WO2017138512A1 - Polyolefin microporous membrane, separator film for power storage device, and power storage device - Google Patents
Polyolefin microporous membrane, separator film for power storage device, and power storage device Download PDFInfo
- Publication number
- WO2017138512A1 WO2017138512A1 PCT/JP2017/004356 JP2017004356W WO2017138512A1 WO 2017138512 A1 WO2017138512 A1 WO 2017138512A1 JP 2017004356 W JP2017004356 W JP 2017004356W WO 2017138512 A1 WO2017138512 A1 WO 2017138512A1
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- WIPO (PCT)
- Prior art keywords
- polyolefin microporous
- microporous membrane
- film
- heat
- storage device
- Prior art date
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- 150000002739 metals Chemical class 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- 239000012229 microporous material Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- VSIIXMUUUJUKCM-UHFFFAOYSA-D pentacalcium;fluoride;triphosphate Chemical compound [F-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O VSIIXMUUUJUKCM-UHFFFAOYSA-D 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 229920005673 polypropylene based resin Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- HNJBEVLQSNELDL-UHFFFAOYSA-N pyrrolidin-2-one Chemical compound O=C1CCCN1 HNJBEVLQSNELDL-UHFFFAOYSA-N 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 150000005687 symmetric chain carbonates Chemical class 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 230000003685 thermal hair damage Effects 0.000 description 1
- 229920006259 thermoplastic polyimide Polymers 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 150000003606 tin compounds Chemical class 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- 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
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
-
- 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
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/52—Separators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M50/491—Porosity
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- Patent Document 4 it is known that heat resistance is imparted by kneading a resin material having a high melting point with polyethylene or polypropylene resin material.
- the zero shear viscosity of the PP resin under the 200 ° C. condition is preferably in the range of 13000 to 20000 Pa ⁇ s.
- the meltdown temperature of the polyolefin microporous membrane can be at least 200 ° C. or higher.
- the zero shear viscosity of the PP resin is more preferably 14000 to 19000 Pa ⁇ s, and further preferably 15000 to 18000 Pa ⁇ s.
- the PP resin is preferably highly stereoregular.
- the pentad fraction of the PP resin is preferably 80% or more, and more preferably 90% or more.
- a PP-based resin and a PE-based resin which is a polyolefin microporous film.
- a PP-based resin and a PE-based resin are blended by kneading or the like to form a single layer film.
- stacked resin and PE resin is shown.
- laminated it may have a two-layer structure of PP / PE, a three-layer structure, or a laminated structure of four or more layers.
- Preferable forms are a single layer film of PP resin and a film having a three-layer structure.
- the total thickness of the polyolefin microporous membrane is preferably 7.0 ⁇ m or more, more preferably 7.5 ⁇ m or more, from the viewpoint of mechanical strength, performance, miniaturization, etc., as a power storage device separator. It is preferably 8.0 ⁇ m or more, and most preferably 8.5 ⁇ m or more.
- the upper limit is preferably 50 ⁇ m or less, more preferably 45 ⁇ m or less, and still more preferably 42 ⁇ m or less. If the film thickness is too thin, film breakage is likely to occur, the short circuit rate of the device is improved, and the safety may be lowered. On the other hand, if the film thickness is too thick, the safety when used as a separator for an electricity storage device is improved, but the ion conductivity is lowered and the rate characteristics of the device are lowered.
- the process for producing the above-mentioned polyolefin microporous membrane will be described below.
- the polyolefin microporous membrane of the present invention can be produced, for example, by going through three steps: a raw fabric (precursor film) production step, a lamination step, and a stretching step.
- the polyolefin microporous membrane can also be produced by producing an original fabric laminated in three layers using a two-type, three-layer multilayer original fabric forming apparatus, and then performing a stretching process.
- the heat-treated laminated film is stretched at a low temperature in a cold stretching zone and then stretched at a high temperature in a hot stretching zone to be made porous, thereby forming a laminated porous film.
- a polyolefin microporous membrane in which PP resin and PE resin are laminated the properties of polypropylene and polyethylene are not sufficiently made porous by only one of the stretching, and this is used as a battery separator. Becomes worse.
- the temperature of the low temperature stretching is preferably minus 20 ° C. or more and plus 50 ° C. or less, particularly preferably 20 ° C. or more and 40 ° C. or less. If this low temperature stretching temperature is too low, the film is likely to break during the operation, which is not preferable. On the other hand, if the low-temperature stretching temperature is too high, the porosity becomes insufficient, which is not preferable.
- the low-temperature stretching ratio (initial stretching ratio) is preferably in the range of 3% to 200%, more preferably in the range of 5% to 100%. When the low-temperature stretching ratio is too low, only a low porosity can be obtained. If it is too high, a product having a predetermined porosity and pore size cannot be obtained. Therefore, the above range is appropriate.
- the heat-treated film that has passed through the heat-stretching zone is then subjected to heat-fixing in which heat-treatment is performed in the heat-setting zone so that the dimensions in the stretching direction are not changed.
- the heat setting is performed under tension of a fixed length (0%) or more or 10% or less by a heated air circulation oven or a heating roll.
- the heat setting temperature is preferably 110 ° C. or more and 150 ° C. or less, and more preferably 115 ° C. or more and 140 ° C. or less.
- the temperature is low, a sufficient heat setting effect cannot be obtained, and the heat shrinkage rate of the polyolefin microporous membrane increases.
- the heat setting temperature is too high, the polyethylene is melted, which is inconvenient.
- the weight average molecular weight of the polypropylene resin (PP resin) contained in the polyolefin microporous membrane 10 shown in FIG. 3 is preferably 500,000 or more and 800,000 or less.
- the lower limit of the weight average molecular weight is more preferably 540,000 or more, and most preferably 550,000 or more.
- the upper limit of the weight average molecular weight is more preferably 750,000 or less, and most preferably 700,000 or less.
- the polyolefin microporous structure shown in FIG. 3 has a porosity of 40 to 70% and a surface opening ratio of 10 to 30% by the manufacturing method described later.
- the membrane 10 can be easily manufactured.
- the birefringence of the PP original fabric is preferably 15.0 ⁇ 10 ⁇ 3 to 17.0 ⁇ 10 ⁇ 3 .
- a polyolefin microporous film 10 having a porosity of 40 to 70% and a surface opening ratio of 10 to 30% is easily obtained, which is preferable.
- the elastic recovery rate of the PP original fabric is preferably 90% or less.
- the polyolefin microporous membrane 10 having a porosity of 40 to 70% and a surface opening ratio of 10 to 30% is easily obtained.
- the strength of the microporous membrane produced using the PP raw material becomes high, which is preferable.
- the separator film for an electricity storage device of the present invention has the polyolefin microporous film of the present invention.
- the separator film for an electricity storage device of one embodiment of the present invention can be composed of only the polyolefin microporous film of the present invention. That is, the polyolefin microporous membrane of the present invention can be used as it is as a separator film for an electricity storage device without any additional processing.
- Inorganic oxide fine particles such as aluminum nitride, silicon nitride, etc .; sparingly soluble ionic crystal fine particles such as calcium fluoride, barium fluoride, and barium sulfate; covalently bonded crystal fine particles such as silicon and diamond; montmorillonite Clay fine particles such as;
- the inorganic oxide fine particles may be fine particles such as boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, mica, or a mineral resource-derived material or an artificial product thereof.
- the inorganic compound which comprises these inorganic fine particles may be element-substituted, or may be made into a solid solution as needed.
- the inorganic fine particles may be subjected to a surface treatment.
- the inorganic fine particles are formed by electrically insulating the surface of a conductive material exemplified by metals, conductive oxides such as SnO 2 and tin-indium oxide (ITO), carbonaceous materials such as carbon black and graphite. It is also possible to use particles that are made electrically insulating by coating with a material having the above (for example, the above-mentioned inorganic oxide).
- heat-resistant fine particles those exemplified above may be used alone, or two or more kinds may be used in combination.
- heat-resistant fine particles inorganic fine particles and organic fine particles can be used as described above.
- boehmite is preferably used as the heat-resistant fine particles.
- boehmite having an average particle diameter of preferably 0.001 ⁇ m or more, more preferably 0.1 ⁇ m or more, preferably 15 ⁇ m or less, more preferably 3 ⁇ m or less is used.
- the heat-resistant porous layer is too thick, when used as a separator for an electricity storage device, the amount of electrolyte injected will increase, which will contribute to an increase in battery manufacturing cost, and the per unit volume and weight of the battery. This is not preferable because the energy density decreases.
- the method of forming the heat resistant porous layer includes a step of applying a coating liquid containing the heat resistant fine particles as a main component on one or both surfaces of the polyolefin microporous membrane, and drying the applied coating liquid to heat resistant porous Forming a layer.
- the organic solvent is not particularly limited as long as it is such, and for example, furans such as tetrahydrofuran (THF); ketones such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK);
- furans such as tetrahydrofuran (THF)
- ketones such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK)
- high boiling point organic solvents may damage the polyolefin microporous membrane by heat melting or the like when the organic solvent is removed by drying after applying the coating liquid for heat-resistant porous layer formation to the polyolefin microporous membrane.
- the separator used for electrical storage devices such as a lithium ion secondary battery and a lithium ion capacitor
- the shape of the separator may be appropriately adjusted according to, for example, the shape of the lithium ion secondary battery.
- the shapes of the positive electrode and the negative electrode may be appropriately adjusted according to the shape of the lithium ion secondary battery.
- a separator is comprised with the separator film for electrical storage devices of this embodiment, and has a single layer structure or a multilayer structure.
- the tensile strength in the MD direction and the TD direction was rounded to the nearest whole number by rounding off the first decimal place.
- the tensile elongation in the MD direction and the TD direction was rounded to an integer by rounding off the first decimal place.
- the average value of each measured value was evaluated as tensile strength and tensile elongation.
- Results were rounded to the first decimal place and summarized as an integer.
- the sample may be prepared by adjusting the film so that the film is placed in a circular hole having a central portion of ⁇ 40 mm.
- Example 4 As shown in Table 1, PP single-layer polyolefin microporous material was used in the same manner as in Example 8 except that a PP resin having a weight average molecular weight of 410,000, a molecular weight distribution of 9.3, and a melting point of 164 ° C. was used. A membrane was created. Tables 1 and 2 show the properties of the raw materials used and the physical properties and electrical properties of the obtained polyolefin microporous membrane.
- the polyolefin microporous membranes of Examples A to D have a meltdown temperature of 195 ° C. or more and 230 ° C. or less, and the result of the withstand voltage test is ⁇ , which is suitable as a separator for an electricity storage device. I was able to confirm.
- the polyolefin microporous membranes of Comparative Examples 5 and 6 had a meltdown temperature of less than 195 ° C. and had low safety when used as a separator for an electricity storage device.
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- Chemical Kinetics & Catalysis (AREA)
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- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Power Engineering (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
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Abstract
This polyolefin microporous membrane including a polypropylene resin has a meltdown temperature of 195-230ºC. The weight-average molecular weight of the polypropylene resin is preferably 500,000-800,000. Further, the molecular weight distribution of the polypropylene resin is preferably 7.5-16.
Description
本発明は、優れた耐熱性を示すポリオレフィン微多孔膜、それを有する蓄電デバイス用セパレータフィルム、及び蓄電デバイスに関する。
本出願は、２０１６年２月９日に日本に出願された特願２０１６－２２７９７、２０１６年１１月１５日に日本に出願された特願２０１６－２２２３６６に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a polyolefin microporous membrane exhibiting excellent heat resistance, a separator film for an electricity storage device having the same, and an electricity storage device.
This application claims priority based on Japanese Patent Application No. 2016-22797 filed in Japan on February 9, 2016 and Japanese Patent Application No. 2016-222366 filed in Japan on November 15, 2016. This is incorporated here.
本出願は、２０１６年２月９日に日本に出願された特願２０１６－２２７９７、２０１６年１１月１５日に日本に出願された特願２０１６－２２２３６６に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a polyolefin microporous membrane exhibiting excellent heat resistance, a separator film for an electricity storage device having the same, and an electricity storage device.
This application claims priority based on Japanese Patent Application No. 2016-22797 filed in Japan on February 9, 2016 and Japanese Patent Application No. 2016-222366 filed in Japan on November 15, 2016. This is incorporated here.
リチウムイオン二次電池やリチウムイオンキャパシタ等の蓄電デバイスでは、正負両極の短絡防止のために、正極と負極との間にポリオレフィン微多孔膜からなるセパレ－タフィルムが介在している。
近年、高エネルギー密度、高起電力、自己放電の少ない蓄電デバイス、特にリチウムイオン二次電池やリチウムイオンキャパシタ等が開発、実用化されるようになってきた。
リチウムイオン二次電池の負極としては、例えば金属リチウム、リチウムと他の金属との合金、カーボンやグラファイト等のリチウムイオンを吸着する能力又はインターカレーションにより吸蔵する能力を有する有機材料、リチウムイオンをドーピングした導電性高分子材料等が知られている。また、正極としては例えば（ＣＦｘ）ｎで示されるフッ化黒鉛、ＭｎＯ２、Ｖ２Ｏ５、ＣｕＯ、Ａｇ２ＣｒＯ４、ＴｉＯ２等の金属酸化物や硫化物、塩化物が知られている。 In power storage devices such as lithium ion secondary batteries and lithium ion capacitors, a separator film made of a polyolefin microporous film is interposed between the positive electrode and the negative electrode in order to prevent short circuit between the positive and negative electrodes.
In recent years, power storage devices with high energy density, high electromotive force, and low self-discharge, in particular lithium ion secondary batteries and lithium ion capacitors, have been developed and put into practical use.
Examples of the negative electrode of the lithium ion secondary battery include metallic lithium, an alloy of lithium and another metal, an organic material having the ability to adsorb lithium ions such as carbon and graphite, or the ability to occlude by intercalation, and lithium ions. Doped conductive polymer materials and the like are known. As the positive electrode, for example, fluorinated graphite represented by (CF x ) n , MnO 2 , V 2 O 5 , CuO, Ag 2 CrO 4 , TiO 2 and other metal oxides, sulfides, and chlorides are known. Yes.
近年、高エネルギー密度、高起電力、自己放電の少ない蓄電デバイス、特にリチウムイオン二次電池やリチウムイオンキャパシタ等が開発、実用化されるようになってきた。
リチウムイオン二次電池の負極としては、例えば金属リチウム、リチウムと他の金属との合金、カーボンやグラファイト等のリチウムイオンを吸着する能力又はインターカレーションにより吸蔵する能力を有する有機材料、リチウムイオンをドーピングした導電性高分子材料等が知られている。また、正極としては例えば（ＣＦｘ）ｎで示されるフッ化黒鉛、ＭｎＯ２、Ｖ２Ｏ５、ＣｕＯ、Ａｇ２ＣｒＯ４、ＴｉＯ２等の金属酸化物や硫化物、塩化物が知られている。 In power storage devices such as lithium ion secondary batteries and lithium ion capacitors, a separator film made of a polyolefin microporous film is interposed between the positive electrode and the negative electrode in order to prevent short circuit between the positive and negative electrodes.
In recent years, power storage devices with high energy density, high electromotive force, and low self-discharge, in particular lithium ion secondary batteries and lithium ion capacitors, have been developed and put into practical use.
Examples of the negative electrode of the lithium ion secondary battery include metallic lithium, an alloy of lithium and another metal, an organic material having the ability to adsorb lithium ions such as carbon and graphite, or the ability to occlude by intercalation, and lithium ions. Doped conductive polymer materials and the like are known. As the positive electrode, for example, fluorinated graphite represented by (CF x ) n , MnO 2 , V 2 O 5 , CuO, Ag 2 CrO 4 , TiO 2 and other metal oxides, sulfides, and chlorides are known. Yes.
また、非水電解液として、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ジエチルカーボネート（ＤＥＣ）、ジメチルカーボネート（ＤＭＣ）、γ－ブチロラクトン、アセトニトリル、１，２－ジメトキシエタン、テトラヒドロフラン等の有機溶媒にＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣｌＯ４、ＬｉＣＦ３ＳＯ３等の電解質を溶解したものが使用されている。
しかし、リチウムイオン二次電池では、リチウムの反応性が特に強いため、外部短絡や誤接続等により異常電流が流れた場合、電池温度が著しく上昇してこれを組み込んだ機器に熱的ダメージを与える懸念がある。このような危険性を回避するために、単層または積層のポリオレフィン微多孔膜が、リチウムイオン二次電池やリチウムイオンキャパシタ等の蓄電デバイス用のセパレータフィルムとして提案されている。 In addition, as non-aqueous electrolytes, organic solvents such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), γ-butyrolactone, acetonitrile, 1,2-dimethoxyethane, tetrahydrofuran, etc. In addition, an electrolyte such as LiPF 6 , LiBF 4 , LiClO 4 , LiCF 3 SO 3 or the like is used.
However, in lithium-ion secondary batteries, the reactivity of lithium is particularly strong, so if an abnormal current flows due to an external short circuit or incorrect connection, the battery temperature rises significantly, causing thermal damage to the device incorporating it. There are concerns. In order to avoid such danger, a single-layer or multi-layer polyolefin microporous film has been proposed as a separator film for power storage devices such as lithium ion secondary batteries and lithium ion capacitors.
しかし、リチウムイオン二次電池では、リチウムの反応性が特に強いため、外部短絡や誤接続等により異常電流が流れた場合、電池温度が著しく上昇してこれを組み込んだ機器に熱的ダメージを与える懸念がある。このような危険性を回避するために、単層または積層のポリオレフィン微多孔膜が、リチウムイオン二次電池やリチウムイオンキャパシタ等の蓄電デバイス用のセパレータフィルムとして提案されている。 In addition, as non-aqueous electrolytes, organic solvents such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), γ-butyrolactone, acetonitrile, 1,2-dimethoxyethane, tetrahydrofuran, etc. In addition, an electrolyte such as LiPF 6 , LiBF 4 , LiClO 4 , LiCF 3 SO 3 or the like is used.
However, in lithium-ion secondary batteries, the reactivity of lithium is particularly strong, so if an abnormal current flows due to an external short circuit or incorrect connection, the battery temperature rises significantly, causing thermal damage to the device incorporating it. There are concerns. In order to avoid such danger, a single-layer or multi-layer polyolefin microporous film has been proposed as a separator film for power storage devices such as lithium ion secondary batteries and lithium ion capacitors.
これらの単層又は積層のポリオレフィン微多孔膜を蓄電デバイス用セパレータフィルムとして使用することにより、両極間の短絡防止やデバイスの電圧の維持等を図ることができる。また、異常電流等でデバイスの内部温度が所定温度以上に上昇したときに、多孔膜の孔を塞いで無孔化させて、両極間にイオンが流れないように電気抵抗を増大させる。これにより蓄電デバイスの機能を停止させて、過度の温度上昇による発火等の危険を防止し、安全を確保することができる。過度の温度上昇による発火等の危険を防止する機能は、蓄電デバイス用のセパレータフィルムにとって極めて重要であり、一般に無孔化或いはシャットダウン（以下、ＳＤ）と呼ばれる。
By using these single-layer or multi-layer polyolefin microporous membranes as a separator film for an electricity storage device, it is possible to prevent a short circuit between both electrodes, maintain the device voltage, and the like. In addition, when the internal temperature of the device rises to a predetermined temperature or more due to an abnormal current or the like, the pores of the porous film are closed to make them non-porous, and the electrical resistance is increased so that ions do not flow between the two electrodes. Thereby, the function of the electricity storage device is stopped, the danger of ignition due to excessive temperature rise, etc. can be prevented, and safety can be ensured. The function of preventing dangers such as ignition due to excessive temperature rise is extremely important for a separator film for an electricity storage device, and is generally called non-porous or shutdown (hereinafter referred to as SD).
蓄電デバイス用のセパレ－タフィルムとしてポリオレフィン微多孔膜を用いた場合、無孔化開始温度が低すぎると、蓄電デバイスの僅かな温度上昇でイオンの流れが阻止されるため実用面で問題がある。また、無孔化開始温度が高すぎると、発火等を引き起こすまでイオンの流れを阻害できない危険性があり安全面で問題がある。一般に無孔化開始温度は１１０～１６０℃であり、好ましくは１２０～１５０℃であると考えられている。
When a polyolefin microporous film is used as a separator film for an electricity storage device, if the non-porous start temperature is too low, the flow of ions is blocked by a slight increase in temperature of the electricity storage device, which is problematic in practical use. . Further, if the non-porous start temperature is too high, there is a risk that the flow of ions cannot be inhibited until ignition or the like is caused. Generally, the non-porous start temperature is considered to be 110 to 160 ° C., preferably 120 to 150 ° C.
また、蓄電デバイス内の温度が無孔化維持上限温度を越えて上昇した場合、セパレータフィルムが溶断して破れが生じるメルトダウン（以下、ＭＤ）と呼ばれる現象により、再びイオンの移動が可能となり、更なる温度上昇が引き起こされる。このような理由から、蓄電デバイス用セパレ－タとして、適切な無孔化開始（ＳＤ）温度を有するだけでなく、無孔化を維持できる上限（ＭＤ）温度が高い、という特性が要求されている。さらに、セパレ－タフィルムに用いられるポリオレフィン微多孔膜としては、前記無孔化に関する特性の他に、電気抵抗が低いこと、引張強度等の機械的強度が高いこと、厚みムラや電気抵抗等のバラツキが小さいこと等が要求される。
In addition, when the temperature in the electricity storage device rises above the non-porous maintenance upper limit temperature, a phenomenon called meltdown (hereinafter referred to as MD) in which the separator film melts and breaks enables ion movement again, Further temperature rise is caused. For this reason, the electrical storage device separator is required not only to have a suitable non-porous start (SD) temperature, but also to have a high upper limit (MD) temperature at which non-porous can be maintained. Yes. Furthermore, the polyolefin microporous film used for the separator film has low electrical resistance, high mechanical strength such as tensile strength, thickness unevenness, electrical resistance, etc. A small variation is required.
蓄電デバイス用セパレータフィルムに用いられる単層又は積層された微多孔膜を製造する方法としては、様々な提案がなされている。特に多孔化の方法から大別すると、湿式法と乾式法に分類することができる（特許文献１、２参照）。
Various proposals have been made as a method for producing a single layer or a laminated microporous membrane used for a separator film for an electricity storage device. In particular, it can be roughly classified into a wet method and a dry method (see Patent Documents 1 and 2).
例えば特許文献１には、微多孔フィルムを製造する湿式法が開示されている。この製造方法は、微多孔フィルムを形成するマトリクス樹脂であるＰＥやＰＰ等の樹脂と、添加物とを添加・混合した樹脂を用いてフィルムを製膜する工程と；シート化した後に、マトリクス樹脂と添加物とからなるフィルムから添加物を抽出することで、マトリクス樹脂中に空隙を形成する工程と；その後、フィルムを延伸する工程とを含む。添加物としては、樹脂と混和する溶媒、可塑剤、無機微粒子などが提案されている。
For example, Patent Document 1 discloses a wet method for producing a microporous film. This manufacturing method includes a step of forming a film using a resin in which a resin such as PE or PP, which is a matrix resin for forming a microporous film, and an additive are added and mixed; And a step of forming voids in the matrix resin by extracting the additive from the film comprising the additive and a step of stretching the film. As additives, solvents, plasticizers, inorganic fine particles and the like that are miscible with the resin have been proposed.
微多孔フィルムの製造方法として湿式法を用いた場合、溶媒等の添加物を含有させることにより押出時の樹脂粘度を低下させることができる。そのため、多層膜の原料である高分子として、高分子量の原料を用いた製膜が可能となり、突き刺し強度や破断強度などの機械物性が向上させることが容易である。しかし、湿式法を用いた場合、溶媒の抽出工程に時間と労力を要し、生産性の向上が困難であった。
When a wet method is used as a method for producing a microporous film, the resin viscosity at the time of extrusion can be lowered by adding an additive such as a solvent. Therefore, it is possible to form a film using a high molecular weight raw material as a polymer that is a raw material of the multilayer film, and it is easy to improve mechanical properties such as piercing strength and breaking strength. However, when the wet method is used, time and labor are required for the solvent extraction process, and it is difficult to improve productivity.
また、湿式法で得られた微多孔膜の細孔径は比較的大きく、空孔率に対し透気度が低い傾向がある。このため、自動車用途のような高レートの充放電を行うとデンドライトが比較的容易に生成される等の問題があった。また、ＳＤ特性を向上させようとした場合にメルトダウン特性が低下する、もしくは調整が困難となる問題もあった。
Also, the microporous membrane obtained by the wet method has a relatively large pore diameter and tends to have a low air permeability relative to the porosity. For this reason, when charging and discharging at a high rate as in automobile applications, there is a problem that dendrites are generated relatively easily. In addition, when trying to improve the SD characteristics, there is a problem that the meltdown characteristics are lowered or adjustment is difficult.
例えば特許文献２には、微多孔フィルムを製造する乾式法が開示されている。溶融押出時に高ドラフト比を採用することにより、シート化した延伸前のフィルム中のラメラ構造を制御し、これを一軸延伸することでラメラ界面での開裂を発生させ、空隙を形成する方法等が提案されている。
For example, Patent Document 2 discloses a dry method for producing a microporous film. By adopting a high draft ratio at the time of melt extrusion, the method of controlling the lamella structure in the film before stretching formed into a sheet, uniaxially stretching this to cause cleavage at the lamella interface, and forming a void, etc. Proposed.
微多孔膜の製造方法として乾式法を採用した場合、湿式法では必須となっていた溶媒の抽出工程を必要としないため、湿式法に比べて生産性に優れる。しかし、延伸速度が制限されるため、更なる生産性向上が困難であった。
When a dry method is employed as a method for producing a microporous membrane, a solvent extraction step, which has been essential in a wet method, is not required. Therefore, productivity is superior to a wet method. However, since the stretching speed is limited, it has been difficult to further improve productivity.
電池の安全性を高める為に、セパレータに耐熱性が求められている。特に、無機粒子をセパレータフィルムに塗工して、耐熱多孔質層を形成することで耐熱性が向上することが知られている（特許文献３）。しかしながら、追加の加工が必要である為、未加工品より高価である。
In order to increase battery safety, the separator is required to have heat resistance. In particular, it is known that heat resistance is improved by applying inorganic particles to a separator film to form a heat resistant porous layer (Patent Document 3). However, it is more expensive than the unprocessed product because it requires additional processing.
一方、ポリエチレンやポリプロピレン樹脂材料に融点が高い樹脂材料を混練することで、耐熱性を付与する事が知られている（特許文献４）。
On the other hand, it is known that heat resistance is imparted by kneading a resin material having a high melting point with polyethylene or polypropylene resin material (Patent Document 4).
さらには、耐熱性の高い樹脂材料を塗工により後加工する方法（特許文献５）、もしくは、ポリエチレンやポリプロピレン樹脂材料からなるフィルムに融点の高い樹脂材料からなる多孔膜を張り合わせる（特許文献６）等して、セパレータフィルムの耐熱性を向上させる取り組みも知られている。しかしながら、耐熱層として無機粒子を含む耐熱多孔質層を形成させる場合と同様に、追加の加工が必要である為、未加工品より高価である。
Furthermore, a method of post-processing a resin material having high heat resistance by coating (Patent Document 5), or a porous film made of a resin material having a high melting point is bonded to a film made of polyethylene or polypropylene resin material (Patent Document 6). Efforts to improve the heat resistance of the separator film are also known. However, as in the case of forming a heat-resistant porous layer containing inorganic particles as the heat-resistant layer, additional processing is required, which is more expensive than an unprocessed product.
しかし、電気化学的な安定性、他の物性とのバランス等の市場の要求を満たすと共に、安価で耐熱性に優れ、蓄電デバイス用セパレータフィルムとしての特性のバランスに優れた製品は存在しない。
However, there is no product that satisfies market demands such as electrochemical stability and balance with other physical properties, is inexpensive, has excellent heat resistance, and has excellent balance of properties as a separator film for power storage devices.
さらに、蓄電デバイス用セパレータフィルムには、電池に組み上げた後に実施する短絡不良実験に耐える品質も求められている。特許文献７には、耐圧不良実験として、電池を作製直後に、電池端子間に０．３ｋＶの電圧を０．５秒間印加した際に０．５ｍＡ以上の電流が流れたものを不良とする、という記載がある。特に、車載向けの電池においては、デバイスの高容量化が進み、１セルに使用するセパレータフィルムの面積が増える。この為、１セルに使用するセパレータフィルム中に１点でも上記電圧にて短絡するような欠陥が存在すると、電池の製造工程での歩留まりが落ちてしまい、不都合であった。
Furthermore, the separator film for an electricity storage device is also required to have a quality that can withstand a short-circuit failure experiment conducted after being assembled into a battery. In Patent Document 7, as a failure test for a withstand voltage, a battery having a current of 0.5 mA or more when a voltage of 0.3 kV is applied between battery terminals for 0.5 seconds immediately after the battery is manufactured is regarded as defective. There is a description. In particular, in an in-vehicle battery, the capacity of a device increases and the area of a separator film used for one cell increases. For this reason, if the separator film used in one cell has a defect that causes a short circuit even at one point, the yield in the battery manufacturing process is lowered, which is inconvenient.
近年、自動車用途向け蓄電デバイスが実用化されるようになり、デバイスの高容量化、高レート化、そして低コスト化が進んでいる。
一方、安全性に対する要求も高く、蓄電デバイス向けセパレータフィルムにも安全性の向上が要求されている。
本発明者は、上記のような問題を解決するためになされたものであり、安全性に優れたポリオレフィン微多孔膜、それを有する蓄電デバイス用セパレータフィルム、及び蓄電デバイスを提供することを目的とする。 In recent years, power storage devices for automotive applications have come into practical use, and device capacity, rate, and cost have been increasing.
On the other hand, there is a high demand for safety, and separator films for power storage devices are also required to improve safety.
The present inventor has been made to solve the above-described problems, and aims to provide a polyolefin microporous film excellent in safety, a separator film for an electricity storage device having the same, and an electricity storage device. To do.
一方、安全性に対する要求も高く、蓄電デバイス向けセパレータフィルムにも安全性の向上が要求されている。
本発明者は、上記のような問題を解決するためになされたものであり、安全性に優れたポリオレフィン微多孔膜、それを有する蓄電デバイス用セパレータフィルム、及び蓄電デバイスを提供することを目的とする。 In recent years, power storage devices for automotive applications have come into practical use, and device capacity, rate, and cost have been increasing.
On the other hand, there is a high demand for safety, and separator films for power storage devices are also required to improve safety.
The present inventor has been made to solve the above-described problems, and aims to provide a polyolefin microporous film excellent in safety, a separator film for an electricity storage device having the same, and an electricity storage device. To do.
本発明者らは、上記課題を解決するため鋭意検討したところ、課題を解決できる手段を見出し、本発明に至った。すなわち本発明は以下の特徴［１］～［１０］を有する。
［１］ ポリプロピレン系樹脂を含むポリオレフィン微多孔膜であって、
メルトダウン温度が１９５℃以上２３０℃以下であることを特徴とするポリオレフィン微多孔膜。
［２］ 前記ポリプロピレン系樹脂の重量平均分子量は、５０万以上８０万以下である［１］に記載のポリオレフィン微多孔膜；
ここで、前記重量平均分子量は、ゲル浸透クロマトグラフィー（GPC）により求めたポリスチレン換算値である。
［３］ 前記ポリプロピレン系樹脂の分子量分布が７．５以上１６以下である［２］に記載のポリオレフィン微多孔膜。 The inventors of the present invention have intensively studied to solve the above-mentioned problems. As a result, they have found means that can solve the problems and have reached the present invention. That is, the present invention has the following features [1] to [10].
[1] A polyolefin microporous membrane containing a polypropylene resin,
A polyolefin microporous membrane having a meltdown temperature of 195 ° C or higher and 230 ° C or lower.
[2] The polyolefin microporous membrane according to [1], wherein the polypropylene resin has a weight average molecular weight of 500,000 to 800,000;
Here, the said weight average molecular weight is the polystyrene conversion value calculated | required by the gel permeation chromatography (GPC).
[3] The polyolefin microporous membrane according to [2], wherein the polypropylene resin has a molecular weight distribution of 7.5 or more and 16 or less.
［１］ ポリプロピレン系樹脂を含むポリオレフィン微多孔膜であって、
メルトダウン温度が１９５℃以上２３０℃以下であることを特徴とするポリオレフィン微多孔膜。
［２］ 前記ポリプロピレン系樹脂の重量平均分子量は、５０万以上８０万以下である［１］に記載のポリオレフィン微多孔膜；
ここで、前記重量平均分子量は、ゲル浸透クロマトグラフィー（GPC）により求めたポリスチレン換算値である。
［３］ 前記ポリプロピレン系樹脂の分子量分布が７．５以上１６以下である［２］に記載のポリオレフィン微多孔膜。 The inventors of the present invention have intensively studied to solve the above-mentioned problems. As a result, they have found means that can solve the problems and have reached the present invention. That is, the present invention has the following features [1] to [10].
[1] A polyolefin microporous membrane containing a polypropylene resin,
A polyolefin microporous membrane having a meltdown temperature of 195 ° C or higher and 230 ° C or lower.
[2] The polyolefin microporous membrane according to [1], wherein the polypropylene resin has a weight average molecular weight of 500,000 to 800,000;
Here, the said weight average molecular weight is the polystyrene conversion value calculated | required by the gel permeation chromatography (GPC).
[3] The polyolefin microporous membrane according to [2], wherein the polypropylene resin has a molecular weight distribution of 7.5 or more and 16 or less.
［４］ 前記ポリプロピレン系樹脂の２００℃条件によるゼロ剪断粘度が、１３０００～２００００Ｐａ・ｓである［１］～［３］のいずれかに記載のポリオレフィン微多孔膜。
［５］ 更にポリエチレン系樹脂を含む［１］～［４］のいずれかに記載のポリオレフィン微多孔膜。
［６］ 前記ポリエチレン系樹脂を中間層とし、前記ポリプロピレン系樹脂を表層とする積層構造である［５］に記載のポリオレフィン微多孔膜。
［７］ 単位面積耐電圧が３ｋＶ／ｍ２以上である［１］～［６］のいずれかに記載のポリオレフィン微多孔膜；
ここで、前記単位面積耐電圧は、１０ｃｍ×１００ｃｍサイズの試験片に対して電圧をかけた短絡試験において、導通しない電圧を測定することによって得られた値である。 [4] The polyolefin microporous membrane according to any one of [1] to [3], wherein the polypropylene-based resin has a zero shear viscosity of 13000 to 20000 Pa · s under a 200 ° C. condition.
[5] The polyolefin microporous membrane according to any one of [1] to [4], further comprising a polyethylene resin.
[6] The polyolefin microporous membrane according to [5], which has a laminated structure in which the polyethylene resin is an intermediate layer and the polypropylene resin is a surface layer.
[7] The polyolefin microporous membrane according to any one of [1] to [6], wherein the unit area withstand voltage is 3 kV / m 2 or more;
Here, the unit area withstand voltage is a value obtained by measuring a non-conducting voltage in a short-circuit test in which a voltage is applied to a 10 cm × 100 cm size test piece.
［５］ 更にポリエチレン系樹脂を含む［１］～［４］のいずれかに記載のポリオレフィン微多孔膜。
［６］ 前記ポリエチレン系樹脂を中間層とし、前記ポリプロピレン系樹脂を表層とする積層構造である［５］に記載のポリオレフィン微多孔膜。
［７］ 単位面積耐電圧が３ｋＶ／ｍ２以上である［１］～［６］のいずれかに記載のポリオレフィン微多孔膜；
ここで、前記単位面積耐電圧は、１０ｃｍ×１００ｃｍサイズの試験片に対して電圧をかけた短絡試験において、導通しない電圧を測定することによって得られた値である。 [4] The polyolefin microporous membrane according to any one of [1] to [3], wherein the polypropylene-based resin has a zero shear viscosity of 13000 to 20000 Pa · s under a 200 ° C. condition.
[5] The polyolefin microporous membrane according to any one of [1] to [4], further comprising a polyethylene resin.
[6] The polyolefin microporous membrane according to [5], which has a laminated structure in which the polyethylene resin is an intermediate layer and the polypropylene resin is a surface layer.
[7] The polyolefin microporous membrane according to any one of [1] to [6], wherein the unit area withstand voltage is 3 kV / m 2 or more;
Here, the unit area withstand voltage is a value obtained by measuring a non-conducting voltage in a short-circuit test in which a voltage is applied to a 10 cm × 100 cm size test piece.
［８］ ［１］～［７］のいずれかに記載のポリオレフィン微多孔膜を有する蓄電デバイス用セパレータフィルム。
［９］ 前記ポリオレフィン微多孔膜の片面または両面に耐熱多孔質層が積層され、
前記耐熱多孔質層が、耐熱性微粒子と有機バインダとを含み、
前記耐熱性微粒子の含有量が、前記耐熱多孔質層に対して８０重量％以上９９重量％以下であり、
前記耐熱多孔質層の厚さが２μｍ～１０μｍである［８］に記載の蓄電デバイス用セパレータフィルム。
［１０］ ［８］または［９］に記載の蓄電デバイス用セパレータフィルムと、正極と、負極とを備える蓄電デバイス。 [8] A separator film for an electricity storage device having the polyolefin microporous film according to any one of [1] to [7].
[9] A heat-resistant porous layer is laminated on one side or both sides of the polyolefin microporous membrane,
The heat-resistant porous layer contains heat-resistant fine particles and an organic binder,
The content of the heat-resistant fine particles is 80 wt% or more and 99 wt% or less with respect to the heat-resistant porous layer,
The separator film for an electricity storage device according to [8], wherein the heat-resistant porous layer has a thickness of 2 μm to 10 μm.
[10] An electricity storage device comprising the separator film for an electricity storage device according to [8] or [9], a positive electrode, and a negative electrode.
［９］ 前記ポリオレフィン微多孔膜の片面または両面に耐熱多孔質層が積層され、
前記耐熱多孔質層が、耐熱性微粒子と有機バインダとを含み、
前記耐熱性微粒子の含有量が、前記耐熱多孔質層に対して８０重量％以上９９重量％以下であり、
前記耐熱多孔質層の厚さが２μｍ～１０μｍである［８］に記載の蓄電デバイス用セパレータフィルム。
［１０］ ［８］または［９］に記載の蓄電デバイス用セパレータフィルムと、正極と、負極とを備える蓄電デバイス。 [8] A separator film for an electricity storage device having the polyolefin microporous film according to any one of [1] to [7].
[9] A heat-resistant porous layer is laminated on one side or both sides of the polyolefin microporous membrane,
The heat-resistant porous layer contains heat-resistant fine particles and an organic binder,
The content of the heat-resistant fine particles is 80 wt% or more and 99 wt% or less with respect to the heat-resistant porous layer,
The separator film for an electricity storage device according to [8], wherein the heat-resistant porous layer has a thickness of 2 μm to 10 μm.
[10] An electricity storage device comprising the separator film for an electricity storage device according to [8] or [9], a positive electrode, and a negative electrode.
本発明のポリオレフィン微多孔膜は、耐熱性に優れる。本発明のポリオレフィン微多孔膜を有する蓄電デバイス用セパレータフィルムを用いることにより、蓄電デバイスの安全性向上に寄与することが出来る。
The polyolefin microporous membrane of the present invention is excellent in heat resistance. By using the separator film for an electricity storage device having the polyolefin microporous membrane of the present invention, it is possible to contribute to improving the safety of the electricity storage device.
以下、本発明の実施形態について説明するが、本発明はこれに限定されず、本発明の効果を奏する範囲で適宜変更可能である。
本発明者は、重量平均分子量と分子量分布が適切な範囲のポリプロピレン樹脂を用い、かつ、乾式法による一軸延伸プロセスとを組み合わせる事により、優れた生産性（コスト）と耐熱性、そしてセパレータフィルムとしての特性のバランスに優れた微多孔膜が得られることを見出した。これにより蓄電デバイスのコスト、安全性を両立する事が期待できる。
また、本発明のポリオレフィン微多孔膜によれば、従来と同程度の空孔率でありながら従来よりも表面開口率を下げることができ、例えば蓄電デバイスの短絡を抑えることができる。 Hereinafter, although embodiment of this invention is described, this invention is not limited to this, It can change suitably in the range with the effect of this invention.
The present inventor uses a polypropylene resin having an appropriate range of weight average molecular weight and molecular weight distribution, and is combined with a uniaxial stretching process by a dry method to provide excellent productivity (cost), heat resistance, and a separator film. It was found that a microporous membrane having an excellent balance of properties can be obtained. Thereby, it can be expected that both the cost and the safety of the electricity storage device are compatible.
Moreover, according to the polyolefin microporous film of the present invention, the surface aperture ratio can be lowered as compared with the conventional case while the porosity is about the same as the conventional case, and for example, a short circuit of the electricity storage device can be suppressed.
本発明者は、重量平均分子量と分子量分布が適切な範囲のポリプロピレン樹脂を用い、かつ、乾式法による一軸延伸プロセスとを組み合わせる事により、優れた生産性（コスト）と耐熱性、そしてセパレータフィルムとしての特性のバランスに優れた微多孔膜が得られることを見出した。これにより蓄電デバイスのコスト、安全性を両立する事が期待できる。
また、本発明のポリオレフィン微多孔膜によれば、従来と同程度の空孔率でありながら従来よりも表面開口率を下げることができ、例えば蓄電デバイスの短絡を抑えることができる。 Hereinafter, although embodiment of this invention is described, this invention is not limited to this, It can change suitably in the range with the effect of this invention.
The present inventor uses a polypropylene resin having an appropriate range of weight average molecular weight and molecular weight distribution, and is combined with a uniaxial stretching process by a dry method to provide excellent productivity (cost), heat resistance, and a separator film. It was found that a microporous membrane having an excellent balance of properties can be obtained. Thereby, it can be expected that both the cost and the safety of the electricity storage device are compatible.
Moreover, according to the polyolefin microporous film of the present invention, the surface aperture ratio can be lowered as compared with the conventional case while the porosity is about the same as the conventional case, and for example, a short circuit of the electricity storage device can be suppressed.
（ポリオレフィン微多孔膜）
本発明のポリオレフィン微多孔膜は、ポリプロピレン（以降、ＰＰという場合がある。）系樹脂を含む。ポリプロピレン系樹脂の重量平均分子量は、５０万以上であることが好ましく、５４万以上であることがより好ましく、最も好ましくは５５万以上である。また、その上限は８０万以下であることが好ましく、より好ましくは７５万以下、最も好ましくは７０万以下である。
ＧＰＣによるポリスチレン換算重量平均分子量が５０万未満であると、力学特性やメルトダウン温度が低下するために好ましくない。また、重量平均分子量が８０万を超えると、フィルムの加工性が低下し、セパレータフィルムのコストが増す為に好ましくない。 (Polyolefin microporous membrane)
The polyolefin microporous membrane of the present invention contains a polypropylene (hereinafter sometimes referred to as PP) resin. The weight average molecular weight of the polypropylene resin is preferably 500,000 or more, more preferably 540,000 or more, and most preferably 550,000 or more. Further, the upper limit is preferably 800,000 or less, more preferably 750,000 or less, and most preferably 700,000 or less.
If the weight average molecular weight in terms of polystyrene by GPC is less than 500,000, the mechanical properties and the meltdown temperature are lowered, which is not preferable. Moreover, when the weight average molecular weight exceeds 800,000, the processability of the film is lowered and the cost of the separator film is increased, which is not preferable.
本発明のポリオレフィン微多孔膜は、ポリプロピレン（以降、ＰＰという場合がある。）系樹脂を含む。ポリプロピレン系樹脂の重量平均分子量は、５０万以上であることが好ましく、５４万以上であることがより好ましく、最も好ましくは５５万以上である。また、その上限は８０万以下であることが好ましく、より好ましくは７５万以下、最も好ましくは７０万以下である。
ＧＰＣによるポリスチレン換算重量平均分子量が５０万未満であると、力学特性やメルトダウン温度が低下するために好ましくない。また、重量平均分子量が８０万を超えると、フィルムの加工性が低下し、セパレータフィルムのコストが増す為に好ましくない。 (Polyolefin microporous membrane)
The polyolefin microporous membrane of the present invention contains a polypropylene (hereinafter sometimes referred to as PP) resin. The weight average molecular weight of the polypropylene resin is preferably 500,000 or more, more preferably 540,000 or more, and most preferably 550,000 or more. Further, the upper limit is preferably 800,000 or less, more preferably 750,000 or less, and most preferably 700,000 or less.
If the weight average molecular weight in terms of polystyrene by GPC is less than 500,000, the mechanical properties and the meltdown temperature are lowered, which is not preferable. Moreover, when the weight average molecular weight exceeds 800,000, the processability of the film is lowered and the cost of the separator film is increased, which is not preferable.
さらに、分子量分布は７．５以上であることが好ましく、８．０以上であることがより好ましく、さらに８．５以上であることが好ましく、最も好ましくは９．０以上である。その上限は１６以下であることが好ましく、１５以下であることがより好ましく、さらに１４以下であることが好ましく、最も好ましくは、１３以下である。
分子量分布が小さいと、粘度特性が低下し、メルトダウン温度が低下する為に好ましくない。分子量分布が大きすぎると加工性が低下し、コストが増す為に好ましくない。
重量平均分子量は、ゲル浸透クロマトグラフィー（GPC）により求めたポリスチレン換算値である。また、分子量分布は、この方法により求めた重量平均分子量を用いて算出した値である。 Furthermore, the molecular weight distribution is preferably 7.5 or more, more preferably 8.0 or more, further preferably 8.5 or more, and most preferably 9.0 or more. The upper limit is preferably 16 or less, more preferably 15 or less, further preferably 14 or less, and most preferably 13 or less.
If the molecular weight distribution is small, the viscosity characteristics are lowered and the meltdown temperature is lowered, which is not preferable. If the molecular weight distribution is too large, the processability decreases and the cost increases, which is not preferable.
The weight average molecular weight is a polystyrene conversion value determined by gel permeation chromatography (GPC). The molecular weight distribution is a value calculated using the weight average molecular weight determined by this method.
分子量分布が小さいと、粘度特性が低下し、メルトダウン温度が低下する為に好ましくない。分子量分布が大きすぎると加工性が低下し、コストが増す為に好ましくない。
重量平均分子量は、ゲル浸透クロマトグラフィー（GPC）により求めたポリスチレン換算値である。また、分子量分布は、この方法により求めた重量平均分子量を用いて算出した値である。 Furthermore, the molecular weight distribution is preferably 7.5 or more, more preferably 8.0 or more, further preferably 8.5 or more, and most preferably 9.0 or more. The upper limit is preferably 16 or less, more preferably 15 or less, further preferably 14 or less, and most preferably 13 or less.
If the molecular weight distribution is small, the viscosity characteristics are lowered and the meltdown temperature is lowered, which is not preferable. If the molecular weight distribution is too large, the processability decreases and the cost increases, which is not preferable.
The weight average molecular weight is a polystyrene conversion value determined by gel permeation chromatography (GPC). The molecular weight distribution is a value calculated using the weight average molecular weight determined by this method.
さらに、ＰＰ系樹脂の示差走査熱量計（ＤＳＣ）にて測定した結晶融解ピーク温度（融点）は、１５５℃以上であることが好ましく、１５７℃以上がより好ましく、１５９℃以上がさらに好ましく、最も好ましくは１６０℃以上である。上限は１７５℃以下であることが好ましく、１７３℃以下がより好ましく、１７０℃以下がさらに好ましく、最も好ましくは１６９℃以下である。ＰＰ系樹脂の結晶融解ピーク温度が低すぎると、微多孔膜の加工特性が低下するために好ましくない。
Furthermore, the crystal melting peak temperature (melting point) measured with a differential scanning calorimeter (DSC) of the PP resin is preferably 155 ° C. or higher, more preferably 157 ° C. or higher, and further preferably 159 ° C. or higher. Preferably it is 160 degreeC or more. The upper limit is preferably 175 ° C. or lower, more preferably 173 ° C. or lower, further preferably 170 ° C. or lower, and most preferably 169 ° C. or lower. When the crystal melting peak temperature of the PP resin is too low, the processing characteristics of the microporous film are deteriorated, which is not preferable.
ＰＰ系樹脂の２００℃条件によるゼロ剪断粘度は、１３０００～２００００Ｐａ・ｓの範囲内であることが好ましい。１３０００Ｐａ・ｓ以上のゼロ剪断粘度とすることでポリオレフィン微多孔膜のメルトダウン温度を少なくとも２００℃超にすることが可能となる。２００００Ｐａ・ｓ以下のゼロ剪断粘度とすることで、形状の保持特性を従来よりも十分に向上させることができ、２００℃超の環境下においてもセパレータの形状を確実に安定して維持できる。ＰＰ系樹脂のゼロ剪断粘度は１４０００～１９０００Ｐａ・ｓがより好ましく、１５０００～１８０００Ｐａ・ｓが更に好ましい。
The zero shear viscosity of the PP resin under the 200 ° C. condition is preferably in the range of 13000 to 20000 Pa · s. By setting the zero shear viscosity to 13000 Pa · s or more, the meltdown temperature of the polyolefin microporous membrane can be at least 200 ° C. or higher. By setting the zero shear viscosity to 20000 Pa · s or less, the shape retention property can be sufficiently improved as compared with the conventional case, and the shape of the separator can be reliably and stably maintained even in an environment of more than 200 ° C. The zero shear viscosity of the PP resin is more preferably 14000 to 19000 Pa · s, and further preferably 15000 to 18000 Pa · s.
ＰＰ系樹脂とは、プロピレンをモノマーの主成分として８０％以上含む重合物であり、このような重合物を単独で使用してもよいし、複数種混合してもよい。また、ＰＰ系樹脂には、一般的に界面活性剤、老化防止剤、可塑剤、難燃剤、着色剤等の添加剤が、合目的的に含まれており、本発明のＰＰ系樹脂においても、これらの添加剤が含まれていても良い。
The PP resin is a polymer containing 80% or more of propylene as a main component of the monomer, and such a polymer may be used alone or a plurality of types may be mixed. In addition, additives such as surfactants, anti-aging agents, plasticizers, flame retardants, and colorants are generally included in PP resins for the purpose, and the PP resins of the present invention are also included. These additives may be contained.
ＰＰ系樹脂は立体規則性の高いものが好ましい。ＰＰ系樹脂のペンタッド分率が８０％以上であることが好ましく、９０％以上であることがより好ましい。
PP resin is preferably highly stereoregular. The pentad fraction of the PP resin is preferably 80% or more, and more preferably 90% or more.
本発明のポリオレフィン微多孔膜は、メルトダウン（ＭＤ）温度が１９５℃以上であり、好ましくは２００℃以上、より好ましくは２００．１℃以上、最も好ましくは２０１．０℃以上である。上限については、高温であればあるほど好ましいが、通常は、２３０℃以下であり、２２５℃以下である場合や、２２０℃以下である場合も好ましい。
The polyolefin microporous membrane of the present invention has a meltdown (MD) temperature of 195 ° C. or higher, preferably 200 ° C. or higher, more preferably 200.1 ° C. or higher, and most preferably 201.0 ° C. or higher. About an upper limit, although it is so preferable that it is high temperature, Usually, it is 230 degrees C or less, the case where it is 225 degrees C or less, and the case where it is 220 degrees C or less are also preferable.
本発明の一実施形態のポリオレフィン微多孔膜におけるポリプロピレン系樹脂の含有量は、ポリオレフィン微多孔膜の総重量に対して、９０重量％以上であってもよい。９５重量％以上であっても、または９９重量％以上であってもよい。ポリオレフィン微多孔膜の材料がポリプロピレン系樹脂であることがもっとも好ましい。
The content of the polypropylene resin in the polyolefin microporous membrane of one embodiment of the present invention may be 90% by weight or more based on the total weight of the polyolefin microporous membrane. It may be 95% by weight or more, or 99% by weight or more. Most preferably, the material of the polyolefin microporous membrane is a polypropylene resin.
本発明のその他の実施形態のポリオレフィン微多孔膜は、更にポリエチレン系樹脂を含んでも良い。
The polyolefin microporous membrane according to another embodiment of the present invention may further contain a polyethylene resin.
その場合、ポリオレフィン微多孔膜における、ポリプロピレン系樹脂とポリエチレン（以降、ＰＥという場合がある。）系樹脂との合計含有量は、ポリオレフィン微多孔膜の総重量に対して、９０重量％以上であってもよい。９５重量％であっても、または９９重量％以上であってもよい。ポリオレフィン微多孔膜の材料がポリプロピレン系樹脂とポリエチレン系樹脂であることがもっとも好ましい。
In that case, the total content of the polypropylene resin and the polyethylene (hereinafter sometimes referred to as PE) resin in the polyolefin microporous membrane was 90% by weight or more based on the total weight of the polyolefin microporous membrane. May be. It may be 95% by weight or 99% by weight or more. The material of the polyolefin microporous membrane is most preferably a polypropylene resin and a polyethylene resin.
ＰＥ系樹脂とは、エチレンをモノマーの主成分として８０％以上含む重合物であり、このような重合物を単独で使用してもよいし、複数種混合してもよい。また、ＰＥ系樹脂には、一般的に界面活性剤、老化防止剤、可塑剤、難燃剤、着色剤等の添加剤が、合目的的に含まれており、本発明のＰＰ系樹脂においても、これらの添加剤が含まれていても良い。
ＰＥ系樹脂の重量平均分子量は、２２０，０００以上４００，０００以下であることが好ましく、３００，０００以上４００，０００以下であることがより好ましい。
ＰＥ系樹脂の分子量分布は、６．０以上１５．０以下であることが好ましく、７．５以上１０．０以下であることがより好ましい。 The PE resin is a polymer containing 80% or more of ethylene as a main component of the monomer, and such a polymer may be used alone or a plurality of types may be mixed. The PE resin generally contains additives such as surfactants, anti-aging agents, plasticizers, flame retardants, and colorants for the purpose. These additives may be contained.
The weight average molecular weight of the PE resin is preferably 220,000 or more and 400,000 or less, and more preferably 300,000 or more and 400,000 or less.
The molecular weight distribution of the PE-based resin is preferably 6.0 or more and 15.0 or less, and more preferably 7.5 or more and 10.0 or less.
ＰＥ系樹脂の重量平均分子量は、２２０，０００以上４００，０００以下であることが好ましく、３００，０００以上４００，０００以下であることがより好ましい。
ＰＥ系樹脂の分子量分布は、６．０以上１５．０以下であることが好ましく、７．５以上１０．０以下であることがより好ましい。 The PE resin is a polymer containing 80% or more of ethylene as a main component of the monomer, and such a polymer may be used alone or a plurality of types may be mixed. The PE resin generally contains additives such as surfactants, anti-aging agents, plasticizers, flame retardants, and colorants for the purpose. These additives may be contained.
The weight average molecular weight of the PE resin is preferably 220,000 or more and 400,000 or less, and more preferably 300,000 or more and 400,000 or less.
The molecular weight distribution of the PE-based resin is preferably 6.0 or more and 15.0 or less, and more preferably 7.5 or more and 10.0 or less.
ＰＥ系樹脂の密度は、０．９５０ｇ／ｃｍ３以上０．９７０ｇ／ｃｍ３以下であることが好ましい。ＰＥ系樹脂は、密度が０．９６０ｇ／ｃｍ３以上の高密度ポリエチレンがより好ましいが、中密度ポリエチレンでもよい。
ＰＥ系樹脂の融点は、１２５℃以上１４０℃以下であることが好ましく、１３０℃以上１３６℃以下であることがより好ましい。
ＰＥ系樹脂のメルトインデックスは、０．２０以上０．４０以下であることが好ましく、０．３０以上０．４０以下であることがより好ましい。 The density of PE-based resin is preferably not more than 0.950 g / cm 3 or more 0.970 g / cm 3. The PE resin is more preferably high density polyethylene having a density of 0.960 g / cm 3 or more, but may be medium density polyethylene.
The melting point of the PE-based resin is preferably 125 ° C. or higher and 140 ° C. or lower, and more preferably 130 ° C. or higher and 136 ° C. or lower.
The melt index of the PE resin is preferably 0.20 or more and 0.40 or less, and more preferably 0.30 or more and 0.40 or less.
ＰＥ系樹脂の融点は、１２５℃以上１４０℃以下であることが好ましく、１３０℃以上１３６℃以下であることがより好ましい。
ＰＥ系樹脂のメルトインデックスは、０．２０以上０．４０以下であることが好ましく、０．３０以上０．４０以下であることがより好ましい。 The density of PE-based resin is preferably not more than 0.950 g / cm 3 or more 0.970 g / cm 3. The PE resin is more preferably high density polyethylene having a density of 0.960 g / cm 3 or more, but may be medium density polyethylene.
The melting point of the PE-based resin is preferably 125 ° C. or higher and 140 ° C. or lower, and more preferably 130 ° C. or higher and 136 ° C. or lower.
The melt index of the PE resin is preferably 0.20 or more and 0.40 or less, and more preferably 0.30 or more and 0.40 or less.
本発明のポリオレフィン微多孔膜は、ＰＰ系樹脂とＰＥ系樹脂とから構成されていてもよいし、ＰＰ系樹脂のみから構成されていてもよい。ＰＰ系樹脂のみから構成するとは、ＰＰ系樹脂を単層のフィルムとして構成させる事を示す。
The polyolefin microporous membrane of the present invention may be composed of a PP resin and a PE resin, or may be composed only of a PP resin. Constructing only from a PP resin indicates that the PP resin is configured as a single layer film.
また、ＰＰ系樹脂とＰＥ系樹脂から構成する、とは、ポリオレフィン微多孔膜であって、ＰＰ系樹脂とＰＥ系樹脂を混練等によりブレンドし、単層のフィルムとして構成させる場合や、ＰＰ系樹脂とＰＥ系樹脂とを積層させた構成を示す。積層させた場合は、ＰＰ/ＰＥの２層構造や、３層構造、さらに４層以上の積層構造であっても良い。
好ましい形態は、ＰＰ系樹脂の単層のフィルム、および３層構造のフィルムである。３層の積層構造は、ポリエチレンを中間層とし、ポリプロピレンを表層とする、即ち外層がポリプロピレンで内層がポリエチレンになるように積層する場合（ＰＰ／ＰＥ／ＰＰ）や、外層がポリエチレンで内層がポリプロピレンになるように積層する場合（ＰＥ／ＰＰ／ＰＥ）がある。積層構造は、上記のいずれかに特定されるものではないが、カールがなく、外傷を受け難くポリオレフィン微多孔膜の耐熱性、機械的強度等がよく、また蓄電デバイス用セパレータとしての安全性、信頼性等々の特性を満たす上から、外層がポリプロピレンで内層がポリエチレンになるように３層積層する場合（ＰＰ／ＰＥ／ＰＰ）が最も好適である。 Further, it is composed of a PP-based resin and a PE-based resin, which is a polyolefin microporous film. When a PP-based resin and a PE-based resin are blended by kneading or the like to form a single layer film, The structure which laminated | stacked resin and PE resin is shown. When laminated, it may have a two-layer structure of PP / PE, a three-layer structure, or a laminated structure of four or more layers.
Preferable forms are a single layer film of PP resin and a film having a three-layer structure. The three-layer structure has polyethylene as the intermediate layer and polypropylene as the surface layer, that is, when the outer layer is polypropylene and the inner layer is polyethylene (PP / PE / PP), or the outer layer is polyethylene and the inner layer is polypropylene. (PE / PP / PE). Although the laminated structure is not specified as any of the above, it has no curling, is not easily damaged, has good heat resistance, mechanical strength, etc. of the polyolefin microporous membrane, and also has safety as a separator for an electricity storage device, From the viewpoint of satisfying characteristics such as reliability, the case where three layers are laminated so that the outer layer is polypropylene and the inner layer is polyethylene (PP / PE / PP) is most preferable.
好ましい形態は、ＰＰ系樹脂の単層のフィルム、および３層構造のフィルムである。３層の積層構造は、ポリエチレンを中間層とし、ポリプロピレンを表層とする、即ち外層がポリプロピレンで内層がポリエチレンになるように積層する場合（ＰＰ／ＰＥ／ＰＰ）や、外層がポリエチレンで内層がポリプロピレンになるように積層する場合（ＰＥ／ＰＰ／ＰＥ）がある。積層構造は、上記のいずれかに特定されるものではないが、カールがなく、外傷を受け難くポリオレフィン微多孔膜の耐熱性、機械的強度等がよく、また蓄電デバイス用セパレータとしての安全性、信頼性等々の特性を満たす上から、外層がポリプロピレンで内層がポリエチレンになるように３層積層する場合（ＰＰ／ＰＥ／ＰＰ）が最も好適である。 Further, it is composed of a PP-based resin and a PE-based resin, which is a polyolefin microporous film. When a PP-based resin and a PE-based resin are blended by kneading or the like to form a single layer film, The structure which laminated | stacked resin and PE resin is shown. When laminated, it may have a two-layer structure of PP / PE, a three-layer structure, or a laminated structure of four or more layers.
Preferable forms are a single layer film of PP resin and a film having a three-layer structure. The three-layer structure has polyethylene as the intermediate layer and polypropylene as the surface layer, that is, when the outer layer is polypropylene and the inner layer is polyethylene (PP / PE / PP), or the outer layer is polyethylene and the inner layer is polypropylene. (PE / PP / PE). Although the laminated structure is not specified as any of the above, it has no curling, is not easily damaged, has good heat resistance, mechanical strength, etc. of the polyolefin microporous membrane, and also has safety as a separator for an electricity storage device, From the viewpoint of satisfying characteristics such as reliability, the case where three layers are laminated so that the outer layer is polypropylene and the inner layer is polyethylene (PP / PE / PP) is most preferable.
ポリオレフィン微多孔膜が複数枚のポリプロピレンフィルムまたはポリエチレンフィルムが積層されたものである場合、各層を構成するＰＰ系樹脂またはＰＥ系樹脂は、分子量が等しくてもよいし、それぞれ異なっていてもよい。
When the polyolefin microporous film is a laminate of a plurality of polypropylene films or polyethylene films, the PP resin or PE resin constituting each layer may have the same or different molecular weight.
ポリオレフィン微多孔膜の全体の厚みは、蓄電デバイス用セパレータとしての機械的強度、性能、小型化等の面から７．０μｍ以上であることが好ましく、７．５μｍ以上であることがより好ましく、さらに８．０μｍ以上であることが好ましく、最も好ましくは８．５μｍ以上である。上限は５０μｍ以下であることが好ましく、４５μｍ以下であることがより好ましく、さらに好ましくは４２μｍ以下である。
膜厚が薄すぎると、破膜が生じやすくなり、デバイスの短絡率が向上し、安全性が低下する恐れが有る為、好ましくない。また、膜厚が厚すぎると、蓄電デバイス用セパレータとして用いた場合の安全性は向上するが、イオン伝導性が低下し、デバイスのレート特性が低下する為、好ましくない。 The total thickness of the polyolefin microporous membrane is preferably 7.0 μm or more, more preferably 7.5 μm or more, from the viewpoint of mechanical strength, performance, miniaturization, etc., as a power storage device separator. It is preferably 8.0 μm or more, and most preferably 8.5 μm or more. The upper limit is preferably 50 μm or less, more preferably 45 μm or less, and still more preferably 42 μm or less.
If the film thickness is too thin, film breakage is likely to occur, the short circuit rate of the device is improved, and the safety may be lowered. On the other hand, if the film thickness is too thick, the safety when used as a separator for an electricity storage device is improved, but the ion conductivity is lowered and the rate characteristics of the device are lowered.
膜厚が薄すぎると、破膜が生じやすくなり、デバイスの短絡率が向上し、安全性が低下する恐れが有る為、好ましくない。また、膜厚が厚すぎると、蓄電デバイス用セパレータとして用いた場合の安全性は向上するが、イオン伝導性が低下し、デバイスのレート特性が低下する為、好ましくない。 The total thickness of the polyolefin microporous membrane is preferably 7.0 μm or more, more preferably 7.5 μm or more, from the viewpoint of mechanical strength, performance, miniaturization, etc., as a power storage device separator. It is preferably 8.0 μm or more, and most preferably 8.5 μm or more. The upper limit is preferably 50 μm or less, more preferably 45 μm or less, and still more preferably 42 μm or less.
If the film thickness is too thin, film breakage is likely to occur, the short circuit rate of the device is improved, and the safety may be lowered. On the other hand, if the film thickness is too thick, the safety when used as a separator for an electricity storage device is improved, but the ion conductivity is lowered and the rate characteristics of the device are lowered.
ポリオレフィン微多孔膜の厚みは、走査型電子顕微鏡（ＳＥＭ）により、微多孔膜の断面を撮影した画像を画像解析すること、もしくは、打点式の厚み測定装置等により求めることができる。
The thickness of the polyolefin microporous film can be determined by image analysis of an image obtained by photographing a cross section of the microporous film with a scanning electron microscope (SEM), or by a dot-type thickness measuring device.
本発明の各実施例形態のポリオレフィン微多孔膜の透気度は８０ｓ／１００ｃｃ以上であることが好ましく、９０ｓ／１００ｃｃ以上であることがより好ましく、さらに１００ｓ／１００ｃｃ以上であることが好ましく、最も好ましくは１０５ｓ／１００ｃｃ以上である。上限は７００ｓ／１００ｃｃ以下であることが好ましく、６５０ｓ／１００ｃｃ以下であることがより好ましく、さらに好ましくは６００ｓ／１００ｃｃ以下であり、２００ｓ／１００ｃｃ以下であることが最も好ましい。
透気度が低すぎると、電池を作動させた際に短絡しやすくなる恐れがある為、好ましくない。また、透気度が高すぎると、イオンの移動度が低くなり電池として作動しなくなる恐れがある為、好ましくない。 The air permeability of the polyolefin microporous membrane of each embodiment of the present invention is preferably 80 s / 100 cc or more, more preferably 90 s / 100 cc or more, and further preferably 100 s / 100 cc or more. Preferably it is 105 s / 100cc or more. The upper limit is preferably 700 s / 100 cc or less, more preferably 650 s / 100 cc or less, still more preferably 600 s / 100 cc or less, and most preferably 200 s / 100 cc or less.
If the air permeability is too low, there is a risk of short circuit when the battery is operated, which is not preferable. Further, if the air permeability is too high, the mobility of ions is lowered, and the battery may not be operated, which is not preferable.
透気度が低すぎると、電池を作動させた際に短絡しやすくなる恐れがある為、好ましくない。また、透気度が高すぎると、イオンの移動度が低くなり電池として作動しなくなる恐れがある為、好ましくない。 The air permeability of the polyolefin microporous membrane of each embodiment of the present invention is preferably 80 s / 100 cc or more, more preferably 90 s / 100 cc or more, and further preferably 100 s / 100 cc or more. Preferably it is 105 s / 100cc or more. The upper limit is preferably 700 s / 100 cc or less, more preferably 650 s / 100 cc or less, still more preferably 600 s / 100 cc or less, and most preferably 200 s / 100 cc or less.
If the air permeability is too low, there is a risk of short circuit when the battery is operated, which is not preferable. Further, if the air permeability is too high, the mobility of ions is lowered, and the battery may not be operated, which is not preferable.
本発明の各実施例形態のポリオレフィン微多孔膜の空孔率は３０％以上であることが好ましく、より好ましくは４０％以上、さらに好ましくは５０％以上である。上限は７０％以下であることが好ましく、より好ましくは６０％以下であり、さらに好ましくは５８％以下である。
空孔率が高すぎると、機械的強度が悪くなるし、電池を作動させた際に短絡しやすくなる恐れがある為、好ましくない。また、空孔率が低すぎると、イオンの移動度が低くなり電池として作動しなくなる恐れがある為、好ましくない。 The porosity of the polyolefin microporous membrane of each embodiment of the present invention is preferably 30% or more, more preferably 40% or more, and further preferably 50% or more. The upper limit is preferably 70% or less, more preferably 60% or less, and still more preferably 58% or less.
If the porosity is too high, the mechanical strength is deteriorated and there is a risk of short circuiting when the battery is operated. On the other hand, if the porosity is too low, the mobility of ions becomes low and the battery may not be operated.
空孔率が高すぎると、機械的強度が悪くなるし、電池を作動させた際に短絡しやすくなる恐れがある為、好ましくない。また、空孔率が低すぎると、イオンの移動度が低くなり電池として作動しなくなる恐れがある為、好ましくない。 The porosity of the polyolefin microporous membrane of each embodiment of the present invention is preferably 30% or more, more preferably 40% or more, and further preferably 50% or more. The upper limit is preferably 70% or less, more preferably 60% or less, and still more preferably 58% or less.
If the porosity is too high, the mechanical strength is deteriorated and there is a risk of short circuiting when the battery is operated. On the other hand, if the porosity is too low, the mobility of ions becomes low and the battery may not be operated.
本発明の各実施例形態のポリオレフィン微多孔膜の単位面積耐電圧は、３ｋＶ／ｍ２以上であることが好ましく、４ｋＶ／ｍ２以上であることがより好ましく、５ｋＶ／ｍ２以上であることがさらに好ましい。６ｋＶ／ｍ２以上であることがもっとも好ましい。
なお、単位面積耐電圧は、１０ｃｍ×１００ｃｍサイズの試験片に対して電圧をかけた短絡試験において、導通しない電圧を測定することによって得られた値である。
すなわち、本発明のポリオレフィン微多孔膜は、１０ｃｍ×１００ｃｍの試験片について、０．３ｋＶの電圧をかけた際の短絡試験において導通しないポリオレフィン微多孔膜であることが好ましい。 The unit area withstand voltage of the polyolefin microporous membrane of each embodiment of the present invention is preferably 3 kV / m 2 or more, more preferably 4 kV / m 2 or more, and 5 kV / m 2 or more. Is more preferable. Most preferably, it is 6 kV / m 2 or more.
The unit area withstand voltage is a value obtained by measuring a voltage that does not conduct in a short-circuit test in which a voltage is applied to a 10 cm × 100 cm size test piece.
That is, the polyolefin microporous membrane of the present invention is preferably a polyolefin microporous membrane that does not conduct in a short-circuit test when a voltage of 0.3 kV is applied to a 10 cm × 100 cm test piece.
なお、単位面積耐電圧は、１０ｃｍ×１００ｃｍサイズの試験片に対して電圧をかけた短絡試験において、導通しない電圧を測定することによって得られた値である。
すなわち、本発明のポリオレフィン微多孔膜は、１０ｃｍ×１００ｃｍの試験片について、０．３ｋＶの電圧をかけた際の短絡試験において導通しないポリオレフィン微多孔膜であることが好ましい。 The unit area withstand voltage of the polyolefin microporous membrane of each embodiment of the present invention is preferably 3 kV / m 2 or more, more preferably 4 kV / m 2 or more, and 5 kV / m 2 or more. Is more preferable. Most preferably, it is 6 kV / m 2 or more.
The unit area withstand voltage is a value obtained by measuring a voltage that does not conduct in a short-circuit test in which a voltage is applied to a 10 cm × 100 cm size test piece.
That is, the polyolefin microporous membrane of the present invention is preferably a polyolefin microporous membrane that does not conduct in a short-circuit test when a voltage of 0.3 kV is applied to a 10 cm × 100 cm test piece.
検査の電圧は、高ければ高い程好ましいが、フィルムの膜厚や空孔率等に依存する為、電池の検査電圧である０．３ｋＶが好ましく、より好ましくは、０．４ｋＶであり、さらに好ましくは０．５ｋＶ、もっとも好ましくは０．６ｋＶである。
The inspection voltage is preferably as high as possible. However, since it depends on the film thickness, the porosity, etc., the inspection voltage of the battery is preferably 0.3 kV, more preferably 0.4 kV, and still more preferably. Is 0.5 kV, most preferably 0.6 kV.
検査の面積としては、全数検査が好ましいが、検査に掛かる時間、人員等のコストの面から、０．１０ｍ２が好ましく、より好ましくは０．１５ｍ２、最も好ましくは０．２ｍ２である。
The area of the test, but total inspection is preferred, the time required for testing, the cost of the plane of the personnel, etc., preferably 0.10 m 2, more preferably 0.15 m 2, and most preferably 0.2 m 2.
ポリオレフィン微多孔膜の極大孔径は、０．０５μｍ以上であることが好ましく、０．０８μｍ以上であることがより好ましい。上限は２μｍ以下であることが好ましく、０．５μｍ以下であることがより好ましい。極大孔径が小さ過ぎると、電池用セパレ－タとして使用したときのイオンの移動性が悪く、抵抗が大きくなるので適当でない。また極大孔径が大きすぎると、イオン移動が大きすぎて適当でない。
The maximum pore diameter of the polyolefin microporous membrane is preferably 0.05 μm or more, and more preferably 0.08 μm or more. The upper limit is preferably 2 μm or less, and more preferably 0.5 μm or less. If the maximum pore diameter is too small, the mobility of ions when used as a battery separator is poor and resistance is increased, which is not suitable. On the other hand, if the maximum pore diameter is too large, the ion migration is too large, which is not suitable.
ポリオレフィン微多孔膜が複数枚のフィルムを積層した積層体である場合、フィルム間の層間剥離強度は３～９０ｇ／１５ｍｍであることが好ましく、３～８０ｇ／１５ｍｍであることがより好ましい。層間剥離強度が低いと、例えば電池用セパレ－タの製造工程でフィルム間の剥がれ、カール、伸び等が生じ易く、製品の品質面で問題が生じる恐れがある。
When the polyolefin microporous membrane is a laminate in which a plurality of films are laminated, the delamination strength between the films is preferably 3 to 90 g / 15 mm, and more preferably 3 to 80 g / 15 mm. If the delamination strength is low, for example, in the process of manufacturing a battery separator, peeling between films, curling, elongation and the like are likely to occur, which may cause problems in product quality.
ポリオレフィン微多孔膜をセパレータとして用いる場合、一軸延伸または二軸延伸されたポリオレフィン微多孔膜が好適である。中でも、長手方向（ＭＤ方向）に一軸延伸されたポリオレフィン微多孔膜は、適度な強度を備えつつ幅方向の熱収縮が少ないため、特に好ましい。一軸延伸されたポリオレフィン微多孔膜をセパレータとして用いると、長尺シート状の正極および負極とともに巻回された場合、長手方向の熱収縮も抑制することが可能となる。このため、長手方向に一軸延伸されたポリオレフィン微多孔膜は、巻回された電極体を構成するセパレータとして特に好適である。
When using a polyolefin microporous membrane as a separator, a uniaxially or biaxially stretched polyolefin microporous membrane is preferred. Among these, a polyolefin microporous film uniaxially stretched in the longitudinal direction (MD direction) is particularly preferable because it has moderate strength and has little thermal shrinkage in the width direction. When a uniaxially stretched polyolefin microporous membrane is used as a separator, thermal shrinkage in the longitudinal direction can be suppressed when wound together with a long sheet-like positive electrode and negative electrode. For this reason, the polyolefin microporous film uniaxially stretched in the longitudinal direction is particularly suitable as a separator constituting a wound electrode body.
＜ポリオレフィン微多孔膜の製造方法＞
本発明のポリオレフィン微多孔膜は、製造時に溶媒を使用しない乾式プロセスにて製造されることが好ましい。
湿式法で製造した微多孔膜は除去できない溶媒成分が残留し、可塑剤として働いている為か、メルトダウン温度が向上しない為に好ましくない。 <Method for producing polyolefin microporous membrane>
The polyolefin microporous membrane of the present invention is preferably produced by a dry process that does not use a solvent during production.
A microporous membrane produced by a wet method is not preferable because a solvent component that cannot be removed remains and functions as a plasticizer, or because the meltdown temperature does not increase.
本発明のポリオレフィン微多孔膜は、製造時に溶媒を使用しない乾式プロセスにて製造されることが好ましい。
湿式法で製造した微多孔膜は除去できない溶媒成分が残留し、可塑剤として働いている為か、メルトダウン温度が向上しない為に好ましくない。 <Method for producing polyolefin microporous membrane>
The polyolefin microporous membrane of the present invention is preferably produced by a dry process that does not use a solvent during production.
A microporous membrane produced by a wet method is not preferable because a solvent component that cannot be removed remains and functions as a plasticizer, or because the meltdown temperature does not increase.
以下に上述のポリオレフィン微多孔膜を製造する工程について説明する。
本発明のポリオレフィン微多孔膜は、例えば、原反（前駆体フィルム）の製造工程、ラミネート工程、延伸工程の３つの工程を経ることで製造できる。ポリオレフィン微多孔膜は、２種３層の多層原反製膜装置を用いて３層積層された原反を製造した後に、延伸工程を経ることで製造することもできる。
また、ＰＥ系樹脂やＰＰ系樹脂の単層からなるポリオレフィン微多孔膜を製造する場合、または多層原反製膜装置で製膜した原反を用いてポリオレフィン微多孔膜を製造する場合は、ラミネート工程を省略しても良い。 The process for producing the above-mentioned polyolefin microporous membrane will be described below.
The polyolefin microporous membrane of the present invention can be produced, for example, by going through three steps: a raw fabric (precursor film) production step, a lamination step, and a stretching step. The polyolefin microporous membrane can also be produced by producing an original fabric laminated in three layers using a two-type, three-layer multilayer original fabric forming apparatus, and then performing a stretching process.
In addition, when manufacturing a polyolefin microporous film composed of a single layer of PE-based resin or PP-based resin, or when manufacturing a polyolefin microporous film using an original film formed by a multilayer original film forming apparatus, The process may be omitted.
本発明のポリオレフィン微多孔膜は、例えば、原反（前駆体フィルム）の製造工程、ラミネート工程、延伸工程の３つの工程を経ることで製造できる。ポリオレフィン微多孔膜は、２種３層の多層原反製膜装置を用いて３層積層された原反を製造した後に、延伸工程を経ることで製造することもできる。
また、ＰＥ系樹脂やＰＰ系樹脂の単層からなるポリオレフィン微多孔膜を製造する場合、または多層原反製膜装置で製膜した原反を用いてポリオレフィン微多孔膜を製造する場合は、ラミネート工程を省略しても良い。 The process for producing the above-mentioned polyolefin microporous membrane will be described below.
The polyolefin microporous membrane of the present invention can be produced, for example, by going through three steps: a raw fabric (precursor film) production step, a lamination step, and a stretching step. The polyolefin microporous membrane can also be produced by producing an original fabric laminated in three layers using a two-type, three-layer multilayer original fabric forming apparatus, and then performing a stretching process.
In addition, when manufacturing a polyolefin microporous film composed of a single layer of PE-based resin or PP-based resin, or when manufacturing a polyolefin microporous film using an original film formed by a multilayer original film forming apparatus, The process may be omitted.
［原反の製造工程］
ポリオレフィン微多孔膜を作製するための前駆体フィルムである原反フィルムは、厚みが均一で、複数枚積層させた後に延伸により多孔化する性質を備えていることが好ましい。成形方法は、Ｔダイによる溶融成形が好適であるが、インフレーション法や湿式溶液法等を採用することもできる。
例えば、ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を得るために、別々にフィルムをＴダイによる溶融成形する場合、一般にそれぞれの樹脂の溶融温度の２０℃以上６０℃以下温度で、ドラフト比１０以上１０００以下、好ましくは５０以上５００以下で行なわれる。また引取速度は特に限定はされないが、普通１０ｍ／ｍｉｎ．以上、２００ｍ／ｍｉｎ．以下で成形される。引取速度は、最終的に得られるポリオレフィン微多孔膜の特性（複屈折及び弾性回復率、ポリオレフィン微多孔膜の孔径、空孔率、層間剥離強度、機械的強度等）に影響するので重要である。
また、ポリオレフィン微多孔膜の表面粗さを一定の値以下に抑える為に、原反フィルムの厚みの均一性が重要である。原反の厚みに対する変動係数（Ｃ．Ｖ．）は、０．００１以上、０．０３０以下の範囲に調整することが望ましい。 [Manufacturing process of raw fabric]
The raw film, which is a precursor film for producing a polyolefin microporous film, preferably has a uniform thickness and has a property of being made porous by stretching after being laminated. The molding method is preferably melt molding using a T-die, but an inflation method, a wet solution method, or the like can also be employed.
For example, in order to obtain a polyolefin microporous film in which a PP-based resin and a PE-based resin are laminated, when the films are separately melt-molded by a T-die, the melting temperature of each resin is generally 20 ° C. or higher and 60 ° C. or lower. And a draft ratio of 10 to 1000, preferably 50 to 500. The take-up speed is not particularly limited, but is usually 10 m / min. As described above, 200 m / min. Molded in the following. The take-up speed is important because it affects the final properties of the microporous polyolefin film (birefringence and elastic recovery rate, pore size, porosity, delamination strength, mechanical strength, etc.). .
Moreover, in order to keep the surface roughness of the polyolefin microporous film below a certain value, the uniformity of the thickness of the raw film is important. It is desirable to adjust the coefficient of variation (CV) with respect to the thickness of the original fabric in the range of 0.001 or more and 0.030 or less.
ポリオレフィン微多孔膜を作製するための前駆体フィルムである原反フィルムは、厚みが均一で、複数枚積層させた後に延伸により多孔化する性質を備えていることが好ましい。成形方法は、Ｔダイによる溶融成形が好適であるが、インフレーション法や湿式溶液法等を採用することもできる。
例えば、ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を得るために、別々にフィルムをＴダイによる溶融成形する場合、一般にそれぞれの樹脂の溶融温度の２０℃以上６０℃以下温度で、ドラフト比１０以上１０００以下、好ましくは５０以上５００以下で行なわれる。また引取速度は特に限定はされないが、普通１０ｍ／ｍｉｎ．以上、２００ｍ／ｍｉｎ．以下で成形される。引取速度は、最終的に得られるポリオレフィン微多孔膜の特性（複屈折及び弾性回復率、ポリオレフィン微多孔膜の孔径、空孔率、層間剥離強度、機械的強度等）に影響するので重要である。
また、ポリオレフィン微多孔膜の表面粗さを一定の値以下に抑える為に、原反フィルムの厚みの均一性が重要である。原反の厚みに対する変動係数（Ｃ．Ｖ．）は、０．００１以上、０．０３０以下の範囲に調整することが望ましい。 [Manufacturing process of raw fabric]
The raw film, which is a precursor film for producing a polyolefin microporous film, preferably has a uniform thickness and has a property of being made porous by stretching after being laminated. The molding method is preferably melt molding using a T-die, but an inflation method, a wet solution method, or the like can also be employed.
For example, in order to obtain a polyolefin microporous film in which a PP-based resin and a PE-based resin are laminated, when the films are separately melt-molded by a T-die, the melting temperature of each resin is generally 20 ° C. or higher and 60 ° C. or lower. And a draft ratio of 10 to 1000, preferably 50 to 500. The take-up speed is not particularly limited, but is usually 10 m / min. As described above, 200 m / min. Molded in the following. The take-up speed is important because it affects the final properties of the microporous polyolefin film (birefringence and elastic recovery rate, pore size, porosity, delamination strength, mechanical strength, etc.). .
Moreover, in order to keep the surface roughness of the polyolefin microporous film below a certain value, the uniformity of the thickness of the raw film is important. It is desirable to adjust the coefficient of variation (CV) with respect to the thickness of the original fabric in the range of 0.001 or more and 0.030 or less.
［ラミネート工程］
原反の製造工程により製造された原反であるポリプロピレンフィルムとポリエチレンフィルムを積層する工程について記載する。
ポリプロピレンフィルムとポリエチレンフィルムは、熱圧着によって積層される。複数枚のフィルムは、これを加熱されたロール間を通し熱圧着される。詳細には、フィルムが複数組の原反ロールスタンドから巻きだされ、加熱されたロール間でニップされ圧着されて積層される。積層は、各フィルムの複屈折及び弾性回復率が実質的に低下しないように熱圧着することが必要である。 [Lamination process]
It describes about the process of laminating | stacking the polypropylene film and polyethylene film which are the raw fabric manufactured by the manufacturing process of the raw fabric.
The polypropylene film and the polyethylene film are laminated by thermocompression bonding. The plurality of films are thermocompression bonded through the heated rolls. Specifically, the film is unwound from a plurality of sets of raw roll stands, and is nipped and pressed between the heated rolls to be laminated. Lamination needs to be thermocompression-bonded so that the birefringence and elastic recovery of each film are not substantially reduced.
原反の製造工程により製造された原反であるポリプロピレンフィルムとポリエチレンフィルムを積層する工程について記載する。
ポリプロピレンフィルムとポリエチレンフィルムは、熱圧着によって積層される。複数枚のフィルムは、これを加熱されたロール間を通し熱圧着される。詳細には、フィルムが複数組の原反ロールスタンドから巻きだされ、加熱されたロール間でニップされ圧着されて積層される。積層は、各フィルムの複屈折及び弾性回復率が実質的に低下しないように熱圧着することが必要である。 [Lamination process]
It describes about the process of laminating | stacking the polypropylene film and polyethylene film which are the raw fabric manufactured by the manufacturing process of the raw fabric.
The polypropylene film and the polyethylene film are laminated by thermocompression bonding. The plurality of films are thermocompression bonded through the heated rolls. Specifically, the film is unwound from a plurality of sets of raw roll stands, and is nipped and pressed between the heated rolls to be laminated. Lamination needs to be thermocompression-bonded so that the birefringence and elastic recovery of each film are not substantially reduced.
複数層を熱圧着させる加熱されたロ－ルの温度（熱圧着温度）は、１２０℃以上１６０℃以下であることが好ましく、更に好ましくは１２５℃以上１５０℃以下である。熱圧着温度が低すぎると、フィルム間の剥離強度が弱くなり、その後の延伸工程で剥がれが生じる。逆に熱圧着温度が高すぎると、ポリエチレンフィルムが溶融し、フィルムの複屈折及び弾性回復率が大きく低下し、所期の課題を満たすポリオレフィン微多孔膜は得られない。
また、複数枚の原反を熱圧着した積層フィルムの厚みは、特に制限されないが一般には９μｍ以上、６０μｍ以下が適当である。 The temperature of the heated roll for thermocompression bonding of the plurality of layers (thermocompression bonding temperature) is preferably 120 ° C. or higher and 160 ° C. or lower, more preferably 125 ° C. or higher and 150 ° C. or lower. If the thermocompression bonding temperature is too low, the peel strength between the films becomes weak, and peeling occurs in the subsequent stretching step. On the other hand, if the thermocompression bonding temperature is too high, the polyethylene film is melted, the birefringence and the elastic recovery rate of the film are greatly reduced, and a polyolefin microporous film that satisfies the desired problems cannot be obtained.
The thickness of the laminated film obtained by thermocompression bonding a plurality of original fabrics is not particularly limited, but generally 9 μm or more and 60 μm or less is appropriate.
また、複数枚の原反を熱圧着した積層フィルムの厚みは、特に制限されないが一般には９μｍ以上、６０μｍ以下が適当である。 The temperature of the heated roll for thermocompression bonding of the plurality of layers (thermocompression bonding temperature) is preferably 120 ° C. or higher and 160 ° C. or lower, more preferably 125 ° C. or higher and 150 ° C. or lower. If the thermocompression bonding temperature is too low, the peel strength between the films becomes weak, and peeling occurs in the subsequent stretching step. On the other hand, if the thermocompression bonding temperature is too high, the polyethylene film is melted, the birefringence and the elastic recovery rate of the film are greatly reduced, and a polyolefin microporous film that satisfies the desired problems cannot be obtained.
The thickness of the laminated film obtained by thermocompression bonding a plurality of original fabrics is not particularly limited, but generally 9 μm or more and 60 μm or less is appropriate.
[延伸工程]
積層フィルムは延伸工程にて、各層同時に多孔質化される。
延伸工程は、熱処理ゾーン（オーブン１）、冷延伸ゾーン、熱延伸ゾーン（オーブン２）、熱固定ゾーン（オーブン３）の４つのゾーンにより行われる。 [Stretching process]
The laminated film is made porous at the same time in the stretching process.
The stretching step is performed by four zones: a heat treatment zone (oven 1), a cold stretching zone, a hot stretching zone (oven 2), and a heat setting zone (oven 3).
積層フィルムは延伸工程にて、各層同時に多孔質化される。
延伸工程は、熱処理ゾーン（オーブン１）、冷延伸ゾーン、熱延伸ゾーン（オーブン２）、熱固定ゾーン（オーブン３）の４つのゾーンにより行われる。 [Stretching process]
The laminated film is made porous at the same time in the stretching process.
The stretching step is performed by four zones: a heat treatment zone (oven 1), a cold stretching zone, a hot stretching zone (oven 2), and a heat setting zone (oven 3).
積層フィルムは、延伸される前に熱処理ゾーンにて熱処理される。熱処理は、加熱空気循環オーブンもしくは加熱ロールにより、定長もしくは１０％以下の緊張下で行われる。
ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を製造する場合、熱処理温度は、１１０℃以上、１５０℃以下の範囲が好ましく、１１５℃以上、１４０℃以下の範囲がより好適である。熱処理温度が低いと十分に多孔化せず、また高すぎるとポリエチレンの溶融が生じて不都合である。熱処理時間は３秒以上、３分間以下が好ましい。 The laminated film is heat treated in a heat treatment zone before being stretched. The heat treatment is performed under a constant length or a tension of 10% or less by a heated air circulation oven or a heating roll.
When producing a polyolefin microporous film in which a PP resin and a PE resin are laminated, the heat treatment temperature is preferably in the range of 110 ° C. or more and 150 ° C. or less, more preferably in the range of 115 ° C. or more and 140 ° C. or less. is there. If the heat treatment temperature is low, the film is not sufficiently porous, and if it is too high, polyethylene is melted, which is inconvenient. The heat treatment time is preferably 3 seconds or more and 3 minutes or less.
ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を製造する場合、熱処理温度は、１１０℃以上、１５０℃以下の範囲が好ましく、１１５℃以上、１４０℃以下の範囲がより好適である。熱処理温度が低いと十分に多孔化せず、また高すぎるとポリエチレンの溶融が生じて不都合である。熱処理時間は３秒以上、３分間以下が好ましい。 The laminated film is heat treated in a heat treatment zone before being stretched. The heat treatment is performed under a constant length or a tension of 10% or less by a heated air circulation oven or a heating roll.
When producing a polyolefin microporous film in which a PP resin and a PE resin are laminated, the heat treatment temperature is preferably in the range of 110 ° C. or more and 150 ° C. or less, more preferably in the range of 115 ° C. or more and 140 ° C. or less. is there. If the heat treatment temperature is low, the film is not sufficiently porous, and if it is too high, polyethylene is melted, which is inconvenient. The heat treatment time is preferably 3 seconds or more and 3 minutes or less.
熱処理された積層フィルムは、冷延伸ゾーンにて低温延伸され、次いで熱延伸ゾーンにて高温延伸されて多孔化され、積層多孔質フィルムとされる。ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を製造する場合、いずれか一方の延伸だけではポリプロピレンとポリエチレンが十分に多孔化されなくなり、これを電池用セパレータとして用いた場合の特性が悪くなる。
The heat-treated laminated film is stretched at a low temperature in a cold stretching zone and then stretched at a high temperature in a hot stretching zone to be made porous, thereby forming a laminated porous film. When producing a polyolefin microporous membrane in which PP resin and PE resin are laminated, the properties of polypropylene and polyethylene are not sufficiently made porous by only one of the stretching, and this is used as a battery separator. Becomes worse.
低温延伸の温度は、マイナス２０℃以上、プラス５０℃以下とすることが好ましく、特に２０℃以上、４０℃以下が好ましい。この低温延伸温度が低すぎると作業中にフィルムの破断が生じ易く、好ましくない。一方、低温延伸温度が高すぎると多孔化が不十分になるので好ましくない。低温延伸の倍率（初期延伸倍率）は、３％以上、２００％以下の範囲が好ましく、より好ましくは５％以上、１００％以下の範囲である。低温延伸の倍率が低すぎると、空孔率が小さいものしか得られない。また高すぎると、所定の空孔率と孔径のものが得られなくなる。したがって、上記範囲が適切である。
The temperature of the low temperature stretching is preferably minus 20 ° C. or more and plus 50 ° C. or less, particularly preferably 20 ° C. or more and 40 ° C. or less. If this low temperature stretching temperature is too low, the film is likely to break during the operation, which is not preferable. On the other hand, if the low-temperature stretching temperature is too high, the porosity becomes insufficient, which is not preferable. The low-temperature stretching ratio (initial stretching ratio) is preferably in the range of 3% to 200%, more preferably in the range of 5% to 100%. When the low-temperature stretching ratio is too low, only a low porosity can be obtained. If it is too high, a product having a predetermined porosity and pore size cannot be obtained. Therefore, the above range is appropriate.
低温延伸した積層フィルムは、次いで熱延伸ゾーンで高温延伸される。高温延伸の温度は、７０℃以上、１５０℃以下とすることが好ましく、特に８０℃以上、１４５℃以下が好ましい。この範囲を外れると十分な多孔化がされないので適当でない。高温延伸の倍率（最大延伸倍率）は、１００％以上、４００％以下の範囲であることが好ましい。高温延伸の倍率が低すぎると、透気度が低く、また高すぎると、透気度が高くなりすぎるので上記範囲が好適である。
The laminated film that has been stretched at a low temperature is then stretched at a high temperature in a hot stretching zone. The high temperature stretching temperature is preferably 70 ° C. or higher and 150 ° C. or lower, and particularly preferably 80 ° C. or higher and 145 ° C. or lower. If it is out of this range, it is not suitable because sufficient porosity is not achieved. The high-temperature stretching ratio (maximum stretching ratio) is preferably in the range of 100% to 400%. If the hot stretching ratio is too low, the air permeability is low, and if it is too high, the air permeability becomes too high, so the above range is suitable.
低温延伸と高温延伸をした後、オーブンで熱緩和工程を行うことが好ましい。熱緩和工程は、延伸時に作用した応力残留によるフィルムの延伸方向への収縮を防ぐために行う。熱緩和工程では、例えば、予め延伸後のフィルム長さが１０％以上、３００％以下の範囲で減少する程度に熱収縮させ、最終延伸倍率とする。熱緩和工程の温度は、７０℃以上、１４５℃以下とすることが好ましく、特に８０℃以上、１４０℃以下が好ましい。
ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を製造する場合、熱緩和工程の温度が高すぎると、ＰＥ層が融解してしまい不都合である。一方、熱間和工程の温度が低すぎると熱緩和が十分でなく、ポリオレフィン微多孔膜の熱収縮率が高くなり好ましくない。また、熱緩和工程を行わないとポリオレフィン微多孔膜の熱収縮率が大きくなり、蓄電デバイス用セパレータとして好ましくない。 It is preferable to perform the thermal relaxation process in an oven after the low temperature stretching and the high temperature stretching. The thermal relaxation process is performed in order to prevent shrinkage in the stretching direction of the film due to residual stress acting during stretching. In the thermal relaxation step, for example, the film length after stretching is preliminarily contracted to such an extent that the film length decreases within a range of 10% or more and 300% or less to obtain the final stretching ratio. The temperature of the thermal relaxation step is preferably 70 ° C. or higher and 145 ° C. or lower, and particularly preferably 80 ° C. or higher and 140 ° C. or lower.
When producing a polyolefin microporous film in which a PP resin and a PE resin are laminated, if the temperature of the thermal relaxation process is too high, the PE layer melts, which is inconvenient. On the other hand, if the temperature of the hot summing step is too low, thermal relaxation is not sufficient, and the thermal shrinkage rate of the polyolefin microporous membrane is undesirably high. Moreover, if the thermal relaxation process is not performed, the thermal shrinkage rate of the polyolefin microporous film increases, which is not preferable as a separator for an electricity storage device.
ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を製造する場合、熱緩和工程の温度が高すぎると、ＰＥ層が融解してしまい不都合である。一方、熱間和工程の温度が低すぎると熱緩和が十分でなく、ポリオレフィン微多孔膜の熱収縮率が高くなり好ましくない。また、熱緩和工程を行わないとポリオレフィン微多孔膜の熱収縮率が大きくなり、蓄電デバイス用セパレータとして好ましくない。 It is preferable to perform the thermal relaxation process in an oven after the low temperature stretching and the high temperature stretching. The thermal relaxation process is performed in order to prevent shrinkage in the stretching direction of the film due to residual stress acting during stretching. In the thermal relaxation step, for example, the film length after stretching is preliminarily contracted to such an extent that the film length decreases within a range of 10% or more and 300% or less to obtain the final stretching ratio. The temperature of the thermal relaxation step is preferably 70 ° C. or higher and 145 ° C. or lower, and particularly preferably 80 ° C. or higher and 140 ° C. or lower.
When producing a polyolefin microporous film in which a PP resin and a PE resin are laminated, if the temperature of the thermal relaxation process is too high, the PE layer melts, which is inconvenient. On the other hand, if the temperature of the hot summing step is too low, thermal relaxation is not sufficient, and the thermal shrinkage rate of the polyolefin microporous membrane is undesirably high. Moreover, if the thermal relaxation process is not performed, the thermal shrinkage rate of the polyolefin microporous film increases, which is not preferable as a separator for an electricity storage device.
熱延伸ゾーンを経た熱処理フィルムは、次いで熱固定ゾーンにて延伸方向の寸法が変化しないように規制して加熱処理する熱固定を行う。熱固定は加熱空気循環オ－ブンもしくは加熱ロ－ルにより、定長（０％）以上、もしくは１０％以下の緊張下で行われる。
熱固定温度は、１１０℃以上、１５０℃以下とすることが好ましく、１１５℃以上、１４０℃以下の範囲がより好適である。温度が低いと十分な熱固定効果が得られず、ポリオレフィン微多孔膜の熱収縮率が高くなる。また、ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を製造する場合、熱固定温度が高すぎるとポリエチレンの溶融が生じて不都合である。 The heat-treated film that has passed through the heat-stretching zone is then subjected to heat-fixing in which heat-treatment is performed in the heat-setting zone so that the dimensions in the stretching direction are not changed. The heat setting is performed under tension of a fixed length (0%) or more or 10% or less by a heated air circulation oven or a heating roll.
The heat setting temperature is preferably 110 ° C. or more and 150 ° C. or less, and more preferably 115 ° C. or more and 140 ° C. or less. When the temperature is low, a sufficient heat setting effect cannot be obtained, and the heat shrinkage rate of the polyolefin microporous membrane increases. Further, when a polyolefin microporous film in which a PP resin and a PE resin are laminated is produced, if the heat setting temperature is too high, the polyethylene is melted, which is inconvenient.
熱固定温度は、１１０℃以上、１５０℃以下とすることが好ましく、１１５℃以上、１４０℃以下の範囲がより好適である。温度が低いと十分な熱固定効果が得られず、ポリオレフィン微多孔膜の熱収縮率が高くなる。また、ＰＰ系樹脂とＰＥ系樹脂とが積層されたポリオレフィン微多孔膜を製造する場合、熱固定温度が高すぎるとポリエチレンの溶融が生じて不都合である。 The heat-treated film that has passed through the heat-stretching zone is then subjected to heat-fixing in which heat-treatment is performed in the heat-setting zone so that the dimensions in the stretching direction are not changed. The heat setting is performed under tension of a fixed length (0%) or more or 10% or less by a heated air circulation oven or a heating roll.
The heat setting temperature is preferably 110 ° C. or more and 150 ° C. or less, and more preferably 115 ° C. or more and 140 ° C. or less. When the temperature is low, a sufficient heat setting effect cannot be obtained, and the heat shrinkage rate of the polyolefin microporous membrane increases. Further, when a polyolefin microporous film in which a PP resin and a PE resin are laminated is produced, if the heat setting temperature is too high, the polyethylene is melted, which is inconvenient.
本発明においては、厚み精度に優れた原反フィルムを積層し、かつ、延伸、熱緩和後に熱固定を行う。このことで、圧縮の特性に優れ、寸法安定性のよい所期の課題を満たすことができる層間剥離強度の高いポリオレフィン微多孔膜が得られる。
In the present invention, a raw film excellent in thickness accuracy is laminated, and heat setting is performed after stretching and thermal relaxation. As a result, a polyolefin microporous film having high delamination strength that can satisfy the desired problem of excellent compression characteristics and good dimensional stability can be obtained.
ポリオレフィン微多孔膜を製造するには、原反を複数枚別々に製膜して、多層に張り合わせる上記の方法を用いてもよいし、個別の押出機より押し出された樹脂を、ダイの中で合流させ、共に押し出す方法を用いることも可能である。
In order to produce a polyolefin microporous membrane, the above-mentioned method may be used in which a plurality of raw films are separately formed and laminated together, or a resin extruded from an individual extruder is placed in a die. It is also possible to use a method of joining together and extruding together.
図３は、本実施形態のポリオレフィン微多孔膜の一例を説明するための断面模式図である。図３における符号１１は、ポリオレフィン微多孔膜１０に含まれる多数の空孔のうちの一つを示している。図３に示すように、空孔１１は、断面視で厚み方向中心部から表面及び裏面に向かって徐々に直径が小さくなる略円筒状の形状を有する。ポリオレフィン微多孔膜１０に含まれる空孔１１は、表面から見た孔径ｄ１と、極大孔径ｄ２との差が大きい。このことにより、図３に示すポリオレフィン微多孔膜１０では、空孔率よりも表面開口率が小さくなっている。
FIG. 3 is a schematic cross-sectional view for explaining an example of the polyolefin microporous membrane of the present embodiment. Reference numeral 11 in FIG. 3 indicates one of a large number of pores included in the polyolefin microporous membrane 10. As shown in FIG. 3, the hole 11 has a substantially cylindrical shape whose diameter gradually decreases from the central portion in the thickness direction toward the front surface and the back surface in a cross-sectional view. The pores 11 contained in the polyolefin microporous membrane 10 have a large difference between the pore diameter d1 viewed from the surface and the maximum pore diameter d2. Thereby, in the microporous polyolefin membrane 10 shown in FIG. 3, the surface opening ratio is smaller than the porosity.
図３に示すポリオレフィン微多孔膜１０は、空孔率が４０～７０％であり、表面開口率が１０～３０％の模式図である。空孔率が４０％以上であって表面開口率が１０％以上であると、これを蓄電デバイスのセパレータとして用いた場合に電解質を十分に保持できるため、好ましい。空孔率は５０％以上であることがより好ましい。表面開口率は１２％以上であることがより好ましい。
また、空孔率が７０％以下であって表面開口率が３０％以下であると、これを蓄電デバイスのセパレータとして用いた場合に、セパレータを介した短絡を効果的に防止でき、好ましい。また、空孔率は６０％以下であることがより好ましい。表面開口率は２５％以下であることが更に好ましい。 Thepolyolefin microporous membrane 10 shown in FIG. 3 is a schematic diagram having a porosity of 40 to 70% and a surface opening ratio of 10 to 30%. When the porosity is 40% or more and the surface opening ratio is 10% or more, the electrolyte can be sufficiently retained when this is used as a separator of an electricity storage device, which is preferable. The porosity is more preferably 50% or more. The surface aperture ratio is more preferably 12% or more.
Moreover, when the porosity is 70% or less and the surface opening ratio is 30% or less, when this is used as a separator of an electricity storage device, a short circuit through the separator can be effectively prevented, which is preferable. Further, the porosity is more preferably 60% or less. The surface aperture ratio is more preferably 25% or less.
また、空孔率が７０％以下であって表面開口率が３０％以下であると、これを蓄電デバイスのセパレータとして用いた場合に、セパレータを介した短絡を効果的に防止でき、好ましい。また、空孔率は６０％以下であることがより好ましい。表面開口率は２５％以下であることが更に好ましい。 The
Moreover, when the porosity is 70% or less and the surface opening ratio is 30% or less, when this is used as a separator of an electricity storage device, a short circuit through the separator can be effectively prevented, which is preferable. Further, the porosity is more preferably 60% or less. The surface aperture ratio is more preferably 25% or less.
図４は、従来のポリオレフィン微多孔膜を説明するための断面模式図である。図４における符号２１は、ポリオレフィン微多孔膜２０に含まれる多数の空孔のうちの一つを示している。図４に示す空孔２１も、図３に示す空孔１１と同様に、断面視で厚み方向中心部から表面及び裏面に向かって徐々に直径が小さくなる略円筒状の形状を有する。
しかし、図４に示す従来のポリオレフィン微多孔膜２０は、蓄電デバイスのセパレータとして用いた場合に、電解質を十分に保持でき、かつ、セパレータを介した短絡を効果的に防止できるものではなかった。 FIG. 4 is a schematic cross-sectional view for explaining a conventional polyolefin microporous membrane.Reference numeral 21 in FIG. 4 indicates one of a large number of pores included in the polyolefin microporous membrane 20. As with the hole 11 shown in FIG. 3, the hole 21 shown in FIG. 4 has a substantially cylindrical shape whose diameter gradually decreases from the central portion in the thickness direction toward the front and back surfaces in a cross-sectional view.
However, when the conventionalpolyolefin microporous membrane 20 shown in FIG. 4 is used as a separator for an electricity storage device, it cannot sufficiently hold the electrolyte and cannot effectively prevent a short circuit through the separator.
しかし、図４に示す従来のポリオレフィン微多孔膜２０は、蓄電デバイスのセパレータとして用いた場合に、電解質を十分に保持でき、かつ、セパレータを介した短絡を効果的に防止できるものではなかった。 FIG. 4 is a schematic cross-sectional view for explaining a conventional polyolefin microporous membrane.
However, when the conventional
それは、図４に示す空孔２１の表面から見た孔径ｄ３と、極大孔径ｄ４との差が、図３に示す空孔１１と比較して小さいためである。すなわち、図４に示すポリオレフィン微多孔膜２０では、蓄電デバイスのセパレータとして用いた場合に電解質を十分に保持できる空孔率にすると、表面開口率が大きくなりすぎてセパレータを介した短絡を十分に防止できなくなる。
This is because the difference between the hole diameter d3 viewed from the surface of the hole 21 shown in FIG. 4 and the maximum hole diameter d4 is smaller than that of the hole 11 shown in FIG. That is, in the polyolefin microporous membrane 20 shown in FIG. 4, when the porosity is sufficient to hold the electrolyte when used as a separator of an electricity storage device, the surface opening ratio becomes too large and a short circuit through the separator is sufficiently prevented. It cannot be prevented.
図３に示すポリオレフィン微多孔膜１０に含まれるポリプロピレン系樹脂（ＰＰ系樹脂）の重量平均分子量は、５０万以上８０万以下であることが好ましい。重量平均分子量の下限は５４万以上がより好ましく、５５万以上が最も好ましい。さらに重量平均分子量の上限は７５万以下であることがより好ましく、７０万以下であることが最も好ましい。ＰＰ系樹脂の重量平均分子量が５０万以上８０万以下であると、後述する製造方法により、空孔率が４０～７０％、表面開口率が１０～３０％である図３に示すポリオレフィン微多孔膜１０を容易に製造することができる。
The weight average molecular weight of the polypropylene resin (PP resin) contained in the polyolefin microporous membrane 10 shown in FIG. 3 is preferably 500,000 or more and 800,000 or less. The lower limit of the weight average molecular weight is more preferably 540,000 or more, and most preferably 550,000 or more. Furthermore, the upper limit of the weight average molecular weight is more preferably 750,000 or less, and most preferably 700,000 or less. When the weight average molecular weight of the PP resin is 500,000 or more and 800,000 or less, the polyolefin microporous structure shown in FIG. 3 has a porosity of 40 to 70% and a surface opening ratio of 10 to 30% by the manufacturing method described later. The membrane 10 can be easily manufactured.
図３に示すポリオレフィン微多孔膜１０は、ＰＰ系樹脂のみからなる単層膜、またはＰＰ系樹脂のみから構成される層を表層とした複層膜であることが好ましい。
以下、図３に示すポリオレフィン微多孔膜１０がＰＰ系樹脂のみからなる場合の製造法について、詳細に説明する。
ＰＰ系樹脂のみからなるポリオレフィン微多孔膜１０を製造するには、上述したポリオレフィン微多孔膜の製造方法と同様に、溶媒を使用しない乾式プロセスを用いることが好ましい。図３に示すポリオレフィン微多孔膜１０は、例えば、ＰＰ原反フィルム（前駆体フィルム）の製造工程と延伸工程とを経ることで製造できる。 Thepolyolefin microporous membrane 10 shown in FIG. 3 is preferably a single layer film made of only a PP-based resin or a multilayer film having a layer composed only of a PP-based resin as a surface layer.
Hereinafter, a manufacturing method in the case where thepolyolefin microporous membrane 10 shown in FIG. 3 is made of only a PP resin will be described in detail.
In order to produce thepolyolefin microporous membrane 10 made only of the PP resin, it is preferable to use a dry process that does not use a solvent, as in the method for producing a polyolefin microporous membrane described above. The polyolefin microporous membrane 10 shown in FIG. 3 can be manufactured, for example, through a PP raw film (precursor film) manufacturing process and a stretching process.
以下、図３に示すポリオレフィン微多孔膜１０がＰＰ系樹脂のみからなる場合の製造法について、詳細に説明する。
ＰＰ系樹脂のみからなるポリオレフィン微多孔膜１０を製造するには、上述したポリオレフィン微多孔膜の製造方法と同様に、溶媒を使用しない乾式プロセスを用いることが好ましい。図３に示すポリオレフィン微多孔膜１０は、例えば、ＰＰ原反フィルム（前駆体フィルム）の製造工程と延伸工程とを経ることで製造できる。 The
Hereinafter, a manufacturing method in the case where the
In order to produce the
［ＰＰ原反の製造工程］
既に原反フィルムの製造方法については一通り説明しているが、とりわけＰＰ原反フィルム（以降、ＰＰ原反という）の製造方法について以下に記載する。
図３に示すポリオレフィン微多孔膜１０の素材として用いるＰＰ原反は、公知の方法および条件を用いて製造できる。具体的には、ＰＰ原反の製造方法として、Ｔダイによる溶融成形法、インフレーション法、湿式溶液法等が挙げられる。
図３に示すポリオレフィン微多孔膜１０を製造する場合、乾式法でＴダイを用いて押出する方法によりＰＰ原反を製造することが好ましい。
ＰＰ原反の厚さは、製造するポリオレフィン微多孔膜１０の厚さと、後述する低温延伸および高温延伸の倍率とに応じて決定することができ、特に限定されない。また、ＰＰ原反の弾性回復率を９０％以下にすることにより、この原反を延伸して形成した微多孔膜の強度を高めることが可能となる。 [Manufacturing process of PP original fabric]
Although the manufacturing method of the original film has already been explained, the manufacturing method of the PP original film (hereinafter referred to as PP original film) will be described below.
The PP raw material used as the raw material of thepolyolefin microporous membrane 10 shown in FIG. 3 can be produced using known methods and conditions. Specifically, a PP raw material manufacturing method includes a melt molding method using a T die, an inflation method, a wet solution method, and the like.
When thepolyolefin microporous membrane 10 shown in FIG. 3 is manufactured, it is preferable to manufacture the PP raw material by a method of extruding using a T die by a dry method.
The thickness of the PP original fabric can be determined according to the thickness of thepolyolefin microporous membrane 10 to be produced and the magnification of low-temperature stretching and high-temperature stretching described later, and is not particularly limited. Further, by setting the elastic recovery rate of the PP original fabric to 90% or less, the strength of the microporous film formed by stretching the original fabric can be increased.
既に原反フィルムの製造方法については一通り説明しているが、とりわけＰＰ原反フィルム（以降、ＰＰ原反という）の製造方法について以下に記載する。
図３に示すポリオレフィン微多孔膜１０の素材として用いるＰＰ原反は、公知の方法および条件を用いて製造できる。具体的には、ＰＰ原反の製造方法として、Ｔダイによる溶融成形法、インフレーション法、湿式溶液法等が挙げられる。
図３に示すポリオレフィン微多孔膜１０を製造する場合、乾式法でＴダイを用いて押出する方法によりＰＰ原反を製造することが好ましい。
ＰＰ原反の厚さは、製造するポリオレフィン微多孔膜１０の厚さと、後述する低温延伸および高温延伸の倍率とに応じて決定することができ、特に限定されない。また、ＰＰ原反の弾性回復率を９０％以下にすることにより、この原反を延伸して形成した微多孔膜の強度を高めることが可能となる。 [Manufacturing process of PP original fabric]
Although the manufacturing method of the original film has already been explained, the manufacturing method of the PP original film (hereinafter referred to as PP original film) will be described below.
The PP raw material used as the raw material of the
When the
The thickness of the PP original fabric can be determined according to the thickness of the
ＰＰ原反の複屈折は、１５．０×１０－３～１７．０×１０－３であることが好ましい。ＰＰ原反の複屈折が上記範囲であると、空孔率が４０～７０％、表面開口率が１０～３０％のポリオレフィン微多孔膜１０が得られやすく、好ましい。
ＰＰ原反の弾性回復率は、９０％以下であることが好ましい。ＰＰ原反の弾性回復率が上記範囲であると、空孔率が４０～７０％、表面開口率が１０～３０％のポリオレフィン微多孔膜１０が得られやすく好ましい。また、ＰＰ原反を用いて製造した微多孔膜の強度が高いものとなり、好ましい。 The birefringence of the PP original fabric is preferably 15.0 × 10 −3 to 17.0 × 10 −3 . When the birefringence of the PP raw fabric is in the above range, apolyolefin microporous film 10 having a porosity of 40 to 70% and a surface opening ratio of 10 to 30% is easily obtained, which is preferable.
The elastic recovery rate of the PP original fabric is preferably 90% or less. When the elastic recovery rate of the PP raw material is in the above range, it is preferable that thepolyolefin microporous membrane 10 having a porosity of 40 to 70% and a surface opening ratio of 10 to 30% is easily obtained. Moreover, the strength of the microporous membrane produced using the PP raw material becomes high, which is preferable.
ＰＰ原反の弾性回復率は、９０％以下であることが好ましい。ＰＰ原反の弾性回復率が上記範囲であると、空孔率が４０～７０％、表面開口率が１０～３０％のポリオレフィン微多孔膜１０が得られやすく好ましい。また、ＰＰ原反を用いて製造した微多孔膜の強度が高いものとなり、好ましい。 The birefringence of the PP original fabric is preferably 15.0 × 10 −3 to 17.0 × 10 −3 . When the birefringence of the PP raw fabric is in the above range, a
The elastic recovery rate of the PP original fabric is preferably 90% or less. When the elastic recovery rate of the PP raw material is in the above range, it is preferable that the
[延伸工程]
次に、ＰＰ原反から巻き出した原反フィルムを一軸延伸して多孔質化する。
延伸工程は、従来公知の方法および条件で行うことができ、例えば、上述したポリオレフィン微多孔膜の製造方法と同様にして行うことができる。
以上の工程により、空孔率が４０～７０％、表面開口率が１０～３０％のＰＰ系樹脂のみからなるポリオレフィン微多孔膜１０が得られる。 [Stretching process]
Next, the original film unwound from the PP original is uniaxially stretched to make it porous.
The stretching step can be performed by a conventionally known method and conditions. For example, the stretching step can be performed in the same manner as the method for producing a polyolefin microporous film described above.
Through the above steps, apolyolefin microporous membrane 10 made only of a PP resin having a porosity of 40 to 70% and a surface opening ratio of 10 to 30% is obtained.
次に、ＰＰ原反から巻き出した原反フィルムを一軸延伸して多孔質化する。
延伸工程は、従来公知の方法および条件で行うことができ、例えば、上述したポリオレフィン微多孔膜の製造方法と同様にして行うことができる。
以上の工程により、空孔率が４０～７０％、表面開口率が１０～３０％のＰＰ系樹脂のみからなるポリオレフィン微多孔膜１０が得られる。 [Stretching process]
Next, the original film unwound from the PP original is uniaxially stretched to make it porous.
The stretching step can be performed by a conventionally known method and conditions. For example, the stretching step can be performed in the same manner as the method for producing a polyolefin microporous film described above.
Through the above steps, a
図３に示すポリオレフィン微多孔膜１０は、ポリプロピレン系樹脂を含み、メルトダウン温度が１９５℃以上２３０℃以下であるので、これを蓄電デバイスのセパレータとして用いた場合に、優れた安全性が得られる。しかも、図３に示すポリオレフィン微多孔膜１０は、空孔率が４０～７０％、表面開口率が１０～３０％である。このため、これを蓄電デバイスのセパレータとして用いた場合に、電解質を十分に保持できるとともに、セパレータを介した短絡を効果的に防止できる。
さらに、図３に示すポリオレフィン微多孔膜１０に含まれるポリプロピレン系樹脂が、重量平均分子量５０万以上８０万以下である場合、上記の製造方法により、空孔率が４０～７０％、表面開口率が１０～３０％である図３に示すポリオレフィン微多孔膜１０を容易に製造できる。 Since thepolyolefin microporous membrane 10 shown in FIG. 3 contains a polypropylene resin and has a meltdown temperature of 195 ° C. or higher and 230 ° C. or lower, excellent safety can be obtained when this is used as a separator for an electricity storage device. . Moreover, the polyolefin microporous membrane 10 shown in FIG. 3 has a porosity of 40 to 70% and a surface aperture ratio of 10 to 30%. For this reason, when this is used as a separator of an electrical storage device, while being able to hold electrolyte enough, a short circuit via a separator can be prevented effectively.
Further, when the polypropylene resin contained in thepolyolefin microporous membrane 10 shown in FIG. 3 has a weight average molecular weight of 500,000 or more and 800,000 or less, the porosity is 40 to 70% and the surface area ratio is increased by the above production method. The polyolefin microporous membrane 10 shown in FIG. 3 having a content of 10 to 30% can be easily produced.
さらに、図３に示すポリオレフィン微多孔膜１０に含まれるポリプロピレン系樹脂が、重量平均分子量５０万以上８０万以下である場合、上記の製造方法により、空孔率が４０～７０％、表面開口率が１０～３０％である図３に示すポリオレフィン微多孔膜１０を容易に製造できる。 Since the
Further, when the polypropylene resin contained in the
（蓄電デバイス用セパレータフィルム）
本発明の蓄電デバイス用セパレータフィルムは、本発明のポリオレフィン微多孔膜を有する。
本発明の一実施態様の蓄電デバイス用セパレータフィルムは、本発明のポリオレフィン微多孔膜のみからなることができる。すなわち、本発明のポリオレフィン微多孔膜は、特に追加加工せず、そのまま、蓄電デバイス用セパレータフィルムとして用いることができる。 (Separator film for electricity storage devices)
The separator film for an electricity storage device of the present invention has the polyolefin microporous film of the present invention.
The separator film for an electricity storage device of one embodiment of the present invention can be composed of only the polyolefin microporous film of the present invention. That is, the polyolefin microporous membrane of the present invention can be used as it is as a separator film for an electricity storage device without any additional processing.
本発明の蓄電デバイス用セパレータフィルムは、本発明のポリオレフィン微多孔膜を有する。
本発明の一実施態様の蓄電デバイス用セパレータフィルムは、本発明のポリオレフィン微多孔膜のみからなることができる。すなわち、本発明のポリオレフィン微多孔膜は、特に追加加工せず、そのまま、蓄電デバイス用セパレータフィルムとして用いることができる。 (Separator film for electricity storage devices)
The separator film for an electricity storage device of the present invention has the polyolefin microporous film of the present invention.
The separator film for an electricity storage device of one embodiment of the present invention can be composed of only the polyolefin microporous film of the present invention. That is, the polyolefin microporous membrane of the present invention can be used as it is as a separator film for an electricity storage device without any additional processing.
本発明のその他の実施態様の蓄電デバイス用セパレータフィルムは、本発明のポリオレフィン微多孔膜を用いた蓄電デバイス用セパレータフィルムとして、ポリオレフィン微多孔膜の片面もしくは両面に、耐熱多孔質層、接着層、機能層から選ばれる少なくとも１層を有していても良い。これらの耐熱多孔質層、接着層、機能層は、各単層で配置されても良く、複数層積層されても良い。
これらの層の形成方法として、複数回の塗工で積層させても良いが、混合等により複数の機能を持たせた層を配置しても良い。たとえば、特許文献３に記載の公知の手法を用いる事ができる。 The separator film for an electricity storage device of another embodiment of the present invention is a heat resistant porous layer, an adhesive layer, on one or both sides of the polyolefin microporous membrane, as a separator film for an electricity storage device using the polyolefin microporous membrane of the present invention. You may have at least 1 layer chosen from a functional layer. These heat-resistant porous layer, adhesive layer, and functional layer may be arranged as a single layer, or a plurality of layers may be laminated.
As a method for forming these layers, the layers may be laminated by a plurality of coatings, or a layer having a plurality of functions may be arranged by mixing or the like. For example, a known method described inPatent Document 3 can be used.
これらの層の形成方法として、複数回の塗工で積層させても良いが、混合等により複数の機能を持たせた層を配置しても良い。たとえば、特許文献３に記載の公知の手法を用いる事ができる。 The separator film for an electricity storage device of another embodiment of the present invention is a heat resistant porous layer, an adhesive layer, on one or both sides of the polyolefin microporous membrane, as a separator film for an electricity storage device using the polyolefin microporous membrane of the present invention. You may have at least 1 layer chosen from a functional layer. These heat-resistant porous layer, adhesive layer, and functional layer may be arranged as a single layer, or a plurality of layers may be laminated.
As a method for forming these layers, the layers may be laminated by a plurality of coatings, or a layer having a plurality of functions may be arranged by mixing or the like. For example, a known method described in
耐熱多孔質層は、本発明の微多孔膜の片面もしくは両面に、耐熱性微粒子と有機バインダを混合し塗工する工程を経る等の手法にて付与してもよい。さらに、耐熱多孔質層の上に、フッ素系樹脂等の有機物を塗工して接着層を付与しても良い。さらに、接着層の上に、有機微粒子等とバインダを混合して、塗工する工程を経る手法にて、機能層を付与しても良い。
The heat resistant porous layer may be applied to one surface or both surfaces of the microporous membrane of the present invention by a method such as a process of mixing and applying heat resistant fine particles and an organic binder. Furthermore, an adhesive layer may be provided by coating an organic material such as a fluorine-based resin on the heat-resistant porous layer. Furthermore, a functional layer may be provided on the adhesive layer by a method in which organic fine particles and a binder are mixed and applied.
［耐熱多孔質層］
以下に、耐熱多孔質層について詳述する。
耐熱多孔質層は、耐熱性微粒子を含有することで、その耐熱性を確保している。なお「耐熱性」とは、少なくとも１５０℃において変形などの形状変化が目視で確認されないことを意味する。耐熱性微粒子の有する耐熱性は、２００℃以上であることが好ましく、３００℃以上であることがより好ましく、４００℃以上であることが更に好ましい。また、耐熱多孔質層は単層であってもよいし複数の層が積層された多層であってもよい。 [Heat resistant porous layer]
The heat resistant porous layer will be described in detail below.
The heat-resistant porous layer ensures heat resistance by containing heat-resistant fine particles. “Heat resistance” means that no shape change such as deformation is visually confirmed at least at 150 ° C. The heat resistance of the heat-resistant fine particles is preferably 200 ° C. or higher, more preferably 300 ° C. or higher, and still more preferably 400 ° C. or higher. The heat resistant porous layer may be a single layer or a multilayer in which a plurality of layers are laminated.
以下に、耐熱多孔質層について詳述する。
耐熱多孔質層は、耐熱性微粒子を含有することで、その耐熱性を確保している。なお「耐熱性」とは、少なくとも１５０℃において変形などの形状変化が目視で確認されないことを意味する。耐熱性微粒子の有する耐熱性は、２００℃以上であることが好ましく、３００℃以上であることがより好ましく、４００℃以上であることが更に好ましい。また、耐熱多孔質層は単層であってもよいし複数の層が積層された多層であってもよい。 [Heat resistant porous layer]
The heat resistant porous layer will be described in detail below.
The heat-resistant porous layer ensures heat resistance by containing heat-resistant fine particles. “Heat resistance” means that no shape change such as deformation is visually confirmed at least at 150 ° C. The heat resistance of the heat-resistant fine particles is preferably 200 ° C. or higher, more preferably 300 ° C. or higher, and still more preferably 400 ° C. or higher. The heat resistant porous layer may be a single layer or a multilayer in which a plurality of layers are laminated.
耐熱性微粒子としては、電気絶縁性を有する無機微粒子であることが好ましく、具体的には、酸化鉄、シリカ（ＳｉＯ２）、アルミナ（Ａｌ２Ｏ３）、ＴｉＯ２、マグネシア、ベーマイト、ＢａＴｉＯ２などの無機酸化物微粒子；窒化アルミニウム、窒化ケイ素などの無機窒化物微粒子；フッ化カルシウム、フッ化バリウム、硫酸バリウムなどの難溶性のイオン結晶微粒子；シリコン、ダイヤモンドなどの共有結合性結晶微粒子；モンモリロナイトなどの粘土微粒子；などが挙げられる。ここで、前記無機酸化物微粒子は、ベーマイト、ゼオライト、アパタイト、カオリン、ムライト、スピネル、オリビン、マイカなどの鉱物資源由来物質またはこれらの人造物などの微粒子であってもよい。また、これらの無機微粒子を構成する無機化合物は、必要に応じて、元素置換されていたり、固溶体化されていたりしてもよい。更に前記の無機微粒子は表面処理が施されていてもよい。また、無機微粒子は、金属、ＳｎＯ２、スズ－インジウム酸化物（ＩＴＯ）などの導電性酸化物、カーボンブラック、グラファイトなどの炭素質材料などで例示される導電性材料の表面を、電気絶縁性を有する材料（例えば、前記の無機酸化物など）で被覆することにより電気絶縁性を持たせた粒子であってもよい。
The heat-resistant fine particles are preferably inorganic fine particles having electrical insulating properties, and specifically, iron oxide, silica (SiO 2 ), alumina (Al 2 O 3 ), TiO 2 , magnesia, boehmite, BaTiO 2. Inorganic oxide fine particles such as aluminum nitride, silicon nitride, etc .; sparingly soluble ionic crystal fine particles such as calcium fluoride, barium fluoride, and barium sulfate; covalently bonded crystal fine particles such as silicon and diamond; montmorillonite Clay fine particles such as; Here, the inorganic oxide fine particles may be fine particles such as boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, mica, or a mineral resource-derived material or an artificial product thereof. Moreover, the inorganic compound which comprises these inorganic fine particles may be element-substituted, or may be made into a solid solution as needed. Further, the inorganic fine particles may be subjected to a surface treatment. In addition, the inorganic fine particles are formed by electrically insulating the surface of a conductive material exemplified by metals, conductive oxides such as SnO 2 and tin-indium oxide (ITO), carbonaceous materials such as carbon black and graphite. It is also possible to use particles that are made electrically insulating by coating with a material having the above (for example, the above-mentioned inorganic oxide).
また、耐熱性微粒子として有機微粒子を用いてもよい。有機微粒子の具体例としては、ポリイミド、メラミン系樹脂、フェノール系樹脂、芳香族ポリアミド樹脂、架橋ポリメチルメタクリレート（架橋ＰＭＭＡ）、架橋ポリスチレン（架橋ＰＳ）、ポリジビニルベンゼン（ＰＤＶＢ）、ベンゾグアナミン－ホルムアルデヒド縮合物などの架橋高分子の微粒子；熱可塑性ポリイミドなどの耐熱性高分子の微粒子；が挙げられる。これらの有機微粒子を構成する有機樹脂（高分子）は、前記例示の材料の混合物、変性体、誘導体、共重合体（ランダム共重合体、交互共重合体、ブロック共重合体、グラフト共重合体）、架橋体（前記の耐熱性高分子の場合）であってもよい。
Moreover, organic fine particles may be used as the heat-resistant fine particles. Specific examples of the organic fine particles include polyimide, melamine resin, phenol resin, aromatic polyamide resin, crosslinked polymethyl methacrylate (crosslinked PMMA), crosslinked polystyrene (crosslinked PS), polydivinylbenzene (PDVB), benzoguanamine-formaldehyde condensation. Fine particles of a crosslinked polymer such as a product; and fine particles of a heat resistant polymer such as a thermoplastic polyimide. The organic resin (polymer) constituting these organic fine particles is a mixture, modified body, derivative, copolymer (random copolymer, alternating copolymer, block copolymer, graft copolymer) of the materials exemplified above. ) Or a crosslinked product (in the case of the heat-resistant polymer).
耐熱性微粒子は、前記例示のものを１種単独で使用してもよく、２種以上を併用してもよい。耐熱性微粒子は上記のとおり無機微粒子および有機微粒子を用いることができるが、用途に応じて適宜使い分けるとよい。
耐熱性微粒子としては、特に、ベーマイトを用いることが好ましい。例えばベーマイトとしては、平均粒径で、好ましくは０．００１μｍ以上、より好ましくは０．１μｍ以上であって、好ましくは１５μｍ以下、より好ましくは３μｍ以下のものが用いられる。
なお、耐熱性微粒子の平均粒径は、例えば、レーザー散乱粒度分布計（例えば、ＨＯＲＩＢＡ社製「ＬＡ－９２０」）を用い、耐熱性微粒子を溶解しない媒体に分散させて測定した数平均粒子径として規定できる。
耐熱性微粒子の形状は、例えば、球状に近い形状であってもよいし、板状であってもよい。短絡防止の点から、耐熱性微粒子は板状の粒子であることが好ましい。板状に形成された耐熱性微粒子の代表的な例としては、アルミナやベーマイトなどが挙げられる。 As the heat-resistant fine particles, those exemplified above may be used alone, or two or more kinds may be used in combination. As the heat-resistant fine particles, inorganic fine particles and organic fine particles can be used as described above.
In particular, boehmite is preferably used as the heat-resistant fine particles. For example, boehmite having an average particle diameter of preferably 0.001 μm or more, more preferably 0.1 μm or more, preferably 15 μm or less, more preferably 3 μm or less is used.
The average particle diameter of the heat-resistant fine particles is, for example, a number average particle diameter measured by dispersing the heat-resistant fine particles in a medium that does not dissolve using a laser scattering particle size distribution analyzer (for example, “LA-920” manufactured by HORIBA). Can be defined as
The shape of the heat-resistant fine particles may be, for example, a nearly spherical shape or a plate shape. From the viewpoint of short circuit prevention, the heat-resistant fine particles are preferably plate-like particles. Typical examples of the heat-resistant fine particles formed in a plate shape include alumina and boehmite.
耐熱性微粒子としては、特に、ベーマイトを用いることが好ましい。例えばベーマイトとしては、平均粒径で、好ましくは０．００１μｍ以上、より好ましくは０．１μｍ以上であって、好ましくは１５μｍ以下、より好ましくは３μｍ以下のものが用いられる。
なお、耐熱性微粒子の平均粒径は、例えば、レーザー散乱粒度分布計（例えば、ＨＯＲＩＢＡ社製「ＬＡ－９２０」）を用い、耐熱性微粒子を溶解しない媒体に分散させて測定した数平均粒子径として規定できる。
耐熱性微粒子の形状は、例えば、球状に近い形状であってもよいし、板状であってもよい。短絡防止の点から、耐熱性微粒子は板状の粒子であることが好ましい。板状に形成された耐熱性微粒子の代表的な例としては、アルミナやベーマイトなどが挙げられる。 As the heat-resistant fine particles, those exemplified above may be used alone, or two or more kinds may be used in combination. As the heat-resistant fine particles, inorganic fine particles and organic fine particles can be used as described above.
In particular, boehmite is preferably used as the heat-resistant fine particles. For example, boehmite having an average particle diameter of preferably 0.001 μm or more, more preferably 0.1 μm or more, preferably 15 μm or less, more preferably 3 μm or less is used.
The average particle diameter of the heat-resistant fine particles is, for example, a number average particle diameter measured by dispersing the heat-resistant fine particles in a medium that does not dissolve using a laser scattering particle size distribution analyzer (for example, “LA-920” manufactured by HORIBA). Can be defined as
The shape of the heat-resistant fine particles may be, for example, a nearly spherical shape or a plate shape. From the viewpoint of short circuit prevention, the heat-resistant fine particles are preferably plate-like particles. Typical examples of the heat-resistant fine particles formed in a plate shape include alumina and boehmite.
耐熱多孔質層は耐熱性微粒子を主成分として含む。なお「主成分として含む」とは、耐熱性微粒子を、耐熱多孔質層の構成成分の全体積中で７０重量％以上含むことを意味する。耐熱多孔質層における耐熱性微粒子の量は、耐熱多孔質層の構成成分の全重量中、８０重量％以上であることが好ましく、８５重量％以上であることがより好ましい。耐熱多孔質層が主成分として耐熱性微粒子を含有することで、ポリオレフィン微多孔膜を含む多孔膜全体の熱収縮を良好に抑制できる。
The heat resistant porous layer contains heat resistant fine particles as a main component. “Containing as a main component” means containing 70% by weight or more of heat-resistant fine particles in the total volume of components of the heat-resistant porous layer. The amount of the heat-resistant fine particles in the heat-resistant porous layer is preferably 80% by weight or more, and more preferably 85% by weight or more, based on the total weight of the components of the heat-resistant porous layer. When the heat-resistant porous layer contains heat-resistant fine particles as a main component, the thermal contraction of the entire porous film including the polyolefin microporous film can be satisfactorily suppressed.
耐熱多孔質層は、例えば主成分として含む耐熱性微粒子同士を結着したり、耐熱性微粒子をポリオレフィン微多孔膜とを結着したりするために、樹脂バインダなどの有機バインダを含有することが好ましい。このような観点から耐熱多孔質層中の耐熱性微粒子量の好適な上限値は、例えば、耐熱多孔質層の構成成分の全重量中、９９重量％であることが好ましい。なお、耐熱多孔質層における耐熱性微粒子の量が少なすぎると、例えば、耐熱多孔質層中の有機バインダ量を多くする必要が生じる。その場合には、耐熱多孔質層の空孔が有機バインダによって埋められてしまい、例えばセパレータとしての機能を喪失するおそれがある。また、開孔剤などを用いて多孔質化した場合には、耐熱性微粒子同士の間隔が大きくなりすぎて、熱収縮を抑制する効果が低下するおそれがある。
The heat-resistant porous layer may contain an organic binder such as a resin binder in order to bind heat-resistant fine particles including, for example, main components or to bind the heat-resistant fine particles to the polyolefin microporous film. preferable. From such a viewpoint, a suitable upper limit value of the amount of heat-resistant fine particles in the heat-resistant porous layer is preferably 99% by weight in the total weight of the constituent components of the heat-resistant porous layer, for example. If the amount of heat-resistant fine particles in the heat-resistant porous layer is too small, for example, it becomes necessary to increase the amount of organic binder in the heat-resistant porous layer. In that case, the pores of the heat-resistant porous layer are filled with the organic binder, and for example, the function as a separator may be lost. Moreover, when making it porous using a pore opening agent etc., the space | interval of heat-resistant fine particles becomes large too much, and there exists a possibility that the effect which suppresses heat shrink may fall.
耐熱多孔質層に用いる有機バインダとしては、耐熱性微粒子同士や耐熱性微粒子とポリオレフィン微多孔膜とを良好に接着でき、かつ電気化学的に安定で、蓄電デバイス用セパレータに使用する場合に電解液に対して安定であれば特に制限はない。
例えば、エチレン－酢酸ビニル共重合体（ＥＶＡ、酢酸ビニル由来の構造単位が２０～３５モル％のもの）、エチレン－エチルアクリレート共重合体などのエチレン－アクリル酸共重合体、フッ素樹脂［ポリフッ化ビニリデン（ＰＶＤＦ）など］、フッ素系ゴム、スチレン－ブタジエンゴム（ＳＢＲ）、カルボキシメチルセルロース（ＣＭＣ）およびヒドロキシエチルセルロース（ＨＥＣ）などの水溶性セルロース誘導体、ポリビニルアルコール（ＰＶＡ）、ポリビニルブチラール（ＰＶＢ）、ポリビニルピロリドン（ＰＶＰ）、ポリＮ－ビニルアセトアミド、架橋アクリル樹脂、ポリウレタン、エポキシ樹脂、ポリイミドなどが挙げられる。これらの有機バインダは１種単独で使用してもよく、２種以上を併用してもよい。 The organic binder used for the heat-resistant porous layer is an electrolyte solution that can adhere well to heat-resistant fine particles or heat-resistant fine particles and a polyolefin microporous film, is electrochemically stable, and is used as a separator for power storage devices. If it is stable, there is no particular limitation.
For example, ethylene-vinyl acetate copolymer (EVA, having a structural unit derived from vinyl acetate of 20 to 35 mol%), ethylene-acrylic acid copolymer such as ethylene-ethyl acrylate copolymer, fluororesin [polyfluoride Vinylidene (PVDF), etc.], fluorine-based rubber, styrene-butadiene rubber (SBR), water-soluble cellulose derivatives such as carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl Examples include pyrrolidone (PVP), poly N-vinylacetamide, cross-linked acrylic resin, polyurethane, epoxy resin, and polyimide. These organic binders may be used alone or in combination of two or more.
例えば、エチレン－酢酸ビニル共重合体（ＥＶＡ、酢酸ビニル由来の構造単位が２０～３５モル％のもの）、エチレン－エチルアクリレート共重合体などのエチレン－アクリル酸共重合体、フッ素樹脂［ポリフッ化ビニリデン（ＰＶＤＦ）など］、フッ素系ゴム、スチレン－ブタジエンゴム（ＳＢＲ）、カルボキシメチルセルロース（ＣＭＣ）およびヒドロキシエチルセルロース（ＨＥＣ）などの水溶性セルロース誘導体、ポリビニルアルコール（ＰＶＡ）、ポリビニルブチラール（ＰＶＢ）、ポリビニルピロリドン（ＰＶＰ）、ポリＮ－ビニルアセトアミド、架橋アクリル樹脂、ポリウレタン、エポキシ樹脂、ポリイミドなどが挙げられる。これらの有機バインダは１種単独で使用してもよく、２種以上を併用してもよい。 The organic binder used for the heat-resistant porous layer is an electrolyte solution that can adhere well to heat-resistant fine particles or heat-resistant fine particles and a polyolefin microporous film, is electrochemically stable, and is used as a separator for power storage devices. If it is stable, there is no particular limitation.
For example, ethylene-vinyl acetate copolymer (EVA, having a structural unit derived from vinyl acetate of 20 to 35 mol%), ethylene-acrylic acid copolymer such as ethylene-ethyl acrylate copolymer, fluororesin [polyfluoride Vinylidene (PVDF), etc.], fluorine-based rubber, styrene-butadiene rubber (SBR), water-soluble cellulose derivatives such as carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl Examples include pyrrolidone (PVP), poly N-vinylacetamide, cross-linked acrylic resin, polyurethane, epoxy resin, and polyimide. These organic binders may be used alone or in combination of two or more.
前記例示の有機バインダの中でも、１５０℃以上の耐熱性を有する耐熱樹脂が好ましく、特に、エチレン－酢酸ビニル共重合体（ＥＶＡ）、エチレン－アクリル酸共重合体、エチレン－エチルアクリレート共重合体（ＥＥＡ）、ポリビニルブチラール（ＰＶＢ）、フッ素系ゴム、スチレン・ブタジエンゴム（ＳＢＲ）などの柔軟性の高い材料がより好ましい。また、アクリル酸ブチルを主成分とし、これを架橋した構造を有する低ガラス転移温度の架橋アクリル樹脂（自己架橋型アクリル樹脂）も好ましい。
Among the organic binders exemplified above, a heat resistant resin having a heat resistance of 150 ° C. or higher is preferable. In particular, an ethylene-vinyl acetate copolymer (EVA), an ethylene-acrylic acid copolymer, an ethylene-ethyl acrylate copolymer ( Highly flexible materials such as EEA), polyvinyl butyral (PVB), fluorine-based rubber, and styrene-butadiene rubber (SBR) are more preferable. A cross-linked acrylic resin (self-crosslinking acrylic resin) having a low glass transition temperature and having a structure in which butyl acrylate is a main component and is cross-linked is also preferable.
耐熱多孔質層における有機バインダの含有量は、耐熱性微粒子１００重量部に対して１．１～３０重量部であることが好ましい。
The content of the organic binder in the heat resistant porous layer is preferably 1.1 to 30 parts by weight with respect to 100 parts by weight of the heat resistant fine particles.
耐熱多孔質層の膜厚は、特に限定されないが、好ましくは０．５μｍ以上であり、より好ましくは１μｍ以上であり、さらに好ましくは２μｍ以上である。耐熱多孔質層の膜厚は１０μｍ以下であることが好ましく、より好ましくは８μｍ以下であり、さらに好ましくは６μｍ以下である。耐熱多孔質層が薄すぎるとメルトダウン防止効果が不十分となる。また、耐熱多孔質層が厚すぎると、例えばセパレータを電池に組み込む工程で耐熱多孔質層にひびが入るなどの欠陥が生じる危険性が高まるので好ましくない。また、耐熱多孔質層が厚すぎると、蓄電デバイス用セパレータとして用いた場合に、電解液の注液量が増加して電池製造コストの増加の一因となること、電池の体積辺りおよび重量当たりのエネルギー密度が低下することから、好ましくない。
The thickness of the heat-resistant porous layer is not particularly limited, but is preferably 0.5 μm or more, more preferably 1 μm or more, and further preferably 2 μm or more. The thickness of the heat resistant porous layer is preferably 10 μm or less, more preferably 8 μm or less, and further preferably 6 μm or less. If the heat-resistant porous layer is too thin, the effect of preventing meltdown will be insufficient. Moreover, it is not preferable that the heat-resistant porous layer is too thick because there is an increased risk of defects such as cracking in the heat-resistant porous layer in the process of incorporating the separator into the battery. Also, if the heat-resistant porous layer is too thick, when used as a separator for an electricity storage device, the amount of electrolyte injected will increase, which will contribute to an increase in battery manufacturing cost, and the per unit volume and weight of the battery. This is not preferable because the energy density decreases.
ポリオレフィン微多孔膜の膜厚と耐熱多孔質層の膜厚との合計は、特に限定されないが、４～４０μｍ、好ましくは９～３０μｍ、更に好ましくは１０～２８μｍである。上記の膜厚が薄すぎると、メルトダウン防止効果が不十分となる上にＬｉデンドライトによる短絡抑止効果も不十分となるので好ましくない。上記の膜厚が厚すぎると、電池セパレータとして使用したとき、電解液の注液量が増加し電池製造コストの増加の一因となること、電池の体積辺りおよび重量当たりのエネルギー密度が低下することから、好ましくない。
The total thickness of the polyolefin microporous film and the heat resistant porous layer is not particularly limited, but is 4 to 40 μm, preferably 9 to 30 μm, and more preferably 10 to 28 μm. If the film thickness is too thin, the effect of preventing meltdown becomes insufficient and the effect of suppressing short-circuiting by Li dendrite becomes insufficient. If the film thickness is too thick, when used as a battery separator, the amount of electrolyte injected will increase, contributing to an increase in battery manufacturing costs, and the energy density per volume and weight of the battery will decrease. Therefore, it is not preferable.
また、ポリオレフィン微多孔膜の平均膜厚をａ（μｍ）、耐熱多孔質層の平均膜厚をｂ（μｍ）としたとき、膜厚比ａ／ｂの値が、０．５以上２０以下であることが好ましく、１以上１０以下であることがより好ましい。ポリオレフィン微多孔膜に対して、耐熱多孔質層の膜厚を厚くすると、電解液の保持率が悪くなってしまう。このため、膜厚比ａ／ｂの値は上記の範囲が好ましい。
Further, when the average film thickness of the polyolefin microporous film is a (μm) and the average film thickness of the heat resistant porous layer is b (μm), the value of the film thickness ratio a / b is 0.5 or more and 20 or less. It is preferable that it is 1 or more and 10 or less. When the thickness of the heat-resistant porous layer is increased with respect to the polyolefin microporous membrane, the retention rate of the electrolytic solution is deteriorated. For this reason, the value of the film thickness ratio a / b is preferably in the above range.
耐熱多孔質層を積層したポリオレフィン微多孔膜のガーレ値（透気度）は、特に限定されないが、８０～７００秒／１００ｃｃ、好ましくは９０～６５０秒／１００ｃｃ、更に好ましくは１００～６００秒／１００ｃｃである。ガーレ値が高すぎると、耐熱多孔質層を積層したポリオレフィン微多孔膜を電池セパレータとして使用したときの機能が十分に得られない虞が生じる。ガーレ値が低すぎると、電池内部の反応の不均一性が高まる危険性があり好ましくない。
The Gurley value (air permeability) of the polyolefin microporous membrane in which the heat-resistant porous layer is laminated is not particularly limited, but is 80 to 700 seconds / 100 cc, preferably 90 to 650 seconds / 100 cc, more preferably 100 to 600 seconds / 100cc. When the Gurley value is too high, there is a possibility that the function when the polyolefin microporous film having the heat resistant porous layer laminated thereon is used as a battery separator cannot be sufficiently obtained. If the Gurley value is too low, there is a risk of increasing the non-uniformity of the reaction inside the battery, which is not preferable.
［耐熱多孔質層の形成方法］
耐熱多孔質層の形成方法は、上記ポリオレフィン微多孔膜の片面または両面に上記耐熱性微粒子を主成分として含む塗工液を塗布する工程と、塗布された塗工液を乾燥して耐熱多孔質層を形成させる工程とを含む。 [Method for forming heat-resistant porous layer]
The method of forming the heat resistant porous layer includes a step of applying a coating liquid containing the heat resistant fine particles as a main component on one or both surfaces of the polyolefin microporous membrane, and drying the applied coating liquid to heat resistant porous Forming a layer.
耐熱多孔質層の形成方法は、上記ポリオレフィン微多孔膜の片面または両面に上記耐熱性微粒子を主成分として含む塗工液を塗布する工程と、塗布された塗工液を乾燥して耐熱多孔質層を形成させる工程とを含む。 [Method for forming heat-resistant porous layer]
The method of forming the heat resistant porous layer includes a step of applying a coating liquid containing the heat resistant fine particles as a main component on one or both surfaces of the polyolefin microporous membrane, and drying the applied coating liquid to heat resistant porous Forming a layer.
耐熱多孔質層が有機バインダを含有する場合には、耐熱多孔質層を形成する塗工液（スラリーなど）の媒体（溶媒）に、有機バインダを溶解させるか、または塗工液中に分散させたエマルジョンの形態とすればよい。
この塗工液は、耐熱性微粒子と必要に応じた量の有機バインダとを含み、これらが水や有機溶剤などの媒体に分散（有機バインダは媒体に溶解してもよい）されたものである。 When the heat-resistant porous layer contains an organic binder, the organic binder is dissolved or dispersed in the coating solution (slurry) medium (solvent) that forms the heat-resistant porous layer. It may be in the form of a new emulsion.
This coating liquid contains heat-resistant fine particles and an organic binder in an amount as required, and these are dispersed in a medium such as water or an organic solvent (the organic binder may be dissolved in the medium). .
この塗工液は、耐熱性微粒子と必要に応じた量の有機バインダとを含み、これらが水や有機溶剤などの媒体に分散（有機バインダは媒体に溶解してもよい）されたものである。 When the heat-resistant porous layer contains an organic binder, the organic binder is dissolved or dispersed in the coating solution (slurry) medium (solvent) that forms the heat-resistant porous layer. It may be in the form of a new emulsion.
This coating liquid contains heat-resistant fine particles and an organic binder in an amount as required, and these are dispersed in a medium such as water or an organic solvent (the organic binder may be dissolved in the medium). .
塗工液の媒体として用いる有機溶剤としては、ポリオレフィン微多孔膜を溶解したり膨潤させたりするなどしてポリオレフィン微多孔膜にダメージを与えないものである。また、有機バインダを使用する場合にあっては、有機溶剤として有機バインダを均一に溶解可能なものである。有機溶剤は、このようなものであれば特に制限は無いが、例えば、テトラヒドロフラン（ＴＨＦ）などのフラン類；メチルエチルケトン（ＭＥＫ）、メチルイソブチルケトン（ＭＩＢＫ）などのケトン類；などが好適である。なお、高沸点の有機溶剤は、耐熱多孔質層形成用の塗工液をポリオレフィン微多孔膜に塗布した後、乾燥などによって有機溶剤を除去する際に、ポリオレフィン微多孔膜に熱溶融などのダメージを与える虞があるので好ましくない。
これらの有機溶剤を用いた場合、塗工液中に、多価アルコール（エチレングリコール、トリエチレングリコールなど）や界面活性剤（直鎖アルキルベンゼンスルホン酸塩、ポリオキシエチレンアルキルエーテル、ポリオキシエチルアルキルフェニルエーテルなど）などを適宜加えてもよい。 The organic solvent used as the coating liquid medium is one that does not damage the polyolefin microporous film by dissolving or swelling the polyolefin microporous film. When an organic binder is used, the organic binder can be uniformly dissolved as an organic solvent. The organic solvent is not particularly limited as long as it is such, and for example, furans such as tetrahydrofuran (THF); ketones such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK); In addition, high boiling point organic solvents may damage the polyolefin microporous membrane by heat melting or the like when the organic solvent is removed by drying after applying the coating liquid for heat-resistant porous layer formation to the polyolefin microporous membrane. This is not preferable because of the risk of giving
When these organic solvents are used, polyhydric alcohols (ethylene glycol, triethylene glycol, etc.) and surfactants (linear alkylbenzene sulfonate, polyoxyethylene alkyl ether, polyoxyethyl alkylphenyl) are used in the coating solution. Ether or the like) may be added as appropriate.
これらの有機溶剤を用いた場合、塗工液中に、多価アルコール（エチレングリコール、トリエチレングリコールなど）や界面活性剤（直鎖アルキルベンゼンスルホン酸塩、ポリオキシエチレンアルキルエーテル、ポリオキシエチルアルキルフェニルエーテルなど）などを適宜加えてもよい。 The organic solvent used as the coating liquid medium is one that does not damage the polyolefin microporous film by dissolving or swelling the polyolefin microporous film. When an organic binder is used, the organic binder can be uniformly dissolved as an organic solvent. The organic solvent is not particularly limited as long as it is such, and for example, furans such as tetrahydrofuran (THF); ketones such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK); In addition, high boiling point organic solvents may damage the polyolefin microporous membrane by heat melting or the like when the organic solvent is removed by drying after applying the coating liquid for heat-resistant porous layer formation to the polyolefin microporous membrane. This is not preferable because of the risk of giving
When these organic solvents are used, polyhydric alcohols (ethylene glycol, triethylene glycol, etc.) and surfactants (linear alkylbenzene sulfonate, polyoxyethylene alkyl ether, polyoxyethyl alkylphenyl) are used in the coating solution. Ether or the like) may be added as appropriate.
また、塗工液の媒体には、水を用いることもできる。その場合にも、塗工液中に、アルコール（エタノール、イソプロパノールなどの炭素数が６以下のアルコールなど）や界面活性剤（例えば、前記の有機溶剤を媒体とする塗工液に用い得るものとして例示したもの）を加えてもよい。
Also, water can be used as the medium of the coating liquid. Even in such a case, the coating liquid can be used in a coating liquid containing alcohol (such as ethanol or isopropanol having 6 or less carbon atoms) or a surfactant (for example, the above organic solvent as a medium). (Examples) may be added.
ポリオレフィン微多孔膜上に塗工液を塗布する方法としては、通常、慣用の流延または塗布方法が用いられる。具体的には、例えば、ロールコーター、エヤナイフコーター、ブレードコーター、ロッドコーター、バーコーター、コンマコーター、グラビアコーター、シルクスクリーンコーター、ダイコーター、マイクログラビアコーター法などの従来公知の塗工装置を用いる方法が挙げられる。
As a method for applying the coating liquid onto the polyolefin microporous film, a conventional casting or coating method is usually used. Specifically, for example, a conventionally known coating apparatus such as a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, a comma coater, a gravure coater, a silk screen coater, a die coater, or a micro gravure coater method is used. A method is mentioned.
次に、ポリオレフィン微多孔膜の片面または両面に塗布された塗工液を乾燥して塗工液中の媒体を除去することにより、耐熱多孔質層を形成する。
Next, the heat-resistant porous layer is formed by drying the coating liquid applied to one or both sides of the polyolefin microporous film and removing the medium in the coating liquid.
以下に、リチウムイオン二次電池やリチウムイオンキャパシタ等のなどの蓄電デバイスに用いられるセパレータについて説明する。セパレータの形状は、例えばリチウムイオン二次電池の形状等に応じて適宜調整するとよい。同様に、正極および負極の形状もリチウムイオン二次電池の形状に応じて適宜調整するとよい。
セパレータは、本実施形態の蓄電デバイス用セパレータフィルムで構成され、単層構造もしくは多層構造を有する。 Below, the separator used for electrical storage devices, such as a lithium ion secondary battery and a lithium ion capacitor, is demonstrated. The shape of the separator may be appropriately adjusted according to, for example, the shape of the lithium ion secondary battery. Similarly, the shapes of the positive electrode and the negative electrode may be appropriately adjusted according to the shape of the lithium ion secondary battery.
A separator is comprised with the separator film for electrical storage devices of this embodiment, and has a single layer structure or a multilayer structure.
セパレータは、本実施形態の蓄電デバイス用セパレータフィルムで構成され、単層構造もしくは多層構造を有する。 Below, the separator used for electrical storage devices, such as a lithium ion secondary battery and a lithium ion capacitor, is demonstrated. The shape of the separator may be appropriately adjusted according to, for example, the shape of the lithium ion secondary battery. Similarly, the shapes of the positive electrode and the negative electrode may be appropriately adjusted according to the shape of the lithium ion secondary battery.
A separator is comprised with the separator film for electrical storage devices of this embodiment, and has a single layer structure or a multilayer structure.
（非水電解液）
本実施形態の蓄電デバイスに用いられる非水電解液に使用される非水溶媒としては、環状カーボネート、鎖状エステルが好適に挙げられる。広い温度範囲、特に高温での電気化学特性が相乗的に向上するため、鎖状エステルが含まれることが好ましく、鎖状カーボネートが含まれることが更に好ましく、環状カーボネートと鎖状カーボネートの両方が含まれることがもっとも好ましい。なお、「鎖状エステル」なる用語は、鎖状カーボネート及び鎖状カルボン酸エステルを含む概念として用いる。 (Nonaqueous electrolyte)
As the nonaqueous solvent used in the nonaqueous electrolytic solution used in the electricity storage device of the present embodiment, a cyclic carbonate and a chain ester are preferably exemplified. In order to synergistically improve electrochemical properties in a wide temperature range, particularly at high temperatures, it is preferable that a chain ester is included, more preferably a chain carbonate is included, and both a cyclic carbonate and a chain carbonate are included. Most preferably. The term “chain ester” is used as a concept including a chain carbonate and a chain carboxylic acid ester.
本実施形態の蓄電デバイスに用いられる非水電解液に使用される非水溶媒としては、環状カーボネート、鎖状エステルが好適に挙げられる。広い温度範囲、特に高温での電気化学特性が相乗的に向上するため、鎖状エステルが含まれることが好ましく、鎖状カーボネートが含まれることが更に好ましく、環状カーボネートと鎖状カーボネートの両方が含まれることがもっとも好ましい。なお、「鎖状エステル」なる用語は、鎖状カーボネート及び鎖状カルボン酸エステルを含む概念として用いる。 (Nonaqueous electrolyte)
As the nonaqueous solvent used in the nonaqueous electrolytic solution used in the electricity storage device of the present embodiment, a cyclic carbonate and a chain ester are preferably exemplified. In order to synergistically improve electrochemical properties in a wide temperature range, particularly at high temperatures, it is preferable that a chain ester is included, more preferably a chain carbonate is included, and both a cyclic carbonate and a chain carbonate are included. Most preferably. The term “chain ester” is used as a concept including a chain carbonate and a chain carboxylic acid ester.
環状カーボネートとしては、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ビニレンカーボネート（ＶＣ）から選ばれる一種又は二種以上が挙げられ、ＥＣとＶＣの組み合わせ、ＰＣとＶＣの組み合わせが特に好ましい。
Examples of the cyclic carbonate include one or more selected from ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC), and a combination of EC and VC and a combination of PC and VC are particularly preferable.
また、非水溶媒がエチレンカーボネート及び／又はプロピレンカーボネートを含むと電極上に形成される被膜の安定性が増し、高温、高電圧でのサイクル特性が向上するので好ましい。エチレンカーボネート及び／又はプロピレンカーボネートの含有量は、非水溶媒の総体積に対し、好ましくは３体積％以上、より好ましくは５体積％以上、更に好ましくは７体積％以上である。また、その上限としては、好ましくは４５体積％以下、より好ましくは３５体積％以下、更に好ましくは２５体積％以下である。
In addition, it is preferable that the non-aqueous solvent contains ethylene carbonate and / or propylene carbonate because the stability of the film formed on the electrode is increased and the cycle characteristics at high temperature and high voltage are improved. The content of ethylene carbonate and / or propylene carbonate is preferably 3% by volume or more, more preferably 5% by volume or more, and still more preferably 7% by volume or more with respect to the total volume of the nonaqueous solvent. Moreover, as the upper limit, Preferably it is 45 volume% or less, More preferably, it is 35 volume% or less, More preferably, it is 25 volume% or less.
鎖状エステルとしては、非対称鎖状カーボネートとして、メチルエチルカーボネート（ＭＥＣ）、対称鎖状カーボネートとして、ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、鎖状カルボン酸エステルとして酢酸エチル（以下、ＥＡ）が好適に挙げられる。前記鎖状エステルの中でも、ＭＥＣとＥＡのような非対称かつエトキシ基を含有する鎖状エステルの組み合わせが可能である。
As the chain ester, methyl ethyl carbonate (MEC) as an asymmetric chain carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC) as a symmetric chain carbonate, ethyl acetate (hereinafter referred to as EA) as a chain carboxylate ester Are preferable. Among the chain esters, combinations of chain esters containing asymmetric and ethoxy groups such as MEC and EA are possible.
鎖状エステルの含有量は、特に制限されないが、非水溶媒の総体積に対して、６０～９０体積％の範囲で用いるのが好ましい。該含有量が６０体積％以上であれば非水電解液の粘度が高くなりすぎず、９０体積％以下であれば非水電解液の電気伝導度が低下して広い温度範囲、特に高温での電気化学特性が低下するおそれが少ないので上記範囲であることが好ましい。
The content of the chain ester is not particularly limited, but it is preferably used in the range of 60 to 90% by volume with respect to the total volume of the nonaqueous solvent. If the content is 60% by volume or more, the viscosity of the non-aqueous electrolyte does not become too high, and if it is 90% by volume or less, the electrical conductivity of the non-aqueous electrolyte is lowered and the temperature is wide, particularly at high temperatures. Since there is little possibility that an electrochemical characteristic will fall, it is preferable that it is the said range.
鎖状エステルの中でもＥＡが占める体積の割合は、非水溶媒中に１体積％以上が好ましく、２体積％以上がより好ましい。その上限としては、１０体積％以下がより好ましく、７体積％以下であると更に好ましい。非対称鎖状カーボネートはエチル基を有するとより好ましく、メチルエチルカーボネートが特に好ましい。
環状カーボネートと鎖状エステルの割合は、広い温度範囲、特に高温での電気化学特性向上の観点から、環状カーボネート：鎖状エステル(体積比)が１０：９０～４５：５５が好ましく、１５：８５～４０：６０がより好ましく、２０：８０～３５：６５が特に好ましい。 The proportion of the volume occupied by EA in the chain ester is preferably 1% by volume or more in the non-aqueous solvent, and more preferably 2% by volume or more. The upper limit is more preferably 10% by volume or less, and even more preferably 7% by volume or less. The asymmetric chain carbonate preferably has an ethyl group, and methyl ethyl carbonate is particularly preferable.
The ratio between the cyclic carbonate and the chain ester is preferably 10:90 to 45:55 in terms of the cyclic carbonate: chain ester (volume ratio) from the viewpoint of improving electrochemical characteristics over a wide temperature range, particularly at high temperatures, and 15:85. ˜40: 60 is more preferred, and 20:80 to 35:65 is particularly preferred.
環状カーボネートと鎖状エステルの割合は、広い温度範囲、特に高温での電気化学特性向上の観点から、環状カーボネート：鎖状エステル(体積比)が１０：９０～４５：５５が好ましく、１５：８５～４０：６０がより好ましく、２０：８０～３５：６５が特に好ましい。 The proportion of the volume occupied by EA in the chain ester is preferably 1% by volume or more in the non-aqueous solvent, and more preferably 2% by volume or more. The upper limit is more preferably 10% by volume or less, and even more preferably 7% by volume or less. The asymmetric chain carbonate preferably has an ethyl group, and methyl ethyl carbonate is particularly preferable.
The ratio between the cyclic carbonate and the chain ester is preferably 10:90 to 45:55 in terms of the cyclic carbonate: chain ester (volume ratio) from the viewpoint of improving electrochemical characteristics over a wide temperature range, particularly at high temperatures, and 15:85. ˜40: 60 is more preferred, and 20:80 to 35:65 is particularly preferred.
［電解質塩］
本実施形態の蓄電デバイスに用いられる電解質塩としては、リチウム塩が好適に挙げられる。
リチウム塩としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＮ（ＳＯ２Ｆ）２、ＬｉＮ（ＳＯ２ＣＦ３）２からなる群より選ばれる１種又は２種以上が好ましく、ＬｉＰＦ６、ＬｉＢＦ４及びＬｉＮ（ＳＯ２Ｆ）２から選ばれる１種又は２種以上が更に好ましく、ＬｉＰＦ６を用いることが最も好ましい。 [Electrolyte salt]
As the electrolyte salt used in the electricity storage device of this embodiment, a lithium salt is preferably exemplified.
The lithium salt is preferably one or more selected from the group consisting of LiPF 6 , LiBF 4 , LiN (SO 2 F) 2 , LiN (SO 2 CF 3 ) 2 , and LiPF 6 , LiBF 4 and LiN ( One or more selected from SO 2 F) 2 is more preferred, and LiPF 6 is most preferred.
本実施形態の蓄電デバイスに用いられる電解質塩としては、リチウム塩が好適に挙げられる。
リチウム塩としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＮ（ＳＯ２Ｆ）２、ＬｉＮ（ＳＯ２ＣＦ３）２からなる群より選ばれる１種又は２種以上が好ましく、ＬｉＰＦ６、ＬｉＢＦ４及びＬｉＮ（ＳＯ２Ｆ）２から選ばれる１種又は２種以上が更に好ましく、ＬｉＰＦ６を用いることが最も好ましい。 [Electrolyte salt]
As the electrolyte salt used in the electricity storage device of this embodiment, a lithium salt is preferably exemplified.
The lithium salt is preferably one or more selected from the group consisting of LiPF 6 , LiBF 4 , LiN (SO 2 F) 2 , LiN (SO 2 CF 3 ) 2 , and LiPF 6 , LiBF 4 and LiN ( One or more selected from SO 2 F) 2 is more preferred, and LiPF 6 is most preferred.
［非水電解液の製造］
本実施形態の蓄電デバイスに用いられる非水電解液は、例えば、前記の非水溶媒を混合し、これに前記の電解質塩及び該非水電解液に対して溶解助剤などを特定の混合比率で混合させた組成物を添加する方法により得ることができる。この際、用いる非水溶媒及び非水電解液に加える化合物は、生産性を著しく低下させない範囲内で、予め精製して、不純物が極力少ないものを用いることが好ましい。 [Production of non-aqueous electrolyte]
The non-aqueous electrolyte used in the electricity storage device of the present embodiment is, for example, mixed with the non-aqueous solvent, and this is mixed with the electrolyte salt and the non-aqueous electrolyte at a specific mixing ratio. It can be obtained by a method of adding a mixed composition. At this time, it is preferable that the compound added to the non-aqueous solvent and the non-aqueous electrolyte to be used is one that is purified in advance and has as few impurities as possible within a range that does not significantly reduce the productivity.
本実施形態の蓄電デバイスに用いられる非水電解液は、例えば、前記の非水溶媒を混合し、これに前記の電解質塩及び該非水電解液に対して溶解助剤などを特定の混合比率で混合させた組成物を添加する方法により得ることができる。この際、用いる非水溶媒及び非水電解液に加える化合物は、生産性を著しく低下させない範囲内で、予め精製して、不純物が極力少ないものを用いることが好ましい。 [Production of non-aqueous electrolyte]
The non-aqueous electrolyte used in the electricity storage device of the present embodiment is, for example, mixed with the non-aqueous solvent, and this is mixed with the electrolyte salt and the non-aqueous electrolyte at a specific mixing ratio. It can be obtained by a method of adding a mixed composition. At this time, it is preferable that the compound added to the non-aqueous solvent and the non-aqueous electrolyte to be used is one that is purified in advance and has as few impurities as possible within a range that does not significantly reduce the productivity.
本発明のポリオレフィン微多孔膜は、下記の第１、第２の蓄電デバイスに使用することができ、非水電解質として液体状のものだけでなくゲル化されているものも使用できる。
中でも電解質塩にリチウム塩を使用するリチウムイオン電池（第１の蓄電デバイス）用やリチウムイオンキャパシタ（第２の蓄電デバイス）用のセパレータとして用いることが好ましく、リチウムイオン電池用に用いることがより好ましく、リチウムイオン二次電池用に用いることが更に好ましい。 The polyolefin microporous membrane of the present invention can be used in the following first and second electricity storage devices, and not only a liquid but also a gelled nonaqueous electrolyte can be used.
Among them, it is preferably used as a separator for a lithium ion battery (first power storage device) or a lithium ion capacitor (second power storage device) using a lithium salt as an electrolyte salt, and more preferably used for a lithium ion battery. More preferably, it is used for a lithium ion secondary battery.
中でも電解質塩にリチウム塩を使用するリチウムイオン電池（第１の蓄電デバイス）用やリチウムイオンキャパシタ（第２の蓄電デバイス）用のセパレータとして用いることが好ましく、リチウムイオン電池用に用いることがより好ましく、リチウムイオン二次電池用に用いることが更に好ましい。 The polyolefin microporous membrane of the present invention can be used in the following first and second electricity storage devices, and not only a liquid but also a gelled nonaqueous electrolyte can be used.
Among them, it is preferably used as a separator for a lithium ion battery (first power storage device) or a lithium ion capacitor (second power storage device) using a lithium salt as an electrolyte salt, and more preferably used for a lithium ion battery. More preferably, it is used for a lithium ion secondary battery.
（蓄電デバイス）
本発明の蓄電デバイスは、正極と、負極と、前記正極と前記負極との間に介在するセパレータとしての本発明のポリオレフィン微多孔膜を有する蓄電デバイス用セパレータフィルムと、少なくともセパレータに含浸される非水電解液と、を備える。 (Electric storage device)
An electricity storage device of the present invention comprises a positive electrode, a negative electrode, a separator film for an electricity storage device having the polyolefin microporous film of the present invention as a separator interposed between the positive electrode and the negative electrode, and at least the separator is impregnated. A water electrolyte solution.
本発明の蓄電デバイスは、正極と、負極と、前記正極と前記負極との間に介在するセパレータとしての本発明のポリオレフィン微多孔膜を有する蓄電デバイス用セパレータフィルムと、少なくともセパレータに含浸される非水電解液と、を備える。 (Electric storage device)
An electricity storage device of the present invention comprises a positive electrode, a negative electrode, a separator film for an electricity storage device having the polyolefin microporous film of the present invention as a separator interposed between the positive electrode and the negative electrode, and at least the separator is impregnated. A water electrolyte solution.
［リチウムイオン二次電池］
本発明の蓄電デバイスとしてリチウムイオン二次電池は、正極、負極及び非水溶媒に電解質塩が溶解されている前記非水電解液を有する。非水電解液以外の正極、負極等の構成部材は特に制限なく使用できる。 [Lithium ion secondary battery]
A lithium ion secondary battery as the electricity storage device of the present invention has the nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a positive electrode, a negative electrode, and a nonaqueous solvent. Components other than the non-aqueous electrolyte, such as a positive electrode and a negative electrode, can be used without particular limitation.
本発明の蓄電デバイスとしてリチウムイオン二次電池は、正極、負極及び非水溶媒に電解質塩が溶解されている前記非水電解液を有する。非水電解液以外の正極、負極等の構成部材は特に制限なく使用できる。 [Lithium ion secondary battery]
A lithium ion secondary battery as the electricity storage device of the present invention has the nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a positive electrode, a negative electrode, and a nonaqueous solvent. Components other than the non-aqueous electrolyte, such as a positive electrode and a negative electrode, can be used without particular limitation.
例えば、リチウムイオン二次電池用正極活物質としては、コバルト、マンガン、及びニッケルからなる群より選ばれる１種又は２種以上を含有するリチウムとの複合金属酸化物が使用される。これらの正極活物質は、１種単独で用いるか又は２種以上を組み合わせて用いることができる。
For example, as the positive electrode active material for a lithium ion secondary battery, a composite metal oxide with lithium containing one or more selected from the group consisting of cobalt, manganese, and nickel is used. These positive electrode active materials can be used alone or in combination of two or more.
このようなリチウム複合金属酸化物としては、例えば、ＬｉＣｏＯ２、ＬｉＣｏ１－ｘＭｘＯ２（但し、ＭはＳｎ、Ｍｇ、Ｆｅ、Ｔｉ、Ａｌ、Ｚｒ、Ｃｒ、Ｖ、Ｇａ、Ｚｎ、及びＣｕから選ばれる１種又は２種以上の元素）、ＬｉＭｎ２Ｏ４、ＬｉＮｉＯ２、ＬｉＣｏ１－ｘＮｉｘＯ２、ＬｉＣｏ１／３Ｎｉ１／３Ｍｎ１／３Ｏ２、ＬｉＮｉ０．５Ｍｎ０．３Ｃｏ０．２Ｍｎ０．３Ｏ２、ＬｉＮｉ０．８Ｍｎ０．１Ｃｏ０．１Ｏ２、ＬｉＮｉ０．８Ｃｏ０．１５Ａｌ０．０５Ｏ２、Ｌｉ２ＭｎＯ３とＬｉＭＯ２（Ｍは、Ｃｏ、Ｎｉ、Ｍｎ、Ｆｅ等の遷移金属）との固溶体、及びＬｉＮｉ１／２Ｍｎ３／２Ｏ４から選ばれる１種以上が好適に挙げられる。
Examples of such a lithium composite metal oxide include LiCoO 2 , LiCo 1-x M x O 2 (where M is Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, and 1 or 2 or more elements selected from Cu), LiMn 2 O 4 , LiNiO 2 , LiCo 1-x NixO 2 , LiCo 1/3 Ni 1/3 Mn 1/3 O 2 , LiNi 0.5 Mn 0 .3 Co 0.2 Mn 0.3 O 2 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , Li 2 MnO 3 and LiMO 2 Preferable examples include one or more selected from a solid solution with M (transition metals such as Co, Ni, Mn, and Fe) and LiNi 1/2 Mn 3/2 O 4 .
正極の導電剤は、化学変化を起こさない電子伝導材料であれば特に制限はない。例えば、天然黒鉛（鱗片状黒鉛等）、人造黒鉛等のグラファイト、アセチレンブラックなどから選ばれる１種又は２種以上のカーボンブラック等が挙げられる。
The positive electrode conductive agent is not particularly limited as long as it is an electron conductive material that does not cause a chemical change. Examples thereof include one or more carbon blacks selected from natural graphite (eg, flake graphite), graphite such as artificial graphite, acetylene black, and the like.
正極は、正極合剤を集電体のアルミニウム箔やステンレス製板等に塗布して、乾燥、加圧成型した後、所定条件のもとに加熱処理することにより作製できる。
正極合剤は、前記の正極活物質をアセチレンブラック、カーボンブラック等の導電剤、及びポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、スチレンとブタジエンの共重合体（ＳＢＲ）、アクリロニトリルとブタジエンの共重合体（ＮＢＲ）、カルボキシメチルセルロース（ＣＭＣ）等の結着剤と混合し、これに溶剤を加えて混練して得られる。 The positive electrode can be produced by applying the positive electrode mixture to an aluminum foil or a stainless steel plate as a current collector, drying and press-molding, and then heat-treating under predetermined conditions.
The positive electrode mixture is a mixture of the positive electrode active material with a conductive agent such as acetylene black and carbon black, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of styrene and butadiene (SBR), and acrylonitrile. It is obtained by mixing with a binder such as a butadiene copolymer (NBR) or carboxymethylcellulose (CMC), adding a solvent thereto, and kneading.
正極合剤は、前記の正極活物質をアセチレンブラック、カーボンブラック等の導電剤、及びポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、スチレンとブタジエンの共重合体（ＳＢＲ）、アクリロニトリルとブタジエンの共重合体（ＮＢＲ）、カルボキシメチルセルロース（ＣＭＣ）等の結着剤と混合し、これに溶剤を加えて混練して得られる。 The positive electrode can be produced by applying the positive electrode mixture to an aluminum foil or a stainless steel plate as a current collector, drying and press-molding, and then heat-treating under predetermined conditions.
The positive electrode mixture is a mixture of the positive electrode active material with a conductive agent such as acetylene black and carbon black, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of styrene and butadiene (SBR), and acrylonitrile. It is obtained by mixing with a binder such as a butadiene copolymer (NBR) or carboxymethylcellulose (CMC), adding a solvent thereto, and kneading.
リチウムイオン二次電池用負極活物質としては、リチウム金属やリチウム合金、及びリチウムを吸蔵及び放出することが可能な炭素材料、スズ（単体）、スズ化合物、ケイ素（単体）、ケイ素化合物、又はＬｉ４Ｔｉ５Ｏ１２等のチタン酸リチウム化合物等を一種単独で又は二種以上を組み合わせて用いることができる。
Examples of the negative electrode active material for a lithium ion secondary battery include lithium metal and lithium alloy, and a carbon material capable of inserting and extracting lithium, tin (single), tin compound, silicon (single), silicon compound, or Li A lithium titanate compound such as 4Ti 5 O 12 can be used alone or in combination of two or more.
これらの中では、リチウムイオンの吸蔵及び放出能力において、人造黒鉛や天然黒鉛等の高結晶性の炭素材料を使用することがより好ましい。
Among these, it is more preferable to use a highly crystalline carbon material such as artificial graphite or natural graphite in terms of the ability to occlude and release lithium ions.
特に複数の扁平状の黒鉛質微粒子が互いに非平行に集合又は結合した塊状構造を有する人造黒鉛粒子や、圧縮力、摩擦力、剪断力等の機械的作用を繰り返し与え、鱗片状天然黒鉛を球形化処理した粒子、を用いることが好ましい。
In particular, artificial graphite particles having a massive structure in which a plurality of flat graphite fine particles are assembled or bonded non-parallel to each other, and mechanical actions such as compressive force, frictional force, shearing force, etc. are repeatedly applied, and scaly natural graphite is spherical. It is preferable to use particles that have been treated.
負極は、負極活物質と、上記の正極の作製と同様な導電剤、結着剤とを、高沸点溶剤を用いて混練して負極合剤とした後、この負極合剤を集電体の銅箔等に塗布して、乾燥、加圧成型した後、所定条件のもとに加熱処理することにより作製することができる。
The negative electrode is prepared by kneading a negative electrode active material and the same conductive agent and binder as those for the above positive electrode using a high-boiling solvent to form a negative electrode mixture. It can be produced by applying it to a copper foil and the like, drying and press molding, and then heat-treating it under predetermined conditions.
［リチウムイオン二次電池］
本発明の蓄電デバイスの１つとして、リチウムイオン二次電池の構造に特に限定はなく、コイン型電池、円筒型電池、角型電池、又はラミネート電池等を適用できる。 [Lithium ion secondary battery]
As one of the electricity storage devices of the present invention, the structure of the lithium ion secondary battery is not particularly limited, and a coin-type battery, a cylindrical battery, a square battery, a laminated battery, or the like can be applied.
本発明の蓄電デバイスの１つとして、リチウムイオン二次電池の構造に特に限定はなく、コイン型電池、円筒型電池、角型電池、又はラミネート電池等を適用できる。 [Lithium ion secondary battery]
As one of the electricity storage devices of the present invention, the structure of the lithium ion secondary battery is not particularly limited, and a coin-type battery, a cylindrical battery, a square battery, a laminated battery, or the like can be applied.
巻回型のリチウムイオン二次電池は、例えば、電極体が非水電解液と共に電池ケースに収容された構成を有する。電極体は、正極と負極とセパレータとによって構成されている。非水電解液の少なくとも一部は、電極体に含浸されている。
The wound lithium ion secondary battery has, for example, a configuration in which an electrode body is housed in a battery case together with a non-aqueous electrolyte. The electrode body includes a positive electrode, a negative electrode, and a separator. At least a part of the non-aqueous electrolyte is impregnated in the electrode body.
巻回型のリチウムイオン二次電池では、正極として、長尺シート状の正極集電体と、正極活物質を含み且つ正極集電体上に設けられた正極合材層とを含む。負極として、長尺シート状の負極集電体と、負極活物質を含み且つ負極集電体上に設けられた負極合材層とを含む。
セパレータは、正極および負極と同様に、長尺シート状に形成されている。正極および負極は、それらの間にセパレータを介在させ筒状に巻回される。 In a wound lithium ion secondary battery, as a positive electrode, a long sheet-shaped positive electrode current collector and a positive electrode mixture layer including a positive electrode active material and provided on the positive electrode current collector are included. As a negative electrode, a long sheet-like negative electrode current collector and a negative electrode mixture layer including a negative electrode active material and provided on the negative electrode current collector are included.
The separator is formed in a long sheet shape like the positive electrode and the negative electrode. The positive electrode and the negative electrode are wound in a cylindrical shape with a separator interposed therebetween.
セパレータは、正極および負極と同様に、長尺シート状に形成されている。正極および負極は、それらの間にセパレータを介在させ筒状に巻回される。 In a wound lithium ion secondary battery, as a positive electrode, a long sheet-shaped positive electrode current collector and a positive electrode mixture layer including a positive electrode active material and provided on the positive electrode current collector are included. As a negative electrode, a long sheet-like negative electrode current collector and a negative electrode mixture layer including a negative electrode active material and provided on the negative electrode current collector are included.
The separator is formed in a long sheet shape like the positive electrode and the negative electrode. The positive electrode and the negative electrode are wound in a cylindrical shape with a separator interposed therebetween.
電池ケースは、有底円筒状のケース本体と、ケース本体の開口部を塞ぐ蓋とを備える。
蓋およびケース本体は例えば金属製であり互いに絶縁されている。蓋は正極集電体に電気的に接続され、ケース本体は負極集電体に電気的に接続されている。なお、蓋が正極端子、ケース本体が負極端子をそれぞれ兼ねるようにしてもよい。 The battery case includes a bottomed cylindrical case body and a lid that closes an opening of the case body.
The lid and the case main body are made of, for example, metal and are insulated from each other. The lid is electrically connected to the positive electrode current collector, and the case body is electrically connected to the negative electrode current collector. In addition, you may make it a lid | cover serve as a positive electrode terminal, and a case main body may each serve as a negative electrode terminal.
蓋およびケース本体は例えば金属製であり互いに絶縁されている。蓋は正極集電体に電気的に接続され、ケース本体は負極集電体に電気的に接続されている。なお、蓋が正極端子、ケース本体が負極端子をそれぞれ兼ねるようにしてもよい。 The battery case includes a bottomed cylindrical case body and a lid that closes an opening of the case body.
The lid and the case main body are made of, for example, metal and are insulated from each other. The lid is electrically connected to the positive electrode current collector, and the case body is electrically connected to the negative electrode current collector. In addition, you may make it a lid | cover serve as a positive electrode terminal, and a case main body may each serve as a negative electrode terminal.
リチウムイオン二次電池は、－４０～１００℃、好ましくは－１０～８０℃で充放電することができる。また、巻回型リチウムイオン二次電池の内圧上昇の対策として、電池の蓋に安全弁を設ける、電池のケース本体やガスケット等の部材に切り込みを入れる方法も採用することができる。また、過充電防止の安全対策として、電池の内圧を感知して電流を遮断する電流遮断機構を蓋に設けることもできる。
The lithium ion secondary battery can be charged and discharged at −40 to 100 ° C., preferably −10 to 80 ° C. In addition, as a countermeasure against an increase in the internal pressure of the wound lithium ion secondary battery, a method in which a safety valve is provided on the battery lid and a member such as a battery case body or a gasket is cut can be employed. Further, as a safety measure for preventing overcharge, a current interruption mechanism that senses the internal pressure of the battery and interrupts the current can be provided on the lid.
［巻回型リチウムイオン二次電池の製造］
一例として、リチウムイオン二次電池の製造手順について以下に説明する。
まず、正極、負極、およびセパレータをそれぞれ作製する。次に、それらを重ね合わせて円筒状に巻回することにより、電極体を組み立てる。次いで電極体をケース本体に挿入し、ケース本体内に非水電解液を注入する。これにより、電極体に非水電解液が含浸する。ケース本体内に非水電解液を注入した後、ケース本体に蓋を被せ、蓋およびケース本体を密封する。なお、巻回後の電極体の形状は円筒状に限られない。例えば、正極とセパレータと負極とを巻回した後、側方から圧力を加えることにより、偏平形状に形成してもよい。 [Manufacture of wound-type lithium ion secondary batteries]
As an example, a manufacturing procedure of a lithium ion secondary battery will be described below.
First, a positive electrode, a negative electrode, and a separator are prepared. Next, the electrode body is assembled by overlapping them and winding them into a cylindrical shape. Next, the electrode body is inserted into the case body, and a non-aqueous electrolyte is injected into the case body. Thereby, the non-aqueous electrolyte is impregnated in the electrode body. After injecting the non-aqueous electrolyte into the case body, the case body is covered with a lid, and the lid and the case body are sealed. In addition, the shape of the electrode body after winding is not restricted to a cylindrical shape. For example, after winding the positive electrode, the separator, and the negative electrode, a flat shape may be formed by applying pressure from the side.
一例として、リチウムイオン二次電池の製造手順について以下に説明する。
まず、正極、負極、およびセパレータをそれぞれ作製する。次に、それらを重ね合わせて円筒状に巻回することにより、電極体を組み立てる。次いで電極体をケース本体に挿入し、ケース本体内に非水電解液を注入する。これにより、電極体に非水電解液が含浸する。ケース本体内に非水電解液を注入した後、ケース本体に蓋を被せ、蓋およびケース本体を密封する。なお、巻回後の電極体の形状は円筒状に限られない。例えば、正極とセパレータと負極とを巻回した後、側方から圧力を加えることにより、偏平形状に形成してもよい。 [Manufacture of wound-type lithium ion secondary batteries]
As an example, a manufacturing procedure of a lithium ion secondary battery will be described below.
First, a positive electrode, a negative electrode, and a separator are prepared. Next, the electrode body is assembled by overlapping them and winding them into a cylindrical shape. Next, the electrode body is inserted into the case body, and a non-aqueous electrolyte is injected into the case body. Thereby, the non-aqueous electrolyte is impregnated in the electrode body. After injecting the non-aqueous electrolyte into the case body, the case body is covered with a lid, and the lid and the case body are sealed. In addition, the shape of the electrode body after winding is not restricted to a cylindrical shape. For example, after winding the positive electrode, the separator, and the negative electrode, a flat shape may be formed by applying pressure from the side.
上記のリチウムイオン二次電池は、各種用途向けの二次電池として利用可能である。例えば、自動車等の車両に搭載され、車両を駆動するモータ等の駆動源用の電源として好適に利用することができる。車両の種類は特に限定されないが、例えば、ハイブリッド自動車、プラグインハイブリッド自動車、電気自動車、燃料電池自動車等があげられる。かかるリチウムイオン二次電池は、単独で使用されてもよく、直列および／または並列に複数の電池を接続して使用してもよい。
The above lithium ion secondary battery can be used as a secondary battery for various applications. For example, it can be suitably used as a power source for a drive source such as a motor that is mounted on a vehicle such as an automobile and drives the vehicle. Although the kind of vehicle is not specifically limited, For example, a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle, a fuel cell vehicle etc. are mention | raise | lifted. Such a lithium ion secondary battery may be used alone, or may be used by connecting a plurality of batteries in series and / or in parallel.
［リチウムイオンキャパシタ］
本発明の他の蓄電デバイスとしてリチウムイオンキャパシタがあげられる。本実施形態のリチウムイオンキャパシタは、セパレータとしての本発明のポリオレフィン微多孔膜を有する蓄電デバイス用セパレータフィルム、非水電解液、正極、負極を有する。リチウムイオンキャパシタは、負極であるグラファイト等の炭素材料へのリチウムイオンのインターカレーションを利用してエネルギーを貯蔵することができる。正極は、例えば活性炭電極と電解液との間の電気二重層を利用したものや、π共役高分子電極のドープ／脱ドープ反応を利用したもの等が挙げられる。電解液には少なくともＬｉＰＦ６等のリチウム塩が含まれる。 [Lithium ion capacitor]
Another example of the electricity storage device of the present invention is a lithium ion capacitor. The lithium ion capacitor of this embodiment has the separator film for electrical storage devices which has the polyolefin microporous film of this invention as a separator, a nonaqueous electrolyte, a positive electrode, and a negative electrode. A lithium ion capacitor can store energy by utilizing intercalation of lithium ions into a carbon material such as graphite as a negative electrode. Examples of the positive electrode include those using an electric double layer between an activated carbon electrode and an electrolytic solution, and those using a π-conjugated polymer electrode doping / dedoping reaction. The electrolytic solution contains at least a lithium salt such as LiPF 6 .
本発明の他の蓄電デバイスとしてリチウムイオンキャパシタがあげられる。本実施形態のリチウムイオンキャパシタは、セパレータとしての本発明のポリオレフィン微多孔膜を有する蓄電デバイス用セパレータフィルム、非水電解液、正極、負極を有する。リチウムイオンキャパシタは、負極であるグラファイト等の炭素材料へのリチウムイオンのインターカレーションを利用してエネルギーを貯蔵することができる。正極は、例えば活性炭電極と電解液との間の電気二重層を利用したものや、π共役高分子電極のドープ／脱ドープ反応を利用したもの等が挙げられる。電解液には少なくともＬｉＰＦ６等のリチウム塩が含まれる。 [Lithium ion capacitor]
Another example of the electricity storage device of the present invention is a lithium ion capacitor. The lithium ion capacitor of this embodiment has the separator film for electrical storage devices which has the polyolefin microporous film of this invention as a separator, a nonaqueous electrolyte, a positive electrode, and a negative electrode. A lithium ion capacitor can store energy by utilizing intercalation of lithium ions into a carbon material such as graphite as a negative electrode. Examples of the positive electrode include those using an electric double layer between an activated carbon electrode and an electrolytic solution, and those using a π-conjugated polymer electrode doping / dedoping reaction. The electrolytic solution contains at least a lithium salt such as LiPF 6 .
なお、上記では巻回型リチウムイオン二次電池について記載したが、本発明はこれに限らず、ラミネート型リチウムイオン二次電池に適用してもよい。
例えば、正極または負極の電極を一対のセパレータによってサンドイッチして包装する。本実施形態にあっては、正極を袋詰電極にしている。セパレータは、電極よりもやや大きいサイズを有している。電極の本体を一対のセパレータで挟み込みつつ、電極端部から出っ張ったタブをセパレータから外部に突出させる。重ねられた一対のセパレータの側縁同士を接合して袋詰めにし、このセパレータで袋詰めされた一方の電極と他方の電極とを交互に積層し電解液を含浸させることでラミネート型電池を作製することができる。このとき、厚みを薄型化するために、これらセパレータおよび電極を厚み方向に圧縮してもよい。 In addition, although the wound type lithium ion secondary battery was described above, the present invention is not limited thereto, and may be applied to a laminate type lithium ion secondary battery.
For example, the positive electrode or the negative electrode is sandwiched and packaged by a pair of separators. In this embodiment, the positive electrode is a packaged electrode. The separator has a size slightly larger than the electrode. While sandwiching the main body of the electrode between the pair of separators, the tab protruding from the end of the electrode is projected outward from the separator. Bonding the side edges of a pair of stacked separators to form a bag, and alternately laminating one electrode and the other electrode packed in this separator and impregnating the electrolyte solution to produce a laminated battery can do. At this time, in order to reduce the thickness, the separator and the electrode may be compressed in the thickness direction.
例えば、正極または負極の電極を一対のセパレータによってサンドイッチして包装する。本実施形態にあっては、正極を袋詰電極にしている。セパレータは、電極よりもやや大きいサイズを有している。電極の本体を一対のセパレータで挟み込みつつ、電極端部から出っ張ったタブをセパレータから外部に突出させる。重ねられた一対のセパレータの側縁同士を接合して袋詰めにし、このセパレータで袋詰めされた一方の電極と他方の電極とを交互に積層し電解液を含浸させることでラミネート型電池を作製することができる。このとき、厚みを薄型化するために、これらセパレータおよび電極を厚み方向に圧縮してもよい。 In addition, although the wound type lithium ion secondary battery was described above, the present invention is not limited thereto, and may be applied to a laminate type lithium ion secondary battery.
For example, the positive electrode or the negative electrode is sandwiched and packaged by a pair of separators. In this embodiment, the positive electrode is a packaged electrode. The separator has a size slightly larger than the electrode. While sandwiching the main body of the electrode between the pair of separators, the tab protruding from the end of the electrode is projected outward from the separator. Bonding the side edges of a pair of stacked separators to form a bag, and alternately laminating one electrode and the other electrode packed in this separator and impregnating the electrolyte solution to produce a laminated battery can do. At this time, in order to reduce the thickness, the separator and the electrode may be compressed in the thickness direction.
次に実施例を示し、本発明を更に詳細に説明するが、本発明はこれら一実施例に限定されるものではない。
Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
（評価実験方法）
以下に示す方法により製造したポリオレフィン微多孔膜および蓄電デバイス用セパレータフィルム、これらの原料および原反について、以下に示す項目を以下に示す方法により評価した。 (Evaluation experiment method)
The following items were evaluated for the polyolefin microporous membrane and the electricity storage device separator film produced by the method described below, as well as their raw materials and raw materials, by the following method.
以下に示す方法により製造したポリオレフィン微多孔膜および蓄電デバイス用セパレータフィルム、これらの原料および原反について、以下に示す項目を以下に示す方法により評価した。 (Evaluation experiment method)
The following items were evaluated for the polyolefin microporous membrane and the electricity storage device separator film produced by the method described below, as well as their raw materials and raw materials, by the following method.
［剥離強度測定］
ラミネート工程後に得られた積層フィルムから幅方向（ＴＤ）：１５ｍｍ×長さ方向（ＭＤ）：２００ｍｍの試験片を、積層フィルムのＴＤ方向中心部とＴＤ方向両端部（端部より１０ｍｍ内側の位置を試験片のＴＤ方向端面とする）とからそれぞれ採取した。各試験片について、それぞれＡ面（一方の面）から接着面の一部を剥がしたサンプルとＢ面（他方の面）から接着面の一部を剥がしたサンプルとを作成し、各積層フィルム毎に合計６点のサンプルを作成した。各サンプルを、ＯＲＩＥＮＴＥＣ社製の引張試験機ＲＴＣ－１２１０ＡにＴ状態にセットして、１００Ｎのロードセルを用い、チャック間距離５０ｍｍ、クロスヘッドスピード５０ｍｍ／ｍｉｎ．の条件にて、ＭＤ方向の層間剥離強度を測定した。剥離開始後、１２０ｍｍ、１４０ｍｍ、１６０ｍｍ、１８０ｍｍ、２００ｍｍ剥離時の剥離強度を測定し、その平均値を剥離強度として評価した。なお、表１中に記載された単位「ｇ／１５ｍｍ」は幅方向（ＴＤ方向）に１５ｍｍで切り出されたサンプルの剥離強度であることを意味している。 [Peel strength measurement]
A test piece of width direction (TD): 15 mm × length direction (MD): 200 mm is obtained from the laminated film obtained after the laminating step, and a TD direction center part and TD direction both end parts (positions 10 mm inside from the end part). Is taken as the end face in the TD direction of the test piece). For each test piece, a sample in which a part of the adhesive surface was peeled off from the A surface (one surface) and a sample in which a part of the adhesive surface was peeled off from the B surface (the other surface) were prepared. A total of 6 samples were prepared. Each sample was set in a T state on a tensile tester RTC-1210A manufactured by ORIENTEC, using a 100N load cell, a distance between chucks of 50 mm, and a crosshead speed of 50 mm / min. Under the conditions, the delamination strength in the MD direction was measured. After the start of peeling, the peeling strength at 120 mm, 140 mm, 160 mm, 180 mm, and 200 mm peeling was measured, and the average value was evaluated as the peeling strength. The unit “g / 15 mm” described in Table 1 means the peel strength of a sample cut out by 15 mm in the width direction (TD direction).
ラミネート工程後に得られた積層フィルムから幅方向（ＴＤ）：１５ｍｍ×長さ方向（ＭＤ）：２００ｍｍの試験片を、積層フィルムのＴＤ方向中心部とＴＤ方向両端部（端部より１０ｍｍ内側の位置を試験片のＴＤ方向端面とする）とからそれぞれ採取した。各試験片について、それぞれＡ面（一方の面）から接着面の一部を剥がしたサンプルとＢ面（他方の面）から接着面の一部を剥がしたサンプルとを作成し、各積層フィルム毎に合計６点のサンプルを作成した。各サンプルを、ＯＲＩＥＮＴＥＣ社製の引張試験機ＲＴＣ－１２１０ＡにＴ状態にセットして、１００Ｎのロードセルを用い、チャック間距離５０ｍｍ、クロスヘッドスピード５０ｍｍ／ｍｉｎ．の条件にて、ＭＤ方向の層間剥離強度を測定した。剥離開始後、１２０ｍｍ、１４０ｍｍ、１６０ｍｍ、１８０ｍｍ、２００ｍｍ剥離時の剥離強度を測定し、その平均値を剥離強度として評価した。なお、表１中に記載された単位「ｇ／１５ｍｍ」は幅方向（ＴＤ方向）に１５ｍｍで切り出されたサンプルの剥離強度であることを意味している。 [Peel strength measurement]
A test piece of width direction (TD): 15 mm × length direction (MD): 200 mm is obtained from the laminated film obtained after the laminating step, and a TD direction center part and TD direction both end parts (
［膜厚測定］
試料よりＭＤ５０ｍｍ、全幅にわたるテープ状の試験片を５枚用意する。５枚の試験片を重ね、測定点が２５点になるように幅方向に等間隔に、ファインプリューフ社製電気マイクロメーター（ミリトロン１２４０触針５ｍｍφ（フラット面、針圧０．７５Ｎ））を用い厚さを測定した。測定値の１／５の値を各点の一枚あたりの厚さとし、その平均値を算出し、膜厚とした。 [Film thickness measurement]
Five tape-shaped test pieces are prepared from the sample with an MD of 50 mm and a full width. Five test pieces are stacked, and an electric micrometer (Millitron 1240 stylus 5 mmφ (flat surface, stylus pressure 0.75 N)) manufactured by Finepreuf Co., Ltd. is equally spaced in the width direction so that the measurement points are 25 points. The thickness used was measured. The value of 1/5 of the measured value was taken as the thickness of each point, and the average value was calculated as the film thickness.
試料よりＭＤ５０ｍｍ、全幅にわたるテープ状の試験片を５枚用意する。５枚の試験片を重ね、測定点が２５点になるように幅方向に等間隔に、ファインプリューフ社製電気マイクロメーター（ミリトロン１２４０触針５ｍｍφ（フラット面、針圧０．７５Ｎ））を用い厚さを測定した。測定値の１／５の値を各点の一枚あたりの厚さとし、その平均値を算出し、膜厚とした。 [Film thickness measurement]
Five tape-shaped test pieces are prepared from the sample with an MD of 50 mm and a full width. Five test pieces are stacked, and an electric micrometer (Millitron 1240 stylus 5 mmφ (flat surface, stylus pressure 0.75 N)) manufactured by Finepreuf Co., Ltd. is equally spaced in the width direction so that the measurement points are 25 points. The thickness used was measured. The value of 1/5 of the measured value was taken as the thickness of each point, and the average value was calculated as the film thickness.
［厚みの変動係数（Ｃ．Ｖ．）］
原反の厚みの変動係数（Ｃ．Ｖ．）は、上記の膜厚測定と同様にして、測定点が２５点になるように幅方向に等間隔に試験片の厚みを測定し、その結果の標準偏差 [Thickness variation coefficient (CV)]
The coefficient of variation (C.V.) of the thickness of the original fabric is the same as in the film thickness measurement described above, and the thicknesses of the test pieces are measured at equal intervals in the width direction so that the measurement points are 25 points. Standard deviation of
原反の厚みの変動係数（Ｃ．Ｖ．）は、上記の膜厚測定と同様にして、測定点が２５点になるように幅方向に等間隔に試験片の厚みを測定し、その結果の標準偏差 [Thickness variation coefficient (CV)]
The coefficient of variation (C.V.) of the thickness of the original fabric is the same as in the film thickness measurement described above, and the thicknesses of the test pieces are measured at equal intervals in the width direction so that the measurement points are 25 points. Standard deviation of
［複屈折］
偏光顕微鏡を使用し、直交ニコル下でベレックコンペンセータを用いて測定された値である。 [Birefringence]
It is a value measured using a Berek compensator under crossed Nicols using a polarizing microscope.
偏光顕微鏡を使用し、直交ニコル下でベレックコンペンセータを用いて測定された値である。 [Birefringence]
It is a value measured using a Berek compensator under crossed Nicols using a polarizing microscope.
［弾性回復率］
ＰＥ原反の弾性回復率は、次の式（１）による。５０％伸長後荷重０となった時の長さは、２５℃、６５％相対湿度において試料（幅１５ｍｍ、長さ２インチ）を引張試験機にセットし、２インチ／ｍｉｎの速度で５０％まで伸長した後、１分間伸長状態で保持しその後同速度で弛緩させたものを測定した。 [Elastic recovery rate]
The elastic recovery rate of the PE original fabric is according to the following formula (1). When the load becomes 0 after 50% elongation, the length (width 15 mm,length 2 inches) is set in a tensile tester at 25 ° C. and 65% relative humidity, and 50% at a speed of 2 inches / min. The sample was stretched to 1 minute, held in the stretched state for 1 minute, and then relaxed at the same speed.
ＰＥ原反の弾性回復率は、次の式（１）による。５０％伸長後荷重０となった時の長さは、２５℃、６５％相対湿度において試料（幅１５ｍｍ、長さ２インチ）を引張試験機にセットし、２インチ／ｍｉｎの速度で５０％まで伸長した後、１分間伸長状態で保持しその後同速度で弛緩させたものを測定した。 [Elastic recovery rate]
The elastic recovery rate of the PE original fabric is according to the following formula (1). When the load becomes 0 after 50% elongation, the length (width 15 mm,
弾性回復率（％）＝［（５０％伸長時の長さ－５０％伸長後荷重０となった時の長さ）／（５０％伸長時の長さ－伸長前の長さ）］×１００ （１）
Elastic recovery rate (%) = [(length at 50% elongation−length at 50% elongation after zero load) / (length at 50% elongation−length before elongation)] × 100 (1)
ＰＰ原反の弾性回復率は、次の（２）による。１００％伸長後荷重０となった時の長さは、２５℃、６５％相対湿度において試料（幅１０ｍｍ、長さ５０ｍｍ）を引張試験機にセットし、５０ｍｍ／ｍｉｎの速度で１００％まで伸長した後、直ちに同速度で弛緩させ、１５０℃で３０分熱処理したものを測定した。
The elastic recovery rate of the PP original fabric is according to (2) below. When the load reaches 0 after 100% elongation, the sample (width 10 mm, length 50 mm) is set in a tensile tester at 25 ° C and 65% relative humidity, and stretched to 100% at a speed of 50 mm / min. After that, the sample was immediately relaxed at the same rate and heat-treated at 150 ° C. for 30 minutes.
弾性回復率（％）＝［（１００％伸長時の長さ－１００％伸長後荷重０となった時の長さ）／伸長前の長さ］×１００ （２）
Elastic recovery rate (%) = [(Length when 100% stretched-Length when load becomes 0 after 100% stretching) / Length before stretching] x 100 (2)
［融解熱量］
パーキンエルマー社製入力補償型ＤＳＣ（商品名：Ｄｉａｍｏｎｄ ＤＳＣ）を用いてＩＳＯ３１４６に準じ、走査温度範囲３０℃から２５０℃まで、昇温速度１０℃／分で昇温し昇温走査後に１０分間の熱処理を行った。その後、降温速度１０℃／分で走査温度下限まで降温させ、再び昇温速度１０℃／分で走査温度上限まで走査を行い、その際の吸熱ピークのピークトップ温度を融点とし、その時の熱量を融解熱量とした。 [Heat of fusion]
In accordance with ISO 3146, using a perkin elmer input compensation type DSC (trade name: Diamond DSC), the temperature is raised from a scanning temperature range of 30 ° C. to 250 ° C. at a heating rate of 10 ° C./min. Heat treatment was performed. Thereafter, the temperature is lowered to the lower limit of the scanning temperature at a temperature lowering rate of 10 ° C./min, and the scanning is performed again to the upper limit of the scanning temperature at the temperature rising rate of 10 ° C./min, and the peak top temperature of the endothermic peak at that time is taken as the melting point. It was set as the heat of fusion.
パーキンエルマー社製入力補償型ＤＳＣ（商品名：Ｄｉａｍｏｎｄ ＤＳＣ）を用いてＩＳＯ３１４６に準じ、走査温度範囲３０℃から２５０℃まで、昇温速度１０℃／分で昇温し昇温走査後に１０分間の熱処理を行った。その後、降温速度１０℃／分で走査温度下限まで降温させ、再び昇温速度１０℃／分で走査温度上限まで走査を行い、その際の吸熱ピークのピークトップ温度を融点とし、その時の熱量を融解熱量とした。 [Heat of fusion]
In accordance with ISO 3146, using a perkin elmer input compensation type DSC (trade name: Diamond DSC), the temperature is raised from a scanning temperature range of 30 ° C. to 250 ° C. at a heating rate of 10 ° C./min. Heat treatment was performed. Thereafter, the temperature is lowered to the lower limit of the scanning temperature at a temperature lowering rate of 10 ° C./min, and the scanning is performed again to the upper limit of the scanning temperature at the temperature rising rate of 10 ° C./min, and the peak top temperature of the endothermic peak at that time is taken as the melting point. It was set as the heat of fusion.
［重量平均分子量および分子量分布］
ＰＥ原反の原料として用いたＰＥ、およびＰＰ原反の原料として用いたＰＰの重量平均分子量および分子量分布は、Ｗａｔｅｒｓ社製Ｖ２００型ゲル浸透クロマトグラフを用いて、標準ポリスチレン換算によって求めた。カラムにはＳｈｏｄｅｘＡＴ－Ｇ＋ＡＴ８０６ＭＳの２本を使用し、０．３wt／vol％に調製したオルトジクロロベンゼン中、１４５℃で測定を行った。検出器には、示差屈折計（ＲＩ）を用いた。 [Weight average molecular weight and molecular weight distribution]
The weight average molecular weight and molecular weight distribution of PE used as a raw material for PE raw material and PP used as a raw material for PP raw material were determined by standard polystyrene conversion using a Waters V200 type gel permeation chromatograph. Two columns of ShodexAT-G + AT806MS were used for the column, and measurement was performed at 145 ° C. in orthodichlorobenzene prepared to 0.3 wt / vol%. A differential refractometer (RI) was used as the detector.
ＰＥ原反の原料として用いたＰＥ、およびＰＰ原反の原料として用いたＰＰの重量平均分子量および分子量分布は、Ｗａｔｅｒｓ社製Ｖ２００型ゲル浸透クロマトグラフを用いて、標準ポリスチレン換算によって求めた。カラムにはＳｈｏｄｅｘＡＴ－Ｇ＋ＡＴ８０６ＭＳの２本を使用し、０．３wt／vol％に調製したオルトジクロロベンゼン中、１４５℃で測定を行った。検出器には、示差屈折計（ＲＩ）を用いた。 [Weight average molecular weight and molecular weight distribution]
The weight average molecular weight and molecular weight distribution of PE used as a raw material for PE raw material and PP used as a raw material for PP raw material were determined by standard polystyrene conversion using a Waters V200 type gel permeation chromatograph. Two columns of ShodexAT-G + AT806MS were used for the column, and measurement was performed at 145 ° C. in orthodichlorobenzene prepared to 0.3 wt / vol%. A differential refractometer (RI) was used as the detector.
［透気度（ガーレ値）の測定］
製造したポリオレフィン微多孔膜または蓄電デバイス用セパレータフィルムからＭＤ方向に８０ｍｍ、全幅の試験片を採取し、中央部と左右の端部（端面から５０ｍｍ内側）の３点について、Ｂ型ガーレ式デンソメーター（株式会社東洋精機社製）を用い、ＪＩＳ Ｐ８１１７に準じて、測定を行った。３点の平均値をガーレ値として評価した。 [Measurement of air permeability (Gurley value)]
A test piece of 80 mm in the MD direction and full width was collected from the manufactured polyolefin microporous membrane or separator film for power storage device, and B-type Gurley type densometer at the center and left and right ends (inside 50 mm from the end face). (Toyo Seiki Co., Ltd.) was used and the measurement was performed according to JIS P8117. The average value of 3 points was evaluated as the Gurley value.
製造したポリオレフィン微多孔膜または蓄電デバイス用セパレータフィルムからＭＤ方向に８０ｍｍ、全幅の試験片を採取し、中央部と左右の端部（端面から５０ｍｍ内側）の３点について、Ｂ型ガーレ式デンソメーター（株式会社東洋精機社製）を用い、ＪＩＳ Ｐ８１１７に準じて、測定を行った。３点の平均値をガーレ値として評価した。 [Measurement of air permeability (Gurley value)]
A test piece of 80 mm in the MD direction and full width was collected from the manufactured polyolefin microporous membrane or separator film for power storage device, and B-type Gurley type densometer at the center and left and right ends (inside 50 mm from the end face). (Toyo Seiki Co., Ltd.) was used and the measurement was performed according to JIS P8117. The average value of 3 points was evaluated as the Gurley value.
［引張強度、引張伸度の測定］
ＡＳＴＭ Ｄ－８２２に準じ、測定を行った。
幅方向（ＴＤ）に延びる幅１０ｍｍ、長さ１００ｍｍの短冊状の試験片と、長さ方向（ＭＤ）に延びる幅１０ｍｍ、長さ１００ｍｍの短冊状の試験片とを、それぞれ試料の幅方向（ＴＤ）中央部と左右の端部（端面から１０ｍｍ内側の位置を試験片のＴＤ方向端面とする）の３点から採取した。 [Measurement of tensile strength and tensile elongation]
Measurements were performed according to ASTM D-822.
A strip-shaped specimen having a width of 10 mm and a length of 100 mm extending in the width direction (TD) and a strip-shaped specimen having a width of 10 mm and a length of 100 mm extending in the length direction (MD) are respectively measured in the width direction of the sample ( TD) Samples were collected from three points: a central portion and left and right end portions (a position on theinner side 10 mm from the end surface is the end surface in the TD direction of the test piece).
ＡＳＴＭ Ｄ－８２２に準じ、測定を行った。
幅方向（ＴＤ）に延びる幅１０ｍｍ、長さ１００ｍｍの短冊状の試験片と、長さ方向（ＭＤ）に延びる幅１０ｍｍ、長さ１００ｍｍの短冊状の試験片とを、それぞれ試料の幅方向（ＴＤ）中央部と左右の端部（端面から１０ｍｍ内側の位置を試験片のＴＤ方向端面とする）の３点から採取した。 [Measurement of tensile strength and tensile elongation]
Measurements were performed according to ASTM D-822.
A strip-shaped specimen having a width of 10 mm and a length of 100 mm extending in the width direction (TD) and a strip-shaped specimen having a width of 10 mm and a length of 100 mm extending in the length direction (MD) are respectively measured in the width direction of the sample ( TD) Samples were collected from three points: a central portion and left and right end portions (a position on the
引張試験機－ＯＲＩＥＮＴＥＣ．ＲＴＣ－１２１０Ａにて、１００Ｎのロードセルを用い、チャック間距離５０ｍｍ、クロスヘッドスピード５０ｍｍ／ｍｉｎ．の条件にて引張試験を実施した。
Tensile tester-ORIENTEC. In RTC-1210A, a 100N load cell was used, the distance between chucks was 50 mm, and the crosshead speed was 50 mm / min. The tensile test was carried out under the following conditions.
引張強度は試験片破断時の荷重Ｗ（ｋｇ）、試験片の断面積Ｓ（ｍｍ２、厚さは膜厚測定の平均値を用いる）から以下の式より算出した。
The tensile strength was calculated from the following formula from the load W (kg) when the test piece was broken and the cross-sectional area S of the test piece (mm 2 , and the thickness used the average value of the film thickness measurement).
［引張伸度］
引張伸度は試験前の試験片の標点間距離Ｌ０（ｍｍ）、破断時の標点間距離Ｌ（ｍｍ）から以下の式より算出した。 [Tensile elongation]
The tensile elongation was calculated from the following formula from the distance L 0 (mm) between the gauge points of the test piece before the test and the distance L (mm) between the gauge points at break.
引張伸度は試験前の試験片の標点間距離Ｌ０（ｍｍ）、破断時の標点間距離Ｌ（ｍｍ）から以下の式より算出した。 [Tensile elongation]
The tensile elongation was calculated from the following formula from the distance L 0 (mm) between the gauge points of the test piece before the test and the distance L (mm) between the gauge points at break.
各測定値の平均値を引張強度、引張伸度として評価した。
The average value of each measured value was evaluated as tensile strength and tensile elongation.
［突刺強度］
製造したポリオレフィン微多孔膜または蓄電デバイス用セパレータフィルムから、ＭＤ方向に約３０ｍｍ、ＴＤ方向に全幅にわたるテープ状の試験片を取採した。
カトーテック株式会社製、ハンディー圧縮試験機にＲ＝０．５ｍｍのニードル試験アタッチメントを装着し、９０ｍｍ／ｍｉｎの速度で、固定された試験片の中心を突いたときに、試験片が破れる荷重を測定した。
測定は２０点行い、２０点の平均を持って突刺強度とした。 [Puncture strength]
A tape-shaped test piece covering about 30 mm in the MD direction and the entire width in the TD direction was taken from the produced polyolefin microporous membrane or separator film for an electricity storage device.
Install a needle test attachment of R = 0.5mm on a handy compression tester manufactured by Kato Tech Co., Ltd. and load the test piece to break when it strikes the center of the fixed test piece at a speed of 90mm / min. It was measured.
Measurement was performed at 20 points, and the average of 20 points was taken as the puncture strength.
製造したポリオレフィン微多孔膜または蓄電デバイス用セパレータフィルムから、ＭＤ方向に約３０ｍｍ、ＴＤ方向に全幅にわたるテープ状の試験片を取採した。
カトーテック株式会社製、ハンディー圧縮試験機にＲ＝０．５ｍｍのニードル試験アタッチメントを装着し、９０ｍｍ／ｍｉｎの速度で、固定された試験片の中心を突いたときに、試験片が破れる荷重を測定した。
測定は２０点行い、２０点の平均を持って突刺強度とした。 [Puncture strength]
A tape-shaped test piece covering about 30 mm in the MD direction and the entire width in the TD direction was taken from the produced polyolefin microporous membrane or separator film for an electricity storage device.
Install a needle test attachment of R = 0.5mm on a handy compression tester manufactured by Kato Tech Co., Ltd. and load the test piece to break when it strikes the center of the fixed test piece at a speed of 90mm / min. It was measured.
Measurement was performed at 20 points, and the average of 20 points was taken as the puncture strength.
［目付重量］
試料より幅方向に両サイドより型枠を用い１００ｍｍ×１００ｍｍの試験片を２枚採取し、採取した２枚の各試験片の重量を測定した。
測定した重量から以下の式より目付重量を算出した。 [Weight per unit]
Two 100 mm × 100 mm test pieces were sampled from both sides in the width direction from the sample, and the weights of the two collected test pieces were measured.
Based on the measured weight, the weight per unit area was calculated from the following formula.
試料より幅方向に両サイドより型枠を用い１００ｍｍ×１００ｍｍの試験片を２枚採取し、採取した２枚の各試験片の重量を測定した。
測定した重量から以下の式より目付重量を算出した。 [Weight per unit]
Two 100 mm × 100 mm test pieces were sampled from both sides in the width direction from the sample, and the weights of the two collected test pieces were measured.
Based on the measured weight, the weight per unit area was calculated from the following formula.
［空孔率］
試料の幅方向両端部より型枠を用いて１００ｍｍ×１００ｍｍの試験片を、両端面に沿って２枚採取し、採取した２枚の各試験片の重量を０．１ｍｇ迄測定した。
測定した重量から以下の式を用いて空孔率を算出した。なお、式中の密度は多孔化前の試料の密度である。多孔化前の試料の密度は、試料中のＰＰ層の密度を０．９１ｇ／ｃｍ３とし、ＰＥ層の密度を０．９６４ｇ／ｃｍ３として下記の式により算出した。
多孔化前の試料の密度（ｇ／ｃｍ３）＝試料中のＰＰ層の割合×０．９１＋（１－試料中のＰＰ層の割合）×０．９６４ [Porosity]
Two test pieces of 100 mm × 100 mm were collected from both end portions in the width direction of the sample along the both end surfaces using a mold, and the weight of each of the collected two test pieces was measured to 0.1 mg.
The porosity was calculated from the measured weight using the following formula. In addition, the density in a type | formula is a density of the sample before porosity. The density of the sample before the porosity was calculated by the following formula, assuming that the density of the PP layer in the sample was 0.91 g / cm 3 and the density of the PE layer was 0.964 g / cm 3 .
Density of sample before porosity (g / cm 3 ) = ratio of PP layer in sample × 0.91 + (1-ratio of PP layer in sample) × 0.964
試料の幅方向両端部より型枠を用いて１００ｍｍ×１００ｍｍの試験片を、両端面に沿って２枚採取し、採取した２枚の各試験片の重量を０．１ｍｇ迄測定した。
測定した重量から以下の式を用いて空孔率を算出した。なお、式中の密度は多孔化前の試料の密度である。多孔化前の試料の密度は、試料中のＰＰ層の密度を０．９１ｇ／ｃｍ３とし、ＰＥ層の密度を０．９６４ｇ／ｃｍ３として下記の式により算出した。
多孔化前の試料の密度（ｇ／ｃｍ３）＝試料中のＰＰ層の割合×０．９１＋（１－試料中のＰＰ層の割合）×０．９６４ [Porosity]
Two test pieces of 100 mm × 100 mm were collected from both end portions in the width direction of the sample along the both end surfaces using a mold, and the weight of each of the collected two test pieces was measured to 0.1 mg.
The porosity was calculated from the measured weight using the following formula. In addition, the density in a type | formula is a density of the sample before porosity. The density of the sample before the porosity was calculated by the following formula, assuming that the density of the PP layer in the sample was 0.91 g / cm 3 and the density of the PE layer was 0.964 g / cm 3 .
Density of sample before porosity (g / cm 3 ) = ratio of PP layer in sample × 0.91 + (1-ratio of PP layer in sample) × 0.964
［加熱収縮率］
試料より試験片（２００×２００ｍｍ）を２枚採取した。１枚は、幅方向の一方の端部から１０ｍｍ内側の位置が、試験片の辺の位置となるように採取した。もう一枚は、幅方向のもう一方の端部から１０ｍｍ内側の位置が、試験片の辺の位置となるように採取した。
各試験片の幅方向（ＴＤ）及び長さ方向（ＭＤ）各１ヶ所に標点間距離１８０ｍｍの標点を中央部に記入し、標点間寸法を鋼尺にて測定した。標点間距離を記入した試料を紙に挟み、ヤマト科学製、熱風循環式 型式：ＤＫ－４３にて１０５℃にて２時間加熱処理を行った。加熱処理された試料を紙に挟んだまま取り出し、室温にて６０分間放冷を行い、標点間距離を鋼尺にて測定した。２枚の試験片について、それぞれＴＤ方向およびＭＤ方向の加熱による収縮率を算出し、２枚の試験片の平均値を加熱収縮率とした。 [Heating shrinkage]
Two test pieces (200 × 200 mm) were collected from the sample. One piece was collected so that theposition 10 mm inside from one end in the width direction was the position of the side of the test piece. The other sheet was taken so that the position 10 mm inside from the other end in the width direction was the position of the side of the test piece.
A gauge point with a distance between the gauge points of 180 mm was written in the center in each of the width direction (TD) and the length direction (MD) of each test piece, and the dimension between the gauge points was measured with a steel scale. A sample in which the distance between the gauge points was recorded was sandwiched between papers, and heat treatment was carried out at 105 ° C. for 2 hours using Yamato Kagaku's hot air circulation model: DK-43. The heat-treated sample was taken out while being sandwiched between papers, allowed to cool at room temperature for 60 minutes, and the distance between the gauge points was measured with a steel rule. About two test pieces, the shrinkage rate by the heating of TD direction and MD direction was calculated, respectively, and the average value of the two test pieces was made into the heat shrinkage rate.
試料より試験片（２００×２００ｍｍ）を２枚採取した。１枚は、幅方向の一方の端部から１０ｍｍ内側の位置が、試験片の辺の位置となるように採取した。もう一枚は、幅方向のもう一方の端部から１０ｍｍ内側の位置が、試験片の辺の位置となるように採取した。
各試験片の幅方向（ＴＤ）及び長さ方向（ＭＤ）各１ヶ所に標点間距離１８０ｍｍの標点を中央部に記入し、標点間寸法を鋼尺にて測定した。標点間距離を記入した試料を紙に挟み、ヤマト科学製、熱風循環式 型式：ＤＫ－４３にて１０５℃にて２時間加熱処理を行った。加熱処理された試料を紙に挟んだまま取り出し、室温にて６０分間放冷を行い、標点間距離を鋼尺にて測定した。２枚の試験片について、それぞれＴＤ方向およびＭＤ方向の加熱による収縮率を算出し、２枚の試験片の平均値を加熱収縮率とした。 [Heating shrinkage]
Two test pieces (200 × 200 mm) were collected from the sample. One piece was collected so that the
A gauge point with a distance between the gauge points of 180 mm was written in the center in each of the width direction (TD) and the length direction (MD) of each test piece, and the dimension between the gauge points was measured with a steel scale. A sample in which the distance between the gauge points was recorded was sandwiched between papers, and heat treatment was carried out at 105 ° C. for 2 hours using Yamato Kagaku's hot air circulation model: DK-43. The heat-treated sample was taken out while being sandwiched between papers, allowed to cool at room temperature for 60 minutes, and the distance between the gauge points was measured with a steel rule. About two test pieces, the shrinkage rate by the heating of TD direction and MD direction was calculated, respectively, and the average value of the two test pieces was made into the heat shrinkage rate.
加熱収縮率は加熱前標点間距離をＬ１（ｍｍ）、加熱後の標点間距離をＬ２（ｍｍ）とし以下の式により算出した。
熱収縮率＝（Ｌ１－Ｌ２）／Ｌ１×１００ The heat shrinkage rate was calculated by the following formula, assuming that the distance between the pre-heating marks was L 1 (mm) and the distance between the marks after heating was L 2 (mm).
Thermal contraction rate = (L 1 −L 2 ) / L 1 × 100
熱収縮率＝（Ｌ１－Ｌ２）／Ｌ１×１００ The heat shrinkage rate was calculated by the following formula, assuming that the distance between the pre-heating marks was L 1 (mm) and the distance between the marks after heating was L 2 (mm).
Thermal contraction rate = (L 1 −L 2 ) / L 1 × 100
［オーブン加熱試験］
図２Ａに示すように、試料２を縦６０ｍｍ×横６０ｍｍ角に切り出し、中央部にφ４０ｍｍの円状の穴を空けたアルミ板１（材質：ＪＩＳ規格Ａ５０５２、サイズ：縦６０ｍｍ、横６０ｍｍ、厚さ１ｍｍ）２枚の間にはさみ、図２Ｂに示すように周囲をクリップ３（ＫＯＫＵＹＯ社製、ダブルクリップ「クリ－Ｊ３５」）で固定した。
アルミ板２枚で固定された状態の試料２を２００℃に設定したオ－ブン（ＥＳＰＥＣ社製、ＰＨ－２０１、ダンパー閉状態）に入れ、オーブン設定温度が２００℃に再び達してから２分後に取り出し、試料の状態からメルトダウン（ＭＤ）特性の有無を評価した。 [Oven heating test]
As shown in FIG. 2A, an aluminum plate 1 (sample: JIS standard A5052, size: length 60 mm, width 60 mm, thickness), which is obtained by cutting thesample 2 into a 60 mm × 60 mm square and having a circular hole of φ40 mm at the center. 2 mm), and the periphery was fixed with a clip 3 (manufactured by KOKUYO, double clip “Kuri-J35”) as shown in FIG. 2B.
Sample 2 fixed with two aluminum plates is placed in an oven set to 200 ° C (manufactured by ESPEC, PH-201, damper closed), and 2 minutes after the oven set temperature reaches 200 ° C again It was taken out later and the presence or absence of meltdown (MD) characteristics was evaluated from the state of the sample.
図２Ａに示すように、試料２を縦６０ｍｍ×横６０ｍｍ角に切り出し、中央部にφ４０ｍｍの円状の穴を空けたアルミ板１（材質：ＪＩＳ規格Ａ５０５２、サイズ：縦６０ｍｍ、横６０ｍｍ、厚さ１ｍｍ）２枚の間にはさみ、図２Ｂに示すように周囲をクリップ３（ＫＯＫＵＹＯ社製、ダブルクリップ「クリ－Ｊ３５」）で固定した。
アルミ板２枚で固定された状態の試料２を２００℃に設定したオ－ブン（ＥＳＰＥＣ社製、ＰＨ－２０１、ダンパー閉状態）に入れ、オーブン設定温度が２００℃に再び達してから２分後に取り出し、試料の状態からメルトダウン（ＭＤ）特性の有無を評価した。 [Oven heating test]
As shown in FIG. 2A, an aluminum plate 1 (sample: JIS standard A5052, size: length 60 mm, width 60 mm, thickness), which is obtained by cutting the
○：形状が維持されている場合（ＭＤ特性あり）
×：形状が維持できず、破膜した場合（ＭＤ特性なし）
なお、フィルム片が６０ｍｍ×６０ｍｍ角に切り出せない場合は、中央部がφ４０ｍｍの円状の穴にフィルムが設置されるように調整し、試料を作成しても構わない。 ○: When the shape is maintained (with MD characteristics)
×: When the shape cannot be maintained and the film breaks (no MD characteristics)
If the film piece cannot be cut into a 60 mm × 60 mm square, the sample may be prepared by adjusting the film so that the film is placed in a circular hole having a central portion of φ40 mm.
×：形状が維持できず、破膜した場合（ＭＤ特性なし）
なお、フィルム片が６０ｍｍ×６０ｍｍ角に切り出せない場合は、中央部がφ４０ｍｍの円状の穴にフィルムが設置されるように調整し、試料を作成しても構わない。 ○: When the shape is maintained (with MD characteristics)
×: When the shape cannot be maintained and the film breaks (no MD characteristics)
If the film piece cannot be cut into a 60 mm × 60 mm square, the sample may be prepared by adjusting the film so that the film is placed in a circular hole having a central portion of φ40 mm.
［シャットダウン・メルトダウン温度］
自製の電気抵抗測定用セルを用いて、シャットダウン温度、メルトダウン温度を測定した。体積比でプロピレンカーボネート（ＰＣ）とジエチルカーボネート（ＤＥＣ）をＰＣ／ＤＥＣ＝３／７で混合した混合溶媒を調製した。前記混合溶媒に対し１ｍｏｌ／Ｌの濃度になるように六フッ化燐酸リチウムが溶解した電解液を、製造したポリオレフィン微多孔膜または蓄電デバイス用セパレータフィルムに含浸させ、セパレータ試料片とした。ニッケル製電極に電解液を含浸させたセパレータ試料片を挟み、１０℃／ｍｉｎの速度で昇温した。電極間抵抗は抵抗測定装置：ＬＣＲハイテスタ（日置電気（株）製）を用いて、測定周波数１ｋＨｚの条件で行った。このとき、電気抵抗が１０００Ωに達した温度をシャットダウン温度とした。また、シャットダウン温度後も２３０℃まで昇温を続けて、短絡が生じるかを確認し、短絡が生じた温度をメルトダウン温度とした。 [Shutdown / meltdown temperature]
Using a self-made cell for measuring electrical resistance, the shutdown temperature and the meltdown temperature were measured. A mixed solvent in which propylene carbonate (PC) and diethyl carbonate (DEC) were mixed at a volume ratio of PC / DEC = 3/7 was prepared. An electrolyte solution in which lithium hexafluorophosphate was dissolved so as to have a concentration of 1 mol / L with respect to the mixed solvent was impregnated into the produced polyolefin microporous membrane or the separator film for an electricity storage device to obtain a separator sample piece. A separator sample piece impregnated with an electrolytic solution was sandwiched between nickel electrodes, and the temperature was increased at a rate of 10 ° C./min. The interelectrode resistance was measured under the condition of a measurement frequency of 1 kHz using a resistance measuring device: LCR HiTester (manufactured by Hioki Electric Co., Ltd.). At this time, the temperature at which the electrical resistance reached 1000Ω was taken as the shutdown temperature. Further, the temperature was continuously raised to 230 ° C. even after the shutdown temperature to check whether a short circuit occurred, and the temperature at which the short circuit occurred was defined as the meltdown temperature.
自製の電気抵抗測定用セルを用いて、シャットダウン温度、メルトダウン温度を測定した。体積比でプロピレンカーボネート（ＰＣ）とジエチルカーボネート（ＤＥＣ）をＰＣ／ＤＥＣ＝３／７で混合した混合溶媒を調製した。前記混合溶媒に対し１ｍｏｌ／Ｌの濃度になるように六フッ化燐酸リチウムが溶解した電解液を、製造したポリオレフィン微多孔膜または蓄電デバイス用セパレータフィルムに含浸させ、セパレータ試料片とした。ニッケル製電極に電解液を含浸させたセパレータ試料片を挟み、１０℃／ｍｉｎの速度で昇温した。電極間抵抗は抵抗測定装置：ＬＣＲハイテスタ（日置電気（株）製）を用いて、測定周波数１ｋＨｚの条件で行った。このとき、電気抵抗が１０００Ωに達した温度をシャットダウン温度とした。また、シャットダウン温度後も２３０℃まで昇温を続けて、短絡が生じるかを確認し、短絡が生じた温度をメルトダウン温度とした。 [Shutdown / meltdown temperature]
Using a self-made cell for measuring electrical resistance, the shutdown temperature and the meltdown temperature were measured. A mixed solvent in which propylene carbonate (PC) and diethyl carbonate (DEC) were mixed at a volume ratio of PC / DEC = 3/7 was prepared. An electrolyte solution in which lithium hexafluorophosphate was dissolved so as to have a concentration of 1 mol / L with respect to the mixed solvent was impregnated into the produced polyolefin microporous membrane or the separator film for an electricity storage device to obtain a separator sample piece. A separator sample piece impregnated with an electrolytic solution was sandwiched between nickel electrodes, and the temperature was increased at a rate of 10 ° C./min. The interelectrode resistance was measured under the condition of a measurement frequency of 1 kHz using a resistance measuring device: LCR HiTester (manufactured by Hioki Electric Co., Ltd.). At this time, the temperature at which the electrical resistance reached 1000Ω was taken as the shutdown temperature. Further, the temperature was continuously raised to 230 ° C. even after the shutdown temperature to check whether a short circuit occurred, and the temperature at which the short circuit occurred was defined as the meltdown temperature.
［耐電圧試験（短絡試験）］
株式会社サンコウ電子研究所社製ピンホール試験機ＴＯ－５ＤＰ型を用い、検査電圧０．３ｋＶと０．５ｋＶの条件で、サンプルサイズ１０ｃｍ×１００ｃｍの面積についてプローブを接触させながら走査し、耐電圧試験を実施した。評価結果は、○、×で判別した。
○：通電箇所無し。
×：通電箇所、1か所以上あり。 [Withstand voltage test (short circuit test)]
Using a pinhole tester TO-5DP manufactured by Sanko Electronics Laboratory Co., Ltd., scanning with a probe in contact with an area of sample size 10cm x 100cm under the conditions of inspection voltage 0.3kV and 0.5kV, withstand voltage The test was conducted. The evaluation results were determined by ○ and ×.
○: There is no energized part.
×: There are one or more energized locations.
株式会社サンコウ電子研究所社製ピンホール試験機ＴＯ－５ＤＰ型を用い、検査電圧０．３ｋＶと０．５ｋＶの条件で、サンプルサイズ１０ｃｍ×１００ｃｍの面積についてプローブを接触させながら走査し、耐電圧試験を実施した。評価結果は、○、×で判別した。
○：通電箇所無し。
×：通電箇所、1か所以上あり。 [Withstand voltage test (short circuit test)]
Using a pinhole tester TO-5DP manufactured by Sanko Electronics Laboratory Co., Ltd., scanning with a probe in contact with an area of sample size 10cm x 100cm under the conditions of inspection voltage 0.3kV and 0.5kV, withstand voltage The test was conducted. The evaluation results were determined by ○ and ×.
○: There is no energized part.
×: There are one or more energized locations.
［表面開口率の測定方法］
ポリオレフィン微多孔膜の表面ＳＥＭ観察を行い、その画像をＩｍａｇｅ Jで２値化した。その画像において、開口部を黒色、未開口部を白色として分離し、１０μｍ×１０μｍの範囲の面積を４箇所画像解析し、それぞれ開口部の総面積を算出した。算出した各開口部の総面積から平均値を求め、画像解析を実施した面積で除して、百分率で評価した。 [Measurement method of surface aperture ratio]
Surface SEM observation of the polyolefin microporous membrane was performed, and the image was binarized with Image J. In the image, the opening was separated into black and the non-opening was separated into white, and image analysis was performed on four areas in the range of 10 μm × 10 μm, and the total area of the openings was calculated. An average value was obtained from the calculated total area of each opening, divided by the area where image analysis was performed, and evaluated as a percentage.
ポリオレフィン微多孔膜の表面ＳＥＭ観察を行い、その画像をＩｍａｇｅ Jで２値化した。その画像において、開口部を黒色、未開口部を白色として分離し、１０μｍ×１０μｍの範囲の面積を４箇所画像解析し、それぞれ開口部の総面積を算出した。算出した各開口部の総面積から平均値を求め、画像解析を実施した面積で除して、百分率で評価した。 [Measurement method of surface aperture ratio]
Surface SEM observation of the polyolefin microporous membrane was performed, and the image was binarized with Image J. In the image, the opening was separated into black and the non-opening was separated into white, and image analysis was performed on four areas in the range of 10 μm × 10 μm, and the total area of the openings was calculated. An average value was obtained from the calculated total area of each opening, divided by the area where image analysis was performed, and evaluated as a percentage.
［ゼロ剪断粘度］
ＴＡインスツルメント社製のレオメータＡＲＥＳ（型式：ＡＲＥＳ）を用いて、溶融ＰＰ樹脂のせん断動的粘弾性測定を行った。ジオメトリには、コーン－パラレルプレート（コーン角０．１ｒａｄ）を用いた。周波数範囲４００～０．０１ｓ－１（５ｐｏｉｎｔｓ ｐｅｒ ｄｅｃａｄｅ）、ひずみ０．１（１０％）の条件で、温度２２０℃、２００℃、１８０℃、１６０℃の４水準について動的粘弾性測定を行い、２００℃の測定データを基準としてマスターカーブを作成した。周波数０．０１ｓ－１以下の領域において、一定値となった粘度の値をゼロ剪断粘度とした。なお本明細書では、上述した２００℃の測定データを基準としてマスターカーブを作成し、このマスターカーブに基づいてゼロ剪断粘度を算出することを「２００℃条件」という。 [Zero shear viscosity]
The shear dynamic viscoelasticity measurement of the molten PP resin was performed using a rheometer ARES (model: ARES) manufactured by TA Instruments. The geometry used was a cone-parallel plate (cone angle 0.1 rad). Dynamic viscoelasticity measurements were performed at four levels of 220 ° C, 200 ° C, 180 ° C, and 160 ° C under conditions of a frequency range of 400 to 0.01 s -1 (5 points per decade) and a strain of 0.1 (10%). A master curve was created based on measurement data at 200 ° C. In the region where the frequency was 0.01 s −1 or less, the value of the viscosity that became a constant value was defined as zero shear viscosity. In the present specification, creating a master curve based on the above-described measurement data at 200 ° C. and calculating the zero shear viscosity based on the master curve is referred to as “200 ° C. condition”.
ＴＡインスツルメント社製のレオメータＡＲＥＳ（型式：ＡＲＥＳ）を用いて、溶融ＰＰ樹脂のせん断動的粘弾性測定を行った。ジオメトリには、コーン－パラレルプレート（コーン角０．１ｒａｄ）を用いた。周波数範囲４００～０．０１ｓ－１（５ｐｏｉｎｔｓ ｐｅｒ ｄｅｃａｄｅ）、ひずみ０．１（１０％）の条件で、温度２２０℃、２００℃、１８０℃、１６０℃の４水準について動的粘弾性測定を行い、２００℃の測定データを基準としてマスターカーブを作成した。周波数０．０１ｓ－１以下の領域において、一定値となった粘度の値をゼロ剪断粘度とした。なお本明細書では、上述した２００℃の測定データを基準としてマスターカーブを作成し、このマスターカーブに基づいてゼロ剪断粘度を算出することを「２００℃条件」という。 [Zero shear viscosity]
The shear dynamic viscoelasticity measurement of the molten PP resin was performed using a rheometer ARES (model: ARES) manufactured by TA Instruments. The geometry used was a cone-parallel plate (cone angle 0.1 rad). Dynamic viscoelasticity measurements were performed at four levels of 220 ° C, 200 ° C, 180 ° C, and 160 ° C under conditions of a frequency range of 400 to 0.01 s -1 (5 points per decade) and a strain of 0.1 (10%). A master curve was created based on measurement data at 200 ° C. In the region where the frequency was 0.01 s −1 or less, the value of the viscosity that became a constant value was defined as zero shear viscosity. In the present specification, creating a master curve based on the above-described measurement data at 200 ° C. and calculating the zero shear viscosity based on the master curve is referred to as “200 ° C. condition”.
（実施例１）
以下に本発明のポリオレフィン微多孔膜の製造方法の一例について示すが、製造方法は以下に限らず他の方法を用いてもよい。例えば、以下の方法の他にも、Ｔダイを用いた共押し出し工程と延伸工程とでポリオレフィン微多孔膜を作製してもよい。 Example 1
Although an example of the manufacturing method of the polyolefin microporous membrane of the present invention is shown below, the manufacturing method is not limited to the following, and other methods may be used. For example, in addition to the following method, a polyolefin microporous film may be produced by a co-extrusion step using a T die and a stretching step.
以下に本発明のポリオレフィン微多孔膜の製造方法の一例について示すが、製造方法は以下に限らず他の方法を用いてもよい。例えば、以下の方法の他にも、Ｔダイを用いた共押し出し工程と延伸工程とでポリオレフィン微多孔膜を作製してもよい。 Example 1
Although an example of the manufacturing method of the polyolefin microporous membrane of the present invention is shown below, the manufacturing method is not limited to the following, and other methods may be used. For example, in addition to the following method, a polyolefin microporous film may be produced by a co-extrusion step using a T die and a stretching step.
［ＰＰ原反の製膜］
吐出幅１０００ｍｍ、吐出リップ開度２ｍｍのＴダイを使用し、重量平均分子量が５９０，０００、分子量分布が１１．０、ペンタッド分率が９２％、融点が１６１℃のポリプロピレン樹脂を、Ｔダイ温度２００℃で溶融押出した。吐出フィルムは９０℃の冷却ロ－ルに導かれ、３７．２℃の冷風が吹きつけられて冷却された後、４０ｍ／ｍｉｎ．で引き取った。得られた未延伸ポリプロピレンフィルム（ＰＰ原反）の膜厚は１４．１μｍ、複屈折は１５．０×１０－３、弾性回復率は１５０℃、３０分熱処理後で９０．０％であった。また、得られたＰＰ原反の原反の厚みに対する変動係数（Ｃ．Ｖ．）は、０．０１５であった。 [PP film formation]
Using a T-die with a discharge width of 1000 mm and a discharge lip opening of 2 mm, a polypropylene resin having a weight average molecular weight of 590,000, a molecular weight distribution of 11.0, a pentad fraction of 92%, and a melting point of 161 ° C. is used. Melt extrusion was performed at 200 ° C. The discharged film was guided to a cooling roll at 90 ° C., cooled with 37.2 ° C. cold air, and then cooled to 40 m / min. I picked it up. The film thickness of the obtained unstretched polypropylene film (PP raw fabric) was 14.1 μm, the birefringence was 15.0 × 10 −3 , and the elastic recovery was 90.0% after heat treatment at 150 ° C. for 30 minutes. . In addition, the coefficient of variation (CV) of the obtained PP original fabric with respect to the thickness of the original fabric was 0.015.
吐出幅１０００ｍｍ、吐出リップ開度２ｍｍのＴダイを使用し、重量平均分子量が５９０，０００、分子量分布が１１．０、ペンタッド分率が９２％、融点が１６１℃のポリプロピレン樹脂を、Ｔダイ温度２００℃で溶融押出した。吐出フィルムは９０℃の冷却ロ－ルに導かれ、３７．２℃の冷風が吹きつけられて冷却された後、４０ｍ／ｍｉｎ．で引き取った。得られた未延伸ポリプロピレンフィルム（ＰＰ原反）の膜厚は１４．１μｍ、複屈折は１５．０×１０－３、弾性回復率は１５０℃、３０分熱処理後で９０．０％であった。また、得られたＰＰ原反の原反の厚みに対する変動係数（Ｃ．Ｖ．）は、０．０１５であった。 [PP film formation]
Using a T-die with a discharge width of 1000 mm and a discharge lip opening of 2 mm, a polypropylene resin having a weight average molecular weight of 590,000, a molecular weight distribution of 11.0, a pentad fraction of 92%, and a melting point of 161 ° C. is used. Melt extrusion was performed at 200 ° C. The discharged film was guided to a cooling roll at 90 ° C., cooled with 37.2 ° C. cold air, and then cooled to 40 m / min. I picked it up. The film thickness of the obtained unstretched polypropylene film (PP raw fabric) was 14.1 μm, the birefringence was 15.0 × 10 −3 , and the elastic recovery was 90.0% after heat treatment at 150 ° C. for 30 minutes. . In addition, the coefficient of variation (CV) of the obtained PP original fabric with respect to the thickness of the original fabric was 0.015.
［ＰＥ原反の製膜］
吐出幅１０００ｍｍ、吐出リップ開度２ｍｍのＴダイを使用し、重量平均分子量が３２０，０００、分子量分布が７．８、密度が０．９６４ｇ／ｃｍ３、融点が１３３℃、メルトインデックス０．３１の高密度ポリエチレンを、１７３℃で溶融押出した。吐出フィルムは１１５℃の冷却ロ－ルに導かれ、３９℃の冷風を吹きつけて冷却した後、２０ｍ／ｍｉｎ．で引き取った。得られた未延伸ポリエチレンフィルム（ＰＥ原反）の膜厚は７．６μｍ、複屈折は３７．５×１０－３、５０％伸長時の弾性回復率は３８．５％であった。
また、得られたＰＥ原反の原反の厚みに対する変動係数（Ｃ．Ｖ．）は、０．０１６であった。 [PE film formation]
Using a T-die with a discharge width of 1000 mm and a discharge lip opening of 2 mm, a weight average molecular weight of 320,000, a molecular weight distribution of 7.8, a density of 0.964 g / cm 3 , a melting point of 133 ° C., a melt index of 0.31 Of high density polyethylene was melt extruded at 173 ° C. The discharged film was guided to a 115 ° C. cooling roll, cooled by blowing cold air of 39 ° C., and then 20 m / min. I picked it up. The film thickness of the obtained unstretched polyethylene film (PE raw fabric) was 7.6 μm, the birefringence was 37.5 × 10 −3 , and the elastic recovery at 50% elongation was 38.5%.
Moreover, the variation coefficient (CV) with respect to the thickness of the obtained PE original fabric was 0.016.
吐出幅１０００ｍｍ、吐出リップ開度２ｍｍのＴダイを使用し、重量平均分子量が３２０，０００、分子量分布が７．８、密度が０．９６４ｇ／ｃｍ３、融点が１３３℃、メルトインデックス０．３１の高密度ポリエチレンを、１７３℃で溶融押出した。吐出フィルムは１１５℃の冷却ロ－ルに導かれ、３９℃の冷風を吹きつけて冷却した後、２０ｍ／ｍｉｎ．で引き取った。得られた未延伸ポリエチレンフィルム（ＰＥ原反）の膜厚は７．６μｍ、複屈折は３７．５×１０－３、５０％伸長時の弾性回復率は３８．５％であった。
また、得られたＰＥ原反の原反の厚みに対する変動係数（Ｃ．Ｖ．）は、０．０１６であった。 [PE film formation]
Using a T-die with a discharge width of 1000 mm and a discharge lip opening of 2 mm, a weight average molecular weight of 320,000, a molecular weight distribution of 7.8, a density of 0.964 g / cm 3 , a melting point of 133 ° C., a melt index of 0.31 Of high density polyethylene was melt extruded at 173 ° C. The discharged film was guided to a 115 ° C. cooling roll, cooled by blowing cold air of 39 ° C., and then 20 m / min. I picked it up. The film thickness of the obtained unstretched polyethylene film (PE raw fabric) was 7.6 μm, the birefringence was 37.5 × 10 −3 , and the elastic recovery at 50% elongation was 38.5%.
Moreover, the variation coefficient (CV) with respect to the thickness of the obtained PE original fabric was 0.016.
［ラミネート工程］
この未延伸ＰＰ原反（ＰＰ原反）と未延伸ＰＥ原反（ＰＥ原反）とを使用し、両外層がＰＰで内層がＰＥのサンドイッチ構成の三層の積層フィルムを以下のようにして製造した。
三組の原反ロ－ルサンドから、ＰＰ原反とＰＰ原反をそれぞれ巻きだし速度６．５ｍ／ｍｉｎ．で巻きだし、加熱ロ－ルに導き、ロール温度１４７℃のロールにて熱圧着し、その後同速度で３０℃の冷却ロ－ルに導いた後に巻き取った。巻出し張力はＰＰ原反が５．０ｋｇ、ＰＥ原反が３．０ｋｇであった。得られた積層フィルムは膜厚３５．８μｍで、剥離強度は５７．９ｇ／１５ｍｍであった。 [Lamination process]
Using this unstretched PP original fabric (PP original fabric) and unstretched PE original fabric (PE original fabric), a three-layer laminated film having both outer layers PP and inner layers PE sandwiched as follows Manufactured.
From the three sets of roll roll sand, the PP roll and PP roll are unrolled at a speed of 6.5 m / min. Then, it was led to a heating roll, subjected to thermocompression bonding with a roll having a roll temperature of 147 ° C., and then led to a cooling roll at 30 ° C. at the same speed and then wound. The unwinding tension was 5.0 kg for PP and 3.0 kg for PE. The obtained laminated film had a film thickness of 35.8 μm and a peel strength of 57.9 g / 15 mm.
この未延伸ＰＰ原反（ＰＰ原反）と未延伸ＰＥ原反（ＰＥ原反）とを使用し、両外層がＰＰで内層がＰＥのサンドイッチ構成の三層の積層フィルムを以下のようにして製造した。
三組の原反ロ－ルサンドから、ＰＰ原反とＰＰ原反をそれぞれ巻きだし速度６．５ｍ／ｍｉｎ．で巻きだし、加熱ロ－ルに導き、ロール温度１４７℃のロールにて熱圧着し、その後同速度で３０℃の冷却ロ－ルに導いた後に巻き取った。巻出し張力はＰＰ原反が５．０ｋｇ、ＰＥ原反が３．０ｋｇであった。得られた積層フィルムは膜厚３５．８μｍで、剥離強度は５７．９ｇ／１５ｍｍであった。 [Lamination process]
Using this unstretched PP original fabric (PP original fabric) and unstretched PE original fabric (PE original fabric), a three-layer laminated film having both outer layers PP and inner layers PE sandwiched as follows Manufactured.
From the three sets of roll roll sand, the PP roll and PP roll are unrolled at a speed of 6.5 m / min. Then, it was led to a heating roll, subjected to thermocompression bonding with a roll having a roll temperature of 147 ° C., and then led to a cooling roll at 30 ° C. at the same speed and then wound. The unwinding tension was 5.0 kg for PP and 3.0 kg for PE. The obtained laminated film had a film thickness of 35.8 μm and a peel strength of 57.9 g / 15 mm.
［延伸工程］
この三層の積層フィルムは１２５℃に加熱された熱風循環オ－ブン（熱処理ゾーン：オーブン１）中に導かれ加熱処理を行った。次いで熱処理した積層フィルムは、冷延伸ゾーンにて、３５℃に保持されたニップロール間で１８％（初期延伸倍率）に低温延伸された。供給側のロ－ル速度は２．８ｍ／ｍｉｎ．であった。引き続き１３０℃に加熱された熱延伸ゾーン（オーブン２）にて、ロ－ル周速差を利用してロ－ラ間で１９０％（最大延伸倍率）になるまで熱延伸された後、引きつづき１２５％（最終延伸倍率）まで熱緩和させ、次いで熱固定ゾーン（オーブン３）にて、１３３℃にて熱固定され、連続的にＰＰ/ＰＥ/ＰＰ、３層構造のポリオレフィン微多孔膜を得た。 [Stretching process]
This three-layer laminated film was introduced into a hot air circulation oven (heat treatment zone: oven 1) heated to 125 ° C. and subjected to heat treatment. The heat-treated laminated film was then stretched at a low temperature of 18% (initial stretching ratio) between nip rolls maintained at 35 ° C. in a cold stretching zone. The roll speed on the supply side is 2.8 m / min. Met. In the hot drawing zone (Oven 2) heated to 130 ° C, the rolls were stretched to 190% (maximum draw ratio) between the rollers using the difference in the peripheral speed of the rolls. Heat relaxation to 125% (final draw ratio), then heat setting at 133 ° C. in a heat setting zone (oven 3), to obtain a polyolefin microporous membrane of PP / PE / PP, 3 layer structure continuously It was.
この三層の積層フィルムは１２５℃に加熱された熱風循環オ－ブン（熱処理ゾーン：オーブン１）中に導かれ加熱処理を行った。次いで熱処理した積層フィルムは、冷延伸ゾーンにて、３５℃に保持されたニップロール間で１８％（初期延伸倍率）に低温延伸された。供給側のロ－ル速度は２．８ｍ／ｍｉｎ．であった。引き続き１３０℃に加熱された熱延伸ゾーン（オーブン２）にて、ロ－ル周速差を利用してロ－ラ間で１９０％（最大延伸倍率）になるまで熱延伸された後、引きつづき１２５％（最終延伸倍率）まで熱緩和させ、次いで熱固定ゾーン（オーブン３）にて、１３３℃にて熱固定され、連続的にＰＰ/ＰＥ/ＰＰ、３層構造のポリオレフィン微多孔膜を得た。 [Stretching process]
This three-layer laminated film was introduced into a hot air circulation oven (heat treatment zone: oven 1) heated to 125 ° C. and subjected to heat treatment. The heat-treated laminated film was then stretched at a low temperature of 18% (initial stretching ratio) between nip rolls maintained at 35 ° C. in a cold stretching zone. The roll speed on the supply side is 2.8 m / min. Met. In the hot drawing zone (Oven 2) heated to 130 ° C, the rolls were stretched to 190% (maximum draw ratio) between the rollers using the difference in the peripheral speed of the rolls. Heat relaxation to 125% (final draw ratio), then heat setting at 133 ° C. in a heat setting zone (oven 3), to obtain a polyolefin microporous membrane of PP / PE / PP, 3 layer structure continuously It was.
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性を表１および表２に示した。
また、実施例１のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。
また、オーブン加熱試験のメルトダウン（ＭＤ）特性については、表３に示した。シャットダウン（ＳＤ）温度特性については、図１に示した。 Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane.
Table 2 shows the electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membrane of Example 1 was used as a separator film for an electricity storage device.
The melt down (MD) characteristics of the oven heating test are shown in Table 3. The shutdown (SD) temperature characteristic is shown in FIG.
また、実施例１のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。
また、オーブン加熱試験のメルトダウン（ＭＤ）特性については、表３に示した。シャットダウン（ＳＤ）温度特性については、図１に示した。 Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane.
Table 2 shows the electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membrane of Example 1 was used as a separator film for an electricity storage device.
The melt down (MD) characteristics of the oven heating test are shown in Table 3. The shutdown (SD) temperature characteristic is shown in FIG.
（実施例２～実施例６）
ＰＰ樹脂原料と、ＰＰ原反およびＰＥ原反の膜厚とを変更した以外は、実施例１と同様の方法でポリオレフィン微多孔膜を作製した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性を表１および表２に示した。実施例２～実施例６に使用したＰＰ樹脂は表１に記載した物性の原料を使用した。
また、実施例２～実施例６のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。 (Example 2 to Example 6)
A polyolefin microporous membrane was prepared in the same manner as in Example 1 except that the PP resin raw material and the film thickness of the PP raw material and the PE raw material were changed.
Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane. The PP resin used in Examples 2 to 6 was a raw material having physical properties described in Table 1.
Table 2 shows the electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membranes of Examples 2 to 6 were used as a separator film for an electricity storage device.
ＰＰ樹脂原料と、ＰＰ原反およびＰＥ原反の膜厚とを変更した以外は、実施例１と同様の方法でポリオレフィン微多孔膜を作製した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性を表１および表２に示した。実施例２～実施例６に使用したＰＰ樹脂は表１に記載した物性の原料を使用した。
また、実施例２～実施例６のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。 (Example 2 to Example 6)
A polyolefin microporous membrane was prepared in the same manner as in Example 1 except that the PP resin raw material and the film thickness of the PP raw material and the PE raw material were changed.
Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane. The PP resin used in Examples 2 to 6 was a raw material having physical properties described in Table 1.
Table 2 shows the electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membranes of Examples 2 to 6 were used as a separator film for an electricity storage device.
（実施例７）
多層原反装置を使用して３層構造（ＰＰ/ＰＥ/ＰＰ）の多層原反を作製し、ラミネート工程を省略した以外は、実施例１と同様の方法で作成した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性を表１および表２に示した。複屈折および弾性回復率は多層原反のまま測定を行った。また、弾性回復率は、ＰＥ原反と同様にして測定した。
また、実施例７のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。 (Example 7)
A multilayer original fabric having a three-layer structure (PP / PE / PP) was prepared using a multilayer original fabric apparatus, and was produced in the same manner as in Example 1 except that the lamination step was omitted.
Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane. The birefringence and the elastic recovery rate were measured with the raw multilayer. In addition, the elastic recovery rate was measured in the same manner as the PE original fabric.
In addition, Table 2 shows electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membrane of Example 7 was used as a separator film for an electricity storage device.
多層原反装置を使用して３層構造（ＰＰ/ＰＥ/ＰＰ）の多層原反を作製し、ラミネート工程を省略した以外は、実施例１と同様の方法で作成した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性を表１および表２に示した。複屈折および弾性回復率は多層原反のまま測定を行った。また、弾性回復率は、ＰＥ原反と同様にして測定した。
また、実施例７のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。 (Example 7)
A multilayer original fabric having a three-layer structure (PP / PE / PP) was prepared using a multilayer original fabric apparatus, and was produced in the same manner as in Example 1 except that the lamination step was omitted.
Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane. The birefringence and the elastic recovery rate were measured with the raw multilayer. In addition, the elastic recovery rate was measured in the same manner as the PE original fabric.
In addition, Table 2 shows electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membrane of Example 7 was used as a separator film for an electricity storage device.
（実施例８～実施例９）
ＰＰ原反のみを用い、ラミネート工程を省略した以外は、実施例１と同様の方法で、ＰＰ単層のポリオレフィン微多孔膜を作製した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性を表１および表２に示した。実施例８～実施例９に使用したＰＰ樹脂は表１に記載した物性の原料を使用した。
また、実施例８～実施例９のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。 (Examples 8 to 9)
A single-layer polyolefin microporous membrane was produced in the same manner as in Example 1 except that only the PP original fabric was used and the lamination step was omitted.
Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane. The PP resins used in Examples 8 to 9 used the raw materials having the physical properties described in Table 1.
In addition, Table 2 shows the electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membranes of Examples 8 to 9 were used as a separator film for an electricity storage device.
ＰＰ原反のみを用い、ラミネート工程を省略した以外は、実施例１と同様の方法で、ＰＰ単層のポリオレフィン微多孔膜を作製した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性を表１および表２に示した。実施例８～実施例９に使用したＰＰ樹脂は表１に記載した物性の原料を使用した。
また、実施例８～実施例９のポリオレフィン微多孔膜を、蓄電デバイス用セパレータフィルムとして用いた場合の電気特性（耐電圧試験の結果）を表２に示した。 (Examples 8 to 9)
A single-layer polyolefin microporous membrane was produced in the same manner as in Example 1 except that only the PP original fabric was used and the lamination step was omitted.
Tables 1 and 2 show the characteristics of the raw materials used and the properties of the obtained polyolefin microporous membrane. The PP resins used in Examples 8 to 9 used the raw materials having the physical properties described in Table 1.
In addition, Table 2 shows the electrical characteristics (results of a withstand voltage test) when the polyolefin microporous membranes of Examples 8 to 9 were used as a separator film for an electricity storage device.
（実施例１０～実施例１２）
実施例１～実施例３のポリオレフィン微多孔膜の片面に、それぞれ２μｍ、５μｍ、８μｍの耐熱多孔質層（フィラー：ベーマイト（平均粒径２μｍ））を塗工・乾燥させることで、総厚３２．０μｍ、３１．５μｍ、２９．１μｍの蓄電デバイス用セパレータフィルムを作製した。
なお、耐熱多孔質層の重量はそれぞれ、２．７２ｇ／ｍ２、６．８４ｇ／ｍ２、１０．９６ｇ／ｍ２であった。
実施例１０～実施例１２のポリオレフィン微多孔膜（実施例１～実施例３のポリオレフィン微多孔膜と同じである。）の物性を表１に示す。作製した蓄電デバイス用セパレータフィルムの物性を表２に示す。なお、実施例１０～実施例１２では、耐熱性微粒子としてフィラーであるベーマイトを用い、樹脂バインダとしてポリビニルピロリドン（ＰＶＰ）を用いてスラリーを調製し、このスラリーをポリオレフィン微多孔膜の片面に塗布して耐熱多孔質層を形成した。 (Example 10 to Example 12)
By applying and drying a heat-resistant porous layer (filler: boehmite (average particle size 2 μm)) of 2 μm, 5 μm, and 8 μm, respectively, on one side of the polyolefin microporous membranes of Examples 1 to 3, the total thickness of 32 A separator film for an electricity storage device having a thickness of 0.0 μm, 31.5 μm, and 29.1 μm was prepared.
Incidentally, each weight of the heat-resistant porous layer, 2.72g / m 2, 6.84g / m 2, was 10.96 g / m 2.
Table 1 shows the physical properties of the polyolefin microporous membranes of Examples 10 to 12 (the same as the polyolefin microporous membranes of Examples 1 to 3). Table 2 shows the physical properties of the produced separator film for an electricity storage device. In Examples 10 to 12, a slurry was prepared using boehmite as a filler as heat-resistant fine particles and polyvinyl pyrrolidone (PVP) as a resin binder, and this slurry was applied to one side of a polyolefin microporous membrane. Thus, a heat resistant porous layer was formed.
実施例１～実施例３のポリオレフィン微多孔膜の片面に、それぞれ２μｍ、５μｍ、８μｍの耐熱多孔質層（フィラー：ベーマイト（平均粒径２μｍ））を塗工・乾燥させることで、総厚３２．０μｍ、３１．５μｍ、２９．１μｍの蓄電デバイス用セパレータフィルムを作製した。
なお、耐熱多孔質層の重量はそれぞれ、２．７２ｇ／ｍ２、６．８４ｇ／ｍ２、１０．９６ｇ／ｍ２であった。
実施例１０～実施例１２のポリオレフィン微多孔膜（実施例１～実施例３のポリオレフィン微多孔膜と同じである。）の物性を表１に示す。作製した蓄電デバイス用セパレータフィルムの物性を表２に示す。なお、実施例１０～実施例１２では、耐熱性微粒子としてフィラーであるベーマイトを用い、樹脂バインダとしてポリビニルピロリドン（ＰＶＰ）を用いてスラリーを調製し、このスラリーをポリオレフィン微多孔膜の片面に塗布して耐熱多孔質層を形成した。 (Example 10 to Example 12)
By applying and drying a heat-resistant porous layer (filler: boehmite (
Incidentally, each weight of the heat-resistant porous layer, 2.72g / m 2, 6.84g / m 2, was 10.96 g / m 2.
Table 1 shows the physical properties of the polyolefin microporous membranes of Examples 10 to 12 (the same as the polyolefin microporous membranes of Examples 1 to 3). Table 2 shows the physical properties of the produced separator film for an electricity storage device. In Examples 10 to 12, a slurry was prepared using boehmite as a filler as heat-resistant fine particles and polyvinyl pyrrolidone (PVP) as a resin binder, and this slurry was applied to one side of a polyolefin microporous membrane. Thus, a heat resistant porous layer was formed.
（比較例１～比較例３）
表１に示したように、ＰＰ樹脂原料と、ＰＰ原反およびＰＥ原反の膜厚とを変更し、ＰＰ樹脂として表１に示したように、重量平均分子量が４７，００００～５１，００００、分子量分布が５．６～７．２、融点が１６６～１６７℃のＰＰ樹脂を用いた以外は、実施例１と同様にしてポリオレフィン微多孔膜を作成した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性および電気特性を表１および表２に示した。 (Comparative Examples 1 to 3)
As shown in Table 1, the PP resin raw material and the film thickness of PP raw material and PE raw material were changed, and as shown in Table 1 as PP resin, the weight average molecular weight was 47,0000 to 51,0000. A microporous polyolefin membrane was prepared in the same manner as in Example 1 except that a PP resin having a molecular weight distribution of 5.6 to 7.2 and a melting point of 166 to 167 ° C. was used.
Tables 1 and 2 show the properties of the raw materials used and the physical properties and electrical properties of the obtained polyolefin microporous membrane.
表１に示したように、ＰＰ樹脂原料と、ＰＰ原反およびＰＥ原反の膜厚とを変更し、ＰＰ樹脂として表１に示したように、重量平均分子量が４７，００００～５１，００００、分子量分布が５．６～７．２、融点が１６６～１６７℃のＰＰ樹脂を用いた以外は、実施例１と同様にしてポリオレフィン微多孔膜を作成した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性および電気特性を表１および表２に示した。 (Comparative Examples 1 to 3)
As shown in Table 1, the PP resin raw material and the film thickness of PP raw material and PE raw material were changed, and as shown in Table 1 as PP resin, the weight average molecular weight was 47,0000 to 51,0000. A microporous polyolefin membrane was prepared in the same manner as in Example 1 except that a PP resin having a molecular weight distribution of 5.6 to 7.2 and a melting point of 166 to 167 ° C. was used.
Tables 1 and 2 show the properties of the raw materials used and the physical properties and electrical properties of the obtained polyolefin microporous membrane.
（比較例４）
表１に示したように、重量平均分子量が４１０，０００、分子量分布が９．３、融点が１６４℃のＰＰ樹脂を用いた以外は、実施例８と同様にしてＰＰ単層のポリオレフィン微多孔膜を作成した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性および電気特性を表１および表２に示した。 (Comparative Example 4)
As shown in Table 1, PP single-layer polyolefin microporous material was used in the same manner as in Example 8 except that a PP resin having a weight average molecular weight of 410,000, a molecular weight distribution of 9.3, and a melting point of 164 ° C. was used. A membrane was created.
Tables 1 and 2 show the properties of the raw materials used and the physical properties and electrical properties of the obtained polyolefin microporous membrane.
表１に示したように、重量平均分子量が４１０，０００、分子量分布が９．３、融点が１６４℃のＰＰ樹脂を用いた以外は、実施例８と同様にしてＰＰ単層のポリオレフィン微多孔膜を作成した。
使用した原料の特性、および得られたポリオレフィン微多孔膜の物性および電気特性を表１および表２に示した。 (Comparative Example 4)
As shown in Table 1, PP single-layer polyolefin microporous material was used in the same manner as in Example 8 except that a PP resin having a weight average molecular weight of 410,000, a molecular weight distribution of 9.3, and a melting point of 164 ° C. was used. A membrane was created.
Tables 1 and 2 show the properties of the raw materials used and the physical properties and electrical properties of the obtained polyolefin microporous membrane.
実施例１～１２、比較例１～４において使用したＰＰ樹脂の２００℃条件によるゼロ剪断粘度を上記の方法により測定した。その結果、実施例１～１２において使用したＰＰ樹脂の２００℃条件によるゼロ剪断粘度は、１５８４９～１７７８３Ｐａ・ｓの範囲であった。これに対し、比較例１～４において使用したＰＰ樹脂の２００℃条件によるゼロ剪断粘度は、６３１０～７０７９Ｐａ・ｓの範囲であり、実施例１～１２と比較して低かった。
The zero shear viscosity of the PP resins used in Examples 1 to 12 and Comparative Examples 1 to 4 under the 200 ° C. condition was measured by the above method. As a result, the zero shear viscosity of the PP resin used in Examples 1 to 12 under the 200 ° C. condition was in the range of 15849 to 17783 Pa · s. In contrast, the zero shear viscosity of the PP resin used in Comparative Examples 1 to 4 under the 200 ° C. condition was in the range of 6310 to 7079 Pa · s, which was lower than that of Examples 1 to 12.
表２に示すように、実施例１～１２のポリオレフィン微多孔膜（または蓄電デバイス用セパレータフィルム）は、メルトダウン温度が１９５℃以上であり、耐電圧試験の結果が○であり、蓄電デバイスのセパレータとして好適であることが確認できた。
これに対し、比較例１～４のポリオレフィン微多孔膜は、メルトダウン温度が１９５℃未満であり、実施例１～１２のポリオレフィン微多孔膜と比較して、蓄電デバイスのセパレータとして用いた場合の安全性が低いものであった。 As shown in Table 2, the polyolefin microporous membranes (or separator films for power storage devices) of Examples 1 to 12 have a meltdown temperature of 195 ° C. or higher, the withstand voltage test result is ◯, It was confirmed that it was suitable as a separator.
In contrast, the polyolefin microporous membranes of Comparative Examples 1 to 4 have a meltdown temperature of less than 195 ° C., and compared with the polyolefin microporous membranes of Examples 1 to 12, when used as a separator for an electricity storage device. Safety was low.
これに対し、比較例１～４のポリオレフィン微多孔膜は、メルトダウン温度が１９５℃未満であり、実施例１～１２のポリオレフィン微多孔膜と比較して、蓄電デバイスのセパレータとして用いた場合の安全性が低いものであった。 As shown in Table 2, the polyolefin microporous membranes (or separator films for power storage devices) of Examples 1 to 12 have a meltdown temperature of 195 ° C. or higher, the withstand voltage test result is ◯, It was confirmed that it was suitable as a separator.
In contrast, the polyolefin microporous membranes of Comparative Examples 1 to 4 have a meltdown temperature of less than 195 ° C., and compared with the polyolefin microporous membranes of Examples 1 to 12, when used as a separator for an electricity storage device. Safety was low.
（実施例Ａ～実施例Ｄ、比較例５～比較例６）
表４に示すＰＰ樹脂を用いて、実施例１と同様にして、表４に示す膜厚のＰＰ原反を作成した。得られた原反は膜厚９～２６μｍであった。
得られた原反に対して、実施例１と同様にして延伸工程を行い、実施例Ａ～ＤのＰＰ単層のポリオレフィン微多孔膜を得た。 (Example A to Example D, Comparative Example 5 to Comparative Example 6)
Using the PP resin shown in Table 4, a PP original fabric having a film thickness shown in Table 4 was prepared in the same manner as in Example 1. The obtained raw fabric had a film thickness of 9 to 26 μm.
The obtained raw fabric was subjected to a stretching process in the same manner as in Example 1 to obtain PP single-layer polyolefin microporous membranes of Examples A to D.
表４に示すＰＰ樹脂を用いて、実施例１と同様にして、表４に示す膜厚のＰＰ原反を作成した。得られた原反は膜厚９～２６μｍであった。
得られた原反に対して、実施例１と同様にして延伸工程を行い、実施例Ａ～ＤのＰＰ単層のポリオレフィン微多孔膜を得た。 (Example A to Example D, Comparative Example 5 to Comparative Example 6)
Using the PP resin shown in Table 4, a PP original fabric having a film thickness shown in Table 4 was prepared in the same manner as in Example 1. The obtained raw fabric had a film thickness of 9 to 26 μm.
The obtained raw fabric was subjected to a stretching process in the same manner as in Example 1 to obtain PP single-layer polyolefin microporous membranes of Examples A to D.
実施例Ａ～実施例Ｄ、比較例５～比較例６において使用した原料の特性、および得られたポリオレフィン微多孔膜の物性および電気特性（耐電圧試験の結果）を表４に示した。
Table 4 shows the characteristics of the raw materials used in Examples A to D and Comparative Examples 5 to 6, and the physical properties and electrical characteristics (results of a withstand voltage test) of the obtained polyolefin microporous membrane.
表４に示すように、実施例Ａ～Ｄのポリオレフィン微多孔膜は、メルトダウン温度が１９５℃以上２３０℃以下であり、耐電圧試験の結果が○であり、蓄電デバイスのセパレータとして好適であることが確認できた。
これに対し、比較例５、６のポリオレフィン微多孔膜は、メルトダウン温度が１９５℃未満であり、蓄電デバイスのセパレータとして用いた場合の安全性が低いものであった。 As shown in Table 4, the polyolefin microporous membranes of Examples A to D have a meltdown temperature of 195 ° C. or more and 230 ° C. or less, and the result of the withstand voltage test is ○, which is suitable as a separator for an electricity storage device. I was able to confirm.
On the other hand, the polyolefin microporous membranes of Comparative Examples 5 and 6 had a meltdown temperature of less than 195 ° C. and had low safety when used as a separator for an electricity storage device.
これに対し、比較例５、６のポリオレフィン微多孔膜は、メルトダウン温度が１９５℃未満であり、蓄電デバイスのセパレータとして用いた場合の安全性が低いものであった。 As shown in Table 4, the polyolefin microporous membranes of Examples A to D have a meltdown temperature of 195 ° C. or more and 230 ° C. or less, and the result of the withstand voltage test is ○, which is suitable as a separator for an electricity storage device. I was able to confirm.
On the other hand, the polyolefin microporous membranes of Comparative Examples 5 and 6 had a meltdown temperature of less than 195 ° C. and had low safety when used as a separator for an electricity storage device.
実施例８、実施例Ａ～実施例Ｄ、比較例５～比較例６のポリオレフィン微多孔膜の表面開口率を上記の方法により測定した。その結果を表４に示す。また、実施例８の表面開口率は１７．７％であった。
The surface opening ratio of the polyolefin microporous membranes of Example 8, Examples A to D, and Comparative Examples 5 to 6 was measured by the above method. The results are shown in Table 4. Further, the surface opening ratio of Example 8 was 17.7%.
１ アルミ板
２ 試料
３ クリップ
１０、２０ ポリオレフィン微多孔膜
１１、２１ 空孔 1Aluminum plate 2 Sample 3 Clip 10, 20 Polyolefin microporous membrane 11, 21
２ 試料
３ クリップ
１０、２０ ポリオレフィン微多孔膜
１１、２１ 空孔 1
Claims (10)
- ポリプロピレン系樹脂を含むポリオレフィン微多孔膜であって、
メルトダウン温度が１９５℃以上２３０℃以下であることを特徴とするポリオレフィン微多孔膜。 A polyolefin microporous membrane containing a polypropylene resin,
A polyolefin microporous membrane having a meltdown temperature of 195 ° C or higher and 230 ° C or lower. - 前記ポリプロピレン系樹脂の重量平均分子量は、５０万以上８０万以下である請求項１に記載のポリオレフィン微多孔膜；
ここで、前記重量平均分子量は、ゲル浸透クロマトグラフィー（GPC）により求めたポリスチレン換算値である。 2. The polyolefin microporous membrane according to claim 1, wherein the polypropylene resin has a weight average molecular weight of 500,000 or more and 800,000 or less.
Here, the said weight average molecular weight is the polystyrene conversion value calculated | required by the gel permeation chromatography (GPC). - 前記ポリプロピレン系樹脂の分子量分布が７．５以上１６以下である請求項２に記載のポリオレフィン微多孔膜。 The polyolefin microporous membrane according to claim 2, wherein the molecular weight distribution of the polypropylene resin is 7.5 or more and 16 or less.
- 前記ポリプロピレン系樹脂の２００℃条件によるゼロ剪断粘度が、１３０００～２００００Ｐａ・ｓである請求項１～３のいずれか１項に記載のポリオレフィン微多孔膜。 The polyolefin microporous membrane according to any one of claims 1 to 3, wherein the polypropylene resin has a zero shear viscosity of 13000 to 20000 Pa · s under 200 ° C conditions.
- 更にポリエチレン系樹脂を含む請求項１～４のいずれか１項に記載のポリオレフィン微多孔膜。 The polyolefin microporous membrane according to any one of claims 1 to 4, further comprising a polyethylene resin.
- 前記ポリエチレン系樹脂を中間層とし、前記ポリプロピレン系樹脂を表層とする積層構造である請求項５に記載のポリオレフィン微多孔膜。 The polyolefin microporous membrane according to claim 5, which has a laminated structure in which the polyethylene resin is an intermediate layer and the polypropylene resin is a surface layer.
- 単位面積耐電圧が３ｋＶ／ｍ２以上である請求項１～６のいずれか１項に記載のポリオレフィン微多孔膜；
ここで、前記単位面積耐電圧は、１０ｃｍ×１００ｃｍサイズの試験片に対して電圧をかけた短絡試験において、導通しない電圧を測定することによって得られた値である。 The polyolefin microporous membrane according to any one of claims 1 to 6, wherein the unit area withstand voltage is 3 kV / m 2 or more;
Here, the unit area withstand voltage is a value obtained by measuring a non-conducting voltage in a short-circuit test in which a voltage is applied to a 10 cm × 100 cm size test piece. - 請求項１～７のいずれか１項に記載のポリオレフィン微多孔膜を有する蓄電デバイス用セパレータフィルム。 A separator film for an electricity storage device having the polyolefin microporous film according to any one of claims 1 to 7.
- 前記ポリオレフィン微多孔膜の片面または両面に耐熱多孔質層が積層され、
前記耐熱多孔質層が、耐熱性微粒子と有機バインダとを含み、
前記耐熱性微粒子の含有量が、前記耐熱多孔質層に対して８０重量％以上９９重量％以下であり、
前記耐熱多孔質層の厚さが２μｍ～１０μｍである請求項８に記載の蓄電デバイス用セパレータフィルム。 A heat-resistant porous layer is laminated on one side or both sides of the polyolefin microporous membrane,
The heat-resistant porous layer contains heat-resistant fine particles and an organic binder,
The content of the heat-resistant fine particles is 80 wt% or more and 99 wt% or less with respect to the heat-resistant porous layer,
The power storage device separator film according to claim 8, wherein the heat-resistant porous layer has a thickness of 2 袖 m to 10 袖 m. - 請求項８または９に記載の蓄電デバイス用セパレータフィルムと、正極と、負極とを備える蓄電デバイス。 An electricity storage device comprising the separator film for an electricity storage device according to claim 8 or 9, a positive electrode, and a negative electrode.
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| EP17750234.1A EP3415556B1 (en) | 2016-02-09 | 2017-02-07 | Polyolefin microporous film, separator film for power storage device, and power storage device |
| KR1020187022318A KR20180113517A (en) | 2016-02-09 | 2017-02-07 | Polyolefin microporous film, separator film for electric storage device, and electric storage device |
| US16/076,248 US11139533B2 (en) | 2016-02-09 | 2017-02-07 | Polyolefin micro-porous film, separator film for power-storage device, and power-storage device |
| CN201780007884.5A CN108473706B (en) | 2016-02-09 | 2017-02-07 | Polyolefin microporous membrane, separator for electricity storage device, and electricity storage device |
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| JP2016222366A JP6288216B2 (en) | 2016-02-09 | 2016-11-15 | Polyolefin microporous membrane, separator film for electricity storage device, and electricity storage device |
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