Packaging bags

Abstract

To provide a laminate with excellent interlayer adhesion to a vapor-deposited film and a high gas barrier property.SOLUTION: In a first aspect, a packaging bag according to the present invention comprises a laminate having at least a base material, a vapor-deposited film and a sealant layer, where the base material comprises at least a polyethylene resin layer and a surface resin layer and the sealant layer is composed of a polyethylene resin, a surface resin layer of the base material contains a resin material with a melting point of 150°C or higher, the vapor-deposited film is provided on the surface resin layer of the base material, and the base material has been subjected to drawing processing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a packaging bag.

[0002] BACKGROUND ART Conventionally, resin films made of polyester resins such as polyethylene terephthalate (hereinafter also referred to as polyester films) have been used to produce packaging bags because they have excellent mechanical properties, chemical stability, heat resistance, and transparency, as well as being inexpensive.

[0003] Such polyester films are used as a substrate or intermediate layer, and are usually laminated with a polyethylene film as a sealant layer to form a laminate, which is then formed into a packaging bag.

[0004] The packaging bags obtained by forming a laminate of the above-mentioned different resin films, i.e., polyester film and polyethylene film, are difficult to separate into their individual layers, and packaging bags collected after use are not suitable for recycling, and are not actively recycled at present.

[0005] In light of this current situation, and with the aim of improving the recyclability of packaging bags, studies are being conducted on the production of packaging bags using laminates made of the same material (mono-material packaging bags) by using stretched polyethylene film (stretched polyethylene film) as the base material instead of polyester film. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2005-053223 Summary of the Invention [Problem to be solved by the invention]

[0007] Recently, the present inventors attempted to form a vapor-deposited film on the surface of the stretched polyethylene film in order to compensate for the reduced gas barrier properties that result from replacing the polyester film with a stretched polyethylene film. However, they discovered a new problem: the adhesion between the stretched polyethylene film and the vapor-deposited film was insufficient, making it impossible to obtain satisfactory gas barrier properties.

[0008] Surprisingly, the inventors discovered that by providing a surface resin layer containing a resin material with a melting point of 150°C or higher on the surface of a stretched polyethylene film, the adhesion of the vapor-deposited film formed on the surface resin layer is improved, and as a result, the gas barrier properties are significantly improved, thereby solving the above-mentioned problems.

[0009] The present invention was made based on this finding, and the problem it aims to solve is to provide a mono-material packaging container (packaging bag) that has high recyclability and high gas barrier properties. [Means for solving the problem]

[0010] In a first aspect, the packaging bag of the present invention is a packaging bag made of a laminate including at least a substrate, a vapor-deposited film, and a sealant layer, the substrate comprises at least a polyethylene resin layer and a surface resin layer, the sealant layer is made of a polyethylene resin, the surface resin layer of the substrate contains a resin material with a melting point of 150°C or higher, the vapor-deposited film is provided on a surface resin layer of the substrate, The substrate is characterized in that it has been subjected to a stretching treatment.

[0011] In a second aspect, the packaging bag of the present invention is a packaging bag made of a laminate including at least a substrate, an intermediate layer, and a sealant layer, the intermediate layer comprises a polyethylene resin layer, a surface resin layer, and a vapor-deposited film provided on the surface resin layer, the substrate and the sealant layer are both made of polyethylene resin, the surface resin layer of the intermediate layer contains a resin material with a melting point of 150°C or higher, The polyethylene resin layer of the intermediate layer and the surface resin layer are characterized in that they have been subjected to a stretching treatment.

[0012] In a third aspect, the packaging bag of the present invention is a packaging bag made of a laminate including at least a substrate, a vapor-deposited film, and a sealant layer, the sealant layer comprises a surface resin layer and a polyethylene resin layer, The substrate is made of polyethylene resin, the surface resin layer of the sealant layer contains a resin material with a melting point of 150°C or higher, The vapor-deposited film is provided on a surface resin layer of the sealant layer.

[0013] In one embodiment, the surface resin layer contains a resin material having a melting point of 150°C or higher and 265°C or lower.

[0014] In one embodiment, the difference in melting point between the polyethylene resin and the resin material contained in the surface resin layer and having a melting point of 150°C or higher is 20 to 80°C.

[0015] In one embodiment, the resin material of the surface resin layer is made of a polymer having a polar group.

[0016] In one embodiment, the resin material of the surface resin layer is one or more resin materials selected from ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyester, nylon 6, nylon 6,6, nylon 6-nylon 6,6 copolymer, MXD nylon, and amorphous nylon.

[0017] In one embodiment, the polyethylene resin layer has a multi-layer structure.

[0018] In one embodiment, the polyethylene resin layer comprises at least one layer containing a compatibilizer.

[0019] In one embodiment, the surface resin layer is provided so as to be in contact with the layer containing a compatibilizer of the polyethylene resin layer.

[0020] In one embodiment, the laminate further comprises a barrier coat layer provided on the vapor-deposited film.

[0021] In one embodiment, the content of polyethylene resin in the entire laminate is 80% by mass or more. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a mono-material packaging container (packaging bag) having high recyclability and high gas barrier properties. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a front view showing an embodiment of a packaging bag of the present invention. [Figure 2] 1 is a perspective view showing one embodiment of a packaging bag of the present invention. [Figure 3] 1 is a schematic cross-sectional view showing one embodiment of a laminate according to a first aspect provided in a packaging bag of the present invention. [Figure 4] 1 is a schematic cross-sectional view showing one embodiment of a laminate according to a first aspect provided in a packaging bag of the present invention. [Figure 5] FIG. 1 is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus. [Figure 6] FIG. 1 is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus. [Figure 7] FIG. 3 is a schematic cross-sectional view showing one embodiment of a laminate according to a second aspect, which is included in the packaging bag of the present invention. [Figure 8] FIG. 3 is a schematic cross-sectional view showing one embodiment of a laminate according to a second aspect, which is included in the packaging bag of the present invention. [Figure 9] FIG. 3 is a schematic cross-sectional view showing one embodiment of a laminate according to a second aspect, which is included in the packaging bag of the present invention. [Figure 10] FIG. 3 is a schematic cross-sectional view showing one embodiment of a laminate according to a third aspect, which is included in the packaging bag of the present invention. [Figure 11] FIG. 3 is a schematic cross-sectional view showing one embodiment of a laminate according to a third aspect, which is included in the packaging bag of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] (packaging bag) The shape of the packaging bag is not particularly limited, and it is preferable to change it appropriately depending on the contents to be filled. For example, various shapes of packaging bags can be mentioned, such as a standing pouch type, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a palm seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type. The contents to be filled are not particularly limited, and may be liquid, powder, or gel. The contents may be food or non-food.

[0025] In one embodiment, the packaging bag 10 of the present invention is a packaging bag formed by bonding two laminates together, as shown in FIG. 1 (the shaded areas are the heat-sealed areas).

[0026] A packaging bag having the configuration shown in FIG. 1 can be produced by preparing two laminates described below, stacking these laminates with their sealant layers facing each other, and heat-sealing three sides.

[0027] In one embodiment, the packaging container of the present invention is a standing pouch-type packaging bag 20 (hereinafter simply referred to as a standing pouch 20) as shown in FIG. 2, and the standing pouch 20 has a body portion (side sheet) and a bottom portion (bottom sheet). The body (side sheets) of the standing pouch 20 is made of the laminate described below. The bottom (bottom sheet) may also be made of the laminate described below. By adopting such a configuration, the gas barrier properties of the standing pouch 20 can be further improved. Furthermore, the recyclability of the pouch can also be improved.

[0028] The body (side sheet) of a standing pouch 20 as shown in FIG. 2 can be formed by bag making so that the sealant layer of the laminate becomes the innermost layer. In another embodiment, two laminates are prepared, overlapped with the sealant layers facing each other, and two V-folded laminates are inserted into both ends of the overlapped laminate with the sealant layers facing outward, followed by heat sealing to form the body (side sheets) of the standing pouch 20. This production method makes it possible to produce a stand-up pouch having a body with side gussets. The bottom (bottom sheet) of the standing pouch 20 can be formed by inserting a laminate between pre-formed body portions (side sheets) and heat-sealing the laminate. More specifically, the laminate can be folded into a V shape with the sealant layer facing outward, inserted between pre-formed side sheets, and heat-sealed.

[0029] Furthermore, the packaging bag 10 may be provided with easy-opening means 31 as shown in FIG. Examples of the easy-to-open means 31 include, as shown in FIG. 1, a notch 32 that serves as the starting point for tearing, and a half-cut line 33 formed by laser processing or a cutter as the path for tearing.

[0030] The packaging container may also be a stand-up pouch 20 equipped with a dispensing nozzle part 41, as shown in FIG. From the viewpoint of ease of opening, the stand pouch 20 may have a curved portion 42 that curves inward, as shown in FIG. Furthermore, it may have a cutout 43 formed by a laser beam or the like.

[0031] The laminate constituting the packaging bag of the present invention will be described below.

[0032] (Laminate according to the first aspect) 3, a laminate 50 includes a substrate 51, a vapor-deposited film 52, and a sealant layer 53, and the substrate 51 includes a polyethylene resin layer 54 and a surface resin layer 55. The vapor-deposited film 52 is provided adjacent to the surface resin layer 55 of the substrate 51. The polyethylene resin layer of the base material of the laminate and the sealant layer contain the same resin, i.e., polyethylene resin, and a laminate having such a configuration can be suitably used as a laminate for producing mono-material packaging containers.

[0033] The content of polyethylene resin relative to the total amount of solids contained in the laminate constituting the packaging bag is preferably 80% by mass or more, more preferably 90% by mass or more, which makes it possible to obtain a laminate that can be suitably used for producing mono-material packaging containers (packaging bags).

[0034] In one embodiment, the substrate 51 may further include an adhesive resin layer 56 between the polyethylene resin layer 54 and the surface resin layer 55, as shown in FIG.

[0035] Furthermore, in one embodiment, the laminate 50 includes a barrier coat layer (not shown) between the vapor-deposited film 52 and the sealant layer 53 .

[0036] Additionally, in one embodiment, laminate 50 includes adhesive layers between any of the layers (not shown).

[0037] Hereinafter, each layer included in the laminate according to the first aspect will be described.

[0038] (base material) The substrate includes at least a polyethylene resin layer and a surface resin layer. In one embodiment, the substrate includes an adhesive resin layer between the polyethylene resin layer and the surface resin layer.

[0039] The ratio of the thickness of the surface resin layer to the total thickness of the base material is preferably 2% or more and 20% or less, and more preferably 4% or more and 15% or less. By making the ratio of the thickness of the surface resin layer to the total thickness of the substrate 2% or more, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties can be further improved. Furthermore, by setting the ratio of the thickness of the surface resin layer to the total thickness of the substrate to 20% or less, a laminate that can be suitably used for producing mono-material packaging containers can be obtained, and the film-forming properties and processability of the substrate can be further improved.

[0040] (Polyethylene resin layer) The polyethylene resin layer is made of a polyethylene resin. As the polyethylene resin, high density polyethylene resin (HDPE), medium density polyethylene resin (MDPE), low density polyethylene resin (LDPE), linear low density polyethylene resin (LLDPE), and very low density polyethylene resin (VLDPE) can be used. Furthermore, a copolymer of ethylene and other monomers can also be used as the polyethylene resin. Furthermore, as the polyethylene resin, a biomass-derived polyethylene resin or a mechanically recycled or chemically recycled polyethylene resin can also be used.

[0041] Here, the high density polyethylene resin has a density of 0.945 g / cm 3 The above polyethylene resins can be used, and the medium density polyethylene resins are those with a density of 0.925 g / cm 3 More than 0.945g / cm 3 A polyethylene resin having a density of less than 0.900 g / cm can be used.3 More than 0.925g / cm 3 A polyethylene resin having a density of less than 0.900 g / cm can be used. 3 More than 0.925g / cm 3 Polyethylene resins with a density of less than 0.900 g / cm can be used, and ultra-low density polyethylene resins have a density of less than 0.900 g / cm. 3 Polyethylene resins less than 1000 MPa can be used.

[0042] The polyethylene resin content in the polyethylene resin layer is preferably 70% by mass or more, and more preferably 80% by mass or more, which allows the laminate to be more suitably used in the production of mono-material packaging containers.

[0043] In one embodiment, the polyethylene resin layer may include at least one layer containing a compatibilizer. By including a compatibilizer in the polyethylene resin layer, when a packaging container made using the laminate is heated and melted for recycling, the resin material having a melting point of 150°C or higher contained in the surface resin layer and the polyethylene resin contained in the polyethylene resin layer are uniformly mixed together, which effectively prevents a decrease in the physical properties and a decrease in the transparency. In addition, when the polyethylene resin layer has a multilayer structure, the compatibilizer is preferably contained in a layer in contact with the surface resin layer of the polyethylene resin layer. By containing the compatibilizer in the layer in contact with the surface resin layer of the polyethylene resin layer, the above-mentioned effects can be further improved.

[0044] The compatibilizer can be appropriately selected and used from conventionally known agents, but from the viewpoint of recyclability, unsaturated carboxylic acid-modified polyolefin resins are preferred, and among these, maleic anhydride-modified polyethylene resins are more preferred.

[0045] The content of the compatibilizer in the layer containing the compatibilizer is preferably 5% by mass or more and 30% by mass or less. By setting the content of the compatibilizer in the polyethylene resin layer to 5% by mass or more, the above effects can be further improved. By setting the content of the compatibilizer in the polyethylene resin layer to 30% by mass or less, the strength and heat resistance of the substrate can be improved.

[0046] As long as the properties of the present invention are not impaired, the polyethylene resin layer may contain a resin material other than polyethylene resin, for example, a polyolefin resin such as polypropylene resin, a (meth)acrylic resin, a vinyl resin, a cellulose resin, a polyamide resin, a polyester resin, and an ionomer resin. From the viewpoint of recyclability, it is particularly preferable that the polyethylene resin layer does not contain any resin other than polyethylene resin.

[0047] Furthermore, the polyethylene resin layer may contain additives, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins, as long as the additives do not impair the properties of the present invention.

[0048] The polyethylene resin layer included in the substrate may have a single-layer structure or a multi-layer structure.

[0049] In the polyethylene resin layer having a multilayer structure, the density of the polyethylene resin constituting each layer may be different, that is, the polyethylene resin layer may have a density gradient. By providing a density gradient in the polyethylene resin layer, the strength, heat resistance and stretchability thereof are significantly improved.

[0050] In a polyethylene resin layer with a density gradient, if the density difference between the layers is large, delamination may occur at the interface. Therefore, the density difference between the layers should be 0.04 g / cm 3 Preferably, it is 0.02 g / cm or less.3 It is even more preferable that:

[0051] The following are examples of the polyethylene resin layer having a density gradient, but the configuration of the polyethylene resin layer is not limited to these.

[0052] In one embodiment, the polyethylene resin layer having a density gradient is composed of three layers: a layer containing a high-density polyethylene resin, a layer containing a medium-density polyethylene resin, and a layer containing a high-density polyethylene resin. By configuring the polyethylene resin layer as a three-layer structure with the density gradient as described above, the strength, heat resistance, and stretchability are significantly improved, and the occurrence of curling in the substrate can be effectively prevented.

[0053] In one embodiment, the polyethylene resin layer having a density gradient is composed of five layers: a layer containing high-density polyethylene, a layer containing medium-density polyethylene resin, a layer containing at least one of low-density polyethylene resin and linear low-density polyethylene resin, a layer containing medium-density polyethylene resin, and a layer containing high-density polyethylene resin. By configuring the polyethylene resin layers in a five-layer structure with the density gradient as described above, the strength, heat resistance, and stretchability are significantly improved, and the occurrence of curling in the substrate can be effectively prevented. The polyethylene resin layer having such a structure can be stably produced by the inflation method as described below. Specifically, a high-density polyethylene resin, a medium-density polyethylene resin, and at least one of a low-density polyethylene resin and a linear low-density polyethylene resin are co-extruded from the outside into a tubular shape, Next, the layers containing at least one of the low-density polyethylene resin and the linear low-density polyethylene resin are pressure-bonded together using a rubber roll or the like, thereby completing the production of the laminate. By using such a method, the number of defective products in the manufacturing process can be significantly reduced, and ultimately production efficiency can be improved.

[0054] In one embodiment, the polyethylene resin layer having a density gradient is composed of seven layers: a layer containing a high-density polyethylene resin, a layer containing a blend resin of a high-density polyethylene resin and a medium-density polyethylene resin, a layer containing at least one of a low-density polyethylene resin and a linear low-density polyethylene resin, a layer containing a blend resin of a high-density polyethylene resin and a medium-density polyethylene resin, and a layer containing a high-density polyethylene resin. By configuring the polyethylene resin layer as a five-layer structure with the density gradient as described above, the strength, heat resistance, and stretchability are significantly improved. Furthermore, the occurrence of curling in the substrate can be effectively prevented. Furthermore, the occurrence of delamination in the substrate can be effectively prevented. Moreover, the polyethylene resin layer having such a structure can be stably produced by the inflation method described above.

[0055] The thickness of the polyethylene resin layer is preferably 10 μm or more and 50 μm or less, and more preferably 10 μm or more and 40 μm or less. By making the thickness of the polyethylene resin layer 10 μm or more, the strength and heat resistance of the substrate can be further improved. Furthermore, by setting the thickness of the polyethylene resin layer to 50 μm or less, the film-forming properties and processability of the substrate can be further improved.

[0056] The polyethylene resin layer may have a printed layer on its surface, and the image formed on the printed layer is not particularly limited, and may be a letter, a pattern, a symbol, or a combination thereof. The printing layer on the substrate can be formed using ink derived from biomass, which reduces the environmental impact. The method for forming the printed layer is not particularly limited, and examples thereof include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing.

[0057] (Surface resin layer) The substrate of the laminate comprises a surface resin layer on a polyethylene resin layer, the surface resin layer containing a resin material with a melting point of 150° C. or higher (hereinafter sometimes referred to as a high-melting-point resin material).

[0058] The melting point of the high-melting-point resin material is more preferably 160° C. or higher. By setting the melting point of the high-melting-point resin material to 160°C or higher, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties can be further improved. In addition, when a sealant layer is laminated, the adhesion to the sealant layer can be improved, and the laminate strength of the packaging container made from this laminate can be further improved.

[0059] The melting point of the high-melting-point resin material is preferably 265° C. or less, more preferably 260° C. or less, and even more preferably 250° C. or less. By setting the melting point of the high-melting-point resin material to 265° C. or less, the film-forming properties of the substrate can be improved.

[0060] The difference between the melting point of the high-melting-point resin material contained in the surface resin layer and the melting point of the polyethylene contained in the polyethylene resin layer is preferably 20 to 80°C, more preferably 20 to 60°C. When the difference in melting point between the high-melting-point resin material contained in the surface resin layer and the polyethylene contained in the polyethylene resin layer is 20°C or more, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties of the substrate on which the vapor-deposited film is formed can be further improved. In addition, when a sealant layer is laminated, the adhesion to the sealant layer can be improved, and the laminate strength of the packaging container made from this laminate can be further improved. Furthermore, by making the difference between the melting point of the high-melting-point resin material contained in the surface resin layer and the melting point of the polyethylene contained in the polyethylene resin layer 80° C. or less, the film-forming properties of the substrate can be further improved.

[0061] In one embodiment, the high-melting-point resin material is made of a polymer having a polar group. By making the high-melting-point resin material made of a polymer having a polar group, it is possible to further improve adhesion to the vapor-deposited film.

[0062] In the present invention, the polar group refers to a group containing one or more heteroatoms, and examples thereof include an ester group, an epoxy group, a hydroxyl group, an amino group, an amide group, a carboxyl group, a carbonyl group, a carboxylic anhydride group, a sulfone group, a thiol group, and a halogen group. Among these, from the viewpoint of the laminate strength of the packaging container, hydroxyl group, ester group, amino group, amide group, carboxyl group and carbonyl group are preferred, and hydroxyl group is more preferred.

[0063] Examples of high-melting-point resin materials include vinyl resins, polyamides, polyimides, polyesters, (meth)acrylic resins, cellulose resins, polyolefin resins, and ionomer resins.

[0064] In the present invention, resin materials having a melting point of 150°C or higher and having a polar group are particularly preferred, and amide resins such as ethylene vinyl alcohol copolymer, polyvinyl alcohol, nylon 6, nylon 6,6, nylon 6-nylon 6,6 copolymer, MXD nylon, and amorphous nylon are preferred, with ethylene vinyl alcohol copolymer and amide resins being particularly preferred. By using such a resin material, the adhesion of the vapor-deposited film formed on the surface resin layer can be significantly improved, and the gas barrier properties can be effectively improved.

[0065] The content of the high-melting-point resin material in the surface resin layer is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. By making the content of the high-melting-point resin material in the surface resin layer 70% by mass or more, the adhesion of the vapor-deposited film formed on the surface resin layer can be significantly improved, and the gas barrier properties of the substrate on which the vapor-deposited film is formed can be effectively improved.

[0066] The surface resin layer may contain a resin material other than the high-melting-point resin material as long as the characteristics of the present invention are not impaired. From the viewpoint of adhesion to the vapor-deposited film, it is preferable that the surface resin layer does not contain any resin material other than the high-melting-point resin material.

[0067] Furthermore, the surface resin layer may contain additives, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins, as long as the additives do not impair the properties of the present invention.

[0068] The thickness of the surface resin layer is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 4 μm or less. By making the thickness of the surface resin layer 0.1 μm or more, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties of the substrate on which the vapor-deposited film is formed can be further improved. Furthermore, when a sealant layer is laminated, the adhesion to the sealant layer can be improved, and the laminate strength of the packaging container made from this laminate can be further improved. Furthermore, by making the thickness of the surface resin layer 5 μm or less, the substrate can be suitably used for producing mono-material packaging containers, and the film-forming properties and processability of the substrate can be further improved.

[0069] The surface resin layer of the substrate may be subjected to a surface treatment, which can improve adhesion to adjacent layers. The surface treatment method is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

[0070] The thickness of the surface resin layer is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 4 μm or less. By making the thickness of the surface resin layer 0.1 μm or more, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties of the substrate on which the vapor-deposited film is formed can be further improved. Furthermore, when a sealant layer is laminated, the adhesion to the sealant layer can be improved, and the laminate strength of the packaging container made from this laminate can be further improved. Furthermore, by making the thickness of the surface resin layer 5 μm or less, the substrate can be suitably used for producing mono-material packaging containers, and the film-forming properties and processability of the substrate can be further improved.

[0071] The surface resin layer of the substrate may be subjected to a surface treatment, which can improve adhesion to adjacent layers. The surface treatment method is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

[0072] (adhesive resin layer) In one embodiment, the substrate may include an adhesive resin layer between the polyethylene resin layer and the surface resin layer, thereby improving adhesion between these layers.

[0073] The adhesive resin layer can be formed by using an adhesive resin such as polyether, polyester, silicone resin, epoxy resin, polyurethane, vinyl resin, phenolic resin, and polyolefin. Among the above, polyolefins and acid-modified products thereof are preferred, and polyethylene and acid-modified products thereof are particularly preferred, since they can give the laminate a structure more suitable for mono-material packaging containers. As the adhesive polyethylene, commercially available products can be used, for example, the Admer series manufactured by Mitsui Chemicals, Inc.

[0074] The thickness of the adhesive resin layer is not particularly limited, but can be, for example, 1 μm or more and 15 μm or less. By making the thickness of the adhesive resin layer 1 μm or more, the adhesion between the polyethylene resin layer and the surface resin layer can be further improved. By making the thickness of the adhesive layer 15 μm or less, the processability of the substrate can be improved.

[0075] The substrate is subjected to a stretching treatment, and the stretching treatment may be uniaxial stretching or biaxial stretching. The stretching ratio in the machine direction (MD direction) and the transverse direction (TD direction) of the substrate is preferably 2 times or more and 15 times or less, and more preferably 5 times or more and 13 times or less. By stretching the film at a ratio of 2 or more, the strength and heat resistance of the substrate can be further improved, and the printability of the substrate can also be improved. From the viewpoint of the breaking limit of the substrate, the stretching ratio is preferably 15 times or less.

[0076] In one embodiment, the substrate is a co-extruded film, which can be produced by forming a resin film using a T-die method, an inflation method, or the like, and then stretching the film. By forming the film by the inflation method, the resin film can be stretched at the same time.

[0077] (evaporated film) The laminate has a vapor-deposited film on and adjacent to the surface resin layer. In the laminate, the vapor-deposited film and the surface resin layer have high adhesion to each other, and the laminate has extremely high gas barrier properties, specifically oxygen barrier properties and water vapor barrier properties. Furthermore, since the laminate has a vapor-deposited film, a packaging container made using the laminate can suppress a loss in mass of the contents filled therein.

[0078] The vapor-deposited film can be a vapor-deposited film of one or more inorganic substances or inorganic oxides such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc. The vapor-deposited film can be composed of two or more layers, and may be composed of the same material or different materials. Among the above, from the viewpoints of adhesion to the surface resin layer and gas barrier properties, the vapor-deposited film is preferably made of aluminum, aluminum oxide (alumina) or silicon oxide (silica).

[0079] The surface of the deposited film is preferably subjected to the above-mentioned surface treatment, which can improve adhesion to adjacent layers.

[0080] The thickness of the vapor-deposited film is preferably 1 nm or more and 150 nm or less, more preferably 5 nm or more and 60 nm or less, and even more preferably 10 nm or more and 40 nm or less. By making the thickness of the vapor-deposited film 1 nm or more, the oxygen barrier property and water vapor barrier property of the laminate can be further improved. Furthermore, by making the thickness of the vapor-deposited film 150 nm or less, it is possible to obtain a laminate that can be suitably used for producing mono-material packaging containers, and further, it is possible to prevent the occurrence of cracks in the vapor-deposited film.

[0081] The vapor-deposited film can be formed by a conventionally known method, such as a physical vapor deposition method (PVD method) such as vacuum deposition, sputtering, or ion plating, or a chemical vapor deposition method (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, or photochemical vapor deposition. Hereinafter, one embodiment of the method for forming the vapor-deposited film will be described, but the method for forming the vapor-deposited film is not limited to this.

[0082] A plasma-assisted vacuum film-forming apparatus can be used as an apparatus for forming a vapor-deposited film by the PVD method. An embodiment of a method for forming a vapor-deposited film using a plasma-assisted vacuum film-forming apparatus will be described below. In one embodiment, as shown in Figures 5 and 6, the vacuum film formation apparatus includes a vacuum vessel A, a substrate 10, an unwinding section B, a film formation drum C, a winding section D, a transport roll E, an evaporation source F, a reaction gas supply section G, an adhesion-proof box H, an evaporation material I, and a plasma gun J. 5 is a schematic cross-sectional view of the vacuum film-forming apparatus in the XZ plane direction, and FIG. 6 is a schematic cross-sectional view of the vacuum film-forming apparatus in the XY plane direction. As shown in Figure 5, the substrate 10 wound around the film-forming drum C is placed in the upper part of the vacuum chamber A with its surface resin layer facing downward, and an electrically grounded deposition-protective box H is placed below the film-forming drum C in the vacuum chamber A. An evaporation source F is placed on the bottom of the deposition-protective box H. The film-forming drum C is placed in the vacuum chamber A so that the surface resin layer of the substrate 10 wound around the film-forming drum C is positioned opposite the top surface of the evaporation source F with a certain gap between them. Further, transport rolls E are arranged between the unwinding section B and the film-forming drum C, and between the film-forming drum C and the winding section D. The vacuum vessel is connected to a vacuum pump (not shown). The evaporation source F is for holding the evaporation material I and is equipped with a heating device (not shown). The reactive gas supply unit G is a portion that supplies a reactive gas (oxygen, nitrogen, helium, argon, a mixed gas of these, etc.) that reacts with the evaporated deposition material. The vapor deposition material I is heated and evaporated from the evaporation source F and directed onto the surface resin layer of the substrate 10, and at the same time, plasma is also directed from the plasma gun J toward the surface resin layer, forming a vapor deposition film. Details of this formation method are disclosed in Japanese Patent Application Laid-Open No. 2011-214089.

[0083] The plasma generating device used in plasma chemical vapor deposition can be a device that generates high-frequency plasma, pulsed wave plasma, microwave plasma, or the like. A device having two or more film formation chambers can also be used. It is preferable that the device is equipped with a vacuum pump so that each film formation chamber can be maintained under vacuum. The vacuum level in each deposition chamber was 1×10 to 1×10 -6 Pa is preferred. An embodiment of a method for forming a vapor-deposited film using a plasma generating device will be described below. First, the substrate is sent into the film-forming chamber and transported onto the cooling electrode drum at a predetermined speed via an auxiliary roll. Next, a mixed gas composition containing a film-forming monomer gas containing an inorganic oxide, oxygen gas, an inert gas, etc. is supplied from the gas supply device into the film-forming chamber, and plasma is generated on the surface resin layer by glow discharge, which is then irradiated to form a vapor-deposited film containing an inorganic oxide on the surface resin layer. Details of this formation method are disclosed in Japanese Patent Application Laid-Open No. 2012-076292.

[0084] As an apparatus used in the method for forming a vapor-deposited film, a continuous vapor-deposited film-forming apparatus equipped with a plasma pretreatment chamber and a film-forming chamber can be used. An embodiment of a method for forming a vapor-deposited film using the apparatus will be described below. First, in the plasma pretreatment chamber, plasma is irradiated onto the surface resin layer of the substrate from a plasma supply nozzle, and then, in the film formation chamber, a vapor deposition film is formed on the plasma-treated surface resin layer. Details of this formation method are disclosed in International Publication WO2019 / 087960.

[0085] (barrier coat layer) The laminate may further include a barrier coating layer on the vapor-deposited film, thereby improving the oxygen barrier property and water vapor barrier property of the laminate.

[0086] In one embodiment, the barrier coat layer comprises a gas barrier resin such as ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, polyamide resin such as nylon 6, nylon 6,6 and polymetaxylylene adipamide (MXD6), polyester resin, polyurethane resin, and (meth)acrylic resin.

[0087] The content of the gas barrier resin in the barrier coat layer is preferably 50% by mass or more and 95% by mass or less, and more preferably 75% by mass or more and 90% by mass or less. By making the content of the gas barrier resin in the barrier coat layer 50% by mass or more, it is possible to further improve the oxygen barrier property and water vapor barrier property.

[0088] The thickness of the barrier coat layer is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less. By making the thickness of the barrier coat layer 0.01 μm or more, the oxygen barrier property and water vapor barrier property of the laminate can be further improved. By making the thickness of the barrier coat layer 10 μm or less, the processability of the laminate can be improved. Furthermore, the recyclability of packaging containers made using a laminate of a substrate and a sealant layer made of polyethylene resin can be improved.

[0089] The barrier coat layer can be formed by dissolving or dispersing the above-mentioned material in water or an appropriate solvent, applying the solution, and drying. Alternatively, the barrier coat layer can be formed by applying a commercially available barrier coating agent and drying it.

[0090] In another embodiment, the barrier coat layer is a gas barrier coating film containing at least one resin composition such as a hydrolyzate of a metal alkoxide or a hydrolyzed condensate of a metal alkoxide obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer by a sol-gel method in the presence of a sol-gel catalyst, water, an organic solvent, etc. By providing such a barrier coating layer on the vapor-deposited film, it is possible to effectively prevent cracks from occurring in the vapor-deposited film.

[0091] In one embodiment, the metal alkoxide is represented by the following general formula: R 1 n M(OR 2 ) m (wherein, R 1 , R 2 each represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the valence of M.

[0092] As the metal atom M, for example, silicon, zirconium, titanium, aluminum, etc. can be used. Also, R 1 and R 2 Examples of the organic group represented by the formula (I) include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group.

[0093] Examples of metal alkoxides that satisfy the above general formula include tetramethoxysilane (Si(OCH3)4), tetraethoxysilane (mass %) Si(OC2H5)4), tetrapropoxysilane (Si(OC3H7)4), and tetrabutoxysilane (Si(OC4H9)4).

[0094] It is also preferable to use a silane coupling agent together with the metal alkoxide. As the silane coupling agent, known organoalkoxysilanes containing organic reactive groups can be used.

[0095] As the water-soluble polymer, polyvinyl alcohol and ethylene-vinyl alcohol copolymer are preferred, and from the viewpoints of oxygen barrier property, water vapor barrier property, water resistance and weather resistance, it is preferred to use these in combination.

[0096] The thickness of the gas barrier coating film is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less. By making the thickness of the gas barrier coating film 0.01 μm or more, the oxygen barrier property and water vapor barrier property of the laminate can be improved, and the occurrence of cracks in the vapor-deposited film can be prevented. By setting the thickness of the gas barrier coating film to 10 μm or less, it is possible to obtain a laminate that can be suitably used for producing mono-material packaging containers.

[0097] The gas barrier coating film can be formed by applying a composition containing the above-mentioned materials by a conventionally known means such as roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brush coating, bar coating, or applicator coating, and then polycondensing the composition by a sol-gel method. As the catalyst for the sol-gel method, an acid or an amine compound is suitable.

[0098] The composition may further contain an acid, which is used as a catalyst in the sol-gel process, mainly for the hydrolysis of alkoxides, silane coupling agents, and the like. As the acid, mineral acids such as sulfuric acid, hydrochloric acid, nitric acid, etc., and organic acids such as acetic acid, tartaric acid, etc. can be used.

[0099] The composition may also contain an organic solvent, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, or n-butanol.

[0100] An embodiment of the method for forming a gas barrier coating film will be described below. First, a composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and optionally a silane coupling agent, etc. A polycondensation reaction gradually proceeds in the composition. Next, the composition is applied onto the vapor-deposited film by the above-mentioned conventionally known method and dried, which further promotes the polycondensation reaction of the alkoxide and the water-soluble polymer (and the silane coupling agent, if the composition contains one) to form a composite polymer layer. Finally, the coating is heated to form a gas barrier coating film.

[0101] (sealant layer) In one embodiment, the sealant layer contains the same resin as the polyethylene resin layer of the substrate, i.e., polyethylene resin. A laminate having such a configuration can be suitably used as a laminate for producing a mono-material packaging container. As the polyethylene resin, high density polyethylene resin (HDPE), medium density polyethylene resin (MDPE), low density polyethylene resin (LDPE), linear low density polyethylene resin (LLDPE), and very low density polyethylene resin (VLDPE) can be used. Furthermore, a copolymer of ethylene and other monomers can also be used as the polyethylene resin. Furthermore, as the polyethylene resin, a biomass-derived polyethylene resin or a mechanically recycled or chemically recycled polyethylene resin can also be used.

[0102] The content of polyethylene resin in the sealant layer is preferably 80% by mass or more, and more preferably 90% by mass or more, which makes it possible to obtain a laminate that can be suitably used for producing mono-material packaging containers.

[0103] As long as the properties of the present invention are not impaired, the sealant layer may contain a resin material other than polyethylene resin, for example, polyolefin resin such as polypropylene resin, (meth)acrylic resin, vinyl resin, cellulose resin, polyamide resin, polyester resin, and ionomer resin. From the viewpoint of recyclability, it is particularly preferable that the sealant layer does not contain any resin other than polyethylene resin.

[0104] The sealant layer may contain the above-mentioned additives as long as the properties of the present invention are not impaired.

[0105] The sealant layer may have a single-layer structure or a multi-layer structure.

[0106] The thickness of the sealant layer is preferably 20 μm or more and 100 μm or less, and more preferably 30 μm or more and 70 μm or less. By making the thickness of the sealant layer 20 μm or more, the laminate strength of the packaging container can be further improved. Furthermore, by setting the thickness of the sealant layer to 100 μm or less, the moldability of the laminate can be improved, and the packaging container can be produced more easily.

[0107] The sealant layer can be formed by laminating a resin film made of the above-mentioned resin material, such as polyethylene resin, onto a vapor-deposited film provided on the surface vapor-deposited film or onto a barrier coat layer via a conventionally known adhesive or the like. The sealant layer can also be formed by melt-extruding the resin material onto the vapor-deposited film provided on the surface vapor-deposited film or onto the barrier coat layer. When the laminate is used to produce a laminate tube or the like, the laminate 50 further comprises a sealant layer 53 (not shown) on the surface of the substrate 51 on which no vapor-deposited film is formed.

[0108] (Adhesive layer) The laminate may include an adhesive layer between any of the layers. The adhesive layer contains at least one adhesive, and the adhesive may be a one-component curing type, a two-component curing type, or a non-curing type. The adhesive may be a solvent-free adhesive or a solvent-based adhesive, but from the viewpoint of environmental load, a solvent-free adhesive is preferably used. Examples of solvent-free adhesives include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives, and among these, two-component curing urethane adhesives can be preferably used. Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives.

[0109] The thickness of the adhesive layer is preferably 1 μm or more and 15 μm or less, and more preferably 3 μm or more and 10 μm or less. By making the thickness of the adhesive layer 1 μm or more, it is possible to improve the adhesion between the layers. Furthermore, by making the thickness of the adhesive layer 15 μm or less, it is possible to improve the recyclability of the packaging bag.

[0110] (Laminate according to the second aspect) As shown in FIG. 7, the laminate 60 includes a substrate 61, an intermediate layer 62, and a sealant layer 63, and the intermediate layer 62 includes a vapor-deposited film 64, a surface resin layer 65, and a polyethylene resin layer 66. The intermediate polyethylene resin layer, the substrate, and the sealant layer of the laminate are all made of the same resin, i.e., polyethylene resin, and a laminate having such a configuration can be suitably used as a laminate for producing mono-material packaging containers.

[0111] The content of polyethylene resin relative to the total amount of solids contained in the laminate constituting the packaging bag is preferably 80% by mass or more, more preferably 90% by mass or more, which makes it possible to obtain a laminate that can be suitably used for producing mono-material packaging containers (packaging bags).

[0112] Although Figure 7 shows a configuration in which the vapor deposition film 64 and the substrate 61 are adjacent to each other, this is not limited to this, and the vapor deposition film 64 may be adjacent to the sealant layer 63, as shown in Figure 8.

[0113] From the viewpoint of the heat sealability of the packaging bag of the present invention produced from the barrier laminate 60, it is preferable that the vapor-deposited film 14 be provided adjacent to the substrate 51 as shown in FIG.

[0114] In one embodiment, the intermediate layer 62 may further include an adhesive resin layer 67 between the surface resin layer 65 and the polyethylene resin layer 66, as shown in FIG.

[0115] Additionally, in one embodiment, stack 60 includes a barrier coat layer (not shown) adjacent to deposited film 64 .

[0116] Furthermore, in one embodiment, the laminate 60 includes adhesive layers (not shown) between any of the layers, for example, between the substrate 61 and the intermediate layer 62, or between the intermediate layer 62 and the sealant layer 63.

[0117] Hereinafter, each layer included in the laminate according to the second embodiment will be described.

[0118] (base material) The substrate contains the same resin as the polyethylene resin layer of the intermediate layer and the sealant layer, i.e., polyethylene resin. A laminate having such a configuration can be suitably used as a laminate for producing a mono-material packaging container. As the polyethylene resin, high density polyethylene resin (HDPE), medium density polyethylene resin (MDPE), low density polyethylene resin (LDPE), linear low density polyethylene resin (LLDPE), and very low density polyethylene resin (VLDPE) can be used. Furthermore, a copolymer of ethylene and other monomers can also be used as the polyethylene resin. Furthermore, as the polyethylene resin, a biomass-derived polyethylene resin or a mechanically recycled or chemically recycled polyethylene resin can also be used.

[0119] The content of polyethylene resin in the substrate is preferably 80% by mass or more, and more preferably 90% by mass or more, which makes it possible to obtain a laminate that can be suitably used for producing mono-material packaging containers.

[0120] As long as the properties of the present invention are not impaired, the substrate may contain a resin material other than polyethylene resin, and examples thereof include polyolefin resins such as polypropylene resins, (meth)acrylic resins, vinyl resins, cellulose resins, polyamide resins, polyester resins, and ionomer resins. From the viewpoint of recyclability, it is particularly preferable that the substrate does not contain any resin other than polyethylene resin.

[0121] The substrate may contain the above-mentioned additives as long as the characteristics of the present invention are not impaired.

[0122] The substrate may have a single layer structure or a multilayer structure.

[0123] In a substrate having a multilayer structure, the polyethylene resin constituting each layer may have a different density, that is, the substrate may have a density gradient. By providing a density gradient in the substrate, the strength, heat resistance and stretchability of the substrate are significantly improved.

[0124] In a substrate with a density gradient, if the density difference between the layers is large, delamination may occur at the interface. Therefore, the density difference between the layers should be less than 0.04 g / cm. 3 Preferably, it is 0.02 g / cm or less. 3 It is even more preferable that:

[0125] The specific configuration of the base material having a concentration gradient is the same as that of the polyethylene resin layer having a concentration gradient shown in the first embodiment, and therefore will not be described here.

[0126] In one embodiment, the substrate is subjected to a stretching treatment, and the stretching treatment may be uniaxial stretching or biaxial stretching. The stretching ratio in the machine direction (MD direction) and the transverse direction (TD direction) of the substrate is preferably 2 times or more and 15 times or less, and more preferably 5 times or more and 13 times or less. By stretching the film at a ratio of 2 or more, the strength and heat resistance of the substrate can be further improved, and the printability of the substrate can also be improved. From the viewpoint of the breaking limit of the substrate, the stretching ratio is preferably 15 times or less.

[0127] The substrate may have a printed layer on its surface, and the image formed on the printed layer is not particularly limited, and may be a letter, a pattern, a symbol, or a combination thereof. The printing layer can be formed using ink derived from biomass, which reduces the environmental impact. The method for forming the printed layer is not particularly limited, and examples thereof include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing.

[0128] The substrate is preferably subjected to a surface treatment, which can improve adhesion to adjacent layers. The surface treatment method is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals. Alternatively, an anchor coating layer may be formed on the surface of the substrate using a conventionally known anchor coating agent.

[0129] The thickness of the substrate is preferably 9 μm or more and 50 μm or less, and more preferably 12 μm or more and 30 μm or less. By setting the thickness of the substrate within the above numerical range, the printability, strength, and heat resistance of the substrate can be further improved.

[0130] (middle class) The intermediate layer includes a vapor-deposited film, a surface resin layer, and a polyethylene resin layer. In one embodiment, an adhesive resin layer is provided between the surface resin layer and the polyethylene resin layer. The intermediate layer may be provided so that the surface on which the vapor-deposited film is formed faces the substrate side, or so that it faces the sealant layer side. However, from the viewpoint of the heat sealability of the packaging bag of the present invention produced using the barrier laminate, it is preferable that the intermediate layer be provided so that the surface on which the vapor-deposited film is formed faces the substrate side.

[0131] The surface resin layer, the polyethylene resin layer and the adhesive resin layer are subjected to a stretching treatment, and the stretching treatment may be uniaxial stretching or biaxial stretching. The stretching ratio in the machine direction (MD direction) and the transverse direction (TD direction) is preferably 2 times or more and 15 times or less, and more preferably 5 times or more and 13 times or less. By stretching the film at a ratio of 2 or more, the strength and heat resistance of the intermediate layer can be further improved, and the printability of the intermediate layer can also be improved. From the viewpoint of the breaking limit, the stretching ratio is preferably 15 times or less.

[0132] In one embodiment, the surface resin layer and the polyethylene resin layer of the intermediate layer are co-extruded films, which can be produced by forming a resin film using a T-die method, an inflation method, or the like, and then stretching it. By forming the film by the inflation method, the resin film can be stretched at the same time.

[0133] (Polyethylene resin layer) The configuration of the polyethylene resin layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0134] (Surface resin layer) The configuration of the surface resin layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0135] (adhesive resin layer) The structure of the adhesive resin layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0136] (evaporated film) The configuration of the vapor-deposited film is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0137] (barrier coat layer) The configuration of the barrier coat layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0138] (sealant layer) The configuration of the sealant layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0139] (Adhesive layer) The structure of the adhesive layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0140] (Laminate according to the third aspect) As shown in FIG. 11, the laminate 70 includes a substrate 71, a vapor-deposited film 72, and a sealant layer 73, and the sealant layer 73 includes a surface resin layer 74 and a polyethylene resin layer 75. The polyethylene resin layer of the sealant layer of the laminate and the substrate contain the same resin, i.e., polyethylene resin, and a laminate having such a configuration can be suitably used as a laminate for producing mono-material packaging containers.

[0141] The content of polyethylene resin relative to the total amount of solids contained in the laminate constituting the packaging bag is preferably 80% by mass or more, more preferably 90% by mass or more, which makes it possible to obtain a laminate that can be suitably used for producing mono-material packaging containers (packaging bags).

[0142] In one embodiment, the sealant layer 73 may further include an adhesive resin layer 76 between the surface resin layer 74 and the polyethylene resin layer 75, as shown in FIG.

[0143] Additionally, in one embodiment, stack 70 includes a barrier coat layer (not shown) adjacent to deposited film 72 .

[0144] Additionally, in one embodiment, laminate 70 includes an adhesive layer (not shown) between any of the layers, for example, between vapor-deposited film 72 and sealant layer 73 .

[0145] Each layer of the laminate according to the third embodiment will be described below.

[0146] (base material) The configuration of the substrate is the same as that of the laminate of the second embodiment, and therefore a description thereof will be omitted here.

[0147] (evaporated film) The configuration of the vapor-deposited film is the same as that of the laminate of the first and second embodiments, and therefore a description thereof will be omitted here.

[0148] (sealant layer) The sealant layer includes a surface resin layer and a polyethylene resin layer, and in one embodiment, an adhesive resin layer is provided between the surface resin layer and the polyethylene resin layer.

[0149] In one embodiment, the sealant layer is a co-extruded film, and can be produced by film formation using a T-die method, an inflation method, or the like.

[0150] From the viewpoint of heat sealing properties, the sealant layer is preferably made of an unstretched film.

[0151] (Polyethylene resin layer) The configuration of the polyethylene resin layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0152] (Surface resin layer) The configuration of the surface resin layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0153] (adhesive resin layer) The structure of the adhesive resin layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0154] (barrier coat layer) The configuration of the barrier coat layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here.

[0155] (Adhesive layer) The structure of the adhesive layer is the same as that of the laminate of the first embodiment, and therefore a description thereof will be omitted here. [Example]

[0156] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0157] Example 1-1 Ethylene vinyl alcohol copolymer (Kuraray Co., Ltd., EVAL E171B, melting point: 165°C, density: 1.14 g / cm 3 )and, Adhesive resin (Mitsui Chemicals, Inc., maleic anhydride-modified polyethylene, Admer NF557, density 0.920 g / cm 3 )and, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and The mixture was co-extruded by inflation molding to form a film, which was then stretched 5 times in the machine direction (MD) using a stretching device to prepare a substrate. In the substrate thus obtained, the surface resin layer made of ethylene-vinyl alcohol copolymer had a thickness of 2 μm, the adhesive resin layer had a thickness of 3 μm, and the polyethylene resin layer made of medium-density polyethylene had a thickness of 20 μm.

[0158] The surface of the surface resin layer of the substrate is coated with PVD method at a pressure of 3.0 × 10 -2 An aluminum vapor deposition film with a thickness of 30 nm was formed under the conditions of 20 Pa.

[0159] First, linear low-density polyethylene (Prime Polymer Co., Ltd., SP2520, density: 0.925 g / cm 3 A multilayer extrusion film was formed from a first linear low-density polyethylene (SP1520, manufactured by Prime Polymer Co., Ltd., density 0.913, melting point 116°C) and a second linear low-density polyethylene (SP1520, manufactured by Prime Polymer Co., Ltd., density 0.913, melting point 116°C) by inflation molding to produce an unstretched polyethylene film having a thickness of 20 μm for the first linear low-density polyethylene and a thickness of 20 μm for the second linear low-density polyethylene. The first linear low-density polyethylene side of this unstretched polyethylene film was laminated onto the aluminum vapor deposition film of the substrate formed above using a two-component curing urethane adhesive (Ru-77T / H-7, manufactured by Rock Paint Co., Ltd.) to obtain a laminate. The polyethylene content in the laminate is summarized in Table 1. Table 1 also summarizes the laminates obtained in the following Examples and Comparative Examples and the polyethylene content in the laminates.

[0160] Example 1-2 Ethylene vinyl alcohol copolymer was used as a polyamide (Ube Industries, Ltd., 5033, melting point: 196°C, density: 1.14 g / cm 3 A substrate was produced in the same manner as in Example 1-1, except that the above-mentioned step (1) was changed to the above-mentioned step (2). In the substrate thus obtained, the surface resin layer made of polyamide had a thickness of 2 μm, the adhesive resin layer had a thickness of 3 μm, and the polyethylene resin layer made of medium-density polyethylene had a thickness of 20 μm.

[0161] A laminate was produced in the same manner as in Example 1-1, except that the substrate was changed to the substrate produced as described above.

[0162] Examples 1-3 Ethylene vinyl alcohol copolymer (Kuraray Co., Ltd., EVAL E171B, melting point: 165°C, density: 1.14 g / cm 3 )and, Adhesive resin (Mitsui Chemicals, Inc., maleic anhydride-modified polyethylene, Admer NF557, density 0.920 g / cm 3 )and, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and a compatibilizer (Dow Chemical, maleic anhydride polyethylene, Retain 3000, density: 0.87 g / cm 3 ) on a mass basis, a blend resin containing 8:2, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and The mixture was co-extruded by inflation molding to form a film, which was then stretched 5 times in the machine direction (MD) using a stretching device to prepare a substrate. In the substrate thus obtained, the thickness of the surface resin layer composed of ethylene-vinyl alcohol copolymer was 2 μm, the thickness of the adhesive resin layer was 3 μm, the thickness of the second polyethylene resin layer composed of the blend resin was 10 μm, and the thickness of the first polyethylene resin layer composed of medium-density polyethylene was 10 μm.

[0163] A laminate was produced in the same manner as in Example 1-1, except that the substrate was changed to the substrate produced as described above.

[0164] Examples 1-4 Ethylene vinyl alcohol copolymer was used as a polyamide (Ube Industries, Ltd., 5033, melting point: 196°C, density: 1.14 g / cm 3 A substrate was prepared in the same manner as in Example 1-3, except that the above-mentioned step (1) was changed to the above-mentioned step (2). In the substrate thus obtained, the thickness of the surface resin layer composed of polyamide was 2 μm, the thickness of the adhesive resin layer was 3 μm, the thickness of the second polyethylene resin layer composed of the blend resin was 10 μm, and the thickness of the first polyethylene resin layer composed of medium-density polyethylene was 10 μm.

[0165] A laminate was produced in the same manner as in Example 1-1, except that the substrate was changed to the substrate produced as described above.

[0166] Comparative Example 1-1 Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 The polyethylene film was extruded into a single layer by inflation molding, and then stretched 5 times in the machine direction (MD direction) using a stretching device to produce a 25 μm stretched polyethylene film.

[0167] A laminate was produced in the same manner as in Example 1-1, except that the substrate was changed to the stretched polyethylene film produced as described above.

[0168] Comparative Example 1-2 A biaxially stretched polyester film (E5100, manufactured by Toyobo Co., Ltd.) having a thickness of 12 μm was prepared.

[0169] A laminate was produced in the same manner as in Example 1-1, except that the substrate was changed to the above polyester film.

[0170] Example 2-1 A laminate was produced in the same manner as in Example 1-1, except that the aluminum vapor deposition film was changed to an aluminum oxide (alumina) vapor deposition film having a thickness of 20 nm formed by a PVD method.

[0171] Example 2-2 A laminate was produced in the same manner as in Example 1-2, except that the aluminum vapor deposition film was changed to an aluminum oxide (alumina) vapor deposition film having a thickness of 20 nm formed by a PVD method.

[0172] Example 2-3 A laminate was produced in the same manner as in Example 1-3, except that the aluminum vapor deposition film was changed to an aluminum oxide (alumina) vapor deposition film having a thickness of 20 nm formed by a PVD method.

[0173] Examples 2-4 A laminate was produced in the same manner as in Example 1-4, except that the aluminum vapor deposition film was changed to an aluminum oxide (alumina) vapor deposition film having a thickness of 20 nm formed by a PVD method.

[0174] Comparative Example 2-1 A laminate was produced in the same manner as in Comparative Example 1-1, except that the aluminum vapor deposition film was changed to an aluminum oxide (alumina) vapor deposition film having a thickness of 20 nm formed by a PVD method.

[0175] Comparative Example 2-2 A laminate was produced in the same manner as in Comparative Example 1-2, except that the aluminum vapor deposition film was changed to an aluminum oxide (alumina) vapor deposition film having a thickness of 20 nm formed by a PVD method.

[0176] Example 3-1 A laminate was produced in the same manner as in Example 1-1, except that the aluminum vapor deposition film was changed to a silicon oxide (silica) vapor deposition film having a thickness of 20 nm formed by a CVD method.

[0177] Example 3-2 A laminate was produced in the same manner as in Example 1-2, except that the aluminum vapor deposition film was changed to a silicon oxide (silica) vapor deposition film having a thickness of 20 nm formed by a CVD method.

[0178] Example 3-3 A laminate was produced in the same manner as in Example 1-3, except that the aluminum vapor deposition film was changed to a silicon oxide (silica) vapor deposition film having a thickness of 20 nm formed by a CVD method.

[0179] Examples 3-4 A laminate was produced in the same manner as in Example 1-4, except that the aluminum vapor deposition film was changed to a silicon oxide (silica) vapor deposition film having a thickness of 20 nm formed by a CVD method.

[0180] Comparative Example 3-1 A laminate was produced in the same manner as in Comparative Example 1-1, except that the aluminum vapor deposition film was changed to a silicon oxide (silica) vapor deposition film having a thickness of 20 nm formed by a CVD method.

[0181] Comparative Example 3-2 A laminate was produced in the same manner as in Comparative Example 1-2, except that the aluminum vapor deposition film was changed to a silicon oxide (silica) vapor deposition film having a thickness of 20 nm formed by a CVD method.

[0182] Example 4-1 Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 A single layer of the polymer (melting point: 129°C) was extruded by an inflation method and then stretched 5 times in the machine direction (MD direction) using a stretching device to prepare a substrate with a thickness of 25 µm.

[0183] Ethylene vinyl alcohol copolymer (Kuraray Co., Ltd., EVAL E171B, melting point: 165°C, density: 1.14 g / cm 3 )and, Adhesive resin (Mitsui Chemicals, Inc., maleic anhydride-modified polyethylene, Admer NF557, density 0.920 g / cm 3 )and, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and The mixture was co-extruded by inflation molding to form a film, and then stretched 5 times in the machine direction (MD direction) using a stretching device to produce an intermediate layer. In the intermediate layer thus obtained, the surface resin layer made of ethylene-vinyl alcohol copolymer had a thickness of 2 μm, the adhesive resin layer had a thickness of 3 μm, and the polyethylene resin layer made of medium-density polyethylene had a thickness of 20 μm.

[0184] On the surface of the intermediate layer's surface resin layer, a pressure of 3.0 × 10 -2 An aluminum vapor deposition film with a thickness of 30 nm was formed under the conditions of 20 Pa.

[0185] The substrate and the surface on which the vapor-deposited film of the intermediate layer was formed were laminated together via a two-component curing urethane adhesive (Ru-77T / H-7, manufactured by Rock Paint Co., Ltd.).

[0186] Linear low-density polyethylene (Prime Polymer, SP2520, density: 0.925 g / cm 3 The resulting mixture (melting point: 122°C) was extruded into a single layer by a T-die method to prepare an unstretched polyethylene film having a thickness of 40 µm. This unstretched polyethylene film was laminated onto the surface of the intermediate layer on which the vapor-deposited film was not formed via a two-component curing urethane adhesive (Ru-77T / H-7, manufactured by Rock Paint Co., Ltd.) to obtain a laminate. The polyethylene content in the laminate is summarized in Table 2. Table 2 also summarizes the laminates obtained in the following Examples and Comparative Examples and the polyethylene content in the laminates.

[0187] Example 4-2 High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and The mixture was co-extruded by inflation molding to form a film, which was then stretched 5 times in the machine direction (MD) using a stretching device to prepare a substrate. In the substrate thus obtained, the layer made of high-density polyethylene had a thickness of 5 μm, the layer made of medium-density polyethylene had a thickness of 15 μm, and the layer made of high-density polyethylene had a thickness of 5 μm.

[0188] A laminate was produced in the same manner as in Example 4-1, except that the substrate was changed to a substrate having a three-layer structure produced as described above.

[0189] Example 4-3 High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 A blend resin containing 4:6 by mass of ethylenediaminetetraacetic acid (Ethylenediaminetetraacetic acid), propylenediaminetetraacetic acid (Ethylenediaminetetraacetic acid), and propylenediaminetetraacetic acid (Ethylenediaminetetraacetic acid), melting point: 129°C. Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and Ultra-low density polyethylene (Dow Chemical, Affinity EG810G, density: 0.870 g / cm 3 , melting point: 55°C) and The resulting mixture was extruded by inflation molding into a tubular film having, from the outside, a layer made of high-density polyethylene, a layer made of the blend resin, a layer made of medium-density polyethylene, and a layer made of very low-density polyethylene, and the inner layers made of very low-density polyethylene were pressed together using a rubber roll. The film thus obtained had a layer composed of high-density polyethylene, a layer composed of the blend resin, a layer composed of medium-density polyethylene, a layer composed of very low-density polyethylene, a layer composed of medium-density polyethylene, a layer composed of the blend resin, and a layer composed of high-density polyethylene.

[0190] The film obtained as described above was stretched 5 times in the machine direction (MD direction) using a stretching device to prepare a substrate. In the film thus obtained, the layer composed of high-density polyethylene had a thickness of 2.5 μm, the layer composed of the blend resin had a thickness of 2.5 μm, the layer composed of medium-density polyethylene had a thickness of 6.25 μm, the layer composed of ultra-low-density polyethylene had a thickness of 2.5 μm, the layer composed of medium-density polyethylene had a thickness of 6.25 μm, the layer composed of the blend resin had a thickness of 2.5 μm, and the layer composed of high-density polyethylene had a thickness of 2.5 μm.

[0191] A laminate was produced in the same manner as in Example 4-1, except that the substrate was changed to a substrate having a seven-layer structure produced as described above.

[0192] Example 4-4 Ethylene vinyl alcohol copolymer was used as a polyamide (Ube Industries, Ltd., 5033, melting point: 196°C, density: 1.14 g / cm 3 An intermediate layer was produced in the same manner as in Example 4-1, except that the above-mentioned step (1) was changed to the above-mentioned step (2). In the intermediate layer thus obtained, the surface resin layer made of polyamide had a thickness of 2 μm, the adhesive resin layer had a thickness of 3 μm, and the polyethylene resin layer made of medium-density polyethylene had a thickness of 20 μm.

[0193] A laminate was produced in the same manner as in Example 4-1, except that the intermediate layer was changed to the intermediate layer produced as described above.

[0194] Examples 4-5 Ethylene vinyl alcohol copolymer (Kuraray Co., Ltd., EVAL E171B, melting point: 183°C, density: 1.14 g / cm 3 )and, Adhesive resin (Mitsui Chemicals, Inc., Admer NF557) Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and a compatibilizer (Dow Chemical, maleic anhydride polyethylene, Retain 3000, density: 0.87 g / cm 3 ) on a mass basis, a blend resin containing 8:2, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and The mixture was co-extruded by inflation molding to form a film, and then stretched 5 times in the machine direction (MD direction) using a stretching device to produce an intermediate layer. In the intermediate layer thus obtained, the thickness of the surface resin layer composed of ethylene-vinyl alcohol copolymer was 2 μm, the thickness of the adhesive resin layer was 3 μm, the thickness of the second polyethylene resin layer composed of the blend resin was 10 μm, and the thickness of the first polyethylene resin layer composed of medium-density polyethylene was 10 μm.

[0195] A laminate was produced in the same manner as in Example 4-1, except that the intermediate layer was changed to the intermediate layer produced as described above.

[0196] Examples 4-6 Ethylene vinyl alcohol copolymer was used as a polyamide (Ube Industries, Ltd., 5033, melting point: 196°C, density: 1.14 g / cm 3 An intermediate layer was produced in the same manner as in Example 4-5, except that the above-mentioned step (1) was changed to the above-mentioned step (2). In the intermediate layer thus obtained, the thickness of the surface resin layer composed of polyamide was 2 μm, the thickness of the adhesive resin layer was 3 μm, the thickness of the second polyethylene resin layer composed of the blend resin was 10 μm, and the thickness of the first polyethylene resin layer composed of medium-density polyethylene was 10 μm.

[0197] A laminate was produced in the same manner as in Example 4-1, except that the intermediate layer was changed to the intermediate layer produced as described above.

[0198] Comparative Example 4-1 Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 The polyethylene film was extruded into a single layer by inflation molding, and then stretched 5 times in the machine direction (MD direction) using a stretching device to produce a 25 μm stretched polyethylene film.

[0199] A laminate was produced in the same manner as in Example 4-1, except that the intermediate layer was changed to the stretched polyethylene film produced as described above.

[0200] Comparative Example 4-2 A biaxially stretched polyester film (E5100, manufactured by Toyobo Co., Ltd.) having a thickness of 12 μm was prepared.

[0201] A laminate was produced in the same manner as in Example 4-1, except that the intermediate layer was changed to the above polyester film.

[0202] Example 5-1 Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 A single layer of the polymer (melting point: 129°C) was extruded by an inflation method and then stretched 5 times in the machine direction (MD direction) using a stretching device to prepare a substrate with a thickness of 25 µm.

[0203] Ethylene vinyl alcohol copolymer (Kuraray Co., Ltd., EVAL E171B, melting point: 165°C, density: 1.14 g / cm 3 )and, Adhesive resin (Mitsui Chemicals, Inc., maleic anhydride-modified polyethylene, Admer NF557, density 0.920 g / cm 3 )and, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and The mixture was co-extruded by the T-die method to form a sealant layer having a thickness of 40 μm. In the sealant layer thus obtained, the surface resin layer composed of ethylene-vinyl alcohol copolymer had a thickness of 2 μm, the adhesive resin layer had a thickness of 3 μm, and the polyethylene resin layer composed of medium-density polyethylene had a thickness of 35 μm.

[0204] On the surface of the resin layer on the surface of the sealant layer, the PVD method was used, pressure: 3.0 × 10 -2 An aluminum vapor deposition film with a thickness of 30 nm was formed under the conditions of 20 Pa.

[0205] The substrate and the surface of the sealant layer on which the vapor-deposited film was formed were laminated together via a two-component curing urethane adhesive (Ru-77T / H-7, manufactured by Rock Paint Co., Ltd.) to obtain a laminate. The polyethylene content in the laminate is summarized in Table 3. Table 3 also summarizes the laminates obtained in the following Examples and Comparative Examples and the polyethylene content in the laminates.

[0206] Example 5-2 High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and The mixture was co-extruded by inflation molding to form a film, which was then stretched 5 times in the machine direction (MD) using a stretching device to prepare a substrate. In the substrate thus obtained, the layer made of high-density polyethylene had a thickness of 5 μm, the layer made of medium-density polyethylene had a thickness of 15 μm, and the layer made of high-density polyethylene had a thickness of 5 μm.

[0207] A laminate was produced in the same manner as in Example 5-1, except that the substrate was changed to a substrate having a three-layer structure produced as described above.

[0208] Example 5-3 High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm 3 , melting point: 135°C) and medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 A blend resin containing 4:6 by mass of ethylenediaminetetraacetic acid (Ethylenediaminetetraacetic acid), propylenediaminetetraacetic acid (Ethylenediaminetetraacetic acid), and propylenediaminetetraacetic acid (Ethylenediaminetetraacetic acid), melting point: 129°C. Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and Ultra-low density polyethylene (Dow Chemical, Affinity EG810G, density: 0.870 g / cm 3 , melting point: 55°C) and The resulting mixture was extruded by inflation molding into a tubular film having, from the outside, a layer made of high-density polyethylene, a layer made of the blend resin, a layer made of medium-density polyethylene, and a layer made of very low-density polyethylene, and the inner layers made of very low-density polyethylene were pressed together using a rubber roll. The film thus obtained had a layer composed of high-density polyethylene, a layer composed of the blend resin, a layer composed of medium-density polyethylene, a layer composed of very low-density polyethylene, a layer composed of medium-density polyethylene, a layer composed of the blend resin, and a layer composed of high-density polyethylene.

[0209] The film obtained as described above was stretched 5 times in the machine direction (MD direction) using a stretching device to prepare a substrate. In the film thus obtained, the layer composed of high-density polyethylene had a thickness of 2.5 μm, the layer composed of the blend resin had a thickness of 2.5 μm, the layer composed of medium-density polyethylene had a thickness of 6.25 μm, the layer composed of ultra-low-density polyethylene had a thickness of 2.5 μm, the layer composed of medium-density polyethylene had a thickness of 6.25 μm, the layer composed of the blend resin had a thickness of 2.5 μm, and the layer composed of high-density polyethylene had a thickness of 2.5 μm.

[0210] A laminate was produced in the same manner as in Example 5-1, except that the substrate was changed to a substrate having a seven-layer structure produced as described above.

[0211] Example 5-4 Ethylene vinyl alcohol copolymer was used as a polyamide (Ube Industries, Ltd., 5033, melting point: 196°C, density: 1.14 g / cm 3 A sealant layer was prepared in the same manner as in Example 5-1, except that the above-mentioned step (2) was changed to the above-mentioned step (2). In the sealant layer thus obtained, the surface resin layer made of polyamide had a thickness of 2 μm, the adhesive resin layer had a thickness of 3 μm, and the polyethylene resin layer made of medium-density polyethylene had a thickness of 35 μm.

[0212] A laminate was produced in the same manner as in Example 5-1, except that the sealant layer was changed to the sealant layer produced as described above.

[0213] Example 5-5 Ethylene vinyl alcohol copolymer (Kuraray Co., Ltd., EVAL E171B, melting point: 183°C, density: 1.14 g / cm 3 )and, Adhesive resin (Mitsui Chemicals, Inc., Admer NF557) Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and a compatibilizer (Dow Chemical, maleic anhydride polyethylene, Retain 3000, density: 0.87 g / cm 3 ) on a mass basis, a blend resin containing 8:2, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 , melting point: 129°C) and The mixture was co-extruded by the T-die method to form a sealant layer. In the sealant layer thus obtained, the thickness of the surface resin layer composed of ethylene-vinyl alcohol copolymer was 2 μm, the thickness of the adhesive resin layer was 3 μm, the thickness of the second polyethylene resin layer composed of the blend resin was 10 μm, and the thickness of the first polyethylene resin layer composed of medium-density polyethylene was 10 μm.

[0214] A laminate was produced in the same manner as in Example 5-1, except that the sealant layer was changed to the sealant layer produced as described above.

[0215] Examples 5-6 Ethylene vinyl alcohol copolymer was used as a polyamide (Ube Industries, Ltd., 5033, melting point: 196°C, density: 1.14 g / cm 3 A sealant layer was prepared in the same manner as in Example 1-5, except that the above-mentioned step (1) was changed to the above-mentioned step (2). In the sealant layer thus obtained, the thickness of the surface resin layer composed of polyamide was 2 μm, the thickness of the adhesive resin layer was 3 μm, the thickness of the second polyethylene resin layer composed of the blend resin was 10 μm, and the thickness of the first polyethylene resin layer composed of medium-density polyethylene was 10 μm.

[0216] A laminate was produced in the same manner as in Example 5-1, except that the sealant layer was changed to the sealant layer produced as described above.

[0217] Comparative Example 5-1 Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm 3 The resulting mixture (melting point: 129°C) was extruded into a single layer by inflation molding to prepare a 40µm unstretched polyethylene film.

[0218] A laminate was produced in the same manner as in Example 5-1, except that the sealant layer was changed to the unstretched polyethylene film produced as described above.

[0219] <<Gas barrier property evaluation>> The laminates obtained in the examples and comparative examples and the oxygen permeability (cc / m 2 ·day·atm) and water vapor permeability (g / m 2 ·day) was measured by the following method, and the results are summarized in Tables 1 to 3.

[0220] [Oxygen permeability] Using an oxygen permeability measuring device (OX-TRAN2 / 20 manufactured by MOCON), the test piece was set so that the substrate surface was on the oxygen supply side, and the oxygen permeability was measured in an environment of 23°C and a relative humidity of 90% RH in accordance with JIS K 7126. [Water vapor permeability] Using a water vapor permeability measuring device (MOCON, PERMATRAN-w 3 / 33), the test piece was set so that the substrate surface was on the water vapor supply side, and the water vapor permeability was measured in an environment of 40°C and a relative humidity of 90% RH in accordance with JIS K 7129.

[0221] <<Laminate strength test>> The laminates obtained in the above Examples and Comparative Examples, and samples obtained by cutting the laminates into 15 mm wide strips, were measured for lamination strength (N / 15 mm) between the vapor-deposited film and the surface resin layer (Examples), and between the vapor-deposited film and the polyethylene film or polyester film (Comparative Examples) using a tensile tester (Tensilon universal testing machine, manufactured by Orientec Co., Ltd.) in accordance with JIS K6854-2, using a 90° peel (T-peel method) at a peel rate of 50 mm / min. The measurement results are summarized in Tables 1 to 3.

[0222] [Table 1]

[0223] [Table 2]

[0224] [Table 3] [Explanation of symbols]

[0225] 10: packaging bag, 20: standing pouch, 31: easy-opening means, 32: notch portion, 33: half-cut line, 41: extraction nozzle portion, 42: curved portion, 43: cut-out portion, 50: laminate according to first embodiment, 51: substrate, 52: vapor-deposited film, 53: sealant layer, 54: polyethylene resin layer, 55: surface resin layer, 56: adhesive resin layer, 60: laminate according to second embodiment, 61: substrate, 62: intermediate layer, 63: sealant layer, 64: vapor-deposited film, 65: surface resin layer, 66: polyethylene resin layer, 67: adhesive resin layer, 70: laminate according to third embodiment, 71: substrate, 72: vapor-deposited film, 73: sealant layer, 74: surface resin layer, 75: polyethylene resin layer, 76: adhesive resin layer

Claims

1. A packaging bag comprising a laminate including at least a substrate, a vapor-deposited film, and a sealant layer, the substrate comprises at least a polyethylene resin layer and a surface resin layer, the polyethylene resin layer of the substrate has a single layer structure containing medium-density polyethylene, the surface resin layer of the substrate contains a resin material with a melting point of 150°C or higher, The substrate has been subjected to a stretching treatment, the sealant layer is made of a polyethylene resin, the vapor-deposited film is provided on a surface resin layer of the substrate, The content of polyethylene resin in the entire laminate is 80% by mass or more. packaging bag.

2. The packaging bag according to claim 1 , wherein the surface resin layer contains a resin material having a melting point of 150° C. or higher and 265° C. or lower.

3. 3. The packaging bag according to claim 1, wherein the difference in melting point between the polyethylene resin and the resin material contained in the surface resin layer and having a melting point of 150°C or higher is 20 to 80°C.

4. The packaging bag according to any one of claims 1 to 3, wherein the resin material of the surface resin layer is made of a polymer having a polar group.

5. The packaging bag according to any one of claims 1 to 4, wherein the resin material of the surface resin layer is one or more resin materials selected from ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyester, nylon 6, nylon 6,6, nylon 6-nylon 6,6 copolymer, MXD nylon, and amorphous nylon.

6. The packaging bag according to any one of claims 1 to 5, wherein the polyethylene resin layer contains a compatibilizer.

7. The packaging bag according to claim 6, wherein the surface resin layer is provided so as to be in contact with the polyethylene resin layer.

8. The packaging bag according to any one of claims 1 to 7, wherein the laminate further comprises a barrier coating layer on the vapor-deposited film.

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