WO2015190265A1 - Séparateur pour batterie, et procédé de fabrication ce celui-ci - Google Patents

Séparateur pour batterie, et procédé de fabrication ce celui-ci Download PDF

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Publication number
WO2015190265A1
WO2015190265A1 PCT/JP2015/064696 JP2015064696W WO2015190265A1 WO 2015190265 A1 WO2015190265 A1 WO 2015190265A1 JP 2015064696 W JP2015064696 W JP 2015064696W WO 2015190265 A1 WO2015190265 A1 WO 2015190265A1
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Prior art keywords
layer
laminated
polyolefin
microporous membrane
battery separator
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PCT/JP2015/064696
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English (en)
Japanese (ja)
Inventor
水野　直樹
まさみ 菅田
孝一 又野
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東レバッテリーセパレータフィルム株式会社
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Priority to KR1020167032478A priority Critical patent/KR102316033B1/ko
Priority to CN201580030669.8A priority patent/CN106415885B/zh
Priority to JP2015543612A priority patent/JP5876629B1/ja
Publication of WO2015190265A1 publication Critical patent/WO2015190265A1/fr

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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising 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
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H01M50/406—Moulding; Embossing; Cutting
    • 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
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic 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
    • H01M50/443—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
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • 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
    • H01M50/463—Separators, membranes or diaphragms characterised by their shape
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a battery separator having at least a laminated polyolefin microporous membrane suitable for laminating a modified porous layer and a modified porous layer. It is a battery separator useful as a lithium ion battery separator.
  • Thermoplastic resin microporous membranes are widely used as separators and filters.
  • separators for lithium ion secondary batteries nickel-hydrogen batteries, nickel-cadmium batteries, polymer batteries, separators for electric double layer capacitors, and reverse osmosis filtration membranes, ultrafiltration membranes for filters And microfiltration membranes.
  • it is used for moisture permeable waterproof clothing, medical materials, and the like.
  • a separator for a lithium ion secondary battery it has ion permeability when impregnated with an electrolytic solution, is excellent in electrical insulation, electrolytic solution resistance, and oxidation resistance, and has a temperature of about 120 to 150 ° C. when the battery is abnormally heated.
  • a microporous polyethylene membrane having a pore closing effect that blocks ion permeability and suppresses excessive temperature rise is preferably used.
  • a film breakage may occur due to a decrease in the viscosity of the polyethylene constituting the film or a contraction of the film. This phenomenon is not limited to polyethylene, and even when other thermoplastic resins are used, the phenomenon cannot be avoided beyond the melting point of the resin constituting the microporous film.
  • Lithium-ion battery separators are related to battery characteristics, battery productivity, and battery safety, and include mechanical characteristics, heat resistance, permeability, dimensional stability, pore plugging characteristics (shutdown characteristics), and melt-breaking characteristics (meltdown). Characteristics) and the like are required. Furthermore, in order to improve the cycle characteristics of the battery, it is required to improve the adhesion with the electrode material and to improve the electrolyte permeability to improve the productivity.
  • modified porous layer a polyamide-imide resin, a polyimide resin, a polyamide resin and / or a fluorine-based resin excellent in electrode adhesion, which have both heat resistance and electrolyte solution permeability are preferably used.
  • a water-soluble or water-dispersible binder capable of laminating a modified porous layer using a relatively simple washing step and drying step is also widely used.
  • the modified porous layer in the present invention refers to a layer containing a resin that imparts or improves at least one function such as heat resistance, adhesion to an electrode material, and electrolyte permeability.
  • the battery separator needs to increase the area that can be filled in the container in order to improve the battery capacity, and it is predicted that the thinning will proceed.
  • the microporous membrane is likely to be deformed in the planar direction as the thickness of the microporous membrane is reduced, the battery separator in which the modified porous layer is laminated on the microporous membrane is being processed, in the slit process or the battery assembly process.
  • the modified porous layer may peel off, making it more difficult to ensure safety.
  • Patent Document 1 polyvinylidene fluoride is applied to a polyethylene microporous film having a thickness of 9 ⁇ m, and a part of the polyvinylidene fluoride bites into the pores of the polyethylene porous film appropriately so as to express an anchor effect.
  • a composite microporous membrane having a peel strength (T-type peel strength) at the interface between the porous membrane and the polyvinylidene fluoride coating layer of 1.0 to 5.3 N / 25 mm is disclosed.
  • Patent Document 2 a heat-resistant porous layer containing a self-crosslinkable acrylic resin and plate-like boehmite is provided on a corona discharge-treated polyethylene microporous film having a thickness of 16 ⁇ m, and a polyethylene microporous film and a heat-resistant porous layer are provided.
  • a separator having a peel strength at 180 ° (T-type peel strength) of 1.1 to 3.0 N / 10 mm is disclosed.
  • Example 1 of Patent Document 3 47.5 parts by mass of polyethylene having a viscosity average molecular weight of 200,000, 2.5 parts by mass of polypropylene having a viscosity average molecular weight of 400,000, 50 parts by mass of a composition comprising an antioxidant, and 50 liquid paraffins.
  • a polyethylene resin solution consisting of parts by mass is extruded from an extruder at 200 ° C., and a gel-like molded product is obtained while being drawn with a cooling roll adjusted to 25 ° C., and then biaxially stretched so as to be 7 ⁇ 6.4 times.
  • a laminated microporous membrane obtained by laminating a coating layer made of polyvinyl alcohol and alumina particles on the surface of the polyethylene resin microporous membrane is disclosed.
  • Example 6 of Patent Document 4 a polyethylene resin solution having a weight average molecular weight of 41.5 million, a weight average molecular weight of 560,000, a polyethylene composition of 30% by weight and a mixed solvent of liquid paraffin and decalin of 70% by weight is extruded. Extruded from the machine at 148 ° C., cooled in a water bath to obtain a gel-like molded article, and then biaxially stretched to a 5.5 ⁇ 11.0 times to obtain a polyethylene microporous film. A separator for a non-aqueous secondary battery obtained by laminating a coating layer made of meta-type wholly aromatic polyamide and alumina particles on the surface of this polyethylene microporous membrane is disclosed.
  • Example 1 of Patent Document 5 47 parts by mass of homopolymer polyethylene having a viscosity average molecular weight of 700,000, 46 parts by mass of homopolymer polyethylene having a viscosity average molecular weight of 250,000, and 7 parts by mass of homopolymer polypropylene having a viscosity average molecular weight of 400,000 Were dry blended using a tumbler blender.
  • Patent Document 6 discloses a separator for a lithium ion secondary battery in which a ceramic layer is laminated on a porous resin base material having a porous polyethylene layer as an inner layer and a porous polypropylene layer as an outer layer.
  • Patent Document 7 discloses a technique for producing a microporous film by stretching a laminate having a layer to which a low-melting-point resin is added and a layer not containing the layer.
  • Patent Document 8 discloses a separator for a non-aqueous electrolyte battery in which heat resistance at high temperature is improved by laminating an inorganic filler-containing layer on a polyolefin microporous film slightly containing polypropylene.
  • JP 2012-037662 A Republished 2010-104127 Japanese Patent No. 4931083 Japanese Patent No. 4460028 JP 2011-000832 A JP 2011-071009 A Special table 2012-521914 gazette Japanese Patent No. 4789274
  • the present invention assumes the case where the battery separator is made thinner and faster in the future, and the peel strength between the modified porous layer and the laminated polyolefin microporous film is high.
  • An object of the present invention is to provide a battery separator suitable for high-speed processing, in which a modified porous layer is laminated on a polyolefin microporous membrane.
  • FIG. 1 schematically shows the state of the side surface of a laminated sample of a laminated polyolefin microporous membrane and a modified porous layer in a state of being pulled by a tensile tester (not shown).
  • 1 is a laminated sample
  • 2 is a laminated polyolefin microporous membrane
  • 3 is a modified porous layer
  • 4 is a double-sided pressure-sensitive adhesive tape
  • 5 and 5 'are aluminum plates and the arrows in the figure are tensile directions.
  • the aluminum plate (5) and the aluminum plate (5 ′) are pulled in parallel in opposite directions using a tensile tester at a tensile rate of 10 mm / min, and the strength when the modified porous layer is peeled is measured.
  • the peel strength is 130 N / 15 mm or more in this evaluation method, the laminated modified porous layer is being transported or processed even if the thickness of the laminated polyolefin microporous film is, for example, 10 ⁇ m or less. There is almost no peeling phenomenon.
  • the T-type peel strength or 180 ° peel strength conventionally used as a peel strength measurement method is the peel force when the coating layer is peeled from the surface of the battery separator vertically or obliquely backward. is there. According to this evaluation method, it is possible to evaluate the abrasion resistance in the slit process and the battery assembly process more practically as compared with these conventional evaluation methods.
  • the battery separator of the present invention has the following configuration. That is, A battery separator having a laminated polyolefin microporous membrane and a modified porous layer present on at least one surface thereof, wherein the laminated polyolefin microporous membrane comprises at least a layer A and a B layer.
  • the laminate has a meltdown temperature of 165 ° C. or higher, an air resistance of 300 sec / 100 cc Air or less, and at least one surface facing the outside is 3 / cm 2 or more and 200 / cm 2 or less.
  • Protrusions made of polyolefin are irregularly present, and the protrusions satisfy 0.5 ⁇ m ⁇ H (H is the height of the protrusions) and 5 ⁇ m ⁇ W ⁇ 50 ⁇ m (W is the size of the protrusions).
  • battery separator comprising a can the be stacked on a surface having a projection of the laminated polyolefin microporous membrane, and a tensile strength of 5N / mm 2 or more binders and inorganic particles A.
  • the surface facing the outside world means that at least one of the surfaces of each layer constituting the laminated polyolefin microporous membrane faces the side (interface side) in contact with the surface of the other layer, but on the interface side.
  • the laminated polyolefin microporous membrane preferably has a three-layer structure of A layer / B layer / A layer or B layer / A layer / B layer, and the B layer has a heat of fusion of 90 J / g or more. More preferably, it comprises polypropylene which is In the battery separator of the present invention, the thickness of the B layer is preferably 3 ⁇ m or more and 15 ⁇ m or less.
  • the binder preferably contains polyvinyl alcohol or an acrylic resin.
  • the inorganic particles preferably contain at least one selected from the group consisting of calcium carbonate, alumina, titania, barium sulfate and boehmite.
  • the battery separator manufacturing method of the present invention has the following configuration.
  • Step of adding a molding solvent to the polyolefin resin constituting the A layer and then melt-kneading to prepare the polyolefin resin solution A (b) Molding into a polyolefin resin containing the polyethylene resin and polypropylene resin constituting the B layer
  • Extruding the polyolefin resin solutions A and B obtained in steps (a) and (b) from a die at least one of them Is cooled with a cooling roll having a surface from which the forming solvent has been removed by the forming solvent removing means to form a laminated gel-like molded product
  • the forming solvent removing means in the step (c) is preferably a means for scraping off using a doctor blade.
  • a separator for a battery in which the modified porous layer is laminated on the laminated polyolefin microporous membrane having excellent adhesion to the modified porous layer does not cause peeling of the modified porous layer even during high-speed conveyance. Is obtained.
  • the laminated polyolefin microporous membrane used in the present invention is suitable for the surface by adjusting the specific polyolefin resin solution and highly controlling the cooling rate of the polyolefin resin solution extruded from the extruder through the die. It has shape and number of protrusions.
  • the present invention when a modified porous layer containing inorganic particles and a binder having a tensile strength of 5 N / mm 2 or more is laminated on a laminated polyolefin microporous membrane, the present invention is provided between the laminated polyolefin microporous membrane and the modified porous layer. With this, extremely excellent peel strength can be obtained.
  • the projection referred to in the present invention is essentially different from the projection obtained by adding, for example, inorganic particles to the laminated polyolefin microporous film.
  • the protrusions obtained by adding inorganic particles to the laminated polyolefin microporous membrane are usually extremely small in height, and if a protrusion with a height of 0.5 ⁇ m or more is to be formed by the same means, the laminated polyolefin microporous film It is necessary to add particles having a particle size equal to or greater than the thickness of the film. However, when such particles are added, the strength of the laminated polyolefin microporous film is lowered, which is not realistic.
  • the protrusions referred to in the present invention are those in which a part of the surface layer of the laminated polyolefin microporous membrane is grown to a moderately raised shape, and do not deteriorate the basic characteristics of the laminated polyolefin microporous membrane. .
  • the irregularly scattered protrusions referred to in the present invention are arranged with regularity or periodicity obtained by passing through an embossing roll before or after the stretching process in the production of a laminated polyolefin microporous film. It is clearly different from the protrusion. Press work such as embossing is basically not preferred because it forms protrusions by compressing and tends to cause a decrease in air resistance and electrolyte permeability.
  • the moderately shaped protrusion as used in the present invention means a protrusion having a size of 5 ⁇ m or more and 50 ⁇ m or less and a height of 0.5 ⁇ m or more. That is, 5 ⁇ m ⁇ W ⁇ 50 ⁇ m (W is the size of the protrusion) and 0.5 ⁇ m ⁇ H (H is the height of the protrusion).
  • Such protrusions function as anchors when the modified porous layer is laminated on the laminated polyolefin microporous membrane, and as a result, the battery separator having a large 0 ° peel strength is obtained.
  • the upper limit of the height is not particularly limited, but 3.0 ⁇ m is sufficient.
  • the 0 ° peel strength is affected by the number of protrusions having a height of 0.5 ⁇ m or more and the average height thereof.
  • the lower limit of the number of protrusions is preferably 3 / cm 2 , more preferably 5 / cm 2 , and still more preferably 10 / cm 2 .
  • the upper limit of the number of protrusions is preferably 200 / cm 2 , more preferably 150 / cm 2 .
  • the lower limit of the height of the protrusion is preferably 0.5 ⁇ m, more preferably 0.8 ⁇ m, and still more preferably 1.0 ⁇ m.
  • protrusion in this invention say the value measured with the measuring method mentioned later.
  • the increasing range of the air resistance referred to in the present invention means a difference between the air resistance of the laminated polyolefin microporous membrane and the air resistance of the battery separator, and is preferably 90 seconds / 100 cc Air or less. Preferably it is 80 cc Air, more preferably 50 cc Air.
  • the upper limit of the thickness of the laminated polyolefin microporous membrane used in the present invention is preferably 25 ⁇ m, more preferably 20 ⁇ m, and even more preferably 16 ⁇ m.
  • the lower limit is preferably 7 ⁇ m, more preferably 9 ⁇ m.
  • the meltdown temperature of the polyolefin laminated microporous membrane of the present invention is 165 ° C. or higher, more preferably 170 ° C. or higher. If the meltdown temperature is within the above range, the stability of the battery is increased because the dimensional stability is high even at high temperatures.
  • the upper limit of the air resistance of the laminated polyolefin microporous membrane is preferably 300 sec / 100 cc Air, more preferably 200 sec / 100 cc Air, still more preferably 150 sec / 100 cc Air, and the lower limit is preferably 50 sec / 100 cc Air, more preferably 70 sec. / 100 cc Air, more preferably 100 sec / 100 cc Air.
  • the upper limit of the porosity of the laminated polyolefin microporous membrane is preferably 70%, more preferably 60%, and even more preferably 55%.
  • the lower limit is preferably 30%, more preferably 35%, still more preferably 40%.
  • the average pore size of the laminated polyolefin microporous membrane greatly affects the pore closing performance, and is preferably 0.01 to 1.0 ⁇ m, more preferably 0.05 to 0.5 ⁇ m, and still more preferably 0.1 to 0. .3 ⁇ m.
  • the 0 ° peel strength of the modified porous layer can be sufficiently obtained by the anchor effect of the functional resin, and when the modified porous layer is laminated, The air resistance is not greatly deteriorated, and the response to the temperature of the hole closing phenomenon is not slowed, and the hole closing temperature due to the heating rate is not shifted to a higher temperature side.
  • the polyolefin microporous film constituting the A layer of the present invention contains polyethylene as a main component.
  • the polyethylene content is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass, based on 100% by mass of the entire polyolefin resin. It is.
  • polyethylene high density polyethylene such as density exceeding 0.94 g / cm 3, density polyethylene in the range density of 0.93 ⁇ 0.94g / cm 3, density of from 0.93 g / cm 3
  • low density polyethylene linear low density polyethylene, ultra high molecular weight polyethylene and the like
  • the ultra high molecular weight polyethylene may be not only a homopolymer of ethylene but also a copolymer containing a small amount of other ⁇ -olefin.
  • the ⁇ -olefin include propylene, butene-1, hexene-1, pentene-1, 4-methylpentene-1, octene, vinyl acetate, methyl methacrylate, styrene and the like.
  • the laminated film particularly when produced by a coextrusion method, it may be difficult to control the physical property unevenness in the width direction due to the difference in viscosity of each layer, but by using ultrahigh molecular weight polyethylene for the A layer, Since the molecular network of the entire membrane is strengthened, non-uniform deformation hardly occurs, and a microporous membrane having excellent physical property uniformity can be obtained.
  • the weight average molecular weight (hereinafter referred to as Mw) of the high density polyethylene is preferably 1 ⁇ 10 5 or more, more preferably 2 ⁇ 10 5 or more.
  • the upper limit is preferably 8 ⁇ 10 5 for Mw, more preferably 7 ⁇ 10 5 for Mw. If Mw is in the above range, the stability of the film formation and the finally obtained puncture strength can both be achieved.
  • the Mw of the ultra high molecular weight polyethylene is preferably 1 ⁇ 10 6 or more and less than 4 ⁇ 10 6 .
  • the Mw of the ultra high molecular weight polyethylene having an Mw of 1 ⁇ 10 6 or more and less than 4 ⁇ 10 6 , the pores and fibrils can be miniaturized and the puncture strength can be increased. Further, if Mw is 4 ⁇ 10 6 or more, the viscosity of the melt becomes too high, so that there may be a problem in the film forming process such that the resin cannot be extruded from the die.
  • the content of ultrahigh molecular weight polyethylene is 100% by mass with respect to the entire polyolefin resin, and the lower limit is preferably 2% by mass, more preferably 18% by mass.
  • the upper limit is preferably 45% by mass, more preferably 40% by mass. Within this range, both puncture strength and air resistance can be easily achieved.
  • the content of the ultrahigh molecular weight polyethylene is within the preferred range, a sufficiently high protrusion can be obtained.
  • the modified porous layer is laminated by the protrusions, the protrusions function as anchors, and extremely strong peeling resistance can be obtained against the force applied in parallel to the surface direction of the polyethylene porous film. Further, even when the thickness of the polyethylene porous film is reduced, sufficient tensile strength can be obtained.
  • the tensile strength has no particular upper limit, but is preferably 100 MPa or more.
  • the B layer of the present invention is a microporous film mainly composed of polyolefin.
  • the B layer preferably contains 50% by mass or more of high-density polyethylene from the viewpoint of strength.
  • the weight average molecular weight (hereinafter referred to as Mw) of the high density polyethylene is preferably 1 ⁇ 10 5 or more, more preferably 2 ⁇ 10 5 or more.
  • the upper limit of Mw is preferably 8 ⁇ 10 5 for Mw, more preferably 7 ⁇ 10 5 for Mw. If Mw is in the above range, the stability of the film formation and the finally obtained puncture strength can both be achieved.
  • the B layer contains polypropylene.
  • polypropylene When polypropylene is added, the meltdown temperature can be further improved when the polyolefin microporous membrane of the present invention is used as a battery separator.
  • a block copolymer and a random copolymer can be used in addition to the homopolymer.
  • the block copolymer and random copolymer can contain a copolymer component with an ⁇ -olefin other than propylene, and ethylene is preferable as the other ⁇ -olefin.
  • the Mw of polypropylene is preferably 5 ⁇ 10 5 or more, more preferably 6.5 ⁇ 10 5 or more, and further preferably 8 ⁇ 10 5 or more. When Mw is within the above range, a film having a uniform film thickness can be obtained without deteriorating the dispersibility of polypropylene during sheet formation.
  • the heat of fusion ( ⁇ Hm) of polypropylene is preferably 90 J / g or more, more preferably 95 J / g. When ⁇ Hm is within the above preferred range, good meltdown characteristics can be obtained.
  • the content of polypropylene is preferably less than 60% by mass relative to the total mass of the polyolefin composition. If it is 60% by mass or more, the permeability may be deteriorated. In particular, in the case where the surface layer is a B layer, the amount of powder generated due to polypropylene dropping when the laminated microporous membrane is slitted increases. If the amount of powder generated due to the falling off of polypropylene is large, defects such as pinholes and black spots may occur in the laminated microporous film.
  • the lower limit of the addition amount is preferably 3% by mass or more, more preferably 10% by mass, and still more preferably 20% by mass or more. When the content of polypropylene is within the above preferred range, good meltdown characteristics can be obtained.
  • the B layer also contains ultrahigh molecular weight polyolefin.
  • the ultra high molecular weight polyolefin include ultra high molecular weight polyethylene and ultra high molecular weight polypropylene exemplified in the A layer.
  • the polyolefin microporous membrane of the present invention is an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, and further an antiblocking agent and a filling material, as long as both the A layer and the B layer do not impair the effects of the present invention.
  • Various additives such as materials may be included.
  • an antioxidant for the purpose of suppressing oxidative deterioration due to the thermal history of the polyolefin resin.
  • Appropriate selection of the type and amount of the antioxidant and heat stabilizer is important for adjusting or enhancing the characteristics of the microporous membrane.
  • the laminated polyolefin microporous membrane used in the present invention preferably contains substantially no inorganic particles.
  • substantially free of inorganic particles means, for example, a content that is 50 ppm or less, more preferably 10 ppm or less, and even more preferably a detection limit or less when inorganic elements are quantified by fluorescent X-ray analysis. To do. Even if particles are not actively added to the laminated polyolefin microporous membrane, contaminants derived from foreign substances and dirt attached to the lines and equipment in the manufacturing process of the raw resin or polyolefin microporous membrane are peeled off. It may be mixed in the film and may be detected at 50 ppm or less.
  • the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyolefin resin composition of the B layer together with the A layer is preferably in the range of 5 to 200, more preferably 10 to 100. is there.
  • Mw / Mn is the above preferred range, extrusion of the polyolefin solution is easy. Further, the polyolefin microporous membrane can obtain a sufficient number of protrusions on the surface, and sufficient mechanical strength can be obtained even when the thickness of the polyolefin microporous membrane is reduced.
  • Mw / Mn is used as a measure of molecular weight distribution.
  • Mw / Mn of a single polyolefin can be appropriately adjusted by multistage polymerization of polyolefin.
  • Mw / Mn of the mixture of polyolefin can be suitably adjusted by adjusting the molecular weight and mixing ratio of each component.
  • the present inventors consider the mechanism by which protrusions are formed in the present invention as follows.
  • the resin solution of the melted polyolefin resin and the molding solvent is extruded from the die, and at the same time, the crystallization of the polyolefin is started.
  • the crystallization rate is increased by contacting the cooling roll and quenching.
  • a spherulite having a symmetric structure having a crystal nucleus is formed (FIG. 2).
  • the heat transfer rate between the cooling roll surface and the molten polyolefin resin is relatively low, the crystallization rate is low, and as a result, spherulites having relatively small crystal nuclei are formed.
  • the spherulite When the heat transfer rate is high, the spherulite has a relatively large crystal nucleus.
  • the crystal nuclei of these spherulites become protrusions during TD (width direction) and / or MD (machine direction) stretching, which is a subsequent process.
  • Spherulites appear as ring-shaped marks on the surface of the laminated polyolefin microporous membrane (FIG. 3).
  • a laminated polyolefin microporous membrane can be freely selected according to the purpose as long as it satisfies the above various characteristics.
  • Microporous membrane production methods include the foaming method, phase separation method, dissolution recrystallization method, stretch pore opening method, powder sintering method, etc. Among these, in terms of homogenizing fine pores and cost, A separation method is preferred.
  • a polyolefin resin and a molding solvent are heated and melt-kneaded, and the obtained molten mixture is extruded from a die and cooled to form a gel-like molded product, and the obtained gel-like product is obtained.
  • examples include a method of obtaining a microporous film by stretching the molded product in at least a uniaxial direction and removing the molding solvent.
  • the method for producing a laminated polyolefin microporous membrane of the present invention includes the following steps (a) to (f).
  • Step of stretching in the width direction to obtain a laminated stretched molded product Step of extracting and removing the molding solvent from the laminated stretched molded product and drying to obtain a laminated porous molded product ( )
  • a step of heat-treating the laminated porous molded article to obtain a laminated polyolefin microporous membrane before the step (a), during the steps (a) to (f), or after the step (f), a hydrophilic treatment, Other steps such as charge removal processing can be added. Moreover, a redrawing process can also be provided after a process (f).
  • a molding solvent for example, nonane, decane, undecane, dodecane, liquid paraffin and other aliphatic or cyclic hydrocarbons, or mineral oil fractions with boiling points corresponding to these, gel-like molded products with a stable solvent content
  • Nonvolatile solvents such as liquid paraffin are preferred for obtaining.
  • the dissolution by heating is performed by a method in which the polyolefin composition is dissolved at a temperature at which the polyolefin composition is completely dissolved by stirring or uniformly mixing in an extruder.
  • the temperature varies depending on the polymer and solvent to be used when it is dissolved in an extruder or in a solvent while stirring, but it is preferably in the range of 140 to 250 ° C., for example.
  • the concentration of the polyolefin resin is preferably 15 to 40% by mass, more preferably 25 to 40% by mass, and further preferably 28 to 35% by mass, where the total of the polyolefin resin and the molding solvent is 100% by mass.
  • concentration of the polyolefin resin is within the above preferable range, a sufficient number of crystal nuclei for forming protrusions are formed, and a sufficient number of protrusions are formed. Further, swell and neck-in are suppressed at the die outlet when extruding the polyolefin resin solution, and the moldability and self-supporting property of the extruded molded body are maintained.
  • a laminated microporous membrane having a structure (gradient structure) in which the average pore diameter is changed in the film thickness direction can be obtained.
  • the average pore diameter of the layer formed using the resin solution having the lower concentration is larger than the average pore diameter of the layer formed using the resin solution having the higher concentration.
  • Which concentration of the resin solution A or B is to be increased can be appropriately selected according to the physical properties required for the laminated microporous membrane. For example, if the inner layer is a dense structure layer of 0.01 to 0.05 ⁇ m and the surface layer is a coarse structure layer 1.2 to 5.0 times the dense structure layer, the balance between ion permeability and pin puncture strength is improved. be able to.
  • the method of melt kneading is not particularly limited, but is usually performed by uniformly kneading in an extruder. This method is suitable for preparing highly concentrated solutions of polyolefins.
  • the melt kneading temperature varies depending on the polyolefin resin used. For example, since the polyethylene composition has a melting point of about 130 to 140 ° C., the lower limit of the melt kneading temperature is preferably 140 ° C., more preferably 160 ° C., and most preferably 170 ° C. The upper limit is preferably 250 ° C, 230 ° C, and most preferably 200 ° C.
  • the polyolefin solution contains polypropylene, and the melt kneading temperature in that case is preferably 190 to 270 ° C.
  • the melt kneading temperature is preferably low, but if it is lower than the above-mentioned temperature, an unmelted product is generated in the extrudate extruded from the die, causing film breakage or the like in the subsequent stretching step. It may be a cause.
  • the temperature is higher than the above-described temperature, the thermal decomposition of the polyolefin becomes violent, and the properties of the resulting microporous film, for example, puncture strength, tensile strength, etc., may be inferior.
  • the ratio (L / D) of the screw length (L) to the diameter (D) (L / D) of the twin screw extruder is preferably 20 to 100 from the viewpoint of obtaining good process kneadability and resin dispersibility / distributability.
  • the lower limit is more preferably 35.
  • the upper limit value is more preferably 70.
  • L / D is 20 or more, melt-kneading is sufficient.
  • L / D is 100 or less, the residence time of the polyolefin solution does not increase excessively.
  • the inner diameter of the twin-screw extruder is preferably 40 to 100 mm.
  • the screw rotation speed (Ns) of the twin screw extruder is 150 rpm or more.
  • Ratio of extrusion rate Q (kg / h) of polyolefin solution to Ns (rpm), Q / Ns is preferably 0.64 kg / h / rpm or less, more preferably 0.35 kg / h / rpm or less.
  • the polyolefin resin solutions A and B obtained in (a) and (b) are extruded from a die, and at least one of them is a cooling roll having a surface from which the molding solvent is removed by the molding solvent removing means.
  • the step of cooling and forming a laminated gel-like molded product The polyolefin resin solutions A and B melted and kneaded by an extruder are pushed up from a die directly or through another extruder and cooled by a cooling roll. Then, a laminated gel-like molded product is formed.
  • a method for obtaining a laminated gel-like molded product it is desirable to separately prepare gel-like molded products to be laminated, and then stick them together through a calender roll or the like (sticking method), or supply a polyolefin solution separately to an extruder as desired. Any method may be used such as a method of melting at a temperature of 5 ° C, joining in a polymer tube or die, coextrusion and laminating, and then forming a laminated gel-like molded product (coextrusion method). From the viewpoint of adhesion, it is preferable to use a coextrusion method.
  • the gel-like molded product is formed by bringing the polyolefin resin solution extruded from the die into contact with a rotating cooling roll set at a surface temperature of 20 ° C. to 40 ° C. with a refrigerant.
  • the extruded polyolefin resin solution is preferably cooled to 25 ° C. or lower.
  • the cooling rate in the temperature range where crystallization is substantially performed becomes important.
  • the extruded polyolefin resin solution is cooled at a cooling rate of 10 ° C./second or more in a temperature range where crystallization is substantially carried out to obtain a gel-like molded product.
  • the cooling rate is preferably 20 ° C./second or more, more preferably 30 ° C./second or more, and further preferably 50 ° C./second or more.
  • the cooling rate can be estimated by simulating from the extrusion temperature of the gel-shaped molded product, the thermal conductivity of the gel-shaped molded product, the thickness of the gel-shaped molded product, the molding solvent, the cooling roll, and the heat transfer coefficient of air.
  • the polyolefin resin solution is cooled by being wound around a rotating cooling roll to become a gel-like molded product, but the molding solvent adheres to the surface of the cooling roll after the gel-like molded product is pulled apart.
  • the polyolefin resin solution is cooled by being wound around a rotating cooling roll to become a gel-like molded product, but the molding solvent adheres to the surface of the cooling roll after the gel-like molded product is pulled apart.
  • the cooling rate becomes slow due to the heat insulating effect, and it becomes difficult to form protrusions. Therefore, it is important to remove the forming solvent as much as possible before the cooling roll comes into contact with the polyolefin resin solution again.
  • the method for removing the molding solvent that is, the method for removing the molding solvent from the cooling roll is not particularly limited, but the doctor blade is placed on the cooling roll so as to be parallel to the width direction of the gel-like molded article and passed through the doctor blade.
  • a method is preferably employed in which the molding solvent is scraped off to the extent that the cooling roll surface is invisible until immediately after the gel-like molded product comes into contact.
  • it can be removed by means such as blowing with compressed air, suction, or a combination of these methods.
  • the method of scraping off using a doctor blade is preferable because it can be carried out relatively easily, and it is more preferable to use a plurality of doctor blades in order to improve the removal efficiency of the forming solvent.
  • the material of the doctor blade is not particularly limited as long as it is resistant to the molding solvent, but is preferably made of resin or rubber rather than metal. If it is made of metal, the cooling roll may be scratched.
  • the resin doctor blade include polyester, polyacetal, and polyolefin.
  • the thickness of the polyolefin resin solution during extrusion is preferably 1500 ⁇ m or less, more preferably 1000 ⁇ m or less, and still more preferably 800 ⁇ m or less.
  • the cooling rate on the surface on the side of the cooling roll is preferably not slow.
  • the bonding method when a laminated gel-like molded product is obtained by the bonding method, if at least one of the polyolefin resin solutions to be the A layer or the B layer is formed as a gel-like molded product under the above cooling conditions. Good.
  • the bonding together it is necessary to laminate
  • the polyolefin resin solution laminated and extruded from the die may be formed as a laminated gel-like molded product under the above cooling conditions.
  • the laminated polyolefin is a porous laminate comprising at least an A layer and a B layer.
  • the layer configuration of the laminated polyolefin may be at least two layers of the A layer and the B layer from the viewpoint of physical properties balance such as shutdown characteristics and strength and permeability, but from the viewpoint of the front and back balance of the final film, A three-layer structure of A layer / B layer / A layer or B layer / A layer / B layer is more preferable.
  • the protrusions may be formed on either the A layer or the B layer, but from the viewpoint of the balance between permeability and strength, the surface layer is the A layer,
  • the inner layer is preferably a B layer.
  • the surface layer is B and the inner layer is A.
  • the thickness of layer B of the laminated polyolefin microporous membrane is preferably 3 ⁇ m or more and 15 ⁇ m or less.
  • the upper limit is more preferably 10 ⁇ m, further preferably 7 ⁇ m, and further preferably 6 ⁇ m.
  • the lower limit is preferably 4 ⁇ m.
  • the thickness of the B layer refers to the total thickness of each B layer when the laminated polyolefin microporous membrane has two or more B layers.
  • the laminated gel-like molded product is stretched to obtain a stretched molded product. Stretching is performed by heating the gel-like molded product and performing normal tenter method, roll method, or a combination of these methods at a predetermined magnification in two directions of MD and TD.
  • the stretching may be either simultaneous stretching (simultaneous biaxial stretching) or sequential stretching in MD and TD (machine direction and width direction). In the sequential stretching, the order of MD and TD is not limited, and at least one of MD and TD may be stretched in multiple stages.
  • the draw ratio varies depending on the thickness of the original fabric, but is preferably 9 times or more, more preferably 16 to 400 times in terms of surface magnification.
  • stretching at the same magnification of MD and TD such as 3 ⁇ 3, 5 ⁇ 5, or 7 ⁇ 7 is preferable.
  • the surface magnification is in the above preferred range, stretching is sufficient and a highly elastic, high strength microporous membrane can be obtained.
  • a desired air resistance can be obtained by adjusting the stretching temperature.
  • the stretching temperature is preferably below the melting point of the polyolefin resin, and more preferably in the range of (polyolefin resin crystal dispersion temperature Tcd) to (polyolefin resin melting point).
  • Tcd polyolefin resin crystal dispersion temperature
  • the crystal dispersion temperature Tcd is determined from the temperature characteristics of dynamic viscoelasticity measured according to ASTM D 4065. Or it may obtain
  • (E) A step of extracting and removing the molding solvent from the laminated stretched molded product and drying to obtain a laminated porous molded product.
  • the stretched molded product is treated with a washing solvent to remove the remaining molding solvent, A porous membrane is obtained.
  • Cleaning solvents include hydrocarbons such as pentane, hexane and heptane, chlorinated hydrocarbons such as methylene chloride and carbon tetrachloride, fluorinated hydrocarbons such as ethane trifluoride, and ethers such as diethyl ether and dioxane. Volatile ones can be used. These cleaning solvents are appropriately selected according to the molding solvent used for dissolving the polyolefin, and are used alone or in combination.
  • the cleaning method can be performed by a method of immersing and extracting in a cleaning solvent, a method of showering the cleaning solvent, a method of sucking the cleaning solvent from the opposite side of the stretched molded product, or a method of a combination thereof. Washing as described above is performed until the residual solvent in the stretched molded product, which is a stretched molded product, is less than 1% by mass. Thereafter, the cleaning solvent is dried.
  • the cleaning solvent can be dried by heat drying, air drying, or the like.
  • (F) Step of heat-treating the laminated porous molded product to obtain a laminated polyolefin microporous membrane The laminated porous molded product obtained by drying is heat-treated to obtain a laminated polyolefin microporous membrane.
  • the heat treatment temperature is preferably 90 to 150 ° C. When the heat treatment temperature is in the above preferred range, the heat shrinkage rate of the obtained laminated polyolefin microporous membrane can be reduced, and the air resistance can be ensured.
  • the heat treatment time is not particularly limited, but it is usually preferably 1 second to 10 minutes, more preferably 3 seconds to 2 minutes. For the heat treatment, any of a tenter method, a roll method, a rolling method, and a free method can be adopted.
  • the heat treatment step it is preferable to grip in both the MD (machine direction) and TD (width direction) directions and contract in at least one direction of MD and TD.
  • the contraction rate for contracting in at least one direction of MD and TD is preferably 0.01 to 50%, more preferably 3 to 20%.
  • the shrinkage rate is within the above preferable range, the thermal shrinkage rate at 105 ° C. and 8 hours is improved, and the air resistance is maintained.
  • TD or MD may be further performed before the heat treatment, or redrawing of about 5% to 20% in both directions may be performed.
  • the microporous membrane may be hydrophilized.
  • the hydrophilic treatment can be performed by monomer grafting, surfactant treatment, corona discharge or the like. Monomer grafting is preferably performed after the crosslinking treatment.
  • the corona discharge treatment can be performed in air, nitrogen, or a mixed atmosphere of carbon dioxide and nitrogen.
  • the modified porous layer used in the present invention is preferably laminated on the side having the protrusions of the laminated polyolefin microporous membrane.
  • the modified porous layer is provided on both sides of the laminated polyolefin microporous membrane, the modified porous layer on the side to which the parallel stress is more strongly applied by the contact of a roll or a bar in the subsequent process such as the slitting process or the conveying process.
  • Lamination is preferably performed on the side of the laminated polyolefin microporous membrane having the protrusions because the effect of the present invention is exhibited.
  • the modified porous layer referred to in the present invention imparts or improves at least one function such as heat resistance, adhesion to an electrode material, and electrolyte permeability.
  • the modified porous layer contains inorganic particles and a binder having a tensile strength of 5 N / mm 2 or more.
  • a binder having a tensile strength of 5 N / mm 2 or more By using a binder having a tensile strength of 5 N / mm 2 or more, a battery separator having an extremely excellent 0 ° peel strength can be obtained by the synergistic effect of the protrusions present on the surface of the laminated polyolefin microporous membrane and the tensile strength of the binder. .
  • the battery separator does not significantly increase the air resistance as compared with the case of the laminated polyolefin microporous membrane alone. This is because sufficient 0 ° peel strength can be obtained without allowing a large amount of binder to penetrate into the pores of the laminated polyolefin microporous membrane.
  • Tensile strength of the binder is at 5N / mm 2 or more, the lower limit is preferably 10 N / mm 2, more preferably 20 N / mm 2, more preferably 30 N / mm 2. There is no particular upper limit, but 100 N / mm 2 is sufficient.
  • the tensile strength of the binder refers to a value measured by the method described later.
  • the use tensile strength of 5N / mm 2 or more binders in the present invention although the tensile strength is not particularly limited as long as 5N / mm 2 or more, e.g., polyvinyl alcohol, cellulose ether resins, and acrylic resins .
  • the cellulose ether resin include carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), carboxyethyl cellulose, methyl cellulose, ethyl cellulose, cyanethyl cellulose, oxyethyl cellulose and the like.
  • the acrylic resin a cross-linked acrylic resin is preferable. Commercially available aqueous solutions or aqueous dispersions can also be used.
  • Examples of commercially available products include “POVACOAT” (registered trademark) manufactured by Nisshin Kasei Co., Ltd., “Jurimer” (registered trademark) AT-510, ET-410, FC-60 manufactured by Toa Gosei Co., Ltd.
  • Examples include SEK-301, UW-223SX, UW-550CS manufactured by Taisei Fine Chemical Co., Ltd., WE-301, EC-906EF, CG-8490 manufactured by DIC Corporation.
  • polyvinyl alcohol and acrylic resins having electrode adhesion, high affinity with non-aqueous electrolytes, suitable heat resistance, and relatively high tensile strength are preferable.
  • the coating liquid for forming the modified porous layer contains inorganic particles.
  • the coating liquid in this specification contains a binder having a tensile strength of 5 N / mm 2 or more, inorganic particles, and a solvent capable of dissolving or dispersing the binder, and is used for forming a modified porous layer.
  • the binder has at least a role of bonding inorganic particles and a role of bonding the laminated polyolefin microporous membrane and the modified porous layer.
  • the solvent include water, alcohols, acetone, and n-methylpyrrolidone.
  • the effect of preventing internal short circuit (dendrite prevention effect) due to the growth of the dendritic crystals of the electrode inside the battery, the effect of reducing the heat shrinkage, and the provision of slipperiness are also obtained. be able to.
  • the upper limit of the amount of added particles is preferably 98% by mass, more preferably 95% by mass.
  • the lower limit is preferably 80% by mass, and more preferably 85% by mass.
  • the average particle size of the inorganic particles is preferably 1.5 times or more and 50 times or less, more preferably 2.0 times or more and 20 times or less of the average pore size of the laminated polyolefin microporous membrane.
  • the average particle diameter of the particles is within the above-mentioned preferable range, an increase in the air resistance due to blocking the pores of the laminated polyolefin microporous film in a state where the heat-resistant resin and the particles are mixed is prevented, and further, the battery This prevents the particles from falling off during the assembly process, leading to serious battery defects.
  • Inorganic particles include calcium carbonate, calcium phosphate, amorphous silica, crystalline glass filler, kaolin, talc, titanium dioxide, alumina, silica-alumina composite oxide particles, barium sulfate, calcium fluoride, lithium fluoride, zeolite , Molybdenum sulfide, mica, boehmite and the like.
  • the heat-resistant crosslinked polymer particles include crosslinked polystyrene particles, crosslinked acrylic resin particles, and crosslinked methyl methacrylate particles.
  • Examples of the shape of the inorganic particles include a true spherical shape, a substantially spherical shape, a plate shape, a needle shape, and a polyhedral shape, but are not particularly limited.
  • the solid content concentration of the coating solution is not particularly limited as long as it can be uniformly applied, but is preferably 50% by mass or more and 98% by mass or less, and more preferably 80% by mass or more and 95% by mass or less.
  • the solid content concentration of the coating solution is in the above preferred range, the modified porous layer is prevented from becoming brittle, and a sufficient peel strength of 0 ° of the modified porous layer can be obtained.
  • the film thickness of the modified porous layer is preferably 1 to 5 ⁇ m, more preferably 1 to 4 ⁇ m, and still more preferably 1 to 3 ⁇ m.
  • the battery separator obtained by laminating the modified porous layer can ensure the film breaking strength and insulation when melted / shrinked at the melting point or higher, and A sufficient pore blocking function can be obtained and abnormal reactions can be prevented.
  • the winding volume can be suppressed, which is suitable for increasing the battery capacity. In addition, suppressing curling leads to improved productivity in the battery assembly process.
  • the porosity of the modified porous layer is preferably 30 to 90%, more preferably 40 to 70%.
  • the desired porosity can be obtained by appropriately adjusting the concentration of inorganic particles, the binder concentration, and the like.
  • the battery separator obtained by laminating the modified porous layer has a low electrical resistance of the membrane, a large current flows easily, and the membrane strength is maintained.
  • the upper limit of the total film thickness of the battery separator obtained by laminating the modified porous layer is preferably 25 ⁇ m, more preferably 20 ⁇ m.
  • the lower limit is preferably 6 ⁇ m or more, more preferably 7 ⁇ m or more.
  • the air resistance of the battery separator is one of the most important characteristics, and is preferably 50 to 400 sec / 100 cc Air, more preferably 100 to 350 sec / 100 cc Air, and further preferably 100 to 300 sec / 100 cc Air.
  • the desired air resistance can be obtained by adjusting the porosity of the modified porous layer and adjusting the degree of penetration of the binder into the laminated polyolefin microporous membrane.
  • the air permeability resistance of the battery separator is within the above preferable range, sufficient insulation is obtained, and foreign matter clogging, short circuit and film breakage are prevented. Further, by suppressing the film resistance, charge / discharge characteristics and life characteristics within a practically usable range can be obtained.
  • the method for laminating the modified porous layer on the laminated polyolefin microporous membrane of the present invention comprises the following step (g).
  • (G) A coating liquid containing a binder having a tensile strength of 5 N / mm 2 or more, an inorganic particle, and a solvent capable of dissolving or dispersing the binder on the surface of the laminated polyolefin microporous film in contact with the cooling roll. The process of forming a laminated film and drying.
  • the coating solution is applied to the laminated polyolefin microporous film by a method described later so as to have a predetermined film thickness, and the drying temperature is 40 to 80 ° C. and the drying time is 5 seconds to 60 seconds. It can be obtained by a drying method.
  • a coating solution in which the binder is soluble and dissolved in a solvent miscible with water is laminated on a predetermined laminated polyolefin microporous film using a coating method described later, and is placed in a specific humidity environment. It is also possible to use a method in which the solvent to be mixed is phase-separated and the binder is further solidified by adding it to a water bath (coagulation bath).
  • Examples of methods for applying the coating liquid include reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, Mayer bar coating method, pipe doctor method, blade coating. Method, die coating method and the like, and these methods can be carried out singly or in combination.
  • the battery separator of the present invention is desirably stored in a dry state, but when it is difficult to store in a completely dry state, it is preferable to perform a vacuum drying treatment at 100 ° C. or lower immediately before use.
  • the battery separator of the present invention includes a nickel-hydrogen battery, a nickel-cadmium battery, a nickel-zinc battery, a silver-zinc battery, a secondary battery such as a lithium secondary battery, a lithium polymer secondary battery, and a plastic film capacitor, ceramic Although it can be used as a separator for a capacitor, an electric double layer capacitor, etc., it is particularly preferably used as a separator for a lithium ion secondary battery.
  • a lithium ion secondary battery will be described as an example.
  • a positive electrode and a negative electrode are laminated via a separator, and the separator contains an electrolytic solution (electrolyte).
  • the structure of the electrode is not particularly limited, and may be a known structure.
  • the positive electrode usually has a current collector and a positive electrode active material layer containing a positive electrode active material capable of occluding and releasing lithium ions formed on the surface of the current collector.
  • the positive electrode active material include transition metal oxides, composite oxides of lithium and transition metals (lithium composite oxides), inorganic compounds such as transition metal sulfides, and the like.
  • the transition metal include V, Mn, Fe, Co, and Ni.
  • Preferred examples of the lithium composite oxide among the positive electrode active materials include lithium nickelate, lithium cobaltate, lithium manganate, and a layered lithium composite oxide based on an ⁇ -NaFeO 2 type structure.
  • the negative electrode has a current collector and a negative electrode active material layer including a negative electrode active material formed on the surface of the current collector.
  • the negative electrode active material include carbonaceous materials such as natural graphite, artificial graphite, cokes, and carbon black.
  • the electrolytic solution can be obtained by dissolving a lithium salt in an organic solvent.
  • Lithium salts include LiClO 4 , LiPF 6 , LiAsF 6 , LiSbF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , Li 2 B 10 Cl 10 , Examples include LiN (C 2 F 5 SO 2 ) 2 , LiPF 4 (CF 3 ) 2 , LiPF 3 (C 2 F 5 ) 3 , lower aliphatic carboxylic acid lithium salt, LiAlCl 4 and the like. These may be used alone or in admixture of two or more.
  • organic solvent examples include high boiling point and high dielectric constant organic solvents such as ethylene carbonate, propylene carbonate, ethyl methyl carbonate, and ⁇ -butyrolactone, and tetrahydrofuran, 2-methyltetrahydrofuran, dimethoxyethane, dioxolane, dimethyl carbonate, diethyl carbonate, and the like.
  • organic solvents having a low boiling point and a low viscosity These may be used alone or in admixture of two or more.
  • a high dielectric constant organic solvent has a high viscosity
  • a low viscosity organic solvent has a low dielectric constant. Therefore, it is preferable to use a mixture of both.
  • the separator of the present invention can be impregnated with an electrolytic solution to impart ion permeability to the separator.
  • the impregnation treatment is performed by immersing the microporous membrane in an electrolytic solution at room temperature.
  • a battery can be obtained by inserting this electrode element into a battery can, impregnating with the above electrolyte, and caulking a battery lid also serving as a positive electrode terminal provided with a safety valve via a gasket.
  • the measured value in an Example is a value measured with the following method.
  • protrusions The number and size of protrusions were measured after stabilizing the light source using a confocal microscope (HD100 manufactured by Lasertec Corporation) placed on a base isolation table.
  • a confocal microscope HD100 manufactured by Lasertec Corporation
  • a 1 cm ⁇ 1 cm square frame was drawn with an ultrafine oil pen on the surface of the laminated polyolefin microporous membrane obtained in Examples and Comparative Examples that was in contact with a cooling roll during film formation.
  • the surface on which the square frame was drawn was placed on the sample stage, and was fixed to the sample stage using an electrostatic contact apparatus attached to the confocal microscope.
  • a ring-shaped trace derived from a polyolefin spherulite as shown in FIG. 3 is displayed on a monitor as a two-dimensional image (referred to as a REAL screen in this apparatus).
  • the position of the sample stage was adjusted so that the darkest part of was positioned almost at the center of the monitor screen.
  • the object of the projection height measurement was such that the major axis of the ring-shaped mark derived from the polyolefin spherulites was 0.2 mm or more.
  • the cursor was placed on both ends of the ring in the major axis direction in the two-dimensional image, and the length was read.
  • REFSET This device is referred to as REFSET.
  • the measurement range in the height direction was set to 15 ⁇ m above and below, with the reference height being 0 ⁇ m. Also, the scan time was 120 seconds, the STEP moving distance was 0.1 ⁇ m / Step, and the three-dimensional data was captured.
  • a data processing image (referred to as a Z image in the present apparatus) was displayed and smoothing processing was performed (smoothing condition: filter size 3 ⁇ 3, matrix type SMOOTH3-0, once). In addition, horizontal correction was performed on the horizontal correction screen as necessary.
  • a cursor was placed in a horizontal direction at a position (the brightest part) passing through the highest protrusion in the data processing image, and a cross-sectional profile corresponding to the cursor was displayed on the cross-sectional profile image.
  • the two cursors were aligned with the inflection points of the sleeves of the protrusions in the vertical direction, and the distance between the cursors was taken as the protrusion size.
  • FIG. 1 schematically shows the evaluation method.
  • 1 is a laminated sample
  • 2 is a laminated polyolefin microporous membrane
  • 3 is a modified porous layer
  • 4 is a double-sided pressure-sensitive adhesive tape
  • a double-sided adhesive tape (NW-K50 manufactured by Nichiban Co., Ltd.) 4 having the same size was attached to an aluminum plate 5 having a size of 50 mm ⁇ 25 mm and a thickness of 0.5 mm.
  • the surface of the laminated polyolefin microporous membrane 2 of Sample 1 (battery separator) cut out to a width of 50 mm and a length of 100 mm is pasted on the aluminum plate 5 so that 40 mm overlaps from the edge of one side of the 25 mm length. Attached and cut off the protruding part. Next, a double-sided adhesive tape is attached to one side of an aluminum plate 5 ′ having a length of 100 mm, a width of 15 mm, and a thickness of 0.5 mm, so that 20 mm overlaps from the end of one side of the 25 mm long sample side of the aluminum plate 5. Pasted on.
  • the aluminum plate 5 and the aluminum plate 5 ′ sandwiching the sample are attached to a tensile testing machine (Autograph AGS-J load cell capacity 1 kN, manufactured by Shimadzu Corporation), and the aluminum plate 5 and the aluminum plate 5 ′ are opposite in parallel.
  • the film was pulled in the direction at a pulling speed of 10 mm / min, and the strength when the modified porous layer was peeled was measured. This measurement was performed for three arbitrary points spaced 30 cm or more in the longitudinal direction, and the average value was defined as 0 ° peel strength of the modified porous layer.
  • Average pore diameter The average pore diameter of the laminated polyolefin microporous membrane was measured by the following method. The sample was fixed on the measurement cell using double-sided tape, platinum or gold was vacuum-deposited for several minutes, and the surface of the film was subjected to SEM measurement at an appropriate magnification. Arbitrary ten places were selected on the image obtained by SEM measurement, and the average value of the pore diameters at these ten places was taken as the average pore diameter of the sample.
  • Air permeability resistance (sec / 100ccAir) Using a Gurley Densometer Type B manufactured by Tester Sangyo Co., Ltd., fix the laminated polyolefin microporous membrane or battery separator so that there are no wrinkles between the clamping plate and the adapter plate, and in accordance with JIS P8117 It was measured.
  • the sample was a 10 cm square, the measurement points were a total of 5 points at the center and 4 corners of the sample, and the average value was used as the air resistance. When the length of one side of the sample is less than 10 cm, a value obtained by measuring five points at intervals of 5 cm may be used.
  • the increase width of the air permeability resistance was obtained from the following formula.
  • meltdown temperature Using a thermomechanical analyzer (Seiko Denshi Kogyo Co., Ltd., TMA / SS6000), pulling a 10 mm (TD) ⁇ 3 mm (MD) test piece in the longitudinal direction of the test piece with a constant load of 2 gf The temperature at which the temperature was raised from room temperature at a rate of 5 ° C./min and the film was broken by melting was taken as the meltdown temperature.
  • a linear baseline is set in the range of 85 to 175 ° C, and the calorific value is calculated from the area surrounded by the linear baseline and the DSC curve. Converted per sample mass.
  • the evaluation area was 100 mm wide ⁇ 500 m long. (When the width was less than 100 mm, the length was adjusted so that the same evaluation area was obtained.) Judgment criteria ⁇ (very good): 5 or less ⁇ (good): 6 to 15 ⁇ (defect): 16 or more
  • Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) Mw and Mw / Mn were determined by gel permeation chromatography (GPC) method under the following conditions.
  • GPC gel permeation chromatography
  • ⁇ Measurement device GPC-150C manufactured by Waters Corporation Column: “Shodex” (registered trademark) UT806M manufactured by Showa Denko KK -Column temperature: 135 ° C
  • Injection volume 500 ⁇ l -Detector: Differential refractometer manufactured by Waters Corporation-Calibration curve: Prepared from a calibration curve obtained using a monodisperse polystyrene standard sample using a predetermined conversion constant.
  • Example 1 Tetrakis [methylene as an antioxidant was added to 100 parts by weight of a composition comprising 30% by weight of ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2 million and 70% by weight of high density polyethylene (HDPE) having a weight average molecular weight of 350,000.
  • UHMWPE ultra high molecular weight polyethylene
  • HDPE high density polyethylene
  • a polyethylene composition A to which 0.375 parts by weight of -3- (3,5-ditertiarybutyl-4-hydroxyphenyl) -propionate] methane was added was obtained. 30 parts by weight of this polyethylene composition A was charged into a twin screw extruder. 70 parts by weight of liquid paraffin was supplied from the side feeder of this twin screw extruder, melted and kneaded, and a polyolefin resin solution A was prepared in the extruder.
  • ultra high molecular weight polyethylene with a weight average molecular weight of 2 million is 15% by weight
  • high density polyethylene with a weight average molecular weight of 300,000 is 65% by weight
  • the weight average molecular weight is 530,000
  • the heat of fusion is 96 J /
  • a polyolefin composition B was obtained. 25 parts by weight of this polyolefin composition B was charged into a twin screw extruder. 75 parts by weight of liquid paraffin was supplied from the side feeder of this twin-screw extruder, melted and kneaded, and a polyolefin resin solution B was prepared in the extruder.
  • the obtained polyolefin resin solutions A and B were coextruded from a multilayer die at 190 ° C. so that the layer structure was A / B / A and the solution ratio was 1/1/1, and the internal cooling water temperature was 25 ° C.
  • a laminated gel-like molded product was formed while being taken up by a cooling roll having a diameter of 800 mm kept at the same temperature. At this time, one polyester doctor blade is inserted in the width direction of the gel-shaped molded article between the point where the laminated gel-shaped molded article is separated from the cooling roll and the point where the laminated polyethylene resin solution extruded from the die contacts the cooling roll.
  • a microporous membrane was obtained.
  • Polyvinyl alcohol (average polymerization degree 1700, saponification degree 99% or more), alumina particles having an average particle diameter of 0.5 ⁇ m, and ion-exchanged water were blended in a weight ratio of 6:54:40, respectively, and zirconium oxide beads (Toray Industries, Inc. ) “Traceram” (registered trademark) beads, 0.5 mm in diameter) and placed in a polypropylene container, and dispersed for 6 hours with a paint shaker (manufactured by Toyo Seiki Seisakusho). Subsequently, it filtered with the filter of 5 micrometers of filtration limits, and obtained the coating liquid (a).
  • a coating liquid (a) is applied by gravure coating to the surface of the laminated polyethylene microporous membrane that was in contact with the cooling roll during film formation, and dried by passing through a hot air drying oven at 50 ° C. for 10 seconds.
  • a battery separator having a final thickness of 22 ⁇ m was obtained.
  • Example 2 A battery separator was obtained in the same manner as in Example 1 except that two polyester doctor blades were applied to the cooling roll at an interval of 20 mm.
  • Example 3 A battery separator was obtained in the same manner as in Example 1 except that three polyester doctor blades were each applied to the cooling roll at an interval of 20 mm.
  • Example 4 Two-part curable aqueous acrylic urethane resin (solid content concentration 45% by mass) composed of aqueous acrylic polyol and water-dispersible polyisocyanate (curing agent), alumina particles having an average particle size of 0.5 ⁇ m, and ion-exchanged water are respectively 10:40: 50 weight ratio, zirconium oxide beads (Toraysemu "Traceram” (registered trademark) beads, diameter 0.5mm) together with polypropylene container, paint shaker (Toyo Seiki Seisakusho) For 6 hours. Subsequently, it filtered with the filter of 5 micrometers of filtration limits, and obtained the coating liquid (b). A modified porous layer was laminated in the same manner as in Example 1 except that the coating liquid (a) was changed to the coating liquid (b) to obtain a battery separator.
  • curing agent aqueous acrylic polyol and water-dispersible polyisocyanate
  • POVACOATR polyvinyl alcohol, acrylic acid and methyl methacrylate
  • Example 2 The solution was filtered through a filter having a filtration limit of 5 ⁇ m to obtain a coating solution (c).
  • a modified porous layer was laminated in the same manner as in Example 1 except that the coating liquid (a) was replaced with the coating liquid (c) to obtain a battery separator.
  • Example 6 A battery separator was obtained in the same manner as in Example 2 except that the internal cooling water temperature of the cooling roll was maintained at 35 ° C.
  • Example 7 As the polyolefin resin composition B, 5% by weight of ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2 million, 55% by weight of high density polyethylene (HDPE) having a weight average molecular weight of 300,000, and a weight average molecular weight of 530,000, A composition obtained by adding 0.375 parts by weight of an antioxidant to 100 parts by weight of a composition composed of 40% by weight of polypropylene having a heat of fusion of 96 J / g and 70 parts by weight of liquid paraffin with respect to 30 parts by weight of polyethylene composition B A separator for a battery was obtained in the same manner as in Example 1 except that the polyolefin resin solution B was obtained by supplying the parts.
  • UHMWPE ultra high molecular weight polyethylene
  • HDPE high density polyethylene
  • Example 8 As polyolefin resin composition A, 100 parts by weight of a composition comprising 20% by weight of ultrahigh molecular weight polyethylene (UHMWPE) having a weight average molecular weight of 2 million and 80% by weight of high density polyethylene (HDPE) having a weight average molecular weight of 300,000, The same procedure as in Example 1 was conducted except that a composition to which 0.375 parts by weight of antioxidant was added and 70 parts by weight of liquid paraffin was supplied to 30 parts by weight of polyethylene composition B to obtain polyolefin resin solution B. Thus, a battery separator was obtained.
  • UHMWPE ultrahigh molecular weight polyethylene
  • HDPE high density polyethylene
  • Example 9 A battery separator was obtained in the same manner as in Example 3 except that the extrusion amounts of the polyolefin solutions A and B were adjusted so that the thickness of the polyolefin laminated porous membrane was as shown in the table.
  • Example 10 Except for blending ratio of ultrahigh molecular weight polyethylene and high density polyethylene of polyolefin composition A, and not using ultrahigh molecular weight polyethylene for polyolefin composition B, except that the blending ratio of high density polyethylene and polypropylene is as shown in the table.
  • a battery separator was obtained in the same manner as in Example 1.
  • Example 11 Alumina particles are replaced with crosslinked polymer particles (polymethyl methacrylate-based crosslinked product particles (“Eposter” (registered trademark) MA1002, manufactured by Nippon Shokubai Co., Ltd., average particle size: 2.5 ⁇ m)).
  • Varnish (d) was obtained with a blending ratio of -methyl-2-pyrrolidone of 35:10:55 (weight ratio).
  • a battery separator was obtained in the same manner as in Example 1 except that the varnish (d) was used.
  • Example 12 Fluorine resin solution (“KF polymer” (registered trademark) # 9300 (polyvinylidene fluoride (5% N-methylpyrrolidone solution) manufactured by Kureha Chemical Industry Co., Ltd.) and alumina particles having an average particle size of 0.5 ⁇ m, N-methyl- 2-pyrrolidone was blended at a weight ratio of 16:34:50, respectively, and placed in a polypropylene container together with zirconium oxide beads (“Traceram” (registered trademark) beads, diameter 0.5 mm) manufactured by Toray Industries, Inc.
  • KF polymer registered trademark
  • # 9300 polyvinylidene fluoride (5% N-methylpyrrolidone solution) manufactured by Kureha Chemical Industry Co., Ltd.
  • alumina particles having an average particle size of 0.5 ⁇ m N-methyl- 2-pyrrolidone
  • the mixture was dispersed with a shaker (manufactured by Toyo Seiki Seisakusho Co., Ltd.) for 6 hours, and then filtered through a filter with a filtration limit of 5 ⁇ m to obtain varnish (e), which was the same as Example 1 except that varnish (e) was used. Thus, a battery separator was obtained.
  • Example 13 Acrylic emulsion (“Polysol” (registered trademark) AT-731 manufactured by Showa Denko KK, nonvolatile content 47%), alumina particles having an average particle size of 0.5 ⁇ m, and ion-exchanged water in a weight ratio of 2:55:43, respectively.
  • Polysol registered trademark
  • alumina particles having an average particle size of 0.5 ⁇ m
  • ion-exchanged water in a weight ratio of 2:55:43, respectively.
  • zirconium oxide beads Toraysemu "Traceram” (registered trademark) beads, diameter 0.5mm
  • Toyo Seiki Seisakusho Toyo Seiki Seisakusho
  • Example 14 A battery separator was obtained in the same manner as in Example 1 except that the coating liquid (g) in which the alumina particles were changed to barium sulfate fine particles (average particle size: 0.3 ⁇ m) was used.
  • Comparative Example 1 Except that only the polyethylene solution A was used to extrude from a single-layer die at 190 ° C. to form a single-layer gel-like molding, and the single-layer gel-like molding obtained instead of the laminated gel-like molding was used. A battery separator was obtained in the same manner as in Example 1.
  • Comparative Example 2 A battery separator was obtained in the same manner as in Example 8 except that a polypropylene having a weight average molecular weight of 490,000 and a heat of fusion of 70 J / g was used as the polypropylene used for the polyolefin solution B.
  • Comparative Example 3 As the polyolefin resin compositions A and B, battery separators were obtained in the same manner as in Example 1 except that the blending ratio, addition amount, and resin concentration were as shown in the table.
  • Comparative Example 4 The polyethylene resin solution extruded from the die was cooled with a cooling roll, and when the gel-like molded product was obtained, the doctor blade was not used and the liquid paraffin adhering to the cooling roll was not scraped off. Similarly, a battery separator was obtained.
  • Comparative Example 5 A battery separator was obtained in the same manner as in Example 1 except that the internal cooling water temperature of the cooling roll was kept at 0 ° C. and the doctor blade was not used.
  • Comparative Example 6 Instead of cooling the polyethylene resin solution extruded from the die with a cooling roll, a battery separator was obtained in the same manner as in Example 1 except that the polyethylene resin solution was immersed in water kept at 25 ° C. for 1 minute.
  • Comparative Example 7 A battery separator was obtained in the same manner as in Example 1 except that the internal cooling water temperature of the cooling roll was kept at 50 ° C.
  • a polyamide-imide resin solution, alumina particles having an average particle size of 0.5 ⁇ m, and N-methyl-2-pyrrolidone were blended in a weight ratio of 26:34:40, respectively, and zirconium oxide beads (“Traceram” manufactured by Toray Industries, Inc. (registered) (Trademark) beads, 0.5 mm in diameter) were placed in a polypropylene container and dispersed for 6 hours with a paint shaker (Toyo Seiki Seisakusho). Subsequently, it filtered with the filter of 5 micrometers of filtration limits, and obtained the coating liquid (h). The coating liquid (h) was applied to the laminated polyethylene microporous membrane obtained in the same manner as in Example 1 by the gravure coating method in the same manner as in Example 1 to obtain a battery separator.
  • zirconium oxide beads (“Traceram” manufactured by Toray Industries, Inc. (registered) (Trademark) beads, 0.5 mm in diameter) were placed in a polypropylene
  • Table 1 shows the production conditions of Examples 1 to 14 and Comparative Examples 1 to 8.
  • Table 2 shows the characteristics of the obtained laminated polyolefin microporous membrane and battery separator.

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Abstract

L'invention fournit un séparateur pour batterie qui à supposer que l'amincissement des films et la réduction du coût des séparateurs se poursuivent dans le futur, présente une résistance au pelage vis-à-vis d'une couche poreuse modifiée extrêmement élevée, est adapté à un usinage rapide lors d'une étape de refendage ou une étape d'assemblage de batterie, se révèle excellent en termes de caractéristiques de fusion, et est adapté à une batterie au lithium-ion. Plus précisément, l'invention concerne un séparateur pour batterie qui possède un film microporeux de polyoléfine stratifié, et la couche poreuse modifiée qui est présente sur au moins une des faces de ce dernier. Ledit film microporeux de polyoléfine stratifié consiste en un corps stratifié poreux contenant au moins une couche A et une couche B, présente une température de fusion supérieure ou égale à 165°C et une résistance à la perméabilité à l'air de 300sec/100ccAir, et présente de manière irrégulière des saillies constituées de polyoléfine à raison d'au moins 3/cm2 et d'au plus 200/cm2 sur au moins une des surfaces en vis-à-vis avec l'extérieur. Lesdites saillies satisfont 0,5µm≤H (H représentant la hauteur des saillies) et 5µm≤W≤50µm (W représentant la grosseur des saillies). Ladite couche poreuse modifiée est stratifiée sur la face dudit film microporeux de polyoléfine stratifié possédant les saillies. Le séparateur pour batterie de l'invention contient un liant d'une résistance à la traction supérieure ou égale à 5N/mm2, et des particules inorganiques.
PCT/JP2015/064696 2014-06-11 2015-05-22 Séparateur pour batterie, et procédé de fabrication ce celui-ci WO2015190265A1 (fr)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3340343A1 (fr) 2016-12-20 2018-06-27 Asahi Kasei Kabushiki Kaisha Séparateur de dispositif de stockage d'énergie et corps stratifié, rouleau et batterie secondaire l'utilisant
KR20180071961A (ko) 2016-12-20 2018-06-28 아사히 가세이 가부시키가이샤 축전 디바이스용 세퍼레이터, 및 이를 사용한 적층체, 권회체 및 이차 전지
EP3392931A4 (fr) * 2016-08-26 2019-02-06 LG Chem, Ltd. Séparateur pour dispositif électrochimique et dispositif électrochimique comprenant ledit séparateur
JP2019516206A (ja) * 2016-03-23 2019-06-13 シャンハイ、エナジー、ニュー、マテリアルズ、テクノロジー、カンパニー、リミテッドＳｈａｎｇｈａｉ Ｅｎｅｒｇｙ Ｎｅｗ Ｍａｔｅｒｉａｌｓ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．， Ｌｔｄ． 電気化学的装置用セパレータおよびその調製方法および使用
WO2020189119A1 (fr) * 2019-03-19 2020-09-24 帝人株式会社 Séparateur pour cellule secondaire non aqueuse, et cellule secondaire non aqueuse
CN114243221A (zh) * 2021-12-23 2022-03-25 中材锂膜有限公司 高弹性形变量隔膜及其制备方法

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107200901A (zh) * 2017-05-15 2017-09-26 上海恩捷新材料科技股份有限公司 形成电池隔离膜的聚合物组合物、电池隔离膜及制备方法
KR102295081B1 (ko) * 2017-11-17 2021-08-27 주식회사 엘지에너지솔루션 접착력 측정방법
KR102168816B1 (ko) * 2017-12-11 2020-10-22 도레이배터리세퍼레이터필름 한국유한회사 수계 코팅 조성물 및 이를 사용한 세퍼레이터
CN115810870A (zh) 2018-10-11 2023-03-17 旭化成株式会社 使用交联分隔件的锂离子电池
KR102409258B1 (ko) * 2018-10-11 2022-06-15 아사히 가세이 가부시키가이샤 리튬 이온 전지용 세퍼레이터
CN113474155B (zh) * 2018-12-06 2023-07-11 凸版印刷株式会社 阻气性膜
JP6796744B1 (ja) * 2019-03-29 2020-12-09 リンテック株式会社 接合方法
CN113999420B (zh) * 2021-11-05 2022-11-25 衢州市闻天化工有限公司 一种建材的防水复合膜及其制备工艺

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010537845A (ja) * 2007-08-31 2010-12-09 東燃化学株式会社 ポリオレフィン多層微多孔膜、その製造方法、電池用セパレータ及び電池
JP2012076255A (ja) * 2010-09-30 2012-04-19 Mitsubishi Plastics Inc 積層多孔フィルム、非水電解液二次電池用セパレータ、および非水電解液二次電池
JP2012521914A (ja) * 2009-03-30 2012-09-20 東レバッテリーセパレータフィルム株式会社 微多孔性ポリマー膜、電池用セパレータ、およびそれらの製造方法
WO2013146585A1 (fr) * 2012-03-30 2013-10-03 東レバッテリーセパレータフィルム株式会社 Membrane microporeuse en polyéthylène et son procédé de fabrication
WO2013165151A1 (fr) * 2012-04-30 2013-11-07 주식회사 엘지화학 Séparateur et dispositif électrochimique le comprenant
WO2014132791A1 (fr) * 2013-02-27 2014-09-04 東レバッテリーセパレータフィルム株式会社 Film polyoléfine poreux, séparateur pour batterie l'utilisant, et leurs procédés de production

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10104988A1 (de) * 2001-02-03 2002-08-08 Varta Geraetebatterie Gmbh Verfahren zur Herstellung von Elektrodenfolien
CN101535386B (zh) * 2006-10-30 2012-07-04 旭化成电子材料株式会社 聚烯烃制微多孔膜
JP4931083B2 (ja) 2007-01-30 2012-05-16 旭化成イーマテリアルズ株式会社 多層多孔膜及びその製造方法
CN101779311B (zh) 2007-06-06 2013-11-20 帝人株式会社 非水系二次电池隔膜用聚烯烃微多孔膜基材、其制备方法、非水系二次电池隔膜和非水系二次电池
TW200919806A (en) 2007-06-06 2009-05-01 Asahi Kasei Chemicals Corp Multilayer porous film
JP5369602B2 (ja) 2008-10-22 2013-12-18 株式会社エクォス・リサーチ 車両
JP5323590B2 (ja) 2009-06-19 2013-10-23 旭化成イーマテリアルズ株式会社 多層多孔膜、樹脂製バインダおよび塗布液
JP5327540B2 (ja) 2009-09-28 2013-10-30 トヨタ自動車株式会社 リチウムイオン二次電池用セパレータおよびその製造方法
JP5495210B2 (ja) 2010-07-21 2014-05-21 東レバッテリーセパレータフィルム株式会社 複合多孔質膜、複合多孔質膜の製造方法並びにそれを用いた電池用セパレーター
CN104106155B (zh) * 2012-02-15 2017-03-01 东丽电池隔膜株式会社 电池用隔膜及电池用隔膜的制备方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010537845A (ja) * 2007-08-31 2010-12-09 東燃化学株式会社 ポリオレフィン多層微多孔膜、その製造方法、電池用セパレータ及び電池
JP2012521914A (ja) * 2009-03-30 2012-09-20 東レバッテリーセパレータフィルム株式会社 微多孔性ポリマー膜、電池用セパレータ、およびそれらの製造方法
JP2012076255A (ja) * 2010-09-30 2012-04-19 Mitsubishi Plastics Inc 積層多孔フィルム、非水電解液二次電池用セパレータ、および非水電解液二次電池
WO2013146585A1 (fr) * 2012-03-30 2013-10-03 東レバッテリーセパレータフィルム株式会社 Membrane microporeuse en polyéthylène et son procédé de fabrication
WO2013165151A1 (fr) * 2012-04-30 2013-11-07 주식회사 엘지화학 Séparateur et dispositif électrochimique le comprenant
WO2014132791A1 (fr) * 2013-02-27 2014-09-04 東レバッテリーセパレータフィルム株式会社 Film polyoléfine poreux, séparateur pour batterie l'utilisant, et leurs procédés de production

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019516206A (ja) * 2016-03-23 2019-06-13 シャンハイ、エナジー、ニュー、マテリアルズ、テクノロジー、カンパニー、リミテッドＳｈａｎｇｈａｉ Ｅｎｅｒｇｙ Ｎｅｗ Ｍａｔｅｒｉａｌｓ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．， Ｌｔｄ． 電気化学的装置用セパレータおよびその調製方法および使用
EP3392931A4 (fr) * 2016-08-26 2019-02-06 LG Chem, Ltd. Séparateur pour dispositif électrochimique et dispositif électrochimique comprenant ledit séparateur
US10978766B2 (en) 2016-08-26 2021-04-13 Lg Chem, Ltd. Separator for electrochemical device and electrochemical device including the same
EP3340343A1 (fr) 2016-12-20 2018-06-27 Asahi Kasei Kabushiki Kaisha Séparateur de dispositif de stockage d'énergie et corps stratifié, rouleau et batterie secondaire l'utilisant
KR20180071961A (ko) 2016-12-20 2018-06-28 아사히 가세이 가부시키가이샤 축전 디바이스용 세퍼레이터, 및 이를 사용한 적층체, 권회체 및 이차 전지
KR20200030045A (ko) 2016-12-20 2020-03-19 아사히 가세이 가부시키가이샤 축전 디바이스용 세퍼레이터, 및 이를 사용한 적층체, 권회체 및 이차 전지
WO2020189119A1 (fr) * 2019-03-19 2020-09-24 帝人株式会社 Séparateur pour cellule secondaire non aqueuse, et cellule secondaire non aqueuse
JP2020155248A (ja) * 2019-03-19 2020-09-24 帝人株式会社 非水系二次電池用セパレータ及び非水系二次電池
EP3920266A4 (fr) * 2019-03-19 2022-03-30 Teijin Limited Séparateur pour cellule secondaire non aqueuse, et cellule secondaire non aqueuse
JP7416522B2 (ja) 2019-03-19 2024-01-17 帝人株式会社 非水系二次電池用セパレータ及び非水系二次電池
CN114243221A (zh) * 2021-12-23 2022-03-25 中材锂膜有限公司 高弹性形变量隔膜及其制备方法
CN114243221B (zh) * 2021-12-23 2022-10-11 中材锂膜有限公司 高弹性形变量隔膜及其制备方法

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CN106415885A (zh) 2017-02-15
CN106415885B (zh) 2019-02-19

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