Laminate

Abstract

To provide a laminate using paper, which has not only initial oil resistance but also sufficient oil resistance even after being bent.SOLUTION: A laminate has a structure in which at least a paper base material, an anchor coat layer, an aluminum vapor deposition layer, and an overcoat layer are laminated in this order.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to laminates and packaging bags. [Background technology]

[0002] In many fields, including food, beverages, pharmaceuticals, and chemicals, packaging materials are used that are appropriate for the contents. Packaging materials are required to have gas barrier properties, preventing the permeation of water vapor and other gases that can cause deterioration of the contents. Furthermore, depending on the contents, packaging materials may also require oil resistance to prevent oil from seeping out.

[0003] In recent years, there has been a growing movement to reduce plastic use, driven by increased environmental awareness stemming from issues such as marine plastic waste. From the perspective of reducing the amount of plastic material used, the use of paper as a substitute for plastic materials is being considered in various fields. For example, Patent Document 1 below discloses a laminate in which a barrier layer is laminated onto paper. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-69783 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Paper has the advantage of being easy to process due to its crease-holding ability (also known as dead-holding ability). However, our research has revealed that when using packaging bags with sharper creases (pillow packaging, three-side seal packaging, and gusset packaging), there is still room for improvement in that cracks occur in the barrier layer, reducing oil resistance.

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

[0007] Therefore, the present disclosure aims to provide a laminate made of paper that has sufficient oil resistance not only initially but also after being folded, and a packaging bag containing the same. [Means for solving the problem]

[0008] To solve the above problems, this disclosure provides the following laminates and packaging bags. [1] A laminate having a structure in which at least a paper substrate, an anchor coat layer, an aluminum vapor-deposited layer, and an overcoat layer are laminated in this order, wherein the aluminum vapor-deposited layer has a full width at half maximum of 1.6° or more of the peak of the (111) crystal plane of aluminum in X-ray diffraction measurement. [2] The laminate according to [1] above, wherein the anchor coat layer comprises a polyolefin or polyvinyl alcohol-based resin having polar groups. [3] The laminate according to [1] or [2] above, wherein the overcoat layer comprises a polyolefin having polar groups. [4] The laminate according to any one of [1] to [3] above, wherein the hardness of the anchor coat layer measured by nanoindentation in a cross-section in the thickness direction of the laminate is 0.3 GPa or less. [5] The laminate according to any one of [1] to [4] above, wherein the hardness of the overcoat layer measured by nanoindentation in a cross-section in the thickness direction of the laminate is 0.3 GPa or less. [6] The laminate according to any of [1] to [5] above, wherein the thickness of the aluminum vapor deposition layer is 20 nm or more and 100 nm or less. [7] The aluminum vapor-deposited layer is a laminate according to any one of [1] to [6] above, wherein the full width at half maximum of the peak of the (111) crystal plane of aluminum in X-ray diffraction measurement is 2.0° or more and 15.0° or less. [8] The laminate according to [7] above, wherein the aluminum vapor-deposited layer is in contact with a resin layer containing an ionomer or a polyvinyl alcohol-based resin with a degree of saponification of 95% or more. [9] A packaging bag containing the laminate described in any of [1] to [8] above.

[10] The packaging bag described in [9] above, having a folded portion. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a laminate made of paper that has sufficient oil resistance not only initially but also after being folded, and a packaging bag containing the same. Because the above laminate uses paper, it has the crease-retaining properties that are characteristic of paper, and contributes to reducing the amount of plastic material used. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing a laminate according to one embodiment of the present disclosure. [Figure 2] A perspective view showing a packaging bag according to one embodiment of this disclosure. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described in detail below, with reference to the drawings as appropriate. However, this disclosure is not limited to the embodiments described below.

[0012] <Laminate> The laminate according to this embodiment is a laminate having a structure in which at least a paper substrate, an anchor coat layer, an aluminum vapor-deposited layer, and an overcoat layer are laminated in this order, wherein the aluminum vapor-deposited layer is a laminate in which the full width at half maximum (FWHM) of the peak of the (111) crystal plane of aluminum in X-ray diffraction measurement is 1.6° or more. Here, the FWHM of the aluminum vapor-deposited layer in X-ray diffraction represents the degree of lattice strain of the aluminum crystal structure. If the strain is large, the FWHM is large, and if the strain is small, the FWHM is small. Also, the smaller the strain, the denser the aluminum crystal structure is. In the above laminate, by having the FWHM of the aluminum vapor-deposited layer be 1.6° or more, the density of the aluminum crystal structure can be moderately reduced to a sparse state. As a result, the stress applied to the aluminum vapor-deposited layer when the laminate is bent is distributed throughout the entire layer, which suppresses the occurrence of cracks in the aluminum vapor-deposited layer when bent, and reduces the size of cracks that occur in the aluminum vapor-deposited layer. Therefore, with the above laminate, sufficient oil resistance can be obtained not only initially but also after bending. Furthermore, with the above laminate, by keeping the half-width of the aluminum vapor-deposited layer within the above range, sufficient water vapor barrier properties can be obtained not only initially but also after bending. Moreover, with the above laminate, if a material having oxygen barrier properties is used for the anchor coat layer, sufficient oxygen barrier properties can be obtained not only initially but also after bending by keeping the half-width of the aluminum vapor-deposited layer within the above range. The laminate according to this embodiment is useful as an oil-resistant laminate or a gas barrier laminate.

[0013] Furthermore, conventional gas barrier laminates had room for improvement in that their water vapor barrier properties deteriorated when stored under high temperature and high humidity conditions. When a gas barrier laminate whose water vapor barrier properties had deteriorated after being stored under high temperature and high humidity conditions (40°C, 90% humidity) was observed under a microscope using transmitted light, numerous minute bright spots were confirmed, suggesting that the water vapor barrier properties deteriorated due to transmission defects occurring in the aluminum vapor-deposited layer. In contrast, the laminate according to this embodiment has an aluminum vapor-deposited layer in which the full width at half maximum of the peak of the (111) crystal plane of aluminum in X-ray diffraction measurements is 1.6° or more. This suppresses the occurrence of transmission defects in the aluminum vapor-deposited layer even when stored under high temperature and high humidity conditions, thereby suppressing the deterioration of water vapor barrier properties. The inventors speculate as follows on why this effect is obtained.

[0014] The generation of transmission defects in the aluminum vapor deposition layer is affected by the pitting corrosion of aluminum caused by corrosive ions and the expansion and contraction stress caused by dimensional changes associated with the absorption and desorption of moisture by the paper substrate. From the perspective of the crystallinity of the aluminum vapor deposition layer, it can be said that a higher crystallinity is superior in terms of resistance to corrosive ions, but in terms of stress resistance, an amorphous material that is more easily able to follow expansion and contraction is considered to be superior. Here, it is considered that the aluminum vapor deposition layer has a structure in which the amorphous part fills around the crystallites. In addition, the broadening of the X-ray diffraction line width of aluminum is derived from the crystallite diameter and crystal strain. A narrow X-ray diffraction line width is considered to be a state clearly divided into crystallites composed of an ideal crystal lattice and an amorphous part. Therefore, when the X-ray diffraction line width is narrow, it is presumed that the ideal crystal lattice or the destruction between the crystal / amorphous due to pitting corrosion and expansion and contraction stress in the amorphous part is likely to occur. On the other hand, a wide X-ray diffraction line width is considered to have a distorted crystal structure and an ambiguous separation between the crystalline part / amorphous part. Therefore, when the X-ray diffraction line width is wide, it is presumed that the destruction due to pitting corrosion and expansion and contraction stress is suppressed, and transmission defects are less likely to occur. For the above reasons, when the half-value width in the X-ray diffraction of the aluminum vapor deposition layer is 1.6° or more, it is considered that even when the laminate is stored under high temperature and high humidity, the occurrence of transmission defects in the aluminum vapor deposition layer can be suppressed, and the deterioration of the water vapor barrier property can be suppressed. Such an effect is more显著 when the above half-value width is 2.0° or more.

[0015] FIG. 1 is a schematic cross-sectional view showing a laminate according to an embodiment. The laminate 10 according to an embodiment includes a paper substrate 1, an anchor coat layer 2, an aluminum vapor deposition layer 3, and an overcoat layer 4 in this order.

[0016] The thickness of the laminate 10 may be 20 to 100 μm, may be 30 to 80 μm, or may be 40 to 60 μm. When the thickness of the laminate 10 is within the above range, the laminate 10 can obtain better water vapor barrier properties and oil resistance not only initially but also after being bent.

[0017] [Paper substrate] The paper substrate 1 may be paper whose main component is plant-derived pulp. Specific examples of the paper substrate 1 include fine paper, special fine paper, coated paper, art paper, cast coated paper, imitation paper, kraft paper, and glassine paper. The basis weight of the paper substrate 1 is 20-500 g / m². 2 , or 30-100g / m 2 That's fine.

[0018] The paper substrate 1 may have a coating layer on at least the side in contact with the anchor coat layer 2. If the paper substrate 1 has a coating layer, the paper substrate 1 may have at least a paper layer and a coating layer. The coating layer may be provided on both surfaces of the paper substrate 1. By providing a coating layer, it is possible to prevent the anchor coat layer 2 from seeping into the paper, and it can also act as a sealer to fill in the irregularities of the paper, allowing the anchor coat layer 2 to be formed uniformly without defects. For example, the coating layer may use various copolymers such as styrene-butadiene, styrene-acrylic, and ethylene-vinyl acetate as binder resins, polyvinyl alcohol resins, cellulose resins, paraffin (wax), etc., and may contain clay, kaolin, calcium carbonate, talc, mica, etc. as fillers. The coating layer may be a clay coating layer containing clay as at least as a filler.

[0019] If the paper substrate 1 is provided with a coating layer, the thickness of the coating layer may be 1.5 μm or more and 15 μm or less. The thickness of the coating layer may be 1.8 μm or more, 3 μm or more, 5 μm or more, or 6 μm or more. The thickness of the coating layer may be 12 μm or less or 10 μm or less. When the thickness of the coating layer is within the above range, the laminate 10 can obtain better water vapor barrier properties and oil resistance not only initially but also after being folded.

[0020] The thickness of the paper substrate 1 may be 20 to 100 μm, 30 to 80 μm, or 40 to 60 μm. When the thickness of the paper substrate 1 is within the above range, the laminate 10 can obtain better water vapor barrier properties and oil resistance not only initially but also after being folded.

[0021] The ratio of the thickness of the coating layer to the thickness of the paper substrate 1 may be 3-25% or 5-20%. When this ratio is within the above range, the laminate 10 can obtain better water vapor barrier properties and oil resistance not only initially but also after being folded.

[0022] The weight of paper is preferably 50% or more by mass of the entire laminate, more preferably 70% or more by mass, and even more preferably 80% or more by mass. If the weight of paper is 50% or more by mass of the entire laminate, the amount of plastic material used can be sufficiently reduced, the entire laminate can be said to be made of paper, and it has excellent recyclability.

[0023] [Anchor coat layer] The anchor coat layer 2 is provided on the surface of the paper substrate 1 to improve adhesion between the paper substrate 1 and the aluminum vapor deposition layer 3 (described later), and to improve the gas barrier properties and oil resistance of the laminate. The anchor coat layer 2 may contain a polyolefin or polyvinyl alcohol-based resin having polar groups.

[0024] When the anchor coat layer 2 contains a polyolefin having polar groups, the anchor coat layer 2 exhibits excellent flexibility, suppressing cracking of the aluminum vapor-deposited layer 3 after bending (folding), and improving adhesion between the anchor coat layer 2 and the aluminum vapor-deposited layer 3. Furthermore, the inclusion of a polyolefin having polar groups enables the formation of a dense film due to the crystalline properties of the polyolefin, resulting in water vapor barrier properties and oil resistance. The crystalline properties of the polyolefin provide water vapor barrier properties and oil resistance, while the presence of polar groups ensures adhesion with the aluminum vapor-deposited layer 3.

[0025] A polyolefin having a polar group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic acid anhydride group, and a carboxylic acid ester.

[0026] As the polyolefin having polar groups, copolymers of ethylene or propylene with unsaturated carboxylic acids (unsaturated compounds having carboxyl groups such as acrylic acid, methacrylic acid, and maleic anhydride), unsaturated carboxylic acid esters, and salts obtained by neutralizing carboxylic acids with basic compounds may be used. In addition, copolymers with vinyl acetate, epoxy compounds, chlorine compounds, urethane compounds, polyamide compounds, etc., may also be used.

[0027] Examples of polyolefins having polar groups include copolymers of acrylic acid esters and maleic anhydride, ethylene-vinyl acetate copolymers, and ethylene-glycidyl methacrylate copolymers.

[0028] On the other hand, when the anchor coat layer 2 contains a polyvinyl alcohol-based resin, the polyvinyl alcohol-based resin has polar groups (hydroxyl groups), and these polar groups readily bond with metals such as aluminum in the aluminum vapor-deposited layer 3, thus improving the adhesion between the aluminum vapor-deposited layer 3 and the anchor coat layer 2. Furthermore, such an anchor coat layer 2 has excellent flexibility, which can suppress cracking of the aluminum vapor-deposited layer 3 after bending (folding). In addition, the inclusion of a polyvinyl alcohol-based resin in the anchor coat layer 2 can improve the oxygen barrier properties of the laminate.

[0029] Polyvinyl alcohol-based resins are resins that contain vinyl alcohol as a constituent unit. Examples of polyvinyl alcohol-based resins include fully saponified polyvinyl alcohol resins, partially saponified polyvinyl alcohol resins, modified polyvinyl alcohol resins, and ethylene-vinyl alcohol copolymer resins. From the viewpoint of oxygen barrier properties, a higher degree of saponification of the polyvinyl alcohol resin is preferable, which may be 95% or more, and may be 98% or more.

[0030] The anchor coat layer 2 may contain both a polyolefin having polar groups and a polyvinyl alcohol-based resin.

[0031] The anchor coat layer 2 may contain other components in addition to the polyolefin and polyvinyl alcohol-based resin having the polar groups mentioned above. Examples of other components include polyolefins other than the polyolefin having the polar groups mentioned above, silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyimides, melamines, phenols, and the like.

[0032] The content of the polyolefin or polyvinyl alcohol-based resin having the polar group 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.

[0033] The thickness of the anchor coat layer 2 may be, for example, 0.5 μm or more, 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 0.5 μm or more, the irregularities of the paper substrate described above can be efficiently filled, and the aluminum vapor-deposited layer described later can be uniformly laminated. Also, if the thickness of the anchor coat layer 2 is 20 μm or less, the aluminum vapor-deposited layer can be uniformly laminated while keeping costs down.

[0034] The anchor coat layer 2 may have a hardness of 0.3 GPa or less, as measured by nanoindentation in a cross-section in the thickness direction of the laminate 10. Such an anchor coat layer 2 has excellent flexibility, can suppress cracking of the aluminum vapor-deposited layer 3 after bending (folding), and can improve the adhesion between the anchor coat layer 2 and the aluminum vapor-deposited layer 3.

[0035] Examples of solvents included in the coating solution 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 individually or in combination of two or more. Among these, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred from the viewpoint of properties. Furthermore, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred from the viewpoint of environmental impact.

[0036] The anchor coat layer 2 can be obtained by applying a coating solution containing the above-mentioned polar group-containing polyolefin or polyvinyl alcohol-based resin and solvent onto a paper substrate and then drying it.

[0037] [Aluminum vapor-deposited layer] The aluminum vapor-deposited layer 3 is a layer on which aluminum or an aluminum compound has been deposited. The aluminum vapor-deposited layer may be obtained by depositing aluminum, or aluminum oxide (AlO x ), silicon dioxide (SiO₂) x ) and other similar items may also be included.

[0038] The thickness of the aluminum vapor-deposited layer 3 can be set appropriately depending on the application, but is preferably 10 to 300 nm, more preferably 20 to 100 nm, and even more preferably 30 to 100 nm. Setting the thickness of the aluminum vapor-deposited layer 3 to 10 nm or more makes it easier to ensure sufficient continuity of the aluminum vapor-deposited layer 3, and setting it to 300 nm or less makes it easier to suppress the occurrence of curling and cracking, and to achieve sufficient gas barrier performance, oil resistance, and flexibility. Furthermore, setting the thickness of the aluminum vapor-deposited layer to 20 nm or more and 100 nm or less makes the aluminum vapor-deposited layer less prone to cracking, and sufficient water vapor barrier performance and oil resistance can be obtained even after bending. From the viewpoint of further suppressing the deterioration of the water vapor barrier performance of the laminate 10 when stored under high temperature and high humidity, the thickness of the aluminum vapor-deposited layer 3 may be 50 to 300 nm, 60 to 150 nm, or 60 to 100 nm.

[0039] The aluminum vapor-deposited layer 3 is preferably deposited by a vacuum deposition method from the viewpoint of water vapor and oxygen gas barrier performance, oil resistance, and film uniformity. Known deposition methods include vacuum deposition, sputtering, and chemical vapor deposition (CVD), but vacuum deposition is preferred due to its high deposition rate and productivity. Among vacuum deposition methods, electron beam heating is particularly effective because the deposition rate can be easily controlled by the irradiation area and electron beam current, and the heating and cooling of the deposition material can be performed in a short time.

[0040] The aluminum vapor-deposited layer 3 is a layer in which the full width at half maximum (FWHM) of the peak of the (111) crystal plane of aluminum in X-ray diffraction measurements is 1.6° or more. The above FWHM may be 1.8° or more, 2.0° or more, or 2.1° or more. When the FWHM is 1.6° or more, it is possible to suppress the occurrence of cracks in the aluminum vapor-deposited layer 3 when the laminate 10 is bent, and to suppress the decrease in gas barrier properties and oil resistance after bending. This effect is more pronounced when the above FWHM is 2.0° or more. Furthermore, when the above FWHM is 1.6° or more, it is possible to suppress the occurrence of permeation defects in the aluminum vapor-deposited layer 3 even when the laminate 10 is stored under high temperature and high humidity conditions (for example, under a 40°C 90% environment), and to suppress the deterioration of the water vapor barrier properties of the laminate 10. This effect is also more pronounced when the above FWHM is 2.0° or more. The upper limit of the above-mentioned full width at half maximum (FWHM) may be, for example, 15.0° or less, or 10.0° or less, from the viewpoint of the density of the aluminum crystal structure. If the resin layer in contact with the aluminum vapor-deposited layer contains an ionomer or a polyvinyl alcohol-based resin with a saponification degree of 95% or higher, the aluminum vapor-deposited layer is susceptible to corrosion. This problem is more likely to occur if the crystallinity of the aluminum vapor-deposited layer is low. If the above-mentioned FWHM is 15.0° or less, corrosion of the aluminum vapor-deposited layer becomes less likely, even if the resin layer in contact with the aluminum vapor-deposited layer contains an ionomer or a polyvinyl alcohol-based resin with a high saponification degree. This effect is even more pronounced when the above-mentioned FWHM is 10.0° or less. In order to achieve the above effects, it is preferable that the above half-width is between 1.6° and 15.0°, 1.6° and 10.0°, 1.6° and 7.0°, 1.6° and 5.0°, 2.0° and 15.0°, 2.0° and 10.0°, 2.0° and 7.0°, or 2.0° and 5.0°.

[0041] The full width at half maximum (2θ) of the peak of the (111) crystal plane of aluminum in the aluminum vapor-deposited layer 3 is measured using an X-ray diffractometer. For example, an ATX-G (product name) manufactured by Rigaku Electric Co., Ltd. can be used as the X-ray diffractometer. The measurement can be performed on the overcoat layer 4 using the laminate as the sample, fixed on a glass slide. For the X-ray diffraction of aluminum, the full width at half maximum at the peak corresponding to the (111) plane (d=2.34) at 2θ=38.5° is measured. The measurement conditions are as follows. Light source: CuKα line Tube voltage: 50kV Tube current: 300mA Optical system: Parallel beam optical system Scanning method: 2θ / θ method Measurement range: 30°~50° Sampling step: 0.02° Scan speed: 2° / min slit S1: 10.0mm x 1.0mm S2: 10.0mm x 0.5mm Sollar(res): 0.4mm

[0042] The above-mentioned full width at half maximum (FWHM) can be controlled by adjusting the conditions during the deposition of the aluminum vapor-deposited layer 3. For example, the FWHM can be controlled by adjusting the pressure inside the deposition chamber during the deposition of the aluminum vapor-deposited layer 3. Here, increasing the pressure inside the deposition chamber increases the FWHM, and decreasing the pressure inside the deposition chamber decreases the FWHM. The pressure inside the deposition chamber during the deposition of the aluminum vapor-deposited layer 3 may be 0.05 Pa or higher, 0.10 Pa or higher, or 0.20 Pa or higher, as it is easier to adjust the FWHM to 1.6° or higher. The upper limit of the pressure is not particularly limited as long as the deposition of the aluminum vapor-deposited layer 3 is possible, but for example, it may be 0.50 Pa or lower, or 0.40 Pa or lower.

[0043] [Overcoat layer] The overcoat layer 4 is provided on the surface of the aluminum vapor-deposited layer 3, in contact with the aluminum vapor-deposited layer 3. The overcoat layer may contain a polyolefin having polar groups.

[0044] A polyolefin having a polar group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic acid anhydride group, and a carboxylic acid ester.

[0045] As the polyolefin having polar groups, copolymers of ethylene or propylene with unsaturated carboxylic acids (unsaturated compounds having carboxyl groups such as acrylic acid and methacrylic acid), unsaturated carboxylic acid esters, and salts obtained by neutralizing carboxylic acids with basic compounds may be used. In addition, copolymers with vinyl acetate, epoxy compounds, chlorine compounds, urethane compounds, polyamide compounds, etc., may also be used.

[0046] Examples of polyolefins having polar groups include copolymers of acrylic acid esters and maleic anhydride, ethylene-vinyl acetate copolymers, and ethylene-glycidyl methacrylate copolymers.

[0047] By containing a polyolefin with polar groups, the overcoat layer 4 exhibits excellent flexibility, suppressing cracking of the aluminum vapor-deposited layer after bending (folding), and also exhibits excellent adhesion to the aluminum vapor-deposited layer. Furthermore, the inclusion of the aforementioned polyolefin with polar groups enables the formation of a dense film due to the crystalline nature of the polyolefin, resulting in water vapor barrier properties and oil resistance. In addition, the presence of polar groups ensures adhesion to the aluminum vapor-deposited layer. Moreover, because the overcoat layer 4 contains the above-mentioned polyolefin with polar groups, it can also function as a heat seal layer, eliminating the need for a separate heat seal layer.

[0048] The overcoat layer 4 may contain other components in addition to the polyolefin having the polar group described above. Examples of other components include silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyolefin emulsions, polyimides, melamines, phenols, and the like.

[0049] The content of the polyolefin having polar groups 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.

[0050] 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, 2 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 perform the role of a heat seal layer as described above. If the thickness of the overcoat layer 4 is 20 μm or less, it can fully exhibit adhesion and barrier properties with the aluminum vapor-deposited layer while keeping costs down. Furthermore, by setting the thickness of the overcoat layer 4 to 2 μm or more and 10 μm or less, the aluminum vapor-deposited layer becomes less prone to cracking, and sufficient water vapor barrier properties and oil resistance can be obtained even after bending.

[0051] In the laminate 10, when the overcoat layer 4 contains a polyolefin having polar groups, the thickness of the overcoat layer 4 is 2 μm or more and 10 μm or less, and the thickness of the aluminum vapor-deposited layer 3 is 20 nm or more and 100 nm or less, the aluminum vapor-deposited layer 3 becomes less prone to cracking, and the effect of obtaining sufficient water vapor barrier properties and oil resistance even after bending is particularly remarkable.

[0052] The overcoat layer 4 may have a hardness of 0.3 GPa or less, as measured by nanoindentation in a cross-section in the thickness direction of the laminate 10. Such an overcoat layer 4 has excellent flexibility, can suppress cracking of the aluminum vapor-deposited layer 3 after bending (folding), and can suppress a decrease in gas barrier properties and oil resistance.

[0053] Examples of solvents included in the coating solution 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 individually or in combination of two or more. Among these, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred from the viewpoint of properties. Furthermore, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred from the viewpoint of the environment.

[0054] The overcoat layer 4 can be obtained by applying a coating solution containing the above-mentioned polyolefin having polar groups and a solvent onto the aluminum vapor-deposited layer and drying it. The melting point of the polyolefin having polar groups in the coating solution is preferably 70 to 160°C, and more preferably 80 to 120°C. A lower melting point of the polyolefin having polar groups has the advantage of lowering the start-up temperature during heat sealing. A lower melting point of the polyolefin having polar groups increases the risk of blocking in high-temperature environments. From the viewpoint of preventing blocking, it is preferable to have a larger particle size so that the contact area is smaller. Although not particularly limited, the particle size may be 1 nm or larger, 0.1 μm or larger, 1 μm or less, 0.7 μm or less, or 0.5 μm or less.

[0055] (Method for cross-sectional processing of measurement samples using nanoindentation method) Measurement by nanoindentation involves measuring the anchor coat layer 2 and the overcoat layer 4 from the cross-section of the laminate 10. The laminate sample, including the anchor coat layer 2 and the overcoat layer 4, is cut with a razor blade into a strip or wedge shape and embedded in resin. A photocurable resin (e.g., D-800 from Toagosei Co., Ltd.) is used as the embedding resin, and it is cured by light irradiation after embedding. The cured sample embedding resin is fixed with an AFM sample holder insert, and trimming and cross-sectional cutting of the laminate are performed with a glass knife at room temperature (25°C). Cross-sectional cutting is then performed with a diamond knife at a cutting speed of 1.0 mm / s and a cutting film thickness of 200 nm until a mirror finish is achieved. The cross-sectional sample is then used for measurement by nanoindentation while fixed with an AFM sample holder insert. For example, a Leica EMUC7 ultramicrotome can be used as the cross-sectional cutting device. The cutting direction should be parallel to the layer interface.

[0056] (Measurement method using nanoindentation) The hardness and composite modulus of the anchor coat layer and overcoat layer are expressed as those calculated by the nanoindentation method. The nanoindentation method is a measurement method that obtains the mechanical properties of a sample by performing a quasi-static indentation test on the target object to be measured. For the measuring device, for example, the Hysitron TI-Premier (product name) manufactured by Bruker Japan Co., Ltd. can be used. For the indenter, a Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. can be used. In the nanoindentation method, first, a shape image of the sample is obtained by scanning the cross-section of the sample with the diamond indenter, and the measurement position of the desired layer is specified. Then, at room temperature (25°C) in displacement control mode, the sample is indented to a depth of 80 nm at an indentation speed of 80 nm / second, held at the maximum depth for 1 second, and then unloaded at a speed of 80 nm / second. The method for calculating the hardness and composite modulus involves pre-testing a standard sample of fused silica and calibrating the relationship between the contact depth and contact projected area between the indenter and the sample. Subsequently, the unloading curve in the 60-95% range relative to the maximum load at unloading is analyzed using the Oliver-Pharr method to calculate the stiffness and composite modulus.

[0057] The hardness of the anchor coat layer 2 and the overcoat layer 4, measured by nanoindentation in a cross-section in the thickness direction of the laminate 10, may be 0.3 GPa or less. This mitigates the direct transmission of deformation stress in the paper substrate caused by bending of the laminate to the aluminum vapor-deposited layer, preventing defects from occurring in the aluminum vapor-deposited layer, and thus suppressing the deterioration of gas barrier properties and oil resistance after bending. From this viewpoint, the hardness of the anchor coat layer 2 and the overcoat layer 4 may be 0.25 GPa or less, and 0.2 GPa or less. The lower limit of hardness is not particularly limited, but from the viewpoint of obtaining sufficient strength to maintain gas barrier properties and oil resistance, it may be 0.05 MPa or higher.

[0058] In order to form a flexible anchor coat layer 2 and overcoat layer 4 in the thickness direction cross-section of the laminate 10, where the hardness measured by nanoindentation is 0.3 GPa or less, it is preferable to use a resin material in which the elongation at the break point of the dried film, measured in an atmosphere of 20°C and 65% RH according to JIS K7161, is preferably 150% or more, more preferably 200% or more, to form the anchor coat layer 2 and overcoat layer 4.

[0059] <Packaging bag> Figure 2 is a perspective view showing a gusset bag 20 made of a laminate 10. The packaging bag is manufactured by sealing the opening at the top of the gusset bag 20. The gusset bag 20 has folded sections (folded sections B1, B2) where the laminate 10 is folded. Folded section B1 is where the laminate 10 is valley-folded when viewed from the innermost layer side, while folded section B2 is where the laminate 10 is mountain-folded when viewed from the innermost layer side.

[0060] The packaging bag may be formed by folding a single laminate in half so that the overcoat layers 4 face each other, then folding it appropriately to the desired shape and heat-sealing it, or by stacking two laminates so that the overcoat layers 4 face each other and then heat-sealing them to form a bag.

[0061] In the packaging bag according to this embodiment, the heat seal strength may be 2N or more, or 4N or more. There is no particular upper limit to the heat seal strength, but it may be, for example, 10N or less.

[0062] The packaging bag can contain contents such as food and pharmaceuticals. It is particularly suitable for containing confectionery and similar items. The packaging bag according to this embodiment can maintain high gas barrier properties and oil resistance even when it has a folded portion.

[0063] In this embodiment, a gusseted bag was given as an example of a packaging bag, but the laminate according to this embodiment may also be used to produce, for example, pillow bags, three-sided sealed bags, or standing pouches. [Examples]

[0064] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to these examples.

[0065] <Fabrication of laminates> (Example 1) A paper substrate having a 5 μm thick clay coat layer (total thickness including the clay coat layer: 55 μm) was coated onto the clay coat layer side surface using a bar coater with an aqueous dispersion of polyolefin containing a carboxyl group salt (manufactured by Sumitomo Seika Co., Ltd., product name: Zychsen AC, particle size: less than 0.2 μm, solvent: water / IPA = 1 / 1 (mass ratio), solid content concentration: 22.5 mass%), and dried in an oven to form a 3 μm thick anchor coat layer.

[0066] Next, Al deposition was performed on the anchor coat layer using a vacuum deposition method to form a 50 nm thick Al deposition layer (aluminum deposition layer). The pressure inside the deposition chamber during aluminum deposition was adjusted to the values ​​shown in Table 1.

[0067] Next, an aqueous dispersion of polyolefin containing a carboxyl group salt (manufactured by Mitsui Chemicals, Inc., product name: Chemipearl S100, particle size: less than 0.1 μm, solvent: water / IPA = 1 / 1 (mass ratio), solid content concentration: 20.0 mass) was coated onto the Al vapor-deposited layer using a bar coater and dried in an oven to form a 3 μm thick overcoat layer. This obtained a laminate.

[0068] (Example 2) A laminate was obtained in the same manner as in Example 1, except that the pressure inside the deposition chamber when forming the Al deposition layer was changed to the value shown in Table 1.

[0069] (Example 3) A laminate was obtained in the same manner as in Example 1, except that the paper substrate was changed to a paper substrate having a clay coat layer with a thickness of 5 μm (thickness including the clay coat layer: 50 μm).

[0070] (Example 4) A laminate was obtained in the same manner as in Example 1, except that the anchor coat layer was formed by the following method. Specifically, an aqueous dispersion of polyolefin containing a carboxyl group salt (manufactured by Mitsui Chemicals, Inc., trade name: Chemipearl S100, particle size: less than 0.1 μm, solvent: water / IPA = 1 / 1 (mass ratio), solid content concentration: 20.0 mass%) was applied to the clay coat layer side surface of a paper substrate (thickness including the clay coat layer: 55 μm) using a bar coater, and dried in an oven to form an anchor coat layer with a thickness of 3 μm.

[0071] (Example 5) A laminate was obtained in the same manner as in Example 1, except that the overcoat layer was formed by the following method. Specifically, an aqueous dispersion of polyolefin containing a carboxyl group salt (manufactured by Mitsui Chemicals, Inc., trade name: Chemipearl S500, particle size: 0.7 μm, solvent: water / IPA = 1 / 1 (mass ratio), solid content concentration: 20.0 mass%) was coated onto the Al vapor-deposited layer with a bar coater and dried in an oven to form an overcoat layer with a thickness of 3 μm.

[0072] (Examples 6-7) A laminate was obtained in the same manner as in Example 1, except that the pressure inside the deposition chamber when forming the Al deposition layer was changed to the value shown in Table 1, and the thickness of the Al deposition layer was changed to the value shown in Table 1.

[0073] (Example 8) A laminate was obtained in the same manner as in Example 1, except that the anchor coat layer was formed by the following method. Specifically, a solution of polyvinyl alcohol (PVA) resin with a degree of saponification of 98% and a degree of polymerization of 500 dissolved in a solvent of water / IPA = 8 / 2 (mass ratio) at a solid content concentration of 10% by mass was applied to the surface of the clay coat layer side of a paper substrate (thickness including the clay coat layer: 55 μm) using a bar coater, and dried in an oven to form an anchor coat layer with a thickness of 3 μm.

[0074] (Example 9) A laminate was obtained in the same manner as in Example 8, except that the pressure inside the deposition chamber when forming the Al deposition layer was changed to the value shown in Table 2.

[0075] (Comparative Examples 1-2) A laminate was obtained in the same manner as in Example 1, except that the pressure inside the deposition chamber when forming the Al deposition layer was changed to the value shown in Table 2.

[0076] (Comparative Example 3) A laminate was obtained in the same manner as in Example 8, except that the pressure inside the deposition chamber when forming the Al deposition layer was changed to the value shown in Table 2.

[0077] <Preparation of paper substrate> The following clay-coated papers 1-3 and uncoated paper 4 were prepared as paper substrates. Clay coated paper 1: When changing from a temperature of 40°C and relative humidity of 20%RH to a temperature of 40°C and relative humidity of 90%RH, the dimensional change rates are CD=0.75%, MD=0.13%, and basis weight: 60g / m². 2 Clay coated paper 2: When changing from a temperature of 40°C and relative humidity of 20%RH to a temperature of 40°C and relative humidity of 90%RH, the dimensional change rates were CD=0.55%, MD=0.07%, and basis weight: 60g / m². 2 Clay coated paper 3: When changing from a temperature of 40°C and relative humidity of 20%RH to a temperature of 40°C and relative humidity of 90%RH, the dimensional change rates were CD=0.35%, MD=0.15%, and basis weight: 60g / m². 2 Uncoated paper 4: When changing from a temperature of 40°C and relative humidity of 20%RH to a temperature of 40°C and relative humidity of 90%RH, the dimensional change rates were CD=1.34%, MD=0.03%, and basis weight: 62g / m². 2

[0078] <Fabrication of laminates> (Example 10) Clay-coated paper 1 was prepared as the paper substrate. An aqueous dispersion of polyolefin containing a carboxyl group salt (manufactured by Sumitomo Seika Co., Ltd., product name: Zychsen AC, particle size: less than 0.2 μm, solvent: water / IPA = 1 / 1 (mass ratio), solid content concentration: 22.5 mass%) was applied to the clay-coated surface of the paper substrate using a gravure coater, and dried in an oven to form an anchor coat layer with a thickness of 3 μm.

[0079] Next, an Al deposition layer was formed on the anchor coat layer using a roll-to-roll induction heating vacuum deposition apparatus. The pressure inside the deposition chamber and the thickness of the Al deposition layer were adjusted to the values ​​shown in Table 3.

[0080] Next, an aqueous dispersion of polyolefin containing a carboxyl group salt (manufactured by Mitsui Chemicals, Inc., product name: Chemipearl S100, particle size: less than 0.1 μm, solvent: water / IPA = 1 / 1 (mass ratio), solid content concentration: 20.0 mass) was coated onto the Al vapor-deposited layer using a gravure coater and dried in an oven to form a 3 μm thick overcoat layer. This obtained a laminate.

[0081] (Example 11) A laminate was obtained in the same manner as in Example 10, except that the paper substrate was changed to clay-coated paper 2, and the pressure inside the deposition chamber and the thickness of the Al deposition layer during the formation of the Al deposition layer were changed to the values ​​shown in Table 3.

[0082] (Example 12) A laminate was obtained in the same manner as in Example 10, except that the Al vapor deposition layer was formed by the following method. Specifically, the Al vapor deposition layer was formed on the anchor coat layer using a roll-to-roll EB heating type vacuum deposition apparatus. The pressure inside the deposition chamber and the thickness of the Al vapor deposition layer were adjusted to the values ​​shown in Table 3.

[0083] (Example 13) A laminate was obtained in the same manner as in Example 12, except that the paper substrate was changed to clay-coated paper 2.

[0084] (Example 14) A laminate was obtained in the same manner as in Example 12, except that the paper substrate was changed to clay-coated paper 3.

[0085] (Example 15) Clay-coated paper 2 was prepared as the paper substrate. A solution of polyvinyl alcohol (Kuraray Co., Ltd., product name: Poval 5-98) with a degree of saponification of 98% and a degree of polymerization of 500, dissolved in a water / IPA = 8 / 2 (mass ratio) solvent at a solid content concentration of 10% by mass, was applied to the surface of the clay-coated layer of the paper substrate using a gravure coater, and dried in an oven to form an anchor coat layer with a thickness of 4 μm.

[0086] Next, an Al deposition layer was formed on the anchor coat layer using a roll-to-roll EB heating vacuum deposition apparatus. The pressure inside the deposition chamber and the thickness of the Al deposition layer were adjusted to the values ​​shown in Table 3.

[0087] Next, an aqueous dispersion of polyolefin containing a carboxyl group salt (manufactured by Mitsui Chemicals, Inc., product name: Chemipearl S500, particle size: 0.7 μm, solvent: water / IPA = 1 / 1 (mass ratio), solid content concentration: 20.0 mass%) was coated onto the Al vapor-deposited layer using a gravure coater and dried in an oven to form a 3 μm thick overcoat layer. This obtained a laminate.

[0088] (Example 16) A laminate was obtained in the same manner as in Example 15, except that the paper substrate was changed to clay-coated paper 1, and the pressure inside the deposition chamber and the thickness of the Al deposition layer during the formation of the Al deposition layer were changed to the values ​​shown in Table 3.

[0089] (Example 17) Uncoated paper 4 was prepared as the paper substrate. A solution of polyvinyl alcohol (Kuraray Co., Ltd., product name: Poval 5-98) with a degree of saponification of 98% and a degree of polymerization of 500, dissolved in a water / IPA = 8 / 2 (mass ratio) solvent at a solid content concentration of 10% by mass, was applied to one surface of the paper substrate using a gravure coater and dried in an oven to form an anchor coat layer with a thickness of 3 μm.

[0090] Subsequently, an Al vapor deposition layer was formed on the anchor coat layer using a roll-to-roll EB heating type vacuum deposition apparatus. The pressure in the deposition chamber during Al vapor deposition and the thickness of the Al vapor deposition layer were adjusted to the values shown in Table 4.

[0091] Next, an aqueous dispersion of ethylene-acrylic acid copolymer resin (manufactured by MICHELMAN, trade name: MC9100, solid content concentration: 20% by mass) was coated on the Al vapor deposition layer using a gravure coater and dried in an oven to form an overcoat layer with a thickness of 3 μm. Thus, a laminate was obtained.

[0092] (Comparative Examples 4 to 6) A laminate was obtained in the same manner as in Example 10, except that the pressure in the deposition chamber during formation of the Al vapor deposition layer and the thickness of the Al vapor deposition layer were changed to the values shown in Table 4.

[0093] (Comparative Example 7) A laminate was obtained in the same manner as in Example 12, except that the pressure in the deposition chamber during formation of the Al vapor deposition layer and the thickness of the Al vapor deposition layer were changed to the values shown in Table 4.

[0094] (Comparative Example 8) A laminate was obtained in the same manner as in Example 15, except that the pressure in the deposition chamber during formation of the Al vapor deposition layer and the thickness of the Al vapor deposition layer were changed to the values shown in Table 4.

[0095] <Measurement of the film thickness of the Al vapor deposition layer> The laminate was embedded in a UV curable resin and sectioned with a cryomicrotome to prepare a cross-sectional observation sample. The cross-section of this sample was observed with an electron microscope at a magnification of 50,000 times to obtain a SEM image. The thickness of the Al vapor deposition layer was measured from the obtained SEM image. The results are shown in Tables 1 to 4.

[0096] <X-ray diffraction measurement> The full width at half maximum (FWHM) of the peak of the (111) crystal plane of aluminum in the Al-deposited layer was measured using the following procedure. An X-ray diffractometer (product name: ATX-G) manufactured by Rigaku Electric Co., Ltd. was used for the FWHM measurement. CuKα rays were used as the light source, the tube voltage was 50kV, the tube current was 300mA, the optical system was a parallel beam optical system, the scanning method was the 2θ / θ method, the measurement range was 30° to 50°, and the scanning speed was 2° / min. The sampling step was 0.02°, and the slits were S1: 10.0mm × 1.0mm, S2: 10.0mm × 0.5mm, and Solar(res): 0.4mm. The laminates obtained in the examples and comparative examples were used as samples, and the paper substrate side was attached to a glass slide with double-sided tape for X-ray diffraction measurement. For the X-ray diffraction of aluminum, the FWHM of the peak at 2θ = 38.5° corresponding to the (111) plane (d = 2.34) was measured. The results are shown in Tables 1 to 4.

[0097] <Method for processing sample cross-sections> Samples for measuring the hardness and composite modulus of the anchor coat layer and overcoat layer were prepared from the cross-sections of the laminates obtained in the examples and comparative examples using the following procedure. First, the laminate was cut with a razor blade so that the sample containing the anchor coat layer and overcoat layer was in the shape of a strip or wedge, and the obtained sample was embedded in resin. D-800 photocurable resin manufactured by Toagosei Co., Ltd. was used as the embedding resin, and cured by light irradiation after embedding. The cured sample embedding resin was fixed with an AFM sample holder insert, and trimming and cross-sectional cutting of the film were performed with a glass knife at room temperature (25°C). Cross-sectional cutting was then performed with a diamond knife at a cutting speed of 1.0 mm / second and a cutting film thickness of 200 nm until a mirror finish was achieved. The cross-sectional samples were used for measurement by nanoindentation while fixed with an AFM sample holder insert. A Leica EMUC7 ultramicrotome was used as the cross-sectional cutting device. The cutting direction was parallel to the layer interface.

[0098] <Measurement of hardness and composite modulus> The hardness and complex elastic modulus of the anchor coat layer and the overcoat layer represent the hardness and complex elastic modulus calculated by the nanoindentation method. The nanoindentation method is a measurement method in which a quasi-static indentation test is performed on the target measurement object to obtain the mechanical properties of the sample. The measuring device used was the Hysitron TI-Premier (trade name) manufactured by Bruker Japan Co., Ltd. The indenter used was a Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. In the measurement by the nanoindentation method, first, a shape image of the sample was obtained by scanning the sample cross-section with a diamond indenter, and the measurement position of the desired layer was specified. Then, at room temperature (25 °C) in the displacement control mode, after indenting to a depth of 80 nm at an indenting speed of 80 nm / second, it was held for 1 second at the maximum depth, and then unloaded at a speed of 80 nm / second. The calculation method of the hardness and complex elastic modulus was to pre-test fused quartz as a standard sample and calibrate the relationship between the contact depth and the contact projected area of the indenter and the sample. Then, the unloading curve in the 60 - 95% region with respect to the maximum load during unloading was analyzed by the Oliver-Pharr method to calculate the hardness and complex elastic modulus. The results are shown in Tables 1 to 4.

[0099] <Measurement of elongation at break> For the measurement of the elongation at break of the anchor coat layer and the overcoat layer, the coating liquid for forming the anchor coat layer and the overcoat layer on the support substrate was applied and dried, then peeled off from the support substrate, punched into a dumbbell shape of type 1A to obtain test pieces, and measured based on the method described in JIS K7161. As the device, an autograph testing machine AGS-X (manufactured by Shimadzu Corporation) was used, the tensile test speed was 50 mm / min, and the measurement was performed in an environment of temperature 20 °C and humidity 65%. The results are shown in Tables 1 to 4.

[0100] <Measurement of KIT value> For the surface on the overcoat layer side of the laminates obtained in the examples and comparative examples, the oil resistance (KIT value) was measured by the TAPPI UM-557 method (kit method). Also, while rolling a 1500 g roller at a speed of 300 mm / min, a crease parallel to the MD direction was made in the laminate so that the laminate would form a valley fold when viewed from the paper base material side (with the overcoat layer on the outer surface), and the oil resistance (KIT value) of the crease part of the laminate after opening was also measured in the same manner. The KIT value is indicated by grades 0 to 12, and the higher the number, the higher the oil resistance. The highest oil resistance given by the KIT test liquid that does not show penetration was taken as the evaluation result. The KIT value is preferably 6 or more, and if it is less than 6, the oil resistance in food packaging may not be sufficient. The results are shown in Tables 1 to 4.

[0101] <Measurement of water vapor permeability> For the laminates obtained in the examples and comparative examples, the water vapor permeability (g / m 2 / day) under an atmosphere of 40°C and 90% RH was measured by the Mocon method in accordance with JIS K7129-2. For the measurement, a water vapor permeability measuring device (manufactured by MOCON, trade name: PERMATRAN-W3 / 34G) was used. Furthermore, after storing the laminate in a constant temperature and humidity chamber at 40°C and 90% RH for one week, the same measurement was performed. The water vapor permeabilities before and after storage at 40°C and 90% are shown in Tables 1 to 4.

[0102]

Table 1

[0103]

Table 2

[0104]

Table 3

[0105]

Table 4

[0106] As shown in Tables 1 to 4, the laminates of the examples exhibited good oil resistance (KIT value) not only initially but also after bending. Furthermore, as shown in Tables 1 to 4, the laminates of the examples maintained a water vapor permeability of 6 g / m² even after being stored at 40°C and 90% RH for one week. 2 The value was less than / d, confirming that good water vapor barrier properties can be maintained. [Explanation of symbols]

[0107] 1...Paper substrate, 2...Anchor coat layer, 3...Aluminum vapor deposition layer, 4...Overcoat layer, 10...Laminate, 20...Gusset bag, B1, B2...Folded section.

Claims

1. A laminate having a structure in which at least a paper substrate, an anchor coat layer, and an aluminum vapor deposition layer are laminated in this order, The aluminum vapor-deposited layer has a heat-sealable layer on its surface, The aluminum vapor-deposited layer has a full width at half maximum of the peak of the (111) crystal plane of aluminum in X-ray diffraction measurements of 1.6° or more and 15.0° or less. A laminate in which the anchor coat layer contains a polyolefin or polyvinyl alcohol-based resin having polar groups.

2. The laminate according to claim 1, wherein the hardness of the anchor coat layer, as measured by nanoindentation in a cross-section in the thickness direction of the laminate, is 0.3 GPa or less.

3. The laminate according to claim 1, wherein the thickness of the aluminum vapor deposition layer is 20 nm or more and 100 nm or less.

4. The laminate according to claim 1, wherein the thickness of the paper substrate is 20 μm or more and 100 μm or less.

5. The laminate according to claim 1, wherein the aluminum vapor-deposited layer is in contact with a resin layer containing an ionomer or a polyvinyl alcohol-based resin with a saponification degree of 95% or more.

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