Method for producing hollow fiber exchange membrane and hollow fiber exchange membrane

Abstract

The application discloses a preparation method of a hollow fiber exchange membrane and the hollow fiber exchange membrane, and the preparation method comprises the following steps: stirring and melting poly(4-methyl-1-pentene), a diluent, an antioxidant and an anti-volatilization agent at 220 DEG C to 280 DEG C to obtain a casting solution; extruding and spinning the casting solution through a spinneret to form a hollow fiber, then passing through an air gap to enter a cooling liquid to solidify to obtain a semi-finished product membrane; placing the semi-finished product membrane into an extracting agent to remove the diluent in the semi-finished product membrane through extraction; and drying the semi-finished product membrane after the diluent is removed to obtain the hollow fiber exchange membrane. The preparation method of the hollow fiber exchange membrane adds the antioxidant and the anti-volatilization agent into the diluent, solves the problems of discoloration and decomposition of the diluent caused by high temperature during high-temperature mixing and extrusion molding of the casting solution, the size, gas flux and mechanical properties of the prepared membrane are more stable, and the prepared hollow fiber exchange membrane has a better membrane structure and better performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of membrane technology, in particular to a preparation method of a hollow fiber exchange membrane and the hollow fiber exchange membrane. BACKGROUND

[0002] Extracorporeal Membrane Oxygenation (ECMO) system has the function of replacing the human lung to regulate the oxygen and carbon dioxide content in the blood, and has become an important medical device in the treatment of acute respiratory diseases, waiting for lung transplantation stage and cardiovascular surgery process. The provision of ECMO also reflects the emergency level of a country. However, China's ECMO equipment is heavily dependent on imports, and as an emergency medical device, domestic production is necessary, and domestic products are needed in emergency and emergency situations.

[0003] Hollow fiber exchange membrane (also known as artificial lung membrane) is the core component of ECMO system, and its function is to exchange CO2 in patient's blood and O2 in air, which is also the core step of human respiration. Due to its good oxygen flux and nitrogen-oxygen selectivity, low dissolution and biological safety, excellent mechanical and thermal stability, and excellent air permeability, poly-4-methyl-1-pentene (PMP) hollow fiber exchange membrane has become the main direction of artificial lung research in recent years.

[0004] At present, the preparation of PMP hollow fiber exchange membrane usually adopts thermal induced phase separation method (TIPS), through the regulation of casting solution formula, including the composition of diluent, polymer concentration and molecular weight, special additives, etc. The diversity and controllability of membrane structure can be realized, and isotropic, uniform pore size and high porosity PMP hollow fiber exchange membrane can be obtained. However, the high melting point of PMP requires a higher temperature in the process of film processing. The problems of oxidation discoloration and decomposition of diluent under high temperature conditions will lead to poor membrane structure and affect the performance of the prepared PMP hollow fiber exchange membrane. SUMMARY

[0005] Therefore, it is necessary to provide a preparation method of a hollow fiber exchange membrane which can solve the above problems.

[0006] In addition, it is also necessary to provide a hollow fiber exchange membrane prepared by the above preparation method of a hollow fiber exchange membrane.

[0007] A preparation method of a hollow fiber exchange membrane, comprising the following steps:

[0008] poly(4-methyl-1-pentene), diluent, antioxidant and anti-volatile agent are stirred and melted at 220℃-280℃ to obtain a casting solution;

[0009] extruding the casting solution through a spinneret to form a hollow fiber shape, and then passing through an air gap into a cooling liquid to solidify to obtain a semi-finished membrane;

[0010] immersing the semi-finished membrane into an extractant to remove the diluent from the semi-finished membrane; and

[0011] drying the semi-finished membrane from which the diluent has been removed to obtain the desired hollow fiber exchange membrane.

[0012] In one embodiment, the concentration of the poly(4-methyl-1-pentene) in the casting solution is 20 wt% to 60 wt%, the concentration of the diluent is 40 wt% to 80 wt%, the concentration of the anti-volatilization agent is 0.1 wt% to 5 wt%, and the concentration of the antioxidant is 0.1 wt% to 5 wt%.

[0013] In one embodiment, the antioxidant is at least one selected from the group consisting of tris(2,4-di-tert-butylphenyl) phosphite, 2,6-di-tert-butyl-p-cresol, pentaerythritol tetrakis(3-laurylthiopropionate), β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-octadecyl ester, and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine.

[0014] In one embodiment, the diluent is at least one selected from the group consisting of dibutyl phthalate, di-n-octyl phthalate, di(2-ethylhexyl) phthalate, dibutyl terephthalate, and diphenyl phthalate.

[0015] The anti-volatilization agent is at least one selected from the group consisting of epoxidized soybean oil, octyl trimellitate, nonyl trimellitate, tridecyl trimellitate, a polyester plasticizer, and an epoxy resin.

[0016] In one embodiment, in the operation of extruding the casting solution through a spinneret to form a hollow fiber shape, and then passing through an air gap into a cooling liquid to solidify to obtain a semi-finished membrane, the difference between the outer diameter of the spinneret and the inner diameter of the spinneret is 5 μm to 500 μm.

[0017] In one embodiment, the inner diameter of the spinneret is 50 μm to 500 μm, the outer diameter of the spinneret is 100 μm to 1000 μm, the air gap is 10 mm to 500 mm, and the spinning speed is 20 m / min to 200 m / min.

[0018] In one embodiment, the cooling liquid is a mixture of deionized water and ethylene glycol at a volume ratio of 0.5 to 2:1, and the temperature of the cooling liquid is -10°C to 80°C.

[0019] In one embodiment, in the operation of extracting the diluent in the semi-finished film, the extractant is selected from at least one of ethanol, isopropyl alcohol, N, N-dimethylformamide, ethyl acetate, amyl acetate, dichloromethane and ethylene glycol butyl ether, and the extraction time is 10h-100h.

[0020] In one embodiment, in the operation of drying the semi-finished film after the diluent is removed, the drying temperature is 40℃-200℃, and the drying time is 10h-50h.

[0021] A hollow fiber exchange membrane is prepared by the method for preparing a hollow fiber exchange membrane.

[0022] The method for preparing a hollow fiber exchange membrane of the present application first uniformly mixes poly(4-methyl-1-pentene), a diluent, an antioxidant and an anti-volatilization agent at high temperature, forms by one-time extrusion, enters a cooling liquid after an air section to cause thermal induced phase separation, and finally extracts the diluent to obtain a hollow fiber exchange membrane. The method for preparing a hollow fiber exchange membrane of the present application can reduce degradation of the casting solution and volatilization of the diluent by adding an antioxidant and an anti-volatilization agent in the diluent, solves the problems of oxidation discoloration and decomposition of the diluent caused by high temperature during high-temperature mixing and extrusion of the casting solution, and makes the size, gas flux and mechanical properties of the prepared membrane more stable, and the membrane structure and performance of the prepared hollow fiber exchange membrane better.

[0023] In addition, the addition of the antioxidant and the anti-volatilization agent also effectively alleviates the problems of large spinning smoke and pungent smell caused by high-temperature degradation of the casting solution during TIPS spinning, and the spinning process is more green and environmentally friendly.

[0024] The hollow fiber exchange membrane prepared by the method for preparing a hollow fiber exchange membrane of the present application has a thin dense skin on the surface, has high gas permeation performance, can realize rapid exchange of gas, and can be applied in an artificial lung.

[0025] The method for preparing a hollow fiber exchange membrane of the present application optimizes and adjusts the process parameters of the whole spinning on a pilot scale, cooperates with optimization of the casting solution and optimization of the equipment process, realizes large-batch continuous spinning of the hollow fiber exchange membrane, and has potential for practical industrial application. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] wherein:

[0028] Figure 1 Flow chart of the method for preparing the hollow fiber exchange membrane according to an embodiment.

[0029] Figure 2 Principle diagram of the method for preparing the hollow fiber exchange membrane according to an embodiment. Figure 1

[0030] Figure 3a Photo of the hollow fiber exchange membrane prepared according to Example 1.

[0031] Figure 3b Photo of the hollow fiber exchange membrane prepared according to Comparative Example 1.

[0032] Figure 4a SEM photo of the brittle fracture section of the membrane filament of the hollow fiber exchange membrane prepared according to Example 1.

[0033] Figure 4b SEM photo of the dense sheath layer of the membrane filament of the hollow fiber exchange membrane prepared according to Example 1.

[0034] Figure 4c SEM photo of the surface of the membrane filament of the hollow fiber exchange membrane prepared according to Example 1.

[0035] Figure 4d SEM photo of the dense porous structure of the membrane filament of the hollow fiber exchange membrane prepared according to Example 1.

[0036] Figure 5a SEM photo of the brittle fracture section of the membrane filament of the hollow fiber exchange membrane prepared according to Comparative Example 1.

[0037] Figure 5b SEM photo of the dense sheath layer of the membrane filament of the hollow fiber exchange membrane prepared according to Comparative Example 1.

[0038] Figure 5c SEM photo of the surface of the membrane filament of the hollow fiber exchange membrane prepared according to Comparative Example 1.

[0039] Figure 5d SEM photo of the dense porous structure of the membrane filament of the hollow fiber exchange membrane prepared according to Comparative Example 1. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work, fall within the protection scope of the present application.

[0041] ​The application discloses a preparation method of a hollow fiber exchange membrane.

[0042] S10, stirring and melting poly(4-methyl-1-pentene), a diluent, an antioxidant and an anti-volatilization agent at 220-280 DEG C to obtain a casting solution.

[0043] Preferably, in the casting solution, the concentration of poly(4-methyl-1-pentene) is 20wt-60wt%, the concentration of the diluent is 40wt%-80wt%, the concentration of the anti-volatilization agent is 0.1wt%-5wt%, and the concentration of the antioxidant is 0.1wt%-5wt%.

[0044] Preferably, in S10, the antioxidant is at least one selected from the group consisting of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), 2,6-di-tert-butyl-p-cresol (antioxidant BHT), pentaerythritol tetrakis(3-laurylthiopropionate) (antioxidant 412s), n-octadecyl beta-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076) and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (antioxidant 1098).

[0045] Preferably, in S10, the diluent is at least one selected from the group consisting of dibutyl phthalate (DBP), di-n-octyl phthalate (DOP), di(2-ethylhexyl) phthalate (DEHP), dibutyl terephthalate (DOTP) and diphenyl phthalate (DPE).

[0046] Preferably, in S10, the anti-volatilization agent is at least one selected from the group consisting of epoxy soybean oil, octyl trimellitate (TOTM), nonyl trimellitate (TINTM), tridecyl trimellitate (TDTM), polyester plasticizer (UN630) and epoxy resin (E-44).

[0047] The addition of the antioxidant and the anti-volatilization agent can reduce the degradation of the casting solution and the volatilization of the diluent, the prepared membrane filament size, gas flux and mechanical properties are more stable, the problem of large spinning smoke and pungent smell caused by high-temperature degradation of the casting solution in the TIPS spinning process can be effectively alleviated, and the spinning process is more green and environmentally friendly.

[0048] S20, extruding and spinning the casting solution through a spinneret to form a hollow fiber, and then passing through an air gap to enter a cooling liquid to solidify to obtain a semi-finished product membrane.

[0049] Preferably, in S20, the difference between the outer diameter of the spinneret and the inner diameter of the spinneret is 5-500 mu m.

[0050] Specifically, in S20, the inner diameter of the spinneret is 50-500 microns, the outer diameter of the spinneret is 100-1000 microns, the air gap is 10-500 mm, and the spinning speed is 20-200 m / min.

[0051] By optimizing and adjusting the overall spinning process parameters on a pilot scale, and coordinating the casting solution optimization and equipment process optimization, mass production of hollow fiber exchange membranes is realized, and the potential for practical industrial application is achieved.

[0052] Preferably, in S20, the cooling liquid is a mixture of deionized water and ethylene glycol in a volume ratio of 0.5-2:1, and the temperature of the cooling liquid is -10-80 DEG C.

[0053] In S20, before the casting solution is extruded through the spinneret, the casting solution is also subjected to a defoaming operation.

[0054] Generally, the defoaming can be static defoaming (room temperature, static 12 h) or micro-vacuum defoaming (50-100 kPa, room temperature, 4 h).

[0055] In S30, the semi-finished membrane is placed in an extractant to remove the diluent in the semi-finished membrane.

[0056] Preferably, in S30, the extractant is selected from at least one of ethanol, isopropyl alcohol, N, N-dimethylformamide, ethyl acetate, amyl acetate, dichloromethane and ethylene glycol butyl ether, and the extraction time is 10-100 h.

[0057] In S40, the semi-finished membrane from which the diluent has been removed is dried to obtain the desired hollow fiber exchange membrane.

[0058] Preferably, in S40, in the operation of drying the semi-finished membrane from which the diluent has been removed, the drying temperature is 40-200 DEG C, and the drying time is 10-50 h.

[0059] The preparation method of the hollow fiber exchange membrane of the present application first uniformly mixes poly(4-methyl-1-pentene), a diluent, an antioxidant and an anti-volatile agent at high temperature, forms a one-time molding by extrusion, enters a cooling liquid after the air section to cause thermal-induced phase separation, and finally extracts the diluent to obtain the hollow fiber exchange membrane. The preparation method of the hollow fiber exchange membrane of the present application can reduce the degradation of the casting solution and the volatilization of the diluent by adding an antioxidant and an anti-volatile agent to the diluent, solve the problems of oxidation discoloration and decomposition of the diluent caused by high temperature during high-temperature mixing and extrusion molding of the casting solution, and make the prepared membrane size, gas flux and mechanical properties more stable, and the hollow fiber exchange membrane has better membrane structure and performance.

[0060] In addition, the addition of the antioxidant and the anti-volatilization agent also effectively alleviates the problem of large spinning smoke and pungent smell caused by high-temperature degradation of the casting solution in the TIPS spinning process, and the spinning process is more green and environmentally friendly.

[0061] The preparation method of the hollow fiber exchange membrane of the application has a thin dense skin layer on the surface of the hollow fiber exchange membrane, and has high gas permeability, so that rapid gas exchange can be realized, and application in an artificial lung can be realized.

[0062] The preparation method of the hollow fiber exchange membrane of the application optimizes and adjusts the process parameters of the overall spinning on a pilot scale, cooperates with the optimization of the casting solution and the optimization of the equipment process, realizes the mass production of the hollow fiber exchange membrane, and has the potential for practical industrial application.

[0063] The application also discloses the hollow fiber exchange membrane prepared by the preparation method of the hollow fiber exchange membrane.

[0064] The following is a specific example. In the example, poly(4-methyl-1-pentene), di-n-octyl phthalate (DOP), 2,6-di-tert-butyl-p-cresol (antioxidant BHT), and epoxy soybean oil are all medical-grade products purchased from Shanghai Aldrin Reagent.

[0065] Example 1

[0066] Reference Figure 2 As shown in the figure, the example adopts a TIPS method to industrially and continuously prepare a PMP hollow fiber exchange membrane for ECMO.

[0067] 100g of poly(4-methyl-1-pentene), 233.33g of di-n-octyl phthalate (DOP), 1g of 2,6-di-tert-butyl-p-cresol (antioxidant BHT), and 3g of epoxy soybean oil are mixed and stirred to be molten to obtain a uniform casting solution.

[0068] After the casting solution is deaerated in a micro-vacuum, the casting solution is fed into a double-screw extruder, and the casting solution is extruded into a hollow fiber shape through a spinneret (inner diameter: 200μm, outer diameter: 400μm) at 225℃ after being fed, and then passes through an air gap into a cooling liquid at 5℃ to be solidified and formed, and finally the PMP hollow fiber exchange membrane is obtained by washing, extracting, drying, and collecting the yarn. The air gap is 70mm, the cooling liquid is a mixture of deionized water and ethylene glycol in a volume ratio of 1:1, the spinning speed is 50m / min, the residence time in the cooling liquid is 3s, the extracting agent is ethanol, the extraction time is 50h, and the drying temperature is 120℃.

[0069] Comparative Example 1

[0070] 100 g of poly(4-methyl-1-pentene) and 233.33 g of di-n-octyl phthalate (DOP) were mixed at 250°C, and a uniform casting solution was obtained by stirring and melting.

[0071] After the casting solution was defoamed under micro-vacuum, it was fed into a twin-screw extruder. After the casting solution was fed, it was extruded into a hollow fiber shape through a spinneret (inner diameter: 200 μm, outer diameter: 400 μm) at 225°C, and then passed through an air gap into a cooling liquid at 5°C to solidify and form. Finally, the PMP hollow fiber exchange membrane was obtained by washing, extracting, and drying. The air gap was 70 mm, the cooling liquid was a mixture of deionized water and ethylene glycol at a volume ratio of 1:1, the spinning speed was 50 m / min, the residence time in the cooling liquid was 3 s, the extracting agent was ethanol, the extraction time was 50 h, and the drying temperature was 120°C.

[0072] Test Example 1

[0073] The PMP hollow fiber exchange membranes obtained in Example 1 and Comparative Example 1 were photographed, respectively, to obtain Figure 3a and Figure 3b .

[0074] In combination with Figure 3a and Figure 3b , it can be seen that the PMP hollow fiber exchange membrane obtained in Example 1 has a smooth and white surface without granular protrusions, and the PMP hollow fiber exchange membrane obtained in Comparative Example 1 has a rough and yellow surface and granular protrusions.

[0075] The preparation method of the PMP hollow fiber exchange membrane of Example 1 has been tested in actual production on a pilot scale or larger, and the PMP hollow fiber exchange membrane obtained in Example 1 has no yellowing phenomenon caused by oxidation and has potential for industrial application.

[0076] Test Example 2

[0077] The PMP hollow fiber exchange membranes obtained in Example 1 and Comparative Example 1 were microscopically observed, respectively, to observe the appearance morphology of the brittle fracture surface of the membrane and the morphology of the dense skin layer of the membrane, respectively, to obtain Figure 4a , Figure 4b , Figure 4c , Figure 4d , Figure 5a , Figure 5b , Figure 5c and Figure 5d .

[0078] In combination with Figure 4a , Figure 4b , Figure 4c , Figure 4d , Figure 5a , Figure 5b , Figure 5cand Figure 5d It can be seen that the microstructure of the PMP hollow fiber exchange membrane prepared in Example 1 is stable, has a dense surface layer and a sponge-like pore support layer structure, and the macropore defects are reduced; while the surface of the PMP hollow fiber exchange membrane prepared in Comparative Example 1 has obvious defects

[0079] Therefore, the results of continuous spinning production and microstructure characterization prove that the addition of 2,6-di-tert-butyl-p-cresol (antioxidant BHT) and epoxy soybean oil in the formula can effectively improve the controllability of the structure of the PMP hollow fiber exchange membrane.

[0080] Test Example 3

[0081] The gas permeability test was performed on the PMP hollow fiber exchange membranes prepared in Example 1 and Comparative Example, respectively, and the results are shown in Table 1.

[0082] Table 1: Gas permeability test results

[0083]

[0084] In combination with Table 1, it can be seen that the N2 flux test shows that the PMP hollow fiber exchange membrane prepared in Example 1 has a larger gas flux and excellent test stability (STD); while the PMP hollow fiber exchange membrane prepared in Comparative Example 1 has a large gas flux, but poor test stability, which is caused by the formation of internal non-uniform macropore defects. In addition, the CO2 / O2 gas selectivity of the PMP hollow fiber exchange membrane prepared in Example 1 is obviously higher than that of the PMP hollow fiber exchange membrane prepared in Comparative Example 1, which further illustrates that the membrane filament prepared by adding antioxidants and anti-volatilization agents has a denser skin layer and fewer macropore defects.

[0085] Test Example 4

[0086] The mechanical strength test was performed on the PMP hollow fiber exchange membranes prepared in Example 1 and Comparative Example, respectively, and the results are shown in Table 2.

[0087] Table 2: Mechanical strength test results

[0088]

[0089]

[0090] The mechanical properties of the PMP hollow fiber exchange membrane have a significant influence on the subsequent weaving and packaging process of the hollow fiber exchange membrane filament. In order to prevent the deformation of the membrane filament during the weaving and packaging process, which leads to the decrease of gas flux and other phenomena, the hollow fiber exchange membrane filament is required to have certain mechanical properties.

[0091] In combination with Table 2, it can be seen that the mechanical strength of the PMP hollow fiber exchange membrane prepared in Example 1 is enhanced compared with the PMP hollow fiber exchange membrane prepared in Comparative Example 1, including that the breaking tensile strength, breaking elongation and elastic modulus thereof are all significantly improved.

[0092] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A method for producing a hollow fiber exchange membrane, characterized by, comprising the steps of: stirring and melting 20wt~60wt% of poly(4-methyl-1-pentene), 40wt%~80wt% of diluent, 0.1wt%~5wt% of antioxidant and 0.1wt%~5wt% of anti-volatilization agent at 220℃~280℃ to obtain a casting solution; extruding and spinning the casting solution through a spinneret to form hollow fibers, then passing through an air gap into a cooling liquid to solidify to obtain a semi-finished membrane; putting the semi-finished membrane into an extractant to remove the diluent in the semi-finished membrane by extraction; and drying the semi-finished membrane after the diluent is removed to obtain the required hollow fiber exchange membrane; wherein the antioxidant is selected from at least one of tris(2,4-di-tert-butylphenyl) phosphite, 2,6-di-tert-butyl-p-cresol, pentaerythritol tetrakis(3-laurylthiopropionate), β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-octadecyl ester and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine; and the anti-volatilization agent is selected from at least one of epoxidized soybean oil, octyl trimellitate, nonyl trimellitate, tridecyl trimellitate, polyester plasticizer and epoxy resin.

2. The method for producing a hollow fiber exchange membrane according to claim 1, characterized by, The diluent is selected from at least one of dibutyl phthalate, di-n-octyl phthalate, di(2-ethylhexyl) phthalate, dibutyl terephthalate and diphenyl ether phthalate.

3. The method for producing a hollow fiber exchange membrane according to any one of claims 1 to 2, characterized by, In the operation of extruding and spinning the casting solution through a spinneret to form hollow fibers, then passing through an air gap into a cooling liquid to solidify to obtain a semi-finished membrane, the difference between the outer diameter of the spinneret and the inner diameter of the spinneret is 5μm~500μm.

4. The method for producing a hollow fiber exchange membrane according to claim 3, characterized by, The inner diameter of the spinneret is 50μm~500μm, the outer diameter of the spinneret is 100μm~1000μm, the air gap is 10mm~500mm, and the spinning speed is 20m / min~200m / min.

5. The method for producing a hollow fiber exchange membrane according to claim 4, characterized by, The cooling liquid is a mixture of deionized water and ethylene glycol in a volume ratio of 0.5~2:1, and the temperature of the cooling liquid is -10℃~80℃.

6. The method for producing a hollow-fiber exchange membrane according to claim 1, characterized by, In the operation of removing the diluent in the semi-finished membrane by extraction, the extractant is selected from at least one of ethanol, isopropyl alcohol, N,N-dimethylformamide, ethyl acetate, amyl acetate, dichloromethane and ethylene glycol butyl ether, and the extraction time is 10h~100h.

7. The method for producing a hollow-fiber exchange membrane according to claim 1, characterized by, In the operation of drying the semi-finished membrane after the diluent is removed, the drying temperature is 40℃~200℃, and the drying time is 10h~50h.

8. A hollow fiber exchange membrane characterized by, The hollow fiber exchange membrane is prepared by the method of any one of claims 4~7.

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