Gas barrier laminate, and packaging bag and package using same

Abstract

A gas barrier laminate comprising a first polypropylene resin layer, a first gas barrier adhesive layer, an inorganic vapor deposition layer, a second polypropylene resin layer, and a sealant layer in this order from the outside to the inside.

Description

Gas barrier laminate, and packaging bag and packaging using the same

[0001] This disclosure relates to a gas barrier laminate, and to packaging bags and packaging materials using the same.

[0002] A laminate comprising a biaxially oriented PET (polyethylene terephthalate) film with excellent heat resistance and toughness as a base film, and a polyolefin film such as polyethylene or polypropylene as a sealant layer is known (see, for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2017-178357

[0004] To achieve even better gas barrier properties, a laminate is known that further comprises a vapor-deposited layer and a coating layer provided to cover it. The coating layer itself is a layer that has gas barrier properties and is formed using a coating solution containing, for example, tetraethoxysilane (TEOS). Figure 5 is a schematic cross-sectional view showing an example of a conventional gas barrier laminate. The gas barrier laminate 50 shown in this figure comprises an outermost layer 51 made of a resin film, an adhesive layer 52, a vapor-deposited substrate layer 53 made of a resin film, a vapor-deposited layer 54, a coating layer 55, an adhesive layer 56, and a sealant layer 57, in this order from the outside to the inside.

[0005] According to the inventors' studies, when a gas barrier laminate with the configuration shown in Figure 5 is placed under high temperature and high humidity conditions (for example, at a temperature of 30°C and a relative humidity of 70%), the oxygen permeability increases, and then decreases when placed under room temperature conditions (see Figure 6). When this gas barrier laminate is placed under high temperature and high humidity conditions again, the oxygen permeability increases again. From the results shown in Figure 6, it can be inferred that the oxygen barrier properties change reversibly between high temperature and high humidity conditions and room temperature conditions. In other words, when a laminate that has been confirmed to have high oxygen barrier properties at room temperature is used under high temperature and high humidity conditions, the expected oxygen barrier properties may not be exhibited. Note that "tropical conditions" in Figure 6 means that the outside of the gas barrier laminate is at a temperature of 30°C and a relative humidity of 70%, and "room temperature conditions" means that the outside of the gas barrier laminate is at a temperature of 23°C and a relative humidity of 50%. To protect the contents of a package that may be exposed to high temperature and high humidity conditions, it is considered necessary to use a laminate with higher oxygen barrier properties as the packaging material.

[0006] The inventors have created a laminate with the same configuration as the gas barrier laminate 50 shown in Figure 5, except that it includes an adhesive layer that has gas barrier properties and resistance to high temperature and high humidity conditions instead of a coating layer 55. Figure 7 is a schematic cross-sectional view of this laminate. The gas barrier laminate 60 shown in this figure comprises, in this order from the outside to the inside, an outermost layer 51 made of resin film, an adhesive layer 52, a vapor-deposited substrate layer 53 made of resin film, a vapor-deposited layer 54, a gas barrier adhesive layer 65, an adhesive layer 56, and a sealant layer 57. As a result of evaluating the gas barrier laminate 60, it was found that, with the improvement of oxygen barrier properties, the deterioration of many types of contents could be suppressed to a high degree even under high temperature and high humidity conditions, but the deterioration of some types of contents could not be sufficiently suppressed. Specifically, when the contents of the package were an acidic liquid, it was found that the contents had deteriorated when the package was opened after being stored for two months under high temperature and high humidity conditions. When the oxygen permeability of the packaging material (gas barrier laminate 60) after storage was measured, it was found to be higher than before storage, suggesting that the oxygen barrier properties of the packaging material were irreversibly reduced by the acidic contents. It is presumed that the contents underwent oxidative degradation along with the decrease in the oxygen barrier properties of the packaging material.

[0007] This disclosure is made in view of the above circumstances and provides a gas barrier laminate that has sufficient oxygen barrier properties under high temperature and high humidity conditions and can sufficiently suppress the deterioration of oxygen barrier properties over time even when containing acidic contents, as well as a packaging bag and packaging using the same.

[0008] One aspect of this disclosure relates to a gas barrier laminate. This gas barrier laminate comprises a first polypropylene resin layer, a first gas barrier adhesive layer, an inorganic vapor deposition layer, a second polypropylene resin layer, and a sealant layer, in this order from the outside to the inside.

[0009] In the gas barrier laminate according to this disclosure, the second polypropylene resin layer and the inorganic vapor-deposited layer are provided on the inside (contents side) of the first gas barrier adhesive layer. The second polypropylene resin layer and the inorganic vapor-deposited layer are thought to play a role in preventing acidic components contained in the contents from reaching the first gas barrier adhesive layer. This is presumed to be partly due to the fact that polypropylene resin has higher acid resistance compared to, for example, polyethylene resin. Specifically, it is presumed that polypropylene resin has steric hindrance due to the methyl groups present in its side chains and also has high intermolecular forces, which suppresses chemical reactions and interactions with acids. Furthermore, it is presumed that the higher degree of crystallinity of polypropylene resin compared to polyethylene resin, in other words, the denser molecular arrangement, contributes to the suppression of acidic component permeation. On the other hand, the inorganic vapor-deposited layer is less reactive with acidic components and is a barrier layer, so it is thought to play a role in preventing acidic components from reaching the first gas barrier adhesive layer. With the gas barrier laminate having the above layer configuration, even when acidic liquid contents are contained and stored for a long period in a high temperature and high humidity environment, the deterioration of oxygen barrier properties can be sufficiently suppressed.

[0010] The gas barrier laminate 60 shown in Figure 7 may have oxygen barrier properties equivalent to those of the gas barrier laminate according to the present disclosure in its initial state. However, when the oxygen barrier properties were evaluated after storing an acidic liquid contents in a packaging bag made from the gas barrier laminate 60 under high temperature and high humidity conditions for two months, the oxygen barrier properties had significantly decreased. This is presumed to be partly due to the fact that after the acid components permeate the sealant layer 57 and the adhesive layer 56, they reach the gas barrier adhesive layer 65, react with the components of the gas barrier adhesive, and as a result, the oxygen barrier properties of the gas barrier adhesive layer 65 decrease.

[0011] The gas barrier laminate according to this disclosure may further include a printed layer between the first polypropylene resin layer and the first gas barrier adhesive layer, and the printed layer may contain a curing agent. When the printed layer contains a curing agent, unreacted portions are less likely to remain when the printed layer is formed, so even if the first gas barrier adhesive layer is directly formed on the printed layer, components derived from the gas barrier adhesive are less likely to penetrate into the printed layer. As a result, the printed layer can fully exhibit adhesion to the first polypropylene resin layer, and the occurrence of delamination in the printed layer can be suppressed. The hardness of the printed layer can also be improved by including a curing agent in the printed layer. This is also presumed to contribute to the suppression of delamination in the printed layer. In other words, when a gas barrier laminate is heated by retort processing or the like after containing its contents, stress may be generated due to the difference in the thermal expansion coefficients of each layer constituting the gas barrier laminate. This stress may cause delamination in the printed layer. It is presumed that increasing the hardness of the printed layer with a curing agent reduces the difference in thermal expansion coefficients between the printed layer and the inorganic vapor-deposited layer, thereby reducing the stress after heating.

[0012] The printed layer may have a medium layer on the surface facing the first gas barrier adhesive layer. That is, the printed layer may have an ink layer and a medium layer provided so as to cover the ink layer. The medium layer protects the ink layer and also has the effect of smoothing the surface of the printed layer. The medium layer may consist of, for example, a binder component contained in the ink layer.

[0013] The gas barrier laminate according to this disclosure may have a first gas barrier adhesive layer composed of a cured epoxy adhesive. Because epoxy resins easily form dense films due to their molecular structure, a first gas barrier adhesive layer made of a cured epoxy adhesive tends to exhibit higher gas barrier properties.

[0014] The gas barrier laminate according to this disclosure may have an inorganic vapor-deposited layer directly provided on the surface of the second polypropylene resin layer. The second polypropylene resin layer may have a treatment applied to the surface on which the inorganic vapor-deposited layer is provided to improve adhesion of the inorganic vapor-deposited layer, or an anchor coat may be formed thereon.

[0015] The gas barrier laminate according to this disclosure further comprises an adhesive layer between the second polypropylene resin layer and the sealant layer, and the adhesive layer may be made of an epoxy resin or a urethane resin.

[0016] The gas barrier laminate according to this disclosure may further include a second gas barrier adhesive layer between the second polypropylene resin layer and the sealant layer. In this case, the oxygen permeability of the gas barrier laminate becomes lower, so the gas barrier laminate can be applied to applications requiring stricter oxygen barrier properties.

[0017] One aspect of this disclosure is a packaging bag made by forming the above-mentioned gas barrier laminate into a bag. Another aspect of this disclosure is a packaging body comprising a packaging bag and contents contained in the packaging bag.

[0018] The present disclosure provides a gas barrier laminate that has sufficient oxygen barrier properties under high temperature and high humidity conditions and can sufficiently suppress the deterioration of its oxygen barrier properties over time even when it contains acidic contents, as well as a packaging bag and packaging using the same.

[0019] Figure 1 is a schematic cross-sectional view showing a gas barrier laminate according to the first embodiment. Figure 2 is a schematic cross-sectional view showing a gas barrier laminate according to the second embodiment. Figure 3 is a schematic cross-sectional view showing a gas barrier laminate according to the third embodiment. Figure 4 is a schematic cross-sectional view showing one embodiment of the packaging according to the present disclosure. Figure 5 is a schematic cross-sectional view showing an example of a conventional gas barrier laminate. Figure 6 shows the oxygen permeability [cc / m³] of the laminate according to Figure 5 under tropical conditions and room temperature conditions. ２ This is a graph showing the day atm (OTR). Figure 7 is a schematic cross-sectional view showing an example of a gas barrier laminate in which the stacking order of the gas barrier laminate shown in Figure 5 has been changed.

[0020] The embodiments of this disclosure will be described below, with reference to the drawings as appropriate. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted. Furthermore, the dimensional ratios in the drawings are not limited to those shown.

[0021] [Gas Barrier Laminate] Figure 1 is a schematic cross-sectional view of a gas barrier laminate according to the first embodiment. The gas barrier laminate 10 shown in this figure comprises, in this order, a first polypropylene resin layer 1, a first gas barrier adhesive layer 2, an inorganic vapor deposition layer 3, a second polypropylene resin layer 4, and a sealant layer 5. In the gas barrier laminate 10, the sealant layer 5 side is the inside, and the first polypropylene resin layer 1 side is the outside. The sealant layer 5 may constitute the inner outermost surface of the gas barrier laminate 10. The first polypropylene resin layer 1 may constitute the outer outermost surface of the gas barrier laminate. That is, in the gas barrier laminate 10, the sealant layer 5 and the first polypropylene resin layer 1 may each be exposed.

[0022] The gas barrier laminate 10 may have the following layer configuration: a first polypropylene resin layer, a first gas barrier adhesive layer, an inorganic vapor deposition layer, a second polypropylene resin layer, and a sealant layer. The gas barrier laminate 10 may consist only of the layers shown in the above layer configuration. That is, adjacent layers in the above layer configuration may be in direct contact with each other.

[0023] Figure 2 is a schematic cross-sectional view of a gas barrier laminate according to the second embodiment. The gas barrier laminate 20 shown in this figure differs from the gas barrier laminate 10 in the following respects: - It further comprises a printed layer 6 between the first polypropylene resin layer 1 and the first gas barrier adhesive layer 2. - It further comprises an adhesive layer 7 between the second polypropylene resin layer 4 and the sealant layer 5.

[0024] The gas barrier laminate 20 may have any of the following layer configurations: • First polypropylene resin layer / printed layer / first gas barrier adhesive layer / inorganic vapor deposition layer / second polypropylene resin layer / adhesive layer / sealant layer • First polypropylene resin layer / printed layer / first gas barrier adhesive layer / inorganic vapor deposition layer / second polypropylene resin layer / sealant layer • First polypropylene resin layer / first gas barrier adhesive layer / inorganic vapor deposition layer / second polypropylene resin layer / adhesive layer / sealant layer The gas barrier laminate 20 may have only the layers shown in the above layer configurations. That is, adjacent layers in the above layer configurations may be in direct contact with each other.

[0025] Figure 3 is a schematic cross-sectional view of a gas barrier laminate according to the third embodiment. The gas barrier laminate 30 shown in this figure differs from the gas barrier laminate 10 in the following respects: - It further comprises a printed layer 6 between the first polypropylene resin layer 1 and the first gas barrier adhesive layer 2. - The printed layer 6 has a medium layer 6a on the surface facing the first gas barrier adhesive layer 2. - The second polypropylene resin layer 4 has an anchor coat 4a on the surface where the inorganic vapor deposition layer 3 is provided. - It further comprises a second gas barrier adhesive layer 8 between the second polypropylene resin layer 4 and the sealant layer 5.

[0026] The gas barrier laminate 30 may have the following layer configurations: • First polypropylene resin layer / Printed layer / First gas barrier adhesive layer / Inorganic vapor deposition layer / Anchor coat layer / Second polypropylene resin layer / Second gas barrier adhesive layer / Sealant layer • First polypropylene resin layer / Printed layer / First gas barrier adhesive layer / Inorganic vapor deposition layer / Anchor coat layer / Second polypropylene resin layer / Adhesive layer / Sealant layer • First polypropylene resin layer / Printed layer / First gas barrier adhesive layer / Inorganic vapor deposition layer / Second polypropylene resin layer / Second gas barrier adhesive layer / Sealant layer The gas barrier laminate 30 may have only the layers shown in the above layer configuration. That is, adjacent layers in the above layer configuration may be in direct contact with each other.

[0027] The gas barrier laminate according to this disclosure only needs to include a first polypropylene resin layer, a first gas barrier adhesive layer, an inorganic vapor deposition layer, a second polypropylene resin layer, and a sealant layer in this order from the outside to the inside, and any combination of other layers can be adopted. Layers that are provided in the gas barrier laminate 20 or gas barrier laminate 30 but not in the gas barrier laminate 10 (printing layer 6, medium layer 6a, adhesive layer 7, anchor coat 4a, and second gas barrier adhesive layer 8, etc.) may be provided in the gas barrier laminate 10 individually or in combination of two or more. In this case, the printing layer 6, adhesive layer 7, anchor coat 4a, and second gas barrier adhesive layer 8 can each independently exhibit the effects described later.

[0028] The following explains each layer.

[0029] [First Polypropylene Resin Layer] The first polypropylene resin layer 1 is a layer containing polypropylene resin. The polypropylene resin content in the first polypropylene resin layer 1 may be 50% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass, based on the total amount of the first polypropylene resin layer 1. The first polypropylene resin layer 1 may also contain polypropylene resin derived from biomass or recycled from products.

[0030] The polypropylene resin may be homopolypropylene or propylene copolymer. From the viewpoint of adhesion and barrier properties, a coating layer such as an easy-adhesion layer containing propylene copolymer may be provided on the lamination surface (the side on which the first gas barrier adhesive layer 2 is laminated) of the first polypropylene resin layer 1 with the first gas barrier adhesive layer 2. The easy-adhesion layer can be provided between the first polypropylene resin layer 1 and the first gas barrier adhesive layer 2.

[0031] The density of the polypropylene resin contained in the first polypropylene resin layer 1 is 0.88 g / cm³. ３ It may be greater than or equal to 0.89 g / cm³. ３ It may be greater than or equal to 0.90 g / cm³. ３may be 0.92 g / cm ３ or higher. Further, the density may be 0.93 g / cm ３ or lower, and may be 0.92 g / cm ３ or lower, and may be 0.91 g / cm ３ or lower. The density may be 0.88 to 0.93 g / cm ３ , 0.89 to 0.93 g / cm ３ , 0.90 to 0.93 g / cm ３ , 0.92 to 0.93 g / cm ３ , 0.88 to 0.92 g / cm ３ , 0.89 to 0.92 g / cm ３ , 0.90 to 0.92 g / cm ３ , 0.88 to 0.91 g / cm ３ , 0.89 to 0.91 g / cm ３ , or 0.90 to 0.91 g / cm ３ When the density is 0.88 g / cm ３ or higher, it is easy to suppress stretching and wrinkling of the first polypropylene resin layer 1 during roll processing, and it is also easy to suppress cracking of the inorganic vapor deposition layer 3.

[0032] The configuration of the first polypropylene resin layer 1 may be a multilayer configuration including a layer (film) containing a polypropylene resin and a plurality of layers (films) each containing a polyolefin having a density different from that of the layer. It is desirable that the first polypropylene resin layer 1 is appropriately formed into a multilayer structure in consideration of processability, rigidity, stiffness, heat resistance, powder falling during conveyance, and the like of the film constituting the first polypropylene resin layer 1. When the film constituting the first polypropylene resin layer 1 includes a plurality of layers, the first polypropylene resin layer 1 may have an adhesive resin layer. The adhesive resin layer may be disposed on the outermost surface of the first polypropylene resin layer 1, or may be disposed on the inner side. The adhesive resin layer may contain maleic anhydride-modified polypropylene such as maleic acid grafted homopolypropylene.

[0033] If the film constituting the first polypropylene resin layer 1 comprises multiple layers, the content of slip agents, antistatic agents, etc., may be varied in each layer during lamination. The first polypropylene resin layer 1 comprising multiple layers can be laminated into a film by extrusion coating, co-extrusion coating, sheet molding, co-extrusion blow molding, etc. The total thickness of the first polypropylene resin layer 1 comprising multiple layers may be 10 to 100 μm, 15 to 100 μm, 10 to 50 μm, or 15 to 50 μm.

[0034] A polypropylene resin film may be used as the first polypropylene resin layer 1. The polypropylene resin film may be a stretched film or an unstretched film. However, from the viewpoint of impact resistance, heat resistance, water resistance, dimensional stability, and ease of tearing, the first polypropylene resin layer 1 may be a stretched film. When a printing layer 6, described later, is provided on the first polypropylene resin layer 1, a stretched film has the advantage of being easier to print on. Also, if the first polypropylene resin layer 1 is a stretched film, the gas barrier laminate can be suitably used for applications involving retort processing or boiling processing. The stretching method is not particularly limited, and any method is acceptable as long as a dimensionally stable film can be supplied, such as stretching by inflation, uniaxial stretching, or biaxial stretching.

[0035] The thickness of the first polypropylene resin layer 1 is not particularly limited. Depending on the application, the thickness can be 6 to 200 μm, but from the viewpoint of obtaining excellent impact resistance and excellent gas barrier properties, it may be 6 to 50 μm, 6 to 38 μm, 9 to 200 μm, 9 to 50 μm, 9 to 38 μm, 12 to 200 μm, 12 to 50 μm, or 12 to 38 μm.

[0036] The first polypropylene resin layer 1 may be subjected to various pretreatments such as corona treatment, plasma treatment, low-temperature plasma treatment, flame treatment, chemical treatment, solvent treatment, or ozone treatment on its laminated surface, to the extent that it does not impair barrier performance, or a coating layer such as an easy-adhesion layer may be provided.

[0037] The first polypropylene resin layer 1 may contain additives such as fillers, antiblocking agents, antistatic agents, plasticizers, lubricants, and antioxidants. These additives may be used individually or in combination of two or more.

[0038] [First Gas Barrier Adhesive Layer] The first gas barrier adhesive layer 2 is a layer made of a cured gas barrier adhesive. The first gas barrier adhesive layer 2 adheres the inorganic vapor deposition layer 3 and the first polypropylene resin layer 1, protects the inorganic vapor deposition layer 3, and prevents cracking of the inorganic vapor deposition layer 3 when the gas barrier laminate 10 deforms. As shown in Figures 1 to 3, the first gas barrier adhesive layer 2 is positioned between the first polypropylene resin layer 1 and the inorganic vapor deposition layer 3, and is located outside the inorganic vapor deposition layer 3 and the second polypropylene resin layer 4. By positioning the first gas barrier adhesive layer 2 in this location, a higher oxygen barrier property can be maintained even after long-term storage in a high-temperature, high-humidity environment compared to the case where the first gas barrier adhesive layer 2 is positioned between the inorganic vapor deposition layer 3 and the sealant layer 5. In addition, depending on the type of first gas barrier adhesive layer 2, an off-odor, presumably caused by retort processing, may be generated and transferred to the contents. Such phenomena can also be suppressed by the placement of the first gas barrier adhesive layer 2 at this position.

[0039] The first gas barrier adhesive layer 2 is a gas barrier layer. The oxygen permeability of the first gas barrier adhesive layer 2 is 150 cc / m³. ２ ・day・atm or less, 100cc / m ２ ・day・atm or less, 80cc / m ２ ・day・atm or less or 50cc / m ２ - It may be less than or equal to day·atm. By keeping the oxygen permeability within the above range, the gas barrier properties of the gas barrier laminate 10 can be sufficiently improved, and even if minor cracks occur in the inorganic vapor deposition layer 3, the first gas barrier adhesive layer 2 can fill the gaps and compensate for them, thereby suppressing a decrease in the gas barrier properties of the gas barrier laminate 10.

[0040] The first gas barrier adhesive layer 2 is formed using a gas barrier adhesive that exhibits gas barrier properties after curing. Examples of adhesives used to form the first gas barrier adhesive layer 2 (first gas barrier adhesive) include epoxy adhesives and polyester / polyurethane adhesives. Specific examples of adhesives that exhibit gas barrier properties after curing include "Maxieve" manufactured by Mitsubishi Gas Chemical Company and "Paslim" manufactured by DIC Corporation.

[0041] The mass per unit area of ​​the first gas barrier adhesive layer is 1.65 g / m². ２ Above, 1.75g / m ２ Above, 2.0g / m ２ Above, 2.75g / m ２ Above, or 3.0 g / m ２ The above is acceptable. The above mass is 7.0 g / m ２ Below, 5.0g / m ２ The following, or 4.0 g / m ２ The following is acceptable: The above mass is 1.65 to 7.0 g / m ２ , 1.75-7.0g / m ２ , 2.0-7.0g / m ２ , 2.75-7.0g / m ２ , 3.0-7.0g / m ２ , 1.65-5.0g / m ２ , 1.75-5.0g / m ２ , 2.0~5.0g / m ２ , 2.75-5.0g / m ２ , 3.0-5.0g / m ２ , 1.65-4.0g / m ２ , 1.75-4.0g / m ２ , 2.0-4.0g / m ２ , 2.75-4.0g / m ２ , or 3.0-4.0 g / m ２ That's fine.

[0042] When the gas barrier adhesive layer and the ink layer are in contact, bubbly delamination (lifting) may occur between the gas barrier adhesive and the ink layer. The mass per unit area of ​​the gas barrier adhesive layer is 1.65 g / m². ２As a result, the adhesion between the printed layer and the first gas barrier adhesive layer 2 is improved, and the occurrence of blister-like delamination between them is suppressed. Furthermore, the above mass is 2.75 g / m². ２ In the above cases, the above effects will be more pronounced.

[0043] The thickness of the first gas barrier adhesive layer 2 may be 50 times or more the thickness of the inorganic vapor deposition layer 3. Having the thickness of the first gas barrier adhesive layer 2 within this range allows for more effective suppression of cracking of the inorganic vapor deposition layer 3 and further improves the gas barrier properties of the gas barrier laminate 10. Furthermore, having the thickness of the first gas barrier adhesive layer 2 within this range provides cushioning to mitigate external impacts, preventing the inorganic vapor deposition layer 3 from cracking due to impact. On the other hand, from the viewpoint of maintaining the flexibility of the gas barrier laminate 10, processability, and cost, the thickness of the first gas barrier adhesive layer 2 may be 300 times or less the thickness of the inorganic vapor deposition layer 3.

[0044] The thickness of the first gas barrier adhesive layer 2 may be 0.1 to 20 μm, 0.5 to 20 μm, 1 to 20 μm, 0.1 to 10 μm, 0.5 to 10 μm, 1 to 10 μm, 0.1 to 5 μm, 0.5 to 5 μm, or 1 to 5 μm. When the thickness of the first gas barrier adhesive layer 2 is greater than or equal to the lower limit, cracking of the inorganic vapor deposition layer 3 can be suppressed more effectively, and the gas barrier properties of the gas barrier laminate 10 can be further improved. Also, when the thickness of the first gas barrier adhesive layer 2 is greater than or equal to the lower limit, cushioning properties that mitigate external impacts can be obtained, preventing the inorganic vapor deposition layer 3 from cracking due to impact. On the other hand, when the thickness of the first gas barrier adhesive layer 2 is less than or equal to the upper limit, the flexibility of the gas barrier laminate 10 tends to be sufficiently maintained.

[0045] The first gas barrier adhesive layer 2 can be formed by a process of applying a gas barrier adhesive. Examples of application methods include bar coating, dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, and gravure offset. The temperature for drying the gas barrier adhesive coating may be, for example, 30 to 200°C, 30 to 180°C, 50 to 200°C, or 50 to 180°C. The temperature for curing the coating may be, for example, room temperature to 70°C, 30 to 70°C, room temperature to 60°C, or 30 to 60°C. By keeping the drying and curing temperatures within the above ranges, crack formation in the inorganic vapor deposition layer 3 and the first gas barrier adhesive layer 2 can be further suppressed, and excellent gas barrier properties can be achieved.

[0046] From the viewpoint of preventing cracking of the inorganic vapor-deposited layer 3, the first gas barrier adhesive layer 2 may be in direct contact with the inorganic vapor-deposited layer 3. That is, there does not need to be any other layer between the first gas barrier adhesive layer 2 and the inorganic vapor-deposited layer 3. For this reason, the first gas barrier adhesive layer 2 may be formed by applying the gas barrier adhesive onto the inorganic vapor-deposited layer 3, drying and curing it. The first gas barrier adhesive layer 2 may be in direct contact with the first polypropylene resin layer 1, or there may be another layer interposed between the first polypropylene resin layer 1 and the first gas barrier adhesive layer 2.

[0047] [Inorganic Vapor Deposition Layer] The inorganic vapor deposition layer 3 is an inorganic film. Examples of constituent materials for the inorganic vapor deposition layer 3 include inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide, or metals such as aluminum and stainless steel. From the viewpoint of transparency and barrier properties, the inorganic oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide.

[0048] From the viewpoint of tensile stretchability during processing of the gas barrier laminate, the constituent material of the inorganic vapor-deposited layer 3 may be silicon oxide. The O / Si ratio of the inorganic vapor-deposited layer 3 may be 1.7 or higher. When the O / Si ratio is 1.7 or higher, the content of metallic Si is suppressed, making it easier to obtain good transparency. Alternatively, the O / Si ratio may be 2.0 or lower. When the O / Si ratio is 2.0 or lower, the crystallinity of SiO is increased, which prevents the inorganic vapor-deposited layer 3 from becoming too hard, and good tensile strength can be obtained. This makes it possible to suppress the occurrence of cracks in the inorganic vapor-deposited layer 3 when laminating the first gas barrier adhesive layer 2. Furthermore, when the packaging bag 100 made by forming the gas barrier laminate 10 is subjected to retort or boiling treatment, the second polypropylene resin layer 4 may shrink due to heat. In this case, an O / Si ratio of 2.0 or lower makes it easier for the inorganic vapor-deposited layer 3 to follow the above shrinkage, and a decrease in barrier properties can be suppressed. From the viewpoint of obtaining these effects more fully, the O / Si ratio of the inorganic vapor deposition layer 3 may be 1.7 or more and 2.0 or less, 1.7 or more and 1.9 or less, 1.7 or more and 1.85 or less, 1.75 or more and 2.0 or less, 1.75 or more and 1.9 or less, 1.75 or more and 1.85 or less, 1.8 or more and 2.0 or less, 1.8 or more and 1.9 or less, or 1.8 or more and 1.85 or less.

[0049] The O / Si ratio of the inorganic vapor-deposited layer 3 can be determined by X-ray photoelectron spectroscopy (XPS). For example, the measurement can be performed using an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV), with a non-monochromatic MgKα (1253.6 eV) X-ray source and an X-ray output of 100 W (10 kV - 10 mA). For quantitative analysis to determine the O / Si ratio, relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p can be used.

[0050] The film thickness of the inorganic vapor-deposited layer 3 may be between 10 nm and 50 nm. A film thickness of 10 nm or more provides sufficient gas barrier properties. A film thickness of 50 nm or less suppresses the occurrence of cracks in the inorganic vapor-deposited layer 3 due to deformation caused by internal stress. This suppresses a decrease in the gas barrier properties of the gas barrier laminate 10. Furthermore, from an economic standpoint, the film thickness may be 50 nm or less, as this makes it easier to suppress cost increases due to increased material usage and longer film formation times. From the same viewpoint as above, the film thickness of the inorganic vapor-deposited layer 3 may be between 20 nm and 40 nm.

[0051] The inorganic vapor deposition layer 3 can be formed, for example, by vacuum deposition. For vacuum deposition, physical vapor deposition or chemical vapor deposition can be used. Examples of physical vapor deposition include vacuum deposition, sputtering, and ion plating, but are not limited to these. Examples of chemical vapor deposition include thermal CVD, plasma CVD, and photo-CVD, but are not limited to these.

[0052] The vacuum deposition methods described above include resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD). However, considering productivity, vacuum deposition is currently the most superior method. For the heating method of vacuum deposition, electron beam heating, resistance heating, or induction heating may be used. The inorganic deposition layer 3 may be provided in direct contact with the second polypropylene resin layer 4.

[0053] [Second Polypropylene Resin Layer] The second polypropylene resin layer 4 is a support film and includes a polypropylene resin film. As the polypropylene resin film, the same polypropylene film as the first polypropylene resin layer 1 can be used. The second polypropylene resin layer 4 may have an anchor coat 4a provided on the surface of the polypropylene film (see Figure 3).

[0054] If the film constituting the second polypropylene resin layer 4 comprises multiple layers, the second polypropylene resin layer 4 may include an adhesive resin layer. The adhesive resin layer may be placed on the outermost surface of the second polypropylene resin layer 4. The adhesive resin layer may include maleic anhydride-modified polypropylene such as maleic acid-grafted homopolypropylene. By placing the adhesive resin layer on the outermost surface of the second polypropylene resin layer 4, the second polypropylene resin layer 4 and adjacent layers are well adhered to each other.

[0055] The second polypropylene resin layer 4 may further have a surface layer on the surface facing the inorganic vapor deposition layer 3. In this case, the second polypropylene resin layer 4, the surface layer, and the inorganic vapor deposition layer 3 are laminated in this order. If an anchor coat layer is present on the second polypropylene resin layer 4, the surface layer may be placed between the second polypropylene resin layer 4 and the anchor coat layer.

[0056] The surface layer may contain a high-melting-point resin having a melting point of 150°C or higher. In this case, the expansion and contraction of the second polypropylene resin layer 4 are reduced, and the expansion and contraction of the inorganic vapor-deposited layer 3 can be prevented. This further enhances the gas barrier properties of the gas barrier laminates 10, 20, and 30. The melting point can be measured using a differential scanning calorimeter (DSC) with a heating rate of 10°C / min. From the viewpoint of film-forming properties of the surface layer, the melting point of the high-melting-point resin may be 190°C or lower. The above melting point may be between 150°C and 190°C.

[0057] High-melting-point resins can be any resin with a melting point of 150°C or higher. Examples of high-melting-point resins include vinyl resins, polyamide resins, polyimide resins, polyester resins, and cellulose resins. These may be used individually or in combination of two or more. Examples of vinyl resins include ethylene vinyl alcohol (EVOH). The ethylene content (mol%) in EVOH may be, for example, 25 mol% to 50 mol%. Examples of polyamide resins include nylon 6 and nylon 6,6. Examples of polyester resins include polyethylene terephthalate.

[0058] The surface layer may be formed by co-extrusion together with the second polypropylene resin layer 4, or it may be formed by coating the second polypropylene resin layer 4.

[0059] (Anchor Coat) The anchor coat 4a can provide effects such as improving the adhesion performance between the second polypropylene resin layer 4 and the inorganic vapor-deposited layer 3, improving the smoothness of the surface of the second polypropylene resin layer 4, and suppressing the occurrence of cracks in the inorganic vapor-deposited layer 3 caused by the elongation of the second polypropylene resin layer 4. By improving the smoothness of the second polypropylene resin layer 4, it becomes easier to deposit the inorganic vapor-deposited layer 3 uniformly without defects, and it is easier to exhibit high barrier properties. The anchor coat 4a can be formed using an anchor coat agent. That is, the anchor coat 4a is a cured product of the anchor coat agent. From the viewpoint of preventing cracks in the inorganic vapor-deposited layer 3, the inorganic vapor-deposited layer 3 may be in direct contact with the anchor coat 4a.

[0060] Examples of resins used in anchor coating agents include acrylic resins, epoxy resins, acrylic urethane resins, polyester polyurethane resins, and polyether polyurethane resins. The resin used in the anchor coating agent may be an acrylic urethane resin or a polyester polyurethane resin, from the viewpoint of heat resistance and interlayer adhesion strength. An anchor coat 4a can be formed using these resins, or an anchor coating agent containing components that react to form these resins.

[0061] The thickness of the anchor coat 4a is not particularly limited, but may be in the range of 0.095 to 5 μm, 0.01 to 5 μm, 0.03 to 5 μm, 0.095 to 3 μm, 0.01 to 3 μm, 0.03 to 3 μm, 0.095 to 2 μm, 0.01 to 2 μm, or 0.03 to 2 μm. When the thickness of the anchor coat 4a is greater than or equal to the lower limit, a more sufficient interlayer adhesion strength tends to be obtained, while when it is less than or equal to the upper limit, the desired gas barrier properties tend to be more easily exhibited.

[0062] As for the method of coating the anchor coat 4a onto the second polypropylene resin layer 4, known coating methods can be used without particular limitation, including dipping methods; spray, coater, printing press, brush, etc. Furthermore, as for the types of coaters and printing presses used in these methods and their coating methods, examples include gravure coaters such as direct gravure, reverse gravure, kiss reverse gravure, and offset gravure, reverse roll coaters, microgravure coaters, chamber doctor combined coaters, air knife coaters, dip coaters, bar coaters, comma coaters, die coaters, etc.

[0063] The amount of anchor coat 4a to be applied should be such that the mass per unit area after the anchor coat agent has been applied and dried is 0.01 to 5 g / m². ２ ,0.03~5g / m ２ ,0.01~3g / m ２ ,0.03~3g / m ２ This may be the case. If the mass per unit area of ​​the anchor coat 4a after coating and drying the anchor coat agent is above the above lower limit, the film formation tends to be sufficient, while if it is below the above upper limit, it tends to dry sufficiently and less solvent residue is likely to remain.

[0064] The method for drying the anchor coat 4a is not particularly limited, but examples include natural drying, drying in an oven set to a predetermined temperature, and using a dryer attached to the coater, such as an arch dryer, floating dryer, drum dryer, or infrared dryer. Furthermore, the drying conditions can be appropriately selected depending on the drying method. For example, in the case of drying in an oven, drying may be done at a temperature of 60 to 100°C for about 1 second to 2 minutes.

[0065] As the anchor coat 4a, a polyvinyl alcohol-based resin may be used instead of the resin described above. The polyvinyl alcohol-based resin can be any resin having vinyl alcohol units formed by saponification of vinyl ester units, such as polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH).

[0066] Examples of PVA include resins obtained by polymerizing vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versaticate individually, and then saponifying them. The PVA may also be copolymerized or post-modified modified PVA. Modified PVA can be obtained, for example, by copolymerizing a vinyl ester with an unsaturated monomer copolymerizable with the vinyl ester, followed by saponification. Examples of unsaturated monomers copolymerizable with vinyl esters include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 4-pentin-1-ol, and 5-hexen-1-ol; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecylenic acid; nitriles such as acrylonitrile and methacrylonitrile; diacetone acrylamide, acrylic acid Examples include amides such as luamide and methacrylamide; olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and metaallyl sulfonic acid; vinyl compounds such as alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride, vinylethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxolane, glycerin monoallyl ether, and 3,4-diacetoxy-1-butene; and vinylidene chloride, 1,4-diacetoxy-2-butene, vinylene carbonate, etc.

[0067] The degree of polymerization of PVA may be 300 to 3000. A degree of polymerization of 300 or higher tends to improve barrier properties, while a degree of polymerization of 3000 or lower tends to suppress the decrease in coating suitability due to excessively high viscosity. The degree of saponification of PVA may be 90 mol% or higher, 95 mol% or higher, or 99 mol% or higher. Furthermore, the degree of saponification of PVA may be 100 mol% or lower, or 99.9 mol% or lower. The degree of saponification of PVA may be 90 to 100 mol%, 90 to 99.9 mol%, 95 to 100 mol%, or 95 to 99.9 mol%. The degree of polymerization and degree of saponification of PVA can be measured in accordance with the method described in JIS K 6726 (1994).

[0068] EVOH is generally obtained by saponifying copolymers of ethylene with vinyl acid esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate.

[0069] The degree of polymerization of EVOH may be 300 to 3000. A degree of polymerization of 300 or higher tends to improve barrier properties, while a degree of polymerization of 3000 or lower tends to suppress the decrease in coating suitability due to excessively high viscosity. The degree of saponification of the vinyl ester component of EVOH may be 90 mol% or higher, 95 mol% or higher, or 99 mol% or higher. Furthermore, the degree of saponification of the vinyl ester component of EVOH may be 100 mol% or lower, or 99.9 mol% or lower. The degree of saponification of the vinyl ester component of EVOH may be 90 to 100 mol%, 90 to 99.9 mol%, 95 to 100 mol%, or 95 to 99.9 mol%. The degree of saponification of the vinyl ester component of EVOH is determined by nuclear magnetic resonance ( １ The hydrogen atom is determined by performing a 1H-NMR (H-NMR) measurement and comparing the peak area of ​​hydrogen atoms in the vinyl ester structure with the peak area of ​​hydrogen atoms in the vinyl alcohol structure.

[0070] The ethylene unit content of EVOH is 10 mol% or more, and may be 15 mol% or more, 20 mol% or more, or 25 mol% or more. Alternatively, the ethylene unit content of EVOH may be 65 mol% or less, 55 mol% or less, or 50 mol% or less. An ethylene unit content of 10 mol% or more allows for good gas barrier properties or dimensional stability under high humidity conditions. On the other hand, an ethylene unit content of 65 mol% or less enhances gas barrier properties. The ethylene unit content of EVOH can be determined by the NMR method.

[0071] When a polyvinyl alcohol-based resin is used as the anchor coat 4a, methods for forming the anchor coat 4a include coating with a polyvinyl alcohol-based resin solution and multilayer extrusion. [Sealant layer] The sealant layer 5 is a layer that provides heat sealing properties to the gas barrier laminates 10, 20, and 30. The sealant layer 5 may be made of a polyolefin film. The polyolefin may include polypropylene or polyethylene. The sealant layer 5 may be made of a polypropylene film or a polyethylene film. The sealant layer 5 constitutes the surface of the gas barrier laminates 10, 20, and 30. That is, the sealant layer 5 may be placed on the outermost surface of the gas barrier laminates 10, 20, and 30 and may be a layer exposed to the outside of the gas barrier laminates 10, 20, and 30.

[0072] As the material for the sealant layer 5, polyolefin resins among thermoplastic resins are generally used. Specifically, ethylene resins 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 can be used, as well as polyethylene and polybutene blend resins, homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer. These thermoplastic resins can be appropriately selected depending on the intended use of the gas barrier laminate 10 and temperature conditions such as boiling treatment.

[0073] The sealant layer 5 may contain various additives such as flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers.

[0074] The thickness of the sealant layer 5 is determined by the mass of the contents contained in the packaging bag 100 made from the gas barrier laminate 10, the shape of the packaging bag 100, etc., but it can generally be 30 to 150 μm thick.

[0075] Methods for forming the sealant layer 5 include known lamination methods such as a method of bonding film-like sealant layers 5 made of the thermoplastic resin described above by a dry lamination method, or a method of heating and melting the thermoplastic resin described above and co-extruding it with the second polypropylene resin layer 4. Examples of adhesives used in the dry lamination method include an adhesive for forming the adhesive layer 7, as described later, or a second gas barrier adhesive for forming the second gas barrier adhesive layer 8. When the sealant layer 5 is formed by co-extrusion or the like, the sealant layer 5 may be directly laminated on the surface of the second polypropylene resin layer 4.

[0076] [Printed Layer] The printed layer 6 is provided in a position visible from the outside of the gas barrier laminates 10, 20, and 30 for the purpose of displaying information about the contents, identifying the contents, or improving the design of the packaging bag 100. The printing method and printing ink are not particularly limited and are appropriately selected from known printing methods and printing inks, taking into consideration factors such as suitability for printing on the film, design aspects such as color tone, adhesion, and safety as a food container. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. Among these, gravure printing may be used from the viewpoint of productivity and high resolution of the image. From the viewpoint of environmental considerations, biomass inks or biodegradable inks may be used as inks, and water-soluble solvents such as water or alcohol may be used as solvents.

[0077] The lamination position of the printed layer 6 is not particularly limited. The printed layer 6 may be formed, for example, on the surface of the first polypropylene resin layer 1 opposite to the first gas barrier adhesive layer 2, or between the first polypropylene resin layer 1 and the first gas barrier adhesive layer 2, or on the surface of the first polypropylene resin layer 1 on the side facing the first gas barrier adhesive layer 2. The printed layer 6 may also be formed on one side of the second polypropylene resin layer 4.

[0078] The printed layer 6 may be a layer formed by curing a composition containing a curing agent and ink. By using a composition containing a curing agent, delamination at the interface between the printed layer 6 and the first gas barrier adhesive layer 2 can be highly suppressed. More specifically, it is possible to suppress localized delamination of the first gas barrier adhesive layer 2 from the printed layer 6, which can cause blister-like appearance defects. An example of such a curing agent is LAMIAL Curing Agent B (manufactured by Sakata Inx Corporation).

[0079] The printed layer 6 may have a region composed of a cured product of a solvent-free adhesive. In this case, the printed layer 6 and adjacent layers may be bonded together by the cured product of the solvent-free adhesive. The solvent-free adhesive is an adhesive that does not contain organic solvents. The fact that the layer was formed using a solvent-free adhesive instead of a solvent-based adhesive can be analyzed, for example, by Fourier transform infrared spectroscopy. Examples of solvent-free adhesives include adhesives that contain a polyisocyanate component and a polyol component and do not contain organic solvents or water. The polyisocyanate component and the polyol component are prepared in appropriate amounts in advance and then mixed and used at the time of application.

[0080] To improve the adhesion of the printed layer 6, the surface of the layer forming the printed layer 6 (for example, the first polypropylene resin layer 1) may be subjected to various pretreatments such as corona treatment, plasma treatment, or flame treatment, and a coating layer such as an easy-adhesion layer or a medium layer may be provided.

[0081] (Medium layer) The medium layer 6a is a transparent or translucent layer that covers the surface of the printed layer 6 (the surface of the ink layer), protecting the ink layer contained in the printed layer 6 and smoothing the surface of the printed layer 6. By including the medium layer 6a in the gas barrier laminate, delamination at the interface between the printed layer 6 and the first gas barrier adhesive layer 2 can be suppressed to a high degree. More specifically, it is possible to suppress localized delamination of the first gas barrier adhesive layer 2 from the printed layer 6, which can cause blister-like appearance defects.

[0082] When the printing layer 6 includes an ink layer formed using printing ink, the medium layer 6a is a layer that covers the ink layer. The protection of the ink layer by the medium layer 6a improves the stability of the ink layer formed using printing ink. In addition, the improved smoothness of the printing layer 6 improves the adhesion between the printing layer 6 and other layers. When the printing layer 6 is located between the first polypropylene resin layer 1 and the first gas barrier adhesive layer 2, the printing layer 6 may have the medium layer 6a on the surface facing the first gas barrier adhesive layer 2. In this case, the first gas barrier adhesive layer 2 may be provided in direct contact with the medium layer 6a.

[0083] The medium layer 6a can be formed using a medium composition. That is, the medium layer 6a is a cured product of the medium composition. Unlike printing inks, the medium composition does not contain pigments or dyes. That is, the medium layer 6a contains a binder resin. Examples of binder resins include urethane resins, vinyl chloride-vinyl acetate copolymer resins, and mixtures thereof. As the medium composition, commercially available transparent or translucent inks can be used, for example, Bellcolor R Medium DT-8 (manufactured by Sakata Inx Corporation) or SMART-NT MEDIUM (manufactured by DIC Corporation) may be used.

[0084] [Adhesive Layer] The adhesive layer 7 is a cured product of the adhesive. Known adhesives can be used as the adhesive constituting the adhesive layer 7. Examples of adhesive materials that can be used include polyester-isocyanate resins, urethane resins, polyether resins, and epoxy resins. Among these, urethane resins or epoxy resins may be used. From an environmental perspective, adhesives with biomass-derived polymer components or those that are biodegradable may be used. Alternatively, the above-mentioned gas barrier adhesive may be used to form the adhesive layer 7.

[0085] The thickness of the adhesive layer 7 may be 0.1 to 20 μm, 0.1 to 10 μm, 0.1 to 5 μm, 0.5 to 20 μm, 0.5 to 10 μm, 0.5 to 5 μm, 1 to 20 μm, 1 to 10 μm, or 1 to 5 μm. When the thickness of the adhesive layer 7 is greater than or equal to the lower limit, the adhesive layer 7 tends to have sufficient adhesion to the second polypropylene resin layer 4 or sealant layer 5. On the other hand, when the thickness of the adhesive layer 7 is less than or equal to the upper limit, the flexibility of the gas barrier laminate 10 tends to be sufficiently maintained.

[0086] The adhesive layer 7 may be laminated so as to be in direct contact with the second polypropylene resin layer 4. Alternatively, the adhesive layer 7 may be laminated so as to be in direct contact with the sealant layer 5. In other words, the second polypropylene resin layer 4 and the sealant layer 5 may be laminated only via the adhesive layer 7.

[0087] [Second Gas Barrier Adhesive Layer] The second gas barrier adhesive layer 8 is a layer made of a cured product of a gas barrier adhesive. The second gas barrier adhesive layer 8 is a layer that has gas barrier properties. The oxygen permeability of the second gas barrier adhesive layer 8 can be within the same numerical range as that of the first gas barrier adhesive layer 2. In this case, the gas barrier properties of the gas barrier laminate 10 can be further improved. The second gas barrier adhesive constituting the second gas barrier adhesive layer 8 can be the same as the first gas barrier adhesive exemplified. The second gas barrier adhesive may be the same as the first gas barrier adhesive, or it may be different.

[0088] The thickness of the second gas barrier adhesive layer 8 may be 0.1 to 20 μm, 0.1 to 10 μm, 0.1 to 5 μm, 0.5 to 20 μm, 0.5 to 10 μm, 0.5 to 5 μm, 1 to 20 μm, 1 to 10 μm, or 1 to 5 μm. If the thickness of the second gas barrier adhesive layer 8 is greater than or equal to the lower limit, the gas barrier properties of the gas barrier laminate 10 can be further improved. On the other hand, if the thickness of the second gas barrier adhesive layer 8 is less than or equal to the upper limit, the flexibility of the gas barrier laminate 10 tends to be sufficiently maintained.

[0089] The second gas barrier adhesive layer 8 and the second polypropylene resin layer 4 may be laminated in direct contact (without any other layer interposed between the second gas barrier adhesive layer 8 and the second polypropylene resin layer 4). Alternatively, the second gas barrier adhesive layer 8 and the sealant layer 5 may be laminated in direct contact (without any other layer interposed between the second gas barrier adhesive layer 8 and the sealant layer 5). In other words, the second polypropylene resin layer 4 and the sealant layer 5 may be laminated only via the second gas barrier adhesive layer 8.

[0090] [Other] The gas barrier laminates 10, 20, and 30 may have any additional layers at any position besides those described above. Examples of such additional layers include a protective layer and an anchor coat layer. If the gas barrier laminates 10, 20, and 30 include a protective layer, the protective layer may be located outside the first polypropylene resin layer, or it may be provided on the outer surface of the first polypropylene resin layer 1. That is, the outer surface of the gas barrier laminates 10, 20, and 30 may be composed of a protective layer.

[0091] As described above, the films constituting the gas barrier laminates 10, 20, and 30 can all be polyolefin films, or they can all be polypropylene films. Such gas barrier laminates 10, 20, and 30 can be described as monomaterial packaging materials made from a single material with excellent recyclability. From this viewpoint, the total mass of components other than the polyolefin component (for example, adhesive and ink components) relative to the total mass of the gas barrier laminates 10, 20, and 30 can be 10% by mass or less, or 7.5% by mass or less. Also, the total mass of components other than the polypropylene component relative to the total mass of the gas barrier laminates 10, 20, and 30 may be 10% by mass or less, or 7.5% by mass or less.

[0092] The thickness of the gas barrier laminates 10, 20, and 30 can be appropriately determined according to their application. For example, the thickness of the gas barrier laminates 10, 20, and 30 can be 0.01 to 10 mm, 0.01 to 1.0 mm, 0.1 to 10 mm, or 0.1 to 1.0 mm.

[0093] The gas barrier laminates 10, 20, and 30 have an oxygen permeability of 1.0 cc / m³ under tropical conditions. ２ The oxygen permeability may be less than or equal to 1 / day·atm. Furthermore, the above oxygen permeability is 0.01 cc / m³. ２ ・day・atm or more, 0.1cc / m ２ ・day・atm or more or 0.2cc / m ２ - It may be 2 days atm or higher. The above oxygen permeability is 0.01 cc / m³. ２ ・day・atm or more 1.0cc / m ２ ・day・atm or less, 0.1cc / m ２・day・atm or more 1.0cc / m ２ ・day・atm or less or 0.2cc / m ２ ・day・atm or more 1.0cc / m ２ - The temperature may be less than or equal to day atm. In this specification, tropical conditions refer to conditions in which the atmosphere in contact with the outside of the gas barrier laminate 10 (the side with the first polypropylene resin layer 1) is 30°C and 70% RH (relative humidity), and the atmosphere in contact with the inside of the gas barrier laminate 10 (the side with the sealant layer 5) is 30°C and 90% RH.

[0094] The gas barrier laminates 10, 20, and 30 have an oxygen permeability of 0.8 cc / m³ at room temperature. ２ The oxygen permeability may be less than or equal to 1 / day·atm. Furthermore, the above oxygen permeability is 0.01 cc / m³. ２ ・day・atm or more, 0.1cc / m ２ ・day・atm or more or 0.2cc / m ２ - It may be 2 days atm or higher. The above oxygen permeability is 0.01 cc / m³. ２ ・day・atm or more 0.8cc / m ２ ・day・atm or less, 0.1cc / m ２ ・day・atm or more 0.8cc / m ２ ・day・atm or less or 0.2cc / m ２ ・day・atm or more 0.8cc / m ２ - The temperature may be less than or equal to day·atm. In this specification, room temperature conditions refer to conditions in which the atmosphere in contact with the outside of the gas barrier laminate 10 (the side with the first polypropylene resin layer 1) is 23°C and 50% RH, and the atmosphere in contact with the inside of the gas barrier laminate 10 (the side with the sealant layer 5) is 23°C and 90% RH.

[0095] The gas barrier laminates 10, 20, and 30 after retort treatment have an oxygen permeability of 1.2 cc / m³ under tropical conditions. ２ The oxygen permeability may be less than or equal to 1 / day·atm. Furthermore, the above oxygen permeability is 0.01 cc / m³. ２ ・day・atm or more, 0.1cc / m ２ ・day・atm or more or 0.3cc / m ２ - It may be 1 / day atm or higher. The above oxygen permeability is 1.5 cc / m³. ２・day・atm or less, or 1.8 cc / m ２ ・day・atm or less. The above oxygen permeability may be 0.01 to 1.2 cc / m ２ ・day・atm, 0.1 to 1.2 cc / m ２ ・day・atm, 0.3 to 1.2 cc / m ２ ・day・atm, 0.01 to 1.5 cc / m ２ ・day・atm, 0.1 to 1.5 cc / m ２ ・day・atm, 0.3 to 1.5 cc / m ２ ・day・atm, 0.01 to 1.8 cc / m ２ ・day・atm, 0.1 to 1.8 cc / m ２ ・day・atm, or 0.3 to 1.8 cc / m ２ ・day・atm. The conditions for the above retort treatment may be 0.2 MPa at 125°C for 15 minutes.

[0096] Further, the gas barrier laminates 10, 20, 30 after retort treatment have an oxygen permeability of 1.0 cc / m under room temperature conditions ２ ・day・atm or less. Further, the above oxygen permeability is 0.01 cc / m ２ ・day・atm or more, 0.1 cc / m ２ ・day・atm or more, or 0.3 cc / m ２ ・day・atm or more. The above oxygen permeability is 1.2 cc / m ２ ・day・atm or less, or 1.5 cc / m ２ ・day・atm or less. The above oxygen permeability may be 0.01 to 1.0 cc / m ２ ・day・atm, 0.1 to 1.0 cc / m ２ ・day・atm, 0.3 to 1.0 cc / m ２ ・day・atm, 0.01 to 1.2 cc / m ２ ・day・atm, 0.1 to 1.2 cc / m ２ ・day・atm, 0.3 to 1.2 cc / m ２ ・day・atm, 0.01 to 1.5 cc / m ２ ・day・atm, 0.1 to 1.5 cc / m ２ ・day・atm, or 0.3 to 1.5 cc / m ２- Day atm may also be used. The above retort processing conditions may also be 0.2 MPa, 125°C for 15 minutes.

[0097] The gas barrier laminates 10, 20, and 30 can be suitably used in a variety of applications, including packaging products such as containers and bags, sheet molded products such as decorative sheets and trays, optical films, resin plates, various label materials, lid materials, and laminate tubes, and are particularly suitable for use in packaging products. Examples of packaging products include pillow bags, standing pouches, three-sided sealed bags, and four-sided sealed bags.

[0098] [Packaging] Figure 4 is a schematic cross-sectional view showing one embodiment of the packaging. The packaging 200 shown in this figure comprises a packaging bag 100 and contents C contained in the packaging bag 100. The packaging bag 100 is made by manufacturing a bag from any of the gas barrier laminates 10, 20, or 30, or a modified version thereof. The packaging bag 100 may be formed by folding one gas barrier laminate in half so that the sealant layers 5 face each other, and then heat-sealing three sides, or by stacking two gas barrier laminates so that the sealant layers 5 face each other, and then heat-sealing the outer edges. The packaging bag 100 may also be provided with a gusset and a bottom.

[0099] The contents C contained in the packaging 200 are not particularly limited, but may be, for example, food, pharmaceuticals, etc. The contents C may be a liquid, solid, or gel. The contents C may contain an acidic or alkaline solution. The pH of the solution may be 2 to 6 or 8 to 12. When the contents C contains water, such as a liquid or gel, the oxygen barrier properties of the packaging bag 100 do not decrease even under tropical conditions, thus suppressing the deterioration of the contents C. The above effect can be suitably achieved even when the contents C contains an acidic solution.

[0100] The packaging 200 can be subjected to heat sterilization treatments such as retort processing or boiling. Retort processing is a method of pressurized sterilization of microorganisms such as mold, yeast, and bacteria in order to preserve food, pharmaceuticals, etc. Typically, the packaging bag containing the food is subjected to pressurized sterilization treatment at 105 to 140°C and 0.15 to 0.30 MPa for 10 to 120 minutes. Retort equipment comes in two types: steam type, which uses heated steam, and hot water type, which uses pressurized heated water. The appropriate type should be used depending on the sterilization requirements for the food contents.

[0101] This disclosure relates to the following: [1] A gas barrier laminate comprising a first polypropylene resin layer, a first gas barrier adhesive layer, an inorganic vapor deposition layer, a second polypropylene resin layer, and a sealant layer, in this order from the outside to the inside. [2] The gas barrier laminate according to [1], further comprising a printed layer between the first polypropylene resin layer and the first gas barrier adhesive layer, wherein the printed layer contains a curing agent. [3] The gas barrier laminate according to [1] or [2], further comprising a printed layer between the first polypropylene resin layer and the first gas barrier adhesive layer, wherein the printed layer has a medium layer on the surface facing the first gas barrier adhesive layer. [4] The mass per unit area of ​​the first gas barrier adhesive layer is 1.65 g / m². ２ The gas barrier laminate described in any one of [1] to [3] above. [5] Oxygen permeability under tropical conditions is 1.0 cc / m ２ - The gas barrier laminate according to any one of [1] to [4], wherein the temperature is less than or equal to day·atm, and the tropical conditions are such that the atmosphere in contact with the outside of the gas barrier laminate is at a temperature of 30°C and a relative humidity of 70%, and the atmosphere in contact with the inside of the gas barrier laminate is at a temperature of 30°C and a relative humidity of 90%. [6] Oxygen permeability at room temperature is 0.8 cc / m ２A gas barrier laminate according to any one of [1] to [5], wherein the temperature is less than or equal to day·atm, and the room temperature conditions are such that the atmosphere in contact with the outside of the gas barrier laminate is at a temperature of 23°C and a relative humidity of 50%, and the atmosphere in contact with the inside of the gas barrier laminate is at a temperature of 23°C and a relative humidity of 90%. [7] A gas barrier laminate according to any one of [1] to [6], wherein the first gas barrier adhesive layer is composed of a cured epoxy adhesive. [8] A gas barrier laminate according to any one of [1] to [7], wherein the inorganic vapor deposition layer is directly provided on the surface of the second polypropylene resin layer. [9] A gas barrier laminate according to [8], wherein the second polypropylene resin layer has an anchor coat on the surface on which the inorganic vapor deposition layer is provided.

[10] A gas barrier laminate according to any one of [1] to [9], further comprising an adhesive layer between the second polypropylene resin layer and the sealant layer, wherein the adhesive layer is composed of an epoxy resin or a urethane resin.

[11] A gas barrier laminate according to any one of [1] to

[10] , further comprising a second gas barrier adhesive layer between the second polypropylene resin layer and the sealant layer.

[12] A gas barrier laminate according to any one of [1] to

[11] , wherein the second polypropylene resin layer has a surface layer on the surface facing the inorganic vapor deposition layer, and the surface layer contains a resin having a melting point of 150°C or higher.

[13] A gas barrier laminate according to any one of [1] to

[12] , wherein the inorganic vapor deposition layer contains silicon oxide, and the O / Si ratio of the inorganic vapor deposition layer is 1.7 or more and 2.0 or less.

[14] A gas barrier laminate according to any one of [1] to

[13] , further comprising a printing layer between the first polypropylene resin layer and the first gas barrier adhesive layer, and further comprising an adhesive layer between the second polypropylene resin layer and the sealant layer.

[15] A packaging bag made by forming a bag from the gas barrier laminate according to any one of [1] to

[14] . A packaging body comprising the packaging bag described in

[16] and

[15] , and the contents contained in the packaging bag.

[0102] <Example 1> (Preparation of anchor coating agent) Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups of tolylene diisocyanate was equal to the number of OH groups of acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solids content (total amount of acrylic polyol and tolylene diisocyanate) was 5% by mass. To the diluted mixture, β-(3,4-epoxycyclohexyl)trimethoxysilane was added in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coating forming composition (anchor coating agent).

[0103] (Preparation of Gas Barrier Film) A gas barrier film with the following layer configuration was prepared using the following procedure. Layer configuration: second polypropylene resin layer / anchor coat / inorganic vapor deposition layer First, the above anchor coat forming composition was applied to the corona-treated surface of a biaxially oriented polypropylene film (OPP-2) that had been corona-treated on one side, using the gravure roll coating method, and dried and cured at 60°C, with a coating amount of 0.1 g / m². ２ An anchor coat (AC) made of an acrylic polyurethane resin was formed. Next, a transparent inorganic vapor deposition layer (G1) made of silicon dioxide with a thickness of 30 nm was formed using a vacuum deposition apparatus with electron beam heating. ME-1 (model number, manufactured by Mitsui Chemicals Tohcello Co., Ltd., thickness 20 μm) was used as the biaxially oriented polypropylene film. For the inorganic vapor deposition layer (G1), the vapor deposition material species was adjusted to form a silica vapor deposition layer with an O / Si ratio of 1.8. The O / Si ratio was measured using an X-ray photoelectron spectroscopy analyzer (manufactured by JEOL Ltd., product name: JPS-90MXV), with a non-monochromatic MgKα (1253.6 eV) X-ray source and an X-ray output of 100 W (10 kV-10 mA). For quantitative analysis to determine the O / Si ratio, relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p were used. This resulted in obtaining a gas barrier film to serve as an intermediate layer.

[0104] (Formation of Printed Film) A printed film with the following layer configuration was prepared by the following procedure: Layer configuration: First polypropylene resin layer / Printed layer Printed ink composition A was prepared by mixing and dispersing Belle Color R GERANIUM 365 (model number, manufactured by Sakata Inx Corporation) and a curing agent (manufactured by Sakata Inx Corporation, model number: LAMIAL curing agent B) in a solvent (product name: SOLVENT BELLE COLOR K-3). The solid content of printed ink composition A was 9%, and the amount of curing agent was 3% by mass in terms of solid content weight. Furthermore, printing ink compositions B and C were prepared in the same manner as printing ink composition A, except that Belle Color R BLUE 800 (model number, manufactured by Sakata Inx Corporation) and Belle Color R WHITE 1015 D (model number, manufactured by Sakata Inx Corporation) were used instead of Belle Color R GERANIUM 365. Next, a pattern was printed on the corona-treated side of a biaxially oriented polypropylene film (OPP-1) that had been corona-treated on one side, using a printing press and applying the above printing ink compositions A to C in that order to form a printed layer (PR), thereby obtaining a printed film having a laminated structure of OPP-1 (first polypropylene resin layer) / PR (printed layer). FOR (model number, manufactured by Futamura Chemical Co., Ltd., thickness 20 μm) was used as the above biaxially oriented polypropylene film.

[0105] (Preparation of gas barrier adhesive) 47.4 parts by mass of ion-exchanged water and 15.0 parts by mass of isopropyl alcohol were mixed, and 33.5 parts by mass of Takelac WPB-341M (manufactured by Mitsui Chemicals, Inc.) was added to the mixture. Furthermore, 4.1 parts by mass of Carbodilite SV-02 (manufactured by Nisshinbo Chemical Co., Ltd.) was added to the mixture to prepare a gas barrier adhesive with a solid content of 10% by weight.

[0106] (Fabrication of Gas Barrier Laminate) The printed film was laminated onto the G1 (inorganic vapor deposition layer) of the gas barrier film by dry lamination using the gas barrier adhesive, with the PR (printed layer) facing the G1 (inorganic vapor deposition layer). Subsequently, a sealant layer, CPP-1 (unoriented polypropylene film, MD direction heat shrinkage rate: 1.90%, TD direction heat shrinkage rate: 2.05%, thickness: 60 μm), was laminated onto the OPP-2 of the gas barrier film by dry lamination using a two-component adhesive (manufactured by Mitsui Chemicals, Inc., product name: main component A525 / curing agent A52). At this time, the MD direction of OPP-1, the MD direction of OPP-2, and the MD direction of CPP-1 were aligned. This resulted in the production of a gas barrier laminate having a laminated structure of OPP-1 (first polypropylene resin layer) / PR (printing layer) / GS (gas barrier adhesive layer) / G1 (inorganic vapor deposition layer) / AC (anchor coat) / OPP-2 (second polypropylene resin layer) / S (adhesive layer) / CPP-1 (sealant layer). The thickness of both the gas barrier adhesive layer (GS) and the adhesive layer (S) in the obtained gas barrier laminate was 2.1 μm. The mass per unit area of ​​the gas barrier adhesive layer was 1.7 g / m². ２ That was the case.

[0107] <Comparative Example 1> In the preparation of the gas barrier laminate, the printed film was laminated by dry lamination using a two-component adhesive (manufactured by Mitsui Chemicals, Inc., product name: main component A525 / curing agent A52) so that the PR (printed layer) was on the OPP-2 (second polypropylene resin layer) side, and the sealant layer CPP-1 was laminated on the OPP-2 of the gas barrier film by dry lamination using the above gas barrier adhesive. The gas barrier laminate had a laminated structure of OPP-1 (first polypropylene resin layer) / PR (printed layer) / / S (adhesive layer) / / OPP-2 (second polypropylene resin layer) / AC (anchor coat) / G1 (inorganic vapor deposition layer) / / GS (gas barrier adhesive layer) / CPP-1 (sealant layer). The thickness of both the gas barrier adhesive layer (GS) and the adhesive layer (S) in the obtained gas barrier laminate was 2.1 μm.

[0108] (Oxygen Barrier Properties) The oxygen permeability (OTR) of the gas barrier laminate was measured using an oxygen permeability measuring device (MOCON Corporation, product name: OX-TRAN2 / 20). The measurement was carried out in accordance with JIS K-7126, Method B, except that the gas barrier laminate was installed so that the sealant layer of the laminate faced the carrier gas introduction side of the chamber, and the carrier gas and test gas were set to the following conditions. The results are shown in Table 1. In the following table, OTR refers to "oxygen permeability (cc / m³)". ２ It shows "day atm". <Room temperature conditions> Test gas: Air at 23°C and 50% RH Carrier gas: Air at 23°C and 90% RH <Tropical conditions> Test gas: Air at 30°C and 70% RH Carrier gas: Air at 30°C and 90% RH

[0109] (Retorting) The gas barrier laminates of Example 1 and Comparative Example 1 were cut to a size of 15 cm x 20 cm. The cut gas barrier laminates were folded in the longitudinal direction at the center so that the sealant layers faced each other, and two sides were impulse sealed to form a pouch. 200 ml of tap water was placed inside the pouch as the contents, and the remaining side was impulse sealed to create a three-sided sealed pouch (packaging bag). The resulting pouch was retorted in a retort apparatus at 0.2 MPa and 125°C for 15 minutes. After retorting, the pouch was opened, the tap water inside was discarded, and it was thoroughly dried.

[0110] (Appearance after retort processing) The appearance of the gas barrier laminate after the above retort processing was observed, and the occurrence of film delamination or lifting was visually evaluated. The evaluation criteria were as follows. The results are shown in Table 1. <Evaluation Criteria> A: No delamination or lifting occurred B: Delamination or lifting occurred in 1 to 10 locations C: Delamination or lifting occurred in 10 or more locations

[0111] (Oxygen barrier properties after retort treatment) The oxygen barrier properties of the gas barrier laminate after the above retort treatment were evaluated. The results are shown in Table 1.

[0112] (Long-term storage stability) The gas barrier laminates of Example 1 and Comparative Example 1 were cut to a size of 15 cm x 20 cm. The cut gas barrier laminates were folded in the longitudinal direction at the center so that the sealant layers faced each other, and two sides were impulse-sealed to form a pouch. 200 ml of tap water was placed inside the pouch as the contents, and the remaining side was impulse-sealed to create a three-sided sealed pouch (packaging bag). The resulting pouch was stored in a 30°C, 70% RH environment. After that, the pouch was opened, the tap water inside was discarded, and it was thoroughly dried. Then, the oxygen barrier performance after long-term storage was measured in the same manner as the oxygen barrier performance evaluation under tropical conditions after retort treatment described above. In addition, long-term storage tests and oxygen barrier performance evaluations were performed in the same manner as described above, except that a sauce (pH: 4) made by mixing vinegar, oil, and ketchup in a 1:1:1 mass ratio was used instead of tap water as the contents. The results are shown in Table 1.

[0113]

[0114] <Example 2> A gas barrier laminate according to Example 2 was fabricated in the same manner as in Example 1, except that a printed layer was not formed.

[0115] <Example 3> The gas barrier laminate of Example 3 was manufactured in the same manner as in Example 2, except that CPP-2 (unoriented polypropylene film, MD-direction thermal shrinkage rate: 0.86%, thickness: 60 μm) was used instead of CPP-1 as the sealant layer.

[0116] <Comparative Example 2> First, an anchor coat forming composition was prepared in the same manner as in Example 1. Next, a gas barrier coating layer forming composition was prepared as follows. (Preparation of Gas Barrier Coating Layer Forming Composition) A gas barrier coating layer forming composition was prepared by mixing the following liquids A, B, and C in a mass ratio of 65 / 25 / 10, respectively. Liquid A: Tetraethoxysilane (Si(OC) ２ H ５ ) ４ ) 17.9 g and 10 g methanol are mixed with 72.1 g of 0.1 N hydrochloric acid and stirred for 30 minutes to hydrolyze the solids, resulting in a solid content of 5% by mass (SiO ２ Hydrolyzed solutions (converted). Solution B: 5% by mass water / methanol solution of polyvinyl alcohol (water:methanol mass ratio is 95:5). Solution C: Hydrolyzed solution of 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate diluted to 5% by mass solids with a water / isopropyl alcohol mixture (water:isopropyl alcohol mass ratio is 1:1).

[0117] Next, an anchor coat (AC) and an inorganic vapor-deposited layer (G1) were formed on OPP-2 in the same manner as in Example 1. Then, the gas barrier coating layer forming composition was applied to the inorganic vapor-deposited layer (G1) by gravure roll coating, and heated and dried in an oven under conditions of tension 20 N / m and drying temperature 120°C to form a gas barrier coating layer (GC) with a thickness of 0.5 μm. This yielded a gas barrier film that would serve as an intermediate layer.

[0118] Then, a gas barrier laminate was fabricated as follows: (Fabrication of Gas Barrier Laminate) On the GC (gas barrier coating layer) of the gas barrier film, OPP-1, which will be the base layer, was laminated by dry lamination using a two-component adhesive (manufactured by Mitsui Chemicals, Inc., product name: main component A525 / curing agent A52). Subsequently, CPP-1, which will be the sealant layer, was laminated on the OPP-2 of the gas barrier film using dry lamination using the same adhesive. At this time, the MD direction of OPP-1, the MD direction of OPP-2, and the MD direction of CPP-1 were aligned. As a result, a gas barrier laminate having a laminated structure of OPP-1 (base layer) / S (adhesive layer) / GC (gas barrier coating layer) / G1 (inorganic vapor deposition layer) / AC (anchor coat) / OPP-2 / S (adhesive layer) / CPP-1 (sealant layer) was manufactured. The thickness of the adhesive layer (S) in the obtained gas barrier laminates was 2.1 μm in all cases.

[0119] <Comparative Example 3> The gas barrier laminate of Comparative Example 3 was manufactured in the same manner as in Comparative Example 2, except that CPP-2 was used instead of CPP-1 as the sealant layer.

[0120] The gas barrier laminates of Examples 2 and 3 and Comparative Examples 2 and 3 were subjected to retort treatment in the same manner as in Example 1, and the oxygen permeability (OTR) under tropical conditions after retort treatment was measured. The results are shown in Table 2.

[0121]

[0122] <Examples 4-6> Gas barrier laminates of Examples 4-6 were prepared in the same manner as in Example 1, except that the amount of gas barrier adhesive applied was the amount shown in Table 3, no curing agent was mixed into each of the printing ink compositions A-C, and an adhesive layer (S) was formed using a gas barrier adhesive instead of a two-component adhesive.

[0123] <Example 7> Gas barrier laminates were prepared in the same manner as in Example 4, except that LAMIAL HARDNER B (manufactured by Sakata Inx Corporation) was mixed as a curing agent at a rate of 3% by weight of ink solids to each of the printing ink compositions A to C.

[0124] <Example 8> A gas barrier laminate was prepared in the same manner as in Example 4, except that the printed film was formed as follows. (Formation of printed film) First, printing ink compositions A to C were prepared in the same manner as in Example 1. Next, a medium layer forming composition (medium composition) was prepared by mixing and dispersing Bellcolor R Medium DT-8 (model number, manufactured by Sakata Inx Corporation) in a solvent (product name: SOLVENT BELLE COLOR K-3, manufactured by Sakata Inx Corporation) so that the solid content was 12%. Next, a pattern was printed on the corona-treated surface of OPP-1, which had been corona-treated on one side, using a printing press with the above printing ink compositions A to C in that order. After that, a medium layer was printed on the pattern using the above medium layer forming composition with a printing press. In this way, a printed film having a laminated structure of OPP-1 (first polypropylene resin layer) / PR (printed layer) was obtained.

[0125] The gas barrier laminates of Examples 4 to 8 were subjected to retort treatment in the same manner as in Example 1, and the appearance after retort treatment and the oxygen permeability (OTR) under tropical conditions were measured. The results are shown in Table 3.

[0126] (Laminate strength after retort processing) The laminate strength of the gas barrier laminates of Examples 4 to 8 of the above retort processing was evaluated. Measurements were performed in accordance with JIS K6854, with a test width of 15 mm, a peeling speed of 300 mm / min, and a peeling angle of T. Measured values ​​are expressed in units of [N / 15 mm]. Measurement samples were prepared by cutting pouches into strips. In this case, the heat-sealed portion of the pouch was used as the heat-sealed portion of the measurement sample. The results are shown in Table 3.

[0127]

[0128] 1...First polypropylene resin layer, 2...First gas barrier adhesive layer, 3...Inorganic vapor deposition layer, 4...Second polypropylene resin layer, 4a...Anchor coat, 5...Sealant layer, 6...Printing layer, 6a...Medium layer, 7...Adhesive layer, 8...Second gas barrier adhesive layer, 10, 20, 30...Gas barrier laminate, 100...Packaging bag, C...Contents, 200...Packaging body.

Claims

A first polypropylene resin layer and A first gas barrier adhesive layer, Inorganic vapor-deposited layer, A second polypropylene resin layer, The sealant layer, A gas barrier laminate, arranged in this order from the outside to the inside. 　 A printing layer is further provided between the first polypropylene resin layer and the first gas barrier adhesive layer. The gas barrier laminate according to claim 1, wherein the printed layer contains a curing agent. 　 A printing layer is further provided between the first polypropylene resin layer and the first gas barrier adhesive layer. The gas barrier laminate according to claim 1 or 2, wherein the printed layer has a medium layer on the surface facing the first gas barrier adhesive layer. 　 The mass per unit area of ​​the first gas barrier adhesive layer is 1.65 g / m². ２ The gas barrier laminate according to any one of claims 1 to 3. 　 The gas barrier laminate according to any one of claims 1 to 4, wherein the first gas barrier adhesive layer is composed of a cured epoxy adhesive. 　 The gas barrier laminate according to any one of claims 1 to 5, wherein the inorganic vapor deposition layer is directly provided on the surface of the second polypropylene resin layer. 　 The gas barrier laminate according to claim 6, wherein the second polypropylene resin layer has an anchor coat on the surface on which the inorganic vapor deposition layer is provided. 　 The second polypropylene resin layer and the sealant layer are further provided with an adhesive layer. The gas barrier laminate according to any one of claims 1 to 7, wherein the adhesive layer is composed of an epoxy resin or a urethane resin. 　 The gas barrier laminate according to any one of claims 1 to 8, further comprising a second gas barrier adhesive layer between the second polypropylene resin layer and the sealant layer. 　 The second polypropylene resin layer has a surface layer on the surface facing the inorganic vapor deposition layer, The gas barrier laminate according to any one of claims 1 to 9, wherein the surface layer contains a resin with a melting point of 150°C or higher. 　 The inorganic vapor deposition layer contains silicon dioxide, The gas barrier laminate according to any one of claims 1 to 10, wherein the O / Si ratio of the inorganic vapor deposition layer is 1.7 or more and 2.0 or less. 　 A printing layer is further provided between the first polypropylene resin layer and the first gas barrier adhesive layer. The gas barrier laminate according to any one of claims 1 to 11, further comprising an adhesive layer between the second polypropylene resin layer and the sealant layer. 　 A packaging bag made by forming a bag from a gas barrier laminate according to any one of claims 1 to 12. 　 The packaging bag according to claim 13, The contents contained in the aforementioned packaging bag, A packaging body equipped with the following features. 　 The packaging according to claim 14, wherein the contents are acidic.

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