JP3677385B2 - Filter material and filter using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a filter medium for fluid (gas, liquid, etc.), and more particularly to a filter medium having a performance from a coarse dust filter to a high performance filter in a single sheet. The present invention also relates to a filter using the filter medium.
[0002]
[Prior art]
Conventionally, a nonwoven fabric made of ultrafine fibers having an average fiber diameter of several μm manufactured by a melt blow method is known as a filtering material for medium and high performance filters. This ultrafine fiber filter medium is suitable for collecting fine dust, but if coarse dust is also collected, pressure loss immediately increases and cannot be used for a long time. It was a thing. 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 upstream of the treatment fluid from the filter medium made of the ultrafine fibers to collect coarse dust. I was gathering.
[0003]
However, when such a bulky filter medium is used in combination, a space occupied by the bulky filter medium and a space occupied by the filter medium made of ultrafine fibers are required, so that a large space is required. was there.
[0004]
When these two filter media are used in combination, a filter is manufactured by fixing the filter media made of ultrafine fibers to a frame material, and the operation of installing this filter and fixing the bulky filter material to the frame material etc. In other words, the manufacturing of the filter and the installation of the filter require two operations, which are very complicated in manufacturing and installing the filter.
[0005]
Furthermore, since the filter medium made of the above-mentioned ultrafine fibers is composed of ultrafine fibers, the pressure loss becomes high. Therefore, in order to reduce the pressure loss, or to widen the filtration area and extend the service life, the material has been folded or processed into a bag shape. In this case, there is a problem that it is complicated because a process of folding the filter medium and processing into a bag-like material is required.
[0006]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems, and a filter medium that can collect coarse dust to fine dust with a single filter medium and can be used for a long time, and the filter medium. It is an object to provide a filter using the.
[0007]
[Means for Solving the Problems]
The filter medium of the present invention is produced by a melt blow method, the average fiber diameter is 0.1 to 10 μm ultrafine fiber 5 mass% or more, less than 50 mass%, and the average fiber diameter is 10 to 100 μm heat-fusible fiber 50 mass% or more. , 95 mass% or less, and this heat-fusible fiberBy heat treatment that does not substantially pressurizeFrom a fused non-woven fabricAnd an apparent density of 0.001 to 0.1 g / cm ³ It is characterized by beingThe
[0008]
Thus, the filter medium of the present invention has a mean fiber diameter as thick as 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. Coarse dust can be collected and the pressure loss can be reduced, so that it can be used for a long time. Moreover, since fine fibers having an average fiber diameter of 0.1 to 10 μm produced by the melt blow method are mixed in addition to the heat-fusible fibers, fine dust can also be collected. Therefore, the filter medium of the present invention can collect from coarse dust to fine dust with a single filter medium and can be used for a long time.
[0009]
In one of the filters of the present invention, the filtration surface of the filter medium is disposed at an angle of 90 ° with respect to the inflow direction of the processing fluid. Therefore, it is a filter that 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 filtration surface of the filter medium is disposed at an angle other than 90 ° with respect to the inflow direction of the processing fluid. Therefore, the filter can be used for a longer period because of lower pressure loss.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The filter medium of the present invention contains 5% by mass or more and less than 50% by mass of ultrafine fibers having an average fiber diameter of 0.1 to 10 μm produced by a melt blow method so that fine dust can be collected.
[0012]
Although the conditions for producing ultrafine fibers by this melt blowing method are not particularly limited, for example, they can be produced under the following conditions. That is, nozzle pieces arranged with an orifice diameter of 0.1 to 0.5 mm and a pitch of 0.3 to 1.2 mm are heated to a temperature of 220 to 370 ° C., and 0.02 to 1.5 g / min per orifice. The fiber is discharged at a rate of. An ultrafine fiber can be produced by applying air at a temperature of 220 to 400 ° C. and an amount of air that is 5 to 2,000 times the fiber discharge amount at a mass ratio.
[0013]
The ultrafine fibers thus produced have an average fiber diameter of 0.1 to 10 μm. If the average fiber diameter of the ultrafine fibers is less than 0.1, the pressure loss tends to increase, making it difficult to produce a filter material that can be used for a long time. On the other hand, the average fiber diameter exceeds 10 μm. Then, since it tends to be difficult to collect fine dust, an ultrafine fiber having an average fiber diameter of 0.25 to 5 μm is preferable.
[0014]
In addition, the average fiber diameter in this invention means the average value of the fiber diameter in 200 fibers (for example, ultrafine fiber). This fiber diameter can be easily measured from, for example, an electron micrograph of a cut surface 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.
[0015]
Examples of the resin component constituting the ultrafine fiber produced by the melt blowing method include one or more types such as polyolefin resins such as polypropylene and polyethylene, polyester resins, polyamide resins, polycarbonate resins, and urethane resins. Can be. Among these, it is preferable to include a polyolefin-based resin on the surface of the ultrafine fiber, and more preferable to include a polypropylene-based resin on the surface of the ultrafine fiber, which makes it easy to produce ultrafine fibers and easily electretize.
[0016]
The ratio of such ultrafine fibers to the filter medium needs to be 5 mass% or more and less than 50 mass%. If the ultrafine fiber is less than 5 mass%, the amount of the ultrafine fiber tends to be too small to collect fine dust. Therefore, it is preferably 7 to 40 mass%, more preferably 10 to 30 mass%.
[0017]
The filter medium of the present invention contains 50 mass% or more and 95 mass% or less of heat-fusible fibers having an average fiber diameter of 10 to 100 μm in addition to the ultrafine fibers as described above.By heat treatment that does not substantially pressurizeFused. Therefore, a relatively rough spaceThat is, the apparent density is 0.001 to 0.1 g / cm as described above. ³ Since it is possible to collect coarse dust and reduce pressure loss, it can be used for a long time.
[0018]
The average fiber diameter of this heat-fusible fiber needs to be 10 to 100 μm. If the average fiber diameter is less than 10 μm, a relatively rough space cannot be formed, resulting in a high pressure loss and a tendency that the fiber cannot be used for a long time. On the other hand, if the average fiber diameter exceeds 100 μm, the space formed by the heat-fusible fiber is too large, and even if ultrafine fibers are mixed, there is a tendency that fine dust cannot be collected. And more preferably 20 to 50 μm.
[0019]
This heat-fusible fiber is made of, for example, a one-type all-melt type, such as a polyolefin resin such as polypropylene or polyethylene, a polyester resin, a polyamide resin, a polycarbonate resin, or a urethane resin, or two of these resins. It can be a composite type containing more than one type. Among these, the latter composite type can be preferably used because the fiber shape can be maintained by the resin component that is not fused and the space formed by the heat-fusible fiber is excellent.
[0020]
As this suitable composite-type heat-fusible fiber, for example, (1) a resin component having a high melting point is used as a core component, and a resin component having a lower melting point than this resin component having a high melting point is a sheath component (fusion component). (2) Side-by-side type in which a high melting point resin component and a resin component having a lower melting point than this high melting point resin component (fusion component) are bonded together ( 3) A sea-island type resin in which many low-melting point resin components are scattered in the low-melting point resin component (sea component and fusion component). Among these, a core-sheath type, an eccentric type, or a sea-island type heat-fusible fiber that can reduce the space by heat at the time of heat-sealing or hardly reduce the form stability can be suitably used.
[0021]
The melting point difference between the high melting point component and the low melting point component (fusing component) of the composite heat-fusible fiber is preferably 10 ° C. or higher and 20 ° C. or higher so that neither resin component is melted. Is more preferable. In addition, if the ultrafine fiber is also fused when the heat fusible fiber is fused, it becomes impossible to collect fine dust. Therefore, the low melting point component (fusion component) of the heat fusible fiber is It is preferably 10 ° C. or more lower than the melting point of the ultrafine fiber (when the ultrafine fiber is composed of a plurality of resin components, the resin component having the lowest melting point is used as a reference), more preferably 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, and more preferably 140 ° C. or less. In this case, the fusion component of the heat-fusible fiber is preferably made of a polyethylene resin.
[0022]
The heat-fusible fiber may be a long fiber or a short fiber, but is preferably a short fiber so that it can be present in a state of being uniformly mixed with the ultrafine fiber. In the case of a short fiber, the fiber length is preferably 5 to 160 mm, and more preferably 25 to 110 mm so as to be easily entangled with the ultrafine fiber.
[0023]
Further, when the heat-fusible fiber is drawn, it is excellent in strength and rigidity, and can be suitably used because it can maintain a relatively rough space formed by the heat-fusible fiber. .
[0024]
This heat-fusible fiber occupies 50 mass% or more of the filter medium so that a relatively rough space can be formed, and 95 mass% occupies since it is necessary to mix ultrafine fibers. Preferably it occupies 60-93 mass% of a filter medium, More preferably, it occupies 70-90 mass%.
[0025]
Moreover, this heat-fusible fiber does not need to consist of one type, and two or more types of heat-fusible fibers that differ in terms of fiber diameter, composition, fiber length, etc. may be mixed. Particularly, it is preferable to mix two or more kinds of heat-fusible fibers having different fiber diameters so that a more appropriate space can be formed. In terms of average fiber diameter, there is a difference of about 10 to 50 μm. It is preferable to mix two or more types of hydrophilic fibers.
[0026]
The filter medium of the present invention is mainly composed of ultrafine fibers and heat-fusible fibers. Besides these fibers, nylon fibers, vinylon fibers, polyester fibers, acrylic fibers, polyethylene fibers, polypropylene fibers, polyurethane fibers, etc. Synthetic fibers and functional fibers can be mixed to impart various properties.
[0027]
As this functional fiber, for example, vinylidene fiber, polyvinyl chloride fiber, polyclar fiber, or modified acrylic fiber is mixed to impart flame retardancy, or silver or copper is included to impart antibacterial properties. Fibers can be mixed. In addition, functional fibers having functions such as antistatic properties, deodorizing properties, deodorizing properties, and hygroscopic properties can be mixed. In addition, you may mix the functional substance which has these functions in the said ultrafine fiber and / or a heat-fusible fiber.
[0028]
In addition, if polyolefin fiber and acrylic fiber and / or modified acrylic fiber are mixed, it can be charged by friction.
[0029]
These ultrafine fibers and fibers other than the heat-fusible fibers (hereinafter referred to as “other fibers”) do not interfere with the collection of fine dust by the ultrafine fibers and the formation of a relatively coarse space by the heat-fusible fibers. Thus, it is necessary to be 45 mass% or less of the filter medium.
[0030]
The other fibers may be long fibers or short fibers, but are preferably short fibers so that they can exist in a state of being uniformly mixed with ultrafine fibers or heat-fusible fibers. In the case of short fibers, the fiber length is preferably 5 to 160 mm, and more preferably 25 to 110 mm.
[0031]
Furthermore, it is preferable that the other fibers have a melting point higher by 10 ° C. or more than the melting point of the fusion component of the heat-fusible fiber so as not to be melted by heat when fusing the heat-fusible fiber. It is more preferable to have a melting point higher by at least ° C.
[0032]
The filter medium of the present invention is made of a nonwoven fabric in which the above-mentioned fibers are mixed, preferably uniformly mixed, and heat-fusible fibers are fused. In addition, since the filter medium of this invention can be comprised only from the above organic fibers and can be incinerated when the filter medium has reached the end of its useful life, it is also suitable for disposal.
[0033]
The thickness of the filter medium (that is, non-woven fabric) of the present invention is preferably 5 to 50 mm. If the thickness of the filter medium is less than 5 mm, a relatively rough space cannot be formed by the heat-fusible fiber, so that there is a tendency that the pressure loss is high and cannot be used for a long period of time. Even if it is dense or rough, there is a tendency to increase the number of parts that do not participate in filtration, and in the case of unit processing, the processing tends to be difficult, so the thickness is more preferably 5 to 25 mm. preferable. This thickness is 1cm in unit area²The value at 1 g load per unit.
[0034]
The surface density of the filter medium is 50 to 500 g / m.²Is preferred. Areal density is 50 g / m²If it is less than 1, the density of the fibers tends to be too low, and it tends to be difficult to collect fine dust, while 500 g / m.²If it exceeds 1, the density of the fiber becomes too high, and the dust tends to become clogged immediately due to coarse dust and cannot be used for a long time.²It is more preferable that
[0035]
Furthermore, the apparent density of the filter medium is 0.001 to 0.1 g / cm.³IsThere is a need. Apparent density is 0.001 g / cm³If it is less than 1, it tends to be difficult to collect fine dust, while 0.1 g / cm.³If it exceeds, the clogging will soon occur due to coarse dust, and there is a tendency that it cannot be used for a long time, so 0.01-0.05 g / cm³It is more preferable that
[0036]
Such a filter medium of the present invention can be manufactured, for example, as follows. First, as shown in FIG. 1, the heat-fusible fiber 4 opened by the fiber spreader 3 with respect to the flow of the ultrafine fiber 2 discharged from the melt blow apparatus 1 under the above-described conditions (in some cases, other fibers) And the both are mixed, and the mixed fiber is collected by a collecting body 5 such as a conveyor to form a fiber web 6. Next, this fiber web 6 isBy heat treatment that does not substantially pressurizeOnly the heat-fusible fiber 4 can be fused by heat treatment to produce the nonwoven fabric 8 of the present invention, that is, the filter medium.
[0037]
Examples of the spreader 3 that supplies the heat-fusible fiber 4 include a card machine and a garnet machine, but a spreader 3 that houses a plurality of spreader cylinders 31 as shown in FIG. The heat-fusible fiber 4 can collide with the flow of the ultrafine fiber 2 vigorously and can be mixed with the ultrafine fiber 2 evenly in the thickness direction of the fiber web 6. it can. In addition, the spreader 3 can evenly spread even a fiber having a fiber length of about 25 to 110 mm which is suitable in the present invention.
[0038]
Moreover, when supplying the heat-fusible fiber 4 with the fiber spreader 3, it is preferable to supply from the direction as perpendicular as possible with respect to the flow of the ultrafine fiber 2 so that it can mix with the ultrafine fiber 2 more uniformly. For example, when the flow of the ultrafine fiber 2 discharged from the melt blow apparatus 1 is formed in the horizontal direction, the heat-fusible fiber 4 may be naturally dropped and supplied from above the flow of the ultrafine fiber 2. Although the flow of the ultrafine fiber 2 discharged from the melt blow apparatus 1 is generally the same as the direction in which the gravity works, the heat-fusible fiber 4 supplied from the fiber opening machine 3 is generally in the direction in which the gravity works. It is preferable to supply from a perpendicular direction. In the fiber opening machine 3 of FIG. 2, the air nozzle 33 which can supply air is provided so that the heat-fusible fiber 4 can be supplied at such an angle.
[0039]
In addition, by adjusting the angle at which the heat-fusible fiber 4 is supplied to the ultrafine fiber 2, the abundance ratio of the heat-fusible fiber 4 in the thickness direction of the fiber web 6 is changed, and the density is increased and decreased in the thickness direction. A structure can also be formed.
[0040]
The collector 5 that collects the fiber web 6 in which the ultrafine fibers 2 and the heat-fusible fibers 4 are mixed may be in a roll shape or in a net shape. The collector 5 is preferably air-permeable so that the fiber web 6 is not disturbed or scattered due to a collision with the flowing air, and a device capable of sucking and removing the air flow is provided on the side opposite to the collecting surface. preferable.
[0041]
The heat treatment in the present invention is carried out at a temperature not lower than the melting point of the fusion component of the heat-fusible fiber 4 and lower than the melting point of the ultrafine fiber 2 (including other fibers in some cases) in a substantially non-pressurized state. ProcessThere is a need.By doing so, the ultrafine fiber 2 is not formed into a film, can exhibit its original collection performance, and is a relatively rough space formed by heat-fusible fibers.That is, the apparent density is 0.001 to 0.1 g / cm as described above. ³ Filter media structureIs not impaired, and the pressure loss does not increase, so that the filter medium 8 that can be used for a long time can be manufactured. Further, the bulky filter material 8 can be manufactured in which the fusion is not biased to the vicinity of the surface of the filter material 8 and the filter material 8 is firmly fused even inside the filter material 8.
[0042]
Examples of the heat treatment apparatus 7 that can perform such heat treatment include a hot air circulation dryer and a suction air through dryer. For example, when the ultrafine fiber is made of polypropylene resin and the fusion component of the heat-fusible fiber is made of polyethylene resin, it is preferable to fuse the heat treatment apparatus 7 by setting the atmospheric temperature to 140 to 150 ° C.
[0043]
In addition, in order to adjust the thickness of the filter medium after this heat treatment, it may be passed between rolls or between flat plate presses at a temperature lower than the melting point of any fiber constituting the filter medium 8. Moreover, in order to raise collection efficiency more, you may implement an electretization process after a fusion process. In addition, when electret-ized, in order to further increase the efficiency, it is preferable to reduce the fiber oil agent of the heat-fusible fiber as much as possible by washing with water or hot water.
[0044]
In addition, before or simultaneously with heat treatment, or after the fiber may be adhered to each other with an adhesive such as an emulsion or latex, because the filtration performance may be reduced by a film formed by these adhesives, In many cases, these adhesives do not adhere. In addition, you may make it intertwined with a needle | hook or a fluid flow before or after heat processing.
[0045]
In the filter of the present invention, the filtration surface of the filter medium is disposed at an angle of 90 ° or not at an angle of 90 ° with respect to the inflow direction of the processing fluid. Since the former filter uses the above-mentioned filter medium, it can collect from coarse dust to fine dust in a narrow space, and can be used for a long time. The latter filter is also used for the above-mentioned filter medium. Therefore, it is possible to collect from coarse dust to fine dust, and it can be used for a longer period of time because of lower pressure loss.
[0046]
The “filter surface” of the filter medium is a surface perpendicular to the thickness direction of the filter medium and on the inflow side of the processing fluid. Further, “the filtration surface is arranged at an angle of 90 ° with respect to the inflow direction of the processing fluid” means that the filtration surface (hereinafter the same) is assumed to be a straight line and a smooth plane indicating the inflow direction of the processing fluid. This means that 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 90 °. ”Arranged at an angle other than 90 °” means that the angle between the straight line indicating the inflow direction of the processing fluid and the vertical direction of the filtration surface is not 90 °, or the straight line indicating the inflow direction of the processing fluid and the side of the filtration surface. This means that the angle formed with the direction is not 90 °, or any angle is not 90 °.
[0047]
More specifically, as shown in FIG. 3, the former filter is obtained by fixing the above-mentioned filter medium 8 with a frame material 9 in a flat shape, and the latter filter is as described above with reference to FIG. One in which one or more filter media 8 formed into a bag shape are fixed with a frame material 9, or the above-mentioned filter material 8 folded in a zigzag shape is fixed with a frame material 9 as shown in FIG. and so on.
[0048]
In addition, as the frame material 9, what consists of aluminum, aluminum alloy, stainless steel, or various resin can be used, for example. Moreover, fixing of the filter media 8 as shown in FIGS. 4 and 5 can be performed by heat sealing or sewing. Further, the filtering material 8 and the frame material 9 can be integrated by, for example, interposing a thermoplastic hot melt resin such as polyvinyl acetate between the frame material 9 and the filtering material 8.
[0049]
Examples of the present invention will be described below, but the present invention is not limited to the following examples.
[0050]
【Example】
Example 1
Nozzle pieces arranged with an orifice diameter of 0.2 mm and a pitch of 0.8 mm were heated to a temperature of 320 ° C., and polypropylene fibers were discharged at a rate of 0.04 g / min per orifice. A flow of ultrafine fibers 2 having an average fiber diameter of 1.5 μm was formed in the same direction as the direction of gravity by applying air having a temperature of 340 ° C. and a mass ratio of 75 times to the discharged polypropylene fibers.
[0051]
Two opening cylinders 31 as shown in FIG. 2 are accommodated in a housing 32 at right angles to the flow of the ultrafine fibers 2, and the core component is made of polypropylene resin (melting point) from the opening machine 3 provided with an air nozzle 33. 160 ° C.), the sheath component is made of polyethylene resin (melting point: 135 ° C.), the fiber diameter is 31 μm, the fiber length is 102 mm, the stretched core-sheath type fusible fiber is 70 mass%, and the core component is polypropylene resin (melting point: 160 ) And a sheath component made of polyethylene resin (melting point: 135 ° C.), with a fiber diameter of 52 μm and a fiber length of 102 mm, stretched core-sheath type heat-fusible fiber 30 mass% is supplied and mixed with polypropylene ultrafine fiber 2 did. The mixed fibers were collected by a mesh conveyor to form a fiber web 6. In addition, air was sucked and removed from the side opposite to the collecting surface of the conveyor to prevent the fiber web 6 from being disturbed.
[0052]
Next, the fiber web 6 is passed through a dryer at a temperature of 145 ° C. for 3 minutes to fuse only the sheath component (polyethylene component) of the core-sheath type heat-fusible fiber, and the surface density is 250 g / m.², Thickness 25mm, apparent density 0.01g / cm^ThreeThe filter material 8 was manufactured. In addition, this filtering material 8 is 50 g / m of polypropylene extra fine fiber 2.²(20 mass%) and 200 g / m of core-sheath type heat-fusible fiber²(80 mass%). The pressure loss at a surface speed of 50 cm / s of the filter medium 8 was measured by a pressure loss measuring machine (type 1) specified in JIS B 9908, and found to be 115 Pa. Moreover, the collection efficiency with respect to 0.3 μm atmospheric dust was 29%, and the collection efficiency with respect to 1 μm atmospheric dust was 91%.
[0053]
(Example 2)
Nozzle pieces arranged with an orifice diameter of 0.2 mm and a pitch of 0.8 mm were heated to a temperature of 340 ° C., and polypropylene fibers were discharged at a rate of 0.07 g / min per orifice. A 40-fold amount of air was applied to the discharged polypropylene fiber at a temperature of 360 ° C. and a mass ratio to form a flow of ultrafine fibers 2 having an average fiber diameter of 1.5 μm in the same direction as the direction of gravity. Next, a core-sheath type heat-fusible fiber 4 having exactly the same composition as in Example 1 was supplied in the same manner at right angles to the flow of the ultrafine fiber 2 to form a fiber web 6.
[0054]
Subsequently, 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 surface density was 220 g / m.², Thickness 10mm, apparent density 0.022g / cm^ThreeThe filter material 8 was manufactured. In addition, this filter material 8 is 100 g / m of polypropylene extra fine fiber 2.²(45.5 mass%) and 120 g / m of core-sheath type heat-fusible fiber.²(54.5 mass%). The pressure loss of the filter medium 8 at a surface speed of 10 cm / s was measured by a pressure loss measuring machine (Type 1) specified in JIS B 9908, and found to be 92 Pa. Further, the collection efficiency for 0.3 μm atmospheric dust was 75%, and the collection efficiency for 1 μm atmospheric dust was 99%.
[0055]
(Comparative example)
Nozzle pieces arranged with an orifice diameter of 0.2 mm and a pitch of 0.8 mm were heated to a temperature of 340 ° C., and polypropylene fibers were discharged at a rate of 0.07 g / min per orifice. A 40-fold amount of air was applied to the discharged polypropylene fiber at a temperature of 360 ° C. and a mass ratio to form a flow of ultrafine fibers 2 having an average fiber diameter of 1.5 μm in the same direction as the direction of gravity. Next, a core-sheath type heat-fusible fiber 4 having exactly the same composition as in Example 1 was supplied in the same manner at right angles to the flow of the ultrafine fiber 2 to form a fiber web 6.
[0056]
Subsequently, 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 surface density was 220 g / m.², Thickness 10mm, apparent density 0.022g / cm^ThreeThe filter material 8 was manufactured. In addition, this filter material 8 is 140 g / m of polypropylene extra fine fiber 2.²(63.6 mass%) and 80 g / m of core-sheath type heat-fusible fiber²(36.4 mass%). The pressure loss at a surface speed of 10 cm / s of the filter medium 8 was measured with a pressure loss measuring machine (Type 1) specified in JIS B 9908, and found to be 135 Pa. Moreover, the collection efficiency with respect to 0.3 μm atmospheric dust was 85%, and the collection efficiency with respect to 1 μm atmospheric dust was 99.5%.
[0057]
【The invention's effect】
The filter medium of the present invention is produced by a melt blow method, with an average fiber diameter of 0.1 to 10 μm of ultrafine fibers of 5 mass% or more and less than 50 mass%, and an average fiber diameter of 10 to 100 μm heat-fusible fibers of 50 mass% or more and 95 mass%. % Or less, and this heat-fusible fiberBy heat treatment that does not substantially pressurizeFrom a fused non-woven fabricAnd an apparent density of 0.001 to 0.1 g / cm ³ InThe Thus, the filter medium of the present invention has an average fiber diameter of 10 to 100 μm and is mainly composed of rigid heat-fusible fibers.Corresponds to the apparent density mentioned aboveSince a relatively coarse space is formed, coarse dust can be collected and the pressure loss can be reduced, so that it can be used for a long time. Moreover, since fine fibers having an average fiber diameter of 0.1 to 10 μm produced by the melt blow method are mixed in addition to the heat-fusible fibers, fine dust can also be collected. Therefore, the filter medium of the present invention can collect from coarse dust to fine dust with a single filter medium and can be used for a long time.
[0058]
In one of the filters of the present invention, the filtration surface of the filter medium is disposed at an angle of 90 ° with respect to the inflow direction of the processing fluid. Therefore, it is a filter that can collect from coarse dust to fine dust in a narrow space and can be used for a long time.
[0059]
In another filter of the present invention, the filtration surface of the filter medium is disposed at an angle other than 90 ° with respect to the inflow direction of the processing fluid. Therefore, the filter can be used for a longer period because of lower pressure loss.
[Brief description of the drawings]
FIG. 1 is a process diagram showing an example of a filter material manufacturing process
FIG. 2 is a schematic cross-sectional view of an example of a spreader
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 still another filter.
[Explanation of symbols]
1 Melt blow equipment
2 Extra fine fiber
3 Opening machine
31 Opening cylinder
32 Housing
33 Air nozzle
4 heat-fusible fiber
5 collector
6 Fiber web
7 Heat treatment equipment
8 Nonwoven fabric (filter material)
9 Frame material

Claims (4)

5 mass% or more and less than 50 mass% of ultrafine fibers having an average fiber diameter of 0.1 to 10 μm produced by the melt blow method and 50 mass% or more and 95 mass% or less of heat-fusible fibers having an average fiber diameter of 10 to 100 μm are mixed. , filtered to the heat-fusible fibers, Ri Do a nonwoven fabric was fused by a substantially pressureless heat treatment, and apparent density, characterized in that a 0.001 to 0.1 g / cm ³ Wood. The thickness of the nonwoven fabric is 5 to 50 mm, wherein the surface density of the nonwoven fabric is 50 to 500 g / ^{m 2,} claim 1 filtration material according.   The filter according to claim 1 or 2, wherein the filter surface is disposed at an angle of 90 ° with respect to the inflow direction of the processing fluid.   The filter according to claim 1 or 2, wherein the filter surface is disposed at an angle other than 90 ° with respect to the inflow direction of the processing fluid.

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