JP2001327817A - Filter cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter cartridge in which a shortage of filtration life and water permeability, which are problems of the conventional filter cartridge, are solved and the generation of materials loosened from the filter cartridge is prevented and which is small in aged deterioration of the filtration precision, long in filtration life and small in pressure loss. SOLUTION: This filter cartridge is obtained by winding a belt-shaped nonwoven fabric consisting of a thermoplastic fiber around a perforated cylindrical body in a twilled state and thermally bonding the belt-shaped nonwoven fabric on at least a part of points of contact or intersection points formed by winding the belt-shaped nonwoven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cylindrical filter cartridge for liquid filtration.

[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 into a twill shape around a perforated cylindrical core and then fluffing the spun yarn.Since it is easy and inexpensive to manufacture, it has been used for a long time. ing.

[0004] Such a conventional method of collecting foreign matter of a thread-wound filter cartridge involves collecting foreign matter with fluff generated from a spun yarn and entangling the foreign matter 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.

Several proposals have been made to solve the drawbacks of the wound filter cartridge using spun yarn. For example, JP-A-51-3
Japanese Patent No. 4469 discloses a method in which a fibrous sliver is used instead of a spun yarn, and the sliver is treated and cured with a thermosetting curing agent such as a urea resin. However, this method aims at improving the particle collecting performance and does not solve the above-mentioned problem.

Further, Japanese Utility Model Application Laid-Open No. 54-36878 discloses a method in which a cellulosic nonwoven fabric in the form of a tape is used instead of a spun yarn. According to the description of this publication, the advantage of this method is that there is no danger of elution of the binder, and the material cost and the production cost are low. However, this method does not solve the above-mentioned problem.

Further, Japanese Utility Model Publication No. 6-7767 discloses a filter material in which a porous tape-shaped paper is squeezed and squeezed while being twisted, and the diameter of which is regulated to about 3 mm. There has been proposed a filter cartridge in a form wound closely. In the case of this filter cartridge, there is a feature that the winding pitch of the winding can be increased as going outward from the porous inner cylinder.
However, it is necessary to squeeze and squeeze the filtration material, and therefore, the collection of foreign matter is mainly performed between the winding pitches of the filtration material. Therefore, the thread-wound type filter using a conventional spun yarn collects foreign matter with its fluff. As described above, it is difficult to expect foreign matter collection by the filtration material itself. As a result, the filter may be clogged on the surface and the filtration life may be shortened, or the liquid permeability may be poor.

A similar invention is disclosed in Japanese Patent Publication No. 1-256.
No. 07, Japanese Utility Model Publication No. 3-52090,
Although these are disclosed in Japanese Patent No. 317513, they are intended to improve water absorption, oil absorption, antibacterial properties, etc., and do not solve the above-mentioned problems.

[0009] In addition, Japanese Patent Application Laid-Open No. 1-145423 discloses that a cellulose spunbond nonwoven fabric is cut into a band-like body through a bobbin having a large number of fine holes, passed through a narrow hole, and twisted to form a string. A wound filter has been proposed. By using this method, it is possible to make a filter that has higher mechanical strength and does not dissolve in water or elute binders, compared to a conventional roll tissue filter made by converting α-cellulose from purified softwood pulp into thin paper and winding it into a roll. Is thought to be possible. However, the cellulose spunbond non-woven fabric used in this filter is in the form of paper, so it has too much rigidity and easily swells in liquid, and the swelling causes a decrease in filter strength, a change in filtration accuracy, and liquid permeability. There is a possibility that various problems such as deterioration of filtration and reduction of filtration life may occur. In addition, the bonding of fiber intersections is often performed by chemical treatment or the like, but the bonding is often insufficient, causing a change in filtration accuracy or a drop of fiber waste. In many cases, it is difficult to obtain stable filtration performance.

[0010] Japanese Patent Application Laid-Open No. 4-45810 discloses that
A slit nonwoven fabric made of a composite fiber 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 tube so that the fiber density becomes 0.18 to 0.30 g / cm ^3. Filters have been proposed. This filter 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 split the conjugate fiber, and it is difficult to uniformly split the entire nonwoven fabric by high-pressure water processing. In addition, since the strength of the nonwoven fabric may be reduced due to uneven division, the strength of the manufactured filter is reduced and it is easy to deform during use, or the porosity of the filter changes and the liquid permeability decreases there's a possibility that. A similar patent is disclosed in
-45811, Japanese Utility Model Laid-Open No. 4-131412,
Japanese Utility Model Laid-Open No. 4-131413, Japanese Utility Model Laid-Open No. 5-2715, and Japanese Utility Model Laid-Open No. 5-18614 all use split fibers and do not solve the above-mentioned problems.

On the other hand, several proposals have been proposed for improving the pressure resistance of a filter cartridge made of thermoplastic fibers. For example, Japanese Patent Publication No. Sho 56-43139 proposes a hollow cylindrical filter cartridge in which a fiber assembly layer containing a heat-fusible conjugate fiber is wound around a core while being heated. This method is excellent as a method for improving the pressure resistance of the filter cartridge, but due to its production method, the surfactant applied to the fiber surface may be mixed into the filtrate and the filtrate may foam.

Japanese Patent Publication No. 7-98131 discloses that
There has been proposed a tubular filter cartridge formed of ultrafine conjugate fibers obtained by a melt blowing method. This filter cartridge has excellent performance with no bubbles in the filtrate. However, the fiber produced by the melt blow method cannot be produced at a very high speed, and requires advanced technology to make the nonwoven fabric with uniform quality.
Often expensive. Further, Japanese Unexamined Patent Publication No. Hei.
Japanese Patent Application Publication No. JP-A-2005-26464 proposes a tubular filter cartridge in which a composite spunbond filament is wound and heat-sealed.
Spunbond filaments are excellent in productivity, but it is difficult to make the nonwoven fabric with uniform quality, so the performance of the filter cartridge will be uneven or use advanced technology to prevent it. In some cases, the filter cartridge becomes expensive.

Japanese Patent Publication No. 11-504853 discloses that a high-temperature fiber from a melt-blowing die which is maintained in a sufficiently molten state is collected on a collection / transport roller, and the fiber is collected. In a state of being kept in a softened state or a molten state, by adhering to a melt-blown fiber mass discharged from another melt-blowing die and winding it up to be in a uniformly mixed state, a filter that can withstand pressure can be manufactured. And However, this method is also unsatisfactory in terms of changes in filtration accuracy with time, filtration life, and pressure loss.

Further, in US Pat. No. 6,054,216, a melt-blown nonwoven fabric having a width of 2.5 to 16 cm and a fiber diameter of 0.5 to 10 μm is twisted and wound around a reinforcing cord to form a cord. Discloses a method of manufacturing a filter cartridge in which a filter cartridge is wound in a twill pattern. In this method, the melt-blown non-woven fabric is simply twisted to the reinforcing cord, so when the flow rate of the liquid to be filtered is high, the reinforcing cord and the melt-blown non-woven fabric may be separated, or the twist of the melt-blown non-woven fabric may loosen and the filtration accuracy may change. Therefore, it is considered difficult to maintain a constant filtration ability.

[0015]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the conventional filter cartridges, that is, the deficiency of filtration life and water permeability, and the prevention of falling off from the filter. It is an object of the present invention to provide a filter cartridge having little change, a long filtration life, and a small pressure loss.

[0016]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that when manufacturing a filter cartridge in which a band-shaped nonwoven fabric containing thermoplastic fibers is wound in a twill shape so as to form a cylindrical shape, furthermore, The inventors have found that the above-mentioned problems can be solved by thermally bonding the wound belt-shaped nonwoven fabrics to each other, and have reached the present invention.

The present invention has the following configuration. (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, wherein at least a part of the contact points or intersections between the wound band-shaped nonwoven fabrics is thermally bonded. A filter cartridge comprising:

(2) The filter cartridge according to the above (1), wherein the fibers constituting the band-shaped nonwoven fabric are composite fibers composed of a low-melting resin having a melting point difference of 10 ° C. or more and a high-melting resin.

(3) The filter cartridge according to the above (1) or (2), wherein the belt-shaped nonwoven fabric is a long-fiber nonwoven fabric in which at least a part of fiber intersections is thermally bonded.

(4) The filter cartridge according to any one of the above (1) to (3), wherein the band-shaped nonwoven fabric is a spunbonded nonwoven fabric.

(5) The filter cartridge according to the above (1) or (2), wherein the belt-shaped nonwoven fabric is a meltblown nonwoven fabric.

(6) The above-mentioned items (1) to (3), wherein the belt-shaped nonwoven fabric is a nonwoven fabric obtained by laminating at least two layers of a long-fiber nonwoven fabric having at least a part of the fiber intersection points thermally bonded and a melt-blown nonwoven fabric. The filter cartridge according to any one of the above.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. The filter cartridge of the present invention is a filter cartridge obtained by winding a belt-shaped nonwoven fabric made of thermoplastic fiber around a perforated tubular body in a twill shape. The band-shaped nonwoven fabric referred to in the present invention is a narrow nonwoven fabric, and is a nonwoven fabric obtained by slitting (cutting) a wide nonwoven fabric, or a nonwoven 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.

In the present invention, the thermoplastic fiber refers to a fiber made of a thermoplastic resin. As the thermoplastic fiber used in the present invention, any thermoplastic resin that can be melt-spun can be used. Examples of the thermoplastic resin, polypropylene, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, copolymerized polypropylene copolymer (for example, mainly propylene,
A polyolefin-based resin such as a binary or multi-component copolymer with ethylene, butene-1,4-methylpentene-1 or the like;
Polyester terephthalate, polybutylene terephthalate, polyester resins such as low-melting polyesters obtained by copolymerizing acid components with addition of isophthalic acid in addition to terephthalic acid, polyamide resins such as nylon 6, nylon 66, polystyrene (atactic polystyrene) ,
Thermoplastic resins such as syndiotactic polystyrene), polyurethane elastomers, polyester elastomers, and polytetrafluoroethylene.

It is also possible to use a functional resin such as a filter cartridge having biodegradability by using a biodegradable resin such as a lactic acid-based polyester. Furthermore,
When using a resin that can be polymerized with a metallocene catalyst such as a polyolefin resin or polystyrene, if a resin polymerized with a metallocene catalyst is used, the properties of the metallocene resin, such as improved nonwoven fabric strength, improved chemical resistance, and reduced production energy, can be improved. It is preferable because it is utilized in a filter cartridge. These resins may be blended and used to adjust the thermal adhesiveness and rigidity of the nonwoven fabric. Among them, polyolefin resins such as polypropylene are preferable from the viewpoint of chemical resistance and price when the filter cartridge is used for filtration of water or aqueous solution at room temperature, and when used for relatively high temperature liquid. Polyester-based resins, polyamide-based resins, syndiotactic polystyrene and the like are preferred.

In the present invention, the band-shaped nonwoven fabric is formed by mixing a hydrophilic resin such as polyvinyl alcohol with the thermoplastic resin as a raw material of the thermoplastic fiber forming the band-shaped nonwoven fabric, or by subjecting the surface of the band-shaped nonwoven fabric to plasma processing. Hydrophilization improves the liquid permeability when used for aqueous liquids. Therefore, when filtering an aqueous solution, a filter cartridge using such a resin is preferable.

In the present invention, the bonding method of the fiber intersections for forming the nonwoven fabric from the thermoplastic fibers is not particularly limited, but it is preferable to use a thermal bonding method. As a method of thermal bonding of the fiber intersection of the thermoplastic fibers used in the present invention,
Examples include a method of thermocompression bonding using a device such as a hot embossing roll and a hot flat calender roll, and a method of using a heat treatment machine such as a hot air circulation type, a heat through air type, an infrared heater type, and a vertical hot air jet type. it can. Above all, the method using a hot embossing roll is preferable because the production speed of the nonwoven fabric can be improved and the productivity is good, so that the cost of the nonwoven fabric can be reduced.

Further, the nonwoven fabric made by the method using the hot embossing roll has a portion having strong thermocompression bonding by an emboss pattern and a portion having only weak thermocompression bonding by deviating from the emboss pattern. As a result, the obtained filter cartridge can collect a large amount of foreign matter in a portion where strong thermocompression bonding is performed. on the other hand,
Part of the foreign matter is collected in the part with only weak thermocompression bonding, but the remaining foreign matter can pass through the nonwoven fabric and move to the next layer, so it has a deep filtration structure that uses the inside of the filter medium preferable. In this case, it is desirable that the area of the emboss pattern is 5 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 nonwoven fabric to some extent, and to catch the foreign matter that has passed inside the filter cartridge, thereby extending the life of the filter cartridge.

The thermoplastic fibers constituting the belt-shaped nonwoven fabric used in the present invention have a melting point difference of 10 among the thermoplastic fibers.
It is more preferable to use a composite fiber composed of a low melting point resin and a high melting point resin having a temperature of at least 15 ° C., preferably at least 15 ° C., because the thermal adhesion of the band-shaped nonwoven fabric 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 made of a low-melting resin and a high-melting resin is used as the fiber constituting the band-shaped nonwoven fabric, the degree of fiber adhesion can be easily adjusted. Alternatively, two types of thermoplastic fibers may be formed by using 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, and the resulting fibers may be mixed into a nonwoven fabric.

The combination of the low melting point resin and the high melting point resin of the composite 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 / polyester, polypropylene / polyester, low melting polyester / high melting polyester, various polyethylene / nylon 6, polypropylene / nylon 6, nylon 6 / nylon 66, nylon 6 / polyester, etc. Can be mentioned. In particular, when a combination of linear low-density polyethylene / polypropylene, a combination of high-density polyethylene / polypropylene, or a combination of high-density polyethylene / polyethylene terephthalate is used, the rigidity and porosity of the nonwoven fabric and the end of the filter cartridge can be easily adjusted. Preferred. When the obtained filter cartridge is used for filtering a relatively high-temperature liquid, 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 composite form of the composite fiber is not particularly limited, and any shape such as a sheath-core type, a side-by-side type, and a sea-island type can be used. preferable.

In the present invention, the belt-shaped nonwoven fabric may contain fibers other than thermoplastic fibers as long as the object of the present invention is not impaired. Examples of fibers other than the thermoplastic fibers include rayon, cupra, cotton, hemp, pulp, and carbon fibers.

In the present invention, the perforated tubular body serves as a core material of the filter cartridge, and its material and shape must be strong enough to withstand the external pressure during filtration and the pressure loss must be extremely high. If it is not particularly limited, for example, it may be 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, or ceramic or stainless steel. Similarly processed ones are acceptable. 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.

A method for winding a band-shaped nonwoven fabric around a perforated tubular body and then thermally bonding at least a part of a contact point or an intersection between the wound band-shaped nonwoven fabrics will be described below. FIG. 2 shows an example of the manufacturing apparatus. The device is provided with a traverse guide 4. The traverse guide 4
The traverse cam 5 is reciprocated in the AA 'direction by the rotational movement of the traverse cam 5 driven by the motor. On the other hand, the hoisting arm 6 is connected to the traverse cam 5 by a gear, and moves in the direction B around the shaft 7 as a fulcrum by the rotational movement of the traverse cam 5. A bobbin 8 is provided on the winding arm 6.
Is provided. The perforated tubular body 2 is attached to the bobbin 8. The bobbin 8 is also connected to the traverse cam 5 by a gear, and rotates in the direction C. The number of winds is
This is the number of rotations of the bobbin 8 while the traverse guide 4 moves from the position of one end S to the position of the other end E of the perforated tubular body 2.

After passing through a complicated thread path, the belt-shaped nonwoven fabric 9 is wound around the perforated tubular body 2 by the rotating force of the bobbin 8. The thread path will be described. The belt-shaped nonwoven fabric 9 is supplied in a flat state, and is converged by the converging guide 10.
After that, it is sent to the tension guide 11. The tension guide 11 includes about 1 to 7 tension guides, and two plates are attached to each tension guide 11. The two plates of the tension guide 11 sandwich the band-shaped nonwoven fabric converged at a certain pressure by compressed air to apply tension to the band-shaped nonwoven fabric. Subsequently, the band-shaped nonwoven fabric is sent to the fulcrum guide 12 and further sent to the traverse guide 4. The band-shaped nonwoven fabric is reciprocated in the AA ′ direction of the traverse guide 4,
The bobbin 8 is wound in a twill shape by the rotational movement in the C direction. Then, the band-shaped nonwoven fabric is heated by an air heater 13 located symmetrically with the traverse guide 4 and the bobbin 8 interposed therebetween, and is thermally bonded to the wound filter cartridge 1.

Note that, instead of the air heater 13, a far-infrared heater, a contact heater or the like can be used. However, in the present invention, since the belt-shaped nonwoven fabric is wound around the perforated tubular body at a relatively high speed, an air heater that heats quickly and has less temperature unevenness is preferable. The heating conditions vary depending on the heating method, the material used, the winding speed, and the like. However, when using an air heater, the wind speed is about 5 to 10 m / sec, and the melting point of the thermoplastic fiber (for a composite fiber, the low melting point resin is used). (Melting point) is about 10 to 20 ° C. higher. If the heating is too weak, the adhesion will be insufficient, and if the heating is too strong, the fibers will deteriorate or, in some cases, the band-shaped nonwoven fabric will be cut.

By the above-mentioned bonding, at least a part of the contact points or intersections between the band-shaped nonwoven fabrics constituting the filter cartridge is firmly bonded. By adjusting the heating conditions, not only the contacts or intersections of the strip-shaped nonwoven fabrics can be bonded, but also the contacts or intersections of the thermoplastic fibers constituting the strip-shaped nonwoven fabric can be bonded. When the thermoplastic fibers are strongly adhered to each other, it is possible to prevent the filter medium from falling off and the filter cartridge from being deformed.

Since the filter cartridge of the present invention is formed by winding a band-shaped nonwoven fabric in a twill shape, unlike the filter in which the nonwoven fabric is wound around a perforated cylindrical body like a roll paper, the filter cartridge reaches from the surface of the filter medium to the deep part of the filter medium. A hole is open. In the case of a wound filter made from a conventional spun yarn, the position of the fiber constituting the filter cartridge changes easily due to the passage of liquid.Therefore, if this hole is present, particles will be generated on the filtrate side when the pressure for filtration increases. It has the disadvantage of spilling.

However, in the case of the filter cartridge of the present invention, since the band-shaped nonwoven fabric is used instead of the spun yarn, the position of the fiber is difficult to move, and when the pressure for filtration increases, particles flow out to the filtrate side. Very little to do. Furthermore, in the case of the present invention, since the belt-shaped nonwoven fabrics are bonded to each other, such outflow of particles to the filtrate is almost eliminated. Therefore, the holes reaching from the surface of the filter medium to the deep part of the filter medium are not disadvantageous but rather function to assist the deep filtration structure of the filter cartridge. Conversely, a filter in which a non-woven fabric is wound around a perforated cylindrical body like a roll paper does not have such holes, so that the particle size distribution of the particles contained in the liquid to be filtered does not match the filtration accuracy of the filter cartridge. In some cases, the surface of the filter cartridge may be blocked, and almost no liquid flow may occur. In other words, the present invention uses the band-shaped nonwoven fabric and firmly adheres the constituent fibers, so that the pores reaching from the surface of the filter medium to the deep part of the filter medium can be effectively utilized without defects.

The condition for winding the band-shaped nonwoven fabric around the perforated cylindrical body is, for example, that the initial speed of the bobbin is 200 to 2000 rpm.
m and wind while applying appropriate tension. The tension at this time depends on the type of the band-shaped nonwoven fabric and the heating conditions,
About 5N is appropriate.

After being wound around the perforated tubular body, the bobbin may be cooled in order to remove residual heat of the heated band-shaped nonwoven fabric. Examples of the cooling method include a cold air blowing method and a contact method, but a contact cooling method is preferable in order to prevent an influence on a heater during winding. If the heating is too strong in order to strengthen the adhesion between the band-shaped nonwoven fabrics, if the cooling is insufficient, the band-shaped nonwoven fabric will overheat and the constituent fibers will be damaged, or the band-shaped nonwoven fabric will be wound by the winder device itself or the yarn. May fuse to road guides. On the other hand, if the cooling is too strong, the wound band-shaped nonwoven fabric may have insufficient adhesion.

Heating for bonding the band-shaped nonwoven fabrics to each other is not necessarily performed at the time of winding, and may be performed, for example, after winding around a perforated cylindrical body to form a filter cartridge. As the heating device in that case, for example, a far-infrared heating device, a hot air circulation heating device, or the like can be used. In this case, care must be taken to prevent unevenness in adhesion between the inner layer and the outer layer of the filter cartridge.

When the heating is performed, the degree of heating is adjusted from the upstream side to the downstream side of the filter cartridge (for example, from the outside to the inside of the filter cartridge when the filtrate flows from the outside to the inside of the filter cartridge), and the degree of heating is adjusted. May be graded. For example, if the adhesive on the upstream side is weakened and the adhesive on the downstream side is strengthened, an excellent filter cartridge can be obtained in which surface clogging is less likely to occur and particles do not drop off to the filtrate side.

The filtration accuracy of the filter cartridge 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. Since the winding number when winding the band-shaped nonwoven fabric 9 around the perforated tubular body 2 needs to be extremely accurate, the movement amount of the traverse guide and the rotation speed of the bobbin are linked by a gear or the like, and this value is determined. You need to be careful not to get out of order. Then, the band-shaped nonwoven fabric is wound to an outer diameter of about 1.5 to 3 times the outer diameter of the perforated tubular body 2 to form a filter cartridge.

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 to 40 cm. If the width is less 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. If a filter cartridge having the same porosity is made, the winding time is long. And productivity decreases. If the width exceeds 40 cm, the friction on the yarn path of the winder such as the traverse guide increases, or the size of the converged nonwoven fabric tends to be uneven.

The basis weight of the band-shaped nonwoven fabric, that is, the weight per unit area of the nonwoven fabric is preferably from 5 to 200 g / m ² .
If this value is less than 5 g / m ² , the amount of fibers is reduced, so that unevenness of the nonwoven fabric is increased, the strength of the nonwoven fabric is reduced, or thermal bonding at fiber intersections may be difficult. On the other hand, if this value exceeds 200 g / m ² , the rigidity of the belt-shaped nonwoven fabric becomes too large, and it is difficult to wind the nonwoven fabric around the perforated tubular body in a twill shape.

The upper limit of the width of the band-shaped nonwoven fabric varies depending on the basis weight, and the value of width (cm) × basis (g / m ² ) of the band-shaped nonwoven fabric is preferably 200 cm · g / m ² or less.
When this value exceeds 200 cm · g / m ² , 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 when it is bundled, it becomes too thick, so that it is densely wound. It becomes difficult.

As the band-shaped nonwoven fabric, a long-fiber nonwoven fabric, a melt-blown nonwoven fabric, or a laminated nonwoven fabric thereof, in which at least a part of the fiber intersections are thermally bonded, are preferable.
Among them, the long fiber nonwoven fabric is preferable. As the long-fiber nonwoven fabric, a nonwoven fabric obtained by a spunbond method is particularly preferable.

The spunbond 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. As shown in FIG. 3, the long-fiber nonwoven fabric made of a thermoplastic resin obtained by the spunbonding method has the fiber direction aligned with the machine direction, so that the holes formed by the fibers 15 are elongated, and the maximum size of the passing particles 14 is large. The diameter becomes smaller. In the case of the present invention, since the fiber intersection 16 and the intersection of the band-shaped nonwoven fabric are firmly adhered by heating at the time of winding the filter cartridge,
The effect becomes more remarkable.

On the other hand, in the case of the short-fiber nonwoven fabric obtained by the card method or the like, since the fiber direction is not constant as shown in FIG. 4, the holes formed by the fibers 17 have a shape close to a circle or a square. Even though the fiber diameter and the porosity are the same as those of the long-fiber nonwoven fabric made by the spun bond method or the like, the maximum diameter of the passing particles 14 increases. Since the water permeability of the filter medium is substantially determined by the porosity if the fiber diameter is the same, a filter cartridge having excellent water permeability can be obtained by using a long-fiber nonwoven fabric made by a spun bond method or the like.

Since the above effects are reduced when a binder such as an adhesive which closes the pores of the filter medium is used, the use of a cellulose spunbond nonwoven fabric is not preferred. 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.

In the filter cartridge of the present invention, when the band-shaped nonwoven fabric is heated as described above, the heat-bonded fiber intersections may occur. However, the band-shaped nonwoven fabric may be the long-fiber nonwoven fabric, the melt-blown nonwoven fabric, or any of these. In the case of a laminated nonwoven fabric, it has a fiber intersection where the band-shaped nonwoven fabric has already been thermally bonded. Since the positions of the fibers constituting the filter medium are fixed by the fiber intersections, the pores of the nonwoven fabric made of the fibers hardly have openings even when the filtration pressure applied to the filter cartridge increases. Further, the fibers are hardly dropped or the filter cartridge is hardly deformed.

Further, since the band-shaped nonwoven fabrics or the constituent fibers are thermally bonded to each other, the filter cartridge of the present invention has excellent solvent resistance. For example, a filter cartridge made of conventional polypropylene spun yarn without thermal bonding may cause swelling of the filter cartridge when used in an organic solvent such as xylene for a long time, resulting in a change in filtration accuracy or a decrease in pressure resistance. is there. On the other hand, for example, the filter cartridge of the present invention using a high-density polyethylene / polypropylene spunbonded nonwoven fabric as a band-shaped nonwoven fabric and thermally bonding the contact points or intersections between the band-shaped nonwoven fabrics can be used for a long time with an organic solvent such as xylene. Become.

The average fiber diameter of the long fibers used in the long-fiber nonwoven fabric varies depending on the use of the filter cartridge and the type of the resin, and thus cannot be unconditionally specified.
80 μm is desirable. When the average fiber diameter exceeds 680 μm, 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 average fiber diameter to 9 μm or more, sufficient strength of the nonwoven fabric can be obtained, and the strength of the manufactured filter cartridge increases, which is preferable. In addition, when spinning a fiber having an average fiber diameter of less than 9 μm by the current spunbond method, the workability and spinnability of the nozzle used are deteriorated, and as a result, the price of the manufactured spunbond nonwoven fabric increases. Sometimes.

The constituent fibers of the long-fiber nonwoven fabric do not necessarily have to have a circular cross-section, and a yarn having a modified 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. As a method for bonding the fiber intersections of the long-fiber nonwoven fabric, the above-mentioned heat bonding method is suitably used, and among them, a method using a hot embossing roll is preferable.

When the band-shaped non-woven fabric is a melt-blown non-woven fabric, the melt-blown non-woven fabric has a finer size than the long-fiber non-woven fabric and can easily form a uniform formation. can do. The average fiber diameter of the fibers of the melt-blown nonwoven fabric varies depending on the use of the filter cartridge and the type of the resin, but is desirably 0.5 to 1000 μm, preferably 1 to 50 μm. When the average fiber diameter is less than 0.5 μm, it is difficult to produce a nonwoven fabric, and the cost of the obtained filter cartridge may increase. When the average fiber diameter exceeds 1000 μm, the distribution of the fiber diameter can be broadened to form a nonwoven fabric. Gets worse. In addition, the average fiber diameter is 50
If it exceeds μm, adjacent fibers may adhere to each other due to residual heat, but there is no particular problem as long as the effect of the present invention is not impaired.

Further, as the band-shaped nonwoven fabric, a nonwoven fabric obtained by laminating at least two layers of the long-fiber nonwoven fabric and the melt-blown nonwoven fabric may be used. In this case, the advantages of the long-fiber nonwoven fabric and the melt-blown nonwoven fabric can be used together. Since the particle collection performance of the nonwoven fabric is greatly affected by the fiber diameter of the meltblown nonwoven fabric, it is particularly preferable when the filter cartridge has high accuracy.

The porosity of the filter medium of the filter cartridge of the present invention 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 8
If it is larger than 5%, 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.

In the present invention, it is more preferable that the end face of the filter cartridge is smoothed by heat bonding or the like. After the band-shaped nonwoven fabric forming both end portions of the filter cartridge is melted by heat, a solvent, ultrasonic waves, or the like, it is smoothed by solidifying while shaping it into a smooth end face. In the present invention, since a belt-shaped nonwoven fabric made of thermoplastic fibers is used, a method using heat is preferable. When this processing is performed, a smooth end face seal portion is formed at both end portions of the filter cartridge, so that the sealing property is improved, which is preferable.

[0059]

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 and Number of Winders) An apparatus as shown in FIG. 2 was used. The traverse width (between SE in FIG. 2) is 2
The diameter of the hole of the traverse guide (4 in FIG. 2) was set to 5 mm. The initial speed of the bobbin was set to 400 rpm, and the tension of the nonwoven fabric was set to 1.5N. Also, the number of winds,
That is, the number of times the band-shaped nonwoven fabric was wound from one end to the other end of the perforated tubular body was adjusted by interlocking the reciprocating motion of the traverse guide and the rotating motion of the perforated tubular body with several gears having an appropriate number of teeth. .

(Density and thickness of non-woven fabric) A non-woven fabric was cut from the non-woven fabric to be evaluated so as to have an area of 500 cm ^2, and its weight was measured to determine the weight (g) per 1 m ^2.
And converted to the basis weight. In addition, the thickness of the cut nonwoven fabric was arbitrarily measured at 12 points, and the average value of 10 points excluding the maximum value and the minimum value of the 12 points was defined as the thickness of the nonwoven fabric.
The thickness of each point was measured using a “Digisic Nestester (trade name)” manufactured by Toyo Seiki Seisaku-sho, and a load of 19
The measurement was performed under the conditions of 6 Pa and a measurement speed of 2 mm / sec.

(Average Fiber Diameter of Nonwoven Fabric) Five places were randomly sampled from the nonwoven fabric to be evaluated, photographed with a scanning electron microscope, and 20 fibers were randomly selected for each place. Was measured, and the average value was defined as the average fiber diameter (μm) of the nonwoven fabric.

(Porosity of Filter Media in 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 (the part where the perforated tubular body has been removed from the filter cartridge), the outer diameter of the perforated tubular body is used for the inner diameter value, and the weight value of the filter cartridge is used for the weight value. The value obtained by subtracting the weight of the perforated cylindrical body from the weight was used. (Apparent volume of filter medium) = π ｛(outer diameter of filter medium) ² − (inner diameter of filter medium) ² ｝ × (length of filter medium) / 4 (true volume of filter medium) = (weight of filter medium) / (raw material of filter medium) (Porosity of filter medium) = {1- (true volume of filter medium) / apparent volume of filter medium) × 100%

(Initial collection particle size, initial pressure loss, 0.2M
Particle size collected at Pa, amount collected at 0.2 MPa, 0.2 MPa
Shrinkage) One filter cartridge is attached to the housing (transparent) of the circulating filtration performance tester, and the flow rate is adjusted to ³⁰ dm ³ per minute by a pump to circulate water. The pressure loss before and after the housing at this time was defined as the initial pressure loss. The appearance of the filter cartridge at this time was photographed. Next, in the circulating water, seven types of test powder I (abbreviated as JIS type 7) specified in JIS Z 8901. Median diameter: 27
) Was continuously added at a rate of 0.2 g / min per minute. After 5 minutes from the start of the addition, the stock solution and the initial filtrate were collected, diluted with an appropriate magnification, and the number of particles contained in each solution was measured using a light-blocking method. The initial collection efficiency was calculated by measuring using a particle detector. Further, by interpolating the value, a particle size showing a collection efficiency of 80% was obtained, and was set as an initial collection particle size. Continue JIS7
Seed added, pressure loss before and after housing is 0.2MPa
At which point the undiluted solution and the filtrate at 0.2 MPa were collected,
Similarly, the collection efficiency and the collection particle size were calculated.
The trapping efficiency at the time of MPa and the trapped particle size at the time of 0.2 MPa were defined. The cake addition amount at the time when the pressure loss became 0.2 MPa was defined as the trapping amount. Further, seven kinds of JIS were continuously added, and the appearance of the filter cartridge when the pressure loss before and after the housing became 0.5 MPa was photographed under the same conditions (shooting distance, magnification, etc.) as before. Then, the outer diameter of the filter cartridge shown in the two photographs is measured by image analysis. It was judged as x.

(Dropping of Filter Media and Foaming of Initial Filtrate) One filter cartridge was attached to the housing (transparent) of the circulating filtration performance tester, and the flow rate was 3 min / min by a pump.
Adjust to 0 dm ³ and pass water, initial stage (from the beginning of liquid flow)
1 dm ³ of the filtrate is collected. The filtrate 0.1 dm ³ was filtered through a black nitrocellulose membrane filter paper with a pore size of 0.8 μm, 5 mm square, and observed under a microscope, and five filter medium constituent fibers were arbitrarily selected from the filter paper in a 5 mm square area. The above cases were evaluated as x, the cases of 1 to 4 were evaluated as Δ, and the cases of less than 1 were evaluated as 個 (average of n = 2). Further, 0.05 dm ³ of the filtrate was placed in a colorimetric bottle having a capacity of 0.1 dm ³ and vigorously stirred, and 10 seconds after the stirring was stopped, 5 or more bubbles having a diameter of 1 mm or more were observed. ~ 4
The case where the number was found was evaluated as △, and the case where less than 1 was found was evaluated as ○ (average of n = 2).

(Swelling Test with Organic Solvent) A filter cartridge to be tested with ethyl acetate is placed in a closed container having a volume of ³ dm ³ , and ethyl acetate is immersed in the filter cartridge. Reflux the sealed container at 50 ° C for 24 hours.
Heat for hours. Immediately after stopping the heating, the filter cartridge is taken out, and the outer diameter of the swollen filter cartridge is measured and compared with the original outer diameter. The swelling ratio is calculated as (swelling ratio) = {(outer diameter after swelling) − (original outer diameter)} /
(Original outer diameter) × 100%, and the swelling ratio was evaluated as ○ when it was less than 5%, Δ when it was 5% or more and less than 10%, and X when it was 10% or more. A similar test was performed with xylene instead of ethyl acetate.

Example 1 As a nonwoven fabric, a basis weight of 22 g / m ² and a thickness of 200 μm obtained by a spun bond method were used.
m, average fiber diameter is 17 μm, and the fiber intersection is thermo-compressed with a hot embossing roll (melting point: 165 ° C.)
A long fiber nonwoven fabric was used. Width 50
mm to form a band-shaped nonwoven fabric. In addition, as a perforated cylindrical body, the inner diameter is 30 mm, the outer diameter is 34 mm, and the length is 250 m.
m, and a polypropylene injection-molded product having 180 holes of 6 mm square was used. Using the apparatus shown in FIG. 2, the hot air flowing out of the air heater 13 is changed to 15 Nm ³ /
min, set to 180 ° C. And the band-shaped nonwoven fabric,
The filter cartridge as shown in FIG. 1 was obtained by winding around a perforated cylindrical body with a winding number of 3.2917 to an outer diameter of 60 mm. The evaluation results are shown in Table 1. The resulting filter cartridge has no bubbling or filter media
In addition, the pressure loss was small, and there was almost no change in the collected particle size when the pressure was increased.

Example 2 As a nonwoven fabric, a basis weight of 22 g / m ² and a thickness of 200 μm obtained by a spun bond method were used.
m, average fiber diameter 17 μm, and high-density polyethylene (melting point 13
5 ° C.) / Polypropylene (melting point: 165 ° C.) long-fiber nonwoven fabric of sheath-core type composite fiber was used. The long fiber nonwoven fabric was slit into a width of 50 mm to obtain a belt-shaped nonwoven fabric. In addition, as a perforated cylindrical body, the inner diameter is 30 mm, the outer diameter is 34 mm, and the length is 2.
An injection molded product made of polypropylene and having a diameter of 50 mm and having 180 holes of 6 mm square was used. Then, using the apparatus shown in FIG. 2, the hot air flowing out of the air heater 13 was set to 15 Nm ³ / min and 140 ° C. Then, the belt-shaped nonwoven fabric was wound around a perforated tubular body with a winding number of 3.2917 to an outer diameter of 60 mm to obtain a filter cartridge as shown in FIG. The evaluation results are shown in Table 1. In the obtained filter cartridge, the pressure loss was smaller than that in Example 1 and almost no change in the trapped particle size when the pressure was increased.

Example 3 A nonwoven fabric having a basis weight of 22 g /
A melt-blown nonwoven fabric of a sheath-core composite fiber made of propylene / ethylene / butene-1 random copolymer (melting point 135 ° C.) / polypropylene (melting point 165 ° C.) having a m ² , a thickness of 200 μm and an average fiber diameter of 2 μm was used. . The melt-blown nonwoven fabric was slit into a width of 50 mm to obtain a belt-shaped nonwoven fabric. The perforated cylindrical body has an inner diameter of 30 mm, an outer diameter of 34 mm, a length of 250 mm, and a hole of 6 mm square has 18 holes.
An injection-molded product made of polypropylene, which was opened 0 times, was used. Then, using the device shown in FIG.
The hot air coming out of No. ³ was set at 15 Nm ³ / min and 140 ° C. Then, the belt-shaped nonwoven fabric was wound around a perforated tubular body with a winding number of 3.2917 to an outer diameter of 60 mm to obtain a filter cartridge as shown in FIG. The evaluation results are shown in Table 1. The obtained filter cartridge had a smaller initial collection particle size than that of Example 2.

Example 4 A spunbond long-fiber nonwoven fabric having a basis weight of 12 g / m ² and an average fiber diameter of 17 μm was prepared.
High-density polyethylene (melting point 135 ° C) / polypropylene (melting point 1)
65 ° C.) was used. In addition, as a melt blown nonwoven fabric, the basis weight is 10 g.
/ M ² , polypropylene having an average fiber diameter of 2 μm (melting point 16
5 ° C.) was used. Then, three spun-bonded long-fiber nonwoven fabrics / melt-blown non-woven fabric / spun-bonded long-fiber nonwoven fabric were laminated and thermocompression-bonded with a hot emboss roll to obtain an SMS (spun-bond / melt-blow / spun-bond) non-woven fabric. The SMS non-woven fabric is 50m wide
m to form a band-shaped nonwoven fabric. In addition, as a perforated cylindrical body, inner diameter 30 mm, outer diameter 34 mm, length 250 mm
And an injection-molded product made of polypropylene having 180 holes of 6 mm square was used. Then, using the device shown in FIG.
³ / min, 140 ° C. Then, the band-shaped nonwoven fabric is formed into a perforated cylindrical body with a winding number of 3.2917 and an outer diameter of 60 m.
m to obtain a filter cartridge as shown in FIG. The evaluation results are shown in Table 1. The obtained filter cartridge had a small initial pressure loss and a large trapping amount as compared with Example 3.

Comparative Example 1 Short polypropylene fibers having an average fiber diameter of 17 μm, a cut length of 51 mm, and a number of crimps of 14 were prepared by a usual melt spinning method, and spun to produce a 2 m diameter.
m was obtained. The spun yarn has a winding number of 3.29.
At 17, a filter cartridge was formed by winding it up in the same perforated cylindrical body as in Example 1. Surface temperature of both ends
It was heated for 5 seconds on a hot plate at 75 ° C. and welded to form a filter cartridge. The evaluation results are shown in Table 1. This filter cartridge had many irregularities on the end face and was inferior in sealing property on the end face. In addition, despite the fact that the initial collection particle size was larger than that of Example 1, the pressure loss was larger than those of Examples 1 and 2, and the liquid permeability was poor. In addition, foaming and falling off filter media were observed in the filtrate, which was not preferable as a filter.

Comparative Example 2 Short fibers of polypropylene having an average fiber diameter of 17 μm, a cut length of 51 mm, and a number of crimps of 14 were prepared by a usual melt spinning method, and spun to produce a 2 m diameter.
m was obtained. Then, using the apparatus shown in FIG. 2, the hot air flowing out of the air heater 13 is supplied at 15 Nm ³ / min.
It was set to 0 ° C. Then, the spun yarn is used for winding 3.
At 2917, it was wound around the same perforated tubular body as in Example 1 to form a filter cartridge. The both end faces were heated with a hot plate having a surface temperature of 175 ° C. for 5 seconds and welded to obtain a filter cartridge. The evaluation results are shown in Table 1. This filter cartridge was not so different from Comparative Example 1. That is, when the spun yarn was used for the filter cartridge, the effect of heating with the air heater was smaller than when the band-shaped nonwoven fabric was used.

(Comparative Example 3) A filter cartridge was obtained in the same manner as in Example 1 except that the air heater was not used and the film was wound without heating. The evaluation results are shown in Table 1. This filter cartridge was superior to Comparative Examples 1 and 2, but slightly inferior to Example 1 in terms of the pressure loss and the change in the trapped particle size when the pressure was increased. Further, since some swelling was observed in ethyl acetate and xylene, it is considered that long-term use in these solutions is difficult.

[0074]

[Table 1]

[0075]

The filter cartridge of the present invention has better liquid permeability than a conventional thread wound filter cartridge. In addition, it has an excellent feature that there is no foaming and no dropout of the filter medium, which is observed in the conventional thread wound filter.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overview of a filter cartridge of the present invention.

FIG. 2 is an explanatory view showing a state in which a belt-shaped nonwoven fabric is wound by traversing while being heated by an air heater.

FIG. 3 is a conceptual diagram of a spunbond nonwoven fabric.

FIG. 4 is a conceptual diagram of a short fiber nonwoven fabric.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filter cartridge 2 Perforated cylindrical body 3 Converged belt-shaped nonwoven fabric 4 Traverse guide 5 Traverse cam 6 Hoisting arm 7 Hoisting arm shaft 8 Bobbin 9 Banded nonwoven fabric 10 Convergence guide 11 Tension guide 12 Support point guide 13 Air heater 14 Passing particle 15 Span Fibers of bonded nonwoven fabric 16 Intersection points of fibers of spunbonded nonwoven fabric 17 Fibers of nonwoven fabric composed of short fibers

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D019 AA03 BA13 BB02 BB03 BC13 BD03 CA03 CB02 CB06 DA02 DA03 4L047 AA14 AA27 AB03 AB10 BA09 BB09 CA05 CC12

Claims (6)

[Claims] 1. A filter cartridge comprising a band-shaped nonwoven fabric made of thermoplastic fiber wound around a perforated tubular body in a twill shape, wherein at least a part of the contact points or intersections of the wound banded nonwoven fabrics is thermally bonded. Filter cartridge characterized by the following: 2. The fiber constituting the belt-shaped nonwoven fabric has a melting point difference of 1
2. The filter cartridge according to claim 1, which is a composite fiber comprising a low melting point resin and a high melting point resin having a temperature of 0 ° C. or higher. 3. The filter cartridge according to claim 1, wherein the band-shaped nonwoven fabric is a long-fiber nonwoven fabric in which at least a part of fiber intersections is thermally bonded. 4. The filter cartridge according to claim 1, wherein the band-shaped nonwoven fabric is a spunbonded nonwoven fabric. 5. The filter cartridge according to claim 1, wherein the band-shaped nonwoven fabric is a melt-blown nonwoven fabric. 6. The nonwoven fabric according to claim 1, wherein the belt-shaped nonwoven fabric is a nonwoven fabric obtained by laminating at least two layers of a long-fiber nonwoven fabric to which at least a part of fiber intersections are thermally bonded and a melt-blown nonwoven fabric. Filter cartridge described