JP2002028458A - Precision filtration filter cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cartridge filter for precision filtration which can be suitably used in a manufacturing process or the like of a semiconductor or a medicine or the like, is excellent in chemical resistance and further has a large filtration flow rate. SOLUTION: A precision filtration filter cartridge is distinguished by that a pleat is constituted of a micro-porous filter membrane, a membrane support, a core, an outer peripheral cover and two end plates, (1) a large number of minute recessed parts, grooves and/or projected parts are formed on the micro- porous filter membrane or (2) the membrane support is composed of a micro- porous membrane on which a large number of minute recessed parts, grooves and/or projected arts are formed or a film in which a large number of holes are made and further on which a large number of minute recessed parts, grooves and/or projected parts are formed and further is provided only at any one side among a primary side or a secondary side of the micro-porous filter membrane. In particular, a constituting member of the filter cartridge is preferably made of a polysulfone polymer or a fluororesin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the removal of germs and fine turbid particles during the production of pharmaceuticals such as injection solutions and eye drops.
Using a microporous filtration membrane used for removing microbes and fine suspended particles in the container filling process of mineral water, draft beer and sake, or for removing fine suspended particles in water and chemicals used in the semiconductor manufacturing process Related to cartridge filters. The present invention particularly relates to a cartridge filter using a microporous microfiltration membrane which is excellent in chemical resistance and flow characteristics and is inexpensive, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, in the production of semiconductors, there has been a demand for a filter for filtration which has high resistance to chemicals such as organic solvents, acids, alkalis and oxidizing agents and has a small amount of eluted substances. At present, for filtering such a chemical solution, a microporous microfiltration membrane made of polytetrafluoroethylene resin (abbreviated as PTFE) is used, and a fluorine-based polymer is also used for filter components other than the filtration membrane. A filter for filtration is used. However, this so-called all-fluorine filter is expensive, and an inexpensive chemical-resistant filter is required. Although an increase in the filtration flow rate is also desired, there is a problem that it is difficult to increase the installation area of the filtration membrane more than the present, and therefore it is difficult to increase the filtration flow rate.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an acid, an alkali, an oxidizing agent or an alcohol frequently used in a semiconductor manufacturing process. To provide an inexpensive filter cartridge that is resistant to high-temperature filtration of a mixed solution of the above and isopropanol at 60 ° C. to 80 ° C. A still further object is to increase the filtration flow rate by increasing the filter membrane installation area in the cartridge.

[0004]

The present inventor has studied a pleated microfiltration filter cartridge composed of a microporous filtration membrane, a membrane support, a core, an outer peripheral cover, and two end plates. As a porous filtration membrane, by using one having a large number of fine recesses, grooves and / or projections formed thereon, or by using only one membrane support on either the primary side or the secondary side of the filtration membrane. It has been found that the above objective can be achieved. Further, in addition to the above, as a film support, a microporous film in which a large number of fine concave portions, grooves, and / or convex portions are formed, or a further large number of holes are formed after forming a large number of fine concave portions, grooves, and / or convex portions. Invented by using a modified film, the filtration area inside the cartridge can be further increased, and the members of the microfiltration filter cartridge are limited to polysulfone resin or perfluoro resin, thereby improving heat stability and chemical resistance. It has been found to contribute to the purpose. Based on these facts, the following invention has been reached.

(1) A pleated type microfiltration filter cartridge comprising a microporous filtration membrane, a membrane support, a core, an outer peripheral cover and two end plates, wherein micropores and grooves are formed on the microporous filtration membrane. And / or a microfiltration filter cartridge having a large number of projections.

(2) A pleated microfiltration filter cartridge comprising a microporous filtration membrane, a membrane support, a core, an outer peripheral cover, and two end plates, wherein the membrane support has fine recesses, grooves and / or protrusions. A film in which a number of fine concave portions, grooves and / or convex portions are formed by opening a large number of microporous films or a number of holes,
A microfiltration filter cartridge characterized in that only one membrane support is used on either the primary side or the secondary side of the microporous filtration membrane.

(3) The microfiltration filter cartridge according to (2), wherein the microporous filtration membrane is formed with a large number of fine concaves, grooves, and / or convexes.

(4) The microporous filtration membrane and the membrane support constituting the filter cartridge are made of polytetrafluoroethylene resin (PTFE), and the core, the outer peripheral cover and the end plate are made of tetrafluoroethylene.
Perfluoroalkyl vinyl ether copolymer resin (PF
(1) to (1) to (4), characterized by being made of one or both of A) and a tetrafluoroethylene / hexafluoropropylene copolymer resin (PEP).
The microfiltration filter cartridge according to any one of (3).

(5) The above (1) to (3), wherein the microporous filtration membrane, the membrane support, the core, the outer peripheral cover and the end plate constituting the filter cartridge are all made of a polysulfone-based polymer. ) The microfiltration filter cartridge according to any one of the above items. Hereinafter, the present invention will be described in detail.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter cartridge includes a pleated cartridge having a structure in which a filtration membrane and a membrane support for protecting the filtration membrane are folded in a pleated shape, and a flat plate laminated cartridge formed by laminating a plurality of flat plate filtration units. It has been known. About the structure of the pleated cartridge,
Examples thereof are disclosed in, for example, JP-A-4-235722 and JP-A-10-66842. Regarding the structure of the flat plate laminated cartridge, see, for example, JP-A-63-80815 and JP-A-56-129.
Nos. 016 and 58-98111. The present invention is an invention particularly applied to a pleated cartridge.

Hereinafter, the structure of the pleated cartridge will be described. FIG. 1 is a developed view showing the entire structure of a typical pleated microfiltration membrane cartridge filter which has been conventionally used and can be applied to the present invention. The microfiltration membrane 3 is folded while being sandwiched by two membrane supports 2 and 4 and wound around a core 5 having many liquid collecting ports. An outer cover 1 is provided on the outside of the outer cover 1 to protect the microfiltration membrane 3. The microfiltration membrane 3 is sealed at both ends of the cylinder by end plates 6a and 6b. The end plates 6a and 6b are connected via a gasket 7 to a filter housing (not shown).
Contact with the seal part of One end plate 6a, 6b
There is also a type in which an O-ring is provided to the filter housing via the O-ring. Gasket or
The O-ring can be easily removed when the used filter cartridge is discarded. The filtered liquid is collected from the liquid collecting port of the core 5 and discharged from the fluid outlet 8 provided at the end of the cylinder through the hollow part of the core 5. The fluid outlet 8 may be provided at both ends of the cylinder, or may be of a type in which the fluid outlet 8 is provided at only one end and one end is closed.

FIG. 2 is a developed view showing an embodiment of a structure of a pleated microfiltration cartridge filter which is particularly preferable for the present invention. The microfiltration membrane 3 is crimped together with only one membrane support 4 on the secondary side and wound around a core 5 having a large number of liquid collection ports (the membrane support is only on the secondary side). As in the case of the cartridge filter of FIG. 1 which has been conventionally used, an outer peripheral cover 1 is provided outside the cartridge filter to protect the microfiltration membrane 3. The microfiltration membrane 3 is sealed at both ends of the cylinder by end plates 6a and 6b. The end plate is in contact with a seal portion of a filter housing (not shown) via a gasket 7. There is also a type in which an O-ring is provided on one end plate portion and is in contact with the filter housing via the O-ring. The gasket or O-ring can be easily removed when the used filter cartridge is discarded. The filtered liquid is collected from the liquid collecting port of the core 5 and discharged from the fluid outlet 8 provided at the end of the cylinder through the hollow part of the core 5. The fluid outlet 8 may be provided at both ends of the cylinder, or may be of a type in which the fluid outlet 8 is provided at only one end and one end is closed. A structure in which a membrane support is provided on the primary side instead of the secondary membrane support 4 is also within the scope of the present invention as a suboptimal filter cartridge. In the following description of the present invention, the numbers given to the members of the filter cartridge are the member numbers of the respective members in the configuration diagrams of FIGS.

Known materials for the microfiltration membrane 3 include aromatic polyarylethersulfone, polyethylene, polypropylene, cellulose esters, polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polyamide and the like. Among them, polytetrafluoroethylene (PTF
E) and aromatic polyaryl ether sulfones (hereinafter referred to as polysulfone polymers) are preferred materials. A hydrophilic membrane made of an aromatic polysulfone-based polymer is preferable because it has excellent heat resistance and chemical resistance to a wide range of chemicals. Typical chemical structures of the polysulfone-based polymer are shown in general formulas (I) to (III). The polymer represented by the general formula (I) is well known under the common name of "polysulfone" and is marketed by Amoco under the trade name Udel Polysulfone. On the other hand, the polymer represented by the general formula (II) is well known under the common name of "polyether sulfone" and is sold by Sumitomo Chemical under the trade name of Sumika Excel PES. In the present invention, the use of polyethersulfone is particularly preferred because of its excellent chemical resistance to a wide range of chemicals. A method for producing a hydrophilic microporous microfiltration membrane using a polysulfone-based polymer as a material is disclosed in JP-A-56-154051.
No., JP-A-56-86941, JP-A-56-12640, JP-A-62-2
No. 7006, JP-A-62-258707, JP-A-63-141610 and the like.

[0014]

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On the other hand, PTFE is preferable as a microporous microfiltration membrane material because it is very excellent in a sense different from a polysulfone-based polymer. That is, it is characterized in that it has stable chemical resistance to almost any chemical, and can be formed into a film. The production method of the PTFE microporous microfiltration membrane is described in JP-B-57-18991, JP-A-54-97686, JP-A-55-1.
No. 08425 and Japanese Patent Publication No. 7-119303.

Although polyethylene does not have heat resistance, it is excellent in that it has chemical resistance to most chemicals used at low temperatures and is relatively inexpensive. The method for producing a polyethylene microporous microfiltration membrane is described in JP-A-60-255107 and JP-B-7-177782.
No. and other publications. The pore size of the filtration membrane is usually from 0.02 μm to 5 μm.
Those having a display hole diameter of from 0.02 μm to 0.2 μm are particularly preferable in the case of manufacturing highly integrated ICs. The properties of such a membrane can be expressed as a water bubble point value measured by the method of ASTM F316 of 0.3 MPa or more, and can be expressed as an ethanol bubble point of 0.1 to 1 MPa. Particularly preferably, the ethanol bubble point is 0.3 to 0.7 MPa. It is preferable that the ratio of the pores to the apparent volume is large because the filtration resistance is small. However, if the pores are too large, the membrane strength is reduced and the membrane is easily broken. Thus, the preferred porosity of the filtration membrane is between 40% and 90%, and particularly preferred is between 57% and 85%. The film thickness is
If the thickness is too large, the film area that can be incorporated into the cartridge will decrease, and if it is too thin, the film strength will decrease.
0 μm, and the preferred film thickness is 50 μm to 160 μm.
It is. A more preferred film thickness is from 70 μm to 135 μm.

When two membrane supports are used, the microfiltration membrane 3 is sandwiched between the membrane supports 2 and 4, and when one more preferable membrane support is used, the secondary membrane support 4 (in some cases) is used. Is pleated with a membrane support 2) by a generally known method. In the pleated cartridge of the present invention, a non-woven fabric, a woven fabric, a net, or the like is used as the membrane support, and the materials used for the microfiltration membrane and the fluororesin material described below can be used.
Preferred material configurations are those in which each filter member is entirely composed of a fluororesin material (referred to as an all-fluorine filter) and those in which all filter members are composed of a polysulfone-based polymer material (referred to as an all-sulfone filter). Non-woven or net-like membrane supports made of PFA (perfluoroalkoxy resin) are known for all fluorine filters.
More expensive than membranes. The role of the membrane support is to reinforce the filtration membrane against fluctuations in filtration pressure, to permeate the liquid from the liquid supply side to the filtration side, and to introduce liquid into the back of the pleated pleats in a direction parallel to the filtration membrane. I also carry. Therefore, it is necessary to have appropriate liquid permeability and physical strength enough to protect the filtration membrane. Any sheet material having such a function can be used, but in the conventional general-purpose filtration apparatus, a polyester or polypropylene nonwoven fabric has been used in most cases because of its low cost and excellent performance.

The membrane support usable in the present invention includes:
In addition to the above general functions, heat resistance and chemical resistance are required, and a device (material and shape) for increasing the filtration flow rate is required. With respect to heat resistance and chemical resistance, it is preferable to use the same material as the filtration membrane 3 or a higher polymer material.
Polysulfone-based polymers and PTFE have both heat resistance and chemical resistance, and are particularly preferred.Since polysulfone-based polymer fibers and PTFE fibers have not been manufactured, use of polysulfone-based polymers and PTFE nonwoven fabrics, woven fabrics and nets is not possible . Also, non-woven fabrics and nets made of PFA used in all-fluorine filters are extremely expensive,
This causes the all-fluorine filter to be expensive. Furthermore, since the nonwoven fabric and the net are bulky, a conventional pleated filter cartridge with an outer diameter of 70 mm has a maximum of 15
There is also a problem that a satisfactory filtration flow rate cannot be obtained because only five pleated pleats can be incorporated and the area of the incorporated filtration membrane is small. In the present invention, these problems have been solved by the following support in which a microporous membrane or a perforated film is further embossed.

In other words, in the present invention, it is possible to use an inexpensive filter cartridge having a large number of pleated pleats. In the filter cartridge of the present invention, as a membrane support, a microporous membrane having a large pore diameter (not a woven or nonwoven fabric) made of the same material as the filtration membrane
The use of is preferred. The manufacturing method is basically the same as the microporous microfiltration membrane described above, but the water bubble point of the microporous membrane used for the membrane support is preferably 20 to 150 kPa, and if it is 40 to 100 kPa, preferable. The water permeability in the direction perpendicular to the membrane support surface is preferably at least 150 ml / cm2 per minute when a differential pressure of 0.1 MPa is applied,
More preferably, it is 200 ml / cm2 or more. It is preferable that the Murren burst strength of the membrane support is 80 kPa or more, and 1
It is more preferable that the pressure be 20 kPa or more.

The membrane support used in the present invention has concave portions and / or concave portions.
Alternatively, the method for providing the convex portions is not particularly limited. This object can be achieved by emboss calendering in which a microporous film is continuously pressed between a metal roll having a large number of projections formed on its surface and a backup roll having a flat surface. When a hard backup roll is used, only a recess is formed in the membrane support. When a soft backup roll is used, a projection is simultaneously formed on the opposite surface of the concave portion. Since the pores are crushed in the concave portion and the water permeability is lost, it is preferable that the concave portion forming area be less than half of the entire support film.

In this case, the concave portion provided to the membrane support and
The (or) convex portions may be provided on only one surface of the support film, or may be provided on both surfaces. The depth of the unevenness given to the membrane support can be used from 5 μm to 0.25 mm, and from 20 μm
0.15 mm is preferable, and 50 μm to 0.1 mm is more preferable.
Further, the intervals and depths of the formed concave portions and / or convex portions need not be constant everywhere. The concave portion and / or the convex portion may have a circular or polygonal shape independent of each other. However, the membrane support having a structure in which the concave portions or the convex portions communicate with each other to form a groove or a mountain may be formed by the communicating groove. Through
Alternatively, the liquid can flow in the plane direction along the mountains,
Particularly preferred. It is even more preferred if the grooves of the membrane support consist of a number of longitudinal and transverse grooves which intersect each other. The width of the groove is preferably in the range of 5 to 1000 μm, and 20 to 40
More preferably, it is in the range of 0 μm, particularly preferably in the range of 50 to 200 μm. The distance between the grooves is preferably 4 mm or less even at a wide place, more preferably 0.15 mm or more and 2 mm or less.

The thickness of the microporous membrane used for the membrane support is 60
μm to 300 μm is preferred, and 100 μm to 190 μm is particularly preferred. The thickness of the film used for the membrane support is
It is preferably from 25 μm to 125 μm, particularly preferably from 50 μm to 100 μm. In any case, if it is too thin, the function of reinforcing the filtration membrane is inferior. If it is too thick, pleating becomes difficult, and the membrane area that can be incorporated into the cartridge is inconvenient. When a single membrane support is used on the secondary side of the filtration membrane, it is easy to create a structure that is strong against filtration pressure, and a large filtration area can be taken in a limited volume, increasing the filtration flow rate. It can contribute to the object of the present invention.

In the present invention, grooves and peaks or recesses (or)
It is also possible to use a membrane support in which a hole is physically formed in a polysulfone-based polymer film provided with a convex portion. The method of making a hole in the polymer film is not particularly limited, and examples thereof include a method using a punch, a method using a sharp needle, a method using a laser, and a method using a water jet. The size of the hole is the diameter,
Those having a size and shape corresponding to a circle, ellipse, or rectangle having a major axis or one side of 10 μm to 5 mm can be used. The preferred size of the hole is from 30 μm to 1.5 mm in diameter, major axis or one side, particularly preferably from 60 μm to 0.5 mm. The ratio of the hole area to the membrane support area is 10
It can be used in the range from to 90%. If the hole area ratio is too small, the filtration resistance will be too large, while if the hole area ratio is too large, the mechanical strength will be reduced and the microporous filtration membrane will not be reinforced. When drilling a large hole, a large hole area ratio is required, and when drilling a small hole, a relatively small hole area ratio is sufficient.

In the membrane support of the present invention, it is particularly preferable that all the previously drilled holes have grooves. The pattern of the protrusions formed on the opposite surface of the groove as the groove is formed may be continuous with each other or may be isolated from each other, but may be continuous with each other. Is preferred. This is because when embossing is performed, the convex part and the concave part have a front and back relationship, so the convex part isolated when viewed from one surface is discontinuous and isolated when viewed from the opposite surface This is because a concave portion will be formed.

The large pore microporous film and the perforated film having the grooves and the projections are small in volume, so that the number of folds which can be incorporated in the filter cartridge can be increased as compared with the case where a nonwoven fabric or a net is used. Conventionally, the membrane support used on both sides of the primary and secondary sides of the filtration membrane is only one of the primary side and the secondary side of the filtration membrane. be able to.

As a material for supporting a membrane, a fluorinated resin which is preferable together with a porsulfone resin material has excellent chemical resistance, so that PCTFE (polychlorotrifluoroethylene), ETFE (ethylenetetrafluoroethylene), FEP
(Tetrafluoroethylene / hexafluoropropylene copolymer) and PFA (tetrafluoroethylene / perfluoroalkylvinyl ether copolymer).
Among them, PFA is particularly preferred in terms of chemical resistance and heat resistance.

In the present invention, it is preferable to provide the microporous filtration membrane with concave portions, grooves and / or convex portions. This is to make it easier to feed the liquid in the direction parallel to the membrane surface behind the pleat folds. The shape and the number of concave portions, grooves and / or convex portions to be formed are as follows.
This is exactly the same as the case of forming concave portions, grooves and / or convex portions on the microporous film for membrane support.

The microporous filtration membrane having the concave portions, grooves and / or convex portions and the membrane support are overlapped and pleated by a usual method. When using the membrane support on the secondary side, if the groove of the membrane support is directed to the secondary side, the groove of the microporous filtration membrane is directed to the primary side, and two sheets are overlaid and pleated, the liquid will easily pass through It is preferable. The reverse is true when using a membrane support on the primary side. It is preferable to use the membrane support on the secondary side of the filtration membrane because a larger flow rate can be obtained. Pleated fold pitch (interval between fold and next fold)
Is typically 9 to 12 mm. In the case of a filter cartridge with an outer diameter of 70 mm, 17.5 m of 1/4 of the outer diameter in theory
With a pitch of m, the largest number of filtration membranes can be incorporated (the number of folds is the largest). However, the pitch is preferably 12 mm or less because of the need to impart repeated durability to fluctuations in filtration pressure. Most preferred is a range of 10 to 11 mm.

The pleated filter medium is trimmed at both ends with a cutter knife or the like in order to align both ends, then rounded into a cylindrical shape, and the seams of the joint are heat-sealed or liquid-tightly sealed with an adhesive. . The adhesive seal is performed by combining the microfiltration membrane and the membrane support in total of four layers. Heat sealing may be performed with a thermoplastic sheet interposed between the folds. As the adhesive or the thermoplastic sheet used here, the same material as the filtration membrane is preferable in order to improve the adhesiveness. When an adhesive is used, for example, a polysulfone-based polymer adhesive is used after being dissolved in a solvent. For example, 10 parts of polyether sulfone is dissolved in a mixed solution of 30 parts of methylene chloride and 20 parts of diethylene glycol, and 140 parts of diethylene glycol is gradually added and mixed. The solvent is heated and volatilized after bonding and does not remain in the filter cartridge. When PTFE is used for the filtration membrane material, the heat sealing method is adopted.

The core 5 is inserted inside the cylindrical filter medium thus formed, and the outer peripheral cover 1 is covered with the core 5 is called a pleated body. The outer peripheral cover 1 and the core 5 are provided with a number of slit-shaped windows to allow the liquid to easily permeate and protect the pleated pleats against pressure from the direction of filtration or the opposite direction. When the primary membrane support for protecting the filtration membrane is omitted and the membrane support is used only on the secondary side, the dimension of the window provided on the outer peripheral cover in the cylindrical axis direction is 3 mm or less, particularly preferably 2 mm or less and 1 mm or more. By doing so, the function of protecting the outer peripheral cover against back pressure is improved. The size of the window in the circumferential direction is not particularly limited, but a range of 10 mm to 50 mm is appropriate. Similarly, when the membrane support is used only on the primary side of the filtration membrane, the size of the window provided in the core in the cylindrical axis direction is 3 mm or less, particularly preferably 2 mm or less and 1 mm or more. The end sealing step of bonding both ends of the pleated body to the end plate 6 in a liquid-tight manner is performed by a method using heat melting.
It can be broadly divided into the method by solvent bonding. In the hot melting method, only the sealing surface of the end plate is brought into contact with a hot plate, or only the surface is heated and melted by irradiating an infrared heater, and one end surface of the pleated body is pressed against the melting surface of the plate to perform adhesive sealing.

In the case of the solvent bonding method, it is important to select a solvent. Usually, a solvent that does not dissolve the filtration membrane or has low solubility in the filtration membrane and has solubility in the end plate is selected. The solvent may be one kind of solvent or a mixed solvent. When mixing two or more solvents, it is preferable to select a solvent having at least a higher boiling point and having no solubility in the filtration membrane. More preferably, the polymer is dissolved in the solvent adhesive in an amount of about 1% to 7%. As the polymer to be dissolved, it is preferable to select the same material as the end plate or at least a material which easily adheres to the end plate.

The materials used for the core 5, the outer peripheral cover 1 and the end plate 6 must also have heat resistance and chemical resistance. If all or any one of the filtration membrane, membrane support, perimeter cover, core or end plate is a dissimilar material, chemical resistance is determined by the weakest material. For example, if a material that is weak to alkalis is used for the filtration membrane, a material that is weak to acid is used for the support material, and a material that is weak to organic solvent is used for the end plate, the resulting filter cartridge will be used for liquids other than water. No, it is very poor in chemical resistance. Therefore, it is preferable that the filtration membrane, the membrane support material, the outer peripheral cover, the core, and the end plate are all made of the same material. The same material is more preferable because of good adhesiveness.
When a PTFE filtration membrane is used, PFA (perfluoroalkoxylate) is most preferably used for the membrane support material, outer peripheral cover, core and end plate.

[0033]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Example 1 An ethanol bubble point of 250 kPa (AST) was obtained by the method described in Example 1 of JP-A-63-139930.
MF 316 test) to form a polysulfone membrane, which was used as a microporous filtration membrane. On the other hand, JP-A-63-13
A polysulfone membrane having an ethanol bubble point of 50 kPa was formed by the method described in Example 3 of 9930, and this was used as a secondary support. A groove having a groove width of about 0.15 mm, a gap between the grooves of 0.15 to 0.3 mm, and a depth of about 55 μm was formed on one surface of each of the microporous filtration membrane and the secondary membrane support by emboss calendering. . Next, the two films were overlapped so that the surfaces on which the grooves were not formed were in contact with each other, and pleating was performed by an ordinary method. The interval between the folds was 10.5 mm, the width of the membrane was 240 mm, and the membrane bundle folded at about 190 peaks was cut, formed into a cylinder, and heat-sealed by fitting the folds at both ends. Informing, the membrane bundle and the core are housed in a polysulfone outer cover with an outer diameter of 70 mm, and both ends are aligned to form a pleated body. The window size of the outer cover is 2m in the axial direction
m, 22 mm in the circumferential direction, and a wall of about 4 mm was provided between the windows (in both the circumferential direction and the axial direction). Irradiate an infrared heater to the surface of the end plate made by shaving from a polysulfone round bar, and heat the surface of the end plate to about 300 ° C.
Then, the end of the pleated body, which has been sufficiently preheated, is pressed against the pleated body to seal it. The other side of the pleated body was similarly sealed by welding the end plate to complete the filter cartridge. Udelpolysulfone P-3500 manufactured by Amoco Co. was used for the preparation of the filtration membrane and the membrane support. Udelpolysulfone P-1700 manufactured by Amoco Co. was used for preparing the outer peripheral cover, core and end plate.

(Comparative Example 1) The same microporous filtration membrane as used in Example 1, but not subjected to emboss calendering, was used for comparison. This filtration membrane was sandwiched between two polypropylene nonwoven fabrics (Shintex PS-106, manufactured by Mitsui Petrochemical, fiber size: 2 denier, basis weight: 30 g / m ² ), and pleated by a usual method. 10.5m
m, the film width is 240 mm). A pleated membrane bundle heat-sealed at the seam was wound around the same polysulfone core as in Example 1 and housed in a polysulfone outer peripheral cover to produce a cartridge filter of a comparative example. The maximum number of pleated peaks that could be accommodated in this cartridge filter was 155.

Example 2 Fluoropore FP-100 manufactured by Sumitomo Electric Industries, Ltd.
0 (hole diameter 10μm) and FP-010 (hole diameter 0.1μm) on each one side of the groove width of about 0.15mm, the gap between grooves 0.15 to 0.3m
A groove having a depth of about 40 μm was formed by emboss calendering. The two films were overlaid and pleated by a normal method. FP-010 with no groove of FP-1000
Overlap so that the grooved surface of the
The membrane bundle, which was 10.5 mm in width and 240 mm in width, was cut at about 210 peaks, cut into a cylinder, heat-sealed by fitting the folds at both ends. The membrane bundle and the PFA core were housed in a PFA outer peripheral cover having an outer diameter of 70 mm, and both ends were aligned to produce a pleated body. The window size of the outer peripheral cover was 2 mm in the axial direction and 22 mm in the circumferential direction, and a wall of about 4 mm was provided between the windows (in both the circumferential direction and the axial direction). An infrared heater is applied to the surface of the end plate, which is cut from a PFA round bar, and the surface of the end plate is heated to about 380 ° C to melt, and the end of the pleated body that has been sufficiently preheated is pressed against this to form an adhesive seal. gave.
The other side of the pleated body was similarly sealed by welding the end plate to complete the filter cartridge.

Example 3 Two embossed calendered membrane supports in Example 1 were prepared, one of which was used as a secondary support, and the surface of the membrane where grooves were not formed and the microporous filtration By superimposing so that the non-grooved surfaces of the membranes are in contact with each other, and arranging the other membrane support as the primary support with the non-grooved surface facing the filtration membrane side A microfiltration filter cartridge was manufactured in the same manner as in Example 1 except that a pleated body having a configuration in which two membrane supports and one filtration membrane were stacked therebetween was manufactured. This pleated body
About 170 pleats were able to be taken into the cartridge. This filtration membrane filter cartridge
Although the number of peaks / grooves is smaller than that of Example 1 in which one membrane support is used, the number of membrane supports is increased by one in comparison with a comparative example using a membrane support having no concave portion, groove, or convex portion. Regardless, a wider filtration area was obtained.

[0037]

As described above, in the pleated type microfiltration filter cartridge, the microporous filtration membrane has fine concave portions, structures and / or
Or, by the microfiltration filter cartridge of the present invention provided with a convex portion, or by the microfiltration filter cartridge of the present invention using one membrane support provided with irregularities or grooves in a microporous membrane or a perforated film, the built-in filtration membrane area And an inexpensive precision filter cartridge that can increase the filtration flow rate and maintain chemical resistance can be provided. In addition, by unifying all of the constituent members with a polysulfone-based polymer or a fluorine-based resin, heat resistance and chemical resistance can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a developed view showing the structure of a pleated filter cartridge having a general structure and used in the present invention.

FIG. 2 is a developed view showing a structure of a pleated filter cartridge particularly preferred in the present invention.

[Explanation of symbols]

 1. Peripheral cover 2. 2. membrane support Microfiltration membrane 4. 4. Membrane support Cores 6a, 6b. End plate 7. Gasket 8. Liquid outlet

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4D006 GA07 HA74 HA91 JA02C JA03A JA03B JA03C JA10A JA10B JA10C JA19B JA19C JA22C JA27C JB07 MA03 MA22 MA24 MA31 MB09 MB11 MB12 MB15 MB16 MB20 MC17 MC22 MC23 MC29 MC30X MC54 MC62B MC63 PA01 PC01 PC11 PC12 PC41 PC45

Claims (5)

[Claims] 1. A pleated filter cartridge for microfiltration comprising a microporous filtration membrane, a membrane support, a core, an outer peripheral cover and two end plates, wherein the microporous filtration membrane has fine recesses, grooves, and the like. Alternatively, a microfiltration filter cartridge having a large number of convex portions. 2. A pleated microfiltration filter cartridge comprising a microporous filtration membrane, a membrane support, a core, an outer peripheral cover and two end plates, wherein the membrane support has fine recesses, grooves and / or projections. Is a film in which a large number of fine pores or grooves and / or convex portions are formed by forming a large number of holes, and a microporous filtration membrane is formed on either the primary side or the secondary side. A microfiltration filter cartridge that uses only one membrane support. 3. The microfiltration filter cartridge according to claim 2, wherein the microporous filtration membrane has a large number of fine recesses, grooves and / or protrusions. 4. A microporous filtration membrane and a membrane support constituting a filter cartridge are made of polytetrafluoroethylene resin (PTFE), and a core, an outer cover and an end plate are made of tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer. The precision according to any one of claims 1 to 3, wherein the resin is made of one or both of a coalescing resin (PFA) and a tetrafluoroethylene / hexafluoropropylene copolymer resin (PEP). Filtration filter cartridge. 5. The filter cartridge according to claim 1, wherein all of the microporous filtration membrane, the membrane support, the core, the outer peripheral cover, and the end plate constituting the filter cartridge are made of a polysulfone-based polymer. 2. The microfiltration filter cartridge according to claim 1.