JP6855797B2 - Surface-modified porous membrane and its manufacturing method - Google Patents

Description

The present invention relates to a surface-modified porous membrane and a method for producing the same. By using the present invention, the surfaces of microfiltration membranes, ultrafiltration membranes, battery separators and other porous membranes used in the fields of water treatment and separation and purification of foods and pharmaceuticals are easily modified to impart functions. be able to.

As a method for modifying the surface of a porous membrane, a method of coating the membrane surface with a functional polymer, a method of blending a functional polymer with a membrane material and then forming a porous membrane, a method of treating with plasma or corona, and a method of treating the membrane surface. A method of introducing a polymerization initiating group into the membrane and performing graft polymerization has been proposed. 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 is difficult to maintain the function stably for a long period of time. The method of blending the functional polymer with the membrane material and then forming the membrane into the separated porous membrane is a simple method that does not require special equipment, but the functional polymer is required to sufficiently coat the membrane surface with the functional polymer. The amount to be added must be considerably increased, which tends to cause a decrease in the mechanical properties of the film and a decrease in chemical resistance, and further, an increase in cost due to a large amount of addition of a functional polymer becomes a problem. On the other hand, the plasma treatment and corona treatment methods require a large-scale device, and have a drawback that the base material is easily damaged during the treatment process. 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 does not damage the base material, but the method of introducing a polymerization initiating group differs depending on the type of the base material, which 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 the surface of a substrate using a nitrene insertion reaction as a method for improving the drawbacks of the conventional modification method. This method is an excellent method in that the functional polymer can be introduced into the surface of the substrate via a covalent bond by a simple method such as coating of the functional polymer and UV irradiation. However, probably because the insertion reaction of nitrene is consumed not only for the reaction with the base material at the base material interface but also for the internal cross-linking of the functional polymer, there are many introduced and immobilized functional polymers. Nevertheless, there were cases 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.

Special Table No. 3-505979 Japanese Unexamined Patent Publication No. 2010-59346

An object of the present invention is to manufacture and provide a surface-modified porous membrane having excellent durability as well as simply introducing a functional polymer layer onto the surface of the porous membrane to impart functions.

In order to achieve the above object, as a result of diligent studies by the present inventors, a functional component containing an electrically neutral (apparently uncharged) hydrophilic group in the functional polymer layer is selected. By introducing a component having a nitrene precursor functional group in a specific ratio and forming a functional polymer layer on the surface of the porous film with a thickness of 5 to 100 nm, the surface-modified porous film has high functionality and durability. We have found that it is possible to impart sex, and have completed the present invention.

That is, the present invention
[1] It is composed 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 composed of a functional component containing a hydrophilic group and the porous membrane and nitrene. A surface-modified porous membrane containing a cross-linking component generated by the reaction, wherein the functional polymer layer contains 5 to 30 mol% of the cross-linking component, and the thickness of the functional polymer layer is 5 to 100 nm. Surface-modified porous membrane.
[2] A monomer having a functional group selected from an alkoxyalkyl group, a monoalkoxypolyoxyethylene group, a polyoxyethylene group or a betaine group, and a vinyl group as the functional component introduced into the functional polymer layer. The surface-modified porous film according to [1], which is a polymer of.
[3] The surface according to [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. 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 represent integers of 1 or more independently of each other, 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. , alkoxyalkyl group, alkoxy polyoxyethylene group, a hydrophilic group selected from hydroxy polyoxyethylene group, Z is -O- or -N (R 3) _- represents a group represented by, a is -O Representing a group represented by − or −CH _{2− , R 1} , R ₂ and R ₃ independently represent a hydrogen atom or a hydrocarbon group of _{C 1 to} C _{6 , and R 4} represents a group of C _{3 to} C ₆ . It represents a divalent hydrocarbon group, R ₅ represents a fluorine atom, and p represents an integer of 0-4.)

［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 the 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 5 to 30 mol% nitrene precursor functional group is present on the surface of the porous membrane, and is functionally exposed to the surface of the porous membrane via a covalent bond. A method for producing a surface-modified porous film according to any one of [1] to [4], which comprises forming a polymer layer.

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 surface of the membrane.

The material of the porous membrane used in the present invention is not particularly limited, but it is necessary to have a site that reacts with nitrene generated by UV irradiation of the functional polymer. The sites that react with nitrene refer to carbon-hydrogen bonds and nitrogen-hydrogen bonds, and are metals such as aluminum, iron, stainless steel, titanium, gold, platinum, silver, and copper, silica, alumina, zirconia, titania, silicon nitride, and 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 membrane made of an organic polymer, such a need is not necessary and it can be used as it is. Some examples of organic polymers include polyethylene, chlorinated polyethylene, polypropylene, polyvinyl chloride, chlorinated polyvinylidene 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, non-existent Saturated polyester and the like can be mentioned.

Examples of the shape of the porous membrane include a flat membrane-like porous membrane and a hollow filamentous 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 referred to here is a porous membrane having a pore size of about 0.05 to 10 μm, and is made of polyethylene, polypropylene, polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene fluoride, or polytetrafluoroethylene. , Polyacrylonitrile, polycarbonate, polysulfone, organic polymers such as 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 is made of polyethylene, polyacrylonitrile, polyvinyl chloride, polyvinyl chloride-polyacrylonitrile copolymer, polysulfone, polyethersulfone, etc. Organic polymers such as polyvinylidene fluoride, aromatic polyamide, polyimide and cellulose acetate and ceramics such as alumina are used.

While microfiltration membranes often have a uniform porous structure, ultrafiltration membranes have an asymmetric membrane structure in which the porous layer on the surface and the support layer inside have different porous structures. There is. Further, a composite film in which two or more kinds of materials are composited 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 porous layer are composited is preferably used. The base material used for reinforcement referred to here is organic fibers such as polyester fibers, nylon fibers, polyurethane fibers, acrylic fibers, rayon fibers, cotton and silk, their textiles, knitted fabrics, non-woven fabrics, etc., glass fibers and metal fibers. Examples thereof include inorganic fibers such as, and their woven fabrics and knitted fabrics. Some examples of composite membranes include flat membrane microfiltration membranes in which a polyester non-woven membrane is combined with a porous membrane made of polyether sulfone, and flat membrane microfiltration membranes in which a polyester non-woven membrane is combined with a porous membrane made of polyvinylidene fluoride. Examples thereof include a hollow filament microfiltration membrane in which a polyester braid is combined with a porous membrane made of polyvinylidene fluoride.

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

The film thickness of the porous film is not particularly limited as long as the 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 on the surface of a porous film via a covalent bond, and has a function of containing an electrically neutral (apparently uncharged) hydrophilic group. It is composed of a functional component having a sex component such as an alkoxyalkyl group, a monoalkoxypolyoxyethylene group, a polyoxyethylene group, and a betaine group, and a cross-linking component generated by the reaction of nitrene. Specific examples of the alkoxyalkyl group which is a functional component include a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, an ethoxyethyl group and the like.

Specific examples of the monoalkoxypolyoxyethylene group include 2- (2-methoxyethoxy) ethyl group, 2- (2-ethoxyethoxy) ethyl group, and 2- {2- (2-methoxyethoxy) ethoxy} ethyl. Examples thereof include a group, a methoxypolyoxyethylene group, an ethoxypolyoxyethylene group, and specific examples of the polyoxyethylene group include a 2- (2-hydroxyethoxy) ethyl group and a 2- {2- (2-hydroxyethoxy) group. Examples thereof include an ethoxy} ethyl group and an ω-hydroxypolyoxyethylene group.

A betaine group has a positively charged portion and a negatively charged portion in the same group at non-adjacent positions in the ionized state, and a dissociable hydrogen atom is bonded to the positively charged atom. It refers to a group that is not 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 "functional component" has a porous function such as imparting hydrophilicity or wettability to an electrolyte solution, suppressing protein adsorption, preventing the occurrence of biofouling, antithrombotic property, biocompatibility, and antistatic property. It is a component to be applied to the membrane and contains an electrically neutral (apparently uncharged) hydrophilic group.

In the present invention, the "crosslinking component" means that a component having a nitrene precursor functional group produces nitrene by light irradiation, and the nitrene is inserted into a carbon-hydrogen bond or a nitrogen-hydrogen bond to crosslink and form a covalent bond. It is an ingredient. It is important that this cross-linking component is contained in the functional polymer in a proportion 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%, the functional polymer layer is insufficiently immobilized on the surface of the porous membrane, which is not preferable. On the other hand, if it exceeds 30 mol%, protein adsorption is suppressed and biofouling is performed. It is not preferable because it causes deterioration of functions such as prevention of occurrence of blood clots and antithrombotic properties.

In the present invention, the "functional polymer layer" refers to a polymer layer composed of the "functional component" and the "crosslinking component" and formed on the surface of a porous membrane through covalent bonds. By forming the functional polymer layer on the surface of the porous membrane, various functions derived from the functional components can be immobilized and introduced on the surface of the porous membrane.

The thickness of the functional polymer layer formed on the surface of the porous membrane is 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, not only further high functionality cannot be expected, but also the pores of the porous film may be clogged, which is not preferable. When the thickness of the polymer layer is less than 10 nm, the functions such as imparting hydrophilicity and wettability to the electrolyte solution, suppressing protein adsorption, preventing the occurrence of biofouling, antithrombotic property, biocompatibility, and antistatic property are exhibited. Although it develops, it may be inferior in durability when used for a long period of time under harsh conditions. On the other hand, when the thickness is 10 nm or more, the durability is enhanced, and the deterioration of the function can be suppressed even if it is used for a long time under harsh conditions.

In particular, the porous membrane used in the membrane separation active sludge method (hereinafter abbreviated as MBR) is very easy to get dirty, and it is harsh such as repeating washing with a high concentration sodium hypochlorite aqueous solution to prevent membrane clogging. Although it is used under various conditions, even in such an application, the function can be maintained for a long period of time by setting the thickness of the functional polymer layer to 10 to 100 nm.

The method for producing a surface-modified porous membrane of 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 through covalent bonds by light irradiation. ..

The method for allowing the functional polymer to exist on the surface of the porous membrane is not particularly limited, and a method of coating the porous membrane with the functional polymer as it is or by diluting it with a solvent can be used. The coating method is also 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, it is irradiated with light. The light needs to be light having a wavelength at which the photoreactive group used can generate nitrene, and when an azide group is used as the photoreactive group, it irradiates ultraviolet rays having a wavelength of 10 to 400 nm, preferably around 250 to 380 nm. .. The intensity of the ultraviolet rays to be irradiated is not particularly limited, but can be appropriately selected in the range of 1 to ^{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 at the time of coating and mechanical strength of the polymer layer, 5,000 to 500, The range of 000 is preferable. The functional polymer is a copolymer of a functional component and a cross-linking component, but they may be arranged in a random manner or in a block shape. Further, although the functional polymer is soluble in water, it may be water-soluble or water-insoluble. For example, if the functional component is water-soluble and the proportion of the cross-linking component is low, it becomes water-soluble, but if the functional component is insoluble in water and the proportion of the cross-linking component is high, it is insoluble in water.

Functional groups and vinyl groups selected from an alkoxyalkyl group, a monoalkoxypolyoxyethylene group, a polyoxyethylene group, a sulfobetaine group, a carbobetaine group, and a phosphobetaine group as functional components constituting the functional polymer of the present invention. A polymer of a monomer having and can be used. Examples of the vinyl group include a methacryloxy group, a methacrylicamide group, an acrylicoxy group, an acrylamide group, a styryl group, etc., and methacrylicoxy in terms of high mechanical strength of the polymer and excellent affinity with a porous film. A group and an acrylic oxy group are preferable.

Specific examples of the above monomers include methoxyethyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, methoxyethyl acrylamide, 2-methoxyethoxystyrene, 2- (2-methoxyethoxy) ethyl methacrylate, and 2- (2-methoxyethoxy). Ethyl acrylate, 2- (2-methoxyethoxy) ethyl methacrylate, 2- (2-methoxyethoxy) ethyl acrylamide, 2- (2-methoxyethoxy) ethoxystyrene, polyethylene glycol methyl ether methacrylate, polyethylene glycol methyl ether acrylate, polyethylene Glycolmethyl ether methacrylicamide, polyethylene glycol methyl ether acrylamide, polyethylene glycol ethyl ether methacrylate, polyethylene glycol ethyl ether acrylate, polyethylene glycol ethyl ether methacrylicamide, polyethylene glycol ethyl ether acrylamide, 2- (2-hydroxyethoxy) ethyl methacrylate, 2- (2-Hydroxyethoxy) ethyl acrylate, 2- (2-hydroxyethoxy) ethylmethacrylate, 2- (2-hydroxyethoxy) ethylacrylamide, 2- (2-hydroxyethoxy) ethoxystyrene, polyethylene glycol monomethacrylate, polyethylene glycol Monoacrylate, polyethylene glycol monomethacrylicamide, polyethylene glycol monoacrylamide, N-methacryloyl-L-histidine, 2-methacryloyloxyethyl phosphorylcholine, 2- (N-3-sulfopropyl-N, N-dimethylammonium) ethyl methacrylate, 2 -(N-Carbomethoxy-N, N-dimethylammonium) ethyl methacrylate and the like can be mentioned.

As the cross-linking 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, an aryl azide such as phenyl azide or tetrafluorophenyl azide; an acyl azide such as benzoyl azide methyl benzoyl azide; an azide format such as ethyl azide format or phenyl azido format; Examples thereof include sulfonyl azides such as benzene sulfonyl azide, but aryl azide is preferably used. Examples of the vinyl group include a methacryloxy group, a methacrylicamide group, an acrylicoxy group, an acrylamide group, a styryl group and the like, but when the functional component is a polymer of a monomer having a methacrylicoxy group or an acrylicoxy group, both are used. A methacryloxy group or an acrylicoxy group is preferable from the viewpoint of enhancing the polymerizable property.

Specific examples of the above monomers include methacryloyloxypropyloxy4-phenyl azide, acryloyloxypropyloxy4-phenyl azide, methacrylamidopropyloxy 4-phenyl azide, acrylamide propyloxy 4-phenyl azide, and methacryloyl oxyethyl oxy 4-phenyl. Azide, acryloyloxyethyloxy4-phenyl azide, methacrylamide ethyloxy4-phenyl azide, acrylamide ethyloxy4-phenyl azide, methacryloyloxyethyloxycarboxy4-phenyl azide, acryloyloxyethyloxycarboxy4-phenyl azide, methacrylamide Ethyloxycarboxy4-phenyl azide, acrylamide ethyloxycarboxy4-phenyl azide, methacryloyloxyethyl 4-phenyl azide, acryloyloxyethyl 4-phenyl azide, methacrylamidoethyl 4-phenyl azide, acrylamide ethyl 4-phenyl azide, methacryloyloxy Propyl4-phenyl azide, acryloyloxypropyl 4-phenyl azide, methacrylamidopropyl 4-phenyl azide, acrylamide propyl 4-phenyl azide, methacryloyl oxybutyl 4-phenyl azide, acryloyl oxybutyl 4-phenyl azide, methacrylamid butyl 4- Phenyl azide, acrylamide butyl 4-phenyl azide, methacryloyloxyethyl oxycarboxy 2,3,5,6-tetrafluoro-4-phenyl azide, acryloyl oxyethyl oxycarboxy 2,3,5,6-tetrafluoro-4-phenyl Azide, Methacrylate ethyloxycarboxy 2,3,5,6-Tetrafluoro-4-phenyl azide, Acrylethyloxycarboxy 2,3,5,6-Tetrafluoro-4-phenyl azide, Methacryloyloxypropyloxy 2,3 , 5,6-Tetrafluoro-4-phenyl azide, acryloyloxypropyloxy 2,3,5,6-tetrafluoro-4-phenyl azide, methacrylamidopropyloxy 2,3,5,6-tetrafluoro-4- Phenyl azide, acrylamide propyloxy 2,3,5,6-tetrafluoro-4-phenyl azide, methacrylicamide 4-phenyl azide, acrylamide 4-phenyl azide, methacrylicamide 2,3,5,6-tetrafluo Examples thereof include ro-4-phenyl azide and acrylamide 2,3,5,6-tetrafluoro-4-phenyl azide.

The functional polymer used in the present invention is a copolymer of the above-exemplified monomers, 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 represent integers of 1 or more independently of each other, 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. , alkoxyalkyl group, alkoxy polyoxyethylene group, a hydrophilic group selected from hydroxy polyoxyethylene group, Z is -O- or -N (R 3) _- represents a group represented by, a is -O Representing a group represented by − or −CH _{2− , R 1} , R ₂ and R ₃ independently represent a hydrogen atom or a hydrocarbon group of _{C 1 to} C _{6 , and R 4} represents a group of C _{3 to} C ₆ . It represents a divalent hydrocarbon group, R ₅ represents a fluorine atom, and p represents an integer of 0-4.)
The substituent of the phenylene group which may have a substituent represented by X is not particularly limited, but is limited to 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 are exemplified. As X, an ester bond is preferable.

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, "betaine" means hydrogen that has a positively charged portion and a negatively charged portion in the same group at non-adjacent positions in the ionized state and can be dissociated into a positively charged atom. It is assumed that the atoms are not bonded and are neutral (have no charge) as a whole. 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. The alkoxyalkyl group is not particularly limited, and examples thereof include a 2-methoxyethyl group, a 3-methoxypropyl group, and a 4-methoxybutyl group. The alkoxypolyoxyethylene group is not particularly limited, and examples thereof include a methoxypolyoxyethylene group, an ethoxypolyoxyethylene group, a normal propoxypolyoxyethylene group, and an isopropoxypolyoxyethylene group, and methoxypoly in terms of hydrophilicity. An oxyethylene group is preferred.

_{The hydrocarbon group of C 1 to} C ₆ represented by R ₁ , R ₂ and R ₃ is not particularly limited, but is a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopropyl group, a butyl group, an isobutyl group, and the like. 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 thereof include 4-methylpentyl group, 1-ethylbutyl group, 2-ethylbutyl group, cyclohexyl group and phenyl group.

The _{divalent hydrocarbon group of C 3 to} C ₆ represented by _{R 4} is not particularly limited, but-(CH ₂ ) ₃ -,-(CH ₂ ) ₄ -,-(CH ₂ ) ₅ -,-. (CH ₂ ) ₆ −, phenylene group and the like are exemplified. When the number of carbon atoms of the divalent hydrocarbon group represented by R ₄ is 2 or less, or the glass transition temperature of the photoreactive polymer is lowered molecular mobility of elevated side chains, nitrenes generated from azide group Is consumed in the cross-linking reaction between the photoreactive polymers rather than the reaction with the base material, and the immobilization rate of the photoreactive polymer on the surface of the base material is lowered, which is not preferable. On the other hand, when the _{number of carbon atoms of the divalent hydrocarbon group represented by R 4} exceeds 6, the concentration of azide groups in the photoreactive polymer decreases, the number of cross-linking points decreases, and the photoreactive polymer on the surface of the substrate is used. It is not preferable because the immobilization rate is lowered.

In the photoreactive polymer having the structure represented by the general formula (1), m and n represent integers of 1 or more independently of each other. Here, the value of m / (m + n) is preferably 0.02 to 0.7, more preferably 0.05 to 0.5. Within this range, it is excellent in terms of both adhesion to the substrate and the effect of suppressing protein adsorption.

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。

(In the formula, R ₁ , X, Y and n have the same meanings as described above.) The structural unit represented by is not particularly limited, but is 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 Structural units derived from monomers such as ethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine are exemplified, and from the viewpoint of protein adsorption inhibitory effect, polyethylene glycol methyl ether methacrylate and 2-methacryloyloxyethyl phosphorylcholine, [ Structural units derived from 2- (methacryloyloxy) ethyl] dimethyl- (3-sulfopropyl) ammonium hydroxide, N-methacryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine are 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。

(In the formula, R ₂ , R ₄ , R ₅ , A, Z, m and p have the same meanings as described above.) The structural unit represented by is not particularly limited, but is 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) propylmethacrylate, 3- (4-azido-2,3,5,6-tetrafluorophenoxy) propylmethacrylate, 3 Structural units derived from monomers such as − (4-azidophenoxy) propylacrylamide, 4- (4-azidophenyl) butylmethacrylate, 4- (4-azidophenyl) butylacrylamide are exemplified, and the photodegradation rate of azide is illustrated. From the point of view, structural units derived from 3- (4-azidophenoxy) propyl methacrylate are preferred.

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 in any order of random, block, and alternate.

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, and the viscosity and solubility at the time of coating and the mechanical strength of the polymer layer can be selected. From the viewpoint of, the range of 10,000 to 500,000 is preferable. 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 is, for example, adhesiveness to a hydrophobic substrate. From the viewpoint of the stability of the coating film and the coating film, it is preferably about 1 to 5.

The photoreactive polymer having the structure represented by the general formula (1) may have a structural unit derived from another monomer as long as the effect of the present invention is not deviated. The structural unit derived from other monomers is not particularly limited, but is limited to polystyrene, poly (α-methylstyrene), polyvinylbenzyl chloride, polyvinylaniline, sodium polystyrenesulfonate, polyvinylbenzoic acid, polyvinylphosphate, polyvinylpyridine, polydimethyl. Sterite 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 ester such as polyvinyl acetate and vinyl polypropionate and polyvinyl alcohol which is a saponification thereof; nitrile polymer such as polyacrylonitrile; polymethacrylic acid, polyperfluoroalkyl methacrylate, ethyl polyacrylate, polyacrylic acid, polydimethyl (Meta) acrylic polymers such as aminoethyl acrylate; (meth) acrylamide polymers such as polyacrylamide, polymethacrylate, polydimethylaminopropylacrylamide, etc. are exemplified.

Examples of the photoreactive polymer of the present invention include those that are photoreactive polymers 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 meanings as described above.)
The value of r is preferably an integer in the range of 2 to 20 from the viewpoint of easiness of polymerization. R ₄ is preferably − (CH ₂ ) ₃ − or − (CH ₂ ) ₄ −, and more preferably − (CH ₂ ) ₃ −.

The photoreactive polymer having the structure represented by the above 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. It has hydrophilic groups such as phosphorylcholine, [2- (methacryloyloxy) ethyl] dimethyl- (3-sulfopropyl) ammonium hydroxide, N-methacryloyloxyethyl-N, N-dimethylammonium-α-N-methylcarboxybetaine, etc. Monomers and 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) propyl methacrylate, 3- (4-azido-2,3,5,6 -Has photoreactive groups such as tetrafluorophenoxy) propylmethacrylate, 3- (4-azidophenoxy) propylacrylamide, 4- (4-azidophenyl) butylmethacrylate, 4- (4-azidophenyl) butylacrylamide, etc. Use monomer.

The polymerization is not particularly limited, and for example, radical polymerization, ionic polymerization, and coordination polymerization are exemplified, and radical polymerization, particularly free radical polymerization or living radical polymerization is preferably used from the viewpoint of ease of operation. The polymerization initiator is not particularly limited, and is, for example, 2,2'-azobisisobutyronitrile (AIBN), benzoyl peroxide, diisopropylperoxydicarbonate, tert-butylperoxy-2-ethylhexanoate, tert. Known radical initiators such as -butylperoxypivalate, tert-butylperoxydiisobutyrate, persulfate or persulfate-hydrogen sulfite can be used. As the polymerization solvent, for example, known radical polymerization solvents such as water, THF, dioxane, acetone, 2-butanone, ethyl acetate, isopropyl acetate, benzene, toluene, DMF, DMSO, methanol, ethanol, isopropanol and a mixture thereof are used. For example, it can be produced by diluting it so that the monomer concentration is 0.01 to 5 mol / L and the polymerization initiator concentration is 1 to 100 mmol / L, and carrying out the reaction at 0 to 80 ° C. for 1 to 72 hours. .. The polymerization form is not particularly limited, and examples thereof include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, dispersion polymerization, and precipitation polymerization, and solution polymerization is preferably used because of the ease of operation.

Examples of the functional polymer represented by the general formula (1) include polyethylene glycol methyl ether methacrylate / methacryloyloxypropyloxy4-phenylazide copolymer and 2-methacryloyloxyethyl phosphorylcholine / methacryloyloxypropyloxy4-phenylazide. Polymer, 2- (N-3-sulfopropyl-N, N-dimethylammonium) ethyl methacrylate / methacryloyloxypropyloxy4-phenylazide copolymer, 2- (N-carbomethoxy-N, N-dimethylammonium) Ethyl methacrylate / methacryloyloxypropyloxy4-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 / methacryloyl Examples thereof include an oxybutyl 4-phenylazide copolymer and the like.

When the copolymerization of the monomer constituting the functional component and the monomer having the nitren precursor functional group is good, the charging ratio of the monomer is such that the monomer having the nitren precursor functional group is 5 to 30 mol% in the total monomer. It may be charged in and polymerized. On the other hand, when the copolymerizability of the monomer having a nitrene precursor functional group is low, it is necessary to charge an excess amount of the monomer having a nitrene precursor functional group. Other monomers may be copolymerized as long as the effects of the present invention are not deviated. The polymerization is not particularly limited, and radical polymerization or ionic polymerization may be used, or any method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, dispersion polymerization, or 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 easily introduced on the surface of a porous film to impart various functions to the porous film, for example, imparting hydrophilicity or wettability to an electrolyte solution, suppressing protein adsorption, and biofau. It is possible to impart ring generation prevention, antithrombotic property, biocompatibility, antistatic property, and the like. 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, high functionality can be exhibited. Such characteristics are particularly useful in water treatment separation membranes and battery separators that are required to have durability that can maintain high functionality for a long period of time, and can be widely used in this field of application.

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 with Azide Group Content of 9 Mol%)
Polyethylene glycol monomethyl ether methacrylate (made by Aldrich, number average molecular weight 300, hereinafter abbreviated as PEGMA) (18 mmol) and methacryloyloxypropyloxy4-phenyl azide (2 mmol) in a glass Schlenk flask, 2,2'-as an initiator. Azobisisobutyronitrile (AIBN) (0.09 mmol) was weighed. The monomer and initiator were dissolved using 25 ml of THF to prepare a homogeneous 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 a reprecipitation method using hexane and dried under reduced pressure to obtain a brown starch syrup-like 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 surface of porous membrane)
A PVDF composite membrane (MV020 manufactured by Microdyne Nadia) having a nominal pore size of 0.2 μm using a polyester non-woven fabric as a substrate was used as the porous membrane, and the functional polymer A was immersed in a 2% methanol solution for 5 minutes. Then, it was dried at room temperature under a nitrogen atmosphere, and then UV irradiation (100 mW / cm ² ) was performed for 1 minute using an LED (main wavelength 365 nm manufactured by Aitec System). Then, it was washed by irradiating ultrasonic waves in ultrapure water and methanol for 1 minute each to obtain a PVDF MF membrane having a PEGMA copolymer immobilized on the surface. To calculate the thickness of PEGMA copolymer layer of the film surface, the relative normalized PEGMA copolymer derived from carbonyl absorption intensity (1730 cm ^-1 before and after) in the absorption intensity of 870 cm ^-1 before and after from PVDF using ATR / FT-IR When the strength was determined, the relative strength was 0.073. In addition, a 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 relative carbonyl strength. When the coating film thickness was estimated from the carbonyl relative strength using this calibration curve, the film thickness was 12 nm.

(Quantification of protein adsorption amount)
Insulin (manufactured by Wako Junyaku) 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 the mixture was heated to 60 ° C. for 1 hour. Then, the amount of insulin adsorbed on the membrane was quantified by measuring the absorbance at a wavelength of 562 nm using a spectrophotometer, and 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 insulin adsorption amount was 0.8 μg / cm ² , which was almost the same value as the adsorption amount before immersion, and thus it was possible to confirm the high hypochlorous acid resistance of the surface coat layer. The results are summarized in Table 1.

Example 2
(Production of functional polymer B having an azide group content of 7 mol%)
PEGMA (18 mmol), methacryloyloxypropyloxy4-phenyl azide (2 mmol), and 3 ml of acetone were placed in a glass Schlenk flask to prepare a uniform solution, and then oxygen was removed by nitrogen bubbling. Then cuprous bromide (0.1 mmol), cupric bromide (0.025 mmol), bipyridyl (0.25 mmol) and ethyl 2-bromoisobutyrate (0.1 mmol) were added and at 50 ° C. The polymerization was carried out for 6 hours. After completion of the polymerization, unreacted monomers were removed by a reprecipitation method using hexane, copper was removed through a reduced pressure alumina column, and then dried to obtain a brown water candy-like 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 surface of porous membrane)
A PVDF MF membrane having the functional polymer B immobilized on the surface was obtained by the same operation as in Example 1. The relative strength of the carbonyl was 0.0483, and the film thickness of the coating layer was 8 nm.

(Quantification of protein adsorption amount)
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 the 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 an azide group content of 6 mol%)
Methacryloyloxyethyloxycarboxy4-phenyl azide was used instead of methacryloyloxypropyloxy4-phenyl azide as the azide group-containing monomer, and pentamethyldiethylenetriamine (0.14 mmol) was used instead of bipyridyl as the ligand. The 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 surface of porous membrane)
A PVDF MF membrane having the functional polymer C 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 0.051 and the film thickness of the coating layer was 8 nm.

(Quantification of protein adsorption amount)
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 the 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 with Azide Group Content of 7 Mol%)
Using methacryloyloxyethyloxycarboxydo 2,3,5,6-tetrafluoro-4-phenyl azide instead of methacryloyloxypropyloxy4-phenyl azide as the azide group-containing monomer, the polymerization time was reduced from 8 hours to 5 hours. Functional polymer D was produced in the same manner as in Example 1 except that it was modified. 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 surface of porous membrane)
A PVDF MF membrane having the functional polymer D 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 the carbonyl was 0.055, and the film thickness of the coating layer was 9 nm.

(Quantification of protein adsorption amount)
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 the 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 an 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 surface of porous membrane)
Except for the fact that PVDF UF membrane (fractional molecular weight 200,000) was used instead of PVDF MF membrane as the porous 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 by the same operation as in Example 1. The relative strength of the carbonyl was 0.085, and the film thickness of the coating layer was 14 nm.

(Quantification of protein adsorption amount)
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 the 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 an azide group content of 9 mol%)
Functional polymer E was produced in the same manner as in Example 1 except that methacryloyloxybutyl 4-phenyl azide was used instead of methacryloyloxypropyloxy4-phenyl azide 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 surface of porous membrane)
The functional polymer E was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1. The relative strength of the carbonyl was 0.091, and the film thickness of the coating layer was 15 nm.

(Quantification of protein adsorption amount)
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 the 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 an azide group content of 6 mol%)
Functional polymer F was produced in the same manner as in Example 1 except that methoxyethyl acrylate (hereinafter abbreviated as MEA) was used instead of PEGMA, the polymerization temperature was changed to 50 ° C., and the polymerization time was 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 surface of porous membrane)
The functional polymer F was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1 except that the immersion solvent of the porous membrane was changed from methanol to chloroform. The relative strength of the carbonyl was 0.26, and the film thickness of the coating layer was 42 nm.

(Quantification of protein adsorption amount)
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 the 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 with Azide Group Content of 9 Mol%)
The functional polymer G was produced in the same manner as in Example 1 except that polyethylene glycol methacrylate (manufactured by Aldrich, having a number average molecular weight of 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 surface of porous membrane)
The functional polymer G was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1. The relative strength of the carbonyl was 0.061, and the film thickness of the coating layer was 10 nm.

(Quantification of protein adsorption amount)
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 the 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 with Azide Group Content of 8 Mol%)
Performed except that 2-methacryloyloxyethyl phosphorylcholine (manufactured by Tokyo Kasei Co., Ltd., 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 surface of porous membrane)
The functional polymer H was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1. The relative strength of the carbonyl was 0.071, and the film thickness of the coating layer was 12 nm.

(Quantification of protein adsorption amount)
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 the 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 an 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 surface of porous membrane)
Example 1 except that a chlorinated PVC MF membrane (MF-20V manufactured by Yuasa Membrane System, nominal pore size 0.2 μm) using a polyester non-woven fabric as a base material was used instead of the PVDF MF membrane as the porous membrane. The functional polymer B was immobilized on the surface of the chlorinated PVC MF membrane by the same operation as in the above. The carbonyl relative strength was defined as the relative strength by standardizing the carbonyl absorption strength derived from the coat layer ( ^{around 1730 cm -1} ) with the absorption strength derived from chlorinated PVC ^{around 1250 cm -1.} The obtained relative strength was 0.110, and the film thickness of the coating layer was 22 nm.

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

(Quantification of protein adsorption amount)
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 the 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 an 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 surface of porous membrane)
As the porous membrane, a hollow filamentous 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, and a 2% methanol solution of the functional polymer B was added at 10 ml / min. Was circulated for 5 minutes. Then, the mixture was switched to methanol and passed through the solution for 3 minutes, and nitrogen was blown into the solution to dry it. Next, UV irradiation was performed for 10 minutes at an irradiation intensity of 100 mW / cm ^{2 using a high-pressure mercury lamp.}

Then, it was washed by passing it through methanol and ultrapure water for 3 minutes each to obtain a PVDF MF membrane on which the PEGMA copolymer was immobilized. To calculate the thickness of PEGMA copolymer layer of the film surface, the relative normalized PEGMA copolymer derived from carbonyl absorption intensity (1730 cm ^-1 before and after) in the absorption intensity of 870 cm ^-1 before and after from PVDF using ATR / FT-IR When the strength was determined, the relative strength was 0.043. In addition, a 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 relative carbonyl strength. When the coating film thickness was estimated from the carbonyl relative strength using this calibration curve, 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 applied to the above PEGMA copolymer-immobilized MF membrane module at 100 ln / min. The liquid was passed for 5 minutes and the increase in the membrane inlet pressure from the start of the liquid passage was measured. The pressure increase was as small as 22 kPa, and it is considered that the pressure increase was also suppressed because the adsorption of the protein on the membrane was suppressed.

Example 13
(Production of Functional Polymer A with Azide Group Content of 9 Mol%)
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 surface of porous membrane)
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 strength of the carbonyl was 0.073, and the film thickness of the coating layer was 12 nm.

(Immersion test in activated sludge tank)
The fouling behavior of the membrane was evaluated using actual activated sludge. A small MBR testing machine (manufactured by Yuasa Membrane) was used as the evaluation device, and activated sludge was sampled from the Kasumi Complex wastewater treatment facility, adjusted to an MLSS concentration of 8000 mg / L, and introduced into the testing machine. For the film element, the surface-modified MF film was attached to both sides of the mold by ultrasonic welding and set in a testing machine. The filtration flux was sucked by 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 performed for one week, and when the increase in the intermembrane differential pressure was measured, the increase in the intermembrane differential pressure was very small at 3 kPa, and fouling could be suppressed.

Comparative Example 1
As the PVDF MF membrane, the same MF membrane having a nominal pore size of 0.2 μm (MV020 manufactured by Microdyne Nadia) used in Example 1 was used to quantify the amount of protein adsorbed.

(Quantification of protein adsorption amount)
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 larger than that in Example 1.

Comparative Example 2
As the PVDF UF membrane, a UF membrane having a molecular weight cut-off of 200,000 (UV200 manufactured by Microdyne Nadia) was used to quantify the amount of protein adsorbed.
(Quantification of protein adsorption amount)
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 larger than that in Example 1.

Comparative Example 3
As an MF membrane made of chlorinated PVC, an MF membrane having a nominal pore size of 0.4 μm (MF-40B made by Yuasamembrane) was used to quantify the amount of protein adsorbed.
(Quantification of protein adsorption amount)
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 larger than that in Example 1.

Comparative Example 4
(Manufacture of Functional Polymer J with Azide Group Content of 48 Mol%)
Functional Polymer I was prepared in the same manner as in Example 1, except that 10 mmol each of PEGMA and methacryloyloxypropyloxy4-phenyl azide was 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 surface of porous membrane)
The functional polymer J was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1 except that the immersion solvent of the separated porous membrane was changed from methanol to chloroform. The relative strength of the carbonyl was 0.20, and the film thickness of the coating layer was 35 nm.

(Quantification of protein adsorption amount)
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 even if the coating layer is sufficiently thick, the amount of insulin adsorbed increases when the amount of the cross-linking component is out of the range of the present invention. The results are summarized in Table 1.

Comparative Example 5
(Production of functional polymer B having an 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 surface of porous membrane)
The functional polymer B was immobilized on the surface of the PVDF MF membrane by the same operation as in Example 1 except that the concentration of the functional polymer B in the methanol solution was 0.5% and the immersion time was changed to 10 seconds. The relative carbonyl strength was 0.011 and the film thickness of the coating layer was 2 nm.

(Quantification of protein adsorption amount)
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 thickness of the coating layer is thin, the amount of insulin adsorbed increases. The results are summarized in Table 1.

Comparative Example 6
(Pressure change when passing protein solution)
An aqueous solution of bovine serum albumin 1000 mg / L was added to an unmodified hollow filament PVDF MF membrane module (UMP-053 manufactured by Asahi Kasei Chemicals Co., Ltd., nominal pore size 0.2 μm) at 100 ln / min. The liquid was passed for 5 minutes, and the increase in the membrane inlet pressure from the start of the liquid passage was measured. The pressure increase was 60 kPa, which was a large value as compared with Example 12. It is considered that the pressure rise 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 size of 0.2 μm (MV020 manufactured by Microdyne Nadia Co., Ltd.) used in Example 1 was used to perform an immersion test in an activated sludge tank.
(Immersion test in activated sludge tank)
When the increase in the intermembrane differential pressure was measured by the same method as in Example 13, the increase in the intermembrane differential pressure reached 45 kPa, and the progress of fouling could be confirmed.

Claims (4)

It is composed 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 functional component containing a hydrophilic group and a reaction between the porous membrane and nitrene. a surface-modified porous membrane comprising a crosslinked component, component introduced into the functional polymer layer, polymer der having the structure represented by the general formula (1) is, the functional polymer layer 5 A surface-modified porous membrane containing up to 30 mol% of a crosslinked component and having a thickness of the functional polymer layer of 5 to 100 nm.
(In the formula, m and n represent integers of 1 or more independently of each other, 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. , alkoxyalkyl group, alkoxy polyoxyethylene group, a hydrophilic group selected from hydroxy polyoxyethylene group, Z is -O- or -N (R 3) _- represents a group represented by, a is -O Representing a group represented by − or −CH _{2− , R 1} , R ₂ and R ₃ independently represent a hydrogen atom or a hydrocarbon group of _{C 1 to} C _{6 , and R 4} represents a group of C _{3 to} C ₆ . It represents a divalent hydrocarbon group, R ₅ represents a fluorine atom, and p represents an integer of 0-4.)

The surface-modified porous membrane according to claim 1, which is used in a membrane separation activated sludge method. A water treatment separation membrane comprising the surface-modified porous membrane according to claim 1 or 2. A functional polymer composed of a functional component and a component having a 5 to 30 mol% nitrene precursor functional group 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 producing a surface-modified porous film according to claim 1 or 2, wherein the surface-modified porous film is formed.