JPH0253089B2 - - Google Patents

Description

[Detailed description of the invention]

Technical Field The present invention relates to a composite semipermeable membrane, and more particularly to a composite semipermeable membrane having excellent semipermeable membrane performance and excellent oxidation resistance. BACKGROUND ART Cellulose acetate-based reverse osmosis membranes, originally developed by Loeb and Sourirajan, have been widely used due to their excellent basic performance and ease of manufacture. Problems such as hydrolyzability due to microorganisms, deterioration due to microorganisms, compactability, and inability to be stored dry have become problems, and various new reverse osmosis membranes using synthetic polymers have been proposed to compensate for these drawbacks. DuPont proposed a reverse osmosis membrane made of fully aromatic polyamide, and although this achieved significant improvements in terms of hydrolyzability and microbial deterioration resistance, it did not surpass cellulose acetate in terms of basic performance. However, the disadvantages of compactability and inability to store under dry conditions still remained. All of these membranes are called heterogeneous membranes that are prepared using a method called phase separation, and the homogeneous layer involved in separation and the porous layer that maintains the strength of the membrane are made of the same material. Ta. However, a method has been proposed in which a porous layer is prepared in advance using a different material, and then a hydrophilic reactive polymer is reacted with a crosslinking agent to form a crosslinked thin film-like separation layer on top of the porous layer. In addition to improved performance, it was suggested that significant improvements could be made in hydrolyzability, microbial degradability, compactability, dry storage stability, etc. North Star Laboratories has demonstrated that the above improvements are possible by using polyethyleneimine as the hydrophilic, reactive polymer and polyacid chlorides or polyisocyanates such as isophthalic acid chloride and toluylene diisocyanate as the crosslinking agent. However, because the amine content of the raw material polyethyleneimine in the membrane thus obtained was too high, the crosslinked layer formed was very weak.
It has been found that there are major problems in creating a spiral module configuration. On the other hand, Universal Oil Products Co., Ltd. succeeded in improving the above drawbacks by using amine-modified polyepichlorohydrin as a hydrophilic reactive polymer.
It has recently become clear that it is difficult to produce a membrane with a large amount of water permeation due to the difficulty in producing the raw material epiamine, and that there are problems with long-term durability. Recently, Film Tech Co., Ltd. (inventor: John E. Kadotsute) has developed a method for applying low-molecular weight aromatic amines such as metaphenylene diamine and paraphenylene diamine to aromatic polymers such as trimesic acid chloride on a microporous membrane. A composite membrane crosslinked with an acid halide was proposed (see Japanese Patent Application Laid-open No. 147106/1983), and was disclosed to have extremely good desalination performance and oxidation resistance. However, as a result of the study by the present inventor, the oxidation resistance of this membrane is only short-term, and as shown in the comparative example of the present invention, in continuous reverse osmosis tests in the coexistence of 4 to 5 ppm active chlorine. It became clear that after only 150 hours, typical membrane deterioration phenomena such as a decrease in salt removal rate and an increase in water permeation rate began to occur. Furthermore, a composite membrane with excellent oxidation resistance obtained by crosslinking a polyamine having only secondary amino groups with an aromatic polyacid halide has been proposed (see Japanese Patent Application Laid-Open No. 139802/1983). Membranes generally have a difficult rate of salt removal, and even when separating large solutes such as magnesium chloride, the salt rejection rate is at most 90~90%.
Only about 95% of sucrose could be obtained, and even in the separation of sucrose, the removal rate was difficult to exceed 95%. DISCLOSURE OF THE INVENTION In view of the drawbacks of these films that have been proposed in the past, the inventors of the present invention have made extensive studies to solve these problems, and have surprisingly found that aliphatic primary amides, which have been conventionally considered to have poor oxidation resistance, have been developed. By appropriately selecting the acid component from the polyamide having bonds, it is possible to obtain a membrane with far superior oxidation resistance and high desalting performance compared to conventionally known semipermeable membranes, especially the membrane invented by Kadotsute et al. The present invention was completed based on the discovery that a high-performance semipermeable membrane having the following characteristics could be obtained. That is, the present invention provides a microporous membrane and a structural unit provided thereon represented by the following formula (). [However, in the formula, R ₁ represents an alkyl group having 1 to 3 carbon atoms which may contain a hydroxyl group or a hydrogen atom, and R ₂ represents an alkyl group having 2 to 15 carbon atoms which may contain an oxygen atom. represents an aliphatic hydrocarbon residue, Ar represents a fused or non-fused aromatic hydrocarbon residue, and X represents a carbonyl bond (

[Formula]) or a sulfonyl bond (-SO ₂ -), at least a part of which represents a direct bond, and Y represents a direct bond in other structural units.

This is the crosslinking point that bonds with [Formula], and the others are −OM or

Represents [formula]. However, M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an ammonium group, and the definition of R ₃ is the same as R ₁ , but at least one R ₃ is a hydrogen atom. ] A composite semipermeable membrane comprising a crosslinked polymer thin film containing at least 50 mol% of The composite semipermeable membrane of the present invention has a crosslinked polymer thin film having a structural unit represented by the formula () above on a microporous membrane described below.
R ₁ is an alkyl group having 1 to 3 carbon atoms which may contain a hydroxyl group or a hydrogen atom. Therefore, R ₁ is a hydrogen atom, -CH ₃ , -
C ₂ H ₅ , −C ₃ H ₇ , −C ₂ H ₄ OH, −CH ₂・CH(OH)・
_CH3 , preferably a hydrogen atom, _-CH3 , -
_{C2H5 , -C3H7} , particularly preferably _a hydrogen atom. Further, R ₂ is an aliphatic hydrocarbon residue having 2 to 15 carbon atoms, preferably 2 to 14 carbon atoms, which may have an oxygen atom, but aliphatic here refers to a straight-chain or branched aliphatic residue. It may also be cycloaliphatic. Therefore, as R ₂ , −CH ₂ CH ₂ −, −CH ₂・
CH ₂・CH ₂ −, −(CH ₂ −) _o (n=4 to 11),

【formula】

【formula】

【formula】

[Formula] is mentioned, preferably -CH ₂ ·CH ₂ -, -CH ₂ ·CH ₂ ·CH ₂ -,

【formula】

[Formula] CH ₂ −,

[Formula]. Ar is a fused or non-fused aromatic hydrocarbon residue, preferably having 6 to 13 carbon atoms. However, as Ar,

【formula】

【formula】

【formula】

[Formula] (L=-O-, -CH ₂ -,

【formula】) etc., especially

[Formula] is preferred. X is a carbonyl bond or a sulfonyl bond, preferably a carbonyl bond. At least a portion of Y must be a direct bond and serve as a crosslinking point, and other components include -OM or

[Formula] can be represented. Here, M is a hydrogen atom, an alkali metal,
alkaline earth metal or ammonium group,
Among these, hydrogen atoms or alkali metals are preferred. Also, R ₃ can be the same as R ₁ , but at least one of R ₃ is a hydrogen atom. Y is preferably 30 to 90%, particularly preferably
It is preferable that 50 to 70% of the bond is a direct bond and is involved in crosslinking, and preferably all of the bond is involved in crosslinking. The crosslinked polymer thin film contains at least 50 structural units represented by the formula () having the above structure.
Although it is necessary to contain it in mol%, it is more preferable to contain it in an amount of 60 mol% or more. Constituent units other than those represented by formula () are not particularly limited as long as they do not impair the effects of the present invention, but if a small amount of a constituent unit derived from an aliphatic diamine containing only a secondary amine is contained. In addition, water permeability can be improved without impairing the effects of the present invention, which are oxidation resistance and high salt exclusion properties. The structural unit is the following formula () [However, in the formula, R ₄ and R ₅ each independently have 1 to 1 carbon atoms that may contain a hydroxyl group.
3 alkyl groups, or R ₄ and R ₅ are bonded to each other or each to R ₆ and are substituted with a methyl group or/and an ethyl group together with the two nitrogen atoms to which they are bonded and R ₆ R ₆ represents an aliphatic hydrocarbon residue having 2 to 15 carbon atoms which may have an oxygen atom. Ar,
X and Y are as defined above. ] The structural unit represented by these can be mentioned. In the formula, R ₄ and R ₅ may be an alkyl group having 1 to 3 carbon atoms which may have a hydroxyl group,
Specifically, those mentioned above for R ₁ are exemplified, and preferably -CH ₃ , -C ₂ H ₅ , -C ₂ H ₄ OH, -
_{C3H7 and} especially _{-C2H5 .} Also, R ₄ and R ₅ are bonded to each other or each
Together with R ₆ and the two nitrogen atoms to which they are bonded, they can form a piperazyl group or dipiperidylalkylene group which may be substituted _with a methyl group, preferably an unsubstituted piperazyl group. It is something that forms. Further, Ar, X and Y are as described above. The structural unit represented by the above formula () is 40 mol%
In a preferred embodiment, the content may be 5 mol% to 30 mol%. Further, the crosslinked polymer thin film of the present invention has a structural unit derived from an aromatic diamine, that is, the following formula () [However, in the formula, R ₇ and R ₈ are the same or different hydrogen atoms or methyl groups, Q has 6 to 15 carbon atoms, which may be substituted with -COOM and/or -SO ₃ M, and is an ether It is a non-fused aromatic hydrocarbon residue which may have a bond, and Ar, X, Y and M are as defined above. ] It is also possible to contain the structural unit represented by 30 mol % or less. As for Q,

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] is mentioned, especially

【formula】

[Formula] is preferred. Further, the crosslinked polymer thin film of the present invention contains 40 mol% or less, preferably 30 mol% or less of the following formula () [However, in the formula, R ₉ and R ₁₀ are the same or different,
represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms which may contain a hydroxyl group,
Or R ₉ and R ₁₀ are combined with each other or each R ₁₁
to form a piperazyl group or dipiperidyl alkylene group which may be substituted with a methyl group or ethyl group together with the two nitrogen atoms to which they are bonded, R ₁₁ , and R ₁₁ has an oxygen atom. an aliphatic hydrocarbon residue having 2 to 15 carbon atoms, which may be substituted with -COOM and/or -SO ₃ M, and which may contain an ether bond; represents a non-fused aromatic hydrocarbon residue, where M represents a hydrogen atom, an alkali metal, an alkaline earth metal or an ammonium group,
Ar' represents a non-fused or fused aromatic hydrocarbon residue having 6 to 15 carbon atoms and which may contain an ether bond or a sulfonyl bond. ] It may contain the structural unit represented by these. The crosslinked polymer thin film of the present invention can be further covered with a protective film, and the protective film may be a film of a water-soluble polymer such as polyvinylpyrrolidone or polyvinyl methyl ether, a water-insoluble polyvinyl alcohol film, or a porous aliphatic polyamide film. can be mentioned. Among these, water-insoluble polyvinyl alcohol membranes or porous aliphatic polyamide membranes are preferred, and the water-insoluble polyvinyl alcohol membranes include polyvinyl alcohol that has been thermally gelled or cross-linked with glutaraldehyde, formalin, glyoxal, or sulfite adducts thereof. Examples of porous aliphatic polyamide membranes include porous membranes of aliphatic polyamides such as poly-ε-caproamide and polyhexamethyladipoamide. Examples of the microporous membrane used as a support in the present invention include porous glass materials, sintered metals, ceramics, and organic polymers such as cellulose ester, polystyrene, vinyl butyral, polysulfone, and vinyl chloride. Polysulfone membranes have particularly excellent performance as microporous membranes of the present invention, and polyvinyl chloride is also effective. The manufacturing method for polysulfone microporous membranes is described in the U.S. Office of Salt Water Report (OSW).
It is also stated in Report) No. 359. Such membranes generally have surface pore sizes of about 100 to
The surface pore size is preferably between 1000 angstroms, but is not limited to this, depending on the application of the final composite membrane.
It can vary between 5000 Å. These microporous membranes can be used with either a symmetrical or asymmetrical structure, but preferably an asymmetrical structure. However, these microporous membranes have a membrane constant of 10 ^-4 g/cm ²・sec・
If it is below atm, the water permeability will be too low and 1
If it is more than g/cm ² ·sec·atm, the desalination rate tends to be extremely low, which is not preferable. Therefore, the preferred film constant is in the range of 1 to 10 ^-4 g/cm ² ·sec·atm, particularly preferably in the range of 10 ^-1 to ^{10 -3} g/cm ² ·sec·atm, giving the most favorable results. The membrane constant here is a value representing the amount of pure water permeated under a pressure of 2Kg/ ^cm2 , and the unit is g/ ^cm2・sec・atm.
It is. It is preferable to use such a microporous membrane with the back side reinforced with a woven or nonwoven fabric. Suitable examples of such woven or nonwoven fabrics include those made of polyethylene terephthalate, polystyrene, polypropylene, nylon, or vinyl chloride. Thus, the composite semipermeable membrane of the present invention has a thickness of 40 μm to 5 μm.
In the case of a microporous membrane of about mm in thickness, especially in the case of an organic polymer microporous membrane, a microporous membrane with a thickness of 40 μm to 70 μm is
The above-mentioned crosslinked polymer thin film with a thickness of 200 Å to 1500 Å is provided, and if necessary, a protective film with a thickness of 0.1 μm to 1 μm is further provided thereon. The composite membrane of the present invention has the following formula () R ₁ NH-R ₂ -NH ₂ ... () [However, in the formula, R ₁ and R ₂ are as defined above. ]
A diamine compound containing at least 50 mol%, preferably 60% or more of an aliphatic diamine represented by the following formula () is applied on a microporous membrane. [However, in the formula, Ar is as defined above, Z represents the same or different halogen atom, and X represents a sulfonyl bond or a carbonyl bond. ] It is obtained by a crosslinking reaction with a crosslinking agent mainly consisting of an aromatic polyacid halide represented by the following. The aliphatic diamine represented by the above formula () used in the present invention is one that is soluble in a solvent, preferably water or a lower alcohol. Examples of such diamines are as follows. H ₂ NCH ₂ CH ₂ NH ₂ , H ₂ NCH ₂ CH ₂ CH ₂ NH ₂ H ₂ N− (CH ₂ −) ₄ NH ₂ , H ₂ N− (CH ₂ −) ₅ NH ₂ H ₂ N− (CH ₂ −) ₆ NH ₂ , H ₂ N− (CH ₂ −) ₇ NH ₂ H ₂ N− (CH ₂ −) ₈ NH ₂ , H ₂ N− (CH ₂ −) ₉ NH ₂ H ₂ N− (CH ₂ −) ₁₀ NH ₂ , H ₂ N − (CH ₂ −) ₁₁ NH ₂ (CH ₃ −) NHCH ₂ CH ₂ NH ₂ , (C ₂ H ₅ −)
NHCH ₂ CH ₂ NH ₂ HOCH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ ,

[Formula] H ₂ NCH ₂ CH ₂ OCH ₂ CH ₂ NH ₂ ,
H ₂ NCH ₂ CH ₂ CH ₂ OCH ₂ CH ₂ CH ₂ NH ₂

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

Particularly preferred among these aliphatic diamines are ethylenediamine and cyclohexanediamine. The above aliphatic diamines may be used alone or in combination of two or more. It is also within the scope of the present invention to use these diamines in combination with other polyamine compounds.
As such polyamines, the following can be suitably used. (1) Linear aliphatic secondary diamine CH ₆ NHCH ₂ CH ₂ NHCH ₃ C ₂ H ₆ NHCH ₂ CH ₂ NHC ₂ H ₅ HOCH ₂ CH 2 NHCH ₂ CH ₂ NHCH _{2 CH 2 OH} (2) Cycloaliphatic Secondary diamine piperazine

[Formula] 2-methyl piperazine

[Formula]-ethylpiperazine

[Formula] 2,5-dimethylpiperazine

[Formula] Dipiperidylpropane

[Formula] By using these polyamines in combination, the water permeability and/or salt removal rate of the composite membrane of the present invention can be appropriately adjusted and improved. Although not particularly preferred, the following aromatic diamines may also be mixed and used within a range that does not impair the effects of the present invention, for example, within a range of 30 mol % or less. (3) Aromatic diamine metaphenylene diamine (

【formula】), Paraphenylenediamine (

[Formula]), 4,4-diaminodiphenylamine (

[Formula]), 4,4'-diaminodiphenyl ether (

[Formula]), 3,4'-diaminodiphenyl ether (

[Formula]), 3,3'-diaminodiphenylamine (

[Formula]), 3,5-diaminobenzoate (

[Formula] represents a carboxylic acid salt. When these diamines are used, the aliphatic secondary diamine is 50 mol% or less, preferably 40 mol% or less, particularly 30 mol% or less, and the aromatic diamine is 30 mol% or less based on the entire diamine component. . In order to obtain the composite membrane of the present invention using the diamine compounds described above, a solution of these amine compounds must be applied onto the microporous membrane described below. The coating method may be any method such as dipping, roll coating, or wick coating, but the thickness of the applied amine compound layer is 0.01 to 2μ, preferably 0.02 to 1μ, more preferably 0.05 to 0.7μ. Coating conditions should be controlled so that If the coating layer of the amine compound layer is smaller than the above lower limit (ie, 0.01μ), the active layer of the finally obtained composite membrane will be too thin and the mechanical strength will decrease. Also, the coating layer is 2μ
If the active layer is thicker than , the active layer becomes too thick, and there is a strong tendency to impair the water permeability of the composite membrane. Such diamines must be soluble, especially in water,
0.1 g/methanol, ethanol, isopropanol, methyl cellosolve, dioxane, tetrahydrofuran, or a mixed solvent of two or more of these.
It is preferable that it is soluble in 100 ml or more, preferably 0.5 g/100 ml or more. Especially for water 0.1g/100
It is preferable to have a solubility of at least 0.5 g/100 ml, more preferably at least 0.5 g/100 ml. A solution of the diamine compound of the present invention dissolved at least 0.1% in at least one solvent selected from these solvent groups (particularly preferably water) is applied or impregnated onto the microporous membrane. The microporous membrane coated with the aforementioned diamine is an aromatic acid halide represented by the aforementioned formula () containing a functional group that can react with the amino group to form either a carbonamide bond or a sulfonamide bond. The diamine is crosslinked into a thin film on the microporous membrane. The functional group contained in the polyfunctional compound as a crosslinking agent that can be used in the present invention is either a carbonyl halide group (COZ) or a sulfonyl halide group (-SO ₂ Z), and three of these functional groups are contained in one molecule. This includes: Particularly preferred functional groups are acid chloride groups and sulfonyl chloride groups. These 1
The plurality of functional groups present in the molecule may be of the same type or may be different from each other. Further, as the polyfunctional compound, aromatic polyfunctional compounds are effective. Specific examples of these crosslinking agents include the following.

【formula】

【formula】

【formula】

【formula】

[Formula] (However, L=-O-, -CH ₂ -,

[However, Z has the same meaning as the definition in the above formula (). ]

Examples of such bifunctional compounds include the following.

【formula】

【formula】

【formula】

【formula】

[Formula] When these bifunctional compounds are used, their usage ratio is 1 to 50 mol%, preferably 5 to 30 mol%, based on the trifunctional compound. The composite membrane of the present invention can be obtained by bringing the diamine described above into contact with a solution of the polyfunctional compound described above on the microporous membrane. The solvent used to dissolve the polyfunctional compound is one that does not substantially dissolve the polyamine compound and the base material, such as n-hexane, n-heptane,
n-octane, cyclohexane, n-nonane, n
Examples include hydrocarbon solvents such as -decane and halogen hydrocarbons such as carbon tetrachloride, difluorotetrachloroethane, trifluorotrichloroethane, and hexachloroethane. The suitable concentration of the polyfunctional compound in the solvent depends on the type of the compound, the solvent, the base material,
Although it may vary depending on other conditions, the optimum value can be determined through experimentation. But generally about 0.1~5.0, preferably 0.5~
A sufficient effect can be exhibited at 3.0% by weight. Crosslinking of the polyamine compound with a polyfunctional compound is preferably achieved by immersing a membrane coated with the polyamine compound in a solution of the polyfunctional compound, thereby causing a reaction at the interface between the membrane and the solution. At this time, in order to promote this interfacial crosslinking reaction, it is also possible to previously include an interfacial reaction accelerator in the diamine compound described above or in the solution of the polyfunctional compound. As such a promoter, caustic alkali, sodium phosphate, pyridine, tertiary amine, surfactant, sodium acetate, etc. are suitably used. Such interfacial crosslinking reaction between the diamine compound and the polyfunctional compound is carried out at room temperature to about 100°C, preferably at 20°C to about 100°C.
It can be carried out at a temperature of 50°C for 2 seconds to 10 minutes, preferably 10 seconds to 5 minutes. This interfacial crosslinking reaction can be carried out so that it is mainly concentrated on the surface of the membrane. Next, the membrane supported on the substrate is dried at room temperature or at 40 to 130°C as necessary, after draining excess polyfunctional compound solution for 10 seconds to 2 minutes.
The heat treatment is preferably carried out at a temperature of 50 to 80°C for about 1 to 30 minutes, preferably about 5 to 20 minutes.
Thereby, the interfacial crosslinking reaction can be completed and the diamino compound can be rendered water-insoluble. In this way, a composite membrane having a thin membrane of a crosslinked polycondensate having permselectivity on the microporous membrane surface is obtained. Although the above example has been described in which the diamino compound is first applied onto the microporous membrane, it is also possible to apply the crosslinking agent onto the microporous membrane first and then react with the diamine compound. Examples of crosslinked polyamides that can be used to form the composite membrane active layer of the present invention are shown below. The composite membrane of the present invention thus obtained has excellent basic reverse osmosis performance, compaction resistance, heat resistance, and
In addition to its PH properties, it has extremely amazing oxidation resistance, and can be said to have advantages and characteristics that are completely different from conventionally known membranes. In the present invention, a water-soluble or water-insoluble protective film can be further provided on the crosslinked polymer thin film of the composite semipermeable membrane obtained as described above. Such protective films include polyvinylpyrrolidone,
Membranes of compounds such as polyvinyl methyl ether can be mentioned as water-soluble protective membranes, and water-insoluble protective membranes can include water-insolubilized polyvinyl alcohol membranes and porous aliphatic polyamide membranes. A protective film of polyvinyl pyrrolidone or polyvinyl methyl ether can be obtained by dissolving the above polymer in a solvent such as water, lower alcohol, or a mixed solvent thereof, applying the solution on a crosslinked polymer thin film, and drying. A water-insolubilized polyvinyl alcohol film is produced by dissolving polyvinyl alcohol in water together with one or more compounds selected from formalin, glyoxal, glutaraldehyde, and their sulfites, or together with ammonium persulfate and/or potassium persulfate to form a crosslinked polymer thin film. After being coated on top, heat treatment is performed at 50 to 120°C, preferably 70 to 100°C, for 5 to 30 minutes to effect acetal crosslinking or self-gelation. A porous aliphatic polyamide membrane is prepared by dissolving aliphatic polyamide in a methanol solution containing a pore opening agent such as calcium chloride, applying the solution onto a crosslinked polymer thin membrane and drying it to form a polyamide membrane. , can be obtained by extracting the pore-opening agent with water to make it porous. The composite semipermeable membrane thus obtained can be applied to various membrane separation operations. In normal membrane separation operations, the membrane is cleaned with a disinfectant after treatment for a certain period of time, and chlorine-based disinfectants are often used at this time. Conventional membranes deteriorate when treated with high-concentration chlorine-based disinfectants, but the composite membrane of the present invention has high oxidation resistance and can be used satisfactorily. Furthermore, in the present invention, it is also effective to treat the membrane with a reducing agent solution after treatment with a chlorine-based disinfectant to remove chlorine adsorbed to the membrane and further restore the performance of the membrane. Such sterilization methods include disinfectants such as sodium hypochlorite, hypochlorous acid, hypobromic acid, hydrogen peroxide, sodium perborate, iodophor, and sodium dichloroisocyanurate at 0.5 ppm.
An example is a method of contacting the membrane with an aqueous solution of PH4 to PH7 containing ~5000 ppm at 10°C to 50°C for 10 to 100 minutes. Among the above disinfectants, the reducing agent treatment method that can be applied after using a chlorine-based disinfectant includes 10 ppm to 5000 ppm of reducing agents such as sodium thiosulfate, sodium hydrosulfite, sodium sulfite, and sodium bisulfite. Using an aqueous solution of
Examples include a method of contacting with a membrane at 10°C to 50°C for 10 minutes to 100 minutes. The membrane regeneration method described above is particularly effective in the field of membrane separation of solutions in which microorganisms easily propagate, such as aqueous solutions containing sugars, amino acids, alcohols, or organic carboxylic acids. Hereinafter, the present invention will be explained in more detail with reference to Examples. Reverse osmosis test method: Using a regular continuous pump type reverse osmosis device, at 25°C.
An aqueous solution of pH 6.0 to 6.5 containing 5000 ppm of NaCl and 4 to 5 ppm of hypochlorous acid at all times was used as the stock solution, and the operating pressure was 42.5 Kg/cm ² G. Accelerated chlorine resistance evaluation method In addition to the above reverse osmosis test method, hypochlorous acid concentration
An accelerated test of chlorine resistance was carried out by increasing the concentration to 1000 ppm. Note that the membrane performance in this case shows data after further treatment with a reducing agent. Salt rejection rate The salt rejection rate in the examples is a value determined by the following formula. Salt rejection rate (%) = (1 - NaCl concentration in permeated water / NaCl concentration in stock solution) ×
100 Reference Example 1 Manufacture of Polysulfone Porous Support Membrane A densely woven Dacron nonwoven fabric (fabric weight 180 g/m ² ) was fixed on a glass plate. Next, a solution containing 12.5 wt% polysulfone, 12.5 wt% methyl cellosolve, and the balance dimethylformamide is cast on the nonwoven fabric in a layer having a thickness of about 0.2 mm, and the polysulfone layer is immediately gelled in a water bath at room temperature. As a result, a highly porous nonwoven polysulfone membrane was obtained. Electron micrographs show that the porous polysulfone layer obtained in this way has a thickness of about 40 to 70μ, has an asymmetric structure, and has many micropores of about 200 to 700Å on the surface. observed. In addition, these porous substrates have a pure water permeation rate (membrane constant) of approximately 3.0 to 7.0×10 ^-2 g/cm ² at 2 Kg/cm ³ G.
It was sec/atm. Example 1 The polysulfone microporous membrane obtained in Reference Example 1 was immersed for 5 minutes in an aqueous solution of 1 g of ethylenediamine (immediately distilled) dissolved in 100 ml of distilled water, and then the membrane was pulled out of the aqueous solution and held vertically at room temperature. Drained for 7 minutes. The membrane thus drained was then immersed in 0.5 wt % trimesic acid chloride in n-hexane for 20 seconds, and then air-dried at room temperature for 30 minutes. The thus obtained composite membrane was subjected to a reverse osmosis test under the conditions of Reference Example 1, with a salt removal rate of 98.9% and a water permeability of 41.3.
It showed an initial performance of /m ³ hr. Continue to use this under the same conditions (PH6.0~6.5 hypochlorous acid 4~
When the reverse osmosis test was continued (while constantly controlling the stock solution at 5ppm), at the 200th hour, 99.1%,
37.5/m ²・hr, 99.3% at 500th hour, 31.4/
^m2・hr, and further 99.3% at 1000th hour, 28.6/
Although the water permeability decreased slightly to m ² hr, the desalination rate showed extremely stable performance. The composite membrane of Example 1 produced under the above conditions was immersed in a 0.1% NaOH aqueous solution for one day and night, and then washed repeatedly with distilled water and the membrane was vacuum-dried. Thereafter, the crosslinked active layer polymer, which can be isolated by immersing this membrane in chloroform and eluting the polysulfone microporous membrane, is thoroughly washed with chloroform, followed by washing with alcohol and water, purification, and drying. Na atomic absorption analysis of the polymer powder revealed sodium carboxylate groups (-
0.53 meq/g of Na was detected in terms of COONa). The composition of the polymer estimated using this value is as follows. Comparative Example 1 Example 1 except that an aqueous solution of 2 g of metaphenylenediamine immediately after distillation was dissolved in 100 ml of distilled water was used.
A composite membrane was obtained in exactly the same manner. When this product was subjected to a chlorine resistance reverse osmosis test under the same conditions as in Example 1, the initial performance was 26.5/m ² ·hr,
It showed a value of 98.5%. Furthermore, when the reverse osmosis test was continued under the same conditions, the desalination rate improved to 27.3/m ² hr and 99.7% at the 100th hour, but it decreased to 41.9/m ² hr and 99.7% at the 200th hour. 99.3%, 500
The performance changed to 56.4/m ² ·hr, 98.2% at the 1000th hour, and further to 67.3/m ² ·hr, 93.2% at the 1000th hour, exhibiting a membrane deterioration phenomenon. Examples 2 to 6 Composite membranes were obtained in exactly the same manner as in Example 1, except that amines shown in Table 1 below were used instead of ethylenediamine. These membranes were subjected to an oxidation resistance reverse osmosis test under the same conditions as in Example 1. The results are shown in Table 1. In addition, Na analysis value and C,
Table 2 shows the composite membrane active layer polymer composition determined from H and N elemental analysis values.

【table】

【table】

【table】

[Table] Example 7 A composite membrane was obtained in exactly the same manner as in Example 1 except that 5-chlorosulfonylisophthalic acid chloride was used instead of trimesic acid chloride as a crosslinking agent. This product is similar to Example 1.
As a result of Na analysis, it was found to be a composite membrane consisting of a crosslinked polymer layer having the following polymer composition. When this membrane was subjected to an oxidation resistance RO test under the same conditions as in the example, it showed initial values of water permeability of 56.3/m ² ·hr and salt removal rate of 89.2%. Furthermore, when the test was continued under the same conditions, at the 200th hour it was 43.6
/m ²・hr, 93.3%, 41.0/m at 500th hour
^m2・hr, 95.1%, further 37.4/ at 1000th hour
The performance was 97.7% m ² hr. Example 8 In Example 1, instead of using only trimesic acid chloride as a crosslinking agent, a 3:1 (molar ratio) mixture of trimesic acid chloride and isophthalic acid chloride was used,
A composite membrane was obtained in the same manner as above. As a result of conducting Na analysis and elemental analysis (C, H, N) on this composite membrane active layer polymer in the same manner as in Example 1, it was found that this polymer was a crosslinked polymer having the polymer composition of the following formula. Ivy. [Na analysis value: 5.74%, C: 54.96%, H: 3.84%, N: 11.95%] When this composite membrane was subjected to an RO test under the same conditions as in Example 1, the initial performance was 54.1/m ² ·hr,
91.7%, 48.2/ ^m2・hr after 200 hours continuous test,
93.0%, 45.5/ ^m2・hr at 500th hour, 95.4%,
Furthermore, at the 1000th hour, the performance was 39.4/m ² ·hr, 96.3%. Examples 9 to 12 Composite membranes were obtained in exactly the same manner as in Example 1, except that instead of using only ethylenediamine, a mixture of diamine and ethylenediamine (1:2 molar ratio) listed in Table 2 below was used. . When these membranes were subjected to a chlorine resistance RO test under the same conditions as in Example 1, the following results were obtained. Further, Table 4 shows the compositions of these composite membrane active layer polymers.

【table】

【table】

[Table] Example 12-2 to 16 Instead of using the ethylenediamine aqueous solution in Example 1, 1/2 of the aliphatic diamine shown in Table 1 below was used.
A composite membrane was prepared in exactly the same manner except that a 50 molar aqueous solution was used. After evaluating the basic separation performance of this composite membrane, a chlorine test and a reducing agent cleaning test were conducted under the following conditions to examine changes in membrane performance.

[Table] Examples 17-18 Instead of using only trimesic acid chloride as a crosslinking agent in Example 1, an equimolar mixture of trimesic acid chloride and isophthalic acid chloride or 5-sulfoisophthalic acid trichloride (0.2 wt% carbon chloride solution)
A composite membrane was obtained in exactly the same manner except that . The basic separation performance and chlorine resistance of these composite membranes were evaluated under the same conditions as in Examples 12-16. Table 2 shows the results.
Shown below.

【table】

[Table] Examples 19 to 25 Using the membrane of Example 1, the removal performance of various water-soluble organic substances shown in Table 3 below was investigated.

【table】

[Table] Examples 26 to 29 A protective polymer solution having a composition shown in Table 4 below was applied to the surface of a composite membrane obtained in the same manner as in Example 1 to form a protective layer having a thickness of 0.2 to 0.3μ. formed. When these composite membranes were subjected to a chlorine test under the same conditions as in Examples 12-16, it was found that the long-term durability was significantly improved due to the presence of the protective layer.

[Table] Examples 30 to 32 and Comparative Example 2 Composite membranes obtained in the same manner as Example 1 (Examples 30 to 32)
32) and a composite membrane obtained in the same manner as Comparative Example 1 (Comparative Example 2) was mixed with a 2% aqueous solution of various oxidizing agents shown in Table 5 below.
The sample was soaked for 20 hours at room temperature. Table 5 shows the results of confirming changes in membrane performance. Industrial applicability

[Table] In addition to its high permselective performance, the composite semipermeable membrane of the present invention has high oxidation resistance.
It can be widely used for membrane separation for valuable substance concentration, water-soluble organic matter fractionation, etc., and in particular for microorganisms, which were difficult to use because conventional membranes are not resistant to strong sterilizing agents. It can be effectively used in membrane separation in the food field, etc., where bacteria easily proliferate.

Claims (1)

[Claims] 1. A microporous membrane and a structural unit provided thereon represented by the following formula () [However, in the formula, R ₁ represents an alkyl group having 1 to 3 carbon atoms which may contain a hydroxyl group or a hydrogen atom, and R ₂ represents an alkyl group having 2 to 15 carbon atoms which may contain an oxygen atom. represents an aliphatic hydrocarbon residue, Ar represents a fused or non-fused aromatic hydrocarbon residue, and X represents a carbonyl bond (-CO-)
or represents a sulfonyl bond (-SO ₂ --); at least a portion of Y represents a direct bond and serves as a crosslinking point for bonding to [Formula] in another structural unit; the rest represents -OM or [Formula]; However, M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an ammonium group, and R ₃
has the same definition as R ₁ but with at least one R ₃
is a hydrogen atom. A composite semipermeable membrane comprising: 2. The composite semipermeable membrane according to claim 1, wherein _R2 is an aliphatic hydrocarbon residue having 2 to 14 carbon atoms. 3. The composite semipermeable membrane according to claim 1, wherein Ar is a condensed or non-condensed aromatic hydrocarbon residue having 6 to 15 carbon atoms. 4. The composite semipermeable membrane according to claim 1, wherein R ₁ is a hydrogen atom. 5. The composite semipermeable membrane according to claim 1, wherein the proportion of direct bonding of Y is 30 to 90%. 6. The composite semipermeable membrane according to claim 1, wherein the proportion of direct bonding of Y is 50 to 70%. 7 Claim 1 in which X is a carbonyl group
Composite semipermeable membrane as described in section. 8 Constituent units other than those represented by formula () are the following general formula () [However, in the formula, R ₄ and R ₅ each independently have a carbon atom number of 1 which may contain a hydroxyl group.
~3 alkyl groups, or R ₄ and R ₅ are substituted with each other or each of the two nitrogen atoms to _{which they are bonded and R 6 with} a methyl or ethyl group; R ₆ represents an aliphatic hydrocarbon residue having 2 to 15 carbon atoms and optionally having an oxygen atom. Ar,X
and Y are as defined above. ] The composite semipermeable membrane according to claim 1, which is represented by: 9. The composite semipermeable membrane according to claim 8, wherein the content of the structural unit represented by the general formula () is 1 mol% to 40 mol%. 10 In formula () and formula (), R ₁ is a hydrogen atom, R ₂ and R ₆ are both -C ₂ H ₄ -, Ar is [Formula] X is a carbonyl bond and Y is a direct bond, R ₄ , R ₅ are both ethyl groups,
9. The composite semipermeable membrane according to claim 8, wherein the membranes are bonded to each other to form an ethylene group, and the content of the structural unit represented by formula () is 5 mol% to 30 mol%.