Composition, base film, stretched film, laminate, packaging material, exterior material, and method for producing stretched film

Abstract

A composition comprising a polyamide resin and an ethylene-(meth)acrylate-maleic anhydride copolymer, wherein the content of (meth)acrylate structural units in the ethylene-(meth)acrylate-maleic anhydride copolymer is 9-23 mass%.

Description

Composition, raw film, stretched film, laminate, packaging material, exterior material, and method for producing stretched film

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

[0002] Films using nylon or the like are excellent in strength, impact resistance, etc. Therefore, laminated packaging materials containing such films can be suitably used for battery packaging, pharmaceutical packaging (e.g., PTP: press through pack packaging), daily necessities (e.g., refill packaging for liquid detergent), food, etc. For example, Patent Documents 1 and 2 disclose packaging materials for lithium ion batteries in which the substrate layer has a film substrate.

[0003] JP 2014-041833 A International Publication No. 2012 / 033133

[0004] Conventional films have also been usable as packaging materials for lithium-ion secondary batteries (LiBs), for example. However, in recent years, depending on the application, there has been a demand for increased capacity in packaging materials, which has made it necessary to draw the film deeply.

[0005] An object of the present invention is to provide a composition that facilitates the production of deep-drawable films, as well as raw films, stretched films, laminates, packaging materials, and exterior materials that contain the composition, and a method for producing the stretched films.

[0006] According to one aspect of the present invention, there is provided a composition comprising a polyamide resin and an ethylene-(meth)acrylate-maleic anhydride copolymer, wherein a content of (meth)acrylate structural units in the ethylene-(meth)acrylate-maleic anhydride copolymer is 9% by mass or more and 23% by mass or less.

[0007] In the composition according to one aspect of the present invention, the ethylene-(meth)acrylate-maleic anhydride copolymer may have a (meth)acrylate structural unit content of 20% by mass or less.

[0008] In the composition according to one aspect of the present invention, the ethylene-(meth)acrylate-maleic anhydride copolymer may have a melt flow rate of 9 g / 10 min or more.

[0009] In the composition according to one aspect of the present invention, the content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition may be 10% by mass or less.

[0010] In the composition according to one aspect of the present invention, the content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition may be 1% by mass or more.

[0011] In the composition according to one aspect of the present invention, the polyamide resin may be at least one resin selected from the group consisting of 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-6 ​​nylon (MXD6).

[0012] According to one aspect of the present invention, there is provided a raw film comprising a composition according to one aspect of the present invention.

[0013] According to one aspect of the present invention, there is provided a stretched film comprising a composition according to one aspect of the present invention.

[0014] In a stretched film according to one aspect of the present invention, the stretched film may have a tensile strength of 190 MPa or more at 80% elongation in MD and a tensile strength of 190 MPa or more at 80% elongation in TD.

[0015] In the stretched film according to one aspect of the present invention, the stretched film may have a pin puncture strength of 5900 N / cm or more.

[0016] According to one aspect of the present invention, there is provided a laminate including the stretched film according to one aspect of the present invention.

[0017] According to one aspect of the present invention, there is provided a packaging material comprising the stretched film according to one aspect of the present invention.

[0018] According to one aspect of the present invention, there is provided an exterior packaging material including the stretched film according to one aspect of the present invention.

[0019] According to one aspect of the present invention, there is provided an exterior packaging material including the laminate according to one aspect of the present invention.

[0020] According to one aspect of the present invention, there is provided a method for producing a stretched film according to one aspect of the present invention, comprising the steps of producing a raw film from a raw material and stretching the raw film by tubular biaxial stretching.

[0021] According to one aspect of the present invention, there is provided a method for producing a stretched film, comprising the steps of producing a raw film according to one aspect of the present invention and stretching the raw film by tubular biaxial stretching.

[0022] According to one aspect of the present invention, a composition that facilitates the production of a deep-drawable film can be provided. Also, according to another aspect of the present invention, a raw film, a stretched film, a laminate, a packaging material, and an exterior material that include the composition, as well as a method for producing a stretched film, can be provided.

[0023] Fig. 1 is a cross-sectional schematic diagram of a film according to one embodiment of the present invention. Fig. 2 is a schematic configuration diagram showing an example of an apparatus used in a method for producing a film according to one embodiment of the present invention. Fig. 3 is a cross-sectional schematic diagram of a laminate according to one embodiment of the present invention. Fig. 4 is a cross-sectional schematic diagram of a lithium ion secondary battery using an exterior material according to one embodiment of the present invention.

[0024] [First embodiment] In the first embodiment, a composition according to one aspect of the present invention will be described.

[0025] [Composition] The composition according to this embodiment contains a polyamide resin and an ethylene-(meth)acrylate-maleic anhydride copolymer.

[0026] Polyamide Resin Examples of the polyamide resin contained in the composition according to this embodiment include one or more polyamide resins selected from the group consisting of 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-6 ​​nylon (MXD6). The composition according to this embodiment may contain two or more polyamide resins.

[0027] These polyamide resins do not necessarily have to be derived from fossil fuels, and may be, for example, environmentally friendly plant-derived polyamide resins, or may be a combination of a fossil fuel-derived polyamide resin and a plant-derived polyamide resin. For example, when the composition according to the present embodiment contains two polyamide resins, both may be fossil fuel-derived polyamide resins, or one may be a fossil fuel-derived polyamide resin and the other may be a plant-derived polyamide resin, or both may be plant-derived polyamide resins.

[0028] The polyamide resin is preferably at least one resin selected from the group consisting of 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-6 ​​nylon (MXD6), and more preferably nylon 6.

[0029] The content of the polyamide resin in the composition according to the present embodiment is preferably 50% by mass or more, more preferably 75% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. The content of the polyamide resin in the composition according to the present embodiment is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less.

[0030] Ethylene-(meth)acrylate-maleic anhydride copolymer In the composition according to this embodiment, the content of (meth)acrylate structural units in the ethylene-(meth)acrylate-maleic anhydride copolymer (hereinafter sometimes referred to as "MA content") is preferably 9% by mass or more and 23% by mass or less. If the content of (meth)acrylate structural units in the ethylene-(meth)acrylate-maleic anhydride copolymer is 9% by mass or more and 23% by mass or less, the tensile strength and pin puncture strength of the stretched film containing the composition according to this embodiment at 80% elongation (when the stretched film containing the composition according to this embodiment is stretched 1.8 times) can be maintained, while reducing the stress during stretching of the raw film, and the stretching ratio can be increased. As a result, the tensile strength of the film after stretching is increased and pinholes are less likely to form during deep drawing, making it possible to produce a stretched film that can be deep drawn. Note that, for example, LiB packaging materials are molded into a convex shape by cold press molding to accommodate positive and negative electrodes, etc. Increasing the depth of this convex molding is called "deep drawing."

[0031] The content of (meth)acrylate structural units in the ethylene-(meth)acrylate-maleic anhydride copolymer is more preferably 20% by mass or less, and even more preferably 18% by mass or less. By setting the content to 20% by mass or less, the tensile strength and puncture strength at 80% elongation of the resulting stretched film tend to be higher.

[0032] The content of (meth)acrylate structural units in the ethylene-(meth)acrylate-maleic anhydride copolymer is more preferably 10% by mass or more, and even more preferably 11% by mass or more.

[0033] In the composition according to this embodiment, the melt flow rate (MFR) of the ethylene-(meth)acrylate-maleic anhydride copolymer is preferably 9 g / 10 min or more. When the MFR of the ethylene-(meth)acrylate-maleic anhydride copolymer is 9 g / 10 min or more, the dispersibility of the ethylene-(meth)acrylate-maleic anhydride copolymer in the polyamide resin is improved, and the impact strength of a stretched film made from the composition according to this embodiment is further increased.

[0034] In the composition according to the present embodiment, the MFR of the ethylene-(meth)acrylate-maleic anhydride copolymer is more preferably 10 g / 10 min or more, even more preferably 12 g / 10 min or more, and still more preferably 25 g / 10 min or more.

[0035] Furthermore, from the viewpoint of film formation stability of the raw film before stretching, in the composition according to the present embodiment, the MFR of the ethylene-(meth)acrylate-maleic anhydride copolymer is preferably 100 g / 10 min or less, more preferably 90 g / 10 min or less, and even more preferably 80 g / 10 min or less.

[0036] The melt flow rate of the ethylene-(meth)acrylate-maleic anhydride copolymer in this specification can be measured in accordance with JIS K6922-2 at a measurement temperature of 190° C. and a load of 2.16 kg.

[0037] The content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition according to this embodiment is preferably 10% by mass or less. When the content of the ethylene-(meth)acrylate-maleic anhydride copolymer is 10% by mass or less, stress during stretching of the raw film tends to be reduced while maintaining the tensile strength and pin puncture strength at 80% elongation.

[0038] The content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition according to this embodiment is more preferably 9% by mass or less, and even more preferably 8% by mass or less.

[0039] Furthermore, the content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition according to this embodiment is preferably 1% by mass or more.

[0040] The content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition according to this embodiment is more preferably 2% by mass or more, and even more preferably 3% by mass or more.

[0041] Other Components The composition according to this embodiment may contain only a polyamide resin and an ethylene-(meth)acrylate-maleic anhydride copolymer, or may contain components other than a polyamide resin and an ethylene-(meth)acrylate-maleic anhydride copolymer. For example, the composition according to this embodiment may contain one or more additives selected from the group consisting of an antiblocking agent, a slip agent, a water repellent, an anti-seizure agent, an antioxidant, and a neutralizing agent. Furthermore, the composition according to this embodiment may contain impurities to the extent that the effects of the present invention are not impaired.

[0042] [Second Embodiment] In the second embodiment, a film and a method for producing the film according to one aspect of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0043] [Film] The film according to the present embodiment includes the composition according to one aspect of the present invention. For example, the film according to one aspect of the present invention is a raw film including the composition according to one aspect of the present invention.

[0044] For example, a film according to one embodiment of the present invention is a stretched film containing a composition according to one embodiment of the present invention. The stretched film according to one embodiment of the present invention is obtained by stretching a raw film made from the composition according to one embodiment of the present invention. In this case, it is preferable that the raw film used as the raw material can be stretched under conditions where the maximum stress in the MD (machine direction) is 1.50 kgf or less and the maximum stress in the TD (transverse direction) is 1.50 kgf or less. If the maximum stresses in the MD and TD are below the above values, the stretched film can be produced while reducing the load on the equipment. The stress of the raw film can be measured according to the measurement method described in the examples below.

[0045] 1 is a schematic cross-sectional view of a stretched film 1 according to this embodiment. The stretched 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.

[0046] The stretched film 1 according to this embodiment preferably has a tensile strength of 190 MPa or more at 80% elongation in the MD (when the stretched film according to one embodiment of the present invention is stretched 1.8 times in the MD) and a tensile strength of 190 MPa or more at 80% elongation in the TD (when the stretched film according to one embodiment of the present invention is stretched 1.8 times in the TD). If the tensile strengths of the stretched film 1 at 80% elongation in both the MD and TD are 190 MPa or more, the drawing depth can be made deeper when the stretched film 1 is used to form a packaging material, and a packaging material with excellent capacity can be obtained.

[0047] The stretched film 1 according to this embodiment preferably has a tensile strength of 200 MPa or more at 80% elongation in the MD and a tensile strength of 200 MPa or more at 80% elongation in the TD, and more preferably has a tensile strength of 210 MPa or more at 80% elongation in the MD and a tensile strength of 210 MPa or more at 80% elongation in the TD.

[0048] The stretched film 1 according to this embodiment also preferably has a tensile strength of 190 MPa or more when stretched 80% in a direction at an angle of 45° to the TD (when the stretched film according to one aspect of the present invention is stretched 1.8 times in a direction at an angle of 45° to the TD), more preferably 200 MPa or more, and even more preferably 210 MPa or more.

[0049] The stretched film 1 according to this embodiment also preferably has a tensile strength of 190 MPa or more when stretched 80% in a direction at an angle of 135° to the TD (when the stretched film according to one aspect of the present invention is stretched 1.8 times in a direction at an angle of 135° to the TD), more preferably 200 MPa or more, and even more preferably 210 MPa or more.

[0050] The stretched film 1 according to this embodiment preferably has a tensile strength of 190 MPa or more at 80% elongation in a direction at an angle of 45° to the TD and a tensile strength of 190 MPa or more at 80% elongation in a direction at an angle of 135° to the TD. If the tensile strengths at 80% elongation in the direction at an angle of 45° to the TD and the tensile strengths at 80% elongation in the direction at an angle of 135° to the TD are both 190 MPa or more, no anisotropy in elongation occurs when the stretched film is press-molded, and breakage can be prevented.

[0051] In this case, more preferably, the tensile strength at 80% elongation in a direction at an angle of 45° to TD is 200 MPa or more, and the tensile strength at 80% elongation in a direction at an angle of 135° to TD is 200 MPa or more, and even more preferably, the tensile strength at 80% elongation in a direction at an angle of 45° to TD is 210 MPa or more, and the tensile strength at 80% elongation in a direction at an angle of 135° to TD is 210 MPa or more.

[0052] In the stretched film 1 according to this embodiment, the difference between the average values ​​of the tensile strength at 80% elongation in the MD, the tensile strength at 80% elongation in the TD, the tensile strength at 80% elongation in a direction at an angle of 45° to the TD, and the tensile strength at 80% elongation in a direction at an angle of 135° to the TD and each tensile strength is preferably 70 MPa or less. It is also preferable that the stretched film 1 according to this embodiment has a difference between the maximum and minimum values ​​of the tensile strength at 80% elongation in the MD, the tensile strength at 80% elongation in the TD, the tensile strength at 80% elongation in a direction at an angle of 45° to the TD, and the tensile strength at 80% elongation in a direction at an angle of 135° to the TD being 60 MPa or less. When the difference between the maximum and minimum values ​​in the stretched film 1 is 60 MPa or less, there is no variation in tensile strength between the directions, and the stretched film 1 can be used to form a packaging material into a desired shape.

[0053] The stretched film 1 according to this embodiment preferably has a MD tensile strength of 290 MPa or more, more preferably 300 MPa or more. The stretched film 1 according to this embodiment also has a MD tensile strength of 450 MPa or less, more preferably 420 MPa or less. The stretched film 1 according to this embodiment also has a TD tensile strength of 290 MPa or more, more preferably 300 MPa or more. The stretched film 1 according to this embodiment also has a TD tensile strength of 450 MPa or less, more preferably 420 MPa or less.

[0054] When the tensile properties (breaking strength) in at least one of the MD and TD of the stretched film 1 according to the present embodiment are within the above range, the stretched film 1 has excellent formability. If the stretched film 1 has excellent formability, laminates and packaging materials including the stretched film 1 can be easily press-molded.

[0055] The stretched film 1 according to this embodiment preferably has a tensile strength in the MD of 290 MPa or more and a tensile strength in the TD of 290 MPa or more, more preferably both of 300 MPa or more, and even more preferably both of 310 MPa or less.

[0056] Furthermore, the stretched film 1 according to this embodiment preferably has an MD tensile property of elongation at break (hereinafter sometimes referred to as "elongation") of 50% or more, more preferably 55% or more, and even more preferably 60% or more. The stretched film 1 according to this embodiment preferably has an MD tensile property of 100% or less, more preferably 95% or less, and even more preferably 90% or less. The stretched film 1 according to this embodiment preferably has a TD tensile property of 50% or more, more preferably 55% or more, and even more preferably 60% or more. The stretched film 1 according to this embodiment preferably has a TD tensile property of 100% or less, more preferably 95% or less, and even more preferably 90% or less.

[0057] When the tensile properties (elongation percentage) in at least one of the MD and TD of the stretched film 1 according to this embodiment are within the above range, the stretched film 1 has better formability.

[0058] The stretched film 1 according to the present embodiment preferably has MD tensile properties of 50% or more and TD tensile properties of 50% or more, and more preferably both of 55% or less.

[0059] The tensile properties (tensile strength, modulus of elasticity, breaking strength, and breaking elongation) of the stretched film 1 can be measured in accordance with ASTM D882. Specifically, they can be measured in accordance with the measurement methods described in the examples below.

[0060] From the viewpoint of improving pinhole resistance, the stretched film 1 according to this embodiment preferably has a puncture strength of 5900 N / cm or more. The stretched film 1 according to this embodiment more preferably has a puncture strength of 6100 N / cm or more, and even more preferably has a puncture strength of 6300 N / cm or more. Furthermore, the stretched film 1 according to this embodiment preferably has a puncture strength of 20000 N / cm or less, more preferably has a puncture strength of 18000 N / cm or less, and even more preferably has a puncture strength of 16000 N / cm or less. Note that the puncture strength in this specification can be measured in accordance with the measurement method described in the Examples below.

[0061] From the viewpoint of improving impact resistance, the stretched film 1 according to this embodiment preferably has an impact strength of 80,000 J / m or more. The stretched film 1 according to this embodiment more preferably has an impact strength of 85,000 J / m or more, and even more preferably has an impact strength of 90,000 J / m or more. Furthermore, the stretched film 1 according to this embodiment preferably has an impact strength of 300,000 J / m or less, more preferably has an impact strength of 280,000 J / m or less, and even more preferably has an impact strength of 200,000 J / m or less. Note that the impact strength in this specification can be measured in accordance with the measurement method described in the Examples below.

[0062] From the viewpoint of improving pinhole resistance, the film 1 according to this embodiment preferably has a pinhole count of 15 or less per A4 sheet when measured at 23°C and 1000 times using a Gelbo flex tester. The pinhole count is more preferably 10 or less per A4 sheet, and even more preferably 5 or less per A4 sheet. The pinhole count in this specification is a value measured after the stretched film 1 according to this embodiment is produced.

[0063] The method for producing a stretched film according to the present embodiment is not particularly limited. As an example, a method for producing a stretched film including a step of stretching by tubular biaxial stretching will be described below with reference to the drawings.

[0064] [Apparatus for Producing Stretched Film] First, an example of an apparatus for producing the stretched film of this embodiment will be described.

[0065] 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 films, an upper film and a lower film, 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.

[0066] As shown in Fig. 2, the raw film manufacturing apparatus 70 includes an extruder 71, a circular die 72, a water-cooling ring 73, a stabilizer plate 74, and a pinch roll 75. The tubular stretching apparatus 10 is an apparatus for biaxially stretching (bubble stretching) a tubular raw film 2 using internal air pressure to manufacture a film 3. As shown in Fig. 2, the tubular stretching apparatus 10 includes a pinch roll 11, a heating section 12, a guide plate 13, and a pinch roll 14.

[0067] The first heat treatment device 20 is a device for preliminarily heat treating the flattened film 3. As shown in FIG. 2 , the first heat treatment device 20 includes a tenter 21 and a heating furnace 22.

[0068] 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.

[0069] 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.

[0070] [Method for Producing Biaxially Stretched Film] Next, each step for producing a biaxially stretched film using this film production apparatus 80 will be described in detail.

[0071] (Process for Producing Raw Film) As shown in FIG. 2, a composition containing a polyamide resin and an ethylene-(meth)acrylate-maleic anhydride copolymer as raw materials is melt-kneaded by 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 molten resin by the water-cooling ring 73. This raw film 2 corresponds to the raw film according to this embodiment. 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.

[0072] (Biaxial Stretching Process) As shown in Figure 2, the 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 plates 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.

[0073] In this case, by setting the MD and TD stretching ratios to 2.8 or more, respectively, improved impact strength can be expected. Furthermore, by containing an ethylene-(meth)acrylate-maleic anhydride copolymer in the raw film, the load on the equipment in the biaxial stretching process can be reduced, and the stretching ratio can be increased. The MD and TD stretching ratios are preferably 3.0 or more, more preferably 3.3 or more, and even more preferably 3.5 or more. Furthermore, the difference (TD-MD) obtained by subtracting the MD stretching ratio from the TD stretching ratio is preferably 0.4 or less, more preferably 0.3 or less, and even more preferably 0.2 or less. Furthermore, the value of TD-MD is more preferably 0.1 or more. When the value of TD-MD is below the upper limit, the deep drawability of the resulting film tends to be sufficient. Furthermore, when the value of TD-MD is 0.2 or less, the deep drawability of the film is particularly excellent. On the other hand, 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.

[0074] (First Heat Treatment Step) The film 3 sent from the biaxial stretching step 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 step. 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 slipperiness between overlapping films.

[0075] (Separation Process) As shown in FIG. 2, the flat film 3 fed through the guide rolls 31 is separated into two films 3A and 3B by a blade 321 of a trimming device 32, which cuts both ends of the film 3A and 3B. The films 3A and 3B are then separated by a pair of separation rolls 33A and 33B, spaced apart vertically, with air interposed between them. The cutting of the flat film 3 may be performed by positioning the blade 321 slightly inward from both ends to create partial selvages, or by positioning the blade 321 at the fold of the film 3 to prevent the creation of selvages. The films 3A and 3B are then stacked again by three grooved rolls 34A, 34B, and 34C positioned sequentially in the film flow direction and sent to the next second heat treatment process. Note that these grooved rolls 34A, 34B, and 34C have plated surfaces after being grooved. These grooves ensure good contact between the films 3A and 3B and the air.

[0076] (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 polyamide resin constituting the film 3 and at least about 30°C lower than the melting point, to form a biaxially stretched film 4 (hereinafter also referred to as film 4) with stable physical properties. This film 4 corresponds to the stretched film 1 according to this embodiment. The heat treatment temperature in this second heat treatment (heat setting) is preferably 160°C or higher, more preferably 180°C or higher. 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 above the lower limit, the film shrinkage rate does not become too large and the occurrence of delamination tends to be suppressed. On the other hand, if the relaxation rate is below the upper limit, the bowing phenomenon during heat setting does not become significant, distortion of the film can be suppressed, and an increase in density can be suppressed, so the crystallinity does not become too high and the film tends to be easily deformed. Furthermore, the relaxation rate at this time is preferably 15% or less. A strong tension is applied to the films 3A and 3B in the heating furnace 42 by the tension control device 50 located downstream. The film 4 is sent to the next winding process as needed.

[0077] (Winding Step) The film 4 heat-set in the second heat treatment step passes through the tension control device 50 and is wound around two winding rolls 62 via guide rolls 61 as films 4A and 4B.

[0078] Third Embodiment In a third embodiment, a laminate, a packaging material, and an exterior material according to one aspect of the present invention will be described.

[0079] [Laminate] The laminate according to this embodiment includes a stretched film according to one aspect of the present invention. Fig. 3 shows a schematic cross-sectional view of the 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.

[0080] 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 stretched film 1 according to one embodiment of the present invention, and it is more preferable that the first layer 91 or the third layer 93 is a stretched film 1 according to one embodiment of the present invention.

[0081] Among the multiple layers constituting the laminate 90, the material of the layer other than the stretched film 1 according to one embodiment of the present invention is not particularly limited. It can be appropriately selected depending on the application of the laminate 90. For example, as described below, when the laminate is used as an exterior material for a lithium-ion secondary battery, the first layer 91 can be the stretched film 1 according to one embodiment of the present invention, 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. In this case, the laminate 90 may have layers other than the first layer 91 (stretched film 1 according to one embodiment of the present invention), the second layer 92 (aluminum film), and the third layer 93 (film containing polyolefin).

[0082] [Packaging Material] The packaging material according to this embodiment includes a stretched film according to one aspect of the present invention. The packaging material according to this embodiment can be used as a packaging material for various purposes, such as for electrical components, food, pharmaceutical packaging, and daily necessities. As an example of the packaging material, an exterior packaging material according to one aspect of the present invention will be described below.

[0083] [Sheathing Material] The sheathing material according to this embodiment includes the stretched film according to one aspect of the present invention.

[0084] The exterior packaging material according to the present embodiment is preferably used for pharmaceutical packaging such as press-through packaging, or for secondary batteries installed in electric vehicles, tablet terminal devices, smartphones, and the like. When the exterior packaging material according to the present embodiment is used for secondary batteries, it is more preferably used for lithium-ion secondary batteries, and even more preferably for lithium-ion secondary batteries for automotive applications such as electric vehicles. The exterior packaging material according to the present embodiment can also be suitably used for all-solid-state lithium batteries. The stretched film according to one aspect of the present invention is capable of deep drawing. Therefore, when the stretched film according to one aspect of the present invention is used as an exterior packaging material, the internal volume of the exterior packaging material can be increased. For example, when the exterior packaging material according to the present embodiment is used as an LiB exterior packaging material, the battery capacity can be increased (more battery materials can be added). Furthermore, for example, when the exterior packaging material according to the present embodiment is used as a press-through packaging material, it is possible to add larger tablets.

[0085] The packaging material according to the present embodiment also preferably includes the laminate according to one aspect of the present invention.

[0086] 4 shows a cross-sectional schematic diagram of a lithium-ion secondary battery using the exterior material of this embodiment. The lithium-ion secondary battery 100 includes exterior materials 101A and 101B, an electrode group 105, an electrolyte 106, a positive electrode tab 107, and a negative electrode tab 108. The electrode group 105 is stacked such that the positive electrode 102 and the negative electrode 104 face each other with a separator 103 sandwiched therebetween. In the lithium-ion secondary battery 100, the exterior material 101A is drawn by press molding or the like (a storage portion capable of storing the electrode group 105 and the like is formed), while the exterior material 101B is not molded.

[0087] 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 end in the longitudinal direction of the exterior packaging material 101A and the exterior packaging material 101B, and setting a negative electrode tab 108 at the other end, and joining the peripheries of the exterior packaging materials 101A and 101B by heat welding or the like.

[0088] [Modifications] The present invention is not limited to the above embodiment. For example, in the second embodiment, the manufacturing method including the first heat treatment step and the second heat treatment step (heat setting step) as the heat treatment step is exemplified, but it is also possible to perform only the second heat treatment step (heat setting step) without performing the first heat treatment step.

[0089] For example, in the third 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.

[0090] Furthermore, for example, in the third embodiment, an example has been shown in which the exterior material is used for a lithium ion secondary battery, but the exterior material can also be used for various other purposes such as electrical components.

[0091] Furthermore, for example, in the third embodiment, the lithium ion secondary battery is exemplified in which only one of the exterior materials is draw-formed, but both exterior materials in the lithium ion secondary battery may be draw-formed.

[0092] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0093] [Evaluation 1] Films were produced and evaluated by the production method described below. The raw materials 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.

[0094] Examples 1 to 4 <Polyamide Resins> A1: Nylon 6 (trade name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) <Ethylene-(meth)acrylate-maleic anhydride copolymer> B1: Ethylene-methyl acrylate-maleic anhydride copolymer (trade name: Rexpearl ET530H / manufactured by Japan Polyethylene Co., Ltd.)

[0095] Examples 5 to 8 <Polyamide Resins> A1: Nylon 6 (trade name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) <Ethylene-(meth)acrylate-maleic anhydride copolymer> B2: Ethylene-methyl acrylate-maleic anhydride copolymer (trade name: Rexpearl ET330H / manufactured by Japan Polyethylene Co., Ltd.)

[0096] Examples 9 and 10 <Polyamide Resin> A1: Nylon 6 (trade name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) <Ethylene-(meth)acrylate-maleic anhydride copolymer> B3: Ethylene-methyl acrylate-maleic anhydride copolymer (trade name: Rexpearl ET350X / manufactured by Japan Polyethylene Co., Ltd.)

[0097] Comparative Example 1 <Polyamide Resin> A1: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.)

[0098] Comparative Examples 2 and 3 <Polyamide Resin> A1: Nylon 6 (trade name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) <Ethylene-(meth)acrylate-maleic anhydride copolymer> B4: Ethylene-methyl acrylate-maleic anhydride copolymer (trade name: Rexpearl ET220X / manufactured by Japan Polyethylene Co., Ltd.)

[0099] <Film Production> (Process for Producing Raw Film) Using the above-mentioned polyamide resin and ethylene-(meth)acrylate-maleic anhydride copolymer (only polyamide resin was used in Comparative Example 1), a sheet having a thickness of 80 μm was produced using a T-die extrusion molding machine (manufactured by Labtech). The sheet was cut into a square having an MD of 85 mm and a TD of 85 mm to produce a raw film before stretching.

[0100] (Biaxial stretching process) Next, using a biaxial stretching machine (model number BIX-702S) manufactured by Iwamoto Seisakusho, the unstretched raw film was stretched at a stretching temperature of 130 ° C., a preheating time of 30 seconds, and a stretching speed of 60 mm / sec to produce a stretched film. In Examples 1, 5, and 9, and Comparative Examples 1 and 2, the stretching ratios in MD and TD were each 3.3 times, and in Table 1, the "stretching ratio (MD x TD)" was expressed as 3.3 x 3.3. In Examples 2 to 4, 6 to 8, and 10, and Comparative Example 3, the stretching ratios in MD and TD were each 3.5 times, and in Table 1, the "stretching ratio (MD x TD)" was expressed as 3.5 x 3.5.

[0101] (Heat Treatment Step) The stretched film was then fixed to a 150 mm x 150 mm SUS plate with clips so that the relaxation rate was 5%, and the stretched film was subjected to heat treatment (heat setting) in a thermostatic chamber at 210°C for 4 minutes.

[0102] <Various Measurements> The stretched film after heat setting was evaluated for various physical properties (thickness, tensile properties, puncture strength, and impact strength) as follows. In addition, as described later, a separate sample was prepared, and the stretching stress and stretching stress ratio of the raw film were measured.

[0103] Thickness (μm) The thickness of each film of Examples 1 to 10 and Comparative Examples 1 to 3 was measured using a thickness measuring device (ID-C112C manufactured by Mitutoyo Corporation). The results are shown in Table 1.

[0104] Tensile Properties (Modulus of Elasticity (MPa) and Tensile Strength (MPa)) The films of Examples 1 to 10 and Comparative Examples 1 to 3 were each cut into a size of 15 mm wide x 180 mm long, and the tensile properties were measured in the MD, TD, a direction at 45° to the TD, and a direction at 135° to the TD of the film. The tensile properties of the film were measured in accordance with ASTM D882 using an Instron 5965 dual column tabletop testing machine, including the modulus of elasticity and the tensile strength when the film was elongated by 80%. The results are shown in Table 1.

[0105] Puncture strength (N / cm) Test samples were prepared by punching out a circle having a diameter of 16 mm from each of the films of Examples 1 to 10 and Comparative Examples 1 to 3. A needle having a diameter of 1 mm was pierced into each 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 pierce strength (N / cm). The results are shown in Table 1.

[0106] Impact Strength (J / m) Each of the films of Examples 1 to 10 and Comparative Examples 1 to 3 was cut into a size of 10 cm x 10 cm to prepare a square test sample. Using a film impact tester (model number 181) manufactured by Yasuda Seiki Seisakusho Co., Ltd., a hemispherical pendulum (diameter 1.0 inch) was struck against the fixed square test sample to measure the impact strength (J / m) required to punch out the test sample. The results are shown in Table 1.

[0107] Stretching stress ratio Using the above-mentioned polyamide resin and ethylene-(meth)acrylate-maleic anhydride copolymer (only polyamide resin in Comparative Example 1), a 40 μm thick sheet was produced using a T-die extrusion molding machine (manufactured by Labtech). The sheet was cut into a square with an MD of 85 mm and a TD of 85 mm to produce a pre-stretched raw film. Using a biaxial stretching birefringence apparatus (model RS-2KI) manufactured by Eversokki, the pre-stretched raw film was stretched at a stretching temperature of 110°C, a preheating time of 60 seconds, and a stretching speed of 30 mm / sec, and the stress was measured. The stretching ratio was MD×TD=3.3×3.3 in Examples 1, 5, and 9, and Comparative Examples 1 and 2, and MD×TD=3.5×3.5 in Examples 2 to 4, 6 to 8, and 10, and Comparative Example 3, and the maximum stress in MD and TD was measured. The stretching stress ratio was calculated based on the measurement results and the following formula. The results are shown in Table 1. Stretching stress ratio = "Maximum stress of each sample" / "Maximum stress of Comparative Example 1"

[0108]

[0109] As shown in Table 1, the raw films of Examples 1 to 10, which contain a composition according to one embodiment of the present invention, have a lower maximum stress in at least one of the MD and TD than the raw film of Comparative Example 1. Therefore, the stretching ratio can be increased when producing a stretched film from the raw film according to one embodiment of the present invention. As a result, the tensile strength of the resulting stretched film can be improved, allowing for the production of a deep-drawable stretched film. Furthermore, the stretched films of Examples 1 to 10, which contain a composition according to one embodiment of the present invention, have sufficient tensile strength, puncture strength, and breaking strength. Therefore, the stretched film according to one embodiment of the present invention allows for the production of deep-drawable packaging materials that are less likely to develop pinholes during drawing molding of LiB packaging materials, etc.

[0110] [Evaluation 2] Films were produced and evaluated by the following production method. The raw materials for the films in each example and comparative example were as follows. The blending amounts of each raw material were as shown in Table 2.

[0111] Examples 11 and 12 <Polyamide Resin> A1: Nylon 6 (trade name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.) <Ethylene-(meth)acrylate-maleic anhydride copolymer> B1: Ethylene-methyl acrylate-maleic anhydride copolymer (trade name: Rexpearl ET530H / manufactured by Japan Polyethylene Co., Ltd.)

[0112] Comparative Example 4 <Polyamide Resin> A1: Nylon 6 (product name: UBE NYLON / grade name: 1022 / manufactured by Ube Industries, Ltd.)

[0113] <Film Production> Films of Examples 11 and 12 and Comparative Example 4 were produced using the film production apparatus 80 shown in FIG.

[0114] (Process for Producing Raw Film) The above-mentioned polyamide resin and ethylene-(meth)acrylate-maleic anhydride copolymer (only polyamide resin was used in Comparative Example 4) were melt-kneaded using an extruder 71, and then extruded into a tubular shape using a circular die 72. The tubular molten resin was cooled (quenched) using a water-cooling ring 73, thereby forming a raw film 2.

[0115] (Biaxial Stretching Process) As shown in FIG. 2, the raw film 2 produced in the raw film manufacturing process was introduced into the device as a flat film by a pinch roll 11, and then heated by infrared rays in a heating section 12, thereby bubble stretching the raw film 2. The stretching speed in the biaxial stretching process was 120 m / min. In addition, in Examples 11 and 12, the MD stretching ratio was 3.4 times and the TD stretching ratio was 3.5 times, respectively, and in Table 2, the "stretching ratio (MD x TD)" was expressed as 3.4 x 3.5. In Comparative Example 4, the MD stretching ratio was 3.0 times and the TD stretching ratio was 3.3 times, and in Table 2, the "stretching ratio (MD x TD)" was expressed as 3.0 x 3.3.

[0116] (First Heat Treatment Step) The first heat treatment was carried out while both ends of the film 3 sent from the biaxial stretching step were held with clips (not shown) of the tenter 21. The heat treatment temperature in this first heat treatment was 150°C.

[0117] (Separation Step) After the first heat treatment step, the flat film 3 fed via guide rolls 31 was separated into two films 3A and 3B by cutting both ends with blade 321 of trimming device 32, as shown in Fig. 2. Then, a pair of separation rolls 33A and 33B positioned above and below separated the films 3A and 3B, while interposing air between the films 3A and 3B. These films 3A and 3B were again superimposed by three grooved rolls 34A, 34B, and 34C positioned in order in the film flow direction.

[0118] (Second Heat Treatment Step (Heat Fixing Step)) The second heat treatment (heat fixing) was performed while both end portions of the overlapped films 3A and 3B were held with clips (not shown) of the tenter 41. The heat treatment temperature in this second heat treatment was 213°C.

[0119] <Various Measurements> Various physical properties (thickness, tensile properties (elastic modulus, tensile strength, breaking strength, and elongation), pin puncture strength, and impact strength) of the stretched films after heat setting were evaluated. The thickness, tensile properties (elastic modulus and tensile strength), pin puncture strength, and impact strength were measured in the same manner as in [Evaluation 1], and the tensile properties (breaking strength and elongation) and flex pinhole resistance were evaluated as follows. The deep drawability (forming depth) of the obtained stretched films was also evaluated. The evaluation results are shown in Table 2.

[0120] Tensile Properties (Breaking Strength (MPa) and Elongation (%)) The films of Examples 11 and 12 and Comparative Example 4 were cut into 15 mm x 180 mm pieces, and the breaking strength (MPa) and elongation (%) of the films in the MD and TD were measured. The breaking strength of the films was measured in accordance with ASTM D882 using an Instron 5965 dual column benchtop testing machine.

[0121] - Pinhole Resistance to Bending The films of Examples 11 and 12 and Comparative Example 4 were cut to a size of 21.0 cm (14.3 inches) x 29.7 cm (11.7 inches) to prepare rectangular test films. These test films were then wound up into a cylindrical shape with a length of 21.0 cm (14.3 inches). One end of the cylindrical film was then fixed to the outer periphery of the disk-shaped fixed head of a Gelbo Flex Tester (manufactured by Rigaku Kogyo Co., Ltd.), and the other end of the cylindrical film was fixed to the outer periphery of the disk-shaped movable head of a tester facing the fixed head with a gap of 17.8 cm (7.0 inches). The movable head was then rotated 440° while approaching the fixed head along the axes of the two parallel, opposing heads by 8.8 cm (3.5 inches), and then moved straight forward 6.4 cm (2.5 inches) without rotating, and then these movements were reversed to return the movable head to its original position. This cycle of bending tests was continuously repeated at a rate of 40 cycles per minute. After preparing the test film, the bending tests were conducted at 23°C for a total of 1,000 cycles and at -20°C for a total of 1,000 cycles. The number of pinholes (A4 size: 528.7 cm) that appeared in the 17.8 cm (7.0 inches) x 29.7 cm (11.7 inches) area of ​​the tested film, excluding the area fixed to the fixed head and the outer periphery of the movable head, was counted. ２ The number of pinholes per 81.9 square inches was measured.

[0122] Molding Depth AL (Toyo Aluminum K.K., product name: TY-X2, thickness 40 μm) and CPP (Idemitsu Unitech Co., Ltd., Unilux RT-610C, thickness 80 μm) were laminated in this order on one side of the obtained films of Examples 11 to 12 and Comparative Example 4, and the films were then dry laminated. The adhesives used were Toyo-Morton Co., Ltd., base resin TM-K55 and curing agent CAT-10L. The female mold was 120 mm x 100 mm, the male mold was 118 mm x 98 mm, the mold closing pressure was 0.3 MPa, and the stroke speed was 50 mm / sec. Drawing molding was performed, and the molding depth was evaluated. The drawing depth was changed from 5.00 to 9.00 mm in 0.5 mm increments, and five moldings were performed. The depth at which molding was successful all five times was recorded as the molding depth.

[0123]

[0124] As shown in Table 2, the stretched films of Examples 11 and 12, which contain a composition according to one embodiment of the present invention, can be produced from a raw film according to one embodiment of the present invention at a higher stretch ratio. As a result, the tensile strength of the resulting stretched film can be improved. Therefore, as shown in Table 2, the stretched films of Examples 11 and 12 were capable of deeper drawing than the stretched film of Comparative Example 4.

[0125] 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.

[0126] REFERENCE SIGNS LIST 1...stretched 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. A composition comprising a polyamide resin and an ethylene-(meth)acrylate-maleic anhydride copolymer, wherein the content of the (meth)acrylate structural unit in the ethylene-(meth)acrylate-maleic anhydride copolymer is 9% by mass or more and 23% by mass or less.

2. The composition according to claim 1, wherein the content of the (meth)acrylate structural unit in the ethylene-(meth)acrylate-maleic anhydride copolymer is 20% by mass or less.

3. The composition according to claim 1 or 2, wherein the melt flow rate of the ethylene-(meth)acrylate-maleic anhydride copolymer is 9 g / 10 min or more.

4. The composition according to any one of claims 1 to 3, wherein the content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition is 10% by mass or less.

5. The composition according to any one of claims 1 to 4, wherein the content of the ethylene-(meth)acrylate-maleic anhydride copolymer in the composition is 1% by mass or more.

6. The polyamide resin is at least one resin selected from the group consisting of 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-6 nylon (MXD6). The composition according to any one of claims 1 to 5.

7. A raw film comprising the composition according to any one of claims 1 to 6.

8. A stretched film comprising the composition according to any one of claims 1 to 6.

9. The stretched film according to claim 8, wherein the tensile strength at 80% elongation in the MD is 190 MPa or more, and the tensile strength at 80% elongation in the TD is 190 MPa or more.

10. The stretched film according to claim 8 or 9, wherein the puncture strength of the stretched film is 5900 N / cm or more.

11. A laminate comprising the stretched film according to any one of claims 8 to 10.

12. A packaging material comprising the stretched film according to any one of claims 8 to 10.

13. An exterior material comprising the stretched film according to any one of claims 8 to 10.

14. An exterior material comprising the laminate according to claim 11.

15. A method for manufacturing a stretched film according to any one of claims 8 to 10, the method comprising a step of manufacturing a mother roll film from a raw material and a step of stretching by tubular biaxial stretching.

16. A method for manufacturing a stretched film, the method comprising a step of manufacturing the mother roll film according to claim 7 and a step of stretching the mother roll film by tubular biaxial stretching.

Images