Classifications

• • H—ELECTRICITY
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  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
  • H01M4/622—Binders being polymers
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  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
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  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/12—Esters of monohydric alcohols or phenols
  • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
  • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
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  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
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  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
  • C08F265/06—Polymerisation of acrylate or methacrylate esters on to polymers thereof
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  • C08F279/00—Macromolecular compounds obtained by polymerising monomers on to polymers of monomers having two or more carbon-to-carbon double bonds as defined in group C08F36/00
  • C08F279/02—Macromolecular compounds obtained by polymerising monomers on to polymers of monomers having two or more carbon-to-carbon double bonds as defined in group C08F36/00 on to polymers of conjugated dienes
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  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F287/00—Macromolecular compounds obtained by polymerising monomers on to block polymers
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  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D151/00—Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers
  • C09D151/003—Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds
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  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D151/00—Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers
  • C09D151/006—Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers grafted on to block copolymers containing at least one sequence of polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • H—ELECTRICITY
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  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
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  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
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  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0566—Liquid materials
• • H—ELECTRICITY
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  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/04—Processes of manufacture in general
  • H01M4/0402—Methods of deposition of the material
  • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
• • H—ELECTRICITY
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  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• • 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
• • 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
• • H—ELECTRICITY
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  • 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
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/417—Polyolefins
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  • 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
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  • 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
  • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
• • H—ELECTRICITY
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  • 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
  • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
• • H—ELECTRICITY
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  • 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
  • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/20—Applications use in electrical or conductive gadgets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2207/00—Properties characterising the ingredient of the composition
  • C08L2207/53—Core-shell polymer
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/021—Physical characteristics, e.g. porosity, surface area
• • 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 binder composition for a secondary battery, a slurry composition for a secondary battery, a functional layer for a secondary battery, a separator for a secondary battery, an electrode for a secondary battery, and a secondary battery.
• Non-aqueous secondary batteries such as lithium-ion secondary batteries are small and lightweight, have high energy density, and can be repeatedly charged and discharged, and are used in a wide range of applications.
• a secondary battery generally includes a battery member such as an electrode (positive electrode and negative electrode) and a separator that separates the positive electrode and the negative electrode to prevent a short circuit between the positive electrode and the negative electrode.
• a separator for a secondary battery a separator having an adhesive layer containing a binder and a porous film layer containing the binder and non-conductive particles as functional particles on a separator base material is provided. Is used. Further, as the electrode of the secondary battery, an electrode having an electrode mixture layer containing a binder and an electrode active material particle as a functional particle on the current collector, or an electrode mixture on the current collector. An electrode further provided with the above-mentioned adhesive layer or porous film layer is used on the electrode base material provided with the layer.
• the problem of precipitation of lithium metal is known as a problem peculiar to the lithium ion secondary battery.
• Precipitation of lithium metal on the negative electrode during charging and discharging can cause a short circuit, and it is required to be strictly suppressed from the viewpoint of improving safety and reliability.
• the present inventor has completed the present invention by conducting diligent studies focusing on the suppression of migration of the binder, with the aim of solving the above problems.
• the present invention is an object of the present invention to advantageously solve the above problems, and is a binder composition for a secondary battery containing a polymer and a solvent.
• the polymer is a core-shell type particle having a core portion made of the polymer (a1) and a shell portion made of the polymer (a2).
• the polymer (a2) contains a monofunctional unsaturated carboxylic acid ester monomer unit of 50.0% by mass or more and 89.9% by mass or less, a monofunctional unsaturated carboxylic acid monomer unit and a monofunctional unsaturated sulfonic acid monomer.
• the "core-shell type particle” refers to a particle having a multi-layer structure (core-shell structure) in which the shell portion covers the surface of the core portion.
• Constaining a monomer unit means that "a monomer-derived repeating unit is contained in the polymer obtained by using the monomer”.
• the "unsaturated carboxylic acid ester monomer” refers to an unsaturated carboxylic acid ester containing an ethylenically unsaturated bond.
• the “unsaturated carboxylic acid monomer” refers to an unsaturated carboxylic acid containing an ethylenically unsaturated bond, and includes an anhydride thereof.
• the "monofunctional unsaturated carboxylic acid ester monomer” refers to an unsaturated carboxylic acid ester containing one ethylenically unsaturated bond.
• the "monofunctional unsaturated carboxylic acid monomer” refers to an unsaturated carboxylic acid containing one ethylenically unsaturated bond, and includes an anhydride thereof.
• the “monofunctional unsaturated sulfonic acid monomer” refers to an unsaturated sulfonic acid containing one ethylenically unsaturated bond, and includes an anhydride thereof.
• the following is presumed as a mechanism for obtaining excellent adhesion between the layer obtained by using the binder composition and the base material.
• the solubilized shell portion with the expanded molecular chain suppresses the migration of core-shell type particles, which are binders, in the production of layers (for example, electrode mixture layer, porous membrane layer, etc.) in a secondary battery. Guessed. Then, it is presumed that by suppressing this migration, excellent adhesion can be obtained between the layer obtained by using the binder composition and the base material.
• one or more monomers selected from a monofunctional unsaturated carboxylic acid ester monomer unit, a monofunctional unsaturated carboxylic acid monomer unit, and a monofunctional unsaturated sulfonic acid monomer unit. If only the unit is introduced, when the secondary battery is assembled and the electrolytic solution is injected, the insoluble amount of the electrolytic solution of the core-shell type particles as the binder is reduced, and the cycle characteristics of the secondary battery may be deteriorated. In the present invention, it is presumed that the decrease in the insoluble amount of the electrolytic solution is suppressed by introducing a monomer unit having two or more vinyl functional groups in a predetermined amount.
• one or more monomer units selected from a monomer unit having two or more vinyl functional groups, a monofunctional unsaturated carboxylic acid monomer unit, and a monofunctional unsaturated sulfonic acid monomer unit are selected from a monomer unit having two or more vinyl functional groups, a monofunctional unsaturated carboxylic acid monomer unit, and a monofunctional unsaturated sulfonic acid monomer unit. It is presumed that by setting the ratio to and within a predetermined range, both suppression of migration due to the expansion of the molecular chain in the shell portion into the aqueous phase and suppression of reduction in the amount of electrolyte insoluble can be obtained. ..
• the secondary battery using the binder composition of the present invention excellent adhesion between the layer obtained by using the binder composition and the base material can be obtained, and the charge / discharge cycle is repeated. It is presumed that the decrease in adhesion is suppressed even after this. Then, it is presumed that the secondary battery using the binder composition of the present invention exhibits good cycle characteristics.
• a lithium ion secondary battery in which the precipitation of lithium metal is remarkably suppressed can be obtained. It is presumed that the suppression of lithium metal precipitation is due to the fact that the core-shell type particles, which are the binder, have excellent liquid retention properties of the electrolytic solution, and the uneven distribution is prevented by suppressing migration.
• the present invention relates to the above-mentioned binder composition for a secondary battery, wherein the amount of tetrahydrofuran (THF) insoluble in the polymer (a1) is 40% or more and 97% or less.
• THF tetrahydrofuran
• the polymer (a1) having a THF insoluble content within the above range for the core portion an appropriate elastic modulus is imparted to the core-shell type particles which are the binder, and good film forming property between the particles can be obtained.
• the adhesion between the substrate and the substrate can be sufficiently improved.
• the amount of THF insoluble can be measured by the method described in the examples of the present specification.
• the present invention relates to the above-mentioned binder composition for a secondary battery, wherein the ratio of the mass of the polymer (a1) to the mass of the polymer (a2) is 95/5 or less and 5/95 or more.
• the core-shell type particles in which the ratio of the mass of the polymer (a1) to the mass of the polymer (a2) is within the above range, the core portion is sufficiently covered with the shell portion, and migration can be sufficiently suppressed.
• the present invention relates to the above-mentioned binder composition for a secondary battery, wherein the core-shell type particles have an inertial radius of 10 nm or more and 1000 nm or less.
• the shell portion has a sufficient spread of molecular chains, migration can be sufficiently suppressed, and the number of particles having excellent liquid retention of the electrolytic solution is relative. This is advantageous because the uneven distribution of the electrolytic solution is suppressed, and especially when used in a lithium ion secondary battery, the precipitation of lithium metal can be sufficiently prevented.
• the radius of inertia can be measured by the method described in the examples herein.
• the present invention relates to a slurry composition for a secondary battery having the above-mentioned binder composition for a secondary battery.
• the present invention relates to the above-mentioned slurry composition for a secondary battery containing non-conductive particles, and also to the above-mentioned slurry composition for a secondary battery containing an electrode active material.
• the present invention relates to a functional layer for a secondary battery formed by using the above slurry composition for a secondary battery.
• the present invention relates to a secondary battery separator having a secondary battery functional layer formed on a separator base material using the secondary battery slurry composition containing the above-mentioned non-conductive particles, and also collects electricity.
• the present invention relates to a secondary battery electrode having a secondary battery functional layer formed on the body using the secondary battery slurry composition containing the above-mentioned electrode active material particles.
• the present invention relates to a secondary battery provided with the above-mentioned functional layer for the secondary battery.
• the present invention relates to a secondary battery including the above-mentioned separator for a secondary battery, and also relates to a secondary battery including the above-mentioned electrode for a secondary battery.
• the binder composition for a secondary battery of the present invention in the production of separators, electrodes and the like of a secondary battery, excellent adhesion between the layer obtained by using the binder composition and the base material can be obtained. , Can provide a secondary battery with good cycle characteristics.
• the binder composition for a secondary battery of the present invention it is suppressed that the adhesiveness is lowered even after repeating the charge / discharge cycle.
• the precipitation of lithium metal is remarkably suppressed.
• the binder composition for a secondary battery of the present invention is used for manufacturing a secondary battery (for example, a non-aqueous secondary battery such as a lithium ion secondary battery), and is used, for example, for the secondary battery of the present invention. It can be used to prepare a slurry composition.
• the slurry composition for a secondary battery of the present invention has an arbitrary function of transferring, reinforcing or adhering electrons in a secondary battery (for example, a non-aqueous secondary battery such as a lithium ion secondary battery). It can be used for forming a functional layer (for example, an electrode mixture layer, a porous film layer, an adhesive layer).
• the functional layer for a secondary battery of the present invention is formed from the slurry composition for a secondary battery of the present invention.
• the separator for a secondary battery and the electrode for a secondary battery of the present invention include the functional layer for the secondary battery of the present invention.
• the secondary battery of the present invention (for example, a non-aqueous secondary battery such as a lithium ion secondary battery) is at least one of the functional layer for the secondary battery, the separator for the secondary battery and the electrode for the secondary battery of the present invention. It is equipped with a battery.
• the binder composition for a secondary battery of the present invention contains a polymer and a solvent.
• the binder composition for a secondary battery of the present invention contains a polymer.
• the polymer is a core-shell type particle having a core portion made of the polymer (a1) and a shell portion made of the polymer (a2).
• the core portion made of the polymer (a1) is not particularly limited, and a known polymer can be used as the binder.
• THF insoluble amount of polymer (a1)- The amount of THF insoluble in the polymer (a1) is preferably 40% or more, and preferably 97% or less.
• the amount of THF insoluble is more preferably 45% or more, further preferably 50% or more, still more preferably 95% or less, still more preferably 93% or less.
• the amount of THF insoluble can be adjusted according to the type and amount of the monomer used in the preparation of the polymer (a1).
• An aqueous dispersion of a polymer having the same composition as that of the polymer (a1) may be prepared, and the amount of THF-insoluble content thereof may be measured to obtain the amount of THF-insoluble content of the polymer (a1).
• the polymer (a1) can be a polymer having an arbitrary composition, and examples thereof include a polymer containing an unsaturated carboxylic acid ester monomer unit and an unsaturated carboxylic acid monomer unit.
• the unsaturated carboxylic acid ester capable of forming the unsaturated carboxylic acid ester monomer unit is not particularly limited, and is, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate. , Pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate such as 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate, etc.
• alkyl ester of 20 or less preferably an alkyl ester having 1 to 10 carbon atoms
• Octyl methacrylate such as methacrylate, heptyl methacrylate and 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, stearyl methacrylate and other methacrylic acid alkyl esters (for example, alkyl esters having 1 to 20 carbon atoms). Yes, preferably an alkyl ester having 1 or more and 10 or less carbon atoms) and the like.
• methyl methacrylate, ethyl methacrylate, and n-butyl acrylate are preferable, and a combination of methyl methacrylate and n-butyl acrylate is more preferable, from the viewpoint of polymerization stability and core-shell structure formation.
• the unsaturated carboxylic acid ester monomer unit may be used alone or in any combination of two or more kinds.
• the unsaturated carboxylic acid that can form an unsaturated carboxylic acid monomer is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid.
• the unsaturated dicarboxylic acid may be anhydrous. Of these, acrylic acid, methacrylic acid, and itaconic acid are more preferable, and acrylic acid and methacrylic acid are even more preferable, from the viewpoint of polymerization stability and core-shell structure formation.
• the unsaturated carboxylic acid ester monomer unit is preferably 20.0% by mass or more, more preferably 30.0% by mass or more, and also. , It is preferably 99.9% by mass or less, and more preferably 90.0% by mass or less.
• the shell portion can sufficiently cover the core portion and be immobilized on the core portion, and foaming of the binder composition or the slurry composition can be suppressed.
• the insoluble amount in the electrolytic solution is sufficient, and good cycle characteristics can be obtained.
• the unsaturated carboxylic acid monomer unit is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, and preferably 5.0% by mass or less, more preferably 4. It is 5.5% by mass or less. If it is at least the above lower limit, the core-shell type particles are sufficiently stabilized and good adhesion to the substrate can be provided, and if it is at least the above upper limit, the shell portion presses the core portion. It can be sufficiently coated, and foaming of the binder composition and the slurry composition can be suppressed.
• the polymer containing the unsaturated carboxylic acid ester monomer unit and the unsaturated carboxylic acid monomer unit can contain other monomer units.
• the monomer capable of forming other monomer units include aliphatic groups such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene) and 2,3-dimethyl-1,3-butadiene. Conjugated diene; styrene, styrene sulfonic acid and salts thereof, aromatic vinyl such as ⁇ -methylstyrene, butoxystyrene, vinylnaphthalene and the like can be mentioned.
• the other monomer unit can be 10.0% by mass or less.
• an aliphatic conjugated diene monomer unit can be contained as another monomer unit.
• the polymer (a1) can be composed of an unsaturated carboxylic acid ester monomer unit, an unsaturated carboxylic acid monomer unit, and an aliphatic conjugated diene monomer unit.
• the aliphatic conjugated diene monomer can be 5.0% by mass or more, preferably 10.0% by mass or more, and can be 50.0% by mass or less, which is preferable. Is 45.0% by mass or less.
• the above examples and suitable ranges apply to the amounts of unsaturated carboxylic acid ester monomer units and unsaturated carboxylic acid monomer units.
• polymer (a1) examples include, in addition to the above-mentioned polymers, aliphatic conjugated diene polymers such as polybutadiene and polyisoprene, styrene-butadiene polymer (SBR), styrene-butadiene-styrene polymer (SBS) and the like.
• aliphatic conjugated diene polymers such as polybutadiene and polyisoprene
• SBR styrene-butadiene polymer
• SBS styrene-butadiene-styrene polymer
• Aromatic vinyl / aliphatic conjugated diene copolymers, vinyl cyanide-conjugated diene copolymers such as acrylonitrile-butadiene polymer (NBR), hydrogenated SBR, hydrogenated NBR and the like can be used.
• NBR acrylonitrile-butadiene polymer
• NBR acrylonitrile
• the shell portion is made of a polymer (a2), and the polymer (a2) contains a monofunctional unsaturated carboxylic acid ester monomer unit of 50.0% by mass or more and 89.9% by mass or less, and a monofunctional unsaturated carboxylic acid single amount.
• One or more monomer units selected from body units and monofunctional unsaturated sulfonic acid monomer units 10.0% by mass or more and 49.9% by mass or less, monomer units having two or more vinyl functional groups 0 Includes 0.1% by mass or more and 10.0% by mass or less, and 5.0% by mass or less of aromatic vinyl monomer units.
• the content of each monomer unit is based on 100.0% by mass of the polymer (a2).
• the polymer (a2) is selected from the monofunctional unsaturated carboxylic acid monomer unit and the monofunctional unsaturated sulfonic acid monomer unit with respect to 1 mol of the monomer unit having two or more vinyl functional groups.
• One or more monomer units are 0.1 mol or more and 15,000 mol or less.
• the shell portion does not sufficiently cover the core portion, and immobilization to the core portion is insufficient, resulting in a binder composition or a binder composition.
• the slurry composition tends to foam.
• the monofunctional unsaturated carboxylic acid ester monomer exceeds 89.9% by mass, the shell portion becomes difficult to dissolve in water, the molecular chain of the shell portion does not spread, the migration suppressing ability decreases, and adhesion occurs. It becomes difficult to improve sex.
• One or more monomer units selected from a monofunctional unsaturated carboxylic acid monomer unit and a monofunctional unsaturated sulfonic acid monomer unit (hereinafter, "monofunctional unsaturated carboxylic acid and / or sulfonic acid monomer unit") If it is less than 10.0% by mass, the shell portion becomes difficult to dissolve in water, the molecular chain of the shell portion does not spread, the migration suppressing ability is lowered, and it is difficult to improve the adhesion. become. On the other hand, when the monofunctional unsaturated carboxylic acid and / or the sulfonic acid monomer unit exceeds 49.9% by mass, the shell portion does not sufficiently cover the core portion, and the immobilization to the core portion is insufficient.
• the monofunctional unsaturated carboxylic acid and / or sulfonic acid monomer unit is preferably 13.0% by mass or more, more preferably 16.0% by mass or more, and preferably 49.0% by mass or less. It is more preferably 48.0% by mass or less.
• the monomer unit having two or more vinyl functional groups When the monomer unit having two or more vinyl functional groups is less than 0.1% by mass, the solubility of the core-shell type particles as the binder in the electrolytic solution becomes high, and the function as the binder becomes high. It weakens, and the cycle characteristics and peel strength after the cycle test decrease. Further, since the liquid retention property of the electrolytic solution is lowered, the precipitation of lithium metal cannot be sufficiently suppressed when used in a lithium ion secondary battery.
• the monomer unit having two or more vinyl functional groups exceeds 10.0% by mass, the crosslinked structure in the shell portion increases, the shell portion becomes difficult to dissolve in water, and the molecular chain of the shell portion. Does not spread, the migration suppression ability is reduced, and it becomes difficult to improve the adhesion.
• the monomer unit having two or more vinyl functional groups is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and preferably 8.0% by mass or less. More preferably, it is 3.0% by mass or less.
• the shell portion does not sufficiently cover the core portion, and the binder composition and the slurry composition tend to foam.
• the aromatic vinyl monomer unit is preferably 4.0% by mass or less, more preferably 2.0% by mass or less, and may be 0.0% by mass.
• the polymer (a2) can contain other monomer units as long as the effects of the present invention are not impaired, but is preferably a monofunctional unsaturated carboxylic acid ester monomer unit of 50.0% by mass or more. 89.9% by mass or less, monofunctional unsaturated carboxylic acid and / or sulfonic acid monomer unit 10.0% by mass or more and 49.9% by mass or less, monomer unit having two or more vinyl functional groups 0.1 It is composed of mass% or more and 10.0 mass% or less and an aromatic vinyl monomer unit of 5.0 mass% or less (may be 0.0 mass%).
• the monofunctional unsaturated carboxylic acid and / or the sulfonic acid monomer unit is less than 0.1 mol with respect to 1 mol of the monomer unit having two or more vinyl functional groups, the molecular chain of the shell portion does not spread. , Migration suppression ability is reduced, and it becomes difficult to improve adhesion. Further, when the monofunctional unsaturated carboxylic acid and / or the sulfonic acid monomer unit exceeds 15,000 mol with respect to 1 mol of the monomer unit having two or more vinyl functional groups, the core shell which is a binder is used. The solubility of the mold particles in the electrolytic solution becomes high, the function as a binder is weakened, and the cycle characteristics and the peel strength after the cycle test are lowered.
• the monofunctional unsaturated carboxylic acid and / or sulfonic acid monomer unit is preferably 0.15 mol or more, more preferably 0.25 mol, with respect to 1 mol of the monomer unit having two or more vinyl functional groups. It is 14,000 mol or more, preferably 14,000 mol or less, and more preferably 13,500 mol or less.
• the monofunctional unsaturated carboxylic acid ester capable of forming a monofunctional unsaturated carboxylic acid ester monomer unit can be a mono- or polycarboxylic acid ester, and is preferably a monocarboxylic acid ester from the viewpoint of forming a core-shell structure. Yes, more preferably an acrylic acid ester, a methacrylic acid ester, or the like.
• the ester include an alkyl ester, which can be an alkyl ester having 1 or more and 20 or more carbon atoms from the viewpoint of polymerization stability and core-shell structure formation, and an alkyl ester having 1 or more and 10 or less carbon atoms is preferable.
• octyl acrylate nonyl acrylate such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate and 2-ethylhexyl acrylate.
• the monofunctional unsaturated carboxylic acid ester monomer unit may be used alone or in combination of two or more at any ratio.
• the monofunctional unsaturated carboxylic acid capable of forming a monofunctional unsaturated carboxylic acid monomer unit can be a mono- or polycarboxylic acid, and is preferably a monocarboxylic acid from the viewpoint of expanding the molecular chain of the shell portion. , More preferably acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and even more preferably acrylic acid, methacrylic acid, itaconic acid.
• Examples of the monofunctional unsaturated sulfonic acid capable of forming the monofunctional unsaturated sulfonic acid monomer include vinyl sulfonic acid, p-styrene sulfonic acid, (meth) allyl sulfonic acid, and the like, preferably p-styrene sulfonic acid and the like. Is.
• the monofunctional unsaturated carboxylic acid and / or sulfonic acid monomer unit may be in the form of a salt, for example, an alkali metal salt (Na salt, K salt, etc.), an alkaline earth metal salt (Mg salt, etc.), Examples include ammonium salts.
• a salt for example, an alkali metal salt (Na salt, K salt, etc.), an alkaline earth metal salt (Mg salt, etc.), Examples include ammonium salts.
• the monofunctional unsaturated carboxylic acid and / or sulfonic acid monomer unit may be one of them alone or a combination of two or more at any ratio.
• the "monomer unit having two or more vinyl functional groups” does not include the one corresponding to the "aromatic vinyl monomer unit".
• the number of vinyl functional groups in the monomer unit having two or more vinyl functional groups may be two or more, but from the viewpoint of solubility of the shell portion in water, it is preferably two or more and 10 or less, more preferably. 2 or more and 6 or less.
• Examples of the monomer having two or more vinyl functional groups capable of forming a monomer unit having two or more vinyl functional groups include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), and 2 , 3-Dimethyl-1,3-butadiene or the like aliphatic diene; vinyl ether or allyl ether of unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate, vinyl acrylate, vinyl methacrylate; ethylene glycol dimethacrylate, trimethyl propantriacrylate, Pentaerythritol triacrylate, tetraethylene glycol diacrylate, ethoxylated isocyanuric acid triacrylate, ethoxylate glycerin triaclate, ditrimethylol propanetetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol polyacrylate, dipentaerythrito
• Acrylate ester of polyhydric alcohol, methacrylic acid ester and the like can be mentioned.
• ethylene glycol dimethacrylate, 1,3-butadiene, pentaerythritol tetraacrylate ethoxylated and the like are preferable from the viewpoint of solubility of the shell portion in water.
• the monomer unit having two or more vinyl functional groups may be used alone or in combination of two or more at any ratio.
• the "aromatic vinyl monomer unit” corresponds to either a “monofunctional unsaturated carboxylic acid monomer unit” or a “monofunctional unsaturated sulfonic acid monomer unit”. Things shall not be included.
• examples of the monomer capable of forming an aromatic vinyl monomer include styrene, ⁇ -methylstyrene, butoxystyrene, vinylnaphthalene and the like.
• the aromatic vinyl monomer unit may be used alone or in combination of two or more at any ratio.
• the weight average molecular weight of the polymer (a2) is preferably 10,000 or more, more preferably 30,000 or more, and preferably 10,000,000 or less, more preferably 4,500, It is 000 or less. Within the above range, migration by the shell portion is sufficiently suppressed, good adhesion is obtained, and core-shell type particles, which are binders, are sufficiently dispersed in the binder composition and the slurry composition, resulting in a good cycle. The characteristics can be obtained.
• the weight average molecular weight can be measured by the measuring method described in the examples of the present specification.
• the core-shell type particles have a core portion made of the polymer (a1) and a shell portion made of the polymer (a2).
• the ratio of the mass of the polymer (a1) to the mass of the polymer (a2) ((mass of a1) / (mass of a2)) in the core-shell type particles is preferably 95/5 or less, more preferably 90. It is / 10 or less, more preferably 87/13 or less, preferably 5/95 or more, more preferably 10/90 or more, and even more preferably 13/87 or more.
• the radius of inertia of the core-shell type particles is preferably 10 nm or more, more preferably 30 nm or more, further preferably 50 nm or more, and preferably 1000 nm or less, more preferably 800 nm or less, still more preferable. Is 600 nm or less.
• the method for producing the core-shell type particles is not particularly limited, but an emulsion polymerization method, solution polymerization, bulk polymerization, suspension polymerization and the like are preferable from the viewpoint that core-shell type particles can be easily obtained.
• the monomer forming the polymer (a1) is radically polymerized in an aqueous solvent in the presence of an emulsifier and a polymerization initiator to obtain the polymer (a1), and then further.
• a method of adding a monomer forming the polymer (a2) and polymerizing these can be mentioned. From the viewpoint of covering the outer surface of the core portion with the shell portion, it is preferable that the monomer forming the polymer of the shell portion is divided into a plurality of times or continuously supplied to the polymerization system.
• the emulsifier is not particularly limited, and examples thereof include anionic surfactants such as sodium dodecylbenzene sulfonate and sodium dodecyl sulfate (sodium lauryl sulfate); and cationic surfactants such as octadecylamine acetate.
• anionic surfactants such as sodium dodecylbenzene sulfonate and sodium dodecyl sulfate (sodium lauryl sulfate); and cationic surfactants such as octadecylamine acetate.
• the emulsifier may be used alone or in combination of two or more at any ratio.
• the polymerization initiator is not particularly limited, and for example, peroxides such as t-butylperoxy-2-ethylhexanoate, potassium persulfate, ammonium persulfate, and cumempoxide; 2,2'-azobis (2-). Examples thereof include azo compounds such as methyl-N- (2-hydroxyethyl) -propionamide) and 2,2'-azobis (2-amidinopropane) hydrochloride.
• the polymerization initiator may be used alone or in combination of two or more kinds at any ratio.
• a chain transfer agent can be used for the reaction.
• the chain transfer agent is not particularly limited, and is preferably an alkyl mercaptan, more preferably a t-dodecyl mercaptan.
• Water can be used as the aqueous solvent, and a hydrophilic solvent other than water may be mixed as long as the monomer used for producing core-shell type particles can be dissolved or dispersed.
• the hydrophilic solvent include alcohols such as methanol, ethanol, n-propanol and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; alkyl ethers of polyalkylene glycol; N- Examples thereof include lactam such as methyl-2-pyrrolidone.
• the pH with a basic compound after polymerization it is preferable to adjust the pH with a basic compound after polymerization from the viewpoint of charging the shell portion and expanding the molecular chain by the repulsive force thereof.
• the pH of the reaction solution after polymerization is usually about 0.2 to 6
• adjusting the pH with a basic compound is usually an operation corresponding to neutralization.
• the pH is preferably adjusted to 4 or more and 9 or less from the viewpoint of slurry stability
• the basic compound include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, 2-aminoethanol and 2-.
• Organic amines such as dimethylaminoethanol
• inorganic basic compounds such as ammonia (water), sodium hydroxide, potassium hydroxide, lithium hydroxide; tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydro Examples thereof include quaternary ammonium hydrooxide of oxide.
• inorganic basic compounds such as sodium hydroxide and potassium hydroxide are preferable.
• the basic compounds may be used alone or in combination of two or more at any ratio.
• the core-shell type particles are manufactured so that the ratio of the adjusted viscosity (adjusted viscosity / unadjusted viscosity) to the viscosity before pH adjustment of the binder composition is 1.5 times or more. It is preferably 1.6 times or more, and the upper limit is not particularly limited, but is usually 500 times or less. Within the above range, the shell portion has a sufficient spread of molecular chains, migration is sufficiently suppressed, core-shell type particles as a binder are sufficiently dispersed in the binder composition and the slurry composition, and a good cycle is achieved. The characteristics can be obtained.
• the binder composition for a secondary battery of the present invention contains a solvent.
• the solvent can be an aqueous solvent, and examples thereof include water and a mixed solvent of water and a hydrophilic organic solvent, and water is preferable.
• the aqueous solvent the description (including examples and suitable examples) in the production of core-shell type particles is applied.
• the aqueous solvent used in the production of core-shell type particles can be used as it is.
• binder composition for a secondary battery of the present invention core-shell type particles obtained by an emulsion polymerization method are dispersed in an aqueous solvent as they are, or if necessary, pH adjustment and removal of unreacted monomers are performed. It can be produced by removing the solvent or the like.
• the method for removing the unreacted monomer and removing the solvent is not particularly limited, and examples thereof include heating, distillation under reduced pressure, and a combination thereof.
• the binder composition has an electrolytic solution insoluble amount of preferably 50% or more, more preferably 55% or more.
• the upper limit is 100%, and the amount of insoluble electrolyte may be 100%.
• the core-shell type particles can maintain the core-shell structure, obtain sufficient adhesion, and maintain good cycle characteristics.
• the insoluble amount of the electrolytic solution can be measured by the method described in the examples of the present specification.
• the binder composition can contain a binder other than the core-shell type particles, but the core-shell type particles can be preferably 5 parts by mass or more with respect to 100 parts by mass of the binder, which is preferable. Is 20 parts by mass or more. Only core-shell type particles can be used as the binder.
• the binder other than the core-shell type particles include aromatic conjugated diene polymers such as polybutadiene and polyisoprene, styrene-butadiene polymers (SBR), and styrene-butadiene-styrene polymers (SBS).
• a vinyl cyanide-conjugated diene copolymer such as a group vinyl / aliphatic conjugated diene copolymer or an acrylonitrile-butadiene polymer (NBR), a hydrogenated SBR, a hydrogenated NBR or the like) can be used.
• NBR acrylonitrile-butadiene polymer
• the binder composition further contains components such as a thickener, a wetting agent, a conductive auxiliary agent, a reinforcing material, a leveling agent, an electrolyte solution additive, and a defoaming agent, as long as the effects of the present invention are not impaired. May be good. These components may be used alone or in combination of two or more at any ratio.
• the solid content concentration of the binder composition is not particularly limited, and can be, for example, 5% by mass or more and 70% by mass or less.
• the slurry composition for a secondary battery of the present invention is a composition used for forming an arbitrary functional layer in a secondary battery (for example, a non-aqueous secondary battery such as a lithium ion secondary battery), and the present invention. It contains a binder composition for a secondary battery of the above, and can further contain functional particles and other components. Since the binder composition for a secondary battery of the present invention is contained, a functional layer having excellent adhesion can be obtained by applying the slurry composition for a secondary battery of the present invention on a substrate, for example, and drying it. can.
• the amount of the binder composition for a secondary battery of the present invention in the slurry composition is not particularly limited and can be set according to the functional layer.
• the binder composition has a solid content equivalent to 100 parts by mass of the electrode active material particles (core-shell type particles and any binder).
• the amount can be 0.5 parts by mass or more and 15 parts by mass or less.
• the binder composition has a binder composition (core-shell type particles and any binder) equivalent to 100 parts by mass of non-conductive particles, which is equivalent to 0.
• the amount can be 5 parts by mass or more and 30 parts by mass or less.
• the slurry composition can contain functional particles depending on the desired functional layer.
• the functional layer is an electrode mixture layer, electrode active material particles can be mentioned, and when the functional layer is a porous membrane layer, non-conductive particles can be mentioned.
• Electrode active material particles are not particularly limited, and examples thereof include particles made of known electrode active materials used in secondary batteries. For example, with respect to the electrode mixture layer of the lithium ion secondary battery, particles made of the following electrode active materials can be mentioned.
• the positive electrode active material blended in the positive electrode mixture layer of the positive electrode of the lithium ion secondary battery is not particularly limited, and examples thereof include compounds containing a transition metal, such as transition metal oxides, transition metal sulfides, and lithium. Examples include composite metal oxides with transition metals.
• examples of the transition metal include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Mo.
• LiFePO 4 olivine-type lithium iron phosphate
• LiMnPO 4 olivine-type lithium manganese phosphate
• the positive electrode active material may be used alone or in combination of two or more at any ratio.
• the negative electrode active material blended in the negative electrode mixture layer of the negative electrode of the lithium ion secondary battery is not particularly limited, and examples thereof include a carbon-based negative electrode active material, a metal-based negative electrode active material, and a negative electrode active material combining these.
• the carbon-based negative electrode active material refers to an active material having carbon as a main skeleton into which lithium can be inserted (also referred to as “dope”), and includes, for example, coke, mesocarbon microbeads (MCMB), and mesophase pitch.
• Carbon-based carbon fibers thermally decomposed vapor-grown carbon fibers, phenolic resin calcined material, polyacrylonitrile-based carbon fiber, pseudoisotropic carbon, furfuryl alcohol resin calcined material (PFA), hard carbon and other carbonaceous materials; natural graphite, Examples thereof include a graphite material such as artificial graphite.
• the metal-based negative electrode active material is an active material containing a metal, and usually contains an element into which lithium can be inserted in the structure, and the theoretical electric capacity per unit mass when lithium is inserted is 500 mAh / g or more.
• Is an active material for example, a lithium metal, a single metal capable of forming a lithium alloy (for example, Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni, P, Pb, Sb, Si, Sn. , Sr, Zn, Ti, etc.) and their oxides, sulfides, nitrides, silicides, carbides, phosphates and the like. Further, oxides such as lithium titanate can be mentioned.
• the negative electrode active material may be used alone or in combination of two or more at any ratio.
• Non-conductive particles are not particularly limited, and examples thereof include known non-conductive particles used in a secondary battery.
• the non-conductive particles may be inorganic fine particles or organic fine particles, but inorganic fine particles are usually used. Of these, a material that exists stably in the usage environment of the secondary battery and is electrochemically stable is preferable. From this point, examples of the non-conductive particles include aluminum oxide (alumina), hydrated aluminum oxide (bemite), silicon oxide, magnesium oxide (magnesia), calcium oxide, titanium oxide (titania), BaTIO 3 , and ZrO.
• Oxide particles such as alumina-silica composite oxide; nitride particles such as aluminum nitride and boron nitride; covalently bonded crystal particles such as silicon and diamond; sparingly soluble ions such as barium sulfate, calcium fluoride and barium fluoride Crystalline particles; clay fine particles such as talc and montmorillonite are preferable. These particles may be subjected to element substitution, surface treatment, solid solution formation, etc., if necessary.
• the non-conductive particles may be used alone or in combination of two or more kinds at any ratio.
• the slurry composition may contain other components as long as the effects of the present invention are not impaired.
• the description in the binder composition (including examples and preferred examples) is applied.
• the other components may be used alone or in combination of two or more at any ratio.
• the method for producing the slurry composition is not particularly limited.
• the binder composition, the electrode active material particles and other components used as necessary are mixed in the presence of a solvent to produce a slurry composition. can do.
• the binder composition, non-conductive particles and other components used as necessary can be mixed in the presence of a solvent to produce a slurry composition. can.
• the binder composition can be used as it is or diluted with a solvent as a slurry composition, or the binder composition and other components used as necessary may be used.
• the slurry composition can also be produced by mixing in the presence of a solvent.
• the solvent used in the production of the slurry composition also includes the solvent in the binder composition.
• the solvent is not particularly limited, and examples thereof include water, alcohol, and ketone.
• the mixing method is not particularly limited, and can be carried out using a known stirrer, disperser or the like.
• the functional layer for a secondary battery of the present invention is a layer that has a function of transferring, reinforcing or adhering electrons in a secondary battery (for example, a non-aqueous secondary battery such as a lithium ion secondary battery).
• a secondary battery for example, a non-aqueous secondary battery such as a lithium ion secondary battery.
• an electrode mixture layer that transfers electrons through an electrochemical reaction, a porous film layer that improves heat resistance and strength, an adhesive layer that improves adhesiveness, and the like can be mentioned.
• the functional layer of the present invention is formed from the slurry composition for a secondary battery of the present invention, and can be formed, for example, by applying the slurry composition to, for example, a substrate or more and drying it. Since the slurry composition for a secondary battery of the present invention contains the binder composition for a secondary battery of the present invention, excellent adhesion can be obtained between the functional layer formed from the slurry composition and the base material.
• the base material on which the slurry composition is applied is not particularly limited.
• a current collector may be used as a base material, and the slurry composition may be applied onto the current collector and dried to form the layer.
• a separator base material or an electrode base material may be used as a base material, and the slurry composition may be applied onto the base material and dried to form the layer.
• the slurry composition is applied to the surface of the release base material and dried to form a functional layer, the release base material is peeled off, and the functional layer peeled off from the release base material is used as a self-supporting film for manufacturing a secondary battery. You can also do it.
• the current collector is not particularly limited, and a material having electrical conductivity and electrochemical durability can be used, for example, iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, and the like. Examples thereof include a current collector made of gold, platinum and the like. Of these, copper foil is particularly preferable as the current collector used for the negative electrode. Further, as the current collector used for the positive electrode, an aluminum foil is particularly preferable.
• the material used for the current collector may be a single material or a combination of two or more kinds in any ratio.
• the separator base material is not particularly limited, and examples thereof include known separator base materials such as an organic separator base material.
• the organic separator base material is a porous member made of an organic material, and examples thereof include a microporous film or a non-woven fabric containing a polyolefin resin such as polyethylene and polypropylene, and an aromatic polyamide resin. From the viewpoint of excellent strength, polyethylene microporous membranes and non-woven fabrics are preferable.
• the electrode base material (positive electrode base material and negative electrode base material) is not particularly limited, and examples thereof include an electrode base material in which an electrode mixture layer containing electrode active material particles and a binder is formed on the above-mentioned current collector. Be done.
• the electrode active material particles and the binder contained in the electrode mixture layer are not particularly limited, and the binder material other than the electrode active material particles described in the slurry composition and the core-shell type particles described in the binder composition is not particularly limited. Can be used.
• the functional layer of the present invention may be used as the electrode mixture layer in the electrode base material.
• the method for forming the functional layer on the base material such as the current collector, the separator base material, and the electrode base material is not particularly limited, and examples thereof include the following. 1) A method of applying the slurry composition of the present invention to the surface of a base material (in the case of an electrode base material, the surface on the electrode mixture layer side) and then drying; 2) A method of immersing a base material in the slurry composition of the present invention and then drying it; and 3) applying the slurry composition of the present invention on a release base material and drying to produce a functional layer. A method of transferring the obtained functional layer to the surface of a substrate.
• the method 1) above is preferable because it is easy to control the layer thickness of the functional layer.
• the method of 1) is a step of applying the slurry composition on the base material (coating step) and a step of drying the slurry composition applied on the base material to form a functional layer (drying). Step) is included.
• the method of applying the slurry composition onto the substrate is not particularly limited, and examples thereof include a doctor blade method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method.
• the method for drying the slurry composition on the substrate is not particularly limited, and a known method can be used. For example, drying by warm air, hot air, low humidity air, vacuum drying, and drying by irradiation with infrared rays or electron beams can be mentioned.
• an electrode mixture layer As a functional layer, it is preferable to apply pressure treatment to the electrode mixture layer using a mold press, a roll press, or the like after the drying step.
• the secondary battery of the present invention (for example, a non-aqueous secondary battery such as a lithium ion secondary battery) includes a positive electrode, a negative electrode, a separator and an electrolytic solution, and at least one of the positive electrode, the negative electrode and the separator is the secondary battery of the present invention. It has a functional layer for batteries.
• the secondary battery of the present invention can also be manufactured by using the separator for the secondary battery of the present invention and / or the electrode for the secondary battery of the present invention for one or both of the positive electrode and the negative electrode.
• the positive electrode, negative electrode and separator which do not have the functional layer for the secondary battery of the present invention are not particularly limited, and known positive electrodes, negative electrodes and separators can be used.
• the electrolytic solution is not particularly limited, and examples thereof include an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent.
• the supporting electrolyte used in the lithium ion secondary battery include lithium salts, for example, LiPF 6, LiAsF 6, LiBF 4, LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi and the like.
• LiPF 6 , LiClO 4 , and CF 3 SO 3 Li are preferable because they are easily dissolved in a solvent and show a high degree of dissociation.
• the electrolyte may be used alone or in combination of two or more at any ratio. Normally, the more the supporting electrolyte with a higher degree of dissociation is used, the higher the lithium ion conductivity tends to be. Therefore, the lithium ion conductivity can be adjusted depending on the type of the supporting electrolyte.
• Organic solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte.
• Organic solvents used in lithium ion secondary batteries include dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), ethyl methyl carbonate (EMC), and vinylene.
• Carbonates such as carbonate (VC); esters such as ⁇ -butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide can be mentioned.
• a mixed solution of these solvents may be used.
• carbonates are preferable because they have a high dielectric constant and a wide stable potential region.
• the lower the viscosity of the solvent used the higher the lithium ion conductivity tends to be. Therefore, the lithium ion conductivity can be adjusted depending on the type of solvent.
• the concentration of the electrolyte in the electrolytic solution can be adjusted as appropriate.
• Known additives may be added to the electrolytic solution.
• a positive electrode and a negative electrode are overlapped with each other via a separator, and if necessary, they are rolled or folded into a battery container, and an electrolytic solution is injected into the battery container to seal the battery. It can be manufactured by doing so.
• at least one of the positive electrode, the negative electrode, and the separator is provided with the functional layer for the secondary battery of the present invention.
• an expanded metal, a fuse, an overcurrent prevention element such as a PTC element, a lead plate, or the like may be placed in the battery container to prevent an increase in pressure inside the battery and overcharge / discharge.
• the shape of the battery is not particularly limited, and examples thereof include a coin type, a button type, a sheet type, a cylindrical type, a square type, and a flat type.
• a polymer solution (pH 8.0) of the shell part alone is prepared, and the weight average molecular weight thereof is measured by gel permeation chromatography (GPC), and the weight average molecular weight of the shell part is measured. And said.
• the method for preparing the polymer solution with the shell portion alone is as described later. The measurement was performed as follows. First, a polymer of the shell portion alone is added to about 5 mL of the eluent so that the solid content concentration is about 0.5 g / L, a stirrer is added at room temperature (25 ° C.), and 300 rpm using a magnetic stirrer. Was stirred for 10 minutes to dissolve.
• the binder composition is applied onto a base material made of Teflon (registered trademark) and dried for 24 hours in an environment with a relative humidity of 50% and a temperature of 23 ° C to 25 ° C. Then, a film was formed to a thickness of 0.5 ⁇ 0.3 mm. The formed film was dried in a vacuum dryer at a temperature of 60 ° C. for 10 hours, and then cut into 2 mm square pieces to obtain film pieces, and the obtained film pieces were precisely weighed. (Mass W 1 )
• solvent ratio ethylene carbonate
• EMC ethylmethyl carbonate
• the film piece was taken out from the container using tweezers, placed in another container, and 10 mL of diethyl carbonate was added. After confirming that the entire film piece was immersed in the liquid, the film was washed by leaving it at a temperature of 25 ° C. for 2 hours. Further, the film piece was taken out from the container using tweezers, placed in another container, and 10 mL of ethanol was added. After confirming that the entire film piece was immersed in the liquid, the film was washed by leaving it at a temperature of 25 ° C. for 2 hours. The film pieces were removed, placed on a Kimwipe and dried in a draft for 2 hours. Further, this film piece was placed in a vacuum dryer, reduced in pressure to 25 ° C. gauge pressure ⁇ 0.09 MPa or less, dried for 2 hours or more, and finely weighed. (Mass W 2 )
• Viscosity Ratio of Binder Composition Before and After Neutralization The viscosity was measured using a B-type viscometer under the conditions of a temperature of 25 ° C., a spindle rotation speed of 60 rpm, and a spindle rotation time of 60 seconds.
• the unneutralized solution after polymerization was diluted with ion-exchanged water to a solid content concentration of 10%, and the viscosity was measured. (Viscosity ⁇ 1 )
• an alkaline aqueous solution was added to neutralize the solution to pH 8.0.
• the solid content concentration was adjusted to 10%, and the viscosity after neutralization was measured.
• THF insoluble amount (mass%) (w 1 / w 0 ) ⁇ 100
• the inertial radius is the Field-Flow Fractionation (field flow fractionation, hereinafter “FFF”) to which a Multi angle light scattering (multi-angle light scattering, hereinafter “MALS”) detector is connected. ”)
• FFF Field-Flow Fractionation
• MALS Multi angle light scattering
• the FFF device is a device capable of passing a sample solution through a gap (channel) of 100 ⁇ m or more and 500 ⁇ m or less and adding a field when passing through the channel.
• Peel strength of the electrode A rectangular test piece having a length of 100 mm and a width of 10 mm was cut out from the electrode (negative electrode or positive electrode). The test piece was fixed to the test table with the electrode mixture layer surface facing up. After attaching cellophane tape (specified in JIS Z1522) to the surface of the electrode mixture layer of the fixed test piece, the cellophane tape was peeled off from one end of the test piece at a speed of 50 mm / min in the 180 ° direction. The stress at the time was measured. The same measurement was performed 5 times, and the average value was taken as the peel strength and judged according to the following criteria.
• cellophane tape specified in JIS Z1522
• Capacity retention rate C 3 (%) (C 2 / C 0 ) x 100
• a rectangular test piece having a length of 100 mm and a width of 10 mm was cut out from the obtained electrode (negative electrode or positive electrode).
• the test piece was fixed to the test table with the electrode mixture layer surface facing up.
• cellophane tape (specified in JIS Z1522)
• the cellophane tape was peeled off from one end of the test piece at a speed of 50 mm / min in the 180 ° direction.
• the stress at the time was measured. The same measurement was performed 5 times, and the average value was taken as the peel strength and judged according to the following criteria.
• Peel strength standard of electrode (positive or negative) A: Peel strength is 4N / m or more B: Peel strength is 3N / m or more and less than 4N / m C: Peel strength is 2N / m or more and less than 3N / m D: Peel strength is Separators of less than 2 N / m were also recovered from the cell after the cycle characteristic test, test pieces were prepared in the same manner, and the stress was measured in the same manner as in (8) the peel strength test of the separator coating layer.
• Separator peel strength standard A Peel strength is 40 N / m or more
• B Peel strength is 15 N / m or more and less than 40 N / m
• C Peel strength is 5 N / m or more and less than 15 N / m
• D Peel strength is less than 5 N / m The larger the value of, the better the adhesion to the base material.
• Lithium Metal Precipitation Test A laminated cell type lithium ion secondary battery is allowed to stand for 24 hours in an environment of a temperature of 25 ° C. after injecting an electrolytic solution, and then the cell is subjected to a constant current method of 0.1 C. A charge / discharge operation was performed in which the battery was charged to a voltage of 4.35 V and discharged to a cell voltage of 2.75 V. Next, in an environment of a temperature of -10 ° C, the cell voltage is charged to 4.35 V (CCCV charge 0.05C cut) by the constant current method of 1.5C, and the cell voltage is discharged to 2.75V at the same rate (CC discharge). ) The charging / discharging operation was repeated 5 times.
• the cell voltage was charged to 4.35 V by a constant current method of 0.2 C in an environment of a temperature of 25 ° C.
• the cell of the lithium ion secondary battery after the above operation was disassembled, the negative electrode was taken out, and the ratio of the portion where lithium metal was deposited (Li metal precipitation portion) to the entire surface of the negative electrode was calculated by image processing.
• the Li metal precipitation portion is determined from the color of the electrode surface. Specifically, in the negative electrode of the positive electrode facing surface portion, the gray to black portion is determined to be the Li metal precipitation portion, and the gold portion is determined to be the non-precipitation portion. bottom.
• Example 1 The binder composition, negative electrode, separator, and secondary battery of Example 1 were prepared as follows.
• 0.1 part of t-dodecyl mercaptan was added as a chain transfer agent, and the mixture was stirred at a temperature of 25 ° C. for 30 minutes to obtain a mixture for preparing a polymer in the shell part.
• the polymer solution of the shell part alone in the measurement of the weight average molecular weight of the shell part was polymerized at a temperature of 75 ° C. for 3 hours by adding 0.5 part of ammonium persulfate as a polymerization initiator to the system of the mixture without the core part. After that, a 5% aqueous sodium hydroxide solution was added to adjust the pH to 8.
• a 5% aqueous sodium hydroxide solution was added to the solution of the above reaction to adjust the pH from 2.5 to 8.0.
• the viscosity after neutralization was measured for a solution of this reaction product adjusted to a solid content concentration of 10%. Then, the unreacted monomer was removed by hot vacuum distillation. After that, it was cooled to obtain a binder composition.
• the obtained binder composition contains core-shell type particles, and the monomer composition of the core portion and the shell portion is as follows, which is substantially equal to the monomer unit composition of the polymer.
• the monomer composition of the core portion and the shell portion is as follows, which is substantially equal to the monomer unit composition of the polymer.
• the core monomer 33% of methyl methacrylate, 33% of n-butyl acrylate, 31% of 1,3-butadiene, and 3% of methacrylic acid.
• the 100% of the shell monomer 35% of ethyl acrylate, 34% of n-butyl acrylate, 30% of methacrylic acid, and 1% of ethylene glycol dimethacrylate.
• the ratio of the mass of the core portion to the mass of the shell portion is 70/30.
• the slurry composition for a secondary battery was applied on a copper foil (current collector) having a thickness of 18 ⁇ m with a comma coater so that the film thickness after drying was 105 ⁇ m and the coating amount was 10 mg / cm 2 .
• the copper foil coated with this composition is conveyed on the copper foil at a speed of 0.5 m / min in an oven at a temperature of 75 ° C. for 2 minutes and further in an oven at a temperature of 120 ° C. for 2 minutes.
• the composition was dried to obtain a negative electrode raw material. This negative electrode raw material was rolled by a roll press to obtain a negative electrode having a thickness of the negative electrode mixture layer of 80 ⁇ m.
• a planetary mixer LiCoO 2 95 parts having a spinel structure as a positive electrode active material, 3 parts of the solid content equivalent to PVDF (poly (vinylidene fluoride)) as a binder for the positive-electrode mixture layer, acetylene black 2 parts of a conductive material, Then, 20 parts of N-methylpyrrolidone as a solvent was added and mixed.
• the obtained composition was applied on an aluminum foil (current collector) having a thickness of 20 ⁇ m with a comma coater so that the film thickness after drying was about 100 ⁇ m.
• the aluminum foil coated with this composition is conveyed on the aluminum foil at a rate of 0.5 m / min in an oven at a temperature of 60 ° C. for 2 minutes and further in an oven at a temperature of 120 ° C. for 2 minutes.
• the composition was dried to obtain a positive electrode raw material.
• This positive electrode raw material was rolled by a roll press to obtain a positive electrode having a thickness of a positive electrode mixture layer of 70 ⁇ m.
• the obtained positive electrode was used for manufacturing a secondary battery.
• a single-layer polypropylene separator (width 65 mm, length 500 mm, thickness 25 ⁇ m; manufactured by a dry method; porosity 55%) was cut out into a square of 5 cm ⁇ 5 cm and used for manufacturing a secondary battery.
• an aluminum packaging material exterior was prepared.
• the positive electrode was cut out into a square of 4 cm ⁇ 4 cm and arranged so that the surface on the current collector side was in contact with the exterior of the aluminum packaging material.
• the square separator was placed on the surface of the positive electrode mixture layer of the positive electrode.
• the negative electrode was cut into a square having a size of 4.2 cm ⁇ 4.2 cm, and this was placed on the separator so that the surface on the negative electrode mixture layer side faced the separator.
• Examples 2 to 11, 26, Comparative Examples 1 to 8 The binder composition, the slurry composition for the secondary battery, the negative electrode, and the like in the same manner as in Example 1 except that the composition ratio and the type of the shell monomer were changed as shown in Table 1 when the shell was prepared. A secondary battery was manufactured. Then, various evaluations were performed in the same manner as in Example 1.
• the ethoxylated pentaerythritol tetraacrylate used in Example 9 and Comparative Example 8 has a product name of ATM35E manufactured by Shin Nihon Kagaku Kogyo Co., Ltd.
• Examples 12 and 13 The amount of t-dodecyl mercaptan (0.5 part), which is a chain transfer agent used in the preparation of the core part, was changed to 0.9 part in Example 10 and to 0.05 part in Example 11.
• a binder composition, a slurry composition for a secondary battery, a negative electrode, and a secondary battery were produced in the same manner as in Example 1 except for the above. Then, various evaluations were performed in the same manner as in Example 1.
• Examples 18 to 20> Except that the SBR binder was blended with the binder composition of Example 1 at the mass ratio as shown in Table 1 (the solid content equivalent of the binder in the binder composition is the same as that of Example 1). A slurry composition for a secondary battery, a negative electrode, and a secondary battery were produced in the same manner as in Example 1. Then, various evaluations were performed in the same manner as in Example 1.
• the SBR binder used was prepared as follows. 3.15 parts of styrene, 1.66 parts of 1,3-butadiene, 0.19 parts of itaconic acid, 0.2 part of sodium lauryl sulfate as an emulsifier, and 20 parts of ion-exchanged water in a 5 MPa pressure-resistant container A with a stirrer. A portion and 0.03 portion of potassium persulfate as a polymerization initiator were added, and the mixture was sufficiently stirred, then heated to a temperature of 60 ° C. to initiate polymerization, and reacted for 6 hours to obtain seed particles.
• the temperature is raised to 75 ° C., 58.85 parts of styrene as an aromatic-containing monomer, 33.34 parts of 1,3-butadiene as an aliphatic conjugated diene monomer, and other simple substances. 0.81 part of itaconic acid as a metric, 1 part of methyl methacrylate as a (meth) acrylic acid ester monomer which is another monomer, and 0.25 part of t-dodecyl mercaptan as a chain transfer agent.
• Example 21 Except that the SBS binder was blended with the binder composition of Example 1 at the mass ratio as shown in Table 1 (the solid content equivalent of the binder in the binder composition is the same as that of Example 1). A slurry for a secondary battery, a negative electrode, and a secondary battery were manufactured in the same manner as in Example 1. Then, various evaluations were performed in the same manner as in Example 1.
• the SBS binder used was prepared as follows. [Preparation of cyclohexane solution of block polymer] In a pressure resistant reactor, 233.3 kg of cyclohexane, 54.2 mmol of N, N, N', N'-tetramethylethylenediamine (hereinafter referred to as "TMEDA"), and 30.0 kg of styrene as an aromatic vinyl monomer. was added. Then, while stirring these at a temperature of 40 ° C., 1806.5 mmol of n-butyllithium as a polymerization initiator was added, and the mixture was polymerized for 1 hour while raising the temperature to 50 ° C. The polymerization conversion rate of styrene was 100%.
• 1,3-butadiene as an aliphatic conjugated diene monomer was continuously added to the pressure resistant reactor while controlling the temperature so as to maintain the temperature at 50 to 60 ° C. for 1 hour. After completing the addition of 1,3-butadiene, the polymerization reaction was continued for another hour. The polymerization conversion rate of 1,3-butadiene was 100%. Next, 722.6 mmol of dichlorodimethylsilane as a coupling agent was added to the pressure resistant reactor and the coupling reaction was carried out for 2 hours to form a styrene-butadiene coupling block copolymer.
• the obtained mixed solution was gradually added dropwise to warm water having a temperature of 85 to 95 ° C. to volatilize the solvent, and a precipitate was obtained. Then, this precipitate was crushed and dried with hot air at a temperature of 85 ° C. to recover the dried product containing the block polymer. Then, the recovered dried product was dissolved in cyclohexane to prepare a block polymer solution having a block polymer concentration of 5.0%.
• cyclohexane in the obtained emulsion was distilled off under reduced pressure using a rotary evaporator. Then, the distilled emulsion was centrifuged at 7000 rpm for 10 minutes with a centrifuge (manufactured by Hitachi Koki Co., Ltd., product name "Himac CR21N"), and then concentrated by taking out the upper layer portion. Finally, the upper layer portion was filtered through a 100-mesh wire mesh to obtain an aqueous dispersion (block polymer latex) containing a particulate block polymer.
• a centrifuge manufactured by Hitachi Koki Co., Ltd., product name "Himac CR21N
• Example 22 The same as in Example 1 except that the thickener used for preparing the slurry composition for the secondary battery was changed from sodium carboxymethyl cellulose to a lithium salt of an acrylic acid / acrylamide / hydroxyethyl acrylamide copolymer. , Binder composition, slurry composition for secondary battery, negative electrode and secondary battery were prepared. Then, various evaluations were performed in the same manner as in Example 1.
• the lithium salt of the acrylic acid / acrylamide / hydroxyethyl acrylamide copolymer used was prepared as follows.
• Example 23 The binder composition was the same as in Example 1 except that the SBR binder used in Example 18 was used as a solution of the core polymer and the composition ratio and type of the shell monomer were changed as shown in Table 1. A product, a slurry composition for a secondary battery, a negative electrode, and a secondary battery were prepared. Then, various evaluations were performed in the same manner as in Example 1.
• Example 24 The reaction product in the previous stage of [graft polymerization and cross-linking] of the SBS binder used in Example 21 was used as a solution of the core polymer, and the composition ratio and type of 100 parts of the shell monomer were as shown in Table 1.
• a binder composition, a slurry composition for a secondary battery, a negative electrode, and a secondary battery were produced in the same manner as in Example 1 except for the changes. Then, various evaluations were performed in the same manner as in Example 1.
• a slurry composition for a secondary battery, a negative electrode, and a secondary battery were prepared. Then, various evaluations were performed in the same manner as in Example 1.
• Example 27 Using the binder composition prepared in Example 1, a slurry composition for a porous membrane layer and a separator having a porous membrane layer were prepared as follows. A secondary battery was produced in the same manner as in Example 1 except that a separator provided with this porous film was used. Then, various evaluations were performed in the same manner as in Example 1.
• slurry composition for porous membrane layer [Preparation of slurry composition for porous membrane layer] Mix 100 parts of alumina (volume average particle size: 0.5 ⁇ m) as non-conductive particles, 1.0 part of ammonium polycarboxylic acid (manufactured by Toagosei, product name “Aron A-6114”) as a dispersant, and water. And obtained the mixture. The amount of water was adjusted so that the solid content concentration was 50%. The mixture was treated using a medialess disperser to disperse alumina to give a dispersion. To the obtained dispersion, 2.0 parts of sodium carboxymethyl cellulose (etherification degree: 1.0, aqueous solution viscosity at a solid content concentration of 1.0%: 500 mPa ⁇ s) was added and mixed.
• alumina volume average particle size: 0.5 ⁇ m
• ammonium polycarboxylic acid manufactured by Toagosei, product name “Aron A-6114”
• the added sodium salt of carboxymethyl cellulose was dissolved in the mixture.
• 5.0 parts (equivalent to solid content) of the binder composition of Example 1 and 0.2 parts of an aliphatic polyether type nonionic surfactant as a wetting agent were added to this mixed solution. Further, water was added so that the solid content concentration became 40% to obtain a slurry composition for a porous membrane layer.
• a single-layer polypropylene separator base material (width 250 mm, length 1000 m, thickness 12 ⁇ m) produced by a wet method was prepared. Then, the redispersed slurry composition for the porous membrane layer is applied onto both surfaces of the separator base material with a gravure coater (coating speed: 20 m / min) so that the thickness after drying is 2.5 ⁇ m. bottom. Next, the separator base material coated with the slurry composition for the porous membrane layer was dried in a drying oven at a temperature of 50 ° C. and wound up to prepare a separator having a porous membrane layer on both sides of the separator base material.
• This separator was cut out into a 5 cm ⁇ 5 cm square and used for manufacturing a secondary battery.
• the test piece for measuring the peel strength of the separator coating layer is provided with the porous film layer on one side in the same manner as above except that the slurry composition for the porous film layer is applied on one surface of the separator base material. It is a product of a separator.
• Example 28 Using the binder composition prepared in Example 1, a positive electrode slurry composition was prepared as follows.
• the negative electrode slurry composition was prepared in the same manner as the slurry composition for a secondary battery described in Example 1, but the SBR binder described in Examples 18 to 20 was used as the binder composition.
• a secondary battery was produced in the same manner as in Example 1 except that these positive electrode slurry compositions and negative electrode slurry compositions were used. Then, various evaluations were performed in the same manner as in Example 1.
• a powder was prepared by dry-mixing 100 parts of carbon-coated lithium iron phosphate and 10 parts of acetylene black as the conductive carbon in a closed container. To this powder, 100 parts of a 2% aqueous solution of sodium carboxymethyl cellulose (etherification degree: 1.0, aqueous solution viscosity at a solid content concentration of 1.0%: 500 mPa ⁇ s) as a water-soluble thickener was added to the planetary. A premix paste was prepared by mixing well with a mixer.
• the obtained premix paste was dispersed by a bead mill using zirconia beads having a diameter of 1 mm ⁇ , and then 3 parts (equivalent to solid content) of the binder composition of Example 1 was added and sufficiently mixed to be used for a positive electrode. A slurry composition was obtained.
• Example 11 The amount of the shell part charged is as shown in Table 1, except that the amount of t-dodecyl mercaptan as a chain transfer agent (0.1 part in Example 1) was changed to 3.5 parts when preparing the shell part.
• ⁇ Comparative Example 12> The amount of the shell part charged is as shown in Table 1, and the amount of t-dodecyl mercaptan as a chain transfer agent (0.1 part in Example 1) was changed to 0 part at the time of preparing the shell part, and at the time of polymerization of the shell part. Binder composition and slurry composition for secondary battery in the same manner as in Example 1 except that the amount of ammonium persulfate (0.5 part in Example 1), which is the polymerization initiator, was changed to 0.1 part. A product, a negative electrode, and a secondary battery were manufactured. Then, various evaluations were performed in the same manner as in Example 1. Then, various evaluations were performed in the same manner as in Example 1.
• a binder composition for a secondary battery is provided together with a slurry composition for a secondary battery, a functional layer for a secondary battery, a separator for a secondary battery, an electrode for a secondary battery, and a secondary battery.
• a slurry composition for a secondary battery a functional layer for a secondary battery
• a separator for a secondary battery an electrode for a secondary battery
• a secondary battery a secondary battery.

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