Laminated separator, and manufacturing method thereof

This application is filing date for 9 March 2010, application number 201080011547.1, title of invention is "laminated divider, polyolefin microporous film and divider for storage equipment" applied for of the application.

Technical Field

The present invention relates to laminated divider, polyolefin microporous membrane and separator such as for storage equipment.

Background Art

Polyolefin resin microporous membrane as a separator for battery, in particular the separating element for lithium ion battery. Lithium ion battery is used in the mobile phone, notebook type personal computer and the like in small electronic machine, but also attempt to apply it to the electric tool, a hybrid automobile, an electric automobile and the like.

All along, in the separator for lithium ion battery using polyethylene microporous membrane. The reason for this is, excellent permeability of the microporous polyethylene film, and the polymer having the 130 °C -150 ° C molten under the closure of the hole blocking the function of the electric current, so as to ensure the safety of the battery. "Obturator (shutdown)" is a microporous film of the hole is molten resin block, increase in resistance of the film, thus blocking the phenomenon of lithium ion flow.

Here, the divider, the electricity storage device is further improved from the point of view of safety, the repeated charging and discharging, in addition the rupture does not occur during the mechanical characteristics of a certain other than the above, also requires that the to stop rapidly when abnormal heating of the characteristic of the cell reaction is (fusing characteristic) or even reach high temperature also maintain the shape, prevent the positive electrode material and the negative electrode material of a direct reaction of the performance of the dangerous situation, such as (the short circuit characteristic).

The lower the temperature fuse, the higher the security effect, the holes from the form of the film are maintained after being blocked, to maintain the inter-electrode insulating point of view, when the short circuit occurs the temperature is preferably relatively high.

In recent years, in order to further improve the safety of the battery, the divider between electrode and formed with the insulating inorganic filler as a main component the method of the layer (for example, Patent document 1), in a polyethylene microporous film separator containing inorganic matter (for example, Patent literature 2, 3).

Furthermore, as part of an attempt to improve heat resistance, the high melting point of the blend of polyethylene to of polypropylene, laminated polyethylene microporous membrane to and polypropylene microporous membrane (for example with reference to Patent literature 4, 5).

Literature of the prior art

Patent literature

Patent literature 1: Japanese extra Kaiping 11-080395, the

Patent document 2: Japanese Patent section 4049416, the

Patent literature 3: Japanese opens especially 2001-266828, the

Patent literature 4: Japan opens illustriously especially 63-243146, the

Patent literature 5: Japan opens illustriously especially 62-010857, the

Content of the invention

Problem to be solved by the invention

However, heat from the high-dimensional balance, foramen obturatum characteristic and cycle performance point of view, the Patent literature 1-3 the divider are recorded in the room for improvement.

In view of the above-mentioned facts, section of the present invention 1 provide high dimension heat balance, and foramen obturatum characteristic divider cycle characteristics.

Furthermore, after repeated charging and discharging from the well to maintain battery capacity after the characteristics of the point of view of (circulating property), Patent document 4, 5 the porous membrane are recorded in the room for improvement.

In view of the above-mentioned facts, paragraph of this invention 2 object is to provide suitable as a storage device can improve the cycle characteristics of the polyolefin microporous membrane of the separator.

The programme applied to the solution of the problem

The present inventors in view of the above fact in the in-depth research, found, containing the particle size of the inorganic particles of a specific range and has a laminated structure of high dimension laminated divider can heat balance, foramen obturatum characteristic and cycle performance.

Another discovery, with a specific composition is polypropylene polyolefin microporous film can solve the above-mentioned section 2 issues.

And, through the compounding polypropylene microporous film in a specific amount of specific propylene copolymer, can solve the above-mentioned section 2 issues.

Furthermore, by containing the inorganic filling material of polypropylene microporous film in a specific amount of a specific acrylic copolymer compounded, can solve the above-mentioned section 2 issues, and then end the invention.

In other words, the invention are described below.

[1] a cascade divider, its having a polyolefin article 1 micro porous level and laminated on the section 1 and the porous layer 1 microporous layers of different polyolefin section 2 micro porous level , the section 1 with the micro porous level section 2 micro porous level containing at least one of a primary particle size of 1 nm or more and 80 nm the following inorganic particles.

[2] the above-mentioned the laminated divider, the polyolefin section 1 micro porous level of the polyolefin resin and the inorganic particles in the total concentration of inorganic particles C1 with the polyolefin section 2 micro porous level of the polyolefin resin and the inorganic particles in the total concentration of inorganic particles C2 the difference is 10 mass % or more and 95% of the following quality.

[3] the above-mentioned or the laminated divider, wherein the inorganic particles are selected from the group consisting of silicon oxide, aluminum oxide and titanium oxide of 1 or 2 or more kinds.

[4] the above-mentioned-[ 3] to any one of the laminated divider, it has the polyolefin section 1 the surface layer micro porous level , the polyolefin section 2 micro porous level as an intermediate layer of at least 2 kinds of 3 layer structure,

And, the polyolefin section 1 contains micro porous level relative to the section 1 micro porous level a component of the polyolefin resin and the inorganic particles to the total amount of 5-90 quality % of the polyolefin resin, the polyolefin section 2 contains micro porous level relative to the section 2 of the components constituting the micro porous level polyolefin resin and of the total amount of inorganic particles 60-100 quality % of the polyolefin resin.

[5] the above-mentioned the laminated divider, wherein the superficial layer, the polyolefin resin comprises polyethylene and polypropylene, the polypropylene in the polyethylene and polypropylene of the proportion of the total amount of the in 10 mass % or more and 95% of the following quality.

[6] a polyolefin microporous film, in order to contain the same 50-99 quality % polypropylene, 1-50 quality % propylene-α-olefin copolymer of a polyolefin resin as a main component to form,

The propylene-α-olefin copolymer, the α-olefin content of more than 1 mass % and 15% of the following quality.

[7] the above-mentioned the polyolefin microporous film, wherein said propylene with the propylene-α-olefin copolymer than of compounding, that is, (polypropylene/propylene-α-olefin copolymer) (mass ratio) is 1.5 or more and 60 the following.

[8] the above-mentioned or the polyolefin microporous film, wherein the polyolefin resin further comprises high-density polyethylene, the high-density polyethylene in the polyolefin resin in the proportion of 5-45 quality %.

[9] the above-mentioned-[ 8] to any one of the polyolefin microporous film, containing the same inorganic filling material, and the inorganic filling material in the inorganic filling material and the total amount of the polyolefin resin in the proportion of 1-80 quality.

[10] the above-mentioned the polyolefin microporous film, wherein the inorganic filling material is selected from silicon dioxide, aluminum oxide and titanium oxide in any of the group consisting of 1 or more.

[11] a kind of multilayer polyolefin microporous membrane, the in-[ 10] to any one of the polyolefin microporous membrane is laminated on at least one side with the polyolefin microporous film of different other polyolefin microporous membrane.

[12] a storage device divider, which consists of a-[ 10] to any one of the polyolefin microporous film or the laminated polyolefin microporous film.

[13] a polyolefin microporous membrane, characterized in that it is made up of propylene resin composition forming, states the propylene series resin composition containing the (polypropylene) / (propylene copolymer) (mass ratio) is 80/20 to 0/100 polypropylene resin as a main component,

The melting point of the propylene copolymer is 120 °C more than and 145 °C the following.

[14] the above-mentioned the polyolefin microporous film, characterized in that the propylene copolymer is a random copolymer.

[15] the above-mentioned or the polyolefin microporous film, characterized in that the propylene copolymer containing in the comonomer content is more than 1 mass % and 20% of the following quality.

[16] the above-mentioned-[ 15] to any one of the polyolefin microporous film, wherein the propylene resin composition also contains high-density polyethylene, and the high-density polyethylene in the propylene resin composition in the proportion of 5-50 quality %.

[17] the above-mentioned-[ 16] to any one of the polyolefin microporous film, characterized in that the propylene resin composition also contains an inorganic filling material, and the inorganic filling material in the propylene resin composition in the proportion of 5-60 quality %.

[18] a kind of multilayer polyolefin microporous membrane, the in-[ 17] according to any one of the polyolefin microporous membrane is laminated on at least one side with the polyolefin microporous film of different other polyolefin microporous membrane.

[19] a separator for non-aqueous electrolyte solution, which consists of a-[ 17] according to any one the polyolefin microporous film or the laminated polyolefin microporous film.

[20] a-[ 17] a in the polyolefin microporous film or the method of manufacturing laminated microporous polyolefin film, characterized in that with the following process:

(1) according to the required layer, containing the (polypropylene) / (propylene copolymer) (mass ratio) is 80/20 to 0/100 polypropylene resin as a main component and a plasticizer propylene resin composition according to need and high-density polyethylene, of inorganic filling material mixing, a mixing process of reading,

(2) after the mixing process, according to the required layer form, each layer of the raw material will be extruded into sheet, according to the needs of the after the lamination is cooled and solidified, is processed into a sheet-shaped molded body (single-layer molded product or are stacked in a body) of the sheet forming process,

(3) after the shaping process, the surface ratio of 20 times or more and 200 times the following to the flaky molded article is subjected to biaxial stretching, the stretching process forming inhibitor,

(4) after the stretching process, extracting plasticizer from the stretched, porous body forming step of forming a porous body,

(5) in the porous body after the forming process, the below the melting point of the polyolefin resin to the porous body is subjected to heat treatment, stretching in the width direction of the heat treatment process.

[21] the above-mentioned, the manufacturing method, characterized in that the propylene copolymer is the heat of fusion of the 60J/g the above.

[22] a polyolefin microporous film, which consists of a polypropylene resin composition, the propylene resin composition containing (polypropylene) / (propylene copolymer) (mass ratio) is 90/10 to 0/100 polypropylene resin 20-95 quality and % inorganic filling material 5-80 mass %,

The melting point of the propylene copolymer is 110 °C -150 °C, propylene copolymers with inorganic filling material mass ratio is 0.1/1-1.5/1.

[23] the above-mentioned the polyolefin microporous film, characterized in that the propylene copolymer is a random copolymer.

[24] the above-mentioned or the polyolefin microporous film, characterized in that the propylene copolymer containing in the comonomer content is more than 1 mass % and 20% of the following quality.

[25] the above-mentioned-[ 24] to any one of the polyolefin microporous film, characterized in that the propylene resin composition also contains high-density polyethylene, and the high-density polyethylene in the propylene resin composition in the proportion of 5-60 quality %.

[26] the above-mentioned-[ 25] according to any one of the polyolefin microporous film, characterized in that the inorganic filling material is silicon dioxide, aluminum oxide or any of the titanium.

[27] a kind of multilayer polyolefin microporous membrane, its in the above-mentioned-[ 26] to any one of the polyolefin microporous membrane is laminated on at least one side with the polyolefin microporous film of different other polyolefin microporous membrane.

[28] a separator for non-aqueous electrolyte solution, which is composed of the above-mentioned-[ 26] to any one of the polyolefin microporous film or the laminated polyolefin microporous film.

[29] a-[ 26] to any one the polyolefin microporous film or the method of manufacturing laminated microporous polyolefin film, characterized in that its with the following process:

(1) according to the required layer, containing the (polypropylene) / (propylene copolymer) (mass ratio) is 90/10 to 0/100 polypropylene resin 20-95 quality and % inorganic filling material 5-80 mass % of the polypropylene resin composition according to need and plasticizer and mixing the high-density polyethylene, the process of milling to form a reading;

(2) after the mixing process, according to the required layer form, each layer of the raw material will be extruded into sheet, according to the requirements the laminate is cooled and solidified, is processed into a sheet-shaped molded body (single-layer molded product or are stacked in a body) of the sheet forming process;

(3) after the shaping process, the surface ratio of 20 times or more and 200 times the following to the flaky molded article is subjected to biaxial stretching, the stretching process forming inhibitor;

(4) after the stretching process, extracting plasticizer from the stretched, porous body forming step of forming a porous body;

(5) in the porous body after the forming process, the below the melting point of the polyolefin resin to the porous body is subjected to heat treatment, stretching in the width direction of the heat treatment process.

[30] the above-mentioned, the manufacturing method, characterized in that the propylene copolymer is the heat of fusion of the 60J/g the above.

Effect of the invention

The present invention provides heat balance high dimension , and foramen obturatum characteristic divider cycle characteristics.

Furthermore, the invention also provides as can improve the cycle characteristics of the storage equipment of the divider preferably the polyolefin microporous film.

Description of drawings

Figure 1 of the embodiment of said use of the obturator temperature measuring device compend Figure.

Note the Figure mark

1: microporous membrane

2A, 2B: thickness 10 µm the nickel foil

3A, 3B: glass plate

4: electric resistance-measuring apparatus

5: thermocouple

6: thermometer

7: data collector

8: oven

Mode of execution

The following detailed description of the mode for carrying out the invention (the following atom as "the embodiment". ). To note, the invention is not limited to the following embodiment, the thrust of which can be within the range of all kinds of them.

[Section 1 embodiment]

Section of the invention 1 embodiment (the following atom to "this embodiment the 1 [...]) laminated divider having a polyolefin article 1 micro porous level (the following also referred to as" subsection 1 micro porous level ") and laminated on the section 1 and the porous layer 1 microporous layers of different polyolefin section 2 micro porous level (the following also referred to as" subsection 2 micro porous level "), the section 1 micro porous level and the section 2 micro porous level containing at least one of a primary particle size of 1 nm or more and 80 nm the following inorganic particles (sometimes also record as the" inorganic filling material ").

The embodiment 1 of the inorganic particles used in the primary particle size of 1 nm or more and 80 nm the following. For the above-mentioned particle size of the inorganic particles can be within the range of to disperse the polyolefin in good, so that good integration with the polyolefin, can greatly improve the divider has the three-dimensional mesh skeleton structure of the melt tension of the small fiber portion.

On the other hand, this embodiment is 1 stacked separating member has a laminated structure, each layer is formed in a different state, so that between the various layers, pore structure, melting behavior, the dispersed state of the inorganic particles having different. Moreover, by using a the above-mentioned specific range of particle size of the inorganic particles and laminated structure of, the heat resistance in a high dimension, and foramen obturatum characteristic unexpected effect of cycle characteristics.

Although the role of not clear in detail, but the view that the above molten acts between the layers of the existence of such differences (the presence of the interface) can help to improve the heat resistance of the whole as a spacer, at the same time having a specific range with the use of a synergistic effect of particle size of the inorganic particles, the pore structure of the each layer is moderately uniform, respectively, contribute to improving the wettability of the electrolyte, improve the cycle characteristics, and further contribute to improve the closed cell characteristic.

Here, the polyolefin section 1 section with the polyolefin micro porous level 2 microporous layer although different, but here the "different" can be as different of raw materials, can also be used as the structure of the different (i.e., porosity, such as different porous structure).

As the polyolefin section 1 section or polyolefin micro porous level 2 micro porous level use in the polyolefin resin can be cited, for example, ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene, and the like obtained by the polymerization of monomers of a polymer (homopolymer or copolymer, such as multi-stage polymer). These polymers can be use singly 1 and or 2 or more kinds.

Furthermore, as the polyolefin resin, for example polyethylene can be cited (, for example, low-density polyethylene, linear low density polyethylene, medium density polyethylene, high-density polyethylene (density: 0.942g/cm³ the above), ultra-high molecular weight polyethylene), polypropylene (e.g., isotactic polypropylene, atactic polypropylene), polybutene, ethylene-propylene-diene rubber, propylene-ethylene copolymer, propylene-α-olefin copolymer or the like. For the propylene-ethylene copolymer, propylene-α-olefin copolymer speaking, ethylene and α-olefin in the position of the polymer chain is not particularly limited, can use the random copolymer, block copolymer of any one of the. To note, the following sometimes the polyethylene particle is "PE", polypropylene "PP" for the particle.

The polyolefin resin preferably having a viscosity average molecular weight of 5 million or more, more preferably to 10 million or more, as the upper limit is preferably 1000 million the following, more preferably 300 million the following. Preferably make the viscosity average molecular weight of 5 million to the above reasons is that, when the can increase the melt tension of the melt formed, can be expected to improve the formability, and can be expected to be fully among the molecules of the complex, the tendency of a turn into high strength. From the to apply a uniform molten mixing point of view of improving the formability of the sheet material and, in particular, the thickness of the point of view of stability, preferably make the viscosity average molecular weight is 1000 million the following. In particular, from the viewpoint of further improving the formability, preferably make the viscosity average molecular weight is 300 million the following.

Closed from the reduced temperature, improving the point of view of stability, the can also contain polyolefin resin having a viscosity average molecular weight is preferably 800 or more, more preferably 900 or more, further preferably 1000 or more, as the upper limit is preferably 1 million the following low molecular weight resin.

As a low molecular weight resin, can cite polyethylene, polypropylene, polybutene, ethylene-propylene copolymer (containing an elastomer), and the like, however, from a membranaceous to make or make it a perspective of the closed hole, more preferably polyethylene, polypropylene.

To note, the low-molecular-weight resin in the polyolefin resin is preferably in the proportion of 0.1 mass % or more, more preferably 0.5 mass % or more, further preferably 1 mass % or more, as the upper limit is preferably 20 mass % or less, more preferably 15 mass % or less, further preferably 10 mass % the following.

To note, in the latter in a layer of inorganic particles, from a perspective of the dispersed inorganic particles, as PE, preferably separate the use sticks average molecular weight of 20 million the above-mentioned 300 million the following of a high density polyethylene or a viscosity average molecular weight is 100 million or more ultra-high molecular weight polyethylene or the combination of the two.

As the inorganic particles, for example, can be cited

(1) silicon, aluminum, titanium oxide or nitride of the elements,

(2) calcium, barium carbonate or sulfate of the elements.

Balance from high-dimension the heat resistance of the separator and circulating the characteristic point of view, preferably using the above-mentioned (1) or (2) the inorganic particle.

This kind of inorganic particles are preferably in the presence of dispersed separately in micro porous level , there may be also part of agglutination.

As particle size of the inorganic particles, the lower limit is preferably 1 nm or more, more preferably 6 nm or more, further preferably 10 nm or more, the upper limit is preferably 80 nm or less, more preferably 50 nm or less, further preferably 30 nm the following.

The resin composition containing said polyolefin resin (the following also referred to as "polyolefin composition". ) Can be incorporated in various additives according to the need. As this kind of additive, for example can be cited a phenol-based antioxidant, phosphoric acid series, sulfur series antioxidants, etc., nucleating agent, calcium stearate, zinc stearate and other metal soap, ultraviolet absorber, light stabilizer, antistatic agent, against dizzy medicinal preparation , coloring pigment, and the like.

This kind of additive in the polyolefin composition in a proportion of preferably 5 mass % or less, more preferably 2 mass % the following, can be substantially 0% quality.

As the polyolefin section 1 micro porous level of the polyolefin resin and the inorganic particles in the total concentration of inorganic particles C1 with the polyolefin section 2 micro porous level of the polyolefin resin and the inorganic particles in the total concentration of inorganic particles C2 the concentration difference, preferably 10 mass % or more, more preferably 20 mass % or more, further preferably 40 mass % or more, especially preferably 60 mass % or more. As the upper limit is preferably 95 mass % or less, more preferably 80% of the following quality. From improved heat resistance, the point of view of cycle characteristics, the concentration difference is preferably 10 mass % or more. From the closed cell characteristic, puncture strength point of view, is preferably 95 mass % the following.

To note, the embodiment 1 in "inorganic particle concentration" refers to inorganic particles in the polyolefin resin and the inorganic particles in the proportion of the total amount.

Furthermore, the inorganic filling material in the polyolefin section 1 in the porous layer with the volume proportion of the inorganic filler material in the polyolefin section 2 in the porous layer of the difference between the volume ratio is preferably 10% or more the volume, more preferably to 15 volume % or more, further preferably 20% more than the volume, especially preferably 60 volume % or more. The upper limit is preferably 95% of the following volume, more preferably 80% of the volume.

The following, in order to have the polyolefin section 1 the surface layer micro porous level , the polyolefin section 2 for micro porous level 2 types 3 in the layer structure of the embodiment as to the mode of execution of the center 1 to explain a laminated spacer.

To form the surface layer section 1 micro porous level polyolefin resin concentration is preferably 5-90 mass %, more preferably 20-80 quality %.

Here, as to form a surface layer of the polyolefin resin preferably contains PE and PP. The PE and PP PP in the proportion of the total amount is preferably 10 mass % or more, more preferably 20 mass % or more, further preferably 40 mass % or more, preferably 95% of the following quality, more preferably 90% of the following quality, further preferably 80 mass % the following.

From the obtained and good heat-resistance point of view of improving the stretchability, high puncture strength of the obtained porous film point of view, this kind of surface layer is preferably formed.

To note, the embodiment 1 in, "polyolefin resin concentration" refers to polyolefin resin the polyolefin resin and the inorganic particles in the proportion of the total amount.

As the surface layer of the said C1, preferably 10 mass % or more, more preferably 20 mass % or more, further preferably 40 mass % or more, especially preferably 60 mass % or more, as the upper limit is preferably 95 mass % or less, more preferably 90% of the following quality, more preferably 80% of the following quality. From improved heat resistance, the point of view of cycle characteristics, preferably so that the proportion is 10 mass % or more. On the other hand, under high stretching ratio from improving the film forming property, of increasing polyolefin resin micro-porous film puncture strength point of view, is preferably 95 mass % the following. A polyolefin resin and from further improve the interaction of the inorganic particles, and then high-dimension can give consideration to the heat resistance of the laminated spacers and circulating the characteristic point of view, preferably in the surface layer of the inorganic particles used in combination, and PE PP, and the proportion of each ingredient is set to the above-mentioned range.

Furthermore, the inorganic filling material in the polyolefin section 1 in the porous layer is preferably the volume proportion of 10 volume % or more, more preferably 15% volume, more preferably 20% more than the volume of, the upper limit is preferably 95% volume.

As forming the section of the middle layer 2 polyolefin resin concentration micro porous level , preferably 60 mass % or more, more preferably 80 mass % or more, more preferably 90% or more the quality, can also be a 100% quality.

Furthermore, as the intermediate layer in the polyolefin resin preferably in the PE as the main component, can also be closed without damage and within the range of characteristic PP. Intermediate layer, PE and PE PP as in for the proportion of the total amount is preferably 60 mass % or more, more preferably 80 mass % or more, can also be a 100% quality.

As the intermediate layer of the C2, preferably 60 mass % or less, more preferably 40% of the following quality, more preferably 20 mass % or less, further preferably 10 mass % the following, can also be 0% quality. From the point of view of closed cell characteristic, preferably so that the proportion is 60% of the following quality.

Furthermore, as the inorganic filling material accounts for the polyolefin section 2 in the porous layer is preferably the volume proportion of 60 the following % volume, more preferably 40% of the volume, more preferably 20% of the following volume, further preferably 10% volume the following, can also be a 0 volume %.

Furthermore, as the proportion of the inorganic filling material is preferably 1.0g/cm³ more, more preferably 1.2g/cm³ more, more preferably 1.5g/cm³ the above, the upper limit is preferably 10.0g/cm³ the following.

Heat resistance and foramen obturatum characteristic from, the point of view of cycle characteristics, preferably has the section 1 the surface layer micro porous level , the section 2 of the intermediate layer to micro porous level 2 types of 3 layers, and that the section 1 containing a polyolefin resin and microporous layer of inorganic particles, the section 2 microporous layer does not include the composition of the inorganic particles.

On the other hand, and circulating the characteristic from foramen obturatum characteristic the productivity of the battery and the point of view of manufacture, preferably has the section 2 the surface layer micro porous level , the section 1 of the intermediate layer to micro porous level 2 type 3 form, and the section 1 containing a polyolefin resin and microporous layer of inorganic particles, the section 2 microporous layer does not include the composition of the inorganic particles.

As the embodiment 1 of the method for manufacturing laminated spacers no special limit, can be cited, for example, contains the following (1)-(4) the method for manufacturing of the process:

(1) for forming each layer of the raw material (polyolefin composition and plasticizer) are respectively melt mixing process,

(2) in the process (1) the rear, will conduct molten milling of reading obtained by co-extrusion, lamination of the cambium material and the process of cooling and solidifying,

(3) in the process (2) then, in at least a uniaxial direction at 20 times or more and less than 200 times magnification to stretch the surface of the process,

(4) in the process (3) before or after the step of extracting the plasticizer.

As the process (1) of the plasticizer used in, preferably in compounding with the polyolefin resin the polyolefin resin a temperature above the melting point of the molten resin forming a non-volatile solvent, preferably at room temperature the liquid. As plasticizer, can be cited, for example, liquid paraffin, paraffin hydrocarbon, dioctyl phthalate, dibutyl phthalate and other esters, oleyl alcohol, stearyl alcohol, higher alcohol, and the like.

As a plasticizer, the proportion of compounding with the polyolefin composition, preferably can be a melting, mixing, for forming sheet-like microporous membrane precursor fully and does not damage the ratio of the level of productivity. Specifically, the polyolefin as a plasticizer in the composition and plasticizer content of the total amount of the (plasticized dosage ratio) is preferably 20 mass % or more and 80 mass % or less, more preferably 30% or more the quality of 70% of the following quality. When the melt formed from the height of the melt tension, ensure that the point of view of formability, the content of the plasticizer is preferably 80% of the following quality. From the point of view of formability, and to ensure efficient stretched polyolefin resin of the crystalline area of the lamella in perspective, the content of the plasticizer is preferably 20 mass % or more. Here, high-efficient stretched platelet means that the polyolefin does not occur under the condition of rupture resin chain expandering polyolefin resin chain high-efficiently, and can contribute to the formation of a uniform fine pore structure, improve the strength of the porous film.

Polyolefin composition and plasticizer as the melt mixing method, it is preferred to use a plurality of the extruder, in a polyolefin resin and the inorganic particles according to the needs and the kind of additive, the polyolefin composition is heated molten on one side in order to introduce arbitrary ratio of plasticizer, and then mixing the composition, so as to obtain homogeneous method of the molten resin. As the polyolefin resin and the inorganic particles and the plasticizer to melt mixing method for more preferably, can be cited the mixer through henschell polyolefin resin and inorganic particles and plasticizer prior mixing to the required proportion of the process, the input to the extruder method, the arbitrary ratio on one side in order to heating and melting into the plasticizer, further mixing.

As the process (2) in the method of co-extrusion, preferably using a die of the extruder from a plurality of melt extruded in mold cementation , it is preferred to use a multi- manifold law , to material law (feedblockmethod). Here, it is preferred to use a T-die, flat die head such as hanger shaped die head.

Furthermore, the process (2) preferably by cooling and solidifying of the sheet are formed to be in contact with the heat conductor, cooling to fully lower than the temperature of the crystallization temperature of the resin to such methods.

Process (3) in, at least a corresponding uniaxial tensile direction of stretching. A double-shaft direction when a high-magnification, because the direction of the molecular orientation on the surface, making it difficult to crack, become stable structure, there was the tendency of high puncture strength, therefore, preferred. Stretching method also can be used independently or and at the same time for the biaxial stretching, successive biaxial stretching, multi-stage stretching, a plurality of times as a method for stretching, and the like, from the puncture strength of the film thickness or increase a perspective, a particularly preferred method of stretching is simultaneous biaxial stretching.

With MD of the TD than the stretching ratio is preferably 0.5 or more 2 the following. Furthermore, stretching ratio dynameter with the surface is preferably 20 times or more and less than 200 times, more preferably 20 times more than 100 times the following range, further preferably 25 times more than 50 times the scope of the following. The total area ratio of 20 times the above, to a film exists the tendency to fully puncture strength, less than 200 times, preventing the membrane breakage, the tendency of obtaining high productivity, thereby preferably.

To illustrate, refer to "MD" when system membrane longitudinal direction or of the separator ejecting direction of the raw material resin, refer to "TD" in the width direction of the separator.

Stretching temperature is preferably (melting point -50 ° C of polyolefin) or more, is less than the melting point. More preferably (melting point -30 ° C of polyolefin) or more, and the (melting point -2 ° C of polyolefin) the following, preferably further (melting point -15 ° C of polyolefin) or more, and the (melting point -3 ° C of polyolefin) the following. From the point of view of high puncture strength, preferably make the stretching temperature is (the melting point -50 ° C polyolefin) or more. Stretching is not of the perspective, preferably less than the melting point of the polyolefin.

Process (4) may be batchwise, continuous any one of the, by preferably making the laminated sheet material in impregnated in extraction solvent for extracting plasticizer, and make its full drying, in the plasticizer from the microporous film is substantially removed. In order to inhibit contraction of the laminated sheet material, preferably of the immersion, drying in a series of process of the end part of the restraint layer sheet material. Furthermore, in the laminated sheet material after extracting the plasticizer residual stock preferably less than 1 mass %. When containing additive, additive is preferably selected in the plasticizer in the process of extracting the plasticizer is extracted together, as a film of the residual stock preferably in a substantially 0%.

Extraction solvent preferably to polyolefin resin, inorganic particles as the poor solvent, and the plasticizer is a good solvent, boiling point lower than the melting point of the polyolefin resin. As this extraction solvent, n-hexane can be cited, for example, hydrocarbons such as cyclohexane, dichloromethane, 1, 1, 1-trichloroethane and other halogenated hydrocarbons, hydrofluoroether, hydrofluorocarbons above chlorine-free halide solvent, such as, ethanol, isopropanol alcohol, diethyl ether, tetrahydrofuran, ether, acetone, methyl ethyl ketone, ketone.

Furthermore, preferably to heat-fixing, heat treatment process, such as thermal relaxation, thereby having the further inhibit contraction of the stratify the tendency of separating member.

And, also can be post-processing procedure. As a post-processing procedure, for example by using surface active agents and the like can be cited of ionization radiation and processing hydrophilization of the cross-linking treatment, and the like.

In the embodiment 1 the case of a laminated spacer, as the overall film thickness is preferably 2 µm more, more preferably 5 µm more, preferably 30 µm the following, more preferably 25 µm the following, more preferably 20 µm the following. From the point of view of improving the mechanical strength, preferably make the overall film thickness is 2 µm the above. On the other hand, preferably, the total film thickness is 30 µm the following, the reason for this is to reduce the volume a of the separator, from the battery the point of view of the high capacity, the tendency of a becomes favorable.

The lower limit of the film thickness of the surface layer is preferably 0.5 µm more, more preferably 1 µm more, more preferably 2 µm the above, as the upper limit is preferably 15 µm the following, more preferably 10 µm the following, more preferably 5 µm the following. From the viewpoint of heat resistance, preferably make the surface layer of the film thickness is 0.5 µm the above. On the other hand, from the viewpoint of improving the mechanical strength, the film thickness is preferably make the surface layer 15 µm the following.

The porosity of the laminated spacers is preferably 40% or more, more preferably 50% or more, preferably 90% or less, more preferably 80% of the following. From the point of view of the battery characteristics, preferably make the porosity is 40% or more. From the point of view of ensuring that the puncture strength, the porosity is preferably 90% the following.

Air permeability of the laminated spacers is preferably 10 seconds/100cc more, more preferably 50 seconds/100cc more, preferably 1000 seconds/100cc the following, more preferably 500 seconds/100cc the following, more preferably 300 seconds/100cc the following. Inhibiting the self-discharge of the battery from the point of view of the air permeability preferably make the 10 seconds/100cc the above. On the other hand, to charge and discharge characteristics from the point of view of good, preferably make the air permeability of 1000 seconds/100cc the following.

Laminated divider puncture strength is preferably more than 3.0N/20 µm, more preferably more than 4N/20 µm, preferably 10N/20 µm the following, more preferably 7N/20 µm the following. When winding from inhibiting the battery the falling off of the active material to the point of view of the rupture of the membrane, preferably make the puncture strength is more than 3.0N/20 µm. On the other hand, from the point of view of reducing thermal contraction, preferably make the puncture strength is 10N/20 µm the following.

Indicators foramen obturatum characteristic lamination of the separator as a closed cell temperature is preferably 150 °C the following, more preferably 145 °C the following, more preferably 140 °C the following. From the point of view of ensuring the safety of the battery, preferably make the closed-cell temperature is 150 °C the following.

As the laminated spacer (soldertest) heat resistance in soldering of indicators of measurements of the test, the 300 °C is preferably under 5.0 mm² the following, more preferably 4.0 mm² the following, in the 400 °C is preferably under 8.0 mm² the following, more preferably 7.0 mm² the following. From the heat resistance, of forming a microporous membrane a hole the viewpoint of structure, preferably make the brazing test in the measured value of 300 °C to 5.0 mm² the following, 400 °C to 8.0 mm² the following.

The cycle characteristics of the laminate as the separator capacity maintaining rate is preferably 80% or more, more preferably 85% or more. From the point of view of service life of the battery, preferably make the capacity maintenance ratio is 80% or more.

This embodiment is 1 laminated divider as a battery, in particular, divider useful for lithium ion battery. The use of the stacked spacers of the cycle characteristics of the battery obtained, excellent safety, thus be used as a mobile phone, notebook nature personal computer, an electric tool, a hybrid automobile, useful for electric automobile.

[Section 2 embodiment]

Paragraph of this invention 2 embodiment (the following atom to " this embodiment the 2 [...]) containing polyolefin microporous membrane of polypropylene 50-99 quality %, propylene-α-olefin copolymer 1-50 quality % of the polyolefin resin as a main component to form,

The propylene-α-olefin copolymer, the α-olefin content of more than 1 mass % and 15% of the following quality.

Here, in the embodiment 2, can be realized by adopting the above-mentioned a good cycle characteristics for storage equipment detailed reasons are not of the separator, but that said as follows.

In other words, the embodiment 2 in the compounding polypropylene and propylene-α-olefin copolymer, however, supposed the propylene-α-olefin copolymer with the α-olefin part of the role of crystallization degree the polypropylene. That here, when the states the propylene -α-olefin copolymer contains a specific amount of α-olefin part, the α-olefin part properly act on the polypropylene part, formed in the sheet of the polypropylene part adjusted to the appropriate thickness. And, when the generation of the plurality of the sheet of the appropriate thickness, the formation of microporous membrane are generated when a plurality of the small hole. When the this kind has a large plurality of equalizer eyelet department of the porous membrane is disposed on the interior of the battery, ions are not no thick dense through the flow path, there is the, charge and discharge repeatedly when the blockage is not easy to occur, improving the cycle characteristics of the battery.

As the polypropylene, for example can be cited of isotactic polypropylene, atactic polypropylene. These polypropylene can use 1 or a mix of 2 or more kinds.

Furthermore, polypropylene in the polyolefin resin in the proportion of 50 mass % or more, preferably 60 mass % or more, more preferably 70 mass % or more, as the upper limit is 99% of the following quality.

On the other hand, the propylene-α-olefin copolymer (sometimes only record as the "propylene copolymer". ) Used as the monomer propylene and as the different monomer propylene α-olefin formed.

As this kind of α-olefin, can be cited, for example, ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene, and the like. To note, for the propylene-α-olefin copolymer speaking, the polymer chain α-olefins is no particular limitation to the position of the, can also use random copolymer, block copolymer of any one of the.

The propylene-α-olefin copolymer, the α-olefin content of more than 1 mass % and 15% of the following quality, is preferably 2 mass % or more and 10 mass % the following. The content of more than 1% can contribute to the quality of the improvement of the battery properties. On the other hand, the resulting microporous membrane from improving heat resistance, improve the point of view of safety of the battery, preferably 15% of the following quality.

Furthermore, propylene-α-olefin copolymer in the polyolefin resin in the proportion of 1 mass % or more, more preferably 3 mass % or more, more preferably 5 mass % or more, as a limit of 50% of the following quality.

To note, the polyolefin resin in addition to the above-mentioned polypropylene propylene-α-olefin copolymer outside, can also be mixed with other resin component.

As the other resin component, can be cited, for example, ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene, and the like of the obtained monomer with polymer (homopolymer or copolymer, such as multi-stage polymer). These polymers can be used independently 1 or can be simultaneously used for 2 or more. But does not include polypropylene and propylene-α-olefin copolymer.

Furthermore, as the other resin component, may, for example, be cited polyethylene {low density polyethylene (910 kg/m³ or more, less than 930 kg/m³), linear low density polyethylene, medium density polyethylene (930 kg/m³ or more, less than 942 kg/m³), high density polyethylene (942 kg/m³ the above), ultra-high molecular weight polyethylene}, polybutene and the like.

As the polyolefin resin, the polyolefin microporous membrane from the puncture strength point of view, preferably containing a high-density polyethylene.

High-density polyethylene in the proportion of the polyolefin resin can be 0% quality, is preferably 5 mass % or more, more preferably 10 mass % or more, preferably 45% of the following quality. From improved heat resistance, improve battery safety point of view, preferably the proportion of the high-density polyethylene to 45% of the following quality.

As the above-mentioned various polyolefin composition having a viscosity average molecular weight of (when using a plurality of polyolefin component, each refer to the determination of the value of the polyolefin component. ) Is preferably 10 million or more, more preferably 12 million or more, as the upper limit is preferably 1000 million the following, more preferably 300 million the following. When the melt formed from the height of the melt tension, to ensure good formability or to the views of the full complex, improve the point of view of strength of the porous film, preferably the viscosity average molecular weight is 10 million or more. On the other hand, a from the melt mixing, the formability of the sheet material, in particular the thickness of the point of view of stability, preferably make the viscosity average molecular weight is 1000 million the following. From the point of view of further improving the formability, preferably make the viscosity average molecular weight is 300 million the following.

The polyolefin resin can be cited in the above-mentioned the embodiment 1 is the same as the example in the material. Furthermore, with this embodiment the amount of 1 the same.

This embodiment is 2 containing polyolefin microporous membrane of polypropylene and propylene-α-olefin copolymer of a polyolefin resin as a main component. Here, the "main component" refers to polyolefin resin the polyolefin microporous film the proportion of in is preferably 20 mass % or more, more preferably 30 mass % or more, further preferably 50 mass % or more, more preferably 70 mass % or more, especially preferably 90% or more the quality, can also be 100% quality.

The polypropylene with the propylene-α-olefin copolymer for matches mixes the ratio (polypropylene/propylene-α-olefin copolymer) (mass ratio) is preferably 1.5 or more 60 the following, more preferably 2 or more 55 the following. From the point of view of improving battery characteristics, preferably the compounding ratio of 60 the following, from improved heat resistance, improve battery safety point of view, is preferably 1.5 or more.

The embodiment 2 of the polyolefin microporous film can also contain inorganic filling material.

As this kind of inorganic filling material, for example, can be cited alumina, silica (silicon oxide), titanium oxide, zirconium dioxide, magnesium oxide, cerium oxide, yttrium oxide, zinc oxide, iron oxide and other oxide ceramic, silicon nitride, titanium nitride, boron nitride, nitride ceramic, silicon carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, clay, kaolinite, multiple water kaolinite, pyrophyllite, montmorillonite, sericite, mica, amesite , bentonite, asbestos, zeolite, calcium silicate, magnesium silicate, diatomaceous earth, silica sand, ceramic, glass fiber and the like. These substances can be used independently 1 or can be the combination of 2 or more kinds. Wherein from the viewpoint of electrochemical stability, more preferably silicon dioxide, aluminum oxide, titanium oxide, silicon dioxide is particularly preferred.

As the inorganic filling material, the average particle size, preferably 1 nm or more, more preferably 6 nm or more, further preferably 10 nm or more, as the upper limit is preferably 100 nm or less, preferably 80 nm or less, further preferably 60 nm the following. An average particle diameter of 100 nm is below, even when such implementation, there are also the polyolefin with inorganic filling material is not easy to occur between the tendency of stripping, restraining large pore occurs from the point of view of a preferred. Here, the microporous membrane from a small fiber itself the point of view of high degree of hardness , preferably a polyolefin with inorganic filling material is not easy to occur the stripping between the, because of the microporous polyolefin film can be observed the withstand voltage of the local region can be excellent in the tendency of the tray or the tendency of excellent heat resistance, therefore preferred. Furthermore, the power storage device from the non-aqueous electrolyte the separator and for the affinity, the power maintaining performance, circulation to maintain the excellent performance of the point of view of separating member, preferably a polyolefin with inorganic filling material sealed between. On the other hand, from the to ensure that the dispersibility of the inorganic filling material, improve the withstand voltage of the partial area of the point of view of the tray, preferably the average particle size is 1 nm or more.

And, when the polyolefin resin is polyethylene-containing, from improving the compatibility of the polyethylene and polypropylene, to inhibit separation of the two, to ensure that the point of view of good stretchability, preferably in polyethylene and polypropylene-containing composition compounded in an average particle diameter of 1 nm or more 100 nm the following inorganic filling material.

As the inorganic filling material of plasticizer oil absorption, is preferably more than 150 ml/100g, as the upper limit is preferably 1000 ml/100g or less, more preferably 500 ml/100g the following. From the inhibit the polyolefin resin-containing, inorganic filling material, plasticizer generated in the aggregate reading, to ensure good the point of view of formability, to preferably make the oil absorption of 150 ml/100g or more. Furthermore, the use of polyolefin microporous membrane as a separator for the storage equipment, including soaks the nature from the non-aqueous electrolyte, excellent liquid-binding power, to ensure that electricity storage device productivity, maintenance in long-term use of the point of view of the performance of the preferred. On the other hand, from the production of polyolefin microporous film of inorganic filling material of of the point of view of handling properties, preferably the oil absorption of from 1000 ml/100g the following.

The inorganic filling material in the inorganic filling material and the total amount of the polyolefin resin is preferably in the proportion of 1 mass % or more, more preferably 5 mass % or more, further preferably 20 mass % or more, as the upper limit is preferably 80 mass % or less, more preferably 60 mass % or less, further preferably 50% of the following quality, especially preferably 40% of the following quality.

Film-forming polyolefin microporous membrane from a viewpoint of high porosity, improve the polyolefin microporous film 140 °C lower in the horizontal (width direction, TD direction) the view of heat shrinkage, and then from the creep (puncturecreep) retention of film thickness, the film thickness reduction rate adjustment to a small point of view, the proportion is preferably 1 mass % or more. Furthermore, from the point of view of improving heat-resistance, the ratio is preferably 20 mass % or more.

On the other hand, under high stretching ratio from the forming property, improve the puncture strength of polyolefin microporous membrane perspective, the ratio is preferably 80% of the following quality.

Furthermore, the inorganic filling material in the in the polyolefin resin is preferably the volume ratio of 10 volume % or more, more preferably to 15 volume % or more, more preferably 20% more than the volume, as the upper limit is preferably 80% volume.

Furthermore, the proportion of the inorganic filling material is preferably 1.0g/cm³ more, more preferably 1.2g/cm³ more, more preferably 1.5g/cm³ the above, as the upper limit is preferably 10.0g/cm³ the following.

The embodiment 2 of the polyolefin microporous film can also contain various additive.

As this kind of additive, can use the phenol-based antioxidant, phosphorus-based antioxidant, sulfur-based antioxidant, and the like; calcium stearate, zinc stearate and other metal soap; ultraviolet absorber, light stabilizer, antistatic agent, against dizzy medicinal preparation , various additives, such as coloring pigment. These and the addition amount of the additive relative to the polyolefin resin composition (the following also referred to as "polyolefin composition". ) Is preferably 0.01% or more the quality of the 1% of the following quality.

This embodiment is 2 laminated polyolefin microporous membrane through in the above-mentioned polyolefin microporous membrane is laminated on at least one side with the polyolefin microporous film of different other polyolefin microporous membrane and into. Low fusing function from other such as to the point of view of performance, this is preferably made of laminated polyolefin microporous membrane. From the point of view of productivity, more preferably the surface of the composition of the two layers of the same, the intermediate layer is a different two kinds of the shape of the three layers.

To note, as other polyolefin microporous film can be a known microporous membrane.

As the polyolefin microporous the membrane or states laminated microporous polyolefin film manufacturing process and without particular limitation, can be used, for example, containing the following (1)-(5) the method for manufacturing of the process.

(1) according to the required layer, as each layer of the raw material polyolefin composition and plasticizer mixing, the mixing process to form a method.

(2) after the mixing process, which according to the required layer of each layer of the raw material will be extruded into sheet, according to the requirements and the laminate is cooled and solidified, is processed into a sheet-shaped molded body (single-layer molded product or are stacked in a body) of the sheet forming process.

(3) after the shaping process, surface magnification 20 times more than 200 times the following to the flaky molded article is subjected to biaxial stretching, the stretching process forming inhibitor.

(4) after the stretching process, extracting plasticizer from the stretched, porous body forming step of forming a porous body.

(5) in the porous body after the forming process, the below the melting point of the polyolefin resin to the temperature of the porous body is subjected to heat treatment, stretching in the width direction of the heat treatment process.

As the process (1) of the plasticizer used in, preferably in the compounded with the polyolefin resin the polyolefin resin can be formed above the melting point of the volatile solvent of the solution. Furthermore, preferably at room temperature the liquid.

As the plasticizer, can be cited, for example, liquid paraffin, paraffin hydrocarbon; phthalic acid diethyla hexyl acrylate or dibutyl phthalate esters such as; oleyl alcohol, stearyl alcohol, and the like, such as higher alcohols.

From the inhibit the surface of the polyolefin resin and plasticizer stripping, the views of the drawing to apply a uniform or to realize high puncture strength point of view, in the polyolefin resin is particularly preferred in use the liquid paraffin containing polyethylene when used as a plasticizer. Furthermore, the reading from the load at the time of melt-extrudable, improve the dispersibility of the inorganic filling material (good film quality) point of view, it is preferred to use a phthalic acid diethyla caproite.

The plasticiser in the mixing proportion of in is preferably 25 mass % or more, more preferably 30 mass % or more, as the upper limit is preferably 80% of the following quality, more preferably 75% of the following quality. When the melt formed from the height of the melt tension, ensure that the point of view of formability, the ratio is preferably 80% of the following quality. On the other hand, high-efficient from the guarantee formability and expandering polyolefin crystallization in the region of the point of view of the lamella, preferably so that the proportion is 25% more than the quality. Here, the high-efficient stretching platelet polyolefine chain refer to the condition of rupture does not occur under high-efficient stretching polyolefine chain , can contribute to the formation of fine hole structure, the strength of the polyolefin microporous membrane and the improvement of the degree of crystallization.

As mixing polyolefin resin, inorganic filling material and a plasticizer method of, for example, can be cited the following (a), (b) method.

(A) of the polyolefin resin and inorganic filling material into the extruder, the resin mixing device in the kneading machine, the resin heating molten milling, on milling a method of introducing a plasticizer.

(B) by use of Henschel mixer or the like to provide the polyolefin resin, inorganic filling material and a plasticizer process of mixing in advance, the kneaded product while in the extruder, while heating the melt mixing method of introducing a plasticizer.

In the (b) method while mixing in advance, from improving the dispersibility of the inorganic filling material, the rupture does not occur under the condition of high implementation perspective drawing of the multiplying factor, preferably in the polyolefin resin and the inorganic filling material compounding in the equation below in (1) is set within the range of the amount of the plasticizer pre-mixing.

The 0.6 [...] plasticizer weight / (plasticizer oil absorption × inorganic filling material weight × plasticizer density) × 100 the [...] 1.2 (1)

The process (2), such as for example, by means of the covering method T die head for extruding a sheet, contacting it with the heat conducting body is cooled and solidified, the process of the gel sheet is obtained. when material in forming laminated to produce gel sheets, can be used to manufacture either of the following method: the various extruder with the composition of the gel sheet material of each layer of the integrated, using one die to carry out co-extrusion method; that will form each layer of the gel sheet overlap for hot melt method. Wherein the method of the co-extrusion is easy to obtain high interlaminar bonding strength, but also, because the interlayer is easy to form the communication hole, so it is easy for the maintenance of high permeability, excellent productivity, therefore even more preferred. As the heat conductor, can use the metallic, water, air or plasticizer itself.

Furthermore, from the increase in film strength of the sheet-shaped molded body or improve the view of the surface of the sheet-shaped molded body the point of view of smoothness, preferably through the implementation of the clamping between the rollers is cooled and solidified.

As the process (3) the stretching method, can be cited, for example, simultaneous biaxial stretching, successive biaxial stretching, multi-stage stretching, the stretching method for a plurality of times. Wherein increasing polyolefin microporous membrane from puncture strength or film thickness of a point of view, preferably using simultaneous biaxial stretching method.

Furthermore, the process (3) surface multiplying factor is preferably 10 times or more, more preferably 15 times, the upper limit is preferably 200 times or less, more preferably 100 times or less. To ensure that as the full of the separator from the point of view of strength, the surface is preferably 10 times or more.

As the process (3) stretching temperature, the melting point of the polyolefin resin to the reference temperature is preferably the temperature of the (melting point temperature -50 ° C) or more, more preferably (melting point temperature -30 ° C) the above, preferably further (melting point temperature -20 ° C) above, as the upper limit is preferably (melting point temperature -2 ° C) the following, more preferably (melting point temperature -3 ° C) the following. From the polyolefin resin and inorganic filling material or the interface of the interface of the polyolefin resin and plasticizer good sealing, the local of polyolefin microporous membrane and micro-small area of the point of view of pressure compression performance, preferably make the stretching temperature is (melting point temperature -50 ° C) above. For example, the use of high density polyethylene as the polyolefin resin, suitable for tensile temperature to 115 °C more than and 132 °C the following, using a plurality of polyolefin is compounded, the melt-down, a large amount of heat can be the melting point of the polyolefin as a reference.

Polyolefin microporous membrane from the puncture strength point of view, the process (4) preferably in the process (3) carried out after. As an extraction method, the inhibitor can be cited the plasticiser is dipped in the method in a solvent. To illustrate, after extracting the plasticizer in the microporous membrane of the residual stock preferably less than 1 mass %.

The process (5) is preferably heat-fixed and/or thermal relaxation process.

Here, as a process (5) stretching ratio of, the surface ratio is preferably less than 4 times, more preferably less than 3 times. The capillary from the inhibit the occurrence, or puncture strength reduction point of view, preferably making the magnification is less than 4 times.

Furthermore, as the heat treatment temperature, the melting point of the polyolefin resin is preferably temperature as a reference 100 °C the above, as the upper limit is preferably a polyolefin the melting point temperature of the following. Inhibiting membrane rupture from the point of view, preferably make the heat treatment temperature is 100 °C the above. On the other hand, from the inhibit contraction of the polyolefin resin, the polyolefin microporous membrane is reduced the point of view of thermal shrinkage, the temperature is preferably below the melting point of the polyolefin.

To note, in the process (5) the rear, can also be the resulting polyolefin microporous membrane implementation of after-treatment. As this kind of after-treatment, for example, using surface active agents and the like can be cited the hydrophilization treatment or use, such as ionization radiation, such as the cross-linking treatment.

In the embodiment 2 of the polyolefin microporous film or laminated polyolefin microporous membrane (sometimes only iota as "microporous membrane"), its puncture strength is preferably more than 200g/20 µm, more preferably more than 240g/20 µm, more preferably more than 300g/20 µm, as the upper limit is preferably 2000g/20 µm the following, more preferably 1000g/20 µm the following. When winding from inhibiting the battery the falling off of the active material to the point of view of the rupture of the membrane, preferably make the puncture strength is more than 200g/20 µm. Furthermore, from the inhibit the charging and discharging of the electrode by short circuit caused by expansion and contraction of the point of view of the uncertainties are also preferably. On the other hand, since the heating can be reduced when the from the orientation of the width of the slack caused by the contraction point of view, preferably 2000g/20 µm the following.

To note, the above-mentioned puncture strength can adjust the stretching ratio, adjusted stretching temperature, and the like.

states the micro porous membrane of the porosity is preferably 20% or more, more preferably 35% or more, as the upper limit is preferably 90% or less, more preferably 80% of the following. To ensure that the separating part from the viewpoint of permeability, preferably make the porosity is 20% or more. On the other hand, from the point of view of ensuring that the puncture strength, preferably 90% the following.

To note, the porosity can be controlled by changing the stretching ratio is adjusted.

The aperture is preferably the average states the micro porous membrane 0.1 µm the following, more preferably 0.8 µm the following, as a lower limit is preferably 0.01 µm the above. From the inhibit the self-discharge of storage equipment, the point of view of inhibiting reduce the capacity, preferably make the average pore diameter is 0.1 µm the following.

To note, the above-mentioned average pore diameter by changing the stretching ratio can be adjusted.

The film thickness of the film is preferably states micro porously 2 µm more, more preferably 5 µm the above, as the upper limit is preferably 100 µm the following, more preferably 60 µm the following, further preferably 50 µm the following. From the point of view of improving the mechanical strength, preferably make the film thickness is 2 µm the above. On the other hand, preferably make the film thickness is 100 µm the following, the reason for this is because of the separator occupies the volume is reduced, the high capacity of the battery the tendency of a beneficial aspect.

The air permeability of the states the micro porous membrane is preferably more than 10 sec/100cc, more preferably more than 50 sec/100cc, as the upper limit is preferably 1000 sec/100cc the following, more preferably 500 sec/100cc the following. Inhibiting storage equipment from the point of view of the self-discharge is preferably make the air permeability of more than 10 sec/100cc. On the other hand, to obtain good from the viewpoint of charge and discharge characteristics of a, preferably 1000 sec/100cc the following.

To note, the permeability can be changed by changing stretching temperature, adjusted stretching ratio.

The embodiment 2 of the polyolefin microporous film as the use of non-aqueous electrolyte of a storage apparatus particularly useful by a separate member. Storage devices are usually used in the divider of the above-mentioned porous membrane, containing the anode, cathode and electrolyte.

The storage device may, for example, the following manufacturing: the wide film states micro porously 10-500mm (preferably 80-500mm), long 200-4000m (preferably 1000-4000m) of the longitudinal shape of the separator, the separating member to positive-divider-negative-divider or negative-divider-positive-spacers overlap the order of a, coiled into circular or flat swirl, coiling body is obtained, the winding body is in the battery container, and then into the electrolyte, thereby manufacturing. Furthermore, the storage devices may also be manufactured by the following process: in positive-divider-negative-divider or negative-divider-positive-spacers stacked in sequence of the flat-plate-like, using bag-shaped thin film is laminated, the process of injecting electrolyte.

[Article 3 embodiment]

Paragraph of this invention 3 embodiment (the following also iota as " this embodiment the 3 [...]) of the polyolefin microporous film is characterized in that, the use of containing (polypropylene) / (propylene copolymer) (mass ratio) is 80/20 to 0/100 polypropylene resin as a main component of a propylene resin composition, the melting point of the copolymer states the propylene 120 °C the above 145 °C the following.

Here, as in this embodiment can be realized by adopting the above-mentioned a good cycle characteristics of a storage device used for reasons of the separator is not clear, but the following conjecture.

In other words, this embodiment is 3 compounding in the polypropylene and having a specific melting point of the propylene copolymer (propylene-ethylene copolymer or a propylene-α-olefin copolymer), the propylene-ethylene copolymer of ethylene component, propylene-α-olefin copolymers with reduced α-olefin part of the role of the crystallization degree of the polypropylene. Believe that this is because the propylene-ethylene copolymer of ethylene component, propylene-α-olefin copolymer of an α-olefin part of the polypropylene part, is formed in the sheet of the polypropylene part can be adjusted to a suitable thickness. And, when the appropriate thickness of the majority of the produced sheet, the formation of microporous membrane is produced when a great many with the small hole.

In addition that, the propylene-ethylene copolymer or a propylene-α-olefin random copolymer is set to be the melting point of 120 °C the above 145 °C the following specific range, improving the stretchability of the entire composition, the aperture becomes larger.

When the this kind that has a plurality of large a size and aperture in the hole of the porous membrane is disposed on the interior of the battery, ions are not no thick dense through the flow path, are presence of texture, the repeated charging and discharging when the blockage is not easy to occur, improving the cycle characteristics of the battery.

This embodiment is 3 containing the polyolefin microporous film is formed by polypropylene and propylene copolymer polypropylene resin as a main component to form a polypropylene resin composition.

As the polypropylene, for example can be cited of isotactic polypropylene, atactic polypropylene. These polypropylene can use 1 or compounding the use of 2 or more kinds.

Furthermore, the heat of fusion of the polypropylene by preferably 80J/g more, more preferably 85J/g more, more preferably 90J/g the above. From the perspective of the porosity, the polypropylene preferably make the the heat of fusion of the 80J/g the above.

On the other hand, the propylene copolymer (propylene-ethylene copolymer or a propylene-α-olefin copolymer) used as the monomer propylene and as different monomer with the propylene ethylene or α-olefin formed.

As this kind of α-olefin, can be cited, for example, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene, and the like. To note, the propylene-ethylene copolymer or a propylene-α-olefin copolymer to ethylene or α-olefin in the case of the position of the polymer chain, can be a block copolymer can also be a random copolymer, from improved stretchability, the point of view of increasing the aperture, preferably random copolymers.

The porosity of the microporous polyolefin film from the point of view of, propylene-ethylene copolymer or a propylene-α-olefin copolymer is preferably the heat of fusion of the 60J/g more, more preferably 65J/g more, more preferably 70J/g the above.

From the point of view of improving the porosity, preferably the propylene-ethylene copolymer or a propylene-α-olefin copolymer to the heat of fusion of the 60J/g the above.

In the propylene copolymer of ethylene or α-olefin content of more than 1 mass % and 20% of the following quality, is preferably 2 mass % or more and 18% of the following quality. The content of more than 1% can contribute to the quality of the improvement of the battery properties. On the other hand, the resulting microporous membrane from improving heat resistance, improve the point of view of safety of the battery, preferably 20% of the following quality.

Furthermore, the propylene copolymer polypropylene-based resin in the proportion of in is preferably 20 mass % or more, more preferably 25 mass % or more, more preferably 30 mass % or more, as a limit for a 100% quality the following.

The polyolefin microporous film from a hole of the view is increased, under the high stretching ratio membranaceous to make point of view, the ratio is preferably 20 mass % or more.

Furthermore, the melting point of the propylene copolymer is 120 °C more, preferably 122 °C more, further preferably to 125 °C the above, as a limit for a 145 °C the following, preferably 143 °C the following, further preferably 140 °C the following.

From the point of view of improving the stretchability, preferably make the melting point of the propylene copolymers is 120 °C the above.

To note, the polypropylene resin composition in addition to the above-mentioned polypropylene, propylene copolymer outside, can also be incorporated with the other resin component.

As the other resin component, with the above-mentioned examples of the embodiment 2 is the same as the material of the example.

As the polypropylene-based resin composition, the resulting polyolefin microporous membrane from the puncture strength point of view, preferably comprising high-density polyethylene.

High-density polyethylene in the polypropylene resin composition is preferably in the proportion of 5 mass % or more, more preferably 10 mass % or more, as the upper limit is preferably 50% of the following quality. From improved heat resistance, improve battery safety point of view, preferably the proportion of the high-density polyethylene to 50% of the following quality.

To note, the polypropylene in the polypropylene resin composition is preferably in the proportion of 0 mass % or more, more preferably 20 mass % or more, as the upper limit is preferably 80% of the following quality. From the point of view of improving the stretchability, preferably polypropylene is the ratio of the 80% of the following quality.

As the above-mentioned various components of the viscosity average molecular weight (using a plurality of component means the various components of the value of the measured) is preferably 10 million or more, more preferably 12 million or more, as the upper limit is preferably 1000 million the following, more preferably 300 million the following. When the melt formed from the height of the melt tension, to ensure good formability to the views of the full complex, or from, the standpoint of the strength of a microporous membrane, preferably the viscosity average molecular weight is 10 million or more. On the other hand, a from the melt mixing, the formability of the sheet material, in particular the thickness of the point of view of stability, preferably make the viscosity average molecular weight is 1000 million the following. From the point of view of formability, preferably make the viscosity average molecular weight is 300 million the following.

The polyolefin resin can be cited in the above-mentioned the embodiment 1 is the same as the example of the material. Furthermore, its matches mixes the quantity also with the embodiment 1 are the same.

The embodiment 3 of the polyolefin microporous film preferably contains polypropylene resin as a main component. Here, the "main component" refers to, polypropylene-based resin in the polypropylene resin composition is preferably in the proportion of 20 mass % or more, more preferably 30 mass % or more, further preferably 40 mass % or more, especially preferably 45% more than the quality. To note, as the upper limit is preferably 100% of the following quality.

The embodiment 3 of the polyolefin microporous film can also contain inorganic filling material.

As this kind of inorganic filling material, with the above-mentioned can be cited of the embodiment 2 is the same as the example in the material.

The inorganic filling material is preferably a particle size of 1 nm or more, more preferably 6 nm or more, further preferably 10 nm or more, as the upper limit is preferably 100 nm or less, more preferably 80 nm or less, further preferably 60 nm the following. From even in the implementation of the stretching isochronous also a polyolefine and inorganic particles is difficult to occur between the tendency of the stripping of, inhibit the occurrence of from the point of view of the capillary, a primary particle size of preferably 100 nm the following. Here, polyolefin and inorganic filling material is difficult to be occurred from the stripping between the porous membrane of a small fiber itself the point of view of high degree of hardness preferably, the reason for this is that local area of polyolefin microporous membrane can be excellent pressure resistance of the tendency of the tray or the tendency of excellent heat resistance. Furthermore, the power storage device from the non-aqueous electrolyte the separator and for the affinity, to achieve the output power to maintain performance, excellent cycle performance of the point of view of the separating member, preferably a polyolefin with inorganic filling material sealed between.

As the inorganic filling material of plasticizer oil absorption, is preferably more than 150 ml/100g, as the upper limit is preferably 1000 ml/100g or less, more preferably 500 ml/100g the following. From the containing polyolefin resin, inorganic filling material, mixing a plasticizer in the production of aggregate, to ensure good the point of view of formability, to preferably make the oil absorption of 150 ml/100g or more. Furthermore, from the use of polyolefin microporous film as a storage device by a separate piece of non-aqueous electrolyte the including soaks the nature , excellent liquid-binding power, to ensure that electricity storage device productivity, maintenance during long-term use, the point of view of the performance of the preferred. On the other hand, from the production of polyolefin microporous film of inorganic filling material of of the point of view of handling properties, preferably the oil absorption of from 1000 ml/100g the following.

The inorganic filling material in the propylene resin composition is preferably in the proportion of 5 mass % or more, more preferably 10 mass % or more, further preferably 20 mass % or more, as the upper limit is preferably 60 mass % or less, more preferably 50 mass % or less, further preferably 40% of the following quality.

Film-forming polyolefin microporous membrane from a viewpoint of high porosity, improve the polyolefin microporous film 140 °C lower in the horizontal (width direction, TD direction) of the views of the heat shrinkage, creep and the puncture from the retention of film thickness, the film thickness reduction rate adjustment as relatively small point of view, the ratio is preferably 5 mass % or more. Furthermore, from the point of view of improving heat-resistance, the ratio is preferably 20 mass % or more.

On the other hand, under high stretching ratio from the forming property, improve the puncture strength of polyolefin microporous membrane perspective, preferably so that the proportion is 60% of the following quality.

Furthermore, the inorganic filling material in the propylene resin composition in the preferably the volume proportion of 10% more than the volume, more preferably to 15 volume % or more, more preferably 20% more than the volume, as the upper limit is preferably 80% of the volume.

Furthermore, the proportion of the inorganic filling material is preferably 1.0g/cm³ more, more preferably 1.2g/cm³ more, more preferably 1.5g/cm³ the above, as the upper limit is preferably 10.0g/cm³ the following.

In the propylene resin composition may further contain various additive.

As this kind of additive can cite and the above-mentioned the embodiment 2 is the same as the example in the material.

This embodiment is 3 laminated polyolefin microporous film in the above-mentioned polyolefin microporous membrane is laminated on at least one side with the polyolefin microporous film of different other polyolefin microporous membrane. Low fusing function from other such as to the point of view of performance, this is preferably made of laminated polyolefin microporous membrane. From the point of view of productivity, more preferably the surface layer of a two layer is the same, the intermediate layer is a different two kinds of the shape of the three-layer structure.

To note, as other polyolefin microporous film can be a known microporous membrane.

As the polyolefin microporous the membrane or states method for manufacturing laminated microporous polyolefin film, can be used with the above-mentioned the embodiment 2 of the manufacturing method for the same.

For the embodiment 3 of the polyolefin microporous film or laminated polyolefin microporous membrane (sometimes only iota as "microporous membrane") speaking, its puncture strength, porosity, average pore diameter, the film thickness, the preferred value range of the air permeability of the above-mentioned the embodiment 2 is the same.

The cycle characteristics of the laminated divider as capacity maintaining rate of the indicators is preferably 70% or more, more preferably 75%. From the point of view of service life of the battery, preferably make the capacity maintenance ratio is 70% or more.

Laminated divider high-temperature storage characteristics is preferably 60% or more, more preferably 65% or more. The point of view of service life from the battery, the high-temperature preservation characteristic is preferably 65% or more.

Laminated spacers as the index of the heat resistance temperature is preferably a short 160 °C more, more preferably 165 °C the above. From the point of view of safety of the battery, preferably make the short-circuit temperature is 160 °C the above.

states micro porously film as the use of non-aqueous electrolyte of a storage apparatus particularly useful by a separate member. Storage devices are usually used in the divider of the above-mentioned porous membrane, containing the anode, cathode and electrolyte.

The storage apparatus can be through with the above-mentioned the embodiment 2 of the method for manufacturing the same.

[Section 4 embodiment]

Paragraph of this invention 4 embodiment (the following also iota as " this embodiment the 4 [...]) containing the polyolefin microporous film (polypropylene) / (propylene copolymer) (mass ratio) is 90/10 to 0/100 polypropylene resin 20-95 quality and % inorganic filling material 5-80 mass % of a polypropylene resin composition, characterized in that the propylene copolymer is the melting point of 110 °C -150 °C, propylene copolymers with inorganic filling material mass ratio is 0.1/1-1.5/1.

To note, the "propylene copolymerization" refers to the "propylene-ethylene copolymer or a propylene-α-olefin copolymer".

Here, in the embodiment 4 by adopting such a constitution can realize good cycle characteristics of a storage device is not clear for reasons of the separator, supposed as follows.

In other words, this embodiment is 4 in, the presence of the compounding of the polypropylene having a specific melting point of the propylene copolymer and inorganic filling material. In the inorganic filling material compounding a certain amount of this kind the specific propylene copolymer, the polypropylene of the region of the melting temperature of the propylene copolymer can be good interaction on polypropylene and inorganic filling material, the result of the molten state the fluidity of the resin can be reduced as a whole. In even in the raw materials containing low molecular weight ingredient or crystallization of the polymer component is low, reducing the mobility of the whole resin, it can also inhibit this kind of ingredient in the preparation of the membrane from the surface of the microporous membrane, so that the surface layer it is difficult to form. The surface layer may be formed to cause in micro porous structural damage the holes of the surface of the film (hole is blocked). In other words, in this embodiment the formation of the inhibiting surface can be realized, with the surface layer of the hole cannot be blocked, is provided with a plurality of a size of the microporous film hole. When the kind of the porous membrane is disposed on the interior of the battery, ions are not no thick dense through the flow path, are presence of texture, the repeated charging and discharging when the clogging will not occur, as the cycle characteristics of the battery.

The embodiment 4 containing the polyolefin microporous film is formed by polypropylene and propylene copolymer polypropylene resin and inorganic filling material to form a polypropylene resin composition.

As the polypropylene, for example can be cited of isotactic polypropylene, atactic polypropylene. These polypropylene can use the 1 use or a combination of 2 or more kinds.

The polyolefin microporous membrane from the high-temperature preservation characteristic and membranaceous to make point of view, the MFR of the propylene ("melt index" refer to, the following same. ) Preferably 0.1g/10 minutes 10.0g/10 minutes, more preferably 8.0g/minutes, more preferably 5.0g/minutes.

Furthermore, the heat of fusion of the polypropylene by preferably 80J/g more, more preferably 85J/g more, more preferably 90J/g the above. From the perspective of the porosity, the polypropylene preferably make the the heat of fusion of the 80J/g the above.

On the other hand, the propylene copolymer (propylene-ethylene copolymer or a propylene-α-olefin copolymer) used as the monomer propylene and as different monomer with the propylene ethylene or α-olefin formed.

As this kind of α-olefins can be cited, for example, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene, and the like. To note, in the propylene-ethylene copolymer, said propylene-α-olefin in the copolymer, the ethylene or α-olefin in the case of the position of the polymer chain, can be a block copolymer can also be a random copolymer, preferably random copolymers.

The propylene copolymer of acrylic resin in the proportion of in is preferably 10 mass % or more, more preferably 15 mass % or more, further preferably 20 mass % or more, as a limit for a 100% of the following quality, more preferably 80 mass % or less, further preferably 60% of the following quality.

The polyolefin microporous film from a hole of the view is increased, under the high stretching ratio membranaceous to make point of view, the ratio is preferably 10 mass % or more.

Furthermore, the melting point of the propylene copolymer is 110 °C more, preferably 115 °C the above, preferably further 120 °C the above, as a limit for a 150 °C the following, preferably 147 °C the following, further preferably 145 °C the following.

From the point of view of improving the stretchability, preferably make the melting point of the propylene copolymers is 110 °C the above.

Membranaceous to make polyolefin microporous membrane from the point of view, preferably the MFR propylene copolymer 0.1g/10 minutes 20.0g/10 minutes, more preferably 15.0g/10 minutes, more preferably 10.0g/10 minutes the following.

Furthermore, the heat of fusion of the propylene copolymer is preferably 60J/g more, more preferably 65J/g more, more preferably 70J/g the above.

From the point of view of improving the porosity, preferably the heat of fusion of the propylene copolymer is 60J/g the above.

In the propylene copolymer content of the comonomer (ethylene and α-olefin content) for more than 1 mass % and 20% of the following quality, is preferably 2% or more the quality of 18% of the following quality. The content of more than 1% can contribute to the quality of the improvement of the battery properties. On the other hand, the resulting microporous membrane from improving heat resistance, improve the point of view of safety of the battery, preferably 20% of the following quality.

To note, the polypropylene resin composition in addition to the above-mentioned polypropylene or propylene copolymer outside, can also be incorporated with other resin component.

As the other resin component can cite and the embodiment 2 is the same as the example of the material.

As the polypropylene-based resin composition, the resulting polyolefin microporous membrane from the puncture strength point of view, preferably containing a high-density polyethylene.

High-density polyethylene in the polypropylene resin composition is preferably in the proportion of 5 mass % or more, more preferably 10 mass % or more, as the upper limit is preferably 60% of the following quality. From improved heat resistance, improve battery safety point of view, preferably make the high-density polyethylene is the ratio of 60 mass % the following.

The above-mentioned various components of the viscosity average molecular weight (using a plurality of component means the various components of the value of the measured) is preferably 10 million or more, more preferably 12 million or more, as the upper limit is preferably 1000 million the following, more preferably 300 million the following. When the melt formed from the height of the melt tension, to ensure good formability to the views of the full complex, or from, the standpoint of the strength of a microporous membrane, preferably the viscosity average molecular weight is 10 million or more. On the other hand, a from the melt mixing, the formability of the sheet material, in particular the thickness of the point of view of stability, preferably make the viscosity average molecular weight is 1000 million the following. From the point of view of formability, preferably make the viscosity average molecular weight is 300 million the following.

The polyolefin resin can be cited in the above-mentioned the embodiment 1 is the same as the example of the material. Furthermore, its matches mixes the quantity also with the embodiment 1 are the same.

The embodiment 4 of the polyolefin microporous film preferably contains polypropylene resin as a main component. Here, the "main component" refers to polypropylene-based resin in the polypropylene resin composition is preferably in the proportion of 20 mass % or more, more preferably 30 mass % or more, further preferably 40 mass % or more, especially preferably 45% more than the quality. To note, as the upper limit is preferably 95 mass % the following.

The embodiment 4 of the polyolefin microporous film can also contain inorganic filling material.

As this kind of inorganic filling material, with the above-mentioned can be cited of the embodiment 2 is the same as the example in the material.

As the inorganic filling material is preferably a particle size of 1 nm or more, more preferably 6 nm or more, further preferably 10 nm or more, as the upper limit is preferably 100 nm or less, more preferably 80 nm or less, further preferably 60 nm the following. A primary particle size of preferably 100 nm the following, the reason for this is, even in the implementation of the stretching isochronous also a polyolefine and inorganic particles is difficult to occur between the tendency of the stripping of, inhibit the occurrence of from the point of view of the capillary is preferably. Here, polyolefin and inorganic filling material is difficult to be occurred from the stripping between the porous membrane of a small fiber itself the point of view of high degree of hardness preferably, the reason for this is that local area of polyolefin microporous membrane can be excellent pressure resistance of the tendency of the tray or the tendency of excellent heat resistance. Furthermore, the power storage device from the non-aqueous electrolyte the separator and for the affinity, to achieve the output power to maintain performance, excellent cycle performance of the point of view of the separating member, preferably a polyolefin with inorganic filling material sealed between.

On the other hand, from the to ensure that the dispersibility of the inorganic filling material, improve the withstand voltage of the partial area of the point of view of the tray, preferably the average particle size is 1 nm or more.

And then, from improved polyethylene and polypropylene intermiscibility, inhibit separation of the two, to ensure that the point of view of good stretchability, preferably with respect to the composition of polyethylene and polypropylene-containing mixed particle size is 1 nm above 100 nm the following inorganic particles.

As the inorganic filling material of plasticizer oil absorption, is preferably more than 150 ml/100g, as the upper limit is preferably 1000 ml/100g or less, more preferably 500 ml/100g the following. From the inhibit the polyolefin resin-containing, inorganic filling material, plasticizer generated in the aggregate reading, to ensure good the point of view of formability, to preferably make the oil absorption of 150 ml/100g or more. Furthermore, from the use of polyolefin microporous film as a storage device by a separate piece of non-aqueous electrolyte the including soaks the nature , excellent liquid-binding power, to ensure that electricity storage device productivity, maintenance during long-term use, the point of view of the performance of the preferred. On the other hand, from the production of polyolefin microporous film of inorganic filling material of of the point of view of handling properties, preferably the oil absorption of from 1000 ml/100g the following.

The inorganic filling material in the inorganic filling material and the polyolefin resin in the proportion of the total amount is preferably 5 mass % or more, more preferably 10 mass % or more, further preferably 20 mass % or more, as the upper limit is preferably 80 mass % or less, more preferably 60 mass % or less, further preferably 50% of the following quality, especially preferably 40% of the following quality.

Film-forming polyolefin microporous membrane from a viewpoint of high porosity, improve the polyolefin microporous film 140 °C lower in the horizontal (width direction, TD direction) of the views of the heat shrinkage, creep and the puncture from the retention of film thickness, film thickness reduction rate will be adjusted to a very small point of view, the ratio is preferably 5 mass % or more. Furthermore, from the point of view of improving heat-resistance, the ratio is preferably 20 mass % or more.

On the other hand, under high stretching ratio from the forming property, improve the puncture strength of polyolefin microporous membrane perspective, the ratio is preferably 80% of the following quality.

Furthermore, the inorganic filling material in the propylene resin composition in the preferably the volume proportion of 10% more than the volume, more preferably to 15 volume % or more, more preferably 20% more than the volume, as the upper limit is preferably 80% of the volume.

Furthermore, the proportion of the inorganic filling material is preferably 1.0g/cm³ more, more preferably 1.2g/cm³ more, more preferably 1.5g/cm³ the above, as the upper limit is preferably 10.0g/cm³ the following.

As the copolymer states the propylenematches mixes the ratio with inorganic filling material, propylene copolymers with inorganic filling material mass ratio is 0.1/1-1.5/1, preferably 0.1/1-1.3/1, further preferably 0.1/1-1.2/1. From the use of low molecular weight polymer or a polymer of a low degree of crystallization is formed on the surface of the point of view of inhibiting, preferably make the compounding ratio is set to the above-mentioned range.

The propylene resin composition may further contain various additive.

As this kind of additive can cite and the above-mentioned the embodiment 2 is the same as the example in the material.

This embodiment is 4 laminated polyolefin microporous film in the above-mentioned polyolefin microporous membrane is laminated on at least one side with the polyolefin microporous film of different other polyolefin microporous membrane. Low fusing function from other such as to the point of view of performance, this is preferably made of laminated polyolefin microporous membrane. From the point of view of productivity, more preferably the surface layer of a two layer is the same, the intermediate layer is a different two kinds of the shape of the three layers.

To note, as other polyolefin microporous film can be a known microporous membrane.

As the polyolefin microporous the membrane or states method for manufacturing laminated microporous polyolefin film, can be used with the above-mentioned the embodiment 2 of the manufacturing method for the same.

In the embodiment 4 of the polyolefin microporous film or laminated polyolefin microporous membrane (sometimes only iota as "microporous membrane") speaking, its puncture strength, porosity, average pore diameter, film thickness, air permeability, capacity maintenance ratio, high-temperature storage characteristics, short-circuit temperature-related preferred numerical range with the above-mentioned the embodiments 2 and 3 the same.

states micro porously film as the use of non-aqueous electrolyte of a storage apparatus particularly useful by a separate member. Storage devices are usually used in the divider of the above-mentioned porous membrane, containing the anode, cathode and electrolyte.

The storage apparatus can be through with the above-mentioned the embodiment 2 of the method for manufacturing the same.

Explanation, this embodiment is 1-4 of the measured value of the above-mentioned various parameters without particular limitation to only, according to the latter with the embodiment of the method of the embodiment corresponding to the value of the determining.

Embodiment

[The embodiment 1]

Furthermore, comparative example embodiments cited more specifically illustrate the embodiment 1, but this embodiment is 1 as long as not exceeding its thrust is not limited to the following embodiment. To note, in the embodiment of the method is determined by using the following physical properties.

(1) (Mv) nien average molecular weight

Under ASTM-D4020, in the solvent in the calculation of decahydronaphthalene 135 °C lower intrinsic viscosity.

Mv of polyethylene obtained by using the following formula.

[η] =6.77 × 10^-4 Mv^0.67

Mv of polypropylene is obtained using the following formula.

[η] =1.10 × 10^-4 Mv^0.80

(2) (µm) total film thickness

With micro- thickness gauge (KBM dongyang fine mechanism models) in room temperature 23 °C lower determination.

(3) film thickness of the surface layer (µm)

Use of the scanning-type electronic microscope, such as the cross section of the cross section of the observation method for observing to determine the.

(4) particle size of the inorganic particles (nm) a

Divider from stratifying collecting measurement object, using the scanning type electron microscope to 30000 times observed, in the vertical 3.0 µm, transverse 3.0 µm identified in field-of-view Image of the inorganic particle size. Explanation, "a primary particle size" means that each particle dispersed alone in the substrate under the state of the particle size of the aggregation occurs or, wherein the most of the small particle size. Furthermore, the measured value of the 10 points average value of the observed value.

(5) the porosity (%)

Cut from the microporous membrane is 10 cm × 10 cm square sample, calculate its volume (cm³) and quality (g), and a film density by these values (g/cm³) calculated using the following formula.

Porosity (%) = (volume-quality/compounding composition density)/ volume × 100

To note, compounding the composition is used for the density of the polyolefin resin and the inorganic particles through matches mixes the ratio each density and calculating the value of the obtained.

(6) air permeability (sec/100cc)

Based on use JISP-8117 of permeability ideagurley type determining (Toyo fine mechanisms).

(7) puncture strength (N/20 µm)

Using KATOTECHCO., LTD. Systems, TM KES-G5 portable compressed tester, the front end of the needle with a radius of curvature of 0.5 mm, the puncture-speed 2 mm/sec under the condition of a puncture test, the maximum puncture load as the puncture strength (N). By multiplied by 20 (µm)/ film thickness (µm), calculate conversion into 20 µm puncture strength of the film thickness (N/20 µm).

(8) the obturator temperature (°C)

Figure 1 (A) of the obturator temperature measuring device that the outline of the Figure. 1 for the porous membrane (as determine the target's laminated divider), 2A and 2B the thickness 10 µm the nickel foil, 3A and 3B as the glass sheet. 4 is a resistance measuring device (an Tengelectrical system LCRmeter " AG-4311 the [...] (trade mark)), and the nickel foil 2A, 2B is connected. 5 is a thermoelectric couple, and the thermometer 6 is connected. 7 as a data collector, and resistance device 4 and thermometer 6 is connected. 8 for the dry oven, to heat the microporous film.

When to explain in more detail, as shown in Figure 1 (B) illustrated, the nickel foil 2A overlap on the porous membrane 1, used in the longitudinal direction "Teflon (registered trademark)" with (oblique line part of the graph) is fixed on the nickel foil 2A the upper. In the microporous membrane 1 as electrolyte impregnated in 1mol/L of boron fluorizating lithium solution (solvent: propylene carbonate/ethylene carbonate / γ-butyrolactone = 1/1/2). As shown in Figure 1 (C) illustrated, the nickel foil 2B laminate "Teflon (registered trademark)" with (oblique line part of the graph), and the foil 2B leaving the central portion of 15 mm × 10 mm of the window portion of the shielding.

In order to grasp the microporous membrane 1 form overlapping foil 2A and nickel foil 2B, and then utilize glass plate 3A, 3B from the nickel foil 2A and nickel foil 2B clamping the two sides of the 2 pieces of nickel foil. At this moment, foil 2B with the window part of the porous membrane 1 in a relative position.

2 sheets of glass plate by using a commercial double-clamp to clamp and fix the (doubleclip). Thermocouple 5 with "Teflon (registered trademark)" belt is fixed on the glass plate.

Use of this kind of device continuously measuring temperature and resistance. To note, the temperature from 25 °C to 2 °C/min speed heating to 200 °C, resistance to 1V, 1kHz exchange of measured under the condition of. The obturator temperature defined as the resistance value of the porous film to reach 10³ Ω the temperature of the.

(9) brazing test (mm²)

With the diameter of 1 mm of the welding according to the vertical for the fixed frame is a microporous film. The iron temperature is set to 300 °C or 400 °C. After the stable temperature, in order to 10 mm/sec in the iron, the microporous film puncture 3 seconds, then rise. The hole for the area of the optical microscope observation, graphics processing for the area.

(10) the capacity maintenance ratio (%)

A. Production of positive electrode

As a positive electrode active material of the lithium-cobalt composite oxide (LiCoO₂) 92.2 quality %, as the conductive material of the scaly graphite and acetylene black 2.3 mass %, as a binder polyvinylidene fluoride (PVDF) 3.2 mass % dispersed in N-methyl pyrrolidone (NMP) modulate the slurry. Utilizing the embossing coating (diecoater) as the slurry is coated on the thickness of the positive electrode collector 20 µm on one side of the aluminum foil, the 130 °C drying 3 minutes later, using press compression forming. At this moment, positive electrode active material for the coating 250g/m², active material bulk density is 3.00g/cm³.

B. Preparation of a negative electrode

The active material of the negative electrode as artificial graphite 96.9% quality, the carboxymethyl cellulose as a binder and ammonium salt 1.4 mass %, and styrene-butadiene copolymer latex 1.7% dispersion in the quality of refined water modulate the slurry. Through molding this slurry is coated on the coating will become the thickness of the current collector of negative pole 12 µm on one side of the copper foil, the 120 °C drying under 3 minutes later, using press compression forming. At this moment, the negative electrode active material for the coating 106g/m², active material bulk density is 1.35g/cm³.

C. The modulation of the non-aqueous electrolyte

In ethylene carbonate: methyl ethyl carbonate = 1:2 (volume ratio) mixed in the mixed solvent of solute LiPF₆ to make its concentration 1.0mol/L, for modulation.

D. Battery assembly

The spacers shear cut into 30 mm Ф circular, cut into the positive electrode and negative electrode of the round 16 mm Ф, in accordance with a positive electrode and a negative electrode of the active substance, to cathode, spacer, anode superposed in order, of the stainless steel cover is installed in the metal container. The insulating container and lid, the copper foil is connected with the negative electrode container, cover and the positive electrode is connected with aluminum foil. In this container into said non-aqueous electrolyte for sealing. Placed at room temperature for 1 day, then the 25 °C environment to under 2.0mA (0.33C) is charged to the voltage of the battery current value of 4.2V, after reaching the 4.2V, from 2.0mA begin to narrow the current value, by the same method to process a total of 8 hours, the initial charging of the battery. Furthermore, in order to 2.0mA (0.33C) the current value of the battery voltage discharge to 3.0 V.

E. Capacity maintenance ratio (%)

The charging and discharging in the 60 °C the implementation environment 100 times of circulation. Charging to 6.0mA (1.0C) is charged to the voltage of the battery current value of 4.2V, maintain the 4.2V, from 6.0mA begin to narrow the current value, charging by the method a total of 3 hours. In discharging 6.0mA (1.0C) the current value of the battery voltage discharge to 3.0 V. By section 100 and the discharge capacity of the secondary cycle of the section 1 the discharge capacity of the secondary cycle of the computational capacity maintenance ratio. Capacity maintenance ratio is high, the cycle characteristics of the evaluation has good.

[Embodiment 1-1]

Through the use of a super mixer the added with a primary particle size of 15 nm of SiO₂ "DM10C      (TM, TokuyamaCorporation systems using dimethyl dichloro silane implementation of the hydrophobic processing) 24.0 parts by mass of the (inorganic particle concentration is 60 mass %), nien average molecular weight (Mv) 200 million of ultra-high molecular weight polyethylene" the UH850 [...] (TM, the rising sun turns into chemical Corporation systems) 6.4 parts by mass (the polyolefin resin and the inorganic particles in the total amount is the ratio of 16% quality), Mv40 million are polypropylene "the H-100M [...] (PrimePolymerCo., Ltd systems) 9.6 parts by mass (the polyolefin resin and the inorganic particles in the total amount the proportion of 24 mass %), liquid paraffin as a plasticizer," the SMOILP-350P [...] (TM, society systemloose village petroleum Institute) 28.8 parts by mass, as antioxidant pentaerythritol-tetra-[ 3-(3, 5-di-tert-butyl-4-hydroxy-phenyl) propionate] 0.3 parts by mass of the material preparatory to mixing, modulating polyolefin section 1 micro porous level raw material.

In Mv70 the high-density polyethylene "the UH650 [...] (TM, the rising sun turns into chemical Corporation systems) 20 parts by mass (polyolefin resin in the total amount of 50 mass %), Mv27 the high-density polyethylene" the SH800 [...] (TM, the rising sun turns into chemical Corporation systems) 20 parts by mass (polyolefin resin in the total amount of 50 mass %)as an antioxidant is added in the pentaerythritol-tetra-[ 3-(3, 5-di-tert-butyl-4-hydroxy-phenyl) propionate] 0.3 parts by mass, modulation polyolefin section 2 micro porous level raw material.

The various raw materials from the feeder to the 2 stage double-shaft screw extruder in the same direction in the mouth machine gives the material. In accordance with the melt mixing, extrusion of the plasticized dose in the total mixture of up to 60% of the quality, will together with the raw material liquid paraffin, is fed to the double-shaft side in the extruder barrel. Extruder melt mixing conditions are as follows: section 1 in order to set the temperature of the raw materials of micro porous level 200 °C, screw speed 100rpm, spray amount of 5 kg/h to, section 2 in order to set the temperature of the raw materials of micro porous level 200 °C, screw speed 120rpm, spray amount of 16 kg/h carry out.

Furthermore, the melt-kneaded product while respectively by way of the temperature is set to be 220 °C gear pump, the conduit, can be 2 types 3 layer T die co-extrusion, extrusion to the surface the temperature is controlled as 30 °C in the roller, the surface temperature is 25 °C cooling of rolls, to obtain by the section 1 formed of raw materials micro porous level 1 layer is that the thickness of the surface layer 1200 µm sheet composition. Furthermore, continuously introduced into the to the double-shaft tentering machine, to longitudinal 7 times, the transverse 7 times of biaxial stretching at the same time. At this time, simultaneous biaxial tenter frame to the set temperature of the 123 °C. Then introduced into the extracting groove, fully impregnated in methylene chloride, to remove the liquid paraffin is extracted. After drying of methylene chloride. And then introduced into a tenter to horizontal is stretched in the TD direction 1.4 times the rear, according to the final outlet is achieved in the TD direction 1.2 times are relaxed, the implementation of the winding (table expressed as " 1.4-1.2 the [...]). TD is the set temperature of the expandering Department 120 °C, relaxation department to the set temperature of 125 °C (table expressed as " the 120-125 [...]). The characteristics of the resulting laminated divider shown in table 1.

[Embodiment 1-2-1-17, comparative example 1-2]

In addition to table 1 and 2 other than the condition of the, and embodiment 1-1 similarly obtain laminated divider. The results are shown in table 1 and 2.

[Embodiment 1-18]

The polyolefin section 1 for the raw material micro porous level 24.0 parts by mass of a particle size of 15 nm of SiO2, 5.1 parts by mass of a viscosity average molecular weight (Mv) 27 million of ultra-high molecular weight polyethylene, 1.3 parts by mass of (Mv) 1000 having a viscosity average molecular weight of the polyethylene, 9.6 parts by mass of a Mv40 million are polypropylene, in addition, with the embodiment 1-1 similarly obtain laminated divider.

The resulting laminated divider closed cell characteristic is excellent.

To note, the composition of various raw materials are as follows.

[Inorganic particle]

SiO₂: average particle size is 15 nm silicon dioxide " the DM10C [...] (TM, TokuyamaCorporation systems. With dimethyl dichloro silane implementation of the hydrophobic processing).

Al₂ O₃: average particle diameter of 13 nm -100 nm of the various commercial alumina.

[PP]

Mv40 million: Mv to 40 million are polypropylene " the H-100M [...] (PrimePolymerCo., Ltd systems).

[PE]

Mv200 million: Mv to 200 million of ultra-high molecular weight polyethylene " the UH850 [...] (TM, the rising sun turns into chemical Corporation systems).

Mv70 million: Mv to 70 million high-density polyethylene " the UH650 [...] (TM, the rising sun turns into chemical Corporation systems).

Mv27 million: for Mv 27 million high-density polyethylene " the SH800 [...] (TM, the rising sun turns into chemical Corporation systems).

[Comparison example 1-1]

Through the use of super-mixer to the added with an average primary particle size of 15 nm silicon dioxide "the DM10C [...] (TM, TokuyamaCorporation systems using dimethyl dichloro silane implementation of the hydrophobic processing) 24.0 parts by mass, having a viscosity average molecular weight (Mv) 200 million of ultra-high molecular weight polyethylene" the UH850 [...] (TM, the rising sun turns into chemical Corporation systems) 6.4 parts by weight, Mv40 million are polypropylene "the H-100M [...] (PrimePolymerCo., Ltd systems) 9.6 parts by mass, liquid paraffin as a plasticizer," the SMOILP-350P [...] (TM, society systemloose village petroleum Institute) 28.8 parts by mass, as antioxidant pentaerythritol-tetra-[ 3-(3, 5-di-tert-butyl-4-hydroxy-phenyl) propionate] 0.3 parts by mass of a substance premix, modulation raw materials.

The raw materials from the feeding machine to the 1 stage double-shaft screw extruder in the same direction in the mouth machine gives the material. In accordance with the melt mixing, extrusion of the plasticized dose in the total mixture of up to 60% of the quality of the liquid paraffin is fed to the double-shaft side in the extruder barrel. The melt mixing conditions in the extruder in order to presume the temperature 200 °C, screw speed 150rpm, spray amount of 20 kg/h carried out. Furthermore, the melt-kneaded product while respectively by way of the temperature is set to be 220 °C gear pump, conduit, single-layer T die head, for the control of surface temperature to 30 °C in the roller, the surface temperature is controlled to be 25 °C cooling of rolls, the thickness of the obtained 1200 µm sheet composition. Furthermore, continuously introduced into the to the double-shaft tentering machine, to longitudinal 7 times, the transverse 7 times of biaxial stretching at the same time. At this time, simultaneous biaxial tenter frame to the set temperature of the 123 °C. Then introduced into the extracting groove, fully impregnated in methylene chloride, to remove the liquid paraffin is extracted. After drying of methylene chloride. And then into the transverse tentering machine to horizontal stretched 1.4 times the rear, according to the final outlet reach 1.2 times are relaxed, the implementation of the winding. Cross expandering Department to the setting temperature of 120 °C, relaxation department to the set temperature of 125 °C. The characteristics of the resulting porous film is shown in table 2.

[Table 1]

[Table 2]

From table 1 and 2 can be the result of reading the following content.

(1) from the embodiment-1-1 1-4 and comparative example 1-1, 1-2 can be known contrast, contains a primary particle size of inorganic particles in a specific range and has a laminated structure of this embodiment is 1 laminated divider with a primary particle size from the above-mentioned specific range or not the embodiment of the stacked structure compared with the embodiment of the, heat resistance in good balance, cycle characteristics and closed cell characteristic.

(2) from the embodiment 1-1 and embodiment 1-5-1-7 result can be known, to take into account heat resistance, cycle characteristics and closed cell characteristic effect is concerned, in a wide range in the inorganic particle content can be realized.

(3) embodiment from 1-1 and embodiment 1-8.1-9 can be known the result of, to take into account heat resistance, cycle characteristics and closed cell characteristic effect is concerned, in the broad PP content can be realized.

(4) from the embodiment 1-1 and embodiment 1-10-1-13 result can be known, to take into account heat resistance, cycle characteristics and closed cell characteristic effect is concerned, the layer thickness of the various kinds, in a variety of layers can be realized.

[The embodiment 2]

Furthermore, comparative example cited more specific embodiments to explain the embodiment 2, however, the embodiment 2 as long as not exceeding its thrust is not limited to the following embodiment. To note, in the embodiment of the method is determined by using the following physical properties.

(1) (Mv) nien average molecular weight

Under ASTM-D4020, in the solvent in the calculation of decahydronaphthalene 135 °C lower intrinsic viscosity.

Mv of polyethylene obtained by using the following formula.

[η] =0.00068 ×Mv^0.67

Mv of polypropylene is obtained using the following formula.

[η] =1.10 ×Mv^0.80

Layer using Mv formula of polyethylene.

(2) film thickness (µm)

With micro- thickness gauge (KBM dongyang fine mechanism models) at room temperature is measured at 23 ±2 °C.

(3) porosity (%)

Cut from the microporous membrane is 10 cm × 10 cm square sample, calculate its volume (cm³) and quality (g), and a film density by these values (g/cm³) calculated using the following formula.

Porosity (%) = (volume-the quality/density of the mixed composition) × 100/volume

To note, the density of the mixed composition by the use of polyolefin resin and the inorganic particles for each of the density obtained by mixing ratio and the value of the calculated.

(4) air permeability (sec/100cc)

Based on use JISP-8117 of permeability ideagurley type determining (Toyo fine mechanisms).

(5) puncture strength (g)

Using KATOTECHCO., LTD. Systems, TM KES-G5 portable compressed tester, the front end of the needle with a radius of curvature of 0.5 mm, the puncture-speed 2 mm/sec under the condition of a puncture test, the maximum puncture load as the puncture strength (g).

(6) electrolyte including soaks the nature

Using as the electrolyte 1mol/L solution of lithium phosphate hexafluoride (solvent: dimethyl carbonate carbonate), the electrolyte within the glove box instillment to micro porous film. The 30 seconds after the droplet and the electrolyte with the contact surface of the porous film is 80% or more is judged to be a good including soaks the nature (O), will be less than 80% for judging the condition of inadequate including soaks the nature (×).

(7) cycle characteristics (% / 100 times)

Modulation by the ethylene carbonate (EC): dimethyl carbonate (MEC) =1 Kabool ester: 2 (weight ratio) the solvent is added in a LiPF₆ 1M of the electrolyte, making negative electrode using a carbon electrode, positive electrode using LiCoO₂, use as a measurement sample separating part of the lithium ion battery of the microporous membrane. The battery is charged to the 4.2V later, so that its discharge, in 25 °C repeated operation under 100 cycle test of, after the cycle test study changes in the battery capacity.

(8) the obturator temperature (°C), short-circuit temperature (°C)

Figure 1 (A) of the obturator temperature measuring device that the outline of the Figure. 1 for the porous membrane (as determine the target's laminated divider), 2A and 2B the thickness 10 µm the nickel foil, 3A and 3B as the glass sheet. 4 is a resistance measuring device (an Tengelectrical system LCRmeter " AG-4311 the [...] (trade mark)), and the nickel foil 2A, 2B is connected. 5 is a thermoelectric couple, and the thermometer 6 is connected. 7 as a data collector, and resistance device 4 and thermometer 6 is connected. 8 for the dry oven, to heat the microporous film.

When to explain in more detail, as shown in Figure 1 (B) illustrated, the nickel foil 2A overlap on the porous membrane 1, used in the longitudinal direction "Teflon (registered trademark)" with (oblique line part of the graph) is fixed on the nickel foil 2A the upper. In the microporous membrane 1 as electrolyte impregnated in 1mol/L of boron fluorizating lithium solution (solvent: propylene carbonate/ethylene carbonate / γ-butyrolactone = 1/1/2). As shown in Figure 1 (C) illustrated, the nickel foil 2B laminate "Teflon (registered trademark)" with (oblique line part of the graph), the foil 2B reserved in the central part 15 mm × 10 mm of the window portion of the shielding.

In order to grasp the microporous membrane 1 form overlapping foil 2A and nickel foil 2B, and then utilize glass plate 3A, 3B from the nickel foil 2A and nickel foil 2B clamping the two sides of the 2 pieces of nickel foil. At this moment, foil 2B with the window part of the porous membrane 1 in a relative position.

2 sheets of glass plate by using a commercial double-clamp for clamping and fixing. Thermocouple 5 with "Teflon (registered trademark)" belt is fixed on the glass plate.

Use of this kind of device continuously measuring temperature and resistance. To note, the temperature from 25 °C to 2 °C/min speed heating to 200 °C, resistance to 1V, 1kHz exchange of measured under the condition of. The obturator temperature defined as the resistance value of the porous film to reach 10³ Ω the temperature of the; closed the membrane, after hole to the blocking state, is lower than the resistance again 10³ Ω as a short circuit of the temperature of the temperature.

(9) in the polypropylene-ethylene copolymer containing ethylene

Based on the report of the who Kakugo (Macromolecules1982, 15, 1150-1152) under the following conditions by the measuring 13C-NMR spectrum obtained. In 10 mm the test tube of approximately 200 mg of a propylene-ethylene block copolymer is dissolved in a 3 ml of O-dichlorobenzene modulation sample, measured under the following conditions.

Measuring temperature: 135 °C

Pulse return time: 10 seconds

Pulse amplitude: 45°

Cumulative number: 2500 times

(10) of inorganic filling material of plasticizer oil absorption

Using FRONTEXS410 plasticizer oil absorption sokuteiki the following determination. Inorganic filling material in 5g, while milling a-side drop [...] (paraffin oil). Rise in mixing torque is obtained, then the maximum torque is reduced to 70% of (ml) when plasticizer addition, by the value and the inorganic filling material weight (g) is calculated using the following formula.

Plasticizer oil absorption (ml/100g) = plasticizer addition of inorganic filling material weight × 100/

[Embodiment 2-1]

matches mixes sticks average molecular weight of 40 million polypropylene (melting point 163 °C) 21.2 parts by mass (78% quality), nien average molecular weight of 25 million ethylene content and 3 mass % of the propylene-ethylene copolymer (melting point 160 °C) 0.4 parts by mass of the (2 mass %), nien average molecular weight of 25 million high-density polyethylene (melting point 137 °C) 5.4 parts by mass (20 mass %), double as a nucleating agent (p- ethyl Asia phenmethyl) sorbitol 0.3 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, paraffin oil (engelm tsuen petroleum Institute systems: P350P) 63 parts by mass (70% quality), modulation raw materials. The use of batch melt mixing machine (society system dongyang of the stool: [...]) in 200 °C, mixing the mixture under 50rpm 10 minutes. Using 200 °C of the heating and press in order to 5 MPa the resulting kneaded product while forming, heat treatment for 3 minutes, the control for the 25 °C in the water-cooling and compressor 5 MPa lower cooling, the thickness of the obtained 500 µm the sheet material. At the same time the 2 shaft stretcher (dongyang precision instrument society system) in 120 °C stretched to the 4 × 4 times, after removal of the dichloromethane is used for extracting the paraffin oil drying it. The resulting microporous polyethylene film physical property shown in table 3.

[Embodiment 2-2-2-5, comparative example 2-1-2-3]

In addition to table 3 other than the conditions shown in the, embodiment and 2-1 similarly obtain polyethylene microporous membrane. The resulting microporous polyethylene film physical property shown in table 3.

To note, as an inorganic filling material of silicon dioxide of the oil absorption volume is 200 ml/100 g.

[Embodiment 2-6]

The use of mixer the agitation sticks average molecular weight of 40 million polypropylene (melting point 163 °C) 31.4 parts by mass, having a viscosity average molecular weight 25 million ethylene content and 3 mass % of the propylene-ethylene copolymer (melting point 160 °C) 0.6 parts by mass, having a viscosity average molecular weight 25 million high-density polyethylene (melting point 137 °C) 8.0 parts by mass, the double as a nucleating agent (p- ethyl Asia phenmethyl) sorbitol 0.3 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, liquid paraffin as a plasticizer (engelm tsuen petroleum Institute systems: P350P) 9.6 parts by mass, the modulation with the surface layer of the raw material.

the mix sticks average molecular weight of 25 million of high-density polyethylene of 14.25 parts by mass, having a viscosity average molecular weight 70 million of high-density polyethylene of 14.25 parts by mass, having a viscosity average molecular weight 40 million polypropylene 1.5 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, the raw materials of the modulation of the intermediate layer.

The mixture lie between 2 taiwan caliber 25 mm, L/D=48 machine feeding engine into the double-shaft extruder. In the surface layer of the raw material, the liquid paraffin 65 parts by mass of a side feed to the extruder, in the raw material of the middle layer, the liquid paraffin 70 parts by mass of a side feed to the extruder, in accordance with two surface layer, respectively of the intermediate layer per hour the extruder to 4 kg, adjusted 16 kg, in 200 °C, 200rpm after milling is conducted under conditions of, in 220 °C from the mounting under the condition of the front the extrusion can be co-extruded (two types of three-layer) extruded from the T die. Immediately the control of surface temperature to 70 °C in the roller, and then for the control of surface temperature 25 °C cooling of rolls, forming thickness 1.4 mm sheet material. The use of simultaneous biaxial stretching machine 123 °C the sheet material under the condition of tensile to 7 × 7 after the times, is impregnated in methylene chloride, to remove the liquid paraffin drying after the extraction, the use of the tenter stretcher 119 °C stretching in the transverse direction under the conditions of 1.4 times. Later, in 124 °C in the width direction of the drawing sheet laidback 21%, heat treatment is performed, the two layers having a surface layer of the same composition, the intermediate layer is a different composition of the two types of three-layer structure of the microporous membrane. The resulting microporous membrane bussei shown in table 4.

[Embodiment 2-7-2-15, comparative example 2-4-2-5]

In addition to the table 4 with the conditions shown in embodiment 2-6 similarly obtain polyethylene microporous membrane. The resulting microporous polyethylene film physical property shown in table 4.

[Embodiment 2-16]

The polyolefin section 1 having a viscosity average molecular weight materials are micro porous level 40 million polypropylene (melting point 163 °C) 24.4 parts by mass, having a viscosity average molecular weight 25 million ethylene content and 3 mass % of the propylene-ethylene copolymer (melting point 160 °C) 1.2 parts by mass, having a viscosity average molecular weight 25 million high-density polyethylene (melting point 137 °C) 5.9 parts by mass, having a viscosity average molecular weight 1000 polyethylene (melting point 120 °C) 0.5 parts by weight, an average primary particle size 15 nm silicon dioxide 8 parts by mass, in addition, with the embodiment 2-6 similarly obtained with two kinds of three-layer structure of the microporous membrane.

The resulting laminated divider closed cell characteristic is excellent.

To note, as an inorganic filling material of silicon dioxide of the oil absorption volume is 200 ml/100 g.

[Table 3]

[Table 4]

From table 3 and 4 can be known the result of, the embodiment 2 is suitable to be used as the microporous film can improve the cycle characteristics of the storage equipment of the divider.

[The embodiment 3]

Furthermore, comparative example cited more specific embodiments to explain the embodiment 3, but this embodiment is 3 as long as not exceeding its thrust is not limited to the following embodiment. To note, in the embodiment of the method is determined by using the following physical properties.

Having a viscosity average molecular weight (Mv), film thickness, porosity, permeability, puncture strength, inorganic filling material plasticizer with the oil absorption of the embodiment 2 is the same as the determining method of the embodiment.

(1) melting point (°C)

Using Shimadzu seisakusho society system DSC60 to be measured. Collecting 3 mg of the sample as a measurement sample. The diameter of the 5 mm of the aluminum oxide on the sample plate oven, cover for clamping the cover plate is fixed on the alumina template sample. In the nitrogen environment, temperature rise speed 10 °C/min from 30 °C start determination to 200 °C, melting heat absorption curve is obtained (meltingendothermiccurve). To the resulting melt endothermic curve, in 85 °C -175 ° C set within the range of straight line baseline, the baseline and melting by the straight line surrounded by the heating curve calculation of heat energy the area of a part, for each unit the conversion of the sample quality, computing fusion heat. Furthermore, similarly the fusion heat in melting curve Δ H and the minimum value temperature as that of the melting point is measured.

(2) particle size of the inorganic particles (nm) a

Divider from stratifying collecting measurement object, using the scanning type electron microscope to 30000 times observed, in the vertical 3.0 µm, transverse 3.0 µm that the field of vision of the inorganic particle size. Explanation, "a particle diameter" refers to separate each particle dispersed in the substrate under the state of the particle size of, or even generating agglutionation, wherein the form of the most a small particle size. Furthermore, the measured value of the 10 points average value of the observed value.

(3) cycle characteristics (% / 100 times)

A. Production of positive electrode

As a positive electrode active material of the lithium-cobalt composite oxide (LiCoO₂) 92.2 quality %, as the conductive material of the 2.3% quality of flake graphite and acetylene black, polyvinylidene fluoride (PVDF) 3.2 as the bond quality % dispersed in N-methyl pyrrolidone (NMP) modulate the slurry. The slurry coating through molding as a positive electrode current collector is coated on the thick 20 µm on one side of the aluminum foil, the 130 °C drying under 3 minutes later, using press compression forming. At this moment, positive electrode active material for the coating 250g/m², active material bulk density is 3.00g/cm³.

B. Preparation of a negative electrode

The active material of the negative electrode as artificial graphite 96.9% quality, as the adhesive of the ammonium salt of carboxymethyl cellulose 1.4 mass %, and styrene-butadiene copolymer latex 1.7% dispersion in the quality of refined water modulate the slurry. Utilizing the embossing coating the slurry is coated on the thick as the cathode current collector 12 µm on one side of the copper foil, the 120 °C drying under 3 minutes later, using press compression forming. At this moment, the negative electrode active material for the coating 106g/m², active material bulk density is 1.35g/cm³.

C. The modulation of the non-aqueous electrolyte

In ethylene carbonate: methyl ethyl carbonate = 1:2 (volume ratio) in the mixed solvent of solute compounding LiPF₆ to make its concentration 1.0mol/L, for modulation.

D. Battery assembly

The spacers shear cut Circular, cut into the positive electrode and negative electrode Round, in accordance with a positive electrode and a negative electrode of the active substance, to cathode, spacer, anode superposed in order, of the stainless steel cover is installed in the metal container. The insulating container and lid, the copper foil is connected with the negative electrode container, cover and the positive electrode is connected with aluminum foil. In this container into said non-aqueous electrolyte for sealing. Placed at room temperature 1 future, in 25 °C environment to under 2.0mA (0.33C) is charged to the voltage of the battery current value of 4.2V, after the 4.2V, from 2.0mA begin to narrow the current value, by the same method to process a total of 8 hours, the initial charging of the battery. Furthermore, in order to 2.0mA (0.33C) the current value of the battery voltage discharge to 3.0 V.

E. Capacity maintenance ratio (%)

The charging and discharging in the 60 °C the implementation environment 100 times of circulation. Charging to 6.0mA (1.0C) is charged to the voltage of the battery current value of 4.2V, maintain the 4.2V, from 6.0mA begin to narrow the current value, charging by the method a total of 3 hours. Discharge to 6.0mA (1.0C) the current value of the battery voltage discharge to 3.0 V. By section 100 and the discharge capacity of the secondary cycle of the section 1 the discharge capacity of the secondary cycle of the computational capacity maintenance ratio. Capacity maintenance ratio is very high, the cycle characteristics of the evaluation has good.

(4) high-temperature storage characteristics evaluation (%)

The above-mentioned if the battery assembling simple a-d 25 °C environment, to 3mA (about 0.5C) is charged to the voltage of the battery current value of 4.2V, after reaching the 4.2V, from 3mA begin to narrow the current value, by the same method to process a total of 6 hours of charging. Furthermore, in order to 3mA the current value of the battery voltage discharge to 3.0 V.

Furthermore, in the 25 °C environment, to 6mA (about 1.0C) is charged to the voltage of the battery current value of 4.2V, maintain the 4.2V, from 6mA begin to narrow the current value, by the same method to process a total of 3 hours of charging. Furthermore, in order to 6mA the current value of the battery voltage discharge to 3.0 V. The discharge capacity at this moment as A (mAh).

Furthermore, in the 25 °C environment, to 6mA (about 1.0C) is charged to the voltage of the battery current value of 4.2V, maintain the 4.2V, from 6mA begin to narrow the current value, by the same method to process a total of 3 hours of charging. To the battery is in the charging state 60 °C maintain under the environment 7 days. In taking the battery after 25 °C environment to under 6mA the current value of the battery voltage discharge to 3.0 V. Furthermore, in the 25 °C environment to under 6mA (about 1.0C) is charged to the voltage of the battery current value of 4.2V, after reaching the 4.2V, from 6mA begin to narrow the current value, by the same method to process a total of 3 hours of charging. Furthermore, in order to 6mA the current value of the battery voltage discharge to 3.0 V. The discharge capacity at this moment as B (mAh). The ratio of the the B A, calculate the capacity maintenance ratio, as a high-temperature storage characteristics.

(5) the obturator temperature (°C), short-circuit temperature (°C)

Figure 1 (A) of the obturator temperature measuring device that the outline of the Figure. 1 for the porous membrane (as determine the target's laminated divider), 2A and 2B the thickness 10 µm the nickel foil, 3A and 3B as the glass sheet. 4 is a resistance measuring device (an Tengelectrical system LCRmeter " AG-4311 the [...] (trade mark)), and the nickel foil 2A, 2B is connected. 5 is a thermoelectric couple, and the thermometer 6 is connected. 7 as a data collector, and resistance device 4 and thermometer 6 is connected. 8 for the dry oven, to heat the microporous film.

When to explain in more detail, as shown in Figure 1 (B) illustrated, the nickel foil 2A overlap on the porous membrane 1, used in the longitudinal direction "Teflon (registered trademark)" with (oblique line part of the graph) is fixed on the nickel foil 2A the upper. In the microporous membrane 1 as electrolyte impregnated in 1mol/L of boron fluorizating lithium solution (solvent: propylene carbonate/ethylene carbonate / γ-butyrolactone = 1/1/2). As shown in Figure 1 (C) illustrated, the nickel foil 2B laminate "Teflon (registered trademark)" with (oblique line part of the graph), the foil 2B reserved in the central part 15 mm × 10 mm of the window portion of the shielding.

In order to grasp the microporous membrane 1 form overlapping foil 2A and nickel foil 2B, and then utilize glass plate 3A, 3B from the nickel foil 2A and nickel foil 2B two sides 2 a nickel foil. At this moment, foil 2B with the window part of the porous membrane 1 in a relative position.

2 sheets of glass plate by using a commercial double-clamp for clamping and fixing. Thermocouple 5 with "Teflon (registered trademark)" belt is fixed on the glass plate.

Use of this kind of device continuously measuring temperature and resistance. To note, the temperature from 25 °C to 2 °C/min speed heating to 200 °C, resistance to 1V, 1kHz exchange of measured under the condition of. Closed the resistance value of the temperature of the positioning for the microporous membrane 10³ Ω the temperature of the, closure of the film, after the hole to the blocking state, is lower than the resistance again 10³ Ω as a short circuit of the temperature of the temperature.

(6) content of the copolymerized monomer

In the propylene copolymer copolymerized monomer (ethylene and α-olefin) content thereof, according to the determination of the use of the report C.J.Carman 13C-NMR method method (Macromolecules, 10,537 (1977) to.

(7) average pore diameter

Known capillary internal fluid complying fluid is less than the mean free path of the capillary tube diameter for the Poiseuille flow, vertical stroke woods class capillary tube diameter is greater than the. Here, when the assumptions in air permeability of the air flow determining compliance vertical stroke woods class , at room temperature the water in the measuring water leakiness flow complying Poiseuille flow, the average pore diameter d (m) and hole a tortuosity factor (no because inferior value) τ can be by the air of Rgas through the speed constant, constant Rliq through the speed of the water, the water viscosity η (Pa ·sec), standard pressure Ps (101325 Pa), porosity ε (the value), the film thickness L (m), ν (m/sec) molecular velocity of the gas is obtained using the following formula;

D=2 subsidence (Rliq/Rgas) (16 subsidence/3) (1/Ps)

Here, the air permeability (sec) Rgas obtained using the following formula;

Rgas (m³ / (m² ·sec·Pa)) =0.0001/air permeability/0.0006424 / (0.01276 × 101325)

Furthermore, by Rliq water leakiness (cm³ / (cm² ·sec·Pa)) obtained using the following formula

Rliq (m³/m² ·sec·Pa) = water leakiness /100 million/0.0001

The above-mentioned type in the following measuring permeable degrees;

The diameter of 42 mm stainless steel passes the fluid pond pre-soaked in ethanol is placed in the microporous film, the film of water after washing with ethanol, to about 50000 Pa the pressure difference of the water through the, by 120 seconds is completely of (cm³) time calculating unit, unit pressure, the unit area of the completely, as the water leakiness (cm³ / (cm² ·sec·Pa)).

And then, the gas constant R (the 8.314J/mol  K), absolute temperature T (K), PI π, an average molecular weight of the gas M (=2.896 × 10^-2) (kg/mol) ν is obtained using the following formula;

ν² = 8RT / π M

[Embodiment 3-1]

the mix sticks average molecular weight of 40 million polypropylene (melting point 163 °C) 50.4 parts by mass, having a viscosity average molecular weight 25 million ethylene content and 5% of the quality heat of fusion 70J/g propylene-ethylene random copolymer (melting point 140 °C) 12.6 parts by mass, the double as a nucleating agent (p- ethyl Asia phenmethyl) sorbitol 0.3 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, paraffin oil (engelm tsuen petroleum Institute systems: P350P, plasticizer density 0.868g/cm³) 63 parts by mass, modulation raw materials. The use of batch melt mixing machine (society system dongyang of the stool: [...]) in 200 °C subsidence 50rpm mixing the mixture 10 minutes. Using 200 °C heating and pressurizing of the lower to 5 MPa the resulting kneaded product while forming, heat treatment for 3 minutes, the control for the 25 °C the water-cooling and compressor cooling to 5 MPa, the thickness of the obtained 500 µm the sheet material. At the same time the 2 shaft stretcher (dongyang precision instrument society system) in 125 °C the lower will be its stretched to 5 × 5 times, after removal of the dichloromethane is used for extracting the paraffin oil drying it. The resulting microporous polyethylene film physical property shown in table 5.

[Embodiment 3-2-3-8, comparative example 3-1-3-4]

In addition to table 5 other than the conditions shown, and embodiment 3-1 similarly obtain polyethylene microporous membrane. The resulting microporous polyethylene film physical property shown in table 5.

To note, as an inorganic filling material of silicon dioxide of the oil absorption volume is 200 ml/100 g.

Furthermore, the use of high-density polyethylene having a viscosity average molecular weight of 25 million, melting point of 137 °C.

[Embodiment 3-9]

As the surface layer of the raw material, the mix sticks average molecular weight of 40 million polypropylene (melting point 163 °C) 50.4 parts by mass, having a viscosity average molecular weight 25 million and ethylene content of 5 mass % of a propylene/ethylene random copolymer (melting point 140 °C, heat of fusion 70J/g) 12.6 parts by mass, the double as a nucleating agent (p- ethyl Asia phenmethyl) sorbitol 0.3 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, the modulation of the raw materials.

As the intermediate layer of raw materials, mixed 14.25 quality the share sticks average molecular weight of 25 million and melting point 137 °C high density polyethylene 1, 14.25 quality the share sticks average molecular weight of 70 million and melting point 137 °C high density polyethylene 2, nien average molecular weight of 40 million and melting point 163 °C polypropylene 1.5 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, modulation raw materials.

Mixture lie between 2 taiwan caliber 25 mm, L/D=48 machine feeding engine into the double-shaft extruder. In the surface layer, the liquid paraffin 63 parts by mass is fed to the extruder side, in the intermediate layer, the liquid paraffin 68 parts by mass of a side feed to the extruder, in accordance with two surface layer, respectively of the intermediate layer per hour the extruder to 4 kg, adjusted 16 kg, in 200 °C, 200rpm after milling is conducted under conditions of, in 220 °C from the mounting under the condition of the front the extrusion can be co-extruded (two types of three-layer) extruded from the T die. Immediately the control of surface temperature to 90 °C in the roller, and then for the control of surface temperature 25 °C cooling of rolls, forming thickness 1.4 mm sheet material. The use of simultaneous biaxial stretching machine 125 °C the sheet material under the condition of tensile to 7 × 7 after the times, is impregnated in methylene chloride, to remove the liquid paraffin drying after the extraction, the use of the tenter stretcher 120 °C stretching in the transverse direction under the condition of 1.5 times. Later, in 125 °C in the width direction of the drawing sheet laidback 13%, heat treatment is performed, the two layers having a surface layer of the same composition, the intermediate layer is a different composition of the two types of three-layer structure of the microporous membrane. The resulting microporous membrane bussei shown in table 6.

[Embodiment 3-10-3-21, comparative example 3-5-3-8]

In addition to table 6 other than the conditions shown, and embodiment 3-9 similarly obtain polyethylene microporous membrane. The resulting microporous polyethylene film physical property shown in table 6.

[Embodiment 3-22]

In addition to the polyolefin section 1 having a viscosity average molecular weight materials are micro porous level 40 million polypropylene (melting point 163 °C) 24.4 parts by mass, having a viscosity average molecular weight 25 million and ethylene content of 5 mass % of the propylene-ethylene copolymer (melting point 160 °C) 1.2 parts by mass, having a viscosity average molecular weight 25 million high-density polyethylene (melting point 137 °C) 5.9 parts by mass, having a viscosity average molecular weight 1000 polyethylene (melting point 120 °C) 0.5 parts by weight, an average primary particle size 15 nm silicon dioxide 8 parts by mass of the outside, and embodiment 3-9 similarly obtained with two kinds of three-layer structure of the microporous membrane.

The resulting laminated divider closed cell characteristic is excellent.

To note, as an inorganic filling material of silicon dioxide of the oil absorption volume is 200 ml/100 g.

[Table 5]

[Table 6]

From table 5 and 6 can be known the result of, the embodiment 3 is suitable for being used as the microporous film can improve the cycle characteristics of the storage equipment of the divider.

[The embodiment 4]

Furthermore, comparative example embodiments cited more specifically illustrate the embodiment 4, however, this embodiment is 4 as long as not exceeding its thrust is not limited to the following embodiment. To note, in the embodiment of the method is determined by using the following physical properties.

Having a viscosity average molecular weight (Mv), melting point, a primary particle size of the inorganic particles, the film thickness, porosity, permeability, puncture strength, cycle characteristics, high-temperature preservation characteristic evaluation, the obturator temperature, short-circuit temperature, the content of the monomer is copolymerized, inorganic filling material plasticizer with the oil absorption of the embodiments 2 and 3 of the embodiment of the method is the same.

[Embodiment 4-1]

the mix sticks average molecular weight of 40 million polypropylene (melting point 163 °C) 12.9 parts by mass, having a viscosity average molecular weight 25 million and ethylene content of 5 mass % of a propylene/ethylene random copolymer (melting point 140 °C) 5.7 parts by mass, having a viscosity average molecular weight 25 million high-density polyethylene (melting point 137 °C) 8.0 parts by mass, silicon dioxide (oil absorption 200 ml/100g) 8 parts by mass, the double as a nucleating agent (p- ethyl Asia phenmethyl) sorbitol 0.3 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, paraffin oil (engelm tsuen petroleum Institute systems: P350P, plasticizer density 0.868g/cm³) 62 parts by mass, modulation raw materials. The use of batch melt mixing machine (society system dongyang of the stool: [...]) in 200 °C subsidence 50rpm mixing the mixture 10 minutes. Using 200 °C heating and pressurizing of the lower to 5 MPa the resulting kneaded product while forming, heat treatment for 3 minutes, the control for the 25 °C in the water-cooling and compressor 5 MPa lower cooling, the thickness of the obtained 500 µm the sheet material. At the same time the 2 shaft stretcher (dongyang precision instrument society system) in 125 °C the lower will be its stretched to 5 × 5 times, after removal of the dichloromethane is used for extracting the paraffin oil drying it. The resulting microporous polyethylene film physical property shown in table 7.

[Embodiment 4-2-4-6, comparative example 4-1-4-3]

In addition to table 7 conditions of shown, and embodiment 4-1 similarly obtain polyethylene microporous membrane. The resulting microporous polyethylene film physical property shown in table 7.

[Embodiment 4-7]

As the surface layer of the raw materials, using mixer the agitation sticks average molecular weight of 40 million polypropylene (melting point 163 °C) 16.3 parts by mass, having a viscosity average molecular weight 25 million and ethylene content of 5 mass % of a propylene/ethylene random copolymer (melting point 140 °C, heat of fusion 70J/g) 7.2 parts by mass, having a viscosity average molecular weight 25 million high-density polyethylene (melting point 137 °C) 10.1 parts by mass, silicon dioxide (oil absorption 200 ml/100g) 14.4 parts by mass, the double as a nucleating agent (p- ethyl Asia phenmethyl) sorbitol 0.3 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, liquid paraffin as a plasticizer (engelm tsuen petroleum Institute systems: P350P) 17.3 parts by mass, modulation raw materials.

As the intermediate layer of raw materials, mixed 14.25 quality the share sticks average molecular weight of 25 million and melting point 137 °C high density polyethylene 1, 14.25 quality the share sticks average molecular weight of 70 million and melting point 137 °C high density polyethylene 2, nien average molecular weight of 40 million and melting point 163 °C polypropylene 1.5 parts by mass, as the antioxidant of the four-[ methylene-(3 the [...] , 5 the [...] -di-tert-butyl -4 the [...] -hydroxy-phenyl) propionate] methane 0.2 parts by mass, modulation raw materials.

The mixture lie between 2 taiwan caliber 25 mm, L/D=48 machine feeding engine into the double-shaft extruder. In the surface layer, the liquid paraffin 60 parts by mass of a side feed to the extruder, in the intermediate layer, the liquid paraffin 70 parts by mass of a side feed to the extruder, in accordance with two surface layer, respectively of the intermediate layer per hour the extruder to 4 kg, adjusted 16 kg, in 200 °C, 200rpm after milling is conducted under conditions of, in 220 °C from the mounting under the condition of the front the extrusion can be co-extruded (two types of three-layer) extruded from the T die. Immediately the control of surface temperature to 70 °C in the roller, and then for the control of surface temperature 25 °C cooling of rolls, forming thickness 1.4 mm sheet material. The use of simultaneous biaxial stretching machine 125 °C the sheet material under the condition of tensile to 7 × 7 after the times, is impregnated in methylene chloride, to remove the liquid paraffin drying after the extraction, the use of the tenter stretcher 125 °C stretching in the transverse direction under the condition of 1.5 times. Later, in the 132 °C in the width direction of the drawing sheet laidback 21%, heat treatment is performed, the two layers having a surface layer of the same composition, the intermediate layer is a different composition of the two types of three-layer structure of the microporous membrane. The resulting microporous membrane bussei shown in table 8.

[Embodiment 4-8-4-17, comparative example 4-4-4-6]

In addition to table 8 other than the conditions shown, and embodiment 4-7 similarly obtain polyethylene microporous membrane. The resulting microporous polyethylene film physical property shown in table 8.

[Embodiment 4-18]

In addition to the polyolefin section 1 having a viscosity average molecular weight materials are micro porous level 40 million polypropylene (melting point 163 °C) 24.4 parts by mass, having a viscosity average molecular weight 25 million and ethylene content of 5 mass % of the propylene-ethylene copolymer (melting point 160 °C) 1.2 parts by mass, having a viscosity average molecular weight 25 million high-density polyethylene (melting point 137 °C) 5.9 parts by mass, having a viscosity average molecular weight 1000 polyethylene (melting point 120 °C) 0.5 parts by weight, an average primary particle size 15 nm silicon dioxide 8 parts by mass of the outside, and embodiment 4-7 similarly obtained with two kinds of three-layer structure of the microporous membrane.

The resulting laminated divider closed cell characteristic is excellent.

[Table 7]

[Table 8]

From table 7, 8 can know the result of, the embodiment 4 is suitable to be used as the microporous film can improve the cycle characteristics of the storage equipment of the divider.

The application for Patent of Japan, based on 9 March 2009 to the office of the Japanese Patent application application (extra wish to 2009-054795), the office to 17 March 2009 applications for Patent of Japan, the Japanese Patent application (extra wish to 2009-064533), the office to 10 December 2009 applications for Patent of Japan, the Japanese Patent application (extra wish to 2009-280486), the office to 10 December 2009 applications for Patent of Japan, the Japanese Patent application (extra wish to 2009-280488), the office to 3 February 2010 applications for Patent of Japan, the Japanese Patent application (extra wish to 2010-021859) and Japan Patent office 3 February 2010 to the Japanese Patent application application (extra wish to 2010-022481), its content as a reference for the integration.

Industrial availability

The present invention provides heat balance high dimension , cycle characteristics of the spacers and closed cell characteristic. The separating parts, particularly as a separator for lithium ion battery has the industrial practicability.

Furthermore, the invention also provides suitable as a can improve the cycle characteristics of the storage equipment of the polyolefin microporous membrane of the separator.