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WO2013054929A1 - Film poreux de polypropylène et dispositif de stockage électrique - Google Patents

Film poreux de polypropylène et dispositif de stockage électrique Download PDF

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Publication number
WO2013054929A1
WO2013054929A1 PCT/JP2012/076542 JP2012076542W WO2013054929A1 WO 2013054929 A1 WO2013054929 A1 WO 2013054929A1 JP 2012076542 W JP2012076542 W JP 2012076542W WO 2013054929 A1 WO2013054929 A1 WO 2013054929A1
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Prior art keywords
film
porous polypropylene
polypropylene film
polypropylene
temperature
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PCT/JP2012/076542
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English (en)
Japanese (ja)
Inventor
久万　琢也
大倉　正寿
大 西村
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東レ株式会社
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Application filed by 東レ株式会社 filed Critical 東レ株式会社
Priority to JP2013506403A priority Critical patent/JP5354132B2/ja
Priority to CN201280049034.9A priority patent/CN103857733B/zh
Priority to KR1020147008087A priority patent/KR20140081807A/ko
Publication of WO2013054929A1 publication Critical patent/WO2013054929A1/fr

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    • 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
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/20—Manufacture of shaped structures of ion-exchange resins
    • C08J5/22—Films, 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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10—Homopolymers or copolymers of propene
    • C08L23/12—Polypropene
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/52—Separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/02—Diaphragms; Separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • 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
    • H01M50/491—Porosity
    • 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
    • H01M50/494—Tensile strength
    • 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
    • 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
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Definitions

  • the present invention relates to a porous polypropylene film excellent in productivity, air permeability, mechanical properties, and heat resistance, and an electricity storage device using the porous polypropylene film as a separator for an electricity storage device.
  • Porous polypropylene films are being considered for use in a wide range of applications, including separators for batteries and electrolytic capacitors, various separation membranes, clothing, moisture-permeable waterproof membranes for medical applications, reflectors for flat panel displays, and thermal transfer recording sheets. Yes.
  • a porous polypropylene film is suitable as a separator for lithium ion batteries widely used in mobile devices such as notebook personal computers, mobile phones, and digital cameras, electric vehicles, and hybrid vehicles.
  • the characteristics required for porous films for separators include high productivity and low cost, excellent air permeability and high output characteristics when used as a battery, and piercing as an index of dendrite resistance. It is necessary that the strength is high and that the battery is excellent in safety, and further, the heat resistance of the porous film is high, and the safety is ensured even if the temperature of the battery rises during an abnormality. However, in order to increase the mechanical properties and heat resistance, it is necessary to increase the amount of resin per separator thickness to improve the strength, and the porosity and air permeability are reduced. It was difficult to satisfy the characteristics and safety at the same time.
  • Porous methods can be broadly classified into wet methods and dry methods.
  • wet method polyethylene or polypropylene is used as the matrix resin, and the extractables are added and mixed as additives to form a sheet, and then only the additive is extracted using the good solvent of the extractables in the matrix resin.
  • Patent Document 1 various proposals have been made (for example, see Patent Document 1).
  • this method the resin viscosity at the time of extrusion can be lowered by containing a solvent, and film formation with a high molecular weight raw material becomes possible, so that mechanical properties such as puncture strength and tensile strength are improved.
  • the solvent extraction process requires time and labor, and it is difficult to improve productivity.
  • Patent Document 3 describes a porous polypropylene film having high puncture strength.
  • Patent Documents 4 to 11 describe porous polypropylene films having good air permeability.
  • Patent Document 12 also describes a porous polypropylene film having good air permeability in the ⁇ crystal method.
  • these porous polypropylene films have a high porosity in order to improve the air permeability, and the mechanical strength and thermal characteristics may be deteriorated in some cases.
  • JP-A-55-131028 Japanese Patent Publication No.55-32531 JP 2000-30683 A JP 2008-307890 A JP 2008-311220 A JP 2009-39910 A JP 2009-45771 A JP 2010-111182 A JP 2010-171003 A International Publication No. 2010/147149 International Publication No. 2010/008003 International Publication No. 2007/046225
  • the object of the present invention is to solve the above-mentioned problems. That is, the object is to provide a porous polypropylene film excellent in productivity, output characteristics and safety when used as a battery separator.
  • the porous polypropylene film of the present invention is a porous polypropylene film containing a polypropylene resin having ⁇ -crystal forming ability and has a thickness of 10 to 30 ⁇ m and a porosity. Is 55 to 85%, air resistance is 70 to 300 seconds / 100 ml, puncture strength per ⁇ m thickness is 0.18 to 0.50 N / ⁇ m, and heat shrinkage in the width direction when treated at 135 ° C. for 60 minutes. It is characterized by being 12% or less.
  • porous polypropylene film of the present invention is excellent in productivity, air permeability, mechanical strength, and heat resistance, it exhibits excellent ionic conductivity suitable for a separator for an electricity storage device, and is also safe and inexpensive. It can be suitably used as a separator.
  • FIG. 1 is an equivalent circuit used for measuring the separator resistance.
  • the porous polypropylene film of the present invention contains a polypropylene resin (A) having ⁇ -crystal forming ability as the first component.
  • the polypropylene resin (A) is preferably the main component in the porous polypropylene film.
  • Main component means that the proportion of a specific component in all components is 50% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and most preferably 95% by mass. It means that it is more than%.
  • the porous polypropylene film of the present invention has pores that penetrate both surfaces of the film and have air permeability (hereinafter referred to as through-holes).
  • through-holes pores that penetrate both surfaces of the film and have air permeability
  • the porous polypropylene film of the present invention has a total film thickness of 10 to 30 ⁇ m. If the total thickness is less than 10 ⁇ m, the film may break during use, and if it exceeds 30 ⁇ m, the air permeability decreases and the separator is used as a separator. May become too high, making it impossible to obtain a high energy density.
  • the total film thickness is more preferably 12 to 25 ⁇ m, still more preferably 15 to 20 ⁇ m.
  • the porosity of the porous polypropylene film of the present invention is 55 to 85%.
  • the electrical resistance may increase particularly when used as a separator for a high-power battery.
  • the porosity exceeds 85%, mechanical strength such as puncture strength of a film, which is an index of dendrite resistance, may be lowered.
  • the porosity of the film is more preferably 57 to 80%, and particularly preferably 60 to 75%.
  • Porosity depends on the amount of ⁇ -crystal nucleating agent, ethylene / ⁇ -olefin copolymer (B) and dispersant (C) added later, the temperature of the cast drum, the draw ratio and temperature in the longitudinal direction, and the heat treatment step. It is possible to control by controlling the temperature and time of the heat and the relaxation rate in the relaxation zone within the ranges described later.
  • the porous polypropylene film of the present invention has an air permeability resistance of 70 to 300 seconds / 100 ml. More preferably, it is 80 to 250 seconds / 100 ml, and still more preferably 100 to 200 seconds / 100 ml. If the air permeability resistance is less than 70 seconds / 100 ml, mechanical strength such as puncture strength of the film, which is an index of dendrite resistance, may be lowered. When the air resistance exceeds 300 seconds / 100 ml, the output characteristics may be deteriorated particularly when used as a separator for a high-power battery.
  • Air permeation resistance refers to the amount of ⁇ crystal nucleating agent, ethylene / ⁇ -olefin copolymer (B) and dispersant (C) to be described later, the temperature of the cast drum, the draw ratio and temperature in the longitudinal direction, and the transverse draw speed.
  • the temperature and time in the heat treatment step and the relaxation rate in the relaxation zone can be controlled within the ranges described later.
  • the porous polypropylene film of the present invention has a pin puncture strength of 0.18 to 0.50 N / ⁇ m per 1 ⁇ m thickness measured according to JIS Z 1707 (1997) (needle entry speed: 50 mm / min). More preferably, it is 0.20 to 0.45 N / ⁇ m, still more preferably 0.22 to 0.40 N / ⁇ m, and most preferably 0.25 to 0.35 N / ⁇ m.
  • the puncture strength is preferably 0.18 N / ⁇ m or more from the viewpoint of safety when used as a power storage device separator. From the viewpoint of safety, the higher the puncture strength, the better.
  • the porous polypropylene film obtained by the ⁇ crystal method in order to increase the puncture strength to more than 0.50 N / ⁇ m, it is necessary to reduce the porosity and air permeability. In particular, when used as a separator for high-power batteries, the output characteristics may deteriorate.
  • the puncture strength is the amount of ⁇ crystal nucleating agent, ethylene / ⁇ -olefin copolymer (B) and dispersant (C) to be described later, the temperature of the cast drum, the draw ratio and temperature in the longitudinal direction, the transverse draw ratio, The temperature and time in the heat treatment step and the relaxation rate in the relaxation zone can be controlled within the ranges described later.
  • the porous polypropylene film of the present invention has a heat shrinkage in the width direction of 12% or less when treated at 135 ° C. for 60 minutes. More preferably, it is 0.5 to 11%, and further preferably 1 to 10%.
  • the thermal shrinkage rate at 135 ° C. exceeds 12%, for example, when a shutdown layer containing polyethylene is applied to the surface of the porous polyolefin film of the present invention by coating or the like, the polyethylene melts around 135 ° C. to form pores.
  • the plug is closed, the porous polyolefin film as the base material may contract and the battery may be short-circuited.
  • the heat shrinkage ratio depends on the amount of ⁇ crystal nucleating agent, ethylene / ⁇ -olefin copolymer (B) and dispersant (C) added later, the temperature of the cast drum, the stretching ratio and temperature in the longitudinal direction, and the heat treatment step. It is possible to control by controlling the temperature and time of the heat and the relaxation rate in the relaxation zone within the ranges described later.
  • a direction parallel to the film forming direction is referred to as a film forming direction, a longitudinal direction, or an MD direction, and a direction perpendicular to the film forming direction in the film plane is referred to as a width direction or a TD direction.
  • the ⁇ -crystal method is a method of forming a ⁇ -crystal of polypropylene on a cast sheet, forming ⁇ -crystal fibrils oriented in the film-forming direction by longitudinal stretching, and forming a network while cleaving the fibrils by transverse stretching.
  • This is a method for obtaining a polypropylene film.
  • the ⁇ crystal method there is room for improvement in the uniformity of cleavage in the transverse stretching, and the same was true for the uniformity of the pore size of the resulting film.
  • the porous polypropylene film obtained by the ⁇ crystal method in order to improve the puncture strength and the tensile strength, it is necessary to improve the uniformity of the pores and reduce the coarse pores.
  • the pore structure of a porous polypropylene film obtained by a ⁇ crystal method that is, a porous polypropylene film containing a polypropylene resin (A) having ⁇ crystal forming ability is remarkably obtained by adopting raw materials and film forming conditions described later. It has been made uniform to achieve both air permeability, mechanical strength, and heat resistance.
  • a cast sheet shows the unstretched sheet
  • the first component is a polypropylene resin (A) and the second component is a domain that is not completely compatible with the polypropylene resin (A).
  • A polypropylene resin
  • B ethylene / ⁇ -olefin copolymer
  • the air permeability is improved, but the uniformity of the pore size is insufficient, and it is difficult to achieve high strength at the same time.
  • the dispersion diameter of the domain in the TD / ZD cross section of the ethylene / ⁇ -olefin copolymer (B), which is the second component incompatible with the polypropylene resin (A) in the cast sheet is less than 100 nm. Therefore, it is preferable because the pore structure is made uniform and both high air permeability and mechanical strength can be achieved.
  • the domains of polypropylene resin (A) having the ability to form ⁇ crystals, ethylene / ⁇ -olefin copolymer (B), and ethylene / ⁇ -olefin copolymer (B) are fine and uniform.
  • a propylene composition containing a dispersant (C) for dispersion in a film under the film forming conditions described later, since the pore structure is uniformized and both high air permeability and mechanical strength can be achieved. Also, the heat shrinkage rate can be improved. This is considered to be due to the uniform relaxation of the pore structure and uniform relaxation in the heat setting step after transverse stretching.
  • the TD / ZD cross section refers to a cross section when the film is cut along a plane passing through a straight line parallel to the thickness direction and a straight line parallel to the width direction.
  • the ⁇ crystal forming ability of the polypropylene composition is preferably 40 to 90%. If the ⁇ -crystal forming ability is less than 40%, the amount of ⁇ -crystals is small at the time of film production, so the number of voids formed in the film is reduced by utilizing the transition to ⁇ -crystal, and as a result, only a film with low permeability is obtained. It may not be possible.
  • the ⁇ -crystal forming ability is preferably 60 to 85%, particularly preferably 65 to 85%.
  • a polypropylene resin (A) having a high isotactic index can be used, or it can be added to a polypropylene resin (A) called a ⁇ -crystal nucleating agent.
  • a crystallization nucleating agent that selectively forms ⁇ crystals is preferably used as an additive.
  • ⁇ crystal nucleating agents examples include alkali or alkaline earth metal salts of carboxylic acids such as calcium 1,2-hydroxystearate and magnesium succinate, and N, N′-dicyclohexyl-2,6-naphthalenedicarboxyamide.
  • Amide compounds such as 3,9-bis [4- (N-cyclohexylcarbamoyl) phenyl] -2,4,8,10-tetraoxaspiro [5.5] undecane, benzenesulfonic acid
  • aromatic sulfonic acid compounds such as sodium and sodium naphthalene sulfonate, imide carboxylic acid derivatives, phthalocyanine pigments, and quinacridone pigments.
  • amides disclosed in JP-A-5-310665 are preferred.
  • Compound can be preferably used .
  • the content of the ⁇ crystal nucleating agent is preferably 0.05 to 0.5% by mass, more preferably 0.1 to 0.3% by mass, based on the entire polypropylene composition. . If it is less than 0.05% by mass, formation of ⁇ crystals becomes insufficient, and the air permeability of the porous polypropylene film may be lowered. If it exceeds 0.5 mass%, coarse voids are formed, and the puncture strength and tensile strength may be reduced.
  • an isotactic polypropylene resin having a melt flow rate (hereinafter referred to as MFR) of 2 to 30 g / 10 min can be used for extrudability and uniform pore formation. It is preferable from the viewpoint.
  • MFR is an index indicating the melt viscosity of a resin defined in JIS K 7210 (1995), and is a physical property value indicating the characteristics of a polyolefin resin. In the present invention, it refers to a value measured at 230 ° C. and 2.16 kg.
  • the isotactic index of the polypropylene resin (A) is preferably in the range of 90 to 99.9%.
  • the isotactic index of the polypropylene resin (A) is less than 90%, the crystallinity of the resin is lowered, and the film-forming property may be deteriorated or the film strength may be insufficient.
  • the polypropylene resin (A) for forming the porous polypropylene film of the present invention it is possible to use homopolypropylene as well as from the viewpoint of stability in the film forming process, film forming properties, and uniformity of physical properties.
  • a resin obtained by copolymerizing polypropylene with an ethylene component or an ⁇ -olefin component such as butene, hexene, or octene in an amount of 5% by mass or less, more preferably 2.5% by mass or less can also be used.
  • the polypropylene resin (A) may be a combination of homopolypropylene and / or polypropylene copolymer and high molecular weight polypropylene.
  • the polypropylene resin (A) preferably contains a high molecular weight polypropylene in the range of 0.5 to 30% by mass from the viewpoint of improving the strength.
  • the high molecular weight polypropylene is a polypropylene having an MFR of 0.1 to 2 g / 10 min.
  • polypropylene resin D101 manufactured by Sumitomo Chemical Co., Ltd. and polypropylene resins E111G, B241, E105GM manufactured by Prime Polymer Co., Ltd. can be preferably used.
  • the polypropylene composition for forming the porous polypropylene film of the present invention is biaxially stretched to form through-holes, from the viewpoint of improving void formation efficiency during stretching and improving air permeability by increasing the pore diameter.
  • the second component preferably contains an ethylene / ⁇ -olefin copolymer (B).
  • the ethylene / ⁇ -olefin copolymer (B) include linear low-density polyethylene and ultra-low-density polyethylene.
  • octene-1 is copolymerized and has a melting point of 60 to 90 ° C.
  • Copolymer polyethylene resin copolymer PE resin
  • Examples of the copolymerized polyethylene include commercially available resins such as “Engage (registered trademark)” (type names: 8411, 8452, 8100, etc.) manufactured by Dow Chemical.
  • the ethylene / ⁇ -olefin copolymer (B) is contained in an amount of 10% by mass or less when the entire polypropylene composition constituting the porous polypropylene film of the present invention is 100% by mass, from the viewpoint of improving air permeability. To preferred. From the viewpoint of the mechanical properties of the film, it is more preferably 1 to 7% by mass, and more preferably 1 to 4% by mass.
  • the polypropylene composition for forming the porous polypropylene film of the present invention includes an ethylene / ⁇ -olefin copolymer (B) in addition to the polypropylene resin (A) and the ethylene / ⁇ -olefin copolymer (B). It is preferable to contain the dispersant (C) because the pore structure is made uniform and both high air permeability and mechanical strength can be achieved.
  • any dispersant can be used as long as it can increase the dispersibility of the ethylene / ⁇ -olefin copolymer (B) in the polypropylene resin (A).
  • a compatibilizing agent is added, or a high shearing force at the time of extrusion. It is described that fine pores can be formed and the porosity and air permeability can be improved by dispersing them in a polypropylene resin, etc.
  • a polypropylene composition containing the polypropylene resin (A) and the ethylene / ⁇ -olefin copolymer (B) is prepared at a predetermined temperature. It is difficult to make the pore structure of the polypropylene film uniform by dispersing the ethylene / ⁇ -olefin copolymer (B) to a predetermined dispersion diameter only by melting, extruding with high shearing force, etc. is there.
  • the present inventors have developed a highly compatible segment (for example, a polypropylene segment, an ethylene butylene copolymer segment) and a highly compatible segment (E) with an ethylene / ⁇ -olefin copolymer (B) (polypropylene resin (A)).
  • An ethylene / ⁇ -olefin copolymer having a dispersion diameter in a predetermined range in the polypropylene resin (A) by blending a block copolymer each having a polyethylene segment and the like into a polypropylene composition as a dispersant (C).
  • the dispersant (C) include commercially available resins such as olefin crystal, ethylene butylene, olefin crystal block polymer (hereinafter referred to as CEBC) “DYNARON (registered trademark)” manufactured by JSR (type name: 6100P, 6200P, etc.) and olefin block copolymer “INFUSE OBC (registered trademark)” manufactured by Dow Chemical Company.
  • the addition amount of the dispersing agent (C) is preferably 1 to 50 parts by mass, more preferably 5 to 33 parts by mass with respect to 100 parts by mass of the ethylene / ⁇ -olefin copolymer (B).
  • the melting point of the dispersant (C) is ethylene / ⁇ -It is preferably 0 to 60 ° C, more preferably 15 to 30 ° C higher than the melting point of the olefin copolymer (B).
  • an antioxidant In the polypropylene composition forming the porous polypropylene film of the present invention, an antioxidant, a heat stabilizer, an antistatic agent, a lubricant composed of inorganic or organic particles, and further an anti-blocking agent, as long as the effects of the present invention are not impaired.
  • Various additives such as an agent, a filler and an incompatible polymer may be contained.
  • an antioxidant for the purpose of suppressing oxidative deterioration due to the thermal history of the polypropylene resin (A).
  • the addition amount of the antioxidant is preferably 2 parts by mass or less, more preferably 1 part by mass or less, still more preferably 0.5 parts by mass or less with respect to 100 parts by mass of the polypropylene composition.
  • the polypropylene composition for forming the porous polypropylene film of the present invention may contain a pore forming aid made of inorganic or organic particles as long as the effects of the present invention are not impaired.
  • the content is preferably 5 parts by mass or less with respect to 100 parts by mass of the polypropylene composition, more preferably 2 parts by mass or less, and still more preferably 1 part by mass or less.
  • the amount exceeds 5 parts by mass, when used as a separator, the dropped particles may deteriorate battery performance, increase raw material costs, and decrease productivity.
  • the porous polypropylene film of the present invention preferably has a puncture strength of 4.0 to 8.0 N. More preferably, it is 4.2 to 7.0 N, and further preferably 4.5 to 6.0 N.
  • the puncture strength is 4.0 N or more, it can be preferably used as a separator for a high-power, high-capacity electricity storage device that requires particularly high safety such as for vehicles. From the viewpoint of safety, the higher the puncture strength, the better.
  • the puncture strength is determined by setting the addition amount of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C) within the above range, the temperature of the cast drum, the draw ratio and the temperature in the longitudinal direction.
  • the temperature and time in the heat treatment step and the relaxation rate in the relaxation zone can be controlled within the ranges described later.
  • the relationship between porosity ⁇ (%), thickness T ( ⁇ m), and puncture strength S (N) is expressed by the following formula (1) from the viewpoint of achieving both air permeability and mechanical strength. It is preferable to satisfy. S / (T ⁇ (100 ⁇ ) / 100) ⁇ 0.45 (1) If the puncture strength per amount of resin in the thickness direction, which is the value on the left side of the equation (1), is less than 0.45 N / ⁇ m, the air permeability of the film is low and the output characteristics deteriorate when used as a separator, or the puncture strength May decrease.
  • the puncture strength per resin amount in the thickness direction is more preferably 0.5 N / ⁇ m or more.
  • the porous polypropylene film of the present invention preferably has a tensile strength in the width direction of 60 to 200 MPa. More preferably, it is 70 to 180 MPa, and still more preferably 80 to 160 MPa. If the tensile strength is less than 60 MPa, wrinkles are likely to occur in the transport process during film formation, and the yield may be reduced when used as a separator for an electricity storage device. From the viewpoint of safety, the higher the tensile strength, the better. However, in order to make the tensile strength larger than 200 MPa in the porous polypropylene film obtained by the ⁇ crystal method, it is necessary to lower the porosity and air permeability. When used as a separator for high-power batteries, output characteristics may deteriorate.
  • the addition amount of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C) is within the above range, the temperature of the cast drum, and the stretching in the longitudinal direction.
  • the magnification and temperature, the stretching ratio in the width direction, and the temperature and time in the heat treatment step can be controlled within the ranges described later.
  • the porous polypropylene film of the present invention preferably has a Young's modulus in the width direction of 0.5 to 2.0 GPa. More preferably, it is 0.6 to 1.8 GPa, and further preferably 0.7 to 1.6 GPa.
  • the Young's modulus in the width direction is less than 0.5 GPa, when tension is applied in the film-forming direction during film conveyance in film formation or coating, the film may be easily deformed in the width direction and wrinkled. From the viewpoint of film formation stability, the higher the Young's modulus in the width direction, the better.
  • the Young's modulus in the width direction is determined by adjusting the addition amount of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C), the temperature of the cast drum, and the stretching in the longitudinal direction.
  • the magnification and temperature, the stretching ratio in the width direction, and the temperature and time in the heat treatment step can be controlled within the ranges described later.
  • the porous polypropylene film of the present invention preferably has a breaking elongation in the width direction of 20 to 100%. More preferably, it is 25 to 100%, and further preferably 30 to 100%.
  • the elongation at break is less than 20%, film breakage tends to occur in the film forming process, the battery assembling process, etc., and the film forming stability and productivity may be lowered. From the viewpoint of film formation stability, the higher the breaking elongation, the better.
  • the porosity and air permeability In particular, when used as a separator for high-power batteries, the output characteristics may deteriorate.
  • the breaking elongation of the film is increased, the Young's modulus may be decreased.
  • the breaking elongation in the width direction is determined by adjusting the addition amounts of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C), the temperature of the cast drum, and the longitudinal direction.
  • the stretching ratio and temperature, the stretching ratio and stretching temperature in the width direction, and the temperature and time in the heat treatment step can be controlled within the ranges described below.
  • the porous polypropylene film of the present invention preferably has a tensile strength in the film forming direction of 60 to 200 MPa. More preferably, it is 70 to 180 MPa, and still more preferably 80 to 160 MPa.
  • the tensile strength is less than 60 MPa, the film is likely to be broken in the conveying step during film formation, and the yield may be lowered when used as a separator for an electricity storage device. From the viewpoint of safety, the higher the tensile strength, the better.
  • the tensile strength in the film forming direction is determined by adjusting the addition amount of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C) within the above range, the temperature of the cast drum, and the longitudinal direction.
  • the stretching ratio and temperature, the stretching ratio in the width direction, the relaxation rate in the heat treatment step, the temperature and the time can be controlled within the ranges described below.
  • the porous polypropylene film of the present invention preferably has a Young's modulus in the film forming direction of 0.4 to 2.0 GPa. More preferably, it is 0.45 to 1.8 GPa, and most preferably 0.5 to 1.6 GPa. If the Young's modulus in the film forming direction is less than 0.4 GPa, the film is likely to be deformed by the tension in the film forming process, and as a result, wrinkles may be easily formed. From the viewpoint of safety, higher Young's modulus is preferable, but in order to make Young's modulus larger than 2.0 GPa in the porous polypropylene film obtained by the ⁇ crystal method, it is necessary to lower the porosity and air permeability. In particular, when used as a separator for high-power batteries, the output characteristics may deteriorate.
  • the Young's modulus in the film forming direction is determined by adjusting the addition amount of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C) within the above range, the temperature of the cast drum, and the longitudinal direction.
  • the stretching ratio and temperature, the stretching ratio and stretching temperature in the width direction, and the temperature and time in the heat treatment step can be controlled within the ranges described below.
  • the porous polypropylene film of the present invention preferably has a breaking elongation in the film forming direction of 50 to 200%. More preferably, it is 60 to 200%, and most preferably 70 to 200%.
  • breaking elongation in the film forming direction is less than 50%, film tearing is likely to occur when a transfer tension is applied in the film forming direction in the film forming process or the battery assembling process, and the film forming stability and productivity are increased. May decrease. From the viewpoint of film formation stability, the higher the elongation at break, the better.
  • the porosity and permeability It is necessary to lower the temper, and the output characteristics may be deteriorated particularly when used as a separator for a high-power battery.
  • the Young's modulus may be decreased.
  • the elongation at break in the film forming direction is determined by setting the addition amount of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C) within the above range, the temperature of the cast drum, and the longitudinal direction.
  • the stretching ratio and temperature, the stretching ratio and stretching temperature in the width direction, and the temperature and time in the heat treatment step can be controlled within the ranges described below.
  • the porous polypropylene film of the present invention preferably has a maximum pore size of 0.04 to 1.0 ⁇ m. More preferably, it is 0.04 to 0.08 ⁇ m.
  • the maximum pore diameter exceeds 1.0 ⁇ m, a portion having a large pore diameter exists, so that the Young's modulus and the breaking elongation of the porous polypropylene film may be lowered.
  • the maximum pore diameter is less than 0.04 ⁇ m, the air permeability is lowered, and the air permeability of the present invention may not be obtained.
  • the maximum pore size is determined by setting the addition amount of the ⁇ crystal nucleating agent, the ethylene / ⁇ -olefin copolymer (B) and the dispersing agent (C) within the above range, the temperature of the cast drum, the stretching ratio and the temperature in the longitudinal direction.
  • the stretching ratio and stretching temperature in the width direction and the temperature and time in the heat treatment step can be controlled within the ranges described below.
  • the porous polypropylene film of the present invention may have a laminated structure for the purpose of imparting various effects.
  • the number of stacked layers may be a two-layer stack, a three-layer stack, or a larger number of stacks.
  • As a lamination method either a feed block method by co-extrusion or a multi-manifold method, or a method of laminating porous films by lamination may be used.
  • As a laminated structure for example, a layer containing polyethylene can be laminated for the purpose of imparting shutdown properties at low temperatures, or a layer containing particles can be laminated for the purpose of imparting strength and heat resistance.
  • the resin constituting the surface layer does not contain a polyethylene resin or an ethylene copolymer resin.
  • an ethylene component is present in the surface layer, the oxidation resistance may decrease when used as a battery separator. Therefore, when the above-mentioned ethylene / ⁇ -olefin copolymer (B) or dispersant (C) is used, it is possible to take a laminated structure in which a layer using these additives is an inner layer and a layer not used is a surface layer. preferable.
  • the method for producing the porous polypropylene film of the present invention will be described based on a specific example.
  • the manufacturing method of the film of this invention is not limited to this.
  • polypropylene resin (A) 94.5 parts by mass of commercially available homopolypropylene resin (A1) with an MFR of 8 g / 10 min, 5 parts by mass of commercially available homopolypropylene resin (A2) with an MFR of 0.5 g / 10 min, as a ⁇ crystal nucleating agent Feed the raw material from the measuring hopper to the twin screw extruder so that 0.3 parts by mass of N, N'-dicyclohexyl-2,6-naphthalenedicarboxyamide and 0.2 parts by mass of the antioxidant are mixed at this ratio.
  • melt-kneading is performed, it discharges from a die
  • the melting temperature is preferably 270 to 300 ° C.
  • the raw material is fed from the weighing hopper to the twin screw extruder, melt kneaded at 240 ° C., discharged from the die in a strand shape, cooled and solidified in a 25 ° C. water tank, cut into a chip shape, and then the polypropylene raw material (b Prepare).
  • the shear rate at the die it is preferable to set to 100 to 1,000 sec ⁇ 1 during extrusion. More preferably, it is 150 to 800 sec ⁇ 1 , and further preferably 200 to 600 sec ⁇ 1 .
  • the shear rate at the die is expressed by equation (2). If the shear rate at the die is less than 100 sec ⁇ 1 , shearing is not sufficiently performed and it may be difficult to control the domain shape. Further, when the shear rate at the die exceeds 1,000 sec ⁇ 1 , the domain is sheared more than necessary, and it may be difficult to control the domain shape.
  • Shear rate (sec ⁇ 1 ) 6Q / ⁇ Wt 2 (2)
  • t Groove gap (cm)
  • the domain (olefin copolymer (B) mainly composed of the ethylene / ⁇ -olefin copolymer (B) in the cast sheet before stretching is used. It is possible to finely and uniformly disperse the main component (mixed with the dispersant (C)).
  • the average domain diameter (dispersion diameter) of the TD / ZD cross section is preferably 5 to 100 nm, more preferably 10 to 90 nm, and still more preferably 15 to 80 nm. When the domain diameter is less than 5 nm, the effect of promoting fibril cleavage at the time of stretching is small, and air permeability may be lowered.
  • the domain diameter exceeds 100 nm, the size of the hole increases and the puncture strength may be inferior.
  • the domain diameter becomes smaller near the surface layer in the thickness direction where shearing is easily applied, but the domain diameter becomes larger near the center in the thickness direction, resulting in a uniform pore structure.
  • a porous polypropylene film having a highly uniform pore structure is obtained by forming the film in the above range using the dispersant (C) described above. Both air permeability and mechanical strength can be achieved.
  • the flow rate of the polymer is preferably in the range of 40 to 500 kg / hr from the viewpoint of extrusion stability.
  • the groove width of the T die is preferably in the range of 200 to 1,000 mm from the viewpoint of productivity.
  • the groove gap of the T die is preferably in the range of 0.8 to 2 mm from the viewpoint of internal pressure in the extrusion system and casting accuracy.
  • the cast drum preferably has a surface temperature of 105 to 130 ° C. from the viewpoint of controlling the ⁇ crystal fraction of the cast sheet to be high.
  • the forming of the end portion of the sheet affects the subsequent stretchability, and therefore it is preferable that the end portion is sprayed with spot air to be in close contact with the drum. Further, air may be blown over the entire surface using an air knife as necessary from the state in which the entire sheet is in close contact with the drum.
  • the obtained cast sheet is biaxially oriented to form pores in the film.
  • a biaxial orientation method the film is stretched in the longitudinal direction of the film and then stretched in the width direction, or the sequential biaxial stretching method in which the film is stretched in the width direction and then stretched in the longitudinal direction.
  • the simultaneous biaxial stretching method can be used, but it is preferable to adopt the sequential biaxial stretching method in that it is easy to obtain a film having a good balance between air permeability and piercing characteristics, and in particular, after stretching in the longitudinal direction.
  • the film is preferably stretched in the width direction.
  • Specific stretching conditions will be described by taking as an example a sequential biaxial stretching method in which the film is stretched in the longitudinal direction of the film and then stretched in the width direction.
  • a temperature control method for stretching the cast sheet in the longitudinal direction a method using a temperature-controlled rotating roll, a method using a hot air oven, or the like can be adopted.
  • the stretching temperature in the longitudinal direction is preferably 90 to 140 ° C. If it is less than 90 degreeC, a film may fracture
  • the draw ratio is preferably 3 to 7 times.
  • the draw ratio is increased, the air permeability is improved. However, if the film is stretched more than 7 times, the film is easily broken in the next transverse stretching process, or the air permeability becomes too high and the puncture strength is lowered. There is a case. From the viewpoint of achieving both air permeability and puncture strength, the draw ratio is more preferably 4.5 to 6 times.
  • the transverse stretching temperature is preferably 130 to 155 ° C. If it is less than 130 degreeC, a film may fracture
  • the draw ratio in the width direction is preferably 2 to 12 times. If it is less than 2 times, the air permeability may decrease, or the tensile strength in the width direction may decrease. If it exceeds 12 times, the film may break.
  • the film is stretched more preferably 7 to 11 times, still more preferably 7 to 10 times.
  • the transverse stretching speed at this time is preferably 500 to 6,000% / min, more preferably 1,000 to 5,000% / min.
  • the area ratio (longitudinal stretching ratio ⁇ lateral stretching ratio) is preferably 30 to 60 times.
  • the heat treatment step includes a heat setting zone (hereinafter referred to as HS1 zone) in which heat treatment is performed with the width after transverse stretching, and a relaxation zone (hereinafter referred to as Rx zone) in which heat treatment is performed while relaxing the film by narrowing the width of the tenter.
  • HS1 zone heat setting zone
  • Rx zone relaxation zone
  • the heat treatment zone hereinafter referred to as the “HS2 zone”
  • the width after relaxation is divided into three zones, from the viewpoint of both air permeability and mechanical properties, and low heat yield.
  • the temperature of the HS1 zone is preferably 140 to 165 ° C. If it is lower than 140 ° C., the thermal shrinkage in the width direction may increase. If the temperature exceeds 165 ° C, the orientation of the film is too relaxed, the relaxation rate cannot be increased in the subsequent Rx zone, and it is difficult to achieve both air permeability and puncture strength, or the polymer around the pores melts at high temperatures, resulting in air resistance. May become larger. 150 to 160 ° C. is more preferable from the viewpoint of achieving both air permeability and puncture strength.
  • the heat treatment time in the HS1 zone is preferably 0.1 seconds or more and 10 seconds or less from the viewpoint of achieving both the thermal shrinkage in the width direction and the productivity.
  • the relaxation rate in the Rx zone is preferably 13 to 35%. If the relaxation rate is less than 13%, the thermal contraction rate in the width direction may increase. If it exceeds 35%, the air permeability may decrease, or the thickness unevenness or flatness in the width direction may decrease. From the viewpoint of improving the air permeability and reducing the heat shrinkage rate, it is more preferably 15 to 25%.
  • the temperature of the Rx zone is preferably 155 to 170 ° C.
  • the shrinkage stress for relaxation is lowered, and the above-described high relaxation rate may not be achieved or the thermal shrinkage rate in the width direction may be increased.
  • the temperature exceeds 170 ° C., the polymer around the pores may melt at a high temperature and the air permeability may be lowered. From the viewpoint of improving the air permeability and reducing the heat shrinkage rate, the temperature is more preferably 160 to 165 ° C.
  • the relaxation rate in the Rx zone is preferably 100 to 1,000% / min.
  • the relaxation rate is less than 100% / min, it is necessary to slow down the film forming rate or lengthen the tenter length, which may be inferior in productivity. If it exceeds 1,000% / min, the speed at which the film shrinks becomes slower than the speed at which the rail width of the tenter shrinks, the film flutters in the tenter and breaks, or the physical properties in the width direction are uneven and the flatness is lowered. There is a case.
  • the relaxation rate is more preferably 150 to 500% / min.
  • the temperature of the HS2 zone is preferably 155 to 165 ° C.
  • the tension of the film after thermal relaxation becomes insufficient, which may cause uneven physical properties in the width direction and a decrease in flatness, or increase the heat shrinkage rate in the width direction.
  • the higher the HS2 temperature the higher the puncture strength tends to be. If the temperature is lower than 155 ° C., the puncture strength may be insufficient.
  • the temperature exceeds 165 ° C. the polymer around the pores may melt at a high temperature, and the air permeability may be lowered. From the viewpoint of achieving both air permeability and puncture strength, the temperature of the HS2 zone is more preferably 160 to 165 ° C.
  • the heat treatment time in the HS2 zone is preferably 0.1 second or more and 10 seconds or less from the viewpoint of physical property unevenness in the width direction and the compatibility between flatness and productivity.
  • the film after the heat setting step is removed by slitting the ears gripped by the tenter clip, and wound around the core with a winder to obtain a product.
  • the porous polypropylene film of the present invention not only has excellent air permeability and productivity, but also has excellent puncture strength, heat resistance, and extrusion stability, so that it can be used for packaging, hygiene, agricultural, building, medical, and separation. Although it can be used for a film, a light diffusing plate, and a reflective sheet, it can be preferably used particularly as a separator for an electricity storage device.
  • the separator made of the porous polypropylene film of the present invention is provided between the positive electrode and the negative electrode of the electricity storage device, and can efficiently permeate ions in the electrolytic solution while preventing contact between the electrodes.
  • examples of the electricity storage device include a non-aqueous electrolyte secondary battery represented by a lithium ion secondary battery, and an electric double layer capacitor such as a lithium ion capacitor. Since such an electricity storage device can be repeatedly used by charging and discharging, it can be used as a power supply device for industrial devices, household equipment, electric vehicles, hybrid electric vehicles, and the like.
  • the electricity storage device using the separator using the porous polypropylene film of the present invention can be suitably used for industrial equipment and automobile power supply devices because of the excellent characteristics of the separator.
  • the thickness of the porous polypropylene film was measured with a contact-type film thickness meter, Lightmatic VL-50A (10.5 mm ⁇ carbide spherical surface probe, measurement load 0.06 N) manufactured by Mitutoyo Corporation. The measurement was performed 10 times at different locations, and the average value was taken as the thickness of the porous polypropylene film.
  • Air permeability resistance A square having a size of 100 mm ⁇ 100 mm was cut from a porous polypropylene film and used as a sample. Using a B-type Gurley tester of JIS P 8117 (1998), the permeation time of 100 ml of air was measured for the sample at 23 ° C. and a relative humidity of 65%. The measurement was performed three times by changing the sample, and the average value of the permeation time was taken as the air resistance of the film.
  • Puncture strength Using a universal testing machine (Shimadzu Autograph AG-IS), measurement was performed at 23 ° C. according to JIS Z 1707 (1997). The load applied to the film when the sample broke was read and used as the puncture strength (N). The measurement was performed 5 times for each sample, and the average value was evaluated. The puncture strength (N / ⁇ m) per 1 ⁇ m thickness was a value divided by the film thickness of the sample before the test measured by the above method (1).
  • the melting of the ⁇ crystal is the melting peak of the ⁇ crystal, the melting peak of the ⁇ crystal is taken as the melting peak of the base, and the area of the region surrounded by the peak drawn from the flat portion on the high temperature side.
  • ⁇ crystal forming ability The heat of fusion was calibrated using indium.
  • ⁇ crystal forming ability (%) [ ⁇ H ⁇ / ( ⁇ H ⁇ + ⁇ H ⁇ )] ⁇ 100
  • a melting peak having an apex at 140 to 160 ° C. exists, but if it is unclear whether it is caused by the melting of ⁇ crystal, the apex of the melting peak exists at 140 to 160 ° C.
  • the sample prepared under the following conditions has ⁇ crystal forming ability when the K value calculated from each diffraction peak intensity of the diffraction profile obtained by 2 ⁇ / ⁇ scan by the wide angle X-ray diffraction method is 0.3 or more. Judge that it is.
  • the sample preparation conditions and the measurement conditions of the wide angle X-ray diffraction method are shown below.
  • sample The direction of the film is aligned, and the samples are stacked so that the sample thickness after hot press preparation is about 1 mm. This sample is sandwiched between two aluminum plates having a thickness of 0.5 mm, and is hot-pressed at 280 ° C. for 3 minutes to be melted and compressed to make the polymer chain substantially non-oriented. The obtained sheet is crystallized by being immersed in boiling water at 100 ° C. for 5 minutes immediately after being taken out together with the aluminum plate. Then, a sample obtained by cutting a sheet obtained by cooling in an atmosphere at 25 ° C. is used for measurement.
  • X-ray generator 4036A2 (tube type) manufactured by Rigaku Corporation
  • X-ray source CuK ⁇ ray (using Ni filter)
  • Output 40kV, 20mA
  • Optical system Rigaku Denki Co., Ltd., pinhole optical system (2mm ⁇ )
  • Goniometer Rigaku Electric Corporation slit system: 2mm ⁇ (above) -1 ° -1 °
  • Detector Scintillation counter counting and recording device: RAD-C type measurement method manufactured by Rigaku Denki Co., Ltd.
  • Measurement method Transmission type 2 ⁇ / ⁇ scan: Step scan, 2 ⁇ range 10 to 55 °, 0.05 ° step, integration time 2 seconds
  • an X-ray diffraction profile is obtained by 2 ⁇ / ⁇ scanning.
  • the K value is an empirical value indicating the ratio of ⁇ crystals. For details of the K value, such as the calculation method of each diffraction peak intensity, see A.
  • Tm Melting point
  • the raw material polypropylene resin was measured by the same method as the method for measuring the ⁇ crystal forming ability, and the peak temperature ( ⁇ crystal) of the second run was taken as the melting point (Tm). However, the melting point was measured using a polypropylene raw material to which no ⁇ crystal nucleating agent was added.
  • MFR Melt flow rate
  • a tensile test was performed according to JIS K 7127 (1999, test piece type 2), and tensile strength, Young's modulus, and elongation at break were measured.
  • the initial chuck distance was 50 mm, and the tensile speed was 300 mm / min. The measurement was performed 5 times for each sample, and the average value was evaluated.
  • Images obtained by continuously observing from one surface of the cast sheet to the other surface in the thickness direction were collected.
  • a straight line is drawn on the obtained image at an interval of 1 ⁇ m parallel to the thickness direction of the cast sheet, and the dispersion diameter of all the ethylene- ⁇ -olefin polymers (B) existing between the two straight lines is determined. Measured (unit: nm).
  • the dispersion diameter existing between the two straight lines was averaged, and the average value in the thickness direction was calculated.
  • the obtained average dispersion diameter was taken as the dispersion diameter of the ethylene- ⁇ -olefin polymer (B).
  • Example 1 As the polypropylene resin (A), 99.7 parts by mass of homopolypropylene FLX80E4 manufactured by Sumitomo Chemical Co., Ltd. having a melting point of 165 ° C. and an MFR of 7.5 g / 10 min, N, N′-dicyclohexyl-2 which is a ⁇ crystal nucleating agent , 6-Naphthalenedicarboxamide (manufactured by Shin Nippon Rika Co., Ltd., NU-100), 0.3 parts by mass, and IRGANOX 1010 and IRGAFOS168 by Ciba Specialty Chemicals, which are antioxidants, each by 0.1 part by mass
  • the raw material is fed from the weighing hopper to the twin screw extruder so that the mixture is mixed at this ratio, melt kneaded at 300 ° C., discharged from the die in a strand shape, cooled and solidified in a 25 ° C. water tank, and chip-shaped.
  • a polypropylene composition (III) was obtained by cutting into chips.
  • polypropylene composition (I) 73.3 parts by mass, polypropylene composition (II) 10 parts by mass and polypropylene composition (III) 16.7 parts by mass were dry blended and uniaxial melt extrusion for layer A
  • the polypropylene composition (I) is supplied to a single-screw melt extruder for the B layer, melt-extruded at 220 ° C., and foreign matter is removed with a 60 ⁇ m cut sintered filter.
  • a B / A / B composite T die was laminated at a thickness ratio of 1/8/1 and discharged onto a cast drum whose surface temperature was controlled at 125 ° C. to obtain a cast sheet.
  • the domain diameter in the A layer of the cast sheet was 50 nm.
  • the domain diameter in the A layer was about 50 nm both in the vicinity of the surface layer and in the center of the A layer, and was uniform in the thickness direction. Subsequently, it preheated using the ceramic roll heated at 120 degreeC, and stretched 5 times in the longitudinal direction of the film. Next, the edge part was hold
  • heat treatment was performed at 150 ° C. for 2 seconds while maintaining the distance between the clips after stretching (HS1 zone), and further relaxed at 163 ° C. with a relaxation rate of 17% and a relaxation rate of 200% / min (Rx zone). Then, heat treatment was performed at 163 ° C. for 5 seconds while maintaining the distance between the clips after relaxation (HS2 zone). Then, the ear
  • Example 2 80 parts by mass of the polypropylene composition (I) obtained in Example 1, 10 parts by mass of the polypropylene composition (II) and 10 parts by mass of the polypropylene composition (III) were dry blended to produce a uniaxial melt extruder for the A layer.
  • the polypropylene composition (I) is supplied to a uniaxial melt extruder for the B layer, melt extruded at 220 ° C., and foreign matters are removed with a 60 ⁇ m cut sintered filter.
  • a B / A / B composite T die was laminated at a thickness ratio of 1/8/1 and discharged onto a cast drum whose surface temperature was controlled at 120 ° C. to obtain a cast sheet.
  • preheating was performed using a ceramic roll heated to 124 ° C., and the film was stretched 4.8 times in the longitudinal direction of the film.
  • the edge part was hold
  • heat treatment was performed at 151 ° C. for 2 seconds while maintaining the distance between the clips after stretching (HS1 zone), and further relaxation was performed at 163 ° C. with a relaxation rate of 15% and a relaxation rate of 180% / min (Rx zone). Then, heat treatment was performed at 163 ° C. for 5 seconds while maintaining the distance between the clips after relaxation (HS2 zone). Then, the ear
  • Example 3 80 parts by mass of the polypropylene composition (I) obtained in Example 1, 10 parts by mass of the polypropylene composition (II) and 10 parts by mass of the polypropylene composition (III) were dry blended to produce a uniaxial melt extruder for the A layer.
  • the melt was extruded at 220 ° C., and foreign matter was removed with a 60 ⁇ m cut sintered filter, which was then discharged onto a cast drum whose surface temperature was controlled at 120 ° C. using a T die to obtain a cast sheet.
  • preheating was performed using a ceramic roll heated to 120 ° C., and the film was stretched 5.0 times in the longitudinal direction of the film.
  • the edge part was hold
  • heat treatment was performed at 150 ° C. for 2 seconds while maintaining the distance between the clips after stretching (HS1 zone), and at 164 ° C., relaxation was performed at a relaxation rate of 20% and a relaxation rate of 240% / min (Rx zone). Then, heat treatment was performed at 164 ° C. for 5 seconds while maintaining the distance between the clips after relaxation (HS2 zone). Then, the ear
  • Example 4 80 parts by mass of the polypropylene composition (I) obtained in Example 1, 10 parts by mass of the polypropylene composition (II) and 10 parts by mass of the polypropylene composition (III) were dry blended to produce a uniaxial melt extruder for the A layer.
  • the polypropylene composition (I) is supplied to a uniaxial melt extruder for the B layer, melt extruded at 220 ° C., and foreign matters are removed with a 60 ⁇ m cut sintered filter.
  • a B / A / B composite T die was laminated at a thickness ratio of 1/8/1 and discharged onto a cast drum whose surface temperature was controlled at 120 ° C. to obtain a cast sheet.
  • preheating was performed using a ceramic roll heated to 123 ° C., and the film was stretched 4.8 times in the longitudinal direction of the film.
  • the edge part was hold
  • heat treatment was performed at 151 ° C. for 2 seconds while maintaining the distance between the clips after stretching (HS1 zone), and further relaxation was performed at 163 ° C. with a relaxation rate of 15% and a relaxation rate of 180% / min (Rx zone).
  • heat treatment was performed at 163 ° C. for 5 seconds while maintaining the distance between the clips after relaxation (HS2 zone). Then, the ear
  • Engage registered trademark
  • Irganox manufactured by Ciba Specialty Chemicals
  • the domain diameter in the A layer of the cast sheet was 120 nm.
  • the domain diameter in the A layer has a tendency that the domain of about 100 nm is often observed near the surface of the A layer, the domain of about 150 nm is frequently observed in the central part of the A layer, and the domain diameter tends to be larger in the central part. there were.
  • preheating was performed using a ceramic roll heated to 118 ° C., and the film was stretched 5.0 times in the longitudinal direction of the film.
  • the edge part was hold
  • Comparative Example 2 While 90 parts by mass of the polypropylene composition (I) obtained in Example 1 and 10 parts by mass of the polypropylene composition (IV) obtained in Comparative Example 1 were dry-blended and supplied to a uniaxial melt extruder for the A layer.
  • the polypropylene composition (I) was supplied to a single-axis melt extruder for layer B, melt-extruded at 220 ° C., foreign matters were removed with a 60 ⁇ m cut sintered filter, and a feed block type B / A / A B composite T die was laminated at a thickness ratio of 1/8/1 and discharged onto a cast drum whose surface temperature was controlled at 120 ° C. to obtain a cast sheet.
  • preheating was performed using a ceramic roll heated to 125 ° C., and the film was stretched 5.0 times in the longitudinal direction of the film.
  • the edge part was hold
  • relaxation was performed at 160 ° C. with a relaxation rate of 10% and a relaxation rate of 120% / min (Rx zone). Then, the ear
  • Examples that satisfy the requirements of the present invention are not only excellent in air permeability and productivity, but also excellent in puncture strength and heat resistance, and thus can be suitably used as a separator for an electricity storage device.
  • porous propylene film of the present invention is excellent in productivity, air permeability, mechanical properties, and heat resistance, it can be suitably used as a separator for an electricity storage device.

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Abstract

L'invention concerne un film poreux de polypropylène avec d'excellentes propriétés de productivité, de perméabilité à l'air, mécaniques, et de résistance à la chaleur, et un dispositif de stockage électrique. La présente invention concerne un film poreux de polypropylène incluant une résine de polypropylène ayant une capacité à former un cristal β, caractérisé en ce qu'il a une épaisseur de 10‑30 μm, un taux de trous de 55-85%, une résistance à la perméabilité à l'air de 70-300 secondes/100 ml, une résistance à la perforation par 1 μm d'épaisseur de 0,18-0,50 N/μm, et un taux de contraction thermique de 12% ou moins dans le sens de la largeur quand il est traité pendant 60 minutes à 135°C.
PCT/JP2012/076542 2011-10-14 2012-10-12 Film poreux de polypropylène et dispositif de stockage électrique WO2013054929A1 (fr)

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JP2013506403A JP5354132B2 (ja) 2011-10-14 2012-10-12 多孔性ポリプロピレンフィルムおよび蓄電デバイス
CN201280049034.9A CN103857733B (zh) 2011-10-14 2012-10-12 多孔性聚丙烯膜及蓄电装置
KR1020147008087A KR20140081807A (ko) 2011-10-14 2012-10-12 다공성 폴리프로필렌 필름 및 축전 디바이스

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JP2016128533A (ja) * 2015-01-09 2016-07-14 Jnc株式会社 微多孔膜およびその製造方法
JP2016128531A (ja) * 2015-01-09 2016-07-14 Jnc株式会社 微多孔膜およびその製造方法
JPWO2016024533A1 (ja) * 2014-08-12 2017-05-25 東レバッテリーセパレータフィルム株式会社 ポリオレフィン微多孔膜およびその製造方法、非水電解液系二次電池用セパレータ、ならびに非水電解液系二次電池
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JP2018037311A (ja) * 2016-08-31 2018-03-08 住友化学株式会社 非水電解液二次電池用セパレータの製造方法
WO2018187255A1 (fr) 2017-04-06 2018-10-11 Asahi Kasei Kabushiki Kaisha Séparateur pour batterie secondaire au lithium-ion
JP2020147639A (ja) * 2019-03-12 2020-09-17 三菱ケミカル株式会社 多孔性フィルム捲回体、およびその製造方法
EP3652246A4 (fr) * 2017-07-13 2020-11-25 Enzpire Industry Co., Ltd. Emballage médical stérilisable à pores vivants
JP2021504874A (ja) * 2017-11-21 2021-02-15 旭化成株式会社 蓄電デバイス用セパレータ
EP4234206A3 (fr) * 2016-01-29 2023-10-18 Celgard, LLC Améliorations apportées à des séparateurs, à des systèmes de batterie et à des véhicules, ainsi que procédés associés
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KR101851450B1 (ko) 2015-10-29 2018-04-23 스미또모 가가꾸 가부시키가이샤 비수 전해액 이차 전지용 적층 세퍼레이터, 비수 전해액 이차 전지용 부재 및 비수 전해액 이차 전지
US10008706B2 (en) 2015-10-29 2018-06-26 Sumitomo Chemical Company, Limited Laminated separator for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery member, and nonaqueous electrolyte secondary battery
WO2018173904A1 (fr) * 2017-03-22 2018-09-27 東レ株式会社 Membrane microporeuse en polyoléfine et batterie la comprenant
CN109742300B (zh) * 2018-12-28 2021-08-24 界首市天鸿新材料股份有限公司 一种锂电池隔膜及其制备方法

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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013142156A (ja) * 2012-01-06 2013-07-22 Sk Innovation Co Ltd ポリオレフィン系微多孔膜及びその製造方法
JPWO2016024533A1 (ja) * 2014-08-12 2017-05-25 東レバッテリーセパレータフィルム株式会社 ポリオレフィン微多孔膜およびその製造方法、非水電解液系二次電池用セパレータ、ならびに非水電解液系二次電池
JP2016128532A (ja) * 2015-01-09 2016-07-14 Jnc株式会社 微多孔膜およびその製造方法
JP2016128533A (ja) * 2015-01-09 2016-07-14 Jnc株式会社 微多孔膜およびその製造方法
JP2016128531A (ja) * 2015-01-09 2016-07-14 Jnc株式会社 微多孔膜およびその製造方法
US12191441B2 (en) 2015-11-11 2025-01-07 Celgard, Llc Microlayer membranes, improved battery separators, and methods of manufacture and use
EP4234206A3 (fr) * 2016-01-29 2023-10-18 Celgard, LLC Améliorations apportées à des séparateurs, à des systèmes de batterie et à des véhicules, ainsi que procédés associés
JP2017171796A (ja) * 2016-03-24 2017-09-28 三菱ケミカル株式会社 ポリプロピレン系樹脂多孔性フィルム及びその製造方法
JP2018037311A (ja) * 2016-08-31 2018-03-08 住友化学株式会社 非水電解液二次電池用セパレータの製造方法
KR20190128225A (ko) 2017-04-06 2019-11-15 아사히 가세이 가부시키가이샤 리튬-이온 이차 전지 세퍼레이터
US12119513B2 (en) 2017-04-06 2024-10-15 Asahi Kasei Kabushiki Kaisha Separator for lithium-ion secondary battery
WO2018187255A1 (fr) 2017-04-06 2018-10-11 Asahi Kasei Kabushiki Kaisha Séparateur pour batterie secondaire au lithium-ion
EP3652246A4 (fr) * 2017-07-13 2020-11-25 Enzpire Industry Co., Ltd. Emballage médical stérilisable à pores vivants
JP2021504874A (ja) * 2017-11-21 2021-02-15 旭化成株式会社 蓄電デバイス用セパレータ
JP7268004B2 (ja) 2017-11-21 2023-05-02 旭化成株式会社 蓄電デバイス用セパレータ
US11955662B2 (en) 2017-11-21 2024-04-09 Asahi Kasei Kabushiki Kaisha Separator for electric storage device
JP2020147639A (ja) * 2019-03-12 2020-09-17 三菱ケミカル株式会社 多孔性フィルム捲回体、およびその製造方法

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CN103857733B (zh) 2015-08-05
KR20140081807A (ko) 2014-07-01
CN103857733A (zh) 2014-06-11
JPWO2013054929A1 (ja) 2015-04-02
JP5354132B2 (ja) 2013-11-27

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