JP6099330B2 - filter - Google Patents

Description

  The present invention relates to a filter.

2. Description of the Related Art Conventionally, a filter having a characteristic that can hold a large amount of dust and the like in an object to be filtered and can suppress an increase in pressure loss due to dust collection is required.
In order to obtain a filter having such characteristics, for example, a nonwoven fabric, a woven fabric, a knitted fabric, or the like is employed as a member constituting the filter. The fabric is used as a filter alone or as a filter in a state of being laminated with a separately prepared fabric.

As an example of a filter employing a fabric, a composite nonwoven fabric disclosed in JP-A-10-86256 (Patent Document 1) is known.
The composite nonwoven fabric disclosed in Patent Document 1 includes a nonwoven fabric layer including fine fibers (3, 3 ′) formed by dividing the sectional composite fiber (1) having a cross-sectional shape illustrated in FIG. ing. The split conjugate fiber (1) is split into a branched fiber (2) and a fine fiber (3, 3 ′).

The invention of Patent Document 1 is an invention aiming to provide a composite nonwoven fabric having high bulkiness, flexibility and good texture, and the nonwoven fabric has bulkiness by including the branched fiber (2). It is disclosed that the nonwoven fabric exhibits a good texture by exerting and containing fine fibers (3, 3 ′). Moreover, in order to make the bulkiness of a nonwoven fabric still more favorable, it is disclosing that the said division | segmentation type | mold composite fiber (1) which is not divided | segmented needs to exist partially.

JP-A-10-86256 (Claims, 0005, 0025-0026, FIG. 5 etc.)

  However, since the nonwoven fabric which comprises the filter which concerns on patent document 1 contains the said fine fiber, it is densified. And since the porosity (space which can hold | maintain dust) becomes small as a nonwoven fabric becomes densified, it was thought that the amount of dust holding | maintenance of the composite nonwoven fabric provided with the said nonwoven fabric is small. Furthermore, since the non-woven fabric is likely to be clogged as it becomes denser, it was considered that the composite non-woven fabric provided with the non-woven fabric tends to increase in pressure loss as dust is collected.

Therefore, as long as a filter made of a composite nonwoven fabric according to Patent Document 1 is studied, there is a limit to providing a filter that can hold a large amount of dust and suppress an increase in pressure loss due to dust collection. It was considered.

An object of the present invention is to provide a filter capable of holding a large amount of dust and suppressing an increase in pressure loss due to dust collection.

The present invention
“A filter comprising a fabric,
Fibers constituting the fabric, the specific surface area is greater than 1.29m 2 / ^g, and is composed of only modified cross-section fiber projections of the Y-shaped from the center is out 4箇Tokoro突 in the fiber cross-section,
Moreover with comprising a pleated shape by laminating a fabric and a support pairs described above, it characterized <br/> that aforementioned fabric filtration upstream becomes present filter. "
It is.

The present invention is an invention relating to “a filter including a fabric”, wherein “the fibers constituting the fabric are only atypical cross-section fibers having a specific surface area larger than 1.29 m ² / g”, whereby the voids of the fabric It has been found that a filter can be provided that can increase the rate, and that can hold a large amount of dust and suppress an increase in pressure loss due to dust collection.

It is an electron micrograph of the fiber cross section of the atypical cross section fiber used in Example 1-2. It is an electron micrograph of the fiber cross section of the atypical cross section fiber used in Comparative Example 1-2. It is the cross-sectional shape of a split type composite fiber which patent document 1 discloses.

The fabric referred to in the present invention refers to, for example, a nonwoven fabric, a woven fabric, or a knitted fabric.
The fineness of the fibers constituting the fabric is not particularly limited, but the fineness is 1 to 1 so that a filter capable of holding a large amount of dust and suppressing an increase in pressure loss due to dust collection can be obtained. It is preferably 50 dtex, more preferably 1 to 30 dtex. Moreover, although fiber length is not specifically limited, It is preferable that it is 1 mm or more, and it is more preferable that it is 3-100 mm. In addition, depending on the manufacturing method of a fiber, it can also be a continuous fiber. Moreover, two or more types of fibers that differ in terms of fineness and / or fiber length may be included.

The present invention is characterized in that “the fibers constituting the fabric are only atypical cross-section fibers having a specific surface area greater than 1.29 m ² / g”.
The specific surface area as used herein refers to a value obtained by the measurement method described below.
A-1. In accordance with the measurement method described in JIS 1013: 2010 (8.3 fineness), the fineness (decitex) of the fibers constituting the fabric is measured.
A-2. From the obtained fineness, the mass per 1 m of fiber length (A, g / m) is calculated.
B-1. The cloth is cut in the thickness direction, or the fibers constituting the cloth are cut in the fiber diameter direction, and an electron micrograph of the fiber cross section of the fiber is taken.
B-2. From the obtained electron micrograph, 100 fibers showing the front of the fiber cross section are selected. And the shortest length (m) of the fiber outer periphery in the fiber cross section of each selected fiber is measured, and the average shortest length (m) is calculated | required by calculating the average value.
B-3. The average surface area (B, m ² / m) per 1 m of the fiber length of the fiber is obtained by adding the fiber length of 1 m to the determined average shortest length (m). Since the cross-sectional area of the fiber cross section is a very small value with respect to the average surface area, the cross-sectional area of the fiber cross section is treated as 0 when calculating the specific surface area.
C. The fibers constituting the fabric by substituting the mass per 1 m of fiber length (A, g / m) and the average surface area per 1 m of fiber length (B, m ² / m) into the following equation: The specific surface area (m ² / g) is calculated.
Specific surface area (m ² / g) = B (m ² / m) ÷ A (g / m)

Since the specific surface area of the atypical cross-section fibers constituting the fabric of the present invention is greater than 1.29 m ² / g, the present inventors have a large amount of dust retention and an increase in pressure loss due to dust collection. It has been found that a filter capable of suppressing the above can be obtained. Therefore, the specific surface area of the modified cross-section fiber is preferably as large as possible, preferably 1.5 m ² / g or more, and most preferably 2 m ² / g or more. In addition, although an upper limit is not limited, 10 m < ² > / g or less is realistic.

In addition, in the electron micrograph image | photographed by the (B-1) term of the measuring method of the specific surface area mentioned above with the atypical cross-section fiber as used in this invention, the shape of a fiber cross section (shape of fiber outer periphery) is other than round shape. It means that. The cross-sectional shape of the irregular cross-section fiber is not limited, but for example, a polygonal shape such as a triangular shape, an alphabetic character shape such as a Y shape, a symbolic shape such as an irregular shape, a multileaf shape, an asterisk shape, etc. Alternatively, the shape may be a combination of a plurality of these shapes.

Furthermore, the present inventors have found that the porosity of the fabric can be improved by adopting a modified cross-section fiber having three or more Y-shaped protrusions protruding from the central portion in the fiber cross section as the modified cross-section fiber.
The reason for this is not completely clear. However, in the modified cross-section fiber having the above-mentioned cross-sectional shape, a large void is formed between adjacent Y-shaped protrusions, so that a fabric having a wide porosity can be formed. it is conceivable that. And it is thought that while holding up the dust in the filter provided with the fabric, it is possible to increase the amount of dust and to suppress an increase in pressure loss due to dust collection.

In addition, when adopting an atypical cross-section fiber having three or more Y-shaped projections protruding from the central portion in the fiber cross section as the atypical cross-section fiber, the present inventors provide a fabric that is easy to pleat even when the thickness is thick. Found that can be obtained.
The reason for this is not completely clear, but in the modified cross-section fibers having the above-mentioned cross-sectional shape, the Y-shaped cross-section fibers having the cross-sectional shape adjacent to each other have one Y-shaped cross-section fiber. The shape-shaped protrusions are fitted and fixed in the gap formed between adjacent Y-shaped protrusions provided in the other atypical cross-section fiber, so that it is easy to pleat even when the thickness is thick. It is believed that the fabric can be constructed.
In particular, when the filter of the present invention includes a pleated fabric, it is easy to pleat even when the fabric is thick, so that the fabric present per area when the filter is viewed from the main surface side. This is preferable because the volume can be increased, and a filter that can hold a large amount of dust and suppress an increase in pressure loss due to dust collection can be obtained.

In order to exhibit the above-described effect more effectively, the fiber constituting the fabric of the present invention has a specific surface area greater than 1.29 m ² / g, and 3 Y-shaped protrusions from the center in the fiber cross section. It is preferable that only the atypical cross-section fibers protrude from the portion.

  The fiber component constituting the modified cross-section fiber is not limited and is appropriately selected. For example, a polyolefin resin (polyethylene, polypropylene, polymethylpentene, a part of hydrocarbon is substituted with a cyano group, fluorine, or chlorine). Such as polyolefin resins having a structure substituted with halogen, etc.), styrene resins, vinylon resins, polyether resins (polyether ether ketone, polyacetal, phenol resins, melamine resins, urea resins, epoxy resins, modified resins) Polyphenylene ether, aromatic polyether ketone, etc.), polyester resins (polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, Realylates, wholly aromatic polyester resins, unsaturated polyester resins, etc.), polyimide resins, polyamideimide resins, polyamide resins (eg, aromatic polyamide resins, aromatic polyetheramide resins, nylon resins, etc.), nitrile groups Resin (for example, polyacrylonitrile), urethane resin, epoxy resin, polysulfone resin (polysulfone, polyethersulfone, etc.), fluorine resin (polytetrafluoroethylene, polyvinylidene fluoride, etc.), cellulose resin, poly Benzimidazole resin, acrylic resin (for example, polyacrylonitrile resin copolymerized with acrylic acid ester or methacrylic acid ester, modacrylic copolymerized with acrylonitrile and vinyl chloride or vinylidene chloride) Resin, etc.) and the like.

The fiber component described above may be either a linear polymer compound or a branched polymer compound, and the polymer compound may be a block copolymer or a random copolymer. There are no particular limitations on the three-dimensional structure or the presence or absence of crystallinity of the compound. Furthermore, what mixed the some fiber component may be sufficient, and it does not specifically limit.

The atypical cross-section fiber may be a composite fiber composed of two or more kinds of fiber components. When the surface of the composite fiber contains a low melting point fiber component, the fibers can be fused and integrated with the low melting point fiber component while maintaining the fiber form. Examples of the cross-sectional form of the composite fiber include a core-sheath type (including an eccentric type), a sea-island type, a side-by-side type, an orange type, and a multilayer laminated type.

The production method of the irregular cross-section fiber is not limited. For example, dry spinning method, wet spinning method, direct spinning method (melt blow method, spun bond method, electrostatic spinning method, spinning stock solution and gas flow are discharged in parallel. And the like (for example, the method disclosed in Japanese Patent Application Laid-Open No. 2009-287138), a method of removing one or more kinds of resin components from the composite fiber, a method of beating the fiber to obtain a modified cross-section fiber, and the like. It can be obtained by a method.

  When the fabric is a woven fabric or a knitted fabric, it can be prepared by weaving or knitting the modified cross-section fibers prepared as described above.

Moreover, when the said fabric is a nonwoven fabric, as a preparation method of the fiber web which can manufacture a nonwoven fabric, a dry method, a wet method, a direct spinning method etc. can be used, for example.
In addition, not only manufacturing a nonwoven fabric using only one layer of the fiber web prepared by the above-described method, but also preparing a nonwoven fabric using a laminated fiber web in which two or more fiber webs having the same or different fiber composition are laminated. You may do it. Furthermore, the fiber web may be a parallel web, a cross web, a random web, or a criss cross web obtained by laminating a parallel web and a cross web, and is not particularly limited.

Next, the non-woven fabric is prepared by bonding the irregular cross-section fibers of the fiber web. Examples of the bonding method of the irregular cross-section fibers include a method of entanglement with a needle or a water flow, and melting and bonding low melting point fiber components. A method of bonding with a binder, or a method of using these in combination. In addition, as a method of melting the fiber component having a low melting point, for example, a method of heating and pressurizing with a calender roll, a method of heating with a hot air dryer, etc. can be used, and a base material having a relatively rough structure can be formed. Heating with a dryer is preferred.

In addition, the kind of binder which can be used in this invention can be adjusted suitably, and is not limited. As the binder, the same fiber component as that of the fabric described above can be used. In addition, as the binder, for example, a vinyl chloride component (for example, vinyl chloride copolymer resin), a vinylidene chloride component, a vinyl acetate component or ethylene can be used. A binder containing a component (for example, ethylene-vinyl acetate copolymer resin), a styrene component or a butadiene component (for example, styrene / butadiene-based latex), an acrylic ester component, a urethane component, or the like can be used.
In addition, a crosslinking agent (for example, melamine type, oxazoline type, isocyanate type, etc.) may be added to the binder, and other functional agents such as surfactants, oil repellents, penetrants, flame retardants, etc. May be added.
The state of the binder to be used can be, for example, an emulsion, latex, suspension, solution or the like, and is not particularly limited.

  The above-described fabric can be used alone as a filter, or a plurality of fabrics can be stacked and used as a filter. As a laminating method, a method of simply superimposing the fabrics, a method of laminating and integrating the fiber components constituting each fabric, a method of laminating and integrating the fabrics with a binder, etc. Can be adopted.

Further, the shape of the fabric prepared as described above can be appropriately adjusted and is not limited. For example, the fabric may be punched or cut into a square shape, a rectangular shape, a round shape, an oval shape, or the like. Further, for example, pleating may be performed. In particular, when the filter of the present invention includes a pleated fabric, the volume of the fabric existing per area when the filter is viewed from the main surface side can be increased, and the amount of dust retained is large. At the same time, it is preferable to be a filter that can suppress an increase in pressure loss accompanying dust collection.

  Furthermore, for example, when functionalities such as antibacterial properties, antiviral properties, antifungal properties, deodorizing properties, photocatalytic properties or flame retardancy are imparted to the fabric, for example, antibacterial agents, antiviral agents, antifungal agents, Functional materials such as deodorizers such as activated carbon, photocatalyst particles such as titanium oxide, or flame retardants such as phosphate flame retardants and aluminum hydroxide may be added to the fabric.

  The method of adding the above-described functional material to the fabric is appropriately adjusted. For example, a method of preparing a fabric using a modified cross-section fiber kneaded with the functional material, a molten thermoplastic resin derived from a hot melt nonwoven fabric is used. A method of adhering and supporting a functional material on the main surface of the fabric, and adhering the functional material to the main surface of the fabric via a molten thermoplastic resin in the form of dots, lines or spider webs applied to the fabric. A method in which the functional material heated from the main surface side of the fabric is brought into contact with the surface of the atypical cross-section fiber and a part of the functional material is buried in the surface (for example, a method disclosed in Japanese Patent Application Laid-Open No. 2004-3070) Etc.) can be employed.

In particular, when a method of adhering and supporting a functional material on the main surface of the fabric via a molten thermoplastic resin in the form of dots, lines or cobwebs applied to the fabric is adopted, the fabric in which the functional material is adhered The increase in the initial pressure loss is reduced, the area covered by the surface of the functional material with the thermoplastic resin can be reduced, the function of the functional material can be effectively exhibited, and the dust collection efficiency of the fabric can be reduced. The dust holding amount can be improved, which is preferable.

The fabric prepared as described above can be used as a filter as it is, but the handleability and strength are improved, or the increase in pressure retention due to dust retention and dust collection is suppressed. In order to improve the filter performance, a filter may be prepared by laminating and reinforcing a support such as a separately prepared fabric, film or foam.

As a method of laminating the fabric and the support, a method in which the fabric and the support are simply overlapped, a method in which the organic polymer constituting the fabric and / or the support is melted and laminated and integrated, and the fabric and the support are bonded to each other. For example, a method of adhering and stacking and integrating can be employed. In addition, when preparing a filter by laminating | stacking a cloth and a support body, it is preferable that the cloth exists in the filtration upstream in a filter. Since the fabric of the present invention having a high porosity is present on the upstream side of the filtration, the fabric acts as a pre-filter in the prepared filter, so that the amount of dust retained can be kept high, and the pressure loss associated with dust collection This is preferable because it is a filter that can suppress an increase in the temperature.

The basis weight or thickness of the filter prepared as described above is not particularly limited, and a filter capable of holding a large amount of dust and suppressing an increase in pressure loss due to dust collection is obtained. It adjusts so that it may be possible.
Basis weight of the filter, for example, is preferably from 40~750g / ^{m 2,} more preferably from 50 to 500 g / ^{m 2,} most preferably a 70~450g / ^{m 2.}
The thickness of the filter is preferably 300 μm to 3 mm, for example, and most preferably 350 μm to 2 mm. In addition, "thickness" as used in the field of this invention is 5 points | pieces when a 100-g load is applied to the thickness direction of the filter measured with the high precision digital measuring machine (Lightmatic (VL-50A) Mitutoyo Corporation). The arithmetic average value of the thickness.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.

Example 1
A spunbond nonwoven fabric using only the spunbond atypical cross-section fiber (fineness: 18 dtex) having the cross-sectional shape shown in FIG. 1 (four Y-shaped protrusions projecting from the center of the fiber cross section) as the constituent fiber (Weight: 90 g / m ² , thickness: 493 μm) was prepared.
In addition, the average shortest length of the spunbond atypical cross-section fiber measured from the electron micrograph of the cross section in the thickness direction of the spunbond nonwoven fabric was 375 μm. Therefore, the specific surface area of the spunbond atypical cross-section fiber was 2.08 m ² / g.
After the surface of the above-mentioned spunbond nonwoven fabric is melted linearly using a heat sealer, the filter is filtered by hand pleating so that the straight melted portion becomes a portion where the pleat peaks are continuous. Prepared.

The number of pleats on one main surface side of the filter was 45, and the number of pleats on the other main surface side of the filter was 44. Moreover, the space | interval of the vertex of adjacent pleat mountains was 5 mm. At this time, the outer dimensions of the filter are 225.5 mm in the direction orthogonal to the direction in which the apexes of the pleats continue (the length in the horizontal direction), and the length in the direction parallel to the direction in which the apexes of the pleats continue. The length (length in the vertical direction) was 235.5 mm, and the thickness was 29 mm.

(Comparative Example 1)
A spunbond nonwoven fabric (weight per unit: 90 g / m ² , thickness: 457 μm) was prepared using only the spunbond atypical cross-section fiber (fineness: 14 dtex) whose cross-sectional shape shown in FIG. .
In addition, the average shortest length of the spunbond atypical cross-section fiber measured from the electron micrograph of the cross section in the thickness direction of the spunbond nonwoven fabric was 180 μm. Therefore, the specific surface area of the spunbond atypical cross-section fiber was 1.29 m ² / g.

The spunbonded nonwoven fabric thus prepared was pleated in the same manner as in Example 1 to prepare a filter having the same outer dimensions as in Example 1.

(Example 2)
Using only the same spunbond atypical cross-section fiber as in Example 1 as a constituent fiber, a spunbond nonwoven fabric A (weight per unit area: 40 g / m ² , thickness: 350 μm) was prepared.
Further, as a support, only a spunbond fiber (fineness: 6 dtex) having a round cross-sectional shape was used as a constituent fiber to prepare a spunbond nonwoven fabric B (weight per unit: 22 g / m ² , thickness: 120 μm).

On one main surface of the spunbond nonwoven fabric A thus prepared, 5 g / m ² of a molten thermoplastic polyolefin resin was applied in the form of dots.
Subsequently, activated carbon particles (particle size range: 0.25 to 0.50 mm, particle shape: crushed, average particle size: 30) to the main surface of the spunbond nonwoven fabric A while the thermoplastic polyolefin resin is in a molten state. ˜60 mesh, specific surface area by BET method: 1000 m ² / g, packing density: 0.50 g / cm ³ ) is sprayed at 130 g per 1 m ² , and molten thermoplastic polyolefin resin is interposed The activated carbon particles were supported on one main surface of the spunbond nonwoven fabric A.
Then, a hot melt nonwoven fabric (weight per unit: 10 g / m ² ) of a thermoplastic polyolefin resin is laminated in the molten state from the supported activated carbon particle side, and the spunbond nonwoven fabric B is laminated between the molten states and press treatment is performed. (Pressure: 4 kg / cm ² , Time: 2 seconds) By providing a layer of activated carbon particles between the spunbond nonwoven fabric A and the spunbond nonwoven fabric B (weight per unit: 207 g / m ² , Thickness: 850 μm) was prepared.

After the surface of the above-mentioned spunbond nonwoven fabric is melted linearly using a heat sealer, the filter is filtered by hand pleating so that the straight melted portion becomes a portion where the pleat peaks are continuous. Prepared.
The number of pleats on one main surface side of the filter was 37, and the number of pleats on the other main surface side of the filter was 36. Moreover, the space | interval of the vertex of adjacent pleat mountains was 6 mm. At this time, the outer dimensions of the filter are 225.5 mm in the direction orthogonal to the direction in which the apexes of the pleats continue (the length in the horizontal direction), and the length in the direction parallel to the direction in which the apexes of the pleats continue. The length (length in the vertical direction) was 235.5 mm, and the thickness was 29 mm.

(Comparative Example 2)
Only the spunbond atypical cross-section fiber as in Comparative Example 1 was used as a constituent fiber to prepare a spunbond nonwoven fabric C (weight per unit: 40 g / m ² , thickness: 290 μm).
And the spunbond nonwoven fabric laminate (weight per unit: 207 g / m ² , thickness: 760 μm) was the same as in Example 2 except that the prepared spunbond nonwoven fabric C was used instead of the spunbond A in Example 2. Was prepared.

Example: After the surface of the above-mentioned spunbond nonwoven fabric is linearly melt processed using a heat sealer, the portion melted in a straight line is pleated by hand so that the apex of the pleat mountain is continuous. A filter with the same outer dimensions as 2 was prepared.

Each filter of Example 1-2 and Comparative Example 1-2 prepared as described above was subjected to the measurement described below.

(Confirmation of pleating)
The easiness of pleating when the spunbond nonwoven fabric prepared in Example 1 and Comparative Example 1 and the spunbond nonwoven fabric laminate prepared in Example 2 and Comparative Example 2 were pleated by hand was compared.

(Measurement of filter performance)
Each filter of Example 1-2 and Comparative Example 1-2 was subjected to an ASHRAE standard 52. 1 standard air filter test device (wind speed: 2.7 m / sec, dust used: ASHRAE DUST).
In addition, a “passing dust collecting filter” that plays a role of collecting dust passing through the filter was provided on the downstream side of the site where the filter of the air filter test apparatus was provided. In addition, when the filters of Example 2 and Comparative Example 2 were used for measurement, they were installed so that the spunbond nonwoven fabric B side was directed to the passing dust collection filter side.

And the initial pressure loss (Pa) and the collection efficiency (%) in each filter of Example 1-2 and Comparative Example 1-2 were each measured with the above-mentioned air filter test apparatus. The collection efficiency (%) is the mass of dust (unit: g / m ² ) held by the filter when the pressure loss (Pa) value in the filter being measured reaches 200 Pa. And the total mass (unit: g / m ² , hereinafter referred to as DFC) of the dust supplied to the filter up to the time point is measured, and DHC (g / m ² ) in DFC (g / m ² ) is measured. ) To calculate the percentage.

The results subjected to the above measurements are summarized in (Table 1).

The filter of Example 1 was found to have a larger amount of dust retention (DHC) than the filter of Comparative Example 1 although the initial pressure loss and the average collection efficiency were equal.
And since the filter of Example 1 had much dust retention (DHC) which was able to be collected by the value of pressure loss rising to 200 Pa compared with the filter of Comparative Example 1, the filter of Example 1 is dust It was found that this filter can suppress the increase in pressure loss due to collection.
In addition, it was found that the spunbond nonwoven fabric prepared in Example 1 was easier to pleat like the spunbond nonwoven fabric prepared in Comparative Example 1 although it was thicker than the spunbond nonwoven fabric prepared in Comparative Example 1. .

The filter of Example 2 was found to have a larger amount of dust retention (DHC) than the filter of Comparative Example 2 although the initial pressure loss and the average collection efficiency were equal.
And since the filter of Example 2 had much dust holding amount (DHC) which was able to be collected by the value of pressure loss rising to 200 Pa compared with the filter of Comparative Example 2, the filter of Example 2 is dust It was found that this filter can suppress the increase in pressure loss due to collection.
The spunbond nonwoven fabric laminate prepared in Example 2 was pleated in the same manner as the spunbond nonwoven fabric laminate prepared in Comparative Example 2 although it was thicker than the spunbond nonwoven fabric laminate prepared in Comparative Example 2. It turns out that it is easy to do.

  The filter of the present invention is a filter that can hold a large amount of dust and suppress an increase in pressure loss due to dust collection. Therefore, the filter of the present invention can be used in, for example, a filter for a food or medical product production factory, a filter for a precision instrument manufacturing factory, a filter for indoor cultivation facilities for agricultural products, a filter for general households, or an office building. The filter can be used as a filter for a facility, a filter for an air purifier, a filter for an OA device, a filter provided in an electrical appliance, a cabin air filter, or the like.

Claims (1)

A filter comprising a fabric,
Fibers constituting the fabric is composed of only a modified cross-section fiber projections of the Y-shaped from the center of the specific surface area of greater than 1.29m 2 / ^g, and the fiber cross-section is out 4箇Tokoro突, moreover the together comprising a pleated shape by laminating a fabric and the support, you characterized in that the fabric is present in the filtered upstream filter.

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