Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • 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
• • 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
  • C08F220/22—Esters containing halogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/12—Powdering or granulating
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/42—Acrylic resins
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/426—Fluorocarbon polymers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/443—Particulate material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
• • 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
  • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• • 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 fluorine-containing polymer particles that can form coating films with excellent adhesive and adhesion suppression properties.
• Polymer particles are used as binder resins aimed at improving the battery characteristics of lithium-ion secondary batteries, and for the purpose of imparting adhesiveness by coating various substrates. Polymer particles are required to have various properties depending on the application, and various proposals have been made to satisfy these requirements (see, for example, Patent Documents 1 to 3).
• the present invention provides fluorine-containing polymer particles that can form a coating film with excellent adhesiveness and adhesion suppression properties.
• the present invention has the following configuration requirements:
• a first aspect of the present invention is a fluorine-containing polymer particle which satisfies the following (1) and (2): (1)
• the glass transition temperature (Tg) of the fluorine-containing polymer particles is from 60 to 100° C.
• the second invention is characterized in that the fluorine-containing polymer particles contain structural units (X) derived from the fluorine-containing (meth)acrylic acid ester monomer (A) in an amount of 5% by mass or more and less than 30% by mass based on 100% by mass of the monomer.
• R1 represents hydrogen or a methyl group
• R2 represents a fluorine-containing hydrocarbon group having 1 to 10 carbon atoms
• a represents the degree of polymerization.
• the third invention is characterized in that the fluorine-containing polymer particle contains a structural unit (Y-1) derived from a (meth)acrylic acid ester monomer (B) and a structural unit (Y-2) derived from a (meth)acrylic acid ester monomer (B).
• R1 represents a hydrogen atom or a methyl group
• R3 represents a group selected from the group consisting of alicyclic hydrocarbon groups having 5 to 10 carbon atoms
• b represents the degree of polymerization.
• the fourth invention is characterized in that a homopolymer of the structural unit (Y-1) derived from the (meth)acrylic acid ester monomer (B) has a Tg of ⁇ 20 to 70° C., and a homopolymer of the structural unit (Y-2) derived from the (meth)acrylic acid ester monomer (B) has a Tg of 70 to 200° C.
• the fifth invention is a particle formed of a copolymer containing 5% by mass or more and less than 30% by mass of structural unit (X) derived from fluorine-containing (meth)acrylic acid ester monomer (A) in 100% by mass of monomer, 25% by mass or more and 55% by mass or less of structural unit (Y-1) derived from (meth)acrylic acid ester monomer (B) in 100% by mass of monomer, and 25% by mass or more and 55% by mass or less of structural unit (Y-2) derived from (meth)acrylic acid ester monomer (B) in 100% by mass of monomer, in which the structural unit derived from the fluorine-containing (meth)acrylic acid ester monomer (A) is represented by the following general formula (1), and the structural unit derived from the (meth)acrylic acid ester monomer (B) is represented by the following general formula (2).
• structural unit (X) derived from fluorine-containing (meth)acrylic acid ester monomer (A) in 100% by
• a sixth invention is the fifth invention, characterized in that the structural unit (Y-1) derived from the (meth)acrylic acid ester monomer (B) contains at least one of cyclohexyl acrylate, cyclohexyl methacrylate, t-butylcyclohexyl acrylate, and 3,3,5-trimethylcyclohexyl acrylate, and the structural unit (Y-2) derived from the (meth)acrylic acid ester monomer (B) contains at least one of isobornyl acrylate, isobornyl methacrylate, dicyclopentanyl acrylate, and dicyclopentanyl methacrylate.
• the seventh invention is the fifth invention, characterized in that the sum of the structural unit (Y-1) derived from the (meth)acrylic acid ester monomer (B) and the structural unit (Y-2) derived from the (meth)acrylic acid ester monomer (B) is 60% by mass or more and 90% by mass or less.
• the eighth invention is the fifth invention, characterized in that the fluorine-containing polymer particles contain 0.5% by mass or more and 10% by mass or less of a polyfunctional (meth)acrylic acid ester monomer (C) having two or more olefinic double bonds per molecule.
• C polyfunctional (meth)acrylic acid ester monomer
• the ninth invention is a dispersion liquid containing the fluorine-containing polymer particles and water, and the dispersion liquid contains the fluorine-containing polymer particles of any one of the first to eighth inventions, and has a pH of 5.0 or more and 10.0 or less.
• the tenth invention is the ninth invention, characterized in that it is used in a battery separator film.
• the eleventh invention is a battery separator film having fluorine-containing polymer particles according to any one of the first to eighth inventions.
• the twelfth invention is an electrode having fluorine-containing polymer particles according to any one of the first to eighth inventions.
• the present invention provides fluorine-containing polymer particles capable of forming a coating film with excellent adhesiveness and adhesion suppression properties.
• fluorine-containing polymer particles of the present invention By adding the fluorine-containing polymer particles of the present invention to a coating film, it is possible to achieve adhesiveness and adhesion suppression properties.
• the glass transition temperature (Tg) of the fluorine-containing polymer particles of the present invention is 60 to 100°C. By setting the glass transition temperature (Tg) of the fluorine-containing polymer particles to the above range, it is possible to obtain polymer particles with excellent adhesiveness and adhesion suppression properties.
• the upper limit of the glass transition temperature (Tg) of the fluorine-containing polymer particles is preferably less than 100°C, more preferably 90°C or less, even more preferably 80°C or less, and particularly preferably 70°C or less.
• the lower limit of the glass transition temperature (Tg) of the fluorine-containing polymer particles is preferably more than 60°C, more preferably 62°C or more.
• the glass transition temperature (Tg) of the fluorine-containing polymer particles can be adjusted by changing the type and composition ratio of the monomers.
• the "glass transition temperature (Tg) of the fluorine-containing polymer particles” is measured by the following method.
• the aqueous dispersion of polymer particles is freeze-dried to obtain about 10 mg of particle powder, and the measurement is performed using a differential scanning calorimeter (DSC Pyris1 DSC, manufactured by Perkin Elmer) in accordance with JIS K7121:2012.
• DSC Pyris1 DSC manufactured by Perkin Elmer
• a particle membrane is made by hot pressing polymer particles into a sheet of about 1 to 2 mm thickness, and the sample is immersed in a solvent to determine the degree of swelling from the weight increase due to swelling of the sample.
• EC/EMC 3/7
• test pieces are removed from the solvent, the test solvent adhering to the surface of each test piece is wiped off with a wipe or the like, and the weight W of the test piece is then measured.
• VD and VW are the volumes of the test piece before and after immersion in the solvent, respectively, and are calculated by the following formula.
• ⁇ S and ⁇ L are the densities of the polymer and the test liquid, respectively.
• the polymer that constitutes the polymer particles can be obtained, for example, by emulsion polymerization of a monomer mixture consisting of multiple types of (meth)acrylic acid ester monomers and radically polymerizable compounds other than (meth)acrylic acid ester monomers in an aqueous medium.
• the polymer particles of the present invention are copolymers consisting of structural units (X), (Y-1), and (Y-2).
• structural units (X), (Y-1), and (Y-2) are sometimes referred to as "polymer particle units.”
• the structural unit (X) is a repeating unit derived from the fluorine-containing (meth)acrylic acid ester monomer (A) and is represented by the following general formula (1).
• R1 represents hydrogen or a methyl group
• R2 represents a fluorine-containing hydrocarbon group having 1 to 10 carbon atoms
• a represents the degree of polymerization.
• R 1 is independently hydrogen or a methyl group.
• a monomer in which R 1 is hydrogen represents an acrylate
• a monomer in which R 1 is a methyl group represents a methacrylate.
• R2 is a fluorine-containing hydrocarbon group having 1 to 10 carbon atoms, preferably a fluorine-containing hydrocarbon group having 2 to 10 carbon atoms.
• the hydrocarbon group may have an unsaturated bond and may be either a linear hydrocarbon group or a branched hydrocarbon group.
• R2 is a hydrocarbon group in which at least a part of the hydrogen atoms has been substituted with fluorine.
• R2 may be a hydrocarbon group in which all of the hydrogen atoms have been substituted with fluorine.
• R 2 examples include -CH 2 CF 3 , -CH 2 CF 2 CF 2 H, -CH 2 CF 2 CF 3 , -CH 2 CF 2 CFHCF 3 , -CH 2 (CF 2 ) 3 CF 2 H, - CH 2 CH 2 (CF 2 ) 3 CF 3 , -CH 2 (CF 2 ) 5 CF 2 H, -CH 2 CH 2 (CF 2 ) 5 CF 3 , -CH 2 CH 2 (CF 2 ) 7 CF 3 , -CH(CF 3 ) 2 , -CH 2 CCH 3 (CF 3 ) 2 and the like.
• the fluorine-containing (meth)acrylic acid ester monomer (A) has an ester moiety which is a fluorine-containing hydrocarbon group (R 2 ) having 1 to 10 carbon atoms.
• Structural units (Y-1) and (Y-2) are repeating units derived from (meth)acrylic acid ester monomer (B) and are represented by the following general formula (2).
• R1 represents a hydrogen atom or a methyl group
• R3 represents a group selected from the group consisting of alicyclic hydrocarbon groups having 5 to 10 carbon atoms
• b represents the degree of polymerization.
• R 1 represents hydrogen or a methyl group.
• R3 is a group selected from the group consisting of alicyclic hydrocarbon groups having 5 to 10 carbon atoms.
• the structural units (Y-1) and (Y-2) having R3 have different structural units.
• the different structural units mean those having different R3s and/or those being an acrylate and a methacrylate.
• Examples of alicyclic hydrocarbon groups having 5 to 10 carbon atoms include saturated monocyclic groups, polycyclic groups, and bridged ring groups.
• Examples of cyclic hydrocarbon groups having 5 to 10 carbon atoms include cyclohexyl groups, trimethylcyclohexyl groups, t-butylcyclohexyl groups, dicyclopentanyl groups, and isobornyl groups.
• the homopolymer of the structural unit (Y-1) derived from the (meth)acrylic acid ester monomer (B) may have a Tg of -20 to 70°C.
• the homopolymer of the structural unit (Y-2) derived from the (meth)acrylic acid ester monomer (B) may have a Tg of 70 to 200°C.
• the structural unit (Y-1) derived from the (meth)acrylic acid ester monomer (B) may contain at least one of cyclohexyl acrylate, cyclohexyl methacrylate, t-butylcyclohexyl acrylate, and 3,3,5-trimethylcyclohexyl acrylate.
• the structural unit (Y-2) derived from the (meth)acrylic acid ester monomer (B) may contain at least one of isobornyl acrylate, isobornyl methacrylate, dicyclopentanyl acrylate, and dicyclopentanyl methacrylate.
• the copolymer forming the polymer particles contains 5% by mass or more and less than 30% by mass of the structural unit (X) derived from the fluorine-containing (meth)acrylic acid ester monomer (A) in 100% by mass of the monomer, when the monomer unit is taken as 100% by mass.
• the structural unit (X) derived from the fluorine-containing (meth)acrylic acid ester monomer (A) is preferably more than 5% by mass, more preferably 7% by mass or more, and even more preferably 9% by mass or more in 100% by mass of the polymer particle unit.
• the structural unit (X) derived from the fluorine-containing (meth)acrylic acid ester monomer (A) is preferably 28% by mass or less, more preferably 26% by mass or less, and even more preferably 24% by mass or less in 100% by mass of the polymer particle unit.
• the structural units (Y-1) and (Y-2) derived from the (meth)acrylic acid ester monomer (B) are contained in an amount of 25 mass% or more and 55 mass% or less of 100 mass% of the polymer particle units.
• the structural unit (Y-1) derived from the (meth)acrylic acid ester monomer (B) is preferably more than 25 mass%, more preferably 28 mass% or more, even more preferably 31 mass% or more, and even more preferably 34 mass% or more of 100 mass% of the polymer particle units.
• the structural unit (Y-1) derived from the (meth)acrylic acid ester monomer (B) is preferably less than 55 mass%, more preferably 52 mass% or less of 100 mass% of the polymer particle units.
• the structural unit (Y-2) derived from the (meth)acrylic acid ester monomer (B) is preferably more than 25 mass%, more preferably 28 mass% or more of 100 mass% of the polymer particle units.
• the structural unit (Y-2) derived from the (meth)acrylic acid ester monomer (B) is preferably less than 55% by mass, more preferably 52% by mass or less, even more preferably 49% by mass or less, and even more preferably 46% by mass or less, based on 100% by mass of the polymer particle units.
• the total of the structural unit (Y-1) and the structural unit (Y-2) is preferably 60% by mass or more, more preferably 65% by mass or more, and even more preferably 70% by mass or more, based on 100% by mass of the polymer particle unit.
• the total of the structural unit (Y-1) and the structural unit (Y-2) is preferably 90% by mass or less, more preferably less than 85% by mass, and even more preferably 80% by mass or less, based on 100% by mass of the polymer particle unit.
• the polymer particles containing the structural unit (X), the structural unit (Y-1), and the structural unit (Y-2) further contain a polyfunctional (meth)acrylic acid ester monomer (C) having two or more olefinic double bonds per molecule, and thus can form a crosslinked structure upon polymerization.
• polyfunctional monomers (C) having two or more olefinic double bonds per molecule examples include allyl (meth)acrylate, ethylene di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipropylene glycol diallyl ether, polyglycol diallyl ether, triethylene glycol divinyl ether, hydroquinone diallyl ether, tetraallyloxyethane, trimethylolpropane diallyl ether, allyl or vinyl ethers of polyfunctional alcohols other than those mentioned above, triallylamine, methylene bisacrylamide, divinylbenzene, polyalkylene glycol di(meth)acrylate, and urethane acrylate.
• polyalkylene glycol di(meth)acrylate can be preferably used.
• the glass transition temperature (Tg) of the homopolymer formed from the polyfunctional monomer (C) having two or more olefinic double bonds per molecule is -50°C or higher and 0°C or lower.
• the polyfunctional monomer (C) having two or more olefinic double bonds per molecule is preferably contained in an amount of 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, based on 100% by mass of polymer particle units.
• the polyfunctional monomer (C) having two or more olefinic double bonds per molecule is preferably contained in an amount of 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less, based on 100% by mass of monomer units.
• the copolymer forming the polymer particles may contain a repeating unit derived from a radically polymerizable compound as a structural unit other than the structural unit (X), the structural unit (Y-1), and the structural unit (Y-2).
• radically polymerizable compounds that may serve as other structural units include (meth)acrylic acid esters other than the above-mentioned (meth)acrylic acid ester monomers (A) to (C), and vinyl compounds.
• radical polymerizable compound examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, neopentyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-dipropylaminoethyl (meth)acrylate, and 2-diphenyl (meth)acrylate.
• Suitable acrylates include arylaminoethyl, 3-(N,N-dimethylamino)propyl (meth)acrylate, N-(meth)acryloylphthalimide, styrene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, N-vinylpyrrolidone, vinylpyridine, vinyl acetate, hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 7-hydroxyheptyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate. Of these, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and 2-hydroxypropyl acrylate are preferred.
• the volume average particle diameter of the polymer particles is preferably 100 nm or more and 500 nm or less.
• the volume average particle diameter of the polymer particles is preferably more than 100 nm, more preferably 120 nm or more, and even more preferably 150 nm or more.
• the volume average particle diameter of the polymer particles is preferably less than 500 nm, more preferably 450 nm or less, and even more preferably 400 nm or less.
• volume average particle diameter of the polymer particles can be adjusted by changing the type of emulsifier and the monomer composition ratio during polymerization of the polymer particles.
• the particle size distribution of the polymer particles is preferably 1.5 or less, more preferably 1.4 or less, even more preferably 1.3 or less, even more preferably 1.2 or less, and even more preferably 1.1 or less. By keeping the particle size distribution at 1.5 or less, it is possible to suppress a decrease in the uniformity of the coating film containing the polymer particles, which is preferable.
• the particle size distribution of the polymer particles can be adjusted by changing the type of emulsifier, the monomer composition ratio, and the polymerization conditions during polymerization of the polymer particles.
• the average particle size and particle size distribution of the polymer particles can be measured using a particle size distribution measuring device that uses dynamic light scattering as its measurement principle.
• particle size distribution measuring devices include the HORIBA LB-550 and SZ-100 series (both manufactured by Horiba, Ltd.), and the FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.).
• the weight average molecular weight of the polymer constituting the polymer particles of the present invention is preferably 10,000 or more and 1,000,000 or less.
• weight average molecular weight of the polymer refers to the weight average molecular weight in terms of polymethyl methacrylate measured in accordance with JIS K7252-1:2016.
• the polymer particles of the present invention can be mixed with water to prepare a dispersion.
• inorganic particles such as alumina and titania can also be mixed into this dispersion.
• the pH of the dispersion is preferably 5.0 to 10.0, and more preferably 6.0 to 9.5. By adjusting the pH of the dispersion within this range, the dispersion stability can be improved.
• the dispersion containing the polymer particles of the present invention can be used for a film, i.e., applied to the film to form a coating, thereby modifying the surface properties of the film.
• a film i.e., applied to the film to form a coating, thereby modifying the surface properties of the film.
• the film include plastic films, metal films, paper, porous films, porous substrates, conductive films, etc.
• the heating residue of the dispersion containing the polymer particles of the present invention can be measured in accordance with JIS K5601-1-2:2008.
• the heating residue is the mass fraction of the residue obtained by evaporation under specified conditions.
• the heating residue of the dispersion containing the polymer particles is preferably 10.0 to 50.0 mass%, more preferably 20.0 to 45.0 mass%.
• the heating residue of the dispersion containing the polymer particles can be adjusted by changing the type of emulsifier, the monomer composition ratio, and the polymerization conditions during polymerization of the polymer particles.
• the conditions for emulsion polymerization of the monomer mixture are not particularly limited, and for example, the reaction may be carried out in an aqueous medium in the presence of an emulsifier and a polymerization initiator, preferably at a temperature of about 50 to 100°C for about 1 to 30 hours. Chain transfer agents, chelating agents, pH adjusters, solvents, etc. may also be added as necessary.
• anionic surfactants As emulsifiers, anionic surfactants, nonionic surfactants, and combinations of anionic and nonionic surfactants are used. In some cases, amphoteric surfactants or cationic surfactants can also be used.
• anionic surfactants include sodium alkyl sulfate, sodium alkylbenzene sulfonate, sodium succinate dialkyl ester sulfonate, sodium alkyl diphenyl ether disulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, etc.
• sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium lauryl sulfate, etc. are preferred.
• nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, etc. Generally, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, etc. are used.
• amphoteric surfactants include lauryl betaine, sodium hydroxyethyl imidazoline sulfate, and sodium imidazoline sulfonate.
• cationic surfactants include alkylpyridinium chloride, alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, and alkyldimethylbenzylammonium chloride.
• fluorosurfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, perfluoroalkyl phosphates, perfluoroalkyl polyoxyethylenes, perfluoroalkyl betaines, and perfluoroalkoxy fluoroammonium carboxylates can also be used as emulsifiers.
• reactive emulsifiers that are copolymerizable with the above monomers can be used, such as sodium styrenesulfonate, sodium allyl alkylsulfonate, ammonium polyoxyethylene alkyl allyl phenyl ether sulfate, polyoxyethylene alkyl allyl phenyl ether, etc.
• a combination of 2-(1-allyl)-4-nonylphenoxy polyethylene glycol sulfate ester ammonium salt and 2-(1-allyl)-4-nonylphenoxy polyethylene glycol is preferred.
• the amount of emulsifier used is preferably 0.05 to 10 parts by mass per 100 parts by mass of the total amount of the monomer mixture.
• water-soluble polymerization initiators such as sodium persulfate, potassium persulfate, ammonium persulfate, and hydrogen peroxide, or redox-based polymerization initiators that combine these water-soluble polymerization initiators with a reducing agent can be used.
• potassium persulfate or ammonium persulfate is preferred.
• reducing agents include sodium pyrobisulfite, sodium hydrogensulfite, sodium sulfite, sodium thiosulfate, L-ascorbic acid or a salt thereof, sodium formaldehyde sulfoxylate, ferrous sulfate, and glucose.
• L-ascorbic acid or a salt thereof is preferred.
• Oil-soluble polymerization initiators can also be used by dissolving them in a monomer or solvent.
• oil-soluble polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobiscyclohexane-1-carbonitrile, 2,2'-azobisisovaleronitrile, 2,2'-azobisisocapronitrile, 2,2'-azobis(phenylisobutyronitrile), benzoyl peroxide, di-t-butyl peroxide, dilauroyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, t-butyl hydroperoxide, 3,5,5-trimethylhexanol peroxide, and t-butyl peroxy (2-
• the amount of polymerization initiator used is preferably 0.1 to 3 parts by mass per 100 parts by mass of the monomer mixture.
• Chain transfer agents include halogenated hydrocarbons (e.g., carbon tetrachloride, chloroform, bromoform, etc.), mercaptans (e.g., n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-hexadecyl mercaptan, etc.), xanthogens (e.g., dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthogen disulfide, etc.), terpenes (e.g., dipentene, terpinolene, etc.), thiuram sulfides (e.g., tetramethylthiuram monosulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dipenta
• the amount of chain transfer agent used is preferably 0 to 10 parts by mass per 100 parts by mass of the monomer mixture.
• pH adjusters examples include sodium carbonate, potassium carbonate, sodium bicarbonate, and ammonia.
• the amount of pH adjuster used is preferably 0 to 3 parts by mass per 100 parts by mass of the monomer mixture.
• the monomer mixture can be added in various ways.
• addition methods include adding the entire amount of the monomer mixture all at once, charging a portion of the monomer mixture and reacting it, then charging the remaining monomer mixture continuously or in portions, charging a portion of the reacted particles and then charging the remaining monomer mixture continuously or in portions, and charging the entire amount of the monomer mixture continuously or in portions.
• the preferred methods are adding a portion of the monomer mixture and reacting it, then charging the remaining monomer mixture continuously or in portions, or charging a portion of the reacted particles and then charging the remaining monomer mixture continuously or in portions.
• the polymer particles of the present invention can be preferably used as a binder for battery materials.
• a coating on the separator film (battery separator film) of a lithium ion secondary battery it is possible to produce a battery separator film with excellent adhesion to the electrodes.
• adhesion refers to the adhesion between the electrodes and the battery separator film after the electrolyte is injected into the battery.
• conventional battery materials are used, even if the adhesion between the electrodes and the battery separator film is high before the electrolyte is injected, there is a problem that the adhesion decreases after the electrolyte is injected.
• the polymer particles of the present invention it is possible to produce a battery separator film with excellent adhesion to the electrodes with high productivity.
• the battery separator film of the present invention is a battery separator film having a coating film containing the above-mentioned polymer particles on a porous substrate.
• the porous substrate has a structure in which micropores are inside and these micropores are connected from one side to the other side.
• the material constituting the porous substrate is preferably composed of a resin that is electrically insulating, electrically stable, and stable in the electrolyte.
• the resin used is preferably a thermoplastic resin with a melting point of 200°C or less.
• the shutdown function here refers to a function in which, when the lithium-ion secondary battery generates abnormal heat, the porous structure is melted by heat, stopping the movement of ions and stopping discharge.
• thermoplastic resins examples include polyolefin-based resins.
• polyolefin-based resins include polyethylene, polypropylene, ethylene-propylene copolymers, and mixtures of these.
• examples include a single-layer porous substrate containing 90% or more by mass of polyethylene, and a multi-layer porous substrate made of polyethylene and polypropylene.
• the thickness of the battery separator film is preferably 3 ⁇ m or more and 50 ⁇ m or less, and more preferably 5 ⁇ m or more and 30 ⁇ m or less.
• the thickness of the battery separator film 50 ⁇ m or less an increase in the internal resistance of the porous substrate can be suppressed.
• the thickness of the battery separator film 3 ⁇ m or more it becomes possible to manufacture a porous substrate and sufficient mechanical properties can be obtained.
• the air permeability of the battery separator film is preferably 50 sec/100 cc or more and 1,000 sec/100 cc or less. More preferably, it is 50 sec/100 cc or more and 500 sec/100 cc or less. By making the air permeability 50 sec/100 cc or more, sufficient mechanical properties can be obtained. Furthermore, by making it 1,000 sec/100 cc or less, sufficient ion mobility can be obtained, resulting in good battery properties.
• a lithium-ion secondary battery is constructed with a battery separator film and electrolyte between the positive and negative electrodes.
• the positive electrode is a positive electrode material consisting of an active material, a binder resin, and a conductive assistant layered on a current collector.
• the active material include layered lithium-containing transition metal oxides such as LiCoO 2 , LiNiO 2 , and Li(NiCoMn)O 2 , spinel-type manganese oxides such as LiMn 2 O 4 , and iron-based compounds such as LiFePO 4 .
• a resin with high oxidation resistance may be used as the binder resin. Specific examples include fluororesin, acrylic resin, and styrene-butadiene resin. Carbon materials such as carbon black and graphite are used as the conductive assistant.
• Metal foil is suitable as the current collector, and aluminum foil is often used in particular.
• the negative electrode is a negative electrode material made of an active material and a binder resin laminated on a current collector.
• the active material include carbon materials such as artificial graphite, natural graphite, hard carbon, and soft carbon, lithium alloy materials such as tin and silicon, metal materials such as Li, and lithium titanate (Li 4 Ti 5 O 12 ).
• the binder resin include fluororesin, acrylic resin, and styrene-butadiene resin.
• Metal foil is suitable for the current collector, and copper foil is often used in particular.
• the electrolyte is a place where ions move between the positive and negative electrodes in the secondary battery, and is composed of an electrolyte dissolved in an organic solvent.
• the electrolyte include LiPF 6 , LiBF 4 , LiClO 4 and LiTFSI, and LiPF 6 is preferably used from the viewpoint of solubility in organic solvents and ionic conductivity.
• the organic solvent include ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and the like, and two or more of these organic solvents may be mixed and used.
• the polymer particles of the present invention can be preferably used in battery materials other than battery separator films. Specifically, they can be suitably used as a binder resin for electrodes.
• the electrode is the positive electrode or negative electrode of the above-mentioned lithium ion secondary battery.
• the electrode of the present invention is an electrode in which a material containing a binder resin is laminated on a current collector, and the binder resin contains the polymer particles of the present invention.
• volume average particle size, number average particle size and particle size distribution of polymer particles Polymer particles were dispersed in water to a solid content concentration of 0.2% by mass, and the dispersion was measured by dynamic light scattering using ELSZ (manufactured by Otsuka Electronics Co., Ltd.), and analyzed by the Marquardt Method to calculate the volume average particle size and number average particle size. The particle size distribution (volume average particle size/number average particle size) was also calculated from the obtained values.
• Tg Glass Transition Temperature of Polymer Particles
• DSC differential scanning calorimetry
• Swelling degree S of a particle film made of polymer particles in a solvent The particle film made of polymer particles was prepared by molding the polymer particles into a sheet having a thickness of about 1 to 2 mm by hot pressing. The particle film made of polymer particles was immersed as a sample in a solvent, and the swelling degree was calculated from the weight increase due to the swelling of the sample.
• test piece was taken out of the solvent, the test solvent adhering to the surface of each test piece was wiped off with a wipe or the like, and the weight W of the test piece was then measured.
• the swelling degree S was calculated using the following formula:
• VD and VW are the volumes of the sample piece before and after immersion in the solvent, respectively, and were calculated by the following formula.
• ⁇ S is the density of the polymer that constitutes the sample piece
• ⁇ L is the density of the solvent used in the test.
• the swelling degree S was 1.0 or more and less than 2.5, it was rated as “excellent.” If the swelling degree S was 2.5 or more and less than 3.0, it was rated as “good.” If the swelling degree S was 3.0 or more and less than 4.0, it was rated as “slightly poor.” If the swelling degree S was 4.0 or more (including cases where the particles dissolved in the solvent and the particle size could not be measured), it was rated as “poor.” When the swelling degree S was less than 3.0, it was judged to have good swelling inhibition properties.
• Adhesion A coating liquid prepared by diluting an aqueous dispersion of polymer particles with water to a concentration of 5% by mass was applied onto a polyethylene porous substrate using a #10 wire bar, and the substrate was dried at 60° C. for 1 minute in a hot air oven to obtain a porous film having a width of 25 mm and a length of 80 mm.
• An electrode having a width of 20 mm and a length of 70 mm was obtained using graphite as an active material, vinylidene fluoride resin as a binder resin, and carbon black as a conductive assistant.
• This electrode is used as a negative electrode of a lithium ion secondary battery.
• the porous film and the electrode were arranged so that the ends of the electrode and the porous film in the length direction were aligned and overlapped, and the active material of the electrode and the porous layer of the porous film were in contact with each other, and heat pressed under conditions of 80 ° C., 5 MPa, and 7 seconds to bond the electrode and the porous film to prepare a test piece.
• the test piece was placed in an aluminum laminate film that was closed with three pieces to form a bag, and 1 g of electrolyte was soaked into the test piece from the porous film side, and the remaining side of the aluminum laminate film was closed using a vacuum sealer to seal the test piece.
• the aluminum laminate film after sealing the test piece was stored under static conditions for 17 hours in a 60 ° C environment.
• the test piece was removed from the aluminum laminate film, the electrolyte on the surface of the test piece was wiped, and the electrode side of the test piece was attached to an acrylic plate with a thickness of 2 mm. Then, the porous film was peeled in a 180 ° direction, and the adhesion was evaluated as "excellent", “good”, “slightly poor”, and “poor” based on the degree of peeling. "Excellent”: Very good adhesion was exhibited. "Good”: Sufficient adhesion was exhibited. “Slightly poor”: Adhesion was insufficient. "Poor”: No adhesion.
• Example 1 120 parts of ion-exchanged water and 1 part of Adeka Reasorb SR-1025 (emulsifier manufactured by Adeka Corporation) were charged into a reactor, and stirring was started. The reactor was placed under a nitrogen atmosphere, and 0.4 parts of 2,2'-azobis(2-(2-imidazolin-2-yl)propane) (manufactured by Wako Pure Chemical Industries, Ltd.) was added.
• Adeka Reasorb SR-1025 emulsifier manufactured by Adeka Corporation
• Examples 2 to 8 Comparative Examples 1 and 2 Polymer particles were obtained in the same manner as in Example 1, except that the composition ratio of the monomer mixture was changed to the composition shown in Table 1. The evaluation results of the obtained polymer particles are as shown in Table 1.
• composition ratio of the monomers shown in Table 1 is the ratio of each component when the total amount of the monomer components is 100 parts by mass.
• the abbreviations of the components in Table 1 have the following meanings.
• 3FMA 2,2,2-trifluoroethyl methacrylate (in formula (1), R 1 : —CH 3 , R 2 : —CH 2 CF 3 , and a is the degree of polymerization)
• CHA cyclohexyl acrylate (in formula (2), R 1 is —H, R 2 is a cyclohexyl group, and a is the degree of polymerization)
• IBOMA isobornyl methacrylate (in formula (2), R 1 : —CH 3 , R 2 : isobornyl group, and b is the degree of polymerization)
• IBOA isobornyl acrylate (in formula (2), R 1 : —H, R 2 : isobornyl group, and b is the degree
• the polymer particles of the present invention are preferably used as a binder for battery materials.
• the coating on the separator film (battery separator film) of a lithium-ion secondary battery it becomes possible to provide a battery separator film with high adhesion to the electrode with high productivity.
• the promotion of the spread of EVs/PHEVs will contribute to the reduction of greenhouse gas emissions.

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