Classifications

• • 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
  • 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
  • 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
• • 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
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/12—Esters of monohydric alcohols or phenols
  • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
  • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
  • C08F220/1804—C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
• • 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
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/52—Amides or imides
  • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
  • C08F220/56—Acrylamide; Methacrylamide
• • 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
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/52—Amides or imides
  • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
  • C08F220/58—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
  • C08L101/02—Compositions of unspecified macromolecular compounds characterised by the presence of specified groups, e.g. terminal or pendant functional groups
  • C08L101/025—Compositions of unspecified macromolecular compounds characterised by the presence of specified groups, e.g. terminal or pendant functional groups containing nitrogen atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
  • C08L101/02—Compositions of unspecified macromolecular compounds characterised by the presence of specified groups, e.g. terminal or pendant functional groups
  • C08L101/06—Compositions of unspecified macromolecular compounds characterised by the presence of specified groups, e.g. terminal or pendant functional groups containing oxygen atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/24—Homopolymers or copolymers of amides or imides
  • C08L33/26—Homopolymers or copolymers of acrylamide or methacrylamide
• • 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
  • H01M10/60—Heating or cooling; Temperature control
  • H01M10/65—Means for temperature control structurally associated with the cells
  • H01M10/658—Means for temperature control structurally associated with the cells by thermal insulation or shielding
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
  • C08K2003/2227—Oxides; Hydroxides of metals of aluminium
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/30—Sulfur-, selenium- or tellurium-containing compounds
  • C08K2003/3045—Sulfates
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to a binder composition for a heat-resistant layer of a non-aqueous secondary battery, a slurry composition for a heat-resistant layer of a non-aqueous secondary battery, a heat-resistant layer for a non-aqueous secondary battery, and a non-aqueous secondary battery.
• Non-aqueous secondary batteries such as lithium-ion secondary batteries (hereinafter, may be simply abbreviated as "secondary batteries") are small and lightweight, have high energy density, and can be repeatedly charged and discharged. Yes, it is used for a wide range of purposes.
• the secondary battery generally includes a battery member such as an electrode (positive electrode and negative electrode) and a separator that separates the positive electrode and the negative electrode.
• a protective layer for improving heat resistance that is, a battery member provided with a heat resistant layer has been conventionally used.
• examples of the heat-resistant layer of the secondary battery include those formed by binding non-conductive inorganic particles such as alumina with a binder.
• a heat-resistant layer is usually referred to as a slurry composition in which non-conductive inorganic particles or a binder are dissolved or dispersed in a dispersion medium such as water (hereinafter, referred to as “non-aqueous secondary battery heat-resistant layer slurry composition"). It may be abbreviated as "slurry composition for heat-resistant layer”), and this slurry composition for heat-resistant layer is formed by applying and drying it on a base material such as a separator base material or an electrode base material.
• Patent Document 1 discloses a binder composition for a porous membrane of a secondary battery containing a polycarboxylic acid and water having predetermined properties, and the binder composition for a porous membrane of a secondary battery is storage-stable. It has been reported that a secondary battery having high properties and a porous film for a secondary battery manufactured by using the same can be easily applied and has improved performance such as high temperature cycle characteristics.
• the slurry is improved while improving the dispersion stability of the slurry composition prepared by using the binder composition.
• the heat-resistant layer obtained by using the above-mentioned conventional binder composition has further improved heat-resistant shrinkage.
• the present invention is not capable of preparing a slurry composition for a non-aqueous secondary battery heat-resistant layer capable of forming a heat-resistant layer for a non-aqueous secondary battery excellent in dispersion stability and coatability and excellent heat shrinkage.
• An object of the present invention is to provide a binder composition for a heat-resistant layer of an aqueous secondary battery.
• Another object of the present invention is to provide a slurry composition for a non-aqueous secondary battery heat-resistant layer capable of forming a heat-resistant layer for a non-aqueous secondary battery having excellent dispersion stability and coatability and excellent heat-resistant shrinkage.
• An object of the present invention is to provide a heat-resistant layer for a non-aqueous secondary battery having excellent heat-resistant shrinkage, and a non-aqueous secondary battery provided with the heat-resistant layer.
• the present inventor has conducted diligent studies for the purpose of solving the above problems. Then, the present inventor contains an amide group-containing monomer unit, an acid group-containing monomer unit, and a hydroxyl group-containing monomer unit, and the amide group-containing monomer unit and the acid group-containing monomer unit.
• a binder composition containing a water-soluble polymer having a content ratio within a predetermined range and water a slurry composition having excellent dispersion stability and coatability and a heat-resistant layer having excellent heat shrinkage are formed. We found that it was possible and completed the present invention.
• the present invention aims to advantageously solve the above problems, and the binder composition for a heat-resistant layer of a non-aqueous secondary battery of the present invention is a non-aqueous polymer containing a water-soluble polymer and water.
• the content ratio of the amide group-containing monomer unit in the polymer is 63% by mass or more and 98% by mass or less, and the content ratio of the acid group-containing monomer unit is 1% by mass or more and 20% by mass or less.
• the amide group-containing monomer unit, the acid group-containing monomer unit, and the hydroxyl group-containing monomer unit are contained, and the content ratio of the amide group-containing monomer unit and the acid group-containing monomer unit is According to the binder composition containing the water-soluble polymer and water, which are within the above ranges, a slurry composition having excellent dispersion stability and coatability can be prepared. Further, according to the slurry composition prepared in this way, a heat-resistant layer having excellent heat-resistant shrinkage can be satisfactorily formed.
• "containing a monomer unit” means that "a polymer obtained by using the monomer contains a repeating unit derived from a monomer". To do.
• the "content ratio (mass%)" of each monomer unit (each repeating unit) contained in the polymer is determined by a nuclear magnetic resonance (NMR) method such as 1 H-NMR or 13 C-NMR. Can be measured using.
• NMR nuclear magnetic resonance
• the content ratio of the hydroxyl group-containing monomer unit in the water-soluble polymer is 1% by mass or more and 25% by mass or less. preferable.
• the content ratio of the hydroxyl group-containing monomer unit in the water-soluble polymer is within the above range, the dispersion stability and coatability of the slurry composition are further improved, and the heat shrinkage of the heat-resistant layer is further improved. Can be enhanced.
• the hydroxyl group-containing monomer unit is a hydroxyl group-containing (meth) acrylamide monomer unit. If the hydroxyl group-containing monomer unit contained in the water-soluble polymer in the binder composition is a hydroxyl group-containing (meth) acrylamide monomer unit, the heat-resistant layer reduces the amount of water carried into the secondary battery. At the same time, the heat-resistant shrinkage of the heat-resistant layer can be further enhanced. In addition, the cycle characteristics of the secondary battery can be improved.
• "(meth) acrylic” means acrylic and / or methacrylic.
• the binder composition for the heat-resistant layer of a non-aqueous secondary battery of the present invention is a molar of the content ratio of the hydroxyl group-containing monomer unit to the content ratio of the acid group-containing monomer unit in the water-soluble polymer.
• the ratio is preferably 0.70 or more.
• the molar ratio of the content ratio of the hydroxyl group-containing monomer unit to the content ratio of the acid group-containing monomer unit in the water-soluble polymer (hereinafter, may be abbreviated as "hydroxyl group / acid group molar ratio").
• hydroxyl group / acid group molar ratio When is greater than or equal to the above value, the dispersion stability and coatability of the slurry composition can be further improved.
• the "hydroxyl group / acid group molar ratio" is the content ratio of the acid group-containing monomer unit by using a nuclear magnetic resonance (NMR) method such as 1 H-NMR or 13 C-NMR.
• NMR nuclear magnetic resonance
• the content ratio (mol%) of the hydroxyl group-containing monomer unit (mol%) can be measured and calculated from these measured values.
• the weight average molecular weight of the water-soluble polymer is preferably 200,000 or more and 2,000,000 or less.
• the coatability of the slurry composition can be further improved and the heat-resistant shrinkage of the heat-resistant layer can be further improved.
• the weight average molecular weight of the water-soluble polymer can be measured by gel permeation chromatography (GPC).
• the binder composition for the heat-resistant layer of the non-aqueous secondary battery of the present invention further contains a particulate polymer. If the binder composition contains a particulate polymer, the adhesion between the heat-resistant layer obtained by using the binder composition and the base material can be improved. In addition, the cycle characteristics of the secondary battery can be made excellent.
• the present invention aims to advantageously solve the above problems, and the slurry composition for a heat-resistant layer of a non-aqueous secondary battery of the present invention includes non-conductive inorganic particles and any of the above-mentioned ones. It is characterized by containing a binder composition for a heat-resistant layer of a non-aqueous secondary battery.
• the slurry composition containing the non-conductive inorganic particles and any of the above-mentioned binder compositions is excellent in dispersion stability and coatability. Further, according to the slurry composition, a heat-resistant layer having excellent heat-resistant shrinkage can be formed.
• An object of the present invention is to solve the above problems advantageously, and the heat-resistant layer for a non-aqueous secondary battery of the present invention uses the above-mentioned slurry composition for a non-aqueous secondary battery heat-resistant layer. It is characterized in that it is formed. As described above, the heat-resistant layer formed from the above-mentioned slurry composition has excellent heat-resistant shrinkage.
• the present invention also has an object of advantageously solving the above-mentioned problems, and the non-aqueous secondary battery of the present invention is characterized by including the above-mentioned heat-resistant layer for a non-aqueous secondary battery. As described above, the safety of the secondary battery including the battery member having the heat-resistant layer described above is sufficiently ensured.
• a slurry composition for a non-aqueous secondary battery heat-resistant layer capable of forming a heat-resistant layer for a non-aqueous secondary battery which is excellent in dispersion stability and coatability and also excellent in heat shrinkage.
• a binder composition for a heat-resistant layer of an aqueous secondary battery can be provided.
• a slurry composition for a non-aqueous secondary battery heat-resistant layer capable of forming a heat-resistant layer for a non-aqueous secondary battery having excellent dispersion stability and coatability and excellent heat-resistant shrinkage. can do.
• the binder composition for the non-aqueous secondary battery heat-resistant layer of the present invention can be used for preparing the slurry composition for the non-aqueous secondary battery heat-resistant layer of the present invention.
• the slurry composition for a heat-resistant layer of a non-aqueous secondary battery of the present invention can be used for forming a heat-resistant layer of a non-aqueous secondary battery such as a lithium ion secondary battery.
• the heat-resistant layer for a non-aqueous secondary battery of the present invention is characterized by being formed from the slurry composition for a non-aqueous secondary battery heat-resistant layer of the present invention.
• the non-aqueous secondary battery of the present invention is characterized by including a heat-resistant layer for a non-aqueous secondary battery prepared by using the slurry composition for a non-aqueous secondary battery heat-resistant layer of the present invention.
• the binder composition of the present invention contains a water-soluble polymer and water as a dispersion medium, and optionally further contains a particulate polymer and other components.
• the above-mentioned water-soluble polymer contains an amide group-containing monomer unit, an acid group-containing monomer unit, and a hydroxyl group-containing monomer unit, and the amide group is contained.
• the content ratio of the contained monomer unit is 63% by mass or more and 98% by mass or less, and the content ratio of the acid group-containing monomer unit is 1% by mass or more and 20% by mass or less.
• the binder composition of the present invention contains an amide group-containing monomer unit, an acid group-containing monomer unit, and a hydroxyl group-containing monomer unit in water, and the amide group-containing monomer unit and the said. Since each contains a water-soluble polymer in which the content ratio of the acid group-containing monomer unit is within the above-mentioned range, if the binder composition is used, a slurry composition having excellent dispersion stability and coatability can be obtained. In addition to being able to be prepared, a heat-resistant layer having excellent heat-resistant shrinkage can be formed. As described above, the reason why the above effect can be obtained by using the binder composition in which the above-mentioned water-soluble polymer is dissolved in water is not clear, but it is presumed to be as follows.
• the amide group-containing monomer unit contained in the water-soluble polymer in the binder composition functions as a main skeleton that imparts high rigidity to the water-soluble polymer, thereby improving the heat-resistant shrinkage of the obtained heat-resistant layer. It is thought that it can be improved.
• the acid group-containing monomer unit contained in the water-soluble polymer in the binder composition is bonded to the non-conductive inorganic particles in the slurry through electrostatic interaction, so that the non-conductive inorganic particles are present. Functions as an adsorption site for particles.
• the non-conductive inorganic particles may aggregate and the dispersion stability of the non-conductive inorganic particles in the slurry may decrease. is there.
• the water-soluble polymer further contains a hydroxyl group-containing monomer unit, the acid group-containing monomer unit as described above is excessive with respect to the non-conductive inorganic particles due to the hydration effect of the hydroxyl group. Adsorption can be suppressed. Therefore, it is considered that the dispersion stability of the non-conductive inorganic particles in the slurry can be improved.
• the slurry composition having excellent dispersion stability can be uniformly applied onto the base material without variation in the amount of coating, and the resulting heat-resistant layer has defective parts (streaks, uneven coating, cissing, etc.). It is considered that the slurry composition is also excellent in coatability because the above-mentioned slurry composition does not occur. Therefore, if the binder composition of the present invention is used, a slurry composition having excellent dispersion stability and coatability can be obtained. Further, according to the slurry composition prepared by using the binder composition of the present invention, a heat-resistant layer having excellent heat-resistant shrinkage can be obtained.
• the water-soluble polymer contained in the binder composition for the heat-resistant layer of a non-aqueous secondary battery is a component in the slurry composition that can contribute to the dispersion stability and the improvement of coatability of the slurry composition. Further, the water-soluble polymer is a component that can also function as a binder in the heat-resistant layer formed by using the slurry composition, and the heat-resistant layer formed by using the slurry composition containing the binder composition. The non-conductive inorganic particles contained in the heat-resistant layer can be held so as not to be separated from the heat-resistant layer.
• "water-soluble" means that when 0.5 g of the polymer is dissolved in 100 g of water at a temperature of 25 ° C., the insoluble content is less than 1.0% by mass. Say.
• the water-soluble polymer contains an amide group-containing monomer unit and an acid group-containing monomer unit at a ratio within a predetermined range, and further contains a hydroxyl group-containing monomer unit.
• the water-soluble polymer includes repeating units other than the amide group-containing monomer unit, the acid group-containing monomer unit, and the hydroxyl group-containing monomer unit (hereinafter, referred to as “other repeating units”). It may be included.
• amide group-containing monomer unit Examples of the amide group-containing monomer capable of forming an amide group-containing monomer unit include N-vinylacetamide, (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, and N-methoxymethyl (meth). ) Acrylamide, dimethylaminopropyl (meth) acrylamide and the like. Among these, acrylamide and methacrylamide are preferable, and acrylamide is more preferable, from the viewpoint of further enhancing the heat shrinkage of the heat-resistant layer.
• the amide group-containing monomer may be used alone or in combination of two or more.
• the monomer unit having both an amide group and a hydroxyl group is included in the "hydroxyl group-containing monomer unit” and not included in the "amide group-containing monomer unit".
• a monomer unit having both an amide group and an acid group is included in the "acid group-containing monomer unit” and is "amide”. It shall not be included in the "group-containing monomer unit”.
• the water-soluble polymer used in the present invention has an amide group-containing monomer unit content of 63 when the amount of all repeating units (all monomer units) in the water-soluble polymer is 100% by mass. It is necessary to be by mass% or more and 98% by mass or less, and the content ratio of the amide group-containing monomer unit in the water-soluble polymer is preferably 67% by mass or more, and more preferably 71% by mass or more. It is more preferably 74% by mass or more, more preferably 95% by mass or less, and even more preferably 90% by mass or less.
• the content of the amide group-containing monomer unit in the water-soluble polymer is less than 63% by mass, the rigidity of the water-soluble polymer is lowered, so that the heat-resistant shrinkage of the heat-resistant layer cannot be sufficiently ensured.
• the content ratio of the amide group-containing monomer unit in the water-soluble polymer is more than 98% by mass, the dispersion stability of the slurry composition is lowered.
• Acid group-containing monomer unit Examples of the acid group-containing monomer capable of forming the acid group-containing monomer unit include a carboxylic acid group-containing monomer, a sulfonic acid group-containing monomer, and a phosphoric acid group-containing monomer. it can.
• the acid group contained in the acid group-containing monomer unit may form a salt with an alkali metal, ammonia, or the like.
• examples of the carboxylic acid group-containing monomer capable of forming a carboxylic acid group-containing monomer unit include monocarboxylic acid and its derivative, dicarboxylic acid and its acid anhydride, and their derivatives.
• examples of the monocarboxylic acid include acrylic acid, methacrylic acid, and crotonic acid.
• examples of the monocarboxylic acid derivative include 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid and the like.
• examples of the dicarboxylic acid include maleic acid, fumaric acid, and itaconic acid.
• Dicarboxylic acid derivatives include methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromalic acid, dichloromaleic acid, fluoromaleic acid, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, fluoromaleate.
• Examples include maleic acid monoesters such as alkyl.
• Examples of the acid anhydride of the dicarboxylic acid include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
• an acid anhydride that produces a carboxylic acid group by hydrolysis can also be used as the carboxylic acid group-containing monomer.
• sulfonic acid group-containing monomer examples include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, and (meth) acrylic. Acids include ethyl-2-sulfonate, 2-acrylamide-2-methylpropanesulfonic acid, and 3-allyloxy-2-hydroxypropanesulfonic acid.
• “(meth) allyl” means allyl and / or metallyl.
• examples of the phosphoric acid group-containing monomer capable of forming a phosphoric acid group-containing monomer unit include -2- (meth) acryloyloxyethyl phosphate and methyl-2- (meth) acryloyloxyethyl phosphate. , Ethyl phosphate- (meth) acryloyloxyethyl.
• "(meth) acryloyl” means acryloyl and / or methacryloyl.
• the acid group-containing monomer described above one type may be used alone, or two or more types may be used in combination.
• the acid group-containing monomer capable of forming the acid group-containing monomer unit is a carboxylic acid from the viewpoint of improving the adhesion between the heat-resistant layer and the base material and further improving the coatability of the slurry composition. Acid group-containing monomers are preferred, monocarboxylic acids are more preferred, and acrylic acids are even more preferred.
• the water-soluble polymer used in the present invention has an acid group-containing monomer unit content of 1 when the amount of all repeating units (all monomer units) in the water-soluble polymer is 100% by mass. It is necessary to be by mass% or more and 20% by mass or less, preferably 2% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and 7% by mass. The above is particularly preferable, 16% by mass or less is preferable, 12% by mass or less is more preferable, and 10% by mass or less is further preferable. When the content ratio of the acid group-containing monomer unit in the water-soluble polymer is less than 1% by mass, the coatability of the slurry composition is lowered.
• the adsorption force of the water-soluble polymer to the non-conductive inorganic particles is reduced, it is not possible to sufficiently secure the adhesion between the heat-resistant layer and the base material.
• the content ratio of the acid group-containing monomer unit in the water-soluble polymer is more than 20% by mass, the dispersion stability of the slurry composition is lowered.
• Hydroxy group-containing monomer unit Examples of the hydroxyl group-containing monomer capable of forming a hydroxyl group-containing monomer unit include N-hydroxymethyl acrylamide, N-hydroxyethyl acrylamide, N-hydroxypropyl acrylamide, N-hydroxymethyl methacrylate, and N-hydroxy.
• Hydroxy group-containing (meth) acrylamide monomers such as ethylmethacrylate and N-hydroxypropylmethacrylate; 2-hydroxymethylacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxy Hydroxy group-containing (meth) acrylate monomers such as methyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate; and the like.
• a hydroxyl group is contained (meth).
• Acrylamide monomer is preferable, and N-hydroxyethyl acrylamide and N-hydroxymethyl acrylamide are more preferable.
• the hydroxy group-containing monomer may be used alone or in combination of two or more.
• (meth) acrylate means acrylate and / or methacrylate.
• the water-soluble polymer contained in the binder composition of the present invention needs to contain a hydroxyl group-containing monomer unit. If the water-soluble polymer does not contain a hydroxyl group-containing monomer unit, the dispersion stability and coatability of the slurry composition are lowered.
• the content ratio of the hydroxyl group-containing monomer unit in the water-soluble polymer is 1% by mass or more when the amount of all repeating units (all monomer units) in the water-soluble polymer is 100% by mass. It is preferably 3% by mass or more, more preferably 4% by mass or more, particularly preferably 10% by mass or more, and preferably 25% by mass or less, 21% by mass.
• the content ratio of the hydroxyl group-containing monomer unit in the water-soluble polymer is 1% by mass or more, the dispersion stability and coatability of the slurry composition can be further improved.
• the content ratio of the hydroxyl group-containing monomer unit in the water-soluble polymer is 25% by mass or less, the heat-resistant shrinkage of the heat-resistant layer can be further enhanced.
• the other repeating units contained in the water-soluble polymer are not particularly limited.
• the water-soluble polymer may contain one kind of other repeating units, or may contain two or more kinds.
• the content ratio of the other repeating units is preferably 10% by mass or less, and 5% by mass. It is more preferably less than or equal to, more preferably 1% by mass or less, and particularly preferably 0% by mass.
• the molar ratio (hydroxyl group / acid group molar ratio) of the content ratio of the hydroxyl group-containing monomer unit to the content ratio of the acid group-containing monomer unit in the water-soluble polymer is 0.70 or more. It is preferably 0.80 or more, more preferably 0.90 or more, and particularly preferably 1.00 or more.
• the molar ratio of hydroxyl group / acid group is 0.70 or more, the dispersion stability and coatability of the slurry composition can be further improved.
• the upper limit of the molar ratio of hydroxyl group / acid group is not particularly limited, but can be, for example, 5.00 or less, 3.00 or less, or 2.63 or less.
• the water-soluble polymer used in the present invention preferably has a weight average molecular weight of 200,000 or more, more preferably 300,000 or more, and further preferably 400,000 or more. It is particularly preferably 500,000 or more, preferably 2,000,000 or less, more preferably 1,500,000 or less, still more preferably 1,000,000 or less.
• the weight average molecular weight of the water-soluble polymer is 200,000 or more, the rigidity of the water-soluble polymer is improved, so that the heat-resistant shrinkage of the heat-resistant layer can be further enhanced.
• the weight average molecular weight of the water-soluble polymer is 2,000,000 or less, the viscosity of the slurry composition is lowered, so that the coatability of the slurry composition can be further improved.
• the weight average molecular weight of the water-soluble polymer can be adjusted, for example, by changing the type and amount of the polymerization initiator and / or the polymerization accelerator used in the preparation of the water-soluble polymer.
• the non-conductive inorganic particles are used in the slurry composition prepared by using the binder composition.
• the proportion of the water-soluble polymer adsorbed on the particles can be satisfactorily controlled.
• the dispersion stability and coatability of the slurry composition and the adhesion between the heat-resistant layer and the base material are sufficiently improved. Will be done.
• the proportion of the water-soluble polymer adsorbed on the non-conductive inorganic particles is determined by the slurry.
• the total water-soluble polymer in the composition is 100% by mass, it is preferably 10% by mass or more and 60% by mass or less.
• the non-conductive inorganic particles adsorbed by the water-soluble polymer are precipitated and precipitated.
• a method of calculating the weight loss behavior of a product during heating by using Tg / DTA, or a method of calculating the concentration of a water-soluble polymer in the supernatant after centrifuging the slurry composition. Can be mentioned.
• the above-mentioned water-soluble polymer is not particularly limited, and can be prepared by any method such as a solution polymerization method, a suspension polymerization method, a massive polymerization method, and an emulsion polymerization method. Further, as the polymerization method, addition polymerization such as ionic polymerization, radical polymerization and living radical polymerization can be used. As the polymerization initiator, polymerization accelerator, emulsifier, dispersant, chain transfer agent and the like used at the time of polymerization, commonly used ones can be used, and the amount used is also the amount generally used. Above all, an aqueous solution polymerization method using water as a polymerization solvent is preferable because it does not require a solvent removal operation, the solvent is highly safe, and there is no problem of mixing of a surfactant.
• the pH of the aqueous solution is adjusted to 7 or more and 9 or less after the polymerization. Is preferable. This is because if the obtained aqueous solution is neutralized and the pH is adjusted to the above range, the viscosity stability of the slurry composition can be easily improved.
• examples of the polymerization initiator that can be used for preparing the water-soluble polymer include, without particular limitation, known polymerization initiators such as sodium persulfate, ammonium persulfate, and potassium persulfate. Above all, it is preferable to use ammonium persulfate.
• the polymerization initiator one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.
• the polymerization accelerator is not particularly limited, and known reducing polymerization accelerators such as L-ascorbic acid, sodium bisulfite, and tetramethylethylenediamine can be used. Above all, it is preferable to use L-ascorbic acid.
• L-ascorbic acid As the polymerization accelerator, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.
• the particulate polymer that can be optionally contained in the binder composition of the present invention is a component that functions as a binder, like the water-soluble polymer described above.
• the binder composition contains a particulate polymer, the adhesion between the obtained heat-resistant layer and the base material can be improved.
• the particulate polymer is a water-insoluble particle formed by a predetermined polymer.
• water-insoluble means that when 0.5 g of the polymer is dissolved in 100 g of water at a temperature of 25 ° C., the insoluble content is 90% by mass or more.
• the particulate polymer is not particularly limited as long as it is water-insoluble and can be dispersed in a dispersion medium such as water, but for example, a conjugated diene polymer, a fluorine polymer, and the like.
• Acrylic polymers can be used. And among these, it is preferable to use an acrylic polymer.
• an acrylic polymer is used as the particulate polymer contained in the binder composition, the adhesion between the heat-resistant layer and the base material can be improved, and the oxidation resistance of the battery member provided with the heat-resistant layer can be improved.
• the particulate polymer one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.
• the conjugated diene-based polymer is a polymer containing a conjugated diene monomer unit.
• Specific examples of the conjugated diene-based polymer are not particularly limited, and include an aromatic vinyl monomer unit such as a styrene-butadiene copolymer (SBR) and an aliphatic conjugated diene monomer unit. Examples include polymers, butadiene rubber (BR), isoprene rubber, acrylic rubber (NBR) (polymers containing acrylonitrile units and butadiene units), and hydrides thereof.
• SBR styrene-butadiene copolymer
• NBR acrylic rubber
• Fluorine-based polymer examples include, but are not limited to, polyvinylidene fluoride (PVdF), polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) copolymer, and the like.
• PVdF polyvinylidene fluoride
• PVdF-HFP polyvinylidene fluoride-hexafluoropropylene
• the acrylic polymer is a polymer containing a (meth) acrylic acid ester monomer unit. Further, the acrylic polymer may contain a repeating unit other than the (meth) acrylic acid ester monomer unit.
• the repeating unit is not particularly limited, and a hydrophilic group-containing monomer unit and a crosslinkable monomer unit are preferably used. However, a (meth) acrylic acid ester monomer unit and a hydrophilic group-containing unit are used.
• Monomer units (other monomer units) other than the body unit and the crosslinkable monomer unit can also be mentioned.
• Examples of the (meth) acrylic acid ester monomer capable of forming a (meth) acrylic acid ester monomer unit include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, and t-butyl acrylate.
• Acrylic acid alkyl esters such as ⁇ , pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, pentyl.
• Alkyl methacrylate esters such as methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, and 2-ethylhexyl methacrylate; and the like.
• the content ratio of the (meth) acrylic acid ester monomer unit in the particulate polymer is 50 when the amount of all repeating units (all monomer units) in the particulate polymer is 100% by mass. It is preferably more than mass%, more preferably 60% by mass or more, preferably 99% by mass or less, and more preferably 97% by mass or less.
• hydrophilic group-containing monomer unit examples include the "acid group-containing monomer” and the "hydroxyl group-containing monomer” described in the section of "water-soluble polymer”. Can be mentioned. One of these may be used alone, or two or more of them may be used in combination. Among these, it is preferable to use methacrylic acid as the hydrophilic group-containing monomer.
• the content ratio of the hydrophilic group-containing monomer unit in the particulate polymer is 1% by mass when the amount of all repeating units (all monomer units) in the particulate polymer is 100% by mass. It is preferably more than that, and preferably 5% by mass or less.
• Crosslinkable monomer unit examples include glycidyl methacrylate, allyl glycidyl ether, ethylene glycol dimethacrylate, allyl (meth) acrylate, and divinylbenzene. One of these may be used alone, or two or more of them may be used in combination. Among these, it is preferable to use allyl glycidyl ether or allyl methacrylate as the crosslinkable monomer.
• the content ratio of the crosslinkable monomer unit in the particulate polymer is 1% by mass or more when the amount of all repeating units (all monomer units) in the particulate polymer is 100% by mass. It is preferably 5% by mass or less.
• Examples of the other monomer capable of forming other monomer units include monomers other than the above-mentioned (meth) acrylic acid ester monomer, hydrophilic group-containing monomer and crosslinkable monomer.
• other monomers include ⁇ , ⁇ -unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; styrene, chlorostyrene, vinyltoluene, t-butylstyrene, methyl vinylbenzoate, and vinyl.
• examples thereof include styrene-based monomers such as naphthalene, chloromethylstyrene, and ⁇ -methylstyrene.
• the content ratio of other monomer units in the particulate polymer is 1% by mass or more when the amount of all repeating units (all monomer units) in the particulate polymer is 100% by mass. It is preferable that it is 35% by mass or less.
• the glass transition temperature of the particulate polymer is preferably less than 20 ° C, more preferably less than 15 ° C.
• the adhesion between the heat-resistant layer and the base material can be improved.
• the lower limit of the glass transition temperature of the particulate polymer is not particularly limited, but can be, for example, more than ⁇ 120 ° C. and more than ⁇ 60 ° C.
• the "glass transition temperature" of the particulate polymer can be measured by using the method described in the examples of the present specification.
• the glass transition temperature of the particulate polymer can be adjusted, for example, by changing the type and amount of the monomer, polymerization initiator and / or polymerization accelerator used in the preparation of the particulate polymer. ..
• the volume average particle size of the particulate polymer is preferably 0.1 ⁇ m or more, more preferably 0.15 ⁇ m or more, further preferably 0.2 ⁇ m or more, and 0.31 ⁇ m or more. It is particularly preferable that it is 1 ⁇ m or less, more preferably 0.8 ⁇ m or less, and further preferably 0.5 ⁇ m or less.
• the volume average particle diameter of the particulate polymer is 0.1 ⁇ m or more, the cycle characteristics of the secondary battery can be improved.
• the volume average particle diameter of the particulate polymer is 1 ⁇ m or less, the adhesion between the heat-resistant layer and the base material can be improved.
• the "volume average particle size” means "a particle size (D50) in which the cumulative volume calculated from the small diameter side in the particle size distribution (volume basis) measured by the laser diffraction method is 50%".
• the volume average particle size of the particulate polymer can be adjusted, for example, by changing the type and amount of the monomer, polymerization initiator and / or polymerization accelerator used in the preparation of the particulate polymer. it can.
• the polymerization method of the particulate polymer is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a massive polymerization method, and an emulsion polymerization method may be used.
• addition polymerization such as ionic polymerization, radical polymerization and living radical polymerization can be used.
• the polymerization solvent, emulsifier, dispersant, polymerization initiator, chain transfer agent, etc. that can be used for polymerization, general ones can be used, and the amount used may also be a generally used amount. it can.
• the content ratio of the water-soluble polymer to the particulate polymer in the binder composition of the present invention is not particularly limited, but the water-soluble polymer accounts for the total content of the water-soluble polymer and the particulate polymer. Is preferably 15% by mass or more, more preferably 25% by mass or more, further preferably 30% by mass or more, preferably 70% by mass or less, and 60% by mass or less. It is more preferable that it is 50% by mass or less.
• the heat-resistant shrinkage of the heat-resistant layer can be further improved, and it may be 70% by mass or less.
• the adhesion between the heat-resistant layer and the base material can be improved.
• the dispersion medium of the binder composition of the present invention is not particularly limited as long as it contains water.
• the binder composition of the present invention may contain only water as the dispersion medium, or the dispersion medium may be a mixture of water and an organic solvent (for example, esters, ketones, alcohols).
• the binder composition of the present invention may contain one kind of organic solvent, or may contain two or more kinds of organic solvents.
• the binder composition of the present invention includes a reinforcing material, a leveling agent, a wetting agent, a dispersant, a viscosity modifier, an electrolyte additive, a preservative, a fungicide, an antifoaming agent, and a polymerization inhibitor.
• a binder other than the water-soluble polymer and the particulate polymer of the present invention may be contained. These are not particularly limited as long as they do not affect the battery reaction, and known ones can be used.
• one type of other components may be used alone, or two or more types may be used in combination at an arbitrary ratio.
• the wetting agent is not particularly limited, and an ethylene oxide / propylene oxide-based surfactant (EO / PO-based surfactant), a fluorine-based surfactant, a silicon-based surfactant, or the like can be used. it can. Among them, it is preferable to use an EO / PO-based surfactant and a fluorine-based surfactant, and it is more preferable to use an EO / PO-based surfactant.
• the dispersant is not particularly limited, and is not particularly limited, and is a polycarboxylic acid such as polyacrylic acid, sodium polycarboxylic acid such as sodium polyacrylate, ammonium polycarboxylic acid such as ammonium polyacrylate, and sulfonic acid polycarboxylic acid.
• Copolymers, sodium polycarboxylic acid sulfonic acid copolymer, ammonium polycarboxylic acid sulfonic acid copolymer and the like can be used. Above all, it is preferable to use sodium polyacrylate.
• Specific examples of the above-mentioned other components other than the wetting agent and the dispersant are not particularly limited, and examples thereof include those described in International Publication No. 2012/115096.
• the binder composition of the present invention can be prepared by mixing the above-mentioned water-soluble polymer and water, and any particulate polymer and other components by a known method.
• the binder composition is obtained by mixing each of the above components using a mixer such as a ball mill, a sand mill, a bead mill, a pigment disperser, a grinder, an ultrasonic disperser, a homogenizer, a planetary mixer, and a fill mix. Things can be prepared.
• the water-soluble polymer and any particulate polymer are prepared by polymerizing in an aqueous solvent, they are mixed as they are in the state of an aqueous solution or an aqueous dispersion to prepare a binder composition containing water as a solvent. can do. Further, for example, the binder composition and the slurry composition described later are prepared at the same time, for example, by mixing the water-soluble polymer and the non-conductive inorganic particles and then adding an arbitrary particulate polymer. You may.
• the slurry composition of the present invention is a composition used for forming a heat-resistant layer, includes non-conductive inorganic particles and the above-mentioned binder composition, and optionally further contains other components. That is, the slurry composition of the present invention usually contains non-conductive inorganic particles, a water-soluble polymer and water as a dispersion medium, and optionally further contains a particulate polymer and other components. Since the slurry composition of the present invention contains the above-mentioned binder composition, it is excellent in dispersion stability and coatability, and by drying the slurry composition of the present invention on a substrate, heat shrinkage is achieved. A heat-resistant layer having excellent properties can be obtained.
• non-conductive inorganic particles contained in the slurry composition for a heat-resistant layer are particularly limited as long as they are particles made of an inorganic material that exists stably in the usage environment of the secondary battery and is electrochemically stable. Not done. From this point of view, preferred examples of non-conductive inorganic particles include aluminum oxide (alumina, Al 2 O 3 ), aluminum oxide hydrate (bemite, Al OOH), gibsite (Al (OH) 3 ), and oxidation.
• Inorganic oxide particles such as silicon, magnesium oxide (magnesia), magnesium hydroxide, calcium oxide, titanium oxide (titania), barium titanate (BaTIO 3 ), ZrO, alumina-silica composite oxide; aluminum nitride, boron nitride, etc.
• Nitride particles covalently bonded crystal particles such as silicon and diamond; sparingly soluble ion crystal particles such as barium sulfate, calcium fluoride and barium fluoride; clay fine particles such as talc and montmorillonite; and the like.
• the non-conductive inorganic particles include particles made of alumina (alumina particles). , Boehmite particles (boehmite particles) and barium sulfate particles (barium sulfate particles) are preferable, and alumina particles and barium sulfate particles are more preferable.
• these particles may be subjected to element substitution, surface treatment, solid solution formation, etc., if necessary.
• one type of these particles may be used alone, or two or more types may be used in combination.
• the binder composition As the binder composition, the above-mentioned binder composition of the present invention containing a water-soluble polymer and water, and any particulate polymer and other components is used.
• the content of the above-mentioned predetermined water-soluble polymer in the slurry composition is 0.5 in terms of solid content per 100 parts by mass of the non-conductive inorganic particles from the viewpoint of further enhancing the heat-resistant shrinkage of the heat-resistant layer. It is preferably parts by mass or more, and more preferably parts by mass or more.
• the content of the water-soluble polymer in the slurry composition shall be 5 parts by mass or less in terms of solid content per 100 parts by mass of the non-conductive inorganic particles from the viewpoint of improving the cycle characteristics of the secondary battery. Is preferable, and the amount is more preferably 3 parts by mass or less.
• the content of the above-mentioned particulate polymer in the slurry composition is 1 part by mass in terms of solid content per 100 parts by mass of the non-conductive inorganic particles from the viewpoint of improving the adhesion between the heat-resistant layer and the base material. The above is preferable, 1.2 parts by mass or more is more preferable, and 1.4 parts by mass or more is further preferable.
• the content of the particulate polymer in the slurry composition shall be 20 parts by mass or less in terms of solid content per 100 parts by mass of the non-conductive inorganic particles from the viewpoint of improving the cycle characteristics of the secondary battery. Is more preferable, and it is more preferably 10 parts by mass or less, and further preferably 7 parts by mass or less.
• Other components that can be blended in the slurry composition include, without particular limitation, the same components as those that can be blended in the binder composition of the present invention.
• one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.
• the content of the above-mentioned wetting agent in the slurry composition is preferably 0.01 part by mass or more, and more preferably 0.05 part by mass or more per 100 parts by mass of the non-conductive inorganic particles. It is more preferably 0.1 part by mass or more, preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and further preferably 1 part by mass or less.
• the content of the wetting agent is 0.01 parts by mass or more per 100 parts by mass of the non-conductive inorganic particles, the wettability to the substrate is improved and the generation of repellency is suppressed, so that the slurry composition is coated. The sex can be further enhanced. Further, if the content of the wetting agent is 5 parts by mass or less per 100 parts by mass of the non-conductive inorganic particles, the cycle characteristics of the secondary battery can be improved.
• the content of the above-mentioned dispersant in the slurry composition is preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more, per 100 parts by mass of the non-conductive inorganic particles.
• the content of the dispersant is 0.1 parts by mass or more per 100 parts by mass of the non-conductive inorganic particles, the dispersion stability of the slurry composition can be further improved and the heat shrinkage of the heat-resistant layer can be further improved. .. Further, when the content of the dispersant is 5 parts by mass or less per 100 parts by mass of the non-conductive inorganic particles, the amount of water remaining in the heat-resistant layer formed by using the slurry composition is reduced, and the secondary battery is used. Cycle characteristics can be improved.
• the above-mentioned slurry composition can be prepared by mixing each of the above-mentioned components by a known mixing method. Such mixing can be performed using, for example, a mixer such as a ball mill, a sand mill, a bead mill, a pigment disperser, a grinder, an ultrasonic disperser, a homogenizer, a planetary mixer, or a fill mix.
• a mixer such as a ball mill, a sand mill, a bead mill, a pigment disperser, a grinder, an ultrasonic disperser, a homogenizer, a planetary mixer, or a fill mix.
• the heat-resistant layer of the present invention is formed from the above-mentioned slurry composition of the present invention.
• the above-mentioned slurry composition is applied to the surface of an appropriate base material to form a coating film, and then formed. It can be formed by drying the coating film.
• the heat-resistant layer of the present invention comprises a dried product of the above-mentioned slurry composition, and usually contains at least non-conductive inorganic particles and a water-soluble polymer. Since each component contained in the heat-resistant layer was contained in the above slurry composition, a suitable abundance ratio of each component is a suitable presence of each component in the slurry composition. It is the same as the ratio. Since the heat-resistant layer of the present invention is formed from the slurry composition of the present invention containing the binder composition of the present invention, it is excellent in heat-resistant shrinkage.
• ⁇ Base material> there is no limitation on the base material to which the slurry composition is applied.
• a coating film of the slurry composition is formed on the surface of the release base material, and the coating film is dried to form a heat-resistant layer.
• the release base material may be peeled off from the mold.
• the heat-resistant layer peeled off from the release base material can be used as a self-supporting film for forming the battery member of the secondary battery.
• the separator base material is not particularly limited, and examples thereof include known separator base materials such as an organic separator base material.
• the organic separator base material is a porous member made of an organic material, and examples of the organic separator base material include polyolefin resins such as polyethylene and polypropylene, microporous membranes containing aromatic polyamide resins, and non-woven fabrics.
• a microporous film made of polyethylene or a non-woven fabric is preferable because of its excellent strength.
• Electrode base material is not particularly limited, and examples thereof include an electrode base material in which an electrode mixture layer containing an electrode active material and a binder is formed on a current collector. Electrode active material (positive electrode active material, negative electrode active material) and binder for electrode mixture layer (bonding material for positive electrode mixture layer, binder for negative electrode mixture layer) in the current collector and electrode mixture layer , And a known method for forming the electrode mixture layer on the current collector can be used, and examples thereof include those described in Japanese Patent Application Laid-Open No. 2013-145763.
• Examples of the method for forming the heat-resistant layer on the substrate such as the separator substrate and the electrode substrate described above include the following methods. 1) A method in which the slurry composition of the present invention is applied to the surface of a base material (in the case of an electrode base material, the surface on the electrode mixture layer side, the same applies hereinafter), and then dried; 2) A method of immersing a base material in the slurry composition of the present invention and then drying it; and 3) applying the slurry composition of the present invention on a release base material and drying to produce a heat-resistant layer. A method of transferring the heat-resistant layer to the surface of a base material.
• the method 1) is particularly preferable because it is easy to control the layer thickness of the heat-resistant layer.
• the method 1) is specifically a step of applying the slurry composition on the base material (coating step) and a step of drying the slurry composition applied on the base material to form a heat-resistant layer (drying). Step) is included.
• the method of coating the slurry composition on the substrate is not particularly limited, and for example, a doctor blade method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating method and the like. Method can be mentioned.
• the method for drying the slurry composition on the substrate is not particularly limited, and a known method can be used. Examples of the drying method include drying with warm air, hot air, low humidity air, vacuum drying, and drying with irradiation with infrared rays or electron beams.
• the secondary battery of the present invention includes the heat-resistant layer of the present invention described above. More specifically, the secondary battery of the present invention includes a positive electrode, a negative electrode, a separator, and an electrolytic solution, and the heat-resistant layer described above is included in at least one of the positive electrode, the negative electrode, and the separator, which are battery members.
• At least one of the positive electrode, the negative electrode, and the separator used in the secondary battery of the present invention is a battery member including the heat-resistant layer of the present invention described above.
• the positive electrode, negative electrode and separator without the heat-resistant layer of the present invention are not particularly limited, and known positive electrodes, negative electrodes and separators can be used.
• an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is usually used.
• a lithium salt is used in a lithium ion secondary battery.
• the lithium salt 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 preferable because they are easily soluble in a solvent and show a high degree of dissociation.
• One type of electrolyte may be used alone, or two or more types may be used in combination. Normally, the more the supporting electrolyte with a higher degree of dissociation is used, the higher the lithium ion conductivity tends to be. Therefore, the lithium ion conductivity can be adjusted depending on the type of the supporting electrolyte.
• the organic solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte.
• a mixed solution of these solvents may be used.
• carbonates are preferable because they have a high dielectric constant and a wide stable potential region.
• the concentration of the electrolyte in the electrolytic solution can be adjusted as appropriate. Further, a known additive may be added to the electrolytic solution.
• a positive electrode and a negative electrode are overlapped with each other via a separator, and if necessary, the positive electrode and the negative electrode are placed in a battery container by winding or folding according to the battery shape, and the battery container is used. It can be manufactured by injecting an electrolytic solution into the battery and sealing the container.
• At least one member of the positive electrode, the negative electrode, and the separator is a member with a heat resistant layer.
• an overcurrent prevention element such as a fuse and a PTC element, an expanded metal, a lead plate, and the like may be provided, if necessary.
• the shape of the secondary battery may be, for example, a coin type, a button type, a sheet type, a cylindrical type, a square type, a flat type, or the like.
• the present invention will be specifically described based on examples, but the present invention is not limited to these examples.
• “%” and “part” representing quantities are based on mass unless otherwise specified.
• the ratio of the monomer unit formed by polymerizing a certain monomer to the polymer is usually specified unless otherwise specified. It is consistent with the ratio (preparation ratio) of the certain monomer to all the monomers used for the polymerization of the polymer.
• the weight average molecular weight of the water-soluble polymer, the glass transition temperature and volume average particle diameter of the particulate polymer, the dispersion stability and coatability of the slurry composition for a heat-resistant layer, and the heat-resistant layer The heat-resistant shrinkage, the adhesion between the heat-resistant layer and the base material, and the cycle characteristics of the secondary battery were evaluated by the following methods.
• ⁇ Weight average molecular weight of water-soluble polymer> The aqueous solution containing the water-soluble polymer prepared in Examples and Comparative Examples was diluted to adjust the concentration to 0.5%. Next, caustic soda was added until the pH reached 10 to 12, soaked in a hot water bath at 80 ° C.
• Detector Differential refractive index detector RI (manufactured by Showa Denko KK, product name "RI-201", sensitivity 32)
• Injection volume 0.2 mL
• Standard sample Monodisperse polyethylene oxide (PEO), polyethylene glycol (PEG) manufactured by Tosoh Corporation and Sigma-Aldrich LLC.
• ⁇ Glass transition temperature of particulate polymer> A powdery sample obtained by drying an aqueous dispersion containing a particulate polymer at a temperature of 25 ° C. for 48 hours was used as a measurement sample. Weigh 10 mg of the measurement sample into an aluminum pan and raise the temperature in the measurement temperature range of -100 ° C to 200 ° C with a differential thermal analysis measuring device (manufactured by SII Nanotechnology Co., Ltd., product name "EXSTAR DSC6220"). Measurements were performed at a rate of 20 ° C./min under the conditions specified in JIS Z8703 to obtain a differential scanning calorimetry (DSC) curve. An empty aluminum pan was used as a reference.
• DSC differential scanning calorimetry
• the temperature at which the differential signal (DDSC) peaks was determined as the glass transition temperature (° C.). Since a plurality of peaks were measured, the temperature showing the peak with a large displacement was defined as the glass transition temperature of the particulate polymer.
• DDSC differential signal
• the volume average particle size of the particulate polymer was measured by a laser diffraction method. Specifically, an aqueous dispersion containing the prepared particulate polymer (adjusted to a solid content concentration of 0.1% by mass) was used as a sample.
• the slurry composition for a heat-resistant layer in a plastic bottle was sampled from within 1 cm above the top, and then the solid content concentration of the sampled supernatant was measured. After stirring, the slurry composition in the plastic bottle was extracted, and then the presence or absence of sticking to the bottom of the plastic bottle was confirmed and evaluated as follows.
• B The solid content concentration of the supernatant after stirring is 39.5% or more, but sticking to the bottom of the plastic bottle is observed.
• C The solid content concentration of the supernatant after stirring is less than 39.5%.
• ⁇ Coatability of slurry composition for heat-resistant layer The appearance of the heat-resistant layer formed from the slurry composition for the heat-resistant layer prepared in Examples and Comparative Examples was visually observed and evaluated as follows.
• C The area where no agglomerates, streaks, and / or repellents are seen is less than 10 cm ⁇ 10 cm.
• the separator with a heat-resistant layer produced in Examples and Comparative Examples was cut into a width of 10 mm and a length of 50 mm to prepare a test piece.
• a SUS plate to which a double-sided tape (Nitto Denko KK, No. 5608) was attached was prepared, and the surface of the heat-resistant layer of the test piece was attached to the double-sided tape.
• Capacity retention rate ⁇ C (C1 / C0) ⁇ 100 (%) was calculated and evaluated according to the following criteria. The higher the value of the capacity retention rate, the less the decrease in the discharge capacity and the better the cycle characteristics.
• Example 1 ⁇ Preparation of aqueous solution containing water-soluble polymer> 6335 g of ion-exchanged water and 190 g of a 2.0% aqueous solution of L-ascorbic acid as a polymerization accelerator are put into a 10 L flask with a septum, heated to a temperature of 40 ° C., and a flask with a flow rate of 100 mL / min of nitrogen gas. Replaced inside. Next, 939.8 g (74.0%) of acrylamide as an amide group-containing monomer, 127.0 g (10.0%) of acrylic acid as an acid group-containing monomer, and a hydroxyl group-containing monomer.
• a monomer composition is obtained by mixing 2 parts of methacrylic acid as a body, 0.3 parts of allyl methacrylate as a crosslinkable monomer, 1.5 parts of allyl glycidyl ether, and 2 parts of acrylonitrile as other monomers.
• Got This monomer composition was continuously added to the above reactor over 4 hours to carry out polymerization. During the addition, the reaction was carried out at 60 ° C.
• the heat-resistant layer slurry composition contains a heat-resistant layer binder composition. That is, in this example, the slurry composition for the heat-resistant layer and the binder composition for the heat-resistant layer were prepared at the same time. The dispersion stability and coatability of the slurry composition for a heat-resistant layer thus obtained were evaluated. The results are shown in Table 1.
• a polyethylene separator base material manufactured by Asahi Kasei Corporation, product name "ND412", thickness: 12 ⁇ m
• the slurry composition for heat-resistant layer prepared above is applied to the surface of the prepared separator base material, dried at a temperature of 50 ° C. for 3 minutes, and a separator having a heat-resistant layer on one side (thickness of heat-resistant layer: 2.5 ⁇ m).
• the heat-resistant shrinkage of the heat-resistant layer thus obtained and the adhesion between the heat-resistant layer and the separator base material were evaluated. The results are shown in Table 1.
• the mixture was cooled to stop the polymerization reaction to obtain a mixture containing a particulate binder (styrene-butadiene copolymer).
• a particulate binder styrene-butadiene copolymer
• pH 8
• a 5% aqueous sodium hydroxide solution unreacted monomers were removed by hot vacuum distillation.
• the mixture was cooled to 30 ° C. or lower to obtain an aqueous dispersion containing a binder for the negative electrode.
• a slurry composition for the negative electrode mixture layer was prepared.
• the above slurry composition for the negative electrode mixture layer was applied to the surface of a copper foil having a thickness of 15 ⁇ m, which is a current collector, with a comma coater so that the amount of application was 11 ⁇ 0.5 mg / cm 2 .
• the copper foil coated with the slurry composition for the negative electrode mixture layer is conveyed at a rate of 400 mm / min in an oven at a temperature of 80 ° C.
• the slurry composition on the copper foil was dried to obtain a negative electrode raw fabric in which a negative electrode mixture layer was formed on the current collector. Then, the negative electrode mixture layer side of the prepared negative electrode raw material was roll-pressed under the condition of a linear pressure of 11 t (ton) in an environment of a temperature of 25 ⁇ 3 ° C., and a negative electrode having a negative electrode mixture layer density of 1.60 g / cm 3 Got Then, the negative electrode was left for one week in an environment of a temperature of 25 ⁇ 3 ° C. and a relative humidity of 50 ⁇ 5%.
• black manufactured by Denka Co., Ltd., product name "HS-100
• polyvinylidene fluoride manufactured by Kureha Chemical Co., Ltd., product name "KF-1100
• NMP N-methyl-2-pyrrolidone
• a dispersion medium was added and mixed so as to have a total solid content concentration of 67% to prepare a slurry composition for a positive electrode mixture layer.
• NMP N-methyl-2-pyrrolidone
• the obtained slurry composition for the positive electrode mixture layer was applied on an aluminum foil having a thickness of 20 ⁇ m, which is a current collector, with a comma coater so that the coating amount was 20 ⁇ 0.5 mg / cm 2. It was applied.
• the slurry composition on the aluminum foil is dried by transporting the slurry composition on the aluminum foil at a speed of 200 mm / min for 2 minutes in an oven having a temperature of 90 ° C.
• a positive electrode original fabric having a positive electrode mixture layer formed on it was obtained. Then, the positive electrode mixture layer side of the produced positive electrode raw material was roll-pressed under the condition of a linear pressure of 14 t (ton) in an environment of a temperature of 25 ⁇ 3 ° C., and a positive electrode having a positive electrode mixture layer density of 3.40 g / cm 3 Got Then, the positive electrode was left for one week in an environment of a temperature of 25 ⁇ 3 ° C. and a relative humidity of 50 ⁇ 5%.
• Example 2 When preparing an aqueous solution containing a water-soluble polymer, the amount of acrylamide as an amide group-containing monomer was 889.0 g (70.0%), and the amount of acrylic acid as an acid group-containing monomer was 152.4 g (152.4 g). 12.0%), the water-soluble polymer was prepared in the same manner as in Example 1 except that the amount of N-hydroxyethyl acrylamide as the hydroxyl group-containing monomer was changed to 228.6 g (18.0%).
• Example 3 When preparing an aqueous solution containing a water-soluble polymer, the amount of acrylamide as an amide group-containing monomer was 825.5 g (65.0%), and the amount of acrylic acid as an acid group-containing monomer was 139.7 g (139.7 g). 11.0%), the water-soluble polymer was prepared in the same manner as in Example 1 except that the amount of N-hydroxyethyl acrylamide as the hydroxyl group-containing monomer was changed to 304.8 g (24.0%).
• aqueous solution containing an aqueous solution, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 4 When preparing an aqueous solution containing a water-soluble polymer, the amount of acrylamide as an amide group-containing monomer was 825.5 g (65.0%), and the amount of acrylic acid as an acid group-containing monomer was 38.1 g (38.1 g). 3.0%), the water-soluble polymer was prepared in the same manner as in Example 1 except that the amount of N-hydroxyethyl acrylamide as the hydroxyl group-containing monomer was changed to 406.4 g (32.0%).
• aqueous solution containing an aqueous solution, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 5 When preparing an aqueous solution containing a water-soluble polymer, the amount of acrylamide as an amide group-containing monomer was 806.45 g (63.5%), and the amount of acrylic acid as an acid group-containing monomer was 215.9 g (215.9 g). 17.0%), the water-soluble polymer was prepared in the same manner as in Example 1 except that the amount of N-hydroxyethyl acrylamide as the hydroxyl group-containing monomer was changed to 247.65 g (19.5%).
• aqueous solution containing an aqueous solution, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 6 When preparing an aqueous solution containing a water-soluble polymer, the amount of acrylamide as an amide group-containing monomer was 1219.2 g (96.0%), and the amount of acrylic acid as an acid group-containing monomer was 17.78 g (. 1.4%), the water-soluble polymer was prepared in the same manner as in Example 1 except that the amount of N-hydroxyethyl acrylamide as the hydroxyl group-containing monomer was changed to 33.02 g (2.6%).
• aqueous solution containing an aqueous solution, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 7 When preparing an aqueous solution containing a water-soluble polymer, the amount of acrylamide as an amide group-containing monomer was 939.8 g (74.0%), and the amount of acrylic acid as an acid group-containing monomer was 203.2 g (203.2 g). 16.0%), the water-soluble polymer was prepared in the same manner as in Example 1 except that the amount of N-hydroxyethyl acrylamide as a hydroxyl group-containing monomer was changed to 127.0 g (10.0%).
• aqueous solution containing an aqueous solution, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 8 When preparing the aqueous solution containing the water-soluble polymer, the amount of acrylamide as the amide group-containing monomer was 939.8 g (74.0%), and the amount of acrylic acid as the acid group-containing monomer was 63.5 g (63.5 g). 5.0%), the water-soluble polymer was prepared in the same manner as in Example 1 except that the amount of N-hydroxyethyl acrylamide as the hydroxyl group-containing monomer was changed to 266.7 g (21.0%).
• aqueous solution containing an aqueous solution, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 9 An aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that an aqueous solution containing the water-soluble polymer prepared as follows is used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 10 An aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that an aqueous solution containing the water-soluble polymer prepared as follows is used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 11 An aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that an aqueous solution containing the water-soluble polymer prepared as follows is used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• aqueous solution containing water-soluble polymer 6335 g of ion-exchanged water and 66.5 g of a 2.0% aqueous solution of L-ascorbic acid as a polymerization accelerator are put into a 10 L flask with a septum, heated to a temperature of 40 ° C., and a flow rate of 100 mL / min nitrogen gas. The inside of the flask was replaced with.
• Example 12 When preparing an aqueous solution containing a water-soluble polymer, the amount of acrylamide as an amide group-containing monomer was 933.45 g (73.5%), and the amount of acrylic acid as an acid group-containing monomer was 120.65 g (20.65 g). 9.5%) and instead of 203.2 g (16.0%) of N-hydroxyethyl acrylamide as a hydroxyl group-containing monomer, 215.9 g (17.0%) of 2-hydroxyethyl methacrylate. It was used. Further, at the time of preparing the slurry composition for the heat-resistant layer, the amount of the aqueous dispersion containing the particulate polymer was changed to 3 parts in terms of solid content.
• an aqueous solution containing a water-soluble polymer, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery are prepared in the same manner as in Example 1. Or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 13 When preparing the aqueous solution containing the water-soluble polymer, 2-hydroxyethyl acrylate was used instead of N-hydroxyethyl acrylamide as the hydroxyl group-containing monomer. Further, at the time of preparing the slurry composition for the heat-resistant layer, the amount of the aqueous dispersion containing the particulate polymer was changed to 3 parts in terms of solid content.
• an aqueous solution containing a water-soluble polymer, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery are prepared in the same manner as in Example 1. Or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• Example 14 Same as in Example 1 except that the aqueous dispersion containing the particulate polymer was not added and the amount of the aqueous solution containing the water-soluble polymer was changed to 4 parts in terms of solid content when preparing the slurry composition for the heat-resistant layer. Then, an aqueous solution containing a water-soluble polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• Example 15 An aqueous solution containing a water-soluble polymer in the same manner as in Example 1 except that the amount of the aqueous dispersion containing the particulate polymer was changed to 1.3 parts in terms of solid content when preparing the slurry composition for the heat-resistant layer. , An aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• Example 16 An aqueous solution containing a water-soluble polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that the aqueous dispersion containing the particulate polymer prepared as follows was used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• an aqueous sodium hydroxide solution was added to adjust the pH to 8.0, and then steam was introduced to obtain unreacted monomers. Removed. Then, while adjusting the solid content concentration with ion-exchanged water, filtration is performed with a 200 mesh (opening: about 77 ⁇ m) stainless steel wire mesh to obtain an aqueous dispersion containing a particulate polymer (solid content concentration: 40%). Obtained.
• Example 17 An aqueous solution containing a water-soluble polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that the aqueous dispersion containing the particulate polymer prepared as follows was used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• This monomer composition was continuously added to the above reactor over 4 hours for polymerization. During the continuous addition, the reaction was carried out at 70 ° C. After the continuous addition was completed, the reaction was further completed with stirring at 80 ° C. for 3 hours to obtain an aqueous dispersion of the particulate polymer. After cooling the aqueous dispersion of the obtained particulate polymer to 25 ° C., an aqueous sodium hydroxide solution was added to adjust the pH to 8.0, and then steam was introduced to obtain unreacted monomers. Removed.
• Example 18 Barium sulfate particles (manufactured by Takehara Chemical Industry Co., Ltd., product name "TS-3", volume average particle diameter: 0.5 ⁇ m) instead of alumina particles as non-conductive inorganic particles when preparing a slurry composition for a heat-resistant layer.
• Aqueous solution containing a water-soluble polymer, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery in the same manner as in Example 1 except that Was prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that an aqueous solution containing the water-soluble polymer prepared as follows is used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2. ⁇ Preparation of aqueous solution containing water-soluble polymer> In a 10 L flask with a septum, 895.0 g (89.5%) of acrylamide as an amide group-containing monomer and 15.0 g (1.5%) of dimethylacrylamide, and 90.
• Acrylic acid as an acid group-containing monomer A monomer composition consisting of 0 g (9.0%), 3650 g of ion-exchanged water and 50 g of isopropyl alcohol were charged, and the inside of the flask was replaced with nitrogen gas at a flow rate of 100 mL / min. Then, under stirring, 70 g of a 5% ammonium persulfate aqueous solution and 30 g of a 5% sodium bisulfite aqueous solution as a polymerization initiator were put into a flask, and then the temperature was raised from room temperature to 80 ° C. and kept warm for 3 hours. Then, 1620 g of ion-exchanged water was added, and the pH was adjusted to 8 with a 10% aqueous sodium hydroxide solution to obtain an aqueous solution containing a water-soluble polymer.
• Example 3 An aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that an aqueous solution containing the water-soluble polymer prepared as follows is used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• Example 4 An aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, and a separator are the same as in Example 1 except that an aqueous solution containing the water-soluble polymer prepared as follows is used. And lithium ion secondary batteries were prepared or made. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• aqueous solution containing an aqueous solution, an aqueous dispersion containing a particulate polymer, a slurry composition for a heat-resistant layer, a negative electrode, a positive electrode, a separator, and a lithium ion secondary battery were prepared or prepared. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.
• AAm represents an acrylamide unit
• DMAAm represents a dimethylacrylamide unit
• MAAm represents a methacrylamide unit
• AA indicates an acrylic acid unit
• ATBS represents the 2-acrylamide-2-methylpropanesulfonic acid unit
• HEAAm represents the N-hydroxyethylacrylamide unit
• HEMA represents a 2-hydroxyethyl methacrylate unit
• HHA represents a 2-hydroxyethyl acrylate unit
• MAN indicates a methacrylonitrile unit
• BA represents an n-butyl acrylate unit
• 2EHA represents a 2-ethylhexyl acrylate unit
• MAA indicates a methacrylic acid unit
• AGE indicates an allyl glycidyl ether unit
• AMA indicates an allyl methacrylate unit
• AN indicates an acrylonitrile unit
• ST indicates a sty
• the amide group-containing monomer unit, the acid group-containing monomer unit, and the hydroxyl group-containing monomer unit are contained, and the amide group-containing monomer unit and the acid group-containing monomer unit are contained.
• a slurry composition having excellent dispersion stability and coatability and heat resistance having excellent heat shrinkage It can be seen that the layer can be formed. Further, it can be seen that the heat-resistant layers of Examples 1 to 18 have excellent adhesion to the base material and can exhibit excellent cycle characteristics in the secondary battery.
• Comparative Example 1 using a binder composition containing a water-soluble polymer composed of only an amide group-containing monomer unit and an acid group-containing monomer unit, the dispersion stability and coatability of the slurry composition were sufficiently sufficient. It turns out that it has not been secured. Further, in Comparative Example 2 using a binder composition containing a water-soluble polymer composed of only an amide group-containing monomer unit, the dispersion stability and coatability of the slurry composition could not be sufficiently ensured, and the base material was not sufficiently secured. It can be seen that the heat-resistant layer having excellent adhesion to the surface has not been formed.
• Comparative Example 3 using the binder composition containing the water-soluble polymer in which the content ratios of the amide group-containing monomer unit and the acid group-containing monomer unit were out of the predetermined ranges, the slurry composition was dispersed. It can be seen that the stability and coatability cannot be sufficiently ensured, and the heat-resistant layer having excellent heat-resistant shrinkage cannot be formed. Further, in Comparative Example 4 using a binder composition containing a water-soluble polymer in which the content ratios of the amide group-containing monomer unit and the acid group-containing monomer unit were out of the predetermined ranges, the slurry composition was dispersed.
• a slurry composition for a non-aqueous secondary battery heat-resistant layer capable of forming a heat-resistant layer for a non-aqueous secondary battery which is excellent in dispersion stability and coatability and also excellent in heat shrinkage.
• a binder composition for a heat-resistant layer of an aqueous secondary battery can be provided.
• a slurry composition for a non-aqueous secondary battery heat-resistant layer capable of forming a heat-resistant layer for a non-aqueous secondary battery having excellent dispersion stability and coatability and excellent heat-resistant shrinkage. can do.

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