Multilayer

Abstract

To provide a multilayer body which has high pinhole resistance, and high oxygen barrier property.SOLUTION: A multilayer body has a stretched film containing more than 60 mass% of a polyamide resin (A), and other layers other than the stretched film, wherein the polyamide resin (A) contains a constitutional unit derived from diamine and a constitutional unit derived from a dicarboxylic acid, 70 mol% or more of the constitutional unit derived from the diamine is derived from xylylenediamine, 70.1-92.0 mol% of the constitutional unit derived from the dicarboxylic acid is derived from an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 8 carbon atoms, and 29.9-8.0 mol% of an α,ω-straight-chain aliphatic dicarboxylic acid having 9 to 12 carbon atoms.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multilayer body. [Background technology]

[0002] Polyamide resins are widely used as various industrial materials due to their excellent processability, mechanical strength, durability, heat resistance, oxygen barrier properties, chemical resistance, and the like. Aliphatic polyamide resins, such as polyamide 6 and polyamide 66, have long been used as such polyamide resins. Furthermore, aromatic polyamide resins, which use aromatic dicarboxylic acids and / or aromatic diamines as raw materials for the polyamide resin, have also come into use. Known examples of such aromatic polyamide resins include polyamide resin (MXD6) synthesized from metaxylylenediamine and adipic acid. For example, Patent Document 1 discloses a film laminate in which a polyamide layer (A) containing a xylylene-based polyamide resin (a) as a main component and a layer (B) made of a polyamide resin composition are laminated together, and the polyamide resin composition contains 74 to 94 mass% of a polyamide resin (b), 0.1 to 2.8 mass% of an olefin-based elastomer, 0.01 to 3 mass% of an ionomer resin, and 5.5 to 20 mass% of a polyamide resin (c), wherein the polyamide resin (b) is an aliphatic polyamide resin and the polyamide resin (c) is a xylylene-based polyamide resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 073560 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, when a multilayer structure is formed by combining a polyamide resin layer (MXD6 layer) synthesized from metaxylylenediamine and adipic acid with a polyamide 6 layer or a polyolefin layer, the polyamide 6 layer and the polyolefin layer have excellent flexibility, while the MXD6 layer is rigid, so pinholes tend to form in the MXD6 layer. In particular, when the MXD6 layer functions as a barrier layer in a multilayer structure, pinholes formed in the MXD6 layer can cause a decrease in barrier properties. Furthermore, pinholes originating from the MXD6 layer can also form in the multilayer structure. The present invention aims to solve the above problems and to provide a multilayer body having high pinhole resistance and high oxygen barrier properties. [Means for solving the problem]

[0005] In light of the above-mentioned problems, the present inventors have conducted research and found that the problems can be solved by using an α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms in combination with an α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms, such as adipic acid, as a raw material monomer for the polyamide resin used in the polyamide resin layer. Specifically, the above problems were solved by the following means. <1> A multilayer body having a stretched film containing more than 60% by mass of polyamide resin (A) and a layer other than the stretched film, wherein the polyamide resin (A) contains diamine-derived structural units and dicarboxylic acid-derived structural units, 70 mol % or more of the diamine-derived structural units being derived from xylylenediamine, and 70.1 to 92.0 mol % of the dicarboxylic acid-derived structural units being derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms and 29.9 to 8.0 mol % being derived from an α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms. <2> At least one of the other layers is a layer containing polyamide 6 and / or polyamide 6 / 66, <1> The multilayer body according to claim 1. <3> At least one of the other layers is a layer containing polyolefin. <1> or <2> The multilayer body according to claim 1. <4> 75.0 to 88.0 mol % of the dicarboxylic acid-derived structural units are derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 8 carbon atoms, and 25.0 to 12.0 mol % are derived from α,ω-linear aliphatic dicarboxylic acids having 9 to 12 carbon atoms. <1> ~ <3> 10. The multilayer body according to any one of the preceding items. <5> The α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms includes adipic acid, and the α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms includes sebacic acid. <1> ~ <4> 10. The multilayer body according to any one of the preceding items. <6> 70 mol % or more of the diamine-derived structural units are derived from metaxylylenediamine, <1> ~ <5> 10. The multilayer body according to any one of the preceding items. [Effects of the Invention]

[0006] The present invention makes it possible to provide a multilayer body having high pinhole resistance and high oxygen barrier properties. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of the multilayer body of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a method for measuring the gel fraction in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit. In this specification, various physical properties and characteristic values ​​are those at 23°C unless otherwise specified. In this specification, ppm means ppm by mass. If the standards shown in this specification differ depending on the year and the measurement method, etc., they will be based on the standards as of January 1, 2021, unless otherwise stated.

[0009] The multilayer body of this embodiment includes a stretched film (sometimes referred to herein as a "polyamide resin layer") containing more than 60% by mass of polyamide resin (A), and a layer other than the stretched film. The polyamide resin (A) contains diamine-derived structural units and dicarboxylic acid-derived structural units, with at least 70 mol % of the diamine-derived structural units being derived from xylylenediamine. Of the dicarboxylic acid-derived structural units, 70.1 to 92.0 mol % are derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 8 carbon atoms and 29.9 to 8.0 mol % are derived from α,ω-linear aliphatic dicarboxylic acids having 9 to 12 carbon atoms. This configuration allows for the production of a multilayer body with high pinhole resistance and high oxygen barrier properties. Furthermore, the molding temperature can be lowered, resulting in a multilayer body in which gelation of the polyamide resin layer is suppressed.

[0010] That is, a polyamide resin layer containing more than 60% by mass of a polyamide resin synthesized from xylylenediamine and an α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms, such as adipic acid, has excellent oxygen barrier properties and functions as an oxygen barrier layer in a multilayer structure. However, because such a polyamide resin layer is rigid, it is thought that pinholes are likely to form in the polyamide resin layer when it is combined with a flexible layer, such as a polyamide 6 layer or a polyolefin layer, in a multilayer structure. In this embodiment, it is thought that by modifying the polyamide resin used in the polyamide resin layer with an α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms, high pinhole resistance can be achieved while maintaining the excellent oxygen barrier properties of the polyamide resin layer.

[0011] Fig. 1 shows an example of a cross-sectional view of a multilayer body of this embodiment, with 1 indicating the multilayer body, 2 indicating a polyamide resin layer (stretched film), and 3 indicating other layers. As shown in Fig. 1, the multilayer body 1 of this embodiment has another layer 3 other than the stretched film 2. The other layer is, for example, a highly flexible layer, and examples thereof include a layer containing an aliphatic polyamide resin (preferably a layer containing polyamide 6 and / or polyamide 66 / 6, more preferably a layer containing polyamide 6), a layer containing a polyolefin, an adhesive layer, a sealant layer, an oxygen absorbing layer, an oxygen permeable layer, a metal vapor deposition layer, a design layer (paper, resin), an aroma retaining layer, an oil-resistant layer, a water vapor barrier layer, a flame-retardant layer, an insulating layer, an easy-cut layer, and an anti-fogging layer. The multilayer body of this embodiment may have only one other layer, or may have two or more other layers. The number of other layers is preferably one or more, more preferably two or more, or may be three or more, and is preferably ten or less, more preferably eight or less, or may be five or less. Two or more layers having the same performance may also be used.

[0012] A first example of the multilayer body of this embodiment is a multilayer body in which at least one of the other layers is a layer containing an aliphatic polyamide resin (preferably a layer containing polyamide 6 and / or polyamide 66 / 6, more preferably a layer containing polyamide 6) (hereinafter, sometimes referred to as an "aliphatic polyamide resin layer"). In this embodiment, the aliphatic polyamide resin layer and the polyamide resin layer may or may not be in contact with each other. A first example of the multilayer body is one containing an aliphatic polyamide resin layer / polyamide resin layer (stretched film). The multilayer body of the first example also includes a layer structure of aliphatic polyamide resin layer / polyamide resin layer (stretched film) / aliphatic polyamide resin layer. Furthermore, in the multilayer body, although another layer such as an adhesive layer may be interposed between the aliphatic polyamide resin layer and the polyamide resin layer (stretched film), it is preferable that the aliphatic polyamide resin layer and the polyamide resin layer (stretched film) are in contact with each other. Furthermore, in the first example, when the multilayer body has an adhesive layer, it preferably includes a layer structure of aliphatic polyamide resin layer / adhesive layer / polyamide resin layer (stretched film) / adhesive layer / aliphatic polyamide resin layer. In this case, it is preferable that the aliphatic polyamide resin layer and the adhesive layer, and / or the adhesive layer and the polyamide resin layer (stretched film) are in contact with each other. The aliphatic polyamide resin layer may be stretched or unstretched, but is preferably stretched. In practice, it is generally stretched simultaneously with the stretching of the polyamide resin layer (stretched film).

[0013] The aliphatic polyamide resin contained in the aliphatic polyamide resin layer in this embodiment may be either a homopolymer or a copolymer of the monomers constituting the aliphatic polyamide resin. Specifically, the aliphatic polyamide resin may be polycaproamide (polyamide 6), a copolymer of polyhexamethylene adipamide and polycaproamide (polyamide 66 / 6), polyundecaneamide (polyamide 11), polydodecanamide (polyamide 12), polyethylene adipamide (polyamide 26), polytetramethylene succinamide (polyamide 44), polytetramethylene glutamide (polyamide 45), polytetramethylene adipamide (polyamide 46), polytetramethylene suberamide (polyamide 48), polytetramethylene azelamide (polyamide 49), polytetramethylene sebacamide (polyamide 410), polytetramethylene dodecamide (polyamide 412), polypentamethylene succinamide (polyamide 54), polypentamethylene glutamide (polyamide 55), polypentamethylene adipamide (polyamide 56), polypentamethylene suberamide (polyamide 58), polypentamethylene azelamide (polyamide 59), polypentamethylene sebacamide (polyamide 510), polypentamethylene succinamide (polyamide 512 ... Polyhexamethylene dodecamide (Polyamide 512), Polyhexamethylene succinamide (Polyamide 64), Polyhexamethylene glutamide (Polyamide 65), Polyhexamethylene adipamide (Polyamide 66), Polyhexamethylene suberamide (Polyamide 68), Polyhexamethylene azelamide (Polyamide 69), Polyhexamethylene sebacamide (Polyamide 610), Polyhexamethylene dodecamide (Polyamide 612), Polyhexamethylene tetradecamide (Polyamide 614), Polyhexamethylene hexadecaamide Polyhexamethylene octadecamide (polyamide 616), polyhexamethylene octadecamide (polyamide 618), polynonameethylene adipamide (polyamide 96), polynonameethylene suberamide (polyamide 98), polynonameethylene azelamide (polyamide 99), polynonameethylene sebacamide (polyamide 910), polynonameethylene dodecamide (polyamide 912), polydecamethylene adipamide (polyamide 106), polydecamethylene suberamide (polyamide 108), polydecamethylene azelamide (polyamide 109),Examples include polydecamethylene sebacamide (polyamide 1010), polydecamethylene dodecamide (polyamide 1012), polydodecamethylene adipamide (polyamide 126), polydodecamethylene suberamide (polyamide 128), polydodecamethylene azelamide (polyamide 129), polydodecamethylene sebacamide (polyamide 1210), and polydodecamethylene dodecamide (polyamide 1212). Polyamide 6 and polyamide 66 / 6 are preferred, with polyamide 6 being more preferred.

[0014] The aliphatic polyamide resin layer in the first example preferably contains 70% by mass or more of an aliphatic polyamide resin, more preferably 80% by mass or more, even more preferably 90% by mass or more, and may contain 95% by mass or more. The aliphatic polyamide resin layer may contain one kind or two or more kinds of aliphatic polyamide resins, and when two or more kinds are used, the total amount preferably falls within the above range. The aliphatic polyamide resin layer in the first example may contain other components within the scope of the present invention, such as polyolefins and ionomer resins.

[0015] For the aliphatic polyamide resin layer in the first example, the description in paragraphs 0047 to 0079 of WO 2017 / 073560 can be referred to, the contents of which are incorporated herein by reference.

[0016] The adhesive layer in the first example preferably contains an acid-modified polyolefin as an adhesive. The acid-modified polyolefin is preferably an acid-modified polyolefin modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, or maleic anhydride, and more preferably a maleic anhydride-modified polyolefin. The adhesive layer in the first example preferably contains 80% by mass or more of adhesive, more preferably 90% by mass or more, and even more preferably 95% by mass or more. Furthermore, the adhesive layer in the first example may contain other components within the scope of the present invention. For details of the adhesive layer, please refer to paragraph 0015 of JP 2012-035504 A and paragraph 0043 of WO 2015 / 083558 A, the contents of which are incorporated herein by reference.

[0017] In the first example, the thickness of the polyamide resin layer (stretched film) is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, and is preferably 400 μm or less, more preferably 300 μm or less, and even more preferably 150 μm or less. In the first example, the thickness of one aliphatic polyamide resin layer is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, and is preferably 500 μm or less, and even more preferably 300 μm or less. In the first example, if an adhesive layer is present, its thickness is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, and is preferably 200 μm or less, and even more preferably 100 μm or less.

[0018] The first example multilayer body can be produced, for example, according to the description in paragraphs 0080 to 0092 of WO 2017 / 073560, the contents of which are incorporated herein by reference.

[0019] A second example of the layer structure of the multilayer body of this embodiment is a multilayer body in which at least one of the other layers is a layer containing polyolefin (a polyolefin layer). In this embodiment, the polyolefin layer and the polyamide resin layer may or may not be in contact with each other. The multilayer body of the second example preferably has a layer structure of polyolefin layer / polyamide resin layer (stretched film) / polyolefin layer. In this case, the polyolefin layer and the polyamide resin layer (stretched film) are preferably in contact with each other. When the multilayer body of the second example has an adhesive layer, the multilayer body preferably has a layer structure of polyolefin layer / adhesive layer / polyamide resin layer (stretched film) / adhesive layer / polyolefin layer. In this case, the polyolefin layer and the adhesive layer, and / or the adhesive layer and the polyamide resin layer (stretched film) are preferably in contact with each other. The polyolefin layer may be stretched or unstretched, and is preferably stretched. In practice, the polyolefin layer is generally stretched simultaneously with the stretching of the polyamide resin layer (stretched film).

[0020] The polyolefin contained in the polyolefin layer in this embodiment may be either a homopolymer or copolymer of an α-olefin. Furthermore, other monomer components may be copolymerized within the scope of the present invention, and a polymer containing 50 mol% or more of polypropylene units (a polypropylene-based polymer) is preferred. Specific examples of the polyolefin include polyethylene, homopolypropylene, propylene-ethylene random copolymer, and propylene-ethylene block copolymer. Furthermore, the polyolefin may be partly acid-modified polyolefin. By including an acid-modified polyolefin, adhesion to the polyamide resin layer can be improved. The acid-modified polyolefin is preferably an acid-modified polyolefin modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, or maleic anhydride, and more preferably a maleic anhydride-modified polyolefin. In particular, in the second example of the multilayer body, when the polyamide resin layer (stretched film) and the polyolefin layer are in contact with each other, it is preferable that the polyolefin layer contains an acid-modified polyolefin. The content of the acid-modified polyolefin in the polyolefin layer is preferably 1 to 20 mass% of the polyolefin layer.

[0021] The polyolefin layer in the second example preferably contains 80% by mass or more of polyolefin, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The polyolefin layer may contain one kind of polyolefin or two or more kinds of polyolefins, and when two or more kinds of polyolefins are used, the total amount thereof is preferably within the above range. Furthermore, the polyolefin layer in the second example may contain other components within the scope of the present invention. For the polyolefin layer in the second example, the description in paragraph 0014 of JP-A-2012-035504 can be referred to, the contents of which are incorporated herein by reference.

[0022] In the second example, the adhesive layer preferably contains an acid-modified polyolefin as an adhesive. The acid-modified polyolefin is preferably an acid-modified polyolefin modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, or maleic anhydride, and more preferably a maleic anhydride-modified polyolefin. The adhesive layer in the second example preferably contains 80% by mass or more of an adhesive, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The adhesive layer in the second example may contain other components within the scope of the present invention. For details of the adhesive layer, please refer to paragraph 0015 of JP 2012-035504 A and paragraph 0043 of WO 2015 / 083558 A, the contents of which are incorporated herein by reference.

[0023] In the second example, the thickness of the polyamide resin layer (stretched film) is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, and is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less. In the second example, the thickness of the polyolefin layer is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 50 μm or more, and is preferably 2500 μm or less, and even more preferably 2000 μm or less. In the second example, if an adhesive layer is present, its thickness is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, and is preferably 3000 μm or less, and even more preferably 2500 μm or less.

[0024] The multilayer body of the second example can be produced, for example, according to the description in paragraph 0033 of JP-A-2012-035504, the contents of which are incorporated herein by reference.

[0025] A third example of the layer structure of the multilayer body of this embodiment is a multilayer body in which at least one of the other layers is a layer containing an oxygen scavenger (oxygen absorbing layer). In this embodiment, the oxygen absorbing layer and the polyamide resin layer may or may not be in contact with each other. The multilayer body of the third example preferably has any of the layer structures below. Furthermore, the layers shown below may or may not be in contact with each other, but are preferably in contact with each other. Oxygen absorbing layer / Polyamide resin layer (stretched film) Oxygen absorbing layer / adhesive layer / polyamide resin layer (stretched film) Oxygen absorbing layer containing adhesive / Polyamide resin layer (stretched film)

[0026] The oxygen absorbing layer in this embodiment preferably contains an oxygen scavenger and a thermoplastic resin. Examples of oxygen scavenger include those that use a metal powder such as iron powder, a reducing inorganic substance such as an iron compound, a reducing organic substance such as polyhydric phenols, polyhydric alcohols, ascorbic acid or its salts, or a metal complex as the main component of the oxygen absorption reaction. Among these, from the viewpoint of oxygen scavenging performance, iron powder is preferred, iron powder and a metal halide are more preferred, and iron powder with a metal halide attached thereto is even more preferred. The iron powder used in the oxygen scavenger is not particularly limited as long as it can be dispersed in a thermoplastic resin and can cause an oxygen scavenging reaction. Iron powders typically used in oxygen scavenger can be used. Specific examples of iron powder include reduced iron powder, sponge iron powder, atomized iron powder, ground iron powder, electrolytic iron powder, and pulverized iron. Iron powders with low impurity contents such as oxygen and silicon are preferred, and iron powders with a metallic iron content of 95% by mass or more are particularly preferred. The metal halide used in the oxygen scavenger acts catalytically on the oxygen absorption reaction of metallic iron. Preferred examples of the metal include at least one selected from the group consisting of alkali metals, alkaline earth metals, copper, zinc, aluminum, tin, iron, cobalt, and nickel. Particularly preferred are lithium, potassium, sodium, magnesium, calcium, barium, and iron. Preferred examples of the halide include chloride, bromide, and iodide, with chloride being particularly preferred. The amount of metal halide added is preferably 0.1 to 20 parts by mass per 100 parts by mass of the metal. It is preferable that substantially all of the metal halide adheres to the metallic iron, with almost no free metal halide remaining in the oxygen scavenger. When the metal halide effectively acts, 0.1 to 5 parts by mass is sufficient. In a third example, iron powder coated with a metal halide can be suitably used as the oxygen scavenger.

[0027] Specific examples of the thermoplastic resin used in the oxygen absorbing layer include polyolefins such as polyethylene, polypropylene, polybutadiene, and polymethylpentene, elastomers, and modified products thereof, or mixed resins thereof. Of these, it is preferable that 50% by mass or more of the thermoplastic resin used in the oxygen absorbing layer is polypropylene. The mass ratio of the oxygen scavenger to the thermoplastic resin in the oxygen absorbing layer (oxygen scavenger / thermoplastic resin) is preferably 5 / 95 to 50 / 50, more preferably 10 / 90 to 40 / 60. Within this range, good oxygen scavenging performance can be exhibited without adversely affecting the moldability and appearance of the multilayer body. In a third example, the oxygen absorbing layer preferably contains the oxygen scavenger and the thermoplastic resin in total, and more preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more of the oxygen absorbing layer. The oxygen absorbing layer may contain one kind of oxygen scavenger and one kind of thermoplastic resin, or two or more kinds of oxygen scavenger and thermoplastic resin. The oxygen absorbing layer in the third example may contain other components within the scope of the present invention. For the oxygen absorbing layer in the third example, the description in paragraphs 0015 to 0025 of WO 2015 / 083558 can be referred to, the contents of which are incorporated herein by reference.

[0028] In the third example, the adhesive layer preferably contains an acid-modified polyolefin as an adhesive. The acid-modified polyolefin is preferably an acid-modified polyolefin modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, or maleic anhydride, and more preferably a maleic anhydride-modified polyolefin. The adhesive layer in the third example preferably contains 80% by mass or more of an adhesive, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The adhesive layer in the third example may contain other components within the scope of the present invention. For details of the adhesive layer, please refer to paragraph 0015 of JP 2012-035504 A and paragraph 0043 of WO 2015 / 083558 A, the contents of which are incorporated herein by reference.

[0029] In the third example, the thickness of the polyamide resin layer (stretched film) is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less. In the third example, the thickness of the oxygen absorbing layer is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 500 μm or less, and even more preferably 400 μm or less. In the third example, if an adhesive layer is present, its thickness is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, and is preferably 200 μm or less, and even more preferably 100 μm or less.

[0030] The multilayer body of the third example can be produced, for example, as described in paragraph 0047 of WO 2015 / 083558, the contents of which are incorporated herein by reference.

[0031] A fourth example of the layer structure of the multilayer body of this embodiment is a multilayer body in which at least one of the other layers is a metal vapor deposition layer. In this embodiment, the metal vapor deposition layer and the polyamide resin layer may or may not be in contact with each other. The multilayer body of the fourth example preferably has any of the layer structures below. Furthermore, the layers shown below may or may not be in contact with each other, but are preferably in contact with each other. Metal vapor deposition layer / Polyamide resin layer (stretched film) Metal vapor deposition layer / Polyamide resin layer (stretched film) / Polyolefin layer Metal vapor deposition layer / Polyamide resin layer (stretched film) / Adhesive layer / Polyolefin layer Metal vapor deposition layer) / Polyamide resin layer (stretched film) / Adhesive layer / Recycled olefin layer / Olefin layer

[0032] The metal vapor deposition layer in this embodiment is preferably an aluminum vapor deposition layer, which can be formed on (preferably on) the polyamide resin layer (stretched film) by, for example, vacuum deposition. In the vacuum deposition method, high-purity aluminum metal is heated to 1400-1500°C by high-frequency induction heating, direct current heating, or electron beam heating, and evaporated. -4 A vacuum of about torr, for example, about 1.0 × 10 -4 ~5.0×10 -4 This can be done using a vacuum of 1000 torr. The thickness of the aluminum vapor-deposited layer is preferably 20 nm or more, more preferably 25 nm or more, and even more preferably 30 nm or more. The thickness of the aluminum vapor-deposited layer is preferably 100 nm or less, more preferably 95 nm or less, and even more preferably 90 nm or less. In this embodiment, the aluminum vapor deposition layer is less likely to peel off from the polyamide resin layer (stretched film), and pinhole resistance can be improved. For other details of the metal vapor deposition layer, please refer to the description in WO 2018 / 083962, the contents of which are incorporated herein by reference.

[0033] In the multilayer body of the fourth example, when a polyolefin layer is provided, the details thereof are the same as those of the polyolefin layer described in the second example, and the preferred ranges are also the same. In the multilayer body of the fourth example, when an adhesive layer is provided, the details thereof are the same as those of the adhesive layer described in the second example, and the preferred ranges are also the same.

[0034] In the multilayer body of the fourth example, when a recycled olefin layer is provided, it is exemplified by a layer containing recycled polyolefin. An example of the recycled polyolefin is recycled polypropylene. Other details of the recycled olefin layer are the same as those of the polyolefin layer described in the second example.

[0035] Furthermore, the multilayer bodies of the first to fourth examples above may contain other layers within the scope of the present invention. Specific examples include an oxygen permeable layer, a sealant layer, a printed layer, etc. For the oxygen-permeable layer, the description in paragraphs 0011 to 0014 of WO 2015 / 083558 can be referred to, the contents of which are incorporated herein by reference. For the sealant layer, reference may be made to paragraph 0045 of International Publication No. 2015 / 083558, the contents of which are incorporated herein by reference. For the heat seal layer, the description in paragraphs 0037 to 0038 of WO 2018 / 083962 can be referred to, the contents of which are incorporated herein by reference.

[0036] Next, the stretched film (polyamide resin layer) in this embodiment will be described. The stretched film in this embodiment contains more than 60% by mass of polyamide resin (A). By containing polyamide resin (A), a polyamide resin layer having excellent pinhole resistance and oxygen barrier properties can be obtained, and the pinhole resistance and oxygen barrier properties of the multilayer body can be improved. The proportion of polyamide resin (A) in the stretched film (polyamide resin layer) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and may be 99% by mass or more. The stretched film (polyamide resin layer) in this embodiment may contain only one type of polyamide resin (A), or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0037] The polyamide resin (A) contains diamine-derived structural units and dicarboxylic acid-derived structural units, with 70 mol % or more of the diamine-derived structural units being derived from xylylenediamine (preferably meta-xylylenediamine and / or para-xylylenediamine, more preferably meta-xylylenediamine), and 70.1 to 92.0 mol % of the dicarboxylic acid-derived structural units being derived from α,ω-straight-chain aliphatic dicarboxylic acids having 4 to 8 carbon atoms, and 29.9 to 8.0 mol % being derived from α,ω-straight-chain aliphatic dicarboxylic acids having 9 to 12 carbon atoms.

[0038] In the polyamide resin (A), 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine. It is presumed that the use of xylylenediamine causes molecular chain stacking due to the influence of the benzene ring structure, reducing the free volume in the resin and thereby exhibiting high oxygen barrier properties. The diamine-derived structural units in the polyamide resin of this embodiment are preferably 75 mol % or more, more preferably 80 mol % or more, even more preferably 85 mol % or more, still more preferably 90 mol % or more, even more preferably 95 mol % or more, and still more preferably 99 mol % or more derived from xylylenediamine. The upper limit may be 100 mol %. In this embodiment, meta-xylylenediamine and para-xylylenediamine preferably account for 99 mol % or more of the total xylylenediamine. The molar ratio of meta-xylylenediamine to para-xylylenediamine in the xylylenediamine, when the total of meta-xylylenediamine and para-xylylenediamine is 100 mol, is preferably 10 to 100 / 90 to 0, more preferably 30 to 100 / 70 to 0, even more preferably 50 to 100 / 50 to 0, still more preferably 80 to 100 / 20 to 0, even more preferably 90 to 100 / 10 to 0, and still more preferably 95 to 100 / 5 to 0. By increasing the ratio of meta-xylylenediamine, it is possible to suppress an increase in melting point and lower the processing temperature, thereby more effectively suppressing the occurrence of scorching and gelation.

[0039] Examples of diamines other than xylylenediamine that can be used as the raw material diamine component of the polyamide resin in this embodiment include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; 1,3-bis(aminomethyl)cyclohexane; Examples include alicyclic diamines such as 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane; and diamines having an aromatic ring such as paraxylylenediamine, bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene, and these can be used alone or in combination of two or more.

[0040] The polyamide resin (A) in this embodiment contains diamine-derived structural units and dicarboxylic acid-derived structural units, with 70.1 to 92.0 mol % of the dicarboxylic acid-derived structural units being derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 8 carbon atoms and 29.9 to 8.0 mol % being derived from α,ω-linear aliphatic dicarboxylic acids having 9 to 12 carbon atoms. The use of α,ω-linear aliphatic dicarboxylic acids having 4 to 8 carbon atoms increases the amide bond density, tending to produce polyamide resins with excellent oxygen barrier properties. Furthermore, the use of α,ω-linear aliphatic dicarboxylic acids having 9 to 12 carbon atoms lowers the melting point, thereby lowering the extrusion temperature and suppressing scorching and gel formation, and also tends to produce polyamide resins with improved flexibility and excellent pinhole resistance.

[0041] Examples of the α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 8 carbon atoms include succinic acid, glutaric acid, pimelic acid, adipic acid, and suberic acid, with adipic acid being preferred. Examples of α,ω-linear aliphatic dicarboxylic acids having 9 to 12 carbon atoms include azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid, with sebacic acid being preferred. Sebacic acid can be derived from plant materials, which can increase the bio-based content of the resin.

[0042] Examples of dicarboxylic acid components other than the above-mentioned α,ω-linear aliphatic dicarboxylic acids having 4 to 12 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and these can be used alone or in combination of two or more.

[0043] The proportion of the α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms (preferably adipic acid) in the dicarboxylic acid-derived structural units is preferably 75.0 mol % or more, and more preferably 78.0 mol % or more. By making the proportion equal to or greater than the lower limit, gas barrier properties tend to be further improved. Furthermore, the proportion of the α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms is preferably 88.0 mol % or less, more preferably 86.0 mol % or less, even more preferably 85.0 mol % or less, and even more preferably 84.0 mol % or less. By making the proportion equal to or less than the upper limit, flexibility is improved and pinhole resistance tends to be excellent.

[0044] The proportion of the α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms (preferably sebacic acid) in the dicarboxylic acid-derived structural units is preferably 25.0 mol% or less, and more preferably 22.0 mol% or less. By making it equal to or less than the upper limit, oxygen barrier properties tend to be further improved. Furthermore, the proportion of the α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms is preferably 12.0 mol% or more, more preferably 14.0 mol% or more, even more preferably 15.0 mol% or more, and may be 16.0 mol% or more. By making it equal to or more than the lower limit, flexibility is improved and pinhole resistance tends to be more excellent.

[0045] The dicarboxylic acid-derived structural units, consisting of structural units derived from an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 8 carbon atoms (preferably adipic acid) and structural units derived from an α,ω-straight-chain aliphatic dicarboxylic acid having 9 to 12 carbon atoms (preferably sebacic acid), preferably account for at least 88 mol%, more preferably at least 90 mol%, even more preferably at least 91 mol%, still more preferably at least 93 mol%, even more preferably at least 95 mol%, still more preferably at least 97 mol%, and particularly preferably at least 99 mol%, of all dicarboxylic acid-derived structural units. The upper limit of this total may be 100 mol%. The structural units derived from an α,ω-straight-chain aliphatic dicarboxylic acid having 4 to 8 carbon atoms and the structural units derived from an α,ω-straight-chain aliphatic dicarboxylic acid having 9 to 12 carbon atoms may each be used alone or in combination of two or more. When two or more types are used, it is preferable that the total amount is in the above range.

[0046] A particularly preferred form of the polyamide resin in this embodiment is a polyamide resin that contains diamine-derived structural units and dicarboxylic acid-derived structural units, in which 95 mol % or more of the diamine-derived structural units are derived from metaxylylenediamine, 80.0 to 84.0 mol % of the dicarboxylic acid-derived structural units are derived from adipic acid and 20.0 to 16.0 mol % are derived from sebacic acid, and the total of the adipic acid-derived structural units and the sebacic acid-derived structural units is 95 mol % or more of the dicarboxylic acid-derived structural units.

[0047] The polyamide resin of this embodiment contains dicarboxylic acid-derived structural units and diamine-derived structural units, but may also contain structural units other than the dicarboxylic acid-derived structural units and diamine-derived structural units, as well as other moieties such as terminal groups. Examples of other structural units include, but are not limited to, structural units derived from lactams such as ε-caprolactam, valerolactam, laurolactam, and undecalactam, and aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. Furthermore, the polyamide resin of this embodiment may contain trace components such as additives used in the synthesis. In the polyamide resin (A) of the present embodiment, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, even more preferably 98% by mass or more, and still more preferably 99% by mass or more of all structural units excluding terminal groups are composed of structural units derived from dicarboxylic acids and structural units derived from diamines.

[0048] In this embodiment, the polyamide resin (A) preferably has a number average molecular weight (Mn) of 5,000 or more, more preferably 6,000 or more, and even more preferably 10,000 or more. The upper limit of Mn is preferably 100,000 or less, more preferably 50,000 or less, and even more preferably 30,000 or less. Within this range, the heat resistance, elastic modulus, dimensional stability, and moldability are improved. The number average molecular weight is measured according to the description in paragraph 0057 of WO 2019 / 026499.

[0049] The lower limit of the relative viscosity of the polyamide resin (A) in this embodiment is preferably 2.0 or more, more preferably 2.1 or more, and even more preferably 2.3 or more, while the upper limit of the relative viscosity of the polyamide resin (A) is preferably 4.0 or less, more preferably 3.9 or less, and even more preferably 3.8 or less. The relative viscosity of the polyamide resin (A) is measured under the conditions of JIS K 69020-2.

[0050] The polyamide resin (A) used in this embodiment is preferably produced by melt polycondensation (melt polymerization) using a phosphorus atom-containing compound as a catalyst, or by a pressure salt method, and more preferably by a melt polycondensation method. A preferred melt polycondensation method involves adding a raw diamine dropwise to a molten dicarboxylic acid, raising the temperature under pressure, and polymerizing the resulting dicarboxylic acid while removing the condensed water. A preferred pressure salt method involves raising the temperature of a salt composed of the raw diamine and the resulting dicarboxylic acid in the presence of water under pressure, and polymerizing the resulting salt in a molten state while removing the added water and condensed water. Known catalysts can be used, but examples of sodium-containing catalysts include sodium hypophosphite, sodium phosphite, and sodium hydrogen phosphite. Examples of calcium-containing catalysts include calcium hypophosphite and calcium phosphite. In this embodiment, a polymerization rate regulator may be added in addition to the phosphorus atom-containing compound. Examples of the polymerization rate regulator include alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal acetates, and alkaline earth metal acetates, with alkali metal acetates being preferred.

[0051] The polyamide resin layer in the present embodiment may consist of only one or more polyamide resins (A), or may contain other components. Other components that may be added as needed include polyamide resins other than the polyamide resin (A), thermoplastic resins other than polyamide resins, oxidation reaction accelerators, reinforcing materials (fillers), antioxidants (particularly heat stabilizers) such as heat stabilizers and weather stabilizers, impact modifiers, flame retardants, flame retardant assistants, mold release agents, anti-dripping agents, delustering agents, UV absorbers, plasticizers, antistatic agents, color inhibitors, anti-gelling agents, nucleating agents, etc. Each of these additives may be one type or two or more types.

[0052] The other polyamide resin that may be contained in the polyamide resin layer in this embodiment may be an aliphatic polyamide resin or a semi-aromatic polyamide resin. Examples of aliphatic polyamide resins include polyamide 6, polyamide 66, polyamide 46, polyamide 6 / 66 (a copolymer consisting of a polyamide 6 component and a polyamide 66 component), polyamide 610, polyamide 612, polyamide 410, polyamide 1010, polyamide 11, polyamide 12, polyamide 1012, and polyamide 9C (a polyamide consisting of a mixed diamine consisting of 1,9-nonanediamine and 2-methyl-1,8-octanediamine and 1,4-cyclohexanedicarboxylic acid). Examples of semi-aromatic polyamide resins include polyamide 4T, polyamide 6T, polyamide 6I, polyamide 6T / 6I, polyamide 9T, polyamide 10T, and polyamide 9N.

[0053] When the polyamide resin layer in this embodiment contains another polyamide resin, the content thereof is preferably 1 part by mass or more, and may be 10 parts by mass or more, and is preferably 66 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the polyamide resin (A). The polyamide resin layer in this embodiment may contain only one type of other polyamide resin, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0054] The polyamide resin layer in this embodiment may contain an oxidation reaction accelerator, which can enhance the oxygen absorption of the polyamide resin layer in this embodiment. The oxidation reaction accelerator may be any one that exhibits an oxidation reaction acceleration effect, but from the viewpoint of accelerating the oxidation reaction of the polyamide resin (A), a compound containing a transition metal element is preferred. The transition metal element is preferably at least one selected from the transition metals of Group VIII of the periodic table, manganese, copper, and zinc, and from the viewpoint of effectively exhibiting oxygen absorption capacity, at least one selected from cobalt, iron, manganese, and nickel is more preferred, with cobalt being even more preferred. When the oxidation reaction accelerator contains a transition metal element, the content thereof is preferably 10 ppm by mass or more and preferably 1000 ppm by mass or less, in terms of the transition metal concentration in the polyamide resin (A), from the viewpoint of accelerating the oxidation reaction of the polyamide resin (A) and enhancing the oxygen absorption capacity of the molded article. The transition metal concentration in the molded article can be measured by a known method, for example, ICP emission spectrometry. The oxidation reaction accelerators may be used singly or in combination of two or more. When two or more types are used in combination, the total amount is preferably within the above range.

[0055] The oxygen permeability (OTR, unit: cc / m) of the stretched film in this embodiment 2 ·atm·day) is 0.2cc / m 2 ·atm·day or less is preferable, and 0.1cc / m 2 The lower limit is 0 cc / m 2 Atm·day or more is ideal, but 0.0001cc / m 2 ·atm·day is practical. The oxygen permeability is measured as described in the Examples section below.

[0056] The stretched film in this embodiment is obtained by stretching an unstretched polyamide resin layer. By stretching, the oxygen barrier property of the polyamide resin layer can be improved. The stretching may be uniaxial or biaxial, with biaxial stretching being preferred. The biaxial stretching may be sequential or simultaneous. Furthermore, in the case of uniaxial stretching, the stretching ratio is preferably 1.1 times or more, more preferably 2 times or more, even more preferably 2.5 times or more, and even more preferably 3.0 times or more. There is no particular upper limit, but it is preferably 20.0 times or less. In the case of biaxial stretching, the stretching ratio is preferably 1.1 times or more, more preferably 2.0 times or more, even more preferably 4.0 times or more, and even more preferably 6.0 times or more. There is no particular upper limit, but it is preferably 20.0 times or less.

[0057] The unstretched polyamide resin layer may be stretched after being formed into a multilayer body with other layers, or the unstretched polyamide resin layer may be stretched and then laminated with other layers. When an unstretched polyamide resin layer is stretched, the stretching method can be determined by referring to paragraphs 0049 to 0053 of WO 2017 / 010390, the contents of which are incorporated herein by reference. Furthermore, when the unstretched polyamide resin layer is combined with other layers to form a multilayer body, the description in paragraphs 0080 to 0092 of WO 2017 / 073560 can be taken into consideration, the contents of which are incorporated herein by reference. In addition, for the production of stretched films and multilayer bodies, the descriptions in paragraphs 0025 to 0030 of Patent Publication No. 2019 / 208687 can be taken into consideration within the scope of the present invention, and the contents of these are incorporated into this specification. The film can be produced by extruding a resin composition comprising the polyamide resin (A) and other components blended as necessary. Here, when producing the polyamide resin (A), for example, the molding temperature can be lowered by 10°C or more (preferably 20°C or more, and, for example, 30°C or less) than when the structural units derived from an α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms in the polyamide resin (A) are replaced with an equimolar amount of structural units derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms. As a result, gelation of the resulting film can be more effectively suppressed.

[0058] The multilayer body of this embodiment is preferably used as a packaging material or a container, for example, for food, medical, or cosmetic use. Contents that can be filled or packaged in the packaging material or container of this embodiment include confectioneries such as rice crackers, bean snacks, nuts, biscuits, cookies, wafer snacks, marshmallows, pies, semi-dried cakes, candy, and snacks; staple foods such as bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, porridge, porridge, packaged rice cakes, and cereal foods; pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, processed wild vegetables, jams, peanut cream, salads, frozen vegetables, and processed potato products; processed livestock products such as ham, bacon, sausages, processed chicken products, and corned beef; fish ham, fish sausage, and fish paste products. These include processed seafood products such as kamaboko, nori seaweed, tsukudani (simmered foods in soy sauce), bonito flakes, salted fish, smoked salmon, and spicy mentaiko; fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries; vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes; cooked foods such as frozen and chilled prepared dishes, including hamburgers, meatballs, fried seafood, gyoza, and croquettes; dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula; soups, jellies, liquid seasonings, retort curry, pet food, nursing care food, and emergency food; tobacco, disposable hand warmers, medicines, and cosmetics. [Example]

[0059] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0060] raw material PA6: Polyamide 6, manufactured by Ube Industries, Ltd., 1024B PP: Polypropylene, manufactured by Japan Polypropylene Corporation, FY6 Adhesive PP: Adhesive polypropylene, manufactured by Dow Chemical Company, Fusabond P353 MXD6: Polyamide resin synthesized from metaxylene diamine and adipic acid, manufactured by Mitsubishi Gas Chemical Company, Inc., S6011

[0061] MXD610(90 / 10): Polyamide resin synthesized from metaxylene diamine, adipic acid, and sebacic acid (molar ratio of adipic acid to sebacic acid is 90:10), synthesized according to the following synthesis example. <Synthesis Example of MXD610(90 / 10)> Into a reaction vessel equipped with a stirrer, partial condenser, total condenser, thermometer, dropping funnel, nitrogen inlet tube, and strand die, 10,000 g (68 mol) of adipic acid, 1,538 g (7.6 mol) of sebacic acid, 0.33 g of sodium hypophosphite monohydrate (NaH2PO2·H2O) (5 ppm in terms of phosphorus atom concentration in the polyamide resin), and 0.13 g of sodium acetate were charged. After sufficient nitrogen substitution, the vessel was filled with nitrogen to an internal pressure of 0.4 MPa, and then heated to 190°C while stirring the system under a slight nitrogen stream. 10,500 g (77 mol) of metaxylene diamine was added dropwise thereto under stirring, and the internal temperature of the system was continuously increased while removing the generated condensation water outside the system. After the completion of the dropwise addition of metaxylene diamine, the internal temperature was raised. When it reached 255°C, the inside of the reaction vessel was depressurized, and the internal temperature was further raised to continue the melt polycondensation reaction at 260°C for 10 minutes. Then, the system was pressurized with nitrogen, and the obtained polymer was taken out from the strand die and pelletized to obtain polyamide MXD610(90 / 10). The obtained resin was dried in a batch dryer at 180°C for 2 hours to increase the degree of polymerization, resulting in a relative viscosity of 2.7.

[0062] MXD610(84 / 16): Polyamide resin synthesized from metaxylene diamine, adipic acid, and sebacic acid (molar ratio of adipic acid to sebacic acid is 84:16), synthesized according to the following synthesis example. <Synthesis Example of MXD610(84 / 16)> Into a reaction vessel equipped with a stirrer, a partial condenser, a total condenser, a thermometer, a dropping funnel, a nitrogen inlet tube, and a strand die, 10,000 g (68 mol) of adipic acid, 2,636 g (13 mol) of sebacic acid, 0.36 g of sodium hypophosphite monohydrate (NaH2PO2·H2O) (5 ppm by mass in terms of the phosphorus atom concentration in the polyamide resin), and 0.14 g of sodium acetate were blended. After sufficient nitrogen substitution, nitrogen was filled to an internal pressure of 0.4 MPa, and then the system was heated to 190 °C while stirring under a small amount of nitrogen stream. To this, 11,360 g (83 mol) of metaxylylenediamine was added dropwise with stirring, and the internal temperature of the system was continuously increased while removing the generated condensed water outside the system. After the completion of the dropwise addition of metaxylylenediamine, the internal temperature was raised. When it reached 255 °C, the inside of the reaction vessel was depressurized, and the internal temperature was further raised to continue the melt polycondensation reaction at 260 °C for 10 minutes. Then, the system was pressurized with nitrogen, and the obtained polymer was taken out from the strand die and pelletized to obtain polyamide MXD610(84 / 16). The obtained resin was dried in a batch dryer at 180 °C for 2 hours to increase the degree of polymerization to a relative viscosity of 2.7.

[0063] MXD610(80 / 20): A polyamide resin synthesized from metaxylylenediamine, adipic acid, and sebacic acid (the molar ratio of adipic acid to sebacic acid is 80:20), was synthesized according to the following synthesis example. <Synthesis Example of MXD610(80 / 20)> Into a reaction vessel equipped with a stirrer, a partial condenser, a total condenser, a thermometer, a dropping funnel, a nitrogen inlet tube, and a strand die, 10,000 g (68 mol) of adipic acid, 3,460 g (17 mol) of sebacic acid, 0.38 g of sodium hypophosphite monohydrate (NaH2PO2·H2O) (5 ppm by mass in terms of the phosphorus atom concentration in the polyamide resin), and 0.15 g of sodium acetate were blended. After sufficient nitrogen substitution, nitrogen was filled to an internal pressure of 0.4 MPa, and then the system was heated to 190 °C while stirring under a small amount of nitrogen stream. To this, 11,813 g (87 mol) of metaxylylenediamine was added dropwise with stirring, and while removing the generated condensation water out of the system, the temperature inside the system was continuously increased. After the dropwise addition of metaxylylenediamine was completed, the internal temperature was raised. When it reached 255 °C, the inside of the reaction vessel was depressurized, and the internal temperature was further raised to continue the melt polycondensation reaction at 260 °C for 10 minutes. Then, the system was pressurized with nitrogen, and the obtained polymer was taken out from the strand die and pelletized to obtain polyamide MXD610(80 / 20). The obtained resin was dried in a batch dryer at 180 °C for 2 hours, and by increasing the degree of polymerization, the relative viscosity was made 2.7.

[0064] MXD610(70 / 30): A polyamide resin synthesized from metaxylylenediamine, adipic acid, and sebacic acid (the molar ratio of adipic acid to sebacic acid is 70:30), was synthesized according to the following synthesis example. <Synthesis Example of MXD610(70 / 30)> Into a reaction vessel equipped with a stirrer, a partial condenser, a total condenser, a thermometer, a dropping funnel, a nitrogen inlet tube, and a strand die, 10,000 g (68 mol) of adipic acid, 5,931 g (29 mol) of sebacic acid, 0.44 g of sodium hypophosphite monohydrate (NaH2PO2·H2O) (5 ppm in terms of the phosphorus atom concentration in the polyamide resin), and 0.17 g of sodium acetate were blended. After sufficient nitrogen substitution, nitrogen was filled to an internal pressure of 0.4 MPa, and the system was heated to 190 °C while stirring under a small amount of nitrogen flow. To this, 13,500 g (99 mol) of metaxylylenediamine was added dropwise with stirring, and while removing the generated condensation water out of the system, the temperature inside the system was continuously increased. After the dropwise addition of metaxylylenediamine was completed, the internal temperature was raised. When it reached 255 °C, the inside of the reaction vessel was depressurized, and the internal temperature was further raised to continue the melt polycondensation reaction at 260 °C for 10 minutes. Then, the system was pressurized with nitrogen, and the obtained polymer was taken out from the strand die and pelletized to obtain polyamide MXD610(70 / 30). The obtained resin was dried in a batch dryer at 180 °C for 2 hours, and by increasing the degree of polymerization, the relative viscosity was made 2.7.

[0065] Example 1 <Production of single-layer stretched film (polyamide resin layer)> The obtained polyamide resin was fed to a single-screw extruder equipped with a T-die (manufactured by Plastics Engineering Research Institute, screw diameter 30 mm) and melt-extruded through the die at an extrusion temperature of 240° C. and a flow path temperature of 240° C. Specifically, polyamide resin (A) was extruded to obtain films with a width of 175 mm and thicknesses of 140 μm and 250 μm. The resulting 140 μm thick film was cut into 120 mm squares. Subsequently, using a batch-type biaxial stretching device (tenter method, EX10-S5, manufactured by Toyo Seiki Seisakusho Co., Ltd.), the film was stretched in both MD and TD directions while heated in an air atmosphere at 100°C, with a stretch ratio of 3.0 in MD and 3.0 in TD, for a total stretch ratio of 9.0, to obtain a stretched film with a thickness of 15 μm. During this stretching process, a relaxation operation was performed midway, with an MD relaxation rate of 2.5% and a TD relaxation rate of 2.5%. After stretching, the film was heat-set. The heat-set temperature was 140°C, and the heat-set time was 45 seconds, to obtain a monolayer stretched film. The thickness of the obtained monolayer stretched film was 15 μm.

[0066] <Production of multilayer stretched film (multilayer body)> Polyamide 6 (PA6) and MXD610 were extruded at 240°C using two single-screw extruders (Plastics Engineering Research Institute, screw diameter 40 mm) and a multilayer film molding machine equipped with a T-die and a flow path for forming a two-type, two-layer multilayer structure. A multilayer structure (multilayer film) consisting of a polyamide 6 layer (PA6 layer) and a polyamide resin (A) (MXD610) layer was formed at an extrusion temperature of 240°C and a post-lamination flow path temperature of 240°C. Each layer was 70 μm thick, and the total thickness of the film layers was 140 μm. The resulting film was cut into 120 mm squares. Subsequently, using a batch-type biaxial stretching device (tenter method, EX10-S5, Toyo Seiki Seisakusho Co., Ltd.), the film was stretched in both MD and TD directions while heated at 100°C in an air atmosphere, with a stretch ratio of 3.0 in MD, 3.0 in TD, and a total stretch ratio of 9.0, to obtain a 15 μm-thick stretched film. During this stretching process, a relaxation operation was performed with an MD relaxation rate of 2.5% and a TD relaxation rate of 2.5%. After stretching, the film was heat-set at a temperature of 170°C for 45 seconds to obtain a stretched multilayer film.

[0067] <Oxygen transmission rate (OTR)> The obtained single-layer stretched film (polyamide resin layer) was measured for oxygen permeability (OTR, unit: cc / m) by the isobaric method in an atmosphere of 23°C and relative humidity (RH) 60%. 2 The pressure of the oxygen atmosphere was 1 atm, and the measurement time was 24 hours (1 day). The oxygen transmission rate (OTR) was measured using an oxygen transmission rate measuring device (manufactured by MOCON, "OX-TRAN (registered trademark) 2 / 21"). The evaluation was carried out according to the following classification, and the results are shown in Table 1 below. A: 0.1cc / m 2 ·atm·day or less B: 0.1cc / m 2 ·atm·day super 0.2cc / m 2 ·atm·day or less C: 0.2cc / m 2 ·atm·day super 0.3cc / m 2 ·atm·day or less

[0068] <Pinhole resistance> The obtained stretched multilayer film was cut into 25 cm squares and attached to a pinhole resistance tester. The film was subjected to a 440° twisting motion and a 65 mm linear motion at a rate of 40 times / min, and the film was bent 3,000 times. The number of pinholes in the film after bending was measured using a pinhole tester. 2 The number of pinholes per 100cm of film was calculated. 2 The number of pinholes per pixel is calculated as follows: Number of pinholes (pcs / 100cm 2 ) = total number of pinholes (pcs) / effective test area (cm 2 ) x 100 In this example, a Gelbo Flex Tester manufactured by Rigaku Corporation was used as the pinhole resistance tester, and a POROSCOPE DC manufactured by Fischer was used as the pinhole inspection machine. The evaluation was carried out according to the following classification, and the results are shown in Table 1 below. A: 5 or less B: 6~9 pieces C: 10 or more

[0069] <Gelling prevention> In the present invention, the gel formation suppression effect of polyamide resins was evaluated by comparing the gel fractions of polyamide resins heated in a molten state under high pressure for a fixed time and at a fixed temperature, simulating the conditions to which polyamide resins are exposed during molding. When pressurized and heated resins were immersed in hexafluoroisopropanol (HFIP) for 24 hours, the ungelled resin completely dissolved, while the gelled resin remained as a swollen insoluble component. In this example, the gel fraction was calculated from the insoluble component. In the present invention, the gel fraction refers to the percentage obtained by dividing the mass of the residue obtained by vacuum filtering the insoluble component through a membrane filter and drying it by the mass of the resin, which was weighed before immersion in HFIP.

[0070] <<Gel fraction measurement>> The monolayer unstretched film (250 μm thick) obtained above was cut into a circle with a diameter of 30 mm, and four of these were produced (hereinafter referred to as "circular films"). Circular films 11 were stacked concentrically, and as shown in Figure 2, the concentrically stacked circular films were inserted into the hole of a 1 mm thick, 120 × 120 mm polytetrafluoroethylene sheet 12 with a hole cut out to a diameter of 30 mm, to obtain Sheet A. Sheet A was sandwiched between two 1 mm thick, 120 × 120 mm polytetrafluoroethylene sheets 13, 13. Next, sheet A sandwiched between polytetrafluoroethylene sheets was placed in the center of a 15 mm thick x 150 mm x 150 mm metal plate 14 having a 120 mm x 120 mm groove 3 mm deep in the center, and then sandwiched between two 15 mm thick x 150 mm x 150 mm metal plates 15 on both sides, and then metal plates 14 and 15 were fixed in place with bolts. Next, a preheated heat press was used to press the sheet at 30 kg / cm 2 The metal plates were sandwiched under a pressure of 72, 96, 120, 144, and 160°C for a predetermined time at the melting point of each polyamide resin + 30°C. After each predetermined time had elapsed, the metal plate was removed and rapidly cooled. Once it had cooled sufficiently to room temperature, Sheet A was removed, and the 1 mm thick circular film inside was taken out.

[0071] The circular film was then dried in a thermostatic oven at 60°C for 30 minutes, and 100 mg of the dried sample was immediately weighed. The weighed retained sample was immersed in 10 mL of hexafluoroisopropanol (HFIP) with a purity of 99% or higher for 24 hours and then filtered under reduced pressure through a pre-weighed polytetrafluoroethylene membrane filter with a 300 μm pore size. The residue remaining on the membrane filter was washed three times with 2 mL of HFIP, and the filter with the residue attached was then dried in a thermostatic oven at 60°C for 30 minutes. The total mass of the dried residue and filter was weighed, and the amount of HFIP-insoluble components (gel content) in the retained sample was calculated from the difference between this and the pre-weighed mass of the membrane filter. The gel fraction was calculated as the mass % of the HFIP-insoluble components relative to the retained sample before immersion in HFIP. The evaluation for each heating time was carried out three times, and the average value was taken as the gel fraction for each heating time. The heating time at which the gel fraction reached 10% or more was investigated using the above measurement method, and the evaluation classification was as follows: A: More than 168 hours B: 96 hours or more but less than 168 hours C: Less than 96 hours The results are shown in Table 1 below.

[0072] Comparative Example 1 The same procedures as in Example 1 were carried out except that the types of resins used in the other layers and the type of polyamide resin (A) were changed as shown in Table 1 and the extrusion temperature was changed to 260°C.

[0073] Examples 2 and 3, Comparative Examples 1 and 2 The same procedures were carried out as in Example 1, except that the types of resins used in the other layers and the type of polyamide resin (A) were changed as shown in Table 1.

[0074] Examples 4 and 5 <Manufacturing of multilayer bodies> The polyamide resins listed in Table 1, PP, and adhesive PP were extruded at 240°C using three single-screw extruders (Plastic Engineering Research Institute, 40 mm screw diameter) and a multilayer film molding machine equipped with a T-die and a flow path for forming a three-type, three-layer multilayer structure. A multilayer structure (multilayer film) consisting of a PP layer, adhesive PP layer, and polyamide resin layer was formed at an extrusion temperature of 240°C and a post-lamination flow path temperature of 240°C. The polyamide resin layer was 65 μm thick, the PP layer was 65 μm thick, and the adhesive PP layer was 10 μm thick, resulting in a total film thickness of 140 μm. The resulting film was cut into 120 mm squares. The film was then stretched in both MD and TD directions using a batch-type biaxial stretching device (tenter method, EX10-S5, Toyo Seiki Seisakusho Co., Ltd.) while heated in an air atmosphere at 100°C, with a stretch ratio of 3.0 in MD, 3.0 in TD, and a total stretch ratio of 9.0, to obtain a 15 μm-thick stretched multilayer film. During this stretching process, a relaxation operation was performed with an MD relaxation rate of 2.5% and a TD relaxation rate of 2.5%. After stretching, heat setting was performed at a heat setting temperature of 140°C for 45 seconds to obtain a multilayer body (stretched multilayer film). The pinhole resistance of the obtained multilayer film was evaluated in the same manner as above. The OTR of the stretched film was measured in the same manner as in Example 1 for monolayer stretched films in which the type of polyamide resin used was changed. The results are shown in Table 1 below.

[0075] [Table 1]

[0076] The ratio of a1 to a2 in Table 1 above is a molar ratio. The unit of oxygen transmission rate (OTR) is: cc / m 2 ·atm·day. As is clear from the above results, the multilayer bodies of the present invention had excellent oxygen barrier properties and pinhole resistance (Examples 1 to 5). Furthermore, gelation was suppressed. In contrast, when MXD6 was used in the polyamide resin layer (Comparative Example 1), pinhole resistance was poor, and gelation was not sufficiently suppressed. Furthermore, when the polyamide resin used in the polyamide resin layer had a high degree of modification with an α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms (Comparative Example 2), the barrier properties were poor. [Explanation of symbols]

[0077] 1 Multilayer body 2 Polyamide resin layer (stretched film) 3 Other layers 11. Circular Film Polytetrafluoroethylene sheet with 12 holes 13 Polytetrafluoroethylene sheet 14 Metal plate with grooves 15 metal plate

Claims

1. The polyamide resin (A) may consist of only the polyamide resin (A), a stretched film (excluding those containing a transition metal compound) containing a polyamide resin (A) in a proportion of 95% by mass or more and consisting of only the polyamide resin (A) and at least one additive selected from the group consisting of an oxidation reaction accelerator, a reinforcing material, an antioxidant, an impact resistance modifier, a flame retardant, a flame retardant aid, a release agent, an anti-dripping agent, a delustering agent, an ultraviolet absorber, a plasticizer, an antistatic agent, a coloring inhibitor, an anti-gelling agent, and a nucleating agent; The stretched film has a layer other than the layer, The polyamide resin (A) contains diamine-derived structural units and dicarboxylic acid-derived structural units, and 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70.1 to 92.0 mol % of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms and 29.9 to 8.0 mol % are derived from an α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms. Multilayered body.

2. 2. The multilayer body according to claim 1, wherein at least one of the other layers is a layer comprising polyamide 6 and / or polyamide 6 / 66.

3. 3. The multilayer body according to claim 1, wherein at least one of the other layers is a layer containing a polyolefin.

4. The multilayer body according to any one of claims 1 to 3, wherein 75.0 to 88.0 mol % of the dicarboxylic acid-derived structural units are derived from a straight-chain α,ω-aliphatic dicarboxylic acid having 4 to 8 carbon atoms, and 25.0 to 12.0 mol % are derived from a straight-chain α,ω-aliphatic dicarboxylic acid having 9 to 12 carbon atoms.

5. The multilayer body according to any one of claims 1 to 4, wherein the α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms comprises adipic acid, and the α,ω-linear aliphatic dicarboxylic acid having 9 to 12 carbon atoms comprises sebacic acid.

6. The multilayer body according to any one of claims 1 to 5, wherein 70 mol% or more of the diamine-derived constitutional units are derived from metaxylylenediamine.

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