JP7510622B2 - Laminate, packaging material, packaging bag and stand-up pouch - Google Patents

Description

The present invention relates to a laminate, a packaging material, a packaging bag, and a stand-up pouch made from the laminate.

Traditionally, packaging materials have been made using resin films made from resin materials. For example, resin films made from polyethylene have moderate flexibility and transparency, as well as excellent heat sealability, and are therefore widely used as packaging materials.

Normally, resin films made of polyethylene cannot be used as a base material because they are inferior in terms of strength and heat resistance, and are instead used by laminating them with resin films made of polyester or polyamide, etc. For this reason, ordinary packaging materials are made of laminated films in which the base material and the heat seal layer are made of different types of resin materials (for example, Patent Document 1).

In recent years, with the growing demand for a recycling-oriented society, there is a demand for packaging materials with high recyclability. However, as mentioned above, conventional packaging materials are made up of different resin materials, and because it is difficult to separate the individual resin materials, they are not currently recycled.

JP 2009-202519 A

The inventors have discovered that polyethylene, which has conventionally been used as a heat seal layer, can be used as a substrate by forming it into a stretched film, and that by laminating the substrate with a heat seal layer made of polyethylene, it is possible to produce packaging materials that have sufficient strength and heat resistance and are also recyclable.

The present invention has been made in light of the above findings, and the problem to be solved by the present invention is to provide a laminate that can realize a packaging material that has sufficient strength and heat resistance to be applicable as a packaging material, and also has excellent recyclability.
Another problem to be solved by the present invention is to provide a packaging material formed from the laminate.
Another problem to be solved by the present invention is to provide a packaging bag made from the laminate.
A further object of the present invention is to provide a stand-up pouch made from the laminate.

The laminate of the present invention is a laminate including a substrate and a heat seal layer,
Both the substrate and the heat seal layer are made of polyethylene;
The substrate comprises a high density polyethylene layer, a medium density polyethylene layer, a low density polyethylene layer, a linear low density polyethylene layer or an ultra-low density polyethylene layer, and a medium density polyethylene layer;
It is characterized by being composed of a high-density polyethylene layer and a five-layer co-extruded stretched film.

In one embodiment of the present invention, the laminate comprises a vapor deposition film between the substrate and the heat seal layer.

In one embodiment of the present invention, the laminate includes an adhesive layer between the substrate and the deposited film,
the vapor-deposited film is an aluminum vapor-deposited film,
The adhesive layer is composed of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound.

In one embodiment of the present invention, the laminate further comprises an intermediate layer between the substrate and the heat seal layer, the intermediate layer being made of a stretched polyethylene film having a vapor deposition film on one side.

In one embodiment of the present invention, the laminate includes an adhesive layer between the substrate and the intermediate layer and between the intermediate layer and the heat seal layer.

In one embodiment of the present invention, the vapor-deposited film is an aluminum vapor-deposited film,
The adhesive layer adjacent to the vapor-deposited film is composed of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound.

In one embodiment of the present invention, the substrate is produced by the inflation method.

In one embodiment of the present invention, the polyethylene content in the entire laminate is 90% by mass or more.

In one embodiment of the present invention, the laminate is used for packaging material applications.

The packaging material of the present invention is characterized by being made using the above laminate.

The packaging bag of the present invention is produced using the laminate,
The thickness of the heat seal layer is 20 μm or more and 60 μm or less.

The stand-up pouch of the present invention is produced using the laminate,
The thickness of the heat seal layer is 50 μm or more and 200 μm or less.

The present invention provides a laminate that can be used as a packaging material that has the strength and heat resistance required for packaging and also has excellent recyclability.

1 is a schematic cross-sectional view showing one embodiment of a laminate of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present invention. FIG. 1 is a perspective view showing one embodiment of a packaging material produced using a laminate of the present invention. FIG. 1 is a perspective view showing one embodiment of a packaging material produced using a laminate of the present invention.

<Laminate>
The laminate according to the present invention will now be described with reference to the drawings.
As shown in FIG. 1, the laminate 10 includes a substrate 11 and a heat seal layer 12.
The substrate 11 comprises a high density polyethylene layer 13 , a medium density polyethylene layer 14 , a low density polyethylene layer, a linear low density polyethylene layer or an ultra low density polyethylene layer 15 , a medium density polyethylene layer 16 , and a high density polyethylene layer 17 .

In one embodiment of the present invention, as shown in FIG. 2, the laminate 10 can have a vapor deposition film 18 between the substrate 11 and the heat seal layer 12.

In one embodiment of the present invention, as shown in FIG. 3, the laminate 10 can include an adhesive layer 19 between the substrate 11 and the heat seal layer 12 or the vapor deposition film 18.

In one embodiment of the present invention, as shown in FIG. 4, the laminate 10 can include an intermediate layer 21 between the substrate 11 and the heat seal layer 12, the intermediate layer 21 including a vapor deposition film 18 and a stretched polyethylene film 20.

Furthermore, in one embodiment of the present invention, as shown in FIG. 5, the laminate 10 can have an adhesive layer 19 between the substrate 11 and the intermediate layer 21 and between the intermediate layer 21 and the heat seal layer 12.

In the laminate of the present invention, the polyethylene content is preferably 90% by mass or more.
By making the content of polyethylene in the entire laminate of the present invention 90% by mass or more, the recyclability of the laminate of the present invention can be improved.
The content of polyethylene in the laminate means the ratio of the content of polyethylene to the sum of the contents of the resin materials in each layer constituting the laminate.

The layers constituting the laminate of the present invention are described below.

<Substrate>
The substrate of the laminate of the present invention is made of polyethylene, and the heat seal layer described below is also made of polyethylene. By adopting such a configuration, the recyclability of the laminate can be improved.

The substrate is a stretched film made of polyethylene, which improves the heat resistance and strength of the laminate and also improves the printability of the substrate.
The stretched film may be a uniaxially stretched film or a biaxially stretched film.

The stretching ratio in the machine direction (MD) of the stretched film is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less.
By making the stretching ratio in the longitudinal direction (MD) of the stretched film 2 times or more, the strength and heat resistance of the laminate of the present invention can be improved. Furthermore, the printability of the substrate can be improved. In addition, since the transparency of the substrate can be improved, when an image is formed on the heat seal layer side surface of the substrate, the visibility of the image can be improved. On the other hand, the upper limit of the stretching ratio in the longitudinal direction (MD) of the stretched film is not particularly limited, but it is preferably 10 times or less from the viewpoint of the breaking limit of the stretched film.

The stretching ratio in the transverse direction (TD) of the stretched film is preferably 2 to 10 times, more preferably 3 to 7 times.
By making the stretching ratio of the stretched film in the transverse direction (TD) 2 times or more, the strength and heat resistance of the laminate of the present invention can be improved. Furthermore, the printability of the substrate can be improved. In addition, since the transparency of the substrate can be improved, when an image is formed on the heat seal layer side surface of the substrate, the visibility of the image can be improved. On the other hand, the upper limit of the stretching ratio in the transverse direction (TD) of the stretched film is not particularly limited, but it is preferably 10 times or less from the viewpoint of the breaking limit of the stretched film.

The haze value of the stretched film is preferably 30% or less, and more preferably 20% or less, which can improve the transparency of the stretched film.
In the present invention, the haze value of the stretched film is measured in accordance with JIS K 7105.

The substrate may have an image formed on its surface.
It is preferable that an image is formed on the surface on which a heat seal layer described below is provided, since this can prevent contact with the outside air and deterioration over time.
The image to be formed is not particularly limited, and may be a character, a pattern, a symbol, or a combination thereof.
The image formation on the substrate is preferably carried out using ink derived from biomass, whereby the laminate of the present invention can be used to produce packaging materials with less environmental impact.
The method for forming the image is not particularly limited, and examples of the method include conventionally known printing methods such as gravure printing, offset printing, flexographic printing, etc. Among these, flexographic printing is preferred from the viewpoint of environmental load.

The substrate provided in the laminate of the present invention has a configuration consisting of a five-layer co-extruded stretched film consisting of a high-density polyethylene layer, a medium-density polyethylene layer, a low-density polyethylene layer, a linear low-density polyethylene layer or an ultra-low-density polyethylene layer (hereinafter, for the sake of simplicity, in this paragraph, these will be referred to as the substrate intermediate layer), a medium-density polyethylene layer and a high-density polyethylene layer.
By adopting such a constitution, it is possible to improve the stretchability of the film, to improve the strength and heat resistance of the laminate of the present invention, and to prevent the occurrence of curling in the substrate.
Furthermore, the film production efficiency can be improved as described below.
In this case, the thickness of the high density polyethylene layer is preferably thinner than the thickness of the medium density polyethylene layer.
The ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer is preferably 1/10 or more and 1/1 or less, and more preferably 1/5 or more and 1/2 or less.
By setting the ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer to be 1/10 or more, the strength and heat resistance of the laminate of the present invention can be improved. Also, by setting the ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer to be 1/1 or less, the stretchability of the film can be improved.
In addition, the thickness of the high-density polyethylene layer is preferably the same as or greater than the thickness of the intermediate layer of the substrate.
The ratio of the thickness of the high-density polyethylene layer to the thickness of the intermediate substrate layer is preferably 1/0.25 or more and 1/2 or less, and more preferably 1/0.5 or more and 1/1 or less.
By setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the intermediate substrate layer to 1/0.25 or more, the heat resistance can be improved. Also, by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the intermediate substrate layer to 1/1 or less, the adhesion between the layers can be improved.
The thickness of each high density polyethylene layer is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 10 μm or less.
By making the thickness of the high-density polyethylene layer 1 μm or more, the strength and heat resistance of the laminate of the present invention can be further improved, and by making the thickness of the high-density polyethylene layer 20 μm or less, the processability of the laminate of the present invention can be further improved.
The thickness of each medium density polyethylene layer is preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less.
By making the thickness of the medium-density polyethylene layer 1 μm or more, the stretchability of the film can be further improved, and by making the thickness of the medium-density polyethylene layer 30 μm or less, the processability of the laminate of the present invention can be further improved.
The thickness of the substrate intermediate layer is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 5 μm or less.
By making the thickness of the intermediate layer of the substrate 1 μm or more, the adhesion between the high density polyethylene layer and the medium density polyethylene layer can be further improved, and by making the thickness of the intermediate layer of the substrate 10 μm or less, the processability of the laminate of the present invention can be further improved.

In one embodiment, a substrate having such a configuration can be produced by, for example, an inflation method.
Specifically, the film can be produced by co-extruding, from the outside, a high-density polyethylene layer, a medium-density polyethylene layer, and a low-density polyethylene layer, a linear low-density polyethylene layer, or an ultra-low-density polyethylene layer into a tubular shape, and then pressing the opposing low-density polyethylene layers, linear low-density polyethylene layers, or ultra-low-density polyethylene layers together using a rubber roll or the like.
By using such a method, the number of defective products during manufacturing can be significantly reduced, and ultimately, production efficiency can be improved.
In addition, the stretching can also be carried out in the inflation film forming machine, which can further improve the production efficiency.

In the present invention, the high-density polyethylene may be polyethylene having a density of 0.945 g/ ^cm3 or more, the medium-density polyethylene may be polyethylene having a density of 0.925 g/ ^cm3 or more and less than 0.945 g/ ^cm3 , the low-density polyethylene may be polyethylene having a density of 0.900 g/ ^cm3 or more and less than 0.925 g/ ^cm3 , the linear low-density polyethylene may be polyethylene having a density of 0.900 g/ ^cm3 or more and less than 0.925 g/ ^cm3 , and the very low-density polyethylene may be polyethylene having a density less than 0.900 g/ ^cm3 .

The polyethylenes with different densities and branches as described above can be obtained by appropriately selecting the polymerization method. For example, it is preferable to use a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as the polymerization catalyst, and to carry out the 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 single-site catalyst is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene transition metal compound or a nonmetallocene transition metal compound with an activating cocatalyst. Compared to multi-site catalysts, single-site catalysts have a uniform active site structure, and are therefore preferred because they can polymerize polymers with high molecular weights and highly uniform structures. As a single-site catalyst, it is particularly preferred to use a metallocene catalyst. A metallocene catalyst is a catalyst that contains each of the catalytic components of a transition metal compound of Group IV of the periodic table that contains a ligand having a cyclopentadienyl skeleton, a cocatalyst, and if necessary, an organometallic compound and a carrier.

In the above-mentioned transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group, or the like. The substituted cyclopentadienyl group has at least one substituent selected from a hydrocarbon group having 1 to 30 carbon atoms, a silyl group, a silyl-substituted alkyl group, a silyl-substituted aryl group, a cyano group, a cyanoalkyl group, a cyanoaryl group, a halogen group, a haloalkyl group, a halosilyl group, or the like. The substituted cyclopentadienyl group may have two or more substituents, and the substituents may be bonded to each other to form a ring, such as an indenyl ring, a fluorenyl ring, an azulenyl ring, or a hydrogenated product thereof. The rings formed by bonding the substituents to each other may further have substituents.

In the transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the transition metal may be zirconium, titanium, hafnium, etc., and zirconium and hafnium are particularly preferred. The transition metal compound usually has two ligands having a cyclopentadienyl skeleton, and it is preferred that the ligands having the cyclopentadienyl skeleton are bonded to each other by a bridging group. Examples of the bridging group include alkylene groups having 1 to 4 carbon atoms, silylene groups, substituted silylene groups such as dialkylsilylene groups and diarylsilylene groups, and substituted germylene groups such as dialkylgermylene groups and diarylgermylene groups. The substituted silylene group is preferred. The above transition metal compounds of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be used as a catalyst component, either alone or in a mixture of two or more types.

The co-catalyst refers to a catalyst that can effectively use the above-mentioned transition metal compound of Group IV of the periodic table as a polymerization catalyst, or can balance the ionic charge in a catalytically activated state. Examples of the co-catalyst include benzene-soluble aluminoxanes of organoaluminum oxy compounds and benzene-insoluble organoaluminum oxy compounds, ion-exchangeable layered silicates, boron compounds, ionic compounds consisting of cations with or without active hydrogen groups and non-coordinating anions, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing fluoro groups.

The transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be used by being supported on an inorganic or organic carrier. The carrier is preferably an inorganic or organic porous oxide, and specifically includes ion-exchange layered silicate such as montmorillonite, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, BaO, ThO ₂ , and mixtures thereof. Furthermore, examples of the organometallic compound that is used as necessary include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organoaluminum compounds are preferably used.

In addition, copolymers of ethylene and other monomers can also be used as long as they do not impair the characteristics of the present invention. Examples of ethylene copolymers include copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, and examples of α-olefins having 3 to 20 carbon atoms include 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. In addition, copolymers with vinyl acetate or acrylic esters can be used as long as they do not impair the object of the present invention.

In addition, in the present invention, biomass-derived ethylene may be used as a raw material for obtaining the above-mentioned polyethylene, instead of ethylene obtained from fossil fuels. Since such biomass-derived polyethylene is a carbon-neutral material, it can be used as a packaging material with even less environmental impact. Such biomass-derived polyethylene can be produced, for example, by a method such as that described in JP 2013-177531 A. In addition, commercially available biomass-derived polyethylene (for example, Green PE commercially available from Braskem) may also be used.

It is also possible to use polyethylene that has been recycled through mechanical recycling. Mechanical recycling generally refers to a method in which collected polyethylene film is crushed and washed with an alkali to remove dirt and foreign matter from the film surface, and then dried at high temperature and reduced pressure for a certain period of time to diffuse and decontaminate the contaminants remaining inside the film, removing dirt from the polyethylene film and returning it to polyethylene.

The substrate may contain additives within the range that does not impair the characteristics of the present invention, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

In addition, the substrate is preferably subjected to a surface treatment, which can improve adhesion to adjacent layers.
The method of the surface treatment is not particularly limited, and examples thereof 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, as well as chemical treatments such as oxidation treatment using chemicals.
Furthermore, an anchor coat layer may be formed on the surface of the substrate using a conventionally known anchor coat agent.

The thickness of the substrate is preferably 10 μm or more and 50 μm or less, and more preferably 12 μm or more and 30 μm or less.
By making the thickness of the substrate 10 μm or more, the strength of the laminate of the present invention can be improved, and by making the thickness of the substrate 50 μm or less, the processability of the laminate of the present invention can be improved.

The substrate can be produced by forming polyethylene into a film using the T-die method or inflation method, and then stretching the film.

When the substrate is produced by the T-die method, the MFR of the polyethylene constituting each layer is preferably 3 g/10 min or more and 20 g/10 min or less.
By setting the MFR of the polyethylene to 3 g/10 min or more, the processability of the laminate of the present invention can be improved, and by setting the MFR of the polyethylene to 20 g/10 min or less, the resin film can be prevented from breaking.

When the substrate is produced by an inflation method, the MFR of the polyethylene constituting each layer is preferably 0.5 g/10 min or more and 5 g/10 min or less.
By making the MFR of the polyethylene 0.5 g/10 min or more, the processability of the laminate of the present invention can be improved, and by making the MFR of the polyethylene 5 g/10 min or less, the film formability can be improved.

The substrate is not limited to those prepared by the above method, and commercially available substrates may also be used.

<Heat seal layer>
The heat seal layer of the laminate of the present invention is characterized by being made of polyethylene, like the above-mentioned base material. By using such a constitution, it is possible to obtain a packaging material that has sufficient strength and heat resistance as well as being recyclable.
However, the oriented polyethylene film is formed from an unoriented polyethylene resin film or by melt extrusion of polyethylene.

From the viewpoint of heat sealability, the polyethylene constituting the heat seal layer is preferably low density polyethylene (LDPE), linear low density polyethylene (LLDPE) or very high density polyethylene (VLDPE).
Copolymers of ethylene and other monomers can be used as long as they do not impair the characteristics of the present invention.
From the viewpoint of environmental load, biomass-derived polyethylene or recycled polyethylene is preferable.

The heat seal layer may contain the above additives as long as they do not impair the properties of the present invention.

In one embodiment, the heat seal layer has a multi-layer structure and includes, as an intermediate layer, a layer containing at least one of medium density polyethylene and high density polyethylene.
Specifically, the laminate may be configured as a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene/a layer containing at least one of medium-density polyethylene and high-density polyethylene/a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene.
By adopting such a configuration, the bag-making suitability and strength of the laminate of the present invention can be further improved while maintaining the heat sealability.

In another embodiment, the heat seal layer may be configured to include a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene/a layer containing biomass-derived polyethylene/a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene.
With such a structure, the environmental impact of packaging materials and the like produced using the laminate of the present invention can be further reduced.

It is preferable that the thickness of the heat seal layer is appropriately changed depending on the weight of the contents to be filled in the packaging material produced from the laminate of the present invention.
For example, when producing a packaging bag 20 as shown in FIG. 6 to be filled with a content of 1 g or more and 200 g or less, the thickness of the heat seal layer is preferably 20 μm or more and 60 μm or less.
By making the thickness of the heat seal layer 20 μm or more, it is possible to prevent the leakage of the filled contents due to the breakage of the heat seal layer, and by making the thickness of the heat seal layer 60 μm or less, it is possible to improve the processability of the laminate of the present invention.

Furthermore, for example, when producing a stand pouch 30 as shown in FIG. 7 to be filled with a content of 50 g or more and 2000 g or less, the thickness of the heat seal layer is preferably 50 μm or more and 200 μm or less.
By making the thickness of the heat seal layer 50 μm or more, it is possible to prevent the leakage of the filled contents due to the breakage of the heat seal layer, and by making the thickness of the heat seal layer 200 μm or less, it is possible to improve the processability of the laminate of the present invention.
The shaded areas in Figures 6 and 7 are heat-sealed areas.

<Vapor-deposited film>
The laminate of the present invention may include a vapor-deposited film between the substrate and the heat seal layer, which can improve the gas barrier properties, specifically the oxygen barrier properties and water vapor barrier properties, of the laminate.

Examples of vapor-deposited films include those composed of metals such as aluminum, and inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

The thickness of the evaporated film is preferably 1 nm or more and 150 nm or less, more preferably 5 nm or more and 60 nm or less, and even more preferably 10 nm or more and 40 nm or less.
By making the thickness of the vapor-deposited film 1 nm or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be further improved, and by making the thickness of the vapor-deposited film 150 nm or less, the occurrence of cracks in the vapor-deposited film can be prevented and the recyclability of the laminate of the present invention can be improved.

For the vapor-deposited film to be an aluminum vapor-deposited film, the OD value is preferably 2 or more and 3.5 or less. This makes it possible to improve the oxygen barrier property and water vapor barrier property while maintaining the productivity of the laminate of the present invention. In the present invention, the OD value can be measured in accordance with JIS-K-7361.

The vapor deposition film can be formed using a conventional method, for example, physical vapor deposition methods (PVD method) such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition methods (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

For example, a composite film consisting of two or more layers of vapor-deposited films of different inorganic oxides can be formed and used by combining physical vapor deposition and chemical vapor deposition. The degree of vacuum in the vapor deposition chamber is preferably about 10-2 to 10-8 mbar before oxygen is introduced, and about 10-1 to 10-6 mbar after oxygen is introduced. The amount of oxygen introduced varies depending on the size of the vapor deposition machine. For the oxygen to be introduced, an inert gas such as argon gas, helium gas, or nitrogen gas may be used as a carrier gas to the extent that no problems occur. The film transport speed can be about 10 to 800 m/min.

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

<Adhesive Layer>
In one embodiment, the laminate of the present invention may include an adhesive layer between any two of the layers, thereby improving the adhesion between the layers.

The adhesive layer includes at least one adhesive, and may be a one-component curing type, a two-component curing type, or a non-curing type adhesive. The adhesive may be a solvent-free adhesive or a solvent-based adhesive, but from the viewpoint of environmental load, a solvent-free adhesive is preferably used.
Examples of solvent-free adhesives include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Among these, two-component curing urethane adhesives can be preferably used.
Examples of the solvent-based adhesive include rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives.

In addition, when an adhesive layer is provided adjacent to the vapor deposition film which is an aluminum vapor deposition film, the adhesive layer is preferably composed of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound.
By configuring the adhesive layer in this way, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be further improved.
Furthermore, when a laminate having a vapor-deposited film is applied to a packaging material, a bending load is applied to the laminate by a molding machine, etc., which may cause cracks in the aluminum vapor-deposited film. By using the specific adhesive as described above, it is possible to suppress a decrease in the oxygen barrier property and water vapor barrier property even if cracks occur in the aluminum vapor-deposited film.

The polyester polyol has two or more hydroxyl groups as functional groups in one molecule, and the isocyanate compound has two or more isocyanate groups as functional groups in one molecule.
The polyester polyol has, for example, a polyester structure or a polyester polyurethane structure as a main skeleton.

Specific examples of resin compositions containing polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound include the PASLIM series sold by DIC Corporation.

The resin composition may further contain a plate-like inorganic compound, a coupling agent, cyclodextrin and/or its derivatives, etc.

As the polyester polyol having two or more hydroxyl groups in one molecule as a functional group, for example, the following [First Example] to [Third Example] can be used.
[Example 1] Polyester polyol obtained by polycondensation of an ortho-oriented polycarboxylic acid or its anhydride with a polyhydric alcohol. [Example 2] Polyester polyol having a glycerol skeleton. [Example 3] Polyester polyol having an isocyanuric ring. Each polyester polyol will be explained below.

The polyester polyol according to the first example is a polycondensate obtained by polycondensing a polycarboxylic acid component containing at least one or more types of orthophthalic acid and its anhydride, and a polyhydric alcohol component containing at least one type selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol.
In particular, polyester polyols in which the content of orthophthalic acid or its anhydride relative to the total amount of polyvalent carboxylic acids 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, but may be copolymerized with other polycarboxylic acid components as long as the effect of the present embodiment is not impaired.
Specifically, aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecane dicarboxylic acid, unsaturated bond-containing polycarboxylic acids such as maleic anhydride, maleic acid, and fumaric acid, alicyclic polycarboxylic acids such as 1,3-cyclopentane dicarboxylic acid and 1,4-cyclohexane dicarboxylic 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, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, anhydrides of these dicarboxylic acids, and ester-forming derivatives of these dicarboxylic acids, polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids, etc. are exemplified. Among these, succinic acid, 1,3-cyclopentane dicarboxylic acid, and isophthalic acid are preferred.
Two or more of the above other polyvalent carboxylic acids may be used.

As a polyester polyol according to the second example, a polyester polyol having a glycerol skeleton represented by the general formula (1) can be mentioned.
In general formula (1), R1, R2, and R3 each independently represent 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 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, and Y represents an alkylene group having 2 to 6 carbon atoms.
However, at least one of R1, R2, and R3 represents a group represented by general formula (2).

In general formula (1), at least one of R1, R2, and R3 must be a group represented by general formula (2). In particular, it is preferable that all of R1, R2, and R3 are groups represented by general formula (2).

The compound may be a mixture of two or more of the following: a compound in which any one of R1, R2, and R3 is a group represented by general formula (2); a compound in which any two of R1, R2, and R3 are groups represented by general formula (2); and a compound in which all of R1, R2, and R3 are groups represented by general formula (2).

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, and the substituent is bonded to any carbon atom on X that is different from the free radical. The substituents 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, a 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 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. Of these, a propylene group or an ethylene group is preferable, and an ethylene group is most preferable.

The polyester resin compound having a glycerol skeleton represented by general formula (1) can be synthesized by reacting glycerol, 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-anthracene carboxylic acid or anhydride.
These compounds may have a substituent at 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 may be an alkylene diol having 2 to 6 carbon atoms. Examples of such diols 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 the general formula (3), R1, R2, and R3 each independently represent "-(CH2)n1-OH (wherein n1 represents an integer of 2 to 4)" or a structure represented by the general formula (4).

In the general formula (4), n2 represents an integer of 2 to 4, n3 represents an integer of 1 to 5, X represents an arylene group selected from the group consisting of 1,2-phenylene group, 1,2-naphthylene group, 2,3-naphthylene group, 2,3-anthraquinonediyl group, and 2,3-anthracenediyl group, which may have a substituent, and Y represents an alkylene group having 2 to 6 carbon atoms. However, at least one of R1, R2, and R3 is a group represented by the general formula (4).

In general formula (3), the alkylene group represented by -(CH2)n1- may be linear or branched. n1 is preferably 2 or 3, and most preferably 2.

In formula (4), n2 represents an integer of 2 to 4, and n3 represents an integer of 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, and the substituent is bonded to any carbon atom on X that is different from the free radical. The substituents 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, a 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. Of these, a propylene group or an ethylene group is preferable, and an ethylene group is most preferable.

In general formula (3), at least one of R1, R2, and R3 is a group represented by general formula (4). Of these, it is preferable that all of R1, R2, and R3 are groups represented by general formula (4).

The compound may be a mixture of two or more of the following: a compound in which any one of R1, R2, and R3 is a group represented by general formula (4); a compound in which any two of R1, R2, and R3 are groups represented by general formula (4); and a compound in which all of R1, R2, and R3 are groups represented by general formula (4).

The polyester polyol having an isocyanuric ring represented by the general formula (3) can be 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.

Examples of triols having an isocyanuric ring include 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.

Examples of aromatic polycarboxylic acids or anhydrides in which the 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-anthracene carboxylic acid or anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring.

Such substituents include 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 may be 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 adhesive properties and are therefore preferred.

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

The isocyanate compound has two or more isocyanate groups in the molecule.
The isocyanate compound may be either aromatic or aliphatic, and may be either a low molecular weight compound or a high molecular weight compound.
Furthermore, the isocyanate compound may be a blocked isocyanate compound obtained by subjecting a known isocyanate blocking agent to an addition reaction 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.

Specific 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 their alkylene oxide adducts, 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, and metaxylylenediamine. Examples of molecular weight active hydrogen compounds include polymeric active hydrogen compounds such as various polyester resins, polyether polyols, and polyamides.

The phosphoric acid-modified compound is, for example, a compound represented by the following general formula (5) or (6).
In general formula (5), R1, R2, and R3 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 which is a hydrogen atom, and n is an integer of 1 to 4.
In the formula, 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 which has a (meth)acryloyloxy group; n is an integer of 1 to 4, x is an integer of 0 to 30, and y is an integer of 0 to 30, except for the case where both x and y are 0.

More specifically, examples of such acids 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, and one or more of these can be used.

The content of the phosphoric acid-modified compound in the resin composition is preferably from 0.005% by mass to 10% by mass, and more preferably from 0.01% by mass to 1% by mass.
By adjusting the content of the phosphoric acid-modified compound to 0.005% by mass or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be improved, and by adjusting the content of the phosphoric acid-modified compound to 10% by mass or less, the adhesiveness of the adhesive layer can be improved.

The resin composition containing the polyester polyol, the isocyanate compound and the phosphoric acid-modified compound may contain a plate-like inorganic compound, which can improve the adhesiveness of the adhesive layer and the bending load resistance of the laminate of the present invention.
Examples of the plate-like inorganic compounds include kaolinite-serpentine group clay minerals (such as halloysite, kaolinite, endelite, dickite, nacrite, antigorite, and chrysotile) and pyrophyllite-talc group (such as pyrophyllite, talc, and keroli).

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

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(a Examples of such silanes include N-(aminoethyl) gamma-aminopropyl methyldimethoxysilane, N-β(aminoethyl) gamma-aminopropyl trimethoxysilane, N-β(aminoethyl) gamma-aminopropyl triethoxysilane, gamma-aminopropyl trimethoxysilane, gamma-aminopropyl triethoxysilane, N-phenyl-gamma-aminopropyl trimethoxysilane, gamma-chloropropyl trimethoxysilane, gamma-mercaptopropyl trimethoxysilane, 3-isocyanatopropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, and 3-triethoxysilyl-N-(1,3-dimethyl-butylidene).

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)oxy Examples include bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, diisostearoyl ethylene titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and dicumyl phenyloxyacetate titanate.

Specific examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate, diisopropoxyaluminum ethyl acetoacetate, diisopropoxyaluminum monomethacrylate, isopropoxyaluminum alkyl acetoacetate mono(dioctyl phosphate), aluminum 2-ethylhexanoate oxide trimer, aluminum stearate oxide trimer, and alkyl acetoacetate aluminum oxide trimer.

The resin composition may contain cyclodextrin and/or a derivative thereof, which can improve the adhesiveness of the adhesive layer and the bending load resistance of the laminate of the present invention.
Specifically, for example, cyclodextrin, alkylated cyclodextrin, acetylated cyclodextrin, hydroxyalkylated cyclodextrin, and other cyclodextrins in which the hydrogen atoms of the hydroxyl groups of the glucose units of cyclodextrin are substituted with other functional groups can be used. Branched cyclic dextrins can also be used.
Furthermore, 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. Hereinafter, these cyclodextrins and/or their derivatives may be collectively referred to as dextrin compounds.

From the viewpoint of compatibility and dispersibility in the resin composition, it is preferable to use a cyclodextrin derivative as the cyclodextrin compound.

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.

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

Examples of hydroxyalkylated cyclodextrins include 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 preferably 0.5 μm or more and 6 μm or less, more preferably 0.8 μm or more and 5 μm or less, and even more preferably 1 μm or more and 4.5 μm or less.
By making the thickness of the adhesive layer 0.5 μm or more, the adhesiveness of the adhesive layer can be improved. In addition, when an adhesive layer made of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound is provided adjacent to an aluminum vapor deposition film, the bending load resistance of the laminate can be improved.
By setting the thickness of the adhesive layer to 6 μm or less, the processability of the laminate can be improved.

The adhesive layer can be formed by applying and drying onto a substrate or the like using a conventional method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, or transfer roll coating.

<Middle class>
In one embodiment, the laminate of the present invention may include an intermediate layer between the substrate and the heat seal layer, the intermediate layer being made of a stretched polyethylene film having a deposition film on one side thereof, thereby making it possible to further improve the strength, oxygen barrier property, and water vapor barrier property of the laminate.

(Vapor-deposited film)
The intermediate layer includes a vapor-deposited film, which can improve the gas barrier properties, particularly the oxygen barrier properties and water vapor barrier properties.

Examples of vapor-deposited films include those composed of metals such as aluminum, and inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

The thickness of the evaporated film is preferably 1 nm or more and 150 nm or less, more preferably 5 nm or more and 60 nm or less, and even more preferably 10 nm or more and 40 nm or less.
By making the thickness of the vapor-deposited film 1 nm or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be further improved, and by making the thickness of the vapor-deposited film 150 nm or less, the occurrence of cracks in the vapor-deposited film can be prevented and the recyclability of the laminate of the present invention can be improved.

For the vapor-deposited film to be an aluminum vapor-deposited film, the OD value is preferably 2 or more and 3.5 or less. This makes it possible to improve the oxygen barrier property and water vapor barrier property while maintaining the productivity of the laminate of the present invention. In the present invention, the OD value can be measured in accordance with JIS-K-7361.

The deposition film can be formed by the above method.

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

(Stretched polyethylene film)
The stretched polyethylene film constituting the intermediate layer is characterized by being made of polyethylene like the above-mentioned base material and heat seal layer. By adopting such a configuration, it is possible to obtain a recyclable packaging material while maintaining the strength and heat resistance as a packaging material.

Stretched polyethylene films are made of polyethylene and are used to improve the strength and heat resistance of packaging materials. Stretched films may be uniaxially or biaxially stretched films.

The stretching ratio in the machine direction (MD) of the stretched film is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less.
By setting the stretching ratio in the machine direction (MD) of the stretched film to 2 times or more, the strength and heat resistance of the laminate of the present invention can be improved. On the other hand, the upper limit of the stretching ratio in the machine direction (MD) of the stretched film is not particularly limited, but is preferably set to 10 times or less from the viewpoint of the breaking limit of the stretched film.

The stretching ratio in the transverse direction (TD) of the stretched film is preferably 2 to 10 times, more preferably 3 to 7 times.
By setting the stretching ratio in the transverse direction (TD) of the stretched film to 2 times or more, the strength and heat resistance of the laminate of the present invention can be improved. On the other hand, the upper limit of the stretching ratio in the transverse direction (TD) of the stretched film is not particularly limited, but is preferably set to 10 times or less from the viewpoint of the breaking limit of the stretched film.

As the polyethylene contained in the stretched polyethylene film, among the above, high density polyethylene and medium density polyethylene are preferred from the viewpoints of strength, heat resistance, and suitability for stretching the film, and medium density polyethylene is more preferred from the viewpoint of suitability for stretching.
The intermediate layer may have the above-mentioned multi-layer structure, similar to the substrate.

The stretched polyethylene film may contain the above additives to the extent that the properties of the present invention are not impaired.

The thickness of the stretched polyethylene film is preferably 9 μm or more and 50 μm or less, and more preferably 12 μm or more and 30 μm or less.
By making the thickness of the stretched polyethylene film 9 μm or more, the strength and heat resistance of the laminate of the present invention can be further improved, and by making the thickness of the stretched polyethylene film 50 μm or less, the processability of the laminate of the present invention can be improved.

The stretched polyethylene film may be produced by the T-die method or inflation method, or a commercially available film may be used.

<Applications>
The laminate of the present invention can be particularly suitably used for packaging material applications.
The packaging material is not particularly limited, and may be a packaging bag 30 as shown in Fig. 6, or a stand pouch 40 having a body 41 and a bottom 42 as shown in Fig. 7. In the stand pouch, only the body may be formed of the laminate, only the bottom may be formed of the laminate, or both the body and the bottom may be formed of the laminate.

The packaging bag can be produced by folding the laminate in half, overlapping the laminate so that the heat seal layer is on the inside, and heat sealing the ends.
Alternatively, the packaging bag can be produced by overlapping two laminates with their heat seal layers facing each other and heat sealing the ends thereof.

A stand pouch can be manufactured by heat sealing the laminate into a cylindrical shape with the heat seal layer on the inside to form a body, then folding the laminate into a V shape with the heat seal layer on the inside, sandwiching one end of the body, and heat sealing to form a bottom.

The heat sealing method is not particularly limited, and can be performed by known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, etc.

The contents filled in the packaging material are not particularly limited, and may be liquid, powder, or gel. In addition, the contents may be food or non-food.
After filling the container with the contents, the opening can be heat sealed to form a package.

The present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples.

<Example 1-1>
High density polyethylene (density: 0.960 g/cm ³ , melting point: 130° C., MFR: 0.85 g/10 min, manufactured by Dowchemical, trade name: Elite 5960), medium density polyethylene (density: 0.940 g/cm ³ , melting point: 126° C., MFR: 0.85 g/10 min, manufactured by Dowchemical, trade name: Elite 5940), and very low density polyethylene (density: 0.870 g/cm ³ , melting point: 55° C., MFR: 1.0 g/10 min, manufactured by Dowchemical, trade name: Affinity EG8100G) was extruded by inflation molding into a tubular film having a high density polyethylene layer (12.5 μm), a medium density polyethylene layer (43.75 μm), and an ultra-low density polyethylene layer (6.25 μm) from the outside, and then the inner ultra-low density polyethylene layers were pressed together using a rubber roll to obtain a 125 μm-thick polyethylene film having a high density polyethylene layer (12.5 μm), a medium density polyethylene layer (43.75 μm), an ultra-low density polyethylene layer (12.5 μm), a medium density polyethylene layer (43.75 μm), and a high density polyethylene layer (12.5 μm).
This polyethylene film was stretched in the longitudinal direction (MD) at a stretching ratio of 5 times to obtain a substrate A having a thickness of 25 μm.
The haze value of the substrate A was measured in accordance with JIS K 7105 and was found to be 6.2%.

An image was formed on one side of substrate A by gravure printing using oil-based gravure ink (manufactured by DIC Graphics Corporation, product name: Finart).

A mixture (2:8 (by mass)) of linear low-density polyethylene A (density: 0.923 g/cm ³ , melting point: 121° C., MFR: 1.5 g/10 min, Prime Polymer, product name: SP2510), linear low-density polyethylene A and biomass-derived polyethylene (density: 0.916 g/cm ³ , MFR: 1.3 g/10 min, biomass ratio: 87%, Braskem, product name: SLL118), and linear low-density polyethylene B (density: 0.913 g/cm ³ , MFR: 1.5 g/10 min, Prime Polymer, product name: SP2510) were mixed. , melting point 116°C, MFR: 2.0 g/10 min, manufactured by Prime Polymer, product name: SP1520) was formed into a film by an inflation molding method to prepare a 50 μm-thick heat seal layer A including a 17 μm-thick layer made of linear low-density polyethylene A, a 16 μm-thick layer made of linear low-density polyethylene A and biomass-derived polyethylene, and a 17 μm-thick layer made of linear low-density polyethylene B.

The image forming surface of the substrate A and the layer of linear low-density polyethylene A of the heat seal layer A were laminated via a two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-77T/H-7) to obtain a laminate of the present invention.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 95% by mass.

<Comparative Example 1-1>
The high density polyethylene, the medium density polyethylene and the very low density polyethylene were extruded from the outside by an inflation molding method into a tubular film having a high density polyethylene layer, a medium density polyethylene layer and a very low density polyethylene layer, and then the inner very low density polyethylene layers were pressed together by a rubber roll to obtain a substrate a having a thickness of 25 μm and having a high density polyethylene layer (2.5 μm), a medium density polyethylene layer (8.75 μm), a very low density polyethylene layer (2.5 μm), a medium density polyethylene layer (8.75 μm) and a high density polyethylene layer (2.5 μm).
The haze value of the substrate a was measured in accordance with JIS K 7105 and was found to be 21.3%.

An image was formed on one side of substrate a by gravure printing using the above oil-based gravure ink.

The image forming surface of the substrate a and the layer made of the linear low-density polyethylene A of the heat seal layer A were laminated via the two-component curing urethane adhesive to obtain a laminate.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 95% by mass.

<Comparative Example 1-2>
A laminate was produced in the same manner as in Example 1-1, except that the substrate A was changed to a biaxially stretched PET film having a thickness of 12 μm (manufactured by Toyobo Co., Ltd., product name: E5100).
The proportion of polyethylene in the thus obtained laminate was 75% by mass.

<Example 2-1>
The above-mentioned base material A was prepared.

An image was formed on one side of substrate A by gravure printing using oil-based gravure ink (manufactured by DIC Graphics Corporation, product name: Finart).

The linear low-density polyethylene A, a mixture of the linear low-density polyethylene A and the biomass-derived polyethylene (2:8 (by mass)), and the linear low-density polyethylene B were formed into a film by inflation molding to produce a 100 μm-thick heat seal layer B having a 34 μm-thick layer of linear low-density polyethylene A, a 32 μm-thick layer of linear low-density polyethylene A and biomass-derived polyethylene, and a 34 μm-thick layer of linear low-density polyethylene B.

The image forming surface of the substrate A and the layer of linear low density polyethylene A of the heat seal layer B were laminated via the two-component curing urethane adhesive to obtain a laminate of the present invention.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 97% by mass.

<Comparative Example 2-1>
The above-mentioned substrate a was prepared.

An image was formed on one side of substrate a by gravure printing using the above oil-based gravure ink.

The image forming surface of the substrate a and the layer made of linear low-density polyethylene A of the heat seal layer B were laminated via the two-component curing urethane adhesive to obtain a laminate.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 97% by mass.

<Comparative Example 2-2>
A laminate was produced in the same manner as in Example 2-1, except that the substrate A was changed to the above-mentioned biaxially stretched PET film having a thickness of 12 μm.
The proportion of polyethylene in the thus obtained laminate was 86% by mass.

<Example 3-1>
The above-mentioned base material A was prepared.

An image was formed on one side of substrate A by gravure printing using oil-based gravure ink (manufactured by DIC Graphics Corporation, product name: Finart).

A heat seal layer A was prepared, and a 20 nm thick aluminum vapor deposition film was formed on this linear low density polyethylene A by the PVD method.

The image forming surface of the substrate A and the vapor deposition surface of the heat seal layer A were laminated together via the above-mentioned two-component curing urethane adhesive to obtain a laminate of the present invention.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 95% by mass.

<Example 3-2>
A laminate of the present invention was produced in the same manner as in Example 3-1, except that in Example 3-1, the image forming surface of the substrate A and the vapor deposition surface of the heat seal layer A were bonded with a two-liquid curing adhesive containing an isocyanate compound and a phosphoric acid-modified compound (manufactured by DIC Corporation, PASLIM VM001/VM102CP).

<Comparative Example 3-1>
The above-mentioned substrate a was prepared.

An image was formed on one side of substrate a by gravure printing using the above oil-based gravure ink.

A heat seal layer A was prepared, and a 20 nm thick aluminum vapor deposition film was formed on this linear low density polyethylene A by the PVD method.

The image-forming surface of the substrate a and the vapor-deposited surface of the heat seal layer A were laminated together via the two-component curing urethane adhesive to obtain a laminate.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 95% by mass.

<Comparative Example 3-2>
A laminate was produced in the same manner as in Example 3-1, except that the substrate A was changed to the above-mentioned biaxially stretched PET film having a thickness of 12 μm.
The proportion of polyethylene in the thus obtained laminate was 76% by mass.

<Example 4-1>
The above-mentioned base material A was prepared.

An image was formed on one side of substrate A by gravure printing using oil-based gravure ink (manufactured by DIC Graphics Corporation, product name: Finart).

The medium density polyethylene was formed into a film by inflation molding to obtain a polyethylene film having a thickness of 100 μm, which was then stretched in the longitudinal direction (MD) at a stretching ratio of 5 to obtain a stretched polyethylene film A having a thickness of 20 μm. Next, a 20 nm thick aluminum vapor deposition film was formed on one side of the stretched polyethylene film A by the PVD method to obtain an intermediate layer A.

The image forming surface of the substrate A was laminated onto the vapor deposition surface of the intermediate layer A via the above-mentioned two-component curing urethane adhesive. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm.

A heat seal layer A was prepared. Next, a layer made of linear low density polyethylene A of the heat seal layer A was laminated onto the non-vapor-deposited surface of the intermediate layer A via the above-mentioned two-component curing urethane-based adhesive to obtain a laminate of the present invention.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 93% by mass.

<Example 4-2>
A laminate of the present invention was produced in the same manner as in Example 4-1, except that the image-forming surface of the substrate A and the vapor-deposited surface of the intermediate layer A were bonded to each other using a two-component curing adhesive containing an isocyanate compound and a phosphoric acid-modified compound (manufactured by DIC Corporation, PASLIM VM001/VM102CP).

<Comparative Example 4-1>
The above-mentioned substrate a was prepared.

An image was formed on one side of substrate a by gravure printing using oil-based gravure ink (manufactured by DIC Graphics Corporation, product name: Finart).

The medium density polyethylene was formed into a film by inflation molding to obtain a stretched polyethylene film a having a thickness of 20 μm. Next, an aluminum vapor deposition film having a thickness of 20 nm was formed on one side of the stretched polyethylene film a by PVD to obtain an intermediate layer a.

The image forming surface of the substrate a was laminated onto the vapor deposition surface of the intermediate layer a via the above-mentioned two-component curing urethane adhesive. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm.

A heat seal layer A was prepared, and this layer made of linear low density polyethylene A was laminated onto the non-vapor-deposited surface of the intermediate layer a via the above-mentioned two-component curing urethane adhesive to obtain a laminate.
The adhesive layer formed from the two-component curing urethane adhesive had a thickness of 3.0 μm.
The proportion of polyethylene in the thus obtained laminate was 93% by mass.

<Comparative Example 4-2>
A laminate was obtained in the same manner as in Example 4-1, except that the stretched polyethylene films of the substrate A and the intermediate layer A were changed to biaxially stretched polyester films having a thickness of 12 μm (product name: E5100, manufactured by Toyobo Co., Ltd.). The proportion of polyethylene in the thus obtained laminate was 62% by mass.

<Recyclability evaluation>
The recyclability of the laminates obtained in the above Examples and Comparative Examples was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: The polyethylene content in the laminate was 90% by mass or more.
x: The polyethylene content in the laminate was less than 90% by mass.

<Heat resistance evaluation>
Two test pieces measuring 80 mm in length and 80 mm in width were prepared from each of the laminates obtained in Example 1-1 and Comparative Examples 1-1 to 1-2, Examples 3-1 to 3-2 and Comparative Examples 3-1 to 3-2, and Examples 4-1 to 4-2 and Comparative Examples 4-1 to 4-2.
Two test pieces were overlapped with the heat seal layers facing each other, and three sides were heat sealed at 140° C. to prepare a packaging bag.
Two test pieces each having a length of 110 mm and a width of 150 mm were prepared from the laminates obtained in Example 2-1 and Comparative Examples 2-1 and 2-2.
Two test pieces were overlapped with the heat seal layers facing each other, and two sides were heat sealed at 140° C. to form a cylindrical body.
Next, one test piece measuring 110 mm in length and 150 mm in width was prepared from the laminate obtained in Example 2-1 and Comparative Examples 2-1 to 2-2 above, folded in a V shape so that the heat-sealed layer was on the outside, and heat-sealed to the cylindrical body at 140°C to form a bottom and produce a stand-up pouch.
The produced packaging materials were visually observed and evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 to 4.
(Evaluation criteria)
◯: No wrinkles or the like were observed on the surface of the packaging material, and no adhesion to the heat seal bar was observed.
×: Wrinkles or the like were generated on the surface of the packaging material, and adhesion to the heat seal bar was observed, and bags could not be made.

<Printability evaluation>
The images formed on the substrates of the laminates produced in the above Examples and Comparative Examples were visually observed and evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 to 4.
(Evaluation criteria)
A: The dimensional stability during printing was good, and a good image was formed without rubbing, bleeding, or the like.
×: The film expanded and contracted during printing, causing rubbing and bleeding in the formed image.

<Rigidity evaluation>
The laminates prepared in the above Examples and Comparative Examples were cut into test pieces with a width of 10 mm, and their stiffness was measured using a loop stiffness measuring tester (manufactured by Toyo Seiki Seisakusho, product name: Loop Stiffness Tester). The length of the loop was 60 mm. The measurement results are summarized in Tables 1 to 4.

<Strength test>
The laminates produced in the above Examples and Comparative Examples were measured for strength when pierced with a needle having a diameter of 0.5 mm using a tensile tester (manufactured by Orientec Co., Ltd., product name: RTC-1310A). The piercing speed was 50 mm/min. The measurement results are summarized in Tables 1 to 4.

<Flexural load resistance test>
First, the oxygen permeability and water vapor permeability of the laminates obtained in the above Examples 3-1 to 3-2, Comparative Examples 3-1 to 3-2, Examples 4-1 to 4-2, and Comparative Examples 4-1 to 4-2 were measured.
The oxygen permeability was measured using OXTRAN2/20 manufactured by MOCON under conditions of 23° C. and 90% RH, and the water vapor permeability was measured using PERMATRAN3/31 manufactured by MOCON under conditions of 40° C. and 90% RH.
Furthermore, the laminates obtained in the above Examples 3-1 to 3-2 and Comparative Examples 3-1 to 3-2, as well as Examples 4-1 to 4-2 and Comparative Examples 4-1 to 4-2, were subjected to a bending load (stroke: 155 mm, bending motion: 440°) five times in accordance with ASTM F 392 using a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd., product name: BE1006BE).
After the bending load, the oxygen permeability and water vapor permeability of the laminate were measured.
The oxygen permeability and water vapor permeability of the laminate before and after the flex load test are shown in Tables 3 and 4.

10: Laminate, 11: Base material, 12: Heat seal layer, 13: High density polyethylene layer, 14: Medium density polyethylene layer, 15: Low density polyethylene layer, linear low density polyethylene layer or ultra-low density polyethylene layer, 16: Medium density polyethylene layer, 17: High density polyethylene layer, 18: Vapor deposition film, 19: Adhesive layer, 20: Stretched polyethylene film, 21: Intermediate layer, 30: Packaging bag, 40: Stand pouch, 41: Body, 42: Bottom

Claims (10)

A laminate comprising a substrate and a heat seal layer,
Both the substrate and the heat seal layer are made of polyethylene, and the polyethylene content in the entire laminate is 90% by mass or more;
A printing process is performed on the surface of the base material,
The substrate is a co-extruded stretched film,
The co-extrusion stretched film is
a layer comprising high density polyethylene;
a layer comprising medium density polyethylene;
a layer containing low density polyethylene, a layer containing linear low density polyethylene, or a layer containing very low density polyethylene;
a layer comprising medium density polyethylene;
a layer comprising high density polyethylene;
Equipped with
A laminate comprising a vapor-deposited film between the substrate and the heat seal layer . An adhesive layer is provided between the substrate and the vapor-deposited film,
the vapor-deposited film is an aluminum vapor-deposited film,
The laminate according to claim 1 , wherein the adhesive layer is formed of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound. An intermediate layer is further provided between the substrate and the heat seal layer,
3. The laminate according to claim 1 , wherein the intermediate layer is a stretched polyethylene film having a vapor-deposited film on one side thereof. The laminate of claim 3 , further comprising an adhesive layer between the substrate and the intermediate layer and between the intermediate layer and the heat seal layer. the vapor-deposited film is an aluminum vapor-deposited film,
The laminate according to claim 4 , wherein the adhesive layer adjacent to the vapor-deposited film is composed of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound. The laminate according to any one of claims 1 to 4 , wherein the substrate is produced by an inflation method. The laminate according to any one of claims 1 to 6 , which is used for packaging material applications. A packaging material produced using the laminate according to any one of claims 1 to 7 . A packaging bag,
A laminate according to any one of claims 1 to 7 ,
A packaging bag, characterized in that the heat seal layer has a thickness of 20 μm or more and 60 μm or less. It is a stand-up pouch,
A laminate according to any one of claims 1 to 7 ,
A stand pouch, characterized in that the heat seal layer has a thickness of 50 μm or more and 200 μm or less.