Film, laminate, packaging material, exterior material, and film manufacturing method

Abstract

To provide a film having excellent insulation properties, and a laminate, a packaging material, and an exterior material including the film, and a method for producing the film.SOLUTION: A film contains two or more amide polymers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a film, a laminate, a packaging material, an exterior material, and a method for producing a film. [Background technology]

[0002] Films made of nylon or the like have excellent strength and impact resistance, and therefore, laminated packaging materials containing such films can be suitably used for battery packaging, pharmaceutical packaging (PTP: Press-through pack packaging, etc.), daily necessities (refill packaging for liquid detergent, etc.), food packaging, etc. For example, Patent Document 1 discloses that a laminated packaging material containing a biaxially oriented nylon film made from nylon resin is used as a packaging material for cold forming. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 021425 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when nylon film is used as the exterior material for lithium-ion secondary batteries (LiBs), especially for automotive LiBs, its insulating properties deteriorate due to moisture absorption, and it does not meet the required insulating properties. Furthermore, there is a problem that automobile oil and battery electrolyte adhere to the nylon film, resulting in poor appearance.

[0005] An object of the present invention is to provide a film having excellent insulating properties. Another object of the present invention is to provide a laminate, a packaging material, an exterior material, and a method for producing the film. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a film containing two or more amide-based polymers.

[0007] The film according to one embodiment of the present invention has a specific volume resistivity of 1×10 13 It may be Ω·cm or more.

[0008] The film according to one aspect of the present invention may have a water absorption rate of 10% or less.

[0009] The film according to one aspect of the present invention may have a breakdown voltage of 3 kV or more.

[0010] In the film according to one embodiment of the present invention, at least one of the two or more amide polymers has a volume resistivity of 1×10 14 It may be Ω·cm or more.

[0011] In the film according to one aspect of the present invention, at least one of the two or more amide polymers may have a water absorption rate of 10% or less.

[0012] In the film according to one embodiment of the present invention, at least one of the two or more amide polymers may have a breakdown voltage of 3.1 kV or more.

[0013] In the film according to one embodiment of the present invention, at least one of the two or more amide polymers may be nylon 6.

[0014] In the film according to one aspect of the present invention, the content of nylon 6 in the film may be 1% by mass or more and 70% by mass or less.

[0015] In the film according to one aspect of the present invention, the content of the amide polymer other than nylon 6 in the film may be 30% by mass or more and 99% by mass or less.

[0016] The film according to one embodiment of the present invention may contain an amide polymer represented by the following general formula (1) as the amide polymer other than nylon 6.

[0017] [ka]

[0018] In the general formula (1), A1 is a phenylene group or an alkylene group having 2 to 7 carbon atoms, A2 is a phenylene group or an alkylene group having 4 to 10 carbon atoms, n is an integer from 50 to 1500.

[0019] The film according to one aspect of the present invention may have a thickness of 10 μm or more and 50 μm or less.

[0020] The film according to one embodiment of the present invention has a density of 1.0 g / cm 3 More than 2.0g / cm 3 It may be the following:

[0021] In a film according to one aspect of the present invention, the MD tensile strength of the film may be 150 MPa or more and 500 MPa or less, and the TD tensile strength of the film may be 150 MPa or more and 500 MPa or less.

[0022] According to one aspect of the present invention, there is provided a laminate comprising the film.

[0023] According to one aspect of the present invention, there is provided a packaging material comprising the film.

[0024] According to one aspect of the present invention, there is provided an exterior packaging material comprising the film.

[0025] According to one aspect of the present invention, there is provided an exterior packaging material using the laminate.

[0026] The packaging material according to one aspect of the present invention may be used in a lithium-ion secondary battery.

[0027] According to one aspect of the present invention, there is provided a method for producing the film, which comprises a step of stretching the film by tubular biaxial stretching. [Effects of the Invention]

[0028] According to one aspect of the present invention, a film having excellent insulating properties can be provided. Furthermore, according to one aspect of the present invention, it is possible to provide a laminate, a packaging material, an exterior material, and a method for producing the film, each including the film. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a cross-sectional schematic view of a film according to one embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating an example of an apparatus used in a film manufacturing method according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional schematic view of a laminate according to one embodiment of the present invention. [Figure 4] 1 is a schematic cross-sectional view of a lithium ion secondary battery using an exterior material according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0031] [First embodiment] In the first embodiment, a film, a method for producing the film, a laminate, a packaging material, and an exterior material according to one aspect of the present invention will be described.

[0032] [film] 1 is a schematic cross-sectional view of a film 1 according to this embodiment. The film 1 according to this embodiment may be used as a single layer film, or may be used as at least one layer of a laminate having multiple layers, as described below. The film 1 contains two or more types of amide polymers.

[0033] Amide polymers Examples of the two or more amide polymers contained in film 1 include nylon 6, nylon 8, nylon 9, nylon 10, nylon 11, nylon 12, nylon 4,6, nylon 6,6, nylon 6,10, nylon 6,11, nylon 6,12, nylon 6T, nylon 9T, and metaxylenediamine (MXD) nylon (MXD6). The film 1 may contain two types of amide polymers, or may contain three or more types. These amide polymers do not necessarily have to be derived from fossil fuels, and may be, for example, environmentally friendly plant-derived amide polymers, or a combination of a fossil fuel-derived amide polymer and a plant-derived amide polymer. For example, when film 1 contains two types of amide polymers, both types may be fossil fuel-derived amide polymers, or one of the amide polymers may be a fossil fuel-derived amide polymer and the other a plant-derived amide polymer, or both types may be plant-derived amide polymers.

[0034] Of the two or more amide polymers contained in the film 1, it is preferred that at least one of the amide polymers is nylon 6. When film 1 contains nylon 6, the content of nylon 6 in film 1 is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to the total mass (100% by mass) of the resins contained in film 1. Furthermore, the content of nylon 6 in film 1 is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less, and even more preferably 45% by mass or less, relative to the total mass of the resins contained in film 1. Furthermore, when film 1 contains nylon 6, the content of amide polymers other than nylon 6 in film 1 is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, relative to the total mass of resins contained in film 1. Furthermore, the content of amide polymers other than nylon 6 in film 1 is preferably 99% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, even more preferably 80% by mass or less, and particularly preferably 75% by mass or less, relative to the total mass of resins contained in film 1.

[0035] When the film 1 contains nylon 6, the film 1 preferably contains an amide polymer other than nylon 6, the amide polymer being represented by the following general formula (1).

[0036] [ka]

[0037] In the general formula (1), A1 is a phenylene group or an alkylene group having 2 to 7 carbon atoms. In the general formula (1), A2 is a phenylene group or an alkylene group having 4 to 10 carbon atoms. In the general formula (1), n ​​is an integer of 50 to 1500, and preferably an integer of 100 to 100.

[0038] If the film 1 contains nylon 6 and the amide polymer represented by the general formula (1), the film 1 will have better insulating properties and chemical resistance.

[0039] When film 1 contains nylon 6, the amide polymer other than nylon 6 is preferably at least one of nylon 6,10, nylon 6,12, nylon 6T, nylon 9T, and metaxylenediamine (MXD) nylon (MXD6) from the viewpoint of chemical resistance, and is even more preferably at least one of nylon 9T and nylon 6,12.

[0040] The volume resistivity of at least one of the two or more amide polymers contained in film 1 is 1×10 when measured as a film having a thickness of 25 μm. 14 The upper limit of the volume resistivity of the amide polymer is not particularly limited, but is usually 1×10 18 Ω·cm. The volume resistivity of the amide polymer can be measured in accordance with the measurement method described in the Examples below.

[0041] The water absorption of at least one of the two or more amide polymers contained in the film 1 is preferably 10% or less, more preferably 7% or less, even more preferably 6.3% or less, still more preferably 5% or less, and particularly preferably 4.5% or less. There is no particular lower limit for the water absorption of the amide polymer, but it is usually 0.1%. The water absorption rate of the amide polymer can be measured in accordance with JIS K7209: 2000. Specifically, it can be measured in accordance with the measurement method described in the Examples below.

[0042] The breakdown voltage of at least one of the two or more amide polymers contained in film 1 is preferably 3.1 kV or more when measured as a film having a thickness of 25 μm. There is no particular upper limit to the breakdown voltage of the amide polymer, but it is usually 10 kV. The breakdown voltage of the film can be measured in accordance with the measurement method described in the Examples below.

[0043] The film 1 may contain only an amide-based polymer, or may contain other components in addition to the amide-based polymer. For example, the film 1 may contain a plant-derived resin, in which case at least a part of the amide polymer may be a plant-derived resin. The film 1 contains a plant-derived resin, which reduces the environmental impact.

[0044] For example, the film 1 may also contain additives such as an antiblocking agent, a slip agent, a water repellent agent, an anti-dye agent, an antioxidant, and a neutralizing agent. Furthermore, the film 1 may contain impurities to the extent that the effect of the present invention is not lost.

[0045] Film 1 has a volume resistivity of 1×10 13 It is preferable that the resistance is Ω·cm or more, and 1×10 14 It is more preferable that the resistance is Ω·cm or more, and 1×10 15 It is more preferable that the volume resistivity of the film 1 is Ω·cm or more. If the volume resistivity of the film 1 is in this range, the film 1 has excellent insulating properties. The upper limit of the volume resistivity of film 1 is not particularly limited, but is usually 1×10 18 Ω·cm.

[0046] Film 1 has a volume resistivity of 1×10 when measured as a 25 μm thick film. 13 It is preferable that the resistance is Ω·cm or more, and 1×10 14 It is more preferable that the resistance is Ω·cm or more, and 1×1015 It is more preferable that the volume resistivity of the film 1 is Ω·cm or more. If the volume resistivity of the film 1 is within this range when measured as a film having a thickness of 25 μm, the film 1 has excellent insulating properties. The upper limit of the volume resistivity of film 1 when measured as a 25 μm thick film is not particularly limited, but is usually 1×10 18 Ω·cm.

[0047] The volume resistivity of the film can be measured in accordance with JIS K6911: 1995. Specifically, it can be measured in accordance with the measurement method described in the examples below.

[0048] The water absorption rate of the film 1 is preferably 10% or less, more preferably 8% or less, and even more preferably 6% or less. If the water absorption rate of the film 1 is 10% or less, the film 1 will have better insulating properties. There is no particular limitation on the lower limit of the water absorption rate of the film 1, but it is usually 0.1%. The water absorption rate of the film can be measured in accordance with JIS K7209. Specifically, it can be measured in accordance with the measurement method described in the examples below.

[0049] The breakdown voltage of the film 1 is preferably 3 kV or more, more preferably 3.2 kV or more, and even more preferably 3.5 kV or more. If the breakdown voltage of the film 1 is within this range, the film 1 will have excellent insulating properties. The upper limit of the breakdown voltage of the film 1 is not particularly limited, but is usually 10 kV.

[0050] When measured as a 25 μm thick film, the breakdown voltage of film 1 is preferably 3 kV or more, more preferably 3.2 kV or more, and even more preferably 3.5 kV or more. If the breakdown voltage of film 1 when measured as a 25 μm thick film is within this range, film 1 has excellent insulating properties. The upper limit of the breakdown voltage of the film 1 when measured as a film having a thickness of 25 μm is not particularly limited, but is usually 10 kV.

[0051] The breakdown voltage of the film can be measured in accordance with JIS C2110-1:2016. Specifically, it can be measured in accordance with the measurement method described in the examples below.

[0052] Film 1 has a volume resistivity of 1×10 13 It is preferable that the specific volume resistivity is 1×10 14 It is more preferable that the specific volume resistivity is 1×10 Ω·cm or more, the water absorption rate is 8% or less, and the breakdown voltage is 3.2 kV or more. 15 It is more preferable that the film 1 has a specific volume resistivity of 1×10 Ω·cm or more, a water absorption rate of 6% or less, and a breakdown voltage of 3.5 kV or more. 18 It is preferable that the electrical resistance is Ω·cm or less, the water absorption is 0.1% or more, and the dielectric breakdown voltage is 10 kV or less.

[0053] Film 1 has a density of 1.0 g / cm 3 It is preferable that the concentration is 1.1 g / cm or more. 3 It is more preferable that the density of the film 1 is 1.0 g / cm or more. 3 If this is the case, the film 1 has better insulating properties. The density of Film 1 is 2.0 g / cm 3 It is preferable that the concentration is 1.5 g / cm or less. 3 More preferably, it is: The density of the film can be measured by a He gas substitution method, specifically in accordance with the measurement method described in the Examples below.

[0054] The thickness of the film 1 is not particularly limited. The thickness of the film 1 is appropriately set depending on the application. The thickness of the film 1 is, for example, 7 μm or more, preferably 10 μm or more, and more preferably 12 μm or more. The thickness of the film 1 is, for example, 50 μm or less, preferably 45 μm or less, and more preferably 40 μm or less. If the thickness of the film 1 is 7 μm or more, the film 1 has better insulating properties. If the thickness of the film 1 is 50 μm or less, the manufacturing cost of the film 1 can be reduced.

[0055] The tensile strength of the film 1 in the machine direction (MD) is preferably 150 MPa or more, more preferably 170 MPa or more, and the tensile strength of the film 1 in the MD is preferably 500 MPa or less, more preferably 450 MPa or less. The TD (transverse direction) tensile strength of the film 1 is preferably 150 MPa or more, more preferably 170 MPa or more, and the TD tensile strength of the film 1 is preferably 500 MPa or less, more preferably 450 MPa or less. When the tensile properties (breaking strength) in at least one of the MD and TD of the film 1 are within the above range, the film 1 has excellent formability. If the film 1 has excellent formability, laminates and packaging materials including the film 1 can be easily press-molded. It is more preferable that the MD tensile strength of film 1 is 150 MPa or more, and the TD tensile strength is 150 MPa or more, and it is even more preferable that both have a breaking strength of 170 MPa or more, and it is even more preferable that both have a breaking strength of 500 MPa or less.

[0056] The MD tensile properties of the film 1 are preferably an elongation of 70% or more, more preferably 80% or more, and even more preferably 90% or more, and the MD tensile properties of the film 1 are preferably an elongation of 180% or less, more preferably 170% or less, and even more preferably 160% or less. The TD tensile properties of the film 1 are preferably an elongation of 70% or more, more preferably 80% or more, and even more preferably 90% or more, and the TD tensile properties of the film 1 are preferably an elongation of 180% or less, more preferably 170% or less, and even more preferably 160% or less. When the tensile properties (elongation percentage) of at least one of the MD and TD of the film 1 are within the above range, the film 1 has better formability. It is more preferable that the MD tensile property of the film 1 is an elongation percentage of 70% or more, and the TD tensile property is an elongation percentage of 70% or more, and more preferably both are an elongation percentage of 180% or less.

[0057] The tensile properties (breaking strength and elongation) of the film can be measured in accordance with ASTM D882. Specifically, they can be measured in accordance with the measurement method described in the examples below.

[0058] There are no particular limitations on the method for producing the film 1. The film 1 is preferably a biaxially stretched film. As an example, a method for producing the film 1 including a step of stretching by tubular biaxial stretching will be described below with reference to the drawings.

[0059] [Biaxially stretched film manufacturing equipment] First, an example of an apparatus for producing the biaxially stretched film of this embodiment will be described.

[0060] As shown in FIG. 2, the film manufacturing apparatus 80 includes a raw film manufacturing apparatus 70 for manufacturing the raw film 2, a biaxial stretching apparatus (tubular stretching apparatus) 10 for stretching the raw film 2, a first heat treatment apparatus 20 (preheating furnace) for preheating the base film 3 (hereinafter simply referred to as "film 3") folded after stretching, a separation apparatus 30 for separating the preheated film 3 into two pieces, an upper piece and a lower piece, a second heat treatment apparatus 40 for heat treating (heat setting) the separated film 3, a tension control apparatus 50 for applying tension to the film 3 from the downstream side when the film 3 is heat set, and a winding apparatus 60 for winding up the biaxially stretched film 4 (hereinafter simply referred to as "film 4") obtained by heat setting the film 3.

[0061] As shown in FIG. 2, the raw sheet manufacturing apparatus 70 includes an extruder 71, a circular die 72, a water-cooled ring 73, a stabilizer plate 74, and a pinch roll 75. The tubular stretching device 10 is a device for biaxially stretching (bubble stretching) a tubular raw film 2 using internal air pressure to produce a film 3. As shown in FIG. 2, the tubular stretching device 10 includes a pinch roll 11, a heating section 12, a guide plate 13, and a pinch roll 14.

[0062] The first heat treatment device 20 is a device for preliminarily heat treating the flattened film 3. As shown in FIG.

[0063] 2, the separating device 30 includes a guide roll 31, a trimming device 32, separating rolls 33A and 33B, and grooved rolls 34A, 34B, and 34C. The trimming device 32 also includes a blade 321.

[0064] As shown in FIG. 2, the second heat treatment device 40 includes a tenter 41 and a heating furnace 42. As shown in FIG. 2, the tension control device 50 includes guide rolls 51A and 51B and a tension roll 52. As shown in FIG. 2, the winding device 60 includes a guide roll 61 and a winding roll 62.

[0065] [Manufacturing method of biaxially oriented nylon film] Next, each step of producing a biaxially oriented nylon film using this film production apparatus 80 will be described in detail.

[0066] (raw film manufacturing process) As shown in FIG. 2, the raw material resin containing two or more types of amide polymers is melt-kneaded in an extruder 71 and extruded into a tubular shape by a circular die 72. The tubular molten resin is cooled by a water-cooling ring 73. The raw film 2 is formed by rapidly cooling the raw material molten nylon resin by the water-cooling ring 73. The cooled raw film 2 is folded by a stabilizer plate 74. The folded raw film 2 is sent to the next biaxial stretching process as a flat film by a pinch roll 75.

[0067] (Biaxial stretching process) As shown in Figure 2, raw film 2 produced in the raw film production process is introduced into the device as a flat film by pinch rolls 11. The introduced raw film 2 is bubble-stretched by heating with infrared rays in heating section 12. The bubble-stretched film 3 is then folded by guide plate 13. The folded film 3 is pinched by pinch rolls 14 and sent to the next first heat treatment process as a flat film 3.

[0068] In this case, by setting the MD and TD stretching ratios to 2.8 times or more, respectively, it is expected that the impact strength will be improved. Furthermore, the difference (TD-MD) obtained by subtracting the MD stretching ratio from the TD stretching ratio is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more. Furthermore, the TD-MD value is more preferably 0.8 or less. When the TD-MD value is equal to or greater than the lower limit, the deep drawability of the resulting film tends to be sufficient, and the thickness precision of the film tends to increase. Furthermore, particularly when the TD-MD value is 0.1 or more, the stretching stability is excellent and the thickness precision of the film tends to increase. On the other hand, when the TD-MD value is equal to or less than the upper limit, the deep drawability of the resulting film tends to be sufficient, and the stretching stability tends to increase.

[0069] (First heat treatment process) The film 3 sent from the biaxial stretching process is held at both ends by clips (not shown) of the tenter 21, and is pre-heat-treated at a temperature equal to or higher than the shrinkage initiation temperature of the film 3 and approximately 30°C lower than the melting point of the film 3, before being sent to the next separation process. The heat treatment temperature in this first heat treatment is preferably 120° C. or higher and 190° C. or lower, and the relaxation rate is preferably 15% or lower. This first heat treatment step increases the crystallinity of the film 3, improving the sliding properties between the overlapping films.

[0070] (separation process) As shown in Figure 2, the flat film 3 fed through the guide rolls 31 is cut at both ends by blade 321 of trimming device 32 to separate it into two films 3A and 3B. The films 3A and 3B are then separated by a pair of separation rolls 33A and 33B positioned above and below, with air interposed between them. This cutting of the flat film 3 may be performed by positioning blade 321 slightly inward from both ends to create partial selvages, or by positioning blade 321 at the fold of the film 3 to prevent selvages from being created. These films 3A and 3B are stacked again by three grooved rolls 34A, 34B, and 34C positioned in the direction of film flow, and sent to the next, second heat treatment step. These grooved rolls 34A, 34B, and 34C are plated after being grooved. These grooves ensure good contact between the films 3A and 3B and the air.

[0071] (Second heat treatment step (heat setting step)) The overlapping films 3A and 3B are held at both ends by clips (not shown) of a tenter 41 and are heat-treated (heat-set) at a temperature below the melting point of the resin that makes up the film 3 and at a temperature approximately 30°C lower than the melting point, to become a biaxially stretched film 4 (hereinafter also referred to as film 4) with stable physical properties, which is then sent to the next winding process. The heat treatment temperature in this second heat treatment (heat setting) is preferably 160°C or higher, more preferably 180°C or higher. Furthermore, the heat treatment temperature in the second heat treatment (heat setting) is preferably 300°C or lower, more preferably 270°C or lower. If the heat treatment temperature is equal to or higher than the lower limit, the film shrinkage rate will not increase and the occurrence of delamination will tend to be suppressed. On the other hand, if the heat treatment temperature is equal to or lower than the upper limit, the bowing phenomenon during heat setting will not increase, distortion of the film will be suppressed, and an increase in density will be suppressed, so the crystallinity will not become too high and the film will tend to be more susceptible to deformation. In addition, the relaxation rate at this time is preferably 15% or less. A strong tension is applied to films 3A and 3B in heating furnace 42 by tension control device 50 located downstream.

[0072] (winding process) The film 4 heat-set by the second heat treatment step passes through a tension control device 50 and is taken up as films 4A and 4B on two take-up rolls 62 via a guide roll 61. These films 4A and 4B correspond to the film 1 according to this embodiment.

[0073] [Laminate] Next, a laminate including a film according to one embodiment of the present invention will be described. FIG. 3 shows a schematic cross-sectional view of a laminate according to this embodiment. The laminate 90 is a laminate having three layers: a first layer 91 , a second layer 92 , and a third layer 93 .

[0074] In the laminate 90, it is preferable that at least one of the first layer 91, the second layer 92, and the third layer 93 is a film 1 according to this embodiment, and it is more preferable that the first layer 91 or the third layer 93 is a film 1 according to this embodiment.

[0075] Of the multiple layers constituting the laminate 90, the material of the layers other than the film 1 according to this embodiment is not particularly limited and can be appropriately selected depending on the application of the laminate 90. For example, when the laminate is used as an exterior material for a lithium-ion secondary battery, as described below, the first layer 91 can be the film 1 according to this embodiment, the second layer 92 can be an aluminum film, and the third layer 93 can be a film containing polyolefin, preferably a film containing polypropylene, and more preferably a film containing crystalline polypropylene. If the third layer 93 is a film containing crystalline polypropylene, the heat resistance and chemical resistance of the entire laminate 90 can be improved. In this case, the laminate 90 may have layers other than the first layer 91 (film 1 according to this embodiment), the second layer 92 (aluminum film), and the third layer 93 (film containing polyolefin). However, it is preferable that the first layer 91 (film 1 according to this embodiment) does not have a polyethylene terephthalate film on the surface (the surface opposite to the surface in contact with the second layer 92) as the other layer.

[0076] [Packaging material] The film and laminate according to one aspect of the present invention can be used as a packaging material. Packaging materials including the film or laminate according to this embodiment can be used as packaging materials for various purposes, such as packaging for electrical components, food, pharmaceutical packaging, and daily necessities. As an example of a packaging material, an exterior material according to one embodiment of the present invention will be described below.

[0077] [Exterior materials] The packaging material according to this embodiment includes at least the film according to this embodiment. For the packaging material according to this embodiment, it is preferable to use the laminate according to this embodiment.

[0078] The exterior packaging material according to this embodiment is preferably used in secondary batteries mounted on electric vehicles, tablet terminal devices, smartphones, etc., more preferably in lithium-ion secondary batteries, and even more preferably in lithium-ion secondary batteries mounted on electric vehicles, etc. The exterior packaging material according to this embodiment can also be suitably used in all-solid-state lithium batteries.

[0079] FIG. 4 shows a schematic cross-sectional view of a lithium ion secondary battery using the exterior packaging material of this embodiment. Lithium ion secondary battery 100 includes exterior packaging materials 101A and 101B, an electrode group 105, an electrolyte 106, a positive electrode tab 107, and a negative electrode tab 108. Electrode group 105 is stacked such that a positive electrode 102 and a negative electrode 104 face each other with separator 103 sandwiched therebetween. In lithium ion secondary battery 100, exterior packaging material 101A is molded by press molding or the like, while exterior packaging material 101B is not molded.

[0080] The lithium ion secondary battery 100 is obtained, for example, by accommodating an electrode group 105 and an electrolyte solution 106 inside the exterior packaging material 101A and the exterior packaging material 101B, setting a positive electrode tab 107 at one longitudinal end of the exterior packaging material 101A and the exterior packaging material 101B and a negative electrode tab 108 at the other longitudinal end, and joining the peripheries of the exterior packaging materials 101A and 101B by thermal welding or the like.

[0081] [Effects of this embodiment] The film according to this embodiment has excellent insulating properties and chemical resistance. Furthermore, since the laminate and packaging material according to this embodiment contain such a film, they also have excellent insulating properties and chemical resistance.

[0082] Furthermore, for example, in the case of exterior materials for lithium-ion secondary batteries (LiB), especially those for automotive LiB, in order to solve the problems that arise when using nylon film on the surface of the exterior material, a typical structure has been to laminate a PET film, which has high insulating properties and excellent chemical resistance, on the surface of the nylon film (polyethylene terephthalate (PET) film / / nylon (Ny) film / / aluminum (AL) film / / crystalline polypropylene (CPP) film). However, using PET film increases the cost due to the additional material. On the other hand, the film according to this embodiment does not require protection by a PET film, and therefore the production costs can be reduced compared to conventional films.

[0083] Furthermore, since the film according to this embodiment does not require protection by a PET film, the thickness of the laminate and the exterior material can be reduced. Therefore, for example, when the exterior material according to this embodiment is used in a lithium ion secondary battery, the lithium ion secondary battery can be made thinner while maintaining insulation properties.

[0084] [Modification] The present invention is not limited to the above embodiment. For example, in the above embodiment, a laminate having a three-layer structure of a first layer, a second layer, and a third layer is exemplified, but a laminate having a two-layer structure or a multi-layer structure of four or more layers may also be used.

[0085] Furthermore, for example, in the above embodiment, an example was shown in which the exterior packaging material was used for a lithium ion secondary battery, but the exterior packaging material can also be used for various other purposes such as electrical components.

[0086] Furthermore, for example, in the above embodiment, the lithium ion secondary battery is exemplified in which only one of the exterior materials is molded, but both exterior materials of the lithium ion secondary battery may be molded. [Example]

[0087] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0088] Films were produced by the following production method. The raw material resins for the films in each example and comparative example were as follows. The blending amounts of each raw material were as shown in Table 1.

[0089] Example 1 Raw material A: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) Raw material B: MXD6 (product name: MX nylon / manufactured by Mitsubishi Gas Chemical Company, Inc. / grade name: S6007)

[0090] Example 2 Raw material A: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) Raw material B: MXD6 (product name: MX nylon / manufactured by Mitsubishi Gas Chemical Company, Inc. / grade name: S6007)

[0091] Example 3 Raw material A: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) Raw material B: Nylon 6,12 (product name: Zytel (registered trademark) / grade name: 158L_NC010 / manufactured by Toray DuPont Co., Ltd.)

[0092] Example 4 Raw material A: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) Raw material B: Nylon 6,12 (product name: Zytel (registered trademark) / grade name: 158L_NC010 / manufactured by Toray DuPont Co., Ltd.)

[0093] Example 5 Raw material A: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) Raw material B: Nylon 6,12 (product name: Zytel (registered trademark) / grade name: 158L_NC010 / manufactured by Toray DuPont Co., Ltd.)

[0094] Example 6 Raw material A: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) Raw material B: Nylon 6,12 (product name: Zytel (registered trademark) / grade name: 158L_NC010 / manufactured by Toray DuPont Co., Ltd.)

[0095] Comparative Example 1 Raw material A: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.)

[0096] <Film manufacturing> (raw film manufacturing process) As shown in Figure 2, the raw resin was melt-kneaded at 275°C in an extruder 71, and then the melt was extruded from a circular die 72 as a tubular film, followed by quenching with water (15°C) to produce a raw film 2.

[0097] (Biaxial stretching process) Next, as shown in Figure 2, this raw film 2 was inserted between a pair of pinch rolls 11, and then heated in a heating section 12 while gas was being injected into the gap, and the gas was blown onto the stretching start point to expand the film into bubbles, which were then taken up by a pair of pinch rolls 14 on the downstream side, whereby simultaneous biaxial stretching in MD and TD was performed by the tubular method. The stretching ratios were 3.0 times in MD and 3.1 times in TD.

[0098] (First heat treatment step and second heat treatment step) Next, as shown in Fig. 2, the bubble-stretched film 3 was subjected to heat treatment at a temperature of 170°C by a first heat treatment device 20. Thereafter, the film 3 was separated into films 3A and 3B via a separation device 30, and then heat treatment was performed at a temperature of 210°C by a second heat treatment device 40 to heat-set the films 3A and 3B.

[0099] (winding process) 2, the film 4 heat-set in the second heat treatment step was passed through a tension control device 50 and taken up as films 4A and 4B around two take-up rolls 62 via a guide roll 61 to produce biaxially stretched films. The thickness of the obtained biaxially stretched film was 25 μm.

[0100] <Various measurements> The obtained biaxially stretched film was subjected to the following measurements.

[0101] ·Volume specific resistivity (Ω cm) The films of Examples 1 to 6 and Comparative Example 1 were stored for one week at 23°C and 95% RH. After adjusting the film condition at 23°C and 50% RH, the film was cut into 100 mm x 100 mm pieces and the volume resistivity (Ω·cm) of the film was measured. The volume resistivity (Ω·cm) of the film was measured at a measurement voltage of 500 V using a resistivity meter (Mitsubishi Chemical Analytech, Hiresta-UX MCP-HT800) in accordance with JIS K6911. The results are shown in Table 1.

[0102] ·Water absorption rate (%) The films of Examples 1 to 6 and Comparative Example 1 were cut into 100 mm x 100 mm pieces and immersed in water at 23°C for 72 hours in accordance with JIS K7209, and immediately thereafter the water absorption was measured. The results are shown in Table 1.

[0103] Breakdown voltage (kV) The films of Examples 1 to 6 and Comparative Example 1 were stored for one week at 23°C and 95% RH. After conditioning the films at 23°C and 50% RH, they were cut into 70 mm x 70 mm pieces and their breakdown voltages (kV) were measured. The breakdown voltages (kV) of the films were measured in air at 23°C and 50% RH at a voltage rise rate of 0.3 kV / sec using a breakdown tester "YST-243-100RHO" (manufactured by Yamayo Test Instruments Co., Ltd.) in accordance with JIS C2110-1. The results are shown in Table 1.

[0104] ·Density (g / cm 3 ) Approximately 8 g±0.5 g of the films of Examples 1 to 6 and Comparative Example 1 were prepared and measured by the He gas substitution method using a dry density meter Accupyc II 1340 manufactured by Micromeritics. The density of the film of Example 2 was 1.17 g / cm 3 The density of the film of Comparative Example 1 was 1.15 g / cm 3 It was.

[0105] Thickness (μm) The thickness of the films of Examples 1 to 6 and Comparative Example 1 was measured using a thickness measuring device (ID-C112C manufactured by Mitutoyo Corporation). The results are shown in Table 1.

[0106] Tensile properties (breaking strength (MPa), elongation (%)) The films of Examples 1 to 6 and Comparative Example 1 were cut into 15 mm x 180 mm pieces, and the tensile properties of the films in MD and TD were measured. The tensile properties of the films were measured using an Instron 5965 dual column tabletop testing machine in accordance with ASTM D882. The results are shown in Table 1.

[0107] ·Piercing strength (N) The films of Examples 1 to 6 and Comparative Example 1 were each punched into a circle with a diameter of 16 mm to prepare a test sample. A needle with a diameter of 1 mm was pierced into the test sample at a piercing speed of 200 mm / min, and the strength (N) required for the needle to penetrate the test sample was measured as the piercing strength. The results are shown in Table 1.

[0108] [Table 1]

[0109] As is clear from Table 1, the films of Examples 1 to 6 were films that had tensile properties comparable to that of the film of Comparative Example 1, but were excellent in insulation properties and strength.

[0110] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also fall within the technical scope of the present invention. [Explanation of symbols]

[0111] 1...film, 2...raw film, 3...substrate film, 4...biaxially stretched film, 90...laminated body, 91...first layer, 92...second layer, 93...third layer, 100...lithium ion secondary battery, 101A, 101B...casing material, 102...positive electrode, 103...separator, 104...negative electrode, 105...electrode group, 106...electrolyte, 107...positive electrode tab, 108...negative electrode tab.

Claims

1. Contains two types of amide polymers, The two types of amide polymers include nylon 6 and nylon 6,12. the content of nylon 6 is 1% by mass or more and 40% by mass or less, the content of nylon 6,12 is 60% by mass or more and 99% by mass or less, A film having a breakdown voltage of 3.2 kV or more.

2. Volume resistivity is 1 x 10 １３ The film of claim 1 having a modulus of Ω·cm or greater.

3. 3. The film according to claim 1, wherein the film has a water absorption rate of 10% or less.

4. At least one of the two amide-based polymers has a volume resistivity of 1×10 １４ The film according to any one of claims 1 to 3, having a modulus of Ω·cm or more.

5. The film according to claim 1 , wherein at least one of the two amide-based polymers has a water absorption rate of 10% or less.

6. The film according to any one of claims 1 to 5, wherein at least one of the two amide-based polymers has a breakdown voltage of 3.1 kV or more.

7. The film according to any one of claims 1 to 6, having a thickness of 10 µm or more and 50 µm or less.

8. Density is 1.0 g / cm ３ 2.0g / cm or more ３ 8. The film of any one of claims 1 to 7, wherein:

9. 9. The film according to claim 1, wherein the tensile strength in the MD of the film is 150 MPa or more and 500 MPa or less, and the tensile strength in the TD of the film is 150 MPa or more and 500 MPa or less.

10. A laminate comprising the film of any one of claims 1 to 9.

11. A packaging material comprising the film of any one of claims 1 to 9.

12. An exterior material comprising the film of any one of claims 1 to 9.

13. An exterior material using the laminate according to claim 10.

14. The packaging material according to claim 12 or 13, which is used for a lithium ion secondary battery.

15. A method for producing the film according to claim 1 , comprising a step of stretching the film by tubular biaxial stretching.

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