WO2014084356A1 - Separation membrane comprising fluorine-containing copolymer - Google Patents

Separation membrane comprising fluorine-containing copolymer Download PDF

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Publication number
WO2014084356A1
WO2014084356A1 PCT/JP2013/082184 JP2013082184W WO2014084356A1 WO 2014084356 A1 WO2014084356 A1 WO 2014084356A1 JP 2013082184 W JP2013082184 W JP 2013082184W WO 2014084356 A1 WO2014084356 A1 WO 2014084356A1
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copolymer
separation membrane
water
organic solvent
formula
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PCT/JP2013/082184
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French (fr)
Japanese (ja)
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弘賢 山本
山本　達也
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旭硝子株式会社
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Priority to JP2014549921A priority Critical patent/JPWO2014084356A1/en
Publication of WO2014084356A1 publication Critical patent/WO2014084356A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F216/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical
    • C08F216/12—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical by an ether radical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/38—Polyalkenylalcohols; Polyalkenylesters; Polyalkenylethers; Polyalkenylaldehydes; Polyalkenylketones; Polyalkenylacetals; Polyalkenylketals
    • B01D71/381—Polyvinylalcohol
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/76—Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
    • C08F214/18—Monomers containing fluorine
    • C08F214/26—Tetrafluoroethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F216/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical
    • C08F216/12—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical by an ether radical
    • C08F216/14—Monomers containing only one unsaturated aliphatic radical
    • C08F216/16—Monomers containing no hetero atoms other than the ether oxygen
    • C08F216/18—Acyclic compounds
    • C08F216/20—Monomers containing three or more carbon atoms in the unsaturated aliphatic radical
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F218/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
    • C08F218/02—Esters of monocarboxylic acids
    • C08F218/04—Vinyl esters
    • C08F218/08—Vinyl acetate
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D127/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers
    • C09D127/02—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment
    • C09D127/12—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Coating compositions based on derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C09D127/18—Homopolymers or copolymers of tetrafluoroethene
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D129/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Coating compositions based on hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Coating compositions based on derivatives of such polymers
    • C09D129/02—Homopolymers or copolymers of unsaturated alcohols
    • C09D129/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D129/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Coating compositions based on hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Coating compositions based on derivatives of such polymers
    • C09D129/10—Homopolymers or copolymers of unsaturated ethers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D133/04—Homopolymers or copolymers of esters
    • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09D133/08—Homopolymers or copolymers of acrylic acid esters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/30—Polyalkenyl halides
    • B01D71/32—Polyalkenyl halides containing fluorine atoms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/38—Polyalkenylalcohols; Polyalkenylesters; Polyalkenylethers; Polyalkenylaldehydes; Polyalkenylketones; Polyalkenylacetals; Polyalkenylketals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/40—Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/58—Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
    • B01D71/60—Polyamines
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/08—Seawater, e.g. for desalination
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination
    • Y02A20/131—Reverse-osmosis

Definitions

  • the present invention relates to a separation membrane made of a fluorine-containing copolymer.
  • separation membranes have been widely used for river and lake water purification applications, sewage and wastewater treatment applications, seawater desalination applications, food production applications, and the like. These separation membranes are generally used after being regularly cleaned because insoluble substances accumulate during use and cause clogging of the membrane. For biofouling that is particularly difficult to clean, an oxidizing agent such as sodium hypochlorite is used.
  • Non-Patent Document 1 Since polyamide is oxidatively decomposed (Non-Patent Document 1), durability against the above-mentioned sodium hypochlorite is insufficient, and various studies have been made. For example, a method has been proposed in which the polyamide film surface is coated with another polymer to control the zeta potential of the film surface to about 0 mV, prevent adhesion of charged contaminants, and suppress fouling (patent) References 1, 2).
  • polyvinylidene fluoride is being studied as a material that is durable to oxidizing agents.
  • a porous film that improves hydrophilicity by blending a hydrophilic polymer with polyvinylidene fluoride and suppresses fouling Patent Document 3
  • a hydrophilizing agent that generates a hydrophilic compound by a decomposition reaction of polyvinylidene fluoride A porous membrane containing a decomposition product of (Patent Document 4) has been proposed.
  • a separation membrane using a polymer obtained by saponifying at least a part of an acetate group contained in a copolymer of tetrafluoroethylene and vinyl acetate has also been proposed.
  • JP 2006-239636 A Japanese Patent No. 3379963 Japanese Patent No. 4600172 JP 2005-296846 A JP-A-5-261256
  • Patent Documents 1 and 2 are complicated in operation, and a special technique is required to completely cover the film surface with the coating film.
  • the hydrophilic polymer may bleed out from the membrane, and the hydrophilicity of the membrane may decrease.
  • the generated hydrophilic compound may bleed out from the membrane.
  • NF membranes nanofiltration membranes
  • RO membranes reverse osmosis membranes
  • the substance to be separated is a biological material or the like, and is not suitable for a nanofiltration membrane (NF membrane) or a reverse osmosis membrane (RO membrane).
  • the object of the present invention is to provide a separation membrane that is excellent in fouling resistance, hydrophilicity, and oxidant resistance, and also excellent in desalting performance required for seawater desalination.
  • the present invention provides a separation membrane having the following constitutions [1] to [15], a method for producing the separation membrane, and a composition for producing the separation membrane.
  • a copolymer comprising a unit represented by the following formula (1) and a unit represented by the following formula (2) and having a mass average molecular weight of 50,000 to 1,000,000, A separation membrane having a salt rejection of at least 3% in a crossflow method at 25 ° C. and 0.45 MPaG using a 15 mass% sodium chloride aqueous solution.
  • X and Y are each independently H, F, CF 3 or Cl.
  • Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 .
  • R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure.
  • R 1 to R 4 are each independently H or a monovalent organic group. However, the proportion of units in which R 1 to R 4 are H among the units represented by the formula (2) contained in the copolymer is 50 mol% or more.
  • R is a single bond, O (CH 2 ) n or (OCH 2 CH 2 ) m (where n is an integer of 2 to 4, and m is an integer of 1 to 4) Or a separation membrane according to any one of [1] to [5].
  • R is a single bond, O (CH 2 ) n or (OCH 2 CH 2 ) m (where n is an integer of 2 to 4, and m is an integer of 1 to 4) Or a separation membrane according to any one of [1] to [5].
  • a method for producing the separation membrane according to any one of [1] to [6] A film of the liquid composition is formed from a liquid composition in which the copolymer is dissolved or dispersed in a water-miscible organic solvent, and a part of the organic solvent is removed from the surface of the liquid composition film.
  • a method for producing a separation membrane wherein a membrane of the liquid composition is converted into a solid membrane by forming a partially dried membrane and then substituting the remaining organic solvent with water.
  • the water-miscible organic solvent is at least one organic solvent selected from the group consisting of alcohols, amides, esters and carbonates.
  • Step (3) A part of the organic solvent is removed from the surface of the liquid composition film on the substrate surface, and the amount of the organic solvent (100% by mass) in the liquid composition film before removing the organic solvent. Forming a partially dried film containing 30 to 80% by mass of an organic solvent.
  • Step (4) A step of bringing the substrate having the partially dried film into contact with water, replacing the organic solvent with water, and forming a solid film containing water.
  • Step (5) A step of heating the solid film containing water to a temperature of 30 to 100 ° C.
  • a copolymer containing a unit represented by the following formula (1) and a unit represented by the following formula (2) and having a mass average molecular weight of 50,000 to 1,000,000 is mixed with water:
  • a liquid composition for producing a separation membrane which is a liquid composition dissolved or dispersed in a functional organic solvent.
  • X and Y are each independently H, F, CF 3 or Cl.
  • Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 .
  • R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure.
  • R 1 to R 4 are each independently H or a monovalent organic group.
  • the proportion of units in which R 1 to R 4 are H among the units represented by the formula (2) contained in the copolymer is 50 mol% or more.
  • the separation membrane of the present invention has excellent fouling resistance, hydrophilicity and oxidant resistance, and also has excellent desalting performance required for seawater desalination.
  • the separation membrane of the present invention has a salt rejection of at least 3% in a cross flow method at 25 ° C. and 0.45 MPaG (absolute pressure) using a 0.15 mass% sodium chloride aqueous solution.
  • the salt rejection is obtained by the following equation. [(0.15-sodium chloride concentration in the filtrate (% by mass)) / 0.15] ⁇ 100 (%)
  • the sodium sodium chloride concentration in the filtrate can be determined from, for example, the electrical conductivity. It is shown in the examples.
  • the salt rejection is 3% or more, it can be suitably used for applications such as seawater desalination, brine desalination, and food production.
  • the preferable range of the salt rejection depends on the purpose of use, it is particularly preferably 5% or more.
  • the separation membrane preferably has a filtration flux at 25 ° C. and 0.45 MPaG of 10 L / m 2 ⁇ day or more. If the filtration flux is in the above range, it can be suitably used for applications such as seawater desalination, brine demineralization, and food production. Filtration flux is more preferably at least 50L / m 2 ⁇ h, more 100L / m 2 ⁇ h are particularly preferred.
  • the zeta potential at 25 ° C. on the surface of the separation membrane is preferably ⁇ 10 mV to +10 mV, and particularly preferably ⁇ 5 mV to +5 mV, from the viewpoint that adhesion of charged substances can be suppressed and clogging can be prevented (fouling resistance).
  • the zeta potential is in the above range, it is suitable for uses such as seawater desalination, brine demineralization, and food production.
  • the thickness of the separation membrane can be appropriately selected depending on the application, but is preferably 0.1 ⁇ m to 1 mm, more preferably 1 to 500 ⁇ m, and particularly preferably 1 to 100 ⁇ m in a dry state (state not containing water).
  • the separation membrane of the present invention comprises a unit represented by the formula (1) and a unit represented by the formula (2) as described later, and has a mass average molecular weight of 50,000 to 1,000,000.
  • a polymer hereinafter also referred to as “copolymer (A)”.
  • the separation membrane is excellent in hydrophilicity and durability to an oxidizing agent.
  • the separation membrane of the present invention may be manufactured by combining other materials together with the copolymer (A) from the viewpoint that the strength can be improved and the thickness of the separation membrane can be reduced.
  • the other materials include organic materials such as polyethylene, polypropylene, polysulfone, polyethersulfone, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, cellulose acetate, and polyamide, and inorganic materials such as ceramic.
  • a separation membrane is formed by weaving a hollow fiber of the copolymer (A) and a hollow fiber of another material, and a separation membrane is formed from a mixture of the copolymer (A) and another material. And a method of forming on a separation membrane made of other materials.
  • the thickness of the separation membrane obtained by compositing other materials with the copolymer (A) is preferably 0.01 to 100 ⁇ m, particularly 0.05 to 50 ⁇ m in a dry state (containing no water). preferable.
  • the fluorine-containing copolymer (copolymer (A)) in the present invention is represented by the unit represented by the following formula (1) (hereinafter also referred to as “unit (1)”) and the following formula (2). And a unit (hereinafter also referred to as “unit (2)”).
  • X and Y are each independently H, F, CF 3 or Cl.
  • Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 .
  • R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure.
  • R 1 to R 4 are each independently H or a monovalent organic group. However, of the units (2) contained in the copolymer, the proportion of units in which R 1 to R 4 are H is 50 mol% or more.
  • Unit (1) is a unit having hydrophobicity.
  • X is preferably F because the hydrophobicity of the unit (1) is increased.
  • One type or two or more types of X present in the copolymer (A) may be used, but one type is preferable in terms of stable production.
  • Y is preferably F from the viewpoint of excellent hydrophobicity of the unit (1).
  • Cl is preferable from the point that a copolymer (A) is excellent in heat resistance.
  • Y present in the copolymer (A) may be one type or two or more types, but one type is preferable in terms of stable production.
  • the unit (1) is preferably a unit in which X is F and Y is F or Cl from the viewpoint of easy availability of the monomer.
  • the proportion of units in which R 1 to R 4 are H is 70 to 100 mol% in that the copolymer (A) is excellent in hydrophilicity. Is preferred, with 85 to 100 mol% being particularly preferred.
  • Z is preferably OR 1 and particularly preferably OH.
  • One type or two or more types of Z present in the copolymer (A) may be used, but one type is preferable in terms of stable production.
  • the monovalent organic group in R 1 to R 4 is a primary or secondary alkyl group having 1 to 6 carbon atoms which may contain an etheric oxygen atom, or one or more hydrogen atoms of the alkyl group Is preferably a group substituted with a substituent.
  • the alkyl group may be linear or branched.
  • functional groups such as a hydroxyl group, an amino group, and a glycidyl group, a fluorine atom, etc. are mentioned.
  • the monovalent organic group in R 1 to R 4 is —CR 5 R 6 R 7 (R 5 , R 6 and R 7 are each independently an alkyl group having 1 to 3 carbon atoms), and 1 carbon atom.
  • R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure.
  • the divalent linking group which may contain an etheric oxygen atom is preferably an alkylene group having 1 to 100 carbon atoms or an alkylene group containing 1 to 100 carbon atoms containing an etheric oxygen atom, and has 1 to 50 carbon atoms. More preferably an alkylene group having 1 to 50 carbon atoms containing an etheric oxygen atom, particularly an alkylene group having 1 to 10 carbon atoms or an alkylene group having 1 to 10 carbon atoms containing an etheric oxygen atom. preferable.
  • the divalent linking group that may contain a ring structure is preferably a cyclohexylene group or a cyclohexylene group containing an etheric oxygen atom.
  • R is a single bond, O (CH 2 ) n or (OCH 2 CH 2 ) m in the point that the copolymer (A) is excellent in hydrophilicity, where n is an integer of 2 to 4, and m is It is preferably an integer of 1 to 4.
  • the plurality of Rs present in the copolymer (A) may be one type or two or more types, but one type is preferable in that it can be stably produced.
  • the copolymer (A) has a unit in which X is F and Y is F or Cl as a unit (1), Z is OR 1 , R is a single bond, O (CH 2 ) Those having units of n or (OCH 2 CH 2 ) m (where n is an integer of 2 to 4 and m is an integer of 1 to 4) are preferred.
  • R 1 the above-mentioned —CR 5 R 6 R 7 or an acyl group having 2 to 6 carbon atoms is preferable, and —CR 5 R 6 R 7 is particularly preferable.
  • the mass average molecular weight (Mw) of the copolymer (A) is from 50,000 to 1,000,000, preferably from 100,000 to 800,000, particularly preferably from 100,000 to 500,000. If the mass average molecular weight is not less than the lower limit of the above range, a separation membrane excellent in strength can be obtained, and if it is not more than the upper limit, a homogeneous separation membrane can be formed.
  • the mass average molecular weight (Mw) can be measured by GPC using a polystyrene standard.
  • the molecular weight distribution (Mw / Mn) of the copolymer (A) is preferably from 1 to 5, particularly preferably from 1 to 3. When the amount is not more than the upper limit of the above range, a gel material is less and a separation membrane having excellent strength can be formed.
  • the copolymer (A) is preferably composed only of the unit (1) and the unit (2), but in addition to the unit (1) and the unit (2) as long as the effects of the present invention are not impaired,
  • the unit (3) may be included.
  • the unit (3) include units based on vinyl esters other than the unit (2), units based on vinyl ethers to which alkyl groups other than the unit (2) are bonded, units based on vinyl fluoride or alkenes, and the like. From the viewpoint of increasing the toughness of the copolymer (A), a unit based on an alkyl group-bonded vinyl ether and a unit based on vinyl fluoride or an alkene are preferable from the viewpoint of increasing the strength of the separation membrane.
  • the unit (3) is preferably a unit having no ionic functional group in that the zeta potential of the copolymer (A) at 25 ° C. can be about ⁇ 10 mV to +10 mV.
  • R 9 is an optionally substituted group selected from the group consisting of a primary or secondary alkyl group having 1 to 6 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms. Examples thereof include a methyl group, an ethyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a cyclohexyl group, a hydroxyethyl group, a hydroxybutyl group, and a heptafluoropentyl group.
  • the substituent include a hydroxyl group amino group, a glycidyl group, and a fluorine atom.
  • Preferred units as units based on alkenes are units based on ethylene, propylene or isobutene.
  • the molar ratio of each unit contained in the copolymer is preferably 25/75 to 75/25, preferably 40/60 to 60/40. Is more preferable, 45/55 to 55/45 is more preferable, and 50/50 is particularly preferable.
  • the molar ratio of unit (1) / [unit (2) + unit (3)] is preferably 40/60 to 60/40, and 45/55 to 55/45 is More preferably, 50/50 is particularly preferable.
  • the molar ratio of unit (2) / unit (3) is preferably 45/5 to 25/25, particularly preferably 40/10 to 25/25.
  • the alternating arrangement ratio of the unit (1) and the unit (2) is preferably 80% or more, more preferably 95% or more, and 97 % Or more is particularly preferable.
  • the alternating arrangement ratio of the unit (1) and the unit (2) or (3) is preferably 80% or more, and the alternating arrangement ratio is 95% or more is more preferable, and 97% or more is particularly preferable.
  • the alternating arrangement ratio of the copolymer (A) is in the above range, the strength and elongation of the separation membrane are excellent. Further, since the unit (2) exists uniformly, the hydrophilicity of the separation membrane is excellent.
  • the alternating arrangement ratio of the copolymer is the ratio of the number of combinations in which units based on different monomers are adjacent to the total number of combinations of two adjacent units.
  • the copolymer is represented by 1, 2, 1, 2, 2, 1, 2, 1, 2, 1, 2 (where 1 represents unit (1) and 2 represents unit (2) ),
  • the number of combinations of two adjacent units is 10, and the number of combinations in which units based on different monomers are adjacent is 9, so that the alternating arrangement ratio is 90%.
  • the alternating sequence ratio is determined from the polymerization reactivity ratio of plural types of monomers used for the synthesis of the copolymer. When the polymerization reactivity of each monomer is low and close, the alternating sequence ratio is improved.
  • the manufacturing method of a copolymer (A) can be selected from a well-known method using the monomer for forming unit (1) and (2). Examples of the method include the following methods (i) and (ii).
  • (I) A method of copolymerizing a monomer that forms unit (1) upon polymerization and a monomer that forms unit (2).
  • (Ii) obtained by copolymerizing a monomer that forms the unit (1) by polymerization and a monomer that forms the unit (2) by a chemical reaction (such as deprotection reaction).
  • the method (i) or (ii) is preferably used when Z is OH, (i) or (ii) is used when NH 2 is used, (ii) is used when COOH is used, and the method (ii) is used when SO 3 H is used. It is done.
  • the method includes the following polymerization step and deprotection step.
  • Polymerization step a fluorine-containing olefin represented by the following formula (4) (hereinafter, also referred to as “monomer (4)”) and a vinyl monomer represented by the following formula (5) (hereinafter, “ A step of copolymerizing with the monomer (5) ”.
  • Deprotection step a step of substituting R 10 of the polymerization unit based on the monomer (5) in the copolymer obtained in the polymerization step with a hydrogen atom to generate a hydroxyl group.
  • CF 2 CXY (4)
  • CH 2 CHOR 10 (5)
  • X and Y are each independently H, F, CF 3 or Cl.
  • R 10 is a protecting group substituted by a hydrogen atom by a deprotection reaction. .
  • a fluorine-containing olefin / vinyl monomer copolymer (hereinafter referred to as “copolymer”) having a unit based on the monomer (4) and a unit based on the monomer (5) in the polymerization step. B) ”)), and then the unit based on the fluorinated olefin is obtained by substituting R 10 of the unit based on the monomer (5) in the copolymer (B) with a hydrogen atom by a deprotection reaction.
  • a copolymer (A) having units based on vinyl alcohol.
  • the monomer (4) include tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and the like. Of these, tetrafluoroethylene or chlorotrifluoroethylene is preferred, and tetrafluoroethylene is particularly preferred from the viewpoint of excellent heat resistance.
  • a monomer (4) may be used individually by 1 type, and may use 2 or more types together.
  • R 10 in the monomer (5) is a protecting group that protects a hydroxyl group as an ether or an ester, and is a group that is substituted with a hydrogen atom by a deprotection reaction performed in the next deprotection step.
  • R 10 is substituted with a hydrogen atom by a deprotection reaction, a hydroxyl group is formed.
  • R 10 a protecting group usually used in the field of organic chemistry can be used.
  • —CR 5 R 6 R 7 an alkoxymethyl group having 1 to 6 carbon atoms, a tetrahydrofuryl group, a tetrahydropyranyl group
  • an acyl group having 2 to 6 carbon atoms or —Si (R 8 ) 3 is preferable, —CR 5 R 6 R 7 and an acyl group having 2 to 6 carbon atoms are more preferable, and —CR 5 R 6 R 7 is particularly preferable.
  • R 5 , R 6 , R 7 and R 8 are as already described for the unit (2).
  • Examples of the monomer (5) include t-butyl vinyl ether, 1,1-dimethylpropyl vinyl ether, methoxymethyl vinyl ether, tetrahydrofuryl vinyl ether, tetrahydropyranyl vinyl ether, vinyl ether such as vinyloxytrimethylsilane or vinyloxydimethylphenylsilane, acetic acid Carboxylic acid vinyl esters such as vinyl are preferred.
  • Vinyl ether is more preferable from the viewpoint that the alternating copolymerization ratio of the obtained copolymer (A) can be 95% or more, and t-butyl vinyl ether is particularly preferable from the viewpoint of availability.
  • a monomer (5) may be used individually by 1 type, and may use 2 or more types together.
  • a vinyl ether monomer represented by the following formula (6) (hereinafter also referred to as “monomer (6)”) is used.
  • CH 2 CHOR 9 (6)
  • R 9 is a group that does not undergo deprotection reaction under the reaction conditions under which R 10 undergoes deprotection reaction.
  • the monomer (6) is a compound in which the hydrogen atom of the hydroxyl group of vinyl alcohol is substituted with R 9 .
  • R 9 is as already described for the unit (31).
  • the monomer (6) include alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, sec-butyl vinyl ether, cyclohexyl vinyl ether; hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, aminopropyl vinyl ether, Examples thereof include functional group-containing vinyl ethers such as glycidyl vinyl ether; fluorine-containing vinyl ethers such as heptafluoropentyl vinyl ether.
  • vinyl fluoride ethylene, propylene, isobutene or the like is used.
  • the copolymer (B) is obtained by radical polymerization of the monomer (4), the monomer (5), the monomer (6) used as necessary, vinyl fluoride or alkene.
  • Monomers (monomer (5) and monomer (6)) having a vinyl ether group or a vinyl ester group may cause isomerization, decomposition, or homocation polymerization under acidic conditions. Therefore, from the viewpoint of allowing the polymerization to proceed stably, radical polymerization is preferably performed under basic conditions, and the pH is particularly preferably 8-9.
  • a method of adjusting the pH in the polymerization to basic conditions a method of adding a basic compound to the reaction system is preferable.
  • Examples of basic compounds include alkali metal salts and ammonium salts of carbonic acid and phosphoric acid, and sodium carbonate, disodium hydrogen carbonate, potassium carbonate, dipotassium hydrogen carbonate, ammonium carbonate, phosphoric acid and the like in terms of easy availability.
  • Sodium, disodium hydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, ammonium phosphate and the like are preferable.
  • the usage-amount of a basic compound can be suitably changed according to the kind, reaction conditions, etc.
  • the monomer (6), vinyl fluoride and alkene are not used, 0.005 to 5% by mass is preferable with respect to the total mass of the monomer (4) and the monomer (5). 1 to 5% by mass is particularly preferred.
  • the total mass of the monomer (4), monomer (5), monomer (6), vinyl fluoride and alkene 0.005 to 5 mass% is preferable, and 0.1 to 5 mass% is particularly preferable.
  • the pH is a pH at room temperature (20 to 25 ° C.).
  • the molar ratio of the monomer (4), monomer (5) used for copolymerization, and monomer (6) used as necessary, vinyl fluoride or alkene is the unit in the copolymer (A) ( The molar ratios of 1), (2) and (3) are as described above.
  • radical polymerization initiator examples include a radical polymerization initiator or ionizing radiation.
  • a radical polymerization initiator examples include a water-soluble radical polymerization initiator or an oil-soluble radical polymerization initiator can be appropriately used depending on the polymerization type or the polymerization medium.
  • water-soluble radical polymerization initiator examples include (3-carboxypropionyl) peroxide (HOC ( ⁇ O) CH 2 CH 2 C ( ⁇ O) OOC ( ⁇ O) CH 2 CH 2 C ( ⁇ O) OH), Organic peroxides such as bis (4-carboxybutyryl) peroxide (HOC ( ⁇ O) CH 2 CH 2 CH 2 C ( ⁇ O) OOC ( ⁇ O) CH 2 CH 2 CH 2 C ( ⁇ O) OH)
  • An inorganic peroxide such as ammonium persulfate or potassium persulfate; a redox (oxidation-reduction reaction, a combination of an inorganic peroxide such as ammonium persulfate and a reducing agent such as hydrogen peroxide, sodium hydrogen sulfite, or sodium thiosulfate; redox) initiator; inorganic initiator in which a small amount of iron, ferrous salt, silver nitrate, etc.
  • disuccinic acid peroxide diglutarate Dibasic acid peroxides such as Le acid peroxide
  • organic radical polymerization initiator such as a dibasic acid salts such as azobisisobutylamidine the like.
  • oil-soluble radical polymerization initiator include peroxy ester type peroxides such as t-butyl peroxyacetate and t-butyl peroxypivalate; dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate; benzoyl peroxide; And azobisisobutylnitrile.
  • radical polymerization initiator t-butyl peroxypivalate (PBPV) or the like is preferable from the viewpoint of easy handling.
  • PBPV t-butyl peroxypivalate
  • a water-soluble radical polymerization initiator is preferable, an inorganic peroxide is preferable, and ammonium persulfate is particularly preferable in terms of easy handling.
  • a radical polymerization initiator may be used individually by 1 type, and may use 2 or more types together.
  • the amount of radical polymerization initiator used can be appropriately changed according to the type, polymerization conditions, etc., and is preferably 0.005 to 5% by mass, preferably 0.05 to 0%, based on the total amount of monomers used for copolymerization. .5% by mass is particularly preferred.
  • the polymerization format is not particularly limited, and bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization and the like can be employed. Among them, solution polymerization is preferable from the viewpoint that it is not necessary to add various additives and a copolymer with few impurities can be obtained. Emulsion polymerization is preferred from the viewpoint of obtaining a copolymer having a high molecular weight and a high alternating sequence ratio.
  • the polymerization medium aromatic compounds such as xylene and toluene, alcohols such as t-butyl alcohol, esters, fluorochlorocarbons and the like are preferable.
  • the amount of the polymerization medium is preferably 10 to 200% by mass, particularly preferably 50 to 100% by mass, based on the total amount of monomers used for copolymerization.
  • the polymerization method may be any of batch, continuous and semi-continuous methods.
  • the polymerization temperature can be appropriately selected depending on the radical polymerization initiation source, the polymerization medium, etc., is preferably ⁇ 30 to 150 ° C., more preferably 0 to 100 ° C., and particularly preferably 20 to 70 ° C.
  • the polymerization pressure can be appropriately selected according to the radical polymerization initiation source, the polymerization medium, and the like, preferably 0.1 to 10 MPa, particularly preferably 0.2 to 3 MPa.
  • the polymerization time is preferably 1 to 24 hours, particularly preferably 2 to 12 hours.
  • the water-based medium is preferably water alone because it is easily available.
  • various surfactants such as a cationic surfactant, an anionic surfactant and a nonionic surfactant can be used.
  • anionic surfactants such as sulfonic acid type surfactants, carboxylic acid type surfactants and phosphate ester type surfactants are preferred.
  • the sulfonic acid type surfactant include sodium lauryl sulfate and sodium dodecylbenzene sulfonate.
  • R 11 represents a C 1-9 perfluoroalkyl group which may contain an oxygen atom
  • n represents an integer of 0-2
  • X 2 represents a hydrogen atom, NH 4 or an alkali metal atom. .
  • R 11 preferably has 5 to 9 carbon atoms.
  • n is preferably 0 in that the effect of preventing a chain transfer reaction during polymerization is high.
  • X 2 is preferably a hydrogen atom or NH 4 , particularly preferably NH 4 .
  • ammonium perfluorooctanoate F (CF 2 ) 2 OCF 2 CF 2 OCF 2 COONH 4 , F (CF 2 ) 3 OCF 2 CF 2 OCF 2 COONH 4 , F (CF 2 ) 4 OCF 2 CF 2 OCF 2 COONH 4 is preferred.
  • the amount of emulsifier used can be appropriately changed according to the type, reaction conditions, and the like.
  • the amount is preferably 0.005 to 5% by mass relative to the total mass of the monomer (4) and the monomer (5). 1 to 5% by mass is particularly preferred.
  • the content is preferably 0.005 to 5% by mass, particularly preferably 0.1 to 5% by mass.
  • the weight average molecular weight (Mw) of the obtained copolymer (B) is 50,000 to 1,000,000, preferably 100,000 to 800,000, like the copolymer (A). 000 to 500,000 is particularly preferred. Further, the molecular weight distribution (Mw / Mn) of the copolymer (B) is preferably 1 to 5, and particularly preferably 1 to 3, like the copolymer (A).
  • Copolymer (A) having polymerized units based on monomer (4), polymerized units based on vinyl alcohol, and polymerized units based on monomer (6) (a copolymer in which OH and OR 9 are present as Z) Is obtained.
  • R 10 in the unit based on the monomer (5) of the copolymer (B) with a hydrogen atom by a deprotection reaction a protected alcohol by acid, base, heat or light, which is usually used, is used.
  • the deprotection reaction can be employed.
  • the deprotection reaction by an acid is preferable from the point which suppresses that the obtained copolymer (A) colors. That is, it is preferable to replace R 10 with a hydrogen atom with an acid.
  • the acid used for the deprotection reaction include inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as acetic acid, butyric acid and trifluoroacetic acid.
  • Examples of the base used for the deprotection reaction include inorganic base compounds such as sodium hydroxide, potassium hydroxide, aqueous ammonia, sodium methoxide, potassium methoxide, sodium ethoxide, and potassium ethoxide.
  • the deprotection reaction with acid includes (I) deprotection reaction in a mixed solution of sulfuric acid / ethanol / water, (II) deprotection reaction in a mixed solution of hydrochloric acid / dioxane, (III) trifluoroacetic acid / methylene chloride.
  • the deprotection reaction with an acid is not limited to the reaction systems (I) to (III) described above, and may be performed in an aqueous system or a non-aqueous system.
  • Examples of the photoacid generator include onium salts, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds. Specific examples include diphenyliodonium triflate, triphenylsulfonium triflate, phenyl-bis (trichloromethyl) -s-triazine, methoxyphenyl-bis (trichloromethyl) -s-triazine, 4-trisphenacylsulfone, 1, And 8-naphthalenedicarboxylic acid imide triflate.
  • the deprotection reaction may be terminated halfway before all the protecting groups of the copolymer (B) are deprotected.
  • a copolymer (A) having a unit based on the monomer (4), a unit based on the monomer (5), and a unit based on vinyl alcohol (a copolymer in which OH and OR 10 exist as Z). Polymer).
  • the copolymer (B) contains a unit based on the monomer (6), the unit based on the monomer (4) and the vinyl monomer can be obtained by terminating the deprotection reaction in the middle.
  • Copolymer (A) having a unit based on body (5), a unit based on vinyl alcohol, and a unit based on monomer (6) (a copolymer in which OH, OR 9 and OR 10 are present as Z) Is obtained.
  • the deprotection reaction is terminated halfway, the ratio of the unit based on the monomer (5) and the unit based on vinyl alcohol, or the unit based on the monomer (5) and the unit based on vinyl alcohol
  • the hydrophilicity and crystallinity of the resulting copolymer (A) can be adjusted by adjusting the ratio of the monomer and the unit based on the monomer (6).
  • the method for producing the separation membrane of the present invention is not particularly limited. For example, a method of drawing a hollow fiber obtained by melt spinning a copolymer (A), a non-solvent induced phase separation utilizing a phase separation phenomenon when a non-solvent is added to a solution containing the copolymer (A)
  • Examples include a thermally induced phase separation method using phase separation that occurs when the solution containing (A) is cooled.
  • the Rob-Thrilleryan method is preferred in that a separation membrane having an excellent salt rejection can be obtained.
  • a film of the liquid composition is formed from a liquid composition in which the copolymer (A) is dissolved or dispersed in a water-miscible organic solvent, and a part of the organic solvent is formed from the surface of the film of the liquid composition. It is preferable to convert the film of the liquid composition into a solid film by removing water to form a partially dried film and then replacing the remaining organic solvent with water.
  • the feature of this method is that a part of the organic solvent is removed from the surface of the liquid composition film to form a partially dry film, thereby forming a dense solid surface layer on the film surface, and then the remaining in the film. By replacing the organic solvent with water, the portion other than the surface layer of the partially dried membrane is made a porous solid layer.
  • Step (1) A step of obtaining a liquid composition from the copolymer (A) and a water-miscible organic solvent.
  • Process (2) The process of apply
  • Process (4) The process which makes the base material which has a partial dry film
  • the water-miscible organic solvent in the liquid composition is not limited as long as it can dissolve the copolymer (A) or can be dispersed at a nanoscale level.
  • Alcohols, amides, esters and carbonates It is preferably at least one selected from the group consisting of
  • the alcohol is preferably an alcohol having 1 to 10 carbon atoms, and examples thereof include alkanols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and t-butanol.
  • the amide, dialkylformamide having 3 to 7 carbon atoms, acetamido, pyrrolidone and the like are preferable, and examples thereof include dimethylformamide and N-methylpyrrolidone.
  • esters having 2 to 10 carbon atoms which may contain an etheric oxygen atom are preferable, and examples thereof include ethyl acetate and ethylene glycol monomethyl ether acetate.
  • carbonates having 3 to 7 carbon atoms are preferable, and examples thereof include dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.
  • the water-miscible organic solvent is more preferably an alkanol having 4 or less carbon atoms in view of easy substitution with water, and methanol, ethanol, and a mixture thereof are particularly preferable.
  • the liquid composition may contain a solvent (poor solvent) that does not dissolve the copolymer (A) for the purpose of adjusting the pore size of the membrane as long as the copolymer (A) does not precipitate.
  • the poor solvent include water, alkanes, and cycloalkanes. Of these, water is preferable because of its low cost.
  • the liquid composition may contain a hydrophilic compound such as a compound having a large number of hydroxyl groups (such as saccharides) or a compound having a carboxyl group for the purpose of improving hydrophilicity.
  • the content of the copolymer (A) in the liquid composition is preferably 5 to 50% by mass, particularly preferably 10 to 40% by mass. When the content is in the above range, a film of a good liquid composition can be obtained.
  • any stirring means can be used as the means for mixing the copolymer (A) and the water-miscible organic solvent.
  • any stirring means include a homomixer, a Henschel mixer, a Banbury mixer, and a pressure kneader.
  • a substrate is usually used to support the film of the liquid composition.
  • a film of the liquid composition can be formed on the substrate surface by spreading the liquid composition on the substrate surface by means such as coating.
  • the substrate include glass and plastic.
  • the casting method is preferable in that a film of a liquid composition having high film thickness uniformity and few foreign matters can be obtained.
  • the film thickness of the liquid composition is preferably such that the final film thickness is in the above range.
  • the organic solvent is removed by evaporation from the exposed surface of the film (the surface not in contact with the substrate). .
  • a solid layer of the copolymer (A) is formed on the exposed surface of the liquid composition film.
  • This solid surface layer is a non-porous layer or a dense layer (a layer having a small pore diameter) even if porous.
  • the method for removing the organic solvent from the liquid composition film in order to obtain a partially dried film is not particularly limited, depending on the organic solvent used, such as natural drying, air drying, heating, reduced pressure, heating under reduced pressure, etc. May be used.
  • the organic solvent is removed, for example, at a heating temperature of 50 ° C. for 60 seconds when ethanol is used as the solvent.
  • the amount of the organic solvent removed from the liquid composition film in order to obtain a partially dried film is preferably 20 to 70% by mass relative to the amount of the organic solvent before removal (100% by mass). As a result, a partially dried film containing 30 to 80% by mass of the organic solvent with respect to the amount of organic solvent (100% by mass) in the film of the liquid composition before removal is obtained.
  • the partially dried film obtained above is then brought into contact with water to replace the organic solvent in the partially dried film with water, and the entire film is made into a solid film.
  • the method of making it contact with water can be performed by immersing the base material which has a partially dried film
  • the water may be any of distilled water, ion exchange water, ultrapure water, and the like.
  • the water temperature is preferably 0 to 30 ° C.
  • the contact time can be appropriately adjusted depending on the thickness of the partially dried film, and is preferably 1 to 24 hours.
  • the fact that the organic solvent in the partially dried film was completely replaced with water is that the obtained film was immersed in a solvent different from the organic solvent used in the liquid composition, and the solvent after the immersion was analyzed by gas chromatography. This can be detected.
  • a solid porous layer is formed, thereby obtaining a heterogeneous film in which the porous layer is integrated with the dense surface layer formed during the formation of the partially dried film. .
  • the solid film formed on the substrate may be dehydrated together with the substrate, or the solid film may be peeled off from the substrate and then dehydrated.
  • membrane containing water may shrink
  • the dehydration method include heating, reduced pressure, and heating under reduced pressure, and heating is preferable in terms of simplicity.
  • the heating temperature is preferably 30 to 100 ° C. in that a separation membrane having an excellent salt rejection is obtained.
  • the following step (5) is preferred.
  • the obtained membrane For the purpose of adjusting the pore size of the obtained membrane, it may be heat-treated after the solid membrane is produced.
  • the temperature of the heat treatment is preferably lower than the decomposition start temperature of the film. Examples of the heat treatment include an oven and a hot plate.
  • Each measuring method used in the examples is as follows. (Mass average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn)) The mass average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the copolymer obtained in each example were measured using a high-speed GPC device “HLC-8220GPC” manufactured by Tosoh Corporation. It measured by the gel filtration chromatography (GPC) of gel conversion. Tetrahydrofuran was used as the eluent.
  • GPC gel filtration chromatography
  • Thermal properties of the copolymer The glass transition point (Tg) of the copolymer obtained in each example was measured using a differential scanning calorimeter “Q100” manufactured by TA Instruments, and the 10% mass loss temperature (Td10) was The measurement was performed using a simultaneous differential heat / thermal mass measurement apparatus “TG-DTA2000SA” manufactured by Bruker AXS.
  • Test test A dumbbell-shaped sample for tensile test with a length of 63 mm and a width of 3 mm was prepared, and a Tensilon universal testing machine “RTC-1210” manufactured by A & D Corporation was used. A tensile test was performed at a distance between marked lines of 10 mm and a test speed of 10 mm / min, and the elongation at break and the maximum point stress were measured.
  • dumbbell-shaped copolymer film was immersed in an aqueous sodium hypochlorite solution (effective chlorine concentration 1,000 ppm, pH 10) for 4 weeks at room temperature, washed with water, dried, and then the same method as above. A tensile test was performed.
  • TFE tetrafluoroethylene
  • copolymer (A1) A 500 mL flask was charged with 49 g of copolymer (B1), 49 g of 36 mass% concentrated hydrochloric acid, and 315 g of ethanol, and the mixture was heated and stirred at an internal temperature of 78 ° C. to carry out a substitution reaction. After the reaction was continued for 8 hours, the reaction solution was dropped into water to precipitate a copolymer, washed with water, and then vacuum dried at 90 ° C. to obtain a copolymer (hereinafter referred to as “copolymer (A1)”). ”) Was obtained. No coloring was seen in this step.
  • copolymer (B2) a solid of a copolymer
  • the yield of copolymer (B2) was 110 g, and the reaction rate of vinyl acetate was 45%.
  • copolymer (A2) A 100 mL flask was charged with 4.1 g of the copolymer (B2), 4.0 g of 36 mass% concentrated hydrochloric acid, and 52 g of ethanol, and the mixture was heated and stirred at an internal temperature of 78 ° C. for deprotection reaction. After the reaction was continued for 32 hours, the reaction solution was dropped into water to precipitate a copolymer, washed with water, and then vacuum dried at 90 ° C. to obtain a copolymer (hereinafter referred to as “copolymer (A2)”). 2.7 g of the product was obtained.
  • copolymer (B2) and copolymer (A2) it was confirmed from the 1 H NMR spectrum and 19 F NMR spectrum that 99% or more of the acetyl groups were replaced with hydrogen by hydrolysis to generate hydroxyl groups. .
  • Tg 85 degreeC and Td10 was 379 degreeC.
  • Example 1 The copolymer (A1) obtained in Synthesis Example 1 was dissolved in ethanol to obtain a 10% by mass solution. After applying this solution on a PTFE sheet, ethanol was completely evaporated to prepare a cast film (copolymer film) having a thickness of 50 ⁇ m. The film was subjected to water contact angle measurement, tensile test, and oxidation resistance property measurement. The copolymer film maintained both elongation and strength even after immersion in sodium hypochlorite, and did not lose the toughness of the film. Next, the copolymer (A1) was dissolved in ethanol to obtain a 20% by mass solution (liquid composition).
  • the solution is applied to a glass substrate (manufactured by Asahi Glass Co., Ltd., length 100 mm ⁇ width 100 mm ⁇ thickness 1 mm) to form a liquid composition film, and then the glass substrate having the liquid composition film is formed at 60 ° C. at 60 ° C. By heating for 2 seconds, a glass substrate having a partially dried film whose amount of solvent contained was 45% by mass of the amount of solvent before heating (100% by mass) was obtained. Subsequently, the partially dried film was immersed in water together with the glass substrate, ethanol was replaced with water, and a heterogeneous film containing water was obtained.
  • the heterogeneous film containing water was peeled from the glass substrate, and the surface zeta potential of the heterogeneous film was measured and a desalting test was performed.
  • the salt rejection was 5%, and it was confirmed that the salt rejection was excellent.
  • the evaluation results are shown in Table 1.
  • membrane containing water was measured with the micrometer, it was 70 micrometers.
  • Example 2 Using the copolymer (A2) obtained in Synthesis Example 2, a copolymer film having a thickness of 50 ⁇ m was prepared in the same manner as in Example 1, and a water contact angle measurement, a tensile test, and an oxidation resistance property measurement were performed. . The copolymer film decreased in elongation after immersion in sodium hypochlorite, but maintained its strength. Further, a heterogeneous film was produced in the same manner as in Example 1, and its physical properties were measured. The evaluation results are shown in Table 1. It was 75 micrometers when the thickness of the dry film obtained by removing water similarly to Example 1 was measured with the micrometer.
  • the heterogeneous film containing water was peeled from the glass substrate, and the water contact angle was measured and a desalting test was performed.
  • the water contact angle was 110 degrees, and water did not permeate.
  • the thickness of the dry film obtained by removing water was measured with a micrometer in the same manner as in Example 1, it was 65 ⁇ m.
  • the separation membrane of the present invention can be suitably applied to membranes for water treatment, battery separators, food production, medical use and the like.
  • the entire contents of the specification, claims and abstract of Japanese Patent Application No. 2012-262314 filed on November 30, 2012 are incorporated herein as the disclosure of the specification of the present invention. It is.

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Abstract

Provided is a separation membrane having excellent antifouling properties, hydrophilic properties, and oxidizing agent resistance, as well as excellent desalting performance necessary for application to seawater desalination. A separation membrane comprising a copolymer having a mass average molecular weight of 50,000-1,000,000 and including units represented by formula (1) and units represented by formula (2), in which the salt rejection ate by a cross-flow method is at least 3% at 25°C and 0.45 MPaG using an aqueous solution of sodium chloride having a concentration of 0.15% by mass. In formula (1), X and Y are each independently H, F, CF3, or Cl. In formula (2), Z is OR1, NHR2, COOR3, or SO3R4. In the formulae, R is a bivalent linking group which may include a single bond and an etheric oxygen atom, or a bivalent linking group which may include a ring structure, and R1-R4 are each independently H or a monovalent organic group. Of the units represented by formula (2) included in the copolymer, the ratio of units in which R1-R4 are H is at least 50 mol%.

Description

含フッ素共重合体からなる分離膜Separation membrane made of fluorine-containing copolymer
　本発明は、含フッ素共重合体からなる分離膜に関する。 The present invention relates to a separation membrane made of a fluorine-containing copolymer.
　従来から、分離膜は、河川、湖沼水の浄化用途、汚水、排水の処理用途、海水の淡水化用途、食品製造用途等に広く使用されている。これらの分離膜は使用中に不溶解性の物質が堆積し、膜の目詰まりを引き起こすため、一般に定期的に洗浄して使用される。特に洗浄困難なバイオファウリングに対しては、次亜塩素酸ソーダ等の酸化剤が用いられる。 Conventionally, separation membranes have been widely used for river and lake water purification applications, sewage and wastewater treatment applications, seawater desalination applications, food production applications, and the like. These separation membranes are generally used after being regularly cleaned because insoluble substances accumulate during use and cause clogging of the membrane. For biofouling that is particularly difficult to clean, an oxidizing agent such as sodium hypochlorite is used.
　近年、地球規模の人口増の影響で、飲料水および農業用水の確保が重要となり、特に海水淡水化に用いられる分離膜の開発が盛んに行われている。海水淡水化技術は、一部で既に実用化されており、膜材料としてはポリアミドと酢酸セルロースが使用されている。中でも薄い膜を作成でき、低い圧力で透水量を多くできる点で、ポリアミドが使用される。 In recent years, it has become important to secure drinking water and agricultural water under the influence of global population growth, and separation membranes used for seawater desalination are being actively developed. Seawater desalination technology has already been put into practical use in part, and polyamide and cellulose acetate are used as membrane materials. Among them, polyamide is used because a thin film can be formed and the amount of water permeation can be increased with a low pressure.
　しかし、ポリアミドは酸化分解するため（非特許文献１）、前述の次亜塩素酸ソーダに対する耐久性が不充分であり、様々の検討がなされている。例えば、ポリアミド膜表面を別のポリマーでコーティングすることにより、膜表面のゼータ電位を約０ｍＶに制御し、帯電した汚染物質の付着を防止し、ファウリングを抑制する方法が提案されている（特許文献１、２）。 However, since polyamide is oxidatively decomposed (Non-Patent Document 1), durability against the above-mentioned sodium hypochlorite is insufficient, and various studies have been made. For example, a method has been proposed in which the polyamide film surface is coated with another polymer to control the zeta potential of the film surface to about 0 mV, prevent adhesion of charged contaminants, and suppress fouling (patent) References 1, 2).
　一方、酸化剤に耐久性のある材料として、ポリフッ化ビニリデンが検討されている。例えば、ポリフッ化ビニリデンに親水性ポリマーをブレンドすることにより親水性を向上させ、ファウリングを抑制した多孔質膜（特許文献３）、ポリフッ化ビニリデンに分解反応で親水性化合物を発生させる親水化剤の分解物を含有してなる多孔質膜（特許文献４）が提案されている。また、テトラフルオロエチレンと酢酸ビニルとの共重合体に含まれるアセテート基の少なくとも一部をケン化した重合体を用いた分離膜（特許文献５）も提案されている。 On the other hand, polyvinylidene fluoride is being studied as a material that is durable to oxidizing agents. For example, a porous film that improves hydrophilicity by blending a hydrophilic polymer with polyvinylidene fluoride and suppresses fouling (Patent Document 3), and a hydrophilizing agent that generates a hydrophilic compound by a decomposition reaction of polyvinylidene fluoride A porous membrane containing a decomposition product of (Patent Document 4) has been proposed. In addition, a separation membrane using a polymer obtained by saponifying at least a part of an acetate group contained in a copolymer of tetrafluoroethylene and vinyl acetate (Patent Document 5) has also been proposed.
特開２００６－２３９６３６号公報JP 2006-239636 A 特許３３７９９６３号公報Japanese Patent No. 3379963 特許４６００１７２号公報Japanese Patent No. 4600172 特開２００５－２９６８４６号公報JP 2005-296846 A 特開平５－２６１２５６号公報JP-A-5-261256
　しかしながら、特許文献１、２に記載の方法は操作が煩雑であり、また、膜表面を全てコーティング膜で覆い尽くすには特殊な技術を必要とする。特許文献３に記載の多孔質膜では、使用中に、膜中から親水性ポリマーがブリードアウトし、膜の親水性が低下する恐れがある。特許文献４に記載の多孔質膜においても、発生した親水性化合物が膜中からブリードアウトする恐れがある。その他、放射線グラフト重合等によりポリフッ化ビニリデンを親水化する方法があるが、元来、ポリフッ化ビニリデン膜の水接触角は９０度前後と高く、疎水性の材料であるため、高い親水性を必要とするナノ濾過膜（ＮＦ膜）や逆浸透膜（ＲＯ膜）には適さない。特許文献５に記載の分離膜では、分離対象物質が生体物質等であり、ナノ濾過膜（ＮＦ膜）や逆浸透膜（ＲＯ膜）には適さない。 However, the methods described in Patent Documents 1 and 2 are complicated in operation, and a special technique is required to completely cover the film surface with the coating film. In the porous membrane described in Patent Document 3, during use, the hydrophilic polymer may bleed out from the membrane, and the hydrophilicity of the membrane may decrease. Also in the porous membrane described in Patent Document 4, the generated hydrophilic compound may bleed out from the membrane. In addition, there is a method of hydrophilizing polyvinylidene fluoride by radiation graft polymerization or the like. Originally, the water contact angle of the polyvinylidene fluoride film is as high as around 90 degrees, and it is a hydrophobic material, so high hydrophilicity is required. It is not suitable for nanofiltration membranes (NF membranes) and reverse osmosis membranes (RO membranes). In the separation membrane described in Patent Document 5, the substance to be separated is a biological material or the like, and is not suitable for a nanofiltration membrane (NF membrane) or a reverse osmosis membrane (RO membrane).
　本発明は、耐ファウリング性、親水性および酸化剤耐性に優れ、さらに、海水淡水化用途に必要な脱塩性能にも優れる分離膜の提供を目的とする。 The object of the present invention is to provide a separation membrane that is excellent in fouling resistance, hydrophilicity, and oxidant resistance, and also excellent in desalting performance required for seawater desalination.
　本発明は、以下［１］～［１５］の構成を有する分離膜、分離膜の製造方法、分離膜製造用組成物を提供する。
［１］下式（１）で表される単位と下式（２）で表される単位とを含み、質量平均分子量が５０，０００～１，０００，０００である共重合体からなり、０．１５質量％塩化ナトリウム水溶液を用いた、２５℃および０．４５ＭＰａＧにおけるクロスフロー方式での塩阻止率が少なくとも３％であることを特徴とする分離膜。
Figure JPOXMLDOC01-appb-C000003
 　式（１）中、ＸおよびＹは、それぞれ独立にＨ、Ｆ、ＣＦ３またはＣｌである。
　式（２）中、ＺはＯＲ１、ＮＨＲ２、ＣＯＯＲ３またはＳＯ３Ｒ４である。Ｒは単結合、エーテル性酸素原子を含んでもよい２価の連結基、または環構造を含んでもよい２価の連結基である。Ｒ１～Ｒ４は、それぞれ独立にＨまたは１価の有機基である。
　ただし、前記共重合体に含まれる式（２）で表される単位のうち、Ｒ１～Ｒ４がＨである単位の割合は５０モル％以上である。 The present invention provides a separation membrane having the following constitutions [1] to [15], a method for producing the separation membrane, and a composition for producing the separation membrane.
[1] A copolymer comprising a unit represented by the following formula (1) and a unit represented by the following formula (2) and having a mass average molecular weight of 50,000 to 1,000,000, A separation membrane having a salt rejection of at least 3% in a crossflow method at 25 ° C. and 0.45 MPaG using a 15 mass% sodium chloride aqueous solution.
Figure JPOXMLDOC01-appb-C000003
 In formula (1), X and Y are each independently H, F, CF 3 or Cl.
In the formula (2), Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 . R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure. R 1 to R 4 are each independently H or a monovalent organic group.
However, the proportion of units in which R 1 to R 4 are H among the units represented by the formula (2) contained in the copolymer is 50 mol% or more.
［２］前記共重合体において、式（１）で表される単位と式（２）で表される単位のモル比が、４０／６０～６０／４０である、［１］の分離膜。
［３］前記共重合体において、式（１）で表される単位と式（２）で表される単位との交互配列率が９５％以上である、［１］または［２］の分離膜。
［４］前記共重合体において、ＸがＦであり、ＹがＦまたはＣｌである、［１］～［３］のいずれかの分離膜。
［５］前記共重合体において、ＺがＯＲ１である、［１］～［４］のいずれかの分離膜。
［６］前記共重合体において、Ｒが単結合、Ｏ（ＣＨ２）ｎまたは（ＯＣＨ２ＣＨ２）ｍである（ただしｎは２～４の整数であり、ｍは１～４の整数である。）、［１］～［５］のいずれかの分離膜。
［７］分離膜が、浄水処理用または海水淡水化処理用の膜である、［１］～［６］のいずれかの分離膜。 [2] The separation membrane according to [1], wherein the molar ratio of the unit represented by the formula (1) to the unit represented by the formula (2) in the copolymer is 40/60 to 60/40.
[3] The separation membrane according to [1] or [2], wherein in the copolymer, the alternating arrangement ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is 95% or more. .
[4] The separation membrane according to any one of [1] to [3], wherein in the copolymer, X is F and Y is F or Cl.
[5] The separation membrane according to any one of [1] to [4], wherein Z is OR 1 in the copolymer.
[6] In the copolymer, R is a single bond, O (CH 2 ) n or (OCH 2 CH 2 ) m (where n is an integer of 2 to 4, and m is an integer of 1 to 4) Or a separation membrane according to any one of [1] to [5].
[7] The separation membrane according to any one of [1] to [6], wherein the separation membrane is a membrane for water purification treatment or seawater desalination treatment.
［８］前記［１］～［６］のいずれかの分離膜を製造する方法であって、
　前記共重合体が水混和性の有機溶媒に溶解ないし分散されている液状組成物から該液状組成物の膜を形成し、該液状組成物の膜の表面から有機溶媒の一部を除去して部分乾燥膜を形成し、次いで、残余の有機溶媒を水に置換することにより前記液状組成物の膜を固体の膜に変換することを特徴とする分離膜の製造方法。
［９］前記水混和性の有機溶媒が、アルコール類、アミド類、エステル類およびカーボネート類からなる群より選ばれる少なくとも１種の有機溶媒である、［８］の分離膜の製造方法。
［１０］前記水混和性の有機溶媒が炭素数４以下のアルカノールである、［８］または［９］の分離膜の製造方法。
［１１］下記工程（１）～（４）を含む、［８］～［１０］のいずれかの分離膜の製造方法。
　工程（１）：前記共重合体と前記水混和性の有機溶媒から前記液状組成物を得る工程。
　工程（２）：基材表面に前記液状組成物を塗布して、基材表面上に液状組成物の膜を形成する工程。
　工程（３）：前記基材表面上の液状組成物の膜の表面から前記有機溶媒の一部を除去し、有機溶媒除去前の液状組成物膜中の有機溶媒量（１００質量％）に対して３０～８０質量％の有機溶媒を含有する部分乾燥膜を形成する工程。
　工程（４）：前記部分乾燥膜を有する基材を水と接触させて、前記有機溶媒を水に置換し、水を含有する固体状の膜を形成する工程。
［１２］さらに下記工程（５）を含む、［１１］の分離膜の製造方法。
　工程（５）：前記水を含有する固体状膜を３０～１００℃の温度に加熱する工程。 [8] A method for producing the separation membrane according to any one of [1] to [6],
A film of the liquid composition is formed from a liquid composition in which the copolymer is dissolved or dispersed in a water-miscible organic solvent, and a part of the organic solvent is removed from the surface of the liquid composition film. A method for producing a separation membrane, wherein a membrane of the liquid composition is converted into a solid membrane by forming a partially dried membrane and then substituting the remaining organic solvent with water.
[9] The method for producing a separation membrane according to [8], wherein the water-miscible organic solvent is at least one organic solvent selected from the group consisting of alcohols, amides, esters and carbonates.
[10] The method for producing a separation membrane according to [8] or [9], wherein the water-miscible organic solvent is an alkanol having 4 or less carbon atoms.
[11] The method for producing a separation membrane according to any one of [8] to [10], comprising the following steps (1) to (4):
Step (1): A step of obtaining the liquid composition from the copolymer and the water-miscible organic solvent.
Process (2): The process of apply | coating the said liquid composition on the base-material surface, and forming the film | membrane of a liquid composition on a base-material surface.
Step (3): A part of the organic solvent is removed from the surface of the liquid composition film on the substrate surface, and the amount of the organic solvent (100% by mass) in the liquid composition film before removing the organic solvent. Forming a partially dried film containing 30 to 80% by mass of an organic solvent.
Step (4): A step of bringing the substrate having the partially dried film into contact with water, replacing the organic solvent with water, and forming a solid film containing water.
[12] The method for producing a separation membrane according to [11], further comprising the following step (5).
Step (5): A step of heating the solid film containing water to a temperature of 30 to 100 ° C.
［１３］下式（１）で表される単位と下式（２）で表される単位とを含み、質量平均分子量が５０，０００～１，０００，０００である共重合体が、水混和性の有機溶媒に溶解ないし分散されている液状組成物であることを特徴とする分離膜製造用の液状組成物。
Figure JPOXMLDOC01-appb-C000004
 　式（１）中、ＸおよびＹは、それぞれ独立にＨ、Ｆ、ＣＦ３またはＣｌである。
　式（２）中、ＺはＯＲ１、ＮＨＲ２、ＣＯＯＲ３またはＳＯ３Ｒ４である。Ｒは単結合、エーテル性酸素原子を含んでもよい２価の連結基、または環構造を含んでもよい２価の連結基である。Ｒ１～Ｒ４は、それぞれ独立にＨまたは１価の有機基である。
　ただし、前記共重合体に含まれる式（２）で表される単位のうち、Ｒ１～Ｒ４がＨである単位の割合は５０モル％以上である。
［１４］前記水混和性の有機溶媒が、アルコール類、アミド類、エステル類およびカーボネート類からなる群より選ばれる少なくとも１種の有機溶媒である、［１３］の分離膜製造用の液状組成物。
［１５］前記水混和性の有機溶媒が炭素数４以下のアルカノールである、［１３］または［１４］の分離膜製造用の液状組成物。 [13] A copolymer containing a unit represented by the following formula (1) and a unit represented by the following formula (2) and having a mass average molecular weight of 50,000 to 1,000,000 is mixed with water: A liquid composition for producing a separation membrane, which is a liquid composition dissolved or dispersed in a functional organic solvent.
Figure JPOXMLDOC01-appb-C000004
 In formula (1), X and Y are each independently H, F, CF 3 or Cl.
In the formula (2), Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 . R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure. R 1 to R 4 are each independently H or a monovalent organic group.
However, the proportion of units in which R 1 to R 4 are H among the units represented by the formula (2) contained in the copolymer is 50 mol% or more.
[14] The liquid composition for producing a separation membrane according to [13], wherein the water-miscible organic solvent is at least one organic solvent selected from the group consisting of alcohols, amides, esters and carbonates. .
[15] The liquid composition for producing a separation membrane according to [13] or [14], wherein the water-miscible organic solvent is an alkanol having 4 or less carbon atoms.
　本発明の分離膜は、耐ファウリング性、親水性および酸化剤耐性に優れ、さらに、海水淡水化用途に必要な脱塩性能にも優れる。 The separation membrane of the present invention has excellent fouling resistance, hydrophilicity and oxidant resistance, and also has excellent desalting performance required for seawater desalination.
［分離膜］
　本発明の分離膜は、０．１５質量％塩化ナトリウム水溶液を用いた、２５℃および０．４５ＭＰａＧ（絶対圧）におけるクロスフロー方式での塩阻止率が少なくとも３％である。濾過対象の塩化ナトリウム水溶液の量が、濾液に対し充分に多い場合、該塩阻止率は、下式により求められる。
　［（０．１５－濾液中の塩化ナトリウム濃度（質量％））／０．１５］×１００（％）上記濾液中の塩化ナトナトリウム濃度は、例えば電気伝導度から求めることができ、その詳細は実施例に示す。塩阻止率が３％以上であれば、海水淡水化、かん水の脱塩、食品製造等の用途に好適に使用できる。塩阻止率の好ましい範囲は使用目的にもよるが、５％以上が特に好ましい。 [Separation membrane]
The separation membrane of the present invention has a salt rejection of at least 3% in a cross flow method at 25 ° C. and 0.45 MPaG (absolute pressure) using a 0.15 mass% sodium chloride aqueous solution. When the amount of sodium chloride aqueous solution to be filtered is sufficiently large relative to the filtrate, the salt rejection is obtained by the following equation.
[(0.15-sodium chloride concentration in the filtrate (% by mass)) / 0.15] × 100 (%) The sodium sodium chloride concentration in the filtrate can be determined from, for example, the electrical conductivity. It is shown in the examples. If the salt rejection is 3% or more, it can be suitably used for applications such as seawater desalination, brine desalination, and food production. Although the preferable range of the salt rejection depends on the purpose of use, it is particularly preferably 5% or more.
　該分離膜は、２５℃および０．４５ＭＰａＧにおける濾過流束が、１０Ｌ／ｍ２・ｄａｙ以上であることが好ましい。濾過流束が上記範囲であれば、海水淡水化、かん水の脱塩、食品製造等の用途に好適に使用できる。濾過流束は、５０Ｌ／ｍ２・ｈ以上がより好ましく、１００Ｌ／ｍ２・ｈ以上が特に好ましい。 The separation membrane preferably has a filtration flux at 25 ° C. and 0.45 MPaG of 10 L / m 2 · day or more. If the filtration flux is in the above range, it can be suitably used for applications such as seawater desalination, brine demineralization, and food production. Filtration flux is more preferably at least 50L / m 2 · h, more 100L / m 2 · h are particularly preferred.
　該分離膜の表面の２５℃におけるゼータ電位は、帯電した物質の付着を抑制でき、目詰まりを防止できる点（耐ファウリング性）から、－１０ｍＶ～＋１０ｍＶが好ましく、－５ｍＶ～＋５ｍＶが特に好ましい。ゼータ電位が上記範囲であれば、海水淡水化、かん水の脱塩、食品製造等の用途に好適である。 The zeta potential at 25 ° C. on the surface of the separation membrane is preferably −10 mV to +10 mV, and particularly preferably −5 mV to +5 mV, from the viewpoint that adhesion of charged substances can be suppressed and clogging can be prevented (fouling resistance). . When the zeta potential is in the above range, it is suitable for uses such as seawater desalination, brine demineralization, and food production.
　分離膜の膜厚は用途に応じて適宜選択できるが、乾燥状態（水を含有しない状態）で、０．１μｍ～１ｍｍが好ましく、１～５００μｍがより好ましく、１～１００μｍが特に好ましい。 The thickness of the separation membrane can be appropriately selected depending on the application, but is preferably 0.1 μm to 1 mm, more preferably 1 to 500 μm, and particularly preferably 1 to 100 μm in a dry state (state not containing water).
　本発明の分離膜は、後述するように式（１）で表される単位と式（２）で表される単位とを含み、質量平均分子量が５０，０００～１，０００，０００である共重合体（以下、「共重合体（Ａ）」ともいう。）からなる。共重合体（Ａ）を用いることで、分離膜は親水性および酸化剤への耐久性に優れる。
　本発明の分離膜は、強度を向上でき、分離膜の膜厚を薄くすることができる点から、共重合体（Ａ）と共に他の材料を複合化して製造してもよい。該他の材料としては、ポリエチレン、ポリプロピレン、ポリスルホン、ポリエーテルスルホン、ポリアクリロニトリル、ポリビニリデンフルオリド、ポリテトラフルオロエチレン、酢酸セルロース、ポリアミド等の有機材料、セラミック等の無機材料が挙げられる。複合化方法としては、共重合体（Ａ）の中空糸と他の材料の中空糸とを織り込んで分離膜を形成する方法、共重合体（Ａ）と他の材料との混合物から分離膜を得る方法、他の材料により作製した分離膜上に形成する方法等が挙げられる。共重合体（Ａ）と共に他の材料を複合化して得られる分離膜の膜厚においては、乾燥状態（水を含有しない状態）で、０．０１～１００μｍが好ましく、０．０５～５０μｍが特に好ましい。 The separation membrane of the present invention comprises a unit represented by the formula (1) and a unit represented by the formula (2) as described later, and has a mass average molecular weight of 50,000 to 1,000,000. A polymer (hereinafter also referred to as “copolymer (A)”). By using the copolymer (A), the separation membrane is excellent in hydrophilicity and durability to an oxidizing agent.
The separation membrane of the present invention may be manufactured by combining other materials together with the copolymer (A) from the viewpoint that the strength can be improved and the thickness of the separation membrane can be reduced. Examples of the other materials include organic materials such as polyethylene, polypropylene, polysulfone, polyethersulfone, polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, cellulose acetate, and polyamide, and inorganic materials such as ceramic. As a composite method, a separation membrane is formed by weaving a hollow fiber of the copolymer (A) and a hollow fiber of another material, and a separation membrane is formed from a mixture of the copolymer (A) and another material. And a method of forming on a separation membrane made of other materials. The thickness of the separation membrane obtained by compositing other materials with the copolymer (A) is preferably 0.01 to 100 μm, particularly 0.05 to 50 μm in a dry state (containing no water). preferable.
［含フッ素共重合体（共重合体（Ａ））］
　本発明における含フッ素共重合体（共重合体（Ａ））は、下式（１）で表される単位（以下、「単位（１）」ともいう。）と、下式（２）で表される単位（以下、「単位（２）」ともいう。）との共重合体からなる。 [Fluorine-containing copolymer (copolymer (A))]
The fluorine-containing copolymer (copolymer (A)) in the present invention is represented by the unit represented by the following formula (1) (hereinafter also referred to as “unit (1)”) and the following formula (2). And a unit (hereinafter also referred to as “unit (2)”).
Figure JPOXMLDOC01-appb-C000005
 　式（１）中、ＸおよびＹは、それぞれ独立にＨ、Ｆ、ＣＦ３またはＣｌである。
　式（２）中、ＺはＯＲ１、ＮＨＲ２、ＣＯＯＲ３またはＳＯ３Ｒ４である。Ｒは単結合、エーテル性酸素原子を含んでもよい２価の連結基、または環構造を含んでもよい２価の連結基である。Ｒ１～Ｒ４は、それぞれ独立にＨまたは１価の有機基である。
　ただし、前記共重合体に含まれる単位（２）のうち、Ｒ１～Ｒ４がＨである単位の割合は５０モル％以上である。
Figure JPOXMLDOC01-appb-C000005
 In formula (1), X and Y are each independently H, F, CF 3 or Cl.
In the formula (2), Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 . R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure. R 1 to R 4 are each independently H or a monovalent organic group.
However, of the units (2) contained in the copolymer, the proportion of units in which R 1 to R 4 are H is 50 mol% or more.
　単位（１）は疎水性を有する単位である。
　式（１）中、Ｘは単位（１）の疎水性が高くなる点から、Ｆが好ましい。共重合体（Ａ）中に存在するＸは、１種類でも２種類以上でもよいが、安定的に製造できる点で１種類が好ましい。
　Ｙは単位（１）の疎水性に優れる点からは、Ｆが好ましい。また、共重合体（Ａ）が耐熱性に優れる点からは、Ｃｌが好ましい。共重合体（Ａ）中に存在するＹは、１種類でも２種類以上でもよいが、安定的に製造できる点で１種類が好ましい。
　単位（１）としては、単量体の入手容易の点から、ＸがＦであり、ＹがＦまたはＣｌである単位が好ましい。 Unit (1) is a unit having hydrophobicity.
In the formula (1), X is preferably F because the hydrophobicity of the unit (1) is increased. One type or two or more types of X present in the copolymer (A) may be used, but one type is preferable in terms of stable production.
Y is preferably F from the viewpoint of excellent hydrophobicity of the unit (1). Moreover, Cl is preferable from the point that a copolymer (A) is excellent in heat resistance. Y present in the copolymer (A) may be one type or two or more types, but one type is preferable in terms of stable production.
The unit (1) is preferably a unit in which X is F and Y is F or Cl from the viewpoint of easy availability of the monomer.
　前記共重合体（Ａ）に含まれる単位（２）のうち、Ｒ１～Ｒ４がＨである単位の割合は、共重合体（Ａ）が親水性に優れる点で、７０～１００モル％が好ましく、８５～１００モル％が特に好ましい。 Of the units (2) contained in the copolymer (A), the proportion of units in which R 1 to R 4 are H is 70 to 100 mol% in that the copolymer (A) is excellent in hydrophilicity. Is preferred, with 85 to 100 mol% being particularly preferred.
　ＺはＯＲ１が好ましく、ＯＨが特に好ましい。
　共重合体（Ａ）中に存在するＺは１種類でも２種類以上でもよいが、安定的に製造できる点で１種類が好ましい。 Z is preferably OR 1 and particularly preferably OH.
One type or two or more types of Z present in the copolymer (A) may be used, but one type is preferable in terms of stable production.
　Ｒ１～Ｒ４における１価の有機基としては、エーテル性酸素原子を含んでもよい炭素数１～６の第１級もしくは第２級のアルキル基、または該アルキル基の水素原子の１個以上が置換基で置換された基が好ましい。該アルキル基は、直鎖状、分岐状のいずれであってもよい。前記置換基としては、水酸基、アミノ基、グリシジル基等の官能基、フッ素原子等が挙げられる。
　Ｒ１～Ｒ４における１価の有機基は、－ＣＲ５Ｒ６Ｒ７（Ｒ５、Ｒ６およびＲ７は、それぞれ独立に炭素数１～３のアルキル基である。）、炭素数１～６のアルコキシメチル基、テトラヒドロフリル基、テトラヒドロピラニル基、炭素数２～６のアシル基、または－Ｓｉ（Ｒ８）３（Ｒ８は炭素数１～６のアルキル基またはアリール基である。）であってもよい。 The monovalent organic group in R 1 to R 4 is a primary or secondary alkyl group having 1 to 6 carbon atoms which may contain an etheric oxygen atom, or one or more hydrogen atoms of the alkyl group Is preferably a group substituted with a substituent. The alkyl group may be linear or branched. As said substituent, functional groups, such as a hydroxyl group, an amino group, and a glycidyl group, a fluorine atom, etc. are mentioned.
The monovalent organic group in R 1 to R 4 is —CR 5 R 6 R 7 (R 5 , R 6 and R 7 are each independently an alkyl group having 1 to 3 carbon atoms), and 1 carbon atom. ˜6 alkoxymethyl group, tetrahydrofuryl group, tetrahydropyranyl group, acyl group having 2 to 6 carbon atoms, or —Si (R 8 ) 3 (R 8 is an alkyl group or aryl group having 1 to 6 carbon atoms) .).
　Ｒは単結合、エーテル性酸素原子を含んでもよい２価の連結基、または環構造を含んでもよい２価の連結基である。
　エーテル性酸素原子を含んでもよい２価の連結基としては、炭素数が１～１００のアルキレン基またはエーテル性酸素原子を含む炭素数が１～１００のアルキレン基が好ましく、炭素数が１～５０のアルキレン基またはエーテル性酸素原子を含む炭素数が１～５０のアルキレン基がより好ましく、炭素数が１～１０のアルキレン基またはエーテル性酸素原子を含む炭素数が１～１０のアルキレン基が特に好ましい。
　環構造を含んでもよい２価の連結基としては、シクロヘキシレン基またはエーテル性酸素原子を含むシクロヘキシレン基が好ましい。
　Ｒは、共重合体（Ａ）が親水性に優れる点で、単結合、Ｏ（ＣＨ２）ｎまたは（ＯＣＨ２ＣＨ２）ｍである（ただしｎは２～４の整数であり、ｍは１～４の整数である。）ことが好ましい。
　共重合体（Ａ）中に存在する複数のＲは、１種類でも２種類以上でもよいが、安定的に製造できる点で１種類が好ましい。 R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure.
The divalent linking group which may contain an etheric oxygen atom is preferably an alkylene group having 1 to 100 carbon atoms or an alkylene group containing 1 to 100 carbon atoms containing an etheric oxygen atom, and has 1 to 50 carbon atoms. More preferably an alkylene group having 1 to 50 carbon atoms containing an etheric oxygen atom, particularly an alkylene group having 1 to 10 carbon atoms or an alkylene group having 1 to 10 carbon atoms containing an etheric oxygen atom. preferable.
The divalent linking group that may contain a ring structure is preferably a cyclohexylene group or a cyclohexylene group containing an etheric oxygen atom.
R is a single bond, O (CH 2 ) n or (OCH 2 CH 2 ) m in the point that the copolymer (A) is excellent in hydrophilicity, where n is an integer of 2 to 4, and m is It is preferably an integer of 1 to 4.
The plurality of Rs present in the copolymer (A) may be one type or two or more types, but one type is preferable in that it can be stably produced.
　共重合体（Ａ）としては、単位（１）として、ＸがＦ、ＹがＦまたはＣｌである単位を有し、単位（２）として、ＺがＯＲ１、Ｒが単結合、Ｏ（ＣＨ２）ｎまたは（ＯＣＨ２ＣＨ２）ｍである単位（ただしｎは２～４の整数、ｍは１～４の整数）を有するものが好ましい。Ｒ１としては、前記－ＣＲ５Ｒ６Ｒ７または炭素数２～６のアシル基が好ましく、中でも－ＣＲ５Ｒ６Ｒ７が特に好ましい。 The copolymer (A) has a unit in which X is F and Y is F or Cl as a unit (1), Z is OR 1 , R is a single bond, O (CH 2 ) Those having units of n or (OCH 2 CH 2 ) m (where n is an integer of 2 to 4 and m is an integer of 1 to 4) are preferred. As R 1 , the above-mentioned —CR 5 R 6 R 7 or an acyl group having 2 to 6 carbon atoms is preferable, and —CR 5 R 6 R 7 is particularly preferable.
　共重合体（Ａ）の質量平均分子量（Ｍｗ）は、５０，０００～１，０００，０００であり、１００，０００～８００，０００が好ましく、１００，０００～５００，０００が特に好ましい。質量平均分子量が上記範囲の下限値以上であれば、強度に優れた分離膜が得られ、上限値以下であれば、均質な分離膜が形成できる。なお、質量平均分子量（Ｍｗ）は、ポリスチレン標準を用いたＧＰＣにより測定することができる。 The mass average molecular weight (Mw) of the copolymer (A) is from 50,000 to 1,000,000, preferably from 100,000 to 800,000, particularly preferably from 100,000 to 500,000. If the mass average molecular weight is not less than the lower limit of the above range, a separation membrane excellent in strength can be obtained, and if it is not more than the upper limit, a homogeneous separation membrane can be formed. The mass average molecular weight (Mw) can be measured by GPC using a polystyrene standard.
　共重合体（Ａ）の分子量分布（Ｍｗ／Ｍｎ）は１～５が好ましく、１～３が特に好ましい。上記範囲の上限値以下であると、ゲル物質も少なく、強度に優れた分離膜を形成できる。 The molecular weight distribution (Mw / Mn) of the copolymer (A) is preferably from 1 to 5, particularly preferably from 1 to 3. When the amount is not more than the upper limit of the above range, a gel material is less and a separation membrane having excellent strength can be formed.
　共重合体（Ａ）は、単位（１）および単位（２）のみから構成されることが好ましいが、本発明の効果を損なわない範囲で、単位（１）および単位（２）に加えて、単位（３）を含んでいてもよい。単位（３）としては、単位（２）以外のビニルエステルに基づく単位、単位（２）以外のアルキル基の結合したビニルエーテルに基づく単位、フッ化ビニルまたはアルケンに基づく単位等が挙げられる。共重合体（Ａ）の靭性を高める点では、アルキル基の結合したビニルエーテルに基づく単位、分離膜の強度を高める点では、フッ化ビニルまたはアルケンに基づく単位が好ましい。なお、単位（３）としては、２５℃における共重合体（Ａ）のゼータ電位を－１０ｍＶ～＋１０ｍＶ程度にできる点で、イオン性の官能基を有しない単位が好ましい。 The copolymer (A) is preferably composed only of the unit (1) and the unit (2), but in addition to the unit (1) and the unit (2) as long as the effects of the present invention are not impaired, The unit (3) may be included. Examples of the unit (3) include units based on vinyl esters other than the unit (2), units based on vinyl ethers to which alkyl groups other than the unit (2) are bonded, units based on vinyl fluoride or alkenes, and the like. From the viewpoint of increasing the toughness of the copolymer (A), a unit based on an alkyl group-bonded vinyl ether and a unit based on vinyl fluoride or an alkene are preferable from the viewpoint of increasing the strength of the separation membrane. The unit (3) is preferably a unit having no ionic functional group in that the zeta potential of the copolymer (A) at 25 ° C. can be about −10 mV to +10 mV.
　単位（２）以外のアルキル基の結合したビニルエーテルに基づく単位としては、下式（３１）で表される単位（３１）が好ましい。
Figure JPOXMLDOC01-appb-C000006
 　ただし、式（３１）中、Ｒ９は置換されていてよい、炭素数１～６の第一級または第二級アルキル基および炭素数６～１２のシクロアルキル基からなる群より選ばれる基であり、例えば、メチル基、エチル基、ｎ－ブチル基、イソブチル基、ｓｅｃ－ブチル基、シクロヘキシル基、ヒドロキシエチル基、ヒドロキシブチル基、ヘプタフルオロペンチル基等が挙げられる。該置換基としては、水酸基アミノ基、グリシジル基、フッ素原子等が挙げられる。 As a unit based on vinyl ether to which an alkyl group other than unit (2) is bonded, unit (31) represented by the following formula (31) is preferable.
Figure JPOXMLDOC01-appb-C000006
 In the formula (31), R 9 is an optionally substituted group selected from the group consisting of a primary or secondary alkyl group having 1 to 6 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms. Examples thereof include a methyl group, an ethyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a cyclohexyl group, a hydroxyethyl group, a hydroxybutyl group, and a heptafluoropentyl group. Examples of the substituent include a hydroxyl group amino group, a glycidyl group, and a fluorine atom.
　アルケンに基づく単位として好ましい単位は、エチレン、プロピレンまたはイソブテンに基づく単位である。 Preferred units as units based on alkenes are units based on ethylene, propylene or isobutene.
　共重合体に含まれる各単位のモル比は、単位（３）が含まれない場合、単位（１）／単位（２）は２５／７５～７５／２５が好ましく、４０／６０～６０／４０がより好ましく、４５／５５～５５／４５がさらに好ましく、５０／５０が特に好ましい。 When the unit (3) is not included, the molar ratio of each unit contained in the copolymer is preferably 25/75 to 75/25, preferably 40/60 to 60/40. Is more preferable, 45/55 to 55/45 is more preferable, and 50/50 is particularly preferable.
　単位（３）が含まれる場合、単位（１）／［単位（２）＋単位（３）］のモル比が４０／６０～６０／４０であることが好ましく、４５／５５～５５／４５がより好ましく、５０／５０が特に好ましい。また、単位（２）／単位（３）のモル比は、４５／５～２５／２５が好ましく、４０／１０～２５／２５が特に好ましい。 When the unit (3) is contained, the molar ratio of unit (1) / [unit (2) + unit (3)] is preferably 40/60 to 60/40, and 45/55 to 55/45 is More preferably, 50/50 is particularly preferable. The molar ratio of unit (2) / unit (3) is preferably 45/5 to 25/25, particularly preferably 40/10 to 25/25.
　共重合体（Ａ）が単位（３）を含まない場合には、単位（１）と単位（２）との交互配列率が８０％以上であることが好ましく、９５％以上がより好ましく、９７％以上が特に好ましい。共重合体（Ａ）が単位（３）を含む場合には、単位（１）と、単位（２）または（３）との交互配列率が８０％以上であることが好ましく、交互配列率が９５％以上がより好ましく、９７％以上が特に好ましい。
　共重合体（Ａ）の交互配列率が上記範囲であると、分離膜の強度および伸度に優れる。また単位（２）が均一に存在するため、分離膜の親水性に優れる。 When the copolymer (A) does not contain the unit (3), the alternating arrangement ratio of the unit (1) and the unit (2) is preferably 80% or more, more preferably 95% or more, and 97 % Or more is particularly preferable. When the copolymer (A) contains the unit (3), the alternating arrangement ratio of the unit (1) and the unit (2) or (3) is preferably 80% or more, and the alternating arrangement ratio is 95% or more is more preferable, and 97% or more is particularly preferable.
When the alternating arrangement ratio of the copolymer (A) is in the above range, the strength and elongation of the separation membrane are excellent. Further, since the unit (2) exists uniformly, the hydrophilicity of the separation membrane is excellent.
　共重合体の交互配列率とは、隣り合う２つの単位の組み合わせ数の合計に対する、異なる単量体に基づく単位が隣り合っている組み合わせ数の比率である。例えば、共重合体が１・２・１・２・２・１・２・１・２・１・２で表されるもの（ただし、１は単位（１）を示し、２は単位（２）を示す。）である場合、隣り合う２つの単位の組み合わせ数は１０であり、異なる単量体に基づく単位が隣り合っている組み合わせ数が９であるので、交互配列率は９０％である。該交互配列率は、当該共重合体の合成に用いる複数種の単量体の重合反応性比から求められる。各単量体の重合反応性が低くかつ近い場合に、交互配列率が向上する。 The alternating arrangement ratio of the copolymer is the ratio of the number of combinations in which units based on different monomers are adjacent to the total number of combinations of two adjacent units. For example, the copolymer is represented by 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2 (where 1 represents unit (1) and 2 represents unit (2) ), The number of combinations of two adjacent units is 10, and the number of combinations in which units based on different monomers are adjacent is 9, so that the alternating arrangement ratio is 90%. The alternating sequence ratio is determined from the polymerization reactivity ratio of plural types of monomers used for the synthesis of the copolymer. When the polymerization reactivity of each monomer is low and close, the alternating sequence ratio is improved.
［含フッ素共重合体の製造方法］
　共重合体（Ａ）の製造方法は、単位（１）および（２）を形成するための単量体を用いて、公知の方法から選択できる。該方法としては、例えば下記方法（ｉ）、（ｉｉ）等が挙げられる。
　（ｉ）重合すると単位（１）を形成する単量体と、単位（２）を形成する単量体とを共重合させる方法。
　（ｉｉ）重合により単位（１）を形成する単量体と、化学反応（脱保護反応等）により単位（２）となる単位を形成する単量体とを共重合体させた後、得られた共重合体を化学反応させて目的とする共重合体を得る方法。
　（ｉ）および（ｉｉ）のいずれを選択するかは、単位（２）中のＺを考慮して選択される。例えばＺがＯＨの場合は（ｉ）または（ｉｉ）、ＮＨ２の場合は（ｉ）または（ｉｉ）、ＣＯＯＨの場合は（ｉｉ）、ＳＯ３Ｈの場合は（ｉｉ）の方法が好ましく用いられる。 [Method for producing fluorine-containing copolymer]
The manufacturing method of a copolymer (A) can be selected from a well-known method using the monomer for forming unit (1) and (2). Examples of the method include the following methods (i) and (ii).
(I) A method of copolymerizing a monomer that forms unit (1) upon polymerization and a monomer that forms unit (2).
(Ii) obtained by copolymerizing a monomer that forms the unit (1) by polymerization and a monomer that forms the unit (2) by a chemical reaction (such as deprotection reaction). A method of obtaining a desired copolymer by chemically reacting the copolymer.
Which of (i) and (ii) is selected is selected in consideration of Z in the unit (2). For example, the method (i) or (ii) is preferably used when Z is OH, (i) or (ii) is used when NH 2 is used, (ii) is used when COOH is used, and the method (ii) is used when SO 3 H is used. It is done.
　以下に、ＺがＯＲ１である場合の共重合体（Ａ）の製造方法の好ましい実施形態を説明する。該方法は、下記重合工程および脱保護工程を含む。
　重合工程：下式（４）で表される含フッ素オレフィン（以下、「単量体（４）」ともいう。）と、下式（５）で表されるビニル系単量体（以下、「単量体（５）」ともいう。）とを共重合させる工程。
　脱保護工程：前記重合工程で得られた共重合体における単量体（５）に基づく重合単位のＲ１０を水素原子に置換し、水酸基を生じさせる工程。
　ＣＦ２＝ＣＸＹ　　　（４）
　ＣＨ２＝ＣＨＯＲ１０　　　（５）
（ただし、式（４）中、ＸおよびＹはそれぞれ独立にＨ、Ｆ、ＣＦ３またはＣｌである。式（５）中、Ｒ１０は脱保護反応により水素原子に置換される保護基である。） Below, preferable embodiment of the manufacturing method of a copolymer (A) in case Z is OR 1 is described. The method includes the following polymerization step and deprotection step.
Polymerization step: a fluorine-containing olefin represented by the following formula (4) (hereinafter, also referred to as “monomer (4)”) and a vinyl monomer represented by the following formula (5) (hereinafter, “ A step of copolymerizing with the monomer (5) ”.
Deprotection step: a step of substituting R 10 of the polymerization unit based on the monomer (5) in the copolymer obtained in the polymerization step with a hydrogen atom to generate a hydroxyl group.
CF 2 = CXY (4)
CH 2 = CHOR 10 (5)
(In the formula (4), X and Y are each independently H, F, CF 3 or Cl. In the formula (5), R 10 is a protecting group substituted by a hydrogen atom by a deprotection reaction. .)
　上記製造方法は、重合工程において単量体（４）に基づく単位と、単量体（５）に基づく単位を有する含フッ素オレフィン／ビニル系単量体共重合体（以下、「共重合体（Ｂ）」ともいう。）を得た後、共重合体（Ｂ）における単量体（５）に基づく単位のＲ１０を脱保護反応により水素原子に置換することで、含フッ素オレフィンに基づく単位と、ビニルアルコールに基づく単位とを有する共重合体（Ａ）を得る方法である。 In the polymerization step, a fluorine-containing olefin / vinyl monomer copolymer (hereinafter referred to as “copolymer”) having a unit based on the monomer (4) and a unit based on the monomer (5) in the polymerization step. B) ”)), and then the unit based on the fluorinated olefin is obtained by substituting R 10 of the unit based on the monomer (5) in the copolymer (B) with a hydrogen atom by a deprotection reaction. And a copolymer (A) having units based on vinyl alcohol.
（重合工程）
　重合工程では、単量体（４）と単量体（５）とを共重合させることにより、単量体（４）に基づく単位と単量体（５）に基づく単位とを有する共重合体（Ｂ）を得る。 (Polymerization process)
In the polymerization step, a copolymer having a unit based on the monomer (4) and a unit based on the monomer (5) by copolymerizing the monomer (4) and the monomer (5). (B) is obtained.
　単量体（４）の具体例としては、テトラフルオロエチレン、クロロトリフルオロエチレン、ヘキサフルオロプロピレン等が挙げられる。中でも、耐熱性に優れる点から、テトラフルオロエチレンまたはクロロトリフルオロエチレンが好ましく、テトラフルオロエチレンが特に好ましい。
　単量体（４）は、１種を単独で使用してもよく、２種以上を併用してもよい。 Specific examples of the monomer (4) include tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and the like. Of these, tetrafluoroethylene or chlorotrifluoroethylene is preferred, and tetrafluoroethylene is particularly preferred from the viewpoint of excellent heat resistance.
A monomer (4) may be used individually by 1 type, and may use 2 or more types together.
　単量体（５）におけるＲ１０は、水酸基をエーテルまたはエステルとして保護する保護基であり、次の脱保護工程で行う脱保護反応により水素原子に置換される基である。Ｒ１０が脱保護反応により水素原子に置換されると水酸基を生じる。
　Ｒ１０としては、有機化学分野で通常用いられる保護基が使用でき、入手容易の点で、－ＣＲ５Ｒ６Ｒ７、炭素数１～６のアルコキシメチル基、テトラヒドロフリル基、テトラヒドロピラニル基、炭素数２～６のアシル基または－Ｓｉ（Ｒ８）３が好ましく、－ＣＲ５Ｒ６Ｒ７と炭素数２～６のアシル基がより好ましく、－ＣＲ５Ｒ６Ｒ７が特に好ましい。ここで、Ｒ５、Ｒ６、Ｒ７およびＲ８は、単位（２）について、既に説明したとおりである。 R 10 in the monomer (5) is a protecting group that protects a hydroxyl group as an ether or an ester, and is a group that is substituted with a hydrogen atom by a deprotection reaction performed in the next deprotection step. When R 10 is substituted with a hydrogen atom by a deprotection reaction, a hydroxyl group is formed.
As R 10 , a protecting group usually used in the field of organic chemistry can be used. From the viewpoint of availability, —CR 5 R 6 R 7 , an alkoxymethyl group having 1 to 6 carbon atoms, a tetrahydrofuryl group, a tetrahydropyranyl group In addition, an acyl group having 2 to 6 carbon atoms or —Si (R 8 ) 3 is preferable, —CR 5 R 6 R 7 and an acyl group having 2 to 6 carbon atoms are more preferable, and —CR 5 R 6 R 7 is particularly preferable. . Here, R 5 , R 6 , R 7 and R 8 are as already described for the unit (2).
　単量体（５）としては、ｔ－ブチルビニルエーテル、１，１－ジメチルプロピルビニルエーテル、メトキシメチルビニルエーテル、テトラヒドロフリルビニルエーテル、テトラヒドロピラニルビニルエーテル、ビニロキシトリメチルシランまたはビニロキシジメチルフェニルシラン等のビニルエーテル、酢酸ビニル等のカルボン酸ビニルエステルが好ましい。得られる共重合体（Ａ）の交互配列率が９５％以上にできる点から、ビニルエーテルがより好ましく、入手容易の点で、ｔ－ブチルビニルエーテルが特に好ましい。
　単量体（５）は、１種を単独で使用してもよく、２種以上を併用してもよい。 Examples of the monomer (5) include t-butyl vinyl ether, 1,1-dimethylpropyl vinyl ether, methoxymethyl vinyl ether, tetrahydrofuryl vinyl ether, tetrahydropyranyl vinyl ether, vinyl ether such as vinyloxytrimethylsilane or vinyloxydimethylphenylsilane, acetic acid Carboxylic acid vinyl esters such as vinyl are preferred. Vinyl ether is more preferable from the viewpoint that the alternating copolymerization ratio of the obtained copolymer (A) can be 95% or more, and t-butyl vinyl ether is particularly preferable from the viewpoint of availability.
A monomer (5) may be used individually by 1 type, and may use 2 or more types together.
　単位（３）として好ましい単位（３１）を形成する場合には、下式（６）で表されるビニルエーテル系単量体（以下、「単量体（６）」ともいう。）を用いる。
　ＣＨ２＝ＣＨＯＲ９　　　（６）
（ただし、式（６）中、Ｒ９は前記Ｒ１０が脱保護反応する反応条件で脱保護反応しない基である。）
　単量体（６）は、ビニルアルコールの水酸基の水素原子がＲ９で置換されている化合物である。Ｒ９については、単位（３１）について、既に説明したとおりである。 In the case of forming a preferred unit (31) as the unit (3), a vinyl ether monomer represented by the following formula (6) (hereinafter also referred to as “monomer (6)”) is used.
CH 2 = CHOR 9 (6)
(However, in Formula (6), R 9 is a group that does not undergo deprotection reaction under the reaction conditions under which R 10 undergoes deprotection reaction.)
The monomer (6) is a compound in which the hydrogen atom of the hydroxyl group of vinyl alcohol is substituted with R 9 . R 9 is as already described for the unit (31).
　単量体（６）の具体例としては、メチルビニルエーテル、エチルビニルエーテル、ｎ－ブチルビニルエーテル、イソブチルビニルエーテル、ｓｅｃ－ブチルビニルエーテル、シクロヘキシルビニルエーテル等のアルキルビニルエーテル；ヒドロキシエチルビニルエーテル、ヒドロキシブチルビニルエーテル、アミノプロピルビニルエーテル、グリシジルビニルエーテル等の官能基含有ビニルエーテル；ヘプタフルオロペンチルビニルエーテル等の含フッ素ビニルエーテル等が挙げられる。 Specific examples of the monomer (6) include alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, sec-butyl vinyl ether, cyclohexyl vinyl ether; hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, aminopropyl vinyl ether, Examples thereof include functional group-containing vinyl ethers such as glycidyl vinyl ether; fluorine-containing vinyl ethers such as heptafluoropentyl vinyl ether.
　単位（３）としてフッ化ビニルまたはアルケンに基づく単位を形成する場合には、フッ化ビニル、エチレン、プロピレンまたはイソブテン等を用いる。 When forming a unit based on vinyl fluoride or alkene as the unit (3), vinyl fluoride, ethylene, propylene, isobutene or the like is used.
　単量体（４）、単量体（５）、および必要に応じて用いる単量体（６）、フッ化ビニルまたはアルケンをラジカル重合させることにより、共重合体（Ｂ）が得られる。
　ビニルエーテル基やビニルエステル基を有する単量体（単量体（５）および単量体（６））は、酸性条件下において、異性化、分解あるいは単独カチオン重合を起こすおそれがある。そのため、重合を安定に進行させる点から、塩基性条件下でラジカル重合を行うことが好ましく、ｐＨを８～９とすることが特に好ましい。
　重合におけるｐＨを塩基性条件に調節する方法としては、反応系に塩基性化合物を添加する方法が好ましい。塩基性化合物としては、炭酸、リン酸の、アルカリ金属塩、アンモニウム塩等が挙げられ、入手容易の点で、炭酸ナトリウム、炭酸水素２ナトリウム、炭酸カリウム、炭酸水素２カリウム、炭酸アンモニウム、リン酸ナトリウム、リン酸水素２ナトリウム、リン酸２水素ナトリウム、リン酸カリウム、リン酸水素２カリウム、リン酸２水素カリウム、リン酸アンモニウム等が好ましい。
　塩基性化合物の使用量は、その種類、反応条件等に応じて適宜変更できる。単量体（６）、フッ化ビニルおよびアルケンを用いない場合は、単量体（４）と単量体（５）の合計質量に対して、０．００５～５質量％が好ましく、０．１～５質量％が特に好ましい。単量体（６）、フッ化ビニルおよびアルケンを用いる場合は、単量体（４）、単量体（５）、単量体（６）、フッ化ビニルおよびアルケンの合計質量に対して、０．００５～５質量％が好ましく、０．１～５質量％が特に好ましい。
　なお、該ｐＨは、室温（２０～２５℃）におけるｐＨである。また、共重合体（Ｂ）の分子量を調節するため、連鎖移動剤を添加してもよい。 The copolymer (B) is obtained by radical polymerization of the monomer (4), the monomer (5), the monomer (6) used as necessary, vinyl fluoride or alkene.
Monomers (monomer (5) and monomer (6)) having a vinyl ether group or a vinyl ester group may cause isomerization, decomposition, or homocation polymerization under acidic conditions. Therefore, from the viewpoint of allowing the polymerization to proceed stably, radical polymerization is preferably performed under basic conditions, and the pH is particularly preferably 8-9.
As a method of adjusting the pH in the polymerization to basic conditions, a method of adding a basic compound to the reaction system is preferable. Examples of basic compounds include alkali metal salts and ammonium salts of carbonic acid and phosphoric acid, and sodium carbonate, disodium hydrogen carbonate, potassium carbonate, dipotassium hydrogen carbonate, ammonium carbonate, phosphoric acid and the like in terms of easy availability. Sodium, disodium hydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, ammonium phosphate and the like are preferable.
The usage-amount of a basic compound can be suitably changed according to the kind, reaction conditions, etc. When the monomer (6), vinyl fluoride and alkene are not used, 0.005 to 5% by mass is preferable with respect to the total mass of the monomer (4) and the monomer (5). 1 to 5% by mass is particularly preferred. When using the monomer (6), vinyl fluoride and alkene, the total mass of the monomer (4), monomer (5), monomer (6), vinyl fluoride and alkene, 0.005 to 5 mass% is preferable, and 0.1 to 5 mass% is particularly preferable.
The pH is a pH at room temperature (20 to 25 ° C.). Moreover, in order to adjust the molecular weight of a copolymer (B), you may add a chain transfer agent.
　共重合に用いる単量体（４）、単量体（５）、および必要に応じて用いる単量体（６）、フッ化ビニルまたはアルケンのモル比は、共重合体（Ａ）における単位（１）、（２）、（３）のモル比に関して、既に述べたとおりである。 The molar ratio of the monomer (4), monomer (5) used for copolymerization, and monomer (6) used as necessary, vinyl fluoride or alkene is the unit in the copolymer (A) ( The molar ratios of 1), (2) and (3) are as described above.
　ラジカル重合開始源としては、ラジカル重合開始剤または電離性放射線が挙げられる。
　ラジカル重合開始剤としては、重合形式または重合媒体に応じて、水溶性ラジカル重合開始剤または油溶性ラジカル重合開始剤を適宜使用できる。
　水溶性ラジカル重合開始剤としては、例えば、（３－カルボキシプロピオニル）ペルオキシド（ＨＯＣ（＝Ｏ）ＣＨ２ＣＨ２Ｃ（＝Ｏ）ＯＯＣ（＝Ｏ）ＣＨ２ＣＨ２Ｃ（＝Ｏ）ＯＨ）、ビス（４－カルボキシブチリル）ペルオキシド（ＨＯＣ（＝Ｏ）ＣＨ２ＣＨ２ＣＨ２Ｃ（＝Ｏ）ＯＯＣ（＝Ｏ）ＣＨ２ＣＨ２ＣＨ２Ｃ（＝Ｏ）ＯＨ）等の有機過酸化物；過硫酸アンモニウム、過硫酸カリウム等の無機過酸化物；過硫酸アンモニウム等の無機過酸化物と、過酸化水素、亜硫酸水素ナトリウム、チオ硫酸ナトリウム等の還元剤との組み合わせからなるレドックス（酸化還元反応、ｒｅｄｏｘ）開始剤；前記レドックス開始剤に少量の鉄、第一鉄塩、硝酸銀等を共存させた無機系開始剤；またはジコハク酸パーオキシド、ジグルタール酸パーオキシド等の２塩基酸過酸化物；アゾビスイソブチルアミジン等の２塩基酸塩等の有機系ラジカル重合開始剤が挙げられる。
　油溶性ラジカル重合開始剤としては、ｔ－ブチルパーオキシアセテート、ｔ－ブチルパーオキシピバレート等のパーオキシエステル型過酸化物；ジイソプロピルパーオキシジカーボネート等のジアルキルパーオキシジカーボネート；ベンゾイルパーオキシド；アゾビスイソブチルニトリル等が挙げられる。
　ラジカル重合開始剤としては、取り扱い容易の点で、ｔ－ブチルパーオキシピバレート（ＰＢＰＶ）等が好ましい。乳化重合の場合には、水溶性ラジカル重合開始剤が好ましく、取り扱い容易の点で、無機過酸化物が好ましく、過硫酸アンモニウムが特に好ましい。 Examples of the radical polymerization initiator include a radical polymerization initiator or ionizing radiation.
As the radical polymerization initiator, a water-soluble radical polymerization initiator or an oil-soluble radical polymerization initiator can be appropriately used depending on the polymerization type or the polymerization medium.
Examples of the water-soluble radical polymerization initiator include (3-carboxypropionyl) peroxide (HOC (═O) CH 2 CH 2 C (═O) OOC (═O) CH 2 CH 2 C (═O) OH), Organic peroxides such as bis (4-carboxybutyryl) peroxide (HOC (═O) CH 2 CH 2 CH 2 C (═O) OOC (═O) CH 2 CH 2 CH 2 C (═O) OH) An inorganic peroxide such as ammonium persulfate or potassium persulfate; a redox (oxidation-reduction reaction, a combination of an inorganic peroxide such as ammonium persulfate and a reducing agent such as hydrogen peroxide, sodium hydrogen sulfite, or sodium thiosulfate; redox) initiator; inorganic initiator in which a small amount of iron, ferrous salt, silver nitrate, etc. coexists in the redox initiator; or disuccinic acid peroxide, diglutarate Dibasic acid peroxides such as Le acid peroxide; organic radical polymerization initiator such as a dibasic acid salts such as azobisisobutylamidine the like.
Examples of the oil-soluble radical polymerization initiator include peroxy ester type peroxides such as t-butyl peroxyacetate and t-butyl peroxypivalate; dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate; benzoyl peroxide; And azobisisobutylnitrile.
As the radical polymerization initiator, t-butyl peroxypivalate (PBPV) or the like is preferable from the viewpoint of easy handling. In the case of emulsion polymerization, a water-soluble radical polymerization initiator is preferable, an inorganic peroxide is preferable, and ammonium persulfate is particularly preferable in terms of easy handling.
　ラジカル重合開始剤は、１種を単独で使用してもよく、２種以上を併用してもよい。
　ラジカル重合開始剤の使用量は、その種類、重合条件等に応じて適宜変更でき、共重合に用いる単量体の全量に対して、０．００５～５質量％が好ましく、０．０５～０．５質量％が特に好ましい。 A radical polymerization initiator may be used individually by 1 type, and may use 2 or more types together.
The amount of radical polymerization initiator used can be appropriately changed according to the type, polymerization conditions, etc., and is preferably 0.005 to 5% by mass, preferably 0.05 to 0%, based on the total amount of monomers used for copolymerization. .5% by mass is particularly preferred.
　重合形式としては、特に限定されず、塊状重合、懸濁重合、乳化重合、溶液重合等が採用できる。中でも、様々の添加剤を入れる必要がなく、不純物の少ない共重合体が得られる点からは、溶液重合が好ましい。高い分子量および高い交互配列率の共重合体が得られる点からは、乳化重合が好ましい。
　重合媒体としては、キシレン、トルエン等の芳香族化合物、ｔ－ブチルアルコール等のアルコール類、エステル類、フロロクロロカーボン類等が好ましい。
　重合媒体の量は、共重合に用いる単量体の全量に対して、１０～２００質量％が好ましく、５０～１００質量％が特に好ましい。
　また、重合方式としては、回分式、連続式、半連続式のいずれの形式で行ってもよい。 The polymerization format is not particularly limited, and bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization and the like can be employed. Among them, solution polymerization is preferable from the viewpoint that it is not necessary to add various additives and a copolymer with few impurities can be obtained. Emulsion polymerization is preferred from the viewpoint of obtaining a copolymer having a high molecular weight and a high alternating sequence ratio.
As the polymerization medium, aromatic compounds such as xylene and toluene, alcohols such as t-butyl alcohol, esters, fluorochlorocarbons and the like are preferable.
The amount of the polymerization medium is preferably 10 to 200% by mass, particularly preferably 50 to 100% by mass, based on the total amount of monomers used for copolymerization.
The polymerization method may be any of batch, continuous and semi-continuous methods.
　重合温度は、ラジカル重合開始源、重合媒体等に応じて適宜最適値が選択でき、－３０～１５０℃が好ましく、０～１００℃がより好ましく、２０～７０℃が特に好ましい。
　重合圧力は、ラジカル重合開始源、重合媒体等に応じて適宜選択でき、０．１～１０ＭＰａが好ましく、０．２～３ＭＰａが特に好ましい。
　重合時間は、１～２４時間が好ましく、２～１２時間が特に好ましい。 The polymerization temperature can be appropriately selected depending on the radical polymerization initiation source, the polymerization medium, etc., is preferably −30 to 150 ° C., more preferably 0 to 100 ° C., and particularly preferably 20 to 70 ° C.
The polymerization pressure can be appropriately selected according to the radical polymerization initiation source, the polymerization medium, and the like, preferably 0.1 to 10 MPa, particularly preferably 0.2 to 3 MPa.
The polymerization time is preferably 1 to 24 hours, particularly preferably 2 to 12 hours.
　乳化重合を行う場合、水性媒体としては、入手容易な点で水のみが好ましい。
　乳化剤としては、種々の界面活性剤、例えば陽イオン性界面活性剤、陰イオン性界面活性剤およびノニオン性界面活性剤等を使用できる。中でも、陰イオン性界面活性剤、例えばスルホン酸型界面活性剤、カルボン酸型界面活性剤およびリン酸エステル型界面活性剤等が好ましい。
　スルホン酸型界面活性剤としては、ラウリル硫酸ナトリウム、ドデシルベンゼンスルホン酸ナトリウム等が挙げられる。
　カルボン酸型界面活性剤としては、単量体（４）との親和性から含フッ素系カルボン酸型界面活性剤がより好ましく、入手容易の点で、下式（７）で表される化合物が特に好ましい。
　Ｒ１１－（ＣＨ２）ｎ－ＣＯＯＸ２　　　（７）
　（ただし、式（７）中、Ｒ１１は酸素原子を含んでもよい炭素数１～９のペルフルオロアルキル基、ｎは０～２の整数、Ｘ２は水素原子、ＮＨ４またはアルカリ金属原子を表す。）
　良好なミセル構造を形成する点から、Ｒ１１の炭素数は５～９が好ましい。また、重合中の連鎖移動反応を防ぐ効果が高い点で、ｎは０が好ましい。Ｘ２は水素原子またはＮＨ４が好ましく、ＮＨ４が特に好ましい。 When emulsion polymerization is performed, the water-based medium is preferably water alone because it is easily available.
As the emulsifier, various surfactants such as a cationic surfactant, an anionic surfactant and a nonionic surfactant can be used. Among these, anionic surfactants such as sulfonic acid type surfactants, carboxylic acid type surfactants and phosphate ester type surfactants are preferred.
Examples of the sulfonic acid type surfactant include sodium lauryl sulfate and sodium dodecylbenzene sulfonate.
As the carboxylic acid type surfactant, a fluorine-containing carboxylic acid type surfactant is more preferable from the viewpoint of the affinity with the monomer (4), and the compound represented by the following formula (7) is easily available. Particularly preferred.
R 11 — (CH 2 ) n —COOX 2 (7)
(In the formula (7), R 11 represents a C 1-9 perfluoroalkyl group which may contain an oxygen atom, n represents an integer of 0-2, X 2 represents a hydrogen atom, NH 4 or an alkali metal atom. .)
In view of forming a good micelle structure, R 11 preferably has 5 to 9 carbon atoms. Further, n is preferably 0 in that the effect of preventing a chain transfer reaction during polymerization is high. X 2 is preferably a hydrogen atom or NH 4 , particularly preferably NH 4 .
　乳化剤としては、ペルフルオロオクタン酸アンモニウム、Ｆ（ＣＦ２）２ＯＣＦ２ＣＦ２ＯＣＦ２ＣＯＯＮＨ４、Ｆ（ＣＦ２）３ＯＣＦ２ＣＦ２ＯＣＦ２ＣＯＯＮＨ４、Ｆ（ＣＦ２）４ＯＣＦ２ＣＦ２ＯＣＦ２ＣＯＯＮＨ４が好ましい。 As the emulsifier, ammonium perfluorooctanoate, F (CF 2 ) 2 OCF 2 CF 2 OCF 2 COONH 4 , F (CF 2 ) 3 OCF 2 CF 2 OCF 2 COONH 4 , F (CF 2 ) 4 OCF 2 CF 2 OCF 2 COONH 4 is preferred.
　乳化剤の使用量は、その種類、反応条件等に応じて適宜変更できる。単量体（６）、フッ化ビニルまたはアルケンを用いない場合は、単量体（４）と単量体（５）の合計質量に対して、０．００５～５質量％が好ましく、０．１～５質量％が特に好ましい。単量体（６）、フッ化ビニルおよびアルケンの少なくとも一種を用いる場合は、単量体（４）、単量体（５）、単量体（６）、フッ化ビニルおよびアルケンの合計質量に対して、０．００５～５質量％が好ましく、０．１～５質量％が特に好ましい。該量が上記範囲の下限値以上であると、安定な乳化状態を形成でき、上記範囲の上限値以下であると、激しく泡立つことがなく、安定に重合を進行できる。 The amount of emulsifier used can be appropriately changed according to the type, reaction conditions, and the like. When the monomer (6), vinyl fluoride or alkene is not used, the amount is preferably 0.005 to 5% by mass relative to the total mass of the monomer (4) and the monomer (5). 1 to 5% by mass is particularly preferred. When using at least one of monomer (6), vinyl fluoride and alkene, the total mass of monomer (4), monomer (5), monomer (6), vinyl fluoride and alkene On the other hand, the content is preferably 0.005 to 5% by mass, particularly preferably 0.1 to 5% by mass. When the amount is not less than the lower limit of the above range, a stable emulsified state can be formed, and when the amount is not more than the upper limit of the above range, polymerization can proceed stably without vigorous foaming.
　得られる共重合体（Ｂ）の質量平均分子量（Ｍｗ）は、前記共重合体（Ａ）と同様、５０，０００～１，０００，０００であり、１００，０００～８００，０００が好ましく、１００，０００～５００，０００が特に好ましい。また、共重合体（Ｂ）の分子量分布（Ｍｗ／Ｍｎ）も、前記共重合体（Ａ）と同様、１～５が好ましく、１～３が特に好ましい。 The weight average molecular weight (Mw) of the obtained copolymer (B) is 50,000 to 1,000,000, preferably 100,000 to 800,000, like the copolymer (A). 000 to 500,000 is particularly preferred. Further, the molecular weight distribution (Mw / Mn) of the copolymer (B) is preferably 1 to 5, and particularly preferably 1 to 3, like the copolymer (A).
（脱保護工程）
　脱保護工程では、前記重合工程で得られた共重合体（Ｂ）における単量体（５）に基づく単位のＲ１０を脱保護反応により水素原子に置換し、水酸基を生じさせる。これにより、単量体（５）に基づく単位がビニルアルコールに基づく単位に変換され、単量体（４）に基づく単位とビニルアルコールに基づく単位を有する共重合体（Ａ）（ＺとしてＯＨが存在する共重合体）が得られる。共重合体（Ｂ）に単量体（６）に基づく単位が含まれている場合は、該単量体（６）に基づく単位のＲ９は脱保護反応せずそのまま維持されるので、単量体（４）に基づく重合単位、ビニルアルコールに基づく重合単位、および単量体（６）に基づく重合単位を有する共重合体（Ａ）（ＺとしてＯＨおよびＯＲ９が存在する共重合体）が得られる。 (Deprotection process)
In the deprotection step, R 10 of the unit based on the monomer (5) in the copolymer (B) obtained in the polymerization step is replaced with a hydrogen atom by a deprotection reaction to generate a hydroxyl group. Thereby, the unit based on the monomer (5) is converted into a unit based on the vinyl alcohol, and the copolymer (A) having a unit based on the monomer (4) and a unit based on the vinyl alcohol (wherein OH is Z Present copolymer). When the copolymer (B) contains a unit based on the monomer (6), R 9 of the unit based on the monomer (6) is maintained as it is without deprotection. Copolymer (A) having polymerized units based on monomer (4), polymerized units based on vinyl alcohol, and polymerized units based on monomer (6) (a copolymer in which OH and OR 9 are present as Z) Is obtained.
　共重合体（Ｂ）の単量体（５）に基づく単位におけるＲ１０を脱保護反応により水素原子に置換する方法としては、通常行われる、酸、塩基、熱あるいは光による、保護化したアルコールの脱保護反応が採用できる。中でも、得られる共重合体（Ａ）が着色することを抑制しやすい点から、酸による脱保護反応が好ましい。すなわち、酸によってＲ１０を水素原子に置換することが好ましい。
　脱保護反応に用いる酸としては、硫酸、塩酸、硝酸等の無機酸、酢酸、酪酸、トリフルオロ酢酸等の有機酸等が挙げられる。
　脱保護反応に用いる塩基としては、水酸化ナトリウム、水酸化カリウム、アンモニア水、ナトリウムメトキシド、カリウムメトキシド、ナトリウムエトキシド、カリウムエトキシド等の無機塩基化合物が挙げられる。 As a method for substituting R 10 in the unit based on the monomer (5) of the copolymer (B) with a hydrogen atom by a deprotection reaction, a protected alcohol by acid, base, heat or light, which is usually used, is used. The deprotection reaction can be employed. Especially, the deprotection reaction by an acid is preferable from the point which suppresses that the obtained copolymer (A) colors. That is, it is preferable to replace R 10 with a hydrogen atom with an acid.
Examples of the acid used for the deprotection reaction include inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as acetic acid, butyric acid and trifluoroacetic acid.
Examples of the base used for the deprotection reaction include inorganic base compounds such as sodium hydroxide, potassium hydroxide, aqueous ammonia, sodium methoxide, potassium methoxide, sodium ethoxide, and potassium ethoxide.
　酸による脱保護反応は、（Ｉ）硫酸／エタノール／水の混合溶液中での脱保護反応、（ＩＩ）塩酸／ジオキサンの混合溶液中での脱保護反応、（ＩＩＩ）トリフルオロ酢酸／塩化メチレンの混合溶液中での脱保護反応が好ましい。ただし、酸による脱保護反応は、前記（Ｉ）～（ＩＩＩ）の反応系には限定されず、水系で行ってもよく、非水系で行ってもよい。
　また、酸による脱保護反応は、光の照射により酸を発生する光酸発生剤を用いて行ってもよい。光酸発生剤としては、例えば、オニウム塩、ハロゲン含有化合物、ジアゾケトン化合物、スルホン化合物、スルホン酸化合物等が挙げられる。具体例としては、ジフェニルヨードニウムトリフレート、トリフェニルスルホニウムトリフレート、フェニル－ビス（トリクロロメチル）－ｓ－トリアジン、メトキシフェニル－ビス（トリクロロメチル）－ｓ－トリアジン、４－トリスフェナシルスルホン、１，８－ナフタレンジカルボン酸イミドトリフレート等が挙げられる。 The deprotection reaction with acid includes (I) deprotection reaction in a mixed solution of sulfuric acid / ethanol / water, (II) deprotection reaction in a mixed solution of hydrochloric acid / dioxane, (III) trifluoroacetic acid / methylene chloride. Deprotection reaction in a mixed solution of However, the deprotection reaction with an acid is not limited to the reaction systems (I) to (III) described above, and may be performed in an aqueous system or a non-aqueous system.
Moreover, you may perform the deprotection reaction by an acid using the photo-acid generator which generate | occur | produces an acid by irradiation of light. Examples of the photoacid generator include onium salts, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds. Specific examples include diphenyliodonium triflate, triphenylsulfonium triflate, phenyl-bis (trichloromethyl) -s-triazine, methoxyphenyl-bis (trichloromethyl) -s-triazine, 4-trisphenacylsulfone, 1, And 8-naphthalenedicarboxylic acid imide triflate.
　脱保護工程においては、共重合体（Ｂ）が有する全ての保護基が脱保護される前に脱保護反応を途中で終了してもよい。この場合、単量体（４）に基づく単位と、単量体（５）に基づく単位と、ビニルアルコールに基づく単位とを有する共重合体（Ａ）（ＺとしてＯＨおよびＯＲ１０が存在する共重合体）が得られる。
　共重合体（Ｂ）に単量体（６）に基づく単位が含まれている場合は、脱保護反応を途中で終了させることにより、単量体（４）に基づく単位と、ビニル系単量体（５）に基づく単位と、ビニルアルコールに基づく単位と、単量体（６）に基づく単位を有する共重合体（Ａ）（ＺとしてＯＨ、ＯＲ９およびＯＲ１０が存在する共重合体）が得られる。
　上記のように、脱保護反応を途中で終了させて、単量体（５）に基づく単位とビニルアルコールに基づく単位との比率、または単量体（５）に基づく単位とビニルアルコールに基づく単位と単量体（６）に基づく単位との比率を調節することにより、得られる共重合体（Ａ）の親水性、結晶性等を調節できる。 In the deprotection step, the deprotection reaction may be terminated halfway before all the protecting groups of the copolymer (B) are deprotected. In this case, a copolymer (A) having a unit based on the monomer (4), a unit based on the monomer (5), and a unit based on vinyl alcohol (a copolymer in which OH and OR 10 exist as Z). Polymer).
When the copolymer (B) contains a unit based on the monomer (6), the unit based on the monomer (4) and the vinyl monomer can be obtained by terminating the deprotection reaction in the middle. Copolymer (A) having a unit based on body (5), a unit based on vinyl alcohol, and a unit based on monomer (6) (a copolymer in which OH, OR 9 and OR 10 are present as Z) Is obtained.
As described above, the deprotection reaction is terminated halfway, the ratio of the unit based on the monomer (5) and the unit based on vinyl alcohol, or the unit based on the monomer (5) and the unit based on vinyl alcohol The hydrophilicity and crystallinity of the resulting copolymer (A) can be adjusted by adjusting the ratio of the monomer and the unit based on the monomer (6).
［分離膜の製造方法］
　本発明の分離膜の製造方法は特に限定されない。例えば、共重合体（Ａ）を溶融紡糸して得た中空糸を延伸する方法、共重合体（Ａ）を含む溶液に非溶媒を添加した際の相分離現象を利用する非溶媒誘起相分離法、共重合体（Ａ）を含む溶液からキャスト膜を作り、表面の溶媒のみ蒸発させた後に該キャスト膜を非溶媒中に浸漬するロブ‐スリラーヤン法、水蒸気吸収相分離法、共重合体（Ａ）を含む溶液を冷却した際に生じる相分離を利用する熱誘起相分離法等が挙げられる。塩阻止率に優れた分離膜を得られる点で、ロブ‐スリラーヤン法が好ましい。 [Method for producing separation membrane]
The method for producing the separation membrane of the present invention is not particularly limited. For example, a method of drawing a hollow fiber obtained by melt spinning a copolymer (A), a non-solvent induced phase separation utilizing a phase separation phenomenon when a non-solvent is added to a solution containing the copolymer (A) A Rob-Thrilleryan method, a water vapor absorption phase separation method, a copolymer in which a cast membrane is made from a solution containing the copolymer (A), only the solvent on the surface is evaporated and then the cast membrane is immersed in a non-solvent Examples include a thermally induced phase separation method using phase separation that occurs when the solution containing (A) is cooled. The Rob-Thrilleryan method is preferred in that a separation membrane having an excellent salt rejection can be obtained.
　すなわち、共重合体（Ａ）が水混和性の有機溶媒に溶解ないし分散されている液状組成物から該液状組成物の膜を形成し、該液状組成物の膜の表面から有機溶媒の一部を除去して部分乾燥膜を形成し、次いで、残余の有機溶媒を水に置換することにより前記液状組成物の膜を固体の膜に変換することが好ましい。
　この方法の特徴は、液状組成物の膜の表面から有機溶媒の一部を除去して部分乾燥膜を形成することにより膜表面に緻密な固体表面層を形成し、その後、膜中の残余の有機溶媒を水に置換することにより、部分乾燥膜の表面層以外の部分を多孔質固体層とする点にある。これにより、主として分離作用を担う表面層とその表面層を支える多孔質層の２層構造を有する非対称膜が得られる。
　具体的には、下記工程（１）～（４）を含む方法により本発明の分離膜を製造することが好ましい。
　工程（１）：共重合体（Ａ）と水混和性の有機溶媒から液状組成物を得る工程。
　工程（２）：基材表面に液状組成物を塗布して、基材表面上に液状組成物の膜を形成する工程。
　工程（３）：基材表面上の液状組成物膜の表面から有機溶媒の一部を除去し、有機溶媒除去前の液状組成物膜中の有機溶媒量（１００質量％）に対して３０～８０質量％の有機溶媒を含有する部分乾燥膜を形成する工程。
　工程（４）：部分乾燥膜を有する基材を水と接触させて、有機溶媒を水に置換し、水を含有する固体状の膜を形成する工程。 That is, a film of the liquid composition is formed from a liquid composition in which the copolymer (A) is dissolved or dispersed in a water-miscible organic solvent, and a part of the organic solvent is formed from the surface of the film of the liquid composition. It is preferable to convert the film of the liquid composition into a solid film by removing water to form a partially dried film and then replacing the remaining organic solvent with water.
The feature of this method is that a part of the organic solvent is removed from the surface of the liquid composition film to form a partially dry film, thereby forming a dense solid surface layer on the film surface, and then the remaining in the film. By replacing the organic solvent with water, the portion other than the surface layer of the partially dried membrane is made a porous solid layer. As a result, an asymmetric membrane having a two-layer structure of a surface layer mainly responsible for separation and a porous layer supporting the surface layer is obtained.
Specifically, it is preferable to produce the separation membrane of the present invention by a method including the following steps (1) to (4).
Step (1): A step of obtaining a liquid composition from the copolymer (A) and a water-miscible organic solvent.
Process (2): The process of apply | coating a liquid composition to the base-material surface, and forming the film | membrane of a liquid composition on a base-material surface.
Step (3): A part of the organic solvent is removed from the surface of the liquid composition film on the substrate surface, and the amount of the organic solvent in the liquid composition film before the organic solvent removal is 30 to 30% (100% by mass). A step of forming a partially dried film containing 80% by mass of an organic solvent.
Process (4): The process which makes the base material which has a partial dry film | membrane contact with water, replaces an organic solvent with water, and forms the solid-state film | membrane containing water.
　前記液状組成物における水混和性の有機溶媒は、共重合体（Ａ）を溶解するか、ナノスケール程度で分散することができるものであればよく、アルコール類、アミド類、エステル類およびカーボネート類からなる群より選ばれる少なくとも１種であることが好ましい。
　アルコール類としては、炭素数１～１０のアルコールが好ましく、例えば、メチルアルコール、エチルアルコール、ｎ－プロピルアルコール、イソプロピルアルコール、ｔ－ブタノール等のアルカノールが挙げられる。アミド類としては、炭素数３～７のジアルキルホルムアミド、アセトアミド、ピロリドン等が好ましく、例えば、ジメチルホルムアミド、Ｎ－メチルピロリドンが挙げられる。エステル類としては、エーテル性酸素原子を含んでもよい炭素数２～１０のエステルが好ましく、例えば、エチルアセテート、エチレングリコールモノメチルエーテルアセテートが挙げられる。カーボネート類としては、炭素数３～７のカーボネートが好ましく、例えば、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネートが挙げられる。
　水混和性の有機溶媒としては、水と置換が容易な点で炭素数４以下のアルカノールがより好ましく、メタノール、エタノール、およびこれらの混合物が特に好ましい。 The water-miscible organic solvent in the liquid composition is not limited as long as it can dissolve the copolymer (A) or can be dispersed at a nanoscale level. Alcohols, amides, esters and carbonates It is preferably at least one selected from the group consisting of
The alcohol is preferably an alcohol having 1 to 10 carbon atoms, and examples thereof include alkanols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and t-butanol. As the amide, dialkylformamide having 3 to 7 carbon atoms, acetamido, pyrrolidone and the like are preferable, and examples thereof include dimethylformamide and N-methylpyrrolidone. As the esters, esters having 2 to 10 carbon atoms which may contain an etheric oxygen atom are preferable, and examples thereof include ethyl acetate and ethylene glycol monomethyl ether acetate. As the carbonates, carbonates having 3 to 7 carbon atoms are preferable, and examples thereof include dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.
The water-miscible organic solvent is more preferably an alkanol having 4 or less carbon atoms in view of easy substitution with water, and methanol, ethanol, and a mixture thereof are particularly preferable.
　前記液状組成物には、膜の孔径を調節する目的で、共重合体（Ａ）を溶解しない溶媒（貧溶媒）を、共重合体（Ａ）が析出しない範囲で含んでいてもよい。貧溶媒としては、水、アルカン類、シクロアルカン類等が挙げられる。中でも、安価な点から、水が好ましい。
　さらに、液状組成物は親水性を向上させる目的で、多数の水酸基を有する化合物（糖類など）やカルボキシル基を有する化合物等の親水性化合物を含んでいてもよい。 The liquid composition may contain a solvent (poor solvent) that does not dissolve the copolymer (A) for the purpose of adjusting the pore size of the membrane as long as the copolymer (A) does not precipitate. Examples of the poor solvent include water, alkanes, and cycloalkanes. Of these, water is preferable because of its low cost.
Furthermore, the liquid composition may contain a hydrophilic compound such as a compound having a large number of hydroxyl groups (such as saccharides) or a compound having a carboxyl group for the purpose of improving hydrophilicity.
　液状組成物中における共重合（Ａ）の含有量は、５～５０質量％が好ましく、１０～４０質量％が特に好ましい。含有量が前記範囲であると、良好な液状組成物の膜が得られる。 The content of the copolymer (A) in the liquid composition is preferably 5 to 50% by mass, particularly preferably 10 to 40% by mass. When the content is in the above range, a film of a good liquid composition can be obtained.
　共重合体（Ａ）と水混和性の有機溶媒とを混合する手段としては、任意の撹拌手段が使用できる。例えば、ホモミキサー、ヘンシェルミキサー、バンバリーミキサー、加圧ニーダー等が挙げられる。 As the means for mixing the copolymer (A) and the water-miscible organic solvent, any stirring means can be used. Examples thereof include a homomixer, a Henschel mixer, a Banbury mixer, and a pressure kneader.
　液状組成物の膜を担持させるために通常基材を使用する。塗布等の手段で基材表面上に液状組成物を広げることにより基材表面上に液状組成物の膜を形成することができる。
　基材としては、ガラス、プラスチック等が挙げられる。
　基材表面に液状組成物を塗布する方法としては、スピンコーティング法、ワイプコート法、スプレーコート法、スキージーコート法、ディップコート法、ダイコート法、インクジェット法、フローコート法、ロールコート法、キャスト法、ラングミュア・ブロジェット法またはグラビアコート法等の公知の方法が挙げられる。中でも、膜厚均一性が高く、異物も少ない液状組成物の膜を得られる点で、キャスト法が好ましい。液状組成物の膜の厚さは、最終的に得られる膜の厚さが、上述の範囲になるようにすることが好ましい。 A substrate is usually used to support the film of the liquid composition. A film of the liquid composition can be formed on the substrate surface by spreading the liquid composition on the substrate surface by means such as coating.
Examples of the substrate include glass and plastic.
As a method of applying the liquid composition to the substrate surface, spin coating method, wipe coating method, spray coating method, squeegee coating method, dip coating method, die coating method, ink jet method, flow coating method, roll coating method, casting method And publicly known methods such as Langmuir-Blodgett method or gravure coating method. Among them, the casting method is preferable in that a film of a liquid composition having high film thickness uniformity and few foreign matters can be obtained. The film thickness of the liquid composition is preferably such that the final film thickness is in the above range.
　基材上の液状組成物の膜の表面から有機溶媒の一部を除去して部分乾燥膜を形成する際、有機溶媒を膜の露出表面（基材に接していない表面）から蒸発により除去する。これにより、液状組成物膜の露出表面に共重合体（Ａ）の固体状の層が形成される。この固体状の表面層は、非多孔性の層ないしは多孔性であっても緻密な層（孔の径が小さい層）である。固体状の表面層を形成することにより、塩阻止率の高い分離膜とすることができる。
　部分乾燥膜を得るために液状組成物の膜から有機溶媒を除去する方法としては特に限定されず、使用する有機溶媒に応じて、自然乾燥、風乾、加熱、減圧、減圧下の加熱等、適宜使用してよい。有機溶媒除去は、例えば、溶媒としてエタノールを使用した場合、加熱温度５０℃で６０秒間行う。
　部分乾燥膜を得るために液状組成物の膜から除去する有機溶媒の量は、除去前の有機溶媒量（１００質量％）に対して２０～７０質量％であることが好ましい。これにより、除去前の液状組成物の膜中の有機溶媒量（１００質量％）に対して３０～８０質量％の有機溶媒を含有する部分乾燥膜が得られる。 When a part of the organic solvent is removed from the surface of the liquid composition film on the substrate to form a partially dried film, the organic solvent is removed by evaporation from the exposed surface of the film (the surface not in contact with the substrate). . Thereby, a solid layer of the copolymer (A) is formed on the exposed surface of the liquid composition film. This solid surface layer is a non-porous layer or a dense layer (a layer having a small pore diameter) even if porous. By forming a solid surface layer, a separation membrane having a high salt rejection can be obtained.
The method for removing the organic solvent from the liquid composition film in order to obtain a partially dried film is not particularly limited, depending on the organic solvent used, such as natural drying, air drying, heating, reduced pressure, heating under reduced pressure, etc. May be used. The organic solvent is removed, for example, at a heating temperature of 50 ° C. for 60 seconds when ethanol is used as the solvent.
The amount of the organic solvent removed from the liquid composition film in order to obtain a partially dried film is preferably 20 to 70% by mass relative to the amount of the organic solvent before removal (100% by mass). As a result, a partially dried film containing 30 to 80% by mass of the organic solvent with respect to the amount of organic solvent (100% by mass) in the film of the liquid composition before removal is obtained.
　前記で得られた部分乾燥膜を、次いで、水と接触させて部分乾燥膜中の有機溶媒を水に置換し、膜全体を固体状の膜とする。水と接触させる方法は、部分乾燥膜を有する基材ごと、水中に浸漬することによって行うことができる。ここで、水は蒸留水、イオン交換水、超純水等のいずれであってもよい。水温は、０～３０℃が好ましい。接触時間は、部分乾燥膜の膜厚等により適宜調整でき、１～２４時間が好ましい。部分乾燥膜中の有機溶媒が水に完全に置換されたことは、得られた膜を、前記液状組成物に使用した有機溶媒とは異なる溶媒に浸漬し、浸漬後の溶媒をガスクロマトグラフィで分析することにより検出できる。
　有機溶媒を水に置換することにより固体の多孔質層が形成され、これにより、部分乾燥膜形成の際に形成された緻密な表面層とこの多孔質層が一体化した不均質膜が得られる。 The partially dried film obtained above is then brought into contact with water to replace the organic solvent in the partially dried film with water, and the entire film is made into a solid film. The method of making it contact with water can be performed by immersing the base material which has a partially dried film | membrane in water. Here, the water may be any of distilled water, ion exchange water, ultrapure water, and the like. The water temperature is preferably 0 to 30 ° C. The contact time can be appropriately adjusted depending on the thickness of the partially dried film, and is preferably 1 to 24 hours. The fact that the organic solvent in the partially dried film was completely replaced with water is that the obtained film was immersed in a solvent different from the organic solvent used in the liquid composition, and the solvent after the immersion was analyzed by gas chromatography. This can be detected.
By replacing the organic solvent with water, a solid porous layer is formed, thereby obtaining a heterogeneous film in which the porous layer is integrated with the dense surface layer formed during the formation of the partially dried film. .
　さらに、得られた固体状の膜（不均質膜）中の水は、必要によりその一部ないし全部を除去してもよい。水の除去は基材上に形成されている固体状の膜を基材とともに脱水処理を行ってもよく、基材から固体状の膜を剥離した後に脱水処理を行ってもよい。なお、水を含む固体状の膜は乾燥させると収縮することがあるため、膜を保存する際は水を含有した状態で保存することが好ましい。
　脱水方法としては、加熱、減圧、減圧下の加熱が挙げられ、簡便な点で加熱が好ましい。加熱温度は優れた塩阻止率を有する分離膜が得られる点で、３０～１００℃が好ましい。この脱水の工程としては、下記工程（５）が好ましい。
　工程（５）：前記水を含有する固体状膜を３０～１００℃の温度に加熱する工程。 Further, a part or all of the water in the obtained solid film (heterogeneous film) may be removed if necessary. For the removal of water, the solid film formed on the substrate may be dehydrated together with the substrate, or the solid film may be peeled off from the substrate and then dehydrated. In addition, since the solid film | membrane containing water may shrink | contract when dried, when preserve | saving a film | membrane, it is preferable to preserve | save in the state containing water.
Examples of the dehydration method include heating, reduced pressure, and heating under reduced pressure, and heating is preferable in terms of simplicity. The heating temperature is preferably 30 to 100 ° C. in that a separation membrane having an excellent salt rejection is obtained. As this dehydration step, the following step (5) is preferred.
Step (5): A step of heating the solid film containing water to a temperature of 30 to 100 ° C.
　得られる膜の孔の大きさを調節する目的で、固体状の膜を製造した後、それを熱処理してもよい。
　熱処理の温度は、膜の分解開始温度より低いことが好ましい。熱処理の方法としては、オーブン、ホットプレート等が挙げられる。 For the purpose of adjusting the pore size of the obtained membrane, it may be heat-treated after the solid membrane is produced.
The temperature of the heat treatment is preferably lower than the decomposition start temperature of the film. Examples of the heat treatment include an oven and a hot plate.
［実施例］
　以下、実施例を示して本発明を詳細に説明する。ただし、本発明は以下の記載によっては限定されない。 [Example]
Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following description.
［測定方法］
　実施例で使用した各測定方法は以下のとおりである。
（質量平均分子量（Ｍｗ）、数平均分子量（Ｍｎ）、分子量分布（Ｍｗ／Ｍｎ））
　各例で得られた共重合体の質量平均分子量（Ｍｗ）、数平均分子量（Ｍｎ）および分子量分布（Ｍｗ／Ｍｎ）は、東ソー社製の高速ＧＰＣ装置「ＨＬＣ－８２２０ＧＰＣ」を使用し、ポリスチレンゲル換算のゲル濾過クロマトグラフィー（ＧＰＣ）で測定した。溶離液はテトラヒドロフランを用いた。 [Measuring method]
Each measuring method used in the examples is as follows.
(Mass average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn))
The mass average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the copolymer obtained in each example were measured using a high-speed GPC device “HLC-8220GPC” manufactured by Tosoh Corporation. It measured by the gel filtration chromatography (GPC) of gel conversion. Tetrahydrofuran was used as the eluent.
（共重合体の構造および組成）
　各例で得られた共重合体の構造および組成については、１Ｈ　ＮＭＲおよび１９Ｆ　ＮＭＲスペクトルの測定から同定しおよび算出した。 (Copolymer structure and composition)
The structure and composition of the copolymer obtained in each example were identified and calculated from measurement of 1 H NMR and 19 F NMR spectra.
（共重合体の熱特性）
　各例で得られた共重合体のガラス転移点（Ｔｇ）は、ティー・エイ・インスツルメント社製の示差走査熱量計「Ｑ１００」を用いて測定し、１０％質量減量温度（Ｔｄ１０）は、ブルカー・エイエックスエス社製の示差熱・熱質量同時測定装置「ＴＧ－ＤＴＡ２０００ＳＡ」を用いて測定した。 (Thermal properties of the copolymer)
The glass transition point (Tg) of the copolymer obtained in each example was measured using a differential scanning calorimeter “Q100” manufactured by TA Instruments, and the 10% mass loss temperature (Td10) was The measurement was performed using a simultaneous differential heat / thermal mass measurement apparatus “TG-DTA2000SA” manufactured by Bruker AXS.
（交互配列率の計算方法）
　モノマー固有の数値であるＱ値およびｅ値から計算される共重合反応性比に基づいて、モンテカルロ法によりシーケンス解析を行った。 (Calculation method of alternating sequence ratio)
Sequence analysis was performed by the Monte Carlo method based on the copolymerization reactivity ratio calculated from the Q value and e value, which are specific values of the monomer.
（水接触角）
　協和界面科学社製の接触角計「ＤＭ－７００」を用い、２５℃の条件下、液滴法で行った。共重合体フィルムの上に、約１μＬの純水を滴下して水接触角を測定した。 (Water contact angle)
Using a contact angle meter “DM-700” manufactured by Kyowa Interface Science Co., Ltd., the droplet method was used at 25 ° C. About 1 μL of pure water was dropped on the copolymer film, and the water contact angle was measured.
（引張試験）
　ダンベル形状の長さ６３ｍｍ、幅３ｍｍの引張試験用サンプルを作成し、エー・アンド・デイ社製のテンシロン万能試験機「ＲＴＣ－１２１０」を用いて、温度２５℃、湿度５０％の条件下、標線間距離１０ｍｍ、試験速度１０ｍｍ／分で引張試験を行い、破断点伸度、最大点応力を測定した。 (Tensile test)
A dumbbell-shaped sample for tensile test with a length of 63 mm and a width of 3 mm was prepared, and a Tensilon universal testing machine “RTC-1210” manufactured by A & D Corporation was used. A tensile test was performed at a distance between marked lines of 10 mm and a test speed of 10 mm / min, and the elongation at break and the maximum point stress were measured.
（耐酸化剤特性）
　ダンベル形状の共重合体フィルムを、次亜塩素酸ソーダ水溶液（有効塩素濃度１，０００ｐｐｍ、ｐＨ１０）に、室温下４週間浸漬した後、水で洗浄し、乾燥した後、上記と同様の方法で、引張試験を行った。 (Oxidant resistance properties)
The dumbbell-shaped copolymer film was immersed in an aqueous sodium hypochlorite solution (effective chlorine concentration 1,000 ppm, pH 10) for 4 weeks at room temperature, washed with water, dried, and then the same method as above. A tensile test was performed.
（表面ゼータ電位）
　大塚電子社製のゼータ電位・粒径測定システム「ＥＬＳＺ－１０００ＺＳ」を用い、２５℃で測定した。 (Surface zeta potential)
The measurement was carried out at 25 ° C. using a zeta potential / particle size measurement system “ELSZ-1000ZS” manufactured by Otsuka Electronics.
（脱塩試験）
　０．１５質量％塩化ナトリウム水溶液を試験液とし、日東電工社製のフロー式平膜テストセル「メンブレンマスターＣ７０－Ｆ」を用いて行った。試験液の塩分濃度が一定になるように試験液をポンプで循環させ、液温２５℃において、圧力０．４５ＭＰａＧ下で、クロスフロー方式により濾過試験を行った。得られた濾液中の塩化ナトリウム濃度を求め、下式により、塩阻止率を求めた。
　［（０．１５－濾液中の塩化ナトリウム濃度（質量％））／０．１５］×１００（％）
　なお、濾液中の塩化ナトリウム濃度は、東亜ディーケーケー社製の電気伝導度計「ＣＭ－３０Ｒ」を用い、２５℃で測定した電気伝導度から、検量線から読み取った。
　また、得られた濾液の質量を測定し、該質量を濾過に必要とした時間および濾過面積で割ることで、濾過流束（Ｌ／ｍ２・ｄａｙ）を計算した。 (Desalination test)
A 0.15 mass% sodium chloride aqueous solution was used as a test solution, and a flow type flat membrane test cell “Membrane Master C70-F” manufactured by Nitto Denko Corporation was used. The test solution was circulated with a pump so that the salt concentration of the test solution was constant, and a filtration test was performed by a cross flow method at a liquid temperature of 25 ° C. and a pressure of 0.45 MPaG. The sodium chloride concentration in the obtained filtrate was determined, and the salt rejection was determined according to the following formula.
[(0.15-concentration of sodium chloride in filtrate (% by mass)) / 0.15] × 100 (%)
The sodium chloride concentration in the filtrate was read from a calibration curve from the electric conductivity measured at 25 ° C. using an electric conductivity meter “CM-30R” manufactured by Toa DKK Corporation.
Further, the mass of the obtained filtrate was measured, and the filtration flux (L / m 2 · day) was calculated by dividing the mass by the time required for filtration and the filtration area.
［合成例１］
　内容積１Ｌのステンレス鋼製攪拌機付きオートクレーブ（耐圧３．４ＭＰａ）に、イオン交換水の４９０．５ｇ、単量体（５）であるｔ－ブチルビニルエーテル（以下、「ＴＢＶＥ」という。）の１２５．０ｇ、乳化剤であるペルフルオロオクタン酸アンモニウム（以下、「ＡＰＦＯ」という。）の２．５ｇ、リン酸水素２ナトリウム１２水和物の２８．３ｇおよび過硫酸アンモニウム（以下、「ＡＰＳ」という。）の１０．０ｇを仕込んだ。オートクレーブ内を、窒素ガスで０．５ＭＰａＧまで昇圧後、０．０５ＭＰａＧまでパージする操作を１０回繰返し、系内の酸素を除去し、内温を３０℃に制御した。
　次に、単量体（４）であるテトラフルオロエチレン（以下、「ＴＦＥ」という。）の８１．３ｇをオートクレーブ中に導入した。この時点での圧力は１．６６ＭＰａＧであった。その後、１０質量％濃度の亜硫酸水素ナトリウム水溶液の２．５ｇを添加し、重合を開始した。
　重合開始後も、圧力が１．６６ＭＰａＧを維持するように、ＴＦＥの導入を継続した。１０質量％濃度の亜硫酸水素ナトリウム水溶液を、１５分に１回の頻度で２．５ｇずつ間欠的に導入した。６時間反応を続行し、ＴＦＥを全体で１０７ｇ導入し、１０質量％濃度の亜硫酸水素ナトリウム水溶液を全体で６０ｇ導入したところで、未反応ガスをパージして反応を停止させた。得られた重合溶液をメタノール中に投入し、生成した共重合体（以下、「共重合体Ｂ１」という。）を析出させた後、真空乾燥を行った。共重合体（Ｂ１）の収量は５１．０ｇ、ＴＢＶＥの反応率は２０％であった。
　得られた共重合体（Ｂ１）のＭｗは２７８，０００、Ｍｎは１３４,０００、Ｍｗ／Ｍｎは２．１であった。１Ｈ　ＮＭＲスペクトルおよび１９Ｆ　ＮＭＲスペクトルから、共重合組成比はＴＦＥ／ＴＢＶＥ＝４９／５１（モル％）であった。また、両単量体の共重合反応性比からの計算で実質的に交互配列（交互配列率９５%以上）を有していることを確認した。 [Synthesis Example 1]
Into an autoclave with a stainless steel stirrer with an internal volume of 1 L (pressure resistance: 3.4 MPa), 490.5 g of ion-exchanged water and t-butyl vinyl ether (hereinafter referred to as “TBVE”) which is monomer (5), 125. 0 g, 2.5 g of ammonium perfluorooctanoate (hereinafter referred to as “APFO”) as an emulsifier, 28.3 g of disodium hydrogenphosphate dodecahydrate and 10 of ammonium persulfate (hereinafter referred to as “APS”). 0.0 g was charged. The operation of increasing the pressure in the autoclave to 0.5 MPaG with nitrogen gas and then purging to 0.05 MPaG was repeated 10 times to remove oxygen in the system and control the internal temperature to 30 ° C.
Next, 81.3 g of tetrafluoroethylene (hereinafter referred to as “TFE”) as the monomer (4) was introduced into the autoclave. The pressure at this time was 1.66 MPaG. Thereafter, 2.5 g of a 10% strength by weight aqueous sodium hydrogen sulfite solution was added to initiate polymerization.
Even after the start of polymerization, the introduction of TFE was continued so that the pressure was maintained at 1.66 MPaG. An aqueous solution of sodium bisulfite having a concentration of 10% by mass was intermittently introduced at a rate of 2.5 g once every 15 minutes. The reaction was continued for 6 hours. A total of 107 g of TFE was introduced and 60 g of a 10% strength by weight aqueous sodium hydrogen sulfite solution was introduced, and then the reaction was stopped by purging the unreacted gas. The obtained polymerization solution was put into methanol to precipitate a produced copolymer (hereinafter referred to as “copolymer B1”), followed by vacuum drying. The yield of the copolymer (B1) was 51.0 g, and the reaction rate of TBVE was 20%.
Mw of the obtained copolymer (B1) was 278,000, Mn was 134,000, and Mw / Mn was 2.1. From the 1 H NMR spectrum and the 19 F NMR spectrum, the copolymer composition ratio was TFE / TBVE = 49/51 (mol%). In addition, it was confirmed by the calculation from the copolymerization reactivity ratio of both monomers that there was substantially an alternating arrangement (alternating arrangement ratio of 95% or more).
　５００ｍＬフラスコに、共重合体（Ｂ１）の４９ｇ、３６質量％濃塩酸の４９ｇ、エタノールの３１５ｇを入れ、内温７８℃で加熱攪拌し、置換反応を行った。反応を８時間続行した後、反応液を水中に滴下し、共重合体を析出させ、水で洗浄した後、９０℃で真空乾燥を行い、共重合体（以下、「共重合体（Ａ１）」という。）の３３ｇを得た。本工程において着色は見られなかった。
　共重合体（Ｂ１）および共重合体（Ａ１）について、１Ｈ　ＮＭＲスペクトルおよび１９Ｆ　ＮＭＲを測定した結果から、共重合体（Ａ１）においては、加水分解により９９％以上のＲ１（ｔ－ブチル基）が水素に置換されて水酸基が生成したことが確認され（Ｒ１が水素で置換された繰り返し単位を以下、「ＶＡｌ」という。）、共重合組成比はＴＦＥ／ＶＡｌ＝４７／５３（モル％）、Ｍｗは２６１，０００、Ｍｎは１１５，０００、Ｍｗ／Ｍｎ＝２．３であった。また、Ｔｇは８９℃、Ｔｄ１０は４０７℃であった。 A 500 mL flask was charged with 49 g of copolymer (B1), 49 g of 36 mass% concentrated hydrochloric acid, and 315 g of ethanol, and the mixture was heated and stirred at an internal temperature of 78 ° C. to carry out a substitution reaction. After the reaction was continued for 8 hours, the reaction solution was dropped into water to precipitate a copolymer, washed with water, and then vacuum dried at 90 ° C. to obtain a copolymer (hereinafter referred to as “copolymer (A1)”). ”) Was obtained. No coloring was seen in this step.
From the results of measuring 1 H NMR spectrum and 19 F NMR for the copolymer (B1) and the copolymer (A1), 99% or more of R 1 (t- (Butyl group) was replaced by hydrogen to form a hydroxyl group (the repeating unit in which R 1 is replaced by hydrogen is hereinafter referred to as “VAl”), and the copolymer composition ratio was TFE / VA1 = 47/53. (Mole%), Mw was 261,000, Mn was 115,000, and Mw / Mn = 2.3. Moreover, Tg was 89 degreeC and Td10 was 407 degreeC.
［合成例２］
　内容積１Ｌのステンレス鋼製攪拌機付きオートクレーブに、酢酸メチルの３５４ｇ、単量体（５）である酢酸ビニル（以下、「ＶＡｃ」という。）の６３ｇ、およびｔ－ブチルパーオキシピバレート（以下、「ＰＢＰＶ」という。）の５０％１，１，１，２，２，３，３，４，４，５，５，６，６－トリデカフルオロヘキサン溶液の２．３ｇを仕込み、液体窒素で凍結脱気を行い、系内の酸素を除去した。次いで、ＴＦＥの１７９ｇをオートクレーブ中に導入し、５５℃まで加熱した。その後、１０分間反応を続行した後、オートクレーブを水冷し、未反応ガスをパージして反応を停止させた。得られた重合溶液をメタノール中に投入し、生成した共重合体を析出させた後、真空乾燥を行い、共重合体（以下、「共重合体（Ｂ２）」という。）の固体を得た。共重合体（Ｂ２）の収量は１１０ｇ、酢酸ビニルの反応率は４５％であった。
　得られた共重合体（Ｂ２）のＭｗは２７８，０００、Ｍｎは８４，０００、Ｍｗ／Ｍｎは３．３だった。１Ｈ　ＮＭＲスペクトルおよび１９Ｆ　ＮＭＲスペクトルから、共重合組成比はＴＦＥ／ＶＡｃ＝５０／５０（モル％）であった。また、両単量体の共重合反応性比からの計算で、共重合体（Ｂ２）の交互配列率は８０～８５％であった。 [Synthesis Example 2]
In an autoclave with a stirrer made of stainless steel having an internal volume of 1 L, 354 g of methyl acetate, 63 g of vinyl acetate (hereinafter referred to as “VAc”) as monomer (5), and t-butyl peroxypivalate (hereinafter referred to as “V-Ac”). 2.3% of 50% 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorohexane solution of “PBPV”) Freeze deaeration was performed to remove oxygen in the system. Next, 179 g of TFE was introduced into the autoclave and heated to 55 ° C. Thereafter, the reaction was continued for 10 minutes, and then the autoclave was cooled with water and purged with unreacted gas to stop the reaction. The obtained polymerization solution was put into methanol and the produced copolymer was precipitated, followed by vacuum drying to obtain a solid of a copolymer (hereinafter referred to as “copolymer (B2)”). . The yield of copolymer (B2) was 110 g, and the reaction rate of vinyl acetate was 45%.
Mw of the obtained copolymer (B2) was 278,000, Mn was 84,000, and Mw / Mn was 3.3. From the 1 H NMR spectrum and the 19 F NMR spectrum, the copolymer composition ratio was TFE / VAc = 50/50 (mol%). Further, the alternating arrangement ratio of the copolymer (B2) was 80 to 85% as calculated from the copolymerization reactivity ratio of both monomers.
　１００ｍＬフラスコに共重合体（Ｂ２）の４．１ｇ、３６質量％濃塩酸の４．０ｇ、エタノールの５２ｇを入れ、内温７８℃で加熱攪拌し、脱保護反応を行った。反応を３２時間続行した後、反応液を水中に滴下し、共重合体を析出させ、水で洗浄した後、９０℃で真空乾燥を行い、共重合体（以下「共重合体（Ａ２）」という。）の２．７ｇを得た。
　共重合体（Ｂ２）および共重合体（Ａ２）について、１Ｈ　ＮＭＲスペクトルおよび１９Ｆ　ＮＭＲスペクトルから、加水分解により９９％以上のアセチル基が水素に置換されて水酸基が生成したことが確認できた。共重合体（Ａ２）においては、共重合組成比はＴＦＥ／ＶＡｌ＝５０／５０（モル％）、Ｍｗは２７５，０００、Ｍｎは７４，０００、Ｍｗ／Ｍｎ＝３．７であった。また、Ｔｇは８５℃、Ｔｄ１０は３７９℃であった。 A 100 mL flask was charged with 4.1 g of the copolymer (B2), 4.0 g of 36 mass% concentrated hydrochloric acid, and 52 g of ethanol, and the mixture was heated and stirred at an internal temperature of 78 ° C. for deprotection reaction. After the reaction was continued for 32 hours, the reaction solution was dropped into water to precipitate a copolymer, washed with water, and then vacuum dried at 90 ° C. to obtain a copolymer (hereinafter referred to as “copolymer (A2)”). 2.7 g of the product was obtained.
As for copolymer (B2) and copolymer (A2), it was confirmed from the 1 H NMR spectrum and 19 F NMR spectrum that 99% or more of the acetyl groups were replaced with hydrogen by hydrolysis to generate hydroxyl groups. . In the copolymer (A2), the copolymer composition ratio was TFE / VA1 = 50/50 (mol%), Mw was 275,000, Mn was 74,000, and Mw / Mn = 3.7. Moreover, Tg was 85 degreeC and Td10 was 379 degreeC.
［実施例１］
　合成例１で得た共重合体（Ａ１）をエタノールに溶解し、１０質量％の溶液を得た。この溶液をＰＴＦＥシート上に塗布後、エタノールを完全に蒸発させ、厚さ５０μｍのキャストフィルム（共重合体フィルム）を作成した。該フィルムの水接触角測定、引張試験、耐酸化剤特性測定を行った。共重合体フィルムは次亜塩素酸ソーダ浸漬後も、伸度、強度ともに保持し、フィルムの靭性を失っていなかった。
　次に、共重合体（Ａ１）をエタノールに溶解し、２０質量％の溶液（液状組成物）を得た。該溶液をガラス基板（旭硝子社製、縦１００ｍｍ×横１００ｍｍ×厚さ１ｍｍ）に塗布して液状組成物の膜を形成し、次に該液状組成物の膜を有するガラス基板を５０℃で６０秒間加熱して、含まれる溶媒量が加熱前の溶媒量（１００質量％）の４５質量％にした部分乾燥膜を有するガラス基板を得た。次いで、部分乾燥膜をガラス基板ごと水中に浸漬し、エタノールを水に置換し、水を含有する不均質膜を得た。ガラス基板から水を含有する不均質膜を剥離して、不均質膜の表面ゼータ電位測定、脱塩試験を行った。塩阻止率は５％であり、脱塩性能に優れることを確認した。評価結果を表１に示す。なお、水を含有する不均質膜から水を除去して得た乾燥膜の厚さをマイクロメータで測定したところ、７０μｍであった。 [Example 1]
The copolymer (A1) obtained in Synthesis Example 1 was dissolved in ethanol to obtain a 10% by mass solution. After applying this solution on a PTFE sheet, ethanol was completely evaporated to prepare a cast film (copolymer film) having a thickness of 50 μm. The film was subjected to water contact angle measurement, tensile test, and oxidation resistance property measurement. The copolymer film maintained both elongation and strength even after immersion in sodium hypochlorite, and did not lose the toughness of the film.
Next, the copolymer (A1) was dissolved in ethanol to obtain a 20% by mass solution (liquid composition). The solution is applied to a glass substrate (manufactured by Asahi Glass Co., Ltd., length 100 mm × width 100 mm × thickness 1 mm) to form a liquid composition film, and then the glass substrate having the liquid composition film is formed at 60 ° C. at 60 ° C. By heating for 2 seconds, a glass substrate having a partially dried film whose amount of solvent contained was 45% by mass of the amount of solvent before heating (100% by mass) was obtained. Subsequently, the partially dried film was immersed in water together with the glass substrate, ethanol was replaced with water, and a heterogeneous film containing water was obtained. The heterogeneous film containing water was peeled from the glass substrate, and the surface zeta potential of the heterogeneous film was measured and a desalting test was performed. The salt rejection was 5%, and it was confirmed that the salt rejection was excellent. The evaluation results are shown in Table 1. In addition, when the thickness of the dry film | membrane obtained by removing water from the heterogeneous film | membrane containing water was measured with the micrometer, it was 70 micrometers.
［実施例２］
　合成例２で得た共重合体（Ａ２）を用い、実施例１と同様に、厚さ５０μｍの共重合体フィルムを作成し、水接触角測定、引張試験、耐酸化剤特性測定を行った。共重合体フィルムは次亜塩素酸ソーダ浸漬後に、伸度は低下したが、強度は保持していた。さらに、実施例１と同様に不均質膜を製造し、その物性を測定した。評価結果を表１に示す。実施例１と同様に水を除去して得た乾燥膜の厚さをマイクロメータで測定したところ、７５μｍであった。 [Example 2]
Using the copolymer (A2) obtained in Synthesis Example 2, a copolymer film having a thickness of 50 μm was prepared in the same manner as in Example 1, and a water contact angle measurement, a tensile test, and an oxidation resistance property measurement were performed. . The copolymer film decreased in elongation after immersion in sodium hypochlorite, but maintained its strength. Further, a heterogeneous film was produced in the same manner as in Example 1, and its physical properties were measured. The evaluation results are shown in Table 1. It was 75 micrometers when the thickness of the dry film obtained by removing water similarly to Example 1 was measured with the micrometer.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
［比較例１］
　ポリフッ化ビニリデン（クレハ社製、商品名：ＫＦ－１１００）を、Ｎ，Ｎ－ジメチルアセトアミドに溶解し、１８質量％の溶液を得た。該溶液をガラス基板に塗布して塗膜を得て、次に塗膜を有するガラス基板（旭硝子社製、縦１００ｍｍ×横１００ｍｍ×厚さ１ｍｍ）を８０℃で６０秒間加熱して、含まれる溶媒量が加熱前の溶媒量（１００質量％）の４０質量％にした部分乾燥膜を有するガラス基板を得た。ガラス基板ごと水中に浸漬し、溶媒を水に置換し、水を含有する不均質膜を得た。ガラス基板から水を含有する不均質膜を剥離して、水接触角の測定と、脱塩試験を行った。水接触角は１１０度であり、水は透過しなかった。実施例１と同様に水を除去して得た乾燥膜の厚さをマイクロメータで測定したところ、６５μｍであった。 [Comparative Example 1]
Polyvinylidene fluoride (manufactured by Kureha, trade name: KF-1100) was dissolved in N, N-dimethylacetamide to obtain an 18% by mass solution. The solution is applied to a glass substrate to obtain a coating film, and then a glass substrate having a coating film (Asahi Glass Co., Ltd., length 100 mm × width 100 mm × thickness 1 mm) is heated at 80 ° C. for 60 seconds and contained. A glass substrate having a partially dried film whose solvent amount was 40% by mass of the solvent amount before heating (100% by mass) was obtained. The glass substrate was immersed in water, the solvent was replaced with water, and a heterogeneous film containing water was obtained. The heterogeneous film containing water was peeled from the glass substrate, and the water contact angle was measured and a desalting test was performed. The water contact angle was 110 degrees, and water did not permeate. When the thickness of the dry film obtained by removing water was measured with a micrometer in the same manner as in Example 1, it was 65 μm.
　本発明の分離膜は、水処理用、電池セパレータ、食品製造用、医療用等の膜等に好適に応用できる。
　なお、２０１２年１１月３０日に出願された日本特許出願２０１２－２６２３１４号の明細書、特許請求の範囲および要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。 The separation membrane of the present invention can be suitably applied to membranes for water treatment, battery separators, food production, medical use and the like.
The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2012-262314 filed on November 30, 2012 are incorporated herein as the disclosure of the specification of the present invention. It is.

Claims (15)

  1. 　下式（１）で表される単位と下式（２）で表される単位とを含み、質量平均分子量が５０，０００～１，０００，０００である共重合体からなり、０．１５質量％塩化ナトリウム水溶液を用いた、２５℃および０．４５ＭＰａＧにおけるクロスフロー方式での塩阻止率が少なくとも３％であることを特徴とする分離膜。
    Figure JPOXMLDOC01-appb-C000001
     　式（１）中、ＸおよびＹは、それぞれ独立にＨ、Ｆ、ＣＦ３またはＣｌである。
    　式（２）中、ＺはＯＲ１、ＮＨＲ２、ＣＯＯＲ３またはＳＯ３Ｒ４である。Ｒは単結合、エーテル性酸素原子を含んでもよい２価の連結基、または環構造を含んでもよい２価の連結基である。Ｒ１～Ｒ４は、それぞれ独立にＨまたは１価の有機基である。
    　ただし、前記共重合体に含まれる式（２）で表される単位のうち、Ｒ１～Ｒ４がＨである単位の割合は５０モル％以上である。     A copolymer comprising a unit represented by the following formula (1) and a unit represented by the following formula (2) and having a mass average molecular weight of 50,000 to 1,000,000, and 0.15 mass A separation membrane characterized by having a salt rejection of at least 3% in a cross-flow method at 25 ° C. and 0.45 MPaG using a% sodium chloride aqueous solution.
    Figure JPOXMLDOC01-appb-C000001
     In formula (1), X and Y are each independently H, F, CF 3 or Cl.
    In the formula (2), Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 . R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure. R 1 to R 4 are each independently H or a monovalent organic group.
    However, the proportion of units in which R 1 to R 4 are H among the units represented by the formula (2) contained in the copolymer is 50 mol% or more.
  2. 　前記共重合体において、式（１）で表される単位と式（２）で表される単位のモル比が、４０／６０～６０／４０である、請求項１に記載の分離膜。 2. The separation membrane according to claim 1, wherein in the copolymer, the molar ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is 40/60 to 60/40.
  3. 　前記共重合体において、式（１）で表される単位と式（２）で表される単位との交互配列率が９５％以上である、請求項１または２に記載の分離膜。 The separation membrane according to claim 1 or 2, wherein in the copolymer, the alternating arrangement ratio of the unit represented by the formula (1) and the unit represented by the formula (2) is 95% or more.
  4. 　前記共重合体において、ＸがＦであり、ＹがＦまたはＣｌである、請求項１～３のいずれか一項に記載の分離膜。 The separation membrane according to any one of claims 1 to 3, wherein, in the copolymer, X is F and Y is F or Cl.
  5. 　前記共重合体において、ＺがＯＲ１である、請求項１～４のいずれか一項に記載の分離膜。 The separation membrane according to any one of claims 1 to 4, wherein Z is OR 1 in the copolymer.
  6. 　前記共重合体において、Ｒが単結合、Ｏ（ＣＨ２）ｎまたは（ＯＣＨ２ＣＨ２）ｍである（ただしｎは２～４の整数であり、ｍは１～４の整数である。）、請求項１～５のいずれか一項に記載の分離膜。 In the copolymer, R is a single bond, O (CH 2 ) n or (OCH 2 CH 2 ) m (where n is an integer of 2 to 4 and m is an integer of 1 to 4). The separation membrane according to any one of claims 1 to 5.
  7. 　分離膜が、浄水処理用または海水淡水化処理用の膜である、請求項１～６のいずれか一項に記載の分離膜。 The separation membrane according to any one of claims 1 to 6, wherein the separation membrane is a membrane for water purification treatment or seawater desalination treatment.
  8. 　請求項１～６のいずれか一項に記載の分離膜を製造する方法であって、
    　前記共重合体が水混和性の有機溶媒に溶解ないし分散されている液状組成物から該液状組成物の膜を形成し、該液状組成物の膜の表面から有機溶媒の一部を除去して部分乾燥膜を形成し、次いで、残余の有機溶媒を水に置換することにより前記液状組成物の膜を固体の膜に変換することを特徴とする分離膜の製造方法。     A method for producing the separation membrane according to any one of claims 1 to 6,
    A film of the liquid composition is formed from a liquid composition in which the copolymer is dissolved or dispersed in a water-miscible organic solvent, and a part of the organic solvent is removed from the surface of the liquid composition film. A method for producing a separation membrane, wherein a membrane of the liquid composition is converted into a solid membrane by forming a partially dried membrane and then substituting the remaining organic solvent with water.
  9. 　前記水混和性の有機溶媒が、アルコール類、アミド類、エステル類およびカーボネート類からなる群より選ばれる少なくとも１種の有機溶媒である、請求項８に記載の分離膜の製造方法。 The method for producing a separation membrane according to claim 8, wherein the water-miscible organic solvent is at least one organic solvent selected from the group consisting of alcohols, amides, esters and carbonates.
  10. 　前記水混和性の有機溶媒が炭素数４以下のアルカノールである、請求項８または９に記載の分離膜の製造方法。 The method for producing a separation membrane according to claim 8 or 9, wherein the water-miscible organic solvent is an alkanol having 4 or less carbon atoms.
  11. 　下記工程（１）～（４）を含む、請求項８～１０のいずれか一項に記載の分離膜の製造方法。
    　工程（１）：前記共重合体と前記水混和性の有機溶媒から前記液状組成物を得る工程。
    　工程（２）：基材表面に前記液状組成物を塗布して、基材表面上に液状組成物の膜を形成する工程。
    　工程（３）：前記基材表面上の液状組成物の膜の表面から前記有機溶媒の一部を除去し、有機溶媒除去前の液状組成物膜中の有機溶媒量（１００質量％）に対して３０～８０質量％の有機溶媒を含有する部分乾燥膜を形成する工程。
    　工程（４）：前記部分乾燥膜を有する基材を水と接触させて、前記有機溶媒を水に置換し、水を含有する固体状の膜を形成する工程。     The method for producing a separation membrane according to any one of claims 8 to 10, comprising the following steps (1) to (4).
    Step (1): A step of obtaining the liquid composition from the copolymer and the water-miscible organic solvent.
    Process (2): The process of apply | coating the said liquid composition on the base-material surface, and forming the film | membrane of a liquid composition on a base-material surface.
    Step (3): A part of the organic solvent is removed from the surface of the liquid composition film on the substrate surface, and the amount of the organic solvent (100% by mass) in the liquid composition film before removing the organic solvent. Forming a partially dried film containing 30 to 80% by mass of an organic solvent.
    Step (4): A step of bringing the substrate having the partially dried film into contact with water, replacing the organic solvent with water, and forming a solid film containing water.
  12. 　さらに下記工程（５）を含む、請求項１１に記載の分離膜の製造方法。
    　工程（５）：前記水を含有する固体状膜を３０～１００℃の温度に加熱する工程。     Furthermore, the manufacturing method of the separation membrane of Claim 11 including the following process (5).
    Step (5): A step of heating the solid film containing water to a temperature of 30 to 100 ° C.
  13. 　下式（１）で表される単位と下式（２）で表される単位とを含み、質量平均分子量が５０，０００～１，０００，０００である共重合体が、水混和性の有機溶媒に溶解ないし分散されている液状組成物であることを特徴とする分離膜製造用の液状組成物。
    Figure JPOXMLDOC01-appb-C000002
     　式（１）中、ＸおよびＹは、それぞれ独立にＨ、Ｆ、ＣＦ３またはＣｌである。
    　式（２）中、ＺはＯＲ１、ＮＨＲ２、ＣＯＯＲ３またはＳＯ３Ｒ４である。Ｒは単結合、エーテル性酸素原子を含んでもよい２価の連結基、または環構造を含んでもよい２価の連結基である。Ｒ１～Ｒ４は、それぞれ独立にＨまたは１価の有機基である。
    　ただし、前記共重合体に含まれる式（２）で表される単位のうち、Ｒ１～Ｒ４がＨである単位の割合は５０モル％以上である。     A copolymer having a unit represented by the following formula (1) and a unit represented by the following formula (2) and having a mass average molecular weight of 50,000 to 1,000,000 is a water-miscible organic A liquid composition for producing a separation membrane, which is a liquid composition dissolved or dispersed in a solvent.
    Figure JPOXMLDOC01-appb-C000002
     In formula (1), X and Y are each independently H, F, CF 3 or Cl.
    In the formula (2), Z represents OR 1 , NHR 2 , COOR 3 or SO 3 R 4 . R is a single bond, a divalent linking group that may contain an etheric oxygen atom, or a divalent linking group that may contain a ring structure. R 1 to R 4 are each independently H or a monovalent organic group.
    However, the proportion of units in which R 1 to R 4 are H among the units represented by the formula (2) contained in the copolymer is 50 mol% or more.
  14. 　前記水混和性の有機溶媒が、アルコール類、アミド類、エステル類およびカーボネート類からなる群より選ばれる少なくとも１種の有機溶媒である、請求項１３に記載の分離膜製造用の液状組成物。 The liquid composition for producing a separation membrane according to claim 13, wherein the water-miscible organic solvent is at least one organic solvent selected from the group consisting of alcohols, amides, esters and carbonates.
  15. 　前記水混和性の有機溶媒が炭素数４以下のアルカノールである、請求項１３または１４に記載の分離膜製造用の液状組成物。 The liquid composition for producing a separation membrane according to claim 13 or 14, wherein the water-miscible organic solvent is an alkanol having 4 or less carbon atoms.
PCT/JP2013/082184 2012-11-30 2013-11-29 Separation membrane comprising fluorine-containing copolymer WO2014084356A1 (en)

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