JP7021412B2 - Cartridge filter - Google Patents

Description

The present invention relates to a pleated type cartridge filter suitable for filtering liquids such as beverages, chemicals, oils and fats, paints, and industrial cleaning waters such as cleaning waters for electronic parts and semiconductor products.

As a cartridge filter that filters fluid and collects foreign matter, a pleated type cartridge filter in which a filter medium is folded into a pleated shape, a tubular filter in which a fiber aggregate is wound in a tubular shape, and the like are used. Various filters such as pleated type cartridge filters and tubular filters are designed to capture foreign substances in order from the largest size in order to efficiently capture foreign substances contained in the fluid (liquid or gas) to be filtered. ing. Specifically, various types of filters are manufactured by combining several types of fiber aggregates such as non-woven fabrics, woven and knitted fabrics, and nets composed of monofilaments. Is placed on the side where the object to be filtered flows in (also referred to as the upstream side, the primary side, or simply the inflow side), and the side where the object to be filtered flows out (downstream side, the secondary side, or simply the outflow side). A dense fiber aggregate smaller than the average fiber diameter or average pore diameter, that is, fine-grained, is placed in). In this way, in a filter that combines several types of different fiber aggregates, the fiber aggregates are arranged so that the average fiber diameter and the average pore size gradually decrease from the inflow side to the outflow side. , The fiber aggregate having the smallest average fiber diameter and average pore size is used as a substantial final filtration layer. With such a structure, foreign matter can be captured in order from the largest foreign matter, and it has been considered that foreign matter is captured in each fiber aggregate according to its average fiber diameter and average pore diameter. .. For example, Patent Document 1 describes a pleated filter in which a fiber forming a pleated type filter medium is imparted with a fiber diameter gradient from a surface layer portion to a back layer portion. Further, Patent Document 2 describes a filter element in which a filter medium for a filter having a low density on the upstream side and a high density on the downstream side is bent by alternately repeating mountain folds and valley folds.

Japanese Unexamined Patent Publication No. 11-90135 Japanese Unexamined Patent Publication No. 2009-297656

However, the filters described in Patent Documents 1 and 2 are required to further improve the efficiency of capturing foreign substances. Among them, paints, especially color resists used for color filters constituting various displays, remove residues, by-products, and mixed foreign substances after synthesizing dyes, but some of the residues and by-products are gel-like. There is a foreign substance in. Since gel-like foreign matter is deformed by the pressure during filtration, even after being trapped by the filter material once, it is deformed by the pressure, slips through the network structure of the filter material, and is remixed into the fluid after the filtration process. There is. Color resists mixed with gel-like foreign matter deteriorate the processability during color filter manufacturing, and cause problems with the finished color filter and the display using it, so gel-like foreign matter is removed with higher accuracy. A filter is required.

The present invention provides a cartridge filter having improved foreign matter trapping efficiency and high filtration performance in order to solve the above-mentioned conventional problems.

The present invention is a cartridge filter in which the filter material is folded into a pleated shape, and the filter material has a first fiber layer, and a second fiber layer and a first net are on the inflow side of the first fiber layer. , And any one selected from the group consisting of the laminated body of the first net and the second fiber layer is arranged, and the laminated body of the first net and the second fiber layer is arranged on the inflow side of the first fiber layer. In this case, the first net and the second fiber layer are arranged in this order from the inflow side, and the third fiber layer is arranged on the outflow side of the first fiber layer, and the average pore size of the first fiber layer is 0. It is 5 to 20 μm, the average pore diameter of the third fiber layer is 3 to 25 μm, and the average pore diameter of the third fiber layer is 1.1 to 8 times the average pore diameter of the first fiber layer, which constitutes the above-mentioned filter material. The present invention relates to a cartridge filter in which the fiber layer having the smallest average pore diameter is the first fiber layer in all the fiber layers.

In the cartridge filter, it is preferable that the fourth fiber layer is further arranged on the outflow side of the third fiber layer, the average pore size of the fourth fiber layer is 5 to 60 μm, and the average pore size of the fourth fiber layer. However, it is preferable that the average pore size of the third fiber layer is 1.05 to 4 times. Further, it is preferable that the filter material has a second net, and the second net is arranged on the most outflow side among the fiber aggregates constituting the filter material.

In the cartridge filter, the number of fiber layers constituting the filter material is 2 to 6, and the fiber layers arranged on the inflow side of the first fiber layer are 0 to 2 layers, which is the first fiber layer. The fiber layers arranged on the outflow side are 1 to 3 layers, and the number of fiber layers arranged on the outflow side of the first fiber layer and the number of fiber layers arranged on the inflow side of the first fiber layer. It is preferable that the number of fiber layers arranged on the outflow side of the first fiber layer is equal to or greater than the number of fiber layers arranged on the inflow side of the first fiber layer.

In the cartridge filter, on the inflow side of the first fiber layer, only one selected from the group consisting of the second fiber layer, the first net, and the laminate of the first net and the second fiber layer is arranged. It is preferable to have.

In the cartridge filter, the second fiber layer or the laminated body of the first net and the second fiber layer is arranged on the inflow side of the first fiber layer, and the average pore diameter of the second fiber layer is 5 to 60 μm. The average pore diameter of the second fiber layer is preferably 3 to 10 times the average pore diameter of the first fiber layer. Further, the average pore diameter of the second fiber layer is preferably 1.05 to 4 times the average pore diameter of the third fiber layer.

INDUSTRIAL APPLICABILITY The present invention can provide a pleated type cartridge filter having improved foreign matter trapping efficiency and high filtration performance.

Generally, in a pleated type cartridge filter or a tubular filter in which a fiber aggregate is wound in a tubular shape, the fiber aggregate is gradually reduced in average fiber diameter and average pore diameter from the inflow side to the outflow side. Are laminated and arranged, and the fiber aggregate having the smallest average fiber diameter and average pore size is used as the final filtration layer. As a result of diligent studies on the phenomenon that foreign matter remains in the filtrate when a conventional pleated type cartridge filter is used, the inventor of the present invention has found that the fiber layer having the smallest average pore size (hereinafter referred to as the finest fiber layer). (Also also referred to as)) is not used as the final filtration layer, but the finest fiber layer is arranged on the upstream side to some extent, and then the fiber layer, net, which is larger than the average pore size of the finest fiber layer on the inflow side and the outflow side of the finest fiber layer. Alternatively, they have found that by arranging a laminate thereof, the efficiency of capturing foreign substances is improved and the filtration performance is improved, and the present invention has been made.

The present invention is a pleated type cartridge filter in which the filter material is folded into a pleated shape. The filter medium has a first fiber layer, and is selected from the group consisting of a second fiber layer, a first net, and a laminate of the first net and the second fiber layer on the inflow side of the first fiber layer. One of them is arranged, and the third fiber layer is arranged on the outflow side of the first fiber layer. In the present invention, when the laminate of the first net and the second fiber layer is arranged on the inflow side of the first fiber layer, the first net and the second fiber layer are arranged in this order from the inflow side. .. The average pore diameter of the first fiber layer is 0.5 to 20 μm, the average pore diameter of the third fiber layer is 3 to 25 μm, and the average pore diameter of the third fiber layer is 1.1 with respect to the average pore diameter of the first fiber layer. It is ~ 8.0 times. As will be described later, the filter medium may contain other fiber layers in addition to the first fiber layer, the second fiber layer, and the third fiber layer, and in all the fiber layers constituting the filter material, the first fiber layer is used. The average pore size of the fiber layer is the smallest.

In the present invention, the fiber layer means a fiber aggregate composed of fibers or threads having an average fiber diameter of 500 μm or less. Further, in the present invention, the net is a fiber aggregate composed of fibers having a fiber length of 120 mm or more (including substantially continuous fibers, that is, monofilaments and multifilaments), and regular voids due to the constituent fibers. Means a fiber aggregate having a thickness of 120 μm or more as measured by the measuring method described later. For example, even a fiber aggregate in which long fibers including Milife (registered trademark) and Warif (registered trademark) sold by JX Nikko Nisseki Energy Co., Ltd. are oriented in the vertical and horizontal directions has a thickness of less than 120 μm. Those having an average fiber diameter of 500 μm or less correspond to the fiber layer, and those having an average fiber diameter of 500 μm or less do not correspond to the net of the present invention. Further, although non-woven fabrics composed of long fibers, for example, spunbonded nonwoven fabrics and meltblown nonwoven fabrics having a thickness of 120 μm or more exist, they do not fall under the net of the present invention because regular voids are not formed. If the fiber aggregate meets the requirements of both the fiber layer and the net, it is regarded as a net.

In the cartridge filter of the present invention, it is preferable that the fourth fiber layer is arranged on the outflow side of the third fiber layer from the viewpoint of further improving the filtration accuracy. It is preferable that the average pore diameter of the fourth fiber layer is 5 to 60 μm, and the average pore diameter of the fourth fiber layer is 1.05 to 4 times the average pore diameter of the third fiber layer. Further, from the viewpoint of imparting strength, it is preferable that the second net is arranged on the most outflow side among the fiber aggregates constituting the filter material.

When the cartridge filter of the present invention contains the second fiber layer on the inflow side of the first fiber layer, the average pore size of the second fiber layer is 5 to 60 μm, and the average pore size of the second fiber layer is that of the first fiber layer. It is preferably 3 to 10 times the average pore size. The average pore diameter of the second fiber layer is more preferably 1.05 to 4 times the average pore diameter of the third fiber layer.

In the filtration using the pleated type cartridge filter of the present invention, most of the foreign matter is captured when the object to be filtered passes through the first fiber layer having the smallest average pore size among the fiber layers constituting the filter material. Guessed. Among the foreign substances contained in the object to be filtered, there are foreign substances that pass through the first fiber layer and gel-like foreign substances that are once captured by the first fiber layer but pass through the first fiber layer due to deformation. However, when the object to be filtered containing foreign matter passes through the first fiber layer, its pressure is buffered and the flow velocity decreases. As a result, foreign matter that has passed through the first fiber layer is captured by the third fiber layer, which is arranged on the outflow side of the first fiber layer and has an average pore diameter larger than that of the first fiber layer but has sufficient foreign matter trapping property. It is considered that this suppresses the removal of foreign matter and improves the ability to catch foreign matter. On the upstream side of the first fiber layer, a second fiber layer having an average pore diameter larger than the average pore diameter of the first fiber layer, or a laminate of a second fiber layer having an average pore diameter larger than the average pore diameter of the first fiber layer and a first net. When is arranged, the foreign matter catching performance is further improved.

The second fiber layer is a fiber layer arranged on the upstream side of the first fiber layer, and is used alone or laminated with the first net. When both the second fiber layer and the first net are arranged on the upstream side of the first fiber layer, they are arranged so as to be the first net and the second fiber layer in order from the inflow side of the filter material, and the second fiber layer. Is preferably arranged adjacent to the first fiber layer. The second fiber layer is a fiber layer provided as needed, and in some cases, the second fiber layer may not be used and only the first net may be provided on the upstream side of the first fiber layer. The second fiber layer has a role of capturing relatively large foreign substances contained in the fluid. Therefore, the average pore diameter of the second fiber layer may be larger than the average pore diameter of the first fiber layer, and is not particularly limited, but is preferably 3 to 10 times the average pore diameter of the first fiber layer, and is preferably 3 to 8 times. It is more preferably double, further preferably 3.4 to 8 times, even more preferably 3.4 to 6.8 times, and further preferably 3.5 to 6.8 times. It is more preferable, and it is even more preferable that it is 4 to 6.8 times.

The third fiber layer is a fiber layer arranged on the downstream side of the first fiber layer, and has a role of capturing foreign matter that has passed through the first fiber layer. Therefore, the average pore diameter of the third fiber layer is larger than the average pore diameter of the first fiber layer, but the average pore diameter capable of capturing foreign matter, that is, the average pore diameter is required to be small to some extent. The average pore size of the third fiber layer may be 1.1 to 8 times the average pore size of the first fiber layer, but is preferably 1.4 to 8 times, and preferably 2 to 6 times. It is more preferably 2.3 to 5.8 times, further preferably 3 to 5.6 times, and even more preferably 3 to 5.6 times.

The fourth fiber layer is a fiber layer provided as needed, and is arranged on the outflow side of the third fiber layer so as to be adjacent to the third fiber layer. In a pleated type cartridge filter, if a fiber layer having an average pore diameter too small is present on the downstream side, not only the pressure loss may be large, but also the flow rate of the fluid to be filtered may be extremely reduced. Therefore, it is preferable that the average pore diameter of the fourth fiber layer is larger than the average pore diameter of the first fiber layer, and the average pore diameter is relatively large among the fiber layers constituting the filter material. The average pore size of the fourth fiber layer is preferably 3 to 10 times, more preferably 3 to 8 times, and even more preferably 3.2 to 8 times the average pore size of the first fiber layer. It is even more preferably 3.2 to 6.8 times, even more preferably 3.5 to 6.8 times, and even more preferably 4 to 6.8 times. Further, the average pore diameter of the fourth fiber layer is preferably larger than the average pore diameter of the third fiber layer.

In the above-mentioned filter material, the fiber layers such as the first fiber layer, the second fiber layer, the third fiber layer, and the fourth fiber layer are fiber aggregates in which the average fiber diameter of the fibers or threads constituting the fiber layer is 500 μm or less. It may be a thing, and is not particularly limited. Examples of the fiber layer include non-woven fabrics, knitted fabrics, and woven fabrics. It is preferable to use a non-woven fabric in which the fibers constituting the fiber layer form a three-dimensional network structure and the foreign matter trapping performance is easily improved by the deep filtration mechanism depending on the thickness.

Hereinafter, the case where each fiber layer is a non-woven fabric will be described as an example.

The above-mentioned non-woven fabric is not particularly limited, and is spunbonded non-woven fabric, needle punched non-woven fabric, water flow entangled non-woven fabric, heat-bonded non-woven fabric (also referred to as thermal bond non-woven fabric or air-through non-woven fabric), wet non-woven fabric, melt blown non-woven fabric, electrospinning method (electrostatic spinning method). ) Can be used, but a melt blown non-woven fabric is preferable. The melt blown non-woven fabric produced by the melt blow method is easier to obtain a non-woven fabric having a smaller pore diameter than other non-woven fabrics, and has a high basis weight uniformity.

The resin used for the melt blown non-woven fabric is not limited, and is limited to polyolefin resins such as polypropylene and polyethylene, polyester resins such as polyethylene terephthalate and polytrimethylene terephthalate, and polyamide resins such as nylon 6 and nylon-6,6. Any type of resin can be used as long as it can produce a meltblown non-woven fabric. Among them, a meltblown nonwoven fabric made of a polyolefin fiber using a polyolefin resin is preferable, a meltblown nonwoven fabric made of a polypropylene fiber is more preferable, and a meltblown nonwoven fabric made of a polypropylene single fiber (PP fiber) is more preferable. Is more preferable, but there is no particular problem even if it is a composite fiber. Since polypropylene has high chemical resistance, it can be used for filtration of various types of liquids, and it is preferable because it has a low softening point and a low melting point and is excellent in heat workability.

The first fiber layer is preferably a meltblown nonwoven fabric, more preferably one surface of the meltblown nonwoven fabric is smoothed, and particularly preferably both surfaces are smoothed. The term "smoothing" as used herein means that the surface of the nonwoven fabric is smoothed into a porous film by subjecting at least one surface of the meltblown nonwoven fabric to a calendar process using, for example, a thermal roll. By calendaring at least one surface of the melt-blown non-woven fabric, particularly preferably both surfaces, with a thermal roll, the smoothed surface of the melt-blown non-woven fabric becomes a porous film, and the entire melt-blown non-woven fabric becomes dense, and the average pore size becomes large. Can be made smaller. As described above, the meltblown nonwoven fabric having at least one surface smoothed can be preferably used as the first fiber layer. Further, by adjusting the smoothing conditions, it can also be used as another fiber layer, for example, a third fiber layer.

The first fiber layer has an average pore diameter of 0.5 to 20 μm, preferably 1 to 14 μm, more preferably 1.5 to 9 μm, and preferably 1.8 to 7.5 μm. It is even more preferably 1.8 to 5.4 μm, even more preferably. The average pore size of the first fiber layer can be selected in consideration of the desired filtration accuracy, and when used in applications requiring high filtration accuracy, the average pore size of the first fiber layer is preferably 1.8 to 5 μm. It is more preferably 1.8 to 4.5 μm, and even more preferably 1.8 to 4 μm. Further, if the application does not require high filtration accuracy, the average pore size of the first fiber layer may be 3 to 6.5 μm or 3.5 to 6.5 μm. When the average pore diameter of the first fiber layer is within the above range, the pressure of the object to be filtered after passing through the first fiber layer tends to be low, and the filtration accuracy of the cartridge filter is high.

The maximum pore diameter of the first fiber layer is preferably 1 to 70 μm, more preferably 2 to 30 μm, further preferably 2 to 20 μm, still more preferably 3 to 18 μm, and 4 Even more preferably, it is ~ 16 μm. The maximum pore size of the first fiber layer can be selected in consideration of the desired filtration accuracy, and when used in an application requiring high filtration accuracy, the maximum pore size of the first fiber layer is preferably 4 to 10 μm. Further, if the application does not require high filtration accuracy, the maximum pore size of the first fiber layer may be 10 to 18 μm. Further, the first fiber layer preferably has a maximum porous diameter of 0.5 to 28 μm, more preferably 1.0 to 20 μm, still more preferably 1.5 to 12 μm, and 1.8 to 1.8 to 12 μm. Even more preferably, it is 8 μm. The minimum pore diameter of the first fiber layer is preferably 0.1 to 27 μm, more preferably 0.3 to 20 μm, further preferably 0.5 to 10 μm, and further preferably 0.8 to 0.8 to. Even more preferably, it is 6 μm. When the maximum pore diameter, the maximum pore diameter and the minimum pore diameter of the first fiber layer are within the above ranges, the flow velocity of the object to be filtered after passing through the first fiber layer decreases, and the filtration accuracy of the cartridge filter becomes higher.

The second fiber layer and the fourth fiber layer preferably have an average pore diameter of 5 to 60 μm, more preferably 8 to 50 μm, further preferably 10 to 32 μm, and further preferably 12 to 25 μm. Even more preferable. When the average pore diameters of the second fiber layer and the fourth fiber layer are within the above range, the second fiber layer becomes more effective as the prefiltration layer of the first fiber layer, and the fourth fiber layer captures a certain amount of foreign matter. It is possible to suppress the influence on the pressure and flow rate of the fluid to be filtered while maintaining the ability to do so. The maximum pore diameter of the second fiber layer and the fourth fiber layer is preferably 15 to 80 μm, more preferably 20 to 50 μm, further preferably 25 to 35 μm, and even more preferably 26 to 32 μm. Is even more preferable. The maximum porous diameter of the second fiber layer and the fourth fiber layer is preferably 5 to 30 μm, more preferably 8 to 28 μm, further preferably 12 to 24 μm, and further preferably 14 to 20 μm. More preferred. The minimum pore diameter of the second fiber layer and the fourth fiber layer is preferably 5 to 25 μm, more preferably 8 to 20 μm, further preferably 10 to 16 μm, and further preferably 12 to 15 μm. More preferred. When the maximum pore diameter, the maximum pore diameter and the minimum pore diameter of the second fiber layer and the fourth fiber layer are within the above ranges, the effects of the second fiber layer and the fourth fiber layer described above are enhanced, and the filtration accuracy of the cartridge filter is enhanced. Will be higher.

The average pore diameter of the third fiber layer may be 3 to 25 μm, preferably 5 to 20 μm, more preferably 8 to 18 μm, and even more preferably 10 to 16 μm. When the average pore diameter of the third fiber layer is within the above range, the third fiber layer easily catches foreign matter, and there is little influence such as a decrease in pressure or flow velocity of the object to be filtered. The maximum pore diameter of the third fiber layer is preferably 10 to 50 μm, more preferably 15 to 30 μm, further preferably 18 to 26 μm, and even more preferably 20 to 24 μm. The most porous diameter of the third fiber layer is preferably 3 to 20 μm, more preferably 5 to 18 μm, further preferably 8 to 15 μm, and even more preferably 9 to 13 μm. The minimum pore diameter of the third fiber layer is preferably 1 to 20 μm, more preferably 3 to 15 μm, further preferably 5 to 12 μm, and even more preferably 6 to 10 μm. When the maximum pore diameter, the maximum pore diameter and the minimum pore diameter of the third fiber layer are within the above ranges, the efficiency of capturing foreign matter tends to be high while suppressing the influence of the third fiber layer on the pressure and flow rate of the fluid to be filtered.

The average pore size of the second fiber layer and the fourth fiber layer is preferably 1.05 to 4 times, more preferably 1.1 to 3 times, the average pore size of the third fiber layer. It is more preferably .15 to 2.5 times, and even more preferably 1.2 to 2.2 times. When the average pore diameter of the second fiber layer and the fourth fiber layer becomes the above ratio with respect to the average pore diameter of the third fiber layer, the pleated type cartridge filter of the present invention has a long filtration life. When the average pore diameters of the second fiber layer, the third fiber layer, and the fourth fiber layer satisfy the above range as a magnification with respect to the average pore diameter of the first fiber layer, the efficiency of capturing foreign matter is improved and the cartridge filter is used. The filtration performance of is higher. The method for measuring the average pore diameter, the maximum pore diameter, the maximum pore diameter and the minimum pore diameter of the non-woven fabric will be described later.

The first fiber layer, the second fiber layer, the third fiber layer and the fourth fiber layer preferably have an average fiber diameter of 0.5 to 20 μm, more preferably 1 to 10 μm, and 1.5 to 1. It is even more preferably 8.5 μm, and even more preferably 1.8 to 5 μm. In particular, the average fiber diameter of the first fiber layer can be selected in consideration of the desired filtration accuracy, and when used in applications requiring high filtration accuracy, the average fiber diameter of the first fiber layer is 1.8 to 5 μm. It is preferable to have. Further, if the application does not require high filtration accuracy, the average fiber diameter of the first fiber layer may be 3 to 9.5 μm. The minimum fiber diameter of the first fiber layer, the second fiber layer, the third fiber layer and the fourth fiber layer is preferably 0.03 to 5 μm, more preferably 0.05 to 3 μm, and 0. It is even more preferably 05 to 2 μm, even more preferably 0.08 to 1.5 μm, even more preferably 0.08 to 1 μm, and even more preferably 0.1 to 0.8 μm. preferable. The first fiber layer, the second fiber layer, the third fiber layer and the fourth fiber layer preferably have a maximum fiber diameter of 3 to 50 μm, more preferably 3 to 30 μm, and 5 to 25 μm. Is even more preferable, and 5 to 20 μm is even more preferable. When the average fiber diameter, the minimum fiber diameter and the maximum fiber diameter of the first fiber layer, the second fiber layer, the third fiber layer and the fourth fiber layer satisfy the above ranges, the filtration performance of the cartridge filter becomes higher. The method for measuring the average fiber diameter, the minimum fiber diameter and the maximum fiber diameter will be described later.

In the cartridge filter of the present invention, the first fiber layer and the third fiber layer constituting the filter material determine the filtration accuracy of the cartridge filter, that is, how small the size of the cartridge filter sufficiently captures foreign matter. It is a layer. Therefore, it is preferable that the first fiber layer and the third fiber layer are high-weight fiber layers from which a fiber layer having a small average pore size can be easily obtained. The basis weight of the first fiber layer and the third fiber layer is preferably in the range of 30 to 150 g / m ² , more preferably in the range of 35 to 120 g / m ² , and more preferably 40 to 100 g / m 2.
It is more preferably within the range of m ² . When the basis weights of the first fiber layer and the third fiber layer satisfy the above range, the filtration performance of the obtained cartridge filter can be improved. The basis weight of the first fiber layer is particularly preferably in the range of 60 to 90 g / m ² , and the basis weight of the third fiber layer is particularly preferably in the range of 40 to 70 g / m ² .

In the cartridge filter of the present invention, the second fiber layer and the fourth fiber layer constituting the filter material are the pre-filter layer (second fiber layer) of the first fiber layer, or the fiber layer located on the relatively downstream side. Since it may be (fourth fiber layer), it is preferable that the fiber layer has a low grain size and a fiber layer having a large average pore diameter can be easily obtained. The basis weight of the second fiber layer and the fourth fiber layer is preferably in the range of 5 to 100 g / m ² , more preferably in the range of 20 to 80 g / m ² , and 25 to 70 g / m ² . It is more preferably within the range. When the basis weights of the second fiber layer and the fourth fiber layer satisfy the above range, not only the filtration performance of the obtained cartridge filter can be improved, but also the so-called cartridge filter having a long filtration life, which can perform the filtration process for a long time, can be obtained. Obtainable. The basis weight of the second fiber layer is particularly preferably in the range of 20 to 40 g / m ² , and the basis weight of the fourth fiber layer is particularly preferably in the range of 40 to 70 g / m ² .

By appropriately reducing the flow velocity of the liquid to be filtered, the efficiency of capturing foreign substances is improved, and a cartridge filter with high filtration performance can be easily obtained. Therefore, the basis weight of the first fiber layer constitutes the filter material. It is preferably the largest of the fiber layers to be formed. Further, from the viewpoint of capturing a relatively large foreign substance with respect to the liquid to be filtered without causing a sharp decrease in flow rate or pressure, the basis weight of the second fiber layer is among the fiber layers constituting the filter material. The smallest is preferable. The method of measuring the basis weight will be described later.

The thickness of the first fiber layer is not particularly limited. However, the thickness of the first fiber layer is within the range of 0.08 to 0.8 mm from the viewpoint that the first fiber layer affects the filtration accuracy and that the fiber aggregate having a small average pore size is used as the first fiber layer. It is preferably in the range of 0.1 to 0.4 mm, more preferably in the range of 0.15 to 0.35 mm, and even more preferably in the range of 0.15 to 0.35 mm. When the thickness of the first fiber layer is 0.08 mm or more, the first fiber layer does not become too thin, and the first fiber layer is less likely to be damaged when producing a cartridge filter or when using the cartridge filter. However, by ensuring the thickness of the fiber aggregate, a fiber layer having a small average pore diameter is likely to be formed, and the filtration performance of the cartridge filter can be further improved. Further, when the thickness of these fiber aggregates is 0.8 mm or less, the first fiber layer is not excessively thick, that is, the fiber aggregate has a small average pore diameter and a high density. Therefore, this is also a cartridge filter. Filtration performance can be improved. The method for measuring the thickness of the non-woven fabric will be described later.

When the first fiber layer satisfies the above range of basis weight and thickness, the fiber layer has a high density. When the density of the first fiber layer is high to some extent, the structure of the nonwoven fabric becomes dense, and the fiber layer has a small average pore size. A cartridge filter using this will have high filtration accuracy. The density of the first fiber layer is preferably 0.12 to 0.8 g / cm ³ , more preferably 0.16 to 0.5 g / cm ³ , and 0.18 to 0.45 g / cm ³ . Is more preferable.

The thickness of the second fiber layer, the third fiber layer and the fourth fiber layer is preferably 0.1 to 1.2 mm, more preferably 0.2 to 1.0 mm, and 0.25 to 0. It is even more preferably 8.8 mm, and even more preferably 0.3 to 0.6 mm. When the thickness of these fiber layers is 0.1 mm or more, the filtration performance can be further improved. Further, when the thickness of these fiber layers is 1.2 mm or less, the fiber aggregates constituting each fiber layer do not become excessively thick, so that the filtration life does not decrease.

The thickness of the first fiber layer is set to all the fiber layers constituting the filter material of the cartridge filter from the viewpoint of appropriately adjusting the flow velocity of the object to be filtered during filtration and effectively improving the efficiency of capturing foreign substances. The smallest of the above is preferable. Further, it is preferable that the thickness of the second fiber layer is the largest among all the fiber layers constituting the filter material of the pleated filter.

The first fiber layer preferably has a tensile strength of 20 to 100 N / 5 cm, more preferably 25 to 95 N / 5 cm, and more preferably 30 to 90 N in the longitudinal direction (also referred to as MD direction or mechanical direction). It is even more preferably / 5 cm, and even more preferably 40-80 N / 5 cm. Further, in the lateral direction (also referred to as CD direction and width direction), the tensile strength is preferably 15 to 90 N / 5 cm, more preferably 15 to 80 N / 5 cm, and more preferably 25 to 75 N / 5 cm. It is even more preferable, and it is even more preferable that it is 30 to 70 N / 5 cm. When the longitudinal and lateral tensile strengths of the first fiber layer are within the above ranges, the longitudinal and lateral strengths of the first fiber layer become sufficiently high, and the first fiber layer is damaged during filtration. It becomes difficult to be done.

The second fiber layer, the third fiber layer and the fourth fiber layer preferably have a tensile strength of 5 to 100 N / 5 cm, more preferably 7 to 95 N / 5 cm, and 10 to 90 N / N in the longitudinal direction. It is even more preferably 5 cm, and even more preferably 15-80 N / 5 cm. Further, the second fiber layer, the third fiber layer and the fourth fiber layer preferably have a tensile strength of 5 to 100 N / 5 cm, more preferably 7 to 95 N / 5 cm in the lateral direction, and 10 to 10 to. It is even more preferably 90 N / 5 cm, and even more preferably 12 to 80 N / 5 cm. When the longitudinal and lateral tensile strengths of the second fiber layer, the third fiber layer and the fourth fiber layer are within the above ranges, the longitudinal and lateral strengths of these fiber aggregates are sufficiently high. , Each fiber layer is less likely to be damaged during filtration. In the present invention, the tensile strength of a fiber aggregate such as a non-woven fabric is measured based on JIS L 1096.

The first fiber layer preferably has a tensile elongation of 5 to 150%, more preferably 10 to 120%, and even more preferably 15 to 100% in the longitudinal direction. Further, the first fiber layer preferably has a tensile elongation of 5 to 200%, more preferably 7 to 100%, still more preferably 10 to 80%, and 10 to 80% in the lateral direction. Even more preferably, it is 40%. When the tensile elongation in the longitudinal direction and the lateral direction of the first fiber layer is within the above range, the first fiber layer has a certain degree of elongation, and the first fiber layer is less likely to be damaged. In the present invention, the tensile elongation of a fiber aggregate such as a non-woven fabric is measured based on JIS L 1096.

The second fiber layer, the third fiber layer and the fourth fiber layer preferably have a tensile elongation of 5 to 150%, more preferably 10 to 120%, and 15 to 100% in the longitudinal direction. It is more preferable to have. Further, the second fiber layer, the third fiber layer and the fourth fiber layer preferably have a tensile elongation of 5 to 200%, more preferably 20 to 150%, and 30 to 120 in the lateral direction. It is even more preferably%, and even more preferably 40 to 100%. When the longitudinal and lateral tensile elongations of the second fiber layer, the third fiber layer and the fourth fiber layer are within the above ranges, each fiber layer has a certain degree of elongation, and the filtrate of the filtrate has a certain degree of elongation. Since the pressure is absorbed by stretching against the pressure, each fiber layer is less likely to be damaged during use.

The air permeability of the first fiber layer is not particularly limited. From the viewpoint that the first fiber layer affects the filtration accuracy of the cartridge filter and that the fiber aggregate having a small average pore size is used as the first fiber layer, it is preferable that the air permeability of the first fiber layer is small to some extent. The air permeability of the first fiber layer is preferably in the range of 0.05 to 50 (cm ³ / cm ² / sec), and is preferably 0.1 to 20 (cm ³ / sec).
It is more preferably in the range of cm ² / sec), further preferably in the range of 0.2 to 15 (cm ³ / cm ² / sec), and more preferably in the range of 0.3 to 5 (cm ³ / cm ² ). It is even more preferable that it is within the range of / sec). When the air permeability is within the above range, the efficiency of the first fiber layer to capture foreign matter becomes high, and the cartridge filter has high filtration accuracy.

The second fiber layer, the third fiber layer and the fourth fiber layer preferably have an air permeability in the range of 1 to 100 (cm ³ / cm ² / sec) and 5 to 50 (cm ³ / cm ² / sec). It is more preferably in the range of 10 to 30 (cm ³ / cm ² / sec), and more preferably in the range of 8 to 40 (cm ³ / cm ² / sec). It is even more preferable that it is within the range. When the air permeability is within the above range, the cartridge filter can obtain the trapping performance corresponding to the combination of the fiber layers for the trapping object. The method for measuring the air permeability of the non-woven fabric will be described later.

To the extent that the effects of the present invention are not impaired, the filter material constituting the pleated type cartridge filter of the present invention includes the first fiber layer, the second fiber layer, the third fiber layer and the fourth fiber layer, as well as other fibers. It may contain a fiber layer. As the number of fiber layers constituting the filter material increases, not only the manufacturing process of the filter material becomes complicated, but also the workability may be deteriorated when the filter material is bent into a pleated shape. The material is preferably composed of 2 to 6 fiber layers. When the number of fiber layers constituting the filter material satisfies the above range, the productivity of the filter material is high, and a cartridge filter having high filtration performance can be easily obtained. The filter material constituting the cartridge filter of the present invention is more preferably composed of 3 to 5 fiber layers, and further preferably composed of 3 or 4 fiber layers.

In the filter material constituting the pleated type cartridge filter of the present invention, the fiber layer having the smallest average pore size among the fiber layers constituting the filter material, that is, the first fiber layer is not only relatively on the inflow side but also the first fiber layer. 1 It is characterized in that a fiber layer is also provided on the downstream side of the fiber layer. In the filter material constituting the cartridge filter of the present invention, the fiber layer arranged on the inflow side of the first fiber layer is 0 to 2 layers, and the fiber layer arranged on the outflow side of the first fiber layer is 1. There are 3 layers, and the number of fiber layers arranged on the outflow side of the first fiber layer is equal to the number of fiber layers arranged on the inflow side of the first fiber layer, or the outflow side of the first fiber layer It is preferable that the number of fiber layers arranged in is larger than the number of fiber layers arranged on the inflow side of the first fiber layer. In the above-mentioned filter material, the filtration accuracy is improved by arranging more fiber layers on the outflow side of the first fiber layer. In the above-mentioned filter material, the fiber layer arranged on the inflow side of the first fiber layer is 0 to 1 layer, and the fiber layer arranged on the outflow side of the first fiber layer is 1 to 3 layers. It is more preferable that the fiber layer arranged on the inflow side of the first fiber layer is 0 to 1 layer, and the fiber layer arranged on the outflow side of the first fiber layer is 1 to 2 layers. It is more preferable that the fiber layer arranged on the inflow side of the first fiber layer is one layer, and the fiber layer arranged on the outflow side of the first fiber layer is one or two layers.

When two or more fiber layers are present on the inflow side of the first fiber layer, the fiber layer located immediately before the first fiber layer when viewed from the inflow side and in contact with the first fiber layer is the second fiber layer. Become. When three or more fiber layers are present on the outflow side of the first fiber layer, the fiber aggregates constituting the filter medium are arranged in order from the inflow side, and the fiber layer located next to the first fiber layer, in other words, For example, the fiber layer in contact with the outflow side surface of the first fiber layer becomes the third fiber layer. The fiber layer located on the outflow side of the third fiber layer and immediately after the third fiber layer, in other words, the fiber layer in contact with the outflow side surface of the third fiber layer is the fourth fiber layer. Become. In this case, the fiber layer arranged on the inflow side of the first fiber layer is two layers, and the fiber layer arranged on the outflow side of the first fiber layer is two to three layers, which is the first fiber layer. The number of fiber layers arranged on the outflow side is equal to the number of fiber layers arranged on the inflow side of the first fiber layer, or the number of fiber layers arranged on the outflow side of the first fiber layer is the first. It is preferable that the number of fiber layers is larger than the number of fiber layers arranged on the inflow side of one fiber layer.

The first net and the second net are fiber aggregates composed of fibers having a fiber length of 120 mm or more or continuous fibers such as monofilaments and multifilaments, and are regulated by the constituent fibers (hereinafter, also referred to as fibers). Air gaps are formed, and per 1 cm ² 2.
It is a net having a thickness of 120 μm or more measured under a load of 94 cN. The term "regular voids formed" as used herein means that the areas and shapes of the voids formed by the fibers are not disjointed, and the voids having substantially the same area and substantially the same shape are repeated. Point to that. The shape of the void portion of the net is not limited as long as the voids having substantially the same shape are repeated in the net. The shape may be. The net is preferably a net in which fibers are arranged in a grid pattern, and more preferably a net having a square void portion. The nets preferably used in the present invention are Conwed (registered trademark) nets that can be purchased from JX Nikko Nisseki Energy Co., Ltd., Netron (registered trademark) sheets that can be purchased from Mitsui Kagaku Sangyo Co., Ltd., and Sansho Co., Ltd. There are possible Delnet (registered trademarks) and so on.

In the first net and the second net, the material of the fiber is not particularly limited, and a net made of a material suitable for the environment in which filtration is performed can be used. For example, it is possible to use a net made of a synthetic resin such as a polyolefin resin, a polyester resin, or a polyamide resin. Among these, it is preferable to use a net made of fibers made of a polyolefin resin, and more preferably a fiber made of a single component of polypropylene, for example, a monofilament having a single component of polypropylene (PP monofilament). It is a configured net. Since polypropylene has high chemical resistance, it can be used for filtering various liquids, has a low softening point and melting point, and has excellent heat processability. Shows excellent heat sealing properties.

The wire diameter (thickness of the fiber), thickness, void area, and basis weight of the first net are not particularly limited, but the wire diameter (thickness of the fiber) is preferably 0.25 to 2 mm, preferably 0.3. It is more preferably about 2 mm, and even more preferably 0.4 to 1.5 mm. When the wire diameter is within the above range, it does not deform during use and the pleating workability is improved. The thickness is preferably 0.25 to 2 mm, more preferably 0.3 to 2 mm, and even more preferably 0.4 to 1.5 mm. When the thickness is within the above range, it does not deform during use and the pleating workability is improved. The void area is preferably 0.5 to 40 mm ² , preferably 0.5 to 25.
It is more preferably mm ² and even more preferably 1 to 20 mm ² . When the void area of the net is within the above range, pressure loss and clogging can be reduced, and pleating workability is also improved. The basis weight is preferably 10 to 200 g / m ² , more preferably 30 to 150 g / m ² , and even more preferably 50 to 100 g / m ² . When the basis weight is within the above range, the strength of the entire filter medium is increased.

The wire diameter (thickness of the fiber), thickness, void area, and basis weight of the second net are not particularly limited, but the wire diameter is preferably 0.1 to 0.6 mm, preferably 0.12 to 0.5 mm. It is more preferably 0.15 to 0.5 mm, and even more preferably 0.15 to 0.5 mm. When the wire diameter is within the above range, it does not deform during use, pressure loss can be reduced, and pleating workability is improved. The thickness is preferably 0.12 to 0.6 mm, more preferably 0.14 to 0.5 mm, and even more preferably 0.15 to 0.5 mm. When the thickness is within the above range, it does not deform during use, pressure loss can be reduced, and pleating workability is improved. The void area is preferably 1 to 170 mm ² , more preferably 1 to 150 mm ² , and even more preferably 2 to 100 mm ² . When the void area of the net is within the above range, pressure loss and clogging can be reduced, and the strength of the entire filter medium can be maintained. The basis weight is preferably 10 to 200 g / m ² , more preferably 20 to 150 g / m ² , and even more preferably 30 to 100 g / m ² . When the basis weight is within the above range, the second net supports each fiber layer, and the strength of the entire filter medium is increased.

A cartridge filter can be obtained by folding the above-mentioned filter material into a pleated shape, heat-sealing both ends of the filter material, and applying end caps to both ends of the filter material. After folding the filter material into pleats and putting it in a protector (case), end caps may be attached to both ends and both ends of the filter material may be heat-sealed. For example, the filter material is pleated so that it can be folded into folds, both ends of the filter material are heat-sealed and bonded, and the filter material is stored in various plastic protectors and end caps are attached to both ends to obtain a cartridge filter. Can be done. The shape of the cartridge filter of the present invention is not particularly limited, and any shape such as a cylindrical shape, a triangular shape, a quadrangular shape, a hexagonal shape, or the like can be used, but the cartridge filter must be a cylindrical shape. Is preferable.

From the viewpoint of improving the filtration life of the cartridge filter, it is preferable that the number of pleated ridges of the pleated filter material is 8 or more per 50 mm in length of the outer peripheral portion of the filter material. The length of the outer peripheral portion of the filter material referred to here is the outer peripheral length of the outer peripheral portion of the filter material in the shape in which the pleated filter material is housed in the cross section obtained by cutting the cartridge filter. In the above cartridge filter, the number of pleated folds of the pleated filter material is more preferably 8 to 40 per 50 mm length of the outer peripheral portion of the filter material, and the number of ridges of the outer peripheral portion of the filter material is more preferably 8 to 40. It is more preferable that the number of ridges per 50 mm in length is 12 to 35. The method for measuring the filtration life will be described later.

The cartridge filter has high filtration accuracy, and the collection rate of particles having a particle diameter of 1 μm is preferably 99% or more, and more preferably 99.5% or more. The method for measuring the filtration accuracy will be described later.

Hereinafter, the present invention will be described with reference to examples. The present invention is not limited to the following examples.

The method for measuring the physical properties of the used non-woven fabric and net, and the method for measuring the physical properties and filtration performance of the cartridge filter are shown below.

(Metsuke)
A square (area 0.04 m ² ) sample with a side of 20 cm was cut out from the non-woven fabric or net, the mass (g) of the sample was measured, and the grain (g / m ² ) was calculated.

(Thickness)
The measurement was performed using a thickness measuring machine (trade name "THICKNESS GAUGE model CR-60A", manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) with a load of 2.94 cN per 1 cm ² of the sample.

(Minimum pore diameter, average pore diameter, maximum pore diameter and maximum pore diameter)
The measurement was carried out according to ASTM F 316-86 (bubble point method) using a "palm poromometer" manufactured by Porous Materials.

(Tensile strength and tensile elongation)
According to JIS L 1096 6.12.1 A method (strip method), a constant speed tension type tensile tester is used to pull the sample piece under the conditions of width 5 cm, grip interval 10 cm, and tensile speed 30 ± 2 cm / min. A test was conducted, and the load value (tensile strength) and tensile elongation at the time of cutting were measured. The tensile test was carried out with the longitudinal direction (MD direction) and the transverse direction (CD direction) of the nonwoven fabric as the tensile directions, respectively. The evaluation results are all shown by averaging the values measured for the three samples.

(Minimum fiber diameter, average fiber diameter and maximum fiber diameter)
From the scanning electron micrograph of the non-woven fabric, select any 100 fibers, measure the fiber diameters of those fibers, and set the minimum, average, and maximum values to the minimum fiber diameter, average fiber diameter, and maximum fiber, respectively. The diameter was set.

(Draftness)
The measurement was performed according to JIS L 1096 using a Frazier type tester.

(Water flow pressure loss)
The pressure difference between the inlet of the cartridge filter and the outlet of the cartridge filter when tap water was passed from the outside of the cartridge filter toward the hollow portion at a flow rate of 30 liters / minute was measured.

(Filtration accuracy)
Test water suspension conforming to JIS Z 8901 (mixture of JIS 11 type [medium diameter 2 μm] and JIS 8 type [medium diameter 6.6 to 8.6 μm] in a mass ratio of 1: 1) (Concentration: 50 ppm) was flowed from the outside of the cartridge filter toward the hollow portion at a flow rate of 20 liters / minute with uniform stirring, and 100 liters of the filtrate was collected and evaluated. In the evaluation method, the number of dust particles (M) contained in 100 liters of the test suspension before filtration and the number (N) of dust remaining in 100 liters of the filtrate after filtration are determined. Measurement was performed using a particle size distribution measuring device (manufactured by Beckman Coulter, trade name "Coulter Counter Multisizer 2"), and the collection rate for each particle size was calculated based on the formula shown below. Then, the collection rate of the particles having a particle size of 1 μm and the particle size of the particles having a collection rate of 90% were defined as filtration accuracy A and filtration accuracy B, respectively.
Collection rate (%) = {(MN) / M} x 100

(Filtration life)
Test water suspension conforming to JIS Z 8901 (mixture of JIS 11 type [medium diameter 2 μm] and JIS 8 type [medium diameter 6.6 to 8.6 μm] in a mass ratio of 1: 1) (Concentration: 50 ppm) is continuously flowed from the outside of the cartridge filter toward the hollow portion at a flow rate of 20 liters / minute while uniformly stirring, and the pressure difference (pressure loss) between the inflow side and the outflow side of the cartridge filter is 0. It was allowed to flow until it reached 2 MPa, and the total liquid flow rate at the time when the pressure difference reached 0.2 MPa was determined and used as the filtration life.

In the examples and comparative examples, the non-woven fabric shown in Table 1 below and the net shown in Table 2 were used. In Tables 1 and 2, the physical characteristics of the nonwoven fabric and the net were measured and evaluated as described above. In Table 1, "***" means unmeasured.

The non-woven fabrics 2 to 6 are melt blown non-woven fabrics, and the non-woven fabric 1 is a non-woven fabric in which the non-woven fabric 2 is calendar-processed under the following conditions and both surfaces are smoothed. The non-woven fabric 7 is a melt blown non-woven fabric A made of polypropylene fiber (weight 55 g / m ² , thickness 0.76 mm, air permeability 19.
9 cm ³ / cm ² / sec, average hole diameter 16.1 μm, maximum hole diameter 26.0 μm) was calendar-processed under the following conditions. The non-woven fabric 8 is a melt blown non-woven fabric B made of polypropylene fiber (grain 70 g / m ² , thickness 0.82 mm, air permeability 30.5 cm ³ / cm ² / sec, average pore diameter 22.2 μm, maximum pore diameter 41.1 μm) as follows. It is a calendar processed under the conditions.

<Calendar processing>
For each of the non-woven fabric 2, the melt-blown non-woven fabric A and the melt-blown non-woven fabric B, calendar processing is performed on both surfaces of the non-woven fabric with a metal heat roll under the conditions of a heating temperature of 70 ° C. and a linear pressure of 3 to 5 MPa / cm. 7 and non-woven fabric 8 were obtained.

( Reference example 1)
Non-woven fabric 6, non-woven fabric 1, non-woven fabric 2, non-woven fabric 3 and net 1 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order, and have a pleated shape. It was processed into a filter material having four fiber layers. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

(Example 2)
A pleated state in which the net 1, the non-woven fabric 1, the non-woven fabric 2, the non-woven fabric 3 and the net 2 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order. It was processed into a filter material having three fiber layers. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

( Reference example 2 )
Non-woven fabric 6, non-woven fabric 1, non-woven fabric 4, non-woven fabric 5 and net 1 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow part) of the object to be filtered in this order, and have a pleated shape. It was processed into a filter material having four fiber layers. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

(Example 4)
A pleated state in which the net 1, the non-woven fabric 1, the non-woven fabric 4, the non-woven fabric 5, and the net 2 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order. It was processed into a filter material having three fiber layers. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

( Reference example 3 )
Non-woven fabric 6, non-woven fabric 7, non-woven fabric 2, non-woven fabric 3 and net 1 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order, and have a pleated shape. It was processed into a filter material having four fiber layers. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

( Reference example 4 )
Non-woven fabric 6, non-woven fabric 8, non-woven fabric 2, non-woven fabric 3 and net 1 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order, and have a pleated shape. It was processed into a filter material having four fiber layers. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

(Comparative Example 1)
The net 1, the non-woven fabric 1, and the net 1 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order, and processed into a pleated shape to form one layer. It was used as a filter material having a fiber layer of. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

(Comparative Example 2)
A pleated state in which the net 1, the non-woven fabric 3, the non-woven fabric 2, the non-woven fabric 1 and the net 2 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order. 3 layers of fiber layers (three fiber layers made of meltblown non-woven fabric are provided, and each fiber layer is arranged so that the average pore size gradually decreases, and the outflow side of the fiber layer having the smallest average pore size There is no fiber layer in the filter material.) Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

(Comparative Example 3)
The net 1, the non-woven fabric 7, and the net 1 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order, and processed into a pleated shape to form one layer. It was used as a filter material having a fiber layer of. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

(Comparative Example 4)
The net 1, the non-woven fabric 8, and the net 1 are laminated and stacked so as to be arranged from the inflow side (outside) to the outflow side (hollow portion) of the object to be filtered in this order, and processed into a pleated shape to form one layer. It was used as a filter material having a fiber layer of. Then, both ends were heat-sealed at once, stored in a protector, and an end cap was adhered to the end face to obtain a cartridge filter.

The measurement results of the filtration performance of the cartridge filters obtained in Reference Examples 1 to 4, Examples 2 and 4, and Comparative Examples 1 to 4 are shown in Tables 3 and 4 below.

As can be seen from Table 3, the cartridge filters of Reference Examples 1 and 2 and Examples 2 and 4 have a collection rate of particles having a particle size of 1 μm of 99% or more and a collection rate of particles having a particle size of 1 μm. The filtration accuracy indicated by was extremely high. Further, the particle size of the particles having a collection rate of 90% was less than 0.7 μm, and the filtration accuracy indicated by the particle size of the particles having a collection rate of 90% was also good. On the other hand, in the cartridge filters of Comparative Examples 1 and 2, the collection rate of particles having a particle size of 1 μm is less than 75%, the particle size of particles having a collection rate of 90% is 1.50 μm or more, and filtration is performed. The accuracy was low.

Comparing Reference Examples 3 and 4 with Comparative Examples 3 and 4 in the data of Table 4, it can be seen that the effect of the cartridge filter of the present invention is exhibited even when the filtration accuracy is set to a medium level. That is, Comparative Example 3 in which only the calendered melt blown non-woven fabric is used as the fiber layer and the fiber layer used in Comparative Example 3 are used, and the fiber layer having an average pore diameter larger than the fiber layer is arranged on the downstream side. In Reference Example 3 , it can be confirmed that various filtration accuracy is improved. Similar results can be confirmed by comparing Comparative Example 4 and Reference Example 4 . From these results, even in a cartridge filter that captures particles with medium filtration accuracy, specifically particles of about 1 to 5 μm, a fiber layer whose average pore size range is adjusted is provided on the downstream side of the fiber layer having the smallest average pore size. By arranging it, it becomes possible to capture small particles with a reduced flow velocity, and the filtration accuracy is improved.

The cartridge filter of the present invention can be suitably used for filtering liquids such as beverages, chemicals, oils and fats, paints, and industrial cleaning water such as cleaning water for electronic parts and semiconductor products.

Claims (5)

A cartridge filter with a pleated filter medium
The filter medium has a first fiber layer and has a first fiber layer.
The first net is arranged on the inflow side of the first fiber layer.
The third fiber layer is arranged on the outflow side of the first fiber layer, and the third fiber layer is arranged.
The average pore size of the first fiber layer is 0.5 to 20 μm, and the average pore size is 0.5 to 20 μm.
The average pore size of the third fiber layer is 3 to 25 μm, and the average pore size is 3 to 25 μm.
The average pore size of the third fiber layer is 1.1 to 8 times the average pore size of the first fiber layer.
The total number of fiber layers constituting the filter material is 2 to 4 layers.
No fiber layer is arranged on the inflow side of the first fiber layer,
The fiber layers arranged on the outflow side of the first fiber layer are 1 to 3 layers.
A cartridge filter in which the fiber layer having the smallest average pore diameter is the first fiber layer in all the fiber layers constituting the filter material. A fourth fiber layer is further arranged on the outflow side of the third fiber layer.
The average pore size of the fourth fiber layer is 5 to 60 μm, and the average pore size is 5 to 60 μm.
The cartridge filter according to claim 1, wherein the average pore diameter of the fourth fiber layer is 1.05 to 4 times the average pore diameter of the third fiber layer. The cartridge filter according to claim 1 or 2, wherein the filter material has a second net, and the second net is arranged on the most outflow side among the fiber aggregates constituting the filter material. A cartridge filter with a pleated filter medium
The filter medium has a first fiber layer and has a first fiber layer.
A second fiber layer or a laminate of the first net and the second fiber layer is arranged on the inflow side of the first fiber layer, and the first net and the second fiber layer are arranged on the inflow side of the first fiber layer. When the laminate is arranged, the first net and the second fiber layer are arranged in this order from the inflow side.
The third fiber layer is arranged on the outflow side of the first fiber layer, and the third fiber layer is arranged.
The average pore size of the first fiber layer is 0.5 to 20 μm, and the average pore size is 0.5 to 20 μm.
The average pore size of the second fiber layer is 5 to 60 μm, and the average pore size is 5 to 60 μm.
The average pore size of the third fiber layer is 3 to 25 μm, and the average pore size is 3 to 25 μm.
The average pore size of the second fiber layer is 3 to 10 times the average pore size of the first fiber layer.
The average pore size of the third fiber layer is 1.1 to 8 times the average pore size of the first fiber layer.
The average pore size of the second fiber layer is 1.05 to 4 times the average pore size of the third fiber layer.
The total number of fiber layers constituting the filter material is three.
The second fiber layer is the only fiber layer arranged on the inflow side of the first fiber layer.
The third fiber layer is the only fiber layer arranged on the outflow side of the first fiber layer.
A cartridge filter in which the fiber layer having the smallest average pore diameter is the first fiber layer in all the fiber layers constituting the filter material. The cartridge filter according to claim 4 , wherein the filter material has a second net, and the second net is arranged on the most outflow side among the fiber aggregates constituting the filter material.