JP2002028457A - 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 has good pressure resistance. SOLUTION: A precision filtration filter cartridge is distinguished by that all of a micro-porous filter membrane, a membrane support, a core, an outer peripheral cover and an end plate constituting the filter cartridge are made of a polysulfone polymer and axial sizes of windows of the outer peripheral cover and the core are 1 to 3 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cartridge filter using a microporous filtration membrane. More specifically, the present invention relates to a cartridge filter using a hydrophilic microporous microfiltration membrane having excellent chemical resistance, which can be suitably used in the production process of semiconductors, pharmaceuticals and the like.

[0002]

2. Description of the Related Art In recent years, in the manufacture 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, a microporous microfiltration membrane made of polytetrafluoroethylene (PTFE) is used for filtering such a chemical solution, and a filtration filter using a fluoropolymer is used for other filter components. ing. However, the PTFE filtration membrane has extremely strong hydrophobicity, so that even if it is wetted with isopropanol at the beginning of the filtration, it becomes impossible to perform the filtration due to the air lock caused by a small amount of air bubbles. Further, in the disposal of used fluorine-based polymer filters, there is a problem that toxic gas is generated by incineration.

[0003]

Accordingly, the present invention relates to an acid, an alkali, an oxidizing agent or an alcohol frequently used in a semiconductor manufacturing process, a pharmaceutical manufacturing process and the like. It is resistant to high-temperature filtration of mixed liquid of isopropanol and isopropanol from 60 ° C to 80 ° C, and has excellent durability against filtration pressure fluctuation,
It is another object of the present invention to provide a filter cartridge that facilitates incineration of used filters.

[0004]

The objects of the present invention have been attained by the following inventions. (1) A microfiltration filter cartridge in which all of a microporous filtration membrane, a membrane support, a core, an outer peripheral cover and an end plate constituting a filter cartridge are made of a polysulfone-based polymer. The microfiltration filter cartridge, wherein is not less than 1 mm and not more than 3 mm. (2) The microfiltration filter cartridge according to the above (1), wherein the primary and / or secondary membrane support is a microporous membrane having a large number of fine concaves and / or convexes. . (3) The microfiltration filter according to the above (1) or (2), wherein the water bubble point of the microporous filtration membrane is 0.3 MPa or more and the water bubble point of the membrane support is 0.15 MPa or less. cartridge. (4) The above-mentioned (1), wherein the primary side and / or the secondary side membrane support is formed by physically forming holes in the polysulfone-based polymer film and forming a large number of fine concaves and / or convexes. ) The microfiltration filter cartridge according to any one of the items (3) to (3). (5) The membrane support is formed by forming a large number of fine concaves and / or convexes on the polysulfone-based polymer film,
(1) wherein the fine recesses communicate with each other to form fine grooves through which the liquid can flow in the surface direction.
The microfiltration filter cartridge according to any one of Items (1) to (4).

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, a filter cartridge has 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 plurality of flat plate filtration units. Cartridges are known. Examples of the structure of the pleated cartridge include, for example, JP-A-4-235722 and 10-6.
No. 6842. Regarding the structure of the flat plate laminated cartridge, see, for example, JP-A-63-80815 and JP-A-56-1.
Nos. 29016 and 58-98111. The microfiltration filter cartridge of the present invention is applicable to a pleat cartridge among these types.

Hereinafter, the structure of the pleated filter cartridge will be described with reference to the drawings. FIG. 1 is a developed view showing the entire structure of a general pleated microfiltration membrane cartridge filter. In the pleated filter cartridge of FIG. 1, the microporous filtration membrane 3 is folded while being sandwiched by two membrane supports 2 and 4, and is 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 microporous filtration membrane 3. The microporous filtration 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. Gasket or
It is not essential that the O-ring is made of a polysulfone-based material because the O-ring can be easily detached when it is disposed of. The filtered liquid is collected from a liquid collecting port of the core, and is discharged from a fluid outlet 8 provided at an end of the cylinder through a hollow portion of the core. Fluid outlets are provided at both ends of the cylinder, and fluid outlets are provided at only one end and one end is closed. In this pleated filter cartridge, if necessary, the flows of the liquid to be filtered and the filtrate are reversed, that is, the liquid to be filtered is supplied from the fluid outlet 8 to the inside of the filter cartridge, and from the inside of the filter cartridge. Filtration is performed by passing through the microporous filtration membrane 3, and the filtrate can be discharged to the outside of the 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.

The microporous filtration membrane 3 is preferably a membrane made of a polyethersulfone such as aromatic polyarylethersulfone or a halogen-free polymer such as polyolefin or polyamide. Above all, a hydrophilic film made of an aromatic polyaryl ether sulfone (hereinafter referred to as a polysulfone polymer) is preferable because of its excellent heat resistance and chemical resistance.

A typical chemical structure of the polysulfone polymer used in the present invention is shown by the following general formulas (I) to (III). The polysulfone-based polymer represented by the general formula (I) is marketed by Amoco under the trade name "Udel Polysulfone". On the other hand, the polyether sulfone represented by the general formula (II) is sold by Sumitomo Chemical Co., Ltd. under the trade name of "SUMICA EXCEL PES".

[0009]

Embedded image

The microporous filtration membrane used in the microfiltration filter cartridge of the present invention uses a polysulfone-based polymer as a material, and appropriately selects a conventional method for producing a microporous filtration membrane.
It can be adopted and manufactured. As a method for producing a hydrophilic microporous microfiltration membrane made of a polysulfone-based polymer, JP-A-56-154051, JP-A-56-86941, JP-A-56-86941
These are described in detail in JP-A Nos. 12640, 62-27006, 62-258707, 63-141610, and the like.
There are various types of commercially available microporous microfiltration membranes composed of the polysulfone-based polymer, and commercially available products can be appropriately selected and used.

The pore size of the micropores of the microporous filtration membrane used in the present invention is usually from 0.02 μm to 5 μm, but when it is used for the production of semiconductors, it is preferably from 0.02 μm to 0.45 μm. 0.02μm to 0.2 in high integrated IC manufacturing
μm is preferred. ASTM F316
When expressed in terms of the water bubble point value measured by the method described above, it is 0.3 MPa or more, and the ethanol bubble point is 0.1 to 1 MPa.
Can be expressed as Particularly preferably at the ethanol bubble point
0.3 to 0.7 MPa. In addition, in the microporous filtration membrane, it is preferable that the ratio of the pores to the apparent volume is large because the filtration resistance is small. If the pores are too large, the membrane strength is reduced and the membrane is easily broken. Therefore, the porosity of the microporous filtration membrane is generally 40% to 90%, preferably 57% to 85%. The film thickness is usually 30 μm to 220 μm. If it is too thick, the film area that can be incorporated in the cartridge decreases, while if it is too thin, the film strength decreases. For this reason, the thickness of the microporous filtration membrane is generally suitable from 60 μm to 160 μm,
μm to 140 μm is preferred.

The microfiltration membrane 3 is sandwiched between the membrane supports 2 and 4 and is usually pleated by a known method. In a conventional pleated cartridge, a nonwoven fabric, a woven fabric, a net, a microporous membrane, or the like is used as the primary membrane support 2 and the secondary membrane support 4. 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 past, in most cases, a nonwoven fabric of polyester or polypropylene has been used because of its low cost and excellent performance.

However, the membrane support usable in the present invention needs to be a material which has both heat resistance and chemical resistance in addition to the above general functions and which can be incinerated.
Therefore, the present inventors have conducted various studies and found that for the above-mentioned purpose, it is preferable to use the same material as the microporous filtration membrane 3 or a halogen-free polymer having higher heat resistance and chemical resistance. It has been found that the system polymer has both heat resistance and chemical resistance and is particularly preferable. However, since a polysulfone-based polymer fiber has not been manufactured, a polysulfone-based polymer nonwoven fabric or woven fabric cannot be used.

For this reason, in the microfiltration cartridge filter of the present invention, a microporous membrane (not a woven or nonwoven fabric) made of a polysulfone-based polymer as a membrane support
Use The manufacturing method is basically the same as that of the microporous microfiltration membrane described above. The water bubble point of the microporous membrane used for the membrane support is generally 0.15 MPa or less, preferably
0.02MPa to 0.15MPa, more preferably from 0.04MPa
0.15MPa. The water permeability in the direction perpendicular to the membrane support surface is such that the water flow rate when a differential pressure of 0.1 MPa is applied per minute
150 ml / cm ² or more is preferable, and 200 ml / cm ² is more preferable.
That is all. Mullen burst strength of the membrane support is 80 kPa
It is preferably at least 120 kPa, more preferably at least 120 kPa.

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.
The interval between the concave portions and / or convex portions provided to the membrane support is 5
μm to 1 mm can be used, preferably 20 μm to 0.4 mm, more preferably 50 μm to 0.2 mm. 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. This is particularly preferred because the liquid can flow in the plane direction through the ridges or along the mountains.
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, more preferably in the range of 20 to 400 μm, and 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 from 60 μm to 3
00 μm is preferred, and 100 μm to 220 μm is more preferred. If it is too thin, the function of reinforcing the filtration membrane is inferior, and if it is too thick, the membrane area that can be incorporated into the cartridge is reduced, which is inconvenient.

In the present invention, grooves and ridges 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.

The thickness of the polymer film used for the membrane support is preferably 25 μm to 125 μm, particularly preferably 50 μm to 100 μm. If it is too thin, the function of reinforcing the filtration membrane is inferior, and if it is too thick, pleating becomes difficult.

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 cross sections of the polymer film include typical examples shown schematically in FIGS. 2A and 2B, and FIG.
Various shapes can be taken. In FIG. 2, reference numeral 9 denotes a polymer film, and illustration of physical holes formed in the polymer film is omitted.

The both sides of the microporous filtration membrane are sandwiched between membrane supports,
Pleat in this state in the usual way. At least one, and in some cases, a plurality of membranes can be used. At least one membrane support can be used on one side, and in some cases more than one membrane support can be used.

The pleated filter medium is trimmed at both ends with a cutter knife or the like in order to align both ends, rounded into a cylindrical shape, and the folds of the joint are heat-sealed or liquid-tightly sealed with an adhesive. . The adhesive seal may be performed by combining the microfiltration membrane and the membrane support in a total of 6 layers, or may be adhesively sealed so that the filter membranes directly overlap each other except for the support 2 or 4. The polysulfone sheet may be interposed between the folds and heat-sealed. As the adhesive or polysulfone sheet used here, the same material as the filtration membrane is preferable in order to improve the adhesiveness.
When an adhesive is used, the polysulfone-based polymer is used in a state of 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,
0 parts are gradually added and mixed. The solvent is heated and volatilized after bonding so that it does not remain in the filter cartridge.

The core filter 5 having the core 5 inserted inside the cylindrical filter medium thus formed and covered with the outer peripheral cover 1 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. The dimension of this slit-shaped window in the cylindrical axis direction is 1 mm or more, 3 mm or less, preferably 1.5 mm or more and 2 mm
It has been found that by performing the following, the function of protecting the outer peripheral cover against fluctuations in filtration pressure is significantly 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. In particular, when a filter cartridge having a large number of fine grooves and / or convex portions is used, the pressure resistance of the filter cartridge is dramatically improved. If the size of the window provided in the core is too small in the direction of the cylindrical axis, the liquid permeability is impaired. It is preferable that the gap between each window of the outer peripheral cover and the core be 2 mm or more and 20 mm or less in both the circumferential direction and the axial direction, since both strength and liquid permeability can be satisfied.
More preferably, it is 3 mm or more and 15 mm or less.

The end sealing step in which both end portions of the pleated body are liquid-tightly bonded and sealed to the end plate 6 can be roughly classified into a method based on heat melting and a method based on 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. More preferably, the polymer is dissolved in the solvent adhesive in an amount of about 1% to 7%. For the polymer to be dissolved, select the same material as the end plate or at least a material that easily adheres to the end plate.

The membrane supports 2, 4, the core 5, and the outer peripheral cover 1 used in the microfiltration filter cartridge of the present invention.
Also, the material used for the end plate 6 needs to have heat resistance and chemical resistance, and must be a material that can be easily incinerated. Accordingly, halogen-free polymer materials such as polysulfone-based polymers, polyolefins and polyamides are preferred. Among them, a polysulfone-based polymer material is preferable, and polyethersulfone is particularly preferable because it is excellent in heat resistance and chemical resistance and relatively inexpensive. The materials of the members need not necessarily be the same as long as they can be bonded to each other, but the same materials are more preferable because they have good adhesiveness. When all the materials are unified with polyether sulfone, the range of chemical resistance is widened, and it is particularly preferable in terms of adhesive sealability.

[0027]

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) Ethanol bubble point was measured using Sumica Excel PES (manufactured by Sumitomo Chemical Co., Ltd.) according to the method described in JP-A-63-139930.
A 250 kPa polyethersulfone membrane was formed and used as a microporous filtration membrane (referred to as membrane A). On the other hand, JP-A-63-13
A polyethersulfone membrane having an ethanol bubble point of 50 kPa was formed by the method described in Example 3 of Japanese Patent No. 9930. This film is called a B film. A groove having a groove width of about 0.15 mm, an interval between the grooves of 0.15 to 0.3 mm, and a depth of about 55 μm is formed on one surface of the B film by emboss calendering. This membrane C was used as a membrane support.

A pleating process was performed by a usual method with the film A interposed between the two films C. The surface of the film C in contact with the film A was a flat surface on which neither the primary film C nor the secondary film C had a groove. Pleated fold spacing is 10.5m
m, the membrane width was 240 mm, and the membrane bundle folded at about 170 peaks was cut, made cylindrical, and heat-sealed by fitting the folds at both ends. The membrane bundle and the polyethersulfone core were housed in a polyethersulfone outer peripheral cover, and both ends were aligned to produce a pleated body. Irradiate an infrared heater to the surface of the end plate made by cutting out a polyether sulfone round bar, heat the end plate surface to about 350 ° C, melt it, and press the end of the pleated body that has been sufficiently preheated to bond Sealed. The other side of the pleated body was similarly sealed by welding the end plate to complete the filter cartridge. The dimensions of the outer cover and the core window were 1.8 mm in the axial direction and 22 mm in the circumferential direction. cover,
Core and end plate are Sumika Excel PES3
Molded using 600G.

Comparative Example 1 A filter cartridge of Comparative Example 1 was produced in the same manner as in Example 1 except that the dimensions of the outer peripheral cover and the window of the core were 4 mm in the axial direction and 22 mm in the circumferential direction.

Example 2 A hole having a diameter of 0.6 mm was punched out of a polyethersulfone film (Sumilite FS-1300, manufactured by Sumitomo Bakelite Co., Ltd.) having a thickness of 50 μm at a ratio of 3 per 2 cm × 2 cm area. It was a perforated film. A soft resin roll was applied to the film as a back roll, and emboss calendering was performed so that the groove width was about 0.2 mm and the distance between the grooves was about 0.2 mm. The embossing conditions were as follows: embossing roll surface temperature 125 ° C, pressing 100 kN / m
Met.

Pleating was carried out by sandwiching a polyethersulfone microporous filtration membrane having a nominal pore diameter of 0.1 μm (Micro PES 1FPH manufactured by Membrana, ethanol bubble point value 340 kPa) between the two membrane supports thus produced. . The interval between the folds is 10.5 mm, the film width is 240 mm,
The membrane bundle folded at about 140 peaks was cut, made cylindrical, and heat-sealed by fitting the folds at both ends. A pleated body was assembled in the same manner as in Example 1, and the end plate was welded and sealed to produce a filter cartridge of Example 2.

(Comparative Example 2) A filter cartridge of Comparative Example 2 was produced in the same manner as in Example 2 except that the dimensions of the outer peripheral cover and the window of the core were 4 mm in the axial direction and 22 mm in the circumferential direction.

The filter cartridges of Examples 1 and 2 and Comparative Examples 1 and 2 produced as described above were subjected to the following tests. (1) Evaluation of Chemical Resistance The chemical resistance evaluation test was carried out by two methods using two kinds of chemicals, namely, hydrogen peroxide and isopropanol. The filter cartridge was immersed in each chemical and heated to 80 ° C. for 8 hours a day for a total of 480 hours, after which the integrity maintenance measurement and appearance observation of the filter cartridge were performed. The maintenance of the integrity was judged to be acceptable when the air pressure of 200 kPa was applied to the primary side of the filter cartridge, the supply of compressed air was shut off, and the air pressure did not decrease during standing for 3 minutes. Appearance observation was accepted when there was no change in the appearance of the new product before the test. Also,
Hydrochloric acid and hydrogen peroxide was used in a ratio of 1: 1 concentrated hydrochloric acid to 30% hydrogen peroxide and 1 to ultrapure water. Hydrochloric acid and hydrogen peroxide deteriorated. The above-mentioned chemical resistance test results of each of the filter cartridges of Examples 1 and 2 and Comparative Examples 1 and 2 were all within the acceptance criteria.

(2) Evaluation of pressure resistance The pressure resistance is determined by repeatedly supplying and discharging compressed air 200 times from the primary side and the secondary side of the filter cartridge which is wet with water and impervious to air. The test was conducted by measuring the integrity maintenance to evaluate whether or not the filter was broken. The applied air pressure was first increased by 100 kPa, then increased by 200 kPa in order of 100 kPa, and the applied air pressure was obtained by increasing the applied pressure until the integrity became poor. For the measurement of the maintenance of the integrity, the compressed air supply was shut off after applying the air pressure to the primary side of the filter cartridge, and a pass / fail judgment was made based on the presence or absence of a decrease in the air pressure during standing for 3 minutes. Table 1 shows the results of comparative measurement of the pressure resistance of the filter cartridges of Examples 1 and 2 and Comparative Examples 1 and 2. Examples 1 and 2 have excellent pressure resistance, whereas Comparative Examples 1 and 2 have poor integrity at low applied pressure.

[0036]

[Table 1]

[0037]

The microfiltration filter cartridge of the present invention is resistant to acids, alkali oxidizing agents and high-temperature alcohols and has excellent pressure resistance. Further, since the filter cartridge is constituted only by the polysulfone-based polymer member, the used filter cartridge can be easily incinerated without discharging toxic gas (containing halogen).

[Brief description of the drawings]

FIG. 1 is a development view showing a structure of a general pleated filter cartridge.

FIG. 2 is a schematic cross-sectional view showing an example of a cross section of an uneven shape of a film constituting a membrane support.

[Explanation of symbols]

 1. Peripheral cover 2. 2. Primary membrane support Microfiltration membrane 4. 4. Secondary membrane support Cores 6a, 6b. End plate 7. Gasket 8. Liquid outlet 9. Polymer film

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4D006 GA07 HA74 HA91 JA02B JA02C JA03A JA03B JA03C JA10B JA10C JA19B JA19C JA22C JA27C JB07 MA03 MA22 MA24 MA31 MB09 MB11 MB12 MB15 MB16 MB20 MC22 MC54 MC63X PA01 PB12 PB13 PB20 PC

Claims (5)

[Claims] 1. A microfiltration filter cartridge in which all of a microporous filtration membrane, a membrane support, a core, an outer peripheral cover and an end plate constituting a filter cartridge are made of a polysulfone-based polymer, and the outer cover and a core of a window of the core. A microfiltration filter cartridge having a directional dimension of 1 mm or more and 3 mm or less. 2. The microfiltration filter cartridge according to claim 1, wherein the primary and / or secondary membrane support is a microporous membrane formed with a large number of fine concaves and / or convexes. . 3. The water bubble point of the microporous filtration membrane is 0.3M.
Water bubble point of more than Pa and membrane support is 0.15MPa
The microfiltration filter cartridge according to claim 1, wherein: 4. The primary-side and / or secondary-side membrane support is formed by physically drilling holes in a polysulfone-based polymer film and forming a large number of fine concaves and / or convexes. Item 5. The microfiltration filter cartridge according to any one of Items 1 to 3. 5. A membrane support comprising a polysulfone-based polymer film having a large number of fine concaves and / or convexes formed thereon, and the fine concaves communicate with each other to form fine grooves through which a liquid can flow in a plane direction. The microfiltration filter cartridge according to any one of claims 1 to 4, wherein: