Gas barrier film, laminate, packaging bag, and package

Abstract

Provided is a gas barrier film comprising a polyethylene-containing base material, and a barrier layer formed on one surface side of the base material. The barrier layer includes at least one of an inorganic layer and a gas barrier film. The base material has a crystallinity of 35.0% or less, the crystallinity being the ratio of the crystal peak area to the total peak area in a diffraction angle range of 10-30° in an X-ray diffraction pattern obtained by measuring X-ray diffraction by means of a parallel beam method. The ratio of the crystal peak area of a (200) plane of the polyethylene to the total peak area is 2.0% or higher.

Description

Gas barrier film, laminate, packaging bag, and packaging body

[0001] The present disclosure relates to a gas barrier film, a laminate, a packaging bag, and a package.

[0002] Packaging bags used for packaging foods, medicines, etc. are required to have gas barrier properties, i.e., properties that prevent the intrusion of gases such as water vapor and oxygen that denature the contents, in order to prevent deterioration and spoilage of the contents and maintain their functionality and quality. For this reason, laminates (gas barrier films) with gas barrier properties are used for these packaging bags.

[0003] Known gas barrier films include those in which a gas barrier layer made of a material having gas barrier properties is provided on the surface of a substrate, and examples of the gas barrier layer include metal foil, metal vapor deposition film, and film formed by a wet coating method.

[0004] Known examples of the above-mentioned coatings that exhibit oxygen barrier properties include resin films formed from coating agents containing water-soluble polymers and resins such as polyvinylidene chloride, and inorganic layered mineral composite resin films formed from coating agents containing water-soluble polymers and inorganic layered minerals (Patent Document 1).

[0005] Further, as a gas barrier layer, a gas barrier layer in which a vapor-deposited thin film layer made of an inorganic oxide and a gas barrier composite coating containing an aqueous polymer, an inorganic layered compound, and a metal alkoxide are laminated in this order (Patent Document 2), and a gas barrier layer containing a polyvalent metal salt of a polycarboxylic acid polymer, which is a reaction product of a carboxy group of a polycarboxylic acid polymer and a polyvalent metal compound (Patent Document 3) have been proposed.

[0006] Japanese Patent No. 6191221 Japanese Patent Laid-Open No. 2000-254994 Japanese Patent No. 4373797

[0007] However, gas barrier films having such a gas barrier layer may have insufficient peel strength at the substrate surface layer, and the substrate may easily peel off when joined to the heat seal layer, resulting in insufficient adhesive strength between the substrate and the heat seal layer.

[0008] Furthermore, when a polyethylene film is used as the base material of a gas barrier film, if the film is subjected to a heat sterilization treatment such as boiling, the water vapor barrier properties of the gas barrier film deteriorate, resulting in the problem that sufficient water vapor barrier properties cannot be ensured.

[0009] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a gas barrier film, a laminate, a packaging bag, and a packaging body that have excellent water vapor barrier properties, can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment, and have high adhesion between themselves and a heat seal layer.

[0010] One aspect of the present disclosure provides a gas barrier film comprising: a substrate containing polyethylene; and a barrier layer formed on one side of the substrate, wherein the barrier layer comprises at least one of an inorganic layer and a gas barrier coating; and wherein, in an X-ray diffraction pattern obtained by measuring the substrate using a parallel beam X-ray diffraction method, the substrate has a crystallinity, which is the proportion of a crystalline peak area to a total peak area in a diffraction angle range of 10° to 30°, of 35.0% or less, and the proportion of a crystalline peak area due to the (200) plane of polyethylene to the total peak area is 2.0% or more.

[0011] The gas barrier film has excellent water vapor barrier properties, can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment, and has high adhesion to the heat seal layer.

[0012] The density of the polyethylene contained in the gas barrier film is 0.940 g / cm ３ In this case, the substrate is more likely to be prevented from stretching and wrinkling during roll processing of the gas barrier film. Furthermore, cracks are more likely to be prevented from occurring in the barrier layer, thereby suppressing deterioration of the water vapor barrier property of the gas barrier film.

[0013] The substrate is preferably a non-stretched film, in which case higher adhesive strength is likely to be obtained between the substrate and other layers.

[0014] The inorganic layer is preferably made of aluminum oxide or silicon oxide, which has excellent productivity and excellent oxygen barrier properties and water vapor barrier properties under heat or moist heat conditions.

[0015] The gas barrier coating is preferably a coating obtained using a composition containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide, and a water-soluble polymer, in which case the gas barrier film has superior oxygen barrier properties and superior water vapor barrier properties.

[0016] It is more preferred that the composition further contains at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent, in which case the gas barrier film has better oxygen barrier properties.

[0017] The gas barrier coating preferably contains a polyvalent metal salt of a polycarboxylic acid polymer, in which case the gas barrier film has superior oxygen barrier properties and superior water vapor barrier properties.

[0018] The substrate is a multilayer polyethylene film having a surface layer, an intermediate layer, and a back layer, and the multilayer polyethylene film is preferably formed by an inflation method in which the polyethylenes forming the surface layer, intermediate layer, and back layer are each fed into an extruder, melt-kneaded, and then discharged from the extruder through a die. In this case, the functions required for a gas barrier film can be individually imparted to each of the surface layer, intermediate layer, and back layer, making it easier to improve processing stability, heat resistance, mechanical strength, barrier properties, etc.

[0019] Another aspect of the present disclosure provides a laminate including the gas barrier film and a heat seal layer joined to the gas barrier film so as to sandwich the barrier layer between a substrate.

[0020] The laminate has sufficient durability due to the high adhesion between the gas barrier film and the heat seal layer. Furthermore, the gas barrier film has excellent water vapor barrier properties, and deterioration of the water vapor barrier properties is suppressed even when subjected to heat sterilization treatment. Therefore, the laminate has excellent water vapor barrier properties, and deterioration of the water vapor barrier properties is suppressed even when subjected to heat sterilization treatment.

[0021] The heat seal layer preferably contains polyethylene. According to the laminate, since both the substrate and the heat seal layer contain polyethylene, the laminate has recyclability.

[0022] The laminate may further include an adhesive layer that bonds the gas barrier film and the heat seal layer. It is more preferable that the adhesive layer is obtained using a gas barrier adhesive. In this case, the adhesive layer also has gas barrier properties, so that the laminate has better gas barrier properties.

[0023] The adhesive layer is preferably obtained using a solvent-free adhesive. In this case, the environmental impact of the laminate can be reduced. The solvent-free adhesive more preferably includes a two-component curing urethane adhesive. In this case, the adhesion between the adhesive layer and the barrier layer or the heat seal layer is improved, and the laminate has sufficient durability.

[0024] The laminate may further include a second adhesive layer and a surface substrate layer in this order on the surface opposite the heat seal layer of the substrate. In this case, the substrate is reinforced by the surface substrate layer via the second adhesive layer, so that the laminate has better strength.

[0025] Another aspect of the present disclosure provides a packaging bag formed using the above-mentioned laminate. The packaging bag has excellent water vapor barrier properties and can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment. Furthermore, since the gas barrier film has high adhesion to the heat seal layer, the packaging bag has sufficient durability.

[0026]

[0010] Yet another aspect of the present disclosure provides a package including the above-described packaging bag and contents accommodated within the packaging bag. According to the above-described package, the packaging bag has excellent water vapor barrier properties, and deterioration of the water vapor barrier properties can be suppressed even when the packaging bag is subjected to a heat sterilization treatment, thereby preventing the contents accommodated within the packaging bag from being exposed to water vapor and deteriorating in quality. Furthermore, high adhesion is achieved between the gas barrier film and the heat seal layer, resulting in sufficient durability of the package.

[0027] In yet another aspect of the present disclosure, there is provided a film further comprising an adhesive layer between the barrier layer and the heat seal layer, and an undercoat layer between the substrate and the barrier layer, the barrier layer having, from the undercoat layer side, an inorganic layer and a gas barrier film in this order, the adhesive layer being a layer that bonds the gas barrier film and the heat seal layer, the substrate being an unstretched film consisting of a surface layer, an intermediate layer, and a back layer, the density of the substrate being 0.940 g / cm3 or more, and the thickness of the substrate being the thickness of the intermediate layer to the thickness of the surface layer is 2 to 3; the inorganic layer is made of silicon oxide; the thickness of the undercoat layer is 0.01 μm to 0.1 μm; the thickness of the inorganic layer is 10 nm to 30 nm; and the gas barrier coating is made of at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide. and a water-soluble polymer, wherein the heat-sealable layer is a layer made of linear low-density polyethylene, and the adhesive layer is a layer obtained using a solventless adhesive; the X-ray diffraction pattern is an X-ray diffraction pattern obtained by out-of-plane measurement using a wide-angle X-ray diffractometer to perform 2θ / θ scanning over a diffraction angle range of 10° to 30°; and the area of ​​the crystalline peak obtained by separating and analyzing a crystalline peak derived from a crystalline component and a halo pattern derived from an amorphous component in the X-ray diffraction pattern is S1; the area of ​​the halo pattern is S2; and the area of ​​the crystalline peak corresponding to the (200) plane of polyethylene obtained by separating and analyzing peaks corresponding to the (110) plane and the (200) plane of polyethylene in the crystalline peak is S3. The crystallinity is a value calculated by the following formula (1), and the proportion is calculated by the following formula (2). The crystallinity is 15.0% to 35.0%, and the proportion is 2.0% to 7.0%. Crystallinity (%) = 100 × S1 / (S1 + S2) (1) Ratio (%) = 100 × S3 / (S1 + S2) (2) In this case, the laminate has better water vapor barrier properties, and deterioration of the water vapor barrier properties can be effectively suppressed even when subjected to heat sterilization treatment.Furthermore, since there is high adhesion between the gas barrier film and the heat seal layer, the laminate has sufficient durability.

[0028] The present disclosure provides a gas barrier film, a laminate, a packaging bag, and a packaging body that have excellent water vapor barrier properties, can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment, and have high adhesion between the film and the heat seal layer.

[0029] Fig. 1 is a cross-sectional view schematically showing one embodiment of a laminate according to the present disclosure. Fig. 2 is a cross-sectional view schematically showing another embodiment of a laminate according to the present disclosure. Fig. 3 is a cross-sectional view schematically showing another embodiment of a laminate according to the present disclosure. Fig. 4 is a cross-sectional view schematically showing one embodiment of a package according to the present disclosure.

[0030] [Laminate] Hereinafter, an embodiment of a laminate according to the present disclosure will be described with reference to Figs. 1 and 2. Fig. 1 is a cross-sectional view schematically showing one embodiment of a laminate according to the present disclosure, and Fig. 2 is a cross-sectional view schematically showing another embodiment of a laminate according to the present disclosure. As shown in Fig. 1, a laminate 30 includes a gas barrier film 10 and a heat seal layer 4. The gas barrier film 10 is one embodiment of the gas barrier film according to the present disclosure. The gas barrier film 10 and the heat seal layer 4 may be joined by an adhesive layer 6.

[0031] The gas barrier film 10 comprises a substrate 1 and a barrier layer 8 formed on a first surface 1a of the substrate 1. In an X-ray diffraction pattern obtained by measuring the substrate 1 using a parallel beam X-ray diffraction method, the crystallinity, which is the ratio of the crystalline peak area to the total peak area in the diffraction angle range of 10° to 30°, is 35.0% or less, and the ratio of the crystalline peak area of ​​the polyethylene (200) plane to the total peak area is 2.0% or more. The barrier layer 8 may comprise either an inorganic layer 7 or a gas barrier coating 2, or may comprise both the inorganic layer 7 and the gas barrier coating 2 as shown in FIG. 1. The gas barrier film 10 may further comprise an undercoat layer 9 on the first surface 1a of the substrate 1, as in the laminate 32 shown in FIG. 2. In other words, the gas barrier film 10 may further comprise an undercoat layer 9 between the substrate 1 and the barrier layer 8.

[0032] The gas barrier film 10 has excellent water vapor barrier properties, can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment, and has high adhesion to the heat seal layer 4. Therefore, the laminate 30 has sufficient durability. Furthermore, since the gas barrier film 10 has excellent water vapor barrier properties and can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment, the laminate 30 has excellent water vapor barrier properties and can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment.

[0033] The configurations of the gas barrier film 10, the adhesive layer 6 and the heat seal layer 4 will be described below.

[0034] <Gas Barrier Film> (1) Substrate The substrate 1 contains polyethylene (PE). The substrate 1 may be a monolayer film made of a polyethylene-containing PE layer, or a laminate film having at least one polyethylene-containing PE layer. When the substrate 1 is a laminate film, the substrate 1 may have a surface layer 12, an intermediate layer 13, and a back layer 14, as shown in FIG. 2 . Here, the surface layer 12 is a layer that constitutes the surface of the substrate 1 opposite the barrier layer 8 (first surface 1a), the back layer 14 is a layer that constitutes the surface of the substrate 1 facing the barrier layer 8 (second surface, which is the surface of the substrate 1 opposite the first surface 1a), and the intermediate layer 13 is a layer located between the surface layer 12 and the back layer 14. In addition to the PE layer, the laminate film may further include a resin layer containing a resin other than polyethylene, or a non-resin layer containing metal, wood, paper, ceramics, or the like. The substrate 1 is preferably a multilayer polyethylene film having the surface layer 12, the intermediate layer 13, and the back layer 14. From the viewpoint of recyclability, it is preferable that the resin layer in the substrate 1 be a layer containing a polyethylene-containing resin. When the substrate 1 is a laminated film, it is preferable that all layers included in the laminated film are layers made of a resin containing polyethylene.

[0035] The polyethylene may be at least one polymer selected from a homopolymer, a random copolymer, and a block copolymer. A homopolymer is a polyethylene whose only constituent unit is ethylene, and a random copolymer is a polyethylene in which ethylene, the main monomer, and a comonomer different from ethylene are randomly copolymerized to form a homogeneous phase. A block copolymer is a polyethylene in which ethylene, the main monomer, and the comonomer are copolymerized in a block manner or polymerized in a rubber-like manner to form a heterogeneous phase. Examples of the comonomer include α-olefins such as butene-1, hexene-1, octene-1, and 4-methylpentene-1.

[0036] The density of the polyethylene contained in the substrate 1 is 0.940 g / cm ３ It is preferable that the density is 0.945 g / cm or more. ３ It is more preferable that the density of polyethylene is 0.940 g / cm or more. ３ If the above conditions are met, the substrate 1 is more likely to be prevented from stretching and wrinkling during the roll processing of the gas barrier film 10. Furthermore, the barrier layer 8 (particularly the inorganic layer 7) is more likely to be prevented from cracking.

[0037] The substrate 1 may have a multilayer structure including multiple layers (films) each containing polyethylene of different densities. It is desirable to appropriately multilayer the substrate 1, taking into consideration the processability, rigidity, stiffness, heat resistance, and powder shedding during transport of the films constituting each layer. The films constituting the substrate 1 can be produced by appropriately selecting high-density polyolefin, medium-density polyolefin, low-density polyolefin, etc. In this case, the density of the substrate 1 as a whole is measured to be 0.940 g / cm. ３ It is preferable that the density is 0.945 g / cm or more. ３ More preferably, it is equal to or greater than this.

[0038] The substrate 1 may be an unstretched film or a stretched film such as a uniaxially stretched film or a biaxially stretched film, but is preferably an unstretched film because it is more likely to achieve higher adhesion strength with other layers.

[0039] Each layer of the substrate 1 may contain additives such as fillers, antiblocking agents, slip agents, antistatic agents, plasticizers, lubricants, or antioxidants. These additives may be used singly or in combination. Furthermore, the content or percentage of each additive may differ in each layer of the substrate 1. A substrate 1 having multiple layers can be produced using extrusion coating, coextrusion coating, sheet molding, coextrusion blow molding, inflation molding, or the like. When the substrate 1 is a multilayer polyethylene film having a surface layer 12, an intermediate layer 13, and a back layer 14, the substrate 1 is preferably produced by feeding the polyethylenes forming the surface layer 12, the intermediate layer 13, and the back layer 14 into an extruder, melt-kneading the polyethylene, and then discharging the polyethylene from the extruder through a die (e.g., a three-layer die) using an inflation method. In this case, the functions required for a gas barrier film can be individually imparted to each of the surface layer 12, the intermediate layer 13, and the back layer 14, which facilitates improving processing stability, heat resistance, mechanical strength, barrier properties, and the like.

[0040] The surface of the substrate 1 that comes into contact with the barrier layer 8 (first surface 1a) may be subjected to a surface treatment such as chemical treatment, solvent treatment, corona treatment, low-temperature plasma treatment, or ozone treatment in order to improve adhesion to the barrier layer 8. Furthermore, a similar surface treatment may be applied to a second surface of the substrate 1 that is the surface opposite to the first surface 1a, for the purpose of bonding it to another layer such as a printed layer.

[0041] The thickness of the substrate 1 is not particularly limited and can be appropriately determined according to the price and application, taking into consideration the suitability as a packaging material and the suitability for laminating other films. The thickness of the substrate 1 is preferably 3 μm to 200 μm in practice, more preferably 5 μm to 120 μm, even more preferably 6 μm to 100 μm, particularly preferably 10 μm to 40 μm, and most preferably 15 μm to 35 μm.

[0042] When the substrate 1 has a surface layer 12, an intermediate layer 13, and a back layer 14, the thickness of each layer is not particularly limited as long as the total thickness of these layers does not exceed the thickness of the substrate 1. The thicknesses of the surface layer 12 and the back layer 14 may be the same or different, but are preferably the same. Furthermore, the ratio of the thickness of the intermediate layer 13 to the thickness of the surface layer 12 is not particularly limited, but is preferably 2 to 3.

[0043] (Method for determining crystallinity) The crystallinity of the substrate 1 is determined based on an X-ray diffraction pattern obtained by measurement using an X-ray diffraction method (parallel beam method of X-ray diffraction) using a parallel beam optical system. The method for determining the crystallinity of the substrate 1 will be described below.

[0044] First, an X-ray diffraction pattern of the substrate 11 is obtained by out-of-plane measurement using a wide-angle X-ray diffractometer manufactured by Rigaku Corporation, and 2θ / θ scanning is performed over a diffraction angle range of 10° to 30°. The characteristic X-rays used are CuKα X-rays, which are collimated by a multilayer mirror and incident on the substrate 1, and a scintillation detector equipped with a flat collimator is used as the light-receiving unit.

[0045] In the obtained X-ray diffraction pattern, peaks (crystalline peaks) derived from crystalline components and halo patterns derived from amorphous components appear in the diffraction angle range of 10° to 30°. These are separated and analyzed to determine the crystalline peak area S1 and the halo pattern area S2. The sum of these areas, S (= S1 + S2), is taken as the total peak area. The crystallinity is determined based on the following formula (1): Crystallinity (%) = 100 × S1 / S (= S1 + S2) (1)

[0046] Although the focusing method is known as an X-ray diffraction method other than the parallel beam method, in the case of samples with an uneven surface such as a resin film, the focusing method is prone to affecting the measurement results, such as peak broadening due to misalignment of the measurement surface.In contrast, in the case of the parallel beam method, misalignment of the measurement surface has little effect on the measurement results, even in the case of samples with an uneven surface.

[0047] The crystallinity of the substrate 1 is 35.0% or less. A crystallinity of 35.0% or less ensures high adhesion between the gas barrier film 10 and the heat seal layer 4. The gas barrier film 10 also has excellent water vapor barrier properties, and can suppress deterioration of the water vapor barrier properties even when subjected to a heat sterilization treatment. The crystallinity of the substrate 1 may be 30.0% or less or 25.0% or less. The crystallinity may also be 5.0% or more, 10.0% or more, 15.0% or more, or 20.0% or more. The range of the crystallinity may be 5.0% to 35.0%, 5.0% to 30.0%, 10.0% to 35.0%, 10.0% to 30.0%, 15.0% to 35.0%, or 15.0% to 30.0%.

[0048] Furthermore, since the substrate 1 contains polyethylene, when a 2θ / θ scan is performed at a diffraction angle range of 10° to 30°, two sharp crystalline component peaks corresponding to the (110) and (200) planes of polyethylene and a broad halo pattern of amorphous components are observed. Here, these are separated and analyzed to determine the crystalline peak area S3 corresponding to the (200) plane of polyethylene. The proportion R of the crystalline peak area S3 of the (200) plane of polyethylene to the total peak area S is determined based on the following formula (2): R (%) = 100 × S3 / S (= S1 + S2) ... (2) The proportion R of the crystalline peak area S3 of the (200) plane of polyethylene to the total peak area S is 2.0% or more. By having the proportion R of 2.0% or more, the gas barrier film 10 has excellent water vapor barrier properties and can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization. The proportion R may be 2.0% or more, 3.0% or more, or 4.0% or more. The ratio R may be less than 35.0%, 15.0% or less, 10.0% or less, or 7.0% or less. The range of the ratio R may be 2.0% to 15.0%, 2.0% to 10.0%, or 2.0% to 7.0%.

[0049] The crystallinity of the substrate 1 can be adjusted by controlling the degree of stretching of the polyethylene film used for the substrate 1 or the thermal history during or after film production. For example, the crystallinity increases when the substrate 1 is slowly cooled after formation, and decreases when it is rapidly cooled. It is also possible to improve the crystallinity of the substrate 1 by adding an additive such as a crystal nucleating agent.

[0050] The ratio R can be adjusted by the density of the polyethylene resin, the comonomer ratio, etc. For example, increasing the density of the polyethylene resin or decreasing the comonomer ratio strengthens the (200) orientation and increases the ratio R, whereas decreasing the density of the polyethylene resin or increasing the comonomer ratio weakens the (200) orientation and decreases the ratio R.

[0051] (2) Undercoat Layer The undercoat layer 9 is a layer containing an organic polymer as a main component, and is sometimes called a primer layer. The provision of the undercoat layer 9 improves the film-forming properties of the barrier layer 8, allowing for the formation of a denser inorganic layer 7 and gas barrier coating 2 with fewer defects, thereby providing the gas barrier film 10 with better water vapor barrier properties. Furthermore, the improved adhesion between the substrate 1 and the barrier layer 8 provides the gas barrier film 10 with better durability.

[0052] The content of the organic polymer in the undercoat layer 9 may be, for example, 70% by mass or more, or 80% by mass or more. Examples of organic polymers include polyacrylic resins, polyester resins, polycarbonate resins, polyurethane resins, polyamide resins, polyolefin resins, polyimide resins, melamine resins, and phenolic resins. The undercoat layer 9 preferably contains, as the organic polymer, at least one of a polyacrylic resin, a polyol resin, a polyurethane resin, a polyamide resin, or a reaction product of these organic polymers. In this case, the decrease in adhesion strength between the substrate 1 and the barrier layer 8 upon heat sterilization is suppressed, and therefore, the gas barrier film 10 can be prevented from deteriorating in durability and water vapor barrier properties even after heat sterilization. The undercoat layer 9 may contain a silane coupling agent, an organic titanate, a modified silicone oil, or the like.

[0053] The organic polymer used in the undercoat layer 9 is more preferably an organic polymer having a urethane bond formed by the reaction of a polyol having two or more hydroxyl groups at its terminal with an isocyanate compound, or an organic polymer containing a reaction product of a polyol having two or more hydroxyl groups at its terminal with an organic silane compound such as a silane coupling agent or a hydrolyzate thereof. These may be used alone or in combination of two or more.

[0054] Examples of the polyols include acrylic polyol, polyvinyl acetal, polystyrene polyol, and polyurethane polyol. The acrylic polyol may be obtained by polymerizing an acrylic acid derivative monomer, or may be obtained by copolymerizing an acrylic acid derivative monomer with another monomer. Examples of the acrylic acid derivative monomer include ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Examples of the monomer copolymerizable with the acrylic acid derivative monomer include styrene.

[0055] The isocyanate compound reacts with the polyol to form a urethane bond, thereby enhancing adhesion between the substrate 1 and the inorganic layer 7. That is, the isocyanate compound functions as a crosslinking agent or curing agent. Examples of the isocyanate compound include aromatic monomers such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), aliphatic monomers such as xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), and isophorone diisocyanate (IPDI), as well as polymers and derivatives thereof. The above-mentioned isocyanate compounds may be used alone or in combination of two or more.

[0056] Examples of silane coupling agents include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. The organic silane compound may be a hydrolysate of these silane coupling agents. The organic silane compound may contain one of the above-mentioned silane coupling agents and their hydrolysates alone, or two or more of them in combination.

[0057] The undercoat layer 9 may be formed using a mixed solution containing the above-mentioned components in any desired ratio in an organic solvent. The mixed solution may contain a curing accelerator, an antioxidant, a leveling agent, a flow control agent, a catalyst, a crosslinking accelerator, a filler, or the like. Examples of the curing accelerator include tertiary amines, imidazole derivatives, metal salt compounds of carboxylic acids, quaternary ammonium salts, and quaternary phosphonium salts. Examples of the antioxidant include phenolic antioxidants, sulfur-based antioxidants, and phosphite-based antioxidants. The mixed solution can be applied in the form of a layer on the substrate 1 using a known printing method such as offset printing, gravure printing, or silk screen printing, or a known coating method such as roll coating, knife edge coating, or gravure coating. After applying the mixed solution to the substrate 1, the undercoat layer 9 can be formed, for example, by heating the mixed solution to 50°C to 200°C.

[0058] The thickness of the undercoat layer 9 is not particularly limited and can be, for example, 0.005 μm to 5 μm. The thickness of the undercoat layer 9 can be appropriately determined depending on the application and desired properties of the laminate 30. The thickness of the undercoat layer 9 is preferably 0.01 μm to 1 μm, more preferably 0.01 μm to 0.5 μm, and even more preferably 0.01 μm to 0.1 μm. When the thickness of the undercoat layer 9 is 0.01 μm or more, sufficient adhesion strength is obtained between the substrate 1 and the barrier layer 8, and the oxygen barrier properties of the gas barrier film 10 are also good. When the thickness of the undercoat layer 9 is 1 μm or less, it is easy to form a uniform coated surface of the undercoat layer 9, and the drying load and manufacturing costs of the undercoat layer 9 can be reduced.

[0059] (3) Barrier Layer The barrier layer 8 may include either or both of the inorganic layer 7 and the gas barrier coating 2. When the barrier layer 8 includes the inorganic layer 7 and the gas barrier coating 2, the inorganic layer 7 and the gas barrier coating 2 may be laminated in this order on the first surface 1a of the substrate 1, as shown in FIG.

[0060] (Inorganic Layer) Examples of inorganic materials constituting the inorganic material layer 7 include inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, tin oxide, zinc oxide, and indium oxide, and metals such as aluminum and stainless steel. Among these, inorganic oxides are preferred as the inorganic material. In this case, the laminate 30 is superior in transparency, flex resistance, and stretch resistance compared to when the inorganic material layer 7 is a metal foil or a metal vapor deposition film. In particular, among inorganic materials, aluminum oxide or silicon oxide is excellent in productivity and can suppress deterioration of the oxygen barrier property and water vapor barrier property even when subjected to heating or moist heat treatment. The inorganic material layer 7 may be formed of one type of inorganic material, or may be formed of two or more appropriately selected inorganic materials.

[0061] The thickness of the inorganic layer 7 may be 5 nm or more. When the thickness of the inorganic layer 7 is 5 nm or more, the gas barrier film 10 has excellent oxygen barrier properties and water vapor barrier properties. The thickness of the inorganic layer 7 may be 10 nm or more, 15 nm or more, or 20 nm or more. The thickness of the inorganic layer 7 may be 200 nm or less. When the thickness of the inorganic layer 7 is 200 nm or less, the manufacturing cost of the gas barrier film 10 can be kept low, and cracks are less likely to occur in the inorganic layer 7 even after external forces such as bending or pulling are applied to the gas barrier film 10, and the gas barrier film 10 can suppress deterioration of its oxygen barrier properties and water vapor barrier properties. The thickness of the inorganic layer 7 may be 150 nm or less, 100 nm or less, 50 nm or less, or 30 nm or less. The thickness of the inorganic layer 7 may be 10 nm to 150 nm, 10 nm to 50 nm, or 10 nm to 30 nm.

[0062] The inorganic layer 7 can be formed by a known film formation method such as vacuum deposition, sputtering, ion plating, or plasma chemical vapor deposition (CVD).

[0063] (Gas barrier film) The gas barrier film 2 is a known film formed by a wet coating method. The gas barrier film 2 is obtained by forming a coating film made of a coating agent on the substrate 1 or the inorganic layer 7 by a wet coating method, and then drying this coating film. In this specification, "coating film" means a wet film, and "film" means a dry film.

[0064] The gas barrier coating 2 is preferably a coating (hereinafter sometimes referred to as an "organic-inorganic composite coating") obtained using a composition containing at least one metal alkoxide compound selected from the group consisting of a metal alkoxide, a hydrolyzate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide, and a water-soluble polymer. In this case, the gas barrier film 10 has superior oxygen barrier properties and also superior water vapor barrier properties.

[0065] Examples of the metal alkoxide contained in the composition include tetraethoxysilane [Si(OC ２ H ５ ) ４ ] and triisopropoxyaluminum [Al(OC ３ H ７ ) ３ The composition may contain only one of these compounds, or may contain an appropriate combination of two or more of these compounds.

[0066] The reaction product of a metal alkoxide refers to a product (dimer, trimer, etc.) obtained by the reaction of metal alkoxides with each other. The reaction product of a metal alkoxide hydrolysate refers to a product obtained by the reaction of a metal alkoxide with a metal alkoxide hydrolysate, or a product obtained by the reaction of metal alkoxide hydrolysates with each other.

[0067] The total content of the metal alkoxide compounds in the composition is, for example, 40% by mass to 70% by mass, based on the total amount of the composition (100% by mass). From the viewpoint of further improving the oxygen barrier property of the gas barrier film 10, the lower limit of the total content may be 50% by mass, and the upper limit of the total content may be 65% by mass.

[0068] The water-soluble polymer contained in the composition is not particularly limited, and examples thereof include various polymers such as polymers made of polysaccharides such as starch, methyl cellulose, or carboxymethyl cellulose, polyvinyl alcohol-based polymers, and acrylic polyol-based polymers. From the viewpoint of further improving the oxygen gas barrier properties of the gas barrier film 10, it is preferable that the composition contains a polyvinyl alcohol-based polymer. The number average molecular weight of the water-soluble polymer is, for example, 40,000 to 180,000.

[0069] A polyvinyl alcohol-based water-soluble polymer can be obtained, for example, by saponifying (including partial saponification) polyvinyl acetate. This water-soluble polymer may be a water-soluble polymer in which several tens of percent of acetate groups remain, or may be a water-soluble polymer in which only a few percent of acetate groups remain.

[0070] The content of the water-soluble polymer in the composition is, for example, 15% by mass to 50% by mass, preferably 20% by mass to 45% by mass. When the content of the water-soluble polymer is 20% by mass to 45% by mass, the oxygen permeability of the organic-inorganic composite film can be further reduced, and the gas barrier film 10 has better oxygen barrier properties.

[0071] The composition preferably further contains at least one silane coupling agent-based compound selected from the group consisting of a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent, in which case the gas barrier film 10 has better oxygen barrier properties.

[0072] The silane coupling agent contained in the composition includes a silane coupling agent having an organic functional group. Such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. The composition may contain only one of these, or may contain an appropriate combination of two or more.

[0073] The reaction product of a silane coupling agent refers to a product (dimer, trimer, etc.) obtained by the reaction of silane coupling agents with each other. The reaction product of a hydrolyzate of a silane coupling agent refers to a product obtained by the reaction of a silane coupling agent with a hydrolyzate of a silane coupling agent, or a product obtained by the reaction of hydrolyzates of a silane coupling agent with each other.

[0074] It is preferable to use a silane coupling agent compound having an epoxy group as the organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The silane coupling agent having an epoxy group may have an organic functional group other than the epoxy group, such as a vinyl group, an amino group, a methacryl group, or a ureyl group.

[0075] The silane coupling agent compound having an organic functional group interacts with the hydroxyl group of the water-soluble polymer, thereby improving the oxygen barrier property of the gas barrier coating 2 and providing the gas barrier film 10 with better oxygen barrier properties. Furthermore, the silane coupling agent compound having an organic functional group has better adhesion to the substrate 1 or the inorganic layer 7, providing the gas barrier film 10 with better durability. In particular, the epoxy group of the silane coupling agent compound and the hydroxyl group of the polyvinyl alcohol interact with each other to provide the gas barrier coating 2 and gas barrier film 10 with better oxygen barrier property and adhesion.

[0076] The total content of the silane coupling agent compounds in the composition is, for example, 1% by mass to 15% by mass. The total content of the silane coupling agent compounds is preferably 2% by mass to 12% by mass. In this case, the oxygen permeability of the organic-inorganic composite coating can be further reduced, and the gas barrier film 10 has even better oxygen barrier properties.

[0077] The organic-inorganic composite coating may contain a crystalline inorganic layered compound having a layered structure. Examples of inorganic layered compounds include clay minerals such as kaolinite, smectite, and mica. These may be used alone or in appropriate combinations of two or more. The inorganic layered compound has an average particle size of, for example, 0.1 μm to 10 μm. The inorganic layered compound has an average aspect ratio of, for example, 50 to 5,000.

[0078] As the inorganic layered compound, a smectite clay mineral is preferred because it can form a coating with excellent oxygen barrier properties and adhesive strength by allowing a water-soluble polymer to penetrate between the layers of the layered structure (intercalation).Specific examples of smectite clay minerals include montmorillonite, hectorite, saponite, and water-swellable synthetic mica.

[0079] Another preferred example of the gas barrier coating 2 is a coating containing a polyvalent metal salt of a polycarboxylic acid polymer (A), which is a reaction product between the carboxyl groups of the polycarboxylic acid polymer (A) and a polyvalent metal compound (B) (a polyvalent metal salt polycarboxylic acid coating). In this case, the polyvalent metal salt polycarboxylic acid coating may be a polyvalent metal salt polycarboxylic acid coating formed by applying a coating agent containing a mixture of the polycarboxylic acid polymer (A) and the polyvalent metal compound (B) and drying the mixture under heat, or may be a polyvalent metal salt polycarboxylic acid coating formed by applying a coating agent containing the polycarboxylic acid polymer (A) as the main component and drying it to form a coating A, applying a coating agent containing the polyvalent metal compound (B) as the main component and drying it to form a coating B, and then allowing a crosslinking reaction to occur between the A / B layers (i.e., between the A and B coatings). When the gas barrier coating 2 is a polyvalent metal salt polycarboxylic acid coating, the gas barrier film 10 has superior oxygen barrier properties and also superior water vapor barrier properties.

[0080] (Polycarboxylic Acid Polymer (A)) The polycarboxylic acid polymer (A) is a polymer having two or more carboxy groups in the molecule. Examples of the polycarboxylic acid polymer (A) include a polymer of an ethylenically unsaturated carboxylic acid, a copolymer of an ethylenically unsaturated carboxylic acid and another ethylenically unsaturated monomer, or an acidic polysaccharide having a carboxyl group in the molecule. Examples of the ethylenically unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated carboxylic acid include saturated carboxylic acid vinyl esters such as ethylene, propylene, and vinyl acetate, alkyl acrylates, alkyl methacrylates, alkyl itaconates, vinyl chloride, vinylidene chloride, styrene, acrylamide, and acrylonitrile. Examples of the acidic polysaccharide having a carboxyl group in the molecule include alginic acid, carboxymethyl cellulose, and pectin. These polycarboxylic acid polymers (A) may be used singly or in combination of two or more.

[0081] Among the above, from the viewpoint of the gas barrier properties of the resulting gas barrier film 10, preferred polycarboxylic acid polymers (A) are polymers containing structural units derived from at least one polymerizable monomer (ethylenically unsaturated carboxylic acid) selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, and crotonic acid, and particularly preferred are polymers containing structural units derived from at least one polymerizable monomer (ethylenically unsaturated carboxylic acid) selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid. In these polymers, the proportion of structural units derived from at least one polymerizable monomer (ethylenically unsaturated carboxylic acid) selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid is preferably 80 mol % or more, and more preferably 90 mol % or more (where the sum of all structural units constituting the polymer is taken as 100 mol %).

[0082] The polycarboxylic acid polymer (A) may be a homopolymer or a copolymer. When the polycarboxylic acid polymer (A) is a copolymer containing other structural units than the above structural units, examples of the other structural units include structural units derived from the above-mentioned ethylenically unsaturated monomers copolymerizable with the ethylenically unsaturated carboxylic acid.

[0083] The number-average molecular weight of the polycarboxylic acid polymer (A) is preferably in the range of 2,000 to 10,000,000, and more preferably 5,000 to 1,000,000. When the number-average molecular weight is 2,000 or more, the resulting gas barrier film 10 can achieve more sufficient water resistance, and deterioration of gas barrier properties and transparency due to moisture can be suppressed. Furthermore, whitening of the gas barrier film 10 does not occur. On the other hand, when the number-average molecular weight is 10,000,000 or less, the viscosity of the coating agent when forming the gas barrier film is reduced, further improving the coatability of the coating agent. The number-average molecular weight is the polystyrene-equivalent number-average molecular weight determined by gel permeation chromatography (GPC).

[0084] When a coating agent containing a polycarboxylic acid polymer (A) as a main component is applied and dried to form a coating A, and then the above-mentioned coating B is formed, some of the carboxy groups of the polycarboxylic acid polymer (A) may be neutralized in advance with a basic compound. By neutralizing some of the carboxy groups of the polycarboxylic acid polymer (A) in advance, the water resistance and heat resistance of the coating A can be further improved. The basic compound is preferably at least one basic compound selected from the group consisting of polyvalent metal compounds, monovalent metal compounds, and ammonia. As the polyvalent metal compound, compounds exemplified in the description of the polyvalent metal compound (B) below can be used. Examples of monovalent metal compounds include sodium hydroxide and potassium hydroxide.

[0085] Various additives can be added to the coating agent containing the polycarboxylic acid polymer (A) as the main component, as long as they do not impair the barrier properties of the gas barrier film 2. Examples of additives include crosslinking agents, curing agents, leveling agents, antifoaming agents, antiblocking agents, antistatic agents, dispersants, surfactants, softeners, stabilizers, film-forming agents, and thickeners.

[0086] The solvent used in the coating agent containing polycarboxylic acid polymer (A) as the main component is preferably an aqueous medium. Examples of the aqueous medium include water, water-soluble organic solvents, hydrophilic organic solvents, and mixtures thereof. The aqueous medium usually contains water or water as the main component. The water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more. Examples of the water-soluble organic solvent or hydrophilic organic solvent include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, cellosolves, carbitols, and nitriles such as acetonitrile.

[0087] (Polyvalent Metal Compound (B)) The polyvalent metal compound (B) is not particularly limited as long as it is a compound that reacts with the carboxyl groups of the polycarboxylic acid polymer (A) to form a polyvalent metal salt of a polycarboxylic acid. Examples of the polyvalent metal compound (B) include zinc oxide particles, magnesium oxide particles, magnesium methoxide, copper oxide, and calcium carbonate. These may be used alone or in combination. From the viewpoint of the oxygen barrier properties of the gas barrier coating 2, zinc oxide is preferred as the polyvalent metal compound (B).

[0088] Zinc oxide is an inorganic material capable of absorbing ultraviolet light, and there are no particular restrictions on the average particle size of the zinc oxide particles. However, from the viewpoints of the gas barrier properties and transparency of the gas barrier coating 2 and the coating suitability when forming the gas barrier coating 2, the average particle size is preferably 5 μm or less, more preferably 1 μm or less, and particularly preferably 0.1 μm or less.

[0089] When a coating agent containing a polyvalent metal compound (B) as a main component is applied and dried to form a B film, the coating agent may contain various additives in addition to zinc oxide particles, as necessary, within a range that does not impair the effects of the present disclosure. The additives may include a resin soluble or dispersible in the solvent used in the coating agent, a dispersant soluble or dispersible in the solvent, a surfactant, a softener, a stabilizer, a film-forming agent, or a thickener.

[0090] Among the above, the coating agent preferably contains a resin that is soluble or dispersible in the solvent used in the coating agent. This improves the coatability or film-forming properties of the coating agent. Examples of such resins include alkyd resins, melamine resins, acrylic resins, urethane resins, polyester resins, phenolic resins, amino resins, fluororesins, epoxy resins, and isocyanate resins.

[0091] The coating agent preferably contains a dispersant that is soluble or dispersible in the solvent used in the coating agent. This improves the dispersibility of the polyvalent metal compound (B). Anionic surfactants or nonionic surfactants can be used as the dispersant. Examples of such surfactants include (poly)carboxylates, alkyl sulfates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates, aromatic phosphate esters, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, alkyl allyl sulfate esters, polyoxyethylene alkyl phosphate esters, sorbitan alkyl esters, glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene sorbitan alkyl esters, polyoxyethylene alkyl allyl ethers, polyoxyethylene derivatives, polyoxyethylene sorbitol fatty acid esters, polyoxy fatty acid esters, and polyoxyethylene alkylamines. These surfactants may be used alone or in combination.

[0092] When an additive is contained in a coating agent containing a polyvalent metal compound (B) as a main component, the mass ratio of the polyvalent metal compound (B) to the additive (polyvalent metal compound (B):additive) is preferably within a range of 30:70 to 99:1, and more preferably within a range of 50:50 to 98:2.

[0093] Examples of solvents used in coating agents containing a polyvalent metal compound (B) as a primary component include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents may be used alone or in combination of two or more. Among these, from the viewpoint of the coatability of the coating agent, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, or water is preferred. Furthermore, from the viewpoint of the manufacturability of the gas barrier coating 2, methyl alcohol, ethyl alcohol, isopropyl alcohol, or water is preferred.

[0094] When a coating agent containing a mixture of a polycarboxylic acid polymer (A) and a polyvalent metal compound (B) is applied and dried to form a polycarboxylic acid polyvalent metal salt film, the polycarboxylic acid polyvalent metal salt film can be formed by mixing the polycarboxylic acid polymer (A), the polyvalent metal compound (B), a resin or dispersant soluble or dispersible in the solvent, and additives as needed, in water or an alcohol as a solvent, preparing a coating agent, and applying and drying it by a known coating method. Examples of coating methods include casting, dipping, roll coating, gravure coating, screen printing, reverse coating, spray coating, kit coating, die coating, metaling bar coating, chamber doctor combined coating, and curtain coating.

[0095] The thickness of the gas barrier coating 2 may be set depending on the required oxygen barrier properties and may be, for example, 0.05 μm to 5.0 μm. The thickness of the gas barrier coating 2 is preferably 0.05 μm to 1.0 μm, and more preferably 0.1 μm to 0.5 μm. If the thickness of the gas barrier coating 2 is 0.05 μm or more, sufficient oxygen barrier properties are likely to be obtained in the gas barrier film 10. If the thickness of the gas barrier coating 2 is 1.0 μm or less, it becomes easy to form a uniform coated surface when forming the gas barrier coating 2, and the drying load of the gas barrier coating 2 and the production costs of the gas barrier film 10 can be reduced.

[0096] (4) Adhesive Layer The adhesive layer 6 can be formed using, for example, a known dry laminating adhesive. Any dry laminating adhesive can be used without particular limitation, and specific examples include two-component curing ester-based adhesives, ether-based adhesives, and urethane-based adhesives.

[0097] The adhesive layer 6 may be obtained using a gas barrier adhesive that exhibits gas barrier properties after curing. By using a gas barrier adhesive, the adhesive layer 6 has gas barrier properties, and the gas barrier properties of the laminate 30 can be improved.

[0098] The oxygen permeability of the gas barrier adhesive is 150 cc / m ２ ·day·atm or less, and 100cc / m ２ ·day·atm or less is more preferable, and 80cc / m ２ It is more preferable that the viscosity is 50 cc / m or less. ２ By having an oxygen permeability within the above range, the gas barrier properties of the laminate 30 can be more sufficiently improved, and even if minor cracks or the like occur in the inorganic layer 7 or the gas barrier coating 2, the gas barrier adhesive can penetrate into the gaps, thereby preventing deterioration of the gas barrier properties of the laminate 30.

[0099] Examples of gas barrier adhesives include epoxy adhesives and polyester-polyurethane adhesives. Specific examples of gas barrier adhesives include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation.

[0100] When the adhesive layer 6 is obtained using a gas barrier adhesive, the thickness of the adhesive layer 6 is preferably at least 50 times the thickness of the inorganic layer 7. Having the thickness of the adhesive layer 6 within the above range can more sufficiently suppress cracking of the inorganic layer 7 and further improve the gas barrier properties of the laminate 30. Furthermore, having the thickness of the adhesive layer 6 within the above range can impart cushioning properties that absorb external impacts, preventing the inorganic layer 7 from cracking due to impact, thereby suppressing deterioration of the water vapor barrier properties of the laminate 30 even when subjected to impact. From the perspectives of maintaining the flexibility of the laminate 30, processability, and cost, the thickness of the adhesive layer 6 is preferably no more than 300 times the thickness of the inorganic layer 7. Specifically, the thickness of the adhesive layer 6 is, for example, 0.1 μm to 20 μm, preferably 0.5 μm to 10 μm, and more preferably 1 μm to 5 μm.

[0101] The adhesive layer 6 may be a layer obtained using a solvent-free adhesive, which is an adhesive that does not contain a solvent. In this case, since no solvent volatilizes when the adhesive layer 6 is formed, the environmental impact of the laminate 30 can be reduced. Examples of solvent-free adhesives include two-component curing urethane adhesives and one-component curing urethane adhesives. The solvent-free adhesive preferably includes a two-component curing urethane adhesive. In this case, the adhesion between the adhesive layer 6 and the barrier layer 8 or the heat seal layer 4 is improved, and the laminate 30 has sufficient durability.

[0102] When the adhesive layer 6 is obtained using a solventless adhesive, the thickness of the adhesive layer 6 is preferably at least 50 times the thickness of the inorganic layer 7. Having the thickness of the adhesive layer 6 within the above range can more sufficiently suppress cracking of the inorganic layer 7. Furthermore, having the thickness of the adhesive layer 6 within the above range can impart cushioning properties that absorb external impacts to the adhesive layer 6, preventing the inorganic layer 7 from cracking due to impact, thereby suppressing deterioration of the water vapor barrier properties of the laminate 30 even when subjected to impact. From the perspectives of maintaining the flexibility of the laminate 30, processability, and cost, the thickness of the adhesive layer 6 is preferably no more than 300 times the thickness of the inorganic layer 7. Specifically, the thickness of the adhesive layer 6 is, for example, 0.1 μm to 20 μm, preferably 0.5 μm to 10 μm, and more preferably 1 μm to 5 μm.

[0103] The adhesive layer 6 can be formed by applying an adhesive by, for example, bar coating, dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, or gravure offset. The temperature at which the adhesive coating is dried is, for example, 30°C to 200°C, and preferably 50°C to 180°C. The temperature at which the coating is cured is, for example, room temperature to 70°C, and preferably 30°C to 60°C. By keeping the drying and curing temperatures within the above ranges, the occurrence of cracks in the inorganic layer 7 and the adhesive layer 6 can be further suppressed, and the gas barrier film 10 can have excellent gas barrier properties.

[0104] The adhesive layer 6 and the inorganic layer 7 may be in direct contact with each other, or another layer such as the gas barrier coating 2 may be present between the adhesive layer 6 and the inorganic layer 7. From the viewpoint of preventing cracks from occurring in the inorganic layer 7 and the adhesive layer 6, it is preferable that the adhesive layer 6 and the inorganic layer 7 be in direct contact with each other.

[0105] (5) Heat Seal Layer The heat seal layer 4 functions as a sealant when the laminate 30 is used to produce a packaging bag or the like. The heat seal layer 4 may be a layer containing a thermoplastic resin such as polyolefin, and for example, a polyolefin film can be used as the heat seal layer 4. By including the heat seal layer 4 in the laminate 30, the laminate 30 becomes something that can be sealed by heat sealing (for example, a package or a lid).

[0106] Examples of polyolefins that can be used in the heat-seal layer 4 include polyethylenes such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer; polypropylenes such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer; and polybutene. These polyolefins can be used alone or in combination of two or more. These polyolefins can be selected appropriately depending on the intended use and temperature conditions, such as boiling treatment. The heat-seal layer 4 preferably contains polyethylene as a polyolefin. In this case, since both the substrate 1 and the heat-seal layer 4 contain polyethylene, the laminate 30 is recyclable.

[0107] If necessary, various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, or a tackifier may be added to the heat seal layer 4. The thickness of the heat seal layer 4 can be appropriately set in consideration of the shape of the packaging bag to be manufactured, the mass of the contents to be contained, and the like, and is, for example, 30 μm to 150 μm.

[0108] When the heat seal layer 4 is a polyolefin film, the heat seal layer 4 can be bonded to the gas barrier film 10 by either a dry lamination method using an adhesive such as a one-component or two-component curing urethane adhesive, or a non-solvent dry lamination method using a solvent-free adhesive. The heat seal layer 4 can also be formed by an extrusion lamination method in which a thermoplastic resin such as polyolefin is heated and melted, extruded into a curtain shape, and bonded together. In this case, the adhesive layer 6 may be omitted.

[0109] (6) Other Layers The laminate 30 may further include an easy-adhesion layer, a print layer, a protective layer, a light-shielding layer, an oxygen-absorbing layer, an adhesive layer, or other functional layers, as needed.

[0110] 1 shows a laminate 30 having a barrier layer 8 on the first surface 1a of the substrate 1 and no layer on the second surface, which is the surface opposite to the first surface 1a of the substrate 1, but the laminate of the present disclosure may further have a second adhesive layer 16 and a surface substrate layer 18, in this order, on the second surface of the substrate 1, as in the laminate 34 shown in FIG. 3. By providing these layers, the substrate 1 is reinforced by the surface substrate layer 18 via the second adhesive layer 16, and therefore the laminate 34 has better strength. The second adhesive layer 16 and the surface substrate layer 18 will be described below.

[0111] The second adhesive layer 16 is a layer that bonds the substrate 1 and the surface substrate layer 18. The adhesive layer 16 may be the same as or different from the adhesive layer 6 in terms of material, thickness, shape, etc. The second adhesive layer 16 can be formed by the same method as the adhesive layer 6.

[0112] The surface substrate layer 18 is a layer that imparts strength to the laminate 30. The surface substrate layer 18 may be the same as or different from the substrate 1 in terms of material, thickness, shape, layer configuration, etc. The surface substrate layer 18 can be formed by the same method as the substrate 1.

[0113] [Method for manufacturing laminate] (Method for manufacturing laminate 30) The laminate 30 can be manufactured by forming an inorganic layer 7 or a gas barrier coating 2 on the first surface 1a of the substrate 1, or by forming the inorganic layer 7 and the gas barrier coating 2 in this order to obtain a gas barrier film 10, and then laminating a heat seal layer 4 onto the gas barrier film 10 via an adhesive layer 6. The method for manufacturing the laminate 30 of the present disclosure includes, for example, a substrate 1 selection step, an inorganic layer formation step, a gas barrier coating formation step, and a heat seal layer lamination step.

[0114] When the manufacturing method of the laminate 30 of the present disclosure includes a step of selecting the substrate 1, it is possible to select a substrate 1 having a crystallinity (proportion of the crystalline peak area to the total peak area) of 35.0% or less, as measured by the parallel beam method of X-ray diffraction in the diffraction angle range of 10° to 30°, and having a proportion of the crystalline peak area of ​​the polyethylene (200) plane to the total peak area of ​​2.0% or more. Therefore, by including a step of selecting the substrate 1 in the manufacturing method of the laminate 30, it is possible to produce a laminate 30 that has excellent water vapor barrier properties, can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment, and has excellent adhesion between the gas barrier film 10 and the heat seal layer 4.

[0115] The step of selecting the substrate 1 may include, for example, selecting a film containing polyethylene as the main component, which has a crystallinity (proportion of the crystalline peak area to the total peak area) of 35.0% or less as measured by the parallel beam method of X-ray diffraction in the diffraction angle range of 10° to 30°, and a proportion R of the crystalline peak area of ​​the polyethylene (200) plane to the total peak area of ​​2.0% or more, as the substrate 1. The crystallinity of the substrate 1 is measured by the above-mentioned method for measuring crystallinity.

[0116] The inorganic layer forming step may include, for example, a step of forming the inorganic layer 7 on the first surface 1a side of the substrate 1 by vacuum deposition, sputtering, ion plating, plasma chemical vapor deposition (CVD), or the like.

[0117] An example of the gas barrier film formation step is a step of forming a gas barrier film 2 by applying a coating agent by a wet coating method to form a coating film and then drying the coating film (removing the solvent). Known wet coating methods can be used to apply the coating agent. Examples of wet coating methods include roll coating, gravure coating, reverse coating, die coating, screen printing, and spray coating. Known drying methods such as hot air drying, heat roll drying, and infrared irradiation can be used to dry the coating film made of the coating agent. The drying temperature for the coating film is preferably, for example, 50°C to 200°C. The drying time varies depending on the thickness of the coating film, the drying temperature, and the like, but is preferably, for example, 1 second to 5 minutes. The gas barrier film 2 may be formed by a single application and drying process, or by repeated application and drying processes using the same or different coating agents.

[0118] The heat seal layer lamination step may be, for example, a step of laminating the heat seal layer 4 on the barrier layer 8 by dry lamination using an adhesive. Examples of methods for laminating the heat seal layer 4 using an adhesive include known dry lamination and extrusion lamination methods.

[0119] (Method for manufacturing laminate 32) The laminate 32 can be manufactured by forming an undercoat layer 9 on the first surface 1a of the substrate 1, then forming an inorganic layer 7 or a gas barrier coating 2, or by forming the inorganic layer 7 and the gas barrier coating 2 in this order to obtain a gas barrier film 10, and then laminating a heat seal layer 4 onto the gas barrier film 10 via an adhesive layer 6. The method for manufacturing the laminate 32 of the present disclosure includes, for example, a substrate 1 selection step, an undercoat layer formation step, an inorganic layer formation step, a gas barrier coating formation step, and a heat seal layer lamination step, and is the same as the method for manufacturing the laminate 30 except for the undercoat layer formation step.

[0120] An example of the undercoat layer forming step is a step of applying an undercoat layer forming composition to the first surface 1 a of the substrate 1 and drying the composition to form the undercoat layer 9. The undercoat layer forming composition can be applied using a method similar to the above-described method for applying the coating agent. The undercoat layer forming composition can be dried using a method similar to the method for drying the coating film made of the above-described coating agent.

[0121] (Method for manufacturing laminate 34) The laminate 34 can be manufactured by further laminating a second adhesive layer 16 and a surface substrate layer 18 in this order on the second surface of the substrate 1 of the laminate 30. The method for manufacturing the laminate 34 of the present disclosure includes, for example, a substrate 1 selection step, an undercoat layer formation step, an inorganic layer formation step, a gas barrier coating formation step, a heat seal layer lamination step, and a surface substrate lamination step, and is the same as the method for manufacturing the laminate 30 except for the surface substrate layer lamination step.

[0122] The surface substrate layer lamination step may be, for example, a step of laminating the surface substrate layer 18 on the second surface of the substrate 1 using an adhesive by a known dry lamination method.

[0123] [Packaging] Next, an embodiment of a packaging body of the present disclosure will be described with reference to FIG. 4. FIG. 4 is a cross-sectional view schematically illustrating one embodiment of a packaging body of the present disclosure. As shown in FIG. 4, a packaging body 50 includes a packaging bag 40 and a content C accommodated in the packaging bag 40. The packaging bag 40 is formed using a laminate 30, and a heat-seal layer 4 forms the inner surface of the packaging bag 40. Specifically, the packaging bag 40 is formed by overlapping two laminates 30 with the heat-seal layers 4 facing each other and heat-sealing the peripheral edges of the heat-seal layers 4. Therefore, the packaging bag 40 includes a main body portion 41 in which the content C is accommodated and a seal portion 42 that surrounds the main body portion 41.

[0124] The packaging body 50 has excellent water vapor barrier properties in the packaging bag 40, and can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization, so that the contents C contained in the packaging bag 40 can be prevented from being exposed to water vapor and deteriorating in quality. Furthermore, the gas barrier film 10 has high adhesion to the heat seal layer 4, so the packaging body 50 has sufficient durability.

[0125] (Contents) The contents C are not particularly limited, but examples of the contents C include food, medicine, etc. When the contents C are food, the packaging body 50 can suppress deterioration of the water vapor barrier property even when subjected to heat sterilization treatment.

[0126] (Packaging Bag) In this embodiment, the packaging bag 40 includes a main body 41 containing the contents C and seal portions 42 surrounding the four peripheral edges of the main body 41. That is, the packaging bag 40 is configured as a four-sided pouch. The two laminates 30 constituting the packaging bag 40 may be identical to or different from each other. That is, the layers constituting the laminate 30 may be identical to or different from each other in terms of material, thickness, shape, etc. The packaging bag 40 is not particularly limited to a four-sided pouch and can be appropriately selected depending on the intended use of the packaging bag. The packaging bag 40 may be, for example, a three-sided pouch, a pillow bag, a stand-up pouch, a gusset bag, a bag with a spout, etc. Note that the packaging bag 40 may be configured from three or more laminates 30. In this case, the multiple laminates 30 constituting the packaging bag 40 may be made of different materials and may have different thicknesses, shapes, etc.

[0127] Examples of heat sterilization treatment include moist heat treatment such as retort treatment and boiling treatment.

[0128] In this embodiment, the laminate 30 is used as the laminate that constitutes the packaging body and the packaging bag, but the laminate 32 or the laminate 34 may be used instead of the laminate 30 .

[0129] The present disclosure will be described in more detail below with reference to examples and comparative examples, although the present disclosure is not limited to the following examples.

[0130] The materials used in each example and comparative example are as follows: <Materials used> (Resin films α1 to α6) Resin film α1: Unstretched polyethylene film (thickness 25 μm, density 0.952 g / cm ３ ), one side corona treated. Resin film α2: unstretched polyethylene film (thickness 25 μm, density 0.950 g / cm ３ ), one side corona treated. Resin film α3: unstretched polyethylene film (thickness 40 μm, density 0.949 g / cm ３ ), one side corona treated. Resin film α4: unstretched polyethylene film (thickness 30 μm, density 0.947 g / cm ３ , one side corona treated. Resin film α5: uniaxially oriented polyethylene film (thickness 25 μm, density 0.950 g / cm ３ ), one side corona treated. Resin film α6: biaxially oriented polyethylene film (thickness 25 μm, density 0.95 g / cm ３ ), one side corona treated.

[0131] (Polyethylene) Resin A: Density 0.941 g / cm ３ , MFR1.3g / 10min. ・Resin B: Density 0.962g / cm ３ , MFR0.85g / 10min. ・Resin C: Density 0.971g / cm ３ , MFR1.2g / 10min. ・Resin D: Density 0.967g / cm ３ , MFR1.2g / 10min. ・Resin E: Density 0.960g / cm ３ , MFR1.0g / 10min. ・Resin F: Density 0.963g / cm ３ , MFR1.4g / 10min.

[0132] (Resin films α7 to α15) Resins A to F shown in Table 1 below were charged into an extruder as resins for forming the surface layer, intermediate layer, and back layer, respectively, and melt-kneaded at 190°C. After that, polyethylene was discharged from a three-layer die, and resin films (multilayer polyethylene films) α7 to α15 were produced by the air-cooled inflation method. As shown in Table 1, the thicknesses of the resin films α7 to α15 were all 30 μm. The layer thickness ratios of the surface layer, intermediate layer, and back layer and the densities of the resin films α7 to α15 were also shown in Table 1.

[0133] (Mixed Solution for Forming Undercoat Layer) The following acrylic polyol and isocyanate compound were mixed together to give a solids mass ratio of 6:4 to obtain a mixture. Then, the mixture was diluted by adding ethyl acetate to give a solids concentration of 2 mass %. In this way, a mixed solution for forming an undercoat layer was obtained. Acrylic polyol: Acrydic CL-1000 (trade name), manufactured by DIC Corporation Isocyanate compound: TDI type curing agent Coronate 2030 (trade name), manufactured by Tosoh Corporation

[0134] (Mixed Solution for Forming Organic-Inorganic Composite Coating) An aqueous solution of the following polyvinyl alcohol resin (PVA, Poval PVA-105 (product name), manufactured by Kuraray Co., Ltd., saponification degree 98% to 99%, polymerization degree 500), tetraethoxysilane (TEOS), and γ-glycidoxypropyltrimethoxysilane (GPTMS, KBM-403 (product name), manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent was hydrolyzed with 0.02 mol / L hydrochloric acid to prepare three aqueous solutions, and the three aqueous solutions were mixed so that the mass ratio of PVA:TEOS:GPTMS before hydrolysis was 40:50:10. Furthermore, the aqueous solution obtained by mixing was diluted with a solvent (isopropyl alcohol) so that the mass ratio of water to isopropyl alcohol in the solvent components was 90:10. In this way, a mixed solution for forming an organic-inorganic composite coating (solids concentration 5% by mass) was obtained.

[0135] (A coating mixture) 20 parts by mass of the following polyacrylic acid aqueous solution was diluted by adding 58.9 parts by mass of distilled water to obtain a diluted solution. Then, 0.44 parts by mass of the following silane coupling agent was added to the diluted solution, and the mixture was stirred to obtain a uniform solution. In this way, an A coating mixture containing a polycarboxylic acid polymer as the main component was obtained. Polyacrylic acid aqueous solution: Aron A-10H (product name), manufactured by Toagosei Co., Ltd., number average molecular weight 200,000, solid content concentration 25% by mass Silane coupling agent: aminopropyltrimethoxysilane (APTMS), manufactured by Aldrich

[0136] (Mixed Solution for Coating B) 100 parts by mass of the following zinc oxide microparticle aqueous dispersion and 2 parts by mass of the following curing agent were mixed to obtain a mixed solution for coating B containing a polyvalent metal compound as the main component. Zinc oxide microparticle aqueous dispersion: ZE143 (product name), manufactured by Sumitomo Osaka Cement Co., Ltd. Curing agent: Liofol HAERTER UR 5889-21 (product name), manufactured by Henkel

[0137] (Urethane-based adhesive) 100 parts by mass of Takelac A525 (product name, manufactured by Mitsui Chemicals, Inc.), 11 parts by mass of Takenate A52 (product name, manufactured by Mitsui Chemicals, Inc.), and 84 parts by mass of ethyl acetate were mixed to obtain a urethane-based adhesive.

[0138] (Gas barrier adhesive) 23 parts by mass of a solvent obtained by mixing ethyl acetate and methanol in a mass ratio of 1:1 was mixed with 16 parts by mass of Maxieve C93T (product name, manufactured by Mitsubishi Gas Chemical Company, Inc.) and 5 parts by mass of Maxieve M-100 (product name, manufactured by Mitsubishi Gas Chemical Company, Inc.) to obtain a gas barrier adhesive.

[0139] (Solvent-free adhesive) 70 parts by mass of LOCTITE (registered trademark) LIOFOL LA7735 (product name, Henkel Japan Co., Ltd.) and 30 parts by mass of LOCTITE LIOFOL LA6195 (product name, Henkel Japan Co., Ltd.) were mixed to obtain a solvent-free adhesive.

[0140] <Preparation of Laminate> (Example 1) A coating film was formed by applying a liquid mixture for forming an undercoat layer to the corona-treated surface of a resin film α1 using a gravure printing machine, and the coated resin film was passed through an oven at 60°C for 10 seconds to dry, thereby forming an undercoat layer having a thickness of 0.1 µm on the resin film α1. Next, a 30 nm-thick inorganic layer made of silicon oxide was formed on the undercoat layer using a vacuum deposition apparatus employing an electron beam heating method. A mixed material containing two or more of metallic silicon, silicon monoxide, and silicon dioxide was used as the deposition material. Furthermore, the mixed liquid for the organic / inorganic composite coating (solid content concentration: 5% by mass) was applied onto the inorganic layer using a gravure printing machine to form a coating, and the coating was dried by passing it through an oven at 60°C for 10 seconds to form a gas barrier coating consisting of an organic / inorganic composite coating having a thickness of 0.3 μm. In this way, a gas barrier film was obtained. Finally, a 60 μm-thick film for the heat seal layer described below was dry-laminated onto the gas barrier coating of the gas barrier film using a multi-coater (product name: TM-MC, manufactured by Hirano Tecseed Co., Ltd.) via an adhesive, and the film was cured at 40°C for 3 days. In this way, a laminate according to Example 1 was obtained. The urethane-based adhesive was used as the adhesive. Film for the heat seal layer: linear low-density polyethylene (LLDPE) film, TUX MC-S (product name), manufactured by Mitsui Chemicals Tohcello, Inc.

[0141] (Examples 2, 6, 7, 11 to 16, Comparative Examples 1, 2, 6, 7, 11 to 13) Laminates according to Examples 2, 6, 7, 11 to 16 and Comparative Examples 1, 2, 6, 7, 11 to 13 were obtained in the same manner as in Example 1, except that the resin films and adhesives shown in Tables 2 to 4 were used.

[0142] Example 3 A laminate according to Example 3 was obtained in the same manner as in Example 1, except that no undercoat layer was formed.

[0143] Example 4 A laminate according to Example 4 was obtained in the same manner as in Example 1, except that a 20 nm-thick inorganic layer made of aluminum oxide was formed as the inorganic layer, and a gas barrier coating made of a polyvalent metal salt film was formed as the gas barrier coating by the following method. (Formation of Polyvalent Metal Salt Film) First, a coating A mixture was applied to the inorganic layer using a gravure printer to form a coating, and the coating was dried in an oven at 60°C for 10 seconds to form a 0.2 μm-thick A coating. Next, a coating B mixture was applied to the inorganic layer using a gravure printer to form a coating, and the coating was dried in an oven at 60°C for 10 seconds to form a 0.2 μm-thick B coating. In this way, a gas barrier coating made of a polyvalent metal salt film of a polycarboxylic acid was formed.

[0144] Example 5, Comparative Examples 3, 4 and 8 Laminates according to Example 5 and Comparative Examples 3, 4 and 8 were obtained in the same manner as in Example 4, except that the resin films shown in Table 2 or 3 were used as the resin films.

[0145] Example 8 A laminate according to Example 8 was obtained in the same manner as in Example 6, except that no gas barrier film was formed.

[0146] Example 9 A laminate according to Example 9 was obtained in the same manner as in Example 1, except that no gas barrier film was formed.

[0147] Example 10 A laminate according to Example 10 was obtained in the same manner as in Example 4, except that no gas barrier film was formed and the gas barrier adhesive was used as the adhesive.

[0148] (Example 17) A laminate according to Example 17 was obtained in the same manner as in Example 1, except that the above-mentioned solvent-free adhesive was used as the adhesive and the amount of adhesive applied was such that the thickness of the adhesive layer after drying was 2 μm.

[0149] (Example 18) A laminate according to Example 18 was obtained in the same manner as in Example 4, except that the above-mentioned solventless adhesive was used as the adhesive and the amount of adhesive applied was such that the thickness of the adhesive layer after drying was 2 μm.

[0150] (Example 19) A laminate according to Example 19 was obtained in the same manner as in Example 8, except that the solvent-free adhesive was used as the adhesive and the amount of adhesive applied was such that the thickness of the adhesive layer after drying was 2 μm.

[0151] Comparative Examples 5, 9, and 10 Laminates according to Comparative Examples 5, 9, and 10 were obtained in the same manner as in Example 8, except that the resin films shown in Table 3 were used as the resin films.

[0152] <Determination of the Crystallinity of the Substrate and the Ratio R of the Crystalline Peak Area of ​​the (200) Plane of Polyethylene to the Total Peak Area> Prior to the preparation of the laminate, the crystallinity of the resin film serving as the substrate and the ratio R of the crystalline peak area of ​​the (200) plane of polyethylene to the total peak area were determined using the parallel beam method of X-ray diffraction. Specifically, 10 mm x 50 mm films were first cut out from resin films α1 to α15 to obtain measurement samples. Next, the measurement samples were placed on the sample stage of a wide-angle X-ray diffractometer (product name: ATX-G, manufactured by Rigaku Corporation). Next, out-of-plane measurement was performed under the following measurement conditions, and an X-ray diffraction pattern was obtained by 2θ / θ scanning over a diffraction angle range of 10° to 30°. X-rays were made using characteristic CuKα X-rays, which were collimated by a multilayer mirror and incident, and a scintillation detector equipped with a flat collimator was used as the light-receiving unit. The measurement conditions were as follows: (Measurement conditions) Attenuator: 1 / 800 Step width: 0.02° Scan speed: 2.0° / min Finally, separation analysis was performed on the obtained X-ray diffraction pattern to determine each crystalline peak area S1 and the halo pattern area S2 derived from amorphous components. The sum of these areas, S (= S1 + S2), was defined as the total peak area, and the crystallinity of the substrate was calculated based on the following formula (1). The results are shown in Tables 2 to 4. Crystallinity (%) = 100 × S1 / S (= S1 + S2) (1) Furthermore, the crystalline peak area S3 corresponding to the (200) plane of polyethylene was determined from the X-ray diffraction pattern obtained as described above. Then, the proportion R of the crystalline peak area S3 of the (200) plane of polyethylene to the total peak area S was calculated based on the following formula (2). R (%) = 100 × S3 / S (= S1 + S2) (2) In this way, the crystallinity of the substrate and the ratio R of the crystalline peak area of ​​the (200) plane of polyethylene to the total peak area were determined. The results are shown in Tables 2 to 4.

[0153] (1) Water Vapor Permeability (Water Vapor Permeability Before Boiling Treatment) The water vapor permeability of the laminates according to each Example and Comparative Example was measured under the following conditions in accordance with JIS K-7126, Method B. The results are shown in Tables 5 to 7 as the water vapor permeability before boiling treatment. (Measurement Conditions) Measuring Device: PERMATRAN-W 3 / 34G (product name), manufactured by MOCON Corporation Measuring Atmosphere: 40°C, 90% RH (Water Vapor Permeability After Boiling Treatment) First, two A5-sized samples were cut out from the laminates according to each Example and Comparative Example and stacked with the heat-sealed layer facing inward. Only three sides of the stacked two laminates were heat-sealed, leaving the remaining side unsealed, to form a pouch with an opening. Next, 150 ml of tap water was filled into the prepared pouch through the opening, and the remaining side was heat-sealed to form a four-sided sealed pouch. Next, the four-side sealed pouches were subjected to a boiling treatment (heat sterilization treatment) in hot water at 90°C for 30 minutes. Finally, a portion of the four-side sealed pouch after the boiling treatment was cut out and thoroughly dried to obtain a laminate after the boiling treatment. The water vapor permeability of the laminate after the boiling treatment was then measured in the same manner as before the boiling treatment. The results are shown in Tables 5 to 7.

[0154] (2) Oxygen Permeability (Oxygen Permeability Before Boiling Treatment) The oxygen permeability of the laminates according to each Example and Comparative Example was measured under the following conditions in accordance with JIS K-7126, Method B. The results are shown in Tables 5 to 7 as the oxygen permeability before boiling treatment. (Measurement Conditions) Measuring device: OXTRAN-2 / 22 (product name), manufactured by MOCON Corporation Measuring atmosphere: 30°C, 70% RH (Oxygen Permeability After Boiling Treatment) Four-sided sealed pouches were prepared in the same manner as in (1) above, and the prepared four-sided sealed pouches were subjected to a boiling treatment (heat sterilization treatment) in hot water at 90°C for 30 minutes. Next, a portion of the four-sided sealed pouch after boiling treatment was cut out and thoroughly dried to obtain a laminate after boiling treatment. The oxygen permeability of the laminate after boiling treatment was then measured in the same manner as before boiling treatment. The results are shown in Tables 5 to 7.

[0155] (3) Adhesion: Four-sided sealed pouches were prepared in the same manner as in (1) above, and the prepared four-sided sealed pouches were subjected to a boiling treatment (heat sterilization treatment) in hot water at 90°C for 30 minutes. Next, a portion was cut from the boiled four-sided sealed pouch and thoroughly dried to obtain a strip-shaped test piece measuring 15 mm in width and 100 mm in length. This test piece was then subjected to a T-peel test using an Orientec Tensilon universal testing machine RTC-1250. The T-peel test was conducted in accordance with JIS K 6854-3 under the following test conditions, in which the gas barrier film and the heat seal layer were peeled apart. The tensile strength at which the gas barrier film and the heat seal layer separated was taken as the adhesion strength of the laminate. The results are shown in Tables 5 to 7. This adhesion strength serves as an indicator of the adhesion between the gas barrier film and the heat seal layer. (Test conditions) Chuck distance: 15 mm Pulling speed: 300 mm / min

[0156]

[0157]

[0158]

[0159]

[0160]

[0161]

[0162] From the results shown in Tables 5 to 7, in Examples 1 to 19, the water vapor permeability before the boiling treatment was 2.0 g / (m ２ ·day) or less, and the difference in water vapor permeability before and after the boiling treatment is 1.0 g / (m ２ ·day) or less, which was sufficiently small. In addition, in Examples 1 to 19, the adhesion strength after boiling was 5.0 N / 15 mm or more, which was a sufficiently large value. On the other hand, in Comparative Examples 1 to 5 and 11 to 13, in which the proportion of the crystalline peak area of ​​the (200) plane of polyethylene to the total peak area of ​​the substrate was less than 2.0%, the difference in water vapor permeability before and after boiling was 1.4 g / (m ２In Comparative Examples 6 to 10, in which the crystallinity of the substrate was greater than 35.0%, the difference in water vapor permeability before and after the boiling treatment was 2.0 g / (m ２ The water vapor permeability was significantly different before and after the boiling treatment. The adhesion strength was less than 5.0 N / 15 mm, which was a very small value.

[0163] From the above, it was confirmed that the gas barrier film of the present disclosure has excellent water vapor barrier properties, can suppress deterioration of the water vapor barrier properties even when subjected to heat sterilization treatment, and has high adhesion to the heat seal layer.

[0164] The present disclosure is outlined as follows: [1] A gas barrier film comprising: a substrate containing polyethylene; and a barrier layer formed on one side of the substrate, wherein the barrier layer comprises at least one of an inorganic layer and a gas barrier coating, wherein the substrate has a crystallinity of 35.0% or less, which is the ratio of the crystalline peak area to the total peak area in the diffraction angle range of 10° to 30° in an X-ray diffraction pattern obtained by measuring the substrate using a parallel beam X-ray diffraction method, and wherein the ratio of the crystalline peak area of ​​the (200) plane of polyethylene to the total peak area is 2.0% or more. [2] A gas barrier film comprising: a substrate containing polyethylene; and a barrier layer formed on one side of the substrate, wherein the barrier layer comprises at least one of an inorganic layer and a gas barrier coating, wherein the substrate has a crystallinity of 35.0% or less, which is the ratio of the crystalline peak area to the total peak area in the diffraction angle range of 10° to 30° in an X-ray diffraction pattern obtained by measuring the substrate using a parallel beam X-ray diffraction method, and wherein the ratio of the crystalline peak area of ​​the (200) plane of polyethylene to the total peak area is 2.0% or more. ３The gas barrier film according to [1], wherein the substrate is an unstretched film. [3] The gas barrier film according to [1] or [2], wherein the substrate is an unstretched film. [4] The gas barrier film according to any one of [1] to [3], wherein the inorganic layer is made of aluminum oxide or silicon oxide. [5] The gas barrier film according to any one of [1] to [4], wherein the gas barrier coating is obtained using a composition containing at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolysate of a metal alkoxide, and a water-soluble polymer. [6] The gas barrier film according to [5], wherein the composition further contains at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolysate of a silane coupling agent. [7] The gas barrier film according to any one of [1] to [4], wherein the gas barrier coating contains a polyvalent metal salt of a polycarboxylic acid polymer. [8] The gas barrier film according to any one of [1] to [7], wherein the substrate is a multilayer polyethylene film having a surface layer, an intermediate layer, and a back layer, and the multilayer polyethylene film is formed by feeding the polyethylenes forming the surface layer, the intermediate layer, and the back layer into extruders, respectively, melt-kneading the polyethylene, and then discharging the polyethylene from the extruder through a die, using an inflation method. [9] A laminate comprising the gas barrier film according to any one of [1] to [8], and a heat seal layer bonded to the gas barrier film so as to sandwich the barrier layer between the substrate and the gas barrier film.

[10] The laminate according to [9], wherein the heat seal layer contains polyethylene.

[11] The laminate according to [9] or

[10] , further comprising an adhesive layer bonding the gas barrier film and the heat seal layer.

[12] The laminate according to

[11] , wherein the adhesive layer is obtained using a gas barrier adhesive.

[13] The laminate according to

[11] , wherein the adhesive layer is obtained using a solventless adhesive.

[14] The laminate according to

[13] , wherein the solvent-free adhesive comprises a two-component curing urethane adhesive.

[15] The laminate according to any one of [9] to

[15] , further comprising a second adhesive layer and a surface substrate layer, in this order, on a substrate on the surface opposite the heat seal layer of the laminate.

[16] A packaging bag formed using the laminate according to any one of [8] to

[15] .

[17] A packaging body comprising the packaging bag according to

[16] and contents accommodated in the packaging bag.

[18] An adhesive layer is further provided between the barrier layer and the heat seal layer, and an undercoat layer is further provided between the substrate and the barrier layer, the barrier layer having, from the undercoat layer side, an inorganic layer and a gas barrier film in this order, the adhesive layer is a layer that bonds the gas barrier film and the heat seal layer, the substrate is a non-stretched film consisting of a surface layer, an intermediate layer and a back layer, the density of the substrate is 0.940 g / cm3 or more, the thickness of the substrate is 15 μm to 35 μm, the surface layer and the back layer have the same thickness, the ratio of the thickness of the intermediate layer to the thickness of the surface layer is 2 to 3, the inorganic layer is made of silicon oxide, the thickness of the undercoat layer is 0.01 μm to 0.1 μm, and the thickness of the inorganic layer is 10 nm to 30 nm, the gas barrier coating is a coating obtained using a composition containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide, and a water-soluble polymer; the heat seal layer is a layer made of linear low-density polyethylene; the adhesive layer is a layer obtained using a solventless adhesive; the X-ray diffraction pattern is an X-ray diffraction pattern obtained by out-of-plane measurement using a wide-angle X-ray diffractometer to perform 2θ / θ scanning over a diffraction angle range of 10° to 30°; and the crystallinity is a value calculated by the following formula (1) and the ratio is a ratio calculated by the following formula (2), where S1 is the area of ​​the crystalline peak obtained by separating and analyzing a crystalline peak derived from a crystalline component and a halo pattern derived from an amorphous component in the X-ray diffraction pattern, S2 is the area of ​​the halo pattern, and S3 is the area of ​​the crystalline peak corresponding to the (200) plane of polyethylene obtained by separating and analyzing peaks corresponding to the (110) plane and the (200) plane of polyethylene from the crystalline peak: The laminate according to any one of [9],

[14] , and

[15] , wherein the crystallinity is 15.0% to 35.0%, and the ratio is 2.0% to 7.0%, where: Crystallinity (%) = 100 × S1 / (S1 + S2) (1) Ratio (%) = 100 × S3 / (S1 + S2) (2).

[0165] The gas barrier film of the present disclosure has excellent water vapor barrier properties, can suppress deterioration of water vapor barrier properties even when subjected to heat sterilization treatment, and has high adhesion to the heat seal layer. Therefore, a laminate including the gas barrier film of the present disclosure can be suitably used as a variety of packaging materials, particularly suitable for packaging materials that undergo boiling treatment, and a package including this laminate can maintain the quality of the contents for a long period of time. The laminate and gas barrier film of the present disclosure can also be used for applications other than packaging materials. Examples of applications other than packaging materials include electronic device-related films, solar cell films, various functional films for fuel cells, substrate films, etc.

[0166] DESCRIPTION OF SYMBOLS 1...substrate, 2...gas barrier coating, 4...heat seal layer, 6...adhesive layer, 7...inorganic layer, 8...barrier layer, 9...undercoat layer, 10...gas barrier film, 12...surface layer, 13...intermediate layer, 14...back layer, 16...second adhesive layer, 18...surface substrate layer, 30, 32, 34...laminate, 40...packaging bag, C...contents, 50...packaging

Claims

1. A gas barrier film comprising: a substrate containing polyethylene; and a barrier layer formed on one side of the substrate, the barrier layer including at least one of an inorganic layer and a gas barrier coating, and in an X-ray diffraction pattern obtained by measuring the substrate using a parallel beam X-ray diffraction method, the substrate has a crystallinity of 35.0% or less, which is the ratio of the crystalline peak area to the total peak area in the diffraction angle range of 10° to 30°, and the ratio of the crystalline peak area of ​​the (200) plane of polyethylene to the total peak area is 2.0% or more.

2. The density of the polyethylene is 0.940 g / cm ３ The gas barrier film according to claim 1 .

3. The gas barrier film according to claim 1, wherein the substrate is a non-oriented film.

4. The gas barrier film according to claim 1, wherein the inorganic layer comprises aluminum oxide or silicon oxide.

5. The gas barrier film according to claim 1, wherein the gas barrier coating is a coating obtained using a composition containing at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolysate of a metal alkoxide, and a water-soluble polymer.

6. The gas barrier film of claim 5, wherein the composition further comprises at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolysate of a silane coupling agent.

7. The gas barrier film according to claim 1, wherein the gas barrier coating contains a polyvalent metal salt of a polycarboxylic acid polymer.

8. The gas barrier film according to claim 1, wherein the substrate is a multilayer polyethylene film having a surface layer, an intermediate layer and a back layer, and the multilayer polyethylene film is formed by feeding the polyethylene forming the surface layer, the intermediate layer and the back layer into an extruder, respectively, melt-kneading the polyethylene, and then discharging it from the extruder through a die, and extruding the multilayer polyethylene film by an inflation method.

9. A laminate comprising the gas barrier film according to any one of claims 1 to 8 and a heat seal layer joined to the gas barrier film so as to sandwich the barrier layer between the gas barrier film and the substrate.

10. The laminate of claim 9, wherein said heat seal layer comprises polyethylene.

11. The laminate according to claim 9, further comprising an adhesive layer that bonds said gas barrier film and said heat seal layer.

12. The laminate according to claim 11, wherein the adhesive layer is obtained by using a gas barrier adhesive.

13. The laminate according to claim 11, wherein the adhesive layer is obtained using a solvent-free adhesive.

14. The laminate according to claim 13, wherein the solvent-free adhesive comprises a two-component curing urethane adhesive.

15. The laminate of claim 9, further comprising a second adhesive layer and a surface substrate layer, in that order, on a substrate opposite the heat seal layer of the laminate.

16. A packaging bag formed using the laminate according to claim 9.

17. A package comprising the packaging bag according to claim 16 and contents contained within the packaging bag.

18. A method for producing a laminated laminated laminate comprising the steps of: further comprising: providing an adhesive layer between the barrier layer and the heat seal layer; further comprising: providing an undercoat layer between the substrate and the barrier layer; the barrier layer having, from the undercoat layer side, an inorganic layer and a gas barrier film in this order; the adhesive layer being a layer for bonding the gas barrier film and the heat seal layer; the substrate being a non-oriented film consisting of a surface layer, an intermediate layer and a back layer; and the density of the substrate being 0.940 g / cm. ３ or more, the thickness of the substrate is 15 μm to 35 μm, the thickness of the surface layer and the thickness of the back layer are the same, the ratio of the thickness of the intermediate layer to the thickness of the surface layer is 2 to 3, the inorganic layer is made of silicon oxide, the thickness of the undercoat layer is 0.01 μm to 0.1 μm, the thickness of the inorganic layer is 10 nm to 30 nm, the gas barrier coating is a coating obtained using a composition containing at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolysate of a metal alkoxide, and a water-soluble polymer, the heat seal layer is a layer made of linear low density polyethylene, the adhesive layer is a layer obtained using a solventless adhesive, and the X-ray diffraction pattern is an X-ray diffraction pattern obtained by out-of-plane measurement using a wide-angle X-ray diffractometer to perform 2θ / θ scanning in the diffraction angle range of 10° to 30°, 10. The laminate according to claim 9, wherein the area of ​​a crystalline peak obtained by separating and analyzing a crystalline peak derived from a crystalline component and a halo pattern derived from an amorphous component in the X-ray diffraction pattern is S1, the area of ​​the halo pattern is S2, and the area of ​​a crystalline peak corresponding to the (200) plane of polyethylene obtained by separating and analyzing peaks corresponding to the (110) plane and the (200) plane of polyethylene for the crystalline peak is S3, the crystallinity is a value calculated by the following formula (1) and the ratio is a ratio calculated by the following formula (2), the crystallinity is 15.0% to 35.0%, and the ratio is 2.0% to 7.0%. Crystallinity (%)=100×S1 / (S1+S2) (1) Ratio (%)=100×S3 / (S1+S2) (2)

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