Hollow fiber membrane module, method for producing same, and method for producing ultrapure water using same

Abstract

[Problem] To provide: a hollow fiber membrane module capable of reducing the cleaning time at the beginning of use without affecting the water quality of ultrapure water to be produced; a method for producing the hollow fiber membrane module; and a method for producing ultrapure water using the hollow fiber membrane module. [Solution] A hollow fiber membrane module having a housing and a plurality of hollow fiber membranes housed in the housing, both ends of the hollow fiber membranes and both ends of the housing being fixed by a potting material, the hollow fiber membrane module is a filtering membrane module which is used for collecting filtered liquid from two ends of the shell and is provided with openings at two ends, and the amount of particles with the diameter of 50 nm or more in the filtering liquid obtained by performing external pressure filtering on treated water for 1 hour under the conditions that the water temperature is 25 DEG C and the permeation flux is 5 m / d by using the hollow fiber membrane module is 1 / mL or less.

Description

This application claims the priority of Japanese Patent Application No. 2023-200820 filed on November 28, 2023, the entire content of which is incorporated herein by reference in its entirety. Technical Field

[0001] The present invention relates to a hollow fiber membrane module suitable as a final filter for removing fine particles in water to be treated in an ultrapure water manufacturing process, a method for manufacturing the same, and a method for manufacturing ultrapure water using the hollow fiber membrane module. Background Art

[0002] In a production line for manufacturing water to be treated used in the manufacture of electronic / electrical components such as semiconductors and display elements, a filter membrane module is used as a final filter for removing fine particles from ultrapure water before supplying the water to be treated, which is manufactured using a microfiltration membrane, an ion exchange resin, and a reverse osmosis filtration membrane, to a point of use. As a filter membrane module for this purpose, an outside pressure filtration type hollow fiber membrane module in which raw water is supplied to the outside of the hollow fiber membrane for filtration is mainly used because it has the advantage of increasing the filtration flow rate per module.

[0003] As properties required for a filter membrane module for this purpose, it is required to bring the quality of ultrapure water, that is, the number of fine particles in the filtered water, the conductivity of the filtered water, and the content of organic matter TOC (total organic carbon) in the filtered water, etc., to the required level within a short time after the start of use. Therefore, generally, in a filter membrane module for this purpose, a washing process for reducing the generation of fine particles, ion components, and the elution of organic matter from the filter is set at the end of the manufacturing process of the product, and the product is put on the market in a state where it is washed until it reaches a clean state.

[0004] In addition, for a filter membrane module, in order to maintain its filtration performance and suppress the propagation of microorganisms in the product, it is necessary to use a preservative solution having a bactericidal and antibacterial effect after manufacturing, or to perform sterilization after enclosing water and store it in a wet state. For example, Patent Document 1 discloses enclosing water in a sterilized state at a high temperature as a preservative solution. The filter membrane module described in Patent Document 1 sterilizes the enclosed preservative solution, shortens the cleaning time of the filter membrane module, and thus efficiently produces ultrapure water. Prior Art Documents Patent Documents

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2018-089614 Summary of the Invention Problems to be Solved by the Invention

[0006] In an ultrapure water production line, the cleanliness of the hollow fiber membrane module must be maintained at a high level, that is, it is required that substances (such as particles, microorganisms, etc.) derived from the hollow fiber membrane do not affect the water quality of the produced ultrapure water. However, for example, although Patent Document 1 has studied the sterilization of the preservation solution, it has not studied improving the cleanliness of the filtration membrane module itself.

[0007] An object of one aspect of the present invention is to provide a hollow fiber membrane module, a manufacturing method thereof, and a method for manufacturing ultrapure water using the hollow fiber membrane module, which can shorten the cleaning time at the start of use and do not affect the water quality of the produced ultrapure water. Method for solving the problem

[0008] That is, the present invention satisfies the following aspects. <Aspect 1> A hollow fiber membrane module, wherein the hollow fiber membrane module has a housing and a plurality of hollow fiber membranes accommodated in the housing, both ends of the hollow fiber membranes and both ends of the housing are fixed by potting materials, the hollow fiber membrane module is an end-opened filtration membrane module for collecting the filtered liquid from both ends of the housing, and in the filtrate obtained by subjecting the water to be treated to external pressure filtration for 1 hour under the conditions of a water temperature of 25°C and a permeation flux of 5 m / d using the hollow fiber membrane module, the number of particles with a diameter of 50 nm or more is 1 particle / mL or less. <Aspect 2> The hollow fiber membrane module according to Aspect 1, wherein in the filtrate obtained by subjecting the water to be treated to external pressure filtration for 1 hour under the conditions of a water temperature of 25°C and a permeation flux of 5 m / d using the hollow fiber membrane module, the number of particles with a diameter of 20 nm or more is 3 particles / mL or less. <Aspect 3> A method for manufacturing the hollow fiber membrane module according to Aspect 1 or 2, the method comprising: a step of fixing both ends of a plurality of hollow fiber membranes and both ends of the housing with potting materials, and a cutting step of cutting the remaining portion of the potting material to open the hollow portions at both ends of the hollow fiber membranes, and the cutting step is a step of cutting using a diamond band saw. <Aspect 4> The method for manufacturing the hollow fiber membrane module according to Aspect 3, wherein the method further comprises a step of cleaning the hollow fiber membranes with pure water having a cleaning temperature of 50°C or higher after the cutting step. <Aspect 5> A method for manufacturing the hollow fiber membrane module according to Aspect 1 or 2, the method comprising: A step of fixing both ends of a plurality of hollow fiber membranes and both ends of a housing with a potting material, A cutting step of cutting the remaining part of the potting material to open the hollow portions at both ends of the hollow fiber membrane, and a step of cleaning the hollow fiber membrane with pure water at 50°C or higher after the cutting step. <Solution 6> The method for manufacturing a hollow fiber membrane module according to Solution 4, wherein the cleaning is a circulating cleaning in which the pure water is supplied from the outer surface of the hollow fiber membrane to the inner surface to permeate therethrough, the filtered water is recovered from both ends of the housing, and the recovered filtered water is supplied again to the outer surface of the hollow fiber membrane, and the permeation flux of the pure water is 5 m / d or more. <Solution 7> The method for manufacturing a hollow fiber membrane module according to any one of Solutions 4 to 6, wherein the cleaning temperature is 95°C or lower. <Solution 8> The method for manufacturing a hollow fiber membrane module according to Solution 3 or 4, wherein the circumferential speed of the diamond band saw is 10 to 1000 m / minute. <Solution 9> The method for manufacturing a hollow fiber membrane module according to Solution 3 or 4, wherein the circumferential speed of the diamond band saw is 300 to 500 m / minute. <Solution 10> The method for manufacturing a hollow fiber membrane module according to Solution 3 or 4, wherein when using the diamond band saw, the cutting surface is cooled by bringing water into contact with the cutting surface of the hollow fiber membrane in an amount of 0.5 L / minute or more. <Solution 11> A method for manufacturing ultrapure water, the method including removing fine particles in the water to be treated using the hollow fiber membrane module according to Solution 1 or 2. Advantages of the Invention

[0009] An object of the solution of the present invention is to provide a hollow fiber membrane module, a method for manufacturing the same, and a method for manufacturing ultrapure water using the hollow fiber membrane module, which can shorten the cleaning time at the start of use and do not affect the quality of the manufactured ultrapure water. BRIEF DESCRIPTION OF THE DRAWINGS

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0011] According to the manufacturing method of the hollow fiber membrane module of the present embodiment, the generation of dust from the potting material can be reduced in advance. In addition, according to the manufacturing method of the hollow fiber membrane module of the present embodiment, the flushing time of the hollow fiber membrane module at the start of use of the hollow fiber membrane module after the hollow fiber membrane module is installed in the ultrapure water production line can be significantly shortened, so that ultrapure water can be manufactured quickly.

[0012] If the hollow fiber membrane module of the present embodiment is used to manufacture ultrapure water, the yield in the semiconductor production process can be improved, and semiconductor products can be efficiently manufactured. Hereinafter, the hollow fiber membrane module of the present embodiment will be described with reference to the drawings.

[0013] <Hollow fiber membrane module> The hollow fiber membrane module of the present embodiment can be used in a filtration device for manufacturing ultrapure water. The hollow fiber membrane module of the present embodiment can be used for external pressure filtration before supplying ultrapure water manufactured using a microfiltration membrane, ion exchange resin, or reverse osmosis filtration membrane to the point of use, and can function as a final filter to remove fine particles. In addition, according to the hollow fiber membrane module of the present embodiment, since the generation of dust from the hollow fiber membrane module itself is suppressed, the ultrapure water production line can be started immediately when the ultrapure water production line is started or after the filter is replaced to start manufacturing ultrapure water. In addition, since unwanted substances such as fine particles are removed from the hollow fiber membrane module, the flushing operation of the hollow fiber membrane module at the ultrapure water manufacturing site can be shortened. According to the present embodiment, the time for cleaning unwanted substances such as organic matter (in one aspect, it is organic matter derived from the potting material, organic matter derived from the preservation liquid, and organic matter derived from the membrane-forming stock solution of the hollow fiber membrane), metal ions, and fine particles attached to the hollow fiber membrane at the start of use of the hollow fiber membrane module can be significantly shortened, and / or the mixing of the unwanted substances into the product (i.e., ultrapure water) can be suppressed.

[0014] The hollow fiber membrane module 1 of the present embodiment is as Figure 1As shown, there is a hollow fiber membrane bundle 3 formed by bundling a plurality of hollow fiber membranes 3a, and a cylindrical housing 5 that houses the hollow fiber membrane bundle 3. In one embodiment, the hollow fiber membrane module 1 is housed in a housing 5 having nozzles on its side. In one embodiment, there are multiple hollow fiber membranes inside the housing 5. In one embodiment, both ends of the hollow fiber membrane 3a and both ends of the housing 5 are fixed with potting material. In one embodiment, the hollow fiber membrane module 1 is an end-open filtration membrane module that collects the filtered liquid from both ends of the housing 5. In one embodiment, the housing 5 is filled with a sterilized liquid as a preservation liquid for maintaining the filtration performance of the hollow fiber membrane 3a.

[0015] At the openings at both ends of the housing 5, there are provided pipe connection top covers 10 and 11 formed with pipes 10a and 11a connected to the pipes. The pipe connection top covers 10 and 11 are fixedly installed on the housing 5 by nuts 13. The nuts 13 are screwed with the external threads formed on the sides at both ends of the housing 5. By tightening the nuts 13, the space between both ends of the housing and the top covers 10 and 11 is sealed by an O-ring 12 disposed in the grooves of the top covers 10 and 11.

[0016] In addition, upper nozzles 5a and lower nozzles 5b through which the fluid flows are respectively formed at both ends of the housing 5. The upper nozzles 5a and the lower nozzles 5b are provided to protrude in a direction orthogonal to the length direction of the housing 5.

[0017] On both end faces of the hollow fiber membrane bundle 3, the respective hollow fiber membranes 3a are open, and the respective hollow fiber membranes 3a are bonded by potting material to form a bonding portion 14.

[0018] In external pressure filtration, for example, the liquid flows in from the lower nozzle 5b. The liquid infiltrates from the outer surface of each hollow fiber membrane 3a between the bonding portions 14 at both ends, and the liquid after passing through the hollow portions of each hollow fiber membrane 3a flows out from the pipes 10a and 11a of the top covers 10 and 11.

[0019] As the hollow fiber membrane 3a, a microfiltration membrane, an ultrafiltration membrane, etc. can be used. For example, if the hollow fiber membrane module 1 is used for the final filter for ultrapure water, the hollow fiber membrane 3a is preferably an ultrafiltration membrane with a fractional molecular weight of 20,000 or less (more preferably 10,000 or less). There is no particular limitation on the material of the hollow fiber membrane 3a, and examples thereof include polyethylene, polypropylene, polysulfone, polyethersulfone, polyacrylonitrile, polyimide, polyetherimide, polyamide, polyether ketone, polyetherether ketone, polyethylene, polypropylene, poly-4-methylpentene, ethylene-vinyl alcohol copolymer, cellulose, cellulose acetate, polyvinylidene fluoride, polyvinyl alcohol, cellulose acetate, ethylene-tetrafluoroethylene copolymer, and polytetrafluoroethylene. In addition, composite materials thereof may also be used. As the materials of the hollow fiber membrane 3a and the housing 5, materials with less elution such as polysulfone-based materials are preferred.

[0020] The water permeation rate per single fiber in terms of the inner area of the hollow fiber membrane 3a at 25°C is preferably 100 L / m 2 / hr / 0.1 MPa (hereinafter, the unit of the water permeation rate per single fiber is denoted as "LMH") or more, and particularly preferably 200 LMH or more. The inner diameter of the hollow fiber membrane 3a is 50 μm to 3000 μm, preferably 200 μm to 2000 μm, more preferably 300 μm to 1000 μm, and particularly preferably 300 μm to 850 μm. When the inner diameter is too small, the pressure loss increases, and there is a tendency to have an adverse effect on filtration. Therefore, the inner diameter of the hollow fiber membrane 3a is preferably 50 μm or more. In addition, when the inner diameter is too large, there is a tendency that it is difficult to maintain the shape of the membrane during spinning. Therefore, it is preferably 3000 μm or less. When using a hollow fiber membrane having the above-mentioned single fiber water permeation rate and inner diameter within a given range, the influence caused by vibration during water flow can be suppressed, and thus higher water permeation performance of the module can be achieved. In one aspect, the outer diameter of the hollow fiber membrane 3a is 100 μm to 3000 μm, preferably 500 μm to 2000 μm.

[0021] The preservation liquid in the hollow fiber membrane module 1 of the present embodiment refers to the liquid filled in the accumulation part 5c formed between the bonding parts 14 at both ends in the housing 5, the space between the top covers 10, 11 and the bonding part 14, and the hollow part and the porous part of the hollow fiber membrane 3a for maintaining the filtration performance of the hollow fiber membrane 3a. As the preservation liquid of the hollow fiber membrane module 1 of the present embodiment, a sterilized liquid is preferably used. For example, the preservation liquid of the present embodiment is ultrapure water (in one aspect, sterilized ultrapure water). The preservation liquid preferably contains substantially no components other than the sterilized liquid. In the production of ultrapure water, it is required that the hollow fiber membrane module does not affect the water quality of the filtered water. Therefore, the preservation liquid of the hollow fiber membrane module 1 preferably has the contents of organic substances, metal ions, chloride ions, and the number of fine particles falling within a given range.

[0022] In the hollow fiber membrane module 1 of the present embodiment, the organic matter content in the preservation liquid is preferably less than 50 ppb in terms of TOC (total organic carbon).

[0023] In addition, if the TOC in the preservation liquid is less than 50 ppb, the amount of filtered water to be discarded at the start of use of the hollow fiber membrane module 1 can be reduced. When the preservation liquid is not completely sterilized (i.e., the bacteria are not completely dead), since the carbon source can be reduced, the growth of bacteria can also be inhibited. In addition, the time for cleaning the organic matter adhering to the hollow fiber membrane at the start of use of the hollow fiber membrane module 1 can be significantly reduced, so that ultrapure water can be provided quickly. In one aspect, the organic matter content in the preservation liquid is less than 50 ppb in terms of TOC (total organic carbon), or 15 ppb or less, or 10 ppb or less.

[0024] In the ultrapure water production process, the mixing of metal ions that will have an adverse effect on semiconductor manufacturing should be avoided, and the lower the content of metal ions in the preservation liquid, the better. In the hollow fiber membrane module 1 of the present embodiment, it is preferred that the concentration of metal ions contained in the preservation liquid is less than 100 ppt. More preferably, when the metal ions contained in the preservation liquid are less than 50 ppt, the water discard time at the start of use of the hollow fiber membrane module 1 can be significantly reduced. In one aspect, the concentration of metal ions contained in the preservation liquid is less than 50 ppt, or 40 ppt or less, or 30 ppt or less, or 20 ppt or less, or 10 ppt or less.

[0025] Similarly, in the hollow fiber membrane module 1 of the present embodiment, it is preferred that the concentration of chloride ions contained in the preservation liquid is less than 1000 ppt. Since chloride ions can also corrode circuits in semiconductor manufacturing, it is required to control them to an extremely low concentration in ultrapure water. The TOC, chloride ions, and metal ion concentrations in the preservation liquid are measured by the methods described in the examples.

[0026] The pure water in the present embodiment can be water obtained by treating river water, etc. with a microfiltration membrane, a reverse osmosis membrane, an ion exchange resin, and UV sterilization, etc. In one aspect, the specific resistance value of the pure water is 1.0 MΩ·cm or more. In one embodiment, the number of particles with a diameter of 50 nm or more in pure water is 25 particles / mL or less, or 20 particles / mL or less, or 10 particles / mL or less, or 5 particles / mL or less, or 3 particles / mL or less. Further, in one embodiment, the number of particles with a diameter of 20 nm or more in pure water is 30 particles / mL or less, or 25 particles / mL or less, 20 particles / mL or less, or 10 particles / mL or less, or 5 particles / mL or less.

[0027] In one embodiment, the pure water is water filtered through a reverse osmosis membrane or an ultrafiltration membrane, etc., which has reduced ionic components (e.g., metal ions and chloride ions) and is not ultrapure water. In one embodiment, the conductivity of the pure water is 1 μS / cm or more. In one embodiment, it is preferable that the organic matter content in the pure water is less than 1 ppm in terms of TOC. In one embodiment, it is preferable that the metal ion concentration in the pure water is less than 1 ppb. Further, the concentration of chloride ions contained in the pure water is preferably less than 1 ppb.

[0028] The pure water in the present embodiment can be used as the cleaning water used in the manufacturing method of the hollow fiber membrane module in the present embodiment, the water to be treated before filtration by the hollow fiber membrane module in the present embodiment, and / or the water in the preservation liquid.

[0029] In the present embodiment, the water to be treated (which can be pure water or ultrapure water) can be used as the filtrate when filtering with the hollow fiber membrane module 1 in the present embodiment (e.g., external pressure filtration or internal pressure filtration) to obtain ultrapure water. In one embodiment, the specific resistance value of the ultrapure water is 18.0 MΩ·cm or more. In one embodiment, the organic matter content in the ultrapure water is 50 ppb or less, or 45 ppb or less, or 40 ppb or less, or 35 ppb or less, or 30 ppb or less in terms of TOC (total organic carbon).

[0030] In one embodiment, the metal ion concentration in the ultrapure water is 50 ppt or less, or 45 ppt or less, or 40 ppt or less, or 35 ppt or less, or 30 ppt or less, or 25 ppt or less, or 20 ppt or less, or 15 ppt or less, or 10 ppt or less. In one embodiment, the chloride ion concentration in the ultrapure water is less than 100 ppt, or 50 ppt or less, or 40 ppt or less, or 30 ppt or less.

[0031] In one aspect, the number of particles with a diameter of 50 nm or more in the ultrapure water produced in this embodiment is 1 particle / mL or less, or 0.7 particle / mL or less, or 0.6 particle / mL or less, or 0.5 particle / mL or less, or 0.3 particle / mL or less, or 0.1 particle / mL or less. In one aspect, the number of particles with a diameter of 20 nm or more in the ultrapure water produced in this embodiment is 3 particles / mL or less, or 2 particles / mL or less, or 1 particle / mL or less, or 0.5 particle / mL or less, or 0.3 particle / mL or less, or 0.1 particle / mL or less.

[0032] When the water to be treated is filtered using the hollow fiber membrane module of this embodiment, the number of particles with a diameter of 50 nm or more in the filtered water can be within the above-specified range. In a preferred aspect, at least one, or at least two, or at least three, or all four of the number of particles with a diameter of 20 nm or more, TOC, metal ion concentration, and chloride ion concentration in the filtered water are within the above-specified range. According to the hollow fiber membrane module of this embodiment, even when the cleaning time at the start of use is very short, ultrapure water can be efficiently produced. It should be noted that the TOC, metal ion concentration, chloride ion concentration, and the number of the above-mentioned particles with a diameter of 20 nm or more or 50 nm or more in the filtered water are measured after 1-hour external pressure filtration at a water temperature of 25°C and a permeation flux of 5 m / d. This external pressure filtration is carried out according to the method described in the examples.

[0033] In one aspect, since particles with a diameter of 20 nm or more are smaller than particles with a diameter of 50 nm or more, it is difficult to prevent them from mixing into the ultrapure water. However, according to the hollow fiber membrane module of this embodiment, in addition to the number of particles with a diameter of 50 nm or more in the ultrapure water after external pressure filtration under the above conditions being within the above range, in a preferred aspect, the number of particles with a diameter of 20 nm or more is also within the above range. The hollow fiber membrane module of this embodiment can be a hollow fiber membrane module that can sufficiently suppress the mixing of substances derived from the hollow fiber membrane module into the filtered water by short-time cleaning after the start of use, that is, it can be a hollow fiber membrane module that simultaneously shortens the cleaning time at the start of use and does not affect the quality of the ultrapure water produced.

[0034] <Manufacturing method of the hollow fiber membrane module> Hereinafter, the manufacturing method of the hollow fiber membrane module 1 of this embodiment will be described. The manufacturing method of the hollow fiber membrane module of this embodiment includes a step of fixing both ends of a plurality of hollow fiber membranes and both ends of a housing with a potting material. In one aspect, the method for manufacturing the hollow fiber membrane module of the present embodiment includes a cutting step of cutting the remaining portion of the potting material in order to open the hollow portions at both ends of the hollow fiber membrane. In one aspect, the cutting step is a step of cutting the remaining portion of the potting material using a diamond band saw. In one aspect, the method for manufacturing the hollow fiber membrane module of the present embodiment includes a step of cleaning the hollow fiber membrane using cleaning water (such as pure water or ultrapure water).

[0035] As the housing constituting the hollow fiber membrane module 1 of the present embodiment, a polysulfone housing similar to the Figure 1 cylindrical housing 5 shown can be used, but the material is not limited thereto. For example, as the material of the housing 5, polyethersulfone, polyphenylsulfone, etc. can also be used. The housing diameter is 50 mm or more and 250 mm or less in one aspect, preferably 100 mm or more and 200 mm or less, and more preferably 120 mm or more and 180 mm or less. If the housing diameter is 50 mm or more, the membrane area of each hollow fiber membrane module is large and the efficiency is good. In addition, if the housing diameter exceeds 250 mm, when casting the hollow fiber membrane and the housing, the heat generation of a large amount of epoxy resin, etc. is large, and there is a tendency that casting becomes difficult. In the cylindrical housing, a rectifying cylinder for rectifying the flow of water inside the housing can be arranged at the upper and lower ends of the housing so that the water flow does not directly impact the hollow fiber membrane bundle.

[0036] As the rectifying cylinder constituting the hollow fiber membrane module 1 of the present embodiment, a polysulfone (transparent polysulfone in one aspect) cylinder can be used. As the material of the rectifying cylinder, polypropylene, polyethylene, polyethersulfone, polyphenylsulfone, etc. can be used. The rectifying cylinder can be arranged inside the housing. As the rectifying cylinder, a rectifying cylinder with a diameter about 10% smaller than the inner diameter of the housing can be appropriately selected. Four protrusions are provided on the side surface of the rectifying cylinder, and by engaging these protrusions with the inner surface of the cylindrical housing, the rectifying cylinder can be pre-fixed at both ends of the cylindrical housing.

[0037] In the method for manufacturing the hollow fiber membrane module 1 of the present embodiment, the hollow fiber membrane bundle 3 is formed by a plurality of hollow fiber membranes 3a. The hollow fiber membrane bundle 3 can be a small bundle formed by being wrapped with a net of polyethylene, etc. in a certain quantity unit. 1 to 4 bundles of hollow fiber membranes 3a can be combined into a small bundle. A plurality of hollow fiber membranes 3a can be combined into one bundle to form the hollow fiber membrane bundle 3, and it is also preferable to combine them in a state of being divided into a plurality of small bundles to form one bundle of the hollow fiber membrane bundle 3. In particular, it is more preferable to form one bundle of the hollow fiber membrane bundle 3 in a state where the small bundles formed by a plurality of hollow fiber membranes 3a are wrapped with a net. By providing a portion within the hollow fiber membrane module 1 that is not filled with hollow fibers (a portion with a low membrane filling density) in this way, the resistance of the water flowing outside the hollow fiber membranes 3a is reduced, and thus higher water permeability performance of the module can be achieved. It should be noted that instead of a net, a non-woven fabric or the like can be used as long as it is formed of a material that can cover the surface of the small bundle and has water permeability.

[0038] The hollow portions are blocked to a position about 2 mm from both ends of the hollow fiber membranes 3a. As a method for blocking the hollow portions, gypsum or the like can be inserted into the hollow portions, or the hollow portions can be sealed with an adhesive such as a urethane resin.

[0039] 《Process of Fixing with Potting Material》 The hollow fiber membrane bundle 3 is inserted into a rectifying cylinder provided in a cylindrical housing, and both ends of the plurality of hollow fiber membranes 3a and both ends of the housing 5 are fixed by casting with an adhesive by a centrifugal casting method. The adhesive here (in one embodiment, it is a potting material or a casting resin) can be appropriately selected. As the adhesive, high molecular materials such as epoxy resin, vinyl ester resin, unsaturated polyester resin, olefin-based polymer, urethane resin, silicone resin, acrylic resin, and fluorine-containing resin are preferred, and one of these high molecular materials or a combination of multiple types can be used. It should be noted that in the ultrapure water production process, the constituent members are required to have heat resistance to hot water and low elution to filtered water. Therefore, an epoxy resin is preferably used as the potting material. Centrifuge until the adhesive has no fluidity. To completely cure it, if necessary, it can also be cured at a temperature of 50 to 90 °C for 5 to 48 hours.

[0040] The hardness of the cured casting resin is preferably 50 or more on the Shore D scale, more preferably 60 or more, and further preferably 70 or more. If the hardness of the cured casting resin is 50 or more on the Shore D scale, it can withstand the water pressure during filtration operation. If the hardness of the cured casting resin is 70 or more on the Shore D scale, it can also withstand the water pressure at high temperatures. On the other hand, if the hardness of the cured casting resin on the Shore D scale is too large, stress will be generated at the interface between the hollow fiber membranes 3a and the adhesive due to the vibration during water flow in the hollow fiber membranes 3a, and this part tends to break easily. From this perspective, the upper limit of the hardness on the Shore D scale is preferably 120 or less. After the casting resin as the potting material is completely cured, both ends of the cast portions of the hollow fiber membranes 3a fixed to both ends of the housing 5 are cut off, and the hollow portions of the hollow fiber membranes 3a are opened to fabricate the hollow fiber membrane module 1. Water (for example, pure water) is sealed in the housing 5 of the fabricated hollow fiber membrane module 1.

[0041] Cutting Process When cutting the remaining part of the resin casting potting material with a saw blade such as a saw, dust of about several millimeters in thickness of the saw blade is generated by the resin cured product and the hollow fiber membrane 3a, and fine particles of the resin cured product as cutting powder accumulate inside the hollow fiber membrane module 1. On the other hand, when using a tool with a long blade length such as a guillotine to cut the remaining part of the potting material, in principle, dust is not generated due to cutting loss. However, when cutting a resin cured product with high hardness (in one embodiment, a large epoxy resin cured product with a hardness of 60 or more on the Shore D scale), there is a possibility that the resin cured product breaks, resulting in very difficult cutting, and fragments of the resin cured product may also become a dust generation source.

[0042] In one embodiment, in the cutting process of the manufacturing method of the hollow fiber membrane module 1 of the present embodiment, in order to open the hollow part of the hollow fiber membrane 3a, the remaining part of the potting material is cut with a diamond band saw. By this method, even when the hardness of the casting resin is high, since the blade thickness is as thin as 1 mm or less, cutting can be efficiently performed while preventing dust generation. Therefore, the hollow fiber membrane module 1 can be manufactured with both good operability and low dust generation. In addition, in one embodiment, in the cutting process of the manufacturing method of the hollow fiber membrane module 1 of the present embodiment, in order to open the hollow part of the hollow fiber membrane 3a, a tool other than a diamond band saw (for example, a circular saw) can also be used to cut the remaining part of the potting material. At this time, it is preferable to further perform the cleaning process described later.

[0043] In the present embodiment, the fine particles are fine particles with a diameter of 20 nm or more or a diameter of 50 nm or more. In one embodiment, the fine particles in the present embodiment are fine particles derived from the potting material generated when manufacturing the hollow fiber membrane module 1 of the present embodiment. The hollow fiber membrane module 1 of the present embodiment manufactured using a diamond band saw has few fine particles derived from the potting material. In one embodiment, the fine particles with a diameter of 20 nm or more and a diameter of 50 nm or more contained in the filtered water can be 3 particles / mL or less and 1 particle / mL or less, respectively. Therefore, at the start of use, the time for cleaning the fine particles eluted from the hollow fiber membrane module 1 can be significantly shortened, and thus ultrapure water can be manufactured quickly.

[0044] In one embodiment, the fine particles with a diameter of 50 nm or more contained in the filtered water are 1 particle / mL or less, or 0.7 particle / mL or less, or 0.6 particle / mL or less, or 0.5 particle / mL or less, or 0.3 particle / mL or less, or 0.1 particle / mL or less. In one embodiment, the number of particles having a diameter of 20 nm or more contained in the filtered water is 3 particles / mL or less, or 2 particles / mL or less, or 1 particle / mL or less, or 0.7 particles / mL or less, or 0.5 particles / mL or less, or 0.3 particles / mL or less, or 0.1 particles / mL or less. It should be noted that the number of particles having a diameter of 20 nm or more and 50 nm or more in the filtered water is measured using Ultra DI 20 and Ultra DI 50 manufactured by Particle Measuring Systems (PMS), respectively.

[0045] In the cutting step of the method for manufacturing the hollow fiber membrane module 1 of the present embodiment, the circumferential speed of the diamond band saw is preferably 10 to 1000 m / minute, more preferably 200 to 800 m / minute, and particularly preferably 300 to 500 m / minute. In order to open the hollow portion of the hollow fiber membrane 3a, when cutting the remaining portion of the potting material with a diamond band saw, by setting the circumferential speed of the diamond band saw within the range given in the present application, the number of particles having a diameter of 20 nm or more and 50 nm or more contained in the filtered water can be 1.5 particles / mL or less and 0.5 particles / mL or less, respectively. Therefore, at the start of use of the hollow fiber membrane module, the time for cleaning the particles eluted from the hollow fiber membrane module 1 can be significantly shortened, and ultrapure water can be rapidly produced, so the productivity is excellent. The faster the circumferential speed of the diamond band saw, the faster the object can be cut. However, due to the increase in frictional heat generated between the diamond band saw and the object and the increase in the number of contacts with the object per unit time, zooming, roughness, and breakage occur on the cut surface of the hollow fiber membrane. On the other hand, if the circumferential speed of the diamond band saw is too slow, the productivity decreases. By controlling the circumferential speed of the diamond band saw within the given range, the effects of the present embodiment can be obtained.

[0046] From the viewpoint of reducing the heat generated when cutting the hollow fiber membrane with a diamond band saw and suppressing the zooming of the cut surface caused by high heat, water can be supplied during the cutting step. In addition, in the use of manufacturing ultrapure water, the cut surface (hollow portions at both ends of the hollow fiber membrane) of the hollow fiber membrane as the outlet on the filtration side requires cleanliness. Therefore, water supply is also preferably performed for the purpose of removing cutting chips and the like from the cut surface. In the cutting step of the method for manufacturing the hollow fiber membrane module 1 of the present embodiment, it is preferable to bring water into contact with the cut surface of the hollow fiber membrane to cool the cut surface. Considering the cleanability of the hollow fiber membrane module, the amount of water brought into contact with the cut surface of the hollow fiber membrane is preferably 0.5 L / minute or more. However, if the amount of water increases too much, the amount of water will become a hazard during cutting and hinder the cutting by the diamond band saw. Therefore, the amount of water brought into contact with the cut surface of the hollow fiber membrane is preferably 5 L / minute or less. By controlling the amount of water used in the cutting step within a given range, the effects of the present embodiment can be obtained. The water brought into contact with the cut surface of the hollow fiber membrane can be pure water or ultrapure water in one aspect, but there is no particular limitation as long as the cooling purpose is achieved. The temperature of the cooling water is preferably 0°C to 50°C. In addition, it is preferable to continuously bring the cooling water into contact with the cut surface of the hollow fiber membrane. In one aspect, the cutting step of the present embodiment includes a process of cooling the cut surface by bringing water in an amount of 0.5 L / minute or more into contact with the cut surface of the hollow fiber membrane when using a diamond band saw.

[0047] By setting the amount of water when cutting the remaining part of the potting material with a diamond band saw to open the hollow part of the hollow fiber membrane 3a within the range given in the present application, the number of particles with a diameter of 20 nm or more and 50 nm or more contained in the filtered water can be 1.5 particles / mL or less and 0.5 particles / mL or less, respectively. Therefore, at the start of use of the hollow fiber membrane module, the time for cleaning the particles eluted from the hollow fiber membrane module 1 can be significantly shortened, and ultrapure water can be produced quickly, so the productivity is excellent.

[0048] 《Cleaning Step》 In one aspect, the method for manufacturing the hollow fiber membrane module 1 of the present embodiment includes a cleaning step. This step can be a step of cleaning the hollow fiber membrane by circulating and filtering the hollow fiber membrane module 1 with cleaning water. The cleaning water can be pure water or ultrapure water in one aspect, but is not limited thereto as long as the cleaning purpose can be achieved. The following will be described by taking the case of using pure water as an example. In one aspect, after the cutting step, by cleaning the hollow fiber membrane module 1 with pure water, undesired substances such as TOC, metal ions, and particles remaining in the hollow fiber membrane module 1 can be efficiently discharged. In one embodiment, the temperature of the pure water (the cleaning temperature in one embodiment) for cleaning the hollow fiber membrane module 1 is preferably 50°C or higher, more preferably 60°C or higher, and further preferably 80°C or higher. If the temperature of the pure water is set to 50°C or higher, undesired substances can be efficiently discharged. If the temperature of the pure water is 80°C or higher, the discharge of undesired substances and sterilization can be carried out simultaneously. The upper limit of the temperature of the pure water is preferably 100°C or lower at which water does not boil, more preferably 95°C or lower, and even more preferably lower than 95°C. Considering the controllability in actual use (preventing violent boiling), it is particularly preferably 90°C or lower.

[0049] By setting the temperature of the pure water for cleaning the hollow fiber membrane module 1 within the range given in the present application, the number of particles with a diameter of 20 nm or more and 50 nm or more contained in the filtered water can be made 1.0 particle / mL or less and 0.5 particle / mL or less, respectively. Therefore, at the start of use of the hollow fiber membrane module, the time for cleaning the particles eluted from the hollow fiber membrane module 1 can be significantly shortened, and ultrapure water can be rapidly produced, so the productivity is excellent. It is considered that if the temperature of the pure water cleaning is high, the viscosity of the water is low, the pure water easily enters the gaps between the attached particles and the components, the Brownian motion becomes stronger, the vibration of the particles becomes violent, and the particles become easily peeled off. Therefore, the higher the cleaning temperature, the higher the cleaning effect. On the other hand, if the cleaning temperature is too high, the pore diameter of the hollow fiber membrane will expand, resulting in relaxation of the membrane and a decrease in the material physical properties of the membrane. By setting the cleaning temperature within the given range, the effects of the present embodiment can be obtained.

[0050] In one embodiment, the pure water cleaning is a circulating cleaning carried out by supplying pure water from the outer surface of the hollow fiber membrane 3a to the inner surface to permeate it, recovering the filtered water from both ends of the housing 5, and supplying the recovered filtered water to the outer surface of the hollow fiber membrane 3a again for circulating filtration. The flow rate of the pure water (preferably the pure water for circulating filtration) depends on the membrane area, but the permeation flux is preferably 3 m / d or more, more preferably 5 m / d or more, further preferably 6 m / d or more, and preferably 7 m / d or less. The higher the permeation flux, the better the efficiency. If it is 3 m / d or more, a good cleaning effect can be obtained. If it is 7 m / d or less, excessive swinging of the membrane caused by the water flow can be prevented, which is advantageous in preventing the breakage of the hollow fiber membrane.

[0051] In one embodiment, the time for cleaning the hollow fiber membrane module 1 is preferably 1 hour or more, more preferably 3 hours or more, and further preferably 5 hours or more. In addition, in one embodiment, the time for cleaning the hollow fiber membrane module 1 is preferably 300 hours or less, more preferably 200 hours or less, and further preferably 100 hours or less. After the cleaning process, in a state where the preservation liquid is sealed in the housing, it is sealed with a sealing member, and any post-treatment such as sterilization is performed to obtain the target hollow fiber membrane module 1. The preservation liquid can be cleaning water or water different from the cleaning water. In one embodiment, the preservation liquid can be ultrapure water.

[0052] "Method for Producing Ultrapure Water" This embodiment also provides a method for producing ultrapure water using a hollow fiber membrane module. By removing fine particles in the water to be treated using the hollow fiber membrane module of this embodiment, it is possible to easily produce ultrapure water that meets the water quality requirements for semiconductor manufacturing and the like.

[0053] Figure 3 To show the Figure 1 detailed configuration of each part of the water treatment device 100 using the hollow fiber membrane module 1 shown. In one embodiment, the method for producing ultrapure water can be implemented using a water treatment device as shown in Figure 3 . It should be noted that in the water treatment device 100 for producing ultrapure water, an external pressure filtration method is envisaged.

[0054] As shown in Figure 3 , the water treatment device 100 is for example used as a final filter for ultrapure water. The water to be treated is supplied from the lower nozzle 5b to the accumulation part 5c on the outer side of the hollow fiber membrane 3a, filtered to the inside (hollow part) side of the hollow fiber membrane 3a, and the filtered water is discharged from the pipes 10a and 11a at both ends of the hollow fiber membrane bundle 3. In addition, the circulating water is discharged through the upper nozzle 5a.

[0055] The water treatment device 100 includes a supply pipe 101 connected to the lower nozzle 5b of the hollow fiber membrane module 1 to supply the water to be treated, and a circulation pipe 102 connected to the upper nozzle 5a to send out the circulating water. Further, a pressure gauge, various valves 101a, 102a, etc. are arranged in the middle of the supply pipe 101 and the circulation pipe 102. In addition, the water treatment device 100 includes a first filtered water collecting pipe 103 and a second filtered water collecting pipe 104 that form the flow path of the filtered water. The first filtered water collecting pipe 103 and the second filtered water collecting pipe 104 are connected to the confluence pipe 105 of the filtered water, and the confluence pipe 105 is connected to an external pipe (not shown). It should be noted that a pressure gauge, various valves 105a, etc. are arranged in the confluence pipe 105.

[0056] Then, when the hollow fiber membrane module 1 is installed with respect to the above water treatment device 100, first, the sealing member 10b that seals the hollow fiber membrane module 1 is removed, and the pure water (preservation liquid) sealed in the hollow fiber membrane module 1 is discarded outside the pipes of the water treatment device 100. Further, thereafter, the hollow fiber membrane module 1 is installed to the pipes of the water treatment device 100.

[0057] Generally, when installing a sterilized hollow fiber membrane module in a water treatment device, in order to prevent contamination by fungi, etc., it is installed in a closed form in a pipe, or installed without discarding the preservation liquid inside the hollow fiber membrane module, and the preservation liquid inside the hollow fiber membrane module is discarded while being replaced with supply water. However, in the case of a water treatment device for ultrapure water used in semiconductor devices, etc., if the preservation liquid inside the hollow fiber membrane module flows into the system, the cleanliness of the ultrapure water will decrease, and it will take time to make the system clean. Therefore, in the present embodiment, a method is adopted in which the preservation liquid inside the hollow fiber membrane module 1 is actively discarded to the outside of the system and then installed in the water treatment device 100.

[0058] The hollow fiber membrane module 1 is longitudinally arranged with the upper nozzle 5a side facing upward. The upper nozzle 5a is connected to the circulation pipe 102. In addition, the pipe 10a of the top cover 10 is connected to the first filtered water collecting pipe 103. In addition, the lower nozzle 5b is connected to the supply pipe 101, and the pipe 11a of the top cover 11 is connected to the second filtered water collecting pipe 104.

[0059] The water to be treated is introduced from the supply pipe 101 through the lower nozzle 5b and then introduced into the accumulation part 5c of the hollow fiber membrane module 1 at a given pressure. Inside the housing 5, most of the introduced water to be treated is filtered by the hollow fiber membrane 3a and reaches the hollow part, and moves upward or downward as filtered water. The filtered water that moves upward or downward is discharged from the openings at the ends of the hollow fiber membrane 3a into the top cover 10 or the top cover 11, and is discharged to the confluence pipe 105 through the respective pipes 10a, 11a, the first filtered water collecting pipe 103 or the second filtered water collecting pipe 104, and is collected through an external pipe. On the other hand, the water to be treated that does not pass through the hollow fiber membrane 3a and rises in the accumulation part 5c inside the housing 5 is discharged from the upper nozzle 5a as circulating water and sent to the circulation pipe 102. The above-mentioned collected filtered water can be recovered as the ultrapure water of the present embodiment.

[0060] Inside the two end portions (in one mode, the upper end portion and the lower end portion) of the hollow fiber membrane bundle 3 accommodated in the housing 5, in order to reduce the bias of the density distribution of the plurality of hollow fiber membranes 3a, bias limiting members 25A and 26A are arranged. As the bias limiting members 25A and 26A, for example, plate-shaped or rod-shaped (columnar) members can be appropriately selected. In the present embodiment, the bias limiting member 25A is in a flat plate shape, and the bias limiting member 26A is in a rod shape. In the present embodiment, the bias limiting members 25A and 26A are inserted into the two end portions of the hollow fiber membrane bundle 3 to reduce the bias of the density distribution of the hollow fiber membranes 3a at the two end portions of the hollow fiber membrane bundle 3. It should be noted that the biasing restriction members 25A and 26A may also be configured to be inserted only into either end portion of the hollow fiber membrane bundle 3. Even if this configuration is adopted, by inserting the biasing restriction members 25A and 26A into either side, the bias of the density distribution of the hollow fiber membranes 3a can be reduced at one end portion of the hollow fiber membrane bundle 3.

[0061] In the present embodiment, as an example of the biasing restriction member, a cross plate 25A having an X-shaped cross section formed by two rectangular flat plates intersecting orthogonally and an insertion rod 26A composed of a plurality of rod-shaped members will be described.

[0062] The cross plate 25A is arranged such that the intersection portion 25b of the two rectangular flat plates extends along the length direction of the hollow fiber membrane bundle 3. The cross plate 25A includes four plate portions 25a radially protruding from the intersection portion 25b (see Figure 4 and Figure 5 ). The upper end portion or the lower end portion of the hollow fiber membrane bundle 3 is divided into four substantially equal parts by the four plate portions 25a, thereby correcting the distribution bias of the hollow fiber membranes 3a.

[0063] In addition, the insertion rod 26A is arranged such that its extending direction is along the length direction of the hollow fiber membrane bundle 3. The number of insertion rods 26A necessary for correcting the bias of the density distribution of the hollow fiber membranes 3a is inserted into each region substantially equally divided by the cross plate 25A. The insertion rods 26A are arranged substantially equally on the circumference of a concentric circle with the intersection portion 25b as the axis in each region, for example (see Figure 4 and Figure 5 ). The bias of the density distribution of the hollow fiber membranes 3a is corrected by the cross plate 25A and the insertion rod 26A. It should be noted that the cross plate 25A is arranged in the adhesive fixing layer while avoiding the opposite side of the upper nozzle 5a or the lower nozzle 5b.

[0064] (Biasing restriction member) In the present embodiment, a biasing restriction member composed of a cross plate 25A and an insertion rod 26A is illustrated. However, for the initial biasing restriction member, for example, the cross-sectional shape may be circular, elliptical, or polygonal such as quadrilateral or hexagon, or star-shaped, plate-shaped, or rod-shaped, and there is no particular limitation. In addition, these members can be used in combination. By combining the flat cross plate 25A and the rod-shaped insertion rod 26A as in the present embodiment, it is possible to easily and appropriately achieve the uniformization of the density distribution of the hollow fiber membranes on the inner end surface of the adhesive fixing layer.

[0065] In addition, from the viewpoint of facilitating the control of the distribution of the hollow fiber membranes, it is preferable that the thickness of the biasing restriction member is 3 times or more and 20 times or less the outer diameter of the hollow fiber membranes. In particular, by setting it to 3 times or more, on the outer end face of the adhesive fixing layer, it is possible to surely make the interval between the hollow fiber membranes formed by arranging the biasing restriction member 3 times or more the outer diameter of the hollow fiber membranes. It should be noted that the "thickness" here refers to the equivalent circle diameter of the portion having the largest cross-sectional area in the longitudinal direction of the biasing restriction member. In addition, the outer diameter of the hollow fiber membranes is usually 0.6 mm to 2.5 mm. Therefore, specifically, a range of 1.8 mm to 50 mm is particularly preferably adopted. It should be noted that it is preferable to form the front end portion of the biasing restriction member into a shape such as a cone that is easy to insert into the hollow fiber membrane bundle 3.

[0066] As the material of the biasing restriction member, polymer materials, inorganic materials, etc. can be widely used, and there is no particular limitation. A material having good compatibility with the adhesive constituting the adhesive fixing layer, expecting a sufficient adhesive effect, and having a tensile elastic modulus equal to or higher than that of the adhesive can be used. In particular, when a hollow fiber membrane module is used for ultrapure water applications, an organic polymer material with less elution of ionic components is preferably used.

[0067] In the production of ultrapure water, in addition to high-pressure conditions (the destination of the water to be treated is at a high place) and high-temperature conditions accompanying sterilization, etc., high water quality is also required. Since the breakage of the membrane and the damage of the potting material have a significant impact on the deterioration of water quality, there is a need to reinforce the potting material constituting the hollow fiber membrane module and to compactly arrange the hollow fiber membrane bundle, etc. The biasing restriction member of the present embodiment helps to reduce the water flow deviation in the hollow fiber membrane module by reinforcing the potting material and aligning the arrangement of the hollow fiber membrane bundle, and thus can suppress the breakage of the hollow fiber membranes.

[0068]

Examples

[0069] In the following examples and comparative examples, the production and characteristic evaluation of the hollow fiber membrane module were carried out as follows.

[0070] <Evaluation method> [Water quality analysis] The analysis of various components in the cleaning water, the water to be treated, and the filtered water was carried out using the following instruments. Number of particles with a diameter of 20 nm or more: UltraDI-20 manufactured by Particle Measuring Systems (PMS) Number of particles with a diameter of 50 nm or more: UltraDI-50 manufactured by Particle Measuring Systems (PMS) TOC: TOC5000A manufactured by Shimadzu Corporation Metal ion concentration: ICP-MS 7500cs manufactured by Agilent Technologies Chloride ion concentration: 930Compact IC manufactured by Metrohm

[0071] [Properties of the hollow fiber membrane] A hollow fiber membrane as shown below was fabricated by the method described in Example 1 of Japanese Patent Laid-Open No. 2-164428. Material: Polysulfone Cut-off molecular weight: 6,000 Da (ultrafiltration membrane) Inner diameter / outer diameter: 0.6 mm / 1.0 mm Water permeability: 0.7 m 3 / hr·m 2 ·atm

[0072] <Fabrication of the hollow fiber membrane module> [Housing for fabricating the hollow fiber membrane module] Material: Polysulfone Shape: Cylindrical Dimensions: Inner diameter / outer diameter of the cylindrical part in the filtration area: 154 mm / 170 mm Inner diameter / outer diameter of the cylindrical part in the nozzle section: 162 mm / 183 mm Inner diameter of the nozzle: 58 mm Length of the cylindrical housing / Center distance between nozzles: 1050 mm / 872 mm

[0073] Prepare two transparent polysulfone cylinders to be used as flow straighteners (dimensions are as described below). Inner diameter / outer diameter at the base end: 142 mm / 147 mm, Inner diameter / outer diameter at the front end: 142 mm / 146 mm, Length: 135 mm, Four protrusions are provided on the side surface of the flow straightener, and the flow straightener is pre-fixed to both ends of the cylindrical housing by engaging these protrusions with the inner surface of the cylindrical housing.

[0074] [Fabrication steps of the hollow fiber membrane module] Prepare a hollow fiber membrane bundle formed by wrapping 11,600 hollow fiber membranes with a polyethylene-made net. Impregnate the hollow part with a urethane resin (manufactured by SanyuRec Co., Ltd., SA-8100) and block the positions about 2 mm from both ends of the hollow fiber membranes of the shaped membrane bundle. At the end of the hollow fiber membrane bundle, as a bias limiting member, use the same epoxy resin as the epoxy resin forming the adhesive fixing layer, and insert a cross shape (cross plate) with a height of 70 mm, a width of 138 mm, and a thickness of 5 mm and a cylindrical insertion rod with a height of 75 mm and a diameter of 10 mm. In addition, the cross plate is arranged in the adhesive fixing layer while avoiding the lower nozzle or the opposite side of the upper nozzle. Among them, the separation distance between the cross plate and the rectifying cylinder is 22 mm, the height of the cross plate in the adhesive layer is 23 mm, and the distance from the inner end face of the adhesive layer to the cross plate is 28 mm. Then, insert the hollow fiber membrane bundle into the rectifying cylinder provided in the cylindrical housing, and inject a thermosetting epoxy resin (main agent: DEN43 1100 parts by weight manufactured by Dow Chemical Company, curing agent: SUNMIDE328 45 parts by weight manufactured by Evonik Company) from both ends by centrifugal casting method, and apply a centrifugal force of 50 G by centrifugal casting method until there is no fluidity. After the centrifugation is completed, heat it in an oven at 50 °C for 24 hours and then heat-cure it at 90 °C for 24 hours to completely cure the epoxy resin. At this time, the hardness of the epoxy resin measured according to JIS Z2246 is 82 on the Shore D scale. Then cut off the remaining part of the potting material of the hollow fiber membrane cast with epoxy resin. Use a diamond band saw (manufactured by Meiwa fosis Co., Ltd., diamond band saw BS-312) or a circular saw (manufactured by Sugiyama Co., Ltd., G2 Tipsaw, outer diameter: 560 mm, number of teeth: 130, tooth thickness: 6.0 mm) for cutting to obtain a hollow fiber membrane module before cleaning. The cutting conditions are as follows. Set the circumferential speed of the diamond band saw within the range shown in Table 1 and cut off the remaining part of the potting material of the hollow fiber membrane. When using a diamond band saw to cut off the remaining part of the potting material of the hollow fiber membrane, make cooling water (pure water at 25 °C) contact the cutting surface of the hollow fiber membrane in the amount within the range shown in Table 1.

[0075] Then, install the hollow fiber membrane module before cleaning manufactured above on the given piping of the water treatment device shown in Figure 3 and rinse the hollow fiber membrane module by circulating cleaning using cleaning water. River water was treated with a microfiltration membrane, a reverse osmosis membrane, and ion exchange resin, and subjected to UV sterilization treatment to produce cleaning water. The specific resistance value of the cleaning water was 18.1 MΩ·cm, the TOC was 30 ppb, the metal ion concentration was 10 ppt, and the number of particles with a diameter of 20 nm or more and 50 nm or more in the cleaning water was 25 particles / mL and 20 particles / mL, respectively.

[0076] At this time, regarding the supply flow rate of the cleaning water supplied to the hollow fiber membrane module, the opening degree of the pump outlet valve was adjusted so that the permeation flux was a given flux, the water volume flowing to the filtration side was set to 98%, and the water volume flowing to the concentrate side was set to 2%. Other cleaning conditions such as the cleaning temperature were set as shown in Table 1. The hollow fiber membrane module was obtained according to the above steps.

[0077] <Initial filtration test: Water quality at the start of using the hollow fiber membrane module> The hollow fiber membrane modules of the examples and comparative examples were subjected to the following water quality tests. Each hollow fiber membrane module was subjected to external pressure filtration for 1 hour at a temperature of 25°C and a permeation flux of 5 m / d using the water to be treated. The water quality analysis results are shown in Table 1.

[0078] River water was treated with a microfiltration membrane, a reverse osmosis membrane, and ion exchange resin, and subjected to UV sterilization treatment to produce the water to be treated. The water quality of the water to be treated was: specific resistance value of 18.1 MΩ·cm, TOC of 30 ppb, chloride ion concentration of 30 ppt, metal ion concentration of 10 ppt, and the number of particles with a diameter of 20 nm or more and 50 nm or more was 25 particles / mL and 20 particles / mL, respectively. At this time, regarding the supply flow rate of the water to be treated supplied to the hollow fiber membrane module, the opening degree of the pump outlet valve was adjusted so that the permeation flow rate was 7.1 m 3 / h, and the valve on the concentrate water side was closed so that the entire amount of the water to be treated flowed to the filtration side. The filtration conditions of the hollow fiber membrane modules of the examples and comparative examples were set as shown in Table 1.

[0079] The measurement of the filtered water quality was carried out at a water temperature of 25°C after the filtration time of the hollow fiber membrane module. The measurement results of the filtered water quality are shown in Table 1. The chloride ion concentration in the filtered water filtered by the hollow fiber membrane modules of Examples 1 to 9 was all 30 to 40 ppt.

[0080] When the hollow fiber membrane modules of Comparative Examples 1 and 2 were subjected to external pressure filtration for a given time, they failed to inhibit the mixing of particles with a diameter of 20 nm or more and 50 nm or more into the filtered water. Therefore, it can be seen that the hollow fiber membrane modules of Comparative Examples 1 and 2 cannot rapidly produce ultrapure water at the start of use and will affect the water quality of the produced ultrapure water. On the other hand, when the hollow fiber membrane modules of Examples 1 to 9 are subjected to external pressure filtration for a given time, it is possible to suppress the mixing of particles with diameters of 20 nm or more and 50 nm or more into the filtered water. Therefore, the hollow fiber membrane modules of Examples 1 to 9 can rapidly produce ultrapure water at the start of use and will not affect the water quality of the produced ultrapure water, and thus ultrapure water can be supplied to semiconductor manufacturing without delay.

[0081]

Table 1

[0082] 1 Hollow fiber membrane module 3 Hollow fiber membrane bundle 3a Hollow fiber membrane 5 Housing 5a Upper nozzle 5b Lower nozzle 5c Accumulation part 10, 11 Top cover 10a, 11a Pipeline 10b Sealing member 12 O-ring 13 Nut 14 Adhesive part 25A Bias limiting member (cross plate) 26A Bias limiting member (insertion rod) 100 Water treatment device 101 Supply pipe 101a, 102a, 105a Various valves 102 Circulation pipe 103 First filtered water collecting pipe 104 Second filtered water collecting pipe 105 Confluence pipe Industrial Applicability

[0083] According to the hollow fiber membrane module and its manufacturing method of the present invention, the production of ultrapure water can be efficiently implemented.

Claims

1. A hollow fiber membrane module, wherein The hollow fiber membrane module comprises a housing and a plurality of hollow fiber membranes accommodated in the housing. Both ends of the hollow fiber membrane and both ends of the shell are fixed by potting materials. The hollow fiber membrane assembly is a filtration membrane assembly with openings at both ends that collects filtered liquid from both ends of the shell. The hollow fiber membrane assembly is used to filter the treated water under external pressure for 1 hour at a water temperature of 25°C and a permeability of 5m / d, and the number of particles with a diameter of 50nm or more in the filtrate is 1 / mL or less.

2. The hollow fiber membrane module according to claim 1, wherein: The hollow fiber membrane module is used to filter the treated water under external pressure for 1 hour at a water temperature of 25° C. and a permeation flux of 5 m / d, and the number of particles with a diameter of 20 nm or more in the filtrate is 3 / mL or less.

3. A method for manufacturing a hollow fiber membrane module according to claim 1 or 2, the method comprising: The process of fixing both ends of the plurality of hollow fiber membranes and both ends of the housing with a potting material, and The remaining portion of the potting material is cut off to open the hollow portions at both ends of the hollow fiber membrane, wherein the cutting step is performed using a diamond band saw.

4. The method for manufacturing a hollow fiber membrane module according to claim 3, wherein: The method further includes, after the cutting step, a step of washing the hollow fiber membrane using pure water at a washing temperature of 50° C. or higher.

5. A method for manufacturing a hollow fiber membrane module according to claim 1 or 2, the method comprising: The process of fixing both ends of the multiple hollow fiber membranes and both ends of the shell with potting materials. a cutting step of cutting off the remaining portion of the potting material to open the hollow portions at both ends of the hollow fiber membrane, and a step of washing the hollow fiber membrane with pure water at 50° C. or higher after the cutting step.

6. The method for manufacturing a hollow fiber membrane module according to claim 4, wherein: The cleaning is to supply the pure water from the outer surface of the hollow fiber membrane to the inner surface to make it permeate, recover the filtered water from both ends of the shell, and supply the recovered filtered water to the outer surface of the hollow fiber membrane again for cyclic cleaning. The permeation flux of the pure water is 5 m / d or more. 7 . The method for manufacturing a hollow fiber membrane module according to claim 4 , wherein the cleaning temperature is 95° C. or lower. 8 . The method for manufacturing a hollow fiber membrane module according to claim 3 , wherein the peripheral speed of the diamond band saw is 10 to 1000 m / min. 9 . The method for manufacturing a hollow fiber membrane module according to claim 3 , wherein the peripheral speed of the diamond band saw is 300 to 500 m / min.

10. The method for manufacturing a hollow fiber membrane module according to claim 3, wherein: When the diamond band saw is used, water is brought into contact with the cut surface of the hollow fiber membrane at an amount of 0.5 L / min or more to cool the cut surface.

11. A method for producing ultrapure water, comprising removing particles from water to be treated using the hollow fiber membrane module according to claim 1 or 2.

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