Gas barrier laminate and packaging bag

Abstract

This gas-barrier layered body is provided with, in order: a paper substrate; an anchor coating layer containing a first polyolefin having polar groups; an evaporated layer; and an overcoating layer containing a second polyolefin having polar groups.

Description

[Technical Field]

[0001] The present invention relates to a gas barrier laminate and a packaging bag. [Background technology]

[0002] Packaging materials are used in many fields, including food, beverages, pharmaceuticals, and chemicals, depending on the contents. Packaging materials are required to have gas barrier properties that prevent the permeation of oxygen and water vapor, which can cause deterioration of the contents.

[0003] In recent years, growing environmental awareness stemming from the problem of marine plastic waste and other issues has led to a growing trend toward a plastic-free society. From the perspective of reducing the amount of plastic material used, the use of paper instead of plastic materials has been considered in various fields. For example, Patent Document 1 listed below discloses a gas barrier laminate in which a barrier layer is laminated on paper. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-69783 Summary of the Invention [Problem to be solved by the invention]

[0005] Paper has the advantage of being easy to process due to its fold retention (also known as deadhold property). However, the inventors' investigations have revealed that there is still room for improvement in that cracks occur in the barrier layer and the gas barrier properties deteriorate when paper is used to make packaging bags with sharper folds (pillow packaging, three-side seal packaging, and gusset packaging).

[0006] Furthermore, from the perspective of the Law for Promoting Effective Utilization of Resources, it is required to reduce the amount of plastic materials used in gas barrier laminates as well.

[0007] The present invention has been made in view of the above-mentioned circumstances, and aims to provide a gas barrier laminate that has the fold retention characteristic of paper, has sufficient gas barrier properties even after being folded, and contributes to reducing the amount of plastic material used, as well as a packaging bag including the gas barrier laminate. [Means for solving the problem]

[0008] The present invention provides a gas barrier laminate comprising, in this order: a paper substrate; an anchor coat layer containing a first polyolefin having a polar group; a vapor deposition layer; and an overcoat layer containing a second polyolefin having a polar group.

[0009] The first polyolefin having a polar group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0010] The second polyolefin having a polar group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0011] The first polyolefin having a polar group may be a copolymer of an acrylic acid ester and maleic anhydride.

[0012] The first polyolefin having a polar group may be an ethylene-vinyl acetate copolymer.

[0013] The first polyolefin having a polar group may be an ethylene-glycidyl methacrylate copolymer.

[0014] The second polyolefin having a polar group may be a copolymer of an acrylic acid ester and maleic anhydride.

[0015] The second polyolefin having a polar group may be an ethylene-vinyl acetate copolymer.

[0016] The second polyolefin having a polar group may be an ethylene-glycidyl methacrylate copolymer.

[0017] The thickness of the anchor coat layer may be 1 μm or more.

[0018] The weight of the paper may be 50% by mass or more based on the weight of the entire gas barrier laminate.

[0019] The present invention also provides a packaging bag comprising the gas barrier laminate according to the present invention.

[0020] The packaging bag may have a fold. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a gas barrier laminate and a packaging bag including the same, which have the fold retention properties that are characteristic of paper and have sufficient gas barrier properties even after being folded, and which contribute to reducing the amount of plastic material used. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic cross-sectional view showing a gas barrier laminate according to one embodiment of the present invention. [Figure 2] 1 is a perspective view showing a packaging bag according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings where necessary, but the present invention is not limited to the following embodiments.

[0024] <Gas barrier laminate> 1 is a schematic cross-sectional view showing a gas barrier laminate according to one embodiment. The gas barrier laminate 10 according to one embodiment comprises, in this order, a paper substrate 1, an anchor coat layer 2, a vapor-deposited layer 3, and an overcoat layer 4. The anchor coat layer 2 contains a first polyolefin having a polar group, and the overcoat layer 4 contains a second polyolefin having a polar group.

[0025] [Paper base material] The paper substrate 1 is not particularly limited, and may be appropriately selected depending on the application of the packaging bag to which the gas barrier laminate 10 is applied. There are no particular limitations on the paper as long as it is made primarily of plant-derived pulp. Specific examples of the paper substrate 1 include fine paper, special fine paper, coated paper, art paper, cast-coated paper, construction paper, kraft paper, and glassine paper. The thickness of the paper substrate 1 is, for example, 20 to 500 g / m 2 , 30~100g / m 2 It may be.

[0026] The paper substrate 1 may have a coating layer at least on the side that contacts the anchor coat layer 2 described below. The coating layer prevents the anchor coat layer from penetrating into the paper and also acts as a sealant, filling in any irregularities in the paper, allowing the anchor coat layer to be formed uniformly and without defects. The coating layer may contain, for example, various copolymers such as styrene-butadiene, styrene-acrylic, and ethylene-vinyl acetate copolymers, polyvinyl alcohol resins, cellulose resins, and paraffin (wax) as binder resins, and may also contain fillers such as clay, kaolin, calcium carbonate, talc, and mica.

[0027] The thickness of the coating layer is not particularly limited, but may be, for example, 1 to 10 μm, or 3 to 8 μm.

[0028] The weight of paper is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the weight of the entire gas barrier laminate. If the weight of paper is 50% by mass or more, based on the weight of the entire gas barrier laminate, the amount of plastic material used can be sufficiently reduced, the gas barrier laminate as a whole can be said to be made of paper, and recyclability is excellent.

[0029] [Anchor coat layer] The anchor coat layer 2 is provided on the surface of the paper substrate to improve adhesion between the paper substrate 1 and the vapor deposition layer 3 described below, and to improve the gas barrier properties of the gas barrier laminate. The anchor coat layer 2 contains a first polyolefin having polar groups. Such an anchor coat layer 2 has excellent flexibility and can suppress cracking of the vapor deposition layer described below after bending (folding), while also improving adhesion between the anchor coat layer and the vapor deposition layer. Furthermore, the inclusion of a polyolefin having polar groups makes it possible to form a dense film due to the crystallinity of the polyolefin, and water vapor barrier properties are exhibited. The crystallinity of the polyolefin exhibits water vapor barrier properties, and the presence of polar groups exhibits adhesion to the vapor deposition layer.

[0030] The first polyolefin having a polar group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0031] The first polyolefin having a polar group may be a copolymer of ethylene or propylene with an unsaturated carboxylic acid (an unsaturated compound having a carboxyl group, such as acrylic acid, methacrylic acid, or maleic anhydride), an unsaturated carboxylic acid ester, or a salt of a carboxylic acid neutralized with a basic compound. Alternatively, a copolymer of ethylene or propylene with vinyl acetate, an epoxy compound, a chlorine compound, a urethane compound, or a polyamide compound may be used.

[0032] Specific examples of the first polyolefin having a polar group include a copolymer of an acrylic acid ester and maleic anhydride, an ethylene-vinyl acetate copolymer, and an ethylene-glycidyl methacrylate copolymer.

[0033] The anchor coat layer 2 may contain other components in addition to the first polyolefin, such as polyolefins other than the first polyolefin, silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyimides, melamine, and phenols.

[0034] The content of the first polyolefin in the anchor coat layer 2 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass.

[0035] The thickness of the anchor coat layer 2 may be, for example, 1 μm or more, 2 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the anchor coat layer 2 is 1 μm or more, the unevenness of the paper base material described above can be efficiently filled, and the vapor deposition layer described below can be uniformly laminated. Furthermore, if the thickness of the anchor coat layer 2 is 20 μm or less, the vapor deposition layer can be uniformly laminated while keeping costs down.

[0036] Examples of solvents contained in the coating liquid for the anchor coat layer 2 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. Among these, from the viewpoint of properties, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred. Furthermore, from the viewpoint of the environment, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred.

[0037] The anchor coat layer 2 can be formed by applying a coating solution containing at least the first polyolefin and a solvent to a paper substrate and drying it. To prevent blocking, the particle size of the first polyolefin in the coating solution should be large so that the contact area is small. While not particularly limited, the particle size may be 1 nm or more, 0.1 μm or more, 1 μm or less, 0.7 μm or less, or 0.5 μm or less.

[0038] [Vapour-deposited layer] The vapor-deposited layer 3 is a layer obtained by vapor-depositing a metal or an inorganic compound. The vapor-deposited layer may be obtained by vapor-depositing aluminum, or may be obtained by vapor-depositing aluminum oxide (AlO x ), silicon oxide (SiO x ) etc. may also be included.

[0039] The thickness of the vapor-deposited layer 3 may be appropriately set depending on the intended use, but is preferably 10 to 300 nm, more preferably 30 to 100 nm. A thickness of 10 nm or more of the vapor-deposited layer 3 makes it easy to ensure sufficient continuity of the vapor-deposited layer 3, while a thickness of 300 nm or less makes it easy to sufficiently suppress the occurrence of curling and cracking, and to easily achieve sufficient gas barrier performance and flexibility.

[0040] The deposition layer 3 is preferably formed by a vacuum deposition method from the viewpoint of oxygen gas barrier performance and film uniformity. There are known deposition methods such as vacuum deposition, sputtering, and chemical vapor deposition (CVD), but vacuum deposition is preferred due to its fast deposition rate and high productivity. Among vacuum deposition methods, deposition by electron beam heating is particularly effective because the deposition rate can be easily controlled by the irradiation area and electron beam current, and the temperature of the deposition material can be increased or decreased in a short time.

[0041] [Overcoat layer] The overcoat layer 4 is provided on the surface of the vapor-deposited layer 3 so as to be in contact with the vapor-deposited layer 3, and contains a second polyolefin having a polar group.

[0042] The second polyolefin having a polar group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0043] The second polyolefin having a polar group may be a copolymer of ethylene or propylene with an unsaturated carboxylic acid (an unsaturated compound having a carboxyl group, such as acrylic acid or methacrylic acid), an unsaturated carboxylic acid ester, or a salt of a carboxylic acid neutralized with a basic compound. Alternatively, a copolymer of ethylene or propylene with vinyl acetate, an epoxy compound, a chlorine compound, a urethane compound, a polyamide compound, or the like may be used.

[0044] Specific examples of the second polyolefin having a polar group include a copolymer of an acrylic acid ester and maleic anhydride, an ethylene-vinyl acetate copolymer, and an ethylene-glycidyl methacrylate copolymer.

[0045] Such an overcoat layer 4 has excellent flexibility, can suppress cracking of the vapor-deposited layer after bending (folding), and has excellent adhesion to the vapor-deposited layer. Furthermore, by including the second polyolefin described above, it is possible to form a dense film due to the crystallinity of the polyolefin, and water vapor barrier properties are exhibited. Furthermore, the presence of polar groups enables adhesion to the vapor-deposited layer. Furthermore, by including the second polyolefin described above, the overcoat layer 4 can also function as a heat-sealing layer, so there is no need to provide a separate heat-sealing layer.

[0046] The overcoat layer 4 may contain other components in addition to the second polyolefin, such as a silane coupling agent, organic titanate, polyacrylic, polyester, polyurethane, polycarbonate, polyurea, polyamide, polyolefin emulsion, polyimide, melamine, and phenol.

[0047] The content of the second polyolefin in the overcoat layer 4 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass.

[0048] The thickness of the overcoat layer 4 may be, for example, 0.05 μm or more, 0.5 μm or more, 1 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the overcoat layer 4 is 0.05 μm or more, it can fully fulfill its role as the heat seal layer described above. Furthermore, if the thickness of the overcoat layer 4 is 20 μm or less, it can fully fulfill its role as a barrier and adhere to the vapor deposition layer while keeping costs down.

[0049] Examples of solvents contained in the coating liquid for the overcoat layer 4 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. Among these, from the viewpoint of properties, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred. Furthermore, from the viewpoint of environmental friendliness, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred. The overcoat layer 4 can be formed by applying a coating liquid containing the second polyolefin and a solvent described above onto the vapor deposition layer and drying the coating liquid. The melting point of the second polyolefin in the coating liquid is preferably 70 to 160°C, more preferably 80 to 120°C. A low melting point of the second polyolefin has the advantage of lowering the heat-sealing start temperature. If the melting point of the second polyolefin is high, there is a high risk of blocking in a high-temperature environment. To prevent blocking, it is preferable that the particle size is large so that the contact area is small. While not particularly limited, the particle size may be 1 nm or more, 0.1 μm or more, 1 μm or less, 0.7 μm or less, or 0.5 μm or less.

[0050] The first polyolefin and the second polyolefin contained in the anchor coat layer 2 and the overcoat layer 4, respectively, may be the same or different, but considering ease of production, it is preferable that they are the same.

[0051] <Packaging bag> 2 is a perspective view showing a gusset bag 20 made of a gas barrier laminate 10. A packaging bag is produced by sealing the opening at the top of the gusset bag 20. The gusset bag 20 has portions where the gas barrier laminate 10 is folded (folded portions B1, B2). Folded portion B1 is a portion where the gas barrier laminate 10 is folded in a valley direction when viewed from the innermost layer side, while folded portion B2 is a portion where the gas barrier laminate 10 is folded in a mountain direction when viewed from the innermost layer side.

[0052] The packaging bag may be formed into a bag shape by folding one gas barrier laminate in half so that the overcoat layers 4 face each other, then folding it appropriately into the desired shape and heat sealing it, or may be formed into a bag shape by stacking two gas barrier laminates so that the overcoat layers 4 face each other, and then heat sealing it.

[0053] In the packaging bag according to this embodiment, the heat seal strength may be 2 N or more, or may be 4 N or more. The upper limit of the heat seal strength is not particularly limited, but may be, for example, 10 N or less.

[0054] The packaging bag can contain contents such as food, medicine, etc. It is particularly suitable for containing food such as sweets. The packaging bag according to this embodiment can maintain high gas barrier properties even when it has a shape with a folded portion.

[0055] In this embodiment, a gusset bag is given as an example of a packaging bag, but the gas barrier laminate according to this embodiment may be used to produce, for example, a pillow bag, a three-side sealed bag or a standing pouch. [Example]

[0056] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0057] <Preparation of gas barrier laminate> Example 1 Paper (coated paper, 55 g / m 2 A coating solution containing a carboxyl group salt (product name: Chemipearl S100, ionomer-based, particle size: <0.1 μm, solvent: water, IPA, manufactured by Mitsui Chemicals) was applied to the surface of the paper using a bar coater and dried in an oven to form an anchor coat layer. The anchor coat layer had a thickness of 3 μm. Subsequently, aluminum was vapor-deposited on the anchor coat layer. The thickness of the vapor-deposited aluminum layer was 50 nm. A solution containing a carboxyl group salt (product name: Chemipearl S100, ionomer-based, particle size: <0.1 μm, solvent: water, IPA, manufactured by Mitsui Chemicals) was then applied to the vapor-deposited layer using a bar coater and dried in an oven to form an overcoat layer, yielding a gas barrier laminate. The overcoat layer had a thickness of 3 μm. The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0058] Example 2 A gas barrier laminate was obtained in the same manner as in Example 1, except that the anchor coat layer was formed using a solution containing a carboxyl group salt (trade name: Chemipearl S300, ionomer-based, particle size: 0.5 μm, solvent: water, IPA, manufactured by Mitsui Chemicals). The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0059] Example 3 A gas barrier laminate was obtained in the same manner as in Example 1, except that the anchor coat layer was formed using a solution containing a carboxyl group salt (trade name: Chemipearl S500, ionomer-based, particle size: 0.7 μm, solvent: water, IPA, manufactured by Mitsui Chemicals). The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0060] Example 4 Except for changing the thickness of the anchor coat layer to 1 μm, a gas barrier laminate was obtained in the same manner as in Example 1. The weight of paper in the gas barrier laminate was approximately 85% by mass.

[0061] Example 5 Except for using silica as the vapor-deposited layer, a gas barrier laminate was obtained in the same manner as in Example 1. The weight of paper in the gas barrier laminate was approximately 82 mass %.

[0062] Example 6 Except for using alumina as the vapor-deposited layer, a gas barrier laminate was obtained in the same manner as in Example 1. The weight of paper in the gas barrier laminate was approximately 82 mass %.

[0063] Example 7 A polyolefin aqueous dispersion was prepared by neutralizing Bondine HX-8290 (trade name: manufactured by Arkema), a copolymer of acrylic acid ester and maleic anhydride, with triethylamine in a water / IPA mixed solvent. Note that maleic anhydride undergoes partial or complete ring opening in the water solvent to form a carboxylic acid, but after drying, it undergoes partial or complete dehydration and cyclization again. Paper (coated paper, 55 g / m 2 The polyolefin aqueous dispersion prepared above was coated on the surface of the paper and dried in an oven to form an anchor coat layer. The thickness of the anchor coat layer was 3 μm. Subsequently, aluminum was vapor-deposited on the anchor coat layer. The thickness of the aluminum vapor-deposited layer was 50 nm. The polyolefin aqueous dispersion was then coated on the vapor-deposited layer and dried in an oven to form an overcoat layer, thereby obtaining a gas barrier laminate. The thickness of the overcoat layer was 3 μm. The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0064] Example 8 A gas barrier laminate was obtained in the same manner as in Example 1, except that the anchor coat layer was formed from an ethylene-vinyl acetate copolymer (trade name: Chemipearl V300, particle size: 6 μm, solvent: water, IPA, manufactured by Mitsui Chemicals). The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0065] Example 9 Except for forming the overcoat layer using Chemipearl V300, a gas barrier laminate was obtained in the same manner as in Example 1. The weight of paper in the gas barrier laminate was approximately 82 mass %.

[0066] Example 10 A gas barrier laminate was obtained in the same manner as in Example 1, except that the anchor coat layer was formed from an ethylene-glycidyl methacrylate copolymer (product name: Sepolsion G515, manufactured by Sumitomo Seika Chemicals). The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0067] Example 11 A gas barrier laminate was obtained in the same manner as in Example 1, except that the overcoat layer was formed from an ethylene-glycidyl methacrylate copolymer (product name: Sepolsion G515, manufactured by Sumitomo Seika Chemicals). The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0068] Example 12 Paper (coated paper, 55 g / m 2 An aqueous PVA solution was applied to the surface of the paper and dried to form a first anchor coat layer. The thickness of the first anchor coat layer was 3 μm. Next, a second anchor coat layer was formed using Chemipearl S100. The thickness of the second anchor coat layer was 1 μm. A gas barrier laminate was obtained by the same procedure as in Example 1 except for this. The weight of paper in the gas barrier laminate was approximately 81% by mass.

[0069] Example 13 An anchor coat layer (thickness: 3 μm) was formed using Chemipearl S100, a vapor deposition layer was laminated on it, and then another anchor coat layer (thickness: 3 μm) was formed using Chemipearl S100, and a vapor deposition layer was laminated on it. Otherwise, a gas barrier laminate was obtained using the same procedures as in Example 1. The weight of paper in the gas barrier laminate was approximately 81% by mass.

[0070] (Comparative Example 1) A gas barrier laminate was obtained in the same manner as in Example 1, except that the anchor coat layer was made of a urethane-cured acrylic resin, which is a cured product of acrylic polyol (acrylic polyol is a polymer of an acrylic acid derivative monomer or a polymer of an acrylic acid derivative monomer and another monomer, and has hydroxyl groups at the terminals) and polyisocyanate. The weight of paper in the gas barrier laminate was approximately 82% by mass.

[0071] (Comparative Example 2) A gas barrier laminate was obtained in the same manner as in Example 1, except that the overcoat layer was formed from a mixture of PVA and TEOS hydrolysates, and Chemipearl S500 was further applied to the overcoat layer to a thickness of 3 μm as a heat seal layer. The weight of paper in the gas barrier laminate was approximately 82 mass %.

[0072] <Measurement of water vapor permeability> The water vapor permeability of the gas barrier laminates according to the examples and comparative examples was measured by the MOCON method. The measurement conditions were a temperature of 40°C and a relative humidity of 90%. A 600g roller was rolled at a speed of 300mm / min to create a crease in the gas barrier laminate, and the water vapor permeability of the gas barrier laminate after opening was also measured in the same manner. In Tables 1, 2 and 3, "valley fold" indicates the water vapor permeability after the gas barrier laminate was valley-folded as viewed from the overcoat layer side, and "mountain fold" indicates the water vapor permeability after the gas barrier laminate was mountain-folded as viewed from the overcoat layer side. The results are shown in Tables 1, 2 and 3 in units of [g / m 2 ·day].

[0073] <Heat seal strength measurement> Two gas barrier laminates were placed together with the overcoat layers 4 facing each other and thermocompression bonded using a heat seal bar at 120°C, 0.2 MPa, and 1 second. The thermocompression bonded portion was cut into a 15 mm width and the strength measured when T-peeling using a tensile tester was recorded. The peeling speed was 300 mm / min. The results are shown in Tables 1, 2, and 3 in units of [N / 15 mm].

[0074] [Table 1]

[0075] [Table 2]

[0076] [Table 3] [Explanation of symbols]

[0077] 1...paper substrate, 2...anchor coat layer, 3...vapor deposition layer, 4...overcoat layer, 10...gas barrier laminate, 20...gusset bag, B1, B2...folded portion

Claims

1. A gas barrier laminate used in the manufacture of a packaging bag for containing contents, comprising: A paper substrate; an anchor coat layer containing a first polyolefin having a polar group; a deposition layer; an overcoat layer comprising a second polyolefin having polar groups; are provided in this order from the outside to the inside, The gas barrier laminate is produced so that the overcoat layer constitutes the innermost layer of the gas barrier laminate and also constitutes the inner surface of the packaging bag.

2. 2. The gas barrier laminate according to claim 1, wherein the first polyolefin having a polar group has at least one group selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

3. 3. The gas barrier laminate according to claim 1, wherein the second polyolefin having a polar group has at least one group selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

4. 2. The gas barrier laminate according to claim 1, wherein the first polyolefin having a polar group is a copolymer of an acrylic ester and maleic anhydride.

5. 2. The gas barrier laminate according to claim 1, wherein the first polyolefin having a polar group is an ethylene-vinyl acetate copolymer.

6. 2. The gas barrier laminate according to claim 1, wherein the first polyolefin having a polar group is an ethylene-glycidyl methacrylate copolymer.

7. 7. The gas barrier laminate according to claim 1, wherein the second polyolefin having a polar group is a copolymer of an acrylic ester and maleic anhydride.

8. 7. The gas barrier laminate according to claim 1, wherein the second polyolefin having a polar group is an ethylene-vinyl acetate copolymer.

9. 7. The gas barrier laminate according to claim 1, wherein the second polyolefin having a polar group is an ethylene-glycidyl methacrylate copolymer.

10. The gas barrier laminate according to any one of claims 1 to 9, wherein the anchor coat layer has a thickness of 1 µm or more.

11. 11. The gas barrier laminate according to claim 1, wherein the weight of the paper is 50% by mass or more based on the weight of the entire gas barrier laminate.

12. A gas barrier laminate described in any one of claims 1 to 11, wherein the overcoat layer is arranged so as to be in contact with the vapor deposition layer.

13. The gas barrier laminate according to any one of claims 1 to 12, wherein the paper substrate has a mass per unit area of ​​20 to 500 g / m 2 .

14. A packaging bag used to store contents, comprising the gas barrier laminate according to any one of claims 1 to 13, A packaging bag, wherein the overcoat layers of the gas barrier laminate are stacked so as to face each other and heat-sealed to form a bag shape, and the overcoat layers form the inner surface of the packaging bag.

15. The packaging bag according to claim 14, having a folded portion.

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