JP7823319B2 - Laminate and packaging container - Google Patents

Description

The present invention relates to a laminate and a packaging container.

Laminates made of multiple films stacked together are used as components for packaging containers such as pouches. The laminates include a base material and a sealant film.

Packaging containers are sometimes required to have barrier properties against oxygen, water vapor, etc. For example, Patent Document 1 proposes forming an aluminum vapor-deposited layer on the surface of a sealant film.

Japanese Patent Application Laid-Open No. 2001-179878

Heat sealing is a known method for producing packaging containers using laminates. For example, the inner surfaces of a laminate are joined by heat sealing. This produces pouches such as pillow pouches. In heat sealing, heat is applied to the outer surface of the laminate. The heat transferred from the outer surface to the inner surface melts the sealant film, joining the inner surfaces of the laminate.

If the sealant film has low heat resistance, it may deform during the heat sealing process, resulting in a deterioration of the barrier properties of the laminate. On the other hand, if the sealant film has high heat resistance, the workability of the heat sealing process will decrease.

The present invention aims to provide a laminate that can effectively solve these problems.

The present invention provides a laminate comprising, in order from the outside to the inside, at least a substrate, an adhesive layer, a vapor deposition layer, and a sealant layer,
the sealant layer includes a first resin layer in contact with the vapor-deposited layer, and a second resin layer located inside the first resin layer and containing polyolefin;
The laminate is such that the melting point of the first resin layer is higher than the melting point of the second resin layer.

In the laminate of the present invention, the adhesive layer may be an adhesive layer.

In the laminate of the present invention, the adhesive layer may contain a cured product of a composition containing a polyester polyol and an isocyanate compound.

In the laminate of the present invention, the substrate may include a paper substrate layer, and the paper substrate layer may have a basis weight of 20 g/m ² or more and 120 g/m ² or less.

In the laminate of the present invention, the weight ratio of the paper base layer in the laminate may be greater than 50%.

In the laminate of the present invention, the first resin layer may contain a resin material having a polar group.

In the laminate of the present invention, the resin material may be one or more resin materials selected from the group consisting of ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyester, nylon 6, nylon 6,6, MXD nylon, and amorphous nylon.

In the laminate of the present invention, the second resin layer may contain one or more polyolefins selected from the group consisting of polypropylene and polyethylene.

In the laminate of the present invention, the vapor-deposited layer may include an aluminum vapor-deposited layer.

The laminate of the present invention may have a tear strength of 1500 mN or more.

The laminate of the present invention may have a breaking energy of 520 J or more.

The present invention is a packaging container comprising the laminate described above.

The present invention can improve the barrier properties of the laminate.

FIG. 2 is a cross-sectional view showing an example of a laminate. FIG. 2 is a cross-sectional view showing an example of a laminate. FIG. 2 is a cross-sectional view showing an example of a laminate. FIG. 1 is a cross-sectional view showing an example of a barrier film. FIG. 2 is a plan view showing a test piece for measuring tear strength. FIG. 1 is a diagram showing an example of a packaging container. FIG. 2 is a cross-sectional view showing the layer structure of a barrier film B. FIG. 2 is a cross-sectional view showing the layer structure of a barrier film C. FIG. 1 is a diagram showing evaluation results of examples and comparative examples. FIG. 1 is a diagram showing an example of a laminate in which a crack has occurred.

An embodiment of the present invention will be described. Note that in the drawings accompanying this specification, the scale and aspect ratios have been appropriately altered and exaggerated from those of the actual product for the sake of clarity and ease of understanding.

Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "orthogonal" and "identical," as well as values of length and angle, are not bound by strict meanings, but are interpreted to include the range within which similar functions can be expected.

In this specification, when two or more upper limit value candidates and two or more lower limit value candidates are listed for a certain parameter, the numerical range of that parameter may be constructed by combining any one upper limit value candidate with any one lower limit value candidate. For example, consider the following description: "Parameter B may be, for example, A1 or more and may be A2 or more. Parameter B may be, for example, A3 or less and may be A4 or less." In this case, the numerical range of parameter B may be A1 or more and A3 or less, A1 or more and A4 or less, A2 or more and A3 or less, or A2 or more and A4 or less.

(Laminate)
FIG. 1 is a cross-sectional view showing an example of a laminate 50 according to the present embodiment. The laminate 50 includes an inner surface 50x and an outer surface 50y. The inner surface 50x is a surface that is joined by heat sealing. The outer surface 50y is located opposite the inner surface 50x. The laminate 50 includes, in order from the outside to the inside, a substrate 40, an adhesive layer 45, and a barrier film 10. In the example shown in FIG. 1, the substrate 40 forms the outer surface 50y.

The barrier film 10 includes a sealant layer 20 and a vapor-deposited layer 30. The sealant layer 20 includes a first surface 20x and a second surface 20y. The first surface 20x is located on the inner side. In the example shown in FIG. 1, the first surface 20x constitutes the inner surface 50x. The second surface 20y is located on the opposite side of the first surface 20x. The vapor-deposited layer 30 is located on the second surface 20y. The sealant layer 20 includes a first resin layer 21 and a second resin layer 22. The first resin layer 21 constitutes the second surface 20y and is in contact with the vapor-deposited layer 30. The second resin layer 22 is located on the inner side of the first resin layer 21. The second resin layer 22 may constitute the first surface 20x.

The layer structure of the laminate 50 in the example shown in FIG. 1 is expressed as follows, from the outside to the inside:
Substrate/adhesive layer/vapor-deposited layer/first resin layer/second resin layer. "/" represents the boundary between two adjacent layers.

Figure 2 is a cross-sectional view showing another example of a laminate 50 according to this embodiment. The laminate 50 may include a printed layer 41 located on the outer side of the substrate 40. The printed layer 41 may form the outer surface 50y.

The layer structure of the laminate 50 in the example shown in FIG. 2 is expressed as follows, from the outside to the inside:
Printing layer/base material/adhesive layer/vapor deposition layer/first resin layer/second resin layer

Figure 3 is a cross-sectional view showing another example of a laminate 50 according to this embodiment. The sealant layer 20 may include a third resin layer 23 located between the first resin layer 21 and the second resin layer 22.

The layer structure of the laminate 50 in the example shown in FIG. 3 is expressed as follows, from the outside to the inside:
Base material / adhesive layer / vapor deposition layer / first resin layer / third resin layer / second resin layer

The layer structure of the laminate 50 is arbitrary, as long as the laminate 50 includes, from outside to inside, at least the substrate 40, adhesive layer 45, vapor deposition layer 30, and sealant layer 20. The laminate 50 according to this embodiment may have a layer structure other than those shown in Figures 1 to 3. For example, the laminate 50 may include a third resin layer 23 shown in Figure 3 in addition to the layer structure shown in Figure 2.

The thickness of the laminate 50 is, for example, 50 μm or more, or may be 60 μm or more, or 80 μm or more. The thickness of the laminate 50 is, for example, 200 μm or less, or may be 150 μm or less, or may be 100 μm or less.

Each layer of the laminate 50 will be described in detail below.

[Base material]
The substrate 40 is a layer that imparts strength, such as rigidity, to the laminate 50. The substrate 40 may include paper. Examples of the paper include kraft paper, fine paper, and coated paper. The kraft paper may be unbleached kraft paper. In other words, the color of the kraft paper may be brown.

The basis weight of the paper of the substrate 40 is set so that the weight ratio of paper in the laminate 50 is greater than 50%. This allows the laminate 50 and the packaging container to be classified as paper for recycling. The basis weight of the paper is, for example, 20 g/ ^m2 or more, or may be 30 g/ ^m2 or more, or 40 g/ ^m2 or more. The basis weight of the paper is, for example, 120 g/ ^m2 or less, or may be 100 g/ ^m2 or less, or may be 80 g/ ^m2 or less.

The weight ratio of paper in the laminate 50 may be 51% or more, or 60% or more. The weight ratio of paper in the laminate 50 may be 95% or less, 90% or less, or 80% or less.

[Sealant layer]
The sealant layer 20 is made of, for example, a sealant film. The sealant film is a film produced by, for example, co-extrusion of the resin material constituting the first resin layer 21 and the resin material constituting the second resin layer 22. Co-extrusion methods include the T-die method and the inflation method. The sealant film is preferably an unstretched film. The term "unstretched" refers not only to a film that is not stretched at all, but also to a film that is slightly stretched due to the tension applied during film formation.

The thickness of the sealant layer 20 is, for example, 25 μm or more, or may be 30 μm or more, or 40 μm or more. The thickness of the sealant layer 20 is, for example, 70 μm or less, or may be 60 μm or less, or may be 50 μm or less.

The thickness of the sealant layer 20 may be determined in relation to the basis weight of the paper of the substrate 40. The ratio of the thickness of the sealant layer 20 to the basis weight of the paper is, for example, 0.25 μm/(g/ ^m2 ) or more, or 0.40 μm/(g/ ^m2 ) or more, or 0.50 μm/(g/ ^m2 ) or more. The ratio of the thickness of the sealant layer 20 to the basis weight of the paper is, for example, 0.95 μm/(g/ ^m2 ) or less, or 0.90 μm/(g/ ^m2 ) or less, or 0.85 μm/(g/ ^m2 ) or less.

Each layer of the sealant layer 20 will now be described. First, the second resin layer 22 will be described.

The second resin layer 22 contains a polymer synthesized using an olefin such as ethylene or propylene as a monomer. For example, the second resin layer 22 contains a polyolefin such as polyethylene or polypropylene as a main component. "Main component" means that the weight ratio of polyolefin in the second resin layer 22 is 51% or more. The weight ratio of polyolefin in the second resin layer 22 may be 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more.

The second resin layer 22 may be a polypropylene resin layer containing polypropylene as a main component. The weight ratio of polypropylene in the second resin layer 22 may be 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more.

The polypropylene contained in the second resin layer 22 may be either a homopolymer or a copolymer. The copolymer may be either a block copolymer or a random copolymer.

A block copolymer is a copolymer having a polymer block made of propylene and a polymer block made of an α-olefin other than propylene. For example, a block copolymer may contain a polymer block made of ethylene, butene-1, 4-methyl-1-pentene, etc. in addition to a polymer block made of propylene. For example, a block copolymer may be a propylene-ethylene block copolymer. The structural formula of a propylene-ethylene block copolymer is shown in Formula (I).

A random copolymer is a random copolymer containing propylene and an α-olefin other than propylene. For example, a random copolymer contains, in addition to propylene, ethylene, butene-1, 4-methyl-1-pentene, etc. For example, a random copolymer includes a propylene-ethylene random copolymer. The structural formula of a propylene-ethylene random copolymer is shown in formula (II). The random copolymer may also include a terpolymer.

A homopolymer is a polymer of only propylene. The structural formula of a propylene homopolymer is shown in formula (III).

Homopolymers have higher crystallinity than random polymers. When rigidity, heat resistance, etc. are important, it is preferable to use homopolymers. When impact resistance, sealing ability, etc. are important, it is preferable to use random copolymers or block copolymers.

The second resin layer 22 may contain biomass-derived polypropylene. The second resin layer 22 may also contain mechanically recycled or chemically recycled polypropylene.

The second resin layer 22 may be a polyethylene resin layer containing polyethylene as a main component. The weight ratio of polyethylene in the second resin layer 22 may be 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. The second resin layer 22 may contain one or more types of polyethylene selected from the group consisting of high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE).

High-density polyethylene is polyethylene having a density of 0.942 g/ ^cm3 or more. Medium-density polyethylene is polyethylene having a density of 0.930 g/ ^cm3 or more and less than 0.942 g/ ^cm3 . Low-density polyethylene is polyethylene having a density of 0.910 g/ ^cm3 or more and less than 0.930 g/ ^cm3 .

The density of resins, layers, films, etc. is measured in accordance with Method B (pycnometer method) or Method D (density gradient tube method) of JIS K7112:1999. Method B or Method D is selected appropriately depending on the shape and mass of the test piece to be measured. When Method D is selected, the measurement temperature (liquid temperature) is 23°C.

Linear polyethylene is a copolymer of ethylene and an α-olefin polymerized using a multi-site catalyst, such as a Ziegler-Natta catalyst, or a single-site catalyst, such as a metallocene catalyst. Linear polyethylene is distinguished from ethylene homopolymers. The α-olefins used as monomers in linear polyethylene have three or more carbon atoms. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 4-methylpentene, 3,3-dimethylbutene, and mixtures thereof. Linear polyethylene with a density of less than 0.930 g/ ^cm3 may also be referred to as linear low-density polyethylene (LLDPE).

The thickness of the second resin layer 22 is, for example, 20 μm or more, or may be 25 μm or more, or 30 μm or more. The thickness of the second resin layer 22 is, for example, 60 μm or less, or may be 50 μm or less, or may be 40 μm or less.

The second resin layer 22 may be composed of a single layer containing polyolefin. The second resin layer 22 may also have two or more layers containing polyolefin. Figure 4 is a cross-sectional view showing an example of a barrier film 10 including a second resin layer 22. A film constituting a sealant layer 20 including a second resin layer 22 containing two or more layers is produced, for example, by co-extrusion of two or more materials constituting the second resin layer 22 and the material constituting the first resin layer 21.

As shown in FIG. 4, the second resin layer 22 may include a first layer 22a, a second layer 22b, and a third layer 22c arranged from the inside to the outside. The first layer 22a may constitute the first surface 20x.

The first layer 22a, the second layer 22b, and the third layer 22c include polyolefin. The first layer 22a, the second layer 22b, and the third layer 22c may include polypropylene. The first layer 22a, the second layer 22b, and the third layer 22c may include polyethylene. One or more of the first layer 22a, the second layer 22b, and the third layer 22c may include polypropylene and polyethylene. For example, the first layer 22a may include polypropylene and polyethylene. For example, the first layer 22a may include polypropylene and HDPE.

The weight ratio of polyethylene in the first layer 22a may be higher than the weight ratio of polyethylene in the second layer 22b and the third layer 22c. The second layer 22b and the third layer 22c may not contain polyethylene. In this way, the distribution of polyethylene in the first resin layer 21 may be biased toward the first surface 20x.

Next, the first resin layer 21 will be described. The first resin layer 21 has a higher melting point than the second resin layer 22. This prevents deformation of the second surface 20y of the sealant layer 20 during the heat-sealing process. Deformation of the second surface 20y occurs, for example, when part of the material of the sealant layer 20 heated during the heat-sealing process flows, causing the thickness of the sealant layer 20 to locally decrease. Such deformation is likely to occur, for example, at the boundary between the sealed and unsealed portions of a packaging container (described below) made from the laminate 50.

The vapor-deposited layer 30 is in contact with the second surface 20y. When the vapor-deposited layer 30 deforms in response to deformation of the second surface 20y, contact between the second surface 20y and the vapor-deposited layer 30 is maintained. However, the rigidity of the vapor-deposited layer 30 is generally higher than that of the sealant layer 20. For this reason, a large amount of deformation may result in the vapor-deposited layer 30 being unable to deform in response to deformation of the second surface 20y. In this case, the vapor-deposited layer 30 may partially peel off from the second surface 20y, or cracks may occur in the vapor-deposited layer 30 or the second surface 20y. Peeling or cracks may reduce the barrier properties of the laminate 50. For example, the water vapor permeability and oxygen permeability of the laminate 50 may increase. If the laminate 50 is used to make a packaging container, the contents may leak from the packaging container.

In this embodiment, as described above, the melting point T1 of the first resin layer 21 is higher than the melting point T2 of the second resin layer 22. This makes it possible to prevent deformation of the second surface 20y during the heat sealing process, compared to when the sealant layer 20 is composed only of the second resin layer 22. This also makes it possible to prevent peeling and cracking of the laminate 50. This improves the barrier properties of the laminate 50.

The difference between the melting point T1 and the melting point T2 is, for example, 5°C or more, and may be 10°C or more, 15°C or more, 20°C or more, or 30°C or more. This prevents deformation of the second surface 20y during the heat sealing process. The difference between the melting point T1 and the melting point T2 may be 130°C or less, 110°C or less, 90°C or less, 80°C or less, or 70°C or less.

The melting point T2 of the second resin layer 22 is, for example, 70° C. or higher, or may be 80° C. or higher, or 90° C. or higher. The melting point T2 may be 190° C. or lower, or 180° C. or lower, or 170° C. or lower.
The melting point T1 of the first resin layer 21 is, for example, 150° C. or higher, or may be 160° C. or higher, or 170° C. or higher. The melting point T1 may be 260° C. or lower, or may be 240° C. or lower, or may be 230° C. or lower.

The melting point is calculated by analyzing the sealant layer 20 using a differential scanning calorimeter in accordance with JIS K7121:2012. For the analysis, a sample containing the sealant layer 20 is collected. The sample may be collected from the sealant layer 20 in the laminate 50, from the sealant layer 20 in the barrier film 10, or from the sealant film that constitutes the sealant layer 20. The sample weighs approximately 5 mg.

A sample for measuring the melting point of the first resin layer 21 is obtained, for example, by scraping the sealant layer 20 from the second surface 20y side. A sample for measuring the melting point of the second resin layer 22 is obtained, for example, by scraping the sealant layer 20 from the first surface 20x side.

For analysis, the sample is placed in an aluminum cell. Then, under a nitrogen atmosphere, the sample is heated from 20°C to the holding temperature at a heating rate of 10°C/min. The holding temperature is a temperature sufficiently higher than the melting point, for example, 250°C. The sample is then heated at the holding temperature for 10 minutes. The sample is then cooled from the holding temperature to 20°C at a heating rate of 10°C/min. This heating, holding, and cooling process is repeated once more. The differential scanning calorimeter that can be used is, for example, a thermal analyzer from Hitachi High-Tech Science Corporation's TA7000 series.

The first resin layer 21 may contain a resin material having polar groups. In this case, the vapor deposition layer 30 is more likely to adhere to the first resin layer 21, i.e., the second surface 20y. This improves the barrier properties of the barrier film 10.

A polar group refers to a group containing one or more heteroatoms. Examples of polar groups include ester groups, epoxy groups, hydroxyl groups, amino groups, amide groups, carboxyl groups, carbonyl groups, carboxylic anhydride groups, sulfone groups, thiol groups, and halogen groups. Preferably, the polar group is a hydroxyl group, ester group, amino group, amide group, carboxyl group, or carbonyl group, with a hydroxyl group being particularly preferred.

The resin material of the first resin layer 21 is, for example, an ethylene-vinyl alcohol copolymer, polyvinyl alcohol, or polyamide resin. Polyamide resins include nylon 6, nylon 6,6, MXD nylon, and amorphous nylon. The resin material of the first resin layer 21 is preferably an ethylene-vinyl alcohol copolymer or polyamide resin.

The first resin layer 21 may contain additives, as long as the adhesion of the vapor deposition layer 30 to the first resin layer 21 is not impaired. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants (slip agents), UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

The ratio of the thickness of the first resin layer 21 to the thickness of the sealant layer 20 is, for example, 1% or more, or alternatively, 3% or more, or 5% or more. This improves the adhesion of the vapor deposition layer 30 to the sealant layer 20. This improves the barrier properties of the barrier film 10. It also improves the lamination strength of a laminate including the barrier film 10.

The ratio of the thickness of the first resin layer 21 to the thickness of the sealant layer 20 is, for example, 20% or less, or may be 15% or less, or even 10% or less. This improves the film-forming and processing suitability of the sealant film that constitutes the sealant layer 20. It also improves the recyclability of the barrier film 10 and the recyclability of a laminate that includes the barrier film 10.

The thickness of the first resin layer 21 is, for example, 1 μm or more, or may be 2 μm or more, or 3 μm or more. The thickness of the first resin layer 21 is, for example, 6 μm or less, or may be 5 μm or less.

Next, the third resin layer 23 will be described. The third resin layer 23 contains a resin that bonds the first resin layer 21 and the second resin layer 22 together. By providing the third resin layer 23, it is possible to improve adhesion between the first resin layer 21 and the second resin layer 22.

The third resin layer 23 may contain an adhesive resin such as polyether, polyester, silicone resin, epoxy resin, polyurethane, vinyl resin, phenolic resin, or polyolefin. Preferably, the third resin layer 23 contains polyolefin and an acid-modified product thereof. When the second resin layer 22 is a polypropylene resin layer, the third resin layer 23 preferably contains polypropylene and an acid-modified product thereof. This allows the proportion of polypropylene in the barrier film 10 to be increased.
The third resin layer 23 may contain commercially available polypropylene or an acid-modified product thereof. For example, the third resin layer 23 may contain the Admer series manufactured by Mitsui Chemicals, Inc.

The thickness of the third resin layer 23 is, for example, 1 μm or more, or may be 2 μm or more, or 3 μm or more. This allows for greater adhesion between the first resin layer 21 and the second resin layer 22. The thickness of the third resin layer 23 is, for example, 15 μm or less, or may be 10 μm or less, or 5 μm or less. This allows for greater processability of the film that constitutes the sealant layer 20.

[Vapour-deposited layer]
The vapor deposition layer 30 includes a metal layer or an inorganic oxide layer. The vapor deposition layer 30 is impermeable to gases such as oxygen and water vapor. Therefore, the barrier film 10 and the laminate described below can have barrier properties such as oxygen barrier property and water vapor barrier property. This can prevent the weight of the contents from decreasing in a packaging container made of the laminate. Furthermore, when a metal layer is used, it can prevent light from passing through the laminate and reaching the contents. This can prevent oxidation of components of the contents, such as oil.

The metal layer may include a metal such as aluminum. For example, the metal layer may include a layer of aluminum vapor-deposited on the second surface 20y of the sealant layer 20.

The inorganic oxide layer may contain inorganic oxides such as aluminum oxide (alumina), silicon oxide (silica), magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide, and silicon carbide oxide (carbon-containing silicon oxide). Preferably, the inorganic oxide layer contains silica, silicon carbide oxide, or alumina.

The thickness of the vapor-deposited layer 30 is, for example, 1 nm or more, or may be 5 nm or more, or 10 nm or more. This can further improve the barrier properties of the barrier film 10. The thickness of the vapor-deposited layer 30 can be 150 nm or less, 100 nm or less, or 80 nm or less. This can prevent defects such as cracks from occurring in the vapor-deposited layer 30. It can also improve the recyclability of the laminate and packaging container.

The vapor deposition layer 30 may consist of a single layer, or may include two or more layers. A single layer is a layer formed by a single vapor deposition process. Two or more layers are formed by two or more vapor deposition processes. The materials constituting the two or more layers may be the same or different. The methods for forming the two or more layers may be the same or different.

[Adhesive layer]
The adhesive layer 45 is a layer that bonds the substrates including the substrate 40 to the barrier film 10. The adhesive layer 45 may be an adhesive agent layer or an adhesive resin layer.

The adhesive layer contains at least one adhesive. The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be a solvent-free adhesive or a solvent-based adhesive. From the viewpoint of environmental impact, a solvent-free adhesive is preferred.
Examples of solvent-free adhesives include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives.
Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives.

In the process of manufacturing a packaging container using a laminate 50 having a vapor deposition layer 30, a bending load may be applied to the laminate 50. In this case, damage such as cracks may occur in the vapor deposition layer 30. Preferably, the adhesive is configured to suppress the occurrence of damage or to repair damage. For example, the adhesive includes a cured product of a composition containing a polyester polyol and an isocyanate compound. This can improve the barrier properties of the laminate 50, such as the oxygen barrier property and water vapor barrier property.

The glass transition temperature of the cured product of the composition containing polyester polyol and isocyanate compound is, for example, -30°C or higher, or may be 0°C or higher, or 25°C or higher. This improves the oxygen barrier properties, water vapor barrier properties, and laminate strength of the laminate 50. The glass transition temperature is calculated by differential scanning calorimetry (DSC) in accordance with JIS K 7121:2012.

Polyester polyols have two or more hydroxyl groups as functional groups in each molecule. Also, isocyanate compounds have two or more isocyanate groups as functional groups in each molecule. Polyester polyols have, for example, a polyester structure or a polyester polyurethane structure as their main skeleton.

A specific example of a composition (adhesive) containing polyester polyol and an isocyanate compound is the PASLIM series manufactured by DIC Corporation.

The composition containing a polyester polyol and an isocyanate compound may further contain a phosphate ester, a plate-like inorganic compound, a coupling agent, cyclodextrin and/or its derivatives, etc.

Examples of polyester polyols having two or more hydroxyl groups in one molecule as functional groups include the following [Example 1] to [Example 3].
[Example 1] Polyester polyol obtained by polycondensation of ortho-oriented polycarboxylic acid or its anhydride with polyhydric alcohol. [Example 2] Polyester polyol having a glycerol skeleton. [Example 3] Polyester polyol having an isocyanuric ring.

The polyester polyol according to the first example is a polycondensate obtained by polycondensing a polycarboxylic acid component containing at least one or more kinds of orthophthalic acid and its anhydride with a polyhydric alcohol component.
In particular, polyester polyols in which the content of orthophthalic acid and its anhydride relative to the total amount of polycarboxylic acid components is 70 to 100% by mass are preferred.

The polyester polyol according to the first example essentially contains orthophthalic acid and its anhydride as the polycarboxylic acid component. Other polycarboxylic acid components may be copolymerized within a range that does not impair the effects of the present embodiment.
Examples of other polycarboxylic acid components include aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid; unsaturated bond-containing polycarboxylic acids such as maleic anhydride, maleic acid, and fumaric acid; alicyclic polycarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, anhydrides of these dicarboxylic acids, and ester-forming derivatives of these dicarboxylic acids; and polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids. Of these, succinic acid, 1,3-cyclopentanedicarboxylic acid, and isophthalic acid are preferred.
Two or more of the above other polycarboxylic acids may be used.

The polyhydric alcohol component is, for example, an aliphatic polyhydric alcohol, an aromatic polyhydric alcohol, or the like.
Examples of aliphatic polyhydric alcohols include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, cyclohexanedimethanol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol.
Examples of aromatic polyhydric alcohols include hydroquinone, resorcinol, catechol, naphthalenediol, biphenol, bisphenol A, bisphenol F, tetramethylbiphenol, ethylene oxide-extended products of these, and hydrated aliphatic compounds of these.
The polyhydric alcohol component may contain at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol.

The polyester polyol according to the second example is, for example, a polyester polyol having a glycerol skeleton represented by general formula (1).
In general formula (1), R ₁ , R ₂ and R ₃ are each independently H (hydrogen atom) or a group represented by the following general formula (2).

In formula (2), n represents an integer of 1 to 5, X represents an arylene group selected from the group consisting of 1,2-phenylene groups, 1,2-naphthylene groups, 2,3-naphthylene groups, 2,3-anthraquinonediyl groups, and 2,3-anthracenediyl groups, which may have a substituent, and Y represents an alkylene group having 2 to 6 carbon atoms, provided that at least one of R ₁ , R ₂ , and R ₃ represents a group represented by general formula (2).

In general formula (1), at least one of R ₁ , R ₂ and R ₃ must be a group represented by general formula (2). In particular, it is preferable that all of R ₁ , R ₂ and R ₃ are groups represented by general formula (2).

The polyester polyol may contain _a mixture of two or more of _{the following} compounds: a compound in which any one of R ₁ , R ₂ , and R ₃ is a group represented by general formula (2); a compound in which any two of R ₁ , R ₂ , and R ₃ are groups represented by general formula (2); and a compound in which all of R 1 , R 2 , and R 3 are groups represented by general formula (2).

X represents an arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group, which may have a substituent.
When X is substituted with a substituent, it may be substituted with one or more substituents. The substituent is bonded to any carbon atom on X that is different from the free radical. Examples of the substituent include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

In general formula (2), Y represents an alkylene group having 2 to 6 carbon atoms, such as ethylene, propylene, butylene, neopentylene, 1,5-pentylene, 3-methyl-1,5-pentylene, 1,6-hexylene, methylpentylene, and dimethylbutylene. Among these, propylene and ethylene are preferred, and ethylene is most preferred.

The polyester resin compound having a glycerol skeleton represented by general formula (1) can be synthesized, for example, by reacting glycerol with an aromatic polycarboxylic acid or its anhydride in which a carboxylic acid is substituted at the ortho position, and a polyhydric alcohol component as essential components.

Examples of aromatic polycarboxylic acids or anhydrides in which a carboxylic acid is substituted at the ortho position include orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracenecarboxylic acid or anhydride.
These compounds may have a substituent on any carbon atom of the aromatic ring, such as a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, or a naphthyl group.

The polyhydric alcohol component is, for example, an alkylene diol having 2 to 6 carbon atoms. Examples of diols that can be used include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, and dimethylbutanediol.

The polyester polyol according to the third example is a polyester polyol having an isocyanuric ring represented by the following general formula (3).
In general formula (3), R ₁ , R ₂ and R ₃ each independently represent "-(CH ₂ )n1-OH (wherein n1 represents an integer of 2 to 4)" or a structure of general formula (4).

In general formula (4), n2 represents an integer of 2 to 4, and n3 represents an integer of 1 to 5. X represents an arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group, which may have a substituent. Y represents an alkylene group having 2 to 6 carbon atoms. However, at least one of R ₁ , R ₂ , and R ₃ is a group represented by general formula (4).

In the general formula (3), the alkylene group represented by —(CH ₂ )n1— may be linear or branched. Among these, n1 is preferably 2 or 3, and most preferably 2.

In general formula (4), n2 represents an integer from 2 to 4, and n3 represents an integer from 1 to 5. X represents an optionally substituted arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group.

When X is substituted with a substituent, it may be substituted with one or more substituents. The substituent is bonded to any carbon atom on X that is different from the free radical. Examples of the substituent include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.
The substituent for X is preferably a hydroxyl group, a cyano group, a nitro group, an amino group, a phthalimido group, a carbamoyl group, an N-ethylcarbamoyl group, or a phenyl group, and most preferably a hydroxyl group, a phenoxy group, a cyano group, a nitro group, a phthalimido group, or a phenyl group.

In general formula (4), Y represents an alkylene group having 2 to 6 carbon atoms, such as an ethylene group, a propylene group, a butylene group, a neopentylene group, a 1,5-pentylene group, a 3-methyl-1,5-pentylene group, a 1,6-hexylene group, a methylpentylene group, or a dimethylbutylene group. Among these, a propylene group and an ethylene group are preferred, and an ethylene group is most preferred.

In general formula (3), at least one of R ₁ , R ₂ and R ₃ is a group represented by general formula (4). In particular, it is preferable that all of R ₁ , R ₂ and R ₃ are groups represented by general formula (4).

The polyester polyol may contain _a mixture of two or more of _{the following} compounds: a compound in which any one of R ₁ , R ₂ , and R ₃ is a group represented by general formula (4); a compound in which any two of R ₁ , R ₂ , and R ₃ are groups represented by general formula (4); and a compound in which all of R 1 , R 2 , and R 3 are groups represented by general formula (4).

The polyester polyol having an isocyanuric ring represented by general formula (3) is synthesized by reacting a triol having an isocyanuric ring, an aromatic polycarboxylic acid or its anhydride in which a carboxylic acid is substituted at the ortho position, and a polyhydric alcohol component as essential components.

Triols having an isocyanuric ring include, for example, alkylene oxide adducts of isocyanuric acid, such as 1,3,5-tris(2-hydroxyethyl)isocyanuric acid and 1,3,5-tris(2-hydroxypropyl)isocyanuric acid.

Aromatic polycarboxylic acids or anhydrides in which the carboxylic acid is substituted at the ortho position include, for example, orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracenecarboxylic acid or anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring.

Substituents include, for example, chloro, bromo, methyl, ethyl, i-propyl, hydroxyl, methoxy, ethoxy, phenoxy, methylthio, phenylthio, cyano, nitro, amino, phthalimido, carboxyl, carbamoyl, N-ethylcarbamoyl, phenyl, and naphthyl groups.

The polyhydric alcohol component is, for example, an alkylene diol having 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, and dimethylbutanediol.
Among these, polyester polyol compounds having an isocyanuric ring, which use 1,3,5-tris(2-hydroxyethyl)isocyanuric acid or 1,3,5-tris(2-hydroxypropyl)isocyanuric acid as the triol compound having an isocyanuric ring, orthophthalic anhydride as the aromatic polycarboxylic acid or its anhydride in which the carboxylic acid is substituted at the ortho position, and ethylene glycol as the polyhydric alcohol, are particularly excellent in oxygen barrier properties and adhesiveness and are therefore preferred.

Isocyanuric rings are highly polar and trifunctional, which can increase the polarity of the entire system and increase the crosslink density. From this perspective, it is preferable for the adhesive resin to contain 5% or more by mass of isocyanuric rings relative to the total solids content.

The isocyanate compound has two or more isocyanate groups in the molecule.
The isocyanate compound may be aromatic or aliphatic, and may be a low molecular weight compound or a high molecular weight compound.
The isocyanate compound may be a blocked isocyanate compound obtained by addition reaction using a known isocyanate blocking agent by a known, conventional appropriate method.
Among these, from the viewpoints of adhesiveness and retort resistance, polyisocyanate compounds having three or more isocyanate groups are preferred, and from the viewpoints of oxygen barrier property and water vapor barrier property, aromatic compounds are preferred.

Examples of the isocyanate compound include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, metaxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds, as well as adducts, biurets, and allophanates obtained by reacting these isocyanate compounds with low-molecular-weight active hydrogen compounds or alkylene oxide adducts thereof, or high-molecular-weight active hydrogen compounds.
Examples of low molecular weight active hydrogen compounds include ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, metaxylylenediamine, etc. Examples of molecular weight active hydrogen compounds include polymeric active hydrogen compounds of various polyester resins, polyether polyols, and polyamides.

The adhesive layer formed of a cured product of a composition containing a polyester polyol and an isocyanate compound may contain a phosphoric acid-modified compound, for example, a compound represented by the following general formula (5) or (6):
In general formula (5), R ₁ , R ₂ , and R ₃ are groups selected from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a (meth)acryloyl group, a phenyl group which may have a substituent, and an alkyl group having 1 to 4 carbon atoms which has a (meth)acryloyloxy group. At least one of _{R 1} , R ₂ , and R ₃ is a hydrogen atom. n represents an integer of 1 to 4.
_R4 and _R5 are groups selected from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a (meth)acryloyl group, a phenyl group which may have a substituent, and an alkyl group having 1 to 4 carbon atoms and having a (meth)acryloyloxy group. n represents an integer of 1 to 4, x represents an integer of 0 to 30, and y represents an integer of 0 to 30. Either x or y is greater than 0.

Examples of phosphate-modified compounds include phosphoric acid, pyrophosphoric acid, triphosphoric acid, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, dibutyl phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, isododecyl acid phosphate, butoxyethyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, and polyoxyethylene alkyl ether phosphate. The adhesive layer may contain one or more of these compounds.

The content of the phosphoric acid-modified compound in the adhesive layer containing a polyester polyol and an isocyanate compound is, for example, 0.005% by mass, or may be 0.01% by mass or more, and the content of the phosphoric acid-modified compound is, for example, 10% by mass or less, or may be 1% by mass or less.
By setting the content of the phosphate-modified compound to 0.005% by mass or more, the oxygen barrier property and water vapor barrier property can be improved, and by setting the content of the phosphate-modified compound to 10% by mass or less, the adhesiveness of the adhesive layer can be improved.

The adhesive layer containing a polyester polyol and an isocyanate compound may contain a plate-like inorganic compound. This can improve the oxygen barrier property, water vapor barrier property, and adhesiveness of the adhesive layer. It can also improve the flex resistance of the laminate 50.
Examples of the plate-like inorganic compounds include kaolinite-serpentine group clay minerals (halloysite, kaolinite, endelite, dickite, nacrite, antigorite, chrysotile, etc.) and pyrophyllite-talc group (pyrophyllite, talc, keroli, etc.).

Examples of the coupling agent include a silane-based coupling agent, a titanium-based coupling agent, and an aluminum-based coupling agent represented by the following general formula (7). These coupling agents may be used alone or in combination of two or more.

Examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxytrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β( N-beta (aminoethyl) gamma-aminopropylmethyldimethoxysilane, N-beta (aminoethyl) gamma-aminopropyltrimethoxysilane, N-beta (aminoethyl) gamma-aminopropyltriethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, gamma-chloropropyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-triethoxysilyl-N-(1,3-dimethylbutylidene).

Examples of titanium-based coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraoctyl bis(didodecyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctainol titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl isostearoyl diacryl titanate, diisostearoyl ethylene titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and dicumyl phenyloxyacetate titanate.

Examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate, diisopropoxyaluminum ethylacetoacetate, diisopropoxyaluminum monomethacrylate, isopropoxyaluminum alkylacetoacetate mono(dioctylphosphate), aluminum 2-ethylhexanoate oxide trimer, aluminum stearate oxide trimer, and alkylacetoacetate aluminum oxide trimer.

The adhesive layer formed from the composition containing polyester polyol and an isocyanate compound may contain cyclodextrin and/or a derivative thereof, which can enhance the adhesiveness of the adhesive layer and the flex resistance of the laminate 50.
Examples of cyclodextrin and/or its derivatives include cyclodextrin, alkylated cyclodextrin, acetylated cyclodextrin, and hydroxyalkylated cyclodextrin, in which the hydrogen atoms of the hydroxyl groups of the glucose units of cyclodextrin are substituted with other functional groups. Branched cyclic dextrins may also be used. The cyclodextrin skeleton in cyclodextrin and cyclodextrin derivatives may be any of α-cyclodextrin consisting of six glucose units, β-cyclodextrin consisting of seven glucose units, and γ-cyclodextrin consisting of eight glucose units.
These compounds may be used alone or in combination of two or more. These cyclodextrins and/or their derivatives may be collectively referred to as dextrin compounds.

From the viewpoint of compatibility and dispersibility in the adhesive layer containing a polyester polyol and an isocyanate compound, it is preferable to use a cyclodextrin derivative as the cyclodextrin compound.
In view of the polarity of the various resins, the degree of substitution may be, for example, 0.1 or more per glucose unit or 0.3 or more per glucose unit, and may be, for example, 14 or less per glucose unit or 8 or less per glucose unit.

Examples of alkylated cyclodextrins include methyl-α-cyclodextrin, methyl-β-cyclodextrin, and methyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

Acetylated cyclodextrins include, for example, monoacetyl-α-cyclodextrin, monoacetyl-β-cyclodextrin, and monoacetyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

Hydroxyalkylated cyclodextrins include, for example, hydroxypropyl-α-cyclodextrin, hydroxypropyl-β-cyclodextrin, and hydroxypropyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

The thickness of the adhesive layer is, for example, 0.5 μm or more, or may be 0.8 μm or more, or 1.0 μm or more, which can improve the adhesiveness of the adhesive layer and the flex resistance of the laminate 50.
The thickness of the adhesive layer is, for example, 6 μm or less, or may be 5 μm or less, or may be 4.5 μm or less, which can improve the processability of the laminate 50. Furthermore, it can improve the recyclability of the laminate 50 and the packaging container.

The adhesive layer is formed, for example, by a dry lamination method in which an adhesive is used to bond the substrate and the barrier film 10. For example, the adhesive layer is formed by applying an adhesive to one surface of the substrate or the barrier film 10 and then drying it. Examples of application methods include direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine coating, and transfer roll coating.

Next, the adhesive resin layer will be described. The adhesive resin layer contains a thermoplastic resin. The adhesive resin layer is formed by, for example, melt extrusion lamination or sand lamination. The thermoplastic resin is, for example, a polyolefin resin, a cyclic polyolefin resin, or a copolymer resin, modified resin, or mixture containing these resins as the main component.
Examples of polyolefin resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, and ionomer resins. Acid-modified polyolefin resins obtained by modifying polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid may also be used. Resins obtained by graft-polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, or ester monomers with polyolefin resins may also be used. One of these materials may be used alone, or two or more of them may be used in combination.
Examples of cyclic polyolefin resins include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. One of these materials may be used alone, or two or more may be used in combination.

The thickness of the adhesive resin layer is, for example, 5 μm or more, or may be 10 μm or more, or 15 μm or more. The thickness of the adhesive resin layer is, for example, 50 μm or less, or may be 40 μm or less, or may be 30 μm or less.

[Printing layer]
The printing layer 41 has a printed pattern such as letters, numbers, pictures, figures, symbols, and designs. The printing layer 41 is provided for decoration, indication of contents, indication of expiration date, indication of manufacturer, seller, etc., and for imparting aesthetic appeal. The printing layer 41 may be provided over the entire surface of the substrate 40, or may be provided only on a part of it. The printing layer 41 may contain a pigment or a dye.

The thickness of the printed layer 41 is, for example, 0.5 μm or more, or may be 0.8 μm or more, or 1.0 μm or more. The thickness of the printed layer 41 is, for example, 6 μm or less, or may be 5 μm or less, or 4.5 μm or less.

(Method for manufacturing laminate)
Next, a method for manufacturing the barrier film 10 will be described.

First, a sealant film that will form the sealant layer 20 is prepared. For example, the material that will form the first resin layer 21 and the material that will form the second resin layer 22 are extruded together using a T-die method, inflation method, or the like. This allows the sealant film to be produced.

Next, a vapor deposition layer 30 is formed on the sealant film. This results in a barrier film 10 comprising the sealant layer 20 and the vapor deposition layer 30.

The deposition layer 30 can be formed by any known method. For example, physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition (CVD) methods such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition, can be used.

Also, a substrate 40 is prepared. A printing layer 41 may be provided on the substrate 40.

Next, a lamination process is carried out in which the substrate 40 and the barrier film 10 are laminated via the adhesive layer 45.

When the adhesive layer 45 is an adhesive layer, the adhesive is first applied to either the substrate 40 or the barrier film 10. After the adhesive has dried, the substrate 40 and the barrier film 10 are laminated together using a dry lamination method.

When the adhesive layer 45 is an adhesive resin layer, the substrate 40 and the barrier film 10 are laminated, for example, by sand lamination. For example, the material of the adhesive resin layer in a molten state is extruded between the substrate 40 and the barrier film 10. This bonds the barrier film 10 to the substrate 40.

(Effect of laminate)
In this embodiment, the melting point of the first resin layer 21 of the sealant layer 20 is higher than the melting point of the second resin layer 22. This makes it possible to suppress deformation of the second surface 20y during the heat sealing process, compared to when the sealant layer 20 is composed of only the second resin layer 22. This makes it possible to suppress peeling and cracking of the laminate 50. This improves the barrier properties of the laminate 50.

The oxygen permeability of the laminate 50 before being processed into a packaging container is, for example, 0.50 cc/m2 ^day atm or less, and may be 0.40 cc/ ^m2 day atm or less, or 0.30 cc/ ^m2 day atm or less. The oxygen permeability is measured in accordance with JIS K 7126 at a temperature of 23°C and a relative humidity of 90% RH. A MOCON oxygen permeability measuring device manufactured by Hitachi High-Tech Science is used as the oxygen permeability measuring device.

The water vapor permeability of the laminate 50 before being processed into a packaging container is, for example, 0.50 g/ ^m2 ·day or less, and may be 0.40 g/ ^m2 ·day or less, or even 0.30 g/ ^m2 ·day. The water vapor permeability is measured in accordance with JIS K 7129 at a temperature of 40°C and a relative humidity of 90% RH. A MOCON water vapor permeability measuring device manufactured by Hitachi High-Tech Science is used as a water vapor permeability measuring device.

However, the thermal conductivity of paper is lower than that of plastic. Therefore, when the substrate 40 includes paper, heat applied to the outer surface 50y of the laminate 50 is less likely to be transmitted to the inner surface. This increases the time required for the heat sealing process, reducing productivity. Reducing the thickness of the paper is one way to increase productivity. However, reducing the thickness of the paper reduces the weight ratio of paper in the laminate 50, making it impossible to maintain the paper classification for recycling.
In this embodiment, the melting point of the second resin layer 22 of the sealant layer 20 is lower than the melting point of the first resin layer 21. This makes it easier for the first surface 20x of the sealant layer 20 to melt during the heat-sealing process. This prevents the time required for heat-sealing from increasing even when the substrate 40 contains paper. This allows for increased productivity of packaging containers while maintaining the paper classification for recycling.

The laminate 50 may have high tear strength. The tear strength of the laminate 50 in at least one direction may be, for example, 1500 mN or more, 2000 mN or more, 2500 mN or more, or 3000 mN or more. For example, the tear strength of the laminate 50 in the perpendicular direction may be 1500 mN or more, 2000 mN or more, 2500 mN or more, or 3000 mN or more. The perpendicular direction is the direction perpendicular to the machine direction, known as the transverse direction (TD). The machine direction is the direction in which the film flows when it is molded, known as the machine direction (MD). The tear strength of the laminate 50 in the machine direction may be, for example, 900 mN or more, 1000 mN or more, 1100 mN or more, or 1200 mN or more.

Tear strength is measured by the Elmendorf tear method in accordance with JIS-K7128-B. The IM-702 manufactured by Tester Sangyo Co., Ltd. can be used as the measuring instrument. Figure 5 is a plan view of a test specimen 70 used to measure tear strength. The test specimen 70 includes a slit 71 extending in the measurement direction. When measuring tear strength in the perpendicular direction, the slit 71 extends in the perpendicular direction. When measuring tear strength in the machine direction, the slit 71 extends in the machine direction. The length L3 of the slit 71 is, for example, 20 mm. The dimension L1 of the test specimen 70 in the direction in which the slit 71 extends is, for example, 63 mm. The dimension L2 of the test specimen 70 in the direction perpendicular to the direction in which the slit 71 extends is, for example, 75 mm. The measurement was performed in an environment with a temperature of 23°C and a relative humidity of 50% RH.

The laminate 50 may have impact resistance. For example, the laminate 50 may have a high breaking energy. The breaking energy of the laminate 50 may be, for example, 520 J or more, or 550 J or more, or even 600 J or more.

The measuring device used to measure the fracture energy of the laminate 50 is the Tester Sangyo Film Impact Tester BU-302. Specifically, the hammer of the film impact tester impacts a test piece of the laminate 50 under tension. The strength at which the test piece breaks is measured. A 3J hammer is used. The diameter of the impact ball at the tip of the hammer is 12.7 mm. The lift angle of the hammer is 90°. The test piece has an effective dimensional area consisting of a circle with a diameter of 35 mm. For example, the shape of the test piece is a 100 mm square. During measurement, the test piece is held in a chuck and an impact is applied to the effective dimensional area of the test piece with the hammer. The measurement environment is a temperature of 23°C and a relative humidity of 50% RH.

(packaging container)
The packaging container of this embodiment includes the laminate 50 described above. The packaging container is, for example, a bag. The bag is also called a pouch. The bag may have any shape. For example, various shapes may be adopted, such as a standing type, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a palm seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type.

As an example of a packaging container, a pillow seal bag will be described. In the example shown in Figure 6, the packaging container 60 includes a front surface 61 and a back surface 62 formed from a laminate 50. Both the front surface 61 and the back surface 62 are formed by folding back a single laminate 50. Although not shown, the number of laminates 50 forming the packaging container 60 is not limited to one. The packaging container 60 may be formed from two or more laminates 50.

The packaging container 60 has a first end 63, a second end 64 opposing the first end 63 in the first direction D1, and a pair of side ends 65 extending along the first direction D1 from the first end 63 to the second end 64. The first direction D1 may be the direction in which the laminate 50 is transported during the manufacturing process of the laminate 50 and the packaging container 60. In other words, the first direction D1 may be the flow direction described above. In this case, the second direction D2 is the vertical direction described above.

In the example shown in FIG. 6, the first end 63 and the second end 64 extend in a second direction D2 perpendicular to the first direction D1, giving the packaging container 60 a rectangular outer shape. Although not shown, the first end 63 and the sixth end 14 may extend in a direction inclined relative to the second direction D2.

The dimension M1 of the packaging container 60 in the first direction D1 is, for example, 50 mm or more, or may be 70 mm or more, or 100 mm or more. The dimension M1 is, for example, 300 mm or less, or may be 250 mm or less, or may be 200 mm or less.
The dimension M2 of the packaging container 60 in the second direction D2 is, for example, 15 mm or more, or may be 20 mm or more, or 25 mm or more. The dimension M2 is, for example, 100 mm or less, or may be 80 mm or less, or may be 60 mm or less.

As shown in FIG. 6 , the packaging container 60 has a gable portion 67 extending along the first direction D1 from the first end 63 to the second end 64 between a pair of side ends 65. The gable portion 67 may be located approximately in the center of the packaging container 60 in the second direction D2. The laminate 50 is stacked at the gable portion 67.

The packaging container 60 has a seal portion that joins the inner surfaces 50x of the laminate 50 together. The seal portion includes a first end seal portion 631 located at the first end 63, a second end seal portion 641 located at the second end 64, and a seam seal portion 671 located at the seam 67. The first end seal portion 631 and the second end seal portion 641 join the inner surface 50x of the laminate 50 that forms the front surface 61 and the inner surface 50x of the laminate 50 that forms the back surface 62.

The packaging container 60 has an unsealed portion 68 located between the first end seal portion 631 and the second end seal portion 641 in the first direction D1. In the unsealed portion 68, the inner surfaces 50x of the laminate 50 are not joined together. The unsealed portion 68 contains the contents.

The contents may be liquid, powder, or gel. The contents may be food or non-food.

According to this embodiment, the melting point of the first resin layer 21 of the sealant layer 20 is higher than the melting point of the second resin layer 22. This prevents deformation of the second surface 20y during the heat sealing process. This prevents defects such as pinholes from occurring in the sealed portions 631, 641, and 671. This also prevents the vapor deposition layer 30 from peeling off from the sealant layer 20. This prevents a decrease in the barrier properties of the packaging container 60. For example, this prevents the contents from leaking from the packaging container 60.

As shown by the dotted line in Figure 6, test specimen 70 may be prepared by cutting out laminate 50 constituting packaging container 60. For example, test specimen 70 can be obtained by removing the contents from packaging container 60 and then cutting out laminate 50 constituting packaging container 60. Test specimen 70 may be used to measure tear strength. Test specimen 70 may be used to measure breaking energy. Test specimen 70 may be used to measure oxygen permeability. Test specimen 70 may be used to measure water vapor permeability.

The oxygen permeability and water vapor permeability of the test piece 70 obtained from the laminate 50 that constitutes the packaging container 60 that contained the contents may be different from the oxygen permeability and water vapor permeability of the laminate 50 in its state before it is processed into a packaging container.
The oxygen permeability of the test piece 70 obtained from the laminate 50 constituting the packaging container 60 that contained the contents is, for example, 50 cc/ ^m2 ·day·atm or less, or may be 30 cc/ ^m2 ·day·atm or less, or 20 cc/ ^m2 ·day·atm or less, or may be 10 cc/ ^m2 ·day·atm or less.
The water vapor permeability of the test piece 70 obtained from the laminate 50 constituting the packaging container 60 that contained the contents is, for example, 3.50 g/ ^m2 ·day or less, or may be 2.00 g/ ^m2 ·day or less, 1.00 g/ ^m2 ·day or less, or may be 0.50 g/ ^m2 ·day or less.

It should be noted that various modifications can be made to the above-described embodiment. Below, modifications will be described, with reference to the drawings as necessary. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described embodiment will be designated by the same reference numerals as those used for the corresponding parts in the above-described embodiment, and duplicate explanations will be omitted. Furthermore, if it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified embodiment, the explanation of those effects may be omitted.

(Modification of the substrate)
In the above-described embodiment, an example in which the substrate 40 includes paper has been described, but this is not limiting. The substrate 40 may include at least one biaxially stretched plastic film. The substrate 40 may include only one biaxially stretched plastic film, or only two biaxially stretched plastic films. The substrate 40 may also include three or more biaxially stretched plastic films.

A biaxially stretched plastic film is a film made of plastic that has been stretched in two specific directions. A biaxially stretched plastic film is a plastic film that has been intentionally stretched to improve the mechanical strength of the plastic film. The stretching direction of a biaxially stretched plastic film is not particularly limited. For example, a biaxially stretched plastic film may be stretched in the first direction D1 and the second direction D2 in Figure 6. The stretching ratio of a biaxially stretched plastic film is, for example, 1.05 times or more.

The biaxially stretched plastic film may contain polyester. Examples of polyester include polyethylene terephthalate (hereinafter also referred to as PET) and polybutylene terephthalate (hereinafter also referred to as PBT). The polyester in the biaxially stretched plastic film may be composed of one type of polyester or two or more types of polyester. The polyester content in the biaxially stretched plastic film 51 may be 51% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more. For example, the PET content in the biaxially stretched plastic film may be 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more.

The biaxially stretched plastic film may contain polyamide as a primary component. Examples of polyamides include aliphatic polyamides and aromatic polyamides. Aliphatic polyamides include nylons such as nylon-6, nylon-6,6, and copolymers of nylon 6 and nylon 6,6, while aromatic polyamides include polymetaxylene adipamide (MXD6). The polyamide content in the biaxially stretched plastic film may be 51% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more.

The thickness of the biaxially stretched plastic film is, for example, 8 μm or more, or may be 9 μm or more, or 12 μm or more. The thickness of the biaxially stretched plastic film 51 is, for example, 30 μm or less, or may be 25 μm or less, or may be 20 μm or less.

The present invention will be explained in more detail below using examples, but the present invention is not limited to the following examples.

(Example P1)
A barrier unstretched polypropylene film manufactured by Kencar was prepared as the barrier film 10. The unstretched polypropylene film manufactured by Kencar includes a first resin layer 21 and a second resin layer 22, and is provided with a sealant layer 20 formed by co-extrusion and a vapor deposition layer 30. The first resin layer 21 contains nylon 6 as a main component. The second resin layer 22 contains polypropylene as a main component. The vapor deposition layer 30 is an aluminum layer. In the following description, the barrier unstretched polypropylene film manufactured by Kencar will also be referred to as "barrier film A."

(Example P2)
As a barrier film, VM-CPP2703 manufactured by Toray Advanced Film, designated by reference symbol 10B in FIG. 7, was prepared. As shown in FIG. 7, VM-CPP2703 includes a second resin layer 22 and a vapor-deposited layer 30, but does not include a first resin layer 21. The second resin layer 22 contains polypropylene. The vapor-deposited layer 30 is an aluminum layer. In the following description, VM-CPP2703 will also be referred to as "barrier film B."

(Example P3)
A barrier film, Sun Mirror CP-VR manufactured by Liko Co., Ltd., designated by the reference symbol 10C in FIG. 8, was prepared. As shown in FIG. 8, Sun Mirror CP-VR includes a second resin layer 22, a primer layer 25, and a vapor deposition layer 30, but does not include a first resin layer 21. The second resin layer 22 includes a first layer 21a, a second layer 21b, and a third layer 21c. The first layer 21a includes polypropylene and polyethylene. The second layer 21b and the third layer 21c include polypropylene. The second resin layer 22 is obtained by co-extrusion of the materials for the first layer 21a, the second layer 21b, and the third layer 21c. The primer layer 25 is formed by applying a solution containing the material for the primer layer 25 onto the film obtained by co-extrusion. The vapor deposition layer 30 is an aluminum layer. In the following description, Sun Mirror CP-VR is also referred to as "barrier film C."

Example 1
A laminate 50 was produced by dry laminating the substrate 40 and the barrier film A via the adhesive layer 45. The substrate 40 was made of Tokai Kraft C, an unbleached kraft paper manufactured by Tokushu Tokai Paper Co., Ltd. The basis weight of the substrate 40 was 50 g/ ^m² . The thickness of the barrier film A was 40 μm. PASLIM manufactured by DIC was used as the adhesive constituting the adhesive layer 45. PASLIM comprises a composition containing a polyester polyol and an isocyanate compound. Specifically, PASLIM contains a base agent VM001 and a curing agent VM080CP manufactured by DIC. The adhesive application amount was 3 g/ ^m² . In the following description, Tokai Kraft C will also be referred to as Kraft paper A, and PASLIM will also be referred to as adhesive A. The weight ratio of paper in the laminate 50 was 56%.

The layer structure of the laminate 50 of Example 1 is expressed as follows:
Kraft paper A/Adhesive A/VM-AL/Ny/Polyolefin A
The leftmost layer is the layer that forms the outer surface 50y of the laminate 50. The rightmost layer is the layer that forms the inner surface 50x of the laminate 50.
"VM-AL" means a vapor-deposited aluminum layer. "Polyolefin A" means the second resin layer 22 of the barrier film A.

Example 2
A laminate 50 was produced by dry laminating a substrate 40 and a barrier film A via an adhesive layer 45. Taio Atlas, an unbleached kraft paper manufactured by Daio Paper Corporation, was used as the substrate 40. The basis weight of the substrate 40 was 50 g/ ^m² . The thickness of the barrier film A was 40 µm. PASLIM manufactured by DIC was used as the adhesive constituting the adhesive layer 45. The amount of adhesive applied was 3 g/ ^m² . In the following description, Taio Atlas will also be referred to as kraft paper B. The weight ratio of paper in the laminate 50 was 56%.

The layer structure of the laminate 50 of Example 2 is expressed as follows:
Kraft paper B / adhesive A / VM-AL / Ny / polyolefin A

(Comparative Example 1)
A laminate 50 was produced in the same manner as in Example 1, except that barrier film B was used as the barrier film 10. The thickness of barrier film B was 40 μm. The weight ratio of paper in the laminate 50 was 56%.

The layer structure of the laminate 50 of Comparative Example 1 is expressed as follows:
Kraft paper A/adhesive A/VM-AL/polyolefin B
"Polyolefin B" means the second resin layer 22 of the barrier film B.

(Comparative Example 2)
A laminate 50 was produced in the same manner as in Example 1, except that barrier film C was used as the barrier film 10. The thickness of barrier film C was 40 μm. The weight ratio of paper in the laminate 50 was 56%.

The layer structure of the laminate 50 of Comparative Example 2 is expressed as follows:
Kraft paper A/Adhesive A/VM-AL/Primer/Polyolefin C
"Primer" refers to the primer layer 25. "Polyolefin C" refers to the second resin layer 22 of the barrier film C.

(Comparative Example 3)
A laminate 50 was produced in the same manner as in Comparative Example 2, except that Kraft paper B was used as the substrate 40. The weight ratio of paper in the laminate 50 was 56%.

The layer structure of the laminate 50 of Comparative Example 3 is expressed as follows:
Kraft paper B / Adhesive A / VM-AL / Primer / Polyolefin C

(Comparative Example 4)
Except for using a 30 μm thick barrier film B, a laminate 50 was produced in the same manner as in Comparative Example 1. The weight ratio of paper in the laminate 50 was 63%.

The layer structure of the laminate 50 of Comparative Example 4 is expressed as follows.
Kraft paper A/adhesive A/VM-AL/polyolefin B

(Comparative Example 5)
Except for using the 30 μm thick barrier film C, the laminate 50 was produced in the same manner as in Comparative Example 2. The weight ratio of paper in the laminate 50 was 63%.

The layer structure of the laminate 50 of Comparative Example 5 is expressed as follows:
Kraft paper A/Adhesive A/VM-AL/Primer/Polyolefin C

[Measurement of tear strength]
The tear strength of the laminates 50 of Examples 1 and 2 and Comparative Examples 1 to 5 was measured in accordance with JIS-K7128-B at a temperature of 23°C and a relative humidity of 50% RH. The measuring instrument used was an IM-702 manufactured by Tester Sangyo Co., Ltd. The tear strength in the machine direction (MD) and the transverse direction (TD) was measured for five test pieces each. The average value of the measurement results for the five test pieces is shown in Figure 9.

[Measurement of Breaking Energy]
The breaking energy of the laminates 50 of Examples 1 and 2 and Comparative Examples 1 to 5 was measured in an environment of a temperature of 23°C and a relative humidity of 50% RH. A film impact tester BU-302 manufactured by Tester Sangyo Co., Ltd. was used as the breaking energy measuring device. The breaking energy was measured for five test pieces. The average values of the measurement results are shown in FIG.

[Measurement of oxygen permeability]
Using test pieces made from the laminate 50 in a state before being processed into a packaging container, the oxygen permeability was measured in an environment of a temperature of 23°C and a relative humidity of 90% RH in accordance with JIS K 7126. A MOCON oxygen permeability measuring device manufactured by Hitachi High-Tech Science was used as the oxygen permeability measuring device. In the measurement, the test pieces of the laminate 50 were positioned so that the substrate 40 was located on the oxygen supply side. The oxygen permeability was measured for five test pieces. The average value of the measurement results is shown in the "Before filling" column in Figure 9.

[Measurement of water vapor permeability]
Using test pieces made from the laminate 50 in a state before being processed into a packaging container, the water vapor permeability was measured in an environment of a temperature of 40°C and a relative humidity of 90% RH in accordance with JIS K 7129. A MOCON water vapor permeability measuring device manufactured by Hitachi High-Tech Science was used as the water vapor permeability measuring device. In the measurement, the test pieces of the laminate 50 were positioned so that the substrate 40 was located on the water vapor supply side. The water vapor permeability was measured for five test pieces. The average value of the measurement results is shown in the "Before filling" column in Figure 9.

[Leak evaluation]
The laminates 50 of Examples 1 and 2 and Comparative Examples 1 to 5 were heat-sealed to produce packaging containers 60 as shown in FIG. 6 . A TYTT-type vertical pillow filling machine manufactured by Tokyo Jido Kikai Seisakusho was used as the heat-sealing device. The number of shots was 85 rpm, and the sealing temperature for the vertical seal was 150°C, and the sealing temperature for the horizontal seal was 160°C. The packaging containers 60 were filled with a check liquid. Ageless Seal Check Liquid manufactured by Mitsubishi Gas Chemical Company, Inc. was used as the check liquid. After filling with the check liquid, the packaging containers 60 were left in an environment with a temperature of 23°C and a relative humidity of 50% RH for 24 hours. Thereafter, it was confirmed whether or not there was leakage of the check liquid. The results are shown in the "Leakage" column of FIG. 9 . "OK" means that no leakage occurred. "NG" means that leakage occurred.

[Crack evaluation]
The laminates 50 of Examples 1 and 2 and Comparative Examples 1 to 5 were heat-sealed to produce the packaging containers 60 shown in FIG. 6 . A TYTT-type vertical pillow filling machine manufactured by Tokyo Jido Kikai Seisakusho was used as the heat-sealing device. The number of shots was 85 rpm, the sealing temperature of the vertical seal (the seam seal 671) was 150°C, and the sealing temperature of the horizontal seals (the first end seal 631 and the second end seal 641) was 160°C. Next, the cross section of the laminate 50 was observed using an optical microscope at the intersection of the vertical seal and the horizontal seal to check for cracks. The results are shown in the "Crack" column of FIG. 9 . "OK" means that no cracks were present. "NG" means that cracks were present. A cross-sectional photograph of an example in which cracks were present is shown in FIG. 10 . It can be seen that cracks were present in the thickness direction of the sealant layer 20 at the boundary between the sealed portion 55 and the non-sealed portion 56.

[Measurement of oxygen permeability]
Using test pieces made from the laminate 50 of the packaging container 60 that had contained the contents, the oxygen permeability was measured in an environment of 23°C and 90% RH in accordance with JIS K 7126. The contents were cookies. The measurement conditions were the same as those for the laminate 50 before being processed into the packaging container 60. The oxygen permeability was measured for five test pieces. The average value of the measurement results is shown in the "After filling" column in Figure 9. The oxygen permeability "after filling" was higher than the oxygen permeability "before filling". In Examples 1 and 2, the difference between the oxygen permeability "after filling" and the oxygen permeability "before filling" was smaller than in Comparative Examples 1 to 5.

[Measurement of water vapor permeability]
Using test pieces made from the laminate 50 of the packaging container 60 that had contained the contents, the water vapor permeability was measured in an environment of 40°C and 90% RH in accordance with JIS K 7129. The contents were cookies. The measurement conditions were the same as those for the laminate 50 before being processed into the packaging container 60. The water vapor permeability was measured for five test pieces. The average value of the measurement results is shown in the "After filling" column in Figure 9. The water vapor permeability "after filling" was higher than the water vapor permeability "before filling". In Examples 1 and 2, the difference between the water vapor permeability "after filling" and the water vapor permeability "before filling" was smaller than in Comparative Examples 1 to 5.

10 Barrier film 20 Sealant layer 20x First surface 20y Second surface 21 First resin layer 22 Second resin layer 22a First layer 22b Second layer 22c Third layer 23 Third resin layer 30 Vapor deposition layer 40 Substrate 41 Printed layer 45 Adhesive layer 50 Laminate 50x Inner surface 50y Outer surface 55 Sealed portion 56 Non-sealed portion 57 Crack 60 Packaging container 61 Surface 62 Back surface 63 First end 631 First end sealed portion 64 Second end 641 Second end sealed portion 65 Side end 67 Joined portion 671 Joined portion sealed portion 68 Non-sealed portion 70 Test piece

Claims (9)

A laminate comprising, in order from the outside to the inside, at least a substrate, an adhesive layer, a vapor deposition layer, and a sealant layer,
the substrate comprises a paper substrate layer;
The paper base layer has a basis weight of 20 g/m ² or more and 120 g/m ² or less,
the sealant layer includes a first resin layer in contact with the vapor-deposited layer, and a second resin layer located inside the first resin layer and containing polyolefin;
the vapor-deposited layer comprises a metal layer or an inorganic oxide layer;
the melting point of the first resin layer is higher than the melting point of the second resin layer;
the first resin layer contains a polyamide resin,
The thickness of the first resin layer is 1 μm or more and 6 μm or less . The laminate of claim 1, wherein the adhesive layer is an adhesive layer. The laminate described in claim 2, wherein the adhesive layer comprises a cured product of a composition containing a polyester polyol and an isocyanate compound. The laminate according to claim 1 , wherein the weight ratio of the paper substrate layer in the laminate is greater than 50%. The laminate according to claim 1 , wherein the second resin layer contains one or more polyolefins selected from the group consisting of polypropylene and polyethylene. The laminate according to claim 1 , wherein the vapor-deposited layer comprises an aluminum vapor-deposited layer. The laminate according to claim 1 , wherein the laminate has a tear strength of 1500 mN or more. 8. The laminate of claim 1 , wherein the laminate has a breaking energy of 520 J or greater. A packaging container comprising the laminate according to any one of claims 1 to 8 .