JP2001054710A - Filter cartridge - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a filter cartridge excellent in water permeability and filtration life. The filter cartridge is formed by winding at least two belt-shaped nonwoven fabrics containing thermoplastic fibers at the same time around a perforated tubular body in a twill shape, and can capture finer particles than conventional thread-wound filter cartridges. Long life, little change in initial collection particle size,
Filter cartridges with low pressure loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a filter cartridge. More specifically, the present invention relates to a liquid filtration filter cartridge in which at least two or more belt-shaped nonwoven fabrics containing thermoplastic fibers are simultaneously wound in a tubular shape, and which has excellent liquid permeability, filtration life, and stability of filtration accuracy.

[0002]

2. Description of the Related Art At present, various filters have been developed and produced for purifying fluids. Above all, 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, purifying industrial water, and the like. Used in a wide range of fields.

Several types of filter cartridges have been proposed. The most typical one is a wound filter cartridge. 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. Another structure is a nonwoven fabric laminated filter cartridge. This is a cylindrical filter cartridge made by winding several types of nonwovens, such as carding nonwovens, on a perforated cylindrical core in a stepwise concentric manner. Have been.

[0004] However, these filter cartridges also have some disadvantages. For example, a foreign matter collecting method of a thread-wound filter cartridge involves collecting foreign matter with fluff generated from a spun yarn, and collecting foreign matter in a gap between the spun yarns. Since it is difficult to adjust the shape, 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. Furthermore, when producing a spun yarn, a small amount of a surfactant is often applied to the surface in order to prevent the short fiber as a raw material from adhering to the spinning machine due to static electricity or the like. When a liquid is filtered with a filter cartridge made of a spun yarn coated with such a surfactant, bubbling of the liquid, TOC (total organic carbon amount), COD (chemical oxygen demand), and an increase in electric conductivity are caused. May adversely affect the cleanliness of the liquid. Further, since the spun yarn is produced by spinning the short fiber as described above, at least two steps of spinning and spinning the short fiber are required, and as a result, the price may be increased.

[0005] The performance of the nonwoven fabric laminated filter cartridge is determined by the nonwoven fabric. In the production of nonwoven fabric, short fibers are entangled with a card machine or air laid machine,
It is often performed by a method of performing heat treatment with a hot air heater or a heating roll as necessary, or a method of directly forming a nonwoven fabric such as a melt blow method or a spun bond method. However, any machine used for nonwoven fabric production, such as a card machine, an air laid machine, a hot air heater, a heating roll, a melt blow machine, and a spun bond machine, often has uneven nonwoven fabric properties such as a basis weight in the machine width direction. As a result, the quality of the filter cartridge may be poor, or the manufacturing cost may be increased by using advanced manufacturing techniques for eliminating unevenness. In addition, it is necessary to use about 2 to 6 types of nonwoven fabrics per type for the nonwoven fabric laminated filter cartridge, and further, it is necessary to use different nonwoven fabrics according to the types of filter cartridges. May be higher.

[0006] In order to solve such problems of the conventional filter cartridge, several methods have been proposed. For example, Japanese Utility Model Publication No. 6-7767 discloses that a filter material having a diameter of about 3 mm is wound around a porous tape-shaped paper by twisting and squeezing the porous tape-shaped paper while twisting the paper, and tightly wound around the porous inner cylinder. There has been proposed a filter cartridge having a different shape. This method has a feature that the winding pitch of the winding can be increased toward the outside of 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 may be permeable.

As another method, Japanese Patent Laid-Open Publication No. 1-145423
In the publication, a filter is proposed in which a bobbin with a large number of fine holes is cut into a strip of cellulose spunbonded nonwoven fabric, and a string is wound through a narrow hole and twisted. ing. If this method is used, it is possible to make a filter that has higher mechanical strength and does not dissolve in water or elute the binder, as compared with a conventional roll tissue filter in which α-cellulose obtained by purifying conventional softwood pulp is made into thin paper and wound into a roll. Is thought to be possible. However,
Cellulose spunbond nonwoven fabric used in this filter is too rigid because it is in the form of paper,
It is difficult to expect foreign matter collection by the filtration material itself, as in the case where a conventional thread-wound filter used to collect foreign matter with its fluff. In addition, the cellulose spunbond nonwoven fabric is in the form of paper, so it easily swells in the liquid, and the swelling causes a decrease in filter strength, a change in filtration accuracy, a decrease in liquid permeability,
Various problems can occur, such as reduced filtration life. In addition, the bonding of fiber intersections of cellulose spunbond nonwoven fabric is often performed by chemical treatment, etc.
The adhesion is often insufficient, and often causes a change in filtration accuracy or a drop of fiber waste, so that it is difficult to obtain stable filtration performance.

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. A filter wound so that the fiber density is 0.18 to 0.30 has been proposed. When this method is used, there is 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. If the division is not uniform, a difference occurs in the collection particle diameter between the well-divided part and the insufficiently-divided part in the nonwoven fabric, so that there is a possibility that the filtration accuracy becomes coarse. In addition, since the strength of the nonwoven fabric may decrease due to the physical stress used when dividing,
There is a possibility that the strength of the manufactured filter is reduced and the filter is easily deformed during use, or the porosity of the filter is changed and the liquid permeability is reduced. Further, when the strength of the nonwoven fabric is low, it is difficult to adjust the tension at the time of winding on the porous core tube, so that fine adjustment of the porosity may be difficult. Furthermore, since the manufacturing cost of the filter is increased due to the spinning technology required for producing easily splittable fibers and the increase in the operating cost during production, if the aforementioned problems in filtration performance are solved, the pharmaceutical industry and electronic It is thought that it can be used in some fields where high filtration performance is required, such as industry, but filters need to be inexpensive like filtration of pool water and filtration of plating solution for plating industry It seems difficult to use for the purpose.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an inexpensive tubular filter cartridge which is excellent in liquid permeability, filtration life, and stability of filtration accuracy.

[0010]

The present invention has the following arrangement. (1) A filter cartridge in which at least two belt-shaped nonwoven fabrics containing thermoplastic fibers are simultaneously wound around a perforated tubular body in a twill shape. (2) The filter cartridge according to the above (1), wherein the belt-shaped nonwoven fabric is a nonwoven fabric containing at least 30% by weight of a thermoplastic fiber. (3) The filter cartridge according to the above (1) or (2), wherein the belt-shaped nonwoven fabric is a thermoplastic long-fiber nonwoven fabric having a width of 3 to 50 mm. (4) The filter cartridge according to any one of (1) to (3), wherein at least a part of the intersections of the fibers of the belt-shaped nonwoven fabric is thermally bonded. (5) The filter cartridge according to any one of (1) to (4), wherein the belt-shaped nonwoven fabric is thermocompression-bonded with a hot embossing roll. (6) The filter cartridge according to any one of (1) to (5), wherein the thermoplastic fiber is a composite fiber comprising a low-melting resin and a high-melting resin, and a difference in melting point between the two resins is 10 ° C. or more. . (7) The width of the belt-shaped nonwoven fabric is defined as L ₁ , L ₂ , L ₃ ,..., L _n (m
m), and the number of windings of the band-shaped nonwoven fabric of each width is N
_{1, N 2, N 3,} ..., when the N _n, wherein in the relation of the following formula (A) (1) ~ ( 6) Filter cartridge according to any one of claim. 7 ≦ (L ₁ × N ₁ ) + (L ₂ × N ₂ ) +... + (L _n × N _n ) ≦ 150 (A) (However, the sum of N ₁ + N ₂ +... + N _n is an integer of 2 or more.) Is.)

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The filter cartridge of the present invention is obtained by winding at least two belt-shaped nonwoven fabrics containing thermoplastic fibers at the same time in a twill shape around a perforated tubular body. In the present invention, the band-shaped nonwoven fabric refers to a nonwoven fabric having a narrow width.

In the present invention, the thermoplastic fiber means 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 include polypropylene, low density polyethylene, high density polyethylene, linear low density polyethylene, copolymerized polypropylene (eg,
Mainly propylene, ethylene, butene-1,4-
Polyolefin-based resins such as binary or multi-component copolymers with methylpentene-1 and the like, polyethylene terephthalate, polybutylene terephthalate, and a low-melting polyester copolymerized by adding isophthalic acid in addition to terephthalic acid as an acid component. Examples include polyester resins such as polyester resins, polyamide resins such as nylon 6 and nylon 66, and thermoplastic resins such as polystyrene, polyurethane elastomer, polyester elastomer, 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. It is preferable to use a resin that can be polymerized with a metallocene catalyst, such as a polyolefin resin or polystyrene, because the properties of the metallocene resin such as improvement in the strength of the nonwoven fabric, improvement in chemical resistance, and reduction in production energy can be utilized in the filter cartridge. These resins may be blended and used to adjust the thermal adhesiveness and rigidity of the nonwoven fabric. Among them, when the filter cartridge is used for filtering an aqueous liquid at room temperature, polyolefin resins such as polypropylene are preferable from the viewpoint of chemical resistance and price, and when used for filtering a relatively high temperature liquid. Polyester resins and polyamide resins are preferred.

It is preferable that the belt-shaped nonwoven fabric used in the present invention contains at least 30% by weight of a thermoplastic fiber. Of course, this thermoplastic fiber may be 100% by weight. 30 thermoplastic fibers contained in the band-shaped nonwoven fabric
When the content is less than 10% by weight, the strength of the nonwoven fabric when thermally bonded by thermocompression bonding or through-air heat treatment is reduced, so that the fibers are liable to fall off during filtration and may be mixed into the filtrate. Fibers other than thermoplastic fibers can be used for the band-shaped nonwoven fabric within a range that does not impair the purpose of the present invention. Examples of other than thermoplastic fibers include rayon, cupra, cotton, hemp, pulp, and the like.
Examples thereof include carbon fibers.

The above-mentioned band-shaped nonwoven fabric is preferably a long-fiber nonwoven fabric using thermoplastic long fibers as thermoplastic fibers in order to improve the strength of the obtained nonwoven fabric and prevent the fibers from falling off the filter. The fibers constituting the long-fiber nonwoven fabric used in the present invention have a melting point difference of 10 ° C. or more, preferably 1 ° C.
When the composite fiber is composed of a low-melting resin and a high-melting resin having a temperature of 5 ° C. or higher, the thermal adhesion at the fiber intersection of the nonwoven fabric is improved. In the case of a resin having no melting point, the flow start temperature is regarded as the melting point. The form of the conjugate fiber may be a form in which the low melting point resin is present on at least a part of the fiber surface, such as a side-by-side type or a sheath-core type. When the thermal adhesion at the fiber intersection improves,
When used as a filter cartridge, the likelihood of particles trapped near the fiber intersections flowing out when the filtration pressure or water flow rises is reduced, and the deformation of the filter cartridge is reduced, and it is also contained in the filtrate. Even if the fibers are deteriorated by the substance, the probability of the fibers falling off is reduced, which is preferable.

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 long-fiber nonwoven fabric can be easily adjusted in the step of bonding the fiber intersections during the production of the long-fiber nonwoven fabric. When used for filtration of a liquid having a relatively high temperature, a combination of a low-melting polyester / polyethylene terephthalate copolymerized with isophthalic acid can also be suitably used.

[0016] The long-fiber nonwoven fabric suitably used in the present invention is a long-fiber nonwoven fabric obtained by a spun bond method or the like. The average single-filament 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 generally difficult to define the average single-filament fineness.
A range of 00 dtex is desirable. Fineness is 3000dte
When x or more is used, there is no difference from the case where a continuous yarn is simply bundled, and there is no point in using a long-fiber nonwoven fabric. Further, by setting it to 0.6 dtex or more, sufficient strength of the nonwoven fabric can be obtained, and the strength of the manufactured filter cartridge is also 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.

In the present invention, the constituent fibers of the band-shaped 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.

Further, when a hydrophilic resin such as polyvinyl alcohol is mixed with a raw material resin of the band-shaped nonwoven fabric or the surface of the band-shaped nonwoven fabric is hydrophilized, for example, when the band-shaped nonwoven fabric is used in an aqueous liquid, It is preferable because the liquid permeability is improved.

The method for thermally bonding the fiber intersections of the belt-shaped 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, a hot through air type, and an infrared heater. And a method using a heat treatment machine such as a mold and a vertical hot air jetting mold. 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.

In order to obtain a band-shaped nonwoven fabric used in the filter cartridge of the present invention, a method of directly forming a band-shaped nonwoven fabric by adjusting the spinning width can be used. More preferably, a method of slitting a wide nonwoven fabric into a band shape is used. Is used.
The slit width at this time is 3 to 50 mm. If the width is smaller than 3 mm, the nonwoven fabric may be cut at the time of slitting. On the other hand, if it is larger than 50 mm, when at least two band-shaped nonwoven fabrics are simultaneously wound around a perforated tubular body in a twill shape, the rigidity of the band-shaped nonwoven fabric becomes too strong. It is difficult to wind tightly because the fiber amount is too large.

The filter cartridge of the present invention is a filter cartridge having excellent water permeability and life by winding at least two band-shaped nonwoven fabrics simultaneously on a perforated cylindrical body, as compared with a case where one band-shaped nonwoven fabric is wound alone. . Further, by adjusting the width and the number of the band-shaped nonwoven fabric to be wound, the filtration accuracy of the filter cartridge can be adjusted more easily than changing the winding conditions.

In this case, it is preferable that the total value of width × basis weight of the band-shaped nonwoven fabric to be wound simultaneously is 200 cm · g / m ² or less. If this value is larger than 200 cm · g / m ² , the rigidity of the band-shaped nonwoven fabric becomes too strong, so that it becomes difficult to wind the nonwoven fabric around a perforated tubular body in a twill shape. It becomes difficult to wind. In addition, when the spinning width is adjusted and the band-shaped nonwoven fabric is directly formed, the preferable range of the basis weight and the nonwoven fabric width is the same as the case where the band is formed by slitting.

The width of the band-shaped nonwoven fabric is defined as L ₁ , L ₂ , L ₃ ,
, L _n (mm), and when the number of windings of the band-shaped nonwoven fabric of each width is N ₁ , N ₂ , N ₃ ,..., N _n , the width is expressed by the following equation (A). X The total value of the number of windings is preferably 7 to 150. However,
The sum of N ₁ + N ₂ +... + N _n is an integer of 2 or more. 7 ≦ (L ₁ × N ₁ ) + (L ₂ × N ₂ ) +... + (L _n × N _n ) ≦ 150 (A) If this value is smaller than 7, the amount of fibers becomes too small, so that the filtration accuracy is reduced. Is difficult to adjust, and if it exceeds 150, the amount of fibers becomes too large and it is difficult to wind tightly. Note that the range of the above formula (A) is the same as that in the case of slitting into a belt-shaped nonwoven fabric when the spinning width is adjusted to directly produce a belt-shaped nonwoven fabric.

The band-shaped nonwoven fabric may be processed by a method described later and then wound around the perforated cylindrical body in a twill shape.
It may be wound as it is without processing. FIG. 2 shows an example of the manufacturing method in this case. The winder used for a normal thread-wound filter cartridge can be used for the winding machine. The supplied band-shaped nonwoven fabric 1 passes through a traverse guide 2 having a narrow hole that moves while traversing, and is wound around a perforated tubular body 4 attached to a bobbin 3 to form a filter cartridge 5. As the traverse guide 2, various guides having narrow holes can be used. For example, a narrow hole having a substantially circular shape, a substantially elliptical shape, a substantially flat shape, or the like can be used. Further, a material having an opening at one end of the narrow hole can be used.

On the other hand, the band-shaped nonwoven fabric may be twisted or bundled to form a pleated material or the like (hereinafter referred to as a band-shaped nonwoven fabric bundle) and then wound in a twill shape on a perforated cylindrical body. FIG. 3 shows an example of a manufacturing method when twisting is applied. Also in this case, a winder used for a normal thread-wound filter cartridge can be used for the winding machine. The traverse guide 2 preferably has a larger hole diameter than the case of FIG. When the twist is applied to the band-shaped nonwoven fabric, the apparent porosity of the band-shaped nonwoven fabric can be changed depending on the number of twists per unit length or the twisting strength, so that the filtration accuracy can be adjusted. The number of twists at this time is preferably in the range of 50 to 1000 times per meter of the band-shaped nonwoven fabric. If this value is less than 50 times, the effect of adding twist is hardly obtained. On the other hand, if this value is more than 1000 times, the produced filter cartridge is inferior in liquid permeability, so that it is not preferable.

When a band-shaped nonwoven fabric bundle is produced, granular activated carbon, an ion-exchange resin or the like may be mixed and processed as long as the effects of the present invention are not impaired. In this case, in order to fix the granular activated carbon or the ion exchange resin, the banded nonwoven fabric may be adhered to the belt-shaped nonwoven fabric with a suitable binder or the like. It may be thermally bonded to the fiber.

Next, a method for winding the band-shaped nonwoven fabric will be described. The bobbin of this winder has a diameter of about 10-4
A perforated tubular body having a length of about 0 mm and a length of about 100 to 1000 mm is mounted, and a band-shaped nonwoven fabric (or a bundle of banded nonwoven fabrics) is fixed to an end of the perforated tubular body through a winding path of a winder.
The perforated tubular body serves as a core material of the filter cartridge, and its material and shape are not particularly limited as long as they have strength enough to withstand external pressure during filtration and pressure loss is not extremely high. For example, an injection molded product obtained by processing polyethylene or polypropylene into a net-like cylindrical shape like a core material used in a normal filter cartridge may be used, or a material obtained by processing ceramic or stainless steel in the same manner may be used. . 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. Since the yarn path of the winder is swung in a twill shape by a traverse cam installed parallel to the bobbin, a band-shaped nonwoven fabric is swung in a twill shape around the perforated tubular body. The winding conditions at that time may be set in accordance with the production of a normal thread-wound filter cartridge. For example, the bobbin may be wound at an initial speed of 1,000 to 2,000 rpm while adjusting the feeding speed and applying an appropriate tension. The porosity of the filter cartridge can be changed by the tension at this time. Furthermore, the tension at the time of winding is adjusted to make the porosity of the inner layer dense,
The porosity can be made coarser as it is wound around the middle layer and the outer layer. The filtering accuracy can also be changed by adjusting the ratio between the traverse speed of the traverse cam and the rotation speed of the bobbin to change the winding pattern. The method of applying the pattern can 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. By these methods, 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 4 to form a filter cartridge. This may be used as it is as the filter cartridge 5,
For example, a gasket made of foamed polyethylene having a thickness of about 3 mm may be attached to the end face to increase the adhesion of the filter cartridge end face to the housing.

The liquid permeability can be improved by making a cut or making a hole in the band-shaped nonwoven fabric. In this case, the number of cuts is suitably about 5 to 100 per 10 cm of the band-shaped nonwoven fabric, and when a hole is to be formed, the ratio of the area of the opening is preferably about 10 to 80%. Also, when simultaneously winding a plurality of band-shaped nonwoven fabrics around a perforated tubular body, the filtration performance can be adjusted by winding other yarns such as spun yarns together. Also,
At the same time, when a plurality of band-shaped nonwoven fabrics are wound by traversing, a wide nonwoven fabric can be wound in to adjust the maximum particle outflow diameter when a filter cartridge with coarse accuracy is produced.

[0029]

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 example, the evaluation of the physical properties, filtration performance, and the like of the filtering material was performed by the methods described below.

The area and the thickness of the band-shaped nonwoven fabric are 62
The band-shaped nonwoven fabric was cut out so as to have a size of 5 cm ² , the weight was measured, and the weight was converted to the weight per 1 m ^{2 of} the band-shaped nonwoven fabric to obtain the basis weight. In addition, the thickness of the cut nonwoven fabric was arbitrarily measured at ten points, and the average of eight points excluding the maximum value and the minimum value was defined as the thickness of the nonwoven fabric.

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

(Yarn spacing) The spacing between the band-shaped nonwoven fabric or spun yarn, etc., on the surface layer of the filter cartridge and the band-shaped nonwoven fabric, spun yarn, etc. wound on the layer immediately below it.
(FIG. 1) was measured at 10 points for one filter cartridge, and the average was taken as the yarn interval.

(Initial Collection Particle Size, Initial Pressure Drop, Filtration Life) 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. The pressure loss before and after the filter cartridge at this time was defined as the initial pressure loss. Next, eight kinds of test powder I (abbreviated as JIS kind 8) specified in JIS Z 8901 in the circulating water.
6 to 8.6 μm) and the same 7 types (abbreviated as JIS type 7; median diameter: 27 to 31 μm) were continuously added at a weight ratio of 1: 1 at a rate of 0.4 g / min. After 5 minutes, the stock solution and the filtrate were collected, diluted at an appropriate magnification, and the number of particles contained in each solution was measured using a light-blocking particle detector to calculate the initial collection efficiency. Further, by interpolating the values, a particle size showing a collection efficiency of 80% was obtained. Also,
Further, the cake was further added, and when the pressure loss of the filter cartridge reached 0.2 MPa, the undiluted solution and the filtrate were similarly collected, and the trapped particle size at 0.2 MPa was determined.
The time from the start of cake addition to the time when the pressure reached 0.2 MPa was defined as the filtration life. The filtration life is 1000
When the differential pressure did not reach 0.2 MPa even when the pressure reached minutes, the measurement was stopped at that point.

(Foaming of Initial Filtrate and Dropping of Fiber) One filter cartridge is attached to the housing of the circulation type filtration performance tester, and the flow rate is adjusted to 10 liters per minute by a pump, and ion-exchanged water is passed through. One liter of the initial filtrate was collected, of which 25 cm ³ was collected in a colorimetric bottle and stirred vigorously, and foaming was observed 10 seconds after the stirring was stopped. Then, the volume of the foam (the volume from the liquid surface to the top of the foam) is 10c.
x if less than m ³ , less than 10 cm ³ and diameter 1 mm
Bubble was judged as △ when 5 or more of the above bubbles were seen, and ○ when less than 5 bubbles with a diameter of 1 mm or more. In addition, 500 cm ³ of the initial filtrate was passed through a nitrocellulose filter paper having a pore size of 0.8 μm, and when there were 4 or more fibers having a length of 1 mm or more per 1 m ^{2 of} the filter paper, x; The case was evaluated as ○, and fiber shedding was determined.

(Example 1) As a long-fiber nonwoven fabric, the basis weight 2
2 g / m ² , thickness 200 μm, fineness 2 dtex,
A polypropylene spunbonded nonwoven fabric whose fiber intersections were thermocompressed with a hot embossing roll was used. 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. The long-fiber nonwoven fabric was slit into a width of 30 mm and 20 mm to obtain a belt-shaped long-fiber nonwoven fabric. Then, using a winder, one strip-shaped long-fiber nonwoven fabric is simultaneously wound around the perforated tubular body at the same time, and the winding number is set to 3.273 so that the interval between the strip-shaped long-fiber nonwoven fabrics is 0 mm at an initial spindle speed of 1500 rpm.
And wound around a perforated cylindrical body until the outer diameter becomes 62 mm, and the cylindrical filter cartridge 5 as shown in FIG.
I got Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge had a trapped particle size of about 8 μm, and had good water permeability and other filtration properties. In particular, there was little decrease in filtration accuracy when the pressure was increased, and the filter cartridge was excellent in filtration life.

(Example 2) Except for adjusting the number of winds to be 3.714 and adjusting the number of band-shaped long-fiber nonwoven fabrics having a width of 30 mm and 20 mm to a total of four, each of which was simultaneously wound around a perforated cylindrical body at a time. A filter cartridge was obtained in the same manner as in Example 1. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. The filtration performance of this filter cartridge became coarser than that of Example 1 by increasing the number of the band-shaped long-fiber nonwoven fabrics.

(Example 3) A filter cartridge was obtained in the same manner as in Example 1 except that the number of winds was adjusted to 4.429. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. The filtering performance of this filter cartridge became coarser than that of Example 1 by changing the winding conditions.

(Example 4) A filter cartridge was manufactured in the same manner as in Example 1 except that the number of winds was adjusted to 4.273, and four band-shaped long-fiber nonwoven fabrics each having a width of 40 mm were simultaneously wound around a perforated cylindrical body. I got Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. The filtering performance of this filter cartridge was coarser than that of Example 1 by increasing the number of the band-shaped long-fiber nonwoven fabrics by increasing the width.

(Example 5) A filter cartridge was manufactured in the same manner as in Example 1 except that the number of winds was adjusted to 3.476, and two strip-shaped long-fiber nonwoven fabrics having a width of 3 mm were simultaneously wound around a perforated cylindrical body. I got Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. The filtration performance of this filter cartridge was not much different from that of Example 1, but the time required for winding was longer than that of Example 1.

Example 6 A cylindrical filter cartridge was obtained in the same manner as in Example 3 except that nylon 66 was used as the raw material resin for the long-fiber nonwoven fabric. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge showed almost the same filtration performance as that of Example 3.

Example 7 A cylindrical filter cartridge was obtained in the same manner as in Example 3 except that the raw material resin for the long-fiber nonwoven fabric was polyethylene terephthalate. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge showed almost the same filtration performance as that of Example 3.

(Example 8) As the constituent fibers of the long-fiber nonwoven fabric, the low-melting-point component was high-density polyethylene (melting point: 133
° C), the high melting point component is polypropylene (melting point: 165 ° C)
A cylindrical filter cartridge was obtained in the same manner as in Example 3 except that a sheath-core composite fiber having a weight ratio of 5: 5 was used. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge was finer in precision than in the case of Example 3, and was a filter cartridge excellent in stability of filtration accuracy in which the collected particle size at 0.2 MPa hardly changed from the initial collected particle size. .

Example 9 A cylindrical filter cartridge was obtained in the same manner as in Example 8 except that linear low-density polyethylene (melting point: 122 ° C.) was used as the low melting point component. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge had the same filtration accuracy as that of Example 8, and was more excellent in water permeability than Example 8.

Example 10 A cylindrical filter cartridge was obtained in the same manner as in Example 9 except that the method of thermocompression bonding of fiber intersections was changed from using a hot embossing roll to using a through air heater. . Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge was slightly coarser than in the case of Example 9.

Example 11 The fineness of a long-fiber nonwoven fabric was set to 10
Except for changing to dtex, in the same manner as in Example 3,
A cylindrical filter cartridge was obtained. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge had a higher accuracy than the case of Example 3.

(Example 12) The basis weight of the long-fiber nonwoven fabric was 44
g / m ² except for the same method as in Example 3.
A cylindrical filter cartridge was obtained. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. The accuracy of this filter cartridge was coarser than in the case of the third embodiment, and was almost the same as that of the second embodiment.

(Comparative Example 1) A filter cartridge was obtained in the same manner as in Example 1 except that one 50-mm wide band-shaped long-fiber nonwoven fabric was wound around a perforated cylindrical body as it was. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. The filtration accuracy of the filter cartridge was equivalent to that of Example 1, but the water permeability was poor and the filtration life was poor.

Comparative Example 2 A cylindrical filter cartridge was obtained in the same manner as in Comparative Example 1 except that the number of winds was adjusted to 4.429. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge exhibited almost the same filtration performance as that of Comparative Example 1.

Comparative Example 3 A cylindrical filter cartridge was obtained in the same manner as in Example 3 except that a polypropylene spun yarn having a diameter of 2 mm obtained by spinning a fiber having a fineness of 3 dtex was used instead of the band-shaped long fiber nonwoven fabric. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. In this filter cartridge, the initial collection particle size was considerably coarser than in Example 3, and was almost the same as that in Example 2. However, the water permeability was poorer than in the case of Example 2, and the filtration life was also poorer. In addition, the initial filtrate had foaming, and the filter medium was found to fall off.

(Comparative Example 4) JIS P 3801 cut into a width of 30 mm and a width of 20 mm instead of the band-shaped long-fiber nonwoven fabric
A cylindrical filter cartridge was obtained in the same manner as in Example 3 except that one kind of filter paper specified in Example 1 was used. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. This filter cartridge had an initial trapping particle diameter smaller than that of Example 3 and coarser than that of Example 1, but had a large initial pressure loss, and the trapping particle diameter at the time of pressure increase was lower than that of Example 1. It had changed a lot. Furthermore, the filtration life was extremely short. In addition, the filter medium was found to fall off in the initial filtrate.

Comparative Example 5 Polypropylene (melting point: 16)
5 d) and high-density polyethylene (melting point: 133 ° C.), a 4 dtex fineness, 8-split type split short fiber is formed into a web by a carding machine, and subjected to fiber splitting and fiber entanglement by high pressure water processing to obtain a basis weight of 22 g / m ^2. Of non-woven fabric of split short fiber was obtained. As a result of observing this nonwoven fabric with an electron microscope and performing image analysis, 50% by weight of all the fibers were divided into fineness of 0.5 dtex. A cylindrical filter cartridge was obtained in the same manner as in Example 3 except that this nonwoven fabric was cut into widths of 30 mm and 20 mm and used in place of the band-shaped long-fiber nonwoven fabric. Table 1 shows the configuration of the filter cartridge and the measurement results of the filtration performance. Although this filter cartridge had a smaller initial collection particle size than that of Example 3, the collection particle size at 0.2 MPa was almost the same. Also,
Some bubbling was seen in the initial filtrate, and fiber shedding was also seen.

[0052]

[Table 1]

[0053]

The filter cartridge of the present invention can capture fine particles, has a long filtration life, hardly changes the initial collection particle size, and has a low pressure loss, as compared with the conventional thread wound filter cartridge. Things are obtained.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view showing a state in which a belt-shaped nonwoven fabric is wound as it is without processing.

FIG. 3 is an explanatory view showing a state in which a belt-shaped nonwoven fabric is wound while being twisted.

[Description of Signs] 1: Band-shaped nonwoven fabric or bundle thereof 2: Traverse guide 3: Bobbin 4: Perforated cylindrical body 5: Filter cartridge 6: Wound around a certain band-shaped nonwoven fabric or spun yarn and one layer below The distance between the banded nonwoven fabric or spun yarn

Claims (7)

[Claims] 1. A filter cartridge comprising at least two belt-shaped nonwoven fabrics containing thermoplastic fibers wound simultaneously around a perforated tubular body in a twill shape. 2. A nonwoven fabric comprising at least three thermoplastic fibers.
The filter cartridge according to claim 1, which is a nonwoven fabric containing 0% by weight. 3. The filter cartridge according to claim 1, wherein the band-shaped nonwoven fabric is a thermoplastic long-fiber nonwoven fabric having a width of 3 to 50 mm. 4. The filter cartridge according to claim 1, wherein at least a part of intersections of the fibers of the band-shaped nonwoven fabric is heat-bonded. 5. The filter cartridge according to claim 1, wherein the band-shaped nonwoven fabric is thermocompression-bonded with a hot embossing roll. 6. The filter cartridge according to claim 1, wherein the thermoplastic fiber is a composite fiber comprising a low-melting resin and a high-melting resin, wherein the difference between the two resins is 10 ° C. or more. 7. The band-shaped nonwoven fabric has a width of L ₁ , L ₂ , L _{3 ,.}
(Mm) and the number of windings of the band-shaped nonwoven fabric of each width is N ₁ , N ₂ , N ₃ ,..., N _n . The filter cartridge according to 1. 7 ≦ (L ₁ × N ₁ ) + (L ₂ × N ₂ ) +... + (L _n × N _n ) ≦ 150 (A) (However, the sum of N ₁ + N ₂ +... + N _n is an integer of 2 or more.) Is.)