Packaging materials, packaging bodies, and packaging articles

Abstract

To provide a laminate including polyethylene (PE) and having recyclability, the laminate excellent in thermostability and hardness and also to provide a package and a packed article including the same.SOLUTION: A laminate includes a substrate layer, an adhesive layer and a sealant layer in this order. The substrate layer and the sealant layer include polyethylene. In the substrate layer, a crystallinity index being a ratio of a crystal peak area to an entire peak area is 40% or more, measured by a parallel beam method of X-ray diffraction within a range of a diffraction angle 10° to 30°. However, the laminate includes a substrate, an image-forming layer, an adhesion layer, a vapor-deposited layer, an interlayer, an adhesion layer and a heat seal layer in this order. The substrate and respective intermediate layers are a three-layer co-extrusion oriented film in which a high density PE layer including high density PE with a density of 0.961 g / cm3, a medium density PE layer including medium density PE with a density of 0.941 g / cm3, and a high density PE layer including high density PE with a density of 0.961 g / cm3 are laminated in this order.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to laminates, packaging, and packaged articles. [Background technology]

[0002] Packaging materials used in packaging bags and the like require various properties depending on their intended use. Examples of required properties include heat resistance, transparency, heat sealability, strength, gas barrier properties, puncture resistance, visibility, suitability for bag making, suitability for printing, and suitability for transport. In order to adequately satisfy these various performance requirements, it has been common practice to use a composite 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 a circular economy, there has been a need for packaging materials with high recyclability. Generally, packaging materials are considered highly recyclable if the main resin content is 90% or more by mass. However, as mentioned above, conventional packaging materials are composed of different types of resin materials, and it is difficult to separate them into individual resin materials after use, making it impossible to recycle each material individually. Therefore, even if packaging made using conventional packaging materials is collected, the only option is to burn it and recover the heat, which is incompatible with the current global environmental protection efforts.

[0004] From a recyclability standpoint, technologies have been proposed to create packaging materials with a high polyethylene content and packaging films with the simplest possible layer structure (see, for example, Patent Documents 2 and 3). However, these have limitations, such as being restricted to light packaging applications due to factors like strength and heat resistance, and there is room for improvement to meet the various properties required depending on the application as a packaging material. [Prior art documents] [Patent Documents]

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a laminate containing polyethylene and having recyclability, which is excellent in heat resistance or strength, and a packaging body and a packaged article including the same.

Means for Solving the Problems

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

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

[0009] According to still 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 a ratio of the crystal peak area to the total peak area measured in the range of diffraction angles of 10° to 30° by the parallel beam method of X-ray diffraction.

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

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

[0012] According to yet another aspect of the present invention, a laminate relating to the above aspect is provided, in which the protective layer comprises a thermosetting resin.

[0013] According to yet another aspect of the present invention, a laminate is provided which is a biaxially oriented film as the base layer.

[0014] Alternatively, according to another aspect of the present invention, a laminate is provided which is a uniaxially oriented film as the base layer.

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

[0016] According to yet another aspect of the present invention, a laminate relating to any of the above aspects is provided, wherein the adhesive layer is gas barrier.

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

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

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

[0020] According to yet another aspect of the present invention, a packaging body is provided which includes a laminate relating to any of the above aspects.

[0021] According to yet another aspect of the present invention, a packaging body relating to the above aspect, which is a standing pouch, is provided.

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

[0023] According to the present invention, a laminate containing polyethylene and suitable for recycling is provided, which has excellent heat resistance and strength, as well as packaging and packaged articles containing the same. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 is a schematic cross-sectional view showing a laminate according to the first embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing one modified example of the laminate shown in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view showing a laminate according to a second embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing a laminate according to a third embodiment of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing a laminate according to the fourth embodiment of the present invention. [Figure 6] Figure 6 is a schematic cross-sectional view showing a laminate according to the fifth embodiment of the present invention. [Figure 7] Figure 7 is a schematic cross-sectional view showing a laminate according to the sixth embodiment of the present invention. [Figure 8] Figure 8 is a schematic cross-sectional view showing a laminate according to the seventh embodiment of the present invention. [Figure 9] Figure 9 is a schematic cross-sectional view showing a laminate according to the eighth embodiment of the present invention. [Figure 10]Figure 10 is a schematic diagram showing a packaged article according to the ninth embodiment of the present invention. [Figure 11] Figure 11 is a schematic diagram showing a packaged article according to the 10th embodiment of the present invention. [Figure 12] Figure 12 is a schematic diagram showing a packaged article according to the 11th embodiment of the present invention. [Modes for carrying out the invention]

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

[0026] Furthermore, the embodiments shown below illustrate configurations for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited by the material, shape, and structure of the components described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the claims described in the claims.

[0027] Elements with similar or identical functions are denoted by the same reference numerals in the drawings referenced below, and redundant explanations are omitted. Therefore, matters mentioned in one embodiment can also be applied to other embodiments unless otherwise specified. Furthermore, the drawings are schematic, and the relationships between dimensions in one direction and dimensions in another, and the relationships between the dimensions of one component and the dimensions of other components, etc., may differ from reality.

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

[0029] The base layer 1 and the sealant layer 2 contain polyethylene. The laminate 10A1 preferably contains 90% by mass or more polyethylene. Here, the percentage of polyethylene in the laminate refers to the ratio of the total amount of polyethylene to the total amount of resin material in each layer constituting the laminate. By setting the polyethylene percentage to 90% by mass or more, high recyclability can be achieved.

[0030] <1.2> Base material layer The base layer 1 contains polyethylene. Preferably, the base layer 1 is made of polyethylene. The base layer 1 has a crystallinity of 35% or more, which is the ratio of the crystal 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 base layer 1 is a value obtained by the measurement method described later.

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

[0032] Furthermore, having a crystallinity of 35% or higher in the substrate layer 1 reduces its elongation, improving its printability.

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

[0034] Other monomers include, for example, α-olefins. For example, α-olefins have a carbon number in the range of 3 to 20. Such α-olefins include, 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] Polyethylene may be a copolymer of ethylene and one of vinyl acetate or acrylic acid ester.

[0036] The base 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 / cm³. 3 In summary, medium-density polyethylene has a density of 0.930 g / cm³. 3 More than 0.942g / cm 3 It is less than 0.910 g / cm³, and low-density polyethylene has a density of 0.910 g / cm³. 3 More than 0.930g / cm 3 The density of linear low-density polyethylene is less than 0.910 g / cm³. 3 The above is 0.930cm 3 Ultra-low density polyethylene has a density of less than 0.910 g / cm³. 3 It is less than. The density is a value obtained using a method compliant with JIS K7112:1999.

[0038] The polyethylene contained in the base layer 1 may be biomass-derived polyethylene. For example, green polyethylene (manufactured by Braskem) can be used as biomass-derived polyethylene.

[0039] Alternatively, the polyethylene contained in the base layer 1 may be polyethylene recycled by mechanical recycling. Here, mechanical recycling is a method of decontaminating polyethylene film by crushing the collected polyethylene film, then washing the crushed film with alkali to remove dirt and foreign matter from the film surface, and finally drying it at high temperature and under reduced pressure to diffuse any contaminants remaining inside the film. Alternatively, the polyethylene contained in the base layer 1 may be polyethylene recycled through 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 an unstretched film or a stretched film. It is preferable that the base layer 1 be 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 obtained: Specifically, it exhibits particularly excellent heat resistance and strength. 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 oriented film or a biaxially oriented film. Using a uniaxially oriented film as the base layer 1 further improves the heat resistance during bag making, i.e., the sealing performance described later. Using a biaxially oriented film as the base layer 1 improves the drop strength of the packaged article using the laminate 10A1 as the packaging material.

[0043] Furthermore, whether a stretched film is uniaxially oriented or biaxially oriented can be determined by performing an 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 on the film surface.

[0044] When a polymer film is uniaxially stretched, a higher-order structure called a shish-kebab structure appears. The shish-kebab structure consists of shish structures, which are elongated chain crystals, and kebab structures, which are lamellar crystals. In uniaxially stretched films, these higher-order structures are arranged with a high degree of order, and therefore, the X-ray diffraction pattern obtained by the above measurement on a uniaxially stretched film will contain sharp diffraction peaks. In other words, when the above measurement is performed on a uniaxially stretched film, clear diffraction peaks appear. Note that "clear diffraction peaks" refers to diffraction peaks with a full width at half maximum of less than 10°.

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

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

[0047] The film can be manufactured by known methods such as the casting method or the inflation method. Alternatively, a multilayer polyethylene film obtained by co-extruding polyethylenes of different densities can be used as the base layer 1. The stretched film can be obtained, for example, by stretching a film obtained by forming polyethylene using the T-die method or the inflation method. The base layer 1 may be a uniaxially oriented film or a biaxially oriented film.

[0048] The haze of the base layer 1 is preferably 20% or less, and more preferably 10% or less. The haze value is 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. For example, the thickness of the base layer 1 may be 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 tends to be low. Also, if the base layer 1 is too thick, the processability of the laminate 10A1 tends to decrease.

[0050] It is preferable that the base layer 1 is surface-treated. This treatment can improve the adhesion between the base layer 1 and the layer adjacent to it.

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

[0052] The base layer 1 may further contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants, ultraviolet 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. In one example, the base layer 1 is made of polyethylene. In another example, the base layer 1 is made of polyethylene and an additive.

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

[0055] As described above, the base layer 1 has a crystallinity of 35% or more. The printed layer 4 is located on the inner surface side of the base layer 1, and the patterns, characters, and other images displayed by the printed layer 4 can be viewed with good visibility. From this viewpoint, the crystallinity of the base layer 1 is preferably 40% or more, and more preferably 50% or more. For example, the crystallinity is in the range of 50% to 75%. Furthermore, a polyethylene-containing layer with a crystallinity of 35% or more also exhibits excellent puncture strength, as will be explained 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 and therefore contains both crystalline and amorphous regions. Polyethylene with a high degree of crystallinity has a high proportion of crystalline regions. Since these crystalline regions govern the elastic portion of the resin's viscoelastic behavior, a higher degree of crystallinity improves the rigidity of the film.

[0057] Due to this viscoelastic behavior, in films with a high degree of crystallinity, the strain associated with the plastic deformation of the resin is also greater. As a result, the deformation of the resin is suppressed in response to the strain generated by an instantaneous impact applied to the film, making it less likely to break. Therefore, the laminate 10A1, which has a base material 1 containing polyethylene and a degree of crystallinity of 35% or higher, has excellent resistance to instantaneous impact, and packaged items using the laminate 10A1 as a packaging material are less likely to be damaged (broken) by dropping. In other words, it has excellent resistance to bag breakage.

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

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

[0060] First, the X-ray diffraction pattern of substrate layer 1 is obtained using a wide-angle X-ray diffractometer manufactured by Rigaku Corporation, by out-of-plane measurement, scanning the diffraction angle range of 10° to 30° with a 2θ / θ scan. Characteristic X-rays CuKα are used, and the X-rays are parallelized using a multilayer mirror before being incident on substrate layer 1. A scintillation detector with a flat-plate 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 sum of these areas is calculated as the degree of crystallinity. If the base layer 1 has multiple layers, the degree of crystallinity of one of the outermost surfaces of the base layer 1 is measured.

[0062] When the substrate layer 1 is a polyethylene film, scanning in the diffraction angle range of 10° to 30° reveals two sharp crystalline component peaks corresponding to the (110) and (200) planes, and a broad amorphous component halo pattern. By separating and analyzing these, and calculating the area of ​​the crystalline component peaks and the area of ​​the amorphous component halo pattern, the degree of crystallinity can be determined from the following equation (1).

[0063] Crystallinity = Peak area of ​​crystalline component / (Peak area of ​​crystalline component + Halo pattern area of ​​amorphous component) ... (1) While the focusing method is known as an X-ray diffraction method other than the parallel beam method, with the focusing method, when the sample has surface irregularities such as those of a resin film, the measurement results are easily affected by the positional displacement of the measurement surface, such as peak broadening. In contrast, with the parallel beam method, even when the sample has surface irregularities, the positional displacement of the measurement surface has little effect on the measurement results.

[0064] On the other hand, the substrate layer 1 is preferably uniaxially oriented or biaxially oriented, but as mentioned above, an in-plane method using X-ray diffraction can be used to distinguish between them. In this in-plane method, the X-ray incidence angle θ and the angle 2θ at which the diffracted X-rays are detected by the detector are fixed to the angles θ and 2θ at which diffraction peaks corresponding to a specific crystal plane are detected in the out-of-plane method described above, for example, the diffraction peak corresponding to the (110) plane of the polyethylene film, and in this state, a diffraction pattern is obtained by scanning the film to be measured in the in-plane direction.

[0065] When in-plane measurement is performed on a uniaxially oriented film stretched uniaxially in the mechanical direction (MD), if the MD direction is defined as 0°, a diffraction pattern can be obtained in which sharp diffraction peaks corresponding to the (110) plane are located at angles 2θ of approximately ±90°. On the other hand, in the case of a biaxially oriented film, the higher-order structure obtained by uniaxial stretching is disturbed by the second stretching, and the anisotropy is reduced, so a diffraction pattern with sharp diffraction peaks corresponding to the (110) plane cannot be obtained. Therefore, in-plane measurement can be cited as one method for distinguishing between uniaxially oriented films and biaxially oriented 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. As the polyethylene, for example, the polyethylene described 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 low-density polyethylene (VLDPE), and more preferably linear low-density polyethylene.

[0067] From an environmental perspective, it is preferable that the polyethylene used is 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 additives.

[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, the contents are easily visible when it is used as packaging. When the laminate 10A1 has an opaque sealant layer 2, the contents do not obstruct the visibility of the image displayed by the printed layer 4 when it is used as packaging. In particular, a white sealant layer 2 improves the visibility of the image displayed by the printed layer 4.

[0070] The thickness of the sealant layer 2 can be set appropriately considering the shape of the packaging bag to be manufactured and the mass of the contents to be contained, but for example it can be 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 substrate layer 1 facing the sealant layer 2, that is, on the back surface of the substrate layer 1. The position of the printed layer 4 is not limited. That is, the printed layer 4 may be provided on the surface of the substrate layer 1, or at any position between the substrate layer 1 and the sealant layer 2. For example, if the laminate 10A1 further includes an intermediate layer described later, the printed layer 4 may be provided on any surface 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 in the printing layer 4 is not particularly limited, as long as it has adhesion to polyethylene. The printing layer 4 is composed of an ink in which various pigments, extender pigments, plasticizers, drying agents, and stabilizers are added to conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride. It is preferable to use biomass-derived ink as the printing ink. As for the printing method, 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 can be used. Light-shielding inks can also be preferably used. Examples include white, black, silver, and sepia inks.

[0074] <1.5>Adhesive layer The adhesive layer 3 bonds the substrate layer 1, on which the printed 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. Furthermore, the adhesive may be a solvent-free adhesive or a solvent-based adhesive.

[0075] Examples of adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives such as polyamine-based adhesives, urethane-based adhesives, rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives. Adhesives containing biomass components can also be preferably used. Preferably, the adhesive is a polyamine-based adhesive or a urethane-based adhesive having gas barrier properties. Specific examples of gas barrier adhesives include "Maxieve" manufactured by Mitsubishi Gas Chemical Company 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 phosphate-modified compound. Such an adhesive layer 3 can further improve the oxygen barrier and water vapor barrier properties 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 it on the sealant layer 2 using conventionally known methods such as the direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, fontein method, and transfer roll coating method.

[0079] <1.6> Effect The laminate 10A1 described above has excellent heat resistance and recyclability. This will be explained below.

[0080] The manufacturing process of packaging bags generally involves bringing the sealant layers of a laminate into contact with each other, and then applying pressure and heat to the contact area by clamping it with a jig, thereby heat-sealing the contact point. The jig of the heat-sealing machine becomes hot, and the surface of the base layer that is in direct contact with the jig is exposed to high temperatures. As a result, if polyethylene, which has poor heat resistance, is used as the base layer, problems such as the surface of the base layer being affected by the heat and sticking to the jig may occur. Therefore, conventional laminates using polyethylene as the base layer have had the problem of having a narrow range of optimal bag-making temperatures and poor productivity.

[0081] The inventors measured the degree of crystallinity of various polyethylenes and found that when the degree of crystallinity of the base layer 1 is 35% or higher, the base layer 1 exhibits excellent heat resistance, and therefore the laminate 10A1 also exhibits excellent heat resistance, and in particular, good heat sealability is achieved. In the laminate 10A1, polyethylene, which is generally said to have poor heat resistance, is used as the base layer 1. However, by setting the degree of crystallinity of the base layer 1 to 35% or higher, the temperature range for heat sealing performed for bag making is expanded, and packaging can be manufactured without causing a decrease in productivity, and furthermore, without causing appearance defects due to shrinkage of the sealed part.

[0082] Since the laminate 10A1, which has excellent heat resistance, uses the degree of crystallinity of the base layer 1 as an indicator, the surface properties of the laminate 10A1 can be easily measured and understood, and the quality as a packaging material can be easily stabilized.

[0083] Furthermore, since the laminate 10A1 comprises a base layer 1 and a sheet heel layer, which are mainly composed of polyethylene, it is easy to achieve a polyethylene content of 90% by mass or more. Therefore, the laminate 10A1 also has excellent recyclability.

[0084] <1.7> Variant The laminate 10A1 can undergo various deformations. Figure 2 is a schematic cross-sectional view showing a modified example of the laminate shown in Figure 1. The laminate 10A2 shown in Figure 2 is the same as the laminate 10A1 except that it further includes an inorganic compound layer 5 interposed between the substrate layer 1 and the printed layer 4. The inorganic compound layer 5 is a thin film made of an inorganic compound, such as an inorganic oxide like aluminum oxide or silicon oxide, and functions as a gas barrier layer that suppresses the permeation of oxygen and water vapor.

[0085] <Inorganic compound layer> The inorganic compound layer 5 may be formed by coating, or by depositing 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 viewpoint of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, considering cost, the metal oxide is selected from aluminum oxide and silicon oxide. Moreover, from the viewpoint of excellent tensile stretchability 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] Because metal oxide vapor-deposited films are transparent, they have the advantage of being less likely to cause users to mistakenly believe that metal foil is used when handling laminated packaging materials, compared to vapor-deposited films made of metal.

[0088] The thickness of the vapor-deposited aluminum oxide film is preferably between 5 nm and 30 nm. A thickness of 5 nm or more provides sufficient gas barrier properties. A thickness of 30 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 30 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 7 nm or more and 15 nm is more preferable for the vapor-deposited aluminum oxide film.

[0089] The thickness of the silicon dioxide vapor-deposited film is preferably between 10 nm and 50 nm. A thickness of 10 nm or more provides sufficient gas barrier properties. A thickness of 50 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 50 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 20 nm or more and 40 nm is more preferable for the silicon dioxide vapor-deposited film.

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

[0091] In the vacuum deposition methods described above, resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD) are particularly preferred. However, considering productivity, vacuum deposition is currently the most superior method. For the heating means in vacuum deposition, it is preferable to use one of the following methods: electron beam heating, resistance heating, or induction heating.

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

[0093] <Coating layer> Furthermore, as will be explained 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. In the following, the inorganic compound layer 5 may be referred to as the gas barrier layer, or 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 exhibits excellent heat resistance. Furthermore, since the inorganic compound layer 5 is substantially transparent, even if the inorganic compound layer 5 is placed between the substrate layer 1 and the printing layer 4, the image displayed by the printing layer 4 can be seen from the surface side. In addition, the laminate 10A2 also exhibits excellent recyclability.

[0095] Furthermore, to provide light-shielding properties, a metal vapor-deposited layer may be provided between the substrate layer 1 and the sealant layer 2 in the laminates 10A1 and 10A2. If the laminate further includes an intermediate layer, which will be described later, a metal vapor-deposited layer may be provided on any surface of the intermediate layer. An aluminum vapor-deposited layer can be given as an example of a metal vapor-deposited layer.

[0096] As previously mentioned, the sealant layer 2 may be opaque, and the base layer 1 may also be opaque. For example, the base layer 1 may be white. If 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 Figure 3 is a schematic cross-sectional view showing a laminate according to a second embodiment of the present invention. The laminate 10B shown in Figure 3 comprises a protective layer 6, a base layer 1, a gas barrier layer 5, a printing layer 4, an adhesive layer 3, and a sealant layer 2 in this order. The gas barrier layer 5 included in the laminate 10B consists of an inorganic compound layer, or an inorganic compound layer and a coating layer. The laminate 10B is the same as the laminate 10A1 except that it further includes a protective layer 6 provided on the surface of the base layer 1 and a gas barrier layer 5 interposed between the base layer 1 and the printing layer 4. The base layer 1, printing layer 4, adhesive layer 3, and sealant layer 2 of 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 its 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 include polyurethane resin, polyester resin, polyamide resin, polyamide-imide 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.

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

[0100] Examples of water-soluble polymers include polyvinyl alcohol-based polymers, polysaccharides such as starch, methylcellulose, and carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. In one embodiment, the protective layer 6 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that can be contained in the coating layer as the gas barrier layer 5 described later.

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

[0102] Further, the protective layer 6 preferably further contains, as an organometallic compound, 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 its hydrolyzate.

[0103] In one form, the protective layer 6 can be formed using a coating liquid for forming a coating layer as the gas barrier layer 5 described later. Also, 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 that used for forming the coating layer.

[0104] The protective layer 6 reduces thermal damage during heat sealing on the surface of the laminate. By having the protective layer 6 with excellent heat resistance on the outermost layer, the laminate 10B ensures heat sealability and productivity while using a polyethylene resin with poor heat resistance as a base material.

[0105] The thickness of the protective layer 6 is preferably within the 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 resin cured 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 consists of an inorganic compound layer, or an inorganic compound layer and a coating layer. When the gas barrier layer 5 consists of an inorganic compound layer and a coating layer, it is preferable that the inorganic compound layer and the coating layer are laminated in that order from the side of the substrate layer 1. The gas barrier layer 5 may be formed by coating, or it may be formed by vapor deposition of an inorganic compound. The inorganic compound layer is the same as the inorganic compound layer described in the modified example of Embodiment 1.

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

[0108] The coating layer may be an organic-inorganic composite layer comprising, for example, a metal alkoxide, a hydrolysate of a metal alkoxide, and at least one of the reaction products of a metal alkoxide or a hydrolysate of a metal alkoxide, and a water-soluble polymer. This organic-inorganic composite layer may further comprise a silane coupling agent, a hydrolysate of a silane coupling agent, and at least one of the reaction products of a silane coupling agent or a hydrolysate of a silane coupling agent.

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

[0110] The total content of metal alkoxides, their hydrolysates, or their reaction products in the coating solution used to form an 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 properties. Furthermore, the total content of metal alkoxides, their hydrolysates, or their reaction products in the above coating solution 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 include polyvinyl alcohol-based polymers, polysaccharides such as starch, methylcellulose, and carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving oxygen gas barrier properties, it is preferable that the water-soluble polymer 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 of acetate groups remaining, or it may have only a few percent of acetate groups remaining.

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

[0114] Examples of silane coupling agents used in organic-inorganic composite layers include silane coupling agents having organic functional groups. Such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidooxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. A silane coupling agent selected from these, its hydrolysate, and their reaction products can be used individually or in combination of two or more.

[0115] It is preferable to use a silane coupling agent that has an epoxy group as an organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidooxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Silane coupling agents having an epoxy group may also have organic functional groups other than the epoxy group, such as a vinyl group, an amino group, a methacrylic group, or a ureil group. One of the silane coupling agents selected from these, their hydrolysates, and their reaction products can be used individually or in combination of two or more.

[0116] Silane coupling agents having organic functional groups, their hydrolysates, or their reaction products can further improve the oxygen barrier properties of the coating layer and the adhesion to adjacent layers through the interaction of their organic functional groups with the hydroxyl groups of water-soluble polymers. In particular, when the silane coupling agent, its hydrolysate, or their reaction products have epoxy groups and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction between the epoxy groups and the hydroxyl groups of PVA can further improve the oxygen barrier properties and the adhesion to adjacent layers.

[0117] The total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating solution used to form the organic-inorganic composite layer may be 1% by mass or more, or 2% by mass or more, from the viewpoint of oxygen barrier properties. Furthermore, the total content of the silane coupling agent, its hydrolysate, and their reaction products in the above coating solution may be 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, and more preferably 100 nm to 500 nm. When the thickness of the gas barrier coating layer is 50 nm or more, it tends to be possible to obtain more sufficient gas barrier properties, and when it is 1000 nm or less, it tends to be possible to maintain sufficient flexibility.

[0119] It is preferable that the gas barrier layer 5 is subjected to the surface treatment described above. This improves the adhesion between the gas barrier layer 5 and the adjacent layer. Furthermore, nanocomposites may be used as the material for the gas barrier layer 5.

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

[0121] <Anchor Coat Layer> The laminate 10B may further include an anchor coat layer (not shown) on the main surface 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 coat agents include polyester polyurethane resin and polyether polyurethane resin. From the viewpoint of heat resistance and interlayer adhesion strength, polyester polyurethane resin is preferred as the anchor coat agent.

[0122] The proportion of polyethylene in the laminate 10B is, for example, 90% by mass or more. This ensures that the laminate 10B is constructed as a highly recyclable monomaterial.

[0123] <2.4> Effect Laminate 10B, like laminate 10A1, comprises a base layer 1 containing polyethylene and having a degree of crystallinity within the above range. Therefore, laminate 10B, like laminate 10A1, has excellent heat resistance.

[0124] Furthermore, the laminate 10B includes a protective layer 6 on its outermost surface. As described above, the protective layer 6 reduces thermal damage to the surface of the laminate during heat sealing. Therefore, the laminate 10B can achieve even better heat resistance, and in particular, better heat sealability. Accordingly, by adopting the above configuration for the laminate 10B, the temperature range for heat sealing performed for bag making is expanded, and it becomes even less likely for productivity to decrease and for defects in appearance due to shrinkage of the sealed part to occur.

[0125] Furthermore, since the aforementioned 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 substrate layer 1 and the printing layer 4, the image displayed by the printing layer 4 can be seen from the surface side. In other words, laminate 10B has excellent heat resistance and recyclability.

[0126] <3> Third Embodiment <3.1> Laminate Figure 4 is a schematic cross-sectional view showing a laminate according to a third embodiment of the present invention. The laminate 10C shown in Figure 4 comprises 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 the laminate 10B of the second embodiment described above, including the inorganic compound layer and the coating layer from the base layer 1 side as a 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 of 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> Laminate 10C, like laminate 10B according to the second embodiment, may further include an anchor coat layer (not shown) on the main surface of the base layer 1 that faces the inorganic compound layer 5. This improves the adhesion of the inorganic compound layer 5. Examples of anchor coat agents include polyester polyurethane resin and polyether polyurethane resin. From the viewpoint of heat resistance and interlayer adhesion strength, polyester polyurethane resin is preferred as the anchor coat agent.

[0128] <3.3> Effects Since laminate 10C has the same layer structure as laminate 10B, it produces the same effects as laminate 10B.

[0129] <4> Fourth Embodiment <4.1> Laminate Figure 5 is a schematic cross-sectional view showing a laminate according to the fourth embodiment of the present invention. The laminate 10D shown in Figure 5 comprises a base layer 1, a first adhesive layer 3A, a gas barrier layer 5, an intermediate layer 8, a printing layer 4, a second adhesive layer 3B, and a sealant layer 2 in this order. Laminate 10D is the same as laminate 10B except for the following: Laminate 10D further includes an intermediate layer 8. Also, laminate 10D includes a first adhesive layer 3A and a second adhesive layer 3B instead of adhesive layer 3. The base layer 1, printing layer 4, and sealant layer 2 of 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 properties and water vapor barrier properties 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 of these. When microwave heating by a microwave oven is anticipated, the gas barrier layer 5 is preferably an inorganic oxide layer, a resin-containing layer, or a combination of these.

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

[0132] Examples of inorganic oxides that can be used include silicon dioxide, boron oxide, or 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 solution containing resins such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, and epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may be added to this coating solution.

[0134] When forming the resin-containing layer by melt molding, for example, extrusion molding techniques such as T-die or inflation can be used. In melt molding, for example, the above-mentioned resin or a mixture of the above-mentioned 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. Then, this film or sheet is laminated with the intermediate layer 8.

[0135] The thickness of the gas barrier layer 5 is preferably in the range of 1 nm to 200 nm if it is an inorganic oxide layer. If the thickness is 1 nm or more, excellent oxygen barrier properties and water vapor barrier properties can be obtained. If the thickness is 200 nm or less, manufacturing costs can be kept low, and cracks due to external forces such as bending and pulling are less likely to occur, thus suppressing deterioration of barrier properties. If it is a resin-containing layer, for example, 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. If the thickness is 0.2 μm or more, excellent oxygen barrier properties and water vapor barrier properties can be obtained. If the thickness is 10 μm or less, manufacturing costs can be kept low.

[0136] It is preferable that the gas barrier layer 5 is subjected to the surface treatment described above. This improves the adhesion between the gas barrier layer 5 and the adjacent layer. Furthermore, nanocomposites may be used as the material for the gas barrier layer 5.

[0137] <4.3> Middle Class The intermediate layer 8 contains polyethylene. As the polyethylene, for example, the polyethylene described above for the polyethylene contained in the base layer 1 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 also contain the additives mentioned above.

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

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

[0141] An intermediate layer 8 with a crystallinity of 35% or higher enhances the strength of the laminate 10D, particularly its puncture strength. Therefore, the laminate 10D has excellent strength, especially puncture strength. Laminates with a high proportion of polyethylene are less rigid compared to other laminates, and therefore are more likely to be bent when used as packaging material. Increased bending increases the likelihood of pinhole formation, but the laminate 10D, with its excellent puncture strength, is less prone to developing pinholes. From this viewpoint, it is preferable that the intermediate layer 8 with a crystallinity of 35% or higher is 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, it may be white.

[0145] The intermediate layer 8 can be manufactured by known methods such as the casting method or the inflation method. Alternatively, a multilayer polyethylene film obtained by co-extruding polyethylenes of different densities can be used as the intermediate layer 8. The stretched film can be obtained, for example, by stretching a film obtained by forming a polyethylene film using the T-die method or the inflation method.

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

[0147] <4.4>Adhesive layer The adhesives used to form the first adhesive layer 3A and the second adhesive layer 3B may be the same or different. The adhesives used to form 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. Furthermore, the adhesive may be a solvent-free adhesive or a solvent-based adhesive.

[0149] Examples of adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives such as polyamine-based adhesives, urethane-based adhesives, rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives. Adhesives containing biomass components can also be preferably used. Preferably, the adhesive is a polyamine-based adhesive or a urethane-based adhesive that has gas barrier properties.

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

[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 them on the substrate layer 1 using conventionally known methods such as the direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, fontein method, and transfer roll coating method.

[0153] In Figure 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] Furthermore, although the printed layer 4 is provided between the intermediate layer 8 and the second adhesive layer 3B in Figure 5, the printed layer 4 may be provided at any position between the substrate layer 1 and the sealant layer 2. It is preferable that the printed layer 4 is provided between the first adhesive layer 3A and the substrate layer 1. In this case, when the laminate 10B is observed from the substrate layer 1 side, the pattern displayed by the printed layer 4 is easily and clearly visible.

[0155] Furthermore, an anchor coat layer may be formed on the main surface of the substrate layer 1 that faces the first adhesive layer 3A. Also, the gas barrier layer 5 and the printing layer 4 may be omitted.

[0156] The proportion of polyethylene in the laminate 10D is, for example, 90% by mass or more. This ensures that the laminate 10D is constructed as a highly recyclable monomaterial.

[0157] <4.5> Effect The laminate 10D described above, like the laminate 10A1, comprises a base layer 1 containing polyethylene and having a degree of crystallinity within the above range. Therefore, the laminate 10D, like the laminate 10A1, has excellent heat resistance.

[0158] Furthermore, the laminate 10D includes an intermediate layer 8 whose degree of crystallinity is within the above range. This intermediate layer 8 enhances the strength of the laminate 10D, particularly its puncture strength. Therefore, the laminate 10D has excellent strength, especially puncture strength.

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

[0160] Furthermore, as mentioned above, laminates with a high polyethylene content are less rigid compared to other laminates, and therefore are more likely to be bent when used as packaging material. Increased bending increases the likelihood of pinhole formation, but laminate 10D, which has excellent puncture strength, is less prone to developing 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, according to the method specified in JIS Z1707:2019 "General Rules for Plastic Films for Food Packaging". 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 until the needle penetrates is measured. This measurement is performed multiple times, and the arithmetic mean of the maximum forces is obtained as the puncture strength.

[0162] <5> Fifth Embodiment <5.1> Laminate Figure 6 is a schematic cross-sectional view showing a laminate according to the fifth embodiment of the present invention. The laminate 10E shown in Figure 6 comprises a protective layer 6, a base layer 1, a printing 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. Laminate 10E is the same as laminate 10D except for the following: Laminate 10E further includes a protective layer 6. In laminate 10E, the inorganic compound layer 5 is interposed between the second adhesive layer 3B and the intermediate layer 8. In laminate 10E, the printing layer 4 is interposed between the base layer 1 and the first adhesive layer 3A. The base layer 1, printing layer 4, first adhesive layer 3A, intermediate layer 8, second adhesive layer 3B, and sealant layer 2 of 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 include polyurethane resin, polyester resin, polyamide resin, polyamide-imide 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.

[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 alcohol-based polymers, polysaccharides such as starch, methylcellulose, and carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. In one embodiment, the protective layer 6 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that can be contained in the coating layer as the gas barrier layer 5 described later.

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

[0167] Furthermore, it is preferable that the protective layer 6 further contains, as an 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 solution used to form a coating layer, which will be described later as a gas barrier layer 5. Furthermore, if 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 solution used to form that coating layer.

[0169] The laminate 10E, by having a protective layer 6 with excellent heat resistance on its outermost surface, ensures heat sealability and productivity even though polyethylene resin, which has poor heat resistance, is used as the base material.

[0170] The thickness of the protective layer 6 is preferably in the 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 resin cured 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 properties and water vapor barrier properties of the laminate 10E. The gas barrier layer 5 consists of an inorganic compound layer or an inorganic compound layer and a coating layer. When the gas barrier layer 5 consists of an inorganic compound layer and a coating layer, it is preferable that the inorganic compound layer and the coating layer are laminated in that order from the side of the intermediate layer 8.

[0172] The gas barrier layer 5 may be formed by coating, or by depositing 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 viewpoint of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, considering cost, the metal oxide is selected from aluminum oxide and silicon oxide. Moreover, from the viewpoint of excellent tensile stretchability during processing, the use of silicon oxide as the metal oxide is even more preferable. By making the inorganic compound layer contained in the gas barrier 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 10E.

[0174] Because metal oxide vapor-deposited films are transparent, they have the advantage of being less likely to cause users to mistakenly believe that metal foil is used when handling laminated packaging materials, compared to vapor-deposited films made of metal.

[0175] The thickness of the vapor-deposited aluminum oxide film is preferably between 5 nm and 30 nm. A thickness of 5 nm or more provides sufficient gas barrier properties. A thickness of 30 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 30 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 7 nm or more and 15 nm is more preferable for the vapor-deposited aluminum oxide film.

[0176] The thickness of the silicon dioxide vapor-deposited film is preferably between 10 nm and 50 nm. A thickness of 10 nm or more provides sufficient gas barrier properties. A thickness of 50 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 50 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 20 nm or more and 40 nm is more preferable for the silicon dioxide vapor-deposited film.

[0177] Inorganic compound layers can be formed, for example, by vacuum deposition. Vacuum deposition can utilize either physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition include, but are not limited to, vacuum evaporation, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD (Chemical Vapor Deposition), plasma CVD, and photoCVD.

[0178] In the vacuum deposition methods described above, resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD) are particularly preferred. However, considering productivity, vacuum deposition is currently the most superior method. For the heating means in vacuum deposition, it is preferable to use one of the following methods: electron beam heating, resistance heating, or induction heating.

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

[0180] The coating layer may be an organic-inorganic composite layer comprising, for example, a metal alkoxide, a hydrolysate of a metal alkoxide, and at least one of the reaction products of a metal alkoxide or a hydrolysate of a metal alkoxide, and a water-soluble polymer. This organic-inorganic composite layer may further comprise a silane coupling agent, a hydrolysate of a silane coupling agent, and at least one of the reaction products of a silane coupling agent or a hydrolysate of a silane coupling agent.

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

[0182] The total content of metal alkoxides, their hydrolysates, or their reaction products in the coating solution used to form an 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 properties. Furthermore, the total content of metal alkoxides, their hydrolysates, or their reaction products in the above coating solution 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 include polyvinyl alcohol-based polymers, polysaccharides such as starch, methylcellulose, and carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving oxygen gas barrier properties, it is preferable that the water-soluble polymer 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 of acetate groups remaining, or it may have only a few percent of acetate groups remaining.

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

[0186] Examples of silane coupling agents used in organic-inorganic composite layers include silane coupling agents having organic functional groups. Such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidooxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. A silane coupling agent selected from these, its hydrolysate, and their reaction products can be used individually or in combination of two or more.

[0187] It is preferable to use a silane coupling agent that has an epoxy group as an organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidooxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Silane coupling agents having an epoxy group may also have organic functional groups other than the epoxy group, such as a vinyl group, an amino group, a methacrylic group, or a ureil group. One of the silane coupling agents selected from these, their hydrolysates, and their reaction products can be used individually or in combination of two or more.

[0188] Silane coupling agents having organic functional groups, their hydrolysates, or their reaction products can further improve the oxygen barrier properties and adhesion to adjacent layers of an organic-inorganic composite layer through the interaction of their organic functional groups with the hydroxyl groups of a water-soluble polymer. In particular, when the silane coupling agent, its hydrolysate, or their reaction products have epoxy groups and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction between the epoxy groups and the hydroxyl groups of PVA can further improve the oxygen barrier properties and adhesion to adjacent layers.

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

[0190] It is preferable that the gas barrier layer 5 is subjected to the surface treatment described above. This improves the adhesion between the gas barrier layer 5 and the adjacent layer. Furthermore, nanocomposites may be used as the material for the gas barrier layer 5.

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

[0192] <Anchor Coat Layer> The laminate 10E may further include an anchor coat layer (not shown) on the side of the intermediate layer 8 where the gas barrier layer 5 is formed. Alternatively, the laminate 10E may further include an anchor coat layer (not shown) on the main surface of the base layer 1 facing 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 oxides. Examples of anchor coat agents include polyester polyurethane resins and polyether polyurethane resins. From the viewpoint of heat resistance and interlayer adhesion strength, polyester polyurethane resins are preferred as the anchor coat agent.

[0193] In Figure 6, the laminate 10E includes a printed layer 4 between the base layer 1 and the first adhesive layer 3A, but the printed layer 4 may be included at any position between the protective layer 6 and the sealant layer 2. Since the base layer 1 and the 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 in which the printed layer 4 is included. For example, it is preferable for the printed layer 4 to 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] Furthermore, in Figure 6, the laminate 10E includes a gas barrier layer 5 on the surface of the intermediate layer 8 facing the sealant layer 2, but the laminate 10E may also include a gas barrier layer 5 on the surface of the intermediate layer 8 facing the substrate layer 1.

[0195] The proportion of polyethylene in the laminate 10E is, for example, 90% by mass or more. This ensures that the laminate 10E is constructed as a highly recyclable monomaterial.

[0196] <5.4> Effect The laminate 10E described above, like the laminate 10A1, is equipped with a polyethylene-containing layer having a degree of crystallinity within the above range as the base layer 1. Therefore, the laminate 10E, like the laminate 10A1, has excellent heat resistance.

[0197] Furthermore, the laminate 10E 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, and in particular, better heat sealability. Accordingly, by adopting the above configuration for the laminate 10E, the temperature range for heat sealing performed for bag making is expanded, and a decrease in productivity becomes even less likely.

[0198] Furthermore, the laminate 10E includes an intermediate layer 8 whose degree of crystallinity is within the above range. This intermediate layer 8 enhances the strength of the laminate 10E, particularly its puncture strength. Therefore, the laminate 10E has excellent strength, especially puncture strength.

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

[0200] Furthermore, laminates with a high polyethylene content are less rigid compared to other laminates, and therefore are more likely to be bent when used as packaging material. Increased bending increases the likelihood of pinhole formation, but laminate 10E, which has excellent puncture strength, is less prone to developing pinholes.

[0201] Furthermore, since the base layer 1 and the intermediate layer 8 are transparent in the laminate 10E, for example, regardless of whether the printed layer 4 is located between the base layer 1 and the sealant layer 2, the pattern displayed by the printed layer 4 is clearly visible when observed from the protective layer 6 side. In addition, the contents of a packaged article containing the laminate 10E described above are highly visible.

[0202] <6> Sixth Embodiment <6.1> Laminate Figure 7 is a schematic cross-sectional view showing a laminate according to the sixth embodiment of the present invention. The laminate 10F shown in Figure 7 comprises a protective layer 6, a base layer 1, a printing 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. Laminate 10F is the same as laminate 10E except that the crystallinity of the intermediate layer 8 is less than 35%. Among the layers comprising laminate 10F, the layers other than the intermediate layer 8, namely the protective layer 6, base layer 1, printing layer 4, first adhesive layer 3A, gas barrier layer 5, second adhesive layer 3B, and sealant layer 2, can be those described in the fifth embodiment.

[0203] <6.2> Middle Class The intermediate layer 8 contains polyethylene. As the polyethylene, for example, the polyethylene described above for the polyethylene contained in 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 also contain the additives mentioned above.

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

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

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

[0208] In this embodiment, an intermediate layer with a crystallinity of 35% or higher may be used. When an intermediate layer with a crystallinity of 35% or higher is used, the strength of the laminate 10, particularly its puncture strength, can be improved. A stretched film is preferred as the intermediate layer with a crystallinity of 35% or higher.

[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 using known methods such as the casting method and inflation method described above. It is also possible to use a multilayer polyethylene film, which is produced by co-extruding polyethylenes of different densities, as the base layer 1.

[0211] <Anchor Coat Layer> The laminate 10F may further include an anchor coat layer (not shown) on the side of the intermediate layer 8 where 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. As the anchor coat layer, the one described in the fifth embodiment can be used.

[0212] In Figure 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] Furthermore, in Figure 7, the printed layer 4 is provided between the substrate 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 more clearly visible.

[0214] Furthermore, 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. This ensures that the laminate 10F is constructed as a highly recyclable monomaterial.

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

[0217] Furthermore, the laminate 10F 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, and in particular, better heat sealability. Accordingly, by adopting the above configuration for the laminate 10F, the temperature range for heat sealing performed for bag making is expanded, and a decrease in productivity becomes even less likely.

[0218] Furthermore, the laminate 10F includes an intermediate layer 8 whose degree of crystallinity is within the above range. This intermediate layer 8 enhances the strength of the laminate 10F, particularly its drop strength. That is, in the laminate 10F, when used in packaging, the intermediate layer 8 located inside 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, packaged items using the laminate 10F as a packaging material are less likely to be damaged (broken) by drops. Consequently, the laminate 10F has excellent strength, particularly drop strength.

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

[0220] <7> Seventh Embodiment <7.1> Laminate Figure 8 is a schematic cross-sectional view showing a laminate according to the seventh embodiment of the present invention. The laminate 10G shown in Figure 8 comprises a protective layer 6, a base layer 1, a printing 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 case in the laminate 10E according to the fifth embodiment where the gas barrier layer 5 comprises an inorganic compound layer and a coating layer. The protective layer 6, base layer 1, printing 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 10G can be those described in the fifth embodiment.

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

[0222] Furthermore, the laminate 10G 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, and in particular, better heat sealability. Accordingly, by adopting the above configuration for the laminate 10G, the temperature range for heat sealing performed for bag making is expanded, and a decrease in productivity becomes even less likely.

[0223] Furthermore, the laminate 10G includes an intermediate layer 8 whose degree of crystallinity is within the above range. This intermediate layer 8 enhances the strength of the laminate 10G, particularly its puncture strength. Therefore, the laminate 10G has excellent strength, especially puncture strength.

[0224] Furthermore, the laminate 10G contains polyethylene in the base layer 1, the intermediate layer 8, and the sealant layer 2, with the polyethylene content being 90% by mass or more. This laminate has excellent recyclability.

[0225] Furthermore, laminates with a high polyethylene content are less rigid compared to other laminates, and therefore are more likely to be bent when used as packaging material. Increased bending increases the likelihood of pinhole formation, but laminate 10G, which has excellent puncture strength, is less prone to developing pinholes.

[0226] Furthermore, in the laminate 10G, since the base layer 1 and the intermediate layer 8 are transparent, for example, regardless of whether the printed layer 4 is located between the base layer 1 and the sealant layer 2, the pattern displayed by the printed layer 4 is clearly visible when observed from the protective layer 6 side. In addition, the contents of a packaged article containing the laminate 10G described above are highly visible.

[0227] <8> Eighth Embodiment <8.1> Laminate Figure 9 is a schematic cross-sectional view showing a laminate according to the eighth embodiment of the present invention. The laminate 10H shown in Figure 9 comprises a protective layer 6, a base layer 1, a printing 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 polyethylene content of the laminate 10H is 90% by mass or more. The laminate 10H is the same as the case in the laminate 10F according to the sixth embodiment where the gas barrier layer 5 comprises an inorganic compound layer and a coating layer. The protective layer 6, base layer 1, printing 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 The laminate 10H has a degree of crystallinity of the base layer 1 within the above range. Therefore, like laminate 10A1, laminate 10H has excellent heat resistance.

[0229] Furthermore, the laminate 10H 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, and in particular, better heat sealability. Accordingly, by adopting the above configuration for the laminate 10H, the temperature range for heat sealing performed for bag making is expanded, and a decrease in productivity becomes even less likely.

[0230] Furthermore, the laminate 10H includes an intermediate layer 8 whose degree of crystallinity is within the above range. This intermediate layer 8 enhances the strength of the laminate 10H, particularly its drop strength. That is, in the laminate 10H, when used in packaging, the intermediate layer 8 located inside 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, packaged items using the laminate 10H as a packaging material are less likely to be damaged (broken) by drops. Consequently, the laminate 10H has excellent strength, particularly drop strength.

[0231] Furthermore, laminate 10H has a polyethylene content of 90% or more by mass. Therefore, laminate 10H also has excellent recyclability.

[0232] The printing layer 4 may be provided on the surface of the substrate 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 viewed with good visibility. Note that the printing layer 4 may be omitted.

[0233] <9> Ninth Embodiment Figure 10 is a schematic diagram showing a packaged article according to the ninth embodiment of the present invention.

[0234] The packaged article 100A shown in Figure 10 includes a packaging body 110A and the contents contained therein.

[0235] The packaging 110A is a flat pouch. The packaging 110A includes a pair of main films. Each of the main films is either one of the laminates described in the first to eighth embodiments, or cut from one of them. The main films are overlapped so that their sealant layers face each other, and their periphery is heat-sealed to one another. The packaging 110A is provided with a notch in its heat-sealed portion as an easy-open structure.

[0236] The contents may be liquids, solids, or mixtures thereof. Examples of contents include food or pharmaceuticals.

[0237] <10> Tenth Embodiment Figure 11 is a schematic diagram showing a packaged article according to the 10th embodiment of the present invention.

[0238] The packaged article 100B shown in Figure 11 includes a packaging body 110B and contents contained therein. The contents are, for example, the same as those described for packaged article 100A.

[0239] The packaging 110B is a standing pouch. The packaging 110B includes a pair of body films and a bottom film. Each of these films is either one of the laminates described in the first to eighth embodiments, or cut from one of them.

[0240] The pair of main films are overlapped so that their sealant layers face each other, and their periphery is heat-sealed to each other except for one end and the area near it. The bottom film is folded in half so that it forms a mountain fold when viewed from the sealant layer side, and at the position of the one end, it is sandwiched between the pair of main films so that the mountain fold faces the other end of the main films. The bottom film is heat-sealed to the pair of main films except for its central part. In addition, the outer surfaces of the bottom film are bonded together at the bottom sides of the packaging 110B.

[0241] The packaging body 110B has a notch provided as an easy-opening structure at a portion where the main body films are heat-sealed to each other. The easy-opening structure may be provided such that when the packaged article 100B is opened, the upper corner portion thereof can be used as a mouth portion. Alternatively, the packaged article 100B may further include a mouth member and a lid body described in the eleventh embodiment.

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

[0243] The packaged article 100C shown in FIG. 12 includes a packaging body 110C and the contents accommodated therein. The contents are, for example, the same as those described for the packaged article 100A.

[0244] The packaging body 110C is a gusseted pouch. The packaging body 110C includes a container body 110C1, a mouth member 110C2, and a lid body 110C3.

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

[0246] The pair of main body films are overlapped such that their sealant layers face each other and sandwich a part of the mouth member 110C2 at one end. The peripheral edges of these main body films are heat-sealed to the mouth member 110C2 at the above-mentioned one end and are also heat-sealed to each other in the vicinity thereof. Further, the peripheral edges of these main body films are heat-sealed to each other at the opposite ends except for the regions on both sides.

[0247] Each of the side films is folded in half so that it forms a mountain fold when viewed from the sealant layer side. These side films are sandwiched between the pair of main films on both sides, with the mountain folds facing each other. A portion of the peripheral edge of each side film is heat-sealed to one side of the main film, and the remaining portion of the peripheral edge is heat-sealed to the other side of the main film. In addition, the outer surfaces of each side film are bonded together at the upper and lower positions of the packaging 110C, respectively. The container body 110C1 may also include a bottom film.

[0248] As described above, the mouth member 110C2 is sandwiched between the main body film and includes a heat-sealed portion. 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 male threads on the outer surface of its side wall. The lid 110C3 has a bottomed cylindrical shape. The lid 110C3 is provided with female threads on the inner surface of its side wall and is screwed into the mouth portion of the mouth member 110C2. [Examples]

[0249] The results of tests conducted in connection with the present invention are described below. (1) Exam A (1.1) Manufacturing of laminates (1.1.1) Example 1A The laminate 10A2 shown in Figure 2 was manufactured by the following method. First, a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% was prepared as the base layer. The crystallinity shown in this example, as well as in the examples and comparative examples described below, was measured using the measurement method described above.

[0250] Next, on one side of the substrate layer, silicon dioxide (SiO₂) is added as an inorganic compound layer. x A vapor-deposited film was formed. Subsequently, a printed layer was formed on the inorganic compound layer.

[0251] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the printed surface of the substrate layer. Then, a sealant layer, a linear low-density polyethylene resin (LLDPE) film (60 μm thick), was laminated to the substrate layer via this adhesive layer. The laminate was created in the manner described above.

[0252] (1.1.2) Example 2A The laminate 10A2 shown in Figure 2 was manufactured using the same method as in Example 1A, except that an inorganic compound layer was not provided.

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

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

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

[0256] (1.1.6) Example 6A Laminate 10A2, shown in Figure 2, was manufactured in the same manner as in Example 1A, except that a polyethylene film with a thickness of 20 μm and a crystallinity of 54.1% was used as the base layer, instead of a polyethylene film with 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 manufactured in the same manner as in Example 1A, except that a polyethylene film with a thickness of 30 μm and a crystallinity of 55.9% was used instead of a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% as the base material layer.

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

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

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

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

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

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

[0264] (1.2) Measurement and evaluation methods The substrate layer used in the manufacture of the above-mentioned laminate was subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction pattern obtained from these measurements was then examined to determine whether it had sharp diffraction peaks corresponding to the (110) plane.

[0265] Furthermore, the sealing properties, heat resistance, visibility, and gas barrier properties of the above-mentioned laminate were evaluated. The evaluation methods for sealing properties, heat resistance, visibility, and gas barrier properties are described below.

[0266] (1.2.1) Method for evaluating sealing performance Samples cut from the laminate into 10 cm squares were folded in half with the sealant layer facing inward and heat-sealed using a heat seal tester. Specifically, the bottom sealing temperature was first set to 100°C and the top sealing temperature to 120°C, and a pressure of 0.1 MPa was applied for 1 second. Then, the presence or absence of melting of the sealing surface was checked, and the area on the top surface of the folded sample where the heat seal bar was applied was observed. If neither the sealing surface nor the top surface of the sample melted, the top sealing temperature was increased by 10°C increments while keeping the bottom sealing temperature at 100°C, and the same pressurization and observation were performed until at least one of the sealing surface and the top surface of the sample melted. The sealing performance 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 in terms of appearance. B: The top surface of the sample was melted, which presented a visual problem.

[0267] (1.2.2) Method for evaluating heat resistance A sample made by cutting the laminate into a 10 cm square was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was set to 30°C and the top sealing temperature to 170°C, and a pressure of 0.2 MPa was applied to the folded sample for 1 second. Then, the presence or absence of melting of the sealed surface was checked, and the area of ​​the top surface of the folded sample to which the heat seal bar was applied was observed to see if it was adhering to the heat seal bar, and the heat resistance was evaluated according to the following criteria. A: The top surface of the sample did not adhere to the heat sealing bar. B: The top surface of the sample adhered to the heat sealing bar.

[0268] (1.2.3) Method for evaluating visibility The pattern displayed by the printed layer was visually observed from the substrate layer side, and its visibility was evaluated according to the following criteria. A: We were able to clearly see the pattern displayed by the printed layer. B: The pattern displayed by the printed layer was blurry and unclear.

[0269] (1.2.4) Method for evaluating gas barrier properties The laminate was boiled, and then the oxygen transmission rate (OTR) was measured at 30°C and 70% relative humidity. This measurement was performed in accordance with JIS K-7126, Method B. The gas barrier properties were then evaluated based on the oxygen transmission rate according to the following criteria. A: OTR is 10cc / m 2 It was less than ・day·atm. B:OTR is 10cc / m 2 It was more than 1 day ATM.

[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, laminates with a base layer crystallinity of 35% or higher all exhibited good sealing properties, heat resistance, and visibility. In contrast, laminates with a base layer crystallinity of less than 35% all exhibited insufficient sealing properties, heat resistance, and visibility.

[0274] (2) Test B (2.1) Manufacturing of laminates (2.1.1) Example 1B The laminate 10B shown in Figure 3 was manufactured 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 the gas barrier layer 5 consisted of an inorganic compound layer and a coating layer.

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

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

[0277] (Preparation of coating solution for forming protective and protective layers) A coating solution for forming a protective layer and a coating layer containing an organic-inorganic mixture (hereinafter also simply referred to as "coating solution") was prepared by mixing the following solutions 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 72.1g of 0.1N hydrochloric acid to 17.9g of tetraethoxysilane (Si(OC2H5)4) and 10g of methanol, and stirring for 30 minutes. Solution B: 5% by mass of polyvinyl alcohol in water / methanol solution (water:methanol mass ratio is 95:5). Solution C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate with a mixture of water and isopropyl alcohol (water:isopropyl alcohol mass ratio is 1:1) to a solid content of 5% by 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 / cm³. 3 A polyethylene film was prepared. The degree of crystallinity shown in this example and in the examples and comparative examples described below was measured using the measurement method described above.

[0279] Next, one side of the substrate layer was subjected to corona treatment. Subsequently, the coating solution prepared above was applied to the corona-treated side of the substrate layer by gravure coating and dried to form a protective layer consisting of an organic-inorganic mixture with a thickness of 0.5 μm (dry state).

[0280] Next, the other side of the substrate layer was subjected to corona treatment. Subsequently, the aforementioned anchor coating agent was applied to the corona-treated side of the substrate layer by gravure coating to form an anchor coating layer with a thickness of 0.1 μm (dry state).

[0281] Next, using an electron beam heating vacuum deposition apparatus, silicon dioxide (SiO₂) is used as the inorganic compound layer. xA vapor-deposited film was formed to a thickness of 40 nm. Subsequently, the coating solution prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm (dry state).

[0282] Subsequently, a water-based flexographic ink was pattern-printed onto the coating layer to form a printed layer.

[0283] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the printed surface of the substrate layer. Then, a sealant layer, a linear low-density polyethylene resin (LLDPE) film (60 μm thick), was laminated to the substrate layer via this adhesive layer. The laminate was created in the manner described above.

[0284] (2.1.2) Example 2B In the laminate 10B shown in Figure 3, instead of using the polyethylene fill shown above with a crystallinity of 58.5% as the base layer, a material with a thickness of 25 μm, a crystallinity of 55.9%, a haze of 5.9%, and a density of 0.95 g / cm³ is used. 3 The polyethylene film used was manufactured in the same manner as in Example 1B, except that a polyethylene film was used. This polyethylene film is a biaxially oriented film and has been corona-treated on one side.

[0285] (2.1.3) Example 3B The laminate 10B shown in Figure 3 was manufactured using the same method as in Example 2B, except that a protective layer was not provided.

[0286] (2.1.4) Example 4B The laminate 10B shown in Figure 3 was manufactured in the same manner as in Example 1B, except that instead of forming a protective layer with a thickness of 0.5 μm by coating it with polyamide-imide resin, a protective layer with a thickness of 0.5 μm made of urethane resin was formed.

[0287] (2.1.5) Example 5B The laminate 10B shown in Figure 3 was manufactured in the same manner as in Example 1B, except that instead of forming a 0.5 μm thick protective layer by coating it with polyamide-imide resin, a 1 μm thick protective layer made of urethane resin was formed.

[0288] (2.1.6) Example 6B Laminate 10B, shown in Figure 3, was manufactured in the same manner as in Example 1B, except that instead of forming a 0.5 μm thick protective layer by coating it with polyamide-imide resin, a 1 μm thick protective layer made of ethylene-vinyl alcohol copolymer (EVOH) was formed.

[0289] (2.1.7) Example 7B The laminate 10B shown in Figure 3 was manufactured in the same manner as in Example 1B, except that instead of forming a 0.5 μm thick protective layer by coating it with polyamide-imide resin, a 1 μm thick protective layer made of acrylic resin was formed.

[0290] (2.1.8) Comparative example 1B Laminate 10B shown in Figure 3 was manufactured in the same manner as in Example 1B, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film shown above with a crystallinity of 58.5% as the base layer, a substrate with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm³ was used. 3 A polyethylene film was used. This polyethylene film was corona-treated on one side.

[0291] (2.2) Measurement and evaluation methods The substrate layer used in the manufacture of the above-mentioned laminate was subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction pattern obtained from these measurements was then examined to determine whether it had sharp diffraction peaks corresponding to the (110) plane.

[0292] Furthermore, the sealability, heat resistance, visibility, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealability, heat resistance, visibility, and recyclability are described below.

[0293] (2.2.1) Method for evaluating sealing performance Samples, each consisting of a 10 cm square of laminate, were 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 sealing performance was evaluated according to the following criteria. A: There was no melting on the sample surface, and there were no problems with its appearance. B: The surface of the sample was melted, which presented a visual problem.

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

[0295] (2.2.3) Method for evaluating visibility Visibility was evaluated using the method described in (1.2.3).

[0296] (2.2.4) Method for evaluating recyclability The proportion of polyethylene in the total mass of the laminate was calculated. This proportion was then used to evaluate its recyclability, referring to the following criteria. Here, a rating of A indicates excellent recyclability as a monomaterial. 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, laminates with a base layer crystallinity of 35% or higher all exhibited good recyclability, heat resistance, and visibility. Furthermore, laminates with a base layer crystallinity of 35% or higher and a protective layer also showed excellent sealing properties. In contrast, laminates with a base layer crystallinity of less than 35% and without a protective layer had insufficient sealing properties, heat resistance, and visibility.

[0300] (3) Test C (3.1) Manufacturing of laminates (3.1.1) Example 1C The laminate 10C shown in Figure 4 was manufactured by the following method. In this example, an anchor coat layer was further provided between the base layer 1 and the inorganic compound layer 5.

[0301] First, the anchor coating agent and the coating solution for forming the protective layer were prepared in the same manner as in Example 1B. In addition, an organic solvent solution of polyamide-imide resin (non-volatile component concentration 5% by mass) was prepared as the coating solution for forming the 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 / cm³. 3 A polyethylene film was prepared. This polyethylene film was subjected to corona treatment on both sides. The degree of crystallinity shown in this example, as well as in the examples and comparative examples described below, was measured using the measurement method described above.

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

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

[0305] Next, using an electron beam heating vacuum deposition apparatus, silicon dioxide (SiO₂) is used as the inorganic compound layer. x A vapor-deposited film was formed to a thickness of 40 nm. Subsequently, the coating solution prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm (dry state).

[0306] Subsequently, a printed layer was formed on the coating layer by flexographic printing using water-based flexographic ink to create an image.

[0307] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the printed surface of the substrate layer. Then, a sealant layer, a linear low-density polyethylene resin (LLDPE) film (60 μm thick), was laminated to the substrate layer via this adhesive layer. The laminate was created in the manner described above.

[0308] (3.1.2) Example 2C The laminate 10C shown in Figure 4 was manufactured using the same method as in Example 1C, except that the thickness of the protective layer was changed from 0.5 μm to 1 μm, and a coating layer was omitted.

[0309] (3.1.3) Example 3C The laminate 10C shown in Figure 4 was manufactured using the same method 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 The laminate 10C shown in Figure 4 was manufactured using the same method as in Example 1C, except that a protective layer was not provided.

[0311] (3.1.5) Comparative example 1C Laminate 10C shown in Figure 4 was manufactured in the same manner as in Example 1C, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5% 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.

[0312] (3.2) Measurement and evaluation methods The substrate layer used in the manufacture of the above-mentioned laminate was subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction pattern obtained from these measurements was then examined to determine whether it had sharp diffraction peaks corresponding to the (110) plane.

[0313] Furthermore, the sealability, heat resistance, visibility, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealability, heat resistance, visibility, and recyclability are described below.

[0314] (3.2.1) Method for evaluating sealing performance The sealing performance was evaluated using the method described in (1.2.1).

[0315] (3.2.2) Method for evaluating heat resistance Heat resistance was evaluated using the method described in (2.2.2).

[0316] (3.2.3) Method for evaluating visibility Visibility was evaluated using the method described in (1.2.3).

[0317] (3.2.3) Method for evaluating recyclability 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, laminates with a base layer crystallinity of 35% or higher all exhibited good recyclability, heat resistance, and visibility. Furthermore, laminates with a base layer crystallinity of 35% or higher and a protective layer also exhibited excellent sealing properties. In contrast, laminates with a base layer crystallinity of less than 35% and without a protective layer had insufficient sealing properties, heat resistance, and visibility.

[0321] (4) Test D (4.1) Manufacturing of laminates (4.1.1) Example 1D The laminate 10D shown in Figure 5 was manufactured by the following method. First, the base layer and 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. 3 A polyethylene film was prepared. The degree of crystallinity shown in this example and in the examples and comparative examples described below was measured using the measurement method described above.

[0322] Next, on the intermediate layer, silicon dioxide (SiO₂) is added as an inorganic compound layer. x A vapor-deposited film was formed to a thickness of 50 nm.

[0323] A dry laminating adhesive (urethane-based adhesive) was applied to the base material layer to form a first adhesive layer. The base material layer and the intermediate layer were bonded together with the first adhesive layer in between, so that the base material layer and the inorganic compound layer faced each other. Next, a printing layer was formed on the back surface of the intermediate layer where 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 laminating adhesive (urethane-based adhesive) was applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer were then bonded together with the second adhesive layer in between, so that the sealant layer and the printed layer faced each other. The laminate was created in the manner described above. (4.1.2) Example 2D The laminate 10D shown in Figure 5 was manufactured in the same manner as in Example 1D, except that a gas barrier polyamine-based adhesive was used instead of a urethane-based adhesive for the first and second adhesive layers.

[0325] (4.1.3) Example 3D In the laminate 10D shown in Figure 5, instead of using the polyethylene film with a crystallinity of 58.5% as the base layer, a material with a thickness of 25 μm, a crystallinity of 71.8%, a haze of 4.1%, and a density of 0.95 g / cm³ is used. 3 The polyethylene film used was manufactured in the same manner as in Example 1D, except that a polyethylene film was used. This polyethylene film is a longitudinally uniaxially oriented film and has been corona-treated on one side.

[0326] (4.1.4) Example 4D Laminate 10D shown in Figure 5 was manufactured in the same manner as in Example 1D, except as follows: Instead of using the polyethylene film shown above with a crystallinity of 58.5% as the base layer, a substrate layer 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 A polyethylene film was used. This polyethylene film is a biaxially oriented film and has been corona-treated on one side. Furthermore, instead of using the above polyethylene film with a crystallinity of 58.5% as an intermediate layer, a film with a thickness of 25 μm, a crystallinity of 71.8%, a haze of 4.1, and a density of 0.95 g / cm³ was used. 3A high-density polyethylene film was used. This polyethylene film is a longitudinally uniaxially oriented film and has been corona-treated on one side.

[0327] (4.1.5) Example 5D Instead of using the polyethylene film shown above with a crystallinity of 58.5% as the intermediate layer in the laminate 10D shown in Figure 5, a laminate with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm³ is used. 3 The polyethylene film used was manufactured in the same manner as in Example 1D, except that it was a polyethylene film. This polyethylene film was corona-treated on one side.

[0328] (4.1.6) Example 6D The laminate 10D shown in Figure 5 was manufactured using the same method as in Example 1D, except that a gas barrier layer was not provided.

[0329] (4.1.7) Comparative Example 1D In the laminate 10D shown in Figure 5, instead of using the polyethylene film with a crystallinity of 58.5% as the base layer, a laminate with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm³ is used. 3 The polyethylene film used was manufactured in the same manner as in Example 1D, except that it was a polyethylene film. This polyethylene film was corona-treated on one side.

[0330] (4.1.8) Comparative example 2D Instead of using the polyethylene film shown above with a crystallinity of 58.5% as the base layer and intermediate layer of the laminate 10D shown in Figure 5, a laminate with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm³ is used. 3 The polyethylene film used was manufactured in the same manner as in Example 1D, except that it was a polyethylene film. This polyethylene film was corona-treated on one side.

[0331] (4.1.9) Comparative example 3D Laminate 10D shown in Figure 5 was manufactured in the same manner as in Example 1D, except as follows: instead of using the polyethylene film shown above with a crystallinity of 58.5% as the base layer, a substrate with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm³ was used. 3 A polyethylene film was used. This polyethylene film was corona-treated on one side. Furthermore, no gas barrier layer was provided.

[0332] (4.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0333] Furthermore, the sealing properties, heat resistance, visibility, puncture strength, and gas barrier properties of the above-mentioned laminate were evaluated. The evaluation methods for sealing properties, heat resistance, visibility, puncture strength, and gas barrier properties are described below.

[0334] (4.2.1) Method for evaluating sealing performance The sealing performance was evaluated using the method described in (2.2.1).

[0335] (4.2.2) Method for evaluating heat resistance Heat resistance was evaluated using the method described in (1.2.2).

[0336] (4.2.3) Method for evaluating visibility Visibility was evaluated using the method described in (1.2.3).

[0337] (4.2.4) Method for evaluating 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 mean of the maximum forces was obtained as the penetration strength.

[0338] (4.2.5) Method for evaluating gas barrier properties The gas barrier properties were evaluated using the method described 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, laminates with a base layer crystallinity of 35% or higher all exhibited good sealing and heat resistance. Furthermore, laminates with a base layer and intermediate layer crystallinity of 35% or higher also showed excellent visibility and puncture strength. In contrast, laminates with a base layer crystallinity of less than 35% had insufficient sealing, heat resistance, and visibility.

[0343] (5) Exam E (5.1) Manufacturing of laminates (5.1.1) Example 1E The laminate 10E shown in Figure 6 was manufactured 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 the gas barrier layer 5 consisted of an inorganic compound layer and a coating layer.

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

[0345] The base layer and 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 / cm³.3 A polyethylene film was prepared. The degree of crystallinity shown in this example and in the examples and comparative examples described below was measured using the measurement method described above.

[0346] Next, one side of the substrate layer was subjected to corona treatment. Subsequently, the protective layer-forming coating solution prepared above was applied to the corona-treated side of the substrate layer by gravure coating and dried to form a protective layer consisting of an organic-inorganic mixture with a thickness of 0.5 μm.

[0347] Next, the other side of the substrate layer was subjected to corona treatment. Then, a pattern was printed with water-based flexographic ink onto the corona-treated side of the substrate layer to form a printed layer.

[0348] Corona treatment was applied to one side of the intermediate layer. Subsequently, the aforementioned anchor coating agent was applied to the corona-treated side of the intermediate layer by gravure coating to form an anchor coating layer with a thickness of 0.1 μm (dry state).

[0349] Next, using an electron beam heating vacuum deposition apparatus, silicon dioxide (SiO₂) is used as the inorganic compound layer. x A vapor-deposited film was formed on the anchor coat layer to a thickness of 40 nm. Subsequently, the coating solution prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm (dry state).

[0350] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the side opposite to the side where the inorganic compound layer of the intermediate layer was formed to form the first adhesive layer. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between, 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 laminating adhesive (urethane-based adhesive) was applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer were bonded together with the second adhesive layer in between, so that the sealant layer and the coating layer faced each other. The laminate was created in the manner described above.

[0352] (5.1.2) Example 2E Laminate 10E shown in Figure 6 was manufactured in the same manner as in Example 1E, except as follows: Instead of using the polyethylene film shown above with a crystallinity of 58.5% as the base layer and intermediate layer, a film 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 A polyethylene film was used. This polyethylene film has been corona-treated on one side.

[0353] (5.1.3) Example 3E Laminate 10E shown in Figure 6 was manufactured in the same manner as in Example 2E, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film shown above with a crystallinity of 55.9% as the intermediate layer, a film with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm³ was used. 3 A polyethylene film was used. This polyethylene film has been corona-treated on one side.

[0354] (5.1.4) Comparative Example 1E Laminate 10E shown in Figure 6 was manufactured in the same manner as in Example 1E, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5% as the base layer and intermediate layer, a film with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm³ was used. 3 A polyethylene film was used. This polyethylene film has been corona-treated on one side.

[0355] (5.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0356] Furthermore, the sealability, heat resistance, visibility, puncture strength, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealability, heat resistance, visibility, puncture strength, and recyclability are described below.

[0357] (5.2.1) Method for evaluating sealing performance The sealing properties (heat resistance) were evaluated using the method described in (2.2.1).

[0358] (5.2.2) Method for evaluating heat resistance Heat resistance was evaluated using the method described in (2.2.2).

[0359] (5.2.3) Method for evaluating visibility Visibility was evaluated using the method described in (1.2.3).

[0360] (5.2.4) Method for evaluating puncture strength Puncture strength was evaluated using the method described in (4.2.4).

[0361] (5.2.5) Method for evaluating recyclability 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, laminates with a base layer crystallinity of 35% or higher all exhibited good heat resistance, visibility, and puncture strength. Furthermore, laminates with a base layer and intermediate layer crystallinity of 35% or higher, and equipped with a protective layer, also showed excellent sealing properties and further improved puncture strength. In contrast, laminates with a base layer crystallinity of less than 35% and without a protective layer exhibited insufficient sealing properties, heat resistance, visibility, and puncture strength.

[0365] (6) Test F (6.1) Manufacturing of laminates (6.1.1) Example 1F The laminate 10F shown in Figure 7 was manufactured 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 the gas barrier layer 5 consisted of an inorganic compound layer and a coating layer.

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

[0367] The substrate layer has a thickness of 25 μm, a crystallinity of 58.5%, and a density of 0.950 g / cm³. 3 A polyethylene film was prepared. This polyethylene film was corona-treated on one side. The degree of crystallinity shown in this example, as well as in the examples and comparative examples described below, was measured using the measurement method described above.

[0368] Next, one side of the substrate layer was subjected to corona treatment. Subsequently, the protective layer-forming coating solution prepared above was applied to the corona-treated side of the substrate layer by gravure coating and dried to form a protective layer consisting of an organic-inorganic mixture with a thickness of 0.5 μm.

[0369] Next, the other side of the substrate layer was subjected to corona treatment. Then, a pattern was printed with water-based flexographic ink onto the corona-treated side of the substrate layer to form a printed layer.

[0370] Next, the intermediate layer has a thickness of 25 μm, a crystallinity of 27.5%, and a density of 0.950 g / cm³. 3 A polyethylene film was prepared. This polyethylene film has been corona-treated on one side.

[0371] The aforementioned anchor coating agent was applied using the gravure coating method to form an anchor coating layer with a thickness of 0.1 μm (dry state).

[0372] Next, as an inorganic compound layer, silicon dioxide (SiO₂) x A vapor-deposited film was formed on the anchor coat layer to a thickness of 40 nm. Subsequently, the coating solution prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm (dry state).

[0373] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the surface opposite to the surface where the inorganic compound layer of the intermediate layer was formed to form the first adhesive layer. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between, 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 laminating adhesive (urethane-based adhesive) was applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer were bonded together with the second adhesive layer in between, so that the sealant layer and the coating layer faced each other. The laminate was created in the manner described above.

[0375] (6.1.2) Example 2F Laminate 10F shown in Figure 7 was manufactured in the same manner as in Example 1F, except as follows: Instead of using the polyethylene film shown above with a crystallinity of 58.5% as the base layer, a substrate with a thickness of 25 μm, a crystallinity of 55.9%, a haze of 21.5%, and a density of 0.95 g / cm³ was used. 3A polyethylene film was used. This polyethylene film has been corona-treated on one side.

[0376] (6.1.3) Example 3F Laminate 10F shown in Figure 7 was manufactured in the same manner as in Example 1F, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film shown above with a crystallinity of 58.5% as the base layer and the polyethylene film shown above with a crystallinity of 27.5% as the intermediate layer, films with a thickness of 25 μm, a crystallinity of 55.9%, and a density of 0.95 g / cm³ were used. 3 A polyethylene film was used. This polyethylene film has been corona-treated on one side.

[0377] (6.1.4) Comparative Example 1F Laminate 10F shown in Figure 7 was manufactured in the same manner as in Example 1F, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5% as the base layer, a film with a thickness of 25 μm, a crystallinity of 27.5%, and a density of 0.950 g / cm³ was used. 3 A polyethylene film was used. This polyethylene film is corona-treated on one side. Furthermore, instead of using the above polyethylene film with a crystallinity of 27.5% as an intermediate layer, a film with a thickness of 25 μm, a crystallinity of 55.9%, and a density of 0.95 g / cm³ was used. 3 A polyethylene film was used. This polyethylene film has been corona-treated on one side.

[0378] (6.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0379] Furthermore, the sealing properties, heat resistance, drop strength, and recyclability of the above-mentioned laminate were evaluated. The evaluation methods for sealing properties, heat resistance, drop strength, and recyclability are described below.

[0380] (6.2.1) Method for evaluating sealing performance The sealing performance was evaluated using the method described in (2.2.1).

[0381] (6.2.2) Method for evaluating heat resistance Heat resistance was evaluated using the method described in (2.2.2).

[0382] (6.2.3) Method for evaluating drop strength Ten bags were made by cutting the laminate to a predetermined size and heat-sealing the edges. Each bag had an opening for inserting contents. The dimensions of the bags 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 packaged items. Then, each packaged item 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 items whose bags broke within 50 drops to the total number of packaged items (10) was calculated as the drop strength.

[0383] (6.2.4) Method for evaluating recyclability 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, laminates with a base layer crystallinity of 35% or higher all exhibited good heat resistance while maintaining recyclability. Furthermore, laminates with a base layer crystallinity of 35% or higher, an intermediate layer crystallinity of less than 35%, and a protective layer also exhibited excellent sealing properties and drop strength. In contrast, laminates with a base layer crystallinity of less than 35% and no protective layer had insufficient sealing properties, heat resistance, and drop strength.

[0387] (7) Test G (7.1) Manufacturing of laminates (7.1.1) Example 1G The laminate 10G shown in Figure 8 was manufactured 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, the coating solution for forming the anchor coat layer and the coating solution for forming the protective layer were prepared in the same manner as in Example 1B. Furthermore, an organic solvent solution of polyamide-imide resin (non-volatile component concentration 5% by mass) was prepared as a coating liquid for forming a protective layer.

[0389] The base layer and 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 / cm³. 3 A polyethylene film was prepared. This polyethylene film has a three-layer structure (HDPE / MDPE / HDPE) and is corona-treated on both sides. The degree of crystallinity shown in this example and the examples and comparative examples described below was measured using the measurement method described above.

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

[0391] Next, the aforementioned anchor coating agent was applied to one side of the intermediate layer that had undergone corona treatment by gravure coating to form an anchor coating layer with a thickness of 0.1 μm (dry state).

[0392] Next, as an inorganic compound layer, transparent silicon dioxide (SiO₂) is deposited using an electron beam heating vacuum deposition apparatus. x A vapor-deposited film was formed on the anchor coat layer to a thickness of 40 nm. 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] Next, the coating solution prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm (dry state).

[0394] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the side opposite to the side where the inorganic compound layer of the intermediate layer was formed to form the first adhesive layer. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between, 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 laminating adhesive (urethane-based adhesive) was applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer were bonded together with the second adhesive layer in between, so that the sealant layer and the coating layer faced each other. The laminate was created in the manner described above.

[0396] (7.1.2) Example 2G The laminate 10G shown in Figure 8 was manufactured using the same method 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 The laminate 10G shown in Figure 8 was manufactured using the same method 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 manufactured in the same manner as in Example 1G, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5% as 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 manufactured in the same manner as in Example 1G, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5% as described above for the base layer and intermediate layer, a polyethylene film with a thickness of 25 μm and a crystallinity of 27.6% was used.

[0397] (7.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0398] Furthermore, the sealability, heat resistance, visibility, puncture strength, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealability, heat resistance, visibility, puncture strength, and recyclability are described below.

[0399] (7.2.1) Method for evaluating sealing performance The sealing performance was evaluated using the method described in (1.2.1).

[0400] (7.2.2) Method for evaluating heat resistance Heat resistance was evaluated using the method described in (2.2.2).

[0401] (7.2.3) Method for evaluating visibility Visibility was evaluated using the method described in (1.2.3).

[0402] (7.2.4) Method for evaluating puncture strength Puncture strength was evaluated using the method described in (4.2.4).

[0403] (7.2.5) Method for evaluating recyclability 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, laminates with a base layer crystallinity of 35% or higher all exhibited good recyclability, heat resistance, and visibility. Furthermore, laminates with a base layer and intermediate layer crystallinity of 35% or higher and equipped with a protective layer also showed excellent sealing properties and puncture strength. In contrast, laminates with a base layer crystallinity of less than 35% and without 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 The laminate 10H shown in Figure 9 was manufactured 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, the coating solution for forming the anchor coat layer and the coating solution for forming the protective layer were prepared in the same manner as in Example 1B. Furthermore, an organic solvent solution of polyamide-imide resin (non-volatile component concentration 5% by mass) was prepared as a coating liquid for forming a protective layer.

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

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

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

[0411] Next, as an inorganic compound layer, transparent silicon dioxide (SiO₂) is deposited using an electron beam heating vacuum deposition apparatus. x A vapor-deposited film was formed on the anchor coat layer to a thickness of 40 nm. 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] Next, the coating solution prepared above was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm (dry state).

[0413] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the side opposite to the side where the inorganic compound layer of the intermediate layer was formed to form the first adhesive layer. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between, 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 laminating adhesive (urethane-based adhesive) was applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer were bonded together with the second adhesive layer in between, so that the sealant layer and the coating layer faced each other. The laminate was created in the manner described above.

[0415] (8.1.2) Example 2H The laminate 10H shown in Figure 9 was manufactured using the same method as in Example 1H, except that the thickness of the protective layer was changed from 0.5 μm to 1 μm, and a coating layer was omitted.

[0416] (8.1.3) Example 3H The laminate 10H shown in Figure 9 was manufactured using the same method 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 Figure 9, was manufactured in the same manner as in Example 1H, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film with a crystallinity of 27.6% mentioned 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 corona-treated on both sides.

[0418] (8.1.5) Comparative Example 1H Laminate 10H shown in Figure 9 was manufactured in the same manner as in Example 1H, except that a protective layer was not provided. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5% mentioned 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 corona-treated on both sides. Furthermore, instead of using the polyethylene film with a crystallinity of 27.6% mentioned 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 corona-treated on both sides.

[0419] (8.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0420] Furthermore, the sealability, heat resistance, visibility, drop strength, and recyclability of the above-mentioned laminate were evaluated. The evaluation methods for sealability, heat resistance, visibility, drop strength, and recyclability are described below.

[0421] (8.2.1) Method for evaluating sealing performance The sealing performance was evaluated using the method described in (1.2.1).

[0422] (8.2.2) Method for evaluating visibility Visibility was evaluated using the method described in (1.2.2).

[0423] (8.2.3) Method for evaluating drop strength The drop strength was evaluated using the method described in (6.2.3).

[0424] (8.2.4) Method for evaluating recyclability 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, laminates with a base layer crystallinity of 35% or higher all exhibited good recyclability, heat resistance, and visibility. Furthermore, laminates with a base layer crystallinity of 35% or higher, an intermediate layer crystallinity of less than 35%, and a protective layer also showed excellent sealing and drop strength. In contrast, laminates with a base layer crystallinity of less than 35% and no protective layer exhibited insufficient sealing, heat resistance, and visibility. [Explanation of Symbols]

[0427] 1...Base layer, 2...Sealant layer, 3...Adhesive layer, 3A...First adhesive layer, 3B...Second adhesive layer, 4...Printing 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...Packaging body, 110B...Packaging body, 110C...Packaging body, 110C1...Container body, 110C2...Opening member, 110C3...Lid. The invention described in the original claims of this application is listed below. [1] The substrate layer, adhesive layer, and sealant layer are provided in this order. The base layer and the sealant layer contain polyethylene. The substrate layer is a laminate in which the degree of crystallinity, which is the ratio of the crystal peak area to the total peak area, is 40% or more, as measured by the parallel beam method of X-ray diffraction in the range of diffraction angles from 10° to 30°. However, the laminate comprises a substrate, an image forming layer, an adhesive layer, a vapor deposition layer, an intermediate layer, an adhesive layer, and a heat seal layer in this order, Each of the above-mentioned substrate and the above-mentioned intermediate layer has a density of 0.961 g / cm³. 3 A high-density polyethylene layer composed of high-density polyethylene, with a density of 0.941 g / cm³. 3 A medium-density polyethylene layer composed of medium-density polyethylene, with a density of 0.961 g / cm³. 3 A three-layer co-pressed stretched film is formed by laminating a high-density polyethylene layer composed of high-density polyethylene in this order, excluding laminates in which the heat-seal layer is an unstretched polyethylene film. [2] The laminate according to Appendix [1], further comprising an intermediate layer containing polyethylene interposed between the base material layer and the sealant layer. [3] The intermediate layer is a laminate as described in Appendix [2], wherein the degree of crystallinity, which is the ratio of the crystal peak area to the total peak area, measured by the parallel beam method of X-ray diffraction in the range of diffraction angles of 10° to 30°, is 35% or more. [4] The laminate described in Appendix [2], wherein the intermediate layer is an unstretched film with a crystallinity of less than 35%, which is the ratio of the crystal peak area to the total peak area, as measured by the parallel beam method of X-ray diffraction in the range of diffraction angles of 10° to 30°. [5] The laminate as described in Appendix [1] further comprises a protective layer as the outermost layer facing the sealant layer with the base layer in between, wherein the protective layer contains a thermosetting resin. [6] The laminate according to Appendix [1] further comprising a gas barrier layer interposed between the substrate layer and the sealant layer, wherein the gas barrier layer includes an inorganic compound layer. [7] The substrate layer is a laminate as described in Appendix [1], wherein the degree of crystallinity is 50% or more. [8] The laminate described in Appendix [1], wherein the base material layer is a uniaxially oriented film. [9] The laminate according to Appendix [1], wherein the sealant layer is white.

[10] The laminate as described in Appendix [1], wherein the proportion of polyethylene in the laminate is 90% by mass or more.

[11] The laminate according to Appendix [2], wherein the adhesive layer comprises a first adhesive layer and a second adhesive layer, the first adhesive layer interposed between the substrate layer and the intermediate layer, and the second adhesive layer interposed between the intermediate layer and the sealant layer.

[12] A package containing a laminate as described in any of the footnotes [1] to

[11] .

[13] The packaging described in the appendix

[12] is a standing pouch.

[14] A packaged article including the packaging described in Appendix

[12] and the contents contained therein.

Claims

1. The substrate layer, adhesive layer, and sealant layer are provided in this order. The base layer and the sealant layer contain polyethylene. The substrate layer is a packaging material consisting of a laminate in which the degree of crystallinity, which is the ratio of the crystal peak area to the total peak area, is 55.9% or more, as measured by the parallel beam method of X-ray diffraction in the diffraction angle range of 10° to 30°. However, the laminate comprises a substrate, a printed layer, an adhesive layer, a vapor-deposited layer, an intermediate layer, an adhesive layer, and a sealant layer in this order, Each of the aforementioned substrate and intermediate layer has a density of 0.961 g / cm³. ３ A high-density polyethylene layer composed of high-density polyethylene, with a density of 0.941 g / cm³. ３ A medium-density polyethylene layer composed of medium-density polyethylene, with a density of 0.961 g / cm³. ３ A three-layer co-pressed stretched film is formed by laminating a high-density polyethylene layer composed of high-density polyethylene in this order, excluding laminates in which the sealant layer is an unstretched polyethylene film.

2. The packaging material according to claim 1, further comprising an intermediate layer containing polyethylene, interposed between the base material layer and the sealant layer.

3. The packaging material according to claim 2, wherein the intermediate layer has a crystallinity of 35% or more, which is the ratio of the crystal peak area to the total peak area, as measured by the parallel beam method of X-ray diffraction in the range of diffraction angles of 10° to 30°.

4. The packaging material according to claim 2, wherein the intermediate layer is an unstretched film with a crystallinity of less than 35%, which is the ratio of the crystal peak area to the total peak area, as measured by the parallel beam method of X-ray diffraction in the range of diffraction angles of 10° to 30°.

5. The packaging material according to claim 1, further comprising a protective layer as the outermost layer facing the sealant layer with the base layer in between, wherein the protective layer contains a thermosetting resin.

6. The packaging material according to claim 1, further comprising a gas barrier layer interposed between the base material layer and the sealant layer, wherein the gas barrier layer includes an inorganic compound layer.

7. The packaging material according to claim 1, wherein the base layer is a uniaxially oriented film.

8. The packaging material according to claim 1, wherein the sealant layer is white.

9. The packaging material according to claim 1, wherein the proportion of polyethylene in the laminate is 90% by mass or more.

10. The packaging material according to claim 2, wherein the adhesive layer comprises a first adhesive layer and a second adhesive layer, the first adhesive layer being interposed between the base material layer and the intermediate layer, and the second adhesive layer being interposed between the intermediate layer and the sealant layer.

11. A package containing the packaging material described in any one of claims 1 to 10.

12. The packaging according to claim 11, which is a standing pouch.

13. A packaged article comprising the packaging body described in claim 11 and the contents contained therein.

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