JP2024112680A - Laminate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film which has a polyolefin resin layer and is excellent in gas barrier property.

SOLUTION: A laminate film includes a polyolefin resin layer, an adhesive resin layer, and a gas barrier resin layer in this order, wherein the adhesive resin layer contains an acid-modified resin as a main component, and the gas barrier resin layer contains at least one resin selected from an ethylene-vinyl alcohol copolymer and polyamide.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

This disclosure relates to a laminated film.

Conventionally, resin films made of resin materials have been used as packaging materials. For example, resin films made of polyolefins have appropriate flexibility and transparency and are therefore used as base materials or sealant films that constitute packaging materials (for example, Patent Document 1).

JP 2009-202519 A

The present inventors have investigated the use of a laminate having a polyolefin film as a packaging material to produce a packaging container. However, such packaging containers tend to have insufficient gas barrier properties. The present inventors have therefore investigated the provision of a vapor deposition film on the polyolefin film. However, even with this configuration, the gas barrier properties are still insufficient.

One of the problems to be solved by this disclosure is to provide a laminated film that has a polyolefin resin layer and has excellent gas barrier properties.

The laminated film of the present disclosure comprises, in this order, a polyolefin resin layer, an adhesive resin layer, and a gas barrier resin layer, the adhesive resin layer containing an acid-modified resin as a main component, and the gas barrier resin layer containing at least one resin selected from an ethylene-vinyl alcohol copolymer and a polyamide.

According to the present disclosure, it is possible to provide a laminate film having a polyolefin resin layer and excellent gas barrier properties.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a laminated film. FIG. 2 is a schematic cross-sectional view showing one embodiment of a laminated film. FIG. 3 is a schematic cross-sectional view showing one embodiment of a laminated film. FIG. 4 is a schematic cross-sectional view showing one embodiment of the laminated film. FIG. 5 is a schematic cross-sectional view showing one embodiment of a laminate. FIG. 6 is a schematic cross-sectional view showing one embodiment of a laminate. FIG. 7 is a schematic cross-sectional view showing one embodiment of a laminate. FIG. 8 is a perspective view showing one embodiment of a packaging bag. FIG. 9 is a perspective view showing one embodiment of a packaging bag.

In this specification, when multiple upper limit candidates and multiple lower limit candidates are given for a certain parameter, the numerical range of the parameter may be formed by combining any one of the upper limit candidates and any one of the lower limit candidates. As an example, the description "Parameter B is preferably A1 or more, more preferably A2 or more, even more preferably A3 or more, and preferably A4 or less, more preferably A5 or less, and even more preferably A6 or less." will be explained. In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

The following describes in detail the embodiments of the present disclosure. The present disclosure can be implemented in many different forms, and is not to be construed as being limited to the description of the embodiments exemplified below. In the drawings, the width, thickness, shape, etc. of each layer may be shown diagrammatically compared to the embodiments in order to make the explanation clearer, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those already explained with respect to the previous figures are given the same reference numerals, and detailed explanations may be omitted as appropriate.

Each of the components appearing in the following description (e.g., polyolefins such as polyethylene and polypropylene, α-olefins, resin materials, acid-modified resins, gas barrier resins, additives, metals, and inorganic oxides) may be used alone or in combination of two or more types.

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

[Laminated film]
The laminate film of the present disclosure comprises a polyolefin resin layer, an adhesive resin layer, and a gas barrier resin layer in this order in the thickness direction (hereinafter, "in this order in the thickness direction" will simply be referred to as "in this order").
The adhesive resin layer contains an acid-modified resin as a main component.
The gas barrier resin layer contains at least one resin selected from an ethylene-vinyl alcohol copolymer and a polyamide.

The laminated film is preferably an unstretched film. An unstretched film means a film that has not been intentionally stretched (a film whose molecules have not been oriented by stretching). Details of the stretching process will be described later. Films that are inevitably stretched during extrusion molding or film winding are also included in the category of unstretched film.

The laminate film of the present disclosure may further include a vapor deposition film provided on the gas barrier resin layer. That is, the laminate film may include a polyolefin resin layer, an adhesive resin layer, a gas barrier resin layer, and a vapor deposition film in this order.

The laminated film 10 shown in FIG. 1 includes a polyolefin resin layer 12, an adhesive resin layer 13, and a gas barrier resin layer 14, in this order.
The laminated film 10 shown in FIG. 2 has, as the polyolefin resin layer 12, a first resin layer 12a containing a polyolefin and a second resin layer 12b containing a polyolefin and a heat seal modifier, in this order, and the second resin layer 12b is one of the surface layers of the laminated film 10.
The laminated film 10 shown in FIG. 3 includes, as the polyolefin resin layer 12, a first resin layer 12a containing a polyolefin, a third resin layer 12c containing a polyolefin, a fourth resin layer 12d containing a polyolefin, and a second resin layer 12b containing a polyolefin and a heat seal modifier, in this order, and the second resin layer 12b is one of the surface layers of the laminated film 10.
4 includes an unstretched resin film having a polyolefin resin layer 12, an adhesive resin layer 13, and a gas barrier resin layer 14 in this order, and a vapor-deposited film 15. The vapor-deposited film 15 is provided on the gas barrier resin layer 14.

The resin film having a polyolefin resin layer, an adhesive resin layer, and a gas barrier resin layer is preferably an unstretched resin film, more preferably an unstretched coextruded resin film formed by a coextrusion T-die cast film forming method, and each layer constituting the resin film is a coextruded resin layer. In one embodiment, the resin film is a coextruded resin film of three or more layers, preferably a coextruded resin film of three to nine layers, more preferably a coextruded resin film of five to seven layers. A thin gas barrier resin layer can be formed by multilayer coextrusion. In one embodiment, the resin film is an unstretched resin film obtained by forming a material constituting the polyolefin resin layer, a material constituting the adhesive resin layer, and a material constituting the gas barrier resin layer by a coextrusion T-die cast film forming method. Such a laminated film is suitable as a sealant film, for example, from the viewpoint of heat sealability, and is also suitable as an intermediate substrate described later.

An embodiment of co-extrusion T-die casting is described below. The materials for forming each layer are fed to each extruder, extruded in fixed amounts by the gear pump of the extruder, fed to a multi-manifold die, and co-extrusion cast-molded to obtain a laminated film. For example, in each extruder, the screw temperature for the gas barrier resin is set to 230°C or higher and 240°C or lower, the screw temperature for the acid-modified resin is set to 230°C or higher and 240°C or lower, and the screw temperature for the polyolefin is set to 240°C or higher and 260°C or lower.

The polyolefin (specifically, polypropylene or polyethylene) content in the laminate film 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 80% by mass or more. Such a laminate film is preferable, for example, from the viewpoint of recyclability. The polyolefin content in the laminate film means the ratio of the polyolefin content to the sum of the resin material contents in each layer constituting the laminate film.

The thickness of the laminate film is preferably 6 μm or more, more preferably 12 μm or more, and preferably 110 μm or less, more preferably 60 μm or less. A laminate film having a thickness equal to or greater than the lower limit has, for example, excellent strength, heat sealability, and recyclability. A laminate film having a thickness equal to or less than the upper limit has, for example, excellent processability. In this specification, the thickness of the laminate film and each layer is the average value of the thickness measured at 10 points based on a scanning electron microscope (SEM) image obtained by observing a vertical cross section relative to the film surface.

<Polyolefin resin layer>
In one embodiment, the polyolefin resin layer contains polyolefin as a main component, i.e., in the range of more than 50 mass %. Examples of polyolefin include polyethylene, polypropylene, and polymethylpentene. As the polyolefin resin layer, a polyethylene resin layer and a polypropylene resin layer are preferable.

From the viewpoint of processability of the laminated film, the melt flow rate (MFR) of the polyolefin is preferably 0.5 g/10 min or more, more preferably 1 g/10 min or more, even more preferably 1.5 g/10 min or more, and still more preferably 2 g/10 min or more.
From the viewpoint of cast film formability, the MFR of the polyolefin is preferably 50 g/10 min or less, more preferably 40 g/10 min or less, even more preferably 30 g/10 min or less, still more preferably 20 g/10 min or less, and particularly preferably 10 g/10 min or less.
In the present disclosure, the MFR of a polyolefin 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 polyolefin, for example, 190°C for polyethylene and 230°C for polypropylene.

The polyolefin content in the polyolefin resin layer is preferably more than 50% by mass, for example 55% by mass or more or 60% 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 93% by mass or more.

The polyolefin resin layer may contain a resin material other than polyolefin. Examples of such resin materials include (meth)acrylic resin, vinyl resin, cellulose resin, polyamide, polyester, and ionomer resin.

The polyolefin resin layer may contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins.

In one embodiment, the polyolefin resin layer may be subjected to a surface treatment. This can improve, for example, the adhesion between the polyolefin resin layer and other layers. Examples of the surface treatment method include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and/or nitrogen gas, and glow discharge treatment; and chemical treatments such as oxidation treatment using chemicals.
An easy-adhesion layer may be provided on the surface of the polyolefin resin layer.

The laminated film may have two or more polyolefin resin layers. The number of polyolefin resin layers is preferably two or more, more preferably three or more, and is preferably seven or less, more preferably five or less.

The thickness of the polyolefin resin layer is preferably 5 μm or more, more preferably 10 μm or more, and preferably 100 μm or less, more preferably 50 μm or less. When the laminated film has two or more polyolefin resin layers, it is preferable that the total thickness of the polyolefin resin layers is in the above range. A laminated film having a polyolefin resin layer whose thickness is equal to or greater than the lower limit has, for example, excellent strength, heat resistance, and recyclability. A laminated film having a polyolefin resin layer whose thickness is equal to or less than the upper limit has, for example, excellent processability.

(Polyethylene resin layer)
In one embodiment, the polyethylene resin layer contains polyethylene as a main component, i.e., in the range of more than 50 mass%. In the present disclosure, polyethylene refers to a polymer in which the content of ethylene-derived structural units in all repeating structural units is 50 mol% or more. In this polymer, the content of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The content is measured by NMR.

The 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 2 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.

Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene, with high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene being preferred. From the viewpoint of reducing the environmental load, polyethylene derived from biomass or polyethylene that has been mechanically recycled or chemically recycled may also be used.

In the present disclosure, the density of the polyethylene is as follows:
The density of the high density polyethylene is preferably greater than 0.945 g/cm ^3. The upper limit of the density of the high density polyethylene is, for example, 0.970 g/cm ³ or 0.965 g/cm ^3. The density of the medium density polyethylene is preferably greater than 0.930 g/cm ³ and not greater than 0.945 g/cm ^3. The density of the low density polyethylene is preferably greater than 0.900 g/cm ³ and not greater than 0.930 g/cm ^3. The density of the linear low density polyethylene is preferably greater than 0.900 g/cm ³ and not greater than 0.930 g/cm ^3. The density of the very low density polyethylene is preferably not greater than 0.900 g/cm ^3. The lower limit of the density of the very low density polyethylene is, for example, 0.860 g/cm ^3. In the present disclosure, the density is measured in accordance with JIS K7112:1999 D method (density gradient tube method, 23°C).

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

From the viewpoints of strength, heat resistance, heat sealability, etc., the melting point (Tm) of the polyethylene is preferably 90°C or higher, more preferably 95°C or higher, and preferably 140°C or lower, more preferably 130°C or lower. In this disclosure, Tm is the melting peak temperature obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

Polyethylenes with different densities or branches 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 a polymerization catalyst, and carry out polymerization in one stage or in two or more stages by any of the methods of gas phase polymerization, slurry polymerization, solution polymerization, and high pressure ionic polymerization.

The polyethylene content in the polyethylene resin layer is preferably more than 50% by mass, for example 55% by mass or more or 60% 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 93% by mass or more.

The laminated film may have two or more polyethylene resin layers. The number of polyethylene resin layers is preferably two or more, more preferably three or more, and is preferably seven or less, more preferably five or less.

In one embodiment, the laminated film includes, as the polyethylene resin layer, a first resin layer containing linear low-density polyethylene and a second resin layer containing linear low-density polyethylene and a heat seal modifier (preferably a polyethylene-based plastomer) described below, in this order. Such a laminated film is suitable as a sealant film.

In one embodiment, the laminated film has, as polyethylene resin layers, a first resin layer containing linear low-density polyethylene, a third resin layer containing high-density polyethylene, a fourth resin layer containing linear low-density polyethylene, and a second resin layer containing linear low-density polyethylene and a heat seal modifier, in this order.

The first resin layer may contain linear low density polyethylene as a main component, or may contain linear low density polyethylene and low density polyethylene. The third resin layer may contain high density polyethylene as a main component, or may contain high density polyethylene and low density polyethylene. The fourth resin layer may contain linear low density polyethylene as a main component, or may contain linear low density polyethylene and low density polyethylene.

The density of the third resin layer may be higher than that of the first resin layer, the density of the fourth resin layer may be lower than that of the third resin layer, or the density of the second resin layer may be lower than that of the fourth resin layer. Such a laminated film has, for example, an excellent balance of low-temperature heat sealability, interlayer adhesion, strength, and rigidity. The density of the above layers is measured in accordance with JIS K7112:1999, Method D (density gradient tube method, 23°C).

In the above embodiment, the thickness of the first and second resin layers is, independently of each other, preferably 3% or more, more preferably 5% or more, and even more preferably 7% or more, and preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less, relative to the total thickness of the polyethylene resin layer. In the above embodiment, the thickness of the third resin layer is preferably 35% or more, more preferably 40% or more, and preferably 75% or less, and more preferably 70% or less, relative to the total thickness of the polyethylene resin layer.

In one embodiment, the laminated film includes, as the polyethylene resin layers, a fifth resin layer containing linear low-density polyethylene and a sixth resin layer containing high-density polyethylene, in this order. The fifth resin layer can contribute, for example, to improving adhesion with the adhesive resin layer. The sixth resin layer can contribute, for example, to improving the rigidity and processability of the laminated film. The laminated film may include two or more sixth resin layers. Such a laminated film has, for example, excellent rigidity and processability, and is suitable as an intermediate substrate.

The fifth resin layer may contain linear low density polyethylene as a main component, or may contain linear low density polyethylene and low density polyethylene. The sixth resin layer may contain high density polyethylene as a main component, or may contain high density polyethylene and low density polyethylene.

In the above embodiment, the thickness of the fifth resin layer is, independently of the total thickness of the polyethylene resin layer, preferably 3% or more, more preferably 5% or more, and even more preferably 7% or more, and preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less. In the above embodiment, the total thickness of the sixth resin layer is, independently of the total thickness of the polypropylene resin layer, preferably 50% or more, more preferably 60% or more, and preferably 97% or less, and more preferably 95% or less.

(Polypropylene resin layer)
In one embodiment, the polypropylene resin layer contains polypropylene as a main component, i.e., in a range of more than 50 mass %. A laminate film including the polypropylene resin layer has excellent oil resistance, for example.

The polypropylene may be any of propylene homopolymer (homopolypropylene), propylene random copolymers such as propylene-α-olefin random copolymers (random polypropylene), and propylene block copolymers such as propylene-α-olefin block copolymers (block polypropylene), or a mixture of two or more selected from these. From the viewpoint of reducing the environmental load, biomass-derived polypropylene and mechanically or chemically recycled polypropylene may be used as the polypropylene.

A propylene homopolymer is a polymer of propylene only. A propylene random copolymer is a random copolymer of propylene and an α-olefin other than propylene. A propylene block copolymer is a copolymer having a polymer block of propylene and a polymer block of an α-olefin 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.

Among polypropylenes, it is preferable to use propylene random copolymers from the viewpoint of transparency. When emphasis is placed on the rigidity and heat resistance of the packaging container, it is preferable to use propylene homopolymers. When emphasis is placed on the impact resistance of the packaging container, it is preferable to use propylene block copolymers.

The density of polypropylene is, for example, 0.88 g/cm or ^more and 0.92 g/cm ^or less. The melting point (Tm) of polypropylene is preferably 120° C. or more, more preferably 125° C. or more, and is preferably 170° C. or less, more preferably 165° C. or less, from the viewpoints of strength, heat resistance, heat sealability, and the like.

The polypropylene content in the polypropylene resin layer is preferably more than 50% by mass, for example 55% by mass or more or 60% 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 93% by mass or more.

The laminated film may have two or more polypropylene resin layers. The number of polypropylene resin layers is preferably two or more, more preferably three or more, and is preferably seven or less, more preferably five or less.

In one embodiment, the laminated film includes a first resin layer containing a propylene random copolymer as a main component as a polypropylene resin layer, and a second resin layer containing a propylene random copolymer and a heat seal modifier (preferably a polypropylene-based elastomer) described below, in that order. Such a laminated film is suitable as a sealant film.

In one embodiment, the laminated film includes, as polypropylene resin layers, a first resin layer containing a propylene random copolymer as a main component, a third resin layer containing a propylene homopolymer as a main component, a fourth resin layer containing a propylene random copolymer as a main component, and a second resin layer containing a propylene random copolymer and a heat seal modifier, in this order. The first resin layer can contribute to improving adhesion with the adhesive resin layer, for example. The third resin layer can contribute to improving the rigidity of the laminated film, for example. Such a laminated film has an excellent balance of low-temperature heat sealability, interlayer adhesion, strength, and rigidity, for example.

In one embodiment, the melting point of the third resin layer is higher than the melting point of the first resin layer, the melting point of the fourth resin layer is lower than the melting point of the third resin layer, and the melting point of the second resin layer is equal to or lower than the melting point of the fourth resin layer. The melting points of the layers are obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

In the above embodiment, the thickness of the first and second resin layers is preferably 3% or more, more preferably 5% or more, and even more preferably 7% or more, and preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less, relative to the total thickness of the polypropylene resin layer. In the above embodiment, the thickness of the third resin layer is preferably 35% or more, more preferably 40% or more, and preferably 75% or less, and more preferably 70% or less, relative to the total thickness of the polypropylene resin layer.

In one embodiment, the laminated film includes, as the polypropylene resin layer, a fifth resin layer containing a propylene random copolymer as a main component, a sixth resin layer containing a propylene homopolymer as a main component, and a seventh resin layer containing a propylene random copolymer as a main component, in this order. Such a laminated film is suitable as an intermediate substrate. The fifth and seventh resin layers can, for example, contribute to improving adhesion with the adhesive resin layer or the adhesive layer, respectively. The sixth resin layer can, for example, contribute to improving the rigidity of the laminated film. The laminated film may include two or more sixth resin layers. Such a laminated film has, for example, an excellent balance of interlayer adhesion, strength, and rigidity.

In the above embodiment, the thicknesses of the fifth and seventh resin layers are each independently preferably 3% or more, more preferably 5% or more, and even more preferably 7% or more, and preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less, relative to the total thickness of the polypropylene resin layers. In the above embodiment, the total thickness of the sixth resin layer is preferably 40% or more, more preferably 50% or more, and preferably 94% or less, and more preferably 90% or less, relative to the total thickness of the polypropylene resin layers.

(Heat seal modifier)
The polyolefin resin layer, such as the polyethylene resin layer and the polypropylene resin layer, may contain a heat seal modifier in order to improve low-temperature heat sealability. A laminated film having such a polyolefin resin layer is suitable as a sealant film. The heat seal modifier is not particularly limited as long as it is a component that is highly compatible with the polyolefin constituting the polyolefin resin layer, and examples of the heat seal modifier include olefin-based polymers with low melting points, specifically olefin-based copolymers. Ultra-low density polyethylene may also be used.

There are no particular limitations on the olefin copolymer as long as it is compatible with polyolefins and has a low melting point, and examples of such copolymers include olefin elastomers and olefin plastomers.

Examples of olefin-based elastomers include polyethylene-based elastomers such as ethylene-α-olefin copolymers, and polypropylene-based elastomers such as propylene-α-olefin copolymers. Examples of α-olefins include α-olefins having 2 to 8 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene.

From the viewpoint of improving heat sealability, the melting point (Tm) of the polypropylene-based elastomer is preferably 140°C or less, more preferably 135°C or less. The lower limit of Tm is not particularly limited, but is, for example, 70°C, 80°C, or 90°C.

A plastomer is a term used in contrast to an elastomer (a polymer that deforms in response to the application of an external force and returns to its original shape in a short time when the force is removed). It is a polymer that does not exhibit elastic deformation like an elastomer, but easily undergoes plastic deformation.

Examples of olefin-based plastomers include polyethylene-based plastomers. Polyethylene-based plastomers are polyethylenes obtained by copolymerizing ethylene and α-olefins using a single-site catalyst such as a metallocene catalyst. Examples of α-olefins are preferably α-olefins having 4 to 8 carbon atoms, such as 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene. Specific examples of polyethylene-based plastomers include ethylene-1-butene copolymers, ethylene-1-hexene copolymers, and ethylene-1-octene copolymers.

From the viewpoint of improving heat sealability, the melting point (Tm) of the polyethylene plastomer is preferably 115°C or less, more preferably 110°C or less, and even more preferably 105°C or less. The lower limit of Tm is not particularly limited, but is, for example, 50°C, 60°C, or 70°C.

The density of the olefin copolymer is preferably 0.850 g/ ^cm3 or more, more preferably 0.860 g/ ^cm3 or more, even more preferably 0.870 g/ ^cm3 or more, and is preferably 0.920 g/ ^cm3 or less, more preferably 0.915 g/ ^cm3 or less, even more preferably 0.910 g/ ^cm3 or less.

From the viewpoint of film-forming property and processability, the MFR of the olefin copolymer is preferably 0.2 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 20 g/10 min or less, more preferably 15 g/10 min or less, even more preferably 10 g/10 min or less, and particularly preferably 5 g/10 min or less. The MFR of the olefin copolymer is measured by Method A in accordance with JIS K7210-1:2014, at a temperature of 190°C and a load of 2.16 kg.

The content of the heat seal modifier in the entire polyolefin resin layer is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 7% by mass or less. This can impart, for example, suitable heat sealability to the laminated film.

In one embodiment, the laminated film includes, as the polyolefin resin layer, a first resin layer containing a polyolefin and a second resin layer containing a polyolefin and a heat seal modifier, in this order. An intermediate layer containing a polyolefin (e.g., the above-mentioned third resin layer and fourth resin layer) may be provided between the first resin layer and the second resin layer. Here, the second resin layer constitutes one of the surface layers of the laminated film. With this configuration, for example, low-temperature heat sealability and processability can be achieved at the same time. Examples and preferred examples of the polyolefin and the heat seal modifier are given above.

The polyolefin content in the first resin layer and the intermediate layer (e.g., the third resin layer and the fourth resin layer described above) 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 content of the heat seal modifier in the second resin layer is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 55% by mass or less, more preferably less than 50% by mass. If the content is equal to or greater than the lower limit, the heat sealability of the second resin layer can be improved, for example. If the content is equal to or less than the upper limit, the recyclability of the laminated film can be improved, for example. The content of the polyolefin in the second resin layer is preferably 45% by mass or more, more preferably more than 50% by mass, and preferably 90% by mass or less, more preferably 80% by mass or less.

The thickness of the first resin layer is preferably 3% or more, more preferably 5% or more, and even more preferably 7% or more, relative to the total thickness of the polyolefin resin layer, and is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less.
The thickness of the second resin layer is preferably 3% or more, more preferably 5% or more, and even more preferably 7% or more, relative to the total thickness of the polyolefin resin layer, and is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less.

<Gas Barrier Resin Layer>
The laminate film of the present disclosure includes a gas barrier resin layer. Such a laminate film has excellent gas barrier properties, such as oxygen barrier property and water vapor barrier property. In one embodiment, the gas barrier resin layer constitutes a surface layer on one side of the resin film.

The gas barrier resin layer contains at least one selected from an ethylene-vinyl alcohol copolymer and a polyamide. A gas barrier resin layer containing such a component has, for example, excellent gas barrier properties.

In one embodiment, the laminated film of the present disclosure comprises a polyolefin resin layer, an adhesive resin layer containing an acid-modified polyolefin, and a gas barrier resin layer containing an ethylene-vinyl alcohol copolymer (hereinafter also referred to as "EVOH"). The adhesive resin layer is provided to improve the interlayer adhesion of the laminated film, since the adhesion between the polyolefin resin layer and the gas barrier resin layer may not be sufficient. In one embodiment, the adhesive resin layer is in contact with the gas barrier resin layer.

The present inventors have found that when a laminated film having a gas barrier resin layer containing EVOH and an adhesive resin layer containing an acid-modified polyolefin is produced by the co-extrusion T-die cast film-forming method, aggregates may be formed, especially at both ends of the laminated film. In such a case, it is necessary to cut and discard both ends where the aggregates are formed, which is one of the factors that increases costs. It is presumed that the reason for the formation of aggregates is that the reaction between the EVOH and the acid-modified polyolefin proceeds too much between the adhesive resin layer and the gas barrier resin, resulting in the formation of gel-like bumps and streaks that are high molecular weight substances. In the case of the cast film-forming method, compared to the inflation film-forming method, the flow path length and residence time of the resin are likely to vary depending on the location, so the thermal history varies depending on the location, and the molding temperature is high, so it is thought that such aggregates are more likely to be formed. In addition, in the case of a stretched film, the thickness of the film is large during extrusion, so the above-mentioned aggregates are less likely to be formed, and a stretched film with good appearance can be obtained even if the film is thinned by performing a stretching process afterwards. In contrast, in the case of unstretched film, the thickness of the film is small during extrusion, so it is believed that the above-mentioned aggregates are easily formed. Therefore, the present inventors have focused on suppressing the reaction between EVOH and acid-modified polyolefin, and have found that, for example, by adjusting the ethylene content of EVOH and the degree of acid modification in acid-modified polypropylene within a specific range, the active sites of the above reaction can be reduced, and by adjusting the MFR of each material, the formation of aggregates can be suppressed. Note that the reasons described above are speculations and do not limit the contents of this disclosure in any way.

The laminated film obtained by the cast film-forming method is less prone to curling than the laminated film obtained by the inflation film-forming method. This is presumably due to the following reasons. In the case of a laminated film having a polyolefin resin layer, an adhesive resin layer, and a gas barrier resin layer in this order, the degree and speed of crystallization of the polyolefin resin are different from the degree and speed of crystallization of the gas barrier resin. In the inflation film-forming method, cooling after film-forming is usually performed by air cooling, so cooling is performed slowly, and therefore crystallization is likely to proceed sufficiently. If the crystallization of the polyolefin resin proceeds sufficiently, the polyolefin resin layer will shrink in volume, and curling will tend to occur. In contrast, in the cast film-forming method, cooling after film-forming is usually performed by contact with a cooling roll, so cooling is performed quickly, and therefore crystallization does not proceed very much. Therefore, the volumetric shrinkage of the polyolefin resin layer is suppressed, and curling is less likely to occur.

When a laminate film is used as the sealant layer constituting the packaging material, the laminate film obtained by the cast film-forming method can be heat-sealed at a lower temperature than the laminate film obtained by the inflation film-forming method. This is presumably due to the following reasons. As described above, in the case of a laminate film obtained by the inflation film-forming method, the crystallinity of the polyolefin resin layer is high, so more heat energy is required during heat sealing, and the sealing temperature is high. In contrast, in the case of a laminate film obtained by the cast film-forming method, the crystallinity of the polyolefin resin layer is low, so the sealing temperature can be lowered during heat sealing. For example, in mono-material materials (single-system materials), it may be important that they can be heat-sealed at a low temperature.

In the ethylene-vinyl alcohol copolymer (EVOH), the content of structural units derived from ethylene (ethylene content) is preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 38 mol% or more, and particularly preferably 40 mol% or more. EVOH having an ethylene content equal to or higher than the lower limit has, for example, fewer groups (OH groups) that can react with an acid-modified resin, and therefore tends to be able to suppress the above-mentioned reaction from proceeding too far.
The ethylene content in EVOH is preferably 60 mol % or less, more preferably 50 mol % or less. EVOH having an ethylene content of the upper limit or less can improve the oxygen barrier property and water vapor barrier property of a laminate film, for example.
The ethylene content is measured by an NMR method.

The average degree of saponification of 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 (wherein EVOH is used as a solution uniformly dissolved in a water/methanol solvent).

The melting point (Tm) of EVOH is preferably 130°C or higher, more preferably 140°C or higher, even more preferably 150°C or higher, and preferably 200°C or lower, more preferably 195°C or lower, even more preferably 190°C or lower.

From the viewpoint of cast film-forming properties and processability, the melt flow rate (MFR) of EVOH is preferably 0.1 g/10 min or more, more preferably 0.3 g/10 min or more, even more preferably 0.5 g/10 min or more, and 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, and particularly preferably 5 g/10 min or less. The MFR of EVOH is measured by Method A in accordance with JIS K7210-1:2014 under conditions of a temperature of 190°C and a load of 2.16 kg, but the measurement temperature may be 210°C depending on the melting point of EVOH.

Examples of polyamides include aliphatic polyamides and semi-aromatic polyamides. As polyamides, aliphatic polyamides are preferred, and crystalline aliphatic polyamides are more preferred. As aliphatic polyamides, examples of the polyamides include aliphatic homopolyamides and aliphatic copolymer polyamides. In the following examples, polyamide is also referred to as "PA."

Specific examples of aliphatic homopolyamides include polycaprolactam (PA6), polyenantholactam (PA7), polyundecane lactam (PA11), polylauryllactam (PA12), polyhexamethylene adipamide (PA66), polytetramethylene dodecamide (PA412), polypentamethylene azelamide (PA59), polypentamethylene sebacamide (PA510), polypentamethylene dodecamide (PA512), polyhexamethylene azelamide (PA69), polyhexamethylene sebacamide (PA610), polyhexamethylene dodecamide (PA612), poly Examples include nonamethylene adipamide (PA96), polynonamethylene azelamide (PA99), polynonamethylene sebacamide (PA910), polynonamethylene dodecamide (PA912), polydecamethylene adipamide (PA106), polydecamethylene azelamide (PA109), polydecamethylene decamamide (PA1010), polydecamethylene dodecamide (PA1012), polydodecamethylene adipamide (PA126), polydodecamethylene azelamide (PA129), polydodecamethylene sebacamide (PA1210) and polydodecamethylene dodecamide (PA1212).

Specific examples of aliphatic copolymer polyamides include caprolactam/hexamethylenediaminoadipic acid copolymer (PA6/66), caprolactam/hexamethylenediaminoazelaic acid copolymer (PA6/69), caprolactam/hexamethylenediaminosebacic acid copolymer (PA6/610), caprolactam/hexamethylenediaminoundecanoic acid copolymer (PA6/611), caprolactam/hexamethylenediaminododecanoic acid copolymer (PA6/612), caprolactam/amino- Examples of such copolymers include caprolactam/hexamethylenediaminoadipic acid/hexamethylenediaminosebacic acid copolymer (PA6/66/610), caprolactam/hexamethylenediaminoadipic acid/hexamethylenediaminododecanedicarboxylic acid copolymer (PA6/66/612), caprolactam/hexamethylenediaminoadipic acid/hexamethylenediaminododecanedicarboxylic acid copolymer (PA6/66/612).

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

In one embodiment, the gas barrier resin layer contains a crystalline aliphatic polyamide. Examples of the crystalline aliphatic polyamide include PA6, PA11, PA12, PA66, PA610, PA612, PA6/66, and PA6/66/12.

The melting point (Tm) of the crystalline aliphatic polyamide is preferably 180°C or higher, more preferably 185°C or higher, even more preferably 190°C or higher, and preferably 300°C or lower, more preferably 250°C or lower, even more preferably 230°C or lower.

The gas barrier resin layer is, for example, a layer containing an ethylene-vinyl alcohol copolymer as a main component, a layer containing a polyamide as a main component, or a layer containing a mixed resin of an ethylene-vinyl alcohol copolymer and a polyamide as a main component.

The content of the gas barrier resin in the gas barrier resin layer is preferably 50% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, 85% by mass or more, or 90% by mass or more. A laminate film having such a gas barrier resin layer has, for example, excellent gas barrier properties.

The gas barrier resin layer may contain the above additives.

The thickness of the gas barrier resin layer is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 10 μm or less, more preferably 5 μm or less. A laminate film having a gas barrier resin layer whose thickness is equal to or greater than the lower limit has, for example, excellent gas barrier properties. A laminate film having a gas barrier resin layer whose thickness is equal to or less than the upper limit has, for example, excellent recyclability.

When a gas barrier resin layer containing EVOH is located on the outermost surface of a coextruded resin film, the gas barrier resin layer is susceptible to heat during coextrusion, and the above-mentioned aggregates may form. By making the gas barrier resin layer thicker, the formation of such aggregates tends to be suppressed. However, from the standpoint of mono-materialization and cost, there are cases where it is desired to make the gas barrier resin layer thinner. When the gas barrier resin layer is thin, the above-mentioned aggregates tend to be easily formed due to heat, but the above-mentioned means tend to suppress the formation of aggregates. This is presumably because the reaction between EVOH and acid-modified polyolefin can be prevented from proceeding too quickly.

In one embodiment, the thickness of the gas barrier resin layer is preferably smaller than the thickness of the polyolefin resin layer. Such a laminate film has, for example, excellent recyclability. The thickness of the gas barrier resin layer is preferably smaller than the thickness of the polyolefin resin layer by 5 μm or more, and more preferably by 10 μm or more.

<Adhesive Resin Layer>
The laminate film of the present disclosure includes an adhesive resin layer between a polyolefin resin layer and a gas barrier resin layer, and such a laminate film has, for example, excellent interlayer adhesion between the polyolefin resin layer and the gas barrier resin layer.

The adhesive resin layer contains an acid-modified resin. Examples of acid-modified resins include acid-modified polyolefins and acid-modified vinyl resins. Among these, from the viewpoints of recyclability and adhesion, acid-modified polyolefins are preferred, and acid-modified polyethylene and acid-modified polypropylene are more preferred. When the polyolefin resin layer is a polyethylene resin layer, acid-modified polyethylene is preferred, and when the polyolefin resin layer is a polypropylene resin layer, acid-modified polypropylene is preferred.

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

The melt flow rate (MFR) of the acid-modified polyolefin is preferably 1 g/10 min or more, more preferably 3 g/10 min or more, even more preferably 5 g/10 min or more, still more preferably 7 g/10 min or more, and particularly preferably 9 g/10 min or more. An acid-modified polyolefin having an MFR equal to or higher than the lower limit has a high flow rate during, for example, coextrusion cast film formation, and therefore can suppress retention in a die, and tends to suppress the above-mentioned reaction with EVOH from proceeding too far even if the die temperature or resin temperature during cast film formation is increased.
From the viewpoint of film-forming properties, the MFR of the acid-modified polyolefin is preferably 50 g/10 min or less, more preferably 40 g/10 min or less, even more preferably 30 g/10 min or less, still more preferably 20 g/10 min or less, and particularly preferably 15 g/10 min or less.
The MFR of the acid-modified polyolefin is measured by Method A under a load of 2.16 kg in accordance with JIS K7210-1: 2014. The measurement temperature for the MFR is set according to the melting point of the acid-modified polyolefin, and is, for example, 190°C for acid-modified polyethylene and 230°C for acid-modified polypropylene.

The content ratio of the structural unit derived from the acid-modified component in the acid-modified polyolefin is preferably 3% by mass or less. The acid-modified polyolefin having the above content ratio of the upper limit or less has a small number of groups that can react with EVOH, for example, and therefore tends to be able to suppress the above-mentioned reaction from proceeding too far. The lower limit of the content ratio of the structural unit derived from the acid-modified component in the acid-modified polyolefin is not particularly limited, and may be, for example, 0.001% by mass, 0.005% by mass, or 0.01% by mass.
The content of the structural units derived from the acid-modified component is measured by infrared spectroscopy.

For a sample taken from the adhesive resin layer, an infrared absorption spectrum (IR spectrum) is obtained by total reflection (ATR) measurement using an infrared spectrophotometer, with the horizontal axis representing wave number (cm ^-1 ) and the vertical axis representing absorption intensity, and the intensity of each peak is calculated. Specifically, in the IR spectrum, the intensity 1 of the peak assigned to C=O stretching vibration in the 1700-1800 cm ^-1 region (preferably the 1710-1745 cm ^-1 region) and the intensity 2 of the peak assigned to C-H deformation vibration in the 1400-1500 cm ^-1 region (preferably the 1450-1470 cm ^-1 region) are calculated.

The IR intensity ratio (intensity 1/intensity 2) is preferably less than 0.4, more preferably 0.35 or less, even more preferably 0.3 or less, even more preferably 0.25 or less, and particularly preferably 0.2 or less, 0.15 or less, or 0.1 or less. Such an adhesive resin layer tends to be able to suppress the formation of the above-mentioned aggregates. This is presumably because the degree of acid modification in the acid-modified polypropylene is appropriately low, and the above-mentioned reaction can be appropriately suppressed. The IR intensity ratio (intensity 1/intensity 2) is preferably 0.01 or more, more preferably 0.02 or more, and even more preferably 0.03 or more. Such an adhesive resin layer also tends to have excellent adhesion to the gas barrier resin layer.

The infrared absorption spectrum using an infrared spectrophotometer is measured under the following measurement conditions.
(Measurement conditions)
Measurement equipment: Fourier transform infrared spectrophotometer Nicolet 6700
(Thermo Scientific)
Measurement method: Macro ATR (prism used: germanium (Ge))
Measurement environment: temperature 25℃
Resolution: 4 ^cm
Accumulation number: 32 times Incident angle: 45°

The adhesive resin layer may contain the above additives.

The thickness of the adhesive resin layer is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 10 μm or less, more preferably 7 μm or less. A laminate film having an adhesive resin layer whose thickness is equal to or greater than the lower limit has, for example, excellent adhesion. A laminate film having an adhesive resin layer whose thickness is equal to or less than the upper limit has, for example, excellent recyclability.

<Vapor-deposited film>
The laminated film of the present disclosure may further include a vapor deposition film on the gas barrier resin layer. In one embodiment, the laminated film of the present disclosure includes a vapor deposition film on the surface of the gas barrier resin layer. The gas barrier resin layer and the vapor deposition film are preferably in contact with each other. A laminated film including a vapor deposition film on a gas barrier resin layer is excellent in, for example, gas barrier properties, specifically, oxygen barrier properties and water vapor barrier properties. In addition, a laminated film including a vapor deposition film that is a metal vapor deposition film is excellent in, for example, brightness. A packaging container including such a laminated film as a substrate or sealant film can suppress the mass loss of the contents filled in the packaging container.

Examples of the vapor deposition film include a vapor deposition film containing one or more metals, a vapor deposition film containing one or more inorganic oxides, and a vapor deposition film containing one or more metals and one or more inorganic oxides. 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 these, aluminum vapor deposition film, aluminum oxide (alumina) vapor deposition film, silicon oxide (silica) vapor deposition film, and silicon carbide oxide vapor deposition film are preferred.

The thickness of the vapor-deposited film is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more, and is preferably 150 nm or less, more preferably 100 nm or less, and even more preferably 80 nm or less. A laminated film having a vapor-deposited film with a thickness equal to or greater than the lower limit has, for example, excellent gas barrier properties. A laminated film having a vapor-deposited film with a thickness equal to or less than the upper limit can, for example, suppress the occurrence of cracks in the vapor-deposited film and has excellent recyclability.

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. A laminate film having such a vapor-deposited film has, for example, excellent gas barrier properties while maintaining productivity. The OD value is measured in accordance with JIS K7361-1:1997.

It is preferable that the surface of the deposited film is subjected to the above-mentioned surface treatment. This can improve the adhesion between the deposited film and adjacent layers, for example.

Methods for forming the vapor deposition film include, for example, physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. The vapor deposition film may be a composite film containing two or more layers of different types of vapor deposition films, formed by using both physical vapor deposition and chemical vapor deposition.

The vapor-deposited film may be a single layer formed by a single vapor deposition process, or may be a multilayer formed by multiple vapor deposition processes. When the vapor-deposited film is a multilayer film, each layer may be composed of the same components or different components. Each layer may be formed by the same method or different methods.

<Barrier Coat Layer>
The laminate film of the present disclosure may further include a barrier coat layer on the vapor-deposited film. That is, the laminate film may further include a barrier coat layer on the surface of the vapor-deposited film opposite to the surface facing the gas barrier resin layer. Such a laminate film has, for example, excellent gas barrier properties, and can effectively suppress the occurrence of cracks in the vapor-deposited film, for example, when the vapor-deposited film contains inorganic oxides such as aluminum oxide and silicon oxide.

In one embodiment, the barrier coat layer contains a gas barrier resin. Examples of gas barrier resins include ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyacrylonitrile, polyester, polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide, polyurethanes, and (meth)acrylic resins.

The content of the gas barrier resin in the barrier coat layer is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. A laminate film having such a barrier coat layer has, for example, excellent gas barrier properties.
The barrier coat layer may contain the above-mentioned additives.

The thickness of the barrier coat layer containing the gas barrier resin is preferably 0.01 μm or more, more preferably 0.1 μm or more, and preferably 10 μm or less, more preferably 5 μm or less. A laminate film having a barrier coat layer whose thickness is equal to or greater than the lower limit has, for example, excellent gas barrier properties. A laminate film having a barrier coat layer whose thickness is equal to or less than the upper limit has, for example, excellent processability and recyclability.

The barrier coat layer can be formed, for example, by applying a coating liquid obtained by dissolving or dispersing a material such as a gas barrier resin in water or a suitable organic solvent to the surface of the vapor-deposited film and drying it.

In another embodiment, the barrier coat layer is a gas barrier coating film formed by mixing a metal alkoxide, a water-soluble polymer, and optionally a silane coupling agent, and adding water, an organic solvent, and a sol-gel catalyst as necessary to obtain a gas barrier composition, which is then applied to the surface of the deposition film and dried. The gas barrier coating film contains a hydrolysis polycondensate obtained by hydrolyzing and polycondensing the above-mentioned metal alkoxide, etc., by the sol-gel method. A laminate film having such a barrier coat layer on a deposition film can effectively suppress the occurrence of cracks in the deposition film, for example, when the deposition film contains an inorganic oxide.

Examples of metal alkoxides include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Examples of water-soluble polymers include hydroxyl-containing polymers such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers. Examples of organic solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol. Examples of sol-gel process catalysts are acids or amine-based compounds.

The thickness of the gas barrier coating film is preferably 0.01 μm or more, more preferably 0.1 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 5 μm or less. A laminate film having such a gas barrier coating film has, for example, excellent gas barrier properties, can suppress the occurrence of cracks in a vapor deposition film containing an inorganic oxide, and has excellent recyclability and processability.

[Laminate]
The laminate of the present disclosure comprises:
A substrate;
A sealant layer;
are provided in this order in the thickness direction.
The laminate of the present disclosure, in one embodiment, is a packaging material.

In one embodiment, the sealant layer is the laminated film of the present disclosure, in which the laminated film is disposed so that the gas barrier resin layer faces the substrate.
In one embodiment, the substrate is a polyolefin resin substrate.
For example, the polyolefin resin substrate is a polyethylene resin substrate containing polyethylene as a main component, and the polyolefin resin layer in the laminated film is a polyethylene resin layer containing polyethylene as a main component,
The polyolefin resin substrate is a polypropylene resin substrate containing polypropylene as a main component, and the polyolefin resin layer in the laminated film is a polypropylene resin layer containing polypropylene as a main component, or
The polyolefin resin substrate is a polypropylene resin substrate containing polypropylene as a main component, and the polyolefin resin layer in the laminated film is a polyethylene resin layer containing polyethylene as a main component.

In one embodiment, the substrate is a laminate film of the present disclosure.
The sealant layer in this case will be described later.

In one embodiment, the laminate of the present disclosure comprises:
A polyolefin resin substrate;
An intermediate substrate;
A sealant layer;
are provided in this order in the thickness direction.

The intermediate substrate is a laminate film of the present disclosure.
Such a laminate has, for example, excellent impact resistance.
For example, the polyolefin resin substrate is a polyethylene resin substrate containing polyethylene as a main component, the polyolefin resin layer in the intermediate substrate is a polyethylene resin layer containing polyethylene as a main component, and the sealant layer is a polyethylene resin layer containing polyethylene as a main component, or
The polyolefin resin substrate is a polypropylene resin substrate containing polypropylene as a main component, the polyolefin resin layer in the intermediate substrate is a polypropylene resin layer containing polypropylene as a main component, and the sealant layer is a polypropylene resin layer containing polypropylene as a main component.

The laminate 1 shown in FIG. 5 comprises, in this order, a polyolefin resin substrate 20, an adhesive layer 30, and a laminate film 10 as a sealant layer. The laminate film 10 comprises, in this order, a polyolefin resin layer 12, an adhesive resin layer 13, and a gas barrier resin layer 14, and optionally a vapor deposition film 15. The laminate 1 shown in FIG. 6 comprises, in this order, a polyolefin resin substrate 20, an adhesive layer 30, a polyolefin resin substrate 20, an adhesive layer 30, and a laminate film 10 as a sealant layer. In one embodiment, the laminate 1 further comprises a printed layer (not shown) on the polyolefin resin substrate 20. The printed layer is usually formed on the surface of the polyolefin resin substrate 20 facing the laminate film 10.

The laminate 1 shown in FIG. 7 comprises, in this order, a polyolefin resin substrate 20, an adhesive layer 30, a laminate film 10 as an intermediate substrate, the adhesive layer 30, and a sealant layer 40. The laminate film 10 comprises, in this order, a polyolefin resin layer 12, an adhesive resin layer 13, and a gas barrier resin layer 14, and optionally a vapor deposition film 15. In one embodiment, the laminate 1 further comprises a printed layer (not shown) on the polyolefin resin substrate 20. The printed layer is usually formed on the surface of the polyolefin resin substrate 20 facing the laminate film 10.

Specific examples of the layer structure of the laminate of the present disclosure are shown below.
(1) A laminate comprising, in this order, a polypropylene resin substrate, an optional printed layer, an adhesive layer, and a laminate film of the present disclosure as a sealant layer (optionally a vapor deposition film, a gas barrier resin layer, an acid-modified polypropylene resin layer, and a polypropylene resin layer). (2) A laminate comprising, in this order, a polyethylene resin substrate, an optional printed layer, an adhesive layer, and a laminate film of the present disclosure as a sealant layer (optionally a vapor deposition film, a gas barrier resin layer, an acid-modified polyethylene resin layer, and a polyethylene resin layer). (3) A laminate comprising, in this order, a polypropylene resin substrate, an optional printed layer, an adhesive layer, and a laminate film of the present disclosure as a sealant layer (optionally a vapor deposition film, a gas barrier resin layer, an acid-modified polyethylene resin layer, and a polyethylene resin layer). (4) A laminate comprising, in this order, a polypropylene resin substrate, an optional printed layer, and an adhesive layer. a laminate comprising, in this order, a polypropylene resin substrate, a laminate film of the present disclosure (optionally a vapor deposition film, a gas barrier resin layer, an acid-modified polypropylene resin layer, and a polypropylene resin layer) as an intermediate substrate, an adhesive layer, and a polypropylene-based sealant layer; (5) a laminate comprising, in this order, a polypropylene resin substrate, a printed layer, an adhesive layer, a laminate film of the present disclosure (optionally a vapor deposition film, a gas barrier resin layer, an acid-modified polypropylene resin layer, and a polypropylene resin layer) as an intermediate substrate, an adhesive layer, and a polyethylene-based sealant layer; (6) a laminate comprising, in this order, a polyethylene resin substrate, a printed layer, an adhesive layer, a laminate film of the present disclosure (optionally a vapor deposition film, a gas barrier resin layer, an acid-modified polyethylene resin layer, and a polyethylene resin layer) as an intermediate substrate, an adhesive layer, and a polyethylene-based sealant layer;

In one embodiment, the resin constituting the polyolefin resin substrate and the resin constituting the polyolefin resin layer of the laminated film are both primarily made of polyolefin, which can improve the recyclability of the laminate, for example.

The content of polyolefin (specifically, polypropylene or polyethylene) in the entire laminate of the present disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 88% by mass or more, and particularly preferably 90% by mass or more. Such a laminate can be used to produce, for example, a mono-material packaging container, and can improve the recyclability of the packaging container. The upper limit of the polyolefin content is not particularly limited, but may be, for example, 99% by mass or 95% by mass. The polyolefin content in the laminate means the ratio of the polyolefin content to the sum of the contents of the resin materials in each layer constituting the laminate.

<Polyolefin resin substrate>
In one embodiment, the polyolefin resin substrate contains polyolefin as a main component, i.e., in the range of more than 50 mass%. Examples of polyolefin include polypropylene, polyethylene, and polymethylpentene. As the polyolefin resin substrate, a polyethylene resin substrate and a polypropylene resin substrate are preferred.

From the viewpoint of film-forming property and processability, the MFR of the polyolefin 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, and is preferably 50 g/10 min or less, more preferably 30 g/10 min or less, even more preferably 10 g/10 min or less.

The polyolefin content in the polyolefin resin 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.

The polyolefin resin substrate may contain a resin material other than polyolefin, such as (meth)acrylic resin, vinyl resin, cellulose resin, polyamide, polyester, and ionomer resin.
The polyolefin resin substrate may contain the above-mentioned additives.

In one embodiment, the polyolefin resin substrate is a substrate that has been subjected to a stretching process, i.e., a stretched substrate. Such a substrate is, for example, excellent in strength, heat resistance, and transparency. The stretching process may be uniaxial stretching or biaxial stretching. The stretching ratio when stretching in the machine direction (flow direction of the substrate, MD direction) is preferably 2 times or more, more preferably 3 times or more, and preferably 10 times or less, more preferably 7 times or less. 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, and preferably 10 times or less, more preferably 7 times or less. By setting the stretching ratio to 2 times or more, for example, the strength, heat resistance, and transparency of the substrate can be improved, and the printability of the substrate can be improved. From the viewpoint of the breaking limit of the substrate, the stretching ratio is preferably 10 times or less.

The polyolefin resin substrate can be produced, for example, by forming a film from polyolefin or its resin composition using a T-die method, inflation method, or the like, and then stretching the film. With the inflation method, film formation and stretching can be carried out simultaneously.

In one embodiment, the polyolefin resin substrate may be subjected to the above-mentioned surface treatment, which can improve the adhesion between the polyolefin resin substrate and other layers, for example.
An easy-adhesion layer may be provided on the surface of the polyolefin resin substrate.

The haze value of the polyolefin resin substrate is preferably 25% or less, more preferably 15% or less, and even more preferably 10% or less. The smaller the haze value, the better, but the lower limit may be, for example, 0.1% or 1%. The haze value of the substrate is measured in accordance with JIS K7136:2000.

The polyolefin resin substrate may have a single-layer structure or a multi-layer structure.
The thickness of the polyolefin resin substrate is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 10 μm or more, and is preferably 300 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. A laminate having a polyolefin resin substrate with a thickness equal to or greater than the lower limit has, for example, excellent strength and heat resistance. A laminate having a polyolefin resin substrate with a thickness equal to or less than the upper limit has, for example, excellent processability.

(Polyethylene resin substrate)
In one embodiment, the polyethylene resin substrate contains polyethylene as a main component, i.e., in a range of more than 50% by mass.
The details of the polyethylene are as described above.
Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene. From the viewpoint of strength and heat resistance of the polyethylene resin substrate, high-density polyethylene and medium-density polyethylene are preferred. From the viewpoint of reducing the environmental load, polyethylene derived from biomass or polyethylene that has been mechanically recycled or chemically recycled may be used.

The polyethylene content in the polyethylene resin 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. A laminate having such a polyethylene resin substrate has, for example, excellent recyclability.

In one embodiment, the polyethylene resin substrate is a uniaxially stretched film or a biaxially stretched film, for example a uniaxially stretched film, more specifically a uniaxially stretched film that has been stretched in the machine direction (MD).

The polyethylene resin substrate may have a single layer structure or a multilayer structure. Hereinafter, a polyethylene resin substrate having a multilayer structure and having been stretched is also referred to as a "stretched multilayer PE substrate." A stretched multilayer PE substrate is preferable from the viewpoints of strength, heat resistance, and suitability for stretching.

In a stretched multi-layer PE substrate, the density of the polyethylene constituting each layer may be the same or different. For example, the stretched multi-layer PE substrate may have a gradient in density (density gradient) for each layer. By providing a density gradient in the stretched multi-layer PE substrate, for example, its strength, heat resistance, and stretchability can be improved.

The stretched multi-layer PE substrate has a multi-layer structure of two or more layers. In one embodiment, the number of layers of the stretched multi-layer PE substrate is two or more and seven or less, for example, three or more and seven or less, or three or more and five or less. The number of layers of the stretched multi-layer PE substrate is preferably an odd number, for example, three, five or seven layers. The multi-layer structure of the stretched multi-layer PE substrate can improve the balance of the rigidity, strength, heat resistance, printability and stretchability of the substrate. Each layer of the stretched multi-layer PE substrate is preferably composed of polyethylene.

The stretched multilayer PE substrate can be produced, for example, by forming a laminate from a plurality of resin materials or resin compositions by the inflation method or the T-die method, and stretching the resulting laminate. The stretching process can improve the transparency, rigidity, strength, and heat resistance of the substrate, and the substrate can be suitably used, for example, as a substrate for packaging materials. In one embodiment, the stretched multilayer PE substrate is obtained by stretching a laminate (precursor) having a multilayer structure. Specifically, the resin materials constituting each layer are co-extruded into a tube shape to form a film, and the laminate can be produced. Alternatively, the resin materials constituting each layer are co-extruded into a tube shape, and then the opposing layers are pressed together by a rubber roll or the like to produce a laminate. By producing a laminate by such a method, the number of defective products can be significantly reduced and production efficiency can be improved.

Below, several examples of embodiments of the stretched multilayer PE substrate are described. Hereinafter, a layer with a polyethylene content of 80% by mass or more is referred to as a "polyethylene layer." For example, a layer with a high-density polyethylene content of 80% by mass or more is referred to as a "high-density polyethylene layer."

Examples of stretched multilayer PE substrates include:
A substrate comprising, in this order, a medium density polyethylene layer, a high density polyethylene layer, a blend layer of medium density polyethylene and high density polyethylene, a high density polyethylene layer, and a medium density polyethylene layer;
A substrate comprising, in this order, a medium density polyethylene layer, a medium density polyethylene layer, a blend layer of medium density polyethylene and linear low density polyethylene, a medium density polyethylene layer, and a medium density polyethylene layer;
A substrate comprising, in this order, a blend layer of medium density polyethylene and high density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, a linear low density polyethylene layer, a blend layer of medium density polyethylene and linear low density polyethylene, and a blend layer of medium density polyethylene and high density polyethylene;
a substrate comprising, in this order, a blend layer of medium density polyethylene and high density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, a blend layer of medium density polyethylene and linear low density polyethylene, and a blend layer of medium density polyethylene and high density polyethylene; a substrate comprising, in this order, a blend layer of high density polyethylene and medium density polyethylene, a medium density polyethylene layer, a blend layer of linear low density polyethylene and medium density polyethylene, a medium density polyethylene layer, and a blend layer of high density polyethylene and medium density polyethylene;
A substrate comprising, in this order, a layer containing medium density polyethylene and high density polyethylene, a layer containing high density polyethylene, a layer containing linear low density polyethylene, a layer containing high density polyethylene, and a layer containing medium density polyethylene and high density polyethylene;
A substrate comprising, in this order, a layer containing medium density polyethylene and high density polyethylene, a layer containing medium density polyethylene and linear low density polyethylene, a layer containing linear low density polyethylene, a layer containing high density polyethylene, and a layer containing medium density polyethylene and high density polyethylene;
Examples include:

(Polypropylene resin base material)
In one embodiment, the polypropylene resin substrate contains polypropylene as a main component, i.e., in a range of more than 50 mass %. A laminate including the polypropylene resin substrate has, for example, excellent oil resistance.

The polypropylene may be any of a propylene homopolymer, a propylene random copolymer, and a propylene block copolymer, or may be a mixture of two or more selected from these. From the viewpoint of reducing the environmental load, the polypropylene may be biomass-derived polypropylene or mechanically recycled or chemically recycled polypropylene. Details of these are as described above.

Among polypropylenes, it is preferable to use propylene homopolymer or propylene random copolymer from the viewpoint of transparency. When emphasis is placed on the rigidity and heat resistance of the packaging container, it is preferable to use propylene homopolymer. When emphasis is placed on the impact resistance of the packaging container, it is preferable to use propylene random copolymer.

The polypropylene content in the polypropylene resin substrate is preferably more than 50% by mass, more preferably 80% by mass or more, even more preferably 85% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. A laminate including such a polypropylene resin substrate has, for example, excellent recyclability.
The polypropylene resin substrate may have a single-layer structure or a multi-layer structure.

<Printed layer>
The laminate of the present disclosure may include a printed layer on the surface of a substrate such as a polyolefin resin substrate and an intermediate substrate. Examples of images formed on the printed layer include characters, patterns, symbols, and combinations thereof. The printed layer may be formed using, for example, an ink derived from biomass. This can, for example, further reduce the environmental load.

Methods for forming the printing layer include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing. Among these, flexographic printing is preferred from the viewpoint of reducing the environmental impact.

The printed layer may be formed on either side of the polyolefin resin substrate. It is preferable that the printed layer is formed on the surface of the polyolefin resin substrate facing the sealant layer, since this can prevent the printed layer from coming into contact with the outside air and prevent deterioration of the printed layer over time. The printed layer may be formed on either side of the intermediate substrate.

<Sealant Layer>
In one embodiment, the sealant layer is the laminate film of the present disclosure described above. In this case, the laminate film is arranged so that the gas barrier resin layer faces the substrate. Since the details of the laminate film are as described above, the description will be omitted in this section. In one embodiment, the polyolefin resin layer in the laminate film is made of the same type of resin material as the polyolefin resin substrate, such as a polyethylene resin layer in the case of a polyethylene resin substrate, and a polypropylene resin layer in the case of a polypropylene resin substrate. This allows the packaging container to be made mono-material. After collecting the used packaging container, there is no need to separate the substrate and the sealant layer, and the recycling suitability of the packaging container can be improved.

In one embodiment, the sealant layer is a resin layer containing polyolefin as the main component, i.e., in a range of more than 50% by mass. In one embodiment, the sealant layer is composed of the same type of resin material as the polyolefin resin substrate and/or the same type of resin material as the polyolefin resin layer of the laminated film. This allows the packaging container to be made mono-material. After collecting used packaging containers, there is no need to separate the substrate and the sealant layer, and the recycling suitability of the packaging container can be improved.

Among the polyolefins, polyethylene and polypropylene are preferred.
Examples of polyethylene include high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, and very low density polyethylene, and from the viewpoint of heat sealability, low density polyethylene, linear low density polyethylene, and very low density polyethylene are preferred. From the viewpoint of reducing the environmental load, biomass-derived polyethylene and/or recycled polyethylene may be used.
Examples of polypropylene include propylene homopolymers, propylene random copolymers such as propylene-α-olefin random copolymers, and propylene block copolymers such as propylene-α-olefin block copolymers. Details of the α-olefins are as described above. From the viewpoint of reducing the environmental load, biomass-derived polypropylene and/or recycled polypropylene may be used.

The polyolefin content in the sealant layer is preferably more than 50% by mass, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more. A laminate having such a sealant layer has, for example, excellent recyclability.

The sealant layer may contain the above additives.

The thickness of the sealant layer is preferably 5 μm or more, more preferably 10 μm or more, and is preferably 100 μm or less, more preferably 80 μm or less. When the sealant layer has a multi-layer structure, it is preferable that the total thickness is within the above range.

From the viewpoint of heat sealability, the sealant layer is preferably an unstretched resin film, more preferably an unstretched coextruded resin film, and each layer constituting the sealant layer is a coextruded resin layer. The above resin film can be produced, for example, by using the T-die method or the inflation method.

The sealant layer may contain a heat seal modifier from the viewpoint of improving low-temperature heat sealability. The heat seal modifier is not particularly limited as long as it is a component that has excellent compatibility with the polyolefin that constitutes the sealant layer, but examples of the heat seal modifier include olefin-based polymers with low melting points, specifically olefin-based copolymers. Ultra-low density polyethylene may also be used. Details of the heat seal modifier are as described above.

The content of the heat seal modifier in the entire sealant layer is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less. Such a sealant layer has, for example, excellent heat sealability.

The sealant layer may have a single-layer structure or a multi-layer structure.
In one embodiment, the surface layer of the sealant layer having a multi-layer structure on the side opposite to the substrate contains polyolefin and a heat seal modifier. The content of the heat seal modifier in the surface layer is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 55% by mass or less, more preferably less than 50% by mass. The content of the polyolefin in the surface layer is preferably 45% by mass or more, more preferably more than 50% by mass, and preferably 90% by mass or less, more preferably 80% by mass or less. The sealant layer having such a surface layer has, for example, excellent heat sealability and recyclability.

The thickness of the surface layer is preferably 1 μm or more, more preferably 2 μm or more, and is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. A sealant layer having such a surface layer has, for example, excellent heat sealability and recyclability.

<Adhesive Layer>
The laminate of the present disclosure may include an adhesive layer between any layers, such as between the substrate and the sealant layer, between the polyolefin resin substrate and the intermediate substrate, between the intermediate substrate and the sealant layer, etc. Such a laminate has, for example, excellent adhesion between layers.

The adhesive layer is, for example, composed of an adhesive, and the adhesive may be any of a one-component curing adhesive, a two-component curing adhesive, and a non-curing adhesive. The adhesive may be a solventless adhesive or a solvent-based adhesive. Examples of adhesives include polyether-based adhesives, polyester-based adhesives, polyurethane-based adhesives, silicone-based adhesives, epoxy-based adhesives, rubber-based adhesives, vinyl-based adhesives, olefin-based adhesives, and phenol-based adhesives. Among these, polyurethane-based adhesives are preferred, and two-component curing polyurethane-based adhesives are more preferred.

The thickness of the adhesive layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.5 μm or more, particularly preferably 0.8 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6 μm or less, particularly preferably 5 μm or less.

The adhesive layer can be formed by applying an adhesive to an object by a conventional method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine, or transfer roll coating, and drying as desired. The laminate of the present disclosure may be manufactured, for example, by laminating a substrate and a sealant film, or a polyolefin resin substrate, an intermediate substrate, and a sealant film, by a non-solvent lamination method using a solvent-free adhesive, or by a dry lamination method using a solvent-based adhesive.

[Packaging container]
The laminate of the present disclosure can be suitably used as a packaging material. The packaging material is used to produce a packaging container. The packaging material comprises the laminate of the present disclosure. The packaging container can be produced by using at least the packaging material comprising the laminate of the present disclosure.

The packaging container of the present disclosure comprises the laminate of the present disclosure. Examples of packaging containers include packaging bags, tube containers, and containers with lids. The containers with lids comprise a container body having a storage section, and a lid material joined (heat sealed) to the container body so as to seal the storage section.

The packaging container has a heat-sealed portion. Examples of heat-sealing methods include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high-frequency sealing, and ultrasonic sealing.

Examples of packaging bags include various types of packaging bags such as standing pouch type, side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, hem seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type. Specific examples of packaging bags include small bags and standing pouches. The packaging container may have an easy-to-open part. Examples of easy-to-open parts include a notch part that serves as the starting point for tearing the packaging container, and a half-cut line formed by laser processing or a cutter as a path for tearing the packaging container.

The contents contained in the packaging container include, for example, liquids, solids, powders, and gels. The contents may be food or beverages, or non-food or beverages such as chemicals, cosmetics, medicines, metal parts, and electronic parts. Specific examples of the contents include sauces, soy sauce, dressings, ketchup, syrups, cooking alcohol, edible oils, mayonnaise, and other liquid or viscous seasonings; liquid soups, powdered soups, fruit juices; spices; liquid beverages, jelly-like beverages, instant foods, and other food and beverages; shampoos, rinses, conditioners, hand soaps, body soaps, air fresheners, deodorants, insect repellents, detergents; creams; and metal parts and electronic parts. After the contents are contained in the packaging container, the packaging container can be sealed by heat-sealing the opening of the packaging container.

In one embodiment, a packaging bag can be produced by folding the laminate of the present disclosure in half and stacking it so that the base material is on the outside and the sealant layer is on the inside, and then heat-sealing the ends, etc. In another embodiment, a packaging bag can be produced by stacking multiple laminates of the present disclosure so that the sealant layers face each other, and then heat-sealing the ends, etc. The entire packaging bag may be composed of the above-mentioned laminate, or only a part of the packaging bag may be composed of the above-mentioned laminate. Figure 8 shows an example of a packaging bag. In the figure, the shaded areas represent the heat-sealed parts.

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

In one embodiment, the standing pouch comprises a body portion (side sheet) and a bottom portion (bottom sheet). The side sheet and the bottom sheet may be made of the same material or different materials. The bottom sheet retains the shape of the side sheet, which gives the pouch self-supporting properties and allows it to be a standing pouch. A storage space for storing contents is formed within the area surrounded by the side sheet and the bottom sheet. In the standing pouch, only the body portion may be made of the laminate of the present disclosure, only the bottom portion may be made of the laminate of the present disclosure, or both the body portion and the bottom portion may be made of the laminate of the present disclosure.

In one embodiment, the side sheet can be formed by making a bag so that the sealant 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, stacking them so that the sealant layers face each other, and heat-sealing the side edges on both sides to make a bag.

In another embodiment, the side sheet can be formed by preparing two laminates of the present disclosure, stacking them with the sealant layers facing each other, inserting two laminates folded in a V-shape with the sealant layers facing outward between the laminates at the side edges on both sides of the stacked laminates, and heat sealing them. This manufacturing method produces a standing pouch having a body with side gussets. Figure 9 shows an example of a standing pouch. The shaded areas in the figure represent the heat-sealed areas.

In one embodiment, the bottom sheet can be formed by inserting the laminate of the present disclosure between the lower parts of the side sheets that have been made into a bag and heat sealing it. More specifically, the bottom sheet can be formed by inserting a laminate folded into a V shape with the sealant layer on the outside between the lower parts of the side sheets that have been made into a bag and heat sealing it.

In one embodiment, two sheets of the above laminate are prepared and stacked together with the sealant layers facing each other. Next, another sheet of the above laminate is folded in a V shape with the sealant layer facing outward, and this is sandwiched between the lower part of the stacked sheets that are now facing each other and heat sealed to form the bottom. Next, the two sides adjacent to the bottom are heat sealed to form the body. In this manner, the standing pouch of one embodiment can be formed.

The present disclosure relates to, for example, the following [1] to [14].
[1] A laminated film comprising, in this order, a polyolefin resin layer, an adhesive resin layer, and a gas barrier resin layer, the adhesive resin layer containing an acid-modified resin as a main component, and the gas barrier resin layer containing at least one resin selected from an ethylene-vinyl alcohol copolymer and a polyamide.
[2] The laminate film according to [1] above, which is an unstretched cast film.
[3] The laminate film according to [1] or [2], wherein the gas barrier resin layer is a layer containing an ethylene-vinyl alcohol copolymer as a main component, a layer containing a polyamide as a main component, or a layer containing a mixed resin of an ethylene-vinyl alcohol copolymer and a polyamide as a main component.
[4] The ethylene-vinyl alcohol copolymer has an ethylene-derived structural unit content of 30 mol% or more and 60 mol% or less, and a melt flow rate (MFR) of 0.1 g/10 min or more and 5 g/10 min or less. The laminate film according to any one of the above [1] to [3].
[5] The laminate film according to any one of [1] to [4], wherein the acid-modified resin is an acid-modified polyolefin.
[6] The laminate film according to [5], wherein the acid-modified polyolefin is at least one selected from acid-modified polyethylene and acid-modified polypropylene.
[7] The laminate film according to any one of [1] to [6], wherein the polyolefin resin layer is a polypropylene resin layer containing polypropylene as a main component, the adhesive resin layer is a layer containing an acid-modified polypropylene as a main component, and the gas barrier resin layer is a layer containing an ethylene-vinyl alcohol copolymer as a main component, and the adhesive resin layer has a ratio (intensity 1/intensity 2) of the intensity 1 of the peak attributable to C=O stretching vibration in the 1700 to 1800 cm- ¹ region and the intensity 2 of the peak attributable to C-H bending vibration in the 1400 to 1500 cm ^-1 region, as measured by an attenuated total reflection (ATR) measurement method using an infrared spectrophotometer, of less than 0.4.
[8] The laminate film according to [7], wherein the ethylene-vinyl alcohol copolymer has a content of ethylene-derived structural units of 30 mol% or more and 60 mol% or less, a melt flow rate (MFR) of 0.1 g/10 min or more and 5 g/10 min or less, and the acid-modified polypropylene has an MFR of 1 g/10 min or more and 15 g/10 min or less.
[9] The laminate film according to any one of [1] to [8], wherein the polyolefin resin layer is a polyethylene resin layer containing polyethylene as a main component, or a polypropylene resin layer containing polypropylene as a main component.
[10] The polyolefin resin layer comprises a first resin layer containing a polyolefin and a second resin layer containing a polyolefin and a heat seal modifier, and the second resin layer constitutes one of the surface layers of the laminate film. The laminate film according to any one of [1] to [9].
[11] The laminate film according to any one of [1] to [10], further comprising a vapor-deposited film provided on the gas barrier resin layer.
[12] The laminate film according to any one of [1] to [11] above, which is used as the sealant layer constituting a packaging material having a substrate and a sealant layer.
[13] The laminate film according to any one of [1] to [9] and [11], which is used as the substrate constituting a packaging material having a substrate and a sealant layer.
[14] The laminate film according to any one of [1] to [9] and [11], which is used as the intermediate substrate constituting a packaging material having a polyolefin resin substrate, an intermediate substrate, and a sealant layer in this order.

The laminate film and laminate of the present disclosure will be specifically described below based on examples, but the laminate film and laminate of the present disclosure are not limited to the examples. Hereinafter, "parts by mass" will also be simply referred to as "parts".

[Resin material 1]
The resin materials used in the production of polyethylene-based laminated films are described below.
・Gas barrier resin: Ethylene-vinyl alcohol copolymer (EVOH)
Product name: EVAL E171B, manufactured by Kuraray Co., Ltd. Density: 1.140 g/cm ³ , Melting point: 165° C., MFR: 1.7 g/10 min Ethylene content: 44 mol %
・Gas barrier resin 6-66 copolymer nylon resin (Ny)
Product name: Ultramid C33LN, manufactured by BASF Corporation Density: 1.12 g/cm ³ , Melting point: 196° C., Relative viscosity: 3.3
Acid-modified resin: Maleic acid-modified polyethylene, product name: Admer NE827T, manufactured by Mitsui Chemicals, Inc., density: 0.910 g/cm ³ , melting point: 120° C., MFR: 5 g/10 min. High-density polyethylene 1 (hereinafter referred to as “HDPE (1)”)
Product name: XUS81841.27, manufactured by The Dow Chemical Company, density: 0.947 g/cm ³ , melting point: 128° C., MFR: 6.0 g/10 min. Linear low-density polyethylene 1 (hereinafter referred to as “LLDPE (1)”)
Product name: Exceed 3527PA, manufactured by ExxonMobil Corporation, density: 0.927 g/cm ³ , melting point: 121° C., MFR: 3.5 g/10 min. Linear low-density polyethylene 2 (hereinafter referred to as “LLDPE (2)”)
Product name: Elite 5220G, manufactured by The Dow Chemical Company, density: 0.915 g/cm ³ , melting point: 123° C., MFR: 3.5 g/10 min. Low-density polyethylene 1 (hereinafter referred to as “LDPE (1)”)
Product name: LD2420H, manufactured by PTT Corporation Density: 0.924 g/cm ³ , melting point: 111° C., MFR: 1.9 g/10 min. Polyolefin plastomer Product name: COHERE8102L, manufactured by SABIC Corporation Density: 0.902 g/cm ³ , melting point: 98° C., MFR: 1.0 g/10 min.

Blended polyethylene A
70 parts of LLDPE (1) and 30 parts of LDPE (1) were mixed to obtain a blended polyethylene A having an average density of 0.926 g/cm ³ .
・Blended polyethylene B
70 parts of HDPE (1) and 30 parts of LDPE (1) were mixed to obtain a blended polyethylene B having an average density of 0.940 g/cm ³ .
・Blended polyethylene C
90 parts of LLDPE (2) and 10 parts of LDPE (1) were mixed to obtain a blended polyethylene C having an average density of 0.916 g/cm ³ .
・Blended polyethylene D
60 parts of LLDPE (2) and 40 parts of polyolefin plastomer were mixed to obtain a blended polyethylene D having an average density of 0.910 g/cm ³ .

[Resin material 2]
The resin materials used in the production of polypropylene-based laminated films are described below.
・Gas barrier resin: Ethylene-vinyl alcohol copolymer (EVOH)
Product name: EVAL E171B, manufactured by Kuraray Co., Ltd. Density: 1.140 g/cm ³ , Melting point: 165° C., MFR: 1.7 g/10 min Ethylene content: 44 mol %
・Gas barrier resin 6-66 copolymer nylon resin (Ny)
Product name: Ultramid C33LN, manufactured by BASF Corporation Density: 1.12 g/cm ³ , Melting point: 196° C., Relative viscosity: 3.3
Acid-modified resin Maleic acid-modified polypropylene Product name: ADMER AT3351E, manufactured by Mitsui Chemicals, Inc. Density: 0.890 g/cm ³ , MFR: 11 g/10 min Content of structural units derived from maleic acid: 3 mass % or less IR intensity ratio (intensity 1/intensity 2) described above: 0.05
Acid-modified resin Maleic acid-modified polypropylene Product name: Admer QF551T, manufactured by Mitsui Chemicals, Inc. Density: 0.890 g/cm ³ , MFR: 5.7 g/10 min Content of structural units derived from maleic acid: 3 mass % or less IR intensity ratio (intensity 1/intensity 2) described above: 0.40
・Polypropylene 1 (hereinafter referred to as "PP1")
Propylene random copolymer: Product name: Cosmoplane FL7540, manufactured by TPC Corporation; Density: 0.900 g/cm ³ , Melting point: 138° C., MFR: 7 g/10 min. Polypropylene 2 (hereinafter referred to as “PP2”)
Propylene homopolymer: Product name: Cosmoplane FL7013, manufactured by TPC Corporation; Density: 0.900 g/cm ³ , Melting point: 165° C., MFR: 7 g/10 min. Polypropylene 3 (hereinafter referred to as “PP3”)
Propylene random copolymer: Trade name: Cosmoplane FL7642, manufactured by TPC Corporation; Density: 0.900 g/cm ³ , Melting point: 128° C., MFR: 7 g/10 min. Propylene-based elastomer: Trade name: Vistamaxx 3980FL, manufactured by ExxonMobil Corporation; Density: 0.879 g/cm ³ , Melting point: 128° C., MFR: 3.6 g/10 min.

Blended polypropylene A
60 parts of PP3 and 40 parts of a propylene-based elastomer were mixed to obtain a blended polypropylene A having an average density of 0.891 g/cm ³ .

[A1. Preparation of polyethylene sealant film]
[Example 1-1]
The EVOH, maleic acid modified polyethylene, blended polyethylene A, blended polyethylene B, blended polyethylene C and blended polyethylene D prepared above were extruded by a cast film forming method to produce a 6-layer film, comprising a gas barrier resin layer (3.2 μm)/adhesive resin layer (3.2 μm)/blend polyethylene A layer (3.2 μm)/blend polyethylene B layer (18.4 μm)/blend polyethylene C layer (8.8 μm)/blend polyethylene D layer (3.2 μm), and a total thickness of 40 μm of an unstretched polyethylene film was produced. The numbers in parentheses indicate the thickness of the layers.

A 60 nm thick aluminum vapor deposition film was formed on the gas barrier resin layer of the unstretched polyethylene film by PVD to obtain a polyethylene laminate film. The optical density (OD value) of the vapor deposition film was measured and found to be 3.0. This polyethylene laminate film was used as a sealant film.

[Example 1-2]
An unstretched polyethylene film and a polyethylene-based laminate film were produced in the same manner as in Example 1-1, except that the resin constituting the gas barrier resin layer was changed to the Ny prepared above.

[Comparative Example 1-1]
A 40 μm-thick unstretched polyethylene film consisting of an LLDPE (1) layer was produced by a cast film-forming method. A polyethylene-based film was produced in the same manner as in Example 1-1, except that this unstretched polyethylene film was used. An aluminum vapor deposition film was formed on the LLDPE (1) layer.

[Comparative Example 1-2]
An unstretched polyethylene film having a total thickness of 40 μm and including a LLDPE (1) layer (36 μm)/blend polyethylene D layer (4 μm) was produced by a cast film production method. The numbers in parentheses indicate the thickness of the layers. A polyethylene-based laminated film was produced in the same manner as in Example 1-1, except that this unstretched polyethylene film was used. An aluminum vapor deposition film was formed on the LLDPE (1) layer.

[A2. Preparation of stretched multilayer polyethylene substrate]
The resin materials used in the preparation of the multi-layer oriented polyethylene substrate are described below.
- High density polyethylene 2 (hereinafter referred to as "HDPE (2)")
Product name: Elite 5960G, manufactured by Dow Chemical, density: 0.960 g/cm ³ , melting point: 134° C., MFR: 0.8 g/10 min. High density polyethylene 3 (hereinafter referred to as “HDPE (3)”)
Product name: H619F, manufactured by SCG Corporation, density: 0.965 g/cm ³ , melting point: 135° C., MFR: 0.7 g/10 min. Medium density polyethylene 1 (hereinafter referred to as “MDPE (1)”)
Product name: Enable 4002MC, manufactured by ExxonMobil Corporation Density: 0.940 g/cm ³ , Melting point: 128° C., MFR: 0.25 g/10 min. Linear low-density polyethylene 3 (hereinafter referred to as “LLDPE (3)”)
Product name: Exceed XP8656ML, manufactured by ExxonMobil Corporation Density: 0.916 g/cm ³ , Melting point: 121° C., MFR: 0.5 g/10 min. MB containing slip agent
Product name: SLIP61 10061-K, manufactured by Ampacet Density: 0.910 g/cm ³ , MFR: 10 g/10 min Polyethylene base, containing 5% by mass of erucic acid amide slip agent

・Blended polyethylene A1
70 parts of MDPE (1) and 30 parts of HDPE (2) were mixed to obtain a blended polyethylene A1 having an average density of 0.948 g/cm ³ .
・Blended polyethylene B1
70 parts of MDPE (1) and 30 parts of LLDPE (3) were mixed to obtain a blended polyethylene B1 with an average density of 0.933 g/cm ³ .
・Blended polyethylene C1
98 parts of LLDPE (3) and 2 parts of MB containing slip agent were mixed to give a blended polyethylene C1 with an average density of 0.916 g/cm ³ .

The blended polyethylene A1, HDPE (3), blended polyethylene C1, and blended polyethylene B1 prepared above were extruded by inflation molding into a tubular film with a layer thickness ratio of blended polyethylene A1-1 layer (15 μm) / HDPE (3) layer (20 μm) / blended polyethylene C1 layer (55 μm) / blended polyethylene B1 layer (20 μm) / blended polyethylene A1-2 layer (15 μm). A polyethylene film with a total thickness of 125 μm was obtained, and the tubular film was folded at the nip to form two layers. The numbers in parentheses indicate the layer thickness. The polyethylene film prepared above was stretched in the machine direction (MD) at a stretch ratio of 5 times, and the blended polyethylene A1-2 layer was subjected to corona discharge treatment, and then the end was slit and divided into two to obtain a stretched multilayer polyethylene substrate with a thickness of 25 μm.

An image was formed on the corona discharge treated surface of the stretched multilayer polyethylene substrate prepared above by gravure printing using a solvent-based gravure ink (Finart, manufactured by DIC Graphics).

[A3. Preparation of polyethylene-based laminate]
The stretched multilayer polyethylene substrate and the polyethylene sealant film obtained in the Examples or Comparative Examples were laminated together via a 3.5 μm-thick adhesive layer made of a two-component curing polyurethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-77T/H-7) so that the image-forming surface of the stretched multilayer polyethylene substrate faced the aluminum vapor-deposited film-forming surface of the polyethylene sealant film obtained in the Examples or Comparative Examples, thereby obtaining a polyethylene laminate.

[B1. Preparation of polypropylene sealant film]
[Example 2-1]
The EVOH, maleic acid modified polypropylene, PP1, PP2, PP3 and blended polypropylene A prepared above were extruded by a cast film forming method to produce a 6-layer film of gas barrier resin layer (3.2 μm)/adhesive resin layer (3.2 μm)/PP1 layer (3.2 μm)/PP2 layer (18.4 μm)/PP3 layer (8.8 μm)/blend polypropylene A layer (3.2 μm), and an unstretched polypropylene film with a total thickness of 40 μm was produced. The numbers in parentheses indicate the thickness of the layers.

A 60 nm thick aluminum vapor deposition film was formed on the gas barrier resin layer of the unstretched polypropylene film by PVD to obtain a polypropylene laminate film. The optical density (OD value) of the vapor deposition film was measured and found to be 3.0. This polypropylene laminate film was used as a sealant film.

[Example 2-2]
An unstretched polypropylene film and a polypropylene-based laminate film were produced in the same manner as in Example 2-1, except that the resin constituting the gas barrier resin layer was changed to the Ny prepared above.

[Comparative Example 2-1]
A 40 μm-thick unstretched polypropylene film consisting of one PP layer was produced by a cast film-forming method. A polypropylene-based film was produced in the same manner as in Example 2-1, except that this unstretched polypropylene film was used. An aluminum vapor deposition film was formed on the one PP layer.

[Comparative Example 2-2]
An unstretched polypropylene film having a total thickness of 40 μm and including a PP1 layer (36.8 μm)/blended polypropylene A layer (3.2 μm) was produced by a cast film production method. The numbers in parentheses indicate the thickness of the layers. A polypropylene-based laminated film was produced in the same manner as in Example 2-1, except that this unstretched polypropylene film was used. An aluminum vapor deposition film was formed on the PP1 layer.

[B2. Preparation of polypropylene-based laminate]
A 20 μm-thick biaxially stretched polypropylene film (manufactured by Toyobo Co., Ltd., product name: P2171) was prepared as a polypropylene resin substrate, one side of which was corona discharge treated. An image was formed on the corona discharge treated surface of the biaxially stretched polypropylene film by gravure printing using a solvent-based gravure ink (manufactured by DIC Graphics Corporation, Finart).

The polypropylene resin substrate and the polypropylene sealant film obtained in the examples or comparative examples were laminated together via a 3.5 μm thick adhesive layer made of a two-component curing polyurethane adhesive (manufactured by Rock Paint, product name: RU-77T/H-7) so that the image-forming surface of the polypropylene resin substrate faced the aluminum vapor deposition film-forming surface of the polypropylene sealant film obtained in the examples or comparative examples, to obtain a polypropylene laminate.

[C1. Preparation of polyethylene-based intermediate substrate]
[Example 3-1]
The EVOH, maleic acid modified polyethylene, blended polyethylene A and blended polyethylene B prepared above were extruded by a cast film forming method to produce a 6-layer film having a gas barrier resin layer (2.0 μm)/adhesive resin layer (3.0 μm)/blend polyethylene A layer (2.0 μm)/blend polyethylene B layer (10.0 μm)/blend polyethylene B layer (5.5 μm)/blend polyethylene B layer (2.5 μm) and a total thickness of 25 μm. The numbers in parentheses indicate the thickness of the layers.

A 60 nm thick aluminum vapor deposition film was formed on the gas barrier resin layer of the unstretched polyethylene film by PVD to obtain a polyethylene laminate film. The optical density (OD value) of the vapor deposition film was measured and found to be 3.0. This polyethylene laminate film was used as an intermediate substrate.

[Example 3-2]
An unstretched polyethylene film and a polyethylene-based laminate film were produced in the same manner as in Example 3-1, except that the resin constituting the gas barrier resin layer was changed to the Ny prepared above.

[Comparative Example 3-1]
A 25 μm-thick unstretched polyethylene film consisting of an LLDPE (1) layer was produced by a cast film-forming method. A polyethylene film was produced in the same manner as in Example 3-1, except that this unstretched polyethylene film was used. An aluminum vapor deposition film was formed on the LLDPE (1) layer.

[C2. Preparation of sealant film]
The blended polyethylene A, blended polyethylene B, blended polyethylene C and blended polyethylene D prepared above were extruded into 6 layers by a cast film forming method to produce an unstretched polyethylene film having a total thickness of 40 μm, including blended polyethylene A layer (3.2 μm) / blended polyethylene A layer (3.2 μm) / blended polyethylene B layer (3.2 μm) / blended polyethylene B layer (18.4 μm) / blended polyethylene C layer (8.8 μm) / blended polyethylene D layer (3.2 μm). The numbers in parentheses indicate the thickness of the layers. This unstretched polyethylene film was used as a sealant film.

[C3. Preparation of stretched multilayer polyethylene substrate]
In the same manner as above, an image-formed stretched multi-layer polyethylene substrate was prepared.

[C4. Preparation of polyethylene-based laminate]
The stretched multilayer polyethylene substrate and the polyethylene-based intermediate substrate obtained in the Examples or Comparative Examples were laminated together via a 3.5 μm thick adhesive layer made of a two-component curing polyurethane adhesive (manufactured by Rock Paint, product name: RU-77T/H-7) so that the image forming surface of the stretched multilayer polyethylene substrate faced the aluminum vapor deposition film forming surface of the polyethylene-based intermediate substrate obtained in the Examples or Comparative Examples.
Furthermore, the surface of the polyethylene intermediate substrate on which the aluminum vapor deposition film was not formed and the blended polyethylene A layer surface of the sealant film prepared above were laminated together with a 3.5 μm thick adhesive layer made of a two-component curing polyurethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-77T/H-7) interposed therebetween to obtain a polyethylene laminate.

[D1. Preparation of polypropylene-based intermediate substrate]
[Example 4-1]
The EVOH, maleic acid-modified polypropylene, PP1, and PP2 prepared above were extruded by a cast film forming method to produce a 6-layer film of gas barrier resin layer (2.0 μm)/adhesive resin layer (3.0 μm)/PP1 layer (2.0 μm)/PP2 layer (10.0 μm)/PP2 layer (5.5 μm)/PP1 layer (2.5 μm) and a total thickness of 25 μm. The numbers in parentheses indicate the thickness of the layers.

A 60 nm thick aluminum vapor deposition film was formed on the gas barrier resin layer of the unstretched polypropylene film by PVD to obtain a polypropylene laminate film. The optical density (OD value) of the vapor deposition film was measured and found to be 3.0. This polypropylene laminate film was used as an intermediate substrate.

[Example 4-2]
An unstretched polypropylene film and a polypropylene-based laminate film were produced in the same manner as in Example 4-1, except that the resin constituting the gas barrier resin layer was changed to the Ny prepared above.

[Comparative Example 4-1]
A 25 μm-thick unstretched polypropylene film consisting of one PP layer was produced by a cast film-forming method. A polypropylene-based film was produced in the same manner as in Example 4-1, except that this unstretched polypropylene film was used. An aluminum vapor deposition film was formed on the one PP layer.

[D2. Preparation of sealant film]
The PP1, PP2, PP3 and blended polypropylene A prepared above were extruded into 6 layers by a cast film forming method to produce an unstretched polypropylene film having a total thickness of 40 μm, including PP1 layer (3.2 μm) / PP1 layer (3.2 μm) / PP1 layer (3.2 μm) / PP2 layer (18.4 μm) / PP3 layer (8.8 μm) / blended polypropylene A layer (3.2 μm). The numbers in parentheses indicate the thickness of the layers. This unstretched polypropylene film was used as a sealant film.

[D3. Preparation of polypropylene-based laminate]
A 20 μm-thick biaxially stretched polypropylene film (manufactured by Toyobo Co., Ltd., product name: P2171) was prepared as a polypropylene resin substrate, one side of which was corona discharge treated. An image was formed on the corona discharge treated surface of the biaxially stretched polypropylene film by gravure printing using a solvent-based gravure ink (manufactured by DIC Graphics Corporation, Finart).

The polypropylene resin substrate and the polypropylene-based intermediate substrate obtained in the Examples or Comparative Examples were laminated together via a 3.5 μm thick adhesive layer made of a two-component curing polyurethane adhesive (manufactured by Rock Paint, product name: RU-77T/H-7) so that the image forming surface of the polypropylene resin substrate faced the aluminum vapor deposition film forming surface of the polypropylene-based intermediate substrate obtained in the Examples or Comparative Examples.
Furthermore, the PP1 layer surface (the surface on which the aluminum vapor deposition film was not formed) of the polypropylene-based intermediate substrate and the PP1 layer surface of the sealant film prepared above were laminated together with a 3.5 μm thick adhesive layer made of a two-component curing polyurethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-77T/H-7) interposed therebetween to obtain a polypropylene-based laminate.

[Oxygen Barrier Property Evaluation]
The laminated films (polyethylene or polypropylene sealant film, polyethylene or polypropylene intermediate substrate) obtained in the examples and comparative examples were cut to A4 size, and the oxygen permeability (cc/m2/day/atm) was measured in an environment of 23°C and 90% relative humidity using an oxygen permeability measuring device (OXTRAN2/ ^20, manufactured by MOCON Corporation, USA) in accordance with JIS K7126-2:2006. The measurement results are shown in Tables 1 to 4.

[Water vapor barrier property evaluation]
The laminated films obtained in the examples and comparative examples were cut to A4 size, and the water vapor permeability (g/ ^m2 /day) was measured in an environment of a temperature of 40°C and a relative humidity of 90% using a water vapor permeability measuring device (PERMATRAN3/31, manufactured by MOCON Corporation, USA) in accordance with JIS K7129-2: 2019. The measurement results are shown in Tables 1 to 4.

[Heat sealability test]
The laminates obtained in the Examples and Comparative Examples were cut to a size of 10 cm x 10 cm to prepare sample pieces. The sample pieces were folded in half so that the sealant layer (sealant film) was on the inside, and a 1 cm x 10 cm area was heat-sealed at a temperature of 130°C (for polyethylene-based laminates) or 150°C (for polypropylene-based laminates) under a pressure of 1 kgf/ ^cm2 for 1 second.

After heat sealing, the sample pieces were cut into strips 15 mm wide, and both ends that were not heat sealed were held in a tensile tester (Orientec, RTC-1310A) and the peel strength (N/15 mm) was measured in accordance with JIS Z0238:1998 at a speed of 300 mm/min, a peel angle of 90°, and a load range of 50 N. The measurement results are shown in Tables 1 to 4.

[Film appearance]
In Examples 2-1 and 4-1, no formation of aggregates (streaks) was observed at both ends in the TD direction of the unstretched polypropylene film produced. When maleic acid-modified polypropylene (Admer QF551T) was used instead of maleic acid-modified polypropylene (Admer AT3351E) in Examples 2-1 and 4-1, formation of aggregates was observed at both ends in the TD direction of the unstretched polypropylene film produced.

REFERENCE SIGNS LIST 1: Laminate 10: Laminated film 12: Polyolefin resin layer 12a: First resin layer 12b: Second resin layer 12c: Third resin layer 12d: Fourth resin layer 13: Adhesive resin layer 14: Gas barrier resin layer 15: Vapor deposition film 20: Polyolefin resin substrate 30: Adhesive layer 40: Sealant layer

Claims (14)

A polyolefin resin layer;
An adhesive resin layer;
A gas barrier resin layer;
In this order,
The adhesive resin layer contains an acid-modified resin as a main component,
The gas barrier resin layer contains at least one resin selected from an ethylene-vinyl alcohol copolymer and a polyamide.
Laminated film. The laminate film according to claim 1, which is an unstretched cast film. The laminated film according to claim 1, wherein the gas barrier resin layer is a layer containing an ethylene-vinyl alcohol copolymer as a main component, a layer containing a polyamide as a main component, or a layer containing a mixed resin of an ethylene-vinyl alcohol copolymer and a polyamide as a main component. The laminated film according to claim 1, wherein the ethylene-vinyl alcohol copolymer has an ethylene-derived structural unit content of 30 mol% or more and 60 mol% or less, and a melt flow rate (MFR) of 0.1 g/10 min or more and 5 g/10 min or less. The laminated film according to claim 1, wherein the acid-modified resin is an acid-modified polyolefin. The laminated film according to claim 5, wherein the acid-modified polyolefin is at least one selected from acid-modified polyethylene and acid-modified polypropylene. the polyolefin resin layer is a polypropylene resin layer containing polypropylene as a main component, the adhesive resin layer contains acid-modified polypropylene as a main component, and the gas barrier resin layer is a layer containing an ethylene-vinyl alcohol copolymer as a main component,
The laminate film according to claim 1, wherein in the adhesive resin layer, the ratio (intensity 1/intensity 2) of the intensity 1 of the peak attributable to C=O stretching vibration in the region of 1700 to 1800 cm ^-1 and the intensity 2 of the peak attributable to C-H bending vibration in the region of 1400 to 1500 cm ^-1 , as measured by an attenuated total reflection (ATR) measurement method using an infrared spectrophotometer, is less than 0.4. The laminated film according to claim 7, wherein the ethylene-vinyl alcohol copolymer has an ethylene-derived structural unit content of 30 mol% or more and 60 mol% or less, a melt flow rate (MFR) of 0.1 g/10 min or more and 5 g/10 min or less, and an MFR of the acid-modified polypropylene of 1 g/10 min or more and 15 g/10 min or less. The laminated film according to claim 1, wherein the polyolefin resin layer is a polyethylene resin layer containing polyethylene as a main component, or a polypropylene resin layer containing polypropylene as a main component. The laminated film according to claim 1, wherein the polyolefin resin layer comprises a first resin layer containing a polyolefin and a second resin layer containing a polyolefin and a heat seal modifier, and the second resin layer constitutes one of the surface layers of the laminated film. The laminated film according to claim 1, further comprising a vapor-deposited film provided on the gas barrier resin layer. The laminated film according to claim 1, which is used as the sealant layer constituting a packaging material having a substrate and a sealant layer. The laminated film according to claim 1, which is used as the substrate constituting a packaging material having a substrate and a sealant layer. The laminated film according to claim 1, which is used as the intermediate substrate constituting a packaging material having a polyolefin resin substrate, an intermediate substrate, and a sealant layer in this order.