JP2017185475A - Surface-modified porous membrane and method for producing the same - Google Patents

Abstract

The present invention provides a surface-modified porous membrane that is provided with a function by simply introducing a functional polymer layer on the surface of the porous membrane and has excellent durability.
A functional component containing an electrically neutral (apparently no charge) hydrophilic group is selected in a functional polymer layer, and a component having a nitrene precursor functional group is introduced at a specific ratio. And by forming the functional polymer layer with a thickness of 5 to 100 nm on the surface of the porous membrane, the surface-modified porous membrane is imparted with high function and durability.
[Selection figure] None

Description

  The present invention relates to a surface-modified porous membrane and a method for producing the same. By using the present invention, the surface of porous membranes such as microfiltration membranes, ultrafiltration membranes and battery separators used in the fields of water treatment and food / pharmaceutical separation and purification can be easily modified to provide functions. be able to.

  The modification method of the surface of the porous membrane includes a method of coating a functional polymer on the membrane surface, a method of forming a porous membrane after blending the functional polymer with the membrane material, a method of treating with plasma or corona, and a membrane surface. There has been proposed a method of introducing a polymerization initiating group into a graft polymerization and the like. The method of coating the functional polymer is simple and widely used, but the coated functional polymer is easily peeled off from the porous membrane, and it has been difficult to stably maintain the function for a long period of time. After blending the functional polymer with the membrane material, the method of forming the membrane on the separation porous membrane is a simple method that does not require special equipment, but in order to sufficiently coat the membrane surface with the functional polymer, the functional polymer The addition amount must be considerably increased, which tends to cause deterioration of the mechanical properties and chemical resistance of the film, and further increases the cost due to the addition of a large amount of functional polymer. On the other hand, methods using plasma treatment or corona treatment require a large-scale apparatus, and have a drawback that the substrate is easily damaged during the treatment. The method of introducing a polymerization initiating group on the surface and performing graft polymerization is an excellent modification method because it has excellent long-term stability and there is no damage to the substrate, but the method for introducing the polymerization initiating group differs depending on the type of substrate, and is complicated. The disadvantage is that it requires a simple introduction reaction.

  Patent Documents 1 and 2 describe a method for introducing a functional polymer onto a substrate surface using a nitrene insertion reaction as a method for improving the drawbacks of the conventional modification method. This method is excellent in that the functional polymer can be introduced to the substrate surface via a covalent bond by a simple method such as functional polymer coating and UV irradiation. However, because the nitrene insertion reaction is consumed not only by the reaction with the substrate at the substrate interface but also by the internal crosslinking of the functional polymer, there are many functional polymers introduced and immobilized. However, there was a case where the function did not appear. In addition, it has a drawback that it is inferior in durability and function as compared with other surface modification methods.

Japanese Patent Publication No. 3-505979 JP 2010-59346 A

  It is an object of the present invention to produce and provide a surface-modified porous membrane that imparts a function by simply introducing a functional polymer layer on the surface of the porous membrane and is excellent in durability.

  As a result of intensive studies by the present inventors to achieve the above object, a functional component containing a hydrophilic group that is electrically neutral (apparently has no charge) in the functional polymer layer is selected. Introducing a component having a nitrene precursor functional group at a specific ratio, and forming a functional polymer layer with a thickness of 5 to 100 nm on the surface of the porous membrane, it is highly functional and durable to the surface-modified porous membrane The present inventors have found that it is possible to impart properties, and have completed the present invention.

That is, the present invention
[1] A porous membrane and a functional polymer layer formed on the surface of the porous membrane via a covalent bond, wherein the functional polymer layer contains a functional component containing a hydrophilic group and the porous membrane and nitrene. A surface-modified porous membrane containing a crosslinking component produced by a reaction, wherein the functional polymer layer contains 5 to 30 mol% of a crosslinking component, and the thickness of the functional polymer layer is 5 to 100 nm. A surface-modified porous membrane.
[2] A monomer in which the functional component introduced into the functional polymer layer has a functional group selected from an alkoxyalkyl group, a monoalkoxypolyoxyethylene group, a polyoxyethylene group, or a betaine group, and a vinyl group. The surface-modified porous membrane according to [1], which is a polymer of
[3] The surface according to [1] or [2], wherein the crosslinking component introduced into the functional polymer layer is a polymer of a monomer having a nitrene precursor functional group and a vinyl group. Modified porous membrane.
[4] The surface according to any one of [1] to [3], wherein the component introduced into the functional polymer layer is a polymer having a structure represented by the general formula (1) Modified porous membrane.
(In the formula, m and n each independently represent an integer of 1 or more, X represents a phenylene group which may have a substituent, or a group represented by an ester bond or an amide bond, and Y represents a betaine group. Represents a hydrophilic group selected from an alkoxyalkyl group, an alkoxypolyoxyethylene group, and a hydroxypolyoxyethylene group, Z represents a group represented by —O— or —N (R ₃ ) —, and A represents —O -Or -CH _2- represents a group, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a C ₁ -C ₆ hydrocarbon group, and R ₄ is a C ₃ -C ₆ Represents a divalent hydrocarbon group, R ₅ represents a fluorine atom, and p represents an integer of 0 to 4.)

［５］膜分離活性汚泥法に用いられることを特徴とする、［１］〜［４］のいずれかに記載の表面修飾多孔質膜。
［６］［１］〜［５］のいずれかに記載の表面修飾多孔質膜からなる水処理分離膜。
［７］機能性成分と５〜３０モル％のニトレン前駆体官能基を有する成分からなる機能性ポリマーを多孔質膜表面に存在させ、光照射により多孔質膜表面に共有結合を介して機能性ポリマー層を形成することを特徴とする、［１］〜［４］のいずれかに表面修飾多孔質膜の製造方法。

[5] The surface-modified porous membrane according to any one of [1] to [4], which is used in a membrane separation activated sludge method.
[6] A water treatment separation membrane comprising the surface-modified porous membrane according to any one of [1] to [5].
[7] A functional polymer composed of a functional component and a component having a nitrene precursor functional group of 5 to 30 mol% is present on the surface of the porous membrane, and is functionalized by covalent irradiation on the porous membrane surface by light irradiation. A method for producing a surface-modified porous membrane according to any one of [1] to [4], wherein a polymer layer is formed.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
The surface-modified porous membrane of the present invention comprises a porous membrane and a functional polymer layer formed on the membrane surface.

  The material of the porous film used in the present invention is not particularly limited, but it needs to have a site that reacts with nitrene generated by UV irradiation of the functional polymer. The site that reacts with nitrene refers to carbon-hydrogen bonds or nitrogen-hydrogen bonds, and metals such as aluminum, iron, stainless steel, titanium, gold, platinum, silver, copper, silica, alumina, zirconia, titania, silicon nitride, silicon In the case of a porous film made of an inorganic material such as glass or carbon fiber, it is necessary to introduce a reaction site on the film surface using an alkyl mercaptan or a silane coupling agent. On the other hand, in the case of a porous film made of an organic polymer, there is no such need and it can be used as it is. Some examples of organic polymers include polyethylene, chlorinated polyethylene, polypropylene, polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, styrene-acrylonitrile copolymers, ABS, polymethyl methacrylate, Cellulose acetate, cellulose, polyvinylidene fluoride, polytetrafluoroethylene, polysulfone, polyethersulfone, polyphenylene sulfide, polyphenylene ether, polyetheretherketone, polycarbonate, polyacetal, polyester, polyamide, polyimide, polyurethane, epoxy resin, phenol resin, Saturated polyester etc. are mentioned.

  Examples of the shape of the porous membrane include a flat membrane-like porous membrane and a hollow fiber-like porous membrane, and in particular, a porous membrane used as a microfiltration membrane or an ultrafiltration membrane is preferably used in the present invention. The microfiltration membrane mentioned here is a porous membrane having a pore diameter of about 0.05 to 10 μm, and the material is polyethylene, polypropylene, polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene. Organic polymers such as polyacrylonitrile, polycarbonate, polysulfone, and cellulose acetate, and ceramics such as alumina are used. On the other hand, the ultrafiltration membrane is a porous membrane having a pore size of about 2 to 50 nm, and the material is polyethylene, polyacrylonitrile, polyvinyl chloride, polyvinyl chloride-polyacrylonitrile copolymer, polysulfone, polyethersulfone, Organic polymers such as polyvinylidene fluoride, aromatic polyamide, polyimide, and cellulose acetate, and ceramics such as alumina are used.

  In many cases, microfiltration membranes have a uniform porous structure, whereas ultrafiltration membranes have an asymmetric membrane structure in which the porous structure differs between the dense layer on the surface and the inner support layer. Yes. Furthermore, a composite film in which two or more kinds of materials are combined may be used. As the composite membrane, a membrane in which a porous layer, which is a separation functional layer, and a base material for reinforcing the composite layer is preferably used. Examples of the base material used for reinforcement include polyester fibers, nylon fibers, polyurethane fibers, acrylic fibers, rayon fibers, cotton, silk and other organic fibers and their woven fabrics, knitted fabrics, non-woven fabrics, glass fibers, metal fibers, etc. And inorganic fibers such as those and their woven and knitted fabrics. Some examples of composite membranes include a flat membrane ultrafiltration membrane that combines a polyester non-woven fabric with a polyethersulfone porous membrane and a flat membrane-shaped microfiltration membrane that combines a polyester non-woven fabric with a polyvinylidene fluoride porous membrane, Examples thereof include a hollow fiber microfiltration membrane in which a polyester braid is combined with a polyvinylidene fluoride porous membrane.

  A battery separator is also preferably used as the porous membrane used in the present invention. The battery separator is a porous membrane that separates the positive electrode and the negative electrode in the battery and retains the electrolytic solution to ensure ionic conductivity between the positive electrode and the negative electrode, and has a pore diameter of about 0.05 to 1 μm. It is. Examples of the material of the membrane include polyethylene, polypropylene, cellulose, aromatic polyamide, and the like, and these materials are laminated and composited by coating.

  The thickness of the porous film is not particularly limited as long as light reaches the inside, and can be selected in the range of 1 to 500 μm.

  The functional polymer layer used in the present invention is a polymer layer formed through a covalent bond on the surface of the porous membrane and has a function including an electrically neutral (apparently no charge) hydrophilic group. A functional component having, for example, an alkoxyalkyl group, a monoalkoxypolyoxyethylene group, a polyoxyethylene group or a betaine group, and a crosslinking component produced by the reaction of nitrene. Specific examples of the alkoxyalkyl group that is a functional component include a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, and an ethoxyethyl group.

  Specific examples of the monoalkoxypolyoxyethylene group include 2- (2-methoxyethoxy) ethyl group, 2- (2-ethoxyethoxy) ethyl group, 2- {2- (2-methoxyethoxy) ethoxy} ethyl. Group, methoxypolyoxyethylene group, ethoxypolyoxyethylene group and the like. Specific examples of the polyoxyethylene group include 2- (2-hydroxyethoxy) ethyl group, 2- {2- (2-hydroxyethoxy) And ethoxy} ethyl group, ω-hydroxypolyoxyethylene group and the like.

  A betaine group has a positively charged portion and a negatively charged portion in an ionized state at non-adjacent positions in the same group, and a dissociable hydrogen atom is bonded to a positively charged atom. In general, it refers to a group that is electrically neutral (has no charge) as a whole. Specific examples of this betaine group include a sulfobetaine group, a carbobetaine group, and a phosphobetaine group.

  In the present invention, the term “functional component” refers to the functions of imparting hydrophilicity and wettability to the electrolyte solution, inhibiting protein adsorption, preventing biofouling, antithrombogenicity, biocompatibility, antistatic properties, etc. It is a component for imparting to the film and contains a hydrophilic group that is electrically neutral (apparently has no charge).

  In the present invention, the term “crosslinking component” means that a component having a nitrene precursor functional group generates nitrene by light irradiation, and the nitrene is inserted into a carbon-hydrogen bond or a nitrogen-hydrogen bond to form a covalent bond. It is an ingredient. It is important that the cross-linking component is contained in the functional polymer at a ratio of 5 to 30 mol% in order to exhibit the effects of the present invention. If the cross-linking component is less than 5 mol%, it is not preferable because the functional polymer layer is insufficiently immobilized on the porous membrane surface. On the other hand, if it exceeds 30 mol%, protein adsorption suppression and biofouling are not preferable. It is not preferable because the function such as prevention of occurrence and antithrombogenicity is reduced.

  In the present invention, the “functional polymer layer” refers to a polymer layer composed of the above “functional component” and “crosslinking component” and formed on the surface of the porous membrane via a covalent bond. By forming the functional polymer layer on the surface of the porous membrane, various functions derived from the functional component can be immobilized and introduced on the surface of the porous membrane.

  The functional polymer layer formed on the porous membrane surface has a thickness of 5 to 100 nm. If the thickness of the polymer layer is less than 5 nm, the function to be imparted is not sufficiently exhibited, which is not preferable. On the other hand, if the thickness of the polymer layer exceeds 100 nm, it is not preferable because not only higher functionality cannot be expected, but also the pores of the porous membrane may be blocked. When the thickness of the polymer layer is less than 10 nm, functions such as imparting hydrophilicity and wettability to the electrolyte solution, inhibiting protein adsorption, preventing biofouling, antithrombogenicity, biocompatibility, antistatic properties, etc. Although it develops, it may be inferior in durability when used for a long time under severe conditions. On the other hand, when the thickness is 10 nm or more, the durability is improved, and the deterioration of the function can be suppressed even when used for a long time under harsh conditions.

  In particular, the porous membrane used in the membrane separation activated sludge method (hereinafter abbreviated as MBR) is very dirty and is severe such as repeated washing with a high concentration sodium hypochlorite aqueous solution to prevent membrane clogging. However, even in such applications, the function can be maintained for a long time by setting the thickness of the functional polymer layer to 10 to 100 nm.

  The method for producing a surface-modified porous membrane according to the present invention is characterized in that a functional polymer is present on the surface of the porous membrane, and a functional polymer layer is formed on the surface of the porous membrane via a covalent bond by light irradiation. .

  The method for allowing the functional polymer to be present on the surface of the porous membrane is not particularly limited, and a method of coating the porous membrane as it is or after diluting with a solvent can be used. The coating method is not particularly limited, and can be selected from dip coating, spin coating, gravure coating, roll coating, bar coating, die coating, knife coating, etc. according to the shape of the porous film and the viscosity of the functional polymer (solution) to be coated. Just do it. When the functional polymer is diluted with a solvent and used for coating, it is preferable to remove the solvent by drying or the like before light irradiation.

After the functional polymer is present on the surface of the porous membrane by the above method, light is irradiated. The light needs to be light having a wavelength that allows the photoreactive group to be used to generate nitrene. When an azide group is used as the photoreactive group, the light is irradiated with ultraviolet rays having a wavelength of 10 to 400 nm, preferably 250 to 380 nm. . Although the intensity | strength of the ultraviolet-ray to irradiate is not specifically limited, It can select suitably in the range of 1-1000 mW / cm < ² >.

  The molecular weight of the functional polymer used in the present invention can be selected in the range of 1,000 to 1,000,000, but from the viewpoint of viscosity and solubility during coating, and mechanical strength of the polymer layer, 5,000 to 500, A range of 000 is preferred. The functional polymer is a copolymer of a functional component and a crosslinking component, but they may be arranged randomly or in a block form. The functional polymer is soluble in water, but may be water-soluble or water-insoluble. For example, when the functional component is water-soluble and the proportion of the crosslinking component is low, it becomes water-soluble, but when the functional component is insoluble in water and the proportion of the crosslinking component is high, it does not dissolve in water.

  As a functional component constituting the functional polymer of the present invention, a functional group selected from an alkoxyalkyl group, a monoalkoxypolyoxyethylene group, a polyoxyethylene group, a sulfobetaine group, a carbobetaine group, and a phosphobetaine group and a vinyl group A monomer polymer having the following can be used. Examples of the vinyl group include a methacryloxy group, a methacrylamide group, an acryloxy group, an acrylamide group, and a styryl group. However, methacryloxy group has a high mechanical strength and is excellent in affinity with a porous film. Group and acryloxy group are preferred.

  Specific examples of the monomer include methoxyethyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylamide, methoxyethyl acrylamide, 2-methoxyethoxystyrene, 2- (2-methoxyethoxy) ethyl methacrylate, 2- (2-methoxyethoxy) Ethyl acrylate, 2- (2-methoxyethoxy) ethyl methacrylamide, 2- (2-methoxyethoxy) ethyl acrylamide, 2- (2-methoxyethoxy) ethoxystyrene, polyethylene glycol methyl ether methacrylate, polyethylene glycol methyl ether acrylate, polyethylene Glycol methyl ether methacrylamide, polyethylene glycol methyl ether acrylamide, polyethylene glycol ethyl ether Methacrylate, polyethylene glycol ethyl ether acrylate, polyethylene glycol ethyl ether methacrylamide, polyethylene glycol ethyl ether acrylamide, 2- (2-hydroxyethoxy) ethyl methacrylate, 2- (2-hydroxyethoxy) ethyl acrylate, 2- (2-hydroxy Ethoxy) ethyl methacrylamide, 2- (2-hydroxyethoxy) ethyl acrylamide, 2- (2-hydroxyethoxy) ethoxy styrene, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylamide, polyethylene glycol monoacrylamide, N -Methacryloyl-L-histidine, 2-methacryloyloxyethyl Suhorirukorin, 2- (N-3- sulfopropyl -N, N-dimethylammonium) ethyl methacrylate, 2-(N-carbomethoxy -N, N-dimethylammonium) ethyl methacrylate.

  As a crosslinking component constituting the functional polymer of the present invention, a polymer of a monomer having a nitrene precursor functional group and a vinyl group can be used. The nitrene precursor functional group is an azide group, specifically, aryl azides such as phenyl azide and tetrafluorophenyl azide; acyl azides such as benzoyl azidomethyl benzoyl azide; Although sulfonyl azides, such as benzene sulfonyl azide, are mentioned, Preferably an aryl azide is used. Examples of the vinyl group include a methacryloxy group, a methacrylamide group, an acryloxy group, an acrylamide group, and a styryl group. In the case where the functional component is a polymer of a monomer having a methacryloxy group or an acryloxy group, A methacryloxy group and an acryloxy group are preferable from the viewpoint of enhancing the polymerizability.

  Specific examples of the monomer include methacryloyloxypropyloxy 4-phenylazide, acryloyloxypropyloxy 4-phenylazide, methacrylamidepropyloxy 4-phenylazide, acrylamidopropyloxy 4-phenylazide, methacryloyloxyethyloxy 4-phenyl Azide, acryloyloxyethyloxy 4-phenylazide, methacrylamidoethyloxy 4-phenylazide, acrylamidoethyloxy 4-phenylazide, methacryloyloxyethyloxycarboxy 4-phenylazide, acryloyloxyethyloxycarboxy 4-phenylazide, methacrylamide Ethyloxycarboxy 4-phenylazide, acrylamide ethyloxycarboxy 4-phenylazide, Tacryloyloxyethyl 4-phenylazide, acryloyloxyethyl 4-phenylazide, methacrylamidoethyl 4-phenylazide, acrylamidoethyl 4-phenylazide, methacryloyloxypropyl 4-phenylazide, acryloyloxypropyl 4-phenylazide, methacrylamide Propyl 4-phenylazide, acrylamidopropyl 4-phenylazide, methacryloyloxybutyl 4-phenylazide, acryloyloxybutyl 4-phenylazide, methacrylamidobutyl 4-phenylazide, acrylamidobutyl 4-phenylazide, methacryloyloxyethyloxycarboxy 2 , 3,5,6-tetrafluoro-4-phenylazide, acryloyloxyethyloxycarboxy 2,3 , 6-tetrafluoro-4-phenyl azide, methacrylamidoethyloxycarboxy 2,3,5,6-tetrafluoro-4-phenyl azide, acrylamidoethyloxycarboxy 2,3,5,6-tetrafluoro-4-phenyl Azide, methacryloyloxypropyloxy 2,3,5,6-tetrafluoro-4-phenylazide, acryloyloxypropyloxy 2,3,5,6-tetrafluoro-4-phenylazide, methacrylamidepropyloxy 2,3 5,6-tetrafluoro-4-phenyl azide, acrylamidopropyloxy 2,3,5,6-tetrafluoro-4-phenyl azide, methacrylamide 4-phenyl azide, acrylamide 4-phenyl azide, methacrylamide 2,3 5,6-tetrafluoro Examples include rho-4-phenyl azide, acrylamide 2,3,5,6-tetrafluoro-4-phenyl azide and the like.

  The functional polymer used in the present invention is a copolymer of the monomers exemplified above, but is preferably a polymer having a structure represented by the general formula (1).

（式中、ｍ及びｎは互いに独立して１以上の整数を表し、Ｘは置換基を有しても良いフェニレン基、又はエステル結合若しくはアミド結合で示される基を表し、Ｙはベタイン性基、アルコキシアルキル基、アルコキシポリオキシエチレン基、ヒドロキシポリオキシエチレン基から選ばれた親水性基を表し、Ｚは−Ｏ−又は−Ｎ（Ｒ_３）−で示される基を表し、Ａは−Ｏ−又は−ＣＨ_２−で示される基を表し、Ｒ_１、Ｒ_２及びＲ_３は互いに独立して水素原子又はＣ_１〜Ｃ_６の炭化水素基を表し、Ｒ_４はＣ_３〜Ｃ_６の２価の炭化水素基を表し、Ｒ_５はフッ素原子を表し、ｐは０〜４の整数を表す。）
Ｘで表される置換基を有しても良いフェニレン基の置換基として、特に限定されないが、アルキル基（例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基等）、アルコキシ基（例えば、メトキシ基、エトキシ基、プロポキシ基、イソプロポキシ基等）、ハロゲン原子（例えば、フッ素原子、塩素原子、臭素原子、ヨウ素原子）、カルボキシ基、アミノ基、ヒドロキシ基等が例示される。Ｘとしては、エステル結合が好ましい。

(In the formula, m and n each independently represent an integer of 1 or more, X represents a phenylene group which may have a substituent, or a group represented by an ester bond or an amide bond, and Y represents a betaine group. Represents a hydrophilic group selected from an alkoxyalkyl group, an alkoxypolyoxyethylene group, and a hydroxypolyoxyethylene group, Z represents a group represented by —O— or —N (R ₃ ) —, and A represents —O -Or -CH _2- represents a group, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a C ₁ -C ₆ hydrocarbon group, and R ₄ is a C ₃ -C ₆ Represents a divalent hydrocarbon group, R ₅ represents a fluorine atom, and p represents an integer of 0 to 4.)
Although it does not specifically limit as a substituent of the phenylene group which may have a substituent represented by X, For example, an alkyl group (For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, sec- Butyl group, tert-butyl group etc.), alkoxy group (eg methoxy group, ethoxy group, propoxy group, isopropoxy group etc.), halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), carboxy group , Amino group, hydroxy group and the like. X is preferably an ester bond.

  Examples of the hydrophilic group represented by Y include a betaine group, an alkoxyalkyl group, an alkoxypolyoxyethylene group, and a hydroxypolyoxyethylene group. In the present invention, the term “betaine” means that a portion having a positive charge and a portion having a negative charge in an ionized state are not adjacent to each other in the same group and can be dissociated into atoms having a positive charge. It means that the atoms are not bonded and are neutral as a whole (has no charge). The betaine group is not particularly limited, and examples thereof include a carbobetaine group, a sulfobetaine group, a phosphobetaine group, and an amide betaine group. Although it does not specifically limit as an alkoxyalkyl group, 2-methoxyethyl group, 3-methoxypropyl group, 4-methoxybutyl group is illustrated. The alkoxy polyoxyethylene group is not particularly limited, and examples thereof include a methoxy polyoxyethylene group, an ethoxy polyoxyethylene group, a normal propoxy polyoxyethylene group, and an isopropoxy polyoxyethylene group. An oxyethylene group is preferred.

R _{1, R 2} and is not particularly restricted but includes hydrocarbon groups _C 1 -C ₆ represented by _{R 3,} methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, sec-butyl group, tert-butyl group, cyclobutyl group, pentyl group, neopentyl group, isopentyl group, 1-methylbutyl group, 1-ethylpropyl group, cyclobutylmethyl group, cyclopentyl group, hexyl group, 1-methylpentyl group, Examples include 4-methylpentyl group, 1-ethylbutyl group, 2-ethylbutyl group, cyclohexyl group, and phenyl group.

The C _{3 to} C ₆ divalent hydrocarbon group represented by R ₄ is not particularly limited, but — (CH ₂ ) ₃ —, — (CH ₂ ) ₄ —, — (CH ₂ ) ₅ —, — Examples include (CH ₂ ) _6- , a phenylene group, and the like. If the carbon number of the divalent hydrocarbon group represented by R ₄ is 2 or less, the glass transition temperature of the photoreactive polymer is increased and the molecular mobility of the side chain is decreased. Is consumed in the crosslinking reaction between the photoreactive polymers rather than the reaction with the base material, and the photoreactive polymer immobilization rate on the surface of the base material is decreased. On the other hand, when the carbon number of the divalent hydrocarbon group represented by R ₄ exceeds 6, the concentration of the azide group in the photoreactive polymer is lowered, the number of crosslinking points is reduced, and the photoreactive polymer on the substrate surface is reduced. Since the immobilization rate is lowered, it is not preferable.

  In the photoreactive polymer having the structure represented by the general formula (1), m and n each independently represent an integer of 1 or more. Here, the value of m / (m + n) is preferably 0.02 to 0.7, and more preferably 0.05 to 0.5. If it is this range, it is excellent at the point of coexistence of the adhesiveness to a base material, and the protein adsorption | suction suppression effect.

  The following general formula (2) included in the general formula (1)

（式中、Ｒ_１、Ｘ、Ｙ及びｎは前記と同じ意味を表す。）で表される構造単位としては、特に限定されないが、ポリエチレングリコールメチルエーテルメタクリレート、ポリエチレングリコールメタクリレート、ポリエチレングリコールメチルエーテルアクリレート、ポリエチレングリコールアクリレート、２−ヒドロキシエチルメタクリレート、２−メタクリロイルオキシエチルホスホリルコリン、２−アクリロイルオキシエチルホスホリルコリン、［２−（メタクリロイルオキシ）エチル］ジメチル−（３−スルホプロピル）アンモニウムヒドロキシド、Ｎ−メタクリロイルオキシエチル−Ｎ，Ｎ−ジメチルアンモニウム−α−Ｎ−メチルカルボキシベタイン等のモノマーに由来する構造単位が例示され、タンパク質吸着抑制効果の点から、ポリエチレングリコールメチルエーテルメタクリレートや２−メタクリロイルオキシエチルホスホリルコリン、［２−（メタクリロイルオキシ）エチル］ジメチル−（３−スルホプロピル）アンモニウムヒドロキシド、Ｎ−メタクリロイルオキシエチル−Ｎ，Ｎ−ジメチルアンモニウム−α−Ｎ−メチルカルボキシベタインに由来する構造単位が好ましい。

The structural unit represented by (wherein R ₁ , X, Y and n represent the same meaning as described above) is not particularly limited, but polyethylene glycol methyl ether methacrylate, polyethylene glycol methacrylate, polyethylene glycol methyl ether acrylate , Polyethylene glycol acrylate, 2-hydroxyethyl methacrylate, 2-methacryloyloxyethyl phosphorylcholine, 2-acryloyloxyethyl phosphorylcholine, [2- (methacryloyloxy) ethyl] dimethyl- (3-sulfopropyl) ammonium hydroxide, N-methacryloyloxy Examples of structural units derived from monomers such as ethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine, etc. Polyethylene glycol methyl ether methacrylate, 2-methacryloyloxyethyl phosphorylcholine, [2- (methacryloyloxy) ethyl] dimethyl- (3-sulfopropyl) ammonium hydroxide, N-methacryloyloxyethyl-N, N-dimethylammonium-α A structural unit derived from -N-methylcarboxybetaine is preferred.

  The following general formula (3) included in the general formula (1)

（式中、Ｒ_２、Ｒ_４、Ｒ_５、Ａ、Ｚ、ｍ及びｐは前記と同じ意味を表す。）で表される構造単位としては、特に限定されないが、３−（４−アジドフェノキシ）プロピルメタクリレート、４−（４−アジドフェノキシ）ブチルメタクリレート、５−（４−アジドフェノキシ）ペンチルメタクリレート、６−（４−アジドフェノキシ）ヘキシルメタクリレート、３−（４−アジド−２，３，５，６−テトラフルオロフェノキシ）プロピルメタクリレート、４−（４−アジドフェニル）ブチルメタクリレート、４−（４−アジド−２，３，５，６−テトラフルオロフェニル）ブチルメタクリレート、３−（４−アジドフェノキシ）プロピルアクリレート、４−（４−アジドフェニル）ブチルアクリレート、３−（４−アジドフェノキシ）プロピルメタクリルアミド、３−（４−アジド−２，３，５，６−テトラフルオロフェノキシ）プロピルメタクリルアミド、３−（４−アジドフェノキシ）プロピルアクリルアミド、４−（４−アジドフェニル）ブチルメタクリルアミド、４−（４−アジドフェニル）ブチルアクリルアミド等のモノマーに由来する構造単位が例示され、アジドの光分解速度の点から、３−（４−アジドフェノキシ）プロピルメタクリレートに由来する構造単位が好ましい。

The structural unit represented by (wherein R ₂ , R ₄ , R ₅ , A, Z, m and p have the same meaning as described above) is not particularly limited, but 3- (4-azidophenoxy) ) Propyl methacrylate, 4- (4-azidophenoxy) butyl methacrylate, 5- (4-azidophenoxy) pentyl methacrylate, 6- (4-azidophenoxy) hexyl methacrylate, 3- (4-azido-2,3,5, 6-tetrafluorophenoxy) propyl methacrylate, 4- (4-azidophenyl) butyl methacrylate, 4- (4-azido-2,3,5,6-tetrafluorophenyl) butyl methacrylate, 3- (4-azidophenoxy) Propyl acrylate, 4- (4-azidophenyl) butyl acrylate, 3- (4-azidophenoxy) pro Methacrylamide, 3- (4-azido-2,3,5,6-tetrafluorophenoxy) propyl methacrylamide, 3- (4-azidophenoxy) propyl acrylamide, 4- (4-azidophenyl) butyl methacrylamide, Examples include structural units derived from monomers such as 4- (4-azidophenyl) butylacrylamide, and structural units derived from 3- (4-azidophenoxy) propyl methacrylate are preferred from the viewpoint of the photodegradation rate of azide.

  The arrangement of the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3) is not particularly limited, and may be any order of random, block, and alternating.

  The number average molecular weight of the photoreactive polymer having the structure represented by the general formula (1) can be selected in the range of 1,000 to 1,000,000, but the viscosity and solubility during coating, and the mechanical strength of the polymer layer In view of the above, the range of 10,000 to 500,000 is preferable. Further, the polydispersity (Mw / Mn) represented by the ratio of the mass average molecular weight (Mw) to the number average molecular weight (Mn) is not particularly limited, but for example, adhesion to a hydrophobic substrate. From the viewpoint of the stability of the coating film, about 1 to 5 is preferable.

  The photoreactive polymer having the structure represented by the general formula (1) may have a structural unit derived from another monomer without departing from the effect of the present invention. The structural units derived from other monomers are not particularly limited, but polystyrene, poly (α-methylstyrene), polyvinyl benzyl chloride, polyvinyl aniline, sodium polystyrene sulfonate, polyvinyl benzoic acid, polyvinyl phosphoric acid, polyvinyl pyridine, polydimethyl. Styrenic polymers such as aminomethylstyrene and polyvinylbenzyltrimethylammonium chloride; polyolefins such as polyethylene, polypropylene, polybutadiene, polybutene, and polyisoprene; poly (halogenated olefins) such as polyvinyl chloride, polyvinylidene chloride, and polytetrafluoroethylene; Polyvinyl esters such as polyvinyl acetate and polyvinyl propionate, and saponified polyvinyl alcohol, such as polyacrylonitrile (Meth) acrylic polymers such as polymethacrylic acid, polyperfluoroalkyl methacrylate, polyethyl acrylate, polyacrylic acid, polydimethylaminoethyl acrylate; polyacrylamide, polymethacrylamide, polydimethylaminopropyl acrylamide, And (meth) acrylamide polymers and the like.

  Examples of the photoreactive polymer of the present invention include a photoreactive polymer having a structure represented by the general formula (4).

（式中、ｍ、ｎ、ｒ及びＲ_４は前記と同じ意味を表す。）
ｒの値は、重合の進行しやすさから、２〜２０の範囲の整数が好ましい。Ｒ_４は、−（ＣＨ_２）_３−または−（ＣＨ_２）_４−であることが好ましく、更に好ましくは−（ＣＨ_２）_３−である。

(In the formula, m, n, r and R ₄ have the same meaning as described above.)
The value of r is preferably an integer in the range of 2 to 20 from the ease of polymerization. R ₄ is preferably — (CH ₂ ) ₃ — or — (CH ₂ ) ₄ —, more preferably — (CH ₂ ) ₃ —.

  The photoreactive polymer having the structure represented by the general formula (1) can be produced by a conventional method basically based on the technical level of those skilled in the art, including preparation of monomer compounds and polymerization thereof. For example, the monomer used is not particularly limited, but polyethylene glycol methyl ether methacrylate, polyethylene glycol methacrylate, polyethylene glycol methyl ether acrylate, polyethylene glycol acrylate, 2-hydroxyethyl methacrylate, 2-methacryloyloxyethyl phosphorylcholine, 2-acryloyloxyethyl. Has a hydrophilic group such as phosphorylcholine, [2- (methacryloyloxy) ethyl] dimethyl- (3-sulfopropyl) ammonium hydroxide, N-methacryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine Monomer, 3- (4-azidophenoxy) propyl methacrylate, 4- (4-azidophenoxy) butyl Tacrylate, 5- (4-azidophenoxy) pentyl methacrylate, 6- (4-azidophenoxy) hexyl methacrylate, 3- (4-azido-2,3,5,6-tetrafluorophenoxy) propyl methacrylate, 4- (4 -Azidophenyl) butyl methacrylate, 4- (4-azido-2,3,5,6-tetrafluorophenyl) butyl methacrylate, 3- (4-azidophenoxy) propyl acrylate, 4- (4-azidophenyl) butyl acrylate , 3- (4-azidophenoxy) propyl methacrylamide, 3- (4-azido-2,3,5,6-tetrafluorophenoxy) propyl methacrylamide, 3- (4-azidophenoxy) propyl acrylamide, 4- ( 4-Azidophenyl) butylmethacrylamide Monomer having a photoreactive group such as 4- (4-azidophenyl) butylacrylamide is used.

  The polymerization is not particularly limited, and examples thereof include radical polymerization, ionic polymerization, and coordination polymerization. From the viewpoint of ease of operation, radical polymerization, particularly free radical polymerization or living radical polymerization is preferably used. The polymerization initiator is not particularly limited. For example, 2,2′-azobisisobutyronitrile (AIBN), benzoyl peroxide, diisopropyl peroxydicarbonate, tert-butylperoxy-2-ethylhexanoate, tert Known radical initiators such as -butyl peroxypivalate, tert-butyl peroxydiisobutyrate, persulfate or persulfate-bisulfite can be used. As a polymerization solvent, for example, a known radical polymerization solvent such as water, THF, dioxane, acetone, 2-butanone, ethyl acetate, isopropyl acetate, benzene, toluene, DMF, DMSO, methanol, ethanol, isopropanol or a mixture thereof is used. For example, it can be manufactured by diluting the monomer concentration to 0.01 to 5 mol / L and the polymerization initiator concentration to 1 to 100 mmol / L and reacting at 0 to 80 ° C. for 1 to 72 hours. . Moreover, there is no restriction | limiting in particular as a superposition | polymerization form, For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, dispersion polymerization, precipitation polymerization is illustrated, and solution polymerization is preferably used from the simplicity of operation.

  Examples of the functional polymer represented by the general formula (1) include polyethylene glycol methyl ether methacrylate / methacryloyloxypropyloxy 4-phenylazide copolymer, 2-methacryloyloxyethyl phosphorylcholine / methacryloyloxypropyloxy 4-phenylazide copolymer Polymer, 2- (N-3-sulfopropyl-N, N-dimethylammonium) ethyl methacrylate / methacryloyloxypropyloxy 4-phenylazide copolymer, 2- (N-carbomethoxy-N, N-dimethylammonium) Ethyl methacrylate / methacryloyloxypropyloxy 4-phenylazide copolymer, polyethylene glycol methyl ether methacrylate / methacryloyloxybutyl 4-phenylazide copolymer, 2 Methacryloyloxyethyl phosphorylcholine / methacryloyloxybutyl 4-phenylazide copolymer, 2- (N-3-sulfopropyl-N, N-dimethylammonium) ethyl methacrylate / methacryloyloxybutyl 4-phenylazide copolymer, 2- ( N-carbomethoxy-N, N-dimethylammonium) ethyl methacrylate / methacryloyloxybutyl 4-phenylazide copolymer and the like.

  When the copolymerization property of the monomer constituting the functional component and the monomer having the nitrene precursor functional group is good, the monomer charge ratio is such that the monomer having the nitrene precursor functional group is 5 to 30 mol% in the total monomers. The polymerization may be performed in On the other hand, when the copolymerization property of the monomer having a nitrene precursor functional group is low, it is necessary to charge an excessive amount of the monomer having a nitrene precursor functional group. It should be noted that other monomers may be copolymerized without departing from the effects of the present invention. There are no particular restrictions on the polymerization, and radical polymerization or ionic polymerization may be used, and any method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, dispersion polymerization, and precipitation polymerization may be used. Absent. From the viewpoint of ease of operation, radical polymerization, particularly free radical polymerization is preferably used.

  According to the present invention, a functional polymer layer is simply introduced on the surface of the porous membrane to give various functions to the porous membrane, such as hydrophilicity and wettability to the electrolyte solution, protein adsorption inhibition, biofau Prevention of ring generation, antithrombotic properties, biocompatibility, antistatic properties and the like can be imparted. In particular, by setting the thickness of the functional polymer layer to 5 to 100 nm and controlling the amount of the nitrene precursor component within a specific range, a high function can be expressed. Such characteristics are particularly useful in water treatment separation membranes and battery separators that require durability capable of maintaining high functionality for a long period of time, and can be widely used in this application field.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
(Production of functional polymer A having an azide group content of 9 mol%)
In a glass Schlenk flask, polyethylene glycol monomethyl ether methacrylate (manufactured by Aldrich, number average molecular weight 300, hereinafter abbreviated as PEGMA) (18 mmol) and methacryloyloxypropyloxy 4-phenylazide (2 mmol), 2,2′− as an initiator Azobisisobutyronitrile (AIBN) (0.09 mmol) was weighed. Monomers and initiators were dissolved using 25 ml of THF to prepare a uniform solution. After sufficiently removing oxygen in the solution with nitrogen, polymerization was carried out at 60 ° C. for 8 hours. After completion of the polymerization, unreacted monomers were removed by reprecipitation using hexane, followed by drying under reduced pressure to obtain a brown syrupy polymer. The obtained polymer had a number average molecular weight of 72,000, a weight average molecular weight of 253,000, and an azide group content of 9 mol%.

(Immobilization on the porous membrane surface)
A PVDF composite membrane (MV020 manufactured by Microdyne Nadia) using a polyester nonwoven fabric as a base material as a porous membrane was immersed in a 2% methanol solution of functional polymer A for 5 minutes. Then, it was made to dry at room temperature in nitrogen atmosphere, and then UV irradiation (100 mW / cm < ² >) was performed for 1 minute using LED (The main wavelength 365nm made from an ITEC system). Then, it wash | cleaned by irradiating an ultrasonic wave for 1 minute each in ultrapure water and methanol, and obtained the PVDF MF film | membrane which fix | immobilized the PEGMA copolymer on the surface. In order to calculate the thickness of the PEGMA copolymer layer on the membrane surface, the carbonyl absorption intensity derived from PEGMA copolymer (around 1730 cm ⁻¹ ) was normalized with the absorption intensity around 870 cm ⁻¹ derived from PVDF using ATR / FT-IR. When the strength was determined, the relative strength was 0.073. Moreover, the calibration curve was created by calculating the film thickness of the coating layer from the weight increase rate before and after coating and the specific surface area of the film, and plotting it against the carbonyl relative intensity. When this calibration curve was used to estimate the coating film thickness from the carbonyl relative intensity, the film thickness was 12 nm.

(Quantification of protein adsorption)
Insulin (manufactured by Wako Pure Chemical Industries) was used as a sample protein. The above surface-coated porous membrane is cut into 1 cm × 1 cm, immersed in an insulin solution (1 mg / mL, diluted with PBS), shaken at room temperature for 2 hours (80 rpm) to adsorb insulin, and then washed with PBS. did. The membrane was placed in a φ12 × 105 test tube, 1 mL of BCA reagent (manufactured by Thermo scientific) and 1 mL of 4 wt% PBS solution of sodium dodecyl sulfate were added and heated to 60 ° C. for 1 hour. Thereafter, the amount of insulin adsorbed on the membrane was quantified by measuring the absorbance at a wavelength of 562 nm using a spectrophotometer. The amount of insulin adsorbed was 0.7 μg / cm ² . Further, in order to evaluate the chemical resistance of the surface-modified porous membrane, the surface-modified porous membrane was immersed in a 1380 ppm sodium hypochlorite aqueous solution at room temperature for 7 days, and the amount of insulin adsorbed was measured by the same method. As a result, the amount of adsorbed insulin was 0.8 μg / cm ² , which was almost the same value as the amount of adsorbed before immersion, and thus the high resistance to hypochlorous acid of the surface coat layer could be confirmed. The results are summarized in Table 1.

Example 2
(Production of functional polymer B having azide group content of 7 mol%)
A glass Schlenk flask was charged with PEGMA (18 mmol), methacryloyloxypropyloxy 4-phenylazide (2 mmol) and 3 ml of acetone to obtain a homogeneous solution, and then oxygen was removed by nitrogen bubbling. Next, cuprous bromide (0.1 mmol), cupric bromide (0.025 mmol), bipyridyl (0.25 mmol), ethyl 2-bromoisobutyrate (0.1 mmol) were added, and at 50 ° C. Polymerization was carried out for 6 hours. After completion of the polymerization, unreacted monomers were removed by reprecipitation using hexane, copper was removed through a reduced pressure alumina column, and dried to obtain a brown syrupy polymer. The obtained polymer had a number average molecular weight of 33,000, a weight average molecular weight of 52,800, and an azide group content of 7 mol%.

(Immobilization on the porous membrane surface)
A PVDF MF membrane having the functional polymer B immobilized on the surface thereof was obtained in the same manner as in Example 1. The relative carbonyl strength was 0.0483, and the thickness of the coating layer was 8 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was 4.8 μg / cm ² . The results are summarized in Table 1.

Example 3
(Production of functional polymer C having azide group content of 6 mol%)
Using methacryloyloxyethyloxycarboxy 4-phenylazide instead of methacryloyloxypropyloxy 4-phenylazide as an azide group-containing monomer, and using pentamethyldiethylenetriamine (0.14 mmol) instead of bipyridyl as a ligand A functional polymer C was produced in the same manner as in Example 2 except that the polymerization time was changed from 6 hours to 3.5 hours. The obtained polymer had a number average molecular weight of 18,000, a weight average molecular weight of 37,800, and an azide group content of 6 mol%.

(Immobilization on the porous membrane surface)
A PVDF MF film in which the functional polymer C was immobilized on the surface was obtained by the same operation as in Example 1 except that the UV irradiation time was changed to 5 minutes. The relative strength of carbonyl was 0.051, and the thickness of the coating layer was 8 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was 4.8 μg / cm ² . The results are summarized in Table 1.

Example 4
(Production of functional polymer D having azide group content of 7 mol%)
The use of methacryloyloxyethyloxycarboxy 2,3,5,6-tetrafluoro-4-phenylazide instead of methacryloyloxypropyloxy 4-phenylazide as the azide group-containing monomer, and the polymerization time from 8 hours to 5 hours A functional polymer D was produced in the same manner as in Example 1 except for the change. The obtained polymer had a number average molecular weight of 27,000, a weight average molecular weight of 45,900, and an azide group content of 7 mol%.

(Immobilization on the porous membrane surface)
A PVDF MF film in which the functional polymer D was immobilized on the surface was obtained by the same operation as in Example 1 except that the UV irradiation time was changed to 5 minutes. The relative carbonyl strength was 0.055, and the thickness of the coating layer was 9 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was 2.2 μg / cm ² . The results are summarized in Table 1.

Example 5
(Production of functional polymer B having azide group content of 7 mol%)
Functional polymer B was produced in the same manner as in Example 2. The obtained polymer had a number average molecular weight of 33,000, a weight average molecular weight of 52,800, and an azide group content of 7 mol%.

(Immobilization on the porous membrane surface)
Except that PVDF UF membrane (fractional molecular weight 200,000) was used as the porous membrane instead of PVDF MF membrane, and that the immersion time of the porous membrane in the polymer solution was extended from 5 minutes to 30 minutes The functional polymer B was immobilized on the surface of the UF membrane in the same manner as in Example 1. The relative carbonyl strength was 0.085, and the film thickness of the coating layer was 14 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was less than 0.4 μg / cm ² . The results are summarized in Table 1.

Example 6
(Production of functional polymer E having azide group content of 9 mol%)
A functional polymer E was produced in the same manner as in Example 1 except that methacryloyloxybutyl 4-phenylazide was used in place of methacryloyloxypropyloxy 4-phenylazide as the azide group-containing monomer. The obtained polymer had a number average molecular weight of 61,000, a weight average molecular weight of 152,000, and an azide group content of 9 mol%.

(Immobilization on the porous membrane surface)
Functional polymer E was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1. The relative carbonyl strength was 0.091, and the film thickness of the coating layer was 15 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was less than 0.4 μg / cm ² . The results are summarized in Table 1.

Example 7
(Production of functional polymer F having azide group content of 6 mol%)
A functional polymer F is produced in the same manner as in Example 1 except that methoxyethyl acrylate (hereinafter abbreviated as MEA) is used instead of PEGMA, the polymerization temperature is changed to 50 ° C., and the polymerization time is changed to 4 hours. did. The obtained polymer had a number average molecular weight of 83,000, a weight average molecular weight of 206,000, and an azide group content of 6 mol%.

(Immobilization on the porous membrane surface)
The functional polymer F was immobilized on the PVDF MF membrane surface in the same manner as in Example 1 except that the immersion solvent for the porous membrane was changed from methanol to chloroform. The relative carbonyl strength was 0.26, and the film thickness of the coating layer was 42 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was less than 0.4 μg / cm ² . The results are summarized in Table 1.

Example 8
(Production of functional polymer G having an azide group content of 9 mol%)
A functional polymer G was produced in the same manner as in Example 1 except that polyethylene glycol methacrylate (manufactured by Aldrich, number average molecular weight 360, hereinafter abbreviated as PEGMA (OH)) was used instead of PEGMA. The obtained polymer had a number average molecular weight of 68,000, a weight average molecular weight of 170,000, and an azide group content of 9 mol%.

(Immobilization on the porous membrane surface)
The functional polymer G was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1. The relative carbonyl strength was 0.061, and the thickness of the coating layer was 10 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was less than 0.4 μg / cm ² . The results are summarized in Table 1.

Example 9
(Production of functional polymer H having an azide group content of 8 mol%)
Implemented except that 2-methacryloyloxyethyl phosphorylcholine (manufactured by Tokyo Chemical Industry, hereinafter abbreviated as MPC) was used instead of PEGMA, and an ethanol / dioxane (1/1) mixed solvent was used instead of THF. Functional polymer H was produced in the same manner as in Example 1. The obtained polymer had a number average molecular weight of 44,000, a weight average molecular weight of 115,000, and an azide group content of 8 mol%.

(Immobilization on the porous membrane surface)
The functional polymer H was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1. The relative carbonyl strength was 0.071, and the coating layer thickness was 12 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was less than 0.4 μg / cm ² . The results are summarized in Table 1.

Example 10
(Production of functional polymer B having azide group content of 7 mol%)
Functional polymer B was produced in the same manner as in Example 2. The obtained polymer had a number average molecular weight of 33,000, a weight average molecular weight of 52,800, and an azide group content of 7 mol%.

(Immobilization on the porous membrane surface)
Example 1 except that a chlorinated PVC MF membrane (MF-20V made by Yuasa Membrane System, nominal pore size 0.2 μm) using a polyester nonwoven fabric as the base material was used as the porous membrane instead of the PVDF MF membrane. The functional polymer B was immobilized on the surface of the MF membrane made of chlorinated PVC by the same operation as described above. The carbonyl relative intensity was normalized by the carbonyl absorption intensity (around 1730 cm ⁻¹ ) derived from the coat layer with the absorption intensity around 1250 cm ⁻¹ derived from chlorinated PVC. The relative strength obtained was 0.110, and the thickness of the coating layer was 22 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was less than 0.4 μg / cm ² . The results are summarized in Table 1.

Example 11
(Production of functional polymer I having azide group content of 9 mol%)
Functional polymer I was produced in the same manner as in Example 1 except that the number average molecular weight of polyethylene glycol monomethyl ether methacrylate was changed from 300 to 950. The obtained polymer had a number average molecular weight of 93,000, a weight average molecular weight of 279,000, and an azide group content of 9 mol%.

(Immobilization on membrane surface)
Functional polymer I was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1. The relative carbonyl strength was 0.086, and the film thickness of the coating layer was 14 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was less than 0.4 μg / cm ² . When hypochlorous acid resistance was evaluated under the same conditions as in Example 1, the amount of insulin adsorbed after immersion was less than 0.4 μg / cm ² .

Example 12
(Production of functional polymer B having azide group content of 7 mol%)
Functional polymer B was produced in the same manner as in Example 2. The obtained polymer had a number average molecular weight of 33,000, a weight average molecular weight of 52,800, and an azide group content of 7 mol%.

(Immobilization on the porous membrane surface)
A hollow fiber PVDF MF membrane module (UMP-053 manufactured by Asahi Kasei Chemicals Co., Ltd., nominal pore size 0.2 μm) was used instead of the PVDF MF membrane as the porous membrane, and a 2% methanol solution of the functional polymer B was added at 10 ml / min. And circulated for 5 minutes. Thereafter, the solution was switched to methanol and passed for 3 minutes, and nitrogen was blown to dry. Subsequently, UV irradiation was performed for 10 minutes at an irradiation intensity of 100 mW / cm ² using a high-pressure mercury lamp.

Thereafter, the membrane was washed with methanol and ultrapure water for 3 minutes each to obtain a PVDF MF membrane having a surface immobilized with a PEGMA copolymer. In order to calculate the thickness of the PEGMA copolymer layer on the membrane surface, the carbonyl absorption intensity derived from PEGMA copolymer (around 1730 cm ⁻¹ ) was normalized with the absorption intensity around 870 cm ⁻¹ derived from PVDF using ATR / FT-IR. When the strength was determined, the relative strength was 0.043. Moreover, the calibration curve was created by calculating the film thickness of the coating layer from the weight increase rate before and after coating and the specific surface area of the film, and plotting it against the carbonyl relative intensity. When this calibration curve was used to estimate the coating film thickness from the carbonyl relative intensity, the film thickness was 7 nm.

(Pressure change when passing protein solution)
A 1000 mg / L aqueous solution of bovine serum albumin was prepared and added to the PEGMA copolymer-immobilized MF membrane module at 100 nl / min. For 5 minutes, and the rise in the membrane inlet pressure from the beginning of the flow was measured. The increase in pressure was as small as 22 kPa, and it was considered that the increase in pressure was also suppressed because adsorption of protein to the membrane was suppressed.

Example 13
(Production of functional polymer A having an azide group content of 9 mol%)
A functional polymer A was produced in the same manner as in Example 1. The obtained polymer had a number average molecular weight of 72,000, a weight average molecular weight of 252,000, and an azide group content of 9 mol%.

(Immobilization on the porous membrane surface)
A PVDF MF membrane having the functional polymer A immobilized on the surface was obtained by the same operation as in Example 1. The relative carbonyl strength was 0.073, and the film thickness of the coating layer was 12 nm.

(Immersion test in activated sludge tank)
Using actual activated sludge, the fouling behavior of the membrane was evaluated. A small MBR tester (manufactured by Yuasa Membrane) was used as an evaluation device, and activated sludge was sampled from a dredging complex wastewater treatment facility, and the MLSS concentration was adjusted to 8000 mg / L and introduced into the tester. As the membrane element, the surface-modified MF membrane was attached to both surfaces of the mold by ultrasonic welding and set in a testing machine. The filtration flux is sucked with a tube pump so as to be 0.8 m ³ / m ² / Day, and 4 NL / min. It was continuously aerated with aeration of · m ^3. In this state, continuous operation was continued for one week, and the increase in the transmembrane pressure difference was measured. As a result, the increase in the transmembrane pressure difference was very small, 3 kPa, and fouling could be suppressed.

Comparative Example 1
As the PVDF MF membrane, the MF membrane (MV020, manufactured by Microdyne Nadia) having the same nominal pore diameter as that used in Example 1 was used to quantify the amount of protein adsorbed.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was 63 μg / cm ² , which was a larger value than in the Example.

Comparative Example 2
As the PVDF UF membrane, a protein adsorption amount was quantified using a UF membrane (UV200, manufactured by Microdyne Nadia) with a molecular weight cut-off of 200,000.
(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was 84 μg / cm ² , which was a larger value than in the Example.

Comparative Example 3
As an MF membrane made of chlorinated PVC, an amount of protein adsorbed was quantified using an MF membrane having a nominal pore diameter of 0.4 μm (MF-40B manufactured by Yuasa Membrane).
(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was 16 μg / cm ² , which was a larger value than in the Example.

Comparative Example 4
(Production of functional polymer J having an azide group content of 48 mol%)
A functional polymer I was produced in the same manner as in Example 1, except that 10 mmol each of PEGMA and methacryloyloxypropyloxy 4-phenylazide were used. The obtained polymer had a number average molecular weight of 30,000, a weight average molecular weight of 91,000, and an azide group content of 48 mol%.

(Immobilization on the porous membrane surface)
Functional polymer J was immobilized on the PVDF MF membrane surface in the same manner as in Example 1 except that the immersion solvent for the separated porous membrane was changed from methanol to chloroform. The relative carbonyl strength was 0.20, and the thickness of the coating layer was 35 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was 43 μg / cm ² . It can be seen that the amount of insulin adsorbed increases when the amount of the cross-linking component is outside the range of the present invention even if the coating layer is sufficiently thick. The results are summarized in Table 1.

Comparative Example 5
(Production of functional polymer B having azide group content of 7 mol%)
Functional polymer B was produced in the same manner as in Example 2. The obtained polymer had a number average molecular weight of 33,000, a weight average molecular weight of 52,800, and an azide group content of 7 mol%.
(Immobilization on the porous membrane surface)
The functional polymer B was immobilized on the PVDF MF membrane surface in the same manner as in Example 1 except that the methanol solution concentration of the functional polymer B was 0.5% and the immersion time was changed to 10 seconds. The relative strength of carbonyl was 0.011, and the thickness of the coating layer was 2 nm.

(Quantification of protein adsorption)
When the amount of insulin adsorbed on the membrane was quantified by the same operation as in Example 1, it was 50 μg / cm ² . It can be seen that when the coating layer is thin, the amount of insulin adsorption increases. The results are summarized in Table 1.

Comparative Example 6
(Pressure change when passing protein solution)
An unmodified hollow fiber PVDF MF membrane module (UMP-053 manufactured by Asahi Kasei Chemicals Co., Ltd., nominal pore size 0.2 μm) was added with bovine serum albumin 1000 mg / L aqueous solution at 100 nl / min. For 5 minutes, and the rise in the membrane inlet pressure from the beginning of the flow was measured. The pressure increase was 60 kPa, which was a large value compared to Example 12. It is thought that the increase in pressure increased due to the large amount of protein adsorbed on the membrane.

Comparative Example 7
As the PVDF MF membrane, the same MF membrane having a nominal pore diameter of 0.2 μm as used in Example 1 (MV020 manufactured by Microdyne Nadia) was used to perform an immersion test in an activated sludge tank.
(Immersion test in activated sludge tank)
When the increase in transmembrane pressure difference was measured by the same method as in Example 13, the increase in transmembrane pressure pressure reached 45 kPa, confirming the progress of fouling.

Claims (7)

It consists of a porous membrane and a functional polymer layer formed on the surface of the porous membrane through a covalent bond, and the functional polymer layer is generated by a reaction between a functional component containing a hydrophilic group and a porous membrane and nitrene. A surface-modified porous membrane containing a cross-linking component, wherein the functional polymer layer contains 5 to 30 mol% of a cross-linking component, and the functional polymer layer has a thickness of 5 to 100 nm. Modified porous membrane. A polymer of a monomer in which the functional component introduced into the functional polymer layer has a functional group selected from an alkoxyalkyl group, a monoalkoxypolyoxyethylene group, a polyoxyethylene group or a betaine group, and a vinyl group The surface-modified porous membrane according to claim 1, wherein The surface-modified porous membrane according to claim 1 or 2, wherein the cross-linking component introduced into the functional polymer layer is a polymer of a monomer having a nitrene precursor functional group and a vinyl group. The surface-modified film according to any one of claims 1 to 3, wherein the component introduced into the functional polymer layer is a polymer having a structure represented by the general formula (1).
(In the formula, m and n independently represent an integer of 1 or more, X represents a phenylene group which may have a substituent, or a group represented by an ester bond or an amide bond, and Y represents a betaine group. Represents a hydrophilic group selected from an alkoxyalkyl group, an alkoxypolyoxyethylene group, and a hydroxypolyoxyethylene group, Z represents a group represented by —O— or —N (R ₃ ) —, and A represents —O -Or -CH _2- represents a group, R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a C ₁ -C ₆ hydrocarbon group, and R ₄ is a C ₃ -C ₆ Represents a divalent hydrocarbon group, R ₅ represents a fluorine atom, and p represents an integer of 0 to 4.)

The surface-modified porous membrane according to any one of claims 1 to 4, which is used in a membrane separation activated sludge method. A water treatment separation membrane comprising the surface-modified porous membrane according to any one of claims 1 to 5. A functional polymer composed of a functional component and a component having a nitrene precursor functional group of 5 to 30 mol% is present on the porous membrane surface, and the functional polymer layer is formed on the porous membrane surface via a covalent bond by light irradiation. The method for producing a surface-modified porous film according to claim 1, wherein the method is formed.