Laminates, packaging materials, packaging bags and stand-up pouches

Abstract

To provide a laminate that can achieve a packaging material having sufficient strength and heat resistance as the packaging material and also having excellent recyclability.SOLUTION: A laminate has a base material and a heat seal layer. Each of the base material and the heat seal layer is composed of polyethylene. The base material comprises a five-layer co-extruded stretched film of: high-density polyethylene layer; middle-density polyethylene layer; low-density polyethylene layer, linear low-density polyethylene layer or ultra low-density polyethylene layer; middle-density polyethylene layer; and high-density polyethylene layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laminate, a packaging material composed of the laminate, a packaging bag, and a stand-up pouch.

Background Art

[0002] Conventionally, packaging materials and the like are produced using a resin film made of a resin material. For example, a resin film made of polyethylene has appropriate flexibility and transparency. At the same time, since it has excellent heat-sealability, it is widely used for packaging materials.

[0003] Generally, a resin film made of polyethylene is inferior in terms of strength and heat resistance, so it cannot be used as a base material and is used by laminating it with a resin film made of polyester, polyamide, or the like. Therefore, ordinary packaging materials and the like are composed of a laminated film in which the base material and the heat-seal layer are made of different resin materials (for example, Patent Document 1).

[0004] In recent years, with the increasing demand for building a recycling-oriented society, packaging materials with high recyclability are required. However, conventional packages are composed of different resin materials as described above, and it is difficult to separate them by resin material, so they are not recycled at present.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The inventors have found that polyethylene, which was conventionally used as a heat-seal layer, can be used as a base material by making it into a stretched film, and that by laminating this base material 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.

[0007] This invention has been made in view of the above findings, and the problem it aims to solve 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 is also excellent in terms of recyclability. Furthermore, the problem that the present invention aims to solve is to provide a packaging material composed of the laminate. Furthermore, the problem that the present invention aims to solve is to provide a packaging bag made from the laminate. Furthermore, the problem that the present invention aims to solve is to provide a stand pouch made from the laminate. [Means for solving the problem]

[0008] The laminate of the present invention is a laminate comprising a substrate and a heat-seal layer, Both the base material and the heat-seal layer are made of polyethylene. The base material consists 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, and a medium-density polyethylene layer. It is characterized by comprising a high-density polyethylene layer and a five-layer co-pressed stretched film.

[0009] In one embodiment of the present invention, the laminate comprises a vapor-deposited film between the substrate and the heat-seal layer.

[0010] In one embodiment of the present invention, the laminate comprises an adhesive layer between the substrate and the vapor-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 phosphate-modified compound.

[0011] In one embodiment of the present invention, the laminate further comprises an intermediate layer between the substrate and the heat-seal layer, and the intermediate layer is made of a stretched polyethylene film having a vapor-deposited film on one side.

[0012] In one embodiment of the present invention, the laminate includes adhesive layers between the substrate and the intermediate layer, and between the intermediate layer and the heat seal layer.

[0013] In one embodiment of the present invention, the vapor-deposited film is an aluminum vapor-deposited film. The vapor-deposited film and the adjacent adhesive layer are composed of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphate-modified compound.

[0014] In one embodiment of the present invention, the substrate is manufactured by the inflation method.

[0015] In one embodiment of the present invention, the polyethylene content in the entire laminate is 90% by mass or more.

[0016] In one embodiment of the present invention, the laminate is used for packaging material applications.

[0017] The packaging material of the present invention is characterized by being manufactured using the above-mentioned laminate.

[0018] The packaging bag of the present invention is made using the above laminate, The thickness of the heat seal layer is between 20 μm and 60 μm.

[0019] The stand pouch of the present invention is manufactured using the above laminate, The thickness of the heat seal layer is between 50 μm and 200 μm. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a laminate capable of realizing a packaging material having strength and heat resistance as a packaging material and excellent recyclability.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic cross-sectional view showing an embodiment of the laminate of the present invention. [Figure 2] It is a schematic cross-sectional view showing an embodiment of the laminate of the present invention. [Figure 3] It is a schematic cross-sectional view showing an embodiment of the laminate of the present invention. [Figure 4] It is a schematic cross-sectional view showing an embodiment of the laminate of the present invention. [Figure 5] It is a schematic cross-sectional view showing an embodiment of the laminate of the present invention. [Figure 6] It is a perspective view showing an embodiment of a packaging material produced using the laminate of the present invention. [Figure 7] It is a perspective view showing an embodiment of a packaging material produced using the laminate of the present invention.

Modes for Carrying Out the Invention

[0022] <Laminate> The laminate according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the laminate 10 includes a base material 11 and a heat-sealing layer 12. The base material 11 includes 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.

[0023] Also, in one embodiment of the present invention, as shown in FIG. 2, the laminate 10 can include a vapor deposition film 18 between the base material 11 and the heat-sealing layer 12.

[0024] Furthermore, in one embodiment of the present invention, as shown in Figure 3, the laminate 10 may include an adhesive layer 19 between the substrate 11 and the heat seal layer 12 or the vapor-deposited film 18.

[0025] Furthermore, in one embodiment of the present invention, as shown in Figure 4, the laminate 10 may include an intermediate layer 21 between the substrate 11 and the heat seal layer 12, the intermediate layer comprising a vapor-deposited film 18 and a stretched polyethylene film 20.

[0026] Furthermore, in one embodiment of the present invention, as shown in Figure 5, the laminate 10 may include an adhesive layer 19 between the base material 11 and the intermediate layer 21, and between the intermediate layer 21 and the heat seal layer 12.

[0027] In the laminate of the present invention, the polyethylene content is preferably 90% by mass or more. By setting the polyethylene content in the entire laminate of the present invention to 90% by mass or more, the recyclability of the laminate of the present invention can be improved. The polyethylene content in a laminate refers to the ratio of the polyethylene content to the sum of the resin material content in each layer constituting the laminate.

[0028] The following describes each layer that constitutes the laminate of the present invention.

[0029] <Base material> The base material of the laminate of the present invention is made of polyethylene, and the heat-seal layer described below is also made of polyethylene. This configuration improves the recyclability of the laminate.

[0030] The substrate uses a stretched film made of polyethylene, which improves the heat resistance and strength of the laminate. It also improves the printability of the substrate. The stretched film may be either a uniaxially oriented film or a biaxially oriented film.

[0031] The stretching ratio in the longitudinal direction (MD) of the stretched film is preferably 2 times or more and 10 times or less, and preferably 3 times or more and 7 times or less. By setting the stretching ratio in the longitudinal 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. Furthermore, the printability of the substrate can be improved. In addition, the transparency of the substrate can be improved, so when an image is formed on the heat-seal layer side surface of the substrate, its visibility can be improved. On the other hand, there is no particular upper limit to the stretching ratio in the longitudinal direction (MD) of the stretched film, but from the viewpoint of the breaking limit of the stretched film, it is preferable to set it to 10 times or less.

[0032] Furthermore, the stretching ratio in the transverse direction (TD) of the stretched film is preferably 2 times or more and 10 times or less, and preferably 3 times or more and 7 times or less. 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. Furthermore, the printability of the substrate can be improved. In addition, the transparency of the substrate can be improved, so when an image is formed on the heat-seal layer side surface of the substrate, its visibility can be improved. On the other hand, there is no particular upper limit to the stretching ratio in the transverse direction (TD) of the stretched film, but from the viewpoint of the breaking limit of the stretched film, it is preferable to set it to 10 times or less.

[0033] The haze value of the stretched film is preferably 30% or less, and more preferably 20% or less. This improves the transparency of the stretched film. In this invention, the haze value of the stretched film is measured in accordance with JIS K 7105.

[0034] The substrate may have an image formed on its surface. It is preferable that an image be formed on the side where the heat seal layer described below is provided, as this prevents contact with the outside air and prevents deterioration over time. The resulting images are not particularly limited and may represent letters, patterns, symbols, or combinations thereof. Image formation on the substrate is preferably carried out using biomass-derived ink, which makes it possible to produce packaging materials with less environmental impact using the laminate of the present invention. The method of image formation is not particularly limited and can include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing. Among these, flexographic printing is preferred from the viewpoint of environmental impact.

[0035] The substrate of the laminate of the present invention has a structure consisting of a five-layer co-pressed stretched film comprising 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, referred to as the substrate intermediate layer in this paragraph), a medium-density polyethylene layer, and a high-density polyethylene layer. This configuration improves the stretchability of the film. Furthermore, it improves the strength and heat resistance of the laminate of the present invention. Additionally, it prevents curling in the substrate. Furthermore, the production efficiency of the film can be improved as described below. In this case, it is preferable that the thickness of the high-density polyethylene layer is 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 1 / 10 or more, the strength and heat resistance of the laminate of the present invention can be improved. Furthermore, by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer to 1 / 1 or less, the stretchability of the film can be improved. Furthermore, it is preferable that the thickness of the high-density polyethylene layer is the same as or greater than the thickness of the intermediate layer of the base material. The ratio of the thickness of the high-density polyethylene layer to the thickness of the substrate intermediate 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 substrate intermediate layer to 1 / 0.25 or more, heat resistance can be improved. Furthermore, by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the substrate intermediate layer to 1 / 1 or less, the adhesion between 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. Furthermore, 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. Furthermore, 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 substrate intermediate layer 1 μm or more, the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer can be further improved. Furthermore, by making the thickness of the substrate intermediate layer 10 μm or less, the processability of the laminate of the present invention can be further improved.

[0036] In one embodiment, a substrate with such a configuration can be produced, for example, by an inflation method. Specifically, it can be manufactured by co-extruding 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 tube shape from the outside, 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 manufacturing in this manner, the number of defective products in production can be significantly reduced, ultimately improving production efficiency. Furthermore, the inflation film-forming machine can also perform stretching, which further improves production efficiency.

[0037] In the present invention, high-density polyethylene can be polyethylene with a density of 0.945 g / cm³ or higher, medium-density polyethylene can be polyethylene with a density of 0.925 g / cm³ or higher and less than 0.945 g / cm³, low-density polyethylene can be polyethylene with a density of 0.900 g / cm³ or higher and less than 0.925 g / cm³, linear low-density polyethylene can be polyethylene with a density of 0.900 g / cm³ or higher and less than 0.925 g / cm³, and ultra-low-density polyethylene can be polyethylene with a density of less than 0.900 g / cm³.

[0038] Polyethylenes with different densities and branching patterns, as described above, can be obtained by appropriately selecting a polymerization method. For example, it is preferable to use a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as the polymerization catalyst, and to carry out the polymerization in one or more stages using one of the following methods: gas-phase polymerization, slurry polymerization, solution polymerization, or high-pressure ionic polymerization.

[0039] The single-site catalyst described above is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene transition metal compound or a non-metallocene transition metal compound with an activation co-catalyst. Single-site catalysts are preferred over multi-site catalysts because they have a more uniform active site structure, allowing for the polymerization of polymers with high molecular weight and high uniformity. As a single-site catalyst, metallocene catalysts are particularly preferred. A metallocene catalyst is a catalyst comprising a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a co-catalyst, an organometallic compound if necessary, and each catalytic component of a support.

[0040] In the transition metal compounds of Group IV of the periodic table containing the ligand having the cyclopentadienyl skeleton described above, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group, etc. The substituted cyclopentadienyl group has at least one substituent selected from hydrocarbon groups having 1 to 30 carbon atoms, silyl groups, silyl-substituted alkyl groups, silyl-substituted aryl groups, cyano groups, cyanoalkyl groups, cyanoaryl groups, halogen groups, haloalkyl groups, halosilyl groups, etc. The substituted cyclopentadienyl group may have two or more substituents, and the substituents may bond to each other to form a ring, forming an indenyl ring, a fluorenyl ring, an azlenyl ring, or a hydrogenated version thereof. The ring formed by the bonding of substituents may further have substituents on each other.

[0041] In a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, examples of the transition metal include zirconium, titanium, and hafnium, with zirconium and hafnium being particularly preferred. The transition metal compound usually has two ligands having a cyclopentadienyl skeleton, and it is preferable that each ligand having a cyclopentadienyl skeleton is bonded to each other by a bridging group. Examples of bridging groups 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. A substituted silylene group is preferred. The above transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton can be used as a catalyst component, either individually or as a mixture of two or more.

[0042] Co-catalysts are those that can effectively utilize the transition metal compounds of Group IV of the periodic table as polymerization catalysts, or that can balance the ionic charge of the catalytically activated state. Examples of co-catalysts include benzene-soluble aluminoxanes and benzene-insoluble organoaluminum oxy compounds, ion-exchangeable layered silicates, boron compounds, ionic compounds consisting of cations containing or not containing active hydrogen groups and non-coordinating anions, lanthanide salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing fluoro groups.

[0043] Transition metal compounds of Group IV of the periodic table containing ligands having a cyclopentadienyl skeleton may be used by being supported on an inorganic or organic compound. Preferred supports are porous oxides of inorganic or organic compounds, specifically including ion-exchange layered silicates such as montmorillonite, SiO2, Al2O3, MgO, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, ThO2, or mixtures thereof. Further organometallic compounds that may be used as needed include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organoaluminum compounds are preferred.

[0044] Furthermore, copolymers of ethylene and other monomers can be used, as long as they do not impair the properties of the present invention. Examples of ethylene copolymers include copolymers consisting of ethylene and α-olefins having 3 to 20 carbon atoms. 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. Also, copolymers with vinyl acetate or acrylic acid esters, etc., are acceptable, as long as they do not impair the objectives of the present invention.

[0045] Furthermore, in this invention, instead of ethylene obtained from fossil fuels, biomass-derived ethylene may be used as a raw material for obtaining the above-mentioned polyethylene. Since such biomass-derived polyethylene is a carbon-neutral material, it can be used as a packaging material with an even lower environmental impact. Such biomass-derived polyethylene can be manufactured, for example, by a method described in Japanese Patent Application Publication No. 2013-177531. Alternatively, commercially available biomass-derived polyethylene (for example, Green PE, commercially available from Braschem) may be used.

[0046] In addition, recycled polyethylene can be used through mechanical recycling. Mechanical recycling generally involves crushing collected polyethylene film, washing it with alkali to remove dirt and foreign matter from the film surface, and then drying it under high temperature and reduced pressure for a certain period of time to disperse any contaminants remaining inside the film, thereby decontaminating it and removing the dirt from the polyethylene film, returning it to polyethylene once again.

[0047] The base material may contain additives to the extent that they do not impair the properties of the present invention, such as crosslinking agents, antioxidants, antiblocking agents, lubricants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0048] Furthermore, it is preferable that the substrate is surface-treated. This improves adhesion with adjacent layers. The surface treatment method is not particularly limited and includes physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals. Alternatively, an anchor coat layer may be formed on the substrate surface using a conventionally known anchor coat agent.

[0049] 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 substrate thickness 10 μm or more, the strength of the laminate of the present invention can be improved. Furthermore, by making the substrate thickness 50 μm or less, the processability of the laminate of the present invention can be improved.

[0050] The base material can be produced by forming a film from polyethylene using a T-die method or inflation method, and then stretching the film.

[0051] When preparing a substrate using 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 polyethylene MFR to 3g / 10min or more, the processability of the laminate of the present invention can be improved. Furthermore, by setting the polyethylene MFR to 20g / 10min or less, it is possible to prevent the resin film from rupturing.

[0052] When preparing a substrate by the 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 setting the polyethylene MFR to 0.5 g / 10 min or more, the processability of the laminate of the present invention can be improved. Furthermore, by setting the polyethylene MFR to 5 g / 10 min or less, the film-forming properties can be improved.

[0053] Furthermore, the base material is not limited to that prepared by the above method; commercially available materials may also be used.

[0054] <Heat seal layer> The heat-seal layer of the laminate of the present invention is characterized by being made of polyethylene, similar to the base material described above. This configuration makes it possible to create a packaging material that has sufficient strength and heat resistance as a packaging material, and is also recyclable. However, stretched polyethylene film is formed from an unstretched polyethylene resin film or by melt extrusion of polyethylene.

[0055] 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 low-density polyethylene (VLDPE). Copolymers of ethylene and other monomers can be used as long as they do not impair the properties of the present invention. Furthermore, from an environmental perspective, it is preferable that the polyethylene be derived from biomass or recycled polyethylene.

[0056] The heat seal layer may contain the above-mentioned additives to the extent that it does not impair the properties of the present invention.

[0057] In one embodiment, the heat seal layer has a multilayer structure and includes an intermediate layer containing at least one of medium-density polyethylene and high-density polyethylene. Specifically, the structure can consist of a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene; a layer containing at least one of medium-density polyethylene and high-density polyethylene; and a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. By adopting this configuration, it is possible to further improve the suitability for bag making and strength of the laminate of the present invention while maintaining heat sealability.

[0058] In other embodiments, the heat seal layer may consist of a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene / a layer containing biomass-derived polyethylene / a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. By adopting this configuration, the environmental impact of packaging materials and other products made using the laminate of the present invention can be further reduced.

[0059] The thickness of the heat-seal layer is preferably adjusted as appropriate according to the weight of the contents to be filled into the packaging material made from the laminate of the present invention. For example, when preparing a packaging bag 20 as shown in Figure 6, which is filled with contents of 1g or more and 200g or less, the thickness of the heat seal layer is preferably 20μm or more and 60μm or less. By making the heat seal layer 20 μm or thicker, it is possible to prevent the filled contents from leaking due to damage to the heat seal layer. Furthermore, by making the heat seal layer 60 μm or less, the processability of the laminate of the present invention can be improved.

[0060] Furthermore, when preparing a stand pouch 30 as shown in Figure 7, which is filled with contents of 50g or more and 2000g or less, the thickness of the heat seal layer is preferably 50μm or more and 200μm or less. By making the heat seal layer 50 μm or thicker, it is possible to prevent the filled contents from leaking due to damage to the heat seal layer. Furthermore, by making the heat seal layer 200 μm or less thick, the processability of the laminate of the present invention can be improved. Note that the shaded areas in Figures 6 and 7 represent the heat-sealed sections.

[0061] <Vaporized film> The laminate of the present invention may include a vapor-deposited film between the substrate and the heat-seal layer. This improves the gas barrier properties of the laminate, specifically the oxygen barrier properties and water vapor barrier properties.

[0062] Examples of vapor-deposited films include those composed of metals such as aluminum, as well as inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

[0063] Furthermore, the thickness of the deposited film is preferably 1 nm to 150 nm, more preferably 5 nm to 60 nm, and even more preferably 10 nm to 40 nm. By setting the thickness of the vapor-deposited film to 1 nm or more, the oxygen barrier and water vapor barrier properties of the laminate of the present invention can be further improved. Furthermore, by setting the thickness of the vapor-deposited film to 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.

[0064] For the vapor-deposited film to be an aluminum vapor-deposited film, its OD value is preferably between 2 and 3.5. This allows for improved oxygen barrier and water vapor barrier properties while maintaining the productivity of the laminate of the present invention. In this invention, the OD value can be measured in accordance with JIS-K-7361.

[0065] Deposited films can be formed using conventionally known methods, such as physical vapor deposition (PVD) methods including vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods including plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition.

[0066] Furthermore, for example, a composite film consisting of two or more deposited films of different inorganic oxides can be formed and used by combining physical vapor deposition and chemical vapor deposition methods. The vacuum level of the deposition chamber is preferably around 10⁻² to 10⁻⁸ mbar before oxygen introduction and preferably around 10⁻¹ to 10⁻⁶ mbar after oxygen introduction. The amount of oxygen introduced will vary depending on the size of the deposition machine. For the oxygen introduced, inert gases such as argon, helium, and nitrogen may be used as carrier gases within a range that does not cause problems. The film transport speed can be around 10 to 800 m / min.

[0067] It is preferable that the surface of the deposited film is subjected to the above-mentioned surface treatment. This improves adhesion with adjacent layers.

[0068] <Adhesive layer> In one embodiment, the laminate of the present invention may include adhesive layers between any of the layers. This improves the adhesion between these layers.

[0069] The adhesive layer contains at least one type of adhesive, which may be a one-component curing type, a two-component curing type, or a non-curing type. The adhesive may be a solvent-free type or a solvent-based type, but from the viewpoint of environmental impact, a solvent-free type adhesive is preferably used. Examples of solvent-free adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives, and urethane-based adhesives. Among these, two-component curing type urethane-based adhesives are preferably used. 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.

[0070] Furthermore, when an adhesive layer is provided adjacent to a vapor-deposited film, which is an aluminum vapor-deposited film, it is preferable that the adhesive layer be composed of a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphate-modified compound. By configuring the adhesive layer in this way, the oxygen barrier and water vapor barrier properties of the laminate of the present invention can be further improved. Furthermore, when applying laminates with vapor-deposited films to packaging materials, bending loads are applied to the laminate by molding machines, etc., which may cause cracks in the aluminum vapor-deposited film. By using the specific adhesives described above, even if cracks occur in the aluminum vapor-deposited film, the decrease in oxygen barrier properties and water vapor barrier properties can be suppressed.

[0071] Polyester polyols have two or more hydroxyl groups as functional groups in one molecule. Isocyanate compounds, on the other hand, have two or more isocyanate groups as functional groups in one molecule. Polyester polyols have, for example, a polyester structure or a polyester polyurethane structure as their main backbone.

[0072] Specific examples of resin compositions containing polyester polyols, isocyanate compounds, and phosphate-modified compounds include the PASLIM series sold by DIC Corporation.

[0073] The resin composition may further contain plate-like inorganic compounds, coupling agents, cyclodextrins and / or their derivatives.

[0074] 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 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 The following describes each type of polyester polyol.

[0075] The polyester polyol of the first example is a polycondensate obtained by polycondensing a polycarboxylic acid component containing at least one orthophthalic acid and its anhydride with a polyhydric alcohol component containing at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol. In particular, polyester polyols in which orthophthalic acid and its anhydride are present in a proportion of 70 to 100% by mass relative to the total polycarboxylic acid components are preferred.

[0076] The polyester polyol according to the first example requires orthophthalic acid and its anhydride as polycarboxylic acid components, but other polycarboxylic acid components may be copolymerized to the extent that the effects of this embodiment are not impaired. Specifically, examples 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; 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. Among these, succinic acid, 1,3-cyclopentanedicarboxylic acid, and isophthalic acid are preferred. Furthermore, two or more of the above-mentioned polycarboxylic acids may be used.

[0077] As an example of a polyester polyol related to the second example, a polyester polyol having a glycerol skeleton represented by general formula (1) can be mentioned. [ka] In general formula (1), R1, R2, and R3 are each independently either H (hydrogen atom) or a group represented by the following general formula (2). [ka]

[0078] In formula (2), n represents an integer from 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 substituents, 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).

[0079] 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).

[0080] Furthermore, the compound may be a mixture of two or more compounds in which one of R1, R2, or R3 is a group represented by general formula (2), two of R1, R2, or R3 are groups represented by general formula (2), or all of R1, R2, and R3 are groups represented by general formula (2).

[0081] 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 substituents. If X is substituted by a substituent, it may be substituted by one or more substituents, the substituents being bonded to any carbon atom on X that is different from the free radical. Examples of substituents include chloro, bromo, methyl, ethyl, i-propyl, hydroxyl, methoxy, ethoxy, phenoxy, methylthio, phenylthio, cyano, nitro, amino, phthalimide, carboxyl, carbamoyl, N-ethylcarbamoyl, phenyl, and naphthyl groups.

[0082] In general formula (2), Y represents an alkylene group having 2 to 6 carbon atoms, such as an ethylene group, propylene group, butylene group, neopentylene group, 1,5-pentylene group, 3-methyl-1,5-pentylene group, 1,6-hexylene group, methylpentylene group, and dimethylbutylene group. Among these, propylene and ethylene groups are preferred, with ethylene being the most preferred.

[0083] Polyester resin compounds having a glycerol skeleton represented by general formula (1) can be synthesized by reacting glycerol with an aromatic polycarboxylic acid or its anhydride in which the carboxylic acid is substituted in the ortho position, and a polyhydric alcohol component as essential components.

[0084] Examples of aromatic polycarboxylic acids or their anhydrides in which the carboxylic acid is substituted at the ortho position include orthophthalic acid or its anhydride, naphthalene 2,3-dicarboxylic acid or its anhydride, naphthalene 1,2-dicarboxylic acid or its anhydride, anthraquinone 2,3-dicarboxylic acid or its anhydride, and 2,3-anthracenecarboxylic acid or its anhydride. These compounds may have substituents on any carbon atom of the aromatic ring. Examples of substituents include chloro, bromo, methyl, ethyl, i-propyl, hydroxyl, methoxy, ethoxy, phenoxy, methylthio, phenylthio, cyano, nitro, amino, phthalimide, carboxyl, carbamoyl, N-ethylcarbamoyl, phenyl, and naphthyl groups.

[0085] Furthermore, examples of polyhydric alcohol components include alkylenediols having 2 to 6 carbon atoms. Examples of diols include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, and dimethylbutanediol.

[0086] The polyester polyol in the third example is a polyester polyol having an isocyanuric ring represented by the following general formula (3). [ka] In general formula (3), R1, R2, and R3 each independently represent either "-(CH2)n1-OH (where n1 is an integer from 2 to 4)" or the structure of general formula (4). [ka]

[0087] In general formula (4), n2 represents an integer from 2 to 4, n3 represents an integer from 1 to 5, X represents an arylene group selected from the group consisting of 1,2-phenylene, 1,2-naphthylene, 2,3-naphthylene, 2,3-anthraquinonediyl, and 2,3-anthracenediyl groups, which may have substituents, 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 general formula (4).

[0088] In general formula (3), the alkylene group represented by -(CH2)n1- may be linear or branched. n1 is preferably 2 or 3, with 2 being the most preferred.

[0089] In general formula (4), n² represents an integer between 2 and 4, and n³ represents an integer between 1 and 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 substituents.

[0090] If X is substituted by a substituent, it may be substituted by one or more substituents, the substituents being bonded to any carbon atom on X that is different from the free radical. Examples of substituents include chloro, bromo, methyl, ethyl, i-propyl, hydroxyl, methoxy, ethoxy, phenoxy, methylthio, phenylthio, cyano, nitro, amino, phthalimide, carboxyl, carbamoyl, N-ethylcarbamoyl, phenyl, and naphthyl groups. The substituents of X are preferably hydroxyl, cyano, nitro, amino, phthalimide, carbamoyl, N-ethylcarbamoyl, and phenyl groups, with hydroxyl, phenoxy, cyano, nitro, phthalimide, and phenyl groups being the most preferred.

[0091] In general formula (4), Y represents an alkylene group having 2 to 6 carbon atoms, such as an ethylene group, propylene group, butylene group, neopentylene group, 1,5-pentylene group, 3-methyl-1,5-pentylene group, 1,6-hexylene group, methylpentylene group, and dimethylbutylene group. Among these, propylene and ethylene groups are preferred, with ethylene being the most preferred.

[0092] In general formula (3), at least one of R1, R2, and R3 is a group represented by general formula (4). In particular, it is preferable that all of R1, R2, and R3 are groups represented by general formula (4).

[0093] Furthermore, the compound may be a mixture of two or more compounds in which one of R1, R2, or R3 is a group represented by general formula (4), two of R1, R2, or R3 are groups represented by general formula (4), or all of R1, R2, and R3 are groups represented by general formula (4).

[0094] Polyester polyols having an isocyanuric ring, represented by general formula (3), can be synthesized by reacting a triol having an isocyanuric ring with an aromatic polycarboxylic acid or its anhydride in which the carboxylic acid is substituted in the ortho position, and a polyhydric alcohol component as essential components.

[0095] Examples of triols having an isocyanuric ring include alkylene oxide adducts of isocyanuric acids such as 1,3,5-tris(2-hydroxyethyl)isocyanuric acid and 1,3,5-tris(2-hydroxypropyl)isocyanuric acid.

[0096] Furthermore, examples of aromatic polycarboxylic acids or their anhydrides in which the carboxylic acid is substituted at the ortho position include orthophthalic acid or its anhydride, naphthalene 2,3-dicarboxylic acid or its anhydride, naphthalene 1,2-dicarboxylic acid or its anhydride, anthraquinone 2,3-dicarboxylic acid or its anhydride, and 2,3-anthracenecarboxylic acid or its anhydride. These compounds may have substituents on any carbon atom of the aromatic ring.

[0097] Examples of substituents include chloro group, bromo group, methyl group, ethyl group, i-propyl group, hydroxyl group, methoxy group, ethoxy group, phenoxy group, methylthio group, phenylthio group, cyano group, nitro group, amino group, phthalimide group, carboxyl group, carbamoyl group, N-ethylcarbamoyl group, phenyl group, and naphthyl group.

[0098] Furthermore, examples of polyhydric alcohol components include alkylenediols having 2 to 6 carbon atoms. Examples include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, and dimethylbutanediol. In particular, polyester polyol compounds having an isocyanuric ring are preferred when 1,3,5-tris(2-hydroxyethyl)isocyanuric acid or 1,3,5-tris(2-hydroxypropyl)isocyanuric acid is used as the triol compound having an isocyanuric ring, an aromatic polycarboxylic acid in which the carboxylic acid is substituted at the ortho position or orthophthalic anhydride is used as the anhydride, and ethylene glycol is used as the polyhydric alcohol, as these compounds exhibit particularly excellent oxygen barrier properties and adhesion.

[0099] The isocyanuric ring is highly polar and trifunctional, which can increase the overall polarity of the system and increase the crosslinking density. From this viewpoint, it is preferable to contain 5% by mass or more of the isocyanuric ring relative to the total solid content of the adhesive resin.

[0100] Isocyanate compounds have two or more isocyanate groups in their molecule. Furthermore, the isocyanate compound may be aromatic or aliphatic, and may be a low-molecular-weight compound or a high-molecular-weight compound. Furthermore, the isocyanate compound may be a blocked isocyanate compound obtained by an addition reaction using a known isocyanate blocking agent by a known and conventional method. In particular, polyisocyanate compounds having three or more isocyanate groups are preferred from the viewpoint of adhesion and retort resistance, and aromatic compounds are preferred from the viewpoint of oxygen barrier properties and water vapor barrier properties.

[0101] Specific examples of isocyanate compounds include, for example, 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, burettes, 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 high molecular weight active hydrogen compounds of various polyester resins, polyether polyols, and polyamides.

[0102] Phosphate-modified compounds are, for example, compounds represented by the following general formulas (5) or (6). [ka] 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, an optionally substituted phenyl group, and an alkyl group having 1 to 4 carbon atoms, but at least one of them is a hydrogen atom, and n represents an integer from 1 to 4. [ka] 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, an optionally substituted phenyl group, and an alkyl group having 1 to 4 carbon atoms with a (meth)acryloyloxy group, where n is an integer from 1 to 4, x is an integer from 0 to 30, and y is an integer from 0 to 30, except when both x and y are 0.

[0103] More specifically, examples include phosphoric acid, pyrophosphate, triphosphate, 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.

[0104] The content of the phosphate-modified compound in the resin composition is preferably 0.005% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 1% by mass or less. By setting the content of the phosphate-modified compound to 0.005% by mass or more, the oxygen barrier and water vapor barrier properties of the laminate of the present invention can be improved. Furthermore, by setting the content of the phosphate-modified compound to 10% by mass or less, the adhesion of the adhesive layer can be improved.

[0105] The resin composition containing polyester polyol, isocyanate compound, and phosphate-modified compound may also contain plate-like inorganic compound, which can improve the adhesion of the adhesive layer. Furthermore, it can improve the bending load resistance of the laminate of the present invention. Examples of plate-like inorganic compounds include kaolinite-serpentine clay minerals (haloysite, kaolinite, endelite, dickite, nacrite, antigorite, chrysotile, etc.) and pyrophyllite-talc group minerals (pyrophyllite, talc, kerolite, etc.).

[0106] Examples of coupling agents include silane-based coupling agents, titanium-based coupling agents, and aluminum-based coupling agents represented by the general formula (7) below. These coupling agents may be used individually or in combination of two or more types. [ka]

[0107] 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( Examples include aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-triethoxysilyl-N-(1,3-dimethylbutylidene).

[0108] 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 dimethacrylate isostearoyl titanate, isopropyl isostearoyl diacrylic titanate, diisostearoylethylene titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and dicumylphenyl oxyacetate titanate.

[0109] Specific examples of aluminum-based coupling agents include, for example, acetalkoxyaluminum diisopropylate, diisopropoxyaluminum ethyl acetacetate, diisopropoxyaluminum monomethacrylate, isopropoxyaluminum alkyl acetacetate mono(dioctyl phosphate), aluminum-2-ethylhexanoate oxide trimer, aluminum stearate oxide trimer, and alkyl acetacetate aluminum oxide trimer.

[0110] The resin composition may contain cyclodextrin and / or its derivatives, thereby improving the adhesion of the adhesive layer. Furthermore, the bending load resistance of the laminate of the present invention can be further improved. Specifically, for example, cyclodextrins such as alkylated cyclodextrins, acetylated cyclodextrins, and hydroxyalkylated cyclodextrins, in which the hydrogen atom of the hydroxyl group of the glucose unit of a cyclodextrin is substituted with another functional group, can be used. Branched cyclic dextrins can also be used. Furthermore, the cyclodextrin skeleton in cyclodextrins and cyclodextrin derivatives may be any of the following: α-cyclodextrin consisting of 6 glucose units, β-cyclodextrin consisting of 7 glucose units, or γ-cyclodextrin consisting of 8 glucose units. These compounds may be used individually or in combination of two or more. Furthermore, these cyclodextrins and / or their derivatives may collectively be referred to as dextrin compounds from now on.

[0111] From the viewpoint of compatibility and dispersibility with resin compositions, it is preferable to use cyclodextrin derivatives as the cyclodextrin compound.

[0112] Examples of alkylated cyclodextrins include methyl-α-cyclodextrin, methyl-β-cyclodextrin, and methyl-γ-cyclodextrin. These compounds may be used individually or in combination of two or more.

[0113] Examples of acetylated cyclodextrins include monoacetyl-α-cyclodextrin, monoacetyl-β-cyclodextrin, and monoacetyl-γ-cyclodextrin. These compounds may be used individually or in combination of two or more.

[0114] Examples of hydroxyalkylated cyclodextrins include hydroxypropyl-α-cyclodextrin, hydroxypropyl-β-cyclodextrin, and hydroxypropyl-γ-cyclodextrin. These compounds may be used individually or in combination of two or more.

[0115] 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 adhesion of the adhesive layer can be improved. Furthermore, when an adhesive layer made of a cured resin composition containing a polyester polyol, an isocyanate compound, and a phosphate-modified compound is provided adjacent to an aluminum vapor-deposited film, the bending load resistance of the laminate can be improved. By reducing the thickness of the adhesive layer to 6 μm or less, the processability of the laminate can be improved.

[0116] The adhesive layer can be formed by applying and drying it on a substrate or the like using conventionally known methods such as the direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, fontein method, and transfer roll coating method.

[0117] <Middle class> In one embodiment, the laminate of the present invention may include an intermediate layer between the substrate and the heat-seal layer, which is made of a stretched polyethylene film having a vapor-deposited film on one side. This can further improve the strength, oxygen barrier properties, and water vapor barrier properties of the laminate.

[0118] (Vaporized film) The intermediate layer comprises a vapor-deposited film, which improves gas barrier properties, particularly oxygen barrier properties and water vapor barrier properties.

[0119] Examples of vapor-deposited films include those composed of metals such as aluminum, as well as inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

[0120] Furthermore, the thickness of the deposited film is preferably 1 nm to 150 nm, more preferably 5 nm to 60 nm, and even more preferably 10 nm to 40 nm. By setting the thickness of the vapor-deposited film to 1 nm or more, the oxygen barrier and water vapor barrier properties of the laminate of the present invention can be further improved. Furthermore, by setting the thickness of the vapor-deposited film to 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.

[0121] For the vapor-deposited film to be an aluminum vapor-deposited film, its OD value is preferably between 2 and 3.5. This allows for improved oxygen barrier and water vapor barrier properties while maintaining the productivity of the laminate of the present invention. In this invention, the OD value can be measured in accordance with JIS-K-7361.

[0122] The vapor-deposited film can be formed by the method described above.

[0123] It is preferable that the surface of the deposited film is subjected to the above-mentioned surface treatment. This improves adhesion with adjacent layers.

[0124] (Stretched polyethylene film) The stretched polyethylene film constituting the intermediate layer is characterized by being made of polyethylene, similar to the base material and heat-seal layer described above. This configuration makes it possible to create a recyclable packaging material while maintaining the strength and heat resistance required for packaging.

[0125] Stretched polyethylene film is used to improve the strength and heat resistance of the packaging material. The stretched film may be uniaxially oriented or biaxially oriented.

[0126] The stretching ratio in the longitudinal direction (MD) of the stretched film is preferably 2 times or more and 10 times or less, and preferably 3 times or more and 7 times or less. By setting the stretching ratio in the longitudinal 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, there is no particular upper limit to the stretching ratio in the longitudinal direction (MD) of the stretched film, but from the viewpoint of the breaking limit of the stretched film, it is preferable to set it to 10 times or less.

[0127] Furthermore, the stretching ratio in the transverse direction (TD) of the stretched film is preferably 2 times or more and 10 times or less, and preferably 3 times or more and 7 times or less. 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, there is no particular upper limit to the stretching ratio in the transverse direction (TD) of the stretched film, but from the viewpoint of the breaking limit of the stretched film, it is preferable to set it to 10 times or less.

[0128] Among the polyethylenes included in the stretched polyethylene film, high-density polyethylene and medium-density polyethylene are preferred from the viewpoint of strength, heat resistance, and suitability for stretching the film, and medium-density polyethylene is more preferred from the viewpoint of suitability for stretching. Furthermore, the intermediate layer may also consist of the multilayer structure described above, similar to the base material.

[0129] The stretched polyethylene film may contain the above-mentioned additives to the extent that it does not impair the properties of the present invention.

[0130] 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. Furthermore, 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.

[0131] The stretched polyethylene film may be one produced by the T-die method or inflation method described above, or it may be one that is commercially available.

[0132] <Application> The laminate of the present invention can be used particularly suitably for packaging material applications. The packaging material is not particularly limited and may be a packaging bag 30 as shown in Figure 6, or a stand pouch 40 having a body 41 and a bottom 42 as shown in Figure 7. In the case of a stand pouch, only the body may be formed from the laminate, only the bottom may be formed from the laminate, or both the body and the bottom may be formed from the laminate.

[0133] The packaging bag can be manufactured by folding the laminated material in half and overlapping the two halves so that the heat-sealed layer faces inward, and then heat-sealing the edges. Alternatively, the packaging bag can also be manufactured by overlapping two laminated materials so that the heat-seal layers face each other, and then heat-sealing the edges.

[0134] A stand-up pouch can be manufactured by first forming the body of the laminated material by heat-sealing it in a cylindrical shape with the heat-seal layer facing inward, and then forming the bottom by folding the laminated material in a V-shape with the heat-seal layer facing inward, sandwiching it from one end of the body, and heat-sealing it.

[0135] The heat sealing method is not particularly limited and can be carried out by known methods such as bar seals, rotary roll seals, belt seals, impulse seals, high-frequency seals, and ultrasonic seals.

[0136] The contents to be filled into the packaging material are not particularly limited and may be liquids, powders, or gels. They may also be food products or non-food products. After filling with contents, the opening can be heat-sealed to create a package. [Examples]

[0137] The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0138] <Example 1-1> High-density polyethylene (density: 0.960 g / cm³, melting point: 130°C, MFR: 0.85 g / 10 min, manufactured by Dowchemical, product name: Elite 5960), medium-density polyethylene (density: 0.940 g / cm³, melting point: 126°C, MFR: 0.85 g / 10 min, manufactured by Dowchemical, product name: Elite 5940), and ultra-low-density polyethylene (density: 0.870 g / cm³, melting point: 55°C, MFR: 1.0 g / 10 min, manufactured by Dowchemical, product name: Affinity) EG8100G) was extruded by inflation molding as a tubular film comprising 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. Then, the inner ultra-low-density polyethylene layers were pressed together with rubber rolls to obtain a polyethylene film with a thickness of 125 μm comprising 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 with a thickness of 25 μm. The haze value of substrate A was measured in accordance with JIS K 7105, and it was found to be 6.2%.

[0139] An image was formed on one side of substrate A using gravure printing with oil-based gravure ink (manufactured by DIC Graphics Co., Ltd., product name: Finart).

[0140] Linear low-density polyethylene A (density: 0.923 g / cm³, melting point 121°C, MFR: 1.5 g / 10 min, manufactured by Prime Polymer, trade name: SP2510) and a mixture of linear low-density polyethylene A and biomass-derived polyethylene (density: 0.916 g / cm³, MFR: 1.3 g / 10 min, biomass content: 87%, manufactured by Blaschem, trade name: SLL118) (2:8 (by mass)) and linear low-density polyethylene B (density: 0 A 50 μm thick heat seal layer A was fabricated by inflation molding using (0.913 g / cm³, melting point 116°C, MFR: 2.0 g / 10 min, manufactured by Prime Polymer Co., Ltd., product name: SP1520) and a 17 μm thick linear low-density polyethylene A layer, 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.

[0141] The image-forming surface of the above-mentioned substrate A and the layer made of linear low-density polyethylene A of the above-mentioned heat-seal layer A were laminated together via a two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-77T / H-7) to obtain the laminate of the present invention. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 95% by mass.

[0142] <Comparative Example 1-1> The above-mentioned high-density polyethylene, medium-density polyethylene, and ultra-low-density polyethylene were extruded from the outside as a tubular film comprising a high-density polyethylene layer, a medium-density polyethylene layer, and an ultra-low-density polyethylene layer by an inflation molding method. Then, the inner ultra-low-density polyethylene layers were pressed together with a rubber roll to obtain a substrate a with a thickness of 25 μm, comprising a high-density polyethylene layer (2.5 μm), a medium-density polyethylene layer (8.75 μm), an ultra-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 substrate a was measured in accordance with JIS K 7105, and the haze value was 21.3%.

[0143] An image was formed on one surface of substrate a using the above-mentioned oil-based gravure ink by gravure printing.

[0144] The image-forming surface of the substrate a and the layer made of linear low-density polyethylene A of the heat-seal layer A were laminated together via the two-component curable urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 95% by mass.

[0145] <Comparative Example 1-2> A laminate was prepared in the same manner as in Example 1-1, except that the base material A was changed to a 12 μm thick biaxially oriented PET film (manufactured by Toyobo Co., Ltd., product name: E5100). Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 75% by mass.

[0146] <Example 2-1> The above-mentioned base material A was prepared.

[0147] An image was formed on one side of substrate A using gravure printing with oil-based gravure ink (manufactured by DIC Graphics Co., Ltd., product name: Finart).

[0148] A 100 μm thick heat-seal layer B was fabricated by forming a film using the above-mentioned linear low-density polyethylene A, a mixture of the above-mentioned linear low-density polyethylene A and the above-mentioned biomass-derived polyethylene (2:8 (by mass)), and the above-mentioned linear low-density polyethylene B by inflation molding. This layer comprises 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.

[0149] 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 together via the two-component curable urethane adhesive to obtain the laminate of the present invention. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 97% by mass.

[0150] <Comparative Example 2-1> The above-mentioned base material a was prepared.

[0151] An image was formed on one surface of substrate a using the above-mentioned oil-based gravure ink by gravure printing.

[0152] 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 together via the two-component curable urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 97% by mass.

[0153] <Comparative Example 2-2> A laminate was prepared in the same manner as in Example 2-1, except that the base material A was changed to the above-mentioned biaxially oriented PET film with a thickness of 12 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 86% by mass.

[0154] <Example 3-1> The above-mentioned base material A was prepared.

[0155] An image was formed on one side of substrate A using gravure printing with oil-based gravure ink (manufactured by DIC Graphics Co., Ltd., product name: Finart).

[0156] A heat-seal layer A was prepared, and a 20 nm thick aluminum vapor-deposited film was formed on this linear low-density polyethylene A by PVD (Physical Vapor Deposition).

[0157] The image-forming surface of substrate A and the vapor-deposited surface of heat-seal layer A were laminated together via the above-mentioned two-component curable urethane adhesive to obtain the laminate of the present invention. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 95% by mass.

[0158] <Example 3-2> In Example 3-1, the laminate of the present invention was fabricated in the same manner as in Example 3-1, except that the image-forming surface of the substrate A and the vapor-deposited surface of the heat-seal layer A were bonded using a two-component curing adhesive containing an isocyanate compound and a phosphate-modified compound (PASLIM VM001 / VM102CP, manufactured by DIC Corporation).

[0159] <Comparative Example 3-1> The above-mentioned base material a was prepared.

[0160] An image was formed on one surface of substrate a using the above-mentioned oil-based gravure ink by gravure printing.

[0161] A heat-seal layer A was prepared, and a 20 nm thick aluminum vapor-deposited film was formed on this linear low-density polyethylene A by PVD (Physical Vapor Deposition).

[0162] The image-forming surface of substrate a and the vapor-deposited surface of heat-seal layer A were laminated together via the above-mentioned two-component curable urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 95% by mass.

[0163] <Comparative Example 3-2> A laminate was prepared in the same manner as in Example 3-1, except that the base material A was changed to the above-mentioned biaxially oriented PET film with a thickness of 12 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 76% by mass.

[0164] <Example 4-1> The above-mentioned base material A was prepared.

[0165] An image was formed on one side of substrate A using gravure printing with oil-based gravure ink (manufactured by DIC Graphics Co., Ltd., product name: Finart).

[0166] The above medium-density polyethylene was formed by inflation molding to obtain a polyethylene film with a thickness of 100 μm. Then, it was stretched in the longitudinal direction (MD) at a stretching ratio of 5 times to obtain a stretched polyethylene film A with a thickness of 20 μm. Next, an aluminum vapor-deposited film with a thickness of 20 nm was formed on one side of the stretched polyethylene film A by PVD to obtain an intermediate layer A.

[0167] The image-forming surface of substrate A was laminated onto the vapor-deposited surface of intermediate layer A via the two-component curing urethane adhesive. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm.

[0168] A heat-seal layer A was prepared. Next, a layer of linear low-density polyethylene A of the heat-seal layer A was laminated to the non-deposited surface of the intermediate layer A via the above-mentioned two-component curable urethane adhesive to obtain the laminate of the present invention. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 93% by mass.

[0169] <Example 4-2> In Example 4-1, the laminate of the present invention was fabricated 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 using a two-component curing adhesive containing an isocyanate compound and a phosphate-modified compound (PASLIM VM001 / VM102CP, manufactured by DIC Corporation).

[0170] <Comparative Example 4-1> The above-mentioned base material a was prepared.

[0171] An image was formed on one side of substrate a using gravure printing with oil-based gravure ink (manufactured by DIC Graphics Co., Ltd., product name: Finart).

[0172] The above medium-density polyethylene was formed into a film by inflation molding to obtain a stretched polyethylene film a with a thickness of 20 μm. Next, an aluminum vapor-deposited film with a thickness of 20 nm was formed on one side of the stretched polyethylene film a by PVD to obtain an intermediate layer a.

[0173] The image-forming surface of substrate a was laminated onto the vapor-deposited surface of intermediate layer a via the two-component curing urethane adhesive. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm.

[0174] A heat-seal layer A was prepared, and this layer made of linear low-density polyethylene A was laminated to the non-deposited surface of the intermediate layer a via the two-component curable urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. Furthermore, the proportion of polyethylene in the laminate obtained in this manner was 93% by mass.

[0175] <Comparative Example 4-2> A laminate was obtained in the same manner as in Example 4-1, except that the stretched polyethylene film of base material A and intermediate layer A was changed to a biaxially oriented polyester film with a thickness of 12 μm (Toyobo Co., Ltd. product name: E5100). The proportion of polyethylene in the laminate obtained in this manner was 62% by mass.

[0176] <Recyclability Assessment> 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) ○: The polyethylene content in the laminate was 90% by mass or more. ×: The polyethylene content in the laminate was less than 90% by mass.

[0177] <Heat resistance evaluation> Two test specimens measuring 80 mm in length and 80 mm in width were prepared from 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 placed on top of each other with the heat-seal layers facing each other, and three sides were heat-sealed at 140°C to create a packaging bag. Two test specimens measuring 110 mm in length and 150 mm in width were prepared from the laminates obtained in Example 2-1 and Comparative Examples 2-1 to 2-2. Two test pieces were placed on top of each other with the heat-sealed 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. This piece was folded into a V-shape with the heat-sealed layer facing outwards, and heat-sealed to the cylindrical body at 140°C to form the bottom and create a stand-up pouch. The prepared packaging materials were visually inspected and evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1-4. (Evaluation Criteria) ○: No wrinkles or other defects were observed on the surface of the packaging material, and no adhesion to the heat seal bar was observed. ×: Wrinkles and other defects were present on the surface of the packaging material, and it was also found to be adhering to the heat seal bar, making it impossible to manufacture bags.

[0178] <Printability Evaluation> The images formed on the substrates of the laminates prepared 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) ○: The dimensional stability during printing was good, and a good image was formed without smudging or bleeding. ×: The film expanded and contracted during printing, resulting in smudging and blurring of the resulting image.

[0179] <Rigidity Evaluation> The laminates prepared in the above examples and comparative examples were prepared as 10 mm wide test specimens, and their rigidity was measured using a loop stiffness tester (manufactured by Toyo Seiki Seisakusho, product name: Loop Stiffness Tester). The loop length was set to 60 mm. The measurement results are summarized in Tables 1 to 4.

[0180] <Strength Test> The laminates prepared in the above examples and comparative examples were tested for their strength when pierced with a 0.5 mm diameter needle using a tensile testing machine (Orientec Co., Ltd., product name: RTC-1310A). The piercing speed was set to 50 mm / min. The measurement results are summarized in Tables 1 to 4.

[0181] <Flexural load resistance test> First, the oxygen permeability and water vapor permeability of the laminates obtained in 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 measured. Oxygen permeability was measured using a MOCON OXTRAN2 / 20 under conditions of 23°C and 90% RH, while water vapor permeability was measured using a MOCON PERMATRAN3 / 31 under conditions of 40°C and 90% RH. Furthermore, the laminates obtained in 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 using a Gelboflex tester (manufactured by Tester Industries Co., Ltd., product name: BE1006BE) in accordance with ASTM F 392. After bending, the oxygen and water vapor permeability of the laminate was measured. Tables 3 and 4 show the oxygen and water vapor permeability of the laminate before and after the bending load test.

[0182] [Table 1]

[0183] [Table 2]

[0184] [Table 3]

[0185] [Table 4] [Explanation of Symbols]

[0186] 10: Laminate, 11: Substrate, 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-deposited film, 19: Adhesive layer, 20: Stretched polyethylene film, 21: Intermediate layer, 30: Packaging bag, 40: Stand-up pouch, 41: Body, 42: Bottom

Claims

1. A laminate comprising at least a base material 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. The surface of the aforementioned substrate is subjected to a printing process, The aforementioned substrate is made of a co-pressed stretched film, The aforementioned co-pressed stretched film, Density is 0.945 g / cm³ ３ The layer containing high-density polyethylene as described above, Density is 0.925 g / cm³ ３ 0.945g / cm or more ３ A layer containing medium-density polyethylene which is less than, Density is 0.900 g / cm³ ３ 0.925g / cm or more ３ A layer comprising at least one selected from low-density polyethylene with a density of less than 0.900 g / cm³, linear low-density polyethylene with a density of 0.900 g / cm³ or more and less than 0.925 g / cm³, and ultra-low-density polyethylene with a density of less than 0.900 g / cm³, Density is 0.925 g / cm³ ３ 0.945g / cm or more ３ A layer containing medium-density polyethylene which is less than, Density is 0.945 g / cm³ ３ The layer containing high-density polyethylene as described above, Equipped with, A laminate characterized by further comprising an intermediate layer between the substrate and the heat-seal layer, the intermediate layer being made of a stretched polyethylene film having a vapor-deposited film on one side.

2. The laminate according to claim 1, further comprising an adhesive layer between the substrate and the intermediate layer, and between the intermediate layer and the heat seal layer.

3. The aforementioned vapor-deposited film is an aluminum vapor-deposited film. The laminate according to claim 2, 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 phosphate-modified compound.

4. The laminate according to any one of claims 1 to 3, wherein the substrate is manufactured by the inflation method.

5. A laminate according to any one of claims 1 to 4, used for packaging material applications.

6. A packaging material made using a laminate according to any one of claims 1 to 5.

7. It is a packaging bag, Made using the laminate described in any one of claims 1 to 5, A packaging bag characterized in that the thickness of the heat-seal layer is 20 μm or more and 60 μm or less.

8. It is a stand-up pouch, Made using the laminate described in any one of claims 1 to 5, A stand-up pouch characterized in that the thickness of the heat-seal layer is 50 μm or more and 200 μm or less.

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