Laminate, packaging material, packaging bag and stand-up pouch

Abstract

To provide a laminate that can realize a packaging material having sufficient strength, heat resistance and barrier properties applicable to packaging materials and the like, and also excellent recyclability. [Solution] A laminate comprising a substrate, an adhesive layer, and a heat-sealing layer, wherein the substrate and the heat-sealing layer are made of polyethylene, a vapor-deposited film is provided between the heat-sealing layer and the adhesive layer, the substrate is made of a stretched film, at least one surface of the substrate is printed, and the printed layer of the substrate contains at least one of high-density polyethylene and medium-density polyethylene.

Description

[Technical Field]

[0001] The present invention relates to a laminate, a packaging material, a packaging bag, and a stand-up pouch each made from the laminate. [Background technology]

[0002] Conventionally, packaging materials and the like have been produced using resin films made of resin materials. For example, resin films made of polyethylene have moderate flexibility and transparency, as well as excellent heat-sealing properties, and are therefore widely used as packaging materials.

[0003] Normally, resin films made of polyethylene cannot be used as a base material because they are inferior in strength and heat resistance, and are instead used by laminating them with resin films made of polyester, polyamide, etc. Therefore, ordinary packaging materials are made of laminated films in which the base material and heat seal layer are made of different types of resin materials (for example, Patent Document 1).

[0004] In recent years, along with the growing demand for the creation of a recycling-oriented society, there has been a demand for packaging materials with high recyclability. However, as described above, conventional packaging bodies are made of different types of resin materials, and because it is difficult to separate the resin materials, they are not currently recycled. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-202519 Summary of the Invention [Problem to be solved by the invention]

[0006] The present 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 this substrate with a heat seal layer made of polyethylene, it is possible to produce packaging materials and the like that have sufficient strength and heat resistance and are recyclable. Furthermore, the present inventors have found that by further providing a vapor-deposited film on the laminate of the present invention, it is possible to produce a packaging material or the like that has excellent barrier properties, particularly oxygen barrier properties and water vapor barrier properties, while maintaining its recyclability.

[0007] 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, heat resistance, and barrier properties to be applicable as a packaging material, and that also has excellent recyclability. Another problem to be solved by the present invention is to provide a packaging material made 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. [Means for solving the problem]

[0008] In a first embodiment of the present invention, a laminate includes a substrate, an adhesive layer, and a heat seal layer, the substrate and the heat seal layer are made of polyethylene; a vapor-deposited film is provided between the substrate and the adhesive layer and / or between the heat seal layer and the adhesive layer; The substrate is characterized by being made of a stretched film made of polyethylene.

[0009] In a second embodiment of the present invention, a laminate comprises a substrate, a first adhesive layer, an intermediate layer, a second adhesive layer, and a heat seal layer, the substrate, the intermediate layer and the heat seal layer are made of polyethylene; a vapor-deposited film is provided between the substrate and the first adhesive layer, between the first adhesive layer and the intermediate layer, and between the heat seal layer and the second adhesive layer; The substrate and the intermediate layer are characterized by being made of a stretched film made of polyethylene.

[0010] 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.

[0011] In one embodiment of the present invention, the substrate comprises a medium density polyethylene layer.

[0012] In one embodiment of the present invention, the substrate has a structure consisting of a three-layer co-extruded film of a high-density polyethylene layer, a medium-density polyethylene layer, and a high-density polyethylene layer.

[0013] In one embodiment of the present invention, the polyethylene content in the entire laminate is 90% by mass or more.

[0014] In one embodiment of the present invention, the laminate is used in packaging applications.

[0015] The packaging material of the present invention is characterized by being produced using the above laminate.

[0016] 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.

[0017] 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. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a laminate that can realize a packaging material that has the strength, heat resistance and barrier properties required for a packaging material and also has excellent recyclability. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional schematic view showing one embodiment of a laminate of the present invention. [Figure 2] 1 is a cross-sectional schematic view showing one embodiment of a laminate of the present invention. [Figure 3] 1 is a cross-sectional schematic view showing one embodiment of a laminate of the present invention. [Figure 4] 1 is a perspective view showing one embodiment of a packaging material produced using a laminate of the present invention. [Figure 5] 1 is a perspective view showing one embodiment of a packaging material produced using a laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Laminate> The laminate according to the present invention will be described with reference to the drawings. In a first embodiment of the present invention, as shown in Figures 1 and 2, a laminate 10 includes a substrate 11, an adhesive layer 12, and a heat seal layer 13, and includes a vapor-deposited film 14 at least either between the substrate 11 and the adhesive layer 12 or between the heat seal layer 13 and the adhesive layer 12.

[0021] In addition, in a second embodiment of the present invention, as shown in Figure 2, the laminate 10 comprises a substrate 11, an adhesive layer 12, an intermediate layer 15, a second adhesive layer 16, and a heat seal layer 13, and comprises a vapor-deposited film 14 at least between the substrate 11 and the adhesive layer 12, between the adhesive layer 12 and the intermediate layer 15, and between the heat seal layer 13 and the second adhesive layer 16.

[0022] In the laminate of the present invention, the polyethylene content is preferably 90% by mass or more. By making the polyethylene content 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.

[0023] Each layer constituting the laminate of the present invention will be described below.

[0024] <Base material> 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 using such a configuration, the recyclability of the laminate can be improved.

[0025] The substrate is a stretched polyethylene film, 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.

[0026] 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 stretching the stretched film at a stretch ratio of 2 or more in the machine direction (MD), the strength and heat resistance of the laminate of the present invention can be improved. Furthermore, the printability of the substrate can be improved. Furthermore, the transparency of the substrate can be improved, thereby improving the visibility of an image formed on the surface of the substrate facing the heat seal layer. Meanwhile, the upper limit of the stretch ratio in the machine direction (MD) of the stretched film is not particularly limited, but is preferably 10 or less from the viewpoint of the breaking limit of the stretched film.

[0027] The stretching ratio in the transverse direction (TD) 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 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. Furthermore, since the transparency of the substrate can be improved, when an image is formed on the surface of the substrate on the heat seal layer side, 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.

[0028] 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.

[0029] The substrate may have an image formed on its surface. It is preferable that the image be formed on the surface on which the 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, and by using the laminate of the present invention, it is possible to produce packaging materials with a lower environmental impact. The method for forming the image is not particularly limited, and examples thereof 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.

[0030] The polyethylene contained in the substrate may be high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very low-density polyethylene (VLDPE). Here, the high density polyethylene has a density of 0.945 g / cm 3 The polyethylene having a density of 0.925 g / cm or more can be used. 3 More than 0.945g / cm 3 Low density polyethylene can be used, and low density polyethylene is polyethylene with a density of 0.900 g / cm 3 More than 0.925g / cm 3 Polyethylenes with a density of less than 0.900 g / cm can be used, and linear low-density polyethylenes with a density of less than 0.900 g / cm can be used. 3 More than 0.925g / cm 3 Polyethylene with a density of less than 0.900 g / cm can be used, and ultra-low density polyethylene has a density of 0.900 g / cm 3 Less than 100% polyethylene can be used. Among these, high density polyethylene and medium density polyethylene are preferred from the viewpoints of printability, strength, and heat resistance of the laminate of the present invention, and suitability for stretching the film, and medium density polyethylene is more preferred from the viewpoint of suitability for stretching.

[0031] In one embodiment, the substrate may have a structure including a layer made of high-density polyethylene (hereinafter referred to as high-density polyethylene layer) and a layer made of medium-density polyethylene (hereinafter referred to as medium-density polyethylene layer). By providing a high-density polyethylene layer on the outer side of the substrate, the strength and heat resistance of the laminate of the present invention can be further improved, and by providing a medium-density polyethylene layer, the stretchability of the resin film constituting the substrate can be further improved.

[0032] For example, it has a structure consisting of a co-extruded film of a high density polyethylene layer and a medium density polyethylene layer from the outside. By adopting such a constitution, the stretchability of the film can be improved, and the strength and heat resistance of the laminate of the present invention can be improved. 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 further 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 resin film can be further improved.

[0033] Alternatively, for example, the film may be constructed from a three-layer co-extruded film of a high density polyethylene layer, a medium density polyethylene layer and a high density polyethylene layer from the outside. By adopting such a configuration, the stretchability of the resin film can be further improved, the strength and heat resistance of the laminate of the present invention can be further improved, and curling of the substrate can be prevented. 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 further 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 resin film can be further improved.

[0034] For example, the film may be configured as a five-layer co-extruded film consisting of, from the outside, 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 (in this paragraph, for the sake of simplicity, these will be collectively referred to as low-density polyethylene layers), 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, improve the strength and heat resistance of the laminate of the present invention, and 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, and 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. The thickness of the high-density polyethylene layer is preferably the same as or greater than the thickness of the low-density polyethylene layer. The ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene 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 low-density polyethylene layer to 1 / 0.25 or more, heat resistance can be improved, and by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer to 1 / 1 or less, adhesion between the medium-density polyethylene layers can be 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 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 from the outside 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 in the manufacturing process can be significantly reduced, and ultimately production efficiency can be improved. Furthermore, stretching can also be carried out in the inflation film-forming machine, which can further improve production efficiency.

[0035] The polyethylenes with different densities and branching 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 stage or in two or more stages by any of gas phase polymerization, slurry polymerization, solution polymerization, and high pressure ionic polymerization.

[0036] 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 non-metallocene transition metal compound with an activating co-catalyst. Single-site catalysts are preferred because they have a more uniform active site structure than multi-site catalysts, making it possible to polymerize polymers with high molecular weights and highly uniform structures. Metallocene catalysts are particularly preferred as single-site catalysts. Metallocene catalysts are catalysts containing the following catalytic components: a transition metal compound of Group IV of the periodic table containing a ligand with a cyclopentadienyl skeleton, a co-catalyst, and optionally an organometallic compound and a carrier.

[0037] In the above-mentioned transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the cyclopentadienyl skeleton may be a cyclopentadienyl group, a substituted cyclopentadienyl group, or the like. 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, and halosilyl groups. 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.

[0038] In the transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the transition metal can be zirconium, titanium, hafnium, etc., with zirconium and hafnium being particularly preferred. The transition metal compound typically contains two ligands having a cyclopentadienyl skeleton, and the cyclopentadienyl ligands are preferably bonded to each other via 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. Substituted silylene groups are preferred. The above-mentioned transition metal compounds of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton can be used as a catalyst component, either singly or in combination.

[0039] 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 that 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 a cation with or without an active hydrogen group and a non-coordinating anion, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing a fluoro group.

[0040] The transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be supported on an inorganic or organic support. The support is preferably a porous oxide of an inorganic or organic compound, and specific examples include ion-exchange layered silicates such as montmorillonite, SiO2, Al2O3, MgO, ZrO2, TiO2, BO3, CaO, ZnO, BaO, ThO2, and mixtures thereof. Furthermore, examples of organometallic compounds that may be used if necessary include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organoaluminum compounds are preferred.

[0041] Copolymers of ethylene and other monomers can also be used as long as the properties of the present invention are not impaired. Examples of ethylene copolymers include copolymers of ethylene and an α-olefin 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. Copolymers with vinyl acetate or acrylic esters can also be used as long as the properties of the present invention are not impaired.

[0042] Furthermore, in the present invention, biomass-derived ethylene may be used as a raw material for obtaining the above-mentioned high-density polyethylene, instead of ethylene obtained from fossil fuels. Such biomass-derived polyethylene is a carbon-neutral material, and therefore 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. Alternatively, commercially available biomass-derived polyethylene (e.g., Green PE commercially available from Braskem) may be used.

[0043] It is also possible to use polyethylene recycled through mechanical recycling, which generally involves crushing collected polyethylene film and washing it with an alkali to remove dirt and foreign matter from the film surface, and then drying it at high temperature and reduced pressure for a certain period of time to diffuse any contaminants remaining inside the film, thereby decontaminating it and removing the dirt from the polyethylene film and returning it to polyethylene.

[0044] The substrate may contain additives within the range that does not impair the properties of the present invention, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0045] The substrate is preferably subjected to a surface treatment, which can improve adhesion to adjacent layers. The surface treatment method 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. Alternatively, an anchor coating layer may be formed on the surface of the substrate using a conventionally known anchor coating agent.

[0046] 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.

[0047] The substrate can be produced by forming a polyethylene film by a T-die method, an inflation method or the like, and then stretching the film.

[0048] When the substrate is produced by the T-die method, the MFR of the polyethylene 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.

[0049] When the substrate is produced by an inflation method, the MFR of the polyethylene is preferably 0.5 g / 10 min or more and 5 g / 10 min or less. By adjusting the MFR of the polyethylene to 0.5 g / 10 min or more, the processability of the laminate of the present invention can be improved, and by adjusting the MFR of the polyethylene to 5 g / 10 min or less, the film formability can be improved.

[0050] The substrate is not limited to those prepared by the above method, and commercially available substrates may also be used.

[0051] <Adhesive layer> In the first embodiment, the laminate of the present invention has an adhesive layer between the substrate and the heat seal layer or the vapor-deposited film, and in the second embodiment, has an adhesive layer between the substrate and the intermediate layer, thereby improving the adhesion between these layers. In the second embodiment, a second adhesive layer is provided between the intermediate layer and the heat seal layer, and this may have the same structure as the adhesive layer.

[0052] The adhesive layer contains at least one adhesive, and the adhesive may be a one-component curing type, a two-component curing type, or a non-curing type. 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, and among these, two-component curing urethane adhesives can be 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.

[0053] Furthermore, when an adhesive layer is provided adjacent to the vapor-deposited film that is an aluminum vapor-deposited 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 with a vapor-deposited film is used as a packaging material, a bending load is applied to the laminate by a molding machine or the like, 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.

[0054] 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 the main skeleton.

[0055] As a specific example of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound, the PASLIM series sold by DIC Corporation can be used.

[0056] The resin composition may further contain a plate-like inorganic compound, a coupling agent, cyclodextrin and / or a derivative thereof, and the like.

[0057] As polyester polyols having two or more hydroxyl groups in one molecule as functional groups, for example, the following [Example 1] to [Example 3] can be used. [Example 1] Polyester polyol obtained by polycondensation of ortho-oriented polycarboxylic acid or its anhydride with polyhydric alcohol [Example 2] Polyester polyol with a glycerol skeleton [Example 3] Polyester polyol with isocyanuric ring Each polyester polyol will be described below.

[0058] The polyester polyol according to the first example is a polycondensate obtained by polycondensing a polycarboxylic acid component containing at least one or more of orthophthalic acid and its anhydride, and 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 the content of orthophthalic acid and its anhydride relative to the total polycarboxylic acid components is 70 to 100 mass % are preferred.

[0059] The polyester polyol according to the first example essentially contains orthophthalic acid and its anhydride as polycarboxylic acid components, but other polycarboxylic acid components may be copolymerized within a range that does not impair the effects of this embodiment. Specific 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; aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, anhydrides of these dicarboxylic acids, and ester-forming derivatives of these dicarboxylic acids; and polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids. Among these, succinic acid, 1,3-cyclopentanedicarboxylic acid, and isophthalic acid are preferred. Two or more of the above other polycarboxylic acids may be used.

[0060] As a polyester polyol according to a 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 H (hydrogen atom) or a group represented by the following general formula (2). [ka]

[0061] In formula (2), n represents an integer of 1 to 5, X represents an arylene group selected from the group consisting of 1,2-phenylene groups, 1,2-naphthylene groups, 2,3-naphthylene groups, 2,3-anthraquinonediyl groups, and 2,3-anthracenediyl groups, which may have a substituent, and Y represents an alkylene group having 2 to 6 carbon atoms. However, at least one of R1, R2, and R3 represents a group represented by general formula (2).

[0062] 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).

[0063] In addition, the compound may be a mixture of two or more of the following compounds: 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).

[0064] 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 substituent includes a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

[0065] 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 preferred, and an ethylene group is most preferred.

[0066] 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.

[0067] Examples of aromatic polycarboxylic acids or anhydrides in which a carboxylic acid is substituted at the ortho position include orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracenecarboxylic acid or anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring, such as a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, or a naphthyl group.

[0068] Examples of polyhydric alcohol components include alkylene diols 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.

[0069] The polyester polyol according to the third example is a polyester polyol having an isocyanuric ring represented by the following general formula (3). [ka] 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 of the general formula (4). [ka]

[0070] In 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 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 is a group represented by general formula (4).

[0071] In the general formula (3), the alkylene group represented by -(CH2)n1- may be linear or branched. Among these, n1 is preferably 2 or 3, and most preferably 2.

[0072] In the general formula (4), n2 represents an integer of 2 to 4, and n3 represents an integer of 1 to 5. X represents an arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group, which may have a substituent.

[0073] 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 substituent includes a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group. The substituent for X is preferably a hydroxyl group, a cyano group, a nitro group, an amino group, a phthalimido group, a carbamoyl group, an N-ethylcarbamoyl group, or a phenyl group, and most preferably a hydroxyl group, a phenoxy group, a cyano group, a nitro group, a phthalimido group, or a phenyl group.

[0074] 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 preferred, and an ethylene group is most preferred.

[0075] 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).

[0076] In addition, the compound may be a mixture of two or more of the following compounds: 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).

[0077] The polyester polyol having an isocyanuric ring represented by 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.

[0078] 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.

[0079] 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 on any carbon atom of the aromatic ring.

[0080] Examples of the substituent include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

[0081] 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, or 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 preferred because of their excellent oxygen barrier properties and adhesiveness.

[0082] The isocyanuric ring is highly polar and trifunctional, and can increase the polarity of the entire system and the crosslink density. From these perspectives, it is preferable that the adhesive resin contains 5% by mass or more of the isocyanuric ring based on the total solid content of the adhesive resin.

[0083] 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 addition reaction using a known isocyanate blocking agent by a known, conventional appropriate method. Among these, from the viewpoints of adhesiveness and retort resistance, polyisocyanate compounds having three or more isocyanate groups are preferred, and from the viewpoints of oxygen barrier property and water vapor barrier property, aromatic compounds are preferred.

[0084] 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 alkylene oxide adducts thereof, or high-molecular-weight active hydrogen compounds. Examples of low molecular weight active hydrogen compounds include ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, and metaxylylenediamine. Examples of high molecular weight active hydrogen compounds include polymeric active hydrogen compounds of various polyester resins, polyether polyols, and polyamides.

[0085] The phosphoric acid-modified compound is, for example, a compound represented by the following general formula (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, 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. [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, a phenyl group which may have a substituent, and an alkyl group having 1 to 4 carbon atoms and having a (meth)acryloyloxy group, n 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 when both x and y are 0.

[0086] More specific examples 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.

[0087] The content of the phosphoric acid-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 adjusting the content of the phosphate-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 phosphate-modified compound to 10% by mass or less, the adhesiveness of the adhesive layer can be improved.

[0088] The resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound may contain a plate-like inorganic compound, which can improve the adhesiveness of the adhesive layer and the flex load resistance of the laminate of the present invention. Examples of the plate-like inorganic compounds include kaolinite-serpentine group clay minerals (halloysite, kaolinite, endelite, dickite, nacrite, antigorite, chrysotile, etc.) and pyrophyllite-talc group (pyrophyllite, talc, keroli, etc.).

[0089] Examples of coupling agents include silane-based coupling agents, titanium-based coupling agents, and aluminum-based coupling agents represented by the following general formula (7). These coupling agents may be used alone or in combination of two or more. [ka]

[0090] Examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxytrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β( N-beta(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-beta(aminoethyl)γ-aminopropyltrimethoxysilane, N-beta(aminoethyl)γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-triethoxysilyl-N-(1,3-dimethylbutylidene).

[0091] 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 dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, diisostearoyl ethylene titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and dicumyl phenyl oxyacetate titanate.

[0092] 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.

[0093] The resin composition may contain cyclodextrin and / or a derivative thereof, which can improve the adhesiveness of the adhesive layer and further improve the flex load resistance of the laminate of the present invention. Specifically, for example, cyclodextrin, alkylated cyclodextrin, acetylated cyclodextrin, hydroxyalkylated cyclodextrin, and the like, 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. These cyclodextrins and / or their derivatives may hereinafter be collectively referred to as dextrin compounds.

[0094] From the viewpoint of compatibility and dispersibility in the resin composition, it is preferable to use a cyclodextrin derivative as the cyclodextrin compound.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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. Furthermore, 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-deposited 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.

[0099] The adhesive layer can be formed by applying the adhesive to a substrate or the like and drying it using a conventionally known method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, and transfer roll coating.

[0100] <Heat seal layer> The heat seal layer of the laminate of the present invention is characterized by being made of polyethylene, just like the base material described above. By using such a structure, it is possible to produce a packaging material or the like that has sufficient strength and heat resistance and is recyclable. However, the intermediate layer is formed from an unstretched polyethylene resin film or by melt extrusion of polyethylene.

[0101] From the viewpoint of heat sealing properties, 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 properties of the present invention. From the viewpoint of environmental load, biomass-derived polyethylene or recycled polyethylene is preferred.

[0102] The heat seal layer may contain the above-mentioned additives to the extent that the properties of the present invention are not impaired.

[0103] 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 follows: 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; and 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 heat-sealability.

[0104] The thickness of the heat seal layer is preferably changed appropriately depending on the weight of the contents to be filled in the packaging material made from the laminate of the present invention. For example, when producing a packaging bag 20 as shown in FIG. 4 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 leakage of the filled contents due to damage to 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.

[0105] Furthermore, for example, when producing a stand pouch 30 as shown in FIG. 5 to be filled with contents 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 contents from leaking due to damage to 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 hatched areas in Figures 4 and 5 are heat-sealed areas.

[0106] <Vapor deposition film> In a first embodiment, the laminate of the present invention includes a vapor-deposited film between the substrate and the adhesive layer or between the heat seal layer and the adhesive layer, thereby improving the gas barrier properties of the laminate, specifically the oxygen barrier properties and water vapor barrier properties.

[0107] Examples of the vapor-deposited film include vapor-deposited films 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.

[0108] The thickness of the vapor-deposited 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.

[0109] When the vapor-deposited film is an aluminum vapor-deposited film, its 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.

[0110] The vapor-deposited film can be formed using a conventionally known method, for example, physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0111] Also, 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 deposition chamber is 10 -2 ~10 -8 After oxygen is introduced, the pressure is preferably about 10 -1 ~10 -6 A pressure of about mbar is preferred. The amount of oxygen introduced varies depending on the size of the deposition machine. An inert gas such as argon gas, helium gas, or nitrogen gas may be used as a carrier gas for the oxygen introduced, provided that this does not cause any problems. The film transport speed can be about 10 to 800 m / min.

[0112] The surface of the deposited film is preferably subjected to the above-mentioned surface treatment, which can improve adhesion to adjacent layers.

[0113] <Middle class> In a second embodiment of the present invention, the laminate includes an intermediate layer, which is made of polyethylene, just like the base material and the heat-sealing layer. This configuration improves the strength and heat resistance of the packaging material, and also makes the packaging material recyclable.

[0114] The intermediate layer is made of a stretched polyethylene film to improve the strength and heat resistance of the packaging material. The stretched film may be a uniaxially stretched film or a biaxially stretched film.

[0115] 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. The strength and heat resistance of the laminate of the present invention can be improved by stretching the stretched film at a stretch ratio of 2 or more in the machine direction (MD). On the other hand, the upper limit of the stretch ratio in the machine direction (MD) of the stretched film is not particularly limited, but is preferably 10 or less from the viewpoint of the breaking limit of the stretched film.

[0116] The stretching ratio in the transverse direction (TD) 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 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 from the viewpoint of the breaking limit of the stretched film, it is preferably set to 10 times or less.

[0117] Of the polyethylenes contained in the intermediate layer, 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 multilayer structure, similar to the substrate.

[0118] The intermediate layer may contain the above-mentioned additives to the extent that the properties of the present invention are not impaired.

[0119] The thickness of the intermediate layer 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 intermediate layer 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 intermediate layer 50 μm or less, the processability of the laminate of the present invention can be improved.

[0120] The intermediate layer may be one produced by the T-die method or inflation method, or a commercially available one may be used.

[0121] <Application> The laminate of the present invention can be particularly suitably used as a packaging material. The packaging material is not particularly limited, and may be a packaging bag 20 as shown in Fig. 4, or a stand-up pouch 30 having a body 31 and a bottom 32 as shown in Fig. 5. In the stand-up 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.

[0122] The packaging bag can be produced by folding the laminate in half, overlapping it so that the heat seal layer of the laminate is on the inside, and heat sealing the ends. Alternatively, the packaging bag can be produced by overlapping two laminates with their heat-sealable layers facing each other and then heat-sealing the ends thereof.

[0123] A stand-up pouch can be produced by heat-sealing the laminate into a cylindrical shape with the heat-seal layer facing inward to form a body, then folding the laminate into a V-shape with the heat-seal layer facing inward, sandwiching one end of the body, and heat-sealing to form a bottom.

[0124] The heat sealing method is not particularly limited, and can be performed by any known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, or ultrasonic sealing.

[0125] The contents filled into the packaging material are not particularly limited, and may be liquid, powder, or gel. The contents may also be food or non-food. After filling the contents, the opening can be heat-sealed to form a package. [Example]

[0126] The present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples.

[0127] <Example 1-1> The medium-density polyethylene was formed into a film by inflation molding to obtain a polyethylene film having a thickness of 100 μm. This polyethylene film was stretched in the machine direction (MD) at a stretching ratio of 5 times to obtain a 20 μm thick substrate A. The haze value of substrate A was measured and found to be 6.5%.

[0128] An image was formed on one surface of the substrate A by flexographic printing using the above-mentioned water-based flexographic ink.

[0129] As a heat seal layer, the above unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared, and an aluminum vapor deposition film having a thickness of 20 nm was formed on one surface of the film by the PVD method.

[0130] The image-forming surface of the substrate A and the vapor-deposited surface of the heat seal layer were laminated together via the two-component curing urethane adhesive to obtain a laminate of the present invention. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. The proportion of polyethylene in the laminate thus obtained was 94% by mass.

[0131] <Example 1-2> The high-density polyethylene and the medium-density polyethylene were extruded by inflation molding to produce a polyethylene film consisting of a high-density polyethylene layer / a medium-density polyethylene layer / a high-density polyethylene layer. The high-density polyethylene layer had a thickness of 20 μm, and the medium-density polyethylene layer had a thickness of 60 μm. This polyethylene film was stretched in the machine direction (MD) at a stretching ratio of 5 times to obtain a substrate B having a total thickness of 20 μm, with the high-density polyethylene layer being 4 μm thick and the medium-density polyethylene layer being 12 μm thick. The haze value of substrate B was measured and found to be 8.9%.

[0132] An image was formed on one surface of the substrate B by flexographic printing using the above-mentioned water-based flexographic ink.

[0133] As a heat seal layer, the above unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared, and an aluminum vapor deposition film having a thickness of 20 nm was formed on one surface of the film by the PVD method.

[0134] The image-forming surface of the substrate B and the vapor-deposited surface of the heat seal layer were laminated together via the two-component curing urethane adhesive to obtain a laminate of the present invention. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. The proportion of polyethylene in the laminate thus obtained was 94% by mass.

[0135] <Examples 1-3> The medium-density polyethylene was formed into a film by inflation molding to obtain a polyethylene film having a thickness of 100 μm. This polyethylene film was stretched in the machine direction (MD) and the transverse direction (TD) at a stretching ratio of 2.24 to obtain a 20 μm thick substrate C. The haze value of substrate C was measured and found to be 5.1%.

[0136] An image was formed on one surface of the substrate C by flexographic printing using the above-mentioned water-based flexographic ink.

[0137] As a heat seal layer, the above unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared, and an aluminum vapor deposition film having a thickness of 20 nm was formed on one surface of the film by the PVD method.

[0138] The image-forming surface of the substrate C and the vapor-deposited film of the heat seal layer were laminated together via the two-component curing urethane adhesive to obtain a laminate of the present invention. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. The proportion of polyethylene in the laminate thus obtained was 94% by mass.

[0139] <Examples 1-4> A laminate of the present invention was produced in the same manner as in Example 1-1, except that in Example 1-1, the image-forming surface of the substrate C and the vapor-deposited surface of the heat-sealing layer were bonded together using a two-component curing adhesive (manufactured by DIC Corporation, PASLIM VM001 / VM102CP) containing an isocyanate compound and a phosphoric acid-modified compound.

[0140] <Comparative Example 1-1> The medium-density polyethylene was formed into a film by inflation molding to obtain a substrate e having a thickness of 20 μm. The haze value of the substrate a was measured and found to be 23.5%.

[0141] An image was formed on one surface of the substrate a by flexographic printing using the above-mentioned water-based flexographic ink.

[0142] As a heat seal layer, the above unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared, and an aluminum vapor deposition film having a thickness of 20 nm was formed on one surface of the film by the PVD method.

[0143] The image-forming surface of the substrate a and the vapor-deposited surface of the heat seal layer were laminated together via the two-component curing urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. The proportion of polyethylene in the laminate thus obtained was 94% by mass.

[0144] <Comparative Example 1-2> The high-density polyethylene and the medium-density polyethylene were formed into a film by inflation molding to prepare a substrate b consisting of a high-density polyethylene layer / medium-density polyethylene layer / high-density polyethylene layer. The high-density polyethylene layer had a thickness of 4 μm, and the medium-density polyethylene layer had a thickness of 12 μm. The haze value of substrate b was measured and found to be 28.8%.

[0145] An image was formed on one surface of the substrate b by flexographic printing using the above-mentioned water-based flexographic ink.

[0146] As a heat seal layer, the above unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared, and an aluminum vapor deposition film having a thickness of 20 nm was formed on one surface of the film by the PVD method.

[0147] The image-forming surface of the substrate b and the vapor-deposited surface of the heat seal layer were laminated together via the two-component curing urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. The proportion of polyethylene in the laminate thus obtained was 97% by mass.

[0148] <Comparative Example 1-3> A laminate was obtained in the same manner as in Example 1-1, except that a 12 μm-thick biaxially stretched polyester film (manufactured by Toyobo Co., Ltd., product name: E5100) was used as the substrate A. The proportion of polyethylene in the thus obtained laminate was 71 mass %.

[0149] <Example 2-1> The medium-density polyethylene was formed into a film by inflation molding to obtain a polyethylene film having a thickness of 100 μm. This polyethylene film was stretched in the machine direction (MD) at a stretching ratio of 5 times to obtain a 20 μm-thick substrate D. The haze value of substrate D was measured and found to be 6.5%.

[0150] An image was formed on one surface of the substrate D by flexographic printing using the above-mentioned water-based flexographic ink.

[0151] 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 machine direction (MD) at a stretch ratio of 5 to obtain a 20 μm thick intermediate layer A. Next, a 20 nm thick aluminum vapor-deposited film was formed on one surface of the intermediate layer A by PVD.

[0152] The image forming surface of the substrate D was laminated onto the vapor-deposited surface of the 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.

[0153] The above-mentioned unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared as a heat seal layer, and laminated to the non-vapor-deposited surface of the intermediate layer A via the above-mentioned two-component curing 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. The proportion of polyethylene in the laminate thus obtained was 92% by mass.

[0154] <Example 2-2> The high-density polyethylene and the medium-density polyethylene were extruded by inflation molding to produce a polyethylene film consisting of a high-density polyethylene layer / a medium-density polyethylene layer / a high-density polyethylene layer. The high-density polyethylene layer had a thickness of 20 μm, and the medium-density polyethylene layer had a thickness of 60 μm. This polyethylene film was stretched in the machine direction (MD) at a stretching ratio of 5 times to obtain a substrate E having a total thickness of 20 μm, with the high-density polyethylene layer being 4 μm thick and the medium-density polyethylene layer being 12 μm thick. The haze value of substrate E was measured and found to be 8.9%.

[0155] An image was formed on one surface of the substrate E by flexographic printing using the above-mentioned water-based flexographic ink.

[0156] The high-density polyethylene and the medium-density polyethylene were extruded by inflation molding to produce a polyethylene film consisting of a high-density polyethylene layer / a medium-density polyethylene layer / a high-density polyethylene layer. The high-density polyethylene layer had a thickness of 20 μm, and the medium-density polyethylene layer had a thickness of 60 μm. This polyethylene film was stretched in the machine direction (MD) at a stretching ratio of 5 times to obtain an intermediate layer B having a total thickness of 20 μm, with the high-density polyethylene layer being 4 μm thick and the medium-density polyethylene layer being 12 μm thick. Next, a 20 nm thick aluminum vapor-deposited film was formed on one surface of intermediate layer B by the PVD method.

[0157] The image forming surface of the substrate E was laminated via the two-component curing urethane adhesive onto the vapor-deposited surface of the intermediate layer B. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm.

[0158] The above-mentioned unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared as a heat seal layer, and laminated to the non-vapor-deposited surface of the intermediate layer B via the above-mentioned two-component curing 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. The proportion of polyethylene in the laminate thus obtained was 92% by mass.

[0159] <Example 2-3> The medium-density polyethylene was formed into a film by inflation molding to obtain a polyethylene film having a thickness of 100 μm. This polyethylene film was stretched in the machine direction (MD) and the transverse direction (TD) at a stretching ratio of 2.24 to obtain a 20 μm thick substrate F. The haze value of substrate F was measured and found to be 5.1%.

[0160] An image was formed on one surface of the substrate F by flexographic printing using the above-mentioned water-based flexographic ink.

[0161] The medium-density polyethylene was formed into a film by inflation molding to obtain a polyethylene film having a thickness of 100 μm. This polyethylene film was stretched in the machine direction (MD) and the transverse direction (TD) at a stretching ratio of 2.24 to obtain a 20 μm-thick intermediate layer C. Next, a 20 nm-thick aluminum vapor-deposited film was formed on one surface of the intermediate layer C by the PVD method.

[0162] The image forming surface of the substrate F was laminated via the two-component curing urethane adhesive onto the vapor-deposited surface of the intermediate layer C. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm.

[0163] The above-mentioned unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared as a heat seal layer, and laminated to the non-vapor-deposited surface of the intermediate layer C via the above-mentioned two-component curing 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. The proportion of polyethylene in the laminate thus obtained was 92% by mass.

[0164] <Example 2-4> In Example 2-1, the image-forming surface of the substrate D and the vapor-deposited surface of the intermediate layer A were bonded together using a two-component curing adhesive containing an isocyanate compound and a phosphoric acid-modified compound (manufactured by DIC Corporation, PASLIM VM001 / VM102CP). The laminate of the present invention was prepared in the same manner as in Example 4-1.

[0165] <Comparative Example 4-1> The medium-density polyethylene was formed into a film by inflation molding to obtain a 20 μm-thick substrate c. The haze value of substrate c was measured and found to be 23.5%.

[0166] An image was formed on one surface of the substrate c by flexographic printing using the above-mentioned water-based flexographic ink.

[0167] The medium-density polyethylene was formed into a film by inflation molding to obtain an intermediate layer a having a thickness of 20 μm, and then an aluminum vapor-deposited film having a thickness of 20 nm was formed on one surface of the intermediate layer a by PVD.

[0168] The image forming surface of the substrate c was laminated onto the vapor-deposited surface of the 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.

[0169] The above unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared as a heat seal layer, and laminated to the non-vapor-deposited surface of the intermediate layer a via the above two-component curing urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. The proportion of polyethylene in the laminate thus obtained was 92% by mass.

[0170] <Comparative Example 2-2> The high-density polyethylene and the medium-density polyethylene were formed into a film by inflation molding to prepare a substrate d consisting of a high-density polyethylene layer / medium-density polyethylene layer / high-density polyethylene layer. The high-density polyethylene layer had a thickness of 4 μm, and the medium-density polyethylene layer had a thickness of 12 μm. The haze value of substrate d was measured and found to be 23.5%.

[0171] An image was formed on one surface of the substrate d by flexographic printing using the above-mentioned water-based flexographic ink.

[0172] The high-density polyethylene and the medium-density polyethylene were formed into a film by inflation molding to prepare an intermediate layer b consisting of a high-density polyethylene layer / a medium-density polyethylene layer / a high-density polyethylene layer. The high-density polyethylene layer had a thickness of 4 μm, and the medium-density polyethylene layer had a thickness of 12 μm. Next, an aluminum vapor deposition film having a thickness of 20 nm was formed on one surface of the intermediate layer b by the PVD method.

[0173] The image forming surface of the substrate d was laminated onto the vapor-deposited surface of the intermediate layer b 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] The above unstretched linear low-density polyethylene film having a thickness of 40 μm was prepared as a heat seal layer, and laminated to the non-vapor-deposited surface of the intermediate layer b via the above two-component curing urethane adhesive to obtain a laminate. The thickness of the adhesive layer formed by the two-component curing urethane adhesive was 3.0 μm. The proportion of polyethylene in the laminate thus obtained was 92% by mass.

[0175] <Comparative Example 2-3> A laminate was obtained in the same manner as in Example 2-1, except that the substrate and intermediate layer were changed to a 12 μm thick biaxially stretched polyester film (product name: E5100, manufactured by Toyobo Co., Ltd.). The proportion of polyethylene in the thus obtained laminate was 56 mass%.

[0176] <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 Tables 1 and 2. (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 pieces measuring 80 mm long x 80 mm wide were prepared from each of the laminates obtained in Examples 2-1 to 2-4, Comparative Examples 2-1 to 2-2, Examples 2-1 to 2-4, and Comparative Examples 2-1 to 2-3. Two test pieces were placed together with the heat seal layers facing each other, and three sides were heat sealed at 140°C to prepare a packaging bag. The produced packaging materials were visually observed and evaluated based on the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2. (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 observed on the surface of the packaging material, and adhesion to the heat seal bar was observed, making it impossible to form a bag.

[0178] <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 and 2. (Evaluation criteria) ◯: 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.

[0179] <Rigidity evaluation> The laminates prepared in the above Examples and Comparative Examples were cut into 10 mm wide test pieces, and their stiffness 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 and 2.

[0180] <Strength test> The laminates prepared in the above Examples and Comparative Examples were measured for strength when pierced with a 0.5 mm diameter needle using a tensile tester (manufactured by Orientec Co., Ltd., product name: RTC-1310A). The piercing speed was set to 50 mm / min. The measurement results are summarized in Tables 1 and 2.

[0181] <Flexural load resistance test> First, the oxygen permeability and water vapor permeability of the laminates obtained in the above Examples and Comparative Examples were measured. Oxygen permeability was measured using OXTRAN2 / 20 manufactured by MOCON under conditions of 23°C and 90% RH, and 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 and comparative examples 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 (Tester Sangyo Co., Ltd., product name: BE1006BE). After the bending load, the oxygen permeability and water vapor permeability of the laminate were measured. Tables 1 and 2 show the oxygen permeability and water vapor permeability of the laminate before and after the flex load test.

[0182] [Table 1]

[0183] [Table 2] [Explanation of symbols]

[0184] 10: laminate, 11: substrate, 12: adhesive layer, 13: heat seal layer, 14: vapor deposition film, 15: intermediate layer, 16: second adhesive layer, 20: packaging bag, 30: stand-up pouch, 31: body portion, 32: bottom portion

Claims

1. comprising at least a base material, an adhesive layer, and a heat seal layer, The base material and the heat seal layer are made of polyethylene. The heat seal layer has a multilayer structure, A vapor-deposited film is provided between the heat seal layer and the adhesive layer. A laminate characterized in that the substrate is made of a stretched film.

2. comprising at least a base material, a first adhesive layer, an intermediate layer, a second adhesive layer, and a heat seal layer, The base material, the intermediate layer, and the heat seal layer are all made of polyethylene. The heat seal layer has a multilayer structure, A vapor-deposited film is provided between the heat seal layer and the second adhesive layer. A laminate characterized in that the substrate and the intermediate layer are made of stretched film.

3. The aforementioned vapor-deposited film is an aluminum vapor-deposited film. The laminate according to claim 1 or 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 comprises a medium-density polyethylene layer.

5. The laminate according to any one of claims 1 to 4, wherein the substrate is a three-layer co-pressed stretched film consisting of a high-density polyethylene layer, a medium-density polyethylene layer, and a high-density polyethylene layer.

6. The laminate according to any one of claims 1 to 5, wherein the polyethylene content in the entire laminate is 90% by mass or more.

7. A laminate according to any one of claims 1 to 6, used for packaging material applications.

8. A packaging material made using a laminate according to any one of claims 1 to 7.

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

10. It is a stand-up pouch, Made using the laminate described in any one of claims 1 to 7, A stand-up pouch characterized in that the thickness of the heat-seal layer is 50 μm or more and 200 μm or less.

Images