JPH10216488A - Hollow fiber type selective separation membrane and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane having high chemical resistance and physical strength which does not cause decrease in the separation function and flowing of hydrophilic polymers from the membrane even when the membrane is subjected to chemical treatment or reverse washing for regeneration treatment. SOLUTION: This separation membrane contains hydrophobic polymers and hydrophilic polymers and has a uniform membrane structure. The ratio of the sieve factor of the membrane for β2 -microglobulin before the treatment with a rhenolin soln. to the sieve factor for β2 -microglobulin after the treatment with rhenolin soln. is >=80%. This hollow fiber selective separation membrane is produced by a dry and wet spinning method using a spinning source liquid having 100 to 500 poise viscosity at 140 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber type selective separation membrane (hereinafter, also referred to as a hollow fiber membrane) and a method for producing the same. The present invention relates to a hollow fiber type selective separation membrane excellent in chemical resistance and physical strength at the time of back washing, and a method for producing the same.

[0002]

2. Description of the Related Art At present, various types of hollow fiber membranes are used for dialysis and filtration of various liquids such as suspensions and blood. However, dirt due to adhesion of liquid or solid solute components is used. And clogging easily occur. Since hollow fiber membranes are often expensive in cost, it is desirable to use them continuously or a plurality of times. Therefore, it is necessary to regenerate them to eliminate dirt and clogging and make them usable again. It is. Examples of the method of regenerating the hollow fiber membrane include a method of dissolving and washing a solute attached by a chemical and a method of removing the solute attached by back washing.In these methods, the hollow fiber membrane has a chemical resistance or It is necessary to have physical strength.

As a hollow fiber membrane excellent in chemical resistance and physical strength, a hollow fiber membrane made of a synthetic polymer such as polysulfone or polyolefin is known, but these are all hydrophobic membranes. Yes, it has the disadvantage that it is easily stained during use.

As a hollow fiber membrane intended to solve such a defect, for example, US Pat.
No. 93801, JP-A-58-104940, etc., by coexisting a hydrophilic polymer with a hydrophobic polymer, the hydrophobic polymer has chemical resistance and physical strength, and the membrane is hydrophilic. There is disclosed a hollow fiber membrane which is formed into a film to reduce the possibility of soiling.

However, each of these hollow fiber membranes is a hollow fiber membrane having an asymmetric structure, and is composed of a skin layer having a dense structure and a support layer forming voids having a relatively large pore diameter. In the case of chemical treatment or backwashing at the time of the regeneration treatment, the hydrophilic polymer is eluted from a portion of the support layer having a large pore diameter, and there is a disadvantage that the separation performance of the membrane is reduced.

On the other hand, for example, Japanese Patent Publication No. 6-7566
7, JP-A-5-3331, JP-A-4-30
No. 0636 and JP-A-6-238139 disclose a hollow fiber membrane in which a hydrophilic polymer is insolubilized by subjecting the hydrophilic polymer to a crosslinking treatment. However, even with these hollow fiber membranes, although varying in degree, elution of the water-soluble polymer due to chemical treatment or backwashing cannot be sufficiently prevented, and a decrease in separation performance of the membrane cannot be avoided.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and has as its object the purpose of having high chemical resistance and physical strength, chemical treatment for regenerating treatment and backwashing. The present invention provides a hollow fiber membrane in which the hydrophilic polymer does not flow out of the membrane and the separation performance does not decrease even when the method is performed, and a method for producing the same.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies on the composition and structure of a hollow fiber membrane. As a result, a hydrophobic polymer having chemical resistance and physical strength was obtained. By using a hydrophilic polymer that improves the separation performance of the membrane and dirt during use, the entire membrane has a dense and uniform structure, and the structure in which the hydrophilic polymer is confined in that structure, It has been found that even if chemical treatment or backwashing is performed, the separation performance can be maintained while the hydrophilic polymer is retained in the membrane structure.

In addition, the inventors of the present invention spin by using a spinning dope in which the concentration of the polymer in the spinning dope and the viscosity of the spinning dope are within specific ranges, so that the coagulation into the spinning dope during coagulation is performed. It has also been found that a hollow fiber membrane that can achieve the object of the present invention can be obtained by delaying the infiltration of the solution and slowing down the gelation rate of the spinning solution.

That is, the present invention is as follows. (1) A hollow fiber type selected separation membrane containing a hydrophobic polymer and a hydrophilic polymer, has a uniform film structure, beta ₂ of the pretreatment with Renarin liquid - against microglobulin sieving coefficient, Renarin A hollow fiber type selective separation membrane, wherein the ratio of the sieving coefficient of β ₂ -microglobulin after the treatment with the liquid is 80% or more. (2) The hollow fiber type selective separation membrane according to the above (1), wherein the ratio of the elongation at break after treatment with the renalin solution to the elongation at break before treatment with the renalin solution is 80% or more. (3) The hollow fiber type selective separation membrane according to (1), wherein the ratio of the water permeation rate after the treatment with the renaline liquid to the water permeation rate before the treatment with the renaline liquid is 80% or more. (4) The hollow fiber type selective separation membrane according to any one of the above (1) to (3), wherein the hydrophobic polymer is a polysulfone polymer or a polyether sulfone polymer. (5) The hydrophilic polymer is polyvinylpyrrolidone
The hollow fiber type selective separation membrane according to any one of (1) to (4). (6) The polymerization average molecular weight of the hydrophilic polymer is 45,000 to 11
The hollow fiber type selective separation membrane according to any one of the above (1) to (5), wherein the membrane is 00000.

(7) A hollow fiber type selective separation in which a spinning solution containing a hydrophobic polymer, a hydrophilic polymer, and a solvent is discharged in a gaseous atmosphere so as to form a hollow shape, and then guided to a coagulation bath for coagulation. A method for producing a membrane, comprising:
A method for producing a hollow fiber type selective separation membrane, wherein the viscosity at 0 ° C. is 100 to 500 poise. (8) The viscosity at 140 ° C. of the spinning dope is 120 to 400.
The method for producing a hollow fiber type selective separation membrane according to the above (7), which is a poise. (9) The method for producing a hollow fiber type selective separation membrane according to (7) above, wherein the hydrophilic polymer is contained in the spinning solution at 0.5 to 10% by weight. (10) The hydrophilic polymer has a polymerization average molecular weight of 45,000 to 110
(7) The process for producing a hollow fiber type selective separation membrane according to the above (7), wherein the polyvinylpyrrolidone is 0000, and the polyvinylpyrrolidone is contained in the spinning solution at 0.5 to 10% by weight.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The hollow fiber membrane of the present invention contains a hydrophobic polymer and a hydrophilic polymer.

As the hydrophobic polymer used in the present invention, a hydrophobic polymer which can be generally used as a material for a hollow fiber membrane can be used. Examples thereof include polysulfone, polyaramid, polyethersulfone, polyamide, polycarbonate, and the like. Examples include polymers such as polyvinyl chloride, polyether, polyurethane, polypropylene, polyetherimide, and polyacrylonitrile. Among them, polysulfone-based and polyethersulfone-based polymers are excellent in chemical resistance and mechanical strength. Is preferred.

The polysulfone or polyethersulfone polymer used in the present invention is not particularly limited. For example, polysulfone represented by the following general formula (I) or polysulfone represented by the following formula (II) Ethersulfone is commercially available. There are several types of these polymer compounds depending on the degree of polymerization and the like, but there is no particular limitation.

[0015]

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[0016]

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As the hydrophilic polymer used in the present invention, a hydrophilic polymer which can be generally used as a material for a hollow fiber membrane can be used. For example, polyvinylpyrrolidone,
Examples include polyvinyl alcohol and polyethylene glycol. There are several types of these hydrophilic polymers depending on the degree of polymerization and the like, and polymers having any molecular weight can be used.However, the higher the molecular weight, the greater the degree of retention in the hollow fiber membrane. 45000-1100
It is preferred to use polymers in the range of 000.

The hollow fiber type selective separation membrane of the present invention has a uniform membrane structure. The uniform film structure in the present invention is:
It refers to a film structure that has no clear skin / core asymmetric structure and in which no pores and voids are clearly observed in the film cross section when the film cross section is observed with an electron microscope at 1000 ×.

In the hollow fiber type selective separation membrane of the present invention,
Of pretreatment with Renarin liquid beta ₂ - microglobulin (hereinafter, beta ₂ -MG also called) for sieving coefficients, beta ₂ following treatment with Renarin solution - the ratio of microglobulin sieving coefficient of 80% or more, preferably 90 %, More preferably 95% or more. When this ratio is less than 80%, the original separation function is not exhibited even if the regeneration process is performed, and the device cannot be used continuously or a plurality of times.

In the present invention, the term “renaline liquid” refers to a liquid composed of 17% by weight of aqueous hydrogen peroxide, 9% by weight of peracetic acid, 7% by weight of acetic acid, and 67% by weight of water. The treatment with the renalin solution means that the treatment with the sterile water, the treatment with the renalin solution, and the treatment with the sterile water are sequentially performed.

It should be noted that β ₂ -microglobulin (molecular weight 1)
1600) is considered a causative agent of carpal tunnel syndrome, a hollow fiber type selected separation membrane of the present invention the beta ₂ - is required to be excellent in microglobulin removability. Specifically, it has a sieving coefficient of β ₂ -microglobulin of preferably 0.50 or more, more preferably 0.60 or more, and particularly preferably 0.70 or more. The sieving coefficient of β ₂ -microglobulin is represented by the following equation. As a measurement stock solution,
Using 0.01% by weight β ₂ -microglobulin-phosphate buffer (pH 7.2), the concentration of the stock solution at the inlet, the concentration of the test solution at the outlet, and the concentration of the filtrate at the outlet of the 8500 bundle module were measured. , The sieving coefficient SC is calculated. SC = (2 × filtrate concentration) / (inlet concentration + outlet concentration)

In the hollow fiber type selective separation membrane of the present invention, the ratio of the breaking elongation after the treatment with the renalin solution to the breaking elongation before the treatment with the renalin solution is preferably 8%.
It is at least 0%, more preferably at least 90%, particularly preferably at least 95%. If the ratio is less than 80%, the hollow fiber membrane may be broken during use after treatment with a renaline solution, which is not preferable. Further, the hollow fiber type selective separation membrane of the present invention preferably has a breaking elongation of 50% or more, particularly 70% or more.

Furthermore, in the hollow fiber type selective separation membrane of the present invention, the water permeation rate before the treatment with the renalin solution is reduced.
The ratio of the water permeation rate after the treatment with the renaline solution is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more. If the ratio is less than 80%, the dirt and clogging of the hollow fiber membrane are not eliminated, and the original separation function is not exhibited, which is not preferable. Further, the hollow fiber type selective separation membrane of the present invention has a capacity of 15 ml / m ² · hr · mm
It is preferable to have a water permeability of Hg or more. The water permeation rate is 150 pure water in a bundle of 120 mini modules.
It measures the water permeation rate when permeating the hollow fiber membrane while maintaining a pressure of mmHg.

In the production of the hollow fiber type selective separation membrane of the present invention,
A dry-wet spinning method, which is a spinning film forming method generally known from the past, is adopted. Specifically, for example, the film is produced by the following method.

First, a spinning dope containing a hydrophobic polymer, a hydrophilic polymer and a solvent is prepared. As the solvent used herein, a solvent capable of dissolving both a hydrophobic polymer and a hydrophilic polymer is used, and is not particularly limited. For example, N-methyl-2-pyrrolidone, dimethyl sulfoxide, N-dimethylacetamide or the like can be used. Of course, these solvents can be used alone, but a plurality of solvents can be mixed and used to adjust the solubility. These solvents are preferably contained at 35 to 75% by weight in the spinning dope.

Further, a solvent which does not show solubility in the hydrophobic polymer and the hydrophilic polymer is mixed with the solvent as a non-solvent,
Solubility can also be adjusted. Examples of such non-solvents include polyhydric alcohols such as monoethylene glycol, triethylene glycol, polyethylene glycol, and glycerin, and lower alkyl ether derivatives thereof, and these may be used alone or in combination of two or more. Can be used. These non-solvents are preferably blended in an amount of 7 to 35% by weight in the spinning dope.

The hydrophilic polymer contained in the spinning solution is:
After the film is formed, it remains in the hollow fiber membrane. Although the residual ratio varies depending on the molecular weight, type, and the like, it is preferable that the spinning dope contains a hydrophilic polymer in an amount of 0.5 to 10% by weight. Since the higher the molecular weight is, the higher the ratio of remaining in the hollow fiber membrane is, it is preferable to use those having a polymerization average molecular weight in the range of 45,000 to 11,000,000.

For example, when polyvinylpyrrolidone having a polymerization average molecular weight of 45,000 to 11,000,000 is used as the hydrophilic polymer, the spinning solution contains 0.5 to 10.0% by weight, particularly 1.5 to 3.5% by weight. Preferably. The higher the molecular weight of the hydrophilic polymer, the more likely it is to remain in the hollow fiber membrane. Therefore, when the molecular weight of polyvinylpyrrolidone is even higher, the content in the spinning dope may be lower than the above.

This spinning dope preferably has a viscosity at 140 ° C. of 100 to 500 poise, particularly preferably 120 to 400 poise. When the viscosity of the spinning dope is less than 100 poise, the speed of the coagulation liquid entering the spinning dope increases, and the gelation rate increases. As a result, the membrane structure of the hollow fiber type selective separation membrane becomes an asymmetric structure. turn into. Conversely, when the viscosity exceeds 500 poise, it becomes difficult to discharge the spinning solution from the spinneret.
By adjusting the viscosity of the spinning solution to such a range, it is possible to stably discharge the spinning solution, suppress the invasion speed of the coagulation solution, suppress the gelation speed, and achieve a uniform film structure.

Next, the spinning solution is discharged from a spinneret (for example, a tube-in-orifice type spinneret) into a gaseous atmosphere and travels 1 mm to 100 mm, and at the same time, a hollow forming aid is discharged from the center of the spinneret. After forming the part, it is led to a coagulation bath for coagulation.

The gas atmosphere from which the spinning dope is discharged is not particularly limited, and specific examples include air, nitrogen, oxygen, carbon dioxide, argon, and helium, but usually air.

The hollow forming aid discharged from the inside of the spinneret is not particularly limited. Specifically, air, nitrogen, oxygen, carbon dioxide, argon, helium, etc., or a mixture of two or more thereof are used. Examples include a gas such as a gas, and a liquid that is incompatible with the above mixed solvent such as liquid paraffin and isopropyl myristate.

The coagulation bath is composed of a liquid that is compatible with the solvent of the spinning dope and is incompatible with the hydrophobic polymer and the hydrophilic polymer. May be contained. In addition, usually, the solvent used for the spinning solution (for example, N-methyl-2-pyrrolidone),
The used non-solvent (for example, polyethylene glycol) and the like are contained.

After the introduction into the coagulation bath, the hollow fiber membrane is introduced into a washing bath, where the mixed solvent and the non-solvent are washed away.
Next, a membrane pore holding process is performed, and the film is dried. This pore holding treatment serves to prevent the pores from shrinking and crushing due to drying or standing. If drying is performed without performing such a treatment, the uniform membrane structure is not retained because the pores shrink significantly due to drying.

The membrane pore retaining treatment is performed by immersing the membrane pore retaining agent, for example, in an aqueous solution of glycerin (for example, concentrated glycerin manufactured by NOF Corporation), polyethylene glycol, polypropylene glycol or the like, and then drying it sufficiently.
By such a treatment, only the pore retaining agent remains in the pores.

The concentration of the pore retaining agent in the aqueous solution containing the pore retaining agent is preferably 45 to 65% by weight, particularly preferably 50 to 60% by weight. If the concentration is too low, the shrinkage of the pores in drying becomes too large and does not show an effect as a pore retaining agent,
On the other hand, if the concentration is too high, the viscosity of the aqueous solution containing the pore-holding agent increases, and the solution does not enter the pores well.

The hollow fiber membrane obtained by such a production method is bundled into a plurality of, for example, 8000 to 12,000, and modularized, and is used for ultrafiltration, dialysis, and diafiltration, and particularly for blood purification. Will be useful.

[0038]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. In Examples and Comparative Examples, “parts” means “parts by weight”. Example 1 25 parts of polyethersulfone (polyethersulfone VICTREX, manufactured by Sumitomo Chemical Co., Ltd.) having a reduced viscosity of 0.7 in a 1% by weight dimethylformamide solution, polyvinylpyrrolidone (manufactured by BASF, Povidone K-90, polymerization) Average molecular weight 1100000) 3 parts, N-methyl-2-pyrrolidone (Mitsubishi Chemical) 43 parts, polyethylene glycol (Daiichi Kogyo Seiyaku, PEG200, molecular weight 200) 29
The mixture was uniformly dissolved to prepare a spinning dope. This spinning solution is 14
It had a viscosity of 136 poise at 0 ° C. (measured using a B-type viscometer (B8H-HH type, manufactured by Tokyo Keiki)). The spinning solution was discharged from the sheath using a tube-in-orifice type spinneret heated to 140 ° C., and simultaneously, nitrogen gas was discharged to the core to form a hollow portion. The discharged spinning dope was applied to a 30 ° C. coagulation bath (24 parts of N-methyl-2-pyrrolidone, molecular weight 2) provided 5 mm below the spinneret.
Of water and a 50% glycerin aqueous solution at 50 ° C., and then dried at 80 ° C. to 75 m / m.
Wound at a speed of minutes.

The obtained hollow fiber type selective separation membrane has an inner diameter of 20.
0.3 μm and an outer diameter of 258.1 μm. When a SEM photograph (× 1000) of a cross section of the hollow fiber type selective separation membrane was taken, it had a uniform structure as shown in FIG. Using this hollow fiber type selective separation membrane, a module having an effective membrane area of 1.51 m ² was prepared, and the water permeability, the sieving coefficient of β ₂ -MG, and the elongation at break were evaluated by the following methods. Table 1 shows the results.

Measurement method 1. Measurement of Elongation at Break of Hollow Fiber Membrane The tensile elongation was measured using Tensilon UTMII manufactured by Toyo Baldwin at a tensile speed of 100 mm / min and a distance between chucks of 100 mm. 2. Measurement of the sieving coefficient of β ₂ -microglobulin The sieving coefficient SC is represented by the following equation. SC = (2 × filtrate concentration) / (inlet concentration + outlet concentration) As a measurement stock solution, 0.01 wt% β ₂ -microglobulin-phosphate buffer (pH 7.2) was used. The concentration of the undiluted solution at the inlet, the concentration of the undiluted solution at the outlet, and the concentration of the filtrate were measured, and the sieving coefficient SC was calculated (module temperature 37 ° C., filtration flow rate 2
0 ml / min). 3. Measurement of water permeation rate 120 units of mini-modules were thoroughly washed with pure water, and 37
° C is passed through the hollow fiber membrane while maintaining a pressure of 150 mmHg, and the water permeation rate (UFR ml / m ²
.Hr.mmHg).

After the module was subjected to a regeneration treatment with the following renaline solution, the water permeability, the sieving coefficient of β ₂ -MG and the elongation at break were evaluated. Table 1 shows the results.

<Regeneration treatment step with renalin solution> 1) The outside of the hollow fiber membrane is washed with 250 ml of sterile water. 2) The inside of the hollow fiber membrane is washed with sterile water at a flow rate of 6 liter / min for 20 seconds. 3) Backwash with renaline solution diluted to 2% for 35 seconds. 4) Rinse the inside of the hollow fiber membrane with a 2% diluted renaline solution. 5) The hollow fiber membrane is filled with a 2% diluted renaline solution for 120 seconds. 6) Rinse the outside of the hollow fiber membrane with sterile water at a flow rate of 1 liter / min for 15 seconds. 7) The inside of the hollow fiber membrane is rinsed with sterile water at a flow rate of 6 L / min for 30 seconds. 8) The inside of the hollow fiber membrane is rinsed with sterile water at a flow rate of 1 liter / min for 40 seconds. 9) Drain sterile water. 10) Rinse the outside of the hollow fiber membrane with sterile water at a flow rate of 1 liter / min for 15 seconds. 11) Rinse the inside of the hollow fiber membrane with sterile water at a flow rate of 6 L / min for 6 seconds. 12) Renalin solution 7 with the outside of the hollow fiber membrane diluted to 3.25%
Rinse with 00 ml. 13) Renalin solution 7 with the inside of the hollow fiber membrane diluted to 3.25%
Rinse with 00 ml.

Example 2 In Example 1, a polyether sulfone having a reduced viscosity of 0.7 in a 1% by weight dimethylformamide solution (polyethersulfone VICTREX, manufactured by Sumitomo Chemical Co., Ltd.)
24 parts, polyvinylpyrrolidone (manufactured by BASF, povidone K-90, polymerization average molecular weight 1100000) 3 parts, N
-Methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical) 44 parts, polyethylene glycol (manufactured by Daiichi Kogyo Seiyaku, PEG200,
(Molecular weight 200) 29 parts were uniformly dissolved, and the spinning stock solution (14
Except that the viscosity at 0 ° C. was 103 poise).
A hollow fiber type selective separation membrane was obtained in the same manner as in Example 1.

The obtained hollow fiber type selective separation membrane has an inner diameter of 20.
The outer diameter was 0.1 μm and the outer diameter was 258.3 μm. When a SEM photograph (× 1000) of the cross section of the hollow fiber type selective separation membrane was taken, it had a uniform structure as shown in FIG. A module similar to that of Example 1 was prepared using this hollow fiber type selective separation membrane, and the water permeability, the sieving coefficient of β ₂ -MG, and the elongation at break were evaluated. Table 1 shows the results.

After subjecting this module to the same regeneration treatment as in Example 1, the module was again evaluated for water permeability, β ₂ -MG sieving coefficient and elongation at break. Table 1 shows the results.

Comparative Example 1 In Example 1, polyether sulfone having a reduced viscosity of 0.7 in a 1% by weight dimethylformamide solution (polyether sulfone VICTREX, manufactured by Sumitomo Chemical Co., Ltd.)
20 parts, polyvinylpyrrolidone (manufactured by BASF, povidone K-90, polymerization average molecular weight 1100000) 3 parts, N
-Methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation) 46 parts, polyethylene glycol (manufactured by Daiichi Kogyo Seiyaku, PEG200,
(Molecular weight 200) 31 parts were uniformly dissolved in the spinning solution (1).
Except that the viscosity at 40 ° C. was 43 poise).
A hollow fiber type selective separation membrane was obtained in the same manner as in Example 1.

The obtained hollow fiber type selective separation membrane has an inner diameter of 19
The diameter was 9.5 μm and the outer diameter was 265.6 μm. When a SEM photograph (× 1000) of the cross section of the hollow fiber type selective separation membrane was taken, it had an asymmetric structure as shown in FIG. A module similar to that of Example 1 was prepared using this hollow fiber type selective separation membrane, and the water permeability, the sieving coefficient of β ₂ -MG, and the elongation at break were evaluated. Table 1 shows the results.

After subjecting this module to the same regeneration treatment as in Example 1, the module was again evaluated for water permeability, β ₂ -MG sieving coefficient and elongation at break. Table 1 shows the results.

[0049]

[Table 1]

As shown in Table 1, in the hollow fiber type selective separation membranes obtained in Examples 1 and 2, β ₂ -MG, water permeability and elongation at break were all before and after the regeneration treatment with the renaline solution. The ratio was 97% or more, and the performance was hardly changed. However, in the hollow fiber type selective separation membrane obtained in Comparative Example 1, the elongation at break was about 80% after the treatment before the regeneration treatment with the renaline solution, but the β ₂ -MG and the water permeability In each case, the ratio after the treatment with respect to the regeneration treatment with the renaline solution was less than 80%, and the performance was clearly reduced.

[0051]

As is apparent from the above description, according to the present invention, a hydrophobic polymer having chemical resistance and physical strength, a hydrophilic polymer which improves the separation performance of a membrane and a stain during use can be obtained. It has high chemical resistance and physical strength due to the use of molecules and a uniform film structure, and the hydrophilic polymer flows out of the film even after chemical treatment for reprocessing or backwashing. And a hollow fiber membrane whose separation performance does not decrease can be provided.

[Brief description of the drawings]

FIG. 1 is an SEM photograph (showing the shape of a thin film) of a cross section of a hollow fiber type selective separation membrane obtained in Example 1.

FIG. 2 is an SEM photograph (showing the shape of a thin film) of a cross section of a hollow fiber type selective separation membrane obtained in Example 2.

FIG. 3 is an SEM photograph (showing the shape of a thin film) of a cross section of the hollow fiber type selective separation membrane obtained in Comparative Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI D06M 13/00 D06M 13/00

Claims (10)

[Claims] 1. A hollow fiber type selective separation membrane containing a hydrophobic polymer and a hydrophilic polymer, which has a uniform membrane structure and has a sieving coefficient of β ₂ -microglobulin before treatment with a renalin solution. A hollow fiber type selective separation membrane, wherein the ratio of the sieving coefficient of β ₂ -microglobulin after treatment with a renaline solution is 80% or more. 2. The ratio of the elongation at break after treatment with a renalin solution to the elongation at break before treatment with a renalin solution is 80%.
The hollow fiber type selective separation membrane according to claim 1, wherein: 3. The ratio of the water permeation rate after the treatment with the renalin solution to the water permeation rate before the treatment with the renalin solution is 80%.
The hollow fiber type selective separation membrane according to claim 1, wherein: 4. The hollow fiber type selective separation membrane according to claim 1, wherein the hydrophobic polymer is a polysulfone-based polymer or a polyethersulfone-based polymer. 5. The hollow fiber type selective separation membrane according to claim 1, wherein the hydrophilic polymer is polyvinylpyrrolidone. 6. The polymerization average molecular weight of the hydrophilic polymer is 450.
2. The structure according to claim 1, wherein the number is from 00 to 1100000.
6. The hollow fiber type selective separation membrane according to any one of items 5 to 5. 7. A hollow fiber type selective separation membrane in which a spinning solution containing a hydrophobic polymer, a hydrophilic polymer and a solvent is discharged in a gaseous atmosphere so as to form a hollow shape, and then guided to a coagulation bath for coagulation. The spinning dope 140
A method for producing a hollow fiber type selective separation membrane, wherein the viscosity at 100C is 100 to 500 poise. 8. A spinning dope having a viscosity at 140 ° C. of 12
The method for producing a hollow fiber type selective separation membrane according to claim 7, wherein the pressure is 0 to 400 poise. 9. The method according to claim 9, wherein the hydrophilic polymer is contained in the spinning solution at a concentration of 0.5 to 1
The method for producing a hollow fiber type selective separation membrane according to claim 7, wherein the content is 0% by weight. 10. The hydrophilic polymer has a polymerization average molecular weight of 450.
It is a polyvinylpyrrolidone of 00-1100000,
And polyvinylpyrrolidone is 0.5 to 10% in the spinning solution.
The method for producing a hollow fiber type selective separation membrane according to claim 7, characterized in that the content is contained by weight%.