JP2020081904A - Filter fabric for bag filter and manufacturing method for the same - Google Patents

Abstract

To provide a filter fabric for a bag filter that is excellent in collection performance, low in pressure loss and can suppress fall-out of fluffs, and further can prevent deterioration in dust collection performance caused by abrasion and cracking, and can desirably detect unevenness of mixed fiber, and a manufacturing method for the same.SOLUTION: A filter fabric for a bag filter is manufactured by laminating an unwoven fabric A including short fiber a with monofilament fineness of 0.3-0.9 dtex and short fiber b with monofilament fineness of 0.9-4.0 dtex, a base cloth and an unwoven fabric B including short fiber c with monofilament fineness of 0.3-4.0 dtex in this order.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a filter cloth for a bag filter, which is excellent in collection performance, has low pressure loss, can suppress fluff shedding, and is preferably capable of detecting mixed fiber spots, and a method for producing the same.

The bag filter is used, for example, by suspending it in a dust collecting chamber of the dust collector to collect dust. By repeatedly removing dust and collecting dust, it is possible to collect dust for a long time.

Conventionally, as such a bag filter, a woven fabric or a non-woven fabric (felt) entangled with a needle punch or the like has been used, but in recent years, from the viewpoint of downsizing of the device, a non-woven fabric with a large air permeability is used, A method of using a pulse jet to remove dust is becoming widespread. Furthermore, in order to collect, collect, and reuse fine dust, a filter using a fineness material or a filter of a type in which a PTFE membrane film is laminated is used (for example, see Patent Documents 1 and 2). ..

However, in the filter using the fineness material, the number of fibers constituting the fiber becomes large, so that the fluff easily falls off, the pressure loss (pressure loss) also increases, and the energy saving performance decreases. The filter of the type in which the PTFE membrane film is laminated has a problem that the dust collecting property and the life are shortened due to wear and cracks because of the thin layer.

JP, 9-313832, A JP, 10-230119, A

The present invention has been made in view of the above background, the object thereof is excellent in the collection performance is a low pressure loss, and can be suppressed fluff shedding, further dust collection deterioration due to wear and cracks less likely to occur. The present invention is to provide a filter cloth for bag filters capable of detecting mixed filaments, and a method for producing the same.

As a result of diligent studies to achieve the above-mentioned problems, the present inventors have found that in a filter cloth for a bag filter, by cleverly devising the fineness of the constituent fibers, the collection performance is excellent and the pressure loss is low, and It is possible to obtain a filter cloth for a bag filter that can suppress fluff shedding, further reduce deterioration of dust collecting property due to abrasion and cracks, and preferably find a filter cloth for a mixed fiber spot. Has been completed.

Thus, according to the present invention, "a non-woven fabric A including a short fiber a having a single fiber fineness of 0.3 to 0.9 dtex and a short fiber b having a single fiber fineness of 0.9 to 4.0 dtex, a base fabric, and a single fiber A filter cloth for a bag filter, characterized in that a non-woven fabric B containing short fibers c having a fiber fineness of 0.3 to 4.0 dtex is laminated in this order.”

At that time, the short fibers a and/or the short fibers b and/or the short fibers c are preferably dyeable fibers. Further, it is preferable that the short fibers a and/or the short fibers b and/or the short fibers c are aramid fibers that can be dyed. Further, it is preferable that all the fibers forming the filter cloth for the bag filter are meta-aramid fibers. In addition, the porosity is preferably in the range of 55 to 90%. Further, it is preferable that the non-woven fabric A is arranged on the filtration material collecting surface side.

Further, according to the present invention, in the method for producing a filter cloth for a bag filter described above, the non-woven fabric A, the base fabric and the non-woven fabric B are laminated in this order, needle punched, and then calendered. A method for manufacturing a filter cloth for a bag filter is provided.

According to the present invention, it is excellent in collection performance, has low pressure loss, and can suppress fluff shedding, and further, deterioration of dust collecting property due to wear and cracks is unlikely to occur, preferably for a bag filter capable of detecting mixed fiber spots. A filter cloth and a method for manufacturing the same are obtained.

Hereinafter, embodiments of the present invention will be described in detail. First, it is important that the single fiber fineness of the short fibers a is within a range of 0.3 to 0.9 dtex (more preferably 0.3 to 0.8 dtex, and particularly preferably 0.3 to 0.6 dtex). is there. When the single fiber fineness is less than 0.3 dtex, the strength of the fiber itself tends to be small, and the fiber is likely to be ruptured due to the entanglement treatment during the production of the filter cloth, which may reduce the strength of the nonwoven fabric, which is not preferable. Further, the pressure loss becomes large, which is not preferable. On the contrary, when the single fiber fineness is larger than 0.9 dtex, the dust collecting property is lowered and the dust easily enters the inside of the filter cloth, which is not preferable.

The short fiber a preferably has a tensile strength of 2.2 cN/dtex or more (more preferably 2.2 to 6.0 cN/dtex). When the tensile strength is less than 2.2 cN/dtex, the strength of the fiber itself tends to be small, and the fiber is likely to be ruptured due to entanglement treatment during the production of the filter cloth, which may reduce the strength of the nonwoven fabric.

The elongation of the short fiber a is preferably 25% or more (more preferably 25 to 50%). If the elongation is less than 25%, the fibers are likely to be broken by the entanglement treatment during the production of the filter cloth, and the strength of the nonwoven fabric may be reduced.

It is preferable that the short fibers a are crimped, because dust is easily collected. At that time, the number of crimps is preferably within a range of 1 to 30/2.54 cm. Moreover, it is preferable that the crimping ratio is within a range of 8 to 40%.

The short fiber a preferably has a fiber length within a range of 20 to 80 mm.
The fiber type of the short fiber a is not particularly limited, and examples thereof include polyester fiber, polyamide fiber, polyolefin fiber, PPS (polyphenylene sulfide) fiber, aramid fiber (wholly aromatic polyamide fiber), glass fiber and the like. Among them, meta-type aramid fiber (meta-type wholly aromatic polyamide fiber) is preferable in terms of heat resistance. Meta-type aramid fiber is a fiber made of a polymer in which 85 mol% or more of its repeating unit is m-phenylene isophthalamide. Such a meta-type wholly aromatic polyamide may be a copolymer containing the third component within the range of less than 15 mol%.

Such a meta-type wholly aromatic polyamide can be produced by a conventionally known interfacial polymerization method, and the polymer has a degree of polymerization of 0.5 g/100 ml of an N-methyl-2-pyrrolidone solution. Those having a measured intrinsic viscosity (IV) of 1.3 to 1.9 dl/g are preferably used. Examples of commercially available meta-aramid fibers include Conex (trademark), Conex Neo (trademark), Nomex (trademark) and the like.

On the other hand, it is important that the single fiber fineness of the short fibers b is within the range of 0.9 to 4.0 dtex (more preferably 1.0 to 3.2 dtex, and particularly preferably 1.2 to 2.5 dtex). is there. When the single fiber fineness is less than 0.9 dtex, the strength of the fiber itself tends to be small, and the fiber is likely to be ruptured due to the entanglement treatment during the production of the filter cloth, which may reduce the strength of the nonwoven fabric, which is not preferable. On the contrary, when the single fiber fineness is larger than 4.0 dtex, the dust collecting performance is deteriorated, which is not preferable. The single fiber fineness of the short fibers b is preferably larger than the single fiber fineness of the short fibers a.

In addition, the short fiber b preferably has a tensile strength of 2.2 cN/dtex or more (more preferably 2.2 to 6.0 cN/dtex). When the tensile strength is less than 2.2 cN/dtex, the strength of the fiber itself tends to be small, and the fiber is likely to be ruptured due to entanglement treatment during the production of the filter cloth, which may reduce the strength of the nonwoven fabric.

The short fiber b preferably has an elongation of 25% or more (more preferably 25 to 50%). If the elongation is less than 25%, the fibers are likely to be broken by the entanglement treatment during the production of the filter cloth, and the strength of the nonwoven fabric may be reduced.

It is preferable that the short fibers b are crimped because dust is easily collected. At that time, the number of crimps is preferably within a range of 1 to 30/2.54 cm. Moreover, it is preferable that the crimping ratio is within a range of 8 to 40%.

The short fiber b preferably has a fiber length within the range of 20 to 80 mm.
The fiber type of the short fiber b is not particularly limited, and examples thereof include polyester fiber, polyamide fiber, polyolefin fiber, PPS (polyphenylene sulfide) fiber, aramid fiber, and glass fiber. Among them, meta-type aramid fiber (meta-type wholly aromatic polyamide fiber) is preferable in terms of heat resistance. Meta-type aramid fiber is a fiber made of a polymer in which 85 mol% or more of its repeating unit is m-phenylene isophthalamide. Such a meta-type wholly aromatic polyamide may be a copolymer containing the third component within the range of less than 15 mol%.

Such a meta-type wholly aromatic polyamide can be produced by a conventionally known interfacial polymerization method, and the polymer has a degree of polymerization of 0.5 g/100 ml of an N-methyl-2-pyrrolidone solution. Those having a measured intrinsic viscosity (IV) of 1.3 to 1.9 dl/g are preferably used. Examples of commercially available meta-aramid fibers include Conex (trademark), Conex Neo (trademark), Nomex (trademark) and the like.

Further, it is important that the single fiber fineness of the short fibers c is within a range of 0.3 to 4.0 dtex (more preferably 0.4 to 3.2 dtex, and particularly preferably 0.8 to 2.5 dtex). is there. When the single fiber fineness is less than 0.3 dtex, the strength of the fiber itself tends to be small, and the fiber is likely to be ruptured due to the entanglement treatment during the production of the filter cloth, which may reduce the strength of the nonwoven fabric, which is not preferable. On the contrary, when the single fiber fineness is larger than 4.0 dtex, the dust collecting performance is deteriorated, which is not preferable. The single fiber fineness of the short fibers c is preferably larger than the single fiber fineness of the short fibers b.

In addition, the short fiber c preferably has a tensile strength of 2.2 cN/dtex or more (more preferably 2.2 to 6.0 cN/dtex). When the tensile strength is less than 2.2 cN/dtex, the strength of the fiber itself tends to be small, and the fiber is likely to be ruptured due to entanglement treatment during the production of the filter cloth, which may reduce the strength of the nonwoven fabric.

The short fiber c preferably has an elongation of 25% or more (more preferably 25 to 50%). If the elongation is less than 25%, the fibers are likely to be broken by the entanglement treatment during the production of the filter cloth, and the strength of the nonwoven fabric may be reduced.

When the short fibers c are crimped, dust is easily collected, which is preferable. At that time, the number of crimps is preferably within a range of 1 to 30/2.54 cm. Moreover, it is preferable that the crimping ratio is within a range of 8 to 40%.

The short fiber c preferably has a fiber length within the range of 20 to 80 mm.
The fiber type of the short fiber c is not particularly limited, and examples thereof include polyester fiber, polyamide fiber, polyolefin fiber, PPS (polyphenylene sulfide) fiber, aramid fiber, glass fiber and the like. Among them, meta-type aramid fiber (meta-type wholly aromatic polyamide fiber) is preferable in terms of heat resistance. Meta-type aramid fiber is a fiber made of a polymer in which 85 mol% or more of its repeating unit is m-phenylene isophthalamide. Such a meta-type wholly aromatic polyamide may be a copolymer containing the third component within the range of less than 15 mol%.

Such a meta-type wholly aromatic polyamide can be produced by a conventionally known interfacial polymerization method, and the polymer has a degree of polymerization of 0.5 g/100 ml of an N-methyl-2-pyrrolidone solution. Those having a measured intrinsic viscosity (IV) of 1.3 to 1.9 dl/g are preferably used. Examples of commercially available meta-aramid fibers include Conex (trademark), Conex Neo (trademark), Nomex (trademark) and the like.

Here, when the short fibers a and/or the short fibers b and/or the short fibers c are dyeable fibers, it is preferable that dyeing can be perceived by appropriately dyeing different colors. At that time, the short fibers a and/or the short fibers b and/or the short fibers c are preferably dyeable aramid fibers (for example, Conex Neo (trademark)).

In the present invention, a nonwoven fabric A containing the short fibers a and the short fibers b, a base fabric, and a nonwoven fabric B containing the short fibers c are laminated in this order.

Here, in at least one of the non-woven fabric A and the non-woven fabric B (preferably both the non-woven fabric A and the non-woven fabric B), the basis weight is within a range of 100 to 300 g/m ² (more preferably 120 to 250 g/m ² ). Is preferred. If the basis weight is less than 100 g/m ² , the dust collection performance may be reduced. On the contrary, if the basis weight is larger than 300 g/m ² , the pressure loss may increase.

The types of the non-woven fabrics of the non-woven fabric A and the non-woven fabric B are not particularly limited, and may be any of needle-punched non-woven fabric, spunlace non-woven fabric, wet-laid non-woven fabric, and the needle-punched non-woven fabric is preferable.

The base cloth is also referred to as a scrim, which serves as a strength retaining layer in a filter cloth for bag filters, and prevents pressing force to the dust collection layer due to exhaust gas or the like, and loosening due to its own weight of the dust collection layer itself. It is provided for this purpose.

The fibers constituting the base fabric are not particularly limited, but meta-aramid fibers are preferable from the viewpoint of heat resistance. At that time, the single fiber fineness is preferably in the range of 1.0 to 3.0 dtex. A spun yarn made of short fibers having a fiber length of 20 to 80 mm is preferable. As the count, twin yarn or single yarn of 5 to 20 count is preferable.

The fabric structure of the base fabric is not limited, and may be a woven fabric, a non-woven fabric, or a knitted fabric, but a woven fabric is preferable for obtaining excellent strength. At that time, a flat weave is preferable as the weave. The weave density is preferably in the range of 5 to 20 threads/2.54 cm.

The basis weight of the base fabric is preferably in the range of 30 to 150 g/m ² . If the basis weight is less than 30 g/m ² , the strength may decrease. Conversely, if the basis weight is greater than 150 g/m ² , pressure loss may increase.

As the method for producing the filter cloth for bag filters of the present invention, it is preferable to laminate the non-woven fabric A, the base fabric and the non-woven fabric B in this order and then perform needle punching. Further, it is preferable to carry out calendering next.

At that time, it is preferable to use the one having specifications of upper and lower metal rollers for calendering. It is preferable that the temperature is 100 to 330° C. at the upper and lower sides and the linear pressure is in the range of 50 to 200 kg/cm. When the dust collecting surface side of the filter cloth is burnt by a burner or the surface of the aramid fiber is coated with a treatment agent composed of an oxide of a metal such as silicon or aluminum, and a fluororesin, the fiber is deteriorated. This is preferable because the filtration cloth is suppressed and the durability of the filter cloth is improved, and the dust collection efficiency is improved.

In the filter cloth for bag filter thus obtained, the porosity is preferably in the range of 55 to 90%. If the porosity is less than 55%, the pressure loss is too high, which may not lead to energy saving. On the other hand, if the porosity exceeds 90%, the collection performance may decrease. The porosity can be adjusted by calendering.

Since the non-woven fabric for bag filter filtration cloth of the present invention has the above-mentioned constitution, it is excellent in collecting performance, has low pressure loss, can suppress fluff fall, and can detect mixed fiber spots. Further, when all the fibers constituting the filter cloth for the bag filter are meta type aramid fibers, it also has excellent heat resistance. When using the filter cloth for bag filters of the present invention, it is preferable that the non-woven fabric A is arranged on the filtered material collecting surface side.

Next, Examples and Comparative Examples of the present invention will be described in detail, but the present invention is not limited thereto. Each measurement item in the examples was measured by the following method.
(1) Fiber length, single fiber fineness, tensile strength/elongation, number of crimps, and crimp rate Measured according to JIS L 1015. Table 2 shows the physical properties of raw cotton.
(2) Unit weight and thickness of the nonwoven fabric It was evaluated according to JIS L1096. The thickness was evaluated with a load of 5 g/m ² .
(3) Air dust collection rate The air dust was adjusted to a wind velocity of 5.1 cm/sec, the air dust before and after the sample was counted by a particle counter, and the collection efficiency was calculated by the ratio. ◯: more than 0.3 μm 45%, Δ: 0.3 μm 36-45%, x: less than 36%.
Atmospheric dust collection efficiency (%) = (1-(number of atmospheric dust after passing sample / number of atmospheric dust before passing sample)) x 100
(4) Pressure loss (pressure loss)
The pressure before and after passing through the test piece was measured at the time of measuring the atmospheric dust collection efficiency, and the pressure difference was determined as the pressure loss. ◯: less than 300 Pa, x: evaluated to 300 Pa or more.
(5) Porosity It was measured by 100-100×(density÷specific gravity 1.38).
The density was calculated by unit weight/thickness/1000.
(6) Dyeing property Cationic dye (Nippon Kayaku Co., Ltd., trade name: Kayacryl Blue GSL-ED (B-54)) 6% owf, acetic acid 0.3 mL/L, sodium nitrate 20 g/L, benzyl as a carrier agent A dyeing solution containing 70 g/L of alcohol and 0.5 g/L of a dyeing auxiliary agent (manufactured by Meisei Chemical Industry Co., Ltd., trade name: Disper TL) as a dispersant is prepared. Subsequently, the bath ratio of the fiber to the dyeing solution is set to 1:40, and the dyeing treatment is carried out at 120° C. for 60 minutes. After the dyeing treatment, a treatment liquid containing hydrosulfite 2.0 g/L, amylazine D (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: amylazine D) 2.0 g/L, and sodium hydroxide 1.0 g/L. Was subjected to reduction washing with a bath ratio of 1:20 at 80° C. for 20 minutes, washed with water and then dried to dye. If there is a mixture of a dyed portion and a non-dyed portion visually, there is a dyeing difference. If the colored area of 80% or more of the total area is only a dyed portion or no dyeing, there is no dyeing difference.
(7) Fluff shedding inhibition property Since it depends on the fineness of the composition, the size of the number of components on the collection surface side in Comparative Example 4 is set to ◯×, and the fluff detachment suppression property by thermocompression bonding of the fibers is observed by the SEM surface. The cross-section was checked for fiber deformation, and if there was deformation or adhesion, it was judged to be thermocompression bonded and the fluff fall-off prevention property was evaluated as good. If there is no crimping, it is described as nothing.
(Scrim)
Consisting of meta-aramid fibers (manufactured by Teijin Limited, Conex (trade name), single fiber fineness 2.2 dtex, fiber length 51 mm), the warp uses 10-count twin yarn, and weave density: 20/2.54 cm, The weft yarn is a plain woven fabric having a woven density of 14 yarns/2.54 cm, using a 20th single yarn.
(Calendar processing)
Using the upper and lower metal roller specifications, the upper and lower rollers were appropriately adjusted at a temperature of about 200° C. to 330° C. and a linear pressure of about 100 kg/cm to obtain the target thickness and porosity. .

[Example 1]
The raw material is 0.5 dtex of raw cotton made of meta-aramid fiber (shown as "0.5T" in Table 1) with a cut length of 38 mm, and 1.7 dtex of raw cotton made of dyeable meta-aramid fiber ("1" in Table 1). 0.7TCDT)) and carding the cut length of 51 mm to form a non-woven fabric A, and a raw cotton 2.2 dtex (shown as "2.2T" in Table 1) made of meta-type aramid fiber to cut the cut length of 51 mm. After carding, the non-woven fabric B is used, and the basis weight of the non-woven fabric A on the filtration material collecting surface side is about 200 g/m ² , the non-woven fabric B on the opposite side is about 200 g/m ² , and the basis weight is 70 g/m ^2. Was laminated in the middle, needle punched, and calendered at 200°C. As the raw cotton of 1.7 dtex, cation dyeable cotton, "Conex Neo (trademark)" manufactured by Teijin Ltd. was used.

The obtained sample was evaluated for the basis weight, thickness, porosity, air dust collection rate, pressure loss, presence or absence of dyeing property, and presence or absence of thermocompression bonding by SEM. The evaluation results are shown in Table 1.

[Example 2]
The raw material is 0.5 dtex of raw cotton made of meta-aramid fiber and 38 mm in cut length and 51 mm in cut length at 1.7 dtex are mixed and carded to make a non-woven fabric A, and 2.2 dtex of raw cotton made of meta-aramid fiber is used. A cut length of 51 mm was used as the non-woven fabric B after carding, the non-woven fabric A on the filtration material collecting surface side had a basis weight of about 200 g/m ² , and the non-woven fabric B on the opposite side had a basis weight of about 200 g/m ² and a basis weight of 70 g/m ² . The scrim was used as a base fabric, laminated in the middle, needle punched, and calendered at 330°C. As the raw cotton of 1.7 dtex, cation dyeable cotton, "Conex Neo (trademark)" manufactured by Teijin Ltd. was used.

The obtained sample was evaluated for the basis weight, thickness, porosity, air dust collection rate, pressure loss, presence or absence of dyeing property, and presence or absence of thermocompression bonding by SEM. The evaluation results are shown in Table 1.

[Example 3]
The material is carded by mixing 0.5 mm raw cotton made of meta-aramid fiber with a cut length of 38 mm and a cut length of 51 mm at 1.7 dtex, and then carding it into a non-woven fabric A, and cut it with 2.2 dtex of raw cotton made of meta-aramid fiber. Non-woven fabric B after carding a length of 51 mm,
The non-woven fabric A on the filtration material collecting surface side has a basis weight of about 200 g/m ² , the non-woven fabric B on the opposite side thereof has a basis weight of about 200 g/m ² , and a scrim having a basis weight of 70 g/m ² is used as a base fabric and laminated in the middle to form a needle. It was punched and calendered at 330°C. As the raw cotton of 1.7 dtex, cation dyeable cotton, "Conex Neo (trademark)" manufactured by Teijin Ltd. was used.

The obtained sample was evaluated for the basis weight, thickness, porosity, air dust collection rate, pressure loss, presence or absence of dyeing property, and presence or absence of thermocompression bonding by SEM. The evaluation results are shown in Table 1.

[Comparative Example 1]
The raw material is 2.2dtex of raw cotton made of meta-aramid fiber and the cut length is 51mm. The raw length of 2.2dtex made of meta-aramid fiber is cut individually and the cut length is 51mm. about 200 g / ^{m 2,} at the opposite side of the nonwoven basis weight of about 200 g / ^{m 2,} subjected to needle punching in the middle to be laminated scrim having a basis weight of 70 g / ^{m 2} as a base fabric was subjected to calendering at 200 ° C..

The obtained sample was evaluated for the basis weight, thickness, porosity, air dust collection rate, pressure loss, presence or absence of dyeing property, and presence or absence of thermocompression bonding by SEM. The evaluation results are shown in Table 1.

[Comparative example 2]
The raw material is 1.7 dtex of raw cotton made of meta-aramid fiber and the cut length is 51 mm, and 2.2 dtex of raw cotton made of meta-aramid fiber is cut, and the cut length is 51 mm. about 200 g / ^{m 2,} at the opposite side of the nonwoven basis weight of about 200 g / ^{m 2,} subjected to needle punching in the middle to be laminated scrim having a basis weight of 70 g / ^{m 2} as a base fabric was subjected to calendering at 200 ° C.. As the raw cotton of 1.7 dtex, cation dyeable cotton, "Conex Neo (trademark)" manufactured by Teijin Ltd. was used.

The obtained sample was evaluated for the basis weight, thickness, porosity, air dust collection rate, pressure loss, presence or absence of dyeing property, and presence or absence of thermocompression bonding by SEM. The evaluation results are shown in Table 1.

[Comparative Example 3]
The raw material is 1.7 dtex of raw cotton made of meta-aramid fiber and the cut length is 51 mm, and 2.2 dtex of raw cotton made of meta-aramid fiber is cut, and the cut length is 51 mm. about 200 g / ^{m 2,} at the opposite side of the nonwoven basis weight of about 200 g / ^{m 2,} subjected to needle punching in the middle to be laminated scrim having a basis weight of 70 g / ^{m 2} as a base fabric was subjected to calendering at 330 ° C.. As the raw cotton of 1.7 dtex, cation dyeable cotton, "Conex Neo (trademark)" manufactured by Teijin Ltd. was used.

The obtained sample was evaluated for the basis weight, thickness, porosity, air dust collection rate, pressure loss, presence or absence of dyeing property, and presence or absence of thermocompression bonding by SEM. The evaluation results are shown in Table 1.

[Comparative Example 4]
The raw material is 0.5 dtex of raw cotton made of meta-aramid fiber and the cut length is 38 mm. The length of raw cotton made of meta-aramid fiber is 2.2 dtex and the cut length is 51 mm. about 200 g / ^{m 2,} at the opposite side of the nonwoven basis weight of about 200 g / ^{m 2,} subjected to needle punching in the middle to be laminated scrim having a basis weight of 70 g / ^{m 2} as a base fabric was subjected to calendering.

The obtained sample was evaluated for the basis weight, thickness, porosity, air dust collection rate, pressure loss, presence or absence of dyeing property, and presence or absence of thermocompression bonding by SEM. The evaluation results are shown in Table 1.

According to the present invention, it is excellent in collection performance, has low pressure loss, and can suppress fluff shedding, and further, deterioration of dust collecting property due to wear and cracks is unlikely to occur, preferably for a bag filter capable of detecting mixed fiber spots. A filter cloth and a manufacturing method thereof are provided, and their industrial value is extremely high.

Claims (7)

A non-woven fabric A containing a short fiber a having a single fiber fineness of 0.3 to 0.9 dtex and a short fiber b having a single fiber fineness of 0.9 to 4.0 dtex, a base fabric, and a single fiber fineness of 0.3 to 4 A filter cloth for a bag filter, characterized in that a non-woven fabric B containing 0.0 dtex short fibers c is laminated in this order. The bag cloth filter cloth according to claim 1, wherein the short fibers a and/or the short fibers b and/or the short fibers c are dyeable fibers. The filter cloth for bag filters according to claim 1 or 2, wherein the short fibers a and/or the short fibers b and/or the short fibers c are dyeable aramid fibers. The filter cloth for bag filters according to any one of claims 1 to 3, wherein all fibers constituting the filter cloth for bag filters are meta-aramid fibers. The bag cloth filter cloth according to any one of claims 1 to 4, wherein the porosity is in the range of 55 to 90%. The bag cloth filter cloth according to any one of claims 1 to 5, wherein the non-woven fabric A is arranged on the filtered material collecting surface side. The method for producing a filter cloth for a bag filter according to claim 1, wherein the non-woven fabric A, the base fabric and the non-woven fabric B are laminated in this order, needle punched, and then calendered. Fabric manufacturing method.