JP3436178B2 - Filter cartridge - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter cartridge useful for liquid filtration, and more particularly to a filter cartridge having high accuracy and long filtration life in which filtrate dropouts and other foreign substances are not mixed in the filtrate.

[0002]

2. Description of the Related Art At present, various filters have been developed and produced in order to purify fluids. Among them, a cartridge type filter (hereinafter referred to as a filter cartridge) whose filter material can be easily replaced is used for industrial purposes such as removal of suspended particles in industrial liquid raw materials, removal of cake flowing out from a cake filtration device, and purification of industrial water. Used in a wide range of fields above.

Several types of filter cartridge structures have been conventionally proposed. The most typical of these is a wound filter cartridge. This is a cylindrical filter cartridge that is made by winding a spun yarn that is a filter material around a perforated cylindrical core in a twill shape, and then fluffing the spun yarn.Since it is easy and inexpensive to manufacture, it has been used for a long time. ing. Another structure is a non-woven laminated filter cartridge. This is a cylindrical filter cartridge made by winding several kinds of non-woven fabric such as carding non-woven fabric around a perforated cylindrical core in a stepwise concentric manner.Several types have been put into practical use due to the recent development of non-woven fabric manufacturing technology. Has been done.

However, these filter cartridges also have some drawbacks. For example, a method for collecting foreign matter in a wound-type filter cartridge is to collect foreign matter with fluff generated from spun yarn, and to entrap the foreign matter in the gap between the spun yarns. Since it is difficult to adjust the shape, there is a drawback that the size and amount of foreign matter that can be collected are limited. Further, since the spun yarn is made of short fibers, there is a drawback that the constituent fibers of the spun yarn fall off when a fluid flows through the filter cartridge. Furthermore, when producing spun yarn, a small amount of a surfactant is often applied to the surface of the spinning machine to prevent it from adhering to the spinning machine due to static electricity or the like. When a liquid is filtered with a filter cartridge made of spun yarn coated with such a surfactant, foaming of the liquid, TOC (total organic carbon content), COD (chemical oxygen demand), and increase in electrical conductivity It may adversely affect the cleanliness of the liquid. Further, since spun yarn is produced by spinning short fibers as described above, at least two steps of spinning and spinning short fibers are required, resulting in an increase in cost.

Further, as shown in FIG. 2, the performance of a filter cartridge having a structure in which a wide non-woven fabric is wound around a perforated tubular body as it is, that is, a non-woven laminate type filter cartridge, is determined by the non-woven fabric. . Non-woven fabrics are produced by intertwining short fibers with a card machine or air-laid machine, and then heat-treating them with a hot air heater or heating rolls if necessary, or directly into non-woven fabrics by the melt blow method, spun bond method, etc. It is often done by the method. However, card machines, air-laid machines, hot air heaters, heating rolls, melt blow machines, spunbond machines, and other machines used for manufacturing nonwoven fabrics often have unevenness in the physical properties of the nonwoven fabric such as the basis weight in the machine width direction. Therefore, the quality of the filter cartridge may become poor, or the manufacturing cost may be increased by using a high-level manufacturing technique for eliminating unevenness. In addition, the nonwoven fabric laminated filter cartridge has 2 to 2
Since it is necessary to use about 6 kinds of non-woven fabrics, and further different non-woven fabrics need to be used depending on the type of the filter cartridge, the manufacturing cost may increase. Further, in the case of a nonwoven fabric laminated filter cartridge, there is also a problem that the surface is easily clogged when the performance of the nonwoven fabric used does not match the characteristics of the particles in the liquid before filtration.

Several methods have been proposed to solve the problems of the conventional filter cartridge. For example, in Japanese Utility Model Publication No. 6-7767, a filter material having a diameter of about 3 mm is squeezed by squeezing and squeezing a tape-shaped paper having porosity while twisting it around a porous inner cylinder. A filter cartridge having a different shape has been proposed. This method has a feature that the winding pitch of the winding can be increased as it goes outward from the porous inner cylinder. However, since it is necessary to squeeze the filter material to narrow it down, and because the collection of foreign matter is mainly performed between the winding pitches of the filter material, the thread-wound filter using conventional spun yarn collects foreign matter with its fluff. It is difficult to expect foreign substances to be collected by the filtration material itself. As a result, the filter may be clogged on the surface to shorten the filtration life, or the liquid permeability may be poor.

As another method, Japanese Patent Laid-Open No. 1-115423
Japanese Patent Publication proposes a filter in which a cellulose-spunbonded non-woven fabric is cut into strips and wound with a string that is twisted through narrow holes on a bobbin with multiple fine holes. Has been done. If this method is used, a mechanical strength is higher than that of a roll tissue filter in which conventional α-cellulose obtained by refining softwood pulp is wound into a roll, and it has high mechanical strength, and it does not dissolve in water or elute the binder. It is thought that it can be done. However, the cellulose-spunbond nonwoven fabric used for this filter is too rigid because it is in the form of paper, and it is a filtering material that the conventional bobbin-shaped filter collects foreign substances with its fluff. It is difficult to expect foreign material collection by itself. In addition, since the cellulose-spunbond nonwoven fabric has a paper-like form, it easily swells in liquid, which causes various problems such as decrease in filter strength, change in filtration accuracy, deterioration of liquid permeability, and decrease in filtration life. May occur. In addition, the adhesion of the fiber intersections of the cellulose-spunbond nonwoven fabric is often performed by chemical treatment, etc., but the adhesion is often insufficient, which may cause a change in filtration accuracy or cause a fiber scrap. It is difficult to obtain stable filtration performance because it often becomes the cause of dropout.

Further, in Japanese Patent Laid-Open No. 4-45810,
A filter in which a slit nonwoven fabric composed of composite fibers in which 10% by weight or more of the constituent fibers is divided into 0.5 denier or less is wound around a porous core cylinder so that the fiber density is 0.18 to 0.30. Proposed. The use of this method has a feature that fine particles in a liquid can be captured by fibers having a small fineness. However, it is necessary to use physical stress such as high-pressure water to divide the composite fiber, and it is difficult to uniformly divide the whole nonwoven fabric by high-pressure water processing. If the particles are not uniformly divided, a difference may occur in the trapped particle size between a well-divided portion and a poorly-divided portion in the non-woven fabric, which may result in coarse filtration accuracy. In addition, the strength of the non-woven fabric may decrease due to the physical stress used when dividing, so that the strength of the manufactured filter decreases and it becomes easy to deform during use, or the porosity of the filter changes, and Liquidity may decrease. Furthermore, if the strength of the nonwoven fabric is low, it becomes difficult to adjust the tension when winding on the porous core cylinder, and thus it may be difficult to finely adjust the porosity. Furthermore, the manufacturing cost of the filter will increase due to the increase in the spinning technology required for making easily split fibers and the increase in the operating cost during manufacturing. It is considered that it can be used in some fields such as industry where high filtration performance is required,
It seems to be difficult to use in applications where the filter is required to be inexpensive, such as filtration of pool water and filtration of plating solution for plating industry.

On the other hand, apart from these measures, there is an attempt to improve the performance of the filter by making the filter medium into a multilayer structure. For example, Japanese Utility Model Publication No. 4-131412, Japanese Utility Model Publication No. 4
-131413 and Japanese Utility Model Laid-Open No. 5-2715,
A method of making a cylindrical cartridge filter composed of several layers by using a nonwoven fabric containing ultrafine fibers obtained by dividing a splittable conjugate fiber is disclosed. The layer structure is composed of a nonwoven fabric winding layer containing ultrafine fibers and a spun yarn layer (Japanese Utility Model Laid-Open No. 4-131414), and a slit nonwoven fabric winding layer containing ultrafine fibers, a slit nonwoven fabric and a yarn were wound together. Which is composed of a layer and a spun yarn winding layer (Japanese Utility Model Publication No. 4-131413), a slit nonwoven fabric winding layer containing ultrafine fibers and a slit nonwoven fabric winding layer having a fiber diameter at least twice that of the layer (Shinkaihei 5-5-).
2715). Since each of these filters has a multilayer structure, it is expected that the filtration life will be longer than that of a filter having a single layer structure, but the problem due to the use of the split fiber as described above is solved. It has not been.

Further, Japanese Utility Model Publication No. 4-30007 discloses that
A filter element having a two-layer structure is disclosed, which includes a core having a large number of through holes, a pleat filter in which a plurality of surface filter media on the outer periphery of the core are folded to make an endless shape, and a wound filter on the outer periphery of the core. However, since spun yarn is used for this filter element, the problems caused by using spun yarn as described above have not been solved.

Several other methods are known for filters having a multi-layer structure, but most of them have focused on the most precise layer among the layers. In other words, for high-precision layers, we are making various advanced efforts, but for other layers, we are only paying attention to the magnitude of filtration accuracy, and we have not made such ingenuity. Many. For example, when spun yarn is used in a layer other than the high-precision layer, the problems such as the loss of constituent fibers of the spun yarn and the bubbling from the filter medium as described above have not been solved yet, so a multilayer structure is used. May result in poorer performance or may have limited applications than filters made from only high precision layers. Even when a material other than spun yarn is used, when the conventional filter medium is used for a layer other than the high-precision layer, the problems of the conventional filter medium are directly taken over or become very expensive. . Further, in the filters having a multi-layered structure produced by these methods, further improvement in basic characteristics of the filter such as filter life and water permeability has been demanded.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a filter cartridge which is highly accurate, has a long filtration life, and does not contain a filter material dropout or other foreign matter in the filtrate.

As a result of intensive research and development by the present inventors in order to solve the above-mentioned problems, a belt-shaped long-fiber non-woven fabric made of a thermoplastic fiber and having at least a part of its fiber intersections bonded is formed into a cylindrical twill shape. By providing a filter cartridge composed of the wound first filtration layer and the second filtration layer having a higher accuracy than the first filtration layer located on the downstream side (the side closer to the filtrate) than the first filtration layer, The inventors have found that it is possible to obtain a cylindrical filter cartridge having excellent liquidity, filtration life, stability of filtration accuracy, etc., and have reached the present invention.

[0014]

The present invention has the following constitution. (1) A first filtration layer formed by winding a belt-shaped long-fiber non-woven fabric, which is made of a thermoplastic fiber and has at least a part of its fiber intersections bonded, in a twill shape in a cylindrical shape; 0.05-0.9 of the initial 80% trapped particle size of one filtration layer
A filter cartridge consisting of a double filtration layer. (2) The filter cartridge according to item (1), wherein the thermoplastic fiber is a thermoadhesive composite fiber composed of a low melting point resin and a high melting point resin, and a melting point difference between the two resins is 10 ° C. or more. (3) The low melting point resin is linear low density polyethylene,
The filter cartridge according to item (2), wherein the high melting point resin is polypropylene. (4) The belt-shaped long-fiber nonwoven fabric is bonded at its fiber intersections by thermocompression bonding with a hot embossing roll (1) to
The filter cartridge according to any one of items (3). (5) The filter cartridge according to any one of items (1) to (3), wherein the fiber-shaped intersections of the strip-shaped long-fiber nonwoven fabric are bonded by hot air. (6) Twist is added to the belt-shaped long-fiber nonwoven fabric (1) to
The filter cartridge according to any one of items (5). (7) A belt-shaped long-fiber non-woven fabric is used for the cross section of the pleated material with 4 to 5
The filter cartridge according to any one of items (1) to (5), which is a pleated material having 0 pleats and is wound in a twill shape on a perforated tubular body. (8) The filter cartridge according to item (7), wherein at least a part of the pleats of the pleats are non-parallel. (9) The filter cartridge according to item (7), wherein the porosity of the pleats is 60 to 95%. (10) The filter cartridge according to any one of (1) to (9), wherein the first filtration layer of the filter cartridge has a porosity of 65 to 85%. (11) The belt-shaped long-fiber nonwoven fabric is obtained by slitting a wide-width long-fiber nonwoven fabric and has a width of 0.5 cm or more. The product of basis weight (g / m ² ) is 200 or less (1) to
The filter cartridge according to any one of items (10). (12) The filter cartridge according to item (1), wherein the second filtration layer is formed by winding a perforated sheet around a perforated tubular body in a stencil shape. (13) A filtration layer obtained by winding a strip-shaped long-fiber nonwoven fabric in which a second filtration layer is made of a thermoplastic fiber around a perforated tubular body and at least a part of its fiber intersections are bonded in a cylindrical twill shape. And a b filter layer in which a band-shaped long-fiber nonwoven fabric is wound in a cylindrical twill shape continuously from a filter layer while winding a perforated sheet in a roll shape, and the first filter layer is The filter cartridge according to item (1), which is a filtration layer formed by continuously winding a strip-shaped long-fiber nonwoven fabric in a cylindrical shape in a twill shape from the second filtration layer. (14) The filter cartridge according to item (1), wherein the second filtration layer is formed by bending a perforated sheet around the perforated tubular body in a pleat shape into a tubular shape. (15) A tubular molded body in which the second filtration layer is composed of thermoadhesive conjugate fibers made of two kinds of thermoplastic resins having a melting point difference of 10 ° C. or more, and the intersections of the thermoadhesive conjugate fibers are adhered (1 )
The filter cartridge according to item.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Aspects of the present invention will be specifically described below.

In the filter cartridge of the present invention, a belt-shaped long fiber non-woven fabric (hereinafter, referred to as a band-shaped long fiber non-woven fabric) made of a thermoplastic fiber and having at least a part of its fiber intersections adhered is wound in a cylindrical shape in a twill shape. And a second filtration layer having an initial 80% trapped particle size of 0.05 to 0.9 times the initial 80% trapped particle size of the first filter layer. The second filtration layer is located on the downstream side (closer to the filtrate) than the first filtration layer. FIG. 1 is an example of a case where a fluid flows from the outer side to the inner side of a cylinder, and the first filtration layer 1 is located on the outer peripheral side of the second filtration layer 2. When the pressure resistance of the second filtration layer is weak, a perforated core may be provided to maintain the strength, and a three-layer structure or more in which a third filtration layer is provided within a range that does not impair the effects of the present invention. Of course, it does not matter even if it has a multi-layer structure. When using a structure with three or more layers,
A layer for the purpose other than particle trapping, such as an activated carbon layer, may be provided, or the initial 80% trapped particle diameter of the third filter layer may be set to 0.05 to the initial 80% trapped particle diameter of the second filter layer. The filtration life may be further extended by increasing it to 0.9 times.

First, the initial 80% trapped particle size will be described. What is the initial 80% collection particle size of a certain filter?
The particle size is such that the particle collection efficiency at that particle size is exactly 80%. There are various methods to obtain it.
The method of TM F795-88 is reliable. The outline is that the filter is attached to the circulation type filtration performance tester,
After circulating water with a pump, pass a liquid (pre-filtration liquid) in which a cake such as AC Fine Test Dust is turbid through the filter to obtain a filtration liquid, and dilute the pre-filtration liquid and the filtration liquid at appropriate ratios, respectively. The number of particles contained in the liquid is measured with a light-blocking particle detector to calculate the initial collection efficiency at each particle size. In this specification, the particle size at which the collection efficiency shows 80% by interpolating the value is defined as the initial 80% collection particle size. In many cases, the initial collection efficiency monotonically increases with respect to the particle size, and in that case, the initial 80% collection particle size is uniquely obtained for each filter. In rare cases, the initial collection efficiency curve does not increase monotonically, and there may be two or more particle sizes at which the particle collection efficiency is exactly 80%.
In that case, the smallest particle size among them is defined as the 80% collected particle size of the filter.

Since the filter cartridge of the present invention has a structure composed of the first filtration layer and the second filtration layer, the initial 80% trapped particle size of each layer is measured as it is while maintaining the shape of the filter cartridge. Is difficult to do. Therefore, the following two methods are used.

The first method is a method of separately manufacturing the first filtration layer and the second filtration layer. This method can be used when the manufacturing conditions of each layer are known. When the shape cannot be maintained only by each layer, it is preferable to use an appropriate dummy, for example, a perforated plastic molded product having a hollow inside.

The second method is a method of analyzing and obtaining measurement data. This method may be used when the manufacturing conditions of each layer are unknown. First, the collection efficiency of the filter cartridge for each particle size is measured. Next, the first filtration layer is removed from the filter cartridge, leaving only the second filtration layer. The relationship between the collection efficiencies of the first filtration layer, the second filtration layer, and the filter cartridge follows the following formula.

(1-collection efficiency of filter cartridge) = (1-collection efficiency of first filtration layer) × (1-collection efficiency of second filtration layer)

Therefore, if the collection efficiency of the filter cartridge and the second filtration layer is obtained, the collection efficiency of the first filtration layer can be analytically obtained. It will be apparent that this method can be applied even when the number of layers is three or more. With this method, the collection efficiency at each particle size of each layer was calculated, and the value was interpolated to obtain an initial value of 80.
The% trapped particle size may be calculated. Further, if it is difficult to remove the first filtration layer, it can be similarly obtained by removing the second filtration layer and measuring.

Any thermoplastic resin capable of melt spinning can be used for the thermoplastic fibers constituting the strip-shaped long-fiber nonwoven fabric used in the present invention. Examples thereof include polypropylene, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, and co-polymerized polypropylene (for example, propylene as a main component, ethylene, butene-1,4-methylpentene-1, etc. Copolymers) and other polyolefin resins, polyethylene terephthalate, polybutylene terephthalate, polyester resins such as these low melting point polyesters copolymerized by adding isophthalic acid in addition to terephthalic acid as an acid component, nylon 6, polyamide resin such as nylon 66, polystyrene resin (atactic polystyrene, syndiotactic polystyrene),
Thermoplastic resins such as polyurethane elastomers, polyester elastomers and polytetrafluoroethylene can be presented. Further, a functional resin such as a biodegradable resin such as lactic acid type polyester may be used to impart biodegradability to the filter cartridge. In addition, when using a resin that can be polymerized with a metallocene catalyst such as a polyolefin resin or polystyrene, if you use a resin polymerized with a metallocene catalyst, the strength of the nonwoven fabric is improved, the chemical resistance is improved, and the production energy is reduced. Are preferred for use in the filter cartridge. Further, these resins may be blended and used in order to adjust the thermal adhesiveness and the rigidity of the long fiber nonwoven fabric. Of these, polyolefin resins such as polypropylene are preferable from the viewpoint of chemical resistance and price when the filter cartridge is used for filtering an aqueous liquid at room temperature, and when used for a liquid having a relatively high temperature, Polyester resins, polyamide resins, syndiotactic polystyrene resins, etc. are preferred.

The thermoplastic fiber used in the present invention is
It is preferable that the thermoadhesive conjugate fiber is composed of a low melting point resin and a high melting point resin having a melting point difference of 10 ° C. or higher, preferably 15 ° C. or higher. By using the heat-adhesive composite fiber, only a part of the single fiber is melted at the time of heat-adhesion so that the shape of the adhesion point is smooth and the heat-bonding of the fiber-bonding point of the non-woven fabric is stable. When used for, the possibility that particles captured near the fiber junction will flow out when the filtration pressure or water flow rate is increased, the deformation of the filter cartridge will be reduced, and further it will be contained in the filtrate. Even if the fiber deteriorates due to the substance, the probability that the fiber will fall off will be small, and the risk of the resin being mixed into the filtrate due to the collapse of the bonding point becomes smaller. There is no particular upper limit of the melting point difference, but among the thermoplastic resins capable of melt spinning, the temperature difference between the highest melting point resin and the lowest melting point resin is applicable. In the case of a resin having no melting point, the flow starting temperature is regarded as the melting point.

In the combination of the low melting point resin and the high melting point resin of the above-mentioned heat-bondable composite fiber, the melting point difference is 10 ° C. or more, preferably
It is not particularly limited as long as it is 5 ° C. or more, and linear low-density polyethylene / polypropylene, high-density polyethylene / polypropylene, low-density polyethylene / polypropylene, copolymers of propylene and other α-olefin / polypropylene, linear Low density polyethylene / high density polyethylene, low density polyethylene / high density polyethylene, various polyethylene / thermoplastic polyesters, polypropylene / thermoplastic polyester, copolyester / thermoplastic polyester, various polyethylene / nylon 6, polypropylene / nylon 6, Nylon 6 / nylon 66, nylon 6 / thermoplastic polyester, etc. may be mentioned. Above all, it is preferable to use a combination of linear low-density polyethylene / polypropylene because the rigidity and the porosity of the long-fiber nonwoven fabric can be easily adjusted in the step of adhering the fiber intersections during the production of the nonwoven fabric. When used in a liquid of relatively high temperature, a combination of low melting point polyester / polyethylene terephthalate obtained by copolymerizing an acid component with isophthalic acid in addition to terephthalic acid can also be preferably used.

The long fiber non-woven fabric used in the present invention as the strip long fiber non-woven fabric is a long fiber non-woven fabric obtained by a spunbond method or the like. As shown in FIG. 14, the long-fiber non-woven fabric made by the spunbond method has the fiber directions aligned in the machine direction, so that the pores formed by the fibers 23 are elongated and the maximum passing particles 24 are small. On the other hand, in the case of a non-woven fabric made of short fibers obtained by the card method or the like, the fiber direction is not constant as shown in FIG.
The pores formed by the fibers 25 have a shape close to a circle or a square, and the maximum passing particle diameter 24 is large even if the open area ratio is the same as that of the long fiber nonwoven fabric produced by the spunbond method or the like. Since the water permeability of the filter medium is almost determined by the porosity if the fiber diameter is the same, a filter excellent in water permeability can be obtained by using a long fiber non-woven fabric made by the spunbond method or the like. This effect is reduced when a binder such as an adhesive that blocks the pores of the filter medium is used, and therefore the use of a cellulose spunbonded nonwoven fabric is not preferable. Further, when the cellulose spunbonded nonwoven fabric is used, the strength of the nonwoven fabric is weakened, so that there is a problem that the pores formed by the fibers are easily deformed when the filtration pressure is increased due to clogging of the filter or the like. Also, long-fiber non-woven fabrics made of thermoplastic fibers to which at least a part of the fiber intersections are adhered include low-molecular components such as fiber surface agents (for example, surfactants) unlike many short-fiber non-woven fabrics. Since it is a long fiber, the end of the fiber is extremely small and the filter medium does not almost fall off. Therefore, if this is used as the filter medium, the possibility that the filtrate is contaminated is very low compared to other materials. .

The average single-filament fineness of the long-fiber non-woven fabric used in the present invention varies depending on the use of the filter cartridge and the type of resin, but it cannot be generally specified.
The range of 0.6 to 3000 dtex is desirable. Fineness 3
When it exceeds 000 dtex, there is no difference from the case where a continuous yarn is simply bundled, and it becomes meaningless to use a long fiber nonwoven fabric. Further, since it is possible to obtain a sufficient nonwoven fabric strength by setting it to 0.6 dtex or more, it is possible to easily process this nonwoven fabric into a pleated material by the method described later, and further, it is possible to It is preferable because it has high strength. In addition, when a fiber having a fineness of less than 0.6 dtex is to be spun by the current spunbond method, the nozzle used has poor processability and spinnability, and as a result, the cost of the spunbond nonwoven fabric produced is high. May be.

The constituent fibers of the long-fiber non-woven fabric used in the present invention do not always have to have a circular cross section, and a yarn having an irregular cross section can also be used. In that case, the larger the surface area of the filter, the larger the collection of fine particles,
It is possible to make a filter cartridge with the same liquid permeability and higher precision than when using fibers having a circular cross section.

Within the range that does not impair the effects of the present invention, the long fiber non-woven fabric is mixed with a hydrophilic resin such as polyvinyl alcohol, or the surface of the long fiber non-woven fabric is subjected to plasma processing. When the non-woven fabric is made hydrophilic, liquid permeability is improved when it is used for an aqueous liquid, and therefore, when an aqueous solution is filtered, a filter using such a resin is preferable.

The thermal bonding method of the fiber intersections of the long fiber non-woven fabric used in the present invention is a method of thermocompression bonding using a device such as a hot embossing roll or a hot flat calender roll, a hot air circulating type, a hot through air type. , Infrared heater type,
Examples include a method of using a heat treatment machine such as a vertical hot air jet type. Among them, the method of using the hot embossing roll is preferable because the production speed of the nonwoven fabric can be improved, the productivity is good, and the cost is low.

Further, as shown in FIG. 3, the long fiber non-woven fabric produced by the method of using the hot embossing roll has only the portion 5 where strong thermocompression bonding is caused by the embossing pattern and the weak thermocompression bonding due to the fact that the embossing pattern deviates. There is a part 6 with. As a result, a large amount of foreign matters 7 and 8 can be collected in the portion 5 where strong thermocompression bonding is performed.
On the other hand, in the part 6 where only weak thermocompression bonding is applied, part of the foreign matter is collected, but the remaining foreign matter passes through the long-fiber nonwoven fabric. Since it is possible to move to the next layer, a deep layer filtration structure utilizing the inside of the filter medium is preferable.

In this case, the area of the embossed pattern is 5 to
It is desirable to be 25%. By setting this area to 5% or more, it is possible to improve the effect due to the thermal bonding of the fiber intersections described above, and by setting it to 25% or less, it is possible to prevent the rigidity of the nonwoven fabric from becoming too large, Alternatively, it is possible to extend the life of the filter by facilitating the foreign matter to pass through the long-fiber nonwoven fabric to some extent and trapping the foreign matter that has passed through inside the filter.

After processing into the shape of the filter cartridge by the method described later, the fiber intersections may be heat-bonded by infrared rays or steam treatment. Alternatively, it is possible to chemically bond the fiber intersections using an adhesive such as an epoxy resin, but the porosity is lower than that in the case of thermal bonding, and therefore the liquid permeability may be reduced.

The basis weight of the long-fiber nonwoven fabric used in the present invention, that is, the weight per unit area of the nonwoven fabric is 5 to 200.
g / m ² is preferred. If this value is less than 5 g / m ² ,
Since the amount of fibers becomes small, the unevenness of the non-woven fabric may increase, the strength of the non-woven fabric may decrease, or the above-described thermal joining of the fiber intersections may become difficult. On the other hand, if this value exceeds 200 g / m ² , the rigidity of the non-woven fabric becomes too high, and it becomes difficult to wrap it around the perforated tubular body later in a twill shape.

The long-fiber non-woven fabric used in the present invention is in a band shape. In order to obtain a belt-shaped long-fiber nonwoven fabric, a method of directly adjusting the spinning width to directly make a belt-shaped nonwoven fabric can be used, but more preferably, a method of slitting a wide-fiber long-fiber nonwoven fabric into a belt-like shape is used. The main reason for forming the belt-like shape is to improve the performance of the filter itself as described later, but there are other reasons. It is wide (eg 5
This means that the unevenness of the long-fiber non-woven fabric (having a width of 00 mm or more) is substantially eliminated. As mentioned above, the spunbond method is generally used to make long-fiber non-woven fabrics, but the spunbond method is to suck and stretch the fibers discharged from a nozzle with an air sucker and hit them on a collecting conveyor. Since it is a method of dispersing, the non-woven fabric is likely to have spots. Furthermore, resin lumps generated by yarn breakage during spinning,
Non-woven fabric spots are also generated due to the basis weight of the non-woven fabric due to discharge spots or the spot size of the fiber diameter. The cause of occurrence of such non-woven fabric unevenness varies depending on the manufacturing method, but it occurs even when a manufacturing method other than the spun bond method is used. In order to eliminate such unevenness of the non-woven fabric, it is common practice to physically remove defective parts from the product or to make full use of advanced spinning technology. It will have a negative effect on sexuality.

Therefore, the present inventors have studied the characteristics of many non-woven fabrics including long-fiber non-woven fabrics, and as a result, the non-woven fabrics tend to be uneven in the machine width direction but relatively in the non-woven fabric flow direction. I found a few. The present inventors further examined the results, and when the width of the nonwoven fabric was 0.5 cm
It was noticed that when cut into strips of several centimeters, the non-woven fabric spots became negligibly small within the width of each strip. By using the method of the present invention described below, it is possible to change the filtering performance by the method of molding the filter medium, so if the molding method is adjusted for each physical property of the band-shaped nonwoven fabric, the performance irregularities of the produced filter will almost disappear. is there. This can be expected to greatly improve productivity and basic unit.

The width in the case of slitting a wide-fiber nonwoven fabric having a wide width into a strip-shaped long-fiber nonwoven fabric is preferably 0.5 cm or more, although it varies depending on the basis weight of the nonwoven fabric used. If this width is less than 0.5 cm, the nonwoven fabric may be cut during slitting, and it becomes difficult to adjust the tension when the strip-shaped nonwoven fabric is wound in a twill shape later, and a filter having the same porosity is produced. In this case, the winding time becomes long and the productivity decreases. On the other hand, the upper limit of the width depends on the basis weight,
The value of width (cm) x basis weight (g / m ² ) is preferably 200 or less. For example, when the basis weight is 20 g / m ² , the upper limit is 10 cm. When this value exceeds 200, the rigidity of the non-woven fabric becomes too high, which makes it difficult to wrap it around the perforated tubular body later in a twill shape, and further, the amount of fibers becomes too large, making it difficult to wrap it tightly. In addition,
Even when the spinning width is adjusted to directly make a non-woven fabric in a strip shape, the preferable basis weight and the range of the width of the non-woven fabric are the same as those in the case of slitting into a strip shape.

The band-shaped long-fiber nonwoven fabric may be appropriately processed by a method described below and then wound in a twill shape on the second filtration layer (details of the second filtration layer will be described later). You may wind it up as it is. An example of the manufacturing method in this case is shown in FIG. The winder used in a normal spool filter cartridge can be used in the winder.
The supplied long-fiber nonwoven fabric 9 passes through the traverse guide 10 having a narrow hole which moves while traversing, and then the bobbin 1
The filter cartridge 12 is wound up on the second filtration layer 2 attached to No. 1. Since the filter cartridge manufactured by this method is very dense, it becomes a filter cartridge with high precision. However, it is difficult to adjust the filtration accuracy by changing the manufacturing conditions by this method.

On the other hand, it is also possible to wind the strip-shaped long-fiber nonwoven fabric after twisting it. An example of the manufacturing method in this case is shown in FIG. In this case as well, the winder used in a normal spool filter cartridge can be used in the winder. Since the nonwoven fabric is apparently thick due to the twist, it is preferable that the traverse guide 13 has a larger hole diameter than that in the case of FIG. When twist is added to the nonwoven fabric, the apparent porosity of the nonwoven fabric can be changed by the number of twists per unit length or the twisting strength, so that the filtration accuracy can be adjusted. The number of twists at this time is preferably in the range of 50 to 1000 times per 1 m of the belt-shaped long fiber nonwoven fabric. If this value is less than 50 times, the effect of adding a twist is hardly obtained. Further, if this value exceeds 1000 times, the produced filter cartridge becomes rough in liquid permeability, which is not preferable.

Further, it is more preferable that the above-mentioned strip-shaped long-fiber nonwoven fabric is bundled by an appropriate method and then wound around a perforated tubular body. As the method, the belt-shaped long fiber non-woven fabric may be simply bundled through appropriate small holes or the like, or the belt-shaped long fiber non-woven fabric may be preformed to have a cross-sectional shape with an appropriate pleating guide and then pleated through the small holes or the like. You may process. By using this method, the winding pattern can be changed by adjusting the traverse speed of the traverse guide and the rotation speed of the bobbin, so it is possible to make filter cartridges of various performances from the same type of long continuous fiber non-woven fabric. .

FIG. 6 shows an example of a manufacturing method in which a proper small hole is simply passed through as a method for bundling the belt-shaped long-fiber nonwoven fabric. In this case as well, the winder used in a normal spool filter cartridge can be used in the winder.
In FIG. 6, the band-shaped long-fiber nonwoven fabric is bundled by forming the holes of the traverse guide 14 as small holes, but a small hole guide may be provided in the yarn path before the traverse guide 14. The diameter of the small holes depends on the areal weight and width of the belt-shaped long fiber nonwoven fabric used, but is preferably in the range of 3 mm to 10 mm. If this diameter is less than 3 mm, the friction between the strip-shaped long-fiber nonwoven fabric and the small holes becomes large, and the winding tension becomes too high. Further, if this value exceeds 10 mm, the bundle size of the strip-shaped long-fiber nonwoven fabric becomes unstable.

Next, FIG. 7 is a partially cutaway perspective view showing an example of a manufacturing method in the case where the band-shaped long-fiber nonwoven fabric is preformed in cross section with an appropriate pleating guide and then processed into pleats through small holes or the like. Shown in. In this case as well, the winder used in a normal spool filter cartridge can be used in the winder. When this method is adopted, the belt-shaped long fiber non-woven fabric 9 is preformed in cross section through the pleating guide 19 and then the pleats 18 through the small holes 17, and the pleats 18 are shown in FIG. In the direction of, and wound on the second filtration layer through the traverse guide to form a filter cartridge.

Next, the fold forming guide will be described. The pleat-forming guide is usually formed by processing a round bar having an outer diameter of about 3 mm to 10 mm, and then processing the surface with a fluororesin processing for preventing friction with a non-woven fabric. An example of the shape is shown in FIGS. In the example given here, the pleating guide 19 comprises an external regulation guide 15 and an internal regulation guide 16. The shape of the fold forming guide 19 is not particularly limited, but it is preferable that the fold forming guide 19 has a shape in which the folds formed from the guide are converged so that the folds are not parallel to each other. One example of the cross-sectional shape of the pleated material thus produced is shown in FIGS. 10A, 10B and 10C, but the invention is not limited to these. In these aspects of the invention, the formation of pleats that are focused such that at least some of the pleats are non-parallel are the most preferred aspects of the invention. That is, when some of the folds are not parallel as in the cross-sectional shape of FIG.
Compared to the case where most of the folds are parallel as shown in (A) and (B), the shape-holding force of the pleats is stronger even when the filtration pressure is applied to the folds from the vertical direction as shown by the arrow. It is possible to maintain the filtration function as a pleated shape. In other words, it is particularly preferable that the folds have a non-folded cross-sectional shape because the folds are non-parallel when compared with the folds that are parallel, because the ability to suppress the pressure loss of the filter cartridge is superior. . It should be noted that the number of guides does not necessarily have to be one. If several guides of different shapes and sizes are arranged in series to gradually change the cross-sectional shape of the strip-shaped long-fiber nonwoven fabric, a pleated material can be obtained. Since the cross-sectional shape of is uniform depending on the location, unevenness in quality is eliminated, which is preferable.

In the present invention, when the strip-shaped long fiber nonwoven fabric is formed into a pleated material and then wound around the second filtration layer, the final number of pleats is 4 to 50, more preferably 7 to.
It is 45. If the number of pleats is less than 4, the effect of expanding the filtration area by adding pleats is poor. On the other hand, the number of folds is 50
If the number is more than the number, the pleats become too small, which makes it difficult to manufacture, and tends to affect the deterioration of the filtration function.

In addition, for example, a comb-shaped pleating guide 20 as shown in FIG. 12 is used to impart a large number of pleats to a long-fiber nonwoven fabric, and then a narrower rectangular hole 21 is made to pass therethrough, so that the number of pleats is further increased. It can be deformed and the pleats can be at random and non-parallel.

Further, by heating the pleats 18 after passing through the small holes 17 described above with hot air or an infrared heater, the cross-sectional shape of the pleats can be fixed. This step is not always necessary, but when the pleated material has a complicated cross-sectional shape, or when a strip-shaped long-fiber nonwoven fabric having a high rigidity is used, the cross-sectional shape may collapse from the designed shape. Therefore, it is preferable to perform such heat processing.

Next, the porosity of the bundled long fiber non-woven fabric or pleated material (hereinafter collectively referred to as the band long fiber non-woven fabric bundle) used in the present invention will be described. First, the cross-sectional area of the band-shaped long-fiber nonwoven fabric bundle is shown in FIG.
As shown in, the area is defined as the area of the smallest oval 22 that encloses the band-shaped long-fiber nonwoven fabric bundle 4 (the oval means a polygon whose interior angles are all within 180 degrees). Then, the band-shaped long-fiber non-woven fabric bundle is cut into an appropriate length, for example, 100 times the square root of the cross-sectional area, and defined by the following formula.

(Apparent volume of band-shaped long fiber nonwoven fabric bundle)
= (Cross-sectional area of the band-shaped long-fiber nonwoven fabric bundle x cut length of the band-shaped long-fiber nonwoven fabric bundle)

(True volume of band-shaped long fiber nonwoven fabric bundle) =
(Weight of cut band-shaped long fiber nonwoven fabric bundle) / (Specific gravity of raw material of band-shaped long fiber nonwoven fabric bundle)

(Porosity of band-shaped long fiber nonwoven fabric bundle) =
{1- (true volume of band-shaped long fiber nonwoven fabric bundle) / (apparent volume of band-shaped long fiber nonwoven fabric bundle)} × 100%

The porosity of the band-shaped long fiber nonwoven fabric bundle defined by this formula is preferably 60 to 95%, more preferably 85 to 92%. By setting this value to 60% or more, it is possible to prevent the band-shaped long fiber non-woven fabric bundle from becoming unnecessarily dense, and to sufficiently suppress the pressure loss when used as a filter cartridge, or the band-shaped long fiber non-woven fabric bundle. It is possible to further improve the efficiency of collecting foreign matter in the object. Further, by setting this value to 95% or less, it is possible to easily wind it later, and it is possible to further reduce the deformation of the filter medium due to the load pressure when used as a filter cartridge. Examples of methods for adjusting this include adjusting winding tension and adjusting guide shapes such as pleating guides.

Further, when the band-shaped long fiber nonwoven fabric bundle is produced, granular activated carbon, ion exchange resin or the like may be mixed and processed within a range not impairing the effects of the present invention. In that case, in order to fix the granular activated carbon or the ion exchange resin, the band-shaped long-fiber nonwoven fabric may be bonded with a suitable binder before or after being processed into a bundled or pleated material, or the granular activated carbon or It is also possible to mix ion exchange resins and the like and then heat them to thermally bond the constituent fibers of the long-fiber nonwoven fabric.

Next, the band-shaped long fiber non-woven fabric bundle produced by the above-mentioned method does not necessarily need to be a continuous process if devised so that the cross-sectional shape does not collapse, and it is wound around an appropriate bobbin once. You may wind it up with a winder later.

Next, a method of winding the strip-shaped long fiber nonwoven fabric will be described. The bobbin of this winder has a diameter of about 1
A second filtration layer having a length of 0 to 40 mm and a length of 100 to 1000 mm is attached, and a belt-shaped long fiber non-woven fabric (or a band-shaped long fiber non-woven fabric bundle) passed through a yarn path of a winder is fixed to an end of a perforated tubular body. To do. Since the yarn path of the winder is traversed by the traverse cam installed parallel to the bobbin, the strip-shaped long fiber nonwoven fabric is swirled and wound around the second filtration layer. The winding condition at that time may be set in accordance with the normal winding type filter cartridge manufacturing process. For example, the bobbin initial speed is set to 1000 to 2000 rpm,
It may be wound by adjusting the feeding speed and applying an appropriate tension. The porosity of the filter cartridge can also be changed by the tension at this time. Furthermore, the tension at the time of winding can be adjusted to make the porosity of the inner layer dense, and the porosity can be made coarser as the inner layer and the outer layer are wound. In particular, in the case of winding the long strip non-woven fabric as a pleated material and then wrapping it around the second filtration layer, it is formed with the outer layer, the middle layer and the inner layer in the first filtration layer together with the deep filtration structure by the fold formation provided in the pleated material. It is possible to provide a filter cartridge having an ideal filtration structure due to the difference in coarse and fine structure.
The filtration accuracy can also be changed by adjusting the ratio between the traverse speed of the traverse cam and the rotation speed of the bobbin to change the winding pattern. The method of applying the pattern can be carried out by using a known method of a conventional wound-type filter cartridge, and when the length of the filter is constant, the pattern can be represented by the wind number. It should be noted that when the gap 26 between a certain yarn (in the case of the present invention, a strip-shaped long-fiber non-woven fabric) and the yarn wound on the layer immediately below it is wide, the filtering accuracy becomes coarse, and conversely, when it is narrow, it becomes fine. . By these methods, the belt-shaped long fiber nonwoven fabric is wound up to an outer diameter of about 1.5 to 3 times the inner diameter of the second filtration layer 2 to form a filter cartridge. This may be used as it is as the filter cartridge 3, or the end face may be adhered to the housing on the end face of the filter cartridge by attaching a foamed polyethylene gasket having a thickness of about 3 mm.

The porosity of the first filtration layer thus formed is preferably in the range of 65 to 85%. If this value is less than 65%, the liquid density is lowered because the fiber density becomes too high. On the other hand, if this value exceeds 85%, the strength of the filter cartridge decreases, and problems such as deformation of the filter cartridge when the filtration pressure is high are likely to occur.

In the present invention, the liquid permeability of the resulting cartridge filter can be improved by making cuts or holes in the strip-shaped long fiber nonwoven fabric. In this case, the number of cuts is 10c
About 5 to 100 pieces are suitable per m, and when making holes, it is suitable to set the ratio of the area of the opening portion to about 10 to 80%. The filtration performance can also be adjusted by making the number of the strip-shaped long-fiber nonwoven fabrics at the time of winding up or winding together with other yarns such as spun yarns.

Next, the second filtration layer used in the present invention will be described.

The multi-layer filter made by the conventional technique has a problem in accuracy stability and filtration life because the upstream layer (the layer corresponding to the first filtration layer of the present invention) has a problem. Or, it was such that the filter material was dropped off or other foreign matter was mixed in the filtrate. In the present invention, since those problems are solved by devising the first filtration layer as described above, basically the problem is that the second filtration layer is a filter with higher accuracy than the first filtration layer. However, the initial 80% trapped particle diameter of the second filtration layer is preferably in the range of 0.05 to 0.9 times the initial 80% trapped particle diameter of the first filtration layer. If this value is less than 0.05, the collection ability of the first filtration layer and the second filtration layer becomes too different, so most of the particles cannot be captured by the first filtration layer, and the particles on the surface of the second filtration layer are not captured. It is not preferable because it may cause clogging. On the other hand, when this value exceeds 0.9 times, there is almost no difference in the trapping ability between the first filtration layer and the second filtration layer, so there is almost no point in dividing into a plurality of layers. The optimum value of this value cannot be generally stated because it depends on the particle size distribution in the pre-filtration liquid, but in general, when the pre-filtration liquid contains particles of various sizes, this It is preferable to decrease the value, and conversely, it can be said that it is preferable to increase the value when the pre-filtration liquid contains relatively uniform particles. Hereinafter, examples of the filtration layer useful as the second filtration layer will be given.

As one useful as the second filtration layer, a perforated sheet wound around a perforated tubular body in a roll shape can be used. Examples of the perforated sheet include non-woven fabric, woven fabric, membrane sheet, filter paper, and wire mesh. The structure of this filter is shown in FIG. An injection-molded perforated plastic core, a metal processed product such as stainless steel, or the like can be used for the perforated tubular body 26, but is not particularly limited as long as it has a strength that can withstand the filtration pressure. The perforated sheet 27 may be wound in a paste-like shape without any problem as long as the initial 80% trapped particle size can be achieved, and a known method such as a melt blown nonwoven fabric is used to determine the basis weight and fiber diameter of the nonwoven fabric. If there is, JP-A-10-17
The method described in Japanese Patent No. 4822 can be applied. Also,
When the perforated sheet is wound directly on the perforated tubular body, the surface area of the perforated sheet becomes small. Therefore, the size of the outer circumference of the perforated tubular body is about 5 to 20% of the outer diameter of the entire filter cartridge. A three-layer structure in which a third filtration layer having the same structure as the filtration layer is provided may be used. Moreover, since it takes a lot of man-hours depending on the manufacturing method to wrap it in a roll shape, it is possible to form the non-woven fabric into a tubular shape in advance and simply cover it with the core. Further, two or more kinds of non-woven fabrics having different fiber diameters and porosities may be wound stepwise as long as the effect of the present invention is not impaired.

Another useful second filter layer is one having a structure as shown in FIG. That is,
A filtration layer 28, which is formed by winding a band-shaped long-fiber non-woven fabric, which is made of a thermoplastic fiber around at least a part of its fiber intersections, around a perforated tubular body 26 in a cylindrical twill shape, and a perforated sheet 27 are glued. It is possible to use a two-layer structure having a filtration layer 29 in which a continuous filament long-fiber nonwoven fabric is wound in a cylindrical shape in a twill shape while being continuously wound from the filtration layer 28. This filter is similar to the filter shown in FIG. 16 described above, but the second filtration layer 27 of FIG. 16 is formed by winding only the perforated sheet, while the second filtration layer 27 of FIG. The difference is that the filter layer 29, which is a part, has a winded long-fiber nonwoven fabric inserted between the perforated sheets due to the manufacturing method.

As another useful one of the second filtration layers, there may be mentioned one formed by bending a perforated sheet around a perforated tubular body in a pleat shape to form a tubular shape. The structure of this filter is shown in FIG. Similarly, examples of the perforated sheet include non-woven fabric, woven fabric, membrane sheet, filter paper, and wire mesh. A known method for processing those perforated sheets,
For example, the method described in JP-A-6-262013 can be used. When this is used, since the surface area of the filter medium is large, the filter has excellent water permeability.

As another useful one of the second filtration layers, the thermo-adhesive conjugate fibers composed of two kinds of thermoplastic resins having a melting point difference of 10 ° C. or more are adhered and the intersections of the thermo-adhesive conjugate fibers are adhered. A cylindrical molded body can be mentioned. The structure of this filter is shown in FIG. When this filter medium is used, the fiber intersections of the second filter layer 31 are adhered, so that even if the filtration pressure rises, the collected particles are less likely to flow out, which is excellent. As a method for molding the tubular molded body, a known method, for example, a method described in JP-B-56-43139 and JP-A-4-126508 can be used.

[0063]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. In addition, the evaluation of the physical properties and filtration performance of the filtering material in each example was performed by the methods described below. The evaluation results are shown in Tables 1 and 2.

(Basis weight and thickness of non-woven fabric) The non-woven fabric was cut out so that the area of the non-woven fabric was 625 cm ^2, and its weight was measured and converted into weight per square meter to obtain a basis weight. Further, the thickness of the cut non-woven fabric was arbitrarily measured at 10 points, and the average of 8 points excluding the maximum value and the minimum value was taken as the thickness (μm) of the non-woven fabric.

(Fineness of Nonwoven Fabric) Five random samples were taken from the nonwoven fabric and photographed with a scanning electron microscope. Twenty fibers were randomly selected per one site, and their fiber diameters were measured. The average value was used as the fiber diameter (μm) of the nonwoven fabric. Further, the fineness (dtex) was obtained from the following equation using the obtained fiber diameter and the density (g / cubic centimeter) of the raw material resin for the nonwoven fabric. (Fineness) = π (fiber diameter) ² × (density) / 400

After fixing the cross-sectional shape of the pleated material with an adhesive, it was cut at five arbitrary positions and the cross-section was photographed with a microscope. From the photograph, the number of folds of the belt-shaped long-fiber nonwoven fabric was counted as 1 in both mountain folds and valley folds, and one half of the average number of 5 cuts was taken as the number of folds.

(Cross-sectional area and porosity of band-shaped long-fiber non-woven fabric bundle) After fixing the cross-sectional shape of the band-shaped long-fiber non-woven fabric bundle with an adhesive, it is cut at 5 positions at arbitrary positions and the cross-section is photographed with a microscope. did. The photograph was image-analyzed to determine the cross-sectional area of the band-shaped long-fiber nonwoven fabric bundle. In addition, a band-shaped long-fiber nonwoven fabric bundle at a position different from this was cut into a length of 10 cm, and the porosity was calculated from the weight and the previously determined cross-sectional area using the following formula. (Appearance volume of band-shaped long-fiber nonwoven fabric bundle) = (Cross-sectional area of band-shaped long-fiber nonwoven fabric bundle x cutting length of band-shaped long-fiber nonwoven fabric bundle) (True volume of band-shaped long-fiber nonwoven fabric bundle) = (Band-shaped long-fiber nonwoven fabric bundle) (Weight of the bundle) / (specific gravity of the raw material of the bundle of long-fiber nonwoven fabrics) (porosity of the bundle of long-fiber nonwoven fabrics) = {1- (true volume of the bundle of long-fiber nonwoven fabrics) / (long-fiber nonwoven fabric of the strips) Apparent volume of the focus)} × 100%

(Yarn Interval) A strip-shaped long-fiber nonwoven fabric adjacent to a band-shaped long-fiber nonwoven fabric bundle (or a strip-shaped long-fiber nonwoven fabric, spun yarn or the like wound around a perforated tubular body in the following examples) on the surface layer The distance from the bundle (shown by 32 in FIG. 1) was measured at 10 points per filter cartridge, and the average was taken as the yarn interval.

(Porosity of First Filtration Layer) The outer diameter, inner diameter, length and weight of the first filtration layer were measured, and the porosity was determined using the following formula. The weight was measured by taking out only the first filtration layer from the filter manufactured under the same conditions. (Apparent volume of first filtration layer) = π {(outer diameter of first filtration layer) ² − (inner diameter of first filtration layer) ² } × (length of first filtration layer) / 4 (first filtration layer True volume) = (weight of first filtration layer) / (specific gravity of raw material of first filtration layer) (porosity of first filtration layer) = {1- (true volume of first filtration layer) / first filtration Layer apparent volume)} × 100%

(Initial Collection Particle Size, Initial Pressure Loss, Filtration Life) One filter cartridge is attached to the housing of a circulation type filtration performance tester, and the flow rate is adjusted to 30 liters per minute by a pump to circulate water. The pressure loss before and after the filter cartridge at this time was made into the initial pressure loss. Next, 8 types of test powder I defined in JIS Z 8901 (abbreviated as JIS type 8) in circulating water (medium diameter: 6.
6 to 8.6 μm) and the same 7 types (abbreviated as JIS 7 type, medium diameter: 27 to 31 μm) at a weight ratio of 1: 1 were continuously added at a rate of 0.4 g / min, and from the start of addition After 5 minutes, the pre-filtration liquid and the filtration liquid were collected, diluted with an appropriate magnification, and the number of particles contained in each liquid was measured by a light-blocking particle detector to calculate the initial collection efficiency at each particle size. did.
Further, the value was interpolated to obtain a particle size showing a collection efficiency of 80%. Further, the cake was added continuously, and when the pressure loss of the filter cartridge reached 0.2 MPa, the pre-filtration liquid and the filtrate were collected in the same manner to determine the trapped particle size at 0.2 MPa. In addition, 0.2 from the start of cake addition
The time until reaching MPa was defined as the filtration life. In addition,
Differential pressure of 0.2 MPa even when the filtration life reaches 1000 minutes
If the measured value did not reach, the measurement was stopped at that point. The initial 80% trapped particle size of each layer was measured by using a perforated plastic molded product having a hollow interior as a dummy as described above, and making only each layer under the same conditions.

(Foaming of initial filtrate and loss of fibers) One filter cartridge is attached to the housing of a circulation type filtration performance tester, and the flow rate is adjusted to 10 liters per minute by a pump to pass ion-exchanged water. 1 liter of the initial filtrate was sampled, 25 cubic centimeters of which were sampled in a colorimetric bottle and vigorously stirred, and bubbling was observed 10 seconds after the stirring was stopped. Then, when the volume of the bubble (volume from the liquid surface to the apex of the bubble) is 10 cubic centimeters or more, x 10
5 bubbles less than a cubic centimeter and with a diameter of 1 mm or more
The occurrence of bubbles was judged as Δ when the number of bubbles was 1 or more, and when the number of bubbles having a diameter of 1 mm or more was less than 5. Further, 500 cubic centimeters of the initial filtrate is passed through a nitrocellulose filter paper having a pore size of 0.8 μm, and when there are four or more fibers of the filter mm or more described in the length 1 per square centimeter of the filter paper, x, and the case of 1 to 3 The loss of the fiber was judged as Δ, and when 0 was indicated as ◯.

(Example 1) An inner diameter of 30 was used as the second filtration layer.
mm, outer diameter 34 mm, length 250 mm, and a basis weight of 50 g / m ² around a perforated cylindrical body which is an injection-molded polypropylene product having 180 6 mm square holes.
A polypropylene melt-blown non-woven fabric having a thickness of 300 μm and a fiber diameter of 2 μm was wound into 1.1 rolls. Further, as a long-fiber non-woven fabric for a band-shaped long-fiber non-woven fabric, a basis weight of 22 g / m ² , a thickness of 200 μm, and a fineness of 2 dt
ex was used, and a polypropylene spunbonded nonwoven fabric whose fiber intersection was thermocompression bonded with a hot embossing roll was used. The long fiber non-woven fabric was slit into a width of 50 mm to obtain a strip-shaped long fiber non-woven fabric. Then, the second filtration layer is installed on the bobbin of the winder, and a guide of a circular hole with a diameter of 5 mm is installed on the yarn path to the winder, and the strip-shaped long fiber nonwoven fabric is about 5 mm in diameter.
And the spindle initial speed of 1500 rp on the second filtration layer.
In m, the number of winds was adjusted so that the distance between the strip-shaped long-fiber nonwoven fabrics was 1 mm, and the tape was wound around a perforated cylindrical body until the outer diameter became 62 mm, to obtain a cylindrical filter cartridge 3 as shown in FIG. .

(Example 2) A cylindrical filter cartridge was obtained in the same manner as in Example 1 except that the long fiber non-woven fabric was slit into a width of 10 mm and the number of winds was adjusted so that the yarn interval was 1 mm. This filter has the same performance as that of Example 1. However, the winding time was longer than that in Example 1.

Example 3 As a constituent fiber of a long fiber non-woven fabric, a low melting point component was a linear low density polyethylene (melting point: 12
Cylindrical filter cartridge was obtained in the same manner as in Example 1 except that the sheath-core type composite fiber having a high melting point of polypropylene and a weight ratio of 5: 5 was used. This filter has a longer filtration life than the filter described in Example 1. It is considered that this is because the fiber intersections of the first filtration layer are firmly adhered to each other, so that the collection ability of the first filtration layer is stabilized and the load on the second filtration layer is reduced.

(Example 4) A cylindrical filter cartridge was obtained in the same manner as in Example 3 except that the method for heat-bonding the fiber intersections was changed from a hot embossing roll to a hot-air circulating heating device. This filter was a filter having a slightly shorter filtration life than the filter described in Example 3. It is considered that this is because the adhesion of the fiber intersections of the first filtration layer was not as strong as in Example 3.

(Example 5) The fineness of the long fiber non-woven fabric was 10d.
A cylindrical filter cartridge was obtained in the same manner as in Example 1, except that the tex was changed. This filter has a shorter filtration life than the filter described in Example 1.

(Example 6) A cylindrical filter cartridge was obtained in the same manner as in Example 1 except that the belt-shaped long fiber non-woven fabric was not bundled, but instead twisted 100 times per 1 m. This filter was a filter having the same performance as the filter described in Example 1.

(Embodiment 7) A belt-shaped long fiber non-woven fabric is shown in FIG.
It was processed into a cross-sectional shape as shown in (A) to obtain a pleated material having four pleats. A cylindrical filter cartridge was obtained in the same manner as in Example 1 except that the pleated material was used instead of the bundled long fiber nonwoven fabric. This filter had a slightly longer filtration life than the filter described in Example 1, but the pressure loss was large. The pressure loss was larger than that of the filter described in Example 1 because the pleats were parallel to each other, and therefore the filtration pressure was applied from the direction perpendicular to the folds to reduce the porosity of the filter medium. This is because

(Embodiment 8) A belt-shaped long fiber non-woven fabric is shown in FIG.
It was processed into a cross-sectional shape as shown in (A) to obtain a pleated material having 7 pleats. A cylindrical filter cartridge was obtained in the same manner as in Example 7, except that the pleats were used. Despite the fact that this filter has a longer life than the filter described in Example 1, it has an excellent water permeability equivalent to that of the filter described in Example 1.

(Example 9) A belt-shaped long fiber non-woven fabric is shown in FIG.
The cross-sectional shape as shown in (C) was processed to obtain a pleated material having 15 pleats. A cylindrical filter cartridge was obtained in the same manner as in Example 7, except that the pleats were used. Although this filter had a longer life than the filter described in Example 8, the water permeability was an excellent filter equivalent to that of the filter described in Example 1.

(Example 10) A cylindrical filter cartridge was obtained in the same manner as in Example 9 except that the number of pleats of the belt-shaped long-fiber nonwoven fabric was 41. Although this filter had a longer life than the filter described in Example 9, the water permeability was an excellent filter equivalent to that of the filter described in Example 1.

(Example 11) A cylindrical filter cartridge was obtained in the same manner as in Example 9 except that the band-shaped long fiber non-woven fabric was densely bundled so that the porosity of the pleats was 72%. This filter has a shorter life than Example 9.

Example 12 The same meltblown nonwoven fabric as in Example 1 was used as the nonwoven fabric for rolling up. The same belt-like long-fiber nonwoven fabric as in Example 1 was used. Then, around the same perforated cylindrical body as in Example 1, the strip-shaped long-fiber nonwoven fabric was wound in a twill shape under the same conditions as in Example 1 until the outer diameter became 45 mm. After that, the continuous filament long-fiber non-woven fabric was continuously wound in a twill shape, and the non-woven fabric for winding was wound in a lap shape for 1.1 turns. Subsequently, only the strip-shaped long-fiber nonwoven fabric was wound in a twill shape to an outer diameter of 62 mm to obtain a cylindrical filter cartridge. This filter was as accurate as that of Example 1, but slightly superior in water permeability. It is considered that this is because the non-woven roll-shaped non-woven fabric came to the outer peripheral side as compared with Example 1 and the non-woven fabric surface area increased.

(Example 13) Fiber diameter 1 μm, basis weight 30 g
A polypropylene meltblown non-woven fabric was prepared by compressing with a flat roll to a porosity of 50% at / m ² . 22 g / unit weight on both sides of the melt blown nonwoven fabric
A polypropylene spunbonded non-woven fabric having a fineness of ² dtex is superposed at m ² and pleated at a height of 8 mm, cut at a number of ridges of 75 and connected at both ends to form a tubular body. The second filtration layer was placed on the substrate. A first filtration layer was formed around it in the same manner as in Example 1, and
A cylindrical filter cartridge as shown in 8 was obtained.

(Example 14) Fineness 2 dtex, fiber length 6
4 mm, a sheath-core type composite fiber made of high-density polyethylene and polypropylene is made into a web with a card machine, heated to 145 ° C. with a far-infrared heater, and an outer diameter of 45 mm is given to a 1.5 kg slenderless mandrel per 1 m. Winding around
After cooling, the mandrel was pulled out to obtain a hollow cylindrical body. A cylindrical filter cartridge was obtained in the same manner as in Example 1 except that the hollow cylindrical body was used as the second filtration layer.

(Comparative Example 1) A polypropylene spun yarn of 2 mm in diameter spun from a fiber having a fineness of 3 dtex was used in place of the strip-shaped long-fiber non-woven fabric, and the yarn interval was 1 mm.
A cylindrical filter cartridge was obtained in the same manner as in Example 1. The filter cartridge had a significantly shorter filtration life than that of Example 1. Also, the initial filtrate had foaming.

(Comparative Example 2) A cylindrical filter cartridge was obtained in the same manner as in Example 1 except that one kind of filter paper specified in JIS P 3801 cut to a width of 50 mm was used instead of the strip-shaped long fiber nonwoven fabric. It was This filter cartridge had an initial collection particle size similar to that of Example 1, but had a large initial pressure loss and an extremely short filtration life.

(Comparative Example 3) 50 g of basis weight with a fineness of 5 dtex
/ M ² long-fiber non-woven fabric was slit into a width of 25 cm, and a linear pressure of 1.5 was applied around the same second filtration layer as in Example 1 in the form of a roll.
It was wound at kg / m to obtain a cylindrical filter cartridge. The initial collection particle size of this filter was similar to that of Example 1, but the water permeability was poor and the filtration life was short.

[0089]

[Table 1]

[0090]

[Table 2]

[0091]

INDUSTRIAL APPLICABILITY The filter cartridge of the present invention has liquid permeability, filtration life and filtration as compared with a filter cartridge in which spun yarn is wound in a twill shape as the first filtration layer or a non-woven fabric is wound in a roll shape. It is well balanced in characteristics such as accuracy stability. In particular, when folds of long-fiber non-woven fabric that are bundled so that at least a part of the folds are non-parallel, the folds and vertical filtration are more effective than the pleats that are parallel to the folds. Since pressure is less likely to be received, the folds will not be crushed and the filtration performance can be maintained more stably. In addition, it was excellent in that the filtrate did not contain impurities.

[Brief description of drawings]

FIG. 1 is a perspective view of a filter cartridge according to the present invention.

FIG. 2 illustrates a state in which a non-woven fabric is wound into a paste.

FIG. 3 is an explanatory diagram showing a foreign matter collection state by an embossed pattern of a long fiber nonwoven fabric.

FIG. 4 is an explanatory view showing a state in which a belt-shaped long fiber nonwoven fabric is wound as it is without being processed.

FIG. 5 is an explanatory view showing a state in which a belt-shaped long fiber nonwoven fabric is wound while being twisted.

FIG. 6 is an explanatory diagram showing a state in which a strip-shaped long fiber nonwoven fabric is passed through a small hole to be bundled and then wound.

FIG. 7 is a view showing a manner of processing a long continuous fiber nonwoven fabric into a pleated material with a pleating guide.

FIG. 8 is a cross-sectional view showing an example of a pleating guide used in the present invention.

FIG. 9 is a sectional view showing an example of a pleating guide used in the present invention.

FIG. 10 is an explanatory diagram showing an example of a cross-sectional shape of a pleated object which is not parallel to a fold.

FIG. 11 is an explanatory diagram showing an example of a cross-sectional shape of a pleated object parallel to the folds.

FIG. 12 is an explanatory diagram showing a positional relationship among a fold forming guide, a narrow rectangular hole, and a small hole.

FIG. 13 is a partially cutaway perspective view showing an example of a band-shaped long fiber non-woven fabric bundle according to the present invention.

FIG. 14 is a schematic diagram showing a particle collection state of a long fiber nonwoven fabric.

FIG. 15 is a schematic diagram showing a particle collection state of a short fiber non-woven fabric.

FIG. 16 is a perspective view showing an example of a filter cartridge according to the present invention.

FIG. 17 is a perspective view showing an example of a filter cartridge according to the present invention.

FIG. 18 is a perspective view showing an example of a filter cartridge according to the present invention.

FIG. 19 is a perspective view showing an example of a filter cartridge according to the present invention.

[Explanation of symbols]

1 First Filtration Layer 2 Second Filtration Layer 3 Filter Cartridge 4 Band-Long Fiber Nonwoven Fabric Concentrate 5 Part with Strong Thermocompression Bonding by Embossing Pattern 6 Part with Only Weak Thermocompression Bonding Due to Deviating from Embossing Pattern 7 Particle 8 Embossing Pattern Particles that have passed through the part where there is only weak thermo-compression due to being out of contact with the belt 9 Band-shaped long-fiber non-woven fabric or its bundle 10 Traverse guide 11 with narrow holes 11 Bobbin 12 Filter cartridge 13 Traverse guide 14 Traverse guide 15 External regulation guide 16 Internal regulation Guides 17 Small holes 18 Pleats 19 Pleat forming guides 20 Comb-shaped fold forming guides 21 Narrow rectangular holes 22 Strip-shaped long-fiber non-woven fabrics with a minimum area of eggs 23 Long-fibers 24 Particles 25 Short-fibers 26 Cylindrical with holes Body 27 Perforated sheet 28 Filtration wrapped in a twill Layer 29 Filtration layer in which twill-shaped long-fiber nonwoven fabric is wound while winding a perforated sheet 30 Perforated sheet 31 that has been fold-folded Cylindrical molded body 32 A band-shaped long-fiber non-woven fabric bundle and one layer below it Between the long-fiber non-woven fabric bundles wound on a wire

Claims (15)

(57) [Claims] 1. A first filtration layer formed by winding a strip-shaped long-fiber non-woven fabric made of a thermoplastic fiber and having at least a part of its fiber intersections bonded to each other in a twill shape in a cylindrical shape, and an initial 80%.
The collection particle size is 0.05 of the initial 80% collection particle size of the first filtration layer.
A filter cartridge comprising a second filtration layer that is ~ 0.9 times. 2. The filter cartridge according to claim 1, wherein the thermoplastic fiber comprises a low melting point resin and a high melting point resin, and the melting point difference between the two resins is 10 ° C. or more. 3. The filter cartridge according to claim 2, wherein the low melting point resin is linear low density polyethylene and the high melting point resin is polypropylene. 4. The filter cartridge according to any one of claims 1 to 3, wherein the belt-shaped long-fiber nonwoven fabric is bonded at its fiber intersections by thermocompression bonding with a hot embossing roll. 5. The filter cartridge according to any one of claims 1 to 3, wherein the band-shaped long-fiber nonwoven fabric is bonded at its fiber intersections with hot air. 6. The filter cartridge according to claim 1, wherein the belt-shaped long-fiber nonwoven fabric is twisted. 7. A belt-shaped long-fiber non-woven fabric is formed into a pleated material having 4 to 50 pleats in a cross section of the pleated material, and is wound around the perforated tubular body in a twill shape. The filter cartridge according to item. 8. The filter cartridge according to claim 7, wherein at least some of the pleats of the pleats are non-parallel. 9. The filter cartridge according to claim 7, wherein the porosity of the pleats is 60 to 95%. 10. The filter cartridge according to claim 1, wherein the first filtration layer of the filter cartridge has a porosity of 65 to 85%. 11. A strip-shaped long-fiber nonwoven fabric is obtained by slitting a wide-width long-fiber nonwoven fabric and has a width of 0.5 cm or more. filter cartridge according to any one of claims 1 to 10, the product of the nonwoven basis weight (g / m ²⁾ is 200 or less. 12. The filter cartridge according to claim 1, wherein the second filtration layer is formed by winding a perforated sheet around the perforated tubular body in a roll shape. 13. A strip-shaped long-fiber non-woven fabric in which a second filtration layer is composed of a thermoplastic fiber around a perforated tubular body and at least a part of its fiber intersections are adhered is wound in a cylindrical twill shape. It is a two-layer structure comprising a filter layer and a filter layer in which a band-shaped long-fiber nonwoven fabric is continuously wound in a cylindrical shape in a twill shape from a filter layer while winding a perforated sheet in a roll shape. The filter cartridge according to claim 1, wherein the layer is a filtration layer obtained by continuously winding a belt-shaped long-fiber nonwoven fabric in a cylindrical shape in a twill shape from the second filtration layer. 14. The filter cartridge according to claim 1, wherein the second filtration layer is formed into a tubular shape by bending a perforated sheet around the perforated tubular body in a pleat shape. 15. The second filtration layer has a melting point difference of 2 ° C. or more.
The filter cartridge according to claim 1, wherein the filter cartridge is a tubular molded body that is composed of a heat-adhesive conjugate fiber made of a thermoplastic resin of a kind and is bonded at an intersection of the heat-adhesion conjugate fiber.