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

Abstract

The present invention provides: a vapor-deposited multilayer film which has high oxygen barrier properties and high water vapor barrier properties, and has sufficient oxygen barrier properties even after a bending treatment; and the like. Provided is a vapor-deposited multilayer film comprising: a multilayer film in which a layer (A), as the outermost layer, a layer (B), and a layer (C) are stacked in this order; and a vapor-deposited inorganic layer (I) stacked on the exposed surface side of the layer (A). The vapor-deposited inorganic layer (I) is a vapor-deposited metal layer that is mainly composed of aluminum, or a vapor-deposited inorganic oxide layer that is mainly composed of alumina or silica. The layer (A) contains, as a main component, an ethylene-vinyl alcohol copolymer (a) that has an ethylene unit content of 36-60 mol%; the layer (B) contains, as a main component, an ethylene-vinyl alcohol copolymer (b) that has an ethylene unit content of 20-35 mol%; and the layer (C) contains a polyethylene or a polypropylene as a main component. The average thickness of the multilayer film is 300 µm or less.

Description

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

[0001] The present invention relates to a vapor-deposited multilayer film, a multilayer structure, a packaging material, a recovered composition, and a recycling method.

[0002] Packaging materials for long-term storage of foods and other foods often require various barrier properties, such as oxygen barrier and water vapor barrier properties. Widely used barrier layers include vapor-deposited layers of metals such as aluminum, and vapor-deposited layers of inorganic oxides such as silicon oxide and aluminum oxide. Meanwhile, resin layers with oxygen barrier properties, such as vinyl alcohol polymers and polyvinylidene chloride, are also widely used. Vinyl alcohol polymers exhibit oxygen barrier properties through hydrogen bonding between hydroxyl groups in the molecules, resulting in crystallization and densification. Among these, ethylene-vinyl alcohol copolymers (hereinafter sometimes abbreviated as "EVOH") are suitable for melt molding due to their excellent thermal stability. For this reason, multilayer films with EVOH layers are widely used as barrier packaging materials. Patent Document 1 describes a vapor-deposited multilayer film in which an inorganic vapor-deposited layer is laminated on the surface of a polyolefin-based multilayer film, the outermost layer of which is EVOH. Because such films have excellent barrier properties against water vapor and oxygen and are suitable for recycling, they are expected to replace packaging materials that are not suitable for recycling, such as polyolefins and aluminum foils.

[0003] International Publication No. 2021 / 261560

[0004] There is a need for the development of vapor-deposited films with improved oxygen barrier properties and water vapor barrier properties for use as packaging materials, etc. In particular, powder products such as coffee and milk powder require extremely high oxygen barrier properties, and the barrier properties may not be sufficient simply by vapor-depositing aluminum onto an EVOH layer. In particular, when producing packaging materials of a predetermined shape from vapor-deposited films, the packaging materials are usually completed through processing steps including folding, etc. Furthermore, even the completed packaging materials may be bent during transportation, use, etc. However, conventional vapor-deposited films may not have sufficient oxygen barrier properties after being bent.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a vapor-deposited multilayer film that has high oxygen barrier property and water vapor barrier property and maintains sufficient oxygen barrier property even after bending treatment, as well as a multilayer structure, a packaging material, a recovered composition, and a recycling method that use such a vapor-deposited multilayer film.

[0006] The above-mentioned objects are achieved by providing: [1] a vapor-deposited multilayer film comprising a multilayer film having layer (A) as the outermost layer, and layer (A), layer (B), and layer (C) laminated in this order, and an inorganic vapor-deposited layer (I) laminated on the exposed surface of layer (A), which is 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, wherein layer (A) contains, as the main component, an ethylene-vinyl alcohol copolymer (a) having an ethylene unit content of 36 to 60 mol %, layer (B) contains, as the main component, an ethylene-vinyl alcohol copolymer (b) having an ethylene unit content of 20 to 35 mol %, and layer (C) contains, as the main component, polyethylene or polypropylene, and the multilayer film has an average thickness of 300 μm or less; [2] the vapor-deposited multilayer film of [1], in which layer (A) has an average thickness of 10 μm or less and layer (B) has an average thickness of 10 μm or less; [3] The vapor-deposited multilayer film of [1] or [2], wherein the multilayer film has at least one layer (X) containing a polyolefin as a main component laminated between the layer (A) and the layer (B); [4] The vapor-deposited multilayer film of [3], wherein the ratio of the total average thickness of the at least one layer (X) to the average thickness of the multilayer film is 10% or more; [5] The vapor-deposited multilayer film of [3] or [4], wherein at least one layer (X) contains a PCR material as a main component; [6] The vapor-deposited multilayer film of any of [1] to [5], wherein the ethylene-vinyl alcohol copolymer (a) has an ethylene unit content of 38 mol% or more and the ethylene-vinyl alcohol copolymer (b) has an ethylene unit content of 32 mol% or less; [7] The vapor-deposited multilayer film of any of [1] to [6], wherein the multilayer film has an adhesive resin layer (E) laminated between the layer (B) and the layer (C); [8] The vapor-deposited multilayer film of any of [1] to [7], wherein the multilayer film is an unstretched coextruded multilayer film; [9] The vapor-deposited multilayer film of any one of [1] to [7], wherein the multilayer film is a coextruded multilayer film stretched at least uniaxially;

[10] Layer (C) has a density of 0.930 g / cm ３ a polyethylene having a density of 0.925 g / cm3, wherein the multilayer film is laminated on the side of layer (C) opposite to layer (B); ３

[11] Any of the vapor-deposited multilayer films of [1] to [9], further comprising a layer (D) containing as a main component polyethylene, which is the following:

[11] Any of the vapor-deposited multilayer films of [1] to [9], wherein layer (C) contains as a main component homopolypropylene or random copolymer polypropylene, and the multilayer film further comprises a layer (D) containing as a main component random copolymer polypropylene or terpolymer polypropylene having a lower melting point than the main component of layer (C), laminated on the side of layer (C) opposite to layer (B);

[12] A multilayer structure comprising a vapor-deposited multilayer film of any of [1] to

[11] , and a film (R) having a layer containing as a main component polyethylene or polypropylene, laminated on the exposed surface of the inorganic vapor-deposited layer (I) of the vapor-deposited multilayer film;

[13] A packaging material comprising a vapor-deposited multilayer film of any of [1] to

[11] or the multilayer structure of

[12] ;

[14] A recovered composition comprising a recycled vapor-deposited multilayer film of any of [1] to

[11] or the multilayer structure of

[12] ;

[15] The object of the present invention is achieved by providing a recycling method comprising the steps of: crushing a vapor-deposited multilayer film of any one of [1] to

[11] or a multilayer structure of

[12] to obtain crushed material; and melt-molding a composition containing the crushed material.

[0007] The present invention can provide a vapor-deposited multilayer film that has high oxygen barrier property and water vapor barrier property and maintains sufficient oxygen barrier property even after bending treatment, as well as a multilayer structure, a packaging material, a recovered composition, and a recycling method that use such a vapor-deposited multilayer film.

[0008] In this specification, "major component" refers to the component with the highest content by mass. Unless otherwise specified, "average thickness" refers to the average value of thicknesses measured at any five locations. The "outermost layer" is not limited to the layer present on the front side, distinguishing between the front and back sides. In other words, the layer with the exposed surface is the outermost layer. A 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 more and B or less. In this specification, when describing a layer structure, " / " indicates that the layers are laminated directly, and " / / " indicates that the layers are laminated directly or via an adhesive layer.

[0009] Hereinafter, embodiments of the present invention will be described. Note that in the following description, specific materials (compounds, etc.) that exhibit specific functions may be exemplified, but the present invention is not limited to embodiments using such materials. Furthermore, the exemplified materials may be used alone or in combination, unless otherwise specified.

[0010] <Vapor-deposited multilayer film> The vapor-deposited multilayer film of the present invention comprises a multilayer film having layer (A) as the outermost layer, and layer (A), layer (B), and layer (C) laminated in this order, and inorganic vapor-deposited layer (I) laminated on the exposed surface of layer (A), which is a metal vapor-deposited layer containing aluminum as a main component or an inorganic oxide vapor-deposited layer containing alumina or silica as a main component, wherein layer (A) contains EVOH (a) as a main component having an ethylene unit content of 36 to 60 mol %, layer (B) contains EVOH (b) as a main component having an ethylene unit content of 20 to 35 mol %, and layer (C) contains polyethylene or polypropylene as a main component, and the average thickness of the multilayer film is 300 μm or less.

[0011] The vapor-deposited multilayer film of the present invention has high oxygen barrier property and water vapor barrier property, and maintains sufficient oxygen barrier property even after bending treatment. The reason why the vapor-deposited multilayer film of the present invention exhibits the above-mentioned effects is unclear, but the following reason is presumed. The vapor-deposited multilayer film has high water vapor barrier property due to the presence of layer (A) containing EVOH (a) as a main component with an ethylene unit content of 36 to 60 mol%, and high oxygen barrier property due to the presence of layer (B) containing EVOH (b) as a main component with an ethylene unit content of 20 to 35 mol%. Furthermore, the vapor-deposited multilayer film has an inorganic vapor-deposited layer (I) provided on the exposed surface of layer (A) in the multilayer film, and the strong adhesion between layer (A) containing EVOH (a) as a main component and inorganic vapor-deposited layer (I) allows the vapor-deposited multilayer film to maintain sufficient oxygen barrier property even after bending treatment.

[0012] Furthermore, the vapor-deposited multilayer film of the present invention has high oxygen barrier properties from the inorganic vapor-deposited layer (I) side when the side of the multilayer film on which the inorganic vapor-deposited layer (I) is provided is in a high-humidity environment. This is thought to be because the inorganic vapor-deposited layer (I) and layer (A) with high water vapor barrier properties are located in front of layer (B) with high oxygen barrier properties, and therefore water vapor is first sufficiently blocked by inorganic vapor-deposited layer (I) and layer (A), and the relative humidity of layer (B) decreases, allowing the oxygen barrier function to be fully exhibited.

[0013]

[0023] Hereinafter, an embodiment of the vapor-deposited multilayer film of the present invention will be described in detail. Hereinafter, the oxygen barrier property and the water vapor barrier property will be collectively referred to simply as "barrier property." The vapor-deposited multilayer film comprises a multilayer film and an inorganic vapor-deposited layer (I).

[0014] (Multilayer Film) The multilayer film has a layer structure in which layer (A) is the outermost layer, and layer (A), layer (B), and layer (C) are laminated in this order. The multilayer film may also include layers other than layer (A), layer (B), and layer (C). Layer (A) and layer (B) may be in direct contact with each other without any other layer therebetween, or another layer may be provided between layer (A) and layer (B). Layer (B) and layer (C) may be in direct contact with each other without any other layer therebetween, or another layer may be provided between layer (B) and layer (C). Layer (C) may or may not be the outermost layer on the other side. In other words, another layer may or may not be provided on the surface of layer (C) opposite layer (B).

[0015] (Layer (A)) Layer (A) is the outermost layer on one side of the multilayer film. Layer (A) contains, as a main component, EVOH (ethylene-vinyl alcohol copolymer) (a) having an ethylene unit content of 36 to 60 mol %.

[0016] EVOH (a) and EVOH (b) described below are polymers obtained by saponifying an ethylene-vinyl ester copolymer obtained by polymerizing ethylene and a vinyl ester. Examples of the vinyl ester include vinyl acetate, vinyl propionate, and vinyl pivalate, with vinyl acetate being preferred.

[0017] The ethylene unit content of EVOH (a) is 36 to 60 mol%. By ensuring that the ethylene unit content of EVOH (a) is 36 mol% or more, the water vapor barrier properties of the vapor-deposited multilayer film can be improved. Furthermore, the higher the ethylene unit content of EVOH (a), which is the main component of layer (A) located at the outermost layer, the more likely it is that curling of the multilayer film, as described below, will be suppressed. The lower limit of the ethylene unit content of EVOH (a) is preferably 38 mol%, more preferably 40 mol%, even more preferably 42 mol%, and may be 44 mol%, 46 mol%, or 48 mol%. On the other hand, by ensuring that the ethylene unit content of EVOH (a) is 60 mol% or less, the adhesion to the inorganic vapor-deposited layer (I) can be improved, and the oxygen barrier properties of the vapor-deposited multilayer film can be improved. The upper limit of the ethylene unit content of EVOH (a) is preferably 56 mol%, more preferably 52 mol%, even more preferably 50 mol%, and may be 48 mol%. The ethylene unit content is the content (mol %) of ethylene units relative to all monomer units constituting the EVOH.

[0018] The saponification degree of EVOH (a) is preferably 90 mol% or more. The saponification degree of EVOH means the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH. When the saponification degree of EVOH (a) is 90 mol% or more, the barrier properties of the vapor-deposited multilayer film can be further improved. The lower limit of the saponification degree of EVOH (a) is more preferably 95 mol%, even more preferably 98 mol%, and even more preferably 99 mol%. The upper limit of the saponification degree of EVOH (a) may be 100 mol% or 99.9 mol%. The ethylene unit content and saponification degree of EVOH are １ It is determined by H-NMR measurement.

[0019] EVOH (a) and EVOH (b) described later may contain other monomer units than ethylene units, vinyl alcohol units, and optionally remaining vinyl ester units, as long as the effects of the present invention are not impaired. Examples of monomers that provide the other monomer units include α-olefins such as propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and its salts; unsaturated monomers having an acrylic ester group; methacrylic acid and its salts; unsaturated monomers having a methacrylic 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 vinyl halides such as vinyl chloride and vinyl fluoride; vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate, 2,3-diacetoxy-1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids and salts or esters thereof such as maleic acid, itaconic acid and fumaric acid; vinylsilane compounds such as vinyltrimethoxysilane; isopropenyl acetate, 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane and 1,3-dibutyronyloxy-2-methylenepropane.

[0020] The EVOH (a) and the EVOH (b) described below may or may not be post-modified by a method such as urethanization, acetalization, cyanoethylation, or oxyalkylenation.

[0021] When the EVOH (a) has a modifying group such as another monomer unit, the EVOH (a) preferably has a structure (modifying group) represented by the following formula (I).

[0022]

[0023] (In formula (I), X is a hydrogen atom, a methyl group, or R ２ represents a group represented by —OH. １ and R ２ each independently represents 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.

[0024] X is preferably a hydrogen atom or R ２ is a group represented by —OH, and more preferably R ２ It is a group represented by —OH.

[0025] R １ or R ２ The alkylene and alkyleneoxy groups used as R may contain a hydroxy group, an alkoxy group, or a halogen atom. １ and R ２ is preferably an alkylene group or alkyleneoxy group having 1 to 5 carbon atoms, and more preferably an alkylene group or alkyleneoxy group having 1 to 3 carbon atoms.

[0026] Specific examples of the structure (modifying group) represented by formula (I) include structural units (modifying groups) represented by the following formulas (II), (III), and (IV), and among these, the structural unit represented by formula (II) is preferred.

[0027] (In formula (II), R ３ and R ４ each independently represents 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 ５has the same meaning as X in formula (I). ６ represents 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.

[0030]

[0031] (In formula (IV), R ７ and R ８ each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, or a hydroxy group. Some or all of the hydrogen atoms in the alkyl group and the cycloalkyl group may be substituted with a hydroxy group, an alkoxy group, or a halogen atom.

[0032] R in formula (I) １ is a single bond, and X is a hydroxymethyl group (R ３ , R ４ is preferably a hydrogen atom). Use of EVOH (a) having this modifying group tends to improve secondary processability such as stretchability and thermoformability without significantly deteriorating gas barrier property. When EVOH (a) contains the above modifying group, the lower limit of the content is preferably 0.1 mol%, more preferably 0.4 mol%, and even more preferably 1.0 mol%. On the other hand, from the viewpoint of improving gas barrier property, the upper limit of the content of the above modifying group is preferably 20 mol%, more preferably 10 mol%, even more preferably 8 mol%, and particularly preferably 5 mol%.

[0033] R in formula (I) １ is a hydroxymethylene group, X is a hydrogen atom (R ５ , R ６is a hydrogen atom). Use of EVOH (a) having this modifying group tends to improve secondary processability such as stretchability and thermoformability without significantly deteriorating gas barrier properties. When EVOH (a) contains the above modifying group, the lower limit of the 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 modifying group is preferably 20 mol%, more preferably 10 mol%, even more preferably 8 mol%, and particularly preferably 5 mol%, from the viewpoint of improving gas barrier properties.

[0034] R in formula (I) １ It is also preferred that R is a methylmethyleneoxy group and X is a hydrogen atom. By using EVOH (a) having such a modified group, secondary processability such as stretchability and thermoformability tends to be improved without significantly deteriorating the gas barrier property. In addition, the methylmethyleneoxy group has an oxygen atom bonded to a carbon atom of the main chain. That is, in formula (IV), R ７ , R ８ Preferably, one of the groups is a methyl group and the other is a hydrogen atom. When EVOH (a) contains the modifying group, the lower limit of the 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, from the viewpoint of improving gas barrier property, the upper limit of the content of the modifying group is preferably 20 mol%, more preferably 15 mol%, and even more preferably 10 mol%.

[0035] The upper limit of the content of other monomer units relative to the total monomer units of EVOH (a) 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 optional remaining vinyl ester units relative to the total monomer units of EVOH (a) is preferably 95 mol%, more preferably 97 mol%, and even more preferably 99 mol%. EVOH (a) may not have other monomer units.

[0036] The lower limit of the MFR (190°C, 2.16 kg load) of EVOH (a) is preferably 0.5 g / 10 min, more preferably 1.0 g / 10 min, and may be 3.0 g / 10 min or 5.0 g / 10 min. The upper limit of the MFR (190°C, 2.16 kg load) of EVOH (a) is preferably 12 g / 10 min, more preferably 8.0 g / 10 min. When the MFR of EVOH (a) is in the above range, it is possible to exhibit good melt moldability, etc. The MFR of EVOH is measured in accordance with JIS K7210-1 (2014).

[0037] The lower limit of the melting point of EVOH (a) is preferably 120° C., more preferably 130° C., even more preferably 140° C., and even more preferably 150° C. The upper limit of the melting point of EVOH (a) is preferably 190° C., more preferably 180° C., even more preferably 170° C., and may be 160° C. When the melting point of EVOH (a) is within the above range, good melt moldability can be exhibited.

[0038] EVOH (a) and EVOH (b) described later can be produced by a conventionally known method. These EVOHs may be commercially available products.

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

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

[0041] The upper limit of the average thickness of layer (A) is preferably 10 μm, more preferably 7 μm, even more preferably 5 μm, and may be 4 μm, 3 μm, or 2 μm. Having the average thickness of layer (A) equal to or less than the above upper limit makes it possible to reduce the thickness and weight of the vapor-deposited multilayer film and to suppress curling. The lower limit of the average thickness of layer (A) is preferably 0.1 μm, more preferably 0.5 μm, even more preferably 1 μm, and may be 1.5 μm or 2 μm. Having the average thickness of layer (A) equal to or greater than the above lower limit makes it possible to further improve the oxygen barrier property and water vapor barrier property.

[0042] The layer (A) may consist of a single layer or multiple layers. In one embodiment, the layer (A) is preferably a single layer. When multiple layers made of materials of the same composition are directly laminated, they are considered to be one layer. The same applies to other layers.

[0043] (Layer (B)) The layer (B) contains, as a main component, EVOH (ethylene-vinyl alcohol copolymer) (b) having an ethylene unit content of 20 to 35 mol %.

[0044] The ethylene unit content of EVOH (b) is 20 to 35 mol%. By having the ethylene unit content of EVOH (b) be 35 mol% or less, it is possible to improve the oxygen barrier properties of the vapor-deposited multilayer film. The upper limit of the ethylene unit content of EVOH (b) is preferably 32 mol%, more preferably 30 mol%, and may be 28 mol% or 26 mol%. On the other hand, by having the ethylene unit content of EVOH (b) be equal to or greater than the above lower limit, it is possible to improve the melt moldability. Furthermore, the higher the ethylene unit content of EVOH (b), the more likely it is that curling of the multilayer film, as described below, will be suppressed. The lower limit of the ethylene unit content of EVOH (b) is preferably 22 mol%, more preferably 24 mol%.

[0045] The saponification degree of EVOH (b) is preferably 90 mol% or more. When the saponification degree of EVOH (b) is 90 mol% or more, the barrier properties of the vapor-deposited multilayer film can be further improved. The lower limit of the saponification degree of EVOH (b) is more preferably 95 mol%, even more preferably 98 mol%, and even more preferably 99 mol%. The upper limit of the saponification degree of EVOH (b) may be 100 mol% or 99.9 mol%.

[0046] The upper limit of the content of other monomer units (monomer units other than ethylene units, vinyl alcohol units, and optionally remaining vinyl ester units) relative to the total monomer units of EVOH (b) 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 remaining vinyl ester units relative to the total monomer units of EVOH (b) is preferably 95 mol%, more preferably 97 mol%, and even more preferably 99 mol%. EVOH (b) may not have other monomer units.

[0047] EVOH (b) may have the same modifying group as EVOH (a).

[0048] The lower limit of the MFR (190°C, 2.16 kg load) of EVOH (b) is preferably 0.5 g / 10 min, more preferably 1.0 g / 10 min, and may be 2.0 g / 10 min. The upper limit of the MFR (190°C, 2.16 kg load) of EVOH (b) is preferably 10 g / 10 min, more preferably 7.0 g / 10 min, and may be 5.0 g / 10 min, 4.0 g / 10 min, or 3.0 g / 10 min. The lower limit of the MFR (210°C, 2.16 kg load) of EVOH (b) is preferably 1.0 g / 10 min, more preferably 2.0 g / 10 min, and may be 4.0 g / 10 min. The upper limit of the MFR (210°C, 2.16 kg load) of EVOH (b) is preferably 20 g / 10 min, more preferably 14.0 g / 10 min, and may be 10.0 g / 10 min, 8.0 g / 10 min, or 6.0 g / 10 min. When the MFR of EVOH (b) is in the above range, it is possible to exhibit good melt moldability, etc.

[0049] The lower limit of the melting point of EVOH (b) is preferably 160° C., more preferably 170° C., still more preferably 180° C., and may be 190° C. The upper limit of the melting point of EVOH (b) is preferably 230° C., more preferably 220° C., still more preferably 210° C., and may be 200° C. When the melting point of EVOH (b) is in the above range, good melt moldability can be exhibited.

[0050] The lower limit of the content of EVOH (b) in layer (B) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, and may be 95%, 99%, or 99.9% by mass. The upper limit of the content of EVOH (b) in layer (B) may be 100%, 99.99%, 99.9%, or 99% by mass.

[0051] Layer (B) may contain components other than EVOH (b). Examples of other components include boron compounds, carboxylic acids, phosphorus compounds, metal ions, resins other than EVOH (b), antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, and heat stabilizers. Layer (B) may contain two or more of these optional components.

[0052] The upper limit of the average thickness of layer (B) is preferably 10 μm, more preferably 7 μm, even more preferably 5 μm, and may be 4 μm, 3 μm, or 2 μm. Having the average thickness of layer (B) equal to or less than the above upper limit makes it possible to reduce the thickness and weight of the vapor-deposited multilayer film and to suppress curling. The lower limit of the average thickness of layer (B) is preferably 0.1 μm, more preferably 0.5 μm, even more preferably 1 μm, and may be 1.5 μm or 2 μm. Having the average thickness of layer (B) equal to or greater than the above lower limit makes it possible to further improve the oxygen barrier property, etc.

[0053] The layer (B) may consist of a single layer or multiple layers. In one embodiment, the layer (B) is preferably a single layer.

[0054] The lower limit of the ratio of the total average thickness of layers (A) and (B) to the average thickness of the multilayer film (the average thickness of the entire multilayer film) is preferably 5%, more preferably 8%, and even more preferably 10%. The barrier property improves as the ratio of the total average thickness of layers (A) and (B) increases. However, since both layers (A) and (B) contain EVOH as a main component and layer (A) is the outermost layer, an increase in the total average thickness ratio of layers (A) and (B) makes the multilayer film more prone to curling, as described below. Therefore, when the ratio of the total average thickness of layers (A) and (B) is equal to or greater than the above lower limit, providing layer (X), described below, is of great technical significance in suppressing curling. On the other hand, the upper limit of the ratio of the total average thickness of layers (A) and (B) to the average thickness of the multilayer film is preferably 25%, more preferably 20%, and even more preferably 15%. By setting the ratio of the total average thickness of the layer (A) to the layer (B) to be equal to or less than the upper limit, the occurrence of curling in the multilayer film tends to be reduced.

[0055] (Layer (C)) The layer (C) contains polyethylene or polypropylene as a main component.

[0056] Examples of polyethylene include high-density polyethylene, low-density polyethylene, very low-density polyethylene, linear low-density polyethylene, etc. The density of high-density polyethylene is, for example, 0.930 g / cm ３ 0.980g / cm or more ３ The density of low density polyethylene is, for example, 0.910 g / cm ３ 0.930g / cm or more ３ The density of ultra-low density polyethylene is, for example, 0.910 g / cm ３ The density of linear low density polyethylene is, for example, 0.910 g / cm ３ 0.925g / cm or more ３ is less than.

[0057] Examples of polypropylene include homopolypropylene, random copolymer polypropylene (e.g., polypropylene randomly copolymerized with ethylene), block copolymer polypropylene (e.g., block copolymer polypropylene having an ethylene block and a propylene block), and terpolymer polypropylene (e.g., terpolymer polypropylene randomly copolymerized with ethylene and butene).

[0058] The lower limit of the polyethylene or polypropylene content in layer (C) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, and may be 95%, 99%, or 99.9% by mass. The upper limit of the polyethylene or polypropylene content in layer (C) may be 100%, 99.99%, 99.9%, or 99% by mass.

[0059] Polyethylene and polypropylene can be produced by a conventionally known method, and commercially available polyethylene and polypropylene may also be used.

[0060] Layer (C) may contain components other than polyethylene or polypropylene. Examples of other components include antioxidants, UV absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, heat stabilizers, and resins other than polyethylene or polypropylene. Layer (C) may contain two or more of these optional components.

[0061] The upper limit of the average thickness of layer (C) is preferably 50 μm, more preferably 30 μm, even more preferably 20 μm, and even more preferably 10 μm. When the average thickness of layer (C) is equal to or less than the above upper limit, it is possible to reduce the thickness of the vapor-deposited multilayer film. The lower limit of the average thickness of layer (C) is preferably 1 μm, more preferably 3 μm, and even more preferably 6 μm. When the average thickness of layer (C) is equal to or more than the above lower limit, it is possible to further improve melt-formability, barrier properties, etc.

[0062] The layer (C) may consist of a single layer or multiple layers. In one embodiment, the layer (C) is preferably a single layer.

[0063] (Layer (D)) The multilayer film may have a layer (D) laminated on the side of layer (C) opposite to layer (B). Layer (D) preferably contains polyethylene or polypropylene as a main component. Specific examples of the polyethylene and polypropylene used in layer (D) are the same as the specific examples of the polyethylene and polypropylene used in layer (C) described above.

[0064] Layer (D) may be the outermost layer on the side opposite to layer (A) in the multilayer film. Layer (D) may also function as a sealant layer (heat seal layer). In order for layer (D) to function effectively as a sealant layer, it is preferable that the main component of layer (D) be a resin having a lower melting point than the main component of layer (C). In addition, in terms of recyclability, it is preferable that the main component of layer (D) be the same type as the main component of layer (C). That is, it is preferable that the main components of layer (C) and layer (D) are both polyethylene or both polypropylene.

[0065] In one embodiment, the layer (C) has a density of 0.930 g / cm ３ The layer (D) contains polyethylene having a density of 0.925 g / cm3 as a main component. ３ The lower limit of the density of the polyethylene of the main component of layer (C) is 0.940 g / cm ３ , 0.950g / cm ３ or 0.960 g / cm ３ The upper limit of the density of the polyethylene that is the main component of the layer (C) is 0.975 g / cm ３ 0.970 g / cm ３ The lower limit of the density of the polyethylene that is the main component of the layer (D) is 0.890 g / cm ３ , 0.900g / cm ３ or 0.910 g / cm ３ The upper limit of the density of the polyethylene that is the main component of the layer (D) is 0.920 g / cm ３ may be.

[0066] The lower limit of the melting point of the polyethylene that is the main component of layer (C) may be 110°C, 120°C, or 130°C. The upper limit of the melting point of the polyethylene that is the main component of layer (C) may be 150°C, 140°C, or 135°C. The lower limit of the melting point of the polyethylene that is the main component of layer (D) may be 100°C, 110°C, or 115°C. The upper limit of the melting point of the polyethylene that is the main component of layer (D) may be 130°C, 125°C, or 120°C.

[0067] In another embodiment, it is preferred that layer (C) contains homopolypropylene or random copolymer polypropylene as a main component, and layer (D) contains random copolymer polypropylene or terpolymer polypropylene as a main component having a lower melting point than the main component of layer (C).

[0068] The lower limit of the melting point of the polypropylene that is the main component of layer (C) may be 150°C, 155°C, or 160°C. The upper limit of the melting point of the polypropylene that is the main component of layer (C) may be 190°C, 180°C, or 170°C. The lower limit of the melting point of the polypropylene that is the main component of layer (D) may be 90°C, 95°C, or 100°C. The upper limit of the melting point of the polypropylene that is the main component of layer (D) may be 130°C, 120°C, or 110°C.

[0069] The lower limit of the polyethylene or polypropylene content in layer (D) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, and may be 95%, 99%, or 99.9% by mass. The upper limit of the polyethylene or polypropylene content in layer (D) may be 100% by mass, or may be 99.99%, 99.9%, or 99% by mass. Layer (D) may contain one or more optional components similar to those exemplified in layer (C).

[0070] The upper limit of the average thickness of layer (D) is preferably 50 μm, more preferably 30 μm, even more preferably 20 μm, and even more preferably 10 μm. When the average thickness of layer (D) is equal to or less than the above upper limit, it is possible to reduce the thickness of the vapor-deposited multilayer film. The lower limit of the average thickness of layer (D) is preferably 1 μm, more preferably 3 μm, and even more preferably 5 μm. When the average thickness of layer (D) is equal to or more than the above lower limit, it is possible to achieve good heat-sealing properties when layer (D) functions as a sealant layer.

[0071] The layer (D) may consist of a single layer or multiple layers. In one embodiment, the layer (D) is preferably a single layer.

[0072] (Layer (E)) The multilayer film preferably has an adhesive resin layer (E) (hereinafter also referred to as "layer (E)") laminated between layer (B) and layer (C). By providing layer (E) between layer (B) and layer (C), the adhesion between the layers is increased, and as a result, various barrier properties, particularly the barrier properties after bending treatment, can be further improved.

[0073] Layer (E) usually contains an adhesive resin as a main component. The adhesive resin is not particularly limited as long as it is a resin having adhesive properties, and examples thereof include acid-modified polyolefins (carboxylic acid-modified polyolefins, sulfonic acid-modified polyolefins, etc.), epoxy-modified polyolefins, etc. The adhesive resin is preferably a thermoplastic resin. The adhesive resin is preferably an acid-modified polyolefin (acid-modified polyethylene, acid-modified polypropylene, etc.), more preferably acid-modified polyethylene or acid-modified polypropylene. The adhesive resin is also preferably a carboxylic acid-modified polyolefin, more preferably carboxylic acid-modified polyethylene or carboxylic acid-modified polypropylene.

[0074] The carboxylic acid-modified polyolefin may be a polyolefin having a carboxy group or an anhydride group thereof. The carboxylic acid-modified polyolefin (a polyolefin having a carboxy group or an anhydride group thereof) can be obtained, for example, by chemically bonding an ethylenically unsaturated carboxylic acid or an anhydride thereof to an unmodified polyolefin by an addition reaction, a graft reaction, or the like.

[0075] The unmodified polyolefin used in the production of the carboxylic acid-modified polyolefin is preferably polyethylene or polypropylene.

[0076] Examples of ethylenically unsaturated carboxylic acids and their anhydrides include monocarboxylic acids, monocarboxylic acid esters, dicarboxylic acids, dicarboxylic acid monoesters, dicarboxylic acid diesters, and dicarboxylic acid anhydrides. Specific examples include maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, maleic acid monomethyl ester, maleic acid monoethyl ester, maleic acid diethyl ester, and fumaric acid monomethyl ester. Among these, dicarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride are preferred, and maleic anhydride is more preferred. That is, the adhesive resin is also preferably a maleic anhydride-modified polyolefin, and more preferably a maleic anhydride-modified polyethylene or maleic anhydride-modified polypropylene.

[0077] Carboxylic acid-modified polyolefins can be obtained by introducing an ethylenically unsaturated carboxylic acid or its anhydride into an unmodified polyolefin by addition reaction or graft reaction in the presence of a solvent such as xylene and a catalyst such as peroxide. The lower limit of the amount of carboxylic acid or its anhydride added to or grafted onto the unmodified polyolefin (modification degree) is preferably 0.01% by mass, more preferably 0.02% by mass, based on the unmodified polyolefin. On the other hand, the upper limit of the amount of addition or grafting (modification degree) is preferably 15% by mass, more preferably 10% by mass, based on the unmodified polyolefin.

[0078] The content of the adhesive resin in Layer (E) is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and still more preferably 97% by mass or more and 100% by mass or less. Layer (E) may contain, as components other than the adhesive resin, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, heat stabilizers, resins other than the adhesive resin, and the like.

[0079] The lower limit of the average thickness of layer (E) is preferably 0.1 μm, more preferably 0.5 μm, and even more preferably 1 μm. When the average thickness of layer (E) is equal to or greater than the above lower limit, sufficient adhesiveness can be exhibited. The upper limit of the average thickness of layer (E) is preferably 10 μm, more preferably 5 μm, and even more preferably 3 μm. When the average thickness of layer (E) is equal to or less than the above upper limit, the thickness of the vapor-deposited multilayer film can be reduced.

[0080] (Layer (X)) The multilayer film preferably has at least one layer (X) containing a polyolefin as a main component laminated between layer (A) and layer (B). In a multilayer film, when layer (A), which is one of the outermost layers, and layer (B) are directly laminated, layers (A) and (B) containing EVOH as a main component are unevenly distributed on one side, which makes the film prone to curling. A multilayer film prone to curling is undesirable from the standpoint of handleability, etc. In contrast, by interposing at least one layer (X) between layer (A) and layer (B), the uneven distribution of the layer containing EVOH as a main component is alleviated, and curling can be suppressed.

[0081] Examples of the polyolefin that is the main component of the layer (X) include the above-mentioned polyethylene and polypropylene, as well as polybutene and polypentene, and may be modified polyolefins, such as the above-mentioned acid-modified polyolefins.

[0082] The layer (X) may include, for example, a layer (X1) containing polyethylene or polypropylene as a main component. Specific examples of the material composition (types and contents of polyethylene, polypropylene, and optional components) constituting the layer (X1) are the same as the specific examples of the material composition constituting the layer (C) described above. For example, polyethylene as the main component of the layer (X1) may be polyethylene having a density of 0.930 g / cm ３ For example, the polypropylene that is the main component of the layer (X1) is preferably a polypropylene having a melting point of 130° C. or higher. By using a polyolefin having a relatively high density or melting point for the layer (X1), the mechanical strength can be increased and curling can be further suppressed.

[0083] The lower limit of the average thickness of the layer (X1) is preferably 1 μm, more preferably 2 μm, and even more preferably 3 μm, and the upper limit of the average thickness of the layer (X1) is preferably 30 μm, more preferably 20 μm, more preferably 10 μm, and even more preferably 5 μm.

[0084] The layer (X) may include, for example, a layer (X2) containing an acid-modified polyolefin as a main component. Specific examples of the material composition constituting the layer (X2) are the same as the specific examples of the material composition constituting the layer (E) when the layer (E) contains an acid-modified polyolefin as a main component. The acid-modified polyolefin as a main component of the layer (X2) is preferably an acid-modified polyethylene or an acid-modified polypropylene.

[0085] The lower limit of the average thickness of the layer (X2) is preferably 0.1 μm, more preferably 0.5 μm, and even more preferably 1 μm, and the upper limit of the average thickness of the layer (X2) is preferably 10 μm, more preferably 5 μm, and even more preferably 3 μm.

[0086] The layer (X) may include, for example, a layer (X3) containing a PCR (post-consumer recycled resin) material as a main component. PCR materials are materials recycled from used products on the market. In some cases, a layer formed from a PCR material may emit an odor. Therefore, by providing such a layer (X3) between the highly barrier layer (A) and layer (B), odor emission from the layer (X3) is suppressed, allowing the PCR material to be effectively utilized. Even in the layer (X3) containing a PCR material as a main component, the main component is preferably polyethylene or polypropylene.

[0087] The lower limit of the polyethylene or polypropylene content in the layer (X3) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, and may be 95%, 97%, or 99% by mass. The upper limit of the polyethylene or polypropylene content in the layer (X3) may be 100%, 99%, 95%, or 90% by mass.

[0088] The lower limit of the average thickness of the layer (X3) is preferably 1 μm, more preferably 2 μm, and even more preferably 3 μm, and the upper limit of the average thickness of the layer (X3) is preferably 30 μm, more preferably 20 μm, more preferably 10 μm, and even more preferably 5 μm.

[0089] The layer (X) may consist of a single layer or multiple layers. In one embodiment, the layer (X) is preferably a multilayer. The layer (X) may have a multilayer structure (three-layer structure), such as X2 / X1 / X2 or X2 / X3 / X2. The layer (X) may also have a two-layer structure, such as X1 / X2.

[0090] The lower limit of the ratio of the total average thickness of at least one layer (X) to the average thickness of the multilayer film (the average thickness of the entire multilayer film) is preferably 10%, more preferably 20%, and even more preferably 25%. By providing a layer (X) of a relatively sufficient thickness between layers (A) and (B), each of which contains EVOH as a main component, the uneven distribution of the layer containing EVOH as a main component is particularly sufficiently alleviated, and curling can be further suppressed. The upper limit of the ratio of the total average thickness of at least one layer (X) to the average thickness of the multilayer film is preferably 80%, more preferably 60%, even more preferably 40%, and even more preferably 30%.

[0091] Furthermore, it is preferred that the ratio of the total average thickness of layers (A) and (B) to the average thickness of the multilayer film is 25% or less (even 20% or less or 15% or less), and that the ratio of the total average thickness of at least one layer (X) to the average thickness of the multilayer film is 10% or more (even 20% or more or 25% or more). In such cases, curling can be particularly sufficiently suppressed.

[0092] Alternatively, the ratio of the total average thickness of layers (A) and (B) to the average thickness of the multilayer film may be 5% or more (or even 8% or more or 10% or more), and the ratio of the total average thickness of at least one layer (X) to the average thickness of the multilayer film may be 10% or more (or even 20% or more or 25% or more). In such cases, the relatively thick layers (A) and (B) can exhibit particularly sufficient barrier properties, while suppressing curling, which is usually more likely to occur due to their relative thickness.

[0093] The lower limit of the ratio of the total average thickness of at least one layer (X) to the total average thickness of layer (A), layer (B), and at least one layer (X) (the average thickness of the laminated portion from layer (A) to layer (B)) is preferably 40%, more preferably 50%, and even more preferably 60%. Even in such cases, uneven distribution of layers containing EVOH as a main component is particularly sufficiently alleviated, and curling can be further suppressed. The upper limit of the ratio of the total average thickness of at least one layer (X) to the total average thickness of layer (A), layer (B), and at least one layer (X) is preferably 80%, more preferably 70%.

[0094] Furthermore, it is preferred that the ratio of the total average thickness of layers (A) and (B) to the average thickness of the multilayer film is 25% or less (even 20% or less or 15% or less), and that the ratio of the total average thickness of at least one layer (X) to the total average thickness of layers (A), (B) and at least one layer (X) is 40% or more (even 50% or more or 60% or more). In such cases, curling can be particularly sufficiently suppressed.

[0095] Alternatively, the ratio of the total average thickness of layers (A) and (B) to the average thickness of the multilayer film may be 5% or more (even 8% or more or 10% or more), and the ratio of the total average thickness of at least one layer (X) to the total average thickness of layers (A), (B) and at least one layer (X) may be 40% or more (even 50% or more or 60% or more). In such cases, the relatively thick layers (A) and (B) can exhibit particularly sufficient barrier properties, while suppressing curling, which is usually more likely to occur due to their relative thickness.

[0096] (Other Layers and Layer Structure in the Multilayer Film) The multilayer film may further have layers other than the layer (A), the layer (B), the layer (C), the layer (D), the layer (E), and the layer (X). Examples of such layers include other thermoplastic resin layers, adhesive layers, etc. It may be preferable that the multilayer film does not have any layers other than the layer (A), the layer (B), the layer (C), the layer (D), the layer (E), and the layer (X).

[0097] The upper limit of the average thickness of the multilayer film is 300 μm, preferably 200 μm, more preferably 100 μm, even more preferably 70 μm, and in some cases even more preferably 60 μm, 50 μm, or 40 μm. Having an average thickness of the multilayer film equal to or less than the above upper limit allows for the deposition multilayer film to be made thinner and for costs to be reduced. Furthermore, despite the use of such a thin multilayer film, the deposition multilayer film of the present invention can exhibit excellent barrier properties. 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 even more preferably 20 μm or 25 μm. Having an average thickness of the multilayer film equal to or greater than the above lower limit further enhances the barrier properties and also the oxygen barrier properties after bending treatment.

[0098] Examples of the layer structure of the multilayer film include A / B / C, A / B / C / D, A / B / E / C, A / B / E / C / D, A / X / B / C, A / X / B / C / D, A / X / B / E / C, A / X / B / E / C / D, A / X / / X / B / E / C, and A / X / / X / B / E / C / D. Note that A is layer (A), B is layer (B), C is layer (C), D is layer (D), E is layer (E), and X is layer (X). Examples of specific layer structures when layer (X) has a multilayer structure are as described above.

[0099] The multilayer film may be an unstretched film or a stretched film stretched at least uniaxially. When the multilayer film is an unstretched film, for example, when a layer (D) is provided, the layer (D) has an advantage that the layer (D) functions particularly effectively as a sealant layer.

[0100] When the multilayer film is a stretched film, the multilayer film may be a uniaxially stretched film or a biaxially stretched film. When the multilayer film is a stretched film, the barrier properties of the vapor-deposited multilayer film can be further improved. When the multilayer film is a stretched film, it is preferably stretched at least uniaxially by a factor of 2 or more but less than 12, and more preferably stretched at least uniaxially by a factor of 3 or more but less than 8.

[0101] The method for producing the multilayer film is not particularly limited, but a coextrusion method is preferred. That is, the multilayer film is preferably a coextruded multilayer film. By employing the coextrusion method, a multilayer film having good film properties such as barrier properties and flexibility can be produced with high productivity. Examples of the coextrusion method include coextrusion cast molding, coextrusion inflation molding, and coextrusion coating molding.

[0102] The multilayer film may be formed by laminating multiple films together. Laminating multiple films can be performed by a known method such as dry lamination. The adhesive used for dry lamination is preferably a two-component reactive polyurethane adhesive in which a polyisocyanate component and a polyol component are mixed and reacted. An adhesive layer may be formed between the laminated films. Some or all of the multiple films constituting the multilayer film may be co-extruded multilayer films. The films constituting the multilayer film may be unstretched films or stretched films. The multilayer film may be, for example, a laminate of an unstretched co-extruded multilayer film and a stretched co-extruded multilayer film.

[0103] (Inorganic Vapor Deposition Layer (I)) The vapor-deposited multilayer film of the present invention is obtained by laminating an inorganic vapor-deposited layer (I) on the exposed surface of layer (A) in the above-described multilayer film. In other words, the above-described multilayer film may be a substrate film on which vapor deposition is performed. In this vapor-deposited multilayer film, the inorganic vapor-deposited layer (I) is usually laminated directly on the exposed surface of layer (A). The inorganic vapor-deposited layer (I) is a layer that has excellent barrier properties against oxygen, water vapor, and the like. Compared with ordinary thermoplastic resins, layer (A) has a higher affinity with metals and inorganic oxides, making it possible to form a dense, defect-free inorganic vapor-deposited layer (I). The obtained vapor-deposited multilayer film has good interlayer adhesion between layer (A) and inorganic vapor-deposited layer (I). Furthermore, because layer (A) and the like have barrier properties, deterioration of the barrier properties can be suppressed even when defects occur in the inorganic vapor-deposited layer (I) due to bending, etc.

[0104] The inorganic vapor-deposited layer (I) is either a metal vapor-deposited layer containing aluminum as a main component or an inorganic oxide vapor-deposited layer containing alumina or silica as a main component. A metal vapor-deposited layer is preferred when light-shielding properties are to be imparted, while an inorganic oxide vapor-deposited layer is preferred from the viewpoints of visibility of the contents as a packaging material, microwave suitability, and suppression of discoloration when the pulverized material is melt-molded.

[0105] The lower limit of the aluminum atom content in the metal vapor deposition layer is preferably 70 mass %, more preferably 90 mass %, and even more preferably 95 mass %, and the upper limit of the aluminum atom content in the metal vapor deposition layer may be 100 mass %.

[0106] In a metal vapor deposition layer containing aluminum as a main component, oxidation occurs irreversibly, and aluminum oxide may be partially contained. In a metal vapor deposition layer containing aluminum as a main component (inorganic vapor deposition layer (I)), the molar ratio of the oxygen atom content to the aluminum atom content (O mol / Al mol) is preferably 0.5 or less, more preferably 0.3 or less, and even more preferably 0.1 or less.

[0107] The lower limit of the alumina or silica content in the inorganic oxide vapor-deposited layer is preferably 70 mass %, more preferably 90 mass %, and even more preferably 95 mass %, and the upper limit of the alumina or silica content in the inorganic oxide vapor-deposited layer may be 100 mass %.

[0108] The upper limit of the average thickness of the inorganic vapor deposition 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 deposition layer (I) to the above upper limit or less, productivity can be increased, and in particular, when the inorganic vapor deposition layer (I) is an inorganic oxide vapor deposition layer, visibility, light transmittance, etc. can be improved. The lower limit of the average thickness of the inorganic vapor deposition 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 deposition layer (I) to the above lower limit or more, barrier properties can be further improved, and in particular, when the inorganic vapor deposition layer (I) is a metal vapor deposition layer, light blocking properties can be improved.

[0109] The inorganic vapor deposition layer (I) may be composed of a single layer or multiple layers, and in one embodiment, the inorganic vapor deposition layer (I) is preferably composed of a single layer.

[0110] The inorganic vapor deposition layer (I) can be formed by a known physical vapor deposition method or chemical vapor deposition method. Specific examples include vacuum deposition, sputtering, ion plating, ion beam mixing, plasma CVD, laser CVD, MO-CVD, and thermal CVD. Physical vapor deposition is preferred, with vacuum vapor deposition being particularly preferred. The upper limit of the surface temperature of layer (A) during the formation of inorganic vapor deposition 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 (A) during the formation of inorganic vapor deposition layer (I) is not particularly limited, but is preferably 0°C, more preferably 10°C, and even more preferably 20°C. The exposed surface of layer (A) may be plasma-treated before film formation. Known methods can be used for the plasma treatment, with atmospheric pressure plasma treatment being preferred. In atmospheric pressure plasma treatment, nitrogen, helium, neon, argon, krypton, xenon, radon, or the like is used as a discharge gas. Among these, nitrogen, helium, and argon are preferably used, and nitrogen is particularly preferred because it can reduce costs. A known protective layer or the like may be provided on the inorganic vapor deposition layer (I) to improve flex resistance.

[0111] (Other Layers and Layer Structure in Vapor-Deposited Multilayer Film) The vapor-deposited multilayer film may further have layers other than layer (A), layer (B), layer (C), layer (D), layer (E), layer (X), and inorganic vapor-deposited layer (I). Examples of such layers include other thermoplastic resin layers, adhesive layers, etc. It may be preferable that the vapor-deposited multilayer film does not have any layers other than layer (A), layer (B), layer (C), layer (D), layer (E), layer (X), and inorganic vapor-deposited layer (I).

[0112] 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 even more preferably 70 μm, 60 μm, 50 μm, or 40 μm. When the average thickness of the vapor-deposited multilayer film is equal to or less than the above upper limit, it is possible to achieve a thinner film. Furthermore, the vapor-deposited multilayer film of the present invention can exhibit excellent barrier properties despite being such a thin vapor-deposited multilayer film. 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 even more preferably 20 μm or 25 μm. When the average thickness of the vapor-deposited multilayer film is equal to or greater than the above lower limit, the barrier properties are further improved, and the oxygen barrier properties after bending treatment are also further improved.

[0113] Examples of layer structures of vapor-deposited multilayer films include I / A / B / C, I / A / B / C / D, I / A / B / E / C, I / A / B / E / C / D, I / A / X / B / C, I / A / X / B / C / D, I / A / X / B / E / C, I / A / X / B / E / C / D, I / A / X / / X / B / E / C, and I / A / X / / X / B / E / C / D. A represents layer (A), B represents layer (B), C represents layer (C), D represents layer (D), E represents layer (E), X represents layer (X), and I represents inorganic vapor-deposited layer (I). Specific examples of layer structures when layer (X) has a multilayer structure are as described above.

[0114] The vapor-deposited multilayer film of the present invention can be suitably used as a packaging material. The vapor-deposited multilayer film may also be used for purposes other than packaging.

[0115] <Multilayer Structure> The multilayer structure of the present invention comprises the above-described vapor-deposited multilayer film and a film (R).

[0116] (Film (R)) The film (R) is laminated directly or via another layer on the exposed surface of the inorganic vapor deposition layer (I) of the vapor-deposited multilayer film. By providing the film (R) on the exposed surface of the inorganic vapor deposition layer (I) of the vapor-deposited multilayer film, various functions such as design, durability (mechanical strength), and protection of the inorganic vapor deposition layer (I) can be imparted. In addition, the film (R) may be a layer that functions as a sealant layer.

[0117] The film (R) has a layer containing polyethylene or polypropylene as a main component. The film (R) may be a single-layer film consisting of one layer containing polyethylene or polypropylene as a main component, or may be a multilayer film formed by laminating multiple layers containing polyethylene or polypropylene as a main component. The film (R) may have a layer other than the layer containing polyethylene or polypropylene as a main component. In one embodiment, the film (R) may be a single-layer or multilayer film consisting only of a layer containing polyethylene or polypropylene as a main component.

[0118] Specific examples of the polyethylene and polypropylene used in the film (R) are the same as the specific examples of the polyethylene and polypropylene used in the layer (C) described above. The lower limit of the polyethylene or polypropylene content in the film (R) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, and may be 95%, 99%, or 99.9% by mass. The upper limit of the polyethylene or polypropylene content in the film (R) may be 100% by mass, or may be 99.99%, 99.9%, or 99% by mass. The film (R) may contain one or more optional components similar to those exemplified in the layer (C).

[0119] The film (R) may be an unstretched film or a stretched film stretched at least uniaxially. From the viewpoint of improving mechanical strength, a stretched film is preferable, and from the viewpoint of improving heat sealability, an unstretched film is preferable. When the film (R) is a stretched film, it is preferably stretched at least uniaxially by 2 times or more but less than 12 times. The film (R) may be a uniaxially stretched film or a biaxially stretched film. The film (R) can be produced by a conventionally known method.

[0120] The lower limit of the average thickness of the film (R) is preferably 5 μm, more preferably 10 μm, and even more preferably 20 μm. When the average thickness of the film (R) is equal to or greater than the above lower limit, it is possible to increase the mechanical strength of the multilayer structure. The upper limit of the average thickness of the film (R) is preferably 200 μm, more preferably 100 μm, even more preferably 50 μm, and even more preferably 30 μm. When the average thickness of the film (R) is equal to or less than the above upper limit, it is possible to reduce the thickness of the multilayer structure.

[0121] The method for laminating the film (R) onto the vapor-deposited multilayer film is not particularly limited, and can be performed by a known method such as dry lamination. The adhesive used for dry lamination is preferably a two-component reactive polyurethane adhesive in which a polyisocyanate component and a polyol component are mixed and reacted. 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 the inorganic vapor-deposited layer (I) with a topcoat agent (e.g., "MFB1002" manufactured by Michelman Co., Ltd. or "Takelac™ WPB-341" manufactured by Mitsui Chemicals, Inc.), and then laminate the film (R).

[0122] An adhesive layer may be formed between the vapor-deposited multilayer film and the film (R). The average thickness of the adhesive layer is, for example, preferably 0.5 to 5 μm, more preferably 1 to 3 μm.

[0123] (Sealant layer (S)) The multilayer structure of the present invention may further comprise a sealant layer (S) laminated on the side of the vapor-deposited multilayer film opposite to the side on which the film (R) is laminated. In particular, when the multilayer film is a stretched film, providing a separate sealant layer (S) allows the function of the sealant layer (S) to be effectively exhibited.

[0124] The sealant layer (S) is preferably a layer containing a polyolefin as a main component, and more preferably a layer containing polyethylene or polypropylene as a main component. In particular, it is preferable that the main component be a polyethylene or polypropylene having a relatively low density and / or a relatively low melting point, as exemplified as the main component of layer (D). That is, a preferred form of the polyethylene or polypropylene contained in the sealant layer (S) is a polyethylene or polypropylene having a density and / or melting point within a predetermined range, as exemplified as the main component of layer (D). For example, the sealant layer (S) may be a layer containing a linear low-density polyethylene as a main component.

[0125] The lower limit of the polyethylene or polypropylene content in the sealant layer (S) is preferably 70% by mass, more preferably 80% by mass, and even more preferably 90% by mass, and may be 95%, 99%, or 99.9% by mass. The upper limit of the polyethylene or polypropylene content in the sealant layer (S) may be 100% by mass, or may be 99.99%, 99.9%, or 99% by mass. The sealant layer (S) may contain one or more optional components similar to those exemplified in the layer (C).

[0126] From the viewpoint of heat sealing properties, the sealant layer (S) is preferably an unstretched layer. An unstretched film may also be used as the sealant layer (S).

[0127] The sealant layer (S) may consist of a single layer or multiple layers.

[0128] The lower limit of the average thickness of the sealant layer (S) is preferably 5 μm, more preferably 10 μm, and even more preferably 20 μm. When the average thickness of the sealant layer (S) is equal to or greater than the above lower limit, it is possible to improve heat sealability, etc. The upper limit of the average thickness of the sealant layer (S) is preferably 200 μm, more preferably 100 μm, and even more preferably 50 μm. When the average thickness of the sealant layer (S) is equal to or less than the above upper limit, it is possible to reduce the thickness of the multilayer structure, etc.

[0129] The method for laminating the sealant layer (S) on the vapor-deposited multilayer film is not particularly limited, and can be performed by known methods such as dry lamination, extrusion lamination, etc. The adhesive used for dry lamination is preferably a two-component reactive polyurethane adhesive in which a polyisocyanate component and a polyol component are mixed and reacted.

[0130] An adhesive layer may be formed between the vapor-deposited multilayer film and the sealant layer (S). The average thickness of the adhesive layer is, for example, preferably 0.5 to 5 μm, more preferably 1 to 3 μm.

[0131] (Other Layers and Layer Structures in the Multilayer Structure) The multilayer structure of the present invention may further include other layers as long as the effects of the present invention are not impaired. Examples of other layers include a printed layer, a metal foil layer, and other resin layers. However, it may be preferable that the multilayer structure of the present invention does not include any layers other than the layers constituting the vapor-deposited multilayer film, the film (R), the sealant layer (S), and the adhesive layer.

[0132] 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. When the average thickness is equal to or less than 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, thereby reducing 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.

[0133] In the multilayer structure of the present invention, from the viewpoint of recyclability, it is preferable that the content (content ratio) of polyethylene or polypropylene is high. From this viewpoint, it is preferable that the main components of layer (C), optional layer (D), optional layer (E), optional layer (X), film (R), and optional sealant layer (S) are all polyethylene (including modified polyethylene) or all polypropylene (including modified polypropylene). For example, the ratio of the total average thickness of layers mainly composed of polyethylene (including modified polyethylene) 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. Furthermore, the ratio of the total average thickness of layers mainly composed of polypropylene (including modified polypropylene) 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.

[0134] Examples of the layer structure of the multilayer structure of the present invention include R / / vapor-deposited multilayer film and R / / vapor-deposited multilayer film / / S. Here, R represents the film (R) and S represents the sealant layer (S). In the vapor-deposited multilayer film, the inorganic vapor-deposited layer (I) is located on the R side. Examples of specific layer structures of the vapor-deposited multilayer film are as described above.

[0135] The multilayer structure of the present invention can be suitably used as a packaging material. The multilayer structure may also be used for purposes other than packaging.

[0136] In the vapor-deposited multilayer film and multilayer structure of the present invention, the oxygen transmission rate measured in accordance with the method described in JIS K7126-2 (isobaric method; 2006), with the side of the multilayer film on which the inorganic vapor-deposited layer (I) is provided as the oxygen supply side, under conditions of a temperature of 20°C, a humidity of 85% RH on the oxygen supply side, a humidity of 0% RH on the carrier gas side, an oxygen pressure of 1 atmosphere, and a carrier gas pressure of 1 atmosphere, using nitrogen gas containing 2% by volume of hydrogen gas as the carrier gas, is 0.5 cc / (m ２ ·day·atm), and ２ ·day·atm), and more preferably less than 0.05 cc / (m ２The vapor-deposited multilayer film and multilayer structure of the present invention have high oxygen barrier properties from the inorganic vapor-deposited layer (I) side, particularly when the side on which the inorganic vapor-deposited layer (I) is provided is in a high-humidity environment, and are useful as packaging materials or other barrier materials that can be exposed to high-humidity environments.

[0137] <Packaging Material> The packaging material of the present invention comprises the vapor-deposited multilayer film of the present invention or the multilayer structure of the present invention. The packaging material may be made of the vapor-deposited multilayer film of the present invention or the 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 may be formed into a predetermined shape such as a bag. From the viewpoint of heat sealability, etc., it is preferable that the layer (D) or the sealant layer (S) is located as the outermost layer. Furthermore, for example, the unstretched film (R) located as the outermost layer may function as the sealant layer.

[0138] For example, in the case of a packaging material formed into a shape having an inside and an outside, such as a bag, the side on which the inorganic vapor deposition layer (I) is provided may be the outside relative to the multilayer film. The vapor-deposited multilayer film and multilayer structure of the present invention have high oxygen barrier properties from the inorganic vapor deposition layer (I) side, particularly when the side on which the inorganic vapor deposition layer (I) is provided is in a high-humidity environment. Therefore, in the case of a packaging material in which the side on which the inorganic vapor deposition layer (I) is provided is the outside relative to the multilayer film, the packaging material can effectively prevent oxygen and the like from penetrating into the interior, even in a high-humidity environment. On the other hand, the packaging material of the present invention may be a packaging material in which the side on which the inorganic vapor deposition layer (I) is provided is the inside relative to the multilayer film.

[0139] The packaging material of the present invention is used for packaging, for example, foods, beverages, medicines, medical equipment, machine parts, clothing, etc. In particular, the packaging material is preferably used in applications requiring barrier properties against water vapor and oxygen, and applications in which the interior of the packaging material is replaced with various functional gases.

[0140] <Recovered Composition and Recycling Method> It is preferable to reuse recovered materials (scrap) obtained by recovering end portions or defective products generated during the production, etc., of the vapor-deposited multilayer film or multilayer structure of the present invention. In other words, a recovered composition containing recovered materials of the vapor-deposited multilayer film or multilayer structure of the present invention is also a preferred embodiment of the present invention.

[0141] The recycling method of the present invention also includes a step of crushing the vapor-deposited multilayer film or multilayer structure of the present invention to obtain crushed material, and a step of melt-molding a composition containing the crushed material.

[0142] In the recycling method of the present invention, first, the recovered vapor-deposited multilayer film or multilayer structure (recovered vapor-deposited multilayer film or multilayer structure) is crushed. The crushed material obtained by crushing is mixed with other components as needed to form a recovered composition. The other components added to the crushed material are preferably polyolefins, more preferably polyethylene or polypropylene. The recovered composition may be in a crushed state or may be in a melted state.

[0143] The recovered composition (a composition containing the recovered crushed pieces of the deposited multilayer film or multilayer structure) may be directly melt-molded and used to produce a molded article. Alternatively, the recovered composition (a composition containing the recovered crushed pieces of the deposited multilayer film or multilayer structure) may be melt-molded to obtain pellets of the recovered composition, and the pellets may then be used to produce a molded article.

[0144] When the deposited multilayer film or multilayer structure of the present invention has a high polyethylene or polypropylene content, the recovered composition is particularly useful as a recycled material. Similarly, when the deposited multilayer film or multilayer structure of the present invention has a high polyethylene or polypropylene content, it can be efficiently recycled by the above-mentioned recycling method.

[0145] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0146] The materials used in the examples and comparative examples are as follows: EVOH (a) and EVOH (b) EVOH1: EVOH pellets, ethylene unit content 24 mol%, saponification degree 99 mol%, MFR (210°C, 2.16 kg load) 2.2 g / 10 min, melting point 195°C, density 1.22 g / cm ３ EVOH2: EVOH pellets, ethylene unit content 27 mol%, saponification degree 99 mol%, MFR (210°C, 2.16 kg load) 4.0 g / 10 min, melting point 190°C, density 1.21 g / cm ３ EVOH3: EVOH pellets, ethylene unit content 32 mol%, saponification degree 99 mol%, MFR (190°C, 2.16 kg load) 1.6 g / 10 min, melting point 183°C, density 1.19 g / cm ３ EVOH4: EVOH pellets, ethylene unit content 38 mol%, saponification degree 99 mol%, MFR (190°C, 2.16 kg load) 1.7 g / 10 min, melting point 172°C, density 1.17 g / cm ３ EVOH5: EVOH pellets, ethylene unit content 44 mol%, saponification degree 99 mol%, MFR (190°C, 2.16 kg load) 1.7 g / 10 min, melting point 165°C, density 1.14 g / cm ３ EVOH6: EVOH pellets, ethylene unit content 48 mol%, saponification degree 99 mol%, MFR (190°C, 2.16 kg load) 6.4 g / 10 min, melting point 157°C, density 1.12 g / cm ３

[0147] Polyolefin PE1: "ELITE (trademark) AT6900" (DOW, high-density polyethylene, MFR (190 ° C, 2.16 kg load) 1.2 g / 10 min, melting point 134 ° C, density 0.969 g / cm ３ ) PP1: "Novatec (trademark) PP EA7AD" (Japan Polypropylene Corporation, polypropylene, MFR (230 ° C, 2.16 kg load) 1.4 g / 10 min, melting point 165 ° C, density 0.90 g / cm ３ PE2: "Evolue™ SP1510" (Prime Polymer Co., Ltd., linear low-density polyethylene, MFR (190°C, 2.16 kg load) 1.0 g / 10 min, melting point 118°C, density 0.915 g / cm ３) PP2: "Adsyl 5C" (manufactured by Lyondell Basell, polypropylene, MFR (230°C, 2.16 kg load) 5.5 g / 10 min, melting point 105°C, density 0.90 g / cm ３ )

[0148] Adhesive resin MAhPE1: "Admer (trademark) NF518" (Mitsui Chemicals, Inc., maleic anhydride modified polyethylene, MFR (190 ° C, 2.16 kg load) 3.1 g / 10 min, melting point 121 ° C, density 0.91 g / cm ３ MAhPP1: "Admer (trademark) QB510" (manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified polypropylene, MFR (190°C, 2.16 kg load) 3.0 g / 10 min, melting point 160°C, density 0.90 g / cm ３ )

[0149] Film (R) R1: "Hibron (trademark) P" (Tokyo Printing Ink Co., Ltd., uniaxially oriented polyethylene film, density 0.95 g / cm ３ , average thickness 25 μm) R2: "Pylen (trademark) P2161" (manufactured by Toyobo Co., Ltd., biaxially oriented polypropylene film, density 0.91 g / cm ３ , average thickness 25 μm)

[0150] Sealant layer (S) S1: "TUX (trademark) TC-S" (manufactured by Mitsui Chemicals Tocello Co., Ltd., linear low-density polyethylene film, average thickness 30 μm)

[0151] Example 1 (Preparation of Multilayer Film (Polyethylene-Based Film)) Using the materials listed in Table 1, a multilayer film having the layer structure listed in Table 1 was prepared using a nine-kind, nine-layer cast coextrusion film-forming facility. All extruders were single-screw extruders with a D (mm) of 32 and a full-flight screw with an L / D of 28 and a compression ratio of 3.0. A 350 mm wide feedblock lamination type T-die was used as the die. The extrusion temperature was 220°C. Adjacent layers of the same material were considered as a single layer. That is, the multilayer film of Example 1 had an eight-layer structure with an average thickness of 30 μm, having a layer structure of A (2 μm) / X2 (2 μm) / X1 (4 μm) / X2 (2 μm) / B (2 μm) / E (2 μm) / C (8 μm) / D (8 μm).

[0152] (Preparation of Vapor-Deposited Multilayer Film) An aluminum vapor-deposited layer (inorganic vapor-deposited layer (I)) having an average thickness of 50 nm was laminated on the exposed surface of the layer (A) of the obtained multilayer film by a known vacuum deposition method to obtain a vapor-deposited multilayer film.

[0153] (Preparation of Multilayer Structure) An adhesive solution was prepared by mixing a two-component reactive polyurethane adhesive (24 parts by mass of "Takelac™ A-520" and 4 parts by mass of "Takenate™ A-50" manufactured by Mitsui Chemicals, Inc.) with 37 parts by mass of ethyl acetate. The adhesive solution was applied to the corona-treated surface of a uniaxially oriented polyethylene film (R1) using a wire bar so that the average thickness after drying would be 2 μm, and the film was dried at 100° C. for 5 minutes. Thereafter, the uniaxially oriented polyethylene film (R1) was laminated onto the exposed surface of the inorganic vapor-deposited layer (I) of the obtained vapor-deposited multilayer film, thereby obtaining a multilayer structure.

[0154] Examples 2 to 4, Comparative Examples 1 to 6 Vapor-deposited multilayer films and multilayer structures were obtained in the same manner as in Example 1, except that the materials used to prepare the multilayer films were changed as shown in Table 1.

[0155] [Example 5] (Preparation of multilayer film (polypropylene-based film)) Using each of the materials listed in Table 1, a multilayer film having the layer structure listed in Table 1 was prepared using a 9-kind, 9-layer cast co-extrusion film-forming facility. All extruders were single-screw extruders with D (mm) = 32, and full-flight screws with L / D = 28 and a compression ratio of 3.0 were used. A 350 mm wide feedblock lamination type T-die was used as the die. The extrusion temperature was 220°C.

[0156] (Preparation of Vapor-Deposited Multilayer Film) An aluminum vapor-deposited layer (inorganic vapor-deposited layer (I)) having an average thickness of 50 nm was laminated on the exposed surface of the layer (A) of the obtained multilayer film by a known vacuum deposition method to obtain a vapor-deposited multilayer film.

[0157] (Preparation of Multilayer Structure) A biaxially oriented polypropylene film (R2) was laminated on the exposed surface of the inorganic vapor-deposited layer (I) of the obtained vapor-deposited multilayer film by the dry lamination method described in Example 1 to obtain a multilayer structure.

[0158] [Example 6] (Production of multilayer film (uniaxially stretched polyethylene film)) Using each of the materials listed in Table 1, a multilayer film (total thickness 150 μm) was produced using a 9-kind, 9-layer cast co-extrusion film production facility, and then stretched 5 times in the machine direction to produce a multilayer film having the layer structure listed in Table 1. All extruders were single-screw extruders with D (mm) = 32, and full-flight screws with L / D = 28 and a compression ratio of 3.0 were used. A 350 mm wide feedblock lamination type T-die was used as the die. The extrusion temperature was 220°C. The stretching temperature was 120°C.

[0159] (Preparation of Vapor-Deposited Multilayer Film) An aluminum vapor-deposited layer (inorganic vapor-deposited layer (I)) having an average thickness of 50 nm was laminated on the exposed surface of the layer (A) of the obtained multilayer film by a known vacuum deposition method to obtain a vapor-deposited multilayer film.

[0160] (Preparation of multilayer structure) A biaxially oriented polyethylene film (R1) was laminated to the exposed surface of the inorganic vapor-deposited layer (I) in the obtained vapor-deposited multilayer film by the dry lamination method described in Example 1. Furthermore, a sealant layer (S1) was laminated to the exposed surface of the layer (D) in the obtained vapor-deposited multilayer film by the dry lamination method to obtain a multilayer structure. The average thickness of the adhesive layer between the layer (D) and the sealant layer (S1) was 2 μm.

[0161] Example 7 (Preparation of Multilayer Film a (Polyethylene-Based Film)) Using each of the materials PE1, MAhPE1, and EVOH1, multilayer film a was prepared using a three-kind, five-layer cast coextrusion film-forming facility. All extruders were single-screw extruders with a D (mm) of 32, and full-flight screws with an L / D of 28 and a compression ratio of 3.0 were used. A 350 mm wide feedblock lamination type T-die was used as the die. The extrusion temperature was 220°C. That is, multilayer film a had a five-layer structure with an average thickness of 26 μm, having a layer structure of PE1 (10 μm) / MAhPE1 (2 μm) / EVOH1 (2 μm) / MAhPE1 (2 μm) / PE1 (10 μm).

[0162] (Preparation of Multilayer Film b (Biaxially Stretched Polypropylene Film)) Using each of the materials PP1, MAhPP1, and EVOH6, a multilayer film (layer thickness 900 μm) was produced using a three-kind, three-layer cast coextrusion film production facility, and then stretched 5 times in the machine direction and then 9 times in the direction perpendicular to the machine direction to produce multilayer film b. Each extruder was a single-screw extruder with D (mm) = 32, and a full-flight screw with L / D = 28 and a compression ratio of 3.0 was used. A 350 mm wide feedblock lamination type T-die was used as the die. The extrusion temperature was 240°C. The stretching temperatures were 110°C and 160°C in the machine direction and perpendicular direction, respectively. Multilayer film b had a three-layer structure with an average thickness of 20 μm and a layer structure of EVOH1 (2 μm) / MAhPP1 (2 μm) / PP1 (16 μm).

[0163] (Preparation of Vapor-Deposited Multilayer Film b) An aluminum vapor-deposited layer (inorganic vapor-deposited layer (I)) having an average thickness of 50 nm was laminated on the exposed surface of Layer (A) in the obtained multilayer film b by a known vacuum deposition method to obtain Vapor-Deposited Multilayer Film b.

[0164] (Preparation of Multilayer Structure) An adhesive solution was prepared by mixing 24 parts by mass of a two-component reactive polyurethane adhesive (24 parts by mass of "Takelac™ A-520" and 4 parts by mass of "Takenate™ A-50" manufactured by Mitsui Chemicals, Inc.) with 37 parts by mass of ethyl acetate. The adhesive solution was applied to the corona-treated surface of a biaxially oriented polypropylene film (R2) using a wire bar to an average thickness after drying of 2 μm, and then dried at 100°C for 5 minutes. Thereafter, the biaxially oriented polypropylene film (R2) was laminated to the exposed surface of the inorganic vapor deposition layer (I) of the vapor-deposited multilayer film b. Furthermore, the adhesive solution was applied to the corona-treated surface of the obtained laminate opposite the biaxially oriented polypropylene film R2 using a wire bar to an average thickness after drying of 2 μm, and then dried at 100°C for 5 minutes. Thereafter, the corona-treated PE surface of multilayer film a was laminated to obtain a multilayer structure (R2 (25 μm) / adhesive (2 μm) / I / EVOH1 (2 μm) / MAhPP1 (2 μm) / PP1 (16 μm) / adhesive (2 μm) / PE1 (10 μm) / MAhPE1 (2 μm) / EVOH1 (2 μm) / MAhPE1 (2 μm) / PE1 (10 μm)) having an average thickness of 75 μm.

[0165] (Evaluation) Each of the obtained vapor-deposited multilayer films or multilayer structures was evaluated by the following method. Note that the degree of curling of the vapor-deposited multilayer film of Example 7 was not evaluated. The results are shown in Table 1.

[0166] (1) Oxygen Transmission Rate of Multilayer Structure The oxygen transmission rate of the multilayer structure was measured in accordance with the method described in JIS K7126-2 (isobaric method; 2006) with the film (R) as the oxygen supply side. Specifically, the oxygen transmission rate (unit: cc / (m)) was measured using an oxygen transmission amount measuring device ("MOCON OX-TRAN2 / 21" manufactured by Modern Control) under the conditions of a temperature of 20°C, a humidity of 85% RH on the oxygen supply side, a humidity of 0% RH on the carrier gas side, an oxygen pressure of 1 atmosphere, and a carrier gas pressure of 1 atmosphere. ２ The carrier gas used was nitrogen gas containing 2% by volume of hydrogen gas. (Criteria) A: 0.05 cc / (m ２ · day · atm) or less B: 0.05 cc / (m ２・day・atm) or more 0.1cc / (m ２ ・day・atm) C: 0.1cc / (m ２ ・day・atm) or more 0.5cc / (m ２ · day · atm) or less D: 0.5 cc / (m ２ ・day・atm) or more 1.0cc / (m ２ · day · atm) less than E: 1.0 cc / (m ２ ・day・atm) or more

[0167] (2) Oxygen transmission rate of multilayer structure after bending treatment The multilayer structure was subjected to bending at 23°C using a Gelbo flex tester in accordance with the method described in ASTM F392, and then the oxygen transmission rate was measured by the method described in (1) above, and evaluated according to the same criteria as in (1) above.

[0168] (3) Water Vapor Transmission Rate of Multilayer Structure The water vapor transmission rate (unit: g / (m)) of the multilayer structure was measured at 38°C and 90% RH in accordance with the method described in JIS K7129. ２ The measured value was 0.05 g / (m ２ ・day) or less B: 0.05 g / (m ２ ・day) or more 0.1g / (m ２ ・day) or less C: 0.1 g / (m ２ ・day) or more 0.5g / (m ２ ・day) or less D: 0.5 g / (m ２ ・day) or more 1.0g / (m ２ ・day) less than E: 1.0 g / (m ２ ・day) or more

[0169] (4) Degree of curling of vapor-deposited multilayer film The degree of curling of the vapor-deposited multilayer film was judged according to the following criteria: (Criteria) A: No curl B: Mild curl C: Large curl D: Severe curl

[0170]

[0171] As shown in Table 1, the multilayer structures of Examples 1 to 7 were evaluated as A to C in (1) oxygen transmission rate, (2) oxygen transmission rate after bending treatment, and (3) water vapor transmission rate, and thus had high oxygen barrier property and water vapor barrier property, and retained sufficient oxygen barrier property even after bending treatment. Furthermore, the vapor-deposited multilayer films of Examples 1 to 3, 5, and 6, which were provided with layer (X), also showed sufficient suppression of curling.

[0172] The vapor-deposited multilayer film and multilayer structure of the present invention can be suitably used as a packaging material, etc.

Claims

1. A vapor-deposited multilayer film comprising: a multilayer film having layer (A) as the outermost layer, and layer (A), layer (B), and layer (C) laminated in this order; and an inorganic vapor-deposited layer (I) laminated on the exposed surface of layer (A), which is a metal vapor-deposited layer mainly composed of aluminum or an inorganic oxide vapor-deposited layer mainly composed of alumina or silica, wherein layer (A) contains as its main component an ethylene-vinyl alcohol copolymer (a) having an ethylene unit content of 36 to 60 mol%, layer (B) contains as its main component an ethylene-vinyl alcohol copolymer (b) having an ethylene unit content of 20 to 35 mol%, and layer (C) contains as its main component polyethylene or polypropylene, and the average thickness of the multilayer film is 300 μm or less.

2. The vapor-deposited multilayer film according to claim 1, wherein the average thickness of layer (A) is 10 μm or less and the average thickness of layer (B) is 10 μm or less.

3. The vapor-deposited multilayer film according to claim 1 or 2, wherein the multilayer film has at least one layer (X) containing a polyolefin as a main component laminated between layer (A) and layer (B).

4. The vapor-deposited multilayer film according to claim 3, wherein the ratio of the total average thickness of at least one layer (X) to the average thickness of the multilayer film is 10% or more.

5. The vapor-deposited multilayer film according to claim 3, wherein at least one layer (X) comprises a layer containing a PCR material as a main component.

6. The vapor-deposited multilayer film according to claim 1 or 2, wherein the ethylene unit content of the ethylene-vinyl alcohol copolymer (a) is 38 mol% or more, and the ethylene unit content of the ethylene-vinyl alcohol copolymer (b) is 32 mol% or less.

7. The vapor-deposited multilayer film according to claim 1 or 2, which has an adhesive resin layer (E) laminated between layer (B) and layer (C).

8. The vapor-deposited multilayer film according to claim 1 or 2, wherein the multilayer film is an unstretched coextruded multilayer film.

9. The vapor-deposited multilayer film according to claim 1 or 2, wherein the multilayer film is a coextruded multilayer film stretched at least uniaxially.

10. Layer (C) has a density of 0.930 g / cm ３ a polyethylene having a density of 0.925 g / cm3 or more as a main component, and the multilayer film is laminated on the side of layer (C) opposite to layer (B); ３ The vapor-deposited multilayer film according to claim 1 or 2, further comprising a layer (D) containing, as a main component, polyethylene having the following structure:

11. A vapor-deposited multilayer film according to claim 1 or claim 2, wherein layer (C) contains homopolypropylene or random copolymer polypropylene as a main component, and the multilayer film further comprises layer (D) laminated on the side of layer (C) opposite layer (B) and containing as a main component a random copolymer polypropylene or terpolymer polypropylene having a lower melting point than the main component of layer (C).

12. A multilayer structure comprising the vapor-deposited multilayer film according to claim 1 and a film (R) having a layer containing polyethylene or polypropylene as a main component, laminated on the exposed surface side of the inorganic vapor-deposited layer (I) of the vapor-deposited multilayer film.

13. A packaging material comprising the vapor-deposited multilayer film of claim 1 or the multilayer structure of claim 12.

14. A recovered composition comprising a recovered vapor-deposited multilayer film according to claim 1 or a recovered multilayer structure according to claim 12.

15. A recycling method comprising the steps of crushing the vapor-deposited multilayer film according to claim 1 or the multilayer structure according to claim 12 to obtain crushed material, and melt-molding a composition containing the crushed material.

Images