JP2013034919A - Cartridge filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cartridge filter achieving high filtration accuracy and a long filtration life.SOLUTION: The cartridge filter configured by winding a nonwoven fabric filter around a tubular core material 14 having a hole through which a liquid passes is composed by winding at the upstream side of filtration, 7 turns or more of a rough nonwoven fabric filter 10 having 90% filtering accuracy of ≥4 μm to <10 μm and air permeability of 2-30 cc/cm/sec and by winding at the downstream side of filtration, one or more turns of a laminated nonwoven fabric filter which includes a microfiltration nonwoven fabric filter 12 having 90% filtering accuracy of ≥0.5 μm to <4 μm and air permeability of 2-30 cc/cm/sec and the above rough nonwoven fabric filter 10.

Description

  The present invention relates to a cartridge filter capable of filtering solid matter in a fluid, and more particularly to a cartridge filter capable of filtering fine particles in a liquid.

  As one of the filter media, a cartridge filter (also referred to as a depth filter) in which a filter material such as a nonwoven fabric is wound around a tubular core material having holes through which liquid can pass is used, for example, in food production and semiconductor production. ing. In developing a cartridge filter, there is always a problem that it is difficult to achieve both high filtration accuracy and a long filtration life. Specifically, in order to increase the filtration accuracy, for example, if the filter medium is configured so that the fiber diameter is small and the gap formed between the fibers is small, the pressure loss due to clogging increases. The filtration life tends to be shortened. On the other hand, if the filter medium is configured to have a long filtration life, the filtration accuracy is lowered.

In order to solve this problem, various configurations have been proposed in advance.
In Patent Document 1, a fiber assembly layer containing a heat-fusible conjugate fiber is wound around a winding core to form a support layer, and a sheet having a desired hole diameter is wound together with the fiber assembly layer on the outside of the microfiltration layer. And a cartridge filter in which only a fiber assembly layer is wound to form a prefiltration layer is disclosed. This cartridge filter has an excellent filtration life, and is fixed and stabilized by heat fusion capable of reliably capturing particles of, for example, 1 μm or less.

  Patent Document 2 includes a liquid-permeable cylindrical molded body positioned in the core, a prefiltration layer positioned outside, and a microfiltration layer positioned between the cylindrical molded body and the prefiltration layer. A cylindrical cartridge filter is disclosed. In this cartridge filter, a deep layer filtering action is achieved in which solids with relatively large particles in the liquid to be filtered are collected by the pre-filtration layer, and solids with small particles are collected by the microfiltration layer. .

Patent Document 3 discloses a depth type filter in which the filtration life is improved while increasing the fiber diameter from the inner circumference toward the outer circumference, thereby maintaining the filtration accuracy.
Furthermore, in Patent Document 4, in order to increase the filtration life, a net made of monofilament is inserted between the outer cylinder and the inner cylinder of cylindrical filter elements having different filtration performances, and a space layer is provided to improve pressure loss. It has been proposed to do.

Japanese Unexamined Patent Publication No. 55-024575 Utility Kaihei 04-099204 JP-A-11-156125 Japanese Utility Model Publication No. 5-37308

  In some fields, a filter medium with higher accuracy is required. For example, a filter medium capable of filtering particles having an average particle size of 0.7 μm with an accuracy of 90% or more, preferably 95% or more is required. . If such a filtration accuracy is to be realized in the cartridge filter, the filtration life cannot be sufficiently improved even if the above-mentioned means are used. In order to increase the filtration accuracy, it is necessary to use a dense nonwoven fabric having a smaller gap formed between the fibers as the filter medium. In such a nonwoven fabric, clogging is more likely to occur, and it is difficult to obtain a sufficient filtration life even if a conventional configuration is adopted. For example, even if the pre-filtration layer is formed with a fiber layer made of a heat-adhesive conjugate fiber as described in Patent Document 1, when a high-precision filter medium as described above is used, a sufficient filtration life is obtained. I can't get it. Moreover, even if it arrange | positions between the layer formed by winding the nonwoven fabric with a high filtration precision, and the layer formed by winding the nonwoven fabric with a low filtration precision, for example, the net | network as described in patent document 4 is enough. The filtration life cannot be obtained.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a cartridge filter that realizes high filtration accuracy and a long filtration life.

The present inventors examined the structure which provides a coarse filtration nonwoven fabric on the outer side of a microfiltration nonwoven fabric with reference to literature 2-3. Specifically, the cylindrical filter of the structure formed by winding the laminated body which provided the coarse filtration nonwoven fabric between the microfiltration nonwoven fabric layer and the support nonwoven fabric which consists of a heat-fusible composite fiber web was examined. as a result,
・ Simply adding a coarse filtration nonwoven fabric to the outside of the microfiltration layer may not improve the filtration life. ・ Set the relationship between the number of turns of the fine filtration nonwoven fabric and the number of turns of the coarse filtration nonwoven fabric within the specified range. As a result, it was found that a cylindrical filter having both excellent filtration accuracy and filtration life was obtained, and the present invention was achieved.

The present invention
A cartridge filter in which a filtration nonwoven fabric is wound around a tubular core material (hereinafter also referred to as a “core material”) having holes through which fluid passes,
A 90% filtration accuracy is 4 μm or more and less than 10 μm, and a coarse filtration nonwoven fabric having an air permeability of ² cc / cm ² / second to 30 cc / cm ² / second is wound 7 or more times on the upstream side of the filtration,
A laminated filtration nonwoven fabric comprising a fine filtration nonwoven fabric having a 90% filtration accuracy of 0.5 μm or more and less than 4 μm and an air permeability of ² cc / cm ² / second to 30 cc / cm ² / second and the coarse filtration nonwoven fabric is filtered. Wound more than one turn on the downstream side,
Provide a cartridge filter.

  The cartridge filter of the present invention includes a specific microfiltration nonwoven fabric and a specific coarse filtration nonwoven fabric, a laminated filtration nonwoven fabric is wound on the filtration downstream side, and the specific coarse filtration nonwoven fabric is wound on the filtration upstream side for seven or more turns. It is characterized by. With this configuration, the cartridge filter of the present invention ensures high filtration accuracy by the microfiltration nonwoven fabric and has a sufficient filtration life by the coarse filtration nonwoven fabric.

  The cartridge filter of the present invention may have a supporting nonwoven fabric having a 90% filtration accuracy of 10 μm or more. In that case, the supporting nonwoven fabric is wound together with the coarse filtration nonwoven fabric on the upstream side of the filtration and the laminated filtration nonwoven fabric on the downstream side of the filtration. The supporting nonwoven fabric supports the filtering nonwoven fabric and facilitates the winding operation.

In the cartridge filter of the present invention, the microfiltration nonwoven fabric is preferably a melt blown nonwoven fabric having a CV value of 60 to 200. The CV value is a value represented by the following equation, indicates a variation coefficient of the fiber diameter, and is a value indicating variation in the fiber diameter.
CV value = (standard deviation / average fiber diameter) × 100
A melt blown nonwoven fabric having a CV value within this range has a variation in fiber diameter, a large fiber diameter distribution, fibers having a fiber diameter larger than the average fiber diameter, and fibers having a fiber diameter smaller than the average fiber diameter. Including. Therefore, this melt blown nonwoven fabric is preferably used because it has better filtration accuracy and filtration life than a nonwoven fabric composed only of fibers having a fiber diameter near the average fiber diameter.

  In the cartridge filter of the present invention, a laminated filtration nonwoven fabric in which a specific microfiltration nonwoven fabric and a specific coarse filtration nonwoven fabric are combined is wound on the downstream side of the filtration, and the microfiltration nonwoven fabric is wound on a predetermined region on the upstream side of the filtration. It is not rotated, and has a configuration in which the coarse filtration nonwoven fabric is wound seven or more times. Thereby, high filtration accuracy and a long filtration life are achieved. Therefore, the cartridge filter of the present invention is suitable for filtering fluids such as pure water, drinking water, chemicals, various oils and fats, plating solutions, coating solutions, or cleaning water for electronics industry, particularly cleaning solutions for semiconductors.

It is a schematic diagram which shows an example of the method of manufacturing the cartridge filter of this invention. It is a schematic diagram which shows another example of the method of manufacturing the cartridge filter of this invention. It is a perspective view which shows an example of the cartridge filter of this invention, Comprising: It is a perspective view which decomposes | disassembles and shows a part.

  The cartridge filter of the present invention includes a region in which a laminated filtration nonwoven fabric including a microfiltration nonwoven fabric and a coarse filtration nonwoven fabric is wound, and a region in which the microfiltration nonwoven fabric is not wound and the coarse filtration nonwoven fabric is wound. In each region, a supporting nonwoven fabric, a net-like material, and / or an intermediate filtration nonwoven fabric are wound as necessary. Therefore, first, these nonwoven fabrics will be described.

[Microfiltration nonwoven fabric]
The microfiltration nonwoven fabric is a nonwoven fabric having a 90% filtration accuracy of 0.5 μm or more and less than 4 μm and an air permeability of ² cc / cm ² / second to 30 cc / cm ² / second. Here, the 90% filtration accuracy is a value indicating the maximum particle size that can block 90% of the particles in the microfiltration nonwoven fabric, that is, when the blocking rate for each particle size of various particles is measured. , Which is the maximum value among the particle sizes at which the blocking rate is 90% or more, and is a value measured by the following measuring method. The air permeability refers to a value measured according to the fragile method in accordance with JIS L 1096 8.27 A method.
<90% filtration accuracy>
A test suspension according to JIS Z8901 (JIS 11 species) is dispersed in water to prepare a test suspension, and the number (M) of the dust contained in the test suspension for each particle size (M) and the suspension for the test are prepared. The suspension is filtered using a target nonwoven fabric at a flow rate of 40 liters / minute, and the number (N) of each dust particle size contained in the filtrate for 5 minutes after the start of filtration is determined by a particle size distribution analyzer (trade name: Coulter Counter ZM type: manufactured by Coulter Electronics Co., Ltd.). The blocking rate was calculated from the following formula for each particle size, and the particle size at which the blocking rate was 90% was defined as 90% filtration accuracy.
Blocking rate (%) = [(MN) × 100] / M

  The microfiltration nonwoven fabric has a 90% filtration accuracy of 0.5 μm or more and less than 4 μm. When a microfiltration nonwoven fabric having a 90% filtration accuracy of 0.5 μm or more and less than 4 μm is used, a highly accurate cartridge filter can be obtained. From the viewpoint of obtaining a cartridge filter with higher accuracy, the 90% filtration accuracy of the microfiltration nonwoven fabric is preferably 0.6 μm to 3 μm, and more preferably 0.7 μm to 2 μm.

The microfiltration nonwoven fabric has an air permeability of ² cc / cm ² / second to 30 cc / cm ² / second. When a microfiltration nonwoven fabric having an air permeability of ² cc / cm ² / second or more is used, the microfiltration nonwoven fabric is hardly clogged, and the filtration life can be extended. Moreover, if the microfiltration nonwoven fabric whose air permeability is 30 cc / cm < ² > / sec or less is used, the re-release | release of the capture | acquired particle | grains can be suppressed. From this point of view, air permeability of the microfiltration nonwoven is preferably 3 cc / cm ² / sec ~15cc / cm ² / sec, more preferably 4 cc / cm ² / sec ~10cc / cm ² / sec .

  Since the microfiltration nonwoven fabric of the present invention has a specific 90% filtration accuracy and a specific air permeability, it is excellent in surface filterability. Usually, the nonwoven fabric captures particles on its surface and inside, but the microfiltration nonwoven fabric used in the present invention is particularly excellent in the ability to capture particles on the nonwoven fabric surface. In the present invention, since the fine filtration nonwoven fabric is wound together with the coarse filtration nonwoven fabric on the downstream side of the filtration, the fine filtration nonwoven fabrics do not adhere to each other in the radial direction of the cartridge filter, and a fine space is formed by the coarse filtration nonwoven fabric. It is formed. Therefore, the fluid to be treated can be subjected to surface filtration with a microfiltration nonwoven fabric by the number of windings while it passes through the radial direction of the cartridge filter.

  The type and material of the microfiltration nonwoven fabric are not particularly limited as long as it has 90% filtration accuracy and air permeability within the above ranges. For example, the microfiltration nonwoven fabric may be a spunbond nonwoven fabric composed of long fibers, or a meltblown nonwoven fabric obtained by a meltblowing method. Alternatively, the microfiltration nonwoven fabric can be obtained from short fibers (for example, fibers having a fiber length of 3 mm to 100 mm) by using a wet papermaking method or a card machine, a parallel web, a semi-random web, a random web, a cross web, or a cross web. It may be obtained by producing a web by a card method to be produced or an air array method, and further integrating the web. The web integration is performed by one or more methods selected from adhesive bonding, thermal bonding by softening or melting the fibers, needle punching, and high pressure water flow treatment. The microfiltration nonwoven fabric may be a nonwoven fabric in which two or more nonwoven fabrics are laminated.

Microfiltration nonwoven preferably has a basis weight is ^{5g / m 2 ~40g / m 2} . When the basis weight of the microfiltration nonwoven fabric is 5 g / m ² or more, it is easy to handle and, for example, when wound around the tubular core material, it is difficult to cut. In addition, when the basis weight of the microfiltration nonwoven fabric is 40 g / m ² or less, the number of winding times of the microfiltration nonwoven fabric can be increased, and as a result, the surface filtration area per mass of the microfiltration nonwoven fabric is increased, which is more excellent. Filtration accuracy can be obtained. From the viewpoint of remarkably obtaining such an effect, the basis weight of the microfiltration nonwoven fabric is more preferably 30 g / m ² or less, and the basis weight is further preferably 20 g / m ² or less.

In the present invention, precise basis weight of filtration nonwoven by a ^{5g / m 2 ~40g / m 2} , in a cartridge filter of a given outer diameter, microfiltration nonwoven and / or coarse filtration nonwoven predetermined number winding Cheap. When the outer diameter and / or inner diameter of the cartridge filter is determined, such as when the cartridge filter is used in a plastic case, etc., the basis weight of the microfiltration nonwoven fabric is reduced, and the microfiltration nonwoven fabric and / or Or more coarse filtration nonwoven fabrics can be wound.

  Since a microfiltration nonwoven fabric should capture small solids, that is, fine particles, it is generally a nonwoven fabric composed of fibers having a small fiber diameter and a small gap between fibers. Specifically, the microfiltration nonwoven fabric is composed of fibers having an average fiber diameter of 0.1 μm to 10 μm, preferably 0.5 μm to 5 μm. Here, the fiber diameter refers to the diameter when the fiber cross-sectional shape is circular, and refers to the diameter when converted into a circular cross section when the fiber cross-sectional shape is non-circular. Moreover, an average fiber diameter expands and observes the nonwoven fabric surface 100 to 1000 times using an electron microscope, measures arbitrary 100 fiber side surfaces (width | variety), and calculates the average value of the measured value. By seeking. When a plurality of fibers are fused and the boundary is unknown, measurement is performed by regarding the fused fiber group as one fiber.

  A fiber having such an average fiber diameter can be obtained, for example, by adjusting the size of a nozzle for discharging the fiber material, the fiberizing conditions, and the like when a nonwoven fabric is produced by a spunbond method or a melt blow method. Or the fiber which has such an average fiber diameter is formed by splitting of a split type composite fiber. The split-type conjugate fiber has at least one component divided into two or more components in the fiber cross section, and at least a part of the component is exposed on the fiber surface, and the exposed portion is continuous in the fiber length direction It has a fiber cross-sectional structure that is formed. The cross-sectional shape of the split-type conjugate fiber has, for example, a circular or irregular solid shape, or a hollow cross-section. Examples of the divided shape in the fiber cross section include a radial shape and a layer shape. Or the fiber which has such an average fiber diameter can be obtained by eluting the sea component of a sea-island type composite fiber.

  The microfiltration nonwoven fabric is preferably a meltblown nonwoven fabric obtained by a meltblowing method. The melt blown nonwoven fabric can also be obtained as a fiber having a large distribution of fiber diameters. In that case, since the fiber contains fibers having a fiber diameter larger than the average fiber diameter and fibers having a fiber diameter smaller than the average fiber diameter, the average fiber diameter It is superior in filtration accuracy and filtration life as compared with a non-woven fabric composed only of fibers having a nearby fiber diameter. Moreover, the nonwoven fabric which has the below-mentioned CV value can be easily obtained as a microfiltration nonwoven fabric is a melt blown nonwoven fabric.

The microfiltration nonwoven fabric preferably has a CV value of 60 to 200. Here, the CV value is a value represented by the following equation, indicates a variation coefficient of the fiber diameter, and is a value indicating variation in the fiber diameter.
CV value = (standard deviation / average fiber diameter) × 100

  When the CV value of the microfiltration nonwoven fabric is 60 or more, there is a large variation in fiber diameter, and the fiber contains a fiber having a large fiber diameter and a fiber having a small fiber diameter. Such a non-woven fabric has a relatively small fiber constituted by fibers having a small fiber diameter, in which a relatively large inter-fiber gap constituted by fibers having a large fiber diameter facilitates passage of particles and suppresses an increase in pressure loss. The interstitial space captures the fine particles. Therefore, when such a nonwoven fabric is used, it is possible to obtain a cartridge filter that is highly accurate but hardly clogged. Moreover, by including a fiber with a large fiber diameter, the tensile strength of the nonwoven fabric is increased, and it becomes difficult to be cut during winding. Furthermore, even when the compressive strength of the nonwoven fabric is increased and the winding pressure is increased, the nonwoven fabric is less likely to be crushed. From the viewpoint of remarkably obtaining such an effect, the CV value is more preferably 100 or more, and further preferably 120 or more.

  When the CV value of the microfiltration nonwoven fabric is 200 or less, the variation does not become too large, and variations in the filtration accuracy of each cartridge filter can be suppressed. From the viewpoint of remarkably obtaining such an effect, the CV value is more preferably 180 or less, and further preferably 150 or less.

  The microfiltration nonwoven fabric preferably contains 5% to 30%, more preferably 10% to 25%, of fibers having a fiber diameter of 0.5 μm or less. Moreover, it is preferable that 10%-70% of fiber with a fiber diameter of 1 micrometer or less is contained by several minutes, and it is more preferable that 30%-60% is included. The fraction is the percentage of the number of fibers having a predetermined fiber diameter in the non-woven fabric in the total number of fibers.

  The microfiltration nonwoven fabric preferably contains 1% to 30%, more preferably 5% to 20%, of fibers having a fiber diameter of 4 μm or more in several minutes. Further, it is preferable that fibers having a fiber diameter of 8 μm or more are contained in an amount of 1% to 10%, more preferably 2% to 5%.

  The material which comprises a microfiltration nonwoven fabric is not specifically limited. For example, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate; low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, Various polyethylene resins such as ultra high molecular weight polyethylene, various polypropylene resins such as isotactic, atactic and syndiotactic polymerized using ordinary Ziegler-Natta catalysts and metallocene catalysts, various polymethylpentene resins, Various polyolefin resins such as ethylene-vinyl alcohol copolymer resin and ethylene-propylene copolymer resin; polyamide resins such as nylon 6, nylon 66, nylon 11 and nylon 12 ; Polycarbonates, polyacetals, polystyrene, engineering plastics, etc., such as cyclic polyolefin, may constitute microfiltration nonwoven. The fibers constituting the microfiltration nonwoven fabric may be single fibers (including fibers formed by splitting of split-type composite fibers), or core-sheath types (concentric and eccentric), side-by-side types, split-type composites It may be a composite fiber such as a fiber in which the fibers are not completely split and a plurality of components are bonded.

  The surface of the microfiltration nonwoven fabric is preferably not formed into a film. When thermal processing such as calendering is performed on the surface of the nonwoven fabric, a part or all of the resin on the processed surface may be melted to form a film. The microfiltration nonwoven fabric of the present invention is preferably a nonwoven fabric that has not been subjected to such heat processing.

  Such a microfiltration nonwoven fabric may have an average flow pore size of 1 μm to 8 μm, preferably 1.5 μm to 6 μm, and more preferably 2 μm to 4 μm. When the average flow pore size is 1 μm to 8 μm, it is easy to obtain a nonwoven fabric having a desired 90% filtration accuracy.

  Alternatively, the microfiltration nonwoven fabric may have a maximum pore diameter of 1 μm to 15 μm, preferably 2 μm to 12 μm, and more preferably 3 μm to 8 μm. It is easy to obtain the nonwoven fabric which has desired air permeability as the largest hole diameter is 1 micrometer-15 micrometers.

In the present invention, trade names “Syntex-nano3” and “Syntex-nano6” (weight per unit area 15 g / m ² ) (manufactured by Mitsui Chemicals, Inc.) are particularly preferably used as the meltblown nonwoven fabric for the microfiltration nonwoven fabric.

[Rough filtration nonwoven fabric]
The coarse filtration nonwoven fabric is a coarser nonwoven fabric than the microfiltration nonwoven fabric. Specifically, the 90% filtration accuracy is 4 μm or more and 10 μm or less, and the air permeability is ² cc / cm ² / second to 30 cc / cm ² / second. It is the nonwoven fabric which is. Here, 90% filtration accuracy and air permeability are values measured in the same manner as that of the microfiltration nonwoven fabric.

  The coarsely filtered nonwoven fabric has a 90% filtration accuracy of 4 μm or more and less than 10 μm. When the 90% filtration accuracy is 4 μm or more, the coarse filter nonwoven fabric wound on the upstream side of the filtration is hardly clogged, and a cartridge filter having an excellent filtration life can be obtained. Also, when using a coarse filtration nonwoven fabric having a 90% filtration accuracy of 10 μm or less, the coarse filtration nonwoven fabric captures relatively large particles on the upstream side of the filtration, so that the laminated filtration nonwoven fabric on the downstream side of the filtration is less likely to be clogged. A cartridge filter having an excellent filtration life can be obtained. From the viewpoint of remarkably obtaining such an effect, the 90% filtration accuracy of the coarsely filtered nonwoven fabric is preferably 5 μm to 9 μm.

The coarsely filtered nonwoven fabric has an air permeability of ² cc / cm ² / second to 30 cc / cm ² / second. When a coarse filtration nonwoven fabric having an air permeability of ² cc / cm ² / second or more is used, the coarse filtration nonwoven fabric is hardly clogged and the filtration life can be extended. Moreover, if the coarse filtration nonwoven fabric is used when the air permeability is 30 cc / cm ² / second or less, the re-release of the captured particles can be suppressed. From this point of view, air permeability of the coarse filtration nonwoven fabric is preferably 5 cc / cm ² / sec ~27cc / cm ² / sec, more preferably 10 cc / cm ² / sec ~25cc / cm ² / sec .

  The air permeability of the coarsely filtered nonwoven fabric is preferably larger than that of the finely filtered nonwoven fabric. When the air permeability of the two nonwoven fabrics satisfies this relationship, the laminated filtration nonwoven fabric wound on the downstream side of the filtration has a configuration in which the air permeability is alternately formed. Surface filtration is performed efficiently. Specifically, a value obtained by dividing the air permeability of the coarse filter nonwoven fabric by the air permeability of the fine filter nonwoven fabric is preferably 1.5 to 7, and more preferably 2 to 5.

  Since the coarse filtration nonwoven fabric of the present invention has a specific 90% filtration accuracy and a specific air permeability, it acts as a prefilter for the laminated filtration nonwoven fabric on the upstream side of the filtration. Moreover, a coarse filtration nonwoven fabric forms the space where a fluid to be filtered easily passes between the microfiltration nonwoven fabrics on the downstream side of the filtration, and acts so that the microfiltration nonwoven fabric can exhibit surface filtration performance for each turn.

Coarse filtration nonwoven is preferably basis weight is ^{5g / m 2 ~200g / m 2} . When the basis weight of the coarse filtration nonwoven fabric is 5 g / m ² or more, in the laminated filtration nonwoven fabric on the downstream side of filtration, a space through which the fluid to be filtered can easily pass can be formed between the fine filtration nonwoven fabrics. Further, when the basis weight of the coarsely filtered nonwoven fabric is 200 g / m ² or less, the number of turns of the roughly filtered nonwoven fabric per mass can be increased. From the viewpoint of obtaining such an effect significantly, the basis weight of the coarse filtration nonwoven more preferably from ^{15g / m 2 ~100g / m 2} , further preferably ^{30g / m 2 ~80g / m 2} .

The coarsely filtered nonwoven fabric preferably has a thickness measured by the following measurement method of 0.05 mm to 1 mm.
<Thickness>
Using a micrometer (trade name: Coolant Proof Micrometer 293-230 MDC-25MJ: manufactured by Mitutoyo Corporation), the dimensions of any 10 points in the thickness direction of the nonwoven fabric were measured, and the average value was calculated. It was.

  When the thickness of the coarse filtration nonwoven fabric is 0.05 mm or more, in the laminated filtration nonwoven fabric, a space through which fluid easily passes can be formed between the fine filtration nonwoven fabrics, and the filtration life is improved. Moreover, when the thickness of the coarsely filtered nonwoven fabric is 1 mm or less, it is possible to suppress re-release of the captured particles. From the viewpoint of obtaining the effect more remarkably, the thickness of the coarsely filtered nonwoven fabric is more preferably 0.1 mm to 0.5 mm, and further preferably 0.2 mm to 0.4 mm.

  The coarsely filtered nonwoven fabric is preferably a meltblown nonwoven fabric obtained by a meltblowing method. The meltblown nonwoven fabric can also be obtained as a nonwoven fabric having a large fiber diameter distribution. In meltblown nonwoven fabrics, particles can easily pass through interfiber gaps composed of fibers with a large fiber diameter, and fine particles are captured in interfiber gaps composed of fibers with small fiber diameters, so a coarsely filtered nonwoven fabric made of meltblown nonwoven fabrics It is difficult to clog even if it is wound multiple times. Moreover, according to the melt blow method, it is easy to obtain a nonwoven fabric with a small thickness.

  The coarsely filtered nonwoven fabric is preferably composed of fibers having an average fiber diameter of 0.1 μm to 10 μm, and more preferably composed of fibers having an average fiber diameter of 0.5 μm to 5 μm. When the average fiber diameter is 0.1 μm to 10 μm, it is easy to obtain a nonwoven fabric having a desired 90% filtration accuracy and air permeability.

  The fibers constituting the coarse filtration nonwoven fabric and the fibers constituting the fine filtration nonwoven fabric preferably have the same average fiber diameter. When the average fiber diameter of the fibers constituting each of the coarse filtration nonwoven fabric and the microfiltration nonwoven fabric is approximately the same, it is possible to prevent particles from being clogged by a part of the cartridge filter during liquid passage and difficult to pass. . Specifically, the value obtained by dividing the average fiber diameter of the fibers constituting the coarse filtration nonwoven fabric by the average fiber diameter of the fibers constituting the fine filtration nonwoven fabric is preferably 0.5 to 2.

  The coarsely filtered nonwoven fabric preferably has a CV value of 30 to 150, and more preferably 50 to 100. When the CV value is within such a range, the effect as a prefilter on the upstream side of the filtration and the effect of forming a space on the downstream side of the filtration can be obtained more remarkably due to variations in the fiber diameter distribution.

  The coarse filter nonwoven fabric preferably has an average flow pore size of 8 μm to 20 μm, and more preferably 9 μm to 15 μm. When the average flow pore size is 8 μm to 20 μm, it is easy to obtain a nonwoven fabric having a desired 90% filtration accuracy.

  The coarse filter nonwoven fabric preferably has a maximum pore size of 10 μm to 30 μm, and more preferably 15 μm to 25 μm. It is easy to obtain the nonwoven fabric which has desired air permeability as the largest hole diameter is 10 micrometers-30 micrometers.

  The type and material of the coarsely filtered nonwoven fabric are not particularly limited as long as they have 90% filtration accuracy and air permeability within the above ranges. The coarse filtration nonwoven may be a nonwoven of the type described with respect to the microfiltration nonwoven and may be formed using the fibers and materials described with respect to the microfiltration nonwoven. The coarsely filtered nonwoven fabric may be formed by laminating two or more nonwoven fabrics as long as it has 90% filtration accuracy and air permeability within the above ranges. In addition, unless otherwise indicated, the physical property of a coarse filtration nonwoven fabric means the value measured by the method similar to a microfiltration nonwoven fabric.

In the present invention, as the melt-blown nonwoven fabric for the coarse filtration nonwoven fabric, the trade name “PO50FW” (weight per unit area: 50 g / m ² ) (manufactured by Tapirs Co., Ltd.) is particularly preferably used.

[Intermediate filtration nonwoven fabric]
The cartridge filter of the present invention may further include a filtration nonwoven fabric that is coarser than the fine filtration nonwoven fabric and finer than the coarse filtration nonwoven fabric. Such a filtration nonwoven fabric is called an intermediate filtration nonwoven fabric for convenience. The intermediate filtration nonwoven fabric is a nonwoven fabric whose 90% filtration accuracy is larger than those of the microfiltration nonwoven fabric and whose 90% filtration accuracy is smaller than those of the coarse filtration nonwoven fabric. The intermediate filtration nonwoven fabric is disposed so as to be positioned between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric, thereby further increasing the filtration accuracy of the cartridge filter.

  In the laminated filtration nonwoven fabric, the filtration filtration nonwoven fabric and the filtration filtration nonwoven fabric other than the coarse filtration nonwoven fabric (excluding the support nonwoven fabric) are laminated, and the laminate of the precision filtration nonwoven fabric and the other filtration nonwoven fabric as a whole is within the above range. In the case of having% filtration accuracy and air permeability, it is considered that the other filtration nonwoven fabric constitutes a microfiltration nonwoven fabric. Or, when the laminate of the microfiltration nonwoven fabric and the other filtration nonwoven fabric has 90% filtration accuracy and air permeability within the above range as a whole, the other filtration nonwoven fabric constitutes a coarse filtration nonwoven fabric. I reckon. The other nonwoven fabric cannot be regarded as constituting a microfiltration nonwoven fabric or a coarse filtration nonwoven fabric, and has an eye roughness between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric (that is, 90% filtration accuracy). If so, the other nonwoven fabric is an intermediate filtration nonwoven fabric.

  The intermediate filtration nonwoven may be a nonwoven of the type described with respect to the microfiltration nonwoven and may be formed using the fibers and materials described with respect to the microfiltration nonwoven. The intermediate filtration nonwoven fabric may be formed by laminating two or more nonwoven fabrics as long as the overall roughness of the intermediate filtration nonwoven fabric is between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric.

[Supported non-woven fabric]
The support nonwoven fabric is preferably used to prevent the nonwoven fabric from being wrinkled or damaged and to facilitate the winding operation when the coarse filtration nonwoven fabric and the microfiltration nonwoven fabric are wound around the core material. . The supporting nonwoven fabric is a nonwoven fabric that is sufficiently coarser than the coarse filtration nonwoven fabric, and is not particularly limited as long as it can withstand the force applied during winding. The support nonwoven may be a nonwoven of the type described for the microfiltration nonwoven and may be formed using the fibers and materials described for the microfiltration nonwoven.

Specifically, the supporting nonwoven fabric is produced using a core-sheath composite fiber having an average fiber diameter of 5 μm to 50 μm and a sheath / core made of a combination of polyethylene / polypropylene, and the fibers are thermally bonded to each other by polyethylene. It has a basis weight may be a thermal bonding nonwoven ^{5g / m 2 ~100g / m 2} . Such a heat-bonding nonwoven fabric is a nonwoven fabric having a 90% filtration accuracy of 10 μm or more and sufficiently coarser than the coarse filtration nonwoven fabric. Preferably, the supporting nonwoven fabric has an air permeability of 50 cc / cm ² / second or more.

[Net-like]
The laminated filtration nonwoven fabric including the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric may include a net-like material between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric. In the cartridge filter, the opening portion of the net-like material forms a thin space between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric. The space contributes to the improvement of the filtration life. It is considered that this is because close contact between the fine filtration nonwoven fabric and the coarse filtration nonwoven fabric is prevented by the space, and as a result, an increase in pressure loss in the microfiltration nonwoven fabric is alleviated.

Net-like material, for example, diameter 100 m to 1000 m, preferably formed of a filament having a diameter of 200Myuemu～800myuemu, area per opening section one eye is a net-like material is ^{1 mm} 2 100 mm ^2. The filaments are, for example, monofilaments and spun yarns. The diameter of the striatum is measured by observing with an electron microscope or the like. When the linear body does not have a circular cross section like a tape, the thickness of the net is preferably in the range of 100 μm to 2000 μm. The diameter of the filament is a dimension measured at a location other than the intersection of the net-like object, and the thickness is a dimension measured at the intersection of the net-like object. In a net-like object obtained by extending an extruded net, the thickness of the striatum may not be constant between the intersection points. In that case, it is preferable that the diameter of the thickest part etc. exist in the said range.

  The shape of the opening portion may be any of a square, a rectangle, a rhombus, a triangle, and other polygons, a circle, and an ellipse, or an irregular shape. The net-like object may be a woven net, an extruded net, or an expanded metal net.

The material of the net-like material is not particularly limited, and may be formed of, for example, one or a plurality of resins exemplified above for the microfiltration nonwoven fabric. The net-like material is preferably formed of a polypropylene resin.
In the present invention, as the net-like material, in particular, the trade name “Conwed Net R07107” (manufactured by JX Nippon Mining & Metals Anci Corporation) is preferably used.

[Laminated filtration nonwoven fabric]
In the cartridge filter of the present invention, the laminated filtration nonwoven fabric located on the downstream side of filtration includes at least a coarse filtration nonwoven fabric and a microfiltration nonwoven fabric. The laminated filtration nonwoven fabric may further include one or more layers selected from a support nonwoven fabric, an intermediate filtration nonwoven fabric, and a net-like material. In that case, when the laminated nonwoven fabric is wound around the core material, the support nonwoven fabric may be disposed at any position, and may be disposed, for example, on the filtration upstream side or the filtration downstream side. The net-like material is disposed between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric. The intermediate filtration nonwoven fabric is disposed between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric.

  In the laminated filtration nonwoven fabric, the microfiltration nonwoven fabric is preferably located on the downstream side of the filtration relative to the coarse filtration nonwoven fabric. With such a configuration, the coarse filtration nonwoven fabric acts as a prefilter for the microfiltration nonwoven fabric, so that the filtration accuracy and filtration life of the cartridge filter are improved.

  The layer and the layer constituting the laminated filtration nonwoven fabric may or may not be joined. Bonding may be performed using a suitable adhesive, or may be performed by thermal bonding in which fibers constituting any one or more nonwoven fabrics are melted or softened by heat. In the laminated filtration nonwoven fabric, it is preferable that the nonwoven fabrics are not joined to each other unless wrinkles and damage occur in the nonwoven fabric or net of each layer. Filtration is not performed at the joined locations, and the filtration area is reduced.

[Cartridge filter]
Next, the structure and manufacturing method of the cartridge filter will be described.
In general, the cartridge filter has a configuration in which a filtration nonwoven fabric is wound around a tubular core material having holes through which a fluid passes. The core material may be a perforated cylindrical body made of plastic, or by winding a fiber web containing heat-adhesive fibers around a core rod while heating, or filling the fiber web into a cylindrical container. Or a fiber molded body obtained by heating. Any of the cores does not substantially impede the passage of fluid flowing from the outer peripheral side to the inner peripheral side, or from the outer peripheral side to the inner peripheral side, for example, 50 cc / cm ² / second or more, preferably It has an air permeability of 80 cc / cm ² / sec or more.

  The cartridge filter of the present invention is configured by winding a predetermined number of turns of a laminated filtration nonwoven fabric and a coarse filtration nonwoven fabric around a core material. When the filtration is performed by passing the fluid from the outer peripheral side of the cartridge filter toward the inner peripheral side, the outer peripheral side of the cartridge filter is the upstream filtration side, and the inner peripheral side is the downstream filtration side. Therefore, the laminated filtration nonwoven fabric including the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric is wound on the inner peripheral side of the cartridge filter, the coarse filtration nonwoven fabric is wound on the outer peripheral side, and the microfiltration nonwoven fabric is not wound. When the filtration is performed by passing the fluid from the inner peripheral side of the cartridge filter toward the outer peripheral side, the inner peripheral side of the cartridge filter is the upstream filtration side, and the outer peripheral side is the downstream filtration side. Therefore, the laminated filtration nonwoven fabric including the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric is wound on the outer peripheral side of the cartridge filter, the coarse filtration nonwoven fabric is wound on the inner peripheral side, and the microfiltration nonwoven fabric is not wound.

  The cartridge filter of the present invention is characterized in that a laminated filtration nonwoven fabric including a microfiltration nonwoven fabric and a coarse filtration nonwoven fabric is wound on the downstream side of filtration. With this configuration, the present invention is superior in filtration accuracy and filtration life to a cartridge filter in which only a microfiltration nonwoven fabric is wound on the downstream side of filtration. Cartridge filters in which only the microfiltration nonwoven fabric is wound on the downstream side of filtration are in close contact with each other, so that it is as if a microfiltration nonwoven fabric with a large basis weight was wound only once. This is performed in the first round when the target fluid first comes into contact. On the other hand, in the cartridge filter of the present invention, while the coarse filtration nonwoven fabric in the laminated filtration nonwoven fabric prevents adhesion between the fine filtration nonwoven fabrics and forms a minute space, the fluid passes through in the radial direction. In addition, surface filtration is performed with a microfiltration nonwoven fabric by the number of windings.

  In the cartridge filter of the present invention, when the laminated filtration nonwoven fabric includes a support nonwoven fabric, it is preferably wound so that the support nonwoven fabric and the microfiltration nonwoven fabric are adjacent to each other and the support nonwoven fabric is on the filtration downstream side. With such a configuration, since the fluid that has passed through the microfiltration nonwoven fabric is directed to the support nonwoven fabric having a low resistance to liquid passage, the microfiltration nonwoven fabric is not easily clogged.

  On the upstream side of the filtration, the coarse filtration nonwoven fabric is wound 7 or more times, preferably 10 or more times, more preferably 20 or more times. If the number of turns of the coarsely filtered nonwoven fabric is less than 7 turns, the effect of the coarsely filtered nonwoven fabric cannot be obtained, and the filtration life cannot be extended. The upper limit of the number of turns of the coarsely filtered nonwoven fabric is not particularly limited, and is determined by the dimensions of the cartridge filter to be finally obtained, the dimensions of the core material, the thickness of the filtered nonwoven fabric, and the like. For example, when obtaining a cartridge filter having an outer diameter of 50 mm to 100 mm, the upper limit is about 80 turns.

  On the downstream side of the filtration, the laminated filtration nonwoven fabric is wound one or more times so that fine particles are removed by the microfiltration nonwoven fabric. The laminated filtration nonwoven fabric is preferably wound three or more times, more preferably 5 to 12 turns.

  A cartridge filter in which a laminated filtration nonwoven fabric is wound three or more times, preferably five or more times on the downstream side of the filtration, is particularly excellent in capturing of fine particles. Particles having a small particle size (for example, a particle size of 1 μm or less) dispersed in a fluid are aggregated with two or more particles to form an aggregated particle having a large apparent particle size. In the cartridge filter of the present invention, it is considered that fine particles smaller than the pore diameter of the microfiltration nonwoven fabric can be captured by capturing the aggregated particles. Specifically, in the laminated filtration nonwoven fabric in the cartridge filter, the coarse filtration nonwoven fabric forms a minute space in which minute particles easily flow, increases the collision frequency between the particles, and forms a state in which aggregated particles are easily generated. Then, the aggregated particles are captured by a microfiltration nonwoven fabric. Next, the fine particles that have passed through the microfiltration nonwoven fabric are similarly agglomerated while passing through the next coarse filtration nonwoven fabric, and are captured by the next microfiltration nonwoven fabric. Similarly, this filtering action is repeated by the number of turns of the laminated nonwoven fabric. By capturing the aggregated particles on each circumference in this way, the cartridge filter in which the laminated filtration nonwoven fabric is wound three or more times can disperse the clogging caused by the particle capture on each circumference, so that the filtration life is long. It becomes a cartridge filter.

  When the intermediate filtration nonwoven fabric is arranged, it is preferable that the intermediate filtration nonwoven fabric is wound with the coarse filtration nonwoven fabric at least after the microfiltration nonwoven fabric is wound to form a multistage filtration layer on the upstream side of the filtration. . The intermediate filtration nonwoven fabric is wound together with the microfiltration nonwoven fabric so that the winding start side end of the intermediate filtration nonwoven fabric and the winding start side end of the microfiltration nonwoven fabric coincide with each other. A nonwoven fabric may be formed. The intermediate filtration nonwoven fabric has the same length as the coarse filtration nonwoven fabric, and may be wound the same number of turns as the coarse filtration nonwoven fabric on the upstream side of the filtration. Alternatively, the intermediate filtration nonwoven fabric may be shorter than the coarse filtration nonwoven fabric.

  Since the intermediate filtration nonwoven fabric is finer than the coarse filtration nonwoven fabric, at the end of winding of the cartridge filter (when the outer peripheral side is the upstream filtration side) or at the beginning of the winding (when the inner peripheral side is the upstream filtration side) than the coarse filtration nonwoven fabric It is preferable not to be located upstream of the filtration. This is because filtration with the coarsely filtered nonwoven fabric may be hindered by the intermediate filtered nonwoven fabric. Therefore, when placing the intermediate filtration nonwoven fabric, the length is shorter than the coarse filtration nonwoven fabric by the length corresponding to the number of windings of about 2 to 3 rounds, and the end of winding or the winding start position is the coarse filtration nonwoven fabric. It is preferable to shift to the downstream side.

  When using the said support nonwoven fabric, a support nonwoven fabric is piled up so that a support nonwoven fabric may be located in the filtration downstream rather than a laminated filtration nonwoven fabric and a coarse filtration nonwoven fabric, for example, and it winds around a core material. When using the net-like material, three layers are laminated and wound around the core material so that the net-like material is located between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric.

  FIG. 1 schematically shows an example of a method for producing the cartridge filter of the present invention. The method shown in FIG. 1 is a cartridge filter manufacturing method in which the inner peripheral side is the downstream side of filtration. The coarse filtration nonwoven fabric 10 has a predetermined length so that after a predetermined number of turns as a laminated filtration nonwoven fabric, the microfiltration nonwoven fabric 12 is wound a predetermined number of turns without being adjacent to each other. The microfiltration nonwoven fabric 12 has a predetermined length so that a predetermined number of turns are wound on the inner peripheral side, and the coarse filtration nonwoven fabric 12 is placed on the coarse filtration nonwoven fabric 10 so that one end thereof is positioned on the winding start side. Overlaid. The support nonwoven fabric 16 has a length larger than that of the coarse filtration nonwoven fabric. In FIG. 1, the support nonwoven fabric 16 is disposed below the coarse filtration nonwoven fabric 10 so that the support nonwoven fabric 16 is positioned on the outer peripheral side of the microfiltration nonwoven fabric 12 and the coarse filtration nonwoven fabric 10 when wound around the core material 14 once. ing.

  In FIG. 1, winding is started from a laminated body including the microfiltration nonwoven fabric 12, the coarse filtration nonwoven fabric 10, and the support nonwoven fabric 16, that is, the lamination filtration nonwoven fabric, and when a predetermined number of lamination filtration nonwoven fabrics are wound, 10 and the support nonwoven 16 are wound up. When the coarse filtration nonwoven fabric 10 is wound up, only the support nonwoven fabric 16 is wound several times (for example, about 1 to 5 laps) to form a cartridge filter. When the supporting nonwoven fabric includes heat-adhesive fibers, the supporting nonwoven fabric may be lightly heat-bonded at the end of winding.

  When the outer peripheral side is the filtration downstream side and the laminated filtration nonwoven fabric is wound on the outer periphery side, after the coarse filtration nonwoven fabric is wound, the fine filtration nonwoven fabric is supplied and the laminated filtration nonwoven fabric is arranged on the outer periphery side. After the laminated filtration nonwoven fabric is wound up, only the support nonwoven fabric is wound several times (for example, about 1 to 5 laps) to form a cartridge filter. When the supporting nonwoven fabric includes heat-adhesive fibers, the supporting nonwoven fabric may be lightly heat-bonded at the end of winding.

  Even when either side becomes the filtration downstream side, only the supporting nonwoven fabric may be wound around the core material several times before the filtration nonwoven fabric is wound around the core material. In that case, the laminated nonwoven fabric or the coarsely filtered nonwoven fabric is supplied after the supporting nonwoven fabric is wound several times (for example, about 1 to 5 turns).

  When using a net-like material and / or an intermediate filtration nonwoven fabric, as shown in FIG. 2, the net-like material 18 and / or the net-like material and / or the intermediate filtration nonwoven fabric and the coarse filtration nonwoven fabric are located. The intermediate filtration nonwoven fabric 20 is supplied. The net-like material 18 and / or the intermediate filtration nonwoven fabric 20 have the same length as the microfiltration nonwoven fabric 12 and may be stacked so as to coincide with the microfiltration nonwoven fabric 12. In some cases, the net 18 and / or the intermediate filtration nonwoven 20 is made longer or shorter than the microfiltration nonwoven 12 so that the net 18 and / or the intermediate filtration nonwoven 20 becomes the coarse filtration nonwoven 10 (and possibly this). And the supporting non-woven fabric 16) may be wound in the region in which the non-woven fabric is supported, or may be positioned between the microfiltration non-woven fabric 12 and the coarse filtration non-woven fabric 10 only in a part of the laminated filtration non-woven fabric. It's okay.

  The winding operation may be performed while applying heat. For example, when the supporting nonwoven fabric is a nonwoven fabric containing heat-adhesive fibers, a fiber web is used in place of the supporting nonwoven fabric in FIGS. The support nonwoven fabric may be produced by turning and immediately before winding or just before winding.

  In this way, after the laminated filtration nonwoven fabric and the coarse filtration nonwoven fabric, which are filter media, are wound to obtain a cylindrical body, the end face of the cylindrical body is heat-treated as necessary to obtain the cartridge filter of the present invention. it can. Further, the cartridge filter of the present invention may have a configuration in which a cylindrical body cover having holes through which fluid passes is provided on the outer side of a cylindrical body obtained by winding a filtration nonwoven fabric.

  The dimensions of the cartridge filter of the present invention are appropriately selected according to the application, and the core material, the thickness of each filtration nonwoven fabric, the number of turns of the laminated filtration nonwoven fabric and the coarse filtration nonwoven fabric, and in some cases, so as to obtain a desired dimension. The thickness etc. of the support nonwoven fabric used are selected. For example, the cartridge filter of the present invention has an outer diameter of 55 mm to 70 mm by winding a filtration nonwoven fabric around a core material having an inner diameter of about 25 mm to 35 mm, an outer diameter of about 35 mm to 50 mm, and a length of about 200 mm to 3000 mm. You may make it to the extent. The obtained cartridge filter may be cut to a desired length (for example, 200 mm to 800 mm).

  An example of the cartridge filter of the present invention is shown in FIG. The cartridge filter 100 of FIG. 3 is a cartridge filter whose outer peripheral side is the filtration upstream side and whose inner peripheral side is the filtration downstream side. Therefore, in this cartridge filter 100, the area 30 in which the laminated filtration nonwoven fabric of the support filtration nonwoven fabric 16 / the microfiltration nonwoven fabric 12 / the coarse filtration nonwoven fabric 10 is wound around the core material 14, the support filtration nonwoven fabric 16 / the coarse filtration nonwoven fabric. A region 32 around which 10 is wound is formed in order from the inner peripheral side. Further, only the support nonwoven fabric 16 is wound around the outermost peripheral region 34 of the cartridge filter 100 several times.

  The cartridge filter of the present invention achieves a high filtration accuracy (preferably a filtration accuracy of 0.7 μm is 90% or more, more preferably 95% or more) and a long filtration life. Preferably used in processing. In particular, the cartridge filter of the present invention is suitable for filtering semiconductor polishing liquid and drinking water. In such a field, a plurality of cartridge filters are used in series, and filtration is performed step by step from a coarse filter cartridge to a highly accurate cartridge filter. The present invention can be used as a cartridge filter at the final stage where the highest accuracy is required. The cartridge filter used in the final stage is required to have an accuracy of capturing 90% of 0.7 μm particles, for example.

Hereinafter, the present invention will be specifically described by way of examples.
In this example, the physical properties of each nonwoven fabric were measured according to the following methods.
[Thickness]
Using a micrometer (trade name: Coolant Proof Micrometer 293-230 MDC-25MJ: manufactured by Mitutoyo Corporation), the dimensions of any 10 points in the thickness direction of the nonwoven fabric were measured, and the average value was calculated. It was.

[Air permeability]
Measured according to JIS L 1096 8.27A (Fragile form method).

[90% filtration accuracy]
JIS11 seed powder is dispersed in water to prepare a test suspension, and the number (M) of each dust particle size contained in the test suspension and the target nonwoven fabric are coated with the test suspension. The particle size distribution measuring machine (trade name: Coulter Counter ZM type: Coulter Electronics Co., Ltd.) ). The blocking rate was calculated from the following formula for each particle size, and the particle size at which the blocking rate was 90% was defined as 90% filtration accuracy.
Blocking rate (%) = [(MN) × 100] / M

[Average flow pore size, maximum pore size, maximum pore size / minimum pore size]
Measurement was performed according to ASTM F 316-86 (bubble point method). The maximum pore size / minimum pore size was calculated by dividing the obtained maximum pore size value by the minimum pore size value.

[Average fiber diameter]
Using an electron microscope, the surface of the nonwoven fabric was magnified 100 to 1000 times and observed, and arbitrary 100 fiber side surfaces (widths) were measured, and the average value of the measured values was calculated. In addition, when the some fiber was melt | fused and the boundary was unknown, it measured considering the fiber group of the fused state as one fiber.

[CV value]
It calculated | required by the following Formula using the standard deviation and average fiber diameter of the fiber diameter which were measured similarly to the time of calculating | requiring an average fiber diameter.
CV value = (standard deviation / average fiber diameter) × 100

[Fraction rate]
The fiber diameter measured in the same manner as when calculating the average fiber diameter and the number of fibers of each fiber diameter were measured, and the fiber diameters occupied by 100 fibers were 0.5 μm or less, 1 μm or less, 4 μm or more, or 8 μm or more. The ratio of the number of fibers having a fiber diameter was determined. A fiber having a fiber diameter of 1 μm or less includes a fiber having a fiber diameter of 0.5 μm or less, and a fiber having a fiber diameter of 4 μm or more includes a fiber having a fiber diameter of 8 μm or more.

1. Preparation of filtration nonwoven fabric The following nonwoven fabric was prepared as a fine filtration nonwoven fabric and a coarse filtration nonwoven fabric.
(Microfiltration nonwoven fabric 1)
A melt-blown nonwoven fabric made of polypropylene with a basis weight of 15 g / m ² (trade name “Syntex-nano3”, manufactured by Mitsui Chemicals, Inc.)
(Microfiltration nonwoven fabric 2)
A melt-blown nonwoven fabric made of polypropylene with a basis weight of 15 g / m ² (trade name “H015UB-00F”, manufactured by Tapirs Co., Ltd.)
(Microfiltration nonwoven fabric 3)
Laminated nonwoven fabric with two microfiltration nonwoven fabrics 2

2. Preparation of coarse filtration nonwoven fabric As the coarse filtration nonwoven fabric, a melt blown nonwoven fabric (trade name “PO50FW-00F”, manufactured by Tapirs Co., Ltd.) made of polypropylene and having a basis weight of 50 g / m ² was prepared.

3. Preparation of intermediate filtration nonwoven fabric As an intermediate filtration nonwoven fabric, a melt blown nonwoven fabric (trade name “PO60UW-00F”, manufactured by Tapirs Co., Ltd.) made of polypropylene and having a basis weight of 60 g / m ² was prepared.
The physical properties of each microfiltration nonwoven fabric and coarse filtration nonwoven fabric are shown in Table 1.

4). Preparation of Net-like Material An extrusion net (trade name “Conweed Net R07107”, manufactured by JX Nippon Mining & Metals Corporation) made of polypropylene having a rectangular opening was prepared as a net-like material. Specifically, this net-like material had the following physical properties.
Diameter of the striatum 400μm
Opening shape and dimensions Vertical × horizontal rectangle of 4 mm × 5 mm (area 20 mm ² ) Thickness: 500 μm

5. Preparation of the core material The sheath / core is a high density polyethylene / polypropylene, and the volume ratio of the sheath / core is 5/5. H), manufactured by Daiwabo Polytech Co., Ltd., was used to produce a parallel card web having a basis weight of 33 g / m ^2. The web was heated for about 30 seconds with a hot air spraying device set at a temperature of 130 ° C. Polyethylene was melted or softened, and wound around a steel bar having an outer diameter of 30 mm in a state where the high-density polyethylene was melted or softened, and during the winding, pressure due to the weight of the iron bar and the wound web was continuously applied. Winding was performed until the outer diameter reached 42 mm to obtain a core material having a length of 600 mm.

6). Manufacture of cartridge filter (Example 1)
The microfiltration nonwoven fabric 1 was cut into a width of 60 cm and a length of 120 cm, and the coarse filtration nonwoven fabric was cut into a width of 60 cm and a length of 300 cm. As shown in FIG. 1, two nonwoven fabrics are supplied so that winding of the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric is started almost simultaneously, and further, a support nonwoven fabric in which fibers are thermally bonded by heating is supplied. However, these nonwoven fabrics were wound around the core material. As the supporting nonwoven fabric, the sheath / core is high-density polyethylene / polypropylene, the sheath / core volume ratio is 5/5, the fineness is 2.2 dtex (fiber diameter 18 μm), and the core-sheath type composite fiber (fiber length 51 mm) A non-woven fabric made of a parallel card web having a basis weight of 33 g / m ² and manufactured by using a trade name “NBF (H), manufactured by Daiwabo Polytech Co., Ltd.” and having fibers bonded together by a sheath component was used. After winding the coarsely filtered nonwoven fabric, it was further wound until the outer diameter became 65 mm, and the ends were lightly heat-bonded at the end of the winding.

  After the winding of the filtration nonwoven fabric, the length was cut to 250 mm, and the end face was heat-treated at 150 ° C. to obtain a cartridge filter. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound about 8 turns (8 to less than 9 turns) on the inner periphery side, and the coarse filtration nonwoven fabric is wound about 11 turns (11 turns to 12 turns on the outer periphery side). Less)) had a wound configuration.

(Example 2)
A cartridge filter was manufactured according to the same procedure as that adopted in Example 1 except that the length of the coarsely filtered nonwoven fabric was 400 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound on the inner peripheral side for about 8 turns (8 to less than 9 turns), and the coarse filtration nonwoven fabric is about 16 turns (16 to 17 turns on the outer periphery side). Less)) had a wound configuration.

(Example 3)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the length of the coarsely filtered nonwoven fabric was 500 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound on the inner circumference side for about 8 turns (8 to less than 9 turns), and the coarse filtration nonwoven cloth is about 21 turns (21 to 22 turns on the outer circumference side). Less)) had a wound configuration.

Example 4
A net-like material cut into a width of 60 cm and a length of 120 cm is supplied so as to be positioned between the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric, and the winding of the net-like material is a winding of the microfiltration nonwoven fabric and the coarse filtration nonwoven fabric. A cartridge filter was manufactured according to the same procedure as employed in Example 1 except that the procedure was started almost simultaneously. In the obtained cartridge filter, a laminated filtration nonwoven fabric (including a net) having a length of 120 cm is wound on the inner circumference side by about 8 turns (8 to less than 9 turns), and the coarse filtration nonwoven cloth is wound on the outer circumference side by about 9 turns ( 9 or more and less than 10 laps).

(Example 5)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the length of the coarsely filtered nonwoven fabric was 250 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound on the inner periphery side for about 8 turns (8 to less than 9 turns), and the coarse filter nonwoven fabric is about 8 turns (8 turns to 9 turns on the outer periphery side). Less)) had a wound configuration.

(Example 6)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the length of the microfiltration nonwoven fabric 1 was 70 cm and the length of the coarse filtration nonwoven fabric was 250 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 70 cm is wound on the inner peripheral side for about 5 turns (5 to less than 6 turns), and the coarse filtration nonwoven fabric is about 11 turns (11 to 12 turns on the outer periphery side). Less)) had a wound configuration.

(Example 7)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the length of the microfiltration nonwoven fabric 1 was 70 cm and the length of the coarse filtration nonwoven fabric was 300 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 70 cm is wound on the inner peripheral side for about 5 turns (5 to less than 6 turns), and the coarse filtration nonwoven fabric is about 14 turns (14 to 15 turns on the outer periphery side). Less)) had a wound configuration.

(Example 8)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the length of the microfiltration nonwoven fabric 1 was 70 cm and the length of the coarse filtration nonwoven fabric was 400 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 70 cm is wound on the inner circumference side for about 5 turns (5 to less than 6 turns), and the coarse filtration nonwoven cloth is about 19 turns (19 to 20 turns on the outer circumference side). Less)) had a wound configuration.

Example 9
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the length of the microfiltration nonwoven fabric 1 was 70 cm and the length of the coarse filtration nonwoven fabric was 500 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 70 cm is wound on the inner peripheral side for about 5 turns (5 to less than 6 turns), and the coarse filtration nonwoven fabric is about 25 turns (25 to 26 turns on the outer periphery side). Less)) had a wound configuration.

(Example 10)
The microfiltration nonwoven fabric 1 was cut into a width of 60 cm and a length of 120 cm, the intermediate filtration nonwoven fabric was cut into a width of 60 cm and a length of 210 cm, and the coarse filtration nonwoven fabric was cut into a width of 60 cm and a length of 250 cm. Three cores are supplied so that winding of the microfiltration nonwoven fabric, the intermediate filtration nonwoven fabric and the coarse filtration nonwoven fabric is started almost at the same time, and further, the support nonwoven fabric in which the fibers are thermally bonded to each other by heating is supplied. These nonwoven fabrics were wound around the material. The supporting nonwoven fabric was the same as the supporting nonwoven fabric used in Example 1. The support nonwoven fabric was wound around the coarsely filtered nonwoven fabric and then wound until the outer diameter reached 65 mm, and the ends were lightly heat-bonded at the end of the winding.

  After the winding of the filtration nonwoven fabric, the length was cut to 250 mm, and the end face was heat-treated at 150 ° C. to obtain a cartridge filter. The resulting cartridge filter has a laminated filtration nonwoven fabric (including an intermediate filtration nonwoven fabric) having a length of 120 cm wound on the inner circumference side for about 8 turns (8 to less than 9 turns), and the coarse filtration nonwoven cloth is placed on the outer circumference side. 7 rounds (7 rounds or more and less than 8 rounds) were wound, and about 5 rounds (5 rounds or more and less than 6 rounds) were wound together with the intermediate filtration nonwoven fabric.

(Example 11)
A net-like material cut into a width of 60 cm and a length of 210 cm is supplied so as to be positioned between the microfiltration nonwoven fabric and the intermediate filtration nonwoven fabric, and the winding of the net-like material is a microfiltration nonwoven fabric, an intermediate filtration nonwoven fabric and a coarse filtration. A cartridge filter was manufactured according to the same procedure as that employed in Example 10, except that it was started almost simultaneously with the winding of the nonwoven fabric. The obtained cartridge filter has a laminated filtration nonwoven fabric (including an intermediate filtration nonwoven fabric and a net) having a length of 120 cm wound on the inner peripheral side, and is wound about 7 turns (7 to less than 8 turns), and the coarse filtration nonwoven cloth is placed on the outer peripheral side. Was wound about 6 rounds (6 rounds or more and less than 7 rounds), of which about 4 rounds (4 rounds or more and less than 5 rounds) were wound together with the net-like material and the intermediate filtration nonwoven fabric.

(Example 12)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the microfiltration nonwoven fabric 3 was used instead of the microfiltration nonwoven fabric. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound on the inner circumference side for about 8 turns (8 to less than 9 turns), and the coarse filtration nonwoven fabric is about 10 turns (10 to 11 turns on the outer circumference side). Less)) had a wound configuration.

(Example 13)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the microfiltration nonwoven fabric 3 was used instead of the microfiltration nonwoven fabric, and the length of the coarse filtration nonwoven fabric was 500 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound on the inner circumference side for about 8 turns (8 to less than 9 turns), and the coarse filtration nonwoven cloth is about 21 turns (21 to 22 turns on the outer circumference side). Less)) had a wound configuration.

(Example 14)
The same procedure as used in Example 1 except that the microfiltration nonwoven fabric 3 was used in place of the microfiltration nonwoven fabric, the length was 70 cm, and the length of the coarse filtration nonwoven fabric was 400 cm. A cartridge filter was manufactured according to In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 70 cm is wound on the inner circumference side for about 5 turns (5 to less than 6 turns), and the coarse filtration nonwoven cloth is about 19 turns (19 to 20 turns on the outer circumference side). Less)) had a wound configuration.

(Comparative Example 1)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that only the microfiltration nonwoven fabric 1 was used. The obtained cartridge filter had a configuration in which only a microfiltration nonwoven fabric having a length of 120 cm was wound about 8 turns (more than 8 turns and less than 9 turns).

(Comparative Example 2)
A cartridge filter was manufactured according to the same procedure as that adopted in Example 1 except that the length of the coarsely filtered nonwoven fabric was 180 cm. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound on the inner peripheral side for about 8 turns (8 to less than 9 turns), and the coarse filtration nonwoven fabric is about 3 turns (3 to 4 turns on the outer periphery side). Less)) had a wound configuration.

(Comparative Example 3)
A cartridge filter was manufactured according to the same procedure as that employed in Example 1 except that the microfiltration nonwoven fabric 2 was used instead of the microfiltration nonwoven fabric 1. In the obtained cartridge filter, a laminated filtration nonwoven fabric having a length of 120 cm is wound about 8 turns (8 to less than 9 turns) on the inner periphery side, and the coarse filtration nonwoven fabric is wound about 11 turns (11 turns to 12 turns on the outer periphery side). Less)) had a wound configuration.

  The performance of the cartridge filters obtained in Examples 1 to 12 and Comparative Examples 1 to 3 was evaluated by measuring 0.7 μm filtration accuracy and filtration life. The evaluation results are shown in Table 2. The evaluation method is as follows.

[0.7μm filtration accuracy]
A test suspension according to JIS Z8901 (JIS 11 species) is dispersed in water to prepare a test suspension, and the number (M) of the dust contained in the test suspension for each particle size (M) and the suspension for the test are prepared. The turbid liquid was filtered through the target cartridge filter at a flow rate of 40 liters / minute from the outer peripheral side to the inner peripheral side of the cartridge filter. Was measured using a particle size distribution analyzer (trade name: Coulter Counter ZM type: manufactured by Coulter Electronics Co., Ltd.). The blocking rate was calculated from the following formula for each particle size, and the rate of blocking particles having a particle size of 0.7 μm or more was defined as 0.7 μm filtration accuracy.
Blocking rate (%) = [(MN) × 100] / M

[Filtration life]
Test dust (JIS 11 species) according to JIS Z8901 was dispersed in water to prepare a test suspension having a concentration of 50 ppm. Next, the test suspension is allowed to pass at a flow rate of 40 liters / minute from the outer peripheral side of the cartridge filter toward the inner peripheral side hollow portion while stirring uniformly, and the liquid passing pressure for maintaining this flow rate is 0. The total liquid flow rate (liter) when the pressure reached 2 MPa was defined as the filtration life.

  In each of Examples 1 to 4 and 10 to 14, the filtration accuracy of 0.7 μm exceeded 90% and the filtration life was 200 liters or more, and both high filtration accuracy and a long filtration life were achieved. In particular, Examples 10 and 11 had very high filtration accuracy. This is considered to be due to winding the intermediate filtration layer nonwoven fabric. Since Example 3, Example 9 and Example 13 had the coarse filtration nonwoven fabric wound more than 20 times, they had a longer filtration life compared to Example 1, Example 6 and Example 12, respectively. It was. In addition, Example 11 had a longer filtration life than Example 10. This is recognized as a net effect.

  Examples 6, 7, 8, and 9 had lower 0.7 μm filtration accuracy when compared to Examples 5, 1, 2, and 4, respectively. This is thought to be because the number of windings of the microfiltration nonwoven fabric is small. However, also in these Examples, a 0.7 μm filtration accuracy of 93% or more could be secured, and a high filtration life could be secured.

  Since the area | region where the coarse filtration nonwoven fabric was wound is not formed in the comparative example 1 in the filtration upstream, the filtration lifetime became short. In Comparative Example 2, a region in which the coarse filtration nonwoven fabric was wound was formed on the upstream side of the filtration, but the filtration life could not be extended because the number of turns of the coarse filtration nonwoven fabric was small. In Comparative Example 3 using a nonwoven fabric with 90% filtration accuracy exceeding 4 μm as the microfiltration nonwoven fabric, the 0.7 μm filtration accuracy was less than 90%, and sufficient filtration accuracy could not be obtained.

  The cartridge filter of the present invention realizes high filtration accuracy and a long filtration life, and is suitable for various uses for removing solids from a fluid. For example, pure water, drinking water, chemicals, various oils and fats, plating solutions It is suitable for filtering fluids such as paint solutions or electronic industry cleaning water, especially semiconductor cleaning fluids.

DESCRIPTION OF SYMBOLS 10 Rough filtration nonwoven fabric 12 Microfiltration nonwoven fabric 14 Core material 16 Support nonwoven fabric 18 Net-like material 20 Intermediate filtration nonwoven fabric 30 Support filtration nonwoven fabric / microfiltration nonwoven fabric / Rough filtration nonwoven fabric area 32 Support filtration nonwoven fabric / rough filtration nonwoven fabric wound Rotated area 34 Area where support filtration nonwoven fabric is wound 100 Cartridge filter

Claims (4)

A cartridge filter in which a filtration nonwoven fabric is wound around a tubular core material having holes through which a fluid passes,
A 90% filtration accuracy is 4 μm or more and less than 10 μm, and a coarse filtration nonwoven fabric having an air permeability of ² cc / cm ² / second to 30 cc / cm ² / second is wound 7 or more times on the upstream side of the filtration,
A laminated filtration nonwoven fabric comprising a fine filtration nonwoven fabric having a 90% filtration accuracy of 0.5 μm or more and less than 4 μm and an air permeability of ² cc / cm ² / second to 30 cc / cm ² / second and the coarse filtration nonwoven fabric is filtered. Wound more than one turn on the downstream side,
Cartridge filter.   The cartridge filter according to claim 1, wherein the microfiltration nonwoven fabric is a meltblown nonwoven fabric having a CV value of 60 to 200. Microfiltration nonwoven, cartridge filter according to claim 1 or 2 basis weight is ^5g / ^{m 2 ~40g} / m 2   The cartridge filter according to any one of claims 1 to 3, wherein a supporting nonwoven fabric having a 90% filtration accuracy of 10 µm or more is wound together with a laminated filtration nonwoven fabric and a coarse filtration nonwoven fabric.

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