Multilayer structures and packaging materials using the same

Abstract

This invention provides a multilayer film that is excellent in appearance, recyclability, flexibility, and quality stability, and is suitable for use as packaging material for food, beverages, pharmaceuticals, cosmetics, and other agricultural materials. [Solution] A multilayer film having a layer structure in which a polyolefin layer (A), an adhesive resin layer (B), and an EVOH layer (C) are laminated in this order, wherein the EVOH layer (C) contains EVOH(c1) with an ethylene unit content of 20 mol% to 60 mol%, a degree of saponification of 90 mol% or more, and a hydrophobic plasticizer (c2), the EVOH(c1) content in the EVOH layer (C) is 60% by mass to 99.9% by mass, and the EVOH(c1) constituting the EVOH layer (C) The ethylene unit content is 30 mol% or more and 60 mol% or less on average, the hydrophobic plasticizer (c2) content in the EVOH layer (C) is 0.1% by mass or more and 3% by mass or less, the EVOH layer (C) may further contain a phosphate compound (c3) in terms of phosphate roots of 500 ppm or less, the EVOH resin composition layer (C) does not contain nylon 6, and the thickness ratio of the EVOH resin composition layer (C) to the total thickness of the multilayer film is 7.5% or less, and this is a multilayer film.

Description

[Technical Field] 【0001】 The present invention relates to multilayer films, food packaging materials, beverage packaging materials, pharmaceutical packaging materials, cosmetic packaging materials, agricultural materials, recovered compositions, and methods for producing recovered compositions. [Background technology] 【0002】 Conventionally, laminated films having a polyamide resin layer (sometimes referred to as nylon) or an ethylene-vinyl alcohol copolymer (sometimes referred to as EVOH) layer and a polyolefin resin layer have been used as transparent, high-mechanism-strength oxygen barrier (gas barrier) packaging materials. Furthermore, to improve the strength of the laminated film, a laminated film is known in which nylon layers are arranged on both sides of the EVOH layer, and a polyolefin resin layer is arranged on the outside of that (Patent Document 1). 【0003】 In recent years, driven by environmental and waste issues, there has been a growing global demand for so-called post-consumer recycling (hereinafter sometimes simply referred to as recycling), which involves collecting and recycling packaging materials consumed in the market. In recycling, the collected packaging materials are generally cut, separated and washed as needed, and then melted and mixed using an extruder. Due to their high processing temperature and poor compatibility with polyolefins, polyamide resins (nylon) are difficult to uniformly mix with polyolefins in the melting and mixing process when collected and recycled, thus hindering recycling. For example, the laminated film described in Patent Document 1 had the problem that when it was collected and reused, the polyamide resin and EVOH chemically reacted, causing crosslinking and generating lumps, which reduced its recyclability. Therefore, there was a desire for the development of a laminated film that does not contain a polyamide layer. 【0004】 Patent Document 2 describes a multilayer structure as a laminated film that does not contain a polyamide layer, having a hard layer with a puncture strength of 40 N / mm to 150 N / mm and a resin composition layer made of a specific EVOH. It is stated that such a multilayer structure has excellent mechanical strength and thermoformability, and that when the recovered material is melt-molded, the generation of defects due to resin degradation (gelation) is suppressed. [Prior art documents] [Patent Documents] 【0005】 [Patent Document 1] Japanese Patent Publication No. 2001-79996 [Patent Document 2] International Publication No. 2020 / 071513 [Overview of the Initiative] [Problems that the invention aims to solve] 【0006】 However, it was found that the multilayer structure described in Patent Document 2 has a problem in that strong shear stress is applied between the adhesive resin layer and the resin composition layer made of a specific EVOH during film formation, causing unevenness in the thickness of the resin composition layer and disruption of the layer interface, resulting in a deterioration of the film appearance. Furthermore, the inventors have discovered for the first time that this deterioration of the film appearance is particularly noticeable when the proportion of the thickness of the resin composition layer made of a specific EVOH in the multilayer structure is low. Moreover, it was found that when additives are added to solve this problem, depending on the type and amount of additives, the resin pressure of the extruder used when forming the resin composition layer made of a specific EVOH may become unstable, which may reduce the quality stability of the product. 【0007】 The present invention was made to solve the above problems and aims to provide multilayer films, food packaging materials, beverage packaging materials, pharmaceutical packaging materials, cosmetic packaging materials, and agricultural materials that are excellent in appearance, recyclability, flexibility, and quality stability. Another object of the present invention is to provide a recovery composition and a method for producing the same that can suppress the occurrence of fish eyes when a recovery composition containing the recovered multilayer film of the present invention is formed into a film. [Means for solving the problem] 【0008】 In other words, the above problem is, [1] A multilayer film having a layer structure in which a polyolefin layer (A) (hereinafter sometimes abbreviated as "PO layer (A)"), an adhesive resin layer (B), and an ethylene-vinyl alcohol copolymer resin composition layer (C) (hereinafter sometimes abbreviated as "EVOH resin composition layer (C)") are laminated in this order, wherein the EVOH resin composition layer (C) contains an ethylene-vinyl alcohol copolymer resin (c1) (hereinafter sometimes abbreviated as "EVOH resin (c1)") with an ethylene unit content of 20 mol% or more and 60 mol% or less and a degree of saponification of 90 mol% or more, and a hydrophobic plasticizer (c2), and the content of EVOH resin (c1) in the EVOH resin composition layer (C) is 60% by mass or more and 99.9% by mass. A multilayer film having a mass of % or less, where the average ethylene unit content of the EVOH resin (c1) constituting the EVOH resin composition layer (C) is 30 mol% or more and 60 mol% or less, the hydrophobic plasticizer (c2) content in the EVOH resin composition layer (C) is 0.1 mass% or more and 3 mass% or less, the EVOH resin composition layer (C) may further contain a phosphate compound (c3), and if the EVOH resin composition layer (C) contains a phosphate compound (c3), its content is 500 ppm or less in terms of phosphate roots, the EVOH resin composition layer (C) does not contain nylon 6, and the thickness ratio of the EVOH resin composition layer (C) to the total thickness of the multilayer film is 7.5% or less; [2] A multilayer film of [1] wherein the hydrophobic plasticizer (c2) contained in the EVOH resin composition layer (C) is an aliphatic ester; [3] A multilayer film according to [1] or [2], wherein the thickness ratio of the EVOH resin composition layer (C) to the total thickness of the multilayer film is 5% or less; [4] A multilayer film of any of [1] to [3], wherein the hydrophobic plasticizer (c2) content in the EVOH resin composition layer (C) is 0.6% by mass or more and 3% by mass or less; [5] A multilayer film of any of the following types: [1] to [4], wherein the EVOH resin composition layer (C) contains a thermoplastic resin (c4) different from the EVOH resin (c1), and the mass ratio (c4 / c1) of the thermoplastic resin (c4) to the EVOH resin (c1) in the EVOH resin composition layer (C) is 10 / 90 to 40 / 60; [6] A multilayer film of [5] comprising an acid-modified polyolefin, wherein the thermoplastic resin (c4) is... [7] A multilayer film of [5] comprising a thermoplastic resin (c4) having an ethylene unit content of more than 60 mol% of an EVOH resin; [8] A multilayer film of [5] comprising at least one thermoplastic resin (c4) selected from the group consisting of nylon 6 / 12, nylon 6 / 66, and nylon 6 / 66 / 12; [9] A multilayer film of any of [1] to [8], wherein the polyolefin resin constituting the polyolefin layer (A) is at least one selected from the group consisting of low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and polypropylene;

[10] A multilayer film of any of [1] to [9], wherein the polyolefin resin constituting the polyolefin layer (A) is a metallocene polyolefin polymerized using a metallocene catalyst; Food packaging materials, beverage packaging materials, pharmaceutical packaging materials, cosmetic packaging materials, or agricultural materials using any of the multilayer films described in

[11] [1] to

[10] ; A recovery composition containing recovered multilayer film material from any of

[12] [1] to

[10] ; A method for producing a recovered composition, comprising the step of melting and kneading the recovered material of any of the multilayer films from [1] to

[10] ; This is solved by providing [the solution]. [Effects of the Invention] 【0009】 The present invention provides a multilayer film excellent in appearance, recyclability, flexural resistance, and quality stability, as well as packaging materials such as food packaging materials, beverage packaging materials, pharmaceutical packaging materials, cosmetic packaging materials, and agricultural materials using the same. Furthermore, it provides a recovery composition that can suppress the occurrence of fish eyes when a recovery composition containing the recovered multilayer film of the present invention is formed into a film, and a method for producing the same. The appearance, recyclability, flexural resistance, and quality stability described herein can be evaluated by the methods described in the examples below. "Appearance" can be evaluated by visually checking for the presence or absence of irregularities in the multilayer film, as described in the examples. "Recyclability" can be evaluated by the number of fish eyes when a film is formed using the recovered multilayer film of the present invention, as described in the examples. "Flexural resistance" can be evaluated by the number of pinholes after a bending test, as described in the examples. "Quality stability" can be evaluated by observing the fluctuations in the resin pressure of the extruder for the EVOH resin composition layer (C), as described in the examples. [Modes for carrying out the invention] 【0010】 The multilayer film of the present invention is a multilayer film having a layer structure in which a PO layer (A), an adhesive resin layer (B), and an EVOH resin composition layer (C) are laminated in this order, wherein the EVOH resin composition layer (C) contains an EVOH resin (c1) with an ethylene unit content of 20 mol% or more and 60 mol% or less, a degree of saponification of 90 mol% or more, and a hydrophobic plasticizer (c2), the content of the EVOH resin (c1) in the EVOH resin composition layer (C) is 60% by mass or more and 99.9% by mass or less, and the ethylene unit content of the EVOH resin (c1) constituting the EVOH resin composition layer (C) is The average value is 30 mol% or more and 60 mol% or less, the content of hydrophobic plasticizer (c2) in the EVOH resin composition layer (C) is 0.1% by mass or more and 3% by mass or less, the EVOH resin composition layer (C) may further contain a phosphate compound (c3), and if the EVOH resin composition layer (C) contains a phosphate compound (c3), its content is 500 ppm or less in terms of phosphate, the EVOH resin composition layer (C) does not contain nylon 6, and the thickness ratio of the EVOH resin composition layer (C) to the total thickness of the multilayer film is 7.5% or less. 【0011】 Here, the PO layer (A) means a layer mainly composed of a polyolefin resin. Here, the main component means a component with a content of more than 50% by mass in that layer. The adhesive resin layer (B) means a layer containing an adhesive resin. That the average value of the ethylene unit content of the EVOH resin (c1) constituting the EVOH resin composition (C) is 30 mol% or more and 60 mol% or less means that when the EVOH resin (c1) constituting the EVOH resin composition (C) is a single species, the ethylene unit content of the EVOH resin (c1) is 30 mol% or more and 60 mol% or less, and when the EVOH resin (c1) is used as a mixture of two or more species, it means that the average value calculated from the mixing mass ratio is 30 mol% or more and 60 mol% or less. For example, when the EVOH resin composition (C) contains 80 parts by mass of an EVOH resin with an ethylene unit content of 27 mol% and 20 parts by mass of an EVOH resin with an ethylene unit content of 44 mol% as the EVOH resin (c1), the average value of the ethylene unit content of the EVOH resin (c1) is 30.4 mol%. In this specification, a film means a layered product having a thickness of less than 400 μm. The total thickness of the multilayer film means the sum of the thicknesses of all the layers constituting the multilayer film. 【0012】 The multilayer film of the present invention has a layer structure in which a PO layer (A), an adhesive resin layer (B), and an EVOH resin composition layer (C) are laminated in this order, and thus tends to have excellent flex resistance. When the EVOH resin composition layer (C) contains a hydrophobic plasticizer (c2) in an amount of 0.1% by mass or more and 3% by mass or less, even if it has a layer structure in which the PO layer (A), the adhesive resin layer (B), and the EVOH resin composition layer (C) are laminated in this order, it has excellent appearance and tends to have excellent quality stability. Further, when the EVOH resin composition layer (C) contains a phosphate compound (c3), setting its content to 500 ppm or less tends to improve recyclability. Further, when the EVOH resin composition layer (C) does not contain nylon 6, the recyclability tends to be good. Furthermore, when the thickness ratio of the EVOH resin composition layer (C) to the total thickness of the multilayer film of the present invention is 7.5% or less, the recyclability is good, while the appearance tends to deteriorate. That is, it can be said that the multilayer film of the present invention is an excellent invention that not only has excellent recyclability, but can also suppress deterioration of appearance and flex resistance caused by its structure, and can further suppress deterioration of quality stability that may occur due to the addition of a plasticizer. 【0013】 (PO layer (A)) The multilayer film of the present invention includes a PO layer (A), and thus tends to have excellent recyclability and flex resistance. The proportion of the polyolefin resin, which is the main component of the PO layer (A), occupying the PO layer (A) is more than 50% by mass, preferably 70% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and may be 99% by mass or more, or even 100% by mass. 【0014】 The density of the polyolefin resin constituting the PO layer (A) is 0.850 g / cm 3 or more and 0.970 g / cm 3 or less, which is preferable from the viewpoint of flex resistance. The density is more preferably 0.930 g / cm 3 or less, still more preferably 0.920 g / cm 3 or less, particularly preferably 0.910 g / cm 3 or less. 【0015】 Examples of the polyolefin resin include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), very low-density polyethylene (VLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), olefin-unsaturated carboxylic acid copolymer ionomer, ethylene-propylene copolymer, ethylene-acrylic acid ester copolymer, polypropylene, propylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymer, polybutene, polypentene, and other olefins alone or copolymers, graft-modified versions of these olefins alone or copolymers with unsaturated carboxylic acids or their esters, and blends thereof. Among these, it is preferable that at least one is selected from the group consisting of low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and polypropylene, and linear low-density polyethylene (LLDPE) or low-density polyethylene (LDPE) is more preferable from the viewpoint of flexural resistance, with linear low-density polyethylene (LLDPE) being even more preferable. 【0016】 The above polyolefin resin is preferably a metallocene polyolefin polymerized using a metallocene catalyst, and more preferably an ethylene polymer or copolymer polymerized using a metallocene catalyst. An ethylene polymer or copolymer polymerized using a metallocene catalyst is a homopolymer of ethylene or a copolymer of ethylene and an α-olefin having 3 or more carbon atoms, and is produced by polymerizing ethylene or copolymerizing ethylene and an α-olefin having 3 or more carbon atoms in the presence of a catalyst formed from a transition metal of Group 4 of the periodic table, preferably zirconium, an organoaluminum oxy compound, and various components added as needed, having at least one ligand having a cyclopentadienyl skeleton. 【0017】 Examples of α-olefins having 3 or more carbon atoms in the above-mentioned ethylene copolymer include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 4-methyl-1-pentene. As the above-mentioned ethylene copolymer, a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms is particularly preferred. 【0018】 Ethylene polymers or copolymers polymerized using metallocene catalysts are commercially available on an industrial basis, such as "Kernel" (manufactured by Nippon Polychem Co., Ltd.), "Evolue" (manufactured by Prime Polymer Co., Ltd.), "Exact" (manufactured by ExxonMobil), and "Affinity" and "Engage" (manufactured by Dow Chemical). 【0019】 The aforementioned polyolefin resin may be used alone or in combination of two or more types. 【0020】 The thickness of each PO layer (A) is preferably 10 μm or more, and more preferably 15 μm or more. Furthermore, the thickness of each PO layer (A) is preferably 350 μm or less, more preferably 300 μm or less, and may also be 150 μm or less, 100 μm or less, or 75 μm or less. When the thickness of each PO layer (A) is within the above range, it tends to have excellent flexibility and heat sealability. In addition, the total thickness of all layers of the PO layer (A) constituting the multilayer film of the present invention is preferably 20 μm or more and 350 μm or less, and may also be 30 μm or more and 200 μm or less, or 40 μm or more and 150 μm or less. 【0021】 The ratio of the thickness of the PO layer (A) to the total thickness of the multilayer film of the present invention is preferably 70% or more, more preferably 75% or more, and even more preferably 80% or more. When the thickness of the PO layer (A) is 70% or more, the recyclability and flexibility tend to be excellent. The ratio of the thickness of the PO layer (A) may be 98% or less. 【0022】 (EVOH resin composition layer (C)) The multilayer film of the present invention has good gas barrier properties because it contains an EVOH resin composition layer (C). The EVOH resin composition layer (C) contains 60% to 99.9% by mass of EVOH resin (c1), 0.1% to 3% by mass of hydrophobic plasticizer (c2), and does not contain nylon 6. 【0023】 The EVOH resin composition layer (C) contains 60% to 99.9% by mass of EVOH resin (c1), and therefore exhibits excellent gas barrier properties. The content of EVOH resin (c1) is preferably 99.7% by mass or less, more preferably 99.4% by mass or less, and even more preferably 99.2% by mass or less. The content of EVOH resin (c1) in the EVOH resin composition layer (C) is such that EVOH resin (c1) is a copolymer mainly consisting of ethylene units and vinyl alcohol units, obtained by saponifying the vinyl ester units in the ethylene-vinyl ester copolymer, and can be produced by known manufacturing methods. 【0024】 The ethylene unit content of EVOH resin (c1) is 20 mol% or more, preferably 25 mol% or more, more preferably 32 mol% or more, even more preferably 35 mol% or more, particularly preferably 42 mol% or more, and sometimes preferably 45 mol% or more. Furthermore, the ethylene unit content is 60 mol% or less, more preferably 55 mol% or less, and sometimes preferably 50 mol% or less. When the ethylene unit content of EVOH resin (c1) is within the above range, it tends to exhibit good gas barrier properties and recyclability. 【0025】 The average ethylene unit content of the EVOH resin (c1) constituting the EVOH resin composition layer (C) is 30 mol% or more and 60 mol% or less. If the average ethylene unit content is less than 30 mol%, the thermal stability during melt molding decreases, and recyclability may deteriorate. For example, if EVOH with an ethylene unit content of 29 mol% is used alone as the EVOH resin (c1), recyclability tends to deteriorate. On the other hand, even if EVOH with an ethylene unit content of 29 mol% is used as the EVOH resin (c1), if other EVOH resins (c1) are used simultaneously to bring the average ethylene unit content of the EVOH resin (c1) to 30 mol% or more and 60 mol% or less, recyclability tends to improve. The average ethylene unit content is preferably 32 mol% or more, and more preferably 44 mol% or more. Furthermore, if the average ethylene unit content exceeds 60 mol%, the gas barrier properties may become insufficient. The average ethylene unit content is preferably 55 mol% or less. 【0026】 The degree of saponification of the EVOH resin (c1) is 90 mol% or higher. If the degree of saponification is less than 90 mol%, the crystallinity of EVOH decreases, reducing its gas barrier properties and significantly lowering its thermal stability during melt molding. The degree of saponification is preferably 95 mol% or higher, more preferably 98 mol% or higher, and even more preferably 99 mol% or higher. 【0027】 The EVOH resin (c1) may contain units derived from monomers other than ethylene, vinyl esters, and their saponifies. When the EVOH resin (c1) contains the aforementioned other monomer units, the content of these other monomer units relative to the total structural units of the EVOH resin (c1) is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and particularly preferably 5 mol% or less. Furthermore, when the EVOH resin (c1) contains the aforementioned other monomer-derived units, the lower limit may be 0.05 mol% or 0.10 mol%. Other monomers include, for example, alkenes such as propylene, butylene, pentene, and hexene; 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4-diasiloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, and 4-acyloxy-3-methyl -1-butene, 3,4-diasiloxy-2-methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diasiloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, 5,6-diasiloxy-1-hexene, 1,3-diacetoxy-2-methyl Examples include alkenes having ester groups such as npropane or their saponides; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid, or their anhydrides, salts, or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefin sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, and methallylsulfonic acid, or their salts; vinylsilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxy-ethoxy)silane, and γ-methacryloxypropylmethoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, and vinylidene chloride. The EVOH resin (c1) may be post-modified by methods such as urethaneization, acetalization, cyanoethylation, and oxyalkyleneization. 【0028】 The EVOH resin (c1) may be used alone or in combination of two or more. When the EVOH resin (c1) is used in combination of two or more, from the viewpoint of improving thermoformability while maintaining gas barrier properties, it is preferable to use in combination an EVOH resin having an ethylene unit content of 34 mol% or less and an EVOH resin having an ethylene unit content of 42 mol% or more, and it is more preferable to use in combination an EVOH resin having an ethylene unit content of 32 mol% or less and an EVOH resin having an ethylene unit content of 42 mol% or more. When an EVOH resin having an ethylene unit content of 34 mol% or less and an EVOH resin having an ethylene unit content of 42 mol% or more are used in combination, from the viewpoint of gas barrier properties, the mass ratio (W 34 / W 42 ) of the EVOH resin having an ethylene unit content of 34 mol% or less to the EVOH resin having an ethylene unit content of 42 mol% or more is preferably 50 / 50 or more, more preferably 60 / 40 or more, and still more preferably 70 / 30 or more. The mass ratio (W 34 / W 42 ) may be 90 / 10 or less or 85 / 15 or less. 【0029】 The EVOH resin composition layer (C) tends to have a good appearance while maintaining the quality stability of the multilayer film of the present invention by containing 0.1% to 3% by mass of a hydrophobic plasticizer (c2). Here, the inventors were the first to discover that when the thickness ratio of the EVOH resin composition layer (C) to the total thickness of the multilayer film of the present invention is 7.5% or less, a problem of deterioration in appearance occurs, and they were the first to discover that this problem can be solved by adding a specific amount of hydrophobic plasticizer (c2). Therefore, in multilayer films where the thickness ratio exceeds 7.5%, deterioration in appearance does not occur, and the effect of improving appearance by the hydrophobic plasticizer (c2) is not obtained. Furthermore, if a hydrophilic plasticizer is used instead of the hydrophobic plasticizer (c2), quality stability tends not to be maintained. The content of the hydrophobic plasticizer (c2) in the EVOH resin composition layer (C) is 0.1% by mass or more, preferably 0.3% by mass or more, more preferably 0.6% by mass or more, and even more preferably 0.8% by mass or more. If the hydrophobic plasticizer (c2) content is less than 0.1%, the appearance defects due to unevenness (streaky or uneven surface like the surface of an orange peel (orange peel)) that occurs after co-extrusion molding of the multilayer film become significant. Furthermore, the hydrophobic plasticizer (c2) content is 3% by mass or less, and more preferably 2.5% by mass or less. If the hydrophobic plasticizer (c2) content exceeds 3% by mass, the resin pressure of the extruder for the EVOH resin composition layer (C) becomes unstable during film formation of the multilayer film of the present invention, reducing the stability of the thickness of the EVOH layer, and as a result, product stability may not be maintained. 【0030】 The hydrophobic plasticizer (c2) is not particularly limited as long as it is hydrophobic, and examples include aliphatic esters and aromatic esters, with aliphatic esters being preferred from the viewpoint of improving the appearance of the multilayer film of the present invention. 【0031】 Suitable aliphatic esters include monoesters, diesters, or more polyesters of polyhydric alcohols (dihydric, trihydric, or more polyhydric alcohols) and higher fatty acids (higher fatty acids with 8 or more carbon atoms, preferably 8 to 30 carbon atoms). Examples of stearic acid esters include glycerin monostearate, glycerin mono-12-hydroxystearate, glycerin distearate, diglycerin monostearate, and tetraglycerin monostearate; and lauric acid esters include glycerin monolaurate, diglycerin monolaurate, and tetraglycerin monolaurate. Other fatty acid esters include polypropylene adipate, diisodecyl adipate, bis(2-methylhexyl) adipate, dicapryl adipate, diisooctyl adipate, octyldecyl adipate, isooctylisodecyl adipate, dibutyl fumarate, dioctyl fumarate, triethyl citrate, acetyl triethyl citrate, tributyl citrate, and acetyl tributyl citrate. 【0032】 Aromatic esters include dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, bis(2-ethylhexyl) phthalate, dicyclohexyl phthalate, butyl lauryl phthalate, diisooctyl phthalate, butyl coconut alkyl phthalate, ditridecyl phthalate, dilauryl phthalate, diisodecyl phthalate, butyl benzyl phthalate, octyldecanoyl phthalate, dimethyl glycol phthalate, ethyl phthalyl ethylene glycolate, methyl phthalyl ethylene glycolate, butyl phthalylbutylene glycolate, dinolyl phthalate, diheptyl phthalate, octyldecyl phthalate, ditridecyl phthalate, dicapryl phthalate, bis(3,5,5-trimethylhexyl) phthalate, isooctylisodecyl phthalate, bis(diethylene glycol monomethyl ether) phthalate, and benzophenol. 【0033】 The hydrophobic plasticizer (c2) may be used alone or in combination of two or more types. When two or more types of hydrophobic plasticizers (c2) are used in combination, it is preferable that the EVOH resin composition layer (C) contains at least 0.05% by mass of each hydrophobic plasticizer (c2) in order to stably exhibit the appearance improvement effect. The reason for this is not clear, but it is presumed that errors in the amount added at amounts less than 0.05% by mass affect the appearance improvement effect. 【0034】 The EVOH resin composition layer (C) may further contain a phosphate compound (c3). When the EVOH resin composition layer (C) contains a phosphate compound (c3), its content is 500 ppm or less in terms of phosphate root equivalent. If the phosphate compound content exceeds 500 ppm in terms of phosphate root equivalent, the recyclability deteriorates. The phosphate compound content is preferably 300 ppm or less in terms of phosphate root equivalent, more preferably 200 ppm or less, and may also be 150 ppm or less or 100 ppm or less. Furthermore, the phosphate compound content is preferably 10 ppm or more in terms of phosphate root equivalent, and more preferably 20 ppm or more. When the phosphate compound content is 10 ppm or more, the color of the recovered composition tends to be good. 【0035】 The phosphate compound (C3) is not particularly limited, and various acids such as phosphoric acid and phosphorous acid, or their salts, can be used. The phosphate may be included in the form of a first phosphate, second phosphate, or third phosphate, but the first phosphate is preferred. The cation species is also not particularly limited, but alkali metal salts are preferred. Among these, sodium dihydrogen phosphate and potassium dihydrogen phosphate are preferred. 【0036】 The EVOH resin composition layer (C) may preferably contain a thermoplastic resin (c4) for the purpose of improving the recyclability and flexural resistance of the multilayer film of the present invention. Normally, when the EVOH resin composition layer contains a thermoplastic resin (c4), the appearance of the multilayer film tends to deteriorate. However, because the EVOH resin composition layer (C) contains a hydrophobic plasticizer (c2), the recyclability and flexural resistance of the multilayer film can be improved without deterioration of appearance. In other words, when the EVOH resin composition layer (C) contains a thermoplastic resin (c4), the effect of improving appearance by the hydrophobic plasticizer (c2) tends to be more pronounced. When the EVOH resin composition layer (C) contains a thermoplastic resin (c4), the mass ratio of the thermoplastic resin (c4) to the EVOH resin (c1) (c4 / c1) is 10 / 90 or more and 40 / 60 or less. The mass ratio (c4 / c1) is preferably 15 / 85 or more and 35 / 65 or less, and more preferably 20 / 80 or more and 30 / 70 or less. When the mass ratio (c4 / c1) is within the above range, the recyclability and flexibility of the multilayer film tend to be good. 【0037】 The thermoplastic resin (c4) is not particularly limited as long as it is a thermoplastic resin different from EVOH resin (c1) and nylon 6, but it is preferably made up of at least one selected from the group consisting of acid-modified polyolefin, EVOH resin with an ethylene unit content of more than 60 mol%, nylon 6 / 12, nylon 6 / 66, and nylon 6 / 66 / 12, and more preferably at least one selected from these groups. 【0038】 When the thermoplastic resin (c4) contains an acid-modified polyolefin, the recyclability and flexural resistance of the multilayer film of the present invention tend to improve. When the thermoplastic resin (c4) contains an acid-modified polyolefin, from the viewpoint of further improving recyclability, it is preferable that the thermoplastic resin (c4) contains both an acid-modified polyolefin and an unmodified polyolefin, and more preferably both an acid-modified polyolefin and an unmodified polyolefin. 【0039】 As the unmodified polyolefin, the same polyolefin resin as that contained in the PO layer (A) can be used, and among these, LLDPE or ethylene α-olefin copolymer is preferred, ethylene α-olefin copolymer is more preferred, and ethylene-propylene copolymer is even more preferred. Furthermore, as the acid-modified polyolefin, an acid-modified polyolefin containing a carboxyl group or its anhydride obtained by chemically bonding an ethylenically unsaturated carboxylic acid or its anhydride (e.g., addition reaction, graft reaction, copolymerization, etc.) can be suitably used, and maleic anhydride-modified polyolefin is more preferred. As the acid-modified polyolefin into which the acid-modifying group is introduced, the same as the unmodified polyolefin described above can be suitably used. Among these, as the acid-modified polyolefin containing the carboxyl group or its anhydride, maleic anhydride-modified ethylene-α-olefin copolymer is preferred, and maleic anhydride-modified ethylene-propylene copolymer is more preferred. 【0040】 When the thermoplastic resin (c4) contains EVOH with an ethylene unit content exceeding 60 mol%, the recyclability and flexural resistance of the multilayer film of the present invention tend to improve. When the thermoplastic resin (c4) contains EVOH with an ethylene unit content exceeding 60 mol%, it is preferable that the thermoplastic resin (c4) is EVOH with an ethylene unit content exceeding 60 mol%. A preferred embodiment of EVOH with an ethylene unit content exceeding 60 mol% is the same as that of EVOH resin (c1), except for the ethylene unit content. The ethylene unit content of EVOH with an ethylene unit content exceeding 60 mol% is preferably 65 mol% to 90 mol%, and more preferably 70 mol% to 85 mol%. When the ethylene unit content of EVOH with an ethylene unit content exceeding 60 mol% is within the above range, the recyclability and flexural resistance of the multilayer film tend to be good. 【0041】 When the thermoplastic resin (c4) contains at least one selected from the group consisting of nylon 6 / 12, nylon 6 / 66, and nylon 6 / 66 / 12, the flexibility tends to improve, while the hue of the recovered composition tends to deteriorate. When the thermoplastic resin (c4) contains at least one selected from the group consisting of nylon 6 / 12, nylon 6 / 66, and nylon 6 / 66 / 12, it is preferable that the thermoplastic resin (c4) is at least one selected from the group consisting of nylon 6 / 12, nylon 6 / 66, and nylon 6 / 66 / 12. However, if the thermoplastic resin (c4) is nylon 6, it is undesirable because the recyclability of the multilayer film of the present invention deteriorates. 【0042】 The EVOH resin composition layer (C) may contain other components, such as carboxylic acid compounds, boron compounds, alkali metal salts, alkaline earth metal salts, blocking inhibitors, processing aids, stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, colorants, fillers, drying agents, crosslinking agents, and reinforcing agents for various fibers, as long as they do not hinder the effects of the present invention. The EVOH resin composition layer (C) may also contain a nonionic surfactant different from the hydrophobic plasticizer (c2), but it is preferable that it does not contain one. Furthermore, if the hydrophobic plasticizer (c2) is a nonionic surfactant, it is preferable from the viewpoint of improving the appearance that the EVOH resin composition layer (C) contains at least 0.05% by mass or more of such nonionic surfactant (hydrophobic plasticizer (c2)). 【0043】 If the EVOH resin composition layer (C) contains a carboxylic acid compound, discoloration during melt molding tends to be prevented. The carboxylic acid compound contained in the EVOH resin composition layer (C) may be a monocarboxylic acid, a polycarboxylic acid, or a combination thereof. The carboxylic acid compound contained in the EVOH resin composition layer (C) may be an ion, and such carboxylic acid ions may form salts with metal ions. Aliphatic carboxylic acids are preferably used as the carboxylic acid compound, and acetic acid is particularly preferably used. 【0044】 When the EVOH resin composition layer (C) contains a boron compound, torque fluctuations during heating and melting tend to be suppressed. The boron compound is not particularly limited and includes boric acids, boric acid esters, borate salts, boron hydride compounds, etc. Specifically, examples of boric acids include orthoboric acid, metaboric acid, and tetraboric acid; examples of boric acid esters include triethyl borate and trimethyl borate; and examples of borate salts include alkali metal salts of the above-mentioned boric acids, alkaline earth metal salts, and borax. Among these compounds, orthoboric acid (hereinafter sometimes simply referred to as boric acid) is preferred. When the EVOH resin composition layer (C) contains a boron compound, the content of the boron compound is preferably 20 to 2000 ppm in terms of boron element. When the content of the boron compound is 20 ppm or more, torque fluctuations during heating and melting tend to be suppressed, and more preferably 50 ppm or more. On the other hand, when the boron compound content is 2000 ppm or less, the moldability tends to be good, and more preferably 1000 ppm or less. 【0045】 When the EVOH resin composition layer (C) contains an alkali metal salt, the interlayer adhesion between the EVOH resin composition layer (C) and the adhesive resin layer (B) in the multilayer film of the present invention tends to be good. The cation species of the alkali metal salt is not particularly limited, but sodium salts or potassium salts are preferred. The anionic species of the alkali metal salt is also not particularly limited. It can be added as a carboxylate, carbonate, bicarbonate, phosphate, hydrogen phosphate, borate, hydroxide, etc. When the EVOH resin composition layer (C) contains an alkali metal salt, the alkali metal salt content is preferably 10 to 500 ppm in terms of metal element. More preferably, the alkali metal salt content is 50 ppm or more. On the other hand, when the alkali metal salt content is 500 ppm or less, the melt stability tends to be good, and more preferably, it is 300 ppm or less. 【0046】 When the EVOH resin composition layer (C) contains an alkaline earth metal salt, the degradation of the resin and the generation of degraded products such as gel during repeated melt molding tend to be suppressed. The cation species of the alkaline earth metal salt is not particularly limited, but magnesium salts or calcium salts are preferred. The anionic species of the alkaline earth metal salt is also not particularly limited. It can be added as a carboxylate, carbonate, bicarbonate, phosphate, hydrogen phosphate, borate, hydroxide, etc. 【0047】 As blocking inhibitors, inorganic oxides, inorganic nitrides, and inorganic oxidized nitrides selected from silicon, aluminum, magnesium, zirconium, cerium, tungsten, and molybdenum are used. Among these, silicon oxide is preferred due to its availability. 【0048】 Examples of processing aids include fluorine-based processing aids such as Arkema's Kynar™ and 3M's Dynamer™. When the EVOH resin composition layer (C) contains a processing aid, it tends to prevent the adhesion of EVOH degradation products to the EVOH resin composition layer (C) inside the extruder and die during multilayer film molding. 【0049】 Examples of stabilizers for improving melt stability include hydrotalcite compounds, hindered phenol-based and hindered amine-based heat stabilizers, and metal salts of higher aliphatic carboxylic acids (e.g., calcium stearate, magnesium stearate, etc.). When the EVOH resin composition layer (C) contains a stabilizer, its content is preferably 0.001 to 1% by mass. 【0050】 Examples of antioxidants include 2,5-di-t-butyl-hydroquinone, 2,6-di-t-butyl-p-cresol, 4,4'-thiobis-(6-t-butylphenol), 2,2'-methylene-bis-(4-methyl-6-t-butylphenol), octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, and 4,4'-thiobis-(6-t-butylphenol). 【0051】 Examples of UV absorbers include ethylene-2-cyano-3',3'-diphenyl acrylate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone. 【0052】 Examples of desiccants include sodium phosphate (Na3PO4), disodium hydrogen phosphate (Na2HPO4), sodium dihydrogen phosphate (NaH2PO4), sodium polyphosphate, lithium phosphate, dilithium hydrogen phosphate, lithium dihydrogen phosphate, lithium polyphosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, potassium polyphosphate, calcium phosphate (Ca3(PO4)2), calcium hydrogen phosphate (CaHPO4), calcium dihydrogen phosphate (Ca(H2PO4)2), calcium polyphosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and ammonium polyphosphate. Here, polyphosphates include diphosphates (pyrophosphates) and triphosphates (tripolyphosphates). Of these phosphates, anhydrous phosphates that do not contain crystal water are preferred. However, if the weight of the above desiccant contained in the EVOH resin composition layer (C) exceeds 500 ppm, the thermal stability of the EVOH resin composition layer (C) deteriorates, and the recyclability of the multilayer film of the present invention deteriorates. 【0053】 Examples of lubricants include ethylenebisstearamide and butyl stearate. 【0054】 Examples of colorants include carbon black, phthalocyanine, quinacridone, indoline, azo pigments, and red iron oxide. 【0055】 Examples of fillers include fiberglass, asbestos, ballastite, and calcium silicate. 【0056】 The proportion of EVOH resin (c1) and hydrophobic plasticizer (c2) in the EVOH resin composition layer (C) is preferably 65% ​​by mass or more, and more preferably 70% by mass or more, 80% by mass or more, 90% by mass or more, and 95% by mass or more. The EVOH resin composition layer (C) may consist substantially of only EVOH resin (c1) and hydrophobic plasticizer (c2). Furthermore, if the EVOH resin composition layer (C) contains a thermoplastic resin (c4), the proportion of EVOH resin (c1), hydrophobic plasticizer (c2), and thermoplastic resin (c4) in the EVOH resin composition layer (C) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may also be 98% by mass or more, or 99% by mass or more. The EVOH resin composition layer (C) may consist substantially only of EVOH resin (c1), hydrophobic plasticizer (c2), and thermoplastic resin (c4). 【0057】 The means for forming the resin composition of the EVOH resin composition layer (C) are not particularly limited, and for example, it can be produced by mixing or kneading the EVOH resin (c1) with a hydrophobic plasticizer (c2) under molten conditions. When producing the resin composition, in the multilayer film manufacturing method described later, the EVOH resin composition layer (C) may be produced by dry blending the EVOH resin (c1) and the hydrophobic plasticizer (c2) when forming the film, or the EVOH resin (C) and the hydrophobic plasticizer (c2) may be dry blended and then melt-kneaded to produce resin composition pellets in advance. If the EVOH resin composition layer (C) contains a thermoplastic resin (c4), it can be dry blended simultaneously with the EVOH resin (c1) and the hydrophobic plasticizer (c2). Furthermore, if the EVOH resin composition layer (C) contains a phosphate compound (c3) and other components, they may be dry blended simultaneously with the EVOH resin (c1) and the hydrophobic plasticizer (c2), or they may be included in the EVOH resin (c1) beforehand. Methods for pre-incorporating the phosphate compound (c3) and other components into the EVOH resin (c1) include immersing the EVOH resin (c1) in a solution containing the phosphate compound (c3) and other components, adding such a solution to the EVOH resin (c1), and dry-blending and melt-kneading various additives. From the viewpoint of improving the adhesive strength of the resulting multilayer film, it is preferable to manufacture the EVOH resin composition layer (C) by dry-blending each component (without pre-producing resin composition pellets). Mixing or kneading under melting conditions can be carried out using known mixing or kneading equipment such as a kneader-ruder, extruder, mixing roll, or Banbury mixer. The temperature during melt-kneading is usually 110 to 300°C. 【0058】 The thickness of each EVOH resin composition layer (C) is preferably 1 μm or more, and more preferably 2 μm or more. Furthermore, the thickness of each EVOH resin composition layer (C) is preferably 30 μm or less, and more preferably 25 μm or less. When the thickness of each EVOH resin composition layer (C) is within the above range, the gas barrier properties of the multilayer film tend to be stable and the flexibility is good. In addition, the total thickness of all layers of the EVOH resin composition layer (C) constituting the multilayer film of the present invention is preferably 1 μm or more and 30 μm or less. 【0059】 The ratio of the thickness of the EVOH resin composition layer (C) to the total thickness of the multilayer film of the present invention is 7.5% or less, preferably 6.5% or less, and more preferably 5% or less. If the thickness ratio exceeds 7.5%, appearance defects in the multilayer film are less likely to occur, but the flexibility and recyclability deteriorate. The thickness ratio is preferably 1% or more, and more preferably 2% or more. Furthermore, the thickness ratio is preferably 6.5% or less, and more preferably 5% or less. Note that if the thickness ratio of the EVOH resin composition layer (C) is less than 1%, the thickness uniformity of the EVOH resin composition layer (C) may be insufficient. 【0060】 (Adhesive resin layer (B)) The multilayer film of the present invention, by including an adhesive resin layer (B), exhibits good adhesion between the PO layer (A) and the EVOH resin composition layer (C), and tends to improve flexibility. Furthermore, the adhesive resin layer (B) may function as a compatibilizer for the PO layer (A) and the EVOH resin composition layer (C), potentially improving recyclability. The proportion of adhesive resin contained in the adhesive resin layer (B) is preferably 5% by mass or more, more preferably 30% by mass or more, even more preferably 70% by mass or more, particularly preferably 95% by mass or more, and may also be 99% by mass or more, or even 100% by mass. 【0061】 Examples of adhesive resins used in the adhesive resin layer (B) include modified olefin polymers containing carboxyl groups, obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to an olefin polymer by addition reaction or graft reaction. Examples of unsaturated carboxylic acids or their anhydrides include maleic acid, maleic anhydride, fumaric acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, citraconic acid, and hexahydrophthalic anhydride, among which maleic anhydride is preferably used. Specifically, one or more mixtures selected from maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft-modified ethylene-vinyl acetate copolymer, etc., are preferred. 【0062】 The adhesive properties of the adhesive resin layer (B) may be improved by mixing rubber / elastomer components such as polyisobutylene and ethylene-propylene rubber, or by mixing a polyolefin resin different from the polyolefin resin that forms the base of the adhesive resin. 【0063】 The thickness of each layer of the adhesive resin layer (B) is preferably 1 μm or more, and more preferably 2 μm or more. Furthermore, the thickness of each layer of the adhesive resin layer (B) is preferably 20 μm or less, and more preferably 15 μm or less. When the thickness of each layer of the adhesive resin layer (B) is within the above range, the interlayer adhesion between the EVOH resin composition layer (C) and the adhesive resin layer (B) tends to be good. In addition, the total thickness of all layers of the adhesive resin layer (B) constituting the multilayer film of the present invention is preferably 2 μm or more and 40 μm or less. 【0064】 The ratio of the thickness of the adhesive resin layer (B) to the total thickness of the multilayer film of the present invention is preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more. Furthermore, the ratio of the thickness of the adhesive resin layer (B) is preferably 15% or less, and more preferably 10% or less. 【0065】 (Multilayer film) The multilayer film of the present invention is not particularly limited as long as it has a layer structure in which a PO layer (A), an adhesive resin layer (B), and an EVOH resin composition layer (C) are laminated in this order. Each layer may be laminated directly or laminated via other layers, but from the viewpoint of preventing delamination between layers, it is preferable that the PO layer (A), the adhesive resin layer (B), and the EVOH resin composition layer (C) are directly laminated in this order. 【0066】 The multilayer film of the present invention may include a layer (D) made of a thermoplastic resin other than the PO layer (A), the adhesive resin layer (B), and the EVOH resin composition layer (C), and a recovery layer (R) made of a recovery composition described later. As the thermoplastic resin constituting the thermoplastic resin layer (D), it is preferable to use a thermoplastic resin with a melting point of less than 210°C from the viewpoint of suppressing deterioration of the recyclability of the multilayer film of the present invention. The thermoplastic resin with a melting point of less than 210°C is not particularly limited and examples include polystyrene resins, acrylic resins, vinyl ester resins, polyurethane resins, polycarbonate resins, etc. If the multilayer film of the present invention includes a layer (D) made of a polyamide resin such as nylon or a thermoplastic resin with a melting point exceeding 210°C such as polyester, it deteriorates the recyclability of the multilayer film of the present invention and is therefore undesirable. Furthermore, when the multilayer film of the present invention contains a polyamide resin as a thermoplastic resin layer (D), the proportion of polyamide resin in the recovered composition obtained by recovering the multilayer film of the present invention increases, which affects recyclability. However, if a small amount of a specific polyamide resin is included in the EVOH resin composition layer (C), the impact on recyclability is small, and therefore, as described above, this may be preferable from the viewpoint of improving flexibility. 【0067】 The layer structure of the multilayer film of the present invention is not particularly limited as long as it has a layer structure in which a PO layer (A), an adhesive resin layer (B), and an EVOH resin composition layer (C) are laminated in this order, but the following are examples. In the following examples, the PO layer (A) is represented as A, the adhesive resin layer (B) as B, the EVOH resin composition layer (C) as C, the thermoplastic resin layer (D) as D, and direct lamination is represented by " / ". 3 layers: A / B / C 5 layers: A / B / C / B / A, A / B / C / B / D 6 layers: A / B / C / B / D / A, D / A / B / C / B / A, A / D / B / C / B / D, D / A / B / C / B / D 7 layers: A / D / B / C / B / D / A, A / D / B / C / B / A / D, D / A / B / C / B / A / D, A / B / C / B / C / B / A 9 layers: A / D / B / C / B / C / B / D / A, A / D / B / C / B / C / B / A / D, D / A / B / C / B / C / B / A / D, A / B / C / B / D / B / C / B / A, D / B / C / B / D / B / C / B / A Among these, a multilayer film having an A / B / C / B / A layer configuration is preferred. The recovery layer (R) is a layer mainly composed of polyolefin resin, and may be used instead of the PO layer (A), or it may be used by laminating it directly onto the PO layer (A). When the multilayer film of the present invention has multiple layers of PO layer (A), adhesive resin layer (B), or EVOH resin composition layer (C), each layer may be the same or different. 【0068】 From the viewpoint of the heat-sealability of the PO layer (A), the total thickness of the multilayer film of the present invention is preferably 20 μm or more, and more preferably 30 μm or more. Furthermore, from the viewpoint of flexibility, the total thickness of the multilayer film of the present invention is less than 400 μm, preferably 300 μm or less, and may also be 250 μm or less, 200 μm or less, or 150 μm or less. Note that in the case of a multilayer structure with a total layer thickness of 400 μm or more, appearance defects tend to occur less frequently. Therefore, the problem of appearance defects in the present invention is significantly reduced by setting the total thickness to less than 400 μm and the ratio of the thickness of the EVOH resin composition layer (C) to the total thickness of the multilayer film to 7.5% or less. 【0069】 The adhesive strength between the EVOH resin composition layer (C) and the adhesive resin layer (B) of the multilayer film of the present invention, under an atmosphere of 23°C and 50% RH, is preferably 1.0 N / 15 mm or more, more preferably 2.0 N / 15 mm or more, and even more preferably 3.0 N / 15 mm or more. The adhesive strength of the multilayer film of the present invention can be increased by dry blending each component when forming the EVOH resin composition layer (C) (without producing resin composition pellets in advance). The adhesive strength of the multilayer film of the present invention can be measured by the method described in the examples. 【0070】 Examples of methods for manufacturing the multilayer film of the present invention include co-extrusion molding, extrusion lamination, and co-injection molding. Examples of co-extrusion molding methods include co-extrusion lamination, co-extrusion sheet molding, co-extrusion inflation molding, and co-extrusion blow molding. 【0071】 Furthermore, other films may be laminated onto the multilayer film of the present invention by dry lamination or extrusion lamination. 【0072】 The resulting multilayer film may be subjected to further secondary processing such as thermoforming methods including drawing, roll stretching, pantograph stretching, inflation stretching, or blow molding. 【0073】 It is preferable to reuse the recovered material (scrap) obtained by collecting edges and defective products generated during the manufacture of the multilayer film of the present invention. Thus, regarding the recovery of the multilayer film, off-spec products generated during manufacturing may be recovered, but it is a preferred embodiment to recover multilayer film that has been distributed to the market. A method for producing a recovery composition by crushing and then melt-molding the recovered multilayer film of the present invention, and a recovery composition containing the recovered multilayer film of the present invention are also preferred embodiments of the present invention. 【0074】 When recovering the multilayer film of the present invention, first, the recovered multilayer film of the present invention is crushed. The crushed recovered material may be melt-molded as is to obtain a recovered composition, or it may be melt-molded together with other components as needed to obtain a recovered composition. Examples of components to be added to the recovered material include polyolefin resins used in the PO layer (A). When melt-molding the recovered multilayer film of the present invention, known recovery aids may be added as needed. The crushed recovered material may be directly used in the manufacture of molded products such as multilayer structures, or the crushed recovered material may be melt-molded to obtain pellets made of the recovered composition, and then these pellets may be used in the manufacture of molded products. Possible melt-molding methods for the recovered material include pellet molding using a single-screw or twin-screw extruder, cast molding, inflation molding, blow molding, compression molding, injection molding, and melt spinning. The melting temperature varies depending on the melting point of the copolymer, but is preferably around 150 to 270°C. As described above, the recovered composition may contain unused polyolefin resins, but the content of the recovered material in the recovered composition is preferably 5% by mass or more. The obtained recovered composition is preferably used as the recovered layer (R) of the multilayer film. 【0075】 In the recovered composition thus obtained, the mass ratio of EVOH resin (c1) to polyolefin resin [EVOH resin (c1) / polyolefin resin] is preferably 0.05 / 99.95 to 7.5 / 92.5. 【0076】 Food packaging materials, beverage packaging materials, pharmaceutical packaging materials, cosmetic packaging materials, or agricultural materials using the multilayer film of the present invention are preferred embodiments of the present invention. 【0077】 The aforementioned packaging materials, such as food packaging materials, beverage packaging materials, pharmaceutical packaging materials, and cosmetic packaging materials, may also be packaging bodies formed by filling such packaging materials with contents. Such packaging bodies are useful because they can prevent the deterioration of the flavor of the contents due to oxygen. Examples of contents that can be filled include, but are not limited to, wine and fruit juice for beverages; fruits, nuts, vegetables, meat products, baby food, coffee, jam, mayonnaise, ketchup, edible oil, dressings, sauces, preserved foods, dairy products, etc. for foods; and pharmaceuticals, cosmetics, and contents that are prone to deterioration in the presence of oxygen. [Examples] 【0078】 The present invention will be described in more detail below using examples, but the present invention is not limited in any way by these examples. 【0079】 <Materials used in the examples and comparative examples> (EVOH resin (c1) (partially containing phosphate compounds (c3) is used)) c1-1: EVOH pellets, ethylene unit content 48 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 6.4 g / 10 min, phosphorus content (phosphate equivalent) 50 ppm c1-2: EVOH pellets, ethylene unit content 38 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 1.7 g / 10 min, phosphorus content (phosphate equivalent) 50 ppm c1-3: EVOH pellets, ethylene unit content 48 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 6.4 g / 10 min, phosphorus content (phosphate equivalent) 25 ppm c1-4: EVOH pellets, ethylene unit content 48 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 6.4 g / 10 min, phosphorus content (phosphate equivalent) 300 ppm c1-5: EVOH pellets, ethylene unit content 48 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 6.4 g / 10 min, phosphorus content (phosphate equivalent) 0 ppm c1-6: EVOH pellets, ethylene unit content 27 mol%, degree of saponification 99.9 mol%, MFR (210℃, 2.16 kg load) 4.5 g / 10 min, phosphorus content (phosphate equivalent) 50 ppm c1-7: EVOH pellets, ethylene unit content 44 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 5.7 g / 10 min, phosphorus content (phosphate equivalent) 50 ppm c1-8: EVOH pellets, ethylene unit content 29 mol%, degree of saponification 99.9 mol%, MFR (210℃, 2.16 kg load) 3.8 g / 10 min, phosphorus content (phosphate equivalent) 50 ppm c1-9: EVOH pellets, ethylene unit content 48 mol%, degree of saponification 99.9 mol%, MFR (190℃, 2.16 kg load) 6.4 g / 10 min, phosphorus content (phosphate equivalent) 600 ppm The phosphoric acid content of EVOH resin (c1) was measured according to the method described in evaluation method (1) below. 【0080】 (Hydrophobic plasticizer (c2)) GMS: Glycerin Monostearate GML: Glycerin monolaurate TGML: Tetraglycerin monolaurate DEP: Diethylphthalate DGL: Diglycerin Laurate GTS: Tetraglycerin Stearate (Hydrophilic plasticizer (c2')) GLR: Glycerin 【0081】 (Thermoplastic resin (c4)) c4-1: UBE Nylon (registered trademark) 7034 manufactured by Ube Industries, Ltd. (PA6 / 12 copolymer, melting point 201℃, relative viscosity (96% sulfuric acid, polymer concentration 1.0 wt%) 3.86) c4-2: UBE Industries, Ltd.'s "UBE Nylon (Registered Trademark) 6434" (PA6 / 66 / 12 copolymer, melting point 188°C, relative viscosity (96% sulfuric acid, polymer concentration 1.0 wt%) 4.05) c4-3: Mitsui Chemicals, Inc. "Tafmer (registered trademark) P0280" (ethylene-propylene copolymer, MFR: 5.4g / 10min (230℃, load 2160g)) c4-4: Mitsui Chemicals, Inc. "Tafmer (registered trademark) MP0620" (maleic anhydride-modified ethylene-propylene copolymer, manufactured by Mitsui Chemicals, Inc., MFR: 0.3g / 10min (230℃, load 2160g)) c4-5: ExxonMobil "Exceed (registered trademark) 1018" (LLDPE, MFR: 1.0g / 10min (190℃, load 2160g)) c4-6: "Mersen (registered trademark) H-6051" manufactured by Tosoh Corporation (ethylene-vinyl acetate copolymer saponified product, ethylene unit content 89 mol%, degree of saponification 97 mol%, MFR (190℃, 2.16 kg load) 5.5 g / 10 min) c4-7: UBE Nylon (registered trademark) 1030 manufactured by Ube Industries, Ltd. (PA6, melting point 220℃, relative viscosity (96% sulfuric acid, polymer concentration 1.0 wt%) 4.08) 【0082】 (Polyolefin resin) mLLDPE1: "Evolu (registered trademark) SP1020" (linear low-density polyethylene polymerized using a metallocene catalyst, manufactured by Prime Polymer Co., Ltd., density 0.909 g / cm³) 3 ) 【0083】 (adhesive resin) MAH-PE1: "Admer (registered trademark) NF498E" (maleic anhydride-modified polyethylene, manufactured by Mitsui Chemicals, Inc.) 【0084】 <Evaluation Method> (1) Determination of phosphate compounds 0.5 g of EVOH resin (c1) used in the examples and comparative examples was placed in a Teflon® pressure vessel, and 5 mL of concentrated nitric acid was added to decompose it at room temperature for 30 minutes. After 30 minutes, the lid was closed, and decomposition was carried out by heating at 150°C for 10 minutes, followed by 180°C for 5 minutes, using a wet decomposition apparatus (Actac's "MWS-2"), and then cooled to room temperature. This treated solution was transferred to a 50 mL volumetric flask (TPX) and diluted with pure water. Elemental analysis of this solution was performed using an ICP emission spectrometer (PerkinElmer's "OPTIMA4300DV") to determine the phosphorus atom equivalent amount of the phosphate compound. (2) Measurement of the thickness of each layer of a multilayer film The multilayer films prepared in the examples and comparative examples were cut into 2 cm squares, cross-sections were prepared using a small rotary microtome PR-50 manufactured by Yamato Koki Kogyo Co., Ltd., and the thickness of each layer was measured using an optical microscope (model: ECLIPSE LV100ND) manufactured by Nikon Instec Corporation. 【0085】 (3) Resin pressure stability The resin pressure fluctuations of the extruder for the EVOH resin composition layer (C) were measured during continuous multilayer film molding for 1 hour under the conditions described in the Examples and Comparative Examples, and evaluated according to the following criteria. A score of A or B indicated excellent resin stability. Note that unstable resin pressure can lead to unstable discharge volume and thickness of the EVOH resin composition layer (C), potentially resulting in variations in quality. A: Less than ±5% B: ±5% or more and less than ±10% C: ±10% or more and less than ±20% D: ±20% or more 【0086】 (4) Evaluation of the appearance of multilayer films The multilayer films obtained in the examples and comparative examples were cut from the center of the width direction into 10 cm squares, and their appearance was visually observed and evaluated according to the following criteria. A rating of A or B was considered to indicate excellent appearance. The irregularities described in the following criteria refer to minute irregularities (interface irregularities) that occur at the interface between the EVOH resin composition layer (C) and the adhesive resin layer (B), and can be visually observed as streaks or irregularities resembling the surface of an orange peel (orange peel). A: No inconsistencies were observed. B: Some inconsistencies were observed. C: Significant unevenness was observed throughout the film. D: The entire film became cloudy. 【0087】 (5) Flexural resistance of multilayer films The multilayer films obtained in the examples and comparative examples were conditioned at 23°C / 50%RH, and then their flexibility was measured using a Gelboflex tester (BE-1005, manufactured by Tester Sangyo Co., Ltd.). Specifically, a 12-inch x 8-inch film was first formed into a 3.5-inch diameter cylinder. Both ends were gripped, with an initial gripping distance of 7 inches, a gripping distance of 1 inch at maximum bending, a twist of 440 degrees in the first 3.5 inches of the stroke, and then a reciprocating motion consisting of a straight horizontal movement for the next 2.5 inches was performed at a speed of 40 times / minute, and the presence or absence of pinholes after 1000 reciprocating motions was evaluated. To check the number of pinholes, the multilayer film after the bending test was placed on white paper, red ink was applied to the entire surface of the multilayer film, and then the multilayer film was peeled off. The number of ink dots observed on the white paper was counted as the number of pinholes and evaluated according to the following criteria. A rating of A or B indicated excellent flexibility. A: No pinholes B: Number of pinholes: 1 to 10 C: More than 10 pinholes 【0088】 (6) Testing of recovered composition (6-1) Recyclability (fisheye) Using the pulverized material (recovered material) obtained by crushing the multilayer films obtained in the examples and comparative examples, a single-layer film with a thickness of 20 μm was manufactured using a 20 mmφ extruder, and the film was wound onto a 3-inch diameter paper tube to produce a single-layer film roll. <Conditions for producing single-layer films> Equipment: 20mmφ single-screw extruder (Toyo Seiki Seisakusho Lab Plast Mill 15C300) L / D:20 Screw: Full Flight Die: 300mm coat hanger die Extrusion temperature (°C): C1=200, C2~C5=230, Die=230 Screen: 50 / 100 / 50 Cooling roll temperature: 80℃ Pickup speed: 3.0~3.5m / min Film thickness: 20μm The number of fisheyes (number / m²) observed per unit area of ​​the obtained single-layer film 30 minutes after the start of the single-layer film deposition process. 2 The values ​​were measured using a fisheye counter (model: ZD / AD1) manufactured by Frontier Systems Co., Ltd. A score of A, B, or C indicated excellent recyclability. A:500 pieces / m 2 less than B:500 pieces / m 2 More than 750 pieces / m 2 less than C:750 pieces / m 2 More than 1000 pieces / m 2 less than D:1000 pieces / m 2 More than 1500 pieces / m 2 less than E:1500 pieces / m 2 That's all. (6-2) Hue Furthermore, the hue of the end face of the obtained single-layer film roll was evaluated as follows. A: No yellowing was observed. B: Slight yellowing was observed. C: Significant yellowing was observed. 【0089】 (Example 1) 100 parts by mass of EVOHc1-1 pellets and 0.1 parts by mass of glycerin monostearate were dry-blended, and then melt-kneaded under the following conditions to prepare EVOH resin composition pellets. <Pellet production conditions> Equipment: 30mmφ twin-screw extruder manufactured by Toyo Seiki Seisakusho Co., Ltd. L / D: 45.5 Screw: Fully meshing in the same direction Extrusion temperature (°C): 230°C Rotation speed: 200 rpm Discharge amount: 20kg / hr 【0090】 The obtained EVOH resin composition pellets were used as the EVOH resin composition layer (C), mLLDPE1 as the PO layer (A), and MAH-PE1 as the adhesive resin layer (B). A multilayer film was prepared using a co-extrusion multilayer casting apparatus under the following conditions. During the preparation of the multilayer film, the resin pressure stability was evaluated according to the method described in evaluation method (2) above. The results are shown in Table 1. <Multilayer film production conditions> Layer configuration: ((A) / (B) / (C) / (B) / (A)=42.5μm / 5μm / 5μm / 5μm / 42.5μm) T-die: 300mm width, 3 types, 5 layers (manufactured by Plastics Engineering Laboratory Co., Ltd.) Cooling roll temperature: 80℃ Pickup speed: 1.5m / min (Polyolefin layer (A)) Extruder: 32mmφ extruder GT-32-A type (manufactured by Plastics Engineering Research Institute Co., Ltd.) Temperature conditions: Feed section / Compression section / Measuring section / Die = 170 / 220 / 220 / 220℃ (Adhesive resin layer (B)) Extruder: 25mmφ extruder P25-18-AC type (manufactured by Osaka Seiki Kogyo Co., Ltd.) Temperature conditions: Feed section / Compression section / Measuring section / Die = 170 / 220 / 220 / 220℃ (EVOH resin composition layer (C)) Extruder: 20mmφ extruder, laboratory type ME CO-EXT (manufactured by Toyo Seiki Seisakusho Co., Ltd.) Temperature conditions: Feed section / Compression section / Measuring section / Die = 170 / 220 / 220 / 220℃ 【0091】 (Examples 2-5, 12-22, Comparative Examples 1-5, 12-15) Except for changing the type and content of EVOH resin (c1), the type and content of hydrophobic plasticizer (c2), and the thickness ratio of the EVOH resin composition layer (C) and the PO layer (A) as shown in Tables 1 and 2, EVOH resin composition pellets and multilayer films were prepared and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2. 【0092】 (Example 6) EVOH resin composition pellets and multilayer films were prepared and evaluated in the same manner as in Example 1, except that 80 parts by mass of EVOHc1-1 pellets, 20 parts by mass of thermoplastic resin c4-1 pellets, and 1 part by mass of glycerin monostearate were dry-blended. The results are shown in Table 1. 【0093】 (Example 7, Example 11, Comparative Examples 6-8, Comparative Example 11) Except for changing the content of EVOH resin (c1), the type and content of thermoplastic resin (c4), and the content of hydrophobic plasticizer (c2) as shown in Tables 1 and 2, EVOH resin composition pellets and multilayer films were prepared and evaluated in the same manner as in Example 6. The results are shown in Tables 1 and 2. 【0094】 (Example 8) EVOH resin composition pellets and multilayer films were prepared and evaluated in the same manner as in Example 1, except that 80 parts by mass of EVOHc1-1 pellets, 16 parts by mass of thermoplastic resin c4-3 pellets, 4 parts by mass of thermoplastic resin c4-4 pellets, and 1 part by mass of glycerin monostearate were dry-blended. The results are shown in Table 1. 【0095】 (Examples 9 and 10, Comparative Examples 9 and 10) Except for changing the content of EVOH resin (c1), the type, mass ratio, and content of thermoplastic resin (c4), and the content of hydrophobic plasticizer (c2), EVOH resin composition pellets and multilayer films were prepared and evaluated in the same manner as in Example 8. The results are shown in Tables 1 and 2. 【0096】 [Table 1] 【0097】 [Table 2] 【0098】 A comparison of Examples 1-4 and Comparative Example 1 shows that the appearance of the multilayer film is improved by adding a hydrophobic plasticizer (c2). A comparison of Example 3 and Comparative Example 2 shows that recyclability deteriorates when the average ethylene unit content is less than 30 mol%, while good recyclability is observed when the average ethylene unit content exceeds 30 mol%. A comparison of Example 4 and Comparative Examples 3-4 shows that the resin pressure of the EVOH resin composition layer (C) becomes unstable when the amount of hydrophobic plasticizer is excessive. A comparison of Example 3 and Comparative Example 5 shows that the resin pressure of the EVOH resin composition layer (C) becomes unstable when a hydrophilic plasticizer is used. 【0099】 A comparison of Example 3 with Examples 6-7 shows that adding nylon 6 / 12 or nylon 6 / 6 / 12 to the EVOH resin composition layer (C) improves the flexural resistance of the multilayer film. A comparison of Examples 6-7 with Comparative Example 6 shows that adding nylon 6 to the EVOH resin composition layer (C) negatively affects the recyclability of the multilayer film. A comparison of Example 6 with Comparative Example 8 shows that an excessive amount of nylon 6 / 12 added to the EVOH resin composition layer (C) negatively affects the recyclability of the multilayer film. A comparison of Example 3 with Examples 8-11 shows that adding unmodified polyolefin resins, acid-modified polyolefin resins, or EVOH with an ethylene content exceeding 60 mol% to the EVOH resin composition layer (C) improves not only the flexural resistance but also the recyclability of the multilayer film. 【0100】 A comparison of Example 9 and Comparative Example 10 shows that if the amount of unmodified polyolefin resin and acid-modified polyolefin resin added to the EVOH resin composition layer (C) is excessive, a poor appearance (cloudiness) of the multilayer film occurs. A comparison of Examples 3 and 18 and Comparative Example 12 shows that if the thickness ratio of the EVOH resin composition layer (C) in the multilayer film exceeds 7.5%, the flexibility and recyclability of the multilayer film deteriorate, and it is more preferable to have a thickness of 5% or less. Furthermore, Comparative Examples 12, 13, and 14 show that if the thickness ratio of the EVOH resin composition layer (C) in the multilayer film exceeds 7.5%, a good appearance is obtained regardless of whether or not a hydrophobic plasticizer (c2) is added. Considering the results of Example 1 and Comparative Example 1, it can be said that in order to achieve good flexibility and recyclability of the multilayer film, the thickness ratio of the EVOH resin composition layer (C) in the multilayer film must be 7.5% or less, and the addition of a hydrophobic plasticizer (c2) is effective only when the thickness ratio is 7.5% or less. 【0101】 A comparison of Example 3 and Comparative Example 15 shows that when the content of the phosphate compound (c3) in the EVOH resin composition layer (C) exceeds 500 ppm, the recyclability (fisheye pattern) of the multilayer film deteriorates. A comparison of Example 3 and Example 21 shows that including the phosphate compound (c3) in the EVOH resin composition layer (C) is preferable in terms of the hue of the recovered composition. A comparison of Example 1 and Example 13, and a comparison of Example 3 and Example 14, shows that using an aliphatic ester as a hydrophobic plasticizer is preferable to using an aromatic ester because it provides a higher appearance improvement effect. A comparison of Example 22 and Comparative Example 2 shows that when the average value of the ethylene unit content of the EVOH resin (c1) is 30 mol% or more, the recyclability is good. 【0102】 (Example 23) A multilayer film was prepared and evaluated in the same manner as in Example 3, except that a dry blend of 100 parts by mass of EVOHc1-1 pellets and 1 part by mass of glycerin monostearate was used as the raw material for the EVOH resin composition layer (C) instead of EVOH resin composition pellets. The results are shown in Table 3. 【0103】 (Evaluation of adhesive strength) The adhesive strength between the EVOH resin composition layer (C) and the adhesive resin layer (B) in the multilayer films obtained in Example 3, Example 23, and Comparative Example 1 was measured under the following conditions. The multilayer films obtained in Example 3, Example 23, and Comparative Example 1 were conditioned for 7 days at 23°C and 50% RH, and then 15 mm × 200 mm strip-shaped test pieces were cut out. The T-type peel strength (gf / 15 mm) of the obtained test pieces was measured using a Shimadzu Autograph AGS-H type under the conditions of a chuck spacing of 50 mm and a tensile speed of 250 mm / min. Measurements were performed on five test pieces, and the average value was taken as the adhesive strength. The results are shown in Table 3. 【0104】 [Table 3] 【0105】 The adhesive strength of Example 3, a multilayer film made via melt-mixing and EVOH resin composition pellets, was 1.5 N / 15 mm, while the adhesive strength of Example 23, a multilayer film made using the dry blend directly as the raw material for the EVOH resin composition layer (C), was 4.6 N / 15 mm. This indicates that using the dry blend directly as the raw material for the EVOH resin composition layer (C) to produce a multilayer film results in improved adhesive strength compared to producing a multilayer film via an EVOH resin composition.

Claims

[Claim 1] A multilayer film having a layer structure in which a polyolefin layer (A), an adhesive resin layer (B), and an ethylene-vinyl alcohol copolymer resin composition layer (C) are laminated in this order, The ethylene-vinyl alcohol copolymer resin composition layer (C) comprises an ethylene-vinyl alcohol copolymer resin (c1) with an ethylene unit content of 20 mol% to 60 mol% and a degree of saponification of 90 mol% or more, and a hydrophobic plasticizer (c2). The ethylene-vinyl alcohol copolymer resin (c1) content in the ethylene-vinyl alcohol copolymer resin composition layer (C) is 60% by mass or more and 99.9% by mass or less. The average ethylene unit content of the ethylene-vinyl alcohol copolymer resin (c1) constituting the ethylene-vinyl alcohol copolymer resin composition layer (C) is 30 mol% or more and 60 mol% or less. The hydrophobic plasticizer (c2) content in the ethylene-vinyl alcohol copolymer resin composition layer (C) is 0.1% by mass or more and 3% by mass or less. The ethylene-vinyl alcohol copolymer resin composition layer (C) may further contain a phosphate compound (c3), and if the ethylene-vinyl alcohol copolymer resin composition layer (C) contains a phosphate compound (c3), its content is 500 ppm or less in terms of phosphate. The ethylene-vinyl alcohol copolymer resin composition layer (C) does not contain nylon 6. A multilayer film in which the thickness ratio of the ethylene-vinyl alcohol copolymer resin composition layer (C) to the total thickness of the multilayer film is 7.5% or less. [Claim 2] The multilayer film according to claim 1, wherein the hydrophobic plasticizer (c2) contained in the ethylene-vinyl alcohol copolymer resin composition layer (C) is an aliphatic ester. [Claim 3] The multilayer film according to claim 1 or 2, wherein the thickness ratio of the ethylene-vinyl alcohol copolymer resin composition layer (C) to the total thickness of the multilayer film is 5% or less. [Claim 4] A multilayer film according to any one of claims 1 to 3, wherein the content of the hydrophobic plasticizer (c2) in the ethylene-vinyl alcohol copolymer resin composition layer (C) is 0.6% by mass or more and 3% by mass or less. [Claim 5] A multilayer film according to any one of claims 1 to 4, wherein the ethylene-vinyl alcohol copolymer resin composition layer (C) contains a thermoplastic resin (c4) different from the ethylene-vinyl alcohol copolymer resin (c1), and the mass ratio (c4 / c1) of the thermoplastic resin (c4) to the ethylene-vinyl alcohol copolymer resin (c1) in the ethylene-vinyl alcohol copolymer resin composition layer (C) is 10 / 90 to 40 / 60. [Claim 6] The multilayer film according to claim 5, wherein the thermoplastic resin (c4) contains an acid-modified polyolefin. [Claim 7] The multilayer film according to claim 5, wherein the thermoplastic resin (c4) comprises an ethylene-vinyl alcohol copolymer resin having an ethylene unit content of more than 60 mol%. [Claim 8] The multilayer film according to claim 5, wherein the thermoplastic resin (c4) comprises at least one selected from the group consisting of nylon 6 / 12, nylon 6 / 66, and nylon 6 / 66 / 12. [Claim 9] The multilayer film according to any one of claims 1 to 8, wherein the polyolefin resin constituting the polyolefin layer (A) is at least one selected from the group consisting of low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and polypropylene. [Claim 10] A multilayer film according to any one of claims 1 to 9, wherein the polyolefin resin constituting the polyolefin layer (A) is a metallocene polyolefin polymerized using a metallocene catalyst. [Claim 11] Food packaging material, beverage packaging material, pharmaceutical packaging material, cosmetic packaging material, or agricultural material using the multilayer film described in any one of claims 1 to 10. [Claim 12] A recovery composition comprising the recovered multilayer film according to any one of claims 1 to 10. [Claim 13] A method for producing a recovered composition, comprising the step of melting and kneading the recovered multilayer film according to any one of claims 1 to 10.

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