Hollow fiber membrane module and method for evaluating performance of same

Abstract

The present invention suppresses breakage of a porous hollow fiber membrane at the time of a PrH test and reduces pseudo-failure by the PrH test. In order to achieve this purpose, an example of the present disclosure is a hollow fiber membrane module in which: both end portions of a porous hollow fiber membrane bundle are accommodated within a cylindrical housing with an adhesive fixing part 4 interposed therebetween; the adhesive fixing part 4 has a substantially circular end surface perpendicular to the longitudinal direction of the housing; hollow sections of a plurality of porous hollow fiber membranes 2 are open at both ends of the end surface; and when the degree of dispersion (substantial circle / total area of porous hollow fiber membranes) D, which is the area ratio between the smallest-diameter substantial circle C90 encompassing 90% of the plurality of porous hollow fiber membranes 2 opening in both end surfaces 4t of the adhesive fixing part 4 and the total area (including hollow sections) of the porous hollow fiber membranes 2, is calculated for each of the end surfaces, the lower degree of dispersion (degree of dispersion of first end surface) D1 of the end surfaces is 3.3 or greater, and the dispersion ratio (degree of dispersion of second end surface / degree of dispersion of first end surface) D2 / D1 obtained by dividing the other degree of dispersion (degree of dispersion of second end surface) D2 by the degree of dispersion D1 of the one end surface is 1.1 or greater.

Description

Hollow fiber membrane module and its performance evaluation method

[0001] This invention relates to a hollow fiber membrane module and a method for evaluating its performance.

[0002] Conventionally, hollow fiber membrane modules have been used as blood purifiers and component separators in extracorporeal circulation blood purification treatments (hemodialysis, hemodiafiltration, hemofiltration, plasma separation, etc.), treatment of body cavity fluids such as ascites, and virus removal treatment of protein-containing preparations (plasma-derived preparations, biopharmaceuticals, etc.). When such hollow fiber membrane modules are used for virus removal, hollow fiber membrane modules filled with porous hollow fiber membranes are often used. A hollow fiber membrane module generally has a cylindrical container that houses a bundle of hollow fiber membranes inside and has two ports (inlet port and outlet port) on its side for fluid inlet and outlet, and headers provided at both ends of the cylindrical container that also have fluid inlet and outlet (see, for example, Patent Documents 1 to 4).

[0003] One test used to evaluate the performance of such hollow fiber membrane modules when used for virus removal is the pressure hold test (PrH test), in which a measurement solvent is filled into the outer surface (secondary side) of a porous hollow fiber, and the inner surface (primary side) is pressurized and held for a certain period of time, and the pressure drop (ΔP) due to air leakage is measured. For example, since the PrH test is a non-destructive test, after measuring the ΔP of the hollow fiber membrane module, a correlation line between ΔP and LRV can be obtained by actually measuring the logarithmic removal rate (LRV) of the virus. By using this, ΔP can be converted to LRV, making it possible to evaluate the virus capture performance in the process.

[0004] Now, hollow fiber membrane modules used for virus removal require high virus removal performance, and therefore have small pore sizes. In order to guarantee the desired virus capture performance in PrH tests for hollow fiber membrane modules with small pore sizes, it is necessary to perform PrH tests under high-pressure conditions.

[0005] International Publication No. 2003 / 146663, International Publication No. 2017 / 171015, Chinese Utility Model No. ZL202122628115.3, Japanese Patent Publication No. 2013-208608

[0006] However, the inventors have discovered that when High Flux membranes, which have particularly high water permeability, are measured under high-pressure conditions, an excessive amount of bubbles are generated, preventing the proper formation of a gas-liquid interface. As a result, the apparent pressure drop (ΔP) becomes large, which increases the false failure rate (the percentage of membranes that fail despite having the expected performance) in the PrH test.

[0007] Therefore, the present invention aims to provide a hollow fiber membrane module and a method for evaluating its performance that reduces false failures due to PrH testing.

[0008] One aspect of the present invention is a hollow fiber membrane module comprising a cylindrical housing, a porous hollow fiber membrane bundle formed by bundling a plurality of porous hollow fiber membranes, adhesive fixing portions at both ends of the porous hollow fiber membrane bundle, and at least two ports on the side surface of the cylindrical housing, wherein each of the two end portions of the porous hollow fiber membrane bundle is housed in the cylindrical housing via the adhesive fixing portion, the adhesive fixing portion has a substantially circular end face perpendicular to the longitudinal direction of the cylindrical housing, and the hollow portions of the plurality of porous hollow fiber membranes are open at both ends of the end face, and when the dispersion degree (substantially approximate circle / total cross-sectional area of ​​the porous hollow fiber membrane), which is the area ratio of the substantially approximate circle with the smallest diameter encompassing 90% of the plurality of porous hollow fiber membranes opening at the end face of the adhesive fixing portion to the total cross-sectional area of ​​the porous hollow fiber membranes (including the hollow portions), is calculated, the smaller dispersion degree (dispersion degree of the first end face) is 3.3 or higher. This is a hollow fiber membrane module in which the dispersion ratio (dispersion of the second end face / dispersion of the first end face), obtained by dividing the dispersion of the other end face (dispersion of the second end face) by the dispersion of the first end face, is 1.1 or greater.

[0009] By adopting this configuration, it is possible to suppress the occurrence of false failures in performance evaluation tests of porous hollow fiber membranes without unnecessarily increasing the circulation flow rate. In other words, it is possible to obtain accurate test results while suppressing the rupture of the porous hollow fiber membrane caused by an increase in the circulation flow rate during testing.

[0010] In the hollow fiber membrane module described above, the degree of dispersion of the first end face may be 4.0 or higher.

[0011] In the hollow fiber membrane module as described above, the porous hollow fiber membrane packing ratio, which is the ratio of the total cross-sectional area of ​​the porous hollow fiber membrane to the area of ​​the end face of the adhesive fixing portion, may be 5% or more and 25% or less.

[0012] In the hollow fiber membrane module described above, the porous hollow fiber membrane may have a decreasing pore size from the primary side to the secondary side, with the densest layer located near the outermost layer on the secondary side.

[0013] In the hollow fiber membrane module described above, the permeability of pure water may be 160 to 500 L / hr·m²·bar.

[0014] The hollow fiber membrane module described above may be composed of the porous hollow fiber membrane having a bubble point of 1.40 to 1.80.

[0015] The hollow fiber membrane module described above may be composed of the porous hollow fiber membrane having a load of 0.68 N or more and 2.3 N or less at its tensile breaking point.

[0016] Another aspect of the present invention is a performance evaluation method for a hollow fiber membrane module as described above, comprising: an outer surface space in contact with the outer surface of the porous hollow fiber membrane and an inner surface space in contact with the inner surface of the porous hollow fiber membrane; a filling step of filling the outer surface space with a measurement solvent; a pressurizing step of pressurizing the inner surface space with air at a pressure below the elastic limit pressure of the porous hollow fiber membrane; and a holding step of stopping the pressurization.

[0017] In the performance evaluation method for the hollow fiber membrane module as described above, the method may include a step of measuring the pressure fluctuation value in either the outer surface space or the inner surface space, or a step of measuring the amount of air inflow required to maintain a constant pressure in either space.

[0018] The pressurization step in the performance evaluation method described above may include pressurizing the inside of the hollow portion to a pressure below the elastic limit pressure of the porous hollow fiber membrane.

[0019] The pressurization step in the performance evaluation method described above may include pressurizing the hollow portion to 1.6 MPa or higher.

[0020] In the performance evaluation method described above, the temperature of the measurement solvent may be set to 22 to 26°C.

[0021] In the performance evaluation method described above, a circulation step may be included in which the measurement solvent is introduced into one of the two ports of the hollow fiber membrane module while being discharged from the other port, thereby circulating the measurement solvent in the space on the outer surface side of the hollow fiber membrane module.

[0022] In the performance evaluation method described above, the measurement solvent may be circulated to the secondary side of the hollow fiber membrane module by introducing the measurement solvent from the port closer to the end face with greater dispersion (the second end face) and discharging it from the other port.

[0023] In the circulation process of the performance evaluation method described above, the circulation flow rate of the measurement solvent may be set to 20.0 to 28.0 L per minute.

[0024] In the circulation step of the performance evaluation method described above, the circulation time of the measurement solvent may be set to 10 to 20 seconds.

[0025] Another aspect of the present invention is a hollow fiber membrane module comprising a cylindrical housing, a porous hollow fiber membrane bundle formed by bundling a plurality of porous hollow fiber membranes, adhesive fixing portions at both ends of the porous hollow fiber membrane bundle, and at least two ports on the side surface of the cylindrical housing, wherein each of the end portions of the porous hollow fiber membrane bundle is housed in the cylindrical housing via the adhesive fixing portion, the adhesive fixing portion has a substantially circular end face perpendicular to the longitudinal direction of the housing, and the hollow portions of the plurality of porous hollow fiber membranes are open at both ends of the end face, and the dispersion degree (substantially circular / total cross-sectional area of ​​porous hollow fiber membranes), which is the area ratio of the substantially circular minimum diameter encompassing 90% of the plurality of porous hollow fiber membranes opening at the end face of the adhesive fixing portion, to the total cross-sectional area of ​​the porous hollow fiber membranes (including the hollow portions), is calculated such that the smaller dispersion degree (dispersion degree of the first end face) is 3.7 or higher.

[0026] Another aspect of the present invention is a performance evaluation method for a hollow fiber membrane module as described above, comprising: an outer surface space in contact with the outer surface of the porous hollow fiber membrane and an inner surface space in contact with the inner surface of the porous hollow fiber membrane; a filling step of filling the outer surface space with a measurement solvent; a pressurizing step of pressurizing the inner surface space with air at a pressure below the elastic limit pressure of the porous hollow fiber membrane; and a holding step of stopping the pressurization.

[0027] According to the present invention, it is possible to provide a hollow fiber membrane module and a method for evaluating its performance that reduces false failures in PrH testing.

[0028] This is a schematic diagram showing an example of the configuration of a hollow fiber membrane module in one embodiment of the present invention. This is a diagram showing a porous hollow fiber membrane bundle opening at the end face of the adhesive fixing portion of the hollow fiber membrane module. This is a schematic diagram showing a roughly circular minimum diameter that encompasses 90% of the porous hollow fiber membrane from the center of the porous hollow fiber membrane bundle. This is a schematic diagram showing a hollow fiber membrane module. This is a schematic diagram showing the measurement flow of the NPrH test among the PrH tests. This is a graph showing the behavior of pressure drop when the PrH test fails. This is a diagram showing the state of the gas-liquid interface on the surface of the porous hollow fiber membrane during the PrH test, in cases where (A) a gas-liquid interface is uniformly formed on the membrane surface and (B) a gas-liquid interface is not formed.

[0029] Embodiments of the present invention will be described in detail below with reference to the drawings (see Figure 1, etc.). However, the present invention is not limited to the following embodiments and can be implemented in any form without departing from the spirit of the invention.

[0030] <Hollow Fiber Membrane Module> The porous hollow fiber membrane according to this embodiment is a hollow membrane having a porous structure containing a large number of pores for permeating or trapping substances. The shape of the porous hollow fiber membrane is not particularly limited, but it can have a continuous cylindrical shape. In this specification, the surface located on the inside of the cylinder of the porous hollow fiber membrane is described as the inner surface (primary side), and the surface located on the outside of the cylinder is described as the outer surface (secondary side).

[0031] (Configuration of Hollow Fiber Membrane Module) First, the configuration of the hollow fiber membrane module 1 in the embodiment of the present invention will be described with reference to the drawings.

[0032] Figure 1 is a schematic diagram showing an example of the configuration of a hollow fiber membrane module 1 in an embodiment of the present invention. The hollow fiber membrane module 1 is used as a blood purifier or component separator in extracorporeal circulation blood purification treatment (hemodialysis, hemodiafiltration, hemofiltration, plasma separation, etc.), treatment of body cavity fluids such as ascites, and virus removal treatment of protein-containing preparations (plasma-derived preparations, biopharmaceuticals, etc.). The hollow fiber membrane module 1 in this embodiment comprises a porous hollow fiber membrane 2, a porous hollow fiber membrane bundle 3, an adhesive fixing part (potting part) 4, a housing 5, headers 6, 7, etc. (see Figure 1).

[0033] The porous hollow fiber membrane 2 functions as a separation membrane that separates the components of a fluid to be separated between the inner and outer regions of the porous hollow fiber membrane 2. The specific example of the porous hollow fiber membrane 2 is not particularly limited, and any filtration membrane known to those skilled in the art, such as a microfiltration membrane or an ultrafiltration membrane, can be used. The material of the porous hollow fiber membrane 2 is also not particularly limited, and any material known to those skilled in the art may be used. For example, materials for the porous hollow fiber membrane 2 include polysulfone, polyimide, polyetherimide, polypropylene, polyethersulfone, cellulose, cellulose acetate, polyvinylidene fluoride, polyethylene, polyamide, etc. Alternatively, composite materials thereof may be used. The porous hollow fiber membrane 2 may be coated with a hydrophilic polymer to prevent clogging due to the adsorption of proteins, etc. For example, to impart hydrophilicity, a hydrophobic polymer membrane may be covered with hydrophilic graft chains by graft polymerization.

[0034] The porous hollow fiber membrane bundle 3 is made up of many porous hollow fiber membranes 2 bundled together and is housed within the housing 5 along its longitudinal direction (see Figure 1).

[0035] Next, the fixing portion 4 is made of a potting material (cured adhesive resin), and embeds both ends 3t of the porous hollow fiber membrane bundle 3 inside both ends 5t of the housing 5, and fixes the porous hollow fiber membrane bundle 3 to both ends 5t of the housing 5. The adhesive fixing portion 4 can be formed, for example, by the following method. First, after accommodating the porous hollow fiber membrane bundle 3 in the space inside the housing 5, the main agent and the curing agent of the adhesive resin are injected into the housing 5. Then, by applying a centrifugal adhesion method or the like using a centrifuge or the like, which is an arbitrary method known to those skilled in the art, the porous hollow fiber membranes 2 (and the porous hollow fiber membrane bundles 3) are fixed with the cured adhesive resin inside the housing 5. Further, by cutting and removing the excess adhesive resin in the adhesive fixing portion 4, the end face of the porous hollow fiber membrane bundle 3 is in an open state. The outer peripheral regions at both ends of the adhesive fixing portion 4 become the portions 4e composed only of resin, and the inner region (central region) becomes the portion 4d where the resin has entered the gaps between the porous hollow fiber membranes 2 of the porous hollow fiber membrane bundle 3. The adhesive resin used for the adhesive fixing portion 4 is not particularly limited, and any material known to those skilled in the art may be used. For example, as the adhesive resin, polymer resin materials such as epoxy resin, urethane resin, silicone resin, fluorine-containing resin, and unsaturated polyester resin can be mentioned. One of these resin materials may be used, or a plurality of resin materials may be used in combination.

[0036] The housing 5 is a cylindrical container formed in a cylindrical shape, with both ends 5t in the longitudinal direction (direction of the central axis P of the cylinder) open. Headers (lids) 6 and 7 for pipe connection are provided at the openings at both ends 5t of the housing 5, respectively. The headers 6 and 7 are fixed to the housing 5 by, for example, ultrasonic welding or infrared welding. In addition, nozzles 5a and 5b through which fluid flows are formed on the side surface 5s of the housing 5 near both ends 5t. The nozzles 5a and 5b are each provided to protrude in a direction perpendicular to the longitudinal direction of the housing 5. The material of the housing 5 is not particularly limited and may be any material known to those skilled in the art. For example, the material of the housing 5 may be SUS, polyphenylsulfone, polysulfone, polycarbonate, modified PPE, polyvinyl chloride, polyolefin, ABS resin, etc. The inner diameters of the nozzles 5a and 5b are, for example, 6.0 to 50.0 mm, 6.7 to 40.0 mm, and 8.9 to 30.0 mm.

[0037] The headers 6 and 7 are provided as lid materials at the openings of the end portions 5t of the housing 5. Pipe lines 6a and 7a, to which pipes are connected and which serve as fluid inlets and outlets, are formed in each of the headers 6 and 7. These headers 6 and 7 are joined to the end portion 5t of the housing 5 by, for example, infrared welding or the like and are sealed so that liquid does not leak. The housing 5 and the headers 6 and 7 in the hollow fiber membrane module 1 of the present embodiment are made of an amorphous polymer having predetermined performance (for example, a transmittance of 10% or more and a deflection temperature under load of 120° C. or more (preferably 130° C. or more)). Examples of such amorphous polymers include polyphenyl sulfone (PPSU), polysulfone (PSU), polycarbonate (PC), polyethersulfone (PES), polyarylate (PAR), polyetherimide (PEI), and the like. In performing high-temperature steam sterilization (SIP) before the virus removal step, it is particularly preferable to employ polyphenyl sulfone (PPSU) or polysulfone (PSU) which are excellent in high pressure and high temperature resistance as the amorphous polymer. Further, considering that the hollow fiber membrane module 1 composed of the housing 5 and the headers 6 and 7 is used for virus removal, it preferably has a pressure resistance performance of 0.3 MPa or more, and more preferably has a pressure resistance performance of 0.6 MPa or more and 1.0 MPa or more.

[0038] (Cross-sectional structure of the porous hollow fiber membrane) Next, the cross-sectional structure of the porous hollow fiber membrane 2 of the hollow fiber membrane module 1 in the present embodiment will be described with reference to the drawings.

[0039] FIG. 2 is a view showing a porous hollow fiber membrane bundle 3 that opens at the end face 4t of the adhesion fixing portion 4 shown in FIG. 1. The end face 4t of the adhesion fixing portion 4 is perpendicular to the longitudinal direction along the central axis P of the housing 5. In the cross-section of each porous hollow fiber membrane bundle 3 fixed by the adhesion fixing portion 4, a plurality of porous hollow fiber membranes 2 having hollow portions 2' are arranged (see FIG. 2). The spaces between the respective porous hollow fiber membranes 2 are also filled with an adhesive resin, and this filled space constitutes a part of the adhesion fixing portion 4.

[0040] Figure 3 is a schematic diagram showing the minimum diameter approximate circle that encompasses 90% of the porous hollow fiber membrane 2 from the center 3' of the porous hollow fiber membrane bundle 3 of the hollow fiber membrane module 1 in an embodiment of the present invention.

[0041] Herein, we will explain the term "degree of dispersion" as used in this specification. The degree of dispersion is an index indicating the degree of dispersion of the porous hollow fiber membrane 2. In this specification, the degree of dispersion (approximate circle / total cross-sectional area of ​​porous hollow fiber membrane) is defined as the ratio of the area of ​​an approximate circle C with the smallest diameter that encompasses a predetermined proportion of each porous hollow fiber membrane 2 to the total cross-sectional area of ​​the porous hollow fiber membrane 2 (including the hollow portion 2'). In this embodiment, in particular, the approximate circle C with the smallest diameter that encompasses 90% of the multiple porous hollow fiber membranes 2 that open to the end face 4t of the adhesive fixing portion 4. ９０ The area ratio of the area of ​​the porous hollow fiber membrane 2 to the total cross-sectional area (including the hollow portion 2') is called the degree of dispersion (see Equation 1 below). For example, the degree of dispersion can be controlled by changing the diameter of the sealing dish (not shown) that holds the adhesive applied to the end 3t of the porous hollow fiber membrane bundle 3 during the sealing process. For example, increasing the diameter of the sealing dish can increase the degree of dispersion. More specifically, dispersion can be controlled by gripping the porous hollow fiber membrane bundle 3 with a cylinder so that it does not protrude from the sealing dish and by performing static elimination blowing. [Equation 1] Degree of dispersion = Approximate circle of the smallest diameter that encompasses 90% of the multiple porous hollow fiber membranes of the hollow fiber membrane module C ９０ Area / {[Radius of the inner diameter of the porous hollow fiber membrane]^2 × Pi × Number of porous hollow fiber membranes}

[0042] Furthermore, in this specification, "the approximate circle of the smallest diameter encompassing 90% of the porous hollow fiber membrane" refers to the approximate circle C of the 90% probability ellipse of the fiber coordinates, excluding the porous hollow fiber membrane 2 located at the furthest distance from the center coordinates within the entire porous hollow fiber membrane bundle 3. ９０ This means a circle C. ９０The calculation is performed as follows: First, multiple porous hollow fiber membranes 2 opening at the end face 4t of the adhesive fixing part 4 are replaced with point coordinates on the X and Y axes by image analysis (see Figure 3). Next, the average value of the coordinates recognized as porous hollow fibers is calculated and this is taken as the center 3' of the porous hollow fiber membrane bundle 3. The shape of the probability ellipse (slope and ratio of major axis to minor axis) is determined from the variance-covariance matrix of the point coordinates of all porous hollow fibers. The size of the probability ellipse is determined from a chi-squared distribution with 2 degrees of freedom, and the region where its cumulative distribution function is 0.9 or less is taken as the 90% error ellipse and is approximately a circle C ９０ The following is sought. The method for imaging the multiple porous hollow fiber membranes 2 that open to the end face 4t of the adhesive fixing part 4 used for image analysis is not particularly limited, but a method that has a detection accuracy of 99% or more for the porous hollow fiber membranes 2, such as imaging using a microscope, is preferred.

[0043] In this specification, when calculating the degree of dispersion of the porous hollow fiber membrane 2 at both end faces of the adhesive fixing portion of the hollow fiber membrane module 1, the smaller degree of dispersion is defined as the degree of dispersion D1 of the first end face, and the degree of dispersion of the other end face is defined as the degree of dispersion D2 of the second end face. Furthermore, the end face with the smaller degree of dispersion is defined as the first end face, and the other end face as the second end face.

[0044] Figure 4 schematically shows the hollow fiber membrane module 1 of the present invention.

[0045] The membrane module 1 filled with the porous hollow fiber membrane bundle 3 according to this embodiment can be used for filtration by pressurizing the liquid through the porous hollow fiber membrane 2 from the inner surface space (primary side) to the outer surface space (secondary side) of the porous hollow fiber membrane 2 by passing liquid through the nozzle of the header 6 or header 7, and then recovering the liquid from the nozzle 5a or nozzle 5b of the housing 5.

[0046] In this embodiment, the porous hollow fiber membrane packing ratio, which is the ratio of the total cross-sectional area of ​​the porous hollow fiber membrane to the area of ​​the end face of the adhesive fixing portion, is calculated as follows: [Equation 2] Packing ratio = {[Radius of the inner diameter of the porous hollow fiber membrane]^2 × Pi × Number of porous hollow fiber membranes} / Cross-sectional area of ​​the smallest inner diameter portion within the housing used for the hollow fiber membrane module (excluding the nozzle portion)

[0047] (Method for measuring the water permeability of a porous hollow fiber membrane) In this embodiment, the water permeability of a porous hollow fiber membrane is measured as follows: The effective membrane area is 3.3 cm². ２ The filter assembled to achieve the specified characteristics is subjected to a constant-pressure dead-end filtration at 1.0 bar, and the amount of pure water filtered at 25°C is measured. The permeability is then calculated from the filtration time. The test is performed on three or more evaluation modules, and the average value is taken as the permeability of the porous hollow fiber membrane.

[0048] (Method for measuring the bubble point of a porous hollow fiber membrane) In this embodiment, the bubble point of a porous hollow fiber membrane is measured as follows: The downstream side of the filter membrane, assembled to have an effective membrane area of ​​0.83 cm², is filled with hexafluoroethylene, and the pressure is increased from the upstream side of the filter at the dead end with compressed air. The pressure at which the generation of bubbles is confirmed from the downstream side of the filter (when the air flow rate becomes 2.4 mL / min) is defined as the bubble point.

[0049] (Measurement of porcine parvovirus clearance (PPV-LRV)) In this embodiment, the porcine parvovirus clearance (PPV-LRV) of the porous hollow fiber membrane is measured as follows. A filter assembled to have an effective membrane area of ​​3.3 cm² is subjected to autoclaving at 122°C for 60 minutes. Using commercially available blood donation venoglobulin IH 5% intravenous injection (2.5 g / 50 mL) from Tanabe Mitsubishi Pharma Corporation, a solution is prepared so that the immunoglobulin concentration of the solution is 15 g / L, the sodium chloride concentration is 0.1 M, and the pH is 4.5.

[0050] A solution containing 0.5% by volume of porcine parvovirus (PPV) is spiked into this solution to obtain the filtration solution. The prepared filtration solution is filtered at a constant pressure of 2.0 bar for 180 minutes using a dead end filter.

[0051] The titer (TCID50 value) of the filtrate is measured by a viral assay. The viral clearance of PPV (PPV - LRV) is calculated using the formula LRV = Log(TCID50) / mL (filtrate) - Log(TCID50) / mL (filtrate).

[0052] (Method for measuring gold colloid LRV) In this embodiment, the gold colloid LRV of the porous hollow fiber membrane is measured as follows. A commercially available gold colloid nanoparticle solution containing gold colloid with a particle size of approximately 20 nm is diluted with distilled water for injection (manufactured by Otsuka Pharmaceutical Co., Ltd.), Newcol B13 aqueous solution, and PSSA-Na aqueous solution (sodium polystyrene sulfonate) to prepare the gold colloid solution to be filtered.

[0053] A membrane module with a predetermined membrane area is prepared, and using the prepared gold colloid solution, filtration is performed using internal pressure filtration and a dead-end method at a temperature of 25°C, a membrane differential pressure of 196 kPa, and a filtration rate of 1 L / m. ２ Filtration is performed under these conditions, and a portion of the filtrate is sampled.

[0054] Using SP-ICP-MS (PerkinElmer Japan), the number of particles with a particle size of 17 nm or larger in the source liquid and filtrate was measured, and LRV = log １０ The logarithmic removal rate (LRV) of gold colloid particles is calculated using the formula (A / B). In the formula, A represents the number of particles in the source liquid and B represents the number of particles in the filtrate.

[0055] (Load at the tensile fracture point) In this embodiment, the load at the tensile fracture point of the porous hollow fiber membrane is measured as follows. A porous hollow fiber membrane cut to 10 cm is set in TENSILON (A&D Co., Ltd.), and the tensile speed is set to 100 mm / min to measure the load (N) at the time the porous hollow fiber membrane breaks. The load at the tensile fracture point is not particularly limited, but for example, the lower limit is 0.68 N or more and 2.3 N or less, and more preferably 0.78 N or more and 2.2 N or less.

[0056] The thickness of the porous hollow fiber membrane 2 is not particularly limited, but for example, in a dry state it is 40.0 μm or more and 60.0 μm or less, more preferably 42.0 μm or more and 55.0 μm or less. In the cross-section of the porous hollow fiber membrane 2, the pore diameter decreases from the primary side to the secondary side and then becomes constant, and preferably the porous hollow fiber membrane 2 may have the densest layer near the outermost layer on the secondary side.

[0057] When the hollow fiber membrane module 1 is used for virus removal, the logarithmic reduction value (LRV) of the virus is not particularly limited. For example, if it is 4.00 or more, it is preferable because the virus can be sufficiently removed by membrane filtration. If it is 4.50 or more, 5.00 or more, or 6.00 or more, it is more preferable. If the logarithmic reduction value of the virus is 6.00 or more, the virus is removed and it is considered that almost no virus leaks.

[0058] When the hollow fiber membrane module 1 is used for virus removal, the logarithmic reduction value (LRV) of the gold colloid with a diameter of 30 nm is not particularly limited. For example, it is 1.00 or more, preferably 1.20 or more. The logarithmic reduction value of the gold colloid with a diameter of 20 nm is, for example, 1.00 or more, preferably 1.20 or more. The logarithmic reduction value of the gold colloid with a diameter of 15 nm is, for example, 0.10 or more, preferably 0.20 or more. The logarithmic reduction value of the gold colloid with a diameter of 10 nm is, for example, less than 0.10.

[0059] The bubble point of the porous hollow fiber membrane 2 is not particularly limited. For example, it is 1.30 MPa or more and 1.80 MPa or less, preferably 1.40 MPa or more and 1.80 MPa or less, 1.45 MPa or more and 1.80 MPa or less, 1.50 MPa or more and 1.80 MPa or less. In addition, the characteristics of the porous hollow fiber membrane 2 can also be expressed as the ratio of the bubble point (MPa) to the surface tension (N / m) of the solvent used for measurement. When hydrofluoroether with a surface tension of 13.6 mN / m is used as the test liquid for immersing the membrane, the ratio of the bubble point to the surface tension is 96 or more and 133 or less. More preferably, it is 103 or more and 133 or less, 106 or more and 133 or less, 110 or more and 133 or less.

[0060] The permeation rate of pure water in the porous hollow fiber membrane 2 is not particularly limited. For example, it is 40 L / m ２ / hr / bar or more, 45 L / m ２ / hr / bar or more, or 50 L / m ２ / hr / bar or more. Also, the permeation rate of pure water in the porous hollow fiber membrane 2 is, for example, 400 L / m ２ / hr / bar or less, 380 L / m２ / hr / bar or less, 360L / m ２ / hr / bar or less, or 340 L / m ２ It is less than or equal to / hr / bar.

[0061] The dispersion degree D1 of the first end face of the hollow fiber membrane module 1 is not particularly limited, but the lower limit is 3.3 or higher, preferably 4.0 or higher, and more preferably 4.4 or higher. The upper limit is 6.5, preferably 10.0, and more preferably 20.0 or lower. The range is 3.3 to 20.0, 3.3 to 10.0, 3.3 to 6.5, 4.0 to 20.0, 4.0 to 10.0, 4.0 to 6.5, 4.4 to 20.0, 4.4 to 10.0, and 4.4 to 6.5.

[0062] The dispersion ratio D2 / D1 of the hollow fiber membrane module 1 is, for example, lower limit 1.1 or higher, preferably 1.3 or higher, more preferably 1.4 or higher. Upper limit 6.5 or lower, preferably 3.2 or lower, more preferably 2.1 or lower. The range is 1.1 to 6.5, 1.1 to 3.2, 1.1 to 2.1, 1.3 to 6.5, 1.3 to 3.2, 1.3 to 2.1, 1.4 to 6.5, 1.4 to 3.2, and 1.4 to 2.1.

[0063] The packing rate of the hollow fiber membrane module 1 is, for example, 1% or more at the lower limit, preferably 3% or more, and more preferably 5% or more. The upper limit is 33% or less, preferably 20% or less, and more preferably 10% or less. The range is 1-33%, 1-20%, 1-10%, 3-33%, 3-20%, 3-10%, 5-33%, 5-20%, and 5-10%.

[0064] The effective length of the porous hollow fiber membrane in the hollow fiber membrane module 1 is, for example, 80 mm or more at the lower limit, preferably 90 mm or more, and more preferably 100 mm or more. The upper limit is 220 mm or less, preferably 210 mm or less, and more preferably 200 mm or less. The range is 80-220 mm, 80-210 mm, 80-200 mm, 90-220 mm, 90-210 mm, 90-200 mm, 100-220 mm, 100-210 mm, and 100-200 mm.

[0065] The mechanism by which the effects of the present invention are obtained is unclear, but for example, when a gas-liquid interface is formed between the measurement solvent and the surface of the porous hollow fiber membrane 2 during a PrH test, the bubbles that escape from the membrane surface when the hollow portion 2' is pressurized at the start of measurement escape well because the porous hollow fiber membrane bundle 3 is dispersed to a certain extent or more (see Figure 7). If bubbles that escape from the membrane surface remain in the porous hollow fiber membrane bundle 3, it is thought that this may inhibit the formation of the gas-liquid interface, and the bubbles may escape to the small pore diameter portion where the gas-liquid interface would not normally be destroyed, potentially making the apparent ΔP larger. Also, when forming the gas-liquid interface before the start of measurement, if the porous hollow fiber membrane bundle 3 is not dispersed to a certain extent or more, it may be difficult for the measurement solvent to enter the inside of the porous hollow fiber membrane bundle 3, and it is thought that the gas-liquid interface may not be formed well.

[0066] (Pressure hold test (PrH test))

[0067] As a further example of this embodiment, a PrH test method for a membrane module filled with porous hollow fiber membranes will be described. Note that the pressure hold test in this embodiment includes, but is not limited to, the New Pressure Hold Test (NPrH test) and the Air Diffusion Rate Test (ADR test).

[0068] In the PrH test method for the membrane module according to this embodiment, the measurement solvent is filled into the outer surface space (secondary side) of the membrane module to thoroughly wet the hollow fiber membrane. Then, pressurized air is supplied to the inner surface space (primary side). After reaching a predetermined pressure, the supply of pressure is stopped, and the amount of air leakage through the membrane is measured as a pressure drop (ΔP) by measuring the pressure fluctuation value in either the outer surface space (secondary side) or the inner surface space (primary side), or by measuring the amount of air inflow required to maintain a constant pressure in either space.

[0069] The measurement solvent used in the PrH test method for the membrane module according to this embodiment is not particularly limited as long as it is a liquid with a surface tension equal to or less than that of water, and can be water, hydrofluoroether (HFE), alcohols (ethanol, isobutanol, etc.), or mixtures of various alcohols and water. Note that if the liquid temperature of the measurement solvent used in the PrH test changes, the value of the surface tension will change and will affect the pressure that breaks the gas-liquid interface, so it is necessary to measure within an appropriate temperature range. For example, the lower limit is 20°C or higher, preferably 22°C or higher, and more preferably 24°C or higher. The upper limit is 30°C or lower, preferably 28°C or lower, and more preferably 26°C or lower. The range is 20-30°C, 20-28°C, 20-26°C, 22-30°C, 22-28°C, 22-26°C, 24-30°C, 24-28°C, and 24-26°C.

[0070] The pressurized air used in the PrH test method for the membrane module according to this embodiment is not particularly limited, but instrument air, nitrogen, artificial air (argon-filled), etc., can be used.

[0071] In the PrH test of the membrane module according to this embodiment, the pressure applied to the air in the inner surface space (primary side) is a pressure that is below the elastic limit pressure of the porous hollow fiber. The lower limit of the pressure is, for example, when the intermembrane pressure difference of the porous hollow fiber membrane is greater than 98 kPa.

[0072] The elastic limit pressure is defined as the pressure at which the expansion observed due to the change in the outer diameter of a porous hollow fiber membrane, resulting from the pressure increase when air is applied to the inner surface of the porous hollow fiber membrane, deviates from a linear change. This deviation from the linear change in the expansion of the porous hollow fiber membrane is caused by plastic deformation of the porous hollow fiber membrane. In this embodiment, the elastic limit pressure of the porous hollow fiber membrane is measured when the porous hollow fiber membrane is wetted with water.

[0073] In this embodiment, the elastic limit pressure of the porous hollow fiber membrane can be measured by the following method.

[0074] Prepare a measuring module by sealing one end of a 50 mm long porous hollow membrane with a curable liquid resin such as urethane resin to prevent air leakage, and inserting the other end into a microcoupler (Nitto Kohki Co., Ltd., MC-04PH) and then bonding and fixing it with a curable liquid resin such as urethane resin without filling the hollow portion. Separately, prepare a pressurizing device equipped with a pressure regulating valve, a pressure gauge, and a microcoupler (Nitto Kohki Co., Ltd., MC-10SM) that allows connection of the microcoupler of the measuring module to a piping for compressed air supply. With the measuring module immersed in water, connect it to the pressurizing device and supply compressed air to the hollow portion by increasing the pressure in 20 kPa intervals. Measure the outer diameter of the porous hollow fiber using a dimensional measuring instrument (Keyence Corporation, model LS-9006M). Calculate the percentage change in outer diameter (%) for each measurement pressure using the following formula, and create a graph with the measurement pressure (kPa) on the X axis and the percentage change in outer diameter (%) on the Y axis. Outer diameter change rate (%) = (D / D ０ -1) × 100 (wherein D: outer diameter (μm) at each pressure, D ０ (Initial outer diameter in unpressurized state (μm))

[0075] Next, using five measurement values ​​at 20 kPa intervals from 20 kPa to 100 kPa, a regression line equation (Y = aX) passing through the origin is obtained. Then, an equation (Y = aX + 1) is derived by adding 1 to the right-hand side of this equation, representing an increase of 1% in the outer diameter change rate. The line obtained by the derived equation is added to the graph above, and the highest pressure among the plotted pressures that do not exceed the outer diameter change rate of the line is taken as the elastic limit pressure of the measuring module.

[0076] The test is performed on six or more measurement modules, and the average value is taken as the elastic limit pressure of the porous hollow fiber membrane.

[0077] In the PrH test method for the membrane module according to this embodiment, the measurement solvent may be circulated by filling the membrane module housing with the measurement solvent from one nozzle and discharging it from the other nozzle. The New Pressure Hold Test (NPrH test) is an example of a pressure hold test that circulates the measurement solvent.

[0078] When circulating the measurement solvent in the outer surface space (secondary side) of the membrane module, it is necessary to set the flow rate within an appropriate range to reduce the effect of porous membrane rupture. For example, the lower limit is 1 L / min, preferably 5 L / min, more preferably 10 L / min. The upper limit is 35 L / min, preferably 30 L / min, more preferably 25 L / min. The ranges are 1-35 L / min, 1-30 L / min, 1-25 L / min, 5-35 L / min, 5-30 L / min, 5-25 L / min, 10-35 L / min, 10-30 L / min, and 10-25 L / min. The time for circulating the measurement solvent also affects the value of ΔP. For example, if the time is too long, liquid will flow from the outer surface to the inner surface of the porous hollow fiber membrane, and as a result of liquid flowing from the inner surface space of the porous hollow fiber membrane into the measurement circuit, the piping volume will change and ΔP will increase. Conversely, if the time is too short, a gas-liquid interface will not be properly formed on the outer surface of the porous hollow fiber membrane, and ΔP will increase. Therefore, it is necessary to set the time for circulating the measurement solvent appropriately. For example, the lower limit is 6 seconds or more, preferably 8 seconds or more, and more preferably 10 seconds or more. The upper limit is 24 seconds or less, preferably 22 seconds or less, and more preferably 20 seconds or less. The range is 6 to 24 seconds, 6 to 22 seconds, 6 to 20 seconds, 8 to 24 seconds, 8 to 22 seconds, 8 to 20 seconds, 10 to 24 seconds, 10 to 22 seconds, and 10 to 20 seconds.

[0079] In the PrH test, increasing the pressure applied to the air in the inner surface space (primary side) allows for the detection of a wide range of pore sizes in the porous hollow fiber membrane. Generally, the relationship between the pressure P at which the gas-liquid interface is broken and bubbles are generated, and the pore size D that can break the gas-liquid interface, is expressed as follows: [Equation 3] P = 4 × surface tension of the liquid / D However, applying pressure exceeding the elastic limit pressure of the porous hollow fiber membrane causes plastic deformation of the porous hollow fiber membrane. Therefore, it is preferable to conduct the test at or below the elastic limit pressure, more preferably at about 85% or less of the elastic limit pressure, and even more preferably at about 75% or less.

[0080] When the hollow fiber membrane module according to this embodiment is used for virus removal applications, ΔP, which is used as the pass / fail criterion for the PrH test, is set, for example, based on the virus removal rate (LRV). For example, in the case of a membrane module that is required to have a porcine parvovirus removal rate (PPV-LRV) of 4.0 or higher as the desired performance, it is set as follows.

[0081] First, a correlation line between the porcine parvovirus removal rate (PPV-LRV) and ΔP is created using hollow fiber membrane modules molded with porous hollow fiber membranes of different pore sizes. A ΔP corresponding to a parvovirus removal rate of 4.0 is calculated and used as the criterion for judgment. In other words, if the ΔP is below the criterion, the pressure hold test is passed; if it exceeds the criterion, the pressure hold test is failed.

[0082] Furthermore, in cases where testing with viruses is undesirable, such as with hollow fiber membrane modules with a large membrane surface area, the measurement of the virus removal rate is not limited to filtering the virus. It may be substituted with a method using particles of similar size to the virus, for example, the measurement method for gold colloid LRV. In this case, by separately determining the correlation between gold colloid LRV and viral LRV, it is possible to determine whether the hollow fiber membrane module under test has the desired virus removal rate.

[0083] Figure 5 schematically shows the measurement flow of the NPrH test, a type of PrH test in which the measurement solvent is circulated. The membrane module is placed in a horizontal position, but it may also be placed at an angle (approximately 30 to 45 degrees) so that the port on the outlet side of the measurement solvent is slightly higher. The PrH test is one method for evaluating the pore size distribution of the hollow fiber membrane module 1. There are three measurement steps. In step 1, the measurement solvent is introduced from nozzle 5a of the hollow fiber membrane module 1 and discharged from nozzle 5b, circulating the measurement solvent and forming a gas-liquid interface on the surface of the porous hollow fiber membrane 2. In step 2, gas at a constant pressure is supplied from the conduit 6a towards the hollow portion 2' of the porous hollow fiber membrane 2. In step 3, after reaching the measurement start pressure, the pressure supply is stopped, and the amount of air leakage through the membrane is measured as a pressure drop (ΔP), which is evaluated as the pore size distribution.

[0084] (Determination of Accuracy of Pressure Hold Test) The accuracy of the pressure hold test (PrH test) according to this embodiment is determined as follows. First, a pressure hold test (PrH test) is performed on a certain hollow fiber membrane module, and the result of the pressure hold test (pass or fail) is determined by determining whether it passes or fails against ΔP, which is a judgment criterion set to correspond to the desired performance. Next, for the same hollow fiber membrane module, it is confirmed whether it has the desired performance (PPV-LRV value or gold colloid LRV value, which was the basis for setting the judgment criterion ΔP of the pressure hold test) by a method of directly filtering parvovirus or by filtering gold colloid particles. If it is confirmed that it has the desired performance by a method of directly filtering parvovirus or by filtering gold colloid particles, but the pressure hold test fails, the result of the pressure hold test is determined to be a pseudo-fail.

[0085] (Example 1) In Example 1, as the porous hollow fiber membrane, a porous hollow fiber membrane was prepared by coating a polyethersulfone (PES) membrane with polyhydroxyethyl methacrylate, based on Example 1 of Japanese Patent No. 6385444 (PPV-LRV 5.0 or higher, bubble point 1.70, pure water permeability 350 L / hr·m).２ A bar (with a tensile fracture load of 0.78 N and an effective length of 214 mm) was fabricated.

[0086] A bundle of 1500 porous hollow fiber membranes was inserted into a housing with an inner diameter of 60 mm, and an adhesive resin was injected and mixed into the housing before centrifugal molding. Urethane resin was used as the adhesive resin. In this way, the porous hollow fiber membranes (and the porous hollow fiber membrane bundles themselves) were fixed to each other at one end of the porous hollow fiber membrane bundle with the adhesive resin, and at the same time the porous hollow fiber membranes were bonded to the housing (bonding process). The filling rate was 9.8%.

[0087] The dispersion degree D of multiple porous hollow fiber membranes opening at the end face of the adhesive fixing portion of the hollow fiber membrane module manufactured in Example 1 was calculated by image analysis. The PrH test of the manufactured hollow fiber membrane module was evaluated by the following method. In this example, the PrH test was performed using an NPrH test in which the measurement solvent was circulated. The PrH test measurement method was as follows: First, the primary side of the filter was pressurized to 1.65 MPa. Next, the pressure supply was stopped after reaching the hold pressure (1.60 MPa). At that time, the pressure drop on the primary side due to air leakage through the membrane (ΔP) was measured (see Figure 5). During the measurement, HFE (hydrofluoroether) was constantly circulated to the secondary side of the filter to maintain the gas-liquid interface. The HFE was circulated by flowing in from the port closer to the first end face and flowing out from the other port. The HFE temperature was 24.5°C, the circulation rate was 25.1 L / min, and the circulation time was 10 seconds. In this embodiment, the pass / fail criterion for the PrH test, ΔP, was set to 0.781 or less, corresponding to a PPV-LRV of 4.0 or higher.

[0088] Furthermore, a gold colloid test was conducted on the same hollow fiber membrane module after the PrH test, in accordance with the method described above, to confirm whether it possessed the specified performance (PPV-LRV 4.0 or higher). The pass / fail criterion for the gold colloid test was set at 2.73 or higher, based on its correlation with the separately conducted PPV-LRV test.

[0089] PrH tests and gold colloid tests were performed on multiple hollow fiber membrane modules with different dispersion degrees D and dispersion ratios D2 / D1. The results, along with the measured values ​​of dispersion degree D and dispersion ratio D2 / D1, are summarized in Tables 1 and 2 below. The hollow fiber membrane module of Example 1 passed both the PrH test and the gold colloid test (no false failures occurred in the PrH test).

[0090] (Examples 2 and 3) In Examples 2 and 3, hollow fiber membrane modules were manufactured in the same manner as in Example 1, except that the dispersion degree D1 and dispersion ratio D2 / D1 of the first end face were greater than in Example 1, and PrH tests and gold colloid tests were performed. These hollow fiber membrane modules passed both the PrH test and the gold colloid test (no false failures occurred in the PrH test).

[0091] (Examples 4 and 5) In Examples 4 and 5, hollow fiber membrane modules were manufactured in the same manner as in Example 1, except that the dispersion degree D1 of the first end face was greater than that of Example 1, the dispersion ratio D2 / D1 was smaller than that of Example 1, and in the PrH test, HFE was introduced from the port closer to the second end face and discharged from the other port. PrH tests and gold colloid tests were then performed on these modules. These hollow fiber membrane modules passed both the PrH test and the gold colloid test (no false failures occurred in the PrH test).

[0092] (Examples 6 and 7) In Examples 6 and 7, hollow fiber membrane modules were manufactured in the same manner as in Example 1, except that the first dispersion degree D1 was greater than in Example 1, the dispersion ratio D2 / D1 was greater than in Example 1, and in the PrH test, HFE was introduced from the port closer to the second end face and discharged from the other port. PrH tests and gold colloid tests were then performed on these modules. These hollow fiber membrane modules passed both the PrH test and the gold colloid test (no false failures occurred in the PrH test).

[0093] (Comparative Examples 1-3, 5, 6) In Comparative Examples 1-3, 5, and 6, hollow fiber membrane modules were manufactured in the same manner as in Example 1, except that the dispersion degree D1 of the first end face was smaller than that of Example 1, and the dispersion ratio D2 / D1 was larger than that of Example 1. PrH tests and gold colloid tests were then performed. These hollow fiber membrane modules failed the PrH test but passed the gold colloid test (a pseudo-failure of the PrH test occurred).

[0094] (Comparative Example 4) In Comparative Example 4, hollow fiber membrane modules were manufactured in the same manner as in Example 1, except that the dispersion degree D1 of the first end face was smaller than that of Example 1, and the dispersion ratio D2 / D1 was smaller than that of Example 1. PrH tests and gold colloid tests were then performed. These hollow fiber membrane modules failed the PrH test but passed the gold colloid test (a pseudo-failure of the PrH test occurred).

[0095] (Comparative Example 7) In Comparative Example 7, a hollow fiber membrane module was manufactured in the same manner as in Example 1, except that the dispersion degree D1 of the first end face was greater than that of Example 1, the dispersion ratio D2 / D1 was smaller than that of Example 1, and in the PrH test, HFE was introduced from the port closer to the second end face and discharged from the other port. A PrH test and a gold colloid test were then performed. This hollow fiber membrane module failed the PrH test but passed the gold colloid test (a pseudo-failure of the PrH test occurred).

[0096] As shown in Tables 1 and 2 above, the hollow fiber membrane modules 1 of Examples 1 to 3 had a dispersion degree D1 of 3.2 or higher and a dispersion ratio D2 / D1 of 1.2 or higher at the first end face, passing the gold colloid test and the PrH test (no pseudo-failures occurred in the PrH test). In contrast, the hollow fiber membrane modules 1 of Comparative Examples 1 to 5 had a dispersion ratio D2 / D1 of 1.2 or higher, but the dispersion degree D1 at the first end face was less than 3.2, passing the gold colloid test but failing the PrH test (a pseudo-failure occurred in the PrH test). Furthermore, Comparative Example 6 had a dispersion degree D1 of less than 3.2 and a dispersion ratio D2 / D1 of less than 1.2 at the first end face, passing the gold colloid test but failing the PrH test (a pseudo-failure occurred in the PrH test).

[0097] On the other hand, while Comparative Example 7 had a dispersion degree D of 3.2 or higher, its dispersion ratio D2 / D1 was less than 1.2. As a result, it passed the gold colloid test but failed the PrH test (a pseudo-failure of the PrH test occurred).

[0098] Furthermore, although the hollow fiber membrane modules 1 of Examples 4 to 7 had a dispersion ratio D2 / D1 of less than 1, the dispersion degree D1 of the first end face was 4.4 or higher, and passed the gold colloid test and the PrH test (no pseudo-failures occurred in the PrH test).

[0099] In Examples 1 to 7, it is believed that false failures did not occur because the hollow fiber membrane bundles were dispersed to a certain extent, allowing air bubbles to escape continuously. In particular, in these examples, the measurement solvent was circulated, and in Examples 1 to 3, it is believed that false failures did not occur because the measurement solvent flowed from areas of low dispersion to areas of high dispersion, allowing air bubbles to escape continuously. On the other hand, in Examples 4 to 7, the measurement solvent flowed from areas of high dispersion to areas of low dispersion, but it is believed that false failures did not occur because the dispersion of the porous hollow fiber membrane on the downstream side (the outlet side of the measurement solvent) was high, preventing air bubbles from accumulating.

[0100] The embodiments and examples disclosed herein should be understood in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended.

[0101] While the embodiments described above are examples of preferred implementations of the present invention, they are not limited thereto, and various modifications are possible without departing from the spirit of the invention.

[0102] Some or all of the embodiments described above may also be described as follows. However, the present invention is not limited to the following. [Note 1] A hollow fiber membrane module comprising a cylindrical housing, a porous hollow fiber membrane bundle formed by bundling a plurality of porous hollow fiber membranes, adhesive fixing portions at both ends of the porous hollow fiber membrane bundle, and at least two ports on the side surface of the cylindrical housing, wherein each of the ends of the porous hollow fiber membrane bundle is housed in the cylindrical housing via the adhesive fixing portion, the adhesive fixing portion has a substantially circular end face perpendicular to the longitudinal direction of the cylindrical housing, and the hollow portions of the plurality of porous hollow fiber membranes are open at both ends of the end face, and when the dispersion degree (substantially approximate circle / total cross-sectional area of ​​the porous hollow fiber membrane), which is the area ratio of the substantially approximate circle with the smallest diameter encompassing 90% of the plurality of porous hollow fiber membranes opening at the end face of the adhesive fixing portion to the total cross-sectional area of ​​the porous hollow fiber membrane (including the hollow portion), is calculated, the smaller dispersion degree (dispersion degree of the first end face) is 3.3 or greater. A hollow fiber membrane module in which the dispersion ratio (dispersion of the second end face / dispersion of the first end face), obtained by dividing the dispersion of the other end face (dispersion of the second end face) by the dispersion of the first end face, is 1.1 or greater. [Note 2] The hollow fiber membrane module in which the dispersion of the first end face is 4.0 or greater, as described in Note 1. [Note 3] The hollow fiber membrane module in which the porous hollow fiber membrane packing rate, which is the ratio of the total cross-sectional area of ​​the porous hollow fiber membrane to the area of ​​the end face of the adhesive fixing part, is 5% or more and 25% or less, as described in Note 1 or 2. [Note 4] The hollow fiber membrane module in which the porous hollow fiber membrane has a decreasing pore diameter from the primary side to the secondary side, and is constant thereafter, with the densest layer near the outermost layer on the secondary side, as described in Note 1 to 3. [Note 5] A hollow fiber membrane module in which the porous hollow fiber membrane is composed of the porous hollow fiber membrane, with a pure water permeability of 160 to 500 L / hr・m2・bar, as described in Note 1 to 4. [Note 6] A hollow fiber membrane module according to any one of Notes 1 to 5, comprising the porous hollow fiber membrane having a bubble point of 1.40 to 1.80. [Note 7] A hollow fiber membrane module according to any one of Notes 1 to 6, comprising the porous hollow fiber membrane having a load of 0.68 N or more and 2.3 N or less at the tensile fracture point.[Note 8] A performance evaluation method for a hollow fiber membrane module as described in any one of Notes 1 to 7, comprising: an outer surface space in contact with the outer surface of the porous hollow fiber membrane; and an inner surface space in contact with the inner surface of the porous hollow fiber membrane, the performance evaluation method comprising: a filling step of filling the outer surface space with a measurement solvent; a pressurizing step of pressurizing the inner surface space with air at a pressure below the elastic limit pressure of the porous hollow fiber membrane; and a holding step of stopping the pressurization. [Note 9] The performance evaluation method as described in Note 8, further comprising a step of measuring the pressure fluctuation value of either the outer surface space or the inner surface space, or a step of measuring the amount of air inflow necessary to maintain a constant pressure in either space. [Note 10] The performance evaluation method as described in Note 8 or 9, further comprising pressurizing the inner surface space at 1.6 MPa or higher in the pressurizing step. [Note 11] The performance evaluation method as described in any one of Notes 8 to 10, wherein the temperature of the measurement solvent is set to 22 to 26°C. [Note 12] A performance evaluation method according to any one of Notes 8 to 11, comprising a circulation step of circulating the measurement solvent in the space on the outer surface side of the hollow fiber membrane module by introducing the measurement solvent from one of the two ports of the hollow fiber membrane module and discharging it from the other port. [Note 13] A performance evaluation method according to Note 12, wherein in the circulation step, the measurement solvent is introduced from the port closer to the end face with the greater degree of dispersion (second end face) and discharging it from the other port, thereby circulating the measurement solvent in the space on the outer surface side of the hollow fiber membrane module. [Note 14] A performance evaluation method according to Note 12 or 13, wherein in the circulation step, the circulation flow rate of the measurement solvent is set to 20.0 to 28.0 L per minute. [Note 15] A performance evaluation method according to any one of Notes 12 to 14, wherein in the circulation step, the circulation time of the measurement solvent is set to 10 to 20 seconds.[Note 16] A hollow fiber membrane module comprising a cylindrical housing, a porous hollow fiber membrane bundle formed by bundling a plurality of porous hollow fiber membranes, adhesive fixing portions at both ends of the porous hollow fiber membrane bundle, and at least two ports on the side surface of the cylindrical housing, wherein each of the end portions of the porous hollow fiber membrane bundle is housed in the cylindrical housing via the adhesive fixing portion, the adhesive fixing portion has a substantially circular end face perpendicular to the longitudinal direction of the cylindrical housing, the hollow portions of the plurality of porous hollow fiber membranes are open at both ends of the end face, and the dispersion ratio (dispersion of the second end face / dispersion of the first end face) obtained by dividing the dispersion of the other end face (dispersion of the second end face) by the dispersion of the first end face is 1.1 or more at both end faces of the adhesive fixing portion.

[0103] This invention is particularly suitable for application to hollow fiber membrane modules and methods for evaluating their performance.

[0104] 1…Hollow fiber membrane module 2…Porous hollow fiber membrane 2'…Hollow section 3…Porous hollow fiber membrane bundle 3'…Center 3t…End section 4…Adhesive fixing section 4d…Part where resin has entered the gap between porous hollow fiber membranes 2 4e…Part composed solely of resin 4t…End face 5…Housing 5a, 5b…Nozzle (port) 5t…End section 5s…Side section 6, 7…Header 6a, 7a…Pipeline C…Approximately a circle of the minimum diameter encompassing a predetermined proportion of multiple porous hollow fiber membranes C ９０ ...The smallest diameter approximate circle encompassing 90% of the multiple porous hollow fiber membranes P...Central axis

Claims

A hollow fiber membrane module comprising a cylindrical housing, a porous hollow fiber membrane bundle formed by bundling multiple porous hollow fiber membranes, adhesive fixing portions at both ends of the porous hollow fiber membrane bundle, and at least two ports on the side surface of the cylindrical housing, Each of the ends of the porous hollow fiber membrane bundle is housed in the cylindrical housing via the adhesive fixing portion. The adhesive fixing portion has a substantially circular end face perpendicular to the longitudinal direction of the cylindrical housing, and the hollow portions of the plurality of porous hollow fiber membranes are open at both ends of the end face. At both end faces of the adhesive fixing portion, When calculating the dispersion degree (approximately the approximate circle / total cross-sectional area of ​​the porous hollow fiber membrane), which is the area ratio between the approximate circle with the smallest diameter encompassing 90% of the plurality of porous hollow fiber membranes opening at the end face of the adhesive fixing portion and the total cross-sectional area of ​​the porous hollow fiber membrane (including the hollow portion), the smaller dispersion degree (dispersion degree of the first end face) is 3.3 or higher. A hollow fiber membrane module in which the dispersion ratio (dispersion of the second end face / dispersion of the first end face), obtained by dividing the dispersion of the other end face (dispersion of the second end face) by the dispersion of the first end face, is 1.1 or greater. 　 The hollow fiber membrane module according to claim 1, wherein the dispersion of the first end face is 4.0 or greater. 　 The hollow fiber membrane module according to claim 1, wherein the porous hollow fiber membrane packing rate, which is the ratio of the total cross-sectional area of ​​the porous hollow fiber membrane to the area of ​​the end face of the adhesive fixed portion, is 5% or more and 25% or less. 　 The hollow fiber membrane module according to claim 1, wherein the porous hollow fiber membrane has a decreasing pore size from the primary side to the secondary side, and the pore size remains constant, with the densest layer located near the outermost layer on the secondary side. 　 The hollow fiber membrane module according to claim 1, comprising the porous hollow fiber membrane having a pure water permeability of 160 to 500 L / hr·m²·bar. 　 The hollow fiber membrane module according to claim 1, comprising the porous hollow fiber membrane having a bubble point of 1.40 to 1.

80. The hollow fiber membrane module according to claim 1, comprising the porous hollow fiber membrane having a load of 0.68 N or more and 2.3 N or less at the tensile fracture point. 　 A method for evaluating the performance of a hollow fiber membrane module according to claim 1, It has an outer surface space in contact with the outer surface of the porous hollow fiber membrane, and an inner surface space in contact with the inner surface of the porous hollow fiber membrane. A filling step of filling the outer surface space with a measurement solvent, A pressurization step in which the inner surface space is pressurized with air at a pressure below the elastic limit pressure of the porous hollow fiber membrane, A holding process to stop pressurizing, A performance evaluation method that includes this. 　 The performance evaluation method according to claim 8, comprising the steps of measuring the pressure fluctuation value of either the outer surface space or the inner surface space, or measuring the amount of air inflow required to maintain a constant pressure in either space. 　 The performance evaluation method according to claim 8 or 9, further comprising pressurizing the inner surface space to 1.6 MPa or more in the pressurizing step. 　 The performance evaluation method according to any one of claims 8 to 10, wherein the temperature of the measurement solvent is set to 22 to 26°C. 　 A performance evaluation method according to any one of claims 8 to 11, comprising a circulation step of circulating the measurement solvent in the space on the outer surface side of the hollow fiber membrane module by introducing the measurement solvent from one of the two ports of the hollow fiber membrane module and discharging it from the other port. 　 The performance evaluation method according to claim 12, wherein in the circulation step, the measurement solvent is introduced from the port closer to the end face with the greater degree of dispersion (the second end face) and discharged from the other port, thereby circulating the measurement solvent in the space on the outer surface side of the hollow fiber membrane module. 　 The performance evaluation method according to claim 12 or 13, wherein in the circulation step, the circulation flow rate of the measurement solvent is set to 20.0 to 28.0 L per minute. 　 The performance evaluation method according to any one of claims 12 to 14, wherein the circulation time of the measurement solvent in the circulation step is set to 10 to 20 seconds. 　 A hollow fiber membrane module comprising a cylindrical housing, a porous hollow fiber membrane bundle formed by bundling multiple porous hollow fiber membranes, adhesive fixing portions at both ends of the porous hollow fiber membrane bundle, and at least two ports on the side surface of the cylindrical housing, Each of the ends of the porous hollow fiber membrane bundle is housed in the cylindrical housing via the adhesive fixing portion. The adhesive fixing portion has a substantially circular end face perpendicular to the longitudinal direction of the cylindrical housing, and the hollow portions of the plurality of porous hollow fiber membranes are open at both ends of the end face. At both end faces of the adhesive fixing portion, A hollow fiber membrane module in which the dispersion ratio (dispersion of the second end face / dispersion of the first end face), obtained by dividing the dispersion of the other end face (dispersion of the second end face) by the dispersion of the first end face, is 1.1 or greater.

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