JP2001321620A - Cylindrical filter - Google Patents

Abstract

(57) [Problem] To provide a cylindrical filter which has a long filtration life and can be manufactured with good workability. SOLUTION: The cylindrical filter of the present invention comprises a main filtration nonwoven fabric made of a melt-blown nonwoven fabric, an auxiliary filtration nonwoven fabric having a larger average flow pore size than the main filtration nonwoven fabric, and a mixture of meltblown fibers and thermoplastic stretched fibers. Or, the average flow pore size is larger than the main filtration nonwoven fabric, substantially non-fibrillated, is a wet nonwoven fabric manufactured from fibers having a fiber diameter of less than 20 μm, and as the fibers, ultrafine fibers having a fiber diameter of 4 μm or less, Fiber diameter is 8μm or more, 20
an auxiliary filter non-woven fabric comprising a wet non-woven fabric having a bonded pore size of less than μm and a maximum pore size of not more than twice the average flow pore size, wherein the main filter non-woven fabric and the auxiliary filter non-woven fabric are adjacently laminated. In this state, it is arranged around the perforated cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical filter capable of filtering solids in a fluid, and more particularly to a cylindrical filter capable of filtering solids in a liquid.

[0002]

2. Description of the Related Art As a filter capable of filtering solids in a liquid, a so-called pleated filter in which a pleated filter material is arranged around a perforated cylinder has been known. This pleated filter is a suitable filter because of its large filtration area and long filtration life. As a filter material constituting the pleated filter, a nonwoven fabric obtained by subjecting a melt-blown nonwoven fabric to pressure treatment with a hot calender roll is known. Since this filter medium has a fine pore diameter, a desired filtration efficiency can be obtained. However, there is a problem that clogging is apt to occur due to poor fluid permeability and the filtration life is short. In addition, since this filter medium has no strength, there is a problem that foldability is poor. In order to improve the fold-folding property, a filter material in which a net is laminated on a melt-blown nonwoven fabric is known. Although the filter material on which the net is laminated improves the foldability, the net may damage the filter material (melt-blown nonwoven fabric). Further, since the net hardly contributes to filtration, it was not sufficiently satisfactory in terms of filtration life. Such a problem was sometimes found in the case of a so-called depth filter in which a filtering material was wound in a flat wound shape around a perforated cylinder.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a cylindrical filter which has a long filtration life and can be manufactured with good workability.

[0004]

Means for Solving the Problems One cylindrical filter of the present invention (hereinafter sometimes referred to as "first cylindrical filter").
Includes a main filtration nonwoven fabric made of a melt-blown nonwoven fabric, and an auxiliary filtration nonwoven fabric having a larger average flow pore diameter than the main filtration nonwoven fabric, and a mixture of meltblown fibers and thermoplastic drawn fibers. The filter nonwoven fabric is disposed around the perforated cylinder in a state of being adjacently laminated. The inventors of the present invention have conducted intensive studies,
When the main filtration nonwoven fabric made of the melt-blown nonwoven fabric is combined with a specific auxiliary filtration nonwoven fabric having a larger average flow pore diameter than the main filtration nonwoven fabric, that is, an auxiliary filtration nonwoven fabric in which melt-blown fibers and thermoplastic drawn fibers are mixed, a melt-blown nonwoven fabric is formed. It has been found that the filtration life is prolonged without impairing the filtration accuracy of the main filtration nonwoven fabric composed of. In addition, since the auxiliary filtered nonwoven fabric contains a thermoplastic stretched fiber and is excellent in strength, it is also found that the auxiliary filtered nonwoven fabric is excellent in processability (for example, fold folding processability, winding property). It was.

[0005] Another cylindrical filter of the present invention (hereinafter sometimes referred to as a "second cylindrical filter") comprises a main filtration nonwoven fabric made of a melt-blown nonwoven fabric and an average flow pore size larger than the main filtration nonwoven fabric. Not fibrillated,
A wet nonwoven fabric produced from fibers having a fiber diameter of less than 20 μm, wherein the fibers include ultrafine fibers having a fiber diameter of 4 μm or less and bonded adhesive fibers having a fiber diameter of 8 μm or more and less than 20 μm, and have a maximum pore diameter. Includes an auxiliary filtration nonwoven fabric made of a wet nonwoven fabric having a diameter equal to or less than twice the average flow pore size, wherein the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are arranged adjacent to each other and arranged around a perforated cylinder. is there.
The inventors of the present invention have conducted intensive studies and found that a main filtration nonwoven fabric composed of a melt-blown nonwoven fabric, a specific auxiliary filtration nonwoven fabric having a larger average flow pore size than this main filtration nonwoven fabric, that is,
It is a wet nonwoven fabric produced from fibers that are not substantially fibrillated and have a fiber diameter of less than 20 μm, wherein the fibers are ultrafine fibers having a fiber diameter of 4 μm or less, and a fiber diameter of 8 μm.
As described above, when combined with an auxiliary filtration non-woven fabric comprising a wet non-woven fabric having a bonded pore size of less than 20 μm and having a maximum pore size of not more than twice the average flow pore size, the filtration accuracy of the main filtration non-woven fabric composed of a melt blown non-woven fabric is impaired. And found that the filtration life was prolonged. In addition, since the above-mentioned auxiliary filtration nonwoven fabric contains bonded adhesive fibers and is excellent in strength, it is also found that it is excellent in workability (for example, foldability, winding property). It was.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Each of the main nonwoven fabrics constituting the first tubular filter and the second tubular filter of the present invention comprises a melt-blown nonwoven fabric. Since this melt-blown nonwoven fabric is made of melt-blown fibers that have not been subjected to a strong drawing action, the average flow pore size can be easily adjusted by performing the heat treatment and the pressure treatment. Can be easily handled. The average flow pore size of the main filtration nonwoven fabric is not particularly limited since it varies depending on the fluid to be filtered and the like, but is preferably about 0.5 to 40 μm.
More preferably, it is about 5 to 20 μm. The “average flow pore size” in the present invention refers to a value obtained by a method specified in ASTM-F316, and includes, for example, a porometer and a Coulter.
r) (manufactured by R) Co., Ltd.). This `` melt blow non-woven fabric '' refers to a non-woven fabric manufactured by a melt blow method, for example,
Orifice diameter 0.1 ~ 0.5mm, pitch 0.3 ~
A nozzle piece having an orifice arranged at 1.2 mm is heated to a temperature of 220 to 370 ° C., and a resin is discharged at a rate of 0.02 to 1.5 g / min per one orifice. After forming a melt blown fiber by applying a gas at a temperature of 220 to 400 ° C. and a mass ratio of 5 to 2,000 times the amount of the resin discharged, it is collected and manufactured by a collecting body such as a roll or a conveyor. it can.
The melt blown fibers can be composed of a thermoplastic resin, for example, a polyester resin, a polyamide resin, a polyolefin resin (for example, a polyethylene resin or a polypropylene resin), a polyvinylidene chloride resin, a polyvinyl chloride. It can be composed of at least one kind of resin such as resin, polystyrene resin, polyacrylonitrile resin, and polyvinyl alcohol resin. Among these resins, polyolefin-based resins (particularly, polypropylene) are preferable because they have excellent chemical resistance and excellent versatility. In addition, the resin component constituting the melt blown fiber does not need to be one kind, and may include two or more kinds. When the meltblown fiber is composed of two types of resin components, the cross-sectional shape can be, for example, a core-sheath type, an eccentric type, a side-by-side type, a sea-island type, an orange type, or a multi-bimetal type. This melt blown nonwoven fabric may be used as it is by collecting and accumulating the melt blown fibers discharged from the orifice by a collector,
In order to adjust the average flow hole diameter, a material subjected to heat treatment and / or pressure treatment after accumulation may be used. When performing the heat treatment and the pressure treatment, the heat treatment and the pressure treatment may be performed simultaneously, or the pressure treatment may be performed after the heat treatment. In either case, the heating temperature is 5 to 120 ° C. lower than the melting point of the meltblown fiber (when the meltblown fiber is composed of two or more thermoplastic resins having different melting points, the resin having the lowest melting point). Is preferable, and the linear pressure is 0.3 in each case.
３3 kN / cm is preferred. The “melting point” in the present invention refers to a temperature at which a maximum value of a melting endothermic curve obtained by raising the temperature from room temperature using a differential scanning calorimeter at a temperature rise rate of 10 ° C./min is used. When there are two or more maximum values, the maximum value at the highest temperature is defined as the melting point. The areal density of the melt blown nonwoven fabric of the present invention is preferably about ²⁰ to 200 g / m ² , the thickness is preferably about 0.03 to 1 mm, and the apparent density is 0.2 to 0.6 g / cm 2. ^It is preferably about ³ .

[0007] In the case of the first tubular filter of the present invention, the auxiliary filtration nonwoven fabric (hereinafter, referred to as "first filtration filter") having a larger average flow pore size than the above-mentioned main filtration nonwoven fabric and having a mixture of melt blown fibers and thermoplastic drawn fibers. 1) may be in a state of being laminated adjacent to the main filtration nonwoven fabric as described above. Since the first auxiliary filtered nonwoven fabric contains the meltblown fiber manufactured by the meltblown method, the filtration accuracy is high, and since it contains the thermoplastic stretched fiber, it is possible to maintain an appropriate gap,
The filtration flow rate can be increased. Furthermore, since it contains thermoplastic stretched fibers, it has strength and can improve processability. The average fiber diameter (average fiber diameter at 100 or more points) of the melt blown fibers constituting the first auxiliary filtered nonwoven fabric is preferably from 0.1 to 20 μm, more preferably from 0.1 to 10 μm. preferable. Further, such a melt blown fiber is preferably contained in the first auxiliary filtered nonwoven fabric in an amount of 5 to 95 mass%, preferably 1 to 95 mass%.
More preferably, the content is 5 to 85 mass%. The "fiber diameter" in the present invention refers to the diameter of the fiber when the cross-sectional shape of the fiber is circular, and the diameter when converted to a circular cross-section when the cross-sectional shape of the fiber is non-circular. Say. The conditions for producing meltblown fibers by this meltblown method are not particularly limited, for example,
It can be manufactured under the following conditions. A nozzle piece having an orifice diameter of 0.1 to 0.5 mm and an orifice arranged at a pitch of 0.3 to 1.2 mm is heated to a temperature of 220 to 37.
Heat to 0 ° C and apply 0.02-1.
Resin is discharged at a rate of 5 g / min, and the discharged resin is reacted with a gas having a temperature of 220 to 400 ° C. and a mass ratio of 5 to 2,000 times the fiber discharge amount to produce the resin. it can. The resin component constituting the melt blown fiber may be a thermoplastic resin, and may be exactly the same as the resin constituting the melt blown fiber constituting the above-mentioned main filtration nonwoven fabric. For the same reason, a polyolefin resin (particularly, (Polypropylene). It should be noted that the resin component constituting the melt blown fiber does not need to be one kind, but may include two or more kinds. When the meltblown fibers are made of two or more types of resins, the cross-sectional shape can be, for example, a core-sheath type, an eccentric type, a side-by-side type, a sea-island type, an orange type, or a multi-bimetal type. On the other hand, `` thermoplastic drawn fiber '' is not a fiber drawn by applying air to the fiber extruded from a nozzle, such as melt blown fiber or spunbond fiber, but a fiber extruded from a nozzle by a drawing machine or the like. Fiber drawn by mechanical action. The average fiber diameter of the thermoplastic stretched fiber is preferably from 10 to 100 μm, more preferably from 15 to 80 μm. Further, such a thermoplastic stretched fiber is preferably contained in the first auxiliary filtered nonwoven fabric in an amount of 5 to 95 mass%, preferably 1 to 95 mass%.
More preferably, the content is 5 to 85 mass%. Incidentally, the average fiber diameter of the thermoplastic stretched fiber, when the thermoplastic stretched fiber is a long fiber, refers to the average value of the fiber diameter at 100 or more points, when the thermoplastic stretched fiber is a short fiber Means the average value of the fiber diameters of 100 or more thermoplastic drawn fibers. The thermoplastic stretched fiber can be composed of one or more resins similar to the thermoplastic resin constituting the melt blown fiber as described above. When the thermoplastic stretched fiber is composed of two or more resins, the cross-sectional shape thereof can be, for example, a core-sheath type, an eccentric type, a side-by-side type, a sea-island type, an orange type, or a multiple bimetal type. When the thermoplastic stretched fiber is made of two or more kinds of resins as described above, the fiber shape can be maintained by the non-adhesive resin component (non-adhesive component) even if the adherable resin component (adhesive component) is adhered. Since an appropriate space of the thermoplastic drawn fiber can be maintained, fluid permeability is excellent. In this case, the difference in melting point between the adhesive component and the non-adhesive component is preferably at least 10 ° C, more preferably at least 20 ° C. The adhesive component of the thermoplastic stretched fiber is preferably at least 10 ° C. lower than the melting point of the meltblown fiber (if the meltblown fiber is composed of two or more resins, the melting point of the resin having the lowest melting point).
It is more preferable that the temperature is lower than or equal to ° C. The thermoplastic drawn 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 meltblown fiber. In the case of a short fiber, 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 melt blown fiber. The thermoplastic stretched fiber does not need to consist of one kind, and two or more kinds of thermoplastic stretched fibers differing in fiber diameter, composition, fiber length and the like may be used in combination. Such a first auxiliary filtered nonwoven fabric can be manufactured, for example, as follows. First, as shown in FIG. 1, a thermoplastic stretched fiber 4 opened by a spreader 3 is supplied to a flow of a melt blown fiber 2 formed by a melt blow apparatus 1 under the above-described conditions, and both are supplied. After mixing, the mixed fiber group can be collected by a collector 5 such as a conveyor to form a first auxiliary filtered nonwoven fabric 6. Examples of the spreader 3 that supplies the thermoplastic stretched fiber 4 include a card machine and a garnet machine, and the spreader 3 in which a plurality of spread cylinders 31 are housed in a housing 32 as shown in FIG. The thermoplastic stretched fibers 4 can be made to collide with the flow of the melt blown fibers 2 vigorously to uniformly mix the melt blown fibers 2 and the thermoplastic stretched fibers 4 even in the thickness direction of the first auxiliary filtered nonwoven fabric 6. Therefore, it is suitable. When the thermoplastic stretched fiber 4 is supplied by the opening device 3, the thermoplastic stretched fiber 4 is thermoplastically drawn from a direction perpendicular to the flow of the meltblown fiber 2 so that the thermoplastic stretched fiber 4 can be uniformly mixed with the meltblown fiber 2. Preferably, fibers 4 are provided. For example, when the flow of the meltblown fiber 2 formed by the meltblown apparatus 1 is in the horizontal direction, the thermoplastic stretched fiber 4 may be naturally dropped from above in the direction perpendicular to the flow of the meltblown fiber 2 and supplied. Although good, it is generally preferable that the flow direction of the melt-blown fibers 2 formed by the melt-blowing apparatus 1 is the same as the direction in which gravity acts. It is preferred to feed from a direction perpendicular to the direction of action. The spreader 3 shown in FIG. 2 is provided with an air nozzle 33 that can supply air so that the thermoplastic stretched fiber 4 can be supplied vigorously even at such an angle (right angle). By adjusting the angle at which the thermoplastic stretched fibers 4 are supplied to the melt blown fibers 2, the ratio of the thermoplastic stretched fibers 4 in the thickness direction of the first auxiliary filtered nonwoven fabric 6 can be changed. The collector 5 for collecting the fiber group in which the meltblown fiber 2 and the thermoplastic stretched fiber 4 are mixed may be in a roll shape or a conveyor shape. The collecting body 5 is preferably air-permeable so that the first auxiliary filter nonwoven fabric 6 is not disturbed or scattered by collision with the flowing air flow, and an air flow suction device is provided on the side opposite to the collecting surface. Is preferred. The first auxiliary filtered nonwoven fabric thus manufactured may be used as it is, but it is preferable to adjust the average flow pore size by performing a heat treatment and / or a pressure treatment. The heat treatment and the pressure treatment may be performed simultaneously, or the pressure treatment may be performed after the heat treatment. The heating temperature when performing the heat treatment and the pressure treatment at the same time,
The temperature is preferably 5 to 120 ° C. lower than the melting point of the adhesive component of the thermoplastic stretched fiber.
４4 kN / cm is preferred. On the other hand, when the pressure treatment is performed after the heat treatment, the heating temperature is preferably 5 to 40 ° C. higher than the melting point of the adhesive component of the thermoplastic stretched fiber. 1-4
It is preferably kN / cm. The heating temperature when only the heat treatment is performed is preferably a temperature 5 to 40 ° C. higher than the melting point of the adhesive component of the thermoplastic stretched fiber.
The first auxiliary filtered nonwoven fabric in the first tubular filter of the present invention is a mixture of melt blown fibers and thermoplastic stretched fibers, and the average flow pore size is larger than the average flow pore size of the main filtered nonwoven fabric. is there. Therefore, a large solid substance is filtered by the first auxiliary filtration nonwoven fabric, and the load on the main filtration nonwoven fabric is reduced, thereby extending the filtration life of the main filtration nonwoven fabric. In addition, the first auxiliary non-woven filter fabric prevents the main non-woven filter fabric from adhering to each other, so that the main non-woven filter fabric can sufficiently exhibit its filtration performance.
Since the size of the average flow pore size of the first auxiliary filtration nonwoven fabric changes as appropriate depending on the fluid to be filtered,
Although not particularly limited, the average flow pore size of the first auxiliary filtration nonwoven fabric is 2 to 4 times larger than the average flow pore size of the main filtration nonwoven fabric.
It is preferably about 0 μm, more preferably about 2 to 20 μm. That is, as described above, the average flow pore size of the main filtration nonwoven fabric is preferably about 0.5 to 40 μm, and more preferably about 0.5 to 20 μm. 2.5-8
It is preferably about 0 μm, more preferably about 2.5 to 60 μm, and still more preferably about 2.5 to 40 μm. The areal density of the first auxiliary filtered nonwoven fabric of the present invention is preferably about 5 to 200 g / m ² , the thickness is preferably about 0.005 to ² mm, and the apparent density is 0.05 to 0. It is preferably about 7 g / cm ³ .

[0008] In the second tubular filter of the present invention, the main filter nonwoven fabric and the fibers having an average flow pore size larger than that of the main filter nonwoven fabric and having substantially no fibrillation and having a fiber diameter of less than 20 µm are used. A manufactured wet nonwoven fabric, wherein the fibers include ultrafine fibers having a fiber diameter of 4 μm or less, and bonded adhesive fibers having a fiber diameter of 8 μm or more and less than 20 μm, and a maximum pore diameter is twice the average flow pore diameter. An auxiliary filtered nonwoven fabric (hereinafter, sometimes referred to as “second auxiliary filtered nonwoven fabric”) made of the following wet nonwoven fabric is in a laminated state. Therefore, large solids are filtered by the second auxiliary non-woven fabric, and the load on the main non-woven fabric is reduced, so that the filtration life can be extended. Also,
The second auxiliary filter non-woven fabric can suppress the close contact between the main filter non-woven fabrics and sufficiently exhibit the filtration performance of the main filter non-woven fabric. Further, since the second auxiliary filter nonwoven fabric has a narrow pore size distribution, the filtration accuracy of the cylindrical filter can be further improved. Although the degree of the average flow pore size of the second auxiliary filtration nonwoven fabric is not particularly limited because it varies depending on the fluid to be filtered and the like, the average flow pore size of the second auxiliary filtration nonwoven fabric is the same as that of the main filtration nonwoven fabric. It is preferably about 2 to 40 μm larger than the average flow pore diameter,
More preferably, it is about 20 μm larger. That is, as described above, the average flow pore size of the main filtration nonwoven fabric is 0.5 to 40 μm.
The average flow pore size of the second auxiliary filtered nonwoven fabric is preferably about 2.5 to 80 μm, and more preferably about 0.5 to 20 μm.
It is more preferably about 5 to 60 μm, and 2.5 to 4 μm.
More preferably, it is about 0 μm. The areal density of the second auxiliary filtered nonwoven fabric of the present invention is preferably about 5 to 200 g / m2, the thickness is preferably about 0.005 to ² mm, and the apparent density is 0.05 to 0. It is preferably about 7 g / cm ³ . The second auxiliary filtered nonwoven fabric (wet nonwoven fabric) is manufactured from fibers that are not substantially fibrillated so as not to impair the uniform dispersibility of the fibers. This "non-fibrillated fiber"
A fiber in which a plurality of fibers are not bonded. For example, fibers in which a number of fibers are branched from one fiber (for example, fibers beaten by a beater, pulp, etc.), and a plurality of fibers are already bonded. And not in a network state (for example, a fiber obtained by a flash spinning method). The second auxiliary-filtered nonwoven fabric (wet-type nonwoven fabric) has a fiber diameter of less than 20 μm (preferably a fiber having a diameter of less than 20 μm so that the arrangement of the fibers is not disturbed by the mixture of the thick fibers so that a large opening diameter is not formed. , A fiber having a fiber diameter of 18 μm or less). More specifically, it includes ultrafine fibers having a fiber diameter of 4 μm or less and bonded adhesive fibers having a fiber diameter of 8 μm or more and less than 20 μm. The former ultrafine fibers have a fiber diameter of 4 μm or less, and more preferably 3 μm or less, so that a uniform pore diameter can be formed by uniformly dispersing the fibers. Although the lower limit of the fiber diameter of the ultrafine fiber is not particularly limited, it is not limited to 0.1.
It is preferably at least 1 μm, more preferably at least 0.3 μm, even more preferably at least 0.5 μm, most preferably at least 0.75 μm. It is preferable that the diameters of the ultrafine fibers are substantially the same so that a uniform pore diameter can be formed by the above-described ultrafine fibers.
That is, the value obtained by dividing the standard deviation value of the fiber diameter distribution of the ultrafine fibers by the average value of the fiber diameters of the ultrafine fibers is preferably 0.2 or less (preferably 0.18 or less). When the fiber diameters of the ultrafine fibers are all the same, the standard deviation is 0. Therefore, the lower limit of the value obtained by dividing the standard deviation of the fiber diameter distribution of the ultrafine fibers by the average value of the fiber diameters of the ultrafine fibers. Is 0. The "average fiber diameter" of the ultrafine fibers is obtained by taking an electron micrograph of the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) and measuring the fiber diameter of 100 or more (n) ultrafine fibers in the electron micrograph. And a value obtained by averaging the measured fiber diameters. The “standard deviation value” of the microfiber refers to a value calculated from the measured fiber diameter (χ) by the following formula. Standard deviation = {(nΣχ ² − (Σχ) ² ) / n (n−1)}
^1/2 where n means the number of the measured ultrafine fibers, and χ means the fiber diameter of each ultrafine fiber. The fiber diameter is 4
When there are two or more types of ultrafine fibers having a size of not more than μm, it is preferable that the above relationship is satisfied for each of the ultrafine fibers. Further, it is preferable that the ultrafine fibers have substantially the same diameter in the fiber axis direction of the ultrafine fibers so that a second auxiliary filtered nonwoven fabric (wet nonwoven fabric) having a uniform pore diameter can be formed. Such microfibers having substantially the same fiber diameter, or microfibers having substantially the same diameter in the fiber axis direction, for example, extrude the island component by spinning the sea component at the spinneret. It can be obtained by removing the sea component of the sea-island type fiber obtained by the compound spinning method for compounding. In addition, by removing the sea component of the sea-island type fiber obtained by a method of spinning after mixing the resin constituting the island component and the resin constituting the sea component, which is generally called a mixed spinning method, is substantially the same. It is difficult to obtain ultrafine fibers having a fiber diameter or ultrafine fibers having substantially the same diameter in the fiber axis direction. Although the resin constituting the ultrafine fiber is not particularly limited, for example, polyamide such as nylon 6, nylon 66, and nylon copolymer, polyethylene terephthalate, polyethylene terephthalate copolymer, polybutylene terephthalate, polybutylene Polyesters such as terephthalate copolymers, polyethylene, polypropylene, poly-4-
It can be composed of one or more kinds of synthetic resins such as polyolefin such as methyl-1-pentene and olefin-based copolymer, polystyrene, polyurethane, and vinyl polymer. In addition, when the ultrafine fiber contains a resin component capable of participating in adhesion (hereinafter, sometimes referred to as an “adhesive component”) and is adhered by this adhesive component, the ultrafine fiber can be reliably fixed, This is a preferred embodiment because it does not fall off or fluff. When bonding the ultrafine fibers, the ultrafine fibers can be composed of only the adhesive component composed of the resin as described above, or the adhesive component and a component having a melting point higher than the melting point of the adhesive component (hereinafter referred to as “non-adhesive”). Component)). When the ultrafine fibers are composed of two or more resin components including an adhesive component and a non-adhesive component as in the latter, the fiber form is maintained even when the ultrafine fibers are adhered, and the microfine fibers are the original function. This is more preferable because it does not hinder the formation of a uniform pore size. When the microfiber is composed of two or more types of resin components, the adhesive component occupies at least a part of the surface of the microfiber so that it can participate in bonding (the cross-sectional shape of the microfiber is, for example, a core-sheath type). , Eccentric type, side-by-side type, sea-island type, orange type, multiple bimetal type), and the entire surface of the microfiber (the cross-sectional shape of the microfiber is, for example, core-sheath type, eccentric type, sea-island type). ) Is more preferably occupied by an adhesive component. On the other hand, the non-adhesive component can maintain the fiber shape,
Preferably, it is higher than the melting point of the adhesive component by 10 ° C. or more.
It is more preferable that the temperature is higher than 0 ° C. The non-adhesive component preferably has a melting point higher by at least 10 ° C. than the melting point of the adhesive component of the adhesive fiber described below, so that the fiber shape can be maintained even by the heat at the time of bonding the adhesive fiber described below. 2
More preferably, it has a melting point higher than 0 ° C. The ultrafine fibers comprising two or more types of resin components including a suitable adhesive component and a non-adhesive component are used as a die for extruding island components when spinning by a conventional composite spinning method, and have a cross-sectional shape as described above. (For example, a core-sheath type, an eccentric type, a side-by-side type, a sea-island type, an orange type, a multi-bimetal type, etc.). it can. In addition, the ultrafine fiber may have properties such as crimping property and splitting property in addition to the adhesive property as described above. As the former ultra-fine fibers having crimp development, as the cross-sectional shape is an eccentric type or a side-by-side type, an ultra-fine fiber in which two or more types of resin components are arranged can be used. An ultrafine fiber having two or more types of resin components can be used, such as a sea-island type, an orange type or a multi-bimetal type. As described later, it is preferable that the ultrafine fibers are short fibers having a high degree of freedom (fiber length is 30 mm or less) so as to be easily dispersed uniformly. Since the same state as the fibrillated fiber is obtained when the members or the island components are pressed together, it is necessary to use the ultrafine fibers or the sea-island type fibers in which the ultrafine fibers or the island components are not easily pressed together when cutting. preferable. Examples of such ultrafine fibers or sea-island fibers that are difficult to press-bond include, for example, ultrafine fibers having high crystallinity (in the case of sea-island fibers, island components). More specifically,
When the ultrafine fiber (island component in the case of a sea-island type fiber) contains polymethylpentene or syndiotactic polystyrene, or contains polypropylene, the melting point of the polypropylene is 166 ° C. or more (preferably 168 ° C.).
Above), it is difficult to perform pressure bonding. On the other hand, the adhesive fiber is thicker than the ultrafine fiber and has a fiber diameter of 8 μm or more so that the ultrafine fiber is adhered to fix the ultrafine fiber and the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) can be given strength.
In order to prevent the arrangement of the ultrafine fibers from being disturbed by the adhesive fibers and to form a large opening diameter, the fiber diameter is set at 20.
It is less than μm. The more preferable fiber diameter of the adhesive fiber is 8
μm or more and 18 μm or less. The adhesive fiber may be composed of a single component, but is preferably composed of two or more resin components so that the fiber form is maintained and the strength is excellent even after bonding. As an arrangement state of the two or more resin components, for example, the fiber cross-sectional shape may be a core-sheath type, an eccentric type, a side-by-side type, a sea-island type, an orange type, a multiple bimetal type, or the like. Among these, a resin capable of participating in adhesion, that is, a core-sheath type, an eccentric type, or a sea-island type having a large amount of an adhesive component is preferable. This adhesive fiber can be composed of the same resin as the ultrafine fiber.However, when the ultrafine fiber is not bonded, the adhesive fiber is not melted by heat at the time of bonding the adhesive fiber. The melting point of the adhesive component is preferably at least 10 ° C. lower than the melting point of any resin component of the ultrafine fibers, and more preferably at least 20 ° C. lower. On the other hand, when the adhesive component of the ultrafine fiber is also bonded, the adhesive component of the adhesive fiber and the adhesive component of the ultrafine fiber are bonded so that the adhesive component of the adhesive fiber and the adhesive component of the ultrafine fiber can be simultaneously performed. Is preferably within 35 ° C., and 30 ° C.
More preferably, it is within the range. In addition, the melting point of the adhesive component of the adhesive fiber and the melting point of the adhesive component of the ultrafine fiber (when a plurality of types of ultrafine fibers are present, the melting point of the resin component having the melting point closest to the melting point of the adhesive component of the adhesive fiber) Is 1
When the temperature is 0 ° C. or more and 35 ° C. or less, the adhesive component of the ultrafine fibers can be bonded, or the ultrafine fibers can not be bonded. When the ultrafine fiber contains an adhesive component and a non-adhesive component, the melting point of the adhesive component of the adhesive fiber is 10 ° C. lower than the melting point of the non-adhesive component of the ultrafine fiber so that the ultrafine fiber can maintain the fiber shape. Or lower, preferably 2
It is more preferable that the temperature is lower than 0 ° C. Furthermore, if the adhesive fiber is 2
In the case where the adhesive fiber is composed of more than two kinds of resin components, a resin component other than the adhesive component (non-adhesive component) so that the adhesive fiber can maintain the fiber shape even by heat at the time of bonding the adhesive fiber.
Is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, than the melting point of the adhesive component. Such an adhesive fiber can be easily spun by a conventional composite spinning method or mixed spinning method. This second auxiliary filtered nonwoven fabric (wet nonwoven fabric)
Contains ultrafine fibers and adhesive fibers as described above.
The mass ratio of these fibers varies depending on the specific application and required physical properties of the tubular filter, etc. (ultrafine fibers):
(Adhesive fiber) = 30 to 70: 70 to 30 is preferable. When the amount of the ultrafine fibers is 30 mass% or more, a second auxiliary filtered nonwoven fabric (wet nonwoven fabric) having a narrow pore size distribution can be obtained. On the other hand, when the amount of the adhesive fibers is 30 mass% or more, the ultrafine fibers are sufficiently fixed. Therefore, the ultrafine fibers hardly fall off, and the wet nonwoven fabric can be given strength. A more preferable mass ratio is (ultrafine fiber) :( adhesive fiber) = 35 to 65:65 to 35. In addition, these mass ratios refer to the ratio to the whole mass of the second auxiliary filtration nonwoven fabric (wet nonwoven fabric). This second auxiliary filtered nonwoven fabric (wet nonwoven fabric) has a fiber diameter of more than 4 μm and 8 μm in addition to the aforementioned ultrafine fibers and adhesive fibers.
m (hereinafter sometimes referred to as “intermediate fiber diameter fiber”). The content of the intermediate fiber has a value of 40 from the relationship with the ultrafine fibers and the adhesive fibers.
It is preferably at most 30% by mass, more preferably at most 30% by mass. That is, (microfiber):
(Adhesive fiber): (intermediate fiber diameter fiber) = 30 to 70: 7
It is preferably 0 to 30: 0 to 40, and (ultrafine fiber) :( adhesive fiber) :( intermediate fiber diameter fiber) = 35 to 6
The ratio is more preferably from 5:65 to 35: 0 to 30. The fibers (for example, ultrafine fibers, adhesive fibers, and intermediate fiber diameter fibers) constituting the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) can be in an unstretched state. It is preferable that the fiber extruded from the nozzle is drawn by a mechanical action such as a drawing machine. The fiber length of the fibers (for example, ultrafine fibers, adhesive fibers, intermediate fiber diameter fibers, etc.) constituting the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) is not particularly limited. The fibers constituting the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) preferably have a fiber length of 0.5 to 30 mm, since it has a high degree of freedom and can be uniformly dispersed. Preferably, the fibers constituting the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) (eg, ultrafine fibers, adhesive fibers, intermediate fiber diameter fibers, etc.) have a fiber length of 0.5 to 30 mm.
Has been disconnected. The “fiber length” in the present invention is JIS L 1015 (chemical fiber staple test method) B
Length (corrected staple diagram method). This second auxiliary filtered nonwoven fabric (wet nonwoven fabric) is composed of the above-mentioned fibers, and has a narrow pore size distribution with a maximum pore size of twice or less (more preferably 1.9 times or less) the average flow pore size. . Ideally, the maximum pore size is one time the average flow pore size, that is, the total pore size is the same size.
This "maximum pore diameter" is determined by a porometer (Polometer,
It refers to a value measured by a bubble point method using a Coulter company. If the fibers (for example, ultrafine fibers, adhesive fibers, intermediate fiber diameter fibers, etc.) constituting the second auxiliary filtration nonwoven fabric (wet nonwoven fabric) are substantially two-dimensionally arranged, the arrangement of the fibers is regular. This is a preferred embodiment because the pore size distribution can be further narrowed by the above. In addition, "the fibers are substantially two-dimensionally arranged" means that the fibers oriented in the thickness direction are not substantially arranged, for example, for a fiber web formed by a wet method. This is a state that can be obtained in a case where the components are joined only by bonding without applying a fluid flow such as a water flow. Such a second auxiliary filtered nonwoven fabric (wet nonwoven fabric) can be manufactured, for example, as follows. First, it is virtually non-fibrillated,
At least an ultrafine fiber and an adhesive fiber are prepared. As the ultrafine fibers, those having substantially the same fiber diameter, that is, the value obtained by dividing the standard deviation value of the fiber diameter distribution of the ultrafine fibers by the average value of the fiber diameter of the ultrafine fibers is 0.2 or less (preferably 0.18 or less) , 0 or more), it becomes easy to produce an auxiliary filtered nonwoven fabric (wet nonwoven fabric) having a narrow pore size distribution. In addition, the fiber length of the ultrafine fiber or the adhesive fiber is 0.
It is preferably from 5 to 30 mm. In addition, when fibers (for example, ultrafine fibers) that are not easily pressed during cutting are used, the dispersibility of the fibers is improved, and the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) having a narrow pore size distribution is easily manufactured. Next, using these fibers, a fiber web is formed by a conventional wet method. Since the fibers used are not substantially fibrillated, the fibers can be uniformly dispersed in water as a dispersion bath, and since the fibers do not become entangled with the wire for making the fibers, the desired texture is excellent. The second auxiliary filtered nonwoven fabric (wet nonwoven fabric) can be manufactured. When forming this fiber web, a thickener may be added to maintain a uniform dispersion state of the fiber, or a surfactant may be added to increase the affinity between water and the fiber (particularly, the affinity with water). When a fiber made of a resin component having low water-repellency is used, when an antifoaming agent is added to remove air bubbles generated by stirring or the like, the dispersibility of the fiber is improved, and the second auxiliary filtered nonwoven fabric having a narrow pore size distribution (wet nonwoven fabric) ) Is easier to manufacture. Then, simultaneously with or after drying the fiber web, by applying heat (and pressure if necessary) to which the adhesive component of the adhesive fiber can adhere (the adhesive component of the ultrafine fiber can also adhere in some cases), By bonding the adhesive component of the adhesive fiber (and the adhesive component of the microfiber in some cases),
A second auxiliary filtered nonwoven fabric (wet nonwoven fabric) can be obtained. As described above, when the second auxiliary filtered nonwoven fabric (wet nonwoven fabric) is manufactured by adhering the adhesive component of the adhesive fiber (the adhesive component of the ultrafine fiber in some cases) without causing the fluid web such as the water stream to act on the fiber web, the fiber Are two-dimensionally arranged, so that it is easy to manufacture a second auxiliary filtered nonwoven fabric (wet nonwoven fabric) having a narrow pore size distribution.

[0009] The above-mentioned auxiliary filtered nonwoven fabric (first auxiliary filtered nonwoven fabric or second auxiliary filtered nonwoven fabric, hereinafter the same) is in a state of being laminated adjacent to the above-mentioned main filtered nonwoven fabric. This auxiliary filtered nonwoven fabric may be adjacent to only one surface of the main filtered nonwoven fabric, or may be adjacent to both surfaces. For example, in the case of a so-called depth-type cylindrical filter, it is sufficient that the auxiliary filtration non-woven fabric is adjacent to only one side of the main filtration non-woven fabric, and in the case of a so-called pleated cylindrical filter,
It is preferable that the auxiliary filtration nonwoven fabric is adjacent to both sides of the main filtration nonwoven fabric. In addition, when the auxiliary filtration nonwoven fabric is adjacent to both surfaces of the main filtration nonwoven fabric, the same auxiliary filtration nonwoven fabric may be adjacent in terms of the average flow pore size, or different auxiliary filtration nonwoven fabrics in terms of the average flow pore size. It may be adjacent. In addition, the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric may be in a bonded state or in a non-bonded state. As the former combined state, for example, heat treatment after laminating the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric,
Or, a state of bonding and integration by performing heat treatment and pressure treatment, a state of integration by ultrasonic treatment, a state of entanglement and integration by needle or fluid flow (preferably water flow), bonding and integration by adhesive State. Further, the auxiliary filtration nonwoven fabric to be laminated adjacent to the main filtration nonwoven fabric does not need to be one type, and two or more types of auxiliary filtration nonwoven fabrics may be laminated. When two or more types of auxiliary filtration nonwoven fabrics are laminated as described above, it is preferable that the auxiliary filtration nonwoven fabrics are sequentially laminated from the fluid inflow side to the fluid outflow side so as to have smaller average flow pore diameters. In addition, 2
When more than one type of auxiliary filter nonwoven fabrics are laminated, these auxiliary filter nonwoven fabrics may be in a bonded state or a non-bonded state. Examples of the state of bonding as the former include, for example, a state of being bonded and integrated by a heat treatment or a heat treatment and a pressure treatment, a state of being integrated by an ultrasonic treatment, and entanglement by a needle or a fluid flow (preferably a water flow). There are a state of being integrated and a state of being integrated by bonding with an adhesive.

[0010] The tubular filter of the present invention is a state in which the main filtration non-woven fabric and the auxiliary filtration non-woven fabric described above are laminated adjacent to each other,
It is arranged around the perforated cylinder. Examples of the arrangement state include a state in which a main filtration nonwoven fabric and an auxiliary filtration nonwoven fabric have a region wound around a perforated tube (so-called depth type), and a case where the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are folded. And a state having a region arranged around the perforated cylinder (so-called pleated type) or a state having both of these regions.

[0011] The former depth-type cylindrical filter has a region in which the main filtration non-woven fabric and the auxiliary filtration non-woven fabric are wound around the perforated cylinder, but the number of turns is not particularly limited. In addition, the number of turns of the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric may be the same or different. That is, the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric do not need to be adjacent to each other over the entire circumference, and may be adjacent to each other only in a part of the region. When the main filtration non-woven fabric and the auxiliary filtration non-woven fabric are adjacent only in a part of the region, it is preferable that the main filtration non-woven fabric and the auxiliary filtration non-woven fabric are adjacent on the outflow side of the processing fluid. That is, when the processing fluid flows in from the outside of the cylindrical filter and flows out to the inside,
The inner layer of the tubular filter preferably has a region where the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are wound adjacent to each other. Further, when the processing fluid flows in from the inside of the cylindrical filter and flows out, the main filter non-woven fabric and the auxiliary filter non-woven fabric are wound adjacent to each other in the outer layer of the cylindrical filter. Is preferred. The main filtration nonwoven fabric and / or the auxiliary filtration nonwoven fabric may be wound in any manner, may be wound in a flat winding shape, or may be wound in a spiral shape. Further, in the case of the depth type, the auxiliary filtration nonwoven fabric laminated adjacent to the main filtration nonwoven fabric does not need to be one type, and two or more types of auxiliary filtration nonwoven fabrics differing in average flow pore diameter are used as the main filtration nonwoven fabric. It is preferable that the layers are laminated so that the auxiliary filtration non-woven fabric having a larger average flow pore diameter is formed in order from the flow-in side to the fluid inflow side. By laminating the auxiliary filtration nonwoven fabric in this way, the filtration life can be further extended. More specifically, it is preferable that auxiliary filtration nonwoven fabrics having an average flow pore size larger by about 2 to 40 μm than the main filtration nonwoven fabric are sequentially laminated from the main filtration nonwoven fabric toward the fluid inflow side. In a region different from the region where the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are wound adjacent to each other,
The average flow pore size is 2 to 40 μm than the auxiliary filtration nonwoven fabric
It may have a region in which a coarsely-filtered fiber sheet of approximately large size is arranged in a wound or folded state. By having such a region where the coarsely-filtered fiber sheet is disposed, the filtration life can be further extended. The coarsely-filtered fiber sheet may be in a state of being bonded to the auxiliary-filtered nonwoven fabric or may be in a state of not being bonded. Examples of the combined state as the former include, for example, a state of being integrated by bonding at least by a heat treatment (preferably a heat treatment and a pressure treatment), a state of being integrated by an ultrasonic seal, a needle or a fluid flow (preferably a water flow). ), And a state of being integrated by bonding with an adhesive. The coarsely-filtered fiber sheet only needs to have a larger average flow pore size (about 2 to 40 μm) than the auxiliary filtered nonwoven fabric (when there are two or more types, the auxiliary filtered nonwoven fabric having the largest average flow pore size). Wet nonwoven fabric manufactured to have a large average flow pore size in the same manner as the filtered nonwoven fabric, nonwoven fabric in which melt blown fibers and thermoplastic stretched fibers manufactured to have a large average flow pore size in the same manner as the auxiliary filtered nonwoven fabric, mainly A melt blown nonwoven fabric manufactured to have a large average flow pore size in the same manner as the filtered nonwoven fabric, or a spun bond nonwoven fabric manufactured to have a large average flow pore size can be used. Further, in addition to the region where the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are wound, a region where the main filtration nonwoven fabric and / or the auxiliary filtration nonwoven fabric is arranged in a folded state may be provided.

[0012] Another cylindrical filter of the present invention is a pleated cylindrical filter having a region arranged around a perforated cylinder in a state where a main filtration nonwoven fabric and an auxiliary filtration nonwoven fabric are folded. The number of folds of the pleated cylindrical filter may be appropriately set depending on the application and required physical properties, and is not particularly limited. In this pleated cylindrical filter,
When the main filtration non-woven fabric and the auxiliary filtration non-woven fabric are folded and folded, not only may the surfaces of the main filtration non-woven fabric come into close contact with each other and reduce the filtration area, but also the back surfaces may adhere to each other and reduce the filtration area. Therefore, it is preferable that auxiliary filtration nonwoven fabrics are laminated on both sides of the main filtration nonwoven fabric. When the auxiliary filtration nonwoven fabric is laminated on both sides of the main filtration nonwoven fabric in this way, the auxiliary filtration nonwoven fabric having the same average flow pore size may be laminated on the front and back surfaces of the main filtration nonwoven fabric, or the auxiliary filtration nonwoven fabric having different average flow pore sizes may be used. The nonwoven fabric may be laminated on the front and back surfaces of the main filtration nonwoven fabric. Also, in the case of the pleated cylindrical filter, the auxiliary filtration nonwoven fabric laminated adjacent to the main filtration nonwoven fabric does not need to be one kind, and two or more types of auxiliary filtration nonwoven fabrics differing in average flow pore diameter are used. Alternatively, they may be laminated such that the auxiliary filter nonwoven fabric has a larger average flow pore diameter in order from the main filter nonwoven fabric to the fluid inflow side. By laminating the auxiliary filtration nonwoven fabric in this way, the filtration life can be further extended. More specifically, the average flow pore size is 2 to 40 μm in order from the main filtration nonwoven fabric to the fluid inflow side.
It is preferable that auxiliary filter nonwoven fabrics having a size of about m or more are laminated. When two or more types of auxiliary filtration nonwoven fabrics are laminated as described above, they may be laminated on both sides of the main filtration nonwoven fabric, or may be laminated on only one surface, but only on one side of the main filtration nonwoven fabric. Even when two or more types of nonwoven fabrics are laminated, it is preferable that one auxiliary filtration nonwoven fabric is laminated on the other surface of the main filtration nonwoven fabric in order to suppress the adhesion between the main filtration nonwoven fabrics. In the case where two or more types of auxiliary filtration nonwoven fabrics are laminated on only one side of the main filtration nonwoven fabric, the side where the two or more types of auxiliary filtration nonwoven fabrics are laminated is arranged so as to be the inflow side of the processing fluid. Is preferred. Note that, in a region different from the region where the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are arranged in a fold-folded state, the average flow pore size is 2 times larger than that of the auxiliary filtration nonwoven fabric.
You may have the area | region which wound the coarse filtration fiber sheet large about about 40 micrometers. When such a coarsely-filtered fiber sheet has a wound region, the filtration life can be further extended. The coarsely-filtered fiber sheet may be in a state of being bonded to the auxiliary-filtered nonwoven fabric or may be in a state of not being bonded. Examples of the combined state as the former include, for example, a state of being integrated by bonding at least by a heat treatment (preferably, a heat treatment and a pressure treatment), a state of being integrated by an ultrasonic seal, a needle or a fluid flow (preferably a water flow). ), And a state of being integrated by bonding with an adhesive. The coarsely-filtered fiber sheet only needs to have a larger average flow pore size (about 2 to 40 μm) than the auxiliary filtered nonwoven fabric (when there are two or more types, the auxiliary filtered nonwoven fabric having the largest average flow pore size). Wet nonwoven fabric manufactured to have a large average flow pore size in the same manner as the filtered nonwoven fabric, nonwoven fabric in which melt blown fibers and thermoplastic stretched fibers manufactured to have a large average flow pore size in the same manner as the auxiliary filtered nonwoven fabric, mainly A melt blown nonwoven fabric manufactured to have a large average flow pore size in the same manner as the filtered nonwoven fabric, or a spun bond nonwoven fabric manufactured to have a large average flow pore size can be used. Further, in addition to the region where the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are arranged in a folded state, the main filtration nonwoven fabric and / or the auxiliary filtration nonwoven fabric may have a wound region. The fold folding process can be performed by a fold folding machine, and the peak height, the peak interval, and the like can be appropriately set depending on the intended use, desired physical properties, and the like.

[0013] The perforated cylinder constituting the cylindrical filter of the present invention,
Conventionally known materials, for example, those made of metal or plastic can be used. Further, the cylindrical filter of the present invention has the above-described basic configuration, but in order to prevent the treatment fluid from dissipating, both ends of the cylindrical filter can be closed with caps or the shape of the cylindrical filter can be maintained. As described above, a conventionally used configuration such as a perforated net made of metal or plastic may be provided on the outermost surface of the cylindrical filter.

[0014] The cylindrical filter of the present invention is, for example, food / beverage, electronics, pharmaceutical, chemical, water treatment, photography, paint, plating,
It can be suitably used for dyeing, filtration of fluids such as liquids used in various production processes such as machinery and steel, or used liquids.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0016]

(Example 1) A nozzle piece having orifices arranged at an orifice diameter of 0.3 mm and a pitch of 0.8 mm was heated to a temperature of 330 ° C., and 0.3 orifice per orifice was used.
The polypropylene resin was discharged at a rate of 3 g / min.
Melt blown fibers formed by the action of air at a temperature of 240 ° C. and a mass ratio of 240 times the resin discharge amount were accumulated on a conveyor (distance between nozzle piece and conveyor: 49 cm) to produce a melt blown fiber web. Next, this melt blown fiber web was passed through a calender roll (linear pressure: 0.5 kN / cm) consisting of a metal roll and a resin roll and set at a temperature of 80 ° C. to have an area density of 80 g / cm 2.
m ² , thickness 0.15 mm, apparent density 0.53 g / cm ³ ,
A melt-blown nonwoven fabric (main filtered nonwoven fabric) having an average fiber diameter of 1.7 µm and an average flow pore size of 1.9 µm was produced. On the other hand, a nozzle piece having orifices arranged at an orifice diameter of 0.2 mm and a pitch of 0.8 mm is heated to a temperature of 320 ° C., and a polypropylene resin is discharged at a rate of 0.06 g / min per orifice. Air is applied to the resin at a temperature of 330 ° C. and a mass ratio of 70 times the amount of the resin discharged, and melt blown fibers 2 made of polypropylene having an average fiber diameter of 1.8 μm (melting point: 160 ° C.). Two opening cylinders 3 as shown in FIG. 2 are arranged in a direction perpendicular to the flow of the polypropylene melt blown fibers 2.
1 is housed in the housing 32 and the air nozzle 33
The fiber diameter is 21.6 μm from a fiber opening machine 3 provided with a core component made of polypropylene resin (melting point: 160 ° C.) and a sheath component made of polyethylene resin (melting point: 135 ° C.).
A core-sheath type thermoplastic stretched short fiber 4 having a fiber length of 38 mm was supplied and mixed with the polypropylene meltblown fiber 2. The mixing mass ratio of the polypropylene melt-blown fiber 2 and the core-sheath type thermoplastic stretched short fiber 4 was (polypropylene melt-blown fiber 2) :( core-sheath type thermoplastic stretched short fiber 4) = 65: 35. . The polypropylene melt-blown fiber 2 and the core-sheath type thermoplastic stretched short fiber 4
The mixed fiber web was collected by a conveyor belt to form a mixed fiber web. The conveyor belt was made of a mesh body, and air was sucked from a side opposite to the collecting surface of the belt by a gas suction device to prevent disturbance of the fibers constituting the mixed fiber web. Next, the mixed fiber web is subjected to a heat treatment for 3 minutes by a dryer at a temperature of 145 ° C. to bond only the sheath component of the core-sheath type thermoplastic stretched short fiber 4 to have a surface density of 50 g / m ² and a thickness of 50 g / m ² . 0.33m
m, a mixed nonwoven fabric (first auxiliary filtered nonwoven fabric) having an average flow pore diameter of 13.7 μm. Next, in a state where the main filtration nonwoven fabric was sandwiched between the two first auxiliary filtration nonwoven fabrics, a fold folding process was performed with a fold width of 14 mm by a fold folding machine to produce a laminated filter material. Next, the laminated filter material was arranged around the perforated polypropylene cylinder so that the number of peaks was 100, and then both ends of the laminated filter material were fused by an ultrasonic welding machine. Then, gaskets are adhered to both end surfaces in the length direction of the perforated cylinder, and the inner diameter is 30 m.
m, a pleated cylindrical filter having an outer diameter of 69 mm and a length of 250 mm was produced.

(Example 2) As sea-island fibers, there are 25 island components made of polypropylene in a sea component made of poly-L-lactic acid (hereinafter, referred to as "PLLA").
Fibers produced by the composite spinning method (fineness: 1.65 dte
x, fiber length: 3 mm). Next, this sea-island type fiber is immersed in a sodium hydroxide aqueous solution at a temperature of 80 ° C. and 10 mass% for 30 minutes to extract and remove PLLA, which is a sea component of the sea-island type fiber, to obtain a polypropylene ultrafine fiber (average fiber diameter: 1). 0.8 μm, standard deviation of fiber diameter distribution:
0.15, melting point: 172 ° C., cut to a fiber length of 3 mm, unfibrillated, stretched, having substantially the same diameter in the fiber axis direction). On the other hand, as the adhesive fiber, a core-sheath composite adhesive fiber (fiber diameter: 11) in which the core component is made of polypropylene (melting point: 158 ° C) and the sheath component (adhesive component) is made of high-density polyethylene (melting point: 131 ° C). 0.8 μm, fiber length of 10 mm, non-fibrillated, stretched). Then, the polypropylene ultrafine fiber and the core-sheath type composite adhesive fiber are dispersed in a dispersing bath composed of water at a mass ratio of 50:50, and are formed by a paper machine. Only the adhesive component of the type composite adhesive fiber is adhered, and the surface density is 38 g /
m ² , thickness 0.34 mm, apparent density 0.11 g / cm ³ ,
A wet nonwoven fabric (second auxiliary filtered nonwoven fabric) having an average flow pore size of 12.1 μm was produced. The fibers constituting this wet nonwoven fabric (second auxiliary filtered nonwoven fabric) were two-dimensionally arranged, and the maximum pore diameter was 1.7 times the average flow pore diameter. On the other hand, a main filtration nonwoven fabric manufactured in exactly the same manner as in Example 1 was prepared. Next, in a state where the main filtration nonwoven fabric is sandwiched between the two second auxiliary filtration nonwoven fabrics, a folding width 1
Folding was performed at 4 mm to produce a laminated filter material.
Next, the number of peaks is 10 around the perforated polypropylene cylinder.
The laminated filter medium was arranged so that there were no peaks, and then both ends of the laminated filter medium were fused by an ultrasonic welding machine. Then, gaskets were adhered to both end surfaces in the length direction of the perforated cylinder to produce a pleated cylindrical filter having an inner diameter of 30 mm, an outer diameter of 69 mm, and a length of 250 mm.

(Comparative Example 1) The same main filtration nonwoven fabric as in Example 1 was prepared. On the other hand, areal density 34 g / m ² , thickness 0.25 m
m, apparent density 0.14 g / cm ³ , mesh size 1 mm x 2 mm
Was prepared. Next, in a state where the main filter nonwoven fabric was sandwiched between the two polypropylene nets, a fold folding process was performed with a fold width of 14 mm using a fold folding machine to produce a laminated filter material. Next, the laminated filter material was arranged around the perforated polypropylene cylinder so that the number of peaks was 100, and then both ends of the laminated filter material were fused by an ultrasonic welding machine. Then, gaskets are adhered to both end surfaces in the length direction of the perforated cylinder to have an inner diameter of 30 mm, an outer diameter of 69 mm, and a length of 250 mm.
Was manufactured.

(Example 3) Main filtered nonwoven fabric (60 cm length) manufactured in the same manner as in Example 1, and mixed nonwoven fabric (first auxiliary filtered nonwoven fabric, 320 cm in length) manufactured in the same manner as in Example 1
Head) was prepared. A melt-blown nonwoven fabric A (40 cm long) having an area density of 80 g / m ² and an average flow pore size of 3 μm;
Melt blown nonwoven fabric B (40 cm long) having an areal density of 80 g / m ² and an average flow pore size of 5 μm, and an areal density of 80 g / m 2
² , the melt-blown nonwoven fabric C (4
(0 cm length). Next, the main filtered nonwoven fabric is laminated on the mixed nonwoven fabric such that a position 120 cm from the left end of the mixed nonwoven fabric (first auxiliary filtered nonwoven fabric) coincides with the left end of the main filtered nonwoven fabric. The meltblown nonwoven fabric A is laminated on the mixed nonwoven fabric so that the right end of the filtered nonwoven fabric and the left end of the meltblown nonwoven fabric A coincide with each other, and then the right end of the meltblown nonwoven fabric A and the left end of the meltblown nonwoven fabric B match. The melt-blown non-woven fabric B is placed on the mixed non-woven fabric.
Then, the melt-blown nonwoven fabric C was laminated on the mixed nonwoven fabric so that the right end of the melt-blown nonwoven fabric B and the left end of the melt-blown nonwoven fabric C coincided with each other to produce a filter material laminate. Next, the filter material laminate is wound in a flat wound shape from the left end so that the surface of the filter material laminate on which the main filtration nonwoven fabric and the like are laminated is on the inner side, and the inner diameter is 3 cm. 6.5c diameter
m, a depth-type cylindrical filter having a length of 25 cm was manufactured.

(Comparative Example 2) The same procedure as in Example 3 was repeated, except that the same polypropylene net as in Comparative Example 1 was used instead of the first auxiliary filtration nonwoven fabric used in Example 3, and the inner diameter was 3 cm. A depth type cylindrical filter having an outer diameter of 6.5 cm and a length of 25 cm was manufactured.

The performances of the cylindrical filters of Examples 1 to 3 and Comparative Examples 1 and 2 were examined as follows. 1. Water flow resistance The pressure loss when water was passed through each of the cylindrical filters at a flow rate of 25 L / min was measured and defined as the water flow resistance. The results were as shown in Table 1. 2. Filtration Efficiency While uniformly stirring a test solution having a concentration of 10 ppm in which JIS type 11 dust is dispersed in water, water is passed through each cylindrical filter at a predetermined flow rate (25 L / min for a pleated type, and for a depth type). 10 L / min), and the filtrate 1 minute after passing the water was collected. The number of particles for each particle size contained in the filtrate and the test solution before filtration was measured by a particle size distribution analyzer (COULTER (COUL)
TER) Coulter Multisizer Two (COU)
LTER Multisizer II)).
Next, the filtration efficiency at each particle size was calculated from the following equation, and the particle size at which a filtration efficiency of 100% was obtained was defined as the filtration accuracy of the cylindrical filter. The results were as shown in Table 1. 2. Filtration efficiency [%] = {(AB) / A} × 100 A: number of particles before filtration, B: number of particles after filtration Filtration life A JIS 11 type dust dispersed in water at a specified concentration (20 ppm for a pleated type, 10 ppm for a depth type) is dispersed at a predetermined flow rate into each cylindrical filter while uniformly stirring. Water flow (25 L /
Min, 10 L / min in the case of the depth type). The pressure loss is sequentially measured for each flow rate, and the total flow rate processed until the differential pressure from the initial pressure reaches a predetermined value (200 kPa for the pleated type, 100 kPa for the depth type) The filtration life was determined. The results were as shown in Table 1.

[0022]

【table 1】 From Table 1, it was found that the pleated cylindrical filter and the depth cylindrical filter of the present invention both have low water flow resistance and excellent filtration accuracy and filtration life. In addition, the laminated filter medium comprising the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric used in the tubular filter of the present invention can be processed (folded and wound) without damaging the main filtration nonwoven fabric. Was. This shows that the main filtration non-woven fabric was not damaged during processing from the results of long filtration life and excellent filtration performance without impairing the filtration accuracy in Table 1. Moreover, the laminated filter medium of the present invention was excellent in handling workability at the time of folding and winding.

[0023]

EFFECTS OF THE INVENTION The cylindrical filters of the present invention have a long filtration life and are easy to process (for example, foldability, winding).
What is excellent.

[Brief description of the drawings]

FIG. 1 is a process diagram illustrating an example of a manufacturing process of a first auxiliary filtered nonwoven fabric.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melt blow apparatus 2 Melt blow fiber 3 Spreader 31 Spreading cylinder 32 Housing 33 Air nozzle 4 Thermoplastic drawn fiber 5 Collector 6 First auxiliary filtered nonwoven fabric

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) D21H 27/08 D21H 27/08 27/30 27/30 A F term (reference) 4D019 AA03 BA13 BB05 BB10 CA03 DA03 4L047 AA14 AA21 AA27 AA28 AB04 AB08 BA09 BA21 BB09 CA05 CA16 CB10 CC12 EA05 4L055 AF16 AF17 AF33 AF44 AF46 AF47 AJ01 BE14 FA11 GA31 GA39

Claims (7)

[Claims] Claims: 1. A main filtration non-woven fabric comprising a melt-blown non-woven fabric, and an average flow pore size larger than the main filtration non-woven fabric;
An auxiliary filtration nonwoven fabric in which melt blown fibers and thermoplastic drawn fibers are mixed, and the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are arranged adjacent to each other in a state of being laminated adjacent to each other, and are arranged around a perforated cylinder. A cylindrical filter characterized by the above-mentioned. 2. The non-woven fabric for auxiliary filtration, wherein the non-woven fabric has an average fiber diameter of 0.
1 to 20 μm melt blown fiber 5 to 95 mass%
And a thermoplastic stretched fiber 9 having an average fiber diameter of 10 to 100 μm.
The cylindrical filter according to claim 1, comprising a nonwoven fabric containing 5 to 5 mass%. 3. A main filtration nonwoven fabric made of a melt-blown nonwoven fabric, and an average flow pore size larger than the main filtration nonwoven fabric,
It is a wet nonwoven fabric produced from fibers that are not substantially fibrillated and have a fiber diameter of less than 20 μm, wherein the fibers are ultrafine fibers having a fiber diameter of 4 μm or less, and a fiber diameter of 8 μm.
As described above, an auxiliary filtration nonwoven fabric comprising a wet nonwoven fabric having a bonded pore size of less than 20 μm and having a maximum pore size of not more than twice the average flow pore size, wherein the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are adjacent to each other. A cylindrical filter characterized by being disposed around a perforated cylinder in a state of being stacked. 4. In the auxiliary filtered nonwoven fabric, a value obtained by dividing a standard deviation value of a fiber diameter distribution of the ultrafine fibers by an average value of fiber diameters of the ultrafine fibers is 0.2 or less, The cylindrical filter according to claim 3. 5. The air filter according to claim 1, further comprising a region around the perforated cylinder, in which the main filtration nonwoven fabric and the auxiliary filtration nonwoven fabric are arranged in a wound state. The cylindrical filter according to any one of the above. 6. The perforated cylinder has an area in which the main filtering nonwoven fabric and the auxiliary filtering nonwoven fabric are arranged in a folded state in a folded state. 6. The cylindrical filter according to any one of 5. The cylinder according to any one of claims 1 to 6, further comprising a region in which a coarse filtration fiber sheet having a larger average flow pore size than the auxiliary filtration nonwoven fabric is arranged. Filter.