Polyamide resin composition, film and film laminate containing the same, and pellet mixture

Abstract

To provide a polyamide resin composition which gives a film that prevents aggregation of appearance caused by a film gel and is excellent in pinhole resistance under a low temperature environment, and a film and a film laminate including the same.SOLUTION: A polyamide resin composition contains 86.4-99.2 mass% of a polyamide resin (A), 0.1-10.0 mass% of an ethylene / α-olefin copolymer (B), and 0.1-10.0 mass% of a metal salt (C) of an ethylene / methacrylic acid copolymer, in 100 mass% of the polyamide resin composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polyamide resin composition, a film and a film laminate containing the same, and a pellet mixture. [Background technology]

[0002] A film made of a polyamide resin composition (hereinafter, sometimes referred to as a "polyamide film") is excellent in various properties such as gas barrier properties, toughness, pinhole resistance, heat resistance, and transparency. For this reason, polyamide films are widely used in various fields. As an example, polyamide films are used as packaging materials for food and medicine.

[0003] Among polyamide films used for food packaging materials, polyamide films stored in low-temperature environments, for example, polyamide films used for frozen foods, are required to have excellent pinhole resistance in low-temperature environments. In addition, polymer degradation products (hereinafter sometimes referred to as "film gel") may occur when polyamide films are molded. Since the occurrence of film gel deteriorates the appearance of the polyamide film, there is a demand to reduce the amount of film gel contained in the polyamide film. Since film appearance is particularly required for food packaging applications, materials that minimize the amount of film gel generation are required.

[0004] Patent Document 1 discloses a polyamide-based multilayer film having at least one saponified ethylene-vinyl acetate copolymer layer as a barrier layer and at least one polyamide layer, and in the examples, a multilayer film including a polyamide layer containing 6-nylon, modified ethylene-vinyl acetate copolymer, ethylene / methacrylic acid copolymer ionomer, antioxidant, and aromatic nylon in a predetermined ratio is disclosed. It is shown that the multilayer film can be boiled and retorted without whitening of the film, and has excellent mechanical strength, pinhole resistance, and gas barrier properties.

[0005] Patent Document 2 discloses a biaxially stretched polyamide film containing 2 to 5% by mass of an ethylene copolymer, at least on one side of which is provided a resin layer containing a vinylidene chloride copolymer, and discloses that the film has 10 or less pinholes in a 1000-time repeated bending fatigue test in an atmosphere at 5°C. Examples of the ethylene copolymer include a terpolymer of ethylene-acrylic acid ester-maleic anhydride, an ethylene-(meth)acrylic acid copolymer, or an ionomer thereof. The polyamide film of Patent Document 2 is shown to have excellent gas barrier properties and pinhole resistance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2004 / 113071 [Patent Document 2] JP 2014-014976 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, although the polyamide-based multilayer films in Patent Documents 1 and 2 have excellent pinhole resistance, they suffer from poor appearance due to film gel that occurs during film formation, and there is room for improvement.

[0008] The present invention aims to provide a polyamide resin composition that provides a film that is free from deterioration of appearance due to film gel and has excellent pinhole resistance in a low-temperature environment, and a film and a film laminate using the same. Another aim of the present invention is to provide a pellet mixture that is suitably used for producing the polyamide resin composition, the film, and the film laminate. [Means for solving the problem]

[0009] The present invention relates to the following [1] to

[13] . [1] A polyamide resin composition comprising, based on 100 mass% of the polyamide resin composition, 86.4 to 99.2 mass% of a polyamide resin (A), 0.1 to 10.0 mass% of an ethylene / α-olefin copolymer (B), and 0.1 to 10.0 mass% of a metal salt of an ethylene / methacrylic acid copolymer (C). [2] The polyamide resin composition according to [1], wherein the polyamide resin (A) is selected from the group consisting of polyamide 6, polyamide 6 / 66, polyamide 6 / 12 and polyamide 6 / 66 / 12. [3] The polyamide resin composition according to [1] or [2], wherein a mass ratio (C / B) of the metal salt of ethylene / methacrylic acid copolymer (C) to the ethylene / α-olefin copolymer (B) is 0.04 to 0.60. [4] The polyamide resin composition according to any one of [1] to [3], further comprising 0.01 to 0.6 mass% of an antioxidant based on 100 mass% of the polyamide resin composition, the antioxidant being at least one selected from the group consisting of phenol-based compounds, phosphorus-based compounds, and sulfur-based compounds. [5] The polyamide resin composition according to any one of [1] to [4], further comprising an antiblocking agent. [6] A polyamide film comprising the polyamide resin composition according to any one of [1] to [5]. [7] The polyamide film according to [6], which is a stretched film. [8] A film laminate comprising the polyamide film according to [6] or [7]. [9] The film laminate according to [8], which is for food packaging.

[10] A pellet mixture comprising: first pellets containing a first polyamide resin (A1), an ethylene / α-olefin copolymer (B), and a metal salt of an ethylene / methacrylic acid copolymer (C); and second pellets containing a second polyamide resin (A2), The first pellets contain 69.4 to 97.4 mass% of a first polyamide resin (A1), 1.0 to 20.0 mass% of an ethylene / α-olefin copolymer (B), and 1.0 to 20.0 mass% of a metal salt of an ethylene / methacrylic acid copolymer (C), based on 100 mass% of the first pellets; A pellet mixture comprising, based on 100 mass% of a kneaded product obtained by melt-kneading the pellet mixture, 86.4 to 99.2 mass% in total of a first polyamide resin (A1) and a second polyamide resin (A2), 0.1 to 10.0 mass% of an ethylene / α-olefin copolymer (B), and 0.1 to 10.0 mass% of a metal salt of an ethylene / methacrylic acid copolymer (C).

[11] A method for producing the polyamide resin composition according to any one of [1] to [5], comprising melt-kneading the pellet mixture according to

[10] .

[12] A method for producing a polyamide film according to [6] or [7], comprising melt-kneading the pellet mixture according to

[10] to form a film.

[13] A method for producing the film laminate according to [8] or [9], comprising melt-kneading the pellet mixture according to

[10] to form a polyamide film. Effect of the Invention

[0010] According to the present invention, there can be provided a polyamide resin composition that gives a film that is free from deterioration of appearance due to film gel and has excellent pinhole resistance in a low-temperature environment, and a film and a film laminate using the same. Furthermore, there can be provided a pellet mixture that is suitably used for producing the polyamide resin composition, the film, and the film laminate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In this specification, the content of each component in the composition means the total amount of the multiple substances when the composition contains multiple substances corresponding to each component, unless otherwise specified. In this specification, the term polyamide resin composition means a composition containing at least a polyamide resin, and includes any form such as pellets, sheets, strands, chips, and molded products molded by various methods. The term pellets means one of the forms that the polyamide resin composition can take. The polyamide resin composition and pellets according to the present invention will be described in detail below.

[0012] The polyamide resin composition of the present invention contains, based on 100 mass% of the polyamide resin composition, 86.4 to 99.2 mass% of polyamide resin (A), 0.1 to 10.0 mass% of ethylene / α-olefin copolymer (B), and 0.1 to 10.0 mass% of metal salt of ethylene / methacrylic acid copolymer (C). By setting the contents of the ethylene / α-olefin copolymer (B) and the metal salt of ethylene / methacrylic acid copolymer (C) within the above ranges, a polyamide resin composition can be obtained that gives a film that is free from deterioration of appearance due to film gel and has excellent pinhole resistance in a low temperature environment.

[0013] [Polyamide resin composition] <Polyamide resin (A)> The polyamide resin (A) is not particularly limited, and examples thereof include homopolymers of aliphatic polyamides, copolymers using several kinds of raw material monomers that form these, etc. Examples of raw material monomers that form aliphatic polyamides include lactams, aminocarboxylic acids that are hydrolyzates of lactams, and combinations of aliphatic diamines and aliphatic dicarboxylic acids.

[0014] Specific examples of homopolymers of aliphatic polyamides and copolymers using several kinds of raw monomers that form these include polycaproamide (polyamide 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 succinamide (polyamide 50), polytetramethylene succinamide (polyamide 51), polytetramethylene succinamide (polyamide 52), polytetramethylene succinamide (polyamide 53), polytetramethylene succinamide (polyamide 54), polytetramethylene succinamide (polyamide 55), polytetramethylene succinamide (polyamide 56), polytetramethylene succinamide (polyamide 57), polytetramethylene succinamide (polyamide 58), polytetramethylene succinamide (polyamide 59), polytetramethylene succinamide (polyamide 60), polytetramethylene succinamide (polyamide 61), polytetramethylene succinamide (polyamide 62), polytetramethylene succinamide (polyamide 63), polytetramethylene succinamide (polyamide 64), polytetramethylene succinamide (polyamide 65), polytetramethylene succinamide (polyamide 66), polytetramethylene succinamide (polyamide 67), polytetramethylene succinamide (polyamide 68), polytetramethylene succinamide (polyamide 69), polytetramethylene succinamide (polyamide 70), polytetramethylene succinamide (polyamide 71), polytetramethylene succinamide (polyamide 72), polytetramethylene succinamide (polyamide 73), polytetramethylene succinamide (polyamide 74), polytetramethylene succinamide (polyamide 75), polytetramethylene 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 dodecamide (polyamide 512), polyhexamethylene succinamide (polyamide 6 4), 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 hexadecamide (polyamide 616), polyhexamethylene octadecamide (polyamide 618), polynonamethylene adipamide (polya amide 96), polynonamethylene suberamide (polyamide 98), polynonamethylene azelamide (polyamide 99), polynonamethylene sebacamide (polyamide 910), polynonamethylene dodecamide (polyamide 912), polydecamethylene adipamide (polyamide 106), polydecamethylene suberamide (polyamide 108), polydecamethylene azelamide (polyamide 109), polydecamethylene sebacamide (polyamide 1010), polydecamethylene dodecamide (polyamide 1012), polydodecamethylene adipamide (polyamide 126),Examples include polydodecamethylene suberamide (polyamide 128), polydodecamethylene azelamide (polyamide 129), polydodecamethylene sebacamide (polyamide 1210), polydodecamethylene dodecamide (polyamide 1212), and copolymers using several of the raw monomers of these polyamides.

[0015] As the polyamide resin other than the aliphatic polyamide, a polyamide resin having an alicyclic group or an aromatic group in the main chain or side chain can be used. Examples of the polyamide resin other than the aliphatic polyamide include polymetaxylylene adipamide (polyamide MXD6), polymetaxylylene suberamide (polyamide MXD8), polymetaxylylene azelamide (polyamide MXD9), polymetaxylylene sebacamide (polyamide MXD10), polymetaxylylene dodecamide (polyamide MXD12), polymetaxylylene terephthalamide (polyamide MXDT), polymetaxylylene isophthalamide (polyamide MXDI), polymetaxylylene heptamide (polyamide MXD3), polymetaxylylene terephthalamide (polyamide MXDT), polymetaxylylene isophthalamide (polyamide MXDI), polymetaxylylene heptamide (polyamide MXD4), polymetaxylylene terephthalamide (polyamide MXD5), ​​polymetaxylylene terephthalamide (polyamide MXD6), polymetaxylylene terephthalamide (polyamide MXD7), polymetaxylylene terephthalamide (polyamide MXD8), polymetaxylylene terephthalamide (polyamide MXD9), polymetaxylylene terephthalamide (polyamide MXD10 ... xahydroterephthalamide (Polyamide MXDT(H)), polymetaxylylenenaphthalamide (Polyamide MXDN), polyparaxylyleneadipamide (Polyamide PXD6), polyparaxylylenesuberamide (Polyamide PXD8), polyparaxylyleneazelamid (Polyamide PXD9), polyparaxylylenesebacamide (Polyamide PXD10), polyparaxylylenedodecamide (Polyamide PXD12), polyparaxylyleneterephthalamide (Polyamide PXDT), polyparaxylyleneisophthalamide Poly(2,6-naphthalenedimethylene adipamide) (Polyamide 2,6-BAN6), ... Poly(2,6-naphthalenedimethylene terephthalamide) (Polyamide 2,6-BAN8), Poly(2,6-naphthalenedimethylene azelamide) (Polyamide 2,6-BAN9), Poly(2,6-naphthalenedimethylene sebacamide) (Polyamide 2,6-BAN10), Poly(2,6-naphthalenedimethylene dodecamide) (Polyamide 2,6-BAN12), Poly(2,6-naphthalenedimethylene terephthalamide) (Polyamide 2,6-BANT), Poly(2,6-naphthalenedimethylene isophthalamide) (Polyamide 2,6-BANI),Poly(2,6-naphthalenedimethylenehexahydroterephthalamide) (Polyamide 2,6-BANT(H)), Poly(2,6-naphthalenedimethylenenaphthalamide) (Polyamide 2,6-BANN), Poly(1,3-cyclohexanedimethyleneadipamide) (Polyamide 1,3-BAC6), Poly(1,3-cyclohexanedimethylenesuberamide) (Polyamide 1,3-BAC8), Poly(1,3-cyclohexanedimethyleneazelamide) (Polyamide 1,3-BAC9), Poly(1,3-cyclohexanedimethylenesebacamide) (Polyamide 1,3 -BAC10), poly(1,3-cyclohexanedimethylene dodecamide) (polyamide 1,3-BAC12), poly(1,3-cyclohexanedimethylene terephthalamide) (polyamide 1,3-BACT), poly(1,3-cyclohexanedimethylene isophthalamide) (polyamide 1,3-BACI), poly(1,3-cyclohexanedimethylene hexahydroterephthalamide) (polyamide 1,3-BACT(H)), poly(1,3-cyclohexanedimethylene naphthalamide) (polyamide 1,3-BACN), poly(1,4-cyclohexanedimethylene Poly(1,4-cyclohexanedimethylene adipamide) (Polyamide 1,4-BAC6), Poly(1,4-cyclohexanedimethylene suberamide) (Polyamide 1,4-BAC8), Poly(1,4-cyclohexanedimethylene azelamide) (Polyamide 1,4-BAC9), Poly(1,4-cyclohexanedimethylene sebacamide) (Polyamide 1,4-BAC10), Poly(1,4-cyclohexanedimethylene dodecamide) (Polyamide 1,4-BAC12), Poly(1,4-cyclohexanedimethylene terephthalamide) (Polyamide 1,4-BACT), Poly(1,4-cyclohexa Poly(1,4-dimethylene isophthalamide) (Polyamide 1,4-BACI), poly(1,4-cyclohexanedimethylene hexahydroterephthalamide) (Polyamide 1,4-BACT(H)), poly(1,4-cyclohexanedimethylene naphthalamide) (Polyamide 1,4-BACN), poly(4,4'-methylenebiscyclohexylene adipamide) (Polyamide PACM6), poly(4,4'-methylenebiscyclohexylene suberamide) (Polyamide PACM8), poly(4,4'-methylenebiscyclohexylene azelamide) (Polyamide PACM9),Poly(4,4'-methylenebiscyclohexylenesebacamide) (Polyamide PACM10), Poly(4,4'-methylenebiscyclohexylenedodecamide) (Polyamide PACM12), Poly(4,4'-methylenebiscyclohexylenetetradecamide) (Polyamide PACM14), Poly(4,4'-methylenebiscyclohexylenehexadecamide) (Polyamide PACM16), Poly(4,4'-methylenebiscyclohexyleneoctadecamide) (Polyamide PACM18), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM19), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM20), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM21), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM22), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM23), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM24), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM25), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM26), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM27), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM28), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM29), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM30), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM31), Poly(4,4'-methylenebiscyclohexyleneterecamide) (Polyamide PACM3 phthalamide) (Polyamide PACMT), poly(4,4'-methylenebiscyclohexyleneisophthalamide) (Polyamide PACMI), poly(4,4'-methylenebiscyclohexylenehexahydroterephthalamide) (Polyamide PACMT(H)), poly(4,4'-methylenebiscyclohexylenenaphthalamide) (Polyamide PACMN), poly(4,4'-methylenebis(2-methyl-cyclohexylene)adipamide) (Polyamide MACM6), poly(4,4'-methylenebis(2-methyl-cyclohexylene)suberamide ) (Polyamide MACM8), poly(4,4'-methylenebis(2-methyl-cyclohexylene)azelamide) (Polyamide MACM9), poly(4,4'-methylenebis(2-methyl-cyclohexylene)sebacamide) (Polyamide MACM10), poly(4,4'-methylenebis(2-methyl-cyclohexylene)dodecamide) (Polyamide MACM12), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM14), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM15), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM16), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM17), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM18), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM19), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM20), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM21), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM22), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM23), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM24), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetradecamide) (Polyamide MACM25), poly(4,4'-methylenebis(2-methyl-cyclohexylene)tetra poly(4,4'-methylenebis(2-methyl-cyclohexylene)hexadecaamide) (polyamide MACM16), poly(4,4'-methylenebis(2-methyl-cyclohexylene)octadecaamide) (polyamide MACM18), poly(4,4'-methylenebis(2-methyl-cyclohexylene)terephthalamide) (polyamide MACMT), poly(4,4'-methylenebis(2-methyl-cyclohexylene)isophthalamide) (polyamide MACMI), poly(4,4'-methylenebis(2-methyl-cyclohexylene)hexahydroterephthalamide) (polyamide MACMT(H)),Poly(4,4'-methylenebis(2-methylcyclohexylene)naphthalamide) (Polyamide MACMN), poly(4,4'-propylenebiscyclohexyleneadipamide) (Polyamide PACP6), poly(4,4'-propylenebiscyclohexylenesuberamide) (Polyamide PACP8), poly(4,4'-propylenebiscyclohexyleneazelamide) (Polyamide PACP9), poly(4,4'-propylenebiscyclohexylenesebacamide) (Polyamide PACP10), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP11), poly(4,4'-propylenebiscyclohexylenesebacamide) (Polyamide PACP12), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP13), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP14), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP15), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP16), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP17), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP18), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP19), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP20), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP21), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP22), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP23), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Polyamide PACP24), poly(4,4'-propylenebiscyclohexylenedodecylamide) (Poly camide) (Polyamide PACP12), poly(4,4'-propylene biscyclohexylene tetradecamide) (Polyamide PACP14), poly(4,4'-propylene biscyclohexylene hexadecamide) (Polyamide PACP16), poly(4,4'-propylene biscyclohexylene octadecamide) (Polyamide PACP18), poly(4,4'-propylene biscyclohexylene terephthalamide) (Polyamide PACPT), poly(4,4'-propylene biscyclohexylene isophthalamide) (Polyamide PACPI), poly(4 ,4'-propylenebiscyclohexylenehexahydroterephthalamide) (polyamide PACPT(H)), poly(4,4'-propylenebiscyclohexylenenaphthalamide) (polyamide PACPN), polyisophorone adipamide (polyamide IPD6), polyisophorone peramide (polyamide IPD8), polyisophorone azelamide (polyamide IPD9), polyisophorone sebacamide (polyamide IPD10), polyisophorone indodecamide (polyamide IPD12), polyisophorone terephthalamide (polyamide IPDT), polyisophorone Polyisophorone isophthalamide (Polyamide IPDI), Polyisophorone hexahydroterephthalamide (Polyamide IPDT(H)), Polyisophorone naphthalamide (Polyamide IPDN), Polytetramethylene terephthalamide (Polyamide 4T), Polytetramethylene isophthalamide (Polyamide 4I), Polytetramethylene hexahydroterephthalamide (Polyamide 4T(H)), Polytetramethylene naphthalamide (Polyamide 4N), Polypentamethylene terephthalamide (Polyamide 5T), Polypentamethylene isophthalamide (Polyamide 5I),Polypentamethylene hexahydroterephthalamide (Polyamide 5T(H)), Polypentamethylene naphthalamide (Polyamide 5N), Polyhexamethylene terephthalamide (Polyamide 6T), Polyhexamethylene isophthalamide (Polyamide 6I), Polyhexamethylene hexahydroterephthalamide (Polyamide 6T(H)), Polyhexamethylene naphthalamide (Polyamide 6N), Poly(2-methylpentamethylene terephthalamide) (Polyamide M5T), Poly(2-methylpentamethylene isophthalamide) (Polyamide M5I), Poly(2-methyl pentamethylene hexahydroterephthalamide) (Polyamide M5T(H)), poly(2-methylpentamethylene naphthalamide (Polyamide M5N), polynonamethylene terephthalamide (Polyamide 9T), polynonamethylene isophthalamide (Polyamide 9I), polynonamethylene hexahydroterephthalamide (Polyamide 9T(H)), polynonamethylene naphthalamide (Polyamide 9N), poly(2-methyloctamethylene terephthalamide) (Polyamide M8T), poly(2-methyloctamethylene isophthalamide) (Polyamide M8I), poly(2- Poly(methyloctamethylene hexahydroterephthalamide) (Polyamide M8T(H)), Poly(2-methyloctamethylene naphthalamide) (Polyamide M8N), Polytrimethylhexamethylene terephthalamide (Polyamide TMHT), Polytrimethylhexamethylene isophthalamide (Polyamide TMHI), Polytrimethylhexamethylene hexahydroterephthalamide (Polyamide TMHT(H)), Polytrimethylhexamethylene naphthalamide (Polyamide TMHN), Polydecamethylene terephthalamide (Polyamide 10T), Polydecamethylene isof thalamide (polyamide 10I), polydecamethylene hexahydroterephthalamide (polyamide 10T(H)), polydecamethylene naphthalamide (polyamide 10N), polyundecamethylene terephthalamide (polyamide 11T), polyundecamethylene isophthalamide (polyamide 11I), polyundecamethylene hexahydroterephthalamide (polyamide 11T(H)), polyundecamethylene naphthalamide (polyamide 11N), polydodecamethylene terephthalamide (polyamide 12T), polydodecamethylene isophthalamide (polyamide 12I),Examples of the polyamide include polydodecamethylene hexahydroterephthalamide (polyamide 12T(H)), polydodecamethylene naphthalamide (polyamide 12N), and copolymers using several kinds of raw monomers of these polyamides.

[0016] The polyamide resin (A) may be one type or a combination of two or more types.

[0017] Among polyamide resins, from the viewpoints of the heat resistance, mechanical strength and transparency of the obtained molded article, economic efficiency, ease of availability, and the like, at least one selected from the group consisting of polycaproamide (polyamide 6), polyundecaneamide (polyamide 11), polydodecanamide (polyamide 12), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polydecamethylene sebacamide (polyamide 1010), polydecamethylene dodecamide (polyamide 1012), and polydodecamethylene dodecamide (polyamide 1212) is preferred. It is preferable to use at least one type of homopolymer and / or a copolymer using several types of raw material monomers that form the homopolymer, and it is more preferable to use at least one type selected from the group consisting of polyamide 6, a copolymer of polyamide 6 and polyamide 66 (polyamide 6 / 66), a copolymer of polyamide 6 and polyamide 12 (polyamide 6 / 12), and a copolymer of polyamide 6, polyamide 66 and polyamide 12 (polyamide 6 / 66 / 12), and it is particularly preferable to use at least one type selected from the group consisting of polyamide 6, and a copolymer of polyamide 6 and polyamide 66 (polyamide 6 / 66).

[0018] From the viewpoint of moldability, the relative viscosity of the polyamide resin (A) is preferably 2.0 to 4.5, more preferably 2.0 to 4.2, and even more preferably 2.5 to 4.0. If the relative viscosity of the polyamide resin (A) is less than 2.0, the mechanical strength of the resulting polyamide film is likely to be low. If it is more than 4.5, the viscosity during melting is high, making it difficult to mold the film.

[0019] The relative viscosity of polyamide resin (A) is a value measured at 25° C. by dissolving 1 g of polyamide resin (A) in 100 ml of 96% sulfuric acid in accordance with JIS K 6920. When polyamide resin (A) is a combination of two or more types, it is preferable to measure the relative viscosity by the above method, but when the relative viscosity of each polyamide resin and its mixing ratio are known, the relative viscosity of polyamide resin (A) may be calculated by multiplying each relative viscosity by the mixing ratio and adding up the values, and the average value calculated may be used as the relative viscosity of polyamide resin (A).

[0020] The content of the polyamide resin (A) is 86.4 to 99.2% by mass in 100% by mass of the polyamide resin composition. By setting the content of the polyamide resin (A) in the above range, the polyamide resin (A) exhibits good compatibility with the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C), and the melt stability of the polyamide resin composition and the moldability of the film are improved. Furthermore, the deterioration of the appearance of the polyamide film molded from the polyamide resin composition due to film gel can be suppressed, and the transparency and good pinhole resistance of the film can be maintained. The content of the polyamide resin (A) is preferably 93.0% by mass or more, more preferably 96.0% by mass or more, and particularly preferably 97.0% by mass or more in 100% by mass of the polyamide resin composition. The content of the polyamide resin (A) is preferably 99.0% by mass or less, more preferably 98.0% by mass or less in 100% by mass of the polyamide resin composition.

[0021] The polyamide resin production apparatus may be a known polyamide production apparatus such as a batch reaction vessel, a single- or multi-vessel continuous reaction apparatus, a tubular continuous reaction apparatus, a kneading reaction extruder such as a single-screw kneading extruder or a twin-screw kneading extruder. The polymerization method may be a known method such as melt polymerization, solution polymerization, or solid-phase polymerization, and may be carried out by repeating normal pressure, reduced pressure, and increased pressure operations. These polymerization methods may be used alone or in appropriate combination.

[0022] <Ethylene / α-olefin copolymer (B)> The polyamide resin composition contains an ethylene / α-olefin copolymer (B). By containing the ethylene / α-olefin copolymer (B), the pinhole resistance of a film molded from the polyamide resin composition in a low-temperature environment can be improved.

[0023] The ethylene / α-olefin copolymer (B) is a comonomer of ethylene and an α-olefin having 3 or more carbon atoms. The carbon number of the α-olefin is preferably 3 to 20, and more preferably 3 to 10. The molecular structure of the ethylene / α-olefin copolymer (B) may be linear or branched having a long or short side chain. The ethylene / α-olefin copolymer (B) may be one type or a combination of two or more types.

[0024] Specific examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene. These may be used alone or in combination of two or more. Among them, from the viewpoint of imparting good flexibility to the polyamide resin composition, propylene, 1-butene, 1-hexene and 1-octene are preferred, and 1-butene is particularly preferred.

[0025] The ethylene / α-olefin copolymer (B) may be one which is copolymerized with, for example, a non-conjugated diene such as 1,6-hexadiene or 1,8-octadiene, or a cyclic olefin such as cyclopentene, as long as it does not impede the object of the present invention.

[0026] From the viewpoint of ensuring desirable moldability by controlling the viscosity during melting in an appropriate range, preventing excessive reduction in melt tension, and preventing problems such as drawdown during molding, the ethylene / α-olefin copolymer (B) preferably has a melt flow rate measured at 190°C and a load of 2.16 kg of 0.1 g / 10 min to 10 g / 10 min, more preferably 0.5 g / 10 min to 7 g / 10 min, and particularly preferably 1 g / 10 min to 5 g / 10 min. The ethylene / α-olefin copolymer (B) also preferably has a density of 850 kg / m 2 measured according to ASTM D1505. 3 More than 900kg / m 3 It is desirable that the following:

[0027] The ethylene / α-olefin copolymer (B) may contain a comonomer such as an unsaturated carboxylic acid or a salt or ester thereof as a copolymerization component, as long as the object of the present invention is not impaired. However, it is preferable that the copolymerization component is not contained.

[0028] The content of the ethylene / α-olefin copolymer (B) is 0.1 to 10.0% by mass in 100% by mass of the polyamide resin composition. By setting the content of the ethylene / α-olefin copolymer (B) in the above range, the polyamide resin (A) exhibits good compatibility with the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C), and the melt stability of the polyamide resin composition and the moldability of the film are improved. Furthermore, the deterioration of the appearance of the polyamide film molded from the polyamide resin composition due to film gel can be suppressed, the transparency of the film can be maintained, and the pinhole resistance in a low-temperature environment can be improved. The content of the ethylene / α-olefin copolymer (B) is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 1.6% by mass or more in 100% by mass of the polyamide resin composition. In addition, from the viewpoints of reducing film gel and transparency of the film, the content of the ethylene / α-olefin copolymer (B) is preferably 6.0 mass% or less, more preferably 3.0 mass% or less, even more preferably 2.2 mass% or less, and particularly preferably 2.0 mass% or less, based on 100 mass% of the polyamide resin composition. If the content of the ethylene / α-olefin copolymer (B) in 100% by mass of the polyamide resin composition is less than 0.1% by mass, the pinhole resistance of the molded film in a low-temperature environment does not improve. If it exceeds 10.0% by mass, the dispersibility of the ethylene / α-olefin copolymer (B) in the polyamide resin composition deteriorates, the film gel increases, and the transparency of the film deteriorates.

[0029] <Metal salt of ethylene / methacrylic acid copolymer (C)> The polyamide resin composition contains a metal salt of an ethylene / methacrylic acid copolymer (C). The metal salt of an ethylene / methacrylic acid copolymer (C) refers to a copolymer of ethylene and methacrylic acid and / or a methacrylic acid ester neutralized with a metal or a metal ion. By including the metal salt of an ethylene / methacrylic acid copolymer (C), the dispersibility of the ethylene / α-olefin copolymer (B) in the polyamide resin composition can be improved, and the pinhole resistance of a film molded from the polyamide resin composition in a low-temperature environment can be improved. The metal salt of an ethylene / methacrylic acid copolymer (C) may be one type or a combination of two or more types.

[0030] The ethylene / methacrylic acid copolymer used in the metal salt of ethylene / methacrylic acid copolymer (C) is not particularly limited as long as it is made of ethylene and methacrylic acid and / or methacrylic acid ester as raw materials, and may further use other raw materials. That is, the ethylene / methacrylic acid copolymer may have units other than ethylene units and methacrylic acid units (units of methacrylic acid and methacrylic acid ester). For example, an ethylene / methacrylic acid / acrylic acid ester copolymer may be used as the ethylene / methacrylic acid copolymer.

[0031] In the ethylene / methacrylic acid copolymer, from the viewpoint of compatibility with the polyamide resin (A), the content of ethylene units is preferably 10 to 90 mol %, more preferably 20 to 80 mol %, and the content of methacrylic acid units is preferably 10 to 90 mol %, more preferably 20 to 80 mol %.

[0032] The metal salt of ethylene / methacrylic acid copolymer (C) may contain multiple types of metal salts of ethylene / methacrylic acid copolymers with different ethylene unit contents. In this case, the ethylene unit content in the metal salt of ethylene / methacrylic acid copolymer (C) can be determined by the sum of the product of the ethylene content in each hydrolyzate of the metal salt of ethylene / methacrylic acid copolymer and the mixing molar ratio of ethylene in each hydrolyzate. The ethylene unit content in the metal salt of ethylene / methacrylic acid copolymer (C) can be determined by nuclear magnetic resonance (NMR).

[0033] Examples of metals and metal ions used in the metal salt (C) of an ethylene / methacrylic acid copolymer include Na, K, Cu, Mg, Ca, Ba, Zn, Cd, Al, Fe, Co, and Ni, as well as ions thereof. These may be used alone or in combination of two or more, but it is preferable to use at least Zn (also referred to as "zinc" in this specification).

[0034] The metal salt of ethylene / methacrylic acid copolymer (C) is preferably at least one of partial zinc salt of ethylene / methacrylic acid copolymer and partial zinc salt of ethylene / methacrylic acid / acrylic acid ester copolymer from the viewpoint of improving pinhole resistance and impact resistance at low temperatures, and more preferably partial zinc salt of ethylene / methacrylic acid copolymer from the viewpoint of improving compatibility with polyamide resin (A). An example of partial zinc salt of ethylene / methacrylic acid copolymer is Himilan (registered trademark) 1706 manufactured by Dow Mitsui Polychemical Co., Ltd. An example of partial zinc salt of ethylene / methacrylic acid / acrylic acid ester copolymer is Himilan (registered trademark) 1855 manufactured by Dow Mitsui Polychemical Co., Ltd.

[0035] The melt flow rate (MFR) of the metal salt of ethylene / methacrylic acid copolymer (C) at 190°C under a load of 2160 g is preferably 0.5 g / 10 min or more and 3.0 g / 10 min or less, more preferably 0.5 g / 10 min or more and 2.0 g / 10 min or less, and even more preferably 0.5 g / 10 min or more and 1.5 g / 10 min or less, from the viewpoints of keeping the viscosity during melting in an appropriate range to ensure desirable moldability, not excessively reducing the melt tension, and preventing problems such as drawdown during molding.

[0036] The content of the metal salt (C) of the ethylene / methacrylic acid copolymer is 0.1 to 10.0% by mass in 100% by mass of the polyamide resin composition. By setting the content of the metal salt (C) of the ethylene / methacrylic acid copolymer in the above range, the pinhole resistance of the film molded from the polyamide resin composition in a low-temperature environment can be improved. The content of the metal salt (C) of the ethylene / methacrylic acid copolymer is preferably 0.10% by mass or more in 100% by mass of the polyamide resin composition, more preferably 0.15% by mass or more, even more preferably 0.4% by mass or more, and particularly preferably 0.5% by mass or more. In addition, from the viewpoint of the moldability of the film, the content of the metal salt (C) of the ethylene / methacrylic acid copolymer is 10.0% by mass or less, preferably 8.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less in 100% by mass of the polyamide resin composition. In addition, from the viewpoints of reducing film gel and transparency of the film, the content of the metal salt of ethylene / methacrylic acid copolymer (C) is preferably 1.0 mass% or less, more preferably 0.9 mass% or less, even more preferably 0.8 mass% or less, even more preferably 0.7 mass% or less, and particularly preferably 0.6 mass% or less, based on 100 mass% of the polyamide resin composition. Furthermore, the metal ion neutralization degree of the metal salt (C) of ethylene / methacrylic acid copolymer is preferably in the range of 20 to 80%, more preferably in the range of 50 to 70%. By setting the metal ion neutralization degree within the above range, the transparency of the polyamide film can be maintained. The metal ion neutralization degree of the metal salt (C) of ethylene / methacrylic acid copolymer is defined by the following formula: Degree of neutralization (%) of metal ions in metal salts of ethylene / methacrylic acid copolymers (C) = 100 × {(number of moles of neutralized carboxyl groups in the metal salt (C) of ethylene / methacrylic acid copolymer) / (total number of moles of carboxyl groups in the metal salt (C) of ethylene / methacrylic acid copolymer)} If the content of the metal salt (C) of an ethylene / methacrylic acid copolymer in 100% by mass of the polyamide resin composition is less than 0.1% by mass, the pinhole resistance of the molded film in a low-temperature environment is not improved. If it exceeds 10.0% by mass, the moldability and transparency of the film are deteriorated, and further, the film gel increases.

[0037] The total content of the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C) in the polyamide resin composition is 0.2% by mass or more, preferably 1.0% by mass or more, and more preferably 2.0% by mass in 100% by mass of the polyamide resin composition from the viewpoint of pinhole resistance in a low-temperature environment of the molded film. The total content of the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C) in the polyamide resin composition is 13.0% by mass or less, and more preferably 3.4% by mass or less, from the viewpoint of film gel reduction and transparency of the polyamide film, from the viewpoint of dispersibility of each component in the polyamide resin composition.

[0038] The mass ratio (C / B) of the metal salt of ethylene / methacrylic acid copolymer (C) to the ethylene / α-olefin copolymer (B) is preferably 0.04 to 0.60, more preferably 0.08 to 0.50, and particularly preferably 0.10 to 0.40. By setting it within the above range, the dispersibility of each component in the polyamide resin is improved, and the production stability of pellets and the moldability of films tend to be improved.

[0039] <Other ingredients (D)> The polyamide resin composition may contain another component (D) other than the components (A) to (C). Examples of the other components include thermoplastic resins other than the components (A) to (C), antioxidants, antiblocking agents, lubricants, nucleating agents, plasticizers, foaming agents, stabilizers, UV absorbers, weather resistance agents, antifogging agents, colorants, etc. Among these, it is preferable that the polyamide resin composition contains an antioxidant and / or an antiblocking agent.

[0040] The content of the other component (D) is preferably 10.0 mass% or less, more preferably 8.0 mass% or less, even more preferably 6.0 mass% or less, and particularly preferably 4.0 mass% or less, based on 100 mass% of the polyamide resin composition. The content of the other component (D) is preferably 0.01 mass% or more, more preferably 0.04 mass% or more, and even more preferably 0.06 mass% or more, based on 100 mass% of the polyamide resin composition.

[0041] (Antioxidants) From the viewpoint of further reducing the amount of film gel generation, the polyamide resin composition preferably contains an antioxidant. The antioxidant may be one type or a combination of two or more types. The antioxidant is preferably at least one type selected from the group consisting of phenol-based compounds, phosphorus-based compounds, and sulfur-based compounds. The phenolic compound is preferably a hindered phenolic compound. Examples of the phenolic compound include pentaerythritol-tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate], 2,6-di-t-butylphenol, 2,4-dimethyl-6-t-butylphenol, butylhydroxytoluene (BHT), 2,6-di-t-butyl-4-ethyl-phenol, 2,4,6-tri-t-butylphenol, 2,6-di-t-butyl-4-s-butylphenol, butylhydroxyanisole (BHA), tocopherol, 2,6-di-t-butyl-4-hydroxymethylphenol, n-octadecyl-β-(4'-hydroxy3'5'-di -t-butylphenyl)propionate, 2-t-butyl-4-(N,N-dimethylaminomethyl)phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, propyl gallate, octyl gallate, lauryl gallate, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-methylenebis(2,6-di-t-butylphenol), 2,2'-methylenebis(4-methyl 2,2'-Dihydroxy-3,3'-di(α-methylcyclohexyl)-5,5'-dimethyldiphenylmethane, 2,2'-Dimethylen-bis-(6-α-methyl-benzyl-p-cresol), 2,2'-Ethylidene-bis(4,6-di-t-butylphenol), 2,2'-Butylidene-bis(4-methyl-6-t-butylphenol), 4,4'-Butylidenebis(3-methyl-6-t-butylphenol), Triethylene glycol-N-bis-3-( 3-t-butyl-4-hydroxy-5-methylphenyl)propionate, 1,6-hexanediol bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, bis[2-t-butyl-4-methyl-6-(3-t-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]Undecane, 4,4'-thiobis(6-t-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 2,2'-thiobis(4-methyl-6-t-butylphenol), bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide, 4,4'-di- and tri-thiobis(2,6-di-t-butylphenol), 2,2-thiodiethylenebis-[3(3,5-di-t-butyl-4-hydroxy phenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy3',5'-di-t-butylanilino)-1,3,5-triazine, N,N'-hexamethylenebis-(3,5-di-t-butyl-4-hydroxyhydrocinnamide, N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine, calcium (3,5-di-t-butyl-4-hydroxybenzyl monoethyl phosphatide) sphonates), alkylated bisphenols, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-t-butyl-4-hydroxyphenyl)isocyanurate, tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4- t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris-2[3(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanate, tetrakis[methylene-3-(3',5'-di-t-butyl-4-hydroxyphenyl)propionate]methane, butyric acid, 3,3-bis(3-t-butyl-4-hydroxyphenyl)ethylene ester, etc. can be mentioned.

[0042] Examples of phosphorus compounds include triphenyl phosphite, diphenyl nonylphenyl phosphite, tris-(2,4-di-t-butylphenyl) phosphite, tris-nonylphenyl phosphite, tris-(mixed mono and di nonylphenyl) phosphite, diphenyl isooctyl phosphite, 2,2'-methylenebis(4,6-di-t-butylphenyl) octyl phosphite, diphenyl isodecyl phosphite, diphenyl mono(tridecyl) phosphite, 2,2'-ethylidene bis(4,6 -di-t-butylphenol)fluorophosphite, phenyl diisodecyl phosphite, phenyl di(tridecyl)phosphite, tris(2-ethylhexyl)phosphite, tris(isodecyl)phosphite, tris(tridecyl)phosphite, dibutyl hydrogen phosphite, trilauryl trithiophosphite, tetrakis(2,4-di-t-butylphenyl)4,4'-biphenylene diphosphonite, 4,4'-isopropylidenediphenol alkyl(C12-C15)phosphite phosphite, 4,4'-butylidenebis(3-methyl-6-t-butylphenyl)di-tridecylphosphite, distearyl-pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, cyclic neopentanetetraylbis(2,6-di-t-butyl-4-methylphenyl phosphite, phenyl-bisphenol A pentaerythritol diphosphite, tetraphenyl dipropionate Examples of suitable phosphate esters include ethylene glycol diphosphite, 1,1,3-tris(2-methyl-4-di-tridecylphosphite-5-t-butylphenyl)butane, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, zinc dialkyldithiophosphate (ZnDTP), 3,4,5,6-dibenzo-1,2-oxaphosphane-2-oxide, 3,5-di-t-butyl-4-hydroxybenzylphosphite-diethyl ester, and hydrogenated bisphenol A phosphite polymers.

[0043] Examples of sulfur compounds include dilauryl-3,3'-thiodipropionate (DLTTDP), ditridecyl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate (DMTDP), distearyl-3,3'-thiodipropionate (DSTDP), laurylstearyl-3,3'-thiodipropionate, pentaerythritol tetra(β-lauryl-thiopropionate) ester, stearylthiopropionamide, bis[2-methyl-4-(3-n-alkyl(C12-C14)thiopropionyloxy)-5-t-butylphenyl]sulfide, dioctadecyl disulfide, 2-mercaptobenzimidazole, 2-mercapto-6-methylbenzimidazole, and 1,1'-thiobis(2-naphthol).

[0044] As other antioxidants, organic antioxidants other than phenolic compounds, phosphorus compounds and sulfur compounds, and inorganic antioxidants such as metal halide compounds may be used. Examples of metal halide compounds include cuprous iodide, potassium iodide, cuprous bromide, potassium bromide, etc.

[0045] Examples of commercially available antioxidants that are preferably used include Irganox (registered trademark) 1010, Irganox (registered trademark) 1098, Irgafos 168, Irganox (registered trademark) B220, Irganox (registered trademark) B225 (all manufactured by BASF Japan Ltd.), Sumilizer (registered trademark) GP, Sumilizer (registered trademark) GA-80 (all manufactured by Sumitomo Chemical Co., Ltd.). Among them, from the viewpoint of preventing thermal degradation of the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C), Irganox (registered trademark) 1010, Irganox (registered trademark) 1098, and Irgafos (registered trademark) 168 are preferred.

[0046] From the viewpoint of preventing thermal degradation of the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C), the content of the antioxidant is preferably 0.01% by mass or more, more preferably 0.04% by mass or more, and even more preferably 0.06% by mass or more, based on 100% by mass of the polyamide resin composition. Also, from the viewpoint of preventing bleeding out onto the surface of the molded film, the content of the antioxidant is preferably 0.6% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.4% by mass or less, based on 100% by mass of the polyamide resin composition.

[0047] (Anti-blocking agent) The polyamide resin composition preferably contains an antiblocking agent for the purpose of improving the handling properties of the formed film. Examples of the antiblocking agent include minerals such as talc, diatomaceous earth, calcium carbonate, feldspars, and quartz, synthetic silica, and crosslinked resin beads. The antiblocking agent may be one type or a combination of two or more types.

[0048] The content of the antiblocking agent is preferably 0.01 mass% or more, and more preferably 0.04 mass% or more, and is preferably 0.6 mass% or less, and more preferably 0.5 mass% or less, based on 100 mass% of the polyamide resin composition.

[0049] [Method of producing polyamide resin composition] The method for producing the polyamide resin composition is not particularly limited. For example, the following Production Methods 1 and 2 can be applied as the method for producing the polyamide resin composition.

[0050] (Manufacturing method 1) A polyamide resin composition is obtained by melt-kneading the polyamide resin (A), the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C) in a kneader. The polyamide resin composition may contain other components (D). Examples of the kneader include single-screw and twin-screw extruders, Banbury mixers, kneaders, mixing rolls, and the like. For example, any method may be used, such as a method in which all raw materials are blended using a twin-screw extruder and then melt-kneaded, or a method in which a portion of the raw materials is blended and then the remaining raw materials are mixed using a side feeder during melt-kneading. When the polyamide resin composition is melted in a film forming machine or the like and processed into a film, it is preferable to process it into a pellet shape in advance from the viewpoint of the production stability of the film and the dispersibility of each component in the polyamide resin composition.

[0051] (Manufacturing method 2) The first polyamide resin (A1), the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C) are melt-kneaded in advance in a kneader to obtain a melt-kneaded product (E). A second polyamide resin (A2) is prepared separately. The melt-kneaded product (E) and the second polyamide resin (A2) may be mixed with other components (D). The melt-kneaded product (E) and the second polyamide resin (A2) are each formed into pellets, and then these pellets and other components (D) as necessary are uniformly dry-blended to a specific ratio using, for example, a tumbler, a mixer, or the like to obtain a pellet mixture. The pellet mixture can also be melt-kneaded in a kneader to obtain a polyamide resin composition. As the kneader, the one exemplified in the production method 1 can be used. The components (B) and (C) are melt-kneaded with the first polyamide resin (A1) to produce a melt-kneaded product (E), which is then pelletized and dry-blended with pellets of the second polyamide resin (A2) to produce a pellet mixture, which improves the dispersibility of the components (B) and (C) in the polyamide resin composition obtained by melt kneading. The improved dispersibility of the components (B) and (C) is believed to contribute to the improvement of pinhole resistance and the reduction of film gel in a low-temperature environment of the molded film.

[0052] The first polyamide resin (A1) and the second polyamide resin (A2) may be the same or different. The first polyamide resin (A1) and the second polyamide resin (A2) are preferably at least one selected from the group consisting of polyamide 6, polyamide 6 / 66, polyamide 6 / 12, and polyamide 6 / 66 / 12, and more preferably at least one selected from the group consisting of polyamide 6 and polyamide 6 / 66. The first polyamide resin (A1) and the second polyamide resin (A2) may be one type or a combination of two or more types.

[0053] From the viewpoint of pinhole resistance of the molded polyamide film in a low-temperature environment, the content of the melt-kneaded product (E) is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, even more preferably 3.0% by mass or more, and particularly preferably 6.0% by mass or more, based on 100% by mass of the polyamide resin composition. Also, from the viewpoint of dispersibility of each component in the polyamide resin composition, the content of the melt-kneaded product (E) is preferably 20.0% by mass or less, more preferably 16.0% by mass or less, and even more preferably 15.0% by mass or less, based on 100% by mass of the polyamide resin composition.

[0054] [Pellet mixture] When the polyamide resin composition is produced by the above-mentioned production method 2, it is preferable to use a pellet mixture including a first pellet containing a first polyamide resin (A1), an ethylene / α-olefin copolymer (B), and a metal salt of an ethylene / methacrylic acid copolymer (C); and a second pellet containing a second polyamide resin (A2). The second pellet is not the first pellet. That is, the polyamide resin compositions constituting the first pellet and the second pellet are different from each other. The second pellet may contain less than 1.0 mass% of the ethylene / α-olefin copolymer (B) and the metal salt of an ethylene / methacrylic acid copolymer (C) in 100 mass% of the second pellet, but it is preferable that the second pellet does not contain the components (B) and (C). The first pellet and the second pellet may each be one type or a combination of two or more types.

[0055] The first pellets and the second pellets may each contain other components (D) such as an antioxidant, an antiblocking agent, etc. The pellet mixture may contain other components (D) such as an antioxidant, an antiblocking agent, etc. in addition to the first pellets and the second pellets.

[0056] The first polyamide resin (A1) and the second polyamide resin (A2) may be the same as those described in the polyamide resin (A), and the preferred types of resins are also the same. The first polyamide resin (A1) and the second polyamide resin (A2) may be the same or different.

[0057] (First pellet) From the viewpoint of melt stability during melt kneading in the production of the first pellets, the content of the first polyamide resin (A1) is preferably 69.4 mass% or more, more preferably 70.0 mass% or more, and even more preferably 72.0 mass% or more in 100 mass% of the melt kneaded product (E) or the first pellets. Also, from the viewpoint of pinhole resistance, the content of the first polyamide resin (A1) is preferably 97.4 mass% or less, more preferably 90.0 mass% or less, and even more preferably 85.0 mass% or less in 100 mass% of the melt kneaded product (E) or the first pellets.

[0058] From the viewpoint of pinhole resistance, the content of the ethylene / α-olefin copolymer (B) is preferably 1.0% by mass or more, more preferably 10.0% by mass or more, and even more preferably 15.0% by mass or more, based on 100% by mass of the melt-kneaded product (E) or the first pellets. Also, from the viewpoint of film transparency and film gel, the content of the ethylene / α-olefin copolymer (B) is preferably 20.0% by mass or less, more preferably 19.0% by mass or less, and even more preferably 18.0% by mass or less, based on 100% by mass of the melt-kneaded product (E) or the first pellets.

[0059] From the viewpoint of compatibility between the polyamide resin (A1) and the components (B) to (D), the content of the metal salt (C) of the ethylene / methacrylic acid copolymer is preferably 1.0% by mass or more, more preferably 2.0% by mass or more, and even more preferably 3.0% by mass or more, based on 100% by mass of the melt-kneaded product (E) or the first pellets. Also, from the viewpoint of transparency of the film, the content of the metal salt (C) of the ethylene / methacrylic acid copolymer is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, even more preferably 8.0% by mass or less, and particularly preferably 7.0% by mass or less, based on 100% by mass of the melt-kneaded product (E) or the first pellets.

[0060] The content of the other component (D) is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 8.0% by mass or less, based on 100% by mass of the melt-kneaded product (E) or the first pellets. The content of the other component (D) is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, based on 100% by mass of the melt-kneaded product (E) or the first pellets.

[0061] The other component (D) preferably contains an antioxidant and / or an antiblocking agent. The content of the antioxidant is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, and even more preferably 3.5% by mass or less, based on 100% by mass of the melt-kneaded product (E) or the first pellets. The content of the antioxidant is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, based on 100% by mass of the melt-kneaded product (E) or the first pellets.

[0062] From the viewpoint of pinhole resistance, the content of the first pellets is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, even more preferably 3.0% by mass or more, and particularly preferably 6.0% by mass or more, based on 100% by mass of the pellet mixture. Also, from the viewpoint of film transparency and film gel, the content of the first pellets is preferably 20.0% by mass or less, more preferably 16.0% by mass or less, and even more preferably 15.0% by mass or less, based on 100% by mass of the pellet mixture.

[0063] (Second pellet) The second pellets may contain less than 1.0 mass% each of the ethylene / α-olefin copolymer (B) and the metal salt of the ethylene / methacrylic acid copolymer (C) in 100 mass% of the second pellets. In a preferred embodiment, the second pellets do not contain the components (B) and (C).

[0064] The content of the other component (D) is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 8.0% by mass or less, based on 100% by mass of the second pellets. The content of the other component (D) is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, based on 100% by mass of the second pellets.

[0065] The second pellets preferably contain an antioxidant and / or an antiblocking agent as the other component (D).

[0066] From the viewpoint of film transparency, the content of the second pellets is preferably 80.0% by mass or more, more preferably 84.0% by mass or more, and even more preferably 85.0% by mass or more, based on 100% by mass of the pellet mixture. Also, from the viewpoint of pinhole resistance, the content of the second pellets is preferably 99.9% by mass or less, more preferably 99.0% by mass or less, even more preferably 97.0% by mass or less, and particularly preferably 94.0% by mass or less, based on 100% by mass of the pellet mixture.

[0067] (Pellet mixture) From the viewpoints of melt stability during melt kneading, compatibility of the polyamide resin with the (B) to (D) components, and moldability and transparency of the film, the total content of the first polyamide resin (A1) and the second polyamide resin (A2) is preferably 86.4% by mass or more, more preferably 93.0% by mass or more, even more preferably 96.0% by mass or more, and particularly preferably 97.0% by mass or more, in 100% by mass of the kneaded product after melt kneading the pellet mixture. Also, from the viewpoint of pinhole resistance, the total content of the first polyamide resin (A1) and the second polyamide resin (A2) is preferably 99.2% by mass or less, more preferably 99.0% by mass or less, and even more preferably 98.0% by mass or less, in 100% by mass of the kneaded product after melt kneading the pellet mixture.

[0068] From the viewpoint of pinhole resistance of the formed film in a low-temperature environment, the content of the ethylene / α-olefin copolymer (B) is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, even more preferably 1.3% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 1.6% by mass or more, based on 100% by mass of the kneaded product after melt-kneading the pellet mixture. Also, from the viewpoint of film gel reduction and transparency of the film, the content of the ethylene / α-olefin copolymer (B) is preferably 10.0% by mass or less, more preferably 6.0% by mass or less, even more preferably 3.0% by mass or less, even more preferably 2.2% by mass or less, and particularly preferably 2.0% by mass or less, based on 100% by mass of the kneaded product after melt-kneading the pellet mixture.

[0069] From the viewpoint of pinhole resistance of the formed film in a low-temperature environment, the content of the metal salt (C) of the ethylene / methacrylic acid copolymer is preferably 0.1% by mass or more, more preferably 0.10% by mass or more, even more preferably 0.15% by mass or more, even more preferably 0.4% by mass or more, and particularly preferably 0.5% by mass or more, in 100% by mass of the kneaded product after melt-kneading the pellet mixture. Also, from the viewpoint of the moldability of the film, the content of the metal salt (C) of the ethylene / methacrylic acid copolymer is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, even more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less, in 100% by mass of the kneaded product after melt-kneading the pellet mixture. In addition, from the viewpoints of reducing film gel and transparency of the film, the content of the metal salt (C) of the ethylene / methacrylic acid copolymer is preferably 1.0 mass% or less, more preferably 0.9 mass% or less, even more preferably 0.8 mass% or less, even more preferably 0.7 mass% or less, and particularly preferably 0.6 mass% or less, based on 100 mass% of the kneaded product after melt-kneading the pellet mixture.

[0070] The content of the other component (D) is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, even more preferably 6.0% by mass or less, and particularly preferably 4.0% by mass or less, based on 100% by mass of the kneaded product after melt-kneading the pellet mixture. The content of the other component (D) is preferably 0.01% by mass or more, more preferably 0.04% by mass or more, and even more preferably 0.06% by mass or more, based on 100% by mass of the kneaded product after melt-kneading the pellet mixture.

[0071] When the other component (D) contains an antioxidant, the content of the antioxidant is preferably 0.01% by mass or more, more preferably 0.04% by mass or more, and even more preferably 0.06% by mass or more in 100% by mass of the kneaded product after melt-kneading the pellet mixture. From the viewpoint of preventing bleeding out to the surface of the molded film, the content of the antioxidant is preferably 0.6% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.4% by mass or less in 100% by mass of the kneaded product after melt-kneading the pellet mixture.

[0072] (Pellet manufacturing) The pellets can be obtained, for example, by extruding the polyamide resin composition in the form of strands from an extruder or the like, and cutting the strands with a cutter having a rotary blade.

[0073] The pellet shape may be spherical, rectangular, spheroidal, slightly deformed from an exact spheroid, cylindrical with a circular or elliptical cross section, etc. Among these, the pellet shape is preferably spherical, spheroidal, or cylindrical with a circular or elliptical cross section.

[0074] When the pellet has an elliptical cross section, the major axis is preferably 1 to 5 mm, more preferably 2 to 4 mm, and even more preferably 2.0 to 3.5 mm. When the pellet has an elliptical cross section, the minor axis is preferably 1 to 3 mm, and more preferably 2 to 3 mm. The ratio of the major axis to the minor axis (major axis / minor axis) is not particularly limited, but is preferably 1 to 4.

[0075] The major and minor diameters of the pellets can be controlled, for example, by adjusting the diameter of the nozzle of an extruder or the like to change the diameter of the strands.

[0076] The length of the pellet is not particularly limited, but is preferably 2 to 4 mm, and more preferably 2.5 to 4.0 mm.

[0077] [Polyamide film] The polyamide film contains a polyamide resin composition. The polyamide film may be an unstretched polyamide film, or may be a stretched polyamide film obtained by stretching the unstretched polyamide film. From the viewpoint of mechanical strength, the polyamide film is preferably a stretched polyamide film.

[0078] The method for producing the polyamide film is not particularly limited, and for example, a known production method can be applied. For example, the polyamide resin composition obtained by the above-mentioned production method 1 is melt-kneaded using an extruder, extruded into a film shape using a die such as a T-die or a coat hanger die, cast on a casting roll surface, and then cooled to produce a polyamide film. Also, a polyamide film can be produced in a similar manner by melt-kneading the melt-kneaded product (E) or the first pellets, the polyamide resin (A2) or the second pellets, and any other components using an extruder according to the above-mentioned production method 2. Furthermore, a polyamide film can be produced in a similar manner by melt-kneading the pellet mixture using an extruder or the like.

[0079] The produced polyamide film may be stretched to form a stretched film. In this case, the produced polyamide film may be uniaxially stretched to form a uniaxially stretched film, or biaxially stretched (simultaneous biaxial stretching, sequential biaxial stretching) to form a biaxially stretched film. The stretching method is not particularly limited, and examples thereof include uniaxial stretching using a heated roll, simultaneous biaxial stretching using a tubular method, and sequential biaxial stretching using a heated roll and a tenter. The temperature of the heated roll is not particularly limited, and can be in the range of 35°C to 130°C, and can be appropriately selected depending on the material of the polyamide film and the intended stretching ratio. The stretching ratio includes the stretching ratio in the extrusion direction (MD) of the film and the perpendicular direction (TD) to the extrusion direction of the film. The stretching ratio in the extrusion direction of the film is not particularly limited, and is preferably 2 times or more, more preferably 2 to 6 times, and particularly preferably 2.5 to 5 times. The stretching ratio in the perpendicular direction to the extrusion direction of the film is not particularly limited, and is preferably 2 times or more, more preferably 2 to 6 times, and particularly preferably 2.5 to 5 times. The stretching ratio can be adjusted depending on the purpose.

[0080] The thickness of the film is not particularly limited and may be appropriately selected depending on the purpose, etc. In the case of a single-layer polyamide film, the thickness of the film can be, for example, 10 μm to 300 μm in the case of an unstretched film, and 5 μm to 100 μm in the case of a stretched film.

[0081] Polyamide films exhibit excellent pinhole resistance. The pinhole resistance can be evaluated by carrying out a 1000-time bending test at 5°C on an unstretched polyamide film using a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.) in accordance with MIL-B-131C, placing the film on a recording paper, applying India ink, and counting the number of black dots recorded on the recording paper. If the number of black dots counted is 115 or less per 0.03 m, the ... using a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.) in accordance with MIL-B-131C, placing the film on a recording paper, applying India ink, and counting the number of black dots recorded on the recording paper. If the number of black dots counted is 115 or less per 0.03 m, the pinhole resistance can be evaluated by carrying out a 1000-time bending test using a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.) 2 and more preferably 100 or less per 0.03 m 2 and more preferably 90 or less per 0.03 m 2 It is.

[0082] Moreover, the polyamide film exhibits the characteristic that the appearance is not deteriorated due to film gels. Specifically, the number of film gels can be evaluated using a fish eye counting device manufactured by Hutec Co., Ltd. The pellet mixture is fed to a single screw extruder equipped with a T-die (a T-die film molding machine with 25 mm diameter manufactured by GM Engineering Co., Ltd.) to produce an unstretched polyamide film with a thickness of 40 μm, and the number of gels is counted by counting the number of gels by 0.04 m using the fish eye counting device. 2 The number of film gels with a diameter of 50 μm or more per unit area is measured online.

[0083] The haze ratio of the polyamide film is preferably 20% or less, more preferably 18% or less, and even more preferably 16% or less, where the haze ratio of the polyamide film is measured in accordance with ASTM D-1003.

[0084] The polyamide film preferably has a gloss value of 75% or more, more preferably 80% or more, and even more preferably 85% or more, where the gloss value of the polyamide film is measured in accordance with ASTM D-523.

[0085] [Film laminate] The film laminate includes at least one layer of polyamide film. The method for producing the film laminate includes a method including a step of laminating an additional layer on one or both sides of the polyamide film. The lamination method is not particularly limited, and includes the co-extrusion method, extrusion lamination method, dry lamination method, etc. described in JP 2011-225870 A, and the co-extrusion method is preferable from the viewpoint of economic efficiency. The produced film laminate may be stretched to form a stretched film laminate. In that case, the produced film laminate may be uniaxially stretched to form a uniaxially stretched film laminate, or biaxially stretched (simultaneous biaxial stretching, sequential biaxial stretching) to form a biaxially stretched film laminate. The stretching method and stretching ratio are as described in the section on polyamide film.

[0086] (Further layers) The additional layer is not particularly limited as long as the film laminate exhibits the effect of the polyamide film, and examples thereof include a thermoplastic resin layer and an adhesive resin layer. Here, the adhesive resin layer is appropriately selected for the purpose of improving the adhesion and moldability between the polyamide film layer and the thermoplastic resin layer according to the present invention. Note that the polyamide film layer according to the present invention is not a thermoplastic resin layer or an adhesive resin layer.

[0087] The thermoplastic resin layer is a layer containing a thermoplastic resin, specifically a layer made of a thermoplastic resin or a layer made of a thermoplastic resin composition containing a thermoplastic resin (hereinafter, a thermoplastic resin composition containing a thermoplastic resin is also referred to as a "thermoplastic resin composition.") Specifically, the thermoplastic resin composition is a composition made of a thermoplastic resin and an additive.

[0088] Examples of the thermoplastic resin include non-polar polyolefins (e.g., low-density polyethylene, linear low-density polyethylene, ethylene / α-olefin copolymer having 3 to 8 carbon atoms, propylene homopolymer, copolymer of propylene and α-olefin having 4 to 8 carbon atoms, etc.), ionomers, ethylene / acrylic acid copolymers, ethylene / vinyl acetate copolymers, ethylene / acrylic acid ester copolymers, ethylene / methacrylic acid copolymers, polyesters, polyvinyl alcohols, polyamide resins, etc. Note that the thermoplastic resin layer containing a polyamide resin is not the polyamide film layer according to the present invention. The thermoplastic resin may have heat fusion properties. Examples of such thermoplastic resins having heat fusion properties include low-density polyethylene, linear low-density polyethylene, ethylene / α-olefin copolymer having 3 to 8 carbon atoms, ionomers, ethylene / acrylic acid copolymers, ethylene / vinyl acetate copolymers, ethylene / acrylic acid ester copolymers, and ethylene / methacrylic acid copolymers.

[0089] The thermoplastic resin is preferably a non-polar polyolefin, an ethylene / vinyl acetate copolymer, or a thermoplastic resin having heat fusion properties. When the thermoplastic resin is a non-polar polyolefin, the water vapor barrier property of the film laminate tends to be improved. When the thermoplastic resin is an ethylene / vinyl acetate copolymer layer, the oxygen gas permeability of the film laminate tends to be reduced. In addition, when the thermoplastic resin is a thermoplastic resin having heat fusion properties, when the polyamide film is used as a deep drawing packaging film, the heat fusion temperature with the deep drawing packaging lid material can be kept as low as possible, which tends to improve production efficiency.

[0090] The adhesive resin layer is a layer containing an adhesive resin, specifically a layer made of an adhesive resin or a layer made of an adhesive resin composition containing an adhesive resin (hereinafter, an adhesive resin composition containing an adhesive resin is also referred to as an "adhesive resin composition"). Specifically, the adhesive resin composition is a composition made of an adhesive resin and an additive. The adhesive resin is not particularly limited, and examples thereof include acid-modified polyolefin resins such as acid-modified polyethylene grafted with at least one monomer selected from unsaturated carboxylic acids and their derivatives.

[0091] The additives contained in the thermoplastic resin composition and the adhesive resin composition include the antioxidants and antiblocking agents described in the polyamide resin composition, as well as other additives.

[0092] (Layer composition) Specific examples of the layer structure of the film laminate include two layers of a polyamide film and a thermoplastic resin layer, three layers of a polyamide film / adhesive resin layer / thermoplastic resin layer, at least three layers of a polyamide film and a thermoplastic resin layer, and at least one additional layer selected from the group consisting of a polyamide film, an adhesive resin layer, and a thermoplastic resin layer, and at least four layers of a polyamide film, a thermoplastic resin layer, and an adhesive resin layer, and at least one additional layer selected from the group consisting of a polyamide film, an adhesive resin layer, and a thermoplastic resin layer. Specific examples include polyamide film / adhesive resin layer / thermoplastic resin layer, polyamide film / adhesive resin layer / thermoplastic resin layer / adhesive resin layer / thermoplastic resin layer, thermoplastic resin layer / adhesive resin layer / polyamide film / adhesive resin layer / thermoplastic resin layer, and the like. Here, the adhesive resin layer can be provided as necessary. In addition, when the film laminate is an unstretched film laminate and a deep drawing packaging film, it is preferable that the thermoplastic resin layer is an inner layer. In the film laminate, the layer in contact with the outside air is the outer layer, and the layer in contact with the food product to be packaged is the inner layer.

[0093] (Thickness) The thickness of the film laminate is not particularly limited and can be selected depending on the application. The thickness of each polyamide film layer in the film laminate can be 1 to 300 μm, preferably 2 to 100 μm, and more preferably 5 to 80 μm. The thickness of each thermoplastic resin layer can be appropriately selected depending on the purpose, and is preferably in the range of, for example, 8 to 120 μm. The thickness of each adhesive resin layer can be selected depending on the purpose, and is preferably in the range of, for example, 1 to 100 μm. The total thickness of the film laminate is not particularly limited and is preferably 5 to 500 μm, more preferably 20 to 300 μm, and particularly preferably 50 to 200 μm.

[0094] [Application] The polyamide resin composition can be used as a raw material for various molded products. The molded products containing the polyamide resin composition can be used for a wide range of applications, such as food packaging films, automobile parts, computers and related devices, optical device parts, electric and electronic devices, information and communication devices, precision devices, civil engineering and construction supplies, medical supplies, and household goods, and are particularly useful as food packaging films.

[0095] The polyamide film and the film laminate are free from the deterioration of appearance caused by film gel and have excellent pinhole resistance in a low-temperature environment, and therefore the film laminate can be suitably used for packaging products, particularly food packaging.

[0096] The unstretched polyamide film and the unstretched film laminate are excellent in deep drawing property, and therefore can be suitably used as a food packaging film, particularly as a deep drawing packaging film for food. When the unstretched polyamide film is used as a deep drawing packaging film, the food is placed in the deep drawing packaging base material obtained by deep drawing the film, and packaged using a lid material. Examples of the food to be placed in the deep drawing packaging base material include sliced ​​foods such as ham and cheese. The lid material is not particularly limited and can be appropriately selected according to the purpose.

[0097] Stretched polyamide films and stretched film laminates have excellent mechanical strength and oxygen barrier properties, and are therefore useful as food packaging films for filling and packaging semi-liquid foods such as sausages (paste products) and solid foods such as processed meats and hams. EXAMPLES

[0098] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples, and can be practiced with appropriate modifications within the scope of the present invention.

[0099] [Raw materials used] The raw materials used in the examples and comparative examples are as follows. (1) Polyamide resin (A) Polyamide resin (A-1): Polyamide 6 (relative viscosity measured in accordance with JIS K-6920 in 96% sulfuric acid at a polymer concentration of 10 mg / ml and at 25°C: 3.4) (2) Ethylene / α-olefin copolymer (B) Ethylene / butene copolymer (B-1): Toughmer (registered trademark) DF740 manufactured by Mitsui Chemicals, Inc. (melt flow rate measured at 190°C and a load of 2.16 kg: 3.6 g / 10 min, density measured according to ASTM D1505: 870 kg / m 3 ) (3) Metal salt of ethylene / methacrylic acid copolymer (C) Partial zinc salt of ethylene / methacrylic acid copolymer (C-1): Himilan (registered trademark) 1706, manufactured by Dow Mitsui Polychemicals Co., Ltd. (Melt flow rate measured at 190°C and a load of 2.16 kg: 0.9 g / 10 min) (4) Antioxidants (D) Antioxidant (D-1): Irganox (registered trademark) 1010, manufactured by BASF Japan Ltd. Antioxidant (D-2): Irgafos (registered trademark) 168, manufactured by BASF Japan Ltd. (5) Hydrolyzate of ethylene / vinyl acetate copolymer (F) Hydrolyzate of ethylene / vinyl acetate copolymer (F-1): Mersen (registered trademark) H-6051K, manufactured by Tosoh Corporation

[0100] Example 1 As the first polyamide resin (A1), 7.95% by mass of polyamide resin (A-1) was added with 1.80% by mass of ethylene / butene copolymer (B-1), 0.53% by mass of partial zinc salt of ethylene / methacrylic acid copolymer (C-1), 0.21% by mass of antioxidant (D-1), and 0.11% by mass of antioxidant (D-2), and melt-kneaded to prepare the first pellet of the melt-kneaded product (E). Next, the second pellet was prepared using polyamide resin (A-1) as the second polyamide resin (A2). Finally, 10.6% by mass of the first pellet and 89.4% by mass of the second pellet were dry-blended to obtain a pellet mixture. The composition of the pellet mixture of Example 1 is shown in Table 1.

[0101] Using the pellet mixture of Example 1, unstretched polyamide films a, c, and d and biaxially stretched polyamide film b were produced as follows.

[0102] Unstretched polyamide film a The pellet mixture of Example 1 was used with a T-die film molding machine with 40 mmφEx manufactured by Plastics Technology Research Institute Co., Ltd. to produce an unstretched polyamide film a with a thickness of 30 μm.

[0103] Biaxially oriented polyamide film b An unstretched polyamide film having a thickness of 100 μm was produced using the pellet mixture of Example 1 and a 40 mmφEx T-die film molding machine manufactured by Plastics Engineering Research Institute Co., Ltd. The unstretched polyamide film thus obtained was stretched at a stretching temperature of 100° C. by a biaxial stretching machine manufactured by Iwamoto Seisakusho Co., Ltd., stretching 3.0 times in the vertical direction and 3.0 times in the horizontal direction to a total of 9.0 times, thereby producing a biaxially stretched polyamide film b having a thickness of 15 μm.

[0104] Unstretched polyamide film c The pellet mixture of Example 1 was fed to a single-screw extruder equipped with a T-die (a T-die film molding machine having an ex diameter of 25 mm, manufactured by GM Engineering Co., Ltd.) to produce an unstretched polyamide film c having a thickness of 40 μm.

[0105] Unstretched polyamide film d The pellet mixture of Example 1 was fed to a single-screw extruder equipped with a T-die (a T-die film molding machine with 40 mmφEx manufactured by Plastics Technology Research Institute Co., Ltd.) to produce an unstretched polyamide film d having a thickness of 100 μm.

[0106] Examples 2-3 and Comparative Examples 1-2 Pellet mixtures and polyamide films a to d of Examples 2 and 3 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the types and ratios of each component were changed as shown in Table 1.

[0107] [Table 1]

[0108] [evaluation] The following properties were evaluated for each of the polyamide films produced in Examples 1 to 3 and Comparative Examples 1 and 2. The evaluation results are shown in Table 2.

[0109] 1.Pinhole resistance in low temperature environments For the unstretched polyamide films a obtained in Examples 1 to 3 and Comparative Examples 1 and 2, a bending test was carried out 1000 times at 5°C according to MIL-B-131C using a thermostatic chamber-equipped Gelbo Flex Tester manufactured by Tester Sangyo Co., Ltd. After the bending test, the film was placed on a recording paper, and then India ink was applied and allowed to penetrate the recording paper, and the number of recorded black dots was counted. The pinhole resistance was evaluated according to the following criteria. ◎: The number of black spots is 90 or less / 0.03m 2 ○: The number of black spots is more than 90 to 115 / 0.03m 2 ×: The number of black spots is more than 115 / 0.03m 2

[0110] 2. Haze value (Haze ratio) The haze value (haze ratio) of the biaxially stretched polyamide film b was measured using a Haze Meter manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with ASTM D-1003.

[0111] 3. Glossiness (gloss value) The gloss (gloss value) of the biaxially oriented polyamide film b was measured using a digital variable angle glossmeter manufactured by Suga Test Instruments Co., Ltd. in accordance with ASTM D-523.

[0112] 4. Number of film gels The number of film gels was measured for the unstretched polyamide films c obtained in Examples 1 to 3 and Comparative Examples 1 and 2. The unstretched polyamide films c were counted at intervals of 0.04 m using a fish eye counting device manufactured by Hutec Corporation. 2The number of film gels with diameters of 50 to 99 μm, 100 to 199 μm, and 200 μm or more per unit area was measured online, and the number of film gels generated (pieces / 0.04 m 2 In Table 2, the number of film gels is the average value of 50 measurements.

[0113] 5. Visual Evaluation of Film Gels The unstretched polyamide films d obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were visually evaluated for the degree of visibility of the film gels in the films and judged according to the following criteria: The more "+" there are, the more noticeable the gels are, and the poorer the appearance is, and "++" means that there is no problem in practical use. Visual judgment: (not noticeable) “+” to “++++” (not noticeable)

[0114] [Table 2]

[0115] From Table 2, it can be seen that Examples 1 to 3, which use polyamide resin compositions containing 86.4 to 99.2 mass% of polyamide resin (A), 0.1 to 10.0 mass% of ethylene / α-olefin copolymer (B), and 0.1 to 10.0 mass% of metal salt of ethylene / methacrylic acid copolymer (C) in 100 mass% of polyamide resin composition, have excellent pinhole resistance in low temperature environment, film gel is not noticeable, and film appearance is excellent. Example 1, which uses a polyamide resin composition containing 1.6 to 2.0 mass% of ethylene / α-olefin copolymer (B) and 0.50 to 0.60 mass% of metal salt of ethylene / methacrylic acid copolymer (C) in 100 mass% of polyamide resin composition, has excellent pinhole resistance and film appearance in low temperature environment, and is particularly preferable.

[0116] In Comparative Examples 1 and 2, in which a hydrolyzate of an ethylene / vinyl acetate copolymer was used instead of the ethylene / α-olefin copolymer (B), the film gel was noticeable and the appearance was deteriorated. Furthermore, in Comparative Example 2, the pinhole resistance in a low temperature environment was poor. [Industrial Applicability]

[0117] The polyamide resin composition of the present invention can provide a polyamide film that maintains various properties such as gas barrier properties, toughness, pinhole resistance, heat resistance, transparency, etc., and further does not suffer from deterioration in appearance due to film gel and has excellent pinhole resistance in a low temperature environment. The film obtained from the polyamide resin composition of the present invention is particularly suitable for use in food packaging applications, etc.

Claims

1. A polyamide resin composition comprising, per 100 mass% of the polyamide resin composition, 86.4 to 99.2 mass% of a polyamide resin (A), 0.1 to 10.0 mass% of an ethylene / α-olefin copolymer (B), and 0.1 to 0.9 mass% of a metal salt of an ethylene / methacrylic acid copolymer (C), and the mass ratio (C / B) of the metal salt of the ethylene / methacrylic acid copolymer (C) to the ethylene / α-olefin copolymer (B) is 0.04 to 0.

60.

2. 2. The polyamide resin composition according to claim 1, wherein the polyamide resin (A) is selected from the group consisting of polyamide 6, polyamide 6 / 66, polyamide 6 / 12 and polyamide 6 / 66 / 12.

3. 3. The polyamide resin composition according to claim 1, further comprising 0.01 to 0.6 mass% of an antioxidant based on 100 mass% of the polyamide resin composition, the antioxidant being at least one selected from the group consisting of phenol-based compounds, phosphorus-based compounds, and sulfur-based compounds.

4. The polyamide resin composition according to any one of claims 1 to 3, further comprising an antiblocking agent.

5. A polyamide film comprising the polyamide resin composition according to any one of claims 1 to 4.

6. The polyamide film according to claim 5 , which is a stretched film.

7. A film laminate comprising the polyamide film according to claim 5 or 6.

8. The film laminate according to claim 7, which is for food packaging.

9. First pellets containing a first polyamide resin (A1), an ethylene / α-olefin copolymer (B), and a metal salt of an ethylene / methacrylic acid copolymer (C); and Second pellets containing a second polyamide resin (A2) A pellet mixture comprising: The first pellets contain, in an amount of 100 mass% of the first pellets, 69.4 to 97.4 mass% of a first polyamide resin (A1), 1.0 to 20.0 mass% of an ethylene / α-olefin copolymer (B), and 1.0 to 20.0 mass% of a metal salt of an ethylene / methacrylic acid copolymer (C), The pellet mixture contains, in 100 mass% of a kneaded product obtained by melt-kneading the pellet mixture, a total of 86.4 to 99.2 mass% of a first polyamide resin (A1) and a second polyamide resin (A2), 0.1 to 10.0 mass% of an ethylene / α-olefin copolymer (B), and 0.1 to 0.9 mass% of a metal salt of an ethylene / methacrylic acid copolymer (C), and in the kneaded product, a mass ratio (C / B) of the metal salt of an ethylene / methacrylic acid copolymer (C) to the ethylene / α-olefin copolymer (B) is 0.04 to 0.

60.

10. A method for producing the polyamide resin composition according to any one of claims 1 to 4, comprising melt-kneading the pellet mixture according to claim 9.

11. A method for producing the polyamide film according to claim 5 or 6, comprising melt-kneading the pellet mixture according to claim 9 to form a film.

12. A method for producing the film laminate according to claim 7 or 8, comprising melt-kneading the pellet mixture according to claim 9 to form a polyamide film.

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