Polypropylene resin composition for battery packaging material, method for producing same, film, and battery packaging material

Abstract

A polypropylene-based resin composition for a battery packaging material, which contains: a polypropylene-based resin (A) that contains a continuous phase comprising a propylene polymer (a1) and a rubber phase comprising a copolymer (a2) of ethylene (Et) and an alpha-olefin having 3-10 carbon atoms; the present invention relates to an ethylene-alpha-olefin copolymer composition comprising (A) an ethylene-alpha-olefin copolymer and (B) an arbitrary component, in which the content ratio of A is 90-100% by mass of the composition, the content ratio of B is 0-10% by mass of the total mass of A and B, the MFR of the composition is 0.5-12.0 g / 10 minutes, the Mw / Mn of a1 is less than 8, the Et derived unit content in a1 is 7.0% by mass or less, the content of a2 is 30-43% by mass of A, and the content ratio of A to B is 0-10% by mass of the total mass of A and B. The content of Et derived units in a2 is 20 to 40 mass%, the XSIV of A is 2.5 to 3.5 dl / g, and the MFR of A is 0.5 to 12.0 g / 10 minutes.

Description

Technical Field

[0001] The present invention relates to a polypropylene resin composition for battery packaging materials, a method for manufacturing the same, a film, and a battery packaging material. Background Art

[0002] Polypropylene is excellent in physical properties such as impact resistance, rigidity, transparency, chemical resistance, and heat resistance, and is thus used in various applications. For example, Patent Document 1 discloses a polypropylene resin composition that is excellent in the balance between rigidity and impact resistance and is suitable for obtaining an injection molded product with good appearance.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 2019-189818 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] As uses of a film of a polypropylene resin composition, for example, a bag for steaming food, a packaging material for an electrode laminate of a lithium-ion secondary battery, etc. can be cited. Especially in the use as a packaging material for an electrode laminate of a lithium-ion secondary battery, in the manufacturing process of the lithium-ion secondary battery, the packaging material comes into contact with the electrolyte, and thus it is required that the packaging material maintain its performance after the contact. Specifically, it is required that the packaging material has high heat sealability (weldability) to ensure that the electrolyte does not leak. Also, the packaging material is processed into a shape that can hold the electrode laminate, and it is required that whitening or the like does not occur during this processing.

[0008] The polypropylene resin composition disclosed in Patent Document 1 is not suitable for film forming due to its high MFR. In addition, this composition neither considers satisfying various mechanical and chemical properties required for a film nor considers the electrolyte resistance required for a packaging material for an electrode laminate of a lithium-ion secondary battery.

[0009] The present invention provides a polypropylene resin composition for battery packaging materials, a method for manufacturing the same, a film, and a battery packaging material, which are excellent in productivity and suitable for battery packaging materials.

[0010] The present invention has the following aspects.

[0011] Aspect 1

[0012] A polypropylene resin composition for battery packaging materials, comprising:

[0013] A polypropylene resin (A) comprising a continuous phase composed of a propylene polymer (a1) and a rubber phase composed of a copolymer (a2) of ethylene and an α-olefin having 3 to 10 carbon atoms; and

[0014] An ethylene-α-olefin copolymer (B) as an optional component, which is a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms,

[0015] wherein,

[0016] The content ratio of the polypropylene resin (A) is 90 to 100% by mass of the total mass of the polypropylene resin composition,

[0017] The content ratio of the ethylene-α-olefin copolymer (B) is 0 to 10% by mass of the total mass of (A) and (B),

[0018] The MFR of the polypropylene resin composition at a temperature of 230 °C and a load of 2.16 kg is 0.5 to 12.0 g / 10 minutes,

[0019] The ratio (Mw / Mn) of the weight-average molecular weight Mw to the number-average molecular weight Mn of the propylene polymer (a1) is less than 8,

[0020] The content of ethylene-derived units in the propylene polymer (a1) is 7.0% by mass or less of the total mass of the propylene polymer (a1),

[0021] The content of the copolymer (a2) is 30 to 43% by mass of the total mass of the polypropylene resin (A),

[0022] The content of ethylene-derived units in the copolymer (a2) is 20 to 40% by mass of the total mass of the copolymer (a2),

[0023] The intrinsic viscosity of the xylene-soluble component of the polypropylene resin (A) in tetralin at 135 °C is 2.5 to 3.5 dl / g,

[0024] The MFR of the polypropylene resin (A) at a temperature of 230 °C and a load of 2.16 kg is 0.5 to 12.0 g / 10 minutes.

[0025] Method 2

[0026] The polypropylene resin composition according to Method 1, wherein the propylene polymer (a1) and the copolymer (a2) are mixed by polymerization, and the polypropylene resin (A) is a polymerization mixture produced using a catalyst containing the following components (x) to (z).

[0027] (x) A solid catalyst containing magnesium, titanium, halogen, and a phthalate compound as an electron donor compound

[0028] (y) An organoaluminum compound

[0029] (z) An organosilicon compound as an external electron donor compound

[0030] Method 3

[0031] The polypropylene resin composition according to Method 1 or Method 2, wherein the battery is a lithium-ion battery.

[0032] Method 4

[0033] A film formed by molding the polypropylene resin composition according to any one of Methods 1 to 3.

[0034] Method 5

[0035] A battery packaging material comprising the film according to Method 4.

[0036] Method 6

[0037] A method for producing a polypropylene resin composition, which is a method for producing the polypropylene resin composition according to any one of Methods 1 to 3, wherein the production method has the following steps: using a catalyst containing the following components (x) to (z), and polymerizing a raw material monomer in the presence of the propylene polymer (a1) to obtain the polypropylene resin (A).

[0038] (x) A solid catalyst containing magnesium, titanium, halogen, and a phthalate compound as an electron donor compound

[0039] (y) An organoaluminum compound

[0040] (z) An organosilicon compound as an external electron donor compound

[0041] Advantages of the Invention

[0042] It is possible to provide a polypropylene resin composition, a method for producing the same, a film, and a battery packaging material, which have excellent productivity and are suitable for battery packaging materials. Description of the Drawings

[0043] Figure 1 It is a diagram showing a method of packaging a battery electrode laminate.

[0044] Figure 2 It is a diagram showing a method of a packaging material. Detailed Description

[0045] 1. Polypropylene resin composition

[0046] In one embodiment, the polypropylene resin composition contains a polypropylene resin (A) (hereinafter also referred to as "component (A)"). Component (A) includes a continuous phase composed of a propylene polymer (hereinafter also referred to as "component (a1)") and a rubber phase composed of a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms (hereinafter also referred to as "component (a2)"). Further, the polypropylene resin composition may contain an ethylene-α-olefin copolymer (B) (hereinafter also referred to as "component (B)") as an optional component, which is a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms, or may not contain the ethylene-α-olefin copolymer (B).

[0047] The content ratio of the polypropylene resin (A) is 90 to 100% by mass of the total mass of the polypropylene resin composition, and its lower limit value is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 99% by mass or more. As long as it is above the lower limit value of the said range, the above effects can be sufficiently obtained. If it does not reach the upper limit value of the said range, there is room for containing component (B) and other components.

[0048] The content ratio of the ethylene-α-olefin copolymer (B) is 0 to 10% by mass of the total mass of component (A) and component (B), and its upper limit value is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 0% by mass. When it exceeds the lower limit value of the said range, i.e., 0% by mass, the impact resistance of the film is improved. However, from the viewpoint of maintaining rigidity, the content ratio of component (B) is preferably 0% by mass. When it exceeds the upper limit value of the said range, i.e., 10% by mass, the breaking strength of the material itself decreases, resulting in a decrease in the heat seal strength of the film.

[0049] The MFR of the polypropylene resin composition at a temperature of 230°C and a load of 2.16 kg is 0.5 to 12.0 g / 10 minutes, and its lower limit value is preferably 1.0 g / 10 minutes or more, more preferably 1.5 g / 10 minutes or more. Further, the upper limit value is preferably 10.0 g / 10 minutes or less, more preferably 8.0 g / 10 minutes or less, and further preferably 6.0 g / 10 minutes or less. In other words, preferred ranges can be exemplified as 1.0 to 10.0 g / 10 minutes, 1.5 to 8.0 g / 10 minutes, or 1.5 to 6.0 g / 10 minutes, etc. Here, the MFR is a value measured according to the measurement method described below. When it is above the lower limit value of the said range, the film formability is excellent. When it is below the upper limit value of the said range, the mechanical properties of the film can be improved.

[0050] [Polypropylene resin (A)]

[0051] Polypropylene resin (A) is a type of impact-resistant polypropylene polymer specified in JIS K6921-1, and is composed of two or more phases including a continuous phase containing a propylene polymer (component (a1)) and a rubber phase of an ethylene-α-olefin copolymer (component (a2)) present as a dispersed phase in the continuous phase. The polypropylene resin (A) can be a mixed resin in which component (a1) and component (a2) are mixed during polymerization, or a mixed resin in which component (a1) and component (a2) separately prepared are mixed by melt-kneading.

[0052] From the perspective of excellent balance of rigidity, low-temperature impact resistance and tensile properties (hereinafter also referred to as "mechanical property balance"), a polymerization mixture in which component (a1) and component (a2) are mixed during polymerization is preferred. In the polymerization mixture, component (a1) and component (a2) can be mixed at the sub-micron level, and thus the polypropylene resin composition based on this polymerization mixture exhibits excellent mechanical property balance.

[0053] On the other hand, in the case of achieving the same uniform mixing and obtaining excellent mechanical property balance by using a simple mechanical mixture obtained by melt-kneading component (a1) and component (a2) separately prepared, since additional processes such as storage, storage, transportation, metering, mixing and melt-kneading are required, the manufacturing cost will increase. This is not a preferred solution from the perspective of energy cost.

[0054] The above-mentioned polymerization mixture and mechanical mixture sometimes exhibit different physical properties. It is speculated that the reason is the difference in the dispersion state of component (a2) in component (a1), but there is currently no practical means to analyze the molecular-level dispersion state including the interfacial state between component (a2) and component (a1). The manufacturing method of polypropylene resin (A) will be described in detail later.

[0055] The limiting viscosity of the xylene-soluble component of polypropylene resin (A) (hereinafter also referred to as "XSIV") is 2.5 to 3.5 dl / g. The lower limit value is preferably 2.7 dl / g or more. And the upper limit value is preferably 3.3 dl / g or less. In other words, preferred ranges can be exemplified such as 2.5 to 3.3 dl / g, 2.7 to 3.5 dl / g or 2.7 to 3.3 dl / g, etc. Here, XSIV is a value measured by the method described below. When it is above the lower limit value of the above range, the sealing strength of the film molded body is improved. When it is below the upper limit value of the above range, FE generated by the film can be reduced, and appearance defects (convex and concave small dots exposed) can be suppressed.

[0056] Specifically, XSIV is measured by obtaining the xylene-soluble component of the copolymer by the following method.

[0057] Place 2.5 g of the copolymer sample in a flask containing 250 mL of o-xylene (solvent). Using a heating plate and a reflux device, purge with nitrogen at 135 °C and stir for 30 minutes to completely dissolve it. Then, cool the sample at 25 °C for 1 hour. Filter the resulting solution using filter paper. Measure 100 mL of the filtered filtrate, transfer it to an aluminum cup, etc., purge with nitrogen, and evaporate to dryness at 140 °C. Let it stand at room temperature for 30 minutes to obtain the xylene-soluble component. Measure the intrinsic viscosity in tetralin at 135 °C using a capillary viscometer (e.g., SS-780-H1, manufactured by Shibayama Scientific Instruments Co., Ltd.).

[0058] The ratio (Mw / Mn) of the weight-average molecular weight Mw to the number-average molecular weight Mn, which is an index of the molecular weight distribution of the propylene polymer (component (a1)) constituting the polypropylene resin (A), is less than 8. When Mw / Mn is less than 8, the low-temperature impact resistance and whitening resistance of the film are improved. The Mw / Mn of component (a1) is preferably 7 or less. The lower limit value of the above ratio is not particularly limited, and examples of the reference value can be 3 or more. Here, the weight-average molecular weight Mw and the number-average molecular weight Mn of the propylene polymer are values measured by the method described below.

[0059] The content of the ethylene-derived unit in the propylene polymer (component (a1)) (hereinafter also referred to as "C2") is 7.0% by mass or less of the total mass of the propylene polymer. When C2 is below the above upper limit value, the rigidity of the film is improved. From this perspective, C2 is preferably 5.9% by mass or less, more preferably 4.3% by mass or less. The lower limit of C2 is not particularly limited and can be 0% by mass. In other words, component (a1) can be a polypropylene homopolymer composed only of propylene-derived units, or a copolymer composed of 99.5% by mass or more and less than 100% by mass of propylene-derived units and more than 0% by mass and 0.5% by mass or less of ethylene-derived units. On the other hand, for the purpose of preventing an explosion caused by gas generated from the battery, it is required that the packaging material exhibits a certain degree of gas leakage characteristics when the air pressure rises. By controlling C2 of component (a1) between 0.3 and 7.0% by mass, the breaking strength of the material itself (which in turn affects the heat-sealing strength of the film) can be adjusted, thereby optimizing the gas leakage characteristics. C2 is measured using 13 the C-NMR method.

[0060] The ethylene-α-olefin copolymer (Component (a2)) is a copolymer having ethylene-derived units and α-olefin-derived units with 3 to 10 carbon atoms. The content of the ethylene-derived units in Component (a2) is 20 to 40% by mass based on the total mass of Component (a2). The lower limit value is preferably 25% by mass or more, more preferably 28% by mass or more. And, the upper limit value is preferably 35% by mass or less, more preferably 33% by mass or less. In other words, the preferred ranges can be exemplified by ranges such as 20 to 35% by mass, 20 to 33% by mass, 25 to 40% by mass, 25 to 35% by mass, 25 to 33% by mass, 28 to 40% by mass, 28 to 35% by mass, or 28 to 33% by mass. When the content is above the lower limit value of the range, the electrolyte resistance is improved, and the low-temperature impact resistance of the film molded body is improved. When the content is below the upper limit value of the range, the whitening resistance can be improved. The content of the ethylene-derived units in Component (a2) is measured using 13 the C-NMR method.

[0061] Based on the total mass of the polypropylene resin (A), the content of the ethylene-α-olefin copolymer (Component (a2)) is 30 to 43% by mass. The lower limit value is preferably 31% by mass or more. And, the upper limit value is preferably 38% by mass or less, more preferably 35% by mass or less. In other words, the preferred ranges can be exemplified by ranges such as 30 to 38% by mass, 30 to 35% by mass, 31 to 43% by mass, 31 to 38% by mass, or 31 to 35% by mass. When the content is above the lower limit value of the range, the low-temperature impact resistance and electrolyte resistance of the film molded body are improved. When the content is below the upper limit value of the range, the risk of clogging of the flow path in the production equipment due to deterioration of the powder fluidity during the production of the polypropylene resin (A) can be reduced, and thus the polypropylene resin (A) can be stably and continuously produced.

[0062] Examples of the α-olefin constituting the ethylene-α-olefin copolymer (Component (a2)) include propylene (1-propene), 1-butene, 1-pentene, 1-hexene, 1-octene, etc. As specific Component (a2), examples include ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, etc. Among them, from the viewpoint of improving the productivity of the polypropylene resin (A), an ethylene-propylene copolymer is preferred.

[0063] The melt flow rate (MFR) of the polypropylene resin (A) at a temperature of 230 °C and a load of 2.16 kg is 0.5 to 12.0 g / 10 min. The lower limit value is preferably 1.0 g / 10 min or more, more preferably 1.5 g / 10 min or more. In addition, the upper limit value is preferably 10.0 g / 10 min or less, more preferably 8.0 g / 10 min or less, and even more preferably 6.0 g / 10 min or less. In other words, preferred ranges can be exemplified as 1.0 to 10.0 g / 10 min, 1.5 to 8.0 g / 10 min, or 1.5 to 6.0 g / 10 min, etc. Here, the MFR is a value measured by the method described below. When it is above the lower limit value of the said range, the film formability is excellent. When it is below the upper limit value of the said range, the sealing strength of the film can be improved, and the low-temperature impact resistance can be improved.

[0064] [Ethylene-α-olefin copolymer (B)]

[0065] The ethylene-α-olefin copolymer (B) is a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms. Examples of the α-olefin include propylene (1-propene), 1-butene, 1-pentene, 1-hexene, 1-octene, etc. Specific examples of the ethylene-α-olefin copolymer (B) include ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, etc. Among them, considering the availability of raw materials and economy, etc., ethylene-butene copolymer or ethylene-octene copolymer is preferred.

[0066] The melt flow rate (MFR) of the ethylene-α-olefin copolymer (B) at a temperature of 190 °C and a load of 2.16 kg is preferably 0.5 to 20 g / 10 min. Here, the MFR is a value measured by the measurement method described below. When the MFR is above the lower limit value of the said range, the fluidity of the polypropylene resin composition is improved. When the MFR is below the upper limit value of the said range, the generation of adhesion in the polypropylene resin composition can be suppressed, thereby improving the continuous productivity of the composition. Also, the low-temperature impact resistance and tensile properties of the film molded body are improved.

[0067] [Other components]

[0068] The polypropylene resin composition may contain, within the range not impairing the effects, polymers or additives other than the polypropylene resin (A) and the ethylene-α-olefin copolymer (B) as optional components. There are no restrictions on the polymers other than component (A) and component (B), and examples thereof include polypropylene resins different from component (A) (such as homopolypropylene, random propylene copolymers, multiphase propylene copolymers), polyethylene resins (such as HDPE, LDPE, LLDPE), known elastomers, plastomers, terpolymers, recycled polymers, etc. These polymers may be used alone or in combination of two or more. The content of the other polymer in the polypropylene resin composition is preferably 0 to 10% by mass.

[0069] Examples of the additives include antioxidants, neutralizing agents, nucleating agents, weathering agents, pigments (organic or inorganic), internal lubricants and external lubricants, anti-blocking agents, antistatic agents, chlorine absorbers, heat stabilizers, light stabilizers, ultraviolet absorbers, slip agents, antifogging agents, flame retardants, dispersants, copper inhibitors, plasticizers, foaming agents, defoaming agents, crosslinking agents, peroxides, oil filling, etc. These additives may be used alone or in combination of two or more. In addition, the content may be a known amount.

[0070] 2. Method for manufacturing polypropylene resin composition

[0071] As a method for manufacturing the polypropylene resin composition, a method of mixing the polypropylene resin (A) and the ethylene-α-olefin copolymer (B) as an optional component and then melt-kneading them can be cited.

[0072] As a mixing method, a dry mixing method using a mixer such as a Henschel mixer, a drum mixer, or a ribbon mixer can be cited.

[0073] As a melt-kneading method, a method of melting and mixing while using a mixer such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader, or a roll mill can be cited. The melting temperature during melt-kneading is preferably 160 to 350 °C, more preferably 170 to 260 °C. Granulation may be further performed after melt-kneading.

[0074] [Method for manufacturing polypropylene resin (A)]

[0075] The polypropylene resin (A) can be prepared by mixing a propylene polymer (component (a1)) and an ethylene-α-olefin copolymer (component (a2)) during polymerization. In addition, the polypropylene resin (A) can also be prepared by melt-kneading the separately produced component (a1) and component (a2). The polypropylene resin (A) is preferably a polymerization mixture prepared by mixing component (a1) and component (a2) during polymerization. Such a polymerization mixture is obtained by polymerizing raw material monomers, i.e., an ethylene monomer and an α-olefin monomer, in the presence of component (a1). According to this method, not only is the productivity improved, but also the dispersibility of component (a2) in component (a1) is improved, so that the mechanical property balance of the film molded body obtained by using it is enhanced.

[0076] Hereinafter, the case where an acrylonitrile monomer is used as the α-olefin monomer will be described. The same manufacturing method can be applied when other α-olefin monomers are used.

[0077] As a method for producing the polymerization mixture, a multi-stage polymerization method is typically employed. For example, in a polymerization apparatus equipped with a two-stage polymerization reactor, a propylene polymer is obtained by polymerizing a propylene monomer and, if necessary, an ethylene monomer using the first-stage polymerization reactor. Then, the obtained propylene polymer is supplied to the second-stage polymerization reactor, and at the same time, an ethylene monomer and a propylene monomer are polymerized using the second-stage polymerization reactor to produce the polymerization mixture.

[0078] The polymerization conditions can be the same as the known polymerization conditions. For example, as the first-stage polymerization conditions, a slurry polymerization method in which propylene is in a liquid phase and the monomer density is high and the productivity is high can be cited. As the second-stage polymerization conditions, a gas-phase polymerization method that generally has a high solubility for propylene and is easy to produce a copolymer can be cited. The polymerization temperature is preferably 50 to 90°C, more preferably 60 to 90°C, and further preferably 70 to 90°C. When the polymerization temperature is above the lower limit value of the above range, the productivity and the stereoregularity of the obtained polypropylene are more excellent.

[0079] Regarding the polymerization pressure, when carried out in a liquid phase, it is preferably 25 to 60 bar (2.5 to 6.0 MPa), more preferably 33 to 45 bar (3.3 to 4.5 MPa). When carried out in a gas phase, it is preferably 5 to 30 bar (0.5 to 3.0 MPa), more preferably 8 to 30 bar (0.8 to 3.0 MPa). Polymerization (polymerization of a propylene monomer, polymerization of an ethylene monomer and a propylene monomer, etc.) is usually carried out using a catalyst. Hydrogen can be added as needed during polymerization to adjust the molecular weight. By adjusting the molecular weight of the propylene polymer or the ethylene-propylene copolymer, the MFR of the polypropylene resin (A) can be adjusted, and further the MFR of the polypropylene resin composition can be adjusted.

[0080] Before polymerization in the first-stage polymerization reactor, prepolymerization of propylene can be carried out to form polymer chains on the solid catalyst component as the start of subsequent formal polymerization. The prepolymerization is usually carried out at a temperature below 40°C, preferably below 30°C, more preferably below 20°C.

[0081] As the catalyst, known olefin polymerization catalysts can be used. As the catalyst for polymerizing ethylene monomer and propylene monomer in the presence of the propylene polymer, a stereospecific Ziegler-Natta catalyst is preferred, and a catalyst containing the following components (x), (y) and (z) (hereinafter also referred to as "catalyst (X)") is particularly preferred.

[0082] (x) A solid catalyst containing magnesium, titanium, halogen and a phthalate compound as an electron donor compound as essential components.

[0083] (y) An organoaluminum compound.

[0084] (z) An organosilicon compound as an external electron donor compound.

[0085] The polypropylene resin (A) is preferably produced by a method having the following steps: using the catalyst (X), in the presence of the propylene polymer, polymerizing a raw material monomer (such as an ethylene monomer) and an α-olefin monomer (such as a propylene monomer) to obtain the polypropylene resin. By using the catalyst (X), a polypropylene resin (A) having physical properties within the above ranges can be easily obtained.

[0086] The molecular weight and stereoregularity distributions of the propylene polymer obtained by the catalyst used (especially the electron donor compound of component (x)) are different, and this difference affects the crystallization behavior, etc., but the details of the correlation are not yet clear. If you want to clarify the details, it is necessary to synchronously analyze the molecular weight distribution and stereoregularity distribution as the molecular structure. However, since components with different molecular weights and stereoregularities affect each other during the crystallization process, it is complex, making it more difficult to analyze the influence of the molecular weight and stereoregularity distributions on the crystallization behavior. In addition, the actual film forming is carried out in a molten resin flow state, so it is difficult to grasp this phenomenon even by using advanced analysis techniques. Therefore, for the polypropylene resin composition prepared using a specific catalyst, it is almost impossible to determine the difference in crystallization behavior caused by the distribution of specific molecular weights and stereoregularities by numerical values, etc. The molecular weight distribution and stereoregularity distribution are affected not only by the above catalyst type but also by thermal degradation during melt mixing, peroxide treatment, etc.

[0087] Component (x) can be prepared using, for example, a titanium compound, a magnesium compound and an electron donor compound. As the titanium compound used for component (x), a compound of the general formula Ti(OR)g Hal 4-g A tetravalent titanium compound represented by (wherein R is a hydrocarbon group, Hal is a halogen, and 0 ≤ g ≤ 4). Examples of the hydrocarbon group include methyl, ethyl, propyl, butyl, etc., and examples of the halogen include Cl, Br, etc.

[0088] More specific examples of the titanium compound include titanium tetrahalides such as TiCl4, TiBr4, and TiI4, alkoxytitanium trihalides such as Ti(OCH3)Cl3, Ti(OC2H5)Cl3, Ti(O n -C4H9)Cl3, Ti(OC2H5)Br3, Ti(O-isoC4H9)Br3), dialkoxytitanium dihalides such as Ti(OCH3)2Cl2, Ti(OC2H5)2Cl2, Ti(O n -C4H9)2Cl2, Ti(OC2H5)2Br2, monoalkoxytitanium trihalides such as Ti(OCH3)3Cl, Ti(OC2H5)3Cl, Ti(O n -C4H9)3Cl, Ti(OC2H5)3Br, and tetraalkoxytitaniums such as Ti(OCH3)4, Ti(OC2H5)4, Ti(O n -C4H9)4. These titanium compounds can be used alone or in combination of two or more.

[0089] Among the above titanium compounds, halogen-containing titanium compounds are preferred, titanium tetrahalides are more preferred, and titanium tetrachloride (TiCl4) is particularly preferred.

[0090] Examples of the magnesium compound used as component (x) include magnesium compounds having a magnesium-carbon bond or a magnesium-hydrogen bond, such as dimethylmagnesium, diethylmagnesium, dipropylmagnesium, dibutylmagnesium, dipentylmagnesium, dihexylmagnesium, didecylmagnesium, ethylmagnesium chloride, propylmagnesium chloride, butylmagnesium chloride, hexylmagnesium chloride, pentylmagnesium chloride, butylethoxymagnesium, ethylbutylmagnesium, butylmagnesium hydride, etc. These magnesium compounds can also be used, for example, in the form of a complex compound with organoaluminum, etc. In addition, they can be in a liquid state or a solid state. More preferred examples of the magnesium compound include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, and magnesium fluoride; alkoxymagnesium halides such as methoxymagnesium chloride, ethoxymagnesium chloride, isopropoxymagnesium chloride, butoxymagnesium chloride, and octoxymagnesium chloride; aryloxymagnesium halides such as phenoxymagnesium chloride and methylphenoxymagnesium chloride; alkoxymagnesiums such as ethoxymagnesium, isopropoxymagnesium, butoxymagnesium, n-octoxymagnesium, and 2-ethylhexoxymagnesium; dialkoxymagnesiums such as dimethoxymagnesium, diethoxymagnesium, dipropoxymagnesium, dibutoxymagnesium, and ethoxymethoxymagnesium; aryloxymagnesiums such as ethoxypropoxymagnesium, butoxyethoxymagnesium, phenoxymagnesium, and dimethylphenoxymagnesium. These magnesium compounds can be used alone or in combination of two or more.

[0091] The electron donor compound used for component (x) preferably contains a phthalate compound as an essential component. By using a catalyst (X) containing a phthalate compound as an electron donor, it is possible to easily obtain a polypropylene resin in which the Mw / Mn of the propylene polymer is within the above range. Examples of the phthalate compound include monoethyl phthalate, dimethyl phthalate, methyl ethyl phthalate, monoisobutyl phthalate, monon-butyl phthalate, diethyl phthalate, ethyl isobutyl phthalate, ethyl n-butyl phthalate, di-n-propyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-n-heptyl phthalate, bis(2-ethylhexyl) phthalate, di-n-octyl phthalate, di-neopentyl phthalate, didecyl phthalate, benzyl butyl phthalate, diphenyl phthalate, etc. Among them, diisobutyl phthalate (DIBP) is particularly preferred.

[0092] Examples of the electron donor compound in the solid catalyst other than the phthalate compound include succinate compounds and diether compounds.

[0093] The succinate compound may be an ester of succinic acid or an ester of a substituted succinic acid in which the 1-position or 2-position of succinic acid has a substituent such as an alkyl group. Specific examples include diethyl succinate, dibutyl succinate, diethyl methylsuccinate, diethyl diisopropylsuccinate, diallyl ethylsuccinate, etc.

[0094] As the diether compounds, for example, 2-(2-ethylhexyl)-1,3-dimethoxypropane, 2-isopropyl-1,3-dimethoxypropane, 2-butyl-1,3-dimethoxypropane, 2-sec-butyl-1,3-dimethoxypropane, 2-cyclohexyl-1,3-dimethoxypropane, 2-phenyl-1,3-dimethoxypropane, 2-tert-butyl-1,3-dimethoxypropane, 2-cumyl-1,3-dimethoxypropane, 2-(2-phenylethyl)-1,3-dimethoxypropane, 2-(2-cyclohexylethyl)-1,3-dimethoxypropane, 2-(p-chlorophenyl)-1,3-dimethoxypropane, 2-(diphenylmethyl)-1,3-dimethoxypropane, 2-(1-naphthyl)-1,3-dimethoxypropane, 2-(p-fluorophenyl)-1,3-dimethoxypropane, 2-(1-decahydronaphthyl)-1,3-dimethoxypropane, 2-(p-tert-butylphenyl)-1,3-dimethoxypropane, 2,2-dicyclohexyl-1,3-dimethoxypropane, 2,2-diethyl-1,3-dimethoxypropane, 2,2-dipropyl-1,3-dimethoxypropane, 2,2-dibutyl-1,3-dimethoxypropane, 2,2-diethyl-1,3-diethoxypropane, 2,2-dicyclopentyl-1,3-dimethoxypropane, 2,2-dipropyl-1,3-diethoxypropane, 2,2-dibutyl-1,3-diethoxypropane, 2-methyl-2-ethyl-1,3-dimethoxypropane, 2-methyl-2-propyl-1,3-dimethoxypropane, 2-propyl-2-pentyl-1,3-diethoxypropane, 2-methyl-2-benzyl-1,3-dimethoxypropane, 2-methyl-2-phenyl-1,3-dimethoxypropane, 2-methyl-2-cyclohexyl-1,3-dimethoxypropane, 2-methyl-2-methylcyclohexyl-1,3-dimethoxypropane, 2,2-bis(p-chlorophenyl)-1,3-dimethoxypropane, 2,2-bis(2-phenylethyl)-1,3-dimethoxypropane, 2,2-bis(2-cyclohexylethyl)-1,3-dimethoxypropane, 2-methyl-2-isobutyl-1,3-dimethoxypropane, 2-methyl-2-(2-ethylhexyl)-1,3-dimethoxypropane, 2,2-bis(2-ethylhexyl)-1,3-dimethoxypropane, 2,2-bis(p-methylphenyl)-1,3-dimethoxypropane, 2-methyl-2-isopropyl-1,3-dimethoxypropane, 2,2-diisobutyl-1,3-dimethoxypropane, 2,2-diphenyl-1,3-dimethoxypropane, 2,2-dibenzyl-1,3-dimethoxypropane, 2-isopropyl-2-cyclopentyl-1,3-dimethoxypropane, 2,2-bis(cyclohexylmethyl)-1,3-dimethoxypropane, 2,2-diisobutyl-1,3-diethoxypropane, 2,2-diisobutyl-1,3-dibutoxypropane, 2-isobutyl-2-isopropyl-1,3-dimethoxypropane, 2,2-di-sec-butyl-1,1,3-diether such as 3-dimethoxypropane, 2,2-di-tert-butyl-1,3-dimethoxypropane, 2,2-dineopentyl-1,3-dimethoxypropane, 2-isopropyl-2-isopentyl-dimethoxypropane, 2-phenyl-2-benzyl-1,3-dimethoxypropane, 2-cyclohexyl-2-cyclohexylmethyl-1,3-dimethoxypropane, etc.

[0095] In addition, as more specific examples of 1,3-diether compounds, the following examples can be cited.

[0096] 1,1-Bis(methoxymethyl)-cyclopentadiene; 1,1-bis(methoxymethyl)-2,3,4,5-tetramethylcyclopentadiene; 1,1-bis(methoxymethyl)-2,3,4,5-tetraphenylcyclopentadiene; 1,1-bis(methoxymethyl)-2,3,4,5-tetrafluorocyclopentadiene; 1,1-bis(methoxymethyl)-3,4-dicyclopentylcyclopentadiene; 1,1-bis(methoxymethyl)indene; 1,1-bis(methoxymethyl)-2,3-dimethylindene; 1,1-bis(methoxymethyl)-4,5,6,7-tetrahydroindene; 1,1-bis(methoxymethyl)-2,3,6,7-tetrafluoroindene; 1,1-bis(methoxymethyl)-4,7-dimethylindene; 1,1-bis(methoxymethyl)-3,6-dimethylindene; 1,1-bis(methoxymethyl)-4-phenylindene; 1,1-bis(methoxymethyl)-4-phenyl-2-methylindene; 1,1-bis(methoxymethyl)-4-cyclohexylindene; 1,1-bis(methoxymethyl)-7-(3,3,3-trifluoropropyl)indene; 1,1-bis(methoxymethyl)-7-trimethylsilylindene; 1,1-bis(methoxymethyl)-7-trifluoromethylindene; 1,1-bis(methoxymethyl)-4,7-dimethyl-4,5,6,7-tetrahydroindene; 1,1-bis(methoxymethyl)-7-methylindene; 1,1-bis(methoxymethyl)-7-cyclopentylindene; 1,1-bis(methoxymethyl)-7-isopropylindene; 1,1-bis(methoxymethyl)-7-cyclohexylindene; 1,1-bis(methoxymethyl)-7-tert-butylindene; 1,1-bis(methoxymethyl)-7-tert-butyl-2-methylindene; 1,1-bis(methoxymethyl)-7-phenylindene; 1,1-bis(methoxymethyl)-2-phenylindene; 1,1-bis(methoxymethyl)-1H-benzindene; 1,1-bis(methoxymethyl)-1H-2-methylbenzindene; 9,9-bis(methoxymethyl)fluorene; 9,9-bis(methoxymethyl)-2,3,6,7-tetramethylfluorene; 9,9-bis(methoxymethyl)-2,3,4,5,6,7-hexafluorofluorene; 9,9-bis(methoxymethyl)-2,3-benzofluorene; 9,9-bis(methoxymethyl)-2,3,6,7-dibenzofluorene; 9,9-bis(methoxymethyl)-2,7-diisopropylfluorene; 9,9-bis(methoxymethyl)-1,8-dichlorofluorene; 9,9-bis(methoxymethyl)-2,7-dicyclopentylfluorene; 9,9-bis(methoxymethyl)-1,8-difluorofluorene; 9,9-bis(methoxymethyl)-1,2,3,4-tetrahydrofluorene; 9,9-bis(methoxymethyl)-1,2,3,4,5,6,7,8-octahydrofluorene; 9,9-bis(methoxymethyl)-4-tert-butylfluorene.

[0097] It should be noted that the electron donor compound used in the above component (x) can be used alone or in combination of two or more.

[0098] As the halogen atom as the constituent (x), fluorine, chlorine, bromine, iodine or a mixture of these elements can be cited, and chlorine is particularly preferred.

[0099] As the organoaluminum compound as the component (y), for example, trialkylaluminums such as triethylaluminum and tributylaluminum, trienylaluminums such as triisoprenylaluminum, dialkylalkoxyaluminums such as diethylethoxyaluminum and dibutylbutoxyaluminum, alkyl sesquialkoxyaluminums such as ethyl sesquialethoxyaluminum and butyl sesquialbutoxyaluminum, partial alkoxylated alkylaluminums having an average composition represented by R 1 2.5 Al(OR 2 ) 0.5 (R 1 , R 2 are hydrocarbon groups which may be the same or different from each other), partially halogenated alkylaluminums such as dialkylhaloaluminums such as diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide, alkyl sesquihaloaluminums such as ethyl sesquichloride, butyl sesquichloride, ethyl sesquibromide, alkyl dihaloaluminums such as ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromide, partially hydrogenated alkylaluminums such as dialkylaluminum hydrides such as diethylaluminum hydride and dibutylaluminum hydride, alkylaluminum dihydrides such as ethylaluminum dihydride and propylaluminum dihydride, and partially alkoxylated and halogenated alkylaluminums such as ethyl ethoxychloride, butyl butoxychloride, ethyl ethoxybromide. The above component (y) can be used alone or in combination of two or more.

[0100] As the external electron donor compound of component (z), an organosilicon compound can be used. As preferred organosilicon compounds, for example, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, tert-butylmethyldimethoxysilane, tert-butylmethyldiethoxysilane, tert-pentylmethyldiethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, diphenyldiethoxysilane, bis(o-tolyl)dimethoxysilane, bis(m-tolyl)dimethoxysilane, bis(p-tolyl)dimethoxysilane, bis(p-tolyl)diethoxysilane, bis(ethylphenyl)dimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylmethyldiethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, tert-butyltriethoxysilane, tert-hexyltrimethoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, phenyltriethoxysilane, γ-aminopropyltriethoxysilane, chlorotriethoxysilane, ethyltriisopropoxysilane, vinyltributoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, 2-norbornanetrimethoxysilane, 2-norbornanetriethoxysilane, 2-norbornanemethyldimethoxysilane, tetraethyl orthosilicate, tetrabutyl orthosilicate, trimethylphenoxysilane, methyltriallyloxysilane, vinyltris(β-methoxyethoxysilane), vinyltriacetoxysilane, dimethyltetraethoxydisiloxane, methyl(3,3,3-trifluoro-n-propyl)dimethoxysilane, cyclohexylethyldimethoxysilane, cyclopentyl-tert-butoxydimethoxysilane, diisobutyldimethoxysilane, isobutylisopropyldimethoxysilane, n-propyltrimethoxysilane, di-n-propyldimethoxysilane, tert-butylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butyl-tert-butoxydimethoxysilane, isobutyltrimethoxysilane, cyclohexylisobutyldimethoxysilane, di-sec-butyldimethoxysilane, isobutylmethyldimethoxysilane, bis(decahydroisoquinolin-2-yl)dimethoxysilane, diethylaminotriethoxysilane, dicyclopentyl-bis(ethylamino)silane, tetraethoxysilane, tetramethoxysilane, isobutyltriethoxysilane, tert-butyltrimethoxysilane, isobutyltrimethoxysilane, isobutylsec-butyldimethoxysilane, ethyl(perhydroisoquinolin-2-yl)dimethoxysilane, tris(isopropenyloxy)phenylsilane, isobutylisopropyldimethoxysilane, cyclohexylisobutyldimethoxysilane, cyclopentylisobutyldimethoxysilane, cyclopentylisopropyldimethoxysilane, phenyltriethoxysilane, p-tolylmethyldimethoxysilane, etc. can be cited.

[0101] Among these substances, ethyltriethoxysilane, n-propyltriethoxysilane, n-propyltrimethoxysilane, tert-butyltriethoxysilane, tert-butylmethyldimethoxysilane, tert-butylmethyldiethoxysilane, tert-butylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butyltert-butoxydimethoxysilane, tert-butyltrimethoxysilane, isobutyltrimethoxysilane, isobutylmethyldimethoxysilane, isobutylsec-butyldimethoxysilane, ethyl(perhydroisoquinolin-2-yl)dimethoxysilane, bis(decahydroisoquinolin-2-yl)dimethoxysilane, tris(isopropenyloxy)phenylsilane, tert-hexyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltributoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, isobutylisopropyldimethoxysilane, cyclopentyltert-butoxydimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylisobutyldimethoxysilane, cyclopentylisobutyldimethoxysilane, cyclopentylisopropyldimethoxysilane, di-sec-butyldimethoxysilane, diethylaminotriethoxysilane, tetraethoxysilane, tetramethoxysilane, isobutyltriethoxysilane, phenylmethyldimethoxysilane, phenyltriethoxysilane, bis(p-tolyl)dimethoxysilane, p-tolylmethyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylethyldimethoxysilane, 2-norbornanetriaethoxysilane, 2-norbornanemethyldimethoxysilane, diphenyldiethoxysilane, methyl(3,3,3-trifluoro-n-propyl)dimethoxysilane, ethyl silicate, etc. are preferred. The above component (z) can be used alone or in combination of two or more.

[0102] The organosilicon compound is particularly crucial for regulating the content of xylene-insoluble components. Under the condition that other catalyst components are the same, the content of xylene-insoluble components depends on the type, dosage and polymerization temperature of the organosilicon compound. However, even when using a suitable organosilicon compound, usually except for the diether catalyst, when the dosage of the organosilicon compound is lower than a specific value, this content will decrease significantly. Therefore, when the polymerization temperature is 75 °C, the lower limit of the molar ratio of the organosilicon compound to the organoaluminum compound (organosilicon compound / organoaluminum) is preferably 0.015, more preferably 0.018. The upper limit of this ratio is preferably 0.30, more preferably 0.20, and further preferably 0.10. In other words, the preferred ranges can be exemplified as ranges such as 0.015 to 0.30, 0.015 to 0.20, 0.015 to 0.10, 0.018 to 0.30, 0.018 to 0.20, 0.018 to 0.10, etc.

[0103] When a phthalate compound is used as the internal electron donor compound, increasing the polymerization temperature will cause an increase in the xylene-insoluble content, so the upper and lower limits of the preferred molar ratio of the organosilicon compound to the organoaluminum compound (organosilicon compound / organoaluminum) decrease. Specifically, when using a phthalate compound for polymerization at 80 °C, the lower limit of the molar ratio is preferably 0.010, more preferably 0.015, and further preferably 0.018. The upper limit of the molar ratio is preferably 0.20, more preferably 0.14, and further preferably 0.08. In other words, the preferred ranges can be exemplified as ranges such as 0.010 to 0.20, 0.010 to 0.14, 0.010 to 0.08, 0.015 to 0.20, 0.015 to 0.14, 0.015 to 0.08, 0.018 to 0.20, 0.018 to 0.14, 0.018 to 0.08, etc.

[0104] As the catalyst (X), preferably, the component (y) is a trialkylaluminum such as triethylaluminum or triisobutylaluminum, and the component (z) is an organosilicon compound such as dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, or diisopropyldimethoxysilane.

[0105] The method for obtaining the polymerization mixture by a multi-stage polymerization method is not limited to the above method. An acrylonitrile polymer (component (a1)) can be prepared using multiple polymerization reactors, or an ethylene-α-olefin copolymer (component (a2)) can be prepared using multiple polymerization reactors. As a method for obtaining the polymerization mixture, a method using a polymerization reactor having a gradient of monomer concentration and polymerization conditions can also be cited. In such a polymerization reactor, for example, a polymerization reactor connected with at least 2 polymerization zones can be used, and monomers are polymerized by gas-phase polymerization. Specifically, in the presence of a catalyst, monomers are supplied for polymerization in a polymerization zone composed of a riser tube, and monomers are supplied for polymerization in a downcomer connected to the riser tube. While circulating in the riser tube and the downcomer, the polymerization product is recovered. This method has means to prevent, in whole or in part, the gas mixture present in the riser tube from entering the downcomer. In addition, a gas or liquid mixture having a composition different from that of the gas mixture present in the riser tube is introduced into the downcomer. Such a polymerization method can be applied, for example, to the method described in Japanese Patent Application Laid-Open No. 2002-520426.

[0106] (Method for manufacturing ethylene-α-olefin copolymer (B))

[0107] The ethylene-α-olefin copolymer (B) can be manufactured by a known method (for example, the method described in WO2006 / 102155) using a metallocene catalyst or a semi-metallocene catalyst during polymerization. A known molecular weight regulator such as a chain transfer agent (for example, hydrogen or diethylzinc) can also be used during polymerization.

[0108] 3. Film

[0109] The film is formed from the polypropylene resin composition. The film can be manufactured, for example, by a casting molding method. For example, it is carried out at a molding temperature of 150 to 350°C, preferably 170 to 250°C.

[0110] The thickness of the film can be set, for example, to 0.001 mm to 0.1 mm, preferably 0.01 to 0.09 mm, more preferably 0.03 to 0.09 mm. The thickness of the film molded body can be measured by a known non-contact measurement method such as a beta-ray thickness gauge.

[0111] Even after the film is immersed in the electrolytic solution, the bonding strength of the fusion-bonded part based on thermocompression bonding (sealing strength after immersion in the electrolytic solution) is excellent. Therefore, it is suitable as a packaging material for a battery, that is, a packaging material. This film is particularly suitable as a packaging material for an electrode laminate of a lithium-ion secondary battery. This is because in the manufacturing process of a lithium-ion secondary battery, it is premised that the packaging material comes into contact with the electrolytic solution.

[0112] 4. Packaging Material for Battery

[0113] Figure 1 In this case, as an example of a battery packaging material, a method of packaging a battery electrode laminate in a lithium-ion secondary battery with a packaging material is shown. In the figure, 1 is a packaging material, which includes the polypropylene resin composition film of the present embodiment and other films. 3 is a lithium-ion secondary battery, 5 is a space for accommodating the battery, 7 is a first sealing part, 9 is a second sealing part, and 34 is an electrolytic solution. As shown in the figure, the battery 3 is inserted into the folded packaging material 1, and then the side is heat-sealed to form the first sealing part 7. Then, the electrolytic solution 34 is inserted into the packaging material 1 with an open top. At this time, the packaging material 1 comes into contact with the electrolytic solution 34. After that, the top is heat-sealed to form the second sealing part 9. Therefore, the packaging material 1 is required to have excellent heat-sealing performance even after coming into contact with the electrolytic solution 34.

[0114] Figure 2 A method of the packaging material 1 is shown in the figure. In the figure, 3 is a lithium-ion secondary battery, which is packaged by the packaging material 1. An electrolytic solution 34 (not shown) is filled between the battery 3 and the packaging material 1. In the figure, 31 is a separator, 32 is a negative electrode, and 33 is a positive electrode. Figure 2The structure of the packaging material 1 is shown within the dashed line circle. 13 is a barrier layer, typically made of a metal such as aluminum. 11 is a base material layer, located on the outermost surface side (the side opposite to the battery). The base material layer 11 is usually made of a polymer such as PET or polyamide. S1 is the first sealing layer, made of a material with excellent heat-sealing properties. For example, the first sealing layer is made of the polymer described in Japanese Patent Application Laid-Open No. 2022-35994. S2 is the second sealing layer, and S3 is the third sealing layer. Among them, the second sealing layer S2 or the third sealing layer S3 is preferred, and particularly preferably, the second sealing layer S2 is made of a film formed from the polypropylene resin composition of the present embodiment. For the sake of simplicity in description, the adhesive layer present between each layer is omitted.

[0115] The packaging material having a film formed from the polypropylene resin composition can impart excellent heat-sealing properties even after coming into contact with the electrolyte. This mechanism is not limited, and the following mechanism can be considered. When manufacturing a lithium-ion secondary battery, the first sealing layer S1 comes into contact with the electrolyte. If this state is maintained, the heat-sealing properties of the first sealing layer S1 will decrease. However, the electrolyte will penetrate into the second sealing layer S2. Since the film constituting this layer contains the component (a2) as a rubber component, it will absorb and retain the penetrated electrolyte. As a result, the amount of electrolyte present in the first sealing layer S is extremely small or completely absent. Therefore, it is considered that the heat-sealing properties of the packaging material 1 will not be impaired. And, as described above, when heat-sealing the laminates formed by overlapping multiple films with each other, if an external force is applied to peel the heat seal, material breakage usually occurs at the intermediate layer of the sealing layer composed of three layers, that is, the second sealing layer S2. However, when the second sealing layer S2 is made of the polypropylene resin composition of the present embodiment, material breakage of this layer is not likely to occur, so the sealing strength can be improved.

[0116] Moreover, a space 5 is provided on the packaging material by means of die stamping or the like. At this time, if the bent portion turns white, the reliability will be impaired. In this regard, the film has excellent whitening resistance. In other words, the film of the present embodiment exhibits excellent balance in weldability, electrolyte resistance, and whitening resistance.

[0117] Examples

[0118] <Copolymer 1>

[0119] According to the method described in lines 46 to 53 of Example 5 of European Patent No. 728769, a solid catalyst in which TiCl4 and diisobutyl phthalate as an internal electron donor are supported on MgCl2 was prepared. The specific steps are as follows.

[0120] The following is the preparation of micro long spherical MgCl₂·2.1C₂H₅OH. In a 2 L autoclave equipped with a turbine stirrer and a suction tube, 48 g of anhydrous MgCl₂, 77 g of anhydrous ethanol, and 830 mL of kerosene were added under an inert gas atmosphere and at room temperature. While stirring the contents, it was heated to 120 °C, whereby an adduct between MgCl₂ and the alcohol was formed, but this adduct was melted and mixed with a dispersant. The nitrogen pressure in the autoclave was maintained at 15 atmospheres. The suction tube of the autoclave was heated from the outside to 120 °C using a heating jacket. The inner diameter of this suction tube was 1 mm, and the length of the heating jacket from one end to the other was 3 m. The mixture was made to flow through this tube at a speed of 7 m / sec. At the outlet of the tube, it was collected while stirring the dispersion liquid in a 5 L flask containing 2.5 L of kerosene and cooled from the outside using a jacket with an initial temperature maintained at -40 °C. The final temperature of the dispersion liquid was 0 °C. The spherical solid products constituting the dispersed phase of the emulsion were allowed to settle, filtered and separated, washed with heptane and dried. All these operations were carried out under an inert gas atmosphere. Solid spherical particles of MgCl₂·3C₂H₅OH with a maximum diameter of 50 μm or less were obtained. The yield was 130 g. The product thus obtained was heated stepwise from 50 °C to 100 °C in a nitrogen stream to remove the alcohol until the alcohol content per mole of MgCl₂ decreased to 2.1 moles.

[0121] In a 500 mL cylindrical glass reactor equipped with a filtration barrier, 225 mL of TiCl₄ was added at 0 °C, and while further stirring the contents, 10.1 g (54 mmol) of the micro long spherical MgCl₂·2.1C₂H₅OH obtained as described above was added over 15 minutes. Then the temperature was raised to 40 °C, and 9 mmol of diisobutyl phthalate was added. The temperature was raised to 100 °C over 1 hour and further stirring was continued for 2 hours. Subsequently, TiCl₄ was removed by filtration, and 200 mL of TiCl₄ was added while further stirring at 120 °C for 1 hour. Finally, the contents were filtered and washed with n-heptane at 60 °C until the chloride ions completely disappeared from the filtrate. The catalyst component thus obtained contained Ti = 3.3 mass%, and diisobutyl phthalate = 8.2 mass%.

[0122] Subsequently, using the above solid catalyst, triethylaluminum (TEAL) as an organoaluminum compound, and dicyclopentyldimethoxysilane (DCPMS) as an external electron donor compound, they were contacted at 12 °C for 24 minutes in amounts such that the mass ratio of TEAL to the solid catalyst was 20 and the mass ratio of TEAL / DCPMS was 10 (converted to a molar ratio of the above organosilicon compound / organoaluminum of 0.05). The resulting catalyst (X) was maintained in a suspended state in liquid propylene at 20 °C for 5 minutes, thereby performing prepolymerization. The obtained prepolymer was introduced into the first-stage polymerization reactor of a polymerization apparatus equipped with two-stage polymerization reactors in series, and propylene and ethylene were supplied to prepare a propylene-ethylene copolymer. Subsequently, a propylene-ethylene copolymer, propylene, and ethylene were supplied to the second-stage polymerization reactor to prepare an ethylene-propylene copolymer. During the polymerization, the temperature and pressure were adjusted, and hydrogen was used as a molecular weight regulator.

[0123] Regarding the polymerization temperature and the ratio of the reactants, in the first-stage reactor, the polymerization temperature, hydrogen concentration, and ethylene concentration were 70 °C, 1.84 mol%, and 1.07 mol%, respectively. In the second-stage reactor, the polymerization temperature, hydrogen concentration, and the ratio of ethylene to the total amount of ethylene and propylene were 80 °C, 1.33 mol%, and 0.25 molar ratio, respectively. In addition, the polymerization times of the first stage and the second stage were adjusted so that the content of the ethylene-propylene copolymer reached 32% by mass. By the above method, the target copolymer 1 was obtained.

[0124] The obtained copolymer 1 is a polymerization mixture of a propylene polymer (component (a1)) constituting the continuous phase and an ethylene-propylene copolymer (component (a2)) constituting the rubber phase, and is the above polypropylene resin (A). The physical properties of copolymer 1 are shown in Table 1. In Table 1, "Pht" represents a catalyst containing a phthalate compound as an internal electron donor compound, and "Suc" represents a catalyst containing a succinate compound as an internal electron donor compound. The catalyst (X) obtained by the above method is recorded as "Pht-1" in Table 1.

[0125] <Copolymers 2 to 4>

[0126] Ethylene was not introduced into the first-stage reactor, and the polymerization times of the first stage and the second stage were changed so that the mass ratio of component (a2) / [component (a1) + component (a2)] reached the ratio recorded in Table 1, and the hydrogen concentration in the first stage was adjusted to adjust the MFR of component (a1) + component (a2). Regarding copolymer 3, the ratio of ethylene to the total amount of ethylene and propylene in the second-stage reactor was further changed so that the content of ethylene-derived units in component (a2) reached the ratio recorded in Table 1. Except for the above, copolymers 2 to 4 were obtained by the same preparation method as in the case of copolymer 1.

[0127] <Copolymer 5>

[0128] Adjust the ethylene concentration in the first-stage reactor so that the content of the ethylene-derived unit of component (a1) reaches the ratio described in Table 1, and adjust the hydrogen concentration in the first stage so that the MFR of component (a1) + component (a2) reaches the value described in Table 1. In addition, copolymer 5 is obtained by using the same production method as copolymer 1.

[0129] <Copolymer 6>

[0130] A solid catalyst in which Ti and diisobutyl phthalate as an internal electron donor are supported on MgCl₂ is prepared according to the method described in lines 21 - 36 of paragraph 0032 of JP-A-2004-27218. The specific procedure is as follows.

[0131] Under a nitrogen atmosphere, 56.8 g of anhydrous magnesium chloride is completely dissolved in 100 g of anhydrous ethanol, 500 mL of Vaseline oil "CP15N" produced by Idemitsu Kosan Co., Ltd., and 500 mL of silicone oil "KF96" produced by Shin-Etsu Chemical Co., Ltd. at 120°C. Using a TK homogenizer manufactured by Tokushu Kika Kogyo Co., Ltd., the solution is stirred at 120°C and 5000 revolutions per minute for 2 minutes. While maintaining stirring, it is poured into 2 L of anhydrous heptane in such a manner that the temperature does not exceed 0°C. The resulting white solid is thoroughly washed with anhydrous heptane, vacuum-dried at room temperature, and further partially de-ethanolized under a nitrogen stream to obtain 30 g of spherical solid MgCl₂·1.2C₂H₅OH. The above 30 g of spherical solid is suspended in 200 mL of anhydrous heptane. While stirring at 0°C, 500 mL of titanium tetrachloride is added dropwise over 1 hour. Subsequently, heating is started, and when the temperature reaches 40°C, 4.96 g of diisobutyl phthalate is added, and the temperature is raised to 100°C over about 1 hour. After reacting at 100°C for 2 hours, the solid component is collected by hot filtration. Thereafter, 500 mL of titanium tetrachloride is added to the reaction product, and after stirring, the reaction is carried out at 120°C for 1 hour. After the reaction is completed, the solid component is collected again by hot filtration, and washed 7 times with 1.0 L of hexane at 60°C and 3 times with 1.0 L of hexane at room temperature to obtain a solid catalyst. The titanium content in the obtained solid catalyst is measured, and the result is 2.36% by mass. Except for using the above solid catalyst, copolymer 6 described in Table 1 is obtained by using the same production method as copolymer 1. Among them, ethylene is not introduced into the first-stage reactor, the hydrogen concentration is changed to 0.11 mol%, and the polymerization time of the first stage and the second stage is adjusted so that the mass ratio of component (a2) / [component (a1) + component (a2)] reaches 28% by mass.

[0132] The catalyst (X) obtained by contacting the catalyst prepared by the above method with TEAL and DCPMS is marked as "Pht-2" in Table 1.

[0133] <Copolymer 7>

[0134] Change the hydrogen concentration in the second-stage reactor and the ratio of ethylene to the total amount of ethylene and propylene so that the XSIV of component (a1) + component (a2) and the content of ethylene-derived units in component (a2) reach the values described in Table 1. Also, change the polymerization times of the first and second stages so that the mass ratio of component (a2) / [component (a1) + component (a2)] reaches the ratio described in Table 1, and adjust the hydrogen concentration in the first stage to change the MFR of component (a1) + component (a2) to the value shown in Table 1. Other than this, Copolymer 7 is obtained using the same preparation method as in the case of Copolymer 6.

[0135] <Copolymers 8 - 9>

[0136] Adjust the ratio of ethylene to the total amount of ethylene and propylene in the second-stage reactor so that the content of ethylene-derived units in component (a2) reaches the ratio described in Table 1. Other than this, Copolymers 8 - 9 are obtained using the same preparation method as in the case of Copolymer 3.

[0137] <Copolymers 10 - 11>

[0138] Do not introduce ethylene into the first-stage reactor, change the hydrogen concentration in the second-stage reactor so that the XSIV of component (a1) + component (a2) reaches the value described in Table 1, and adjust the hydrogen concentration in the first stage to adjust the MFR of component (a1) + component (a2). Other than this, Copolymers 10 - 11 are obtained using the same preparation method as in the case of Copolymer 1.

[0139] <Copolymer 12>

[0140] Do not introduce ethylene into the first-stage reactor, adjust the hydrogen concentration in the first stage so that the MFR of component (a1) + component (a2) reaches the value described in Table 1. Other than this, Copolymer 12 is obtained using the same preparation method as in the case of Copolymer 1.

[0141] <Copolymer 13>

[0142] Adjust the hydrogen concentration in the first stage so that the MFR of component (a1) + component (a2) reaches the value described in Table 1. Other than this, Copolymer 13 is obtained using the same preparation method as in the case of Copolymer 1.

[0143] <Copolymer 14>

[0144] According to the preparation method described in the examples of Japanese Patent Application Laid-Open No. 2011-500907, a solid catalyst was prepared through the following steps. In a 500 mL four-necked round-bottom flask purged with nitrogen, 250 mL of TiCl4 was introduced at 0 °C. While stirring, 10.0 g of fine spherical MgCl2·1.8C2H5OH and 9.1 mmol of diethyl 2,3-(diisopropyl)succinate were added. In addition, MgCl2·1.8C2H5OH was manufactured according to the method described in Example 2 of U.S. Patent No. 4,399,054, where instead of 10,000 rpm, it was run at 3,000 rpm. The temperature was raised to 100 °C and maintained for 120 minutes, then stirring was stopped, and the solid product was allowed to settle, and the supernatant was aspirated. Next, the following operation was repeated twice.

[0145] 250 mL of fresh TiCl4 was added, and the mixture was reacted at 120 °C for 60 minutes, and the supernatant was aspirated. The solid was washed 6 times with anhydrous hexane (6 × 100 mL) at 60 °C.

[0146] The above solid catalyst was contacted with TEAL and DCPMS at room temperature for 5 minutes in an amount such that the mass ratio of TEAL to the solid catalyst was 18 and the mass ratio of TEAL / DCPMS was 10. The obtained catalyst was kept in liquid propylene in a suspended state at 20 °C for 5 minutes, thereby performing prepolymerization. The obtained prepolymer was introduced into the first-stage polymerization reactor of a polymerization apparatus equipped with two-stage polymerization reactors in series, and propylene was supplied to prepare a propylene homopolymer. Thereafter, a propylene homopolymer, propylene, and ethylene were supplied to the second-stage polymerization reactor to prepare an ethylene-propylene copolymer. During polymerization, the temperature and pressure were adjusted, and hydrogen was used as a molecular weight regulator. For the polymerization temperature and the ratio of reactants, in the first-stage reactor, the polymerization temperature and hydrogen concentration were 80 °C and 0.14 mol%, respectively, and in the second-stage reactor, the polymerization temperature, hydrogen concentration, and the ratio of ethylene to the total amount of ethylene and propylene were 80 °C, 1.33 mol%, and 0.25 molar ratio, respectively. In addition, the polymerization times of the first stage and the second stage were adjusted so that the content of the ethylene-propylene copolymer reached 32% by mass. Through the above method, the target copolymer 14 was obtained.

[0147] The physical properties of the copolymers 2 to 14 obtained above are shown in Table 1.

[0148] [Table 1]

[0149]

[0150] Each measured value in Table 1 was measured by the following method.

[0151] <Mw / Mn of Component (a1)>

[0152] A 2.5 g sample obtained by collecting the component (a1) polymerized in the first-stage reactor was used as a measurement sample, and the number-average molecular weight (Mn) and weight-average molecular weight (Mw) were measured as follows. The molecular weight distribution (Mw / Mn) was obtained by dividing the weight-average molecular weight (Mw) by the number-average molecular weight (Mn).

[0153] PL GPC220 manufactured by Polymer Laboratories was used as the apparatus, 1,2,4-trichlorobenzene containing an antioxidant was used as the mobile phase, a chromatographic column in which UT-G (1 piece), UT-807 (1 piece), and UT-806M (2 pieces) manufactured by Showa Denko K.K. were connected in series was used as the chromatographic column, and a differential refractive index detector was used as the detector. Also, the same solvent as the mobile phase was used as the solvent for the sample solution, and the measurement sample was prepared by oscillating and dissolving at a sample concentration of 1 mg / mL at a temperature of 150 °C for 2 hours. 500 μL of the sample solution thus obtained was injected into the chromatographic column, and measurement was carried out under the conditions of a flow rate of 1.0 mL / minute, a temperature of 145 °C, and a data acquisition interval of 1 second. A polystyrene standard sample (Shodex STANDARD, manufactured by Showa Denko K.K.) with a molecular weight of 5.8 million to 7.45 million was used, and the chromatographic column was calibrated by cubic approximation. For the Mark-Houwink-Sakurada coefficients, for the polystyrene standard sample, K = 1.21×10 -4 and α = 0.707 were used, and for polypropylene homopolymers, propylene random copolymers, and polypropylene-based copolymers, K = 1.37×10 -4 and α = 0.75 were used.

[0154] <Total ethylene content of the copolymer, content of ethylene-derived units of component (a1)>

[0155] For the copolymer sample dissolved in a mixed solvent of 1,2,4-trichlorobenzene / deuterated benzene, AVANCE III HD400 manufactured by Bruker ( 13 13C resonance frequency 100 MHz) was used, and the 13C-NMR spectrum was obtained under the conditions of a measurement temperature of 120 °C, a flip angle of 45 degrees, a pulse interval of 7 seconds, a sample rotation speed of 20 Hz, and a cumulative number of 5000 times. 13 13C-NMR spectrum.

[0156] Using the spectrum obtained above, the total ethylene content (mass %) in the copolymer was determined by the method described in the literature of Kakugo, Y., Naito, K., Mizunuma, K. and Miyatake, T., Macromolecules, 15, 1150 - 1152 (1982). It should be noted that when the component (a1) was used as the sample for measurement, the total ethylene content (mass %) obtained by the above method was the ethylene unit content (mass %) of the component (a1).

[0157] <Ethylene unit content of component (a2)>

[0158] When measuring the total ethylene content of the copolymer by the method described in the above literature, the integral intensity T'ββ obtained by the following formula was used to replace the obtained integral intensity Tββ. Except for this, the calculation was carried out by the same method as for the total ethylene content to obtain the ethylene unit content (mass %) of the component (a2).

[0159] T’ββ = 0.98 × Sαγ × A / (1 - 0.98 × A)

[0160] Here, A = Sαγ / (Sαγ + Sαδ), which was calculated based on Sαγ and Sαδ described in the above literature.

[0161] It should be noted that in the copolymer composed of the component (a1) and the component (a2), for the content of the ethylene - derived unit in the component (a2) containing ethylene units in the component (a1), when the mass ratio (component (a2) / [component (a1) + component (a2)]) can be determined by the polymerization conditions (corresponding to the copolymers 1, 5 and 13), it was obtained by the following formula.

[0162] Content of ethylene - derived unit of component (a2) (unit: mass %) =

[0163] [Total ethylene content of the copolymer - content ratio of component (a1) in the copolymer × ethylene - derived unit content of component (a1)] / (content ratio of component (a2) in the copolymer)

[0164] <Mass ratio component (a2) / [component (a1) + component (a2)]>

[0165] It was obtained by the following formula.

[0166] Component (a2) / [component (a1) + component (a2)] (unit: mass %) = total ethylene content of the copolymer / (ethylene unit content in component (a2) / 100)

[0167] <XSIV of component (a1) + component (a2)>

[0168] The xylene-soluble component of the copolymer was obtained by the following method, and the intrinsic viscosity (XSIV) of the xylene-soluble component was measured.

[0169] A 2.5 g copolymer sample was placed in a flask containing 250 mL of o-xylene (solvent). Using a heating plate and a reflux device, while purging with nitrogen at 135 °C, it was stirred for 30 minutes until completely dissolved, and then cooled at 25 °C for 1 hour. The resulting solution was filtered using filter paper. 100 mL of the filtered filtrate was collected, transferred to an aluminum cup, etc., and evaporated to dryness at 140 °C while purging with nitrogen, and left standing at room temperature for 30 minutes to obtain the xylene-soluble component.

[0170] The measurement of the intrinsic viscosity was carried out in tetralin at 135 °C using a capillary viscometer (SS-780-H1, manufactured by Shibayama Scientific Instruments Co., Ltd.).

[0171] <MFR of component (a1) + component (a2)>

[0172] 0.05 g of H-BHT manufactured by Honshu Chemical Industry Co., Ltd. was added to 5 g of the copolymer sample, and after homogenizing by dry mixing, the measurement was carried out according to JIS K7210-1 and based on JIS K6921-2 under the conditions of a temperature of 230 °C and a load of 2.16 kg.

[0173] [Example 1]

[0174] 0.2 parts by mass of B225 manufactured by BASF as an antioxidant and 0.05 parts by mass of calcium stearate manufactured by Tannan Chemical Industry Co., Ltd. as a neutralizer were added to Copolymer 1, and the mixture was stirred and mixed for 1 minute using a Henschel mixer. The mixture was melt-kneaded and extruded using a co-rotating twin-screw extruder TEX-30α manufactured by JSW Co., Ltd. at a barrel temperature of 230 °C. After cooling the strand in water, it was cut by a granulator to obtain a granular Copolymer 1 composition.

[0175] The following substances were prepared as polymers for a three-layer film having three sealing layers.

[0176] The first sealing layer

[0177] C-1: A blend of an ethylene-propylene random copolymer (MFR = 10 g / 10 min, melting point = 123 °C, Mw / Mn = 3.5) and polyethylene (blending mass ratio 86:14)

[0178] The second sealing layer

[0179] The Copolymer 1 composition prepared as described above

[0180] The third sealing layer

[0181] D-1: Ethylene-propylene random copolymer (MFR = 10 g / 10 min, melting point = 123 °C, Mw / Mn = 3.5)

[0182] Using a 3-layer φ25 mm film / sheet forming device manufactured by Thermoplastics Industries, the temperature from the barrel to the die head was set to 250 °C, and the above compositions and polymers were co-extruded. The molten resin extruded from the die head was cooled and solidified while being drawn at 5.6 m / min through a cooling roll. As a result, a sealed film sample having the following structure was obtained.

[0183] The first sealing layer: thickness 6 μm

[0184] The second sealing layer: thickness 28 μm

[0185] The third sealing layer: thickness 6 μm

[0186] Total thickness: 40 μm

[0187] The sealed film sample was subjected to an aging treatment at 40 °C for 24 hours or more, and further conditioned at a constant temperature of 23 °C for 1 hour or more. On the other hand, a 2-layer film was prepared by bonding biaxially stretched 6-nylon with a thickness of 25 μm as a base material layer and an aluminum foil with a thickness of 35 μm as a barrier layer. The 2-layer film was bonded to the above sealed film sample with the barrier layer facing the third sealing layer using an adhesive. As the adhesive, a two-component curable maleic acid-modified propylene adhesive was used. This sample was evaluated by the method described below.

[0188] [Examples 2, 3, 5, 6 and Comparative Examples 1-8]

[0189] Using the copolymers shown in Table 2 to replace Copolymer 1, except for this, the packaging film samples were manufactured and evaluated in the same manner as in Example 1.

[0190] [Example 4]

[0191] Ethylene-butene copolymer (Tafmer A4085 manufactured by Mitsui Chemicals, MFR (190 °C, 2.16 kg) = 3.6 g / 10 min) was prepared as component (B). Using Copolymer 4 to replace Copolymer 1, except for this, the Copolymer 4 composition was obtained in the same manner as in Example 1. The ethylene-butene copolymer and the Copolymer 4 composition were dry-blended. The dry blend was supplied as the second sealing polymer to the extruder, and except for this, the packaging film samples were manufactured and evaluated in the same manner as in Example 1. These results are shown in Table 2.

[0192]

[0193] Obviously, the packaging film samples obtained through the examples are suitable as battery packaging materials.

[0194] [Evaluation method]

[0195] <PP plant productivity>

[0196] When manufacturing component (A) using the above method, the degree of difficulty is evaluated according to the following 4 levels.

[0197] "A": Excellent = Completely no problem, can be manufactured.

[0198] "B": Good = No problem, can be manufactured.

[0199] "C": Passable = Can be manufactured, but the yield and fluff properties are slightly poor.

[0200] "D": Not feasible = Problems occur during manufacturing and cannot be manufactured.

[0201] <Flowability MFR>

[0202] For the MFR of polypropylene resin compositions and dry blends of polypropylene resin compositions and ethylene-α-olefin copolymers, it is measured according to JIS K7210-1 and based on JIS K6921-2 under the conditions of a temperature of 230 °C and a load of 2.16 kg.

[0203] For the MFR of ethylene-α-olefin copolymers, it is measured based on JIS K6922-2 under the conditions of a temperature of 190 °C and a load of 2.16 kg.

[0204] <Electrolyte immersion treatment>

[0205] Immerse the sample in the electrolyte at 85 °C for 3 days. As the electrolyte, use a solution prepared by dissolving lithium hexafluorophosphate salt at a concentration of 1 mol / L in a mixed solvent obtained by mixing ethylene carbonate and diethyl carbonate in a volume ratio of 1:1.

[0206] <Sealing strength>

[0207] According to JIS Z0238, specimens were formed by heat-sealing between packaging film samples, and the sealing strength of the specimens was tested. First, the surfaces of the first sealing layers of two film samples that had not been immersed in the electrolyte were placed opposite to each other, and the laminate was sandwiched between a pair of aluminum sealing strips adjusted to the set temperature in a heat-sealing tester (manufactured by Tester Industries, Inc.). Heat pressing was performed at a gauge pressure of 0.2 MPa and a temperature of 180°C for 3 seconds. The sample was taken out and slowly cooled at room temperature to obtain a sample in which only the portion welded by the heat of the sealing strip was sealed. The sample was cut to a width of 15 mm. Using Autocom (manufactured by T.S.E. Corporation), a pair of film pieces connected at the sealed portion were stretched in opposite directions (stretching speed: 100 mm / minute), and the strength (unit: N / 15 mm) at the time of peeling or breaking of the sealed portion was measured as the sealing strength. Then, for the packaging film samples that had been immersed in the electrolyte, two packaging film samples taken out of the electrolyte were immediately subjected to the above test, and the sealing strength was evaluated in the same manner.

[0208] <Whitening resistance>

[0209] Using a deep drawing die manufactured by AMADA Co., Ltd., the packaging film sample was deep drawn into a rectangular parallelepiped shape with a depth of 5 mm. The forming conditions were as follows. The inner surface (three surfaces of the inner sealing layer) of the storage recess of the obtained formed body was visually observed, and the presence and degree of whitening were evaluated according to the following four levels.

[0210] "A": Excellent: No whitening was observed or there was basically no whitening.

[0211] "B": Good: Little whitening.

[0212] "C": Passable: Whitening occurred to a certain extent.

[0213] "D": Unacceptable: Significant whitening occurred.

[0214] (Forming conditions)

[0215] Forming die

[0216] Punch: 33.3 mm × 53.9 mm, Die: 80 mm × 120 mm, Corner R: 2 mm, Punch R: 1.3 mm, Die R: 1 mm Anti-wrinkle pressure

[0217] Gauge pressure: 0.475 Mpa, Actual pressure (calculated value): 0.7 MPa

[0218] Material

[0219] SC (carbon steel) material, only the R corner of the punch was chrome-plated

[0220] <Fish eye (FE)>

[0221] For the sealed film samples that have not been immersed in the electrolyte, measure the number of FEs with a size of 0.1 - 0.5 mmφ generated within each reference area, and evaluate them according to the following 4 levels.

[0222] "A": Excellent: 10 pieces / m 2 The following

[0223] "B": Good: 11 - 20 pieces / m 2

[0224] "C": Passable: 21 - 30 pieces / m 2

[0225] "D": Unacceptable: 31 pieces / m 2 The above

[0226] <Film formability>

[0227] For the sealed film samples obtained by the above forming method, evaluate them according to the following 3 levels.

[0228] "A": Good: Obtain qualified products with no problems in shape, thickness, etc.

[0229] "B": Passable: Some defective products are produced.

[0230] "C": Unacceptable: Unable to obtain qualified products.

[0231] <Film productivity>

[0232] When forming the film while suppressing the generation of FEs, from the perspective of the reduction in production speed, evaluate the degree of film productivity according to the following 3 levels.

[0233] "A": No problem, easy to produce.

[0234] "B": Can be formed if special equipment such as a polymer filter is used, but the production speed is reduced.

[0235] "C": The production speed is greatly reduced, and it is difficult to produce the film.

[0236] Symbol description

[0237] 1 Packaging material

[0238] 3 Lithium-ion secondary battery

[0239] 31 Separator

[0240] 32 Negative electrode

[0241] 33 Positive electrode

[0242] 34 Electrolyte

[0243] Space for accommodating the battery

[0244] 7 First sealing portion

[0245] 9 Second sealing portion

[0246] 11 Base material layer

[0247] 13 Barrier layer

[0248] S1 First sealing layer

[0249] S2 Second sealing layer

[0250] S3 Third sealing layer

Claims

1. A polypropylene resin composition for battery packaging materials, which contains: A polypropylene resin (A) comprising a continuous phase composed of a propylene polymer (a1) and a rubber phase composed of a copolymer (a2) of ethylene and an α-olefin having 3 to 10 carbon atoms; and An ethylene-α-olefin copolymer (B) as an optional component, which is a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms, wherein, The content ratio of the polypropylene resin (A) is 90% by mass to 100% by mass of the total mass of the polypropylene resin composition, The content ratio of the ethylene-α-olefin copolymer (B) is 0% by mass to 10% by mass of the total mass of (A) and (B), The MFR of the polypropylene resin composition at a temperature of 230 °C and a load of 2.16 kg is 0.5 g / 10 min to 12.0 g / 10 min, The ratio (Mw / Mn) of the weight-average molecular weight Mw to the number-average molecular weight Mn of the propylene polymer (a1) is less than 8, The content of ethylene-derived units in the propylene polymer (a1) is 7.0% by mass or less of the total mass of the propylene polymer (a1), The content of the copolymer (a2) is 30% by mass to 43% by mass of the total mass of the polypropylene resin (A), The content of ethylene-derived units in the copolymer (a2) is 20% by mass to 40% by mass of the total mass of the copolymer (a2), The limiting viscosity of the xylene-soluble component of the polypropylene resin (A) in tetralin at 135 °C is 2.5 dl / g to 3.5 dl / g, The MFR of the polypropylene resin (A) at a temperature of 230 °C and a load of 2.16 kg is 0.5 g / 10 min to 12.0 g / 10 min.

2. The polypropylene resin composition according to claim 1, wherein, The propylene polymer (a1) and the copolymer (a2) are mixed by polymerization, and the polypropylene resin (A) is a polymerization mixture produced using a catalyst containing the following components (x) to (z), (x) A solid catalyst containing magnesium, titanium, halogen, and a phthalate compound as an electron donor compound (y) An organoaluminum compound (z) An organosilicon compound as an external electron donor compound.

3. The polypropylene resin composition according to claim 1, wherein, The battery is a lithium-ion battery.

4. A film formed by molding the polypropylene resin composition according to claims 1 to 3.

5. A battery packaging material comprising the film according to claim 4.

6. A method for manufacturing a polypropylene resin composition, which is the method for manufacturing the polypropylene resin composition according to claims 1 to 3, wherein, The manufacturing method has the following steps: using a catalyst containing the following components (x) to (z), in the presence of the propylene polymer (a1), polymerizing raw material monomers to obtain the polypropylene resin (A), (x) A solid catalyst containing magnesium, titanium, halogen, and a phthalate compound as an electron donor compound (y) An organoaluminum compound (z) An organosilicon compound as an external electron donor compound.

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