Laminate and packaging container

Abstract

To provide a laminate which is excellent in recyclability and gas barrier property, can reduce a used amount of plastic, prevents lowering of the gas barrier property even when being subjected to ruled line processing or bending processing, and can suppress deterioration of a content, and a packaging bag using the same.SOLUTION: A laminate 1 includes at least a paper base material layer 11, a vapor-deposited film 21 and a barrier layer 31 in this order, wherein the vapor-deposited film includes a resin film 22 and a vapor-deposited film 23, the barrier layer is a co-extrusion layer of a gas barrier resin layer 32 and an adhesive resin layer 33, the gas barrier resin layer is positioned between the vapor-deposited film and the adhesive resin layer, the gas barrier resin layer contains an ethylene-vinyl alcohol copolymer, the adhesive resin layer is composed of a resin composition containing unmodified polyolefin and maleic anhydride modified polyolefin, a content of the unmodified polyolefin in the adhesive resin layer is 10 mass% or more and 80 mass% or less, and thickness of the adhesive resin layer 33 is 3 μm or more and 20 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laminate and a packaging container. [Background technology]

[0002] Paper containers are widely used, primarily for food products. Liquid paper containers (paper containers for holding liquids) are particularly popular for milk and other beverages, seasonings, detergents, pharmaceuticals, industrial chemicals, and other products, due to the ease of direct printing on the container surface compared to plastic containers and the well-established recycling system.

[0003] In order to prevent the contents from being deteriorated by oxygen, a laminate in which aluminum foil is laminated on a paper base layer has been used as a laminate constituting a liquid paper container, and gas barrier properties have been imparted to the laminate. However, such a laminate is not suitable for recycling because it is difficult to separate the paper base layer and the aluminum foil. Furthermore, when such a laminate is incinerated for disposal, aluminum may remain as lumps and damage the incinerator. Furthermore, aluminum is used not only for liquid paper containers but also for electric vehicles, etc., and the demand for aluminum has increased with the recent spread of electric vehicles, resulting in the depletion of aluminum resources.

[0004] To solve the above problems, laminates for liquid-carrying paper containers that have high gas barrier properties without using aluminum foil have been developed. For example, instead of aluminum foil, a plastic film vapor-deposited with an inorganic compound is used to maintain the gas barrier properties of the laminates for liquid-carrying paper containers in a similar manner (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-280239 Summary of the Invention [Problem to be solved by the invention]

[0006] However, inorganic compound vapor-deposited films are generally thinner than aluminum foil. For example, while aluminum foil is approximately 7 μm thick, inorganic compound vapor-deposited films are approximately 5 nm to 300 nm thick. Furthermore, inorganic compound vapor-deposited films are generally less malleable than aluminum foil. For these reasons, cracks are likely to occur in the vapor-deposited film during the scoring and bending processes when converting a laminate for a liquid paper container with an inorganic compound vapor-deposited film into a liquid paper container. As a result, the gas barrier properties of the laminate and the liquid paper container are reduced, causing problems such as deterioration of the contents. This problem is particularly prevalent when the contents are shochu or ginjo sake. Specifically, a liquid paper container made from a laminate comprising a paper base layer and an inorganic compound vapor-deposited film has a problem of significantly worsening the flavor of shochu or ginjo sake compared to a liquid paper container made from a laminate comprising a paper base layer and aluminum foil.

[0007] Furthermore, in recent years, with the aim of reducing environmental loads such as carbon dioxide emissions, there has been a strong demand for reducing the amount of plastic used in laminates that constitute packaging containers by reducing the number and thickness of resin layers. Furthermore, reducing the amount of plastic used has the advantage of also leading to cost reduction.

[0008] Therefore, an object of the present disclosure is to provide a laminate that has excellent recyclability and gas barrier properties, can reduce the amount of plastic used, is resistant to deterioration of gas barrier properties even when subjected to creasing or bending, and can suppress deterioration of contents. Another object of the present disclosure is to provide a packaging container using the laminate. [Means for solving the problem]

[0009] The present inventors have found that the above problems can be solved by using an ethylene-vinyl alcohol copolymer, a resin with gas barrier properties. Specifically, the inventors have found that providing a gas barrier resin layer containing an ethylene-vinyl alcohol copolymer in a laminate increases the mechanical strength of the laminate and reduces the likelihood of cracks occurring in the vapor-deposited film at bent portions where stress is concentrated. This, combined with the gas barrier properties of the ethylene-vinyl alcohol copolymer itself, reduces the gas barrier properties of the laminate and packaging container, making it possible to suppress deterioration of the contents. Furthermore, the inventors have found that by forming the gas barrier resin layer into a two-layer co-extrusion layer with an adhesive resin layer of a predetermined thickness, it is possible to reduce the amount of plastic used while suppressing deterioration of gas barrier properties. The present disclosure has been completed based on these findings and through further investigation.

[0010] The present disclosure is solved by the following embodiments. <1> A laminate comprising at least a paper substrate layer, a vapor-deposited film, and a barrier layer in this order, the vapor-deposited film comprises a resin film and a vapor-deposited membrane, the barrier layer is a co-extruded layer of two layers, a gas barrier resin layer and an adhesive resin layer, the gas barrier resin layer is located between the vapor-deposited film and the adhesive resin layer, the gas barrier resin layer contains an ethylene-vinyl alcohol copolymer, the adhesive resin layer is made of a resin composition containing an unmodified polyolefin and a maleic anhydride-modified polyolefin, the content of the unmodified polyolefin in the adhesive resin layer is 10% by mass or more and 80% by mass or less, The thickness of the adhesive resin layer is 3 μm or more and 20 μm or less. <2> The vapor-deposited film is a silica vapor-deposited film. <1> The laminate according to claim 1. <3> The content of groups derived from maleic anhydride in the adhesive resin layer is 0.18% by mass or more and 0.25% by mass or less. <1> or <2> The laminate according to claim 1. <4> The melt flow rate of the resin composition is 2 g / 10 min or more and 13 g / 10 min or less. <1> ~ <3> 10. The laminate according to claim 9, wherein the first and second laminates are oriented in a direction perpendicular to the plane of the <5> The thickness of the gas barrier resin layer is 3 μm or more and 20 μm or less. <1> ~ <4> 10. The laminate according to claim 9, wherein the first and second laminates are oriented in a direction perpendicular to the plane of the <6> In the ethylene-vinyl alcohol copolymer, the content of structural units derived from ethylene is 20 mol% or more and 60 mol% or less. <1> ~ <5> 10. The laminate according to claim 9, wherein the first and second laminates are oriented in a direction perpendicular to the plane of the <7> The melt flow rate of the ethylene-vinyl alcohol copolymer is 0.1 g / 10 min or more and 15 g / 10 min or less. <1> ~ <6> 10. The laminate according to claim 9, wherein the first and second laminates are oriented in a direction perpendicular to the plane of the <8> The thickness of the barrier layer is 10 μm or more and 30 μm or less. <1> ~ <7> 10. The laminate according to claim 9, wherein the first and second laminates are oriented in a direction perpendicular to the plane of the <9> the paper base layer, the vapor deposition film, the barrier layer, and the sealant film in this order; <1> ~ <8> 10. The laminate according to claim 9, wherein the first and second laminates are oriented in a direction perpendicular to the plane of the <10> Oxygen permeability measured in accordance with JIS K 7126-2:2006 under an environment of 40°C temperature and 60% relative humidity is 0.5cc / m 2 ·day·atm or less, <1> ~ <9> 10. The laminate according to claim 9, wherein the first and second laminates are oriented in a direction perpendicular to the plane of the <11> <1> ~ <10> A packaging container comprising the laminate described in any one of the above. <12> It is a liquid paper container, <11> The packaging container described in [Effects of the Invention]

[0011] The present disclosure can provide a laminate that has excellent recyclability and gas barrier properties, can reduce the amount of plastic used, is resistant to deterioration of gas barrier properties even when subjected to creasing or bending, and can suppress deterioration of the contents. The present disclosure also provides a packaging container using the laminate. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present disclosure. [Figure 2] 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present disclosure. [Figure 3] 1 is a perspective view showing a Gabel-top type liquid paper container which is one embodiment of a packaging container of the present disclosure. FIG. [Figure 4] FIG. 1 is a perspective view showing a flat-top liquid paper container which is one embodiment of a packaging container of the present disclosure. [Figure 5] FIG. 1 is a perspective view showing a brick-shaped liquid paper container, which is one embodiment of a packaging container of the present disclosure. [Figure 6] 1 is a perspective view of a partially cut-away paper cup that is one embodiment of a packaging container of the present disclosure. [Figure 7] 1 is a partially cutaway front view of a paper cup, which is one embodiment of a packaging container of the present disclosure. [Figure 8] FIG. 1 is a plan view showing an embodiment of a laminate according to the present disclosure in which ruled lines are provided. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiments. Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

[0014] As shown in Fig. 1 , the laminate 1 of the present disclosure comprises at least a paper substrate layer 11, a vapor-deposited film 21, and a barrier layer 31, in this order. The vapor-deposited film 21 comprises a resin film 22 and a vapor-deposited film 23. The barrier layer 31 is a co-extruded layer of a gas barrier resin layer 32 and an adhesive resin layer 33. The gas barrier resin layer 32 is located between the vapor-deposited film 21 and the adhesive resin layer 33. The vapor-deposited film 23 is located between the resin film 22 and the barrier layer 31. That is, the laminate 1 shown in FIG. 1 comprises a paper substrate layer 11, a resin film 22, a vapor-deposited film 23, a gas barrier resin layer 32, and an adhesive resin layer 33 in this order.

[0015] Moreover, in one embodiment of the present disclosure, as shown in FIG. 2 , the laminate 1 includes a paper base layer 11, a vapor-deposited film 21, a barrier layer 31, and a sealant film 41, in this order. The vapor-deposited film 21 includes a resin film 22 and a vapor-deposited film 23. The barrier layer 31 is a co-extruded layer of a gas barrier resin layer 32 and an adhesive resin layer 33. The gas barrier resin layer 32 is located between the vapor-deposited film 21 and the adhesive resin layer 33. The vapor-deposited film 23 is located between the resin film 22 and the barrier layer 31. The sealant film 41 is in contact with the adhesive resin layer 33. 2 includes, in this order, a paper substrate layer 11, a resin film 22, a vapor-deposited film 23, a gas barrier resin layer 32, an adhesive resin layer 33, and a sealant film 41. The laminate 1 shown in FIG. 2 further includes a sealant film 41 on the adhesive resin layer 33 of the laminate 1 shown in FIG.

[0016] In the laminate of the present disclosure, the oxygen permeability measured in accordance with JIS K 7126-2:2006 under an environment of a temperature of 40°C and a relative humidity of 60% RH is preferably 0.5 cc / m 2 ·atm·day or less, and more preferably 0.3cc / m 2 ·atm·day or less, and more preferably 0.2cc / m 2 ·atm·day or less, and particularly preferably 0.15cc / m 2If the oxygen permeability of the laminate satisfies the above numerical range, the laminate has suitable oxygen barrier properties, and therefore when used in a packaging container, adverse effects on the contents of the packaging container can be suppressed. The laminate of the present disclosure is preferably impermeable to oxygen. Therefore, the oxygen permeability of the laminate of the present disclosure is preferably 0 cc / m 2 ·atm·day is most preferable, but 0.01cc / m 2 Atm·day or more is practical, and 0.05cc / m 2 Atm·day or more is more practical, and 0.1cc / m 2 ·atm·day or more is more practical. The oxygen permeability of the laminate is measured using an oxygen permeability measuring device, specifically by the method described in the Examples below.

[0017] Each layer constituting the laminate of the present disclosure will be described below.

[0018] [Paper base layer] The paper substrate layer is a layer containing paper. The paper substrate layer has a thickness of 100 g / m 2 More than 700g / m 2 or less, preferably 150 g / m 2 More than 600g / m 2 or less, more preferably 200 g / m 2 More than 500g / m 2 The paper base layer can be made of known paper such as fine paper, construction paper, art paper, coated paper, pure white roll paper, kraft paper, label paper with improved water resistance, cup base paper, card paper, ivory paper, paperboard such as manila cardboard, milk carton base paper, cup base paper, synthetic paper, clay-coated paper, etc.

[0019] [Thermoplastic resin layer] The laminate of the present disclosure may have a thermoplastic resin layer on the outer side of the paper substrate layer (the side of the paper substrate layer opposite to the side facing the vapor-deposited film). The thermoplastic resin layer can be formed using a thermoplastic resin that can be melted and fused to each other by heat. Examples of thermoplastic resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-α-olefin copolymers polymerized using a metallocene catalyst, polypropylene, ethylene-vinyl acetate copolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-propylene copolymers, methylpentene polymers, polybutene polymers, acid-modified polyolefin resins obtained by modifying polyolefin resins such as polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, polyvinyl acetate resins, poly(meth)acrylic resins, and polyvinyl chloride resins. Low-density polyethylene, linear low-density polyethylene, and ethylene-α-olefin copolymers polymerized using a metallocene catalyst are preferred.

[0020] The thermoplastic resin layer can be formed by melt-extruding one or more of the above resins using an extruder or the like, and laminating the melt-extrusion layer on the paper substrate layer or the anchor coat layer described below. For example, the thermoplastic resin layer is a single-layer thermoplastic resin layer containing low-density polyethylene. The thickness of the thermoplastic resin layer is, for example, 15 μm or more and 35 μm or less.

[0021] [Print layer] The laminate of the present disclosure may include a printed layer. The printed layer is a layer on which any desired printed pattern such as letters, numbers, pictures, figures, symbols, designs, etc. is formed for the purpose of decoration, indication of contents, indication of expiration date, indication of manufacturer, indication of seller, imparting aesthetic appeal, etc. The printed layer may further include a background color layer formed by printing to make the pattern stand out. When the laminate of the present disclosure includes a printed layer, the printed layer is preferably formed on either side of the paper substrate layer. When the laminate of the present disclosure includes the thermoplastic resin layer on the outer side of the paper substrate layer, the printed layer may be formed further outside the thermoplastic resin layer.

[0022] [Vapor-deposited film] The vapor-deposited film includes a resin film and a vapor-deposited film formed on the resin film. By including the vapor-deposited film, the laminate of the present disclosure has excellent gas barrier properties.

[0023] In one embodiment, the vapor-deposited film is formed on one surface of the resin film. Examples of methods for forming the vapor-deposited film on the surface of the resin film include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, ion plating, and ion cluster beam deposition, and chemical vapor deposition (CVD) methods such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0024] Examples of the vapor-deposited film include vapor-deposited films of metals or metal oxides, such as vapor-deposited films of at least one metal selected from the group consisting of silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, and yttrium, or its oxide. Among these, aluminum vapor-deposited films, alumina vapor-deposited films, and silica vapor-deposited films are preferred.

[0025] In one embodiment, the vapor-deposited film is a transparent vapor-deposited film such as an alumina vapor-deposited film or a silica vapor-deposited film. Among these, a silica vapor-deposited film is more preferable from the viewpoint that no aluminum resource is used.

[0026] The thickness of the vapor-deposited film is, for example, 5 nm to 100 nm, preferably 10 nm to 60 nm. When the thickness of the vapor-deposited film is 5 nm or more, for example, sufficient gas barrier properties are imparted. When the thickness of the vapor-deposited film is 100 nm or less, for example, the occurrence of cracks in the vapor-deposited film can be suppressed.

[0027] Examples of resin films constituting the vapor-deposited film include polyester films, polypropylene films, and polyamide films. Examples of polyester films include polyethylene terephthalate films.

[0028] In one embodiment, the resin film is preferably biaxially stretched. By using a biaxially stretched resin film, dimensional deviation of the resin film can be suppressed.

[0029] The thickness of the resin film constituting the vapor-deposited film is preferably from 5 μm to 150 μm, more preferably from 10 μm to 50 μm, which provides, for example, dimensional stability, heat resistance required during vapor deposition, and film transport suitability during processing.

[0030] Specific examples of the vapor-deposited film include aluminum-deposited polyester film, alumina-deposited polyester film, silica-deposited polyester film, aluminum-deposited polypropylene film, and silica-deposited polyamide film. In one embodiment, the vapor-deposited film is a transparent vapor-deposited film such as an alumina-deposited polyester film, a silica-deposited polyester film, or a silica-deposited polyamide film.

[0031] [Gas barrier resin layer] The gas barrier resin layer contains an ethylene-vinyl alcohol copolymer (EVOH) as a gas barrier resin, which can improve the gas barrier properties of the laminate. Furthermore, by providing the laminate with a gas barrier resin layer, the mechanical strength of the laminate is increased, and the vapor-deposited film is less likely to crack at bent portions where stress is concentrated when the laminate is creasing or bending, etc. As a result, even when the laminate is creasing or bending, the gas barrier properties of the laminate and the packaging container are less likely to deteriorate.

[0032] In the ethylene-vinyl alcohol copolymer, the content of structural units derived from ethylene (hereinafter referred to as "ethylene content") is preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 32 mol% or more, which can improve the processability of the laminate. The ethylene content of the ethylene-vinyl alcohol copolymer is preferably 60 mol % or less, more preferably 48 mol % or less, and even more preferably 44 mol % or less, which can improve the gas barrier properties of the laminate. The ethylene content of the ethylene-vinyl alcohol copolymer is a value measured by the NMR method.

[0033] The melting point (Tm) of the ethylene-vinyl alcohol copolymer is preferably 130°C or higher and 200°C or lower, more preferably 140°C or higher and 195°C or lower, and even more preferably 150°C or higher and 190°C or lower.

[0034] From the viewpoint of processability, the melt flow rate (MFR) of the ethylene-vinyl alcohol copolymer is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, even more preferably 0.5 g / 10 min or more, and particularly preferably 1 g / 10 min or more. Furthermore, from the viewpoint of facilitating the production of a laminate with good appearance, the melt flow rate of the ethylene-vinyl alcohol copolymer is preferably 15 g / 10 min or less, more preferably 10 g / 10 min or less, even more preferably 5 g / 10 min or less, and particularly preferably 4 g / 10 min or less. The melt flow rate of the ethylene-vinyl alcohol copolymer is a value measured at a temperature of 190°C and a load of 2160 g in accordance with JIS K 7210:1999. However, when the melting point of the ethylene-vinyl alcohol copolymer exceeds 190°C, the value is measured at a temperature of 210°C.

[0035] The content of the ethylene-vinyl alcohol copolymer in the gas barrier resin layer is, for example, 50% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more, thereby improving the gas barrier properties of the laminate.

[0036] The gas barrier resin layer may further contain a gas barrier resin other than the ethylene-vinyl alcohol copolymer, for example, at least one selected from the group consisting of polyamide, polyvinyl alcohol, polyacrylonitrile, polyester, polyurethane, and (meth)acrylic resin.

[0037] The gas barrier resin layer may contain various additives, such as antioxidants, slip agents, plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, release agents, ion exchange agents, antiblocking agents, and color pigments, as long as the additives do not impair the properties of the layer.

[0038] The thickness of the gas barrier resin layer is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 8 μm or more. This improves the gas barrier properties of the laminate. The thickness of the gas barrier resin layer is also preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. This allows for a reduction in the amount of resin used.

[0039] [Adhesive resin layer] The adhesive resin layer is composed of a resin composition containing an unmodified polyolefin and a maleic anhydride-modified polyolefin. Unmodified polyolefins are polyolefins that have not been modified, and examples include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polypropylene (PP). Maleic anhydride modified polyolefin is a resin in which maleic anhydride is graft polymerized onto the main chain of a polyolefin. Polyolefins that can be modified with maleic anhydride include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polypropylene (PP).

[0040] The resin composition may contain two or more unmodified polyolefins, for example, an unmodified low-density polyethylene and an unmodified linear low-density polyethylene. The resin composition may contain two or more maleic anhydride-modified polyolefins. For example, the resin composition may contain a low-density polyethylene modified with maleic anhydride and a linear low-density polyethylene modified with maleic anhydride.

[0041] The content of unmodified polyolefin in the adhesive resin layer (total content when the resin composition constituting the adhesive resin layer contains two or more unmodified polyolefins) is 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. Also, the content of unmodified polyolefin in the adhesive resin layer (total content when the resin composition constituting the adhesive resin layer contains two or more unmodified polyolefins) is 80% by mass or less, preferably 60% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. The content of maleic anhydride-modified polyolefin in the adhesive resin layer (total content when the resin composition constituting the adhesive resin layer contains two or more types of maleic anhydride-modified polyolefin) is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, and particularly preferably 70% by mass or more. Furthermore, the content of maleic anhydride-modified polyolefin in the adhesive resin layer (total content when the resin composition constituting the adhesive resin layer contains two or more types of maleic anhydride-modified polyolefin) is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and particularly preferably 75% by mass or less.

[0042] The content of unmodified polyolefin and the content of maleic anhydride-modified polyolefin in the adhesive resin layer can be analyzed from peaks detected by, for example, differential scanning calorimetry (DSC), infrared spectroscopy (IR), or nuclear magnetic resonance (NMR).

[0043] Because the resin composition constituting the adhesive resin layer contains an unmodified polyolefin in addition to a maleic anhydride-modified polyolefin, the content of maleic anhydride-derived groups in the adhesive resin layer is smaller than that of adhesive resin layers formed from commercially available maleic anhydride-modified polyolefins. In the present disclosure, the content of maleic anhydride-derived groups in the adhesive resin layer is preferably 0.29% by mass or less, more preferably 0.25% by mass or less, and even more preferably 0.23% by mass or less. This reduces adhesion of the adhesive resin layer to manufacturing equipment (metal chill rolls, rubber nip rolls, etc.) during the laminate manufacturing process. Furthermore, the content of maleic anhydride-derived groups in the adhesive resin layer is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, and even more preferably 0.2% by mass or more. This improves adhesion of the adhesive resin layer to the gas barrier resin layer, preventing delamination of the laminate. The content of the group derived from maleic anhydride in the adhesive resin layer is the ratio of the mass of the group derived from maleic anhydride (-C4H3O3) to the mass of all components constituting the adhesive resin layer. The content of the group derived from maleic anhydride in the adhesive resin layer is measured by infrared absorption spectroscopy, specifically by the method described in the examples below.

[0044] From the viewpoint of processability, the melt flow rate of the resin composition is preferably 2 g / 10 min or more, more preferably 5 g / 10 min or more, and even more preferably 6 g / 10 min or more. The melt flow rate of the resin composition is preferably 13 g / 10 min or less, more preferably 10 g / 10 min or less, and even more preferably 7 g / 10 min or less, from the viewpoint of facilitating the production of a laminate with good appearance. The melt flow rate of the resin composition is a value measured in accordance with JIS K 7210:1999 under conditions of a temperature of 190° C. and a load of 2160 g.

[0045] The resin composition may further contain other resins in addition to the unmodified polyolefin and the maleic anhydride-modified polyolefin, such as at least one resin selected from the group consisting of polyolefins modified with substances other than maleic anhydride (e.g., maleic acid, fumaric acid, esters, or metal salts), vinyl resins, polyethers, polyesters, polyamides, polyurethanes, silicone resins, epoxy resins, and phenolic resins.

[0046] The resin composition may contain various additives within the range that does not impair the properties, such as antioxidants, slip agents, plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, mold release agents, ion exchange agents, antiblocking agents, and color pigments.

[0047] The thickness of the adhesive resin layer is 3 μm or more, preferably 6 μm or more, and more preferably 9 μm or more. This makes it easier to heat the entire coextruded layer to a high temperature when extruding the resin composition in the process of producing a laminate. As a result, the layers are sufficiently fused together, maintaining the adhesive strength between the layers of the produced laminate and preventing delamination. Furthermore, the thickness of the adhesive resin layer is 20 μm or less, preferably 15 μm or less, and more preferably 10 μm or less. This allows for a reduction in the amount of resin used.

[0048] [Barrier layer] The barrier layer is a coextruded layer of two layers, a gas barrier resin layer and an adhesive resin layer. The coextruded layer is a layer formed by a coextrusion method. Unlike the dry lamination method, which simply bonds individual films together, the co-extrusion method involves extruding multiple molten resins through multiple narrow slit-like gaps. Therefore, the interface between layers formed by the co-extrusion method exhibits a very unique structure. This structure is significantly different from the interlayer structure resulting from entanglement interactions, such as self-adhesion, produced by the dry lamination method. Specifically, the interface between layers formed by the co-extrusion method forms an interlocking structure in which the crystals of each resin interpenetrate, resulting in a very complex structure.

[0049] The barrier layer can be formed, for example, by co-extruding the resin that constitutes the gas barrier resin layer and the resin composition that constitutes the adhesive resin layer. More specifically, the barrier layer can be produced by simultaneously extruding two layers, an ethylene-vinyl alcohol copolymer and an adhesive resin, onto a vapor-deposited film using a co-extrusion molding device. Note that the barrier layer produced by the co-extrusion method is an unstretched layer.

[0050] From the viewpoint of obtaining a laminate with excellent gas barrier properties, the thickness of the barrier layer is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 16 μm or more. Also, from the viewpoint of reducing the amount of resin used, the thickness of the barrier layer is preferably 30 μm or less, more preferably 24 μm or less, and even more preferably 20 μm or less.

[0051] Conventionally, there have been barrier layers that are three-layer coextrusion layers formed by coextrusion of three types of resins: ethylene-vinyl alcohol copolymer, maleic anhydride-modified polyolefin, and unmodified polyolefin resin. Ethylene-vinyl alcohol copolymer and maleic anhydride-modified polyolefin can change color and emit odors or foreign matter due to decomposition at high temperatures, whereas unmodified polyolefin is less susceptible to such phenomena. For this reason, unmodified polyolefin can be said to be a resin with relatively excellent heat resistance. In prior art coextrusion of three types of resins, the unmodified polyolefin, which has excellent heat resistance, is extruded at a high temperature, and the entire coextruded layer is heated to a high temperature, thereby fusing the layers together and increasing the adhesive strength between the layers. When unmodified polyolefin is excluded from the three resins used for coextrusion and a two-layer film is produced by coextrusion of an ethylene-vinyl alcohol copolymer and a maleic anhydride-modified polyolefin, the absence of the heat-resistant unmodified polyolefin in the coextruded layer makes it difficult to maintain the entire coextruded layer at a high temperature, making it difficult for the coextruded layers to fuse together, and reducing the adhesive strength between the ethylene-vinyl alcohol copolymer layer and the maleic anhydride-modified polyolefin layer. As a result, problems such as delamination and reduced gas barrier properties occur more easily. Furthermore, if maleic anhydride-modified polyolefin is excluded from the three resins used for coextrusion and a two-layer film is produced by coextrusion of an ethylene-vinyl alcohol copolymer and an unmodified polyolefin, the adhesive strength between the ethylene-vinyl alcohol copolymer layer and the unmodified polyolefin layer tends to decrease because the maleic anhydride-modified polyolefin, which has excellent adhesive properties, is not present in the coextruded layer. As a result, interlayer delamination tends to occur, and problems such as a decrease in gas barrier properties occur. In the present disclosure, instead of forming a layer of unmodified polyolefin and a layer of maleic anhydride-modified polyolefin as separate layers, a single layer is formed from a resin composition in which unmodified polyolefin and maleic anhydride-modified polyolefin are mixed in a certain ratio, and the barrier layer is a co-extruded layer of two layers, a gas barrier resin layer and an adhesive resin layer, thereby achieving both a reduction in the amount of resin used and excellent gas barrier properties.

[0052] [Sealant film] The sealant film is a film with excellent heat sealing properties. By providing the laminate with the sealant film, the sealant film can be melted by heating or the like to perform heat sealing in which the sealant films are fused together or the sealant film is fused to the thermoplastic resin layer, and a packaging container can be easily produced from the laminate. Specific examples of heat sealing include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, and ultrasonic sealing.

[0053] The adhesion between the paper substrate layer and the vapor-deposited film, or the adhesion between the sealant film and the barrier layer, can be achieved by dry lamination using a solvent-based adhesive, or by non-solvent lamination using a solvent-free adhesive. This method provides excellent adhesive strength. Examples of adhesives that can be used include two-component curing polyurethane adhesives. Alternatively, the paper substrate layer and the vapor-deposited film or the sealant film and the barrier layer can be bonded together by extrusion lamination (the so-called sandwich lamination method) via an adhesive layer. In this case, the adhesive layer can be made of a polyolefin-based thermal adhesive resin (e.g., LDPE), as well as a simple substance such as an ethylene-methacrylic acid copolymer, an ethylene-acrylic acid copolymer, or an ionomer, or a resin obtained by blending these with an adhesion improver such as a hard resin.

[0054] Alternatively, the sealant film and the barrier layer can be bonded together by co-extrusion of a gas barrier resin layer and an adhesive resin layer onto a vapor-deposited film, laminating the vapor-deposited film and the sealant film with the gas barrier resin layer and the adhesive resin layer interposed therebetween, and bonding them together by a co-extrusion method. This makes it possible to omit a dry laminate layer or adhesive layer between the adhesive resin layer and the sealant film, thereby reducing the amount of resin used.

[0055] [Middle layer] The laminate according to the present disclosure may have an intermediate layer between the paper substrate layer and the vapor-deposited film or between the sealant film and the barrier layer. Examples of the intermediate layer include a light-shielding layer and a strength-improving layer.

[0056] The adhesion between the intermediate layer and other layers can be carried out by dry lamination, non-solvent lamination, extrusion lamination, co-extrusion, etc., in the same manner as the adhesion between the paper base layer and the vapor-deposited film or the adhesion between the sealant film and the barrier layer.

[0057] In either case, the adhesive strength between the layers can be increased by pretreating the lamination surfaces, such as corona treatment or application of an anchor coating agent to form an anchor coating layer. For example, the paper substrate layer and the vapor-deposited film can be bonded together by applying an anchor coating agent to one side of the paper substrate layer to form an anchor coating layer, extruding a resin that will form an adhesive layer onto the anchor coating layer, and laminating the vapor-deposited film via the adhesive layer. In this case, the laminate has the anchor coating layer and adhesive layer between the paper substrate layer and the vapor-deposited film (not shown). For example, an anchor coating agent can be applied to one side of a vapor-deposited film to form an anchor coating layer, and a gas barrier resin layer and an adhesive resin layer can be co-extruded onto the anchor coating layer to form a barrier layer. In this case, the laminate has an anchor coating layer between the vapor-deposited film and the gas barrier resin layer (not shown).

[0058] [Anchor coat layer] The laminate of the present disclosure may further include an anchor coat layer between any layers, such as between the paper substrate layer and the vapor-deposited film, or between the vapor-deposited film and the barrier layer. This improves interlayer adhesion. The anchor coat layer is formed from an anchor coating agent.

[0059] Examples of the anchor coating agent include polyurethane-based, polyolefin-based, and epoxy resin-based anchor coating agents. In one embodiment, the anchor coating agent is a two-component curing resin, and is composed of, for example, a polyol as a base agent and a polyisocyanate as a curing agent.

[0060] Examples of polyols include polyether polyols, polyester polyols, and (meth)acrylic polyols. Examples of polyisocyanates include aromatic polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and polymethylene polyphenylene polyisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate.

[0061] In one embodiment, the anchor coat layer is made of polyurethane obtained by reacting a polyol with a polyisocyanate. Specific examples of polyurethane include polyether polyurethane, polyester polyurethane, and poly(meth)acrylic polyurethane.

[0062] The anchor coating layer can be formed, for example, by applying an anchor coating agent to one surface of a paper substrate layer or a laminate surface such as the vapor-deposited surface of a vapor-deposited film. The anchor coating agent can be applied by a coating method such as roll coating, gravure roll coating, or kiss coating, or by a printing method.

[0063] The dry coating amount of the anchor coating agent is, for example, 0.01 g / m 2 More than 1g / m 2 or less, preferably 0.03 g / m 2 More than 0.5g / m 2 or less, more preferably 0.05 g / m 2 More than 0.4g / m 2 The following is the result.

[0064] The thickness of the anchor coat layer is, for example, 0.05 μm or more and 3.0 μm or less, preferably 0.1 μm or more and 2.0 μm or less, and more preferably 0.2 μm or more and 1.0 μm or less.

[0065] [Packaging container] The laminate of the present disclosure can be suitably used for packaging containers. Examples of packaging containers include packaging bags, lids, laminated tubes, liquid containers, paper cups, various label materials, etc. Examples of packaging bags include various types of packaging bags such as standing pouch type, side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, palm seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type. The thickness of the laminate can be appropriately determined depending on its application. For example, by reducing the thickness of the laminate, the stiffness of the laminate itself can be reduced, improving its suitability for packaging machines such as bag-making machines and filling machines. The thickness of the laminate is, for example, 30 μm or more and 300 μm or less, preferably 35 μm or more and 180 μm or less.

[0066] [Liquid paper container] A case where a liquid-storing paper container is formed using the laminate of the present disclosure will be described. Fig. 3 is a perspective view showing an example of a liquid-storing paper container 60. As shown in Fig. 3, the liquid-storing paper container 60 has a rectangular cylindrical body 61 including a side surface, a rectangular plate-shaped bottom 62, and an upper portion 63. The upper portion 63 has a pair of opposing inclined plates 63a and a pair of folded portions 64 that are located between the inclined plates 63a and are folded between the inclined plates 63a. An adhesive tab 65 is provided at the upper end of each of the pair of inclined plates 63a, and the pair of inclined plates 63a are adhered to each other by the adhesive tab 65 provided at the upper end of each of the pair of inclined plates 63a. A spout may be attached to one of the pair of inclined plates 63a, and the spout may be sealed with a cap.

[0067] The liquid paper container 60 can be manufactured by a conventionally known method using the laminate of the present disclosure. For example, the laminate can be made into a box to produce liquid paper containers 60 of various shapes, such as a gable-roof type with a gable roof at the top, a flat-top type with a flat top and a spout stopper, and a brick type with a flat top and a rectangular brick shape with a straw hole. An example of a gable-top type liquid paper container is a liquid paper container 60 having a gable-top top 63 as shown in FIG. An example of a flat-top liquid paper container is a liquid paper container 60 having a flat top 63 and a spout plug 66, as shown in FIG. An example of a brick-shaped liquid paper container is a liquid paper container 60 having a flat top 63 and a straw hole 67, as shown in FIG.

[0068] The liquid paper container 60 can be suitably used as a packaging paper container for all types of liquids, including alcoholic beverages such as sake, shochu, and wine, dairy drinks such as milk, soft drinks such as orange juice and tea, and chemical products such as car wax, shampoo, and detergent.

[0069] [Paper cups] Next, a paper cup formed using the laminate of the present disclosure will be described. Fig. 6 is a perspective view of a paper cup with a portion cut away. As shown in Fig. 6, paper cup 70 has a cylindrical body 72 with a flange 71 at the top and a diameter that gradually widens towards the opening, and a bottom 73 provided at the lower end (one end) of body 72. Body 72 has flange 71 that is rounded outward at its upper end. After the contents are placed inside paper cup 70, it may be sealed by adhering a lid (not shown) along flange 71 of body 72. It is preferable that the lid has gas barrier properties. The paper cup 70 can be manufactured by a conventionally known method using the laminate of the present disclosure for the body 72. However, the paper cup of the present disclosure is not limited to this, and the bottom 73 may be formed using the laminate of the present disclosure, or both the body 72 and the bottom 73 may be formed using the laminate of the present disclosure.

[0070] Furthermore, as shown in Fig. 7, the paper cup 70 may have an outer casing 74 on the outer periphery of the body 72. The outer casing 74 may be made of paper, for example. The body 72 has a protrusion 75 formed thereon. The protrusion 75 is formed to provide an air gap 76 between the body 72 and the outer casing 74. One or more protrusions 75 may be provided in the horizontal direction, and for example, two protrusions may be provided as shown in Fig. 7. [Example]

[0071] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples.

[0072] The various raw materials used in the laminates of the following Examples and Comparative Examples are as follows. Gas barrier resin A Ethylene-vinyl alcohol copolymer, product name: F171B, manufactured by Kuraray Co., Ltd., ethylene content: 32 mol%, melt flow rate: 1.7 g / 10 min (measured at 190°C) Gas barrier resin B Ethylene-vinyl alcohol copolymer, product name: F104B, manufactured by Kuraray Co., Ltd., ethylene content: 32 mol%, melt flow rate: 4.4 g / 10 min (measured at 190°C) Gas barrier resin C Ethylene-vinyl alcohol copolymer, product name: E173B, manufactured by Kuraray Co., Ltd., ethylene content: 44 mol%, melt flow rate: 2.5 g / 10 min (measured at 190°C) Gas barrier resin D Ethylene-vinyl alcohol copolymer, trade name: DC3212B, manufactured by Mitsubishi Chemical Corporation, ethylene content: 32 mol%, melt flow rate: 12 g / 10 min (measured at 210°C) ·Adhesive resin A A resin composition obtained by mixing 60% by mass of linear low-density polyethylene modified with maleic anhydride (trade name: NE827, manufactured by Mitsui Chemicals, Inc.; melt flow rate measured at 190°C: 5.6 g / 10 min) and 40% by mass of unmodified low-density polyethylene (trade name: CE4009, manufactured by Sumitomo Chemical Co., Ltd.; melt flow rate measured at 190°C: 7.0 g / 10 min). Melt flow rate of adhesive resin A: 6.2 g / 10 min (measured at 190°C) ·Adhesive resin B A resin composition obtained by mixing 20% ​​by mass of maleic anhydride-modified low-density polyethylene (product name: 40E710, manufactured by Dow Chemical Japan Co., Ltd.; melt flow rate measured at 190°C: 2.5 g / 10 min) and 80% by mass of unmodified low-density polyethylene (product name: CE4009, manufactured by Sumitomo Chemical Co., Ltd.; melt flow rate measured at 190°C: 7.0 g / 10 min). Melt flow rate of adhesive resin B: 6.1 g / 10 min (measured at 190 ° C)

[0073] [Example 1] As the vapor-deposited film, a polyethylene terephthalate film (trade name: IB-PET, manufactured by Dai Nippon Printing Co., Ltd., thickness: 12 μm) having a silica vapor-deposited film formed on one side thereof was prepared. On the silica vapor deposition film of the vapor deposition film, 0.4 g / m of urethane anchor coating agent was applied. 2 An anchor coat layer was formed by applying a dry coating amount of 10 μm. Gas barrier resin A and adhesive resin A were co-extruded onto the anchor coat layer using a co-extruder, and a polyethylene film (trade name: M2005, manufactured by Aicello Co., Ltd., thickness: 40 μm) serving as a sealant film was then bonded to the anchor coat layer via the gas barrier resin A and adhesive resin A. The thickness of the gas barrier resin layer made of gas barrier resin A was 10 μm, and the thickness of the adhesive resin layer made of adhesive resin A was 10 μm. Next, milk carton base paper (manufactured by Clearwater Paper Corporation, basis weight: approximately 400 g / m) was used as the paper base layer. 2 ) on one side of which polyethyleneimine anchor coating agent was applied at 0.1 g / m 2Onto the anchor coat layer, low-density polyethylene (product name: LC520, manufactured by Sumitomo Chemical Co., Ltd., melt flow rate measured at 190°C: 3.6 g / 10 min) was extruded using an extruder to a thickness of 25 μm. Furthermore, a polyethyleneimine-based anchor coat agent was applied to the other side of the paper substrate layer in an amount of 0.1 g / m. 2 An ethylene-methacrylic acid copolymer (trade name: N1108C, manufactured by Dow Mitsui Polychemicals Co., Ltd., melt flow rate measured at 190°C: 10 g / 10 min) was extruded onto the anchor coat layer using an extruder to a thickness of 20 μm, and the layer was bonded to the surface of the polyethylene terephthalate film via an adhesive layer made of the ethylene-methacrylic acid copolymer. In this way, a laminate of Example 1 was obtained, in which a thermoplastic resin layer, an anchor coat layer, a paper base layer, an anchor coat layer, an adhesive layer, a resin film, a vapor deposition film, an anchor coat layer, a gas barrier resin layer, an adhesive resin layer, and a sealant film were laminated in this order.

[0074] [Example 2] A laminate of Example 2 was obtained in the same manner as in Example 1, except that the thickness of the gas barrier resin layer was adjusted to 5 μm.

[0075] [Example 3] A laminate of Example 3 was obtained in the same manner as in Example 1, except that the thickness of the gas barrier resin layer was adjusted to 8 μm.

[0076] [Example 4] A laminate of Example 4 was obtained in the same manner as in Example 1, except that the thickness of the gas barrier resin layer was adjusted to 15 μm.

[0077] [Example 5] A laminate of Example 5 was obtained in the same manner as in Example 1, except that gas barrier resin B was used instead of gas barrier resin A as the gas barrier resin.

[0078] [Example 6] A laminate of Example 6 was obtained in the same manner as in Example 1, except that gas barrier resin C was used instead of gas barrier resin A as the gas barrier resin.

[0079] [Example 7] A laminate of Example 7 was obtained in the same manner as in Example 1, except that gas barrier resin D was used instead of gas barrier resin A as the gas barrier resin.

[0080] [Example 8] A laminate of Example 8 was obtained in the same manner as in Example 1, except that adhesive resin B was used instead of adhesive resin A as the adhesive resin.

[0081] [Comparative Example 1] A laminate of Comparative Example 1 was obtained in the same manner as in Example 1, except that low-density polyethylene (product name: CE4009, manufactured by Sumitomo Chemical Co., Ltd., melt flow rate measured at 190°C: 7.0 g / 10 min) was used instead of gas barrier resin A and adhesive resin A.

[0082] Comparative Example 2 The laminate of Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that a three-layer film (trade name: Diamilon (registered trademark), manufactured by Mitsubishi Chemical Corporation, thickness: 120 μm) consisting of a layer of polyethylene, a layer of ethylene-vinyl alcohol copolymer, and a layer of polyethylene laminated in that order was used instead of the sealant film.

[0083] Comparative Example 3 The paper base layer is milk carton base paper (manufactured by Clearwater Paper Corporation, basis weight: approximately 400 g / m 2 ) on one side of which polyethyleneimine anchor coating agent was applied at 0.1 g / m 2Onto the anchor coat layer, low-density polyethylene (product name: LC520, manufactured by Sumitomo Chemical Co., Ltd., melt flow rate measured at 190°C: 3.6 g / 10 min) was extruded using an extruder to a thickness of 25 μm. In addition, a polyethyleneimine-based anchor coat agent was applied to the other surface of the paper substrate layer at a dry coating amount of 0.1 g / m. 2 An ethylene-methacrylic acid copolymer (trade name: N1108C, manufactured by Dow Mitsui Polychemicals Co., Ltd., melt flow rate measured at 190°C: 10 g / 10 min) was extruded onto the anchor coat layer using an extruder to a thickness of 20 μm, and an aluminum foil (trade name: 1N30, manufactured by Toyo Aluminum Co., Ltd., thickness: 7 μm) was attached via an adhesive layer made of the ethylene-methacrylic acid copolymer. On the aluminum foil, 0.4 g / m of urethane anchor coating agent was applied. 2 A low-density polyethylene (product name: CE4009, manufactured by Sumitomo Chemical Co., Ltd., melt flow rate measured at 190°C: 7.0 g / 10 min) was extruded onto the anchor coat layer, and a polyethylene film (product name: M2005, manufactured by Aicello Co., Ltd., thickness: 40 μm) was laminated to the anchor coat layer via a thermoplastic resin layer made of low-density polyethylene. In this way, a laminate of Comparative Example 3 was obtained, in which a thermoplastic resin layer, an anchor coat layer, a paper base layer, an anchor coat layer, an adhesive layer, an aluminum foil, an anchor coat layer, a thermoplastic resin layer, and a sealant film were laminated in that order.

[0084] The layer structures of the laminates of Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 1.

[0085] [Measurement of the content of groups derived from maleic anhydride in the adhesive resin layer] A Ge prism was pressed against adhesive resins A and B, and infrared absorption spectra were measured under the following measurement conditions using a Fourier transform infrared spectrometer (product name: Nicolet 6700, manufactured by Thermo Scientific). Wavenumber: approximately 1700 cm -1The appearance of a peak of the group derived from maleic anhydride was confirmed, and the content of the group derived from maleic anhydride was calculated from the peak absorption intensity. The measurement results are shown in Table 1. (Measurement conditions) Incident angle: 45 degrees Resolution: 4cm -1 Measurement wavenumber range: 700 to 4000 cm -1 Accumulation count: 64 times

[0086] [Table 1]

[0087] [Evaluation of processing suitability] Ruled lines were provided in each of the laminates of Examples 1 to 8 and Comparative Examples 1 to 3. Specifically, ruled lines 9 were provided in laminate 1 so that rectangular back panel 45, side panel 46, front panel 47, side panel 48, and adhesive strip 49 were arranged consecutively in one direction. In addition, a line 9 is provided in the laminate 1 so that a ceiling back panel 50 is connected to the upper end of the back panel 45, a bottom panel 55 is connected to the lower end of the back panel 45, a ceiling side panel 51 is connected to the upper end of the side panel 46, a bottom panel 56 is connected to the lower end of the side panel 46, a ceiling front panel 52 is connected to the upper end of the front panel 47, a bottom panel 57 is connected to the lower end of the front panel 47, a ceiling side panel 53 is connected to the upper end of the side panel 48, a bottom panel 58 is connected to the lower end of the side panel 48, a glue tab 54 is connected to the upper end of the glue tab 49, and a glue tab 59 is connected to the lower end of the glue tab 49 (see Figure 8). Next, the laminate 1 was folded along the crease 9 and thermally bonded with the adhesive tabs 49, 54, and 59 to form a cylindrical shape. Specifically, the adhesive tab 49 connected to the side panel 48 at one end was thermally bonded to the back panel 45 at the other end, the adhesive tab 54 connected to the ceiling side panel 53 at one end was thermally bonded to the ceiling back panel 50 at the other end, and the adhesive tab 59 connected to the bottom panel 58 at one end was thermally bonded to the bottom panel 55 at the other end, thereby forming a cylindrical body that was closed in the circumferential direction. In Examples 1 to 8 and Comparative Examples 1 and 3, the laminate 1 was sufficiently bent along the crease 9, and the laminate 1 could be processed into a cylindrical shape. On the other hand, in Comparative Example 2, the laminate 1 was too rigid and rebounded even when bent along the crease 9, making it impossible to process the laminate 1 into a cylindrical shape. For Examples 1 to 8 and Comparative Examples 1 and 3 that could be processed into a cylindrical shape, the bottom plates 55 to 58 were then folded along the score line 9 and fixed by thermal adhesion to form the bottom. In this way, liquid-storing paper containers with an open top were produced. The evaluation results for suitability for processing into liquid paper containers are shown in Table 2. The evaluation criteria are as follows: (Evaluation criteria) A: The laminate was bent sufficiently at the crease, and the laminate could be processed into a cylindrical shape. B: The laminate was so rigid that it rebounded even when bent along the score lines, making it impossible to process the laminate into a cylindrical shape.

[0088] [Recycling suitability evaluation] The recyclability of each of the laminates of Examples 1 to 8 and Comparative Examples 1 to 3 was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2. (Evaluation criteria) A: It does not use aluminum in the laminate and can be recycled as a paper carton. B: Aluminum is used in the laminate, making it difficult to recycle as a paper carton.

[0089] [Calculation of plastic mass percentage] For each of the laminates of Examples 1 to 8 and Comparative Examples 1 to 3, the mass proportion of plastic contained in the laminate was calculated by adding up the mass per unit area of ​​the layers other than the anchor coat layer that were made of resin, and dividing this by the sum of the mass per unit area of ​​all layers other than the anchor coat layer and the vapor deposition film. At that time, the estimated density of the polyethylene film (trade name: M2005, manufactured by Aicello Co., Ltd., thickness: 40 μm) used in Examples 1 to 8 and Comparative Examples 1 and 3 was 0.91 g / cm 3 The predicted density of the three-layer film used in Comparative Example 2 (trade name: Diamilon (registered trademark), manufactured by Mitsubishi Chemical Corporation, thickness: 120 μm) was 0.91 g / cm 3 The following values ​​were used as the densities of the resin and aluminum foil. Ethylene-vinyl alcohol copolymer: 1.19 g / cm 3 Modified or unmodified low-density polyethylene: 0.92 g / cm 3 Modified linear low-density polyethylene: 0.92 g / cm 3 Ethylene-methacrylic acid copolymer: 0.94 g / cm 3 Polyethylene terephthalate: 1.35g / cm 3 Aluminum foil: 2.7g / cm 3 The mass of the anchor coat layer and the silica vapor deposition film were not taken into account when calculating the mass ratio of plastic because they are thinner than the other layers and it was thought that the impact of their mass on the calculation results would be small relative to the mass of the entire laminate. The calculation results are shown in Table 2.

[0090] [Oxygen permeability measurement] The laminates of Examples 1 to 8 and Comparative Examples 1 and 2 were set so that the thermoplastic resin layer of the laminate was on the oxygen supply side using an oxygen permeability measuring device (model name: OX-TRAN 2 / 21, manufactured by Modern Control (MOCON)). The oxygen permeability (unit: cc / m) was measured in accordance with JIS K 7126-2:2006 under an environment of a temperature of 40°C and a relative humidity of 60%. 2 ·atm·day) was measured. Furthermore, for Examples 1 to 8 and Comparative Example 1, the oxygen permeability (unit: cc / pkg·atm·day) was measured in an environment of a temperature of 40°C and a relative humidity of 60% RH for the liquid-carrying paper containers used to evaluate processability. The lower the oxygen permeability, the better the gas barrier properties of the laminate and liquid-storing paper container. The measurement results are shown in Table 2.

[0091] [Table 2]

[0092] [Sensory evaluation] For Examples 1 to 8 and Comparative Examples 1 and 3, sake and sweet potato shochu were poured into the liquid paper containers used to evaluate processability from the top. Next, the front ceiling panel 52, rear ceiling panel 50, side ceiling panel 51, and side ceiling panel 53 were folded along the line 9, and the containers were filled by heat bonding at the designated locations. After leaving the contents sealed for one month, the flavors of the sake and sweet potato shochu were evaluated by five randomly selected testers (Testers 1 to 5). The flavor evaluation criteria were as follows: (Flavor evaluation criteria) A: Better than Comparative Example 3. B: Equivalent to Comparative Example 3. C: Slightly inferior to Comparative Example 3. D: Significantly inferior to Comparative Example 3. Furthermore, an overall evaluation was conducted for each of the sake and sweet potato shochu based on the evaluation results of all the testers. The evaluation criteria for the overall evaluation were as follows: (Evaluation criteria for overall evaluation) A: The flavor preservation effect is superior to that of Comparative Example 3. B: The flavor preservation effect is equivalent to that of Comparative Example 3. C: The flavor preservation effect is slightly inferior to that of Comparative Example 3. D: The flavor preservation effect is significantly inferior to that of Comparative Example 3. The evaluation results are shown in Table 3. Note that Comparative Example 3 was not evaluated because it was a standard.

[0093] [Table 3]

[0094] As is clear from Tables 1 to 3 above, the laminates of Examples 1 to 8, from which liquid-storing paper containers could be fabricated, were more suitable for processing than the laminate of Comparative Example 2 and more suitable for recycling than the laminate of Comparative Example 3. Furthermore, in the laminates of Examples 1 to 8, the proportion of plastic used was smaller than that of the laminate of Comparative Example 2, and the amount of plastic used could be reduced. Furthermore, the laminates of Examples 1 to 8 and the liquid-storing paper containers made from these laminates had lower oxygen permeability and better gas barrier properties than the laminate of Comparative Example 1 and the liquid-storing paper containers made from this laminate. Furthermore, it was found that the liquid paper containers made from the laminates of Examples 1 to 8 had the same flavor retention effect as the liquid paper container made from the laminate of Comparison Example 3, and were able to suppress deterioration of the contents to the same extent as conventional liquid paper containers using aluminum foil. [Explanation of symbols]

[0095] 1. Laminate 9. Borders 11 Paper base layer 21 Vapor-deposited film 22 Resin film 23 Vapor-deposited film 31 Barrier Layer 32 Gas barrier resin layer 33 Adhesive resin layer 41 Sealant Film 45 Back plate 46 Side plate 47 Front plate 48 Side plate 49 Glue allowance piece 50 Ceiling back panel 51 Ceiling side panel 52 Ceiling front plate 53 Ceiling side panel 54 Glue allowance piece 55 Bottom plate 56 Bottom plate 57 Bottom plate 58 Bottom plate 59 Glue allowance piece 60 Liquid paper containers 61 Torso 62 Bottom 63 Upper 63a Inclined plate 64 Folding section 65 Glue allowance 66 Spout stopper 67 Straw Hole 70 paper cups 71 Flange 72 Torso 73 Bottom 74 Exterior body 75 convex part 76 Gap

Claims

1. A laminate comprising at least a paper substrate layer, a vapor-deposited film, and a barrier layer in this order, the vapor-deposited film comprises a resin film and a vapor-deposited membrane, the barrier layer is a co-extruded layer of two layers, a gas barrier resin layer and an adhesive resin layer, the gas barrier resin layer is located between the vapor-deposited film and the adhesive resin layer, the gas barrier resin layer contains an ethylene-vinyl alcohol copolymer, the adhesive resin layer is made of a resin composition containing an unmodified polyolefin and a maleic anhydride-modified polyolefin, the content of the unmodified polyolefin in the adhesive resin layer is 10% by mass or more and 80% by mass or less, The thickness of the adhesive resin layer is 3 μm or more and 20 μm or less.

2. The laminate according to claim 1 , wherein the vapor-deposited film is a silica vapor-deposited film.

3. 3. The laminate according to claim 1, wherein the content of groups derived from maleic anhydride in the adhesive resin layer is 0.18% by mass or more and 0.25% by mass or less.

4. The laminate according to claim 1 or 2, wherein the resin composition has a melt flow rate of 2 g / 10 min or more and 13 g / 10 min or less.

5. The laminate according to claim 1 or 2, wherein the gas barrier resin layer has a thickness of 3 μm to 20 μm.

6. 3. The laminate according to claim 1, wherein the ethylene-vinyl alcohol copolymer has a content of structural units derived from ethylene of 20 mol % or more and 60 mol % or less.

7. 3. The laminate according to claim 1, wherein the ethylene-vinyl alcohol copolymer has a melt flow rate of 0.1 g / 10 min or more and 15 g / 10 min or less.

8. The laminate according to claim 1 or 2, wherein the barrier layer has a thickness of 10 μm or more and 30 μm or less.

9. The laminate according to claim 1 or 2, comprising the paper base layer, the vapor-deposited film, the barrier layer, and a sealant film, in this order.

10. The oxygen permeability measured in accordance with JIS K 7126-2:2006 under an environment of 40°C temperature and 60% RH is 0.5 cc / m ２ 3. The laminate according to claim 1 or 2, wherein the viscosity is 1000 kJ / day atm or less.

11. A packaging container comprising the laminate according to claim 1 or 2.

12. The packaging container according to claim 11, which is a liquid paper container.

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