JP2008188571A - Method of manufacturing hydrophilized aromatic ether based polymer membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a hydrophilized liquid treatment separation membrane using an aromatic ether based polymer having high hydrophobicity, high durability and high solvent resistance as a membrane raw material. <P>SOLUTION: The method of manufacturing the hydrophilized aromatic ether based polymer membrane uses a solution in which a hydrophilizing agent is dissolved as a coagulation liquid without adding the hydrophilizing agent in a membrane raw liquid in a wet membrane forming method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid comprising a hydrophilized aromatic ether polymer characterized by using a solution in which 0.001 wt% to 10 wt% of a hydrophilizing agent is used as a coagulating liquid in a wet film forming method. The present invention relates to a method for producing a treatment separation membrane.

  Conventionally, aromatic ether polymers have been widely used as gas separation membranes because of their high physical strength, solvent resistance, and water resistance that is manifested due to their high hydrophobicity, especially extremely good gas permeability. Has been studied.

  For example, when considering gas separation membranes in general with oxygen and nitrogen as separation objects, separation due to the difference in molecular size is difficult. As a result, as a study of an aromatic ether polymer membrane aiming at improving gas separation performance, after densifying the membrane surface pore diameter to 1.0 nm or less (see Non-Patent Document 1), how the membrane surface is dense The points of thinly manufacturing the layer (see Patent Document 1) and the point of adding an appropriate charged structure to the membrane surface to increase the gas permeation rate of the membrane material itself (see Patent Document 2) have been mainly implemented.

  From the viewpoint of the membrane production method and structure, a porous hollow fiber by a melt film-forming method using temperature-induced phase separation has been reported (see Non-Patent Document 2). The structure of the obtained hollow fiber is a uniform porous structure from the inner surface of the hollow fiber to the vicinity of the outer surface of the hollow fiber, and only the outermost surface is completely closed, so that gas separation by a very thin non-porous membrane on the outer surface is performed. Presumed to be the intended one.

  However, when considering a membrane used for a liquid treatment separation membrane which is an important use of the separation membrane along with the gas separation membrane, an aromatic ether polymer has not been used. The reason for this is that the aromatic polysulfone-based polymer as an excellent material already exists as a liquid separation membrane. In a liquid processing separation application in which a liquid processing separation membrane is provided, the general size of an object to be separated is 2.0 nm or more (see Non-Patent Document 1), and the separation function mainly used is size separation.

  Therefore, in order to size-separate a wide variety of separation objects in a liquid, it is necessary to form a porous membrane whose pore diameter is precisely controlled based on the size of the object. In this respect, aromatic polysulfone polymers have various good solvents that are miscible with water at around room temperature, and various membranes such as flat membranes and hollow fiber membranes can be formed using a wet film formation method. It is possible to manufacture. Also, it can be melt-molded as a resin, and various films can be produced using a melt film-forming method. That is, it is considered that the aromatic polysulfone-based polymer has a high degree of freedom in membrane processing and is a material that can freely produce a membrane having a necessary pore size.

  By the way, in general, when a separation membrane is used as a liquid treatment separation membrane for water, an aqueous solution, a water-soluble organic solvent such as alcohol, etc., the membrane is hydrophilized. Aromatic polysulfone-based polymers widely used as water treatment membranes and blood purification membranes are also formed by mixing hydrophilic polymers such as polyvinylpyrrolidone and polyethylene oxide as hydrophilizing agents at the stage of film formation. Thus, a polymer film made hydrophilic is manufactured.

On the other hand, the aromatic ether polymer did not have a good solvent miscible with water at around room temperature, and could not be processed into a film by a wet film forming method at around room temperature. As a result of the previous studies, the present inventors have found that a novel liquid treatment separation membrane having a high water permeability can be obtained by controlling the pore size by a wet film formation method using an aromatic ether polymer. (See Patent Document 3). However, when a film is formed by blending a hydrophilizing agent by a wet film forming method, the aromatic ether polymer has low solubility in a good solvent, so the concentration of the film substrate and the hydrophilizing agent can be adjusted freely. It was difficult. In some cases, the molecular weight and structure of the hydrophilizing agent are limited.
JP-A-3-65227 Japanese Patent Laid-Open No. 5-7745 PCT / JP2006 / 315902 Membrane technology (2nd edition), IPC, author: Marcel Mulder, supervision and translation: Masakazu Yoshikawa, Tsuyoshi Matsuura, Tsutomu Nakagawa (1997) P.16, 45-51, 256, 275-280 Polymer Vol. 36 No. 16, pp. 3085-3091, 1995: S. Bergmans, J. et al. Mewis, H.M. Bergmanns, H.M. Meijer

  An object of the present invention is to provide a method for producing a hydrophilized liquid treatment separation membrane characterized by using an aromatic ether polymer having high hydrophobicity, high durability, and high solvent resistance as a membrane raw material. It is to be.

The present inventors have intensively studied to solve the above-mentioned problems, and in a wet film forming method, using a solution in which a hydrophilizing agent is dissolved as a coagulating liquid, a hydrophilic ether polymer film that has been hydrophilized Has been found to be able to be produced, and the present invention has been completed.
That is, the present invention

（Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６は水素、炭素数１以上６以下を含む有機官能基、または、酸素、窒素または珪素を含有する炭素数６以下の非プロトン性有機官能基であり、それぞれ同一であっても、異なっても構わない。構造式中のｍは繰り返し単位数である。異なる繰り返し単位を２成分以上含む共重合体でも構わない。）
［２］数平均分子量が５，０００以上１，０００，０００以下の親水化剤を用いることを特徴とする上記１の製造方法。
［３］親水化剤として、ポリエチレングリコール、ポリビニルピロリドン、ポリアクリルアミド、および／またはそれらを親水性セグメントとして含有する共重合体を用いることを特徴とする上記１または２の製造方法。 [1] An aromatic ether-based polymer represented by the following formula (1) by a wet film-forming method, wherein a solution in which 0.001 to 10% by weight of a hydrophilizing agent is dissolved is used as the coagulation liquid. A method for producing a hydrophilized liquid treatment separation membrane comprising molecules.

(R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are hydrogen, an organic functional group containing 1 to 6 carbon atoms, or an aprotic having 6 or less carbon atoms containing oxygen, nitrogen or silicon. These organic functional groups may be the same or different, and m in the structural formula is the number of repeating units, and may be a copolymer containing two or more different repeating units.)
[2] The method according to 1 above, wherein a hydrophilizing agent having a number average molecular weight of 5,000 to 1,000,000 is used.
[3] The method according to 1 or 2 above, wherein as the hydrophilizing agent, polyethylene glycol, polyvinyl pyrrolidone, polyacrylamide, and / or a copolymer containing them as a hydrophilic segment are used.

  According to the present invention, it is possible to provide a method for producing a hydrophilic aromatic ether polymer film by using a solution in which a hydrophilizing agent is dissolved as a coagulating liquid in a wet film forming method. .

  The present invention will be specifically described.

  The liquid treatment separation membrane in the present invention is a porous membrane used for the purpose of separating a solid, liquid, or gas that is a separation target from a target mixed liquid that is to be separated at a temperature at which the separation processing is performed. It is. However, a membrane whose pore diameter is 1 nm or less and whose separation principle is not the size but the dissolution / diffusion of the separation object into the membrane is not included in the category of the liquid treatment separation membrane in the present invention. For example, reverse osmosis membranes intended for the removal and concentration of inorganic salts with atomic / ion sizes, pervaporation membranes for separating low molecular compounds with very close molecular sizes, etc. Not included in category.

式（１）で表されるＲ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６は水素、炭素数１以上６以下を含む有機官能基、または、酸素、窒素または珪素を含有する炭素数６以下の非プロトン性有機官能基であり、それぞれ同一であっても、異なっても構わない。構造式中のｍは繰り返し単位数である。式（１）に示す構造範囲内で異なる繰り返し単位を２成分以上含む共重合体でも構わない。本発明における芳香族エーテル系高分子の末端のフェノール性水酸基は分離対象物が液体中で安定して存在可能であるｐＨを維持するために、必要に応じてエステル化、エーテル化、エポキシ化など各種変性を実施することができる。また分離対象物の静電気的な特性との相性から、高分子末端にアミノ基、モノアルキルアミノ基、ジアルキルアミノ基、カルボキシル基、スルフォニル基などの化学構造を必要に応じて導入できる。 The aromatic ether polymer in the present invention is represented by the following formula (1).

R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represented by the formula (1) contain hydrogen, an organic functional group containing 1 to 6 carbon atoms, or oxygen, nitrogen or silicon. These are aprotic organic functional groups having 6 or less carbon atoms, which may be the same or different. M in the structural formula is the number of repeating units. A copolymer containing two or more repeating units that are different within the structural range represented by the formula (1) may be used. The phenolic hydroxyl group at the end of the aromatic ether polymer in the present invention is esterified, etherified, epoxidized, etc. as necessary in order to maintain a pH at which the separation target can stably exist in the liquid. Various modifications can be performed. Moreover, from the compatibility with the electrostatic property of the separation target, a chemical structure such as an amino group, a monoalkylamino group, a dialkylamino group, a carboxyl group, or a sulfonyl group can be introduced into the polymer terminal as necessary.

  The number average molecular weight of the aromatic ether polymer is, for example, 5,000 or more and 400,000 or less. If it is this area | region, it can melt | dissolve enough in the good solvent used for film-forming, and sufficient film | membrane intensity | strength as a liquid processing separation membrane is obtained. The more preferable lower limit of the number average molecular weight is 8,000 or more, the particularly preferable lower limit is 10,000 or more, the upper limit is more preferably 200,000 or less, and the more preferable upper limit is 100,000 or less.

  The hydrophilization in the present invention is to improve or impart hydrophilicity.

  The hydrophilizing agent in the present invention is to impart hydrophilicity to the aromatic ether polymer that is a membrane material, and is a liquid treatment comprising a liquid mixture to be subjected to separation treatment and the aromatic ether polymer of the present invention. The contact with the separation membrane is improved. In order to reduce the electrical interaction with the object, it is desirable that the nonionic nature does not include a charged structure.

  Specifically, the hydrophilizing agent in the present invention is polyethylene glycol, polypropylene glycol, polyethylene oxide, polyethylene glycol-polypropylene glycol block copolymer, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, poly-N, N-dimethylacrylamide, poly Examples include poly (meth) acrylamide polymers such as -N-isopropylacrylamide, poly (meth) acrylate polymers such as polyhydroxyacrylate and polyhydroxymethacrylate, carboxymethylcellulose, starch, corn starch, polychitosan, and polychitin. . Among these, polyethylene glycol, polyvinyl pyrrolidone, and polyacrylamide can be suitably used. In addition, surfactants, block copolymers and graft copolymers containing these substances as hydrophilic segments can be sufficiently utilized as hydrophilic agents. Specific examples of the hydrophobic segment of the block copolymer and graft copolymer include poly (meth) acrylate polymers such as polystyrene and polymethyl methacrylate, aromatic polysulfone polymers, aromatic ether polymers, etc. Is mentioned. Among these, a block copolymer and a graft copolymer having polystyrene having high miscibility with an aromatic ether polymer and a hydrophobic segment are preferable, and a polystyrene-polyethylene glycol block copolymer can be suitably used. Moreover, these can also be used in combination of 2 or more types.

  The molecular weight of the hydrophilizing agent in the present invention is 5,000 or more, preferably 8,000 or more, more preferably 10,000 or more as a lower limit, and 1,000,000 or less, preferably 800,000 or less as an upper limit. More preferably, it is 500,000 or less. Within this range, sufficient dissolution in the coagulation liquid and elution from the film after film formation can be reduced.

  The wet film-forming method as a method for producing a liquid treatment separation membrane comprising the aromatic ether polymer of the present invention is a mixture of a membrane stock solution in which a membrane material is dissolved in a good solvent and a good solvent in the membrane stock solution. However, it is a method of obtaining a membrane by bringing about concentration-induced phase separation from the contact surface by bringing it into contact with a coagulation liquid comprising another solvent that is incompatible with the membrane material.

  In the case of using an aromatic ether polymer having a high solvent resistance, finding an optimum production condition in order to stably obtain a uniform film solution and form a film was an extremely important issue.

  As the good solvent used in the wet film-forming method for obtaining the liquid processing separation membrane of the present invention, any solvent can be used as long as it can stably dissolve 5% by weight or more of the aromatic ether polymer as the film material under the film-forming conditions. Can be used. However, it is preferable to use a non-halogen water-soluble organic solvent from the viewpoint of environment and cost. The water-soluble organic solvent in the present invention refers to a solvent that can be dissolved in 10 g or more in 100 g pure water at 20 ° C., and more preferably is miscible with water. Specific examples include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, N, N-dimethylformamide, and γ-butyrolactone. These can be used in combination of two or more.

  As an example of the membrane stock solution used in the wet film formation method for obtaining the polymer membrane of the present invention, when the entire membrane stock solution is 100% by weight, the lower limit of the use range of the aromatic ether polymer is 1% by weight or more. , Preferably 2% by weight or more, particularly preferably 3% by weight or more. Moreover, as an upper limit, the solution which melt | dissolved uniformly in 45 weight% or less, Preferably it is 35 weight% or less, Most preferably, it is 25 weight% or less is used suitably. Further, when a uniformly dissolved solution can be obtained, it is possible to add a hydrophilizing agent.

  The temperature of the membrane stock solution is preferably 25 ° C. or higher, preferably 65 ° C. or higher, particularly preferably 80 ° C. or higher, and the upper limit is preferably the boiling point of the good solvent in the membrane stock solution or lower. By using this temperature condition, the solubility of the aromatic ether polymer can be increased, and a viscosity suitable for processing into a film preferable as a film stock solution can be obtained.

  The coagulating liquid used in the wet film-forming method for obtaining the liquid treatment separation membrane of the present invention is 0.001% by weight or more, preferably 0.005% by weight or more, more preferably 0.01% by weight, with a hydrophilic agent as the lower limit in the solvent. A solution that is uniformly dissolved in an amount of not less than wt% and having an upper limit of not more than 10 wt%, preferably not more than 8 wt%, more preferably not more than 5 wt% is used.

  The solvent used in the coagulation liquid used in the wet film formation method for obtaining the liquid treatment separation membrane of the present invention is a substance that can cause concentration-induced phase separation when in contact with the membrane stock solution and form a membrane from the contact surface, The substance capable of uniformly dissolving the added hydrophilizing agent is shown.

式（２）で示されるＲ^７は、炭素数１以上、２０以下を含む有機官能基、または、酸素原子を１つ以上と炭素数１以上、２０以下とを含む構造であり、Ｒ^７に水酸基、エーテル結合、エステル基、ケトン基、カルボン酸などを１つ以上含んでいてもよい。式（２）に表されるポリオール系溶媒の一例として、エチレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、グリセリン、プロピレングリコール、１，２−ブタンジオール、１，４−ブタンジオールなどが挙げられる。 Specifically, pure water, a monoalcohol solvent, a polyol solvent represented by the following formula (2), or a mixture of two or more of these are preferably used.

R ⁷ of formula (2), the number 1 or more carbon atoms, 20 an organic functional group include the following, or an oxygen atom and 1 or more and having 1 or more carbon atoms, a structure including a 20 or less, the R ⁷ One or more hydroxyl groups, ether bonds, ester groups, ketone groups, carboxylic acids and the like may be contained. Examples of the polyol solvent represented by the formula (2) include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerin, propylene glycol, 1,2-butanediol, 1,4-butanediol, and the like. .

  It is possible to control the water permeation performance by the viscosity of the coagulating liquid used in the wet film forming method for obtaining the liquid processing separation membrane. It has been found that by increasing the viscosity of the coagulation liquid, the permeation of the coagulation liquid into the stock solution becomes gradual, and as a result, the water permeability of the produced membrane is improved. In addition, it has the effect of preventing the formation of macrovoids in the manufactured film. In order to obtain high water permeability, the viscosity of the coagulation liquid is preferably 3 cp or more at 20 ° C. More preferably, it is 5 cp or more.

  Further, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, N, N-dimethylformamide, γ- in the coagulation liquid used in the wet film forming method for obtaining the liquid treatment separation membrane of the present invention. It is also possible to contain a good solvent such as butyrolactone. In particular, when using a coagulation liquid containing a good solvent in a non-solvent, the composition differs depending on the composition of the membrane stock solution, the contact temperature between the membrane stock solution and the coagulation liquid, etc. In this case, the lower limit of 0% by weight and the upper limit of 90% by weight are preferable as the weight% of the good solvent. Within this range, concentration-induced phase separation necessary and sufficient for forming a film can be sufficiently achieved.

The viscosity of the coagulating liquid in the present invention is a value measured using a glass capillary viscometer. As a measuring method, the coagulating liquid is placed in a glass capillary viscometer made constant in a 20 ° C. constant temperature water bath for 30 minutes. The kinematic viscosity can be obtained by performing the measurement as it has reached a constant temperature after being left as described above. From the obtained kinematic viscosity value, the viscosity (η) of the coagulation liquid can be obtained by the following formula. In addition, as a glass capillary viscometer, an Uberote viscometer manufactured by Shibata Kagaku Co., Ltd. can be used.
η = ν × ρ (ν: kinematic viscosity (mm ² / s), η: viscosity (cp), ρ: density (g / cm ³ ))

  The film forming temperature in the wet film forming method of the present invention is a temperature at which the membrane stock solution and the coagulating liquid are brought into contact with each other to cause concentration-induced phase separation. Determined by temperature. In the case of a flat membrane, it is determined by the coagulation liquid temperature. The lower limit of the film formation temperature is 25 ° C. or higher, preferably 80 ° C. or higher, particularly preferably 90 ° C. or higher. The upper limit is a temperature below each boiling point of the membrane stock solution or coagulation liquid, preferably a temperature lower by 5 ° C. or more from each boiling point, particularly preferably a temperature lower by 10 ° C. or more from the boiling point.

  In particular, when the film stock solution and the coagulating liquid are in contact with each other within a film forming temperature of 80 ° C. or higher and a temperature range of 10 ° C. or lower from each boiling point, a particularly high strength film can be obtained.

  Membrane stock solution and coagulation liquid used in the wet film formation method for obtaining the liquid treatment separation membrane of the present invention, particularly coagulation liquid that passes through the inside of the yarn during the production of the hollow fiber membrane (hereinafter referred to as internal coagulation liquid) is dissolved uniformly, It is desirable to remove. By removing the dissolved gas, film defects due to foaming of the dissolved gas can be remarkably improved. Further, by removing oxygen from the dissolved gas, the oxidation reaction to the material due to film processing at a high temperature is reduced.

  In the case of producing a hollow fiber membrane by the wet film-forming method of the present invention, a tank (hereinafter referred to as a coagulation tank) is provided immediately below the spinneret in order to further accelerate the coagulation by the membrane stock solution and the internal coagulation liquid that has come out of the double spinning nozzle. It can be provided and brought into contact with a coagulating liquid (hereinafter referred to as an external coagulating liquid) filled in the coagulating tank.

  When producing a hollow fiber membrane by the wet film-forming method of the present invention, the cross-sectional structure of the hollow fiber membrane is not only a uniform structure but also various non-uniform structures. And the temperature and humidity of the space from the spinneret to the external coagulation liquid surface can be adjusted.

  The lower limit of the free running distance is 0.01 m, preferably 0.05 m, particularly preferably 0.1 m or more, and the upper limit is 2.0 m, preferably 1.5 m, particularly preferably 1.2 m or less. The temperature in the space from the spinneret to the external solidification surface is 20 ° C. or higher, preferably 50 ° C. or higher, particularly preferably 80 ° C. or higher, as the lower limit. The humidity varies depending on the temperature, but the lower limit is 0%, preferably 25%, particularly preferably 50% or more, and the upper limit is 100% or less.

  The winding speed in the case of producing a hollow fiber membrane by the wet film-forming method of the present invention is as follows: various factors that are production conditions, the shape of the spinneret, the composition of the spinning stock solution, the composition of the internal and external coagulating solutions, the stock solution and Although the speed may vary depending on the temperature of each coagulation liquid, a speed of approximately 600 m / hour to 9000 m / hour is selected.

  By using the wet film-forming method of the present invention, a microporous film having sufficient strength and elongation to be provided as a film can be obtained. In addition, by utilizing concentration-induced phase separation in the wet film-forming method of the present invention, it is possible to easily manufacture a porous film structure having an inclined structure, which is difficult to obtain by a melt film-forming method using temperature-induced phase separation. Thus, it is possible to impart high water permeability to the obtained membrane of the present invention.

  In the wet film forming method of the present invention, after coagulation with the coagulating liquid, desolvation can be promoted by immersing in a desolvation tank in order to increase the strength of the film. The solvent removal liquid is a solvent that can remove the remaining solvent after concentration-induced phase separation by the coagulation liquid, and any solvent that does not dissolve the membrane can be used. In general, water, ethanol or the like is often used.

  The film forming temperature in the wet film forming method of the present invention is a temperature at which the membrane stock solution and the coagulating liquid are brought into contact with each other to cause concentration-induced phase separation. That is, it depends on the temperature of the membrane stock solution, the temperature of the coagulation solution, the temperature of the double spinning nozzle if it is a hollow fiber membrane, and the temperature of a metal plate that supports membrane formation if it is a flat membrane. The lower limit of the film formation temperature is 20 ° C. or higher, preferably 25 ° C. or higher, particularly preferably 30 ° C. or higher. The upper limit is a temperature below each boiling point of the membrane stock solution or coagulation liquid, preferably a temperature lower by 5 ° C. or more from each boiling point, particularly preferably a temperature lower by 10 ° C. or more from the boiling point. In particular, when the film stock solution and the coagulating liquid are in contact with each other within a film forming temperature of 80 ° C. or higher and a temperature range of 10 ° C. or lower from each boiling point, a particularly high strength film can be obtained.

  An undried liquid treatment separation membrane of the present invention obtained by a wet film-forming method has a temperature at which membrane breakage during drying does not occur, for example, within a temperature range of 20 ° C. or more to the melting temperature of the aromatic ether polymer or less. Dry with. A preferable drying temperature is 50 ° C. or higher and 150 ° C. or lower, more preferably 60 ° C. or higher and 140 ° C. or lower, and particularly preferably 70 ° C. or higher and 130 ° C. or lower. The time required for drying is determined by the relationship with the drying temperature, but is generally selected from 0.01 hours to 48 hours.

  The form of the liquid treatment separation membrane in the present invention is not particularly limited, but typical examples include a flat membrane and a hollow fiber membrane.

  The liquid treatment separation membrane of the present invention can be used for any liquid separation treatment intended for size separation. Particularly suitable uses are filters used for medical uses, pharmaceutical uses, food and drink uses, and uses related thereto. Specifically, various filters used in medical applications such as plasma filtration, virus removal, and various blood purification applications including hemodialysis, synthetic drug purification processes such as anticancer drugs and antibiotics, highly purified amino acid purification processes for pharmaceuticals, polyclonal antibodies and monoclonals Used in food applications such as various process filters used for pharmaceutical applications such as antibody drug purification processes such as antibodies, filters used in the production of various beverages such as sake, beer, wine, happoshu, tea, oolong tea, vegetable juice and fruit juice Various process filters. In particular, it can be used as a process filter for the purpose of removing aggregates of immunoglobulin as an antibody drug. The blood treatment application in the present invention refers to a blood treatment application such as blood purification, and examples thereof include a plasma filtration filter, a virus removal filter, and a hollow fiber filter for hemodialysis that are included in the above-described medical use.

  The liquid treatment separation membrane comprising a porous aromatic ether polymer of the present invention has a performance as a filter in a region generally referred to as an ultrafiltration membrane or a microfiltration membrane.

  The water permeation performance in the present invention refers to water permeation per unit time, unit area, and unit pressure when water having a viscosity coefficient of 0.0008902 (Pa · s), that is, water at 25 ° C. is permeated through the membrane. Expressed in volume.

[Example]
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Membrane Production Example 1] Flat membrane production method 8.0 g of N-methyl-2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., first grade, purity 97%, hereinafter abbreviated as “NMP”) 0 g of poly (2,6-dimethylphenylene-1,4-oxide) (manufactured by Sigma-Aldrich Japan Co., Ltd., hereinafter abbreviated as “PPE”) was added and dissolved by heating at 160 ° C. for 1 hour, and then a polymer at 90 ° C. A solution was obtained. This polymer solution is gently hung on a glass plate heated to 90 ° C., spread evenly using an applicator, and quickly immersed in a coagulation solution containing 1% by weight of a hydrophilizing agent, which is kept at 90 ° C. did. The polymer precipitated immediately and a white flat film was obtained. This flat membrane was repeatedly immersed and washed five times with pure water at 90 ° C., and then dried for 6 hours with a hot air dryer at 70 ° C.
The type and concentration of the hydrophilizing agent were adjusted as appropriate.

[Membrane Production Example 2] Hollow Fiber Membrane Production Method 430 g of PPE was added to 1600 g of NMP, and the mixture was poured into a 5000 × 10 ⁻⁶ m ³ reactor for membrane stock solution. While stirring the reactor, the pressure reduction to 0.02 MPa and the nitrogen substitution were repeated 5 times. Thereafter, the temperature of the liquid in the reactor was increased to 160 ° C. to obtain a uniform NPE solution of PPE. At this stage, stirring was stopped, and the reactor internal temperature was raised to 90 ° C. over 1 hour with the pressure inside the reactor kept at a reduced pressure of 0.02 MPa. Next, nitrogen was used to bring the pressure inside the reactor to the same pressure as the atmospheric pressure, and a spinning membrane stock solution maintained at 90 ° C. was obtained.

495 g of NMP was mixed with 10 g of a hydrophilizing agent and 495 g of pure water to prepare an internal coagulation liquid (internal liquid), which was added to a 3000 × 10 ⁻⁶ m ³ reactor for the internal liquid. The pressure reduction to 0.02 MPa and nitrogen substitution were repeated 5 times, and then the reactor internal temperature was raised to 90 ° C. while maintaining the pressure reduction of 0.02 MPa. After holding for 1 hour, nitrogen was used to bring the pressure inside the reactor to the same pressure as the atmospheric pressure, and an internal coagulation liquid passing through the inner diameter part held at 90 ° C. was obtained.

From about 60 × 10 ⁻⁶ m ³ / hour of the internal coagulation liquid held at 90 ° C. in the inner diameter part of the double spinning nozzle (inner straight system 100 μm, slit width 50 μm, outer diameter 300 μm) held at 90 ° C. Flow at a flow rate of about 120 × 10 ⁻⁶ m ³ / hour, and then pass the membrane stock solution maintained at 90 ° C. at a flow rate of 90 × 10 ⁻⁶ m ³ / hour to 240 × 10 ⁻⁶ m ³ / hour. It was. Each flow rate was appropriately adjusted according to the winding speed during spinning.

  The obtained hollow fiber membrane was introduced into an external coagulation liquid (pure water) in a coagulation tank held at 90 ° C. with an idle running distance of 0.6 m, and after coagulation was completed, it was wound up by a winding device. It was. The winding speed was 2400 m / hour to 4800 m / hour.

Thereafter, the obtained hollow fiber membrane was repeatedly immersed and washed 5 times using pure water at 80 ° C., and then dried for 6 hours in a hot air dryer at 70 ° C.
The type and concentration of the hydrophilizing agent were adjusted as appropriate.

[Measuring method]
<Measurement method of flat film thickness and porosity>
The film thickness d of the flat film was measured using a micrometer (type IDF-130) manufactured by Mitutoyo Corporation. The porosity of the flat membrane is determined by measuring the weight of the membrane punched into a circle having a diameter of 25 × 10 ⁻³ m, then obtaining the volume of the membrane from the membrane area and thickness, and using the following formula (3), the bulk density of PPE Was calculated as 1.06.

Porosity α (%)
= (1-weight / (resin density x membrane volume)) x 100 (3)

<Measurement method of hollow fiber membrane thickness, inner diameter and porosity>
The film thickness d and the inner diameter of the hollow fiber membrane were measured using a Keyence Corporation laser microscope (VK9700). The porosity of the hollow fiber membrane was determined by measuring the bundle weight of 100 hollow fiber membranes cut to a length of 0.2 m and determining the weight per one. Subsequently, the volume per one was calculated | required from the hollow fiber internal diameter, the film thickness, and length, and it calculated using Formula (3) like a flat film.

<Maximum pore size measurement>
All measurements were performed in a temperature-controlled room controlled at 25 ° C. The maximum pore diameter of each membrane was determined by a bubble point method in which the pores in the membrane having a distribution were filled with liquid and the pressure required to replace the liquid with air was measured. From the surface tension of the liquid used for the measurement and the measurement pressure, the relationship with the pore diameter is determined based on the Laplace equation.
The specific measurement was performed using the bubble point method based on ASTM F316-86. In the case of a flat membrane, a membrane punched into a circle with a diameter of 25 × 10 ⁻³ m is loaded into a flange-shaped membrane holder (effective filtration area 3.5 × 10 ⁻⁴ m ² ), and a fluorocarbon liquid (Sumitomo 3M) Manufactured perfluorocarbon coolant FX-3250, surface tension at 25 ° C. was 10.47 mN / m), the membrane was immersed. One side of the membrane was slowly pressurized with air, the pressure P (Pa) when the gas flow rate permeating the membrane reached 150 × 10 ⁻⁶ m ³ / hour was read, and the maximum pore size was calculated from the following formula (4) . B in the equation is a coefficient, which is 2860 in the following equation.

Maximum pore size (μm)
= B × Surface tension of measurement liquid (mN / m) / Pressure (Pa)
= 2860 x 10.47 / P (4)

For pressure resistance safety of the measuring device, the limit pressure applied to the membrane was 1.5 MPa, and measurement was impossible when gas passage was not recognized by pressurization of 1.5 MPa. In the case of a hollow fiber membrane, the inner surface area was calculated from the inner diameter of the hollow fiber, and the length and number of filtration areas 3.5 × 10 ⁻⁴ m ² were calculated. Next, the required amount of hollow fiber membrane obtained by calculation was loaded into a cylindrical membrane folder, and the operation was performed in the same manner as for a flat membrane.

<Contact angle measurement> The contact angle of water was measured using an automatic contact angle meter (CA-V type) manufactured by Kyowa Interface Science Co., Ltd. In the measurement, pure water 1 × 10 ⁻⁷ m ³ was dropped at an ambient temperature of 25 ° C., and the contact angle after 0.05 hours was measured. The contact angle was calculated using the θ / 2 method.

<X-ray Photoelectron Spectroscopy (XPS) Measurement> A sample is cut into an appropriate size, VG ESCALAB250 manufactured by Thermo Electron is used, the excitation source is AlKα, the X-ray intensity is 15 kV × 10 mA, the analysis area is about 1.0 × 10 ⁻⁶ m ² . Measurement was performed and elemental analysis of the film surface was performed.

According to Membrane Production Example 1, a flat membrane was prepared using an aqueous solution in which 1% by weight of polyethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight of 20,000, hereinafter abbreviated as “PEG”) was dissolved as a coagulating liquid.
The film thickness was 176 μm, the porosity was 78%, the maximum pore diameter was 86 nm, the contact angle with water was 85 °, and hydrophilicity was imparted. The results are shown in Table 1.

According to Membrane Production Example 1, a flat membrane was prepared using an aqueous solution in which 1% by weight of polyvinylpyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd., K30, hereinafter abbreviated as “PVP”) was dissolved as a coagulating liquid.
The film thickness was 169 μm, the porosity was 77%, the maximum pore diameter was 81 nm, the contact angle with water was 77 °, and hydrophilicity was imparted. The results are shown in Table 1.

According to Membrane Production Example 1, a flat membrane was prepared using an aqueous solution in which 1% by weight of polyacrylamide (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 10,000, hereinafter abbreviated as “PAA”) was dissolved as a coagulation liquid. .
The film thickness was 178 μm, the porosity was 71%, the maximum pore diameter was 85 nm, the contact angle with water was 75 °, and hydrophilicity was imparted. The results are shown in Table 1.

According to Membrane Production Method 2, PVP / NMP / water (1 / 69.5 / 29.5% by weight) was used as the internal coagulation liquid, and a hollow fiber membrane was prepared at a winding speed of 4200 m / hour.
The film thickness was 32 μm, the inner diameter was 179 μm, the porosity was 70%, and the maximum pore diameter was 79 nm. As a result of XPS measurement, nitrogen element was observed on the surface, and the inner surface of the hollow fiber was modified with polyvinylpyrrolidone. The results are shown in Table 1.

[Comparative Example 1]
According to Membrane Production Example 1, a flat membrane was prepared using pure water not containing a hydrophilizing agent as a coagulation liquid.
The film thickness was 148 μm, the porosity was 71%, the maximum pore diameter was 69 nm, and the contact angle with water was 97 °. The results are shown in Table 1.

[Comparative Example 2]
According to Membrane Production Method 2, a hollow fiber membrane was prepared using NMP / water (70/30 wt%) without a hydrophilizing agent as an internal coagulation liquid at a winding speed of 4200 m / hour.
The film thickness was 34 μm, the inner diameter was 181 μm, and as a result of XPS measurement, nitrogen element was not observed on the inner surface of the hollow fiber. The results are shown in Table 1.

[Table 1] List of experimental results

Claims (3)

A solution obtained by dissolving 0.001 wt% to 10 wt% of a hydrophilizing agent is used as the coagulation liquid, and consists of an aromatic ether polymer represented by the following formula (1) by a wet film-forming method. A method for producing a hydrophilized liquid treatment separation membrane.

(R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are hydrogen, an organic functional group containing 1 to 6 carbon atoms, or an aprotic having 6 or less carbon atoms containing oxygen, nitrogen or silicon. The organic functional groups may be the same or different, and m is the number of repeating units, and may be a copolymer containing two or more different repeating units.) The method according to claim 1, wherein a hydrophilizing agent having a number average molecular weight of 5,000 or more and 1,000,000 or less is used. The production method according to claim 1 or 2, wherein a polyethylene glycol, polyvinyl pyrrolidone, polyacrylamide, and / or a copolymer containing them as a hydrophilic segment is used as the hydrophilizing agent.