Laminate and packaging container

Abstract

To provide a laminate including a base material composed of polyethylene and a heat seal layer, capable of obtaining sufficient heat seal strength when heat sealing is performed at a low temperature, and capable of manufacturing a packaging container excellent in aroma retention of contents.SOLUTION: The laminate includes a substrate composed of polyethylene and a heat seal layer, wherein the heat seal layer includes a polyethylene layer (1) having a relative density of 0. 925g / cm3 or less and a barrier layer containing a gas barrier layer, and a surface layer on one side of the laminate is the polyethylene layer (1).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate and a packaging container. [Background technology]

[0002] Conventionally, resin films made of polyesters such as polyethylene terephthalate (hereinafter also referred to as "polyester films") have been used as base materials for packaging materials because they are inexpensive and have excellent mechanical properties, chemical stability, heat resistance, and transparency (see, for example, Patent Document 1).

[0003] The polyester film is laminated with, for example, a polyethylene film that functions as a heat-sealing layer. Packaging containers are produced using packaging materials made of the laminate obtained in this way. However, packaging containers comprising a polyester film and a polyethylene film are generally difficult to separate into the individual films. Therefore, such packaging containers are not suitable for recycling after use, and are not actively recycled at present.

[0004] In view of this situation, the production of mono-material packaging containers has been studied in order to improve the recyclability of packaging containers. For example, packaging materials have been studied that include a laminate comprising a stretched polyethylene film (hereinafter also referred to as "stretched polyethylene film") as a base material instead of a polyester film, and a polyethylene film made of the same resin material as a heat-seal layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-053223 Summary of the Invention [Problem to be solved by the invention]

[0006] When using a stretched polyethylene film as the base material of a packaging material instead of a heat-resistant film such as a polyester film, it is desirable to perform heat sealing at a low temperature in order to suppress thermal degradation of the base material during heat sealing. Conventionally, polyethylene films have been used as heat-sealing layers. However, conventional heat-sealing layers have not been able to achieve sufficient heat-sealing strength when heat-sealing at low temperatures. Furthermore, the present inventors have found that packaging containers equipped with polyethylene films as heat-sealing layers do not adequately retain the aroma of the contents filled in the packaging container.

[0007] The problem to be solved by the present disclosure is to provide a laminate comprising a base material made of polyethylene and a heat seal layer, which laminate has sufficient heat seal strength when heat sealed at low temperatures and can be used to produce a packaging container that has excellent aroma retention for the contents. [Means for solving the problem]

[0008] The laminate of the present disclosure includes a substrate made of polyethylene and a heat seal layer, and the heat seal layer has a density of 0.925 g / cm 3 The laminate comprises the following polyethylene resin layer (1) and a barrier resin layer containing a gas barrier resin, and the surface layer on one side of the laminate is the polyethylene resin layer (1). [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a laminate comprising a substrate made of polyethylene and a heat seal layer, which laminate has sufficient heat seal strength when heat sealed at low temperatures and can be used to produce a packaging container that has excellent aroma retention properties for the contents. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view of one embodiment of a laminate (packaging material) of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view of one embodiment of the laminate (packaging material) of the present disclosure. [Figure 3] FIG. 3 is a schematic cross-sectional view of one embodiment of the laminate (packaging material) of the present disclosure. [Figure 4] FIG. 4 is a perspective view of one embodiment of a standing pouch. [Figure 5] FIG. 5 is a perspective view of one embodiment of a standing pouch. DETAILED DESCRIPTION OF THE INVENTION

[0011] The laminate and the like of the present disclosure will be described in detail below.

[0012] [Laminate] The laminate of the present disclosure includes a substrate made of polyethylene and a heat seal layer. The heat seal layer has a density of 0.925 g / cm 3 The laminate comprises a polyethylene resin layer (1) and a barrier resin layer containing a gas barrier resin. Hereinafter, the polyethylene resin layer (1) will also be simply referred to as the "resin layer (1)." The surface layer on one side of the laminate is the resin layer (1).

[0013] In one embodiment, the heat seal layer further comprises a polyethylene resin layer (2) as a surface layer on the substrate side of the heat seal layer. Hereinafter, the polyethylene resin layer (2) may also be simply referred to as "resin layer (2)." In one embodiment, the resin layer (1) is a surface layer on one side of the heat seal layer, and the resin layer (2) is a surface layer on the other side of the heat seal layer. In one embodiment, when a packaging container is produced using a packaging material made of the laminate of the present disclosure, the resin layer (1) is a layer facing the contents to be contained in the packaging container.

[0014] As described above, in the laminate of the present disclosure, the substrate is made of polyethylene. By using a laminate having such a configuration, for example, a packaging container with excellent recyclability can be produced.

[0015] In the present disclosure, the expression "AAA composed of polyethylene" means that the main component of the AAA is polyethylene, but is not limited to a configuration in which the AAA is composed solely of polyethylene. The AAA may contain components other than polyethylene. Specifically, the polyethylene content in the AAA is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0016] For example, polyethylene includes high-density polyethylene and linear low-density polyethylene, which are classified as the same type of resin material, whereas polyethylene and polyester are not classified as the same type of resin material.

[0017] The polyethylene content in the entire laminate of the present disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. Since such a laminate uses polyethylene, which is the same type of resin material, it can be classified as a so-called mono-material material and can be suitably used, for example, for producing mono-material packaging containers.

[0018] FIG. 1 shows one embodiment of a laminate of the present disclosure. The laminate 1 comprises a heat seal layer 2, an optional adhesive layer 32, and a substrate 30, in this order in the thickness direction. The heat seal layer 2 comprises a resin layer (1) 10 and a barrier resin layer 11, in this order in the thickness direction. In one embodiment, the laminate 1 further comprises a printed layer (not shown) on the substrate 30. The printed layer is usually formed on the surface of the substrate 30 facing the heat seal layer 2.

[0019] One embodiment of the laminate of the present disclosure is shown in Figure 2. The laminate 1 shown in Figure 2 is the same as the laminate shown in Figure 1, except that the heat seal layer 2 includes a resin layer (1) 10, a barrier resin layer 11, and a resin layer (2) 12 in this order in the thickness direction.

[0020] One embodiment of the laminate of the present disclosure is shown in Figure 3. The laminate 1 shown in Figure 3 is the same as the laminate shown in Figure 1, except that the heat seal layer 2 includes a resin layer (1) 10, an adhesive resin layer 13, a barrier resin layer 11, an adhesive resin layer 13, and a resin layer (2) 12 in this order in the thickness direction.

[0021] In the present disclosure, polyethylene refers to a polymer in which the content of ethylene-derived structural units in all repeating structural units is 50 mol% or more. In this polymer, the content of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The content can be measured by NMR.

[0022] In the present disclosure, the polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and an ethylenically unsaturated monomer other than ethylene. Examples of the ethylenically unsaturated monomer other than ethylene include α-olefins having 2 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene; vinyl monomers, such as vinyl acetate and vinyl propionate; and (meth)acrylic acid esters, such as methyl (meth)acrylate and ethyl (meth)acrylate.

[0023] In the present disclosure, polyethylene preferably includes high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, and very low density polyethylene.

[0024] In the present disclosure, the density of the polyethylene is as follows: The density of the high density polyethylene is preferably 0.945 g / cm 3 The upper limit of the density of high density polyethylene is, for example, 0.965 g / cm 3 is. The density of the medium density polyethylene is preferably 0.930 g / cm 3 Exceeds 0.945g / cm 3 The following is the result.

[0025] The density of the low density polyethylene is preferably 0.900 g / cm 3 Exceeds 0.930g / cm 3 Low-density polyethylene is usually polyethylene obtained by polymerizing ethylene using a high-pressure polymerization method.

[0026] The density of the linear low density polyethylene is preferably 0.900 g / cm 3 Exceeds 0.930g / cm 3 Linear low-density polyethylene is typically obtained by polymerizing ethylene and a small amount of α-olefins using a low-pressure polymerization method (e.g., polymerization using a Ziegler-Natta catalyst or a metallocene catalyst).

[0027] The density of the ultra-low density polyethylene is preferably 0.900 g / cm 3 The lower limit of the density of the ultra-low density polyethylene is, for example, 0.860 g / cm 3 is. The density of polyethylene is measured in accordance with JIS K7112, particularly Method D (density gradient tube method, 23°C).

[0028] In the present disclosure, the melt flow rate (MFR) of the polyethylene is preferably 0.1 g / 10 min or more and 50 g / 10 min or less, more preferably 0.3 g / 10 min or more and 30 g / 10 min or less, even more preferably 0.5 g / 10 min or more and 10 g / 10 min or less, and particularly preferably 0.7 g / 10 min or more and 5.0 g / 10 min or less, from the viewpoints of film-forming properties and processability of the laminate. The MFR of the polyethylene is measured by Method A in accordance with JIS K7210 under conditions of a temperature of 190°C and a load of 2.16 kg.

[0029] In the present disclosure, from the viewpoint of a balance between heat resistance and heat sealability, the melting point (Tm) of the polyethylene is preferably 100° C. or higher and 140° C. or lower, more preferably 105° C. or higher and 130° C. or lower, and even more preferably 110° C. or higher and 125° C. or lower. Tm is obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121.

[0030] Polyethylenes with different densities or branches can be obtained by appropriately selecting a polymerization method. For example, it is preferable to use a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as a polymerization catalyst and carry out polymerization in one or more stages by any of gas phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization.

[0031] A 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 cocatalyst. Single-site catalysts are preferred because they have a more uniform structure of the active site than multi-site catalysts, making it possible to obtain polymers with high molecular weights and highly uniform structures.

[0032] The single-site catalyst is preferably a metallocene catalyst, which comprises a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a cocatalyst, an organometallic compound as needed, and a support as needed.

[0033] Examples of the transition metal in the transition metal compound include zirconium, titanium, and hafnium, with zirconium and hafnium being preferred.

[0034] The cyclopentadienyl skeleton in the transition metal compound is a cyclopentadienyl group or a substituted cyclopentadienyl group. The substituted cyclopentadienyl group has at least one substituent selected from, for example, a hydrocarbon group having from 1 to 30 carbon atoms, a silyl group, a silyl-substituted alkyl group, a silyl-substituted aryl group, a cyano group, a cyanoalkyl group, a cyanoaryl group, a halogen group, a haloalkyl group, and a halosilyl group. The substituted cyclopentadienyl group has one 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 ring formed by bonding the substituents to each other may further have a substituent.

[0035] The transition metal compound usually has two ligands having a cyclopentadienyl skeleton. The ligands having each cyclopentadienyl skeleton 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. Among these, substituted silylene groups are preferred.

[0036] The co-catalyst refers to a component that enables a transition metal compound of Group IV of the periodic table to function effectively as a polymerization catalyst or a component that balances the ionic charge in a catalytically activated state. Examples of the co-catalyst include benzene-soluble aluminoxanes or 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.

[0037] Examples of organometallic compounds that may be used as needed include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organoaluminum compounds are preferred.

[0038] The transition metal compound may be used by being supported on an inorganic or organic carrier, preferably a porous oxide of an inorganic or organic compound, such as montmorillonite or other ion-exchangeable layered silicates, SiO2, Al2O3, MgO, ZrO2, TiO2, BO3, CaO, ZnO, BaO, ThO2, or mixtures thereof.

[0039] As the polyethylene, biomass-derived polyethylene may be used. That is, biomass-derived ethylene may be used as a raw material for obtaining polyethylene instead of ethylene obtained from fossil fuels. Biomass-derived polyethylene is a carbon-neutral material, and therefore the environmental impact of laminates or packaging materials can be reduced. Biomass-derived polyethylene can be produced, for example, by the method described in JP 2013-177531 A. Commercially available biomass-derived polyethylene (for example, Green PE commercially available from Braskem) may also be used.

[0040] The polyethylene may be recycled mechanically or chemically. This reduces the environmental impact of laminates or packaging materials. Mechanical recycling generally involves crushing recovered polyethylene film, 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 disperse any contaminants remaining inside the film, decontaminating it, and returning it to polyethylene. Chemical recycling generally involves breaking down recovered polyethylene film to the monomer level and repolymerizing the monomer to obtain polyethylene. The above description of polyethylene is applicable to the polyethylene in the following description.

[0041] <Heat seal layer> The polyethylene content in the entire heat seal layer is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. With such a configuration, for example, the recyclability of packaging materials made of the laminate of the present disclosure can be improved.

[0042] From the viewpoint of heat sealing property, the heat seal layer is preferably an unstretched film. The unstretched film refers to a film that has not been subjected to a stretching treatment, for example, an extrusion-molded film that has not been subjected to a stretching treatment. Details of the stretching treatment will be described later in the description of the substrate.

[0043] In one embodiment, the number of heat seal layers is 2 to 7, for example, 3 to 7, or 3 to 5. In one embodiment, the number of heat seal layers is an odd number, for example, 3, 5, or 7. With such a configuration, for example, the symmetry of the laminated structure of the heat seal layer is increased, and curling in the heat seal layer can be suppressed.

[0044] In the present disclosure, the density of each layer may be measured in accordance with the above-mentioned JIS K7112, or may be calculated from the density of the components constituting the layer. For example, when one layer contains multiple components (n types; n is an integer of 2 or more) with different densities (e.g., polyethylene), the average density D calculated according to the following formula (f1) av may be the density of the layer.

[0045] D av = ΣW i ×D i …(f1) In formula (f1), Σ is W for i from 1 to n. i ×D i where n is an integer greater than or equal to 2, and W i denotes the mass fraction of the i-th component, and D i is the density of the i-th component (g / cm 3 ) is shown.

[0046] In one embodiment, the heat seal layer is a coextruded resin film, and each layer constituting the heat seal layer is a coextruded resin layer. The coextruded resin film can be produced by film formation using, for example, an inflation method or a T-die method.

[0047] The total thickness of the heat seal layer is preferably 10 μm or more and 300 μm or less, more preferably 15 μm or more and 250 μm or less. From the viewpoint of the strength and processability of the heat seal layer, it is preferable that the total thickness of the heat seal layer be appropriately changed depending on the mass of the contents to be contained in the packaging container described below.

[0048] For example, when the packaging container is a small pouch, the total thickness of the heat seal layer is preferably 20 μm or more and 60 μm or less, in which case, for example, 1 g or more and 200 g or less of contents can be well accommodated in the small pouch.

[0049] For example, when the packaging container is a stand-up pouch, the total thickness of the heat seal layer is preferably 40 μm or more and 200 μm or less, more preferably 60 μm or more and 150 μm or less. In this case, for example, contents of 50 g or more and 2000 g or less can be well accommodated in the stand-up pouch. The above heat seal layer is suitable as a heat seal layer for a stand-up pouch.

[0050] Each layer of the heat seal layer will be described below.

[0051] (Resin layer (1)) The resin layer (1) contains one or more polyethylenes. The details of the polyethylene are as described above. The content of polyethylene in the resin layer (1) is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. With such a constitution, for example, the recyclability of the laminate can be improved.

[0052] The density of the resin layer (1) is 0.925 g / cm 3or less, preferably 0.860 g / cm 3 More than 0.924g / cm 3 or less, more preferably 0.900 g / cm 3 More than 0.923g / cm 3 or less, more preferably 0.900 g / cm 3 More than 0.922g / cm 3 The following is the result.

[0053] In one embodiment, when a packaging container is produced using a packaging material made of the laminate of the present disclosure, the resin layer (1) is a layer facing the content to be contained in the packaging container. 3 By ensuring that the temperature is not higher than 140°C, sufficient heat seal strength can be obtained even when heat sealing is performed at a low temperature (for example, about 140°C).

[0054] The resin layer (1) preferably contains linear low-density polyethylene. The linear low-density polyethylene is preferred so that the density of the resin layer (1) falls within the above range, and the density is 0.900 g / cm. 3 Exceeds 0.925g / cm 3 The following linear low density polyethylene is more preferred.

[0055] The content of the linear low-density polyethylene in the resin layer (1) is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. Such a constitution can improve, for example, the low-temperature heat sealability of the heat seal layer.

[0056] In one embodiment, the resin layer (1) contains low-density polyethylene, which can improve, for example, the film-forming properties and cuttability of the heat-sealable layer.

[0057] In one embodiment, the content of low-density polyethylene in the resin layer (1) is, for example, 0.5% by mass to 20% by mass, 1% by mass to 15% by mass, or 1.5% by mass to 10% by mass, which can improve, for example, the film-forming property and cuttability of the heat-sealable layer.

[0058] The resin layer (1) may contain one or more resin materials other than polyethylene. Examples of such resin materials include polyolefins such as polypropylene, (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins. From the viewpoint of the recyclability of the laminate, it is particularly preferable that the resin layer (1) does not contain any resin materials other than polyethylene.

[0059] In one embodiment, the resin layer (1) further contains an antiblocking agent, which can improve the antiblocking properties of the heat seal layer, for example.

[0060] Examples of antiblocking agents include inorganic antiblocking agents and organic antiblocking agents.

[0061] Examples of inorganic antiblocking agents include oxides such as silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, and zinc oxide; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; carbonates such as magnesium carbonate and calcium carbonate; sulfates such as calcium sulfate and barium sulfate; silicates such as magnesium silicate, aluminum silicate, calcium silicate, and aluminosilicate; kaolin, talc, zeolite (synthetic zeolite or natural zeolite), and diatomaceous earth.

[0062] Examples of organic antiblocking agents include (meth)acrylic resin particles such as polymethyl methacrylate (PMMA) resin particles, styrene resin particles, and melamine resin particles.

[0063] The antiblocking agent has an average particle size of, for example, 1 μm to 10 μm, which is a number-average particle size measured using a laser diffraction particle size distribution analyzer (SALD-2000J, manufactured by Shimadzu Corporation) or an equivalent device.

[0064] When forming the resin layer (1), a masterbatch containing an antiblocking agent and polyethylene may be used. The content of the antiblocking agent in the masterbatch is preferably 1% by mass or more and 45% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and even more preferably 10% by mass or more and 35% by mass or less. Specific examples of polyethylene include those mentioned above. The preferred physical properties (density, melting point, MFR, etc.) that the polyethylene should satisfy are also as mentioned above.

[0065] The resin layer (1) can contain one or more antiblocking agents. In one embodiment, the content of the antiblocking agent in the resin layer (1) is, for example, 0.1% by mass to 15% by mass, or 0.2% by mass to 10% by mass, which can improve the antiblocking properties of the heat seal layer.

[0066] The resin layer (1) may contain one or more additives, such as a compatibilizer, a crosslinking agent, a slip agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, a dye, and a modifying resin.

[0067] By using a compatibilizer, when a packaging container including the laminate of the present disclosure is heated and melted for recycling, the gas barrier resin contained in the barrier resin layer and the polyethylene contained in the resin layer (1) etc. tend to be mixed uniformly, thereby making it possible to prevent deterioration in the physical properties (e.g., mechanical properties and optical properties) of the polyethylene obtained by recycling.

[0068] From the viewpoint of recyclability, the compatibilizer is preferably an acid-modified polyolefin, more preferably an unsaturated carboxylic acid-modified polyolefin, and even more preferably an unsaturated carboxylic acid-modified polyethylene. Examples of unsaturated carboxylic acids include maleic acid and fumaric acid, and acid anhydrides, esters, or metal salts of unsaturated carboxylic acids may also be used. Maleic anhydride-modified polyethylene is particularly preferred as the compatibilizer.

[0069] When a compatibilizer is used, the content of the compatibilizer in the entire heat seal layer is, for example, 5% by mass or more and 30% by mass or less. By making the content of the compatibilizer 5% by mass or more, for example, the above-mentioned effects can be further improved. By making the content of the compatibilizer 30% by mass or less, for example, the strength of the heat seal layer can be improved. In one embodiment, the compatibilizer is preferably contained in the polyethylene resin layer.

[0070] In the heat seal layer, the difference (D2-D1) between the density D2 of the resin layer (2) and the density D1 of the resin layer (1) is preferably 0.020 g / cm 3 or less, more preferably 0.015 g / cm 3 This configuration improves the symmetry of the laminated structure of the heat seal layer, and for example, it is possible to suppress the occurrence of curling in the heat seal layer.

[0071] The ratio of the thickness of the resin layer (1) to the total thickness of the heat seal layer is preferably 10% or more and 50% or less, more preferably 15% or more and 50% or less, and even more preferably 20% or more and 50% or less.

[0072] (Resin layer (2)) The resin layer (2) contains one or more polyethylenes. The details of the polyethylene are as described above. The content of polyethylene in the resin layer (2) is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. With such a constitution, for example, the recyclability of the laminate can be improved.

[0073] In one embodiment, the resin layer (2) contains linear low-density polyethylene.

[0074] The content of linear low-density polyethylene in the resin layer (2) is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less. This configuration can improve, for example, the manufacturability of the heat-sealable layer and the recyclability of the laminate.

[0075] In one embodiment, the resin layer (2) contains a linear low-density polyethylene and at least one selected from high-density polyethylene and medium-density polyethylene. The total content of the high-density polyethylene and medium-density polyethylene in the resin layer (2) is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less. This configuration can improve, for example, the rigidity of the heat-sealable layer.

[0076] The resin layer (2) may contain one or more resin materials other than polyethylene. Examples of such resin materials include polyolefins such as polypropylene, (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins. From the viewpoint of the recyclability of the laminate, it is particularly preferable that the resin layer (2) does not contain any resin materials other than polyethylene.

[0077] The resin layer (2) may contain one or more additives, such as a compatibilizer, a crosslinking agent, an antiblocking agent, a slip agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, a dye, and a modifying resin.

[0078] The density of the resin layer (2) is preferably 0.900 g / cm 3 Exceeds 0.950g / cm 3 or less, more preferably 0.905 g / cm 3 More than 0.945g / cm 3 or less, more preferably 0.910 g / cm 3 More than 0.940g / cm 3This configuration, for example, increases the symmetry of the density in the layer direction in the heat seal layer, and can suppress the occurrence of curl in the heat seal layer.

[0079] The ratio of the thickness of the resin layer (2) to the total thickness of the heat seal layer is preferably 10% or more and 50% or less, more preferably 15% or more and 50% or less, and even more preferably 20% or more and 50% or less.

[0080] The surface of the resin layer 2 may be subjected to a surface treatment, for example, physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using gases such as oxygen gas and nitrogen gas, and glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0081] (Barrier resin layer) The heat seal layer includes a barrier resin layer. The barrier resin layer contains a gas barrier resin. This configuration can improve, for example, the gas barrier properties (specifically, oxygen barrier properties and water vapor barrier properties) of the laminate or packaging material as well as aroma retention. Specifically, by including a barrier resin layer in the heat seal layer, for example, it is possible to prevent aroma components contained in the contents from permeating the packaging container and to prevent the aroma components from being adsorbed onto a polyethylene resin layer or the like located outside the barrier resin layer in the packaging container. Therefore, it is possible to prevent a decrease in aroma components in the contents in the packaging container. In one embodiment, the heat seal layer includes a barrier resin layer between the resin layer (1) and the resin layer (2).

[0082] Examples of gas barrier resins include polyamide, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyacrylonitrile, polyester, polyurethane, and polyvinylidene chloride. Among these, polyamide and ethylene-vinyl alcohol copolymer are preferred, and polyamide is more preferred, from the viewpoint of obtaining a packaging container with excellent aroma retention and gas barrier properties.

[0083] The barrier resin layer can contain one or more types of gas barrier resins. The content of the gas barrier resin in the barrier resin layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more.

[0084] Below, we will explain raw material monomers from which the structural units contained in polyamides can be derived, and then we will explain specific polyamides. Examples of raw material monomers include lactams, aminocarboxylic acids, diamines, and dicarboxylic acids. Polyamides can be obtained, for example, by ring-opening polymerization of lactams, polycondensation of aminocarboxylic acids, polycondensation of diamines and dicarboxylic acids, or combinations thereof.

[0085] Examples of lactams include γ-butyrolactam, δ-valerolactam, ε-caprolactam, enantholactam, undecane lactam, and dodecane lactam. Among these, ε-caprolactam, enantholactam, undecane lactam, and dodecane lactam are preferred. The number of carbon atoms in the lactam is, for example, 4 to 12.

[0086] Examples of aminocarboxylic acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Among these, 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid are preferred. The number of carbon atoms in the aminocarboxylic acid is, for example, 6 to 12.

[0087] Examples of diamines include aliphatic diamines such as aliphatic chain diamines and alicyclic diamines, and aromatic diamines. The aliphatic diamines have, for example, 2 to 20 carbon atoms, preferably 4 to 12 carbon atoms.

[0088] Examples of the aliphatic chain diamine include aliphatic linear diamines and aliphatic branched diamines, such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-pentanediamine, 2-methyl-1,8-octanediamine, and 2,2,4- / 2,4,4-trimethylhexamethylenediamine.

[0089] Examples of alicyclic diamines include 1,3- / 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, bis(3-methyl-4-aminocyclohexyl)methane, (3-methyl-4-aminocyclohexyl)propane, 1,3- / 1,4-bis(aminomethyl)cyclohexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine, norbornanedimethyleneamine, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane.

[0090] Among the aliphatic diamines, aliphatic chain diamines are preferred, aliphatic straight-chain diamines are more preferred, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, nonamethylenediamine, decamethylenediamine and dodecamethylenediamine are further preferred, and hexamethylenediamine is particularly preferred.

[0091] Examples of aromatic diamines include phenylenediamines such as p-phenylenediamine and m-phenylenediamine; xylylenediamines such as p-xylylenediamine and m-xylylenediamine; tolylenediamines such as 2,4-tolylenediamine and 2,6-tolylenediamine; diaminonaphthalenes such as 1,4-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene and 2,6-diaminonaphthalene; 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, and 4,4'-diamino-3,3',5,5'-tetramethyl diaminodiphenylmethane compounds such as diphenylmethane, 4,4'-diamino-3,3',5,5'-tetraethyldiphenylmethane, and 4,4'-diamino-3,3'-dimethyl-5,5'-diethyldiphenylmethane; and bis(aminophenyl)propane compounds such as 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(4-aminophenyl)propane, 2,2'-bis(4-amino-3-methylphenyl)propane, 2,2'-bis(4-amino-3-ethylphenyl)propane, 2,2'-bis(4-amino-3,5-dimethylphenyl)propane, 2,2'-bis(4-amino-3,5-diethylphenyl)propane, and 2,2'-bis(4-amino-3-methyl-5-ethylphenyl)propane.

[0092] Among aromatic diamines, xylylenediamine is preferred, p-xylylenediamine and m-xylylenediamine are more preferred, and m-xylylenediamine is even more preferred.

[0093] Examples of dicarboxylic acids include aliphatic dicarboxylic acids such as aliphatic chain dicarboxylic acids and alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. The aliphatic dicarboxylic acids have, for example, 2 to 20 carbon atoms, preferably 6 to 12 carbon atoms.

[0094] Examples of the aliphatic chain dicarboxylic acid include aliphatic linear dicarboxylic acids and aliphatic branched dicarboxylic acids, such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and eicosane dioic acid.

[0095] Alicyclic dicarboxylic acids include, for example, 1,3- / 1,4-cyclohexanedicarboxylic acid, dicyclohexanemethane-4,4'-dicarboxylic acid, and norbornanedicarboxylic acid.

[0096] Among the aliphatic dicarboxylic acids, aliphatic chain dicarboxylic acids are preferred, aliphatic straight-chain dicarboxylic acids are more preferred, adipic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid are further preferred, and adipic acid is particularly preferred.

[0097] Examples of aromatic dicarboxylic acids include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid; naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; and diphenylmethanedicarboxylic acids such as diphenylmethane-2,4-dicarboxylic acid, diphenylmethane-3,3'-dicarboxylic acid, diphenylmethane-3,4'-dicarboxylic acid, and diphenylmethane-4,4'-dicarboxylic acid.

[0098] Among the aromatic dicarboxylic acids, phthalic acid compounds are preferred, with isophthalic acid and terephthalic acid being more preferred.

[0099] Examples of polyamides include aliphatic polyamides and semi-aromatic polyamides. As the polyamide, aliphatic polyamides are preferred, and crystalline aliphatic polyamides are more preferred.

[0100] Examples of aliphatic polyamides include aliphatic homopolyamides and aliphatic copolyamides. Aliphatic homopolyamides may be polyamides composed of one lactam or one aminocarboxylic acid, or polyamides composed of a combination of one aliphatic diamine and one aliphatic dicarboxylic acid. In the present disclosure, the latter case is also classified as a homopolyamide. Aliphatic copolyamides may be polyamides composed of two or more monomers selected from lactams and aminocarboxylic acids, polyamides composed of a combination of lactams and / or aminocarboxylic acids with aliphatic diamines and aliphatic dicarboxylic acids, or polyamides composed of a combination of one or more aliphatic diamines with one or more aliphatic dicarboxylic acids (excluding the combination of one aliphatic diamine and one aliphatic dicarboxylic acid).

[0101] In the following examples, polyamide is also referred to as "PA." Specific examples of aliphatic homopolyamides include polycaprolactam (PA6), polyenantholactam (PA7), polyundecane lactam (PA11), polylauryllactam (PA12), polyhexamethylene adipamide (PA66), polytetramethylene dodecamide (PA412), polypentamethylene azelamide (PA59), polypentamethylene sebacamide (PA510), polypentamethylene dodecamide (PA512), polyhexamethylene azelamide (PA69), polyhexamethylene sebacamide (PA610), polyhexamethylene dodecamide (PA612), poly Examples include nonamethylene adipamide (PA96), polynonameethylene azelamide (PA99), polynonameethylene sebacamide (PA910), polynonameethylene dodecamide (PA912), polydecamethylene adipamide (PA106), polydecamethylene azelamide (PA109), polydecamethylene decamide (PA1010), polydecamethylene dodecamide (PA1012), polydodecamethylene adipamide (PA126), polydodecamethylene azelamide (PA129), polydodecamethylene sebacamide (PA1210), and polydodecamethylene dodecamide (PA1212).

[0102] Specific examples of aliphatic copolymer polyamides include caprolactam / hexamethylenediaminoadipic acid copolymer (PA6 / 66), caprolactam / hexamethylenediaminoazelaic acid copolymer (PA6 / 69), caprolactam / hexamethylenediaminosebacic acid copolymer (PA6 / 610), caprolactam / hexamethylenediaminoundecanoic acid copolymer (PA6 / 611), caprolactam / hexamethylenediaminododecanoic acid copolymer (PA6 / 612), caprolactam / amino Examples include undecanoic acid copolymer (PA6 / 11), caprolactam / lauryllactam copolymer (PA6 / 12), caprolactam / hexamethylenediaminoadipic acid / lauryllactam copolymer (PA6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymer (PA6 / 66 / 610), and caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymer (PA6 / 66 / 612).

[0103] The relative viscosity of the aliphatic polyamide is preferably 1.5 to 5.0, more preferably 2.0 to 5.0, and even more preferably 2.5 to 4.5. The relative viscosity of the aliphatic polyamide is measured at 25°C in accordance with JIS K6920 by dissolving 1 g of polyamide in 100 mL of 96% concentrated sulfuric acid.

[0104] The semi-aromatic polyamide is a polyamide having structural units derived from an aromatic diamine and structural units derived from an aliphatic dicarboxylic acid, or a polyamide having structural units derived from an aliphatic diamine and structural units derived from an aromatic dicarboxylic acid. Examples include polyamides composed of an aromatic diamine and an aliphatic dicarboxylic acid, and polyamides composed of an aliphatic diamine and an aromatic dicarboxylic acid.

[0105] In the polyamides composed of aromatic diamines and aliphatic dicarboxylic acids, the diamines do not all need to be aromatic diamines, and they may further contain structural units derived from aliphatic diamines.In the polyamides composed of aliphatic diamines and aromatic dicarboxylic acids, the dicarboxylic acids do not all need to be aromatic dicarboxylic acids, and they may further contain structural units derived from aliphatic dicarboxylic acids.These polyamides may further contain structural units derived from lactams and / or aminocarboxylic acids.

[0106] Specific examples of semi-aromatic polyamides include polyhexamethylene terephthalamide (PA6T), polyhexamethylene isophthalamide (PA6I), polynonamethylene terephthalamide (PA9T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (PA66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (PA66 / 6I), polyhexamethylene terephthalamide / polycaproamide copolymer (PA6T / 6), polyhexamethylene isophthalamide / polycaproamide copolymer (PA6I / 6), polyhexamethylene terephthalamide / polycaproamide copolymer (PA6I / 6), and polyhexamethylene terephthalamide / polycaproamide copolymer (PA6I / 6). Examples include lidodecaamide copolymer (PA6T / 12), polyhexamethylene isophthalamide / polyhexamethylene terephthalamide copolymer (PA6I / 6T), polyhexamethylene terephthalamide / poly(2-methylpentamethylene terephthalamide) copolymer (PA6T / M5T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (PA66 / 6T / 6I), polyhexamethylene adipamide / polycaproamide / polyhexamethylene isophthalamide copolymer (PA66 / 6 / 6I), and polymetaxylylene adipamide (PAMXD6).

[0107] The melt volume rate (MVR) of the semi-aromatic polyamide is preferably 5 cm 3 / 10 minutes or more 200cm 3 / 10 minutes or less, preferably 10cm 3 / 100cm for more than 10 minutes 3The MVR is measured in accordance with ISO 1133 at a temperature of 275°C and a load of 5 kg.

[0108] In one embodiment, the barrier resin layer contains an aliphatic polyamide as the polyamide. The content of the aliphatic polyamide in the barrier resin layer is preferably more than 50% by mass, more preferably 60% by mass or more, and even more preferably 70% by mass or more, for example, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more.

[0109] In one embodiment, the barrier resin layer contains a crystalline aliphatic polyamide. Examples of crystalline aliphatic polyamides include PA6, PA11, PA12, PA66, PA610, PA612, PA6 / 66, and PA6 / 66 / 12. The melting point (Tm) of the crystalline aliphatic polyamide is preferably 170°C or higher and 300°C or lower, more preferably 170°C or higher and 250°C or lower, even more preferably 170°C or higher and 230°C or lower, particularly preferably 170°C or higher and 220°C or lower, 180°C or higher and 215°C or lower, or 180°C or higher and 210°C or lower. In the present disclosure, Tm is measured by differential scanning calorimetry (DSC) in accordance with JIS K7121. If the Tm is low, for example, when polyethylene and polyamide are co-extruded to form a co-extruded resin film, the difference in melting points between the polyethylene and polyamide is small, thereby improving moldability.

[0110] The difference (Tm1-Tm2) between the melting point (Tm1) of the crystalline aliphatic polyamide contained in the barrier resin layer and the melting point (Tm2) of the polyethylene contained in the polyethylene resin layer (1) is preferably 90°C or less, more preferably 80°C or less, and even more preferably 75°C or less. This embodiment can improve the film-forming suitability, for example, when the heat-sealable layer is produced by co-extrusion. The lower limit of this difference is, for example, 30°C, 40°C, or 50°C.

[0111] The barrier resin layer may contain one or more resin materials other than the gas barrier resin, such as polyolefins such as polyethylene and polypropylene, vinyl resins, cellulose resins, and ionomer resins.

[0112] The barrier resin layer may contain one or more additives, such as crosslinking agents, antiblocking agents, slip agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, dyes, and modifying resins.

[0113] Examples of lubricants include hydrocarbon lubricants, fatty acid lubricants, fatty acid amide lubricants, ester lubricants, and metal soaps. The lubricant may be liquid or solid.

[0114] Examples of hydrocarbon lubricants include liquid paraffin, natural paraffin, polyethylene wax, and microcrystalline wax. Examples of fatty acid lubricants include stearic acid and lauric acid. Examples of fatty acid amide lubricants include stearic acid amide, palmitic acid amide, N-oleyl palmitic acid amide, behenic acid amide, erucic acid amide, arachidic acid amide, oleic acid amide, methylene bisstearamide, and ethylene bisstearamide. Examples of ester lubricants include butyl stearate, hydrogenated castor oil, ethylene glycol monostearate, and stearate monoglyceride. Examples of metal soaps include zinc stearate and calcium stearate.

[0115] The thickness of the barrier resin layer is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 40 μm or less, and even more preferably 3 μm or more and 30 μm or less, or 5 μm or more and 20 μm or less. With such a configuration, for example, the gas barrier properties and aroma retention of a packaging container including the laminate of the present disclosure can be improved, and when the laminate is used to produce a mono-material packaging material, the recyclability of the mono-material packaging material can be improved.

[0116] The heat seal layer may have two or more barrier resin layers.

[0117] The ratio of the thickness of the barrier resin layer to the total thickness of the heat seal layer is preferably 1% or more and 25% or less, more preferably 3% or more and 20% or less, and even more preferably 5% or more and 15% or less, and the upper limit of the ratio may be 10%. With such a configuration, for example, it is possible to improve the gas barrier properties and aroma retention of a packaging container including the laminate of the present disclosure, and also to improve the recyclability of a mono-material packaging material produced using the laminate.

[0118] <Adhesive resin layer> In one embodiment, the heat seal layer includes an adhesive resin layer between the polyethylene resin layer (1) and the barrier resin layer. In one embodiment, the heat seal layer includes an adhesive resin layer between the polyethylene resin layer (2) and the barrier resin layer. This can improve adhesion between the polyethylene resin layer and the barrier resin layer, for example.

[0119] The adhesive resin layer is composed of, for example, an adhesive resin. Examples of adhesive resins include polyolefins, modified polyolefins, vinyl resins, polyethers, silicone resins, epoxy resins, and phenolic resins. Examples of modified polyolefins include modified polyolefins, particularly acid-modified polyolefins. Examples of modified polyolefins include graft-modified polyolefins with unsaturated carboxylic acids such as maleic acid and fumaric acid, or their acid anhydrides, esters, or metal salts. Among adhesive resins, modified polyolefins are preferred, and modified polyethylene is more preferred, from the viewpoint of obtaining a structure suitable for monomaterial packaging materials.

[0120] From the viewpoint of film-forming properties and processability, the melt flow rate (MFR) of the modified polyolefin is preferably 0.1 g / 10 min or more and 50 g / 10 min or less, more preferably 0.3 g / 10 min or more and 30 g / 10 min or less, even more preferably 0.5 g / 10 min or more and 10 g / 10 min or less, and particularly preferably 0.5 g / 10 min or more and 5.0 g / 10 min or less.

[0121] The adhesive resin layer can contain one or more adhesive resins. The thickness of the adhesive resin layer is, for example, 1 μm or more and 15 μm or less. <Middle class> The heat seal layer may further include an intermediate layer containing polyethylene between the resin layer (1) and the resin layer (2). The number of intermediate layers may be one, two or more, for example, three or more and five or less.

[0122] The intermediate layer may contain one or more polyethylenes. The details of the polyethylene are as described above. The content of polyethylene in the intermediate layer is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. With such a configuration, for example, the recyclability of the laminate can be improved.

[0123] Because the laminate of the present disclosure has the effects described above, it can be suitably used as a packaging material for producing stand-up pouches, and in particular, it can be suitably used as a packaging material for producing monomaterial stand-up pouches.

[0124] <Metal deposition film> In one embodiment, the laminate of the present disclosure includes a metal vapor-deposited film provided on a heat seal layer. The metal vapor-deposited film is provided, for example, on the surface of the resin layer (2) opposite to the surface on which the resin layer (1) is provided. In the following description, the heat seal layer on which the metal vapor-deposited film is formed is also referred to as a "vapor-deposited heat seal layer." This configuration can, for example, impart an excellent gloss to the packaging material and improve the gas barrier properties, specifically the oxygen barrier properties and water vapor barrier properties, of the packaging material. Furthermore, the provision of the metal vapor-deposited film can improve the light-blocking properties and aroma retention properties of the packaging material.

[0125] The metal vapor deposition film is made of metal such as aluminum, chromium, tin, nickel, copper, silver, gold, platinum, etc. Among these, aluminum vapor deposition film is preferred.

[0126] The thickness of the metal vapor deposition 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 metal vapor deposition film 1 nm or more, for example, it is possible to improve the metallic luster, light-blocking properties, and aroma retention of the packaging material. By making the thickness of the metal vapor deposition film 150 nm or less, for example, it is possible to suppress the occurrence of cracks in the metal vapor deposition film and improve the recyclability of the packaging material. The method for forming the metal vapor deposition film will be described in detail later.

[0127] The surface of the metal vapor-deposited film may be subjected to the above-mentioned surface treatment, which can improve the adhesion between the metal vapor-deposited film and a layer adjacent to the metal vapor-deposited film, for example.

[0128] <Base material> The substrate is made of polyethylene. Because the resin material constituting the substrate is polyethylene, which is the same type of resin material as the resin material constituting the heat seal layer, the laminate having such a configuration can be suitably used as a laminate for producing a mono-material packaging container.

[0129] Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene. From the viewpoint of the strength and heat resistance of the substrate, high-density polyethylene and medium-density polyethylene are preferred, and from the viewpoint of stretchability, medium-density polyethylene is preferred.

[0130] The substrate may contain one or more polyethylenes. The details of the polyethylene are as described above. The content of polyethylene in the substrate is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. With such a configuration, for example, the recyclability of the laminate can be improved.

[0131] The polyethylene content in each layer constituting the substrate is independently preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. Such a configuration can, for example, improve the recyclability of the laminate.

[0132] The substrate may contain one or more resin materials other than polyethylene. Examples of such resin materials include polyolefins such as polypropylene, (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins. From the viewpoint of recyclability, it is particularly preferable that the substrate does not contain any resin materials other than polyethylene.

[0133] The substrate may contain one or more additives. Examples of additives include crosslinking agents, antiblocking agents, slip agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, dyes, and modifying resins. When the substrate is a multilayer substrate as described below, each layer constituting the multilayer substrate can independently contain the above-mentioned additives.

[0134] At least one layer selected from the layers constituting the multilayer substrate may contain a slip agent. This can improve the processability of the multilayer substrate, for example. For example, in the stretched multilayer substrate of the fifth embodiment described below, the third layer may contain a slip agent, or all of the first to fifth layers may contain a slip agent.

[0135] Examples of slip agents include amide-based lubricants, fatty acid esters such as glycerin fatty acid esters, hydrocarbon waxes, higher fatty acid waxes, metal soaps, hydrophilic silicones, silicone-modified (meth)acrylic resins, silicone-modified epoxy resins, silicone-modified polyethers, silicone-modified polyesters, block-type silicone (meth)acrylic copolymers, polyglycerol-modified silicones, and paraffins. Among these, amide-based lubricants are preferred. Examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Among these, unsaturated fatty acid amides are preferred, and erucic acid amide is more preferred.

[0136] In the multilayer substrate, the slip agent content in the layer containing the slip agent may be, for example, 0.01% by mass to 3% by mass, or 0.03% by mass to 1% by mass, which can further improve the processability of the multilayer substrate.

[0137] The substrate may have a single-layer structure or a multi-layer structure. Hereinafter, a substrate having a multi-layer structure will also be referred to as a "multi-layer substrate." A multi-layer substrate is preferred from the viewpoint of improving its strength, heat resistance, and stretchability.

[0138] In the multilayer substrate, the density of the polyethylene constituting each layer may be the same or different. For example, the multilayer substrate may have a density gradient between the layers. By providing a density gradient in the multilayer substrate, for example, its strength, heat resistance, and stretchability can be improved.

[0139] In a multilayer substrate having a density gradient, the absolute value of the density difference between any two adjacent layers is preferably small. The absolute value of the density difference is preferably 0.040 g / cm 3 or less, more preferably 0.030 g / cm 3 or less, more preferably 0.020 g / cm 3 This configuration makes it possible to effectively prevent, for example, delamination at the interfaces between the layers.

[0140] The substrate is preferably subjected to a stretching treatment, and hereinafter such a substrate is also referred to as a "stretched substrate." The substrate is more preferably a multilayer substrate that has been subjected to a stretching treatment. Hereinafter such a substrate is also referred to as a "stretched multilayer substrate." The stretching treatment can improve, for example, the heat resistance and strength of the substrate. Such a stretched substrate, particularly a stretched multilayer substrate, can satisfy the physical properties required, for example, as the outer layer of a packaging material.

[0141] The stretching may be uniaxial or biaxial. In one embodiment, the stretching ratio in the longitudinal direction (MD) of the stretched substrate is preferably 2 to 10 times, more preferably 3 to 7 times. In one embodiment, the stretching ratio in the transverse direction (TD) of the stretched substrate is preferably 2 to 10 times, more preferably 3 to 7 times.

[0142] A stretching ratio of 2 times or more can improve, for example, the rigidity, strength, and heat resistance of the substrate, improve the printability of the substrate, and improve the transparency of the substrate.A stretching ratio of 10 times or less can achieve good stretching without causing breakage of the film, for example.

[0143] In one embodiment, the stretched substrate is a uniaxially stretched film, more specifically, a uniaxially stretched film that has been stretched in the machine direction (MD).

[0144] The stretched multilayer substrate has a multilayer structure of two or more layers. In one embodiment, the number of layers in the stretched multilayer substrate is from 2 to 7, for example, from 3 to 7, or from 3 to 5. The number of layers in the stretched multilayer substrate is preferably an odd number, for example, 3, 5, or 7. The multilayer structure of the stretched multilayer substrate can improve the balance between rigidity, strength, heat resistance, printability, and stretchability of the substrate. Each layer of the stretched multilayer substrate is preferably composed of polyethylene.

[0145] The difference (D3-D1) between the density D3 of the surface resin layer on the heat seal layer side of the stretched multilayer substrate and the density D1 of the resin layer (1) in the heat seal layer is, for example, 0.020 g / cm 3 More than 0.025g / cm 3 or more, or 0.030 g / cm 3 That's all.

[0146] The haze value of a substrate such as a stretched multilayer substrate is preferably 25% or less, more preferably 15% or less, and even more preferably 10% or less. The smaller the haze value, the better, but in one embodiment, the lower limit may be 0.1% or 1%. The haze value of the substrate is measured in accordance with JIS K7136.

[0147] The thickness of the substrate, such as a stretched multilayer substrate, is preferably 10 μm or more and 60 μm or less, more preferably 15 μm or more and 50 μm or less. When the thickness of the substrate is 10 μm or more, the rigidity and strength of the laminate can be improved. When the thickness of the substrate is 60 μm or less, the processability of the laminate can be improved. Within the range in which the above-mentioned effects can be obtained, a small thickness of the multilayer substrate is preferred, for example, from the viewpoint of cost reduction.

[0148] The substrate, such as a stretched multilayer substrate, may be subjected to the above-mentioned surface treatment. This can, for example, improve the adhesion between the substrate and a layer laminated on the substrate. An anchor coating layer may be formed on the surface of the substrate, such as a stretched multilayer substrate, using a conventionally known anchor coating agent.

[0149] A stretched multilayer substrate can be produced by forming a laminate from multiple resin materials or resin compositions using, for example, an inflation method or a T-die method, and then stretching the resulting laminate. The stretching treatment can improve the transparency, rigidity, strength, and heat resistance of the substrate, making it suitable for use as, for example, a substrate for packaging materials.

[0150] In one embodiment, the stretched multilayer substrate is obtained by stretching a laminate (precursor) having a multilayer structure. Specifically, the resin materials constituting each layer are co-extruded into a tubular shape to form a film, thereby producing a laminate. Alternatively, the resin materials constituting each layer are co-extruded into a tubular shape, and then the opposing layers are pressure-bonded together using a rubber roll or the like to produce a laminate. By producing a laminate using such a method, the number of defective products can be significantly reduced, and production efficiency can be improved.

[0151] For example, when the stretched multi-layer substrate is made of polyethylene and is produced by the T-die method, the melt flow rate (MFR) of the polyethylene constituting each layer of the multi-layer substrate is preferably 3 g / 10 min or more and 20 g / 10 min or less, from the viewpoints of film-forming properties and processability of the multi-layer substrate.

[0152] For example, when the stretched multi-layer substrate is made of polyethylene and is produced by an inflation method, the MFR of the polyethylene constituting each layer of the multi-layer substrate is preferably 0.2 g / 10 min or more and 5 g / 10 min or less, from the viewpoints of film-forming properties and processability of the multi-layer substrate.

[0153] The stretched multilayer substrate can be obtained, for example, by stretching the above-mentioned laminate. The preferred stretching ratio is as described above. Note that the laminate can also be stretched in an inflation film-forming machine. This allows the production of a stretched multilayer substrate, thereby further improving production efficiency.

[0154] Hereinafter, several examples of embodiments of the stretched multilayer base material will be described. Hereinafter, a layer having a polyethylene content of 80% by mass or more will be referred to as a "polyethylene layer." For example, a layer having a high-density polyethylene content of 80% by mass or more will be referred to as a "high-density polyethylene layer."

[0155] The stretched multilayer substrate of the first embodiment includes, in the thickness direction, a medium-density polyethylene layer, a high-density polyethylene layer, a blend layer of medium-density polyethylene and high-density polyethylene, a high-density polyethylene layer, and a medium-density polyethylene layer, in this order. This configuration can improve, for example, the printability, strength, and heat resistance of the substrate, and the stretchability of the pre-stretched laminate.

[0156] In the blend layer of medium-density polyethylene and high-density polyethylene, the mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) is preferably 0.25 or more and 4 or less, more preferably 0.4 or more and 2.4 or less.

[0157] The stretched multilayer substrate of the second embodiment includes, in the thickness direction, a medium-density polyethylene layer, a medium-density polyethylene layer, a blend layer of medium-density polyethylene and linear low-density polyethylene, a medium-density polyethylene layer, and another medium-density polyethylene layer, in this order. This configuration can improve, for example, the printability, strength, and heat resistance of the substrate, and the stretchability of the pre-stretched laminate.

[0158] In the blend layer of medium-density polyethylene and linear low-density polyethylene, the mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) is preferably 0.25 or more and 4 or less, more preferably 0.4 or more and 2.4 or less.

[0159] The stretched multilayer substrate of the third embodiment includes, in the thickness direction, a blend layer of medium-density polyethylene and high-density polyethylene, a blend layer of medium-density polyethylene and linear low-density polyethylene, a linear low-density polyethylene layer, a blend layer of medium-density polyethylene and linear low-density polyethylene, and a blend layer of medium-density polyethylene and high-density polyethylene. This configuration can improve, for example, the printability, strength, and heat resistance of the substrate, and the stretchability of the pre-stretched laminate.

[0160] In the blend layers of medium-density polyethylene and high-density polyethylene, the mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) is preferably 0.25 or more and 4 or less, more preferably 0.4 or more and 2.4 or less.

[0161] In the blend layer of medium-density polyethylene and linear low-density polyethylene, the mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) is preferably 0.25 or more and 4 or less, more preferably 0.4 or more and 2.4 or less.

[0162] The stretched multilayer substrate of the fourth embodiment includes, in the thickness direction, a blend layer of high-density polyethylene and medium-density polyethylene, a medium-density polyethylene layer, a blend layer of linear low-density polyethylene and medium-density polyethylene, a medium-density polyethylene layer, and a blend layer of high-density polyethylene and medium-density polyethylene. This configuration can improve, for example, the printability, strength, and heat resistance of the substrate, and the stretchability of the pre-stretched laminate.

[0163] In the blend layers of high-density polyethylene and medium-density polyethylene, the mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) is preferably 0.25 or more and 4 or less, more preferably 0.4 or more and 2.4 or less.

[0164] In the blend layer of linear low-density polyethylene and medium-density polyethylene, the mass ratio of linear low-density polyethylene to medium-density polyethylene (linear low-density polyethylene / medium-density polyethylene) is preferably 0.25 or more and 4 or less, more preferably 0.4 or more and 2.4 or less.

[0165] The stretched multilayer substrate of the fifth embodiment comprises, in the thickness direction, a first layer containing medium-density polyethylene and high-density polyethylene, a second layer containing high-density polyethylene, a third layer containing linear low-density polyethylene, a fourth layer containing high-density polyethylene, and a fifth layer containing medium-density polyethylene and high-density polyethylene, in this order.

[0166] When printing an image on a substrate, the substrate may be subjected to a surface treatment such as corona discharge treatment as a pretreatment. A layer containing medium-density polyethylene tends to have higher durability against the surface treatment than a layer containing only high-density polyethylene as the polyethylene. Therefore, the layer containing medium-density polyethylene has excellent ink adhesion during printing after the surface treatment. Furthermore, a layer containing medium-density polyethylene and high-density polyethylene also has the heat resistance required during printing and heat sealing. Furthermore, a layer containing medium-density polyethylene contributes to improving the stretchability of a laminate, which is a precursor to a multilayer substrate.

[0167] The mass ratio of the medium-density polyethylene to the high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the first layer and the fifth layer is preferably 1.1 or more and 5 or less, more preferably 1.5 or more and 3 or less, thereby further improving the balance between ink adhesion and heat resistance.

[0168] The total content of the medium-density polyethylene and the high-density polyethylene in the first layer and the fifth layer is independently preferably at least 80% by mass, more preferably at least 90% by mass, and even more preferably at least 95% by mass, thereby further improving the ink adhesion and heat resistance of the substrate.

[0169] The second and fourth layers each contribute to improving the heat resistance of the substrate. That is, by incorporating high-density polyethylene into the second and fourth layers in addition to the first and fifth layers, the heat resistance of the substrate can be further improved.

[0170] The second layer and the fourth layer may each independently further contain low-density polyethylene, which can further improve the balance of heat resistance, rigidity, and processability of the substrate.

[0171] The mass ratio of high-density polyethylene to low-density polyethylene (high-density polyethylene / low-density polyethylene) in the second layer and the fourth layer is independently preferably from 1 to 4, more preferably from 1.5 to 3. This allows the substrate to have a better balance of heat resistance, rigidity, and processability.

[0172] The content of high-density polyethylene in each of the second layer and the fourth layer is preferably more than 50% by mass, more preferably 55% by mass or more, and even more preferably 60% by mass or more, which can further improve the heat resistance of the substrate.

[0173] The total content of high-density polyethylene and low-density polyethylene in the second layer and the fourth layer is independently preferably at least 80% by mass, more preferably at least 90% by mass, and even more preferably at least 95% by mass, thereby further improving the balance between heat resistance, rigidity, and processability of the substrate.

[0174] The thickness of each of the second layer and the fourth layer is independently preferably 0.5 μm to 15 μm, more preferably 1 μm to 10 μm, and even more preferably 1 μm to 8 μm, which can further improve the heat resistance of the substrate.

[0175] The third layer contributes to improving the stretchability of the laminate, which is the precursor to the multi-layer substrate. The third layer may further contain low density polyethylene.

[0176] The content of the linear low-density polyethylene in the third layer is preferably more than 50% by mass, more preferably at least 60% by mass, even more preferably at least 70% by mass, and even more preferably at least 80%, at least 90%, or at least 95% by mass, thereby further improving the balance between heat resistance, rigidity, and extensibility.

[0177] When the third layer contains low-density polyethylene, the content of low-density polyethylene is preferably less than 50% by mass, more preferably 5% to 40% by mass, and even more preferably 10% to 30% by mass.

[0178] The thickness of the third layer is preferably from 1 μm to 50 μm, more preferably from 2 μm to 40 μm, and even more preferably from 5 μm to 30 μm, which can further improve the balance between heat resistance, rigidity, and stretchability.

[0179] The ratio of the total thickness of the second layer and the fourth layer to the thickness of the third layer (total thickness of the second layer and the fourth layer / thickness of the third layer) is preferably 0.1 to 10, more preferably 0.2 to 5, and even more preferably 0.5 to 2. This can further improve the rigidity, strength, and heat resistance of the substrate.

[0180] In the stretched multilayer substrates of the first to fifth embodiments, the thickness of each of the two surface resin layers is preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 8 μm or less, and even more preferably 1 μm or more and 5 μm or less. This can further improve, for example, the heat resistance and printability of the substrate. In the case of the stretched multilayer substrate of the fifth embodiment, the two surface resin layers are the first layer and the fifth layer in one embodiment.

[0181] In the stretched multilayer substrates of the first to fifth embodiments, the thickness of each of the two surface resin layers is preferably smaller than the total thickness of the three inner layers (the multilayer intermediate layer). The ratio of the thickness of each of the two surface resin layers to the total thickness of the multilayer intermediate layer (surface resin layer / multilayer intermediate layer) is preferably 0.05 to 0.8, more preferably 0.1 to 0.7, and even more preferably 0.1 to 0.4. This can further improve, for example, the rigidity, strength, and heat resistance of the substrate. In the case of the stretched multilayer substrate of the fifth embodiment, the multilayer intermediate layer is the second to fourth layers in one embodiment.

[0182] The stretched multilayer substrate of the sixth embodiment comprises a high-density polyethylene layer and a medium-density polyethylene layer in this order in the thickness direction. The surface resin layer of the substrate is a high-density polyethylene layer, which can improve, for example, the strength and heat resistance of the substrate. The substrate comprises a medium-density polyethylene layer, which can improve, for example, the stretchability of the laminate before stretching.

[0183] The stretched multilayer substrate of the seventh embodiment includes a high-density polyethylene layer, a medium-density polyethylene layer, and a high-density polyethylene layer in this order in the thickness direction. This configuration can improve the strength and heat resistance of the substrate, suppress curling in the substrate, and improve the stretchability of the pre-stretched laminate, for example.

[0184] In the stretched multilayer substrates of the sixth and seventh embodiments, the thickness of the high-density polyethylene layer is preferably equal to or less than the thickness of the medium-density polyethylene layer, and the ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer is preferably 0.1 or more and 1 or less, more preferably 0.2 or more and 0.5 or less.

[0185] The stretched multilayer substrate of the eighth embodiment comprises, in this order in the thickness direction, 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 (for simplicity, these three layers are collectively referred to as the "low-density polyethylene layer, etc."), a medium-density polyethylene layer, and a high-density polyethylene layer. This configuration can, for example, improve the stretchability of the laminate before stretching, improve the strength and heat resistance of the substrate, and suppress curling in the substrate.

[0186] In the stretched multilayer substrate of the eighth embodiment, the thickness of the high-density polyethylene layer is preferably equal to or less than the thickness of the medium-density polyethylene layer, and the ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer is preferably 0.1 or more and 1 or less, more preferably 0.2 or more and 0.5 or less.

[0187] In the stretched multilayer substrate of the eighth embodiment, the thickness of the high-density polyethylene layer is preferably equal to or greater than the thickness of the low-density polyethylene layer, etc. The ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer, etc. is preferably 1 or more and 4 or less, more preferably 1 or more and 2 or less.

[0188] Other embodiments of the stretched multilayer substrate include a substrate comprising, in this order in the thickness direction, a high-density polyethylene layer, a high-density polyethylene layer, a blend layer of medium-density polyethylene and high-density polyethylene, a high-density polyethylene layer, and a high-density polyethylene; and a substrate comprising, in this order in the thickness direction, a medium-density polyethylene layer, a high-density polyethylene layer, a linear low-density polyethylene layer, a high-density polyethylene layer, and a medium-density polyethylene layer.

[0189] Further, a substrate may be provided with, in the thickness direction, a high-density polyethylene layer, a blend layer of high-density polyethylene and medium-density polyethylene, a low-density polyethylene layer or the like, a blend layer of high-density polyethylene and medium-density polyethylene, and a high-density polyethylene layer in this order.

[0190] <Barrier layer> In one embodiment, the laminate of the present disclosure includes a barrier layer between the substrate and the heat seal layer or the vapor-deposited heat seal layer, which can improve, for example, the gas barrier properties, specifically the oxygen barrier properties and water vapor barrier properties, of the laminate.

[0191] The barrier layer is formed, for example, on the surface of the substrate. Alternatively, a barrier layer may be provided between the substrate and the heat seal layer or vapor-deposited heat seal layer via an adhesive or the like. For example, a barrier film comprising a second substrate and a barrier layer formed on the second substrate may be provided between the substrate and the heat seal layer or vapor-deposited heat seal layer via an adhesive or the like. In this embodiment, from the viewpoint of recyclability, the second substrate in the barrier film is preferably made of polyethylene, which is the same type of resin material as the resin material constituting the substrate. The polyethylene content in the second substrate is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. This can improve the recyclability of the laminate.

[0192] In one embodiment, the barrier layer is a vapor-deposited film. Examples of vapor-deposited films include metals such as aluminum, chromium, tin, nickel, copper, silver, gold, and platinum; and inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide. Among these, aluminum vapor-deposited films, aluminum oxide (alumina) vapor-deposited films, and silicon oxide (silica) vapor-deposited films are preferred.

[0193] 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, for example, the oxygen barrier property and water vapor barrier property of the laminate can be further improved. By making the thickness of the vapor-deposited film 150 nm or less, for example, the occurrence of cracks in the vapor-deposited film can be suppressed and the recyclability of the laminate can be improved.

[0194] Examples of methods for forming a vapor-deposited film include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating; and chemical vapor deposition (CVD) methods such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. The vapor-deposited film may be a composite film containing two or more vapor-deposited films of different inorganic oxides, formed by combining both physical vapor deposition and chemical vapor deposition.

[0195] The vacuum level in the deposition chamber was 10 -2 ~10 -8 After oxygen is introduced, the pressure is preferably about 10 -1 ~10 -6 The pressure is preferably about 100 mbar. The amount of oxygen introduced varies depending on the size of the deposition machine. An inert gas such as argon, helium, or nitrogen may be used as a carrier gas for the oxygen introduced, provided that no problems occur. The transport speed of the target film on which the deposition film is formed is, for example, 10 m / min or more and 800 m / min or less.

[0196] The surface of the vapor-deposited film may be subjected to the above-mentioned surface treatment, which can improve the adhesion between the vapor-deposited film and a layer adjacent to the vapor-deposited film, for example.

[0197] For example, when the vapor-deposited film is composed of an inorganic oxide such as aluminum oxide or silicon oxide, a barrier coat layer may be provided on the surface of the vapor-deposited film. In this case, the barrier layer includes a vapor-deposited film and a barrier coat layer. In one embodiment, the laminate of the present disclosure includes a substrate, a vapor-deposited film, a barrier coat layer, and a heat seal layer or a vapor-deposited heat seal layer, in this order in the thickness direction. By adopting such a configuration, for example, the gas barrier properties of the laminate can be improved and the occurrence of cracks in the vapor-deposited film can be effectively suppressed.

[0198] In one embodiment, the barrier coat layer is made of a gas barrier resin, such as an ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyacrylonitrile, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide, polyurethane, and polyvinylidene chloride.

[0199] The content of the gas barrier resin in the barrier coat layer is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Such a configuration can improve, for example, the gas barrier properties of the barrier coat layer.

[0200] The thickness of the barrier coat layer is preferably 0.01 μm or more and 10 μm or less, more preferably 0.1 μm or more and 5 μm or less. By making the thickness of the barrier coat layer 0.01 μm or more, for example, the gas barrier property can be further improved.

[0201] The barrier coat layer can be formed, for example, by dissolving or dispersing a material such as a gas barrier resin in water or an appropriate organic solvent, applying the resulting coating liquid, and drying it.

[0202] In another embodiment, the barrier coat layer is a gas barrier coating layer formed by mixing an alkoxide, a water-soluble polymer, and optionally a silane coupling agent, and then adding water, an organic solvent, and a sol-gel catalyst to obtain a gas barrier composition, which is then coated on a vapor-deposited film and dried. The gas barrier coating layer contains a hydrolysis polycondensate obtained by hydrolyzing and polycondensing the alkoxide or the like by a sol-gel method. Each of the above components can be used alone or in combination of two or more.

[0203] The alkoxide is represented by, for example, formula (1). R 1 n M(OR 2 ) m (1) In formula (1), R 1 and R 2 each independently represents an organic group having 1 to 8 carbon atoms; M represents a metal atom; n represents an integer of 0 or more; m represents an integer of 1 or more; and n+m represents the valence of M.

[0204] R 1 and R 2 Examples of the organic group include alkyl groups having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-hexyl group, and an n-octyl group. The metal atom M is, for example, silicon, zirconium, titanium or aluminum.

[0205] Examples of the alkoxide represented by formula (1) include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0206] Examples of water-soluble polymers include polyvinyl alcohol and ethylene-vinyl alcohol copolymers. Depending on the desired physical properties, such as oxygen barrier property, water vapor barrier property, water resistance, and weather resistance, either polyvinyl alcohol or ethylene-vinyl alcohol copolymer may be used, or both may be used in combination. Alternatively, a gas barrier coating layer obtained using polyvinyl alcohol and a gas barrier coating layer obtained using an ethylene-vinyl alcohol copolymer may be laminated. The amount of water-soluble polymer used is preferably 5 to 500 parts by mass per 100 parts by mass of the alkoxide represented by formula (1).

[0207] As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used, and an organoalkoxysilane having an epoxy group is preferred, such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The amount of the silane coupling agent used is preferably 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the alkoxide represented by formula (1).

[0208] Examples of organic solvents that can be used in preparing the gas barrier composition include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, and n-butyl alcohol.

[0209] The sol-gel catalyst is preferably an acid or an amine compound. Examples of the acid include mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid; and organic acids such as acetic acid and tartaric acid. The amount of the acid used is preferably 0.001 mol or more and 0.05 mol or less per 1 mol of the total molar amount of the alkoxide represented by formula (1) and the silane coupling agent.

[0210] Examples of the amine compound include N,N-dimethylbenzylamine, tripropylamine, tributylamine, and tripentylamine. The amount of the amine compound used is preferably 0.01 to 1.0 parts by mass relative to 100 parts by mass of the total amount of the alkoxide represented by formula (1) and the silane coupling agent.

[0211] Examples of methods for applying the gas barrier composition include roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brush coating, bar coating, and applicator coating.

[0212] Hereinafter, one embodiment of the method for forming the gas barrier coating layer will be described. A gas barrier composition is prepared by mixing an alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and, if necessary, a silane coupling agent. A polycondensation reaction gradually progresses within the composition. The composition is applied to a vapor-deposited film by a conventional method and dried. This drying further promotes polycondensation of the alkoxide and the water-soluble polymer (and the silane coupling agent, if the composition contains one) to form a composite polymer layer. Multiple composite polymer layers may be laminated by repeating the above procedure. Finally, the composition is heated at a temperature of preferably 20°C to 250°C, more preferably 50°C to 220°C, for example, 50°C to 120°C, for 1 second to 10 minutes. This allows the formation of a gas barrier coating layer.

[0213] The thickness of the gas barrier coating layer formed from the gas barrier composition using an alkoxide is preferably 0.01 μm to 100 μm, more preferably 0.1 μm to 50 μm, which can improve the gas barrier properties and prevent cracks from occurring in the vapor-deposited film, for example.

[0214] <Print layer> In one embodiment, the laminate of the present disclosure further includes a printed layer formed on the above-described substrate. In one embodiment, the laminate of the present disclosure preferably includes a printed layer on the surface of the substrate facing the heat seal layer, since this can suppress deterioration of the image over time. When the laminate includes a barrier layer on the substrate, for example, a printed layer may be provided on the barrier layer. In this case, the laminate of the present disclosure includes, for example, a substrate, a barrier layer, a printed layer, and a heat seal layer or a vapor-deposited heat seal layer in this order in the thickness direction.

[0215] The printed layer includes, for example, an image. Examples of images include letters, figures, symbols, and combinations thereof. Examples of methods for forming the printed layer include gravure printing, offset printing, and flexographic printing. In one embodiment, flexographic printing is preferred from the viewpoint of reducing the environmental load. Furthermore, from the viewpoint of reducing the environmental load, the printed layer may be formed on the surface of the substrate using a biomass-derived ink.

[0216] <Adhesive layer> In one embodiment, the laminate of the present disclosure includes an adhesive layer between any layers, such as between the substrate and the heat seal layer or the vapor-deposited heat seal layer, between the substrate and the barrier film, between the barrier film and the heat seal layer or the vapor-deposited heat seal layer, etc. This can improve the adhesion between the substrate and the heat seal layer or the vapor-deposited heat seal layer, and the adhesion between other layers.

[0217] For example, the laminate of the present disclosure can be produced by laminating the above-mentioned substrate and a sealant film corresponding to the heat seal layer, or a vapor-deposited film comprising a heat seal layer and a metal vapor-deposited film, via an adhesive layer.

[0218] The adhesive layer contains one or more types of adhesives, such as one-component curing adhesives, two-component curing adhesives, and non-curing adhesives.

[0219] The adhesive may be a solventless adhesive or a solvent-based adhesive. Examples of adhesives include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, urethane adhesives, rubber adhesives, vinyl adhesives, phenol adhesives, and olefin adhesives. Among these, two-component curing urethane adhesives are preferred.

[0220] The adhesive layer may contain one or more additives, such as pigments, dyes, lubricants, colorants, wetting agents, thickeners, coagulants, gelling agents, anti-settling agents, softeners, hardeners, plasticizers, leveling agents, antioxidants, UV absorbers, light stabilizers, and flame retardants.

[0221] The thickness of the adhesive layer is preferably 0.5 μm to 6 μm, more preferably 0.8 μm to 5 μm, and even more preferably 1 μm to 4.5 μm. When the thickness of the adhesive layer is equal to or greater than the lower limit, for example, the adhesion between layers can be improved. When the thickness of the adhesive layer is equal to or less than the upper limit, for example, the recyclability of a packaging container produced using the laminate of the present disclosure can be improved.

[0222] The adhesive layer can be formed by applying an adhesive to the target by a method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, or transfer roll coating, and drying as necessary.

[0223] In one embodiment of the laminate of the present disclosure, the stretched multilayer substrate satisfies the rigidity, strength, and heat resistance required for an outer layer of a packaging container, and the heat-sealable layer enables packaging at low temperatures. Furthermore, the stretched multilayer substrate and the heat-sealable layer are each composed of polyethylene. Therefore, the laminate is suitable as a packaging material that requires recyclability.

[0224] [Application] The laminate of the present disclosure can be suitably used for packaging material applications. The packaging material is used to produce a packaging container. The packaging material comprises the laminate of the present disclosure. The packaging container can be produced by using at least the packaging material comprising the laminate of the present disclosure.

[0225] A packaging container includes the laminate of the present disclosure. Examples of packaging containers include packaging bags, tube containers, and lidded containers. The lidded container includes a container body having a storage section and a lid material joined (heat sealed) to the container body so as to seal the storage section.

[0226] Examples of heat sealing methods include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, and ultrasonic sealing.

[0227] Examples of packaging bags include various types of packaging bags such as a standing pouch type, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a palm seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type.

[0228] The packaging bag may have an easy-to-open portion. Examples of the easy-to-open portion include a notch portion that serves as a starting point for tearing the packaging bag, and a half-cut line formed by laser processing or a cutter as a path for tearing the packaging bag.

[0229] In one embodiment, a packaging bag can be produced by folding the laminate of the present disclosure in half and overlapping it so that the base material is on the outside and the heat seal layer is on the inside, and then heat-sealing the edges, etc. In another embodiment, a packaging bag can be produced by overlapping multiple laminates of the present disclosure so that the heat seal layers face each other, and then heat-sealing the edges, etc. The entire packaging bag may be made of the laminate, or only a portion of the packaging bag may be made of the laminate.

[0230] In one embodiment, the laminate of the present disclosure is used as a lid material for a lidded container.

[0231] The contents to be contained in the packaging container include, for example, liquids, solids, powders, and gels. The contents may be food or beverages, or non-food or beverages such as chemicals, cosmetics, and pharmaceuticals. After the contents are contained in the packaging container, the packaging container can be hermetically sealed by heat-sealing the opening of the packaging container. As described above, the packaging container has excellent aroma retention properties, making it suitable as a packaging container for contents containing aroma components.

[0232] As specific examples of packaging bags, small pouches and standing pouches will be described below. A sachet is a small packaging bag used to hold contents of, for example, 1 g to 200 g, such as sauces, soy sauce, dressings, ketchup, syrup, cooking alcohol, other liquid or viscous seasonings, liquid soups, powdered soups, fruit juices, spices, liquid beverages, jelly-like beverages, instant foods, and other foods and beverages.

[0233] Because the laminate of the present disclosure has the effects described above, it can be suitably used as a packaging material for producing stand-up pouches, and in particular, it can be suitably used as a packaging material for producing monomaterial stand-up pouches.

[0234] Stand-up pouches are used to store contents of, for example, 50 g to 2000 g, including shampoo, rinse, conditioner, hand soap, body soap, air freshener, deodorant, insect repellent, detergent, dressing, cooking oil, mayonnaise, other liquid or viscous seasonings, liquid beverages, jelly-like beverages, instant foods, other foods and beverages, and creams.

[0235] Fig. 4 is a simplified diagram showing an example of the configuration of a stand-up pouch. As shown in Fig. 4, in one embodiment, a stand-up pouch 40 comprises a body portion (side sheets) 41 and a bottom portion (bottom sheet) 42. The side sheets 41 and the bottom sheet 42 may be made of the same material, or may be made of different materials. The bottom sheet maintains the shape of the side sheets, thereby imparting self-supporting properties to the pouch and enabling it to be a standing pouch. A storage space for storing contents is formed within the area surrounded by the side sheets and the bottom sheet.

[0236] In a stand-up pouch, only the body portion may be made of the laminate of the present disclosure, only the bottom portion may be made of the laminate of the present disclosure, or both the body portion and the bottom portion may be made of the laminate of the present disclosure.

[0237] In one embodiment, the side sheets can be formed by preparing two laminates of the present disclosure, overlapping them with their heat-sealable layers facing each other, and heat-sealing both side edges to form a bag.

[0238] In another embodiment, the side sheets can be formed by preparing two laminates of the present disclosure, overlapping them with their heat-sealable layers facing each other, and inserting two V-folded laminates with their heat-sealable layers facing outward between the laminates at the side edges of both sides of the overlapped laminates, and heat-sealing them. This production method provides a standing pouch 40 having a body portion 41 with side gussets 43, as shown in FIG. 5.

[0239] In one embodiment, the bottom sheet can be formed by inserting the laminate of the present disclosure between the lower portions of the side sheets of a bag and heat-sealing the laminate. More specifically, the bottom sheet can be formed by inserting the laminate folded in a V-shape with the heat-seal layer facing outward between the lower portions of the side sheets of a bag and heat-sealing the laminate.

[0240] In one embodiment, two of the laminates are prepared and stacked together with their heat-sealable layers facing each other. Then, the other laminate is folded in a V-shape with the heat-sealable layer facing outward, and the folded laminate is sandwiched between the two laminates and heat-sealed to form a bottom. The two sides adjacent to the bottom are then heat-sealed to form a body. In this manner, a standing pouch according to one embodiment can be formed.

[0241] The present disclosure relates to, for example, the following [1] to

[13] . [1] A laminate comprising a substrate made of polyethylene and a heat seal layer, wherein the heat seal layer has a density of 0.925 g / cm 3 A laminate comprising the following polyethylene resin layer (1) and a barrier resin layer containing a gas barrier resin, wherein the polyethylene resin layer (1) is the surface layer on one side of the laminate. [2] The laminate according to the above [1], wherein the gas barrier resin is at least one selected from polyamide, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyacrylonitrile, polyester, polyurethane, and polyvinylidene chloride. [3] The laminate according to the above [1] or [2], wherein the barrier resin layer contains a polyamide. [4] The laminate according to any one of the above [1] to [3], wherein the barrier resin layer contains an aliphatic polyamide, and the content of the aliphatic polyamide in the barrier resin layer is more than 50 mass %. [5] The laminate according to any one of the above [1] to [4], wherein the resin layer (1) contains linear low-density polyethylene, and the content of linear low-density polyethylene in the resin layer (1) is 80 mass% or more. [6] The laminate according to any one of the above [1] to [5], wherein the heat seal layer further comprises a polyethylene resin layer (2) as a surface layer of the heat seal layer on the substrate side. [7] The laminate according to any one of the above [1] to [6], wherein each layer constituting the heat seal layer is a coextruded resin layer. [8] The laminate according to any one of the above [1] to [7], wherein the heat seal layer is an unstretched film. [9] The laminate according to any one of the above [1] to [8], wherein the content of polyethylene in the entire heat seal layer is 80% by mass or more.

[10] The laminate according to any one of the above [1] to [9], wherein the substrate is a stretched substrate.

[11] The laminate according to any one of the above [1] to

[10] , wherein the substrate is a stretched multilayer substrate.

[12] The laminate according to any one of the above [1] to

[11] , further comprising a printed layer on the substrate.

[13] A packaging container comprising the laminate according to any one of [1] to

[12] above. [Example]

[0242] The laminate of the present disclosure will be described in more detail based on examples, but the laminate of the present disclosure is not limited to the examples. Hereinafter, "parts by mass" will be simply referred to as "parts".

[0243] In the following description, high-density polyethylene will also be referred to as "HDPE," medium-density polyethylene as "MDPE," low-density polyethylene as "LDPE," and linear low-density polyethylene as "LLDPE."

[0244] [Preparation of substrate] The polyethylene used in the preparation of the substrate will be described. Medium Density Polyethylene: Product name: Elite 5538G (hereinafter referred to as "MDPE(1)") Density: 0.941g / cm 3 , Melting point: 129℃, MFR: 1.3g / 10min, Dowchemical Medium Density Polyethylene: Product name: Enable4002MC (hereinafter referred to as "MDPE(2)") Density: 0.940g / cm 3 , Melting point: 128℃, MFR: 0.25g / 10min, ExxonMobil High density polyethylene: Product name: Elite 5960G (hereinafter referred to as "HDPE (1)") Density: 0.960g / cm 3 , Melting point: 134℃, MFR: 0.8g / 10min, Dowchemical High density polyethylene: Product name: H619F (hereinafter referred to as "HDPE (2)") Density: 0.965g / cm 3 , Melting point: 135℃, MFR: 0.7g / 10min, Made by SCG Linear low density polyethylene: Product name: Elite 5400G (hereinafter referred to as "LLDPE(1)") Density: 0.916g / cm 3 , Melting point: 123℃, MFR: 1.3g / 10min, Dowchemical Linear low density polyethylene: Product name: Exceed XP8656ML (hereinafter referred to as "LLDPE(2)") Density: 0.916g / cm 3 , Melting point: 121℃, MFR: 0.5g / 10min, ExxonMobil Low-density polyethylene: Product name: LD2420F (hereinafter referred to as "LDPE (1)") Density: 0.922g / cm 3 , Melting point: 112℃, MFR: 0.75g / 10min, Made by PTT MB containing slip agent: Product name: SLIP61 10061-K Density: 0.910g / cm 3 , MFR:10g / 10min, Polyethylene base, contains 5% by weight of erucic acid amide slip agent Ampacet

[0245] Blended polyethylene (A) 50 parts of MDPE (1) and 50 parts of HDPE (1) were mixed to produce a mixture with a density of 0.951 g / cm 3 A blended polyethylene (hereinafter also referred to as "blend PE(A)") was obtained.

[0246] Blended polyethylene (B) 50 parts of MDPE (1) and 50 parts of LLDPE (1) were mixed to produce a density of 0.929 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (B)") was obtained.

[0247] Blended polyethylene (B1) 70 parts of MDPE (1) and 30 parts of LLDPE (1) were mixed to obtain a density of 0.934 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (B1)") was obtained.

[0248] Blended polyethylene (C) 70 parts of MDPE (1) and 30 parts of HDPE (1) were mixed to produce a density of 0.947 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE(C)") was obtained.

[0249] Blended polyethylene (D) 30 parts of MDPE (1) and 70 parts of HDPE (1) were mixed to produce a density of 0.954 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (D)") was obtained.

[0250] Blended polyethylene (A1) 70 parts of MDPE (2) and 30 parts of HDPE (1) were mixed to produce a density of 0.948 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (A1)") was obtained. Blended polyethylene (B2) 70 parts of HDPE (2) and 30 parts of LDPE (1) were mixed to give a density of 0.950 g / cm 3A blended polyethylene (hereinafter also referred to as "blended PE (B2)") was obtained. Blended polyethylene (C1) 98 parts of LLDPE (2) and 2 parts of MB containing slip agent were mixed to give a density of 0.916 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (C1)") was obtained.

[0251] Blended polyethylene (A2) 69 parts of MDPE (2), 30 parts of HDPE (1), and 1 part of MB containing slip agent were mixed to produce a composite with a density of 0.948 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (A2)") was obtained. Blended polyethylene (B3) 69 parts of HDPE (2), 30 parts of LDPE (1), and 1 part of MB containing slip agent were mixed to produce a composite with a density of 0.949 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (B3)") was obtained. Blended polyethylene (C2) 99 parts of LLDPE (2) and 1 part of slip agent-containing MB were mixed to produce a density of 0.916 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (C2)") was obtained.

[0252] Blended polyethylene (C3) 68 parts of LLDPE (2), 30 parts of LDPE (1), and 2 parts of MB containing slip agent were mixed to obtain a density of 0.918 g / cm 3 A blended polyethylene (hereinafter also referred to as "blended PE (C3)") was obtained.

[0253] [Manufacturing Example 1] MDPE (1), HDPE (1), and blend PE (A) were coextruded by inflation molding to form a five-layer film with a layer thickness ratio of MDPE (1) layer (15 μm) / HDPE (1) layer (22.5 μm) / blend PE (A) layer (50 μm) / HDPE (1) layer (22.5 μm) / MDPE (1) layer (15 μm), yielding a polyethylene film with a total thickness of 125 μm. The numbers in parentheses indicate the layer thicknesses.

[0254] The polyethylene film prepared above was stretched in the machine direction (MD) at a stretching ratio of 5 times to obtain a stretched multilayer substrate (1) having a thickness of 25 μm.

[0255] [Manufacturing Examples 2 to 8] Stretched multilayer substrates (2) to (8) were obtained in the same manner as in Production Example 1, except that the layer structure of the stretched multilayer substrate was changed as shown in Tables 1 and 2. In Table 2, the MB containing a slip agent is simply referred to as "MB."

[0256] [Manufacturing Example 9] Blend PE (A1), blend PE (B2), and blend PE (C1) were coextruded by inflation molding to form a five-layer polyethylene film with a total thickness of 100 μm, with a layer thickness ratio of blend PE (A1) layer (12 μm), blend PE (B2) layer (18 μm), blend PE (C1) layer (40 μm), blend PE (B2) layer (18 μm), and blend PE (A1) layer (12 μm). The numbers in parentheses indicate the layer thicknesses.

[0257] The polyethylene film prepared above was stretched in the machine direction (MD) at a stretching ratio of 5 times to obtain a stretched multilayer substrate (9) having a thickness of 20 μm.

[0258] [Manufacturing Examples 10-11] Stretched multilayer substrates (10) to (11) were obtained in the same manner as in Production Example 9, except that the layer structure of the stretched multilayer substrate was changed as shown in Table 2. In Table 2, the slip agent-containing MB is simply referred to as "MB."

[0259] [Haze Rating] The haze value of the stretched multilayer substrate prepared above was measured in accordance with JIS K7136.

[0260] [Rigidity evaluation] The stretched multilayer substrate prepared above was cut into test pieces with a width of 10 mm, and the stiffness of the test pieces was measured using a loop stiffness measuring tester (manufactured by Toyo Seiki Seisakusho, product name: Loop Stiffness Tester). The loop length was 60 mm.

[0261] [Strength evaluation] A 10 mm wide dumbbell-shaped test piece was cut from the stretched multilayer substrate prepared above. The tensile strength of the dumbbell-shaped test piece in the MD direction was measured using a tensile tester (Orientec Co., Ltd., RTC-1310A). The chuck distance was 10 mm and the tensile speed was 300 mm / min. [Printability evaluation] An image was formed on the stretched multilayer substrate prepared above by gravure printing using an oil-based gravure ink (manufactured by DIC Graphics Corporation, trade name: Finart). The formed image was visually observed and evaluated based on the following evaluation criteria. (Evaluation criteria) AA: Good dimensional stability during printing. A good image was formed without any rubbing or bleeding. BB: The film expands and contracts during printing. The formed image was smeared and blurred.

[0262] [Table 1]

[0263] [Table 2]

[0264] [Example 1] <Preparation of sealant film> 55 parts of LLDPE(a) (density: 0.920 g / cm 3 , melting point: 119°C, MFR: 1.0g / 10min, manufactured by Dowchemical, trade name: Dowlex 2045G) 45 parts HDPE(a) (density: 0.951 g / cm 3 , melting point: 131°C, MFR: 1.1g / 10min, manufactured by PTT, trade name: HD3355F) These were kneaded to obtain a blended polyethylene (hereinafter also referred to as "blended PE(a)"). The density of blended PE (a) is 0.934 g / cm 3 It was.

[0265] Blend PE (a) and adhesive resin A (maleic acid-modified polyethylene, density: 0.910 g / cm 3 , MFR: 2.3 g / 10 min, Mitsui Chemicals, Inc., product name: Admer NF528T) and polyamide A (6 / 66 copolymer nylon resin, density: 1.12 g / cm 3 A multilayer film was extruded using an inflation molding method with a blended PE (a) layer (60 μm), adhesive resin A layer (4 μm), polyamide A layer (12 μm), adhesive resin A layer (4 μm), and LLDPE (a) layer (60 μm) to produce a five-layer, unstretched sealant film (1) (total thickness 140 μm). The numbers in parentheses indicate the layer thicknesses.

[0266] <Preparation of laminate> The stretched multilayer substrate (1) produced in Production Example 1 and the sealant film (1) produced above were laminated via a two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-77T / H-7) so that the blend PE (a) layer of the sealant film (1) faced the stretched multilayer substrate (1) to obtain a laminate. The thickness of the adhesive layer formed with the two-component curing urethane adhesive was 3.0 μm.

[0267] [Examples 2 to 11] Laminates were obtained in the same manner as in Example 1, except that the stretched multilayer substrates (2) to (11) were used instead of the stretched multilayer substrate (1).

[0268] [Reference example 1] Blend PE (a) and LLDPE (a) were extruded into a multilayer film by inflation molding to produce a two-layer, unstretched sealant film (c1) (total thickness 140 μm) with a blend PE (a) layer (80 μm) and an LLDPE (a) layer (60 μm). The numbers in parentheses indicate the layer thicknesses. A laminate was produced in the same manner as in Example 1, except that sealant film (c1) was used instead of sealant film (1).

[0269] [Comparative Example 1] Blend PE (a), adhesive resin A, polyamide A, and MDPE (a) (density: 0.935 g / cm 3 A five-layer unstretched sealant film (c2) (total thickness 140 μm) was produced using a multilayer extrusion film consisting of a blend PE (a) layer (60 μm), adhesive resin A layer (4 μm), polyamide A layer (12 μm), adhesive resin A layer (4 μm), and MDPE (a) layer (60 μm). A laminate was produced in the same manner as in Example 1, except that sealant film (c2) was used instead of sealant film (1).

[0270] [Seal strength evaluation] The laminates obtained in the Examples, Reference Examples, and Comparative Examples were cut into 10 cm x 10 cm pieces to prepare three test pieces for each. Each test piece was folded in half with the sealant film (heat seal layer) side facing inward, and tested at a temperature of 140°C and a pressure of 1 kgf / cm using a heat seal tester. 2 An area of ​​1 cm x 10 cm was heat-sealed under the conditions of 1 second, 1 minute, 1 minute.

[0271] The heat-sealed test piece was cut into 15 mm wide strips, and both ends that were not heat-sealed were held with a tensile tester to measure the peel strength (N / 15 mm) at a speed of 300 mm / min and a load range of 50 N. In Comparative Example 1, the heat-sealed layer was not sufficiently fused due to insufficient heat, and sufficient seal strength was not obtained.

[0272] [Standing pouch bag making evaluation] Using a bag making machine, standing pouches measuring 110 mm long x 150 mm wide were produced from the laminates obtained in the Examples, Reference Examples, and Comparative Examples. The bag-making method involved first preparing one test piece measuring 110 mm long x 60 mm wide from the laminate, and folding it into a V shape with the sealant film (heat-seal layer) facing outward (110 mm long x 30 mm wide). Next, two laminates were stacked with the sealant films (heat-seal layers) facing each other, and the V-shaped test piece obtained above was sandwiched at one end and heat-sealed with a heat-seal bar at 140 ° C. to form a bottom. Subsequently, two sides adjacent to the bottom were similarly heat-sealed to form a tubular body, which was then cut to a size of 110 mm long x 150 mm wide to produce a standing pouch.

[0273] The bag-making suitability of the standing pouches was evaluated based on the following evaluation criteria. AA: The heat-sealed layers were fused together, and a standing pouch could be produced using a bag-making machine. BB: The heat seal layers do not fuse together, It was not possible to produce a standing pouch with sufficient seal strength.

[0274] [Aroma retention evaluation] 0.1 g of L-menthol was placed in the standing pouch prepared above, and the top was heat-sealed at 140° C. Each heat-sealed standing pouch was placed in a glass bottle, which was then capped and stored at 23° C. for one week, after which the odor inside the glass bottle was checked. AA: No odor of L-menthol was detected inside the glass bottle. BB: The odor of L-menthol was detected inside the glass bottle.

[0275] [Table 3]

[0276] [Table 4] [Explanation of symbols]

[0277] 1: Laminate 2: Heat seal layer 10: Resin layer (1) 11: Barrier resin layer 12: Resin layer (2) 13:Adhesive resin layer 30: Base material 32: Adhesive layer 40: Standing pouch 41: Body (side sheet) 42: Bottom (bottom sheet) 43: Side gusset

Claims

1. A substrate made of polyethylene; Heat seal layer and A laminate comprising: The heat seal layer is Density is 0.925 g / cm ３ The following polyethylene resin layer (1): a barrier resin layer containing a gas barrier resin; Equipped with The surface layer on one side of the laminate is the polyethylene resin layer (1). Laminate.

2. 2. The laminate according to claim 1, wherein the gas barrier resin is at least one selected from the group consisting of polyamide, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyacrylonitrile, polyester, polyurethane, and polyvinylidene chloride.

3. The laminate according to claim 1 or 2, wherein the barrier resin layer contains a polyamide.

4. 4. The laminate according to claim 1, wherein the barrier resin layer contains an aliphatic polyamide, and the content of the aliphatic polyamide in the barrier resin layer is more than 50% by mass.

5. The laminate according to any one of claims 1 to 4, wherein the resin layer (1) contains linear low-density polyethylene, and the content of the linear low-density polyethylene in the resin layer (1) is 80 mass% or more.

6. The laminate according to any one of claims 1 to 5, wherein the heat seal layer further comprises a polyethylene resin layer (2) as a surface layer of the heat seal layer on the substrate side.

7. The laminate according to any one of claims 1 to 6, wherein each layer constituting the heat seal layer is a coextruded resin layer.

8. The laminate according to any one of claims 1 to 7, wherein the heat seal layer is an unstretched film.

9. The laminate according to any one of claims 1 to 8, wherein the content of polyethylene in the entire heat seal layer is 80 mass% or more.

10. The laminate according to any one of claims 1 to 9, wherein the substrate is a stretched substrate.

11. The laminate according to any one of claims 1 to 10, wherein the substrate is a stretched multilayer substrate.

12. The laminate according to any one of claims 1 to 11, further comprising a printed layer on the substrate.

13. A packaging container comprising the laminate according to any one of claims 1 to 12.

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