KR20190096347A - Composite Semipermeable Membrane and Manufacturing Method Thereof - Google Patents

Abstract

An object of the present invention is to provide a composite semipermeable membrane capable of realizing excellent fouling resistance over a long period of time. The present invention comprises a support membrane (substrate and porous support layer) and a separation functional layer provided on the porous support layer and comprising a crosslinked polyamide and a hydrophilic polymer, and the condition (A) (the hydrophilic polymer has a positive charge) The present invention relates to a composite semipermeable membrane containing a functional group and a functional group having a negative charge, wherein the hydrophilic polymer is negatively charged) and (B) (the hydrophilic polymer is covalently bonded to the crosslinked polyamide).

Description

Composite Semipermeable Membrane and Manufacturing Method Thereof

The present invention relates to a composite semipermeable membrane having a high water permeation rate and a high adhesion inhibiting ability to membrane contaminants. The composite semipermeable membrane obtained by the present invention can be suitably used, for example, for desalination of water and seawater.

The separation membrane is used to exclude substances (eg salts) dissolved in a solvent (eg water). The fouling phenomenon is a subject in the separation technique using a separation membrane. A fouling phenomenon is a phenomenon in which the permeation | transmission of a solution is impaired because the substance etc. which are contained in the to-be-processed water are adsorb | sucked to the surface of a separation membrane, or an internal hole, and the separation performance of a separation membrane deteriorates. The fouling phenomenon is classified according to the type of substance to be attached, and there are chemical fouling by adsorption of organic matter and bio fouling by adsorption of microorganisms.

In chemical fouling, organic matter contained in the water to be treated, such as drainage, is deposited on the surface of the separation membrane or adsorbed to the inside of the separation membrane, causing the membrane to be clogged, and the permeation amount of the treated water decreases, thereby degrading separation performance. It is a phenomenon.

On the other hand, biofouling is a phenomenon in which the membrane is clogged by breeding on the surface or inside of the membrane by using the organic matter adsorbed to the separator by the aforementioned chemical fouling as a nutrient source. Fouling significantly degrades the permeability of the separator. Therefore, it has been studied to modify the separation membrane to impart adsorptive inhibition.

As a method of modifying a separation membrane and providing an adsorption inhibitory ability, the method of giving hydrophilic polymers, such as polyvinyl alcohol, to a membrane surface is known (patent document 1). In recent years, cationic ion fouling inhibitors such as phosphorylcholine have also been developed. In Patent Literature 2, a monomer having a phosphorylcholine-like group and a monomer having an alkyl methacrylate or an organosilicon group are copolymerized to form a crosslinked structure by hydrophobic interaction or silane coupling, thereby separating the membrane. It is disclosed to adsorb a polymer having a phosphorylcholine like group on its surface. In addition, Patent Document 3 discloses adsorbing a polymer having a phosphorylcholine-like group on the surface of the separator by electrostatic interaction by copolymerizing a monomer having a phosphorylcholine-like group with a cationic (meth) acrylamide.

International Publication No. 97/34686 Japanese Patent Laid-Open No. 2006-239636 Japanese Patent Publication No. 2015-150544

However, in the conventional separation membrane, the water permeability decrease may not be sufficiently suppressed. In particular, in the presence of a foulant having a negative charge such as humus, the water permeability may be significantly reduced.

An object of this invention is to provide the composite semipermeable membrane which can implement | achieve excellent fouling resistance over a long term, and its manufacturing method. In particular, a composite semipermeable membrane expressing excellent fouling resistance is also proposed for treated water having a high salt concentration such as seawater, and a method for producing the same.

The present invention for achieving the above object has the following configuration.

<1> A composite semipermeable membrane comprising a support membrane including a substrate and a porous support layer, and a separation functional layer provided on the porous support layer,

The composite semipermeable membrane, wherein the separation functional layer contains a crosslinked polyamide and a hydrophilic polymer, and satisfies the following conditions (A) and (B).

(A) The said hydrophilic polymer contains the functional group which has a positive charge, and the functional group which has a negative charge, and the said hydrophilic polymer is negatively charged.

(B) The said hydrophilic polymer is covalently bonded to the said crosslinked polyamide.

<2> In the hydrophilic polymer, the ratio (N1 / N2) of the number (N1) of the functional group having a positive charge and the number (N2) of the functional group having the negative charge is 15/85 or more and 45/55 or less, The composite semipermeable membrane described in 1>.

The composite semipermeable membrane as described in said <1> or <2> whose weight average molecular weights of a <3> above-mentioned hydrophilic polymer are 2,000 or more and 1,500,000 or less.

<4> The composite semipermeable membrane according to any one of <1> to <3>, wherein a charge density of the hydrophilic polymer is 7.5 mmol / g or more and 10.5 mmol / g or less.

<5> The composite semipermeable membrane according to any one of <1> to <4>, in which the negative charge density of the hydrophilic polymer is 4.5 mmol / g or more and 8.0 mmol / g or less.

<6> In the separating functional layer, when the bubbles contact angle of the air bubble contact angle of the aqueous solution of pH3 during θ _A, an aqueous solution of pH11 θ _{B La, 150 ° <θ A, θ} B <180 ° and ( The composite semipermeable membrane according to any one of the above <1> to <5>, which satisfies θ _B -θ _A )> 5 °.

<7> The <1> to <6, wherein the hydrophilic polymer contains a functional group having a charged, wherein the charged is a copolymer of monomer P having a negative charge, a functional group having a positive charge, and a functional group having a negative charge. The composite semipermeable membrane in any one of>.

<8> The ratio (PN: QN) of the number (PN) of the monomer units derived from the monomer P contained in the copolymer and the number (QN) of the monomer units derived from the monomer Q is 80:20 to 20:80. And the composite semipermeable membrane according to the above <7>.

The composite semipermeable membrane as described in said <7> or <8> whose <9> above-mentioned monomer P is at least 1 sort (s) of compound chosen from the group which consists of acrylic acid, methacrylic acid, and maleic acid.

<10> The composite semipermeable membrane according to any one of <7> to <9>, in which the monomer Q is at least one compound represented by the following Formula (1) or Formula (2).

(In the formulas (1) and (2), R ¹ is H or CH ₃ , and R ² , R ³ , R ^6, and R ⁷ are each independently an alkylene group having 1 to 5 carbon atoms, or 1 carbon atom. Is an oxyalkylene group of 5 to 5, R ⁴ , R ⁵ , R ⁸ , R ⁹ and R ¹⁰ are each independently an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, and X is O, NH and or S, Y is SO ₃ ^-, OSO ₃ ^-, or CO ₂ ^- a).

<11> The composite semipermeable membrane according to any one of <1> to <10>, wherein the covalent bond is an amide bond.

(A) forming a crosslinked polyamide on a support membrane comprising a substrate and a porous support layer; and

(b) A step of covalently bonding a hydrophilic polymer having a negatively charged functional group and a negatively charged functional group to the crosslinked polyamide obtained in (a) above.

Method for producing a composite semipermeable membrane having a.

When the composite semipermeable membrane of the present invention satisfies the condition (A), the separation functional layer can maintain a sufficient hydration structure even under high salt concentration, and as a result, the composite semipermeable membrane of the present invention exhibits excellent fouling resistance.

In addition, by satisfying the above condition (B), peeling from the separation functional layer of the hydrophilic polymer during operation or washing can be suppressed, and excellent fouling resistance can be maintained for a long time.

1. Composite semipermeable membrane

The composite semipermeable membrane of the present invention comprises a support membrane comprising a substrate and a porous support layer, and a separation functional layer comprising a crosslinked polyamide (hereinafter, simply referred to as "polyamide") and a hydrophilic polymer provided on the porous support layer. Equipped.

(1-1) Separation Functional Layer

The separation functional layer is a layer that is responsible for the separation function of the solute in the composite semipermeable membrane. The composition such as the composition and the thickness of the separation functional layer is set in accordance with the purpose of use of the composite semipermeable membrane.

The separation functional layer specifically includes a crosslinked polyamide and a hydrophilic polymer.

Crosslinked polyamide is obtained by interfacial polycondensation of a polyfunctional amine and a polyfunctional acid halide.

The polyfunctional amine is preferably at least one amine selected from aromatic polyfunctional amines and aliphatic polyfunctional amines.

An aromatic polyfunctional amine is an aromatic amine which has two or more amino groups in 1 molecule, and although it does not specifically limit, metaphenylenediamine, paraphenylenediamine, 1,3,5-triaminobenzene, etc. are illustrated. In addition, as the N-alkylate, N, N-dimethylmethphenylenediamine, N, N-diethyl methphenylenediamine, N, N-dimethylparaphenylenediamine, N, N-diethylparaphenylenediamine Etc. are illustrated.

From the stability of performance expression, in particular, metaphenylenediamine (henceforth "m-PDA") or 1,3,5-triaminobenzene is preferable.

In addition, an aliphatic polyfunctional amine is an aliphatic amine which has two or more amino groups in 1 molecule, Preferably it is a piperazine-type amine and its derivative (s).

For example, piperazine, 2,5-dimethylpiperazine, 2-methylpiperazine, 2,6-dimethylpiperazine, 2,3,5-trimethylpiperazine, 2,5-diethylpiperazine, 2, 3,5-triethylpiperazine, 2-n-propylpiperazine, 2,5-di-n-butylpiperazine, ethylenediamine and the like are exemplified.

In particular from the stability of the performance expression piperazine or 2,5-dimethylpiperazine is preferred.

These polyfunctional amines may be used individually by 1 type, and may use 2 or more types as a mixture.

The polyfunctional acid halide is an acid halide having two or more halogenated carbonyl groups in one molecule, and the polyfunctional acid halide is not particularly limited as long as it provides a polyamide by reaction with the polyfunctional amine.

Examples of polyfunctional acid halides include oxalic acid, malonic acid, maleic acid, fumaric acid, glutaric acid, 1,3,5-cyclohexanetricarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4 -Cyclohexanedicarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid Halides, such as an acid, can be used. Among acid halides, acid chlorides are preferable, and trimesic acid chloride which is an acid halide of 1,3,5-benzenetricarboxylic acid (hereinafter, in view of economical efficiency, ease of availability, ease of handling, and reactivity) is particularly preferred. And "TMC" are preferred.

The said polyfunctional acid halide may be used individually by 1 type, and may use 2 or more types as a mixture.

The said polyamide has an amide group derived from the polymerization reaction of a polyfunctional amine and a polyfunctional acid halide, the amino group derived from an unreacted terminal functional group, and a carboxyl group. These functional groups affect the water permeation performance and the salt removal rate of the composite semipermeable membrane.

When the chemical treatment is performed after the polyamide is formed, the functional group in the polyamide can be converted or a new functional group can be introduced into the polyamide, thereby improving the permeation amount and the salt removal rate of the composite semipermeable membrane. Examples of the functional group to be introduced include alkyl groups, alkenyl groups, alkynyl groups, halogen groups, hydroxyl groups, amino groups, carboxyl groups, ether groups, thioether groups, ester groups, aldehyde groups, nitro groups, nitroso groups, nitrile groups, and azo groups.

For example, introducing an azo group into polyamide is preferable because the salt removal rate is improved. It is preferable that an azo group is introduce | transduced so that ratio of (mol equivalent amount of azo group) / (mol equivalent amount of an amide group) in polyamide may be 0.1 or more and 1.0 or less. High salt removal rate can be obtained because this ratio is 0.1 or more and 1.0 or less.

The functional group ratio "(molar equivalent of amino group) / (molar equivalent of amide group)" in the separation functional layer is related to the durability of the composite semipermeable membrane, and this "(molar equivalent of amino group) / (molar equivalent of amide group)" It is preferable to convert an amino group into another functional group so that the ratio of the amino group represented by the thing may be 0.18 or less. If the amino group ratio is 0.18 or less, the fastness of the layer is increased to improve the durability of the composite semipermeable membrane.

The functional group amount in these polyamides can be calculated | required, for example by ¹³ C solid NMR measurement. Specifically, the substrate is peeled off from the composite semipermeable membrane to obtain a separation functional layer and a porous support layer, and then the porous support layer is dissolved and removed to obtain a separation functional layer. The obtained separated functional layer is subjected to DD / MAS- ¹³ C solid NMR measurement to calculate the peak integrated value of the carbon atoms to which each functional group is bonded. Each functional group can be identified from this integrated value.

A hydrophilic polymer is a polymer which melt | dissolves 0.5g or more with respect to 1L of water on 25 degreeC conditions. The hydrophilic polymer can suppress that contamination adheres to the separation functional layer by its hydration structure. Fouling inhibition by the hydration structure is effective against any contamination of nonionic, cationic and anionic.

In addition, since the hydrophilic polymer is present on the surface of the separation functional layer, contamination is more likely to adhere to the hydrophilic polymer than polyamide. That is, even if contamination adheres to the surface of the separation functional layer, for example, it is considered that the contamination adheres to a position spaced apart from the polyamide by the hydrophilic polymer. Therefore, the deterioration of the performance of the separator is suppressed low.

From the above, the hydrophilic polymer is preferably present on the surface of the separation functional layer. In other words, it is preferable that a separation functional layer is equipped with the 1st layer which has polyamide as a main component, and the 2nd layer which has a hydrophilic polymer as a main component, and a 1st layer is arrange | positioned at the porous support layer side.

In addition, the hydrophilic polymer includes both a functional group having a positive charge and a functional group having a negative charge. In addition, the hydrophilic polymer is negatively charged.

In the present invention, the functional group having a charge includes a functional group having a charge by flotonation or deprotonation in water. Below, the valence of the charge in "the functional group which has a charge" is not specifically limited, It is preferable that it is monovalent.

The functional group having a positive charge is a functional group ionic due to the loss of the former, and examples thereof include ammonium, pyrrolidinium, pyridinium, imidazolium, sulfonium, and phosphonium. In addition, the functional group which has negative charge is an ionic functional group by the excess of an electron, and a carboxy group, a phosphonic acid group, a sulfonic acid group, a sulfuric acid group, a phosphoric acid group, and a phosphate ester group are mentioned.

Since the hydrophilic polymer includes both a positively charged functional group and a negatively charged functional group, since the positive and negative charges move to cancel each other's charges, the charged strength of the hydrophilic polymer is reduced, and the strength that the hydrated water is bound to the hydrophilic polymer. Becomes smaller. As a result, the exchange rate of hydrated water becomes large so that adhesion of a foulant can be suppressed. Moreover, it is hard to be influenced by the ionic strength of the water to be treated, and can exhibit excellent fouling resistance even to the water to be treated with high salt concentration such as seawater.

Here, the fouling resistance may include any of suppressing fouling and suppressing a decrease in performance even if fouling occurs.

In addition, in the hydrophilic polymer, since it is positively or negatively charged and does not completely cancel the charge, in addition to the above advantages, it can have a high hydrophilicity and a hydration amount, and exhibits excellent fouling resistance. In the present invention, being positively or negatively charged indicates that the total amount of positive charges and the total amount of negative charges are different. That is, when the number of positive charges in the whole hydrophilic polymer is greater than the number of negative charges, the "hydrophilic polymer is positively charged", and when the number of negative charges in the whole hydrophilic polymer is larger than the number of positive charges, the "hydrophilic polymer is negative Charge it.

Specifically, if the functional group having a charge included in the hydrophilic polymer is only a monovalent functional group, the functional group having a positive charge and the functional group having a negative charge are different, so that the hydrophilic polymer is positively or negatively charged.

The hydrophilic polymer of the present invention is negatively charged. As the hydrophilic polymer is negatively charged, more excellent fouling resistance can be exhibited with respect to contaminants containing organic acids such as humus.

In a hydrophilic polymer, it is preferable that ratio (N1 / N2) of the number N1 of functional groups which have a positive charge, and the number N2 of functional groups which have a negative charge is 15/85 or more and 45/55 or less. More preferably, (N1 / N2) is 20/80 or more and 40/60 or less. When the ratio of functional groups is 15/85 or more, the effect of improving the exchange rate of hydrated water due to charge offset can be sufficiently obtained, and when it is 45/55 or less, it is possible to have a higher amount of hydrated water.

Moreover, it is preferable that the charge density of a hydrophilic polymer is 7.5 mmol / g or more and 10.5 mmol / g or less. Charge density is the molar amount of the functional group which has a charge per unit mass. The charge density is 7.5 mmol / g or more, and may have a higher amount of hydration. When the charge density is 10.5 mmol / g or less, the binding of the hydrated water by the hydrophilic polymer is weakened, and the effect of improving the exchange rate of the hydrated water can be further enhanced. More preferably, the charge density is 8.0 mmol / g or more, and 10.0 mmol / g or less.

When the hydrophilic polymer has the composition described above, the hydrophilic water of the hydrophilic polymer can suppress hydrophobic interaction and suppress adhesion of the hydrophobic molecule, and can exhibit excellent fouling resistance to the charged material.

As described above, since the hydrophilic polymer of the present invention is negatively charged, the negative charge density is larger in the hydrophilic polymer than in the positive charge density. Moreover, it is more preferable if negative charge density exists in the range of 4.5 mmol / g or more and 8.0 mmol / g or less.

These hydrophilic polymers are preferably monomer polymers having an ethylenically unsaturated group from the chemical stability of the polymer.

The hydrophilic polymer includes a functional group having a positive charge and a functional group having a negative charge as described above, but includes a functional group having a charged charge, and the charge includes a monomer P having a negative charge, a functional group having a positive charge, and a functional group having a negative charge. It is preferable that it is a copolymer of monomer Q to be mentioned. That is, monomer P contains the functional group which has only negative charge as a charge, and does not contain the functional group which has a positive charge.

As described above, the hydrophilic polymer includes both functional groups having positive charges and functional groups having negative charges, so that the charge strength of the hydrophilic polymer can be reduced, and the bond to the hydrophilic polymer of hydrated water is reduced. The effect of reducing the charge strength depends on the distance of the sensory period, and the shorter the distance, the greater the effect. Therefore, in a hydrophilic polymer, it is more preferable to exist in the vicinity with the functional group which has a positive charge, and the functional group which has a negative charge. Furthermore, it is preferable to have a functional group having a positive charge and a functional group having a negative charge (monomer Q) in the same monomer because these functional groups are arranged in a short distance. In addition, as described above, it is also preferable to copolymerize a monomer Q including both of a positively charged functional group and a negatively charged functional group in combination with another monomer P having a functional group having only negative charges.

The following are illustrated as a monomer which has a carboxyl group in the monomer which has the said ethylenically unsaturated group. Maleic acid, maleic anhydride, acrylic acid, methacrylic acid, itaconic acid, 2- (hydroxymethyl) acrylic acid, 4- (meth) acryloyloxyethyl trimellitic acid and the corresponding anhydrides, 10-methacryloyloxyde Silalonic acid, N- (2-hydroxy-3-methacryloyloxypropyl) -N-phenylglycine and 4-vinylbenzoic acid; acrylic acid and methacrylic acid from the viewpoint of versatility and copolymerizability And maleic acid are preferable, and as polymer P, at least one selected from the group consisting of acrylic acid, methacrylic acid and maleic acid is preferable.

Examples of the monomer having a phosphonic acid group in the monomer having an ethylenically unsaturated group include vinylphosphonic acid, 4-vinylphenylphosphonic acid, 4-vinylbenzylphosphonic acid, 2-methacryloyloxyethylphosphonic acid, and 2-methacrylamide. Ethylphosphonic acid, 4-methacrylamide-4-methyl-phenyl-phosphonic acid, 2- [4- (dihydroxyphosphoryl) -2-oxa-butyl] -acrylic acid and 2- [2-dihydroxyphosph Foryl) -ethoxymethyl] -acrylic acid-2,4,6-trimethyl-phenylester is illustrated.

Examples of the monomer having a phosphate ester group in the monomer having an ethylenically unsaturated group include 2-methacryloyloxypropyl monohydrogen phosphate, 2-methacryloyloxypropyl dihydrogen phosphate and 2-methacryloyloxyethyl monohydrogen phosphate. And 2-methacryloyloxyethyl dihydrogen phosphate, 2-methacryloyloxyethyl-phenyl-hydrogen phosphate, dipentaerythritol-pentamethacryloyloxyphosphate, 10-methacryloyloxydecyl-2 Hydrogen phosphate, dipentaerythritolpentamethacryloyloxyphosphate, mono- (1-acryloyl-piperidin-4-yl) -ester, 6- (methacrylamide) hexyl dihydrogenphosphate and 1, 3-bis- (N-acryloyl-N-propyl-amino) -propan-2-yl-2 hydrogenphosphate is illustrated.

Examples of the monomer having a sulfonic acid group in the monomer having an ethylenically unsaturated group include vinylsulfonic acid, 4-vinylphenylsulfonic acid or 3- (methacrylamide) propylsulfonic acid.

In the monomer which has the said ethylenically unsaturated group, as a monomer Q containing both the functional group which has a positive charge, and the functional group which has a negative charge, the compound represented by following formula (1) or the compound represented by Formula (2) is illustrated. These compounds are examples of the compound which has one functional group which has one negative charge, and each functional group which has one positive charge.

The formula (1) and in formula (2), R ¹ is H or CH _3, and, R ^2, R ^3, R ⁶ and R ⁷ are each independently, an alkylene group having 1 to 5 carbon atoms, or C 1 -C 5 is an oxyalkylene group, R ⁴ , R ⁵ , R ⁸ , R ⁹ and R ¹⁰ are each independently an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, and X is O, NH or and S, Y is SO ₃ ^-, OSO ₃ ^-, or CO ₂ ^- a.

More specifically, the compound is [2- (methacryloyloxy) ethyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [2- (methacryloyloxy) ethyl] -dimethyl -(3-sulfopropyl) -ammonium hydroxide, [2- (methacryloyloxy) ethyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [2- (methacryloyloxy) Ethyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide, [2- (acryloyloxy) ethyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [2- (acryloyl jade Ethyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [2- (acryloyloxy) ethyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [2- (acrylic) Royloxy) ethyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide, [3- (methacryloyloxy) propyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [3 -(Methacryloyloxy) propyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [3- (methacryloyloxy) propyl] -dimethyl -(4-sulfobutyl) -ammonium hydroxide, [3- (methacryloyloxy) propyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide, [3- (acryloyloxy) propyl ] -Dimethyl- (2-sulfoethyl) -ammonium hydroxide, [3- (acryloyloxy) propyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [3- (acryloyloxy ) Propyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [3- (acryloyloxy) propyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide, [4- (methacryl Royloxy) butyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [4- (methacryloyloxy) butyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [4 -(Methacryloyloxy) butyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [4- (methacryloyloxy) butyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide Seed, [4- (acryloyloxy) butyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [4- (acryloyloxy) butyl] -dimethyl- (3-sul Popropyl) -ammonium hydroxide, [4- (acryloyloxy) butyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [4- (acryloyloxy) butyl] -dimethyl- ( 5-sulfopentyl) -ammonium hydroxide, [2- (methacryloylamino) ethyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [2- (methacryloylamino) ethyl] -Dimethyl- (3-sulfopropyl) -ammonium hydroxide, [2- (methacryloylamino) ethyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [2- (methacryloyl Amino) ethyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide, [2- (acryloylamino) ethyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [2- (acrylic Loylamino) ethyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [2- (acryloylamino) ethyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [2- (Acryloylamino) ethyl] -dimethyl- (5-sulphopentyl) -ammonium hydroxide, [3- (methacryloylamino) propyl] -di Methyl- (2-sulfoethyl) -ammonium hydroxide, [3- (methacryloylamino) propyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [3- (methacryloylamino ) Propyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [3- (methacryloylamino) propyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide, [3- (acrylic Loylamino) propyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [3- (acryloylamino) propyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [3- (Acryloylamino) propyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [3- (acryloylamino) propyl] -dimethyl- (5-sulfopentyl) -ammonium hydroxide, [ 4- (Methacryloylamino) butyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [4- (methacryloylamino) butyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide Roxoxide, [4- (methacryloylamino) butyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide, [4- ( Methacryloylamino) butyl] -dimethyl- (5-sulphopentyl) -ammonium hydroxide, [4- (acryloylamino) butyl] -dimethyl- (2-sulfoethyl) -ammonium hydroxide, [ 4- (Acryloylamino) butyl] -dimethyl- (3-sulfopropyl) -ammonium hydroxide, [4- (acryloylamino) butyl] -dimethyl- (4-sulfobutyl) -ammonium hydroxide , [4- (acryloylamino) butyl] -dimethyl- (5-sulphopentyl) -ammonium hydroxide, 2- (methacryloyloxy) ethyl2- (trimethylammonio) ethylphosphate, 3- ( Methacryloyloxy) propyl2- (trimethylammonio) ethylphosphate, 4- (methacryloyloxy) butyl2- (trimethylammonio) ethylphosphate, 5- (methacryloyloxy) pentyl2- ( Trimethylammonio) ethylphosphate, 2- (methacryloylamino) ethyl2- (trimethylammonio) ethylphosphate, 3- (methacryloylamino) propyl2- (trimethylammonio) ethylphosphate, 4- ( Methacryloyl No) Butyl 2- (trimethylammonio) ethyl phosphate, 5- (methacryloylamino) pentyl2- (trimethylammonio) ethyl phosphate, 2- (acryloyloxy) ethyl2- (trimethylammonio) ethyl Phosphate, 3- (acryloyloxy) propyl2- (trimethylammonio) ethylphosphate, 4- (acryloyloxy) butyl2- (trimethylammonio) ethylphosphate, 5- (acryloyloxy) pentyl2 -(Trimethylammonio) ethylphosphate, 2- (methacryloyloxy) ethyl3- (trimethylammonio) propylphosphate, 3- (methacryloyloxy) propyl3- (trimethylammonio) propylphosphate, 4 -(Methacryloyloxy) butyl3- (trimethylammonio) propylphosphate, 5- (methacryloyloxy) pentyl3- (trimethylammonio) propylphosphate, 2- (methacryloylamino) ethyl3 -(Trimethylammonio) propylphosphate, 3- (methacryloylamino) propyl3- (trimethylammonio) prop Philphosphate, 4- (methacryloylamino) butyl3- (trimethylammonio) propylphosphate, 5- (methacryloylamino) pentyl3- (trimethylammonio) propylphosphate, 2- (acryloyloxy ) Ethyl 3- (trimethylammonio) propyl phosphate, 3- (acryloyloxy) propyl 3- (trimethylammonio) propyl phosphate, 4- (acryloyloxy) butyl 3- (trimethylammonio) propyl phosphate, 5- (acryloyloxy) pentyl3- (trimethylammonio) propylphosphate, 2- (methacryloyloxy) ethyl4- (trimethylammonio) butylphosphate, 3- (methacryloyloxy) propyl4 -(Trimethylammonio) butylphosphate, 4- (methacryloyloxy) butyl 4- (trimethylammonio) butylphosphate, 5- (methacryloyloxy) pentyl4- (trimethylammonio) butylphosphate, 2 -(Methacryloylamino) ethyl4- (trimethylammonio) butylphosphate, 3- (methacryloyl Mino) propyl4- (trimethylammonio) butylphosphate, 4- (methacryloylamino) butyl4- (trimethylammonio) butylphosphate, 5- (methacryloylamino) pentyl4- (trimethylammonio) Butyl phosphate, 2- (acryloyloxy) ethyl4- (trimethylammonio) butyl phosphate, 3- (acryloyloxy) propyl4- (trimethylammonio) butyl phosphate, 4- (acryloyloxy) butyl 4- (trimethylammonio) butylphosphate, 5- (acryloyloxy) pentyl4- (trimethylammonio) butylphosphate, 2-{[2- (methacryloyloxy) ethyl] dimethylammonio} ethano , 3-{[2- (methacryloyloxy) ethyl] dimethylammonio} propanoate, 4-{[2- (methacryloyloxy) ethyl] dimethylammonio} butanoate, 5- {[2- (methacryloyloxy) ethyl] dimethylammonio} pentanoate, 2-{[2- (acryloyloxy) ethyl] dimethylammonio} ethanoate, 3-{[2- ( With acrylic Oxy) ethyl] dimethylammonio} propanoate, 4-{[2- (acryloyloxy) ethyl] dimethylammonio} butanoate, 5-{[2- (acryloyloxy) ethyl] dimethylammoni O} pentanoate, 2-{[3- (methacryloyloxy) propyl] dimethylammonio} ethanoate, 3-{[3- (methacryloyloxy) propyl] dimethylammonio} propano , 4-{[3- (methacryloyloxy) propyl] dimethylammonio} butanoate, 5-{[3- (methacryloyloxy) propyl] dimethylammonio} pentanoate, 2- {[3- (acryloyloxy) propyl] dimethylammonio} ethanoate, 3-{[3- (acryloyloxy) propyl] dimethylammonio} propanoate, 4-{[3- (acrylic Royloxy) propyl] dimethylammonio} butanoate, 5-{[3- (acryloyloxy) propyl] dimethylammonio} pentanoate, 2-{[4- (methacryloyloxy) butyl ] Dimethylammonio} ethanoate, 3-{[4- (methacryloyloxy) moiety ] Dimethylammonio} propanoate, 4-{[4- (methacryloyloxy) butyl] dimethylammonio} butanoate, 5-{[4- (methacryloyloxy) butyl] dimethylammonio } Pentanoate, 2-{[4- (acryloyloxy) butyl] dimethylammonio} ethanoate, 3-{[4- (acryloyloxy) butyl] dimethylammonio} propanoate, 4 -{[4- (acryloyloxy) butyl] dimethylammonio} butanoate, 5-{[4- (acryloyloxy) butyl] dimethylammonio} pentanoate, 2-{[5- ( Methacryloyloxy) pentyl] dimethylammonio} ethanoate, 3-{[5- (methacryloyloxy) pentyl] dimethylammonio} propanoate, 4-{[5- (methacryloyl jade Pentyl] dimethylammonio} butanoate, 5-{[5- (methacryloyloxy) pentyl] dimethylammonio} pentanoate, 2-{[5- (acryloyloxy) pentyl] dimethyl Ammonio} ethanoate, 3-{[5- (acryloyloxy) pentyl] dimethylammonio} propano , 4-{[5- (acryloyloxy) pentyl] dimethylammonio} butanoate, 5-{[5- (acryloyloxy) pentyl] dimethylammonio} pentanoate, 2-{[ 2- (methacryloylamino) ethyl] dimethylammonio} ethanoate, 3-{[2- (methacryloylamino) ethyl] dimethylammonio} propanoate, 4-{[2- (meta Chryloylamino) ethyl] dimethylammonio} butanoate, 5-{[2- (methacryloylamino) ethyl] dimethylammonio} pentanoate, 2-{[2- (acryloylamino) Ethyl] dimethylammonio} ethanoate, 3-{[2- (acryloylamino) ethyl] dimethylammonio} propanoate, 4-{[2- (acryloylamino) ethyl] dimethylammonio} Butanoate, 5-{[2- (acryloylamino) ethyl] dimethylammonio} pentanoate, 2-{[3- (methacryloylamino) propyl] dimethylammonio} ethanoate, 3 -{[3- (methacryloylamino) propyl] dimethylammonio} propano , 4-{[3- (methacryloylamino) propyl] dimethylammonio} butanoate, 5-{[3- (methacryloylamino) propyl] dimethylammonio} pentanoate, 2- {[3- (acryloylamino) propyl] dimethylammonio} ethanoate, 3-{[3- (acryloylamino) propyl] dimethylammonio} propanoate, 4-{[3- (acrylic Loylamino) propyl] dimethylammonio} butanoate, 5-{[3- (acryloylamino) propyl] dimethylammonio} pentanoate, 2-{[4- (methacryloylamino) butyl ] Dimethylammonio} ethanoate, 3-{[4- (methacryloylamino) butyl] dimethylammonio} propanoate, 4-{[4- (methacryloylamino) butyl] dimethylammonio } Butanoate, 5-{[4- (methacryloylamino) butyl] dimethylammonio} pentanoate, 2-{[4- (acryloylamino) butyl] dimethylammonio} ethanoate, 3-{[4- (acryloylamino) butyl] dimethylammoni Oh} propanoate, 4-{[4- (acryloylamino) butyl] dimethylammonio} butanoate, 5-{[4- (acryloylamino) butyl] dimethylammonio} pentanoate, 2-{[5- (methacryloylamino) pentyl] dimethylammonio} ethanoate, 3-{[5- (methacryloylamino) pentyl] dimethylammonio} propanoate, 4-{[ 5- (methacryloylamino) pentyl] dimethylammonio} butanoate, 5-{[5- (methacryloylamino) pentyl] dimethylammonio} pentanoate, 2-{[5- (acrylic Loylamino) pentyl] dimethylammonio} ethanoate, 3-{[5- (acryloylamino) pentyl] dimethylammonio} propanoate, 4-{[5- (acryloylamino) pentyl] It is preferred to include one or more selected from the group consisting of dimethyl ammonio} butanoate and 5-{[5- (acryloylamino) pentyl] dimethylammonio} pentanoate, but the present invention is not limited thereto. no.

The ratio (PN: QN) of the number (molar number) (PN) of the monomer units derived from the monomer P and the number (molar number) (QN) of the monomer units derived from the monomer Q is not limited to specific numerical values, It is preferable to exist in the range of 80: 20-20: 80. When the molar ratio of the monomer unit is in the range of 80:20 to 20:80, it has a higher amount of hydrated water and the effect of improving the exchange rate of hydrated water by charge offset can be sufficiently obtained. In addition to this condition, as described above, the ratio between the number of functional groups having positive charges and the number of functional groups having negative charges is more preferably within a range of 15:85 or more and 45:55 or less.

The ratio between the number of functional groups having positive charges and the number of functional groups having negative charges is calculated from the monomer ratio when synthesizing the hydrophilic polymer, and, for example, X-ray photoelectron spectroscopy (XPS) is used for the surface element composition and chemistry. It can also be calculated by measuring the binding state. At this time, when the measurement depth is deep, the composition of the polyamide in the separation functional layer is affected, and therefore, it is preferable to measure the outermost surface by an angular decomposition method in which the sample is inclined. In addition, depending on the kind of functional group, you may convert into another functional group by the chemical modification method, and measure it. For example, by reacting a carboxyl group with trifluoroethanol in the presence of a condensing agent, the number of functional groups can be estimated from the abundance ratio of the fluorine atom.

The hydrophilic polymer may be a binary copolymer of a monomer P containing the functional group having a negative charge and a monomer Q containing both a functional group having a positive charge and a functional group having a negative charge, but may be copolymerized with another monomer according to the purpose. do. Examples of the copolymerization component include vinylpyrrolidone, vinyl alcohol, vinyl acetate, ethylene glycol, propylene glycol, polyethylene glycol (meth) acrylate, block copolymers of these hydrophilic polymers and hydrophobic polymers, graft copolymers, random copolymers, and the like. Can be mentioned. Among the above hydrophilic polymers, vinylpyrrolidone, vinyl alcohol and vinyl acetate are preferable from the viewpoint of ease of copolymerization and reduction of adhesion to foulants.

It is preferable that the weight average molecular weights of the hydrophilic polymer of this invention are 2,000 or more and 1,500,000 or less. The weight average molecular weight is 2,000 or more, it can have a layer of more sufficient hydration water, and it is 1,500,000 or less, can suppress the increase of the resistance of the water which permeate | transmits a separation functional layer, and can maintain a higher permeation flow rate. More preferably, it is 3,000-1,200,000, More preferably, it is 5,000-1,000,000.

Hydrophilic polymers are covalently introduced into the crosslinked polyamide. When the hydrophilic polymer is attached to the membrane by electrostatic interaction, for example, the interaction between the hydrophilic polymer and the membrane is inhibited by the negatively charged foulant, so that the hydrophilic polymer is peeled off from the membrane. Suppressed.

As the covalent bonds, in addition to carbon-carbon bonds, ether bonds, ester bonds, amide bonds, imide bonds, urethane bonds, carbonate ester bonds, phosphate ester bonds, sulfate ester bonds, nitrate ester bonds, thioether bonds, thioester bonds, and sulfides A phenyl bond is mentioned, It is especially preferable that it is introduce | transduced into an amide bond.

Specifically, it is preferable that a hydrophilic polymer is introduced into the polyamide which is the main component of the separation functional layer via an amide bond via a terminal carboxylic acid or an amino group. That is, it is preferable that the hydrophilic polymer contained in the 2nd layer mentioned above is amide-bonded with the polyamide contained in a 1st layer. In addition, if a series of measurement operations of detecting the hydrophilic polymer on the surface of the separation functional layer, etching and then detecting the hydrophilic polymer is repeated, it is observed that a large amount of hydrophilic polymer exists on the surface of the separation functional layer. It is possible to confirm.

Since the hydrophilic polymer is introduced into the separation functional layer by the amide bond, the composite semipermeable membrane (separation membrane) can express high fouling resistance. In the case where the hydrophilic polymer is introduced by weak bonding or interaction, it is not preferable because the hydrophilic polymer is easily detached by chemical liquid washing or the like.

It is preferable that the square average surface roughness (henceforth "Rms") of a separation functional layer surface is 60 nm or more. When the root mean square roughness is 60 nm or more, the surface area of the separation functional layer is increased, and the amount of permeate is increased. On the other hand, when the root mean square roughness is less than 60 nm, the amount of permeate is lowered.

In addition, a root mean square roughness can be measured with atomic force microscope (henceforth "AFM"). The root mean square roughness is the square root of the average of the squares of the deviations from the reference plane to the specified plane. Here, the measurement surface refers to the surface indicated by the entire measurement data, and the designation surface is a surface to be subjected to roughness measurement, and refers to a specific portion designated by the clip among the measurement surfaces, and the reference surface is Z0 when the average value of the height of the designation surface is Z0. Refers to the plane represented by Z0. AFM can use NanoScope IIIa by a digital instruments company, for example.

The square average surface roughness of the surface of the separation functional layer can be controlled in accordance with the monomer concentration and temperature when forming the separation functional layer by interfacial polycondensation. For example, if the temperature at the time of interfacial polycondensation is low, the square mean surface roughness is small, and if the temperature is high, the square mean surface roughness is large. When the hydrophilic polymer is modified on the surface of the separation functional layer, since the square average surface roughness becomes small when the hydrophilic polymer layer is thick, it is preferable to modify the square average surface roughness to be 60 nm or more.

When the bubbles contact angle of the air bubble contact angle of the aqueous solution of pH3 of the separation function layer surface during θ _A, an aqueous solution of pH11 when θ _B La, 150 ° <θ _A also is preferably in the range of θ _B <180 ° . By being in the said range, it can have the outstanding low fouling property in a wide pH range.

Moreover, it is preferable that ((theta) _B- (theta) _A )> 5 degrees. There is a method for recovering the permeate amount by washing with a reverse osmosis membrane whose permeate amount is lowered due to fouling or the like by using a chemical such as an acid or alkali. Can improve. More preferably, (θ _B -θ _A )> 10 °.

(1-2) support film

The support membrane is for imparting strength to the separation functional layer, and itself does not substantially have separation performance such as ions. The support membrane contains a base material and a porous support layer.

The size and distribution of the pores in the support membrane are not particularly limited, but for example, uniform and fine pores, or gradually larger micropores from the surface on the side where the separating function layer is formed to the other side, and furthermore, the separating function layer The support film | membrane in which the magnitude | size of the micropore in the surface of this side formed is 0.1 nm or more and 100 nm or less is preferable.

The support membrane is obtained by, for example, casting a high molecular polymer on a substrate and forming a porous support layer on the substrate. The material used for a support film and its shape are not specifically limited.

As a base material, the fabric containing at least 1 sort (s) chosen from polyester and aromatic polyamide is illustrated. Particular preference is given to using polyesters which are mechanically and thermally stable.

As a fabric used for a base material, a long fiber nonwoven fabric and a short fiber nonwoven fabric can be used preferably. When the solution of the polymer polymer is softened on the substrate, it is excellent in that it is not overturned by over-penetration, the substrate and the porous support layer are peeled off, and further, defects such as unevenness of the membrane and pinholes are caused by fluffing of the substrate. Since a film forming property is requested | required, a long fiber nonwoven fabric can be used more preferably.

As a long fiber nonwoven fabric, the long fiber nonwoven fabric etc. which consist of thermoplastic continuous filaments are mentioned. Since the base material includes a long fiber nonwoven fabric, it is possible to suppress nonuniformity in polymer solution casting caused by fluffing and a film defect caused when a short fiber nonwoven fabric is used. In addition, in the process of continuously forming a composite semipermeable membrane, it is preferable to use the long fiber nonwoven fabric which is excellent in dimensional stability also as a base material from the point which tension | tensile_strength is applied to the film forming direction of a base material.

In particular, the orientation of the fibers in the nonwoven fabric disposed on the opposite side of the porous support layer of the substrate is preferable because the orientation of the fibers is longitudinally aligned with the film forming direction, so that the strength of the substrate can be maintained and film breakage can be prevented. Here, a vertical orientation means that the orientation direction of a fiber is parallel to a film forming direction. Conversely, when the orientation direction of a fiber is orthogonal to a film forming direction, it is called horizontal orientation.

As a fiber orientation degree of a nonwoven fabric base material, it is preferable that the orientation degree of the fiber in the opposite side to a porous support layer is 0 degrees or more and 25 degrees or less. A fiber orientation degree is an index which shows the fiber direction of the nonwoven fabric base material which comprises a support film here, The film forming direction at the time of continuous film forming is called 0 degree, The direction perpendicular to the film forming direction, ie, the width direction of a nonwoven fabric base material made 90 degree. The thing of the average angle of the fiber which comprises a nonwoven fabric base material at the time of is said. Therefore, the closer the fiber orientation is to 0 °, the longer the longitudinal orientation, and the closer to 90 °, the horizontal orientation.

Although the heating process is included in the manufacturing process of a composite semipermeable membrane, and the manufacturing process of an element, the phenomenon which a support membrane or a composite semipermeable membrane shrink | contracts by heating occurs. Especially in continuous film forming, since tension is not provided in the width direction, it tends to shrink in the width direction. Since shrinkage of a support membrane or a composite semipermeable membrane causes problems such as dimensional stability, a substrate having a small thermal dimensional change rate is desired.

When the orientation difference between the fibers disposed on the opposite side of the porous support layer and the fibers disposed on the porous support layer side in the nonwoven fabric substrate is 10 ° or more and 90 ° or less, the change in the width direction due to heat is preferable.

It is preferable that the air permeability of a base material is 2.0 cc / cm <2> / sec or more. If the air permeability is within this range, the permeation amount of the composite semipermeable membrane is higher. This is because in the step of forming the support membrane, when the polymer polymer is flexible on the substrate and immersed in the coagulation bath, the non-solvent substitution rate from the substrate side is increased so that the internal structure of the porous support layer changes, and the subsequent separation functional layer is It is considered that it affects the retention amount and the diffusion rate of the monomer in the forming step.

In addition, air permeability can be measured with a plastic-type tester based on JISL1096 (2010). For example, a base material is cut out to the magnitude | size of 200 mm x 200 mm, and it is set as a sample. This sample is installed in a fragrance tester, and the suction pan and the air hole are adjusted so that the inclined barometer has a pressure of 125 kPa, the amount of air passing through the substrate from the pressure indicated by the vertical barometer and the type of air hole used, That is, aeration can be calculated. The plastic type tester can use KES-F8-AP1 grade | etc., Made by Kato Tech Corporation.

Moreover, it is preferable that the thickness of a base material exists in the range of 10 micrometers or more and 200 micrometers or less, More preferably, it exists in the range of 30 micrometers or more and 120 micrometers or less.

The material of the porous support layer may be a homopolymer such as polysulfone, polyether sulfone, polyamide, polyester, cellulose polymer, vinyl polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfone, polyphenylene oxide, or the like. The copolymers may be used alone or in combination.

As the cellulose polymer, polyethylene, polypropylene, polyvinyl chloride, polyacrylonitrile or the like can be used as the vinyl polymer such as cellulose acetate or cellulose nitrate.

Among them, homopolymers or copolymers such as polysulfone, polyamide, polyester, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide and polyphenylene sulfide sulfone are preferable. More preferably, cellulose acetate, polysulfone, polyphenylene sulfide sulfone, or polyphenylene sulfone may be mentioned. Among these materials, polysulfone may be used in terms of high chemical, mechanical, and thermal stability and easy molding. Generally can be used.

Specifically, it is preferable to use polysulfone containing the repeating unit shown in the following formula because it is easy to control the pore diameter of the support membrane and the dimensional stability is high.

For example, the N, N-dimethylformamide (hereinafter referred to as "DMF") solution of the polysulfone is cast on a tightly woven polyester cloth or a polyester nonwoven fabric to a certain thickness, and wet-coagulated in water It is possible to obtain a supporting film having most of the surfaces having fine pores having a diameter of 10 nm or less.

The thickness of the support membrane affects the strength of the obtained composite semipermeable membrane and the packing density when the element is used as an element. In order to obtain sufficient mechanical strength and packing density, the thickness of the supporting film is preferably in the range of 30 µm or more and 300 µm or less, and more preferably in the range of 100 µm or more and 220 µm or less.

The form of a porous support layer can be observed with a scanning electron microscope, a transmission electron microscope, and an atomic microscope. For example, when observing with a scanning electron microscope, after peeling a porous support layer from a base material, this is cut | disconnected by the freezing cutting method and it is set as the sample of cross-sectional observation. This sample is coated with a thin coating of platinum or platinum-palladium or ruthenium tetrachloride, preferably ruthenium tetrachloride, and observed by high resolution field emission scanning electron microscopy (UHR-FE-SEM) at an accelerating voltage of 3 to 15 mA. As a high resolution field emission scanning electron microscope, the S-900 electron microscope etc. made by Hitachi Seisakusho Co., etc. can be used.

The support membrane used for this invention can also be selected from various commercial materials, such as "Millipore filter-VSWP" by Millipore company, "Ultra filter UK10" (brand name) by Toyo Rossi Co., Ltd., and "Office of sale." It can also manufacture according to the method etc. which were described in lean water research and development progress report "No.359 (1968).

It is preferable that the thickness of a porous support layer exists in the range of 20 micrometers or more and 100 micrometers or less. Since the porous support layer has a thickness of 20 µm or more, good pressure resistance can be obtained, and a uniform support membrane without defects can be obtained. Thus, the composite semipermeable membrane having such a porous support layer can exhibit better salt removal performance. When the thickness of the porous support layer exceeds 100 µm, the residual amount of the unreacted material at the time of manufacture increases, whereby the amount of permeated water decreases and the chemical resistance may decrease.

In addition, the thickness of a base material and the thickness of a composite semipermeable membrane can be measured with a digital thickness meter. In addition, since the thickness of the separation functional layer is very thin as compared with the supporting membrane, the thickness of the composite semipermeable membrane can be regarded as the thickness of the supporting membrane. Therefore, by measuring the thickness of the composite semipermeable membrane with a digital thickness meter and subtracting the thickness of the substrate from the thickness of the composite semipermeable membrane, the thickness of the porous support layer can be simply calculated. As a digital thickness measuring instrument, Ozaki Seisakusho Co., Ltd. PEACOCK etc. can be used. When using a digital thickness meter, thickness is measured about 20 places and an average value is computed.

In addition, when it is difficult to measure the thickness of a base material or the thickness of a composite semipermeable membrane with a thickness meter, you may measure with a scanning electron microscope. About one sample, thickness is calculated | required by measuring thickness from the electron micrograph of the cross-sectional observation in arbitrary five places, and calculating an average value.

2. Manufacturing Method

Next, the manufacturing method of the said composite semipermeable membrane is demonstrated. The manufacturing method includes a step of forming a supporting film and a step of forming a separation functional layer.

(2-1) Formation of Support Film

The formation process of a support film includes the process of apply | coating a polymer solution to a base material, and the process of solidifying a polymer by immersing the said base material which apply | coated the solution to the coagulation bath.

In the process of apply | coating a polymer solution to a base material, a polymer solution melt | dissolves and prepares the polymer which is a component of a porous support layer in the good solvent of this polymer.

It is preferable that the temperature of the polymer solution at the time of polymer solution application | coating is 10 degreeC or more and 60 degrees C or less when using polysulfone, for example as a polymer. If the temperature of the polymer solution is within this range, the polymer does not precipitate, and the polymer solution is solidified after sufficiently impregnating between the fibers of the substrate. As a result, the porous support layer is firmly bonded to the substrate by the anchor effect, and a good support membrane can be obtained. In addition, the preferable temperature range of a polymer solution can be suitably adjusted according to the kind of polymer to be used, desired solution viscosity, etc.

After apply | coating a polymer solution on a base material, it is preferable that time until it is immersed in a coagulation bath is 0.1 second or more and 5 second or less. If the time until immersion in a coagulation bath is this range, the organic-solvent solution containing a polymer will fully solidify after being impregnated between the fibers of a base material. Moreover, the preferable range of time until immersion in a coagulation bath can be suitably adjusted according to the kind of polymer solution to be used, desired solution viscosity, etc.

As a coagulation bath, although water is used normally, what is necessary is just to not melt | dissolve the polymer which is a component of a porous support layer. The film form of the support membrane obtained by the composition of the coagulation bath changes, and the composite semipermeable membrane obtained thereby also changes.

As for the temperature of a coagulation bath, -20 degreeC or more and 100 degrees C or less are preferable, More preferably, they are 10 degreeC or more and 50 degrees C or less. If the temperature of the coagulation bath is within this range, the vibration of the coagulation bath surface due to the thermal motion does not become severe, and the smoothness of the film surface after film formation is maintained. Moreover, if temperature is in this range, a solidification rate will be suitable and film forming property will be favorable.

Next, in order to remove the solvent which remain | survives in a film | membrane in this way, the support film obtained is hydrothermally wash | cleaned. 40 degreeC or more and 100 degrees C or less are preferable, and, as for the temperature of the hot water at this time, More preferably, they are 60 degreeC or more and 95 degrees C or less. If it is in this range, the shrinkage degree of a support membrane will not become large and a permeate amount is favorable. Moreover, a washing | cleaning effect is enough as temperature is in this range.

(2-2) Formation Process of Separation Functional Layer

Next, the formation process of the separation functional layer which comprises a composite semipermeable membrane is demonstrated. Formation process of the separation functional layer of the present invention,

(a) forming a crosslinked polyamide on a support membrane comprising a substrate and a porous support layer, and

(b) a step of covalently bonding a negatively charged hydrophilic polymer containing a functional group having a positive charge and a functional group having a negative charge to the crosslinked polyamide obtained in the above (a)

Has

It is preferable that the said process (a) is the following process (a) '.

(a) Process of forming crosslinked polyamide by performing interfacial polycondensation on the surface of a support film using the aqueous solution containing a polyfunctional amine, and the organic solvent solution containing a polyfunctional acid halide.

In addition, the formation process of a separation functional layer is further,

(c) contacting with a reagent that reacts with a crosslinked polyamide primary amino group to form a diazonium salt or derivative thereof

You may further include.

The step (b) may be after the step (a). In addition, process (c) may be performed between process (a) and (b), and may be performed after process (b).

The said process (a) forms the 1st layer which has a polyamide as a main component, and, after a process (b), the 2nd layer which has a hydrophilic polymer as a main component is formed in the surface of a 1st layer. The step (b) is a step of introducing the crosslinked polyamide and the hydrophilic polymer into a covalent bond, and since the hydrophilic polymer hardly passes through the crosslinked polyamide substantially responsible for the separation function, the surface of the first layer The second layer is formed.

In addition, the said process (c) is a process of converting an amino group into a functional group, and a process (c) is performed after a process (b), and introduces more hydrophilic polymer than a process (c) before a process (b), The fouling resistance can be improved.

In the step (a), any organic solvent that dissolves the polyfunctional acid halide may be any one that is incompatible with water, does not destroy the support membrane, and does not inhibit the formation reaction of the crosslinked polyamide.

Representative examples include halogenated hydrocarbons such as liquid hydrocarbons and trichlorotrifluoroethane. In consideration of the substance which does not destroy the ozone layer, ease of acquisition, ease of handling, and safety in handling, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, heptadecane, hexadecane, cyclooctane, Single or mixtures of ethylcyclohexane, 1-octene, 1-decene and the like are preferably used.

In an organic solvent solution containing an aqueous polyfunctional amine solution or a polyfunctional acid halide, compounds such as an acylation catalyst, a polar solvent, an acid scavenger, a surfactant, and an antioxidant, as necessary, as long as they do not interfere with the reaction between the two components. May be included.

In order to perform interfacial polycondensation on a support membrane, the support membrane surface is first coat | covered with the polyfunctional amine aqueous solution. Here, as for the density | concentration of the aqueous solution containing a polyfunctional amine, 0.1 weight% or more and 20 weight% or less are preferable, More preferably, they are 0.5 weight% or more and 15 weight% or less.

As a method for covering the surface of the support membrane with an aqueous polyfunctional amine solution, the surface of the support membrane may be uniformly and continuously covered with this aqueous solution, and a known coating means, for example, a method for coating an aqueous solution onto the surface of the support membrane, support The film may be immersed in an aqueous solution.

It is preferable that it is in the range of 5 second or more and 10 minutes or less, and, as for the contact time of a support membrane and polyfunctional amine aqueous solution, it is still more preferable if it exists in the range of 10 second or more and 3 minutes or less.

Then, it is preferable to remove the aqueous solution applied excessively by the liquid removal process. As a method of liquid removal, for example, there is a method in which the membrane surface is kept in the vertical direction to naturally fall. After the liquid is removed, the membrane surface may be dried to remove all or part of the water in the aqueous solution.

Then, the organic solvent solution containing the polyfunctional acid halide mentioned above is apply | coated to the support film coat | covered with the polyfunctional amine aqueous solution, and crosslinked polyamide is formed by interfacial polycondensation. 0.1 second or more and 3 minutes or less are preferable, and, as for time to perform interfacial polycondensation, it is more preferable if they are 0.1 second or more and 1 minute or less.

Although the density | concentration of the polyfunctional acid halide in an organic solvent solution is not specifically limited, If it is too low, formation of the polyamide which is an active layer may become inadequate and it may become a fault, and when too high, it will become disadvantageous in terms of cost. Therefore, about 0.01 weight% or more and 1.0 weight% or less are preferable.

Next, it is preferable to remove the organic solvent solution after reaction by a liquid removal process. For the removal of the organic solvent, for example, a method of grasping the membrane in the vertical direction to naturally remove excess organic solvent can be used.

In this case, as time to hold in a vertical direction, it is preferable that they are 1 minute or more and 5 minutes or less, and it is more preferable if they are 1 minute or more and 3 minutes or less. Since the holding time is 1 minute or more, it is easy to obtain a polyamide having a target function, and the occurrence of defects due to overdrying of the organic solvent can be suppressed by being 5 minutes or less.

Next, the polyamide obtained by the above-described method is washed with hot water for 1 minute or more and 60 minutes or less within the range of 25 ° C. or more and 90 ° C. or less to further improve the solute blocking performance and the permeate amount of the composite semipermeable membrane. Can be. However, if the temperature of the hot water is too high, the chemical resistance is lowered if it is rapidly cooled after the hot water washing treatment. Therefore, it is more preferable to perform hydrothermal washing within the range of 25 degreeC or more and 60 degrees C or less. In addition, when performing a hydrothermal washing process at the high temperature of 61 degreeC or more and 90 degrees C or less, it is preferable to cool slowly after a hydrothermal washing process. For example, there is a method of contacting with hot water of low temperature step by step and cooling to room temperature.

In the hot water washing step, an acid or an alcohol may be contained in the hot water. By containing an acid or an alcohol, formation of the hydrogen bond in polyamide becomes easier to control.

Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, and organic acids such as citric acid and oxalic acid. It is preferable to adjust so that acid concentration may become pH2 or less, and it is more preferable if it is pH1 or less.

Examples of the alcohol include monohydric alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, and polyhydric alcohols such as ethylene glycol and glycerin. The concentration of the alcohol is preferably 10% by weight or more and 100% by weight or less, and more preferably 10% by weight or more and 50% by weight or less.

In step (b), the hydrophilic polymer is introduced into the polyamide as a covalent bond. As described above, when introduced with a weak bond or interaction, the covalent bond is preferably an amide bond because it is easily detached by chemical cleaning or the like.

The structure, kind, and the like of the hydrophilic polymer introduced in the step (b) are as described above.

As this process, the method of contacting the polyamide surface with the aqueous solution containing a hydrophilic polymer and a condensing agent is used suitably. In order for the functional group on the surface of a polyamide and the functional group contained in a hydrophilic polymer to form an amide bond by condensation reaction, a hydrophilic polymer is introduce | transduced.

The method of bringing the separation functional layer into contact with an aqueous solution containing a hydrophilic polymer and a condensing agent is not particularly limited. For example, the entire composite semipermeable membrane may be immersed in an aqueous solution containing a hydrophilic polymer and a condensing agent, and a hydrophilic polymer and a condensing agent may be used. The aqueous solution may be sprayed onto the surface of the composite semipermeable membrane, and the method is not limited as long as the polyamide and the hydrophilic polymer and the condensing agent are in contact with each other.

The hydrophilic polymer to be brought into contact with the polyamide surface may be used alone or as a mixture of several species.

It is preferable to use a hydrophilic polymer as aqueous solution of 10 ppm or more and 1% or less by weight concentration. When the concentration of the hydrophilic polymer is 10 ppm or more, the functional group present in the polyamide and the hydrophilic polymer can be sufficiently reacted. On the other hand, when it exceeds 1%, since the hydrophilic polymer layer becomes thick, there is a fear that the amount of fresh water decreases.

Moreover, another compound can also be mixed with the aqueous solution of a hydrophilic polymer as needed. For example, in order to accelerate the reaction of the polyamide surface with the hydrophilic polymer, an alkali metal compound such as sodium carbonate, sodium hydroxide or sodium phosphate may be added. In addition, sodium dodecyl sulfate and benzene sulfonic acid are used to remove residual organic solvents, such as polyfunctional acid halides and polyfunctional amine compounds, oligomers generated by the reaction of these monomers, and the like, which remain in the polyamide. It is also preferable to add surfactant, such as sodium.

In this invention, a condensing agent refers to the compound which activates a carboxy group in water and advances the condensation reaction of the amino group of a polyamide. As such a compound, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, 1,3-bis (2,2-dimethyl-1,3-dioxolan-4-ylmethyl) carbodiimide and 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride (henceforth "DMT-MM") is mentioned. Among these compounds, DMT-MM is particularly preferably used in view of stability in the condensation reaction, low toxicity of the by-products after the condensation reaction, and the like.

The concentration of the condensing agent in the aqueous solution containing the hydrophilic polymer and the condensing agent is not particularly limited as long as it is higher than the concentration of the carboxyl group to be activated, and an effect sufficient for condensation with the reactive group can be obtained.

It is preferable that pH of the aqueous solution containing a hydrophilic polymer and a condensing agent is 2 or more and 12 or less. By carrying out pH of aqueous solution in the said range, deterioration of the film | membrane by an acid or an alkali can be suppressed and the salt removal performance of a composite semipermeable membrane can be maintained. When the hydrophilic polymer has a large number of functional groups having a negative charge, the contact frequency of the polyamide and the hydrophilic polymer decreases due to the negative charge generated by dissociation of the carboxyl group in the polyamide, more preferably pH6 or less, even more preferably pH5. It is as follows.

In addition, as a manufacturing method of a hydrophilic polymer, a well-known method is applicable. For example, a hydrophilic polymer can be synthesize | combined by mixing a monomer and a polymerization initiator in aqueous solution, and putting it under suitable temperature. Examples of the structure of the monomer are as described above. In addition, what is necessary is just to make ratio of a monomer the same as the ratio of the monomer unit made into the objective.

In the step (c), the amino group is converted into another functional group by contacting the amino group of the polyamide with a reagent for converting the functional group. Especially, it is preferable to convert a functional group by making it contact with the reagent which reacts with an amino group, and produces a diazonium salt or its derivative (s).

As a reagent which reacts with an amino group and produces a diazonium salt or its derivative (s), aqueous solution, such as a nitrous acid, its salt, and a nitrosyl compound, is mentioned. Since the aqueous solution of nitrous acid or nitrosyl compound has a property of generating and decomposing gas, it is preferable to sequentially generate nitrous acid by reaction between nitrite and acidic solution.

Generally, nitrite reacts with hydrogen ions to produce nitrous acid (HNO ₂ ), but the pH of the aqueous solution is efficiently produced at 7 or less, preferably 5 or less, more preferably 4 or less. Especially, the aqueous solution of sodium nitrite which reacted with hydrochloric acid or sulfuric acid in aqueous solution from the ease of handling is especially preferable.

The concentration of nitrous acid or nitrite in the reagent which reacts with an amino group to produce a diazonium salt or a derivative thereof is preferably in the range of 0.01% by weight or more and 1% by weight or less, and more preferably 0.05% by weight or more and 0.5% by weight or less. Range. If it is 0.01 weight% or more, sufficient effect will be acquired, and if concentration is 1 weight% or less, handling of a solution will be easy.

It is preferable that the temperature of a nitrous acid aqueous solution is 15 degreeC or more and 45 degrees C or less. If it is 15 degreeC or more, sufficient reaction time will be obtained, and if it is 45 degrees C or less, decomposition | disassembly of nitrous acid will not occur easily, and handling is easy.

The contact time with nitrous acid aqueous solution should just be the time which at least one of a diazonium salt and its derivative generate | occur | produces, and although it can process in a short time at high concentration, it is necessary for a long time if it is low concentration. Therefore, in the solution of the said concentration, it is preferable that it is within 10 minutes, and it is more preferable that it is within 3 minutes.

In addition, the method of making it contact is not specifically limited, Even if apply | coating the solution of this reagent, you may immerse the said composite semipermeable membrane in the solution of this reagent. The solvent which dissolves the reagent may be used as long as the reagent dissolves and the composite semipermeable membrane is not eroded. Moreover, as long as it does not interfere with reaction of an amino group and a reagent, a solution may contain surfactant, an acidic compound, an alkaline compound, etc.

Next, a part of the produced diazonium salt or its derivative is converted into another functional group. Some of the diazonium salts or derivatives thereof are converted to phenolic hydroxyl groups, for example by reaction with water. Furthermore, contact with a solution containing chloride ions, bromide ions, cyanide ions, iodide ions, boron fluoride, hypophosphorous acid, sodium bisulfite, sulfite ions, aromatic amines, hydrogen sulfide, thiocyanic acid, Converted to a functional group. In addition, the diazo coupling reaction occurs by contacting with the aromatic amine, thereby making it possible to introduce the aromatic group to the membrane surface. In addition, these reagents may be used singly, or may be used in combination, or may be contacted with another reagent a plurality of times.

As a reagent which a diazo coupling reaction generate | occur | produces, the compound which has an electron rich aromatic ring or a heteroaromatic ring is mentioned. As a compound which has an electron rich aromatic ring or a heteroaromatic ring, an unsubstituted heteroaromatic compound, the aromatic compound which has an electron donating substituent, and the heteroaromatic compound which has an electron donating substituent are mentioned.

Examples of the substituent for electron donating include an amino group, an ether group, a thioether group, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and the like. Specific examples of the compound include, for example, methoxyaniline bonded to the benzene ring in any positional relationship of aniline, ortho-position, meta-position, and para-position, and benzene in any positional relationship of ortho-position, meta-position, and para-position. Phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 3-aminobenzylamine, 4-aminobenzylamine, serpanyric acid bound to a ring , 3,3'-dihydroxybenzidine, 1-aminonaphthalene, 2-aminonaphthalene, or N-alkylate of these compounds.

3. Use of composite semipermeable membrane

The composite semipermeable membrane of the present invention has a cylindrical water collecting pipe circumference formed by drilling a plurality of holes together with raw water flow path materials such as plastic nets, permeate flow path materials such as tricoats, and films for increasing pressure resistance, if necessary. It is wound around and used suitably as a spiral composite semipermeable membrane element. Moreover, it can also be set as the composite semipermeable membrane module which this element connected in series or in parallel and accommodated in the pressure container.

In addition, the composite semipermeable membrane, its element, or module can be combined with a pump for supplying raw water to them, an apparatus for pretreating the raw water, or the like, to constitute a fluid separation device. By using this separation device, raw water can be separated into permeate such as beverage and concentrated water that has not permeated through the membrane, thereby obtaining water suitable for the purpose.

The higher the operating pressure of the fluid separation device is, the higher the salt removal rate is, but the energy required for operation is increased, and considering the durability of the composite semipermeable membrane, the operating pressure is 0.1 MPa when the treated water permeates through the composite semipermeable membrane. As mentioned above, 10 Mpa or less is preferable.

Although the salt removal rate decreases as the feed water temperature increases, the membrane permeation flow rate decreases as the temperature decreases, so 5 ° C or more and 45 ° C or less are preferable. In addition, when supply water pH becomes high, in the case of supply water of high salt concentrations, such as seawater, scales, such as magnesium, may generate | occur | produce, and operation | movement in a neutral area is preferable, since the film deterioration by high pH operation is feared. Do.

Examples of the raw water treated by the composite semipermeable membrane according to the present invention include a liquid mixture containing 500 mg / L to 100 g / L TDS (Total Dissolved Solids) such as seawater, brine, and waste water. In general, TDS refers to the total dissolved solids content and is expressed as "mass ÷ volume" or "weight ratio". By definition, the solution filtered with a 0.45 μm filter can be calculated from the weight of the residue evaporated at a temperature of 39.5 to 40.5 ° C., but more conveniently converted into practical salt (S).

Example

Although an Example is given to the following and this invention is demonstrated, this invention is not limited to these Examples at all. In addition, when simply described as 'ppm' means 'weight ppm'.

(NaCl removal rate)

The composite semipermeable membrane was supplied with the evaluation water adjusted to the temperature of 25 degreeC, pH7, and the sodium chloride concentration of 2,000 ppm at 1.55 Mpa, and membrane filtration process was performed. The electrical conductivity of the feed water and the permeate water was measured with an electric conductivity meter manufactured by Doa Denpa Kogyo Co., Ltd. to obtain respective practical salts, that is, NaCl concentrations. The NaCl removal rate was calculated based on the NaCl concentration thus obtained and the following formula.

NaCl removal rate (%) = 100 × {1- (NaCl concentration in permeate / NaCl concentration in feed water)}

(Permeate)

In the test of the preceding paragraph, the membrane permeation quantity of feed water (NaCl aqueous solution) was measured, and the value converted into the permeation amount (cubic meter) per day per square meter of membrane surface was made into the membrane permeation flow rate (m <3> / m <2> / day). .

In addition, the measurement of film | membrane performance was performed as follows.

Initially, the permeate amount when the aqueous solution of 25 degreeC, pH7, and NaCl concentration of 2,000 mg / L was filtered at 1.55 Mpa for 1 hour was measured, and it was called initial permeate amount (F1). Subsequently, polyoxyethylene (10) octylphenyl ether (POEOPE) was added to the aqueous solution so as to have a concentration of 100 mg / L, and the amount of permeated water when filtered for 1 hour was F2, and the value of F2 / F1 was calculated. Instead of POEOPE, the same measurement was performed using sodium dodecyl sulfate (SDS), and the value of F3 / F1 was calculated as the amount of permeated water when SDS was added and filtered for 1 hour.

(Airflow)

The air permeability was measured by a plastic tester based on JIS L1096 (2010). The substrate is cut into a size of 200 mm x 200 mm, mounted on a plastic tester, and the suction pan and the air hole are adjusted so that the inclined barometer has a pressure of 125 kPa, the pressure indicated by the vertical barometer at this time and the used air hole. Aeration was obtained from the type of. The plastic tester used KES-F8-AP1 made by Kato Tech Corporation.

Synthesis of Hydrophilic Polymer

Synthesis Example 1

After dissolving [(2-methacryloyloxy) ethyl] dimethyl (3-sulfopropyl) -ammonium hydroxide (MEDMSPAH) in pure water previously bubbled with nitrogen, sodium persulfate as an initiator was added, and 70 The polymerization reaction was performed at 2 ° C. for a polymer solution.

Synthesis Example 2

MEDMSPAH and acrylic acid (AA) were added in a molar ratio of 1: 1, dissolved and mixed in pure water bubbled with nitrogen, and then mixed with sodium persulfate as an initiator, followed by a polymerization reaction at 70 ° C for 2 hours to give a polymer solution. Got it.

Synthesis Example 3

The reaction was carried out in the same manner as in Synthesis Example 2, except that (2-methacryloyloxy) ethyl [(2-trimethylammonio) ethyl] phosphate (METMAEP) was used instead of MEDMSPAH, and a polymer solution was obtained.

Synthesis Example 4

The reaction was carried out in the same manner as in Synthesis Example 2, except that 3-{[2- (methacryloyloxy) ethyl] dimethylammonio} propionate (MEDMAP) was used instead of MEDMSPAH, and a polymer solution was obtained.

Synthesis Example 5

Except having changed the molar ratio of MEDMSPAH and AA to 8: 1, it carried out similarly to the synthesis example 2, and obtained the polymer solution.

Synthesis Example 6

The reaction was carried out in the same manner as in Synthesis example 2 except that the molar ratio of MEDMSPAH and AA was changed to 4: 1 to obtain a polymer solution.

Synthesis Example 7

The reaction was carried out in the same manner as in Synthesis example 2 except that the molar ratio of MEDMSPAH and AA was changed to 1: 4 to obtain a polymer solution.

Synthesis Example 8

The reaction was carried out in the same manner as in Synthesis example 2 except that the molar ratio of MEDMSPAH to AA was changed to 1: 8 to obtain a polymer solution.

Synthesis Example 9

The reaction was carried out in the same manner as in Synthesis example 2, except that methacrylic acid (MAA) was used instead of AA to obtain a polymer solution.

Synthesis Example 10

The reaction was carried out in the same manner as in Synthesis example 2, except that maleic acid (MA) was used instead of AA and the molar ratio was changed to 1: 4 to obtain a polymer solution.

Synthesis Example 11

The reaction was performed in the same manner as in Synthesis Example 2 except that 2-aminoethyl methacrylate (AEMA) was used instead of AA to obtain a polymer solution.

Synthesis Example 12

MAA and AEMA were added at a molar ratio of 1: 1, dissolved and mixed in pure water bubbled with nitrogen, and then mixed with sodium persulfate as an initiator, followed by polymerization at 70 ° C for 2 hours to obtain a polymer solution.

Synthesis Example 13

The reaction was performed in the same manner as in Synthesis Example 12 except that the molar ratio of MAA and AEMA was 2: 1 to obtain a polymer solution.

Synthesis Example 14

The reaction was carried out in the same manner as in Synthesis Example 12 except that the molar ratio of MAA and AEMA was changed to 1: 2 to obtain a polymer solution.

(Molecular weight measurement method)

The aqueous solution obtained in each synthesis example was diluted with 20mM phosphate buffer (pH7.4) to 1.0w / v%, and this solution was filtered through a membrane filter of 0.45 mu m to obtain a test solution, and subjected to GPC (gel permeation chromatography). The weight average molecular weight was measured and calculated by this. The molar ratio and weight average molecular weight of the copolymer obtained by each synthesis example are shown in Table 1. In addition, the measurement conditions of GPC analysis are as follows.

(Measurement conditions of GPC analysis)

column; TSKgel PWXL-CP (made by Tosoh Corporation),

Eluting solvent; 20 mM phosphate buffer (pH7.4),

Standard material; Polyethylene glycol (manufactured by Polymer Laboratories Ltd.),

detection; Differential refractometer RI-8020 (product made from Tosoh Corporation),

Flow rate; 0.5 mL / min,

Sample solution usage; 10 μL, column temperature; 45 ° C.

(Production of composite semipermeable membrane)

(Comparative Example 1)

A porous support layer by casting a 15.0% by weight DMF solution of polysulfone (PSf) on a polyester nonwoven fabric (ventilation of 2.0 mL / cm 2 / sec) containing long fibers under 25 ° C. conditions, immediately immersed in pure water and left for 5 minutes. The support film whose thickness is 40 micrometers was produced.

Next, the supporting membrane was immersed in 3.5% by weight of m-PDA aqueous solution, and then an excess of aqueous solution was removed, and an n-decane solution dissolved in 0.14% by weight of TMC was applied so that the surface of the porous support layer was completely wet. . Next, in order to remove excess solution from a film | membrane, liquid was removed by making a film | membrane perpendicular | vertical, and it sprayed 25 degreeC air using a blower, and dried, and wash | cleaned with 40 degreeC pure water. The film performance and the film performance after fouling at the time of film forming of the composite semipermeable membrane obtained in this way were measured, and were the values shown in Table 2.

(Comparative Example 2)

The composite semipermeable membrane obtained by the comparative example 1 was immersed in 0.3 weight% sodium nitrite aqueous solution adjusted to pH3 and 35 degreeC for 1 minute. In addition, the pH of sodium nitrite was adjusted with sulfuric acid. Next, the composite semipermeable membrane of Comparative Example 2 was obtained by immersing in 0.1 wt% aqueous sodium sulfite solution at 35 ° C. for 2 minutes. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Comparative Example 3)

The composite semipermeable membrane obtained in Comparative Example 1 was contacted with a solution obtained by adjusting the polymer obtained in Synthesis Example 1 to 400 ppm and DMT-MM to 0.1%, and then washed with water at 20 ° C for 24 hours. Next, it was immersed for 1 minute in 0.3 weight% sodium nitrite aqueous solution adjusted to pH3 and 35 degreeC. In addition, the pH of sodium nitrite was adjusted with sulfuric acid. Furthermore, the composite semipermeable membrane of the comparative example 3 was obtained by immersing in 0.1 weight% sodium sulfite aqueous solution at 35 degreeC for 2 minutes. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Comparative Example 4)

The composite semipermeable membrane obtained in Comparative Example 1 was contacted with a solution obtained by adjusting the polymer obtained in Synthesis Example 2 to 400 ppm for 24 hours at 20 ° C, and then washed with water. It was immersed for 1 minute in 0.3 weight% sodium nitrite aqueous solution adjusted to pH3 and 35 degreeC. In addition, the pH of sodium nitrite was adjusted with sulfuric acid. Next, the composite semipermeable membrane of Comparative Example 4 was obtained by immersing in 0.1 wt% aqueous sodium sulfite solution at 35 ° C. for 2 minutes. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Comparative Example 5)

The composite semipermeable membrane obtained in Comparative Example 1 was washed with water after being brought into contact with 20 ° C for 24 hours in a solution obtained by adjusting the polymer obtained in Synthesis Example 12 to 300 ppm and DMT-MM to 0.1%. Next, it was immersed for 1 minute in 0.3 weight% sodium nitrite aqueous solution adjusted to pH3 and 35 degreeC. In addition, the pH of sodium nitrite was adjusted with sulfuric acid. Furthermore, the composite semipermeable membrane of the comparative example 5 was obtained by immersing in 0.1 weight% of sodium sulfite aqueous solution at 35 degreeC for 2 minutes. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Comparative Example 6)

Using the polymer obtained in Synthesis Example 11, the treatment was carried out in the same manner as in Comparative Example 5 except that the polymer concentration was 500 ppm, to obtain a composite semipermeable membrane of Comparative Example 6. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Comparative Example 7)

Using the polymer obtained in Synthesis Example 14, the treatment was carried out in the same manner as in Comparative Example 5 except that the polymer concentration was 500 ppm, to obtain a composite semipermeable membrane of Comparative Example 7. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 1)

The composite semipermeable membrane obtained in Comparative Example 1 was washed with water after adjusting the polymer obtained in Synthesis Example 2 to 400 ppm and DMT-MM in a solution adjusted to 0.1% for 24 hours at 20 ° C. Next, it was immersed for 1 minute in 0.3 weight% sodium nitrite aqueous solution adjusted to pH3 and 35 degreeC. In addition, the pH of sodium nitrite was adjusted with sulfuric acid. Furthermore, the composite semipermeable membrane of Example 1 was obtained by immersing in 0.1 weight% of sodium sulfite aqueous solution at 35 degreeC for 2 minutes. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 2)

Except having used the polymer obtained by the synthesis example 3, it carried out similarly to Example 1, and obtained the composite semipermeable membrane of Example 2. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 3)

Except having used the polymer obtained by the synthesis example 4, it processed like Example 1 and obtained the composite semipermeable membrane of Example 3. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 4)

Using the polymer obtained in Synthesis Example 5, the treatment was performed in the same manner as in Example 1 except that the polymer concentration was 2000 ppm, to obtain a composite semipermeable membrane of Example 4. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 5)

Using the polymer obtained in Synthesis Example 6, the treatment was carried out in the same manner as in Example 1 except that the polymer concentration was set to 1000 ppm, to obtain a composite semipermeable membrane of Example 5. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 6)

Using the polymer obtained in Synthesis Example 7, the treatment was carried out in the same manner as in Example 1 except that the polymer concentration was 300 ppm, to obtain a composite semipermeable membrane of Example 6. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 7)

Using the polymer obtained in Synthesis Example 8, the treatment was carried out in the same manner as in Example 1 except that the polymer concentration was set to 150 ppm, to obtain a composite semipermeable membrane of Example 7. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 8)

Except having used the polymer obtained by the synthesis example 9, it processed like Example 1 and obtained the composite semipermeable membrane of Example 8. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 9)

Using the polymer obtained in Synthesis Example 10, the treatment was carried out in the same manner as in Example 1 except that the polymer concentration was set to 1000 ppm, to obtain a composite semipermeable membrane of Example 9. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Example 10)

Using the polymer obtained in Synthesis Example 13, the treatment was carried out in the same manner as in Example 1 except that the polymer concentration was 250 ppm, to obtain a composite semipermeable membrane of Example 10. When the obtained composite semipermeable membrane was evaluated, membrane performance was the value shown in Table 2.

(Bubble contact angle measurement)

The bubble contact angle adhered to the separation membrane functional layer by immersing the composite semipermeable membrane at 25 ° C. for 16 hours in an aqueous solution adjusted to the pH to be measured and using a contact angle measuring device (DM-301, manufactured by Kyowa Chemical Co., Ltd.). Was measured. The measurement was made into N = 3 times by making it the thing of the bubble of 0.5-2.0 microliters. At this time, the bubble was supplied using a syringe guide. The bubble contact angle of the composite semipermeable membrane produced by each comparative example and the Example was the value shown in Table 2.

As described above, it can be seen that the composite semipermeable membrane of the present invention can realize excellent fouling resistance over a long period of time. That is, it has a high adhesion inhibitory ability to a membrane contaminant, and can maintain a high performance stably for a long time.

Although this invention was detailed also demonstrated with reference to the specific embodiment, it is clear for those skilled in the art that various changes and correction can be added without deviating from the mind and range of this invention. This application is based on the JP Patent application 2016-251200 of an application on December 26, 2016, The content is taken in here as a reference.

When the composite semipermeable membrane of the present invention is used, raw water can be separated into permeated water such as beverage and concentrated water that has not permeated the membrane, thereby obtaining water suitable for the purpose. In particular, the composite semipermeable membrane of the present invention can be suitably used for desalination of brine or seawater.

Claims (12)

A composite semipermeable membrane having a support membrane including a substrate and a porous support layer, and a separation functional layer provided on the porous support layer,
The composite semipermeable membrane, wherein the separation functional layer contains a crosslinked polyamide and a hydrophilic polymer, and satisfies the following conditions (A) and (B).
(A) The said hydrophilic polymer contains the functional group which has a positive charge, and the functional group which has a negative charge, and the said hydrophilic polymer is negatively charged.
(B) The said hydrophilic polymer is covalently bonded to the said crosslinked polyamide. The said hydrophilic polymer WHEREIN: The ratio (N1 / N2) of the number N1 of the functional group which has the said positive charge, and the number N2 of the functional group which has the said negative charge is 15/85 or more and 45/55 or less Composite semipermeable membrane. The composite semipermeable membrane according to claim 1 or 2, wherein the hydrophilic polymer has a weight average molecular weight of 2,000 or more and 1,500,000 or less. The composite semipermeable membrane according to any one of claims 1 to 3, wherein the charged density of the hydrophilic polymer is 7.5 mmol / g or more and 10.5 mmol / g or less. The composite semipermeable membrane according to any one of claims 1 to 4, wherein the negative charge density of the hydrophilic polymer is 4.5 mmol / g or more and 8.0 mmol / g or less. The separation contact layer according to any one of claims 1 to 5, wherein the bubble contact angle in the aqueous solution at pH 3 is θ _A , and the bubble contact angle in the aqueous solution at pH 11 is θ _{B. A} composite semipermeable membrane satisfying <θ _A , θ _B <180 ° and (θ _B -θ _A )> 5 °. The monomer Q according to any one of claims 1 to 6, wherein the hydrophilic polymer contains a functional group having a charged charge, and the charged monomer contains a monomer P having a negative charge, a functional group having a positive charge, and a functional group having a negative charge. Composite semipermeable membrane which is a copolymer of. The ratio (PN: QN) of the number (PN) of the monomer units derived from the monomer P and the number (QN) of the monomer units derived from the monomer Q included in the copolymer is 80:20 to 20. A composite semipermeable membrane of: 80. The composite semipermeable membrane according to claim 7 or 8, wherein the monomer P is at least one compound selected from the group consisting of acrylic acid, methacrylic acid and maleic acid. The composite semipermeable membrane according to any one of claims 7 to 9, wherein the monomer Q is at least one compound represented by the following formula (1) or formula (2).

(In the formulas (1) and (2), R ¹ is H or CH ₃ , and R ² , R ³ , R ^6, and R ⁷ are each independently an alkylene group having 1 to 5 carbon atoms, or 1 carbon atom. Is an oxyalkylene group of 5 to 5, R ⁴ , R ⁵ , R ⁸ , R ⁹ and R ¹⁰ are each independently an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, and X is O, NH and or S, Y is SO ₃ ^-, OSO ₃ ^-, or CO ₂ ^- a). The composite semipermeable membrane according to any one of claims 1 to 10, wherein the covalent bond is an amide bond. (a) forming a crosslinked polyamide on a support membrane comprising a substrate and a porous support layer, and
(b) A step of covalently bonding a hydrophilic polymer having a negatively charged functional group and a negatively charged functional group to the crosslinked polyamide obtained in (a) above.
Method for producing a composite semipermeable membrane having a.