Laminates and packaging containers

Abstract

The present invention provides a laminate comprising a barrier layer consisting of a stretched film containing a polyolefin layer and a vapor-deposited film, wherein the laminate exhibits excellent gas barrier properties and excellent adhesion between the stretched film and the vapor-deposited film. [Solution] A laminate comprising, in this order, a heat seal layer, a first vapor-deposited film, an adhesive layer, and a barrier layer, wherein the heat seal layer mainly contains polyolefin, and the barrier layer comprises a stretched film and a second vapor-deposited film. (1) The stretched film comprises at least a polyolefin layer containing polyolefin as the main component, and a surface resin layer containing a gas barrier resin as the main component, or a polyolefin and an adhesive resin, and the second vapor-deposited film is provided on the surface resin layer, or (2) The stretched film is a polyolefin-based stretched film, and an anchor coat layer containing a resin material having polar groups is provided between the stretched film and the second vapor-deposited film. Laminated structure.

Description

[Technical Field]

[0001] This disclosure relates to laminates and packaging containers. [Background technology]

[0002] Packaging containers are used to contain contents such as liquids and powders. Packaging containers are made using laminates comprising a base layer and a heat-seal layer (see, for example, Patent Document 1). For example, polyolefin film is widely used as a heat-seal layer because it has flexibility, transparency, and excellent heat-sealability. Also, biaxially oriented polyester film is widely used as a base layer because it has excellent strength and heat resistance.

[0003] In recent years, there has been a growing demand for recycling packaging containers from the perspective of reducing environmental impact. From the standpoint of recyclability, it is preferable that the base layer and the heat-seal layer are each made of polyolefin. For example, Patent Document 1 proposes that the base layer and the heat-seal layer be made of polyethylene. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-55156 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The inventors investigated the production of a packaging container using a laminate comprising a stretched polyolefin film as a base layer. However, because stretched polyolefin films have low gas barrier properties, such packaging containers did not have sufficient gas barrier properties. Therefore, the inventors investigated using a barrier layer comprising a vapor-deposited film on a stretched polyolefin film as the base layer. However, this barrier layer still sometimes lacked sufficient gas barrier properties, and the adhesion between the stretched polyolefin film and the vapor-deposited film was sometimes insufficient.

[0006] One object of this disclosure is to provide a laminate comprising a barrier layer having a stretched film containing a polyolefin layer and a vapor-deposited film, which exhibits excellent gas barrier properties and excellent adhesion between the stretched film and the vapor-deposited film. [Means for solving the problem]

[0007] One embodiment of the laminate of the present disclosure comprises, in this order, at least a heat seal layer, a first vapor-deposited film, an adhesive layer, and a barrier layer, wherein the heat seal layer mainly contains polyolefin, and the barrier layer comprises a stretched film and a second vapor-deposited film. (1) The stretched film comprises at least a polyolefin layer containing polyolefin as the main component, and a surface resin layer containing a gas barrier resin as the main component, or a polyolefin and an adhesive resin, and the second vapor-deposited film is provided on the surface resin layer, or (2) The stretched film is a polyolefin-based stretched film, and an anchor coat layer containing a resin material having polar groups is provided between the stretched film and the second vapor-deposited film. [Effects of the Invention]

[0008] According to this disclosure, a laminate comprising a barrier layer consisting of a stretched film containing a polyolefin layer and a vapor-deposited film can be provided, which exhibits excellent gas barrier properties and excellent adhesion between the stretched film and the vapor-deposited film. This laminate is useful, for example, as a packaging material for producing packaging containers with excellent gas barrier properties. [Brief explanation of the drawing]

[0009] [Figure 1A] Figure 1A is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 1B] Figure 1B is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 1C] Figure 1C is a schematic cross-sectional view showing one embodiment of a barrier film. [Figure 2] Figure 2 is a schematic cross-sectional view showing one embodiment of the laminate. [Figure 3] Figure 3 is a schematic cross-sectional view showing one embodiment of the laminate. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below. This disclosure can be implemented in many different forms and is not construed as being limited to the embodiments described below. The drawings may schematically represent the width, thickness, and shape of each layer, etc., compared to the embodiments, in order to clarify the explanation, but these are merely examples and do not limit the interpretation of this disclosure. In this specification and in each figure, elements similar to those already described in the previously shown figures are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0011] In this disclosure, if there are multiple candidate upper limits and multiple candidate lower limits for a certain parameter, the numerical range of that parameter may be constructed by combining any one candidate upper limit and any one candidate lower limit. Examples of such parameters include physical properties, component content, and layer thickness. As an example, let's consider the statement, "Parameter B is preferably A1 or higher, more preferably A2 or higher, and even more preferably A3 or higher. Parameter B is preferably A4 or lower, more preferably A5 or lower, and even more preferably A6 or lower." In this example, the numerical range of parameter B may be A1 or higher and A4 or lower, A1 or higher and A5 or lower, A1 or higher and A6 or lower, A2 or higher and A4 or lower, A2 or higher and A5 or lower, A2 or higher and A6 or lower, A3 or higher and A4 or lower, A3 or higher and A5 or lower, and A3 or higher and A6 or lower.

[0012] In this specification, polyethylene refers to a polymer in which the content of ethylene-derived structural units in the total repeating structural units exceeds 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 above content is measured by NMR spectroscopy.

[0013] 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 ethylenically unsaturated monomers 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.

[0014] In the present specification, examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymers, and ethylene-(meth)acrylate copolymers. From the viewpoint of reducing environmental load, biomass-derived polyethylene (hereinafter also referred to as "biomass polyethylene") or mechanically recycled or chemically recycled polyethylene (hereinafter also referred to as "recycled polyethylene") may be used as polyethylene.

[0015] In the present specification, the densities of polyethylene are as follows. The density of 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 is preferably 0.960 g / cm 3 The density of medium-density polyethylene is preferably 0.930 g / cm 3 more than 0.930 g / cm and not more than 0.945 g / cm 3 The density of low-density polyethylene is preferably 0.860 g / cm 3 or more and 0.930 g / cm 3 or less, more preferably 0.900 g / cm 3 or more and 0.930 g / cm 3 or less. The density of linear low-density polyethylene is preferably 0.860 g / cm 3 or more and 0.930 g / cm 3 or less, more preferably 0.900 g / cm 3 or more and 0.930 g / cm 3 or less. Note that polyethylene having a density of less than 0.900 g / cm 3 , preferably 0.860 g / cm 3 or more and less than 0.900 g / cm 3 is sometimes particularly referred to as ultra-low-density polyethylene. In this case, the density of low-density polyethylene is preferably 0.900 g / cm 3 or more and 0.930 g / cm 3 or less, and the density of linear low-density polyethylene is preferably 0.900 g / cm3 More than 0.930g / cm 3 The following applies. In this specification, the density of polyethylene is measured in accordance with JIS K7112-2:2023 (density gradient pipe method, 23°C).

[0016] Low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene by high-pressure polymerization (high-pressure low-density polyethylene). Linear low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene and a small amount of α-olefin by polymerization using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst.

[0017] Examples of linear low-density polyethylene include ethylene-α-olefin copolymers. Examples of α-olefins include the α-olefins with 3 to 20 carbon atoms mentioned above, with α-olefins with 3 to 8 carbon atoms being preferred, and α-olefins with 4 to 8 carbon atoms being more preferred. 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 comonomers, and further comonomers may be used. For example, linear low-density polyethylene produced using a metallocene catalyst is preferred.

[0018] Polyethylenes with different densities or branching can be obtained by appropriately selecting a 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 to carry out polymerization in one or more stages using one of the following methods: gas-phase polymerization, slurry polymerization, solution polymerization, or high-pressure ionic polymerization.

[0019] In this specification, polypropylene refers to a propylene homopolymer, or a polymer in which the proportion of propylene-derived structural units in the total repeating structural units is greater than the proportion of structural units derived from any comonomer. In this polymer, the proportion of propylene-derived structural units may be, for example, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more in the total repeating structural units. The above proportion is measured by NMR spectroscopy.

[0020] Polypropylene may be any of the following: propylene homopolymer (homopolypropylene), propylene random copolymer (random polypropylene) such as propylene-α-olefin random copolymer, or propylene block copolymer (block polypropylene) such as propylene-α-olefin block copolymer, or a mixture of two or more selected from these. From the viewpoint of reducing environmental impact, biomass-derived polypropylene or mechanically or chemically recycled polypropylene may be used as the polypropylene. Examples of α-olefins include α-olefins other than propylene that have 2 to 20 carbon atoms, specifically ethylene, 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, with ethylene, 1-butene, 1-pentene, and 1-hexene being preferred.

[0021] In this specification, the density of polypropylene is, for example, 0.88 g / cm³. 3 More than 0.92g / cm 3 The following applies. In this specification, the density of polypropylene is measured in accordance with JIS K7112-2:2023 (density gradient pipe method, 23°C).

[0022] In this specification, the melt flow rate (MFR) of polyethylene in the form of the stretched film (X) described later 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, 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 polyethylene 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.

[0023] In this specification, the melt flow rate (MFR) of polyolefins such as polyethylene and polypropylene in the form of the stretched film (Y) described later is preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more, even more preferably 1.5 g / 10 min or more, preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 6 g / 10 min or less, for example, 0.1 g / 10 min or more and 50 g / 10 min or less. In this specification, the MFR of polyolefins is measured by Method A under a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature of the MFR is set according to the melting point of the polyolefin, etc., and is 190°C for polyethylene and 230°C for polypropylene.

[0024] In this specification, each component mentioned in the following description (for example, polyolefins such as polyethylene and polypropylene, α-olefins, resin materials such as gas barrier resins, adhesive resins, and additives) may be used individually or in combination of two or more.

[0025] In this specification, the terms "film" and "sheet" may be used, but "film" and "sheet" are not distinguished from each other solely on the basis of their names. In this specification, "multilayer" means two or more layers. In this specification, if adjacent layers constituting a film have the same resin composition and are indistinguishable from one another, the adjacent layers may be integrated to form a single layer.

[0026] In this specification, "main component" in a layer or film means a component whose content in that layer or film exceeds 50% by mass. The content is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0027] [Barrier layer] The barrier layer provided by the laminate of this disclosure will be described below. The barrier layer comprises a stretched film and a second vapor-deposited film. (1) In one embodiment, the stretched film comprises at least a polyolefin layer containing polyolefin as the main component, and a surface resin layer containing a gas barrier resin as the main component, or a polyolefin and an adhesive resin. Hereinafter, the stretched film of this embodiment will also be referred to as "stretched film (1)". The second vapor-deposited film is provided on the surface resin layer. (2) In one embodiment, the stretched film is a polyolefin-based stretched film. Hereinafter, the stretched film of this embodiment will also be referred to as "stretched film (2)". An anchor coat layer containing a resin material having polar groups is provided between the stretched film (2) and the second vapor-deposited film. The following explanation also applies to barrier films corresponding to barrier layers.

[0028] <Stretched film (1)> Examples of stretched film (1) include stretched films (X) and (Y), which are described below. In the following description, when referring to matters common to stretched films (X) and (Y), it will simply be written as "stretched film (1)".

[0029] The stretched film (X) is at least, A polyethylene layer containing polyethylene as the main component, A surface resin layer containing a gas barrier resin as the main component, or containing polyethylene and an adhesive resin, It is equipped with. The stretched film (X) may have two or more polyethylene layers.

[0030] In one embodiment, the stretched film (X) comprises at least, A first surface resin layer containing polyethylene as the main component, A polyethylene intermediate layer containing polyethylene as the main component, A second surface resin layer containing a gas barrier resin as the main component, or containing polyethylene and an adhesive resin, The stacking direction is arranged in this order. The stretched film (X) may have two or more polyethylene intermediate layers.

[0031] The stretched film (Y) is at least, A polyolefin layer containing polyolefin as the main component, A surface resin layer containing a gas barrier resin as the main component, or containing polyolefin and adhesive resin, It is equipped with. The stretched film (Y) may have two or more polyolefin layers.

[0032] In one embodiment, the stretched film (Y) comprises at least, A first surface resin layer containing polyolefin as the main component, A polyolefin intermediate layer containing polyolefin as the main component, A second surface resin layer containing a gas barrier resin as the main component, or containing polyolefin and an adhesive resin, The stacking direction is arranged in this order. The stretched film (Y) may have two or more polyolefin intermediate layers.

[0033] In the following description, a surface resin layer containing a gas barrier resin as the main component will also be referred to as "surface resin layer (G)," and a surface resin layer containing polyolefin (e.g., polyethylene or polypropylene) and an adhesive resin will also be referred to as "surface resin layer (AH)." In the following description, a stretched film (1) having a surface resin layer (G) will also be referred to as "stretched film of the first embodiment," and a stretched film (1) having a surface resin layer (AH) will also be referred to as "stretched film of the second embodiment."

[0034] The stretched films (X) and (Y) of the first embodiment are, in one embodiment, at least, A first surface resin layer containing polyethylene as the main component, A polyethylene intermediate layer containing polyethylene as the main component, A second surface resin layer containing a gas barrier resin as its main component, This is a polyethylene-based stretched film that possesses the following features in this order. The stretched film (Y) of the first embodiment is, in one embodiment, A first surface resin layer containing polypropylene as the main component, A polypropylene intermediate layer containing polypropylene as the main component, A second surface resin layer containing a gas barrier resin as its main component, This is a polypropylene stretched film that possesses the following features in this order.

[0035] The stretched films (X) and (Y) of the second embodiment are, in one embodiment, at least, A first surface resin layer containing polyethylene as the main component, A polyethylene intermediate layer containing polyethylene as the main component, A second surface resin layer containing polyethylene and an adhesive resin, This is a polyethylene-based stretched film that possesses the following features in this order. The stretched film (Y) of the second embodiment comprises, in one embodiment, at least, A first surface resin layer containing polypropylene as the main component, A polypropylene intermediate layer containing polypropylene as the main component, A second surface resin layer containing polypropylene and an adhesive resin, This is a polypropylene stretched film that possesses the following features in this order.

[0036] In one embodiment, the stretched film (Y) comprises at least, A first surface resin layer containing polyethylene as the main component, A polyethylene intermediate layer containing polyethylene as the main component, A second surface resin layer containing a gas barrier resin as the main component, or containing polyethylene and an adhesive resin, This is a polyethylene stretched film that has the following features in this order: The polyethylene in at least one layer selected from the group consisting of a first surface resin layer, a polyethylene intermediate layer, and a second surface resin layer, before stretching, contains at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, or 0.930 g / cm³ 3 Super 0.960g / cm 3 It has the following density:

[0037] The stretched film (1) of the first embodiment may further include an adhesive resin layer between the polyolefin layer and the surface resin layer (G). In one embodiment, the stretched film (1) of the first embodiment may comprise, in this order, a first polyolefin layer as the first surface resin layer, a second polyolefin layer, a third polyolefin layer, an adhesive resin layer, and a surface resin layer (G) as the second surface resin layer. Hereinafter, the stretched film (1) of this embodiment will also be referred to as "stretched film α". The compositions of the first to third polyolefin layers may be the same or different. The thicknesses of the first to third polyolefin layers may be the same or different. In the case of stretched film (X), the polyolefin layer shall be read as a polyethylene layer.

[0038] In one embodiment, the stretched film (1) of the second embodiment may comprise, in this order, a first polyolefin layer as a first surface resin layer, a second polyolefin layer, a third polyolefin layer, a fourth polyolefin layer, and a surface resin layer (AH) as a second surface resin layer. Hereinafter, the stretched film (1) of this embodiment will also be referred to as "stretched film β". The compositions of the first to fourth polyolefin layers may be the same or different. The thicknesses of the first to fourth polyolefin layers may be the same or different. In the case of stretched film (X), the polyolefin layers may be read as polyethylene layers.

[0039] The stretched film (1) 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 (1). The second surface resin layer constitutes the second surface of the stretched film (1). The second vapor-deposited film is provided on the second surface of the stretched film (1).

[0040] The stretched film (1) has a multilayer structure of two or more layers. The number of layers of the stretched film (1) is two or more, preferably three or more, preferably nine or fewer, more preferably seven or fewer, for example, two to nine layers. Specifically, the number of layers of the stretched film (1) may be three, five, seven, or nine. The stretched film (1) having a multilayer structure has an excellent balance of, for example, gas barrier properties, strength, rigidity, heat resistance, transparency, and printability.

[0041] The content of polyolefin (for example, polyethylene or polypropylene; in the case of stretched film (X), polyethylene) in the stretched film (1) is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 75% by mass or more, and particularly preferably 80% by mass or more. A laminate (or packaging container) comprising such a stretched film (1) has excellent recyclability, for example.

[0042] The stretched film (1) is a film that has undergone a stretching treatment. Stretching can improve, for example, the film's strength, rigidity, heat resistance, transparency, and printability. The stretching treatment may be uniaxial stretching or biaxial stretching. Biaxial stretching may be sequential biaxial stretching using methods such as the tenter frame method, or simultaneous biaxial stretching. When stretching in the machine direction (film flow direction, longitudinal direction, MD direction), the stretching ratio is preferably 2 times or more, more preferably 3 times or more, preferably 15 times or less, more preferably 10 times or less, and may be, for example, 7 times or less, or for example, 2 times to 15 times. When stretching in the width direction (direction perpendicular to the MD direction, transverse direction, TD direction), the stretching ratio is preferably 2 times or more, more preferably 3 times or more, preferably 15 times or less, more preferably 10 times or less, and may be, for example, 7 times or less, or for example, 2 times to 15 times.

[0043] Stretched film (1) is, for example, a uniaxially stretched film, specifically a film uniaxially stretched in the MD direction (MDO film). Stretched film (1) is, for example, a biaxially stretched film, specifically a film biaxially stretched in the MD direction and the TD direction. Stretched film (X) is, in one embodiment, a uniaxially stretched film, specifically a film uniaxially stretched in the MD direction (MDO film). Stretched film (Y) is, in one embodiment, a biaxially stretched film, specifically a film biaxially stretched in the MD direction and the TD direction.

[0044] The thickness of the stretched film (1) is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, and particularly preferably 40 μm or less, for example, 5 μm or more and 200 μm or less. A stretched film (1) with a thickness of the lower limit or more has excellent properties such as strength, rigidity and heat resistance. A stretched film (1) with a thickness of the upper limit or less has excellent properties such as processability. In this specification, the thickness of the film and each layer is the average value of 10 thicknesses measured in an SEM image obtained by scanning electron microscopy (SEM) observation of a cross-section perpendicular to the film surface.

[0045] The stretched film (1) can be produced, for example, by forming films of the materials constituting each layer to create a laminated film, and then stretching the laminated film. Examples of film formation methods include the inflation method and the T-die casting method. In the case of the stretched film (X), the inflation method is preferred, while in the case of the stretched film (Y), the T-die casting method is preferred from the viewpoint of productivity.

[0046] In one embodiment, the stretched film (1) is a stretched film of a co-extruded resin film. In one embodiment, the stretched film (1) is a film obtained by co-extruding a material constituting a polyolefin layer, a material constituting an adhesive resin layer if the stretched film (1) includes an adhesive resin layer, and a material constituting a surface resin layer (G) or (AH) in this order in the lamination direction using an inflation method or a T-die-casting method, and then stretching the resulting laminated film.

[0047] In one embodiment, the stretched film (1) is a film obtained by co-extruding a material constituting a first surface resin layer, a material constituting a polyolefin intermediate layer, a material constituting an adhesive resin layer if the stretched film (1) includes an adhesive resin layer, and a material constituting a second surface resin layer in this order in the lamination direction using an inflation method or a T-die-casting method, and then stretching the resulting laminated film.

[0048] One embodiment of the co-extrusion T-die casting method is described below. A laminated film is obtained by supplying the materials for forming each layer to each extruder and performing co-extrusion T-die casting.

[0049] A manufacturing example of a stretched film (Y) according to the first embodiment will be described. In the case of a polyethylene stretched film, for example, in each extruder, the extrusion temperature for the first surface resin layer, the extrusion temperature for the polyethylene intermediate layer, the extrusion temperature for the adhesive resin layer, and the extrusion temperature for the second surface resin layer containing an ethylene-vinyl alcohol copolymer are set to 220°C or more and 240°C or less. In the case of a polyethylene stretched film, for example, in each extruder, the extrusion temperature for the first surface resin layer is set to 220°C or more and 260°C or less, the extrusion temperature for the polyethylene intermediate layer is set to 220°C or more and 260°C or less, the extrusion temperature for the adhesive resin layer is set to 220°C or more and 270°C or less, and the extrusion temperature for the second surface resin layer containing polyamide is set to 260°C or more and 280°C or less.

[0050] A manufacturing example of a stretched film (Y) according to the first embodiment will be described. In the case of a polypropylene stretched film, for example, in each extruder, the extrusion temperature for the first surface resin layer is set to 260°C or more and 280°C or less, the extrusion temperature for the polypropylene intermediate layer is set to 260°C or more and 280°C or less, the extrusion temperature for the adhesive resin layer is set to 250°C or more and 270°C or less, and the extrusion temperature for the second surface resin layer containing ethylene-vinyl alcohol copolymer is set to 220°C or more and 240°C or less. In the case of a polypropylene stretched film, for example, in each extruder, the extrusion temperature for the first surface resin layer is set to 260°C or more and 280°C or less, the extrusion temperature for the polypropylene intermediate layer is set to 260°C or more and 280°C or less, the extrusion temperature for the adhesive resin layer is set to 260°C or more and 280°C or less, and the extrusion temperature for the second surface resin layer containing polyamide is set to 260°C or more and 280°C or less.

[0051] A manufacturing example of a stretched film (Y) according to a second embodiment will be described. In the case of a polyethylene stretched film, for example, in each extruder, the extrusion temperature for the first surface resin layer, the extrusion temperature for the polyethylene intermediate layer, and the extrusion temperature for the second surface resin layer containing polyethylene and adhesive resin are set to 220°C or more and 240°C or less. In the case of a polypropylene stretched film, for example, in each extruder, the extrusion temperature for the first surface resin layer is set to 260°C or more and 280°C or less, the extrusion temperature for the polypropylene intermediate layer is set to 260°C or more and 280°C or less, and the extrusion temperature for the second surface resin layer containing polypropylene and adhesive resin is set to 240°C or more and 260°C or less. Note that these extrusion temperatures in the extruder are merely examples and can be changed as appropriate.

[0052] The stretched film (1) and the barrier layer may be surface-treated. Such stretched film (1) and barrier layer may have excellent adhesion to other layers, for example. Examples of surface treatment methods include physical treatment and chemical treatment. Examples of physical treatments include corona treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment. Examples of chemical treatments include oxidation treatment using chemicals.

[0053] ≪Polyethylene layer of stretched film (X)≫ The polyethylene layer of the stretched film (X) is, for example, a polyethylene intermediate layer located between the first surface resin layer and the second surface resin layer in the stretched film (X), and / or the first surface resin layer.

[0054] The polyethylene layer contains polyethylene as its main component. From the viewpoint of the strength and heat resistance of the stretched film (X), high-density polyethylene and medium-density polyethylene are preferred. From the viewpoint of the film-forming properties and processability of the stretched film (X), linear low-density polyethylene and medium-density polyethylene are preferred.

[0055] The melting point (Tm) of 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, particularly preferably 120°C or higher, and preferably 140°C or lower, for example, 100°C or higher and 140°C or lower, from the viewpoint of heat resistance. 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 (3.(2) (however, test specimens conditioned according to a cooling rate of 10°C / min)).

[0056] 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, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The barrier layer can be suitably used as a base layer constituting a packaging material such as a polyethylene-based monomaterial packaging material.

[0057] The polyethylene layer may contain resin materials other than polyethylene. Examples of such resin materials include polyolefins other than polyethylene, such as polypropylene, polyester, polyamide, (meth)acrylic resin, vinyl resin, cellulose resin, and ionomer resin.

[0058] The polyethylene layer may contain additives. Examples of additives include crosslinking agents, antioxidants, UV absorbers, light stabilizers, antiblocking agents, slip agents, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins.

[0059] In the stretched film (X) of the first embodiment, the polyethylene layer may further contain a compatibilizer. By including a compatibilizer in the polyethylene layer, the miscibility between the gas barrier resin and polyethylene can be improved when the stretched film (X) and the barrier layer are heated and melted for recycling. This effectively suppresses the deterioration of the physical properties of polyethylene after recycling, and also effectively suppresses the deterioration of the transparency of polyethylene.

[0060] Examples of compatibilizers include acid-modified polyolefins, and acid-modified polyethylene is preferred from the viewpoint of recyclability. Examples of acid-modified polyolefins include modified polyolefins 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. Specifically, unsaturated carboxylic acid compound-modified polyethylene is preferred as a compatibilizer, and maleic anhydride-modified polyethylene is more preferred.

[0061] When the polyethylene layer contains a compatibilizer, the compatibilizer content 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, preferably 25% by mass or less, more preferably 20% by mass or less, and 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 (X) comprises two or more polyethylene layers, at least one polyethylene layer may contain a compatibilizer. When the stretched film (X) comprises two or more polyethylene layers, the basis for the compatibilizer content is the total mass of all polyethylene layers.

[0062] 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 content in the stretched film (X). 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 content in the stretched film (X). 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 content in the stretched film (X).

[0063] The thickness of the polyethylene layer in the stretched film (X) is preferably 3 μm or more, more preferably 8 μm or more, even more preferably 13 μm or more, preferably 180 μm or less, more preferably 80 μm or less, even more preferably 40 μm or less, and particularly preferably 30 μm or less, for example, 3 μm or more and 180 μm or less. A stretched film (X) having a polyethylene layer with a thickness equal to or greater than the lower limit has excellent properties such as strength, rigidity, heat resistance and recyclability. A stretched film (X) having a polyethylene layer with a thickness equal to or less than the upper limit has excellent properties such as processability. If the stretched film (X) has two or more polyethylene layers, the above "thickness" means the sum of the thicknesses of each polyethylene layer.

[0064] The thickness of the polyethylene layer is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, even more preferably 70% or more, particularly preferably 80% or more, preferably 98% or less, more preferably 94% or less, and even more preferably 90% or less, for example, 40% to 98%. If the stretched film (X) comprises two or more polyethylene layers, the above "thickness" means the sum of the thicknesses of each polyethylene layer.

[0065] The stretched film (X) may have one polyethylene layer or two or more layers.

[0066] In a stretched film (X) comprising two or more polyethylene layers, the density of each polyethylene layer may be the same or different. For example, the stretched film (X) may have a density gradient in each polyethylene layer. A stretched film (X) having a density gradient in each polyethylene layer exhibits excellent strength, rigidity, heat resistance, and stretchability in the film before stretching.

[0067] In a stretched film (X) having a density gradient in each polyethylene layer, it is preferable that the absolute value of the density difference between any adjacent polyethylene layers is small. For example, the absolute value of the density difference should be 0.050 g / cm³. 3 Preferably, 0.040 g / cm³ 3 More preferably, 0.030 g / cm³ 3 More preferably, 0.020 g / cm³ 3 The following applies: Such a stretched film (X) can effectively suppress, for example, the occurrence of delamination at the interface of each polyethylene layer. The density of the polyethylene layer is measured in accordance with JIS K7112-2:2023 (density gradient pipe method, 23°C).

[0068] In one embodiment, the stretched film (X) comprises a polyethylene layer as a first surface resin layer. The first surface resin layer in the film before stretching is, for example, a layer containing medium-density polyethylene, preferably a layer mainly containing medium-density polyethylene, 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.

[0069] The content of medium-density polyethylene in the first surface resin layer of the film before stretching is preferably 45% by mass or more, more preferably 55% by mass or more, even more preferably 65% ​​by mass or more, preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 75% by mass or less, for example, 45% by mass or more and 95% by mass or less.

[0070] The total content of linear low-density polyethylene and high-density polyethylene in the first surface resin layer of the film before stretching is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 25% by mass or more, 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.

[0071] The thickness of the first surface resin layer in the stretched film (X) is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 1.5 μm or more, 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, preferably 35% or less, more preferably 30% or less, and even more preferably 25% or less, relative to the thickness of the stretched film (X), for example, 3% or more and 35% or less.

[0072] The ratio of the thickness of the second surface resin layer to the thickness of the first surface resin layer is preferably 0.6 to 1.5 from the viewpoint of maintaining the symmetry of the stretched film (X) and suppressing the occurrence of curl.

[0073] The film α1 and the stretched film (X)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.

[0074] The film β1 and the stretched film (X)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.

[0075] 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 its main component. Such films and their stretched films (X) have excellent processability, excellent interlayer adhesion strength between each polyethylene layer, and can effectively suppress the occurrence of delamination. A stretched film (X) with a high density first polyethylene layer has excellent heat resistance and can suppress the occurrence of curl caused by the density difference between the first surface resin layer and the second surface resin layer.

[0076] In one embodiment of films α1 and β1, the first polyethylene layer contains medium-density polyethylene and linear low-density polyethylene. Such films and their stretched films (X) have, for example, superior processability. In another embodiment of films α1 and β1, the first polyethylene layer contains medium-density polyethylene and high-density polyethylene. Such films and their stretched films (X) have, for example, superior heat resistance and can sufficiently suppress the occurrence of curl. The details of the first polyethylene layer are the same as those of the first surface resin layer described above.

[0077] 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, it is a layer containing linear low-density polyethylene and medium-density polyethylene, or from the viewpoint of stretchability, it is a layer mainly containing linear low-density polyethylene.

[0078] In film β1, the fourth polyethylene layer is, for example, a layer containing linear low-density polyethylene, and preferably, from the viewpoint of rigidity, it is a layer containing linear low-density polyethylene and medium-density polyethylene, or from the viewpoint of stretchability, it is a layer mainly containing linear low-density polyethylene.

[0079] 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, 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.

[0080] The content of medium-density polyethylene 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, 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.

[0081] In films α1 and β1, the third polyethylene layer is, for example, a layer mainly composed of linear low-density polyethylene. In film α1, the third polyethylene layer may further contain the compatibilizer described above.

[0082] 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, may be 99% by mass or less, may be 97% by mass or less, may be 95% by mass or less, or may be 90% by mass or less.

[0083] When the third polyethylene layer of film α1 contains a compatibilizer, the compatibilizer content 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, 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.

[0084] The thickness of the second polyethylene layer of stretched film (X)α, and the second and fourth polyethylene layers of stretched film (X)β, are each independently preferably 5% or more, more preferably 10% or more, even more preferably 15% or more, preferably 35% or less, more preferably 30% or less, even more preferably 25% or less, with respect to the thickness of stretched film (X), for example, 5% or more and 35% or less.

[0085] In stretched films (X)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, preferably 80% or less, more preferably 70% or less, even more preferably 60% or less, for example, 30% to 80% of the thickness of the stretched film (X).

[0086] In the stretched film (X)α, the thickness of the adhesive resin layer is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, preferably 20% or less, more preferably 18% or less, even more preferably 15% or less, for example, 2% to 20%.

[0087] In the stretched film (X)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 maintaining the symmetry of the stretched film (X) and suppressing the occurrence of curl.

[0088] In the stretched film (X)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 maintaining the symmetry of the stretched film (X) and suppressing the occurrence of curl.

[0089] In the stretched film (X)β, the ratio of the thickness of the second polyethylene layer to the thickness of the fourth polyethylene layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of maintaining the symmetry of the stretched film (X) and suppressing the occurrence of curl.

[0090] In the stretched film (X)β, the ratio of the thickness of the surface resin layer (AH) to the thickness of the first polyethylene layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of maintaining the symmetry of the stretched film (X) and suppressing the occurrence of curl.

[0091] The relative densities of each polyethylene layer in stretched film (X)α and β are not particularly limited, as long as they do not impair the stretchability of the film, or the heat resistance, strength, rigidity, and interlayer adhesion of the stretched film (X). In one embodiment, the stretched film (X)α and β have a higher density in the second polyethylene layer than in the third polyethylene layer, and a higher density in the first polyethylene layer than in the second polyethylene layer. Such a stretched film (X) tends to have superior heat resistance, strength, rigidity, and curl suppression. In one embodiment, the stretched film (X)α and β have a higher density in the second polyethylene layer than in the third polyethylene layer, and a lower density in the first polyethylene layer than in the second polyethylene layer. In one embodiment, the stretched film (X)α and β have a lower density in the second polyethylene layer than in the third polyethylene layer, and a higher density in the first polyethylene layer than in the second polyethylene layer.

[0092] In one embodiment, the stretched film (X) comprises two or more polyethylene layers, optionally an adhesive resin layer, and a surface resin layer (G) or (AH) in this order, wherein the density of the polyethylene layer furthest from the surface resin layer (G) or (AH) is preferably higher than the density of the polyethylene layer closest to the surface resin layer (G) or (AH). Such a stretched film (X) can, for example, suppress the occurrence of curling.

[0093] ≪Polyolefin layer of stretched film (Y)≫ The polyolefin layer of the stretched film (Y) is, for example, a polyolefin intermediate layer located between the first surface resin layer and the second surface resin layer in the stretched film (Y), and / or the first surface resin layer.

[0094] The polyolefin layer contains polyolefin as its main component. Examples of polyolefins include polyethylene, polypropylene, polybutene, and polymethylpentene. Among these, polyethylene and polypropylene are preferred. As for the polyolefin layer, for example, a polyethylene layer containing polyethylene as its main component and a polypropylene layer containing polypropylene as its main component are preferred.

[0095] The polyolefin (e.g., polyethylene or polypropylene) content in the polyolefin 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, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The barrier layer can be suitably used as a base layer constituting a packaging material such as a polyolefin-based monomaterial packaging material.

[0096] The polyolefin layer may also contain resin materials other than polyolefin. The polyolefin layer may contain the above-mentioned additives.

[0097] In the stretched film (Y) of the first embodiment, the polyolefin layer may further contain a compatibilizer. By including a compatibilizer in the polyolefin layer, the miscibility between the gas barrier resin and the polyolefin can be improved when the stretched film (Y) and the barrier layer are heated and melted for recycling. This effectively suppresses the deterioration of the physical properties of the polyolefin after recycling, and also effectively suppresses the deterioration of the transparency of the polyolefin.

[0098] Examples of compatibilizers include acid-modified polyolefins, and from the viewpoint of recyclability, acid-modified polyethylene and acid-modified polypropylene are preferred. 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. Specifically, unsaturated carboxylic acid compound-modified polyethylene and unsaturated carboxylic acid compound-modified polypropylene are preferred as compatibilizers, and maleic anhydride-modified polyethylene and maleic anhydride-modified polypropylene are more preferred.

[0099] When the polyolefin layer contains a compatibilizer, the content of the compatibilizer in the polyolefin layer is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, preferably 25% by mass or less, more preferably 20% by mass or less, and 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 (Y) comprises two or more polyolefin layers, at least one polyolefin layer may contain a compatibilizer. When the stretched film (Y) comprises two or more polyolefin layers, the basis for the content of the compatibilizer is the total mass of all polyolefin layers.

[0100] When the polyolefin layer contains a compatibilizer, the content of the compatibilizer in the polyolefin 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 content in the stretched film (Y). For example, when the gas barrier resin is an ethylene-vinyl alcohol copolymer, the content of the compatibilizer in the polyolefin 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 content in the stretched film (Y). For example, when the gas barrier resin is a polyamide, the content of the compatibilizer in the polyolefin layer is preferably 25 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the polyamide content in the stretched film (Y).

[0101] The thickness of the polyolefin layer in the stretched film (Y) is preferably 3 μm or more, more preferably 8 μm or more, even more preferably 13 μm or more, preferably 180 μm or less, more preferably 80 μm or less, even more preferably 40 μm or less, and particularly preferably 30 μm or less, for example, 3 μm or more and 180 μm or less. A stretched film (Y) having a polyolefin layer with a thickness equal to or greater than the lower limit has excellent properties such as strength, rigidity, heat resistance and recyclability. A stretched film (Y) having a polyolefin layer with a thickness equal to or less than the upper limit has excellent properties such as processability. If the stretched film (Y) has two or more polyolefin layers, the above "thickness" means the sum of the thicknesses of each polyolefin layer.

[0102] The thickness of the polyolefin layer is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, even more preferably 70% or more, and particularly preferably 80% or more, relative to the thickness of the stretched film (Y). For example, it may be 98% or less, 94% or less, or 90% or less, for example, 40% to 98%. If the stretched film (Y) comprises two or more polyolefin layers, the above "thickness" means the sum of the thicknesses of each polyolefin layer.

[0103] The stretched film (Y) may have one polyolefin layer or two or more layers.

[0104] The first surface resin layer may further contain particles. By including particles in the first surface resin layer, for example, the antiblocking or slipperiness of the stretched film (Y) can be improved. The second surface resin layer (surface resin layer (G) or (AH)) is preferably free of particles from the viewpoint of vapor deposition film formation.

[0105] Examples of particles include inorganic compound-based antiblocking agents and resin particle-based antiblocking agents. Specific examples of inorganic compound-based antiblocking agents include oxides such as silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, and zinc oxide; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; carbonates such as magnesium carbonate and calcium carbonate; sulfates such as calcium sulfate and barium sulfate; silicates such as magnesium silicate, aluminum silicate, calcium silicate, and aluminosilicate; and others such as kaolin, talc, and diatomaceous earth. Specific examples of resin particles include resin particles composed of resin components such as polymethyl methacrylate (PMMA), polystyrene, methyl methacrylate-styrene copolymer, polyester, polyamide, polytetrafluoroethylene, epoxy resin, urea resin, and phenolic resin. The resin particles may be crosslinked or non-crosslinked.

[0106] From a cost and other perspective, the particles may also be inorganic compound-based antiblocking agents. The particles may also be resin particle-based antiblocking agents. For example, when storing a barrier film in roll form, in which one surface resin layer contains a resin particle-based antiblocking agent and the other surface resin layer has a vapor-deposited film, such a configuration can reduce the possibility of the particles damaging the vapor-deposited film. This is because resin particle-based antiblocking agents are usually less rough and softer than inorganic compound-based antiblocking agents.

[0107] The average particle diameter is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, preferably 6 μm or less, more preferably 5.5 μm or less, even more preferably 5 μm or less, for example, 0.5 μm or more and 6 μm or less. The average particle diameter refers to the average value (arithmetic mean diameter) of particle diameters measured for 100 randomly selected non-aggregated particles by observing the cross-section in the thickness direction of each layer with a scanning electron microscope (SEM).

[0108] When the first surface resin layer contains particles, the particle content is preferably 100 ppm or more, more preferably 500 ppm or more, even more preferably 1,000 ppm or more, preferably 10,000 ppm or less, more preferably 8,000 ppm or less, even more preferably 5,000 ppm or less, based on the mass of the first surface resin layer, for example, 100 ppm or more and 10,000 ppm or less.

[0109] In the stretched film (Y), when the first surface resin layer contains particles, the ratio of the average particle diameter to the thickness of the first surface resin layer (average particle diameter / thickness) is preferably 0.5 or more and 5.0 or less, more preferably 0.8 or more and 4.0 or less, and even more preferably 1.0 or more and 3.5 or less.

[0110] The thickness of the first surface resin layer in the stretched film (Y) is preferably 0.3 μm or more, more preferably 0.5 μm or more, even more preferably 0.8 μm or more, preferably 15 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, and particularly preferably 3 μm or less, for example, 0.3 μm or more and 15 μm or less. If the first surface resin layer has protrusions caused by particles, it is preferable that the thickness of each layer be measured in a region where no protrusions caused by the particles are formed.

[0111] The thickness of the first surface resin layer is preferably 1% or more, more preferably 2% or more, even more preferably 4% or more, preferably 20% or less, more preferably 15% or less, even more preferably 10% or less, and particularly preferably 8% or less, for example, 1% to 20% or less, relative to the thickness of the stretched film (Y).

[0112] The ratio of the thickness of the second surface resin layer to the thickness of the first surface resin layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of maintaining the symmetry of the stretched film (Y) and suppressing the occurrence of curl.

[0113] The stretched film (Y)α comprises, in this order, a first polyolefin layer as a first surface resin layer, a second polyolefin layer, a third polyolefin layer, an adhesive resin layer, and a surface resin layer (G) as a second surface resin layer.

[0114] The stretched film (Y)β comprises, in this order, a first polyolefin layer as a first surface resin layer, a second polyolefin layer, a third polyolefin layer, a fourth polyolefin layer, and a surface resin layer (AH) as a second surface resin layer.

[0115] The thickness of the second polyolefin layer and adhesive resin layer of stretched film (Y)α, and the thickness of the second and fourth polyolefin layers of stretched film (Y)β are, independently, preferably 0.5 μm or more, more preferably 0.8 μm or more, even more preferably 1 μm or more, preferably 15 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, for example, 0.5 μm or more and 15 μm or less.

[0116] The thickness of the second polyolefin layer and adhesive resin layer of stretched film (Y)α, and the thickness of the second and fourth polyolefin layers of stretched film (Y)β are, independently of each other, preferably 2% or more, more preferably 4% or more, even more preferably 6% or more, preferably 25% or less, more preferably 20% or less, even more preferably 15% or less, and particularly preferably 10% or less, for example, 2% to 25% or less, relative to the thickness of stretched film (Y).

[0117] In stretched films (Y)α and β, the thickness of the third polyolefin layer is preferably 4 μm or more, more preferably 6 μm or more, even more preferably 8 μm or more, preferably 60 μm or less, more preferably 40 μm or less, and even more preferably 20 μm or less, for example, 4 μm or more and 60 μm or less.

[0118] In stretched films (Y)α and β, the thickness of the third polyolefin layer is preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, preferably 90% or less, more preferably 85% or less, even more preferably 80% or less, for example, 40% to 90% or less, relative to the thickness of the stretched film (Y).

[0119] In stretched films (Y)α and β, the ratio of the thickness of the surface resin layer (G) or (AH) to the thickness of the first polyolefin layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of maintaining the symmetry of the stretched film (Y) and suppressing the occurrence of curl.

[0120] In the stretched film (Y)α, the ratio of the thickness of the second polyolefin layer to the thickness of the adhesive resin layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of maintaining the symmetry of the stretched film (Y) and suppressing the occurrence of curl.

[0121] In the stretched film (Y)β, the ratio of the thickness of the second polyolefin layer to the thickness of the fourth polyolefin layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of maintaining the symmetry of the stretched film (Y) and suppressing the occurrence of curl.

[0122] (Polyethylene layer) The polyethylene layer contains polyethylene as its main component. As polyethylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene are preferred. From the viewpoint of the strength and heat resistance of the stretched film (Y), high-density polyethylene and medium-density polyethylene are preferred. From the viewpoint of the film-forming properties and processability of the stretched film (Y), linear low-density polyethylene and medium-density polyethylene are preferred.

[0123] The melting point (Tm) of polyethylene in the polyethylene layer is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, particularly preferably 115°C or higher, and preferably 140°C or lower, for example, 100°C or higher and 140°C or lower, from the viewpoint of the strength and heat resistance of the stretched film (Y).

[0124] In one embodiment, at least one polyethylene layer in the film before stretching is a polyethylene layer (1) containing at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, or a layer containing polyethylene as the main component, wherein the polyethylene contained in the layer is 0.930 g / cm³. 3 Super 0.960g / cm 3 The polyethylene layer (2) has the following density:

[0125] The polyethylene layer (1) contains at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, and preferably contains high-density polyethylene. Therefore, the stretched film (Y) of the film having the polyethylene layer (1) has, for example, high heat resistance, specifically, excellent resistance to drying during printing and heating during heat sealing, and excellent resistance to vapor deposition when vapor deposition is performed on the film. In addition, the polyethylene layer (1) has, for example, high rigidity, which allows the film transport speed to be increased when vapor deposition is performed on the film, and therefore productivity can be increased.

[0126] Examples of high-density polyethylene include ethylene homopolymers and ethylene-α-olefin copolymers. Examples of α-olefins include the above-mentioned α-olefins having 3 to 20 carbon atoms, with α-olefins having 3 to 8 carbon atoms being preferred, and α-olefins having 4 to 8 carbon atoms being more preferred. Examples of ethylene-α-olefin copolymers include ethylene-1-butene copolymer (C4-HDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymer (C6-HDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymer (C8-HDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomer is not limited to the above-mentioned comonomers, and further comonomers may be used. For example, high-density polyethylene produced using a metallocene catalyst is preferred.

[0127] Examples of medium-density polyethylene include ethylene homopolymers and ethylene-α-olefin copolymers. Examples of α-olefins include the above-mentioned α-olefins having 3 to 20 carbon atoms, with α-olefins having 3 to 8 carbon atoms being preferred, and α-olefins having 4 to 8 carbon atoms being more preferred. Examples of ethylene-α-olefin copolymers include ethylene-1-butene copolymer (C4-MDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymer (C6-MDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymer (C8-MDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomer is not limited to the above-mentioned comonomers, and further comonomers may be used. For example, medium-density polyethylene produced using a metallocene catalyst is preferred.

[0128] As high-density polyethylene and medium-density polyethylene, the above-mentioned ethylene-α-olefin copolymer is preferred, respectively. Films containing such high-density polyethylene and / or medium-density polyethylene exhibit excellent biaxial stretchability, particularly in the width direction. This is presumed to be because the side chains derived from α-olefin suppress tearing of the film during stretching. As the above-mentioned ethylene-α-olefin copolymer, polyethylene obtained by polymerizing ethylene and a small amount of α-olefin by polymerization using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst is preferred, and polyethylene produced using a metallocene catalyst is more preferred.

[0129] The density of high-density polyethylene is preferably 0.945 g / cm³. 3 exceeding 0.960 g / cm³ 3 The following applies: The density of medium-density polyethylene is preferably 0.930 g / cm³. 3 Exceeding 0.945 g / cm³ 3The density can be adjusted, for example, by the amount of constituent units derived from α-olefin, which is a comonomer in the ethylene-α-olefin copolymer.

[0130] The polyethylene layer (1) may, for example, contain high-density polyethylene as its main component, contain medium-density polyethylene as its main component, or contain a mixture of high-density polyethylene and medium-density polyethylene as its main component. The polyethylene layer (1) may, for example, contain a mixture of high-density polyethylene and other polyethylenes as its main component, a mixture of medium-density polyethylene and other polyethylenes as its main component, or a mixture of high-density polyethylene, medium-density polyethylene and other polyethylenes as its main component. The statement that the main component is the above mixture means that the content of the above mixture in the polyethylene layer (1) is more than 50% by mass. The above content is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. The high-density polyethylene mentioned above may be, for example, a homopolymer of ethylene, an ethylene-α-olefin copolymer, or a mixture thereof. The medium-density polyethylene mentioned above may be, for example, a homopolymer of ethylene, an ethylene-α-olefin copolymer, or a mixture thereof. Other polyethylenes mentioned above include, for example, at least one selected from the group consisting of linear low-density polyethylene and high-pressure low-density polyethylene, which may be linear low-density polyethylene, high-pressure low-density polyethylene, or a mixture of linear low-density polyethylene and high-pressure low-density polyethylene.

[0131] The total content of high-density polyethylene and medium-density polyethylene in the polyethylene layer (1) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and may also be 30% by mass or more, 35% by mass or more, or 40% by mass or more, from the viewpoint of heat resistance. The total content of high-density polyethylene and medium-density polyethylene in the polyethylene layer (1) is 100% by mass or less, preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and may also be 70% by mass or less, 65% by mass or less, or 60% by mass or less. The total content of high-density polyethylene and medium-density polyethylene in the polyethylene layer (1) is, for example, 10% by mass or more and 100% by mass or less, preferably 20% by mass or more and 60% by mass or less.

[0132] When the polyethylene layer (1) is the first surface resin layer of the film before stretching, a small total content ratio tends to improve adhesion between the first surface resin layer and the printed layer, etc., through the surface treatment described above. This is presumed to be because, for example, high-density polyethylene has high crystallinity, and surface treatments such as corona treatment may not adequately introduce polar groups into the polyethylene layer. However, when the total content ratio is small, surface treatments such as corona treatment can adequately introduce polar groups into the polyethylene layer. Furthermore, when the polyethylene layer (1) is the first surface resin layer of the film before stretching, a small total content ratio tends to result in superior appearance, surface smoothness, and transparency of the stretched film (Y).

[0133] From the viewpoint of biaxial tractability, the polyethylene layer (1) preferably contains linear low-density polyethylene in addition to at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, and more preferably contains linear low-density polyethylene in addition to high-density polyethylene.

[0134] Examples of linear low-density polyethylene include ethylene-α-olefin copolymers. Examples of α-olefins include the α-olefins with 3 to 20 carbon atoms mentioned above, with α-olefins with 3 to 8 carbon atoms being preferred, and α-olefins with 4 to 8 carbon atoms being 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. The density of the linear low-density polyethylene is preferably 0.900 g / cm³. 3 More than 0.930g / cm 3 The following applies:

[0135] The content of linear low-density polyethylene in the polyethylene layer (1) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and may also be 30% by mass or more, 35% by mass or more, or 40% by mass or more, from the viewpoint of biaxial stretchability. From the viewpoint of heat resistance, the content of linear low-density polyethylene in the polyethylene layer (1) is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, and may also be 70% by mass or less, 65% by mass or less, or 60% by mass or less. The content of linear low-density polyethylene in the polyethylene layer (1) is, for example, 10% by mass or more and 90% by mass or less, preferably 40% by mass or more and 80% by mass or less.

[0136] The polyethylene layer (1) contains polyethylene as its main component. The polyethylene content in the polyethylene layer (1) 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.

[0137] The polyethylene layer (1) may contain polyethylene other than high-density polyethylene, medium-density polyethylene, and linear low-density polyethylene, or resin materials other than polyethylene. Examples of resin materials other than polyethylene include polyolefins other than polyethylene, polyesters, polyamides, (meth)acrylic resins, vinyl resins, cellulose resins, and ionomer resins.

[0138] The polyethylene layer (1) may contain the above-mentioned additives.

[0139] The polyethylene layer (2) contains polyethylene as its main component, and the polyethylene is present in a concentration of 0.930 g / cm³. 3 Super 0.960g / cm 3 The following densities are observed. The density of the polyethylene in the polyethylene layer (2) is preferably 0.931 g / cm³. 3 More than 0.955g / cm 3 More preferably, 0.931 g / cm³ 3 More than 0.950g / cm 3 The following applies:

[0140] If the polyethylene layer (2) contains two or more types of polyethylene with different densities, the density of the polyethylene refers to the density of the mixture of the two or more types of polyethylene. This density is measured for polyethylene sampled from the layer in accordance with JIS K7112-2:2023 (density gradient pipe method, 23°C). If this measurement is difficult, the average density D is calculated according to the following formula. av This may be the density of the polyethylene constituting the layer.

[0141] D av = ΣW i ×D i In the formula, Σ represents W from 1 to n (where n types of polyethylene exist) for i. i ×D i This means taking the sum of n, where n is an integer greater than or equal to 2, and W i This indicates the mass fraction of the i-th polyethylene, and D iThe density of the i-th polyethylene (g / cm³) 3 ) indicates.

[0142] The density of the polyethylene layer (2) can be adjusted, for example, based on the composition described for the polyethylene layer (1) above. That is, the polyethylene layer (2) can have the composition described for the polyethylene layer (1).

[0143] The polyethylene layer (2) may contain resin materials other than polyethylene. The polyethylene layer (2) may contain the above-mentioned additives.

[0144] The first surface resin layer in the stretched film (Y) may be a polyethylene layer.

[0145] In the stretched film (Y) of each of the above embodiments, any adjacent layers selected from the polyethylene intermediate layer, the first surface resin layer containing polyethylene as the main component, and the surface resin layer (AH) containing polyethylene and adhesive resin are referred to as layer (i) and layer (ii). The absolute difference between the density of polyethylene constituting layer (i) and the density of polyethylene constituting layer (ii) is preferably 0.030 g / cm³ in both cases. 3 More preferably, 0.025 g / cm³ 3 More preferably, 0.020 g / cm³ 3 The following is particularly preferred: 0.010 g / cm³ 3 The following applies: Such films exhibit excellent interlayer adhesion and, for example, excellent drop resistance.

[0146] In one embodiment of the stretched film (Y), the density of polyethylene in the polyethylene intermediate layer is higher than that of the first surface resin layer, and optionally, the density of polyethylene in the second surface resin layer (surface resin layer (AH)) is lower than that of the polyethylene intermediate layer. Such a stretched film (Y) tends to have an excellent balance of surface smoothness, transparency, printability, vapor deposition adhesion, and heat resistance. If the polyethylene intermediate layer is thicker than the first surface resin layer, high heat resistance can be obtained due to the polyethylene intermediate layer. The density difference of polyethylene between the surface resin layer and the polyethylene intermediate layer is, for example, 0.003 g / cm³. 3 That's fine too. The total proportion of high-density polyethylene and medium-density polyethylene will be referred to as "Proportion A" below. This may consist of high-density polyethylene alone, medium-density polyethylene alone, or a mixture of high-density polyethylene and medium-density polyethylene. In one embodiment of the film before stretching, the content A in the polyethylene intermediate layer is greater than the content A in the first surface resin layer, and optionally, the content A in the second surface resin layer (surface resin layer (AH)) is smaller than the content A in the polyethylene intermediate layer. The stretched film (Y) of such a film tends to have an excellent balance of surface smoothness, transparency, printability, vapor deposition adhesion, and heat resistance. The difference in content A between the surface resin layer and the polyethylene intermediate layer may be, for example, 10% by mass or more, 50% by mass or less, 40% by mass or less, or 30% by mass or less.

[0147] In one embodiment of the stretched film (Y), the density of polyethylene in the polyethylene intermediate layer is lower than the density of polyethylene in the first surface resin layer, and optionally, the density of polyethylene in the second surface resin layer (surface resin layer (AH)) is higher than the density of polyethylene in the polyethylene intermediate layer. Such a stretched film (Y) tends to have an excellent balance between biaxial stretchability and heat resistance. If the polyethylene intermediate layer is thicker than the first surface resin layer, high biaxial stretchability can be obtained by the polyethylene intermediate layer. The density difference of polyethylene between the surface resin layer and the polyethylene intermediate layer is, for example, 0.003 g / cm³. 3 That's fine too. In one embodiment of the film before stretching, the content A in the polyethylene intermediate layer is smaller than the content A in the first surface resin layer, and optionally, the content A in the second surface resin layer (surface resin layer (AH)) is larger than the content A in the polyethylene intermediate layer. Such films tend to have an excellent balance between biaxial stretchability and heat resistance. The difference in content A between the surface resin layer and the polyethylene intermediate layer may be, for example, 10% by mass or more, 50% by mass or less, 40% by mass or less, or 30% by mass or less.

[0148] In one embodiment of the stretched film (Y), the densities of polyethylene in the first surface resin layer, the polyethylene intermediate layer, and optionally the second surface resin layer (surface resin layer (AH)) are approximately equal. For example, among the first surface resin layer, the polyethylene intermediate layer, and optionally the second surface resin layer, the difference in density between the layer with the highest polyethylene density and the layer with the lowest polyethylene density is 0.003 g / cm³. 3 It is less than. In a film of one embodiment before stretching, the content ratio A in the first surface resin layer, the polyethylene intermediate layer, and optionally the second surface resin layer (surface resin layer (AH)) is approximately the same. For example, among the first surface resin layer, the polyethylene intermediate layer, and optionally the second surface resin layer, the difference in content ratio A between the layer with the highest content ratio A and the layer with the lowest content ratio A is less than 10% by mass.

[0149] Furthermore, if each of the above layers contains two or more types of polyethylene with different densities, the density of the polyethylene refers to the density of the mixture of the two or more types of polyethylene. The method for measuring and calculating the density is as described above.

[0150] (Polypropylene layer) The polypropylene layer contains polypropylene as its main component. Examples of polypropylene include homopolypropylene, random polypropylene, and block polypropylene. Among these, homopolypropylene is preferred from the viewpoint of the heat resistance of the stretched film (Y).

[0151] The polypropylene may be isotactic polypropylene, syndiotactic polypropylene, or atactic polypropylene. From the viewpoint of the heat resistance of the stretched film (Y), isotactic polypropylene and syndiotactic polypropylene are preferred as the polypropylene, and isotactic polypropylene is more preferred.

[0152] The melting point (Tm) of polypropylene in the polypropylene layer is preferably 130°C or higher, more preferably 140°C or higher, even more preferably 150°C or higher, even more preferably 160°C or higher, particularly preferably 165°C or higher, and preferably 175°C or lower, for example, 130°C or higher and 175°C or lower, from the viewpoint of the strength and heat resistance of the stretched film (Y).

[0153] The first surface resin layer in the stretched film (Y) may be a polypropylene layer. The polypropylene layer as the first surface resin layer may contain homopolypropylene and random polypropylene, for example, from the viewpoint of adhesion with other layers provided on the first surface resin layer in the laminate described later. For example, in the first surface resin layer, it is preferable that the content of homopolypropylene is 50% by mass or more and 95% by mass or less, and the content of random polypropylene is 5% by mass or more and 50% by mass or less, more preferably that the content of homopolypropylene is 60% by mass or more and 90% by mass or less, and the content of random polypropylene is 10% by mass or more and 40% by mass or less, and even more preferably that the content of homopolypropylene is 70% by mass or more and 85% by mass or less, and the content of random polypropylene is 15% by mass or more and 30% by mass or less.

[0154] ≪Surface resin layer (G)≫ The surface resin layer (G) contains a gas barrier resin as its main component. The stretched film (1) equipped with the surface resin layer (G) has superior gas barrier properties (especially oxygen barrier properties), heat resistance, and rigidity compared to conventional polyolefin stretched films. The surface resin layer (G) tends to have excellent surface smoothness. The vapor-deposited film provided on the surface of the surface resin layer (G) tends to have excellent adhesion to the surface resin layer (G) and exhibit good gas barrier properties.

[0155] Gas barrier resins are resins that have the function of suppressing the permeation of gases. Examples of gas barrier resins include ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyamides, polyvinylidene chloride, polyesters, polyether polyols, polyester polyols, polyurethanes, polyacrylonitriles, and (meth)acrylic resins. Among these, ethylene-vinyl alcohol copolymers, polyvinyl alcohols, and polyamides are preferred from the viewpoint of gas barrier properties (especially oxygen barrier properties), heat resistance, and rigidity, ethylene-vinyl alcohol copolymers and polyamides are more preferred, and ethylene-vinyl alcohol copolymers are even more preferred from the viewpoint of gas barrier properties.

[0156] Ethylene-vinyl alcohol copolymers (EVOH) can be obtained, for example, by copolymerizing ethylene with a vinyl ester monomer and then saponifying the copolymer. 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. EVOH may be modified by known methods, such as urethaneization, acetalization, cyanoethylation, or oxyalkyleneization.

[0157] Vinyl acetate is generally used as the vinyl ester monomer, but other vinyl ester monomers may also be used. Examples of other vinyl ester monomers include 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, as well as aromatic vinyl esters such as vinyl benzoate.

[0158] In EVOH, the ethylene content is preferably 20 mol% or more, more preferably 25 mol% or more, of the total repeating constituent units, from the viewpoint of processability of the stretched film. From the viewpoint of excellent surface smoothness, stretchability, and especially biaxial stretchability, it is even more preferably 30 mol% or more, even more preferably 35 mol% or more, and particularly preferably 40 mol% or more or 45 mol% or more. In EVOH, the ethylene content is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less, of the total repeating constituent units, from the viewpoint of heat resistance of the stretched film, heat resistance of the barrier layer, oxygen barrier properties, and water vapor barrier properties. For example, the ethylene content is 20 mol% or more and 60 mol% or less. The ethylene content is measured by NMR spectroscopy.

[0159] The average degree of saponification in EVOH is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. The average degree of saponification is measured in accordance with JIS K6726:1994 (provided that EVOH is a solution uniformly dissolved in water / methanol solvent).

[0160] In one embodiment, 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, preferably 200°C or lower, more preferably 195°C or lower, even more preferably 190°C or lower, for example, 140°C to 200°C, from the viewpoint of heat resistance. Such a Tm is preferred, for example, in the case of a stretched film (X). In one embodiment, the melting point (Tm) of EVOH is preferably 130°C or higher, more preferably 135°C or higher, even more preferably 140°C or higher, preferably 200°C or lower, more preferably 190°C or lower, even more preferably 180°C or lower, even more preferably 170°C or lower, and particularly preferably 165°C or lower, for example, 130°C to 200°C. Such a Tm is preferred, for example, in the case of a stretched film (Y).

[0161] In one embodiment, 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, 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, from the viewpoint of film-forming ability and processability. Such an MFR is preferred, for example, in the case of a stretched film (X). In one embodiment, the MFR of EVOH is preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more, even more preferably 1.5 g / 10 min or more, preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 10 g / 10 min or less, for example, 0.1 g / 10 min or more and 50 g / 10 min or less, from the viewpoint of film-forming ability and processability. Such an MFR is preferred, for example, in the case of a stretched film (Y). 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 EVOH.

[0162] The average degree of saponification in 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 degree of saponification is measured in accordance with JIS K6726:1994.

[0163] 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.

[0164] Examples of aliphatic polyamides include aliphatic homopolyamides and aliphatic copolymer polyamides. In the following examples, polyamide will also be referred to as "PA".

[0165] Aliphatic homopolyamides include, specifically, polycaprolactam or poly(6-aminocaproic acid) (PA6), polyenanthic acid or poly(7-aminoenanthic acid) (PA7), polyundecanelactam or poly(11-aminoundecanoic acid) (PA11), polylauryllactam or poly(12-aminolauric acid) (PA12), polyhexamethylene adipamide (PA66), polytetramethylene dodecamide (PA412), polypentamethylene azeramide (PA59), polypentamethylene sebaamide (PA510), polypentamethylene dodecamide (PA512), polyhexamethylene azeramide (PA69), and polyhexamethylene seba Examples include Camide (PA610), polyhexamethylene dodecamide (PA612), polynonameethylene adipamide (PA96), polynonameethylene azeramide (PA99), polynonameethylene sevacamide (PA910), polynonameethylene dodecamide (PA912), polydecamethylene azeramide (PA106), polydecamethylene azeramide (PA109), polydecamethylene decadamide (PA1010), polydecamethylene dodecamide (PA1012), polidodecamethylene adipamide (PA126), polidodecamethylene azeramide (PA129), polidodecamethylene sevacamide (PA1210), and polidodecamethylene dodecamide (PA1212).

[0166] Specifically, 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), and caprolactam / amino Examples include undecanoic acid copolymer (PA6 / 11), caprolactam / lauryl lactam copolymer (PA6 / 12), caprolactam / hexamethylenediaminoadipic acid / lauryl lactam copolymer (PA6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymer (PA6 / 66 / 610), and caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymer (PA6 / 66 / 612).

[0167] As the aliphatic polyamide, crystalline aliphatic polyamide is preferred. Examples of crystalline aliphatic polyamides 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, 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, and particularly preferably 230°C or lower, for example, 170°C to 300°C.

[0168] Examples of aromatic polyamides include semi-aromatic polyamides and fully aromatic polyamides, with semi-aromatic polyamides being preferred. A semi-aromatic polyamide is a polyamide having structural units derived from aromatic diamines and structural units derived from aliphatic dicarboxylic acids, or a polyamide 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.

[0169] Examples of semi-aromatic polyamides include polyhexamethylene terephthalamide (PA6T), polyhexamethylene isophthalamide (PA6I), polynonameethylene 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), and 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.

[0170] In one embodiment, crystalline semi-aromatic polyamides are preferred as semi-aromatic polyamides. The melting point (Tm) of crystalline semi-aromatic polyamides is preferably 190°C or higher, more preferably 200°C or higher, even more preferably 210°C or higher, preferably 310°C or lower, more preferably 280°C or lower, and even more preferably 250°C or lower, for example, 190°C to 310°C. Specifically, PA6T, PA9T, and PAMXD6 are preferred as crystalline semi-aromatic polyamides.

[0171] The glass transition temperature (Tg) of crystalline semi-aromatic polyamide is preferably 50°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher, preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower, for example, 50°C to 140°C. The above Tg may also be, for example, less than 110°C, less than 100°C, or less than 90°C. In this specification, Tg is the intermediate glass transition temperature obtained by differential scanning calorimetry (DSC) under a heating rate of 10°C / min in accordance with JIS K7121:2012 (using a test specimen conditioned according to 3.(3)).

[0172] As a semi-aromatic polyamide, amorphous semi-aromatic polyamides are preferred in one embodiment because they can form a surface resin layer with excellent surface smoothness and transparency, and can exhibit high gas barrier properties when a vapor-deposited film is formed on the surface resin layer. Specifically, PA6I / 6T is preferred as the amorphous semi-aromatic polyamide.

[0173] Amorphous polyamide refers to a polyamide that does not have a distinct crystalline melting peak. Specifically, it refers to a polyamide that either has no crystalline melting peak or has a crystalline melting peak with a crystalline melting enthalpy ΔHm of 5 J / g or less, preferably 3 J / g or less, and more preferably 1 J / g or less. The crystalline melting enthalpy is obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012 and JIS K7122:2012.

[0174] As amorphous semi-aromatic polyamides, semi-aromatic polyamides having two or more constituent units derived from aromatic dicarboxylic acids are preferred, and polyamides having constituent units derived from isophthalic acid and terephthalic acid as dicarboxylic acid components, and constituent units derived from aliphatic diamines as diamine components (hereinafter also referred to as "polyamide (a)") are more preferred.

[0175] In polyamide (a), the proportion of isophthalic acid-derived constituent units is preferably 40 mol% to 98 mol%, more preferably 50 mol% to 80 mol%, of 100 mol% of dicarboxylic acid-derived constituent units, and the proportion of terephthalic acid-derived constituent units is preferably 2 mol% to 60 mol%, more preferably 20 mol% to 50 mol%. The above proportions are measured by NMR spectroscopy.

[0176] In polyamide (a), the total proportion of constituent units derived from isophthalic acid and terephthalic acid in 100 mol% of constituent units derived from dicarboxylic acid is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, 95 mol% or more, or 98 mol% or more. Polyamide (a) may optionally contain constituent units derived from dicarboxylic acids other than isophthalic acid and terephthalic acid (e.g., adipic acid).

[0177] Polyamide (a) preferably has structural units derived from hexamethylenediamine as a diamine component. In polyamide (a), the proportion of structural units derived from hexamethylenediamine in 100 mol% of diamine-derived structural units is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, 95 mol% or more, or 98 mol% or more. Polyamide (a) may also have structural units derived from diamines other than hexamethylenediamine as needed. The polyamide (a) is preferably PA6I / 6T.

[0178] The glass transition temperature (Tg) of amorphous semi-aromatic polyamide is preferably 90°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, preferably 180°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower, for example, between 90°C and 180°C. Amorphous semi-aromatic polyamide with a Tg above the above lower limit exhibits excellent heat resistance. Therefore, by using such amorphous semi-aromatic polyamide, a surface resin layer with high heat resistance can be formed.

[0179] The melt volume rate (MVR) of the semi-aromatic polyamide is preferably 5 cm². 3 / 10 minutes or more, more preferably 10 cm 3 / 10 minutes or more, preferably 200 cm 3 / 10 minutes or less, or 100cm 3 Less than 10 minutes, for example, 5cm 3 / 200cm for more than 10 minutes 3 The time is less than 10 minutes. MVR is measured in accordance with JIS K7210-1:2014 at a temperature of 275°C and a load of 5.00 kg.

[0180] The relative viscosity of the polyamide is preferably 1.5 or higher, more preferably 2.0 or higher, even more preferably 2.5 or higher, preferably 5.0 or lower, more preferably 4.5 or lower, even more preferably 4.0 or lower, for example, between 1.5 and 5.0. The relative viscosity of the polyamide is measured in accordance with JIS K6920-2:2009, by dissolving 1 g of polyamide in 100 mL of 96% concentrated sulfuric acid and measuring at 25°C.

[0181] In one embodiment, the polyamide MFR 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, 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, from the viewpoint of film-forming ability and processability. Such an MFR is preferred, for example, in the case of a stretched film (X). In one embodiment, the polyamide MFR 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, even more preferably 1 g / 10 min or more, particularly preferably 1.5 g / 10 min or more, preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 10 g / 10 min or less, for example, 0.1 g / 10 min or more and 50 g / 10 min or less, from the viewpoint of film-forming ability and processability. Such an MFR is preferred, for example, in the case of a stretched film (Y). The MFR of polyamide is measured by Method A in accordance with JIS K7210-1:2014, under conditions 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.

[0182] The surface resin layer (G) may contain polyamide as its main component. The surface resin layer (G) may contain aliphatic polyamide as its main component. Such a stretched film (1) has excellent processability and manufacturing cost, for example. For example, the aliphatic polyamide content 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.

[0183] The surface resin layer (G) may contain aromatic polyamide as the main component. Such a stretched film (1) has excellent properties, for example, 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.

[0184] The surface resin layer (G) may contain aliphatic polyamide and aromatic polyamide. Aliphatic polyamide tends to have superior processability. Aromatic polyamide tends to have superior 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 manufacturing cost of the stretched film, the content of 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 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.

[0185] The surface resin layer (G) may mainly contain amorphous semi-aromatic polyamide having a high glass transition temperature (e.g., 90°C or higher). Such a stretched film (1) has excellent heat resistance, for example. 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.

[0186] The surface resin layer (G) may contain crystalline semi-aromatic polyamide and amorphous semi-aromatic polyamide from the viewpoint of balancing heat resistance and processability. For example, in the surface resin layer (G), the content of 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 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.

[0187] 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, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more or 95% by mass or more, from the viewpoint of the above-mentioned physical properties such as gas barrier properties.

[0188] The surface resin layer (G) may contain resin materials other than the above-mentioned components. The surface resin layer (G) may contain the above-mentioned additives.

[0189] The thickness of the surface resin layer (G) in the stretched film (X) 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 aforementioned 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. The thickness of the surface resin layer (G) in the stretched film (Y) is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 0.8 μm or more, from the viewpoint of the aforementioned physical properties such as gas barrier properties. The thickness of the surface resin layer (G) is preferably 15 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, and particularly preferably 3 μm or less, from the viewpoint of recyclability. The thickness of the surface resin layer (G) is, for example, 0.3 μm or more and 15 μm or less.

[0190] The thickness of the surface resin layer (G) is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, for example, 1% to 30% or less, relative to the thickness of the stretched film (X). The thickness of the surface resin layer (G) is preferably 1% or more, more preferably 2% or more, even more preferably 4% or more, preferably 20% or less, more preferably 15% or less, even more preferably 10% or less, and particularly preferably 8% or less, for example, 1% to 20% or less, relative to the thickness of the stretched film (Y).

[0191] ≪Surface resin layer (AH)≫ The surface resin layer (AH) contains polyolefin and an adhesive resin. In the case of a stretched film (X), the surface resin layer (AH) contains polyethylene and an adhesive resin. A vapor-deposited film provided on the surface of the surface resin layer (AH) tends to exhibit excellent adhesion to the surface resin layer (AH) and good gas barrier properties.

[0192] Examples of polyolefins include polyethylene, polypropylene, polybutene, and polymethylpentene. Among these, polyethylene and polypropylene are preferred.

[0193] As polyethylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene are preferred, with linear low-density polyethylene being more preferred from the viewpoint of surface smoothness of the stretched film and adhesion between the surface resin layer (AH) and the vapor-deposited film. 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.

[0194] The melting point (Tm) of polyethylene 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, particularly preferably 115°C or higher, and preferably 140°C or lower, for example, 100°C or higher and 140°C or lower, from the viewpoint of the strength and heat resistance of the stretched film and the adhesion between the surface resin layer (AH) and the vapor-deposited film.

[0195] Examples of polypropylene include homopolypropylene, random polypropylene, and block polypropylene. Among these, random polypropylene and homopolypropylene are preferred, with random polypropylene being more preferred, from the viewpoint of surface smoothness of the stretched film, adhesion between the surface resin layer (AH) and the vapor-deposited film, and heat resistance of the stretched film. If the content of random polypropylene in the stretched film (1) is high, the heat resistance may not be sufficient. In such cases, the main component of the polypropylene intermediate layer described above may be made homopolypropylene.

[0196] The melting point (Tm) of polypropylene in the surface resin layer (AH) is preferably 120°C or higher, more preferably 125°C or higher, even more preferably 130°C or higher, preferably 175°C or lower, more preferably 170°C or lower, even more preferably 165°C or lower, even more preferably 160°C or lower, and particularly preferably 155°C or lower or 150°C or lower, for example, 120°C or higher and 175°C or lower.

[0197] Examples of the adhesive resin include acid-modified resins, silicone resins, epoxy resins and phenolic resins, with acid-modified resins being preferred. Examples of the acid-modified resin include acid-modified polyolefins and acid-modified vinyl resins. Among these, from the viewpoints of recyclability and adhesiveness, acid-modified polyolefins are preferred, and acid-modified polyethylene and acid-modified polypropylene are more preferred. In the case of a polyethylene-based stretched film, acid-modified polyethylene is more preferred, and acid-modified linear low-density polyethylene is even more preferred. The surface resin layer (AH) containing acid-modified linear low-density polyethylene tends to be more excellent in adhesiveness to a deposited film. In the case of a polypropylene-based stretched film, acid-modified polypropylene is more preferred; from the viewpoints of heat resistance and adhesiveness, acid-modified random polypropylene and acid-modified homopolypropylene are even more preferred, and acid-modified random polypropylene is particularly preferred. The surface resin layer (AH) containing acid-modified random polypropylene tends to be more excellent in adhesiveness to a deposited film.

[0198] In one embodiment of the stretched film (Y) according to the second aspect, the polyolefin in the surface resin layer (AH) contains polyethylene, the adhesive resin contains acid-modified polyethylene, and the polyolefin layer is a polyethylene layer.

[0199] In one embodiment of the stretched film (Y) according to the second aspect, the polyolefin in the surface resin layer (AH) contains polypropylene, the adhesive resin contains acid-modified polypropylene, and the polyolefin layer is a polypropylene layer. In one embodiment of the stretched film (Y) according to the second aspect, the polyolefin in the surface resin layer (AH) contains random polypropylene, the adhesive resin contains acid-modified random polypropylene, and the polyolefin layer contains homopolypropylene as a main component.

[0200] Examples of the acid-modified polyolefin include modified products of polyolefins (e.g., polyethylene and polypropylene) modified with an acid-modifying component, and particularly include graft-modified products of polyolefin modified with an acid-modifying component. Examples of the acid-modifying component include unsaturated carboxylic acids such as maleic acid, fumaric acid, acrylic acid, methacrylic acid, itaconic acid, citraconic acid, tetrahydrophthalic acid and methyltetrahydrophthalic acid, or acid anhydrides, esters or metal salts thereof. Preferred examples of the acid-modified polyolefin include maleic acid-modified polyolefin and maleic anhydride-modified polyolefin; more preferred examples include maleic acid-modified polyethylene, maleic anhydride-modified polyethylene, maleic acid-modified polypropylene and maleic anhydride-modified polypropylene; and in the case of a polyethylene-based stretched film, maleic acid-modified polyethylene and maleic anhydride-modified polyethylene are even more preferred.

[0201] From the viewpoint of adhesion between the surface resin layer (AH) and the deposited film, the content ratio of the constitutional unit derived from the acid-modifying 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 a polyolefin layer such as a polyethylene layer or a polypropylene layer, the content ratio of the constitutional unit derived from the acid-modifying 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. The aforementioned content ratio is, for example, 0.01% by mass or more and 10% by mass or less. The content ratio of the constitutional unit derived from the acid-modifying component is measured by infrared spectroscopy.

[0202] For example, in the case of a stretched film (X), from the viewpoints of film-forming properties 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 is 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. The MFR of the acid-modified polyolefin is, for example, in the case of a stretched film (Y), preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more, even more preferably 1.5 g / 10 min or more, preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 10 g / 10 min or less, for example, 0.1 g / 10 min or more and 50 g / 10 min or less, from the viewpoint of film-forming ability and processability. The MFR of acid-modified polyolefins is measured by Method A under a load of 2.16 kg, in accordance with JIS K7210-1:2014. The measurement temperature for MFR is set according to the melting point of the acid-modified polyolefin, and is 190°C for acid-modified polyethylene and 230°C for acid-modified polypropylene.

[0203] The density of acid-modified polyethylene is within the same range as that of polyethylene, as described above. The melting point (Tm) of acid-modified polyethylene is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, particularly preferably 115°C or higher, and preferably 140°C or lower, for example, 100°C to 140°C, from the viewpoint of the strength and heat resistance of the stretched film and the adhesion between the surface resin layer (AH) and the vapor-deposited film.

[0204] The density of acid-modified polypropylene is, for example, 0.88 g / cm³. 3 More than 0.92g / cm 3 The following applies. In this specification, the density of acid-modified polypropylene is measured in accordance with JIS K7112-2:2023 (density gradient pipe method, 23°C).

[0205] The melting point (Tm) of acid-modified polypropylene is preferably 120°C or higher, more preferably 125°C or higher, even more preferably 130°C or higher, preferably 175°C or lower, more preferably 170°C or lower, even more preferably 165°C or lower, even more preferably 160°C or lower, and particularly preferably 155°C or lower or 150°C or lower, for example, 120°C to 175°C.

[0206] In the surface resin layer (AH), it is preferable that the polyolefin content is 60% to 95% by mass and the adhesive resin content is 5% to 40% by mass, more preferably that the polyolefin content is 70% to 95% by mass and the adhesive resin content is 5% to 30% by mass, even more preferably that the polyolefin content is 80% to 95% by mass and the adhesive resin content is 5% to 20% by mass, and particularly preferably that the polyolefin content is 85% to 95% by mass and the adhesive resin content is 5% to 15% by mass. Surface resin layers (AH) of this type tend to have superior surface smoothness, adhesion to vapor-deposited films, and adhesion to polyolefin layers. When the adhesive resin content is below the upper limit, for example, it is possible to suppress excessive adhesion of the film to rolls, etc., during the production of stretched films. The polyolefin is, for example, polyethylene or polypropylene. In the case of stretched film (X), replace "polyolefin" with "polyethylene" above.

[0207] The following describes the case of stretched film (Y). The surface resin layer (AH) of the film before stretching may contain linear low-density polyethylene as its main component, from the viewpoint of biaxial tractability and surface smoothness. Details of linear low-density polyethylene are as described above in the explanation of the polyethylene layer (1), and will not be explained in this section.

[0208] In one embodiment, the surface resin layer (AH) in the film before stretching contains at least one polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, preferably containing high-density polyethylene. Therefore, the stretched film (Y) having such a surface resin layer has, for example, high heat resistance, specifically, excellent resistance to drying during printing and heating during heat sealing, and excellent resistance to vapor deposition when vapor deposition is performed on the film. Furthermore, the surface resin layer has, for example, high rigidity, which allows for an increase in the film transport speed when vapor deposition is performed on the film, and thus increases productivity.

[0209] Details of high-density polyethylene and medium-density polyethylene are as described above in the explanation of the polyethylene layer (1), and will not be explained further in this section. For high-density polyethylene and medium-density polyethylene, the ethylene-α-olefin copolymers described above are preferred, respectively.

[0210] In one embodiment, the content of linear low-density polyethylene in 100% by mass of polyethylene contained in the surface resin layer (AH) of the film before stretching may be 60% by mass or more, 65% by mass or more, 70% by mass or more, 100% by mass or less, 95% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, for example, 60% by mass or more and 100% by mass or less.

[0211] In one embodiment, the total content of high-density polyethylene and medium-density polyethylene in 100% by mass of polyethylene contained in the surface resin layer (AH) of the film before stretching may be 0% by mass or more, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 40% by mass or less, 35% by mass or less, 30% by mass or less, for example, 0% by mass or more and 40% by mass or less.

[0212] In one embodiment, the polyethylene contained in the surface resin layer (AH) of the film before stretching is 0.930 g / cm³. 3 Super 0.960g / cm 3 It may have the following density, preferably 0.931 g / cm³ 3 More than 0.955g / cm 3 More preferably, 0.931 g / cm³ 3 More than 0.950g / cm 3 The following applies: If the surface resin layer (AH) contains two or more types of polyethylene with different densities, the density of the polyethylene refers to the density of the mixture of the two or more types of polyethylene. The above describes the case of stretched film (Y).

[0213] The surface resin layer (AH) may contain resin materials other than the above-mentioned components. The surface resin layer (AH) may contain the above-mentioned additives.

[0214] From the viewpoint of achieving the above-mentioned effects, the thickness of the surface resin layer (AH) in the stretched film (X) 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 recyclability, 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. For example, the thickness of the surface resin layer (AH) is 0.5 μm or more and 10 μm or less. From the viewpoint of better exhibiting the above-mentioned effects, the thickness of the surface resin layer (AH) in the stretched film (Y) is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 0.8 μm or more. The thickness of the surface resin layer (AH) is preferably 15 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, and particularly preferably 3 μm or less. The thickness of the surface resin layer (AH) is, for example, 0.3 μm or more and 15 μm or less.

[0215] The thickness of the surface resin layer (AH) is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, preferably 30% or less, more preferably 25% or less, even more preferably 20% or less, for example, 1% to 30% or less, relative to the thickness of the stretched film (X). The thickness of the surface resin layer (AH) is preferably 1% or more, more preferably 2% or more, even more preferably 4% or more, preferably 20% or less, more preferably 15% or less, even more preferably 10% or less, and particularly preferably 8% or less, for example, 1% to 20% or less, relative to the thickness of the stretched film (Y).

[0216] ≪Adhesive resin layer≫ The stretched film (1) of the first embodiment may further include an adhesive resin layer between the polyolefin layer, such as a polyethylene layer or a polypropylene layer, and the surface resin layer (G). Such a stretched film (1) has excellent interlayer adhesion, for example.

[0217] The adhesive resin layer contains adhesive resin as its main component. Examples of the adhesive resin include acid-modified resins, silicone resins, epoxy resins and phenol resins, with acid-modified resins being preferred. Examples of the acid-modified resin include acid-modified polyolefins and acid-modified vinyl resins. Among these, acid-modified polyolefins are preferred, and acid-modified polyethylene and acid-modified polypropylene are more preferred. In the case of a polyethylene-based stretched film, acid-modified polyethylene is further preferred, and acid-modified linear low-density polyethylene is even more preferred, from the viewpoints of recyclability and adhesiveness to both the polyethylene layer and the surface resin layer. In the case of a polypropylene-based stretched film, acid-modified polypropylene is further preferred from the viewpoints of recyclability and adhesiveness to both the polypropylene layer and the surface resin layer; acid-modified random polypropylene and acid-modified homopolypropylene are even more preferred from the viewpoints of heat resistance and adhesiveness, and acid-modified random polypropylene is particularly preferred. Details of the acid-modified polyolefin (including its constitution and physical properties such as MFR, density and Tm) are as described in the section for the surface resin layer (AH), and description thereof is omitted here.

[0218] From the viewpoint of adhesiveness between the polyolefin layer (e.g., a polyethylene layer or a polypropylene layer) and the surface resin layer (G), the content of the constitutional 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, still more preferably 0.1% by mass or more, and is preferably 10% by mass or less, more preferably 5% by mass or less, still 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 constitutional units derived from the acid-modified component is measured by infrared spectroscopy.

[0219] The content of the adhesive resin in the adhesive resin layer is preferably 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0220] The adhesive resin layer may contain the above additives.

[0221] From the viewpoint of adhesion, the thickness of the adhesive resin layer in the stretched film (1) 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 (1) and the barrier layer, 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. For example, the thickness of the adhesive resin layer is 0.5 μm or more and 15 μm or less.

[0222] The thickness of the adhesive resin layer is preferably 1% or more, more preferably 3% or more, even more preferably 5% or more, preferably 20% or less, more preferably 18% or less, even more preferably 15% or less, for example, 2% to 20% or less, relative to the thickness of the stretched film (X). The thickness of the adhesive resin layer is preferably 2% or more, more preferably 4% or more, even more preferably 6% or more, preferably 25% or less, more preferably 20% or less, even more preferably 15% or less, and particularly preferably 10% or less, for example, 2% to 25%.

[0223] <Stretched film (2)> The stretched film (2) has a first surface and a second surface facing the first surface. The stretched film (2) is a polyolefin-based stretched film. Examples of polyolefin-based stretched films include stretched polyethylene films and stretched polypropylene films. The anchor coat layer is provided on the second surface of the stretched film (2).

[0224] Polyethylene film and its stretched film A polyethylene film comprises a layer containing polyethylene as its main component, which constitutes its second surface. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene.

[0225] The melt flow rate (MFR) of 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, 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, from the viewpoint of film-forming and processability by the inflation method. In the first embodiment described later, such an MFR range is preferred. The melt flow rate (MFR) of polyethylene is preferably 0.1 g / 10 min or more, more preferably 1 g / 10 min or more, even more preferably 1.5 g / 10 min or more, preferably 50 g / 10 min or less, more preferably 30 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 50 g / 10 min or less, from the viewpoint of film-forming and processability by the T die-casting method. In the second embodiment described later, such an MFR range is preferred. In this specification, the MFR of polyethylene is measured by Method A under the conditions of a temperature of 190°C and a load of 2.16 kg, in accordance with JIS K7210-1:2014.

[0226] The melting point (Tm) of the polyethylene constituting the stretched film (2) is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 110°C or higher, even more preferably 115°C or higher, particularly preferably 120°C or higher, and preferably 140°C or lower, for example, 100°C or higher and 140°C or lower, from the viewpoint of the strength and heat resistance of the polyethylene film and the stretched film.

[0227] Preferably, the polyethylene film comprises a polyethylene layer containing high-density polyethylene and polyethylene other than said high-density polyethylene as a layer constituting its second surface, or a polyethylene layer containing at least one polymer selected from the group consisting of high-density polyethylene and medium-density polyethylene, and polyethylene other than said polymer. The polyethylene film of the first embodiment comprises a polyethylene layer containing high-density polyethylene and polyethylene other than high-density polyethylene as a layer constituting its second surface. Hereinafter, the layer constituting the second surface of the polyethylene film of the first embodiment will also be referred to as the "polyethylene layer (S2)". The stretched film of the polyethylene film of the first embodiment will also be referred to as the "stretched film of the first embodiment (2)". The polyethylene film of the second embodiment comprises, as a layer constituting its second surface, a polyethylene layer containing at least one polymer selected from the group consisting of high-density polyethylene and medium-density polyethylene, and polyethylene other than the polymer (hereinafter also referred to as "other polyethylene"), or a polyethylene layer containing high-density polyethylene and medium-density polyethylene (hereinafter, these polyethylene layers are also referred to as "polyethylene layer (3)"). The stretched film of the polyethylene film of the second embodiment is also referred to as "stretched film of the second embodiment (2)". Such stretched polyethylene films have, for example, high heat resistance, specifically, excellent resistance to drying during anchor coat layer formation and heating during heat sealing, as well as excellent resistance to vapor deposition during vapor deposition, and excellent adhesion to the anchor coat layer.

[0228] Unless otherwise specified, the following matters apply to both the first and second aspects.

[0229] Examples of polyethylenes other than high-density polyethylene in the first embodiment include medium-density polyethylene, linear low-density polyethylene, and low-density polyethylene. Among these, medium-density polyethylene or linear low-density polyethylene is preferred. In one embodiment, the polyethylene layer (S2) preferably contains high-density polyethylene and medium-density polyethylene. Such a stretched polyethylene film has, for example, high impact resistance, and a packaging container with excellent tear resistance can be made using the laminate described later. Furthermore, such a stretched polyethylene film has, for example, high rigidity, which specifically allows for an increase in the transport speed of the stretched film when performing vapor deposition, and therefore increases productivity. In one embodiment, the polyethylene layer (S2) preferably contains high-density polyethylene and linear low-density polyethylene. Such a polyethylene film has excellent stretchability, for example. A stretched polyethylene film tends to have better adhesion to the anchor coat layer, for example.

[0230] In the second embodiment, the other polyethylene mentioned above includes, for example, at least one selected from the group consisting of linear low-density polyethylene and high-pressure low-density polyethylene, which may be linear low-density polyethylene, high-pressure low-density polyethylene, or a mixture of linear low-density polyethylene and high-pressure low-density polyethylene. Among these, linear low-density polyethylene is preferred. The polyethylene layer (3) preferably contains high-density polyethylene and linear high-density polyethylene. Such polyethylene films have excellent stretchability, for example. A stretched film of such polyethylene film has high impact resistance, for example, and a packaging container with excellent tear resistance can be made using a laminate described later. Furthermore, a stretched film of such polyethylene film has high rigidity, for example, which allows for an increase in the transport speed of the stretched film when performing vapor deposition, and therefore increases productivity.

[0231] The stretched film described above exhibits excellent adhesion to the anchor coat layer. The reason for this is not entirely clear, but it is presumed to be due to the following: When forming the anchor coat layer on the second surface of a polyethylene film or its stretched film, surface treatment such as corona treatment may be performed on the second surface as a pretreatment. Layers containing high-density polyethylene and other polyethylenes such as medium-density polyethylene, and their stretched layers, tend to have higher efficiency in surface treatment (e.g., introduction rate of polar groups) compared to layers containing only high-density polyethylene and their stretched layers. For this reason, layers containing high-density polyethylene and other polyethylenes such as medium-density polyethylene, and their stretched layers, exhibit excellent adhesion to the anchor coat layer after surface treatment.

[0232] Examples of high-density polyethylene include ethylene homopolymers and ethylene-α-olefin copolymers. Examples of α-olefins include the above-mentioned α-olefins having 3 to 20 carbon atoms, with α-olefins having 3 to 8 carbon atoms being preferred, and α-olefins having 4 to 8 carbon atoms being more preferred. Examples of ethylene-α-olefin copolymers include ethylene-1-butene copolymer (C4-HDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymer (C6-HDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymer (C8-HDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomers are not limited to those listed above, and further comonomers may be used. For example, high-density polyethylene produced using a metallocene catalyst is preferred.

[0233] Examples of medium-density polyethylene include ethylene homopolymers and ethylene-α-olefin copolymers. Examples of α-olefins include the above-mentioned α-olefins having 3 to 20 carbon atoms, with α-olefins having 3 to 8 carbon atoms being preferred, and α-olefins having 4 to 8 carbon atoms being more preferred. Examples of ethylene-α-olefin copolymers include ethylene-1-butene copolymer (C4-MDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymer (C6-MDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymer (C8-MDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomers are not limited to those listed above, and further comonomers may be used. For example, medium-density polyethylene produced using a metallocene catalyst is preferred.

[0234] High-density polyethylene may be, for example, a homopolymer of ethylene, an ethylene-α-olefin copolymer, or a mixture thereof. Medium-density polyethylene may be, for example, a homopolymer of ethylene, an ethylene-α-olefin copolymer, or a mixture thereof.

[0235] In the second embodiment, the ethylene-α-olefin copolymer is preferred as the high-density polyethylene and the medium-density polyethylene, respectively. A polyethylene film containing such high-density polyethylene and / or medium-density polyethylene exhibits excellent biaxial stretchability, particularly in the width direction. This is presumed to be because the side chains derived from the α-olefin suppress tearing of the film during stretching. As the ethylene-α-olefin copolymer, polyethylene obtained by polymerizing ethylene and a small amount of α-olefin by polymerization using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst is preferred, and polyethylene produced using a metallocene catalyst is more preferred. The density of high-density polyethylene is preferably 0.945 g / cm³. 3exceeding 0.960 g / cm³ 3 The following applies: The density of medium-density polyethylene is preferably 0.930 g / cm³. 3 Exceeding 0.945 g / cm³ 3 The density can be adjusted, for example, by the amount of constituent units derived from α-olefin, which is a comonomer in the ethylene-α-olefin copolymer.

[0236] The polyethylene layer (S2) may, for example, contain a mixture of high-density polyethylene and polyethylene other than high-density polyethylene as its main component, or it may contain a mixture of high-density polyethylene and medium-density polyethylene or linear low-density polyethylene as its main component. The main component being the above mixture means that the content of the above mixture in the polyethylene layer (S2) is more than 50% by mass, and this content is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0237] From the viewpoint of heat resistance, the content of high-density polyethylene in the polyethylene layer (S2) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and particularly preferably 25% by mass or more. From the viewpoint of anchor coat layer formation and adhesion, the content of high-density polyethylene in the polyethylene layer (S2) is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, even more preferably 75% by mass or less, and particularly preferably 60% by mass or less, 50% by mass or less, or 40% by mass or less.

[0238] When the above-mentioned content of high-density polyethylene is small, surface treatment tends to further improve the adhesion between the second surface of the stretched film and the anchor coat layer. This is presumed to be because, for example, high-density polyethylene has high crystallinity, and surface treatments such as corona treatment may not adequately introduce polar groups into the high-density polyethylene. However, when the above-mentioned content of high-density polyethylene is small, surface treatments such as corona treatment can adequately introduce polar groups into the polyethylene. Furthermore, when the above-mentioned content of high-density polyethylene is small, the appearance, surface smoothness, and transparency of the film tend to be superior.

[0239] From the viewpoint of anchor coat layer formation and adhesion, the content of medium-density polyethylene or linear low-density polyethylene in the polyethylene layer (S2) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, and particularly preferably 40% by mass or more, 50% by mass or more, or 60% by mass or more. From the viewpoint of heat resistance, the content of medium-density polyethylene or linear low-density polyethylene in the polyethylene layer (S2) is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and particularly preferably 75% by mass or less.

[0240] The polyethylene content in the polyethylene layer (S2) 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.

[0241] The polyethylene layer (S2) may contain resin materials other than polyethylene. Examples of resin materials other than polyethylene include polyolefins other than polyethylene, polyesters, polyamides, (meth)acrylic resins, vinyl resins, cellulose resins, and ionomer resins.

[0242] The polyethylene layer (S2) may contain additives. Examples of additives include crosslinking agents, antioxidants, UV absorbers, light stabilizers, antiblocking agents, slip agents, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins.

[0243] In one embodiment, the stretched film is a stretched film of a single-layer polyethylene film comprising a polyethylene layer (S2). In one embodiment, the stretched film is a stretched film of a polyethylene film comprising one or more polyethylene layers and a polyethylene layer (S2).

[0244] The polyethylene layer described above contains polyethylene as its main component. Preferred polyethylenes include, for example, high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. The polyethylene content in the polyethylene 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. The polyethylene layer may have the same composition as the polyethylene layer (S2). The polyethylene layer may contain resin materials other than polyethylene. The polyethylene layer described above may contain the additive described above.

[0245] The polyethylene layer (3) may mainly contain a mixture of at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene and other polyethylenes. The polyethylene layer (3) may, for example, contain a mixture of high-density polyethylene and other polyethylenes as its main component, a mixture of medium-density polyethylene and other polyethylenes as its main component, or a mixture of high-density polyethylene, medium-density polyethylene and other polyethylenes as its main component. The statement that the main component is the above mixture means that the content of the above mixture in the polyethylene layer (3) is more than 50% by mass. The above content is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. The high-density polyethylene mentioned above may be, for example, a homopolymer of ethylene, an ethylene-α-olefin copolymer, or a mixture thereof. The medium-density polyethylene mentioned above may be, for example, a homopolymer of ethylene, an ethylene-α-olefin copolymer, or a mixture thereof.

[0246] The total content of high-density polyethylene and medium-density polyethylene in the polyethylene layer (3) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and may also be 30% by mass or more, 35% by mass or more, or 40% by mass or more, from the viewpoint of heat resistance. The total content of high-density polyethylene and medium-density polyethylene in the polyethylene layer (3) is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, and may also be 70% by mass or less, 65% by mass or less, or 60% by mass or less, from the viewpoint of biaxial tractability and, if the polyethylene layer (3) is a layer constituting the second surface of the polyethylene film, from the viewpoint of anchor coat layer formation and adhesion. The total content of high-density polyethylene and medium-density polyethylene in the polyethylene layer (3) is, for example, 10% by mass or more and 90% by mass or less, preferably 20% by mass or more and 60% by mass or less.

[0247] This paragraph describes the case where the polyethylene layer (3) is the layer constituting the second surface of the polyethylene film. When the sum of the above-mentioned proportions of high-density polyethylene and medium-density polyethylene is small, the adhesion between the second surface of the stretched film and the anchor coat layer tends to be further improved by the surface treatment described later. This is presumed to be because, for example, high-density polyethylene has high crystallinity, and in some cases, polar groups cannot be sufficiently introduced into high-density polyethylene by surface treatments such as corona treatment. However, when the sum of the above-mentioned proportions is small, polar groups can be sufficiently introduced into polyethylene by surface treatments such as corona treatment. In addition, when the above-mentioned proportions are small, the appearance, surface smoothness, and transparency of the film tend to be superior.

[0248] From the viewpoint of biaxial stretchability and, if the polyethylene layer (3) is a layer constituting the second surface of the polyethylene film, from the viewpoint of anchor coat layer formation and adhesion, it is preferable that the polyethylene layer (3) further contains linear low-density polyethylene in addition to at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, and more preferably that it further contains linear low-density polyethylene in addition to high-density polyethylene.

[0249] Examples of linear low-density polyethylene include ethylene-α-olefin copolymers. Examples of α-olefins include the α-olefins with 3 to 20 carbon atoms mentioned above, with α-olefins with 3 to 8 carbon atoms being preferred, and α-olefins with 4 to 8 carbon atoms being 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. The density of the linear low-density polyethylene is preferably 0.900 g / cm³. 3 More than 0.930g / cm 3 The following applies:

[0250] The content of linear low-density polyethylene in the polyethylene layer (3) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and may also be 30% by mass or more, 35% by mass or more, or 40% by mass or more, from the viewpoint of biaxial tractability and, if the polyethylene layer (3) is a layer constituting the second surface of the polyethylene film, the formability and adhesion of the anchor coat layer. From the viewpoint of heat resistance, the content of linear low-density polyethylene in the polyethylene layer (3) is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, and may also be 70% by mass or less, 65% by mass or less, or 60% by mass or less. The content of linear low-density polyethylene in the polyethylene layer (3) is, for example, 10% by mass or more and 90% by mass or less, preferably 40% by mass or more and 80% by mass or less.

[0251] The polyethylene layer (3) contains polyethylene as its main component. The polyethylene content in the polyethylene layer (3) 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.

[0252] In one embodiment, the polyethylene layer (3) may contain a resin material other than polyethylene. Examples of resin materials other than polyethylene include polyolefins other than polyethylene, polyesters, polyamides, (meth)acrylic resins, vinyl resins, cellulose resins, and ionomer resins.

[0253] The polyethylene layer (3) may contain additives. Examples of additives include crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, antiblocking agents, slip agents, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins.

[0254] The polyethylene contained in the polyethylene layer (3) is 0.930 g / cm³. 3Super 0.960g / cm 3 Preferably, the following density is observed: The density of the polyethylene contained in the polyethylene layer (3) is preferably 0.931 g / cm³. 3 More than 0.955g / cm 3 More preferably, 0.931 g / cm³ 3 More than 0.950g / cm 3 The following applies:

[0255] The polyethylene layer (3) contains two or more types of polyethylene with different densities. The density of the polyethylene refers to the density of the mixture of the two or more types of polyethylene. This density is measured for polyethylene sampled from the layer in accordance with JIS K7112-2:2023 (density gradient pipe method, 23°C). If this measurement is difficult, the average density D calculated according to the formula described later is used. av This may be the density of the polyethylene constituting the layer.

[0256] In one embodiment, the stretched film is a stretched film of a single-layer polyethylene film consisting of polyethylene layers (3). In one embodiment, the stretched film is a stretched film of a polyethylene film having two or more polyethylene layers, wherein the layer constituting the second surface of the polyethylene film is a polyethylene layer (3), and preferably, all polyethylene layers constituting the polyethylene film are polyethylene layers (3).

[0257] The polyethylene layer described above contains polyethylene as its main component. Preferred polyethylenes include, for example, high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. The polyethylene content in the polyethylene 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. The polyethylene layer may contain resin materials other than polyethylene. The polyethylene layer described above may contain the additive described above.

[0258] The polyethylene content in the polyethylene film and its stretched film is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 85% by mass or more or 90% by mass or more. A barrier layer comprising such a stretched film can be suitably used as a base material constituting packaging materials such as polyethylene-based monomaterial packaging materials. A laminate (or packaging container) comprising such a stretched film has excellent recyclability, for example.

[0259] In one embodiment, the polyethylene film and its stretched film have a multilayer structure of two or more layers. The number of layers of the film is preferably two or more, more preferably three or more, preferably nine or fewer, more preferably seven or fewer, for example, two to nine layers. Specifically, the number of layers of the polyethylene film and its stretched film is three, five, seven, or nine layers. Films having a multilayer structure have an excellent balance of, for example, strength, rigidity, heat resistance, transparency, and printability.

[0260] In a polyethylene film having a multilayer structure and a stretched film thereof, the density of the polyethylene constituting each layer may be the same or different. For example, the film may have a density gradient in each polyethylene layer. A film having a density gradient in each polyethylene layer exhibits excellent strength, rigidity, heat resistance, and stretchability.

[0261] In a polyethylene film and its stretched film, any adjacent layers selected from each polyethylene layer are referred to as layer (i) and layer (ii). The absolute difference between the density of the polyethylene constituting layer (i) and the density of the polyethylene constituting layer (ii) is preferably 0.030 g / cm³ in both cases. 3 More preferably, 0.025 g / cm³ 3 More preferably, 0.020 g / cm³ 3 The following is particularly preferred: 0.010 g / cm³ 3as follows. Such a film has excellent interlayer adhesion, for example, excellent drop resistance.

[0262] When the polyethylene layer contains two or more polyethylenes having different densities, the density of the above polyethylene means the density of a mixture of two or more polyethylenes. The density is measured in accordance with JIS K7112-2:2023 (density gradient tube method, 23°C) for polyethylene collected from the layer. When the measurement is difficult, the average density D calculated according to the following formula av may be used as the density of polyethylene constituting the layer.

[0263] D av = ΣW i ×D i In the formula, Σ means that the sum of W i ×D i is obtained for i from 1 to n (where n types of polyethylene are present), n is an integer of 2 or more, W i represents the mass fraction of the i-th polyethylene, D i represents the density (g / cm 3 ) of the i-th polyethylene.

[0264] The polyethylene film and its stretched film preferably have a multilayer structure. In one embodiment, the polyethylene film and its stretched film include at least a first surface resin layer containing polyethylene as a main component, a polyethylene intermediate layer containing polyethylene as a main component, and a second surface resin layer containing polyethylene as a main component, provided in this order in the lamination direction. However, when adjacent layers constituting the film have the same resin composition and cannot be distinguished from each other, the adjacent layers may be integrated to form one layer.

[0265] The second surface resin layer of the polyethylene film according to the first aspect is a polyethylene layer (S2). In the second embodiment, at least the second surface resin layer of the polyethylene film is a polyethylene layer (3). In the polyethylene film, from the viewpoint of heat resistance, it is preferable that at least one layer selected from the group consisting of a first surface resin layer and a polyethylene intermediate layer is a polyethylene layer (3) or a layer made of at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, and it is more preferable that both the first surface resin layer and the polyethylene intermediate layer are layers made of a polyethylene layer (3) or at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene.

[0266] The first surface resin layer constitutes the first surface of the film. The second surface resin layer constitutes the second surface of the film. The above film may include two or more polyethylene intermediate layers.

[0267] The compositions of the first and second surface resin layers may be the same or different. The thicknesses of the first and second surface resin layers may be the same or different. If the film comprises two or more polyethylene intermediate layers, the compositions of the polyethylene intermediate layers may be the same or different, and the thicknesses of the polyethylene intermediate layers may be the same or different. The compositions of the surface resin layer and the polyethylene intermediate layer may be the same or different. The thicknesses of the surface resin layer and the polyethylene intermediate layer may be the same or different.

[0268] In one embodiment, the stretched film is a film obtained by stretching a polyethylene film. Stretching can improve, for example, the strength, rigidity, heat resistance, transparency, and printability of the polyethylene film. The stretching may be uniaxial stretching or biaxial stretching. Biaxial stretching may be sequential biaxial stretching using methods such as the tenter frame method, or simultaneous biaxial stretching.

[0269] In the first embodiment, the stretching ratio when stretching in the machine direction (film flow direction, MD direction) is preferably 2 times or more, more preferably 3 times or more, preferably 10 times or less, more preferably 7 times or less, for example 2 times or more and 10 times or less. In the first embodiment, the stretching ratio when stretching in the width direction (direction perpendicular to the MD direction, TD direction) is preferably 2 times or more, more preferably 3 times or more, preferably 10 times or less, more preferably 7 times or less, for example 2 times or more and 10 times or less. The stretched film (2) of the first embodiment is preferably a film obtained by uniaxially stretching a polyethylene film, that is, a uniaxially stretched film, and more specifically, a film obtained by uniaxially stretching a polyethylene film in the MD direction.

[0270] In the second embodiment, the stretching ratio when stretching in the machine direction (film flow direction, MD direction) is preferably 2 times or more, more preferably 3 times or more, preferably 15 times or less, more preferably 10 times or less, for example 2 times or more and 15 times or less. In the second embodiment, the stretching ratio when stretching in the width direction (direction perpendicular to the MD direction, TD direction) is preferably 2 times or more, more preferably 3 times or more, preferably 15 times or less, more preferably 10 times or less, for example 2 times or more and 15 times or less. The stretched film (2) of the second embodiment is preferably a film obtained by biaxially stretching a polyethylene film, that is, a biaxially oriented film, and more specifically, a film obtained by biaxially stretching a polyethylene film in the MD direction and the TD direction.

[0271] The thickness of the stretched film (2) is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, and particularly preferably 30 μm or less, for example, 5 μm or more and 200 μm or less. A stretched film (2) with a thickness of the lower limit or more has excellent properties such as strength, rigidity and heat resistance. A stretched film (2) with a thickness of the upper limit or less has excellent properties such as processability.

[0272] The stretched film (2) can be produced, for example, by forming films of the materials constituting each layer to produce a polyethylene film (single-layer film or laminated film), and then stretching the film. Examples of film formation methods include the inflation method and the T-die-casting method. In the first embodiment, the inflation method is preferred, and in the second embodiment, the T-die-casting method is preferred from the viewpoint of productivity. When producing a polyethylene film by the inflation method, the polyethylene MFR is preferably 0.2 g / 10 min to 5 g / 10 min, more preferably 0.5 g / 10 min to 3 g / 10 min, from the viewpoint of film-forming properties and processability.

[0273] In one embodiment, the stretched film (2) is a film obtained by stretching a co-extruded film. In one embodiment, the stretched film (2) is a film obtained by co-extruding a material constituting a first surface resin layer, a material constituting a polyethylene intermediate layer, and a material constituting a second surface resin layer in this order in the lamination direction using an inflation method or a T-die-casting method, and then stretching the resulting co-extruded film.

[0274] Hereafter, the polyethylene layer will also be referred to as the "PE layer." In one embodiment, the polyethylene film and its stretched film are at least, The first surface resin layer, The first PE layer, The second PE layer, The third PE layer, A second surface resin layer, The above layers are arranged in this order, and each of the above layers contains polyethylene as its main component. However, if the resin composition of adjacent layers constituting the above film is the same and they are indistinguishable from one another, the adjacent layers may be integrated to form a single layer.

[0275] In a second embodiment, at least the second surface resin layer of the polyethylene film is a polyethylene layer (3). In the polyethylene film, from the viewpoint of heat resistance, it is preferable that at least one layer selected from the group consisting of the first surface resin layer, the first PE layer, the second PE layer, and the third PE layer is a polyethylene layer (3), or a layer made of at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene, and it is more preferable that all of the above layers are polyethylene layers (3), or layers made of at least one type of polyethylene selected from the group consisting of high-density polyethylene and medium-density polyethylene.

[0276] The compositions of the first and second surface resin layers may be the same or different. The thicknesses of the first and second surface resin layers may be the same or different. The compositions of the first to third PE layers may be the same or different. The thicknesses of the first to third PE layers may be the same or different. The compositions of the above surface resin layers and PE layers may be the same or different. The thicknesses of the above surface resin layers and PE layers may be the same or different.

[0277] The following describes specific examples of the first embodiment (films (α) to (γ)). In one embodiment, the polyethylene film is The first surface resin layer contains medium-density polyethylene and high-density polyethylene. The first PE layer contains medium-density polyethylene and linear low-density polyethylene. The second PE layer contains linear low-density polyethylene as its main component. The third PE layer contains medium-density polyethylene and linear low-density polyethylene. The second surface resin layer contains medium-density polyethylene and high-density polyethylene. This is a film (hereinafter also referred to as "film (α)"). A polyethylene film having such a structure has, for example, excellent stretchability. The stretched film has, for example, excellent anchor coat layer formation and adhesion, strength, and heat resistance. High-density polyethylene contributes, for example, to improved heat resistance. Medium-density polyethylene contributes, for example, to improved rigidity. Linear low-density polyethylene contributes, for example, to improved stretchability.

[0278] In the first and second surface resin layers of the film (α), the total proportion of medium-density polyethylene and high-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, independently of each other. In the first and second surface resin layers of the film (α), the content ratio of medium-density polyethylene to high-density polyethylene (content of medium-density polyethylene / content of high-density polyethylene) is preferably 0.25 to 4, more preferably 0.4 to 3, even more preferably 1.1 to 3, and particularly preferably 1.5 to 3, independently by mass.

[0279] In the first and third PE layers of film (α), the total proportion of medium-density polyethylene and linear low-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, independently of each other. In the first and third PE layers of film (α), the content ratio of medium-density polyethylene to linear low-density polyethylene (content of medium-density polyethylene / content of linear low-density polyethylene) is preferably 0.25 or more and 4 or less, more preferably 0.4 or more and 2.4 or less, and even more preferably 0.8 or more and 2.4 or less, independently by mass.

[0280] In the second PE layer of film (α), the content of linear low-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0281] In one embodiment, the polyethylene film is The first surface resin layer contains high-density polyethylene and medium-density polyethylene. The first PE layer contains medium-density polyethylene as its main component. The second PE layer contains linear low-density polyethylene and medium-density polyethylene. The third PE layer contains medium-density polyethylene as its main component. The second surface resin layer contains high-density polyethylene and medium-density polyethylene. This is a film (hereinafter also referred to as "film (β)"). A polyethylene film having such a structure has, for example, excellent stretchability. The stretched film has, for example, excellent anchor coat layer formation and adhesion, strength, and heat resistance.

[0282] In the first and second surface resin layers of film (β), the total proportion of high-density polyethylene and medium-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, independently of each other. In the first and second surface resin layers of the film (β), the content ratio of high-density polyethylene to medium-density polyethylene (content of high-density polyethylene / content of medium-density polyethylene) is preferably 0.25 to 4, more preferably 0.4 to 3, even more preferably 1.1 to 3, and particularly preferably 1.5 to 3, independently by mass.

[0283] In the second PE layer of film (β), the total proportion of linear low-density polyethylene and medium-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In the second PE layer of film (β), the content ratio of linear low-density polyethylene to medium-density polyethylene (content of linear low-density polyethylene / content of medium-density polyethylene) is preferably 0.25 or more and 4 or less by mass, more preferably 0.4 or more and 2.4 or less.

[0284] In the first and third PE layers of film (β), the content of medium-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, independently of each other.

[0285] In one embodiment, the polyethylene film is The first surface resin layer contains medium-density polyethylene and high-density polyethylene. The first PE layer contains high-density polyethylene as its main component. The second PE layer contains linear low-density polyethylene as its main component. The third PE layer contains high-density polyethylene as its main component. The second surface resin layer contains medium-density polyethylene and high-density polyethylene. This is a film (hereinafter also referred to as "film (γ)"). A polyethylene film having such a structure has, for example, excellent stretchability. The stretched film has, for example, excellent anchor coat layer formation and adhesion, strength, and heat resistance.

[0286] In the first and second surface resin layers of the film (γ), the total proportion of medium-density polyethylene and high-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, independently of each other. In the first and second surface resin layers of the film (γ), the content ratio of medium-density polyethylene to high-density polyethylene (content of medium-density polyethylene / content of high-density polyethylene) is preferably 1.1 to 5, and more preferably 1.5 to 3, independently by mass.

[0287] In one embodiment of the first and third PE layers of the film (γ), the content of high-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, independently of each other.

[0288] The first and third PE layers of film (γ) may each independently further contain low-density polyethylene. Such a configuration can, for example, further improve the balance of heat resistance, rigidity, and processability of the film. In this embodiment, the total proportion of high-density polyethylene and low-density polyethylene in the first and third PE layers is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, independently. In this embodiment, the content ratio of high-density polyethylene to low-density polyethylene (content of high-density polyethylene / content of low-density polyethylene) in the first and third PE layers is preferably 1 to 4, more preferably 1.5 to 3, independently, on a mass basis.

[0289] In one embodiment of the second PE layer of film (γ), the content of linear low-density polyethylene is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0290] The second PE layer of film (γ) may further contain low-density polyethylene. Such a configuration can, for example, further improve the balance between the stretchability and processability of the film. In this embodiment, the total proportion of linear low-density polyethylene and low-density polyethylene in the second PE layer is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In this embodiment, the content ratio of linear low-density polyethylene to low-density polyethylene (content of linear low-density polyethylene / content of low-density polyethylene) in the second PE layer is preferably 1 to 4 by mass, more preferably 1.5 to 3 by mass.

[0291] In the stretched film (2) of the first embodiment, the thickness of the first and second surface resin layers is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 1.5 μm or more, preferably 10 μm or less, more preferably 8 μm or less, even more preferably 5 μm or less, for example, 0.5 μm or more and 10 μm or less.

[0292] In the stretched film (2) of the first embodiment, the thicknesses of the first and second surface resin layers are, independently of the thickness of the stretched film, preferably 3% or more, more preferably 5% or more, even more preferably 8% or more, preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less, for example, 3% or more and 25% or less.

[0293] In the stretched film (2) of the first embodiment, the thickness of the polyethylene intermediate layer is preferably 4 μm or more, more preferably 8 μm or more, even more preferably 12 μm or more, preferably 100 μm or less, more preferably 45 μm or less, even more preferably 35 μm or less, particularly preferably 25 μm or less, for example, 4 μm or more and 100 μm or less. A stretched film having a polyethylene intermediate layer with a thickness equal to or greater than the lower limit is, for example, excellent in strength, rigidity, heat resistance and recyclability. A stretched film having a polyethylene intermediate layer with a thickness equal to or less than the upper limit is, for example, excellent in processability. If the stretched film has two or more polyethylene intermediate layers, the above "thickness" means the sum of the thicknesses of each polyethylene intermediate layer.

[0294] In the stretched film (2) of the first embodiment, the thickness of the polyethylene intermediate layer is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, preferably 94% or less, more preferably 90% or less, even more preferably 84% or less, for example, 50% or more and 94% or less, relative to the thickness of the stretched film. If the stretched film comprises two or more polyethylene intermediate layers, the above "thickness" means the sum of the thicknesses of each polyethylene intermediate layer.

[0295] In the stretched film (2) of the first embodiment, the thickness of the first and third PE layers is preferably 1 μm or more, more preferably 1.5 μm or more, even more preferably 2 μm or more, preferably 15 μm or less, more preferably 10 μm or less, even more preferably 8 μm or less, for example, 1 μm or more and 15 μm or less.

[0296] In the stretched film (2) of the first embodiment, the thicknesses of the first and third PE layers are, independently of the thickness of the polyethylene intermediate layer, preferably 5% or more, more preferably 10% or more, even more preferably 15% or more, preferably 40% or less, more preferably 35% or less, even more preferably 30% or less, for example, 5% or more and 40% or less.

[0297] In the stretched film (2) of the first embodiment, the thickness of the second PE layer is preferably 2 μm or more, more preferably 5 μm or more, even more preferably 8 μm or more, preferably 60 μm or less, more preferably 40 μm or less, even more preferably 20 μm or less, for example, 2 μm or more and 60 μm or less.

[0298] In the stretched film (2) of the first embodiment, the thickness of the second PE layer is preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, preferably 90% or less, more preferably 80% or less, even more preferably 70% or less, with respect to the thickness of the polyethylene intermediate layer, for example, 20% or more and 90% or less.

[0299] In the stretched film (2) of the second embodiment, the thicknesses of the first and second surface resin layers are, independently of each other, preferably 0.3 μm or more, more preferably 0.5 μm or more, even more preferably 0.8 μm or more, preferably 15 μm or less, more preferably 10 μm or less, even more preferably 5 μm or less, and particularly preferably 3 μm or less, for example, 0.3 μm or more and 15 μm or less. If the first surface resin layer has protrusions caused by particles, it is preferable that the thickness of the layer be measured in a region where no protrusions caused by particles are formed.

[0300] In the stretched film (2) of the second embodiment, the thicknesses of the first and second surface resin layers are, independently of the thickness of the stretched film, preferably 1% or more, more preferably 2% or more, even more preferably 4% or more, preferably 20% or less, more preferably 15% or less, even more preferably 10% or less, particularly preferably 8% or less, for example, 1% or more and 20% or less.

[0301] In the stretched film (2) of the second embodiment, the thickness of the polyethylene intermediate layer is preferably 6 μm or more, more preferably 10 μm or more, even more preferably 14 μm or more, preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, even more preferably 40 μm or less, particularly preferably 30 μm or less, for example, 6 μm or more and 100 μm or less. A stretched film having a polyethylene intermediate layer with a thickness of the lower limit or more has excellent properties such as strength, rigidity, heat resistance and recyclability. A stretched film having a polyethylene intermediate layer with a thickness of the upper limit or less has excellent properties such as processability. When the stretched film has two or more polyethylene intermediate layers, the above "thickness" means the sum of the thicknesses of each polyethylene intermediate layer.

[0302] In the stretched film (2) of the second embodiment, the thickness of the polyethylene intermediate layer is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, particularly preferably 84% or more, preferably 98% or less, more preferably 96% or less, even more preferably 92% or less, for example, 60% or more and 98% or less, relative to the thickness of the stretched film. If the stretched film comprises two or more polyethylene intermediate layers, the above "thickness" means the sum of the thicknesses of each polyethylene intermediate layer.

[0303] In the stretched film (2) of the second embodiment, the thickness of the first and third PE layers is preferably 0.5 μm or more, more preferably 0.8 μm or more, even more preferably 1 μm or more, preferably 18 μm or less, more preferably 13 μm or less, even more preferably 8 μm or less, and particularly preferably 5 μm or less, for example, 0.5 μm or more and 18 μm or less.

[0304] In the stretched film (2) of the second embodiment, the thicknesses of the first and third PE layers are, independently of the thickness of the polyethylene intermediate layer, preferably 3% or more, more preferably 5% or more, even more preferably 7% or more, preferably 25% or less, more preferably 20% or less, even more preferably 15% or less, for example, 3% or more and 25% or less.

[0305] In the stretched film (2) of the second embodiment, the thickness of the second PE layer is preferably 4 μm or more, more preferably 6 μm or more, even more preferably 8 μm or more, preferably 60 μm or less, more preferably 40 μm or less, even more preferably 20 μm or less, for example, 4 μm or more and 60 μm or less.

[0306] In the stretched film (2) of the second embodiment, the thickness of the second PE layer is preferably 50% or more, more preferably 60% or more, even more preferably 70% or more, preferably 94% or less, more preferably 90% or less, even more preferably 86% or less, with respect to the thickness of the polyethylene intermediate layer, for example, 50% or more and 94% or less.

[0307] The ratio of the thickness of the second surface resin layer to the thickness of the first surface resin layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of film symmetry and suppression of curling.

[0308] The ratio of the thickness of the first PE layer to the thickness of the third PE layer is preferably 0.6 to 1.4, more preferably 0.7 to 1.3, even more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1, from the viewpoint of film symmetry and suppression of curling.

[0309] At least one selected from the group consisting of polyethylene films, stretched films, and barrier films may be surface-treated. Such polyethylene films, stretched films, and barrier films have excellent adhesion to other layers, for example. Examples of surface treatment methods include physical treatment and chemical treatment. Examples of physical treatments include corona treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment. Examples of chemical treatments include oxidation treatment using chemicals.

[0310] The following will primarily describe the second aspect. In one embodiment of a polyethylene film and its stretched film, the density of polyethylene in the polyethylene intermediate layer is higher than that of the first surface resin layer, and the density of polyethylene in the second surface resin layer is lower than that of the polyethylene intermediate layer. Such films tend to have an excellent balance of surface smoothness, transparency, printability, vapor deposition adhesion, and heat resistance. When the polyethylene intermediate layer is thicker than the surface resin layer, high heat resistance can be obtained due to the polyethylene intermediate layer. The density difference of polyethylene between the polyethylene intermediate layer and the surface resin layer is, for example, 0.003 g / cm³. 3 That's fine too. The total proportion of high-density polyethylene and medium-density polyethylene will be referred to as "Proportion A" below. This may consist of high-density polyethylene alone, medium-density polyethylene alone, or a mixture of high-density polyethylene and medium-density polyethylene. In one embodiment of a polyethylene film and its stretched film, the content A in the polyethylene intermediate layer is greater than the content A in the first surface resin layer, and the content A in the second surface resin layer is smaller than the content A in the polyethylene intermediate layer. Such films tend to have an excellent balance of surface smoothness, transparency, printability, vapor deposition adhesion, and heat resistance. The difference in content A between the polyethylene intermediate layer and the surface resin layer may be, for example, 10% by mass or more, or 30% by mass or less.

[0311] In one embodiment of a polyethylene film and its stretched film, the density of polyethylene in the polyethylene intermediate layer is lower than the density of polyethylene in the first surface resin layer, and the density of polyethylene in the second surface resin layer is higher than the density of polyethylene in the polyethylene intermediate layer. Such films tend to have an excellent balance between biaxial stretchability and heat resistance. When the polyethylene intermediate layer is thicker than the surface resin layer, high biaxial stretchability can be obtained due to the polyethylene intermediate layer. The density difference of polyethylene between the surface resin layer and the polyethylene intermediate layer is, for example, 0.003 g / cm³. 3 That's fine too. In one embodiment of a polyethylene film and its stretched film, the content A in the polyethylene intermediate layer is smaller than the content A in the first surface resin layer, and the content A in the second surface resin layer is larger than the content A in the polyethylene intermediate layer. Such films tend to have an excellent balance between biaxial stretchability and heat resistance. The difference in content A between the surface resin layer and the polyethylene intermediate layer may be, for example, 10% by mass or more, or 30% by mass or less.

[0312] In one embodiment of a polyethylene film and its stretched film, the densities of polyethylene in the first surface resin layer, the polyethylene intermediate layer, and the second surface resin layer are approximately equal. For example, among the first surface resin layer, the polyethylene intermediate layer, and the second surface resin layer, the difference in density between the layer with the highest polyethylene density and the layer with the lowest polyethylene density is 0.003 g / cm³. 3 It is less than. In one embodiment of the polyethylene film and its stretched film, the content ratio A in the first surface resin layer, the polyethylene intermediate layer, and the second surface resin layer are approximately the same. For example, among the first surface resin layer, the polyethylene intermediate layer, and the second surface resin layer, the difference in content ratio A between the layer with the highest content ratio A and the layer with the lowest content ratio A is less than 10% by mass.

[0313] Furthermore, if each of the above layers contains two or more types of polyethylene with different densities, the density of the polyethylene refers to the density of the mixture of the two or more types of polyethylene. The method for measuring and calculating the density is as described above.

[0314] The first surface resin layer may further contain particles. By including particles in the first surface resin layer, for example, the antiblocking or slipperiness of the polyethylene film and its stretched film can be improved. From the viewpoint of the formation of the anchor coat layer and the vapor-deposited film, it is preferable that the second surface resin layer does not contain particles.

[0315] Examples of particles include inorganic compound-based antiblocking agents and resin particle-based antiblocking agents. Specific examples of inorganic compound-based antiblocking agents include oxides such as silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, and zinc oxide; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; carbonates such as magnesium carbonate and calcium carbonate; sulfates such as calcium sulfate and barium sulfate; silicates such as magnesium silicate, aluminum silicate, calcium silicate, and aluminosilicate; and others such as kaolin, talc, and diatomaceous earth. Specific examples of resin particles include resin particles composed of resin components such as polymethyl methacrylate (PMMA), polystyrene, methyl methacrylate-styrene copolymer, polyester, polyamide, polytetrafluoroethylene, epoxy resin, urea resin, and phenolic resin. The resin particles may be crosslinked or non-crosslinked.

[0316] From a cost and other perspective, the particles may also be inorganic compound-based antiblocking agents. The particles may be resin particle-based antiblocking agents. For example, in the case of a barrier film in which one surface resin layer contains a resin particle-based antiblocking agent and the other surface resin layer has an anchor coat layer and a vapor-deposited film, the possibility of the particles damaging the vapor-deposited film when the film is stored in a roll can be reduced. This is because resin particle-based antiblocking agents are usually less rough and softer than inorganic compound-based antiblocking agents.

[0317] The average particle diameter is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 2 μm or more, preferably 6 μm or less, more preferably 5.5 μm or less, even more preferably 5 μm or less, for example, 0.5 μm or more and 6 μm or less. The average particle diameter refers to the average value (arithmetic mean diameter) of particle diameters measured for 100 randomly selected non-aggregated particles by observing the cross-section in the thickness direction of each layer with a scanning electron microscope (SEM).

[0318] When the first surface resin layer contains particles, the particle content is preferably 100 ppm or more, more preferably 500 ppm or more, even more preferably 1,000 ppm or more, preferably 10,000 ppm or less, more preferably 8,000 ppm or less, even more preferably 5,000 ppm or less, based on the mass of the first surface resin layer, for example, 100 ppm or more and 10,000 ppm or less.

[0319] In a stretched film, when the first surface resin layer contains particles, the ratio of the average particle diameter to the thickness of the first surface resin layer (average particle diameter / thickness) is preferably 0.5 or more and 5.0 or less, more preferably 0.8 or more and 4.0 or less, and even more preferably 1.0 or more and 3.5 or less.

[0320] <<Polypropylene film and its stretched film>> Polypropylene films and their stretched films contain polypropylene as the main component. The polypropylene may be any of the following: propylene homopolymer (homopolypropylene), propylene random copolymer (random polypropylene) such as propylene-α-olefin random copolymer, or propylene block copolymer (block polypropylene) such as propylene-α-olefin block copolymer, or a mixture of two or more selected from these. From the viewpoint of reducing environmental impact, biomass-derived polypropylene or mechanically or chemically recycled polypropylene may be used as the polypropylene.

[0321] In this disclosure, polypropylene means a propylene homopolymer, or a polymer in which the proportion of propylene-derived structural units in the total repeating structural units is greater than the proportion of structural units derived from any comonomer. In this polymer, the proportion of propylene-derived structural units may be, for example, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 80 mol% or more. The above proportion is measured by NMR spectroscopy.

[0322] A propylene homopolymer is a polymer consisting solely of propylene. A propylene random copolymer is a random copolymer of propylene and α-olefins other than propylene. A propylene block copolymer is a copolymer having polymer blocks made of propylene and polymer blocks made of α-olefins other than propylene. Examples of α-olefins other than propylene include α-olefins having 2 to 20 carbon atoms, specifically ethylene, 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.

[0323] Among polypropylenes, propylene random copolymer is preferred from the viewpoint of transparency, propylene homopolymer is preferred when rigidity and heat resistance of the packaging container are important, and propylene block copolymer is preferred when impact resistance of the packaging container is important.

[0324] The MFR of polypropylene is preferably 0.1 g / 10 min or more, more preferably 0.2 g / 10 min or more, even more preferably 0.5 g / 10 min or more, preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 10 g / 10 min or less, for example, 0.1 g / 10 min or more and 50 g / 10 min or less. In this specification, the MFR of polypropylene is measured by Method A in accordance with JIS K7210-1:2014, under conditions of a temperature of 230°C and a load of 2.16 kg.

[0325] The density of polypropylene is, for example, 0.88 g / cm³. 3 More than 0.92g / cm 3 The following applies: The melting point (Tm) of polypropylene is preferably 120°C or higher, more preferably 125°C or higher, preferably 170°C or lower, more preferably 165°C or lower, for example, 120°C or higher and 170°C or lower, from the viewpoint of strength and heat resistance.

[0326] Polypropylene films may contain resin materials other than polypropylene. Examples of such resin materials include polyolefins other than polypropylene, (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins. The polypropylene film may contain biomass polypropylene. The polypropylene film may contain recycled polypropylene. The polypropylene film may contain the above-mentioned additives.

[0327] The polypropylene content in the polypropylene film and its stretched film is preferably more than 50% by mass, more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. A barrier layer comprising such a stretched film can be suitably used as a base material constituting packaging materials such as polypropylene-based monomaterial packaging materials. A laminate (or packaging container) comprising such a stretched film has excellent recyclability, for example.

[0328] The stretching process may be uniaxial stretching or biaxial stretching. 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, preferably 15 times or less, more preferably 10 times or less, for example 2 times or more and 15 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, preferably 15 times or less, more preferably 10 times or less, for example 2 times or more and 15 times or less. The stretched polypropylene film may be, for example, a uniaxially stretched film or a biaxially stretched film, with biaxially stretched film being preferred.

[0329] The polypropylene film may have a single-layer structure or a multi-layer structure. From the viewpoint of strength and heat resistance, the thickness of the stretched polypropylene film is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. From the viewpoint of processability, it is preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, and particularly preferably 40 μm or less, for example, 5 μm or more and 200 μm or less.

[0330] At least one selected from the group consisting of polypropylene film, stretched film, and barrier film may be subjected to the above surface treatment. Such a film, for example, has excellent adhesion to other layers.

[0331] <Anchor Coat Layer> In one embodiment, the barrier layer comprises an anchor coat layer containing a resin material having polar groups on the second surface of the stretched film (2), and a second vapor-deposited film on the anchor coat layer. That is, in one embodiment, the barrier layer comprises an anchor coat layer between the stretched film and the second vapor-deposited film. The second vapor-deposited film formed on the anchor coat layer has high adhesion, is dense with few gaps, has excellent flexibility, and has excellent gas barrier properties. Furthermore, a packaging container made using a laminate with such a barrier layer has high laminate strength. In one embodiment, the anchor coat layer is in contact with the stretched film.

[0332] The barrier layer may also include an anchor coat layer on the first surface of the stretched film. In this case, it is preferable that the layer constituting the first surface of the polyethylene film has the same composition as the polyethylene layer (S2) or is the polyethylene layer (3).

[0333] The anchor coat layer contains a resin material having polar groups. Examples of polar groups include carboxyl groups, carboxylic acid anhydride groups, hydroxyl groups, amino groups, thiol groups, sulfo groups, epoxy groups, carbonyl groups, ester groups, amide groups, urethane groups, and halogen groups. Among these, carboxyl groups, hydroxyl groups, amino groups, carbonyl groups, ester groups, and urethane groups are preferred from the viewpoint of exhibiting the above-mentioned effects more effectively, and carboxyl groups, hydroxyl groups, ester groups, and urethane groups are more preferred.

[0334] Examples of resin materials having polar groups include hydroxyl group-containing (meth)acrylic resins, hydroxyl group-free (meth)acrylic resins, urethane resins, ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyesters, polyamides (e.g., nylon 6, nylon 6,6, MXD nylon, amorphous nylon), and polyethyleneimines, with hydroxyl group-containing (meth)acrylic resins, urethane resins, ethylene-vinyl alcohol copolymers, and polyvinyl alcohol being preferred. By using such resin materials, the adhesion of the vapor-deposited film formed on the anchor coat layer can be significantly improved, and its gas barrier properties can be effectively enhanced.

[0335] The content of the resin material having polar groups in the anchor coat layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0336] The anchor coat layer may contain resin materials other than resin materials having polar groups. The anchor coat layer may contain the above-mentioned additives.

[0337] The anchor coat layer can be formed by applying a coating solution obtained by dissolving or dispersing a material such as a resin material having polar groups in water or a suitable organic solvent to a polyolefin film or a stretched film, and then drying (curing if necessary). Examples of coating methods include known coating methods such as roll coating, gravure coating, knife coating, dip coating, and spray coating. The anchor coat layer may also be formed using, for example, an aqueous emulsion or a solvent-based emulsion. Examples of aqueous emulsions include polyamide emulsions and polyurethane emulsions. Examples of solvent-based emulsions include polyester emulsions.

[0338] In one embodiment, the anchor coat layer may be formed using a composition containing a functional group-containing (meth)acrylic resin, an isocyanate compound as a curing agent, and optionally a silane coupling agent.

[0339] Examples of functional group-containing (meth)acrylic resins include hydroxyl group-containing (meth)acrylic resins, carboxyl group-containing (meth)acrylic resins, epoxy group-containing (meth)acrylic resins, and amino group-containing (meth)acrylic resins. Among these, hydroxyl group-containing (meth)acrylic resins are particularly preferred because the reaction rate can be easily controlled.

[0340] In one embodiment, a hydroxyl group-containing (meth)acrylic resin is produced from a monomer that does not have hydroxyl groups and a hydroxyl group-containing (meth)acrylic monomer. Examples of monomers that do not have hydroxyl groups include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, and lauryl (meth)acrylate, styrene monomers such as styrene and vinyltoluene, and vinyl ester monomers such as vinyl acetate and vinyl propionate. Examples of hydroxyl group-containing (meth)acrylic monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate.

[0341] Functional group-containing (meth)acrylic resins other than hydroxyl group-containing (meth)acrylic resins can, in one embodiment, be produced from a monomer that does not have a hydroxyl group, and a carboxyl group-containing monomer such as (meth)acrylic acid, maleic acid, and itaconic acid; an epoxy group-containing monomer such as glycidyl (meth)acrylate; or a nitrogen-containing monomer such as (meth)acrylamide, N-methylol(meth)acrylamide, diacetone(meth)acrylamide, and dimethylaminoethyl (meth)acrylate.

[0342] The following explanation primarily describes the case where hydroxyl group-containing (meth)acrylic resin is used. The glass transition temperature (Tg) of the hydroxyl group-containing (meth)acrylic resin is preferably 50°C to 200°C, more preferably 70°C to 150°C. A Tg of 50°C or higher can suppress blocking, for example. A Tg of 200°C or lower can improve curability, for example. The Tg is obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012 (using a test specimen conditioned according to 3.(3)).

[0343] The number-average molecular weight of the hydroxyl group-containing (meth)acrylic resin is preferably 10,000 or more and 100,000 or less. A number-average molecular weight of 10,000 or more can suppress blocking, for example. A number-average molecular weight of 100,000 or less can improve coating properties, for example. The number-average molecular weight is measured by gel permeation chromatography (GPC) in accordance with JIS K7252-1:2008 and is expressed as a standard polystyrene equivalent.

[0344] The hydroxyl value of the hydroxyl-containing (meth)acrylic resin is preferably 20 mg KOH / g or more and 200 mg KOH / g or less, more preferably 30 mg KOH / g or more and 150 mg KOH / g or less. When the hydroxyl value is 20 mg KOH / g or more, for example, interlayer adhesion can be improved and gas barrier properties can also be improved. The hydroxyl value is measured in accordance with JIS K0070:1992.

[0345] The isocyanate compound used as a curing agent is any compound known as an isocyanate curing agent that reacts with a hydroxyl group-containing (meth)acrylic resin to form a urethane bond. The anchor coat layer formed using such a composition contains, for example, a urethane resin. Examples of isocyanate compounds include aromatic diisocyanate monomers such as tolylene diisocyanate, xylylene diisocyanate, and 4,4-diphenylmethane diisocyanate; aliphatic diisocyanate monomers such as hexamethylene diisocyanate; and polymers or derivatives thereof.

[0346] Silane coupling agents are organosilicon compounds that contain both a hydrolysis group that reacts with inorganic substances and an organic functional group that reacts with organic substances within a single molecule. Examples of hydrolysis groups that react with inorganic substances include alkoxy groups such as methoxy and ethoxy groups, acetoxy groups, and chloro groups. Preferred organic functional groups that react with organic substances are functional groups that react with hydroxyl groups in hydroxyl group-containing (meth)acrylic resins or isocyanate groups in isocyanate compounds. Examples include isocyanate groups, amino groups, epoxy groups, and mercapto groups, and may also be vinyl groups and methacrylate groups.

[0347] The organosilicon compounds described above may have alkyl or phenyl groups that do not react with either inorganic or organic substances. The organosilicon compounds may be mixed with silicon compounds that do not have organic functional groups, such as alkoxysilanes that have only hydrolysis groups.

[0348] Examples of silane coupling agents include amino group-containing silane coupling agents such as N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane; epoxy group-containing silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; mercapto group-containing silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatetopropyltriethoxysilane and 3-isocyanatetopropyltrimethoxysilane.

[0349] Any solvent can be used to dissolve the hydroxyl group-containing (meth)acrylic resin, as long as it maintains the fluidity of the anchor coating agent during application and provides a smooth anchor coating layer. Examples of such solvents include alcohol-based solvents such as methanol, ethanol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate; glycol-based solvents such as 2-butoxyethanol and propylene glycol monomethyl ether; and hydrocarbon-based solvents such as toluene, xylene, n-hexane, and methylcyclohexane. A mixture of two or more solvents selected from these may also be used.

[0350] In anchor coating agents, the molar ratio of isocyanate groups in the isocyanate compound to hydroxyl groups in the hydroxyl group-containing (meth)acrylic resin is preferably 0.3 to 3.0. Such a molar ratio can improve, for example, curability and blocking resistance.

[0351] The content of the silane coupling agent in the anchor coating agent is preferably 3 to 80 parts by mass per 100 parts by mass of the solid content of the hydroxyl group-containing (meth)acrylic resin. This configuration can improve, for example, interlayer adhesion and blocking resistance.

[0352] For example, an anchor coating agent is prepared by mixing a hydroxyl group-containing (meth)acrylic resin, an isocyanate compound, and optionally a silane coupling agent in any desired ratio, and this anchor coating agent is coated onto a polyolefin film or a stretched film to form an anchor coating layer.

[0353] The thickness of the anchor coat layer is preferably 0.02 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and particularly preferably 0.2 μm or more. A barrier film having such a configuration can be used to produce packaging containers that have excellent adhesion to vapor-deposited films, excellent gas barrier properties, and excellent lamination strength. The thickness of the anchor coat layer is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, and even more preferably 1 μm or less. A barrier film having such a configuration can be used to produce packaging containers that are easy to process and have excellent recyclability. The thickness of the anchor coat layer is, for example, between 0.02 μm and 10 μm.

[0354] The ratio of the thickness of the anchor coat layer to the total thickness of the stretched film and the anchor coat layer is preferably 0.08% or more, more preferably 0.2% or more, even more preferably 0.3% or more, and particularly preferably 0.5% or more. A barrier film having such a configuration can be used to produce packaging containers that have excellent adhesion to vapor-deposited films, excellent gas barrier properties, and excellent lamination strength. The ratio of the thickness of the anchor coat layer to the total thickness of the stretched film and the anchor coat layer is preferably 20% or less, more preferably 10% or less, even more preferably 5% or less, and particularly preferably 3% or less. A barrier film having such a configuration can be used to produce packaging containers that are easy to process and have excellent recyclability. The above percentage of the anchor coat layer thickness is, for example, between 0.08% and 20%.

[0355] A coated film having an anchor coat layer on a stretched film can be manufactured offline. Specifically, a polyolefin film can be produced by forming a film of polyolefin or its resin composition using an inflation method or a T-die-casting method, stretching the film, and then applying an anchor coat agent to the film and drying it to produce the above-mentioned coated film. A coated film having an anchor coat layer on a stretched film can also be manufactured in-line. Specifically, a polyolefin film can be produced by forming a film of polyolefin or its resin composition using an inflation method or a T-die-casting method, applying an anchor coat agent to the film and drying it, and then stretching the film after the coating has been applied to produce the coated film. A coated film having an anchor coat layer on a biaxially oriented film can also be manufactured in-line. Specifically, a polyolefin film can be produced by forming a film of polyolefin or its resin composition using a T-die casting method or an inflation method, stretching the film in the mechanical direction (MD direction), applying an anchor coat agent to the film and drying it, and then stretching the coated film in the width direction (TD direction) to produce the coated film. Alternatively, stretching in the MD direction may be performed first, followed by stretching in the TD direction.

[0356] It is preferable to perform the above surface treatment on the film before applying the anchor coating agent. The drying conditions when forming the anchor coating layer from the anchor coating agent are preferably 50°C or higher, more preferably 70°C or higher, preferably 150°C or lower, more preferably 120°C or lower, for example, 50°C to 150°C, and the drying time is preferably 1 second to 10 minutes.

[0357] <Second vapor-deposited film> The barrier layer has a second vapor-deposited film and exhibits excellent gas barrier properties. Packaging containers made using a laminate comprising such a barrier layer (barrier film) and a barrier heat-seal layer (barrier sealant film) exhibit excellent gas barrier properties. The second vapor-deposited film may consist of two or more layers. In one embodiment, the barrier layer comprises a second vapor-deposited film on the surface resin layer (G) or (AH) of the stretched film, or on the anchor coat layer on the stretched film. Such a barrier layer offers, for example, superior gas barrier properties, and if the vapor-deposited film is a metal vapor-deposited film, it offers superior brightness.

[0358] In one embodiment, the barrier layer comprises a polyolefin layer (e.g., a polyethylene layer or a polypropylene layer), a surface resin layer (G) or (AH), and a second vapor-deposited film, in this order in the lamination direction. In one embodiment, the second vapor-deposited film is in contact with the surface resin layer (G) or (AH) of the stretched film.

[0359] In one embodiment, the barrier layer comprises, in this order, at least one polyolefin layer, an adhesive resin layer, a surface resin layer (G), and a second vapor-deposited film. The barrier layer in the above embodiment comprises, for example, a first polyolefin layer as a first surface resin layer, a second polyolefin layer, a third polyolefin layer, an adhesive resin layer, a surface resin layer (G) as a second surface resin layer, and a second vapor-deposited film, in this order. In the case of a stretched film (X), the polyolefin layer is replaced with a polyethylene layer.

[0360] In one embodiment, the barrier layer comprises, in this order, at least one polyolefin layer, a surface resin layer (AH), and a second vapor-deposited film. The barrier layer in the above embodiment comprises, for example, a first polyolefin layer as a first surface resin layer, a second polyolefin layer, a third polyolefin layer, a fourth polyolefin layer, a surface resin layer (AH) as a second surface resin layer, and a second vapor-deposited film, in this order. In the case of a stretched film (X), the polyolefin layer is replaced with a polyethylene layer.

[0361] In one embodiment, the barrier layer comprises a polyolefin layer (e.g., a polyethylene layer or a polypropylene layer), an anchor coat layer, and a second vapor-deposited film, in this order in the lamination direction. In one embodiment, the second vapor-deposited film is in contact with the anchor coat layer.

[0362] In one embodiment, the vapor-deposited film is provided on a second surface of the stretched film, but not on a first surface of the stretched film. In another embodiment, the vapor-deposited film is provided on a second surface resin layer (surface resin layer (G) or (AH)) or anchor coat layer of the stretched film, but not on a first surface resin layer of the stretched film. In the case of a barrier layer having vapor-deposited films on both sides of a stretched film, the vapor-deposited films may deteriorate due to contact or friction between the vapor-deposited films when the barrier layer (barrier film) is stored, for example, in a roll. With the barrier layer of the above embodiment, such deterioration of the vapor-deposited films can be suppressed.

[0363] The vapor-deposited film is 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 the vapor-deposited films, aluminum vapor-deposited films, aluminum oxide (alumina) vapor-deposited films, silicon oxide (silica) vapor-deposited films, and silicon carbide oxide vapor-deposited films are preferred.

[0364] The thickness of the second vapor-deposited film is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more, from the viewpoint of gas barrier properties. The thickness of the second vapor-deposited film is preferably 150 nm or less, more preferably 100 nm or less, and even more preferably 80 nm or less, from the viewpoint of suppressing crack generation in the vapor-deposited film and the recyclability of the packaging container. The above thickness is, for example, 1 nm or more and 150 nm or less.

[0365] 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 improve oxygen barrier properties and water vapor barrier properties while maintaining the productivity of the barrier layer, for example. The OD value is measured in accordance with JIS K7361-1:1997.

[0366] The surface of the deposited film may be subjected to the above-mentioned surface treatment. Such a deposited film, for example, has excellent adhesion to adjacent layers.

[0367] Methods for forming deposited films include, for example, physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition.

[0368] The vacuum level of the deposition chamber before oxygen introduction was 10 -2 ~10 -8 A bar of approximately mbar is preferred, and after oxygen introduction, 10 -1 ~10 -6 A pressure of approximately mbar is preferred. The amount of oxygen introduced will vary depending on the size of the vapor deposition machine. The introduced oxygen may be mixed with inert gases such as argon, helium, and nitrogen as carrier gases, to the extent that it does not cause any problems. The transport speed of the target film on which the vapor deposition film is formed is, for example, 10 m / min to 800 m / min.

[0369] <Barrier Coat Layer> The barrier layer may further comprise a barrier coat layer on the second vapor-deposited film. That is, the barrier layer may further comprise a barrier coat layer on the surface of the second vapor-deposited film opposite to the surface facing the stretched film or the anchor coat layer. Such a barrier layer has excellent scratch resistance and gas barrier properties, and if the second vapor-deposited film is composed of inorganic oxides such as aluminum oxide and silicon oxide, it can effectively suppress the occurrence of cracks in the second vapor-deposited film and suppress the decrease in gas barrier properties.

[0370] In one embodiment, the barrier layer comprises a stretched film (1), an inorganic oxide vapor-deposited film, and a barrier coat layer in that order. In another embodiment, the barrier layer comprises a stretched film (2), an anchor coat layer, an inorganic oxide vapor-deposited film, and a barrier coat layer in that order.

[0371] In one embodiment, the barrier coating layer contains a gas barrier resin. A barrier layer having such a layer exhibits even better gas barrier properties. The barrier coating layer can be formed, for example, by dissolving or dispersing a material such as a gas barrier resin in water or a suitable organic solvent, applying the resulting coating solution to a vapor-deposited film, and drying it.

[0372] Examples of gas barrier resins include ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyamides, polyvinylidene chloride, polyesters, polyether polyols, polyester polyols, polyurethanes, polyacrylonitriles, and (meth)acrylic resins.

[0373] In one embodiment, the content of the gas barrier resin in the barrier coating layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. Such a layer exhibits excellent gas barrier properties, for example.

[0374] The barrier coat layer may contain the above-mentioned additives.

[0375] The thickness of the barrier coating layer containing the 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 barrier coating layer containing the gas barrier resin is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of processability of the barrier layer and recyclability of the packaging container. The above thickness is, for example, 0.01 μm or more and 10 μm or less.

[0376] In another embodiment, the 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 optionally adding water, optionally an organic solvent, and optionally a sol-gel catalyst. The gas barrier coating film contains hydrolyzed polycondensates obtained by hydrolysis and polycondensation of the above metal alkoxide, etc., by the sol-gel method. By providing such a film on a vapor-deposited film, when the vapor-deposited film is composed of inorganic oxides, the gas barrier properties can be improved and the occurrence of cracks in the vapor-deposited film can be effectively suppressed.

[0377] Examples of metal alkoxides include alkoxysilanes, specifically tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0378] 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 copolymer may be used, or both may be used in combination. Alternatively, 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 metal alkoxide.

[0379] As the silane coupling agent, known organic reactive group-containing organoalkoxysilanes can be used, and organoalkoxysilanes having an epoxy group are preferred, such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The amount of silane coupling agent used is preferably 1 to 20 parts by mass per 100 parts by mass of metal alkoxide.

[0380] The gas barrier composition may contain, preferably, 0.1 moles or more, more preferably 0.5 moles or more, of water per mole of metal alkoxide, and preferably 100 moles or less, more preferably 60 moles or less. By setting the water content above the lower limit, for example, the oxygen barrier and water vapor barrier properties of the barrier film can be improved. By setting the water content below the upper limit, for example, hydrolysis reactions can be carried out rapidly.

[0381] The gas barrier composition may contain an organic solvent. Examples of organic solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol.

[0382] Acids or amine compounds are preferred as catalysts for the sol-gel method.

[0383] Methods for applying the gas barrier composition include, for example, roll coating such as gravure roll coaters, spray coating, spin coating, dipping, brushing, bar coating, and application methods such as applicators.

[0384] The following describes one embodiment of a method for forming a gas barrier coating film. A gas barrier composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and optionally a silane coupling agent. A polycondensation reaction gradually proceeds within the composition. The composition is applied to a vapor-deposited film by a conventional method and dried. This drying further promotes the polycondensation of the metal alkoxide and the water-soluble polymer (and the silane coupling agent if the composition contains one), forming a composite polymer layer. Multiple composite polymer layers may be laminated by repeating the above operation. For example, the applied composition is heated for 1 second to 10 minutes at a temperature preferably 20°C or higher, more preferably 50°C or higher, even more preferably 70°C or higher, preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower. In this way, a gas barrier coating film can be formed.

[0385] The thickness of the gas barrier coating is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, preferably 100 μm or less, more preferably 50 μm or less, even more preferably 5 μm or less, even 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 has, for example, excellent gas barrier properties, can suppress the occurrence of cracks in vapor-deposited films composed of inorganic oxides, and has excellent recyclability and processability for packaging containers.

[0386] <Print layer> The barrier layer may further comprise a printed layer, which will be described later. The printed layer may be provided on the surface of the second vapor-deposited film, on the surface of the barrier coating layer, or on the surface of the first surface resin layer.

[0387] <Layer structure of the barrier layer> Below are some examples of the layer structure of the barrier layer (barrier film), referring to the drawings. In the case of the stretched film (X), the polyolefin layer below should be read as the polyethylene layer. The barrier layer (barrier film) 1 shown in Figure 1A comprises, in this order, a polyolefin layer 10, a surface resin layer (G) or (AH) 20, and a second vapor-deposited film 42. The barrier layer (barrier film) 1 shown in Figure 1B comprises, in this order, a polyolefin layer 10, an adhesive resin layer 30, a surface resin layer (G) 20, and a second vapor-deposited film 42. The barrier layer (barrier film) 1 shown in Figure 1C comprises a polyolefin layer 10, an anchor coat layer 22, and a second vapor-deposited film 42 in this order.

[0388] <Gas barrier properties of barrier layers (barrier films)> Oxygen permeability of the barrier layer (unit: cc / (m) 2 The value of (day·atm) 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 oxygen permeability may be, for example, 0.01. Oxygen permeability is measured in accordance with JIS K7126-2:2006 at a temperature of 23°C and a humidity of 90%RH.

[0389] Water vapor transmission rate of the barrier layer (unit: g / (m) 2 The minimum value for water vapor transmission (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 for water vapor transmission may be, for example, 0.01. Water vapor transmission is measured in accordance with JIS K7129-2:2019 at a temperature of 40°C and a humidity of 90%RH.

[0390] [Laminated structure] The laminate of the present disclosure comprises, in this order, at least, a heat seal layer, a first vapor-deposited film, an adhesive layer, and a barrier layer. In one embodiment, the laminate of the present disclosure comprises, in this order, at least, a heat seal layer, a first vapor-deposited film, a first adhesive layer, a barrier layer, a second adhesive layer, and a polyolefin substrate layer.

[0391] In one embodiment, the laminate of the present disclosure does not include either polyethylene terephthalate film or aluminum foil. This improves the recyclability of the laminate of the present disclosure and the packaging container comprising the laminate. The laminates of the present disclosure can be suitably used as packaging materials. For example, the laminates of the present disclosure can be suitably used as packaging materials for making packaging bags.

[0392] The content of polyolefin (e.g., polyethylene or polypropylene) in the entire laminate of this disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. This allows, for example, the production of polyolefinized (e.g., polyethyleneized) packaging containers using the above laminate, thereby improving the recyclability of the packaging containers. There is no particular upper limit to the content of polyolefin (e.g., polyethylene or polypropylene), but it may be as high as 99% by mass.

[0393] The total thickness of the laminate of this disclosure is preferably 40 μm or more, more preferably 60 μm or more, even more preferably 80 μm or more, preferably 400 μm or less, more preferably 350 μm or less, even more preferably 300 μm or less, for example, 40 μm or more and 400 μm or less.

[0394] <Base material layer, etc.> The laminate of this disclosure comprises the barrier layer described above. The laminate of this disclosure may comprise two or more barrier layers. Details of the barrier layer are as described above, and a detailed explanation is omitted here. In the above laminate, the orientation of the barrier layer is not particularly limited. The barrier layer may be arranged such that the stretched film faces the heat seal layer and the second vapor-deposited film faces the opposite side of the heat seal layer or the polyolefin substrate layer, or the second vapor-deposited film faces the heat seal layer and the stretched film faces the opposite side of the heat seal layer or the polyolefin substrate layer. If the above laminate does not include a further polyolefin stretched substrate, it is preferable that the barrier layer is arranged such that the second vapor-deposited film faces the heat seal layer and the stretched film faces the opposite side of the heat seal layer, from the viewpoint of suppressing deterioration of the second vapor-deposited film.

[0395] The laminate of this disclosure may further comprise a polyolefin stretched substrate. The polyolefin stretched substrate is a polyolefin substrate that has been stretched. The polyolefin stretched substrate contains polyolefin as the main component. Examples of polyolefins include polyethylene, polypropylene, polybutene, and polymethylpentene. Among these, polyethylene and polypropylene are preferred, and polyethylene is more preferred. As polyolefin stretched substrates, for example, a polyethylene stretched substrate containing polyethylene as the main component and a polypropylene stretched substrate containing polypropylene as the main component are preferred, and a polyethylene stretched substrate is more preferred. The stretching treatment may be uniaxial stretching or biaxial stretching. Details of the stretching treatment are as described above and will not be explained in this section. The polyolefin stretched substrate may be, for example, a uniaxially stretched substrate or a biaxially stretched substrate.

[0396] The polyolefin stretched substrate may contain biomass polyolefins. The polyolefin stretched substrate may contain recycled polyolefin. The polyolefin stretched substrate may contain the above-mentioned additives.

[0397] The polyolefin content in the polyolefin stretched substrate is preferably more than 50% by mass, more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0398] The polyolefin stretched substrate may have a single-layer structure or a multi-layer structure. The thickness of the polyolefin stretched 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, and preferably 300 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less, for example, 5 μm or more and 300 μm or less, from the viewpoint of the processability of the laminate.

[0399] The polyolefin stretched substrate may be subjected to the above-mentioned surface treatment. Such a polyolefin stretched substrate has excellent adhesion to adjacent layers, for example. An anchor coat layer may be formed on the surface of the polyolefin stretched substrate using a conventionally known anchor coat agent.

[0400] The laminate further comprising a polyolefin stretched substrate may, for example, comprise a heat seal layer, a barrier layer, and a polyolefin stretched substrate in this order, or a heat seal layer, a polyolefin stretched substrate, and a barrier layer in this order.

[0401] In one embodiment, the laminate of the present disclosure comprises, in this order, a heat-seal layer containing polyethylene or polypropylene as the main component, a barrier layer containing a polypropylene stretched film, and a polypropylene substrate layer. In one embodiment, the laminate of the present disclosure comprises, in this order, a heat-seal layer containing polyethylene or polypropylene as the main component, a barrier layer containing a polypropylene-based stretched film, and a polyethylene substrate layer. In one embodiment, the laminate of the present disclosure comprises, in this order, a heat-seal layer containing polyethylene as the main component, a barrier layer containing a polyethylene-based stretched film, and a polyethylene substrate layer. In one embodiment, the laminate of the present disclosure comprises, in this order, a heat-seal layer containing polyethylene as the main component, a barrier layer containing a polyethylene-based stretched film, and a polypropylene substrate layer.

[0402] <Print layer> The laminate of the present disclosure may include a printed layer on one or both surfaces of the barrier layer and / or polyolefin substrate layer as described above. The printed layer may be formed, for example, on any surface of the polyolefin substrate layer. In one embodiment, the laminate of the present disclosure includes a printed layer on the surface of the polyolefin substrate layer facing the barrier layer, as this can suppress contact between the printed layer and the outside air and suppress deterioration of the printed layer over time.

[0403] The printed layer includes an image. Examples of images include letters, figures, patterns, symbols, and combinations thereof. The image may also include textual information such as the product name, the name of the item in the packaging, the manufacturer, and the name of the raw materials. The image may be a solid color (a so-called solid image).

[0404] In one embodiment, the printed layer contains a coloring agent. Examples of colorants include pigments such as inorganic pigments and organic pigments, as well as dyes such as acid dyes, direct dyes, disperse dyes, oil-soluble dyes, metal-containing oil-soluble dyes, and sublimable dyes. Furthermore, fluorescent materials such as ultraviolet-emitting materials that emit fluorescence upon absorbing ultraviolet light, and infrared-emitting materials that emit fluorescence upon absorbing infrared light, can also be used as colorants.

[0405] The colorant content in the printed layer is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The colorant content in the printed layer is preferably 90% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less. The above content is, for example, 1% by mass or more and 90% by mass or less.

[0406] In one embodiment, the printed layer contains a resin material in addition to a colorant. Examples of resin materials include thermoplastic resins, cured products of thermosetting resins, and cured products of energy ray-curable compounds. Examples of thermoplastic resins include polyolefins, chlorinated polyolefins, polystyrene, (meth)acrylic resins, vinyl resins, acetal resins, polyesters, polyurethanes, polycarbonates, polyamides, polyimides, cellulose resins, petroleum resins, and fluororesins. Examples of thermosetting resins include phenolic resins, melamine resins, urea resins, epoxy resins, unsaturated polyesters, thermosetting polyurethanes, silicone resins, and (meth)acrylic-based thermosetting resins. Examples of energy ray-curable compounds include polyfunctional (meth)acrylate compounds.

[0407] The resin material content in the printed layer is preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more. The resin material content in the printed layer is preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less. The above content is, for example, 10% by mass or more and 99% by mass or less.

[0408] The printed layer may contain the above-mentioned additives.

[0409] The printed layer can be formed, for example, using an ink composition containing the above-mentioned components and, optionally, a solvent. 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 environmental impact, the printed layer may be formed by flexographic printing. From the viewpoint of reducing environmental impact, the printed layer may also be formed using biomass-derived ink.

[0410] 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, 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.

[0411] <Heat seal layer> The laminate of this disclosure comprises a heat seal layer. In recent years, there has been a growing demand for recycling packaging containers from the perspective of reducing environmental impact. From the standpoint of recyclability, it is preferable that the base material and the heat-seal layer be composed of the same type of resin material (monomaterialization). In one embodiment, the heat-seal layer contains polyethylene or polyolefin such as polypropylene as its main component. This makes it possible to achieve monomaterialization of the packaging container. Such packaging containers have excellent recyclability, and for example, after collecting used packaging containers, there is no need to separate the base material and the heat-seal layer.

[0412] For example, if the stretched film is a polypropylene-based stretched film, it is preferable that the heat seal layer mainly contains polypropylene or polyethylene. For example, if the stretched film is a polyethylene-based stretched film, it is preferable that the heat seal layer mainly contains polyethylene.

[0413] In one embodiment, the heat-seal layer contains polyethylene as its main component. This makes it possible to make the packaging container polyolefinic (e.g., polyethyleneic). Such packaging containers have excellent recyclability, and for example, after collecting used packaging containers, there is no need to separate the barrier layer and the heat-seal layer. The laminate in which the heat-seal layer contains polyethylene as its main component can be suitably used as a packaging material such as a polyethylene-based monomaterial packaging material.

[0414] Examples of polyethylene included in the heat seal layer include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. From the viewpoint of heat sealability, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene are preferred. From the viewpoint of reducing environmental impact, biomass polyethylene and / or recycled polyethylene may be used as the polyethylene.

[0415] From the viewpoint of heat sealability, it is preferable that the heat seal layer 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 linear low-density polyethylene may be greater than the content (mass%) of low-density polyethylene.

[0416] The melting point (Tm) of the polyethylene contained in the heat seal layer is preferably 80°C or higher, more preferably 85°C or higher, preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower, for example, 80°C to 140°C, from the viewpoint of balancing heat resistance and heat sealability.

[0417] The polyethylene MFR contained in the heat seal layer 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, preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 10 g / 10 min or less, for example, 0.1 g / 10 min or more and 50 g / 10 min or less, from the viewpoint of film-forming properties and processability.

[0418] The polyethylene content 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 having such a heat-seal layer has excellent recyclability, for example.

[0419] The heat seal layer may contain the above-mentioned additives.

[0420] The heat seal layer may have a single-layer structure or a multi-layer structure. In one embodiment, the heat seal layer comprises, in this order, a layer containing linear low-density polyethylene as the main component, a layer containing high-density polyethylene as the main component, and a layer containing linear low-density polyethylene as the main component. Such a heat seal layer has an excellent balance of heat sealability and rigidity. In another embodiment, the heat seal layer comprises, in this order, a first HS layer containing linear low-density polyethylene as the main component, a second HS layer containing linear low-density polyethylene as the main component, and a third HS layer containing linear low-density polyethylene or ultra-low-density polyethylene as the main component. Such a heat seal layer has excellent heat sealability. If the resin composition of adjacent layers constituting the heat seal layer is the same and they are indistinguishable from each other, the adjacent layers may be integrated to form a single layer, and the same applies hereinafter.

[0421] The surface resin layer on the barrier layer side of the heat seal layer may be the surface resin layer (G) or (AH) described above. The details of the surface resin layer (G) or (AH) (e.g., resin composition) are as described above. The first vapor-deposited film provided on the surface of the surface resin layer (G) or (AH) tends to have excellent adhesion to the surface resin layer (G) or (AH) and exhibit good gas barrier properties. The main component of the surface resin layer (G) is preferably an ethylene-vinyl alcohol copolymer, polyvinyl alcohol, or polyamide, with ethylene-vinyl alcohol copolymer or polyamide being more preferred. The surface resin layer (AH) preferably contains polyethylene and an adhesive resin, or polypropylene and an adhesive resin. The thickness of the surface resin layer (G) or (AH) in the heat seal layer is preferably 0.5 μm or more and 10 μm or less, more preferably 1.0 μm or more and 8.0 μm or less, and even more preferably 2.0 μm or more and 6.0 μm or less.

[0422] In one embodiment, the heat seal layer comprises a surface resin layer (G), an adhesive resin layer if necessary, and one or more polyolefin layers in this order, or a surface resin layer (AH) and one or more polyolefin layers in this order.

[0423] The details of the adhesive resin layer (e.g., resin composition) are as described above. The thickness of the adhesive resin layer is preferably 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm, and even more preferably 2.0 μm to 6.0 μm.

[0424] The polyolefin layer contains polyolefin as its main component. Examples of polyolefins include polyethylene and polypropylene. Low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene are preferred as polyethylene. Random polypropylene is preferred as polypropylene.

[0425] In one embodiment, the heat seal layer comprises a surface resin layer (G), an adhesive resin layer, a first HS layer, a second HS layer, and a third HS layer in this order. In one embodiment, the heat seal layer comprises a surface resin layer (AH), a first HS layer, a second HS layer, and a third HS layer in this order. There may be two or more second HS layers.

[0426] The first HS layer faces the barrier layer, and the third HS layer faces the opposite side of the barrier layer. For example, when a packaging container is made using the above laminate, the third HS layer faces the storage area of ​​the packaging bag.

[0427] In one embodiment, the laminate comprises, in this order, a third HS layer, a second HS layer, a first HS layer, optionally an adhesive resin layer, a surface resin layer (G) or (AH), a first vapor-deposited film, a first adhesive layer, a barrier layer, and optionally a second adhesive layer and a polyolefin substrate layer. In one embodiment, the laminate comprises, in this order, a third HS layer, a second HS layer, a first HS layer, an anchor coat layer, a first vapor-deposited film, a first adhesive layer, a barrier layer, and optionally a second adhesive layer and a polyolefin substrate layer.

[0428] The third HS layer has a density of 0.920 g / cm³. 3 It is preferable, and more preferable, that the following linear low-density polyethylene or ultra-low-density polyethylene be the main component. The density of the above polyethylene is preferably 0.900 g / cm³. 3 Exceeding 0.915 g / cm³ 3 More preferably, 0.910 g / cm³ 3 More preferably, 0.906 g / cm³ 3The following applies: When the stretched film in the barrier layer is a polyethylene-based stretched film and / or the polyolefin substrate layer is a polyethylene substrate layer, low-temperature heat sealing is desirable from the viewpoint of suppressing thermal degradation during heat sealing. In such a configuration, sufficient heat seal strength can be obtained even when heat sealing is performed at a low temperature (e.g., around 140°C).

[0429] The melting point (Tm) of the polyethylene contained in the third HS layer is preferably 80°C or higher, more preferably 85°C or higher, preferably 120°C or lower, more preferably 110°C or lower, and even more preferably 100°C or lower, for example, 80°C or higher and 120°C or lower, from the viewpoint of low-temperature heat sealability and the like.

[0430] The density in the third HS layer is 0.920 g / cm³. 3 The content of the following linear low-density polyethylene or ultra-low-density polyethylene is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0431] In one embodiment, the third HS layer further contains an antiblocking agent. This configuration can improve the antiblocking properties of the heat seal layer, for example. Examples of antiblocking agents include inorganic antiblocking agents and organic antiblocking agents.

[0432] Examples of inorganic antiblocking agents include oxides such as silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, and zinc oxide; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; carbonates such as magnesium carbonate and calcium carbonate; sulfates such as calcium sulfate and barium sulfate; silicates such as magnesium silicate, aluminum silicate, calcium silicate, and aluminosilicate; kaolin, talc, zeolite (synthetic zeolite or natural zeolite), and diatomaceous earth. Examples of organic antiblocking agents include (meth)acrylic resin particles such as polymethyl methacrylate (PMMA) resin particles, styrene resin particles, and melamine resin particles.

[0433] The average particle size of the antiblocking agent is, for example, between 1 μm and 10 μm. The average particle size is the number-average particle size measured using a laser diffraction particle size distribution analyzer (SALD-2000J, manufactured by Shimadzu Corporation) or an equivalent device.

[0434] In one embodiment, the content ratio of the antiblocking agent in the third HS layer is, for example, 0.1% by mass or more and 15% by mass or less, or 0.2% by mass or more and 10% by mass or less.

[0435] The ratio of the thickness of the third HS layer to the total thickness of the first, second, and third HS layers is preferably 2% to 40%, more preferably 5% to 35%, and even more preferably 10% to 30%.

[0436] The density of the linear low-density polyethylene contained in the first HS layer is preferably 0.906 g / cm³. 3 Exceeding 0.925 g / cm³ 3 More preferably, 0.910 g / cm³ 3 exceeding 0.920 g / cm³ 3 More preferably, 0.915 g / cm³ 3 exceeding 0.920 g / cm³ 3 The following applies: The density of the linear low-density polyethylene contained in the first HS layer is preferably 0.920 g / cm³. 3 The following applies: The content of linear low-density polyethylene in the first HS layer is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0437] The ratio of the thickness of the first HS layer to the total thickness of the first, second, and third HS layers is preferably 2% to 60%, more preferably 5% to 55%, and even more preferably 10% to 50%. The surface of the first HS layer may be subjected to the above-mentioned surface treatment.

[0438] The density of the linear low-density polyethylene contained in the second HS layer is not particularly limited. For example, the linear low-density polyethylene contained in the second HS layer may be the same as or different from the linear low-density polyethylene contained in the first HS layer. The content of linear low-density polyethylene in the second HS layer is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0439] From the viewpoint of improving heat sealability, the density of the linear low-density polyethylene contained in the second HS layer is preferably 0.920 g / cm³. 3 The following is the case: From the viewpoint of increasing rigidity, the density of the linear low-density polyethylene contained in the second HS layer is preferably 0.920 g / cm³. 3 exceeding 0.930 g / cm³ 3 The following applies:

[0440] The ratio of the thickness of the second HS layer to the total thickness of the first, second, and third HS layers is preferably 20% to 96%, more preferably 25% to 90%, and even more preferably 30% to 80%.

[0441] The heat-seal layer (e.g., a second HS layer) may further contain a colorant component. Such a layer functions as a light-shielding layer. A heat-seal layer having such a configuration can be used to produce a packaging container that provides sufficient heat-seal strength even when heat-sealed at low temperatures, has excellent light-shielding properties, and therefore excellent storage stability of the contents.

[0442] Examples of colorant components include pigments and dyes. Examples of pigments include inorganic pigments and organic pigments. Examples of inorganic pigments include white pigments, red pigments, orange pigments, yellow pigments, green pigments, blue pigments, purple pigments, black pigments, metallic pigments, and pearl pigments. Among these, white pigments are preferred from the viewpoint of obtaining a heat-seal layer that exhibits a milky white color.

[0443] Examples of white pigments include titanium dioxide, zinc oxide, zinc sulfide, silicon dioxide, magnesium oxide, zirconium oxide, antimony oxide, aluminum oxide, aluminum hydroxide, calcium carbonate, barium sulfate, and anhydrous calcium silicate. Among these, titanium dioxide is preferred. Examples of black pigments include carbon black, titanium black, titanium carbon, black iron oxide, black titanium dioxide, and graphite.

[0444] Examples of metallic pigments include particles made from elemental metals such as aluminum, silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, and copper, as well as particles made from alloys of these metals. Examples of pearl pigments include pigments having a pearlescent or interference luster, such as titanium dioxide-coated mica, fish scale foil, and bismuth acid chloride.

[0445] Examples of organic pigments include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments), dye chelates (e.g., basic dye chelates and acid dye chelates), nitro pigments, nitroso pigments, and aniline black. Examples of dyes include acid dyes, basic dyes, and reactive dyes.

[0446] In one embodiment, the content ratio of the colorant component in the second HS layer is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less.

[0447] The thickness of the heat seal layer is preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and particularly preferably 25 μm or more, from the viewpoint of heat sealability and recyclability of the packaging container. The thickness of the heat seal layer is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 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.

[0448] The heat seal layer is preferably an unstretched resin film, more preferably an unstretched co-extruded resin film, from the viewpoint of heat sealability, and each layer constituting the heat seal layer is a co-extruded resin layer. The above resin film can be manufactured, for example, by using the T die-casting method or the inflation method. The term "unstretched film" is a concept that includes not only films that are not stretched at all, but also films that are slightly stretched due to the tension applied during film formation.

[0449] For example, an unstretched resin film corresponding to the heat seal layer and a barrier sealant film comprising a first vapor-deposited film may be laminated onto the barrier layer or the corresponding barrier film via an adhesive layer as needed. Examples of the adhesive layer include the adhesive layer described later.

[0450] <First vapor-deposited film> A first vapor-deposited film is provided on the surface resin layer on the barrier layer side of the heat seal layer (for example, the surface resin layer (G) or (AH), or the first HS layer), or on the anchor coat layer provided on the heat seal layer. This configuration improves the gas barrier properties of the laminate, and by providing a metal vapor-deposited film, for example, gloss or light-shielding properties can be imparted to the laminate. In one embodiment, the first vapor-deposited film is in contact with the heat seal layer or the anchor coat layer. The first vapor-deposited film may consist of two or more layers. The details of the vapor-deposited film (e.g., its composition) are as described above and will not be explained further in this section. Specifically, the first vapor-deposited film is preferably an aluminum vapor-deposited film, an aluminum oxide (alumina) vapor-deposited film, a silicon oxide (silica) vapor-deposited film, or a silicon oxide carbide vapor-deposited film.

[0451] The thickness of the first vapor-deposited film is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more, from the viewpoint of gas barrier properties. The thickness of the first vapor-deposited film is preferably 150 nm or less, more preferably 100 nm or less, and even more preferably 80 nm or less, from the viewpoint of suppressing crack generation in the vapor-deposited film and the recyclability of the packaging container. The above thickness is, for example, 1 nm or more and 150 nm or less.

[0452] The combination of the first and second 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 also be a metal vapor-deposited film, and the two 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 also be an aluminum vapor-deposited film, and the two may be the same aluminum vapor-deposited film or different aluminum vapor-deposited films.

[0453] 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. Alternatively, 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 oxide carbide 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 oxide carbide vapor-deposited film and the second vapor-deposited film may be an aluminum vapor-deposited film.

[0454] 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, and the two 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 oxide carbide vapor-deposited film, and the second vapor-deposited film may be an alumina vapor-deposited film, a silica vapor-deposited film, or a silicon oxide carbide vapor-deposited film, and the two may be the same or different. Such a laminate has excellent transparency. Therefore, by using this laminate, for example, packaging containers with excellent visibility of contents, packaging containers that can be used in microwave ovens, and packaging containers that can pass through metal detectors can be manufactured. For example, by using this laminate, packaging containers that do not contain aluminum vapor-deposited films can be manufactured. Consumers can clearly understand that such packaging containers do not contain aluminum vapor-deposited films. Therefore, such packaging containers are easy to separate, and furthermore, the inclusion of foreign matter such as black spots (metallic color) that may occur due to aluminum vapor-deposited films during recycling can be suppressed.

[0455] <Anchor Coat Layer> In one embodiment, the laminate of the present disclosure may further include an anchor coat layer containing a resin material having polar groups between the heat seal layer and the first vapor-deposited film. In this case, the first vapor-deposited film is provided on the anchor coat layer. The first vapor-deposited film formed on the anchor coat layer has high adhesion, is dense with few gaps, has excellent flexibility, and has excellent gas barrier properties. Furthermore, a packaging container made using such a laminate has high laminate strength. In one embodiment, the anchor coat layer is in contact with the heat seal layer. The details of the anchor coat layer (e.g., composition and thickness) are as described above.

[0456] <Barrier Coat Layer> In one embodiment, the laminate of the present disclosure may further comprise a barrier coating layer on the first vapor-deposited film. That is, the laminate may further comprise a barrier coating layer on the surface of the first vapor-deposited film opposite to the surface facing the heat seal layer. Such a laminate has excellent scratch resistance and gas barrier properties, and when the first vapor-deposited film is composed of inorganic oxides such as aluminum oxide and silicon oxide, for example, the occurrence of cracks in the first vapor-deposited film can be effectively suppressed, and the decrease in gas barrier properties can be suppressed. The details of the barrier coat layer are as described above.

[0457] <Adhesive layer> The laminate of this disclosure may include an adhesive layer between any layers, such as between the barrier layer and the heat seal layer or the polyolefin substrate layer. Such a laminate has excellent adhesion between the barrier layer and the heat seal layer or the polyolefin substrate layer.

[0458] In one embodiment, the laminate of the present disclosure comprises, in this order, a heat-seal layer, a first vapor-deposited film, a first adhesive layer, a barrier layer, a second adhesive layer, and a polyolefin substrate layer. Such a laminate exhibits excellent adhesion between the barrier layer, the heat-seal layer, and the polyolefin substrate layer.

[0459] In one embodiment, the adhesive layer may be an adhesive layer composed of an adhesive. The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be a solvent-free adhesive or a solvent-based adhesive. Among these, a solvent-based adhesive is preferred because it has superior resistance to internal contents.

[0460] Examples of solvent-free adhesives, i.e., non-solvent laminate adhesives, include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives, and urethane-based adhesives. Among these, urethane-based adhesives are preferred, and two-component curing type urethane-based adhesives are more preferred.

[0461] 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 type urethane-based adhesives are more preferred.

[0462] In one embodiment, the laminate of the present disclosure may be manufactured by laminating a barrier sealant film corresponding to a barrier heat seal layer, a barrier film corresponding to a barrier layer, and a polyolefin film corresponding to a polyolefin substrate layer using a non-solvent lamination method with a solvent-free adhesive, or by laminating them using a dry lamination method with a solvent-type adhesive.

[0463] The adhesive layer can be formed by applying and drying the adhesive to the barrier layer or the corresponding barrier film, for example, by methods such as the direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, fontein method, and transfer roll coating method.

[0464] 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, 6 μm or less, for example, 0.1 μm or more and 10 μm or less. The thickness of the adhesive layer may also be 2 μm or less.

[0465] 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 thermoplastic resins include high-density polyethylene, medium-density polyethylene, high-pressure low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate methyl copolymer, ethylene-(meth)acrylate ethyl copolymer, ethylene-maleic acid copolymer, ionomer resin, and resins obtained by graft polymerization or copolymerization of polyolefins with unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, or ester monomers. The thermoplastic 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, and two or more of these may be used.

[0466] The extruded resin layer is preferably an extruded polyethylene layer. This allows for a higher polyolefin (e.g., polyethylene) content in the laminate compared to using conventional non-polyethylene adhesives (e.g., two-component curing urethane adhesives). This improves the recyclability of the laminate.

[0467] Examples of polyethylene included in the extruded polyethylene layer include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. Among these, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene are preferred from the viewpoint of interlayer adhesion, and low-density polyethylene is more preferred.

[0468] In one embodiment, the extruded polyethylene layer may contain a polyolefin plastomer and acid-group-containing polyethylene. The content of the polyolefin plastomer in the extruded polyethylene layer is, for example, 60% to 80% by mass, and the content of the acid-group-containing polyethylene is, for example, 20% to 40% by mass. This allows, for example, the melting temperature during melt extrusion to be lowered, and therefore damage to the vapor-deposited film in the barrier layer can be suppressed, the gas barrier properties based on the vapor-deposited film can be maintained, and the adhesion between the vapor-deposited film and the extruded polyethylene layer can be improved.

[0469] Polyolefin plastomers include, for example, polyethylene plastomers. Plastomer is a term used in contrast to elastomer (a polymer that deforms in accordance with an external force when that force is applied, and returns to its original shape in a short time when that force is removed). Plastomers do not exhibit elastic deformation like elastomers, but are polymers that easily undergo plastic deformation.

[0470] Polyethylene plastomer is polyethylene obtained by copolymerizing ethylene and α-olefin using a single-site catalyst such as a metallocene catalyst. Preferred α-olefins include those with 4 to 8 carbon atoms, such as 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene. Specific examples of polyethylene plastomers include ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer.

[0471] From the viewpoint of fusion properties, the density of the polyethylene plastomer is preferably 0.920 g / cm³. 3 More preferably, 0.915 g / cm³ 3 More preferably, 0.910 g / cm³ 3 The density of polyethylene plastomer is 0.850 g / cm³. 3 The above is also acceptable, 0.855 g / cm³ 3 The above is also acceptable, 0.860 g / cm³ 3The above is also acceptable. The density of the polyethylene plastomer is, for example, 0.850 g / cm³. 3 More than 0.920g / cm 3 The following applies:

[0472] The melting point (Tm) of polyethylene plastomer is preferably 115°C or lower, more preferably 110°C or lower, even more preferably 105°C or lower, and particularly preferably 100°C or lower, and may also be 90°C or lower, 80°C or lower, or 70°C or lower. The Tm of polyethylene plastomer may be 40°C or higher, 45°C or higher, or 50°C or higher. For example, the Tm of polyethylene plastomer is 40°C or higher and 115°C or lower.

[0473] The MFR of polyethylene plastomer 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, 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. The MFR of polyethylene plastomer 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.

[0474] Examples of acid-containing polyethylenes include copolymers of ethylene with an unsaturated carboxylic acid or its acid anhydride and optionally other monomers, as well as resins obtained by graft polymerization of polyethylene with an unsaturated carboxylic acid or its acid anhydride. Examples of unsaturated carboxylic acids include monocarboxylic acids such as (meth)acrylic acid and dicarboxylic acids such as maleic acid. Examples of other monomers include (meth)acrylates. In acid group-containing polyethylene, the content of constituent units derived from unsaturated carboxylic acids or their acid anhydrides may be, for example, 0.1% by mass or more, 1% by mass or more, 5% by mass or more, 25% by mass or less, 20% by mass or less, 15% by mass or less, for example, 0.1% by mass or more and 25% by mass or less. In acid group-containing polyethylene, the content of constituent units derived from ethylene may be, for example, more than 50% by mass, 60% by mass or more, 95% by mass or less, 90% by mass or less, for example, more than 50% by mass and 95% by mass or less. The above content is measured by NMR spectroscopy. The density of acid-containing polyethylene is 0.905 g / cm³. 3 The above is also acceptable, 0.910 g / cm³ 3 The above is also acceptable, 0.940 g / cm³ 3 The following is also acceptable: 0.930 g / cm³ 3 The following is also acceptable, for example, 0.905 g / cm³ 3 More than 0.940g / cm 3 The following is also acceptable. Examples of acid-containing polyethylenes include ethylene-(meth)acrylic acid copolymers and ethylene-(meth)acrylic acid-(meth)acrylate copolymers such as ethylene-(meth)acrylic acid-butyl (meth)acrylate copolymers.

[0475] The melt flow rate (MFR) of polyethylene and acid-containing polyethylene in the extruded polyethylene layer is preferably 1 g / 10 min or more, more preferably 2 g / 10 min or more, even more preferably 3 g / 10 min or more, preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 20 g / 10 min or less, for example, 1 g / 10 min or more and 50 g / 10 min or less.

[0476] The melting point (Tm) of polyethylene and acid-containing polyethylene in the extruded polyethylene layer is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower, from the viewpoint of balancing heat resistance and adhesiveness.

[0477] The extruded polyethylene layer may contain biomass polyethylene. The extruded polyethylene layer may contain recycled polyethylene. The extruded polyethylene layer may contain the above-mentioned additives.

[0478] The polyethylene content in the extruded polyethylene layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. With such a configuration, for example, adhesion and recyclability can be improved.

[0479] The thickness of the extruded polyethylene layer is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of interlayer adhesion, and 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, for example, 5 μm or more and 30 μm or less.

[0480] The extruded polyethylene layer may be formed, for example, by melt-extruding polyethylene or a polyethylene-containing resin composition into a barrier layer or the like. The melting temperature at this time is preferably 260°C or higher, more preferably 265°C or higher, preferably 340°C or lower, more preferably 335°C or lower, for example, 260°C or higher and 340°C or lower.

[0481] An anchor coat layer may be provided on the surface where the extruded resin layer in the barrier layer is formed, if necessary. The anchor coat layer is formed with an anchor coat agent. Examples of anchor coat agents include polyurethane-based, polyolefin-based, or epoxy resin-based anchor coat agents. The thickness of the anchor coat layer is, for example, 0.05 μm to 3 μm.

[0482] <Layer structure of the laminate> The following are examples of the layer structure of the laminates of this disclosure. In the case of the stretched film (X), the polyolefin layer below should be read as the polyethylene layer. The laminate 2 shown in Figure 2 comprises a heat seal layer 80, a first vapor-deposited film 41, an adhesive layer 60, and a barrier layer 1 in this order. Specifically, it comprises a heat seal layer 80, a first vapor-deposited film 41, an adhesive layer 60, a second vapor-deposited film 42, a surface resin layer (G) or (AH) 20 or an anchor coat layer 22, and a polyolefin layer 10 in this order. The laminate 2 may further comprise a printed layer, which is not shown. The laminate 2 may further comprise a printed layer, for example, on the polyolefin layer 10 in the barrier layer 1 or on the second vapor-deposited film 42.

[0483] The laminate 2 shown in Figure 3 comprises a heat seal layer 80, a first vapor-deposited film 41, a first adhesive layer 61, a barrier layer 1, a second adhesive layer 62, and a polyolefin substrate layer 70 in this order. Specifically, it comprises a heat seal layer 80, a first vapor-deposited film 41, a first adhesive layer 61, a polyolefin layer 10, a surface resin layer (G) or (AH) 20 or an anchor coat layer 22, a second vapor-deposited film 42, a second adhesive layer 62, and a polyolefin substrate layer 70 in this order. The laminate 2 may further comprise a printed layer not shown, for example, a printed layer not shown may further comprise the surface of the polyolefin substrate layer 70 (for example, the surface on the second adhesive layer 62 side).

[0484] In Figures 2 and 3, the barrier layer 1 may further comprise a barrier coating layer (not shown) on the second vapor-deposited film 42. In Figures 2 and 3, the orientation of the barrier layer 1 may be reversed. In Figures 2 and 3, the laminate 2 may further comprise a barrier coating layer (not shown) on the first vapor-deposited film 41. In Figures 2 and 3, the adhesive layers 60, 61, and 62 may be, for example, adhesive layers or extruded resin layers.

[0485] In Figures 2 and 3, the heat seal layer 80 may comprise a polyolefin layer, an adhesive resin layer and a surface resin layer (G), or a polyolefin layer and a surface resin layer (AH). In this case, the first vapor-deposited film is provided on the surface resin layer (G) or (AH). In Figures 2 and 3, the laminate 2 may also comprise an anchor coat layer (not shown) between the heat seal layer 80 and the first vapor-deposited film 41.

[0486] <Gas barrier properties of laminates> Oxygen permeability of the laminate of the present disclosure (unit: cc / (m) 2 The oxygen permeability (day·atm) is preferably less than 3.0, more preferably less than 2.0, even more preferably less than 1.0, and particularly preferably less than 0.5, less than 0.3, or less than 0.1. The lower limit of oxygen permeability may be, for example, 0.01. Oxygen permeability is measured in accordance with JIS K7126-2:2006 at a temperature of 23°C and a humidity of 90% RH.

[0487] Water vapor permeability of the laminate of this disclosure (unit: g / (m³) 2 The water vapor transmission rate (day) is preferably less than 3.0, more preferably less than 2.0, even more preferably less than 1.0, and particularly preferably less than 0.5, less than 0.3, or less than 0.1. The lower limit of the water vapor transmission rate may be, for example, 0.01 or 0.05. The water vapor transmission rate is measured in accordance with JIS K7129-2:2019 under conditions of 40°C and 90% RH humidity.

[0488] [Packaging container] The laminates of this disclosure can be suitably used for packaging material applications. The packaging material is used to manufacture packaging containers. By using at least the laminates of this disclosure, packaging containers with excellent gas barrier properties can be manufactured.

[0489] Examples of packaging containers include packaging bags, tube containers, and containers with lids.

[0490] Examples of packaging bags include various types such as standing pouches, side-sealed bags, two-sided sealed bags, three-sided sealed bags, four-sided sealed bags, envelope-type sealed bags, gusseted sealed bags (pillow seal type), pleated sealed bags, flat-bottom sealed bags, square-bottom sealed bags, and gusseted bags. Packaging bags may also be small bags or resealable bags. Packaging bags may be refill pouches that contain contents such as liquids and powders that can be transferred into containers such as bottles, and may be particularly standing pouches. Packaging bags may also be flexible bags.

[0491] The packaging container of this disclosure comprises the laminate of this disclosure. The packaging containers of this disclosure are, for example, One or more laminates of this disclosure, The seal portion where the heat seal layers of the above laminate are joined together, A compartment for storing contents, It has. The sealing portion includes an inner edge that defines the housing portion.

[0492] Methods for forming a seal include, for example, heat sealing, which involves melting the heat seal layers of a laminate by heating and fusing the heat seal layers together. Specifically, these include bar seals, rotary roll seals, belt seals, impulse seals, high-frequency seals, and ultrasonic seals. For example, after placing contents in a packaging bag, the opening of the packaging bag can be sealed by heat sealing.

[0493] The packaging bag may be equipped with an easy-open section. Examples of easy-open sections include a notch that serves as the starting point for tearing the packaging bag, and a half-cut line formed by laser processing or a cutter as a path when tearing the packaging bag.

[0494] In one embodiment, the laminate of the present disclosure is used as a lid material in a container with a lid. The container with a lid 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-sealed layer of the laminate, and the container body are heat-sealed. Examples of container body shapes include cup shape and bottomed cylindrical shape. The container body is made of, for example, polystyrene, polypropylene, polyethylene, or paper.

[0495] Examples of contents contained in packaging containers include liquids, solids, powders, and gels. The contents may be food and beverages, or non-food and beverages such as chemicals, cosmetics, pharmaceuticals, metal parts, and electronic components. Examples of contents include shampoo, rinse, conditioner, hand soap, body soap, fragrances, deodorants, odor removers, insect repellents, fabric softeners, detergents; sauces, soy sauce, dressings, cooking oils, mayonnaise, ketchup, syrups, cooking alcoholic beverages, and other liquid or viscous condiments; fruit juices; spices; liquid beverages, jelly beverages, liquid soups, powdered soups, instant foods, and other food and beverages; creams; toothpaste; metal parts, and electronic components.

[0496] In one embodiment, a packaging bag can be made by folding the laminate of the present disclosure in half and overlapping the layers, for example, with the barrier layer on the outside and the heat-seal layer on the inside, and then heat-sealing the edges. In another embodiment, a packaging bag can be made by overlapping multiple laminates of the present disclosure so that the heat-seal layers face each other, and then heat-sealing the edges. The entire packaging bag may be made of the above-mentioned laminate, or only a part of the packaging bag may be made of the above-mentioned laminate.

[0497] In one embodiment, the standing pouch comprises a body made of side sheets and a bottom made of a bottom sheet. The bottom sheet maintains the shape of the side sheets, thereby giving the pouch self-supporting properties and enabling it to be a standing pouch. A storage compartment for containing contents is formed within the area enclosed by the side sheets and the bottom sheet. In the standing pouch, only the side sheets may be the laminate of the disclosure, only the bottom sheet may be the laminate of the disclosure, or both the side sheets and the bottom sheet may be the laminate of the disclosure.

[0498] In one embodiment, the side sheet can be formed by manufacturing a bag such that the heat-seal layer of the laminate of the present disclosure is the innermost layer. In one embodiment, the side sheet can be formed by preparing two laminates of the present disclosure, overlapping them so that the heat-seal layers face each other, and heat-sealing the side edges on both sides to form a bag.

[0499] In another embodiment, the side sheet can be formed by preparing two laminates of the present disclosure, stacking them so that the heat-seal layers face each other, and inserting two V-shaped folded laminates between the stacked laminates at the side edges on both sides of the stacked laminates, with the heat-seal layers facing outwards, and then heat-sealing them. According to this manufacturing method, a standing pouch having a body with side gussets can be obtained.

[0500] In one embodiment, the bottom sheet can be formed by inserting the laminate of the present disclosure between the lower parts of the bag-formed side sheets and heat sealing it. More specifically, the bottom sheet can be formed by inserting a laminate folded in a V-shape with the heat-sealed layer facing outwards between the lower parts of the bag-formed side sheets and heat sealing it.

[0501] In one embodiment, two laminates of the present disclosure are prepared and stacked so that their heat-seal layers face each other. Then, the other laminate of the present disclosure is folded into a V-shape so that its heat-seal layer faces outwards, and this is sandwiched between the bottoms of the stacked laminates and heat-sealed to form the bottom. Next, the two sides adjacent to the bottom are heat-sealed to form the body. In this way, a standing pouch of one embodiment can be formed.

[0502] [Example of an embodiment] This disclosure relates, for example, to the following [1] to

[19] . [1] A laminate comprising, in this order, a heat seal layer, a first vapor-deposited film, an adhesive layer, and a barrier layer, wherein the heat seal layer mainly contains polyolefin, and the barrier layer comprises a stretched film and a second vapor-deposited film. (1) The stretched film comprises at least a polyolefin layer containing polyolefin as the main component, and a surface resin layer containing a gas barrier resin as the main component, or a polyolefin and an adhesive resin, and the second vapor-deposited film is provided on the surface resin layer, or (2) The stretched film is a polyolefin-based stretched film, and an anchor coat layer containing a resin material having polar groups is provided between the stretched film and the second vapor-deposited film. Laminated structure. [2] The laminate according to [1], wherein the surface resin layer is a layer mainly containing a gas barrier resin, and the surface resin layer contains at least one selected from the group consisting of ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and polyamide as the gas barrier resin, or the surface resin layer is a layer containing a polyolefin and an adhesive resin, and the content of the polyolefin 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. [3] The laminate according to [1] or [2], wherein the stretched film comprises a first surface resin layer containing polyolefin as the main component and a polyolefin intermediate layer containing polyolefin as the main component, and the surface resin layer containing a gas barrier resin as the main component or polyolefin and an adhesive resin is the second surface resin layer of the stretched film, provided that if the resin compositions of adjacent layers constituting the stretched film are the same and indistinguishable from each other, the adjacent layers may be integrated to form a single layer. [4] The laminate according to any one of [1] to [3], wherein the polyolefin in the stretched film is polyethylene, and the stretched film is a uniaxially oriented film. [5] The laminate according to any one of [1] to [3], wherein the stretched film is a biaxially oriented film. [6] The stretched film is A polyethylene-based stretched film wherein the polyolefin layer contains polyethylene as the main component, and the surface resin layer contains a gas barrier resin as the main component. A polypropylene-based stretched film wherein the polyolefin layer contains polypropylene as the main component, and the surface resin layer contains a gas barrier resin as the main component, The polyolefin layer contains polyethylene as the main component, and the surface resin layer contains polyethylene and an adhesive resin, or A polypropylene-based stretched film in which the polyolefin layer contains polypropylene as the main component and the surface resin layer contains polypropylene and an adhesive resin. The laminate described in [5] above. [7] The laminate according to any one of [1] to [6], wherein the resin material contained in the anchor coat layer is at least one selected from the group consisting of hydroxyl group-containing (meth)acrylic resin, hydroxyl group-free (meth)acrylic resin, urethane resin, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyester, polyamide, and polyethyleneimine. [8] The laminate according to any one of [1] to [7], wherein the ratio of the thickness of the anchor coat layer to the total thickness of the stretched film and the anchor coat layer is 0.08% or more and 20% or less. [9] The laminate according to any one of [1] to [8], wherein each layer in the laminate is arranged in the order of the heat seal layer, the first vapor-deposited film, the adhesive layer, the stretched film, and the second vapor-deposited film, or the heat seal layer, the first vapor-deposited film, the adhesive layer, the second vapor-deposited film, and the stretched film.

[10] The laminate according to any one of [1] to [9], wherein the laminate further comprises a polyolefin substrate layer on the barrier layer, an adhesive layer is provided between the barrier layer and the polyolefin substrate layer, and the polyolefin substrate layer contains polyolefin as the main component.

[11] The laminate according to

[10] , wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer are each independently an adhesive layer or an extruded resin layer.

[12] The laminate according to

[11] , wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer, are each independently adhesive layers composed of a solvent-type or solvent-free adhesive.

[13] The laminate according to

[11] , wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer are each independently extruded resin layers containing polyethylene as the main component.

[14] The laminate according to

[11] , wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer are each independently extruded resin layers containing polyolefin plastomer and acid group-containing polyethylene.

[15] The laminate according to any one of [1] to

[14] , wherein the content of polyolefin in the entire laminate is 80% by mass or more.

[16] The heat seal layer comprises a surface resin layer containing a gas barrier resin as the main component, or a surface resin layer containing polyolefin and an adhesive resin, a first HS layer containing linear low-density polyethylene as the main component, a second HS layer containing linear low-density polyethylene as the main component, and a density of 0.920 g / cm³ 3 A laminate according to any one of [1] to

[15] , comprising, in this order, a third HS layer containing linear low-density polyethylene or ultra-low-density polyethylene as a main component, wherein the first vapor-deposited film is provided on the surface resin layer.

[17] The heat seal layer comprises a first HS layer mainly composed of linear low-density polyethylene, a second HS layer mainly composed of linear low-density polyethylene, and a density of 0.920 g / cm³ 3 The laminate according to any one of [1] to

[16] , comprising, in this order, a third HS layer mainly containing linear low-density polyethylene or ultra-low-density polyethylene, wherein the laminate further comprises an anchor coat layer containing a resin material having polar groups between the first HS layer and the first vapor-deposited film, and the first vapor-deposited film is provided on the anchor coat layer.

[18] A packaging container having a laminate according to any of [1] to

[17] above, a seal portion in which the heat seal layers of the laminate are joined together, and a storage portion for storing contents.

[19] The packaging container described in

[18] above, which is a packaging bag. [Examples]

[0503] The laminates of this disclosure will be described in more detail below with reference to examples, but the laminates of this disclosure are not limited to the following examples. In the following description, "mass parts" will be simply referred to as "parts".

[0504] [Material A for stretched film] The following materials were used in the production of the stretched film. • Ethylene-vinyl alcohol copolymer (EVOH) Made by Kuraray, EVAL E171B, Density: 1.14g / cm3 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 • Crystalline semi-aromatic polyamide (semi-aromatic PA) Mitsubishi Gas Chemical Co., Ltd., 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) EMS Corporation, Grivory G21, Polyamide 6I / 6T (PA6I / 6T), Glass transition temperature: 125°C, MVR: 25cm 3 / 10 minutes • Acid-modified linear low-density polyethylene (MAH-LLDPE) Arkema OREVAC 18302N, Maleic anhydride graft-modified linear low-density polyethylene, Density: 0.912g / cm 3 Melting point: 123℃, MFR: 1.5g / 10min • Linear low-density polyethylene (LLDPE) ExxonMobil Exceed XP8656ML, Ethylene-1-hexene copolymer, density: 0.916 g / cm³ 3 , Melting point: 121℃, MFR: 0.5g / 10min • Linear low-density polyethylene (LLDPE) ExxonMobil Exceed 1327MD, Ethylene-1-hexene copolymer, density: 0.927 g / cm³ 3 , Melting point: 123℃, MFR: 1.3g / 10min Medium-density polyethylene (MDPE) ExxonMobil, Enable 4002MC, Density: 0.938g / cm 3 Melting point: 128℃, MFR: 0.25g / 10min Medium-density polyethylene (MDPE) Dow Chemical ELITE 5538G, Density: 0.941g / cm 3 Melting point: 129℃, MFR: 1.3g / 10min ·Adhesive resin Mitsui Chemicals, Admar AT1955E, Maleic anhydride graft-modified polyethylene, Density: 0.890g / cm 3 MFR: 2.6g / 10 minutes

[0505] [Manufacturing example 1A] Blended polyethylene (A) was prepared by mixing 60 parts of LLDPE (Exceed XP8656ML) and 40 parts of MDPE (Enable 4002MC). Blended polyethylene (B) was prepared by mixing 70 parts of MDPE (Enable 4002MC) and 30 parts of LLDPE (Exceed 1327MD).

[0506] Blended polyethylene (B) and, Blended polyethylene (A) and LLDPE (Exceed XP8656ML) and, Adhesive resin (Admer AT1955E) and, EVOH (Eval E171B) and, The material was extruded from the extruder through a multilayer annular die using a 5-layer co-extrusion inflation apparatus to form a tube shape, and the extruded material was inflated with air pressure while being pulled vertically to form a tubular film. The tubular film comprises an EVOH layer forming the outer surface of the tube, an adhesive resin layer, an LLDPE layer, a blended polyethylene (A) layer, and a blended polyethylene (B) layer forming the inner surface of the tube. After flattening the tubular film by joining its inner surfaces together, both ends in the width direction of the tubular film were cut to a predetermined width to separate it into two films. Each of the obtained films was stretched four times in the machine direction (MD direction) using a stretching device to produce a stretched film (uniaxially oriented film) with a thickness of 25 μm.

[0507] The stretched film obtained in this manner 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).

[0508] Water, isopropyl alcohol, and a small amount of hydrochloric acid were mixed, and tetraethoxysilane and a small amount of 3-glycidoxypropyltriethoxysilane were added while cooling. A solution obtained by mixing polyvinyl alcohol, water, and isopropyl alcohol was added to the resulting solution. In this way, a barrier coating agent was obtained.

[0509] Three types of barrier films were prepared as follows. A 70 nm thick aluminum (AL) vapor-deposited film was formed on the second surface resin layer of the stretched film by PVD (Physical Vapor Deposition). In this way, a barrier film 1 was obtained. A 30 nm thick alumina vapor-deposited film was formed on the second surface resin layer of the stretched film by PVD. The barrier coating agent was coated onto the surface of the alumina vapor-deposited film by spin coating, 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. Barrier film 2 was obtained in this manner. Barrier film 3 was obtained in the same manner as barrier film 2, except that a silica vapor-deposited film was formed instead of the alumina vapor-deposited film.

[0510] [Manufacturing examples 2A to 6A] Blended polyamide (A) was prepared by mixing 50 parts PA6 (ULTRAMID B40) and 50 parts MXD6 (MX Nylon S6007). Blended polyamide (B) was prepared by mixing 50 parts crystalline semi-aromatic PA (MXD6; MX Nylon S6007) and 50 parts amorphous semi-aromatic PA (Grivory G21). A stretched film and three types of barrier films were prepared in the same manner as in Production Example 1A, except that the resin material constituting the second surface resin layer was changed to PA6 (ULTRAMID B40), MXD6 (MX Nylon S6007), blended polyamide (A), blended polyamide (B), or amorphous semi-aromatic PA (Grivory G21), as shown in the table below. In this specification, "←" in the table means that the composition of the layer is the same as the composition in the left column, or that the thickness is the same as the thickness in the left column.

[0511] [Manufacturing example 7A] Blended polyethylene (C) was prepared by mixing 90 parts of LLDPE (Exceed XP8656ML) and 10 parts of acid-modified LLDPE (OREVAC 18302N).

[0512] Blended polyethylene (B) and, Blended polyethylene (A) and LLDPE (Exceed XP8656ML) and, Blended polyethylene (A) and Blended polyethylene (C) and The material was extruded from the extruder through a multilayer annular die using a 5-layer co-extrusion inflation apparatus to form a tube shape, and the extruded material was inflated with air pressure while being pulled vertically to form a tubular film. The tubular film comprises a blended polyethylene (C) layer, a blended polyethylene (A) layer, an LLDPE layer, another blended polyethylene (A) layer, and a blended polyethylene (B) layer forming the inner surface of the tube. After flattening the tubular film by joining its inner surfaces together, both ends in the width direction of the tubular film were cut to a predetermined width to separate it into two films. Each of the obtained films was stretched four times in the machine direction (MD direction) using a stretching device to produce a stretched film (uniaxially oriented film) with a thickness of 25 μm.

[0513] The stretched film thus obtained comprises, in this order, a 3 μm thick blended polyethylene (B) layer (first polyethylene layer, first surface resin layer), a 4 μm thick blended polyethylene (A) layer (second polyethylene layer), an 11 μm thick LLDPE layer (third polyethylene layer), a 4 μm thick blended polyethylene (A) layer (fourth polyethylene layer), and a 3 μm thick blended polyethylene (C) layer (second surface resin layer). Three types of barrier films were prepared in the same manner as in Production Example 1A, except that this stretched film was used.

[0514] [Comparative manufacturing example 1A] A single-layer film was obtained by single-layer extrusion of MDPE (ELITE 5538G) using the inflation method. This film was stretched four times in the mechanical direction (MD direction) using a stretching device to produce a stretched film (uniaxially oriented film) with a thickness of 25 μm. Three types of barrier films were prepared in the same manner as in Production Example 1A, except that this stretched film was used.

[0515] [Material B for stretched film] The following materials were used in the production of the stretched film. • Ethylene-vinyl alcohol copolymer (EVOH) Kuraray-made, EVAL G156B, melting point: 157℃, MFR: 6.4g / 10min Ethylene content: 48 mol% • Aliphatic polyamide (aliphatic PA) Made by UBE, polyamide 6 (PA6) 1020, Melting point: 220°C, relative viscosity: 3.04 • Crystalline semi-aromatic polyamide (semi-aromatic PA) Mitsubishi Gas Chemical Co., Ltd., 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) EMS Corporation, Grivory G21, Polyamide 6I / 6T (PA6I / 6T), Glass transition temperature: 125°C, MVR: 25cm 3 / 10 minutes • Adhesive resin (acid-modified LLDPE) Mitsui Chemicals, Admar NF587, Maleic anhydride graft-modified linear low-density polyethylene, Density: 0.910g / cm 3 Melting point: 120℃, MFR: 2.3g / 10min • Adhesive resin (acid-modified r-PP) Mitsui Chemicals, Admar QF580, Maleic anhydride graft-modified random polypropylene, Density: 0.900g / cm 3 Melting point: 140℃, MFR: 7.7g / 10min • Linear low-density polyethylene (LLDPE) INNATE TF80, manufactured by Dow Chemical. Metallocene LLDPE, ethylene-1-octene copolymer, Density: 0.926g / cm 3 MFR: 1.7g / 10 minutes • Homopolypropylene (h-PP) Manufactured by The Polyolefin Company (Singapore) COSMOPLENE FS3031, density: 0.900g / cm 3 , Melting point: 168℃, MFR: 3.4g / 10min Isotactic Index: 98% Random polypropylene (r-PP) Manufactured by The Polyolefin Company (Singapore) COSMOPLENE FS5612, density: 0.900g / cm 3 , Melting point: 134℃, MFR: 5.5g / 10min • Acid-modified linear low-density polyethylene (MAH-LLDPE) Arkema OREVAC 18302N, Maleic anhydride graft-modified linear low-density polyethylene, Density: 0.912g / cm 3 Melting point: 123℃, MFR: 1.5g / 10min • Acid-modified random polypropylene (MAH-r-PP) Made by Arkema, OREVAC 18722. Maleic anhydride graft-modified random polypropylene, Density: 0.900g / cm 3 Melting point: 143℃, MFR: 7.0g / 10min

[0516] [Preparation of composition] Blended polyethylene (D) was prepared by mixing 90 parts of LLDPE (INNATE TF80) and 10 parts of acid-modified LLDPE (OREVAC 18302N). Blended polypropylene (A) was prepared by mixing 80 parts homopolypropylene (FS3031) and 20 parts random polypropylene (FS5612). Blended polypropylene (B) was prepared by mixing 90 parts of random polypropylene (FS5612) and 10 parts of acid-modified random polypropylene (OREVAC 18722). Blended polyamide (C) was prepared by mixing 50 parts of aromatic polyamide (MXD6) and 50 parts of aliphatic polyamide (Polyamide 6 1020). Blended polyamide (D) 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).

[0517] [Manufacturing example 1B] LLDPE (INNATE TF80) and, LLDPE (INNATE TF80) and, LLDPE (INNATE TF80) and, Adhesive resin (Admer NF587), EVOH (Eval G156B) and, A five-layer film was obtained by co-extruding five layers of material using the T-die-casting method. This film was then subjected to sequential biaxial stretching, stretching five times in the mechanical direction (MD direction) followed by 8.5 times in the width direction (TD direction), to produce a stretched film (biaxially oriented film) with a thickness of 25 μm.

[0518] The stretched film thus obtained comprises, in this order, a 1 μm thick LLDPE layer (first polyethylene layer, first surface resin layer), a 2 μm thick LLDPE layer (second polyethylene layer), a 19 μm thick LLDPE layer (third polyethylene layer), a 2 μm thick adhesive resin layer, and a 1 μm thick EVOH layer (second surface resin layer). Three types of barrier films were prepared in the same manner as in Production Example 1A, except that the stretched film was used.

[0519] [Manufacturing examples 2B to 6B] A stretched film and three types of barrier films were prepared in the same manner as in Production Example 1B, except that the resin material constituting the second surface resin layer was changed to aliphatic polyamide (Polyamide 6 1020), aromatic polyamide (MXD6), blended polyamide (C), blended polyamide (D), or amorphous semi-aromatic PA (Grivory G21), as shown in the table below.

[0520] [Manufacturing example 7B] LLDPE (INNATE TF80) and, LLDPE (INNATE TF80) and, LLDPE (INNATE TF80) and, LLDPE (INNATE TF80) and, Blended polyethylene (D) and, A five-layer film was obtained by co-extruding five layers of material using the T-die-casting method. This film was then subjected to sequential biaxial stretching, stretching five times in the mechanical direction (MD direction) followed by 8.5 times in the width direction (TD direction) to produce a stretched film (biaxially oriented film) with a thickness of 25 μm. Three types of barrier films were produced in the same manner as in Production Example 1A, except that this stretched film was used.

[0521] [Manufacturing example 8B] Blended polypropylene (A) and Homopolypropylene (FS3031) and, Homopolypropylene (FS3031) and, Adhesive resin (Admer QF580), EVOH (Eval G156B) and, A five-layer film was obtained by co-extruding five layers of material using the T-die-casting method. This film was then subjected to sequential biaxial stretching,...

Claims

1. Heat seal layer and The first vapor-deposited film and Adhesive layer and Barrier layer, A laminate comprising at least the following in this order: The heat seal layer contains polyolefin as its main component, The barrier layer comprises a stretched film and a second vapor-deposited film. (1) The stretched film comprises at least a polyolefin layer containing polyolefin as the main component, and a surface resin layer containing a gas barrier resin as the main component, or a polyolefin and an adhesive resin, and the second vapor-deposited film is provided on the surface resin layer, or (2) The stretched film is a polyolefin-based stretched film, and an anchor coat layer containing a resin material having polar groups is provided between the stretched film and the second vapor-deposited film. Laminated structure.

2. The surface resin layer is a layer containing a gas barrier resin as its main component, and the surface resin layer contains at least one selected from the group consisting of ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and polyamide as the gas barrier resin, or The surface resin layer is a layer containing a polyolefin and an adhesive resin, wherein the content of the polyolefin 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 laminate according to claim 1.

3. The laminate according to claim 1, wherein the stretched film comprises a first surface resin layer containing polyolefin as the main component and a polyolefin intermediate layer containing polyolefin as the main component, and the surface resin layer containing a gas barrier resin as the main component or polyolefin and an adhesive resin is the second surface resin layer of the stretched film, provided that if the resin compositions of adjacent layers constituting the stretched film are the same and indistinguishable from each other, the adjacent layers may be integrated to form a single layer.

4. The laminate according to claim 1, wherein the polyolefin in the stretched film is polyethylene, and the stretched film is a uniaxially oriented film.

5. The laminate according to claim 1, wherein the stretched film is a biaxially oriented film.

6. The stretched film is A polyethylene-based stretched film wherein the polyolefin layer contains polyethylene as the main component, and the surface resin layer contains a gas barrier resin as the main component, A polypropylene-based stretched film wherein the polyolefin layer contains polypropylene as the main component, and the surface resin layer contains a gas barrier resin as the main component. A polyethylene-based stretched film in which the polyolefin layer contains polyethylene as the main component, and the surface resin layer contains polyethylene and an adhesive resin, or A polypropylene-based stretched film in which the polyolefin layer contains polypropylene as the main component and the surface resin layer contains polypropylene and an adhesive resin. The laminate according to claim 5.

7. The laminate according to claim 1, wherein the resin material contained in the anchor coat layer is at least one selected from the group consisting of hydroxyl group-containing (meth)acrylic resin, hydroxyl group-free (meth)acrylic resin, urethane resin, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyester, polyamide, and polyethyleneimine.

8. The laminate according to claim 1, wherein the ratio of the thickness of the anchor coat layer to the total thickness of the stretched film and the anchor coat layer is 0.08% or more and 20% or less.

9. The laminate according to claim 1, wherein each layer in the laminate is arranged in the order of the heat seal layer, the first vapor-deposited film, the adhesive layer, the stretched film, and the second vapor-deposited film, or the heat seal layer, the first vapor-deposited film, the adhesive layer, the second vapor-deposited film, and the stretched film.

10. The laminate further comprises a polyolefin substrate layer on the barrier layer, An adhesive layer is provided between the barrier layer and the polyolefin substrate layer. The aforementioned polyolefin substrate layer contains polyolefin as its main component. The laminate according to claim 1.

11. The laminate according to claim 10, wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer are each independently an adhesive layer or an extruded resin layer.

12. The laminate according to claim 11, wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer, are each independently adhesive layers composed of a solvent-type or solvent-free adhesive.

13. The laminate according to claim 11, wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer are each independently extruded resin layers containing polyethylene as the main component.

14. The laminate according to claim 11, wherein the adhesive layer between the first vapor-deposited film and the barrier layer, and the adhesive layer between the barrier layer and the polyolefin substrate layer, are each independently extruded resin layers containing polyolefin plastomer and acid group-containing polyethylene.

15. The laminate according to claim 1, wherein the polyolefin content in the entire laminate is 80% by mass or more.

16. The heat seal layer comprises a surface resin layer containing a gas barrier resin as the main component, or a surface resin layer containing polyolefin and adhesive resin, a first HS layer containing linear low-density polyethylene as the main component, a second HS layer containing linear low-density polyethylene as the main component, and a density of 0.920 g / cm³. 3 The following are provided in this order: a third HS layer containing linear low-density polyethylene or ultra-low-density polyethylene as the main component, The first vapor-deposited film is provided on the surface resin layer. The laminate according to claim 1.

17. The heat seal layer comprises a first HS layer mainly composed of linear low-density polyethylene, a second HS layer mainly composed of linear low-density polyethylene, and a density of 0.920 g / cm³. 3 The following are provided in this order: a third HS layer containing linear low-density polyethylene or ultra-low-density polyethylene as the main component, The laminate further comprises an anchor coat layer containing a resin material having polar groups between the first HS layer and the first vapor-deposited film, and the first vapor-deposited film is provided on the anchor coat layer. The laminate according to claim 1.

18. A laminate according to any one of claims 1 to 17, The seal portion where the heat seal layers of the laminate are joined together, A compartment for storing contents, A packaging container having

19. A packaging container according to claim 18, which is a packaging bag.

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