WO2011096048A1

WO2011096048A1 - Porous film capable of attaining oxidation treatment of carbon monoxide, and use thereof

Info

Publication number: WO2011096048A1
Application number: PCT/JP2010/051445
Authority: WO
Inventors: 瀬田　寧
Original assignee: リケンテクノス株式会社
Priority date: 2010-02-02
Filing date: 2010-02-02
Publication date: 2011-08-11
Also published as: JP5693474B2; JPWO2011096048A1

Abstract

Provided is a porous film which can function both as a carbon monoxide absorber and as a separator for a battery. A porous film made of a resin composition which comprises (A) 100 parts by mass of a resin, (B) 1 to 300 parts by mass of a catalyst for the oxidation of carbon monoxide, and (C) 1 to 300 parts by mass of a carbon dioxide-adsorbing substance.

Description

Porous film capable of oxidizing carbon monoxide and use thereof

The present invention relates to a porous film suitable for treatment of carbon monoxide generated in a container in which a power storage element is enclosed in a power storage device such as a non-aqueous electrolyte secondary battery or an electric double layer capacitor. In particular, the present invention relates to a porous film that can be suitably used as a separator for a nonaqueous electrolyte secondary battery.

In recent years, non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries and electric storage devices such as electric double layer capacitors have been attracting attention in a wide range of mobile devices such as mobile phones, office automation equipment, electric vehicles and hybrid vehicles. Use is expanding.

Non-aqueous electrolyte secondary batteries and electric double layer capacitors have a significant decrease in performance when moisture is present in the container in which the electricity storage element is sealed, and thus the life of the battery is reduced. It is enclosed in a container such as an aluminum laminate film.

However, non-aqueous electrolyte secondary batteries and electric double layer capacitors have the property that carbon monoxide gas is likely to be generated in the container in which the electricity storage element is enclosed, and as a result, the life is shortened due to deformation and rupture of the container. There is a problem of inviting.

In order to prevent deformation and rupture of the container due to the generation of carbon monoxide gas, it is widely practiced to provide a gas release valve on the metal can, but the release of the gas leads to the ingress of moisture from the outside air, and the service life is reduced. Inevitable. Moreover, it is difficult to provide a gas release valve in the laminated film exterior type.

Several substances that directly absorb and adsorb carbon monoxide gas are known, but they can only absorb a very small amount of carbon monoxide per unit amount and absorb and adsorb a sufficient amount of carbon monoxide. Not suitable for the purpose.

On the other hand, as a method for removing carbon monoxide in a gas, a method using a catalyst containing a gold nanoparticle catalyst as a carbon monoxide oxidation catalyst and an alkaline porous material as a carbon dioxide removing agent (for example, Patent Documents) 1) and a method using a catalyst containing a gold nanoparticle catalyst as a carbon monoxide oxidation catalyst and a zeolite as a carbon dioxide and water removal agent (for example, Patent Document 2) is known. These methods oxidize carbon monoxide gas to carbon dioxide gas and remove the resulting carbon dioxide gas with a carbon dioxide adsorbent, which is less expensive than removing carbon monoxide gas directly. The oxidation of carbon monoxide gas requires the presence of gaseous oxygen.

The nonaqueous electrolyte secondary battery and the electric double layer capacitor do not have a supply source of gaseous oxygen to the inside of the container in which the electricity storage element is enclosed. This is because, for the purpose of enclosing more power storage elements in the container, there is no space in the production stage where gaseous air occupies, and since the container is sealed, it is sealed from the outside. This is because there is virtually no supply of gaseous oxygen.

If carbon monoxide can be oxidized to carbon dioxide in the absence of gaseous oxygen, the carbon monoxide gas generated in the container is absorbed by adsorbing the carbon dioxide generated by the oxidation in the container. It can be processed sufficiently and inexpensively in the container. This is useful for preventing a container in which a power storage element in a power storage device such as a non-aqueous electrolyte secondary battery or an electric double layer capacitor is sealed from being deformed or destroyed by the generation of carbon monoxide gas. As a result, it is advantageous for extending the life of the electricity storage device.

In view of the above circumstances, the present inventor provides a method capable of sufficiently and inexpensively treating carbon monoxide generated in a closed container containing a substance that substantially does not contain gaseous oxygen and generates carbon monoxide. As a result of earnest research for the purpose of achieving the above, a molded article comprising a resin composition in which the oxidation of carbon monoxide generated in the closed container to carbon dioxide in the container is incorporated with a carbon monoxide oxidation catalyst in the resin That the carbon monoxide can be satisfactorily treated (absorbed) by further including a carbon dioxide adsorbing substance in the resin composition. (Japanese Patent Application Nos. 2009-023790 and 2009-023888).

However, when the molded body is used as a carbon monoxide absorbent in a non-aqueous electrolyte secondary battery, there is room for further improvement in the following points. That is, carbon monoxide is particularly generated between the positive electrode and the negative electrode of the nonaqueous electrolyte secondary battery, and even a small bubble increases the internal resistance of the battery and lowers the performance. In addition, with the recent miniaturization of electronic devices, non-aqueous electrolyte secondary batteries are required to be reduced in size and capacity, and there is also a problem of arrangement space.

On the other hand, a separator is disposed between the positive electrode and the negative electrode of the nonaqueous electrolyte battery. This is an important part for isolating the positive electrode and the negative electrode to prevent a short circuit and ensuring ionic conductivity between the positive electrode and the negative electrode.

Therefore, it is further advantageous if the molded body as the carbon monoxide absorbent can function as a separator.

As a molded body that can be suitably used as a battery separator, a porous film containing a thermoplastic resin and a filler has been proposed (for example, Patent Document 3). This film is capable of adsorbing one or more gases of CO ₂ , CO, CH ₄ and C ₂ H ₄ that are generated by decomposition of the electrolytic solution and can deteriorate the battery performance. Carbon black and calcium carbonate are used. However, carbon black and calcium carbonate have insufficient CO absorption function. Further, since carbon black has conductivity, when it is filled in the separator, there is a risk of battery failure due to a short circuit.

A separator for a non-aqueous electrolyte secondary battery in which a gas absorbent is mixed in a separator base material such as a porous film made of a polyolefin resin is also known (for example, Patent Document 4). However, the gas to be absorbed is not specified, and the gas absorbent is not a combination of a carbon monoxide oxidation catalyst and a carbon dioxide adsorbing material.

JP 2004-188243 A International Publication No. 2005/120686 Pamphlet JP 2004-139933 A JP 2008-146963 A

The present inventor has obtained that a porous film can be obtained by stretching the molded body as the carbon monoxide absorbent, and that the obtained porous film absorbs carbon monoxide when disposed between the electrodes of the battery. It has been found that it can function not only as a material but also as a separator, so that it does not impair the demands for battery size reduction and capacity increase.

That is, the present invention
(A) 100 parts by mass of resin,
A porous film comprising a resin composition comprising (B) 1 to 300 parts by mass of a carbon monoxide oxidation catalyst and (C) 1 to 300 parts by mass of a carbon dioxide adsorbing substance.

The porous film of the present invention is porous and has a carbon monoxide absorption function, and can function as a carbon monoxide absorber and separator when disposed between electrodes of a non-aqueous electrolyte secondary battery. It is very advantageous in terms of maintaining the performance of the battery and reducing the size and capacity of the battery.

In the present specification, the “porous film” means a film having air permeability. The air permeability is indicated by the Gurley air permeability measured according to JIS P8117. The smaller the Gurley air permeability value, the greater the air permeability of the film. When the porous film of the present invention is used as a battery separator, the Gurley air permeability is preferably 1000 seconds / 100 cc or less. More preferably, it is 100 to 1000 seconds / 100 cc, and particularly 200 to 600 seconds / 100 cc.

The component (A) in the present invention may be anything as long as it is a resin, and includes, for example, a thermoplastic resin, a thermosetting resin, a thermoplastic elastomer, and rubber. Specifically, ethylene-based copolymer such as ultra-low density polyethylene, linear low-density polyethylene, low-density polyethylene, and high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate, etc. Examples thereof include a polymer, a propylene-based polymer, and a propylene-based copolymer. Examples of the rubber include ethylene-α olefin copolymer rubber, ethylene propylene rubber (EPDM), butyl rubber (IIR), isoprene rubber, and hydrogenated styrene elastomer. Examples of the α olefin include propylene, 1-butene, 1-hexene, 1-octene and 1-decane.

Component (A) is an ethylene containing an ethylene polymer (A-1) and an acid-modified ethylene resin (A-2) in terms of miscibility with components (B) and (C) as fillers. It is preferable that it is a resin composition. The ethylene polymer (A-1) is excellent in filler acceptability, and the acid-modified ethylene resin (A-2) improves the dispersion of the component (B) and the component (C) in the component (A).

Examples of the ethylene polymer (A-1) include low density polyethylene, linear low density polyethylene, ultra low density polyethylene, high density polyethylene, ethylene and α-olefin (for example, 1-butene, 1-hexene, 1 -Octene and the like), and these can be used alone or in combination of two or more.

In addition, when the battery separator has low heat resistance, it may occur that the battery separator melts at a temperature within a range assumed as a normal use environment of the battery to block ion movement between the electrodes. Therefore, it is particularly preferable that the ethylene polymer (A-1) satisfies the following (i) to (iv) so as to have sufficient miscibility with the filler and sufficient heat resistance.
(I) The peak top melting point (Tm) on the highest temperature side in the DSC melting curve is 110 ° C. or higher.
(Ii) The heat of fusion (ΔH) in the DSC melting curve is 90 to 180 J / g.
(Iii) The crystallinity (Xc110) at 110 ° C. is 10 to 60%, and (iv) MFR (190 ° C., 21.18N) is 0.1 g / 10 min or more and less than 10 g / 10 min.

When the peak top melting point (Tm) is lower than 110 ° C., the heat resistance may be insufficient. The peak top melting point (Tm) is preferably 120 ° C. or higher, more preferably 125 ° C. or higher.

Further, if the heat of fusion (ΔH) is less than 90 J / g, the heat resistance may be insufficient, and if it exceeds 180 J / g, the miscibility with the filler becomes insufficient and the film-forming property is poor. There is a case. The heat of fusion (ΔH) is preferably 100 to 170 J / g.

Further, if the crystallinity (Xc110) is less than 10%, the heat resistance may be insufficient, and if it exceeds 60%, the miscibility with the filler may be insufficient and the film forming property may be poor. The crystallinity (Xc110) is preferably 15 to 45%. The crystallinity at 110 ° C. means the ratio of the heat of fusion at 110 ° C. or higher to the total heat of fusion ΔH in the DSC melting curve.

Furthermore, when the MFR is 10 g / 10 min or more, the miscibility between the polyethylene resin composition (A) and the water-absorbing filler (B) is insufficient, or the pullability during film formation is reduced. If it is less than 0.1 g / 10 minutes, it may be difficult to adjust the thickness of the film. The MFR is preferably 0.2 to 7 g / 10 min, most preferably 0.5 to 5 g / 10 min.

In the present specification, unless otherwise specified, DSC melting curves are obtained by using a DSC Q1000 model of TA Instruments (TE Instruments Japan Co., Ltd.) and holding the sample at 190 ° C. for 5 minutes. Obtained by performing DSC measurement with a temperature program of cooling to −10 ° C. at a temperature decrease rate of 10 ° C./min, holding at −10 ° C. for 5 minutes, and then heating to 190 ° C. at a temperature increase rate of 10 ° C./min. It is a curved line.

When a mixture of ethylene polymers is used as the ethylene polymer (A-1), the entire mixture may satisfy the above requirements (i) to (iv).

Specific examples that can be used as the ethylene polymer (A-1) include ultra-low density polyethylene commercially available under the trade name KF360 from Nippon Polyethylene Co., Ltd. and linear chains commercially available under the trade names KF271 and UF240. Linear low density polyethylene commercially available from Prime Polymer Co., Ltd. under the trade names SP2040 and SP2520.

The acid-modified ethylene-based resin (A-2) is an ethylene-based resin obtained by graft polymerization and / or copolymerization of an unsaturated carboxylic acid or derivative thereof, and may be used alone or in combination of two or more. Can do. Examples of unsaturated carboxylic acids include, for example, maleic acid, itaconic acid, fumaric acid, and examples of derivatives thereof include, for example, maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid monoester, Examples include itaconic acid diester, itaconic anhydride, fumaric acid monoester, fumaric acid diester, fumaric anhydride and the like. Examples of the ethylene resin include linear polyethylene, ultra-low density polyethylene, high density polyethylene, ethylene-vinyl acetate (VA) copolymer, ethylene-ethyl acrylate (EA) copolymer, and ethylene-methacrylate copolymer. Is mentioned.

The acid-modified ethylene resin (A-2) preferably has an MFR (190 ° C., 21.18 N) of 0.1 to 10 g / 10 min. More preferably, it is 0.2 to 7 g / 10 minutes, and most preferably 0.5 to 5 g / 10 minutes. If the MFR is higher than the above upper limit, the drawability during film formation may be reduced. If the MFR is lower than the lower limit, it may be difficult to adjust the thickness of the film.

Specific examples of the acid-modified ethylene resin (A-2) include Admer (trade name) manufactured by Mitsui Chemicals, Adtex (trade name) manufactured by Nippon Polyolefin Co., Ltd., and Polybond manufactured by Crompton (product) Name) and Bond First (trade name) manufactured by Sumitomo Chemical Co., Ltd.

From the viewpoint of miscibility with the component (B) and the component (C), the polyethylene resin composition is composed of 99 to 60% by mass of the ethylene polymer (A-1) and the acid-modified ethylene resin (A-2). 1 to 40% by mass (here, the total amount of component (A-1) and component (A-2) is 100% by mass). More preferably, they are 97 to 70% by mass of the ethylene polymer (A-1) and 3 to 30% by mass of the acid-modified ethylene resin (A-2), and more preferably, the ethylene polymer (A-1). 95 to 80% by mass and 5 to 20% by mass of the acid-modified ethylene resin (A-2).

As the component (B), any of composite metal oxide catalysts such as hopcalite (copper-manganese composite oxide) and supported noble metal catalysts known as carbon monoxide oxidation catalysts can be used. The supported noble metal catalyst includes a metal oxide-supported noble metal catalyst such as palladium on alumina (a catalyst in which a noble metal is supported on the metal oxide surface), a noble metal-reducible oxide catalyst such as palladium-cerium oxide, titanium oxide-supported platinum, etc. A noble metal-supported photocatalyst, a supported Wacker type catalyst such as palladium chloride-copper chloride supported on carbon black, and a gold nanoparticle catalyst (a catalyst in which gold nanoparticles are supported on a metal oxide surface). Although it is more preferable if poisoning / deactivation with high concentration of carbon monoxide is difficult to occur, in the present invention, by incorporating component (B) into component (A), poisoning / deactivation of component (B) The effect of preventing / suppressing was also obtained. In the resin composition of the present invention, a composite metal oxide such as hopcalite and a metal oxide-supported noble metal catalyst such as palladium on alumina and palladium on magnesium oxide are preferably used. A carbon monoxide oxidation catalyst can be used individually by 1 type or in combination of 2 or more types. Even if the composition is the same as that of hopcalite, it is not in the form of a complex oxide, but in the form of a mixture in which copper (II) oxide and manganese (IV) oxide are simply mixed. Insufficient function.

As the component (C), strontium oxide, calcium oxide, zeolite having a pore diameter of 0.4 nm or more, and magnesium oxide having a BET specific surface area of 50 m ² / g or more can be preferably used. A component (C) can be used individually by 1 type or in combination of 2 or more types.

Component (B) and Component (C) have a particle size distribution of 30 μm or less (D99) and a particle size of 20 μm or less (D50) as the particle size distribution from the viewpoint of miscibility with component (A) and melt kneading. What has is preferable. Here, D99 and D55 refer to the particle diameter at the point where the particle diameter distribution becomes 99 mass% and 50 mass%, respectively, from the smaller particle diameter. D99 is preferably 20 μm or less, more preferably 15 μm or less. D50 is preferably 0.01 to 15 μm, more preferably 0.1 to 10 μm. Coarse particles that deviate from the above range may become a defect or foreign matter of the resulting film. In addition, if the particles are too fine, they will aggregate and become defects or foreign matter of the resulting film, or if they do not aggregate, a large amount of air will be embraced, resulting in poor melt-kneading workability during compound production. There is a case.

Control of the particle size distribution includes a method in which large particles are produced and then pulverized and sized, and a method in which fine particles are produced and sized from the beginning. Either method may be used as long as the particle size distribution can be controlled within the above range, and is not particularly limited. However, from the viewpoint of extrusion load and moldability, a method of generating fine particles from the beginning is more preferable.

The amount of component (B) is 1 to 300 parts by weight, preferably 3 to 200 parts by weight, more preferably 5 to 150 parts by weight, based on 100 parts by weight of component (A). If the amount is less than the lower limit, the function of oxidizing carbon monoxide to carbon dioxide becomes unsatisfactory. When the above upper limit is exceeded, melt kneading at the time of compound production and raw film forming may become difficult. In addition, it becomes difficult to apply a stretching method to impart porosity.

The amount of component (C) is 1 to 300 parts by weight, preferably 10 to 250 parts by weight, more preferably 20 to 200 parts by weight, based on 100 parts by weight of component (A). If the amount is less than the lower limit, the function of oxidizing carbon monoxide to carbon dioxide becomes unsatisfactory. When the above upper limit is exceeded, melt kneading at the time of compound production and raw film forming may become difficult. In addition, it becomes difficult to apply a stretching method to impart porosity.

The resin composition for the porous film of the present invention preferably further contains a slip agent. Thereby, the melt-kneading workability at the time of manufacturing the compound can be improved, and the moldability can be further improved. Examples of the slip agent include metal soaps such as calcium stearate, fatty acid amides such as oleic acid amide and erucic acid amide, polyethylene wax, silicone gum, and silicone oil. A preferable amount of the slip agent to be added is 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the component (A).

The resin composition for the porous film of the present invention may further contain a moisture absorbent. Thereby, the removal of moisture can be performed simultaneously with the removal of carbon monoxide. As the moisture absorbent, A-type zeolite such as molecular sieve 3A, molecular sieve 4A, molecular sieve 5A and the like is preferable. The amount of the water absorbent added is preferably 5 to 200 parts by weight, more preferably 10 to 150 parts by weight, and still more preferably 15 to 120 parts by weight with respect to 100 parts by weight of the component (A).

In addition, the resin composition for the porous film of the present invention includes, as necessary, a phosphorus-based, phenol-based, sulfur-based antioxidant, an anti-aging agent, a light stabilizer, a weathering agent such as an ultraviolet absorber, Anti-copper agent, aromatic phosphate metal salt-based, gelol-based nucleating agent, anti-static agent such as glycerin fatty acid monoester, coloring agent, fragrance, antibacterial agent, magnesium oxide, zinc oxide, calcium carbonate, talc In addition, additives such as fillers such as metal hydrates, plasticizers such as glycerin fatty acid ester-based, paraffin oil, phthalic acid-based and ester-based plasticizers may be included.

The resin composition for the porous film of the present invention can be obtained by melt-kneading necessary components. The melt-kneading can be performed using a conventional apparatus such as a twin screw extruder or a Banbury mixer. The kneading temperature is preferably higher than the molding temperature in order to avoid moisture absorption foaming troubles during molding. The obtained resin composition can be pelletized by a granulator and then subjected to normal film formation using a T die or the like. In that case, the pelletization is performed using water such as a hot cut method. It is preferable to carry out by a method that does not intervene. Further, a vacuum vent may be provided or a gear pump or the like may be used. Furthermore, it is also possible to use a method in which film formation is directly performed without pelletization, for example, a method in which a composition obtained by melt kneading is directly sent to a T die via a gear pump or the like to form a film.

The porous film of the present invention can be obtained by imparting porosity to the film obtained above. The method for imparting porosity is not particularly limited, and examples thereof include the following.
1. A chemical foaming agent is blended in advance with the resin composition to form a film, and then the foaming agent is decomposed at an appropriate temperature.
2. After the film is impregnated with carbon dioxide as a supercritical fluid, it is vaporized.
3. A plasticizer or the like is preliminarily blended into the resin composition to form a film, and then the plasticizer is extracted by an appropriate method.
4). The film is stretched at an appropriate temperature to generate microvoids at the crystal / amorphous interface or the resin / filler interface.
5. A hole is mechanically opened in the film with a cutting blade, a needle or the like.

Among these, the methods 4 and 5 are preferable in that no additional substances are required and therefore the oxidation catalyst and the adsorbed substance are not deteriorated. In addition, since the film in the present invention before imparting porosity has a uniform film thickness and good appearance (no defects such as blisters), it has a uniform film thickness and good appearance by stretching it. From the viewpoint of obtaining a porous film, the above method 4 is particularly preferred. The draw ratio is appropriately adjusted depending on the types and blending amounts of the components (B) and (C), but is usually about 1.1 to 8 times, preferably about 1.2 to 5 times in the vertical and horizontal directions. The stretching temperature is appropriately adjusted depending on the properties of the component (A) that is the base of the film, but a temperature lower than the normal stretching conditions is preferable for the purpose of imparting porosity. Specifically, the crystallinity of component (A) at the stretching temperature is selected to be 70% or less.

The obtained molded body can be subjected to γ-ray irradiation or vulcanization as necessary.

The porous film of the present invention thus obtained has a good appearance and no visible defects such as perforations, so there is no risk of short circuit, the thickness is uniform, and it has sufficient carbon monoxide processing capability. Therefore, it can be advantageously used as a separator in a nonaqueous electrolyte battery.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to a following example.

Examples 1 to 8, Comparative Examples 1 to 5 and Reference Example 1
The components (parts by mass) shown in Table 1 were dry blended and melt-kneaded with a twin screw extruder TEX28 of Nippon Steel, Ltd. to obtain a resin composition. A film (a) having a film thickness of 100 μm was obtained by forming a film using a T-die manufactured by the company. The manufacturing conditions are as follows.
Resin temperature at twin screw extruder outlet 220 ° C (use vacuum vent)
Gear pump outlet resin temperature 220 ℃
T-die outlet resin temperature 220 ° C
Chill roll temperature 40 ℃
Take-up speed: 6 m / min. Next, the film (a) obtained above was set to 2.0 × both vertically and horizontally at the stretching temperatures shown in Table 1 using a table-type test stretching device manufactured by Toyo Seiki Seisakusho Co., Ltd. The film was stretched twice to obtain a porous film (b) having a film thickness of 25 μm. The obtained porous film (b) was stored in a gas substitution type glove box (SG-1000 of ASONE CORPORATION) having a dew point temperature of −50 ° C. or lower. The following evaluation tests (1) to (6) were conducted. The results are shown in Table 1. For Examples 2 and 8, the following test (7) was also conducted.

(1) Film appearance Ten films (b) cut to a size of 10 cm × 10 cm were visually observed and judged according to the following criteria.
○: There is no perforation or puncture.
(Triangle | delta): There is no perforation, but there is a flaw.
X: There are both perforations and lumps.

(2) The Gurley air permeability of the air permeability film (b) was measured according to JIS P8117 using an Oken type air permeability tester manufactured by Asahi Seiko Co., Ltd.

(3) Concentration change of carbon monoxide and carbon dioxide in a nitrogen / carbon monoxide mixed gas A film (b) of 1000 cm ² was placed in a tetrabag, and 255 mL of nitrogen was filled therein. 45 mL of carbon monoxide was injected here (calculated concentration of carbon monoxide: 15 vol%). This was left for 24 hours at room temperature and normal pressure, and then the carbon monoxide concentration and the carbon dioxide concentration were measured by a gas chromatograph. In addition, since gas permeate | transmits and escapes little by little from a tetra bag, when the measurement of a blank (when the said film is not used) was also performed simultaneously, the carbon monoxide density | concentration after 24 hours is 14.1 vol%, Carbon was not detected.

(4) Concentration change of carbon monoxide and carbon dioxide in air / carbon monoxide mixed gas In the test of (3) above, 255 mL of air (nitrogen / oxygen = 80/20 (volume) instead of 255 mL of nitrogen The measurement was carried out in the same manner as in the test (3) except that the ratio)) was used. The carbon monoxide concentration in the blank was 14.2 vol%, and no carbon dioxide was detected.

(5) Change in concentration of carbon dioxide in nitrogen / carbon dioxide mixed gas Since carbon dioxide has high permeability, the carbon dioxide adsorption ability by the film was measured. In the above test (3), the carbon dioxide concentration was measured in the same manner as in the test (3) except that 45 mL of carbon dioxide was injected instead of 45 mL of carbon monoxide. The carbon dioxide concentration in the blank was 12.3 vol%.

(6) Heat resistance Using an HG-100 type heat seal tester manufactured by Toyo Seiki Seisakusho Co., Ltd., the two films (b) at a predetermined sealing temperature of 80 to 130 ° C., the longitudinal stretching direction of which is a T-shaped peel test. It fused so that it might become a tension direction (3 seconds, pressure 0.2MPa). Next, a T-peel test was performed using an AE-CT type tensile tester manufactured by Toyo Seiki Seisakusho Co., Ltd., with a peeling width of 25 mm, a peeling speed of 100 mm / min, and a peeling angle of 180 °. Films with good heat resistance are those that are judged to have a higher sealing temperature.
○: No or little fusion (peeling strength <0.1 N / 25 mm)
Δ: Slightly fused (peeling strength 0.1 to 2.0 N / 25 mm)
X: Fusing (peeling strength> 2.0 N / 25 mm)

(7) Water absorption ability Dimethyl carbonate (DMC) / diethyl carbonate (DEC) / ethylene carbonate (EC) = 1/1/1 (volume ratio) was mixed with a very small amount of water to prepare a test solution. The amount of water in this test solution was measured with a Karl Fischer volumetric titrator (AQ-300 from Hiranuma Sangyo Co., Ltd.) and found to be 982 ppm. Next, a film (b) of 450 cm ² was immersed in 30 g of this test solution, and the water content in the test solution was similarly measured after 25 ° C. × 48 hours. The above operation was carried out in a gas substitution type glove box (SG-1000 from ASONE CORPORATION) having a dew point temperature of −50 ° C. or lower by means of an air dryer QD20-75 manufactured by ICC Corporation.

The materials used are as follows.
Ingredient (A)
KF271: Nippon Polyethylene Corporation, linear low density polyethylene, Tm = 127 ° C., ΔH = 127 J / g, Xc110 = 26%, Xc110 = 26%, MFR (190 ° C., 21.18 N) = 2.4 g / 10 minutes, density 913 kg / m ³
Admer XE070: manufactured by Mitsui Chemicals, maleic anhydride-modified ethylene polymer, MFR (190 ° C., 21.18N) = 3 g / 10 minutes Admer XM7070: manufactured by Mitsui Chemicals, propylene-based random copolymer , MFR (230 ° C., 21.18 N) = 7 g / 10 min

Ingredient (B)
Hopcalite: Composite metal oxide catalyst (CuMn ₂ O ₄ ) manufactured by GL Sciences, pulverized and classified in a mortar, D99 = 12 μm, D50 = 3 μm
5% Pd—MgO-01: Magnesium oxide-supported palladium catalyst manufactured by N.E. Chemcat Co., Ltd., 5 mass%, D99 = 6 μm, D50 = 2 μm

Comparative component (B)
Carbon black: manufactured by Denki Kagaku Kogyo Co., Ltd., D99 = 2.1 μm (value as an aggregate), D50 = 0.5 μm (value as an aggregate)
Calcium carbonate: Softon 1800 manufactured by Bihoku Flour Industry Co., Ltd., D99 = 17 μm, D50 = 2.8 μm

Ingredient (C)
Starmag U: High BET magnesium oxide manufactured by Kamishima Chemical Industry Co., Ltd., BET specific surface area = 125 m ² / g, D99 = 6 μm, D50 = 2 μm
Zeolum A4 LPH: manufactured by Tosoh Corporation, type A zeolite with a pore size of 0.4 nm (molecular sieve 4A), D99 = 20 μm, D50 = 12 μm
STO: manufactured by Sakai Chemical Industry Co., Ltd., strontium oxide, coarse powder classified, D99 = 18 μm, D50 = 5 μm

Comparison of component (C) Starmag P: Magnesium oxide from Kamishima Chemical Co., Ltd., BET specific surface area = 10 m ² / g, D99 = 9 μm, D50 = 3 μm

Other materials: Slip agent LBT-77: Polyethylene wax calcium stearate molecular sieve 3A powder manufactured by Sakai Chemical Industry Co., Ltd .: Union Showa Co., Ltd., A-type zeolite having a pore size of 0.3 mm, coarse powder classified, D99 = 19 μm, D50 = 9 μm

As is apparent from Table 1, the porous films of the present invention of Examples 1 to 8 have a good appearance, excellent absorption and adsorption function of carbon monoxide and carbon dioxide, air permeability, and heat resistance. Is sufficient for battery separators. As a safety mechanism, non-aqueous electrolyte batteries stop the exchange of ions between electrodes when the battery is exposed to a high temperature of 100 to 130 ° C., the separator material melts and closes the holes. ). Therefore, when the porous film of the present invention is used as a separator, it needs heat resistance that does not melt up to 100 ° C.

Moreover, the said test (7) was also done about the film of Example 2 which uses the molecular sieve 4A as a component (C), and Example 8 containing a water | moisture-content absorber. As a result, with respect to the initial water content of 982 ppm, the water content after 48 hours of immersion was 17 ppm in Example 2 and 18 ppm in Example 8, and both showed sufficient water absorption ability.

On the other hand, the films of Comparative Examples 1 and 2 that do not contain the component (B) do not have a carbon monoxide absorbing function. Although the film of Comparative Example 3 containing no component (C) was able to oxidize carbon monoxide, it could not adsorb carbon dioxide. In Comparative Example 4 in which the blending amount of component (B) is too large and Comparative Example 5 in which the blending amount of component (C) is too large, the extrusion load increases during continuous production of melt-kneading and raw film formation, and the screw stops. However, a raw film could not be obtained. Therefore, tests (1) to (6) could not be performed.

In Reference Example 1, magnesium oxide having a low BET specific surface area was used as the component (C). Magnesium oxide with a low BET specific surface area requires water to absorb carbon dioxide. Therefore, in the tests (3) to (5) performed in an absolutely dry state, carbon monoxide could be oxidized, but carbon dioxide could not be adsorbed.

Claims

(A) 100 parts by mass of resin,
(B) A porous film comprising a resin composition comprising 1 to 300 parts by mass of a carbon monoxide oxidation catalyst and (C) 1 to 300 parts by mass of a carbon dioxide adsorbing substance.
The porous film according to claim 1, wherein component (B) comprises at least one selected from the group consisting of hopcalite and a supported noble metal catalyst.
The component (C) includes at least one selected from the group consisting of strontium oxide, calcium oxide, zeolite having a pore diameter of 0.4 nm or more, and magnesium oxide having a BET specific surface area of 50 m 2 / g or more. Or the porous film of 2.
The porous film according to any one of claims 1 to 3, wherein the component (A) is an ethylene resin composition containing an ethylene polymer and an acid-modified ethylene resin.
Component (A) is (A-1) 99 to 60% by mass of an ethylene polymer having the following characteristics (i) to (iv):
(I) The peak top melting point (Tm) on the highest temperature side in the DSC melting curve is 110 ° C. or higher.
(Ii) The heat of fusion (ΔH) in the DSC melting curve is 90 to 180 J / g.
(Iii) the crystallinity (Xc110) at 110 ° C. is 10 to 60%, and (iv) the MFR (190 ° C., 21.18N) is 0.1 g / 10 min or more and less than 10 g / 10 min, and
(A-2) Acid-modified resin 1 to 40% by mass
The porous resin composition according to any one of claims 1 to 4, wherein the total amount of component (A-1) and component (A-2) is 100% by mass. Quality film.
The porous film according to any one of claims 1 to 5, which has been given porosity by stretching at least 1.1 to 8 times in a uniaxial direction.
The porous film according to any one of claims 1 to 6, which has a Gurley air permeability of 100 to 1000 seconds / 100 cc.
A non-aqueous electrolyte secondary battery comprising the porous film according to any one of claims 1 to 7 in a container in which a power storage element is enclosed.
An electric double layer capacitor comprising the porous film according to any one of claims 1 to 7 in a container in which a power storage element is enclosed.