JP2001000812A - Filter cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the smoothness at end faces and to solve the sealing defect of elasticity at the time of sealing by providing both ends of a filter cartridge, which is constituted by cross winding belt-like nonwoven fabrics consisting of thermoplastic fibers around a perforated cylindrical body, and providing end face with sealing parts. SOLUTION: Both ends of the filter cartridge 1 which is constituted by cross winding the belt-like nonwoven fabrics consisting of the thermoplastic fibers around the perforated cylindrical body are provided with the end face sealing parts which are smooth and have the elasticity at sealing. At this time, the thermoplastic fibers after to the fibers consisting of a thermoplastic resin and the belt-like nonwoven fabric refers to the nonwoven fabrics narrow in width which are formed by cutting, etc., of a nonwoven fabric having a large width. The perforated cylindrical body 2 refers to the cylindrical body which plays the role of a core material of the filter cartridge 1. Further, the filter cartridge 1 is formed by putting the bundled belt-like nonwoven fabrics 3 in congestion into the cartridge and integrating the bundled belt-like nonwoven fabric 7 near the ends with the fused parts 4 to improve the smoothness and elasticity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical filter cartridge for liquid filtration having excellent adhesion to a housing.

[0002]

2. Description of the Related Art At present, various filters have been developed and produced for purifying fluids. Above all, cylindrical cartridge type filters (hereinafter abbreviated as filter cartridges), in which filter media can be easily replaced, are used for removing suspended particles in industrial liquid raw materials, removing cake flowing out of a cake filtration device, and purifying industrial water. It is used in a wide range of industrial fields.

Several types of filter cartridges have been proposed. The most typical one is a wound filter cartridge utilizing spun yarn. This is a cylindrical filter cartridge made by winding a spun yarn as 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.

[0004] In such a conventional method for collecting foreign matter of a thread wound filter cartridge, foreign matter is collected by fluff generated from spun yarn, and foreign matter is entangled in a gap between the spun yarns. Since it is difficult to adjust the size and shape of the fluff and the gap, there is a disadvantage that the size and amount of foreign matter that can be collected are limited. Further, since the spun yarn is made from short fibers, there is a disadvantage that constituent fluids of the spun yarn fall off when a fluid flows through the filter cartridge. Further, since spun yarn is produced by spinning short fibers, at least two steps of spinning and spinning of short fibers are required, and as a result, the price may be increased.

Further, the end face of the conventional thread-wound filter cartridge is inferior in smoothness because the so-called spun yarns are arranged. Further, in order to spin the yarn, it is necessary to wind the yarn hard, so that the end surface is also hard, the penetration of the edge of the housing is deteriorated, and the sealing performance of the end surface is poor.

[0006] In order to solve such a drawback, some contrivances have been made conventionally. One method was to heat bond the end faces of the filter. Due to the thermal bonding of the end face, the thread of the filter cartridge was not loosened.However, this was mainly for the purpose of preventing the thread from being unraveled, and there was still a problem with the smoothness and sealing property of the end face as described above. I was

As another method, there is a method of attaching a cushion material to an end face of a filter. It is made of foam material such as foamed polyethylene, foamed polypropylene, ethylene propylene rubber, low density polyethylene film,
The bonding is performed using a binder such as a low molecular weight polypropylene or an ethylene vinyl acetate resin. The use of this method solves the problems of smoothness and sealability of the end face. However, when a new material is added in this way, the use conditions of the filter, such as temperature conditions and chemical resistance, are restricted by the filter material, cushion material, and cushion material binder material. There is a drawback that the usable fields are limited. In particular, since the binder often has poor heat resistance and chemical resistance, the binder may be peeled off depending on the use conditions. In addition, binders used for such applications generally contain low molecular weight components in many cases, so that problems remain when used not only for medicines and foods but also for general industrial use. Another problem is that the cost of the filter is increased by attaching such a cushioning material. Japanese Utility Model 4-87717
Japanese Patent Application Publication No. JP-A-2005-13387 discloses a method of using a synthetic resin film wound around both ends of a filter as a binder to prevent the cushioning material from peeling off when the paint is filtered, but this method occurs when a spun yarn is wound up. The glass fiber nonwoven fabric is intended to solve the problem of curling, and does not necessarily solve all of the problems described above.

As another method, Japanese Patent Application Laid-Open No. 4-45810 discloses that a slit nonwoven fabric made of a conjugate fiber in which 10% by weight or more of constituent fibers is divided into 0.5 denier or less is placed on a porous core tube. Fiber density 0.18-0.30g /
A filter wound to have a size of cm ³ has been proposed. When this method is used, the non-woven fabric is used in place of the spun yarn, and thus it is considered that the smoothness of the end face as described above is slightly improved. However, it is necessary to use physical stress such as high-pressure water to split the conjugate fiber, and the physical stress used for splitting may reduce the strength of the nonwoven fabric. However, this does not solve the problem of poor sealing performance of the end face.

As another method, Japanese Patent Publication No. 8-29206 discloses a method in which a thermoplastic sheet is bonded to an end face of a filter element made of thermoplastic synthetic fiber by a hot plate. However, this method is a method for maximizing the sealing property of the end of the original filter element, and is not always satisfactory when the original filter element lacks a potential sealing property (for example, softness). It was not something.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problem of the conventional filter, that is, poor sealing property due to lack of smoothness of the end face and elasticity at the time of sealing.

[0011]

The present invention has the following arrangement to solve the above-mentioned problems. (1) A filter cartridge in which end-face sealing portions are provided at both ends of a filter cartridge obtained by winding a belt-shaped nonwoven fabric made of a thermoplastic fiber around a perforated tubular body in a twill shape. (2) The filter cartridge according to the above (1), wherein the end face sealing portion is formed by welding a band-shaped nonwoven fabric forming both end portions of the filter cartridge. (3) A sheet made of the same resin as at least one kind of thermoplastic resin, which is a component of the thermoplastic fiber used for the belt-shaped nonwoven fabric forming the both ends, is attached to both end surfaces of the filter cartridge in which the end face seal portions are formed. -The filter cartridge according to the above (1), which is formed by welding. (4) Any one of the above items (1) to (3), wherein the width of the band-shaped nonwoven fabric is 0.5 cm or more, and the product of the width (cm) of the band-shaped nonwoven fabric and the basis weight (g / m ² ) is 200 or less. The filter cartridge according to the item. (5) The thermoplastic fibers constituting the belt-shaped nonwoven fabric are composed of a low-melting resin and a high-melting resin, and the difference between the melting points of the two resins is 10
(1) to (1) which are heat-adhesive conjugate fibers having a temperature of at least
(4) The filter cartridge according to any one of the above (4). (6) the low melting point resin is a linear low density polyethylene;
The filter cartridge according to the above (5), wherein the high melting point resin is polypropylene. (7) The filter cartridge according to any one of (1) to (6), wherein the belt-shaped nonwoven fabric is a long-fiber nonwoven fabric made by a spunbond method. (8) The porosity of the filter cartridge is 65 to 85%
The filter cartridge according to any one of the above items (1) to (7), wherein

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described specifically.

The filter cartridge of the present invention has a smooth and elastic sealing end face sealing portion at both ends of a filter cartridge obtained by winding a band-shaped nonwoven fabric made of thermoplastic fiber around a perforated cylindrical body in a twill shape. It is a provided filter cartridge. In the present invention, the end face seal portion is a smooth film-shaped portion provided integrally with both end portions of the filter cartridge. By providing this end face seal portion, a cylindrical filter cartridge for liquid filtration having excellent adhesion to the housing can be obtained.

The thermoplastic fibers referred to in the present invention are fibers made of a thermoplastic resin. In the present invention, any thermoplastic resin that can be melt-spun can be used, and examples thereof include polypropylene, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, and copolymerized polypropylene (for example, mainly propylene, ethylene, Polyolefin resins such as binary or multi-component copolymers with butene-1,4-methylpentene-1 and the like;
Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, low-melting polyesters obtained by copolymerizing an acid component with isophthalic acid in addition to terephthalic acid, polyamide resins such as nylon 6, nylon 66, and polystyrene (Attack) Thermoplastic resins such as polystyrene, syndiotactic polystyrene), polyurethane elastomers, polyester elastomers, and polytetrafluoroethylene. In addition, a functional resin may be used, such as using a biodegradable resin such as a lactic acid-based polyester to make the filter cartridge biodegradable. In addition, when using a resin that can be polymerized with a metallocene catalyst such as a polyolefin resin or polystyrene, using a resin polymerized with a metallocene catalyst can improve the properties of the metallocene resin, such as improving nonwoven fabric strength, improving chemical resistance, and reducing production energy. Is preferable because it is utilized in the filter cartridge. These resins may be blended and used in order to adjust the thermal adhesiveness and rigidity of the long-fiber nonwoven fabric. Among these, polyolefin resins such as polypropylene are preferable from the viewpoint of chemical resistance and price when the filter cartridge is used for filtration of an aqueous liquid at room temperature, and when used for a relatively high temperature liquid. Polyester-based resins, polyamide-based resins, syndiotactic polystyrene and the like are preferred.

The band-shaped nonwoven fabric referred to in the present invention is a narrow nonwoven fabric, and a wide nonwoven fabric is slit (cut).
Or a non-woven fabric directly manufactured to be narrow. In order to obtain stable quality at low cost, it is preferable to slit a wide range of nonwoven fabric.

The width of the band-shaped nonwoven fabric varies depending on the basis weight of the nonwoven fabric used, but is preferably 0.5 cm or more.
If this width is smaller than 0.5 cm, the nonwoven fabric may be cut, and it is difficult to adjust the tension when winding the band-shaped nonwoven fabric in a twill shape later. , The winding time becomes longer and the productivity decreases. On the other hand, the upper limit of the width of the band-shaped nonwoven fabric varies depending on the basis weight, and the value of the width (cm) × the basis weight (g / m ² ) of the band-shaped nonwoven fabric is preferably 200 or less. This value is 200
If it is larger than this, the rigidity of the band-shaped nonwoven fabric becomes too large, so that it is difficult to wind the band-shaped nonwoven fabric around the perforated tubular body later, and furthermore, it becomes too thick when bundled, so that it is difficult to wind tightly.

Further, the basis weight of the band-shaped nonwoven fabric, that is, the nonwoven fabric
Weight per unit area is 5-200 g / m^TwoIs preferred
No. This value is 5 g / m^TwoIf it is smaller than
The non-woven fabric becomes uneven,
Or the strength of the nonwoven fabric is reduced,
Wearing can be difficult. On the other hand, this value is 200 g /
m ^TwoLarger, the rigidity of the band-shaped nonwoven fabric increases.
Because it is too hard to wind
It becomes.

The perforated tubular body (2 in FIG. 1) referred to in the present invention serves as a core material of the filter cartridge, and its material and shape have strength enough to withstand an external pressure during filtration. There is no particular limitation as long as the pressure loss is not extremely high.For example, an injection molded product obtained by processing polyethylene or polypropylene into a net-like cylindrical shape, such as a core material used in a normal filter cartridge, may be used.
Also, ceramics, stainless steel, and the like may be processed in the same manner. Alternatively, other filter cartridges, such as a fold-folded filter cartridge as a perforated cylindrical body or a nonwoven fabric wound-type filter cartridge, may be used.

Next, a method of winding the band-shaped nonwoven fabric around the perforated cylindrical body will be described. FIG. 9 shows an example of the manufacturing method. The winder used for a normal thread-wound filter cartridge can be used for the winding machine. A bobbin 11 of this winder has a diameter of about 10 to 40 mm and a length of 100 mm.
The perforated tubular body 2 having a size of about 1000 mm is mounted, and the band-shaped nonwoven fabric 3 bundled through the thread path of the winder and the hole of the traverse guide 12 is wound around the perforated tubular body for about 1 to 2 turns. The perforated tubular body and the end portion of the belt-shaped nonwoven fabric may be bonded to each other by thermal bonding or the like in order to reliably perform winding. Since the yarn path of the winder is traversed by the traverse guide 12 installed in parallel with the bobbin, the band-shaped nonwoven fabric is wrapped around the perforated tubular body in a traverse shape by the rotation of the bobbin. The diameter of the hole provided in the traverse guide 12 depends on the basis weight and width of the band-shaped nonwoven fabric to be used.
The range of mm is preferred. When the diameter is smaller than 3 mm, the friction between the band-shaped nonwoven fabric and the holes becomes large, and the winding tension becomes too high. If this value is larger than 10 mm, the convergence size of the band-shaped nonwoven fabric becomes unstable.

The winding condition of the band-shaped nonwoven fabric may be set in accordance with the production of a normal thread-wound filter cartridge. For example, the initial speed of the bobbin is set to 1000 to 2000 rpm.
What is necessary is just to wind it while adjusting a feeding speed and applying an appropriate tension. The porosity of the filter cartridge can also be changed by the tension at this time. The filtering accuracy can also be changed by adjusting the ratio between the traverse speed of the traverse guide and the rotation speed of the bobbin to change the winding pattern. The method of applying the pattern can use a known thread wound filter cartridge method which is already known, and when the length of the filter is constant, the pattern can be represented by the number of winds. In addition,
The wind number indicates the number of rotations of the bobbin 11 until the traverse guide 12 moves from one end of the bobbin 11 to the other end. In addition, when the space | interval 5 of a certain thread | yarn (the belt-shaped nonwoven fabric in the case of this invention) and the thread | yarn wound under one layer is wide, filtration accuracy becomes coarse, and conversely, when it is narrow, it becomes fine. According to these methods, the band-shaped nonwoven fabric is cut into the outer diameter of the perforated cylindrical body 2 of 1.5 times.
Wrap to an outer diameter of about 2 to 3 times to form a filter cartridge.

In the present invention, the end face seal portion is preferably formed by welding a band-shaped nonwoven fabric constituting both ends of the filter cartridge (hereinafter, referred to as both end portions of the filter). Since the is integrated with the filter cartridge, problems such as peeling do not occur. One example is shown in FIG.

Next, a method for forming an end face sealing portion by welding a band-shaped nonwoven fabric forming both end portions of the filter will be described. The welding of the band-shaped nonwoven fabric forming the filter both ends is performed by melting the band-shaped nonwoven fabric by heat, a solvent, ultrasonic waves, etc., and then solidifying while shaping the shape into a smooth end face, whereby the end face sealing portion is formed. It is formed. In the present invention, since a belt-shaped nonwoven fabric made of thermoplastic fibers is used, a method using heat is preferable. Examples of the heating method in this case include a method in which heating is performed using hot air, infrared light, or the like, and a method in which heating is performed directly by contacting with a hot plate. Either method can be used for heating, but in view of the smoothness of the end face and the ease of setting the heating conditions, a method of directly heating by contacting with a hot plate is preferable. FIG. 1 shows an example of the filter cartridge thus manufactured.

The degree of this heating is preferably such that the thickness of the welded portion at both ends of the filter is 10 μm to 1000 μm. Here, the thickness of the welded portion refers to the thickness of the portion where the fibers of the original band-shaped nonwoven fabric are formed into a film by welding. One example is shown in FIG. When the heating is small, the smoothness of both ends of the filter is reduced due to insufficient welding of the band-shaped nonwoven fabric, and therefore, there is no point in performing the heating. Conversely, if this heating is too much, both ends of the filter become hard, so that the elasticity at the time of sealing deteriorates, which is not preferable. The heating conditions vary depending on the resin used and the heating method, so it cannot be said unconditionally. However, the melting point of the thermoplastic resin used (if a material consisting of two or more components is used, the melting point of the low melting point component therein) The heating is about 1 to 10 seconds at a temperature higher by about 5 to 20 ° C. than the above.

By this processing, a smooth end face sealing portion is formed at both ends of the filter, so that the sealing performance is improved. This effect is not obtained only by simply forming both ends of the filter into a film. FIG. 3 is a partially cutaway view of the filter cartridge obtained by this method, and FIG. 5 is an enlarged view of its end. As shown in FIG. 3, this filter cartridge has a shape in which the band-shaped nonwoven fabric 3 converged therein is densely packed. Each of the bundled band-shaped nonwoven fabrics 3 has a moderate elasticity as compared with spun yarn or the like. Therefore, this filter cartridge is excellent in the sealing property at the end compared with the filter cartridge made of spun yarn without welding the end face. Furthermore, the filter cartridge of the present invention has a structure in which the banded nonwoven fabric 7 near the end is integrated with the welded portion 4 at the end as shown in FIG. It is excellent. On the other hand, FIG. 7 is an enlarged cross-sectional view of an end portion of a thread-wound filter cartridge using a conventional spun yarn. At the end of the filter cartridge, the spun yarns are merely arranged, so that there are many irregularities and the sealing property is lacking. Also, even if the end of the wound filter cartridge using the spun yarn is heat-welded, the spun yarn is inferior in heat adhesion to the nonwoven fabric, and therefore, FIG.
As shown in (1), only the adjacent spun yarns are adhered to each other, and the unevenness at the end is not smoothed. At this time, even if the temperature is further increased, only a hard film is formed by the melted spun yarn, and the end face sealing portion does not have an appropriate elasticity as in the present invention.

[0025] Even if only the band-shaped nonwoven fabric forming both ends of the filter is welded in this way, a smooth end face sealing portion is formed and the sealing property is improved, but as shown in FIG. A band-shaped nonwoven fabric constituting the outer periphery of the side surface may be welded. Thereby, the shape stability of the filter cartridge is further improved. The welding length B is set so as not to extremely impair the liquid permeability of the filter cartridge. FIGS. 4 and 6 show a partially cutaway view and an enlarged view of the end of the filter cartridge, respectively.

On the other hand, the end face sealing portion does not weld the band-shaped non-woven fabric forming the both ends of the filter as it is by heating or the like, but attaches the thermoplastic non-woven fabric used for the band-shaped non-woven fabric forming the both ends to the filter both end surfaces. A sheet made of the same resin as at least one of the thermoplastic resins that are the components of the fiber may be attached, and if necessary, formed by welding. Here, for example, a propylene homopolymer and a propylene-α-olefin copolymer can be regarded as the same resin. Examples of the method of attaching include a method using a binder and a thermal bonding method, and a thermal bonding method that causes few problems such as peeling is preferable. The sheet is not particularly limited as long as it is in a sheet shape such as a film, a nonwoven fabric, and a woven fabric. Further, even if the resin used for the sheet is different from the thermoplastic resin which is a component of the thermoplastic fiber used for the belt-shaped nonwoven fabric, it can be used if the compatibility is high.

The fiber constituting the band-shaped nonwoven fabric used in the present invention is a composite fiber comprising a low melting point resin and a high melting point resin having a melting point difference of 10 ° C. or more, preferably 15 ° C. or more among the thermoplastic fibers. Is more preferable because the weldability of the steel is improved. There is no particular upper limit for the melting point difference, but among the thermoplastic resins that can be melt-spun, the temperature difference between the highest melting point resin and the lowest melting point resin corresponds. In the case of a resin having no melting point, the flow start temperature is regarded as the melting point. When a composite fiber composed of a low-melting resin and a high-melting resin is used as the fiber constituting the belt-shaped nonwoven fabric, the degree of welding can be easily adjusted, and the porosity at the end can be easily adjusted.

The combination of the low melting point resin and the high melting point resin of the conjugate fiber is not particularly limited as long as the difference in melting point is 10 ° C. or more, preferably 15 ° C. or more. Polypropylene, low density polyethylene / polypropylene, copolymer of propylene and other α-olefins / polypropylene, linear low density polyethylene / high density polyethylene,
Low density polyethylene / high density polyethylene, various polyethylene / thermoplastic polyester, polypropylene / thermoplastic polyester, copolymerized polyester / thermoplastic polyester, various polyethylene / nylon 6, polypropylene / nylon 6, nylon 6 / nylon 66, nylon 6 / Thermoplastic polyesters and the like. Among them, the use of a combination of linear low-density polyethylene / polypropylene is preferable because the rigidity and porosity of the nonwoven fabric and the end can be easily adjusted. When the obtained filter cartridge is used for filtration of a liquid having a relatively high temperature, a low-melting polyester / polyethylene terephthalate combination obtained by copolymerizing an acid component with isophthalic acid in addition to terephthalic acid is also preferably used. Can be.

The strip-shaped nonwoven fabric used in the present invention is more preferably a long-fiber nonwoven fabric obtained by a spunbond method. The spun bond method is a nonwoven fabric manufacturing technique in which thermoplastic fibers discharged from a nozzle are drawn by suction using an air gun or the like, spread on a conveyor, and then thermally bonded. In the long-fiber nonwoven fabric made of a thermoplastic resin obtained by the spunbonding method, the fiber direction is aligned with the machine direction as shown in FIG. It will be small. On the other hand, in the case of a nonwoven fabric made of short fibers obtained by a card method or the like, FIG.
Since the fiber direction is not constant as shown in the figure, the holes formed by the fibers 15 have a shape close to a circle or a square, and even if the opening ratio is the same as that of the long-fiber nonwoven fabric made by the spun bond method or the like, The maximum passing particle diameter 14 is large. Since the water permeability of the filter medium is substantially determined by the porosity if the fiber diameter is the same, a filter having excellent water permeability can be obtained by using a long-fiber nonwoven fabric made by a spunbond method or the like. Since this effect is reduced when a binder such as an adhesive that closes the pores of the filter material is used, the use of a cellulose spunbond nonwoven fabric is not preferable. In addition, the use of a cellulose spunbonded nonwoven fabric reduces the strength of the nonwoven fabric. Therefore, when the filtration pressure is increased due to clogging of a filter or the like, there is a problem that pores formed of fibers are easily deformed. On the other hand, the average single-fiber fineness of the long-fiber nonwoven fabric used in the present invention varies depending on the use of the filter cartridge and the type of the resin, so it is difficult to unconditionally define the average single-filament fineness.
The range of ex is desirable. When the fineness is 3000 dtex or more, there is no difference from a case where a continuous yarn is simply bundled, and there is no point in using a long-fiber nonwoven fabric. Further, by setting the dtex to 0.6 dtex or more, a sufficient strength of the nonwoven fabric can be obtained, so that the strength of the manufactured filter cartridge is increased, which is preferable. Further, when spinning a fiber having a fineness smaller than 0.6 dtex by the current spunbonding method, the workability and spinnability of the nozzle used are deteriorated, and as a result, the price of the manufactured spunbonded nonwoven fabric is high. May be.

Further, the constituent fibers of the long-fiber nonwoven fabric do not necessarily have to have a circular cross section, and a yarn having an irregular cross section may be used. In that case, the collection of the fine particles increases as the surface area of the filter increases, so that a filter cartridge having the same liquid permeability and high precision can be manufactured as compared with the case where a fiber having a circular cross section is used.

When a hydrophilic resin such as polyvinyl alcohol is mixed with the raw resin of the long-fiber nonwoven fabric, or the surface of the long-fiber nonwoven fabric is hydrophilized, for example, the obtained filter cartridge is made of an aqueous filter. When used for filtration of a liquid, the liquid permeability is improved. Therefore, when an aqueous solution is filtered, a filter using such a resin is preferable.

The method for thermally bonding the fiber intersections of the long-fiber nonwoven fabric used in the present invention includes a method of thermocompression bonding using a device such as a hot embossing roll and a hot flat calender roll, a hot air circulation type, and a hot through air type. , Infrared heater type,
A method using a heat treatment machine such as a vertical hot air jet type can be used. Among them, a method using a hot embossing roll is preferable because the production speed of the nonwoven fabric can be improved, the productivity is good, and the cost can be reduced.

Further, as shown in FIG. 12, the long-fiber nonwoven fabric made by the method using the hot embossing roll has only a portion 16 with strong thermocompression bonding by the embossing pattern and a weak thermocompression bonding by disengagement from the embossing pattern. There is a part 17 with. As a result, a large number of foreign substances 18 and 19 can be collected in the portion 16 where there is strong thermocompression bonding. On the other hand, in the portion 17 where the fiber intersections are almost not thermally bonded, a 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 filtration structure utilizing the inside of the filter medium is preferable.

In this case, the area of the emboss pattern is 5 to
It is desirable to set it to 25%. By setting the area to 5% or more, the effect of the thermal bonding at the fiber intersection as described above can be improved, and by setting the area to 25% or less, it is possible to suppress the rigidity of the nonwoven fabric from becoming too large. Alternatively, it is possible to make it easier for the foreign matter to pass through the long-fiber nonwoven fabric to some extent, and to catch the foreign matter that has passed inside the filter, thereby extending the life of the filter.

Further, after processing into the shape of the filter cartridge by the method described later, the fiber intersection may be heat-bonded by infrared rays, steam treatment or the like. Alternatively, the fiber intersections can be chemically bonded using an adhesive such as an epoxy resin. However, compared with the case where heat bonding is performed, the porosity is lower, and the liquid permeability may decrease.

The porosity of the filter thus produced is preferably in the range of 65 to 85%. If this value is less than 65%, the fiber density becomes too high and the liquid permeability decreases. Conversely, if this value is greater than 85%, the strength of the filter cartridge is reduced, and problems such as deformation of the filter cartridge when the filtration pressure is high are likely to occur.

[0037]

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 each of the examples, the winders described below were used, and the evaluation of the physical properties, filtration performance, and the like of the filter media was performed by the methods described below.

(Winder) The traverse width (traverse width) is 250 mm, and the traverse guide (1 in FIG. 9)
A winder having a hole diameter of 5 mm in 2) was used. The spindle initial speed was set at 1500 rpm.

(Fabric Weight and Thickness of Nonwoven Fabric) The nonwoven fabric was cut out so that the area of the nonwoven fabric became 500 cm ² , the weight was measured, and the weight was converted into the weight per square meter to obtain the basis weight. The thickness of the cut nonwoven fabric was arbitrarily measured at 10 points, and the average of 8 points excluding the maximum value and the minimum value was defined as the thickness of the nonwoven fabric.

(Fineness of fibers of nonwoven fabric) Five samples were randomly sampled from the nonwoven fabric, photographed with a scanning electron microscope, and 20 fibers were randomly selected for each location to measure their fiber diameter. The average value was defined as the fiber diameter (μm) of the nonwoven fabric. The fineness (dtex) was determined from the following equation using the obtained fiber diameter and the density (g / cm ³ ) of the nonwoven fabric raw material resin. (Fineness) = π (fiber diameter) ² × (density) / 400

(Yarn spacing) The spacing (shown at 5 in FIG. 1) between the band-shaped nonwoven fabric on the surface layer and the adjacent band-shaped nonwoven fabric was measured at 10 places for one filter cartridge, and the average was taken as the yarn spacing.

(Void Ratio of Filter Cartridge) The outer diameter, inner diameter, length, and weight of the filter cartridge were measured, and the porosity was determined using the following equation. In order to determine the porosity of the filter medium itself, use the outer diameter of the perforated tubular body for the inner diameter value, and subtract the weight of the perforated tubular body from the weight of the filter cartridge for the weight value. Using. (Apparent volume of filter) = π ｛(outer diameter of filter) ^2- (inner diameter of filter) ² ｝ × (length of filter)
/ 4 (true volume of filter) = (weight of filter) / (specific gravity of raw material of filter) (porosity of filter) = {1− (true volume of filter) / apparent volume of filter} × 100%

(Initial Collection Particle Size and Sealing Property of End Face) One filter cartridge is attached to the housing of the circulating filtration performance tester, and the flow rate is adjusted to 30 liters per minute by a pump to circulate water. JIS Z 8 for circulating water
8 types of test powder I (abbreviated as JIS 8 types; median diameter: 6.6 to 8.6 μm) and 7 types (JIS)
Abbreviated as seven. (Medium diameter: 27-31 μm) with a weight ratio of 1: 1
Was added continuously at a rate of 0.4 g / min per minute, and the filtrate was collected 5 minutes after the start of the addition. The particles in the filtrate were separated by filtering 50 cm ³ of the filtrate through a nitrocellulose membrane filter paper having a pore size of 0.8 μm and having a ruled line of a grid of 5 mm. Ten grids were arbitrarily selected on the filter paper, and the circle-equivalent diameter of the largest particle existing in the grid was defined as the maximum passage particle size of the filter. On the other hand, the same measurement was performed by completely sealing the end surface of the filter cartridge made under the same conditions with an adhesive, and then completely bonding the housing and the filter cartridge with the adhesive so that there was no leakage from the end surface. The sealing performance was evaluated in comparison with the above results.

Example 1 A nonwoven fabric having a basis weight of 22 g /
A long-fiber nonwoven fabric having a m ² , a thickness of 200 μm, a fineness of 2 dtex, and a fiber intersection point obtained by a spunbond method made of polypropylene and thermocompression-bonded with a hot embossing roll was used. Further, as a perforated cylindrical body, an inner diameter of 30 mm and an outer diameter of 34 mm are used.
An injection molded product made of polypropylene having a length of 250 mm and a length of 250 mm and having 180 holes of 6 mm square was used. The long fiber nonwoven fabric was slit into a width of 50 mm to obtain a belt-shaped nonwoven fabric. Then, the band-shaped nonwoven fabric is bundled through the holes of the traverse guide of the winder and wound around a perforated cylindrical body until the outer diameter becomes 60 mm with a wind number of 3.955,
It was shaped into a cylindrical filter cartridge. The end face was welded with a hot plate having a surface temperature of 175 ° C. for 5 seconds to obtain a filter cartridge as shown in FIG.

Example 2 A low-melting polyester obtained by copolymerizing an acid component as a low-melting component by adding isophthalic acid in addition to terephthalic acid using a spunbond spinning machine of a sheath-core composite nozzle was used as a high-melting component. A sheath-core type composite spunbond fiber using polyethylene terephthalate has a fineness of 2
It was spun with dtex, and the fiber intersection was thermocompression-bonded with a hot embossing roll to produce a co-polyester / polyethylene terephthalate sheath-core spunbonded nonwoven fabric having a basis weight of 22 g / m ² and a thickness of 200 μm. It is slit to a width of 5 cm to form a band-shaped non-woven fabric. The same perforated tubular body as in Example 1 is used, and wound into a perforated tubular body under the same conditions as in Example 1 to form a cylindrical filter cartridge. did. The end face was welded with a hot plate having a surface temperature of 165 ° C. for 5 seconds to obtain a filter cartridge of the same type as FIG. This filter cartridge was more excellent in sealability than the filter cartridge of Example 1. This is presumably because the use of the sheath-core type conjugate fiber as the fiber improved the adhesiveness of the nonwoven fabric and increased the elasticity of the end face during sealing.

Example 3 A linear low-density polyethylene was used as the low melting point component, and polypropylene was used as the high melting point component. The fineness was ² dtex, the basis weight was 22 g / m ² , and the thickness was 20.
Using a 0 μm sheath-core composite spunbond nonwoven fabric, slitting it to a width of 5 cm to form a band-like nonwoven fabric, the same perforated tubular body as in Example 1 was used, and perforated under the same conditions as in Example 1. It was wound around a cylindrical body to form a cylindrical filter cartridge. The end face was welded with a hot plate having a surface temperature of 150 ° C. for 3 seconds to obtain a filter cartridge of the same type as that of FIG.
This filter cartridge was more excellent in sealability than the filter cartridges of Examples 1 and 2. This is presumably because the linear low-density polyethylene / polypropylene sheath-core composite spunbonded nonwoven fabric had excellent adhesiveness, so that the elasticity at the time of sealing the end face was higher.

(Example 4) A linear low-density polyethylene / polypropylene sheath-core composite short fiber having a fineness of 2 dtex, a cut length of 51 mm, and a number of crimps of 14 was produced using ordinary melt spinning. The short fiber is weighed 22 g / m ² with a card machine.
Was processed into a web, and the fiber intersection was thermocompression-bonded with a hot embossing roll to produce a 200 μm thick short fiber nonwoven fabric. Winding and end face welding were performed in the same manner as in Example 3 except that the nonwoven fabric was used, to obtain a filter cartridge of the same type as that of FIG. This filter showed some bubbling in the initial filtrate, and the maximum passage particle size was slightly larger than that of Example 3, but other than that, the filter had almost the same performance as that of Example 3.

Example 5 A filter cartridge was obtained in the same manner as in Example 3 except that the width of the band-shaped nonwoven fabric was 1 cm and the number of windings was 3.964. The filtration performance of this filter cartridge was almost the same as that of Example 3, but the winding time of the filter became longer.

Example 6 A filter cartridge was obtained in the same manner as in Example 3 except that the width of the band-shaped nonwoven fabric was 8 cm and the number of winds was 3.929. Although the maximum particle size of this filter cartridge was slightly larger than that of Example 3, the sealing property of the end face was good.

Example 7 A linear low-density polyethylene was used as the low melting point component and polypropylene was used as the high melting point component. The fineness was ² dtex, the basis weight was 22 g / m ² , and the thickness was 20.
Using a 0 μm sheath-core composite spunbond nonwoven fabric, slitting it to a width of 5 cm to form a band-like nonwoven fabric, the same perforated tubular body as in Example 1 was used, and perforated under the same conditions as in Example 1. It was wound around a cylindrical body to form a cylindrical filter cartridge. The same nonwoven fabric as the band-shaped nonwoven fabric (before slitting) was welded to the end face with a hot plate having a surface temperature of 150 ° C. for 3 seconds to obtain a filter cartridge of the same type as that of FIG. This filter cartridge had almost the same properties as in Example 3.

(Comparative Example 1) Short fibers of polypropylene having a fineness of 2 dtex, a cut length of 51 mm, and a number of crimps of 14 were prepared using ordinary melt spinning, and spun to obtain a spun yarn.
The spun yarn was wound around the same perforated cylindrical body as in Example 1 with a wind number of 3.098 to form a filter cartridge. The end face was welded with a hot plate having a surface temperature of 175 ° C. for 5 seconds to obtain a filter cartridge. This filter cartridge has many irregularities on the end face and lacks elasticity when sealing the end face. Therefore, the sealing performance of the end face was poor.

(Comparative Example 2) A linear low-density polyethylene / polypropylene sheath-core composite short fiber having a fineness of 2 dtex, a cut length of 51 mm, and a number of crimps of 14 was prepared using ordinary melt spinning, and then spun. Yarn was obtained. The spun yarn was wound around the same perforated cylindrical body as in Example 1 with a wind number of 3.098 to form a filter cartridge. The end face was welded with a hot plate having a surface temperature of 150 ° C. for 3 seconds to obtain a filter cartridge. Although this filter cartridge was superior to Comparative Example 1, it had many irregularities on the end face and lacked elasticity when sealing the end face. Therefore, the sealing performance of the end face was poor.

[0053]

[Table 1]

[0054]

As described in detail, the filter cartridge of the present invention is superior in the sealing property at the end as compared with the conventional thread-wound filter cartridge, and furthermore, has stable liquid permeability, filtration life and filtration accuracy. It is also excellent in properties and the like. Because the end face of the conventional thread-wound filter has a dense shape of spun yarn, if it is used as it is, of course, even if the end is heat-welded, the sealing performance is inferior. In the present invention, since the belt-shaped nonwoven fabric is used, such unique performance is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overview of a filter cartridge of the present invention.

FIG. 2 is an explanatory view showing an overview of a filter cartridge welded to the outer periphery of a side surface according to the present invention.

FIG. 3 is a partially cutaway perspective view of the filter cartridge shown in FIG.

FIG. 4 is a partially cutaway perspective view of the filter cartridge shown in FIG. 2;

FIG. 5 is an enlarged cross-sectional view of an end of the filter cartridge shown in FIG.

FIG. 6 is an enlarged sectional view of an end of the filter cartridge shown in FIG. 2;

FIG. 7 is an enlarged cross-sectional view of an end of a wound filter cartridge using a spun yarn.

FIG. 8 is an enlarged cross-sectional view of an end of a thread wound filter cartridge using a spun yarn whose end is welded.

FIG. 9 is an explanatory diagram showing a state in which a belt-shaped nonwoven fabric is wound by traversing.

FIG. 10 is a conceptual diagram of a spunbond nonwoven fabric.

FIG. 11 is a conceptual diagram of a short fiber nonwoven fabric.

FIG. 12 is an explanatory view showing a foreign matter collecting state by an emboss pattern of a long fiber nonwoven fabric.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Filter cartridge 2 Perforated cylindrical body 3 Converged band-shaped nonwoven fabric 4 End welded part 5 Thread spacing 6 Side outer peripheral welded part 7 Converged band-shaped nonwoven fabric adhered to end welded part 8 Spun yarn 9 Spun yarn was used Welding portion at end of thread-wound filter cartridge 10 Band-shaped nonwoven fabric 11 Bobbin 12 Traverse guide 13 Long fiber constituting spunbond nonwoven fabric 14 Particles 15 Short fiber constituting short fiber nonwoven fabric 16 Part with strong thermocompression bonding by emboss pattern 17 Emboss A portion with only weak thermocompression bonding due to deviation from the pattern 18 Foreign matter 19 A foreign material passing through a portion with only weak thermocompression bonding due to deviation from the emboss pattern

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 29/06 520D 520F

Claims (8)

[Claims] 1. A filter cartridge in which a band-shaped nonwoven fabric made of thermoplastic fiber is wound in a twill shape around a perforated tubular body, and end seal portions are provided at both ends of the filter cartridge. 2. The filter cartridge according to claim 1, wherein the end face sealing portion is formed by welding a band-shaped nonwoven fabric forming both end portions of the filter cartridge. 3. A sheet in which an end face sealing portion is formed on a surface of both end portions of a filter cartridge, the same resin as at least one of thermoplastic resins which are components of a thermoplastic fiber used for a strip-shaped nonwoven fabric forming the both end portions. The filter cartridge according to claim 1, wherein the filter cartridge is formed by sticking and welding. 4. The band-shaped nonwoven fabric has a width of 0.5 cm or more, and the product of the width (cm) and the basis weight (g / m ² ) of the band-shaped nonwoven fabric is 200 or less. Filter cartridge. 5. The thermo-adhesive conjugate fiber according to claim 1, wherein the thermoplastic fibers constituting the band-shaped nonwoven fabric are composed of a low-melting resin and a high-melting resin, and the difference between the melting points of both resins is 10 ° C. or more.
The filter cartridge according to any one of claims 4 to 4. 6. The filter cartridge according to claim 5, wherein the low melting point resin is linear low density polyethylene and the high melting point resin is polypropylene. 7. The filter cartridge according to claim 1, wherein the band-shaped nonwoven fabric is a long-fiber nonwoven fabric made by a spunbond method. 8. The porosity of the filter cartridge is 65.
The filter cartridge according to any one of claims 1 to 7, wherein the content of the filter cartridge is from 85% to 85%.