JPH11226328A - Filtering material and filter employing thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet of a filtering material capable of collecting dust from coarse size to fine size and durable for long time use and to provide a filter employing the filtering material. SOLUTION: This filtering material is a nonwoven fabric produced by mixing 5 mass % or higher extremely thin fiber with average fiber diameter of 0.1-10 μm and 50-95 mass % of thermally fusible fiber with an average fiber diameter of 10-100 μm which are made of a melt blow method and melting the thermally fusible fiber. This filter comprises the filtering material so arranged as to keep the filtration face at 90 deg. to the flow direction of a liquid to be filtered or at angle besides 90 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter medium for fluids (gas, liquid, etc.), and more particularly to a filter medium having a performance from a dust filter to a high-performance filter in one sheet. Also, the present invention relates to a filter using the filtering material.

[0002]

2. Description of the Related Art Conventionally, a non-woven fabric made of ultrafine fibers having an average fiber diameter of several μm manufactured by a melt blow method has been known as a filter material for a medium / high performance filter. Although the filter medium made of this ultrafine fiber is suitable for collecting fine dust, if coarse dust is collected together, the pressure loss increases immediately and cannot be used for a long time. Was something. For this reason, a bulky filter medium made of fibers thicker than the ultrafine fibers and having a thickness of about 10 to 30 mm is arranged on the upstream side of the processing fluid from the filter medium made of the ultrafine fibers to capture coarse dust. I was gathering.

However, when such a bulky filter material is used in combination, a large space is required because a space occupied by the bulky filter material and a space occupied by the filter material made of ultrafine fibers are required. There was a problem of doing.

In the case where these two filter media are used in combination, a filter is manufactured by fixing a filter composed of ultrafine fibers to a frame or the like, and a process of installing the filter is performed. , A filter is required to be manufactured, and two works of installing the filter are required, which is very complicated in manufacturing and installing the filter.

[0005] Furthermore, since the filter medium made of the above-mentioned ultrafine fibers is composed of the ultrafine fibers, the pressure loss increases.
For this reason, in order to reduce the pressure loss or to increase the filtration area and extend the service life, folding or bag-like processing has been performed. In this case, there is a problem that the process is complicated since a process of folding the filter material or processing into a bag-like material is required.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is possible to collect from coarse to fine dust with one filter medium, An object of the present invention is to provide a filter material that can be used and a filter using the filter material.

[0007]

The filter medium of the present invention has an average fiber diameter of 0.1 to 1 produced by a melt blow method.
0 μm ultrafine fiber 5 mass% or more and less than 50 mass%, heat-fusible fiber 5 having an average fiber diameter of 10 to 100 μm
0 mass% or more and 95 mass% or less are mixed, and the non-woven fabric is formed by fusing the heat-fusible fibers.

[0008] As described above, the filter medium of the present invention has a large average fiber diameter of 10 to 100 µm and is mainly composed of rigid heat-fusible fibers, and a relatively coarse space is formed by the heat-fusible fibers. Therefore, coarse dust can be collected and the pressure loss can be reduced, so that it can be used for a long time. Moreover, in addition to the heat-fusible fiber, an average fiber diameter of 0.1 produced by a melt blowing method is used.
Since fine fibers of 10 to 10 μm are mixed, fine dust can be collected. Therefore, the filter medium of the present invention can collect from coarse dust to fine dust with one filter medium, and can be used for a long time.

[0009] In one of the filters of the present invention, the filtering surface of the filtering material is disposed at an angle of 90 ° with respect to the inflow direction of the processing fluid. Therefore, the filter can collect from coarse dust to fine dust in a narrow space, and can be used for a long time.

[0010] In another filter of the present invention, the filtering surface of the filtering medium is arranged at an angle other than 90 ° with respect to the inflow direction of the processing fluid. Therefore, the filter has a lower pressure loss and can be used for a longer period of time.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The filter medium of the present invention is obtained by using ultra-fine fibers having an average fiber diameter of 0.1 to 10 .mu.m produced by a melt blow method for 5 m so that fine dust can be collected.
ass% or more and less than 50 mass%.

The conditions for producing ultrafine fibers by the meltblowing method are not particularly limited. For example, they can be produced under the following conditions. That is, with an orifice diameter of 0.1 to 0.5 mm and a pitch of 0.3 to 1.2 mm
Is heated to a temperature of 220 to 370 ° C. and 0.02 to 1.5 g / m per orifice
The fibers are discharged at a rate of in. Ultrafine fibers can be produced by applying air to the discharged fibers at a temperature of 220 to 400 ° C. and a mass ratio of 5 to 2,000 times the amount of discharged fibers.

The ultrafine fibers produced in this manner have an average fiber diameter of 0.1 to 10 μm. When the average fiber diameter of the ultrafine fibers is less than 0.1, the pressure loss tends to be high, so that it is difficult to produce a filter material that can be used for a long time, while the average fiber diameter exceeds 10 μm. This tends to make it difficult to collect fine dust. Ultrafine fibers having an average fiber diameter of 0.25 to 5 μm are preferred.

The average fiber diameter in the present invention refers to the average value of the fiber diameter at 200 points of fibers (for example, ultrafine fibers). The fiber diameter can be easily measured, for example, from an electron micrograph of a cut section obtained by cutting the filter medium in the thickness direction. When the cross-sectional shape of the fiber is non-circular, the diameter of a circle having the same area as the cross-sectional area of the fiber is regarded as the fiber diameter.

Examples of the resin component constituting the ultrafine fibers produced by the melt blow method include polyolefin resins such as polypropylene and polyethylene.
It can be composed of one or more kinds of polyester resin, polyamide resin, polycarbonate resin, urethane resin and the like. Among these, it is preferable that the surface of the ultrafine fiber contains a polyolefin-based resin that is easy to produce ultrafine fibers and that is easily electretized, and it is more preferable that the surface of the ultrafine fiber contains a polypropylene-based resin.

It is necessary that the ratio of such ultrafine fibers in the filter medium is not less than 5 mass% and less than 50 mass%. When the amount of the ultrafine fibers is less than 5 mass%, the amount of the ultrafine fibers tends to be too small to collect fine dust. On the other hand, when the amount is more than 50 mass%, the particles are immediately clogged by coarse dust. It is preferably 7 to 40% by mass,
More preferably, it is 30 mass%.

The filter medium of the present invention comprises, in addition to the above-described ultrafine fibers, 5 heat-fusible fibers having an average fiber diameter of 10 to 100 μm.
0 mass% or more and 95 mass% or less, and this heat-fusible fiber is fused. Therefore, a relatively coarse space can be formed, coarse dust can be collected, and pressure loss can be reduced, so that the device can be used for a long time.

The average fiber diameter of the heat-fusible fiber is 10 to 1
When the average fiber diameter is less than 10 μm, the pressure loss is high because a relatively coarse space cannot be formed, and there is a tendency that it cannot be used for a long time. On the other hand, when the average fiber diameter exceeds 100 μm, The space formed by the heat-fusible fibers is too large, and there is a tendency that fine dusts cannot be collected even when ultrafine fibers are mixed. Therefore, the thickness is more preferably 20 to 50 μm.

The heat-fusible fibers include, for example, polyolefin resins such as polypropylene and polyethylene,
It may be a single-molten type such as polyester-based resin, polyamide-based resin, polycarbonate-based resin, urethane-based resin, or a composite type including two or more of these resins. Among these, the latter composite type can be suitably used because the fiber shape can be maintained by the resin component that does not fuse, and the space formed by the heat-fusible fibers is excellent in retention.

The preferred composite heat-fusible fibers include, for example, (1) a resin component having a high melting point as a core component, and a resin component having a lower melting point than the resin component having a higher melting point as a sheath component (fusible component). (2) a side-by-side type in which a resin component having a high melting point and a resin component (fusing component) having a lower melting point than the resin component having a higher melting point are bonded together. And (3) a sea-island type in which a low melting point resin component (a sea component and a fusion component) contains a large number of resin components having a higher melting point than the low melting point resin component. Among these, a core-sheath type, eccentric type, or sea-island type heat-fusible fiber that hardly reduces the space due to heat at the time of heat fusion or lowers the form stability can be preferably used.

The difference in melting point between the high melting point component and the low melting point component (fusing component) of the composite type heat fusible fiber is preferably at least 10 ° C. so as not to melt any resin component.
More preferably, the temperature is 0 ° C. or higher. In addition, when the ultra-fine fibers are also fused when the heat-fusible fibers are fused, fine dust cannot be collected. Therefore, the low melting point component (fused component) of the heat-fusible fibers is It is preferably lower than the melting point of the ultrafine fiber (when the ultrafine fiber is composed of a plurality of resin components, based on the resin component having the lowest melting point) by 10 ° C. or more,
It is more preferable that the temperature is lower by 20 ° C. or more. For example, as described above, when the ultrafine fiber is made of a suitable polypropylene resin, the melting point of the fusion component of the heat fusible fiber is preferably 150 ° C. or less, more preferably 140 ° C. or less. In this case, the fusion component of the heat-fusible fiber is preferably made of polyethylene resin.

The heat-fusible fiber may be a long fiber or a short fiber, but is preferably a short fiber so as to be able to exist in a state of being uniformly mixed with the ultrafine fiber. In the case of short fibers, the fiber length is preferably from 5 to 160 mm, and more preferably from 25 to 110 mm so as to be easily entangled with the ultrafine fibers.

When the heat-fusible fibers are drawn, they are excellent in strength and rigidity, and can maintain a relatively coarse space formed by the heat-fusible fibers. Can be used for

The heat-fusible fibers occupy 50 mass% or more of the filter medium so that a relatively coarse space can be formed, and it is necessary to mix ultrafine fibers.
is occupying. Preferably 60 to 93 mass% of the filter material
, More preferably 70 to 90 mass%.

The heat-fusible fibers need not be composed of one kind, and two or more kinds of heat-fusible fibers differing in fiber diameter, composition, fiber length and the like may be mixed. In particular, by mixing two or more types of heat-fusible fibers having different fiber diameters, a more suitable space can be formed, which is preferable. In terms of the average fiber diameter, there is a difference of about 10 to 50 μm. It is preferable to mix two or more types of conductive fibers.

The filter medium of the present invention is mainly composed of ultrafine fibers and heat-fusible fibers.
Synthetic fibers such as nylon fibers, vinylon fibers, polyester fibers, acrylic fibers, polyethylene fibers, polypropylene fibers, and polyurethane fibers, and functional fibers for imparting various properties can be mixed.

Examples of the functional fiber include vinylidene fiber, polyvinyl chloride fiber, polyclar fiber, or modified acrylic fiber for imparting flame retardancy, and silver or copper for imparting antibacterial properties. Fibers containing such as can be mixed. In addition, functional fibers having functions such as antistatic property, deodorizing property, deodorizing property, and moisture absorbing property can be mixed. A functional substance having these functions may be mixed in the ultrafine fibers and / or the heat-fusible fibers.

When the polyolefin fiber and the acrylic fiber and / or the modified acrylic fiber are mixed, it can be charged by friction.

The fibers other than the ultrafine fibers and the heat-fusible fibers (hereinafter referred to as "other fibers") collect fine dust by the ultrafine fibers and form a relatively coarse space by the heat-fusible fibers. It is necessary that the content is not more than 45 mass% of the filter material so as not to prevent the filtration.

The other fiber may be a long fiber or a short fiber, but is a short fiber so that it can exist in a state of being uniformly mixed with an ultrafine fiber or a heat-fusible fiber. Is preferred. In the case of short fibers, the fiber length is 5 to 160 mm
Is preferably, and more preferably 25 to 110 mm.

Further, the other fiber should have a melting point higher by at least 10 ° C. than the melting point of the fusion component of the heat fusible fiber so as not to be melted by heat at the time of fusing the heat fusible fiber. More preferably, it has a melting point higher by 20 ° C. or more.

The filter medium of the present invention is a nonwoven fabric in which the above-mentioned fibers are mixed, preferably uniformly mixed, and heat-fusible fibers are fused. The filter medium of the present invention can be composed of only the organic fibers as described above, and can be incinerated at the end of the service life of the filter medium.

The thickness of the filter medium (ie, nonwoven fabric) of the present invention is preferably 5 to 50 mm. 5m thick filter media
When the thickness is less than m, a relatively coarse space cannot be formed by the heat-fusible fiber, so that the pressure loss is high, and there is a tendency that it cannot be used for a long time. However, the thickness is more preferably 5 to 25 mm, because there is a tendency that a portion not involved in the filtration tends to be increased, and in the case of unit processing, the processing tends to be difficult. Note that this thickness is 1 cm in unit area.
The value at the time of loading 1 g per ²

The areal density of the filter is 50 to 500 g /
m ² is preferred. When the areal density is less than 50 g / m ² , the density of the fibers tends to be too low and it becomes difficult to collect fine dust, while on the other hand, 500 g / m ^2.
If the ratio exceeds 100 g, the density of the fibers becomes too high, and the fibers tend to be clogged by coarse dust immediately and cannot be used for a long time, so that the weight is more preferably 100 to 300 g / m ² .

Further, the apparent density of the filter material is 0.001 to
It is preferably 0.1 g / cm ³ . The apparent density is 0.
If it is less than 001G / cm ^3, tend to be difficult to collect the fine dust, while, 0.1 g / cm ³
Exceeds 0.0, coarse dust tends to cause clogging immediately and make it unusable for a long time.
More preferably, it is 1 to 0.05 g / cm ³ .

The filter material of the present invention can be manufactured, for example, as follows. First, as shown in FIG. 1, the flow of the ultrafine fibers 2 discharged from the melt-blowing apparatus 1 under the above-described conditions is applied to the heat-fusible fibers 4 (and optionally other fibers) spread by the spreader 3. ), And after mixing the two, the mixed fibers are collected by a collector 5 such as a conveyor to form a fiber web 6. Next, the fiber web 6 is subjected to a heat treatment to fuse only the heat-fusible fibers 4 to produce the nonwoven fabric 8 of the present invention, that is, a filter material.

Examples of the spreader 3 for supplying the heat-fusible fiber 4 include a card machine and a garnet machine.
The fiber opening machine 3 in which a plurality of fiber opening cylinders 31 are accommodated in a housing 32 as shown in FIG. 2 can make the heat-fusible fibers 4 collide with the flow of the microfine fibers 2 vigorously. Can be preferably used because it can be uniformly mixed with the ultrafine fibers 2 also in the thickness direction. Further, the fiber opening machine 3 has a fiber length of 25 to 1 which is suitable in the present invention.
Even fibers of about 10 mm can be uniformly opened.

When the heat-fusible fiber 4 is supplied by the opening device 3, it is preferable that the heat-fusible fiber 4 is supplied from a direction perpendicular to the flow of the ultrafine fiber 2 as much as possible so that the fiber can be mixed more uniformly with the ultrafine fiber 2. preferable. For example, melt blow device 1
When the flow of the ultrafine fibers 2 discharged from the nozzle is formed in the horizontal direction, the heat-fusible fibers 4 may be naturally dropped from above the flow of the ultrafine fibers 2 and supplied. Since the flow of the microfibers 2 discharged from the melt blow device 1 is the same as the direction in which gravity acts, the heat-fusible fibers 4 supplied from the spreader 3 are moved from a direction perpendicular to the direction in which gravity acts. Preferably, it is supplied. In the spreader 3 of FIG. 2, an air nozzle 33 capable of supplying air is provided so that the heat-fusible fiber 4 can be supplied at such an angle.

It should be noted that the heat fusible fibers 4
By adjusting the angle at which the fiber web 6 is fed,
By changing the abundance ratio of the heat-fusible fibers 4 in the thickness direction, a dense structure can be formed in the thickness direction.

The collector 5 for collecting the fiber web 6 in which the ultrafine fibers 2 and the heat-fusible fibers 4 are mixed may be in the form of a roll or a net. The collecting body 5 is preferably air-permeable so that the fiber web 6 is not disturbed or scattered due to collision with the air flow that transports the fiber, and furthermore, a device capable of sucking and removing the air flow is provided on the side opposite to the collecting surface. Is preferred.

In the present invention, the heat treatment is performed using the heat fusible fiber 4.
It is preferable to perform the heat treatment at a temperature not lower than the melting point of the fusion component and lower than the melting point of the ultrafine fibers 2 (including other fibers in some cases) without substantially applying pressure. By doing so, the ultrafine fibers 2 do not turn into a film, and the original collection performance can be exhibited. Further, the relatively coarse space formed by the heat-fusible fibers is not impaired, and the pressure loss is reduced. Since the height does not increase, it is possible to manufacture the filter medium 8 that can be used for a long time. Further, the bulky filtration material 8 can be manufactured in which the fusion is not biased to the vicinity of the surface of the filtration material 8 and the inside of the filtration material 8 is firmly fused.

Examples of the heat treatment apparatus 7 capable of performing such a heat treatment include a hot air circulation type dryer,
There is a suction type air through dryer. For example, when the ultrafine fibers are made of a polypropylene resin and the fusion component of the heat-fusible fibers is made of a polyethylene resin, it is preferable to perform the fusion by setting the atmosphere temperature of the heat treatment device 7 to 140 to 150 ° C.

In order to adjust the thickness of the filter medium after the heat treatment, the filter medium may be passed between rolls at a temperature lower than the melting point of any of the fibers constituting the filter medium 8, or may be passed between flat presses. Also, in order to increase the collection efficiency,
The electretization process may be performed after the fusion process. In the case of electretization treatment, in order to further increase the efficiency, it is preferable to reduce the fiber oil agent of the heat-fusible fiber by washing with water or hot water as much as possible.

Before, simultaneously with, or after the heat treatment, the fibers may be bonded to each other with an adhesive such as an emulsion or a latex. Because
In many cases, these adhesives do not bond. Before or after the heat treatment, the fibers may be entangled with a needle or a fluid flow.

In the filter of the present invention, the filtration surface of the above-mentioned filter medium is arranged at an angle of 90 ° or an angle other than 90 ° with respect to the inflow direction of the processing fluid.
Since the former filter uses the above-mentioned filter material, it can collect from coarse dust to fine dust in a narrow space, and can be used for a long period of time. Because of the use of, it is possible to collect from coarse dust to fine dust, and it can be used for a longer period of time due to lower pressure loss.

The "filtering surface" of the filtering material is a surface perpendicular to the thickness direction of the filtering material and on the inflow side of the processing fluid. Further, “the filtering surface is disposed at an angle of 90 ° with respect to the inflow direction of the processing fluid” means that the filtering surface is assumed to be a straight line that indicates the inflow direction of the processing fluid and a smooth plane
The angle between the vertical direction is 90 ° and the angle between the straight line indicating the inflow direction of the processing fluid and the horizontal direction of the filtration surface is 9 °.
0 ° means that “the filtration surface is disposed at an angle other than 90 ° with respect to the inflow direction of the processing fluid” means that a straight line indicating the inflow direction of the processing fluid and the vertical direction of the filtration surface. This means that the angle is not 90 °, the angle between the straight line indicating the inflow direction of the processing fluid and the horizontal direction of the filtration surface is not 90 °, or none of the angles is 90 °.

More specifically, as shown in FIG. 3, the former filter is obtained by fixing the above-mentioned filter material 8 in a flat plate shape with a frame member 9, and the latter filter is made as shown in FIG. 5, one or more of the above-described filtering materials 8 formed into a bag shape and one or more fixed with a frame material 9 or, as shown in FIG. There are fixed ones.

The frame material 9 may be made of, for example, aluminum, aluminum alloy, stainless steel, or various resins. The fixing of the filter media 8 as shown in FIGS. 4 and 5 can be performed by heat sealing or sewing. Further, the integration of the filter member 8 and the frame member 9 can be performed by interposing a thermoplastic hot melt resin such as polyvinyl acetate between the frame member 9 and the filter member 8.

Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0050]

(Example 1) A nozzle piece arranged at an orifice diameter of 0.2 mm and a pitch of 0.8 mm was heated to a temperature of 320 ° C.
To 0.04 g / min per orifice
, Polypropylene fibers were discharged at a rate of Air at a temperature of 340 ° C. and a mass ratio of 75 times was applied to the discharged polypropylene fibers to form a flow of the ultrafine fibers 2 having an average fiber diameter of 1.5 μm in the same direction as the direction in which gravity acts.

At right angles to the flow of the ultrafine fibers 2, two opening cylinders 31 as shown in FIG.
2 from the opening machine 3 equipped with the air nozzle 33,
The core component is made of a polypropylene resin (melting point: 160 ° C.), the sheath component is made of polyethylene resin (melting point: 135 ° C.), and the core-sheath type heat-fusible fiber having a fiber diameter of 31 μm and a fiber length of 102 mm is 70 mass%. Component is made of polypropylene resin (melting point 160 ° C), sheath component is made of polyethylene resin (melting point 135 ° C), fiber diameter 52μ
m, a stretched core-sheath type heat-fusible fiber having a fiber length of 102 mm and a mass of 30 mass%, and the polypropylene fine fiber 2
And mixed. The mixed fibers were collected by a mesh conveyor to form a fiber web 6. Air was removed by suction from the side opposite to the collecting surface of the conveyor to prevent the fiber web 6 from being disturbed.

Next, the fiber web 6 was heated to a temperature of 145 ° C.
By passing through a dryer in an atmosphere for 3 minutes, only the sheath component (polyethylene component) of the core-sheath type heat-fusible fiber is fused, and the surface density is 250 g / m ² , the thickness is 25 mm, and the apparent density is 0.01 g. / Cm ³ of filter medium 8 was produced. In addition, this filtration material 8 is 50 g / m ² of polypropylene ultrafine fibers ^2.
(20 mass%) and 200 g / m ² (80 mass%) of the core-sheath type heat-fusible fiber. The pressure loss at a surface velocity of 50 cm / s of the filter medium 8 was measured according to JIS.
It was 115 Pa when measured with a pressure loss measuring instrument (type 1) specified in B 9908. Also, 0.
The collection efficiency for 3 μm air dust is 29% and 1 μm
The collection efficiency against atmospheric dust was 91%.

(Example 2) A nozzle piece arranged at an orifice diameter of 0.2 mm and a pitch of 0.8 mm was heated at a temperature of 340.
° C and 0.07 g / mi per orifice
The polypropylene fibers were discharged at a rate of n. Air at a temperature of 360 ° C. and a mass ratio of 40 times was applied to the discharged polypropylene fibers to form a flow of the ultrafine fibers 2 having an average fiber diameter of 1.5 μm in the same direction as the direction of gravity. Next, at right angles to the flow of the ultrafine fibers 2, the core-sheath type heat-fusible fibers 4 having exactly the same composition as in Example 1 were supplied in exactly the same manner to form a fiber web 6.

Then, in the same manner as in Example 1, only the sheath component (polyethylene component) of the core-sheath type heat-fusible fiber was fused, and the area density was 220 g / m ² , the thickness was 10 mm, and the apparent density was 0.022 g / cm ³ of the filtering material 8 was produced. In addition, this filtering material 8 is 100
g / m ² (45.5mass%) which comprise a core-sheath type heat fusible fibers contained ^{120g / m 2 (54.5mass%)} . The pressure loss at a surface speed of 10 cm / s of the filter medium 8 was measured by a pressure loss measuring instrument (type 1) specified in JIS B 9908, and was found to be 92 Pa. The collection efficiency for 0.3 μm air dust is 75%.
And the collection efficiency with respect to 1 μm atmospheric dust was 99%.

(Comparative Example) A nozzle piece arranged at an orifice diameter of 0.2 mm and a pitch of 0.8 mm was heated at a temperature of 340 ° C.
To 0.07 g / min per orifice
, Polypropylene fibers were discharged at a rate of Air was applied to the discharged polypropylene fibers at a temperature of 360 ° C. and a mass ratio of 40 times to form a flow of the ultrafine fibers 2 having an average fiber diameter of 1.5 μm in the same direction as the direction of gravity. Next, at right angles to the flow of the ultrafine fibers 2,
The core-sheath type heat-fusible fiber 4 having exactly the same composition as in Example 1 was supplied in exactly the same manner to form a fiber web 6.

Next, in the same manner as in Example 1, only the sheath component (polyethylene component) of the core-sheath type heat-fusible fiber was fused, and the area density was 220 g / m ² , the thickness was 10 mm, and the apparent density was 0.022 g / cm ³ of the filtering material 8 was produced. In addition,
This filtering material 8 is composed of 140 g /
m ² (63.6 mass%) and 80 g / m ² (36.4 mass%) of the core-sheath type heat-fusible fiber. The pressure loss at a surface velocity of 10 cm / s of the filter medium 8 was measured by a pressure loss measuring instrument (type 1) specified in JIS B 9908, and was 135 Pa. In addition, the collection efficiency for 0.3 μm air dust is 85%.
And the collection efficiency with respect to 1 μm air dust was 99.5%.

[0057]

The filter material of the present invention is a heat-fusible fiber having an average fiber diameter of 5 mass% or more and less than 50 mass% and an average fiber diameter of 10 to 100 μm, which is produced by a melt blow method. 50 mass% or more,
95% by mass or less, and the non-woven fabric is formed by fusing the heat-fusible fibers. As described above, the filter medium of the present invention has a thick average fiber diameter of 10 to 100 μm and is mainly composed of rigid heat-fusible fibers, and a relatively coarse space is formed by the heat-fusible fibers. Since coarse dust can be collected and the pressure loss can be reduced, it can be used for a long time. In addition to the heat-fusible fibers, ultrafine fibers having an average fiber diameter of 0.1 to 10 μm manufactured by the melt blowing method are mixed,
Even fine dust can be collected. Therefore, the filter medium of the present invention can collect from coarse dust to fine dust with one filter medium, and can be used for a long time.

In one of the filters of the present invention, the filter surface of the filter is disposed at an angle of 90 ° with respect to the inflow direction of the processing fluid. Therefore, the filter can collect from coarse dust to fine dust in a narrow space, and can be used for a long time.

In another filter of the present invention, the filtering surface of the filtering medium is arranged at an angle other than 90 ° with respect to the inflow direction of the processing fluid. Therefore, the filter has a lower pressure loss and can be used for a longer period of time.

[Brief description of the drawings]

FIG. 1 is a process chart showing an example of a manufacturing process of a filter medium.

FIG. 2 is a schematic cross-sectional view of an example of a fiber opening machine.

FIG. 3 is a perspective view of an example of a filter.

FIG. 4 is a perspective view of an example of another filter.

FIG. 5 is a perspective view of an example of another filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melt blow apparatus 2 Ultrafine fiber 3 Spreader 31 Spreading cylinder 32 Housing 33 Air nozzle 4 Heat-fusible fiber 5 Collector 6 Fiber web 7 Heat treatment device 8 Nonwoven fabric (filter material) 9 Frame material

Claims (4)

[Claims] An ultrafine fiber having an average fiber diameter of 0.1 to 10 μm and a mass of not less than 5 mass% and less than 50 mass%, wherein the average fiber diameter is 10 to 100.
μm heat fusible fiber 50 mass% or more, 95 mass
% Or less, and a non-woven fabric in which the heat-fusible fibers are fused. 2. The filter medium according to claim 1, wherein the nonwoven fabric has a thickness of 5 to 50 mm. 3. The filter according to claim 1, wherein the filter surface of the filter medium according to claim 1 or 2 is arranged at an angle of 90 ° with respect to the inflow direction of the processing fluid. 4. The filter according to claim 1, wherein the filtering surface of the filtering medium according to claim 1 or 2 is arranged at an angle other than 90 ° with respect to the inflow direction of the processing fluid.