Laminate, packaging body, and packaging article

Abstract

To provide a laminate that contains polyethylene and is suitable for recycling, the laminate having excellent heat resistance and strength, and a packaging body and a packaging article that include the laminate.SOLUTION: A laminate (10A1) comprises a base material layer (1), an adhesive layer (3), and a sealant layer (2) in this order. The base material layer (1) and the sealant layer (2) contain polyethylene. The degree of crystallization in the base material layer (1) is 35% or greater, the degree of crystallization being a ratio of the crystal peak area to the total peak area as measured within a range of a diffraction angle of 10-30° through a parallel beam technique in X-ray diffraction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate, a package and a packaged article. [Background technology]

[0002] Packaging materials used in packaging bags and the like are required to have various properties depending on the application. Examples of required properties include heat resistance, transparency, heat sealability, strength, gas barrier properties, puncture resistance, visibility, bag-making suitability, printability, transport suitability, etc. In order to fully satisfy each of these various performance requirements, it has been common practice to use a combination of multiple types of synthetic resin films with different properties (see, for example, Patent Document 1).

[0003] In recent years, with the growing demand for the creation of a recycling-oriented society, there has been a demand for packaging materials with high recyclability. Generally, packaging materials are considered to have high recyclability when the proportion of the main resin contained in the material is 90% by mass or more. However, as described above, conventional packaging materials are composed of different resin materials, and since it is difficult to separate the resin materials after use, they cannot be recycled as individual materials. Therefore, even if packages formed using conventional packaging materials are recovered, the only option is to burn them and recover and reuse them as heat, which is currently incompatible with the recent standpoint of global environmental protection.

[0004] From the viewpoint of recyclability, technologies have been proposed for packaging materials with a high polyethylene content and for packaging films with as simple a layer structure as possible (see, for example, Patent Documents 2 and 3). However, there are problems, such as their use being limited to light packaging due to aspects such as strength and heat resistance, and there is room for improvement in order to satisfy the various properties required for packaging materials depending on their applications. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2009-241359 [Patent Document 2] Japanese Patent Publication No. 2020-196791 [Patent Document 3] Japanese Patent Application Publication No. 2020-55157 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a laminate containing polyethylene and having recyclability, which laminate has excellent heat resistance or strength, and a package and packaged article containing the same. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a laminate comprising a substrate layer, an adhesive layer, and a sealant layer in this order, wherein the substrate layer and the sealant layer contain polyethylene, and the substrate layer has a crystallinity of 35% or more, which is the ratio of the crystalline peak area to the total peak area, measured by a parallel beam method of X-ray diffraction in the diffraction angle range of 10° to 30°.

[0008] According to another aspect of the present invention, there is provided a laminate according to the above aspect, further comprising an intermediate layer containing polyethylene and interposed between the base layer and the sealant layer.

[0009] According to yet another aspect of the present invention, there is provided a laminate according to the above aspect, wherein the intermediate layer has a crystallinity of 35% or more, which is the ratio of the crystalline peak area to the total peak area, measured by a parallel beam method of X-ray diffraction in the diffraction angle range of 10° to 30°.

[0010] According to yet another aspect of the present invention, there is provided a laminate according to the above aspect, wherein the intermediate layer has a crystallinity, which is the ratio of the crystalline peak area to the total peak area, of less than 35% when measured by a parallel beam method of X-ray diffraction in a diffraction angle range of 10° to 30°.

[0011] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, further comprising a protective layer as an outermost layer facing the sealant layer with the base layer sandwiched therebetween.

[0012] According to yet another aspect of the present invention, there is provided a laminate according to the above aspect, wherein the protective layer contains a thermosetting resin.

[0013] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the substrate layer is a biaxially stretched film.

[0014] Alternatively, according to another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the base layer is a uniaxially stretched film.

[0015] According to yet another aspect of the present invention, there is provided a laminate according to any one of the above aspects, further comprising a gas barrier layer interposed between the base layer and the sealant layer.

[0016] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the adhesive layer has gas barrier properties.

[0017] According to yet another aspect of the present invention, there is provided a laminate according to any of the above aspects, wherein the sealant layer is white.

[0018] According to yet another aspect of the present invention, there is provided a laminate according to any one of the above aspects, wherein the proportion of polyethylene in the laminate is 90% by mass or more.

[0019] According to yet another aspect of the present invention, there is provided a laminate according to any of the above aspects, which includes a first adhesive layer and a second adhesive layer as the adhesive layers, the first adhesive layer being interposed between the base layer and the intermediate layer, and the second adhesive layer being interposed between the intermediate layer and the sealant layer.

[0020] According to yet another aspect of the present invention, there is provided a package including a laminate according to any of the above aspects.

[0021] According to yet another aspect of the present invention, there is provided a package according to the above aspect, which is a stand-up pouch.

[0022] According to yet another aspect of the present invention, there is provided a packaged article including a package according to any of the above aspects and contents contained therein. [Effects of the Invention]

[0023] According to the present invention, there are provided a laminate containing polyethylene and having recyclability, which laminate has excellent heat resistance and strength, as well as a package and a packaged article containing the same. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a laminate according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a modified example of the laminate shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view schematically showing a laminate according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a laminate according to a third embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a laminate according to a fourth embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a laminate according to a fifth embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a laminate according to a sixth embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a laminate according to a seventh embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a laminate according to an eighth embodiment of the present invention. [Figure 10]FIG. 10 is a diagram schematically illustrating a packaged article according to a ninth embodiment of the present invention. [Figure 11] FIG. 11 is a diagram schematically illustrating a packaged article according to a tenth embodiment of the present invention. [Figure 12] FIG. 12 is a diagram schematically illustrating a packaged article according to an eleventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific embodiments of any of the above aspects. The following items can be incorporated into each of the above aspects, either singly or in combination.

[0026] Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited by the materials, shapes, structures, etc. of the components described below. Various modifications can be made to the technical idea of ​​the present invention within the technical scope defined by the claims.

[0027] In addition, elements having the same or similar functions are assigned the same reference numerals in the drawings referred to below, and duplicated descriptions will be omitted. Therefore, matters referred to in one embodiment can also be applied to other embodiments unless otherwise specified. Furthermore, the drawings are schematic, and the relationship between dimensions in one direction and dimensions in another direction, and the relationship between the dimensions of one member and the dimensions of another member, etc. may differ from the actual ones.

[0028] <1> First embodiment <1.1> Laminate FIG. 1 is a cross-sectional view schematically showing a laminate according to a first embodiment of the present invention. The laminate 10A1 shown in FIG. 1 includes a base layer 1, a printed layer 4, an adhesive layer 3, and a sealant layer 2 in this order.

[0029] The base layer 1 and the sealant layer 2 contain polyethylene. The laminate 10A1 preferably has a polyethylene content of 90% by mass or more. Here, the polyethylene content in the laminate refers to the proportion of the total amount of polyethylene to the total amount of resin material in each layer constituting the laminate. By ensuring that the polyethylene content is 90% by mass or more, high recyclability can be achieved.

[0030] <1.2> Base material layer The substrate layer 1 contains polyethylene. Preferably, the substrate layer 1 is made of polyethylene. The substrate layer 1 has a crystallinity of 35% or more, which is the ratio of the crystalline peak area to the total peak area, measured by the parallel beam method of X-ray diffraction in the diffraction angle range of 10° to 30°. Here, the crystallinity of the substrate layer 1 is a value obtained by the measurement method described below.

[0031] In the laminate 10A1 according to the present invention, the crystallinity of the base material layer 1 is 35% or more, which improves the heat resistance of the base material layer 1. As a result, even when the laminate 10A1 is used as a packaging material to be processed into bags in a bag-making machine, there is no need to reduce the bag-making speed, and the laminate has excellent processability.

[0032] Furthermore, when the crystallinity of the base layer 1 is 35% or more, the base layer 1 is less likely to stretch, and its printability is improved.

[0033] The polyethylene contained in the base layer 1 may be an ethylene homopolymer or a copolymer of ethylene and another monomer. When the polyethylene is a copolymer of ethylene and another monomer, the proportion of ethylene in the copolymer is, for example, 80 mol % or more.

[0034] The other monomer is, for example, an α-olefin. According to one example, the α-olefin has a carbon number in the range of 3 to 20. Such an α-olefin is, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, or 6-methyl-1-heptene.

[0035] The polyethylene may be a copolymer of ethylene and one of vinyl acetate and acrylic esters.

[0036] The substrate layer 1 is, for example, high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or very low density polyethylene (VLDPE).

[0037] Here, high density polyethylene has a density of 0.942 g / cm 3 and medium density polyethylene has a density of 0.930 g / cm 3 More than 0.942g / cm 3 Low density polyethylene has a density of 0.910 g / cm 3 More than 0.930g / cm 3 and linear low density polyethylene has a density of 0.910 g / cm 3 Over 0.930cm 3 Ultra-low density polyethylene has a density of less than 0.910 g / cm 3 is less than. The density is a value obtained by a method in accordance with JIS K7112:1999.

[0038] The polyethylene contained in the base material layer 1 may be biomass-derived polyethylene. As the biomass-derived polyethylene, for example, Green Polyethylene (manufactured by Braskem) can be used.

[0039] Alternatively, the polyethylene contained in the base layer 1 may be polyethylene recycled by mechanical recycling. Here, mechanical recycling refers to decontaminating polyethylene films by crushing collected polyethylene films, cleaning the crushed films with an alkali to remove dirt and foreign matter from the film surface, and then drying the films at high temperature and reduced pressure to diffuse contaminants remaining inside the films. Alternatively, the polyethylene contained in the base layer 1 may be polyethylene recycled by chemical recycling.

[0040] The melting point of the base layer 1 is preferably in the range of 100° C. to 140° C., and more preferably in the range of 120° C. to 140° C. The melting point is a value obtained by a method in accordance with JIS K7121-1987.

[0041] The base layer 1 may be a non-stretched film or a stretched film. The base layer 1 is preferably a stretched film. When the base layer 1 is a stretched film in addition to having a crystallinity of 35% or more, the following effects are achieved: Specifically, the heat resistance and strength are particularly excellent. Furthermore, the elongation of the base layer 1 is reduced, improving printability. In this specification, the term "film" does not include the concept of thickness.

[0042] When the base layer 1 is a stretched film, the base layer 1 may be a uniaxially stretched film or a biaxially stretched film. Using a uniaxially stretched film as the base layer 1 further improves heat resistance during bag production, i.e., sealability, which will be described later. Using a biaxially stretched film as the base layer 1 improves the drop strength of a packaged article using the laminate 10A1 as a packaging material.

[0043] Whether a stretched film is uniaxially or biaxially stretched can be determined by in-plane measurement using wide-angle X-ray diffraction, as described below. The X-ray diffraction pattern obtained by this measurement contains information about the degree of orientation of molecular chains present in the film plane.

[0044] When a polymer film is uniaxially stretched, a higher-order structure called a shish kebab structure appears. The shish kebab structure is composed of a shish structure, which is an extended chain crystal, and a kebab structure, which is a lamellar crystal. In a uniaxially stretched film, this higher-order structure is arranged with a high degree of order. Therefore, the X-ray diffraction pattern obtained by the above measurement of a uniaxially stretched film contains sharp diffraction peaks. In other words, when the above measurement is performed on a uniaxially stretched film, a clear diffraction peak appears. Note that a "clear diffraction peak" means a diffraction peak with a half-width of less than 10°.

[0045] In contrast, in the production of biaxially stretched films, the film is stretched in a specific direction and then stretched in a direction perpendicular to the first stretch. Therefore, although the above-mentioned high-order structure is generated by the first stretching, this high-order structure is disrupted by the second stretching. Therefore, when the above-mentioned measurements are performed on biaxially stretched films, the resulting X-ray diffraction pattern shows broad diffraction peaks. In other words, when the above-mentioned measurements are performed on biaxially stretched films, no clear diffraction peaks appear.

[0046] As described above, the X-ray diffraction patterns obtained by the above measurement differ between uniaxially stretched films and biaxially stretched films, and therefore, based on this, it is possible to determine whether a stretched film is a uniaxially stretched film or a biaxially stretched film.

[0047] The film can be produced by known production methods such as a casting method or an inflation method. It is also possible to use a multilayer polyethylene film obtained by co-extruding polyethylenes of different densities as the base layer 1. A stretched film can be obtained, for example, by stretching a film obtained by forming polyethylene using a T-die method or an inflation method. The base layer 1 may be a uniaxially stretched film or a biaxially stretched film.

[0048] The haze of the base layer 1 is preferably 20% or less, and more preferably 10% or less. The haze is a value obtained by a method in accordance with JIS K7136:2000.

[0049] The thickness of the base layer 1 is preferably in the range of 10 μm to 200 μm. The thickness of the base layer 1 is, for example, in the range of 10 μm to 50 μm, or in the range of 15 μm to 50 μm, or in the range of 12 μm to 35 μm. If the base layer 1 is too thin, the strength of the laminate 10A1 is likely to be reduced. On the other hand, if the base layer 1 is too thick, the processability of the laminate 10A1 is likely to be reduced.

[0050] The substrate layer 1 is preferably surface-treated, which can improve the adhesion between the substrate layer 1 and the layer adjacent to the substrate layer 1.

[0051] The method of surface treatment is not particularly limited, and examples of the surface treatment include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0052] The base layer 1 may further contain additives such as crosslinkers, antioxidants, antiblocking agents, slip agents, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0053] The proportion of polyethylene in the base layer 1 is preferably 50% by mass or more, and more preferably 80% by mass or more. According to one example, the base layer 1 is made of polyethylene. According to another example, the base layer 1 is made of polyethylene and an additive.

[0054] The substrate layer 1 may be colored, for example, white.

[0055] As described above, the base layer 1 has a crystallinity of 35% or more. The printed layer 4 is disposed on the inner surface of the base layer 1, and images such as patterns and characters displayed by the printed layer 4 can be seen with good visibility. From this viewpoint, the crystallinity of the base layer 1 is preferably 40% or more, and more preferably 50% or more. In one example, the crystallinity is in the range of 50% to 75%. Furthermore, a polyethylene-containing layer with a crystallinity of 35% or more also has excellent puncture strength, as will be described below. From this viewpoint, the crystallinity of the base layer 1 is preferably 40% or more, and more preferably 50% or more.

[0056] Polyethylene is a crystalline polymer, so it has both crystalline and amorphous parts. Polyethylene with a high degree of crystallinity has a high proportion of crystalline parts. This crystalline part controls the elastic part of the resin's viscoelastic behavior, so a high degree of crystallinity improves the rigidity of the film.

[0057] Due to the influence of this viscoelastic behavior, films with high crystallinity also experience greater strain due to plastic deformation of the resin. As a result, the resin deformation is suppressed in response to strain generated by an instantaneous impact applied to the film, making it less likely to break. For this reason, laminate 10A1 having a base material 1 containing polyethylene and having a crystallinity of 35% or more has excellent resistance to instantaneous impact, and packaged articles using laminate 10A1 as a packaging material are less likely to break (break) when dropped. In other words, it has excellent resistance to bag breakage.

[0058] The crystallinity of the base layer 1 can be adjusted by controlling the degree of stretching of the polyethylene film used for the base layer 1 and the thermal history during or after film production. For example, slow cooling after film formation increases the crystallinity, while rapid cooling decreases it. It is also possible to improve the crystallinity by adding additives such as a crystal nucleating agent.

[0059] <Method for measuring crystallinity> The crystallinity of the substrate layer 1 is measured by X-ray diffraction using a parallel beam method. An example of a method for measuring the crystallinity will be described below.

[0060] First, an X-ray diffraction pattern of the base layer 1 is obtained by out-of-plane measurement using a wide-angle X-ray diffractometer manufactured by Rigaku Corporation, with 2θ / θ scanning over a diffraction angle range of 10° to 30°. The characteristic X-ray, CuKα, is used, and the X-ray is collimated by a multilayer mirror before being incident on the base layer 1. A scintillation detector equipped with a flat collimator is used as the light-receiving unit.

[0061] From the obtained X-ray diffraction pattern, the peak area of ​​the crystalline component and the halo pattern area of ​​the amorphous component are determined, and the ratio of the peak area of ​​the crystalline component to the total area is calculated as the degree of crystallinity. When the base layer 1 has a plurality of layers, the crystallinity of one of the outermost surfaces of the base layer 1 is measured.

[0062] When the base layer 1 is a polyethylene film, scanning at a diffraction angle range of 10° to 30° reveals two sharp crystalline component peaks corresponding to the (110) and (200) planes, as well as a broad halo pattern of amorphous components. These are then analyzed separately, and the areas of the crystalline component peaks and the halo pattern of the amorphous component are calculated, allowing the degree of crystallinity to be calculated using the following formula (1):

[0063] Crystallinity = crystalline component peak area / (crystalline component peak area + amorphous component halo pattern area) (1) Another known X-ray diffraction method besides the parallel beam method is the focusing method, but with the focusing method, measurement results can be easily affected by peak broadening due to misalignment of the measurement surface when using samples with uneven surfaces, such as resin films.In contrast, with the parallel beam method, misalignment of the measurement surface has little effect on measurement results, even when using samples with uneven surfaces.

[0064] On the other hand, the base layer 1 is preferably uniaxially or biaxially stretched, and as described above, the in-plane method using X-ray diffraction can be used to distinguish between these. This in-plane method involves fixing the X-ray incident angle θ and the angle 2θ at which the diffracted X-rays are detected by a detector to the angles θ and 2θ at which a diffraction peak corresponding to a specific crystal plane is detected in the out-of-plane method, for example, the diffraction peak corresponding to the (110) plane of a polyethylene film, and then scanning the film to be measured in the in-plane direction to obtain a diffraction pattern.

[0065] In-plane measurements of uniaxially stretched films in the machine direction (MD) yield a diffraction pattern with a sharp diffraction peak corresponding to the (110) plane at an angle 2θ of approximately ±90° (where MD is defined as 0°). On the other hand, in the case of biaxially stretched films, the high-order structure obtained by uniaxial stretching is disrupted by the second stretching, resulting in a decrease in anisotropy, making it impossible to obtain a diffraction pattern with a sharp diffraction peak corresponding to the (110) plane. Therefore, in-plane measurements can be used to distinguish uniaxially stretched films from biaxially stretched films.

[0066] <1.3> Sealant layer The sealant layer 2 faces the base layer 1. The sealant layer 2 contains polyethylene. Preferably, the sealant layer 2 is made of polyethylene. For example, the polyethylenes mentioned above for the polyethylene contained in the base layer 1 can be used. The sealant layer 2 is preferably low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very-high-density polyethylene (VLDPE), and more preferably linear low-density polyethylene.

[0067] From the viewpoint of environmental load, the polyethylene is preferably biomass-derived polyethylene or recycled polyethylene.

[0068] The sealant layer 2 may further contain the additives described above. The proportion of polyethylene in the sealant layer 2 is preferably 50% by mass or more, and more preferably 80% by mass or more. In one example, the sealant layer 2 is made of polyethylene. In another example, the sealant layer 2 is made of polyethylene and an additive.

[0069] The sealant layer 2 may be transparent or opaque. In the latter case, the sealant layer 2 is preferably white. When the laminate 10A1 has a transparent sealant layer 2 and is used in a package, the contents are easily visible. When the laminate 10A1 has an opaque sealant layer 2 and is used in a package, the contents do not interfere with the visibility of the image displayed by the printing layer 4. In particular, a white sealant layer 2 improves the visibility of the image displayed by the printing layer 4.

[0070] The thickness of the sealant layer 2 can be appropriately set in consideration of the shape of the packaging bag to be manufactured, the mass of the contents to be contained, etc., and can be, for example, 30 to 150 μm.

[0071] The sealant layer 2 is, for example, an unstretched polyethylene resin film or a layer formed by melt-extrusion of polyethylene.

[0072] <1.4>Printing layer The printed layer 4 is provided on the surface of the base layer 1 facing the sealant layer 2, i.e., on the back surface of the base layer 1. The position at which the printed layer 4 is provided is not limited. That is, the printed layer 4 may be provided on the surface of the base layer 1, or may be provided at any position between the base layer 1 and the sealant layer 2. For example, if the laminate 10A1 further includes an intermediate layer described below, the printed layer 4 may be provided on either side of the intermediate layer. Furthermore, the laminate 10A1 may include multiple printed layers. The printed layer 4 may be omitted.

[0073] The printing ink used for the printed layer 4 is not particularly limited as long as it has adhesion to polyethylene. The printed layer 4 is composed of inks containing additives such as various pigments, extender pigments, plasticizers, desiccants, and stabilizers added to conventionally used ink binder resins, such as urethane-based, acrylic-based, nitrocellulose-based, rubber-based, and vinyl chloride-based inks. Biomass-derived inks are preferred. Examples of printing methods include well-known printing methods such as offset printing, gravure printing, flexographic printing, and silkscreen printing, as well as well-known coating methods such as roll coating, knife-edge coating, and gravure coating. Light-blocking inks are also preferred. Examples of inks include white, black, silver, and sepia inks.

[0074] <1.5>Adhesive layer The adhesive layer 3 bonds the base material layer 1, on which the printing layer 4 is provided, to the sealant layer 2. The adhesive layer 3 contains at least one type of adhesive. The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may also be a solventless adhesive or a solvent-based adhesive.

[0075] Examples of adhesives include epoxy adhesives such as polyether adhesives, polyester adhesives, silicone adhesives, and polyamine adhesives, as well as urethane adhesives, rubber adhesives, vinyl adhesives, silicone adhesives, epoxy adhesives, phenolic adhesives, and olefin adhesives. Adhesives containing biomass components can also be used. The adhesive is preferably a polyamine adhesive or urethane adhesive with gas barrier properties. Specific examples of gas barrier adhesives include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation.

[0076] The adhesive layer 3 may be a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound. Such an adhesive layer 3 can further improve the oxygen barrier property and water vapor barrier property of the laminate 10A1.

[0077] The thickness of the adhesive layer 3 is preferably in the range of 0.1 μm to 20 μm, more preferably in the range of 0.5 μm to 10 μm, and even more preferably in the range of 1 to 5 μm.

[0078] The adhesive layer 3 can be formed by applying and drying on the sealant layer 2 using a conventionally known method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fountain coating, and transfer roll coating.

[0079] <1.6>Effects The above-described laminate 10A1 has excellent heat resistance and recyclability, which will be explained below.

[0080] The manufacture of packaging bags generally involves a process of bringing sealant layers of a laminate into contact with each other, clamping the contact area with a jig, and applying pressure and heat to the contact area to thermally weld (heat seal) the contact area. The jig of the heat sealing machine is heated to a high temperature, and the surface of the base layer that directly contacts the jig is exposed to high temperatures. As a result, when polyethylene, which has poor heat resistance, is used for the base layer, the surface of the base layer may be affected by heat, causing problems such as adhesion to the jig. Therefore, conventional laminates using polyethylene for the base layer have a narrow range of appropriate bag-making temperatures, which has led to poor productivity.

[0081] The inventors measured the crystallinity of various polyethylenes and found that when the crystallinity of base layer 1 is 35% or higher, base layer 1 exhibits excellent heat resistance, and therefore laminate 10A1 also exhibits excellent heat resistance, achieving particularly good heat-sealing suitability. Laminate 10A1 uses polyethylene, which is generally considered to have poor heat resistance, as base layer 1. However, by setting the crystallinity of base layer 1 to 35% or higher, the temperature range for heat sealing performed for bag formation is expanded, allowing packages to be produced without a decrease in productivity or poor appearance due to shrinkage of the sealed portion.

[0082] The laminate 10A1 has such excellent heat resistance, and since the crystallinity of the base layer 1 is used as an indicator, the surface characteristics of the laminate 10A1 can be easily measured and understood, making it easy to stabilize its quality as a packaging material.

[0083] Furthermore, since the laminate 10A1 includes the base layer 1 and the seat heel layer, each of which is primarily composed of polyethylene, it is easy to achieve a polyethylene ratio of 90% by mass or more, which makes the laminate 10A1 highly recyclable.

[0084] <1.7> Variations The laminate 10A1 can be modified in various ways. Fig. 2 is a cross-sectional view schematically showing a modified example of the laminate shown in Fig. 1. The laminate 10A2 shown in Fig. 2 is similar to the laminate 10A1 except that it further includes an inorganic compound layer 5 interposed between the base material layer 1 and the printed layer 4. The inorganic compound layer 5 is a thin film made of an inorganic compound, for example, an inorganic oxide such as aluminum oxide or silicon oxide, and functions as a gas barrier layer that suppresses the transmission of oxygen and water vapor.

[0085] <Inorganic compound layer> The inorganic compound layer 5 may be formed by coating or by vapor deposition of an inorganic compound.

[0086] Examples of inorganic compounds contained in the inorganic compound layer 5 include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. The inorganic compound layer 5 is preferably a vapor-deposited film made of a metal oxide. From the viewpoints of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of cost, the metal oxide is selected from aluminum oxide and silicon oxide. Furthermore, from the viewpoint of excellent tensile elongation during processing, it is more preferable to use silicon oxide as the metal oxide. By making the inorganic compound layer 5 a vapor-deposited film made of a metal oxide, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate 10A2.

[0087] A vapor-deposited film made of a metal oxide has transparency, and therefore has the advantage that, compared to a vapor-deposited film made of a metal, it is less likely to cause a user who holds a packaging material made of a laminate to mistakenly believe that a metal foil is used.

[0088] The thickness of the vapor-deposited film made of aluminum oxide is preferably 5 nm or more and 30 nm or less. A film thickness of 5 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 30 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 30 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the thickness of the vapor-deposited film made of aluminum oxide is more preferably 7 nm or more and 15 nm or less.

[0089] The thickness of the vapor-deposited film made of silicon oxide is preferably 10 nm or more and 50 nm or less. A film thickness of 10 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 50 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 50 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the film thickness of the vapor-deposited film made of silicon oxide is more preferably 20 nm or more and 40 nm or less.

[0090] The inorganic compound layer 5 can be formed by, for example, vacuum film formation. In vacuum film formation, physical vapor deposition or chemical vapor deposition can be used. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD (Chemical Vapor Deposition), plasma CVD, and photo CVD.

[0091] In the vacuum film formation, resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, induction heating vacuum evaporation, sputtering, reactive sputtering, dual magnetron sputtering, plasma enhanced chemical vapor deposition (PECVD), and the like are particularly preferably used. However, in terms of productivity, vacuum evaporation is currently the most superior. As a heating means for vacuum evaporation, it is preferable to use any of the electron beam heating method, resistance heating method, and induction heating method.

[0092] <Anchor coat layer> As will be described in the second embodiment, the laminate 10A2 may further include an anchor coat layer (not shown). The anchor coat layer can be formed using a known anchor coat agent on the surface of the base layer 1 on which the inorganic compound layer 5 is to be formed. This can improve the adhesion of the inorganic compound layer 5 made of metal oxide. Examples of anchor coat agents include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoints of heat resistance and interlayer adhesive strength, polyester-based polyurethane resins are preferred as the anchor coat agent.

[0093] <Coating layer> Furthermore, as will be described in the second embodiment, the laminate 10A2 may further include a coating layer (not shown) between the inorganic compound layer 5 and the printed layer 4. The combination of the inorganic compound layer 5 and the coating layer can also function as a gas barrier layer. Hereinafter, the inorganic compound layer 5 may be referred to as the gas barrier layer, and the combination of the inorganic compound layer 5 and the coating layer may be referred to as the gas barrier layer.

[0094] The laminate 10A2 also has excellent heat resistance. Furthermore, since the inorganic compound layer 5 is substantially transparent, even if the inorganic compound layer 5 is provided between the base material layer 1 and the printed layer 4, the image displayed by the printed layer 4 can be seen from the surface side. Furthermore, the laminate 10A2 also has excellent recyclability.

[0095] Furthermore, in order to impart light-blocking properties to the laminates 10A1 and 10A2, a metal vapor-deposited layer may be provided between the base layer 1 and the sealant layer 2. When the laminate further includes an intermediate layer (described later), a metal vapor-deposited layer may be provided on either side of the intermediate layer. An example of the metal vapor-deposited layer is an aluminum vapor-deposited layer.

[0096] As already mentioned, the sealant layer 2 may be opaque, but the base layer 1 may also be opaque. For example, the base layer 1 may be white. When the laminate further includes an intermediate layer, which will be described later, the intermediate layer may also be opaque. For example, the intermediate layer may be white.

[0097] <2> Second embodiment <2.1> Laminate FIG. 3 is a cross-sectional view schematically showing a laminate according to a second embodiment of the present invention. The laminate 10B shown in FIG. 3 includes a protective layer 6, a base material layer 1, a gas barrier layer 5, a printed layer 4, an adhesive layer 3, and a sealant layer 2, in this order. The gas barrier layer 5 included in the laminate 10B is composed of an inorganic compound layer, or an inorganic compound layer and a coating layer. The laminate 10B is similar to the laminate 10A1 except that it further includes a protective layer 6 provided on the surface of the base material layer 1, and a gas barrier layer 5 interposed between the base material layer 1 and the printed layer 4. The base material layer 1, printed layer 4, adhesive layer 3, and sealant layer 2 included in the laminate 10B can be those described in the first embodiment.

[0098] <2.2>Protective layer The laminate 10B includes a protective layer 6 as the outermost layer. The protective layer 6 contains a thermosetting resin. The thermosetting resin is not particularly limited as long as it has heat resistance, and examples thereof include polyurethane resin, polyester resin, polyamide resin, polyamideimide resin, acrylic resin, epoxy resin, and water-soluble polymer. The protective layer 6 may contain one type of thermosetting resin or two or more types of thermosetting resin.

[0099] In one embodiment, the protective layer 6 preferably contains a water-soluble polymer, and is preferably an organic-inorganic composite layer that further contains an organometallic compound.

[0100] Examples of water-soluble polymers include polyvinyl alcohols, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyols. In one embodiment, the protective layer 6 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that may be contained in a coating layer serving as the gas barrier layer 5 described below.

[0101] The protective layer 6 preferably contains at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a metal alkoxide or its hydrolyzate as an organometallic compound. Examples of metal alkoxides include alkoxides represented by the general formula M(OR), such as tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3]. n Examples include those represented by the following formula:

[0102] Furthermore, the protective layer 6 preferably further contains, as the organometallic compound, at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0103] In one embodiment, the protective layer 6 can be formed using a coating liquid for forming a coating layer as the gas barrier layer 5, which will be described later. When the laminate 10B includes an inorganic compound layer and a coating layer as the gas barrier layer 5, the protective layer 6 may be a layer formed using the same coating liquid as the coating liquid used to form the coating layer.

[0104] The protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. The laminate 10B has the protective layer 6, which has excellent heat resistance, as the outermost layer, thereby ensuring heat sealability and productivity even though the base material is polyethylene resin, which has poor heat resistance.

[0105] The thickness of the protective layer 6 is preferably within a range of 0.3 μm to 3 μm. If the protective layer 6 is too thin, it tends to be difficult to achieve high heat resistance. If the protective layer 6 is too thick, it tends to be difficult to sufficiently dry the cured resin film during the manufacturing process of the laminate 10B.

[0106] <2.3> Gas barrier layer The gas barrier layer 5 improves, for example, the oxygen barrier property and water vapor barrier property of the laminate 10B. The gas barrier layer 5 is composed of an inorganic compound layer, or an inorganic compound layer and a coating layer. When the gas barrier layer 5 is composed of an inorganic compound layer and a coating layer, the inorganic compound layer and the coating layer are preferably laminated in this order from the side of the base layer 1. The gas barrier layer 5 may be formed by coating, or may be formed by vapor-depositing an inorganic compound. The inorganic compound layer is the same as the inorganic compound layer described in the modified example of the first embodiment.

[0107] The coating layer can be formed, for example, by coating. In this case, a coating liquid containing a resin such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, or epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may also be added to the coating liquid.

[0108] The coating layer may be an organic-inorganic composite layer containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolyzate of a metal alkoxide, and a water-soluble polymer. This organic-inorganic composite layer may further contain at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolyzate of a silane coupling agent.

[0109] Examples of metal alkoxides and their hydrolysates contained in the organic-inorganic composite layer include compounds represented by the general formula M(OR), such as tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3]. n and hydrolysates thereof. One of these may be contained alone, or two or more may be contained in combination.

[0110] The total content of the metal alkoxide, its hydrolysate, or their reaction products in the coating liquid used to form the organic-inorganic composite layer may be, for example, 40% by mass or more, 50% by mass or more, or 65% by mass or more, from the viewpoint of oxygen barrier property. The total content of the metal alkoxide, its hydrolysate, or their reaction products in the coating liquid may be, for example, 70% by mass or less.

[0111] The water-soluble polymer contained in the organic-inorganic composite layer is not particularly limited, and examples thereof include polyvinyl alcohol-based polymers, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving the oxygen gas barrier property, the water-soluble polymer preferably contains a polyvinyl alcohol-based water-soluble polymer. The number-average molecular weight of the water-soluble polymer is, for example, 40,000 to 180,000.

[0112] The polyvinyl alcohol-based water-soluble polymer contained in the organic-inorganic composite layer can be obtained, for example, by saponifying (including partial saponification) polyvinyl acetate. This water-soluble polymer may have several tens of percent or only a few percent of acetate groups remaining.

[0113] The content of the water-soluble polymer in the coating liquid used to form the organic-inorganic composite layer may be, for example, 15% by mass or more, or 20% by mass or more, from the viewpoint of oxygen barrier properties, and may be, for example, 50% by mass or less, or 45% by mass or less, from the viewpoint of oxygen barrier properties.

[0114] Silane coupling agents used in the organic-inorganic composite layer include silane coupling agents having an organic functional group. Examples of such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. Silane coupling agents selected from these, their hydrolyzates, and their reaction products can be used alone or in combination of two or more.

[0115] It is preferable to use a silane coupling agent having an epoxy group as an organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The silane coupling agent having an epoxy group may have an organic functional group other than the epoxy group, such as a vinyl group, an amino group, a methacryl group, or a ureyl group. One of the silane coupling agents selected from these, their hydrolyzates, and their reaction products may be used alone or in combination of two or more.

[0116] A silane coupling agent having an organic functional group, its hydrolyzate, or a reaction product thereof can further improve the oxygen barrier property of the coating layer and the adhesion to an adjacent layer through the interaction between the organic functional group and the hydroxyl group of the water-soluble polymer. In particular, when the silane coupling agent, its hydrolyzate, or a reaction product thereof has an epoxy group and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction between the epoxy group and the hydroxyl group of the PVA can further improve the oxygen barrier property and the adhesion to an adjacent layer.

[0117] The total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid used to form the organic-inorganic composite layer may be, for example, 1% by mass or more, or 2% by mass or more, from the viewpoint of oxygen barrier properties. Also, the total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid may be, for example, 15% by mass or less, or 12% by mass or less, from the viewpoint of oxygen barrier properties.

[0118] The thickness of the coating layer is preferably 50 nm to 1000 nm, more preferably 100 nm to 500 nm. When the thickness of the gas barrier coating layer is 50 nm or more, more sufficient gas barrier properties tend to be obtained, and when it is 1000 nm or less, sufficient flexibility tends to be maintained.

[0119] The gas barrier layer 5 is preferably subjected to the above-mentioned surface treatment, which can improve the adhesion between the gas barrier layer 5 and the adjacent layer. The gas barrier layer 5 may be made of a nanocomposite material.

[0120] In laminate 10B, printed layer 4 is interposed between gas barrier layer 5 and adhesive layer 3, but may be provided anywhere between protective layer 6 and sealant layer 2. Because base layer 1 is transparent, the pattern displayed by printed layer 4 can be clearly seen when laminate 10B is observed from the protective layer 6 side, regardless of the location of printed layer 4 between base layer 1 and sealant layer 2, for example.

[0121] <Anchor coat layer> The laminate 10B may further include an anchor coating layer (not shown) on one of the main surfaces of the base layer 1 that faces the gas barrier layer 5. This can improve the adhesion of the gas barrier layer 5. Examples of anchor coating agents include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoints of heat resistance and interlayer adhesive strength, polyester-based polyurethane resins are preferred as the anchor coating agent.

[0122] The proportion of polyethylene in the laminate 10B is, for example, 90% by mass or more, which makes the laminate 10B a highly recyclable mono-material.

[0123] <2.4> Effects Like the laminate 10A1, the laminate 10B has a base layer 1 that contains polyethylene and has a crystallinity within the above range. Therefore, like the laminate 10A1, the laminate 10B has excellent heat resistance.

[0124] Furthermore, laminate 10B includes protective layer 6 as the outermost layer. As described above, protective layer 6 reduces thermal damage to the surface of the laminate during heat sealing. Therefore, laminate 10B can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for laminate 10B, the temperature range for heat sealing performed for bag formation is expanded, making it even less likely that reduced productivity or poor appearance due to shrinkage of the sealed portion will occur.

[0125] Furthermore, since the above-mentioned gas barrier layer 5, i.e., the inorganic compound layer and the coating layer, are substantially transparent, even if the gas barrier layer 5 is provided between the base material layer 1 and the printing layer 4, the image displayed by the printing layer 4 can be seen from the surface side. That is, the laminate 10B has excellent heat resistance and recyclability.

[0126] <3> Third embodiment <3.1> Laminate FIG. 4 is a cross-sectional view schematically showing a laminate according to a third embodiment of the present invention. The laminate 10C shown in FIG. 4 includes a protective layer 6, a base layer 1, an inorganic compound layer 5, a coating layer 7, a printed layer 4, an adhesive layer 3, and a sealant layer 2, in this order. The laminate 10C has a polyethylene content of 90% by mass or more. The laminate 10C has a layer structure similar to that of the laminate 10B according to the second embodiment, including an inorganic compound layer and a coating layer from the base layer 1 side as the gas barrier layer 5. The protective layer 6, base layer 1, inorganic compound layer 5, coating layer 7, printed layer 4, adhesive layer 3, and sealant layer 2 included in the laminate 10C can be those described in the second embodiment. In the laminate 10C, the inorganic compound layer 5, coating layer 7, and printed layer 4 can be omitted.

[0127] <Anchor coat layer> Like the laminate 10B according to the second embodiment, the laminate 10C may further include an anchor coating layer (not shown) on one of the main surfaces of the base layer 1 that faces the inorganic compound layer 5. This can improve the adhesion of the inorganic compound layer 5. Examples of anchor coating agents include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoints of heat resistance and interlayer adhesive strength, polyester-based polyurethane resins are preferred as the anchor coating agent.

[0128] <3.3> Effects The laminate 10C has the same layer structure as the laminate 10B, and therefore exhibits the same effects as the laminate 10B.

[0129] <4> Fourth embodiment <4.1> Laminate FIG. 5 is a cross-sectional view schematically showing a laminate according to a fourth embodiment of the present invention. The laminate 10D shown in FIG. 5 includes a base layer 1, a first adhesive layer 3A, a gas barrier layer 5, an intermediate layer 8, a printed layer 4, a second adhesive layer 3B, and a sealant layer 2, in this order. The laminate 10D is similar to the laminate 10B except for the following points. That is, the laminate 10D further includes an intermediate layer 8. Furthermore, the laminate 10D includes a first adhesive layer 3A and a second adhesive layer 3B instead of the adhesive layer 3. The base layer 1, printed layer 4, and sealant layer 2 included in the laminate 10D can be those described in the first embodiment.

[0130] <4.2> Gas barrier layer The gas barrier layer 5 improves, for example, the oxygen barrier property and water vapor barrier property of the laminate 10D. The gas barrier layer 5 is, for example, a metal layer, an inorganic oxide layer, a resin-containing layer, or a combination of two or more thereof. When microwave heating using a microwave oven is expected, the gas barrier layer 5 is preferably an inorganic oxide layer, a resin-containing layer, or a combination thereof.

[0131] The gas barrier layer 5 may be formed by coating, by melt molding, or by vapor deposition of an inorganic oxide. Alternatively, the gas barrier layer 5 may be a metal foil such as an aluminum foil, or may be vapor deposited with a metal such as aluminum.

[0132] Examples of inorganic oxides that can be used include silicon oxide, boron oxide, and metal oxides such as aluminum oxide, magnesium oxide, calcium oxide, potassium oxide, tin oxide, sodium oxide, titanium oxide, lead oxide, zirconium oxide, and yttrium oxide.

[0133] The resin-containing layer can be formed, for example, by coating. In this case, a coating liquid containing a resin such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, or epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may also be added to this coating liquid.

[0134] When the resin-containing layer is formed by melt molding, extrusion molding techniques such as T-die and inflation can be used. In melt molding, for example, the resin or a mixture of the resin and additives is heated and melted, and a film or sheet to be used as the gas barrier layer 5 is obtained by T-die or inflation. This film or sheet is then bonded to the intermediate layer 8.

[0135] The thickness of the gas barrier layer 5 is preferably in the range of 1 nm to 200 nm, for example, if it is an inorganic oxide layer. A thickness of 1 nm or more provides excellent oxygen barrier properties and water vapor barrier properties. A thickness of 200 nm or less can keep production costs low, and cracks caused by external forces such as bending or pulling are less likely to occur, thereby preventing deterioration of barrier properties. Furthermore, for example, if it is a resin-containing layer, the thickness is preferably in the range of 0.1 μm to 10 μm, and more preferably in the range of 0.2 μm to 5 μm. A thickness of 0.2 μm or more provides excellent oxygen barrier properties and water vapor barrier properties. A thickness of 10 μm or less can keep production costs low.

[0136] The gas barrier layer 5 is preferably subjected to the above-mentioned surface treatment, which can improve the adhesion between the gas barrier layer 5 and the adjacent layer. The gas barrier layer 5 may be made of a nanocomposite material.

[0137] <4.3> Middle class The intermediate layer 8 contains polyethylene. As the polyethylene, for example, the polyethylene contained in the base layer 1 described above can be used.

[0138] The polyethylene contained in the intermediate layer 8 may be the same as or different from the polyethylene contained in the base layer 1. Furthermore, the intermediate layer 8 may further contain the additives described above.

[0139] The proportion of polyethylene in the mid layer 8 is preferably 50% by mass or more, and more preferably 80% by mass or more. According to one example, the mid layer 8 is made of polyethylene. According to another example, the mid layer 8 is made of polyethylene and an additive.

[0140] The intermediate layer 8 has a crystallinity of 35% or more. The intermediate layer 8 preferably has a crystallinity of 40% or more, and more preferably has a crystallinity of 50% or more. In one example, the crystallinity of the intermediate layer 8 is in the range of 50% to 75%.

[0141] The intermediate layer 8 having a crystallinity of 35% or more increases the strength of the laminate 10D, particularly its puncture resistance. Therefore, the laminate 10D has excellent strength, particularly excellent puncture resistance. Laminates with a high proportion of polyethylene are weaker than other laminates and are therefore frequently folded when used as packaging materials. Frequent folding increases the likelihood of pinholes occurring, but the laminate 10D, which has excellent puncture resistance, is less likely to develop pinholes. From this perspective, the intermediate layer 8 having a crystallinity of 35% or more is preferably a stretched film, and it is more preferable that both the base layer 1 and the intermediate layer 8 are stretched films. In this case, the stretched film constituting the intermediate layer 8 may be the same as or different from the stretched film constituting the base layer 1.

[0142] The melting point of the intermediate layer 8 is preferably in the range of 100°C to 140°C, and more preferably in the range of 120°C to 140°C.

[0143] The thickness of the intermediate layer 8 is preferably in the range of 10 μm to 200 μm, and more preferably in the range of 15 μm to 50 μm.

[0144] The intermediate layer 8 may be colored, for example white.

[0145] The intermediate layer 8 can be produced by known methods such as a casting method or an inflation method. It is also possible to use a multilayer polyethylene film obtained by co-extruding polyethylenes of different densities as the intermediate layer 8. A stretched film can be obtained, for example, by stretching a film obtained by forming polyethylene into a film by a T-die method or an inflation method.

[0146] In this embodiment, an intermediate layer having a crystallinity of less than 35% may be used. By using an intermediate layer having a crystallinity of less than 35%, the strength of the laminate 10D, particularly its drop strength, can be improved. An intermediate layer having a crystallinity of less than 35% is preferably a non-stretched film.

[0147] <4.4>Adhesive layer The adhesives for forming the first adhesive layer 3A and the second adhesive layer 3B may be the same or different, and the adhesives for forming the first adhesive layer 3A and the second adhesive layer 3B include at least one type of adhesive.

[0148] The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may also be a solventless adhesive or a solvent-based adhesive.

[0149] Examples of adhesives include epoxy adhesives such as polyether adhesives, polyester adhesives, silicone adhesives, and polyamine adhesives, as well as urethane adhesives, rubber adhesives, vinyl adhesives, silicone adhesives, epoxy adhesives, phenolic adhesives, and olefin adhesives. Adhesives containing biomass components can also be used. The adhesive is preferably a polyamine adhesive or urethane adhesive having gas barrier properties.

[0150] The first adhesive layer 3A and the second adhesive layer 3B may be a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound. Such first adhesive layer 3A and second adhesive layer 3B provide the laminate 10D with excellent oxygen barrier properties and water vapor barrier properties.

[0151] The thickness of the first adhesive layer 3A and the second adhesive layer 3B is preferably in the range of 0.1 μm to 20 μm, more preferably in the range of 0.5 μm to 10 μm, and even more preferably in the range of 1 to 5 μm.

[0152] The first adhesive layer 3A and the second adhesive layer 3B can be formed by applying and drying on the base material layer 1 using a conventionally known method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fountain coating, and transfer roll coating.

[0153] In FIG. 5, the laminate 10D includes a gas barrier layer 5 between the first adhesive layer 3A and the intermediate layer 8, but the laminate 10D may also include a gas barrier layer 5 between the intermediate layer 8 and the second adhesive layer 3B.

[0154] 5, the printed layer 4 is provided between the intermediate layer 8 and the second adhesive layer 3B, but the printed layer 4 may be provided anywhere between the base layer 1 and the sealant layer 2. The printed layer 4 is preferably provided between the first adhesive layer 3A and the base layer 1. In this case, when the laminate 10B is observed from the base layer 1 side, the pattern displayed by the printed layer 4 is easily seen clearly.

[0155] An anchor coat layer may be formed on the main surface of the base layer 1 that faces the first adhesive layer 3A. The gas barrier layer 5 and the printed layer 4 may be omitted.

[0156] The proportion of polyethylene in the laminate 10D is, for example, 90% by mass or more, which makes the laminate 10D a highly recyclable mono-material.

[0157] <4.5> Effects Like the laminate 10A1, the laminate 10D described above has a base layer 1 that contains polyethylene and has a crystallinity within the above range. Therefore, like the laminate 10A1, the laminate 10D has excellent heat resistance.

[0158] Furthermore, the laminate 10D includes an intermediate layer 8 having a crystallinity within the above range. This intermediate layer 8 increases the strength, particularly the puncture strength, of the laminate 10D. Therefore, the laminate 10D has excellent strength, particularly the puncture strength.

[0159] Furthermore, since the base layer 1, the intermediate layer 8, and the sealant layer 2 of the laminate 10D all contain polyethylene, this laminate has excellent recyclability.

[0160] Furthermore, as described above, laminates with a high proportion of polyethylene are weaker than other laminates, and therefore are frequently folded when used as packaging materials. Frequent folding increases the likelihood of pinholes occurring, but laminate 10D, which has excellent puncture resistance, is less likely to develop pinholes.

[0161] Here, the "puncture strength" of the laminate 10D is a value obtained by piercing the laminate 10D from the base layer 1 side using the method specified in JIS Z1707:2019 "General Rules for Food Packaging Plastic Films." Specifically, a needle with a diameter of 1 mm and a semicircular tip is pierced into the laminate 10D from the base layer 1 side at a speed of 50 mm / min, and the maximum force required for the needle to penetrate is measured. This measurement is performed multiple times, and the arithmetic average of the maximum forces is obtained as the puncture strength.

[0162] <5> Fifth embodiment <5.1> Laminate FIG. 6 is a cross-sectional view schematically showing a laminate according to a fifth embodiment of the present invention. The laminate 10E shown in FIG. 6 includes a protective layer 6, a substrate layer 1, a printed layer 4, a first adhesive layer 3A, an intermediate layer 8, a gas barrier layer 5, a second adhesive layer 3B, and a sealant layer 2, in this order. The laminate 10E is similar to the laminate 10D except for the following points. That is, the laminate 10E further includes a protective layer 6. In the laminate 10E, the inorganic compound layer 5 is interposed between the second adhesive layer 3B and the intermediate layer 8. In the laminate 10E, the printed layer 4 is interposed between the substrate layer 1 and the first adhesive layer 3A. The substrate layer 1, printed layer 4, first adhesive layer 3A, intermediate layer 8, second adhesive layer 3B, and sealant layer 2 included in the laminate 10E can be those described in the fourth embodiment.

[0163] <5.2>Protective layer The protective layer 6 contains a thermosetting resin. The thermosetting resin is not particularly limited as long as it has heat resistance, and examples thereof include polyurethane resin, polyester resin, polyamide resin, polyamideimide resin, acrylic resin, epoxy resin, and water-soluble polymer. The protective layer 6 may contain one type of thermosetting resin or two or more types of thermosetting resin.

[0164] In one embodiment, the protective layer 6 is preferably an organic-inorganic composite layer containing a water-soluble polymer and an organometallic compound.

[0165] Examples of water-soluble polymers include polyvinyl alcohols, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyols. In one embodiment, the protective layer 6 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that may be contained in a coating layer serving as the gas barrier layer 5 described below.

[0166] The protective layer 6 preferably contains at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a metal alkoxide or its hydrolyzate as an organometallic compound. Examples of metal alkoxides include alkoxides represented by the general formula M(OR), such as tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3]. n Examples include those represented by the following formula:

[0167] Furthermore, the protective layer 6 preferably further contains, as the organometallic compound, at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0168] In one embodiment, the protective layer 6 can be formed using a coating liquid for forming a coating layer as the gas barrier layer 5, which will be described later. When the laminate 10E includes an inorganic compound layer and a coating layer as the gas barrier layer 5, the protective layer 6 may be a layer formed using the same coating liquid as the coating liquid used to form the coating layer.

[0169] The laminate 10E has the protective layer 6, which has excellent heat resistance, as the outermost layer, and therefore ensures heat sealability and productivity even though the base material is polyethylene resin, which has poor heat resistance.

[0170] The thickness of the protective layer 6 is preferably within a range of 0.3 μm to 3 μm. If the protective layer 6 is too thin, it tends to be difficult to achieve high heat resistance. If the protective layer 6 is too thick, it tends to be difficult to sufficiently dry the cured resin film during the manufacturing process of the laminate 10E.

[0171] <5.3> Gas barrier layer The gas barrier layer 5 improves, for example, the oxygen barrier property and water vapor barrier property of the laminate 10E. The gas barrier layer 5 is composed of an inorganic compound layer or an inorganic compound layer and a coating layer. When the gas barrier layer 5 is composed of an inorganic compound layer and a coating layer, the inorganic compound layer and the coating layer are preferably laminated in this order from the intermediate layer 8 side.

[0172] The gas barrier layer 5 may be formed by coating or by vapor deposition of an inorganic compound.

[0173] Examples of inorganic compounds contained in the inorganic compound layer include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. The inorganic compound layer is preferably a vapor-deposited film made of a metal oxide. From the viewpoints of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of cost, the metal oxide is selected from aluminum oxide and silicon oxide. Furthermore, from the viewpoint of excellent tensile elongation during processing, it is more preferable to use silicon oxide as the metal oxide. By using a vapor-deposited film made of a metal oxide as the inorganic compound layer contained in the gas barrier layer 5, high barrier properties can be obtained with an extremely thin layer that does not affect the recyclability of the laminate 10E.

[0174] A vapor-deposited film made of a metal oxide has transparency, and therefore has the advantage that, compared to a vapor-deposited film made of a metal, it is less likely to cause a user who holds a packaging material made of a laminate to mistakenly believe that a metal foil is used.

[0175] The thickness of the vapor-deposited film made of aluminum oxide is preferably 5 nm or more and 30 nm or less. A film thickness of 5 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 30 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 30 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the thickness of the vapor-deposited film made of aluminum oxide is more preferably 7 nm or more and 15 nm or less.

[0176] The thickness of the vapor-deposited film made of silicon oxide is preferably 10 nm or more and 50 nm or less. A film thickness of 10 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 50 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 50 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the film thickness of the vapor-deposited film made of silicon oxide is more preferably 20 nm or more and 40 nm or less.

[0177] The inorganic compound layer can be formed, for example, by vacuum film formation. Vacuum film formation can use physical vapor deposition or chemical vapor deposition. Physical vapor deposition methods include, but are not limited to, vacuum deposition, sputtering, and ion plating. Chemical vapor deposition methods include, but are not limited to, thermal CVD (Chemical Vapor Deposition), plasma CVD, and photo CVD.

[0178] In the vacuum film formation, resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, induction heating vacuum evaporation, sputtering, reactive sputtering, dual magnetron sputtering, plasma enhanced chemical vapor deposition (PECVD), and the like are particularly preferably used. However, in terms of productivity, vacuum evaporation is currently the most superior. As a heating means for vacuum evaporation, it is preferable to use any of the electron beam heating method, resistance heating method, and induction heating method.

[0179] The coating layer can be formed, for example, by coating. In this case, a coating liquid containing a resin such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, or epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may also be added to the coating liquid.

[0180] The coating layer may be an organic-inorganic composite layer containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolyzate of a metal alkoxide, and a water-soluble polymer. This organic-inorganic composite layer may further contain at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolyzate of a silane coupling agent.

[0181] Examples of metal alkoxides and their hydrolysates contained in the organic-inorganic composite layer include compounds represented by the general formula M(OR), such as tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3]. n and hydrolysates thereof. One of these may be contained alone, or two or more may be contained in combination.

[0182] The total content of the metal alkoxide, its hydrolysate, or their reaction products in the coating liquid used to form the organic-inorganic composite layer may be, for example, 40% by mass or more, 50% by mass or more, or 65% by mass or more, from the viewpoint of oxygen barrier property. The total content of the metal alkoxide, its hydrolysate, or their reaction products in the coating liquid may be, for example, 70% by mass or less.

[0183] The water-soluble polymer contained in the organic-inorganic composite layer is not particularly limited, and examples thereof include polyvinyl alcohol-based polymers, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving the oxygen gas barrier property, the water-soluble polymer preferably contains a polyvinyl alcohol-based water-soluble polymer. The number-average molecular weight of the water-soluble polymer is, for example, 40,000 to 180,000.

[0184] The polyvinyl alcohol-based water-soluble polymer contained in the organic-inorganic composite layer can be obtained, for example, by saponifying (including partial saponification) polyvinyl acetate. This water-soluble polymer may have several tens of percent or only a few percent of acetate groups remaining.

[0185] The content of the water-soluble polymer in the coating liquid used to form the organic-inorganic composite layer may be, for example, 15% by mass or more, or 20% by mass or more, from the viewpoint of oxygen barrier properties, and may be, for example, 50% by mass or less, or 45% by mass or less, from the viewpoint of oxygen barrier properties.

[0186] Silane coupling agents used in the organic-inorganic composite layer include silane coupling agents having an organic functional group. Examples of such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. Silane coupling agents selected from these, their hydrolyzates, and their reaction products can be used alone or in combination of two or more.

[0187] It is preferable to use a silane coupling agent having an epoxy group as an organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The silane coupling agent having an epoxy group may have an organic functional group other than the epoxy group, such as a vinyl group, an amino group, a methacryl group, or a ureyl group. One of the silane coupling agents selected from these, their hydrolyzates, and their reaction products may be used alone or in combination of two or more.

[0188] A silane coupling agent having an organic functional group, its hydrolyzate, or a reaction product thereof can further improve the oxygen barrier property of the organic-inorganic composite layer and the adhesion to an adjacent layer through the interaction between the organic functional group and the hydroxyl group of the water-soluble polymer. In particular, when the silane coupling agent, its hydrolyzate, or a reaction product thereof has an epoxy group and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction between the epoxy group and the hydroxyl group of the PVA can further improve the oxygen barrier property and the adhesion to an adjacent layer.

[0189] The total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid used to form the organic-inorganic composite layer may be, for example, 1% by mass or more, or 2% by mass or more, from the viewpoint of oxygen barrier properties. Also, the total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid may be, for example, 15% by mass or less, or 12% by mass or less, from the viewpoint of oxygen barrier properties.

[0190] The gas barrier layer 5 is preferably subjected to the above-mentioned surface treatment, which can improve the adhesion between the gas barrier layer 5 and the adjacent layer. The gas barrier layer 5 may be made of a nanocomposite material.

[0191] The thickness of the coating layer is preferably 50 nm to 1000 nm, more preferably 100 nm to 500 nm. When the thickness of the gas barrier coating layer is 50 nm or more, more sufficient gas barrier properties tend to be obtained, and when it is 1000 nm or less, sufficient flexibility tends to be maintained.

[0192] <Anchor coat layer> The laminate 10E may further include an anchor coat layer (not shown) on the surface of the intermediate layer 8 on which the gas barrier layer 5 is formed. Alternatively, the laminate 10E may further include an anchor coat layer (not shown) on one of the main surfaces of the base layer 1 that faces the first adhesive layer 3A. The anchor coat layer can be formed using a known anchor coat agent. This can improve the adhesion of the inorganic compound layer made of metal oxide. Examples of anchor coat agents include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoints of heat resistance and interlayer adhesive strength, polyester-based polyurethane resins are preferred as the anchor coat agent.

[0193] 6 includes a printed layer 4 between the base material layer 1 and the first adhesive layer 3A, but the printed layer 4 may be included anywhere between the protective layer 6 and the sealant layer 2. Because the base material layer 1 and intermediate layer 8 included in the laminate 10E are transparent, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10E is observed from the protective layer 6 side, regardless of the position of the printed layer 4. According to one example, it is preferable that the printed layer 4 be included between the intermediate layer 8 and the protective layer 6, as this makes the pattern displayed by the printed layer 4 more clearly visible.

[0194] Also, in Figure 6, the laminate 10E includes a gas barrier layer 5 on the side of the intermediate layer 8 facing the sealant layer 2, but the laminate 10E may also include a gas barrier layer 5 on the side of the intermediate layer 8 facing the base layer 1.

[0195] The proportion of polyethylene in the laminate 10E is, for example, 90% by mass or more, which makes the laminate 10E a highly recyclable mono-material.

[0196] <5.4> Effects Like the laminate 10A1, the laminate 10E described above includes a polyethylene-containing layer having a crystallinity within the above range as the base layer 1. Therefore, like the laminate 10A1, the laminate 10E has excellent heat resistance.

[0197] The laminate 10E also includes a protective layer 6. As described above, the protective layer 6 reduces thermal damage to the surface of the laminate during heat sealing. Therefore, the laminate 10E can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for the laminate 10E, the temperature range for heat sealing performed for bag formation is expanded, further reducing the likelihood of a decrease in productivity.

[0198] Furthermore, the laminate 10E includes an intermediate layer 8 having a crystallinity within the above range. This intermediate layer 8 increases the strength, particularly the puncture strength, of the laminate 10E. Therefore, the laminate 10E has excellent strength, particularly the puncture strength.

[0199] Furthermore, in the laminate 10E, the base layer 1, the intermediate layer 8, and the sealant layer 2 all contain polyethylene, and therefore, this laminate has excellent recyclability.

[0200] Furthermore, laminates with a high proportion of polyethylene are weaker than other laminates, and therefore are frequently folded when used as packaging materials. Frequent folding increases the likelihood of pinholes occurring, but laminate 10E, which has excellent puncture resistance, is less likely to develop pinholes.

[0201] Furthermore, in the laminate 10E, since the base material layer 1 and the intermediate layer 8 are transparent, the pattern displayed by the printed layer 4 can be clearly seen when the printed layer 4 is observed from the protective layer 6 side, regardless of the position of the printed layer 4 between the base material layer 1 and the sealant layer 2. Furthermore, in a packaged article including the above-described laminate 10E, the contents have high visibility.

[0202] <6> Sixth embodiment <6.1> Laminate FIG. 7 is a cross-sectional view schematically showing a laminate according to a sixth embodiment of the present invention. 7 includes a protective layer 6, a base layer 1, a printed layer 4, a first adhesive layer 3A, an intermediate layer 8, a gas barrier layer 5, a second adhesive layer 3B, and a sealant layer 2, in this order. The laminate 10F is similar to the laminate 10E except that the crystallinity of the intermediate layer 8 is less than 35%. Of the layers included in the laminate 10F, the layers other than the intermediate layer 8, i.e., the protective layer 6, the base layer 1, the printed layer 4, the first adhesive layer 3A, the gas barrier layer 5, the second adhesive layer 3B, and the sealant layer 2, can be the same as those described in the fifth embodiment.

[0203] <6.2> Middle class The intermediate layer 8 contains polyethylene. As the polyethylene, for example, the polyethylenes described above for the base layer 1 can be used. The intermediate layer 8 is, for example, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very-low-density polyethylene (VLDPE).

[0204] The polyethylene contained in the intermediate layer 8 may be the same as or different from the polyethylene contained in the base layer 1. Furthermore, the intermediate layer 8 may further contain the additives described above.

[0205] The proportion of polyethylene in the mid layer 8 is preferably 50% by mass or more, and more preferably 80% by mass or more. According to one example, the mid layer 8 is made of polyethylene. According to another example, the mid layer 8 is made of polyethylene and an additive.

[0206] The crystallinity of the intermediate layer 8 is less than 35%. The crystallinity of the intermediate layer 8 is preferably 30% or less. The crystallinity of the intermediate layer 8 is preferably 15% or more.

[0207] An intermediate layer 8 having a crystallinity of less than 35% can increase the strength, particularly the drop strength, of the laminate 10F. An unstretched film is preferably used as such an intermediate layer 8. From the viewpoint of drop strength, it is preferable that the intermediate layer 8 is an unstretched film having a crystallinity of less than 35% and the base layer 1 is an oriented film having a crystallinity of 35% or more.

[0208] In this embodiment, an intermediate layer having a crystallinity of 35% or more may be used. When an intermediate layer having a crystallinity of 35% or more is used, the strength, particularly the puncture strength, of the laminate 10 can be improved. The intermediate layer having a crystallinity of 35% or more is preferably a stretched film.

[0209] The thickness of the intermediate layer 8 is preferably in the range of 10 μm to 200 μm, and more preferably in the range of 15 μm to 50 μm.

[0210] The intermediate layer 8 can be manufactured by known methods such as the above-mentioned casting method and inflation method, and it is also possible to use a multilayer polyethylene film as the base layer 1, in which polyethylenes of different densities are extruded by a co-extrusion method.

[0211] <Anchor coat layer> The laminate 10F may further include an anchor coat layer (not shown) on the surface of the intermediate layer 8 on which the gas barrier layer 5 is formed. Alternatively, the laminate 10F may further include an anchor coat layer (not shown) on the main surface of the base layer 1 that faces the first adhesive layer 3A. The anchor coat layer may be the same as that described in the fifth embodiment.

[0212] In FIG. 7, the laminate 10F includes a gas barrier layer 5 between the intermediate layer 8 and the second adhesive layer 3B, but the laminate 10F may also include a gas barrier layer 5 between the first adhesive layer 3A and the intermediate layer 8.

[0213] 7, the printed layer 4 is provided between the base material layer 1 and the first adhesive layer 3A, but it is preferable that the printed layer 4 be provided between the protective layer 6 and the first adhesive layer 3A. In this case, when the laminate 10F is observed from the protective layer 6 side, the pattern displayed by the printed layer 4 is easily seen clearly.

[0214] In addition, in the laminate 10F, the printed layer 4 and the gas barrier layer 5 may be omitted.

[0215] The proportion of polyethylene in the laminate 10F is, for example, 90% by mass or more, which makes the laminate 10F a highly recyclable mono-material.

[0216] <6.3> Effects In the above-described laminate 10F, the crystallinity of the base layer 1 is within the above range. Therefore, like the laminate 10A1, the laminate 10F has excellent heat resistance.

[0217] The laminate 10F also includes a protective layer 6. As described above, the protective layer 6 reduces thermal damage to the surface of the laminate during heat sealing. Therefore, the laminate 10F can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for the laminate 10F, the temperature range for heat sealing performed for bag formation is expanded, further reducing the likelihood of a decrease in productivity.

[0218] The laminate 10F also includes an intermediate layer 8 having a crystallinity within the above range. This intermediate layer 8 increases the strength of the laminate 10F, particularly its drop resistance. That is, when the laminate 10F is used in a package, the intermediate layer 8 located on the inner side of the base layer 1 is softer than the base layer 1. This structure is suitable for absorbing the impact that occurs when a packaged item using the laminate 10F as a packaging material is dropped. Therefore, a packaged item using the laminate 10F as a packaging material is less likely to be damaged (broken) by being dropped. Therefore, the laminate 10F has excellent strength, particularly its drop resistance.

[0219] Furthermore, the laminate 10F has excellent recyclability because the base layer 1, the intermediate layer 8, and the sealant layer 2 all contain polyethylene.

[0220] <7> Seventh embodiment <7.1> Laminate FIG. 8 is a cross-sectional view schematically showing a laminate according to a seventh embodiment of the present invention. The laminate 10G shown in FIG. 8 includes a protective layer 6, a base layer 1, a printed layer 4, a first adhesive layer 3A, an intermediate layer 8, an inorganic compound layer 5, a coating layer 7, a second adhesive layer 3B, and a sealant layer 2, in this order. The laminate 10G has a polyethylene content of 90% by mass or more. The laminate 10G is similar to the laminate 10E according to the fifth embodiment, in which the gas barrier layer 5 includes an inorganic compound layer and a coating layer. The protective layer 6, base layer 1, printed layer 4, first adhesive layer 3A, intermediate layer 8, inorganic compound layer 5, coating layer 7, second adhesive layer 3B, and sealant layer 2 described in the fifth embodiment can be used.

[0221] <7.2> Effects Like laminate 10A1, laminate 10G includes a polyethylene-containing layer having a crystallinity within the above range as base layer 1. Therefore, like laminate 10A1, laminate 10G has excellent heat resistance.

[0222] The laminate 10G also includes a protective layer 6. As described above, the protective layer 6 reduces thermal damage to the surface of the laminate during heat sealing. Therefore, the laminate 10G can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for the laminate 10G, the temperature range for heat sealing performed for bag formation is expanded, further reducing the likelihood of a decrease in productivity.

[0223] Furthermore, the laminate 10G includes an intermediate layer 8 having a crystallinity within the above range. This intermediate layer 8 increases the strength, particularly the puncture strength, of the laminate 10G. Therefore, the laminate 10G has excellent strength, particularly the puncture strength.

[0224] In the laminate 10G, the base layer 1, the intermediate layer 8, and the sealant layer 2 all contain polyethylene, with the proportion of polyethylene being 90% by mass or more. This laminate has excellent recyclability.

[0225] Furthermore, laminates with a high proportion of polyethylene are weaker than other laminates, and therefore are frequently bent when used as packaging materials. Frequent bending increases the likelihood of pinholes occurring, but Laminate 10G, which has excellent puncture resistance, is less likely to develop pinholes.

[0226] Furthermore, in the laminate 10G, since the base material layer 1 and the intermediate layer 8 are transparent, for example, no matter where the printed layer 4 is located between the base material layer 1 and the sealant layer 2, the pattern displayed by the printed layer 4 is clearly visible when the printed layer 4 is observed from the protective layer 6 side. Furthermore, in a packaged article including the above-described laminate 10G, the contents have high visibility.

[0227] <8> Eighth embodiment <8.1> Laminate FIG. 9 is a cross-sectional view schematically showing a laminate according to an eighth embodiment of the present invention. The laminate 10H shown in FIG. 9 includes a protective layer 6, a base material layer 1, a printed layer 4, a first adhesive layer 3A, an intermediate layer 8, an inorganic compound layer 5, a coating layer 7, a second adhesive layer 3B, and a sealant layer 2, in this order. The laminate 10H has a polyethylene content of 90% by mass or more. The laminate 10H is similar to the laminate 10F according to the sixth embodiment, in which the gas barrier layer 5 includes an inorganic compound layer and a coating layer. The protective layer 6, base material layer 1, printed layer 4, first adhesive layer 3A, intermediate layer 8, inorganic compound layer 5, coating layer 7, second adhesive layer 3B, and sealant layer 2 of the laminate 10H can be those described in the sixth embodiment.

[0228] <8.2> Effects In the laminate 10H, the crystallinity of the base layer 1 is within the above range. Therefore, the laminate 10H has excellent heat resistance, similar to the laminate 10A1.

[0229] The laminate 10H also includes a protective layer 6. As described above, the protective layer 6 reduces thermal damage to the surface of the laminate during heat sealing. Therefore, the laminate 10H can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for the laminate 10H, the temperature range for heat sealing performed for bag formation is expanded, further reducing the likelihood of a decrease in productivity.

[0230] The laminate 10H also includes an intermediate layer 8 having a crystallinity within the above range. This intermediate layer 8 increases the strength of the laminate 10H, particularly its drop resistance. That is, when the laminate 10H is used in a package, the intermediate layer 8 located on the inner side of the base layer 1 is softer than the base layer 1. This structure is suitable for absorbing the impact that occurs when a packaged item using the laminate 10H as a packaging material is dropped. Therefore, a packaged item using the laminate 10H as a packaging material is less likely to be damaged (broken) by being dropped. Therefore, the laminate 10H has excellent strength, particularly its drop resistance.

[0231] The laminate 10H has a polyethylene content of 90% by mass or more, which makes the laminate 10H highly recyclable.

[0232] The printing layer 4 may be provided on the surface of the base layer 1, on the surface of the intermediate layer 8, or on the back surface of the intermediate layer 8. In any case, the images such as patterns and characters displayed by the printing layer 4 can be seen with good visibility. The printing layer 4 may be omitted.

[0233] <9> Ninth embodiment FIG. 10 is a diagram schematically illustrating a packaged article according to a ninth embodiment of the present invention.

[0234] Packaged article 100A shown in FIG. 10 includes a package 110A and contents housed therein.

[0235] The package 110A is a flat pouch. The package 110A includes a pair of main body films. Each of the main body films is one of the laminates described in the first to eighth embodiments, or is cut out from such a laminate. The main body films are overlapped with their sealant layers facing each other, and the peripheral edges are heat-sealed to each other. The package 110A has a notch in the heat-sealed portion as an easy-open structure.

[0236] The contents may be any of liquids, solids, and mixtures thereof, such as food or medicine.

[0237] <10> Tenth embodiment FIG. 11 is a diagram schematically illustrating a packaged article according to a tenth embodiment of the present invention.

[0238] 11 includes a package 110B and contents housed therein. The contents may be the same as those described for the package 100A, for example.

[0239] The package 110B is a stand-up pouch. The package 110B includes a pair of main and bottom films. Each of these films is one of the laminates described in the first to eighth embodiments, or is cut out from the laminate.

[0240] The pair of main films are overlapped with their sealant layers facing each other, and their peripheral edges are heat-sealed to each other except for one end and the area nearby. The bottom film is folded in half to form a mountain fold when viewed from the sealant layer side, and is sandwiched between the pair of main films at the one end with the mountain fold facing the other end of the main film. The bottom film is heat-sealed to the pair of main films except for its center. The outer surfaces of the bottom films are bonded to each other at both sides of the bottom of the package 110B.

[0241] The package 110B has a notch as an easy-open structure at the portion where the main film is heat-sealed. The easy-open structure may be provided so that the upper corner of the packaged article 100B can be used as a mouth when the packaged article 100B is opened. Alternatively, the packaged article 100B may further include a mouth member and a lid body described in the eleventh embodiment.

[0242] <11> Eleventh embodiment FIG. 12 is a diagram schematically illustrating a packaged article according to an eleventh embodiment of the present invention.

[0243] 12 includes a package 110C and contents housed therein. The contents are, for example, the same as those described for the package 100A.

[0244] The package 110C is a gusset-type pouch and includes a container body 110C1, a mouth member 110C2, and a lid 110C3.

[0245] The container body 110C1 includes a pair of body films and a pair of side films.

[0246] The pair of main films are overlapped with their sealant layers facing each other and sandwiching a portion of the mouth member 110C2 at one end. The peripheral edges of the main films are heat-sealed to the mouth member 110C2 at the one end and are also heat-sealed to each other in the vicinity of the one end. The peripheral edges of the main films are also heat-sealed to each other at the opposite end, except for the side regions.

[0247] Each of the side films is folded in half to form a mountain fold when viewed from the sealant layer side. The side films are sandwiched between a pair of main films on both sides of the main films with the mountain folds facing each other. A portion of the periphery of each of the side films is heat-sealed to one of the main films, and the remaining portion of the periphery is heat-sealed to the other main film. The outer surfaces of the side films are bonded together at the top and bottom of the package 110C. The container body 110C1 may further include a bottom film.

[0248] As described above, the mouth member 110C2 is sandwiched between the main body films and includes a portion where they are heat-sealed. The mouth member 110C2 further includes a mouth portion that protrudes outward from the container body 110C1. The mouth portion has a substantially cylindrical shape and is provided with a male thread on the outer surface of the side wall. The lid body 110C3 has a cylindrical shape with a bottom. The lid body 110C3 has a female thread on the inner surface of the side wall that screws into the mouth portion of the mouth member 110C2. [Example]

[0249] The results of tests carried out in connection with the present invention are described below. (1) Test A (1.1) Manufacturing of Laminate (1.1.1) Example 1A The laminate 10A2 shown in FIG. 2 was produced by the following method. First, a polyethylene film having a thickness of 25 μm and a crystallinity of 58.5% was prepared as a substrate layer. The crystallinity shown in this example and the examples and comparative examples described below was measured by the above-mentioned measurement method.

[0250] Next, a silicon oxide (SiO ) layer was formed as an inorganic compound layer on one surface of the base material layer. x ) A vapor-deposited film was formed. Then, a printing layer was formed on the inorganic compound layer.

[0251] Next, a dry lamination adhesive (urethane adhesive) was applied to the printed surface of the base layer, and a linear low-density polyethylene (LLDPE) film (60 μm thick) was attached to the base layer via this adhesive layer. In this manner, a laminate was produced.

[0252] (1.1.2) Example 2A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that no inorganic compound layer was provided.

[0253] (1.1.3) Example 3A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyamine-based gas barrier adhesive was used as the adhesive instead of the dry laminating adhesive (urethane-based adhesive).

[0254] (1.1.4) Example 4A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 25 μm and a crystallinity of 71.8% was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a crystallinity of 58.5%.

[0255] (1.1.5) Example 5A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 25 μm and a crystallinity of 55.9% was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a crystallinity of 58.5%.

[0256] (1.1.6) Example 6A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 20 μm and a crystallinity of 54.1% was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a crystallinity of 58.5%.

[0257] (1.1.7) Example 7A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 30 μm and a crystallinity of 55.9% was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a crystallinity of 58.5%.

[0258] (1.1.8) Example 8A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a 40 μm thick linear low-density polyethylene resin (LLDPE) film was used as the sealant layer instead of a 60 μm thick linear low-density polyethylene resin (LLDPE) film.

[0259] (1.1.9) Example 9A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a linear low-density polyethylene resin (LLDPE) film having a thickness of 120 μm was used as the sealant layer instead of the linear low-density polyethylene resin (LLDPE) film having a thickness of 60 μm.

[0260] (1.1.10) Example 10A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that no inorganic compound layer was provided and a polyamine-based gas barrier adhesive was used as the adhesive instead of a dry lamination adhesive (urethane-based adhesive).

[0261] (1.1.11) Example 11A The laminate 10A2 shown in Figure 2 was produced in the same manner as in Example 1A, except that no inorganic compound layer was provided and a urethane-based gas barrier adhesive was used as the adhesive instead of a dry lamination adhesive (urethane-based adhesive).

[0262] (1.1.12) Comparative Example 1A A laminate was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 32 μm and a crystallinity of 14.8% was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a crystallinity of 58.5%.

[0263] (1.1.13) Comparative example 2A A laminate was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 25 μm and a crystallinity of 20.6% was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a crystallinity of 58.5%.

[0264] (1.2) Measurement and evaluation methods The substrate layer used in the production of the laminate was subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see if it had a sharp diffraction peak corresponding to the (110) plane.

[0265] Furthermore, the laminate was evaluated for sealing property, heat resistance, visibility, and gas barrier property. The evaluation methods for sealing property, heat resistance, visibility, and gas barrier property are described below.

[0266] (1.2.1) Sealing performance evaluation method A sample cut from the laminate into a 10 cm square was folded in half with the sealant layer facing inward and heat-sealed using a heat seal tester. Specifically, the bottom seal temperature was set to 100°C, the top seal temperature was set to 120°C, and a pressure of 0.1 MPa was applied for 1 second. The presence or absence of melting of the sealed surface was then confirmed, and the area of ​​the top surface of the folded sample where the heat seal bar was applied was observed. If the sealed surface and the top surface of the sample were not melted, the top seal temperature was increased by 10°C increments while the bottom seal temperature was fixed at 100°C, and the same pressure and observation were repeated until at least one of the sealed surface and the top surface of the sample was melted. The sealability was then evaluated according to the following criteria. A: There was no melting on the top surface of the sample, and there were no problems with the appearance. B: The upper surface of the sample was melted, and there was a problem with the appearance.

[0267] (1.2.2) Heat resistance evaluation method The laminate was cut into 10 cm square samples, which were then folded in half with the sealant layer facing inward. The bottom seal temperature of the heat seal tester was set to 30°C, and the top seal temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample for 1 second. The presence or absence of melting of the sealed surface was confirmed, and the area of ​​the top surface of the folded sample that had been touched by the heat seal bar was observed to see if it was adhering to the heat seal bar. Heat resistance was evaluated according to the following criteria. A: The top surface of the sample did not adhere to the heat seal bar. B: The top surface of the sample adhered to the heat seal bar.

[0268] (1.2.3) Visibility evaluation method The pattern displayed by the printing layer was visually observed from the substrate layer side, and the visibility was evaluated according to the following criteria. A: The pattern displayed by the printing layer was clearly visible. B: The pattern displayed by the printing layer was blurred and unclear.

[0269] (1.2.4) Gas barrier property evaluation method The laminate was subjected to a boiling treatment, and then the oxygen transmission rate (OTR) was measured at 30°C and a relative humidity of 70%. This measurement was carried out in accordance with JIS K-7126, Method B. The oxygen transmission rate was then evaluated with reference to the following criteria to evaluate the gas barrier properties. A: OTR is 10cc / m 2 ·day·atm was less than. B: OTR is 10cc / m 2 ·day·atm or more.

[0270] (1.3) Results The results of the above measurements and evaluations are summarized in Tables 1-1 and 1-2 below.

[0271] [Table 1-1]

[0272] [Table 1-2]

[0273] As shown in Tables 1-1 and 1-2, all of the laminates having a crystallinity of 35% or more in the base layer exhibited good sealing properties, heat resistance, and visibility. In contrast, all of the laminates having a crystallinity of less than 35% in the base layer exhibited insufficient sealing properties, heat resistance, and visibility.

[0274] (2) Test B (2.1) Manufacturing of Laminate (2.1.1) Example 1B The laminate 10B shown in Fig. 3 was produced by the following method. In this example, an anchor coat layer was further provided between the base layer 1 and the gas barrier layer 5, and an inorganic compound layer and a coating layer were provided as the gas barrier layer 5.

[0275] First, coating solutions for forming an anchor coating agent, a protective layer, and a covering layer were prepared by the following method: In this example, the protective layer and the covering layer were formed using the same coating solution.

[0276] (Preparation of anchor coating agent) Acrylic polyol and tolylene diisocyanate were mixed so that the number of OH groups in the acrylic polyol was equal to the number of NCO groups in the tolylene diisocyanate, and the mixture was diluted with ethyl acetate to a total solids content (total amount of acrylic polyol and tolylene diisocyanate) of 5% by mass. β-(3,4-epoxycyclohexyl)trimethoxysilane was added to the diluted mixture in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and the resulting mixture was mixed to prepare an anchor coating agent.

[0277] (Preparation of Coating Solution for Forming Protective Layer and Covering Layer) A coating liquid for forming a protective layer and a covering layer containing an organic-inorganic mixture (hereinafter simply referred to as the "coating liquid") was prepared by mixing the following liquids A, B, and C in a mass ratio of 70 / 20 / 10, respectively. Solution A: A hydrolysis solution with a solid content of 5% by mass (SiO2 equivalent) obtained by adding 72.1 g of 0.1N hydrochloric acid to 17.9 g of tetraethoxysilane (Si(OC2H5)4) and 10 g of methanol and stirring for 30 minutes. Solution B: 5% by mass of polyvinyl alcohol in water / methanol (water:methanol mass ratio 95:5). Liquid C: A hydrolysis solution prepared by diluting 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate with a water / isopropyl alcohol mixture (water:isopropyl alcohol mass ratio 1:1) to a solids content of 5 mass%.

[0278] The substrate layer has a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.94 g / cm 3 The crystallinity shown in this example and the examples and comparative examples described below was measured by the above-mentioned measuring method.

[0279] Next, one surface of the base layer was subjected to a corona treatment, and then the coating solution prepared above was applied to the corona-treated surface of the base layer by gravure coating and dried to form a protective layer made of an organic / inorganic mixture and having a thickness of 0.5 μm (in a dry state).

[0280] Next, the other surface of the base layer was subjected to a corona treatment, and then the above-mentioned anchor coating agent was applied to the corona-treated surface of the base layer by gravure coating to form an anchor coating layer with a thickness of 0.1 μm (in a dry state).

[0281] Next, an electron beam heating vacuum deposition apparatus was used to deposit silicon oxide (SiO x) A vapor-deposited film having a thickness of 40 nm was formed. Subsequently, the coating liquid prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture having a thickness of 0.3 μm (in a dry state).

[0282] Thereafter, a pattern was printed on the coating layer with water-based flexographic ink to form a print layer.

[0283] Next, a dry lamination adhesive (urethane adhesive) was applied to the printed surface of the base layer, and a linear low-density polyethylene (LLDPE) film (60 μm thick) was attached to the base layer via this adhesive layer. In this manner, a laminate was produced.

[0284] (2.1.2) Example 2B The laminate 10B shown in FIG. 3 was fabricated using a polyethylene film having a thickness of 25 μm, a crystallinity of 55.9%, a haze of 5.9%, and a density of 0.95 g / cm 3 instead of the polyethylene film having a crystallinity of 58.5%. 3 This polyethylene film was biaxially stretched and corona treated on one side.

[0285] (2.1.3) Example 3B The laminate 10B shown in FIG. 3 was produced in the same manner as in Example 2B, except that no protective layer was provided.

[0286] (2.1.4) Example 4B The laminate 10B shown in FIG. 3 was produced in the same manner as in Example 1B, except that instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin, a protective layer having a thickness of 0.5 μm made of a urethane resin was formed.

[0287] (2.1.5) Example 5B The laminate 10B shown in FIG. 3 was produced in the same manner as in Example 1B, except that instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin, a protective layer having a thickness of 1 μm made of a urethane resin was formed.

[0288] (2.1.6) Example 6B The laminate 10B shown in FIG. 3 was produced in the same manner as in Example 1B, except that instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin, a protective layer having a thickness of 1 μm made of ethylene-vinyl alcohol copolymer (EVOH) was formed.

[0289] (2.1.7) Example 7B The laminate 10B shown in FIG. 3 was produced in the same manner as in Example 1B, except that instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin, a protective layer having a thickness of 1 μm made of an acrylic resin was formed.

[0290] (2.1.8) Comparative example 1B The laminate 10B shown in FIG. 3 was produced in the same manner as in Example 1B, except for the following: no protective layer was provided. Furthermore, instead of using the above-mentioned polyethylene film with a crystallinity of 58.5%, a laminate with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm was used as the substrate layer. 3 The polyethylene film was corona treated on one side.

[0291] (2.2) Measurement and evaluation methods The substrate layer used in the production of the laminate was subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see if it had a sharp diffraction peak corresponding to the (110) plane.

[0292] The laminate was also evaluated for sealing property, heat resistance, visibility, and recyclability. The evaluation methods for sealing property, heat resistance, visibility, and recyclability are described below.

[0293] (2.2.1) Sealing performance evaluation method A sample of the laminate cut into a 10 cm square was folded in half with the sealant layer facing inward and heat-sealed using a heat seal tester. Specifically, a temperature of 140°C and a pressure of 0.1 MPa were applied to the folded sample for 1 second. The area of ​​the sample surface where the heat seal bar was applied was then observed, and the sealability was evaluated according to the following criteria. A: There was no melting on the surface of the sample, and there were no problems with the appearance. B: The surface of the sample was melted, and there was a problem with the appearance.

[0294] (2.2.2) Heat resistance evaluation method The laminate was cut into 10 cm square samples, which were then folded in half with the sealant layer facing inward. The bottom seal temperature of the heat seal tester was set to 30°C, and the top seal temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample for 1 second. The presence or absence of melting of the sealed surface was confirmed, and the area of ​​the top surface of the folded sample that had been touched by the heat seal bar was observed to see if it was adhering to the heat seal bar. Heat resistance was evaluated according to the following criteria. A: The top surface of the sample did not adhere to the heat seal bar. B: The top surface of the sample adhered to the heat seal bar. Furthermore, for the laminates having a protective layer, the heat resistance was further evaluated in the same manner as above, except that the top seal temperature was set to 190°C.

[0295] (2.2.3) Visibility evaluation method Visibility was evaluated using the method described in (1.2.3).

[0296] (2.2.4) Recyclability evaluation method The proportion of polyethylene in the total mass of the laminate was calculated. This proportion was used to evaluate recyclability with reference to the following criteria. Here, evaluation A means that the monomaterial has excellent recyclability. A: The proportion of polyethylene was 90% by mass or more. B: The proportion of polyethylene was less than 90% by mass.

[0297] (2.3) Results The results of the above measurements and evaluations are summarized in Table 2 below.

[0298] [Table 2]

[0299] As shown in Table 2, all laminates in which the crystallinity of the base layer was 35% or more had good heat resistance and visibility while being suitable for recycling. Furthermore, laminates in which the crystallinity of the base layer was 35% or more and which had a protective layer also had excellent sealing properties. In contrast, laminates in which the crystallinity of the base layer was less than 35% and which did not have a protective layer had insufficient sealing properties, heat resistance, and visibility.

[0300] (3) Test C (3.1) Manufacturing of laminate (3.1.1) Example 1C 4 was produced by the following method. In this example, an anchor coat layer was further provided between the base material layer 1 and the inorganic compound layer 5.

[0301] First, an anchor coating agent and a coating liquid for forming a covering layer were prepared in the same manner as in Example 1 B. Also, an organic solvent solution of a polyamideimide resin (non-volatile component concentration 5% by mass) was prepared as a coating liquid for forming a protective layer.

[0302] The substrate layer has a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.950 g / cm 3 A polyethylene film having the following formula was prepared. This polyethylene film was subjected to corona treatment on both sides. The crystallinity shown in this example and the examples and comparative examples described below was measured by the above-mentioned measuring method.

[0303] Next, the coating solution containing the polyamideimide prepared above was applied by gravure coating to one of the corona-treated surfaces of the substrate layer and dried to form a protective layer having a thickness of 0.5 μm.

[0304] Next, the anchor coating agent described above was applied to the other corona-treated surface of the base layer by gravure coating to form an anchor coating layer with a thickness of 0.1 μm (in a dry state).

[0305] Next, an electron beam heating vacuum deposition apparatus was used to deposit silicon oxide (SiO x ) A vapor-deposited film having a thickness of 40 nm was formed. Subsequently, the coating solution for forming a coating layer prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture having a thickness of 0.3 μm (in a dry state).

[0306] Thereafter, an image was formed on the coating layer by flexographic printing using a water-based flexographic ink, thereby forming a print layer.

[0307] Next, a dry lamination adhesive (urethane adhesive) was applied to the printed surface of the base layer, and a linear low-density polyethylene (LLDPE) film (60 μm thick) was attached to the base layer via this adhesive layer. In this manner, a laminate was produced.

[0308] (3.1.2) Example 2C Laminate 10C shown in FIG. 4 was produced in the same manner as in Example 1C, except that the thickness of the protective layer was changed from 0.5 μm to 1 μm, and further, no covering layer was provided.

[0309] (3.1.3) Example 3C A laminate 10C shown in FIG. 4 was produced in the same manner as in Example 1C, except that the thickness of the protective layer was changed from 0.5 μm to 3 μm.

[0310] (3.1.4) Example 4C A laminate 10C shown in FIG. 4 was produced in the same manner as in Example 1C, except that no protective layer was provided.

[0311] (3.1.5) Comparative example 1C Laminate 10C shown in Figure 4 was produced in the same manner as in Example 1C, except for the following: no protective layer was provided. Furthermore, instead of using the above-mentioned polyethylene film with a crystallinity of 58.5%, a polyethylene film with a thickness of 25 µm, a crystallinity of 27.6%, and a haze of 21.5% was used as the substrate layer.

[0312] (3.2) Measurement and evaluation methods The substrate layer used in the production of the laminate was subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see if it had a sharp diffraction peak corresponding to the (110) plane.

[0313] The laminate was also evaluated for sealing property, heat resistance, visibility, and recyclability. The evaluation methods for sealing property, heat resistance, visibility, and recyclability are described below.

[0314] (3.2.1) Sealing performance evaluation method The sealing property was evaluated by the method explained in (1.2.1).

[0315] (3.2.2) Heat resistance evaluation method Heat resistance was evaluated by the method explained in (2.2.2).

[0316] (3.2.3) Visibility evaluation method Visibility was evaluated using the method described in (1.2.3).

[0317] (3.2.3) Recyclability evaluation method Recyclability was evaluated using the method described in (2.2.4).

[0318] (3.3) Results The results of the above measurements and evaluations are summarized in Table 3 below.

[0319] [Table 3]

[0320] As shown in Table 3, all laminates in which the crystallinity of the base layer was 35% or more had good heat resistance and visibility while being suitable for recycling. Furthermore, laminates in which the crystallinity of the base layer was 35% or more and which had a protective layer also had excellent sealing properties. In contrast, laminates in which the crystallinity of the base layer was less than 35% and which did not have a protective layer had insufficient sealing properties, heat resistance, and visibility.

[0321] (4) Test D (4.1) Manufacturing of Laminate (4.1.1) Example 1D The laminate 10D shown in FIG. 5 was produced by the following method. First, the substrate layer and the intermediate layer had a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.94 g / cm 3 The crystallinity shown in this example and the examples and comparative examples described below was measured by the above-mentioned measuring method.

[0322] Next, on the intermediate layer, silicon oxide (SiO x ) A vapor-deposited film was formed to a thickness of 50 nm.

[0323] A dry laminating adhesive (urethane adhesive) was applied to the substrate layer to form a first adhesive layer. The substrate layer and the intermediate layer were bonded together with the first adhesive layer sandwiched between them so that the substrate layer and the inorganic compound layer faced each other. Next, a printing layer was formed on the back side of the intermediate layer opposite the surface on which the inorganic compound layer was formed.

[0324] Next, a linear low-density polyethylene (LLDPE) film (60 μm thick) was prepared as a sealant layer, and a dry lamination adhesive (urethane adhesive) was applied to the sealant layer to form a second adhesive layer. The base layer and sealant layer were then bonded together with the second adhesive layer sandwiched between them, so that the sealant layer and the printed layer faced each other. In this manner, a laminate was produced. (4.1.2) Example 2D The laminate 10D shown in FIG. 5 was produced in the same manner as in Example 1D, except that a gas-barrier polyamine-based adhesive was used instead of a urethane-based adhesive as the adhesive used in the first adhesive layer and the second adhesive layer.

[0325] (4.1.3) Example 3D The laminate 10D shown in FIG. 5 was fabricated using a polyethylene film having a thickness of 25 μm, a crystallinity of 71.8%, a haze of 4.1%, and a density of 0.95 g / cm 3 as the base layer, instead of using the polyethylene film having a crystallinity of 58.5% as the base layer. 3 This polyethylene film was a longitudinally uniaxially stretched film that had been subjected to a corona treatment on one side.

[0326] (4.1.4) Example 4D Laminate 10D shown in Fig. 5 was produced in the same manner as in Example 1D, except for the following: instead of using the polyethylene film with a crystallinity of 58.5% as the substrate layer, a polyethylene film with a thickness of 25 µm, a crystallinity of 55.9%, a haze of 5.9, and a density of 0.95 g / cm was used. 3 This polyethylene film was a biaxially stretched film, and one side of the film was subjected to corona treatment. Furthermore, instead of using the above-mentioned polyethylene film with a crystallinity of 58.5%, a polyethylene film with a thickness of 25 μm, a crystallinity of 71.8%, a haze of 4.1, and a density of 0.95 g / cm was used as the intermediate layer. 3The polyethylene film was a longitudinally uniaxially stretched film, and one side of the film was subjected to a corona treatment.

[0327] (4.1.5) Example 5D The laminate 10D shown in FIG. 5 was fabricated by using a polyethylene film having a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm 3 as the intermediate layer, instead of the polyethylene film having a crystallinity of 58.5%. 3 This was produced in the same manner as in Example 1D, except that a polyethylene film having a formula of 1.0 or less was used. This polyethylene film had been corona-treated on one side.

[0328] (4.1.6) Example 6D A laminate 10D shown in FIG. 5 was produced in the same manner as in Example 1D, except that no gas barrier layer was provided.

[0329] (4.1.7) Comparative Example 1D The laminate 10D shown in FIG. 5 was fabricated using a polyethylene film having a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm 3 as the base layer, instead of using the polyethylene film having a crystallinity of 58.5% as the base layer. 3 This was produced in the same manner as in Example 1D, except that a polyethylene film having a formula of 1.0 or less was used. This polyethylene film had been corona-treated on one side.

[0330] (4.1.8) Comparative example 2D The laminate 10D shown in FIG. 5 was fabricated by using a polyethylene film having a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm 3 as the base layer and intermediate layer, instead of using the polyethylene film having a crystallinity of 58.5% as the base layer and intermediate layer. 3 This was produced in the same manner as in Example 1D, except that a polyethylene film having a formula of 1.0 or less was used. This polyethylene film had been corona-treated on one side.

[0331] (4.1.9) Comparative example 3D Laminate 10D shown in Fig. 5 was produced in the same manner as in Example 1D, except for the following: instead of using the polyethylene film with a crystallinity of 58.5% as the substrate layer, a polyethylene film with a thickness of 25 µm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm was used. 3 The polyethylene film used was a polyethylene film having a thickness of 100 μm, which had been subjected to a corona treatment on one side, and no gas barrier layer was provided.

[0332] (4.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see whether it had a sharp diffraction peak corresponding to the (110) plane.

[0333] The laminate was also evaluated for sealing property, heat resistance, visibility, puncture strength, and gas barrier property. The evaluation methods for sealing property, heat resistance, visibility, puncture strength, and gas barrier property are described below.

[0334] (4.2.1) Sealing performance evaluation method The sealing property was evaluated by the method explained in (2.2.1).

[0335] (4.2.2) Heat resistance evaluation method Heat resistance was evaluated by the method explained in (1.2.2).

[0336] (4.2.3) Visibility evaluation method Visibility was evaluated using the method described in (1.2.3).

[0337] (4.2.4) Evaluation method for puncture strength A needle with a radius of 0.5 mm and a hemispherical tip was pressed against the laminate from the base layer side at a speed of 50 mm / min, and the maximum force required for the needle to penetrate was measured. This measurement was performed multiple times, and the arithmetic average of the maximum forces was obtained as the penetration strength.

[0338] (4.2.5) Gas barrier property evaluation method The gas barrier properties were evaluated by the method explained in (1.2.4).

[0339] (4.3) Results The results of the above measurements and evaluations are summarized in Tables 4-1 and 4-2 below.

[0340] [Table 4-1]

[0341] [Table 4-2]

[0342] As shown in Tables 4-1 and 4-2, all laminates in which the crystallinity of the base layer was 35% or higher had good sealing properties and heat resistance. Furthermore, laminates in which the crystallinity of the base layer and intermediate layer was 35% or higher also had excellent visibility and puncture strength. In contrast, laminates in which the crystallinity of the base layer was less than 35% had insufficient sealing properties, heat resistance, and visibility.

[0343] (5) Test E (5.1) Manufacturing of Laminate (5.1.1) Example 1E 6 was produced by the following method. In this example, an anchor coat layer was further provided between the intermediate layer 8 and the gas barrier layer 5, and an inorganic compound layer and a coating layer were provided as the gas barrier layer 5.

[0344] First, an anchor coating agent, a coating liquid for forming a covering layer, and a coating liquid for forming a protective layer were prepared in the same manner as in Example 1B. In this example, the protective layer and the covering layer were formed using the same coating liquid, as in Example 1B.

[0345] The substrate layer and the intermediate layer have a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.94 g / cm3 The crystallinity shown in this example and the examples and comparative examples described below was measured by the above-mentioned measuring method.

[0346] Next, one surface of the base layer was subjected to a corona treatment, and then the protective layer forming coating solution prepared above was applied to the corona-treated surface of the base layer by gravure coating and dried to form a protective layer made of an organic / inorganic mixture and having a thickness of 0.5 μm.

[0347] Next, the other surface of the base layer was subjected to a corona treatment, and then a pattern was printed with a water-based flexographic ink on the corona-treated surface of the base layer to form a print layer.

[0348] One surface of the intermediate layer was subjected to a corona treatment, and then the above-described anchor coating agent was applied to the corona-treated surface of the intermediate layer by gravure coating to form an anchor coating layer with a thickness of 0.1 μm (in a dry state).

[0349] Next, an electron beam heating vacuum deposition apparatus was used to deposit silicon oxide (SiO x A vapor-deposited film having a thickness of 40 nm was formed on the anchor coat layer. Subsequently, the coating solution for forming a coating layer prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture having a thickness of 0.3 μm (in a dry state).

[0350] Next, a dry laminating adhesive (urethane adhesive) was applied to the surface of the intermediate layer opposite to the surface on which the inorganic compound layer was formed to form a first adhesive layer. The base layer and the intermediate layer were bonded together with the first adhesive layer sandwiched between them so that the printed layer and the intermediate layer faced each other.

[0351] Next, a linear low-density polyethylene (LLDPE) film (60 μm thick) was prepared as a sealant layer. A dry lamination adhesive (urethane adhesive) was applied to the sealant layer to form a second adhesive layer. The base layer and sealant layer were then bonded together with the second adhesive layer sandwiched between them, so that the sealant layer and coating layer faced each other. In this manner, a laminate was produced.

[0352] (5.1.2) Example 2E Laminate 10E shown in Fig. 6 was produced in the same manner as in Example 1E, except for the following: Instead of using the above-mentioned polyethylene film with a crystallinity of 58.5% as the substrate layer and intermediate layer, a laminate with a thickness of 25 µm, a crystallinity of 55.9%, a haze of 5.9%, and a density of 0.95 g / cm3 was used. 3 The polyethylene film used was one side of which was corona treated.

[0353] (5.1.3) Example 3E Laminate 10E shown in FIG. 6 was produced in the same manner as in Example 2E, except for the following: no protective layer was provided. Furthermore, instead of using the above-mentioned polyethylene film with a crystallinity of 55.9%, a laminate with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm was used as the intermediate layer. 3 The polyethylene film used was one side of which was corona treated.

[0354] (5.1.4) Comparative Example 1E Laminate 10E shown in Fig. 6 was produced in the same manner as in Example 1E, except for the following: no protective layer was provided. Furthermore, instead of using the above-mentioned polyethylene film with a crystallinity of 58.5% as the substrate layer and intermediate layer, a polyethylene film with a thickness of 25 µm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm was used. 3 The polyethylene film used was one side of which was corona treated.

[0355] (5.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see whether it had a sharp diffraction peak corresponding to the (110) plane.

[0356] The laminate was also evaluated for sealing property, heat resistance, visibility, puncture strength, and recyclability. The evaluation methods for sealing property, heat resistance, visibility, puncture strength, and recyclability are described below.

[0357] (5.2.1) Sealing performance evaluation method The sealing property (heat resistance) was evaluated by the method explained in (2.2.1).

[0358] (5.2.2) Heat resistance evaluation method Heat resistance was evaluated by the method explained in (2.2.2).

[0359] (5.2.3) Visibility evaluation method Visibility was evaluated using the method described in (1.2.3).

[0360] (5.2.4) Evaluation method for puncture strength The puncture strength was evaluated by the method described in (4.2.4).

[0361] (5.2.5) Recyclability evaluation method Recyclability was evaluated using the method described in (2.2.4).

[0362] (5.3) Results The results of the above measurements and evaluations are summarized in Table 5 below.

[0363] [Table 5]

[0364] As shown in Table 5, all laminates in which the crystallinity of the base layer was 35% or higher had good heat resistance, visibility, and puncture strength. Furthermore, laminates in which the crystallinity of the base layer and intermediate layer was 35% or higher and which also had a protective layer also had excellent sealing properties and further improved puncture strength. In contrast, laminates in which the crystallinity of the base layer was less than 35% and which did not have a protective layer had insufficient sealing properties, heat resistance, visibility, and puncture strength.

[0365] (6) Test F (6.1) Manufacturing of Laminate (6.1.1) Example 1F 7 was produced by the following method. In this example, an anchor coat layer was further provided between the intermediate layer 8 and the gas barrier layer 5, and an inorganic compound layer and a coating layer were provided as the gas barrier layer 5.

[0366] First, an anchor coating agent, a coating liquid for forming a covering layer, and a coating liquid for forming a protective layer were prepared in the same manner as in Example 1B. In this example, the protective layer and the covering layer were formed using the same coating liquid, as in Example 1B.

[0367] The substrate layer has a thickness of 25 μm, a crystallinity of 58.5%, and a density of 0.950 g / cm 3 A polyethylene film having the following formula was prepared. This polyethylene film was subjected to a corona treatment on one side. The crystallinity shown in this example and the examples and comparative examples described below was measured by the above-mentioned measuring method.

[0368] Next, one surface of the base layer was subjected to a corona treatment, and then the protective layer forming coating solution prepared above was applied to the corona-treated surface of the base layer by gravure coating and dried to form a protective layer made of an organic / inorganic mixture and having a thickness of 0.5 μm.

[0369] Next, the other surface of the base layer was subjected to a corona treatment, and then a pattern was printed with a water-based flexographic ink on the corona-treated surface of the base layer to form a print layer.

[0370] Next, as the intermediate layer, a thickness of 25 μm, a crystallinity of 27.5%, and a density of 0.950 g / cm 3 A polyethylene film having the following characteristics was prepared. One side of this polyethylene film was subjected to a corona treatment.

[0371] The above-mentioned anchor coating agent was applied by gravure coating to form an anchor coating layer with a thickness of 0.1 μm (in a dry state).

[0372] Next, as an inorganic compound layer, silicon oxide (SiO x A vapor-deposited film having a thickness of 40 nm was formed on the anchor coat layer. Subsequently, the coating solution for forming a coating layer prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture having a thickness of 0.3 μm (in a dry state).

[0373] Next, a dry laminating adhesive (urethane adhesive) was applied to the surface of the intermediate layer opposite to the surface on which the inorganic compound layer was formed to form a first adhesive layer. The base layer and the intermediate layer were bonded together with the first adhesive layer sandwiched between them so that the printed layer and the intermediate layer faced each other.

[0374] Next, a linear low-density polyethylene (LLDPE) film (60 μm thick) was prepared as a sealant layer. A dry lamination adhesive (urethane adhesive) was applied to the sealant layer to form a second adhesive layer. The base layer and sealant layer were then bonded together with the second adhesive layer sandwiched between them, so that the sealant layer and coating layer faced each other. In this manner, a laminate was produced.

[0375] (6.1.2) Example 2F Laminate 10F shown in Fig. 7 was produced in the same manner as in Example 1F, except for the following: instead of using the polyethylene film with a crystallinity of 58.5% as the substrate layer, a polyethylene film with a thickness of 25 µm, a crystallinity of 55.9%, a haze of 21.5%, and a density of 0.95 g / cm 3The polyethylene film used was one side of which was corona treated.

[0376] (6.1.3) Example 3F Laminate 10F shown in Fig. 7 was produced in the same manner as in Example 1F, except for the following: no protective layer was provided. Furthermore, instead of using the above-mentioned polyethylene film having a crystallinity of 58.5% as the base layer and the above-mentioned polyethylene film having a crystallinity of 27.5% as the intermediate layer, a laminate having a thickness of 25 µm, a crystallinity of 55.9%, and a density of 0.95 g / cm was used. 3 The polyethylene film used was one side of which was corona treated.

[0377] (6.1.4) Comparative Example 1F Laminate 10F shown in FIG. 7 was produced in the same manner as in Example 1F, except for the following: no protective layer was provided. Furthermore, instead of using the above-mentioned polyethylene film with a crystallinity of 58.5%, a laminate with a thickness of 25 μm, a crystallinity of 27.5%, and a density of 0.950 g / cm was used as the base layer. 3 A polyethylene film having a thickness of 25 μm, a crystallinity of 55.9%, and a density of 0.95 g / cm was used as the intermediate layer. This polyethylene film was subjected to corona treatment on one side. Furthermore, instead of using the above-mentioned polyethylene film having a crystallinity of 27.5%, a polyethylene film having a thickness of 25 μm, a crystallinity of 55.9%, and a density of 0.95 g / cm was used as the intermediate layer. 3 The polyethylene film used was one side of which was corona treated.

[0378] (6.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see whether it had a sharp diffraction peak corresponding to the (110) plane.

[0379] The laminate was also evaluated for sealing property, heat resistance, drop strength, and recyclability. The evaluation methods for sealing property, heat resistance, drop strength, and recyclability are described below.

[0380] (6.2.1) Sealing performance evaluation method The sealing property was evaluated by the method explained in (2.2.1).

[0381] (6.2.2) Heat resistance evaluation method Heat resistance was evaluated by the method explained in (2.2.2).

[0382] (6.2.3) Drop Strength Evaluation Method The laminate was cut to a predetermined size and the edges were heat-sealed to create 10 bags. Each bag had an opening for inserting the contents. The bag dimensions were 100 mm x 150 mm. Next, 200 mL of tap water was filled into each bag, and the opening was heat-sealed to obtain a packaged product. Next, each packaged product was stored at 5°C for one day, and then dropped 50 times from a height of 1.5 m. The ratio of the number of packaged products whose bags broke within 50 tries to the total number of packaged products (10) was calculated as the drop strength.

[0383] (6.2.4) Recyclability evaluation method Recyclability was evaluated using the method described in (2.2.4).

[0384] (6.3) Results The results of the above measurements and evaluations are summarized in Table 6 below.

[0385] [Table 6]

[0386] As shown in Table 6, all laminates in which the crystallinity of the base layer was 35% or higher had good heat resistance while being suitable for recycling. Furthermore, laminates in which the crystallinity of the base layer was 35% or higher, the crystallinity of the intermediate layer was less than 35%, and a protective layer were provided also had excellent sealing properties and drop strength. In contrast, laminates in which the crystallinity of the base layer was less than 35% and no protective layer was provided had insufficient sealing properties, heat resistance, and drop strength.

[0387] (7) Test G (7.1) Manufacturing of laminates (7.1.1) Example 1G 8 was produced by the following method. In this example, an anchor coat layer was further provided between the intermediate layer 8 and the inorganic compound layer 5.

[0388] First, a coating liquid for forming an anchor coat layer and a coating liquid for forming a cover layer were prepared in the same manner as in Example 1B. Furthermore, a solution of polyamideimide resin in an organic solvent (non-volatile component concentration: 5% by mass) was prepared as a coating liquid for forming a protective layer.

[0389] The substrate layer and the intermediate layer have a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.950 g / cm 3 A polyethylene film having the following composition was prepared. This polyethylene film had a three-layer structure (HDPE / MDPE / HDPE) and was subjected to corona treatment on both sides. The crystallinity shown in this example and the examples and comparative examples described below was measured by the above-mentioned measurement method.

[0390] Next, the protective layer-forming coating solution prepared above was applied by gravure coating to one of the corona-treated surfaces of the base layer and dried to form a protective layer with a thickness of 0.5 μm. Subsequently, a pattern was printed with aqueous flexographic ink on the other corona-treated surface of the base layer to form a printed layer.

[0391] Next, the above-mentioned anchor coating agent was applied by gravure coating to one of the corona-treated surfaces of the intermediate layer to form an anchor coating layer with a thickness of 0.1 μm (in a dry state).

[0392] Next, as an inorganic compound layer, a transparent silicon oxide (SiO x A 40 nm thick vapor-deposited film was formed on the anchor coat layer. The O / Si ratio of the vapor-deposited film was set to 1.8 by adjusting the type of material used for vapor deposition.

[0393] Subsequently, the coating liquid for forming a coating layer prepared above was applied to the inorganic compound layer to form a coating layer made of an organic-inorganic mixture and having a thickness of 0.3 μm (in a dry state).

[0394] Next, a dry laminating adhesive (urethane adhesive) was applied to the surface of the intermediate layer opposite to the surface on which the inorganic compound layer was formed to form a first adhesive layer. The base layer and the intermediate layer were bonded together with the first adhesive layer sandwiched between them so that the printed layer and the intermediate layer faced each other.

[0395] Next, a linear low-density polyethylene (LLDPE) film (60 μm thick) was prepared as a sealant layer. A dry lamination adhesive (urethane adhesive) was applied to the sealant layer to form a second adhesive layer. The base layer and sealant layer were then bonded together with the second adhesive layer sandwiched between them, so that the sealant layer and coating layer faced each other. In this manner, a laminate was produced.

[0396] (7.1.2) Example 2G A laminate 10G shown in FIG. 8 was produced in the same manner as in Example 1G, except that the thickness of the protective layer was changed from 0.5 μm to 1 μm. (7.1.3) Example 3G A laminate 10G shown in FIG. 8 was produced in the same manner as in Example 1G, except that the thickness of the protective layer was changed from 0.5 μm to 3 μm. (7.1.4) Example 4G Laminate 10G shown in Figure 8 was produced in the same manner as in Example 1G, with the following exceptions: no protective layer was provided; and instead of using the polyethylene film with a crystallinity of 58.5% described above as the intermediate layer, a polyethylene film with a thickness of 25 µm, a crystallinity of 27.6%, and a haze of 21.5% was used. (7.1.5) Comparative Example 1G Laminate 10G shown in Figure 8 was produced in the same manner as in Example 1G, with the following exceptions: no protective layer was provided; and instead of using the polyethylene film with a crystallinity of 58.5% described above, a polyethylene film with a thickness of 25 µm and a crystallinity of 27.6% was used as the base layer and intermediate layer.

[0397] (7.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see whether it had a sharp diffraction peak corresponding to the (110) plane.

[0398] The laminate was also evaluated for sealing property, heat resistance, visibility, puncture strength, and recyclability. The evaluation methods for sealing property, heat resistance, visibility, puncture strength, and recyclability are described below.

[0399] (7.2.1) Sealing performance evaluation method The sealing property was evaluated by the method explained in (1.2.1).

[0400] (7.2.2) Heat resistance evaluation method Heat resistance was evaluated by the method explained in (2.2.2).

[0401] (7.2.3) Visibility evaluation method Visibility was evaluated using the method described in (1.2.3).

[0402] (7.2.4) Evaluation method for puncture strength The puncture strength was evaluated by the method described in (4.2.4).

[0403] (7.2.5) Recyclability evaluation method Recyclability was evaluated using the method described in (2.2.4). (7.3) Results The results of the above measurements and evaluations are summarized in Table 7 below.

[0404] [Table 7]

[0405] As shown in Table 7, all laminates in which the crystallinity of the base layer was 35% or higher had good heat resistance and visibility while being suitable for recycling. Furthermore, laminates in which the crystallinity of the base layer and intermediate layer was 35% or higher and which were provided with a protective layer also had excellent sealing properties and puncture strength. In contrast, laminates in which the crystallinity of the base layer was less than 35% and which were not provided with a protective layer had insufficient sealing properties, heat resistance, visibility, and puncture strength.

[0406] (8) Test G (8.1) Manufacturing of Laminates (8.1.1) Example 1H 9 was produced by the following method: In this example, an anchor coat layer was further provided between the intermediate layer 8 and the inorganic compound layer 5.

[0407] First, a coating liquid for forming an anchor coat layer and a coating liquid for forming a cover layer were prepared in the same manner as in Example 1B. Furthermore, a solution of polyamideimide resin in an organic solvent (non-volatile component concentration: 5% by mass) was prepared as a coating liquid for forming a protective layer.

[0408] A polyethylene film having a thickness of 25 μm, a crystallinity of 58.5%, and a haze of 1.6% was prepared as the substrate layer. This polyethylene film was subjected to corona treatment on both sides. The crystallinity shown in this example and the examples and comparative examples described below was measured using the above-mentioned measurement method.

[0409] Next, the protective layer-forming coating solution prepared above was applied by gravure coating to one of the corona-treated surfaces of the base layer and dried to form a protective layer with a thickness of 0.5 μm. Subsequently, a pattern was printed with aqueous flexographic ink on the other corona-treated surface of the base layer to form a printed layer.

[0410] A polyethylene film with a thickness of 25 μm, a crystallinity of 27.6%, and a haze of 21.5% was prepared as the intermediate layer. This polyethylene film was corona-treated on both sides. Next, the anchor coating agent described above was applied by gravure coating to one of the corona-treated surfaces of the intermediate layer to form an anchor coating layer with a thickness of 0.1 μm (in a dry state).

[0411] Next, as an inorganic compound layer, a transparent silicon oxide (SiO x A 40 nm thick vapor-deposited film was formed on the anchor coat layer. The O / Si ratio of the vapor-deposited film was set to 1.8 by adjusting the type of material used for vapor deposition.

[0412] Subsequently, the coating liquid for forming a coating layer prepared above was applied to the inorganic compound layer to form a coating layer made of an organic-inorganic mixture and having a thickness of 0.3 μm (in a dry state).

[0413] Next, a dry laminating adhesive (urethane adhesive) was applied to the surface of the intermediate layer opposite to the surface on which the inorganic compound layer was formed to form a first adhesive layer. The base layer and the intermediate layer were bonded together with the first adhesive layer sandwiched between them so that the printed layer and the intermediate layer faced each other.

[0414] Next, a linear low-density polyethylene (LLDPE) film (60 μm thick) was prepared as a sealant layer. A dry lamination adhesive (urethane adhesive) was applied to the sealant layer to form a second adhesive layer. The base layer and sealant layer were then bonded together with the second adhesive layer sandwiched between them, so that the sealant layer and coating layer faced each other. In this manner, a laminate was produced.

[0415] (8.1.2) Example 2H Laminate 10H shown in FIG. 9 was produced in the same manner as in Example 1H, except that the thickness of the protective layer was changed from 0.5 μm to 1 μm and no covering layer was provided.

[0416] (8.1.3) Example 3H A laminate 10H shown in FIG. 9 was produced in the same manner as in Example 1H, except that the thickness of the protective layer was changed from 0.5 μm to 3 μm.

[0417] (8.1.4) Example 4H Laminate 10H shown in FIG. 9 was produced in the same manner as Example 1H, with the following exceptions: no protective layer was provided; and instead of using the polyethylene film with a crystallinity of 27.6% described above as the intermediate layer, a polyethylene film with a thickness of 25 μm, a crystallinity of 58.5%, and a haze of 1.6% was used. This polyethylene film was subjected to corona treatment on both sides.

[0418] (8.1.5) Comparative Example 1H Laminate 10H shown in FIG. 9 was produced in the same manner as Example 1H, with the following exceptions: no protective layer was provided; instead of using the polyethylene film with a crystallinity of 58.5% described above as the base layer, a polyethylene film with a thickness of 25 μm, a crystallinity of 27.6%, and a haze of 21.5% was used; this polyethylene film was subjected to corona treatment on both sides; and instead of using the polyethylene film with a crystallinity of 27.6% described above as the intermediate layer, a polyethylene film with a thickness of 25 μm, a crystallinity of 58.5%, and a haze of 1.6% was used; this polyethylene film was subjected to corona treatment on both sides.

[0419] (8.2) Measurement and Evaluation Methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and the diffraction pattern obtained by this measurement was examined to see whether it had a sharp diffraction peak corresponding to the (110) plane.

[0420] The laminate was also evaluated for sealing property, heat resistance, visibility, drop strength, and recyclability. The evaluation methods for sealing property, heat resistance, visibility, drop strength, and recyclability are described below.

[0421] (8.2.1) Sealing performance evaluation method The sealing property was evaluated by the method explained in (1.2.1).

[0422] (8.2.2) Visibility evaluation method Visibility was evaluated using the method described in (1.2.2).

[0423] (8.2.3) Drop Strength Evaluation Method The drop strength was evaluated by the method described in (6.2.3).

[0424] (8.2.4) Recyclability evaluation method Recyclability was evaluated using the method described in (2.2.4). (8.3) Results The results of the above measurements and evaluations are summarized in Table 8 below.

[0425] [Table 8]

[0426] As shown in Table 8, all laminates in which the crystallinity of the base layer was 35% or higher had good heat resistance and visibility while being suitable for recycling. Furthermore, laminates in which the crystallinity of the base layer was 35% or higher, the crystallinity of the intermediate layer was less than 35%, and a protective layer were provided also had excellent sealing properties and drop strength. In contrast, laminates in which the crystallinity of the base layer was less than 35% and no protective layer was provided had insufficient sealing properties, heat resistance, and visibility. [Explanation of symbols]

[0427] 1...base material layer, 2...sealant layer, 3...adhesive layer, 3A...first adhesive layer, 3B...second adhesive layer, 4...printed layer, 5...gas barrier layer (inorganic compound layer), 6...protective layer, 7...coating layer, 8...intermediate layer, 10A1...laminate, 10A2...laminate, 10B...laminate, 10C...laminate, 10D...laminate, 10E...laminate, 10F...laminate, 10G...laminate, 10H...laminate, 100A...packaged article, 100B...packaged article, 100C...packaged article, 110A...packaged body, 110B...packaged body, 110C...packaged body, 110C1...container body, 110C2...mouth member, 110C3...lid body.

Claims

1. A laminate comprising a base layer, an adhesive layer, and a sealant layer in this order, and further comprising a gas barrier layer interposed between the base layer and the sealant layer, the substrate layer and the sealant layer comprise polyethylene; the substrate layer has a crystallinity of 40% or more, which is the ratio of a crystalline peak area to a total peak area, measured by a parallel beam method of X-ray diffraction in a diffraction angle range of 10° to 30°; The gas barrier layer is a laminate including a layer containing an ethylene-vinyl alcohol copolymer.

2. The laminate according to claim 1, wherein the crystallinity of the substrate layer is 75% or less.

3. The laminate according to claim 1, wherein the crystallinity of the substrate layer is 50% or more.

4. 2. The laminate according to claim 1, wherein the gas barrier layer includes an inorganic compound layer and a coating layer, and the coating layer is a layer containing the ethylene-vinyl alcohol copolymer.

5. 2. The laminate according to claim 1, further comprising an intermediate layer containing polyethylene interposed between the base layer and the sealant layer, wherein the intermediate layer has a crystallinity of 40% or more, which is the ratio of a crystalline peak area to a total peak area, measured by a parallel beam method of X-ray diffraction in a diffraction angle range of 10° to 30°.

6. The laminate according to claim 5, wherein the crystallinity of the intermediate layer is 75% or less.

7. The laminate according to claim 5 , wherein the crystallinity of the intermediate layer is 50% or more.

8. A packaging material comprising the laminate according to any one of claims 1 to 7.

9. A package comprising the packaging material of claim 8.

10. 10. The package according to claim 9, which is a stand-up pouch.

11. A packaged article comprising the package of claim 9 and contents contained therein.

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