WO2023276867A1 - Coating starting material for secondary battery separator, coating material for secondary battery separator, secondary battery separator, method for producing secondary battery separator, and secondary battery - Google Patents

Coating starting material for secondary battery separator, coating material for secondary battery separator, secondary battery separator, method for producing secondary battery separator, and secondary battery Download PDF

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Publication number
WO2023276867A1
WO2023276867A1 PCT/JP2022/025239 JP2022025239W WO2023276867A1 WO 2023276867 A1 WO2023276867 A1 WO 2023276867A1 JP 2022025239 W JP2022025239 W JP 2022025239W WO 2023276867 A1 WO2023276867 A1 WO 2023276867A1
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Prior art keywords
water
secondary battery
battery separator
mass
reactive functional
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PCT/JP2022/025239
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French (fr)
Japanese (ja)
Inventor
嘉彦 富田
維 李
剛 松本
靖之 香川
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三井化学株式会社
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Application filed by 三井化学株式会社 filed Critical 三井化学株式会社
Priority to KR1020237036846A priority Critical patent/KR20230162050A/en
Priority to JP2023531892A priority patent/JPWO2023276867A1/ja
Priority to CN202280029862.XA priority patent/CN117242634A/en
Publication of WO2023276867A1 publication Critical patent/WO2023276867A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/42—Acrylic resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H01M50/434—Ceramics
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a coating material raw material for a secondary battery separator, a coating material for a secondary battery separator, a secondary battery separator, a method for manufacturing a secondary battery separator, and a secondary battery.
  • a secondary battery is equipped with a separator that separates the positive electrode from the negative electrode and allows ions in the electrolyte to pass through.
  • a separator for example, a polyolefin porous film is known, and it is also known to provide various functional layers on the surface of the separator.
  • a functional layer formed on the separator for example, a functional layer obtained by coating and drying a composition for a functional layer containing alumina and resin on a polyethylene separator base material is known.
  • a composition for the functional layer a water-soluble polymer obtained by polymerizing acrylamide, methacrylic acid and dimethylacrylamide, and a polymer obtained by polymerizing n-butyl acrylate, methacrylic acid, acrylonitrile, N-methylolacrylamide and allyl glycidyl ether
  • Patent Document 1 Example 1
  • the functional layer is required to have heat resistance.
  • the above functional layer has a problem of insufficient heat resistance.
  • the separator of the secondary battery must allow ions to pass through for power generation. Therefore, the functional layer is required to have air permeability.
  • the functional layer described above has a problem that it lowers the air permeability of the separator.
  • the functional layer is required to improve adhesion to the separator.
  • the functional layer described above has a problem that the adhesiveness to the separator is not sufficient.
  • composition for the functional layer is required to have storage stability, uniform dispersibility and low viscosity from the viewpoint of productivity of the functional layer.
  • the present invention can obtain a secondary battery separator having excellent heat resistance, air permeability and adhesion, and is also excellent in storage stability, uniform dispersibility and low viscosity.
  • the present invention [1] is a combination of a water-soluble polymer having an SP value of 13.0 (cal/cm 3 ) 1/2 or more and a water-insoluble polymer having an SP value of less than 13.0 (cal/cm 3 ) 1/2 .
  • a conjugated polymer wherein the water-soluble polymer includes a first reactive functional group; the water-insoluble polymer includes a second reactive functional group capable of chemically bonding to the first reactive functional group;
  • the polymer contains a coating material raw material for a secondary battery separator, in which at least part of the first reactive functional groups and at least part of the second reactive functional groups are chemically bonded.
  • the present invention [2] is the above [1], wherein the first reactive functional group of the water-soluble polymer contains a carboxy group, and the second reactive functional group of the water-insoluble polymer contains a glycidyl group. 2. Contains the coating material raw material for the secondary battery separator described in .
  • the water-soluble polymer has repeating units derived from (meth)acrylamide and repeating units derived from a carboxy group-containing vinyl monomer, and the water-insoluble polymer comprises (meth)acryl
  • the water-soluble polymer is 50 parts by mass or more and 99 parts by mass or less relative to the total amount of 100 parts by mass of the water-soluble polymer and the water-insoluble polymer, and the water-insoluble polymer is It contains the coating material raw material for a secondary battery separator according to any one of [1] to [3], which is 1 part by mass or more and 50 parts by mass or less.
  • the present invention [5] is the coating material raw material for a secondary battery separator according to any one of the above [1] to [4], wherein the water-soluble polymer has a weight average molecular weight of 10,000 or more and 200,000 or less. , contains
  • the present invention [6] is the coating material raw material for a secondary battery separator according to any one of the above [1] to [5], wherein the glass transition temperature of the water-soluble polymer is 150 ° C. or higher and 240 ° C. or lower. , contains
  • the present invention [7] is the secondary battery separator coat according to any one of the above [1] to [6], wherein the water-insoluble polymer has a glass transition temperature of ⁇ 40° C. or higher and 50° C. or lower. Contains raw materials.
  • the present invention [8] includes a secondary battery separator coating material comprising the secondary battery separator coating material raw material according to any one of [1] to [7] above.
  • the present invention [9] further includes the secondary battery separator coating material according to [8] above, which contains an inorganic filler and a dispersant.
  • the present invention is a secondary battery separator comprising a porous film and a coated film of the secondary battery separator coating material according to [8] or [9] disposed on at least one side of the porous film. , contains
  • the present invention [11] comprises a step of preparing a porous membrane, and a step of applying the secondary battery separator coating material according to [8] or [9] above to at least one side of the porous membrane.
  • a method of making a secondary battery separator is included.
  • the present invention includes a secondary battery comprising a positive electrode, a negative electrode, and the secondary battery separator described in [10] above disposed between the positive electrode and the negative electrode.
  • the secondary battery separator coating material raw material of the present invention comprises a composite polymer of a water-soluble polymer and a water-insoluble polymer, the water-soluble polymer comprises a first reactive functional group, and the water-insoluble polymer comprises a first including a second reactive functional group capable of chemically bonding to the reactive functional group, wherein at least a portion of the first reactive functional group and at least a portion of the second reactive functional group are chemically bonded in the composite polymer; there is
  • the coating material raw material for secondary battery separators of the present invention is excellent in storage stability, uniform dispersibility and low viscosity. Furthermore, according to the coating material raw material for a secondary battery separator of the present invention, a secondary battery separator excellent in heat resistance, air permeability and adhesion can be obtained.
  • the secondary battery separator coating material of the present invention contains the above-described secondary battery separator coating material raw material, productivity of the secondary battery separator can be improved. Furthermore, the coating material for a secondary battery separator of the present invention can provide a secondary battery separator that is excellent in heat resistance, air permeability and adhesion.
  • the secondary battery separator of the present invention includes the coating film of the secondary battery separator coating material, it is excellent in productivity, heat resistance, air permeability and adhesion.
  • a secondary battery separator excellent in heat resistance, air permeability and adhesion can be efficiently manufactured.
  • the secondary battery of the present invention includes the secondary battery separator described above, it is excellent in productivity, heat resistance, air permeability, and adhesion. As a result, the secondary battery of the present invention is excellent in productivity, heat resistance, air permeability and adhesion.
  • the coating material raw material for secondary battery separators of the present invention contains a composite polymer of a water-soluble polymer and a water-insoluble polymer.
  • a composite polymer includes a water-soluble polymer and a water-insoluble polymer, and the water-soluble polymer and the water-insoluble polymer are chemically bonded. That is, a composite polymer is formed by chemically bonding a water-soluble polymer and a water-insoluble polymer.
  • the water-soluble polymer is a polymer that improves the solubility in water of the coating material raw material for the secondary battery separator.
  • the water-soluble polymer is relatively hydrophilic, and the SP value (solubility parameter) of the water-soluble polymer is 13.0 (cal/cm 3 ) 1/2 or more.
  • the SP value can be calculated using Million Zillion Software's calculation software CHEOPS (version 4.0).
  • the calculation method used in the calculation software is described in Computational Materials Science of Polymers (AA Askadskii, Cambridge Intl Science Pub (2005/12/30)) Chapter XII (same below).
  • the SP value (solubility parameter) of the water-soluble polymer is 13.0 (cal/cm 3 ) 1/2 or more, preferably 13.2 (cal/cm 3 ) 1/2 or more, and more Preferably, it is 13.4 (cal/cm 3 ) 1/2 or more.
  • the SP value (solubility parameter) of the water-soluble polymer is, for example, 20.0 (cal/cm 3 ) 1/2 or less, preferably 18.0 (cal/cm 3 ) 1/2 or less, more preferably , 16.0 (cal/cm 3 ) 1/2 or less.
  • the water-soluble polymer contains a first reactive functional group.
  • the first reactive functional group is a functional group for chemically bonding to a second reactive functional group (described later) of a water-insoluble polymer (described later).
  • Examples of the first reactive functional groups include carboxy groups, hydroxyl groups, glycidyl groups, isocyanate groups and phosphoric acid groups. From the viewpoint of ease of production of the composite polymer, the first reactive functional group is preferably a carboxy group.
  • a water-soluble polymer is obtained by polymerizing a water-soluble polymer raw material (monomer composition) by a known method.
  • the water-soluble polymer raw material is appropriately selected so that the SP value of the water-soluble polymer is within the above range and the first reactive functional group is contained in the water-soluble polymer.
  • the water-soluble polymer raw material contains, for example, (meth)acrylamide and a monomer containing a first reactive functional group.
  • (meth)acryl means acryl and/or methacryl (the same shall apply hereinafter).
  • the water-solubility (SP value) can be well adjusted because the water-soluble polymer has repeating units derived from (meth)acrylamide.
  • (Meth)acrylamide includes acrylamide and methacrylamide, preferably methacrylamide.
  • the first reactive functional group-containing monomer is a monomer containing the above-described first reactive functional group and an ethylenic double bond.
  • the first reactive functional group-containing monomer include carboxy group-containing vinyl monomers, hydroxyl group-containing vinyl monomers, glycidyl group-containing vinyl monomers, isocyanate group-containing vinyl monomers, and phosphoric acid group-containing vinyl monomers.
  • Carboxy group-containing vinyl monomers include, for example, monocarboxylic acids, dicarboxylic acids, and salts thereof.
  • monocarboxylic acids include (meth)acrylic acid.
  • Dicarboxylic acids include, for example, itaconic acid, maleic acid, fumaric acid, itaconic anhydride, maleic anhydride and fumaric anhydride. These can be used alone or in combination of two or more.
  • hydroxyl group-containing vinyl monomers examples include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-methyl-2-hydroxyethyl (meth)acrylate, 2-hydroxy Propyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate can be mentioned.
  • glycidyl group-containing vinyl monomers examples include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and allyl glycidyl ether.
  • isocyanate group-containing vinyl monomers examples include isocyanatomethyl (meth) acrylate, 2-isocyanatoethyl (meth) acrylate, 3-isocyanatopropyl (meth) acrylate, 1-methyl-2-isocyanatoethyl (meth) acrylates, 2-isocyanatopropyl (meth)acrylate, and 4-isocyanatobutyl (meth)acrylate.
  • phosphate group-containing vinyl monomers examples include acid phosphooxyethyl (meth)acrylate and mono(2-hydroxyethyl (meth)acrylate) phosphate.
  • first reactive functional group-containing monomers can be used alone or in combination of two or more.
  • the types of first reactive functional group-containing monomers are appropriately selected so that the first reactive functional groups do not bond to each other.
  • a vinyl monomer containing a carboxy group is preferably used as the first reactive functional group-containing monomer. If the water-soluble polymer raw material contains a carboxyl group-containing vinyl monomer, the water-soluble polymer has repeating units derived from the carboxyl group-containing vinyl monomer, so that excellent water solubility can be obtained.
  • the water-soluble polymer raw material can contain a copolymerizable monomer (hereinafter referred to as a first copolymerizable monomer) as an optional component.
  • a copolymerizable monomer hereinafter referred to as a first copolymerizable monomer
  • the first copolymerizable monomer include monomers copolymerizable with (meth)acrylamide and/or the first reactive functional group-containing monomer.
  • Examples of the first copolymerizable monomer include (meth)acrylic acid alkyl esters.
  • (Meth)acrylic acid alkyl esters include, for example, alkyl (meth)acrylates having an alkyl portion having 1 to 20 carbon atoms.
  • alkyl (meth)acrylates examples include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, ) acrylate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate ) acrylate, dodecyl (meth)acrylate, and octadecyl (meth)acrylate. These can be used alone or in combination of two or more.
  • Examples of the first copolymerizable monomer include a tertiary amino group-containing vinyl monomer, a quaternary ammonium group-containing vinyl monomer, a cyano group-containing vinyl monomer, a sulfonic acid group-containing vinyl monomer, and an acetoacetoxy group-containing vinyl monomer. is mentioned.
  • Examples of tertiary amino group-containing vinyl monomers include N,N-dialkylaminoalkyl(meth)acrylates and N,N-dialkylaminoalkyl(meth)acrylamides.
  • Examples of N,N-dialkylaminoalkyl (meth)acrylates include N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate.
  • N,N-di-t-butylaminoethyl (meth)acrylate, and N,N-dimethylaminobutyl (meth)acrylate are examples of tertiary amino group-containing vinyl monomers.
  • N,N-dialkylaminoalkyl (meth)acrylamides include N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, and N,N-dimethylaminopropyl (meth)acrylamide. ) acrylamide.
  • quaternary ammonium group-containing vinyl monomers examples include quaternized products obtained by reacting the above-mentioned tertiary amino group-containing monomers with a quaternizing agent.
  • Quaternizing agents include, for example, epihalohydrins, benzyl halides and alkyl halides.
  • cyano group-containing vinyl monomers examples include (meth)acrylonitrile.
  • sulfonic acid group-containing vinyl monomers examples include allylsulfonic acid, methallylsulfonic acid, and acrylamido-t-butylsulfonic acid.
  • a salt is also mentioned as a sulfonic-acid-group-containing vinyl monomer. Salts include, for example, sodium, potassium and ammonium salts. More specific examples of salts of sulfonic acid group-containing monomers include sodium allylsulfonate, sodium methallylsulfonate, and ammonium methallylsulfonate.
  • acetoacetoxy group-containing vinyl monomers examples include acetoacetoxyethyl (meth)acrylate.
  • examples of the first copolymerizable monomer include vinyl esters, aromatic vinyl monomers, unsaturated carboxylic acid amides (excluding (meth)acrylamide), heterocyclic vinyl compounds, vinylidene halide compounds, ⁇ - Also included are olefins, dienes, and crosslinkable vinyl monomers.
  • Vinyl esters include, for example, vinyl acetate and vinyl propionate.
  • Aromatic vinyl monomers include, for example, styrene, ⁇ -methylstyrene, p-methylstyrene, vinyltoluene and chlorostyrene.
  • examples of unsaturated carboxylic acid amides include N-methylol(meth)acrylamide.
  • Heterocyclic vinyl compounds include, for example, vinylpyrrolidone.
  • Vinylidene halide compounds include, for example, vinylidene chloride and vinylidene fluoride.
  • Alpha-olefins include, for example, ethylene and propylene. Examples of dienes include butadiene.
  • Crosslinkable vinyl monomers include, for example, methylenebis(meth)acrylamide, divinylbenzene, polyethylene glycol chain-containing di(meth)acrylates, trimethylolpropane tetraacrylate, pentaerythritol triacrylate and pentaerythritol tetraacrylate.
  • first copolymerizable monomers can be used alone or in combination of two or more.
  • the first copolymerizable monomer is preferably a tertiary amino group-containing vinyl monomer.
  • a first reactive functional group-containing monomer containing a first reactive functional group of the type is classified as a first copolymerizable monomer.
  • the first copolymerizable monomer is preferably the hydroxyl group-containing vinyl monomer described above as the first reactive group-containing monomer.
  • the first copolymerizable monomer does not contain a (meth)acrylic acid alkyl ester. That is, the water-soluble polymer raw material preferably does not contain a (meth)acrylic acid alkyl ester. More specifically, the monomer composition containing no (meth)acrylic acid alkyl ester is preferably a water-soluble polymer raw material, which is distinguished from the water-insoluble polymer raw material described below.
  • the ratio of each monomer is appropriately selected so that the SP value of the water-soluble polymer is within the above range and the water-soluble polymer contains the above first reactive functional group.
  • the water-soluble polymer raw material consists of (meth)acrylamide and a first reactive functional group-containing monomer, or (meth)acrylamide, a first reactive functional group-containing monomer and a first copolymerizable monomer.
  • the water-soluble polymer raw material preferably consists of (meth)acrylamide and a carboxy group-containing vinyl monomer, or (meth)acrylamide, a carboxy group-containing vinyl monomer and a first copolymerizable monomer.
  • the content of (meth)acrylamide is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, more preferably 50 parts by mass or more, and more preferably 60 parts by mass or more, more preferably 70 parts by mass or more.
  • the content of (meth)acrylamide is, for example, 97 parts by mass or less, preferably 96 parts by mass or less, more preferably 96 parts by mass or less, with respect to 100 parts by mass of the total amount of the water-soluble polymer raw material. is 95 parts by mass or less.
  • the content of the first reactive functional group-containing monomer is, for example, 3 parts by mass or more, preferably 8 parts by mass or more, more preferably 10 parts by mass with respect to 100 parts by mass of the total amount of the water-soluble polymer raw material. That's it. Further, the content of the first reactive functional group-containing monomer is, for example, 60 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass with respect to 100 parts by mass of the total amount of the water-soluble polymer raw material. Below, more preferably, it is 20 mass parts or less.
  • the content of the first copolymerizable monomer is, for example, 40 parts by mass or less, preferably 20 parts by mass or less, more preferably 100 parts by mass in total of the water-soluble polymer raw material. , 15 parts by mass or less, for example, 0 parts by mass or more.
  • the water-soluble polymer is obtained by polymerizing the water-soluble polymer raw material described above by the method described later.
  • the content of repeating units derived from each monomer in the water-soluble polymer is the same as the content of each monomer in the water-soluble polymer raw material.
  • the content of repeating units derived from (meth)acrylamide is, for example, 40% by mass or more, preferably 50% by mass or more, relative to the total amount of the water-soluble polymer. It is preferably 60% by mass or more, more preferably 70% by mass or more.
  • the content of repeating units derived from (meth)acrylamide is, for example, 97% by mass or less, preferably 96% by mass or less, or more, relative to the total amount of the water-soluble polymer. Preferably, it is 95% by mass or less.
  • the content of the repeating unit derived from the first reactive functional group-containing monomer is, for example, 3% by mass or more, preferably 8% by mass or more, more preferably 10% by mass, relative to the total amount of the water-soluble polymer. % or more. Further, the content of repeating units derived from the first reactive functional group-containing monomer is, for example, 60% by mass or less, preferably 40% by mass or less, more preferably 30% by mass, relative to the total amount of the water-soluble polymer. % or less, more preferably 20 mass % or less.
  • the content of repeating units derived from the first copolymerizable monomer is, for example, 40% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total amount of the water-soluble polymer. and, for example, 0% by mass or more.
  • the weight average molecular weight of the water-soluble polymer is, from the viewpoint of heat resistance and air permeability, for example, 5,000 or more, preferably 10,000 or more, and more preferably, 30,000 or more, more preferably 50,000 or more.
  • the weight average molecular weight of the water-soluble polymer is, for example, 500,000 or less, preferably 200,000 or less, more preferably 15, from the viewpoint of low viscosity. 10,000 or less, more preferably 100,000 or less, and particularly preferably 80,000 or less.
  • weight-average molecular weight of the water-soluble polymer is within the above range, improvement in storage stability, uniform dispersibility and low viscosity can be achieved.
  • the method for measuring the weight-average molecular weight conforms to the examples described later.
  • the glass transition temperature of the water-soluble polymer is, for example, 100° C. or higher, preferably 150° C. or higher, more preferably 200° C. or higher, and still more preferably 210° C. or higher. . Further, the glass transition temperature of the water-soluble polymer is, for example, 300° C. or lower, preferably 240° C. or lower, more preferably 230° C., from the viewpoint of the flexibility of the coating layer coated with the secondary battery separator coating material. °C or less, more preferably 220 °C or less.
  • the glass transition temperature of the water-soluble polymer is within the above range, it is possible to obtain a secondary battery separator having heat resistance, air permeability and adhesion, and further improve storage stability, uniform dispersibility and low viscosity. can be planned.
  • the glass transition temperature is calculated by the FOX formula (the same applies hereinafter).
  • the specific gravity of the water-soluble polymer is, for example, 1.02 or more, preferably 1.05 or more. Also, the specific gravity of the water-soluble polymer is, for example, 1.20 or less, preferably 1.15 or less.
  • the water-insoluble polymer is a polymer that improves the adhesion of the coating material raw material for secondary battery separators.
  • the water-insoluble polymer is relatively hydrophobic, and the SP value (solubility parameter) of the water-insoluble polymer is less than 13.0 (cal/cm 3 ) 1/2 .
  • the SP value (solubility parameter) of the water-insoluble polymer is less than 13.0 (cal/cm 3 ) 1/2 , preferably 12.5 (cal/cm 3 ) 1/2 or less, It is more preferably 12.0 (cal/cm 3 ) 1/2 or less, still more preferably 11.0 (cal/cm 3 ) 1/2 or less.
  • the SP value (solubility parameter) of the water-insoluble polymer is, for example, 7.0 (cal/cm 3 ) 1/2 or more, preferably 8.0 (cal/cm 3 ) 1/2 or more, more preferably is 9.0 (cal/cm 3 ) 1/2 or more.
  • the water-insoluble polymer contains a second reactive functional group.
  • the second reactive functional group is a functional group for chemically bonding to the first reactive functional group of the water-soluble polymer.
  • second reactive functional groups include carboxy groups, hydroxyl groups, glycidyl groups, isocyanate groups and phosphoric acid groups.
  • the second reactive functional group is appropriately selected according to the type of the first reactive functional group.
  • the first reactive functional group contains a carboxyl group
  • a glycidyl group capable of bonding to the carboxyl group is selected as the second reactive functional group.
  • an isocyanate group capable of bonding to the hydroxyl group is selected as the second reactive functional group, for example.
  • the first reactive functional group contains a glycidyl group
  • a carboxyl group and/or a phosphoric acid group capable of bonding to the glycidyl group are selected as the second reactive functional group.
  • the first reactive functional group contains an isocyanate group
  • a hydroxyl group capable of bonding to the isocyanate group is selected as the second reactive functional group.
  • the first reactive functional group contains a phosphoric acid group
  • a glycidyl group capable of bonding to a phosphoric acid group is selected as the second reactive functional group.
  • the second reactive functional group is preferably a glycidyl group.
  • a water-insoluble polymer is obtained by polymerizing a water-insoluble polymer raw material (monomer composition) by a known method.
  • the water-soluble polymer raw material is appropriately selected so that the SP value of the water-insoluble polymer is within the above range and the second reactive functional group is contained in the water-insoluble polymer.
  • the water-insoluble polymer raw material contains, for example, a (meth)acrylic acid alkyl ester and a monomer containing a second reactive functional group.
  • the water-insoluble polymer raw material contains a (meth)acrylic acid alkyl ester
  • the water-insoluble polymer has a repeating unit derived from the (meth)acrylic acid alkyl ester, so the water-insoluble (SP value) can be adjusted well.
  • (Meth)acrylic acid alkyl esters include, for example, the above-described (meth)acrylic acid alkyl esters, and more specifically, alkyl (meth)acrylates having an alkyl moiety having 1 to 20 carbon atoms. These can be used alone or in combination of two or more.
  • (Meth)acrylic acid alkyl esters preferably include alkyl (meth)acrylates having an alkyl moiety of 1 to 4 carbon atoms, more preferably n-butyl (meth)acrylate.
  • the second reactive functional group-containing monomer is a monomer containing the above-described second reactive functional group and an ethylenic double bond.
  • the second reactive functional group-containing monomer include the above-described carboxy group-containing vinyl monomer, the above-described hydroxyl group-containing vinyl monomer, the above-described glycidyl group-containing vinyl monomer, the above-described isocyanate group-containing vinyl monomer, and the above-described phosphoric acid group-containing monomer.
  • Vinyl monomers are mentioned.
  • These second reactive functional group-containing monomers can be used alone or in combination of two or more.
  • the type of the second reactive functional group-containing monomer is appropriately selected so that the second reactive functional groups do not bond to each other.
  • the second reactive functional group-containing monomer is appropriately selected according to the type of the first reactive functional group-containing monomer. That is, the first reactive functional group and the second reactive functional group are appropriately selected so as to form the above-described combination.
  • the first reactive functional group-containing monomer includes a carboxy group-containing vinyl monomer
  • a glycidyl group-containing vinyl monomer is selected as the second reactive functional group.
  • the first reactive functional group-containing monomer includes a hydroxyl group-containing vinyl monomer
  • an isocyanate group-containing vinyl monomer is selected as the second reactive functional group-containing monomer.
  • the first reactive functional group-containing monomer contains a glycidyl group-containing vinyl monomer, a carboxyl group-containing vinyl monomer and/or a phosphoric acid group-containing vinyl monomer are selected as the second reactive functional group-containing monomer.
  • the first reactive functional group-containing monomer includes an isocyanate group-containing vinyl monomer
  • a hydroxyl group-containing vinyl monomer is selected as the second reactive functional group-containing monomer.
  • a glycidyl group-containing vinyl monomer is selected as the second reactive functional group-containing monomer in which the first reactive functional group-containing monomer includes a phosphoric acid group-containing vinyl monomer.
  • a glycidyl group-containing vinyl monomer is preferably used as the second reactive functional group-containing monomer. If the water-insoluble polymer raw material contains a glycidyl group-containing vinyl monomer, the water-insoluble polymer has repeating units derived from the glycidyl group-containing vinyl monomer, so that a composite polymer can be obtained with good productivity.
  • the water-insoluble polymer raw material can contain a copolymerizable monomer (hereinafter referred to as a second copolymerizable monomer) as an optional component.
  • a copolymerizable monomer hereinafter referred to as a second copolymerizable monomer
  • examples of the second copolymerizable monomer include monomers copolymerizable with (meth)acrylic acid alkyl esters and/or second reactive functional group-containing monomers.
  • Examples of the second copolymerizable monomer include the above-described tertiary amino group-containing vinyl monomer, the above-described quaternary ammonium group-containing vinyl monomer, the above-described cyano group-containing vinyl monomer, the above-described sulfonic acid group-containing vinyl monomer, and the above-described Acetoacetoxy group-containing vinyl monomers, the above vinyl esters, the above aromatic vinyl monomers, the above unsaturated carboxylic acid amides (including (meth)acrylamide), the above heterocyclic vinyl compounds, the above vinylidene halide compounds , the above-described ⁇ -olefins, the above-described dienes, and the above-described crosslinkable vinyl monomers.
  • second copolymerizable monomers can be used alone or in combination of two or more.
  • the second copolymerizable monomer is preferably an aromatic vinyl monomer.
  • Second reactive functional group-containing monomers containing a second reactive functional group of the type are classified as second copolymerizable monomers.
  • the second copolymerizable monomer preferably includes the carboxy group-containing vinyl monomer and hydroxyl group-containing vinyl monomer described above as the second reactive group-containing monomer.
  • the water-insoluble polymer raw material preferably does not substantially contain a cyano group-containing vinyl monomer (specifically, (meth)acrylonitrile).
  • a cyano group-containing vinyl monomer specifically, (meth)acrylonitrile.
  • substantially containing no cyano group-containing vinyl monomer means that the cyano group-containing vinyl monomer is, for example, 2.0% by mass or less, preferably 1.0% by mass or less, relative to the water-insoluble polymer raw material. It means that there is When a cyano group-containing vinyl monomer is blended, the electrolytic solution resistance of the secondary battery separator coating material (described later) may be lowered. Therefore, the water-insoluble polymer raw material preferably does not contain a cyano group-containing vinyl monomer.
  • the ratio of each monomer is appropriately selected so that the SP value of the water-insoluble polymer is within the above range and the water-insoluble polymer contains the above second reactive functional group.
  • the water-insoluble polymer raw material consists of a (meth)acrylic acid alkyl ester and a second reactive functional group-containing monomer, or alternatively, a (meth)acrylic acid alkyl ester, a second reactive functional group-containing monomer and a second It consists of copolymerizable monomers.
  • the water-insoluble polymer raw material preferably consists of a (meth)acrylic acid alkyl ester and a glycidyl group-containing vinyl monomer, or from a (meth)acrylic acid alkyl ester, a glycidyl group-containing vinyl monomer and a second copolymerizable monomer.
  • the content of the (meth)acrylic acid alkyl ester is, for example, 20 parts by mass or more, preferably 30 parts by mass or more with respect to 100 parts by mass of the water-insoluble polymer raw material, from the viewpoint of obtaining excellent adhesion. be.
  • the content of the (meth)acrylic acid alkyl ester is, for example, 99 parts by mass or less, preferably 90 parts by mass or less, with respect to 100 parts by mass of the water-insoluble polymer raw material. More preferably, it is 80 parts by mass or less, and still more preferably 70 parts by mass or less.
  • the content ratio (total amount) of the second reactive functional group-containing monomer is, for example, 1 part by mass or more, preferably 2 parts by mass or more, more preferably 3 parts by mass with respect to 100 parts by mass of the water-insoluble polymer raw material. It is at least 4 parts by mass, more preferably at least 4 parts by mass.
  • the content ratio (total amount) of the second reactive functional group-containing monomer is, for example, 30 parts by mass or less, preferably 20 parts by mass or less, more preferably 10 parts by mass or less with respect to 100 parts by mass of the water-insoluble polymer raw material. Part by mass or less.
  • the content of the second copolymerizable monomer is, for example, 0 parts by mass or more, preferably 10 parts by mass or more, with respect to the total amount of 100 parts by mass of the water-insoluble polymer raw material. Preferably, it is 20 parts by mass or more, more preferably 30 parts by mass or more.
  • the content of the second copolymerizable monomer is, for example, 80 parts by mass or less, preferably 70 parts by mass or less, with respect to 100 parts by mass of the total water-insoluble polymer raw material. .
  • the water-insoluble polymer is obtained by polymerizing the water-insoluble polymer raw material described above by the method described later.
  • the content of repeating units derived from each monomer in the water-insoluble polymer is the same as the content of each monomer in the water-insoluble polymer raw material.
  • the content of the repeating unit derived from the (meth)acrylic acid alkyl ester is, for example, 20% by mass or more, preferably 40% by mass, with respect to the total amount of the water-insoluble polymer, from the viewpoint of obtaining excellent adhesion. % or more. Further, the content of repeating units derived from (meth)acrylic acid alkyl ester is, for example, 99% by mass or less, preferably 90% by mass or less, more preferably 80% by mass, relative to the total amount of the water-insoluble polymer. % or less, more preferably 70 mass % or less.
  • the content of the repeating unit derived from the second reactive functional group-containing monomer is, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass, relative to the total amount of the water-insoluble polymer. It is at least 4% by mass, more preferably at least 4% by mass.
  • the content of repeating units derived from the second reactive functional group-containing monomer is, for example, 30% by mass or less, preferably 20% by mass or less, more preferably 20% by mass or less, relative to the total amount of the water-insoluble polymer. , 10 parts by mass or less.
  • the content of the repeating unit derived from the first copolymerizable monomer is, for example, 0% by mass or more, preferably 10% by mass or more, more preferably 20% by mass, relative to the total amount of the water-insoluble polymer. More preferably, it is 30% by mass or more and, for example, 70% by mass or less.
  • the content of repeating units derived from the second copolymerizable monomer is, for example, 0% by mass or more, preferably 10% by mass or more, more preferably 20% by mass, relative to the total amount of the water-insoluble polymer. Above, more preferably 30% by mass or more.
  • the content of repeating units derived from the second copolymerizable monomer is, for example, 80% by mass or less, preferably 70% by mass or less, relative to the total amount of the water-insoluble polymer.
  • the glass transition temperature of the water-insoluble polymer is, from the viewpoint of air permeability and adhesion, for example, ⁇ 60° C. or higher, preferably ⁇ 40° C. or higher, more preferably ⁇ 20° C. or higher, further preferably 0° C. or higher. is. Further, the glass transition temperature of the water-insoluble polymer is, from the viewpoint of low viscosity and adhesion, for example, 70° C. or lower, preferably 50° C. or lower, more preferably 30° C. or lower, and still more preferably 10° C. or lower. be.
  • the glass transition temperature of the water-insoluble polymer is within the above range, it is possible to obtain a secondary battery separator having heat resistance, air permeability, and adhesion, and further improve storage stability, uniform dispersibility, and low viscosity. can be achieved.
  • the specific gravity of the water-insoluble polymer is, for example, 0.85 or more, preferably 0.89 or more. Moreover, the specific gravity of the water-insoluble polymer is, for example, 0.98 or less, preferably 0.95 or less.
  • the difference between the specific gravity of the water-soluble polymer and the specific gravity of the water-insoluble polymer is, for example, 0.04 or more, preferably 0.10 or more. Also, the difference between the specific gravity of the water-soluble polymer and the specific gravity of the water-insoluble polymer is, for example, 0.35 or less, preferably 0.25 or less.
  • methods for producing the composite polymer and the coating material raw material for the secondary battery separator include, for example, the first method and the second method.
  • first method for example, a water-soluble polymer raw material is polymerized to obtain a water-soluble polymer, and then a water-insoluble polymer raw material is polymerized in the presence of the water-soluble polymer.
  • second method first, a water-insoluble polymer raw material is polymerized to obtain a water-insoluble polymer, and then the water-soluble polymer raw material is polymerized in the presence of the water-insoluble polymer.
  • the first method is preferred.
  • the first method comprises a step of obtaining a water-soluble polymer by polymerizing a water-soluble polymer raw material (first step), and obtaining a water-soluble polymer by polymerizing a water-insoluble polymer raw material in the presence of the water-soluble polymer. and a step of chemically bonding at least part of the first reactive functional group and at least part of the second reactive functional group (second step).
  • a water-soluble polymer raw material is polymerized to obtain a water-soluble polymer.
  • water is blended with a known polymerization initiator, and the water-soluble polymer raw material is dropped into the water to polymerize the water-soluble polymer raw material.
  • a known emulsifier surfactant
  • surfactant can be blended, if necessary, from the viewpoint of improving production stability.
  • the polymerization conditions are appropriately set according to the type of water-soluble polymer raw material.
  • the polymerization temperature is, for example, 30° C. or higher, preferably 50° C. or higher.
  • the polymerization temperature is, for example, 95° C. or lower, preferably 85° C. or lower.
  • the polymerization time is, for example, 1 hour or more, preferably 2 hours or more.
  • the polymerization time is, for example, 30 hours or less, preferably 20 hours or less.
  • additives in the polymerization of the water-insoluble polymer, for example, known additives can be blended in an appropriate proportion from the viewpoint of improving production stability.
  • Additives include, for example, pH adjusters, metal ion sequestrants, and molecular weight adjusters (chain transfer agents).
  • the water-soluble polymer raw material is polymerized to obtain a water-soluble polymer.
  • the water-soluble polymer has repeating units derived from the first reactive functional group-containing monomer. That is, the water-soluble polymer contains a first reactive functional group in its molecule.
  • the water-soluble polymer is obtained as an aqueous solution dissolved in water.
  • the solid content concentration of the water-soluble polymer is appropriately set according to the purpose and application.
  • the water-insoluble polymer raw material is polymerized in the presence of the water-soluble polymer. More specifically, the water-insoluble polymer raw material is emulsified in water, and the emulsion is added to the aqueous solution of the water-soluble polymer to polymerize the water-insoluble polymer raw material.
  • the polymerization conditions are appropriately set according to the type of water-insoluble polymer raw material.
  • the polymerization temperature is, for example, 30° C. or higher, preferably 50° C. or higher.
  • the polymerization temperature is, for example, 95° C. or lower, preferably 85° C. or lower.
  • the polymerization time is, for example, 0.5 hours or longer, preferably 1.5 hours or longer.
  • the polymerization time is, for example, 20 hours or less, preferably 10 hours or less.
  • the water-insoluble polymer raw material is polymerized to obtain a water-insoluble polymer.
  • the water-insoluble polymer has repeating units derived from the second reactive functional group-containing monomer. That is, the water-insoluble polymer contains a second reactive functional group in its molecule.
  • the first reactive functional group when the first reactive functional group contains a carboxy group, the carboxy group chemically bonds with the glycidyl group as the second reactive functional group. Also, for example, when the first reactive functional group contains a hydroxyl group, the hydroxyl group chemically bonds with the isocyanate group as the second reactive functional group. Also, for example, when the first reactive functional group contains a glycidyl group, the glycidyl group chemically bonds with the carboxyl group and/or the phosphoric acid group as the second reactive functional group. Also, for example, when the first reactive functional group contains an isocyanate group, the isocyanate group chemically bonds with the hydroxyl group as the second reactive functional group. Also, for example, the first reactive functional group includes a phosphate group, and the phosphate group is chemically bonded to the glycidyl group as the second reactive functional group.
  • reaction conditions are appropriately set according to the type of the first reactive functional group and the type of the second reactive functional group.
  • the reaction of the first reactive functional group and the second reactive functional group usually proceeds simultaneously with the synthesis of the water-insoluble polymer in the second step.
  • the water-soluble polymer and the water-insoluble polymer can be chemically bonded to obtain a composite polymer of the water-soluble polymer and the water-insoluble polymer.
  • a dispersion containing the composite polymer (coating material raw material for secondary battery separator) is obtained.
  • the content of the coating material raw material for the secondary battery separator (the solid content concentration of the dispersion) is, for example, 5% by mass or more and, for example, 50% by mass or less.
  • the mass ratio of the water-soluble polymer to the water-insoluble polymer is appropriately set according to the purpose and application.
  • the total amount of the water-soluble polymer and the water-insoluble polymer is 100 parts by mass, and from the viewpoint of heat resistance, the water-soluble polymer is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, more preferably 60 parts by mass. It is at least 70 parts by mass, more preferably at least 80 parts by mass.
  • the water-soluble polymer is, for example, 99.9 parts by mass or less, preferably 99 parts by mass or less, with respect to the total amount of 100 parts by mass of the water-soluble polymer and the water-insoluble polymer. More preferably, it is 97 parts by mass or less, and still more preferably 95 parts by mass or less.
  • the water-insoluble polymer is, for example, 0.1 part by mass or more, preferably 1 part by mass or more, relative to the total amount of 100 parts by mass of the water-soluble polymer and the water-insoluble polymer. , more preferably 3 parts by mass or more, more preferably 5 parts by mass or more.
  • the water-insoluble polymer is, for example, 60 parts by mass or less, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, more preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less.
  • the mass of the water-insoluble polymer and the mass of the water-soluble polymer can be calculated from the amounts of the water-insoluble polymer raw material and the water-soluble polymer raw material. That is, the weight of the water-soluble polymer means the weight of the water-soluble polymer raw material, and the weight of the water-insoluble polymer means the weight of the water-insoluble polymer raw material.
  • the raw material for the coating material for the secondary battery separator of the present invention contains a composite polymer of a water-soluble polymer and a water-insoluble polymer, the water-soluble polymer contains a first reactive functional group, and the water-insoluble polymer is comprising a second reactive functional group capable of chemically bonding to the first reactive functional group, wherein at least a portion of the first reactive functional group and at least a portion of the second reactive functional group are chemically bonded in the composite polymer; doing.
  • the raw material for the secondary battery separator coating material is excellent in storage stability, uniform dispersibility and low viscosity. Furthermore, according to the raw material for the secondary battery separator coating material, it is possible to obtain a secondary battery separator that is excellent in heat resistance, air permeability, and adhesion.
  • the water-soluble polymer and the water-insoluble polymer are chemically bonded to form a composite polymer, so separation due to the difference in specific gravity can be suppressed, and it is excellent. Provides storage stability. Furthermore, since the water-soluble polymer and the water-insoluble polymer are chemically bonded to form a composite polymer, no mixing step is required during use, and workability and uniform dispersibility are excellent.
  • the water-soluble polymer and the water-insoluble polymer are chemically bonded to form a composite polymer, so the water-soluble polymer is fixed to the water-insoluble polymer. be done. Therefore, the interaction between the water-soluble polymers is suppressed, and as a result, an increase in viscosity is suppressed and excellent low viscosity is obtained.
  • the secondary battery separator coating material of the present invention contains the above-described secondary battery separator coating material raw material, and, if necessary, an inorganic filler and a dispersant.
  • the mixing ratio of the secondary battery separator coating material raw material is the total amount of the secondary battery separator coating material raw material, the inorganic filler, and the dispersant (hereinafter referred to as the secondary battery separator coating material component.
  • solid content for 100 parts by mass (solid content), for example, 0.1 parts by mass or more (solid content), and for example, 10 parts by mass or less (solid content).
  • Inorganic fillers include, for example, oxides, nitrides, carbides, sulfates, hydroxides, silicates and minerals.
  • Oxides include, for example, alumina, silica, titania, zirconia, magnesia, ceria, yttria, zinc oxide and iron oxide.
  • Nitrides include, for example, silicon nitride, titanium nitride and boron nitride.
  • Carbides include, for example, silicon carbide and calcium carbonate.
  • Sulfates include, for example, magnesium sulfate and aluminum sulfate.
  • Hydroxides include, for example, aluminum hydroxide and aluminum oxide hydroxide.
  • Silicates include, for example, calcium silicate, magnesium silicate, diatomaceous earth, silica sand and glass.
  • Minerals include, for example, talc, kaolinite, dekite, nacrite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite, asbestos and zeolites.
  • Inorganic fillers preferably include oxides and hydroxides, more preferably aluminum oxides and aluminum oxide hydroxides.
  • the mixing ratio of the inorganic filler is, for example, 50 parts by mass or more (solid content) with respect to 100 parts by mass (solid content) of the coating material component for the secondary battery separator, and, for example, 99.7 parts by mass or less. (solid content).
  • Dispersants include, for example, ammonium polycarboxylate and sodium polycarboxylate.
  • the dispersant is ammonium polycarboxylate
  • the raw material for the secondary battery separator coating material and the inorganic filler can be uniformly dispersed, and a coating film (described later) having a uniform thickness can be obtained.
  • the mixing ratio of the dispersant is, for example, 0.1 parts by mass or more (solid content) with respect to 100 parts by mass (solid content) of the secondary battery separator coating material component, and for example, 5 parts by mass or less ( solid content).
  • an inorganic filler and a dispersant are blended with water in the above proportions to prepare an inorganic filler dispersion.
  • the raw material for the coating material for the secondary battery separator (or the dispersion containing the raw material for the coating material for the secondary battery separator) is blended with the inorganic filler dispersion in the above ratio and stirred. Thereby, the coating material for secondary battery separators is obtained.
  • the stirring method is not particularly limited, and a known stirring device is used.
  • Agitation devices include, for example, ball mills, bead mills, planetary ball mills, vibrating ball mills, sand mills, colloid mills, attritors, roll mills, high speed impeller dispersers, dispersers, homogenizers, high speed impact mills, ultrasonic dispersers and stirring blades.
  • the secondary battery separator coating material is obtained, for example, as a dispersion liquid dispersed in water.
  • the coating material for the secondary battery separator can contain known additives, if necessary.
  • Additives include, for example, hydrophilic resins, thickeners, wetting agents, antifoaming agents and pH adjusters. Additives can be used singly or in combination of two or more.
  • the secondary battery separator coating material contains the above secondary battery separator coating material raw material, productivity of the secondary battery separator can be improved. Furthermore, the secondary battery separator coating material described above provides a secondary battery separator that is excellent in heat resistance, gas permeability and adhesion.
  • this secondary battery separator coating material can be suitably used as a secondary battery separator coating material.
  • the secondary battery separator of the present invention can be produced by a known method.
  • Porous membranes include, for example, polyolefin porous membranes and aromatic polyamide porous membranes, preferably polyolefin porous membranes.
  • Polyolefins include, for example, polyethylene and polypropylene.
  • the porous membrane may be surface-treated as necessary. Surface treatments include, for example, corona treatment and plasma treatment.
  • the thickness of the porous membrane is, for example, 1 ⁇ m or more, preferably 5 ⁇ m or more. Also, the thickness of the porous membrane is, for example, 40 ⁇ m or less, preferably 20 ⁇ m or less.
  • the separator coating material is applied to at least one side of the porous membrane. Thereafter, if necessary, the separator coating material is dried to obtain a coating film.
  • the coating method is not particularly limited, but examples include the gravure coater method, the small diameter gravure coater method, the reverse roll coater method, the transfer roll coater method, the kiss coater method, the dip coater method, the micro gravure coat method, the knife coater method, and the air doctor coater. method, blade coater method, rod coater method, squeeze coater method, cast coater method, die coater method, screen printing method and spray coating method.
  • the drying temperature is, for example, 40°C or higher and, for example, 80°C or lower.
  • the thickness of the coating film after drying is, for example, 1 ⁇ m or more, preferably 2 ⁇ m or more. Moreover, the thickness of the coating film after drying is, for example, 10 ⁇ m or less, preferably 8 ⁇ m or less.
  • a secondary battery separator comprising a porous membrane and a coated film of the above-described secondary battery separator coating material disposed on at least one side of the porous membrane is manufactured.
  • the coating film of the secondary battery separator coating material is arranged on at least one side of the porous membrane, but the above coating film can also be arranged on both sides of the porous membrane.
  • the above secondary battery separator is provided with the coating film of the above secondary battery separator coating material, it is excellent in productivity, heat resistance, air permeability and adhesion.
  • a secondary battery separator having excellent heat resistance, air permeability, and adhesion can be efficiently manufactured.
  • this secondary battery separator can be suitably used as a separator for a secondary battery.
  • the secondary battery of the present invention includes a positive electrode, a negative electrode, the above-described secondary battery separator disposed between the positive electrode and the negative electrode, and an electrolyte impregnated in the positive electrode, the negative electrode, and the above-described secondary battery separator.
  • the positive electrode for example, a known electrode comprising a positive electrode current collector and a positive electrode active material laminated on the positive electrode current collector is used.
  • a known conductive material can be used as the positive electrode current collector.
  • Conductive materials include, for example, aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymers and conductive glasses. These can be used alone or in combination of two or more.
  • the positive electrode active material is not particularly limited, but examples include lithium-containing transition metal oxides, lithium-containing phosphates, and lithium-containing sulfates. These can be used alone or in combination of two or more.
  • the negative electrode for example, a known electrode comprising a negative electrode current collector and a negative electrode active material laminated on the negative electrode current collector is used.
  • Examples of current collectors for negative electrodes include copper and nickel. These can be used alone or in combination of two or more.
  • negative electrode active materials examples include graphite, soft carbon, and hard carbon. These can be used alone or in combination of two or more.
  • the electrolyte may be, for example, a solution in which a lithium salt is dissolved in a carbonate compound.
  • Carbonate compounds include, for example, ethylene carbonate (EC), propylene carbonate (PC) and ethyl methyl carbonate (EMC).
  • the separator of the secondary battery is sandwiched between the positive electrode and the negative electrode, these are housed in a battery housing (cell), and the electrolyte is injected into the battery housing. do.
  • the above secondary battery includes the above secondary battery separator, it is excellent in productivity, heat resistance, air permeability, and adhesion. As a result, the above secondary battery is excellent in productivity, heat resistance, air permeability and adhesion.
  • the water-insoluble polymer raw materials prepared according to the descriptions in Tables 1 to 4 were emulsified with soapy water. Then, the emulsion was added all at once to the aqueous solution of the water-soluble polymer. These mixtures were stirred at 75° C. for 4 hours with stirring to complete the polymerization. As a result, a water-insoluble polymer having a glycidyl group (second reactive functional group) was obtained. At the same time, the carboxy group of the water-soluble polymer and the glycidyl group of the water-insoluble polymer were reacted to obtain a composite polymer in which the water-soluble polymer and the water-insoluble polymer were chemically bonded.
  • the water-insoluble polymers of Comparative Examples 1 to 6 did not have a glycidyl group (second reactive functional group), and the water-insoluble polymer did not react with the water-insoluble polymer. Therefore, in Comparative Examples 1 to 6, a composite polymer was not obtained, and a mixed polymer of a water-soluble polymer and a water-insoluble polymer was obtained.
  • a separator coating material raw material was obtained as a composite polymer dispersion or a mixed polymer dispersion (hereinafter referred to as polymer dispersion).
  • the solid content concentration of the dispersion was 10.0% by mass.
  • glass transition temperature (Tg, unit: °C) of the water-insoluble polymer and the water-soluble polymer was calculated by the following FOX formula.
  • Tg is the glass transition temperature of the copolymer (unit: K)
  • solubility parameters SP value, unit: (cal/cm 3 ) 1/2
  • solubility parameters were calculated using calculation software CHEOPS (version 4.0) of Million Zillion Software.
  • CHEOPS version 4.0
  • the weight average molecular weight of the water-soluble polymer was measured by the following method and conditions. That is, when the polymerization of the water-soluble polymer was completed, the water-soluble polymer was sampled. Next, the weight average molecular weight (Mw) of the sample was determined using a GPC device (device name: PKP-22, Fromm). In addition, the measurement conditions are described below. Also, the weight average molecular weight is a standard polyethylene glycol/polyethylene oxide equivalent molecular weight.
  • Example concentration 0.1 (w/v)%
  • Comparative example 7 A dispersion liquid as a separator coating material raw material was obtained according to Example 1 of International Publication WO2017/026095.
  • a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube is charged with water-soluble polymer raw materials according to Tables 1 to 4, and nitrogen gas is used to remove oxygen in the reaction system. did. Then, with stirring, 7 parts of a 5% aqueous ammonium persulfate solution and 3 parts of a 5% aqueous sodium hydrogen sulfite solution as polymerization initiators were added to the flask, then the temperature was raised from room temperature to 80 ° C. and kept for 3 hours to obtain a water-soluble polymer. The raw material was polymerized. After that, 162 parts of ion-exchanged water was added to obtain an aqueous solution of a water-soluble polymer.
  • the obtained water-soluble polymer dispersion and the water-insoluble polymer dispersion were mixed to obtain a mixed polymer dispersion (polymer dispersion) as a separator coating material raw material.
  • the mixing ratio was such that the particulate polymer was 2 parts by mass with respect to 1 part by mass of the water-soluble polymer.
  • Comparative example 8 A separable flask equipped with a stirrer and reflux cooling was charged with 600 parts of distilled water and 1 part of sodium lauryl sulfate (surfactant), and the temperature was raised to 70°C. Then, potassium persulfate (KPS, polymerization initiator) was added to the separable flask according to Table 5.
  • KPS potassium persulfate
  • the low SP value polymer raw material prepared according to Table 5 was emulsified with 1 part of sodium lauryl sulfate (surfactant). Then, the emulsion was added all at once to the aqueous dispersion of the high SP value polymer. These mixtures were stirred at 75° C. for 4 hours with stirring to complete the polymerization. As a result, a low SP value polymer having a glycidyl group (second reactive functional group) was obtained. Together with this, a core-shell aqueous dispersion was obtained in which a high SP value polymer and a low SP value polymer were bonded via a glycidyl group and a carboxy group.
  • surfactant sodium lauryl sulfate
  • Comparative example 9 A dispersion liquid was obtained as a coating material raw material for a separator according to Example 1 of International Publication WO2010/134501.
  • styrene oligomer was a one-end methacryloyl polystyrene oligomer (manufactured by Toagosei Chemical Industry Co., Ltd., trade name AS-6, SP value 9.9 (cal/cm 3 ) 1/2 ).
  • graft polymer a polymer (hereinafter referred to as graft polymer) solution was obtained.
  • the main chain of the graft polymer was composed of n-butyl acrylate (a component exhibiting swelling properties with respect to electrolyte).
  • the side chains of the graft polymer were composed of styrene (a component that does not swell with the electrolyte).
  • the polymerization conversion rate was calculated from the solid content concentration of the solution.
  • the polymerization addition rate was about 98%.
  • the weight average molecular weight of the graft polymer was about 50,000.
  • the glass transition temperature of the graft polymer was 25°C.
  • the surface of the polyolefin resin porous membrane was corona-treated. More specifically, as a polyolefin resin porous film, product number SW509C+ (film thickness 9.6 ⁇ m, porosity 40.6%, air permeability 158 g/100 ml, surface density 5.5 g/m 2 , Changzhou Xingyuan New Energy Materials Co., Ltd.) was prepared. Next, the surface of the polyolefin resin porous membrane is cut to A4 size, and then the surface of the polyolefin resin porous membrane is treated with a switchback automatic traveling type corona surface treatment device (manufactured by Wedge Co., Ltd.) at an output of 0.15 KW and a conveying speed. Corona treatment was performed under the conditions of 3.0 m/s ⁇ 2 times and a corona discharge distance of 9 mm.
  • a switchback automatic traveling type corona surface treatment device manufactured by Wedge Co., Ltd.
  • the surface of the corona-treated polyolefin resin porous membrane was coated with the above coating material for a secondary battery separator. After coating, the coating was dried at 50° C. to form a coating film of 5 ⁇ m on the surface of the polyolefin resin porous membrane.
  • the heat shrinkage rate was less than 15%.
  • the heat shrinkage rate was 15% or more and less than 25%.
  • the heat shrinkage rate was 25% or more and less than 65%.
  • the heat shrinkage rate was 65% or more and less than 80%.
  • x The heat shrinkage rate was 80% or more.
  • the air resistance was measured according to JIS-P-8117 using an Oken type air permeability smoothness tester manufactured by Asahi Seiko Co., Ltd. It was evaluated that the smaller the air resistance, the better the ion permeability. In addition, the ion permeability was evaluated according to the following criteria.
  • Air resistance was less than 180 s/100 mL.
  • the air resistance was 180 s/100 mL or more and less than 220 s/100 mL.
  • Air permeation resistance was 220 s/100 mL or more and less than 300 s/100 mL.
  • x Air resistance was 300 s/100 mL or more.
  • Adhesion A secondary battery separator was cut into a size of 5 cm ⁇ 10 cm, and this was used as a test piece.
  • a cellophane adhesive tape was attached to the coating film of the secondary battery separator coating material by a method according to JIS Z1522, and a 180° peel test was performed. At that time, the cellophane adhesive tape was pulled at a speed of 10 mm/min. The measurement was performed 3 times and the average value was calculated. In addition, the adhesion was evaluated according to the following criteria.
  • the average adhesive strength was 70 N/m or more.
  • Good The average adhesive strength was 50 N/m or more and less than 70 N/m.
  • ⁇ The average adhesive strength was 20 N/m or more and less than 50 N/m.
  • ⁇ The average adhesive strength was 1/m or more and less than 20 N/m.
  • x The average adhesive strength was less than 1 N/m.
  • Uniform dispersibility of the coating material raw material for the secondary battery separator was evaluated by the following method. That is, the zeta potential of the secondary battery separator coating material was measured 10 times with a zeta potential measuring device (ELSZ-2000 manufactured by Otsuka Electronics Co., Ltd.) in a concentrated cell. Then, uniform dispersibility was evaluated according to the following criteria.
  • A The difference between the maximum value and the minimum value in 10 measurements of zeta potential is less than 5% with respect to the average value of 10 measurements.
  • ⁇ The difference between the maximum value and the minimum value in 10 measurements of zeta potential is 5% or more and less than 10% with respect to the average value of 10 measurements.
  • ⁇ The difference between the maximum value and the minimum value in 10 measurements of zeta potential is 10% or more and less than 15% with respect to the average value of 10 measurements.
  • x The difference between the maximum value and the minimum value in 10 measurements of zeta potential is 15% or more with respect to the average value of 10 measurements.
  • the blending recipe (parts by mass) of the water-soluble polymer raw material in the table indicates the blending amount of the raw material component (monomer) with respect to 100 parts by mass of the water-soluble polymer. Further, the blending recipe (parts by mass) of the water-insoluble polymer raw material indicates the blending amount of the raw material component (monomer) with respect to 100 parts by mass of the water-insoluble polymer. Moreover, the ratio of the water-soluble polymer and the water-insoluble polymer follows "water-insoluble polymer/water-soluble polymer (mass ratio)" in the table.
  • the blending recipe (parts by mass) of the high SP value polymer raw material in the table indicates the blending amount of the raw material component (monomer) per 100 parts by mass of the high SP value polymer.
  • the blending recipe (parts by mass) of the low SP value polymer raw material indicates the blending amount of the raw material component (monomer) with respect to 100 parts by mass of the low SP value polymer.
  • the ratio of the high SP value polymer and the low SP value polymer follows "high SP value polymer/low SP value polymer (mass ratio)" in the table.
  • the secondary battery separator coating material raw material, the secondary battery separator coating material, the secondary battery separator, the method for producing the secondary battery separator, and the secondary battery of the present invention are suitably used in the secondary battery field. .

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Abstract

This coating starting material for a secondary battery separator contains a conjugated polymer of: a water-soluble polymer having an SP value of 13.0 (cal/cm3)1/2 or higher; and a water-insoluble polymer having an SP value less than 13.0(cal/cm3)1/2. The water-soluble polymer contains a first reactive functional group. The water-insoluble polymer contains a second reactive functional group capable of chemically bonding to the first reactive functional group. At least part of the first reactive functional group and at least part of the second reactive functional group are chemically bonded to one another in said conjugated polymer.

Description

二次電池セパレータ用コート材原料、二次電池セパレータ用コート材、二次電池セパレータ、二次電池セパレータの製造方法、および、二次電池Coating material raw material for secondary battery separator, coating material for secondary battery separator, secondary battery separator, method for manufacturing secondary battery separator, and secondary battery
　本発明は、二次電池セパレータ用コート材原料、二次電池セパレータ用コート材、二次電池セパレータ、二次電池セパレータの製造方法、および、二次電池に関する。 The present invention relates to a coating material raw material for a secondary battery separator, a coating material for a secondary battery separator, a secondary battery separator, a method for manufacturing a secondary battery separator, and a secondary battery.
　従来、二次電池内には、正極と負極とを隔離し、電解液中のイオンを通過させるためのセパレータが備えられている。 Conventionally, a secondary battery is equipped with a separator that separates the positive electrode from the negative electrode and allows ions in the electrolyte to pass through.
　このようなセパレータとしては、例えば、ポリオレフィン多孔膜が知られており、また、セパレータの表面に、種々の機能層を設けることが知られている。 As such a separator, for example, a polyolefin porous film is known, and it is also known to provide various functional layers on the surface of the separator.
　セパレータに形成される機能層としては、例えば、アルミナおよび樹脂を含む機能層用組成物を、ポリエチレン製セパレータ基材に塗布および乾燥させて得られる機能層が知られている。機能層用組成物として、アクリルアミド、メタクリル酸およびジメチルアクリルアミドを重合させて得られる水溶性重合体と、ｎ－ブチルアクリレート、メタクリル酸、アクリロニトリル、Ｎ－メチロールアクリルアミドおよびアリルグリシジルエーテルを重合させて得られる粒子状重合体と、アルミナと、分散剤と、界面活性剤との混合物が、提案されている（例えば、特許文献１（実施例１）参照。）。 As the functional layer formed on the separator, for example, a functional layer obtained by coating and drying a composition for a functional layer containing alumina and resin on a polyethylene separator base material is known. As the composition for the functional layer, a water-soluble polymer obtained by polymerizing acrylamide, methacrylic acid and dimethylacrylamide, and a polymer obtained by polymerizing n-butyl acrylate, methacrylic acid, acrylonitrile, N-methylolacrylamide and allyl glycidyl ether A mixture of a particulate polymer, alumina, a dispersant and a surfactant has been proposed (see, for example, Patent Document 1 (Example 1)).
国際公開２０１７／０２６０９５号WO2017/026095
　一方、セパレータの形状が、熱による収縮で変化すると、正極と負極との間でショートする可能性がある。そのため、機能層には、耐熱性が要求される。しかし、上記の機能層は、耐熱性が十分ではないという不具合がある。 On the other hand, if the shape of the separator changes due to shrinkage due to heat, there is a possibility of short-circuiting between the positive electrode and the negative electrode. Therefore, the functional layer is required to have heat resistance. However, the above functional layer has a problem of insufficient heat resistance.
　また、二次電池のセパレータは、発電のためにイオンを通過させる必要がある。そのため、機能層には、透気性が要求される。しかし、上記した機能層は、セパレータの透気性を低下させるという不具合がある。 In addition, the separator of the secondary battery must allow ions to pass through for power generation. Therefore, the functional layer is required to have air permeability. However, the functional layer described above has a problem that it lowers the air permeability of the separator.
　さらに、機能層には、セパレータに対する密着性の向上が要求されている。しかし、上記した機能層は、セパレータに対する密着性が十分ではないという不具合がある。 Furthermore, the functional layer is required to improve adhesion to the separator. However, the functional layer described above has a problem that the adhesiveness to the separator is not sufficient.
　加えて、機能層用組成物には、機能層の生産性の観点から、貯蔵安定性、均一分散性および低粘性が要求されている。 In addition, the composition for the functional layer is required to have storage stability, uniform dispersibility and low viscosity from the viewpoint of productivity of the functional layer.
　本発明は、優れた耐熱性、透気性および密着性を兼ね備える二次電池セパレータを得ることができ、さらに、貯蔵安定性、均一分散性および低粘性にも優れる二次電池セパレータ用コート材原料、その二次電池セパレータ用コート材原料を含む二次電池セパレータ用コート材、その二次電池セパレータ用コート材の塗布膜を備える二次電池セパレータ、その二次電池セパレータの製造方法、および、その二次電池セパレータを備える二次電池である。 The present invention can obtain a secondary battery separator having excellent heat resistance, air permeability and adhesion, and is also excellent in storage stability, uniform dispersibility and low viscosity. Raw material for coating material for secondary battery separator, A coating material for a secondary battery separator containing the raw material for the coating material for the secondary battery separator, a secondary battery separator provided with a coating film of the coating material for the secondary battery separator, a method for manufacturing the secondary battery separator, and the second A secondary battery comprising a secondary battery separator.
　本発明［１］は、ＳＰ値１３．０（ｃａｌ／ｃｍ３）１／２以上の水溶性ポリマーと、ＳＰ値１３．０（ｃａｌ／ｃｍ３）１／２未満の非水溶性ポリマーとの複合ポリマーを含み、前記水溶性ポリマーは、第１反応性官能基を含み、前記非水溶性ポリマーは、前記第１反応性官能基に化学結合可能な第２反応性官能基を含み、前記複合ポリマーにおいて、前記第１反応性官能基の少なくとも一部と、前記第２反応性官能基の少なくとも一部とが化学結合している、二次電池セパレータ用コート材原料を、含んでいる。 The present invention [1] is a combination of a water-soluble polymer having an SP value of 13.0 (cal/cm 3 ) 1/2 or more and a water-insoluble polymer having an SP value of less than 13.0 (cal/cm 3 ) 1/2 . a conjugated polymer, wherein the water-soluble polymer includes a first reactive functional group; the water-insoluble polymer includes a second reactive functional group capable of chemically bonding to the first reactive functional group; The polymer contains a coating material raw material for a secondary battery separator, in which at least part of the first reactive functional groups and at least part of the second reactive functional groups are chemically bonded.
　本発明［２］は、前記水溶性ポリマーの前記第１反応性官能基が、カルボキシ基を含み、前記非水溶性ポリマーの前記第２反応性官能基が、グリシジル基を含む、上記［１］に記載の二次電池セパレータ用コート材原料を、含んでいる。 The present invention [2] is the above [1], wherein the first reactive functional group of the water-soluble polymer contains a carboxy group, and the second reactive functional group of the water-insoluble polymer contains a glycidyl group. 2. Contains the coating material raw material for the secondary battery separator described in .
　本発明［３］は、前記水溶性ポリマーは、（メタ）アクリルアミドに由来する繰り返し単位と、カルボキシ基含有ビニルモノマーに由来する繰り返し単位とを有し、前記非水溶性ポリマーは、（メタ）アクリル酸アルキルエステルに由来する繰り返し単位と、グリシジル基含有ビニルモノマーに由来する繰り返し単位とを有する、上記［１］または［２］に記載の二次電池セパレータ用コート材原料を、含んでいる。 In the present invention [3], the water-soluble polymer has repeating units derived from (meth)acrylamide and repeating units derived from a carboxy group-containing vinyl monomer, and the water-insoluble polymer comprises (meth)acryl The coating material raw material for a secondary battery separator according to [1] or [2] above, which has a repeating unit derived from an acid alkyl ester and a repeating unit derived from a glycidyl group-containing vinyl monomer, is included.
　本発明［４］は、前記水溶性ポリマーおよび前記非水溶性ポリマーの総量１００質量部に対して、前記水溶性ポリマーが、５０質量部以上９９質量部以下であり、前記非水溶性ポリマーが、１質量部以上５０質量部以下である、上記［１］～［３］のいずれか一項に記載の二次電池セパレータ用コート材原料を、含んでいる。 In the present invention [4], the water-soluble polymer is 50 parts by mass or more and 99 parts by mass or less relative to the total amount of 100 parts by mass of the water-soluble polymer and the water-insoluble polymer, and the water-insoluble polymer is It contains the coating material raw material for a secondary battery separator according to any one of [1] to [3], which is 1 part by mass or more and 50 parts by mass or less.
　本発明［５］は、前記水溶性ポリマーの重量平均分子量が、１万以上２０万以下である、上記［１］～［４］のいずれか一項に記載の二次電池セパレータ用コート材原料を、含んでいる。 The present invention [5] is the coating material raw material for a secondary battery separator according to any one of the above [1] to [4], wherein the water-soluble polymer has a weight average molecular weight of 10,000 or more and 200,000 or less. , contains
　本発明［６］は、前記水溶性ポリマーのガラス転移温度が、１５０℃以上２４０℃以下である、上記［１］～［５］のいずれか一項に記載の二次電池セパレータ用コート材原料を、含んでいる。 The present invention [6] is the coating material raw material for a secondary battery separator according to any one of the above [1] to [5], wherein the glass transition temperature of the water-soluble polymer is 150 ° C. or higher and 240 ° C. or lower. , contains
　本発明［７］は、前記非水溶性ポリマーのガラス転移温度が、－４０℃以上５０℃以下である、上記［１］～［６］のいずれか一項に記載の二次電池セパレータ用コート材原料を、含んでいる。 The present invention [7] is the secondary battery separator coat according to any one of the above [1] to [6], wherein the water-insoluble polymer has a glass transition temperature of −40° C. or higher and 50° C. or lower. Contains raw materials.
　本発明［８］は、上記［１］～［７］のいずれか一項に記載の二次電池セパレータ用コート材原料を含む、二次電池セパレータ用コート材を、含んでいる。 The present invention [8] includes a secondary battery separator coating material comprising the secondary battery separator coating material raw material according to any one of [1] to [7] above.
　本発明［９］は、さらに、無機充填剤と分散剤とを含む、上記［８］に記載の二次電池セパレータ用コート材を、含んでいる。 The present invention [9] further includes the secondary battery separator coating material according to [8] above, which contains an inorganic filler and a dispersant.
　本発明［１０］は、多孔膜と、前記多孔膜の少なくとも片面に配置される上記［８］または［９］に記載の二次電池セパレータ用コート材の塗布膜とを備える、二次電池セパレータを、含んでいる。 The present invention [10] is a secondary battery separator comprising a porous film and a coated film of the secondary battery separator coating material according to [8] or [9] disposed on at least one side of the porous film. , contains
　本発明［１１］は、多孔膜を準備する工程、および、前記多孔膜の少なくとも片面に、上記［８］または［９］に記載の二次電池セパレータ用コート材を塗布する工程を備える、二次電池セパレータの製造方法を、含んでいる。 The present invention [11] comprises a step of preparing a porous membrane, and a step of applying the secondary battery separator coating material according to [8] or [9] above to at least one side of the porous membrane. A method of making a secondary battery separator is included.
　本発明［１２］は、正極と、負極と、前記正極および前記負極の間に配置される上記［１０］に記載される二次電池セパレータとを備える、二次電池を、含んでいる。 The present invention [12] includes a secondary battery comprising a positive electrode, a negative electrode, and the secondary battery separator described in [10] above disposed between the positive electrode and the negative electrode.
　本発明の二次電池セパレータ用コート材原料は、水溶性ポリマーと非水溶性ポリマーとの複合ポリマーを含み、水溶性ポリマーは、第１反応性官能基を含み、非水溶性ポリマーは、第１反応性官能基に化学結合可能な第２反応性官能基を含み、複合ポリマーにおいて、第１反応性官能基の少なくとも一部と、第２反応性官能基の少なくとも一部とが化学結合している。 The secondary battery separator coating material raw material of the present invention comprises a composite polymer of a water-soluble polymer and a water-insoluble polymer, the water-soluble polymer comprises a first reactive functional group, and the water-insoluble polymer comprises a first including a second reactive functional group capable of chemically bonding to the reactive functional group, wherein at least a portion of the first reactive functional group and at least a portion of the second reactive functional group are chemically bonded in the composite polymer; there is
　そのため、本発明の二次電池セパレータ用コート材原料は、貯蔵安定性、均一分散性および低粘性に優れる。さらに、本発明の二次電池セパレータ用コート材原料によれば、耐熱性、透気性および密着性に優れる二次電池セパレータを得られる。 Therefore, the coating material raw material for secondary battery separators of the present invention is excellent in storage stability, uniform dispersibility and low viscosity. Furthermore, according to the coating material raw material for a secondary battery separator of the present invention, a secondary battery separator excellent in heat resistance, air permeability and adhesion can be obtained.
　本発明の二次電池セパレータ用コート材は、上記の二次電池セパレータ用コート材原料を含むため、二次電池セパレータの生産性の向上を図ることができる。さらに、本発明の二次電池セパレータ用コート材は、耐熱性、透気性および密着性に優れる二次電池セパレータを得られる。 Since the secondary battery separator coating material of the present invention contains the above-described secondary battery separator coating material raw material, productivity of the secondary battery separator can be improved. Furthermore, the coating material for a secondary battery separator of the present invention can provide a secondary battery separator that is excellent in heat resistance, air permeability and adhesion.
　本発明の二次電池セパレータは、上記の二次電池セパレータ用コート材の塗布膜を備えるため、生産性、耐熱性、透気性および密着性に優れる。 Since the secondary battery separator of the present invention includes the coating film of the secondary battery separator coating material, it is excellent in productivity, heat resistance, air permeability and adhesion.
　本発明の二次電池セパレータの製造方法によれば、耐熱性、透気性および密着性に優れる二次電池セパレータを、効率よく製造できる。 According to the method for manufacturing a secondary battery separator of the present invention, a secondary battery separator excellent in heat resistance, air permeability and adhesion can be efficiently manufactured.
　本発明の二次電池は、上記の二次電池セパレータを備えているため、生産性、耐熱性、透気性および密着性に優れる。その結果、本発明の二次電池は、生産性、耐熱性、透気性および密着性に優れる。 Since the secondary battery of the present invention includes the secondary battery separator described above, it is excellent in productivity, heat resistance, air permeability, and adhesion. As a result, the secondary battery of the present invention is excellent in productivity, heat resistance, air permeability and adhesion.
　本発明の二次電池セパレータ用コート材原料は、水溶性ポリマーと非水溶性ポリマーとの複合ポリマーを含んでいる。複合ポリマーは、水溶性ポリマーと非水溶性ポリマーとを含み、水溶性ポリマーと非水溶性ポリマーとは化学結合している。すなわち、水溶性ポリマーと非水溶性ポリマーとが化学結合することによって、複合ポリマーが形成されている。 The coating material raw material for secondary battery separators of the present invention contains a composite polymer of a water-soluble polymer and a water-insoluble polymer. A composite polymer includes a water-soluble polymer and a water-insoluble polymer, and the water-soluble polymer and the water-insoluble polymer are chemically bonded. That is, a composite polymer is formed by chemically bonding a water-soluble polymer and a water-insoluble polymer.
　水溶性ポリマーは、二次電池セパレータ用コート材原料の水に対する溶解性を向上させるポリマーである。水溶性ポリマーは、比較的親水性であり、水溶性ポリマーのＳＰ値（溶解度パラメータ）は、１３．０（ｃａｌ／ｃｍ３）１／２以上である。 The water-soluble polymer is a polymer that improves the solubility in water of the coating material raw material for the secondary battery separator. The water-soluble polymer is relatively hydrophilic, and the SP value (solubility parameter) of the water-soluble polymer is 13.0 (cal/cm 3 ) 1/2 or more.
　なお、ＳＰ値は、Ｍｉｌｌｉｏｎ　Ｚｉｌｌｉｏｎ　Ｓｏｆｔｗａｒｅ社の計算ソフトＣＨＥＯＰＳ（ｖｅｒｓｉｏｎ４．０）にて算出できる。また、該計算ソフトで用いられる計算手法は、Ｃｏｍｐｕｔａｔｉｏｎａｌ　Ｍａｔｅｒｉａｌｓ　Ｓｃｉｅｎｃｅ　ｏｆ　Ｐｏｌｙｍｅｒｓ（Ａ．Ａ．Ａｓｋａｄｓｋｉｉ、　Ｃａｍｂｒｉｄｇｅ　Ｉｎｔｌ　Ｓｃｉｅｎｃｅ　Ｐｕｂ　（２００５／１２／３０））Ｃｈａｐｔｅｒ　ＸＩＩに記載されている（以下同様）。 The SP value can be calculated using Million Zillion Software's calculation software CHEOPS (version 4.0). In addition, the calculation method used in the calculation software is described in Computational Materials Science of Polymers (AA Askadskii, Cambridge Intl Science Pub (2005/12/30)) Chapter XII (same below).
　水溶性ポリマーのＳＰ値（溶解度パラメータ）は、より具体的には、１３．０（ｃａｌ／ｃｍ３）１／２以上、好ましくは、１３．２（ｃａｌ／ｃｍ３）１／２以上、より好ましくは、１３．４（ｃａｌ／ｃｍ３）１／２以上である。また、水溶性ポリマーのＳＰ値（溶解度パラメータ）は、例えば、２０．０（ｃａｌ／ｃｍ３）１／２以下、好ましくは、１８．０（ｃａｌ／ｃｍ３）１／２以下、より好ましくは、１６．０（ｃａｌ／ｃｍ３）１／２以下である。 More specifically, the SP value (solubility parameter) of the water-soluble polymer is 13.0 (cal/cm 3 ) 1/2 or more, preferably 13.2 (cal/cm 3 ) 1/2 or more, and more Preferably, it is 13.4 (cal/cm 3 ) 1/2 or more. The SP value (solubility parameter) of the water-soluble polymer is, for example, 20.0 (cal/cm 3 ) 1/2 or less, preferably 18.0 (cal/cm 3 ) 1/2 or less, more preferably , 16.0 (cal/cm 3 ) 1/2 or less.
　水溶性ポリマーは、第１反応性官能基を含んでいる。第１反応性官能基は、非水溶性ポリマー（後述）の第２反応性官能基（後述）に化学結合するための官能基である。第１反応性官能基としては、例えば、カルボキシ基、水酸基、グリシジル基、イソシアネート基およびリン酸基が挙げられる。複合ポリマーの生産容易性の観点から、第１反応性官能基として、好ましくは、カルボキシ基が挙げられる。 The water-soluble polymer contains a first reactive functional group. The first reactive functional group is a functional group for chemically bonding to a second reactive functional group (described later) of a water-insoluble polymer (described later). Examples of the first reactive functional groups include carboxy groups, hydroxyl groups, glycidyl groups, isocyanate groups and phosphoric acid groups. From the viewpoint of ease of production of the composite polymer, the first reactive functional group is preferably a carboxy group.
　水溶性ポリマーは、水溶性ポリマー原料（モノマー組成物）を、公知の方法で重合することにより得られる。水溶性ポリマー原料は、水溶性ポリマーのＳＰ値が上記範囲となり、かつ、上記の第１反応性官能基が水溶性ポリマーに含まれるように、適宜選択される。 A water-soluble polymer is obtained by polymerizing a water-soluble polymer raw material (monomer composition) by a known method. The water-soluble polymer raw material is appropriately selected so that the SP value of the water-soluble polymer is within the above range and the first reactive functional group is contained in the water-soluble polymer.
　より具体的には、水溶性ポリマー原料は、例えば、（メタ）アクリルアミドと、第１反応性官能基含有モノマーとを含有する。なお、（メタ）アクリルとは、アクリルおよび／またはメタクリルを示す（以下同様）。 More specifically, the water-soluble polymer raw material contains, for example, (meth)acrylamide and a monomer containing a first reactive functional group. In addition, (meth)acryl means acryl and/or methacryl (the same shall apply hereinafter).
　水溶性ポリマー原料が、（メタ）アクリルアミドを含んでいれば、水溶性ポリマーは、（メタ）アクリルアミドに由来する繰り返し単位を有するため、水溶性（ＳＰ値）を良好に調整できる。 If the water-soluble polymer raw material contains (meth)acrylamide, the water-solubility (SP value) can be well adjusted because the water-soluble polymer has repeating units derived from (meth)acrylamide.
　（メタ）アクリルアミドとしては、アクリルアミドおよびメタクリルアミドが挙げられ、好ましくは、メタクリルアミドが挙げられる。 (Meth)acrylamide includes acrylamide and methacrylamide, preferably methacrylamide.
　第１反応性官能基含有モノマーは、上記した第１反応性官能基と、エチレン性二重結合とを含有するモノマーである。第１反応性官能基含有モノマーとしては、例えば、カルボキシ基含有ビニルモノマー、水酸基含有ビニルモノマー、グリシジル基含有ビニルモノマー、イソシアネート基含有ビニルモノマーおよびリン酸基含有ビニルモノマーが挙げられる。 The first reactive functional group-containing monomer is a monomer containing the above-described first reactive functional group and an ethylenic double bond. Examples of the first reactive functional group-containing monomer include carboxy group-containing vinyl monomers, hydroxyl group-containing vinyl monomers, glycidyl group-containing vinyl monomers, isocyanate group-containing vinyl monomers, and phosphoric acid group-containing vinyl monomers.
　カルボキシ基含有ビニルモノマーとしては、例えば、モノカルボン酸、ジカルボン酸およびこれらの塩が挙げられる。モノカルボン酸としては、例えば、（メタ）アクリル酸が挙げられる。ジカルボン酸としては、例えば、イタコン酸、マレイン酸、フマル酸、無水イタコン酸、無水マレイン酸および無水フマル酸が挙げられる。これらは、単独使用または２種類以上併用できる。 　Carboxy group-containing vinyl monomers include, for example, monocarboxylic acids, dicarboxylic acids, and salts thereof. Examples of monocarboxylic acids include (meth)acrylic acid. Dicarboxylic acids include, for example, itaconic acid, maleic acid, fumaric acid, itaconic anhydride, maleic anhydride and fumaric anhydride. These can be used alone or in combination of two or more.
　水酸基含有ビニルモノマーとしては、例えば、ヒドロキシメチル（メタ）アクリレート、２－ヒドロキシエチル（メタ）アクリレート、３－ヒドロキシプロピル（メタ）アクリレート、１－メチル－２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、および、４－ヒドロキシブチル（メタ）アクリレートが挙げられる。 Examples of hydroxyl group-containing vinyl monomers include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-methyl-2-hydroxyethyl (meth)acrylate, 2-hydroxy Propyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate can be mentioned.
　グリシジル基含有ビニルモノマーとしては、例えば、グリシジル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレートグリシジルエーテル、および、アリルグリシジルエーテルが挙げられる。 Examples of glycidyl group-containing vinyl monomers include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and allyl glycidyl ether.
　イソシアネート基含有ビニルモノマーとしては、例えば、イソシアナトメチル（メタ）アクリレート、２－イソシアナトエチル（メタ）アクリレート、３－イソシアナトプロピル（メタ）アクリレート、１－メチル－２－イソシアナトエチル（メタ）アクリレート、２－イソシアナトプロピル（メタ）アクリレート、および、４－イソシアナトブチル（メタ）アクリレートが挙げられる。 Examples of isocyanate group-containing vinyl monomers include isocyanatomethyl (meth) acrylate, 2-isocyanatoethyl (meth) acrylate, 3-isocyanatopropyl (meth) acrylate, 1-methyl-2-isocyanatoethyl (meth) acrylates, 2-isocyanatopropyl (meth)acrylate, and 4-isocyanatobutyl (meth)acrylate.
　リン酸基含有ビニルモノマーとしては、例えば、アシッドホスフォオキシエチル（メタ）アクリレート、および、モノ（２－ヒドロキシエチル（メタ）アクリレート）ホスフェートが挙げられる。 Examples of phosphate group-containing vinyl monomers include acid phosphooxyethyl (meth)acrylate and mono(2-hydroxyethyl (meth)acrylate) phosphate.
　これら第１反応性官能基含有モノマーは、単独使用または２種類以上併用できる。なお、第１反応性官能基含有モノマーが２種類以上併用される場合、第１反応性官能基含有モノマーの種類は、第１反応性官能基同士で結合しないように適宜選択される。 These first reactive functional group-containing monomers can be used alone or in combination of two or more. When two or more types of first reactive functional group-containing monomers are used in combination, the types of first reactive functional group-containing monomers are appropriately selected so that the first reactive functional groups do not bond to each other.
　第１反応性官能基含有モノマーとして、好ましくは、カルボキシ基含有ビニルモノマーが挙げられる。水溶性ポリマー原料が、カルボキシ基含有ビニルモノマーを含んでいれば、水溶性ポリマーは、カルボキシ基含有ビニルモノマーに由来する繰り返し単位を有するため、優れた水溶性を得ることができる。 A vinyl monomer containing a carboxy group is preferably used as the first reactive functional group-containing monomer. If the water-soluble polymer raw material contains a carboxyl group-containing vinyl monomer, the water-soluble polymer has repeating units derived from the carboxyl group-containing vinyl monomer, so that excellent water solubility can be obtained.
　また、水溶性ポリマー原料は、任意成分として、共重合性モノマー（以下、第１共重合性モノマーと称する。）を含有することができる。第１共重合性モノマーとしては、例えば、（メタ）アクリルアミドおよび／または第１反応性官能基含有モノマーと共重合可能なモノマーが挙げられる。 In addition, the water-soluble polymer raw material can contain a copolymerizable monomer (hereinafter referred to as a first copolymerizable monomer) as an optional component. Examples of the first copolymerizable monomer include monomers copolymerizable with (meth)acrylamide and/or the first reactive functional group-containing monomer.
　第１共重合性モノマーとしては、例えば、（メタ）アクリル酸アルキルエステルが挙げられる。（メタ）アクリル酸アルキルエステルとしては、例えば、炭素数１～２０のアルキル部分を有するアルキル（メタ）アクリレートが挙げられる。そのようなアルキル（メタ）アクリレートとしては、例えば、メチル（メタ）アクリレート、エチル（メタ）アクリレート、イソプロピル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート、イソブチル（メタ）アクリレート、ｓ－ブチル（メタ）アクリレート、ｔ－ブチル（メタ）アクリレート、ｎ－アミル（メタ）アクリレート、イソアミル（メタ）アクリレート、ｎ－ヘキシル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、オクチル（メタ）アクリレート、デシル（メタ）アクリレート、ドデシル（メタ）アクリレート、および、オクタデシル（メタ）アクリレートが挙げられる。これらは、単独使用または２種類以上併用できる。 Examples of the first copolymerizable monomer include (meth)acrylic acid alkyl esters. (Meth)acrylic acid alkyl esters include, for example, alkyl (meth)acrylates having an alkyl portion having 1 to 20 carbon atoms. Examples of such alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, ) acrylate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate ) acrylate, dodecyl (meth)acrylate, and octadecyl (meth)acrylate. These can be used alone or in combination of two or more.
　また、第１共重合性モノマーとしては、例えば、３級アミノ基含有ビニルモノマー、４級アンモニウム基含有ビニルモノマー、シアノ基含有ビニルモノマー、スルホン酸基含有ビニルモノマー、および、アセトアセトキシ基含有ビニルモノマーが挙げられる。 Examples of the first copolymerizable monomer include a tertiary amino group-containing vinyl monomer, a quaternary ammonium group-containing vinyl monomer, a cyano group-containing vinyl monomer, a sulfonic acid group-containing vinyl monomer, and an acetoacetoxy group-containing vinyl monomer. is mentioned.
　３級アミノ基含有ビニルモノマーとしては、例えば、Ｎ，Ｎ－ジアルキルアミノアルキル（メタ）アクリレート、および、Ｎ，Ｎ－ジアルキルアミノアルキル（メタ）アクリルアミドが挙げられる。Ｎ，Ｎ－ジアルキルアミノアルキル（メタ）アクリレートとしては、例えば、Ｎ，Ｎ－ジメチルアミノエチル（メタ）アクリレート、Ｎ，Ｎ－ジエチルアミノエチル（メタ）アクリレート、Ｎ，Ｎ－ジメチルアミノプロピル（メタ）アクリレート、Ｎ，Ｎ－ジ－ｔ－ブチルアミノエチル（メタ）アクリレート、および、Ｎ，Ｎ－ジメチルアミノブチル（メタ）アクリレートが挙げられる。Ｎ，Ｎ－ジアルキルアミノアルキル（メタ）アクリルアミドとしては、例えば、Ｎ，Ｎ－ジメチルアミノエチル（メタ）アクリルアミド、Ｎ，Ｎ－ジエチルアミノエチル（メタ）アクリルアミド、および、Ｎ，Ｎ－ジメチルアミノプロピル（メタ）アクリルアミドが挙げられる。 Examples of tertiary amino group-containing vinyl monomers include N,N-dialkylaminoalkyl(meth)acrylates and N,N-dialkylaminoalkyl(meth)acrylamides. Examples of N,N-dialkylaminoalkyl (meth)acrylates include N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate. , N,N-di-t-butylaminoethyl (meth)acrylate, and N,N-dimethylaminobutyl (meth)acrylate. Examples of N,N-dialkylaminoalkyl (meth)acrylamides include N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, and N,N-dimethylaminopropyl (meth)acrylamide. ) acrylamide.
　４級アンモニウム基含有ビニルモノマーとしては、例えば、上記３級アミノ基含有モノマーに４級化剤を作用させた４級化物が挙げられる。４級化剤としては、例えば、エピハロヒドリン、ハロゲン化ベンジルおよびハロゲン化アルキルが挙げられる。 Examples of quaternary ammonium group-containing vinyl monomers include quaternized products obtained by reacting the above-mentioned tertiary amino group-containing monomers with a quaternizing agent. Quaternizing agents include, for example, epihalohydrins, benzyl halides and alkyl halides.
　シアノ基含有ビニルモノマーとしては、例えば、（メタ）アクリロニトリルが挙げられる。 Examples of cyano group-containing vinyl monomers include (meth)acrylonitrile.
　スルホン酸基含有ビニルモノマーとしては、例えば、アリルスルホン酸、メタリルスルホン酸、および、アクリルアミドｔ－ブチルスルホン酸が挙げられる。また、スルホン酸基含有ビニルモノマーとしては、塩も挙げられる。塩としては、例えば、ナトリウム塩、カリウム塩およびアンモニウム塩が挙げられる。スルホン酸基含有モノマーの塩として、より具体的には、例えば、アリルスルホン酸ナトリウム、メタリルスルホン酸ナトリウム、および、メタリルスルホン酸アンモニウムが挙げられる。 Examples of sulfonic acid group-containing vinyl monomers include allylsulfonic acid, methallylsulfonic acid, and acrylamido-t-butylsulfonic acid. Moreover, a salt is also mentioned as a sulfonic-acid-group-containing vinyl monomer. Salts include, for example, sodium, potassium and ammonium salts. More specific examples of salts of sulfonic acid group-containing monomers include sodium allylsulfonate, sodium methallylsulfonate, and ammonium methallylsulfonate.
　アセトアセトキシ基含有ビニルモノマーとしては、例えば、（メタ）アクリル酸アセトアセトキシエチルが挙げられる。 Examples of acetoacetoxy group-containing vinyl monomers include acetoacetoxyethyl (meth)acrylate.
　さらに、第１共重合性モノマーとしては、例えば、ビニルエステル類、芳香族ビニルモノマー、不飽和カルボン酸アミド（（メタ）アクリルアミドを除く。）、複素環式ビニル化合物、ハロゲン化ビニリデン化合物、α－オレフィン類、ジエン類、および、架橋性ビニルモノマーも挙げられる。ビニルエステル類としては、例えば、酢酸ビニルおよびプロピオン酸ビニルが挙げられる。芳香族ビニルモノマーとしては、例えば、スチレン、α―メチルスチレン、ｐ－メチルスチレン、ビニルトルエンおよびクロロスチレンが挙げられる。不飽和カルボン酸アミドとしては、例えば、Ｎ－メチロール（メタ）アクリルアミドが挙げられる。複素環式ビニル化合物としては、例えば、ビニルピロリドンが挙げられる。ハロゲン化ビニリデン化合物としては、例えば、塩化ビニリデンおよびフッ化ビニリデンが挙げられる。α－オレフィン類としては、例えば、エチレンおよびプロピレンが挙げられる。ジエン類としては、例えば、ブタジエンが挙げられる。架橋性ビニルモノマーとしては、例えば、メチレンビス（メタ）アクリルアミド、ジビニルベンゼン、ポリエチレングリコール鎖含有ジ（メタ）アクリレート、トリメチロールプロパンテトラアクリレート、ペンタエリストールトリアクリレートおよびペンタエリストールテトラアクリレートが挙げられる。 Furthermore, examples of the first copolymerizable monomer include vinyl esters, aromatic vinyl monomers, unsaturated carboxylic acid amides (excluding (meth)acrylamide), heterocyclic vinyl compounds, vinylidene halide compounds, α- Also included are olefins, dienes, and crosslinkable vinyl monomers. Vinyl esters include, for example, vinyl acetate and vinyl propionate. Aromatic vinyl monomers include, for example, styrene, α-methylstyrene, p-methylstyrene, vinyltoluene and chlorostyrene. Examples of unsaturated carboxylic acid amides include N-methylol(meth)acrylamide. Heterocyclic vinyl compounds include, for example, vinylpyrrolidone. Vinylidene halide compounds include, for example, vinylidene chloride and vinylidene fluoride. Alpha-olefins include, for example, ethylene and propylene. Examples of dienes include butadiene. Crosslinkable vinyl monomers include, for example, methylenebis(meth)acrylamide, divinylbenzene, polyethylene glycol chain-containing di(meth)acrylates, trimethylolpropane tetraacrylate, pentaerythritol triacrylate and pentaerythritol tetraacrylate.
　これら第１共重合性モノマーは、単独使用または２種類以上併用することができる。第１共重合性モノマーとして、耐熱性および透気性の観点から、好ましくは、３級アミノ基含有ビニルモノマーが挙げられる。 These first copolymerizable monomers can be used alone or in combination of two or more. From the viewpoint of heat resistance and air permeability, the first copolymerizable monomer is preferably a tertiary amino group-containing vinyl monomer.
　また、第１反応性官能基と第２反応性官能基との組み合わせによって、後述する第２反応性官能基と反応できない（または、反応可能であるが、反応速度などの観点からほとんど反応しない）種類の第１反応性官能基を含有する第１反応性官能基含有モノマーは、第１共重合性モノマーに分類される。水溶性の度合い（ＳＰ値）を調整する観点から、第１共重合性モノマーとして、好ましくは、第１反応性基含有モノマーとして上記した水酸基含有ビニルモノマーが挙げられる。 In addition, depending on the combination of the first reactive functional group and the second reactive functional group, it cannot react with the second reactive functional group described later (or it can react, but it hardly reacts from the viewpoint of reaction rate etc.) A first reactive functional group-containing monomer containing a first reactive functional group of the type is classified as a first copolymerizable monomer. From the viewpoint of adjusting the degree of water solubility (SP value), the first copolymerizable monomer is preferably the hydroxyl group-containing vinyl monomer described above as the first reactive group-containing monomer.
　また、好ましくは、第１共重合性モノマーは、（メタ）アクリル酸アルキルエステルを含有しない。すなわち、水溶性ポリマー原料は、好ましくは、（メタ）アクリル酸アルキルエステルを含有しない。より具体的には、（メタ）アクリル酸アルキルエステルを含有していないモノマー組成物は、好ましくは、水溶性ポリマー原料であり、後述する非水溶性ポリマー原料とは区別される。 Also, preferably, the first copolymerizable monomer does not contain a (meth)acrylic acid alkyl ester. That is, the water-soluble polymer raw material preferably does not contain a (meth)acrylic acid alkyl ester. More specifically, the monomer composition containing no (meth)acrylic acid alkyl ester is preferably a water-soluble polymer raw material, which is distinguished from the water-insoluble polymer raw material described below.
　水溶性ポリマー原料において、各モノマーの割合は、水溶性ポリマーのＳＰ値が上記範囲となり、かつ、水溶性ポリマーが上記の第１反応性官能基を含むように、適宜選択される。 In the water-soluble polymer raw material, the ratio of each monomer is appropriately selected so that the SP value of the water-soluble polymer is within the above range and the water-soluble polymer contains the above first reactive functional group.
　例えば、水溶性ポリマー原料は、（メタ）アクリルアミドおよび第１反応性官能基含有モノマーからなるか、または、（メタ）アクリルアミド、第１反応性官能基含有モノマーおよび第１共重合性モノマーからなる。 For example, the water-soluble polymer raw material consists of (meth)acrylamide and a first reactive functional group-containing monomer, or (meth)acrylamide, a first reactive functional group-containing monomer and a first copolymerizable monomer.
　水溶性ポリマー原料は、好ましくは、（メタ）アクリルアミドおよびカルボキシ基含有ビニルモノマーからなるか、または、（メタ）アクリルアミド、カルボキシ基含有ビニルモノマーおよび第１共重合性モノマーからなる。 The water-soluble polymer raw material preferably consists of (meth)acrylamide and a carboxy group-containing vinyl monomer, or (meth)acrylamide, a carboxy group-containing vinyl monomer and a first copolymerizable monomer.
　（メタ）アクリルアミドの含有割合は、優れた耐熱性を得る観点から、水溶性ポリマー原料の総量１００質量部に対して、例えば、４０質量部以上、好ましくは、５０質量部以上、より好ましくは、６０質量部以上、さらに好ましくは、７０質量部以上である。また、（メタ）アクリルアミドの含有割合は、優れた耐熱性を得る観点から、水溶性ポリマー原料の総量１００質量部に対して、例えば、９７質量部以下、好ましくは、９６質量部以下、より好ましくは、９５質量部以下である。 From the viewpoint of obtaining excellent heat resistance, the content of (meth)acrylamide is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, more preferably 50 parts by mass or more, and more preferably 60 parts by mass or more, more preferably 70 parts by mass or more. In addition, from the viewpoint of obtaining excellent heat resistance, the content of (meth)acrylamide is, for example, 97 parts by mass or less, preferably 96 parts by mass or less, more preferably 96 parts by mass or less, with respect to 100 parts by mass of the total amount of the water-soluble polymer raw material. is 95 parts by mass or less.
　また、第１反応性官能基含有モノマーの含有割合は、水溶性ポリマー原料の総量１００質量部に対して、例えば、３質量部以上、好ましくは、８質量部以上、より好ましくは、１０質量部以上である。また、第１反応性官能基含有モノマーの含有割合は、水溶性ポリマー原料の総量１００質量部に対して、例えば、６０質量部以下、好ましくは、４０質量部以下、より好ましくは、３０質量部以下、さらに好ましくは、２０質量部以下である。 In addition, the content of the first reactive functional group-containing monomer is, for example, 3 parts by mass or more, preferably 8 parts by mass or more, more preferably 10 parts by mass with respect to 100 parts by mass of the total amount of the water-soluble polymer raw material. That's it. Further, the content of the first reactive functional group-containing monomer is, for example, 60 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass with respect to 100 parts by mass of the total amount of the water-soluble polymer raw material. Below, more preferably, it is 20 mass parts or less.
　また、水溶性ポリマー原料において、第１共重合性モノマーの含有割合は、水溶性ポリマー原料の総量１００質量部に対して、例えば、４０質量部以下、好ましくは、２０質量部以下、より好ましくは、１５質量部以下であり、例えば、０質量部以上である。 In the water-soluble polymer raw material, the content of the first copolymerizable monomer is, for example, 40 parts by mass or less, preferably 20 parts by mass or less, more preferably 100 parts by mass in total of the water-soluble polymer raw material. , 15 parts by mass or less, for example, 0 parts by mass or more.
　そして、水溶性ポリマーは、上記した水溶性ポリマー原料を、後述する方法で重合することにより得られる。水溶性ポリマーにおける各モノマーに由来する繰り返し単位の含有率は、水溶性ポリマー原料中の各モノマーの含有率と、同一である。 Then, the water-soluble polymer is obtained by polymerizing the water-soluble polymer raw material described above by the method described later. The content of repeating units derived from each monomer in the water-soluble polymer is the same as the content of each monomer in the water-soluble polymer raw material.
　すなわち、（メタ）アクリルアミドに由来する繰り返し単位の含有率は、優れた耐熱性を得る観点から、水溶性ポリマーの総量に対して、例えば、４０質量％以上、好ましくは、５０質量％以上、より好ましくは、６０質量％以上、さらに好ましくは、７０質量％以上である。また、（メタ）アクリルアミドに由来する繰り返し単位の含有率は、優れた耐熱性を得る観点から、水溶性ポリマーの総量に対して、例えば、９７質量％以下、好ましくは、９６質量％以下、より好ましくは、９５質量％以下である。 That is, from the viewpoint of obtaining excellent heat resistance, the content of repeating units derived from (meth)acrylamide is, for example, 40% by mass or more, preferably 50% by mass or more, relative to the total amount of the water-soluble polymer. It is preferably 60% by mass or more, more preferably 70% by mass or more. In addition, from the viewpoint of obtaining excellent heat resistance, the content of repeating units derived from (meth)acrylamide is, for example, 97% by mass or less, preferably 96% by mass or less, or more, relative to the total amount of the water-soluble polymer. Preferably, it is 95% by mass or less.
　また、第１反応性官能基含有モノマーに由来する繰り返し単位の含有率が、水溶性ポリマーの総量に対して、例えば、３質量％以上、好ましくは、８質量％以上、より好ましくは、１０質量％以上である。また、第１反応性官能基含有モノマーに由来する繰り返し単位の含有率が、水溶性ポリマーの総量に対して、例えば、６０質量％以下、好ましくは、４０質量％以下、より好ましくは、３０質量％以下、さらに好ましくは、２０質量％以下である。 In addition, the content of the repeating unit derived from the first reactive functional group-containing monomer is, for example, 3% by mass or more, preferably 8% by mass or more, more preferably 10% by mass, relative to the total amount of the water-soluble polymer. % or more. Further, the content of repeating units derived from the first reactive functional group-containing monomer is, for example, 60% by mass or less, preferably 40% by mass or less, more preferably 30% by mass, relative to the total amount of the water-soluble polymer. % or less, more preferably 20 mass % or less.
　また、第１共重合性モノマーに由来する繰り返し単位の含有率が、水溶性ポリマーの総量に対して、例えば、４０質量％以下、好ましくは、２０質量％以下、より好ましくは、１５質量％以下であり、例えば、０質量％以上である。 In addition, the content of repeating units derived from the first copolymerizable monomer is, for example, 40% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total amount of the water-soluble polymer. and, for example, 0% by mass or more.
　水溶性ポリマーの重量平均分子量（ＧＰＣ法による標準ポリエチレングリコール／ポリエチレンオキサイド換算重量平均分子量）は、耐熱性および透気性の観点から、例えば、５千以上、好ましくは、１万以上、より好ましくは、３万以上、さらに好ましくは、５万以上である。また、水溶性ポリマーの重量平均分子量（ＧＰＣ法による標準ポリエチレングリコール／ポリエチレンオキサイド換算重量平均分子量）は、低粘性の観点から、例えば、５０万以下、好ましくは、２０万以下、より好ましくは、１５万以下、さらに好ましくは、１０万以下、とりわけ好ましくは、８万以下である。 The weight average molecular weight of the water-soluble polymer (standard polyethylene glycol/polyethylene oxide conversion weight average molecular weight by GPC method) is, from the viewpoint of heat resistance and air permeability, for example, 5,000 or more, preferably 10,000 or more, and more preferably, 30,000 or more, more preferably 50,000 or more. In addition, the weight average molecular weight of the water-soluble polymer (standard polyethylene glycol/polyethylene oxide conversion weight average molecular weight by GPC method) is, for example, 500,000 or less, preferably 200,000 or less, more preferably 15, from the viewpoint of low viscosity. 10,000 or less, more preferably 100,000 or less, and particularly preferably 80,000 or less.
　水溶性ポリマーの重量平均分子量が上記範囲であれば、とりわけ貯蔵安定性、均一分散性および低粘性の向上を図ることができる。なお、重量平均分子量の測定方法は、後述する実施例に準拠する。 If the weight-average molecular weight of the water-soluble polymer is within the above range, improvement in storage stability, uniform dispersibility and low viscosity can be achieved. The method for measuring the weight-average molecular weight conforms to the examples described later.
　また、水溶性ポリマーのガラス転移温度は、耐熱性および透気性の観点から、例えば、１００℃以上、好ましくは、１５０℃以上、より好ましくは、２００℃以上、さらに好ましくは、２１０℃以上である。また、水溶性ポリマーのガラス転移温度は、二次電池セパレータ用コート材を塗工した塗工層の柔軟性の観点から、例えば、３００℃以下、好ましくは、２４０℃以下、より好ましくは、２３０℃以下、さらに好ましくは、２２０℃以下である。 Further, from the viewpoint of heat resistance and air permeability, the glass transition temperature of the water-soluble polymer is, for example, 100° C. or higher, preferably 150° C. or higher, more preferably 200° C. or higher, and still more preferably 210° C. or higher. . Further, the glass transition temperature of the water-soluble polymer is, for example, 300° C. or lower, preferably 240° C. or lower, more preferably 230° C., from the viewpoint of the flexibility of the coating layer coated with the secondary battery separator coating material. ℃ or less, more preferably 220 ℃ or less.
　水溶性ポリマーのガラス転移温度が上記範囲であれば、とりわけ耐熱性、透気性および密着性を兼ね備える二次電池セパレータを得ることができ、さらに、貯蔵安定性、均一分散性および低粘性の向上を図ることができる。なお、ガラス転移温度は、ＦＯＸの式により算出される（以下同様）。 If the glass transition temperature of the water-soluble polymer is within the above range, it is possible to obtain a secondary battery separator having heat resistance, air permeability and adhesion, and further improve storage stability, uniform dispersibility and low viscosity. can be planned. The glass transition temperature is calculated by the FOX formula (the same applies hereinafter).
　水溶性ポリマーの比重は、例えば、１．０２以上、好ましくは、１．０５以上である。また、水溶性ポリマーの比重は、例えば、１．２０以下、好ましくは、１．１５以下である。 The specific gravity of the water-soluble polymer is, for example, 1.02 or more, preferably 1.05 or more. Also, the specific gravity of the water-soluble polymer is, for example, 1.20 or less, preferably 1.15 or less.
　非水溶性ポリマーは、二次電池セパレータ用コート材原料の密着性を向上させるポリマーである。非水溶性ポリマーは、比較的疎水性であり、非水溶性ポリマーのＳＰ値（溶解度パラメータ）は、１３．０（ｃａｌ／ｃｍ３）１／２未満である。 The water-insoluble polymer is a polymer that improves the adhesion of the coating material raw material for secondary battery separators. The water-insoluble polymer is relatively hydrophobic, and the SP value (solubility parameter) of the water-insoluble polymer is less than 13.0 (cal/cm 3 ) 1/2 .
　非水溶性ポリマーのＳＰ値（溶解度パラメータ）は、より具体的には、１３．０（ｃａｌ／ｃｍ３）１／２未満、好ましくは、１２．５（ｃａｌ／ｃｍ３）１／２以下、より好ましくは、１２．０（ｃａｌ／ｃｍ３）１／２以下、さらに好ましくは、１１．０（ｃａｌ／ｃｍ３）１／２以下である。また、非水溶性ポリマーのＳＰ値（溶解度パラメータ）は、例えば、７．０（ｃａｌ／ｃｍ３）１／２以上、好ましくは、８．０（ｃａｌ／ｃｍ３）１／２以上、より好ましくは、９．０（ｃａｌ／ｃｍ３）１／２以上である。 More specifically, the SP value (solubility parameter) of the water-insoluble polymer is less than 13.0 (cal/cm 3 ) 1/2 , preferably 12.5 (cal/cm 3 ) 1/2 or less, It is more preferably 12.0 (cal/cm 3 ) 1/2 or less, still more preferably 11.0 (cal/cm 3 ) 1/2 or less. In addition, the SP value (solubility parameter) of the water-insoluble polymer is, for example, 7.0 (cal/cm 3 ) 1/2 or more, preferably 8.0 (cal/cm 3 ) 1/2 or more, more preferably is 9.0 (cal/cm 3 ) 1/2 or more.
　非水溶性ポリマーは、第２反応性官能基を含んでいる。第２反応性官能基は、上記の水溶性ポリマーの第１反応性官能基に化学結合するための官能基である。第２反応性官能基としては、例えば、カルボキシ基、水酸基、グリシジル基、イソシアネート基およびリン酸基が挙げられる。第２反応性官能基は、第１反応性官能基の種類に応じて適宜選択される。 The water-insoluble polymer contains a second reactive functional group. The second reactive functional group is a functional group for chemically bonding to the first reactive functional group of the water-soluble polymer. Examples of second reactive functional groups include carboxy groups, hydroxyl groups, glycidyl groups, isocyanate groups and phosphoric acid groups. The second reactive functional group is appropriately selected according to the type of the first reactive functional group.
　より具体的には、例えば、第１反応性官能基がカルボキシ基を含む場合、第２反応性官能基としては、例えば、カルボキシル基に対して結合可能なグリシジル基が選択される。
　また、例えば、第１反応性官能基が水酸基を含む場合、第２反応性官能基としては、例えば、水酸基に対して結合可能なイソシアネート基が選択される。また、例えば、第１反応性官能基がグリシジル基を含む場合、第２反応性官能基としては、グリシジル基に対して結合可能なカルボキシル基および／またはリン酸基が選択される。また、例えば、第１反応性官能基がイソシアネート基を含む場合、第２反応性官能基としては、イソシアネート基に対して結合可能な水酸基が選択される。また、例えば、第１反応性官能基がリン酸基を含む、第２反応性官能基としては、リン酸基に対して結合可能なグリシジル基が選択される。複合ポリマーの生産容易性の観点から、第２反応性官能基として、好ましくは、グリシジル基が挙げられる。 More specifically, for example, when the first reactive functional group contains a carboxyl group, a glycidyl group capable of bonding to the carboxyl group is selected as the second reactive functional group.
Further, for example, when the first reactive functional group contains a hydroxyl group, an isocyanate group capable of bonding to the hydroxyl group is selected as the second reactive functional group, for example. Further, for example, when the first reactive functional group contains a glycidyl group, a carboxyl group and/or a phosphoric acid group capable of bonding to the glycidyl group are selected as the second reactive functional group. Further, for example, when the first reactive functional group contains an isocyanate group, a hydroxyl group capable of bonding to the isocyanate group is selected as the second reactive functional group. Further, for example, when the first reactive functional group contains a phosphoric acid group, a glycidyl group capable of bonding to a phosphoric acid group is selected as the second reactive functional group. From the viewpoint of ease of production of the composite polymer, the second reactive functional group is preferably a glycidyl group.
　非水溶性ポリマーは、非水溶性ポリマー原料（モノマー組成物）を、公知の方法で重合することにより得られる。水溶性ポリマー原料は、非水溶性ポリマーのＳＰ値が上記範囲となり、かつ、上記の第２反応性官能基が非水溶性ポリマーに含まれるように、適宜選択される。 A water-insoluble polymer is obtained by polymerizing a water-insoluble polymer raw material (monomer composition) by a known method. The water-soluble polymer raw material is appropriately selected so that the SP value of the water-insoluble polymer is within the above range and the second reactive functional group is contained in the water-insoluble polymer.
　より具体的には、非水溶性ポリマー原料（モノマー組成物）は、例えば、（メタ）アクリル酸アルキルエステルと、第２反応性官能基含有モノマーとを含有する。 More specifically, the water-insoluble polymer raw material (monomer composition) contains, for example, a (meth)acrylic acid alkyl ester and a monomer containing a second reactive functional group.
　非水溶性ポリマー原料が、（メタ）アクリル酸アルキルエステルを含んでいれば、非水溶性ポリマーは、（メタ）アクリル酸アルキルエステルに由来する繰り返し単位を有するため、非水溶性（ＳＰ値）を良好に調整できる。 If the water-insoluble polymer raw material contains a (meth)acrylic acid alkyl ester, the water-insoluble polymer has a repeating unit derived from the (meth)acrylic acid alkyl ester, so the water-insoluble (SP value) can be adjusted well.
　（メタ）アクリル酸アルキルエステルとしては、例えば、上記した（メタ）アクリル酸アルキルエステルが挙げられ、より具体的には、炭素数１～２０のアルキル部分を有するアルキル（メタ）アクリレートが挙げられる。これらは、単独使用または２種類以上併用できる。（メタ）アクリル酸アルキルエステルとして、好ましくは、炭素数１～４のアルキル部分を有するアルキル（メタ）アクリレートが挙げられ、より好ましくは、ｎ－ブチル（メタ）アクリレートが挙げられる。 (Meth)acrylic acid alkyl esters include, for example, the above-described (meth)acrylic acid alkyl esters, and more specifically, alkyl (meth)acrylates having an alkyl moiety having 1 to 20 carbon atoms. These can be used alone or in combination of two or more. (Meth)acrylic acid alkyl esters preferably include alkyl (meth)acrylates having an alkyl moiety of 1 to 4 carbon atoms, more preferably n-butyl (meth)acrylate.
　第２反応性官能基含有モノマーは、上記した第２反応性官能基と、エチレン性二重結合とを含有するモノマーである。第２反応性官能基含有モノマーとしては、例えば、上記したカルボキシ基含有ビニルモノマー、上記した水酸基含有ビニルモノマー、上記したグリシジル基含有ビニルモノマー、上記したイソシアネート基含有ビニルモノマーおよび上記したリン酸基含有ビニルモノマーが挙げられる。 The second reactive functional group-containing monomer is a monomer containing the above-described second reactive functional group and an ethylenic double bond. Examples of the second reactive functional group-containing monomer include the above-described carboxy group-containing vinyl monomer, the above-described hydroxyl group-containing vinyl monomer, the above-described glycidyl group-containing vinyl monomer, the above-described isocyanate group-containing vinyl monomer, and the above-described phosphoric acid group-containing monomer. Vinyl monomers are mentioned.
　これら第２反応性官能基含有モノマーは、単独使用または２種類以上併用できる。なお、第２反応性官能基含有モノマーが２種類以上併用される場合、第２反応性官能基含有モノマーの種類は、第２反応性官能基同士で結合しないように適宜選択される。 These second reactive functional group-containing monomers can be used alone or in combination of two or more. When two or more second reactive functional group-containing monomers are used in combination, the type of the second reactive functional group-containing monomer is appropriately selected so that the second reactive functional groups do not bond to each other.
　第２反応性官能基含有モノマーは、第１反応性官能基含有モノマーの種類に応じて、適宜選択される。すなわち、第１反応性官能基および第２反応性官能基が、上記した組み合わせとなるように、適宜選択される。 The second reactive functional group-containing monomer is appropriately selected according to the type of the first reactive functional group-containing monomer. That is, the first reactive functional group and the second reactive functional group are appropriately selected so as to form the above-described combination.
　より具体的には、例えば、第１反応性官能基含有モノマーがカルボキシ基含有ビニルモノマーを含む場合、第２反応性官能基としては、例えば、グリシジル基含有ビニルモノマーが選択される。また、例えば、第１反応性官能基含有モノマーが水酸基含有ビニルモノマーを含む場合、第２反応性官能基含有モノマーとしては、例えば、イソシアネート基含有ビニルモノマーが選択される。また、例えば、第１反応性官能基含有モノマーがグリシジル基含有ビニルモノマーを含む場合、第２反応性官能基含有モノマーとしては、カルボキシル基含有ビニルモノマーおよび／またはリン酸基含有ビニルモノマーが選択される。
　また、例えば、第１反応性官能基含有モノマーがイソシアネート基含有ビニルモノマーを含む場合、第２反応性官能基含有モノマーとしては、水酸基含有ビニルモノマーが選択される。また、例えば、第１反応性官能基含有モノマーがリン酸基含有ビニルモノマーを含む、第２反応性官能基含有モノマーとしては、グリシジル基含有ビニルモノマーが選択される。 More specifically, for example, when the first reactive functional group-containing monomer includes a carboxy group-containing vinyl monomer, for example, a glycidyl group-containing vinyl monomer is selected as the second reactive functional group. Further, for example, when the first reactive functional group-containing monomer includes a hydroxyl group-containing vinyl monomer, for example, an isocyanate group-containing vinyl monomer is selected as the second reactive functional group-containing monomer. Further, for example, when the first reactive functional group-containing monomer contains a glycidyl group-containing vinyl monomer, a carboxyl group-containing vinyl monomer and/or a phosphoric acid group-containing vinyl monomer are selected as the second reactive functional group-containing monomer. be.
Further, for example, when the first reactive functional group-containing monomer includes an isocyanate group-containing vinyl monomer, a hydroxyl group-containing vinyl monomer is selected as the second reactive functional group-containing monomer. Further, for example, a glycidyl group-containing vinyl monomer is selected as the second reactive functional group-containing monomer in which the first reactive functional group-containing monomer includes a phosphoric acid group-containing vinyl monomer.
　第２反応性官能基含有モノマーとして、好ましくは、グリシジル基含有ビニルモノマーが挙げられる。非水溶性ポリマー原料が、グリシジル基含有ビニルモノマーを含んでいれば、非水溶性ポリマーは、グリシジル基含有ビニルモノマーに由来する繰り返し単位を有するため、生産よく複合ポリマーが得られる。 As the second reactive functional group-containing monomer, a glycidyl group-containing vinyl monomer is preferably used. If the water-insoluble polymer raw material contains a glycidyl group-containing vinyl monomer, the water-insoluble polymer has repeating units derived from the glycidyl group-containing vinyl monomer, so that a composite polymer can be obtained with good productivity.
　また、非水溶性ポリマー原料は、任意成分として、共重合性モノマー（以下、第２共重合性モノマーと称する。）を含有することができる。第２共重合性モノマーとしては、例えば、（メタ）アクリル酸アルキルエステルおよび／または第２反応性官能基含有モノマーと共重合可能なモノマーが挙げられる。 In addition, the water-insoluble polymer raw material can contain a copolymerizable monomer (hereinafter referred to as a second copolymerizable monomer) as an optional component. Examples of the second copolymerizable monomer include monomers copolymerizable with (meth)acrylic acid alkyl esters and/or second reactive functional group-containing monomers.
　第２共重合性モノマーとしては、例えば、上記した３級アミノ基含有ビニルモノマー、上記した４級アンモニウム基含有ビニルモノマー、上記したシアノ基含有ビニルモノマー、上記したスルホン酸基含有ビニルモノマー、上記したアセトアセトキシ基含有ビニルモノマー、上記したビニルエステル類、上記した芳香族ビニルモノマー、上記した不飽和カルボン酸アミド（（メタ）アクリルアミドを含む）、上記した複素環式ビニル化合物、上記したハロゲン化ビニリデン化合物、上記したα－オレフィン類、上記したジエン類、および、上記した架橋性ビニルモノマーが挙げられる。 Examples of the second copolymerizable monomer include the above-described tertiary amino group-containing vinyl monomer, the above-described quaternary ammonium group-containing vinyl monomer, the above-described cyano group-containing vinyl monomer, the above-described sulfonic acid group-containing vinyl monomer, and the above-described Acetoacetoxy group-containing vinyl monomers, the above vinyl esters, the above aromatic vinyl monomers, the above unsaturated carboxylic acid amides (including (meth)acrylamide), the above heterocyclic vinyl compounds, the above vinylidene halide compounds , the above-described α-olefins, the above-described dienes, and the above-described crosslinkable vinyl monomers.
　これら第２共重合性モノマーは、単独使用または２種類以上併用することができる。第２共重合性モノマーとして、密着性の観点から、好ましくは、芳香族ビニルモノマーが挙げられる。 These second copolymerizable monomers can be used alone or in combination of two or more. From the viewpoint of adhesion, the second copolymerizable monomer is preferably an aromatic vinyl monomer.
　なお、第１反応性官能基と第２反応性官能基との組み合わせによって、上記した第１反性官能基と反応できない（または、反応可能であるが、反応速度などの観点からほとんど反応しない）種類の第２反応性官能基を含有する第２反応性官能基含有モノマーは、第２共重合性モノマーに分類される。非水溶性の度合い（ＳＰ値）を調整する観点から、第２共重合性モノマーとして、好ましくは、第２反応性基含有モノマーとして上記したカルボキシ基含有ビニルモノマーおよび水酸基含有ビニルモノマーが挙げられる。 In addition, depending on the combination of the first reactive functional group and the second reactive functional group, it cannot react with the above-described first antifunctional group (or it can react, but it hardly reacts from the viewpoint of reaction rate etc.) Second reactive functional group-containing monomers containing a second reactive functional group of the type are classified as second copolymerizable monomers. From the viewpoint of adjusting the degree of water insolubility (SP value), the second copolymerizable monomer preferably includes the carboxy group-containing vinyl monomer and hydroxyl group-containing vinyl monomer described above as the second reactive group-containing monomer.
　また、非水溶性ポリマー原料は、好ましくは、実質的に、シアノ基含有ビニルモノマー（具体的には、（メタ）アクリロニトリル）を含まない。実質的に、シアノ基含有ビニルモノマーを含まないとは、非水溶性ポリマー原料に対して、シアノ基含有ビニルモノマーが、例えば、２．０質量％以下、好ましくは、１．０質量％以下であることを意味する。
　シアノ基含有ビニルモノマーを配合すると、二次電池セパレータ用コート材（後述）の耐電解液性が低下する場合がある。そのため、非水溶性ポリマー原料は、好ましくは、シアノ基含有ビニルモノマーを含まない。 Also, the water-insoluble polymer raw material preferably does not substantially contain a cyano group-containing vinyl monomer (specifically, (meth)acrylonitrile). Substantially containing no cyano group-containing vinyl monomer means that the cyano group-containing vinyl monomer is, for example, 2.0% by mass or less, preferably 1.0% by mass or less, relative to the water-insoluble polymer raw material. It means that there is
When a cyano group-containing vinyl monomer is blended, the electrolytic solution resistance of the secondary battery separator coating material (described later) may be lowered. Therefore, the water-insoluble polymer raw material preferably does not contain a cyano group-containing vinyl monomer.
　非水溶性ポリマー原料において、各モノマーの割合は、非水溶性ポリマーのＳＰ値が上記範囲となり、かつ、非水溶性ポリマーが上記の第２反応性官能基を含むように、適宜選択される。 In the water-insoluble polymer raw material, the ratio of each monomer is appropriately selected so that the SP value of the water-insoluble polymer is within the above range and the water-insoluble polymer contains the above second reactive functional group.
　例えば、非水溶性ポリマー原料は、（メタ）アクリル酸アルキルエステルおよび第２反応性官能基含有モノマーからなるか、または、（メタ）アクリル酸アルキルエステル、第２反応性官能基含有モノマーおよび第２共重合性モノマーからなる。 For example, the water-insoluble polymer raw material consists of a (meth)acrylic acid alkyl ester and a second reactive functional group-containing monomer, or alternatively, a (meth)acrylic acid alkyl ester, a second reactive functional group-containing monomer and a second It consists of copolymerizable monomers.
　非水溶性ポリマー原料は、好ましくは、（メタ）アクリル酸アルキルエステルおよびグリシジル基含有ビニルモノマーからなるか、または、（メタ）アクリル酸アルキルエステル、グリシジル基含有ビニルモノマーおよび第２共重合性モノマーからなる。 The water-insoluble polymer raw material preferably consists of a (meth)acrylic acid alkyl ester and a glycidyl group-containing vinyl monomer, or from a (meth)acrylic acid alkyl ester, a glycidyl group-containing vinyl monomer and a second copolymerizable monomer. Become.
　例えば、（メタ）アクリル酸アルキルエステルの含有割合は、優れた密着性を得る観点から、非水溶性ポリマー原料１００質量部に対して、例えば、２０質量部以上、好ましくは、３０質量部以上である。また、（メタ）アクリル酸アルキルエステルの含有割合は、優れた密着性を得る観点から、非水溶性ポリマー原料１００質量部に対して、例えば、９９質量部以下、好ましくは、９０質量部以下、より好ましくは、８０質量部以下、さらに好ましくは、７０質量部以下である。 For example, the content of the (meth)acrylic acid alkyl ester is, for example, 20 parts by mass or more, preferably 30 parts by mass or more with respect to 100 parts by mass of the water-insoluble polymer raw material, from the viewpoint of obtaining excellent adhesion. be. In addition, from the viewpoint of obtaining excellent adhesion, the content of the (meth)acrylic acid alkyl ester is, for example, 99 parts by mass or less, preferably 90 parts by mass or less, with respect to 100 parts by mass of the water-insoluble polymer raw material. More preferably, it is 80 parts by mass or less, and still more preferably 70 parts by mass or less.
　また、第２反応性官能基含有モノマーの含有割合（総量）は、非水溶性ポリマー原料１００質量部に対して、例えば、１質量部以上、好ましくは、２質量部以上、より好ましくは、３質量部以上、さらに好ましくは、４質量部以上である。また、第２反応性官能基含有モノマーの含有割合（総量）は、非水溶性ポリマー原料１００質量部に対して、例えば、３０質量部以下、好ましくは、２０質量部以下、より好ましくは、１０質量部以下である。 In addition, the content ratio (total amount) of the second reactive functional group-containing monomer is, for example, 1 part by mass or more, preferably 2 parts by mass or more, more preferably 3 parts by mass with respect to 100 parts by mass of the water-insoluble polymer raw material. It is at least 4 parts by mass, more preferably at least 4 parts by mass. In addition, the content ratio (total amount) of the second reactive functional group-containing monomer is, for example, 30 parts by mass or less, preferably 20 parts by mass or less, more preferably 10 parts by mass or less with respect to 100 parts by mass of the water-insoluble polymer raw material. Part by mass or less.
　また、非水溶性ポリマー原料において、第２共重合性モノマーの含有割合は、非水溶性ポリマー原料の総量１００質量部に対して、例えば、０質量部以上、好ましくは、１０質量部以上、より好ましくは、２０質量部以上、さらに好ましくは、３０質量部以上である。また、非水溶性ポリマー原料において、第２共重合性モノマーの含有割合は、非水溶性ポリマー原料の総量１００質量部に対して、例えば、８０質量部以下、好ましくは、７０質量部以下である。 In addition, in the water-insoluble polymer raw material, the content of the second copolymerizable monomer is, for example, 0 parts by mass or more, preferably 10 parts by mass or more, with respect to the total amount of 100 parts by mass of the water-insoluble polymer raw material. Preferably, it is 20 parts by mass or more, more preferably 30 parts by mass or more. In the water-insoluble polymer raw material, the content of the second copolymerizable monomer is, for example, 80 parts by mass or less, preferably 70 parts by mass or less, with respect to 100 parts by mass of the total water-insoluble polymer raw material. .
　そして、非水溶性ポリマーは、上記した非水溶性ポリマー原料を、後述する方法で重合することにより得られる。非水溶性ポリマーにおける各モノマーに由来する繰り返し単位の含有率は、非水溶性ポリマー原料中の各モノマーの含有率と、同一である。 Then, the water-insoluble polymer is obtained by polymerizing the water-insoluble polymer raw material described above by the method described later. The content of repeating units derived from each monomer in the water-insoluble polymer is the same as the content of each monomer in the water-insoluble polymer raw material.
　すなわち、（メタ）アクリル酸アルキルエステルに由来する繰り返し単位の含有率は、非水溶性ポリマーの総量に対して、優れた密着性を得る観点から、例えば、２０質量％以上、好ましくは、４０質量％以上である。また、（メタ）アクリル酸アルキルエステルに由来する繰り返し単位の含有率は、非水溶性ポリマーの総量に対して、例えば、９９質量％以下、好ましくは、９０質量％以下、より好ましくは、８０質量％以下、さらに好ましくは、７０質量％以下である。 That is, the content of the repeating unit derived from the (meth)acrylic acid alkyl ester is, for example, 20% by mass or more, preferably 40% by mass, with respect to the total amount of the water-insoluble polymer, from the viewpoint of obtaining excellent adhesion. % or more. Further, the content of repeating units derived from (meth)acrylic acid alkyl ester is, for example, 99% by mass or less, preferably 90% by mass or less, more preferably 80% by mass, relative to the total amount of the water-insoluble polymer. % or less, more preferably 70 mass % or less.
　また、第２反応性官能基含有モノマーに由来する繰り返し単位の含有率は、非水溶性ポリマーの総量に対して、例えば、１質量％以上、好ましくは、２質量％以上、より好ましくは、３質量％以上、さらに好ましくは、４質量％以上である。また、第２反応性官能基含有モノマーに由来する繰り返し単位の含有率は、非水溶性ポリマーの総量に対して、例えば、例えば、３０質量％以下、好ましくは、２０質量％以下、より好ましくは、１０質量部以下である。 In addition, the content of the repeating unit derived from the second reactive functional group-containing monomer is, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass, relative to the total amount of the water-insoluble polymer. It is at least 4% by mass, more preferably at least 4% by mass. In addition, the content of repeating units derived from the second reactive functional group-containing monomer is, for example, 30% by mass or less, preferably 20% by mass or less, more preferably 20% by mass or less, relative to the total amount of the water-insoluble polymer. , 10 parts by mass or less.
　また、第１共重合性モノマーに由来する繰り返し単位の含有率は、非水溶性ポリマーの総量に対して、例えば、０質量％以上、好ましくは、１０質量％以上、より好ましくは、２０質量％以上、さらに好ましくは、３０質量％以上であり、例えば、７０質量％以下である。 Further, the content of the repeating unit derived from the first copolymerizable monomer is, for example, 0% by mass or more, preferably 10% by mass or more, more preferably 20% by mass, relative to the total amount of the water-insoluble polymer. More preferably, it is 30% by mass or more and, for example, 70% by mass or less.
　また、第２共重合性モノマーに由来する繰り返し単位の含有率は、非水溶性ポリマーの総量に対して、例えば、０質量％以上、好ましくは、１０質量％以上、より好ましくは、２０質量％以上、さらに好ましくは、３０質量％以上である。また、第２共重合性モノマーに由来する繰り返し単位の含有率は、非水溶性ポリマーの総量に対して、例えば、８０質量％以下、好ましくは、７０質量％以下である。 In addition, the content of repeating units derived from the second copolymerizable monomer is, for example, 0% by mass or more, preferably 10% by mass or more, more preferably 20% by mass, relative to the total amount of the water-insoluble polymer. Above, more preferably 30% by mass or more. In addition, the content of repeating units derived from the second copolymerizable monomer is, for example, 80% by mass or less, preferably 70% by mass or less, relative to the total amount of the water-insoluble polymer.
　非水溶性ポリマーのガラス転移温度は、透気性および密着性の観点から、例えば、－６０℃以上、好ましくは、－４０℃以上、より好ましくは、－２０℃以上、さらに好ましくは、０℃以上である。また、非水溶性ポリマーのガラス転移温度は、低粘性および密着性の観点から、例えば、７０℃以下、好ましくは、５０℃以下、より好ましくは、３０℃以下、さらに好ましくは、１０℃以下である。 The glass transition temperature of the water-insoluble polymer is, from the viewpoint of air permeability and adhesion, for example, −60° C. or higher, preferably −40° C. or higher, more preferably −20° C. or higher, further preferably 0° C. or higher. is. Further, the glass transition temperature of the water-insoluble polymer is, from the viewpoint of low viscosity and adhesion, for example, 70° C. or lower, preferably 50° C. or lower, more preferably 30° C. or lower, and still more preferably 10° C. or lower. be.
　非水溶性ポリマーのガラス転移温度が上記範囲であれば、とりわけ耐熱性、透気性および密着性を兼ね備える二次電池セパレータを得ることができ、さらに、貯蔵安定性、均一分散性および低粘性の向上を図ることができる。 If the glass transition temperature of the water-insoluble polymer is within the above range, it is possible to obtain a secondary battery separator having heat resistance, air permeability, and adhesion, and further improve storage stability, uniform dispersibility, and low viscosity. can be achieved.
　非水溶性ポリマーの比重は、例えば、０．８５以上、好ましくは、０．８９以上である。また、非水溶性ポリマーの比重は、例えば、０．９８以下、好ましくは、０．９５以下である。 The specific gravity of the water-insoluble polymer is, for example, 0.85 or more, preferably 0.89 or more. Moreover, the specific gravity of the water-insoluble polymer is, for example, 0.98 or less, preferably 0.95 or less.
　水溶性ポリマーの比重と非水溶性ポリマーの比重との差は、例えば、０．０４以上、好ましくは、０．１０以上である。また、水溶性ポリマーの比重と非水溶性ポリマーの比重との差は、例えば、０．３５以下、好ましくは、０．２５以下である。 The difference between the specific gravity of the water-soluble polymer and the specific gravity of the water-insoluble polymer is, for example, 0.04 or more, preferably 0.10 or more. Also, the difference between the specific gravity of the water-soluble polymer and the specific gravity of the water-insoluble polymer is, for example, 0.35 or less, preferably 0.25 or less.
　次に、複合ポリマーおよび二次電池セパレータ用コート材原料を製造する方法について、説明する。 Next, the method of manufacturing the composite polymer and the coating material raw material for the secondary battery separator will be explained.
　具体的には、複合ポリマーおよび二次電池セパレータ用コート材原料の製造方法として、例えば、第１方法および第２方法が挙げられる。第１方法では、例えば、水溶性ポリマー原料を重合し、水溶性ポリマーを得た後に、水溶性ポリマー存在下で、非水溶性ポリマー原料を重合する。第２方法では、まず、非水溶性ポリマー原料を重合し、非水溶性ポリマーを得た後に、非水溶性ポリマー存在下で、水溶性ポリマー原料を重合する。好ましくは、第１方法が挙げられる。 Specifically, methods for producing the composite polymer and the coating material raw material for the secondary battery separator include, for example, the first method and the second method. In the first method, for example, a water-soluble polymer raw material is polymerized to obtain a water-soluble polymer, and then a water-insoluble polymer raw material is polymerized in the presence of the water-soluble polymer. In the second method, first, a water-insoluble polymer raw material is polymerized to obtain a water-insoluble polymer, and then the water-soluble polymer raw material is polymerized in the presence of the water-insoluble polymer. The first method is preferred.
　第１方法は、水溶性ポリマー原料を重合してなる水溶性ポリマーを得る工程（第１工程）と、水溶性ポリマーの存在下で、非水溶性ポリマー原料を重合してなる水溶性ポリマーを得るとともに、第１反応性官能基の少なくとも一部と第２反応性官能基の少なくとも一部とを化学結合させる工程（第２工程）とを備えている。 The first method comprises a step of obtaining a water-soluble polymer by polymerizing a water-soluble polymer raw material (first step), and obtaining a water-soluble polymer by polymerizing a water-insoluble polymer raw material in the presence of the water-soluble polymer. and a step of chemically bonding at least part of the first reactive functional group and at least part of the second reactive functional group (second step).
　より具体的には、第１工程では、まず、水溶性ポリマー原料を重合させ、水溶性ポリマーを得る。水溶性ポリマーの合成では、水に、公知の重合開始剤を配合し、水中に水溶性ポリマー原料を滴下して、水溶性ポリマー原料を重合させる。また、水溶性ポリマーの重合においては、製造安定性の向上を図る観点から、必要に応じて、公知の乳化剤（界面活性剤）を配合できる。 More specifically, in the first step, first, a water-soluble polymer raw material is polymerized to obtain a water-soluble polymer. In the synthesis of the water-soluble polymer, water is blended with a known polymerization initiator, and the water-soluble polymer raw material is dropped into the water to polymerize the water-soluble polymer raw material. Moreover, in the polymerization of the water-soluble polymer, a known emulsifier (surfactant) can be blended, if necessary, from the viewpoint of improving production stability.
　重合条件は、水溶性ポリマー原料の種類に応じて、適宜設定される。例えば、常圧下において、重合温度が、例えば、３０℃以上、好ましくは、５０℃以上である。また、重合温度が、例えば、９５℃以下、好ましくは、８５℃以下である。また、重合時間が、例えば、１時間以上、好ましくは、２時間以上である。また、重合時間が、例えば、３０時間以下、好ましくは、２０時間以下である。 The polymerization conditions are appropriately set according to the type of water-soluble polymer raw material. For example, under normal pressure, the polymerization temperature is, for example, 30° C. or higher, preferably 50° C. or higher. Also, the polymerization temperature is, for example, 95° C. or lower, preferably 85° C. or lower. Also, the polymerization time is, for example, 1 hour or more, preferably 2 hours or more. Also, the polymerization time is, for example, 30 hours or less, preferably 20 hours or less.
　また、非水溶性ポリマーの重合においては、製造安定性の向上を図る観点から、例えば、公知の添加剤を、適宜の割合で配合できる。添加剤としては、例えば、ｐＨ調整剤、金属イオン封止剤、分子量調節剤（連鎖移動剤）が挙げられる。 In addition, in the polymerization of the water-insoluble polymer, for example, known additives can be blended in an appropriate proportion from the viewpoint of improving production stability. Additives include, for example, pH adjusters, metal ion sequestrants, and molecular weight adjusters (chain transfer agents).
　これにより、水溶性ポリマー原料が重合され、水溶性ポリマーが得られる。水溶性ポリマーは、第１反応性官能基含有モノマーに由来する繰り返し単位を有する。すなわち、水溶性ポリマーは、分子中に、第１反応性官能基を含んでいる。 As a result, the water-soluble polymer raw material is polymerized to obtain a water-soluble polymer. The water-soluble polymer has repeating units derived from the first reactive functional group-containing monomer. That is, the water-soluble polymer contains a first reactive functional group in its molecule.
　また、水溶性ポリマーは、水に溶解された水溶液として得られる。水溶液において、水溶性ポリマーの固形分濃度は、目的および用途に応じて、適宜設定される。 In addition, the water-soluble polymer is obtained as an aqueous solution dissolved in water. In the aqueous solution, the solid content concentration of the water-soluble polymer is appropriately set according to the purpose and application.
　次いで、第２工程では、水溶性ポリマー存在下で、非水溶性ポリマー原料を重合する。より具体的には、非水溶性ポリマー原料を水中に乳化させ、その乳化液を、上記の水溶性ポリマーの水溶液に添加し、非水溶性ポリマー原料を重合させる。 Then, in the second step, the water-insoluble polymer raw material is polymerized in the presence of the water-soluble polymer. More specifically, the water-insoluble polymer raw material is emulsified in water, and the emulsion is added to the aqueous solution of the water-soluble polymer to polymerize the water-insoluble polymer raw material.
　重合条件は、非水溶性ポリマー原料の種類に応じて、適宜設定される。例えば、常圧下において、重合温度が、例えば、３０℃以上、好ましくは、５０℃以上である。また、重合温度が、例えば、９５℃以下、好ましくは、８５℃以下である。また、重合時間が、例えば、０．５時間以上、好ましくは、１．５時間以上である。また、重合時間が、例えば、２０時間以下、好ましくは、１０時間以下である。 The polymerization conditions are appropriately set according to the type of water-insoluble polymer raw material. For example, under normal pressure, the polymerization temperature is, for example, 30° C. or higher, preferably 50° C. or higher. Also, the polymerization temperature is, for example, 95° C. or lower, preferably 85° C. or lower. Also, the polymerization time is, for example, 0.5 hours or longer, preferably 1.5 hours or longer. Also, the polymerization time is, for example, 20 hours or less, preferably 10 hours or less.
　これにより、非水溶性ポリマー原料が重合され、非水溶性ポリマーが得られる。非水溶性ポリマーは、第２反応性官能基含有モノマーに由来する繰り返し単位を有する。すなわち、非水溶性ポリマーは、分子中に、第２反応性官能基を含んでいる。 As a result, the water-insoluble polymer raw material is polymerized to obtain a water-insoluble polymer. The water-insoluble polymer has repeating units derived from the second reactive functional group-containing monomer. That is, the water-insoluble polymer contains a second reactive functional group in its molecule.
　そして、この方法では、非水溶性ポリマーの生成とともに、非水溶性ポリマー中の第２反応性官能基の少なくとも一部が、水溶性ポリマー中の第１反応性官能基の少なくとも一部と、化学結合する。 Then, in this method, at least a portion of the second reactive functional groups in the water-insoluble polymer are combined with at least a portion of the first reactive functional groups in the water-soluble polymer along with the formation of the water-insoluble polymer. Join.
　より具体的には、例えば、第１反応性官能基がカルボキシ基を含む場合、そのカルボキシ基は、第２反応性官能基としてのグリシジル基と化学結合する。また、例えば、第１反応性官能基が水酸基を含む場合、その水酸基は、第２反応性官能基としてのイソシアネート基と化学結合する。また、例えば、第１反応性官能基がグリシジル基を含む場合、そのグリシジル基は、第２反応性官能基としてのカルボキシル基および／またはリン酸基と化学結合する。また、例えば、第１反応性官能基がイソシアネート基を含む場合、そのイソシアネート基は、第２反応性官能基としての水酸基と化学結合する。また、例えば、第１反応性官能基がリン酸基を含む、そのリン酸基は、第２反応性官能基としてのグリシジル基と化学結合する。 More specifically, for example, when the first reactive functional group contains a carboxy group, the carboxy group chemically bonds with the glycidyl group as the second reactive functional group. Also, for example, when the first reactive functional group contains a hydroxyl group, the hydroxyl group chemically bonds with the isocyanate group as the second reactive functional group. Also, for example, when the first reactive functional group contains a glycidyl group, the glycidyl group chemically bonds with the carboxyl group and/or the phosphoric acid group as the second reactive functional group. Also, for example, when the first reactive functional group contains an isocyanate group, the isocyanate group chemically bonds with the hydroxyl group as the second reactive functional group. Also, for example, the first reactive functional group includes a phosphate group, and the phosphate group is chemically bonded to the glycidyl group as the second reactive functional group.
　なお、これらの反応条件は、第１反応性官能基の種類、および、第２反応性官能基の種類に応じて適宜設定される。第１反応性官能基および第２反応性官能基の反応は、通常、第２工程における非水溶性ポリマーの合成と同時に進行する。 These reaction conditions are appropriately set according to the type of the first reactive functional group and the type of the second reactive functional group. The reaction of the first reactive functional group and the second reactive functional group usually proceeds simultaneously with the synthesis of the water-insoluble polymer in the second step.
　その結果、水溶性ポリマーと非水溶性ポリマーとを化学結合させることができ、水溶性ポリマーと非水溶性ポリマーとの複合ポリマーが得られる。これにより、複合ポリマーを含む分散液（二次電池セパレータ用コート材原料）が得られる。 As a result, the water-soluble polymer and the water-insoluble polymer can be chemically bonded to obtain a composite polymer of the water-soluble polymer and the water-insoluble polymer. As a result, a dispersion containing the composite polymer (coating material raw material for secondary battery separator) is obtained.
　この分散液において、二次電池セパレータ用コート材原料の含有量（分散液の固形分濃度）は、例えば、５質量％以上であり、また、例えば、５０質量％以下である。 In this dispersion, the content of the coating material raw material for the secondary battery separator (the solid content concentration of the dispersion) is, for example, 5% by mass or more and, for example, 50% by mass or less.
　このような二次電池セパレータ用コート材原料において、非水溶性ポリマーの質量に対する、水溶性ポリマーの質量の比率は、目的および用途に応じて、適宜設定される。例えば、水溶性ポリマーおよび非水溶性ポリマーの総量１００質量部に対して、水溶性ポリマーが、耐熱性の観点から、例えば、４０質量部以上、好ましくは、５０質量部以上、より好ましくは、６０質量部以上、さらに好ましくは、７０質量部以上、とりわけ好ましくは、８０質量部以上である。また、水溶性ポリマーおよび非水溶性ポリマーの総量１００質量部に対して、水溶性ポリマーが、透気性および密着性の観点から、例えば、９９．９質量部以下、好ましくは、９９質量部以下、より好ましくは、９７質量部以下、さらに好ましくは、９５質量部以下である。 In such a secondary battery separator coating material raw material, the mass ratio of the water-soluble polymer to the water-insoluble polymer is appropriately set according to the purpose and application. For example, the total amount of the water-soluble polymer and the water-insoluble polymer is 100 parts by mass, and from the viewpoint of heat resistance, the water-soluble polymer is, for example, 40 parts by mass or more, preferably 50 parts by mass or more, more preferably 60 parts by mass. It is at least 70 parts by mass, more preferably at least 80 parts by mass. Further, from the viewpoint of air permeability and adhesion, the water-soluble polymer is, for example, 99.9 parts by mass or less, preferably 99 parts by mass or less, with respect to the total amount of 100 parts by mass of the water-soluble polymer and the water-insoluble polymer. More preferably, it is 97 parts by mass or less, and still more preferably 95 parts by mass or less.
　また、水溶性ポリマーおよび非水溶性ポリマーの総量１００質量部に対して、非水溶性ポリマーが、透気性および密着性の観点から、例えば、０．１質量部以上、好ましくは、１質量部以上、より好ましくは、３質量部以上、より好ましくは、５質量部以上である。
　また、水溶性ポリマーおよび非水溶性ポリマーの総量１００質量部に対して、非水溶性ポリマーが、耐熱性の観点から、例えば、６０質量部以下、好ましくは、５０質量部以下、より好ましくは、４０質量部以下、さらに好ましくは、３０質量部以下、とりわけ好ましくは、２０質量部以下である。 Further, from the viewpoint of air permeability and adhesion, the water-insoluble polymer is, for example, 0.1 part by mass or more, preferably 1 part by mass or more, relative to the total amount of 100 parts by mass of the water-soluble polymer and the water-insoluble polymer. , more preferably 3 parts by mass or more, more preferably 5 parts by mass or more.
Further, from the viewpoint of heat resistance, the water-insoluble polymer is, for example, 60 parts by mass or less, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, more preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less.
　なお、非水溶性ポリマーの質量および水溶性ポリマーの質量は、非水溶性ポリマー原料および水溶性ポリマー原料の仕込みの量から算出することができる。すなわち、上記の水溶性ポリマーの質量とは、水溶性ポリマー原料の質量を意味し、上記の非水溶性ポリマーの質量とは、非水溶性ポリマー原料の質量を意味する。 The mass of the water-insoluble polymer and the mass of the water-soluble polymer can be calculated from the amounts of the water-insoluble polymer raw material and the water-soluble polymer raw material. That is, the weight of the water-soluble polymer means the weight of the water-soluble polymer raw material, and the weight of the water-insoluble polymer means the weight of the water-insoluble polymer raw material.
　そして、本発明の二次電池セパレータ用コート材原料は、水溶性ポリマーと非水溶性ポリマーとの複合ポリマーを含み、水溶性ポリマーは、第１反応性官能基を含み、非水溶性ポリマーは、第１反応性官能基に化学結合可能な第２反応性官能基を含み、複合ポリマーにおいて、第１反応性官能基の少なくとも一部と、第２反応性官能基の少なくとも一部とが化学結合している。 Then, the raw material for the coating material for the secondary battery separator of the present invention contains a composite polymer of a water-soluble polymer and a water-insoluble polymer, the water-soluble polymer contains a first reactive functional group, and the water-insoluble polymer is comprising a second reactive functional group capable of chemically bonding to the first reactive functional group, wherein at least a portion of the first reactive functional group and at least a portion of the second reactive functional group are chemically bonded in the composite polymer; doing.
　そのため、上記の二次電池セパレータ用コート材原料は、貯蔵安定性、均一分散性および低粘性に優れる。さらに、上記の二次電池セパレータ用コート材原料によれば、耐熱性、透気性および密着性に優れる二次電池セパレータを得られる。 Therefore, the raw material for the secondary battery separator coating material is excellent in storage stability, uniform dispersibility and low viscosity. Furthermore, according to the raw material for the secondary battery separator coating material, it is possible to obtain a secondary battery separator that is excellent in heat resistance, air permeability, and adhesion.
　とりわけ、水溶性ポリマーと非水溶性ポリマーとが、複合ポリマーを形成せず、単に混合されている場合、水溶性ポリマーと非水溶性ポリマーとの比重差によって分離を生じる。また、分離を抑制するために、水溶性ポリマーと非水溶性ポリマーとを個別に用意し、使用時にこれらを混合することも検討されるが、作業が煩雑であり、さらに、混合物は均一分散性に劣る。 In particular, when the water-soluble polymer and the water-insoluble polymer are simply mixed without forming a composite polymer, separation occurs due to the difference in specific gravity between the water-soluble polymer and the water-insoluble polymer. Moreover, in order to suppress the separation, preparation of a water-soluble polymer and a water-insoluble polymer separately and mixing them at the time of use has been considered, but the work is complicated, and the mixture has uniform dispersibility. inferior to
　これに対して、上記の二次電池セパレータ用コート材原料では、水溶性ポリマーと非水溶性ポリマーとが化学結合し、複合ポリマーを形成しているため、比重差による分離を抑制でき、優れた貯蔵安定性を得られる。さらに、水溶性ポリマーと非水溶性ポリマーとが化学結合し、複合ポリマーを形成しているため、使用時における混合工程が不要であり、作業性および均一分散性に優れる。 On the other hand, in the raw material for the coating material for the secondary battery separator, the water-soluble polymer and the water-insoluble polymer are chemically bonded to form a composite polymer, so separation due to the difference in specific gravity can be suppressed, and it is excellent. Provides storage stability. Furthermore, since the water-soluble polymer and the water-insoluble polymer are chemically bonded to form a composite polymer, no mixing step is required during use, and workability and uniform dispersibility are excellent.
　さらに、水溶性ポリマーと非水溶性ポリマーとが化学結合しておらず、複合ポリマーを形成していない場合、水溶性ポリマー間の相互作用が大きいため、高粘度化を惹起する。 Furthermore, if the water-soluble polymer and the water-insoluble polymer are not chemically bonded and do not form a composite polymer, the interaction between the water-soluble polymers is large, causing an increase in viscosity.
　これに対して、上記の二次電池セパレータ用コート材原料では、水溶性ポリマーと非水溶性ポリマーとが化学結合し、複合ポリマーを形成しているため、水溶性ポリマーが非水溶性ポリマーに固定される。そのため、水溶性ポリマー間の相互作用が抑制され、その結果、高粘度化が抑制されて、優れた低粘性が得られる。 On the other hand, in the raw material for the secondary battery separator coating material, the water-soluble polymer and the water-insoluble polymer are chemically bonded to form a composite polymer, so the water-soluble polymer is fixed to the water-insoluble polymer. be done. Therefore, the interaction between the water-soluble polymers is suppressed, and as a result, an increase in viscosity is suppressed and excellent low viscosity is obtained.
　そして、本発明の二次電池セパレータ用コート材は、上記の二次電池セパレータ用コート材原料と、必要により、無機充填剤と、分散剤とを含んでいる。 The secondary battery separator coating material of the present invention contains the above-described secondary battery separator coating material raw material, and, if necessary, an inorganic filler and a dispersant.
　二次電池セパレータ用コート材原料の配合割合は、二次電池セパレータ用コート材原料と、無機充填剤と、分散剤との総量（以下、二次電池セパレータ用コート材成分とする。 The mixing ratio of the secondary battery separator coating material raw material is the total amount of the secondary battery separator coating material raw material, the inorganic filler, and the dispersant (hereinafter referred to as the secondary battery separator coating material component.
　）１００質量部（固形分）に対して、例えば、０．１質量部以上（固形分）であり、また、例えば、１０質量部以下（固形分）である。 ) for 100 parts by mass (solid content), for example, 0.1 parts by mass or more (solid content), and for example, 10 parts by mass or less (solid content).
　無機充填剤としては、例えば、酸化物、窒化物、炭化物、硫酸物、水酸化物、ケイ酸物および鉱物が挙げられる。酸化物としては、例えば、アルミナ、シリカ、チタニア、ジルコニア、マグネシア、セリア、イットリア、酸化亜鉛および酸化鉄が挙げられる。窒化物としては、例えば、窒化ケイ素、窒化チタンおよび窒化ホウ素が挙げられる。炭化物としては、例えば、シリコンカーバイドおよび炭酸カルシウムが挙げられる。硫酸物としては、例えば、硫酸マグネシウムおよび硫酸アルミニウムが挙げられる。水酸化物としては、例えば、水酸化アルミニウムおよび水酸化酸化アルミニウムが挙げられる。ケイ酸物としては、例えば、ケイ酸カルシウム、ケイ酸マグネシウム、ケイ藻土、ケイ砂およびガラスが挙げられる。鉱物としては、例えば、タルク、カオリナイト、ディカイト、ナクライト、ハロイサイト、パイロフィライト、モンモリロナイト、セリサイト、マイカ、アメサイト、ベントナイト、アスベストおよびゼオライトが挙げられる。無機充填剤として、好ましくは、酸化物および水酸化物が挙げられ、より好ましくは、酸化アルミニウムおよび水酸化酸化アルミニウムが挙げられる。 Inorganic fillers include, for example, oxides, nitrides, carbides, sulfates, hydroxides, silicates and minerals. Oxides include, for example, alumina, silica, titania, zirconia, magnesia, ceria, yttria, zinc oxide and iron oxide. Nitrides include, for example, silicon nitride, titanium nitride and boron nitride. Carbides include, for example, silicon carbide and calcium carbonate. Sulfates include, for example, magnesium sulfate and aluminum sulfate. Hydroxides include, for example, aluminum hydroxide and aluminum oxide hydroxide. Silicates include, for example, calcium silicate, magnesium silicate, diatomaceous earth, silica sand and glass. Minerals include, for example, talc, kaolinite, dekite, nacrite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite, asbestos and zeolites. Inorganic fillers preferably include oxides and hydroxides, more preferably aluminum oxides and aluminum oxide hydroxides.
　無機充填剤の配合割合は、二次電池セパレータ用コート材成分１００質量部（固形分）に対して、例えば、５０質量部以上（固形分）であり、また、例えば、９９．７質量部以下（固形分）である。 The mixing ratio of the inorganic filler is, for example, 50 parts by mass or more (solid content) with respect to 100 parts by mass (solid content) of the coating material component for the secondary battery separator, and, for example, 99.7 parts by mass or less. (solid content).
　分散剤としては、例えば、ポリカルボン酸アンモニウムおよびポリカルボン酸ナトリウムが挙げられる。分散剤がポリカルボン酸アンモニウムであれば、上記の二次電池セパレータ用コート材原料および無機充填剤を均一に分散させることができ、厚みが均一な塗布膜（後述）を得ることができる。 Dispersants include, for example, ammonium polycarboxylate and sodium polycarboxylate. When the dispersant is ammonium polycarboxylate, the raw material for the secondary battery separator coating material and the inorganic filler can be uniformly dispersed, and a coating film (described later) having a uniform thickness can be obtained.
　分散剤の配合割合は、二次電池セパレータ用コート材成分１００質量部（固形分）に対して、例えば、０．１質量部以上（固形分）であり、また、例えば、５質量部以下（固形分）である。 The mixing ratio of the dispersant is, for example, 0.1 parts by mass or more (solid content) with respect to 100 parts by mass (solid content) of the secondary battery separator coating material component, and for example, 5 parts by mass or less ( solid content).
　二次電池セパレータ用コート材を得るには、まず、水に、無機充填剤および分散剤を上記の割合で配合し、無機充填剤分散液を調製する。 In order to obtain a coating material for a secondary battery separator, first, an inorganic filler and a dispersant are blended with water in the above proportions to prepare an inorganic filler dispersion.
　次いで、その無機充填剤分散液に、二次電池セパレータ用コート材原料（または二次電池セパレータ用コート材原料を含む分散液）を上記の割合で配合し、撹拌する。これにより、二次電池セパレータ用コート材が得られる。 Next, the raw material for the coating material for the secondary battery separator (or the dispersion containing the raw material for the coating material for the secondary battery separator) is blended with the inorganic filler dispersion in the above ratio and stirred. Thereby, the coating material for secondary battery separators is obtained.
　撹拌方法は、特に限定されず、公知の攪拌装置が使用される。撹拌装置としては、例えば、ボールミル、ビーズミル、遊星ボールミル、振動ボールミル、サンドミル、コロイドミル、アトライター、ロールミル、高速インペラー分散、ディスパーザー、ホモジナイザー、高速衝撃ミル、超音波分散および撹拌羽根が挙げられる。 The stirring method is not particularly limited, and a known stirring device is used. Agitation devices include, for example, ball mills, bead mills, planetary ball mills, vibrating ball mills, sand mills, colloid mills, attritors, roll mills, high speed impeller dispersers, dispersers, homogenizers, high speed impact mills, ultrasonic dispersers and stirring blades.
　二次電池セパレータ用コート材は、例えば、水に分散された分散液として得られる。また、二次電池セパレータ用コート材には、必要により、公知の添加剤を含むことができる。添加剤としては、例えば、親水性樹脂、増粘剤、湿潤剤、消泡剤およびｐＨ調製剤が挙げられる。添加剤は、単独使用または２種類以上併用することができる。 The secondary battery separator coating material is obtained, for example, as a dispersion liquid dispersed in water. In addition, the coating material for the secondary battery separator can contain known additives, if necessary. Additives include, for example, hydrophilic resins, thickeners, wetting agents, antifoaming agents and pH adjusters. Additives can be used singly or in combination of two or more.
　上記の二次電池セパレータ用コート材は、上記の二次電池セパレータ用コート材原料を含むため、二次電池セパレータの生産性の向上を図ることができる。さらに、上記の二次電池セパレータ用コート材は、耐熱性、透気性および密着性に優れる二次電池セパレータを得られる。 Since the secondary battery separator coating material contains the above secondary battery separator coating material raw material, productivity of the secondary battery separator can be improved. Furthermore, the secondary battery separator coating material described above provides a secondary battery separator that is excellent in heat resistance, gas permeability and adhesion.
　そして、この二次電池セパレータ用コート材は、二次電池セパレータのコート材として、好適に用いることができる。 And this secondary battery separator coating material can be suitably used as a secondary battery separator coating material.
　本発明の二次電池セパレータは、公知の方法により製造することができる。 The secondary battery separator of the present invention can be produced by a known method.
　この方法では、まず、多孔膜を準備する。多孔膜としては、例えば、ポリオレフィン多孔膜および芳香族ポリアミド多孔膜が挙げられ、好ましくは、ポリオレフィン多孔膜が挙げられる。ポリオレフィンとしては、例えば、ポリエチレンおよびポリプロピレンが挙げられる。多孔膜は、必要に応じて、表面処理されていてもよい。表面処理としては、例えば、コロナ処理およびプラズマ処理が挙げられる。 In this method, first, a porous membrane is prepared. Porous membranes include, for example, polyolefin porous membranes and aromatic polyamide porous membranes, preferably polyolefin porous membranes. Polyolefins include, for example, polyethylene and polypropylene. The porous membrane may be surface-treated as necessary. Surface treatments include, for example, corona treatment and plasma treatment.
　多孔膜の厚みは、例えば、１μｍ以上、好ましくは、５μｍ以上である。また、多孔膜の厚みは、例えば、４０μｍ以下、好ましくは、２０μｍ以下である。 The thickness of the porous membrane is, for example, 1 μm or more, preferably 5 μm or more. Also, the thickness of the porous membrane is, for example, 40 μm or less, preferably 20 μm or less.
　次いで、この方法では、多孔膜の少なくとも片面に、上記のセパレータ用コート材を塗布する。その後、必要により、セパレータ用コート材を乾燥させ、これにより塗布膜を得る。 Next, in this method, the separator coating material is applied to at least one side of the porous membrane. Thereafter, if necessary, the separator coating material is dried to obtain a coating film.
　塗布方法としては、特に制限されないが、例えば、グラビアコーター法、小径グラビアコーター法、リバースロールコーター法、トランスファロールコーター法、キスコーター法、ディップコーター法、マイクログラビアコート法、ナイフコーター法、エアドクタコーター法、ブレードコーター法、ロッドコーター法、スクイズコーター法、キャストコーター法、ダイコーター法、スクリーン印刷法およびスプレー塗布法が挙げられる。 The coating method is not particularly limited, but examples include the gravure coater method, the small diameter gravure coater method, the reverse roll coater method, the transfer roll coater method, the kiss coater method, the dip coater method, the micro gravure coat method, the knife coater method, and the air doctor coater. method, blade coater method, rod coater method, squeeze coater method, cast coater method, die coater method, screen printing method and spray coating method.
　乾燥条件として、乾燥温度は、例えば、４０℃以上であり、また、例えば、８０℃以下である。乾燥後の塗布膜の厚みは、例えば、１μｍ以上、好ましくは、２μｍ以上である。また、乾燥後の塗布膜の厚みは、例えば、１０μｍ以下、好ましくは、８μｍ以下である。 As for the drying conditions, the drying temperature is, for example, 40°C or higher and, for example, 80°C or lower. The thickness of the coating film after drying is, for example, 1 μm or more, preferably 2 μm or more. Moreover, the thickness of the coating film after drying is, for example, 10 μm or less, preferably 8 μm or less.
　これにより、多孔膜と、多孔膜の少なくとも片面に配置される上記した二次電池セパレータ用コート材の塗布膜とを備えた二次電池セパレータが製造される。 As a result, a secondary battery separator comprising a porous membrane and a coated film of the above-described secondary battery separator coating material disposed on at least one side of the porous membrane is manufactured.
　なお、上記した説明では、多孔膜の少なくとも片面に、二次電池セパレータ用コート材の塗布膜を配置したが、多孔膜の両面に、上記の塗布膜を配置することもできる。 In the above description, the coating film of the secondary battery separator coating material is arranged on at least one side of the porous membrane, but the above coating film can also be arranged on both sides of the porous membrane.
　上記の二次電池セパレータは、上記の二次電池セパレータ用コート材の塗布膜を備えるため、生産性、耐熱性、透気性および密着性に優れる。 Since the above secondary battery separator is provided with the coating film of the above secondary battery separator coating material, it is excellent in productivity, heat resistance, air permeability and adhesion.
　また、上記の二次電池セパレータの製造方法によれば、耐熱性、透気性および密着性に優れる二次電池セパレータを、効率よく製造できる。 In addition, according to the method for manufacturing a secondary battery separator described above, a secondary battery separator having excellent heat resistance, air permeability, and adhesion can be efficiently manufactured.
　そして、この二次電池セパレータは、二次電池のセパレータとして、好適に用いることができる。 And this secondary battery separator can be suitably used as a separator for a secondary battery.
　本発明の二次電池は、正極と、負極と、正極および負極の間に配置される上記の二次電池セパレータと、正極、負極および上記の二次電池セパレータに含浸される電解質とを備える。 The secondary battery of the present invention includes a positive electrode, a negative electrode, the above-described secondary battery separator disposed between the positive electrode and the negative electrode, and an electrolyte impregnated in the positive electrode, the negative electrode, and the above-described secondary battery separator.
　正極としては、例えば、正極用集電体と、正極用集電体に積層される正極活物質とを備える公知の電極が用いられる。 As the positive electrode, for example, a known electrode comprising a positive electrode current collector and a positive electrode active material laminated on the positive electrode current collector is used.
　正極用集電体としては、公知の導電材料が挙げられる。導電材料としては、例えば、アルミニウム、チタン、ステンレス鋼、ニッケル、焼成炭素、導電性高分子および導電性ガラスが挙げられる。これらは、単独使用または２種類以上併用することができる。 A known conductive material can be used as the positive electrode current collector. Conductive materials include, for example, aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymers and conductive glasses. These can be used alone or in combination of two or more.
　正極活物質としては、特に制限されないが、例えば、リチウム含有遷移金属酸化物、リチウム含有リン酸塩およびリチウム含有硫酸塩が挙げられる。これらは、単独使用または２種類以上併用することができる。 The positive electrode active material is not particularly limited, but examples include lithium-containing transition metal oxides, lithium-containing phosphates, and lithium-containing sulfates. These can be used alone or in combination of two or more.
　負極としては、例えば、負極用集電体と、負極用集電体に積層される負極活物質とを備える公知の電極が用いられる。 As the negative electrode, for example, a known electrode comprising a negative electrode current collector and a negative electrode active material laminated on the negative electrode current collector is used.
　負極用集電体としては、例えば、銅およびニッケルが挙げられる。これらは、単独使用または２種類以上併用することができる。 Examples of current collectors for negative electrodes include copper and nickel. These can be used alone or in combination of two or more.
　負極活物質としては、例えば、グラファイト、ソフトカーボンおよびハードカーボンが挙げられる。これらは、単独使用または２種類以上併用することができる。 Examples of negative electrode active materials include graphite, soft carbon, and hard carbon. These can be used alone or in combination of two or more.
　二次電池が、リチウムイオン電池である場合、電解質としては、例えば、リチウム塩がカーボネート化合物に溶解された溶液が挙げられる。カーボネート化合物としては、例えば、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）およびエチルメチルカーボネート（ＥＭＣ）が挙げられる。 When the secondary battery is a lithium ion battery, the electrolyte may be, for example, a solution in which a lithium salt is dissolved in a carbonate compound. Carbonate compounds include, for example, ethylene carbonate (EC), propylene carbonate (PC) and ethyl methyl carbonate (EMC).
　そして、二次電池を製造するには、例えば、二次電池のセパレータを、正極と、負極との間に挟み込み、これらを電池筐体（セル）に収容して、電解質を電池筐体に注入する。 Then, in order to manufacture a secondary battery, for example, the separator of the secondary battery is sandwiched between the positive electrode and the negative electrode, these are housed in a battery housing (cell), and the electrolyte is injected into the battery housing. do.
　これにより、二次電池を得ることができる。 As a result, a secondary battery can be obtained.
　上記の二次電池は、上記の二次電池セパレータを備えているため、生産性、耐熱性、透気性および密着性に優れる。その結果、上記の二次電池は、生産性、耐熱性、透気性および密着性に優れる。 Since the above secondary battery includes the above secondary battery separator, it is excellent in productivity, heat resistance, air permeability, and adhesion. As a result, the above secondary battery is excellent in productivity, heat resistance, air permeability and adhesion.
　以下の記載において用いられる配合割合（含有割合）、物性値、パラメータなどの具体的数値は、上記の「発明を実施するための形態」において記載されている、それらに対応する配合割合（含有割合）、物性値、パラメータなど該当記載の上限値（「以下」、「未満」として定義されている数値）または下限値（「以上」、「超過」として定義されている数値）に代替することができる。また、以下の記載において特に言及がない限り、「部」および「％」は質量基準である。 Specific numerical values such as the mixing ratio (content ratio), physical property values, and parameters used in the following description are described in the above "Mode for Carrying Out the Invention", the corresponding mixing ratio (content ratio ), physical properties, parameters, etc. can. In the description below, "parts" and "%" are based on mass unless otherwise specified.
　１．二次電池セパレータ用コート材原料の調製
　実施例１～２３および比較例１～６
　攪拌機、還流冷却付きのセパラブルフラスコに、蒸留水６００部と、ラウリル硫酸ナトリウム（界面活性剤）１部とを仕込み、７０℃まで昇温させた。次いで、セパラブルフラスコに過硫酸カリウム（ＫＰＳ、重合開始剤）を表１～表４の記載に従って添加した。 1. Preparation of coating material raw materials for secondary battery separator Examples 1 to 23 and Comparative Examples 1 to 6
A separable flask equipped with a stirrer and reflux cooling was charged with 600 parts of distilled water and 1 part of sodium lauryl sulfate (surfactant), and the temperature was raised to 70°C. Then, potassium persulfate (KPS, polymerization initiator) was added to the separable flask according to the descriptions in Tables 1-4.
　表１～表４の記載に従って準備した水溶性ポリマー原料１００部を、３００部の蒸留水に溶解させた。次いで、その溶液を、窒素ガスで置換した上記のセパラブルフラスコに、７５℃で１８０分かけて連続的に添加した。その後、水溶性ポリマー原料を７５℃で４時間撹拌し、重合を完結させた。これにより、カルボキシ基（第１反応性官能基）を有する水溶性ポリマーの水溶液を得た。 　100 parts of the water-soluble polymer raw material prepared according to Tables 1 to 4 was dissolved in 300 parts of distilled water. Then, the solution was continuously added to the above-mentioned separable flask purged with nitrogen gas at 75° C. over 180 minutes. After that, the water-soluble polymer raw material was stirred at 75° C. for 4 hours to complete the polymerization. As a result, an aqueous solution of a water-soluble polymer having a carboxy group (first reactive functional group) was obtained.
　次いで、表１～表４の記載に従って準備した非水溶性ポリマー原料を、石鹸水で乳化させた。次いで、その乳化液を、上記の水溶性ポリマーの水溶液に一括添加した。これらの混合物を、攪拌しながら７５℃で４時間撹拌し、重合を完結させた。これにより、グリシジル基（第２反応性官能基）を有する非水溶性ポリマーを得た。また、これとともに、水溶性ポリマーのカルボキシ基と非水溶性ポリマーのグリシジル基とを反応させ、水溶性ポリマーおよび非水溶性ポリマーが化学結合した複合ポリマーを得た。なお、比較例１～６の非水溶性ポリマーは、グリシジル基（第２反応性官能基）を有しておらず、水溶性ポリマーと非水溶性ポリマーとが反応しなかった。そのため、比較例１～６では、複合ポリマーを得られず、水溶性ポリマーと非水溶性ポリマーとの混合ポリマーを得た。 Then, the water-insoluble polymer raw materials prepared according to the descriptions in Tables 1 to 4 were emulsified with soapy water. Then, the emulsion was added all at once to the aqueous solution of the water-soluble polymer. These mixtures were stirred at 75° C. for 4 hours with stirring to complete the polymerization. As a result, a water-insoluble polymer having a glycidyl group (second reactive functional group) was obtained. At the same time, the carboxy group of the water-soluble polymer and the glycidyl group of the water-insoluble polymer were reacted to obtain a composite polymer in which the water-soluble polymer and the water-insoluble polymer were chemically bonded. The water-insoluble polymers of Comparative Examples 1 to 6 did not have a glycidyl group (second reactive functional group), and the water-insoluble polymer did not react with the water-insoluble polymer. Therefore, in Comparative Examples 1 to 6, a composite polymer was not obtained, and a mixed polymer of a water-soluble polymer and a water-insoluble polymer was obtained.
　これにより、複合ポリマーの分散液または混合ポリマーの分散液（以下、ポリマー分散液）として、セパレータ用コート材原料を得た。分散液の固形分濃度は、１０．０質量％であった。 As a result, a separator coating material raw material was obtained as a composite polymer dispersion or a mixed polymer dispersion (hereinafter referred to as polymer dispersion). The solid content concentration of the dispersion was 10.0% by mass.
　また、非水溶性ポリマーおよび水溶性ポリマーのガラス転移温度（Ｔｇ、単位：℃）を、下記のＦＯＸ式により算出した。 Also, the glass transition temperature (Tg, unit: °C) of the water-insoluble polymer and the water-soluble polymer was calculated by the following FOX formula.
　１／Ｔｇ＝Ｗ１／Ｔｇ１＋Ｗ２／Ｔｇ２＋・・・＋Ｗｎ／Ｔｇｎ（１）
［式中、Ｔｇは共重合体のガラス転移温度（単位：Ｋ）、Ｔｇｉ（ｉ＝１、２、・・・ｎ）は、単量体ｉが単独重合体を形成するときのガラス転移温度（単位：Ｋ）、Ｗｉ（ｉ＝１、２、・・・ｎ）は、単量体ｉの全単量体中の質量分率を表す。］ 1 /Tg = W1/Tg1 + W2/Tg2+...+ Wn / Tgn ( 1 )
[In the formula, Tg is the glass transition temperature of the copolymer (unit: K), Tg i (i = 1, 2, ... n) is the glass transition temperature when the monomer i forms a homopolymer. Temperature (unit: K) and W i (i=1, 2, . . . n) represent the mass fraction of monomer i in all monomers. ]
　また、非水溶性ポリマーおよび水溶性ポリマーの溶解性パラメータ（ＳＰ値、単位；（ｃａｌ／ｃｍ３）１／２）を、Ｍｉｌｌｉｏｎ　Ｚｉｌｌｉｏｎ　Ｓｏｆｔｗａｒｅ社の計算ソフトＣＨＥＯＰＳ（ｖｅｒｓｉｏｎ４．０）にて算出した。計算手法は、Ｃｏｍｐｕｔａｔｉｏｎａｌ　Ｍａｔｅｒｉａｌｓ　Ｓｃｉｅｎｃｅ　ｏｆ　Ｐｏｌｙｍｅｒｓ（Ａ．Ａ．Ａｓｋａｄｓｋｉｉ、　Ｃａｍｂｒｉｄｇｅ　Ｉｎｔｌ　Ｓｃｉｅｎｃｅ　Ｐｕｂ　（２００５／１２／３０））Ｃｈａｐｔｅｒ　ＸＩＩに記載されている方法を採用した。 Further, the solubility parameters (SP value, unit: (cal/cm 3 ) 1/2 ) of the water-insoluble polymer and the water-soluble polymer were calculated using calculation software CHEOPS (version 4.0) of Million Zillion Software. As a calculation method, the method described in Computational Materials Science of Polymers (AA Askadskii, Cambridge Intl Science Pub (2005/12/30)) Chapter XII was adopted.
　また、水溶性ポリマーの重量平均分子量を、以下の方法および条件で測定した。すなわち、水溶性ポリマーの重合が完結した時点で、水溶性ポリマーをサンプリングした。次いで、ＧＰＣ装置（装置名：Ｐ　ＫＰ－２２、フロム社）を用いて、サンプルの重量平均分子量（Ｍｗ）を求めた。なお、測定条件を下記する。また、重量平均分子量は、標準ポリエチレングリコール／ポリエチレンオキサイド換算分子量である。 In addition, the weight average molecular weight of the water-soluble polymer was measured by the following method and conditions. That is, when the polymerization of the water-soluble polymer was completed, the water-soluble polymer was sampled. Next, the weight average molecular weight (Mw) of the sample was determined using a GPC device (device name: PKP-22, Fromm). In addition, the measurement conditions are described below. Also, the weight average molecular weight is a standard polyethylene glycol/polyethylene oxide equivalent molecular weight.
　・サンプル濃度：０．１（ｗ／ｖ）％
　・サンプル注入量：１００μＬ
　・溶離液：０．２Ｍ　ＮａＮＯ３／アクリロニトリル（ＡＮ）＝９０／１０
　・流速：１．０ｍｌ／ｍｉｎ
　・測定温度：４０℃
　・カラム：ＳｈｏｄｅｘｏｈＰＡＫ　ＳＢ－８０６Ｍ　ＨＱ　×２ ・Sample concentration: 0.1 (w/v)%
・Sample injection volume: 100 μL
- Eluent: 0.2M NaNO3 /acrylonitrile (AN) = 90/10
・Flow rate: 1.0 ml/min
・Measurement temperature: 40°C
・ Column: ShodexohPAK SB-806M HQ × 2
　比較例７
　国際公開ＷＯ２０１７／０２６０９５号の実施例１に準拠して、セパレータ用コート材原料としての分散液を得た。 Comparative example 7
A dispersion liquid as a separator coating material raw material was obtained according to Example 1 of International Publication WO2017/026095.
　すなわち、攪拌機、温度計、還流冷却管および窒素ガス導入管を備えた四つ口フラスコに、表１～表４の記載に従って、水溶性ポリマー原料を仕込み、窒素ガスで反応系内の酸素を除去した。次いで、撹拌下、重合開始剤として５％過硫酸アンモニウム水溶液７部および５％亜硫酸水素ナトリウム水溶液３部をフラスコに投入した後、室温から８０℃まで昇温し、３時間保温して、水溶性ポリマー原料を重合させた。その後、イオン交換水１６２部を加え、水溶性ポリマーの水溶液を得た。 That is, a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube is charged with water-soluble polymer raw materials according to Tables 1 to 4, and nitrogen gas is used to remove oxygen in the reaction system. did. Then, with stirring, 7 parts of a 5% aqueous ammonium persulfate solution and 3 parts of a 5% aqueous sodium hydrogen sulfite solution as polymerization initiators were added to the flask, then the temperature was raised from room temperature to 80 ° C. and kept for 3 hours to obtain a water-soluble polymer. The raw material was polymerized. After that, 162 parts of ion-exchanged water was added to obtain an aqueous solution of a water-soluble polymer.
　別途、撹拌機を備えた反応器に、イオン交換水７０部、乳化剤としてのラウリル硫酸ナトリウム０．１５部、および、重合開始剤としてのペルオキソ二硫酸アンモニウム０．５部を供給し、気相部を窒素ガスで置換して、６０℃に昇温した。その後、表１～表４の記載に従って、反応器に、非水溶性ポリマー原料を連続的に添加し、添加中は６０℃で重合させ、添加終了後は７０℃で３時間撹拌してから反応を終了させた。これにより、非水溶性ポリマーの分散液を得た。 Separately, 70 parts of ion-exchanged water, 0.15 parts of sodium lauryl sulfate as an emulsifier, and 0.5 parts of ammonium peroxodisulfate as a polymerization initiator are supplied to a reactor equipped with a stirrer, and the gas phase portion is After purging with nitrogen gas, the temperature was raised to 60°C. Thereafter, according to the descriptions in Tables 1 to 4, the water-insoluble polymer raw material was continuously added to the reactor, polymerized at 60°C during the addition, and stirred at 70°C for 3 hours after the addition, and then reacted. terminated. This gave a water-insoluble polymer dispersion.
　そして、得られた水溶性ポリマーの分散液と、非水溶性ポリマーの分散液とを混合し、セパレータ用コート材原料として、混合ポリマーの分散液（ポリマー分散液）を得た。なお、混合比率は、水溶性ポリマー１質量部に対して、粒子状ポリマーが２質量部となる割合とした。 Then, the obtained water-soluble polymer dispersion and the water-insoluble polymer dispersion were mixed to obtain a mixed polymer dispersion (polymer dispersion) as a separator coating material raw material. The mixing ratio was such that the particulate polymer was 2 parts by mass with respect to 1 part by mass of the water-soluble polymer.
　比較例８
　攪拌機、還流冷却付きのセパラブルフラスコに、蒸留水６００部と、ラウリル硫酸ナトリウム（界面活性剤）１部とを仕込み、７０℃まで昇温させた。次いで、セパラブルフラスコに過硫酸カリウム（ＫＰＳ、重合開始剤）を表５の記載に従って添加した。 Comparative example 8
A separable flask equipped with a stirrer and reflux cooling was charged with 600 parts of distilled water and 1 part of sodium lauryl sulfate (surfactant), and the temperature was raised to 70°C. Then, potassium persulfate (KPS, polymerization initiator) was added to the separable flask according to Table 5.
　表５の記載に従って準備した高ＳＰ値ポリマー原料１００部を、３００部の蒸留水に入荷させた。なお、乳化剤として、ラウリル硫酸ナトリウム（界面活性剤）２部を添加した。次いで、その乳化液を、窒素ガスで置換した上記のセパラブルフラスコに、７５℃で１８０分かけて連続的に添加した。その後、乳化液を、７５℃で２時間撹拌し、重合を完結させた。これにより、カルボキシ基（第１反応性官能基）を有する高ＳＰ値ポリマーの水分散液を得た。 100 parts of a high SP value polymer raw material prepared according to Table 5 was added to 300 parts of distilled water. As an emulsifier, 2 parts of sodium lauryl sulfate (surfactant) was added. Then, the emulsified liquid was continuously added to the separable flask replaced with nitrogen gas at 75° C. over 180 minutes. The emulsion was then stirred at 75° C. for 2 hours to complete the polymerization. As a result, an aqueous dispersion of a high SP value polymer having a carboxy group (first reactive functional group) was obtained.
　次いで、表５の記載に従って準備した低ＳＰ値ポリマー原料を、ラウリル硫酸ナトリウム（界面活性剤）１部で乳化させた。次いで、その乳化液を、上記の高ＳＰ値ポリマーの水分散液に一括添加した。これらの混合物を、攪拌しながら７５℃で４時間撹拌し、重合を完結させた。これにより、グリシジル基（第２反応性官能基）を有する低ＳＰ値ポリマーを得た。また、これとともに、高ＳＰ値ポリマーと低ＳＰ値ポリマーとがグリシジル基とカルボキシ基で結合したコアシェル水分散液を得た。 Then, the low SP value polymer raw material prepared according to Table 5 was emulsified with 1 part of sodium lauryl sulfate (surfactant). Then, the emulsion was added all at once to the aqueous dispersion of the high SP value polymer. These mixtures were stirred at 75° C. for 4 hours with stirring to complete the polymerization. As a result, a low SP value polymer having a glycidyl group (second reactive functional group) was obtained. Together with this, a core-shell aqueous dispersion was obtained in which a high SP value polymer and a low SP value polymer were bonded via a glycidyl group and a carboxy group.
　比較例９
　国際公開ＷＯ２０１０／１３４５０１号の実施例１に準拠して、セパレータ用コート材原料としての分散液を得た。 Comparative example 9
A dispersion liquid was obtained as a coating material raw material for a separator according to Example 1 of International Publication WO2010/134501.
　すなわち、撹拌機付きのオートクレーブに、トルエン２３０部と、アクリル酸ｎ－ブチル５０部と、スチレンオリゴマー５０部と、ｔ－ブチルパーオキシー２－エチルヘキサネート（重合開始剤）１部とを入れ、十分に撹拌した。なお、スチレンオリゴマーは、片末端メタクリロイル化ポリスチレンオリゴマー（東亜合成化学工業社製、商品名ＡＳ－６、ＳＰ値９．９（ｃａｌ／ｃｍ３）１／２）であった。 That is, 230 parts of toluene, 50 parts of n-butyl acrylate, 50 parts of styrene oligomer, and 1 part of t-butylperoxy-2-ethylhexanate (polymerization initiator) are placed in an autoclave equipped with a stirrer, Stir well. The styrene oligomer was a one-end methacryloyl polystyrene oligomer (manufactured by Toagosei Chemical Industry Co., Ltd., trade name AS-6, SP value 9.9 (cal/cm 3 ) 1/2 ).
　その後、オートクレーブを、９０℃に加温して、上記の各成分を重合させた。これにより、重合体（以下、グラフトポリマーと称する。）の溶液を得た。グラフトポリマーの主鎖は、アクリル酸ｎ－ブチル（電解液に対する膨潤性を示す成分）により構成されていた。また、グラフトポリマーの側鎖は、スチレン（電解液に対する膨潤性を示さない成分）により構成されていた。 After that, the autoclave was heated to 90°C to polymerize the above components. As a result, a polymer (hereinafter referred to as graft polymer) solution was obtained. The main chain of the graft polymer was composed of n-butyl acrylate (a component exhibiting swelling properties with respect to electrolyte). Also, the side chains of the graft polymer were composed of styrene (a component that does not swell with the electrolyte).
　溶液の固形分濃度から重合転化率を算出した。重合添加率は、約９８％であった。グラフトポリマーの重量平均分子量は約５万であった。グラフトポリマーのガラス転移温度は２５℃であった。 The polymerization conversion rate was calculated from the solid content concentration of the solution. The polymerization addition rate was about 98%. The weight average molecular weight of the graft polymer was about 50,000. The glass transition temperature of the graft polymer was 25°C.
　２．二次電池セパレータ用コート材および二次電池セパレータの製造
　各実施例および各比較例の二次電池セパレータ用コート材原料を使用して、二次電池セパレータ用コート材を調製し、二次電池セパレータを得た。 2. Coating Material for Secondary Battery Separator and Production of Secondary Battery Separator Using the coating material raw material for secondary battery separator of each example and each comparative example, a coating material for secondary battery separator is prepared, and a secondary battery separator is prepared. got
　すなわち、顔料として、水酸化酸化アルミニウム（大明化学社製、ベーマイトＧｒａｄｅＣ０６、粒子径：０．７μｍ）１００質量部、分散剤として、ポリカルボン酸アンモニウム水溶液（サンノプコ社製、ＳＮディスパーサント５４６８）３．０質量部（固形分換算）を、１１０質量部の水に均一に分散させて顔料分散液を得た。次いで、この顔料分散液に、ポリマー分散液（二次電池セパレータ用コート材原料）を、固形分換算で５質量部となるよう添加し、更に固形分が４０質量％となるよう水を加えて調整し、１５分間撹拌して二次電池セパレータ用コート材を調製した。 That is, 100 parts by mass of aluminum hydroxide oxide (Boehmite Grade C06, particle size: 0.7 μm, manufactured by Taimei Chemical Co., Ltd.) as a pigment, and an aqueous ammonium polycarboxylate solution (SN Dispersant 5468, manufactured by San Nopco Co., Ltd.) as a dispersant3. 0 parts by mass (in terms of solid content) was uniformly dispersed in 110 parts by mass of water to obtain a pigment dispersion. Next, a polymer dispersion (raw material for secondary battery separator coating material) was added to the pigment dispersion so that the solid content was 5 parts by mass, and water was added so that the solid content was 40% by mass. The mixture was adjusted and stirred for 15 minutes to prepare a secondary battery separator coating material.
　一方、ポリオレフィン樹脂多孔膜の表面を、コロナ処理した。より具体的には、ポリオレフィン樹脂多孔膜として、品番ＳＷ５０９Ｃ＋（膜厚９．６μｍ、空隙率４０．６％、透気度１５８ｇ／１００ｍｌ、面密度５．５ｇ／ｍ２、常州星源新能源材料有限公司）を準備した。次いで、ポリオレフィン樹脂多孔膜の表面を、Ａ４サイズにカットし、その後、ポリオレフィン樹脂多孔膜の表面を、スイッチバック自動走行式コロナ表面処理装置（ウェッジ株式会社製）により、出力０．１５ＫＷ、搬送スピード３．０ｍ／ｓ×２回、および、コロナ放電距離９ｍｍの条件で、コロナ処理した。 On the other hand, the surface of the polyolefin resin porous membrane was corona-treated. More specifically, as a polyolefin resin porous film, product number SW509C+ (film thickness 9.6 μm, porosity 40.6%, air permeability 158 g/100 ml, surface density 5.5 g/m 2 , Changzhou Xingyuan New Energy Materials Co., Ltd.) was prepared. Next, the surface of the polyolefin resin porous membrane is cut to A4 size, and then the surface of the polyolefin resin porous membrane is treated with a switchback automatic traveling type corona surface treatment device (manufactured by Wedge Co., Ltd.) at an output of 0.15 KW and a conveying speed. Corona treatment was performed under the conditions of 3.0 m/s×2 times and a corona discharge distance of 9 mm.
　次いで、ワイヤーバーを用いて、コロナ処理したポリオレフィン樹脂多孔膜の表面に、上記の二次電池セパレータ用コート材を塗工した。塗工後、５０℃で乾燥することにより、ポリオレフィン樹脂多孔膜の表面に５μｍの塗布膜を形成した。 Then, using a wire bar, the surface of the corona-treated polyolefin resin porous membrane was coated with the above coating material for a secondary battery separator. After coating, the coating was dried at 50° C. to form a coating film of 5 μm on the surface of the polyolefin resin porous membrane.
　これにより、二次電池セパレータを製造した。 As a result, a secondary battery separator was manufactured.
　３．評価
（１）耐熱性
　二次電池セパレータを５ｃｍ×５ｃｍに切り出し、これを試験片とした。この試験片を１５０℃×１時間オーブン内に放置した後、各辺の長さを測定し、熱収縮率を算出した。
　また、耐熱性に関して次の基準で優劣を評価した。 3. Evaluation (1) Heat resistance A secondary battery separator was cut into a size of 5 cm x 5 cm, and this was used as a test piece. After leaving this test piece in an oven at 150° C. for 1 hour, the length of each side was measured and the thermal shrinkage rate was calculated.
In addition, the heat resistance was evaluated according to the following criteria.
　◎　：熱収縮率が１５％未満であった。
　○　：熱収縮率が１５％以上２５％未満であった。
　△　：熱収縮率が２５％以上６５％未満であった。
　△△：熱収縮率が６５％以上８０％未満であった。
　×　：熱収縮率が８０％以上であった。 A: The heat shrinkage rate was less than 15%.
○: The heat shrinkage rate was 15% or more and less than 25%.
Δ: The heat shrinkage rate was 25% or more and less than 65%.
△△: The heat shrinkage rate was 65% or more and less than 80%.
x: The heat shrinkage rate was 80% or more.
（２）透気性
　二次電池セパレータについて、旭精工社製の王研式透気度平滑度試験機により、ＪＩＳ－Ｐ－８１１７に準じて測定した透気抵抗度を求めた。透気抵抗度が小さいほど、イオン透過性に優れると評価した。また、イオン透過性に関して次の基準で優劣を評価した。 (2) Air Permeability With respect to the secondary battery separator, the air resistance was measured according to JIS-P-8117 using an Oken type air permeability smoothness tester manufactured by Asahi Seiko Co., Ltd. It was evaluated that the smaller the air resistance, the better the ion permeability. In addition, the ion permeability was evaluated according to the following criteria.
　◎：透気抵抗度が１８０ｓ／１００ｍＬ未満であった。
　○：透気抵抗度が１８０ｓ／１００ｍＬ以上２２０ｓ／１００ｍＬ未満であった。
　△：透気抵抗度が２２０ｓ／１００ｍＬ以上３００ｓ／１００ｍＬ未満であった。
　×：透気抵抗度が３００ｓ／１００ｍＬ以上であった。 A: Air resistance was less than 180 s/100 mL.
○: The air resistance was 180 s/100 mL or more and less than 220 s/100 mL.
Δ: Air permeation resistance was 220 s/100 mL or more and less than 300 s/100 mL.
x: Air resistance was 300 s/100 mL or more.
（３）密着性
　二次電池セパレータを５ｃｍ×１０ｃｍに切り出し、これを試験片とした。ＪＩＳ　Ｚ１５２２に準ずる方法で二次電池セパレータ用コート材の塗布膜に、セロハン粘着テープを貼り付け、１８０°ピール試験を実施した。その際、セロハン粘着テープの引っ張り速度は１０ｍｍ／分とした。測定は３回実施し、その平均値を算出した。また、密着性に関して次の基準で優劣を評価した。 (3) Adhesion A secondary battery separator was cut into a size of 5 cm×10 cm, and this was used as a test piece. A cellophane adhesive tape was attached to the coating film of the secondary battery separator coating material by a method according to JIS Z1522, and a 180° peel test was performed. At that time, the cellophane adhesive tape was pulled at a speed of 10 mm/min. The measurement was performed 3 times and the average value was calculated. In addition, the adhesion was evaluated according to the following criteria.
　◎　：接着強度の平均値が７０Ｎ／ｍ以上であった。
　○　：接着強度の平均値が５０Ｎ／ｍ以上７０Ｎ／ｍ未満であった。
　△　：接着強度の平均値が２０Ｎ／ｍ以上５０Ｎ／ｍ未満であった。
　△△：接着強度の平均値が１／ｍ以上２０Ｎ／ｍ未満であった。
　×　：接着強度の平均値が１Ｎ／ｍ未満であった。 A: The average adhesive strength was 70 N/m or more.
Good: The average adhesive strength was 50 N/m or more and less than 70 N/m.
Δ: The average adhesive strength was 20 N/m or more and less than 50 N/m.
ΔΔ: The average adhesive strength was 1/m or more and less than 20 N/m.
x: The average adhesive strength was less than 1 N/m.
（４）貯蔵安定性
　二次電池セパレータ用コート材原料の貯蔵安定性を、以下の方法で評価した。すなわち、ポリマー分散液（二次電池セパレータ用コート材原料）１Ｌを、４０℃の恒温槽に保管した。半年後に、複合ポリマーの分散液の粘度変化およびｐＨ変化を測定した。さらに、複合ポリマーの分散液の外観変化（層分離および色相）を、目視で観察した。そして、粘度変化、ｐＨ変化および外観変化をそれぞれ１～４点で評価し、最も低い点数によって、貯蔵安定性を評価した。評価基準を下記する。 (4) Storage stability Storage stability of the coating material raw material for secondary battery separators was evaluated by the following method. That is, 1 L of polymer dispersion (coating material raw material for secondary battery separator) was stored in a constant temperature bath at 40°C. After half a year, the viscosity change and pH change of the composite polymer dispersion were measured. Furthermore, changes in appearance (layer separation and hue) of the composite polymer dispersion were visually observed. Viscosity change, pH change and appearance change were each evaluated on a scale of 1 to 4, and the lowest score was used to evaluate storage stability. Evaluation criteria are described below.
　・粘度変化
　４点：０％以上５％以下
　３点：５％超過１０％以下
　２点：１０％超過３０％以下
　１点：３０％超過 ・ Viscosity change 4 points: 0% or more and 5% or less 3 points: 5% or more and 10% or less 2 points: 10% or more and 30% or less 1 point: 30% or less
　・ｐＨ変化
　４点：０以上０．５以下
　３点：０．５超過１．０以下
　２点：１．０超過２．０以下
　１点：２．０超過 ・pH change 4 points: 0 to 0.5 3 points: over 0.5 to 1.0 or less 2 points: over 1.0 to 2.0 or less 1 point: over 2.0
　・外観変化
　４点：外観変化なし。
　３点：僅かな外観変化あり。
　２点：外観変化あり。
　１点：顕著な外観変化あり。 - Appearance change 4 points: No change in appearance.
3 points: Slight change in appearance.
2 points: Appearance changed.
1 point: Remarkable change in appearance.
　・総合評価（貯蔵安定性）
　◎：粘度変化、ｐＨ変化および外観変化の評価における最低点が、４点。
　○：粘度変化、ｐＨ変化および外観変化の評価における最低点が、３点。
　△：粘度変化、ｐＨ変化および外観変化の評価における最低点が、２点。
　×：粘度変化、ｐＨ変化および外観変化の評価における最低点が、１点。 ・Comprehensive evaluation (storage stability)
A: The lowest score in the evaluation of viscosity change, pH change, and appearance change is 4 points.
○: The lowest score in the evaluation of viscosity change, pH change, and appearance change is 3 points.
Δ: The lowest score in the evaluation of viscosity change, pH change, and appearance change is 2 points.
x: The lowest score in the evaluation of viscosity change, pH change, and appearance change is 1 point.
（５）均一分散性
　二次電池セパレータ用コート材原料の均一分散性を、以下の方法で評価した。すなわち、上記二次電池セパレータ用コート材のゼータ電位を、ゼータ電位測定装置（大塚電子株式会社製ＥＬＳＺ－２０００）濃厚系セルにて、１０回測定した。そして、下記の基準により、均一分散性を評価した。 (5) Uniform dispersibility Uniform dispersibility of the coating material raw material for the secondary battery separator was evaluated by the following method. That is, the zeta potential of the secondary battery separator coating material was measured 10 times with a zeta potential measuring device (ELSZ-2000 manufactured by Otsuka Electronics Co., Ltd.) in a concentrated cell. Then, uniform dispersibility was evaluated according to the following criteria.
　◎：ゼータ電位の測定１０回中の最大値と最小値の差が、測定１０回の平均値に対して５％未満。
　○：ゼータ電位の測定１０回中の最大値と最小値の差が、測定１０回の平均値に対して５％以上１０％未満。
　△：ゼータ電位の測定１０回中の最大値と最小値の差が、測定１０回の平均値に対して１０％以上１５％未満。
　×：ゼータ電位の測定１０回中の最大値と最小値の差が、測定１０回の平均値に対して１５％以上。 A: The difference between the maximum value and the minimum value in 10 measurements of zeta potential is less than 5% with respect to the average value of 10 measurements.
○: The difference between the maximum value and the minimum value in 10 measurements of zeta potential is 5% or more and less than 10% with respect to the average value of 10 measurements.
Δ: The difference between the maximum value and the minimum value in 10 measurements of zeta potential is 10% or more and less than 15% with respect to the average value of 10 measurements.
x: The difference between the maximum value and the minimum value in 10 measurements of zeta potential is 15% or more with respect to the average value of 10 measurements.
（６）低粘性
　二次電池セパレータ用コート材原料の低粘性を、以下の方法で評価した。すなわち、ポリマー分散液の固形分濃度を１０質量％に調整し、その分散液の２５℃における粘度をＢＭ型粘度計にて測定した。評価基準を下記する。 (6) Low Viscosity Low viscosity of the coating material raw material for secondary battery separators was evaluated by the following method. That is, the solid content concentration of the polymer dispersion was adjusted to 10% by mass, and the viscosity of the dispersion at 25° C. was measured with a BM viscometer. Evaluation criteria are described below.
　◎：１０００ｍＰａ・ｓ未満
　○：１０００ｍＰａ・ｓ以上２０００ｍＰａ・ｓ未満
　△：２０００ｍＰａ・ｓ以上６０００ｍＰａ・ｓ未満
　×：６０００ｍＰａ・ｓ以上 ◎: Less than 1000 mPa s ○: 1000 mPa s or more and less than 2000 mPa s △: 2000 mPa s or more and less than 6000 mPa s ×: 6000 mPa s or more
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　なお、表中の水溶性ポリマー原料の配合処方（質量部）は、水溶性ポリマー１００質量部に対する原料成分（モノマー）の配合量を示す。また、非水溶性ポリマー原料の配合処方（質量部）は、非水溶性ポリマー１００質量部に対する原料成分（モノマー）の配合量を示す。また、水溶性ポリマーと非水溶性ポリマーとの比率は、表中の「非水溶性ポリマー／水溶性ポリマー（質量比）」に従う。 The blending recipe (parts by mass) of the water-soluble polymer raw material in the table indicates the blending amount of the raw material component (monomer) with respect to 100 parts by mass of the water-soluble polymer. Further, the blending recipe (parts by mass) of the water-insoluble polymer raw material indicates the blending amount of the raw material component (monomer) with respect to 100 parts by mass of the water-insoluble polymer. Moreover, the ratio of the water-soluble polymer and the water-insoluble polymer follows "water-insoluble polymer/water-soluble polymer (mass ratio)" in the table.
　また、表中の高ＳＰ値ポリマー原料の配合処方（質量部）は、高ＳＰ値ポリマー１００質量部に対する原料成分（モノマー）の配合量を示す。また、低ＳＰ値ポリマー原料の配合処方（質量部）は、低ＳＰ値ポリマー１００質量部に対する原料成分（モノマー）の配合量を示す。また、高ＳＰ値ポリマーと低ＳＰ値ポリマーとの比率は、表中の「高ＳＰ値ポリマー／低ＳＰ値ポリマー（質量比）」に従う。 In addition, the blending recipe (parts by mass) of the high SP value polymer raw material in the table indicates the blending amount of the raw material component (monomer) per 100 parts by mass of the high SP value polymer. The blending recipe (parts by mass) of the low SP value polymer raw material indicates the blending amount of the raw material component (monomer) with respect to 100 parts by mass of the low SP value polymer. Further, the ratio of the high SP value polymer and the low SP value polymer follows "high SP value polymer/low SP value polymer (mass ratio)" in the table.
　また、表中の略号の詳細を下記する。
　Ｍａｍ：メタクリルアミド
　ＡＭ：アクリルアミド
　Ｍａｃ：メタクリル酸
　Ａｃ：アクリル酸
　ＨＥＭＡ：２－ヒドロキシエチルメタクリレート
　ＤＭＡＥＭＡ：Ｎ，Ｎ－ジメチルアミノエチルメタクリレート
　ＤＭＡＭ：ジメチルアクリルアミド
　Ｓｔ：スチレン
　ＭＭＡ：メチルメタクリレート
　ＢＡ：ｎ－ブチルアクリレート
　２ＥＨＡ：２エチルヘキシルアクリレート
　ＧＭＡ：グリシジルメタクリレート
　ＡＮ：アクリロニトリル
　Ｎ－ＭＡＭ：Ｎ－メチロールアクリルアミド
　ＡＧＥ：アリルグリシジルエーテル
　ＫＰＳ：過硫酸カリウム
　Ｔｇ：ガラス転移温度、単位：℃
　ＳＰ値：溶解度パラメータ、単位：（ｃａｌ／ｃｍ３）１／２ Further, the details of the abbreviations in the table are described below.
Mam: methacrylamide AM: acrylamide Mac: methacrylic acid Ac: acrylic acid HEMA: 2-hydroxyethyl methacrylate DMAEMA: N,N-dimethylaminoethyl methacrylate DMAM: dimethylacrylamide St: styrene MMA: methyl methacrylate BA: n-butyl acrylate 2EHA : 2 ethylhexyl acrylate GMA: glycidyl methacrylate AN: acrylonitrile N-MAM: N-methylolacrylamide AGE: allyl glycidyl ether KPS: potassium persulfate Tg: glass transition temperature, unit: °C
SP value: solubility parameter, unit: (cal/cm 3 ) 1/2
　なお、上記発明は、本発明の例示の実施形態として提供したが、これは単なる例示にすぎず、限定的に解釈してはならない。当該技術分野の当業者によって明らかな本発明の変形例は、後記特許請求の範囲に含まれるものである。 Although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an illustration and should not be construed as limiting. Variations of the invention that are obvious to those skilled in the art are intended to be included in the following claims.
　本発明の二次電池セパレータ用コート材原料、二次電池セパレータ用コート材、二次電池セパレータ、二次電池セパレータの製造方法、および、二次電池は、二次電池分野において、好適に用いられる。
  The secondary battery separator coating material raw material, the secondary battery separator coating material, the secondary battery separator, the method for producing the secondary battery separator, and the secondary battery of the present invention are suitably used in the secondary battery field. .
 

Claims (12)

  1. 　ＳＰ値１３．０（ｃａｌ／ｃｍ３）１／２以上の水溶性ポリマーと、
    　ＳＰ値１３．０（ｃａｌ／ｃｍ３）１／２未満の非水溶性ポリマーとの複合ポリマーを含み、
    　前記水溶性ポリマーは、第１反応性官能基を含み、
    　前記非水溶性ポリマーは、前記第１反応性官能基に化学結合可能な第２反応性官能基を含み、
    　前記複合ポリマーにおいて、
    　　前記第１反応性官能基の少なくとも一部と、
    　　前記第２反応性官能基の少なくとも一部とが化学結合している、二次電池セパレータ用コート材原料。     a water-soluble polymer having an SP value of 13.0 (cal/cm 3 ) 1/2 or more;
    SP value 13.0 (cal/cm 3 ) including a composite polymer with a water-insoluble polymer of less than 1/2 ,
    the water-soluble polymer comprises a first reactive functional group;
    the water-insoluble polymer comprises a second reactive functional group capable of chemically bonding to the first reactive functional group;
    In the composite polymer,
    at least a portion of the first reactive functional group;
    A coating material raw material for a secondary battery separator, chemically bonded to at least a part of the second reactive functional group.
  2. 　前記水溶性ポリマーの前記第１反応性官能基が、カルボキシ基を含み、
    　前記非水溶性ポリマーの前記第２反応性官能基が、グリシジル基を含む、請求項１に記載の二次電池セパレータ用コート材原料。     the first reactive functional group of the water-soluble polymer comprises a carboxy group;
    2. The coating material raw material for a secondary battery separator according to claim 1, wherein said second reactive functional group of said water-insoluble polymer contains a glycidyl group.
  3. 　前記水溶性ポリマーは、
    　　（メタ）アクリルアミドに由来する繰り返し単位と、
    　　カルボキシ基含有ビニルモノマーに由来する繰り返し単位とを有し、
    　前記非水溶性ポリマーは、
    　　（メタ）アクリル酸アルキルエステルに由来する繰り返し単位と、
    　　グリシジル基含有ビニルモノマーに由来する繰り返し単位とを有する請求項１に記載の二次電池セパレータ用コート材原料。     The water-soluble polymer is
    (Meth) a repeating unit derived from acrylamide;
    and a repeating unit derived from a carboxy group-containing vinyl monomer,
    The water-insoluble polymer is
    (Meth) a repeating unit derived from an acrylic acid alkyl ester;
    2. The coating material raw material for a secondary battery separator according to claim 1, which has a repeating unit derived from a glycidyl group-containing vinyl monomer.
  4. 　前記水溶性ポリマーおよび前記非水溶性ポリマーの総量１００質量部に対して、
    　前記水溶性ポリマーが、５０質量部以上９９質量部以下であり、
    　前記非水溶性ポリマーが、１質量部以上５０質量部以下である、請求項１に記載の二次電池セパレータ用コート材原料。     With respect to 100 parts by mass of the total amount of the water-soluble polymer and the water-insoluble polymer,
    The water-soluble polymer is 50 parts by mass or more and 99 parts by mass or less,
    The coating material raw material for a secondary battery separator according to claim 1, wherein the water-insoluble polymer is 1 part by mass or more and 50 parts by mass or less.
  5. 　前記水溶性ポリマーの重量平均分子量が、１万以上２０万以下である、請求項１に記載の二次電池セパレータ用コート材原料。 The coating material raw material for a secondary battery separator according to claim 1, wherein the water-soluble polymer has a weight average molecular weight of 10,000 or more and 200,000 or less.
  6. 　前記水溶性ポリマーのガラス転移温度が、１５０℃以上２４０℃以下である、請求項１に記載の二次電池セパレータ用コート材原料。 The coating material raw material for a secondary battery separator according to claim 1, wherein the water-soluble polymer has a glass transition temperature of 150°C or higher and 240°C or lower.
  7. 　前記非水溶性ポリマーのガラス転移温度が、－４０℃以上５０℃以下である、請求項１に記載の二次電池セパレータ用コート材原料。 The coating material raw material for a secondary battery separator according to claim 1, wherein the water-insoluble polymer has a glass transition temperature of -40°C or higher and 50°C or lower.
  8. 　請求項１に記載の二次電池セパレータ用コート材原料を含むことを特徴とする、二次電池セパレータ用コート材。 A coating material for a secondary battery separator, comprising the coating material raw material for a secondary battery separator according to claim 1.
  9. 　さらに、無機充填剤と分散剤とを含む
    　ことを特徴とする、請求項８に記載の二次電池セパレータ用コート材。     The coating material for a secondary battery separator according to claim 8, further comprising an inorganic filler and a dispersant.
  10. 　多孔膜と、
    　前記多孔膜の少なくとも片面に配置される請求項８に記載の二次電池セパレータ用コート材の塗布膜と
    　を備えることを特徴とする、二次電池セパレータ。     a porous membrane;
    A secondary battery separator comprising: a coating film of the coating material for a secondary battery separator according to claim 8 arranged on at least one side of the porous film.
  11. 　多孔膜を準備する工程、および、
    　前記多孔膜の少なくとも片面に、請求項８に記載の二次電池セパレータ用コート材を塗布する工程を備える
    　ことを特徴とする、二次電池セパレータの製造方法。     preparing a porous membrane; and
    A method for manufacturing a secondary battery separator, comprising: applying the coating material for a secondary battery separator according to claim 8 to at least one side of the porous membrane.
  12. 　正極と、負極と、前記正極および前記負極の間に配置される請求項１０に記載される二次電池セパレータとを備えることを特徴とする、二次電池。
          A secondary battery comprising a positive electrode, a negative electrode, and a secondary battery separator according to claim 10 disposed between said positive electrode and said negative electrode.
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JP2013161784A (en) * 2012-02-06 2013-08-19 Samsung Sdi Co Ltd Lithium secondary battery
WO2018173717A1 (en) * 2017-03-24 2018-09-27 日本ゼオン株式会社 Binder composition for nonaqueous secondary batteries and slurry composition for nonaqueous secondary batteries
JP2019192339A (en) * 2018-04-18 2019-10-31 三井化学株式会社 Secondary battery separator, secondary battery laminate and wound body including the same, and non-aqueous secondary battery

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Patent Citations (3)

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JP2013161784A (en) * 2012-02-06 2013-08-19 Samsung Sdi Co Ltd Lithium secondary battery
WO2018173717A1 (en) * 2017-03-24 2018-09-27 日本ゼオン株式会社 Binder composition for nonaqueous secondary batteries and slurry composition for nonaqueous secondary batteries
JP2019192339A (en) * 2018-04-18 2019-10-31 三井化学株式会社 Secondary battery separator, secondary battery laminate and wound body including the same, and non-aqueous secondary battery

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