JP2011072911A - Air cleaning filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter used for removing both components of gas and fine particles, having sufficiently high dust collecting amount and excellent flame retardancy. <P>SOLUTION: The air cleaning filter is formed by pleat-likely integrally molding a sheet containing an electret sheet formed by heat-adhesion of a reinforced net on at least one face of cloth, and holding a gas adsorbing layer containing activated carbon with the flameproofing cloth on the reinforced net face side of the electret sheet without substantially bonding. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air cleaning filter that is suitably used for filters for electronic devices such as copying machines, printers, computers, projectors, etc., in-vehicle filters, filters for home appliances such as air purifiers, and the like.

  In recent years, electronic devices such as copiers, printers, computers, projectors, and the like have been integrated and miniaturized, and heat is easily trapped inside the devices. In order to avoid this, exhaust heat by exhausting high-temperature air inside the equipment by a fan or the like has become indispensable. And various components included in the electronic device such as components used in printing such as ink and toner, plastic components constituting the main body of the electronic device, components included in rubber used in various joints, etc. The components are volatilized and become harmful gases such as gases and fine particles. When the hot air inside the equipment is discharged into the room, it is discharged into the room together. In recent years, due to increasing awareness of environmental issues, emission regulations have been implemented for the above harmful components, and in order to clear the regulations, a filter capable of removing both gas and particulate components is desired. . Moreover, since it installs in an electronic device, it is also desired that it is excellent in a flame retardance.

An air purification filter element in which a sheet-like electret filter and a sheet containing an adsorbent that adsorbs malodors are laminated and integrally formed into a pleat shape is disclosed as a filter for the purpose of removing both components of gas and fine particles. (For example, Patent Document 1).
However, since the interlayer between the electret filter and the sheet containing the adsorbent that adsorbs malodor is bonded with a hot melt adhesive, the gap between the layers is not sufficient, and a sufficiently high dust collection amount cannot be obtained. There's a problem. Also, the flame retardancy was not sufficient.

Furthermore, the flame retardant material is used for the reinforcing material sheet and the adsorptive sheet to increase the flame retardancy, and the adsorbing sheet is placed on the electret filter side of the sheet in which the sheet-like electret filter and the reinforcing material sheet are laminated. An air cleaning filter sheet in which a conductive sheet is laminated is disclosed (for example, Patent Document 2).
However, an adsorbent sheet is laminated on the electret filter side of the sheet in which the electret filter and the reinforcing material sheet are laminated, and the gap between the layers is not sufficient because it is bonded with a hot melt adhesive at the time of lamination. There was a problem that the amount of collected dust was not sufficient.

Also disclosed is an air filter device for a passenger compartment in which a filter layer including a nonwoven web of electret-charged thermoplastic microfibers and a gas adsorption layer including an adsorbent particle packed layer are co-pleated and are not substantially bonded. (For example, Patent Document 3).
However, since the filter layer does not contain a reinforcing material, the gap between the filter layer and the gas adsorbing layer is not sufficient, and as a result, there is a problem that a sufficiently high dust collection amount cannot be obtained.

  As mentioned above, it has a sufficiently high dust collection amount for filters installed inside electronic devices such as copiers, printers, computers, projectors, etc. and used for the purpose of removing both gas and particulate components, And the present condition is that the filter excellent in the flame retardance is not found.

JP-A-4-74505 JP-A-8-281030 Special table 2008-531280

  The present invention was devised to solve such problems of the prior art, and is installed inside electronic devices such as copiers, printers, computers, projectors, etc., for the purpose of removing both components of gas and fine particles. An object of the present invention is to provide an air cleaning filter having a sufficiently high dust collection amount and excellent in flame retardancy with respect to the filter used.

As a result of intensive studies in order to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention is as follows.
1. A sheet obtained by electretizing a sheet in which a reinforcing net is thermally bonded to at least one side of the fabric, and a deodorizing sheet in which a gas adsorbing layer containing activated carbon is sandwiched between flame retardant fabrics on the reinforcing net surface side of the electret sheet. An air cleaning filter obtained by pleating a filter material having a structure in which the reinforcing net is laminated, and the reinforcing net is thermally bonded between the reinforcing net and the deodorizing sheet laminated on the reinforcing net surface. An air cleaning filter, wherein a fabric and a deodorizing sheet laminated on the reinforcing net surface are not substantially bonded.
2. 2. The air cleaning filter according to 1 above, wherein an opening area of an air inflow portion of the reinforcing net is 50 to 99%.
3. 3. The air cleaning filter according to 1 or 2 above, wherein the reinforcing net has a thickness of 0.1 to 2 mm.

  An air cleaning filter according to the present invention includes a sheet obtained by electretizing a sheet having a reinforcing net thermally bonded to at least one surface of a fabric, and a gas adsorbing layer containing activated carbon on the reinforcing net surface side of the electret sheet. Since it is a filter material having a structure in which deodorizing sheets sandwiched between flame retardant fabrics are laminated, both components of gas and fine particles can be removed, and the flame retardancy is excellent. Furthermore, since the reinforcing net is interposed so as to provide a sufficient distance without bonding between the fabric of the electret sheet and the deodorizing sheet, the amount of collected dust is extremely high.

Hereinafter, the air cleaning filter of the present invention will be described in detail.
The air cleaning filter of the present invention contains an electret sheet in which a reinforcing net is thermally bonded to at least one side of a fabric, and a gas adsorbing layer containing activated carbon is made flame-retardant on the reinforcing net surface side of the electret sheet. The deodorizing sheet sandwiched between the fabrics is between the reinforcing net and the deodorizing sheet laminated on the reinforcing net surface, and between the fabric thermally bonded to the reinforcing net and the deodorizing sheet laminated on the reinforcing net surface. It is preferable that the filter is integrally formed into a pleat shape after being laminated without substantially adhering. By including a sheet in which a reinforcing net is thermally bonded to at least one surface of the fabric, workability during pleating is improved. Further, since the sheet is electretized, high dust collection efficiency can be realized. If a sheet having a reinforcing net thermally bonded to at least one side of the fabric is not included, the processability during pleating processing is deteriorated, and if the sheet is not electretized, the dust collection efficiency is lowered. .

  Further, on the reinforcing net surface side of the electret sheet, a deodorizing sheet in which a gas adsorption layer containing activated carbon is sandwiched between flame retardant fabrics, between the reinforcing net and the deodorizing sheet laminated on the reinforcing net surface, and the above By laminating the fabric with the reinforcing net thermally bonded and the deodorizing sheet laminated on the reinforcing net surface without substantially bonding, a large gap is created between the sheets, and as a result, the amount of collected dust is reduced. The inventor has found that it is higher. If the deodorizing sheet is not on the reinforcing net surface side of the electret sheet, the reinforcing net does not serve as a spacer between the sheets, so the amount of dust collected is low. Moreover, when the electret sheet | seat and the deodorizing sheet | seat are laminated | stacked by adhesion | attachment, the gap | interval between sheets becomes small and the problem that a sufficiently high dust collection amount cannot be obtained arises. Here, being substantially not bonded means not being bonded in a portion excluding the peripheral portion of the filter.

  The fabric used for the dust filter of the present invention serves as a filter, and for example, a nonwoven fabric, a woven fabric, a knitted fabric or the like can be used. From the viewpoint of cost, it is preferable to use a nonwoven fabric. As the material of the fabric, general polymer materials such as polyethylene, polypropylene, and polyester can be used. From the viewpoint of cost, strength, and electretization, it is preferable to use a polypropylene nonwoven fabric.

It is preferable that the fabric weight is 5 to 100 g / m ² . Most preferably, it is 10-50 g / m < ² >. If the basis weight is less than the above range, the strength of the fabric becomes weak, and problems such as tearing may occur during pleating. On the other hand, if the above range is exceeded, there may be a problem that workability at the time of pleating deteriorates.

The thickness of the fabric is preferably 0.01 to 2 mm. Especially preferably, it is 0.03-1 mm. If the thickness is less than the above range, similarly, the strength of the fabric becomes weak and problems such as tearing may occur during pleating. On the other hand, if the above range is exceeded, there may be a problem that workability at the time of pleating deteriorates. Here, the thickness is a thickness when a load of 7 g / cm ² is applied to the fabric.

  The average fiber diameter of the fibers constituting the fabric is preferably 1 to 300 μm. More preferably, it is 10-100 micrometers. If the average fiber diameter is less than the above range, similarly, the strength of the fiber becomes weak and problems such as tearing may occur during pleating. Further, if the above range is exceeded, there may be a problem that workability at the time of pleating deteriorates.

  The reinforcing net used in the dust filter of the present invention is for imparting rigidity to the fabric, improving shape retention and pleatability, and increasing the amount of dust collected by creating a gap between the fabrics. It is.

  The reinforcing net needs to have an opening area ratio of 50 to 99% of the air inflow portion from the fabric to be thermally bonded. Preferably it is 70 to 97%. When the opening area ratio is less than the above range, there is a problem that the effective filtration area decreases and the pressure loss increases. On the other hand, if the above range is exceeded, sufficient rigidity cannot be imparted to the filter, which may cause a problem in shape retention.

The thickness of the reinforcing net is preferably 0.01 to 2 mm. More preferably, it is 0.03 to 1 mm. If thickness is less than the said range, the space | interval between fabrics becomes small and the problem that a sufficiently high dust collection amount cannot be obtained may arise. On the other hand, if the above range is exceeded, there may be a problem that workability at the time of pleating deteriorates. Here, the thickness is a thickness when a load of 7 g / cm ² is applied to the reinforcing net.

Basis weight of the reinforcing net is preferably 10 to 100 g / m ^2. Most preferably, it is 20-50 g / m < ² >. If the basis weight is less than the above range, the gap between the fabrics becomes small, and a problem that a sufficiently high dust collection amount cannot be obtained may occur. On the other hand, if the above range is exceeded, there may be a problem that workability at the time of pleating deteriorates.

  The reinforcing net is thermally bonded to the fabric, but is preferably made of a thermoadhesive synthetic resin so that it can be thermally bonded by itself. In this case, from the viewpoint of workability, a material having a melting point as low as possible is preferable. For example, polyethylene, polypropylene, or a copolymer thereof is preferably used. If the reinforcing net itself does not have thermal adhesion, it is bonded to the fabric with a thermal adhesive.

  The electret sheet in which the reinforcing net is thermally bonded to at least one surface of the fabric of the present invention may be obtained by electretizing by a known method after the fabric and the reinforcing net are thermally bonded and laminated, or electretized by a known method. You may obtain by laminating | stacking a fabric and a reinforcement net | network. In addition, you may use the electret sheet | seat which heat-bonded the reinforcement net | network to both surfaces of the fabric.

  The deodorizing sheet in the present invention preferably has a structure in which a gas adsorption layer containing activated carbon is sandwiched between flame retardant fabrics. With such a laminated structure, falling off of the activated carbon particles can be reduced during normal use. Although the flame retardant fabric to be used is not particularly limited, for example, a non-woven fabric, a knitted fabric, or a fabric obtained by making flame retardant can be used. From the viewpoint of preventing the activated carbon from falling off, those having a particle size smaller than the particle size of the activated carbon are preferable.

  As the nonwoven fabric, for example, it can be made from rayon fiber, polypropylene fiber, aramid fiber, glass fiber, cellulose fiber, nylon fiber, vinylon fiber, polyester fiber, polyolefin fiber, and polyester from the viewpoint of production cost and availability. It is preferably made of fiber or polyolefin fiber. Moreover, as a manufacturing method of a nonwoven fabric, a dry method, a spun bond method, a melt blow method, a thermal bond method, a chemical bond method, a needle punch method, a spun lace method (water flow entanglement method) and the like can be used.

  A general technique can be used as a technique for making the fabric flame-retardant. For example, a method of attaching a flame retardant to a fabric, a method of kneading a flame retardant into a constituent fiber of the fabric, or the like can be used. The flame retardant to be used is not particularly limited, but phosphorus-based flame retardants such as aluminum phosphate, condensed phosphate amide and melamine polyphosphate, nitrogen-based flame retardants such as melamine cyanurate, metal hydroxides such as aluminum hydroxide, etc. Can be used. Among these, a phosphorus-based flame retardant is preferable from the viewpoint of flame retardant effect.

The basis weight and thickness of the flame retardant fabric in the present invention are not particularly limited, but the basis weight is preferably 10 g / m ^{2 to} 100 g / m ² and the thickness is preferably 0.05 mm to 3 mm. When the basis weight is less than 10 g / m ² , the activated carbon falls off from the fabric during the production of the deodorizing sheet, and when it exceeds 100 g / m ² , the workability deteriorates. Moreover, when thickness exceeds 3 mm, the handleability at the time of activated carbon layer formation may worsen. Here, the thickness of the fabric refers to the thickness measured at a load of 7 g / cm ² .

Flame retardant quantity which is contained in the flame retardant fabric of the present invention is preferably ^{5g / m 2 ~50g / m 2} . If it is less than 5 g / m ² , sufficient flame retardancy cannot be obtained. If it exceeds 50 g / m ² , the amount of the flame retardant is too large, and the flame retardant falls off, resulting in poor processability.

The activated carbon in the present invention is not particularly limited as long as harmful gas components can be removed. For example, coal-based activated carbon, coconut shell-based activated carbon, wood-based activated carbon, or the like can be used. The specific surface area of the activated carbon particles preferably 500 g / m ² or more, more preferably from 800~2500g / m ^2. When the specific surface area is less than 500 g / m ² , the gas removal performance is lowered.

  The average particle diameter of the activated carbon in the present invention is not particularly limited, but is preferably 50 to 800 μm. When the average particle diameter is less than 50 μm, dust and the like are generated, so that the handleability is deteriorated, and when it exceeds 800 μm, formation of the activated carbon layer may be difficult.

The content of activated carbon in the present invention is preferably 50 to 500 g / m ² . More preferably, it is 70-400 g / m < ² >. If the content of activated carbon is less than the above range, the performance of removing harmful gases such as toluene is low, and if it exceeds the above range, the handleability during the formation of the gas adsorption layer may be deteriorated.

  Although it does not specifically limit regarding components other than activated carbon contained in the gas adsorption layer of this invention, It is preferable that a thermoplastic resin binder particle is contained. The thermoplastic resin binder particles have a role of adhering each component contained in the gas adsorption layer to prevent the activated carbon from falling off during normal use and to improve the handleability when forming the gas adsorption layer. For example, known thermoplastic resins such as polyolefin resins (polyethylene resins, polypropylene resins, etc.), polyester resins, polystyrene resins, polyvinyl acetate, urea resins, acrylic resins, and the like can be used. Among these resins, polyolefin resins and polyester resins are preferable from the viewpoint of cost and availability.

  The average particle diameter of the thermoplastic resin binder particles is not particularly limited, but is preferably 1.0 to 100 μm. More preferably, it is 5.0-50 micrometers. When the average particle diameter is less than the above range, dust and the like are generated, so that the handleability is deteriorated. When the average particle diameter exceeds the above range, there is a possibility that the activated carbon is not uniformly mixed with the activated carbon.

  The content of the thermoplastic resin binder particles in the gas adsorption layer is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the activated carbon particles. More preferably, it is 5 to 30 parts by weight. When the content of the thermoplastic resin binder particles is less than the above range, the activated carbon layer is weakly fixed and the handleability is poor, and when the content exceeds the above range, the thermoplastic resin binder acts as a combustion product at the time of combustion. I can't get sex.

  Moreover, it does not specifically limit regarding components other than activated carbon and a thermoplastic resin binder contained in the gas adsorption layer of this invention. In order to enhance the flame retardancy of the air cleaning filter, it is preferable to contain a flame retardant in the gas adsorption layer. Although the flame retardant used is not particularly limited, a phosphorus flame retardant such as aluminum phosphate, condensed phosphoric acid amide, and melamine polyphosphate, a nitrogen flame retardant such as melamine cyanurate, and a metal hydroxide such as aluminum hydroxide Etc. can be used. Among these, a phosphorus-based flame retardant is preferable from the viewpoint of flame retardant effect. Although the average particle diameter of a flame retardant is not specifically limited, It is preferable that it is 1.0-100 micrometers. More preferably, it is 1.0-50 micrometers. If the average particle diameter is less than the above range, dusts and the like are generated, so that the handleability is deteriorated. If the average particle diameter exceeds the above range, there is a possibility that the activated carbon is not uniformly mixed with the activated carbon. The flame retardant content in the gas adsorption layer is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the activated carbon particles. More preferably, it is 3 to 20 parts by weight. If the content of the flame retardant is small, the effect of the flame retardant cannot be sufficiently exhibited, and if it is too large, the handleability at the time of forming the activated carbon layer may be deteriorated.

  The greatest characteristic of the air cleaning filter of the present invention is that a deodorizing sheet laminated between a reinforcing net and a deodorizing sheet laminated on the surface of the reinforcing net, and a fabric on which the reinforcing net is thermally bonded and the deodorizing sheet laminated on the surface of the reinforcing net. Between the two is substantially not bonded. Here, being not substantially bonded means not bonding at a portion excluding the peripheral portion of the filter, that is, at the air inflow portion.

  In the air cleaning filter of the present invention, the reason that the reinforcing net and the deodorizing sheet laminated on the reinforcing net surface are not substantially bonded is that when the filter material is pleated, the top of the pleat or The reason for this is to create a gap between the fabrics near the troughs, so that the fabric between the reinforcing net thermally bonded and the deodorizing sheet laminated on the reinforcing net surface is not substantially bonded. This is because a sufficient gap is generated between the fabrics of the air inflow portion. These gaps can greatly increase the amount of dust collected compared to the prior art.

  A general fold folding machine can be used for the pleating process in the present invention. For example, a reciprocating or rotary folding machine can be used.

  Hereinafter, the effects of the present invention will be described more specifically by way of examples. The following examples are not intended to limit the method of the present invention, and any design changes in accordance with the gist of the preceding and following descriptions are included in the technical scope of the present invention.

[Measurement method of dust collection amount]
A 150 x 150 mm size filter sample was loaded with JIS 15 type dust with a dust concentration of 0.5 g / m3 at a wind speed of 0.5 m / s, and the pressure loss [mmAq] before the dust load was measured. When the load is increased by 50 mmAq, the dust load is stopped. The amount of dust collected [g] when the dust load was stopped was measured.

[Measurement method of average fiber diameter]
Using a scanning electron microscope (manufactured by Hitachi, Ltd., S-3500), the diameters of the fibers constituting the fabric were measured at 100 points, and the results were arithmetically averaged to determine the average fiber diameter of the fabric.

[Flame retardancy test method]
Evaluation based on the UL94 test method defined by UL (UL94: Standard for Safety Tests for Flammability of Plastic Materials for Part of the 94th in Devices and Appliances. Horison. Horton. Then, determine the flammability grade from the flamed combustion time, flameless combustion time, combustion distance, and presence / absence of the absorbent cotton determined in the UL94 test method, and determine based on the determined criteria, and 94HF-1 or higher It was determined to pass.

[Method for producing flame retardant fabric]
Phoscon FR903N (manufactured by Meisei Chemical Co., Ltd.), a phosphorus-based flame retardant, is applied to a polyester spunlace nonwoven fabric (weighing 30 g / m ² , thickness 0.45 mm, average fiber diameter 20 μm) and dried, and the flame retardant is 15 g / m. ² Flame retardant fabric A attached was prepared.

[Production Method of Deodorizing Sheet A]
A mixture of 100 parts by weight of activated carbon (specific surface area of 1460 g / m ² , average particle diameter of 520 μm) and 10 parts by weight of thermoplastic resin binder particles (average particle diameter of 20 μm, polyethylene resin) is spread on the flame retardant fabric A. A gas adsorbing layer is formed, and the flame retardant fabric A is stacked on the gas adsorbing layer, and then sandwiched between iron plates heated to 140 ° C. and heat-pressed for 1 minute to obtain thermoplastic resin binder particles. The gas adsorbing layer was fixed by the above, and the deodorizing sheet A was produced. At this time, the amount of activated carbon contained in the deodorizing sheet was 142 g / m ² .

[Production Method of Deodorizing Sheet B]
On the flame retardant fabric A, 100 parts by weight of activated carbon (specific surface area 1460 g / m ² , average particle diameter 520 μm), 10 parts by weight of thermoplastic resin binder particles (average particle diameter 20 μm, polyethylene resin), phosphorus flame retardant (average) A gas adsorbing layer was formed by spraying a mixture of 5 parts by weight of a particle diameter of 10 μm and aluminum polyphosphate), and the flame retardant fabric A was stacked on the gas adsorbing layer, and then heated to 140 ° C. The deodorized sheet B was produced by sandwiching between iron plates and performing heat press for 1 minute to fix the gas adsorption layer with thermoplastic resin binder particles. At this time, the amount of activated carbon contained in the deodorizing sheet was 127 g / m ² .

[Production Method of Deodorizing Sheet C]
Polyester spunlace nonwoven fabric (weighing 30 g / m ² , thickness 0.45 mm, average fiber diameter 20 μm), activated carbon (specific surface area 1460 g / m ² , average particle diameter 520 μm) 100 parts by weight, thermoplastic resin binder particles (average A gas adsorbing layer is formed by spraying a mixture of 10 parts by weight of a particle diameter of 20 μm and polyethylene resin), a flame retardant fabric A is stacked on the gas adsorbing layer, and then heated to 140 ° C. The deodorized sheet C was prepared by fixing the gas adsorbing layer with the thermoplastic resin binder particles. At this time, the amount of activated carbon contained in the deodorizing sheet was 135 g / m ² .

<Example 1>
Polypropylene spunbonded nonwoven fabric (weighing 25 g / m ² , thickness 0.35 mm, average fiber diameter 20 μm) and polypropylene heat-bonding net (weighing 30 g / m ² , thickness 0.5 mm, opening area ratio of air inflow part 83%) After that, an electret sheet was produced by applying a DC voltage of 10 kV. The deodorizing sheet A is laminated without substantially adhering to the heat bonding net side, and a common pleat folder is used to perform co-pleating with a height of 20 mm and a pitch of 4 mm, and a 150 × 150 mm size filter sample is obtained. Created.

<Example 2>
Polypropylene spunbond nonwoven fabric (weighing 15 g / m ² , thickness 0.30 mm, average fiber diameter 30 μm) and polypropylene heat-bonding net (weighing 30 g / m ² , thickness 0.5 mm, opening area ratio of air inflow part 83%) After that, an electret sheet was produced by applying a DC voltage of 10 kV. The deodorizing sheet B is laminated without substantially adhering to the heat bonding net side, and a common pleat folder is used to carry out co-pleating with a height of 20 mm and a pitch of 4 mm, and a 150 × 150 mm size filter sample is obtained. Created.

<Comparative Example 1>
Polypropylene spunbonded nonwoven fabric (weighing 25 g / m ² , thickness 0.35 mm, average fiber diameter 20 μm) and polypropylene heat-bonding net (weighing 30 g / m ² , thickness 0.5 mm, opening area ratio of air inflow part 83%) After that, an electret sheet was produced by applying a DC voltage of 10 kV. The deodorizing sheet C is laminated on the heat bonding net side without substantially adhering, and a common pleat folder is used to perform co-pleating with a height of 20 mm and a pitch of 4 mm, and a 150 × 150 mm size filter sample is obtained. Created.

<Comparative Example 2>
Polypropylene spunbonded nonwoven fabric (weighing 25 g / m ² , thickness 0.35 mm, average fiber diameter 20 μm) and polypropylene heat-bonding net (weighing 30 g / m ² , thickness 0.5 mm, opening area ratio of air inflow part 83%) After that, an electret sheet was produced by applying a DC voltage of 10 kV. After deodorizing sheet A was laminated on the heat bonding net side, heat treatment was performed, and the electret sheet and deodorizing sheet A were heat bonded. Further, a common pleat folding machine was used, and co-pleating processing was performed at a peak height of 20 mm and a pitch of 4 mm to prepare a filter sample having a size of 150 × 150 mm.

<Comparative Example 3>
An electret sheet was prepared by applying a DC voltage of 10 kV to a polypropylene spunbonded nonwoven fabric (weighing 25 g / m ² , thickness 0.35 mm, average fiber diameter 20 μm). Further, the deodorizing sheet A is laminated without substantially adhering to the heat bonding net side, and a common pleat folding machine is used, and a co-pleating process is performed at a peak height of 20 mm and a pitch of 4 mm, and a 150 × 150 mm size filter A sample was created.

  About the sample obtained in Examples 1-2 and Comparative Examples 1-3, the spunbond nonwoven fabric side of the electret sheet | seat was made upstream, the amount of dust collection was measured, and the flame retardance test was implemented. The results are shown in Table 1. As is clear from Table 1, Examples 1-2 of the present invention are superior in flame retardancy as compared to the case where the gas adsorption layer in the deodorizing sheet is not sandwiched between flame retardant fabrics (Comparative Example 1). I understand that. Moreover, compared with the case where the layers between Examples 1 and 2 of the present invention and the fabric are thermally bonded (Comparative Example 2) and the electret sheet does not contain a reinforcing material (Comparative Example 3), It can be seen that the amount of collection is increasing.

  The air cleaning filter according to the present invention contains an electret sheet in which a reinforcing net is thermally bonded to at least one side of the fabric, and a gas adsorption layer containing activated carbon is made flame-retardant on the reinforcing net surface side of the electret sheet. Sheets sandwiched between fabrics are integrally formed into a pleat shape without substantially bonding, and electronic devices such as copiers, printers, computers, projectors, and homes such as in-vehicle filters and air purifiers. Can be used for dust filters used in electrical appliances.

Claims (3)

  A sheet obtained by electretizing a sheet in which a reinforcing net is thermally bonded to at least one side of the fabric, and a deodorizing sheet in which a gas adsorbing layer containing activated carbon is sandwiched between flame retardant fabrics on the reinforcing net surface side of the electret sheet An air cleaning filter obtained by pleating a filter material having a structure in which the reinforcing net is laminated, and the reinforcing net is thermally bonded between the reinforcing net and the deodorizing sheet laminated on the reinforcing net surface. An air cleaning filter, wherein a fabric and a deodorizing sheet laminated on the reinforcing net surface are not substantially bonded.   The air cleaning filter according to claim 1, wherein an opening area of an air inflow portion of the reinforcing net is 50 to 99%.   The air cleaning filter according to claim 1 or 2, wherein the reinforcing net has a thickness of 0.1 to 2 mm.