in the adsorptive sheet of the present invention is not particularly limited.
Coconut-based, wood-based, coal-based, pitch-based and the like are preferably used. In addition, crushed charcoal, granulated charcoal, bead charcoal and the like are suitably used as the above granular activated carbon.

The toluene adsorption of the granular activated carbon used in the adsorptive sheet of the present invention as measured according to JIS K1474 is preferably 20% by weight or more. This is because high adsorption performance is required for nonpolar gaseous and liquid substances such as odorous gas.

The granular activated carbon used in the adsorptive sheet of the present invention may be subjected to a chemical treatment for the purpose of improving the adsorption performance of polar substances. Chemicals used for gas chemical treatment include aldehyde gas, nitrogen compounds such as NOx, sulfur compounds such as SOx, and acidic polar substances such as acetic acid, for example, ethanolamine, polyethyleneimine, aniline, P- Amine drugs such as anisidine and sulfanilic acid, sodium hydroxide, potassium hydroxide, guanidine carbonate, guanidine phosphate, aminoguanidine sulfate, 5,5-dimethylhydantoin, benzoguanamine, 2,2-iminodiethanol, 2,2 2-
Nitrotriethanol, ethanolamine hydrochloride, 2-
Aminoethanol, 2,2-iminodiethanol hydrochloride, p-aminobenzoic acid, sodium sulfanilate,
L-arginine, methylamine hydrochloride, semicarbazide hydrochloride, hydrazine, hydroquinone, hydroxylamine sulfate, permanganate, potassium carbonate, potassium bicarbonate and the like are preferably used, and ammonia, methylamine,
For basic polar substances such as trimethylamine and pyridine, for example, phosphoric acid, citric acid, malic acid, ascorbic acid and the like are preferably used. The chemical treatment is carried out, for example, by supporting or impregnating the granular activated carbon with a chemical. In addition to directly treating the activated carbon with the chemical, it is also possible to perform a method of applying an ordinary coating method or the like to the vicinity of the surface of the sheet or to impregnate the entire sheet.

The granular activated carbon-containing sheet contained in the adsorptive sheet of the present invention preferably contains 30 to 80% by weight of granular activated carbon. If the amount is less than 30% by weight, good adsorption performance cannot be obtained, and if it exceeds 80% by weight, the strength of the adsorptive sheet decreases.

The granular activated carbon-containing sheet contained in the adsorptive sheet of the present invention preferably contains 5 to 50% by weight of supporting fibers. If the content is less than 5% by weight, the papermaking properties deteriorate,
If it exceeds 50% by weight, the adsorption effect becomes poor.

The outer surface area of the supporting fibers used in the adsorptive sheet of the present invention is preferably 1 m ² / g or less. If it exceeds 1 m ² / g, the air permeability and papermaking properties will be reduced.

As the above supporting fibers, both fibrillated fibers and non-fibrillated fibers are used.

The fiber length of the support fiber used in the adsorptive sheet of the present invention is preferably 3 to 20 mm. Three
If it is less than 20 mm, the air permeability will be poor, and if it exceeds 20 mm, the papermaking properties and the formation of the sheet will be poor, and the variation in air flow resistance and adsorption performance will be large.

The specific gravity of the supporting fibers used in the adsorptive sheet of the present invention is preferably 0.8 to 1.7 g / cc. When the specific gravity is less than 0.8 g / cc, the support fiber and the granular activated carbon are separated and formed at the time of producing the papermaking slurry, so that a dense layer of the support fiber is formed on the surface layer,
The pressure loss is increased, and the retention of the granular activated carbon by the supporting fibers becomes insufficient, and the falling off of the granular activated carbon is increased. If the specific gravity exceeds 1.7 g / cc, the difference in specific gravity from granular activated carbon (specific gravity of about 1.8) is small, so that a surface layer is not formed and the original purpose cannot be achieved.

As the above-mentioned supporting fibers, those having hydrophilicity are preferred. This is because the activated carbon-containing sheet is formed more strongly.

The material of the support fiber used in the adsorptive sheet of the present invention is not particularly limited. For example, in addition to synthetic fibers such as polyester, polyacrylonitrile, polyamide, and polyolefin, linter, cotton, hemp, and wood Pulp, rayon, glass fiber and the like are used. Preferably, it is wood pulp, rayon, polyester, polyolefin, or polyamide.

The fiber shape may be a concentric circle or an irregular cross section. Cracked fibers can also be used.

The adhesive fiber used in the adsorptive sheet of the present invention may be any one that becomes an adhesive component (binder) at the time of compounding, such as a water-swellable fiber or a hot-melt fiber.
Polyvinyl alcohol fiber, polyethylene fiber, polypropylene-polyethylene, polyester composite fiber, polyamide composite fiber and the like are preferably used.

Further, these fibers may have a sea core structure, a side-by-side structure, or a crumpled fiber.

The specific gravity of the adhesive fiber used in the adsorptive sheet of the present invention is preferably 0.8 to 1.7 g / cc, and in particular, the specific gravity of the support fiber is almost the same (± 10%).
%). After making the papermaking slurry,
This is because it is present in the vicinity of the supporting fiber and improves the shape retention of the surface layer and the backside layer of the granular activated carbon-containing sheet.

The fiber length of the adhesive fiber used in the adsorptive sheet of the present invention is preferably 1 to 20 mm.
If it is less than 1 mm, the air permeability will be poor, and if it is more than 20 mm, the papermaking properties and the formation of the sheet will be poor, and the variation in air flow resistance and adsorption performance will be large.

The mixing ratio of the adhesive fiber used in the adsorptive sheet of the present invention is preferably 1 to 30% by weight, and 5 to 2% by weight.
0% by weight is more preferable. When the amount is less than 1% by weight, the function as an adhesive component cannot be exhibited, and
If it exceeds 0% by weight, the adsorptivity is relatively reduced,
Pressure drop also increases.

The adsorptive sheet of the present invention may be constituted to include components having ancillary functions such as an antibacterial agent, an antifungal agent, an antiviral agent and a flame retardant. These components may be kneaded into the fibers, or may be added and supported by post-processing. For example, by including a flame retardant, F
MVSS. The standard for the low-flammability and UL specified in 302
It is possible to manufacture an adsorptive sheet that meets flame retardant standards.

The components having the above-mentioned additional functions may be impregnated or supported on granular activated carbon. However, in this case, care must be taken not to impair the original adsorption function of the granular activated carbon.

It is also possible to enhance the deodorizing function by using fibers having an adsorbing performance for fibers, for example, ion exchange fibers.

The thickness of the adsorptive sheet of the present invention is from 0.3 to
2.5 mm is preferred. This is for improving the air permeability and workability.

The basis weight of the adsorptive sheet of the present invention is 50 g /
m^Two More preferably, 200 g / m ^Two If it is more than
Higher adsorption capacity can be realized, and the removal effect is more
This is preferable because it can be twisted.

The packing density of the adsorptive sheet of the present invention is 0.1.
It is preferably 15 to 0.3 g / cc, and 0.17 to
More preferably, it is 0.25 g / cc. 0.15g /
If it is less than 0.3 cc, the dust removal efficiency becomes low,
If it exceeds g / cc, clogging causes an early rise in pressure loss, which is not preferable as a filter.
In order to adjust the sheet density to such a value, it is more preferable to mix a suitable amount of a fiber having a fiber diameter of 15 μm or more into the supporting fiber because it is easy to provide a gap between the fiber and the activated carbon.

The granular activated carbon-containing sheet contained in the adsorptive sheet of the present invention can be produced by various methods, and the production method of the present invention can be applied as a particularly preferable one. The production method of the present invention is a method for producing an adsorptive sheet having a step of forming a granular activated carbon-containing sheet, wherein the step of forming the granular activated carbon-containing sheet has an average particle diameter of 60 to 600 μm
Granulated activated carbon, supporting fibers, a step of preparing an aqueous slurry containing water-swellable adhesive fibers, a step of developing the aqueous slurry in a plane, mechanical dehydration and drying from the developed aqueous slurry And performing the following. A preferred embodiment will be described with reference to FIG.

The aqueous slurry is usually prepared by a conventional method using water or an aqueous solution as a dispersion medium, and supplied from the bottom of the container 12. The supplied aqueous slurry is spread on the upper surface of the endless belt 11, and is mechanically dehydrated gradually while being conveyed to form a wet web 18. At that time, as the mechanical dehydration, long net type, short net type,
Circular mesh method or the like can be adopted.
It is also possible to squeeze lightly at 3, 14 or to perform suction dehydration.

Thereafter, the sheet is conveyed to the rotary drying drum 6 by the endless belt 15 for conveying the sheet, and is contact-dried by the rotary drying drum 16 to form the adsorptive sheet 19. By continuously performing a series of steps while winding the adsorptive sheet 19 with the take-up roll 17, the adsorptive sheet of the present invention can be manufactured as a continuous product. At the time of the above, the yield can be improved by adding an appropriate amount of a polymer-based or inorganic-based dispersant or coagulant to the slurry.

On the other hand, the adsorptive sheet of the present invention can also be produced by a method in which the slurry is poured into a mold or resin mold having a hole having air permeability, followed by suction and drying. Alternatively, a nonwoven fabric web containing support fibers and adhesive fibers may be prepared in advance, activated carbon may be dispersed therein, and then a sheet may be formed by blowing hot air. However, in consideration of the uniform dispersibility of the activated carbon and the like, it is more preferable to produce the activated carbon through the above-described step of dispersing in water. As described above, the characteristics of the adsorptive sheet of the present invention can be further improved by forming vents substantially in the thickness direction of the adsorptive sheet.

The vent hole may or may not penetrate the adsorptive sheet, and is a hole provided in the thickness direction of the adsorptive sheet, and is a hole which can substantially ventilate. I just need.

The average opening area per hole of the air holes formed in the adsorptive sheet of the present invention is 0.5 mm ^{2 to 3} m.
m ² is preferable, and 1 mm ² to ² mm ² is more preferable. When the average opening area is less than 0.5 mm ² , the effect of reducing airflow resistance and reducing clogging against dust is small. If the average opening area exceeds 3 mm ² ,
There is a possibility that the granular activated carbon may not be sufficiently adhered, and the granular activated carbon may fall off.

The average opening area per hole was measured by measuring a sample of 1 cm square from any three points of the adsorptive sheet, using a microscope equipped with an area measuring function, such as Keyence Corporation. The measurement is performed using a high-definition digital microscope VH-6300.

The opening ratio of the air holes formed in the adsorptive sheet of the present invention is preferably 3% to 10%, preferably 5%.
It is more preferable if it is ８8%. If the opening ratio is less than 3%, the effect of reducing pressure loss and reducing clogging against dust is small. If the opening ratio exceeds 10%, the granular activated carbon is not sufficiently fixed, and the granular activated carbon may fall off.

The aperture ratio is determined by the following formula by calculating the sum of the aperture areas of samples of a 1 cm square from any three points of the adsorptive sheet.

Opening ratio (%) = Total opening area / sample area × 100 In consideration of the average opening area and the opening ratio as described above,
The number of fine pores formed in the adsorptive sheet is 1 to 20, especially 5 to 1 per cm ^{2 of the} granular activated carbon-containing sheet.
The number is preferably five.

The method for opening the air holes formed in the adsorptive sheet of the present invention is not particularly limited, and a method using a needle punching method, an air punching method, a water entanglement method or the like alone or in combination may be used. It is preferably used. Also,
The shape of the opening is also not particularly limited, and is cylindrical,
A conical shape or the like is preferably used.

The adsorptive sheet of the present invention has very little activated carbon falling off as it is and has low ventilation resistance, high deodorizing performance and high dust removal performance. It is preferable to laminate functional sheets for the above-mentioned reason.

The type of the breathable sheet used for the adsorptive sheet of the present invention is not particularly limited, and for example, a non-woven fabric, a woven fabric, a knitted fabric and the like are suitably used.

The material of the breathable sheet used for the adsorptive sheet of the present invention is not particularly limited, and examples thereof include wood pulp, rayon, acetate, polyester, polyacrylonitrile, polyamide, polypropylene, polyethylene, and polyclar. They can be used alone or as a mixture.

As the air-permeable sheet used in the adsorptive sheet of the present invention, if a permanently charged so-called electret sheet is laminated, submicron particles such as tobacco smoke particles, carbon particles and sea salt particles can be used. The removal effect on the particles can also be increased. As a method of obtaining such an electretized sheet, a film made of a material that can be electretized is formed into a nonwoven fabric and subjected to corona charging treatment, or a film formed by forming the electretized film into split fibers and forming a nonwoven fabric Although a known method such as a split method can be used, it is particularly preferable to use a film split method which has a high charging efficiency, can be formed into a sheet in a bulky state, and can reduce a pressure loss.

The material of the film split type electret fiber used in the present invention is not particularly limited. For example, polyolefin polymers such as polypropylene, polyethylene and syndiotactic polystyrene, and α such as poly-4-methyl-1 pentene -Polyolefin-based polymers, fluorine-based polymers such as Teflon, polycarbonate, polyester and the like are preferably used.

The method for producing the film split type electret fiber used in the present invention is not particularly limited. For example, a cast film is prepared from the above resin by melt extrusion, and then the film is formed into a 5-1 to 1: 1 film.
A stretched film is formed by stretching the film vertically or horizontally by a factor of 0, then electretized by charging, and then split by an opening cutter.

The stretching film can be charged by a charging method such as corona discharge, electric field discharge, electron beam irradiation, or triboelectric charging alone or in combination. As a method for splitting the electret film, a method using a needle type cutter, a screw type cutter, a blade type cutter or the like is used.

The average split width of the film split type electret fiber used in the present invention is preferably from 10 μm to 500 μm, more preferably from 20 μm to 3 μm.
00 μm, most preferably 40 μm to 200 μm.

The electret film of the film split type electret fiber used in the present invention preferably has a thickness of 3 μm to 30 μm.

The surface charge density of the film split type electret fiber used in the present invention preferably has a maximum surface charge density represented by the Loose equation.
It is not limited to that.

The packing density of the film split type electret fibers in the dust removing sheet used in the present invention, which is determined by the following formula, is preferably 0.01 to 0.20 cc / cc. When it exceeds 0.20 cc / cc, the density is further increased due to the pressing in the step of integration with the deodorizing sheet, and the ventilation resistance is increased. If it is less than 0.01 cc / cc, it is difficult to maintain a stable density, and it is difficult to handle in terms of strength.

The above packing density refers to the packing density of the film split type electret fibers in the dust removal sheet, and is calculated by the following equation.

Packing density (cc / cc) = (W × 10 ⁻⁴ ) / (T × ρ) where W: weight of fiber layer (g / m ² ) T: thickness of fiber layer (cm) ρ: Fiber Density (g / cc) The weight of the film split type electret fibers in the dust removal sheet used in the present invention is preferably 5 to 250 g / m ² . When the basis weight is less than 5 g / m ² , the dust collection efficiency is low, and when the basis weight exceeds 250 g / m ² , clogging is likely to occur.

The film split type electret fiber used in the present invention may contain an additive for improving the chargeability. The additive used here is not particularly limited, and for example, sodium bis (4-t-butylphenyl) phosphate, sodium 2,2′-ethylidenebis (4,6-di-t-butylphenyl) phosphate A resin modifier such as tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate;
1,3-tris (2-methyl-4-hydroxy-5-t
-Butylphenyl) butane, 1,1, bis (2'-methyl-4hydroxy-5'-t-butylphenyl) butane, 2,2-thio-diethylenebis [3- (3,5-di-t- Butyl-4-hydroxyphenyl) polopionate], 3,9-bis [2- {3-tert-butyl-4-hydroxy-5-methylphenyl {propionyloxy}-
1,1-dimethylethyl] -2,8,10-tetraoxaspiro [5,5] undecane, bis (2,4-di-t
-Butylphenyl) pentaerythritol diphosphite, bis (2,6-di-butyl-4-methylphenyl)
Pentaerythritol diphosphite, ethylidenebis (4,6-di-t-butylphenyl) octyl phosphite, tris- (2,4-di-t-butylphenyl)
Antioxidants such as phosphites, heavy metal deactivators such as 3- (N-salicyloyl) amino-1,2,4-triazole, decanedicarboxylic acid disalicyloyl hydrazide, 2- (2'-hydroxy- 5'-methylphenyl)
Benzotriazole, 2- (2'-hydroxy-3'-
t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylenebis [4- (1,
1,3,3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol], bis (5-
Benzoyl-4-hydroxy-4-piperidyl) -1,
2,3,4-butanetetracarboxylate, 1,2,2
2,6,6-pentamethyl-4-piperidyl / β, β,
β ′, β′-tetramethyl-3,9- [2,4,8,1
Light stabilizers such as 0-tetraoxaspiro (5,5) undecane] diethyl (mixed) -1,2,3,4-butanetetracarboxylate, magnesium stearate,
Fatty acid metal salts such as aluminum stearate and aluminum laurate are preferably used.

The amount of these additives varies depending on the type of the additives, but is effective in the range of 0.05 to 5% by weight based on the weight of the film split type electret fiber.

As described above, it is more preferable that the dust removal sheet used in the present invention has a cover factor. As the form of the cover factor, non-woven fabric,
A woven or net-like substrate is preferably used.

As a method of providing the cover factor, the cover factor and a nonwoven fabric mainly composed of the above-mentioned film split type electret fiber are laminated and integrated by a mechanical entanglement method such as a needle punch method or an air punch method. do it.

The material of the cover factor is not particularly limited, and examples thereof include polyamide, polypropylene, rayon, polyester, polytetrafluoroethylene, polyvinyl alcohol, polyacrylonitrile, polyclar, and polyethylene.

The basis weight of the cover factor is as follows:
Possible low basis weight is preferably to make use as much as possible high dust removal ^{rate, 5g / m 2 ~100g / m} 2 is preferred.

It is further preferable that heat-fused fibers are mixed into the cover factor and fused with the adjacent fibers, because fluffing can be further suppressed.

In this case, various shapes such as a round cross section and a short cross section are used for the cross section of the heat-fused fiber. The heat-fused fiber may be a single-component resin or a multi-component resin. Examples of the multi-component heat-fusible fiber include a cross-sectional shape having a side-by-side structure or a sea core structure. For example, for a fiber having a sheath core structure, a resin having a lower melting temperature in the sheath portion than in the core portion is used.
Examples of such a combination include a combination of a sheath made of polyethylene or ethylene-vinyl acetate copolymer, a core made of polypropylene, a sheath made of a copolymer polyester having a low melting temperature, and a combination made of a polyethylene terephthalate core. By combining resins having different melting temperatures in this way and forming fibers having a low melting temperature on the fiber surface, only the surface portion is melted at a predetermined temperature, and the shape of the internal fibers can be maintained as it is. Also, of course, a plurality of these fiber layers may be laminated.

The non-woven fabric mainly composed of film split type electret fibers used in the present invention includes antibacterial fibers, deodorized fibers, aromatic fibers, flame-retardant fibers, and spun bond type or melt blown type electret filters. Fiber or non-woven fabric may be mixed within a range that does not lose the function of the fiber layer.

The packing density of the dust removing sheet used in the present invention is preferably 0.01 to 0.20 g / cc, and is preferably 0.02 to 0.20 g / cc.
It is more preferable if it is 0.15 g / cc. 0.20g
If it exceeds / cc, the pressure loss increases and the dust holding amount decreases. If it is less than 0.01 g / cc, the strength is weak, and the handleability is poor.

The packing density of the dust-removing sheet refers to the packing density of the film-split type electret fibers, cover factors, and other additives constituting the dust-removing sheet, and is calculated by the following equation.

Packing density (g / cc) = weight of dust-removing sheet (g / cm ² ) / thickness of dust-removing sheet (cm)
It is determined as the difference between the thickness of the adsorptive sheet and the thickness of the deodorizing sheet when a pressure of 0 gf / cm ² is applied.

In the adsorptive sheet of the present invention, the method of laminating the granular activated carbon-containing sheet and the gas permeable sheet is not particularly limited, and may be, for example, simple lamination, application of a small amount of adhesive, Alternatively, a bonding method utilizing heat-fusibility, for example, a method of spraying a bonding fiber onto a body to be bonded, a method of inserting and bonding an adhesive sheet between the sheets, a method of bonding by bonding by ultrasonic waves, a needle punch, A method that does not use a binder, such as an air punch or a hydroentanglement method, may be used. In any case, since the air-permeable sheet is disposed on the upstream side, the air-permeable sheet is not easily peeled off by the wind pressure, and does not require very strong adhesion.

The air purifying filter of the present invention is preferably formed by molding the above-described adsorptive sheet into a pleated or corrugated shape.

The thickness of the molded air purification filter is preferably from 10 to 400 mm. For car-mounted air conditioners and other home-use air purifiers, such as those installed inside car air conditioners, the size of ordinary filter units is 10 to 60 mm. About 400 mm is preferable in consideration of the storage space.

It is preferable that the crest peak interval of the air purification filter of the present invention is 2 to 30 mm. If it is less than 2 mm, the folds and mountains will be too close together and there will be many dead spaces, making it impossible to use the seat efficiently. On the other hand, when the thickness is 30 mm or more, the sheet development area becomes small, so that a removal effect corresponding to the filter thickness cannot be obtained.

In the air purifying filter of the present invention, in the case where the air purifying filter is integrated with the air permeable sheet, it is more preferable that the surface layer of the granular activated carbon-containing sheet is disposed downstream of the back side layer. By doing so, the integrated breathable sheet becomes more difficult to peel off.

[0106]

The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the present invention. It is included in the technical range of.

The numerical values in the examples are values measured by the following method.

(1) JIS Class 15 Dust Retention Amount was supplied using the following mixed powder under the conditions of a linear velocity of 30 cm / s and a supply concentration of 0.5 g / m ^3.
The life when the pressure increased by 50 Pa was judged to be the life, and the amount of dust deposited on the filter medium at that time was weighed with a balance. This value indicates a substitute characteristic of the degree of clogging for dust.

Composition of mixed powder 8 kinds of JIS (average about 8 μm, Kanto loam) 72% by weight Carbon black (average about 0.1 μm) 23% by weight Cotton linter (average about 1.5 μm) 5% by weight (2) Airflow resistance The pressure loss at the time of ventilation at a linear velocity of 30 cm / s was measured.

(3) Particle removal efficiency The particle concentration of the upstream and downstream of the filter was measured using a 0.3 μm NaCl particle at a linear velocity of 30 cm / s with a particle counter (manufactured by Lion, KC-01C).
It is shown as a percentage of the value obtained by subtracting the downstream particle concentration from the upstream particle concentration by the upstream particle concentration.

(4) Sheet filling density Sheet filling density (g / cc) = sheet weight / sheet thickness [sheet thickness is a value under a load of 180 gf / cm ² ] (5) Peeling of reinforcing sheet Linear velocity 30 cm / s Under these conditions, the peelability of the reinforcing sheet from the main sheet was also compared.

Example 1 Average particle size 310 μm, JIS
The toluene adsorption capacity measured by the K 1474 method is 4
70 parts by weight of granular activated carbon of 70 mg / g, 18 parts by weight of rayon fiber of 8 denier × 8 mm in fiber length, and 12 parts by weight of polyvinyl alcohol of 1 denier × 3 mm in fiber length, which is a hydrothermally fusible fiber, were pulverized into water. To prepare a stock solution for wet papermaking. Using the apparatus shown in FIG. 2, this was made into a wet web by a fourdrinier papermaking method, then lightly squeezed with a press roller, dried at 140 ° C. with a rotary drying drum, and weighed at 300 g / m ² . Packing density 0.
A low packing density adsorption sheet of 21 g / cc was obtained. This sheet has a difference in sedimentation speed due to the difference in specific gravity between granular activated carbon, rayon (specific gravity of about 1.5), and polyvinyl alcohol (specific gravity of about 1.3) on a papermaking screen. As a result, the activated carbon-containing layer (backside layer) A surface layer composed of the supporting fibers and the adhesive fibers was formed.

When the backside layer of this sheet was disposed upstream and the pressure loss was measured, the sheet had a very low pressure of 30 Pa, and the amount of toluene adsorbed was 33% of the sheet weight, resulting in a sheet having a very high adsorption capacity. Moreover, the granular activated carbon did not fall off during use as a filter, and the handleability was very excellent. Furthermore, it should be noted that when a dust load of JIS type 15 was applied, the pressure loss rise until reaching the final pressure was very slow and clogging was difficult, and finally dust of as much as 40 g / m ² could be retained. That is, the sheet is excellent not only in the deodorizing function but also in the dust removing function. In addition, this sheet was filtered with a reciprocating type folding machine with a filter thickness of 40 mm and a ridge peak spacing of 7 m.
When processed into a filter unit with pleats of m, no cracks are formed at the folds of the folds. This filter is solid, and does not collapse even when a surface wind speed of 4 m / s is applied from the fold side. It was found to be excellent in handling properties and excellent in handling properties.

Example 2 Average particle size 310 μm, JIS
The toluene adsorption capacity measured by the K 1474 method is 4
70 parts by weight of granular activated carbon of 70 mg / g, 10 parts by weight of rayon fiber of 8 denier x fiber length of 8 mm, 12 parts by weight of fibrous polyvinyl alcohol of 1 denier x fiber length of 3 mm, sheath core structure and 110 on the sheath side 8 parts by weight of a polyester composite fiber having a melting point of 2 ° C. and a denier of 2 mm and a fiber length of 5 mm was dispersed in water with a pulper to prepare a stock solution for wet papermaking. This is made into a wet web by making a fourdrinier papermaking method, and then lightly squeezed with a press roller to 140 ° C.
To obtain a low filling density adsorption sheet having a basis weight of 400 g / m ² and a sheet filling density of 0.18 g / cc. This sheet was able to form a surface layer composed of an activated carbon-containing layer (backside layer), a supporting fiber, and an adhesive fiber layer due to the difference in the sedimentation speed as in Example 1.

When the backside layer of this sheet was arranged on the upstream side and the airflow resistance was measured, it was extremely low at 32 Pa, and the amount of toluene adsorbed was 33% of the sheet weight, resulting in a sheet having a very high adsorption capacity. Moreover, the granular activated carbon did not fall off during use as a filter, and the handleability was very excellent. Furthermore, it should be noted that when a dust load of JIS 15 type was applied, the pressure loss rise until reaching the final pressure was very slow, and clogging was difficult, and finally dust of 38 g / m ² could be retained. That is, it can be said that the sheet has not only a deodorizing function but also a dust removing function. Also, in order to confirm the actual effect of this adsorptive sheet, filter front size 200
A pleat having a size of 180 mm × 180 mm, a filter thickness of 40 mm, and a ridge peak interval of 7 mm was processed. In the air conditioner mode, the outside air is introduced and the surface wind speed is 1m /
It was operated in a steady state (AUTO) of about s. The air-conditioning capacity did not change much compared to when the filter was not installed, but when following the vehicle 10 meters behind the diesel exhaust vehicle, all the passengers in the vehicle (4 panelists) did not feel the unpleasant odor peculiar to diesel exhaust. .

Example 3 The granular activated carbon had an average of 130 μm.
m, a deodorized sheet having a basis weight of 170 g / m ² was produced in the same manner as in Example 2 and at the same ratio of supporting fibers and adhesive fibers. When the backside layer of this sheet was disposed on the upstream side and the pressure loss was measured, the sheet had a very low pressure of 28 Pa, and the amount of toluene adsorbed was 33% of the sheet weight, resulting in a sheet having a very high adsorption capacity. Moreover, the granular activated carbon did not fall off during use as a filter, and the handleability was very excellent.
Furthermore, it should be noted that when a dust load of JIS 15 type was applied, the pressure loss rise until reaching the final pressure was very slow, and the clogging was not easily performed. Finally, dust of 41 g / m ² could be retained. That is, it can be said that the sheet has not only a deodorizing function but also a dust removing function.

Comparative Example 1 A low pressure loss nonwoven fabric made of polypropylene having a basis weight of 20 g / m ² and a permeation resistance of 5 Pa was 10%.
Butadiene-acrylonitrile aqueous dispersion was sprayed, and after simple drying, 210 g of the same activated carbon as in Example 1 was supported.
The airflow resistance of this sheet was extremely high at 60 Pa. In addition, when JIS type 15 dust was loaded, the pressure loss rose early, and finally only 10 g / m ^{2 of} dust could be retained.

Comparative Example 2 An acrylonitrile-butadiene-based latex emulsion was immersed as a binder in a polypropylene net having a pressure loss of 2 Pa and having a basis weight of 50 g / m ² and a mesh size of 4 × 4 mm, and was lightly squeezed between rubber rolls. Activated carbon similar to that in Example 1 was carried, and further squeezed between rubber rolls, and then excess activated carbon was blown off by air blow. Although the airflow resistance of this sheet was as low as 30 Pa, the activated carbon fell off so much that it could not be used as a practical filter. The basis weight used in Comparative Example 1 to prevent falling off of activated carbon 20
g / m ² polypropylene nonwoven fabric was integrated with the needle punch on the downstream side by a method, but the activated carbon fell off greatly, and the nonwoven fabric peeled off during use.
It was not very usable.

Table 1 shows the results.

[0120]

[Table 1] (Production Example of Dust Removal Sheet) The following electret-made dust removal sheet was produced.

Dust Removal Sheet A A unit made of polypropylene (containing 0.3% of aluminum laurate) electret film split fiber having a thickness of 8.5 μm and an average split width of 65 μm 3 alone.
An electret split fiber layer of 0 g / m ² was produced. Although the fiber layer had a very low pressure loss of 7 Pa, the particle removal efficiency was very large at 40%.

Dust Removal Sheet B Electret film split fiber made of polypropylene (containing 0.3% of aluminum laurate) having a thickness of 8.5 μm and an average split width of 65 μm has a basis weight of 30 g.
/ M ² of electret split fiber layer and 4 denier heat-fused fiber having a sheath of copolymerized polyester and a core of polyethylene terephthalate, and a basis weight of 10 g / m ^2.
And a punch density of 50 punches / inch
Perform needle punching in ² and then 30
Heat treatment was performed in a hot air oven for 2 seconds to produce a film split type electret fiber layer A. Although the airflow resistance of this fiber layer was as low as 8 Pa, the particle removal efficiency was as large as 40%.

Dust Removal Sheet C Electret film made of polypropylene (containing 0.3% of aluminum laurate) having a thickness of 8.5 μm and an average split width of 65 μm Split fiber 30 g
/ M ² electret split fibers and a dry nonwoven fabric having a basis weight of 15 g / m ^{2 made} of 4-denier polypropylene were needle-punched to prepare a film split type electret fiber layer B. The pressure loss of this fiber layer is 8Pa
Although it was very low, the particle removal efficiency was very large at 41%.

Example 4 A deodorizing sheet having a basis weight of 350 g / m ² was prepared by the production method described in Example 2, and A was added to the back side layer.
950 g / 5 at 25 ° C as specified in STM D2979
After spraying 4 g / m ² of an adhesive having a fiber diameter of 50 μm and having a probe tack of mmφ, the dust removing sheet A was superimposed, lightly sandwiched between press rollers, and then press-bonded at room temperature to be integrated to produce an integrated dust removing and deodorizing sheet. The dust-removing sheet side of this sheet had some fluffing, but this was not a practical problem.

(Example 5) ASTM D297 was applied to the backside layer of the deodorizing sheet (having a basis weight of 170 g / m ² ) described in Example 3.
After spraying 4 g / m ² of an adhesive with a fiber diameter of 50 μm having a probe tack of 950 g / 5 mmφ at 25 ° C. specified in 9 and then superimposing the dust removal sheet B, lightly sandwiching it between press rollers and pressing at room temperature to integrate Then, an integrated sheet for dust removal and deodorization was produced. There was almost no fluff on both sides of this sheet, and the sheet was excellent in handleability.

In terms of characteristics, not only the airflow resistance is as low as 40 Pa, but the particle removal efficiency is as high as 39%, and the pressure loss rise until the final pressure is reached when a dust load of JIS 15 class is applied. Was very loose and hardly clogged, and as much as 50 g / m ^{2 of} dust could be retained before reaching the final pressure. Also, in order to confirm the actual effect of this sheet more specifically, a filter front size of 200 mm × 1
80mm, filter thickness 40mm, ridge peak interval 8m
m pleat shape (sheet development area 0.36m
² ) Furthermore, a frame material for fixing the end face was attached to make a unit, which was installed inside the car air conditioner. JIS of this unit
The retention amount of the 15 types of dust was 17 g per unit.
It is said that the amount of dust flowing from the outside air of the automobile filter per year depending on the location is about 10 g, which can be said to be effective for 1.7 years.

(Example 6) After the dust removal sheet C was superimposed on the back layer of the deodorizing sheet described in Example 3, the punch density was 50 punches / inch using a usual needle punching apparatus.
² . To perform needle punching and integrated. There was almost no occurrence of fluff and the like, and the performance was as good as in Example 3. It should be noted that a moderate air hole penetrated by needle punching through the entire sheet could be provided, which was smaller than the integrated value of the pressure loss measured independently for each of the deodorizing sheet and the film split type electret fiber layer. , Lower pressure loss.

(Example 7) The deodorized sheet described in Example 3 was prepared by using a needle punch device with an average opening area of 1.2 mm.
^2. A hole having an opening ratio of 5% was formed, and the ventilation resistance of the obtained sheet was measured. On the other hand, when the deodorizing performance was measured, the toluene adsorption amount was maintained at 33% of the sheet weight. Moreover, the granular activated carbon did not fall off during use as a filter, and the handleability was very excellent. Also noteworthy is JIS15
When a seed dust load is applied, the pressure loss rise until reaching the final pressure is very slow, and the clogging is not easily performed.
We were able to hold the m ² things dust. That is, it can be said that the low pressure loss and the dust removing function have been further improved while maintaining the deodorizing function.

Table 2 shows the above results.

[0130]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a schematic view of the adsorptive sheet of the present invention, wherein (A)
Is formed only of the granular activated carbon-containing sheet, (B)
Has a breathable sheet and a cover factor

FIG. 2 is a schematic explanatory view showing an example of an apparatus configuration when the adsorptive sheet of the present invention is manufactured by a fourdrinier papermaking method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Granular activated carbon 2 Fiber component (support fiber, adhesive fiber) 3 Nonwoven fabric 4 Cover factor L1 Surface layer L2 Backside layer L3 Breathable sheet 18 Wet web 19 Adsorbent sheet

Claims (17)

[Claims] 1. An adsorptive sheet having a granular activated carbon-containing sheet, wherein the granular activated carbon-containing sheet comprises: a granular activated carbon having an average particle diameter of 60 to 600 μm; and a supporting fiber fixed in contact with the granular activated carbon. Adsorbent sheet containing adhesive fibers that contribute to shape retention. 2. The granular activated carbon-containing sheet comprises a surface layer and a backside layer formed on the back side thereof, and the surface layer has a lower content of the granular activated carbon than the backside layer. The adsorptive sheet according to claim 1. 3. The adsorptive sheet according to claim 1, wherein the granular activated carbon-containing sheet is formed integrally by wet bonding using water-swellable fibers as the adhesive fibers. 4. The support fiber according to claim 1, wherein an outer surface area of the support fiber is 1 m ² / g or less, a fiber length is 3 to 20 mm, and a density is 0.8 to 1.7 g / cc. An adsorptive sheet according to any of the claims. 5. The adsorptive sheet according to claim 1, wherein the granular activated carbon-containing sheet contains 30 to 80% by weight of the granular activated carbon based on the total weight of the sheet. 6. The adsorptive sheet according to claim 1, wherein the granular activated carbon-containing sheet has fine pores which can be substantially ventilated in a thickness direction thereof. 7. An average opening per one hole of the fine holes.
Area is 0.5mm ^Two ~ 3mm^Two 7. The method according to claim 6, wherein
Adsorbent sheet. 8. The number of the fine holes is 1 to 20 per 1 cm ^{2 of the} granular activated carbon-containing sheet.
Or the adsorptive sheet according to 7. 9. An opening ratio of the fine holes is 3% to 10%.
The adsorptive sheet according to any one of claims 6 to 8, wherein 10. In addition to the granular activated carbon-containing sheet,
The adsorptive sheet according to any one of claims 1 to 9, further comprising a breathable sheet. 11. The adsorptive sheet according to claim 10, wherein the breathable sheet is laminated on a backside layer of the granular activated carbon-containing sheet. 12. The adsorptive sheet according to claim 10, wherein the breathable sheet mainly comprises a nonwoven fabric made of film split type electret fibers. 13. The adsorptive sheet according to claim 12, wherein the breathable sheet is further provided with a nonwoven fabric, woven or net cover factor. 14. The packing density of the air-permeable sheet is set to 0.1.
The adsorptive sheet according to any one of claims 10 to 13, which has a weight of 01 to 0.20 g / cc. 15. An air purification filter obtained by molding the adsorptive sheet according to claim 1 into a pleated or corrugated shape. 16. The filter has a thickness of 10 to 400 m.
The filter for air purification according to claim 15, wherein m and an interval between peaks are 2 to 30 mm. 17. A method for producing an adsorptive sheet having a step of forming a granular activated carbon-containing sheet, wherein the step of forming the granular activated carbon-containing sheet comprises an average particle diameter of 60 to 600 μm
Granulated activated carbon, supporting fibers, a step of preparing an aqueous slurry containing water-swellable adhesive fibers, a step of developing the aqueous slurry in a planar manner, mechanical dehydration and drying from the developed aqueous slurry And a process for producing an adsorptive sheet.