Multilayer film, vapor-deposited multilayer film, multilayer structure, packaging material, recovery composition, and recycling method

Abstract

Provided are a multilayer film and the like that achieve both external appearance properties and interlayer adhesiveness. This multilayer film is a co-extruded multilayer film which has a layer (X) at the outermost layer and in which the layer (X), a layer (Y), and a layer (Z) are directly laminated in the stated order. The layer (X) contains, as the main component, an ethylene-vinyl alcohol copolymer (x) having an ethylene unit content of 20-59 mol% and a degree of saponification of 80 mol% or more. The layer (Y) contains, as the main component, an ethylene-vinylester copolymer or a saponified product (y1) thereof having an ethylene unit content of 60-99 mol% and a degree of saponification of 0-99.9 mol%. The layer (Z) contains a polypropylene (z) as the main component.

Description

Multilayer film, vapor-deposited multilayer film, multilayer structure, packaging material, recovered composition, and recycling method

[0001] The present invention relates to multilayer films, vapor-deposited multilayer films, multilayer structures, packaging materials, recovered compositions, and recycling methods.

[0002] Packaging materials for long-term storage of food and other products often require gas barrier properties, including oxygen barrier properties. By using packaging materials with high gas barrier properties, oxidative deterioration of food and other products due to oxygen intrusion, as well as microbial growth, can be suppressed. Widely used layers to improve gas barrier properties include metal foils and metal vapor-deposited layers such as aluminum, and inorganic oxide vapor-deposited layers such as silicon dioxide and aluminum oxide. On the other hand, resin layers with gas barrier properties such as vinyl alcohol polymers and polyvinylidene chloride are also widely used. Vinyl alcohol polymers have the characteristic of exhibiting gas barrier properties by crystallizing and increasing in density through hydrogen bonding between hydroxyl groups in the molecule. Among them, ethylene-vinyl alcohol copolymer (hereinafter also referred to as "EVOH") is suitable for melt molding due to its excellent thermal stability, and with the development of co-extrusion technology, co-extruded multilayer films having an EVOH layer are widely used as gas barrier packaging materials. Furthermore, it is widely known that the oxygen barrier and water vapor barrier can be improved by vapor deposition of aluminum onto the EVOH surface of a multilayer film having EVOH as its outermost layer. For example, Patent Document 1 describes a vapor-deposited multilayer film in which an EVOH layer, an adhesive resin layer, and a polyolefin layer are laminated in that order, and aluminum vapor deposition is applied to the co-extruded multilayer film.

[0003] International Publication No. 2021 / 261560

[0004] In co-extruded multilayer films having an EVOH layer on the surface, such as the co-extruded multilayer film described in Patent Document 1, acid-modified polyolefins are widely used as the adhesive resin layer for bonding the EVOH layer. However, such conventional co-extruded multilayer films may have problems such as poor appearance.

[0005] The present invention has been made based on these circumstances, and its objective is to provide a co-extruded multilayer film having a layer mainly composed of EVOH, which achieves both good appearance and interlayer adhesion, as well as a vapor-deposited multilayer film using such a multilayer film, a multilayer structure, a packaging material, a recovery composition, and a recycling method.

[0006] The above objective is to provide a co-extruded multilayer film having layer (X) as the outermost layer, in which layers (X), (Y), and (Z) are directly laminated in this order, wherein layer (X) mainly contains an ethylene-vinyl alcohol copolymer (x) having an ethylene unit content of 20 to 59 mol% and a degree of saponification of 80 mol% or more, and layer (Y) mainly contains an ethylene-vinyl ester copolymer or its saponified product (y1) having an ethylene unit content of 60 to 99 mol% and a degree of saponification of 0 to 99.9 mol%, and the ethylene-vinyl ester copolymer or its saponified product (y1) If the degree of saponification of (y1) is 1 to 99.9 mol%, layer (Y) contains 30 parts by mass or less of a tackifier (y2) per 100 parts by mass of ethylene-vinyl ester copolymer or its saponified product (y1), or does not contain a tackifier (y2); if the degree of saponification of the ethylene-vinyl ester copolymer or its saponified product (y1) is less than 1 mol%, layer (Y) contains 1 to 30 parts by mass of a tackifier (y2) per 100 parts by mass of ethylene-vinyl ester copolymer or its saponified product (y1), and layer (Z) is a multilayer film mainly composed of polypropylene (z); [2] A multilayer film of [1] in which polypropylene (z) is a random copolymer; [3] A multilayer film of [1] or [2] in which the average thickness is 300 μm or less and the average thickness of layer (X) is 30 μm or less; [4] A multilayer film of [1] or [2] in which the average thickness is 300 μm or less and the average thickness of layer (X) is less than 20 μm; [5] A multilayer film of any of [1] to [4] in which the tackifier (y2) is at least one selected from the group consisting of petroleum resin, terpene resin and rosin resin; [6] A multilayer film of any of [1] to [5] in which it is an unstretched film; [7] A multilayer film of any of [1] to [5] in which it is a stretched film stretched by 3 times or more and less than 12 times in at least one axial direction; A vapor-deposited multilayer film comprising one of the multilayer films of [8] [1] to [7] and an inorganic vapor-deposited layer (I) which is a metal vapor-deposited layer mainly composed of aluminum or an inorganic oxide vapor-deposited layer mainly composed of alumina or silica, laminated on the exposed surface side of layer (X);[9] A multilayer structure comprising a multilayer film of any of [1] to [7] or a vapor-deposited multilayer film of [8] and at least one layer (R) laminated on the multilayer film or vapor-deposited multilayer film, the layer mainly composed of a thermoplastic resin (r);

[10] A multilayer structure of [9] wherein the thermoplastic resin (r) is polypropylene;

[11] A multilayer structure of

[10] wherein the polypropylene content is 80% by mass or more;

[12] A packaging material having a multilayer film of any of [1] to [7], a vapor-deposited multilayer film of [8] or a multilayer structure of any of [9] to

[11] ;

[13] A recovered composition comprising recovered material of a multilayer film of any of [1] to [7], a vapor-deposited multilayer film of [8] or a multilayer structure of any of [9] to

[11] ;

[14] A recycling method comprising the steps of obtaining crushed material by crushing a multilayer film of any of [1] to [7], a vapor-deposited multilayer film of [8] or a multilayer structure of any of [9] to

[11] , and melt-molding a composition containing the crushed material; This is achieved by providing [something].

[0007] According to the present invention, it is possible to provide a co-extruded multilayer film having a layer mainly composed of EVOH, which achieves both good appearance and interlayer adhesion, as well as a vapor-deposited multilayer film using such a multilayer film, a multilayer structure, a packaging material, a recovered composition, and a recycling method. Here, "appearance" can be evaluated by observing the appearance of the multilayer film, particularly the streaking of the multilayer film, using an image quality measuring instrument, and can be specifically evaluated by the method described in the examples. Furthermore, "interlayer adhesion" refers to the adhesion between the layer mainly composed of EVOH and the layer directly laminated to this layer in the multilayer film, and can be specifically evaluated by the method described in the examples.

[0008] Embodiments of the present invention will be described below. In the following description, specific materials (compounds, etc.) that exhibit particular functions may be given as examples, but the present invention is not limited to embodiments using such materials. Furthermore, unless otherwise specified, the materials described may be used individually or in combination.

[0009] The term "outermost layer" is not limited to the layer present on the front side, distinguishing between the front and back. In other words, any layer with an exposed surface is the outermost layer. "Main component" refers to a component present in an amount of 50% by mass or more. The numerical range expressed as "A to B" includes A as the lower limit and B as the upper limit. In other words, "A to B" is equal to A or greater and B or less. The "average thickness" of each layer, unless otherwise specified, refers to the average value of the thickness measured at any five locations. "Polypropylene" refers to a homopolymer of propylene, a copolymer of 80 mol% or more of propylene and 20 mol% or less of α-olefin monomer, and a copolymer of 95 mol% or more of propylene and less than 5 mol% of a non-olefin monomer whose functional groups do not contain atoms other than carbon, oxygen, and hydrogen atoms. In this specification, when representing the layer structure, " / " indicates direct lamination, and " / / " indicates lamination directly or via an adhesive layer.

[0010] <Multilayer Film> The multilayer film of the present invention is a co-extruded multilayer film having layer (X) as the outermost layer, in which layers (X), (Y), and (Z) are directly laminated in this order, wherein layer (X) mainly contains an ethylene-vinyl alcohol copolymer (x) (hereinafter also referred to as "EVOH(x)") having an ethylene unit content of 20 to 59 mol% and a degree of saponification of 80 mol% or more, and layer (Y) contains an ethylene-vinyl ester copolymer or The material contains its saponified product (y1) (hereinafter also referred to as "polymer (y1)") as its main component, and when the degree of saponification of copolymer (y1) is 1 to 99.9 mol%, layer (Y) contains 30 parts by mass or less of a tackifier (y2) per 100 parts by mass of copolymer (y1), or does not contain a tackifier (y2), and when the degree of saponification of copolymer (y1) is less than 1 mol%, layer (Y) contains 1 to 30 parts by mass of a tackifier (y2) per 100 parts by mass of copolymer (y1), and layer (Z) contains polypropylene (z) as its main component.

[0011] The multilayer film of the present invention is a co-extruded multilayer film having a layer (X) mainly composed of EVOH(x), and achieves both good appearance and interlayer adhesion. The reason for this is not clear, but the following reason is speculated. In the case of conventional co-extruded multilayer films in which a layer mainly composed of EVOH and an adhesive resin layer are directly laminated and an acid-modified polyolefin is used as the adhesive resin, it is thought that excessive chemical bonding between EVOH and the acid-modified polyolefin that occurs during melt extrusion (esterification reaction between the hydroxyl group of EVOH and the acidic group of the acid-modified polyolefin) promotes localized crosslinking at the interface, resulting in poor appearance. In contrast, in the multilayer film of the present invention, a copolymer (y1) is used as the resin that adheres the layer (X) mainly composed of EVOH(x). In the case of a copolymer (y1) with a degree of saponification of 1 to 99.9 mol%, the copolymer (y1) has high compatibility with EVOH(x). In this case, the interlayers are bonded by the compatibility of EVOH(x) and copolymer (y1) at the interface during melt extrusion. On the other hand, in the case of copolymer (y1) with a degree of saponification of less than 1 mol%, the compatibility between EVOH(x) and copolymer (y1) is insufficient, but the interlayer adhesion can be improved by using a tackifier (y2). Thus, in the multilayer film of the present invention, the layer (X) containing EVOH(x) as the main component and the layer (Y) directly laminated to this layer (X) are bonded not by a chemical reaction but by utilizing the compatibility of the resin and the properties of the tackifier, resulting in a good appearance and high interlayer adhesion.

[0012] Furthermore, in the multilayer film of the present invention, the layer (X) containing EVOH(x) as the main component has few localized crosslinks and other phenomena, and a highly homogeneous layer (X) is formed, resulting in excellent gas barrier properties. Moreover, a vapor-deposited multilayer film in which an inorganic vapor-deposited layer (I) is laminated on the surface of such a layer (X) can also exhibit excellent gas barrier properties.

[0013] A multilayer film according to one embodiment of the present invention also exhibits excellent recyclability. Because polyolefins and EVOH do not mix well, when a conventional multilayer film having a polyolefin layer, an EVOH layer, and a layer containing maleic acid-modified polyolefin resin is melt-molded again and reused as a recycled molded body, thermal degradation during melt-molding can cause gelation, or degraded material can adhere to the screw in the extruder, etc., resulting in appearance defects such as fish eyes in the resulting molded body. In contrast, when a multilayer film, vapor-deposited multilayer film, multilayer structure, etc., according to one embodiment of the present invention is recycled, the occurrence of fish eyes and other defects in the resulting molded body is suppressed. Possible reasons for this include the fact that the copolymer (y1) and tackifier (y2) contribute as compatibilizers between EVOH (x) and polypropylene (z), and that, unlike the conventional adhesion mechanism reaction due to the chemical reaction (crosslinking reaction) between maleic acid-modified polyolefin and EVOH, the copolymer (y1) and EVOH (x) are bonded by compatibilization rather than a chemical reaction, so no crosslinking reaction occurs.

[0014] (Layer (X)) Layer (X) is the outermost layer on at least one side of the multilayer film. Layer (X) mainly contains EVOH(x) (ethylene-vinyl alcohol copolymer (x)) having an ethylene unit content of 20 to 59 mol% and a degree of saponification of 80 mol% or more.

[0015] EVOH(x) is a copolymer typically obtained by saponifying an ethylene-vinyl ester copolymer, which is obtained by polymerizing ethylene and a vinyl ester. Examples of vinyl esters include vinyl acetate, vinyl propionate, and vinyl pivalate, with vinyl acetate being preferred.

[0016] The lower limit of the ethylene unit content of EVOH(x) is 20 mol%, preferably 24 mol%, and may be 30 mol%, 35 mol%, or 40 mol%. Having an ethylene unit content of EVOH(x) above the above lower limit enhances compatibility with the copolymer (y1), thereby improving interlayer adhesion and recyclability. On the other hand, the upper limit of the ethylene unit content of EVOH(x) is 59 mol%, preferably 55 mol%, more preferably 50 mol%, even more preferably 45 mol%, and may be 40 mol%, 35 mol%, or 30 mol%. Having an ethylene unit content of EVOH(x) below the above upper limit enhances gas barrier properties. Furthermore, having an ethylene unit content of EVOH(x) below the above upper limit enhances adhesion with the inorganic vapor-deposited layer (I), which will be described later. Ethylene unit content refers to the amount of ethylene units (mol%) relative to the total structural units constituting the polymer (EVOH(x), etc.).

[0017] The lower limit of the degree of saponification of EVOH(x) is 80 mol%, preferably 85 mol%, more preferably 90 mol%, even more preferably 95 mol%, and even more preferably 97 mol%, 98 mol%, or 99 mol%. The degree of saponification of EVOH(x) etc. refers to the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH(x) etc. By having a degree of saponification of EVOH(x) above the lower limit, the gas barrier properties can be further enhanced. The upper limit of the degree of saponification of EVOH(x) may be 100 mol%, or it may be 99.9 mol%. The ethylene unit content and degree of saponification of EVOH(x) etc. are: １ It can be determined by H-NMR measurement.

[0018] EVOH(x) may have other structural units other than ethylene units, vinyl alcohol units and any remaining vinyl ester units, as long as they do not impair the effects of the present invention. Examples of monomers that give the above other structural units include α-olefins such as propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and its salts; unsaturated monomers having an acrylic acid ester group; methacrylic acid and its salts; unsaturated monomers having a methacrylic acid ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide, acrylamidopropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts (e.g., quaternary salts); methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidopropanesulfonic acid and its salts, methacrylamidopropyldimethylamine and its salts (e.g., quaternary salts); methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether Examples include vinyl ethers such as ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether, and 2,3-diacetoxy-1-vinyloxypropane; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; vinylidenes such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate, 2,3-diacetoxy-1-allyloxypropane, and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid, and their salts or esters; vinylsilane compounds such as vinyltrimethoxysilane; isopropenyl acetate, 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyronyloxy-2-methylenepropane.

[0019] EVOH(x) may or may not be post-modified by methods such as urethaneization, acetalization, cyanoethylation, or oxyalkyleneization.

[0020] When EVOH(x) has other structural units, it is preferable that EVOH(x) has a structural unit represented by the following formula (I).

[0021]

[0022] In formula (I), X represents a hydrogen atom, a methyl group or a group represented by R ２ -OH. R １ and R ２ each independently represent a single bond, an alkylene group having 1 to 9 carbon atoms or an alkyleneoxy group having 1 to 9 carbon atoms, and the alkylene group and the alkyleneoxy group may contain a hydroxy group, an alkoxy group or a halogen atom.

[0023] X is preferably a hydrogen atom or a group represented by R ２ -OH, and more preferably a group represented by R ２ -OH.

[0024] R １ or R ２ The alkylene group and the alkyleneoxy group used as may contain a hydroxy group, an alkoxy group or a halogen atom. R １ and R ２ are preferably an alkylene group or an alkyleneoxy group having 1 to 5 carbon atoms, and more preferably an alkylene group or an alkyleneoxy group having 1 to 3 carbon atoms.

[0025] Specific examples of the structural unit represented by formula (I) include, for example, structural units represented by the following formula (II), formula (III) and formula (IV), and among them, the structural unit represented by formula (II) is preferable.

[0026]

[0027] In formula (II), R ３ and R ４ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and the alkyl group may contain a hydroxy group, an alkoxy group or a halogen atom.

[0028]

[0029] In formula (III), R ５R is equivalent to X in equation (I). ６ This represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and the alkyl group may include a hydroxyl group, an alkoxy group, or a halogen atom.

[0030]

[0031] In formula (IV), R ７ and R ８ Each of these independently represents a hydrogen atom, a C1-C8 alkyl group, a C3-C8 cycloalkyl group, or a hydroxyl group. Furthermore, some or all of the hydrogen atoms in the alkyl and cycloalkyl groups may be substituted with hydroxyl groups, alkoxy groups, or halogen atoms.

[0032] R in equation (I) １ The bond is a single bond, and X is a hydroxymethyl group (R in formula (II)). ３ , R ４ Preferably, the structural unit is a hydrogen atom. Using EVOH(x) having this structural unit tends to improve secondary processing properties such as stretchability and thermoformability without significantly worsening gas barrier properties. When EVOH(x) contains the above structural unit, the lower limit of its content is preferably 0.1 mol%, more preferably 0.4 mol%, and even more preferably 1.0 mol%. On the other hand, the upper limit of the content of the above structural unit is preferably 20 mol%, more preferably 10 mol%, even more preferably 8 mol%, and particularly preferably 5 mol% from the viewpoint of good gas barrier properties.

[0033] R in equation (I) １ R is a hydroxymethylene group, and X is a hydrogen atom (R in formula (III)). ５ , R ６It is also preferable that the structural unit is a hydrogen atom. Using EVOH(x) having this structural unit tends to improve secondary processing properties such as stretchability and thermoformability without significantly worsening gas barrier properties. When EVOH(x) contains the above structural unit, the lower limit of its content is preferably 0.1 mol%, more preferably 0.4 mol%, and even more preferably 1.0 mol%. On the other hand, the upper limit of the content of the above structural unit is preferably 20 mol%, more preferably 10 mol%, even more preferably 8 mol%, and particularly preferably 5 mol% from the viewpoint of good gas barrier properties.

[0034] R in equation (I) １ It is also preferable that is a methylmethyleneoxy group and X is a hydrogen atom. By using EVOH(x) having this structural unit, secondary processing properties such as stretchability and thermoformability tend to be improved without significantly worsening gas barrier properties. Furthermore, in the above methylmethyleneoxy group, the oxygen atom is bonded to the carbon atom of the main chain. That is, in formula (IV), R ７ , R ８ Preferably, one of the structural units is a methyl group and the other is a hydrogen atom. When EVOH(x) contains the above structural unit, the lower limit of its content is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1.0 mol%, and particularly preferably 2.0 mol%. On the other hand, the upper limit of the content of the above structural unit is preferably 20 mol%, more preferably 15 mol%, and even more preferably 10 mol% from the viewpoint of good gas barrier properties.

[0035] The upper limit of the content of other structural units (structural units other than ethylene units, vinyl alcohol units, and optionally residual vinyl ester units) relative to the total structural units of EVOH(x) is preferably 5 mol%, more preferably 3 mol%, and even more preferably 1 mol%. In other words, the lower limit of the total content of ethylene units, vinyl alcohol units, and optionally residual vinyl ester units relative to the total structural units of EVOH is preferably 95 mol%, more preferably 97 mol%, and even more preferably 99 mol%. EVOH(x) may not have other structural units.

[0036] The lower limit of the MFR (190°C, 2.16 kg load) for EVOH(x) is preferably 0.5 g / 10 min, more preferably 1.0 g / 10 min, and even more preferably 1.5 g / 10 min. The upper limit of the MFR (190°C, 2.16 kg load) for EVOH(x) is preferably 5.0 g / 10 min, more preferably 3.0 g / 10 min, and even more preferably 2.0 g / 10 min. The lower limit of the MFR (210°C, 2.16 kg load) for EVOH(x) is preferably 1.0 g / 10 min, more preferably 2.0 g / 10 min, and even more preferably 3.0 g / 10 min. The upper limit of the MFR (Mold Free Filtration Rate) of EVOH(x) (210°C, 2.16 kg load) is preferably 10 g / 10 min, more preferably 7.0 g / 10 min, and even more preferably 5.0 g / 10 min. Having the MFR of EVOH(x) within this range allows for good melt moldability. The MFR of EVOH(x) and the like is measured in accordance with JIS K7210-1 (2014).

[0037] The lower limit of the melting point of EVOH(x) is preferably 120°C, more preferably 130°C, even more preferably 140°C, even more preferably 150°C, and particularly preferably 160°C. The upper limit of the melting point of EVOH(x) is preferably 230°C, more preferably 220°C, even more preferably 210°C, and even more preferably 200°C. Having the melting point of EVOH(x) within the above range allows for good melt moldability, etc.

[0038] EVOH(x) can be manufactured by conventionally known methods. Commercially available EVOH(x) may also be used.

[0039] The lower limit of the EVOH(x) content in layer (X) is preferably 70% by mass, more preferably 80% by mass, even more preferably 90% by mass, and may also be 95% by mass, 99% by mass, or 99.9% by mass. The upper limit of the EVOH(x) content in layer (X) may be 100% by mass, or may be 99.99% by mass, 99.9% by mass, or 99% by mass.

[0040] Layer (X) may contain components other than EVOH(x). Examples of other components include boron compounds, carboxylic acids, phosphorus compounds, metal ions, resins other than EVOH(x), antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, and heat stabilizers. Layer (X) may contain two or more of these optional components.

[0041] The average thickness of layer (X) is preferably 30 μm or less, and more preferably less than 20 μm. Having an average thickness of layer (X) below the above upper limit allows for thinner and lighter multilayer films, as well as improved recyclability and flexibility. The upper limit of the average thickness of layer (X) is more preferably 10 μm, even more preferably 7 μm, and may be 5 μm, 4 μm, or 3 μm. On the other hand, the lower limit of the average thickness of layer (X) is preferably 0.2 μm, more preferably 0.5 μm, even more preferably 1 μm, and may be 1.5 μm or 2 μm. Having an average thickness of layer (X) above the above lower limit allows for improved gas barrier properties. If layer (X) consists of multiple layers, the average thickness of layer (X) is the average thickness of the sum of the multiple layers (X).

[0042] The ratio of the average thickness of layer (X) to the average thickness of the multilayer film is preferably less than 25%. Having the ratio of the average thickness of layer (X) below the above upper limit enhances recyclability. The upper limit of the above average thickness ratio is more preferably 20%, and even more preferably 15%. The lower limit of the above average thickness ratio may be, for example, 1%, 3%, or 5%.

[0043] Layer (X) may consist of a single layer or multiple layers. In one embodiment, it is preferable that layer (X) is a single layer. Note that if multiple layers made of the same material composition are directly laminated, they are considered as a single layer. The same applies to other layers.

[0044] (Layer (Y)) Layer (Y) is a layer located between layer (X) and layer (Z). Layer (Y) mainly contains an ethylene-vinyl ester copolymer or its saponified product (y1) (polymer (y1)) having an ethylene unit content of 60 to 99 mol% and a degree of saponification of 0 to 99.9 mol%.

[0045] The copolymer (y1) may be an unsaponified copolymer of ethylene and a vinyl ester, or a saponified copolymer obtained by saponifying the copolymer of ethylene and a vinyl ester. Examples of vinyl esters include vinyl acetate, vinyl propionate, and vinyl pivalate, with vinyl acetate being preferred. When the vinyl ester is vinyl acetate, the copolymer (y1), i.e., the ethylene-vinyl acetate copolymer or its saponified form, is also called "EVA or partially saponified EVA". The copolymer (y1) is preferably EVA or partially saponified EVA.

[0046] The lower limit of the ethylene unit content of copolymer (y1) is 60 mol%, preferably 70 mol%, more preferably 80 mol%, and even more preferably 85 mol% or 90 mol%. Having an ethylene unit content of copolymer (y1) above the above lower limit enhances compatibility with polypropylene (z), etc., improving interlayer adhesion, recyclability, etc. The upper limit of the ethylene unit content of copolymer (y1) is 99 mol%, preferably 96 mol%, more preferably 94 mol%, and even more preferably 93 mol%.

[0047] Furthermore, by increasing the ethylene unit content of the copolymer (y1) to enhance its compatibility with polypropylene (z), the main component of layer (Z), and by relatively reducing the vinyl alcohol unit content (described later), the adhesion between layers (X) and (Y) tends to improve. The reason for this is not entirely clear, but it is thought that the compatibility of the resins between each layer is influenced by the lamination of highly compatible resins by co-extrusion. For example, it is speculated that the compatibility of the resins between layers (X) and (Y), and between layers (Y) and (Z), causes the non-polar portion of the copolymer (y1) in the relatively thin layer (Y) to be biased towards layer (Z) and the polar portion to be biased towards layer (X), thereby strengthening the hydrogen bonds between layers (X) and (Y).

[0048] The lower limit of the degree of saponification of copolymer (y1) is 0 mol%, preferably 1 mol%, more preferably 2 mol%, even more preferably 3 mol%, and even more preferably 6 mol%. When the degree of saponification of copolymer (y1) is above the above lower limit, interlayer adhesion, gas barrier properties, recyclability, etc. tend to be improved. The lower limit of the degree of saponification of copolymer (y1) may be 8 mol%, 10 mol%, 30 mol%, 50 mol%, 70 mol%, or 90 mol%. The upper limit of the degree of saponification of copolymer (y1) is 99.9 mol%, preferably 99 mol%, more preferably 98 mol%, even more preferably 90 mol%, and even more preferably 80 mol%, 70 mol%, 60 mol%, 50 mol%, 40 mol%, 30 mol%, 20 mol%, or 12 mol%. By keeping the degree of saponification of the copolymer (y1) below the above upper limit, interlayer adhesion, recyclability, etc., can be improved. The range of the degree of saponification of the copolymer (y1) may be, for example, 3 to 99.9 mol%, or 6 to 20 mol%. The degree of saponification of the copolymer (y1) may also be less than 10 mol%, less than 5 mol%, less than 1 mol%, or less than 0.3 mol%.

[0049] The lower limit of the content of vinyl ester units relative to the total structural units of copolymer (y1) is preferably 0.1 mol%, more preferably 0.5 mol%, even more preferably 1 mol%, and even more preferably 2 mol%, 3 mol%, 4 mol%, 5 mol%, or 6 mol%. The upper limit of the content of vinyl ester units relative to the total structural units of copolymer (y1) is preferably 20 mol%, more preferably 15 mol%, even more preferably 10 mol%, and even more preferably 8 mol%. By having the content of vinyl ester units relative to the total structural units of copolymer (y1) within the above range, it is possible to further improve adhesion to layer (X), etc.

[0050] The lower limit of the vinyl alcohol unit content relative to the total structural units of copolymer (y1) is preferably 0.1 mol%, more preferably 0.3 mol%, and even more preferably 0.5 mol%. The upper limit of the vinyl alcohol unit content relative to the total structural units of copolymer (y1) is preferably 20 mol%, more preferably 15 mol%, even more preferably 10 mol%, and even more preferably 8 mol%, 6 mol%, 4 mol%, 3 mol%, 2 mol%, or 1 mol%. By having a vinyl alcohol unit content relative to the total structural units of copolymer (y1) that is above the above lower limit, interlayer adhesion and recyclability can be further improved. The range of vinyl alcohol unit content relative to the total structural units of copolymer (y1) may be, for example, 0.3 to 15 mol%, or 0.4 to 3 mol%.

[0051] The copolymer (y1) may have structural units other than ethylene units, vinyl ester units, and vinyl alcohol units, as long as they do not impair the effects of the present invention. The monomers that provide the above-mentioned other structural units are the same as those exemplified as monomers that provide the other structural units in EVOH(x).

[0052] The upper limit of the content of other structural units (structural units other than ethylene units, vinyl ester units, and vinyl alcohol units) relative to the total structural units of copolymer (y1) is preferably 5 mol%, more preferably 3 mol%, and still more preferably 1 mol%. In other words, the lower limit of the total content of ethylene units, vinyl ester units, and vinyl alcohol units relative to the total structural units of copolymer (y1) is preferably 95 mol%, more preferably 97 mol%, and still more preferably 99 mol%. In particular, from the viewpoint of suppressing deterioration of appearance due to excessive crosslinking reaction with EVOH(x), the upper limit of the content of structural units having acidic groups (carboxyl groups, sulfo groups, etc.) relative to the total structural units of copolymer (y1) is preferably 5 mol%, more preferably 3 mol%, still more preferably 1 mol%, and still more preferably 0.5 mol%. Copolymer (y1) does not have to have other structural units.

[0053] The lower limit of the MFR (190°C, 2.16 kg load) of copolymer (y1) is preferably 0.5 g / 10 min, more preferably 1.0 g / 10 min, and even more preferably 2.0 g / 10 min. The upper limit of the MFR (190°C, 2.16 kg load) of copolymer (y1) is preferably 15 g / 10 min, more preferably 10 g / 10 min, and even more preferably 8.0 g / 10 min. When the MFR of copolymer (y1) is within the above range, it is possible to exhibit good melt moldability and further improve interlayer adhesion.

[0054] The lower limit of the melting point of copolymer (y1) is preferably 50°C, more preferably 60°C, and even more preferably 70°C. The upper limit of the melting point of copolymer (y1) is preferably 150°C, more preferably 120°C, and even more preferably 100°C. Having the melting point of copolymer (y1) within the above range enhances adhesion to layer (X) and exhibits good melt moldability.

[0055] The copolymer (y1) can be produced by conventionally known methods. These copolymers (y1) may be commercially available.

[0056] The lower limit of the copolymer (y1) content in layer (Y) is preferably 60% by mass, more preferably 70% by mass, even more preferably 75% by mass, and even more preferably 80% by mass. If the degree of saponification of copolymer (y1) is less than 1 mol%, the upper limit of the copolymer (y1) content in layer (Y) may be 100% by mass. The upper limit of the copolymer (y1) content in layer (Y) may also be 99% by mass, 95% by mass, 90% by mass, or 86% by mass.

[0057] When the degree of saponification of the copolymer (y1) is 1 to 99.9 mol%, it is preferable that the layer (Y) further contains a tackifier (y2). When the degree of saponification of the copolymer (y1) is 1 to 99.9 mol%, the layer (Y) does not need to contain a tackifier (y2). When the degree of saponification of the copolymer (y1) is less than 1 mol%, the layer (Y) further contains a tackifier (y2). By including a tackifier (y2) in the layer (Y), interlayer adhesion can be improved, and recyclability also tends to improve.

[0058] Examples of tackifiers (y2) include: coumarone resins such as coumarone-indene resin; phenolic resins such as p-t-butylphenol-acetylene resin, phenol-formaldehyde resin, and xylene-formaldehyde resin; terpene resins such as terpene resins such as tackifier, terpene-phenol resin, and aromatic terpene resin; petroleum resins such as aromatic petroleum resins, aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, and modified alicyclic petroleum resins; rosin resins such as rosin esters represented by pentaerythritol ester of rosin and glycerol ester of rosin, hydrogenated rosin, methyl ester of hydrogenated rosin, pentaerythritol ester of polymerized rosin, hydrogenated rosin ester, high melting point ester resins, polymerized rosin, cured rosin, and special rosin esters; and others. These may be used individually or in combination of two or more.

[0059] The tackifier (y2) is preferably at least one selected from the group consisting of petroleum resins, terpene resins, and rosin resins, more preferably petroleum resins, and even more preferably hydrogenated petroleum resins. The tackifier (y2) is also preferably a hydrocarbon resin, in which case it is more preferably a saturated hydrocarbon resin, and even more preferably an alicyclic saturated hydrocarbon resin. Examples of tackifiers that are both hydrogenated petroleum resins and alicyclic saturated hydrocarbon resins include "Alcon P-100" and "Alcon P-125" manufactured by Arakawa Chemical Industries, Ltd. Since such tackifiers (y2) can function as good compatibilizers, they can further improve interlayer adhesion and recyclability.

[0060] The lower limit of the softening point (ring-sphere method) of the tackifier (y2) is preferably 80°C, more preferably 90°C, even more preferably 100°C, and even more preferably 110°C. The upper limit of the softening point (ring-sphere method) is preferably 160°C, more preferably 150°C, even more preferably 140°C, and even more preferably 130°C. Having the softening point of the tackifier (y2) within the above range allows for particularly good compatibility, which in turn enhances interlayer adhesion and recyclability.

[0061] When the degree of saponification of copolymer (y1) is 1 to 99.9 mol%, the lower limit of the content of tackifier (y2) per 100 parts by mass of copolymer (y1) in layer (Y) is preferably 1 part by mass, more preferably 5 parts by mass, even more preferably 10 parts by mass, and even more preferably 15 parts by mass. A content of tackifier (y2) above the above lower limit can further improve interlayer adhesion, recyclability, etc. When the degree of saponification of copolymer (y1) is 1 to 99.9 mol%, the upper limit of the content of tackifier (y2) per 100 parts by mass of copolymer (y1) in layer (Y) is 30 parts by mass, preferably 27 parts by mass, and more preferably 24 parts by mass. A content of tackifier (y2) below the above upper limit can improve gas barrier properties, etc.

[0062] When the degree of saponification of copolymer (y1) is less than 1 mol%, the lower limit of the content of tackifier (y2) per 100 parts by mass of copolymer (y1) in layer (Y) is 1 part by mass, preferably 5 parts by mass, more preferably 10 parts by mass, and even more preferably 15 parts by mass. A content of tackifier (y2) above the above lower limit can improve interlayer adhesion, recyclability, etc. When the degree of saponification of copolymer (y1) is less than 1 mol%, the upper limit of the content of tackifier (y2) per 100 parts by mass of copolymer (y1) in layer (Y) is 30 parts by mass, preferably 27 parts by mass, and more preferably 24 parts by mass. A content of tackifier (y2) below the above upper limit can improve gas barrier properties, etc.

[0063] The lower limit of the total content of copolymer (y1) and tackifier (y2) in layer (Y) is preferably 80% by mass, more preferably 90% by mass, and may be 95% by mass, 99% by mass, or 99.9% by mass. The upper limit of the total content of copolymer (y1) and tackifier (y2) in layer (Y) may be 100% by mass, or may be 99.99% by mass, 99.9% by mass, or 99% by mass.

[0064] Layer (Y) may contain components other than the copolymer (y1) and the tackifier (y2). Examples of other components include boron compounds, carboxylic acids, phosphorus compounds, metal ions, resins other than the copolymer (y1) and the tackifier (y2), antioxidants, UV absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, and heat stabilizers. Layer (Y) may contain two or more of these optional components.

[0065] The average thickness of layer (Y) is preferably less than 20 μm. Having an average thickness of layer (Y) below the above upper limit allows for thinner and lighter multilayer films, improved recyclability, etc. The upper limit of the average thickness of layer (Y) is more preferably 10 μm, even more preferably 7 μm, and may be 5 μm, 4 μm, or 3 μm. On the other hand, the lower limit of the average thickness of layer (Y) is preferably 0.2 μm, more preferably 0.5 μm, even more preferably 1 μm, and may be 1.5 μm or 2 μm. Having an average thickness of layer (Y) above the above lower limit allows for improved interlayer adhesion, etc. If layer (Y) consists of multiple layers, the average thickness of layer (Y) is the average thickness of the sum of the multiple layers (Y).

[0066] The ratio of the average thickness of layer (Y) to the average thickness of the multilayer film is preferably less than 25%. Having the ratio of the average thickness of layer (Y) below the above upper limit enhances recyclability. The upper limit of the above average thickness ratio is more preferably 20%, and even more preferably 15%. The lower limit of the above average thickness ratio may be, for example, 1%, 3%, or 5%.

[0067] The layer (Y) may consist of a single layer or multiple layers. In one embodiment, it is preferable that the layer (Y) is a single layer.

[0068] (Layer (Z)) Layer (Z) is a layer laminated on the opposite side of layer (Y) from layer (X). Layer (Z) may be the outermost layer on the opposite side of layer (X) in a multilayer film. When layer (Z) is the outermost layer, layer (Z) may also function as a sealant layer (heat seal layer). Layer (Z) mainly contains polypropylene (z).

[0069] Polypropylene (z) can be homopolymer (homopolypropylene; h-PP), random copolymer (random polypropylene; r-PP), block polymer (block polypropylene; b-PP), etc. An example of a random copolymer is polypropylene obtained by random copolymerization of ethylene. An example of a block copolymer is a copolymer having ethylene blocks and propylene blocks.

[0070] Random copolymers are preferred as polypropylene (z). Among polypropylenes, random copolymers have relatively high compatibility with copolymer (y1). Therefore, by using random copolymers as polypropylene (z), interlayer adhesion, recyclability, etc., can be further improved. Although the reason is not clear, by using a random copolymer, which has relatively high compatibility with copolymer (y1), the main component of layer (Y), as the polypropylene (z) of layer (Z), the adhesion between layer (X) and layer (Y) tends to improve. The reason for this is not clear, but it is thought that the compatibility of each resin between layers is influenced by the lamination of each highly compatible resin by co-extrusion. For example, it is speculated that the compatibility of each resin between layer (X) and layer (Y), and between layer (Y) and layer (Z), causes the non-polar portion of copolymer (y1) in the relatively thin layer (Y) to be biased towards layer (Z) and the polar portion to be biased towards layer (X), thereby strengthening the hydrogen bonds between layer (X) and layer (Y).

[0071] The lower limit of the MFR (Mold Free Load) of polypropylene (z) (190°C, 2.16 kg load) is preferably 1.0 g / 10 min, more preferably 2.0 g / 10 min, even more preferably 3.0 g / 10 min, and even more preferably 4.0 g / 10 min, 4.5 g / 10 min, or 5.0 g / 10 min. The upper limit of the MFR (Mold Free Load) of polypropylene (z) (190°C, 2.16 kg load) is preferably 15 g / 10 min, more preferably 10.0 g / 10 min, and even more preferably 7.0 g / 10 min. When the MFR of polypropylene (z) is within the above range, it is possible to exhibit good melt moldability, further improve interlayer adhesion, recyclability, etc.

[0072] The lower limit of the melting point of polypropylene (z) is preferably 90°C, more preferably 100°C, and even more preferably 110°C. The upper limit of the melting point of the thermoplastic resin (z) is preferably 180°C, more preferably 160°C, even more preferably 150°C, and even more preferably 140°C. Having the melting point of polypropylene (z) within the above range allows for good melt moldability, improved interlayer adhesion, recyclability, heat sealability, etc. In particular, when layer (Z) is located on the outermost surface and consists of multiple layers, it is preferable that the melting point of the main component polypropylene (z) of the outermost layer (the layer furthest from layer (Y)) among the multiple layers (Z) be within the above range. In such a case, there is an advantage that the outermost layer within layer (Z) can function suitably as a sealant layer.

[0073] Polypropylene (z) can be manufactured by conventionally known methods. Commercially available polypropylene may also be used.

[0074] The lower limit of the polypropylene (z) content in layer (Z) is preferably 70% by mass, more preferably 80% by mass, even more preferably 90% by mass, and may also be 95% by mass, 99% by mass, or 99.9% by mass. The upper limit of the polypropylene (z) content in layer (Z) may be 100% by mass, or may be 99.99% by mass, 99.9% by mass, or 99% by mass.

[0075] Layer (Z) may contain components other than polypropylene (z). Examples of other components include antioxidants, UV absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, heat stabilizers, and resins other than polypropylene (z). Layer (Z) may contain two or more of these optional components.

[0076] The upper limit of the average thickness of layer (Z) is preferably 200 μm, more preferably 100 μm, even more preferably 50 μm, and even more preferably 30 μm. By keeping the average thickness of layer (Z) below the above upper limit, it is possible to make the multilayer film thinner. The lower limit of the average thickness of layer (Z) is preferably 1 μm, more preferably 5 μm, even more preferably 10 μm, even more preferably 15 μm, and particularly preferably 20 μm. By keeping the average thickness of layer (Z) above the above lower limit, it is possible to further improve melt moldability, barrier properties, etc. If layer (Z) consists of multiple layers, the average thickness of layer (Z) is the average thickness of the sum of the multiple layers (Z).

[0077] The lower limit of the ratio of the average thickness of layer (Z) to the average thickness of the multilayer film is preferably 50%, more preferably 60%, and even more preferably 70% or 80%. A ratio of the average thickness of layer (Z) above the above lower limit enhances recyclability. The upper limit of the above average thickness ratio is preferably 95%, more preferably 90%.

[0078] The layer (Z) may consist of a single layer or multiple layers. In one embodiment, it is preferable that the layer (Z) is a single layer.

[0079] A layer (Z) consisting of multiple layers may consist of multiple layers mainly composed of polypropylene (z), where the type of polypropylene (z) differs between adjacent layers. When layer (Z) is located at the outermost layer and consists of multiple layers, it is preferable that the polypropylene (z) that is the main component of the outermost layer of the multiple layers (Z) has a lower melting point than the polypropylene (z) that is the main component of the other layers. When layer (Z) has such a layered structure, it has advantages such as the outermost layer of layer (Z) being able to function suitably as a sealant layer.

[0080] (Layer structure of multilayer film, etc.) The multilayer film of the present invention usually consists only of layer (X), layer (Y), and layer (Z). The multilayer film may further have other layers besides layer (X), layer (Y), and layer (Z). Examples of the layer structure of the multilayer film include X / Y / Z, X / Y / Z / Y / X, etc., where X / Y / Z is represented by X, layer (Y) by Y, and layer (Z) by Z, and X / Y / Z is preferred.

[0081] The upper limit of the average thickness of the multilayer film is preferably 300 μm, more preferably 200 μm, even more preferably 100 μm, and in some cases 70 μm, 60 μm, 50 μm, or 40 μm are even more preferred. By keeping the average thickness of the multilayer film below the above upper limit, it is possible to achieve thinner films and cost reductions. Furthermore, the multilayer film of the present invention, and vapor-deposited multilayer films using this multilayer film, can exhibit excellent barrier properties despite the thinness of the multilayer film. The lower limit of the average thickness of the multilayer film is preferably 5 μm, more preferably 10 μm, even more preferably 15 μm, and in some cases 20 μm or 25 μm are even more preferred. By keeping the average thickness of the multilayer film above the above lower limit, it is possible to enhance the barrier properties.

[0082] The multilayer film of the present invention may be an unstretched film or a stretched film that is stretched at least in one axial direction. An unstretched film means a film that has not been stretched, but some orientation during film formation (for example, orientation as if stretched 1.01 times) is considered as being unstretched. When it is an unstretched film, it has advantages such as excellent impact resistance, and, for example, when layer (Z) is located on the outermost layer, layer (Z) functions particularly effectively as a sealant layer.

[0083] When the multilayer film of the present invention is a stretched film, it is preferable that it is stretched by at least 3 times or more but less than 12 times in at least one axis direction, and more preferably by at least 4 times or more but less than 8 times in at least one axis direction. When the multilayer film is a stretched film, it may be a uniaxially oriented film or a biaxially oriented film. A uniaxially oriented film stretched only in one axis direction is considered to be uniaxially stretched, ignoring any slight orientation in the other axis direction during film formation (for example, orientation as if stretched by 1.01 times). When the multilayer film is a stretched film, it is possible to further enhance barrier properties, improve mechanical properties, etc.

[0084] The multilayer film of the present invention is a co-extruded multilayer film. That is, the multilayer film is a film manufactured by a co-extrusion method. By employing the co-extrusion method, a multilayer film with good film properties such as barrier properties and flexibility can be manufactured with high productivity. Examples of co-extrusion methods include co-extrusion casting, co-extrusion inflation molding, and co-extrusion coating. The method of stretching in the uniaxial or biaxial direction is not particularly limited, and the film can be manufactured by stretching the film in the direction of flow and / or in the direction perpendicular to the flow direction, i.e., in the width direction, using conventionally known stretching methods such as roll-type uniaxial stretching, tenter-type uniaxial stretching, tubular-type simultaneous biaxial stretching, tenter-type sequential biaxial stretching, and tenter-type simultaneous biaxial stretching. Furthermore, in tenter-type sequential biaxial stretching, tenter-type stretching may be used for both axes, or a combination of roll-type stretching and tenter-type stretching may be used. The temperature during stretching is usually 40 to 170°C, and preferably 50 to 160°C, from the viewpoint of processability. If necessary, it is preferable to perform a so-called thermal fixation operation after the stretching process at a temperature above the glass transition point but below the melting point to increase the degree of crystallinity and fix the orientation of the molecular chains.

[0085] <Vaporized Multilayer Film> The vapor-deposited multilayer film of the present invention comprises the multilayer film of the present invention described above and an inorganic vapor-deposited layer (I). The inorganic vapor-deposited layer (I) is a metal vapor-deposited layer mainly composed of aluminum or an inorganic oxide vapor-deposited layer mainly composed of alumina or silica, laminated on the exposed surface side of layer (X) in the multilayer film. The vapor-deposited multilayer film uses a multilayer film that achieves both appearance characteristics and interlayer adhesion, and also has excellent gas barrier properties.

[0086] (Inorganic vapor-deposited layer (I)) In the vapor-deposited multilayer film, the inorganic vapor-deposited layer (I) is usually laminated directly onto the surface of layer (X). The inorganic vapor-deposited layer (I) is a layer that has excellent barrier properties against oxygen, water vapor, etc. Layer (X) has a higher affinity for metals and inorganic oxides compared to ordinary thermoplastic resins, and can form a dense and defect-free inorganic vapor-deposited layer (I), resulting in good interlayer adhesion between layer (X) and the inorganic vapor-deposited layer (I) in the resulting vapor-deposited multilayer film. Furthermore, because layer (X), etc., has barrier properties, even if defects occur in the inorganic vapor-deposited layer (I) due to bending, etc., the decrease in barrier properties can be suppressed.

[0087] The inorganic vapor-deposited layer (I) is either a metal vapor-deposited layer containing aluminum as the main component or an inorganic oxide vapor-deposited layer containing alumina or silica as the main component. A metal vapor-deposited layer is preferred when light shielding is required, while an inorganic oxide vapor-deposited layer is preferred from the viewpoint of visibility of the contents as a packaging material, suitability for the range, and suppression of discoloration when melting and molding the crushed material.

[0088] The lower limit of the aluminum atom content in the metal vapor deposition layer is preferably 70% by mass, more preferably 90% by mass, and even more preferably 95% by mass. The upper limit of the aluminum atom content in the metal vapor deposition layer may be 100% by mass.

[0089] In metal vapor deposition layers mainly composed of aluminum, irreversible oxidation occurs, and some aluminum oxide may be present. In metal vapor deposition layers mainly composed of aluminum (inorganic vapor deposition layer (I)), the molar ratio of oxygen atoms to aluminum atoms (Omol / Almol) is preferably 0.5 or less, more preferably 0.3 or less, and even more preferably 0.1 or less.

[0090] The lower limit of the alumina or silica content in the inorganic oxide vapor deposition layer is preferably 70% by mass, more preferably 90% by mass, and even more preferably 95% by mass. The upper limit of the alumina or silica content in the inorganic oxide vapor deposition layer may be 100% by mass.

[0091] The upper limit of the average thickness of the inorganic vapor-deposited layer (I) is preferably 200 nm, more preferably 120 nm, even more preferably 100 nm, even more preferably 80 nm, and particularly preferably 60 nm. By setting the average thickness of the inorganic vapor-deposited layer (I) to be below the above upper limit, productivity can be increased, and in particular, if the inorganic vapor-deposited layer (I) is an inorganic oxide vapor-deposited layer, visibility, light transmission, etc. can be improved. The lower limit of the average thickness of the inorganic vapor-deposited layer (I) is preferably 10 nm, more preferably 20 nm, even more preferably 30 nm, and even more preferably 40 nm. By setting the average thickness of the inorganic vapor-deposited layer (I) to be above the above lower limit, barrier properties can be further improved, and in particular, if the inorganic vapor-deposited layer (I) is a metal vapor-deposited layer, light shielding properties can be improved. If the inorganic vapor-deposited layer (I) consists of multiple layers, the average thickness of the inorganic vapor-deposited layer (I) may be the average thickness of the sum of the multiple inorganic vapor-deposited layers (I), or it may be the average thickness of a single inorganic vapor-deposited layer (I).

[0092] The inorganic vapor-deposited layer (I) may consist of a single layer or multiple layers. In one embodiment, the inorganic vapor-deposited layer (I) is preferably a single layer.

[0093] The inorganic vapor-deposited layer (I) can be formed by known physical vapor deposition methods or chemical vapor deposition methods. Specifically, examples include vacuum vapor deposition, sputtering, ion plating, ion beam mixing, plasma CVD, laser CVD, MO-CVD, and thermal CVD, but it is preferable to use a physical vapor deposition method, and among these, it is particularly preferable to use a vacuum vapor deposition method. The upper limit of the surface temperature of layer (X) during the formation of the inorganic vapor-deposited layer (I) is preferably 60°C, more preferably 55°C, and even more preferably 50°C. The lower limit of the surface temperature of layer (X) during the formation of the inorganic vapor-deposited layer (I) is not particularly limited, but it is preferably 0°C, more preferably 10°C, and even more preferably 20°C. Before forming the film, the exposed surface of layer (X) may be plasma-treated. Known methods can be used for plasma treatment, and atmospheric pressure plasma treatment is preferred. In atmospheric pressure plasma treatment, nitrogen, helium, neon, argon, krypton, xenon, radon, etc., can be used as the discharge gas. Among these, nitrogen, helium, and argon are preferably used, and nitrogen is particularly preferred because it can reduce costs. The flexibility may be improved by providing a known protective layer or the like on the inorganic vapor deposition layer (I).

[0094] (Layer structure of vapor-deposited multilayer film) The vapor-deposited multilayer film of the present invention may further have other layers besides layer (X), layer (Y), layer (Z), and inorganic vapor-deposited layer (I). Other layers include other resin layers, etc. It is also preferable that the vapor-deposited multilayer film does not have any other layers besides layer (X), layer (Y), layer (Z), and inorganic vapor-deposited layer (I). As for the layer structure of the vapor-deposited multilayer film, when layer (X) is represented by X, layer (Y) by Y, layer (Z) by Z, and inorganic vapor-deposited layer (I) by I, examples include I / X / Y / Z, I / X / Y / Z / Y / X / I, etc., with I / X / Y / Z being preferred.

[0095] The upper limit of the average thickness of the vapor-deposited multilayer film is preferably 300 μm, more preferably 200 μm, even more preferably 100 μm, and in some cases 70 μm, 60 μm, 50 μm, or 40 μm are even more preferred. By keeping the average thickness of the vapor-deposited multilayer film below the above upper limit, it is possible to make the film thinner. Furthermore, despite being such a thin vapor-deposited multilayer film, the vapor-deposited multilayer film of the present invention can exhibit excellent barrier properties. The lower limit of the average thickness of the vapor-deposited multilayer film is preferably 5 μm, more preferably 10 μm, even more preferably 15 μm, and in some cases 20 μm or 25 μm are even more preferred. By keeping the average thickness of the vapor-deposited multilayer film above the above lower limit, it is possible to further enhance the barrier properties.

[0096] <Multilayer Structure> The multilayer structure of the present invention comprises the multilayer film or vapor-deposited multilayer film of the present invention described above and a layer (R).

[0097] (Layer (R)) Layer (R) may be laminated directly or via another layer on the exposed surface side of layer (X) in a multilayer film, for example, or on the exposed surface side of layer (Z) in a multilayer film, for example. Layer (R) may be laminated directly or via another layer on the exposed surface side of inorganic vapor-deposited layer (I) in a vapor-deposited multilayer film, or on the exposed surface side of layer (Z) in a vapor-deposited multilayer film, for example. By providing layer (R), various functions such as aesthetic appeal, durability (mechanical strength), and protection of the inorganic vapor-deposited layer (I) can be provided. In addition, layer (R) may be a layer that functions as a sealant layer. Layer (R) may be the outermost layer in a multilayer structure.

[0098] The layer (R) mainly contains a thermoplastic resin (r). Examples of thermoplastic resins (r) include polyolefins, polyesters (polyethylene terephthalate, etc.), polyamides (nylon-6, nylon-66, etc.), polystyrene, polyvinyl chloride, polyvinylidene chloride, acrylic resins, vinyl ester resins, polyurethane, and polycarbonate.

[0099] Polyolefin is preferred as the thermoplastic resin (r). Examples of polyolefins include polyethylene, polypropylene, polybutene, and polypentene, with polypropylene being preferred. In the multilayer structure comprising a layer (Z) mainly composed of polypropylene (z), if the thermoplastic resin (r) that is the main component of layer (R) is also polypropylene, recyclability can be improved.

[0100] The lower limit of the thermoplastic resin (r) content in layer (R) is preferably 70% by mass, more preferably 80% by mass, even more preferably 90% by mass, and may also be 95% by mass, 99% by mass, or 99.9% by mass. The upper limit of the thermoplastic resin (r) content in layer (R) may be 100% by mass, or may be 99.99% by mass, 99.9% by mass, or 99% by mass. Layer (R) may contain one or more optional components similar to those exemplified in layer (Z), for example.

[0101] The layer (R) may or may not be stretched. That is, for example, the layer (R) may be an unstretched film or a stretched film that is stretched at least in one axis direction. From the viewpoint of improving mechanical strength, it is preferable that it is stretched, and from the viewpoint of improving heat sealability, it is preferable that it is not stretched. If the layer (R) is stretched, for example, it is preferable that it is stretched at least twice or less than twelve times in one axis direction. The layer (R) may be stretched only in one axis direction or it may be stretched in two axes.

[0102] The lower limit of the average thickness of layer (R) is preferably 5 μm, more preferably 10 μm, and even more preferably 20 μm. Having an average thickness of layer (R) above the above lower limit can increase the mechanical strength of the multilayer structure. The upper limit of the average thickness of layer (R) is preferably 200 μm, more preferably 100 μm, even more preferably 50 μm, and even more preferably 30 μm. Having an average thickness of layer (R) below the above upper limit can reduce the thickness of the multilayer structure. If layer (R) consists of multiple layers, the average thickness of layer (R) may be the sum of the average thicknesses of the multiple layers (R), or it may be the average thickness of a single layer (R).

[0103] The layer (R) may consist of a single layer or multiple layers. In one embodiment, it is preferable that the layer (R) is a single layer.

[0104] The method for laminating a layer (R) onto a multilayer film or a vapor-deposited multilayer film is not particularly limited and can be carried out by known methods such as dry lamination or extrusion lamination. As the adhesive used for dry lamination, a two-component reaction type polyurethane adhesive that mixes and reacts a polyisocyanate component and a polyol component is preferred. To further enhance the barrier properties of the multilayer structure, it is also preferable to use a barrier adhesive such as "PASLIM" manufactured by DIC Corporation. It is also preferable to coat the surface of an inorganic vapor-deposited layer (I) or the like with a topcoat agent (for example, "MFB1002" manufactured by Michaelman, or "Takelac™ WPB-341" manufactured by Mitsui Chemicals, Inc.) before laminating the film as layer (R).

[0105] An adhesive layer may be formed between the multilayer film or vapor-deposited multilayer film and layer (R). The average thickness of the adhesive layer is preferably 0.5 to 5 μm, and more preferably 1 to 3 μm.

[0106] (Layer structure of the multilayer structure, etc.) The multilayer structure of the present invention may further comprise other layers as long as they do not impede the effects of the present invention. Examples of other layers include metal foil layers, other resin layers, etc. However, it is preferable that the multilayer structure of the present invention does not have any layers other than the layers, layer (R), and adhesive layer that constitute the multilayer film or vapor-deposited multilayer film.

[0107] Examples of the layer structure of the multilayer structure of the present invention include, when layer (X) is represented by X, layer (Y) by Y, layer (Z) by Z, inorganic vapor deposition layer (I) by I, and layer (R) by R, R / / X / Y / Z, X / Y / Z / / R, R / / X / Y / Z / / R, R / / I / X / Y / Z, R / / I / X / Y / Z / / R, R / / X / Y / Z / Y / X / / R, R / / I / X / Y / Z / Y / X / I / / R, etc.

[0108] The upper limit of the average thickness of the multilayer structure of the present invention is preferably 300 μm, more preferably 200 μm, and even more preferably 100 μm. Because the average thickness is below the above upper limit, the multilayer structure of the present invention is lightweight and flexible, and is therefore preferably used for flexible packaging applications. In addition, the amount of resin used in the multilayer structure is small, which reduces the environmental impact. The lower limit of the average thickness of the multilayer structure of the present invention is preferably 10 μm, and may be 20 μm, 30 μm, 40 μm, or 50 μm.

[0109] In the multilayer structure of the present invention, a high polypropylene content (content ratio) is preferable from the viewpoint of recyclability. The polyethylene content in the multilayer structure is preferably 80% by mass or more, and more preferably 85% by mass or more. Furthermore, the ratio of the total average thickness of the polypropylene-based layer to the average thickness of the multilayer structure is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and even more preferably 85% or more.

[0110] <Applications of Multilayer Films, Vapor-Deposited Multilayer Films, and Multilayer Structures> The multilayer films, vapor-deposited multilayer films, and multilayer structures of the present invention can be suitably used as packaging materials. These multilayer films, vapor-deposited multilayer films, and multilayer structures may also be used for applications other than packaging materials. Furthermore, since the multilayer films, vapor-deposited multilayer films, and multilayer structures of the present invention have high gas barrier properties and can be highly recyclable, they can be suitably used as materials for various types of packaging, such as food packaging, pharmaceutical packaging, industrial chemical packaging, and pesticide packaging. In particular, packaging materials comprising the multilayer films, vapor-deposited multilayer films, and multilayer structures of the present invention can be suitably used as packaging materials with excellent recyclability.

[0111] In the multilayer film, vapor-deposited multilayer film, and multilayer structure of the present invention, with the side of the multilayer film where layer (Z) is provided as the oxygen supply side, the oxygen permeation rate measured using nitrogen gas containing 2 volume% hydrogen gas as the carrier gas, under the conditions of temperature 20°C, humidity 65% ​​RH on the oxygen supply side, humidity 65% ​​RH on the carrier gas side, oxygen pressure 1 atm, and carrier gas pressure 1 atm, in accordance with the method described in JIS K7126-2 (isobaric method; 2006), is 0.5 cc / (m³). ２ Preferably, it should be less than or equal to 0.2 cc / (m³) days atm. ２ It is more preferable that the concentration is less than or equal to 0.1 cc / (m³). ２ It is even more preferable that it be less than or equal to (day ATM).

[0112] The multilayer film, vapor-deposited multilayer film, and multilayer structure of the present invention preferably do not have layers containing a resin with a melting point of 200°C or higher as the main component, and metal layers with an average thickness of 1 μm or more. In other words, it is preferable that layers (X), (Y), (Z), and (R) do not contain a resin with a melting point of 200°C or higher as the main component. By not having layers containing a resin with a melting point of 200°C or higher as the main component, and metal layers with an average thickness of 1 μm or more, it is possible to suppress uneven mixing with other components when melt-molding pulverized materials such as multilayer films. Here, a metal layer refers to a layer made of metal, such as aluminum foil, that has continuous and discontinuous surfaces.

[0113] <Packaging Material> The packaging material of the present invention comprises a multilayer film, a vapor-deposited multilayer film, or a multilayer structure of the present invention. The packaging material may consist of a multilayer film, a vapor-deposited multilayer film, or a multilayer structure of the present invention. The packaging material is used for packaging purposes and its shape is not limited. The packaging material may be in the form of a sheet, or it may be molded into a predetermined shape such as a bag or a tube. From the viewpoint of heat sealability, it is preferable that layer (Z) or layer (R) is located on the outermost surface, and it is more preferable that an unstretched layer (Z) or unstretched layer (R) is located on the outermost surface.

[0114] The packaging material of the present invention is used for packaging, for example, food, beverages, pharmaceuticals, industrial chemicals, pesticides, medical equipment, machine parts, clothing, etc. In particular, the packaging material is preferably used in applications where barrier properties against water vapor and oxygen are required, and in applications where the inside of the packaging material is replaced with various functional gases.

[0115] <Recovered Composition, Recycling Method> It is preferable to reuse recovered materials (scrap) obtained by recovering edges and defective products generated during the manufacture of the multilayer film, vapor-deposited multilayer film, or multilayer structure of the present invention. In other words, a recovered composition containing recovered materials of the multilayer film, vapor-deposited multilayer film, or multilayer structure of the present invention is also a preferred embodiment of the present invention.

[0116] Furthermore, the recycling method of the present invention comprises the steps of obtaining crushed material by crushing the multilayer film, vapor-deposited multilayer film, or multilayer structure of the present invention, and melt-molding a composition containing the crushed material.

[0117] Regarding the recycling method of the present invention, first, the recovered multilayer film, vapor-deposited multilayer film, or multilayer structure (recovered multilayer film, vapor-deposited multilayer film, or multilayer structure) is crushed. The recovered composition is obtained by adding other components as necessary to the crushed material. The other components to be added to the crushed material are preferably polyolefins, and more preferably polypropylene. The recovered composition may be in a crushed state or in a molten state.

[0118] The recovered composition (a composition containing recovered multilayer film, vapor-deposited multilayer film, or crushed multilayer structure) may be directly melt-molded and used in the manufacture of molded articles. Alternatively, the recovered composition (a composition containing recovered multilayer film, vapor-deposited multilayer film, or crushed multilayer structure) may be melt-molded to obtain pellets made from the recovered composition, and then these pellets may be used in the manufacture of molded articles.

[0119] When the polypropylene content is high in the multilayer film, vapor-deposited multilayer film, or multilayer structure of the present invention, the recovered composition is particularly useful as a recycled material. Similarly, when the polypropylene content is high in the multilayer film, vapor-deposited multilayer film, or multilayer structure of the present invention, recycling can be efficiently carried out by the recycling method described above.

[0120] 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.

[0121] [Production Example 1] As the copolymer (y1), a partially saponified EVA "Mersen™ MX13" manufactured by Tosoh Corporation (ethylene unit content (Et) 92.6 mol%, vinyl acetate unit content (VAc) 6.8 mol%, vinyl alcohol unit content (VOH) 0.6 mol%, degree of saponification (DH) 8.1 mol%, MFR (190°C, 2.16 kg load) 2.0 g / 10 min, melting point 98°C) was prepared. As the tackifier (y2), an alicyclic hydrocarbon resin (product name "Alcon P-125"), which is a hydrogenated petroleum resin, manufactured by Arakawa Chemical Industries, Ltd. was prepared. 20 parts by mass of the above tackifier (y2) were added to 100 parts by mass of the above copolymer (y1) and mixed in a tumbler mixer. The obtained mixture was kneaded and granulated at 180°C using a twin-screw extruder with D = 25 mm (L / D = 30) to obtain an adhesive composition.

[0122] [Production Example 2] An adhesive composition was obtained in the same manner as in Production Example 1, except that the copolymer (y1) used was a partially saponified EVA "Mersen (trademark) H3051R" manufactured by Tosoh Corporation (ethylene unit content 88.9 mol%, vinyl acetate unit content 7.1 mol%, vinyl alcohol unit content 4.0 mol%, degree of saponification 36.0 mol%, MFR (190°C, 2.16 kg load) 5.5 g / 10 min, melting point 77°C).

[0123] [Production Example 3] An adhesive composition was obtained in the same manner as in Production Example 1, except that the copolymer (y1) used was a partially saponified EVA "Mersen (trademark) H6051K" manufactured by Tosoh Corporation (ethylene unit content 88.8 mol%, vinyl acetate unit content 0.3 mol%, vinyl alcohol unit content 10.9 mol%, degree of saponification 97.3 mol%, MFR (190°C, 2.16 kg load) 6.2 g / 10 min, melting point 110°C).

[0124] [Production Example 4] Partially saponified EVA used in Production Example 1 and ethylene vinyl acetate copolymer "Evaflex (trademark) EV270" manufactured by Mitsui Dow Polychemical Co., Ltd. (ethylene unit content 88.9 mol%, vinyl acetate unit content 11.1 mol%, vinyl alcohol unit content 0 mol%, degree of saponification 0 mol%, MFR (190°C, 2.16 kg load) 1.0 g / 10 min, density 0.95 g / cm³ ３ The mixture was added to a tumbler mixer in a mass ratio of 1:3 and mixed. The resulting mixture was kneaded and granulated at 180°C using a twin-screw extruder with a D of 25 mm (L / D = 30) to obtain a resin composition. The obtained resin composition had an ethylene unit content of 89.8 mol%, a vinyl acetate unit content of 10.0 mol%, a vinyl alcohol unit content of 0.2 mol%, and a degree of saponification of 2.0 mol%. An adhesive composition was obtained by the same method as in Production Example 1, except that the above resin composition was used as the copolymer (y1).

[0125] [Manufacturing Example 5] As the copolymer (y1), Mitsui Dow Polychemicals Ltd.'s ethylene vinyl acetate copolymer "Evaflex (trademark) EV270" (ethylene unit content 88.9 mol%, vinyl acetate unit content 11.1 mol%, vinyl alcohol unit content 0 mol%, degree of saponification 0 mol%, MFR (190°C, 2.16 kg load) 1.0 g / 10 min, density 0.95 g / cm³) ３ An adhesive composition was obtained using the same method as in Manufacturing Example 1, except that the following was used.

[0126] [Production Example 6] An adhesive composition was obtained using the same method as in Production Example 5, except that the amount of tackifier (y2) added was 10 parts by mass per 100 parts by mass of copolymer (y1).

[0127] [Example 1] (1) Preparation of multilayer film EVOH (ethylene (Et) unit content 44 mol%, degree of saponification (DH) 99.9 mol%, MFR (190°C, 2.16 kg load) 1.7 g / 10 min, melting point 165°C) was prepared as the material to form layer (X). The adhesive composition prepared in Production Example 1 was prepared as the material to form layer (Y). The random polypropylene (r-PP) "Novatec (trademark) FX4EA" manufactured by Nippon Polypropylene Co., Ltd. (MFR (230°C, 2.16 kg load) 5.3 g / 10 min, melting point 132°C, density 0.90 g / cm³) was prepared as the material to form layer (Z). ３The following materials were prepared. Using the above materials, a multilayer film with an average thickness and layer structure of X / Y / Z = 3 μm / 3 μm / 24 μm was fabricated using a three-layer cast co-extrusion film manufacturing facility. All extruders were single-screw extruders with D (mm) = 20, and full-flight screws with L / D = 25 and a compression ratio of 3.5 were used. A 300 mm wide feed block laminated T-die was used as the die. The temperature conditions at this time are shown below. The average thickness of the multilayer film was 30 μm, and the ratio of the average thickness of the layer mainly containing polypropylene to the average thickness of the multilayer film was 80%. Extrusion temperature of layer (X): Feed unit / compression unit / metering unit / adapter = 175 / 220 / 220 / 220°C Extrusion temperature of layer (Y): Feed unit / compression unit / metering unit / adapter = 120 / 220 / 220 / 220°C Extrusion temperature of layer (Z): Feed unit / compression unit / metering unit / adapter = 175 / 220 / 220 / 220°C Die temperature: 220°C

[0128] (2) Evaluation of interlayer adhesion of multilayer films The interlayer adhesion of the obtained multilayer films was evaluated. Specifically, the following procedure was followed. Strip-shaped test pieces measuring 200 mm in the longitudinal direction (MD direction) and 15 mm in the width direction (TD direction) were cut out. For the obtained test pieces, the edges of the interface between layer (X) and layer (Y) were peeled off, and the T-type peel strength (gf / 15 mm) of the adhesive strength between layer (X) and layer (Y) 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 taken on five test pieces (test pieces centered at 10%, 25%, 50%, 75%, and 90% of the width direction of the multilayer film, with one end of the width direction set to 0% and the other end set to 100%), and the average value was calculated. The results are shown in Table 1.

[0129] (3) Evaluation of the appearance characteristics of the multilayer film (image clarity measurement) The image clarity of the obtained multilayer film was measured at an optical comb width of 2.0 mm. Specifically, an image clarity measuring instrument (IC-T manufactured by Suga Test Instruments Co., Ltd.) was used, centered on the center position in the width direction of the multilayer film, and the average of three measurements was calculated. The results are shown in Table 1.

[0130] (4) Evaluation of the recyclability of the multilayer film (fish eye) The obtained multilayer film was crushed to a size of 4 mm square or less and mixed with random polypropylene "Novatec (trademark) FX4EA" manufactured by Nippon Polypropylene Co., Ltd. (MFR (230℃, 2.16 kg load) 5.3 g / 10 min, melting point 132℃, density 0.90 g / cm³) ３ ) and were dry-blended in a mass ratio (crushed material / random polypropylene) of 50 / 50 mass%, and a single-layer film was produced under the extrusion conditions shown below to obtain a single-layer film (recovered material) with an average thickness of 25 μm. The extruder was a single-screw extruder with D (mm) = 20, and a full-flight screw with L / D = 20 and a compression ratio of 3.5 was used. A 300 mm wide T-die was used as the die. The average thickness of the single-layer film was adjusted by appropriately changing the screw rotation speed and the take-up roll speed. The temperature conditions at this time are shown below. Extrusion temperature: feed section / compression section / metering section / adapter = 180 / 230 / 230 / 230℃ Die temperature: 230℃ Cooling roll temperature: 80℃ When preparing the obtained single-layer film (recovered material), a defect detector (Frontier Systems Co., Ltd. "FE Counter") was used to check for defects in a width of 0.08 m × length of 1 m (0.08 m ２ The number of fish eyes inside was counted. The results are shown in Table 1.

[0131] (5) Fabrication of vapor-deposited multilayer film A vapor-deposited multilayer film was fabricated by laminating an aluminum vapor-deposited layer (inorganic vapor-deposited layer (I)) with an average thickness of 50 nm onto the surface of layer (X) of the obtained multilayer film using a known vacuum deposition method.

[0132] (6) Measurement of oxygen permeation rate (OTR) of vapor-deposited multilayer film The vapor-deposited multilayer film obtained in (5) above was measured with layer (Z) as the oxygen supply side, in accordance with the method described in JIS K7126-2 (isobaric method; 2006). Specifically, using an oxygen permeation rate measuring device (MOCON OX-TRAN2 / 21 manufactured by Modern Control Co., Ltd.), the oxygen permeation rate (unit: cc / (m)) was measured under the conditions of a temperature of 20°C, humidity of 65% RH on the oxygen supply side, humidity of 65% RH on the carrier gas side, oxygen pressure of 1 atm, and carrier gas pressure of 1 atm. ２The day-atm (day) was measured. Nitrogen gas containing 2% by volume of hydrogen gas was used as the carrier gas. The results are shown in Table 1.

[0133] [Example 2] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that the adhesive composition prepared in Manufacturing Example 2 was used as the material for forming layer (Y). The evaluation results are shown in Table 1.

[0134] [Example 3] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that the adhesive composition prepared in Manufacturing Example 3 was used as the material for forming layer (Y). The evaluation results are shown in Table 1.

[0135] [Example 4] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that EVOH (ethylene unit content 27 mol%, degree of saponification 99.9 mol%, MFR (210°C, 2.16 kg load) 4.0 g / 10 min, melting point 190°C) was used as the material for forming layer (X). The evaluation results are shown in Table 1.

[0136] [Example 5] As the material for forming layer (Z), homopolypropylene (h-PP) "Novatec (trademark) FL203D" manufactured by Nippon Polypropylene Co., Ltd. was used (MFR (230℃, 2.16 kg load) 3.0 g / 10 min, melting point 160℃, density 0.90 g / cm³). ３ Multilayer films and vapor-deposited multilayer films were prepared and evaluated using the same method as in Example 1, except that the following was used. The evaluation results are shown in Table 1.

[0137] [Example 6] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that a partially saponified EVA "Mersen™ MX13" manufactured by Tosoh Corporation (ethylene unit content 92.6 mol%, vinyl acetate unit content 6.8 mol%, vinyl alcohol unit content 0.6 mol%, degree of saponification 8.1 mol%, MFR (190°C, 2.16 kg load) 2.0 g / 10 min, melting point 98°C) was used as the material for forming layer (Y). The evaluation results are shown in Table 1.

[0138] [Example 7] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that the adhesive composition prepared in Production Example 4 was used as the material for forming layer (Y). The evaluation results are shown in Table 1.

[0139] [Example 8] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that the adhesive composition prepared in Manufacturing Example 5 was used as the material for forming layer (Y). The evaluation results are shown in Table 1.

[0140] [Example 9] (Preparation of stretched multilayer film) An unstretched multilayer film was prepared using the same method as in Example 1, except that the average thickness of each layer was changed to X / Y / Z = 15 μm / 15 μm / 120 μm. A 5 cm section of the obtained unstretched multilayer film was cut in the MD direction, and stretched five times in the MD direction at 80°C using an Eto biaxial stretcher to produce a stretched multilayer film having an average thickness and layer structure of X / Y / Z = 3 μm / 3 μm / 24 μm.

[0141] Vapor-deposited multilayer films were prepared using the same method as in Example 1, except that the stretched multilayer film described above was used as the multilayer film, and these films were evaluated. The evaluation results are shown in Table 1.

[0142] [Example 10] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that EVOH described in Example 4 was used as the material for forming layer (X) and the adhesive composition prepared in Production Example 5 was used as the material for forming layer (Y). The results are shown in Table 1.

[0143] [Example 11] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that EVOH (ethylene unit content 38 mol%, degree of saponification 99.9 mol%, MFR (210°C, 2.16 kg load) 1.7 g / 10 min, melting point 172°C) was used as the material for forming layer (X), and the adhesive composition prepared in Production Example 5 was used as the material for forming layer (Y). The results are shown in Table 1.

[0144] [Example 12] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that the adhesive composition prepared in Manufacturing Example 6 was used as the material for forming layer (Y). The results are shown in Table 1.

[0145] [Example 13] A multilayer film and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 1, except that the adhesive composition prepared in Production Example 5 was used as the material for forming layer (Y), and homopolypropylene (h-PP) described in Example 5 was used as the material for forming layer (Z). The results are shown in Table 1.

[0146] [Example 14] A multilayer film (stretched multilayer film) and a vapor-deposited multilayer film were prepared and evaluated using the same method as in Example 9, except that the adhesive composition prepared in Production Example 5 was used as the material for forming layer (Y). The results are shown in Table 1.

[0147] [Comparative Example 1] As the material for forming layer (Y), maleic anhydride-modified polyethylene "Admer (trademark) NF518" manufactured by Mitsui Chemicals, Inc. (MFR (230℃, 2.16 kg load) 5.0 g / 10 min, density 0.89 g / cm³) ３ Multilayer films and vapor-deposited multilayer films were prepared and evaluated using the same method as in Example 1, except for the use of [specific material]. The evaluation results are shown in Table 1.

[0148] [Comparative Example 2] As the material for forming layer (Y), Mitsui Dow Polychemicals Ltd.'s ethylene vinyl acetate copolymer "Evaflex (trademark) EV270" was used (ethylene unit content 88.9 mol%, vinyl acetate unit content 11.1 mol%, vinyl alcohol unit content 0 mol%, degree of saponification 0 mol%, MFR (190°C, 2.16 kg load) 1.0 g / 10 min, density 0.95 g / cm³) ３ Multilayer films and vapor-deposited multilayer films were prepared and evaluated using the same method as in Example 1, except that the following was used. The evaluation results are shown in Table 1.

[0149]

[0150] As shown in Table 1, each of the multilayer films in Examples 1 to 14 received good evaluations for both appearance characteristics (imageability) and interlayer adhesion. Each of the multilayer films in Examples 1 to 14 also had high recyclability. Furthermore, each of the vapor-deposited multilayer films in Examples 1 to 14 exhibited high gas barrier properties.

Claims

1. A co-extruded multilayer film having layer (X) as the outermost layer, in which layers (X), (Y), and (Z) are directly laminated in this order, wherein layer (X) mainly contains an ethylene-vinyl alcohol copolymer (x) having an ethylene unit content of 20 to 59 mol% and a degree of saponification of 80 mol% or more, and layer (Y) mainly contains an ethylene-vinyl ester copolymer or its saponified product (y1) having an ethylene unit content of 60 to 99 mol% and a degree of saponification of 0 to 99.9 mol%, and when the degree of saponification of the ethylene-vinyl ester copolymer or its saponified product (y1) is 1 to 99.9 mol%, layer (Y) contains 30 parts by mass or less of a tackifier (y2) per 100 parts by mass of the ethylene-vinyl ester copolymer or its saponified product (y1), or does not contain a tackifier (y2). A multilayer film in which, when the degree of saponification of the ethylene-vinyl ester copolymer or its saponified product (y1) is less than 1 mol%, layer (Y) contains 1 to 30 parts by mass of a tackifier (y2) per 100 parts by mass of the ethylene-vinyl ester copolymer or its saponified product (y1), and layer (Z) contains polypropylene (z) as the main component.

2. The multilayer film according to claim 1, wherein polypropylene (z) is a random copolymer.

3. The multilayer film according to claim 1 or 2, wherein the average thickness is 300 μm or less, and the average thickness of layer (X) is 30 μm or less.

4. The multilayer film according to claim 1 or 2, wherein the average thickness is 300 μm or less, and the average thickness of layer (X) is less than 20 μm.

5. The multilayer film according to claim 1 or 2, wherein the tackifier (y2) is at least one selected from the group consisting of petroleum resin, terpene resin, and rosin resin.

6. The multilayer film according to claim 1 or 2, which is an unstretched film.

7. The multilayer film according to claim 1 or 2, which is a stretched film stretched by at least three times and less than twelve times in at least one axial direction.

8. A vapor-deposited multilayer film comprising a multilayer film according to claim 1, and an inorganic vapor-deposited layer (I) laminated on the exposed surface side of layer (X), which is a metal vapor-deposited layer mainly composed of aluminum or an inorganic oxide vapor-deposited layer mainly composed of alumina or silica.

9. A multilayer structure comprising a multilayer film according to claim 1 or a vapor-deposited multilayer film according to claim 8, and at least one layer (R) laminated on the multilayer film or the vapor-deposited multilayer film, the layer mainly composed of a thermoplastic resin (r).

10. The multilayer structure according to claim 9, wherein the thermoplastic resin (r) is polypropylene.

11. The multilayer structure according to claim 10, wherein the polypropylene content is 80% by mass or more.

12. A packaging material having the multilayer film described in claim 1 or the vapor-deposited multilayer film described in claim 8.

13. A recovery composition comprising a recovered multilayer film according to claim 1 or a recovered vapor-deposited multilayer film according to claim 8.

14. A recycling method comprising the steps of obtaining crushed material by crushing the multilayer film described in claim 1 or the vapor-deposited multilayer film described in claim 8, and melt-molding a composition containing the crushed material.

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