JP2002210316A - Filter bag medium and filter bag using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter bag medium capable of achieving the enhancement of dust collection efficiency, low pressure loss and the removal of a malodor or a harmful substance, and a filter bag using the same. SOLUTION: The filter bag medium comprises a sheetlike porous base material and a microporous layer wherein 10-300 pts.wt. of functional particles are mixed with 100 pts.wt. of a polar solvent soluble polymer is formed on the surface of the porous base material or embedded in the porous base material in the vicinity of the surface thereof and pores with a means pore size of 10 μm or less are formed in the microporous layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter filter in which a porous substrate such as a nonwoven fabric or a woven fabric is used by being sewn into a bag or an envelope in a bag filter which is one of dust collectors. More specifically, the present invention relates to a filter bug and a media thereof capable of not only capturing dust in the atmosphere but also adsorbing and removing odors and harmful substances.

[0002]

2. Description of the Related Art Bag filters are widely used as dust collectors attached to plants in various fields for the purpose of preventing pollution, improving the working environment, and collecting valuable powder. Dust collection in the bag filter is based on so-called surface filtration, which captures dust in a layer as close as possible to the surface of a porous substrate such as a nonwoven fabric or a woven fabric. Dust deposited on the surface layer is removed by a method such as vibration, back pressure, or pulse. As the material (media), a nonwoven fabric or woven fabric made of various synthetic fibers manufactured by needle punching, or a nonwoven fabric or woven fabric in which a resin layer having fine pores is laminated is used.

[0003]

From the viewpoint of responding to dust refinement and contributing to environmental protection, filter bugs include not only an improvement in dust trapping rate but also halogen compounds generated in a garbage incinerator. It is desired to adsorb, decompose and remove harmful substances. As a means for improving the dust capture rate, a porous substrate such as a nonwoven fabric or a woven fabric made of fine fibers is used as a filter bag medium. However, there is a limit to reducing the fiber diameter, particularly to producing fibers on the order of microns, and as a result, there is a limit to reducing the gap between the porous substrates. Therefore, if the dust to be captured is too small, it will leak from the gap between the porous substrates, making it difficult to improve the capture rate. In addition, there is a disadvantage that dust permeates into the porous substrate and surface filtration is hardly achieved.

On the other hand, when a conventional porous substrate having a resin layer having fine pores laminated thereon is used, it is easy to achieve surface filtration and the dust capture rate is improved. Since it does not have the function of adsorption or decomposition like a porous substrate, it is difficult to remove odors and harmful substances.

[0005] In view of such disadvantages of the prior art, the present invention provides
An object of the present invention is to provide a filter bag media capable of achieving an improvement in dust capture rate, low pressure loss, and removal of a bad smell and a harmful substance, and a filter bag using the same.

[0006]

According to a first aspect of the present invention, there is provided a filter bag medium comprising a sheet-like porous base material.
A microporous layer formed by mixing 10 to 300 parts by weight of functional particles with respect to 100 parts by weight of a polar solvent-soluble polymer is attached to a surface of a porous substrate and / or embedded near the surface; It has pores having an average pore diameter of 10 μm or less.

The mixing ratio of the functional particles is in the range of 50 to 200 parts by weight per 100 parts by weight of the polar solvent-soluble polymer, and the particle size of the functional particles is preferably 1 μm or less.

As the functional particles, one or more selected from the group consisting of porous materials having pores, clay compounds, materials having catalytic activity, and hydrophobic silica can be used. Item 3).

[0009] The microporous layer may be such that the skin layer on the surface is deleted.

[0010] The filter bag of the present invention uses any one of the above filter bag media (claim 5).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The filter bag media of the present invention comprises a polar solvent-soluble polymer and functional particles, and has fine pores having an average pore diameter of 10 μm or less in order to solve the above-mentioned problems in the conventional filter bag. The porous layer is provided on the surface of the porous substrate and / or embedded at least in the vicinity of the surface.

That is, the present inventor has found that the pores in the microporous layer comprising the polar solvent-soluble polymer and the functional particles are not only very small as compared with the pores of the conventional porous base material, but also the functional particles have a small size. The inventors focused on the fact that they have the inherent functions of adsorption and decomposition, and that the pores of the microporous layer have a pore structure consisting of gaps between particles and / or polymers. By attaching such a microporous layer to the surface of the porous substrate and / or burying it in the vicinity of the surface, it is possible to promote surface filtration and to remove odors and harmful substances.

From such a viewpoint, as a result of intensive studies on filter bag media capable of improving dust trapping performance, suppressing pressure loss, and further removing odors and harmful substances,
The present inventors have found that the above object can be achieved by attaching a microporous layer in which functional particles are mixed with a polar solvent-soluble polymer to a surface of a porous substrate and / or burying the microporous layer near the surface. Was completed.

The functional particles used in the present invention have a function of adsorbing and decomposing a odor-causing substance and various harmful substances. Examples thereof include activated carbon, zeolite, crystalline aluminophosphate type molecular sieve, and silica gel. ,silica,
Porous inorganic particles having micropores in particles such as diatomaceous earth, palygoskite, and sepiolite; clay compounds such as montmorillonite, bentonite, smectite, vermiculite, and kanemite; particles having catalytic activity such as titanium oxide and manganese oxide; Hydrophobized silica; those having a particulate morphology including short whisker whiskers such as aluminum hydroxide and magnesium hydroxide.

The particle size of these functional particles is not particularly limited, but is usually on the order of 10 ⁻² to 10 ¹ μm.
About 300 mesh pass with Tyler mesh (about 44m
μ) or less, and particularly preferably 1 μm or less.

The polar solvent-soluble polymer used in the present invention is a polymer soluble in a polar solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, dioxane, N-methylpyrrolidone. If it is not particularly limited, for example, polyurethane, polyacrylate, acrylic such as polyacrylonitrile, polyvinyl chloride, polyvinyl acetate, vinyl such as polyvinyl fluoride, epoxy, polysulfone, polyethersulfone , Phenolic, polystyrene, polyamide, polyester, styrene-butadiene copolymer,
Acrylonitrile-butadiene copolymers, their fluorine, silicone derivatives and the like are used.

In the present invention, other additives can be used as needed. Examples include inorganic fibers such as short fiber slag fibers, ceramic fibers, glass fibers, carbon fibers, activated carbon fibers, and metal fibers, silicones, fluorocarbons, long-chain fatty acid salts, and long-chain amine salts. And / or an oil repellent or a surfactant.

The mixing ratio of the polar solvent-soluble polymer and the functional particles is such that the polar solvent-soluble polymer 100
The functional particles are preferably 10 to 300 parts by weight, more preferably 50 to 200 parts by weight, based on parts by weight. If the amount is less than 10 parts by weight, the content of the functional particles is too small, and the removal rate of harmful substances decreases. If the amount is more than 300 parts by weight, it becomes difficult to fix the functional particles to the porous base material, The functional particles can easily fall off at the time of wiping.

The pore size of the microporous layer comprising the polar solvent-soluble polymer and the functional particles is determined by the SEM
The image is image-analyzed, binarized, and expressed as a number average value of values calculated as a circle equivalent diameter (this value is referred to as “average pore diameter” in this specification), and the value is expressed as It is preferably 10 μm or less. If it exceeds 10 μm, the capture of fine dust becomes insufficient and surface filtration becomes difficult.

As the porous substrate on which the microporous layer is attached or embedded, for example, non-woven fabrics and woven fabrics made of various fibers such as polyester, aramid, polyphenylene sulfide, fluorine, glass and ceramic can be used. It is not something to be done. Also, the thickness of the porous substrate,
The basis weight, the type and the shape of the fiber are not particularly limited.

As a method for producing the filter bag media of the present invention by attaching or embedding the microporous layer in a porous substrate, a method such as direct coating, impregnation, or lamination is appropriately used.

For example, in the case of direct coating,
After coating and / or impregnating a mixed slurry of a polar solvent-soluble polymer and functional particles on a porous substrate, forming a microporous layer by wet coagulation or evaporation of the solvent to an external atmosphere, and then drying. Good. In the case of lamination, the slurry is coated on a non-porous base material such as a polyester film, and a film is formed by wet coagulation or evaporation of a solvent to an external atmosphere, followed by drying and peeling of the coating layer. To obtain a microporous membrane alone. The target substance can be obtained by laminating the obtained film on a porous substrate by a gravure method or the like and by integrating them.

The amount of the mixture of the polar solvent-soluble polymer and the functional particles on the porous substrate (attached or embedded amount) is preferably 5 to 500 g / m ² in terms of solid content. If it is less than 5 g / m ² , the fine porous layer is too thin to sufficiently capture fine dust, and the functions such as the removal of harmful substances are insufficient. On the other hand, if it exceeds 500 g / m ² , the air permeability becomes poor and the filtration rate cannot be increased.

In general, the pores formed by the wet coagulation method have macropores. However, if the particle size of the functional particles is 1 μm or less, it is difficult to form macropores, and it is possible to make small pores and uniform the pore distribution. And the surface filtration of fine dust is promoted.

[0025] In the wet coagulation method, a skin layer having pores smaller than other portions is easily formed on the surface of the obtained microporous layer (membrane). However, when it is necessary to increase the filtration speed of the filter bag, For example, using means such as polishing,
What is necessary is just to delete this skin layer.

In the filter bag media of the present invention obtained as described above, the pores in the microporous layer composed of the polar solvent-soluble polymer and the functional particles are fine gaps between the particles and / or the polymer, so Is significantly smaller than the pores of the porous substrate alone. Therefore, by using this microporous layer, the dust trapping efficiency can be greatly improved as compared with the related art.

Further, the macroporous layer of the porous substrate and the microporous layer of the microporous layer are formed by unevenly distributing the microporous layer on or near the surface of the porous substrate. The arrangement of the microporous layer on the side facilitates surface filtration, so that the dust layer deposited on the surface can be easily wiped off.

Further, since the fine porous layer contains functional particles capable of adsorbing and decomposing organic substances, not only the trapping rate is improved and low pressure loss is obtained, but also odor and harmful substances are eliminated. Removal is also possible.

The trapping of particles in a conventional filter bag has been filtration through a primary particle layer on which dust is deposited. Therefore, when a new bug is used, there is a problem in that blowing and clogging may occur unless the filter is operated at a lower filtration speed than in a normal operation in order to form a primary particle layer. That is, conventionally a break-in operation was required, but in the filter bag of the present invention, the fine porous layer composed of the functional particles and the polymer has a function of capturing dust similarly to the primary particle layer of the conventional bag. Therefore, the running-in operation can be omitted.

In the conventional bug, the trapping rate was reduced due to the drop of the primary particle layer. In the present invention, however, the functional particles were formed of a porous base material by a polymer acting as a binder. Since it is fixed to the surface or in the vicinity of the surface, the capture rate can be stabilized.

Further, when a porous material is used as the functional particles, the moisture contained in the exhaust gas is adsorbed, so that the absorbed dust is more easily separated.

[0032]

[Example 1] N, N-dimethylformamide
Polyurethane dissolved in water and 300 mesh pass activity
Charcoal particles, the latter with respect to 100 parts by weight of the former in solid content ratio
100 parts by weight to prepare a mixed slurry
Was. 500 g / m of this mixed slurry ²Needle
Polyester fiber (2 denier) obtained by punching method
50 g / m in solid content on non-woven fabric made of²Ko
Coating, wet coagulation, drying, filter bag
Got media.

Example 2 Polyethersulfone dissolved in N, N-dimethylformamide and activated carbon particles of 300 mesh pass were mixed at a solid content ratio of 100 parts by weight of the former to 30 parts by weight of the latter. Thus, a mixed slurry was prepared. The polyphenylene sulfide fibers obtained mixture slurry by a needle punching method of basis weight 500g / ^{m 2} (3 denier, 51 mm) manufactured by 100 g / ^{m 2} coated with solids nonwoven, after wet coagulation, drying, filter bugs media I got

Example 3 Polyurethane dissolved in N, N-dimethylformamide, hydrophobic silica having a particle diameter of 1 μm or less, and activated carbon particles having a mesh size of 300 were mixed with 100 parts by weight of polyurethane at a solid content ratio of 100 parts by weight. A mixed slurry was prepared by mixing 25 parts by weight of reactive silica and 25 parts by weight of activated carbon particles. The mixed slurry is weighed 500
g / m aramid fibers (2 denier, 76 mm) obtained by the ^second needle punching process made to 300 g / m ² coated with solids nonwoven, after wet coagulation, drying, it is removed by polishing the surface of the skin layer Got a filter bug media.

Comparative Example A nonwoven fabric made of the same polyester fiber (2 denier, 76 mm) having a basis weight of 500 g / m ² obtained by the needle punching method as in Example 1 was filtered without coating the mixed slurry. Media.

The dust trapping rate, pressure loss, and deodorizing rate of the filter bag media of the above Examples and Comparative Examples were measured under the following conditions. Table 1 shows the results.

[0037]

[Table 1]

[Capture rate and pressure loss] JIS B992
According to No. 1, the capture rate and pressure loss of 1 μm dust at a wind speed of 3 m / min were measured.

[Deodorization rate] Toluene concentration is 300 ppm
The filter bag media of the example and the comparative example cut into a circle having a diameter of 9 cm were individually sealed in a 1000 cc container adjusted to be as follows. Next, the toluene concentration in the container before and 1 hour after the sample was sealed was measured with a detector tube, and the deodorization rate was calculated by the following equation.

[0040]

(Equation 1)

As is evident from Table 1, the filter bag media of the present invention was excellent in the particle capture rate and had a deodorizing effect.

[0042]

As described above, the filter bag media of the present invention has a microporous layer comprising a polar solvent-soluble polymer and functional particles attached to the surface of a porous substrate and / or embedded near the surface. Structure. Therefore, in the filter bag using the same, the microporous layer having micropores is unevenly distributed on the surface layer, whereby the surface filtration is promoted and the dust capturing rate is improved. Then, the conventional adhesion layer is not required, the running-in operation can be omitted, and the dust accumulated on the surface can be easily wiped off.

Further, the functional particle layer in the microporous layer is fixed to the surface of the porous substrate by a polymer, and does not fall off by a wiping operation like a conventional primary particle layer. Can be stabilized.

As described in the second aspect, when the particle size of the functional particles is 1 μm or less, it is generally difficult to form macropores which are easily generated in the wet coagulation method, and it is possible to make small pores and uniform the pore distribution. And surface filtration of fine dust is promoted.

Further, by using the functional particles as described in claim 3, the function of adsorption and decomposition is added to the microporous layer, so that it is possible to remove odors and harmful substances.

Further, by removing the skin layer on the surface as described in claim 4, it is possible to increase the filtration speed of the filter bag.

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Claims (5)

[Claims] 1. A filter bag medium comprising a sheet-like porous base material, wherein a fine porous layer comprising 10 to 300 parts by weight of functional particles mixed with 100 parts by weight of a polar solvent-soluble polymer comprises a porous substrate. A filter bag medium which is provided on the surface of a material and / or is embedded near the surface, and has pores having an average pore diameter of 10 μm or less in the microporous layer. 2. The method according to claim 1, wherein the mixing ratio of the functional particles is in the range of 50 to 200 parts by weight per 100 parts by weight of the polar solvent-soluble polymer, and the particle size of the functional particles is 1 μm or less. The filter bag media according to 1. 3. The functional particles are one or more selected from the group consisting of porous materials having pores, clay compounds, materials having catalytic activity, and hydrophobic silica. The filter bag media according to claim 1, wherein 4. The filter bag media according to claim 1, wherein the skin layer on the surface of the microporous layer is removed. 5. A filter bag using the filter bag media according to claim 1.