Barrier film, laminate and packaging container

Abstract

To provide a barrier film having a stretched film including a polyethylene layer and a vapor-deposited film, which is excellent in gas barrier property and adhesion between the stretched film and the vapor-deposited film.SOLUTION: A barrier film includes at least a stretched film, a first vapor-deposited film, and a second vapor-deposited film in this order in a lamination direction, wherein the stretched film contains at least a polyethylene layer containing polyethylene as a main component, and a surface resin layer which contains a gas barrier resin as a main component or contains polyethylene and an adhesive resin, and the first vapor-deposited film is provided on the surface resin layer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a barrier film, a laminate, and a packaging container. [Background technology]

[0002] Packaging containers are used to store contents such as liquids and powders, etc. Packaging containers are made using a laminate including a base material and a heat-sealable layer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-55156 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have investigated the production of packaging containers using laminates comprising stretched polyethylene films as substrates. However, because stretched polyethylene films have poor gas barrier properties, such packaging containers do not have sufficient gas barrier properties. Therefore, the present inventors have investigated the use of barrier films comprising a single layer of vapor-deposited film on a stretched polyethylene film as a substrate. However, such barrier films still sometimes have insufficient gas barrier properties, and the adhesion between the stretched polyethylene film and the vapor-deposited film is insufficient. An object of the present disclosure is to provide a barrier film comprising a stretched film containing a polyethylene layer and a vapor-deposited film, which has excellent gas barrier properties and excellent adhesion between the stretched film and the vapor-deposited film. [Means for solving the problem]

[0005] One embodiment of the barrier film of the present disclosure comprises at least a stretched film, a first vapor-deposited film, and a second vapor-deposited film, in this order in the stacking direction, and the stretched film comprises at least a polyethylene layer containing polyethylene as a main component, and a surface resin layer containing a gas barrier resin as a main component or containing polyethylene and an adhesive resin, and the first vapor-deposited film is provided on the surface resin layer. [Effects of the Invention]

[0006] According to the present disclosure, there is provided a barrier film comprising a stretched film containing a polyethylene layer and a vapor-deposited film, the barrier film having excellent gas barrier properties and excellent adhesion between the stretched film and the vapor-deposited film. The barrier film is useful, for example, as a substrate for packaging materials for producing packaging containers having excellent gas barrier properties. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1A is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 1B] FIG. 1B is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 1C] FIG. 1C is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 2] FIG. 2 is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 3] FIG. 3 is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 4] FIG. 4 is a schematic cross-sectional view showing one embodiment of the laminate. [Figure 5] FIG. 5 is a schematic cross-sectional view showing one embodiment of the laminate. [Figure 6] FIG. 6 is a schematic cross-sectional view showing one embodiment of a laminate. [Figure 7] FIG. 7 is a perspective view showing one embodiment of a tube container comprising a tube container body including a laminate and a cap. [Figure 8] FIG. 8 is a cross-sectional view taken along line AA in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described in detail. For clarity of explanation, the drawings may show the width, thickness, shape, etc. of each layer more schematically than in the embodiments, but these are merely examples and do not limit the interpretation of the embodiments. In this specification and each drawing, elements similar to those already described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0009] In this specification, when multiple upper limit candidates and multiple lower limit candidates are listed for a certain parameter, the numerical range of the parameter may be constructed by combining any one upper limit candidate with any one lower limit candidate. Examples of such parameters include physical properties, component content, and layer thickness. As an example, the following statement will be explained: "Parameter B is preferably A1 or greater, more preferably A2 or greater, and even more preferably A3 or greater. Parameter B is preferably A4 or less, more preferably A5 or less, and even more preferably A6 or less." In this example, the numerical range of parameter B may be A1 or greater and A4 or less, A1 or greater and A5 or less, A1 or greater and A6 or less, A2 or greater and A4 or less, A2 or greater and A5 or less, A2 or greater and A6 or less, A3 or greater and A4 or less, A3 or greater and A5 or less, or A3 or greater and A6 or less.

[0010] In this specification, polyethylene refers to a polymer in which the content of ethylene-derived structural units in all repeating structural units is greater than 50 mol%. In this polymer, the content of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The content is measured by NMR.

[0011] In this specification, polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and an ethylenically unsaturated monomer other than ethylene. Examples of the ethylenically unsaturated monomer other than ethylene include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene; vinyl monomers, such as vinyl acetate and vinyl propionate; and (meth)acrylic acid esters, such as methyl (meth)acrylate and ethyl (meth)acrylate.

[0012] In this specification, examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer. From the viewpoint of reducing the environmental load, the polyethylene may be biomass-derived polyethylene (hereinafter also referred to as "biomass polyethylene") or mechanically or chemically recycled polyethylene (hereinafter also referred to as "recycled polyethylene").

[0013] In this specification, the density of polyethylene is as follows: The density of the high density polyethylene is preferably 0.945 g / cm 3 The upper limit of the density of high density polyethylene is, for example, 0.965 g / cm 3 and preferably 0.960 g / cm 3 The density of the medium density polyethylene is preferably 0.930 g / cm 3 Exceeds 0.945g / cm 3 The density of the low density polyethylene is preferably 0.860 g / cm or less. 3 More than 0.930g / cm 3 or less, more preferably 0.900 g / cm 3 More than 0.930g / cm 3The density of the linear low density polyethylene is preferably 0.860 g / cm 3 More than 0.930g / cm 3 or less, more preferably 0.900 g / cm 3 More than 0.930g / cm 3 In this specification, the density of polyethylene is measured in accordance with JIS K7112-2:2023 (density gradient tube method, 23°C).

[0014] Low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene using a high-pressure polymerization method (high-pressure low-density polyethylene).Linear low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene and a small amount of α-olefins using a polymerization method using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst.

[0015] Examples of linear low-density polyethylene include ethylene-α-olefin copolymers. Examples of the α-olefin include the above-mentioned α-olefins having from 3 to 20 carbon atoms, preferably α-olefins having from 3 to 8 carbon atoms, and more preferably α-olefins having from 4 to 8 carbon atoms. Examples of linear low-density polyethylene include ethylene-1-butene copolymer (C4-LLDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymer (C6-LLDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymer (C8-LLDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomer is not limited to the above-mentioned comonomers, and additional comonomers may be used. For example, linear low-density polyethylene produced using a metallocene catalyst is preferred.

[0016] Polyethylenes with different densities or branches can be obtained by appropriately selecting the polymerization method. For example, it is preferable to use a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as the polymerization catalyst, and carry out polymerization in one or more stages by any of gas phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization.

[0017] In this specification, from the viewpoint of film-forming ability and processability, the melt flow rate (MFR) of the polyethylene is preferably 0.1 g / 10 min or more, more preferably 0.2 g / 10 min or more, even more preferably 0.3 g / 10 min or more, particularly preferably 0.5 g / 10 min or more, and preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, particularly preferably 5 g / 10 min or less, for example, 0.1 g / 10 min or more and 30 g / 10 min or less. In this specification, the MFR of the polyethylene is measured by Method A in accordance with JIS K7210-1:2014, at a temperature of 190°C and a load of 2.16 kg.

[0018] In this specification, each of the components (for example, polyolefins such as polyethylene, α-olefins, resin materials such as gas barrier resins, adhesive resins, and additives) appearing in the following explanations may be used alone or in combination of two or more types.

[0019] In this specification, "film" and "sheet" may be referred to, but "film" and "sheet" are not distinguished from each other solely on the basis of the difference in name. In this specification, "multilayer" means two or more layers. In this specification, when adjacent layers constituting a film have the same resin composition and are indistinguishable from each other, the adjacent layers may be integrated to form a single layer.

[0020] In this specification, the term "major component" in a layer refers to a component whose content in the layer is greater than 50% by mass, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0021] [Barrier film] The barrier film of the present disclosure comprises at least A stretched film; a first vapor-deposited film; a second deposited film; are provided in this order in the stacking direction (hereinafter, also simply referred to as "provided in this order").

[0022] <Stretched film> The stretched film comprises at least a polyethylene layer containing polyethylene as a main component; a surface resin layer containing a gas barrier resin as a main component or containing polyethylene and an adhesive resin; Equipped with. The stretched film may comprise two or more polyethylene layers.

[0023] In one embodiment, the stretched film comprises at least a first surface resin layer containing polyethylene as a main component; a polyethylene intermediate layer containing polyethylene as a main component; a second surface resin layer containing a gas barrier resin as a main component or containing polyethylene and an adhesive resin; are provided in this order in the stacking direction. The stretched film may have two or more polyethylene intermediate layers.

[0024] In the following description, a surface resin layer containing a gas barrier resin as a main component will also be referred to as a "surface resin layer (G)," and a surface resin layer containing polyethylene and an adhesive resin will also be referred to as a "surface resin layer (AH)." In the following description, a stretched film having a surface resin layer (G) will also be referred to as a "stretched film of the first embodiment," and a stretched film having a surface resin layer (AH) will also be referred to as a "stretched film of the second embodiment."

[0025] The stretched film of the first aspect may further comprise an adhesive resin layer between the polyethylene layer and the surface resin layer (G). In one embodiment, the stretched film of the first aspect may comprise, in this order, a first polyethylene layer as the first surface resin layer, a second polyethylene layer, a third polyethylene layer, an adhesive resin layer, and a surface resin layer (G) as the second surface resin layer. Hereinafter, the stretched film of this embodiment will also be referred to as "stretched film α." The compositions of the first to third polyethylene layers may be the same as or different from one another. The thicknesses of the first to third polyethylene layers may be the same as or different from one another.

[0026] In one embodiment, the stretched film of the second aspect may include, in this order, a first polyethylene layer as a first surface resin layer, a second polyethylene layer, a third polyethylene layer, a fourth polyethylene layer, and a surface resin layer (AH) as a second surface resin layer. Hereinafter, the stretched film of this embodiment will also be referred to as "stretched film β." The compositions of the first to fourth polyethylene layers may be the same as or different from one another. The thicknesses of the first to fourth polyethylene layers may be the same as or different from one another.

[0027] The stretched film has a first surface and a second surface opposite to the first surface. The first surface resin layer constitutes the first surface of the stretched film. The second surface resin layer constitutes the second surface of the stretched film. The first vapor-deposited film is provided on the second surface of the stretched film.

[0028] The stretched film has a multilayer structure of two or more layers. The number of layers of the stretched film is two or more, preferably three or more, and preferably nine or fewer, more preferably seven or fewer, for example, two or more and nine or fewer layers. Specifically, the number of layers of the stretched film may be three, five, seven, or nine. The stretched film having a multilayer structure has an excellent balance of, for example, gas barrier properties, strength, rigidity, heat resistance, transparency, and printability.

[0029] The polyethylene content in the stretched film is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 75% by mass or more, and particularly preferably 80% by mass or more. A laminate (or packaging container) including such a stretched film has, for example, excellent recyclability.

[0030] A stretched film is a film that has been subjected to a stretching treatment. Stretching can improve, for example, the strength, rigidity, heat resistance, transparency, and printability of the film. The stretching treatment may be uniaxial or biaxial. The biaxial stretching treatment may be sequential biaxial stretching treatment using a tenter frame method or the like, or simultaneous biaxial stretching treatment. When stretching in the machine direction (film flow direction, MD direction), the stretching ratio is preferably 2 times or more, more preferably 3 times or more, and preferably 10 times or less, more preferably 7 times or less, for example, 2 times or more and 10 times or less. When stretching in the width direction (direction perpendicular to the MD direction, TD direction), the stretching ratio is preferably 2 times or more, more preferably 3 times or more, and preferably 10 times or less, more preferably 7 times or less, for example, 2 times or more and 10 times or less.

[0031] The stretched film is, for example, a uniaxially stretched film, specifically a film uniaxially stretched in the MD direction (MDO film), or a biaxially stretched film, specifically a film biaxially stretched in both the MD and TD directions.

[0032] The thickness of the stretched film is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, particularly preferably 40 μm or less, for example, 5 μm or more and 200 μm or less. Stretched films having a thickness equal to or greater than the lower limit exhibit, for example, excellent strength, rigidity, and heat resistance. Stretched films having a thickness equal to or less than the upper limit exhibit, for example, excellent processability. In this specification, the thickness of the film and each layer is the average value of thicknesses measured at 10 points in a scanning electron microscope (SEM) image obtained by observing a cross section perpendicular to the film surface with an SEM.

[0033] The stretched film can be produced, for example, by forming the materials constituting each layer into a laminated film, and then stretching the laminated film. Examples of the film-forming method include an inflation method and a T-die casting method, with the inflation method being preferred.

[0034] In one embodiment, the stretched film is a stretched film of a coextruded resin film. In one embodiment, the stretched film is a film obtained by co-extrusion in the lamination direction of a material constituting the polyethylene layer, and, if the stretched film has an adhesive resin layer, a material constituting the adhesive resin layer, and a material constituting the surface resin layer (G) or (AH), in this order, by an inflation method or the like, and then stretching the resulting laminated film.

[0035] In one embodiment, the stretched film is a film obtained by co-extrusion in the stacking direction by an inflation method or the like of a material constituting the first surface resin layer, a material constituting the polyethylene intermediate layer, and, if the stretched film has an adhesive resin layer, a material constituting the adhesive resin layer, and a material constituting the second surface resin layer, in this order, and then stretching the resulting laminated film.

[0036] The stretched film and the barrier film may be subjected to a surface treatment. Such a stretched film and a barrier film have, for example, excellent adhesion to other layers. Examples of the surface treatment method include physical treatment and chemical treatment. Examples of the physical treatment include corona treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment. Examples of the chemical treatment include oxidation treatment using chemicals.

[0037] <Polyethylene layer> The polyethylene layer is, for example, a polyethylene intermediate layer located between the first and second surface resin layers in the stretched film, and / or the first surface resin layer.

[0038] The polyethylene layer contains polyethylene as a main component. From the viewpoints of the strength and heat resistance of the stretched film, high-density polyethylene and medium-density polyethylene are preferred, and from the viewpoints of the film-forming and processability of the stretched film, linear low-density polyethylene and medium-density polyethylene are preferred.

[0039] From the viewpoint of heat resistance, the melting point (Tm) of the polyethylene contained in the polyethylene layer is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, and particularly preferably 120°C or higher, and preferably 140°C or lower, for example, 100°C or higher and 140°C or lower. In this specification, the Tm of various materials is the melting peak temperature obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012 (using test specimens conditioned according to 3.(2) (however, a cooling rate of 10°C / min)).

[0040] The polyethylene content in the polyethylene layer is preferably more than 50% by mass, 60% by mass or more, or 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The barrier film of the present disclosure can be suitably used as a substrate constituting packaging materials such as polyethylene-based mono-material packaging materials.

[0041] The polyethylene layer may contain a resin material other than polyethylene, such as polyolefins other than polyethylene, such as polypropylene, polyesters, polyamides, (meth)acrylic resins, vinyl resins, cellulose resins, and ionomer resins.

[0042] The polyethylene layer may contain additives such as crosslinkers, antioxidants, UV absorbers, light stabilizers, antiblocking agents, slip agents, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins.

[0043] In the stretched film of the first aspect, the polyethylene layer may further contain a compatibilizer. By containing a compatibilizer in the polyethylene layer, the mixability between the gas barrier resin and the polyethylene can be improved when the stretched film and the barrier film are recycled by heating and melting. This effectively prevents the physical properties of the polyethylene from deteriorating after recycling, and also effectively prevents the transparency of the polyethylene from deteriorating.

[0044] Examples of compatibilizers include acid-modified polyolefins, with acid-modified polyethylene being preferred from the viewpoint of recyclability. Examples of acid-modified polyolefins include polyolefins modified with unsaturated carboxylic acid compounds, particularly graft-modified polyolefins. Examples of unsaturated carboxylic acid compounds include unsaturated carboxylic acids such as maleic acid and fumaric acid, or their acid anhydrides, esters, or metal salts. Specific examples of compatibilizers include polyethylene modified with an unsaturated carboxylic acid compound, with maleic anhydride-modified polyethylene being more preferred.

[0045] When the polyethylene layer contains a compatibilizer, the content of the compatibilizer in the polyethylene layer is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, for example, 1% by mass or more and 25% by mass or less. When the stretched film has two or more polyethylene layers, at least one polyethylene layer may contain a compatibilizer. When the stretched film has two or more polyethylene layers, the basis for the content of the compatibilizer is the total mass of all polyethylene layers.

[0046] When the polyethylene layer contains a compatibilizer, the content of the compatibilizer in the polyethylene layer is preferably 10 parts by mass or more and 200 parts by mass or less per 100 parts by mass of the gas barrier resin in the stretched film. For example, when the gas barrier resin is an ethylene-vinyl alcohol copolymer, the content of the compatibilizer in the polyethylene layer is preferably 100 parts by mass or more and 200 parts by mass or less per 100 parts by mass of the ethylene-vinyl alcohol copolymer in the stretched film. For example, when the gas barrier resin is a polyamide, the content of the compatibilizer in the polyethylene layer is preferably 25 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the polyamide in the stretched film.

[0047] The thickness of the polyethylene layer in the stretched film is preferably 3 μm or more, more preferably 8 μm or more, even more preferably 13 μm or more, and preferably 180 μm or less, more preferably 80 μm or less, even more preferably 40 μm or less, particularly preferably 30 μm or less, for example, 3 μm or more and 180 μm or less. A stretched film comprising a polyethylene layer having a thickness equal to or greater than the lower limit exhibits, for example, excellent strength, rigidity, heat resistance, and recyclability. A stretched film comprising a polyethylene layer having a thickness equal to or less than the upper limit exhibits, for example, excellent processability. When a stretched film comprises two or more polyethylene layers, the above "thickness" refers to the sum of the thicknesses of the polyethylene layers.

[0048] The thickness of the polyethylene layer is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, and is preferably 98% or less, more preferably 94% or less, even more preferably 90% or less, for example, 40% or more and 98% or less, of the thickness of the stretched film. When the stretched film has two or more polyethylene layers, the above "thickness" means the total thickness of the polyethylene layers.

[0049] The stretched film may have one polyethylene layer or two or more polyethylene layers.

[0050] In a stretched film having two or more polyethylene layers, the density of each polyethylene layer may be the same or different. For example, the stretched film may have a density gradient between the polyethylene layers. A stretched film having a density gradient between the polyethylene layers is excellent in strength, rigidity, heat resistance, and stretchability of the film before stretching.

[0051] In a stretched film having a density gradient between each polyethylene layer, it is preferable that the absolute value of the density difference between any adjacent polyethylene layers is small. The absolute value of the density difference is, for example, 0.050 g / cm 3 or less, preferably 0.040 g / cm 3 or less, more preferably 0.030 g / cm 3or less, more preferably 0.020 g / cm 3 The following is true: Such a stretched film can effectively prevent, for example, delamination at the interface between each polyethylene layer. The density of the polyethylene layer is measured in accordance with JIS K7112-2:2023 (density gradient tube method, 23°C).

[0052] In one embodiment, the stretched film includes a polyethylene layer as the first surface resin layer. The first surface resin layer in the film before stretching treatment is, for example, a layer containing medium-density polyethylene, preferably a layer containing medium-density polyethylene as a main component, or a layer containing medium-density polyethylene and at least one selected from the group consisting of linear low-density polyethylene and high-density polyethylene.

[0053] The medium-density polyethylene content in the first surface resin layer of the film before stretching treatment is preferably 45% by mass or more, more preferably 55% by mass or more, even more preferably 65% ​​by mass or more, and is preferably 95% by mass or less, more preferably 85% by mass or less, even more preferably 75% by mass or less, for example, 45% by mass or more and 95% by mass or less.

[0054] The total content of linear low-density polyethylene and high-density polyethylene in the first surface resin layer of the film before stretching treatment is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 25% by mass or more, and is preferably 55% by mass or less, more preferably 45% by mass or less, even more preferably 35% by mass or less, for example, 5% by mass or more and 55% by mass or less.

[0055] The thickness of the first surface resin layer in the stretched film is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 1.5 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6 μm or less, for example, 0.5 μm or more and 10 μm or less. The thickness of the first surface resin layer is preferably 3% or more, more preferably 5% or more, even more preferably 8% or more, and preferably 35% or less, more preferably 30% or less, even more preferably 25% or less, for example, 3% or more and 35% or less, relative to the thickness of the stretched film.

[0056] The ratio of the thickness of the second surface resin layer to the thickness of the first surface resin layer is preferably 0.6 or more and 1.5 or less, from the viewpoint of symmetry of the stretched film and suppression of curling.

[0057] The film α1 and the stretched film α obtained by stretching the film α1 comprise, in this order, a first polyethylene layer as a first surface resin layer, a second polyethylene layer, a third polyethylene layer, an adhesive resin layer, and a surface resin layer (G) as a second surface resin layer.

[0058] The film β1 and the stretched film β obtained by stretching the film β1 comprise, in this order, a first polyethylene layer as a first surface resin layer, a second polyethylene layer, a third polyethylene layer, a fourth polyethylene layer, and a surface resin layer (AH) as a second surface resin layer.

[0059] In one embodiment of films α1 and β1, the first polyethylene layer contains medium-density polyethylene, the second polyethylene layer contains linear low-density polyethylene, and the third polyethylene layer contains linear low-density polyethylene as a main component. Such films and stretched films thereof have, for example, excellent processability and excellent interlayer adhesion strength between the polyethylene layers, effectively suppressing delamination. Stretched films with a high-density first polyethylene layer have, for example, excellent heat resistance and can suppress curling due to the difference in density between the first and second surface resin layers.

[0060] In one embodiment of films α1 and β1, the first polyethylene layer contains medium-density polyethylene and linear low-density polyethylene. Such films and stretched films thereof have, for example, excellent processability. In one embodiment of films α1 and β1, the first polyethylene layer contains medium-density polyethylene and high-density polyethylene. Such films and stretched films thereof have, for example, excellent heat resistance and can sufficiently suppress the occurrence of curling. Details of the first polyethylene layer are the same as those of the first surface resin layer described above.

[0061] In films α1 and β1, the second polyethylene layer is, for example, a layer containing linear low-density polyethylene, and preferably, from the viewpoint of rigidity, etc., it is a layer containing linear low-density polyethylene and medium-density polyethylene, or, from the viewpoint of extensibility, etc., it is a layer containing linear low-density polyethylene as a main component.

[0062] In the film β1, the fourth polyethylene layer is, for example, a layer containing linear low-density polyethylene, and is preferably a layer containing linear low-density polyethylene and medium-density polyethylene from the viewpoint of rigidity, etc., or a layer containing linear low-density polyethylene as a main component from the viewpoint of extensibility, etc.

[0063] The content of linear low-density polyethylene in the second polyethylene layer of film α1 and the second and fourth polyethylene layers of film β1 is preferably 35% by mass or more, more preferably 45% by mass or more, even more preferably 55% by mass or more, and preferably 85% by mass or less, more preferably 75% by mass or less, even more preferably 65% ​​by mass or less, for example, 35% by mass or more and 85% by mass or less.

[0064] The medium-density polyethylene content in the second polyethylene layer of film α1 and the second and fourth polyethylene layers of film β1 is preferably 15% by mass or more, more preferably 25% by mass or more, even more preferably 35% by mass or more, and preferably 65% ​​by mass or less, more preferably 55% by mass or less, even more preferably 45% by mass or less, for example, 15% by mass or more and 65% by mass or less.

[0065] In the films α1 and β1, the third polyethylene layer is, for example, a layer containing linear low-density polyethylene as a main component. In the film α1, the third polyethylene layer may further contain the above-mentioned compatibilizer.

[0066] In films α1 and β1, the content of linear low-density polyethylene in the third polyethylene layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 75% by mass or more. The content of linear low-density polyethylene in the third polyethylene layer is 100% by mass or less, or may be 99% by mass or less, 97% by mass or less, 95% by mass or less, or 90% by mass or less.

[0067] When the third polyethylene layer of film α1 contains a compatibilizer, the content of the compatibilizer in the third polyethylene layer is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, particularly preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, particularly preferably 25% by mass or less, for example, 1% by mass or more and 40% by mass or less.

[0068] The thickness of the second polyethylene layer of stretched film α and the second and fourth polyethylene layers of stretched film β is each independently, relative to the thickness of the stretched film, preferably at least 5%, more preferably at least 10%, even more preferably at least 15%, and preferably at most 35%, more preferably at most 30%, even more preferably at most 25%, for example at least 5% and at most 35%.

[0069] In the stretched films α and β, the thickness of the third polyethylene layer is preferably 30% or more, more preferably 35% or more, even more preferably 40% or more, and preferably 80% or less, more preferably 70% or less, even more preferably 60% or less, of the thickness of the stretched film, for example, 30% or more and 80% or less.

[0070] In the stretched film α, the thickness of the adhesive resin layer is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, and preferably 20% or less, more preferably 18% or less, even more preferably 15% or less, for example, 2% or more and 20% or less, relative to the thickness of the stretched film.

[0071] In the stretched film α, the ratio of the thickness of the adhesive resin layer to the thickness of the second polyethylene layer is preferably 0.6 or more and 1.5 or less, from the viewpoint of symmetry of the stretched film and suppression of curling.

[0072] In the stretched film α, the ratio of the thickness of the surface resin layer (G) to the thickness of the first polyethylene layer is preferably 0.6 or more and 1.5 or less, from the viewpoint of symmetry of the stretched film and suppression of curling.

[0073] In the stretched film β, the ratio of the thickness of the second polyethylene layer to the thickness of the fourth polyethylene layer is preferably 0.6 or more and 1.4 or less, more preferably 0.7 or more and 1.3 or less, even more preferably 0.8 or more and 1.2 or less, and particularly preferably 0.9 or more and 1.1 or less, from the viewpoints of symmetry of the stretched film and suppression of curling.

[0074] In the stretched film β, the ratio of the thickness of the surface resin layer (AH) to the thickness of the first polyethylene layer is preferably 0.6 or more and 1.4 or less, more preferably 0.7 or more and 1.3 or less, even more preferably 0.8 or more and 1.2 or less, and particularly preferably 0.9 or more and 1.1 or less, from the viewpoint of symmetry of the stretched film and suppression of curling.

[0075] The density relationship between the polyethylene layers in stretched films α and β is not particularly limited as long as it does not impair the stretchability of the film and the heat resistance, strength, rigidity, and interlayer adhesion of the stretched film. In one embodiment, stretched films α and β have a higher density of the second polyethylene layer than the density of the third polyethylene layer, and a higher density of the first polyethylene layer than the density of the second polyethylene layer. Such stretched films tend to have better heat resistance, strength, rigidity, and curl suppression. In one embodiment, stretched films α and β have a higher density of the second polyethylene layer than the density of the third polyethylene layer, and a lower density of the first polyethylene layer than the density of the second polyethylene layer. In one embodiment, stretched films α and β have a lower density of the second polyethylene layer than the density of the third polyethylene layer, and a higher density of the first polyethylene layer than the density of the second polyethylene layer.

[0076] In one embodiment, the stretched film comprises two or more polyethylene layers, an optional adhesive resin layer, and a surface resin layer (G) or (AH), in this order, and the density of the polyethylene layer located farthest from the surface resin layer (G) or (AH) is preferably higher than the density of the polyethylene layer located nearest to the surface resin layer (G) or (AH). Such a stretched film can, for example, suppress curling.

[0077] ≪Surface resin layer (G)≫ The surface resin layer (G) contains a gas barrier resin as a main component. A stretched film having the surface resin layer (G) has superior gas barrier properties (particularly oxygen barrier properties), heat resistance, and rigidity compared to conventional stretched polyethylene films. The surface resin layer (G) tends to have excellent surface smoothness. A vapor-deposited film provided on the surface of the surface resin layer (G) tends to have excellent adhesion to the surface resin layer (G), for example, and to exhibit good gas barrier properties.

[0078] A gas barrier resin is a resin that has the function of suppressing gas permeation. Examples of gas barrier resins include ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyamides, polyvinylidene chloride, polyesters, polyether polyols, polyester polyols, polyurethanes, polyacrylonitrile, and (meth)acrylic resins. Among these, from the viewpoints of gas barrier properties (particularly oxygen barrier properties), heat resistance, rigidity, etc., ethylene-vinyl alcohol copolymers, polyvinyl alcohol, and polyamides are preferred, ethylene-vinyl alcohol copolymers and polyamides are more preferred, and from the viewpoint of gas barrier properties, ethylene-vinyl alcohol copolymers are even more preferred.

[0079] Ethylene-vinyl alcohol copolymer (EVOH) can be obtained, for example, by copolymerizing ethylene with a vinyl ester monomer and then saponifying the copolymer. The copolymerization of ethylene with a vinyl ester monomer can be carried out by any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization. The EVOH may be modified by known methods, such as urethanization, acetalization, cyanoethylation, or oxyalkylenation.

[0080] Although vinyl acetate is generally used as the vinyl ester monomer, other vinyl ester monomers may also be used, such as aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, and vinyl versatate, and aromatic vinyl esters such as vinyl benzoate.

[0081] The content of ethylene-derived structural units in EVOH (ethylene content) is preferably 20 mol% or more, more preferably 25 mol% or more, of all repeating structural units, from the viewpoint of processability of the stretched film. The ethylene content in EVOH is preferably 60 mol% or less, more preferably 50 mol% or less, of all repeating structural units, from the viewpoint of heat resistance, oxygen barrier property, and water vapor barrier property of the barrier film. The ethylene content is, for example, 20 mol% or more and 60 mol% or less. The ethylene content is measured by NMR.

[0082] The average saponification degree of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. The average saponification degree is measured in accordance with JIS K6726:1994 (wherein EVOH is used as a solution uniformly dissolved in a water / methanol solvent).

[0083] From the viewpoint of heat resistance, the melting point (Tm) of EVOH is preferably 140°C or higher, more preferably 145°C or higher, even more preferably 150°C or higher, and is preferably 200°C or lower, more preferably 195°C or lower, even more preferably 190°C or lower, for example, 140°C or higher and 200°C or lower.

[0084] From the viewpoint of film-forming ability and processability, the MFR of EVOH is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, even more preferably 0.5 g / 10 min or more, and preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less, for example, 0.1 g / 10 min or more and 30 g / 10 min or less. The MFR of EVOH is measured by Method A in accordance with JIS K7210-1:2014 under conditions of a temperature of 190°C and a load of 2.16 kg. The measurement temperature may be 210°C depending on the melting point of the EVOH.

[0085] The average saponification degree of polyvinyl alcohol (PVA) is preferably 70 mol% or more, more preferably 75 mol% or more, even more preferably 80 mol% or more, and particularly preferably 85 mol% or more. The average saponification degree is measured in accordance with JIS K6726:1994.

[0086] Examples of polyamides include aliphatic polyamides and aromatic polyamides. The surface resin layer (G) may contain one type of polyamide or two or more types of polyamides. The surface resin layer (G) may contain one or two or more types of aliphatic polyamides. The surface resin layer (G) may contain one or two or more types of aromatic polyamides. The surface resin layer (G) may contain one or two or more types of aliphatic polyamides and one or two or more types of aromatic polyamides.

[0087] Examples of aliphatic polyamides include aliphatic homopolyamides and aliphatic copolyamides. In the following examples, polyamides are also referred to as "PA."

[0088] Specific examples of aliphatic homopolyamides include polycaprolactam or poly(6-aminocaproic acid) (PA6), polyenantholactam or poly(7-aminoenanthic acid) (PA7), polyundecane lactam or poly(11-aminoundecanoic acid) (PA11), polylauryllactam or poly(12-aminolauric acid) (PA12), polyhexamethylene adipamide (PA66), polytetramethylene dodecamide (PA412), polypentamethylene azelamide (PA59), polypentamethylene sebacamide (PA510), polypentamethylene dodecamide (PA512), polyhexamethylene azelamide (PA69), and polyhexamethylene sebacamide. Polyhexamethylene dodecamide (PA610), polyhexamethylene dodecamide (PA612), polynonamethylene adipamide (PA96), polynonamethylene azelamide (PA99), polynonamethylene sebacamide (PA910), polynonamethylene dodecamide (PA912), polydecamethylene adipamide (PA106), polydecamethylene azelamide (PA109), polydecamethylene decamide (PA1010), polydecamethylene dodecamide (PA1012), polydodecamethylene adipamide (PA126), polydodecamethylene azelamide (PA129), polydodecamethylene sebacamide (PA1210) and polydodecamethylene dodecamide (PA1212).

[0089] Specific examples of aliphatic copolymer polyamides include caprolactam / hexamethylenediaminoadipic acid copolymer (PA6 / 66), caprolactam / hexamethylenediaminoazelaic acid copolymer (PA6 / 69), caprolactam / hexamethylenediaminosebacic acid copolymer (PA6 / 610), caprolactam / hexamethylenediaminoundecanoic acid copolymer (PA6 / 611), caprolactam / hexamethylenediaminododecanoic acid copolymer (PA6 / 612), caprolactam / amino Examples include undecanoic acid copolymer (PA6 / 11), caprolactam / lauryllactam copolymer (PA6 / 12), caprolactam / hexamethylenediaminoadipic acid / lauryllactam copolymer (PA6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymer (PA6 / 66 / 610), and caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymer (PA6 / 66 / 612).

[0090] The aliphatic polyamide is preferably a crystalline aliphatic polyamide. Examples of the crystalline aliphatic polyamide include PA6, PA11, PA12, PA66, PA610, PA612, PA6 / 66, and PA6 / 66 / 12. The melting point (Tm) of the crystalline aliphatic polyamide is preferably 170°C or higher, more preferably 180°C or higher, even more preferably 190°C or higher, and preferably 300°C or lower, more preferably 270°C or lower, even more preferably 250°C or lower, even more preferably 240°C or lower, particularly preferably 230°C or lower, for example, 170°C or higher and 300°C or lower.

[0091] Examples of aromatic polyamides include semi-aromatic polyamides and wholly aromatic polyamides, with semi-aromatic polyamides being preferred. Semi-aromatic polyamides are polyamides having structural units derived from aromatic diamines and structural units derived from aliphatic dicarboxylic acids, or polyamides having structural units derived from aliphatic diamines and structural units derived from aromatic dicarboxylic acids. Examples of semi-aromatic polyamides include polyamides composed of aromatic diamines and aliphatic dicarboxylic acids, and polyamides composed of aliphatic diamines and aromatic dicarboxylic acids.

[0092] Examples of semi-aromatic polyamides include polyhexamethylene terephthalamide (PA6T), polyhexamethylene isophthalamide (PA6I), polynonamethylene terephthalamide (PA9T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (PA66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (PA66 / 6I), polyhexamethylene terephthalamide / polycaproamide copolymer (PA6T / 6), polyhexamethylene isophthalamide / polycaproamide copolymer (PA6I / 6), polyhexamethylene terephthalamide / poly Examples include dodecamide copolymer (PA6T / 12), polyhexamethylene isophthalamide / polyhexamethylene terephthalamide copolymer (PA6I / 6T), polyhexamethylene terephthalamide / poly(2-methylpentamethylene terephthalamide) copolymer (PA6T / M5T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (PA66 / 6T / 6I), polyhexamethylene adipamide / polycaproamide / polyhexamethylene isophthalamide copolymer (PA66 / 6 / 6I), and polymetaxylylene adipamide (PAMXD6). Among these, polymetaxylylene adipamide (PAMXD6) and polyhexamethylene isophthalamide / polyhexamethylene terephthalamide copolymer (PA6I / 6T) are preferred.

[0093] In one embodiment, the semi-aromatic polyamide is preferably a crystalline semi-aromatic polyamide. The melting point (Tm) of the crystalline semi-aromatic polyamide is preferably 190°C or higher, more preferably 200°C or higher, even more preferably 210°C or higher, and preferably 310°C or lower, more preferably 280°C or lower, even more preferably 250°C or lower, for example, 190°C or higher and 310°C or lower. Specific examples of the crystalline semi-aromatic polyamide include PA6T, PA9T, and PAMXD6.

[0094] The glass transition temperature (Tg) of the crystalline semi-aromatic polyamide is preferably 50°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher, and preferably 140°C or lower, more preferably 130°C or lower, even more preferably 120°C or lower, for example, 50°C or higher and 140°C or lower. The Tg may be, for example, lower than 110°C, lower than 100°C, or lower than 90°C. In this specification, Tg refers to the midpoint glass transition temperature obtained by differential scanning calorimetry (DSC) at a heating rate of 10°C / min in accordance with JIS K7121:2012 (using a test piece conditioned according to 3.(3)).

[0095] In one embodiment, the semi-aromatic polyamide is preferably an amorphous semi-aromatic polyamide, from the viewpoints of being able to form a surface resin layer excellent in surface smoothness and transparency, being able to exhibit high gas barrier properties when a vapor-deposited film is formed on the surface resin layer, etc. Specifically, PA6I / 6T is preferred as the amorphous semi-aromatic polyamide.

[0096] The amorphous polyamide refers to a polyamide that does not have a clear crystalline melting peak, specifically a polyamide that has no crystalline melting peak or a crystalline melting peak with a crystalline melting enthalpy ΔHm of 5 J / g or less, preferably 3 J / g or less, more preferably 1 J / g or less. The crystalline melting enthalpy is measured by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012 and JIS K7122:2012.

[0097] As the amorphous semi-aromatic polyamide, a semi-aromatic polyamide having two or more structural units derived from aromatic dicarboxylic acids is preferred, and a polyamide having, as the dicarboxylic acid component, structural units derived from isophthalic acid and structural units derived from terephthalic acid, and as the diamine component, structural units derived from aliphatic diamine (hereinafter also referred to as "polyamide (a)") is more preferred.

[0098] In the polyamide (a), the proportion of structural units derived from isophthalic acid is preferably 40 mol% to 98 mol%, more preferably 50 mol% to 80 mol%, of 100 mol% of structural units derived from dicarboxylic acids, and the proportion of structural units derived from terephthalic acid is preferably 2 mol% to 60 mol%, more preferably 20 mol% to 50 mol%. The proportions are measured by NMR.

[0099] In the polyamide (a), the total proportion of structural units derived from isophthalic acid and structural units derived from terephthalic acid in 100 mol% of structural units derived from dicarboxylic acids is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, particularly preferably 90 mol% or more, 95 mol% or more, or 98 mol% or more. The polyamide (a) may optionally contain structural units derived from dicarboxylic acids other than isophthalic acid and terephthalic acid (e.g., adipic acid).

[0100] The polyamide (a) preferably contains a structural unit derived from hexamethylenediamine as a diamine component. In the polyamide (a), the proportion of the structural units derived from hexamethylenediamine in 100 mol% of the structural units derived from diamine is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, particularly preferably 90 mol% or more, 95 mol% or more, or 98 mol% or more. The polyamide (a) may contain a structural unit derived from a diamine other than hexamethylenediamine, as necessary. The polyamide (a) is preferably PA6I / 6T.

[0101] The glass transition temperature (Tg) of the amorphous semi-aromatic polyamide is preferably 90°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, and preferably 180°C or lower, more preferably 160°C or lower, even more preferably 150°C or lower, for example, 90°C or higher and 180°C or lower. Amorphous semi-aromatic polyamides having a Tg equal to or higher than the above lower limit have excellent heat resistance. Therefore, by using such amorphous semi-aromatic polyamides, a surface resin layer with high heat resistance can be formed.

[0102] The melt volume rate (MVR) of the semi-aromatic polyamide is preferably 5 cm 3 / 10 minutes or more, preferably 10cm 3 / 10 minutes or more, preferably 200cm 3 / 10 minutes or less, preferably 100cm 3 / 10 minutes or less, for example, 5cm 3 / 200cm for more than 10 minutes 3 / 10 minutes or less. MVR is measured in accordance with JIS K7210-1:2014 at a temperature of 275°C and a load of 5.00 kg.

[0103] The relative viscosity of the polyamide is preferably 1.5 or more, more preferably 2.0 or more, even more preferably 2.5 or more, and preferably 5.0 or less, more preferably 4.5 or less, even more preferably 4.0 or less, for example, 1.5 or more and 5.0 or less. The relative viscosity of the polyamide is measured at 25°C in accordance with JIS K6920-2:2009 by dissolving 1 g of polyamide in 100 mL of 96% concentrated sulfuric acid.

[0104] From the viewpoint of film-forming ability and processability, the MFR of the polyamide is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, even more preferably 0.5 g / 10 min or more, and preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less, for example, 0.1 g / 10 min or more and 30 g / 10 min or less. The MFR of the polyamide is measured by Method A in accordance with JIS K7210-1:2014 under conditions of a temperature of 235°C and a load of 2.16 kg. An appropriate measurement temperature can be adopted depending on the melting point of the polyamide.

[0105] The surface resin layer (G) may contain polyamide as a main component. The surface resin layer (G) may contain an aliphatic polyamide as a main component. Such a stretched film has excellent processability and production costs. For example, the content of the aliphatic polyamide in the surface resin layer (G) may be 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more.

[0106] The surface resin layer (G) may contain aromatic polyamide as a main component. Such a stretched film has, for example, excellent rigidity and gas barrier properties. For example, the content of aromatic polyamide in the surface resin layer (G) may be 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more.

[0107] The surface resin layer (G) may contain an aliphatic polyamide and an aromatic polyamide. Aliphatic polyamides tend to have better processability. Aromatic polyamides tend to have better gas barrier properties and rigidity. For example, in the surface resin layer (G), from the viewpoint of balancing the rigidity, gas barrier properties, processability, and production costs of the stretched film, the content of the aliphatic polyamide may be 10% by mass or more and 90% by mass or less, 20% by mass or more and 80% by mass or less, 30% by mass or more and 70% by mass or less, or 40% by mass or more and 60% by mass or less, and the content of the aromatic polyamide may be 10% by mass or more and 90% by mass or less, 20% by mass or more and 80% by mass or less, 30% by mass or more and 70% by mass or less, or 40% by mass or more and 60% by mass or less.

[0108] The surface resin layer (G) may contain, as a main component, an amorphous semi-aromatic polyamide having a high glass transition temperature (e.g., 90°C or higher). Such a stretched film has, for example, excellent heat resistance. For example, the content of the amorphous semi-aromatic polyamide in the surface resin layer (G) may be 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more.

[0109] The surface resin layer (G) may contain a crystalline semi-aromatic polyamide and an amorphous semi-aromatic polyamide from the viewpoint of a balance between heat resistance and processability, etc. For example, in the surface resin layer (G), the content of the crystalline semi-aromatic polyamide may be 10% by mass or more and 90% by mass or less, 20% by mass or more and 80% by mass or less, 30% by mass or more and 70% by mass or less, or 40% by mass or more and 60% by mass or less, and the content of the amorphous semi-aromatic polyamide may be 10% by mass or more and 90% by mass or less, 20% by mass or more and 80% by mass or less, 30% by mass or more and 70% by mass or less, or 40% by mass or more and 60% by mass or less.

[0110] From the viewpoint of the above-mentioned physical properties such as gas barrier properties, the content of the gas barrier resin in the surface resin layer (G) is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more or 95% by mass or more.

[0111] The surface resin layer (G) may contain the above-mentioned resin materials other than the above-mentioned components. The surface resin layer (G) may contain the above-mentioned additives.

[0112] The thickness of the surface resin layer (G) in the stretched film is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 1.5 μm or more, from the viewpoint of the above-mentioned physical properties such as gas barrier properties. The thickness of the surface resin layer (G) is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less, from the viewpoint of recyclability. The thickness of the surface resin layer (G) is, for example, 0.5 μm or more and 10 μm or less.

[0113] The thickness of the surface resin layer (G) is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, and preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, for example, 1% or more and 30% or less, relative to the thickness of the stretched film.

[0114] ≪Surface resin layer (AH)≫ The surface resin layer (AH) contains polyethylene and an adhesive resin. The vapor-deposited film provided on the surface of the surface resin layer (AH) tends to have excellent adhesion to the surface resin layer (AH) and exhibit good gas barrier properties, for example.

[0115] Preferred polyethylenes include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. From the viewpoints of the surface smoothness of the stretched film and the adhesion between the surface resin layer (AH) and the vapor-deposited film, linear low-density polyethylene is more preferred. Examples of linear low-density polyethylene include C4-LLDPE, C6-LLDPE, and C8-LLDPE. For example, linear low-density polyethylene produced using a metallocene catalyst is preferred.

[0116] The melting point (Tm) of the polyethylene contained in the surface resin layer (AH) is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, and particularly preferably 115°C or higher, and is preferably 140°C or lower, for example, 100°C or higher and 140°C or lower, from the viewpoints of the strength and heat resistance of the stretched film and the adhesion between the surface resin layer (AH) and the vapor-deposited film.

[0117] Examples of adhesive resins include acid-modified resins, silicone resins, epoxy resins, and phenolic resins, with acid-modified resins being preferred. Examples of acid-modified resins include acid-modified polyolefins and acid-modified vinyl resins. Among these, from the viewpoints of recyclability and adhesion, acid-modified polyolefins are preferred, acid-modified polyethylene and acid-modified polypropylene are more preferred, acid-modified polyethylene is even more preferred, and acid-modified linear low-density polyethylene is even more preferred. A surface resin layer (AH) containing acid-modified linear low-density polyethylene tends to have better adhesion to a vapor-deposited film.

[0118] Examples of acid-modified polyolefins include polyolefins (e.g., polyethylene and polypropylene) modified with an acid-modifying component, particularly graft-modified polyolefins with an acid-modifying component. Examples of acid-modified components include unsaturated carboxylic acids such as maleic acid, fumaric acid, acrylic acid, methacrylic acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, and methyltetrahydrophthalic acid, or their acid anhydrides, esters, or metal salts. Preferred acid-modified polyolefins are maleic acid-modified polyolefins and maleic anhydride-modified polyolefins, with maleic acid-modified polyethylene, maleic anhydride-modified polyethylene, maleic acid-modified polypropylene, and maleic anhydride-modified polypropylene being more preferred, and maleic acid-modified polyethylene and maleic anhydride-modified polyethylene being even more preferred.

[0119] The content of the structural units derived from the acid-modified component in the acid-modified polyolefin is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of adhesion between the surface resin layer (AH) and the vapor-deposited film. The content of the structural units derived from the acid-modified component in the acid-modified polyolefin is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of adhesion between the surface resin layer (AH) and the polyethylene layer. The content is, for example, 0.01% by mass or more and 10% by mass or less. The content of the structural units derived from the acid-modified component is measured by infrared spectroscopy.

[0120] From the viewpoint of film-forming ability and processability, the MFR of the acid-modified polyolefin is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, even more preferably 0.5 g / 10 min or more, and preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less, for example, 0.1 g / 10 min or more and 30 g / 10 min or less. The MFR of the acid-modified polyolefin is measured by Method A under a load of 2.16 kg in accordance with JIS K7210-1:2014. The MFR measurement temperature is set depending on the melting point of the acid-modified polyolefin, and is 190°C for acid-modified polyethylene and 230°C for acid-modified polypropylene.

[0121] The density of the acid-modified polyethylene may be in the same range as that of the polyethylene described above. The melting point (Tm) of the acid-modified polyethylene is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, and particularly preferably 115°C or higher, and is preferably 140°C or lower, for example, 100°C or higher and 140°C or lower, from the viewpoints of the strength and heat resistance of the stretched film and the adhesion between the surface resin layer (AH) and the vapor-deposited film.

[0122] In the surface resin layer (AH), the polyethylene content is preferably 60% to 95% by mass and the adhesive resin content is preferably 5% to 40% by mass. It is more preferably 70% to 95% by mass and the adhesive resin content is 5% to 30% by mass. It is even more preferably 80% to 95% by mass and the adhesive resin content is 5% to 20% by mass. It is particularly preferably 85% to 95% by mass and the adhesive resin content is 5% to 15% by mass. The surface resin layer (AH) of this embodiment tends to have better surface smoothness, adhesion to the vapor-deposited film, and adhesion to the polyethylene layer. When the adhesive resin content is below the upper limit, for example, excessive adhesion of the film to a roll or the like can be suppressed during the production of a stretched film.

[0123] The surface resin layer (AH) may contain the above-mentioned resin materials other than the above-mentioned components. The surface resin layer (AH) may contain the above-mentioned additives.

[0124] The thickness of the surface resin layer (AH) in the stretched film is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 1.5 μm or more, from the viewpoint of further exerting the above-mentioned effects. The thickness of the surface resin layer (AH) is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less, from the viewpoint of recyclability. The thickness of the surface resin layer (AH) is, for example, 0.5 μm or more and 10 μm or less.

[0125] The thickness of the surface resin layer (AH) is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, and preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, for example, 1% or more and 30% or less, relative to the thickness of the stretched film.

[0126] ≪Adhesive resin layer≫ The stretched film of the first aspect may further comprise an adhesive resin layer between the polyethylene layer and the surface resin layer (G), and such a stretched film will have, for example, excellent interlayer adhesion.

[0127] The adhesive resin layer contains an adhesive resin as a main component. Examples of adhesive resins include acid-modified resins, silicone resins, epoxy resins, and phenolic resins, with acid-modified resins being preferred. Examples of acid-modified resins include acid-modified polyolefins and acid-modified vinyl resins. Among these, from the viewpoints of recyclability and adhesion to both the polyethylene layer and the surface resin layer, acid-modified polyolefins are preferred, acid-modified polyethylene and acid-modified polypropylene are more preferred, acid-modified polyethylene is even more preferred, and acid-modified linear low-density polyethylene is particularly preferred. Details of acid-modified polyolefins (composition, physical properties such as MFR, density, and Tm) are as explained in the section on the surface resin layer (AH), and will not be explained here.

[0128] From the viewpoint of adhesion between the polyethylene layer and the surface resin layer (G), the content of the structural units derived from the acid-modified component in the acid-modified polyolefin is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, for example, 0.01% by mass or more and 10% by mass or less. The content of the structural units derived from the acid-modified component is measured by infrared spectroscopy.

[0129] The adhesive resin content in the adhesive resin layer is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0130] The adhesive resin layer may contain the above-mentioned additives.

[0131] From the viewpoint of the above-mentioned adhesion, the thickness of the adhesive resin layer in the stretched film is preferably 0.5 μm or more, more preferably 0.8 μm or more, and even more preferably 1 μm or more. From the viewpoint of the recyclability of the stretched film and the barrier film, the thickness of the adhesive resin layer is preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. The thickness of the adhesive resin layer is, for example, 0.5 μm or more and 15 μm or less.

[0132] The thickness of the adhesive resin layer is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, and preferably 20% or less, more preferably 18% or less, even more preferably 15% or less, for example, 2% or more and 20% or less, relative to the thickness of the stretched film.

[0133] <Vapor deposition film> The barrier film of the present disclosure includes a first vapor-deposited film and a second vapor-deposited film, and has excellent gas barrier properties. Packaging containers made using such a barrier film also have excellent gas barrier properties. Because the barrier film includes the second vapor-deposited film on the first vapor-deposited film, deterioration of the gas barrier properties due to pinholes can be suppressed.

[0134] The surface resin layer (G) or (AH) of the stretched film has excellent vapor-deposited film formability, smoothness, and adhesion to the vapor-deposited film. The barrier film of the present disclosure has a vapor-deposited film on the surface resin layer (G) or (AH) of the stretched film. Such a barrier film has excellent gas barrier properties, specifically oxygen barrier properties and water vapor barrier properties, and, when the vapor-deposited film is a metal vapor-deposited film, has excellent brightness.

[0135] The barrier film comprises a first vapor-deposited film and a second vapor-deposited film in this order on the surface resin layer (G) or (AH) of the stretched film. Such a barrier film has, for example, superior gas barrier properties. The barrier film comprises a polyethylene layer, the surface resin layer (G) or (AH), the first vapor-deposited film, and the second vapor-deposited film in this order in the stacking direction. In one embodiment, the first vapor-deposited film is in contact with the surface resin layer (G) or (AH) of the stretched film. The barrier film may further comprise one or more vapor-deposited films on the second vapor-deposited film.

[0136] In one embodiment, the barrier film comprises, in this order, at least one polyethylene layer, an adhesive resin layer, a surface resin layer (G), a first vapor-deposited film, and a second vapor-deposited film. The barrier film of the above embodiment comprises, for example, a first polyethylene layer as the first surface resin layer, a second polyethylene layer, a third polyethylene layer, an adhesive resin layer, a surface resin layer (G) as the second surface resin layer, the first vapor-deposited film, and the second vapor-deposited film, in this order.

[0137] In one embodiment, the barrier film comprises, in this order, at least one polyethylene layer, a surface resin layer (AH), a first vapor-deposited film, and a second vapor-deposited film. The barrier film of the above embodiment comprises, for example, a first polyethylene layer as the first surface resin layer, a second polyethylene layer, a third polyethylene layer, a fourth polyethylene layer, a surface resin layer (AH) as the second surface resin layer, the first vapor-deposited film, and a second vapor-deposited film, in this order.

[0138] The first and second vapor-deposited films may be vapor-deposited films that constitute a multi-stage vapor-deposited film. An adhesion-improving layer, such as a barrier coat layer or a metal oxide film, described below, may be provided between the first and second vapor-deposited films to improve adhesion between them. The thickness and / or composition of the first and second vapor-deposited films may be the same or different.

[0139] In one embodiment, the vapor-deposited film is provided on the second surface of the stretched film, but not on the first surface of the stretched film. In one embodiment, the vapor-deposited film is provided on the second surface resin layer of the stretched film (surface resin layer (G) or (AH)), but not on the first surface resin layer of the stretched film. In the case of a barrier film having vapor-deposited films on both surfaces of a stretched film, when the barrier film is stored, for example, in a rolled form, the vapor-deposited films may deteriorate due to contact or rubbing against each other. The barrier film of the above embodiment can prevent such deterioration of the vapor-deposited film.

[0140] The vapor-deposited film may be composed of, for example, a metal and / or an inorganic oxide. The vapor-deposited film may be a metal vapor-deposited film composed of one or more metals, or an inorganic oxide vapor-deposited film composed of one or more inorganic oxides. The inorganic oxide vapor-deposited film may be a transparent vapor-deposited film. Examples of metals include aluminum, chromium, tin, nickel, copper, silver, gold, and platinum. Examples of inorganic oxides include aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide, and silicon carbide oxide (carbon-containing silicon oxide). Among vapor-deposited films, aluminum vapor-deposited films, aluminum oxide (alumina) vapor-deposited films, silicon oxide (silica) vapor-deposited films, and silicon carbide vapor-deposited films are preferred. The first and second vapor-deposited films are preferably aluminum vapor-deposited films, aluminum oxide (alumina) vapor-deposited films, silicon oxide (silica) vapor-deposited films, or silicon carbide vapor-deposited films, independently of one another.

[0141] From the viewpoint of gas barrier properties, the thicknesses of the first and second vapor-deposited films are each independently preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. From the viewpoint of suppressing cracking in the vapor-deposited films and improving the recyclability of packaging containers, the thicknesses of the first and second vapor-deposited films are each independently preferably 150 nm or less, more preferably 100 nm or less, and even more preferably 80 nm or less. The thickness is, for example, 1 nm or more and 150 nm or less.

[0142] The combination of the first and second vapor-deposited films is not particularly limited. From the viewpoint of gas barrier properties, the first vapor-deposited film may be a metal vapor-deposited film and the second vapor-deposited film may be a metal vapor-deposited film, and both may be the same or different. The first vapor-deposited film may be an aluminum vapor-deposited film and the second vapor-deposited film may be an aluminum vapor-deposited film, and both may be the same or different aluminum vapor-deposited films.

[0143] One of the first and second vapor-deposited films may be a metal vapor-deposited film and the other may be an inorganic oxide vapor-deposited film, or one of the first and second vapor-deposited films may be an aluminum vapor-deposited film and the other may be an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon carbide oxide vapor-deposited film. For example, the first vapor-deposited film may be an inorganic oxide vapor-deposited film and the second vapor-deposited film may be a metal vapor-deposited film, or the first vapor-deposited film may be a transparent vapor-deposited film such as an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon carbide oxide vapor-deposited film and the second vapor-deposited film may be an aluminum vapor-deposited film. In this case, the thickness of the aluminum vapor-deposited film can be measured in real time by measuring the amount of light transmittance during the formation of the second vapor-deposited film (during aluminum vapor deposition), making it easy to control the film thickness.

[0144] The first vapor-deposited film may be an inorganic oxide vapor-deposited film, and the second vapor-deposited film may be an inorganic oxide vapor-deposited film, both of which may be the same or different. The first vapor-deposited film may be an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon carbide oxide vapor-deposited film, and the second vapor-deposited film may be an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon carbide oxide vapor-deposited film, both of which may be the same or different. Such a barrier film has excellent transparency. Therefore, by using this barrier film, it is possible to produce, for example, packaging containers with excellent visibility of the contents, packaging containers that can be used in microwave ovens, and packaging containers that can pass through metal detectors. For example, by using this barrier film, it is possible to produce packaging containers that do not contain an aluminum vapor-deposited film. Consumers can clearly see that such packaging containers do not contain an aluminum vapor-deposited film. Therefore, such packaging containers are easy to separate and, further, the inclusion of black spots (metallic color) that can occur due to the aluminum vapor-deposited film during recycling can be suppressed.

[0145] For example, a packaging container is produced using a laminate including a barrier film with a metal vapor-deposited film such as an aluminum vapor-deposited film on both sides of a stretched film. Depending on the type of contents filled in the packaging container, the metal vapor-deposited film may be oxidized to form a metal oxide, causing discoloration or corrosion of the vapor-deposited film, or the vapor-deposited film may expand in volume, reducing the laminate strength and causing problems such as lifting or peeling of the layers.

[0146] In one embodiment, the barrier film of the present disclosure has a vapor-deposited film only on the second surface (second surface resin layer, surface resin layer (G) or (AH)) of the stretched film, and does not have a vapor-deposited film on the first surface (first surface resin layer) of the stretched film. By using a laminate including such a barrier film, a packaging container with excellent resistance to contents can be produced. For example, a laminate including a barrier film and a heat-seal layer is prepared. The laminate includes a barrier film arranged so that the stretched film faces the heat-seal layer (the inside of the packaging container) and the vapor-deposited film faces the outside (the outside of the packaging container). By producing a packaging container using the above laminate, the vapor-deposited film can be positioned on the outside. Therefore, even when corrosive contents are filled into the packaging container, discoloration, corrosion, or deterioration of the vapor-deposited film, as well as lifting and peeling of the layers, can be suppressed. For example, a laminate including a first heat-seal layer, a barrier film, and a second heat-seal layer is prepared. The laminate includes a barrier film arranged so that the stretched film faces the first heat-seal layer (the inside of the tube container) and the vapor-deposited film faces the second heat-seal layer (the outside of the tube container). By producing a tube container body using the laminate, the vapor-deposited film can be positioned on the outside. Therefore, even when a corrosive content is filled into the tube container, discoloration, corrosion, or deterioration of the vapor-deposited film, as well as lifting or peeling of the layers, can be suppressed.

[0147] When the vapor-deposited film is an aluminum vapor-deposited film, the optical density (OD value) of the aluminum vapor-deposited film is preferably 2.0 or more and 3.5 or less. Such an aluminum vapor-deposited film can, for example, improve the oxygen barrier property and water vapor barrier property while maintaining the productivity of the barrier film. The OD value is measured in accordance with JIS K7361-1:1997.

[0148] The surface of the vapor-deposited film may be subjected to the above-mentioned surface treatment, which may provide, for example, excellent adhesion to adjacent layers.

[0149] Examples of methods for forming vapor-deposited films include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0150] The vacuum level in the deposition chamber was 10 -2 ~10 -8 After oxygen is introduced, the pressure is preferably about 10 -1 ~10 -6 A pressure of about mbar is preferable. The amount of oxygen introduced varies depending on the size of the deposition machine. The oxygen introduced may be mixed with an inert gas such as argon gas, helium gas, or nitrogen gas as a carrier gas, provided that this does not cause any problems. The transport speed of the target film on which the deposition film is formed is, for example, 10 m / min to 800 m / min.

[0151] <Adhesion improving layer, protective layer> The barrier film of the present disclosure may further include an adhesion-improving layer, such as a barrier coat layer, between the first and second vapor-deposited films. The adhesion-improving layer is a layer that improves interlayer adhesion between the first and second vapor-deposited films. When the vapor-deposited film is composed of an inorganic oxide such as aluminum oxide or silicon oxide, such a barrier film can effectively suppress the occurrence of cracks in the vapor-deposited film and the deterioration of gas barrier properties. From the viewpoint of improving gas barrier properties, the adhesion-improving layer is preferably a barrier coat layer. The barrier film of the present disclosure may further include a protective layer, such as a barrier coat layer, on the surface of the second vapor-deposited film opposite to the surface facing the first vapor-deposited film. Such a barrier film has excellent scratch resistance and gas barrier properties, and when the vapor-deposited film is composed of an inorganic oxide such as aluminum oxide or silicon oxide, it can effectively prevent cracks from occurring in the vapor-deposited film and prevent a decrease in gas barrier properties. From the viewpoint of improving gas barrier properties, the protective layer is preferably a barrier coat layer.

[0152] When the first and second vapor-deposited films are metal vapor-deposited films, a metal oxide film may be formed between the first and second vapor-deposited films as an adhesion-improving layer. Forming a metal oxide film can improve the adhesion between the vapor-deposited films. Furthermore, forming a multilayer film including the first vapor-deposited film, a metal oxide film, and a second vapor-deposited film can stably form vapor-deposited films, rather than forming a single thick metal vapor-deposited film, in terms of high thickness uniformity, fewer defects, and so on.

[0153] The thickness of the metal oxide film as the adhesion improving layer is preferably 1 nm or more and 30 nm or less, more preferably 3 nm or more and 15 nm or less, from the viewpoint of the adhesion and gas barrier properties of the metal vapor deposition film.

[0154] The metal oxide film may be formed, for example, by forming a first vapor-deposited film and then introducing oxygen into metal vapor to vaporize the metal oxide obtained, or by heating the first vapor-deposited film in an oxygen atmosphere to oxidize the surface of the first vapor-deposited film. By forming a second vapor-deposited film on the surface of the metal oxide film, a barrier film can be produced that includes a metal vapor-deposited film as the first vapor-deposited film, a metal oxide film, and a metal vapor-deposited film as the second vapor-deposited film. It is preferable that the first vapor-deposited film is an aluminum vapor-deposited film, the metal oxide film is an aluminum oxide film, and the second vapor-deposited film is an aluminum vapor-deposited film. For example, after forming a first vapor-deposited film by aluminum vapor deposition, a small amount of oxygen is introduced into the aluminum vapor to form an aluminum oxide film on the first vapor-deposited film, and then the introduction of oxygen is stopped and a second vapor-deposited film is formed on the aluminum oxide film by vapor deposition of aluminum.

[0155] In one embodiment, the barrier film comprises, in this order, a polyethylene layer, a surface resin layer (G) or (AH), a metal vapor-deposited film as a first vapor-deposited film, an adhesion-improving layer such as a barrier coat layer or a metal oxide film, and a metal vapor-deposited film as a second vapor-deposited film. The metal vapor-deposited film is preferably an aluminum vapor-deposited film, and the metal oxide film is preferably an aluminum oxide film. In one embodiment, the barrier film comprises, in this order, a polyethylene layer, a surface resin layer (G) or (AH), a metal vapor-deposited film as a first vapor-deposited film, an adhesion-improving layer such as a first barrier coat layer, an inorganic oxide vapor-deposited film as a second vapor-deposited film, and a protective layer such as a second barrier coat layer. The metal vapor-deposited film is preferably an aluminum vapor-deposited film, and the inorganic oxide vapor-deposited film is preferably an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon oxide carbide vapor-deposited film. In one embodiment, the barrier film comprises, in this order, a polyethylene layer, a surface resin layer (G) or (AH), an inorganic oxide vapor-deposited film as a first vapor-deposited film, an adhesion-improving layer such as a barrier coat layer, and a metal vapor-deposited film as a second vapor-deposited film. The inorganic oxide vapor-deposited film is preferably an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon oxide carbide vapor-deposited film, and the metal vapor-deposited film is preferably an aluminum vapor-deposited film. In one embodiment, the barrier film comprises, in this order, a polyethylene layer, a surface resin layer (G) or (AH), an inorganic oxide vapor-deposited film as a first vapor-deposited film, an adhesion-improving layer such as a first barrier coat layer, an inorganic oxide vapor-deposited film as a second vapor-deposited film, and a protective layer such as a second barrier coat layer. The inorganic oxide vapor-deposited film is preferably an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon oxide carbide vapor-deposited film.

[0156] The thickness and / or composition of each deposited film may be the same as or different from one another. The thickness and / or composition of each adhesion improving layer, protective layer, and barrier coat layer may be the same as or different from one another.

[0157] In one embodiment, the adhesion improving layer, the protective layer, or the barrier coat layer contains a gas barrier resin. A barrier film including such a layer has even better gas barrier properties. The adhesion improving layer, the protective layer, or the barrier coat layer can be formed, for example, by applying a coating liquid obtained by dissolving or dispersing a material such as a gas barrier resin in water or an appropriate organic solvent to a vapor-deposited film and drying the resulting coating liquid.

[0158] Examples of gas barrier resins include ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyamides, polyvinylidene chloride, polyesters, polyether polyols, polyester polyols, polyurethanes, polyacrylonitrile, and (meth)acrylic resins.

[0159] In one embodiment, the content of the gas barrier resin in the adhesion improving layer, protective layer, or barrier coat layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more. Such a layer has, for example, excellent gas barrier properties.

[0160] The adhesion improving layer, the protective layer or the barrier coat layer may contain the above-mentioned additives.

[0161] The thickness of the adhesion improving layer, protective layer, or barrier coat layer containing a gas barrier resin is preferably 0.01 μm or more, more preferably 0.1 μm or more, from the viewpoint of gas barrier properties. The thickness of the adhesion improving layer, protective layer, or barrier coat layer containing a gas barrier resin is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of processability of the barrier film and recyclability of the packaging container. The thickness is, for example, 0.01 μm or more and 10 μm or less.

[0162] In another embodiment, the adhesion improving layer, protective layer, or barrier coat layer is a gas barrier coating film formed by applying a gas barrier composition to a vapor-deposited film and drying it. The gas barrier composition is obtained by mixing a metal alkoxide, a water-soluble polymer, and optionally a silane coupling agent, and adding, optionally, water, optionally an organic solvent, and optionally a sol-gel catalyst. The gas barrier coating film contains a hydrolysis polycondensate obtained by hydrolyzing and polycondensing the metal alkoxide or the like by a sol-gel method. By providing such a layer on a vapor-deposited film, when the vapor-deposited film is composed of an inorganic oxide, the gas barrier properties can be improved and the occurrence of cracks in the vapor-deposited film can be effectively suppressed.

[0163] Examples of metal alkoxides include alkoxysilanes, specifically tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0164] Examples of water-soluble polymers include hydroxyl group-containing polymers such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers. These water-soluble polymers can also contribute to improving gas barrier properties, for example. Depending on the desired physical properties such as oxygen barrier properties, water vapor barrier properties, water resistance, and weather resistance, either polyvinyl alcohol or ethylene-vinyl alcohol copolymers may be used, or both may be used in combination. A gas barrier coating film obtained using polyvinyl alcohol and a gas barrier coating film obtained using ethylene-vinyl alcohol copolymer may be laminated. The amount of water-soluble polymer used is preferably 5 to 500 parts by mass per 100 parts by mass of the metal alkoxide.

[0165] As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used, and an organoalkoxysilane having an epoxy group is preferred, such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The amount of the silane coupling agent used is preferably 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the metal alkoxide.

[0166] The gas barrier composition may contain water in an amount of preferably 0.1 mol or more, more preferably 0.5 mol or more, per mol of metal alkoxide, and preferably 100 mol or less, more preferably 60 mol or less. By setting the water content at or above the lower limit, for example, the oxygen barrier property and water vapor barrier property of the barrier film can be improved. By setting the water content at or below the upper limit, for example, the hydrolysis reaction can be carried out quickly.

[0167] The gas barrier composition may contain an organic solvent, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol.

[0168] The sol-gel catalyst is preferably an acid or an amine compound.

[0169] Examples of methods for applying the gas barrier composition include roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brush coating, bar coating, and applicator coating.

[0170] Hereinafter, one embodiment of the method for forming a gas barrier coating film will be described. A gas barrier composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and, if necessary, a silane coupling agent. A polycondensation reaction gradually progresses within the composition. The composition is then coated onto the vapor-deposited film by a conventional method and dried. This drying process further promotes polycondensation of the metal alkoxide and the water-soluble polymer (and the silane coupling agent, if the composition contains one) to form a composite polymer layer. Multiple composite polymer layers may be laminated by repeating the above process. For example, the coated composition is heated at a temperature of preferably 20°C or higher, more preferably 50°C or higher, and even more preferably 70°C or higher, and preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower, for 1 second to 10 minutes. In this manner, a gas barrier coating film can be formed.

[0171] The thickness of the gas barrier coating film is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 5 μm or less, still more preferably 2 μm or less, and particularly preferably 1 μm or less, for example, 0.01 μm or more and 100 μm or less. A barrier film having such a gas barrier coating film has, for example, excellent gas barrier properties, can suppress the occurrence of cracks in a vapor-deposited film made of an inorganic oxide, and also provides excellent recyclability and processability of the packaging container.

[0172] <Print layer> The barrier film of the present disclosure may further include a printed layer, which will be described later. The printed layer may be provided, for example, on the surface of the second vapor-deposited film, on the surface of the protective layer, or on the surface of the first surface resin layer.

[0173] <Layer structure of barrier film> Hereinafter, several examples of the layer structure of the barrier film of the present disclosure will be given with reference to the drawings. The barrier film 1 shown in FIG. 1A comprises a polyethylene layer 10, a surface resin layer (G) or (AH) 20, a first vapor-deposited film 41, and a second vapor-deposited film 42 in this order. The barrier film 1 shown in FIG. 1B comprises, in this order, a first polyethylene layer 11, a second polyethylene layer 12, a third polyethylene layer 13, an adhesive resin layer 30, a surface resin layer (G) 20, a first vapor-deposited film 41, and a second vapor-deposited film 42. The barrier film 1 shown in FIG. 1C includes, in this order, a first polyethylene layer 11, a second polyethylene layer 12, a third polyethylene layer 13, a fourth polyethylene layer 14, a surface resin layer (AH) 20, a first vapor-deposited film 41, and a second vapor-deposited film 42. The barrier film 1 shown in FIG. 2 comprises, in this order, a polyethylene layer 10, a surface resin layer (G) or (AH) 20, a first vapor-deposited film 41, an adhesion-improving layer 50 such as a barrier coat layer or a metal oxide film, and a second vapor-deposited film 42. The barrier film 1 shown in FIG. 3 comprises, in this order, a polyethylene layer 10, a surface resin layer (G) or (AH) 20, a first vapor-deposited film 41, an adhesion-improving layer 51 such as a first barrier coat layer or a metal oxide film, a second vapor-deposited film 42, and a protective layer 52 such as a second barrier coat layer.

[0174] <Gas barrier properties of barrier film> The oxygen permeability (unit: cc / (m 2The oxygen permeability (°C / °F) may be, for example, less than 3.0, less than 1.5, less than 1.0, less than 0.6, less than 0.3, less than 0.2, or less than 0.1. The lower limit of the oxygen permeability may be, for example, 0.01. The oxygen permeability is measured in accordance with JIS K7126-2:2006 in an environment at a temperature of 23°C and a humidity of 90% RH.

[0175] The water vapor permeability (unit: g / (m 2 The water vapor permeability (day)) may be, for example, less than 3.0, less than 1.5, less than 1.0, less than 0.6, less than 0.3, less than 0.2, or less than 0.1. The lower limit of the water vapor permeability may be, for example, 0.01. The water vapor permeability is measured in accordance with JIS K7129-2:2019 in an environment at a temperature of 40°C and a humidity of 90% RH.

[0176] [Laminate] The laminate of the present disclosure comprises: A barrier film of the present disclosure; a heat seal layer; At least the following is provided. In one embodiment, the laminate of the present disclosure comprises at least a first heat seal layer; A barrier film of the present disclosure; a second heat seal layer; and are provided in this order.

[0177] The laminate of the present disclosure can be suitably used as a packaging material. The laminate of the present disclosure can be suitably used, for example, as a packaging material for forming the body of a tube container body. In this case, for example, the second heat seal layer is a sealant layer on the outer surface side of the body, and the first heat seal layer is a sealant layer on the inner surface side of the body. That is, the body comprises, from the outside to the inside of the body, the second heat seal layer, a barrier film, and a first heat seal layer, in this order.

[0178] In one embodiment, the laminate of the present disclosure does not include aluminum foil. In one embodiment, the laminate of the present disclosure does not include either a polyethylene terephthalate film or aluminum foil. Such a laminate and a packaging container including the laminate have excellent recyclability.

[0179] In one embodiment, the total thickness of the laminate of the present disclosure may be 40 μm or more, 60 μm or more, 80 μm or more, 100 μm or more, 120 μm or more, 140 μm or more, 400 μm or less, 350 μm or less, or 300 μm or less, for example, 40 μm or more and 400 μm or less. The total thickness of the laminate can be changed as appropriate depending on, for example, the use or shape of the packaging container.

[0180] <Base material> The laminate of the present disclosure includes the barrier film of the present disclosure. The laminate of the present disclosure may include two or more barrier films. Details of the barrier film are as described above, and detailed description will be omitted here.

[0181] In a laminate comprising a barrier film and a heat-sealing layer, the orientation of the barrier film is not particularly limited. From the viewpoint of resistance to contents, the barrier film may be arranged so that the polyethylene layer faces the heat-sealing layer (inside the packaging container) and the vapor-deposited film faces the opposite side to the heat-sealing layer (outside the packaging container). That is, the laminate may comprise, in this order, the heat-sealing layer, the polyethylene layer, the surface resin layer (G) or (AH), the first vapor-deposited film, and the second vapor-deposited film.

[0182] The laminate of the present disclosure may further include an oriented polyolefin substrate. The oriented polyolefin substrate is a polyolefin substrate that has been subjected to a stretching treatment. The oriented polyolefin substrate contains polyolefin as a main component. Examples of polyolefins include polyethylene, polypropylene, polybutene, and polymethylpentene. Among these, polyethylene and polypropylene are preferred, and polyethylene is more preferred. Examples of the oriented polyolefin substrate are preferred, such as an oriented polyethylene substrate containing polyethylene as a main component, and an oriented polypropylene substrate containing polypropylene as a main component, and polyethylene substrates are more preferred. The stretching treatment may be uniaxial or biaxial stretching. Details of the stretching treatment are as described above, and will not be described here. The oriented polyolefin substrate may be, for example, a uniaxial or biaxially stretched substrate.

[0183] The oriented polyethylene substrate contains polyethylene as a main component. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer. The oriented polyethylene substrate is not particularly limited, but in one embodiment, it is a uniaxially oriented polyethylene substrate, specifically a polyethylene substrate uniaxially oriented in the MD direction (MDO substrate).

[0184] The oriented polyolefin substrate may contain a biomass polyolefin. The oriented polyolefin substrate may contain recycled polyolefin. The oriented polyolefin substrate may contain the above-mentioned additives.

[0185] The polyolefin content in the oriented polyolefin substrate is preferably more than 50% by mass, more preferably 80% by mass or more, even more preferably 85% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0186] The oriented polyolefin substrate may have a single layer structure or a multilayer structure. The thickness of the oriented polyolefin substrate is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 10 μm or more, from the viewpoint of the strength and heat resistance of the laminate. The thickness of the oriented polyolefin substrate is preferably 300 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less, from the viewpoint of the processability of the laminate. The thickness of the oriented polyolefin substrate is, for example, 5 μm or more and 300 μm or less.

[0187] The oriented polyolefin substrate may be subjected to the above-mentioned surface treatment. Such an oriented polyolefin substrate has, for example, excellent adhesion to a layer adjacent to the substrate. An anchor coating layer may be formed on the surface of the oriented polyolefin substrate using a conventionally known anchor coating agent.

[0188] The laminate further comprising a oriented polyolefin substrate may, for example, comprise a heat seal layer, a barrier film of the present disclosure, and a oriented polyolefin substrate in this order, or may comprise a heat seal layer, a oriented polyolefin substrate, and a barrier film of the present disclosure in this order.

[0189] <Print layer> The laminate of the present disclosure may include a printed layer on one or both surfaces of the substrate, such as the barrier film and the oriented polyolefin substrate, described above. The laminate of the present disclosure may also include a printed layer on the second heat-sealable layer described below.

[0190] The print layer includes an image. Examples of the image include letters, figures, patterns, symbols, and combinations thereof. The image may include text information such as the product name, the name of the item in the packaging container, the manufacturer, and the names of ingredients. The image may be a single, solid color (a so-called solid image).

[0191] The printed layer can be formed, for example, using an ink composition. Methods for forming the printed layer include, for example, gravure printing, offset printing, flexographic printing, screen printing, letterpress printing, and transfer printing. From the viewpoint of reducing the environmental load, the printed layer may be formed by flexographic printing. From the viewpoint of reducing the environmental load, the printed layer may be formed using ink derived from biomass.

[0192] The thickness of the printed layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, for example, 0.1 μm or more and 10 μm or less.

[0193] <Surface protective layer> The laminate of the present disclosure may include a surface protective layer on the printed layer provided on the second heat seal layer described below in order to improve the scratch resistance and weather resistance of the printed layer. The laminate of the present disclosure preferably includes a surface protective layer that covers the entire area of ​​the printed layer. From the viewpoint of visibility of the printed layer, the surface protective layer is preferably transparent in the visible light range, and more preferably colorless and transparent.

[0194] The surface protective layer contains, for example, a cured product of a thermoplastic resin, a thermosetting resin, or a cured product of an energy ray-curable compound. Among these, from the viewpoint of improving scratch resistance and weather resistance, the surface protective layer preferably contains a cured product of a thermosetting resin or a cured product of an energy ray-curable compound, and more preferably contains a cured product of an energy ray-curable compound. The proportion of the cured product in the total resin components of the surface protective layer is preferably 80% by mass or more, more preferably 90% by mass or more. Methods for forming the surface protective layer include, for example, letterpress printing, flexographic printing, gravure printing, offset printing, screen printing, inkjet printing, and thermal transfer printing.

[0195] The thickness of the surface protective layer is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 15 μm or less, more preferably 10 μm or less, for example, 0.5 μm or more and 15 μm or less. A laminate including such a surface protective layer has, for example, excellent scratch resistance and weather resistance.

[0196] <Heat seal layer> The laminate of the present disclosure comprises a heat seal layer. The heat-seal layer contains, as its main component, a heat-fusible resin that can be melted and fused to each other by heat. Examples of heat-fusible resins include polyolefins such as polyethylene, polypropylene, and polymethylpentene, cyclic polyolefins, cyclic olefin copolymers, ionomer resins, acid-modified polyolefins, and ethylene-(meth)acrylic acid ester-unsaturated carboxylic acid terpolymers. Examples of polyethylene include linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, and ethylene-(meth)acrylic acid ester copolymers. Examples of acid-modified polyolefins include resins obtained by modifying polyolefins such as polyethylene and polypropylene with unsaturated carboxylic acid compounds such as (meth)acrylic acid and maleic anhydride. The heat-fusible resin may be a material derived from fossil fuels, a biomass-derived material such as biomass polyethylene, or a recycled material such as recycled polyethylene. Two or more of these may also be used.

[0197] In recent years, there has been a demand for recycling packaging containers from the viewpoint of reducing environmental impact. From the viewpoint of recyclability, it is preferable that the substrate and the heat seal layer are each made of the same type of resin material (mono-material). In one embodiment, the heat seal layer contains polyethylene as a main component. With this configuration, the packaging container can be made mono-material. Such packaging containers have excellent recyclability, and there is no need to separate the substrate and the heat seal layer, for example, after collecting used packaging containers. The above-mentioned laminate in which the heat seal layer contains polyethylene as a main component can be suitably used as a packaging material such as a polyethylene-based mono-material packaging material.

[0198] The polyethylene content in the entire laminate of the present disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. For example, a mono-material packaging container can be produced using such a laminate, thereby improving the recyclability of the packaging container. The upper limit of the polyethylene content is not particularly limited, but may be 99% by mass.

[0199] From the viewpoint of heat-sealability, the heat-seal layer preferably contains low-density polyethylene and / or linear low-density polyethylene. When the heat-seal layer contains low-density polyethylene and linear low-density polyethylene, the content (mass%) of the linear low-density polyethylene may be greater than the content (mass%) of the low-density polyethylene.

[0200] In one embodiment, the melting point (Tm) of the polyethylene contained in the heat seal layer is preferably 90°C or higher, more preferably 95°C or higher, and preferably 140°C or lower, more preferably 130°C or lower, for example, 90°C or higher and 140°C or lower, from the viewpoint of a balance between heat resistance and heat sealability.

[0201] In one embodiment, the content of polyethylene in the heat seal layer is preferably more than 50% by mass, more preferably 80% by mass or more, and even more preferably 90% by mass or more. A laminate including such a heat seal layer has excellent recyclability, for example.

[0202] The heat seal layer may contain the above-mentioned additives.

[0203] The laminate of the present disclosure may include at least a first heat-sealing layer as the heat-sealing layer, a barrier film of the present disclosure, and a second heat-sealing layer as the heat-sealing layer, in this order. The first heat-sealing layer and the second heat-sealing layer can be melted by heating and fused to each other. Such a laminate can be suitably used, for example, as a packaging material for forming the body of a tube container.

[0204] In one embodiment, the first and second heat-seal layers contain polyethylene as a main component, and the polyethylene contained in the first heat-seal layer and the polyethylene contained in the second heat-seal layer may be the same or different.

[0205] In the laminate of the above embodiment, the orientation of the barrier film is not particularly limited. From the viewpoint of resistance to contents, the barrier film may be arranged so that the polyethylene layer faces the first heat-seal layer and the vapor-deposited film faces the second heat-seal layer. That is, the laminate may include, in this order, the first heat-seal layer, the polyethylene layer, the surface resin layer (G) or (AH), the first vapor-deposited film, the second vapor-deposited film, and the second heat-seal layer.

[0206] The heat seal layer may have a single-layer structure or a multi-layer structure. The first and second heat seal layers may have a single-layer structure or a multi-layer structure.

[0207] The thickness of the heat seal layer may be 10 μm or more, 20 μm or more, 30 μm or more, 50 μm or more, 60 μm or more, 70 μm or more, or 80 μm or more from the viewpoint of heat sealing properties and recyclability of the packaging container. The thickness of the heat seal layer may be 300 μm or less, 200 μm or less, or 150 μm or less from the viewpoint of processability of the laminate. The thickness of the heat seal layer is, for example, 10 μm or more and 300 μm or less. The thicknesses of the first and second heat seal layers are also preferably independently within the above ranges. The thickness of the heat seal layer can be appropriately changed depending on, for example, the use or shape of the packaging container. In the case of a small bag, the thickness of the heat seal layer may be, for example, 20 μm or more and 60 μm or less, but is not particularly limited. In the case of a standing pouch, the thickness of the heat seal layer may be, for example, 60 μm or more and 150 μm or less, but is not particularly limited. In the case of a tube container, the thickness of each heat seal layer may be, for example, 50 μm or more, 60 μm or more, 70 μm or more, or 80 μm or more, but is not particularly limited.

[0208] From the viewpoint of heat sealing property, the heat seal layer is preferably an unstretched resin film, more preferably an unstretched co-extruded resin film, and each layer constituting the heat seal layer is a co-extruded resin layer. The above resin film can be produced, for example, by using a T-die casting method or an inflation method. The concept of "unstretched film" includes not only a film that is not stretched at all, but also a film that is slightly stretched due to the tension applied during film formation.

[0209] For example, an unstretched resin film corresponding to the heat seal layer may be laminated on the barrier film via an adhesive layer as needed, or the heat seal layer may be formed by melt-extruding a heat-fusible resin or a resin composition thereof onto the barrier film. In the latter case, an adhesive layer may not be provided. Examples of adhesive layers include the following adhesive layers.

[0210] <Adhesive layer> The laminate of the present disclosure may include an adhesive layer between any layers, such as between a substrate such as a barrier film and a heat seal layer. Such a laminate has excellent adhesion between the substrate and the heat seal layer, for example.

[0211] The laminate of the present disclosure may, for example, comprise a heat-sealing layer, an adhesive layer, and a barrier film of the present disclosure, in this order; a heat-sealing layer, a first adhesive layer, a barrier film of the present disclosure, a second adhesive layer, and an oriented polyolefin substrate, in this order; or a heat-sealing layer, a first adhesive layer, an oriented polyolefin substrate, a second adhesive layer, and a barrier film of the present disclosure, in this order. The laminate of the present disclosure may, for example, comprise a first heat-sealing layer, a first adhesive layer, a barrier film of the present disclosure, a second adhesive layer, and a second heat-sealing layer, in this order.

[0212] In one embodiment, the adhesive layer may be an adhesive layer made of an adhesive. The adhesive may be any of a one-component curing adhesive, a two-component curing adhesive, and a non-curing adhesive. The adhesive may be a solventless adhesive or a solvent-based adhesive. Among these, a solvent-based adhesive is preferred because it has better resistance to contents.

[0213] Examples of solvent-free adhesives, i.e., non-solvent laminate adhesives, include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Among these, urethane adhesives are preferred, and two-component curing urethane adhesives are more preferred.

[0214] Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, olefin-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and urethane-based adhesives. Among these, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are more preferred.

[0215] In one embodiment, the laminate of the present disclosure may be produced by laminating a barrier film, an optional stretched polyolefin substrate, and a resin film corresponding to the heat seal layer by a non-solvent lamination method using a solvent-free adhesive, or by a dry lamination method using a solvent-based adhesive. The adhesive layer can be formed by applying an adhesive to the barrier film or the like and drying it by a method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, or transfer roll coating.

[0216] The thickness of the adhesive layer may be 0.1 μm or more, 0.2 μm or more, 0.5 μm or more, 10 μm or less, 8 μm or less, or 6 μm or less, for example, 0.1 μm or more and 10 μm or less. The thickness of the adhesive layer may be 2 μm or less.

[0217] In one embodiment, the adhesive layer may be an adhesive resin layer containing a thermoplastic resin, or an extruded resin layer containing a thermoplastic resin. Examples of the thermoplastic resin include the above-mentioned heat-sealable resins. The thermoplastic resin may be a material derived from fossil fuels, a material derived from biomass, or a recycled material, or two or more of these may be used.

[0218] The thickness of the extruded resin layer is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of interlayer adhesion. The thickness of the extruded resin layer is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of reducing the production cost of the laminate and improving its productivity. The thickness of the extruded resin layer is, for example, 5 μm or more and 30 μm or less.

[0219] <Layer structure of laminate> Hereinafter, several examples of the layer configuration of the laminate of the present disclosure will be given with reference to the drawings. 4 includes a heat seal layer 80, an adhesive layer 60, and a barrier film 1 in this order, specifically, a heat seal layer 80, an adhesive layer 60, a polyethylene layer 10, a surface resin layer (G) or (AH) 20, a first vapor-deposited film 41, and a second vapor-deposited film 42 in this order. The laminate 2 may further include a printed layer (not shown). For example, the laminate 2 may further include a printed layer on the polyethylene layer 10 or the second vapor-deposited film 42 of the barrier film 1.

[0220] The laminate 2 shown in FIG. 5 comprises a heat seal layer 80, a first adhesive layer 61, a barrier film 1, a second adhesive layer 62, and an oriented polyolefin substrate 70, in this order. Specifically, the laminate 2 comprises a heat seal layer 80, a first adhesive layer 61, a polyethylene layer 10, a surface resin layer (G) or (AH) 20, a first vapor-deposited film 41, a second vapor-deposited film 42, the second adhesive layer 62, and an oriented polyolefin substrate 70, in this order. The laminate 2 may further comprise a printed layer (not shown). For example, the laminate 2 may further comprise a printed layer on the surface of the oriented polyolefin substrate 70 facing the second adhesive layer 62. A laminate having such a configuration is suitable as a packaging material for forming, for example, a stand-up pouch.

[0221] The laminate 2 shown in FIG. 6 includes, in this order, a first heat-seal layer 81, a first adhesive layer 61, a barrier film 1, a second adhesive layer 62, and a second heat-seal layer 82. Specifically, the laminate 2 includes, in this order, the first heat-seal layer 81, the first adhesive layer 61, a polyethylene layer 10, a surface resin layer (G) or (AH) 20, a first vapor-deposited film 41, a second vapor-deposited film 42, the second adhesive layer 62, and the second heat-seal layer 82. The laminate 2 may further include a printed layer (not shown). The laminate 2 may further include a printed layer, for example, on the surface of the second heat-seal layer 82. A laminate having such a configuration is suitable, for example, as a packaging material for forming the barrel of a tube container body.

[0222] 4 to 6, the barrier film 1 may further include a barrier coating layer (not shown) between the first vapor-deposited film 41 and the second vapor-deposited film 42 and / or on the second vapor-deposited film 42. In Figures 4 to 6, the orientation of the barrier film 1 may be reversed. In Figures 4 to 6, the adhesive layers 60, 61, 62 may be, for example, adhesive layers or extruded resin layers.

[0223] [Packaging container] The laminate of the present disclosure can be suitably used for packaging material applications. Packaging materials are used to produce packaging containers. By using at least the laminate of the present disclosure, packaging containers with excellent gas barrier properties can be produced.

[0224] Examples of packaging containers include packaging bags, tube containers, and containers with lids.

[0225] Examples of packaging bags include various types of packaging bags, such as stand-up pouch type, side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, grommed seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type.The packaging bag may be, for example, a small pouch or a zipper bag.The packaging bag may also be a refill pouch for storing contents such as liquids and powders to be refilled into containers such as bottles, and in particular may be a stand-up pouch.The packaging bag may also be, for example, a flexible packaging bag.

[0226] The packaging container of the present disclosure comprises the laminate of the present disclosure. The packaging container of the present disclosure may be, for example: one or more laminates of the present disclosure; a seal portion where the heat seal layers of the laminate are joined together; a storage section for storing contents; It has. The seal portion includes an inner edge that defines the receptacle portion.

[0227] Examples of methods for forming the sealed portion include heat sealing, in which the heat-sealed layers of the laminate are melted by heating or the like to fuse the heat-sealed layers together, and specific examples include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high-frequency sealing, and ultrasonic sealing. For example, after the contents are placed in the packaging bag, the opening of the packaging bag can be heat-sealed to seal the packaging bag.

[0228] The packaging bag may have an easy-to-open portion. Examples of the easy-to-open portion include a notch portion that serves as a starting point for tearing the packaging bag, and a half-cut line formed by laser processing or a cutter as a path for tearing the packaging bag.

[0229] In one embodiment, the laminate of the present disclosure is used as a lid material in a lidded container. The lidded container comprises a container body having a storage compartment and a lid material joined (heat sealed) to the container body so as to seal the storage compartment. Here, the lid material, i.e., the heat seal layer of the laminate, and the container body are heat sealed. Examples of the shape of the container body include a cup shape and a cylindrical shape with a bottom. The container body is made of, for example, polystyrene, polypropylene, polyethylene, or paper.

[0230] The contents housed in the packaging container include, for example, liquids, solids, powders, and gels. The contents may be food or beverages, or non-food or beverages such as chemicals, cosmetics, pharmaceuticals, metal parts, and electronic components. Examples of the contents include shampoo, rinse, conditioner, hand soap, body soap, air fresheners, deodorants, insect repellents, fabric softeners, detergents; sauces, soy sauce, dressings, cooking oils, mayonnaise, ketchup, syrups, cooking alcohol, and other liquid or viscous condiments; fruit juices; spices; liquid beverages, jelly-like beverages, liquid soups, powdered soups, instant foods, other food and beverages; creams; toothpaste; metal parts, and electronic components. For example, toothpaste is a preferred content for tube containers.

[0231] In one embodiment, a packaging bag can be produced by folding the laminate of the present disclosure in half and overlapping them so that the barrier film is on the outside and the heat seal layer is on the inside, and then heat-sealing the edges, etc. In another embodiment, a packaging bag can be produced by overlapping multiple laminates of the present disclosure so that the heat seal layers face each other and heat-sealing the edges, etc. The entire packaging bag may be composed of the above-mentioned laminate, or only a portion of the packaging bag may be composed of the above-mentioned laminate.

[0232] In one embodiment, the stand-up pouch comprises a body portion composed of side sheets and a bottom portion composed of a bottom sheet. The bottom sheet maintains the shape of the side sheets, thereby imparting self-supporting properties to the pouch and enabling it to be a stand-up pouch. A storage compartment for storing contents is formed within the area surrounded by the side sheets and the bottom sheet. In the stand-up pouch, only the side sheets may be the laminate of the present disclosure, only the bottom sheet may be the laminate of the present disclosure, or both the side sheets and the bottom sheet may be the laminate of the present disclosure.

[0233] In one embodiment, the side sheet can be formed by preparing two laminates of the present disclosure, overlapping them with their heat-sealable layers facing each other, and heat-sealing both side edges to form a bag.

[0234] In another embodiment, the side sheets can be formed by preparing two laminates of the present disclosure, overlapping them with their heat-sealable layers facing each other, inserting two V-folded laminates with their heat-sealable layers facing outward between the laminates at the side edges of both sides of the overlapped laminates, and heat-sealing the two laminates. This production method produces a stand-up pouch having a body with side gussets.

[0235] In one embodiment, the bottom sheet can be formed by inserting the laminate of the present disclosure between the lower portions of the side sheets of a bag and heat-sealing the laminate. More specifically, the bottom sheet can be formed by inserting the laminate folded in a V-shape with the heat-seal layer facing outward between the lower portions of the side sheets of a bag and heat-sealing the laminate.

[0236] In one embodiment, two laminates of the present disclosure are prepared and stacked together with their heat-sealable layers facing each other. Then, another laminate of the present disclosure is folded in a V-shape with its heat-sealable layer facing outward, and this is sandwiched between the two laminates and heat-sealed to form a bottom. Next, two sides adjacent to the bottom are heat-sealed to form a body. In this manner, a stand-up pouch according to one embodiment can be formed.

[0237] [Tube container body] The tube container body of the present disclosure includes the laminate of the present disclosure. The tube container body of the present disclosure will be described below with reference to the drawings. Fig. 7 is a diagram showing a simplified configuration of a tube container 120, and Fig. 8 is a cross-sectional view taken along line AA in Fig. 7. As shown in Fig. 7, the tube container body 121 includes a head 122 and a body 123, and the body 123 is made of the laminate of the present disclosure.

[0238] <Head> The head 122 includes a shoulder 124 connected to one end of the body 123, and a spout 125 connected to the shoulder 124. In one embodiment, the spout 125 includes threads 127 for threading a cap 126 onto the spout 125.

[0239] In one embodiment, the head portion is formed from a resin composition containing polyethylene. Such a head portion can improve the recyclability of the tube container body. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Among these, high-density polyethylene is preferred from the viewpoints of shape retention and moldability. The resin composition may contain at least one selected from the group consisting of biomass polyethylene and recycled polyethylene. The resin composition may also contain the additive.

[0240] The head portion can be produced by a conventionally known method, for example, by compression molding or injection molding, and can be joined to the body portion.

[0241] <Body> In the tube container body 121 of the present disclosure, the body 123 is connected to a shoulder 124 of the head 122. The body 123 includes a fused portion 128 formed, for example, by overlapping the laminate of the present disclosure at one end so that the surface of the first heat-sealed layer at the other end is in contact with the surface of the second heat-sealed layer at the other end, rolling the laminate into a cylindrical shape, and heat-sealing the overlapped portion. The body 123 includes a bottom seal portion 129 formed, for example, by heat-sealing the opening of the cylindrically rolled laminate.

[0242] Examples of heat sealing methods include conventionally known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, and flame sealing.

[0243] For example, a cylindrical body portion may be produced by overlapping one end of the laminate of the present disclosure so that the surface of the first heat-seal layer at one end is in contact with the surface of the second heat-seal layer at the other end, rolling the laminate into a cylindrical shape, and heat-sealing the overlapped portion. From the viewpoint of heat-sealability, it is preferable that one overlapping end is the first heat-seal layer and the other end is the second heat-seal layer. In this case, the first heat-seal layer and the second heat-seal layer are melted and joined to form a fused portion.

[0244] Therefore, it is preferable that the second heat-sealing layer does not have a printed layer or a surface protective layer formed in the area where heat sealing is to be performed when forming the body of the tube container body. With this configuration, when forming the cylindrical body using the laminate of the present disclosure, the area can be heat-sealed well.

[0245] In the above embodiment, the fused portion is formed by overlapping, but it may also be possible to butt the same surfaces of both ends of the laminate together and heat-seal the first heat-seal layers to join them. In this case, a printed layer and a surface protective layer may be formed on the second heat-seal layer at both ends of the laminate. Also, in this case, a bonding tape may be applied to the outer surface of the body portion so as to cover the bonding portion. It is preferable that a printed layer and a surface protective layer are not provided at the location of the laminate where the bonding tape is applied. The bonding tape may be provided on both the inner and outer surfaces of the body portion.

[0246] [Tube container] The tube container of the present disclosure will be described below with reference to the drawings. As shown in Fig. 7, the tube container 120 of the present disclosure includes a tube container body 121 and a cap 26 attached to a head portion 122.

[0247] <Tube container body> The tube container body has been described above, so a description thereof will be omitted here.

[0248] <Cap> The cap is removably attached to the spout of the head. The cap serves to close the spout. In one embodiment, the cap is formed from a resin composition containing a thermoplastic resin. Examples of thermoplastic resins include polyolefins such as polyethylene and polypropylene, polyesters, cellulose resins, and vinyl resins. From the viewpoint of recyclability, polyethylene is particularly preferred. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Among these, high-density polyethylene is preferred from the viewpoint of shape retention and ease of opening. The resin composition may contain at least one selected from the group consisting of biomass polyethylene and recycled polyethylene. The resin composition may also contain the additives described above.

[0249] The cap may be a screw type having a groove on the inner surface of the cap so as to screw onto the thread 127 of the extraction port 125, as shown in FIG. 7, or it may be a stopper type that fits onto the extraction port 125 by tapping it.

[0250] [Example of implementation] The present disclosure relates to, for example, the following [1] to

[18] . [1] A barrier film comprising at least a stretched film, a first vapor-deposited film, and a second vapor-deposited film in this order in the lamination direction, the stretched film comprising at least a polyethylene layer containing polyethylene as a main component, and a surface resin layer containing a gas barrier resin as a main component or containing polyethylene and an adhesive resin, and the first vapor-deposited film is provided on the surface resin layer. [2] The barrier film according to [1] above, wherein the first vapor-deposited film and the second vapor-deposited film are each independently a metal vapor-deposited film. [3] The barrier film according to [1] above, wherein the first vapor-deposited film is an inorganic oxide vapor-deposited film, and the second vapor-deposited film is a metal vapor-deposited film. [4] The barrier film according to [1] above, wherein the first vapor-deposited film and the second vapor-deposited film are each independently an inorganic oxide vapor-deposited film. [5] The barrier film according to any one of [1] to [4], further comprising an adhesion-improving layer between the first vapor-deposited film and the second vapor-deposited film. [6] The barrier film according to [5] above, wherein the adhesion improving layer is a barrier coat layer or a metal oxide film. [7] The barrier film according to any one of [1] to [6], further comprising a protective layer on the surface of the second vapor-deposited film opposite to the surface facing the first vapor-deposited film. [8] The barrier film according to [7], wherein the protective layer is a barrier coat layer. [9] The barrier film according to any one of [1] to [8], wherein the stretched film has a first surface and a second surface opposite to the first surface, the first vapor-deposited film is provided on the second surface of the stretched film, and the barrier film does not have a vapor-deposited film on the first surface of the stretched film.

[10] The barrier film according to any one of [1] to [9], wherein the surface resin layer is a layer containing a gas barrier resin as a main component, and the surface resin layer contains, as the gas barrier resin, at least one selected from the group consisting of an ethylene-vinyl alcohol copolymer, a polyvinyl alcohol, and a polyamide.

[11] The barrier film according to any one of [1] to [9], wherein the surface resin layer is a layer containing polyethylene and an adhesive resin, the content of the polyethylene in the surface resin layer being 60% by mass or more and 95% by mass or less, and the content of the adhesive resin being 5% by mass or more and 40% by mass or less.

[12] The barrier film according to any one of [1] to

[11] above, wherein the stretched film comprises, as the polyethylene layers, a first surface resin layer containing polyethylene as a main component and a polyethylene intermediate layer containing polyethylene as a main component, and the surface resin layer containing a gas barrier resin as a main component or containing polyethylene and an adhesive resin is the second surface resin layer of the stretched film, provided that when adjacent layers constituting the stretched film have the same resin composition and are indistinguishable from each other, the adjacent layers may be integrated to form a single layer.

[13] The barrier film according to any one of the above [1] to

[12] , wherein the stretched film is a uniaxially stretched film.

[14] The barrier film according to any one of the above [1] to

[13] , wherein the stretched film is a film obtained by stretching a co-extruded resin film.

[15] A laminate comprising at least the barrier film according to any one of [1] to

[14] above and a heat seal layer.

[16] The laminate according to

[15] , wherein the heat seal layer contains polyethylene as a main component, and the content of polyethylene in the entire laminate is 80% by mass or more.

[17] A packaging container comprising the laminate according to

[15] or

[16] .

[18] The packaging container according to

[17] , which is a packaging bag. [Example]

[0251] The barrier film of the present disclosure will be described in more detail below with reference to examples, but the barrier film is not limited to the following examples. In the following description, "parts by mass" will be simply referred to as "parts".

[0252] [Stretched film materials] The following materials were used in producing the stretched film. Ethylene-vinyl alcohol copolymer (EVOH) Kuraray, Eval E171B, Density: 1.14g / cm 3, Melting point: 165℃, MFR: 1.7g / 10min, Ethylene content: 44 mol% Aliphatic polyamide (aliphatic PA) BASF ULTRAMID B40, Polyamide 6 (PA6), Melting point: 220°C, relative viscosity: 4.0 Aliphatic polyamide (aliphatic PA) BASF ULTRAMID C33, Polyamide 6 / 66 (PA6 / 66), Melting point: 196°C, relative viscosity: 3.3 Crystalline semi-aromatic polyamide (semi-aromatic PA) Mitsubishi Gas Chemical Company, MX nylon (MXD6) S6007 Polymetaxylylene adipamide, Melting point: 240°C, glass transition temperature: 85°C, relative viscosity: 2.7 Amorphous semi-aromatic polyamide (semi-aromatic PA) Grivory G21, manufactured by EMS, Polyamide 6I / 6T (PA6I / 6T), Glass transition temperature: 125℃, MVR: 25cm 3 / 10 minutes Acid-modified linear low-density polyethylene (MAH-LLDPE) Arkema OREVAC 18302N, Maleic anhydride grafted linear low-density polyethylene, Density: 0.912g / cm 3 Melting point: 123°C, MFR: 1.5g / 10min Linear low-density polyethylene (LLDPE) ExxonMobil Exceed XP8656ML Ethylene-1-hexene copolymer, density: 0.916 g / cm 3 , Melting point: 121°C, MFR: 0.5g / 10min Linear low-density polyethylene (LLDPE) ExxonMobil Exceed 1327MD Ethylene-1-hexene copolymer, density: 0.927 g / cm 3 , Melting point: 123°C, MFR: 1.3g / 10min Medium Density Polyethylene (MDPE) ExxonMobil, Enable 4002MC, Density: 0.938g / cm 3 Melting point: 128°C, MFR: 0.25g / 10min Medium Density Polyethylene (MDPE) Dow Chemical, ELITE 5538G Density: 0.941g / cm 3 Melting point: 129°C, MFR: 1.3g / 10min High density polyethylene (HDPE) Dow Chemical, ELITE 5960G Density: 0.960g / cm 3 Melting point: 134°C, MFR: 0.85g / 10min ·Adhesive resin Mitsui Chemicals, Admar AT1955E, Maleic anhydride grafted modified polyethylene, Density: 0.890g / cm 3 , MFR: 2.6g / 10min Compatibilizer Dow Chemical, RETAIN 3000, Maleic anhydride grafted modified polyethylene, density: 0.870 g / cm 3

[0253] [Example 1] A blended polyethylene (A) was prepared by mixing 60 parts of LLDPE (Exceed XP8656ML) and 40 parts of MDPE (Enable 4002MC). A blended polyethylene (B) was prepared by mixing 70 parts of MDPE (Enable 4002MC) and 30 parts of LLDPE (Exceed 1327MD).

[0254] Blended polyethylene (B), A blended polyethylene (A), LLDPE (Exceed XP8656ML) and Adhesive resin (Admer AT1955E) and EVOH (Eval E171B) and The mixture was extruded into a tube shape from an extruder through a multi-layer annular die using a five-layer coextrusion inflation device, and the extrudate was inflated with air pressure while being drawn vertically to form a tubular film. The tubular film comprised an EVOH layer constituting the outer surface of the tube, an adhesive resin layer, an LLDPE layer, a blended polyethylene (A) layer, and a blended polyethylene (B) layer constituting the inner surface of the tube. The tubular film was flattened by joining its inner surfaces together, and then both ends of the tubular film in the width direction were cut off to a predetermined width to separate it into two films. Each of the resulting films was stretched 4 times in the machine direction (MD) using a stretching device to produce a 25 μm thick stretched film (uniaxially stretched film).

[0255] The stretched film thus obtained comprises, in this order, a 4 μm-thick blended polyethylene (B) layer (first polyethylene layer, first surface resin layer), a 4 μm-thick blended polyethylene (A) layer (second polyethylene layer), a 12 μm-thick LLDPE layer (third polyethylene layer), a 2.5 μm-thick adhesive resin layer, and a 2.5 μm-thick EVOH layer (second surface resin layer).

[0256] Water, isopropyl alcohol, and a small amount of hydrochloric acid were mixed, and tetraethoxysilane and a small amount of 3-glycidoxypropyltriethoxysilane were added to the mixture while cooling. To the resulting solution, a solution obtained by mixing polyvinyl alcohol, water, and isopropyl alcohol was added. In this way, a barrier coating agent was obtained.

[0257] Six types of barrier films were prepared as follows. An aluminum (AL) vapor-deposited film with a thickness of 70 nm was formed on the second surface resin layer of the stretched film by the PVD method. The barrier coating agent was spin-coated onto the surface of the AL vapor-deposited film, and the film was heated in an oven at 100°C for 8 seconds to form a barrier coating layer with a thickness of 0.3 μm. An AL vapor-deposited film with a thickness of 70 nm was formed on the barrier coating layer by the PVD method. In this way, barrier film 1 was obtained.

[0258] A 70 nm thick aluminum (AL) vapor-deposited film was formed on the second surface resin layer of the stretched film by PVD, and then a 5 nm thick aluminum oxide film was formed by PVD by first introducing oxygen into aluminum vapor and vapor-depositing it, and then a 70 nm thick AL vapor-deposited film was formed on the aluminum oxide film, thereby obtaining barrier film 2.

[0259] An alumina vapor deposition film with a thickness of 30 nm was formed on the second surface resin layer of the stretched film by PVD. The barrier coating agent was spin-coated onto the surface of the alumina vapor deposition film, and the film was heated in an oven at 100°C for 8 seconds to form a barrier coating layer with a thickness of 0.3 μm. An aluminum vapor deposition film with a thickness of 70 nm was formed on the barrier coating layer by PVD. In this way, barrier film 3 was obtained. Barrier film 4 was obtained in the same manner as barrier film 3, except that a silica vapor deposition film was formed instead of the alumina vapor deposition film.

[0260] A 30 nm thick alumina vapor deposition film was formed on the second surface resin layer of the stretched film by PVD. The above-mentioned barrier coating agent was coated on the surface of the alumina vapor deposition film by spin coating, and the resulting film was heated in an oven at 100°C for 8 seconds to form a 0.3 μm thick barrier coating layer. A 30 nm thick alumina vapor deposition film was formed on the barrier coating layer by PVD. The above-mentioned barrier coating agent was coated on the surface of the alumina vapor deposition film by spin coating, and the resulting film was heated in an oven at 100°C for 8 seconds to form a 0.3 μm thick barrier coating layer. In this way, barrier film 5 was obtained. Barrier film 6 was obtained in the same manner as barrier film 5, except that a silica vapor deposition film was formed instead of the alumina vapor deposition film.

[0261] [Example 2] Blend polyethylene (C) was prepared by mixing 70 parts MDPE (Enable 4002MC) and 30 parts HDPE (ELITE 5960G). Stretched films and six types of barrier films were produced in the same manner as in Example 1, except that blend polyethylene (C) was used instead of blend polyethylene (B). In this specification, "←" in the tables indicates that the composition of the layer in question is the same as the composition in the left-hand column, or that the thickness is the same as the thickness in the left-hand column (if there is no left-hand column, the right-most column of the previous table is used).

[0262] [Examples 3 to 8] Blend polyamide (A) was prepared by mixing 50 parts of PA6 (ULTRAMID B40) and 50 parts of MXD6 (MX Nylon S6007). Blend polyamide (B) was prepared by mixing 50 parts of crystalline semi-aromatic PA (MXD6; MX Nylon S6007) and 50 parts of amorphous semi-aromatic PA (Grivory G21). A stretched film and six types of barrier films were produced in the same manner as in Example 1, except that the resin material constituting the second surface resin layer was changed to PA6 / 66 (ULTRAMID C33), PA6 (ULTRAMID B40), blended polyamide (A), MXD6 (MX nylon S6007), blended polyamide (B), or amorphous semi-aromatic PA (Grivory G21), as shown in the table below.

[0263] [Example 9] A blended polyethylene (D) was prepared by mixing 90 parts of LLDPE (Exceed XP8656ML) and 10 parts of acid-modified LLDPE (OREVAC 18302N).

[0264] Blended polyethylene (B), A blended polyethylene (A), LLDPE (Exceed XP8656ML) and A blended polyethylene (A), a blended polyethylene (D); The mixture was extruded into a tube shape from an extruder through a multi-layer annular die using a five-layer coextrusion inflation device, and the extrudate was inflated with air pressure while being drawn vertically to form a tubular film. The tubular film comprised a blended polyethylene (D) layer constituting the outer surface of the tube, a blended polyethylene (A) layer, an LLDPE layer, a blended polyethylene (A) layer, and a blended polyethylene (B) layer constituting the inner surface of the tube. The tubular film was flattened by joining its inner surfaces together, and then both ends of the tubular film in the width direction were cut off to a predetermined width to separate it into two films. Each of the resulting films was stretched 4 times in the machine direction (MD) using a stretching device to produce a 25 μm thick stretched film (uniaxially stretched film).

[0265] The stretched film thus obtained contained, in this order, a 3 μm-thick blend polyethylene (B) layer (first polyethylene layer, first surface resin layer), a 4 μm-thick blend polyethylene (A) layer (second polyethylene layer), an 11 μm-thick LLDPE layer (third polyethylene layer), a 4 μm-thick blend polyethylene (A) layer (fourth polyethylene layer), and a 3 μm-thick blend polyethylene (D) layer (second surface resin layer). Six types of barrier films were produced in the same manner as in Example 1, except that the stretched film was used.

[0266] [Comparative Example 1] A monolayer film was obtained by extruding MDPE (ELITE 5538G) using an inflation method. The film was stretched 4 times in the machine direction (MD) using a stretching device to produce a stretched film (uniaxially stretched film) with a thickness of 25 μm. Six types of barrier films were produced in the same manner as in Example 1, except that the stretched film was used.

[0267] Comparative Example 2 The following three types of barrier films were produced using the stretched film obtained in Comparative Example 1. An aluminum (AL) vapor-deposited film with a thickness of 70 nm was formed by PVD on one side of the stretched film obtained in Comparative Example 1. In this way, barrier film 7 was obtained. An alumina vapor-deposited film with a thickness of 30 nm was formed by PVD on one side of the stretched film obtained in Comparative Example 1. The surface of the alumina vapor-deposited film was coated with the above-mentioned barrier coating agent by spin coating, and heated in an oven at 100°C for 8 seconds to form a barrier coating layer with a thickness of 0.3 μm. In this way, barrier film 8 was obtained. Barrier film 9 was obtained in the same manner as the above barrier film 8, except that a silica vapor-deposited film was formed instead of the alumina vapor-deposited film.

[0268] [Gas barrier test] The oxygen permeability (cc / (m)) of each barrier film (hereinafter also referred to as "test piece") obtained in the examples and comparative examples was measured. 2 ·day·atm)) and water vapor permeability (g / (m2 The evaluation results are shown in the tables below.

[0269] <Oxygen permeability> The oxygen permeability of the test specimen was measured in an environment of 23°C and 90% RH using an oxygen permeability measuring device (OX-TRAN2 / 20 manufactured by MOCON) in accordance with JIS K7126-2: 2006. The test specimen was placed so that the stretched film surface of the barrier film faced the oxygen supply side. A: The oxygen permeability is less than 0.2. B: Oxygen permeability is 0.2 or more and less than 0.3. C: Oxygen permeability is 0.3 or more and less than 0.6. D: Oxygen permeability is 0.6 or more and less than 1.0. E: Oxygen permeability is 1.0 or more and less than 1.5. F: Oxygen permeability is 1.5 or more and less than 3.0. G: Oxygen permeability is 3.0 or more and less than 10. H: Oxygen permeability is 10 or more.

[0270] <Water vapor permeability> The water vapor permeability of the test specimen was measured in an environment of 40°C and 90% RH using a water vapor permeability measuring device (MOCON, PERMATRAN-w 3 / 33) in accordance with JIS K7129-2: 2019. The test specimen was positioned so that the stretched film surface of the barrier film faced the water vapor supply side. A: The water vapor permeability is less than 0.2. B: The water vapor permeability is 0.2 or more and less than 0.3. C: The water vapor permeability is 0.3 or more and less than 0.6. D: Water vapor permeability is 0.6 or more and less than 1.0. E: The water vapor permeability is 1.0 or more and less than 1.5. F: Water vapor permeability is 1.5 or more and less than 3.0. G: Water vapor permeability is 3.0 or more and less than 10. H: Water vapor permeability is 10 or more.

[0271] [T-type peel test] A 20 μm thick general OPP film with one side corona treated was applied in an amount of 3 g / m to the vapor-deposited film surface or the barrier coat layer surface of each barrier film obtained in the Examples and Comparative Examples. 2 The layers were bonded together using a urethane adhesive (RU77T / H7, manufactured by Rock Paint Co., Ltd.) to prepare 15 mm wide test pieces. A T-peel test was conducted in accordance with JIS K6854-3:1999 (Adhesives - Test methods for peel adhesion strength - Part 3: T-peel) using a tensile tester (Tensilon universal testing machine, manufactured by Orientec Co., Ltd.) at a test speed of 50 mm / min and a temperature of 23°C, and the peel strength (N / 15 mm) of the vapor-deposited film against each layer was measured. The results are shown in the tables.

[0272] [Table 1]

[0273] [Table 2]

[0274] [Contents resistance] First LLDPE (Prime Polymer, SP2520, density: 0.925 g / cm 3 , melting point: 122 ° C) and a second LLDPE (Prime Polymer, SP1520, density: 0.913 g / cm 3 A multilayer film was produced by extrusion using an inflation method using a polyethylene terephthalate (LDPE) copolymer (melting point: 116°C) and an unstretched polyethylene film having a first LLDPE layer of 20 μm in thickness and a second LLDPE layer of 20 μm in thickness. This unstretched polyethylene film was used as a heat seal layer as described below.

[0275] The surface of the first LLDPE layer of the unstretched polyethylene film and the surface of the first surface resin layer of the barrier film of the example were bonded together by dry lamination using a two-component curing urethane adhesive (RU-77T / H-7, manufactured by Rock Paint Co., Ltd.), and the resulting laminate was cut to a size of 100 mm x 100 mm to obtain a laminate.

[0276] The two laminates were placed together with the heat seal layers facing each other, and the heat seal tester was used to test the adhesive at a temperature of 140°C and a pressure of 1 kgf / cm. 2 The bag was heat-sealed under conditions of 100 mm x 100 mm, 1 second crimping time, and 5 mm seal width to produce a 100 mm x 100 mm bag with an opening. 20 mL of fabric softener (product name "Malt," manufactured by Unilever) was poured into the opening, and the opening was then heat-sealed under the above conditions. The resulting sealed bag was stored in a thermostatic chamber at a temperature of 40°C and a humidity of 90% RH for 6 weeks. The sealed bag was then opened and checked for layer lifting / peeling in the laminate portion corresponding to the headspace, and for deterioration or corrosion of the vapor-deposited film. In the examples, no layer lifting / peeling or deterioration or corrosion of the vapor-deposited film was observed, demonstrating excellent resistance to the contents.

[0277] [Modification of the embodiment] Stretched films and six types of barrier films were produced in the same manner as in Examples 1 to 9, except that the thickness of the second surface resin layer was changed to 5 μm, the thickness of the third polyethylene layer to 10.5 μm, the thickness of the second polyethylene layer to 3.5 μm, and the thickness of the first surface resin layer to 3.5 μm. The results of the gas barrier property test and T-peel test in these examples were comparable to the results of the examples (Examples 1 to 9) with the corresponding layer configurations.

[0278] Stretched films and six types of barrier films were produced in the same manner as in Examples 1 and 2, except that the third polyethylene layer contained approximately 24% by mass of a compatibilizer (RETAIN 3000). Stretched films and six types of barrier films were produced in the same manner as in Examples 3 to 9, except that the third polyethylene layer contained approximately 12% by mass of a compatibilizer (RETAIN 3000). The results of the gas barrier property test and T-peel test in these examples were comparable to the results of examples with the corresponding layer configurations (Examples 1 to 9). [Explanation of symbols]

[0279] 1. Barrier film 2. Laminate 10 polyethylene layers 11 First polyethylene layer 12 Second polyethylene layer 13 Third polyethylene layer 14 Fourth polyethylene layer 20 Surface resin layer (G) or (AH) 30 Adhesive resin layer 41 First vapor deposition film 42 Second deposition film 50, 51 Adhesion improving layer 52 Protective layer 60 Adhesive layer 61 First adhesive layer 62 Second adhesive layer 70 Polyolefin oriented substrate 80 Heat seal layer 81 First heat seal layer 82 Second heat seal layer 120 tube containers 121 Tube container body 122 Head 123 Torso 124 Shoulder 125 Extraction port 126 Cap 127 Screw 128 Fusion part 129 Bottom seal

Claims

1. A barrier film, The barrier film comprises at least A stretched film; a first vapor-deposited film; a second vapor-deposited film; are provided in this order in the stacking direction, The stretched film comprises at least a polyethylene layer containing polyethylene as a main component; a surface resin layer containing a gas barrier resin as a main component or containing polyethylene and an adhesive resin; Equipped with the first vapor-deposited film is provided on the surface resin layer; Barrier film.

2. The barrier film according to claim 1 , wherein the first vapor-deposited film and the second vapor-deposited film are each independently a vapor-deposited metal film.

3. 2. The barrier film according to claim 1, wherein the first vapor-deposited film is an inorganic oxide vapor-deposited film, and the second vapor-deposited film is a metal vapor-deposited film.

4. 2. The barrier film according to claim 1, wherein the first vapor-deposited film and the second vapor-deposited film are each independently an inorganic oxide vapor-deposited film.

5. The barrier film according to claim 1 , further comprising an adhesion-improving layer between the first vapor-deposited film and the second vapor-deposited film.

6. The barrier film according to claim 5 , wherein the adhesion-improving layer is a barrier coat layer or a metal oxide film.

7. The barrier film according to claim 1 , further comprising a protective layer on a surface of the second vapor-deposited film opposite to a surface facing the first vapor-deposited film.

8. The barrier film according to claim 7 , wherein the protective layer is a barrier coat layer.

9. The stretched film has a first surface and a second surface opposite to the first surface, the first vapor-deposited film is provided on the second surface of the stretched film, the barrier film does not have a vapor-deposited film on the first surface of the stretched film; The barrier film according to claim 1 .

10. the surface resin layer is a layer containing a gas barrier resin as a main component, the surface resin layer contains, as the gas barrier resin, at least one selected from the group consisting of an ethylene-vinyl alcohol copolymer, a polyvinyl alcohol, and a polyamide; The barrier film according to claim 1 .

11. the surface resin layer is a layer containing polyethylene and an adhesive resin, the content of the polyethylene in the surface resin layer is 60% by mass or more and 95% by mass or less, and the content of the adhesive resin is 5% by mass or more and 40% by mass or less; The barrier film according to claim 1 .

12. 2. The barrier film according to claim 1, wherein the stretched film comprises, as the polyethylene layers, a first surface resin layer containing polyethylene as a main component and a polyethylene intermediate layer containing polyethylene as a main component, and the surface resin layer containing a gas barrier resin as a main component or containing polyethylene and an adhesive resin is the second surface resin layer of the stretched film, provided that when adjacent layers constituting the stretched film have the same resin composition and are indistinguishable from one another, the adjacent layers may be integrated to form a single layer.

13. 2. The barrier film according to claim 1, wherein the stretched film is a uniaxially stretched film.

14. 2. The barrier film according to claim 1, wherein the stretched film is a film obtained by stretching a co-extruded resin film.

15. The barrier film according to any one of claims 1 to 14, a heat seal layer; A laminate comprising at least

16. The laminate according to claim 15, wherein the heat seal layer contains polyethylene as a main component, and the content of polyethylene in the entire laminate is 80 mass % or more.

17. A packaging container comprising the laminate according to claim 15.

18. The packaging container according to claim 17, which is a packaging bag.

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