JP4489545B2 - Filter element and filter cartridge using the same - Google Patents

Description

  The present invention relates to a filter element of a type including a pleated filter material formed by folding a thin film filter into a cylindrical shape and a highly rigid support that supports one or both of the inner and outer surfaces. The present invention relates to a filter element in which one or both of the supports are made of a porous material having rigidity. The filter element is housed in a housing with appropriate fluid inlets and fluid outlets to form a disposable or replaceable filter cartridge.

  The conventional filter element includes a cylindrical filter material, a resin-made inner cylindrical support member that supports the inner periphery of the filter material and has a large number of openings, and a resin-made material that supports the outer periphery of the filter material and has a large number of openings. It comprises an outer cylindrical support member, a cylindrical filter material, an inner cylinder, and a resin cap portion that seals the upper and lower ends of the outer cylinder. These structures are described in JP-A-5-111622. As the cylindrical filter material, a so-called pleated filter material which is bent into a pleat shape and sealed on both side edges is typically used.

  FIG. 1 shows an example of a conventional filter cartridge, which comprises a filter element 1 and a housing 13 for housing it. The filter element 1 includes a cylindrical pleated filter material 3 obtained by folding a thin film separation film into an accordion pleat shape, a resin inner cylinder 5 having a large number of openings 27 supporting the inner periphery of the filter material, and a number of filter materials supporting the outer periphery of the filter material. The resin outer cylinder 7 having the opening 25, the cylindrical filter material 3, the inner cylinder 5, and the resin caps 9 and 11 for sealing the upper and lower ends of the outer cylinder 7 are provided.

The housing 13 is, for example, one in which the upper housing portion 15 and the lower housing portion 17 are hermetically welded at the welding portion 19 after the filter element 1 is assembled. An inlet 21 for the liquid to be processed and an outlet 33 for the filtrate are formed at the lower end of the housing, and the liquid to be processed is formed between the inlet 21 and the outer peripheral surface of the filter element 1 and the inner wall of the housing 13 in order from the pump. The flow passes through the opening 25 of the outer cylinder 7 and is filtered by the cylindrical filter material 3, and the filtrate passes through the opening 27 of the inner cylinder 5. It enters the passage 29 and then flows out as a purified liquid from the outlet 33 through the outlet passage 31.
The upper cap 9 of the filter element 1 is provided with an annular wall 41 projecting upward, which fits into a sleeve 45 constituting the lower part of the gas vent on the housing 13 side and is hermetically held by an O-ring 43. ing. A secondary gas vent port 39 projects upward from the housing 13 through a passage 53. A primary gas vent 35 is also provided at the upper end of the primary passage.
The lower cap 11 of the filter element 1 is provided with an annular wall 47 protruding downward, which is fitted to the sleeve 51 on the housing 13 side and is hermetically held by an O-ring 49.
However, since both surfaces of the cylindrical filter material 3 are directly supported in contact with inner and outer cylinders having a large number of openings, the flow path of the fluid to be filtered is limited to the portions of the openings 25 and 27, and regions other than the openings Then, the flow to the filter material 3 does not spread sufficiently, the use efficiency of the filter material is limited, and if the clogging of the filter material around the opening progresses, the flow to the other part of the filter material will decrease more and more. There is a problem that the efficiency is lowered and the cartridge needs to be discarded or the filter element 1 needs to be replaced even if usable parts remain.

  In addition, as a filter cartridge that uses a combination of a primary filter (prefilter) membrane and a secondary filter membrane, a filter material with a prefilter function in which the primary filter membrane and the secondary filter membrane are overlapped and folded into an accordion pleat shape is known. However, since it is necessary to support the filter with a prefilter function by the inner cylindrical support member (core) and / or the outer cylindrical support member (cage) having a large number of openings, the filter can be folded per cartridge. As the membrane area decreases, the effective filtration area decreases, leading to an increase in filter pressure loss.

  On the other hand, in Japanese Utility Model Laid-Open No. 2-40409, as a filter element to be inserted into a cleaning cartridge for a bath, a secondary filter membrane which is fold-folded is supported on the peripheral surface of a perforated cylinder, and further, a part of the outer peripheral surface is supported. A material in which a primary filter medium such as a nonwoven fabric, a sponge sheet, or a metal mesh having a flow resistance lower than that of the secondary filter membrane is wound is described. In the initial stage of use, preferential filtration is performed through the portion where the primary filter medium and the secondary filter membrane overlap, and when clogging progresses, the liquid is directly applied to the secondary filter medium immediately below the primary filter medium from the portion where the secondary filter membrane is exposed. It is described that the flow rate increases the utilization rate of the secondary filter medium and increases the amount of filtration. However, in this configuration, a step of winding the primary filter medium around the secondary filter membrane is required, and the assembly work takes time.

JP-A-5-111622 Japanese Utility Model Publication No. 2-40409

In the conventional filter element of Patent Document 1 or a filter cartridge using the same, a sufficient cylindrical filter material is directly supported in contact with the inner cylinder or the outer cylinder having a large number of openings as described above. The flow path of the fluid to be filtered is limited to the portion of the opening, and the flow to the filter material is not sufficiently distributed in a region other than the opening, so that there is a problem that the actual utilization efficiency of the filter material is limited.
In the above conventional example in which the primary filter membrane and the secondary filter membrane are overlapped and folded, there is a problem that the effective filtration area is reduced.
In the filter element described in Patent Document 2 or a filter cartridge using the filter element, a step of winding the primary filter medium around the secondary filter medium is necessary, and there is a problem that time is required for assembly work.
Further, due to the pressure of the fluid loaded on the opening of the conventional cylindrical filter material, a part of the pleated filter material is pressed against the corner of the opening of the inner cylindrical filter material, and is damaged at once. There also arises a problem that the filtration efficiency is lowered.
It is an object of the present invention to provide a filter element that is easy to assemble, has a long service life, and has high utilization efficiency.

(1) The present invention relates to a pleated filter material formed by folding a thin film filter into a cylindrical shape, and a rigid and porous cylindrical plate filter that supports an upstream peripheral surface of the pleated filter material. And a filter material made of a porous cylindrical plate filter having a large number of openings and having rigidity, which supports a downstream peripheral surface of the pleated filter material.
(2) In another preferred embodiment of the present invention, the thin film filter is folded and has a cylindrical pleated filter material, and a plurality of openings supporting the upstream peripheral surface of the pleated filter material and A filter material comprising a porous cylindrical plate filter having rigidity;
Provided is a filter element constituted by a filter material made of a rigid and porous cylindrical plate filter that supports a downstream peripheral surface of the pleated filter material.
(3) In another preferred embodiment of the present invention, the thin film filter is folded and has a cylindrical pleated filter material, and a plurality of openings for supporting the upstream peripheral surface of the pleated filter material, and A filter material comprising a porous cylindrical plate filter having rigidity;
There is provided a filter element constituted by a filter material made of a porous cylindrical plate filter having a large number of openings and supporting rigidity, which supports a peripheral surface on the downstream side of the pleated filter material.
(4) In still another preferred embodiment of the present invention, the thin film filter is folded and a cylindrical pleated filter material is provided, and a plurality of openings are provided to support the upstream peripheral surface of the pleated filter material. And a non-porous cylindrical plate filter having a large number of openings and supporting a filter material comprising a rigid porous cylindrical plate filter and a downstream peripheral surface of the pleated filter material. The filter element comprised with the filter material which becomes.
(5) In another preferred embodiment of the present invention, the thin film filter is folded and has a cylindrical pleated filter material, and a plurality of openings for supporting the upstream peripheral surface of the pleated filter material and A filter material composed of a rigid non-porous cylindrical plate filter, and a porous cylindrical plate filter having a large number of openings and supporting rigidity around the downstream surface of the pleated filter material. A filter element comprising a filter material is provided.
(6) In another embodiment, in (1) above, the downstream surface of the filter material that supports the upstream peripheral surface of the pleated filter material has an average pore diameter smaller than the hole diameter of the upstream filter material. Still another filter material having the following is provided .
(7) In another preferred embodiment of the present invention, in each of (1) to (5), each of the porous cylindrical plate filters is a cylindrical plate filter having an average pore diameter of 5-500 μm or a rigid nonwoven fabric. To do.
(8) In another preferred embodiment of the present invention, in the above (1) to (5), each of the porous cylindrical plate filters is configured using a polyethylene plate filter having an average pore diameter of 20 to 500 μm. The pleated filter is made of polyethylene and is suitable for purifying a polymer having a viscosity of 1000 cps (centipoise) to tens of thousands of cps.
(9) In a preferred embodiment of the present invention, in each of the above (1) to (5), each porous cylindrical plate filter is configured using a fluororesin plate filter having an average pore diameter of 10 to 500 μm, and the pleated filter Is used in a step of peeling a photoresist using a chemical solution, which is made of polytetrafluoroethylene having a pore diameter of 0.05 μm to 0.2 μm.
(10) The present invention further relates to the housing according to (1) to (9), in which the filter element is accommodated, wherein the inlet of the supply liquid, the outlet of the filtrate, and the inlet are located upstream of the filter element. There is provided a filter cartridge having a supply flow path, a flow path coupled to the downstream side of the filter element, and means for airtightly dividing the upstream side and the downstream side of the filter element.
In the present invention, the opening of the porous cylindrical plate filter having upstream and downstream rigidity has a size such that the liquid flow is concentrated as compared with the porous portion.

According to the present invention, the following effects can be obtained.
(1) Pre-filter function A pleated filter made of a filter membrane having an appropriate pore size is formed by a cylindrical body made of a plate filter having an appropriate pore size (pore size), which constitutes an inner or outer filter material on the supply side of the liquid to be treated. By combining with a material, the inner or outer filter material can have a prefilter function.
In the filter material with a pre-filter function in which the conventional primary (pre) filter membrane and secondary filter membrane are overlapped and folded into an accordion pleat shape, the area of the filter membrane that can be folded per cartridge is reduced, so the effective filtration area The pressure loss of the filter decreases and causes an increase in the pressure loss of the filter, but at least the upstream side of the inner and outer cylindrical filter material has rigidity and a porous plate filter so that it has a function as a prefilter. Therefore, the effective filtration area is not reduced.
(2) Expansion of membrane effective filtration area In the conventional filter, the fluid passes through the pleat filter material after passing through a large number of openings in the upstream cylindrical support member (cage). The pleated filter material portion that is intensively loaded with foreign matter and does not overlap the opening does not function effectively. This phenomenon is particularly noticeable when the size of the foreign matter is large or when the foreign matter concentration is high. When foreign substances are intensively applied to a part of the pleated filter material, the particle removal performance is deteriorated or the flow rate characteristic is deteriorated quickly. By using a porous cylindrical filter material having rigidity, it becomes possible to disperse the flow of the fluid, and to effectively function the entire pleated filter material.
(3) Increasing filter strength Conventional filters have high flow filtration or high viscosity because fluid concentrates through the opening of the upstream cylindrical support member or the opening of the downstream cylindrical support member. In the filtration of fluid, stress concentrates on a part of the pleated filter material that is weak, and the pleated filter material may be damaged or deformed. Since the rigid and porous cylindrical filter material disperses the flow of fluid, the stress applied to the pleated filter material is also dispersed, which is effective in preventing damage to the pleated filter material. The same effect can be obtained even when a porous cylindrical filter material having rigidity having a large number of openings is used. When a non-woven fabric or the like is wound around a pleated filter material as in Patent Document 2, a squeezing stress is applied to the pleated filter material, it is deformed by the pressure of the supply fluid, and squeezing occurs to inhibit fluid flow. However, the present invention does not have such a problem.
(4) Suppression of pressure loss increase at high flow rate Under high flow rate, the inner and / or outer cylindrical support members having a large number of openings cause turbulent flow due to the concentration of fluid in the openings, and the pressure of the filter This will increase the loss. The rigid and porous inner and / or outer cylindrical filter material, in a form that does not have a large number of openings, makes fluid movement laminar and suppresses an increase in the pressure loss of the filter. In addition, a porous inner and / or outer cylindrical filter material having a large number of openings has a function of distributing the fluid to the porous portion, so that the movement of the fluid suppresses an increase in pressure loss in the pleated filter material. There is.
(5) Ease of assembly The rigid and porous inner and / or outer cylindrical filter material is easy to handle and can easily assemble the cartridge. It is not easy to wind a non-woven fabric or the like around the pleated filter material, and the process takes time and is expensive.

  The filter element of the present invention and the material of the filter cartridge incorporating the filter element are all known except for the inner and outer cylindrical plate filters. For example, the material of each member is described in detail in JP-A-5-111622 cited above.

  As the rigid and porous inner and outer cylindrical plate filter used in the filter element of the present invention, a granular material of an appropriate resin such as polyethylene, polypropylene, PVC, Teflon is selected, and a cylinder having a desired thickness and shape. An open-cell porous body can be used by inserting into a mold having a shaped molding cavity and then increasing the softening temperature of the resin to weld only the contact points on the particle surface to each other. Such a plate filter can be selected from various plate filters such as Sun Fine AQ of Asahi Kasei Co., Ltd., Fildas of Mitsubishi Plastics Co., Ltd., and a plastic filter of Freon Industries Co., Ltd.

  The stiffness of the plate filter may be arbitrary as long as it has sufficient strength to replace a conventional non-porous support having a large number of openings. Various materials and pore sizes can be selected depending on the application. For example, when gel particles and coarse particles are present in the liquid to be treated, they should be separated, and a plate filter having a material and a hole diameter selected in association with the material and the hole diameter of the pleated filter material is used. On the other hand, in the case of a non-porous support, in order to alleviate the concentration of the flow at the opening and disperse the fluid throughout the filter membrane, a large number of openings may be provided in the inner and / or outer cylindrical filter material. good.

  In the filter element of the present invention, a rigid and porous cylindrical filter material is disposed at least upstream of the pleated filter material. Another cylindrical filter material having the same rigidity and being porous may be used on the downstream side of the pleated filter material, or may be supported by a cylindrical support member having an opening as in the conventional case. Furthermore, the porous cylindrical filter material having rigidity according to the purpose may be provided with a large number of openings. Any of the rigid and porous inner and outer cylindrical filter materials may be on the upstream side, but generally the outer cylindrical filter material is on the supply side of the liquid to be treated.

The pore diameter of the porous cylindrical plate filter can vary depending on the application. For example, in filtration of photosensitive polyimide or non-photosensitive polyimide solution used as a semiconductor protective film, a polyethylene plate filter having an average pore diameter of 20 μm to 500 μm is suitable for the outer cylindrical support member and / or inner cylindrical support member. ing. In this case, an ultrahigh molecular weight polyethylene pleated filter material having an average pore diameter of 0.2 μm or less can be used as a filter material. The polyimide solution usually has a high viscosity of 1000 cps (centipoise) to tens of thousands cps, and a filtration pressure of several kg / cm ² is applied to the upstream side of the filter during filtration.

On the other hand, in the filtration of the photoresist stripping solution, the outer cylindrical support member is constituted by a fluororesin plate filter having an average pore diameter between 10 μm and 500 μm, and the inner diameter is 0.05 μm to 0.2 μm. A pleated filter material made of polytetrafluoroethylene having the above can be used.
In the step of stripping the photoresist adhering to the semiconductor wafer using a chemical solution without passing through the ashing step, the residue of the insolubilized photoresist having a size of several tens to several hundreds of μm is removed from the stripping solution. A large amount is released inside. In addition, a large foreign substance of several hundred μm cannot penetrate into the gap between the pleats of the microfiltration membrane and is concentrated and captured at the folds of the pleats, so that clogging is not only further accelerated, It also becomes a cause of causing the particle-removal performance deterioration early with the reduction of the effective filtration area of the microfiltration membrane. By using a plate filter having a hole diameter selected according to the size of the free photoresist residue for the outer cylindrical support member, the outer cylindrical support functions as a prefilter. It is held on the surface and inside of the cylindrical support. As a result, the time required for the filter to become clogged is extended.

Thus, the inner and outer porous inner and / or outer cylindrical plate-holding members are selected and used according to the purpose. In general, as a material for a plate filter suitable for such a purpose, an ultra-high molecular weight polyethylene having an average pore diameter of about 5-135 μm and an average porosity of 25-50% (“Fildas (trade name)” manufactured by Mitsubishi Plastics, Inc.) Surface-layer hydrophilic polyolefin resin having an average pore size of 20-40 μm and an average porosity of 35-50% (“Sunfine AQ (trade name)” manufactured by Asahi Kasei Co., Ltd., and other similar average pore sizes of polyethylene, polypropylene, poly Methyl methacrylate, PVC, ACS, PTFE (all of which are, for example, Freon Industries Co., Ltd.) can be used.
A highly rigid nonwoven fabric can also be referred to as a plate filter for the purposes of the present invention. For example, PTFE (manufactured by Daicel Corporation) having an average pore diameter of about 10 μm and an average porosity of 70 to 76% in a non-woven fabric form, and polypropylene (manufactured by Kuraray Co., Ltd., “Microflex” (trade name) having an average porosity of 88 to 93% ) "Etc. can also be used.
A porous inner and outer cylindrical plate support is formed using a cylindrical plate filter having an average pore diameter of about 5-500 μm and an average porosity of about 20-95% or a rigid nonwoven fabric.

  When these porous cylindrical supports are used on the upstream side, they not only make the distribution of the fluid uniform, but also act as a prefilter, capture coarse particles and prevent clogging of the precision filter material. On the other hand, when it is used on the downstream side, the filtrate is collected smoothly, and effective use of the entire filter material is achieved.

Example 1
With reference to FIG. 2, an example of using a rigid and porous cylindrical inner filter material and a rigid and porous outer filter material will be described. In the figure, members similar to those in FIG. 1 are denoted by the same reference numerals.
The filter cartridge includes a filter element 1 and a housing 13 that houses the filter element 1. The filter element 1 includes a cylindrical pleated filter material 3 formed by bending a porous separation membrane into an accordion pleat shape, and an inner filter material 65 comprising a rigid and porous cylindrical plate filter that supports the inner periphery of the filter material. And an outer filter material 67 made of a rigid and porous cylindrical plate filter that supports the outer periphery of the pleated filter material 3, and upper and lower ends of the cylindrical pleated filter material 3, the inner filter material 65, and the outer filter material 67. And resin caps 9 and 11 for sealing the portions.
The outer filter material 67 has a hole diameter larger than the hole diameter (pore size) of the pleated filter material 3 so as to function as a prefilter, or has a different property from that of the pleated filter material 3 so as to have a different filtering function. It can consist of resin. The inner filter material 65 for passing the filtrate has a hole diameter larger than that of the pleated filter material 3 so as to sufficiently reduce the flow resistance, or different from the pleated filter material 3 so as to have a different filtering function. It can be composed of a resin of the nature.
In some cases, the inner filter member 65 does not require a filtering function so much, and the inner cylinder 5 which is the same as the conventional one can also be used.

The housing 13 is, for example, one in which the upper housing portion 15 and the lower housing portion 17 are hermetically welded at the welding portion 19 after the filter element 1 is assembled. An inlet 21 for the liquid to be processed and an outlet 33 for the filtrate are formed at the lower end of the housing, and the liquid to be processed is formed between the inlet 21 and the outer peripheral surface of the filter element 1 and the inner wall of the housing 13 in order from the pump. The flow passes through the annular primary side flow path 23, is distributed, passes through the outer cylindrical filter material 67, and is filtered by the cylindrical pleated filter material 3, and the filtrate passes through the inner cylindrical filter material 65, and the secondary water in the center. It enters the side channel 29 and then flows out from the outlet 33 through the outlet channel 31 as a purified liquid.
The upper cap 9 of the filter element 1 is provided with an annular wall 41 projecting upward, which fits into a sleeve 45 constituting the lower part of the gas vent on the housing 13 side and is hermetically held by an O-ring 43. ing. A secondary gas vent port 39 projects upward from the housing 13 through a passage 53. A primary gas vent 35 is also provided at the upper end of the primary passage.
The lower cap 11 of the filter element 1 is provided with an annular wall 47 protruding downward, which is fitted to the sleeve 51 on the housing 13 side and is hermetically held by an O-ring 49.
In this example, since the inner and outer filter members 65 and 67 have both a filtering function and a supporting function, a conventional cylindrical supporting member having a large number of openings is not necessary, and the flow is changed to a pleated filter material. It becomes possible to distribute uniformly, and it is possible to improve the filtration area and reduce the size of the filter cartridge. Further, the outer filter material 65 functions as a pre-filter, and the inner filter material 67 can function as a post filter material.
Further, in assembling the filter element, a pleated filter material folded in a cylindrical shape is fitted around the cylindrical inner filter material 65, and a cylindrical outer filter material 67 is fitted around the pleated filter material. The caps 9 and 11 need only be welded and hermetically sealed, which facilitates assembly.

Example 2
FIG. 3 shows another embodiment of the present invention. This example differs from Example 1 in that the rigid and porous material having a large number of openings 66 and 68 is used instead of the rigid and porous inner filter material 65 and outer filter material 67 shown in FIG. This is a point that the inner filter material 65a and the outer filter material 67a are replaced. In this example, the concentration of the processing liquid in the opening 68 of the outer filter material 67a is reduced, and the concentration of the filtrate in the opening 66 of the inner filter material 65a is also reduced, and the processing liquid is distributed to the pleated filter material 3 almost uniformly. Therefore, the effective filtration area increases. The outer filter material 65a can function as a pre-filter, and the inner filter material 67a can function as a post filter material.

Example 3
FIG. 4 shows still another embodiment of the present invention. In general, fine particles and coarse particles are mixed in the feed liquid to be filtered, so in the example using a single outer filter as shown in FIG. 2, clogging occurs relatively quickly, and flow resistance increases. Filtration efficiency decreases. Therefore, in this embodiment, instead of the single outer filter material 67 of FIG. 2, the upstream side is constituted by a cylindrical filter material 67b having a relatively large average pore diameter, and the downstream side is constituted by a fine cylindrical filter material 67c. The outer filter material is used. Both of the filter materials 67b and 67c may be composed of an integral asymmetric single filter material, or may be a composite filter material in which two filter materials are superimposed.

Variations The following are also included in the present invention as variations of the present invention depending on the purpose of filtration.
1) In the embodiment shown in FIGS. 2 and 4, instead of the inner filter member 65, a porous inner filter member 65a having a large number of openings shown in FIG.
2) In the embodiment shown in FIGS. 2, 3, and 4, a conventional cylindrical support member having a large number of openings is used instead of the inner filter members 65 and 65a.
3) In the embodiment of FIG. 3, instead of the inner filter material 65a, the porous inner filter material 65 having rigidity shown in FIG. 2 is used.
4) In the embodiment of FIG. 3, the average pore diameter of the outer filter material 67a is selected from a relatively large one, and the outer filter material 67a is made of a porous cylindrical filter material having no opening on the inner surface and having a smaller average pore diameter.
When the processing liquid supply passage and the filtrate discharge passage are opposite to those in FIGS. 2 to 4, the above relationship needs to be reversed.

  As described above, according to the present invention, the effects described in detail in the column of the effect of the invention can be obtained.

Example 1
Filtration of high-viscosity polyimide To show an example of purification of high-viscosity polyimide using the filter element of Example 1, the outer cylindrical support member and the inner cylindrical support member have an average pore diameter between 20 μm and 500 μm. A cartridge filter constituted by using a polyethylene plate filter, in which an ultrahigh molecular weight polyethylene pleated filter material having a pore diameter of 0.2 μm is installed between both cylindrical supports, is a photosensitive polyimide used as a semiconductor protective film or Used for filtration of non-photosensitive polyimide. Polyimide used as a semiconductor protective film usually has a high viscosity of 1000 cps (centipoise) to tens of thousands cps, and in the filtration performed when a polyimide is filled in a bottle, several kg are placed on the upstream side of the filter. A filtration pressure of / cm ² is applied. In a conventional filter cartridge in which a cylinder having a large number of openings is used as an outer support and an inner support, stress is concentrated at the openings of the support when high-viscosity chemicals pass through the filter. The microfiltration membrane located in the opening of the body may be damaged during use, and the filtration accuracy may be significantly reduced.
Since the outer and inner cylindrical supports made of porous plate filters disperse the flow of the high-viscosity chemical solution, stress is not concentrated on a part of the microfiltration membrane. As a result, the strength of the filter cartridge is improved, and it is possible to prevent the microfiltration membrane from being damaged when the high viscosity chemical solution represented by polyimide is being filtered.

Example 2
Filtration of photoresist stripping solution The outer cylindrical support member is composed of a fluororesin plate filter having an average pore diameter of 10 μm to 500 μm, and a polytetrahedral having a pore diameter of 0.05 μm to 0.2 μm inside thereof. A cartridge filter provided with a microfiltration membrane made of a fluoroethylene pleated filter material or a housing-integrated filter is used for circulating filtration of chemicals in the process of peeling the photoresist from the semiconductor wafer.
In the step of stripping the photoresist adhering to the semiconductor wafer using a chemical solution without passing through the ashing step, the residue of the insolubilized photoresist having a size of several tens to several hundreds of μm is removed from the stripping solution. A large amount is released inside. The filter used for filtration of the stripping solution is often required to have a particle removal performance that removes fine particles of 0.2 μm or less, but foreign substances having a size significantly exceeding the pore size of the microfiltration membrane are contained in the chemical solution. Because of the coexistence in large quantities, filter clogging occurs early. In addition, a large foreign substance of several hundred μm cannot penetrate into the gap between the pleats of the microfiltration membrane and is concentrated and captured at the folds of the pleats, so that clogging is not only further accelerated, It also becomes a cause of causing the particle-removal performance deterioration early with the reduction of the effective filtration area of the microfiltration membrane.
By using a plate filter having a hole diameter selected according to the size of the free photoresist residue for the outer cylindrical support member, the outer cylindrical support functions as a prefilter. It is held on the surface and inside of the cylindrical support. As a result, the time required for the filter to become clogged is extended.
In addition, the microfiltration membrane folded in pleats is loaded only with relatively small foreign substances that can enter the gap between the pleats, and the entire microfiltration membrane functions effectively. Extension is possible.

It is sectional drawing which shows the typical example of the filter cartridge incorporating the conventional filter element. It is sectional drawing which shows the typical example of the filter cartridge incorporating the filter element by Example 1 of this invention. It is sectional drawing which shows the typical example of the filter cartridge incorporating the filter element by Example 2 of this invention. It is sectional drawing which shows the example of the filter cartridge incorporating the filter element by the multilayer filter material by Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Filter element 3 Cylindrical pleat filter material 9, 11 Resin cap 13 Housing 15 Upper housing part 17 Lower housing part 19 Welding part 21 Inlet to be processed 23 Annular primary side flow path 33 Outlet of filtrate 29 Secondary Side channel 31 Outlet channel 35 Primary side gas vent port 39 Secondary side gas vent port 41 Annular wall 45 Sleeve 47 Annular wall 49 O-ring 51 Sleeve 65 Rigid and porous cylindrical inner filter material 65a With multiple openings Porous cylindrical inner filter material having high rigidity
66, 68 Opening 67 Rigid and porous cylindrical outer filter material 67a Porous cylindrical outer filter material having a large number of openings and rigidity 67b Rigid and porous cylindrical outer filter with large average pore diameter Filter material 67c Cylindrical outer filter material having rigidity and being porous and having a small average pore diameter

Claims (10)

A pleated filter material which is formed by folding a thin film filter into a cylindrical shape;
A filter material comprising a rigid and porous cylindrical plate filter that supports the upstream peripheral surface of the pleated filter material;
A filter element comprising a porous cylindrical plate filter having a large number of openings and having rigidity, supporting a peripheral surface on the downstream side of the pleated filter material. A pleated filter material which is formed by folding a thin film filter into a cylindrical shape;
A filter material comprising a porous cylindrical plate filter having a large number of openings and supporting rigidity, supporting the upstream peripheral surface of the pleated filter material;
A filter element constituted by a filter material made of a rigid and porous cylindrical plate filter that supports a downstream peripheral surface of the pleated filter material. A pleated filter material which is formed by folding a thin film filter into a cylindrical shape;
A filter material comprising a porous cylindrical plate filter having a large number of openings and supporting rigidity, supporting the upstream peripheral surface of the pleated filter material;
A filter element comprising a porous cylindrical plate filter having a large number of openings and having rigidity, supporting a peripheral surface on the downstream side of the pleated filter material. A pleated filter material which is formed by folding a thin film filter into a cylindrical shape;
A filter material comprising a porous cylindrical plate filter having a large number of openings and supporting rigidity, supporting the upstream peripheral surface of the pleated filter material;
A filter element comprising a non-porous cylindrical plate filter having a large number of openings and having rigidity, which supports a peripheral surface on the downstream side of the pleated filter material. A pleated filter material which is formed by folding a thin film filter into a cylindrical shape;
A filter material comprising a non-porous cylindrical plate filter having a plurality of openings and having rigidity, supporting an upstream peripheral surface of the pleated filter material;
A filter element comprising a porous cylindrical plate filter having a large number of openings and having rigidity, supporting a peripheral surface on the downstream side of the pleated filter material. The downstream surface of the filter material that supports the upstream peripheral surface of the pleated filter material is further provided with another filter material having an average pore diameter smaller than the pore diameter of the upstream filter material. The filter element according to 1.   The filter element according to any one of claims 1 to 5, wherein each of the porous cylindrical plate filters is configured using a cylindrical plate filter having an average pore diameter of 5-500 µm or a rigid nonwoven fabric.   Each of the porous cylindrical plate filters is formed using a polyethylene plate filter having an average pore diameter of 20 to 500 μm, and the pleated filter is made of polyethylene and has a viscosity of 1000 cps (centipoise) to tens of thousands cps. 6. A filter element according to any one of claims 1 to 5 for polymer purification. Each of the porous cylindrical plate filters is composed of a fluororesin plate filter having an average pore diameter of 10 to 500 μm, and the pleated filter is composed of polytetrafluoroethylene having a pore diameter of 0.05 μm to 0.2 μm. The filter element as described in any one of Claims 1-5 used in the process of peeling the photoresist using a chemical | medical solution.   A housing housing the filter element according to any one of claims 1 to 9, wherein a supply liquid inlet, a filtrate outlet, and a flow path for supplying the inlet to the upstream side of the filter element; A filter cartridge comprising: a flow path coupled to the downstream side of the filter element; and means for airtightly dividing the upstream side and the downstream side of the filter element.

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