JP2006130396A - Hollow fiber membrane bundle and separation module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separation module having a high capacity, high safety or high capacity stability, excellent in preservation stability and reduced in the number of residual blood hollow fiber membranes. <P>SOLUTION: In the separation module wherein both ends of hollow fiber membrane bundles comprising a polysulfone resin containing polyvinyl pyrrolidone are fixed by a resin, the ratio of hollow fiber membranes, of which the angle of inclination at the parts fixed by the resin is 15° or above, is 0.05% or below and the UV (220-350 nm) absorbance in a liquid extractant of hollow fiber membranes when a test defined by dialytic type kidney device manufacturing approval standards is applied to ten hollow membrane bundles, which are obtained by dividing the hollow fiber membrane bundle in its longitudinal direction after the separation module is sterilized and preserved in a dry state for three months at room temperature and/or preserved in a wet state for one year at room temperature, is 0.10 or below as an average value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a separation module loaded with a hollow fiber membrane bundle that has high performance and high safety. This separation module is superior in workability in the manufacturing process simplified compared to the prior art, suppresses deformation of the hollow fiber membrane in the drying process, improves the uniformity of drying, and deteriorates the components of the hollow fiber membrane. By using a drying method for hollow fiber membrane bundles that takes into account the technical matter of producing hollow fiber membrane bundles that have high performance, high safety, and excellent module assembly and storage stability. Therefore, it is possible to provide a separation module having high performance, high safety and stability of performance, excellent storage stability, and few residual blood hollow fiber membranes.

  In recent years, technologies using selective permeable membranes have made remarkable progress, and so far a wide range of fields such as gas and liquid separation filters, hemodialyzers in the medical field, blood filters, blood component selective separation filters, etc. Practical use in is progressing. As the material of the membrane, cellulose resins (regenerated cellulose, cellulose acetate, chemically modified cellulose, etc.), polyacrylonitrile resins, polymethyl methacrylate resins, polysulfone resins, ethylene vinyl alcohol resins, polyamide resins and the like have been used. Of these, the polysulfone-based resin, in addition to its thermal stability, acid resistance, and alkali resistance, improves the blood compatibility by adding a hydrophilizing agent to the film-forming solution, so that it can be used as a semipermeable membrane material. Attention has been paid to research.

  In blood purification therapy for the treatment of renal failure, etc., hemodialyzer, blood filter or hemodialysis filter using dialysis membrane or ultrafiltration membrane as a separator for the purpose of removing uremic toxins and waste products in blood The module is widely used. In particular, modules using hollow fiber membranes as separation materials are important in the dialyzer field due to advantages such as reduction of the amount of blood circulating outside the body, high efficiency of removing substances in the blood, and productivity during module production. high.

  On the other hand, in order to produce a module by bonding the hollow fiber membrane bundle, it is necessary to dry the hollow fiber membrane bundle. However, a porous membrane made of an organic polymer, especially a dialysis membrane made of a polysulfone-based hydrophobic resin, etc. In addition, it is known that when the ultrafiltration membrane is dried after the film formation, the water permeability is remarkably reduced as compared with that before drying. Therefore, it was necessary to handle the membrane always in a wet state or in a state immersed in water.

  As a countermeasure against this problem, a conventional method has been to pack a low-volatile organic liquid such as glycerin in the pores in the porous film after film formation and before drying. However, since low-volatile organic liquids generally have high viscosity, it takes time for cleaning and removal, and even after the membrane is molded into a module, a small amount of effluent derived from low-volatile organic liquids (low-volatile organic liquids). There was a problem in that various derivatives produced by chemical reaction with liquid were found in the module sealing liquid.

As a method for drying without using a low-volatile organic liquid, a method using an inorganic salt such as calcium chloride in place of the low-volatile organic liquid is disclosed, but the necessity for washing and removing remains unchanged. Moreover, even if it is a trace amount, there is a concern that the remaining inorganic salt may adversely affect the dialysis patient (see Patent Document 1).
JP-A-6-277470

Moreover, as a method for drying the membrane, a method for producing a hollow fiber membrane in which microwave irradiation is performed while performing wet heat treatment with water vapor on the hollow fiber membrane is disclosed (see Patent Document 2). However, there is a drawback of extending the drying time because it is steamed to prevent deformation of the membrane while being dry, and since it is drying after attaching a low volatile organic liquid such as glycerin, The objective of reducing effluent from the membrane is not achieved.
JP 11-332980 A

A hydrophilized film containing polyvinyl pyrrolidone that has been dried without using a low-volatile organic liquid is disclosed (see Patent Documents 3 and 4). These describe the ability to separate plasma components from blood, but it is found that plasma proteins permeate and are not effective as dialysis membranes. In addition, since it is dried at a temperature at which polyvinylpyrrolidone is decomposed and modified, it is an extremely undesirable production method for the purpose of reducing the amount of eluate from the membrane.
JP-A-8-52331 Japanese Patent Publication No.8-9668

In addition, a method for producing a high-performance blood purification membrane by drying a wet membrane having a specific performance at a temperature of 120 ° C. or less without impregnating with a low-volatile organic liquid such as glycerin is disclosed (Patent Document). 5). However, it has been clarified by the same inventors that when this method is dried in the form of a yarn bundle, there is a slight difference in performance between the central portion and the outer peripheral portion of the yarn bundle.
Japanese Patent No. 3281364

As a measure for solving the problem of the drying method disclosed in Patent Document 5 by the same inventors as Patent Document 5, a method of drying by irradiating microwaves is disclosed (see Patent Documents 6 to 9). These methods are preferable in that they are dried without impregnating the low-volatile organic liquid and can be dried without deteriorating the separation performance of the hollow fiber membrane bundle. However, any of these methods is a method in which a gas is passed through the hollow fiber membrane bundle to achieve uniform drying. This method requires the installation of an auxiliary mechanism for ventilating the gas in the hollow fiber membrane bundle in addition to the microwave irradiation mechanism, and has a problem that the structure of the dryer becomes complicated. The method also requires that the hollow fiber membrane bundle to be dried be fixed to an auxiliary mechanism for venting gas into the hollow fiber membrane bundle, the structure of the fixing part becomes complicated, and the hollow fiber membrane bundle is There is a problem that the preparation for drying and the drying operation become complicated, such as setting in the above-mentioned place and controlling the air flow rate.
Another inventor has disclosed a method of drying a hollow fiber membrane bundle by irradiating microwaves while passing air through the hollow fiber membrane bundle under reduced pressure (see Patent Document 10). This method also has the same problem.
JP 2003-175320 A JP 2003-175321 A JP 2003-175322 A JP 2003-284931 A JP-A-9-888

  Further, since the method of the above-mentioned patent document uses ventilation drying together, if the ventilation conditions are not strictly controlled in the ventilation drying, the hollow to be dried in the drying process is caused by the non-uniformity of ventilation in the hollow fiber membrane bundle. Differences in deformation of the hollow fiber membrane such as contraction spots of the yarn membrane occur, causing breakage of the hollow fiber membrane, disorder of arrangement, variation in yarn length, and the like. If the hollow fiber membrane breaks or the disorder of the arrangement occurs, the hollow fiber membrane of the embedding part at both ends by the adhesive will be inclined when modularized, and for example, when used for blood purification, blood drifts and residual blood hollow It leads to the generation of yarn film. In addition, when the hollow fiber membrane is broken or disordered, the insertability of the hollow fiber membrane bundle into the module container in the module assembling process is lowered, and the hollow fiber membrane is damaged and the hollow fiber membrane is deformed in cross section. Will occur. Wounds can lead to blood leaks. In addition, the collapsed hollow fiber membrane causes blood drift and leads to the generation of residual blood. Concerning yarn length fluctuation, when a hollow fiber membrane with a large shrinkage rate and a short yarn length occurs, the adhesive easily enters the hollow part of the hollow fiber membrane when embedding both ends with an adhesive, resulting in clogged hollow fiber membranes. This leads to blood drift and the occurrence of residual blood. On the contrary, when a hollow fiber membrane having a low shrinkage rate and a long yarn length is generated, the hollow fiber membrane is broken or the arrangement is disturbed, causing the above-mentioned problems.

Moreover, the method of the said patent document lacks consideration with respect to the long-term storage stability of a hollow fiber membrane raw material, and the improvement is also required. When a hollow fiber membrane is used as a separation membrane for blood purification therapy, if the elution of the hydrophilic compound increases, the accumulation of the hydrophilic compound that is a foreign substance in the human body during long-term dialysis increases, causing side effects and complications. There is a possibility, and the standard of UV (220-350 nm) absorbance in the extract of the hollow fiber membrane is set in the dialysis artificial kidney device manufacturing approval standard. Also in the method of the above-mentioned patent document, the representative value is measured.
The present inventors have confirmed that the extract extracted by the test method defined by the above-mentioned dialysis artificial kidney device manufacturing approval standard contains hydrogen peroxide that cannot be measured by conventionally known UV absorbance. I found it. It has been found that the presence of hydrogen peroxide accelerates the oxidative degradation of polyvinylpyrrolidone, for example, and increases the elution amount of polyvinylpyrrolidone when the hollow fiber membrane bundle is stored. Furthermore, even if hydrogen peroxide is present in a specific part of the hollow fiber membrane bundle, the deterioration reaction of the hollow fiber membrane bundle material starts from that point and propagates to the entire hollow fiber membrane bundle, so it is used as a module. It has been found that the abundance of the hollow fiber membrane bundle in the longitudinal direction needs to ensure a certain amount or less over the entire region. When carried out by the method of the above-mentioned patent document, the amount of the hydrogen peroxide eluted increases, and when the hollow fiber membrane bundle is stored for a long period of time, the oxidative degradation of polyvinylpyrrolidone is promoted, and the UV (220 to 350 nm) absorbance over time. The problem that increases will occur.

  When carried out by the method of the above-mentioned patent document, non-uniform drying occurs in the longitudinal direction of the hollow fiber membrane bundle from the inlet side to the outlet side of the ventilation, and hydrogen peroxide is locally generated. Connected.

  Moreover, when implemented by the method of the above patent document, the hollow fiber membrane bundle is also measured with respect to UV (220 to 350 nm) absorbance due to non-uniform drying in the longitudinal direction of the hollow fiber membrane bundle from the inlet side to the outlet side of the ventilation. The problem that the fluctuation | variation of the longitudinal direction of this is large generate | occur | produces. This fluctuation leads to a decrease in safety. The fluctuation of UV (220 to 350 nm) absorbance is also reflected in the concentration of polyvinyl pyrrolidone on the outer surface of the hollow fiber membrane, and when the wet hollow fiber membrane bundle is dried, the polyvinyl on the surface of the hollow fiber membrane is dried up. This leads to a problem that partial sticking (partial fixation) between the hollow fiber membranes occurs in a portion where the pyrrolidone concentration is high. If this partial sticking occurs, it will lead to problems such as deterioration of the module assemblability, so improvement is necessary. In the above patent document, no consideration is given to these problems.

  The above-described drying methods of Patent Documents 6 to 10 describe that the moisture content in the dried film is less than 1% by mass in Examples. In addition, any of the above known methods of drying by irradiating microwaves is a method of irradiating microwaves under normal pressure, and no mention is made of the effect of irradiating microwaves under reduced pressure. Absent.

  An object of the present invention is to provide a separation module having high performance, high safety and stability of performance, excellent storage stability, and few residual blood hollow fiber membranes. Such a separation module can be provided by adopting a drying method specific to a hollow fiber membrane bundle capable of producing a hollow fiber membrane bundle excellent in storage stability and module assemblability.

  The present invention relates to a separation module in which both ends of a hollow fiber membrane bundle made of polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin, and the hollow fiber in which the inclination of the hollow fiber membrane in the portion fixed with the resin is 15 degrees or more A hollow fiber membrane bundle having a membrane ratio of 0.05% or less and sterilizing the module and then stored in a dry state at room temperature for 3 months and / or in a wet state at room temperature for 1 year The UV (220-350 nm) absorbance in the hollow fiber membrane extract when the test determined according to the dialysis-type artificial kidney device manufacturing approval standard is carried out is 0.10 or less on average. The present invention provides a separation module characterized by the above.

  The separation module obtained by the method of the present invention is a defective hollow fiber such as a hollow fiber membrane, a crushed hollow fiber membrane and a clogged hollow fiber membrane in which the inclination of the hollow fiber membrane in the portion fixed with resin is 15 degrees or more. The ratio of the membrane is suppressed, and it has the advantage of being excellent in residual blood properties and excellent in long-term storage stability and can be suitably used for blood purification.

  Further, the hollow fiber membrane bundle dried by the method of the present invention improves, for example, the insertion property of the hollow fiber membrane bundle into the module container in the separation module assembling process and the bonding work at the time of module assembly in the next process. To do. Furthermore, the occurrence of defective hollow fiber membranes such as tilted hollow fiber membranes, crushed hollow fiber membranes and clogged hollow fiber membranes due to deformation and shrinkage spots is suppressed, and residual blood properties caused by these defects are improved. There is an advantage. In addition, since the hollow fiber membrane is prevented from being broken or damaged, blood leakage is improved. Further, in the present invention, the wet hollow fiber membrane bundle is restrained by the hollow package, so that the workability of placing the hollow fiber membrane bundle to be dried in the dryer is improved and the dried hollow fiber membrane bundle is It is restrained by a hollow packaging body as a unit of number to be loaded into a module to be assembled using a yarn membrane bundle. The membrane bundle can be loaded into the module container, so that the workability of the loading can be greatly improved, and there is an advantage that the generation of the defective hollow fiber membrane at the time of loading is suppressed.

  A separation module in which both ends of a hollow fiber membrane bundle made of polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin, and a hollow fiber membrane in which the inclination of the hollow fiber membrane of the portion fixed with the resin is 15 degrees or more After the module is sterilized and stored for 1 year at room temperature in a wet state, the hollow fiber membrane bundle is divided into 10 pieces in the longitudinal direction, This is a separation module characterized in that the UV (220-350 nm) absorbance in the hollow fiber membrane extract when the test defined by the kidney device manufacturing approval standards is carried out is 0.10 or less on average. is there. Here, the elution test of the dialysis-type artificial kidney device manufacturing approval standard measures 1 g from the divided hollow fiber membrane bundle. 100 ml of RO water is added to this, extraction is performed at 70 ° C. for 1 hour, and UV (220-350 nm) absorbance of the extract is measured.

  Furthermore, in another aspect of the present invention, in a separation module in which both ends of a hollow fiber membrane bundle made of a polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin, the inclination of the hollow fiber membrane bundle in a portion fixed with the resin The hollow fiber membrane bundle having a degree of hollow fiber membranes of 15% or more at a degree of 0.05% or less and sterilizing the module and then stored in a dry state at room temperature for 3 months in the longitudinal direction The UV (220-350 nm) absorbance in the hollow fiber membrane extract is 0.10 or less on average when the test is divided into 10 and each is subjected to the test defined by the dialysis artificial kidney device manufacturing approval criteria. This is a separation module characterized by this.

  If the detailed aspect of the module of this invention is illustrated, it will be the said module for isolation | separation characterized by the ratio of the number of crushing hollow fiber membranes being 0.05% or less. Similarly, in another example of the present invention, the separation module described above, wherein the ratio of the number of clogged hollow fiber membranes is 0.05% or less. As another example of the present invention, the separation module is characterized in that the ratio of the number of residual blood hollow fiber membranes is 0.05% or less with respect to the total number of hollow fiber membranes per module. It is. By using the separation module of each of these embodiments for blood purification, the performance can be remarkably exhibited.

If the separation module of the present invention is described in more detail, the ratio of the number of hollow fiber membranes having a degree of inclination of the hollow fiber membrane of the portion fixed by the adhesive resin evaluated by the method described below of 15 degrees or more. The hollow fiber membrane bundle after storing for 1 year at room temperature in a state where the module is filled with a liquid mainly composed of water (hereinafter referred to as the ratio of the inclined hollow fiber membrane) is 0.05% or less. The UV (220-350 nm) absorbance in the hollow fiber membrane extract when the test determined according to the dialysis-type artificial kidney device manufacturing approval standard is carried out is 0.10 or less on average. It is preferable that In addition, the liquid filled in the module during the storage evaluation of the above-mentioned module is only water or sodium pyrosulfite, sodium sulfite for preventing deterioration of the hollow fiber membrane material during γ-ray sterilization treatment of the module, Examples thereof include an aqueous solution in which sodium bisulfite, acetone sodium bisulfite, sodium formaldehyde sulfoxylate, ascorbic acid, glycerin and the like are dissolved.
The method for evaluating the ratio of the inclined hollow fiber membrane will be described in detail in the following section “8. Method for evaluating the ratio of the inclined hollow fiber membrane”.

  When the degree of inclination of the hollow fiber membrane exceeds 15 degrees, it becomes difficult for blood to flow, and drift occurs, leading to the generation of a residual blood hollow fiber membrane. The proportion of the inclined hollow fiber membrane is more preferably 0.04% or less, and further preferably 0.03% or less. 0% is even more preferable. If it exceeds 0.05%, the number of residual blood hollow fiber membranes increases, which causes anxiety to dialysis patients. In the present invention, it is preferable that both ends of the characteristic satisfy the above range.

  Analysis of the structure of the hollow fiber membrane in the part fixed with resin in the separation module in which both ends of the hollow fiber membrane bundle are fixed with resin reveals the following. The arrangement ratio which detected what state each fiber which constitutes the hollow fiber membrane bundle is arranged to the arrangement axis direction centering on the fiber arrangement axis direction of the hollow fiber membrane bundle is The fact that it has had a considerable influence on the handling and performance of the separation module. If each fiber constituting the hollow fiber membrane bundle is in a so-called parallel state in which all the fibers are aligned in the same direction with respect to the arrangement axis direction, the blood flow flowing through the hollow fiber membrane bundle in the separation module is in a laminar flow state. Therefore, the ideal blood flow state is maintained, and the ideal state where the blood flow pressure is reduced and there is no residual blood volume in the hollow fiber membrane bundle in the separation module can be maintained. It has been found that grasping the inclination state of the fiber in the manner shown in FIG. 4 is meaningful in grasping the performance of the separation module.

  If the distribution state of the hollow fiber membranes in the portion fixed with the resin is observed, it tends to be seen in FIG. The fact that the hollow fiber membranes are all parallel to the fiber axis direction, that is, 100%, is an extremely ideal state, but it is technically very difficult if human work is added as a real problem. Have difficulty. The distribution curve indicated by the dotted line (1) in FIG. 6 is the most appropriate ideal distribution curve at the laboratory level, the factory production level, or the medical site level of the separation module. The present inventors pay close attention to quality control at such a normal level, and when an expert produces a separation module, as a practical problem, most of them are the solid line (2 In many cases, products conforming to the distribution curve of) are manufactured.

  When the state of the distribution curve of the solid line (2) is further analyzed, the existence ratio of the hollow fiber membrane in which the inclination of the hollow fiber membrane is ± 15 degrees or more with respect to the fiber axis direction in the portion fixed with the resin is 0. It has been found that staying below 05% is very beneficial in terms of reducing the residual blood volume. In other words, it is acceptable if the hollow fiber membrane having a degree of ± 15 degrees or more is 0.05% or less. Of course, a product conforming to the distribution curve indicated by the broken line (3) in FIG. 6 is not appropriate as a separation module. In the present invention, the hollow fiber membrane deviating from ± 15 degrees in the fiber axis direction is 0.05% or less, which means that an average of about 1.5 hollow fiber membrane bundles is used when about 3000 hollow fiber membrane bundles are used. Even if the number of hollow fiber membrane bundles is 10,000, it is only about five, and it can be easily understood that the module of the present invention is a highly precise and highly functional product.

  The fact that many of the inclinations exceed 15 degrees is included in the proper laminar flow state of the blood, a portion like turbulent flow occurs, which inhibits the normal flow of blood. As a result, residual blood volume is generated in that area. In particular, when the hollow fiber membranes are crossed, the crossing portion may adversely affect the blood flow, which may cause the residual blood volume of the hollow fiber membrane in the module to increase. It is important that the degree of inclination is 15% or less to be 0.05% or less. In the module production process, it is important to require a high level of skill, but usually it is very thin and weak. In the case where the hollow fiber membrane bundle is stored in the module, the operational problem related to the occurrence of the disorder of the arrangement of the hollow fiber membrane bundle due to resistance or electrostatic repulsion when the restraint body is removed cannot be ignored. It is also possible to affect the nature of the.

  If the influence of the hollow fiber membrane is analyzed in detail, as the amount of the hydrophilic polymer on the outer surface of the hollow fiber membrane increases, the tendency of the adhesion of the outer surface of the hollow fiber membrane increases accordingly. In addition, if there is a non-uniform portion in the drying of the hollow fiber membrane bundle, the frequency of partial sticking will increase, and when the hollow fiber membrane is stored in the module, the hollow fiber membrane having a large inclination is The separation module is considered to be greatly affected by deformation of the hollow fiber membrane during drying of the hollow fiber membrane, and a deformed hollow fiber membrane such as an inclined hollow fiber membrane is generated. This is closely related to the development of proper drying technology for yarn membrane bundles.

FIG. 7 shows a tendency that the value indicating the range in which the ratio of the hollow fiber membrane having a slope of 15 degrees or more in the portion fixed with the resin is 0.05% or less is related to the residual blood volume. It is. The remaining blood volume is shown in three stages as follows.
1. Stage 1: There is almost no residual blood volume.
2. Stage 2: There is a slight residual blood volume.
3. Stage 3: The presence of residual blood volume is clearly seen.
When the inclination is 15 degrees or more, 0.05% or less means that the residual blood hollow fiber membrane is in a state of 0.01%, 0.03%, 0.05%, for example. It means that it does not exist or can be ignored. If this tendency increases to 0.07%, 1%, 5%, and 10%, it is predicted that the generation rate of residual blood hollow fiber membranes that are monotonically observed from the outside tends to increase. In medical practice, 0.05% or less is appropriate as a reasonable tolerance that hemodialysis can be easily performed without giving an unpleasant mental burden to the patient.

  The UV (220-350 nm) absorbance in the hollow fiber membrane extract is more preferably maintained even when stored for 2 years or longer. For this purpose, the UV (220-350 nm) absorbance after storage for 1 year is more preferably 0.08 or less, and further preferably 0.06 or less. This is preferable because the long-term safety of the separation module can be maintained. In addition, UV (220-350 nm) absorbance after storage is evaluated by an average value when the hollow fiber membrane bundle is divided into 10 pieces in the longitudinal direction and measured for each.

Further, in the separation module of the present invention, when the portion of the module end face where the hollow fiber membrane bundle is fixed with an adhesive is observed by the following method, the ratio of the collapsed hollow fiber membrane is preferably 0.05% or less. . In the present invention, it is preferable that this characteristic satisfies both end faces. 0.04% or less is more preferable, and 0.03% or less is more preferable. 0% is even more preferable. When the ratio of the collapsed hollow fiber membrane exceeds 0.05%, blood becomes difficult to flow, blood drifts and leads to the generation of a residual blood hollow fiber membrane.
The ratio evaluation method of the collapsed hollow fiber membrane of the present invention will be described in detail in the following section “9.

  Furthermore, the separation module of the present invention preferably has a clogged hollow fiber membrane ratio of 0.05% or less measured by the following method. 0.04% or less is more preferable, and 0.03% or less is more preferable. 0% is even more preferable. When the ratio of the clogged hollow fiber membrane exceeds 0.05%, it is not preferable because blood hardly flows and leads to the generation of a residual blood hollow fiber membrane. In the present invention, it is preferable that this characteristic satisfies both end faces. The method for calculating the ratio of the clogged hollow fiber membrane according to the present invention will be described in detail in the following section “10. Ratio of Clogged Hollow Fiber Membrane”.

  In the separation module of the present invention, the ratio of residual blood hollow fiber membranes measured by the following method is preferably 0.05% or less with respect to the total number of hollow fiber membranes per module. 0.04% or less is more preferable, and 0.03% or less is more preferable. 0% is even more preferable. If it exceeds 0.05%, the number of residual blood hollow fiber membranes increases, which causes anxiety to dialysis patients. The method for evaluating the ratio of residual blood hollow fiber membrane according to the present invention will be described in detail in “11. Method for evaluating ratio of residual blood hollow fiber membrane” below.

  As long as the separation module of the present invention is a module in which both ends of a hollow fiber membrane bundle made of polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin, the shape and the like are not limited. An example of the shape is illustrated in FIG.

  The separation module 1 is loaded with a hollow fiber membrane bundle 3 in a cylindrical container 2, and both ends of the hollow fiber membrane bundle 3 are fixed to both ends of the container 2 with an adhesive or the like 4. Is covered with caps 5a and 5b. A dialysate inlet 6a for introducing dialysate into the container 2 is provided near one end of the side of the container 2, and a dialysate outlet 6b for discharging dialysate is provided near the other end. Each is formed to protrude. One cap 5a is formed with a blood introduction port 7a for introducing blood into the container 2, and the other cap 5b is formed with a blood discharge port 7b for discharging blood.

  The blood enters the space formed by the cap 5a and one end surface of the hollow fiber membrane bundle 3 from the blood introduction port 7a as indicated by the arrow A, and the hollow fiber membrane of the hollow fiber membrane bundle 3 is hollow. Passes through the part, enters the space formed by the other end face of the hollow fiber membrane bundle 3 and the cap 5b, and is discharged from the blood outlet 7b as shown by the arrow B. On the other hand, the dialysate enters the container 2 from the dialysate inlet 6a as shown by the arrow C, flows outside the hollow fiber membrane of the hollow fiber membrane bundle 3, and as shown by the arrow D, the dialysate outlet. It is discharged from 6b. At this time, the flow of blood to be dialyzed and the flow of dialysate are so-called opposite flows in opposite directions. During this time, waste in the blood flowing in the hollow fiber membrane is dialyzed into the outer dialysate through the hollow fiber membrane.

  Examples of the material for the container and the cap include polycarbonate, polyester, and polypropylene. Moreover, polyurethane etc. are mentioned as a material of the adhesive agent used for both ends fixing.

  The method of injecting the adhesive used for fixing both ends into the fixing portion is not limited, but a centrifugal bonding method is recommended in which injection is performed using the centrifugal force generated by rotating the module to be injected. The method of the centrifugal bonding method is not limited. For example, sealing jigs are attached to both ends of a container in which a dried hollow fiber membrane bundle is loaded, and set in a centrifugal bonding machine. A predetermined amount of uncured adhesive resin is injected from the dialysate inlets 6a and 6b at a temperature near room temperature while rotating the centrifugal adhesive machine at a predetermined rotational speed, and then the temperature of the centrifugal adhesive machine is injected. The curing temperature is raised and the curing is terminated, or at least the resin is precured until the fluidity of the resin is lost, and the centrifugal bonding machine is stopped. In the latter case, post-curing is performed to complete the curing. Moreover, the injection of the adhesive may be carried out in two or more times.

In the case of the centrifugal bonding method, it is important that the adhesive is uniformly injected into the entire space in the hollow fiber membrane bundle. If this injection becomes non-uniform and a part where the injection amount of the adhesive is insufficient is produced, it leads to poor adhesion. In particular, if there is a portion where the hollow fiber membranes are fixed, penetration of the adhesive is inhibited. Therefore, in order to unravel the adhering portion, for example, so-called yarn trimming treatment in which air is blown from the nozzle onto the end surface of the hollow fiber membrane bundle is performed. Certainly, the present yarn setting treatment is effective for unraveling the fixed hollow fiber membrane, but this treatment is not preferable because the hollow fiber membrane bundle at the end face portion is deformed and the inclined hollow fiber membrane is generated.
The hollow fiber membrane bundle of the present invention is characterized in that the uniformity of the injection of the adhesive is ensured without performing the yarn setting treatment because partial adhesion during drying is suppressed. Therefore, the yarn setting process is not necessary.
However, since it is important to ensure the uniformity of the injection of the adhesive, it is preferable to implement the following measures. For example, it is preferable to select a low viscosity brand as the adhesive. The viscosity after 2 minutes of mixing the two liquids is preferably 2000 mPa · s or less. 1600 mPa · s or less is more preferable. Moreover, it is preferable to lower the packing density of the hollow fiber membrane bundle restrained by the hollow package when the dry hollow fiber membrane bundle is inserted into the container used for module assembly.

  The number of hollow fiber membranes and the length of the hollow fiber membrane bundle to be filled are appropriately set according to market requirements and hollow fiber membrane bundle characteristics. The length and diameter of the container are set so as to match the size of the hollow fiber membrane bundle to be filled. The hollow fiber membrane bundle of the present invention described above is preferably used as the hollow fiber membrane bundle to be filled.

  In addition, the liquid filled in the module during the storage evaluation of the above-mentioned module may be sodium pyrosulfite or sodium sulfite for preventing deterioration of the hollow fiber membrane bundle material during the γ-ray sterilization treatment of the module. And an aqueous solution in which sodium hydrogen sulfite, acetone sodium bisulfite, sodium formaldehyde sulfoxylate, ascorbic acid, glycerin and the like are dissolved.

  Although the achievement means which provides said characteristic is not limited, For example, it can achieve by using the following hollow fiber membrane bundle.

The first characteristic that the hollow fiber membrane bundle to be used in the present invention should have is that the fluctuation range of the shrinkage rate in the longitudinal direction of the hollow fiber membrane in the hollow fiber membrane bundle during drying is in a specific range. That is , it has a feature that the difference in the average value of the hollow fiber membrane length between the outer peripheral portion and the inner peripheral portion of the hollow fiber membrane bundle constrained by the package after the drying is preferably within 3 mm. .
Here, the outer peripheral portion of the hollow fiber membrane bundle refers to an outer peripheral portion that is 1/4 of the radius from the center in the circular cross section of the hollow fiber membrane bundle. Further, the inner peripheral portion means an inner peripheral portion having a quarter of the radius from the center. The average value of the length of the hollow fiber membrane is that 500 pieces are randomly sampled from the hollow fiber membranes sampled from the outer peripheral portion and the inner peripheral portion, and the yarn length is measured for each 500 pieces by the following method. The average value is obtained.

  The “thread length measurement method” required for the calculation is as follows. Each end of each hollow fiber membrane is sandwiched between 5 mm from the end with a KOKUYO W clip mouth width of 15 mm and beans (made by KOKUYO: Cree J36). The hollow fiber membrane is suspended with the clip fixed and the other clip free, and the yarn length is measured with a ruler in this state.

The difference in the average value of the hollow fiber membrane length is more preferably 2 mm or less, and further preferably 1 mm or less. When the difference in the average value of the hollow fiber membrane length exceeds 3 mm, when the hollow fiber membrane bundle is used as a module, the ratio of the inclined hollow fiber membrane or the ratio of the clogged hollow fiber membrane is as described later. For example, the residual blood hollow fiber membrane may increase when used for blood purification. Thus, if the variation of the length of the hollow fiber membrane bundle which can be normally used without trouble is observed, the average value can be allowed to be about 3 mm at the maximum. If this length is exceeded, it is based on the knowledge of the inventors of the present invention that material is wasted and has a considerable influence on the assembly and performance of the module.
In addition to the technical meaning of using a hollow fiber membrane bundle having such a structure that the difference in average values of the hollow fiber membrane lengths is 3 mm or less, in the present invention, the hollow fiber membrane length and the module container It has been found that it is appropriate to satisfy the following relationship.

  Further, the hollow fiber membrane bundle used in the present invention should have the following dimensional characteristics. That is, the length of the dried hollow fiber membrane bundle is set by setting the container length of the separation module to be loaded with the dried hollow fiber membrane bundle to A (mm), and cutting both ends of the hollow fiber membrane bundle at the time of assembling the module. When the nominal length is set to B (mm), the appropriate range technically possible is examined for the setting of the length A + B (mm) after the drying of the hollow fiber membrane bundle. Considering the point of determining the optimum range, the idea of determining the optimum value was devised.

Then, the proper circumstance setting conditions A + B (mm) of the present invention, the module container length for loading the hollow fiber membrane bundle A (mm), the hollow fiber membrane bundle at both ends during the module assembly cut Dainaga When the thickness is B (mm), the ratio of the hollow fiber membrane that is shorter than 1 mm from A + B (mm) (short hollow fiber membrane) and the hollow fiber membrane that is longer than 1 mm (long hollow fiber membrane) is 0. .05% or less.
The hollow fiber membrane bundle is a relatively soft material compared to ordinary fibers and the like, and this handling requires not only a high level of skill, but also the subsequent loading of the hollow fiber membrane bundle into the module. Pursuing the handling and performance of the hollow fiber membrane bundle considering the module container length A (mm) and the cutting margin length B (mm) at both ends of the hollow fiber membrane bundle, which will affect the performance. Is groundbreaking.

  The characteristics of the hollow fiber membrane bundle used in the present invention will be described in more detail. It is preferable that the fluctuation range of the shrinkage rate in the longitudinal direction of the hollow fiber membrane in the hollow fiber membrane bundle during drying is in a specific range. . That is, the hollow fiber membrane bundle length after drying is a ratio of the hollow fiber membrane length per hollow fiber membrane loaded in the separation module being shorter than A + B (mm) by more than 1 mm (ratio of short hollow fiber membranes) It is preferable that the ratio (long hollow fiber membrane ratio) of more than 1 mm longer than A + B (mm) is 0.05% or less. Each of them is more preferably 0.04% or less, further preferably 0.03% or less, and particularly preferably 0%. If the hollow fiber membrane length is shorter than A + B (mm) by more than 1 mm, the adhesive penetrates the hollow part of the hollow fiber membrane when the hollow fiber membrane bundle loaded in the container is embedded and fixed with the adhesive. There is a possibility that clogged hollow fiber membranes are generated. It should be noted that the generation of clogged hollow fiber membranes should be sufficient if the module length A (mm) is originally satisfied, but the adhesive enters the hollow portion from the end of the hollow fiber membrane due to capillary action. Go. This penetration distance varies depending on the type of adhesive and the filling method of the adhesive, but generally exceeds the cutting allowance length. Of course, if the cutting allowance length B is set long, the generation of clogged hollow fiber membranes is suppressed, but setting the cutting allowance length B long leads to loss of the hollow fiber membrane bundle and is economically disadvantageous. Sometimes. Therefore, the cutting allowance length B is preferably 30 mm or less. 20 mm or less is more preferable, 10 mm or less is more preferable, and 7 mm or less is still more preferable.

  On the other hand, if a length longer than 1 mm from A + B (mm) is present, the hollow fiber membrane in the separation module may be loosened, and the hollow fiber membrane may be inclined at the embedding portion with the adhesive. These disadvantages cause blood drift and lead to residual blood. Here, A (mm), which is the container length, is the container length after cutting when the container is cut to complete the separation module after the adhesive treatment for fixing the hollow fiber membrane bundle in the container. That's it. As described above, the present inventors paid attention to the length of the hollow fiber membrane bundle, and further studied the relationship with the module length. The fact that it is excellent in quality, performance and stability of

  The second characteristic to be possessed by the hollow fiber membrane bundle used in the method of the present invention is a characteristic relating to the hydrogen peroxide elution amount of the hollow fiber membrane bundle that dominates the storage stability of the hollow fiber membrane bundle. Is divided into 10 pieces in the longitudinal direction, and when the test defined by the dialysis artificial kidney device manufacturing approval standard is performed, the hydrogen peroxide elution amount is 5 ppm or less at all the divided portions. Is preferred. Here, the hydrogen peroxide elution amount is determined by quantifying hydrogen peroxide in the extract extracted in the elution test of the above-mentioned dialysis-type artificial kidney device manufacturing approval standard.

The hydrogen peroxide elution amount is more preferably 4 ppm or less, and further preferably 3 ppm or less. When the elution amount of hydrogen peroxide exceeds 5 ppm, the storage stability deteriorates due to oxidative deterioration of the module constituent material due to hydrogen peroxide. For example, the elution amount of polyvinylpyrrolidone increases when stored for a long period of time. There are things to do. As for storage stability, the increase in the amount of polyvinylpyrrolidone eluted is the most remarkable phenomenon. In addition, the deterioration of the polysulfone-based polymer causes the hollow fiber membrane bundle to become brittle, or the polyurethane system used for module assembly. There is a possibility that the deterioration of the adhesive is promoted, the amount of elution of the deteriorated product is increased, and the safety is lowered. The increase in the amount of elution due to deterioration caused by the oxidizing action of hydrogen peroxide in the long-term storage can be evaluated by measuring UV (220-350 nm) absorbance set by the dialysis artificial kidney device manufacturing approval standard.
Therefore, in the present invention, the dry hollow fiber membrane bundle obtained by the present invention is stored in a dry box (atmosphere is air) at room temperature for 3 months, and then the hollow fiber membrane bundle is divided into 10 pieces in the longitudinal direction, When each of them is subjected to a test defined by the dialysis artificial kidney device manufacturing approval criteria, the UV (220 to 350 nm) absorbance in the hollow fiber membrane extract is preferably 0.10 or less on average.

  The hollow fiber membrane bundle is mainly composed of a polysulfone resin containing polyvinylpyrrolidone. Of course, it is possible to use other plastic materials such as acrylic resin and cellulose, but when using polysulfone-based resin containing polyvinylpyrrolidone and satisfying the dimensional conditions and characteristics of the hollow fiber membrane bundle, The usefulness can be increased synergistically.

Next, the characteristics of the hollow fiber membrane bundle used in the present invention and the deterioration mechanism thereof will be described in more detail. In the present invention, it is preferable that the characteristics satisfy the following requirements.
The inventors of the present invention, as described above, that the extract extracted by the test method defined by the dialysis-type artificial kidney device manufacturing approval standard contains hydrogen peroxide that cannot be measured by a conventionally known UV absorbance. I found. It has been found that the presence of the hydrogen peroxide accelerates the oxidative degradation of, for example, polyvinyl pyrrolidone and increases the amount of the polyvinyl pyrrolidone eluted when the hollow fiber membrane bundle is stored. Furthermore, even if hydrogen peroxide is present in a part of the hollow fiber membrane bundle, the deterioration reaction of the hollow fiber membrane bundle material starts from that location and propagates throughout the hollow fiber membrane bundle. It was found that it is necessary to secure a certain amount or less over the whole area. When carried out by a conventionally known method, the elution amount of the hydrogen peroxide increases, and when the hollow fiber membrane bundle is stored for a long period of time, the oxidative deterioration of the polyvinyl pyrrolidone is promoted and UV (220 to 350 nm) with time It has been found that the problem of increased absorbance occurs.

Moreover, when it is carried out by a conventionally known method, the longitudinal variation of the hollow fiber membrane bundle is evaluated even when evaluated by UV (220 to 350 nm) absorbance, which is a test method defined by the dialysis-type artificial kidney device manufacturing approval standard. It has been found that there is a problem that is large. This fluctuation leads to a decrease in safety. The fluctuation in UV (220 to 350 nm) absorbance also reflects the surface concentration of polyvinyl pyrrolidone on the outer surface of the hollow fiber membrane bundle, and when the wet hollow fiber membrane bundle is dried, the hollow fiber membrane bundle rises to dryness. The hollow fiber membranes partially stick together (partially fixed) at the portion where the polyvinylpyrrolidone concentration is high on the surface, leading to a problem that module productivity is reduced. Furthermore, it has been found that the partial fixation is affected by the moisture content of the dried hollow fiber membrane bundle and the fluctuation of the moisture content in the longitudinal direction of the hollow fiber membrane bundle. If this partial sticking occurs, it will lead to problems such as deterioration of the module assemblability, so improvement is necessary.
Furthermore, regarding the occurrence of the above-mentioned problems, it has been found that the wet hollow fiber membrane bundle in the manufacturing process of the hollow fiber membrane bundle is greatly affected by the drying method and drying conditions. In particular, it has been found that it is important to suppress the oxidative deterioration of polyvinylpyrrolidone in the drying step and to improve the uniformity of drying.

The third characteristic to be possessed by the hollow fiber membrane used in the method of the present invention is the characteristic that governs the partial fixation of the hollow fiber membrane bundle. The maximum value of UV (220 to 350 nm) absorbance in the hollow fiber membrane extract is less than 0.10 when the test is divided into 10 in the direction and each is subjected to the test defined by the dialysis artificial kidney device manufacturing approval criteria. It is also important that the difference between the maximum value and the minimum value in the same hollow fiber membrane bundle is 0.05 or less.
The UV (220 to 350 nm) absorbance in the extract is an indicator of the polyvinylpyrrolidone content on the surface of the hollow fiber membrane that adversely affects the fixation of the hollow fiber membrane bundle, and the UV in the extract in the longitudinal direction of the hollow fiber membrane bundle. (220 to 350 nm) By suppressing the fluctuation in absorbance, the fluctuation of the content of polyvinylpyrrolidone on the surface of the hollow fiber membrane in the longitudinal direction of the hollow fiber membrane bundle is suppressed, so that the occurrence of partial sticking of the hollow fiber membrane bundle is suppressed. . Moreover, since the suppression of the fluctuation leads to keeping the elution amount of polyvinylpyrrolidone in the entire hollow fiber membrane bundle at a low level, the safety is improved when used for blood purification. Therefore, 0.04 or less is preferable, 0.03 or less is more preferable, and 0.02 or less is even more preferable.

  The maximum value of the UV absorbance is preferably 0 because the content of the hydrophilic polymer on the outer surface that affects the fixation is small and there is no eluate to be extracted. However, in the present invention, the maximum value of UV absorbance (220 to 350 nm) is preferably 0.01 or more and less than 0.1. If it is less than 0.01, the content of the hydrophilic polymer on the inner surface of the film is not sufficient, so that the wettability of the film is poor and the film performance may not be fully exhibited. More preferably, it is 0.015 or more, More preferably, it is 0.02 or more, More preferably, it is 0.025 or more. In addition, when the UV absorbance is 0.1 or more, hydrophilic polymers eluted in the blood accumulate in the body, which may cause complications in long-term dialysis treatment. Therefore, the maximum value of the UV absorbance is more preferably 0.095 or less, further preferably 0.09 or less, and still more preferably 0.085 or less.

  Next, a hollow fiber membrane bundle having the above-mentioned characteristics of the present invention and a method for producing a hollow fiber membrane bundle that satisfies the optimum conditions for loading into a module or a method for obtaining the same will be described as follows.

The hollow fiber membrane bundle of the present invention is a method of drying a wet hollow fiber membrane bundle by microwave irradiation as one of typical methods, and the wet hollow fiber membrane bundle is converted into a dielectric constant and dielectric constant at 1 MHz. In a microwave irradiation oven, restrained by a hollow package made of a resin having a tangent product of 0.02 or less, and the longitudinal direction of the hollow fiber membrane bundle is at an angle of 45 degrees or less with respect to the horizontal. It is preferred to place and dry.
The angle of the hollow fiber membrane bundle is more preferably 30 degrees or less, further preferably 20 degrees or less, and still more preferably 10 degrees or less. If the angle is 45 degrees or more, for example, 90 degrees as disclosed in the prior art, the hollow fiber membrane bundle that has been constrained by water as the drying progresses becomes less concentrated. The degree of freedom of movement of the hollow fiber membrane bundle increases, and the possibility that buckling, which is deformation due to its own weight, for example, increases. When the deformation occurs, the hollow fiber membrane bundle is bent. Further, it leads to disorder in the arrangement between the hollow fiber membrane bundles, the insertability of the hollow fiber membrane bundle into the container at the time of module assembly, and the hollow fiber due to rubbing between the hollow fiber membrane bundle and the container or the hollow fiber membrane bundle during insertion. Occurrence of membrane scratches and collapsed hollow fiber membranes and workability in the bonding process to fix the bundle of hollow fiber membranes after insertion to the container by adhesion, adhesion failure due to adhesion work, generation of inclined hollow fiber membranes and adhesive hollow fibers This leads to problems such as increased generation of clogged hollow fiber membranes due to the penetration of the adhesive into the hollow portion of the membrane. Therefore, the present invention is preferably applied to drying of hollow fiber membrane bundles having a ratio L / D of 2 or more, which is the ratio of the diameter (D) to the length (L) of the hollow fiber membrane bundles. It is more preferable to apply to drying of hollow fiber membrane bundles having L / D of 3 or more.

  It is preferable that the wet hollow fiber membrane bundle is restrained by a hollow package made of a resin having a product of a dielectric constant at 1 MHz and a dielectric loss tangent of 0.02 or less and placed in a dryer. This improves the handleability of the hollow fiber membrane bundle and further improves the workability of arrangement in the dryer. In this case, it is preferable to restrain the wet hollow fiber membrane bundle in consideration of module assembly in the next step. That is, the number of units of the hollow fiber membrane bundle required for the module is constrained by a package that is slightly smaller than the inner diameter of the module container, and the dried hollow fiber membrane bundle is inserted into the container for each package. It is recommended as a particularly preferred method because it is possible to suppress the occurrence of troubles such as the workability of inserting the dry hollow fiber membrane bundle into the container and the occurrence of scratches on the hollow fiber membrane in the work by extracting only the package in a heated state. The In the method, it is preferable to set the unit length of the hollow fiber membrane bundle to be dried to a length corresponding to the length of the container of the module filled with the obtained dry hollow fiber membrane bundle. In this case, it is preferable to set the length of the hollow fiber membrane bundle to be dried in consideration of the degree of shrinkage of the hollow fiber membrane bundle due to drying.

Further, in a preferred embodiment, the hollow package is made of plastic having a circular cross-sectional shape, and the outer diameter thereof is 70 to 99.9% of the inner diameter of the module container loaded with the dry hollow fiber membrane bundle. is there.
The outer diameter of the hollow package is more preferably 80 to 99.0%, more preferably 90 to 98.0%, of the inner diameter of the module container in which the dry hollow fiber membrane bundle is loaded. If it exceeds 99.9%, it is difficult to insert the package into the module container, which is not preferable. On the other hand, if it is less than 70%, the proportion of the hollow fiber membrane bundle in the module container becomes small, so a useless space is generated in the module, or the position of the hollow fiber membrane bundle in the module container is biased. When used as a blood purifier, the dialysis fluid is liable to drift, leading to a reduction in dialysis efficiency. Moreover, the workability | operativity of the adhesion process which fixes a hollow fiber membrane bundle in a container may also fall.

  The thickness of the hollow package is preferably 0.05 to 1 mm. 0.1-0.8 mm is more preferable and 0.15-0.7 mm is still more preferable. If the thickness is less than 0.05 mm, the shape retainability is lowered, the shape tends to be deformed, and the deformation of the hollow fiber membrane bundle is generated and the workability of loading into the container is deteriorated. On the other hand, if the thickness exceeds 1 mm, the effect of improving the shape retention and loading workability is saturated, resulting in excessive quality.

  The filling density of the hollow fiber membrane bundle restrained by the hollow packaging body is the sum of the outer diameter cross-sectional areas of the hollow fiber membranes of the hollow fiber membrane bundle restrained relative to the cross-sectional area of the hollow packaging body. 40 to 90% is preferable. 43 to 80% is preferable, and 46 to 70% is more preferable. If it is less than 40%, useless space volume in the module after assembling the module is increased, and the diameter of the module is increased. Further, for example, when used as a blood purifier, the dialysate drifts and leads to a decrease in dialysis efficiency. On the other hand, if it exceeds 90%, the workability of extraction when the hollow packaging body is extracted when the dry hollow fiber membrane bundle is loaded into the container is deteriorated, and the hollow fiber membrane is crushed or damaged. It is not preferable because the generation is likely to occur and the defective yarn is generated. In addition, in the bonding step of fixing the hollow fiber membrane bundle in the container, the permeability of the adhesive into the space between the hollow fiber membranes is lowered, leading to an increase in the number of defective bonding points, which is not preferable.

The material of the hollow package for restraining the wet hollow fiber membrane bundle is preferably selected from resins having a product of dielectric constant and dielectric loss tangent at 1 MHz of 0.02 or less. 0.018 or less is more preferable, and 0.016 or less is more preferable. Examples of the resin include polyolefin resins such as polyethylene and polypropylene, polyethylene terephthalate resins, polysulfone resins such as polysulfone resins and polyethersulfone resins, polyetheretherketone resins, and polyimide resins. Use of the resin is preferable because microwave permeability is improved and drying uniformity of the hollow fiber membrane bundle is improved. Polyolefin resin has a very low product of dielectric constant and dielectric loss tangent at 1 MHz of 0.0005 or less, is soft, and has a good sliding property of the hollow fiber membrane bundle. This is particularly preferable because it also has the advantage that the film bundle is hardly damaged.
On the other hand, if a resin whose dielectric constant and dielectric loss tangent at 1 MHz exceeds 0.02, such as polyvinyl chloride resin, polymethyl methacrylate resin, and polycarbonate resin, the microwave transmission is reduced. When the package is heated, the temperature of the constrained hollow fiber membrane bundle and the hollow fiber membrane in contact with or in the vicinity thereof increases, and the deterioration of polyvinylpyrrolidone in the hollow fiber membrane increases or the longitudinal direction of the hollow fiber membrane increases. This is not preferable because the drying uniformity decreases and shrinkage spots of the hollow fiber membrane increase.

  The package is preferably a method using a seamless tube-shaped package. For example, it is preferable to use a hollow pipe or the like. In particular, it is more preferable to fill a hollow fiber membrane bundle in a wet state into a film or sheet that has been previously formed into a tube shape by a fusing seal or the like.

  The package of the hollow fiber membrane bundle is preferably placed in a tray and placed in a dryer. This method further improves the workability of the drying process. There is no limitation on the shape of the tray. Examples include a method of storing and fixing the package in the space. From the viewpoint of workability, it is preferable to attach a semicircular recess according to the shape of the package on the upper surface of the tray and fix the dried hollow fiber membrane bundle restrained by the package in this recess. The number of dry hollow fiber membrane bundles fixed to one tray is not limited. A method of fixing a plurality is preferable from the viewpoint of further improving the workability of arrangement in the dryer.

The material of the tray is preferably selected from resins having a product of a dielectric constant at 1 MHz and a dielectric loss tangent of 0.02 or less as in the case of the package. 0.018 or less is more preferable, and 0.016 or less is more preferable. Examples of the resin include polyolefin resins such as polyethylene and polypropylene, polyethylene terephthalate resins, polysulfone resins such as polysulfone resins and polyethersulfone resins, polyetheretherketone resins, and polyimide resins. Use of the resin is preferable because microwave permeability is improved, heat generation of the tray is suppressed, and drying uniformity of the hollow fiber membrane bundle is improved. Unlike the case of the package, the capacity is large and it is necessary to use it repeatedly. Therefore, it is preferable to use a polysulfone resin or a polyether ether ketone resin having excellent heat resistance.
On the other hand, if a resin whose dielectric constant and dielectric loss tangent at 1 MHz exceeds 0.02, such as polyvinyl chloride resin, polymethyl methacrylate resin, and polycarbonate resin, the microwave transmission is reduced. The heat generation of the tray increases, the temperature of the package in the part in contact with the tray and the hollow fiber membrane bundle in the vicinity thereof increases, the deterioration of polyvinylpyrrolidone in the hollow fiber membrane of the part increases, and the hollow fiber membrane The uniformity of drying in the longitudinal direction is reduced, shrinkage of the hollow fiber membranes is increased, and the quality fluctuation in the hollow fiber membrane bundle is increased, which is not preferable.

  In the present invention, the hollow fiber membrane bundle to be dried is preferably placed on a horizontally set table having a rotation function and dried while rotating. Moreover, it is a preferable embodiment that a plurality of the hollow fiber membrane bundles to be dried are radially arranged at equal intervals in a direction in which one end in the longitudinal direction is directed to the center of the rotary table. Due to this correspondence, the uniformity of drying of the hollow fiber membrane bundle to be dried including the longitudinal direction of the hollow fiber membrane bundle to be dried can be improved by a synergistic effect with the implementation items described later. According to this method, since it can arrange | position only by putting on a rotary table, the operation | work of arrangement | positioning of the to-be-dried hollow fiber membrane bundle to a dryer can be performed very simply and efficiently. Further, by rotating the table, the energy of the microwave irradiated to the hollow fiber membrane bundle to be dried can be made uniform, and the drying uniformity of the hollow fiber membrane bundle to be dried can be improved. The table is preferably dried while rotating at a rotation speed of 3 to 20 rpm. It is also possible to take a means such as adding a recess in the shape of the tray to the location of the tray on the table, or conversely, adding a protrusion that can fix the tray to identify the location of the tray and improve the workability of the arrangement. This is a preferred embodiment.

  The rotary table has a structure in which a plastic spacer having a thickness of 3 mm or more is installed on a metal rotary holder, and a tray is preferably installed on the spacer. The thickness of the spacer is more preferably 4 mm or more, and further preferably 5 mm or more. If the thickness of the plastic spacer is less than 3 mm, the microwave is reflected by the metal rotating holder that supports the plastic spacer, and the reflected microwave accelerates the drying of the hollow fiber membrane on the rotating holder side. Then, the uniformity of heating of the hollow fiber membrane bundle to be dried is lowered, and the effect of the present invention is lowered. The material of the plastic spacer is not limited and may be a general-purpose resin such as polypropylene or polyethylene terephthalate. However, from the viewpoint of heat resistance, polycarbonate, polysulfone resin, polyether ether ketone, polyphenylene sulfide, aramid Those made of so-called engineering plastics such as wholly aromatic polyesters are preferred. Polysulfone resin is more preferable. It is within the scope of the present invention to make the plastic including the rotating holder.

  The position of the rotary table in the present invention is preferably set so that the center of the hollow fiber membrane bundle to be dried installed in the dryer is near the center of the waveguide outlet of the microwave oscillator. In the case of a method in which a large number of hollow fiber membrane bundles to be dried are arranged on each tray, the center in the height direction of the hollow fiber membrane bundle block to be dried coincides with the vicinity of the center of the waveguide outlet of the microwave oscillator. It is good to set to.

  The above characteristics can be easily achieved by carrying out the drying method of the present invention. Although expressed as an effect of the sum of the constituent requirements of the drying method of the present invention, the contribution of the effect of selecting the material for the package and tray described above is significant.

  In the present invention, as described above, the outermost layer of the bundle of hollow fiber membranes in contact with the package and the hollow fiber membrane in the vicinity thereof are selected unless the material having the characteristics specified in the present invention is selected as the material of the package or tray. Therefore, the hollow fiber membranes on the outer periphery of the bundle of hollow fiber membranes must have the above characteristics. Here, the outer peripheral portion refers to a range of ¼ radius from the outer periphery in the circular cross section of the hollow fiber membrane bundle.

  Examples of the constituent material of the hollow fiber membrane bundle in the present invention include cellulose such as regenerated cellulose, cellulose acetate, and cellulose triacetate, polysulfone such as polysulfone and polyethersulfone, polyacrylonitrile, polymethyl methacrylate, and ethylene vinyl alcohol copolymer. Cellulose polymers and polysulfone polymers are preferred. Moreover, what consists of hydrophobic polymer containing a hydrophilic polymer is preferable. In particular, a system composed of a polysulfone-based resin containing polyvinylpyrrolidone is preferable because a selective permeable separation membrane having excellent biocompatibility and excellent water permeability and separation characteristics can be obtained.

Polysulfone resin is a generic term for resins having a sulfone bond, and is not particularly limited. For example, polysulfone resins and polyethersulfone resins having repeating units represented by chemical formulas 1 and 2 are widely available as polysulfone resins. It is preferable because it is easily available.

  Polyvinyl pyrrolidone is a water-soluble polymer compound obtained by vinyl polymerization of N-vinyl pyrrolidone. The product names are “Collidon” from BASF, “Prasdon” from ISP, and “Pittscall” from Daiichi Kogyo Seiyaku. There are products of various molecular weights that are commercially available. In general, it is preferable to use a low molecular weight in terms of imparting hydrophilicity, while a high molecular weight is preferable in terms of reducing the amount of elution, but in accordance with the required characteristics of the hollow fiber membrane bundle of the final product. It is selected appropriately. Those having a single molecular weight may be used, or two or more products having different molecular weights may be mixed and used. Moreover, you may use what refine | purified a commercial product and sharpened molecular weight distribution, for example. As the molecular weight of polyvinylpyrrolidone, those having a mass average molecular weight of 10,000 to 1,500,000 can be used. Specifically, for example, those having a molecular weight of 9,000 (K17) commercially available from BASF, and the same shall apply hereinafter, 45,000 (K30), 450,000 (K60), 900,000 (K80), 1,200 000 (K90) is preferable, and in order to obtain the intended use, characteristics, and structure, each may be used alone, or two or more may be used in combination as appropriate.

  The composition ratio of polyvinylpyrrolidone in the polysulfone-based resin in the present invention is not particularly limited as long as it is in a range capable of imparting sufficient hydrophilicity and high wettability to the hollow fiber membrane, but can be arbitrarily set, The mass ratio of polyvinylpyrrolidone to the polysulfone resin is preferably 1 to 20 mass%, more preferably 3 to 15 mass%. If it is less than 1% by mass, the hydrophilicity-imparting effect of the film may be insufficient. On the other hand, if it exceeds 20% by mass, the effect of imparting hydrophilicity is saturated, and the amount of elution from the membrane of the hydrophilic polymer increases, resulting in a decrease in safety.

  Although the manufacturing method of the hollow fiber membrane bundle in this invention is not limited at all, For example, the method which is known by Unexamined-Japanese-Patent No. 2000-300663 is illustrated. For example, 16% by mass of polyethersulfone (4800P, manufactured by Sumitomo Chemical Co., Ltd.), 5% by mass of polyvinylpyrrolidone (K-90, manufactured by BASF), 74% by mass of dimethylacetamide and 5% by mass of water were mixed and dissolved, and defoamed. As a spinning solution, 50% dimethylacetamide aqueous solution is used as the core solution, and this is simultaneously discharged from the outside and inside of the double tube orifice. A guided hollow fiber membrane bundle can be formed and scraped after washing with water to produce a wet hollow fiber membrane bundle.

  The above-described drying method in the present invention is a preferred embodiment that is applied to, for example, a wet state hollow fiber membrane bundle obtained by the above method or the like.

  In the present invention, as described above, it is possible to use a conventional ventilation method that allows the gas to pass through the hollow fiber membrane bundle and achieve uniform drying, but it is not necessary to use it. Can be performed by a simplified method, and various problems caused by the ventilation method can be improved, but the above-described hollow fiber membrane bundle obtained by the present invention has stable characteristics. In order to obtain it, it is preferable to incorporate means for achieving uniform drying of the hollow fiber membrane bundle in addition to the above-mentioned achievement requirements. Hereinafter, this measure will be mentioned.

  It is preferable to install a microwave oscillator on the side wall of the microwave irradiation oven and irradiate the microwave from the side surface direction of the rotary table. Further, a microwave oscillator in which the ratio (Er / Ei) of the energy Ei of the incident wave from the microwave oscillator toward the oven and the energy Er of the reflected wave reflected from the oven toward the oscillator is 0.2 or less is used. It is more preferable to heat by irradiating with microwaves. Measurement of the energy Ei of the incident wave from the microwave oscillator toward the oven and the energy Er of the reflected wave reflected from the oven toward the oscillator is performed by installing an energy detector in the waveguide section from the microwave oscillator toward the oven. Measured and obtained. When Er / Ei exceeds 0.2, the energy of the microwave hitting the hollow fiber membrane bundle becomes non-uniform, and the effects of the present invention can be fully exhibited even if various means for uniform heating described later are taken. You may not be able to. If Er / Ei is large, the magnetron of the oscillator may be destroyed by the reflected wave. Er / Ei is more preferably 0.15 or less, and further preferably 0.10 or less. In the present invention, the method for reducing the above Er / Ei to 0.1 or less is not limited, but it is a preferred embodiment to employ various measures disclosed in Japanese Patent Laid-Open No. 2000-340356.

  The above-mentioned correspondence and the arrangement of the hollow fiber membrane bundle to be dried make the intensity distribution of the microwaves irradiated to the hollow fiber membrane bundle to be dried uniform, and the drying of the hollow fiber membrane bundle is made uniform. The preferable characteristic which a hollow fiber membrane bundle should have can be provided.

  In the present invention, it is preferable to stop the microwave irradiation at the time when the water content in the hollow fiber membrane bundle is reduced to 10 to 20% by mass and subsequently dry by far infrared irradiation. The water content at the time of switching is more preferably 10 to 15% by mass. When drying by microwave irradiation until the water content is less than 10% by mass, the degradation of polyvinylpyrrolidone increases, the elution amount of hydrogen peroxide increases, and the storage stability of the hollow fiber membrane bundle may decrease. In addition, the moisture content in the longitudinal direction of the hollow fiber membrane bundle and the fluctuation rate of UV (220 to 350 nm) absorbance increase, which may increase the occurrence of partial fixation of the hollow fiber membrane bundle. Conversely, if microwave irradiation is stopped at a time when the moisture content is higher than 20% by mass, the total drying time until drying to the final moisture content becomes longer, which is uneconomical.

  Total drying is completed by drying with far-infrared irradiation after the above-described microwave irradiation in the present invention. It is preferable that the moisture content in the hollow fiber membrane bundle after completion of the drying is 1 to 7% by mass. Moreover, it is preferable that each moisture content fluctuation | variation rate is 10% or less when this dry hollow fiber membrane bundle is divided into 10 in the longitudinal direction and measured. By obtaining a dry hollow fiber membrane bundle having such a water content, the properties that the hollow fiber membrane bundle of the present invention must hold can be imparted. In addition, when the water content exceeds 10% by mass, bacteria during storage are likely to proliferate, the hollow fiber membrane is crushed due to its own weight, or an adhesive failure occurs during assembly of the module. there's a possibility that.

The moisture content of the hollow fiber membrane bundle in the present invention was calculated by the following formula.
Moisture content (mass%) = 100 × (Ww−Wd) / Wd
Here, Ww is the mass (g) of the hollow fiber membrane before drying, and Wd is the mass (g) of the hollow fiber membrane after being dried in a 120 ° C. dry heat oven for 2 hours (after absolutely dry). Here, by setting Ww within the range of 1 to 2 g, it can be in an absolutely dry state (a state in which there is no further weight change) after 2 hours.

  On the other hand, it is preferable to dry by microwave irradiation until the moisture content in the hollow fiber membrane bundle becomes 10 to 20% by mass. Microwave drying is known to be a useful method for drying a hollow fiber membrane bundle because it can be efficiently dried, but microwave irradiation is performed until the final moisture content reaches 1 to 7% by mass. If the drying is continued, the fluctuation of the degree of deterioration of polyvinyl pyrrolidone in the longitudinal direction and the fluctuation of the moisture content in the hollow fiber membrane will increase, and the hollow fiber membrane bundle having the above-mentioned characteristics of the present invention may not be obtained. There is sex. The cause of the deterioration of the polyvinyl pyrrolidone in the longitudinal direction of the hollow fiber membrane and the increase in fluctuations in the moisture content by irradiating microwaves with the moisture content of the hollow fiber membrane bundle being somewhat low has not been clarified. Contributing to the fact that drying is performed by direct excitation of water molecules, and that moisture in the hollow fiber membrane has a strong affinity for polyvinylpyrrolidone and is localized in the portion where polyvinylpyrrolidone exists It is guessed. That is, the localization of water increases as the water content decreases, heat generation in the portion where the water is localized increases, leads to uneven temperature and dryness of the hollow fiber membrane, and around the water molecule. It is presumed that deterioration is promoted due to the presence of polyvinylpyrrolidone. On the other hand, since far-infrared drying and the like have lower excitation energy than microwaves, it is considered that the occurrence of the above problems is suppressed.

  The water content management method is not limited. Online measurement may be performed by an infrared absorption method or the like, or offline measurement by sampling may be performed.

  In the present invention, as described above, it is important to suppress oxidative degradation of polyvinylpyrrolidone in the drying step. Therefore, it is preferable to carry out the above-described microwave irradiation or far-infrared irradiation in an inert gas atmosphere such as nitrogen gas, but it is economically disadvantageous. On the other hand, a method of suppressing oxidation deterioration by performing microwave drying or far-infrared drying under reduced pressure leads to an improvement in drying efficiency and is recommended. The most preferred embodiment is that both drying operations are performed under reduced pressure. For example, as a drying condition for microwave drying, it is preferable to irradiate microwaves with an output of 0.1 to 100 kW under a reduced pressure of 20 kPa or less. Moreover, the frequency of this microwave is 1,000-5,000 MHz, and it is a preferable embodiment that the highest ultimate temperature of the hollow fiber membrane bundle during a drying process is 90 degrees C or less. If it is used in combination with a means of reduced pressure, drying alone is accelerated, so there is an advantage that the microwave irradiation output can be kept low and the irradiation time can be shortened, but the temperature rise can also be made relatively low, so the whole In particular, the influence on the performance degradation of the hollow fiber membrane bundle is small. Furthermore, drying accompanied by means of reduced pressure has the advantage that the drying temperature can be relatively lowered, and has a significant point that deterioration and decomposition of the hydrophilic polymer can be remarkably suppressed. An appropriate drying temperature is sufficient from 20 to 80 ° C. More preferably, it is 20-60 degreeC, More preferably, it is 20-50 degreeC, More preferably, it is 30-40 degreeC.

  The fact that the pressure is reduced means that the low pressure acts uniformly on the central part and the outer peripheral part of the hollow fiber membrane bundle, the evaporation of moisture is promoted uniformly with low energy, and the hollow fiber membranes are dried. In order to be made uniform, the failure of the hollow fiber membrane bundle due to non-uniform drying is corrected. In addition, heating by microwaves also acts almost equally on the entire center and outer periphery of the hollow fiber membrane bundle, so it functions synergistically in uniform heating, and is unique in drying the hollow fiber membrane bundle. It will be of significance. The degree of vacuum may be set as appropriate depending on the output of the microwave, the total moisture content of the hollow fiber membrane bundle, and the number of hollow fiber membrane bundles, but the degree of vacuum is 20 kPa to prevent the temperature of the hollow fiber membrane bundle during drying. Hereinafter, it is performed more preferably at 15 kPa or less, and further preferably at 10 kPa or less. If it exceeds 20 kPa, not only the water evaporation efficiency is lowered, but also the temperature of the polymer forming the hollow fiber membrane bundle may be increased and deteriorated. Moreover, although the one where a pressure reduction degree is higher is preferable in the meaning which suppresses a temperature rise and raises drying efficiency, since the cost concerning maintaining the sealing degree of an apparatus becomes high, 0.1 kPa or more is preferable. More preferably, it is 0.2 kPa or more, More preferably, it is 0.3 kPa or more.

In consideration of shortening the drying time, a higher microwave output is preferable.For example, in hollow fiber membrane bundles containing polyvinylpyrrolidone, degradation or decomposition of polyvinylpyrrolidone occurs due to overdrying or overheating, and wettability decreases during use. Therefore, it is preferable not to increase the output so much. Further, the hollow fiber membrane bundle can be dried even with an output of less than 0.1 kW, but there is a possibility that a problem of reduction in throughput due to an increase in drying time may occur. The optimum value of the combination of the degree of decompression and the microwave output varies depending on the water content of the hollow fiber membrane bundle and the number of processed hollow fiber membrane bundles, and it is preferable to obtain a set value as appropriate through trial and error.
For example, as a temporary guide for carrying out the drying conditions of the present invention, when 20 hollow fiber membrane bundles having a moisture content of 50 g per hollow fiber membrane bundle are dried, the total moisture content is 50 g × 20 fibers = 1,000 g. At this time, it is appropriate that the microwave output is 1.5 kW and the decompression degree is 5 kPa.

  A more preferable microwave output is 0.1 to 80 kW, and a more preferable microwave output is 0.1 to 60 kW. The output of the microwave is determined by, for example, the total number of hollow fiber membranes and the total moisture content. However, if the microwave is suddenly irradiated, drying is completed in a short time, but the hollow fiber membrane is partially denatured. And may cause deformation such as curling. When drying using microwaves, for example, when using something like a water retention agent in the hollow fiber membrane, high power and extreme drying using microwaves will disappear due to scattering of the water retention agent It becomes the cause of. In consideration of the influence on the hollow fiber membrane, especially under conditions under reduced pressure, conventionally, irradiation with microwaves under reduced pressure was not intended. Irradiation of microwaves under reduced pressure according to the present invention means that the evaporation of aqueous liquid is active even in a relatively low temperature state, so that degradation of polyvinylpyrrolidone and deformation of hollow fiber membranes due to high output microwaves and high temperatures Thus, a double effect of preventing damage to the hollow fiber membrane is obtained.

  Although the present invention enables one-stage drying in which the microwave output is constant, i.e., drying by microwaves under reduced pressure, as another embodiment, the microwave output is sequentially changed according to the progress of drying. So-called multi-stage drying, which lowers in stages, is included as a preferred embodiment. Therefore, the significance of multi-stage drying will be described as follows. When drying with microwaves at a relatively low temperature of about 30 to 90 ° C. under reduced pressure, multi-stage drying in which the output of the microwaves is sequentially reduced in accordance with the progress of drying of the hollow fiber membrane bundle. The method is excellent. The degree of pressure reduction, temperature, microwave output, and irradiation time may be determined in consideration of the total amount of the hollow fiber membrane to be dried and the industrially acceptable drying time. Multistage drying can be performed in any number of stages, for example, 2 to 6 stages, but it is appropriate to use 2 to 3 stages of drying that is industrially appropriate in consideration of productivity. Depending on the total amount of water contained in the hollow fiber membrane bundle, when relatively large, multistage drying is performed at a temperature of 90 ° C. or lower, for example, at a reduced pressure of about 5 to 20 kPa, and the first stage is 30 to 100 kW. The range can be determined in consideration of the microwave irradiation time such that the second stage is in the range of 10 to 30 kW and the third stage is in the range of 0.1 to 10 kW. When the output of the microwave is large, such as 90 kW in the high part and 0.1 kW in the low part, the number of stages for reducing the output may be increased to 4 to 8 stages, for example. In the case of the present invention, since technical consideration is given to the microwave irradiation called decompression, there is an advantage that the microwave output can be relatively lowered. For example, the first stage is about 10 to 100 minutes by 10 to 20 kW microwave, the second stage is about 3 to 10 kW and about 5 to 80 minutes, and the third stage is about 0.1 to 3 kW and about 1 to 60 minutes. Dry in stages. It is preferable that the microwave output and irradiation time of each stage are lowered in conjunction with the reduction in the total amount of moisture contained in the hollow fiber membrane. Since this drying method is a very gentle drying method for hollow fiber membrane bundles and cannot be expected in the prior arts of Patent Documents 6 to 10 described above, the effect of the present invention is made significant.

  To explain another aspect, when the so-called moisture content of the hollow fiber membrane bundle is relatively small, that is, a so-called moisture content of 400% by mass or less, irradiation with a low output microwave of 12 kW or less may be excellent. For example, when the amount of water in the total amount of the hollow fiber membrane bundle is about 1 to 7 kg, the output is 12 kW or less under a reduced pressure of about 3 to 10 kPa at a temperature of 80 ° C. or less, preferably 60 ° C. or less. For example, irradiation with a microwave of about 1 to 5 kW for 10 to 240 minutes, irradiation with a microwave of less than 0.5 to 1 kW for about 3 to 240 minutes, and irradiation with a microwave of less than 0.1 to 0.5 kW for about 1 to 240 minutes If the irradiation output and the irradiation time of the microphone mouth wave are adjusted according to the degree of drying, drying is performed uniformly. The degree of vacuum is set to 0.1 to 20 kPa for each stage, but the first stage having a relatively high moisture content of the hollow fiber membrane is increased to 0.1 to 5 kPa, for example, and the microwave output is increased. The degree of pressure reduction at each stage, in which the microwave is irradiated with a slightly lower pressure and output than the first stage of 0.1 to 5 kW under a reduced pressure of 5 to 20 kPa in the second and third stages. It is possible to arbitrarily set the change by appropriately adjusting depending on the situation in consideration of the transition of the decrease in the total moisture content and moisture content of the hollow fiber membrane bundle. In each stage, the operation of changing the degree of reduced pressure further increases the significance of irradiating microwaves under reduced pressure according to the present invention. Of course, it is necessary to always consider the uniform irradiation and exhaust of the microwave in the microwave irradiation apparatus.

  The maximum temperature reached by the hollow fiber membrane bundle during drying can be measured by attaching an irreversible thermolabel to the side surface of the hollow fiber membrane bundle package, drying, and taking out the dried display and confirming the display. At this time, the maximum reached temperature of the hollow fiber membrane bundle during drying is preferably 90 ° C. or lower, more preferably 80 ° C. or lower. More preferably, it is 70 degrees C or less. If the maximum temperature reaches 90 ° C. or higher, the film structure is likely to change, which may cause performance degradation or oxidative degradation. In particular, in a hollow fiber membrane bundle containing polyvinylpyrrolidone, it is necessary to prevent the temperature rise as much as possible because polyvinylpyrrolidone is easily decomposed by heat. Temperature rise can be prevented by optimizing the degree of decompression and microwave output and irradiating intermittently. Moreover, although the one where a drying temperature is lower is preferable, 30 degreeC or more is preferable from the surface of the maintenance cost of pressure reduction degree, and the shortening of drying time.

  The microwave irradiation frequency is preferably 1,000 to 5,000 MHz in consideration of the suppression of irradiation spots on the hollow fiber membrane bundle and the effect of extruding water in the pores from the pores. More preferably, it is 1,500-4,000 MHz, More preferably, it is 2,000-3,000 MHz.

  In drying by microwave irradiation, it is important to uniformly heat and dry the hollow fiber membrane bundle. In the above-described microwave drying, nonuniform heating due to the reflected wave that occurs accompanying the generation of the microwave occurs, so it is important to take measures to reduce the nonuniform heating due to the reflected wave. The method is not limited and is arbitrary. For example, a method of providing a reflector in an oven disclosed in Japanese Patent Application Laid-Open No. 2000-340356 to reflect reflected waves and uniformize heating is a preferred embodiment. One.

  On the other hand, in the case of drying by far-infrared irradiation performed after the completion of microwave drying, unlike the case of microwave drying, the discharge phenomenon does not occur even if irradiation is performed under reduced pressure. It can be carried out. From the point of drying efficiency, 2 kPa or less is preferable and 1 kPa or less is more preferable. The irradiation energy of the far-infrared irradiation is preferably controlled so as to be 80 ° C. or lower at a temperature detected by a thermocouple provided at the center of the oven. It is more preferable to control at 70 ° C. or lower.

  The far-infrared irradiation may be started after the end of microwave irradiation, or may be performed at the time of microwave irradiation, and microwave drying and far-infrared drying may be performed simultaneously. By performing the microwave and far infrared irradiation simultaneously, the evaporation of water that has been excited by the microwave irradiation and moved to the surface of the hollow fiber membrane is accelerated by the far infrared irradiation, leading to an improvement in drying efficiency. Further, this efficient evaporation of the surface moisture is preferable because the variation in the concentration of polyvinylpyrrolidone on the surface of the hollow fiber membrane induced by the surface moisture is suppressed, and the occurrence of partial sticking is suppressed. As described above, microwave drying is preferably performed under reduced pressure. Therefore, microwave drying and far-infrared drying are simultaneously performed under reduced pressure, and microwave irradiation is performed when the moisture content is reached. A method of stopping drying by continuing far-infrared irradiation while maintaining a reduced pressure state and continuing further drying is more preferable. At that time, after the microwave irradiation is completed, the degree of decompression of the system may be lowered, and after conditioning, the degree of decompression may be raised again to start far-infrared irradiation. Therefore, in the present invention, it is a preferred embodiment that drying is performed using a microwave dryer in which a far-infrared heater is attached in the heating oven and an exhaust system capable of reducing the pressure of the heating oven is attached.

  In this invention, it is preferable that the irradiation wavelength of a far infrared ray is 1-30 micrometers. Water and organic matter have a high absorption rate for far-infrared rays with a wavelength of 3 to 12 μm. Therefore, if the far-infrared wavelength is too short or too long, it is difficult to increase the temperature of the water. May increase. Therefore, the wavelength of the far infrared ray to be irradiated is more preferably 1.5 to 26 μm, further preferably 2 to 22 μm, and further preferably 2.5 to 18 μm.

In the present invention, as a radiation medium for irradiating far-infrared rays, a stainless steel medium having a metal oxide film on the surface is preferably used. For example, an austenitic stainless steel powder as described in JP-A-10-5265 is coated with a metal oxide such as Al ₂ O ₃ , Fe ₂ O ₃ , TiO ₂ , CaO, MgO, K ₂ O and Na ₂ O. It is a more preferable embodiment to use a far-infrared radiator coated with, because far-infrared rays can be extracted efficiently at low cost.

  On the other hand, in the case of drying by far-infrared irradiation performed after the completion of microwave drying, unlike the case of microwave drying, the discharge phenomenon does not occur even if irradiation is performed under reduced pressure. It can be carried out. From the point of drying efficiency, 5 kPa or less is preferable, 4 kPa or less is more preferable, 3 kPa or less is more preferable, and 2 kPa or less is more preferable. The irradiation energy of the far-infrared irradiation is preferably controlled so as to be 80 ° C. or lower at a temperature detected by a thermocouple provided at the center of the oven. It is more preferable to control at 70 ° C. or lower.

  In the present invention, it is a preferred embodiment that an inert gas such as nitrogen gas is used when the inside of the drying system is returned to normal pressure after drying. Immediately after the drying, the temperature of the hollow fiber membrane bundle is high, so when returning the inside of the drying chamber to atmospheric pressure, when a gas containing oxygen such as air is fed, in the case of a hollow fiber membrane containing polyvinylpyrrolidone, polyvinylpyrrolidone May undergo oxidative degradation due to the effects of oxygen and heat. Therefore, when the inside of the drying chamber is returned to normal pressure after the drying is completed, the oxidative deterioration of the polyvinyl pyrrolidone in the hollow fiber membrane bundle is suppressed by feeding the inert gas.

  For the drying of the hollow fiber membrane bundle, the use of microwaves and far-infrared rays for an unlimited time does not affect the quality. This is because the effects of thermal degradation of the hydrophobic polymer or the hydrophilic polymer material constituting the hollow fiber membrane bundle and environmental degradation such as oxygen, water, and steam can be considered. Therefore, from the viewpoint of industrial production, it is necessary to consider an appropriate time that is naturally allowed for the drying time. From the viewpoint of protecting the quality of the hollow fiber membrane subjected to relatively harsh drying conditions such as microwaves and far infrared rays, from the viewpoint of industrial productivity, the inventors of the present invention are from the start to the end of drying. The drying time is preferably within 3 hours. More preferably within 2.5 hours, still more preferably within 2 hours.

  The appropriate drying time of the hollow fiber membrane bundle is a value obtained by adding a drying region by far infrared rays to a drying region time by microwave, of course, in this case, a drying means using both may be included, The present inventors have analyzed the behavior of whether the switching state between the drying region time by the microwave and the drying region by the far infrared ray is most dependent on the technical conditions. If it demonstrates based on FIG. 1, if it dries within the range enclosed by the area | region enclosed with 1 and 2 of a continuous line, it is that a product with comparatively good quality is easily obtained. For example, if it becomes the area | region of the broken lines (1) and (2) of FIG. 1, it will have a considerable influence on the quality of a hollow fiber membrane bundle. This can be easily understood by taking into account the statistical interpretation shown in FIG.

  Looking closely at such an analysis, as a method of drying a hollow fiber membrane having a relatively high moisture content, microwave drying is optimal in this case, microwave drying under reduced pressure is suitable for it, It can also be said that the drying by far-infrared including conditioning is appropriate drying. As a result of examination by the inventors about this switching, the moisture content of the hollow fiber membrane bundle is 5 to 30% by mass, preferably 8 to 25% by mass, more preferably 10 to 20% by mass by drying with microwaves. The fact that it is best to switch at the stage reached is found.

  For example, when the moisture content of the hollow fiber membrane bundle is 60 to 400% by mass, it is forcibly reduced to a predetermined moisture content by applying a reduced pressure by a microwave in some cases, and then far infrared rays are used together. The present inventors have found that the method is most suitable. The appropriate range of 10 to 20% by mass of water content is slightly different depending on the polymer material, structure, etc., but within this range, it can be said that it can be applied to drying of general-purpose hollow fiber membrane bundles.

  FIG. 2 shows an analysis of an example in which the range of 10 to 20% by mass of the dry switching affects the quality of the hollow fiber membrane bundle. Based on Examples and Comparative Examples, several examples are plotted. It can be easily understood that this tendency influences the variation of the hollow fiber membrane bundle, with the water content of the hollow fiber membrane bundle being 10 to 20% by mass as a boundary. The idea of using far-infrared rays in combination with microwaves is based on the knowledge of the present inventors. This is based on the knowledge of the present inventors and is a new idea.

  In the hollow fiber membrane bundle according to the present invention, it is preferable that the elution amount of hydrogen peroxide is suppressed as described above. Regarding the provision of this property, it is important to select the drying method and conditions described above, but the quality and handling of polyvinyl pyrrolidone, the causative agent of hydrogen peroxide generation, are also important factors and considerations are required. is necessary. For example, it is preferable to produce using polyvinyl pyrrolidone having a hydrogen peroxide content of 300 ppm or less. By making the hydrogen peroxide content in the polyvinylpyrrolidone used as a raw material 300 ppm or less, the hydrogen peroxide elution amount of the hollow fiber membrane bundle after film formation can be easily suppressed to 5 ppm or less. This is preferable because the quality of the yarn membrane bundle can be stabilized. Therefore, the hydrogen peroxide content in the polyvinyl pyrrolidone used as a raw material is more preferably 250 ppm or less, further preferably 200 ppm or less, and further preferably 150 ppm or less.

  It is estimated that hydrogen peroxide contained in polyvinylpyrrolidone used as the raw material is generated in the process of oxidative degradation of polyvinylpyrrolidone. Therefore, to reduce the hydrogen peroxide content to 300 ppm or less, it is effective to take measures to suppress the oxidative degradation of polyvinylpyrrolidone in the production process of polyvinylpyrrolidone. It is also effective and recommended to take measures to suppress deterioration during transportation and storage of polyvinylpyrrolidone. For example, it is preferable to use an aluminum foil laminated bag to shield the light and enclose it with an inert gas such as nitrogen gas, or to enclose and store an oxygen scavenger together. In addition, it is preferable that the measurement and preparation when the package is opened and subdivided be performed after inert gas replacement, and the above-mentioned measures are taken for the storage. Also, in the manufacturing process of the hollow fiber membrane bundle, it is also recommended as a preferred embodiment to take a means such as replacing the supply tank or the like in the raw material supply system with an inert gas. In addition, it is not excluded to take a method of reducing the amount of hydrogen peroxide by a recrystallization method or an extraction method.

  Also, when stirring and dissolving a spinning solution composed of a polysulfone resin, polyvinyl pyrrolidone, and a solvent, if hydrogen peroxide is contained in the polyvinyl pyrrolidone, the influence of oxygen present in the dissolution tank and the heating during dissolution It was found that hydrogen peroxide increased explosively due to the influence. Therefore, when charging the raw material into the dissolution tank, it is preferable to input the raw material into the dissolution tank that has been previously replaced with an inert gas. As the inert gas, nitrogen, argon or the like is preferably used. Moreover, although a solvent, and a non-solvent may be added depending on the case, it is also a preferable embodiment that oxygen dissolved in these solvent and non-solvent is replaced with an inert gas.

  As a method for controlling the elution amount of hydrogen peroxide to the above regulated range, for example, as described above, it is effective to make the amount of hydrogen peroxide in polyvinylpyrrolidone used as a raw material 300 ppm or less. Since the hydrogen peroxide is also generated during the manufacturing process of the hollow fiber membrane described above, it is necessary to strictly control the manufacturing conditions of the hollow fiber membrane. In particular, since the contribution of the production in the drying process when producing the hollow fiber membrane is large, it is important to optimize the drying conditions. In particular, the optimization of the drying conditions is important because it greatly contributes to the suppression of hydrogen peroxide production. Furthermore, the optimization of the drying conditions is an effective means for reducing the fluctuation in the elution amount in the longitudinal direction of the hollow fiber membrane.

  In addition, as another method for suppressing the generation of hydrogen peroxide, it is an important requirement to dissolve the film forming solution in a short time. For this purpose, it is usually sufficient to increase the dissolution temperature and / or increase the stirring speed. However, when it does so, degradation and decomposition of polyvinyl pyrrolidone will proceed due to the influence of temperature, stirring linear velocity and shearing force. In fact, according to the study by the inventors, the molecular weight of polyvinylpyrrolidone in the film-forming solution is shifted to the low molecular side as the dissolution temperature increases, or the decomposition product is present on the low molecular side. The phenomenon that the shoulder which seems to appear appears. From the above, increasing the temperature for the purpose of improving the dissolution rate of the raw material accelerates the degradation and degradation of polyvinylpyrrolidone, and consequently blends the degradation product of polyvinylpyrrolidone into the selectively permeable separation membrane. When the obtained hollow fiber membrane was used for blood purification, degradation products were eluted in the blood, so that it was not excellent in terms of product quality safety. Then, it tried to mix a raw material at low temperature in order to suppress decomposition | disassembly of polyvinylpyrrolidone. Even if it is low-temperature dissolution, it is usually preferable to have a temperature of 5 ° C. or higher and 70 ° C. or lower because it requires a running cost under extreme conditions that are below freezing. 60 degrees C or less is more preferable. However, simply lowering the melting temperature causes degradation of polyvinylpyrrolidone due to the longer melting time, lowering the operability and increasing the size of the equipment, which causes problems in industrial implementation.

  As a result of examining the dissolution conditions for dissolving at low temperature without taking time, it was found that it is preferable to knead the components constituting the spinning solution prior to dissolution, and the present invention was reached. The kneading may be performed by kneading components such as polysulfone polymer, polyvinyl pyrrolidone and a solvent at once, or kneading polyvinyl pyrrolidone and polysulfone polymer separately. As mentioned above, polyvinylpyrrolidone is accelerated by contact with oxygen and leads to the generation of hydrogen peroxide. Therefore, consideration must be given to suppressing contact with oxygen, such as in an atmosphere substituted with an inert gas, even during kneading. It is preferable to carry out in a separate line. A method of supplying only the polyvinyl pyrrolidone and the solvent and supplying the polysulfone polymer directly to the dissolution tank without pre-kneading is also included in the scope of the present invention.

  The kneading may be performed by providing a kneading line separately from the dissolving tank, and the kneaded product may be supplied to the dissolving tank, or both the kneading and dissolving may be performed in a dissolving tank having a kneading function. The type and form of the kneading apparatus in the former separate apparatus are not limited. Either a batch system or a continuous system may be used. A static method such as a static mixer may be used, or a dynamic method such as a kneader or a stirring kneader may be used. The latter is preferred from the efficiency of kneading. The kneading method in the latter case is not limited, and any type such as a pin type, a screw type, and a stirrer type may be used. Screw type is preferred. What is necessary is just to select suitably the shape and rotation speed of a screw from the balance of kneading | mixing efficiency and heat_generation | fever. On the other hand, the type of dissolution tank when using a dissolution tank having a kneading function is not limited. For example, there is a kneading and dissolving machine of a type that expresses a kneading effect by so-called planetary motion in which two frame-type blades rotate and revolve. Recommended. For example, a planetary mixer or a trimix manufactured by Inoue Seisakusho Co., Ltd. corresponds to this method.

  The ratio of the resin component such as polyvinyl pyrrolidone or polysulfone polymer and the solvent during kneading is not limited. A resin / solvent mass ratio of 0.1 to 3 is preferred. 0.5-2 are more preferable.

  As described above, the technical point of the present invention is to suppress the degradation of polyvinyl pyrrolidone and perform efficient dissolution. Therefore, a system in which at least polyvinylpyrrolidone is present is a preferred embodiment in which the system is kneaded and dissolved at a low temperature of 70 ° C. or lower in a nitrogen atmosphere. When the polyvinyl pyrrolidone and the polysulfone polymer are kneaded in separate lines, this requirement may be applied to the polysulfone polymer kneading line. The efficiency of kneading and dissolution and heat generation are two contradictory phenomena. Selection of an apparatus and conditions that avoid the trade-off as much as possible is an important element of the present invention. In this sense, the cooling method in the kneading mechanism is important and needs attention.

Subsequently, the material kneaded by the above method is dissolved. Although the dissolution method is not limited, for example, a dissolution method using a stirring type dissolution apparatus can be applied. In order to dissolve at a low temperature for a short time (within 3 hours), the Froude number (Fr = n ² d / g) is 0.7 to 1.3 and the stirring Reynolds number (Re = nd ² ρ / μ) is It is preferable that they are 50 or more and 250 or less. Here, n is the blade rotation speed (rps), ρ is the density (Kg / m ³ ), μ is the viscosity (Pa · s), g is the gravitational acceleration (= 9.8 m / s ² ), and d is the stirring blade diameter. (M). If the Froude number is too large, the inertial force becomes strong, so that the raw material scattered in the tank adheres to the walls and ceiling, and the desired film-forming solution composition may not be obtained. Therefore, the fluid number is more preferably 1.25 or less, further preferably 1.2 or less, and further preferably 1.15 or less. On the other hand, if the fluid number is too small, the inertial force is weakened, so that the dispersibility of the raw material is lowered, and in particular, polyvinylpyrrolidone becomes a spatter, which makes it difficult to dissolve further or requires a long time for uniform dissolution. Sometimes. Therefore, the fluid number is more preferably 0.75 or more, and further preferably 0.8 or more.

  Since the film-forming solution in the present invention is a so-called low-viscosity fluid, if the stirring Reynolds number is too large, the defoaming time becomes long due to entrapment of bubbles in the film-forming solution during stirring, or the defoaming is insufficient. Problems may occur. Therefore, the stirring Reynolds number is more preferably 240 or less, further preferably 230 or less, and still more preferably 220 or less. On the other hand, when the stirring Reynolds number is too small, the stirring force becomes small, so that dissolution may be easily made nonuniform. Therefore, the stirring Reynolds number is more preferably 35 or more, further preferably 40 or more, still more preferably 55 or more, and particularly preferably 60 or more. Further, when a hollow fiber membrane is formed with such a spinning solution, the operation is deteriorated due to a decrease in spinnability due to bubbles, and in terms of quality, the portion becomes defective due to the entrapment of bubbles in the hollow fiber membrane, and the membrane is not confidential. It has been found that this causes problems such as decreased sex and burst pressure. Defoaming of the spinning solution is an effective countermeasure, but it may involve a change in the composition of the spinning solution due to viscosity control of the spinning solution or evaporation of the solvent.

Furthermore, since polyvinylpyrrolidone tends to undergo oxidative degradation due to the influence of oxygen in the air, it is preferable to dissolve the spinning solution in an inert gas enclosure. Nitrogen, argon, etc. are raised as the inert gas, but nitrogen is preferably used. At this time, the residual oxygen concentration in the dissolution tank is preferably 3% or less. If the nitrogen filling pressure is increased, the melting time can be shortened. However, in order to increase the pressure, the equipment cost is increased, and from the viewpoint of work safety, atmospheric pressure and 2 kgf / cm ² or less are preferable.

  In addition, as the shape of the stirring blade used for dissolving the low-viscosity film forming solution used in the present invention, a radial turbine blade such as a disk turbine type, a paddle type, a curved blade fan turbine type, an arrow blade turbine type, or a propeller type An axial-flow type wing such as an inclined paddle type or a fiddler type is included, but is not limited thereto.

  By using the low-temperature dissolution method as described above, it is possible to obtain a highly safe hollow fiber membrane in which the degradation degradation of the hydrophilic polymer is suppressed. In addition, it is preferable to use a spinning solution having a residence time of 24 hours or less after dissolution of the raw material for film formation. This is because thermal energy was accumulated while the film forming solution was kept warm, and a tendency to cause deterioration of the raw material was recognized.

  As a method for imparting the above properties, for example, the composition ratio of polyvinyl pyrrolidone with respect to the polysulfone-based polymer can be set to the above range, or the film forming conditions of the hollow fiber membrane bundle can be optimized. It is also an effective method to wash the formed hollow fiber membrane bundle. As film forming conditions, humidity adjustment of the air gap part at the nozzle outlet, stretching conditions, temperature of the coagulation bath, optimization of the composition ratio of the solvent and the non-solvent in the coagulation liquid, etc. Washing, alcohol washing, centrifugal washing and the like are effective. Among these methods, as the film forming conditions, optimization of the humidity of the air gap and the composition ratio of the solvent and the non-solvent in the external coagulating liquid is particularly effective as the cleaning method.

  As the internal coagulation liquid, a 0 to 80% by mass dimethylacetamide (DMAc) aqueous solution is preferable. More preferably, it is 15-70 mass%, More preferably, it is 25-60 mass%, More preferably, it is 30-50 mass%. If the concentration of the internal coagulation solution is too low, the dense layer of the blood contact surface becomes thick, which may reduce the solute permeability. On the other hand, if the concentration of the internal coagulating liquid is too high, the formation of the dense layer tends to be incomplete, and the fractionation characteristics may be deteriorated. The external coagulation liquid is preferably a 0 to 50% by weight DMAc aqueous solution. If the concentration of the external coagulation solution is too high, the outer surface open area ratio and outer surface average pore area will become too large, which may increase the backflow of endotoxin to the blood side during dialysis and decrease the burst pressure. is there. Therefore, the external coagulation liquid concentration is more preferably 40% by mass or less, further preferably 30% by mass or less, and still more preferably 25% by mass or less. If the concentration of the external coagulation liquid is too low, it is necessary to use a large amount of water to dilute the solvent brought in from the spinning solution, and the cost for waste liquid treatment increases. Therefore, the lower limit of the external coagulation liquid concentration is more preferably 5% by mass or more.

  In the production of the hollow fiber membrane bundle, it is preferable that stretching is not substantially performed before the hollow fiber membrane bundle structure is completely fixed. “Substantially no stretching” means that the roller speed during the spinning process is controlled so that the spinning solution discharged from the nozzle does not become slack or excessively tensioned. The discharge linear speed / coagulation bath first roller speed ratio (draft ratio) is preferably in the range of 0.7 to 1.8. If the ratio is less than 0.7, the running hollow fiber membrane bundle may be slack and lead to a decrease in productivity. Therefore, the draft ratio is more preferably 0.8 or more, more preferably 0.9 or more, and 0 .95 or more is even more preferable. If it exceeds 1.8, the membrane structure may be destroyed, for example, the dense layer of the hollow fiber membrane bundle is torn. Therefore, the draft ratio is more preferably 1.7 or less, still more preferably 1.6 or less, still more preferably 1.5 or less, and particularly preferably 1.4 or less. By adjusting the draft ratio to this range, deformation and destruction of the pores can be prevented, clogging of blood protein into the membrane pores can be prevented, and performance stability over time and sharp fractionation characteristics can be expressed. Is possible.

The hollow fiber membrane bundle that has passed through the water-washing bath is wound into a basket in a wet state to form a bundle of 3,000 to 20,000. Next, the obtained hollow fiber membrane bundle is washed to remove excess solvent, polyvinylpyrrolidone. As a method for washing the hollow fiber membrane bundle, in the present invention, it is preferable to treat the hollow fiber membrane bundle by immersing it in hot water at 70 to 130 ° C. or room temperature to 50 ° C. and 10 to 40 vol% ethanol or isopropanol aqueous solution. .
(1) In the case of hot water washing, the hollow fiber membrane bundle is immersed in excess RO water and treated at 70 to 90 ° C. for 15 to 60 minutes, and then the hollow fiber membrane bundle is taken out and subjected to centrifugal dehydration. This operation is repeated three or four times while updating the RO water to perform the cleaning process.
(2) A method of treating a hollow fiber membrane bundle immersed in excess RO water in a pressurized container at 121 ° C. for about 2 hours may be employed.
(3) When using an ethanol or isopropanol aqueous solution, it is preferable to repeat the same operation as in (1).
(4) It is also a preferable washing method that the hollow fiber membrane bundle is radially arranged in the centrifugal washer, and centrifugal washing is performed for 30 minutes to 5 hours while spraying washing water at 40 ° C. to 90 ° C. from the rotation center in a shower shape. .
Two or more cleaning methods may be combined. In any of the methods, if the processing temperature is too low, it is necessary to increase the number of times of cleaning, which may lead to an increase in cost. On the other hand, if the treatment temperature is too high, the decomposition of polyvinylpyrrolidone is accelerated, and conversely, the cleaning efficiency may be reduced. By performing the above-described cleaning, it is possible to optimize the content of the outer surface polyvinyl pyrrolidone, thereby suppressing sticking and reducing the amount of eluate.

  In this invention, it is preferable that the content rate in the outer surface of the hollow fiber membrane of a hydrophilic polymer is 25-50 mass%. When the content of the hydrophilic polymer on the outer surface is less than 25% by mass, the content of the hydrophilic polymer on the entire membrane, particularly the inner surface of the membrane, becomes too low, and blood compatibility and permeation performance may decrease. . In the case of a dry film, wettability may be reduced. When the hemodialyzer is used for blood purification therapy, it is necessary to perform wetting and defoaming by allowing physiological saline or the like to flow inside and outside the hollow fiber membrane of the hemodialyzer. In this priming operation, roundness of the hollow fiber membrane, edge crushing, deformation, hydrophilicity of the membrane material, etc. are thought to affect the priming properties, but it consists of a hydrophobic polymer and a hydrophilic polymer. In the case of a hollow fiber membrane and a dry membrane module, the hydrophilic / hydrophobic balance of the hollow fiber membrane greatly affects the priming property. Therefore, the more preferable content of the hydrophilic polymer is 27% by mass or more, and more preferably 30% by mass or more. If the content of the hydrophilic polymer on the outer surface exceeds 50% by mass, the endotoxin (endotoxin) contained in the dialysate may enter the blood side, leading to side effects such as fever, When the membrane is dried, a hydrophilic polymer existing on the outer surface of the membrane is interposed, and the hollow fiber membranes stick to each other (adhere), which may cause problems such as deterioration in module assembly. Therefore, a more preferable content rate is 47 mass% or less, More preferably, it is 45 mass% or less.

  In addition, the content rate of the above-mentioned hydrophilic polymer surface outermost layer of the hydrophilic polymer was measured and calculated by the ESCA method as described later, and the outermost layer portion (depth number from the surface layer) on the surface of the hollow fiber membrane. The absolute value of the content ratio of ˜several tens of liters) is obtained. Usually, the ESCA method (outermost layer) can measure the content of hydrophilic polymer (PVP) up to a depth of about 10 nm (100 mm) from the blood contact surface.

  Moreover, in this invention, it is effective in order to provide an above described property that the porosity of the outer surface of a hollow fiber membrane is 8-25%, and is a preferable embodiment. If the open area ratio is less than 8%, the water permeability may be lowered. Further, when the membrane is dried, the hydrophilic polymer existing on the outer surface of the membrane is interposed, and the hollow fiber membranes are fixed to each other, causing problems such as deterioration in module assemblability. Therefore, the open area ratio is more preferably 9% or more, and further preferably 10% or more. On the other hand, when the open area ratio exceeds 25%, the burst pressure may decrease or endotoxin from the dialysate side to the blood side may enter during hemodialysis. Therefore, the porosity is more preferably 23% or less, further preferably 20% or less, still more preferably 17% or less, and particularly preferably 15% or less.

  The film thickness of the hollow fiber membrane is preferably 10 μm or more and 60 μm or less. If it exceeds 60 μm, the permeability of medium to high molecular weight substances having a low movement speed may be lowered even if the water permeability is high. The thinner the film thickness is, the higher the substance permeability is, and it is more preferably 55 μm or less, further preferably 50 μm or less, and still more preferably 47 μm or less. On the other hand, when the film thickness is less than 10 μm, the burst pressure may be lowered even if the film strength is low and the thickness deviation is 0.6 or more. Therefore, the film thickness is more preferably 20 μm or more, further preferably 25 μm or more, still more preferably 30 μm or more, and particularly preferably 35 μm or more.

  The hollow fiber membrane bundle of the present invention has the above-described characteristics and can be suitably used, for example, as a separation membrane of a separation module.

  The separation module of the present invention is a module in which both ends of a hollow fiber membrane bundle made of a polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin.

The shape of the separation module is illustrated in FIG.
The separation module 1 is loaded with a hollow fiber membrane bundle 3 in a cylindrical container 2, and both ends of the hollow fiber membrane bundle 3 are fixed to both ends of the container 2 with an adhesive or the like 4. Is covered with caps 5a and 5b. A dialysate inlet 6a for introducing dialysate into the container 2 is provided near one end of the side of the container 2, and a dialysate outlet 6b for discharging dialysate is provided near the other end. Each is formed to protrude. One cap 5a is formed with a blood introduction port 7a for introducing blood into the container 2, and the other cap 5b is formed with a blood discharge port 7b for discharging blood.

  The blood enters the space formed by the cap 5a and one end surface of the hollow fiber membrane bundle 3 from the blood introduction port 7a as indicated by the arrow A, and the hollow fiber membrane of the hollow fiber membrane bundle 3 is hollow. Passes through the part, enters the space formed by the other end face of the hollow fiber membrane bundle 3 and the cap 5b, and is discharged from the blood outlet 7b as shown by the arrow B. On the other hand, the dialysate enters the container 2 from the dialysate inlet 6a as shown by the arrow C, flows outside the hollow fiber membrane of the hollow fiber membrane bundle 3, and as shown by the arrow D, the dialysate outlet. It is discharged from 6b. At this time, the flow of blood to be dialyzed and the flow of dialysate are so-called opposite flows in opposite directions. During this time, waste in the blood flowing in the hollow fiber membrane is dialyzed into the outer dialysate through the hollow fiber membrane.

  Examples of the material for the container and the cap include polycarbonate, polyester, and polypropylene. Moreover, polyurethane etc. are mentioned as a material of the adhesive agent used for both ends fixing.

  The method of injecting the adhesive used for fixing both ends into the fixing portion is not limited, but a centrifugal bonding method is recommended in which injection is performed using the centrifugal force generated by rotating the module to be injected. The method of the centrifugal bonding method is not limited. For example, sealing jigs are attached to both ends of a container in which a dried hollow fiber membrane bundle is loaded, and set in a centrifugal bonding machine. A predetermined amount of uncured adhesive resin is injected from the dialysate inlets 6a and 6b at a temperature near room temperature while rotating the centrifugal adhesive machine at a predetermined rotational speed, and then the temperature of the centrifugal adhesive machine is injected. The curing temperature is raised and the curing is terminated, or at least the resin is precured until the fluidity of the resin is lost, and the centrifugal bonding machine is stopped. In the latter case, post-curing is performed to complete the curing. Moreover, the injection of the adhesive may be carried out in two or more times.

In the case of the centrifugal bonding method, it is important that the adhesive is uniformly injected into the entire space in the hollow fiber membrane bundle. If this injection becomes non-uniform and a part where the injection amount of the adhesive is insufficient is produced, it leads to poor adhesion. In particular, if there is a portion where the hollow fiber membranes are fixed, penetration of the adhesive is inhibited. Therefore, in order to unravel the adhering portion, for example, so-called yarn trimming treatment in which air is blown from the nozzle onto the end surface of the hollow fiber membrane bundle is performed. Certainly, the present yarn setting treatment is effective for unraveling the fixed hollow fiber membrane, but this treatment is not preferable because the hollow fiber membrane bundle at the end face portion is deformed and the inclined hollow fiber membrane is generated.
The hollow fiber membrane bundle of the present invention is characterized in that the uniformity of the injection of the adhesive is ensured without performing the yarn setting treatment because partial adhesion during drying is suppressed. Therefore, the yarn setting process is not necessary.
However, since it is important to ensure the uniformity of the injection of the adhesive, it is preferable to implement the following measures. For example, it is preferable to select a low viscosity brand as the adhesive. The viscosity after 2 minutes of mixing the two liquids is preferably 2000 mPa · s or less. 1600 mPa · s or less is more preferable. Moreover, it is preferable to lower the packing density of the hollow fiber membrane bundle restrained by the hollow package when the dry hollow fiber membrane bundle is inserted into the container used for module assembly.

  The number of hollow fiber membranes and the length of the hollow fiber membrane bundle to be filled are appropriately set according to market requirements and hollow fiber membrane bundle characteristics. The length and diameter of the container are set so as to match the size of the hollow fiber membrane bundle to be filled. The hollow fiber membrane bundle of the present invention described above is preferably used as the hollow fiber membrane bundle to be filled.

  The separation module of the present invention is a separation module in which both ends of a hollow fiber membrane bundle made of a polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin. (1) A hollow portion of a portion fixed with a resin evaluated by the following method The ratio of the number of hollow fiber membranes having a degree of inclination of the yarn membrane of 15 degrees or more is 0.05% or less, and (2) the ratio of the number of clogged hollow fiber membranes measured by the following method is 0.05% or less. It is preferable to satisfy simultaneously.

  When the inclination of the hollow fiber membrane bundle exceeds 15 degrees, blood becomes difficult to flow, and drift occurs, leading to the generation of residual blood hollow fiber membranes. The proportion of the inclined hollow fiber membrane is more preferably 0.04% or less, and further preferably 0.03% or less. 0% is particularly preferred. If it exceeds 0.05%, the number of residual blood hollow fiber membranes increases, which causes anxiety to dialysis patients. In the present invention, it is preferable that this characteristic is satisfied on both end faces.

  The ratio of the clogged hollow fiber membrane is more preferably 0.04% or less, and further preferably 0.03% or less. 0% is particularly preferred. When the ratio of the clogged hollow fiber membrane exceeds 0.05%, it is not preferable because blood becomes difficult to flow, blood drifts and leads to the generation of a residual blood hollow fiber membrane. In the present invention, it is preferable that this characteristic is satisfied on both end faces.

  Further, in the separation module of the present invention, the ratio of the number of crushed hollow fiber membranes evaluated by observing and evaluating the outermost surface portion of the portion where the hollow fiber membrane bundle on the module end surface is fixed with an adhesive is 0.05. % Or less is preferable. In the present invention, it is preferable that this characteristic is satisfied on both end faces. 0.04% or less is more preferable, and 0.03% or less is more preferable. 0% is particularly preferred. When the ratio of the number of crushed hollow fiber membranes exceeds 0.05%, blood becomes difficult to flow, blood drifts and leads to the generation of residual blood hollow fiber membranes.

  In the separation module of the present invention, the ratio of residual blood hollow fiber membranes measured by the following method is preferably 0.05% or less with respect to the total number of hollow fiber membranes per module. 0.04% or less is more preferable, and 0.03% or less is more preferable. 0% is particularly preferred. If it exceeds 0.05%, the number of residual blood hollow fiber membranes increases, which causes anxiety to dialysis patients.

  Hereinafter, the effectiveness of the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, the evaluation method of the physical property in the following examples is as follows.

1. Water content of hollow fiber membrane bundle The water content of the hollow fiber membrane bundle in the present invention was calculated by the following equation.
Moisture content (mass%) = 100 × (Ww−Wd) / Wd
Here, Ww is the hollow fiber membrane bundle (g) before drying, and Wd is the weight (g) of the hollow fiber membrane after drying for 2 hours (after absolutely dry) in a 120 ° C. dry heat oven. Here, by setting Ww within the range of 1 to 2 g, it can be in an absolutely dry state (a state in which there is no further weight change) after 2 hours.

2. Moisture content fluctuation rate of hollow fiber membrane bundle The hollow fiber membrane bundle is equally divided into 10 pieces of 2.7 cm in the longitudinal direction, and 1 g of the dry hollow fiber membrane bundle is weighed from each part. The water content was measured by the above method and calculated by the following formula.
Moisture content variation rate (%) = {(maximum moisture content value−minimum moisture content value) / average moisture content value} × 100

3. UV (220-350 nm) absorbance 100 g of pure water was added to 1 g of a hollow fiber membrane bundle, which is a method stipulated in the manufacturing standard for dialysis-type artificial kidney apparatus, and the extracted liquid was extracted at 70 ° C. for 1 hour. Absorbance in the wavelength range of 200 to 350 nm was measured using U-3000) manufactured by Seisakusho Co., Ltd., and the maximum absorbance in this wavelength range was determined.
In the measurement, the hollow fiber membrane bundle was equally divided into 10 pieces of 2.7 cm in the longitudinal direction, and 1 g of the hollow fiber membrane bundle in a dry state was weighed from each portion and measured for all samples.
In the case of the wet hollow fiber membrane module, physiological saline was passed through the dialysate side channel of the module at 500 mL / min for 5 minutes, and then passed through the blood side channel at 200 mL / min. Thereafter, the solution was passed through for 3 minutes while filtering from the blood side to the dialysate side at 200 mL / min, and then freeze-dried to obtain a dry membrane, and the above measurement was performed using the dry membrane.

4. Determination of hydrogen peroxide Hydrogen chloride solution of TiCl ₄ and 4- (2-pyridylazo) mixed in an equimolar ratio with ammonium chloride buffer (PH 8.6) 0.2 ml in 2.6 ml of the extract extracted by the above method ) Add 0.2 ml of coloring reagent prepared to 0.4 mM of a mixed solution of resorcinol with Na salt solution, heat at 50 ° C. for 5 minutes, cool to room temperature, and measure absorbance at 508 nm. It quantified with the analytical curve calculated | required similarly using the sample and calculated | required.
In the measurement, the hollow fiber membrane bundle was equally divided into 10 pieces of 2.7 cm in the longitudinal direction, and 1 g of the hollow fiber membrane bundle in a dry state was weighed from each portion and measured for all samples.
In the case of a wet hollow fiber membrane module, measurement was performed using a dry membrane obtained by processing in the same manner as the measurement of UV (220-350 nm) absorbance.

5. Partial fixing property of hollow fiber membrane bundle Using a SK cutter so that the hollow fiber membrane bundles are not fused by heat generated during cutting of the dry hollow fiber membrane bundle constrained by the package, the longitudinal direction of the hollow fiber membrane bundle Cut into 2 cm widths. While neutralizing the ring-shaped hollow fiber membrane bundle (SJ-F020, manufactured by Keyence Corporation), it was slowly dropped onto the paper surface of the desk, and it was visually confirmed whether or not a plurality of lumps were generated. In addition, when visually confirming, the thing which the lump produced by fusion | melting of the cut surface clearly was classified as not partial adhesion. If the fused state is severe, replace the blade to be cut as appropriate.

6. The length of the hollow fiber membrane In the circular cross section of the hollow fiber membrane bundle after drying, the hollow fiber membrane bundle is divided into an outer peripheral portion having a radius of 1/4 from the center point and an inner peripheral portion having a radius of 1/4 from the center point. And sampled. 500 pieces of each of the hollow fiber membranes sampled from the outer peripheral portion and the inner peripheral portion were randomly sampled, and the hollow fiber membrane lengths of all 500 pieces were measured by the following method to determine the average value. The difference between the two average lengths was determined and judged according to the following criteria. ◎ and ○ were accepted.
(Measurement method of yarn length)
Each hollow fiber membrane is sandwiched between KOKUYO W clip mouth width 15 mm and beans (Kokuyo Co., Ltd .: Cree J36), 5 mm from both ends of each hollow fiber membrane, one clip is fixed, and the other clip is free Suspend and measure the yarn length with a ruler in this state.
(Determination of shrinkage fluctuation)
A: The difference in the average value of the hollow fiber membrane length between the outer peripheral portion and the inner peripheral portion is less than 1 mm. ○: The difference in the average value of the hollow fiber membrane length between the outer peripheral portion and the inner peripheral portion is 1 mm to 3 mm or less. The difference in the average value of the hollow fiber membrane length between the outer peripheral part and the inner peripheral part exceeds 3 mm

7. Storage stability of dry hollow fiber membrane bundle and module for dry separation After the dry hollow fiber membrane bundle is stored at room temperature for 3 months in a dry box (atmosphere is air) adjusted to a humidity of 50%, the above method UV (220-350 nm) absorbance was measured. Stability was determined by the degree of increase in UV (220-350 nm) absorbance due to the storage. The degree of increase was determined by dividing the hollow fiber membrane bundle into 10 pieces of 2.7 cm in the longitudinal direction, measuring each sample, and determining the average value. Those whose average value did not exceed 0.1 were regarded as acceptable.

8. Inclined hollow fiber membrane ratio evaluation method The package of dried hollow fiber membrane bundles obtained in Examples and Comparative Examples is inserted into a module container having an inner diameter of 31 mm and a length of 255 mm, and the hollow fiber membrane is fixed while being fixed. I extracted my body. In this state, sealing jigs were attached to both ends of the container and set in a centrifugal bonding machine. While rotating the centrifugal bonding machine at a rotation speed of 500 rpm, a potting agent (two-component curable polyurethane resin manufactured by Sanyo Kasei Co., Ltd., main agent: Polymedica MA-200, curing agent: Polymedica MB, from the dialysate inlets 6a and 6b. -200, blending ratio: 52/48, viscosity after 2 minutes of mixing of two liquids: 1400 mPa · s) at 25 ° C., 20 g was injected at 0.8 g / sec per end face. The centrifugal bonding machine was stopped by curing at 50 ° C. for 30 minutes. The module was taken out and post-cured overnight at room temperature, and then 5 mm each at both ends of the module end were cut and opened to obtain a separation module. The module end face was cut to a thickness of about 0.2 mm to prepare an evaluation sample. This end face was enlarged and projected by a projector, and a hollow fiber membrane having an inclination of 15 degrees or more with respect to the normal of the end face was defined as an inclined hollow fiber membrane. The specific measurement method is as follows. That is, first, the thickness (d) of the sample was measured, and a value of d × tan 15 degrees was calculated. The sample is enlarged and projected by a projector about 20 to 50 times. If a tilted hollow fiber membrane is present, a shadow of the tilted portion occurs. The length of the shift of the shadow portion was measured. The number of hollow fiber membranes whose length is greater than the above d × tan 15 degrees is counted. A conceptual diagram is shown in FIG.
The ratio of the inclined hollow fiber membrane is calculated by the following formula.
Ratio of inclined hollow fiber membrane (%) = (number of hollow fiber membranes inclined at 15 degrees or more / total number of hollow fiber membranes on the sample end face) × 100
The following quality classification was determined by the ratio of the inclined hollow fiber membrane.
A: Ratio of inclined hollow fiber membrane is less than 0.03%
○: Ratio of inclined hollow fiber membrane 0.03 to 0.05%
X: The proportion of the inclined hollow fiber membrane exceeds 0.05%.

9. Fracture hollow fiber membrane ratio evaluation method The end face (module end face) of the sample used for the ratio evaluation of the above-mentioned inclined hollow fiber membrane is radially divided into eight parts, and the whole end face divided into eight parts is observed at a magnification of 200 times. Then, the number of crushing was counted. The standard for crushing was to measure the short diameter and long diameter of each hollow fiber membrane, and the one whose ratio was flatter than 1: 2 was defined as a crushing hollow fiber membrane. The ratio of the number of crushed hollow fiber membranes was obtained by the following formula.
Ratio of collapsed hollow fiber membranes (%) = (number of collapsed hollow fiber membranes / total number of hollow fiber membranes on the sample end face) × 100
Here, both the number of crushed hollow fiber membranes and the total number of hollow fiber membranes on the sample end surface are total counts of all the end surfaces divided into eight.
The following quality classification was determined based on the ratio of the collapsed hollow fiber membrane.
A: Less than 0.03% of hollow hollow fiber membrane
○: Ratio of collapsed hollow fiber membrane 0.03-0.05%
X: Ratio of crushing hollow fiber membrane exceeding 0.05% ◎ and ○ were regarded as acceptable.

10. Ratio of clogged hollow fiber membrane The sample end face prepared by the above method is colored with red magic ink (R), and the end face is radially marked with 8 divisions, and all 8 end faces are provided with national lights. The number of clogged hollow fiber membranes was counted using a microscope (Lightscope 100, magnification: 100 times, manufactured by Matsushita Electric Industrial Co., Ltd.). The ratio of the clogged hollow fiber membrane was calculated by the following formula.
Ratio of clogged hollow fiber membranes (%) = (number of clogged hollow fiber membranes / total number of hollow fiber membranes on the sample end face) × 100
Here, both the number of clogged hollow fiber membranes and the total number of hollow fiber membranes on the sample end surface are total counts of all end surfaces divided into eight.
The following quality classification was judged by the ratio of clogged hollow fiber membranes.
A: Ratio of clogged hollow fiber membrane is less than 0.03%
○: Ratio of clogged hollow fiber membrane 0.03-0.05%
X: The ratio of clogged hollow fiber membranes exceeding 0.05% ◎ and ○ were accepted.

11. Residual blood hollow fiber membrane ratio evaluation method The dialyzate side of the module obtained by the above method is filled with physiological saline, 200 ml of heparinized blood collected from a healthy person is packed in a blood bag, and the blood bag and the module are tubed And circulate at 37 ° C. for 1 hour at a blood flow rate of 100 ml / min. Blood samples before the start of circulation and 60 minutes of circulation are sampled, and the white blood cell count and platelet count are measured. The measured value was corrected with the value of hematocrit.
Correction value = measured value (60 minutes) x hematocrit (0 minutes) / hematocrit (60 minutes)
The change rate of leukocytes and platelets was calculated from the correction value.
Change rate = correction value (60 minutes) / value before circulation start × 100
After the circulation for 60 minutes, the blood was returned with physiological saline, and the number of remaining hollow fiber membranes was counted. The ratio of the residual blood hollow fiber membrane was calculated by the following formula.
Ratio of residual blood hollow fiber membrane (%) = (number of residual blood hollow fiber membranes / total number of hollow fiber membranes in module) × 100
The following quality classification was determined based on the percentage of residual blood hollow fiber membranes.
A: Ratio of residual blood hollow fiber membrane less than 0.03%
○: Ratio of residual blood hollow fiber membrane 0.03-0.05%
X: Ratio of residual blood hollow fiber membrane exceeding 0.05% ◎ and ○ were accepted.

12. Water permeability The blood outlet circuit (outlet side from the pressure measurement point) of the dialyzer was sealed with forceps. Purified water kept at 37 ° C is put into a pressurized tank, and the pressure is controlled by a regulator, while pure water is sent to the blood flow path side of the dialyzer kept at 37 ° C constant temperature bath, and the amount of filtrate that flows out from the dialysate side Was measured. The transmembrane pressure difference (TMP) is TMP = (Pi + Po) / 2
And Here, Pi is the dialyzer inlet side pressure, and Po is the dialyzer outlet side pressure. The TMP is changed at four points, the filtration flow rate is measured, and the water permeability (mL / hr / mmHg) is calculated from the slope of the relationship. At this time, the correlation coefficient between TMP and the filtration flow rate must be 0.999 or more. In order to reduce the pressure loss error due to the circuit, TMP is measured in the range of 100 mmHg or less. The water permeability of the hollow fiber membrane bundle is calculated from the membrane area and the water permeability of the dialyzer.
UFR (H) = UFR (D) / A
Here, UFR (H) is the water permeability of the hollow fiber membrane bundle (mL / m ² / hr / mmHg), UFR (D) is the water permeability of the dialyzer (mL / hr / mmHg), and A is the membrane area of the dialyzer. (M ² ).

13. Calculation of membrane area The membrane area of the dialyzer is determined as a reference for the inner diameter of the hollow fiber membrane.
A = n × π × d × L
Here, n is the number of hollow fibers in the dialyzer, π is the circumference ratio, d is the inner diameter (m) of the hollow fiber membrane, and L is the effective length (m) of the hollow fibers in the dialyzer.

14. Blood Leak Test A 37 ° C. bovine blood to which citrate is added and coagulation is suppressed is fed to the separation module at 200 mL / min, and the blood is filtered at a rate of 10 mL / min (m ² ). At this time, the filtrate is returned to blood to be a circulatory system. After 60 minutes, the filtrate of the separation module is collected, and the red color caused by red blood cell leakage is visually observed. In this blood leak test, 30 separation modules were used in each example and comparative example, and the number of blood leaked modules was examined.

15. Storage stability of wet hollow fiber membrane bundle and module for wet separation Inclined hollow fiber membrane ratio evaluation method Module prepared by the same method is filled with degassed RO water and irradiated with γ-rays with an absorbed dose of 25 kGy Crosslinking treatment was performed. After storing the module after γ-ray irradiation for one year at room temperature, UV (220-350 nm) absorbance was measured by the method described above. Stability was determined by the degree of increase in UV (220-350 nm) absorbance due to the storage. The degree of increase was obtained by equally dividing the hollow fiber membrane bundle into 10 pieces in the longitudinal direction, measuring each sample, and determining the average value. Those whose average value did not exceed 0.10, which is the reference value of the dialysis artificial kidney device manufacturing standard, were regarded as acceptable.

Example 1
Polyethersulfone (Sumika Chemtex Co., Ltd., Sumika Excel (R) 5200P) 17.3 mass%, Polyvinylpyrrolidone (BASF Kollidon (R) K-90) 2.5 mass%, DMAc 26.0 mass% 2 It knead | mixed with the screw type kneading machine of the axis | shaft. The obtained kneaded product was added to a stirring type dissolver charged with 51.3% by mass of DMAc and 2.9% by mass of water, and dissolved by stirring for 3 hours. The kneading and dissolution were cooled so that the internal temperature did not rise above 30 ° C. The system was then depressurized to -500 mmHg using a vacuum pump, and the system was immediately sealed and allowed to stand for 15 minutes so that the solvent etc. evaporated and the film forming solution composition did not change. This operation was repeated three times to degas the film forming solution. After the defoaming was completed, the inside of the system was again purged with nitrogen and maintained in a weakly pressurized state. As the polyvinyl pyrrolidone, one having a hydrogen peroxide content of 110 ppm was used, and the supply tank in the raw material supply system and the dissolution tank were replaced with nitrogen gas. Further, the Froude number and the stirring Reynolds number at the time of dissolution were 1.1 and 120, respectively. The membrane-forming solution was passed through a two-stage sintered filter of 10 μm and 5 μm in order, and then degassed at −700 mmHg for 30 minutes in advance from a tube-in orifice nozzle heated to 75 ° C. for 60 mass at 50 ° C. After passing through a 400 mm dry section, which was discharged with a% DMAc aqueous solution and cut off from the outside air by a spinning tube, it was coagulated in a 20 wt% DMAc aqueous solution at 60 ° C., and was rolled up in a wet state. The nozzle slit width of the tube-in-orifice nozzle used was an average of 60 μm, the maximum 61 μm, the minimum 59 μm, the ratio of the maximum and minimum slit widths was 1.03, and the draft ratio was 1.2.

  A film made of polyethylene having a thickness of 0.2 mm and having a satin-finished surface of the hollow fiber bundle side of the 10,000 hollow fiber membranes (dielectric constant: 2.3, dielectric loss tangent: 0.0002, product of dielectric constant and dielectric loss tangent: 0.00046) was inserted into a hollow package (outer diameter 36 mm) having a circular cross-sectional shape, cut to a length of 270 mm, and washed in hot water at 80 ° C. for 30 minutes × 4 times. A package body in which the washed hollow fiber membrane bundle is constrained is provided with a semicircular recess in the upper surface of the tray in accordance with the shape of the package body. Dielectric constant: 3.5, dielectric loss tangent: 0.0035, dielectric constant and dielectric loss tangent The product is put into a hollow portion of a tray made of polyethersulfone of 0.01225, and centrifuged and dehydrated at 140 rpm for 20 minutes with a centrifugal dehydrator to obtain a dehydrated hollow fiber membrane bundle having a water content of 300% by mass. Obtained. The resulting dehydrated hollow fiber membrane bundle is installed with a tray and a microwave oscillator on the side wall of the heating oven, the microwave can oscillate in the horizontal direction, has a horizontal rotating table inside the oven, and has a far infrared heater and oven. Six hollow fiber membrane bundles are arranged at equal intervals in the direction in which the longitudinal direction of the hollow fiber membrane bundle is horizontal on the rotary table of a microwave dryer having an exhaust system for reducing the pressure. Arranged to face the center. The rotary table has a structure in which a 6 mm thick polypropylene plate is fixed on a metal holding jig, and the upper surface of the table is located about 30 mm below the center of the waveguide of the microwave oscillator. Has been. The rotary table was dried under the following conditions while rotating at 8 rpm. After heating the hollow fiber membrane bundle for 25 minutes under a reduced pressure of 7 kPa and an output of 1.5 kW, the microwave irradiation was stopped and simultaneously the pressure was increased to 1.5 kPa and maintained for 3 minutes. Subsequently, the degree of vacuum was returned to 7 kPa, the microwave was irradiated and the hollow fiber membrane bundle was heated at an output of 0.5 kW for 8 minutes, and then the microwave was cut to increase the degree of vacuum and maintain 0.7 kPa for 3 minutes. Furthermore, the degree of vacuum was returned to 7 kPa, and microwave irradiation was performed for 5 minutes at an output of 0.2 kW to heat the hollow fiber membrane bundle. The water content in the hollow fiber membrane bundle after the microwave irradiation was 11% by mass. After microwave cutting, the degree of vacuum was increased to 0.5 kPa, irradiation with far infrared rays alone was performed, and the drying of the hollow fiber membrane bundle was completed by maintaining for 10 minutes. During drying, the output of the far-infrared heater was adjusted so that the temperature detected by a thermocouple provided at the center of the drying oven was 50 ° C. over the entire period. The maximum temperature reached on the surface of the hollow fiber membrane bundle at this time was 65 ° C. Note that the waveguide of the microwave oscillator of the above microwave dryer has a cross-sectional area that gradually increases in the direction of microwave travel, and a conical reflector at the exit of the waveguide. It had the structure installed in the direction facing the inside, and Er / Ei of the irradiated microwave was 0.05. Further, the moisture content after the final drying was 2.5% by mass. The obtained hollow fiber membrane bundle had an inner diameter of 198 μm and a film thickness of 28 μm. The filling rate of the dry hollow fiber membrane bundle in the package was 50%. During the spinning process, all the rollers with which the hollow fiber membrane bundle contacts were mirror-finished on the surface, and the guides were all finished with a satin finish.

  The drying process processed 6 samples simultaneously. The difference of the average value of the hollow fiber membrane length of an outer peripheral part and an inner peripheral part was calculated | required by 1 sample of the obtained dry hollow fiber membrane bundle. The shrinkage variation of the hollow fiber membrane was small and was 0.5 mm or less. Moreover, the hollow fiber membrane sample of the outer peripheral part of the hollow fiber membrane bundle (with a radius of 1/4) was sampled with another sample, and the sample was equally divided into 10 pieces of 2.7 cm in the longitudinal direction. Each 1 g of the dried hollow fiber membrane was weighed and the moisture content was measured. Moreover, the extract was obtained according to the dialysis type artificial kidney apparatus manufacture approval reference test, and the hydrogen peroxide concentration and UV (220-350 nm) absorbance in the extract were measured. The variation of moisture content was small. Moreover, hydrogen peroxide and UV (220-350 nm) absorbance were stable at a low level in all sites. Further, the dried hollow fiber membrane bundle length was assumed to be 265 mm, and the wet hollow fiber membrane bundle length was set to 270 mm and dried. These results are summarized in Tables 1-3. Further, one sample of the obtained hollow fiber membrane bundle was stored in a dry state, and the storage stability was evaluated. The storage stability in the dry state is good, and the average value of UV (220-350 nm) absorbance of the extract obtained from each part obtained by dividing the hollow fiber membrane bundle after storage for 3 months into 10 equal parts is 0.024. Yes, even when viewed at the maximum value, the reference value of less than 0.10 was maintained. Furthermore, the UV absorbance level at each site was stable at a low level.

  The remaining three samples of the dry hollow fiber membrane bundle constrained by the polyethylene film obtained by the above method are inserted into a module container having an inner diameter of 31 mm and a length of 255 mm, and made of a polyethylene film while fixing the hollow fiber membrane. The package was removed. In this state, sealing jigs were attached to both ends of the container and set in a centrifugal bonding machine. While rotating the centrifugal bonding machine at a rotation speed of 500 rpm, a potting agent (two-component curable polyurethane resin manufactured by Sanyo Kasei Co., Ltd., main agent: Polymedica MA-200, curing agent: Polymedica MB, from the dialysate inlets 6a and 6b. -200, blending ratio: 52/48, viscosity after 2 minutes mixing: 1400 mPa · s) was injected at 25 ° C. at 20 g at 0.8 g / sec per end face. The centrifugal bonding machine was stopped by curing at 50 ° C. for 30 minutes. The module was removed and post-cured overnight at room temperature. The end face was cut and opened to obtain a hollow fiber membrane module. The module was filled with RO water that had been removed beforehand, and γ-rays were irradiated at an absorbed dose of 25 kGy for crosslinking treatment. The dried hollow fiber membrane bundle obtained in this example is not deformed such as bending of the hollow fiber membrane bundle in the drying step, there is little disorder in the arrangement of the hollow fiber membranes in the hollow fiber membrane bundle, and partial sticking is also possible. Since it did not occur, the package could be removed smoothly. Also, the workability of the adhesion treatment was good. The number of inclined hollow fiber membranes and crushed hollow fiber membranes by cross-sectional observation of the bonded end face was zero. Moreover, the clogged hollow fiber membrane evaluated by the above method was not detected. Therefore, there was no residual blood hollow fiber membrane and the quality was high.

The citrated fresh bovine blood was passed through the separation module at a blood flow rate of 200 mL / min and a filtration rate of 10 mL / min (m ² ). However, poor adhesion and blood leakage due to partial adhesion of the hollow fiber membranes. Was not seen. These results are shown in Table 4.

  The wet separation module was stored at room temperature for 1 year. When the hollow fiber membrane bundle was cut out from the separation module after storage and subjected to the eluate test, the UV (220-350 nm) absorbance was 0.04 in terms of the maximum value. Some less than 0.10 was maintained.

  Also in the following examples and comparative examples, 6 samples were simultaneously dried in the same manner as in this example and subjected to various evaluations.

(Comparative Example 1)
In Example 1, the packaging body and the tray material that restrain the wet hollow fiber membrane bundle are polycarbonate resin having a dielectric constant of 2.9, a dielectric loss tangent of 0.009, and a product of dielectric constant and dielectric loss tangent of 0.0261. A hollow fiber membrane bundle of Comparative Example 1 was obtained in the same manner as in Example 1 except that the above was changed. In the case of this comparative example, since the package and the tray are made of polycarbonate resin having low microwave drying permeability, the package and the tray generate a large amount of heat generated by the microwaves, and the hollow fiber membrane bundle outer peripheral portion and inner peripheral portion The temperature difference between the hollow fiber membranes of each of the hollow fiber membranes increases, and this causes a difference in shrinkage rate, and the shrinkage of the hollow fiber membranes on the outer peripheral portion, which is greatly affected by the heat generation, is larger than that on the inner peripheral portion. The difference in film length was 4 mm.

  In addition, Tables 1 to 3 show the water content, the hydrogen peroxide concentration, and the UV absorbance measured values of the dry hollow fiber membrane bundle obtained in this Comparative Example. Here, the hydrogen peroxide concentration and the UV absorbance measurement values are evaluated for the hollow fiber membranes in the outer peripheral portion (in the range of ¼ radius) of the hollow fiber membrane bundle. In the method of this comparative example, deterioration of polyvinyl pyrrolidone, which is a component of the hollow fiber membrane, increases due to the temperature rise of the outer peripheral portion of the hollow fiber membrane bundle, and the drying uniformity in the longitudinal direction of the hollow fiber membrane bundle decreases. Therefore, the hydrogen peroxide elution amount of the hollow fiber membrane bundle obtained in this comparative example was high, and the fluctuation of the hydrogen peroxide elution amount depending on the sampling location was large and the quality was low. Furthermore, since the hollow fiber membrane bundle of this comparative example had a high hydrogen peroxide elution amount, the storage stability was inferior. The hollow fiber membrane bundle in a dry state obtained in this comparative example had an average value of UV (220-350 nm) absorbance exceeding 0.10 after storage for about 30 days. In addition, the UV (220-350 nm) absorbance of the dried hollow fiber membrane bundle varied greatly depending on the sampling site, partial sticking occurred, and the module assembly workability was poor.

  Further, the separation module was assembled by the same method as in Example 1, but the arrangement of the hollow fiber membranes in the hollow fiber membrane bundle was disturbed, and the package could not be removed smoothly. Therefore, it takes time and effort to align the end faces of the hollow fiber membrane bundle loaded after the package is pulled out, and the filling property of the adhesive is poor and the workability is inferior due to the disordered arrangement of the hollow fiber membrane bundle. Moreover, since the shrinkage spots of the hollow fiber membrane were large as described above, a large number of clogged hollow fiber membranes were detected. For this reason, a residual blood hollow fiber membrane was generated and the quality was low. Further, the hollow fiber membrane bundle of this comparative example has a high hydrogen peroxide elution amount level of the hollow fiber membrane bundle and poor storage stability of the separation module, and the average value of UV (220-350 nm) absorbance is about 2 months for dialysis. The value of 0.10, which is the standard value for manufacturing type artificial kidney device, has been exceeded. The results are shown in Table 4.

(Comparative Example 2)
In Example 1, the hollow fiber membrane bundle to be dried was changed so as to be arranged vertically, and microwave drying was performed for 40 minutes at an output of 2.0 kW at normal pressure, and then for 10 minutes at an output of 0.9 kW. Thus, a hollow fiber membrane bundle was obtained by the same method as in Example 1 except that irradiation with far-infrared radiation was changed to dry for 20 minutes under normal pressure. In this comparative example, since the hollow fiber membrane bundles to be dried were arranged vertically, the obtained dry hollow fiber membrane bundles were bent due to buckling that occurred during drying. Using one sample of the obtained dry hollow fiber membrane bundle, the yarn length of all hollow fiber membranes of the hollow fiber membrane bundle was measured. There were many hollow fiber membranes of 264 mm or less and hollow fiber membranes of 268 mm or more.

  In addition, Tables 1 to 3 show the water content, the hydrogen peroxide concentration, and the UV absorbance measured values of the dry hollow fiber membrane bundle obtained in this Comparative Example. Here, the hydrogen peroxide concentration and the UV absorbance measurement values are evaluated for the hollow fiber membranes in the outer peripheral portion (in the range of ¼ radius) of the hollow fiber membrane bundle. In the method of this comparative example, the degradation of polyvinyl pyrrolidone, which is a component of the hollow fiber membrane, is large and the uniformity of drying in the longitudinal direction of the hollow fiber membrane bundle is inferior. Therefore, the hollow fiber membrane bundle obtained in this comparative example The amount of hydrogen peroxide eluted was high, and the amount of hydrogen peroxide eluted greatly varied depending on the sampling location. Furthermore, since the hollow fiber membrane bundle of this comparative example had a high hydrogen peroxide elution amount, the storage stability was inferior. The hollow fiber membrane bundle in a dry state obtained in this comparative example had an average value of UV (220-350 nm) absorbance exceeding 0.10 after storage for about 30 days. In addition, the UV (220-350 nm) absorbance of the dried hollow fiber membrane bundle varied greatly depending on the sampling site, partial sticking occurred, and the module assembly workability was poor.

  Further, the separation module was assembled by the same method as in Example 1, but the arrangement of the hollow fiber membranes in the hollow fiber membrane bundle was disturbed, and the package could not be removed smoothly. Therefore, it takes time and effort to align the end faces of the hollow fiber membrane bundle loaded after the package is pulled out, and the filling property of the adhesive is poor and the workability is inferior due to the disordered arrangement of the hollow fiber membrane bundle. In addition, a large number of inclined hollow fiber membranes, collapsed hollow fiber membranes and clogged hollow fiber membranes were detected. For this reason, many residual blood hollow fiber membranes were generated and the quality was low. Furthermore, the hollow fiber membrane bundle of this comparative example has a high hydrogen peroxide elution amount level of the hollow fiber membrane bundle and poor storage stability of the separation module, and the average value of UV (220-350 nm) absorbance is about 2.5 months. As a result, the dialysis artificial kidney device manufacturing approval standard value of 0.10 was exceeded. The results are shown in Table 4.

(Comparative Example 3)
In the method of Comparative Example 1, the waveguide of the microwave oscillator of the microwave dryer has a structure in which the cross-sectional area is constant facing the traveling direction of the microwave, and the reflector at the waveguide outlet is not installed. The microwave Er / Ei of the irradiated microwave was changed to a microwave oscillator having a value of 0.3, and the hollow fiber membrane bundle was dried for 40 minutes at a normal pressure with an output of 2.0 kW at a normal pressure. A hollow fiber membrane bundle was obtained in the same manner as in Comparative Example 1 except that irradiation was carried out for 10 minutes at an output of .9 kW, and far-infrared irradiation was changed to dry for 20 minutes under normal pressure. The characteristics of the obtained hollow fiber membrane bundle are shown in Tables 1-3. In the hollow fiber membrane bundle obtained in this comparative example, deformation of the hollow fiber membrane in the drying process occurred in the same manner as the hollow fiber membrane bundle obtained in comparative example 1, and the structure of the microwave drying oscillator and the drying Since the non-uniformity of drying of the hollow fiber membrane bundle was increased by changing the conditions, the quality was inferior to that of the hollow fiber membrane bundle obtained in Comparative Example 1. For example, the dried hollow fiber membrane bundle obtained in this comparative example was stored for 25 days, and the UV (220-350 nm) absorbance of the extract prepared according to the test method of the dialysis artificial kidney device manufacturing approval standard The average value of exceeded the reference value of 0.10. Further, the UV (220-350 nm) absorbance of the dried hollow fiber membrane bundle varies greatly depending on the sampling site, partial sticking occurs, and the module assembly workability is higher than that of the hollow fiber membrane bundle obtained in Comparative Example 1. It was inferior.
Further, the separation module was assembled by the same method as in Example 1, but the arrangement of the hollow fiber membranes in the hollow fiber membrane bundle was disturbed similarly to the hollow fiber membrane bundle obtained in Comparative Example 1, and the package. It was not possible to pull out smoothly. Therefore, it takes time and effort to align the end faces of the hollow fiber membrane bundle loaded after the package is pulled out, and the filling property of the adhesive is poor and the workability is inferior due to the disordered arrangement of the hollow fiber membrane bundle. Further, as a result of observation of the adhesion end face, a large number of inclined hollow fiber membranes, collapsed hollow fiber membranes, and clogged hollow fiber membranes were detected. Therefore, many residual blood hollow fiber membranes were observed and the quality was low. The results are shown in Table 4.

(Example 2)
In the same manner as in Example 1, polyethersulfone (Sumika Chemtex, Sumika Excel (R) 4800P) 18% by mass, polyvinylpyrrolidone (BASF Kollidon (R) K-90) 3.8% by mass, dimethyl A film forming solution consisting of 73.2% by mass of acetamide (DMAc) and 5% by mass of water was obtained. As the polyvinyl pyrrolidone, one having a hydrogen peroxide content of 90 ppm was used. The obtained film-forming solution was passed through a two-stage filter of 15 μm and 15 μm, and then degassed at −700 mmHg for 2 hours in advance from a tube-in orifice nozzle heated to 70 ° C. for 50 mass at 60 ° C. The solution was discharged at the same time as the% DMAc aqueous solution, passed through a 350 mm air gap portion cut off from the outside air by a spinning tube, and then coagulated in water at 60 ° C. The average nozzle slit width of the tube-in-orifice nozzle used was 45 μm, the maximum was 45.5 μm, the minimum was 44.5 μm, the ratio of the maximum and minimum slit widths was 1.02, and the draft ratio was 1.3. It was. The hollow fiber membrane bundle pulled up from the coagulation bath was passed through a water washing tank at 85 ° C. for 45 seconds to remove the solvent and excess polyvinylpyrrolidone, and then wound up.

  A polypropylene film having a thickness of 0.2 mm, with 10,080 hollow fiber membranes having a textured surface on the hollow fiber bundle side (dielectric constant: 2.2, dielectric loss tangent: 0.0002, product of dielectric constant and dielectric loss tangent: 0.00044) is inserted into a package made of a hollow package (outer diameter: 36 mm) having a circular cross-section, and then immersed and washed in a 40 vol% isopropanol aqueous solution at 30 ° C. for 30 minutes × 2 times. The ratio is 3.3, the dielectric loss tangent is 0.003, and the product of the dielectric constant and the dielectric loss tangent is 0.0099. The hollow fiber membrane bundle having a water content of 3.0% by mass was obtained by drying according to the drying method No. 1. The roller for changing the yarn path during the spinning process was a mirror-finished surface, and the fixing guide was a satin-finished surface. The resulting hollow fiber membrane had an inner diameter of 199 μm and a film thickness of 27 μm.

The hollow fiber membrane bundle obtained in this example was of high quality like the hollow fiber membrane bundle of Example 1. The results are shown in Tables 1-3.
Moreover, the module for separation was obtained by the same method as Example 1 using the obtained dry hollow fiber membrane bundle. The obtained separation module was of high quality as was the separation module obtained in Example 1. The results are shown in Table 4.

(Example 3)
In the same manner as in Example 1, 18% by mass of polysulfone (P-3500 manufactured by Amoco), 9% by mass of polyvinylpyrrolidone (Collidon (R) K-60 manufactured by BASF), 68% by mass of dimethylacetamide (DMAc), water A film forming solution consisting of 5% by mass was obtained. In addition, as said polyvinylpyrrolidone, the hydrogen peroxide content rate 100ppm was used. The obtained film-forming solution was passed through two types of filters of 15 μm and 15 μm, and simultaneously with a 35 mass% DMAc aqueous solution at 60 ° C. which was degassed in advance as a hollow forming agent from a tube-in orifice nozzle heated to 40 ° C. After discharging and passing through a 600 mm air gap portion cut off from the outside air by a spinning tube, it was solidified in 50 ° C. water. The nozzle slit width of the tube-in-orifice nozzle used was an average of 60 μm, the maximum 61 μm, the minimum 59 μm, the ratio of the maximum and minimum slit widths was 1.03, and the draft ratio was 1.1. The hollow fiber membrane bundle pulled up from the coagulation bath was passed through a water washing tank at 85 ° C. for 45 seconds to remove the solvent and excess polyvinylpyrrolidone, and then wound up. A bundle of about 10,000 hollow fiber membranes was immersed in pure water and washed in an autoclave at 121 ° C. for 1 hour. The washed hollow fiber membrane bundle is inserted into a package made of the same polyethylene film as in Example 1, and the material of the tray is the dielectric constant: 3.1, the dielectric loss tangent: 0.005, and the product of the dielectric constant and the dielectric loss tangent. : Except for changing to a polysulfone resin of 0.01550, after fixing to the same tray as used in Example 1, this was dried by a method according to the drying method of Example 1, and the water content was 2.0 mass % Dry hollow fiber membrane bundle was obtained. The roller for changing the yarn path during the spinning process was a mirror-finished surface, and the fixing guide was a satin-finished surface. The obtained hollow fiber membrane bundle had an inner diameter of 201 μm and a film thickness of 44 μm.

The hollow fiber membrane bundle obtained in this example was of high quality like the hollow fiber membrane bundle of Example 1. The results are shown in Tables 1-3.
Moreover, the module for separation was obtained by the same method as Example 1 using the obtained dry hollow fiber membrane bundle. The obtained separation module was of high quality as was the separation module obtained in Example 1. The results are shown in Table 4.

Example 4
In the same manner as in Example 1, 17% by mass of polysulfone (Amoco P-1700), 5% by mass of polyvinylpyrrolidone (BASF Kollidon (R) K-60), 73% by mass of dimethylacetamide (DMAc), water A film forming solution consisting of 5% by mass was obtained. The polyvinyl pyrrolidone used was a hydrogen peroxide content of 120 ppm. The obtained film-forming solution was passed through two types of filters of 15 μm and 15 μm, and simultaneously with a 35 mass% DMAc aqueous solution at 65 ° C. degassed as a hollow forming agent from a tube-in orifice nozzle heated to 40 ° C. After discharging and passing through a 600 mm air gap portion cut off from the outside air by a spinning tube, it was solidified in 50 ° C. water. The nozzle slit width of the tube-in-orifice nozzle used was an average of 60 μm, the maximum 61 μm, the minimum 59 μm, the ratio of the maximum and minimum slit widths was 1.03, and the draft ratio was 1.2. The hollow fiber membrane bundle pulled up from the coagulation bath was passed through a water washing tank at 85 ° C. for 45 seconds to remove the solvent and excess polyvinylpyrrolidone, and then wound up. A bundle of about 10,000 hollow fiber membranes was immersed in pure water and washed in an autoclave at 121 ° C. for 1 hour. The roller for changing the yarn path during the spinning process was a mirror-finished surface, and the fixing guide was a satin-finished surface.

  The packaging and tray material for restraining the hollow fiber membrane bundle after washing was changed to polyethylene terephthalate resin having a dielectric constant of 3.2, a dielectric loss tangent of 0.0021, and a product of the dielectric constant and the dielectric loss tangent of 0.00672. According to Example 1, it was dried so that the water content was 1.5% by mass. The resulting hollow fiber membrane had an inner diameter of 201 μm and a film thickness of 43 μm.

The hollow fiber membrane bundle obtained in this example was of high quality like the hollow fiber membrane bundle of Example 1. The results are shown in Tables 1-3.
Moreover, the module for separation was obtained by the same method as Example 1 using the obtained dry hollow fiber membrane bundle. The obtained separation module was of high quality as was the separation module obtained in Example 1. The results are shown in Table 4.

(Comparative Example 4)
In the method of Example 4, the material of the package that restrains the wet hollow fiber membrane bundle is a polycarbonate resin having a dielectric constant of 2.9, a dielectric loss tangent of 0.009, and a product of dielectric constant and dielectric loss tangent of 0.0261. A hollow fiber membrane bundle was obtained in the same manner as in Example 4 except that the drying of the hollow fiber membrane bundle was changed as follows. Dehumidified air (humidity of 10% or less) from the lower part of the hollow fiber membrane bundle at a wind speed of 8 m / sec. Irradiated to obtain a hollow fiber membrane bundle having a water content of 18% by mass. The hollow fiber membrane bundle was transferred to a hot air drier and dried under normal pressure at a temperature of 87 ° C. for 1.5 hours to obtain a dry hollow fiber membrane bundle having a water content of 0.7 mass%.

The characteristics of the obtained hollow fiber membrane bundle are shown in Tables 1-3. Using one sample of the obtained dry hollow fiber membrane bundle, the yarn length of all hollow fiber membranes of the hollow fiber membrane bundle was measured. There were many hollow fiber membranes of 264 mm or less and hollow fiber membranes of 268 mm or more. Moreover, the fluctuation | variation of the moisture content of the hollow fiber membrane bundle obtained by this comparative example was high. Furthermore, the hydrogen peroxide elution amount was high, and the amount of hydrogen peroxide elution amount varied greatly depending on the sampling location, resulting in low quality. Furthermore, since the hollow fiber membrane bundle of this comparative example had a high hydrogen peroxide elution amount, the storage stability was inferior. The hollow fiber membrane bundle in the dry state obtained in this comparative example was stored for about 20 days, and the average value of UV (220-350 nm) absorbance exceeded the standard value of 0.10. In addition, the UV (220-350 nm) absorbance of the dried hollow fiber membrane bundle varied greatly depending on the sampling site, partial sticking occurred, and the module assembly workability was poor.
Further, a separation module was obtained by the same method as in Example 1 using the dry hollow fiber membrane bundle obtained in this Comparative Example. The obtained separation module was also of low quality like the separation modules obtained in Comparative Examples 1 and 2. The results are shown in Table 4.

(Comparative Example 5)
In Example 1, the packaging material and the tray material that restrain the wet hollow fiber membrane bundle are made into a vinyl chloride resin having a dielectric constant of 3, a dielectric loss tangent of 0.01, and a product of dielectric constant and dielectric loss tangent of 0.030. A hollow fiber membrane bundle of Comparative Example 1 was obtained in the same manner as in Example 1 except for changing. The hollow fiber membrane bundle and separation module obtained in this comparative example were of low quality, similar to the hollow fiber membrane bundle and separation module obtained in comparative example 1.

The separation module obtained by the method of the present invention is a defective hollow fiber such as a hollow fiber membrane, a crushed hollow fiber membrane and a clogged hollow fiber membrane in which the inclination of the hollow fiber membrane in the portion fixed with resin is 15 degrees or more. The ratio of the membrane is suppressed, and it has the advantage that it is excellent in residual blood property and excellent in long-term storage stability and can be suitably used for blood purification.
In addition, the hollow fiber membrane bundle dried by the method of the present invention improves, for example, the insertion property of the hollow fiber membrane bundle into the module container in the separation module assembling process and the bonding work when the module is assembled in the next process. To do. Furthermore, the occurrence of defective hollow fiber membranes such as tilted hollow fiber membranes, crushed hollow fiber membranes and clogged hollow fiber membranes due to deformation and shrinkage spots is suppressed, and residual blood properties caused by these defects are improved. There is an advantage. In addition, since the hollow fiber membrane is prevented from being broken or damaged, blood leakage is improved. Further, in the present invention, the wet hollow fiber membrane bundle is restrained by the hollow package, so that the workability of placing the hollow fiber membrane bundle to be dried in the dryer is improved and the dried hollow fiber membrane bundle is It is restrained by a hollow packaging body as a unit of number to be loaded into a module to be assembled using a yarn membrane bundle, and the dried hollow fiber membrane bundle is loaded into a module container as it is, and then the hollow body is pulled out by removing the packaging body. The membrane bundle can be loaded into the module container, so that the workability of the loading can be greatly improved, and there is an advantage that the generation of the defective hollow fiber membrane at the time of loading is suppressed. Therefore, it is important to contribute to the industry.

It is a schematic diagram which shows the correlation with the drying time and moisture content of a hollow fiber membrane bundle. It is a schematic diagram which shows the relationship between a dry switching moisture content and the variation degree of quality. It is sectional drawing of the module for hollow fiber type | mold isolation | separation. It is an enlarged view of a module edge part (adhesive resin part). It is a conceptual diagram of the ratio evaluation method of an inclination hollow fiber membrane. It is a schematic diagram showing distribution of an inclination hollow fiber membrane. It is a schematic diagram showing the relationship between an inclination hollow fiber membrane and the amount of residual blood.

Explanation of symbols

1: Separation module 2: Container 3: Hollow fiber membrane bundle 4: Adhesive resin 5: Cap 6a: Dialysate inlet 6b: Dialysate outlet 7a: Blood inlet 7b: Blood outlet 11: Adhesive resin 12: Hollow Yarn membrane

Claims (6)

  In a separation module in which both ends of a hollow fiber membrane bundle made of a polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin, the proportion of the hollow fiber membrane in which the inclination of the hollow fiber membrane in the portion fixed with the resin is 15 degrees or more is After the module is sterilized at 0.05% or less and stored in a wet state at room temperature for 1 year, the hollow fiber membrane bundle is divided into 10 pieces in the longitudinal direction, and each is manufactured as a dialysis artificial kidney device A separation module, characterized in that the UV (220 to 350 nm) absorbance in the hollow fiber membrane extract when the test defined by the approval criteria is carried out is 0.10 or less on average.   In a separation module in which both ends of a hollow fiber membrane bundle made of a polysulfone-based resin containing polyvinylpyrrolidone are fixed with a resin, the proportion of the hollow fiber membrane in which the inclination of the hollow fiber membrane in the portion fixed with the resin is 15 degrees or more is After sterilizing the module at 0.05% or less and storing it in a dry state at room temperature for 3 months, the hollow fiber membrane bundle is divided into 10 pieces in the longitudinal direction, and each is a dialysis artificial kidney device A separation module, characterized in that UV (220 to 350 nm) absorbance in an extract of a hollow fiber membrane when a test defined by a manufacturing approval standard is carried out is 0.10 or less on average.   The separation module according to claim 1 or 2, wherein the ratio of the crushed hollow fiber membrane is 0.05% or less.   The separation module according to any one of claims 1 to 3, wherein the ratio of the clogged hollow fiber membrane is 0.05% or less.   The separation module according to any one of claims 1 to 4, wherein the ratio of the residual blood hollow fiber membrane is 0.05% or less with respect to the total number of hollow fiber membranes per module. The separation module according to claim 1, wherein the separation module is used for blood purification.