Laminates and packaging containers

Abstract

To provide a laminate that can be suitably used as a laminate for manufacturing monomaterial packaging containers, can significantly improve interlayer adhesion with a vapor-deposited film, and can achieve desirable gas barrier properties. [Solution] The laminate of the present invention comprises at least a base material, an intermediate layer, and a sealant layer, wherein the intermediate layer comprises a polyethylene resin layer, a surface resin layer, and a vapor-deposited film provided on the surface resin layer, the base material and the sealant layer are both composed of polyethylene resin, the surface resin layer of the intermediate layer contains a resin material with a melting point of 150°C or higher, and the polyethylene resin layer and the surface resin layer of the intermediate layer are subjected to stretching treatment.

Description

[Technical Field]

[0001] This invention relates to laminates and packaging containers.

[0002] Conventionally, resin films made from polyester resins such as polyethylene terephthalate (hereinafter also referred to as polyester films) have been used in the manufacture of packaging containers 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 base material or intermediate layer, and are typically laminated with a polyethylene film, which is a sealant layer, to form a laminate, which is then molded into a packaging container.

[0004] As described above, packaging containers obtained by forming laminates by bonding different types of resin films, namely polyester film and polyethylene film, are difficult to separate into their respective layers. Therefore, packaging containers collected after use are not suitable for recycling and are not actively recycled.

[0005] In light of this situation, and with the aim of improving the recyclability of packaging containers, the production of packaging containers (monomaterial packaging containers) using a laminate made of the same material, by applying stretched polyethylene film (stretched polyethylene film) as the base material or intermediate layer instead of polyester film, is being considered. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2005-053223 [Overview of the project] [Problems that the invention aims to solve]

[0007] Now, in order to compensate for the deteriorated gas barrier property when changing the polyester film to a stretched polyethylene film, when the inventors tried to form a vapor deposition film on the surface of the stretched polyethylene film, they found a new problem that the adhesion between the stretched polyethylene film and the vapor deposition film was not sufficient, and a satisfactory gas barrier property could not be obtained.

[0008] And, surprisingly, the inventors provided a surface resin layer containing a resin material having a melting point of 150°C or higher on the surface of the stretched polyethylene film, whereby the adhesion of the vapor deposition film formed on the surface resin layer was improved. Along with this, they obtained the finding that the gas barrier property was significantly improved and the above problems could be solved.

[0009] The present invention has been made based on such findings, and the problem to be solved is to provide a laminate that can be suitably used as a laminate for producing a monomaterial packaging container, can significantly improve the adhesion between layers with a vapor deposition film, and can achieve a preferable gas barrier property.

[0010] Furthermore, the problem to be solved by the present invention is to provide a packaging container including the laminate.

Means for Solving the Problems

[0011] The laminate of the present invention includes at least a base material, an intermediate layer, and a sealant layer. [[ID=2,0]] The intermediate layer includes a polyethylene resin layer, a surface resin layer, and a vapor deposition film provided on the surface resin layer. Both the base material and the sealant layer are made of polyethylene resin. The surface resin layer of the intermediate layer contains a resin material having a melting point of 150°C or higher. The polyethylene resin layer and the surface resin layer of the intermediate layer are characterized by being subjected to a stretching treatment.

[0012] 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.

[0013] In one embodiment, the difference in melting points between the polyethylene resin of the base material and the resin material with a melting point of 150°C or higher contained in the surface resin layer is 20 to 80°C.

[0014] In one embodiment, the resin material of the surface resin layer is made of a polymer having polar groups.

[0015] 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.

[0016] In one embodiment, the polyethylene resin layer of the intermediate layer has a multilayer structure.

[0017] In one embodiment, the polyethylene resin layer of the intermediate layer comprises at least one layer containing a compatibilizer.

[0018] In one embodiment, the surface resin layer is provided so as to be in contact with the layer containing the compatibilizer for the polyethylene resin layer.

[0019] In one embodiment, the laminate of the present invention is further provided with a barrier coat layer on the vapor-deposited film.

[0020] In one embodiment, the laminate is used as a packaging container.

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

[0022] The packaging container of the present invention is characterized by being made of the above-mentioned laminate.

[0023] In one embodiment, the packaging container is a packaging bag. [Effects of the Invention]

[0024] According to the present invention, a laminate can be provided that can be suitably used as a laminate for manufacturing monomaterial packaging containers, significantly improves interlayer adhesion with a vapor-deposited film, and achieves desirable gas barrier properties. Furthermore, according to the present invention, a packaging container comprising the laminate can be provided. [Brief explanation of the drawing]

[0025] [Figure 1] This is a schematic cross-sectional view showing one embodiment of the laminate of the present invention. [Figure 2] This is a schematic cross-sectional view showing one embodiment of the laminate of the present invention. [Figure 3] This is a schematic cross-sectional view showing one embodiment of the laminate of the present invention. [Figure 4] This is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus. [Figure 5] This is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus. [Figure 6] This is a front view showing one embodiment of the packaging container of the present invention. [Figure 7] This is a perspective view showing one embodiment of the packaging container of the present invention. [Figure 8] This is a front view showing one embodiment of the packaging container of the present invention. [Figure 9] This is a cross-sectional view aa in Figure 8. [Modes for carrying out the invention]

[0026] (Laminated structure) As shown in Figure 1, the laminate 10 of the present invention comprises a base material 11, an intermediate layer 12, and a sealant layer 13, the intermediate layer 12 comprising a vapor-deposited film 14, a surface resin layer 15, and a polyethylene resin layer 16. 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 manufacturing monomaterial packaging containers. Furthermore, the intermediate layer of the laminate of the present invention has significantly improved interlayer adhesion between the polyethylene resin layer and the vapor-deposited film, and possesses extremely high gas barrier properties.

[0027] The polyethylene resin content relative to the total amount of solids in the laminate is preferably 80% by mass or more, and more preferably 90% by mass or more. This makes it possible to create a laminate that can be suitably used in the manufacture of monomaterial packaging containers.

[0028] Although Figure 1 shows a configuration in which the vapor-deposited film 14 and the substrate 11 are adjacent, the configuration is not limited to this, and as shown in Figure 2, the vapor-deposited film 14 may be adjacent to the sealant layer 13. From the viewpoint of the heat-sealability of the packaging container made by the barrier laminate 10 of the present invention, it is preferable that the vapor-deposited film 14 is provided adjacent to the substrate 11, as shown in Figure 1.

[0029] Furthermore, in one embodiment, the intermediate layer 12 may further include an adhesive resin layer 17 between the surface resin layer 15 and the polyethylene resin layer 16, as shown in Figure 3.

[0030] Furthermore, in one embodiment, the laminate 10 of the present invention includes a barrier coat layer adjacent to the vapor-deposited film 14 (not shown).

[0031] Furthermore, in one embodiment, the laminate 10 of the present invention includes an adhesive layer (not shown) between any layers, for example, between the substrate 11 and the intermediate layer 12, or between the intermediate layer 12 and the sealant layer 13.

[0032] The following describes each layer of the laminate of the present invention.

[0033] (base material) The base material is made of the same resin as the intermediate polyethylene resin layer and the sealant layer, i.e., polyethylene resin. A laminate having such a configuration can be suitably used as a laminate for manufacturing monomaterial packaging containers. As polyethylene resins, 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 polyethylene resin, biomass-derived polyethylene resin or mechanically or chemically recycled polyethylene resin can also be used.

[0034] Here, the high-density polyethylene resin has a density of 0.945 g / cm³. 3 The above polyethylene resins can be used, and as a medium-density polyethylene resin, the density is 0.925 g / cm³. 3 More than 0.945g / cm 3 A polyethylene resin with a density of less than 0.900 g / cm³ can be used, and as a low-density polyethylene resin, a density of 0.900 g / cm³ can be used. 3 More than 0.925g / cm 3 A polyethylene resin with a density of less than 0.900 g / cm³ can be used, and as a linear low-density polyethylene resin, a density of 0.900 g / cm³ can be used. 3 More than 0.925g / cm 3 Polyethylene resins with a density of less than 0.900 g / cm³ can be used, and ultra-low density polyethylene resins have a density of 0.900 g / cm³. 3 A polyethylene resin of less than [amount missing] can be used.

[0035] The content of the polyethylene resin in the base material is preferably 80% by mass or more, and more preferably 90% by mass or more. Thereby, it can be made into a laminate that can be suitably used for producing a monomaterial packaging container.

[0036] Within a range that does not impair the characteristics of the present invention, the base material may contain a resin material other than the polyethylene resin. For example, polyolefin resins such as polypropylene resin, (meth)acrylic resins, vinyl resins, cellulose resins, polyamide resins, polyester resins, and ionomer resins can be mentioned. From the viewpoint of its recyclability, it is particularly preferable that the base material does not contain resins other than the polyethylene resin.

[0037] Within a range that does not impair the characteristics of the present invention, the base material can contain the above-mentioned additives.

[0038] The base material may have a single-layer structure or a multilayer structure.

[0039] In a base material having a multilayer structure, the densities of the polyethylene resins constituting each layer may be different, that is, a density gradient may be provided in the base material. By providing a density gradient in the base material, its strength, heat resistance, and stretching suitability are significantly improved.

[0040] In a base material provided with a density gradient, when the density difference between each layer is large, there is a risk of delamination occurring at the interface. Therefore, the density difference between each layer is preferably 0.04 g / cm 3 or less, and more preferably 0.02 g / cm 3 [[ID=​​​​​​​In one embodiment, the substrate having a density gradient consists of three layers: a layer containing high-density polyethylene resin, a layer containing medium-density polyethylene resin, and a layer containing high-density polyethylene resin. By creating a three-layer structure with the density gradient described above, the strength, heat resistance, and stretchability of the base material are significantly improved. Furthermore, curling of the base material can be effectively prevented.

[0043] In one embodiment, the substrate having a density gradient consists 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 constructing the base material with a five-layer structure that provides the density gradient described above, the strength, heat resistance, and stretchability are significantly improved. Furthermore, curling of the base material can be effectively prevented. Substrates with this configuration can be reliably fabricated by the following inflation method. 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, layers containing at least one of low-density polyethylene resin and linear low-density polyethylene resin can be pressed together using a rubber roll or the like. By manufacturing in this manner, the number of defective products in production can be significantly reduced, ultimately improving production efficiency.

[0044] In one embodiment, the substrate having a density gradient consists of seven layers: a layer containing high-density polyethylene resin, a layer containing a blend of high-density polyethylene resin and medium-density polyethylene resin, a layer containing at least one of low-density polyethylene resin and linear low-density polyethylene resin, a layer containing a blend of high-density polyethylene resin and medium-density polyethylene resin, and a layer containing high-density polyethylene resin. By constructing the base material with a five-layer structure having the density gradient described above, the strength, heat resistance, and stretchability are significantly improved. Furthermore, curling of the base material can be effectively prevented. In addition, delamination of the base material can be effectively prevented. Furthermore, substrates with this configuration can be stably fabricated by the inflation method described above.

[0045] In one embodiment, the substrate is subjected to a stretching treatment, which may be uniaxial stretching or biaxial stretching. The stretching ratio of the substrate in the longitudinal direction (MD direction) and transverse direction (TD direction) is preferably 2 times or more and 15 times or less, and preferably 5 times or more and 13 times or less. By increasing the stretching ratio to 2 times or more, the strength and heat resistance of the substrate can be further improved. Furthermore, the printability of the substrate can be improved. Furthermore, from the viewpoint of the breaking limit of the substrate, it is preferable that the stretch ratio is 15 times or less.

[0046] The substrate may have a printed layer on its surface, and the image formed on the printed layer is not particularly limited and may represent characters, patterns, symbols, or combinations thereof. The printing layer can be formed using biomass-derived ink, thereby reducing the environmental impact. The method for forming the printed layer is not particularly limited, and examples include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing.

[0047] Furthermore, it is preferable that the substrate is surface-treated. This improves adhesion with adjacent layers. The surface treatment method is not particularly limited and includes physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals. Alternatively, an anchor coat layer may be formed on the substrate surface using a conventionally known anchor coat agent.

[0048] 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 keeping the thickness of the substrate within the above numerical range, the printability, strength, and heat resistance of the substrate can be further improved.

[0049] (Middle class) The intermediate layer comprises 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 vapor-deposited film forming surface faces the substrate side or the sealant layer side. However, from the viewpoint of the heat-sealability of the packaging container made using the barrier laminate of the present invention, it is preferable that the intermediate layer be provided so that the vapor-deposited film forming surface faces the substrate side.

[0050] The ratio of the thickness of the surface resin layer to the total thickness of the intermediate layer is preferably 2% to 20%, and more preferably 4% to 15%. By setting the ratio of the surface resin layer thickness to the total thickness of the intermediate layer to 2% or more, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties can be further enhanced. Furthermore, by setting the ratio of the surface resin layer thickness to the total thickness of the intermediate layer to 20% or less, a laminate suitable for use in the manufacture of monomaterial packaging containers can be created. In addition, the film-forming properties and processability of the intermediate layer can be further improved.

[0051] (Polyethylene resin layer) The polyethylene resin layer is made of polyethylene resin. As polyethylene resins, 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 polyethylene resin, biomass-derived polyethylene resin or mechanically or chemically recycled polyethylene resin can also be used.

[0052] The polyethylene resin content in the polyethylene resin layer is preferably 70% by mass or more, and more preferably 80% by mass or more. This allows for the more suitable use of the laminate in the production of monomaterial packaging containers.

[0053] 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 packaging containers made using the laminate are heated, melted, and recycled, the resin material in the surface resin layer with a melting point of 150°C or higher and the polyethylene resin in the polyethylene resin layer can be uniformly mixed, effectively preventing a decrease in their physical properties. Furthermore, a decrease in transparency can be effectively prevented. Furthermore, when the polyethylene resin layer has a multilayer structure, it is preferable that the compatibilizer be included in the layer in contact with the surface resin layer of the polyethylene resin layer. By including the compatibilizer in the layer in contact with the surface resin layer of the polyethylene resin layer, the above effects can be further improved.

[0054] While conventionally known compatibilizers can be appropriately selected and used, from the viewpoint of recyclability, unsaturated carboxylic acid-modified polyolefin resins are preferred, and among them, maleic anhydride-modified polyethylene resins are more preferred.

[0055] The content of the compatibilizer in the layer containing the compatibilizer is preferably 5% by mass or more and 30% by mass or less. The above effect can be further improved by increasing the compatibilizer content in the polyethylene resin layer to 5% by mass or more. By limiting the compatibilizer content in the polyethylene resin layer to 30% by mass or less, the strength and heat resistance of the substrate can be improved.

[0056] Within the limits that do not impair the properties of the present invention, the polyethylene resin layer may contain resin materials other than polyethylene resin, such as polyolefin resins such as polypropylene resin, (meth)acrylic resins, vinyl resins, cellulose resins, polyamide resins, polyester resins, and ionomer resins. Furthermore, from the standpoint of its recyclability, it is particularly preferable that the polyethylene resin layer does not contain any resins other than polyethylene resin.

[0057] Furthermore, within the limits that do not impair the properties of the present invention, the polyethylene resin layer may contain additives, such as crosslinking agents, antioxidants, antiblocking agents, lubricants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0058] The polyethylene resin layer may have a single-layer structure or a multi-layer structure.

[0059] In a polyethylene resin layer having a multilayer structure, the densities of the polyethylene resins constituting each layer may differ; that is, a density gradient may be provided in the polyethylene resin layer. By creating a density gradient in the polyethylene resin layer, its strength, heat resistance, and stretchability are significantly improved.

[0060] In polyethylene resin layers with a density gradient, if the density difference between each layer is large, delamination may occur at the interface. Therefore, the density difference between each layer should be 0.04 g / cm³. 3 Preferably, it is 0.02 g / cm³. 3 The following is even more preferable:

[0061] The following are examples of embodiments of polyethylene resin layers with density gradients. However, the composition of the polyethylene resin layer is not limited to these examples.

[0062] In one embodiment, the polyethylene resin layer with a density gradient consists of three layers: a layer containing high-density polyethylene resin, a layer containing medium-density polyethylene resin, and a layer containing high-density polyethylene resin. By creating a three-layer polyethylene resin structure with the density gradient described above, the strength, heat resistance, and stretchability are significantly improved. Furthermore, curling in the intermediate layer can be effectively prevented.

[0063] In one embodiment, the polyethylene resin layer with a density gradient consists 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 constructing the polyethylene resin layer with a five-layer structure that has the density gradient described above, the strength, heat resistance, and stretchability are significantly improved. Furthermore, curling in the intermediate layer can be effectively prevented. A polyethylene resin layer with this configuration can be reliably fabricated by the inflation method described above.

[0064] In one embodiment, the polyethylene resin layer with a density gradient consists of seven layers: a layer containing high-density polyethylene resin, a layer containing a blend of high-density polyethylene resin and medium-density polyethylene resin, a layer containing at least one of low-density polyethylene resin and linear low-density polyethylene resin, a layer containing a blend of high-density polyethylene resin and medium-density polyethylene resin, and a layer containing high-density polyethylene resin. By constructing the polyethylene resin layer with a five-layer structure that has the density gradient described above, the strength, heat resistance, and stretchability are significantly improved. Furthermore, curling in the intermediate layer can be effectively prevented. In addition, delamination in the intermediate layer can be effectively prevented. Furthermore, polyethylene resin layers with this configuration can be stably produced by the inflation method described above.

[0065] 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 increasing the thickness of the polyethylene resin layer to 10 μm or more, the strength and heat resistance of the intermediate layer 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 intermediate layer can be further improved.

[0066] 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 represent letters, patterns, symbols, or combinations thereof. The printing layer can be formed using biomass-derived ink, thereby reducing the environmental impact. The method for forming the printed layer is not particularly limited, and examples include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing.

[0067] (Surface resin layer) The intermediate layer of the laminate comprises a surface resin layer on top of a polyethylene resin layer, which contains a resin material with a melting point of 150°C or higher (hereinafter referred to as a high-melting-point resin material).

[0068] 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 enhanced. Furthermore, when a sealant layer is laminated, the adhesion with the sealant layer can be improved, and the laminate strength of the packaging container made from this laminate can be further enhanced.

[0069] The melting point of the high-melting-point resin material is preferably 265°C or lower, more preferably 260°C or lower, and even more preferably 250°C or lower. By setting the melting point of the high-melting-point resin material to 265°C or lower, the film-forming properties of the intermediate layer can be improved.

[0070] 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, and more preferably 20 to 60°C. By ensuring that the difference between the melting point of the high-melting-point resin material in the surface resin layer and the melting point of the polyethylene 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 enhanced. Furthermore, when a sealant layer is laminated, the adhesion with the sealant layer can be improved, and the laminate strength of the packaging container made from this laminate can be further enhanced. Furthermore, by ensuring that 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 80°C or less, the film-forming properties of the intermediate layer can be further improved.

[0071] In one embodiment, the high-melting-point resin material is composed of a polymer having polar groups. By making the high-melting-point resin material a polymer having polar groups, the adhesion to the vapor-deposited film can be further improved.

[0072] In the present invention, a polar group refers to a group containing one or more heteroatoms, and examples include ester groups, epoxy groups, hydroxyl groups, amino groups, amide groups, carboxyl groups, carbonyl groups, carboxylic acid anhydride groups, sulfone groups, thiol groups, and halogen groups. Among these, from the viewpoint of the lamination strength of the packaging container, hydroxyl groups, ester groups, amino groups, amide groups, carboxyl groups, and carbonyl groups are preferred, with hydroxyl groups being more preferred.

[0073] Examples of high-melting-point resin materials include vinyl resins, polyamides, polyimides, polyesters, (meth)acrylic resins, cellulose resins, polyolefin resins, and ionomer resins.

[0074] In the present invention, resin materials having a melting point of 150°C or higher and having polar groups 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 resin materials, 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 enhanced.

[0075] 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 setting the content of the high-melting-point resin material in the surface resin layer to 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 intermediate layer on which the vapor-deposited film is formed can be effectively improved.

[0076] Within the limits that do not impair the properties of the present invention, the surface resin layer may contain resin materials other than high-melting-point resin materials. Furthermore, from the viewpoint of adhesion to the vapor-deposited film, it is preferable that the surface resin layer does not contain resin materials other than high-melting-point resin materials.

[0077] Furthermore, within the limits that do not impair the properties of the present invention, the surface resin layer may contain additives, such as crosslinking agents, antioxidants, antiblocking agents, lubricants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0078] 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 surface resin layer thickness 0.1 μm or more, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties of the intermediate layer on which the vapor-deposited film is formed can be further improved. In addition, when a sealant layer is laminated, the adhesion with the sealant layer can be improved, and the laminate strength of the packaging container made from this laminate can be further improved. Furthermore, by setting the thickness of the surface resin layer to 5 μm or less, an intermediate layer suitable for use in the manufacture of monomaterial packaging containers can be created. In addition, the film-forming properties and processability of the intermediate layer can be further improved.

[0079] Furthermore, the surface resin layer may be surface-treated. This can improve adhesion with adjacent layers. The surface treatment method is not particularly limited and includes physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0080] (adhesive resin layer) In one embodiment, the intermediate layer may include an adhesive resin layer between the polyethylene resin layer and the surface resin layer, thereby improving the adhesion between these layers.

[0081] The adhesive resin layer can be formed by using adhesive resins such as polyether, polyester, silicone resin, epoxy resin, polyurethane, vinyl resin, phenolic resin, and polyolefin. Among the above, polyolefins and their acid-modified products are preferred because they allow the laminate to be configured in a way that is more suitable for monomaterial packaging containers, and polyethylene and its acid-modified products are particularly preferred. Commercially available adhesive polyethylene can be used; for example, the Admer series manufactured by Mitsui Chemicals, Inc. can be used.

[0082] In one embodiment, the surface resin layer, polyethylene resin layer, and adhesive resin layer of the intermediate layer are subjected to stretching treatment, which may be uniaxial stretching or biaxial stretching. The stretching ratio in the longitudinal direction (MD direction) and transverse direction (TD direction) is preferably 2 times or more and 15 times or less, and preferably 5 times or more and 13 times or less. By increasing the stretching ratio to 2 times or more, the strength and heat resistance of the intermediate layer can be further improved. Furthermore, the printability of the intermediate layer can be improved. Furthermore, from the standpoint of the fracture limit, it is preferable that the elongation ratio is 15 times or less.

[0083] In one embodiment, the surface resin layer and polyethylene resin layer comprising the intermediate layer are co-extruded films, which can be manufactured by forming a film using a T-die method or an inflation method, and then stretching the resulting resin film. By forming the film using the inflation method, the stretching of the resin film can be performed simultaneously.

[0084] (Vaporized film) The intermediate layer of the laminate of the present invention comprises a vapor-deposited film on the surface resin layer. In the laminate, the vapor-deposited film and the surface resin layer have high adhesion and extremely high gas barrier properties, specifically oxygen barrier properties and water vapor barrier properties. Furthermore, because the laminate has a vapor-deposited film, packaging containers made using the laminate can suppress the mass reduction of the contents filled inside.

[0085] The vapor-deposited film can be made 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), and yttrium (Y). The vapor-deposited film can consist of two or more layers, and may be made of the same material or different materials. Among the above, from the viewpoint of adhesion to the surface resin layer and gas barrier properties, the vapor-deposited film is preferably composed of aluminum, aluminum oxide (alumina), or silicon oxide (silica).

[0086] It is preferable that the surface of the deposited film is subjected to the above-mentioned surface treatment. This improves adhesion with adjacent layers.

[0087] Furthermore, the thickness of the deposited film is preferably 1 nm to 150 nm, more preferably 5 nm to 60 nm, and even more preferably 10 nm to 40 nm. By increasing the thickness of the deposited film to 1 nm or more, the oxygen barrier and water vapor barrier properties of the laminate can be further improved. Furthermore, by setting the thickness of the vapor-deposited film to 150 nm or less, a laminate suitable for use in the production of monomaterial packaging containers can be created. In addition, the occurrence of cracks in the vapor-deposited film can be prevented.

[0088] A vacuum deposition apparatus with plasma assistance can be used as the equipment for forming vapor-deposited films by the PVD method. One embodiment of a method for depositing a vapor-deposited film using a vacuum deposition apparatus with plasma assistance is described below. In one embodiment, the vacuum film deposition apparatus, as shown in Figures 4 and 5, comprises a vacuum container A, a laminate 10 of a surface resin layer and a polyethylene resin layer, an unwinding section B, a film deposition drum C, a winding section D, a transport roll E, an evaporation source F, a reaction gas supply section G, an anti-deposition box H, a deposition material I, and a plasma gun J. Figure 4 is a schematic cross-sectional view of the vacuum deposition apparatus in the XZ plane, and Figure 5 is a schematic cross-sectional view of the vacuum deposition apparatus in the XY plane. As shown in Figure 4, the laminate 10 wound onto the film-forming drum C is positioned at the top of the vacuum vessel A with its surface resin layer facing downwards, and an electrically grounded protective box H is positioned below the film-forming drum C inside the vacuum vessel A. An evaporation source F is positioned on the bottom of the protective box H. The film-forming drum C is positioned inside the vacuum vessel A such that the surface resin layer of the laminate 10 wound onto the film-forming drum C is positioned opposite the top surface of the evaporation source F at a certain distance. Furthermore, a transport roll E is positioned 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 deposition material I and is equipped with a heating device (not shown). The reaction gas supply unit G is the part that supplies reaction gases (such as oxygen, nitrogen, helium, argon, and mixtures thereof) that react with the evaporated deposition material. The vapor-deposited material I, heated and evaporated from the evaporation source F, is irradiated onto the surface resin layer of the laminate 10. Simultaneously, plasma is also irradiated onto the surface resin layer from the plasma gun J, and a vapor-deposited film is formed. Details of this formation method are disclosed in Japanese Patent Publication No. 2011-214089.

[0089] Plasma generators used in plasma chemical vapor deposition (PVM) can include high-frequency plasma, pulsed-wave plasma, and microwave plasma generators. Alternatively, a device with two or more deposition chambers may be used. Preferably, the device is equipped with a vacuum pump and capable of maintaining a vacuum in each deposition chamber. The vacuum level in each deposition chamber is 1 × 10 to 1 × 10 -6 Pa is preferable. One embodiment of a method for depositing a vapor-deposited film using a plasma generator is described below. First, the laminate of the surface resin layer and the polyethylene resin layer is sent to the deposition chamber and transported onto the cooling / electrode drum at a predetermined speed via auxiliary rolls. Next, a mixed gas composition containing a monomer gas for film formation containing inorganic oxides, oxygen gas, and an inert gas is supplied from the gas supply device into the film deposition chamber. Plasma is generated on the surface resin layer by glow discharge and irradiated to form a vapor-deposited film containing inorganic oxides on the surface resin layer. Details of this formation method are disclosed in Japanese Patent Publication No. 2012-076292.

[0090] A continuous vapor deposition apparatus equipped with a plasma pretreatment chamber and a deposition chamber can be used as the apparatus for forming vapor-deposited films. One embodiment of a method for forming a vapor-deposited film using the apparatus is described below. First, in the plasma pretreatment chamber, plasma is irradiated from a plasma supply nozzle onto the surface resin layer of a laminate comprising a surface resin layer and a polyethylene resin layer. Next, in the film deposition chamber, a vapor-deposited film is deposited on the plasma-treated surface resin layer. Details of this formation method are disclosed in the international publication WO2019 / 087960.

[0091] (Barrier coat layer) The laminate can further include a barrier coating layer on the vapor-deposited film. This improves the oxygen barrier and water vapor barrier properties of the laminate.

[0092] In one embodiment, the barrier coat layer includes polyamide resins such as ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, nylon 6, nylon 6,6 and polymethoxylylene adipamide (MXD6), polyester resins, polyurethane resins, and gas barrier resins such as (meth)acrylic resins.

[0093] The gas barrier resin content 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 setting the gas barrier resin content in the barrier coat layer to 50% by mass or more, the oxygen barrier properties and water vapor barrier properties can be further improved.

[0094] 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 barrier coat layer thickness 0.01 μm or more, the oxygen barrier and water vapor barrier properties of the laminate can be further improved. By making the barrier coat layer thickness 10 μm or less, the processability of the laminate can be improved. In addition, the recyclability of packaging containers made using a laminate of a substrate and a sealant layer made of polyethylene resin can be improved.

[0095] A barrier coating layer can be formed by dissolving or dispersing the above-mentioned material in water or a suitable solvent, applying it, and drying it. Alternatively, a barrier coating layer can also be formed by applying and drying a commercially available barrier coating agent.

[0096] In another embodiment, the barrier coating layer is a gas barrier coating film containing at least one resin composition, such as a hydrolyzed metal alkoxide or a hydrolyzed condensate of a metal alkoxide, obtained by polycondensation of 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, and an organic solvent. By providing such a barrier coating layer on the vapor-deposited film, the occurrence of cracks in the vapor-deposited film can be effectively prevented.

[0097] In one embodiment, the metal alkoxide is represented by the following general formula. R 1 n M(OR 2 ) m (However, in the formula, R 1 , R 2 (Each represents an organic group with 1 to 8 carbon atoms, M represents a metal atom, n represents a non-negative integer, m represents a non-negative integer, and n+m represents the valence of M.)

[0098] Examples of metal atoms M that can be used include silicon, zirconium, titanium, and aluminum. Also, R 1 and R 2 Examples of organic groups represented by include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, and i-butyl groups.

[0099] 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).

[0100] Furthermore, it is preferable to use a silane coupling agent together with the above-mentioned metal alkoxide. As the silane coupling agent, known organoalkoxysilanes containing organic reactive groups can be used.

[0101] As water-soluble polymers, polyvinyl alcohol and ethylene-vinyl alcohol copolymers are preferred, and from the viewpoint of oxygen barrier properties, water vapor barrier properties, water resistance and weather resistance, it is preferable to use these in combination.

[0102] 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 setting the thickness of the gas barrier coating film to 0.01 μm or more, the oxygen barrier and water vapor barrier properties of the laminate can be improved. Furthermore, crack formation in the vapor-deposited film can be prevented. By setting the thickness of the gas barrier coating film to 10 μm or less, a laminate can be made that is suitable for use in the manufacture of monomaterial packaging containers.

[0103] A gas barrier coating film can be formed by applying a composition containing the above-mentioned materials using conventionally known methods such as roll coating (including gravure roll coaters), spray coating, spin coating, dipping, brushing, barcode application, or applicator application, and then polycondensing the composition by a sol-gel method. Acid or amine compounds are preferred as catalysts for the sol-gel process.

[0104] The above composition may further contain an acid. The acid is used as a catalyst for the sol-gel process, mainly as a catalyst for the hydrolysis of alkoxides and silane coupling agents. As acids, mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid, as well as organic acids such as acetic acid and tartaric acid, are used.

[0105] Furthermore, the above composition may contain an organic solvent. Examples of organic solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butanol.

[0106] The following describes one embodiment of a method for forming a gas barrier coating film. First, a composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and, if necessary, a silane coupling agent. A polycondensation reaction gradually proceeds within this composition. Next, the composition is applied to the vapor-deposited film and dried using the conventionally known method described above. This drying further promotes the polycondensation reaction between the alkoxide and the water-soluble polymer (and the silane coupling agent if the composition contains one), forming a layer of composite polymer. Finally, by heating, a gas barrier coating can be formed.

[0107] (Sealant layer) In one embodiment, the sealant layer is composed of a substrate and the same resin as the intermediate polyethylene resin layer, i.e., polyethylene resin. A laminate having such a configuration can be suitably used as a laminate for manufacturing monomaterial packaging containers. As polyethylene resins, 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 polyethylene resin, biomass-derived polyethylene resin or mechanically or chemically recycled polyethylene resin can also be used.

[0108] The polyethylene resin content in the sealant layer is preferably 80% by mass or more, and more preferably 90% by mass or more. This makes it possible to create a laminate that can be suitably used in the manufacture of monomaterial packaging containers.

[0109] Within the limits that do not impair the properties of the present invention, the sealant layer may contain resin materials other than polyethylene resin, such as polyolefin resins such as polypropylene resin, (meth)acrylic resins, vinyl resins, cellulose resins, polyamide resins, polyester resins, and ionomer resins. Furthermore, from the standpoint of its recyclability, it is particularly preferable that the sealant layer does not contain any resins other than polyethylene resin.

[0110] The sealant layer may contain the above-mentioned additives, to the extent that it does not impair the properties of the present invention.

[0111] The sealant layer may have a single-layer structure or a multi-layer structure.

[0112] The thickness of the sealant layer is preferably 20 μm to 100 μm, and more preferably 30 μm to 70 μm. By increasing the thickness of the sealant layer to 20 μm or more, the lamination strength of the packaging container can be further improved. Furthermore, by making the sealant layer thickness 100 μm or less, the moldability of the laminate can be improved, making it easier to manufacture packaging containers.

[0113] The sealant layer can be formed by laminating a resin film made of the above-mentioned resin material, such as polyethylene resin, with a vapor-deposited film or barrier coat layer provided on a surface vapor-deposited film, via a conventionally known adhesive or the like. Furthermore, the sealant layer can be formed by melt-extruding the above-mentioned resin material onto a vapor-deposited film provided on a surface vapor-deposited film, or onto a barrier coat layer. Furthermore, when the laminate is used to manufacture laminate tubes or the like, the laminate further comprises a sealant layer on the non-deposited surface of the substrate (not shown).

[0114] (Adhesive layer) The laminate of the present invention may include an adhesive layer between any of the layers, for example, between the substrate and the intermediate layer, or between the intermediate layer and the sealant layer. The adhesive layer contains at least one type of adhesive, which may be a one-component curing type, a two-component curing type, or a non-curing type. The adhesive may be a solvent-free type or a solvent-based type, but from the viewpoint of environmental impact, a solvent-free type adhesive is preferably used. Examples of solvent-free adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives, and urethane-based adhesives. Among these, two-component curing type urethane-based adhesives are 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.

[0115] The thickness of the adhesive layer is preferably 1 μm to 15 μm, and more preferably 3 μm to 10 μm. By making the thickness of the adhesive layer 1 μm or more, the adhesion between layers can be improved. Furthermore, by making the thickness of the adhesive layer 15 μm or less, the recyclability of the packaging container made using the barrier laminate of the present invention, which comprises a base material made of polyethylene and a sealant layer, can be improved.

[0116] (packaging container) The packaging container of the present invention is characterized by comprising the above-mentioned laminate. Examples of packaging containers include packaging bags, lids, and laminate tubes.

[0117] Examples of packaging bags include various types such as standing pouch type, side seal type, two-side seal type, three-side seal type, four-side seal type, envelope seal type, gusset seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type.

[0118] As shown in Figure 6, the packaging container of the present invention is a packaging bag 20 made by bonding two laminated materials together (the shaded area is the heat-sealed portion).

[0119] A packaging bag in the form shown in Figure 6 can be manufactured by preparing two laminates, each comprising a base material and a vapor-deposited film and sealant layer provided on one side of the base material, overlapping these laminates so that the sealant layers face each other, and heat-sealing three sides.

[0120] In one embodiment, the packaging container of the present invention is a standing pouch type packaging bag 30 (hereinafter simply referred to as a standing pouch 30), as shown in Figure 7, and the standing pouch 30 comprises a body (side sheet) and a bottom (bottom sheet). The body (side sheet) of the standing pouch 30 consists of a laminate comprising at least a base material, and a vapor-deposited film and a sealant layer provided on one side of the base material. Furthermore, the bottom portion may also consist of a laminate comprising a base material and a vapor-deposited film and sealant layer provided on one side of the base material. By adopting such a configuration, the gas barrier properties of the standing pouch 30 can be further improved.

[0121] As shown in Figure 7, the body (side sheet) of the standing pouch 30 can be formed by manufacturing a bag such that the sealant layer of a laminate comprising a base material and a vapor-deposited film and sealant layer provided on one side of the base material becomes the innermost layer. In another embodiment, two laminates are prepared, each comprising a base material and a vapor-deposited film and sealant layer provided on one side of the base material. These are then stacked so that the sealant layers face each other. Two V-shaped folded laminates are inserted from both ends of the stacked laminates, with the sealant layers facing outwards, and heat-sealed to form the body (side sheet) of the standing pouch 30. This manufacturing method allows for the creation of a stand pouch having a body with side gussets. Furthermore, the bottom (bottom sheet) of the standing pouch 30 can be formed by inserting a laminate between the formed body (side sheets) and heat sealing it. More specifically, the laminate can be formed by folding it in a V-shape so that the sealant layer faces outwards, inserting it between the formed side sheets, and heat sealing it.

[0122] Furthermore, the packaging container may be equipped with an easy-opening mechanism 41, as shown in Figure 6. Examples of the easy-opening means 41 include a notch portion 42 that serves as the starting point for tearing, as shown in Figure 6, and a half-cut line 43 formed by laser processing or a cutter, which serves as the path for tearing.

[0123] Furthermore, the packaging container may be a stand-up pouch equipped with a dispensing nozzle 51, as shown in Figure 7. Furthermore, from the viewpoint of ease of opening, the stand pouch 30 may be provided with a curved portion 52 that curves inward, as shown in Figure 7. Furthermore, it may include a cut portion 53 formed by a laser beam or the like.

[0124] (Laminated tube) The laminate tube of the present invention is characterized by comprising the above-mentioned laminate, specifically a laminate composed of a laminated film having sealant layers on both sides. The laminate tube of the present invention will be described below with reference to the drawings. Figure 8 is a simplified diagram showing the structure of the laminate tube 60, and Figure 9 is a cross-sectional view of aa in Figure 8. As shown in Figure 9, the laminate tube 60 comprises a laminate tube body 61 having a head portion 62 and a body portion 63, and the body portion 63 is characterized in that it is made of the above-mentioned laminate.

[0125] (head) The head portion 62 includes a shoulder portion 64 connected to one end of the torso portion 63 and an extraction port portion 65 connected to the shoulder portion 64. In one embodiment, the spout portion 65 is provided with threads 67 for screwing on the cap 66.

[0126] In one embodiment, the head is made of a resin composition containing polyethylene, which improves the recyclability of the tube container.

[0127] The method for manufacturing the head is not particularly limited and can be manufactured by conventionally known methods. For example, the head can be manufactured by compression molding or injection molding and then joined to the body.

[0128] (torso) In the laminate tube body 61 of the present invention, the torso portion 63 is connected to the shoulder portion 64 of the head portion 62. The body portion 63 includes a welded portion 68 formed by rolling the laminated material into a cylindrical shape, overlapping the heat-sealed layers, and heat-sealing the overlapped portion. Furthermore, the body portion 63 includes a bottom seal portion 69 formed by heat-sealing the opening of the rolled laminate.

[0129] (cap) The laminated tube 60 may be equipped with a screw-type or plug-type cap 66. The cap is detachably attached to the dispensing opening at the top of the dispenser and serves to close the dispensing opening. The cap is made of a resin composition containing a thermoplastic resin. From the standpoint of recyclability, polyethylene resin is particularly preferred among thermoplastic resins.

[0130] The contents filled into the packaging container are not particularly limited and may be liquids, powders, or gels. They may also be food products or non-food products. [Examples]

[0131] 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.

[0132] Example 1-1 Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3 A single-layer extruded film was produced using the inflation method with a melting point of 129°C, and then stretched five times in the longitudinal direction (MD direction) using a stretching device to produce a substrate with a thickness of 25 μm.

[0133] Ethylene vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., EVAL E171B, melting point: 165℃, density: 1.14 g / cm³) 3 )and, Adhesive resin (manufactured by Mitsui Chemicals, Inc., maleic anhydride-modified polyethylene, Admer NF557), Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3 (melting point: 129°C) After co-extruding the material using the inflation molding method, an intermediate layer was fabricated by stretching it five times in the longitudinal direction (MD direction) using a stretching device. In the intermediate layer obtained in this manner, 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, and the thickness of the polyethylene resin layer composed of medium-density polyethylene was 20 μm.

[0134] On the surface of the intermediate layer's surface resin layer, a PVD (Physical Vapor Deposition) method was applied, at a pressure of 3.0 × 10⁻⁶. -2 A 30 nm thick aluminum vapor-deposited film was formed using Pa.

[0135] The substrate and the vapor-deposited film-forming surface of the intermediate layer were laminated together using a two-component curing urethane adhesive (Rock Paint Co., Ltd., Ru-77T / H-7).

[0136] First linear low-density polyethylene (Prime Polymer Co., Ltd., SP2520, density: 0.925 g / cm³) 3Multilayer extrusion was performed using inflation molding to produce unstretched polyethylene films of 20 μm thickness each of the first linear low-density polyethylene (melting point: 122°C) and a second linear low-density polyethylene (SP1520, manufactured by Prime Polymer Co., Ltd., density 0.913, melting point 116°C). The first linear low-density polyethylene side of this unstretched polyethylene film was laminated to the non-deposited surface of the intermediate layer via a two-component curing urethane adhesive (Rock Paint Co., Ltd., Ru-77T / H-7) to obtain the laminate of the present invention. The polyethylene content in the laminates is summarized in Table 1. The laminates obtained in subsequent examples and comparative examples, as well as the polyethylene content in those laminates, are also summarized in Table 1.

[0137] Examples 1-2 High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm³) 3 (melting point: 135℃) Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3 (melting point: 129°C) High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm³) 3 (melting point: 135℃) After co-extruding the material using the inflation molding method, the substrate was prepared by stretching it five times in the longitudinal direction (MD direction) using a stretching device. In the substrate obtained in this manner, the thickness of the layer made of high-density polyethylene was 5 μm, the thickness of the layer made of medium-density polyethylene was 15 μm, and the thickness of the layer made of high-density polyethylene was 5 μm.

[0138] A laminate was fabricated in the same manner as in Example 1-1, except that the base material was changed to a three-layer structure base material prepared as described above.

[0139] Examples 1-3 High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm³) 3 (melting point: 135℃) High-density polyethylene (ExxonMobil, HTA108, density: 0.961 g / cm³) 3 (Melting point: 135°C) and medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3 A blended resin containing a melting point of 129°C in a ratio of 4:6 by mass, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3 (melting point: 129°C) Ultra-low density polyethylene (Dow Chemical, Affinity EG8100G, density: 0.870 g / cm³) 3 (melting point: 55℃), The material was extruded using an inflation molding method to form a tubular film comprising, from the outside in, a layer made of high-density polyethylene, a layer made of blended resin, a layer made of medium-density polyethylene, and a layer made of ultra-low-density polyethylene. The inner ultra-low-density polyethylene layers were then pressed together using rubber rolls. The film obtained in this manner comprises a layer made of high-density polyethylene, a layer made of a blended resin, a layer made of medium-density polyethylene, a layer made of ultra-low-density polyethylene, a layer made of medium-density polyethylene, a layer made of a blended resin, and a layer made of high-density polyethylene.

[0140] The film obtained as described above was stretched five times in the longitudinal direction (MD direction) using a stretching device to produce a substrate. In the film obtained in this manner, the thickness of the layer made of high-density polyethylene was 2.5 μm, the thickness of the layer made of blended resin was 2.5 μm, the thickness of the layer made of medium-density polyethylene was 6.25 μm, the thickness of the layer made of ultra-low-density polyethylene was 2.5 μm, the thickness of the layer made of medium-density polyethylene was 6.25 μm, the thickness of the layer made of blended resin was 2.5 μm, and the thickness of the layer made of high-density polyethylene was 2.5 μm.

[0141] A laminate was fabricated in the same manner as in Example 1-1, except that the base material was changed to a 7-layer structure base material prepared as described above.

[0142] Examples 1-4 Ethylene vinyl alcohol copolymer is used with polyamide (manufactured by Ube Industries, Ltd., 5033, melting point: 196℃, density: 1.14 g / cm³). 3 The intermediate layer was prepared in the same manner as in Example 1-1, except that it was changed to ). In the intermediate layer obtained in this manner, the thickness of the surface resin layer made of polyamide was 2 μm, the thickness of the adhesive resin layer was 3 μm, and the thickness of the polyethylene resin layer made of medium-density polyethylene was 20 μm.

[0143] A laminate was fabricated in the same manner as in Example 1-1, except that the intermediate layer was changed to an intermediate layer prepared as described above.

[0144] Examples 1-5 Ethylene vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., EVAL E171B, melting point: 165℃, density: 1.14 g / cm³) 3 )and, Adhesive resin (Mitsui Chemicals, Inc., Admer NF557) and Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3 (Melting point: 129°C) and compatibilizer (Dow Chemical, maleic anhydride-modified polyethylene, Retain 3000, density: 0.87 g / cm³) 3A blended resin containing ) in a ratio of 8:2 by mass, Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3 (melting point: 129°C) After co-extruding the material using the inflation molding method, an intermediate layer was fabricated by stretching it five times in the longitudinal direction (MD direction) using a stretching device. In the intermediate layer obtained in this manner, 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 blended resin was 10 μm, and the thickness of the first polyethylene resin layer composed of medium-density polyethylene was 10 μm.

[0145] A laminate was fabricated in the same manner as in Example 1-1, except that the intermediate layer was changed to an intermediate layer prepared as described above.

[0146] Examples 1-6 Ethylene vinyl alcohol copolymer is used with polyamide (manufactured by Ube Industries, Ltd., 5033, melting point: 196℃, density: 1.14 g / cm³). 3 The intermediate layer was prepared in the same manner as in Examples 1-5, except that it was changed to ). In the intermediate layer obtained in this manner, the thickness of the surface resin layer made of polyamide was 2 μm, the thickness of the adhesive resin layer was 3 μm, the thickness of the second polyethylene resin layer made of blended resin was 10 μm, and the thickness of the first polyethylene resin layer made of medium-density polyethylene was 10 μm.

[0147] A laminate was fabricated in the same manner as in Example 1-1, except that the intermediate layer was changed to an intermediate layer prepared as described above.

[0148] Comparative Example 1-1 Medium-density polyethylene (Dow Chemical, Elite 5538, density: 0.941 g / cm³) 3A single-layer extruded film was produced using the inflation molding method from a polyethylene film with a melting point of 129°C. This film was then stretched five times in the longitudinal direction (MD direction) using a stretching device to produce a 25 μm stretched polyethylene film.

[0149] A laminate was prepared in the same manner as in Example 1-1, except that the intermediate layer was changed to a stretched polyethylene film prepared as described above.

[0150] Comparative Example 1-2 A biaxially oriented polyester film with a thickness of 12 μm (manufactured by Toyobo Co., Ltd., E5100) was prepared.

[0151] A laminate was prepared in the same manner as in Example 1-1, except that the intermediate layer was changed to the polyester film described above.

[0152] Example 2-1 The laminate of the present invention was fabricated in the same manner as in Example 1-1, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0153] Example 2-2 The laminate of the present invention was fabricated in the same manner as in Examples 1-2, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0154] Examples 2-3 The laminate of the present invention was fabricated in the same manner as in Examples 1-3, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0155] Examples 2-4 The laminate of the present invention was fabricated in the same manner as in Examples 1-4, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0156] Examples 2-5 The laminate of the present invention was fabricated in the same manner as in Examples 1-5, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0157] Examples 2-6 The laminate of the present invention was fabricated in the same manner as in Examples 1-6, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0158] Comparative Example 2-1 The laminate was fabricated in the same manner as in Comparative Example 1-1, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0159] Comparative Example 2-2 The laminate was fabricated in the same manner as in Comparative Examples 1-2, except that the aluminum vapor-deposited film was replaced with a 20 nm thick aluminum oxide (alumina) vapor-deposited film formed by the PVD method.

[0160] <<Gas Barrier Properties Evaluation>> The laminates obtained in the examples and comparative examples, and the oxygen permeability of the laminates (cc / m³) 2 (day·atm) and water vapor transmission (g / m³) 2 The following method was used to measure the (day) and the results are summarized in Table 1.

[0161] [Oxygen permeability] Using an oxygen permeability measuring device (MOCON, OX-TRAN2 / 20), the test specimen was set with the substrate side facing the oxygen supply side, and the oxygen permeability was measured in accordance with JIS K 7126 under conditions of 23°C and 90% RH relative humidity. [Water vapor transmission rate] Using a water vapor transmission rate measuring device (MOCON, PERMATRAN-w 3 / 33), the test specimen was set with the substrate side facing the water vapor supply side, and the water vapor transmission rate was measured in accordance with JIS K 7129 under conditions of 40°C and 90% RH relative humidity.

[0162] <<Laminate Strength Test>> The laminates obtained in the above examples and comparative examples, as well as samples cut from the laminates into 15 mm wide strips, were tested using a tensile testing machine (Tensilon Universal Material Tester, manufactured by Orientec Co., Ltd.) in accordance with JIS K6854-2. The laminate 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) was measured using a 90° peel method (T-peel method) at a peeling speed of 50 mm / min. The measurement results are summarized in Table 1.

[0163] [Table 1] [Explanation of Symbols]

[0164] 10: Laminate, 11: Substrate, 12: Intermediate layer, 13: Sealant layer, 14: Vapor-deposited film, 15: Surface resin layer, 16: Polyethylene resin layer, 17: Adhesive resin layer, 20: Packaging bag, 30: Standing pouch, 41: Easy-open means, 42: Notch, 43: Half-cut line, 51: Extraction nozzle, 52: Curved section, 53: Cut-off section, 60: Laminate tube, 61: Laminate tube body, 62: Head, 63: Body, 64: Shoulder, 65: Outlet, 66: Cap, 67: Thread, 68: Welded section, 69: Bottom seal section

Claims

1. A laminate comprising 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 laminate is characterized in that the intermediate polyethylene resin layer and the surface resin layer are subjected to stretching treatment.

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

3. The laminate according to claim 1 or 2, wherein the difference in melting points between the polyethylene resin of the base material and the resin material with a melting point of 150°C or higher contained in the surface resin layer is 20 to 80°C.

4. The laminate according to any one of claims 1 to 3, wherein the resin material of the surface resin layer is a polymer having polar groups.

5. The laminate 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 laminate according to any one of claims 1 to 5, wherein the polyethylene resin layer of the intermediate layer has a multilayer structure.

7. The laminate according to claim 6, wherein the polyethylene resin layer of the intermediate layer comprises at least one layer containing a compatibilizer.

8. The laminate according to claim 7, wherein the surface resin layer is provided so as to be in contact with the layer containing the compatibilizer for the polyethylene resin layer.

9. The laminate according to any one of claims 1 to 8, wherein a barrier coat layer is further provided on the vapor-deposited film.

10. A laminate according to any one of claims 1 to 9, used in a packaging container.

11. The laminate according to any one of claims 1 to 10, wherein the polyethylene resin content in the entire laminate is 80% by mass or more.

12. A packaging container comprising a laminate according to any one of claims 1 to 11.

13. The packaging container according to claim 12, which is a packaging bag.

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