JP5423326B2 - Method for producing hollow fiber membrane - Google Patents

Description

  The present invention relates to a polymer porous hollow fiber membrane used for liquid treatment in the food field, pharmaceutical field, semiconductor field, energy field and water treatment field. Specifically, the present invention relates to a method for producing a hollow fiber membrane having high filtration performance of wine yeast liquor and high pressure resistance.

  Hollow fiber membranes used for liquid processing in the food, pharmaceutical, semiconductor, energy and water treatment fields are used for industrial applications such as microfiltration and ultrafiltration, as well as hemodialysis, blood filtration, hemodiafiltration, etc. Widely used in medical applications.

  In particular, diatomaceous earth has been used to remove fermented wine, yeast in beer, solids, colloids, etc., in the treatment of fermentation broth in the food field. No diatomaceous earth can be incinerated, and since it is used in large quantities, there is a problem of high cost for disposal. Therefore, in recent years, attention has been paid to the treatment of fermentation broth with a hollow fiber-shaped ultrafiltration membrane or a microfiltration membrane that is excellent in miniaturization of the apparatus.

  When processing fermented liquor such as wine and beer with a hollow fiber membrane module, it is generally performed by applying a high pressure of about 1 to 1.5 bar while flowing the fermented liquid through the hollow part of the hollow fiber membrane at a high flow rate. The fermentation liquor is purified by filtering from the inner surface side to the outer surface side of the hollow fiber membrane by cross flow filtration. In this case, a hollow fiber membrane having a high pressure resistance per unit membrane area of the hollow fiber membrane, a low clogging of the end surface of the hollow fiber, and a high pressure resistance is required.

  In order to increase the filtration performance, it is necessary to lower the polymer concentration of the spinning dope and increase the solvent concentration of the core solution. On the other hand, in order to reduce the clogging of the hollow fiber end face, it is necessary to increase the inner diameter sufficiently, but if the film thickness is not increased sufficiently, the pressure resistance will be weak and the film will be damaged during use. Can not be.

  However, under the conditions where the polymer concentration is lowered and the solvent concentration of the core solution is increased, the inner diameter is sufficiently large so as not to cause clogging of the end surface of the hollow fiber membrane, and the film thickness is sufficiently large so that the membrane is not damaged during use. If it is increased, the hollow fiber membrane that has been immersed in the coagulation bath from the double tube cap through the air running part will loosen in the coagulation bath and cannot be spun, and the inner diameter and film thickness cannot be increased sufficiently. there were.

  As a method of changing the progress of the hollow fiber membrane with a slack prevention guide in the coagulation bath, the distance between the submerged roller and the take-up roller of the coagulation bath is set to 1.01 to 1.5 times the length of the shortest distance. There is a method for improving the roundness of the yarn membrane (see Patent Document 1). However, in this method, when the discharge amount of the spinning solution is increased, the hollow fiber membrane is loosened in the coagulation bath and spinning cannot be performed.

  Also, when changing the traveling direction of the hollow fiber membrane by the slack prevention guide in the coagulation bath in dry and wet spinning using gas as the hollow forming material, the traveling direction of the hollow fiber membrane is changed by the plurality of slack prevention guides. There is a method for improving the roundness of a hollow fiber membrane (see Patent Document 2). However, even in this method, if the discharge amount of the spinning solution is increased, the hollow fiber membrane is loosened in the coagulation bath and spinning becomes impossible.

  When manufacturing multiple hollow fiber membranes at the same time, install an in-liquid direction change guide and separate the multiple hollow fiber membranes for each yarn between the coagulation bath liquid level and the slack prevention guide. There is a method of preventing yarn fusing and eliminating yarn breakage due to fusing (Patent Document 3). However, even in this method, if the discharge amount of the spinning solution is increased, the hollow fiber membrane is loosened in the coagulation bath and spinning cannot be performed.

  In Patent Documents 4 and 5, in a method for producing a hollow fiber membrane composed of a hydrophobic polymer and a hydrophilic polymer, a spinning stock solution is discharged downward from a nozzle and led to a coagulation bath through an air gap portion. In order to prevent defects and destruction of the membrane structure when the traveling direction is changed upward and pulled up from the coagulation bath, a technique for gradually changing the direction of the hollow fiber membrane is disclosed. However, this technique is different from the present technique in that the hollow fiber membrane traveling in the coagulation bath travels on a circumscribed track constituted by a plurality of direction changing guides.

JP 2006-239643 A Japanese Patent Laid-Open No. 7-39731 JP 2006-239576 A JP 2008-284471 A JP 2009-6230 A

  The present invention aims to solve such problems of the prior art, and specifically provides a method for stably producing a hollow fiber membrane having a relatively large inner diameter and film thickness. There is.

As a result of intensive studies to solve the above problems, the present inventors have found the following method for producing a hollow fiber membrane for liquid treatment.
(1) In a dry-wet spinning method in which a spinning stock solution composed of a polymer and a solvent is discharged from the outer annular part of a tube-in orifice nozzle, passes through an aerial traveling part, and is immersed in a coagulation bath to form a hollow fiber membrane. A hollow fiber membrane manufacturing method is characterized in that a hollow fiber membrane traveling in a bath travels along an inscribed track constituted by a guide group including a plurality of slack prevention guides.
(2) A method for producing a hollow fiber membrane, wherein the number of loosening prevention guides is 2 to 7.
(3) The contact of the slack prevention guide with which the hollow fiber membrane traveling in the coagulation bath first contacts is opposite to the direction in which the hollow fiber membrane is drawn from the 1-10 cm coagulation bath with respect to the vertical line of the tube-in orifice nozzle. It is the manufacturing method of the hollow fiber membrane characterized by being located.
(4) Production of a hollow fiber membrane characterized in that the contact point of the slack prevention guide with which the hollow fiber membrane traveling in the coagulation bath first comes into contact is located at a depth of 10 to 50 cm from the liquid surface of the coagulation bath. Is the method.
(5) A hollow fiber characterized in that the maximum immersion length, which is the shortest distance between the contact between the slack prevention guide located at the bottom of the coagulation bath and the hollow fiber membrane, and the coagulation bath liquid surface is 0.2 to 1 m. It is a manufacturing method of a film | membrane.

  By applying the method for producing a hollow fiber membrane of the present invention, the spinning region is greatly improved, so that the inner diameter and film thickness of the hollow fiber membrane can be easily made sufficiently large. That is, the hollow fiber membrane can be increased in diameter, and can be used for industrial applications such as microfiltration and ultrafiltration, and medical applications such as hemodialysis, hemofiltration, and hemodiafiltration. Even when a liquid to be treated containing a large amount of suspended solids is processed, the hollow fiber membrane that has little clogging at the inlet of the hollow fiber membrane, has high pressure resistance, and can maintain filtration performance for a long time is stabilized. Can be manufactured.

It is a process schematic diagram of an example of the manufacturing method of Example 1 (when four slack prevention guides are used). It is process schematic diagram of an example of the manufacturing method of Example 2 (when two slack prevention guides are used). It is process schematic diagram of an example of the manufacturing method of Comparative Examples 1 and 2. 2 is a SEM photograph (× 10000) of the inner surface of the hollow fiber membrane obtained in Example 1. FIG. 3 is a SEM photograph (× 10000) of the inner surface of the hollow fiber membrane obtained in Example 2. FIG. 3 is a SEM photograph (× 10000) of the inner surface of the hollow fiber membrane obtained in Comparative Example 1. 3 is a SEM photograph (× 10000) of the inner surface of the hollow fiber membrane obtained in Comparative Example 2.

  Hereinafter, the present invention will be described in detail.

  In the present invention, the spinning solution is discharged substantially vertically downward from the outer annular portion of the nozzle, and at the same time, the core solution is discharged from the center hole of the nozzle, and then the hollow spinning solution is guided to the coagulation bath through the aerial running portion and coagulated. In the dry-wet spinning method for phase separation, when a plurality of slack prevention guides and / or slack prevention rollers are installed in the coagulation bath to change the traveling direction of the hollow fiber membrane, a plurality of slack prevention guides and / or liquids are used. The hollow fiber membrane is caused to travel along an inscribed track constituted by a middle roller.

In the present invention, the material for the slack prevention guide and roller installed in the coagulation bath is not particularly limited, but Teflon (registered trademark), Bakelite (registered trademark), stainless steel, and the surface of the stainless steel is Teflon (registered trademark), silicon, Examples include those coated with hard chrome and the like. From the viewpoint of durability and reducing frictional resistance, the surface of the stainless steel round bar guide is preferably hard chrome coated and textured. Moreover, any of a fixed type and a free type may be sufficient, and a drive-type roller shape may be sufficient.
In addition, unlike the slack prevention guide method, a method of installing a bowl-shaped thing in the coagulation bath and running like a noodle sink can also be adopted. In the present invention, not only is the balance of the nozzle discharge linear speed and take-up speed of the spinning dope, gravitational acceleration, running resistance in the coagulation bath, and the specific gravity of the spinning dope high, so the hollow fiber membrane floats. It is possible to make it run stably on the roof without any trouble.

  When hollow fiber membranes are (dry) wet-spun, it is usually run around the outside (deeper side) of one or more slack prevention guides (submerged guides) installed in the coagulation bath. (See FIG. 3). However, if the amount of spinning solution discharged is increased in order to increase the inner diameter and the film thickness, the hollow fiber membrane running in the coagulation bath is slackened, and the phenomenon that the slackness gradually increases occurs. If stretching (draft) is applied in the coagulation bath to remove this slackness, there will be a problem that the inner diameter and the film thickness become smaller. However, even if the stretching (draft) is increased, the slackness cannot be solved. Will occur. The cause of this phenomenon is not well understood, but it seems to be related to the discharge amount of the spinning solution, the discharge linear velocity, gravity (acceleration), running resistance due to the coagulation liquid, and the like.

  As a result of intensive studies to suppress the slackness, the present inventor has observed the occurrence of slackness in the coagulation bath, and as a result, after the spinning stock solution discharged from the nozzle has entered the coagulation bath through the aerial running part In spite of applying the nozzle draft, it has been found that there is a characteristic that it swells in the direction opposite to the coagulation bath outlet direction (the left direction in FIGS. 1 and 2). Then it follows gravity and sinks towards the bottom of the coagulation bath. As a result of observing such a phenomenon, it is possible to stabilize even a large-diameter hollow fiber membrane by suppressing the force and gravity that swells in the direction opposite to the coagulation bath outlet direction applied to the hollow fiber membrane running in the coagulation bath. We thought that we could spin and finally reached the present invention.

  When processing fermented liquor such as wine and beer with a hollow fiber membrane module, it is generally performed by applying a high pressure of about 1 to 1.5 bar while flowing the fermented liquid through the hollow part of the hollow fiber membrane at a high flow rate. The fermentation liquor is purified by filtering from the inside to the outside of the hollow fiber membrane by crossflow filtration. At this time, the fermentation broth contains a large amount of suspended substances having a relatively large size. When such a liquid to be treated is treated with a hollow fiber membrane, a hollow having a relatively large diameter as described later is used. There is a need for a hollow fiber membrane that is a yarn membrane, has high filtration performance per unit membrane area, is less clogged at the inlet portion of the hollow fiber membrane, and has high pressure resistance.

  In order to increase the filtration performance, a method is generally employed in which the polymer concentration of the spinning dope is lowered and the solvent concentration of the core solution is increased. On the other hand, in order to reduce clogging at the entrance of the hollow fiber membrane, it is necessary to increase the inner diameter sufficiently. However, since the hollow ratio is lowered, the strength is weakened unless the film thickness is sufficiently increased. The membrane is damaged and cannot be used.

  However, if the hollow fiber membrane is to be spun in a condition where the polymer concentration in the spinning dope is relatively low and the solvent concentration of the core solution is relatively high in order to ensure the expected performance and quality, spinning is performed during the coagulation process. The hollow fiber membrane was loosened in the coagulation bath because the stock solution was stretched by its own weight, making spinning impossible, and the inner diameter and film thickness could not be increased sufficiently.

  The cause of the slack in the spinning solution discharged from the nozzle in the coagulation bath sinks downward due to the weight of the hollow fiber membrane solidified in the coagulation bath as described above. And since the downward force is transmitted to the spinning stock solution in a state where coagulation has not been completed in the aerial traveling part, the spinning stock solution in the aerial traveling part is stretched as a result. This is because the slack of the yarn membrane cannot be suppressed.

  As a result of diligent study to solve the above problems, the present inventors have stabilized the performance and quality while ensuring spinning stability by devising the elongation due to the weight of the spinning dope and the resistance due to the resistance of the coagulation liquid. The present invention was found out that it can be made. That is, in the present invention, in order to suppress the elongation of the spinning solution (hollow fiber membrane) applied to the nozzle to the coagulation bath, a plurality of guides or rollers are installed at important points in the coagulation bath, or a bowl-shaped jig is used. By installing the, a hollow fiber membrane can be formed while preventing elongation of the spinning dope (hollow fiber membrane) due to its own weight or resistance without applying excessive drawing (draft).

In the present invention, the position of the slack prevention guide or the contact of the submerged roller first contacted with the spinning solution (hollow fiber membrane) in the coagulation bath is 1-10 cm from the vertical downward line of the nozzle. It is preferably located on the side opposite to the drawing direction, more preferably 2 to 7 cm. As described above, the spinning dope that has entered the coagulation bath begins to slack in the direction opposite to the direction in which the hollow fiber membrane is pulled out of the coagulation bath against the flow of the coagulation solution, but before at least the surface of the spinning dope is solidified. When contacted with a guide or the like, there is a problem that the surface of the hollow fiber membrane is damaged or the smoothness of the curved surface of the outer surface shape is impaired (the outer surface is deformed). In other words, the spinning solution travels to some extent in the coagulation bath and needs to be brought into contact with a guide or the like after the surface is hardened. However, the spinning solution is slightly slackened in the direction opposite to the direction in which the hollow fiber membrane is drawn from the coagulation bath. Therefore, although it depends on the depth of the slack prevention guide, it is preferable to install in the above range. If it is smaller than 1 cm, the hollow fiber membrane pulled by the take-up roller cannot support the force going in the opposite direction. If it is larger than 10 cm, the force that sinks downward due to the weight of the hollow fiber membrane in the coagulation bath is Since the spinning solution is transferred to the spinning solution in a state where coagulation is not completed, the spinning solution in the aerial traveling section is stretched and the spinning solution in the aerial traveling section is greatly shaken, which may affect the spinnability and performance.
It is preferable that the depth from the coagulation bath liquid surface of the slack prevention guide with which the spinning dope comes into contact first in the coagulation bath is 10 to 30 cm. 15-25 cm is more preferable.

In the present invention, the maximum immersion length, which is the shortest distance from the contact between the slack prevention guide located at the deepest part of the coagulation bath and the hollow fiber membrane and the contact point to the coagulation bath liquid surface, is preferably 0.2 to 1 m. 0.3 to 0.8 m is more preferable, and 0.4 to 0.6 m is more preferable. If the length is shorter than 0.2 m, coagulation of the spinning dope is incomplete, and when the uncoagulated spinning dope (hollow fiber membrane) comes into contact with the slack prevention guide, crushing occurs, deformation of the outer surface shape, In some cases, a phenomenon may occur in which the film is separated into two layers at the cross section of the film. If it is larger than 1 m, there is a problem that workability deteriorates.
In addition, the contact between the guide and the hollow fiber membrane located in the deepest part of the coagulation bath is preferably located on the outlet side of the coagulation bath (the direction in which the hollow fiber membrane is drawn from the coagulation bath) from the vertical lower line of the nozzle, It is more preferable that the position is within about 30 cm from the vertical downward line, and more preferably within 20 cm. Although it depends on the running speed of the spinning dope (hollow fiber membrane), if it exceeds 30 cm, the slack due to its own weight cannot be eliminated and stable running may not be maintained.
In the present invention, the installation of the two guides described above is particularly important, and the other guides may be installed as many as necessary at necessary positions so that stable traveling can be performed while observing the traveling state.

  In the present invention, the plurality of slack prevention guides in the coagulation bath do not necessarily have to be entirely immersed in the coagulating liquid, and it is sufficient that the contact portion between the hollow fiber membrane and the guide is at least immersed in the coagulating liquid. Further, the position of the guide in the coagulation bath is not particularly limited, and it may be installed so that the desired angle of the hollow fiber membrane before and after each guide is obtained by the coagulation speed of the spinning dope.

  In the present invention, the discharge linear speed / coagulation bath first roller speed ratio (draft ratio) is preferably in the range of 0.9 to 1.8. If the ratio is less than 0.9, the take-off speed is too slow, and the slackness of the traveling hollow fiber membrane cannot be eliminated even if the present invention is applied. When the draft ratio exceeds 1.8, the pore shape of the hollow fiber membrane may be deformed. More preferably, it is 0.95-1.7, More preferably, it is 1.0-1.6, Most preferably, it is 1.05-1.5. By adjusting the draft ratio within this range, even a relatively large diameter hollow fiber membrane can be spun stably, and deformation and destruction of the pores can be prevented. It is possible to prevent clogging of objects, and to exhibit performance stability over time and sharp fractionation characteristics.

  The material of the hollow fiber membrane of the present invention is not particularly limited, and examples include cellulose, cellulose acetate, polymethyl methacrylate, polysulfone (PSf), polyethersulfone (PES), polyamide, polyethylene, polypropylene, and polyvinylidene fluoride. Polysulfone-based polymers such as polysulfone and polyethersulfone are particularly preferred because they can easily impart hydrophilicity with polyvinylpyrrolidone (PVP) or the like, and can obtain spinnability and sufficient permeation performance.

  Solvents used in the film-forming solution are N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP), N, N-dimethylformamide (hereinafter abbreviated as DMF), N, N-dimethylacetamide (hereinafter abbreviated as DMAc). ), Dimethyl sulfoxide (hereinafter abbreviated as DMSO), ε-caprolactam, etc., can be widely used as long as it is a good solvent for hydrophobic polymers and hydrophilic polymers. When a polysulfone polymer such as PSf or PES is used, a solvent such as NMP, DMF, or DMAc is preferable, and NMP is particularly preferable.

  In addition, a non-solvent for the polymer can be added to the spinning dope if necessary. Examples of the non-solvent used include ethylene glycol (hereinafter abbreviated as EG), propylene glycol (hereinafter abbreviated as PG), diethylene glycol (hereinafter abbreviated as DEG), triethylene glycol (hereinafter abbreviated as TEG), Examples include polyethylene glycol (hereinafter abbreviated as PEG), glycerin, water, and the like. When using a polysulfone polymer such as PSf or PES as a hydrophobic polymer, or PVP as a hydrophilic polymer, DEG, Ether polyols such as TEG and PEG are preferred, and TEG is more preferred.

The concentration of the hydrophobic polymer in the spinning stock solution is not particularly limited as long as film formation from the stock solution is possible, but is preferably 10 to 35% by weight, and more preferably 15 to 30% by weight. In order to obtain high permeability, the concentration of the hydrophobic polymer is preferably low, but if it is too low, the strength may be lowered, so 10 to 25% by weight is preferable.
The amount of hydrophilic polymer added is not particularly limited as long as it is sufficient to impart hydrophilicity to the hollow fiber membrane and suppress non-specific adsorption during aqueous fluid treatment. The polymer ratio is preferably 10 to 35% by weight, and more preferably 15 to 25% by weight. If the amount of the hydrophilic polymer added is too small, hydrophilicity imparting to the film may be insufficient, and the retention of the film characteristics may be reduced. Further, when the amount of the hydrophilic polymer added is too large, the hydrophilicity imparting effect is saturated and the efficiency is not good, and the phase separation (coagulation) of the spinning dope tends to proceed excessively. It may be disadvantageous to form the structure.

  The solvent / non-solvent ratio in the spinning dope is one of the important factors for controlling phase separation (coagulation) in the spinning process. Specifically, the content of the solvent / non-solvent is preferably 35/65 to 70/30 by weight, more preferably 40/60 to 60/40, and 45/55 to 50/50. More preferably. If the content of the solvent is too small, solidification tends to proceed, the membrane structure becomes too dense, and the permeability may decrease. On the other hand, if the solvent content is too high, the progress of phase separation is excessively suppressed and the pore diameter becomes too large, which may lead to a decrease in fractionation characteristics and strength.

As the composition of the core liquid used in forming the hollow fiber membrane, it is preferable to use a mixed solution of the same solvent, non-solvent, and water as used for the spinning dope. At this time, the ratio of the solvent and the non-solvent contained in the core liquid is preferably the same as the solvent / non-solvent ratio of the spinning dope. Preferably, the same solvent and non-solvent used in the spinning dope are mixed in the same ratio as in the spinning dope and diluted by adding water. By making the solvent / non-solvent composition of the spinning dope and the core solution the same, it is possible to reduce raw material procurement, manufacturing costs, and complexity of handling.
The content of water in the core liquid is preferably 10 to 20% by weight, more preferably 14 to 18% by weight. If the water content is too high, solidification tends to proceed, the membrane structure becomes too dense, and the permeability may decrease. If the water content is too low, the progress of phase separation is excessively suppressed and the pore size becomes too large, which may lead to a decrease in fractionation characteristics and strength, and the hollow fiber membrane relaxes in the coagulation bath. Therefore, even if the manufacturing method of the present invention is used, the inner diameter and the film thickness cannot be sufficiently increased.

The composition of the external coagulation liquid is preferably the same solvent, non-solvent and water mixture used for the spinning dope. At this time, the ratio of the solvent and the non-solvent contained in the core liquid is preferably the same as the solvent / non-solvent ratio of the spinning dope. Preferably, the same solvent and non-solvent used in the spinning dope are mixed in the same ratio as in the spinning dope and diluted by adding water. By making the solvent / non-solvent composition of the spinning dope, the core liquid, and the external coagulation liquid the same, it is possible to suppress the composition change of the external coagulation liquid, which is preferable from the viewpoint of manufacturing cost and management.
The content of water in the external coagulation liquid is preferably 30 to 85% by weight, more preferably 40 to 80% by weight. If the water content is too high, solidification tends to proceed, the membrane structure may become dense, and permeability may be reduced. On the other hand, if the water content is too small, the progress of phase separation is excessively suppressed and pores having a large pore diameter are likely to be generated, which may lead to a decrease in fractionation characteristics and strength.
In addition, if the temperature of the external coagulation liquid is too low, coagulation tends to proceed, and the membrane structure may be densified and the permeability may be reduced. On the other hand, if it is too high, the progress of phase separation is excessively suppressed, and pores having a large pore diameter are likely to be generated, which may cause a decrease in fractionation characteristics and strength. Therefore, the temperature of the external coagulation liquid is preferably 30 to 80 ° C, more preferably 40 to 70 ° C.

  In the present invention, the number of slack prevention guides installed in the coagulation bath is not particularly limited as long as the slack of the hollow fiber membrane running in the coagulation bath can be suppressed. Therefore, it is appropriate to set to 2-7. More preferably, it is 2-5.

  In the present invention, if the nozzle temperature is too low, solidification tends to proceed, the membrane structure may become too dense, and the permeability may decrease. On the other hand, if the viscosity is too high, the viscosity of the spinning dope becomes too low and stability in the aerial running section, and the weight of the hollow fiber membrane in the coagulation bath is transmitted and the uncoagulated spinning dope in the aerial running section is stretched, making spinning impossible. Sometimes. Furthermore, the progress of phase separation is excessively suppressed, and pores having a large pore diameter are likely to be generated, which may cause a decrease in fractionation characteristics and strength. Therefore, the nozzle temperature is preferably 40 to 70 ° C, more preferably 45 to 60 ° C.

  The inner diameter of the hollow fiber membrane of the present invention is preferably 700 to 2000 μm. Fine particles having a diameter of about 500 μm at the maximum may be present in the fermentation broth, and if the inner diameter is too small, the hollow portion of the hollow fiber membrane may be blocked. Therefore, the inner diameter of the hollow fiber membrane should be 800 μm or more. More preferred. 900 μm or more is more preferable, and 1000 μm or more is even more preferable. In addition, if the inner diameter is too large, it is necessary to increase the film thickness to maintain the hollow ratio in order to maintain pressure resistance, but if the film thickness is increased, the film thickness portion becomes resistant to the resistance when filtering the fermentation broth. Therefore, there is a possibility that a sufficient filtration flow rate cannot be obtained. In addition, when the spinning solution and the internal solution are discharged together from the nozzle and coagulated in the coagulation bath, coagulation becomes insufficient due to the large amount of spinning solution, and the hollow fiber membrane shape cannot be maintained. May end up. Furthermore, if the inner diameter is too large, the electric energy of the pump that flows the fermented liquor in order to obtain the linear velocity necessary for cross-flow filtration increases, which may increase the running cost. Accordingly, the inner diameter of the hollow fiber membrane is more preferably 1800 μm or less, further preferably 1700 μm or less, and even more preferably 1600 μm or less.

  The thickness of the hollow fiber membrane is preferably 200 to 500 μm, more preferably 250 to 350 μm. If the film thickness is too thin, the film may be damaged when the fermentation broth is filtered by applying a pressure of about 1.0 to 1.5 bar. When the film thickness is too thick, there is a possibility that a sufficient filtration flow rate cannot be obtained when the fermentation broth is filtered.

  As a nozzle for producing a hollow fiber membrane having an inner diameter and a film thickness as described above, a tube-in-orifice type nozzle is preferably used. In this case, the nozzle slit outer diameter is preferably 1000 to 3000 μm, and 1300 to 2800 μm. Is more preferable, and 1500 to 2500 μm is more preferable. The nozzle slit inner diameter is preferably 800 to 2000 μm, more preferably 1000 to 1700 μm. The slit width depends on the desired thickness of the hollow fiber membrane, but is preferably 500 to 1000 μm, more preferably 700 to 900 μm. When a nozzle having an excessively large slit width is used, it is necessary to increase the nozzle draft in order to obtain a desired film thickness, which may adversely affect the pore structure of the resulting hollow fiber membrane.

  The hollow ratio obtained by dividing the square of the inner diameter of the hollow fiber membrane by the square of the outer diameter is preferably 25 to 55%, more preferably 30 to 50%, and still more preferably 30 to 45%. When the hollow ratio is small, a module having a predetermined membrane area becomes large. If the hollow ratio is large, the strength of the membrane becomes weak and it cannot be used.

The hollow fiber membrane of the present invention preferably has a pure water permeation rate from the inside of the hollow fiber membrane to the outside of the hollow fiber membrane at a temperature of 22 ° C. and an operating pressure of 1 bar, more preferably 1000 to 5000 L / m ² / h / bar. the ^{1500~4500L / m 2 / h / bar} , more preferably from ^{2000~4000L / m 2 / h / bar} . If the permeation rate of pure water is too low, it may not be possible to obtain a sufficient fermentation broth filtration flow rate per unit membrane area. If the permeation rate of pure water is too high, the membrane may become weak and pressure resistance may be reduced.

  The burst pressure when measured by immersing the hollow fiber membrane of the present invention in pure water is 6.0 MPa or more, more preferably 7.0 MPa or more, still more preferably 8.0 MPa or more, and even more preferably 9.0 MPa or more. It is. When the fermentation broth is filtered, it is filtered with a pressure of about 1.0 to 1.5 bar, and the membrane may be damaged if the burst pressure is low. Since the fermented liquid contains about 10 to 20% alcohol, a burst pressure several times higher than the burst pressure measured with pure water is required. In addition, if the burst pressure is low, durability during repeated use is lowered.

In the present invention, the wine flux (10) 10 minutes after the start of filtration is preferably 50 L / m ² / h / bar or more, more preferably 70 L / m ² / h / bar or more, and 100 L / m ² / h / bar. The above is more preferable. The wine flux (120) 120 minutes after the start of filtration is preferably 30 L / m ² / h / bar or more, more preferably 50 L / m ² / h / bar or more. Wine Flux (10) indicates a point in time when a cake layer starts to be noticeably formed on the film surface, and wine Flux (120) indicates a state in which Flux has almost reached a stable state. That is, the wine flux retention (%) indicated by the ratio of wine flux (10) 10 minutes after the start of filtration and wine flux (120) 120 minutes after the start of filtration is preferably 40% or more, more preferably 45% or more. 50% or more is more preferable.

  In the present invention, it is necessary that a maximum pore exists in a scanning electron microscope (SEM) photograph of 10,000 times the inner surface of the hollow fiber membrane. In order to increase the Flux of wine filtration, it is necessary to increase the opening on the inner surface of the hollow fiber membrane to suppress the formation of the cake layer, but if there is no maximum pore on the inner surface, the wine is filtered and applied to the inner surface at the same time. A cake layer is formed and the wine flux decreases. The removal of the substance to be removed from the fluid by filtration has contributions from both the surface layer effect due to the pore diameter on the membrane surface and the depth effect due to the film thickness portion. Of these, separation that mainly depends on the depth effect can be expected to be sensitive to fractionation characteristics, and because it is separation using a certain thickness, there is an advantage that the influence of clogging is difficult to be manifested. In obtaining a yarn membrane, the method of the present invention is suitable.

  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 methods in the following examples are as follows.

1. Fabrication of mini-module Cut the hollow fiber membrane to about 40cm length, bundle both ends with vinyl tape to make a hollow fiber membrane bundle, and then end it with pliers in advance so that the end of the hollow fiber membrane opens after bonding The hollow part was closed by crushing the part. Both ends of the hollow fiber membrane bundle were inserted into pipes (sleeves), and an epoxy adhesive was poured into the pipes. After the epoxy resin was solidified, the end portion was cut to obtain a mini module having both ends opened. The number of hollow fiber membranes was appropriately set so that the surface area of the inner surface was 50 to 100 cm ² .

2. Production of Loop Type Mini-Module A hollow fiber membrane was cut into a length of about 40 cm to form a loop type, and then the ends were bundled with vinyl tape to produce a hollow fiber membrane bundle. After bonding, the end portion was crushed with pliers in advance so that the end portion of the hollow fiber membrane was opened, and then the end portion of the loop type hollow fiber membrane bundle was inserted into a pipe (sleeve), and the epoxy resin agent was poured into the pipe. After the epoxy resin was solidified, the end portion was cut to obtain a loop type minimodule having an open end portion. The number of hollow fiber membranes was set so that the surface area of the inner surface was 20 to 50 cm ² .

3. Calculation of membrane area The membrane area of the module was determined based on the inner diameter of the hollow fiber membrane. The module membrane area can be calculated by the following equation.
A = n × π × d × L
Here, n is the number of hollow fiber membranes, 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 fiber membrane in the module.

4). Measurement of pure water permeation rate (abbreviated as pure water Flux) A circuit is connected to two pipes at the ends of the mini module (referred to as the inner surface inlet and the inner surface outlet, respectively), and the inflow pressure of pure water into the module It was possible to measure the outflow pressure of pure water from the module. Pure water is introduced into the module from the inner surface inlet, the circuit connected to the inner surface outlet (downstream from the pressure measurement point) is closed to stop the flow, and the pure water entered from the inner surface inlet of the module is totally filtered. did. Pure water kept at 22 ° C. was placed in a pressurized tank, and while controlling the pressure with a regulator, pure water was sent to the mini module, and the amount of filtrate flowing out from the dialysate outlet was measured. The transmembrane pressure difference (TMP) is
TMP = (Pi + Po) / 2
It was. Here, Pi is the inner surface inlet side pressure of the module, and Po is the inner surface outlet side pressure of the module. The pure water flux of the hollow fiber membrane was calculated from the membrane area and the water permeability of the module.
Pure water Flux [L / m ² / h / bar]
= (Filtration volume of pure water per minute [L / min] x 60 / A / TMP [bar]
Here, pure water Flux is the water permeability [L / m ² / h / bar] of the hollow fiber membrane, and A is the membrane area [m ² ] of the module.

5. Measurement of wine permeability (abbreviated as Wine Flux) The turbid wine containing yeast marketed by Tamba Wine Co., Ltd. “Tamba Shinshu Nigori 2005” is marketed by Mercian Co., Ltd. It was diluted with “wine life [white]” and adjusted to have a turbidity of 10 NTU (hereinafter referred to as evaluation wine). After immersing the module in RO water for 1 hour or more, the module was replaced with evaluation wine, and both the inner and outer surfaces were filled with the evaluation wine. The container was filled with wine for evaluation and the temperature was controlled to 22 ° C. A circuit was constructed so that the evaluation wine perfused the inner surface of the mini-module from the container through the pump and returned to the container, and the evaluation wine filtered by the hollow fiber membrane also returned to the container. At that time, the inflow pressure of the evaluation wine to the module and the outflow pressure of the evaluation wine from the module can be measured. The evaluation wine was introduced from the inner surface inlet so that the evaluation wine flowed through the lumen of the hollow fiber membrane at a flow rate of 1.5 m / sec. At this time, TMP was adjusted to about 1.5 bar. In this state, the evaluation wine was perfused into the lumen of the hollow fiber membrane, and cross-flow filtration for filtering a part was continued. When a predetermined time has elapsed, the amount of wine filtered in a certain time was measured (for example, the filtration amount at the time point of 10 to 11 minutes after the start of perfusion, and the filtration amount at the time point of 20 to 21 minutes). Wine Flux was calculated by the following formula.
Wine Flux [L / m ² / h / bar]
= (Wine filtration per minute [L / min] x 60 / A / TMP [bar]
However, A is the membrane area [m ² ] of the module.

6). Measurement of inner diameter and film thickness of hollow fiber membrane The hollow fiber membrane is cut with a sharp razor perpendicular to the length direction, and the cross section is observed with a 20-fold microscope. And measure the average value.
Film thickness [μm] = {(outer diameter) − (inner diameter)} / 2

7). Burst pressure A circuit was connected to the loop mini-module, and the mini-module was immersed in pure water for 5 minutes, and then pressurized with an air cylinder at a rate of 1 bar per minute, and the pressure at which the mini-module burst was measured.

Example 1
19.0 parts by weight of PES (Sumitomo Chemtec (registered trademark) 5200P) manufactured by Sumitomo Chemtech, 5.0 parts by weight of PVP (Koridon (registered trademark) K30) manufactured by BASF, 34.2 parts by weight of NMP manufactured by Mitsubishi Chemical, TEG41 manufactured by Mitsui Chemicals. 8 parts by weight were mixed and dissolved at 80 ° C. for 3 hours to obtain a uniform solution. The resulting solution was depressurized to normal pressure -0.05 MPa and then allowed to stand for 3 hours for defoaming, and this solution was used as a spinning dope. On the other hand, a mixed solution of 37.8 parts by weight of NMP, 46.2 parts by weight of TEG, and 16.0 parts by weight of RO water was prepared, and this solution was used as a core solution. The spinning stock solution is discharged at 19.1 cc / min / weight from the outer annular part of the double-tube nozzle, and the core liquid is discharged at 11.7 cc / min / weight from the center part. After passing through a 15 mm air gap, 13.5 parts by weight of NMP , Led to a coagulation bath filled with an external coagulation liquid consisting of a mixture of 16.5 parts by weight of TEG and 70.0 parts by weight of RO water. At this time, the nozzle temperature was set to 65 ° C., and the external coagulating liquid temperature was set to 55 ° C. The nozzle used had a slit outer diameter of 2300 μm and a slit inner diameter of 1500 μm. In the coagulation liquid, four slack prevention guides having a radius of 12 mm were used, and the traveling direction was changed so that the hollow fiber membranes were in contact with the slack prevention guides as shown in FIG. At this time, each guide was installed at a position shown in Table 1. In the table, the lateral position represents the distance from the vertical downward line from the nozzle, and the direction in which the hollow fiber membrane is drawn out from the coagulation bath is plus, and if it is located in the opposite direction, it is minus. On the other hand, the vertical position represents the distance from the coagulation bath liquid surface. Further, the four slack prevention guides used were a stainless steel round bar guide whose surface was hard chrome coated and textured. The hollow fiber membrane was drawn out from the coagulation bath, passed through a water washing tank, and after removing excess solvent, it was rolled up at a spinning speed of 8.2 m / min. The hollow fiber membrane bundle wound up in a kite was cut to a predetermined length to form a bundle, and the liquid contained in the hollow portion of the hollow fiber membrane was removed by extending the bundle vertically. The bundle was immersed in RO water at 85 ° C. for 60 minutes for heat treatment, and then dried with hot air at 60 ° C. for 10 hours. The obtained dry hollow fiber membrane had an inner diameter of 1210 μm and a film thickness of 349 μm.

  Maximum pores were observed on the inner surface of the obtained hollow fiber membrane by SEM observation at a magnification of 10,000 times. A mini-module was made from the obtained hollow fiber membrane, and the wine flux was measured. The wine flux measured after 10 minutes (10), the wine flux measured after 120 minutes (120) to the wine flux (10) / wine flux. When (120) × 100 = retention rate (%) was determined, it showed high wine flux performance. The results are summarized in Table 2.

(Example 2)
19.0 parts by weight of PES (Sumitomo Chemtech (registered trademark) 4800P manufactured by Sumitomo Chemtech), 7.0 parts by weight of PVP (Koridon (registered trademark) K30) manufactured by BASF, 33.3 parts by weight of NMP manufactured by Mitsubishi Chemical, and TEG40 manufactured by Mitsui Chemicals. 7 parts by weight were mixed and dissolved at 72 ° C. for 3 hours to obtain a uniform solution. The resulting solution was depressurized to normal pressure -0.05 MPa and allowed to stand for 3 hours for defoaming. This solution was used as the spinning dope. On the other hand, a mixed solution of 37.8 parts by weight of NMP, 46.2 parts by weight of TEG, and 16.0 parts by weight of RO water was prepared, and this solution was used as a core solution. The spinning solution is discharged from the annular part of the double pipe nozzle at 25.3 cc / min / weight, and the core liquid is discharged from the center part at 15.2 cc / min / weight, passing through a 15 mm air gap, 13.5 parts by weight of NMP, The solution was introduced into a coagulation bath filled with an external coagulation liquid consisting of a mixture of 16.5 parts by weight of TEG and 70.0 parts by weight of RO water. At this time, the nozzle temperature was set to 60 ° C., and the external coagulation liquid temperature was set to 65 ° C. The nozzle used had a slit outer diameter of 2300 μm and a slit inner diameter of 1500 μm. In the coagulation liquid, two slack prevention guides having a radius of 15 mm were used, and the travel direction was changed by running so that the hollow fiber membrane was in contact with the slack prevention guides as shown in FIG. The position of each guide is shown in Table 1. The two slack prevention guides were stainless steel round bar guides. The hollow fiber membrane was drawn out from the coagulation bath, passed through a water washing tank, and after removing excess solvent, it was rolled up at a spinning speed of 8.2 m / min. The hollow fiber membrane bundle wound up in a kite was cut to a predetermined length to form a bundle, and the liquid contained in the hollow portion of the hollow fiber membrane was removed by extending the bundle vertically. The bundle was immersed in 80 ° C. RO water for 60 min and heat-treated, and then dried with hot air at 60 ° C. for 10 hours. The obtained dry hollow fiber membrane had an inner diameter of 1985 μm and a film thickness of 493 μm. A maximum pore was seen on the inner surface in a 10,000 times SEM photograph. The results are shown in Table 2.

(Example 3)
19.0 parts by weight of PES (Sumitomo Chemtec (registered trademark) 5200P) manufactured by Sumitomo Chemtech, 5.0 parts by weight of PVP (Koridon (registered trademark) K30) manufactured by BASF, 34.2 parts by weight of NMP manufactured by Mitsubishi Chemical, TEG41 manufactured by Mitsui Chemicals. 8 parts by weight were mixed and dissolved at 80 ° C. for 3 hours to obtain a uniform solution. The resulting solution was depressurized to normal pressure -0.05 MPa and then allowed to stand for 3 hours for defoaming, and this solution was used as a spinning dope. On the other hand, a mixed solution of 37.8 parts by weight of NMP, 46.2 parts by weight of TEG, and 16.0 parts by weight of RO water was prepared, and this solution was used as a core solution. The spinning solution is discharged at 16.4 cc / min / weight from the annular part of the double-tube nozzle, and the core liquid is discharged at 11.7 cc / min / weight from the central part, and through an air gap of 15 mm, 13.5 parts by weight of NMP, The solution was introduced into a coagulation bath filled with an external coagulation liquid consisting of a mixture of 16.5 parts by weight of TEG and 70.0 parts by weight of RO water. At this time, the nozzle temperature was set to 65 ° C., and the external coagulating liquid temperature was set to 55 ° C. The nozzle used had a slit outer diameter of 2300 μm and a slit inner diameter of 1500 μm. In the coagulation liquid, four slack prevention guides having a radius of 12 mm were used, and the traveling direction was changed so that the hollow fiber membranes were in contact with the slack prevention guides as shown in FIG. The position of each guide is shown in Table 1. In addition, four slack prevention guides having a satin finish on the surface were used. The hollow fiber membrane was drawn out from the coagulation bath, passed through a water washing tank, and after removing excess solvent, it was rolled up at a spinning speed of 8.2 m / min. The hollow fiber membrane bundle wound up in a kite was cut to a predetermined length to form a bundle, and the liquid contained in the hollow portion of the hollow fiber membrane was removed by extending the bundle vertically. The bundle was immersed in RO water at 85 ° C. for 60 minutes for heat treatment, and then dried with hot air at 60 ° C. for 10 hours. The obtained dry hollow fiber membrane had an inner diameter of 1150 μm and a film thickness of 206 μm. A maximum pore was seen on the inner surface in a 10,000 times SEM photograph. The results are summarized in Table 2.

Example 4
19.0 parts by weight of PES (Sumitomo Chemtech (registered trademark) 4800P manufactured by Sumitomo Chemtech), 7.0 parts by weight of PVP (Koridon (registered trademark) K30) manufactured by BASF, 33.3 parts by weight of NMP manufactured by Mitsubishi Chemical, and TEG40 manufactured by Mitsui Chemicals. 7 parts by weight were mixed and dissolved at 72 ° C. for 3 hours to obtain a uniform solution. The resulting solution was depressurized to normal pressure -0.05 MPa and allowed to stand for 3 hours for defoaming. This solution was used as the spinning dope. On the other hand, a mixed solution of 37.8 parts by weight of NMP, 46.2 parts by weight of TEG, and 16.0 parts by weight of RO water was prepared, and this solution was used as a core solution. The spinning stock solution is discharged at 18.5 cc / min / weight from the annular part of the double-tube nozzle, and the core liquid is discharged at 7.3 cc / min / weight from the center part, and through an air gap of 15 mm, 13.5 parts by weight of NMP, The solution was introduced into a coagulation bath filled with an external coagulation liquid consisting of a mixture of 16.5 parts by weight of TEG and 70.0 parts by weight of RO water. At this time, the nozzle temperature was set to 59.1 ° C., and the external coagulating liquid temperature was set to 63.7 ° C. The nozzle used had a slit outer diameter of 1500 μm and a slit inner diameter of 1000 μm. In the coagulation liquid, two slack prevention guides having a radius of 15 mm were used, and the traveling direction was changed so that the hollow fiber membranes were in contact with the slack prevention guides as shown in FIG. The position of each guide is shown in Table 1. In addition, two slack prevention guides having a textured surface were used. The hollow fiber membrane was drawn out from the coagulation bath, passed through a water washing tank, and after removing excess solvent, it was rolled up at a spinning speed of 8.2 m / min. The hollow fiber membrane bundle wound up in a kite was cut to a predetermined length to form a bundle, and the liquid contained in the hollow portion of the hollow fiber membrane was removed by extending the bundle vertically. The bundle was immersed in 80 ° C. RO water for 60 min and heat-treated, and then dried with hot air at 60 ° C. for 10 hours. The obtained dry hollow fiber membrane had an inner diameter of 703 μm and a film thickness of 349 μm. A maximum pore was seen on the inner surface in a 10,000 times SEM photograph. The results are shown in Table 2.

(Example 5)
19.0 parts by weight of PES (Sumitomo Chemtec (registered trademark) 5200P) manufactured by Sumitomo Chemtech, 5.0 parts by weight of PVP (Koridon (registered trademark) K30) manufactured by BASF, 34.2 parts by weight of NMP manufactured by Mitsubishi Chemical, TEG41 manufactured by Mitsui Chemicals. 8 parts by weight were mixed and dissolved at 80 ° C. for 3 hours to obtain a uniform solution. The resulting solution was depressurized to normal pressure -0.05 MPa and then allowed to stand for 3 hours for defoaming, and this solution was used as a spinning dope. On the other hand, a mixed solution of 37.8 parts by weight of NMP, 46.2 parts by weight of TEG, and 16.0 parts by weight of RO water was prepared, and this solution was used as a core solution. The spinning solution is discharged from the annular part of the double pipe nozzle at 20.7cc / min / weight, and the core liquid is discharged from the center part at 12.0cc / min / weight, passing through a 15mm air gap, NMP13.5 parts by weight, The solution was introduced into a coagulation bath filled with an external coagulation liquid consisting of a mixture of 16.5 parts by weight of TEG and 70.0 parts by weight of RO water. At this time, the nozzle temperature was set to 65 ° C., and the external coagulating liquid temperature was set to 55 ° C. The nozzle used had a slit outer diameter of 2300 μm and a slit inner diameter of 1500 μm. In the coagulation liquid, four slack prevention guides having a radius of 12 mm were used, and the traveling direction was changed so that the hollow fiber membranes were in contact with the slack prevention guides as shown in FIG. The position of each guide is shown in Table 1. In addition, four slack prevention guides having a satin finish on the surface were used. The hollow fiber membrane was drawn out from the coagulation bath, passed through a water washing tank, and after removing excess solvent, it was rolled up at a spinning speed of 8.2 m / min. The hollow fiber membrane bundle wound up in a kite was cut to a predetermined length to form a bundle, and the liquid contained in the hollow portion of the hollow fiber membrane was removed by extending the bundle vertically. The bundle was immersed in RO water at 85 ° C. for 60 minutes for heat treatment, and then dried with hot air at 60 ° C. for 10 hours. The obtained dry hollow fiber membrane had an inner diameter of 1230 μm and a film thickness of 433 μm. A maximum pore was seen on the inner surface in a 10,000 times SEM photograph. The results are summarized in Table 2.

(Example 6)
19.0 parts by weight of PES (Sumitomo Chemtech (registered trademark) 4800P manufactured by Sumitomo Chemtech), 7.0 parts by weight of PVP (Koridon (registered trademark) K30) manufactured by BASF, 33.3 parts by weight of NMP manufactured by Mitsubishi Chemical, and TEG40 manufactured by Mitsui Chemicals. 7 parts by weight were mixed and dissolved at 72 ° C. for 3 hours to obtain a uniform solution. The resulting solution was depressurized to normal pressure -0.05 MPa and then allowed to stand for 3 hours for defoaming, and this solution was used as a spinning dope. On the other hand, a mixed solution of 37.8 parts by weight of NMP, 46.2 parts by weight of TEG, and 16.0 parts by weight of RO water was prepared, and this solution was used as a core solution. The spinning solution is discharged at 17.8 cc / min / weight from the annular part of the double tube nozzle, and the core liquid is discharged at 13.6 cc / min / weight from the center part, and through an air gap of 15 mm, 13.5 parts by weight of NMP, The solution was introduced into a coagulation bath filled with an external coagulation liquid consisting of a mixture of 16.5 parts by weight of TEG and 70.0 parts by weight of RO water. At this time, the nozzle temperature was set to 59.1 ° C., and the external coagulating liquid temperature was set to 63.7 ° C. The nozzle used had a slit outer diameter of 2500 μm and a slit inner diameter of 1700 μm. In the coagulation liquid, four slack prevention guides having a radius of 15 mm were used, and the traveling direction was changed so that the hollow fiber membranes were in contact with the slack prevention guides as shown in FIG. The position of each guide is shown in Table 1. In addition, four slack prevention guides having a satin finish on the surface were used. The hollow fiber membrane was drawn out from the coagulation bath, passed through a water washing tank, and after removing excess solvent, it was rolled up at a spinning speed of 8.2 m / min. The hollow fiber membrane bundle wound up in a kite was cut to a predetermined length to form a bundle, and the liquid contained in the hollow portion of the hollow fiber membrane was removed by extending the bundle vertically. The bundle was immersed in 80 ° C. RO water for 60 min and heat-treated, and then dried with hot air at 60 ° C. for 10 hours. The obtained dry hollow fiber membrane had an inner diameter of 1533 μm and a film thickness of 265 μm. A maximum pore was seen on the inner surface in a 10,000 times SEM photograph. The results are shown in Table 2.

(Comparative Example 1)
As shown in FIG. 3, spinning was performed under the same conditions as in Example 1 except that the hollow fiber membrane was run in the outer peripheral direction opposite to the double tube cap of the slack preventing guide using one slack preventing guide. The sagging prevention guide was installed at a position of a depth of 45 cm from the coagulation bath liquid surface on the vertical downward line of the nozzle. When the discharge rate of the spinning solution was increased while maintaining the inner diameter at 1200 μm, the hollow fiber membrane loosened in the coagulation liquid at about 10 cc / min / weight, and the film thickness could not be increased any more. . The obtained dry hollow fiber membrane had an inner diameter of 1252 μm and a film thickness of 187 μm. When wine Flux was measured, the measurement was stopped as soon as the measurement was started and the membrane was damaged. The results are shown in Table 2.

(Comparative Example 2)
19.0 parts by weight of PES (Sumitomo Chemtech (registered trademark) 4800P manufactured by Sumitomo Chemtech), 3.0 parts by weight of PVP (Koridon (registered trademark) K30) manufactured by BASF, 35.1 parts by weight of NMP manufactured by Mitsubishi Chemical, and TEG42 manufactured by Mitsui Chemicals. 9 parts by weight were mixed and dissolved at 80 ° C. for 4 hours to obtain a uniform solution. Furthermore, after reducing the pressure to normal pressure -0.05 MPa, the system was immediately sealed so that the solvent composition would not volatilize and the solution composition would not change, and left for 3 hours to degas, and this solution was used as the spinning dope. . On the other hand, a mixed solution of 34.875 parts by weight of NMP, 42.625 parts by weight of TEG, and 22.5 parts by weight of RO water was prepared, and this solution was used as a core solution. The spinning solution is discharged from the annular part of the double tube nozzle, the core liquid is discharged from the center part, and after passing through an air gap of 20 mm, a mixed liquid of NMP 13.5 parts by weight, TEG 16.5 parts by weight, RO water 70.0 parts by weight Led to a coagulation bath filled with an external coagulation liquid. At this time, the nozzle temperature was set to 72 ° C., and the external coagulation liquid temperature was set to 55 ° C. The nozzle used had a slit outer diameter of 1000 μm and a slit inner diameter of 800 μm. As shown in FIG. 3, the hollow fiber membrane was run on the outside (lower side) of the slack prevention guide using one slack prevention guide. Further, the hollow fiber membrane was drawn out from the coagulation bath, passed through a washing tank for 45 seconds to remove excess solvent, and then spun at a spinning speed of 8.2 m / min. The hollow fiber membrane bundle that has been wound up on the scissors is left as it is for 40 minutes, and then both ends of the scissors are taped, and the outside of the tape is cut with a cutter so that the cross section of the hollow fiber membrane is not crushed, and then the bundle is hollowed vertically. The liquid contained in the hollow part of the yarn membrane was removed. The hollow fiber membrane bundle was immersed in 80 ° C. RO water for 60 minutes and heat-treated, and then dried with hot air at 60 ° C. for 10 hours to obtain a hollow fiber membrane having an inner diameter of 561 μm and a film thickness of 84 μm.

  No maximum pores were observed on the inner surface in a 10,000 times SEM photograph. When the wine flux was measured, the value was low and could not be used in the actual filtration process.

  The polymer porous hollow fiber membrane of the present invention is used in the field of food, medicine, semiconductor, energy and water treatment, and the hollow fiber membrane is used for industrial applications such as microfiltration and ultrafiltration. It can be widely used for medical applications such as hemodialysis, hemofiltration, and hemodiafiltration. In particular, it is suitable as a hollow fiber membrane for liquid processing used for fermentation broth in the food field for the removal of wine, yeast in beer, solids, colloids and the like.

1 Double tube cap 2-1 Anti-sagging guide or roller in coagulation bath 2-2 Anti-sagging guide or roller in coagulation bath 2-3 Anti-sagging guide or roller in coagulation bath 2-4 Anti-sagging in coagulation bath Guide or roller 3 Coagulation bath 4 Aerial running part 5 Hollow fiber membrane 6 Take-off roller 7 Slack prevention guide or touch roller located at the bottom and the distance between the contact point of the hollow fiber membrane and the shortest coagulation bath liquid surface

Claims (5)

  In the dry-wet spinning method, in which a spinning stock solution composed of a polymer and a solvent is discharged from the outer annular portion of the tube-in orifice nozzle, passes through the aerial running portion, and is immersed in the coagulation bath to form a hollow fiber membrane. A method for producing a hollow fiber membrane, characterized in that the traveling track of the traveling hollow fiber membrane travels along an inscribed track constituted by a guide group composed of a plurality of slack prevention guides.   The method for producing a hollow fiber membrane according to claim 1, wherein the number of loosening prevention guides is 2-7.   The contact point of the slack prevention guide with which the hollow fiber membrane traveling in the coagulation bath first contacts is located on the side opposite to the direction in which the hollow fiber membrane is drawn from the 1-10 cm coagulation bath with respect to the vertical line of the tube-in orifice nozzle. The method for producing a hollow fiber membrane according to claim 1 or 2.   The contact point of the slack prevention guide with which the hollow fiber membrane traveling in the coagulation bath first contacts is installed at a position 10 to 30 cm deep from the liquid level of the coagulation bath. The manufacturing method of the hollow fiber membrane of description. 5. The maximum immersion length, which is the shortest distance between the contact between the slack prevention guide located at the bottom of the coagulation bath and the hollow fiber membrane and the liquid level of the coagulation bath, is 0.2 to 1 m. The manufacturing method of the hollow fiber membrane in any one.