Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F285/00—Macromolecular compounds obtained by polymerising monomers on to preformed graft polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • 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
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • 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
  • 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
  • H01M4/13—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
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
• • 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
  • 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
• • 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 non-aqueous secondary battery electrodes, a slurry composition for non-aqueous secondary battery electrodes, an electrode for non-aqueous secondary batteries, and a non-aqueous secondary battery.
• Non-aqueous secondary batteries such as lithium-ion secondary batteries have the characteristics of being small, lightweight, and have a high energy density, as well as being able to be repeatedly charged and discharged. Yes, and used for a wide range of purposes. Therefore, in recent years, improvements in battery components such as electrodes have been studied with the aim of further improving the performance of non-aqueous secondary batteries.
• electrodes used in secondary batteries such as lithium ion secondary batteries usually include a current collector and an electrode composite material layer (positive electrode composite material layer or negative electrode composite material layer) formed on the current collector. It is equipped with This electrode mixture layer is formed by, for example, applying a slurry composition containing an electrode active material and a binder composition containing a binding material onto the current collector, and drying the applied slurry composition. It is formed.
• Patent Documents 1 to 4 monomers such as aromatic vinyl monomer units, aliphatic conjugated diene monomer units, carboxyl group-containing monomer units, etc. are used as binding materials contained in the binder composition. It is described that a particulate polymer containing units is used.
• the binder composition is required to have good tackiness.
• the adhesion between the electrode mixture layer and the current collector i.e., the peel strength of the electrode
• an object of the present invention is to provide a binder composition for a non-aqueous secondary battery electrode that can form an electrode for a non-aqueous secondary battery with excellent peel strength and has good tackiness.
• Another object of the present invention is to provide a slurry composition for a non-aqueous secondary battery electrode that can form an electrode for a non-aqueous secondary battery with excellent peel strength.
• an object of the present invention is to provide an electrode for a non-aqueous secondary battery that has excellent peel strength, and a non-aqueous secondary battery that includes the electrode for a non-aqueous secondary battery.
• the present inventors conducted extensive studies with the aim of solving the above problems.
• the present inventors made the particulate binder contain a polymer (A) containing a (meth)acrylic acid ester monomer unit. , and the particulate shape measured by dynamic light scattering at pH 8.0 with respect to the average particle diameter Da (pH 6.0) of the particulate binder measured by dynamic light scattering at pH 6.0. If the ratio of the average particle diameter Da (pH 8.0) of the binder (Da (pH 8.0) /Da (pH 6.0) ) is within a predetermined range, good tackiness of the binder composition can be maintained. However, the inventors have discovered that an electrode formed using the slurry composition can exhibit excellent peel strength, and have completed the present invention.
• a binder composition for a non-aqueous secondary battery electrode containing a particulate binder and water includes a polymer (A) containing a (meth)acrylic acid ester monomer unit, The particulate binder measured by dynamic light scattering at pH 8.0 relative to the average particle diameter Da (pH 6.0) of the particulate binder measured by dynamic light scattering at pH 6.0
• a binder composition for a non-aqueous secondary battery electrode in which the ratio of average particle diameter Da (pH 8.0) (Da (pH 8.0) /Da (pH 6.0) is more than 1.10.
• the particulate binder contains the polymer (A) containing (meth)acrylic acid ester monomer units, and the ratio of Da (pH 8.0) /Da (pH 6.0) is set to a predetermined value.
• a binder composition within this range has good tackiness and can form an electrode with excellent peel strength.
• the "monomeric unit" of a polymer means "a repeating unit derived from the monomer and contained in a polymer obtained using the monomer.”
• the average particle diameter Da of the particulate polymer can be specifically measured by the method described in the Examples of this specification.
• the particulate binder is the non-aqueous binder according to [1] above, wherein the surface layer contains a polymer (B) containing 80% by mass or more of acidic functional group-containing monomer units. It is preferred to provide a binder composition for secondary battery electrodes. Since the particulate binder contains the polymer (B) containing acidic functional group-containing monomer units in the surface layer, the binder composition has better tackiness and an electrode with better peel strength. can be formed.
• the present invention [3] Provide the binder composition for a non-aqueous secondary battery electrode according to [2] above, wherein the particulate binder has particles containing the polymer (A) inside the surface layer portion. is preferred. By having particles containing the polymer (A) inside the surface layer portion, the binder composition has better tackiness and can form an electrode with better peel strength.
• the particles are core-shell particles having a core part and a shell part,
• the core portion includes the polymer (A),
• the polymer (A) contains a (meth)acrylic acid ester monomer unit in a proportion of 80% by mass or more. is preferred. Since the particles are core-shell particles, the binder composition has better tackiness and can form an electrode with more excellent peel strength.
• the present invention [5] The binder composition for a non-aqueous secondary battery electrode according to [4] above, wherein the shell portion contains a polymer (C) containing aromatic vinyl monomer units in a proportion of 80% by mass or more. It is preferable to provide By including the polymer (C) in which the shell portion contains an aromatic vinyl monomer unit, the binder composition has better tackiness and can form an electrode with more excellent peel strength.
• the present invention [6] The binder composition for a non-aqueous secondary battery electrode according to [4] or [5] above, wherein the core portion accounts for 50% by mass or more and 98% by mass or less in the particulate binder. It is preferable to provide something.
• the binder composition has better tackiness and can form an electrode with better peel strength.
• the present invention [7] It is preferable to provide the binder composition for a non-aqueous secondary battery electrode according to any one of [1] to [6] above, which has a pH of 6.0 or more and 10.0 or less. When the pH is within the above range, the binder composition has better tackiness and can form an electrode with more excellent peel strength.
• the present invention [8] Provides a slurry composition for a non-aqueous secondary battery electrode, comprising an electrode active material and the binder composition for a non-aqueous secondary battery electrode according to any one of [1] to [7] above.
• a slurry composition has good tackiness and can form an electrode with excellent peel strength.
• an electrode for a non-aqueous secondary battery comprising an electrode mixture layer formed using the slurry composition for a non-aqueous secondary battery electrode according to [8] above.
• Such a slurry electrode has excellent peel strength.
• the present invention [10] Has a positive electrode, a negative electrode, a separator and an electrolyte, A non-aqueous secondary battery is provided, in which at least one of the positive electrode and the negative electrode is the non-aqueous secondary battery electrode according to [9] above.
• Such non-aqueous secondary batteries have an improved lifespan by using electrodes with excellent peel strength, and also have excellent performance in terms of internal resistance and cycle characteristics.
• the present invention it is possible to form a non-aqueous secondary battery electrode with excellent peel strength, and to provide a binder composition for a non-aqueous secondary battery electrode that has good tackiness. Further, according to the present invention, it is possible to provide a slurry composition for a non-aqueous secondary battery electrode that can form an electrode for a non-aqueous secondary battery with excellent peel strength. Further, according to the present invention, it is possible to provide an electrode for a non-aqueous secondary battery that has excellent peel strength, and a non-aqueous secondary battery that includes the electrode for a non-aqueous secondary battery.
• the binder composition for non-aqueous secondary battery electrodes of the present invention (hereinafter sometimes simply referred to as "binder composition”) is the slurry composition for non-aqueous secondary battery electrodes of the present invention (hereinafter, sometimes simply referred to as "binder composition”). (sometimes simply referred to as a "slurry composition”).
• the slurry composition for non-aqueous secondary battery electrodes prepared using the binder composition for non-aqueous secondary battery electrodes of the present invention can be used when manufacturing electrodes for non-aqueous secondary batteries such as lithium ion secondary batteries. It can be used for.
• the non-aqueous secondary battery of the present invention includes an electrode for a non-aqueous secondary battery of the present invention (hereinafter simply referred to as "electrode") formed using the slurry composition for a non-aqueous secondary battery electrode of the present invention. ).
• the binder composition for non-aqueous secondary battery electrodes, the slurry composition for non-aqueous secondary battery electrodes, and the electrode for non-aqueous secondary batteries of the present invention are preferably for negative electrodes.
• the secondary battery preferably uses the non-aqueous secondary battery electrode of the present invention as a negative electrode.
• the binder composition for a nonaqueous secondary battery electrode of the present invention includes a particulate binder and water, and the particulate binder is a polymer containing a (meth)acrylic acid ester monomer unit.
• A and measured by dynamic light scattering at pH 8.0 relative to the average particle diameter Da (pH 6.0) of the particulate binder measured by dynamic light scattering at pH 6.0.
• the ratio of the average particle diameter Da (pH 8.0) of the particulate binder (Da (pH 8.0) /Da (pH 6.0) ) is within a predetermined range.
• the binder composition for non-aqueous secondary battery electrodes of the present invention contains the above-mentioned predetermined particulate binder, and therefore has good tackiness, and can be formed using a slurry composition containing the binder composition. This allows the electrode to exhibit excellent peel strength.
• the performance of a secondary battery can be improved, for example, battery characteristics such as cycle characteristics can be improved.
• the internal resistance of the secondary battery can be reduced.
• an electrode can be manufactured by coating (coating and drying) a slurry composition prepared using the binder composition at high speed. Even if there is, the formed electrode can exhibit excellent peel strength.
• the particulate binder is used as a component for retaining components such as electrode active materials so that they do not separate from the electrode composite layer in the electrode composite layer formed using a slurry composition containing a binder composition.
• the particulate binder is a water-insoluble particle made of a predetermined polymer.
• particles such as particulate binder are "water-insoluble" when the insoluble matter is 90% by mass or more when 0.5g of particles is dissolved in 100g of water at a temperature of 25°C. It means that.
• the particulate binder may have any structure as long as it contains the polymer (A) and Da (pH 8.0) /Da (pH 6.0) is within a predetermined range .
• the polymer (B) may be included in the surface layer portion.
• the polymer (B) preferably contains acidic functional group-containing monomer units in a proportion of 80% by mass or more.
• examples of the structure containing the polymer (B) in the surface layer include a structure having particles containing the polymer (A) inside the surface layer made of the polymer (B).
• the particles containing the polymer (A) located inside the surface layer portion are not particularly limited, but include (i) particles made of the polymer (A), (ii) a core portion and a shell portion. and core-shell particles having one of the core portion and the shell portion formed using polymer A, and the like.
• the core part is a core-shell particle containing the polymer (A)
• the core part is a core-shell particle containing the polymer (A)
• the core part is a core-shell particle containing the polymer (A)
• the core-shell particles include a polymer (C) in which the shell portion contains aromatic vinyl monomer units in a proportion of 80% by mass or more.
• the proportion of the core portion in the particulate binder is preferably 50% by mass or more, more preferably 55% by mass or more, It is more preferably 60% by mass or more, preferably 98% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and even more preferably 80% by mass or less. is particularly preferred.
• the proportion of the core portion in the particulate binder is within the above range, the peel strength of the electrode and the tackiness of the composition can be improved.
• the proportion of the shell portion in the particulate binder is preferably 1% by mass or more, more preferably 5% by mass or more, It is more preferably 10% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.
• the proportion of the core portion in the particulate binder is within the above range, the peel strength of the electrode and the tackiness of the composition can be improved.
• the proportion of the surface layer in the particulate binder is preferably 0.5% by mass or more, and 1% by mass. It is more preferably at least 2% by mass, even more preferably at least 30% by mass, more preferably at most 25% by mass, even more preferably at most 20% by mass. .
• the proportion of the core portion in the particulate binder is within the above range, the peel strength of the electrode and the tackiness of the composition can be improved.
• the polymer (A) contains (meth)acrylic acid ester monomer units. Further, the polymer (A) optionally further contains an acidic functional group-containing monomer unit, an unsaturated carboxylic acid amide monomer unit, an unsaturated carboxylic acid epoxy monomer unit, and a crosslinkable monomer unit. You may do so. Further, the polymer (A) may optionally contain a (meth)acrylic acid ester monomer unit, an acidic functional group-containing monomer unit, an unsaturated carboxylic acid amide monomer unit, an unsaturated carboxylic acid epoxy monomer unit, etc. It may further contain monomer units other than the above unit (hereinafter sometimes referred to as "other monomer units"). Specific examples of the monomer units contained in the polymer (A) will be described later.
• the polymer (A) preferably contains (meth)acrylic acid ester monomer units when the amount of all repeating units (monomer units) in the polymer (A) is 100% by mass. It is contained in a proportion of 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more, preferably 100% by mass or less, more preferably 99% by mass or less, still more preferably 98% by mass or less.
• the polymer (A) has a (meth)acrylic acid ester monomer content when the amount of all repeating units (monomer units) in all the polymers constituting the particulate binder is 100% by mass.
• the proportion of body units is preferably 50% by mass or more, more preferably 55% by mass or more, still more preferably 70% by mass or more, preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 77% by mass or less.
• the polymer (A) preferably contains acidic functional group-containing monomer units at 0.1% by mass when the amount of all repeating units (monomer units) in the polymer (A) is 100% by mass.
• the content is more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, preferably 8% by mass or less, more preferably 6% by mass or less, still more preferably 4% by mass or less.
• the polymer (A) is composed of acidic functional group-containing monomer units, when the amount of all repeating units (monomer units) in all the polymers constituting the particulate binder is 100% by mass.
• the proportion of acidic functional group-containing monomer units in the monomer units in the polymer (A) is within the above range, the cycle characteristics of the secondary battery can be improved.
• the polymer (A) preferably contains 0.1 mass% of unsaturated carboxylic acid amide monomer units when the amount of all repeating units (monomer units) in the polymer (A) is 100% by mass. % or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, preferably 12% by mass or less, more preferably 6% by mass or less, still more preferably 3% by mass or less.
• the polymer (A) is an unsaturated carboxylic acid amide monomer when the amount of all repeating units (monomer units) in all the polymers constituting the particulate binder is 100% by mass.
• the unit preferably contains 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass. Contain in the following proportions.
• the proportion of unsaturated carboxylic acid amide monomer units in the monomer units in the polymer (A) is within the above range, the cycle characteristics of the secondary battery can be improved.
• the polymer (A) preferably contains 0.1% by mass or more of crosslinkable monomer units, when the amount of all repeating units (monomer units) in the polymer (A) is 100% by mass.
• the content is more preferably 0.5% by mass or more, still more preferably 0.8% by mass or more, preferably 12% by mass or less, more preferably 6% by mass or less, still more preferably 3% by mass or less.
• the polymer (A) preferably contains crosslinkable monomer units when the amount of all repeating units (monomer units) in all the polymers constituting the particulate binder is 100% by mass.
• the cycle characteristics of the secondary battery can be improved.
• the polymer (A) When the amount of all repeating units (monomeric units) in the polymer (A) is 100% by mass, the polymer (A) preferably contains 0.1% by mass or more of other monomeric units, The content is more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, preferably 12% by mass or less, more preferably 6% by mass or less, still more preferably 3.0% by mass or less. In addition, the polymer (A) preferably contains other monomer units when the amount of all repeating units (monomer units) in all the polymers constituting the particulate binder is 100% by mass.
• the polymer (B) contains acidic functional group-containing monomer units. Further, the polymer (B) may optionally further contain monomer units other than the acidic functional group-containing monomer units. Specific examples of the "acidic functional group-containing monomer unit" will be described later.
• the acidic functional group-containing monomer unit contained in the polymer (B) is the acidic functional group contained in the polymer (A). It may be the same as or different from the monomer unit contained.
• the polymer (B) preferably contains 80% by mass of acidic functional group-containing monomer units when the amount of all repeating units (monomer units) in the polymer (B) is 100% by mass. % or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, particularly preferably 100% by mass.
• the polymer (B) is an acidic functional group-containing monomer unit when the amount of all repeating units (monomer units) in all the polymers constituting the particulate binder is 100% by mass.
• the proportion of Contains in When the proportion of acidic functional group-containing monomer units in the monomer units in the polymer (B) is within the above range, the peel strength of the electrode can be improved.
• the polymer (C) contains aromatic vinyl monomer units. Further, the polymer (C) may optionally further contain monomer units other than aromatic vinyl monomer units. Specific examples of the "aromatic vinyl monomer unit" will be described later.
• the aromatic vinyl monomer unit contained in the polymer (C) is the aromatic vinyl monomer unit contained in the polymer (A). It may be the same as the body unit or may be different.
• the polymer (C) preferably contains 80% by mass of aromatic vinyl monomer units when the amount of all repeating units (monomer units) in the polymer (C) is 100% by mass.
• the content is more preferably 90% by mass or more, still more preferably 95% by mass or more, particularly preferably 100% by mass.
• the polymer (C) contains aromatic vinyl monomer units when the amount of all repeating units (monomer units) in all the polymers constituting the particulate binder is 100% by mass.
• the proportion of aromatic vinyl monomer units in the monomer units in the polymer (C) is within the above range, the tackiness of the composition can be improved.
• Monomer units contained in polymer (A), polymer (B), and polymer (C) are as follows.
• Examples of the (meth)acrylic ester monomer that can form the (meth)acrylic ester monomer unit in the particulate binder include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, and n-propyl acrylate.
• butyl acrylate such as butyl acrylate and t-butyl acrylate
• octyl acrylate such as pentyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate, etc.
• Acrylic acid alkyl esters and butyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate and t-butyl methacrylate, octyl esters such as pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate
• methacrylic acid alkyl esters such as methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, and stearyl methacrylate. Note that these may be used alone or in combination of two or more in any ratio.
• acidic functional group-containing monomer unit examples of the acidic functional group-containing monomer that can form the acidic functional group-containing monomer unit in the particulate binder include phosphoric acid group-containing monomer units, sulfonic acid group-containing monomer units, and , a carboxylic acid group-containing monomer unit. Among these, carboxylic acid group-containing monomer units are preferred.
• the phosphoric acid group-containing monomer is a monomer having a phosphoric acid group and a polymerizable group that can be copolymerized with other monomers.
• organic groups as R 1a and R 2a include aliphatic groups such as octyl groups, aromatic groups such as phenyl groups, and the like.
• Examples of the phosphoric acid group-containing monomer include compounds containing a phosphoric acid group and an allyloxy group. Examples of compounds containing a phosphoric acid group and an allyloxy group include 3-allyloxy-2-hydroxypropane phosphoric acid.
• the sulfonic acid group-containing monomer is a monomer having a sulfonic acid group and a polymerizable group that can be copolymerized with other monomers.
• sulfonic acid group-containing monomers include sulfonic acid group-containing monomers or salts thereof that have no functional groups other than sulfonic acid groups and polymerizable groups, and sulfonic acid group-containing monomers that have no functional groups other than sulfonic acid groups and polymerizable groups.
• Examples include monomers containing an amide group or salts thereof, and monomers containing a hydroxyl group or salts thereof in addition to a sulfonic acid group and a polymerizable group.
• Examples of sulfonic acid group-containing monomers having no functional group other than a sulfonic acid group and a polymerizable group include monomers obtained by sulfonating one of the conjugated double bonds of diene compounds such as isoprene and butadiene. , vinylsulfonic acid, styrenesulfonic acid, allylsulfonic acid, and the like. Further, examples of the salt include lithium salt, sodium salt, potassium salt, and the like. Examples of monomers containing an amide group in addition to a sulfonic acid group and a polymerizable group include 2-acrylamido-2-methylpropanesulfonic acid (AMPS).
• AMPS 2-acrylamido-2-methylpropanesulfonic acid
• examples of the salt include lithium salt, sodium salt, potassium salt, and the like.
• examples of the monomer containing a hydroxyl group in addition to a sulfonic acid group and a polymerizable group include 3-allyloxy-2-hydroxypropanesulfonic acid (HAPS).
• examples of the salt include lithium salt, sodium salt, potassium salt, and the like. Among these, styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and salts thereof are preferred.
• the carboxylic acid group-containing monomer can be a monomer having a carboxylic acid group and a polymerizable group.
• Specific examples of the carboxylic acid group-containing monomer include ethylenically unsaturated carboxylic acid monomers.
• ethylenically unsaturated carboxylic acid monomer examples include ethylenically unsaturated monocarboxylic acids and their derivatives, ethylenically unsaturated dicarboxylic acids and their acid anhydrides, and their derivatives.
• ethylenically unsaturated monocarboxylic acids include acrylic acid, methacrylic acid and crotonic acid.
• Examples of derivatives of ethylenically unsaturated monocarboxylic acids include 2-ethyl acrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid and Examples include ⁇ -diaminoacrylic acid.
• Examples of ethylenically unsaturated dicarboxylic acids include maleic acid, fumaric acid and itaconic acid.
• Examples of acid anhydrides of ethylenically unsaturated dicarboxylic acids include maleic anhydride, acrylic anhydride, methylmaleic anhydride, and dimethylmaleic anhydride.
• Examples of derivatives of ethylenically unsaturated dicarboxylic acids include methylallyl maleate such as methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, and fluoromaleic acid; as well as diphenyl maleate and nonyl maleate. , decyl maleate, dodecyl maleate, octadecyl maleate, and fluoroalkyl maleate.
• ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid are preferred.
• the water-insoluble particulate polymer may contain only one type of acidic group-containing monomer unit, or may contain a combination of two or more types.
• Unsaturated carboxylic acid amide monomer unit examples of the unsaturated carboxylic acid amide monomer that can form the unsaturated carboxylic acid amide monomer unit in the particulate binder include acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, and N-methylolmethacrylamide. , N-dimethylacrylamide, hydroxyethylacrylamide, and the like. Note that these may be used alone or in combination of two or more in any ratio.
• the crosslinkable monomer that can form the crosslinkable monomer unit in the particulate binder is not particularly limited, and includes monomers that can form a crosslinked structure through polymerization.
• Examples of crosslinkable monomers include monomers that typically have thermal crosslinkability. More specifically, a crosslinkable monomer having a thermally crosslinkable crosslinkable group and one olefinic double bond per molecule; a crosslinkable monomer having two or more olefinic double bonds per molecule One example is the body.
• thermally crosslinkable groups examples include epoxy groups, N-methylolamide groups, oxetanyl groups, oxazoline groups, and combinations thereof.
• epoxy groups are more preferred since crosslinking and crosslinking density can be easily controlled.
• crosslinkable monomers having an epoxy group as a thermally crosslinkable crosslinkable group and an olefinic double bond include vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o- Unsaturated glycidyl ethers such as allyl phenyl glycidyl ether; butadiene monoepoxide, chloroprene monoepoxide, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9- monoepoxides of dienes or polyenes such as cyclododecadiene; alkenyl epoxides such as 3,4-epoxy-1-butene, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene; and glycidyl acrylates, Glycidyl methacryl
• examples include (meth)acrylamides.
• crosslinkable monomers having an oxetanyl group as a thermally crosslinkable crosslinkable group and an olefinic double bond include 3-((meth)acryloyloxymethyl)oxetane, 3-( (meth)acryloyloxymethyl)-2-trifluoromethyloxetane, 3-((meth)acryloyloxymethyl)-2-phenyloxetane, 2-((meth)acryloyloxymethyl)oxetane and 2-((meth)acryloyl (oxymethyl)-4-trifluoromethyloxetane.
• crosslinkable monomers having an oxazoline group as a thermally crosslinkable crosslinkable group and an olefinic double bond examples include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl -2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2- Mention may be made of oxazoline and 2-isopropenyl-5-ethyl-2-oxazoline.
• crosslinkable monomers having two or more olefinic double bonds per molecule examples include allyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and triethylene glycol.
• "(meth)acrylate” means acrylate and/or methacrylate.
• One type of crosslinkable monomer may be used alone, or a plurality of types may be used in combination.
• examples include styrene and aromatic monovinyl compounds such as vinylnaphthalene. Among them, styrene is preferred. These can be used alone or in combination of two or more, but it is preferable to use one type alone.
• Other monomer units that the particulate polymer may further include are not particularly limited, but include, for example, hydrophilic monomer units that do not contain acidic groups.
• the particulate polymer further contains a hydrophilic monomer unit that does not contain an acidic group as another monomer unit. If the particulate polymer further contains a hydrophilic monomer unit that does not contain an acidic group, the tack strength of the binder composition can be reduced.
• Hydrophilic monomers that do not contain acidic groups that can form hydrophilic monomer units that do not contain acidic groups in particulate polymers include, for example, hydroxyl group-containing monomers; nitrile groups such as (meth)acrylonitrile; Containing monomers; polyalkylene oxide structure-containing monomers; and the like. These may be used alone or in combination of two or more in any ratio.
• (meth)acrylic means acrylic and/or methacryl
• (meth)acrylonitrile” means acrylonitrile and/or methacrylonitrile.
• examples of the hydroxyl group-containing monomer include ethylenically unsaturated alcohols such as (meth)allyl alcohol, 3-buten-1-ol, and 5-hexen-1-ol; 2-hydroxyethyl vinyl ether, 2- Vinyl ethers such as hydroxypropyl vinyl ether; (meth)allyl-2-hydroxyethyl ether, (meth)allyl-2-hydroxypropyl ether, (meth)allyl-3-hydroxypropyl ether, (meth)allyl-2-hydroxybutyl ether , (meth)allyl-3-hydroxybutyl ether, (meth)allyl-4-hydroxybutyl ether, (meth)allyl-6-hydroxyhexyl ether, and other alkylene glycol mono(meth)allyl ethers; diethylene glycol mono(meth)allyl Polyoxyalkylene glycol mono(meth)allyl ethers such as ether, dipropylene glycol mono(meth)allyl ether;
• a polyethylene oxide structure-containing monomer can be used.
• the number of carbon atoms in the alkyl group constituting R 2 is preferably 3 or less, more preferably 2 or less, and even more preferably 1.
• n is preferably 7 or more, preferably 9 or more, and preferably 25 or less, more preferably 15 or less.
• Examples include monomers containing a polyethylene oxide structure, such as product names "AM-90G”, “AM-130G”, “M-90G”, and “M-230G” (all manufactured by Shin-Nakamura Chemical Co., Ltd.). These can be used alone or in combination of two or more in any ratio.
• hydrophilic monomer that does not contain an acidic group it is preferable to use acrylonitrile from the viewpoint of further reducing the tack strength of the binder composition while suppressing foaming of the slurry composition containing the binder composition. .
• the solubility in water of the hydrophilic monomer that does not contain an acidic group is preferably 10,000 mg/L or more, more preferably 12,000 mg/L or more, and 14,000 mg/L or more. is more preferable, preferably 2,000,000 mg/L or less, and more preferably 1,900,000 mg/L or less. If the solubility of the hydrophilic monomer that does not contain an acidic group in water is at least the above lower limit, the tack strength of the binder composition can be further reduced. On the other hand, if the solubility of the hydrophilic monomer that does not contain an acidic group in water is below the above upper limit, foaming of the slurry composition containing the binder composition can be suppressed.
• “solubility in water” refers to solubility in water at 25°C.
• the content of acid ester monomer units is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and 90% by mass or less.
• the content is preferably 80% by mass or less, more preferably 77% by mass or less.
• Acidic functional group content in all polymers constituting particulate binder when the amount of all repeating units (monomer units) in all polymers constituting particulate binder is 100% by mass
• the content ratio of monomer units is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and 20% by mass or less.
• the content is preferably 15% by mass or less, more preferably 8% by mass or less, and even more preferably 8% by mass or less.
• the content of the amide monomer unit is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and 10% by mass or less.
• the content is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 3% by mass or less.
• the amount of all repeating units (monomer units) in all the polymers that make up the particulate binder is 100% by mass
• the amount of crosslinkable monomers in all the polymers that make up the particulate binder The content of body units is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and 10% by mass or less.
• the content is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 2% by mass or less.
• the amount of all repeating units (monomer units) in all the polymers that make up the particulate binder is 100% by mass
• the amount of aromatic vinyl units in all the polymers that make up the particulate binder is 100% by mass.
• the content of the mer unit is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and preferably 30% by mass or less, It is more preferably 25% by mass or less, and even more preferably 20% by mass or less.
• the amount of all repeating units (monomer units) in all the polymers that make up the particulate binder is 100% by mass
• the amount of other monomers in all the polymers that make up the particulate binder The content of body units is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and 10% by mass or less.
• the content is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 2% by mass or less.
• the average particle diameter Da of the particulate binder measured by a dynamic light scattering method can vary depending on the pH.
• the average particle diameter Da (pH 6.0) of the particulate binder measured by dynamic light scattering at pH 6.0 is preferably 100 nm or more, more preferably 150 nm or more, and 200 nm or more. It is more preferably 3 ⁇ m or less, more preferably 1 ⁇ m or less, and even more preferably 600 nm or less.
• the average particle diameter Da (pH 8.0) of the particulate binder measured by dynamic light scattering at pH 8.0 is preferably 100 nm or more, more preferably 150 nm or more, and 200 nm or more. It is more preferably 3 ⁇ m or less, more preferably 1 ⁇ m or less, and even more preferably 600 nm or less.
• the value of the average particle diameter Da of the particulate binder measured by a dynamic light scattering method depends on, for example, the type and amount of the monomer used to form the particulate binder, the polymerization method and conditions, and It can be adjusted depending on the structure of the particulate binder.
• the average particle diameter Da of the particulate binder at each pH can be measured by the following method.
• the pH of an aqueous dispersion (binder composition) containing a particulate binder is adjusted.
• the pH can be adjusted, for example, by adding an acid (eg, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, etc.) or a base (eg, sodium hydroxide, potassium hydroxide, aqueous ammonia, etc.).
• an acid eg, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, citric acid, etc.
• a base eg, sodium hydroxide, potassium hydroxide, aqueous ammonia, etc.
• the particle size distribution of the aqueous dispersion (binder composition) after pH adjustment was measured using a particle size distribution measuring device (manufactured by Otsuka Electronics Co., Ltd., model "nanoSAQLA”) that uses dynamic light scattering as the measurement principle.
• the particle size (D50) at which the cumulative frequency of light scattering intensity calculated from the small diameter side was 50% was defined as the average particle size Da.
• the measurement conditions for the dynamic light scattering method are as follows. Dispersion medium: Ion exchange water Measurement temperature: 25 ⁇ 1°C Measured concentration (solid content concentration): 0.5% by mass Scattering angle: 168.8° Light source laser wavelength: 660nm
• the ratio of the average particle diameter Da (pH 8.0) (Da (pH 8.0) /Da (pH 6.0) ) needs to be more than 1.10, and preferably 1.20 or more. , more preferably 1.50 or more, preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less.
• the peel strength of the electrode formed using the binder composition can be sufficiently improved.
• the reason why the peel strength of the electrode formed using the binder composition can be sufficiently improved when the ratio of Da (pH 8.0) /Da (pH 6.0) is equal to or higher than the above lower limit is obvious.
• the particulate binder migrates to the surface side of the electrode mixture layer (i.e., the side opposite to the current collector side). It is considered that the peel strength of the electrode can be sufficiently improved by having the particulate binder well dispersed and present in the electrode composite material layer.
• the ratio of Da (pH 8.0) /Da (pH 6.0) is below the above upper limit, the tackiness of the binder composition is improved by suppressing the viscosity of the binder composition from increasing excessively. Can be maintained well.
• the volume average particle diameter Db of the particulate binder measured by a laser diffraction scattering method is preferably 100 nm or more, more preferably 150 nm or more, even more preferably 200 nm or more, and 3 ⁇ m or less. It is preferably 1 ⁇ m or less, more preferably 600 nm or less, and even more preferably 600 nm or less.
• the volume average particle diameter Db of the particulate binder measured by a laser diffraction scattering method is within the above predetermined range, the peel strength of the electrode formed using the binder composition can be sufficiently improved. .
• the injectability of the electrolyte of a secondary battery equipped with an electrode formed using a binder composition is improved.
• the ratio (Da (pH 6.0) / Db) is preferably 0.8 or more, more preferably 0.85 or more, even more preferably 0.9 or more, and 1.5 or less. It is preferable that it is, it is more preferable that it is 1.2 or less, and it is still more preferable that it is 1.2 or less.
• the average particle diameter Da of the particulate binder measured by the dynamic light scattering method at pH 8.0 (pH 8.0) with respect to the volume average particle diameter Db of the particulate binder measured by the laser diffraction scattering method is preferably 1.1 or more, more preferably 1.2 or more, even more preferably 1.5 or more, and 3.0 or less. It is preferable that it is, it is more preferable that it is 2.5 or less, and it is still more preferable that it is 2.0 or less.
• the binder composition when using a binder composition containing a particulate binder in which the ratio of Da (pH 6.0) /Db and the ratio of Da (pH 8.0) /Db are equal to or higher than the above lower limit, the binder composition is When forming an electrode mixture layer by applying a slurry composition containing the composition onto a current collector and drying it, the particulate binder is placed on the surface side of the electrode mixture layer (i.e., on the current collector side).
• the peel strength of the electrode can be sufficiently improved by the presence of a well-dispersed particulate binder in the electrode composite material layer. Conceivable.
• the pH of the binder composition for non-aqueous secondary battery electrodes (the pH of the aqueous phase) is preferably 6 or higher, more preferably 7 or higher, preferably 10 or lower, and 9 or lower. is more preferable, and even more preferably 8 or less. If the pH of the binder composition is at least the above lower limit, the peel strength of the electrode formed using the binder composition can be further improved. On the other hand, if the pH of the binder composition is below the above upper limit, the tackiness of the binder composition can be maintained well by suppressing the viscosity of the binder composition from increasing excessively.
• the pH may be adjusted by adding an alkaline species to the aqueous phase.
• alkali species include lithium hydroxide, sodium hydroxide, potassium hydroxide, and aqueous ammonia, and aqueous ammonia is preferred because it is less likely to generate aggregates due to the shock of addition during alkali neutralization.
• the binder composition for a nonaqueous secondary battery electrode may contain an acidic water-soluble polymer, an antiaging agent, a preservative, an antifoaming agent, etc. in the aqueous phase.
• the binder composition of the present invention may contain a binder (other binder) other than the particulate binder containing the above-mentioned polymer (A).
• binders for example, water-insoluble polymers and particulate polymers can be used.
• the acidic water-soluble polymer that can be contained in the aqueous phase of the binder composition for non-aqueous secondary battery electrodes is, for example, a monomer that becomes a raw material for the particulate binder when the particulate binder is produced by polymerization. Polymerized as a by-product.
• Such an acidic water-soluble polymer is, for example, a polymer that contains a carboxyl group-containing monomer unit and may optionally further contain an aromatic vinyl monomer unit or an aliphatic conjugated diene monomer unit. be.
• Monomers that can form each monomer unit such as a carboxyl group-containing monomer unit, an aromatic vinyl monomer unit, and an aliphatic conjugated diene monomer unit that can be contained in the acidic water-soluble polymer include: The monomers mentioned above in the section of "particulate binder" can be used.
• the weight average molecular weight of such an acidic water-soluble polymer is preferably 500 or more, more preferably 700 or more, even more preferably 1,000 or more, and preferably 20,000 or less. It is preferably 15,000 or less, even more preferably 8,000 or less, even more preferably 3,500 or less, and even more preferably 2,000 or less. If the weight average molecular weight of the acidic water-soluble polymer is at least the above lower limit, the peel strength of the electrode formed using the binder composition can be further improved. On the other hand, if the weight average molecular weight of the acidic water-soluble polymer is below the above upper limit, the tackiness of the binder composition can be maintained well by suppressing the viscosity of the binder composition from increasing excessively. .
• the acidic water-soluble polymer may be in the form of a salt (salt of an acidic water-soluble polymer). That is, in the present invention, the "acidic water-soluble polymer” also includes salts of the acidic water-soluble polymer.
• water-soluble as used herein means that when 0.5g of the polymer is dissolved in 100g of water at a temperature of 25°C, the insoluble matter is less than 1.0% by mass. say.
• antioxidants e.g., 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di- tert-butylphenol, 2,6-di-tert-butyl-p-cresol, stearyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis [3-(3,5 -di-tert-butyl-4-hydroxyphenyl)propionate], 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene), oligomeric phenolic antioxidant agents (e.g., 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di- tert-butylphenol, 2,6-di-tert-
• phosphite antioxidants e.g. 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3 ,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 2,2-methylenebis(4 , 6-di-tert-butylphenyl) 2-ethylhexyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite), sulfur-based antioxidants (e.g. didodecyl 3,3'-thiodipro pionate), etc.
• phosphite antioxidants e.g. 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9
• the amount of the anti-aging agent added is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, and 10 parts by mass or less with respect to 100 parts by mass of the particulate binder. is preferable, and more preferably 5 parts by mass or less.
• preservative examples include known preservatives such as isothiazoline compounds and 2-bromo-2-nitro-1,3-propanediol.
• the isothiazoline compound is not particularly limited, and examples thereof include those described in JP-A No. 2013-211246, JP-A No. 2005-097474, and JP-A No. 2013-206624.
• one kind of preservative may be used alone, or two or more kinds may be used in combination.
• the preservatives include 1,2-benzisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-bromo-2 -Nitro-1,3-propanediol is preferred, and 1,2-benzisothiazolin-3-one is more preferred.
• the amount of preservative contained in the binder composition is preferably 0.01 parts by mass or more, preferably 0.5 parts by mass or less, and 0.01 parts by mass or less, preferably 0.5 parts by mass or less, based on 100 parts by mass of the particulate binder. It is more preferably 4 parts by mass or less, and even more preferably 0.3 parts by mass or less. If the preservative content is 0.01 parts by mass or more per 100 parts by mass of the particulate binder, the formation of aggregates in the binder composition after long-term storage can be further suppressed, and 0.5 parts by mass If it is below, the peel strength of the electrode can be ensured to be sufficiently high.
• the binder composition for non-aqueous secondary battery electrodes of the present invention contains monomers ((meth)acrylic acid ester monomer units, acidic functional group-containing monomers, It can be prepared by polymerizing in an emulsion a monomer unit, an unsaturated carboxylic acid amide monomer unit, a crosslinkable monomer unit, an aromatic vinyl monomer unit, and other monomer units.
• Examples of such a preparation method include a batch emulsion polymerization method, an emulsion (Em) prop method, and a seed polymerization method.
• the batch emulsion polymerization method may be performed, for example, by the following procedure.
• Monomers that are the source of the monomer units contained in the particulate binder ((meth)acrylic ester monomer units, acidic functional group-containing monomer units, unsaturated carboxylic amide monomer units, crosslinkable monomer units, aromatic vinyl monomer units, and other monomer units) are mixed with water, an emulsifier, and a polymerization initiator.
• the mixture (emulsion) is heated to perform a polymerization reaction. When a predetermined polymerization conversion rate is reached, the reaction is stopped by cooling to obtain a mixture containing a particulate binder. Remove unreacted monomer from the mixture.
• the pH of the mixture is adjusted to be within the preferred pH range of the aqueous phase described above, and optionally, the additives described above (e.g., anti-aging agents) are added to prepare the aqueous dispersion for use in non-aqueous secondary batteries. Obtained as a binder composition for electrodes. Heating during the polymerization reaction is, for example, 40°C or higher, 45°C or higher, 50°C or higher, 55°C or higher, or 60°C or higher, 90°C or lower, 85°C or lower, 80°C or lower, 75°C or lower, or 70°C or higher It may be carried out at temperatures below °C. Removal of unreacted monomers from the mixture may be performed, for example, by distillation under reduced pressure under heat or by blowing steam.
• the additives described above e.g., anti-aging agents
• the Em prop method may be performed, for example, by the following procedure.
• Monomers for forming the core ((meth)acrylic acid ester monomer unit, and optionally acidic functional group-containing monomer unit, unsaturated carboxylic acid amide monomer unit, unsaturated carboxylic acid epoxy monomer unit) monomer units contained in the polymer (A), such as monomer units, crosslinkable monomer units, and other monomer units), with water, an emulsifier, a polymerization initiator, and optionally a chain transfer agent.
• the mixture (emulsion) is heated and a polymerization reaction is performed until a predetermined polymerization conversion rate is reached, thereby obtaining a mixture containing a seed particle polymer as a core portion.
• a monomer for forming a shell portion an aromatic vinyl monomer, and optionally a monomer unit contained in the polymer (C) such as a monomer unit other than the aromatic vinyl monomer unit
• a monomer for forming a shell portion an aromatic vinyl monomer, and optionally a monomer unit contained in the polymer (C) such as a monomer unit other than the aromatic vinyl monomer unit
• Polymerization is continued by continuous addition of polymers (units) and, optionally, emulsifiers and water.
• a polymer (B) containing monomers for forming the surface layer (acidic functional group-containing monomer units, and optionally monomer units other than the acidic functional group-containing monomer units) is added to the mixture.
• Polymerization is continued by successive additions of monomer units), and optionally an emulsifier and water.
• a binder composition for a non-aqueous secondary battery electrode is obtained, including a particulate binder having a particulate binder having a particulate binder composition.
• seed polymerization method for example, (meth)acrylic acid ester monomeric units, and optionally acidic functional group-containing monomeric units, unsaturated carboxylic acid amide monomeric units, unsaturated carboxylic acid epoxy monomeric units
• Seed particle weight consisting of a polymer containing any one or more monomer units among the monomer units contained in the polymer (A), such as crosslinkable monomer units, other monomer units, etc.
• the monomer units contained in the polymer (A), water, an emulsifier, a polymerization initiator, and optionally a chain transfer agent are mixed in the coalescence, and a polymerization reaction is performed in the same manner as above to form seeds as a core part. A mixture containing particulate polymer is obtained.
• a monomer for forming a shell portion an aromatic vinyl monomer, and optionally a monomer unit contained in the polymer (C) such as a monomer unit other than the aromatic vinyl monomer unit
• a monomer for forming a shell portion an aromatic vinyl monomer, and optionally a monomer unit contained in the polymer (C) such as a monomer unit other than the aromatic vinyl monomer unit
• Polymerization is continued by continuous addition of polymers (units) and, optionally, emulsifiers and water.
• a polymer (B) containing monomers for forming the surface layer (acidic functional group-containing monomer units, and optionally monomer units other than the acidic functional group-containing monomer units) is added to the mixture.
• Polymerization is continued by successive additions of monomer units), and optionally an emulsifier and water.
• a binder composition for a non-aqueous secondary battery electrode is obtained, including a particulate binder having a particulate binder having a particulate binder composition.
• the method for preparing the binder composition may be carried out, for example, by the following procedure including at least two stages of polymerization.
• Monomers for forming the polymer (A) are mixed with water, an emulsifier, a chain transfer agent, and a polymerization initiator.
• the mixture is heated to carry out a polymerization reaction until a predetermined polymerization conversion rate is reached, thereby forming particulate polymers composed of the polymer (A).
• a monomer for forming the polymer (B), and optionally an emulsifier and water are continuously added to the reaction solution to continue polymerization.
• the reaction is stopped by cooling to obtain a mixture containing a particulate binder. Remove unreacted monomer from the mixture.
• the pH of the mixture is adjusted to be within the above-mentioned preferred pH range, and optionally, the above-mentioned additives (e.g., anti-aging agents) are added to form a structure containing the polymer (B) in the surface layer.
• a binder composition for a non-aqueous secondary battery electrode is obtained, which contains a particulate binder having the above-mentioned properties and water.
• the binder composition When the particulate binder has a core-shell structure containing the polymer (B) in the surface layer part and further having a core part containing the polymer (A) and a shell part containing the polymer (C), the binder composition
• the method for preparing the product may be carried out, for example, by the following procedure involving at least three stages of polymerization. First, in the first stage of polymerization, monomers for forming the polymer (A) are mixed with water, an emulsifier, a chain transfer agent, and a polymerization initiator. The mixture is heated to carry out a polymerization reaction until a predetermined polymerization conversion rate is reached, thereby forming particulate polymers composed of the polymer (A).
• a monomer for forming the polymer (C), and optionally an emulsifier and water are continuously added to the reaction solution to continue the polymerization.
• the reaction is stopped by cooling, and a particulate binder having a core-shell structure having a core portion containing the polymer (A) and a shell portion containing the polymer (C) is prepared.
• a binder composition for a non-aqueous secondary battery electrode containing water is formed.
• a monomer for forming the polymer (B), and optionally an emulsifier and water are continuously added to the reaction solution to continue the polymerization.
• a binder composition for a non-aqueous secondary battery electrode further comprising a particulate binder having a core-shell structure having a core part containing a polymer (A) and a shell part containing a polymer (C), and water. get something
• Examples of the emulsifier used in preparing the binder composition include alkyldiphenyl ether disulfonic acid, dodecylbenzenesulfonic acid, lauryl sulfate, or salts thereof (eg, potassium salt, sodium salt).
• the amount of the emulsifier added is preferably 0.1 parts by mass or more, and preferably 0.2 parts by mass or more, based on 100 parts by mass of the total monomer units of the polymer constituting the particulate binder. More preferably, it is 10 parts by mass or less, and more preferably 5 parts by mass or less.
• Examples of the polymerization initiator used in preparing the binder composition include potassium persulfate, n-butyllithium, and ammonium persulfate.
• the amount of the polymerization initiator added is preferably 0.1 parts by mass or more, and 0.2 parts by mass or more, based on 100 parts by mass of the total monomer units of the polymer constituting the particulate binder. More preferably, it is 10 parts by mass or less, and more preferably 5 parts by mass or less.
• Examples of the chain transfer agent used in preparing the binder composition include ⁇ -methylstyrene dimer, tert-dodecylmercaptan, and 3-mercapto-1,2-propanediol.
• the amount of the chain transfer agent added is preferably 0.1 parts by mass or more, and 0.2 parts by mass or more, based on 100 parts by mass of the total monomer units of the polymer constituting the particulate binder. More preferably, it is 10 parts by mass or less, and more preferably 5 parts by mass or less.
• ⁇ Tackiness of binder composition The binder composition of the present invention described above has good tackiness.
• a SUS probe was pressed against one side of the film formed by drying the binder composition under the conditions of a pressing speed of 3 mm/s, a pressing load: 100 gf, and a pressing holding time of 1 second, and then , means that the tack strength (N) when the SUS probe is pulled up at a pulling speed of 3 mm/s is 8 N or less, preferably 4 N or less.
• the tack strength of the binder composition can be measured by the method described in the Examples of this specification.
• the slurry composition of the present invention is a composition used for forming an electrode composite layer of an electrode, and contains the binder composition of the present invention and an electrode active material, and optionally contains components other than the above components (hereinafter referred to as , referred to as "other components"). Since the slurry composition of the present invention contains the binder composition described above, it has good tackiness as a slurry composition and can form an electrode with excellent peel strength. By using an electrode with excellent peel strength formed using the slurry composition of the present invention, it is possible to make a secondary battery exhibit excellent performance, for example, improve battery characteristics such as cycle characteristics, The internal resistance of the secondary battery can be reduced.
• the amount of the binder composition blended in the slurry composition is not particularly limited.
• the blending amount of the binder composition can be such that the amount of the particulate binder is 0.5 parts by mass or more and 15 parts by mass or less in terms of solid content per 100 parts by mass of the electrode active material.
• the electrode active material is not particularly limited, and known electrode active materials used in secondary batteries can be used.
• the electrode active material that can be used in the electrode composite layer of a lithium ion secondary battery as an example of a secondary battery is not particularly limited, and the following electrode active materials can be used. can.
• Examples of positive electrode active materials to be added to the positive electrode composite layer of the positive electrode of lithium ion secondary batteries include compounds containing transition metals, such as transition metal oxides, transition metal sulfides, and composites of lithium and transition metals. Metal oxides and the like can be used. Note that examples of the transition metal include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Mo.
• the positive electrode active material is not particularly limited, and includes lithium-containing cobalt oxide (LiCoO 2 ), lithium manganate (LiMn 2 O 4 ), lithium-containing nickel oxide (LiNiO 2 ), Co- Ni-Mn lithium-containing composite oxide, Ni-Mn-Al lithium-containing composite oxide, Ni-Co-Al lithium-containing composite oxide, olivine-type lithium iron phosphate (LiFePO 4 ), olivine-type manganese phosphate Lithium (LiMnPO 4 ), lithium-excess spinel compound represented by Li 1+x Mn 2-x O 4 (0 ⁇ X ⁇ 2), Li[Ni 0.17 Li 0.2 Co 0.07 Mn 0.56 ] Examples include O 2 , LiNi 0.5 Mn 1.5 O 4 , and the like. Note that the above-mentioned positive electrode active materials may be used alone or in combination of two or more.
• Examples of the negative electrode active material blended in the negative electrode composite layer of the negative electrode of a lithium ion secondary battery include carbon-based negative electrode active materials, metal-based negative electrode active materials, and negative electrode active materials that are a combination of these.
• the carbon-based negative electrode active material refers to an active material whose main skeleton is carbon and into which lithium can be inserted (also referred to as "doping").
• the carbon-based negative electrode active materials include coke, mesocarbon microbeads (MCMB), mesophase pitch-based carbon fibers, pyrolytic vapor-grown carbon fibers, phenolic resin fired bodies, polyacrylonitrile-based carbon fibers, Examples include carbonaceous materials such as pseudo-isotropic carbon, fired furfuryl alcohol resin (PFA) and hard carbon, and graphite materials such as natural graphite and artificial graphite.
• a metal-based negative electrode active material is an active material that contains metal, and usually contains an element in its structure that allows insertion of lithium, and has a theoretical electric capacity per unit mass of 500 mAh/m when lithium is inserted. It refers to an active material that is more than 100 g.
• metal-based active materials include lithium metal, single metals that can form lithium alloys (such as Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni, P, Pb, Sb, and Si). , Sn, Sr, Zn, Ti, etc.) and their oxides, sulfides, nitrides, silicides, carbides, and phosphides. Further examples include oxides such as lithium titanate.
• active materials containing silicon are preferred. This is because by using a silicon-based negative electrode active material, the capacity of a lithium ion secondary battery can be increased.
• silicon-based negative electrode active materials include silicon (Si), alloys of silicon and cobalt, nickel, iron, etc., SiO x , mixtures of Si-containing materials and carbon materials, Si-containing materials coated with conductive carbon, or Examples include a composite of a Si-containing material and conductive carbon.
• SiO x is a compound containing at least one of SiO and SiO 2 and Si, and x is usually 0.01 or more and less than 2.
• SiO x can be formed using, for example, a disproportionation reaction of silicon monoxide (SiO).
• SiO x can be prepared by heat treating SiO, optionally in the presence of a polymer such as polyvinyl alcohol, to produce silicon and silicon dioxide. Note that the heat treatment can be performed in an inert gas atmosphere after pulverizing and mixing SiO and optionally a polymer.
• a Si-containing material such as silicon or SiO x and a carbon material such as a carbonaceous material or a graphite material are pulverized and mixed optionally in the presence of a polymer such as polyvinyl alcohol.
• a polymer such as polyvinyl alcohol.
• the carbonaceous material and graphite material materials that can be used as a carbon-based negative electrode active material can be used.
• Examples of composites of Si-containing materials and conductive carbon include compounds obtained by heat-treating a pulverized mixture of SiO, a polymer such as polyvinyl alcohol, and optionally a carbon material under an inert gas atmosphere. be able to.
• SiO A complex Si-SiO x -C complex
• SiO--C composite in which part of the Si in SiO is replaced with conductive carbon
• negative electrode active materials may be used alone or in combination of two or more.
• ⁇ Other ingredients Other components that may be incorporated into the slurry composition include, without particular limitation, a dispersant, a viscosity modifier (thickener), a phosphite antioxidant, a metal scavenger, a conductive material, and the like. In addition, one type of other components may be used alone, or two or more types may be used in combination in any ratio.
• a slurry composition is prepared by mixing a binder composition, an electrode active material, and other components used as necessary in the presence of an aqueous phase (aqueous medium) that is normally included in the binder composition. be able to.
• the mixing method is not particularly limited, but mixing can be performed using a commonly used stirrer or disperser.
• the electrode for a nonaqueous secondary battery of the present invention includes an electrode mixture layer formed using the slurry composition for a nonaqueous secondary battery electrode described above. Therefore, the electrode composite material layer is made of a dried product of the slurry composition described above, and usually contains an electrode active material and a component derived from a particulate binder, and optionally further contains other components. .
• each component contained in the electrode mixture layer was contained in the slurry composition for non-aqueous secondary battery electrodes, and the preferred abundance ratio of each component is determined according to the slurry composition. It is the same as the preferred abundance ratio of each component in the product.
• the particulate binder exists in the form of particles in the slurry composition, but in the electrode composite material layer formed using the slurry composition, it may be in the form of particles or in any other form. It may be a shape.
• the non-aqueous secondary battery electrode of the present invention has excellent peel strength because the electrode mixture layer is formed using the above-mentioned slurry composition for non-aqueous secondary battery electrodes. . Therefore, a non-aqueous secondary battery equipped with the electrode for a non-aqueous secondary battery of the present invention can exhibit excellent performance, for example, has excellent battery characteristics such as cycle characteristics, and has a reduced internal resistance. .
• the electrode composite material layer of the electrode for a non-aqueous secondary battery of the present invention can be formed using, for example, the following method. 1) A method of applying the slurry composition of the present invention to the surface of a current collector and then drying it; 2) A method of immersing a current collector in the slurry composition of the present invention and then drying it; and 3) Applying the slurry composition of the present invention onto a release base material and drying it to produce an electrode composite layer. A method of transferring the obtained electrode mixture layer to the surface of a current collector. Among these, method 1) is particularly preferred because it allows easy control of the layer thickness of the electrode composite material layer.
• the method 1) includes a step of applying a slurry composition onto a current collector (coating step), and drying the slurry composition applied onto the current collector to form an electrode on the current collector. It includes a step of forming a composite material layer (drying step).
• the method for applying the slurry composition onto the current collector is not particularly limited, and any known method can be used. Specifically, as a coating method, a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating method, etc. can be used. At this time, the slurry composition may be applied to only one side of the current collector, or may be applied to both sides. The thickness of the slurry film on the current collector after coating and before drying can be appropriately set depending on the thickness of the electrode mixture layer obtained by drying.
• the slurry composition of the present invention even when electrodes are manufactured by coating the slurry composition on a current collector at high speed, the formed electrodes can exhibit excellent peel strength. Therefore, the above slurry composition can be used for high-speed coating.
• the current collector to which the slurry composition is applied a material that has electrical conductivity and is electrochemically durable is used.
• a current collector for example, a current collector made of iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum, etc. can be used. Note that the above-mentioned materials may be used alone or in combination of two or more in any ratio.
• the method for drying the slurry composition on the current collector is not particularly limited, and any known method can be used, such as drying with warm air, hot air, low humidity air, vacuum drying, infrared rays, electron beams, etc. A drying method by irradiation can be used.
• a drying method by irradiation can be used.
• the electrode composite material layer may be subjected to pressure treatment using a mold press, a roll press, or the like.
• the pressure treatment can improve the adhesion between the electrode composite material layer and the current collector, and increase the density of the obtained electrode composite material layer.
• the electrode composite material layer contains a curable polymer, it is preferable to harden the polymer after forming the electrode composite material layer.
• the non-aqueous secondary battery of the present invention includes a positive electrode, a negative electrode, an electrolyte, and a separator, and uses the above-described electrode for non-aqueous secondary batteries as at least one of the positive electrode and the negative electrode. Since the non-aqueous secondary battery of the present invention is manufactured using the above-described non-aqueous secondary battery electrode as at least one of the positive electrode and the negative electrode, it can exhibit excellent performance, such as cycle characteristics. It has excellent battery characteristics such as, and has a reduced internal resistance.
• a secondary battery is a lithium ion secondary battery is demonstrated below as an example, this invention is not limited to the following example.
• the electrodes other than the above-described electrodes for non-aqueous secondary batteries of the present invention that can be used in the non-aqueous secondary battery of the present invention are not particularly limited, and may be used in the production of secondary batteries. Any known electrode can be used. Specifically, as an electrode other than the electrode for a non-aqueous secondary battery of the present invention described above, an electrode formed by forming an electrode mixture layer on a current collector using a known manufacturing method can be used. can.
• an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is usually used.
• a lithium salt is used as a supporting electrolyte for a lithium ion secondary battery.
• lithium salts include 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 preferred because they are easily soluble in solvents and exhibit a high degree of dissociation.
• one type of electrolyte may be used alone, or two or more types may be used in combination in any ratio.
• the lithium ion conductivity tends to increase as a supporting electrolyte with a higher degree of dissociation is used, so the lithium ion conductivity can be adjusted depending on the type of supporting electrolyte.
• the organic solvent used in the electrolyte is not particularly limited as long as it can dissolve the supporting electrolyte, but examples include dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), Carbonates such as butylene carbonate (BC), ethylmethyl carbonate (EMC), and vinylene carbonate (VC); Esters such as ⁇ -butyrolactone and methyl formate; Ethers such as 1,2-dimethoxyethane and tetrahydrofuran; Sulfolane and dimethyl Sulfur-containing compounds such as sulfoxide are preferably used. Alternatively, a mixture of these solvents may be used.
• DMC dimethyl carbonate
• EC ethylene carbonate
• DEC diethyl carbonate
• PC propylene carbonate
• Carbonates such as butylene carbonate (BC), ethylmethyl carbonate (EMC), and vinylene carbonate (VC)
• Esters such as
• carbonates because they have a high dielectric constant and a wide stable potential range.
• the lower the viscosity of the solvent used the higher the lithium ion conductivity tends to be, so the lithium ion conductivity can be adjusted depending on the type of solvent.
• concentration of the electrolyte in the electrolytic solution can be adjusted as appropriate.
• known additives can be added to the electrolyte.
• the separator is not particularly limited, and for example, those described in JP-A No. 2012-204303 can be used. Among these, polyolefin-based ( A microporous membrane made of a resin such as polyethylene, polypropylene, polybutene, or polyvinyl chloride is preferred.
• a positive electrode and a negative electrode are stacked on top of each other with a separator interposed therebetween, and this is rolled or folded according to the shape of the battery as necessary, and then placed in a battery container. It can be manufactured by injecting an electrolyte into the container and sealing it.
• the above-mentioned electrode for non-aqueous secondary batteries is used as at least one of the positive electrode and the negative electrode, preferably as the negative electrode.
• non-aqueous secondary battery of the present invention may be provided with an overcurrent prevention element such as a fuse or a PTC element, as necessary, in order to prevent pressure rise inside the secondary battery, overcharging and discharging, etc.
• an overcurrent prevention element such as a fuse or a PTC element
• Expanded metal, lead plates, etc. may also be provided.
• the shape of the secondary battery may be, for example, a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, a flat shape, or the like.
• ⁇ Viscosity of binder composition The solid content concentration of the obtained binder composition was adjusted to 30% by mass by adding water or removing water by concentration, and the pH was adjusted to 6.0 or 8.0 by adding hydrochloric acid or sodium hydroxide as necessary. After adjusting the binder composition, the viscosity of the binder composition was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name "TVB-10", rotation speed: 60 rpm). The temperature during viscosity measurement was 25°C.
• ⁇ Tackiness of binder composition The binder composition was applied onto copper foil so that the film thickness after drying was 5 ⁇ m, and dried at 110° C. for 5 minutes to produce a binder film.
• the produced film was cut into a size of 30 mm x 20 mm to prepare a test piece.
• a SUS probe (10 mm ⁇ ) was pressed against one surface of the test piece under the conditions of a pressing speed of 3 mm/s, pressing load: 100 gf, and pressing holding time of 1 second, and then a pulling speed of 3 mm/s. s, the tack strength (N) when the SUS probe was pulled up was measured and evaluated according to the following criteria. The lower the tack strength, the better the productivity because it will not stick to the dryer, etc.
• Tack strength is 4N or less
• B Tack strength is greater than 4N and less than 8N
• C Tack strength is greater than 8N
• ⁇ Negative electrode peel strength> The produced negative electrode was cut into a rectangle with a length of 100 mm and a width of 10 mm to prepare a test piece. Cellophane tape was attached to the surface of the negative electrode composite material layer of this test piece with the surface of the negative electrode composite material layer facing down. At this time, the cellophane tape specified in JIS Z1522 was used. In addition, cellophane tape was fixed to the test stand. Thereafter, one end of the current collector was pulled vertically upward at a pulling speed of 50 mm/min and the stress was measured when it was peeled off. This measurement was performed three times, the average value was determined, and the peel strength was evaluated using the average value as the peel strength according to the following criteria. A: Peel strength is 10 N/m or more B: Peel strength is 7 N/m or more and less than 10 N/m C: Peel strength is less than 7 N/m
• the battery voltage after 15 seconds on the charging side was plotted against the current value, and the slope was determined as the IV resistance ( ⁇ ).
• the obtained IV resistance value ( ⁇ ) was compared with the IV resistance of Comparative Example 7, and evaluated based on the following criteria. Note that the smaller the value of the IV resistance, the lower the internal resistance of the secondary battery.
• ⁇ Cycle characteristics of lithium ion secondary batteries> The lithium ion secondary batteries produced in Examples and Comparative Examples were left standing at a temperature of 25° C. for 5 hours after injecting the electrolyte. Next, the battery was charged to a cell voltage of 3.65 V using a constant current method at a temperature of 25° C. and 0.2 C, and then an aging treatment was performed at a temperature of 60° C. for 12 hours. Then, the battery was discharged to a cell voltage of 3.00 V using a constant current method at a temperature of 25° C. and 0.2 C.
• aqueous dispersion (a binder composition for a negative electrode of a lithium ion secondary battery) containing a particulate binder having a structure containing the polymer obtained above and water was obtained.
• the average particle diameter Da of the particulate binder at pH 6.0 and 8.0 was measured by dynamic light scattering method, and the volume average particle size was measured by laser diffraction scattering method.
• the diameter Db and the tackiness of the binder composition were measured or evaluated. The results are shown in Table 1.
• the resulting mixture was adjusted to a solid content concentration of 60% with ion-exchanged water, and then mixed at 25° C. for 60 minutes. Next, after adjusting the solid content concentration to 52% with ion-exchanged water, the mixture was further mixed at 25° C. for 15 minutes to obtain a mixed solution. 2.0 parts equivalent to the solid content of the binder composition prepared above and ion-exchanged water were added to the resulting mixed solution, and the final solid content concentration was adjusted to 48%. After further mixing for 10 minutes, a defoaming treatment was performed under reduced pressure to obtain a slurry composition for a negative electrode with good fluidity.
• the obtained negative electrode slurry composition was coated with a comma coater on a 15 ⁇ m thick copper foil serving as a current collector at a speed of 1.2 m/min (normal speed) so that the basis weight after drying was 10.5 mg. / cm2 and dried. This drying was performed by transporting the copper foil at a speed of 1.2 m/min in a 120°C oven for 1 minute and in a 130°C oven for 1 minute.
• the obtained negative electrode original fabric was rolled with a roll press to obtain a negative electrode (negative electrode at normal coating speed) in which the density of the negative electrode composite layer was 1.70 g/cm 3 . Then, the peel strength of the negative electrode was evaluated. The results are shown in Table 1.
• the speed at which the slurry composition is applied onto the copper foil was changed from 1.2 m/min to 3.6 m/min (high speed), and the conveyance speed during drying was also changed from 1.2 m/min to 3.6 m/min (high speed).
• the same operation as above was performed except that the speed was changed to 6 m/min and the material was transported in an oven at 120 °C for 20 seconds and then in an oven at 150 °C for 20 seconds to obtain a negative electrode manufactured by high-speed coating. Ta.
• the peel strength of the negative electrode produced by high-speed coating was evaluated. The results are shown in Table 1.
• the obtained slurry composition for a positive electrode was applied onto a 20 ⁇ m thick aluminum foil serving as a current collector using a comma coater so that the drying basis weight was 23 mg/cm 2 and was dried. This drying was performed by transporting the aluminum foil at a speed of 0.5 m/min in an oven at 60° C. for 2 minutes. Thereafter, heat treatment was performed at 120° C. for 2 minutes to obtain a positive electrode original fabric. Then, the original positive electrode fabric was rolled using a roll press to obtain a positive electrode with a positive electrode composite layer having a density of 4.0 g/cm 3 .
• the obtained flat body had an elliptical shape in plan view, and the ratio of the major axis to the minor axis (major axis/minor axis) was 7.7.
• EC ethylene carbonate
• EMC ethyl methyl carbonate
• the opening of the laminate case was sealed with heat to produce a laminated lithium ion secondary battery as a non-aqueous secondary battery.
• the obtained secondary battery was in the form of a pouch with a width of 35 mm x height of 48 mm x thickness of 5 mm, and a nominal capacity of 700 mAh. Then, the internal resistance and cycle characteristics of this lithium ion secondary battery were evaluated. The results are shown in Table 1.
• Example 2 When preparing a binder composition containing a particulate binder, the composition of the monomers used in the first stage polymerization was changed to 78.0 parts of butyl acrylate as a (meth)acrylic acid ester monomer, and 78.0 parts of ethylenic monomer. Except that the saturated carboxylic acid monomer was changed to 1.0 parts of methacrylic acid, the unsaturated carboxylic acid amide monomer was changed to 1.5 parts of N-methylolacrylamide, and the other monomers were changed to 1.5 parts of acrylonitrile.
• Example 2 In the same manner as in Example 1, a binder composition containing a particulate binder, a slurry composition for a non-aqueous secondary battery negative electrode, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and measurements and evaluations were performed. Ta. The results are shown in Table 1.
• Example 3 When preparing a binder composition containing a particulate binder, the composition of the monomers used in the first stage polymerization was changed to 78.0 parts of butyl acrylate as a (meth)acrylic acid ester monomer, and 78.0 parts of ethylenic monomer. 1.0 parts of methacrylic acid as a saturated carboxylic acid monomer, 1.5 parts of allyl glycidyl ether as a crosslinking monomer (unsaturated carboxylic acid epoxy monomer), and 1.5 parts of acrylonitrile as other monomers.
• a binder composition containing a particulate binder, a slurry composition for a non-aqueous secondary battery negative electrode, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared in the same manner as in Example 1, except for the changes. , measured and evaluated. The results are shown in Table 1.
• Example 4 When preparing a binder composition containing a particulate binder, the composition of the monomers used in the first stage polymerization was changed to 76.5 parts of butyl acrylate as a (meth)acrylic acid ester monomer, and 76.5 parts of ethylenic monomer. 1.0 parts of methacrylic acid as a saturated carboxylic acid monomer, 1.5 parts of N-methylolacrylamide as an unsaturated carboxylic acid amide monomer, 1.5 parts of allyl glycidyl ether as an unsaturated carboxylic acid epoxy monomer, and others.
• a binder composition containing a particulate binder, a slurry composition for a non-aqueous secondary battery negative electrode, a negative electrode, and a positive electrode were prepared in the same manner as in Example 1, except that 1.5 parts of acrylonitrile was used as the monomer. , fabricated or prepared lithium ion secondary batteries, and conducted measurements and evaluations. The results are shown in Table 1.
• Example 5 When preparing a binder composition containing a particulate binder, the amount of butyl acrylate used as a (meth)acrylic acid ester monomer used in the first stage polymerization was increased from 76.5 parts to 74.5 parts. The procedure was the same as in Example 4, except that the amount of methacrylic acid added as the ethylenically unsaturated carboxylic acid monomer used in the third stage polymerization was changed from 3.0 parts to 5.0 parts. A binder composition containing a particulate binder, a slurry composition for a non-aqueous secondary battery negative electrode, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and then measured and evaluated. The results are shown in Table 1.
• Example 6 When preparing a binder composition containing a particulate binder, the amount of butyl acrylate used as a (meth)acrylic acid ester monomer used in the first stage polymerization was increased from 59.5 parts to 75.5 parts. The procedure was the same as in Example 4, except that the amount of methacrylic acid added as the ethylenically unsaturated carboxylic acid monomer used in the third stage polymerization was changed from 3.0 parts to 20.0 parts. A binder composition containing a particulate binder, a slurry composition for a non-aqueous secondary battery negative electrode, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and then measured and evaluated. The results are shown in Table 1.
• Example 7 Except that when preparing the binder composition containing the particulate binder, the amount of sodium dodecylbenzenesulfonate used as an emulsifier used in the first stage polymerization was changed from 0.3 parts to 0.9 parts.
• a binder composition containing a particulate binder, a slurry composition for a nonaqueous secondary battery negative electrode, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and measurements and evaluations were performed. went. The results are shown in Table 1.
• Example 8 When preparing a binder composition containing a particulate binder, the amount of butyl acrylate used as a (meth)acrylic acid ester monomer used in the first stage polymerization was increased from 76.5 parts to 91.5 parts.
• a binder composition containing a particulate binder, a slurry composition for a non-aqueous secondary battery negative electrode, a negative electrode, a positive electrode, A lithium ion secondary battery was manufactured or prepared, and then measured and evaluated. The results are shown in Table 1.
• Example 2 In the same manner as in Example 1, a binder composition containing a particulate binder, a slurry composition for a nonaqueous secondary battery negative electrode, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and then measured and evaluated. The results are shown in Table 1.
• a binder composition containing a particulate binder was prepared in the same manner as in Example 4, except that the polymer was changed to 1.0 part of acrylonitrile and the second-stage polymerization and third-stage polymerization were not performed.
• a slurry composition for a negative electrode of a non-aqueous secondary battery, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and then measured and evaluated. The results are shown in Table 1.
• Example 1 In the same manner as in Example 1, a binder composition containing a particulate binder, a slurry composition for a non-aqueous secondary battery negative electrode, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and measurements and evaluations were performed. . The results are shown in Table 1.
• the polymer was changed to 1.5 parts of acrylonitrile, and the second stage polymerization was carried out by changing the monomer composition to 45.0 parts of styrene as an aromatic vinyl monomer and an ethylenically unsaturated carboxylic acid monomer.
• a binder composition containing a particulate binder and a non-aqueous secondary battery negative electrode were prepared in the same manner as in Example 1, except that 1.0 parts of methacrylic acid was used and the third stage polymerization was not performed.
• a slurry composition, a negative electrode, a positive electrode, and a lithium ion secondary battery were produced or prepared, and then measured and evaluated. The results are shown in Table 1.
• Table 1 shows that by using the binder compositions prepared in Examples 1 to 7, which are within the scope of the present invention, it is possible to form electrodes for non-aqueous secondary batteries with excellent peel strength and good tack properties. It can be seen that it is possible to provide a binder composition for a non-aqueous secondary battery electrode having the following.
• the present invention it is possible to form a non-aqueous secondary battery electrode with excellent peel strength, and to provide a binder composition for a non-aqueous secondary battery electrode that has good tackiness. Further, according to the present invention, it is possible to provide a slurry composition for a non-aqueous secondary battery electrode that can form an electrode for a non-aqueous secondary battery with excellent peel strength. Further, according to the present invention, it is possible to provide an electrode for a non-aqueous secondary battery that has excellent peel strength, and a non-aqueous secondary battery that includes the electrode for a non-aqueous secondary battery.

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