Laminate, package, and packaged article

Abstract

To provide a laminate mainly made of polyethylene that exhibits excellent heat resistance.SOLUTION: A laminate 10A1 includes a substrate layer 1, an adhesive agent layer 3, and a sealant layer 2 in this order. The substrate layer 1 and the sealant layer 2 each include polyethylene. The substrate layer 1 has a probe descendent temperature of 180°C or higher.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Packaging materials used for packages such as packaging bags are required to have various properties depending on the application. The properties required for packaging materials include, for example, the strength required for the package, suitability for bag making, suitability for printing, suitability for transportation, and preservability of the contents. In order to satisfy these requirements, it has been common to use packaging materials made by combining multiple types of synthetic resin films with different properties.

[0003] For example, Patent Document 1 describes a packaging material in which a resin film made of polyethylene is laminated with a resin film made of polyester, polyamide, or the like.

[0004] Patent Document 2 describes a multilayer film in which a gas barrier layer formed by applying a dispersion liquid containing an inorganic layered compound and a water-soluble polymer on at least one surface of a base layer made of a thermoplastic resin, an overcoat layer containing a cationic resin and a resin having a hydroxyl group, an adhesive layer, and a sealant layer are laminated in this order. This document describes a specific example in which a nylon film is used as the base layer and a linear low-density polyethylene film is used as the sealant layer.

[0005] In recent years, with the growing demand for the creation of a recycling-oriented society, there is a demand for packaging materials with high recyclability. However, as described above, conventional packaging materials are composed of different types of resin materials. It is difficult to separate these resin materials from each other.

[0006] Generally, packaging materials are considered to have high recyclability when the ratio of the main resin contained in the material is 90% by mass or more. As described above, most conventional packaging materials contain multiple types of resin materials and do not meet the above criteria.

[0007] As a result, most packaging materials are not currently recycled.

[0008] Patent Document 3 describes a laminate in which a stretched film made of polyethylene is used as a substrate, an adhesive layer and a heat seal layer made of polyethylene are provided thereon, and a deposition layer is provided at least one between the substrate and the adhesive layer and between the heat seal layer and the adhesive layer. This document describes that this laminate has sufficient strength, heat resistance, and barrier properties for use as a packaging material, and is also excellent in recyclability. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2009-202519 A [Patent Document 2] JP 2009-241359 A [Patent Document 3] JP 2020-055157 A Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a laminate which is mainly made of polyethylene and has excellent heat resistance.

[0011] According to one aspect of the present invention, there is provided a laminate comprising, in this order, a substrate layer, an adhesive layer, and a sealant layer, the substrate layer and the sealant layer containing polyethylene, and the substrate layer having a probe drop temperature of 180°C or higher.

[0012] According to another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the base layer has a probe drop temperature of 220° C. or less.

[0013] According to yet another aspect of the present invention, there is provided a laminate according to any of the above aspects, further comprising an intermediate layer interposed between the base layer and the sealant layer, the intermediate layer including polyethylene.

[0014] According to yet another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the intermediate layer has a probe drop temperature of 180° C. or less.

[0015] Alternatively, according to yet another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the intermediate layer has a probe drop temperature of 140°C or higher and lower than 180°C.

[0016] Alternatively, according to yet another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the intermediate layer has a probe drop temperature of 180° C. or higher.

[0017] According to yet another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the intermediate layer has a probe drop temperature of 220° C. or less.

[0018] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, further comprising a protective layer as an outermost layer facing the sealant layer with the base layer sandwiched therebetween.

[0019] According to yet another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the protective layer is made of a thermosetting resin.

[0020] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the base layer is a biaxially stretched film.

[0021] Alternatively, according to another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the base layer is a uniaxially stretched film.

[0022] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, further comprising a gas barrier layer interposed between the base layer and the sealant layer.

[0023] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the adhesive layer has gas barrier properties.

[0024] According to yet another aspect of the present invention, there is provided a laminate according to any of the above aspects, wherein the sealant layer is white in color.

[0025] According to yet another aspect of the present invention, there is provided a laminate according to any of the above aspects, in which the proportion of polyethylene is 90% by mass or more.

[0026] According to yet another aspect of the present invention there is provided a package including a laminate according to any of the above aspects.

[0027] According to yet another aspect of the present invention, there is provided a package according to the above aspect which is a stand-up pouch.

[0028] According to yet another aspect of the present invention, there is provided a packaged article including a package according to any of the above aspects and contents contained therein. Effect of the Invention

[0029] According to the present invention, there is provided a laminate which is mainly made of polyethylene and has excellent heat resistance. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a cross-sectional view illustrating a laminate according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view that illustrates a schematic diagram of a modified example of the laminate shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view that illustrates a laminate according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view that illustrates a schematic diagram of a modified example of the laminate shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view that illustrates a laminate according to a third embodiment of the present invention. [Figure 6]FIG. 6 is a cross-sectional view that diagrammatically illustrates a first modified example of the laminate shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view that diagrammatically illustrates a second modified example of the laminate shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view that illustrates a laminate according to a fourth embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view that illustrates a laminate according to a fifth embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view that diagrammatically illustrates a first modified example of the laminate shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view that diagrammatically illustrates a second modified example of the laminate shown in FIG. [Figure 12] FIG. 12 is a cross-sectional view that illustrates a laminate according to a sixth embodiment of the present invention. [Figure 13] FIG. 13 is a schematic diagram showing a packaging article according to a seventh embodiment of the present invention. [Figure 14] FIG. 14 is a schematic diagram showing a packaging article according to an eighth embodiment of the present invention. [Figure 15] FIG. 15 is a diagram illustrating a packaging article according to a ninth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific embodiments of any of the above aspects. The following items can be incorporated into each of the above aspects alone or in combination.

[0032] The embodiments described below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited by the materials, shapes, structures, etc. of the components described below. Various modifications can be made to the technical idea of ​​the present invention within the technical scope defined by the claims.

[0033] In addition, elements having the same or similar functions are given the same reference numerals in the drawings referred to below, and duplicated explanations are omitted. Therefore, matters mentioned in one embodiment can be applied to other embodiments unless otherwise specified. In addition, the drawings are schematic, and the relationship between dimensions in one direction and dimensions in another direction, the relationship between the dimensions of one member and the dimensions of another member, etc. may differ from the actual ones.

[0034] <1> First embodiment <1.1> Laminate FIG. 1 is a cross-sectional view illustrating a laminate according to a first embodiment of the present invention. The laminate 10A1 shown in FIG. 1 includes a base layer 1, a printed layer 4, an adhesive layer 3, and a sealant layer 2, in this order.

[0035] The laminate 10A1 has a polyethylene ratio of 90% by mass or more. Here, the polyethylene ratio in the laminate means the ratio of the total amount of polyethylene to the total amount of resin material in each layer constituting the laminate. By making the polyethylene ratio 90% by mass or more, high recyclability can be achieved.

[0036] <1.2> Base material layer The base layer 1 contains polyethylene. Preferably, the base layer 1 is made of polyethylene. The probe drop temperature of the base layer 1 is 180°C or higher. There is no particular upper limit to the probe drop temperature of the base layer 1. However, it is preferably 250°C or lower, and more preferably 220°C or lower.

[0037] As described above, the base layer 1 has a high probe drop temperature. A high probe drop temperature means that the base material has excellent heat resistance. Having excellent heat resistance suggests that a regular arrangement of the molecular chains that make up the base layer is formed. Examples of the formation of this regular arrangement include the formation of crystals (spherulites), which are a primary structure, and oriented crystallization, which is a secondary structure. In particular, the formation of a secondary structure, such as the latter oriented crystallization, is expected to not only improve heat resistance, but also improve impact resistance and puncture resistance due to the regularity of the molecular arrangement.

[0038] The probe descent temperature can be adjusted by the stretching conditions such as the stretch ratio of the base layer, as well as the film production conditions such as the density of the resin used, the type of comonomer, molecular weight, molecular weight distribution, and thermal history, and the film deposition method.

[0039] The polyethylene contained in the base layer 1 may be a homopolymer of ethylene or a copolymer of ethylene and another monomer. When the polyethylene is a copolymer of ethylene and another monomer, the proportion of ethylene in the copolymer is, for example, 80 mol % or more.

[0040] The other monomer is, for example, an α-olefin. According to one example, the α-olefin has a carbon number in the range of 3 to 20. Such an α-olefin is, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, or 6-methyl-1-heptene.

[0041] The polyethylene may be a copolymer of ethylene and one of vinyl acetate and acrylic esters.

[0042] The substrate layer 1 is, for example, high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or very low density polyethylene (VLDPE).

[0043] Here, high density polyethylene has a density of 0.942 g / cm 3 and medium density polyethylene has a density of 0.930 g / cm 3 More than 0.942g / cm 3 and low density polyethylene has a density of 0.910 g / cm 3 More than 0.930g / cm 3 Linear low density polyethylene has a density of 0.910 g / cm 3 More than 0.930cm 3 and ultra-low density polyethylene has a density of 0.910 g / cm 3 is less than. The density is a value obtained by a method in accordance with JIS K7112:1999.

[0044] The polyethylene contained in the base material layer 1 may be polyethylene derived from biomass. As the polyethylene derived from biomass, for example, Green Polyethylene (manufactured by Braskem) can be used.

[0045] Alternatively, the polyethylene contained in the base layer 1 may be polyethylene recycled by mechanical recycling. Here, mechanical recycling refers to decontaminating the polyethylene film by crushing collected polyethylene films and the like, cleaning the crushed films with an alkali to remove dirt and foreign matter on the film surface, and then drying the films at high temperature and reduced pressure to diffuse contaminants remaining inside the films.

[0046] Alternatively, the polyethylene contained in the base layer 1 may be polyethylene recycled by chemical recycling. The melting point of the base layer 1 is preferably within a range of 100° C. to 140° C., and more preferably within a range of 120° C. to 140° C. The melting point is a value obtained by a method in accordance with JIS K7121-1987.

[0047] Here, the probe drop temperature of the base layer 1 is a value obtained by a measurement method described later for the surface of the base layer 1 opposite to the surface facing the sealant layer 2. The measurement method for the probe drop temperature will be described in detail later.

[0048] The substrate layer 1 may be a non-stretched film or a stretched film. The substrate layer 1 is preferably a stretched film. When the substrate layer 1 is a stretched film, it is particularly excellent in heat resistance and strength. In addition, the substrate layer 1 is less likely to stretch, and printability is improved. In this specification, the term "film" does not include the concept of thickness.

[0049] When the base layer 1 is a stretched film, the base layer 1 may be a uniaxially stretched film or a biaxially stretched film. When a uniaxially stretched film is used as the base layer 1, the heat resistance during bag making, that is, the sealability described below, is improved. When a biaxially stretched film is used as the base layer 1, the drop strength of a packaged article using the laminate 10A as a packaging material is improved.

[0050] Whether a stretched film is uniaxially stretched or biaxially stretched can be determined by performing 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 orientation of molecular chains present on the film surface. An example of the measurement method is shown below.

[0051] First, an out-of-plane measurement is performed using a wide-angle X-ray diffraction device manufactured by Rigaku Corporation using the parallel beam method. The X-ray diffraction pattern of the film to be measured is obtained by scanning the diffraction angle range of 10° to 30° using 2θ / θ. αX-rays are collimated by a multilayer mirror and made incident on the base material layer 1. A scintillation detector equipped with a flat collimator is used as the light receiving unit.

[0052] From the obtained X-ray diffraction pattern, the peak area of ​​the crystalline component and the halo pattern area of ​​the amorphous component are determined, and the ratio of the peak area of ​​the crystalline component to the total area is calculated as the degree of crystallinity. When the film to be measured has a plurality of layers, the crystallinity of one of the outermost surfaces of the film is measured.

[0053] When the film to be measured is a polyethylene film, scanning at a diffraction angle range of 10° to 30° reveals two sharp crystalline peaks corresponding to the (110) and (200) planes, as well as a broad halo pattern of amorphous components.

[0054] In order to determine whether the film to be measured is a uniaxially stretched film or a biaxially stretched film, it is possible to use in-plane measurement by X-ray diffraction as described above. In this in-plane measurement, 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 angle θ and angle 2θ at which a diffraction peak corresponding to a specific crystal plane is detected in the above out-of-plane measurement, for example, the diffraction peak corresponding to the (110) plane of a polyethylene film, respectively, and in this state, the film to be measured is scanned in the in-plane direction to obtain a diffraction pattern.

[0055] When in-plane measurements are performed on a uniaxially stretched film that has been uniaxially stretched in the machine direction (MD), a diffraction pattern can be obtained that has a sharp diffraction peak corresponding to the (110) plane at an angle 2θ of about ±90°, assuming that the MD direction is defined as 0°. On the other hand, in the case of a biaxially stretched film, the high-order structure obtained by uniaxial stretching is disturbed by the second stretching, and the anisotropy is reduced, so a diffraction pattern having a sharp diffraction peak corresponding to this (110) plane cannot be obtained. Therefore, in-plane measurements can be cited as one method for distinguishing uniaxially stretched films from biaxially stretched films.

[0056] As described above, when a polymer film is uniaxially stretched, a higher-order structure appears. This higher-order structure is called a shish kebab structure. The shish kebab structure consists of a shish structure, which is an extended chain crystal, and a kebab structure, which is a lamellar crystal. In a uniaxially stretched film, this higher-order structure is arranged with a high degree of order, and therefore, the X-ray diffraction pattern obtained by the above measurement of the uniaxially stretched film contains a sharp diffraction peak. That is, when the above measurement is performed on a uniaxially stretched film, a clear diffraction peak appears. Note that a "clear diffraction peak" means a diffraction peak with a half-width of less than 10°.

[0057] In contrast, in the manufacture of biaxially stretched films, the film is stretched in a specific direction, and then stretched in a direction perpendicular to the first direction. Therefore, although the first stretching produces the above-mentioned high-order structure, this high-order structure is disturbed by the second stretching. Therefore, when the above-mentioned measurements are performed on a biaxially stretched film, the diffraction peaks in the resulting X-ray diffraction pattern are broad. In other words, when the above-mentioned measurements are performed on a biaxially stretched film, no clear diffraction peaks appear.

[0058] As described above, the X-ray diffraction patterns obtained by the above-mentioned measurements are different between uniaxially stretched films and biaxially stretched films, and therefore it is possible to determine whether a stretched film is a uniaxially stretched film or a biaxially stretched film based on the X-ray diffraction patterns.

[0059] The haze of the base layer 1 is preferably 20% or less, and more preferably 10% or less. The haze is a value obtained by a method in accordance with JIS K7136:2000.

[0060] The thickness of the base layer 1 is preferably in the range of 10 μm to 200 μm. The thickness of the base layer 1 is, for example, in the range of 10 μm to 50 μm, or in the range of 15 μm to 50 μm, or in the range of 12 μm to 35 μm. If the base layer 1 is too thin, the strength of the laminate 10A1 is likely to be reduced. Also, if the base layer 1 is too thick, the processability of the laminate 10A1 is likely to be reduced.

[0061] The substrate layer 1 is preferably surface-treated. This treatment can improve the adhesion between the substrate layer 1 and a layer adjacent to the substrate layer 1.

[0062] The method of the surface treatment is not particularly limited, and examples of the surface treatment include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0063] The base layer 1 may further contain additives, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0064] <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.

[0065] The sealant layer 2 may be transparent or opaque. In the latter case, the sealant layer 2 is preferably white. When the laminate 10A has a transparent sealant layer 2 and is used in a package, the contents are easily visible. When the laminate 10A has an opaque sealant layer 2 and is used in a package, the contents do not interfere with the visibility of the image displayed by the printing layer 4. In particular, the white sealant layer 2 improves the visibility of the image displayed by the printing layer 4.

[0066] <1.4>Printing layer The printed layer 4 is provided on the surface of the base layer 1 facing the sealant layer 2, that is, on the back surface of the base layer 1.

[0067] The printing ink used for 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 additives such as pigments, extender pigments, plasticizers, drying agents, and stabilizers are added to a conventionally used ink binder resin such as urethane-based, acrylic-based, nitrocellulose-based, rubber-based, and vinyl chloride-based inks. It is preferable to use an ink derived from biomass as the printing ink. As the ink, biomass ink containing a material derived from biomass can also be preferably used. In addition, a light-shielding ink can also be preferably used. Examples of the light-shielding ink include white ink, black ink, silver ink, and sepia ink.

[0068] Examples of printing methods that can be used include well-known printing methods such as offset printing, gravure printing, flexographic printing, and silk screen printing, and well-known coating methods such as roll coating, knife edge coating, and gravure coating.

[0069] The printed layer 4 may be provided at any position between the base layer 1 and the sealant layer 2. For example, when the laminate 10A further includes an intermediate layer described below, the printed layer 4 may be provided on either side of the intermediate layer. That is, the printed layer 4 may be provided between any layers. The printed layer 4 may be provided on the surface of the base layer 1, or may be omitted. The laminate 10A may also include multiple printed layers.

[0070] <1.5>Adhesive layer The adhesive layer 3 bonds the base material layer 1, on which the print layer 4 is provided, to the sealant layer 2. As an adhesive for forming the adhesive layer 3, for example, a general adhesive for dry lamination is used.

[0071] The adhesive layer 3 includes at least one type of adhesive. The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be a solventless adhesive or a solvent-based adhesive.

[0072] Examples of the adhesive include epoxy adhesives such as polyether adhesives, polyester adhesives, silicone adhesives, and polyamine adhesives, urethane adhesives, rubber adhesives, vinyl adhesives, silicone adhesives, epoxy adhesives, phenol adhesives, and olefin adhesives. Adhesives containing biomass components can also be used. The adhesive is preferably a polyamine adhesive or a urethane adhesive having gas barrier properties.

[0073] The adhesive layer 3 may be a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound. Such an adhesive layer 3 can further improve the oxygen barrier property and water vapor barrier property of the laminate 10A1.

[0074] 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 further preferably in the range of 1 to 5 μm.

[0075] The adhesive layer 3 can be formed by applying and drying on the sealant layer 2 using a conventional method such as a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, or a transfer roll coating method.

[0076] <1.6> Probe drop temperature measurement method The method for measuring the probe drop temperature will be described below. The probe descent temperature is a temperature obtained by measuring the rising and falling behavior of the probe, and is a temperature obtained by performing local thermal analysis.

[0077] To measure the tip drop temperature, an atomic force microscope (AFM) equipped with a nanothermal microscope consisting of a cantilever (probe) with a heating mechanism is used. In the measurement, a solid resin substrate is fixed on the sample stage as a sample. Next, the cantilever is brought into contact with the surface of the sample, and a certain force (contact pressure) is applied to the cantilever in contact mode, and the sample is heated by applying a voltage. This causes the sample surface to expand thermally, and the cantilever rises. If the voltage is increased to further increase the temperature of the cantilever, the sample surface softens and a large change in hardness is observed. At that time, the cantilever descends and penetrates the sample. The tip drop temperature is calculated from the relationship between the displacement of the cantilever and the voltage during this period. In other words, the temperature at which the position of the cantilever changes suddenly is the softening point of the sample. The temperature obtained by converting the voltage at this time is the softening temperature, or the tip drop temperature.

[0078] By performing such measurements, it is possible to know the softening temperature in the nanoscale region, rather than the average softening temperature of the entire sample, specifically, the softening temperature in the surface region of the sample.

[0079] As the atomic force microscope, the MPF-3D-SA (trade name) and Ztherm System (trade name) manufactured by Oxford Instruments Co., Ltd. are used. The atomic force microscope is not limited to this device in particular, and the Nano Thermal Analysis (trade name) series and nanoIR (trade name) series manufactured by Bruker Japan Co., Ltd. can also be used. Furthermore, the Nano Thermal Analysis (trade name) can be attached to an atomic force microscope manufactured by another manufacturer and used for measurement.

[0080] The cantilever used is AN2-200 (product name) manufactured by Anasys Instruments, Inc. The cantilever is not particularly limited to this, and other cantilevers may be used as long as they can sufficiently reflect the laser light and can be applied with a voltage.

[0081] The voltage range applied to the cantilever depends on the resin to be measured, but is preferably from 1 V to 10 V, and more preferably from 3 V to 8 V in order to minimize damage to the sample and achieve higher spatial resolution.

[0082] The measurable temperature range depends on the resin to be measured, but generally, the measurement start temperature is above room temperature, about 25° C., and the measurement end temperature is below about 400° C. The temperature range for calculating the probe drop temperature is preferably 25° C. or higher and 300° C. or lower.

[0083] In measuring the probe drop temperature, as described above, heat is applied to the sample with a constant contact pressure by the cantilever. To apply the contact pressure, the cantilever needs to be in contact with the sample, but the contact pressure must be at a level that does not destroy the surface of the sample. The spring constant of the cantilever is preferably 0.1 to 3.5 N / m, and is preferably 0.5 to 3.5 N / m in order to perform measurements in both tapping mode and contact mode. The contact pressure is preferably 0.1 to 3.0 V.

[0084] The temperature rise rate (voltage rise rate) of the cantilever depends on the heating mechanism of the cantilever, but is generally preferably 0.1 V / sec to 10 V / sec, and more preferably 0.2 V / sec to 5 V / sec.

[0085] As described above, when the sample surface is softened, the cantilever penetrates the sample and descends. The penetration depth of the cantilever is preferably 3 to 500 nm because it is necessary to have a size that allows the peak top of the softening curve to be recognized. If the penetration depth is large, the cantilever (probe) may be damaged, so the penetration depth of the cantilever is more preferably 5 to 100 nm.

[0086] The expansion curve and the softening curve may be approximated by a function as necessary, and the intersection of the approximate curves may be calculated to determine the probe descent start point and the probe descent temperature. Alternatively, an analysis method may be used in which the peak top of the displacement is used as the probe descent start point and the probe descent temperature. Alternatively, the probe descent start point and the probe descent temperature may be determined from the voltage when the displacement reaches a specific value from the steady state.

[0087] As described above, the probe drop temperature is converted from the voltage. A calibration curve can be used for this conversion. In order to obtain an accurate probe drop temperature, the calibration curve is created, for example, after the measurement of the sample is performed. Four types of calibration samples are used: polycaprolactone (melting point: 55°C), low-density polyethylene (LDPE, melting point 110°C), polypropylene (PP, melting point 164°C), and polyethylene terephthalate (PET, melting point 235°C). For each calibration sample, measurements are performed at least twice at different measurement positions, and the average voltage corresponding to the probe drop start point is calculated from these measurement results. Then, a calibration curve is created from the average voltages obtained for all calibration samples and their melting points. The probe drop temperature is obtained by referring to this calibration curve and the voltage obtained for the sample.

[0088] <1.7> Effects The above-described laminate 10A1 has excellent heat resistance, which will be described below.

[0089] The manufacture of packaging bags generally involves a process in which sealant layers of a laminate are brought into contact with each other, and the contacting portions are clamped with a jig and subjected to pressure and heat to thermally weld (heat seal) the contacting portions. The jig of the heat sealing machine is heated to a high temperature, and the surface of the base layer that directly contacts the jig is exposed to high temperatures. As a result, when polyethylene, which has poor heat resistance, is used for the base layer, problems such as the surface of the base layer being affected by heat and adhering to the jig may occur. For this reason, conventional laminates using polyethylene for the base layer have a narrow range of suitable bag-making temperatures, which has led to problems with poor productivity.

[0090] The inventors measured the above-mentioned probe drop temperature for various polyethylenes and found that when the probe drop temperature of the base layer 1 is 180°C or higher, the base layer 1 exhibits excellent heat resistance, and therefore the laminate 10A1 also exhibits excellent heat resistance, and in particular achieves good heat sealing suitability.

[0091] In the laminate 10A1, polyethylene, which is generally considered to have poor heat resistance, is used as the base layer 1. However, by setting the probe drop temperature of the base layer 1 to 180°C or higher, the temperature range of the heat sealing performed for bag making is expanded, and no decrease in productivity occurs.

[0092] Furthermore, the laminate 10A1 contains polyethylene at a rate of 90% by mass or more, and therefore the laminate 10A1 is also highly recyclable.

[0093] <1.8> Variations The laminate 10A1 can be modified in various ways. FIG. 2 is a cross-sectional view that shows a schematic diagram of a modified example of the laminate shown in FIG. 1. The laminate 10A2 shown in FIG. 2 is similar to the laminate 10A1 except that it further includes an inorganic compound layer 5 interposed between the base layer 1 and the printed layer 4. The inorganic compound layer 5 is a thin film made of an inorganic compound, for example, an inorganic oxide such as aluminum oxide or silicon oxide, and functions as a gas barrier layer that suppresses the transmission of oxygen and water vapor. The laminate 10A2 may include a coating layer described in the second embodiment instead of the inorganic compound layer 5. Alternatively, the laminate 10A2 may further include the above-mentioned coating layer between the inorganic compound layer 5 and the adhesive layer 3. The coating layer, or a combination of the coating layer and the inorganic compound layer 5, may also function as a gas barrier layer.

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

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

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

[0097] <2> Second embodiment <2.1> Laminate FIG. 3 is a cross-sectional view that illustrates a laminate according to a second embodiment of the present invention. The laminate 10B1 shown in Figure 3 is similar to the laminate 10A1, except that it further includes a protective layer 6 provided on the surface of the base material layer 1 and a coating layer 7 interposed between the base material layer 1 and the printing layer 4.

[0098] <2.2>Protective layer The protective layer 6 is an outermost layer facing the sealant layer 2 with the base layer 1 sandwiched therebetween. Here, the protective layer 6 covers the surface of the base layer 1.

[0099] According to one example, the protective layer 6 is made of a thermosetting resin. That is, the protective layer 6 is a thermosetting resin layer. The cured product of the thermosetting resin is not particularly limited as long as it has heat resistance. As the thermosetting resin, for example, urethane resin, polyester resin, polyamide resin, acrylic resin, and epoxy resin can be used alone or in combination.

[0100] In one embodiment, the protective layer 6 preferably contains a water-soluble polymer, and is also preferably an organic-inorganic composite layer further containing an organometallic compound.

[0101] Examples of the water-soluble polymer include polyvinyl alcohols, polysaccharides such as starch, methyl cellulose, carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyols. In one embodiment, the protective layer 6 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that the coating layer 7 may contain.

[0102] The protective layer 6 preferably contains at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or the hydrolysate thereof as an organometallic compound. Examples of the metal alkoxide include compounds represented by the general formula M(OR), such as tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3]. n Examples of the above-mentioned are represented by the following formula:

[0103] Moreover, the protective layer 6 preferably further contains, as the organometallic compound, at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0104] In one embodiment, the protective layer 6 can be formed using a coating liquid for forming the covering layer 7 .

[0105] The protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. When the thickness of the protective layer 6 is 0.3 μm or more, the effect of reducing heat damage is particularly large. However, if the protective layer 6 is made thick, the coating film made of the thermosetting resin is likely to be insufficiently dried or the productivity is reduced. Therefore, the thickness of the protective layer 6 is preferably 3 μm or less, and more preferably less than 3 μm.

[0106] <2.3> Covering layer The coating layer 7 functions as a barrier layer that suppresses the transmission of oxygen and water vapor. When high barrier properties are not required, the coating layer 7 can be omitted.

[0107] The coating layer 7 can be formed, for example, by coating. In this case, a coating liquid containing a resin such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, and epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may be added to the coating liquid.

[0108] Alternatively, the coating layer 7 is a film containing a hydroxyl-containing polymer and an organosilicon compound. The coating layer 7 may be, for example, an organic-inorganic composite layer containing a reaction product of hydrolysis and dehydration condensation of an alkoxide and a water-soluble polymer. This organic-inorganic composite layer may further contain a reaction product of a silane coupling agent.

[0109] Examples of alkoxides used in the formation of the organic-inorganic composite layer include alkoxides represented by the general formula M(OR), such as tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3]. n These may be used alone or in combination of two or more.

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

[0111] The water-soluble polymer contained in the organic-inorganic composite layer is not particularly limited, and examples thereof include polyvinyl alcohol-based polymers, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving the oxygen gas barrier property, the water-soluble polymer preferably contains a water-soluble polymer of polyvinyl alcohol-based 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 may have only a few percent of acetate groups remaining.

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

[0114] The silane coupling agent used in the organic-inorganic composite layer may be a silane coupling agent having an organic functional group. Such silane coupling agents may be ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. The silane coupling agent selected from these, its hydrolyzate, and their reaction product may be used alone or in combination of two or more.

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

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

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

[0118] The thickness of the coating layer 7 is preferably 50 nm or more and 1000 nm or less, and more preferably 100 nm or more and 500 nm or less. When the thickness of the coating layer 7 is 50 nm or more, there is a tendency that more sufficient gas barrier properties can be obtained, and when it is 1000 nm or less, there is a tendency that sufficient flexibility can be maintained.

[0119] <2.4> Effects The laminate 10B1 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 10B1 can achieve even better heat resistance, and in particular, better heat sealability. Therefore, when the above-described configuration is adopted for the laminate 10B1, the temperature range of heat sealing performed for bag making is expanded, and a decrease in productivity is further prevented.

[0120] That is, the laminate 10B1 has even better heat resistance, and is also excellent in recyclability.

[0121] <2.5> Variations The laminate 10B1 can be modified in various ways. Fig. 4 is a cross-sectional view that illustrates a modified example of the laminate shown in Fig. 3. The laminate 10B2 illustrated in Fig. 4 is similar to the laminate 10B1 except that it further includes the inorganic compound layer 5 between the base layer 1 and the coating layer 7.

[0122] In the laminate 10B2, the combination of the coating layer 7 and the inorganic compound layer 5 functions as a barrier layer. In the laminate 10B2, the coating layer 7 may be omitted.

[0123] The laminate 10B2, like the laminate 10B1, is also more excellent in heat resistance, and is also excellent in recyclability.

[0124] <3> Third embodiment <3.1> Laminate FIG. 5 is a cross-sectional view that illustrates a laminate according to a third embodiment of the present invention. 5 is similar to the laminate 10A1 except for the following points. That is, the laminate 10C1 does not include a printed layer 4, and further includes an intermediate layer 8. Moreover, the laminate 10C1 includes a first adhesive layer 3A and a second adhesive layer 3B instead of the adhesive layer 3.

[0125] <3.3> Sealant layer The sealant layer 2 contains polyethylene, similarly to the above-described base layer 1. By using such a configuration, it is possible to prepare a packaging material or the like that has sufficient strength and heat resistance and is also recyclable.

[0126] Examples of the resin that can be used to form the sealant layer 2 include ethylene-based resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer; blended resins of polyethylene and polybutene; and polypropylene-based resins such as propylene-ethylene random copolymer and propylene-ethylene block copolymer. These thermoplastic resins can be appropriately selected depending on the intended use and temperature conditions such as boiling treatment.

[0127] The sealant layer 2 can contain the above-mentioned additives to the extent that the properties described below for the laminate 10C1 are not impaired.

[0128] The thickness of the sealant layer 2 can be appropriately set in consideration of the shape of the packaging bag to be manufactured, the mass of the contents to be contained, and the like, and can be, for example, 30 to 150 μm.

[0129] The sealant layer 2 here is formed by bonding a sealant film to the intermediate layer 8 via an adhesive. The sealant layer 2 can also be formed by an extrusion lamination method or the like in which a thermoplastic resin is heated and melted, extruded into a curtain shape, and bonded to the intermediate layer 8. In this case, the second adhesive layer 3B may be omitted.

[0130] <3.4> Middle class The intermediate layer 8 is interposed between the base layer 1 and the sealant layer 2. The intermediate layer 8 contains polyethylene. In the laminate 10C1, the intermediate layer 8 has the above-mentioned probe drop temperature of 180° C. or higher. The intermediate layer 8 preferably has the above-mentioned probe drop temperature of 220° C. or lower. Such an intermediate layer 8 increases the recyclability of the laminate 10C1 and contributes to improving the strength, particularly the puncture strength.

[0131] The intermediate layer 8 having a probe drop temperature of 180° C. or more is preferably a stretched film. The stretched film may be a uniaxially stretched film or a biaxially stretched film.

[0132] In this embodiment, an intermediate layer having a probe drop temperature of 140° C. or more and less than 180° C. may be used. The strength of the laminate, particularly the drop strength, can be improved by using an intermediate layer having a probe drop temperature of 140° C. or more and less than 180° C. It is preferable that the intermediate layer having a probe drop temperature of 140° C. or more and less than 180° C. is a non-stretched film.

[0133] The polyethylene that can be used may be, for example, the polyethylene contained in the base layer 1 described above. Among the above, the polyethylene contained in the intermediate layer 8 is preferably high density polyethylene or medium density polyethylene from the viewpoints of strength, heat resistance, and suitability for stretching the film.

[0134] Intermediate layer 8 can contain the above-mentioned additives to the extent that the properties described below for laminate 10C1 are not impaired.

[0135] The thickness of the intermediate layer 8 is preferably 9 μm or more and 50 μm or less, and more preferably 12 μm or more and 30 μm or less.

[0136] Increasing the thickness of the intermediate layer 8 can increase the strength and heat resistance of the laminate 10C1, while decreasing the thickness of the intermediate layer 8 can improve the processability of the laminate 10C1.

[0137] As the intermediate layer 8, a layer produced by the above-mentioned T-die method or inflation method may be used, or a commercially available layer may be used.

[0138] <3.5>Adhesive layer The first adhesive layer 3A is interposed between the base layer 1 and the intermediate layer 8, bonding them together. The second adhesive layer 3B is interposed between the sealant layer 2 and the intermediate layer 8, bonding them together. These adhesive layers improve the adhesion between the layers.

[0139] As the adhesive for forming the first adhesive layer 3A and the second adhesive layer 3B, for example, a known adhesive for dry lamination can be used. The adhesive can be used without any particular limitation as long as it is an adhesive for dry lamination. Specific examples include two-component curing type ester adhesive, ether adhesive, and one-component curing type or two-component curing type urethane adhesive. The bonding between the base layer 1 and the intermediate layer 8, and the bonding between the sealant layer 2 and the intermediate layer 8 may be performed by a non-solvent dry lamination method using a solvent-free adhesive.

[0140] A gas barrier adhesive that exhibits gas barrier properties after curing can also be used as the adhesive for forming the first adhesive layer 3A and the second adhesive layer 3B. By using a gas barrier adhesive, the gas barrier properties of the laminate 10C1 can be improved. The oxygen permeability of the adhesive layer made of a gas barrier adhesive is 150 cc / m2 ·day·atm or less is preferable, and 100cc / m 2 ·day·atm or less is more preferable, and 80cc / m 2 ·day·atm or less is more preferable, and 50cc / m 2 By providing an adhesive layer with a low oxygen permeability, the gas barrier properties of the laminate 10C1 can be improved.

[0141] As described later, the laminate 10C1 can further include an inorganic compound layer. When a gas barrier adhesive is used, even if a minor crack or the like occurs in the inorganic compound layer, the gas barrier adhesive can be applied thereon to allow the gas barrier adhesive to enter the gaps generated in the inorganic compound layer, thereby suppressing a decrease in the gas barrier properties.

[0142] Examples of gas barrier adhesives include epoxy adhesives and polyester-polyurethane adhesives. Specific examples of gas barrier adhesives include "Maxive" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation.

[0143] When the first adhesive layer 3A and the second adhesive layer 3B are made of a gas barrier adhesive, their thickness is preferably 50 times or more the thickness of the inorganic compound layer. When the first adhesive layer 3A and the second adhesive layer 3B are made thicker, the effect of suppressing cracking of the inorganic compound layer is enhanced, and the gas barrier property of the laminate 10C1 is improved. When the first adhesive layer 3A and the second adhesive layer 3B are made thicker, the adhesive layers can be further provided with cushioning properties that absorb external impacts, and the inorganic compound layer can be prevented from cracking due to impacts. From the viewpoints of maintaining the flexibility of the laminate 10C1, processability, and cost, the thickness of the first adhesive layer 3A and the second adhesive layer 3B is preferably 300 times or less the thickness of the inorganic compound layer.

[0144] The thickness of the first adhesive layer 3A and the second adhesive layer 3B is, for example, 0.1 to 20 μm, preferably 0.5 to 10 μm, and more preferably 1 to 5 μm.

[0145] The adhesive can be applied by, for example, a bar coating method, a dipping method, a roll coating method, a gravure coating method, a reverse coating method, an air knife coating method, a comma coating method, a die coating method, a screen printing method, a spray coating method, or a gravure offset method. The temperature when drying the coating film of the adhesive can be, for example, 30 to 200°C, and preferably 50 to 180°C. The temperature when curing the coating film can be, for example, room temperature to 70°C, and preferably 30 to 60°C. By setting the temperature during drying and curing within the above ranges, it is possible to further suppress the occurrence of cracks in the inorganic compound layer, the first adhesive layer 3A, and the second adhesive layer 3B, and to develop excellent gas barrier properties.

[0146] From the viewpoint of preventing cracking of the inorganic compound layer 5, it is preferable that the first adhesive layer 3A or the second adhesive layer 3B is in direct contact with the inorganic compound layer, but another layer may be interposed between them.

[0147] <3.6> Effects In the above-described laminate 10C1, the probe drop temperature of the base layer 1 is within the above range. Therefore, the laminate 10C1 has excellent heat resistance, similar to the laminate 10A1.

[0148] Moreover, the laminate 10C1 includes an intermediate layer 8 having a probe drop temperature within the above range. The intermediate layer 8 increases the strength, particularly the puncture strength, of the laminate 10C1. Therefore, the laminate 10C1 is excellent in strength, particularly the puncture strength.

[0149] The laminate 10C1 has a polyethylene content of 90% by mass or more, which makes the laminate 10C1 highly recyclable.

[0150] Furthermore, laminates with a high proportion of polyethylene are weaker than other laminates, and therefore are often folded when used as packaging materials. The more often the laminate is folded, the higher the possibility of pinholes occurring, but laminate 10C1, which has excellent puncture strength, is less likely to develop pinholes.

[0151] <3.7> Variations The laminate 10C1 can be modified in various ways. Fig. 6 is a cross-sectional view that illustrates a first modified example of the laminate shown in Fig. 5. Fig. 7 is a cross-sectional view that illustrates a second modified example of the laminate shown in Fig. 5.

[0152] The laminate 10C2 shown in FIG. 6 and the laminate 10C3 shown in FIG. 7 are similar to the laminate 10C1 except that they further include an inorganic compound layer 5. In the laminate 10C2, the inorganic compound layer 5 is interposed between the first adhesive layer 3A and the intermediate layer 8. In the laminate 10C3, the inorganic compound layer 5 is interposed between the second adhesive layer 3B and the intermediate layer 8. That is, in the laminate 10C2, the inorganic compound layer 5 is provided on one side of the intermediate layer 8, and in the laminate 10C3, the inorganic compound layer 5 is provided on the other side of the intermediate layer 8. The inorganic compound layer 5 may be provided on both sides of the intermediate layer 8. The inorganic compound layer 5 may be interposed between the base layer 1 and the first adhesive layer 3A.

[0153] The inorganic compound layer 5 improves the gas barrier properties, specifically the oxygen barrier properties and water vapor barrier properties, of the laminate.

[0154] Examples of materials constituting the inorganic compound layer 5 include inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, tin oxide, zinc oxide, and indium oxide, and aluminum oxide or silicon oxide is particularly preferred because of its excellent productivity and excellent oxygen barrier property and water vapor barrier property in a high temperature or high humidity heat environment. The inorganic compound layer 5 may contain one of these materials alone or two or more of them in combination.

[0155] The thickness of the inorganic compound layer 5 is preferably 1 to 200 nm, and increasing the thickness improves the oxygen barrier property and water vapor barrier property. However, increasing the thickness increases the manufacturing cost and makes the layer more susceptible to cracks caused by external forces such as bending and pulling, which in turn makes the layer more susceptible to deterioration of the barrier property.

[0156] The thickness of the vapor-deposited film made of aluminum oxide is preferably 5 nm or more and 30 nm or less. When the thickness is 5 nm or more, sufficient gas barrier properties can be obtained. Furthermore, when the thickness is 30 nm or less, cracks caused by deformation due to internal stress of the thin film can be suppressed, and the deterioration of gas barrier properties can be suppressed. Note that, when the thickness exceeds 30 nm, the cost is likely to increase due to an increase in the amount of material used and a prolonged film formation time, and is therefore not preferable from an economical point of view. From the same viewpoint as above, the thickness of the vapor-deposited film made of aluminum oxide is more preferably 7 nm or more and 15 nm or less.

[0157] The thickness of the vapor-deposited film made of silicon oxide is preferably 10 nm or more and 50 nm or less. When the thickness is 10 nm or more, sufficient gas barrier properties can be obtained. Furthermore, when the thickness is 50 nm or less, the occurrence of cracks due to deformation caused by internal stress in the thin film can be suppressed, and the deterioration of gas barrier properties can be suppressed. Note that, when the thickness exceeds 50 nm, the cost is likely to increase due to an increase in the amount of material used and a prolonged film formation time, and is therefore not preferable from an economical point of view. From the same viewpoint as above, the thickness of the vapor-deposited film made of silicon oxide is more preferably 20 nm or more and 40 nm or less.

[0158] The inorganic compound layer 5 can be formed by a known film formation method such as vacuum deposition, sputtering, ion plating, plasma chemical vapor deposition (CVD), etc. From the viewpoint of productivity, a roll-up vacuum deposition method is particularly preferable.

[0159] The laminates 10C2 and 10C3 may include the coating layer described in the second embodiment instead of the inorganic compound layer 5. The laminate 10C2 may further include the coating layer between the inorganic compound layer 5 and the first adhesive layer 3A. The laminate 10C3 may further include the coating layer between the inorganic compound layer 5 and the second adhesive layer 3B. The coating layer, or a combination of the coating layer and the inorganic compound layer 5, may also function as a gas barrier layer.

[0160] The laminates 10C1, 10C2, and 10C3 may further include one or more of a printed layer, a protective layer, a light-shielding layer, and other functional layers, as necessary.

[0161] The printing layer can be provided at a position visible from the outside in the packaged state for the purpose of displaying information about the contents, identifying the contents, or improving the design of the packaging bag. The printing method and printing ink are not particularly limited, and can be appropriately selected from known printing methods and printing inks, taking into consideration printability on the film, design such as color tone, adhesion, and safety as a food container. As the ink, biomass ink containing a material derived from biomass can also be preferably used. In addition, light-shielding ink can also be preferably used. Examples of light-shielding ink include white ink, black ink, silver ink, and sepia ink.

[0162] Examples of printing methods include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. Among them, gravure printing is preferred from the viewpoints of productivity and high definition of the pattern. In order to improve the adhesion of the printing layer, the surface of the layer forming the printing layer may be subjected to various pretreatments such as corona treatment, plasma treatment, and frame treatment, or a coating layer such as an easy-adhesion layer may be provided.

[0163] The printed layer is provided, for example, on any of the surface of the base material layer 1, the back surface of the base material layer 1, the surface of the intermediate layer 8 facing the base material layer 1 (surface), and the surface of the intermediate layer 8 facing the sealant layer 2 (back surface).

[0164] In order to impart light-shielding properties to the laminate, a metal vapor deposition layer may be provided on the substrate, intermediate layer or sealant layer. An example of the metal vapor deposition layer is aluminum vapor deposition.

[0165] <4> Fourth embodiment <4.1> Laminate FIG. 8 is a cross-sectional view that illustrates a laminate according to a fourth embodiment of the present invention.

[0166] 8 is similar to the laminate 10C3, except that it further includes a printed layer 4 interposed between the base layer 1 and the first adhesive layer 3A, a protective layer 6 provided on the surface of the base layer 1, and a coating layer 7 interposed between the inorganic compound layer 5 and the second adhesive layer 3B. As the printed layer 4, those described in the first and third embodiments can be used. As the protective layer 6 and the coating layer 7, those described in the second embodiment can be used.

[0167] <4.2> Effects The above-mentioned laminate 10D1 has a probe drop temperature of the base layer 1 within the above range. The laminate 10D1 also includes a protective layer 6. Therefore, the laminate 10D1 can achieve even better heat resistance, and in particular, better heat sealability. Therefore, when the above-mentioned configuration is adopted for the laminate 10D1, the temperature range of the heat seal performed for bag making is expanded, and a decrease in productivity is further prevented.

[0168] Moreover, the laminate 10D1 includes an intermediate layer 8 having a probe drop temperature within the above range. The intermediate layer 8 increases the strength, particularly the puncture strength, of the laminate 10D1. Therefore, the laminate 10D1 is excellent in strength, particularly the puncture strength.

[0169] Furthermore, when the haze is small, the substrate layer 1 has excellent transparency, so that images such as patterns and characters displayed by the print layer 4 can be viewed with good visibility.

[0170] The laminate 10D1 has a polyethylene content of 90% by mass or more, and therefore has excellent recyclability.

[0171] <4.3> Variations The laminate 10D1 can be modified in various ways. For example, the inorganic compound layer 5 may be provided on the surface of the intermediate layer 8 instead of on the back surface of the intermediate layer 8. In this case, the covering layer 7 is provided so as to cover the inorganic compound layer 5.

[0172] It is possible to omit one of the inorganic compound layer 5 and the covering layer 7. When high barrier properties are not required, it is possible to omit both the inorganic compound layer 5 and the covering layer 7.

[0173] The printing layer 4 may be provided on the surface of the base layer 1, on the surface of the intermediate layer 8, or on the back surface of the intermediate layer 8. In any case, the images such as patterns and characters displayed by the printing layer 4 can be viewed with good visibility. The printing layer 4 may be omitted.

[0174] <5> Fifth embodiment.

[0175] <5.1> Laminate FIG. 9 is a cross-sectional view that illustrates a laminate according to a fifth embodiment of the present invention.

[0176] The laminate 10E1 shown in FIG. 9 is similar to the laminate 10C1, except that the probe drop temperature of the intermediate layer 8 is 180° C. or less. The probe drop temperature of the intermediate layer 8 is preferably less than 180° C. Also, the probe drop temperature of the intermediate layer 8 is preferably 140° C. or more. In the laminate 10E1, the intermediate layer 8 is preferably a non-stretched film. Such an intermediate layer 8 increases the strength of the laminate 10E1, particularly its drop strength.

[0177] In this embodiment, an intermediate layer having a probe drop temperature of 180° C. or more may be used. When an intermediate layer having a probe drop temperature in the above range is used, the strength of the laminate, particularly the piercing strength, can be improved. The intermediate layer having a probe drop temperature of 180° C. or more is preferably a stretched film.

[0178] <5.2> Effects In the above-described laminate 10E1, the probe drop temperature of the base layer 1 is within the above range. Therefore, the laminate 10E1 has excellent heat resistance, similar to the laminate 10A1.

[0179] Moreover, the laminate 10E1 includes an intermediate layer 8 having a probe drop temperature within the above range. This intermediate layer 8 increases the strength, particularly the drop strength, of the laminate 10E1. That is, in the laminate 10E1, when used in a package, the intermediate layer 8 located on the inner side of the base layer 1 is softer than the base layer 1. This structure is suitable for absorbing the impact that occurs when a packaged article using the laminate 10E1 as a packaging material is dropped. Therefore, a packaged article using the laminate 10E1 as a packaging material is unlikely to be damaged (broken bag) by being dropped. Therefore, the laminate 10E1 has excellent strength, particularly drop strength.

[0180] The laminate 10E1 contains polyethylene at a rate of 90% by mass or more, and therefore the laminate 10E1 is also excellent in recyclability.

[0181] <5.3> Variations The laminate 10E1 can be modified in various ways. Fig. 10 is a cross-sectional view that illustrates a first modified example of the laminate shown in Fig. 9. Fig. 11 is a cross-sectional view that illustrates a second modified example of the laminate shown in Fig. 9.

[0182] The laminate 10E2 shown in FIG. 10 and the laminate 10E3 shown in FIG. 11 are similar to the laminate 10E1 except that they further include the inorganic compound layer 5 described in the third embodiment. In the laminate 10E2, the inorganic compound layer 5 is interposed between the first adhesive layer 3A and the intermediate layer 8. In the laminate 10E3, the inorganic compound layer 5 is interposed between the second adhesive layer 3B and the intermediate layer 8. That is, in the laminate 10E2, the inorganic compound layer 5 is provided on one side of the intermediate layer 8, and in the laminate 10E3, the inorganic compound layer 5 is provided on the other side of the intermediate layer 8. The inorganic compound layer 5 may be provided on both sides of the intermediate layer 8. The inorganic compound layer 5 may be interposed between the base layer 1 and the first adhesive layer 3A.

[0183] The laminates 10E2 and 10E3 may include the coating layer described in the second embodiment instead of the inorganic compound layer 5. The laminate 10E2 may further include the coating layer between the inorganic compound layer 5 and the first adhesive layer 3A. The laminate 10E3 may further include the coating layer between the inorganic compound layer 5 and the second adhesive layer 3B. The coating layer, or a combination of the coating layer and the inorganic compound layer 5, may also function as a gas barrier layer.

[0184] The laminates 10E1, 10E2, and 10E3 may further include one or more of a printed layer, a protective layer, a light-shielding layer, and other functional layers, as necessary. The printed layer is, for example, the one described in the third embodiment.

[0185] <6> Sixth embodiment <6.1> Laminate FIG. 12 is a cross-sectional view that illustrates a laminate according to a sixth embodiment of the present invention.

[0186] The laminate 10F1 shown in Fig. 12 is similar to the laminate 10E3, except that it further includes a printed layer 4 interposed between the base layer 1 and the first adhesive layer 3A, a protective layer 6 provided on the surface of the base layer 1, and a coating layer 7 interposed between the inorganic compound layer 5 and the second adhesive layer 3B. As the printed layer 4, those described in the first and third embodiments can be used. As the protective layer 6 and the coating layer 7, those described in the second embodiment can be used.

[0187] <6.2> Effects The above-mentioned laminate 10F1 has a probe drop temperature of the base layer 1 within the above range. The laminate 10F1 also includes a protective layer 6. Therefore, the laminate 10F1 can achieve even better heat resistance, and in particular, better heat sealability. Thus, when the above-mentioned configuration is adopted for the laminate 10F1, the temperature range of the heat seal performed for bag making is expanded, and a decrease in productivity is further prevented.

[0188] Moreover, the laminate 10F1 includes an intermediate layer 8 having a probe drop temperature within the above range. The intermediate layer 8 increases the strength, particularly the drop strength, of the laminate 10F1. Therefore, the laminate 10F1 is excellent in strength, particularly in drop strength.

[0189] Furthermore, when the haze is small, the substrate layer 1 has excellent transparency, so that images such as patterns and characters displayed by the print layer 4 can be viewed with good visibility.

[0190] The laminate 10F1 contains polyethylene at a rate of 90% by mass or more, and therefore the laminate 10F1 is also excellent in recyclability.

[0191] <6.3> Variations The laminate 10F1 can be modified in various ways. For example, the inorganic compound layer 5 may be provided on the surface of the intermediate layer 8 instead of on the back surface of the intermediate layer 8. In this case, the covering layer 7 is provided so as to cover the inorganic compound layer 5.

[0192] It is possible to omit one of the inorganic compound layer 5 and the covering layer 7. When high barrier properties are not required, it is possible to omit both the inorganic compound layer 5 and the covering layer 7.

[0193] The printing layer 4 may be provided on the surface of the base layer 1, on the surface of the intermediate layer 8, or on the back surface of the intermediate layer 8. In any case, the images such as patterns and characters displayed by the printing layer 4 can be viewed with good visibility. The printing layer 4 may be omitted.

[0194] <7> Seventh embodiment FIG. 13 is a schematic diagram showing a packaging article according to a seventh embodiment of the present invention.

[0195] Packaged article 100A shown in FIG. 13 includes package 110A and contents contained therein.

[0196] The package 110A is a flat pouch. The package 110A includes a pair of main films. Each of the main films is one of the laminates described in the first to sixth embodiments, or is cut out from the laminate. The main films are overlapped with their sealant layers facing each other, and the peripheral portions are heat-sealed to each other. The package 110A has a notch in the heat-sealed portion as an easy-open structure.

[0197] The contents may be any of liquids, solids, and mixtures thereof, and may be, for example, food or medicine.

[0198] <8> Eighth embodiment FIG. 14 is a schematic diagram showing a packaging article according to an eighth embodiment of the present invention.

[0199] The packaged article 100B shown in Fig. 14 includes a package 110B and contents contained therein. The contents are, for example, similar to those described for the packaged article 100A.

[0200] The package 110B is a standing pouch. The package 110B includes a pair of a main film and a bottom film. Each of these films is one of the laminates described in the first to sixth embodiments or is cut out from the laminate.

[0201] The pair of main films are overlapped with their sealant layers facing each other, and the peripheral portions are heat-sealed to each other except for one end and the area nearby. The bottom film is folded in half to form a mountain fold when viewed from the sealant layer side, and is sandwiched between the pair of main films at the position of the one end so that the mountain fold faces the other end of the main film. The bottom film is heat-sealed to the pair of main films except for its central portion. The outer surfaces of the bottom films are bonded to each other at both sides of the bottom of the package 110B.

[0202] The package 110B has a notch as an easy-open structure at the portion where the main film is heat-sealed. The easy-open structure may be provided so that an upper corner of the packaged article 100B can be used as a mouth when the packaged article 100B is opened. Alternatively, the packaged article 100B may further include a mouth member and a lid body described in the ninth embodiment.

[0203] <9> Ninth embodiment FIG. 15 is a diagram illustrating a packaging article according to a ninth embodiment of the present invention.

[0204] The packaged article 100C shown in Fig. 15 includes a package 110C and contents contained therein. The contents are, for example, similar to those described for the packaged article 100A.

[0205] The packaging body 110C is a gusset-type pouch and includes a container body 110C1, a mouth member 110C2, and a lid body 110C3.

[0206] The container body 110C1 includes a pair of body films and a pair of side films.

[0207] The pair of main body films are overlapped with their sealant layers facing each other and sandwiching a part of the mouth member 110C2 at one end. The peripheral portions of the main body films are heat-sealed to the mouth member 110C2 at the one end and are heat-sealed to each other in the vicinity of the one end. The peripheral portions of the main body films are also heat-sealed to each other at the opposite end except for the regions on both sides.

[0208] Each of the side films is folded in half so as to form a mountain fold when viewed from the sealant layer side. These side films are sandwiched between a pair of main films on both sides of the main films so that the mountain folds face each other. Each of the side films has a part of its peripheral edge heat-sealed to one of the main films, and the remaining part of the peripheral edge heat-sealed to the other main film. In addition, the outer surfaces of each of the side films are bonded to each other at the upper and lower positions of the package 110C. The container body 110C1 may further include a bottom film.

[0209] As described above, the mouth member 110C2 is sandwiched between the body films and includes a portion where they are heat sealed. The mouth member 110C2 further includes a mouth portion protruding outward from the container body 110C1. The mouth portion has a substantially cylindrical shape and is provided with a male screw on the outer surface of the side wall. The lid body 110C3 has a cylindrical shape with a bottom. The lid body 110C3 has a female screw on the inner surface of the side wall and is screwed into the mouth portion of the mouth member 110C2. EXAMPLES

[0210] The results of tests carried out in relation to the present invention are described below.

[0211] (1) Test A (1.1) Manufacturing of Laminate (1.1.1) Example 1A The laminate 10A2 shown in FIG. 2 was produced by the following method. First, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. was prepared as a base layer. The method for measuring the probe drop temperature used in this example and the examples and comparative examples described below will be described later.

[0212] Next, one surface of the base layer was subjected to a corona treatment. Then, silicon oxide (SiO x A vapor-deposited film having a thickness of 40 nm was then formed. A pattern was then printed on the inorganic compound layer using gravure ink to form a printed layer.

[0213] Next, a dry lamination adhesive (urethane adhesive) was applied to the surface of the base layer on which the print layer was formed, and a linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) was attached to the base layer as a sealant layer via this adhesive layer. In this manner, a laminate was produced.

[0214] (1.1.2) Example 2A The laminate 10A1 shown in FIG. 1 was produced in the same manner as in Example 1A, except that no inorganic compound layer was provided.

[0215] (1.1.3) Example 3A Laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyamine-based gas barrier adhesive was used as the adhesive instead of the dry lamination adhesive (urethane-based adhesive).

[0216] (1.1.4) Example 4A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 25 μm and a probe drop temperature of 205° C. was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C.

[0217] (1.1.5) Example 5A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 25 μm and a probe drop temperature of 203° C. was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C.

[0218] (1.1.6) Example 6A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 20 μm and a probe drop temperature of 211° C. was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C.

[0219] (1.1.7) Example 7A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 30 μm and a probe drop temperature of 211° C. was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C.

[0220] (1.1.8) Example 8A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a linear low-density polyethylene resin (LLDPE) film having a thickness of 40 μm was used as the sealant layer instead of the linear low-density polyethylene resin (LLDPE) film having a thickness of 60 μm.

[0221] (1.1.9) Example 9A The laminate 10A2 shown in FIG. 2 was produced in the same manner as in Example 1A, except that a linear low-density polyethylene resin (LLDPE) film having a thickness of 120 μm was used as the sealant layer instead of a linear low-density polyethylene resin (LLDPE) film having a thickness of 60 μm.

[0222] (1.1.10) Example 10A Laminate 10A1 shown in FIG. 1 was produced in the same manner as in Example 2A, except that a polyamine-based gas barrier adhesive was used as the adhesive instead of the dry lamination adhesive (urethane-based adhesive).

[0223] (1.1.11) Example 11A Laminate 10A1 shown in FIG. 1 was produced in the same manner as in Example 2A, except that a urethane-based gas barrier adhesive was used as the adhesive instead of the dry lamination adhesive (urethane-based adhesive).

[0224] (1.1.12) Comparative Example 1A A laminate was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 40 μm and a probe drop temperature of 156° C. was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. (1.1.13) Comparative example 2A A laminate was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C.

[0225] (1.1.14) Comparative example 3A A laminate was produced in the same manner as in Example 1A, except that a polyethylene film having a thickness of 25 μm and a probe drop temperature of 164° C. was used as the base layer instead of a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C.

[0226] (1.2) Measurement and evaluation methods The substrate layer used in the production of the laminate was subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and it was examined whether the diffraction pattern obtained by this measurement had a sharp diffraction peak corresponding to the (110) plane.

[0227] The laminate was also evaluated for sealability, heat resistance, print visibility, and gas barrier property. The method for measuring the probe drop temperature and the methods for evaluating the sealability, heat resistance, print visibility, and gas barrier property are described below.

[0228] (1.2.1) Probe drop temperature measurement method The probe drop temperature was measured by the following method. The atomic force microscope used was an MPF-3D-SA (trade name) manufactured by Oxford Instruments Co., Ltd. The nanothermal microscope equipped with this was a Ztherm (trade name) manufactured by Oxford Instruments Co., Ltd. The cantilever (probe) used was an AN2-200 (trade name) manufactured by Anasys Instruments Co., Ltd.

[0229] In the measurement, first, the shape of the sample was measured in the AC mode in a field of view of 10 μm square. Next, the cantilever (probe) was moved 5 to 10 μm away from the sample in the Z direction. In this state, the detrend correction function of the device was activated in the contact mode under the conditions of a maximum applied voltage of 6 V and a heating rate of 0.5 V / s to correct the change in the deflection of the cantilever (probe) due to the voltage application. Then, in the contact mode, the cantilever was brought into contact with the sample so that the change in deflection between the cantilever and the sample was 0.2 V, and the sample was heated by applying a voltage to the cantilever under the conditions of a maximum applied voltage of 6 V and a heating rate of 0.5 V / s while keeping the deflection at a constant value. The Z displacement at this time was recorded, and the measurement was stopped when the Z displacement changed from rising to falling and fell 50 nm from the point of change. If the Z displacement did not drop by 50 nm from the change point and reached the maximum applied voltage, the maximum applied voltage during the Detrend correction and measurement was increased by 0.5 V, and the same operation as above was carried out again. The applied voltage at which the recorded Z displacement was maximized was converted to temperature with reference to the calibration curve described later. This measurement was carried out at 10 points within a 10 μm square field of view, and the average of the obtained temperatures was taken as the probe drop temperature.

[0230] In order to obtain a calibration curve for converting applied voltage to temperature, polycaprolactone (melting point 60°C), low-density polyethylene (melting point 112°C), polypropylene (melting point 166°C), and polyethylene terephthalate (melting point 255°C) were prepared as constituent samples. Here, the melting points of the calibration samples were the melting peak temperatures measured by a differential scanning calorimeter (DSC) at a heating rate of 5°C / min.

[0231] The same measurements were performed on each of these calibration samples. Note that the maximum applied voltage during detrend correction and measurement was 3.5 V for polycaprolactone, 5.5 V for low-density polyethylene, 6.5 V for polypropylene, and 7.8 V for polyethylene terephthalate.

[0232] Then, the relationship between the applied voltage at which the Z displacement was maximized in the measurement of the calibration sample and the melting point of the constituent sample was approximated by a cubic function using the least squares method to create a calibration curve.

[0233] (1.2.2) Sealing performance evaluation method A sample cut into a 10 cm square of the laminate was folded in half so that the sealant layer was on the inside, and heat-sealed using a heat seal tester. Specifically, first, the bottom seal temperature was set to 100°C, the top seal temperature was set to 120°C, and a pressure of 0.1 MPa was applied for 1 second. Then, the presence or absence of melting of the seal surface was confirmed, and the area of ​​the top surface of the folded sample where the heat seal bar was applied was observed. If the seal surface was not melted and the top surface of the sample was not melted, the bottom seal temperature was fixed at 100°C, and the top seal temperature was increased by 10°C at a time, and the same pressure and observation were performed as above, until at least one of the seal surface and the top surface of the sample was melted. Then, the sealability was evaluated according to the following criteria. A: There was no melting on the top surface of the sample, and there were no problems with the appearance. B: The upper surface of the sample was melted, and there was a problem with the appearance.

[0234] (1.2.3) Evaluation method for print visibility The pattern displayed by the print layer was visually observed from the substrate layer side, and the visibility was evaluated according to the following criteria. A: The pattern displayed by the printing layer was clearly visible. B: The pattern displayed by the printing layer was blurred and unclear.

[0235] (1.2.4) Gas barrier property evaluation method The laminate was boiled, and then the oxygen transmission rate (OTR) was measured at 30°C and 70% relative humidity. An oxygen transmission rate measuring device (OXTRAN-2 / 20, manufactured by MOCON) was used for the measurement. The oxygen transmission rate was then evaluated for gas barrier properties with reference to the following criteria. A: OTR is 10cc / m 2 ·day·atm. B: OTR is 10cc / m 2 ·day·atm or more.

[0236] (1.2.5) Heat resistance evaluation method A sample cut into a 10 cm square of the laminate was folded in half so that the sealant layer was on the inside. Next, the lower seal temperature of the heat seal tester was set to 30°C, and the upper seal temperature was set 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 seal surface was confirmed, and the area of ​​the upper surface of the folded sample that was touched with the heat seal bar was observed to see if it was attached to the heat seal bar, and the heat resistance was evaluated according to the following criteria. A: The upper surface of the sample did not adhere to the heat seal bar. B: The top surface of the sample adhered to the heat seal bar.

[0237] (1.3) Results The results of the above measurements and evaluations are summarized in Tables 1A and 1B below.

[0238] [Table 1A]

[0239] [Table 1B]

[0240] As shown in Tables 1A and 1B, all of the laminates in which the probe drop temperature of the base layer was 180° C. or higher had good sealability, heat resistance, and print visibility. In contrast, all of the laminates in which the probe drop temperature of the base layer was less than 180° C. had insufficient sealability, heat resistance, and visibility.

[0241] (2) Test B (2.1) Manufacturing of Laminate (2.1.1) Example 1B The laminate 10B2 shown in FIG. 4 was produced by the following method. First, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. was prepared as a base layer. As described later, in this example and the examples and comparative examples described below, the probe drop temperature was measured by the method described in (1.2.1).

[0242] Next, one side of the base layer was subjected to a corona treatment. Then, a polyamideimide resin was applied to the corona-treated side of the base layer to form a protective layer having a thickness of 0.5 μm. The non-volatile content of the coating liquid used to form the protective layer was 5 mass%.

[0243] Next, the other surface of the base layer was subjected to a corona treatment. Next, a silicon oxide (SiO x ) was formed to a thickness of 40 nm. Next, a coating liquid for forming a coating layer was applied to the inorganic compound layer to form a coating layer of an organic-inorganic mixture having a thickness of 0.3 μm. Then, a pattern was printed on the inorganic compound layer using gravure ink to form a printed layer.

[0244] Next, a dry lamination adhesive (urethane adhesive) was applied to the surface of the base layer on which the print layer was formed, and a linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) was attached to the base layer as a sealant layer via this adhesive layer. In this manner, a laminate was produced.

[0245] (2.1.2) Example 2B A laminate 10B2 shown in FIG. 4 was produced in the same manner as in Example 1B, except that the thickness of the protective layer was 1 μm.

[0246] (2.1.3) Example 3B A laminate was produced in the same manner as in Example 1B, except that no protective layer was provided.

[0247] (2.1.4) Example 4B The laminate 10B2 shown in Fig. 4 was produced in the same manner as in Example 1B, except that a protective layer of 0.5 µm in thickness was formed from an organic / inorganic mixture instead of forming a protective layer of 0.5 µm in thickness by applying a polyamideimide resin. The protective layer of the organic / inorganic mixture was formed by applying the above-mentioned coating liquid for forming a coating layer.

[0248] (2.1.5) Example 5B The laminate 10B2 shown in FIG. 4 was produced in the same manner as in Example 1B, except that instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin, a protective layer having a thickness of 0.5 μm was formed from a urethane-based resin.

[0249] (2.1.6) Example 6B The laminate 10B2 shown in FIG. 4 was produced in the same manner as in Example 1B, except that instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin, a protective layer having a thickness of 1 μm was formed from a urethane-based resin.

[0250] (2.1.7) Example 7B The laminate 10B2 shown in FIG. 4 was produced in the same manner as in Example 1B, except that a protective layer having a thickness of 1 μm was formed from an ethylene-vinyl alcohol copolymer (EVOH) instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin.

[0251] (2.1.8) Example 8B The laminate 10B2 shown in FIG. 4 was produced in the same manner as in Example 1B, except that instead of forming a protective layer having a thickness of 0.5 μm by applying a polyamideimide resin, a protective layer having a thickness of 1 μm was formed from an acrylic resin.

[0252] (2.1.9) Comparative example 1B A laminate was produced in the same manner as in Example 1B, except that no protective layer was provided, and instead of using a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. as the base layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 152° C. was used.

[0253] (2.2) Measurement and Evaluation Methods The substrate layer used in the production of the laminate was subjected to in-plane measurement by the wide-angle X-ray diffraction method described above, and it was examined whether the diffraction pattern obtained by this measurement had a sharp diffraction peak corresponding to the (110) plane.

[0254] The laminate was also evaluated for sealability, heat resistance, and print visibility. The method for measuring the probe drop temperature and the methods for evaluating the sealability, heat resistance, and print visibility are described below.

[0255] (2.2.1) Probe drop temperature measurement method The probe drop temperature was measured by the method described in (1.2.1).

[0256] (2.2.2) Sealing performance evaluation method A sample obtained by cutting out a laminate into a 10 cm square was folded in half so that the sealant layer was on the inside, and heat-sealed using a heat seal tester. Specifically, first, the bottom seal temperature was set to 100°C, the top seal temperature was set to 120°C, and a pressure of 0.1 MPa was applied for 1 second. Then, the presence or absence of melting of the sealed surface was confirmed, and the area of ​​the top surface of the folded sample where the heat seal bar was applied was observed. If no melting or poor appearance occurred on the top surface of the sample, the bottom seal temperature was fixed at 100°C, and the top seal temperature was increased by 10°C at a time, and the same pressure and observation as above were performed until melting or poor appearance occurred on the top surface of the sample. Then, the sealability was evaluated according to the following criteria.

[0257] A: When the sealing surface was melted, no melting or appearance defects occurred on the upper surface of the sample. B: Melting or defective appearance occurred on the top surface of the sample during or before the sealing surface melted.

[0258] (2.2.3) Evaluation method for print visibility The print visibility was evaluated by the method described in (1.2.3).

[0259] (2.2.4) Heat resistance evaluation method A sample cut into a 10 cm square of the laminate was folded in half so that the sealant layer was on the inside. Next, the lower seal temperature of the heat seal tester was set to 30°C, and the upper seal temperature was set 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 seal surface was confirmed, and the area of ​​the upper surface of the folded sample that was touched with the heat seal bar was observed to see if it was attached to the heat seal bar, and the heat resistance was evaluated according to the following criteria. A: The upper surface of the sample did not adhere to the heat seal bar. B: The top surface of the sample adhered to the heat seal bar. For the laminates having a protective layer, the heat resistance was further evaluated in the same manner as above, except that the top seal temperature was set to 190°C.

[0260] (2.3) Results The results of the above measurements and evaluations are summarized in Table 2 below.

[0261] [Table 2]

[0262] As shown in Table 2, all of the laminates in which the probe drop temperature of the base layer was 180° C. or higher had good heat resistance and print visibility. The laminates in which the probe drop temperature of the base layer was 180° C. or higher and had a protective layer also had excellent sealability. In contrast, the laminates in which the probe drop temperature of the base layer was less than 180° C. and did not have a protective layer had insufficient sealability, heat resistance, and visibility.

[0263] (3) Test C (3.1) Manufacturing of Laminate (3.1.1) Example 1C The laminate 10C2 shown in Fig. 6 was produced by the following method. In this example, a printed layer was provided between the base layer 1 and the first adhesive layer 3A.

[0264] First, a polyethylene film having a thickness of 25 μm and having one surface subjected to a corona treatment was prepared as a base layer. This polyethylene film had a density of 0.950 g / cm 3 The probe drop temperature was 211° C. As described later, in this example and the examples and comparative examples described below, the probe drop temperature was measured by the method described in (1.2.1). A pattern was printed on the corona-treated surface of this base layer using gravure ink to form a print layer.

[0265] As an intermediate layer, a polyethylene film having a thickness of 25 μm and having one surface subjected to a corona treatment was prepared. This polyethylene film had a density of 0.950 g / cm 3 The probe drop temperature was 211° C. On the corona-treated surface of the intermediate layer, a silicon oxide (SiO x) A vapor-deposited film was formed to a thickness of 10 nm.

[0266] Next, a dry lamination adhesive (urethane adhesive) was applied to the surface of the base layer on which the printed layer was formed and the back surface of the intermediate layer on which the inorganic compound layer was formed, and the coating was dried to form first and second adhesive layers, each 3 μm thick. Then, the base layer and the intermediate layer were bonded together so that the printed layer and the inorganic compound layer faced each other with the first adhesive layer sandwiched therebetween, and the intermediate layer was bonded to a linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) as a sealant layer via the second adhesive layer. In this manner, a laminate was produced.

[0267] (3.1.2) Example 2C 5 was produced in the same manner as in Example 1C, except that no inorganic compound layer was provided. In this example, a printed layer was provided between the base layer 1 and the first adhesive layer 3A, as in Example 1C.

[0268] (3.1.3) Example 3C The laminate 10C2 shown in Fig. 6 was produced in the same manner as in Example 1C, except that a polyamine-based gas barrier adhesive was used as the adhesive instead of the dry lamination adhesive (urethane adhesive). In this example, a printed layer was provided between the base layer 1 and the first adhesive layer 3A, as in Example 1C.

[0269] (3.1.4) Example 4C The laminate 10C2 shown in Fig. 6 was produced in the same manner as in Example 1C, except that the following polyethylene film was used as the base layer instead of the above polyethylene film having a probe drop temperature of 211°C. That is, in this example, the base layer has a thickness of 25 µm and a density of 0.950 g / cm 3 The probe drop temperature was 205° C., and a polyethylene film having one surface subjected to corona treatment was used. In this example, a printed layer was also provided between the base material layer 1 and the first adhesive layer 3A, as in Example 1C.

[0270] (3.1.5) Example 5C The laminate 10C2 shown in Fig. 6 was produced in the same manner as in Example 1C, except for the following: In this example, instead of using the above-mentioned polyethylene film having a probe drop temperature of 211°C as the base layer, a laminate having a thickness of 25 µm and a density of 0.950 g / cm 3 The probe drop temperature was 203° C., and a polyethylene film with one side subjected to corona treatment was used. In this example, instead of using the above-mentioned polyethylene film with a probe drop temperature of 211° C., a polyethylene film with a thickness of 25 μm and a density of 0.950 g / cm 3 The probe drop temperature was 205° C., and a polyethylene film having one surface subjected to corona treatment was used. In this example, a printed layer was also provided between the base material layer 1 and the first adhesive layer 3A, as in Example 1C.

[0271] (3.1.6) Example 6C The laminate 10E2 shown in Fig. 10 was produced in the same manner as in Example 1C, except for the following: In this example, instead of using the above-mentioned polyethylene film having a probe drop temperature of 211°C as the intermediate layer, a laminate having a thickness of 40 µm and a density of 0.949 g / cm 3 The probe drop temperature was 156° C., and a polyethylene film having one surface subjected to corona treatment was used. In this example, a printed layer was also provided between the base material layer 1 and the first adhesive layer 3A, as in Example 1C.

[0272] (3.1.7) Comparative example 1C Instead of using the above polyethylene film with a probe drop temperature of 211°C as the base layer, a polyethylene film with a thickness of 40 μm and a density of 0.949 g / cm 3 A laminate was prepared in the same manner as in Example 1C, except that a polyethylene film having a probe drop temperature of 156° C. and a corona treatment on one side was used.

[0273] (3.1.8) Comparative Example 2C A laminate was produced in the same manner as in Example 1C, except for the following: In this example, instead of using the above polyethylene film having a probe drop temperature of 211° C. as the substrate layer, a laminate having a thickness of 40 μm and a density of 0.949 g / cm 3 The probe drop temperature was 156° C., and a polyethylene film with one side subjected to corona treatment was used. In this example, instead of using the above-mentioned polyethylene film with a probe drop temperature of 211° C., a polyethylene film with a thickness of 40 μm and a density of 0.949 g / cm 3 The probe drop temperature was 156° C., and a polyethylene film with one side subjected to a corona treatment was used.

[0274] (3.2) Measurement and Evaluation Methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above. Then, it was examined whether the diffraction pattern obtained by this measurement had a sharp diffraction peak corresponding to the (110) plane.

[0275] The laminate was also evaluated for sealing property, heat resistance, print visibility, and gas barrier property. The laminate was also measured for piercing strength. The methods for measuring the probe drop temperature and piercing strength, and the methods for evaluating the sealing property, heat resistance, print visibility, and gas barrier property are described below.

[0276] (3.2.1) Probe drop temperature measurement method The probe drop temperature was measured by the method described in (1.2.1).

[0277] (3.2.2) Sealing performance evaluation method A sample of the laminate cut into a 10 cm square was folded in half with the sealant layer on the inside, 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 observed, and the sealability was evaluated according to the following criteria. A: There was no melting on the surface of the sample, and there were no problems with the appearance. B: The surface of the sample was melted, and there was a problem with the appearance.

[0278] (3.2.3) Evaluation method for print visibility The print visibility was evaluated by the method described in (1.2.3).

[0279] (3.2.4) Gas barrier property evaluation method The gas barrier properties were evaluated by the method explained in (1.2.4).

[0280] (3.2.5) Measurement method for puncture strength A needle with a radius of 0.5 mm and a hemispherical tip is pressed against the laminate from the base layer side at a speed of 50 mm / min, and the maximum force until the needle penetrates is measured. This measurement was performed multiple times, and the arithmetic average of the maximum forces was obtained as the penetration strength.

[0281] (3.2.6) Heat resistance evaluation method Heat resistance was evaluated by the method explained in (1.2.5).

[0282] (3.3) Results The results of the above measurements and evaluations are summarized in Table 3 below.

[0283] [Table 3]

[0284] As shown in Table 3, all of the laminates in which the probe drop temperature of the base layer was 180°C or higher had good sealing properties, heat resistance, and print visibility. In addition, all of the laminates in which the probe drop temperatures of both the base layer and the intermediate layer were 180°C or higher showed high piercing strength. In contrast, all of the laminates in which the probe drop temperature of the base layer was less than 180°C showed insufficient sealing properties, heat resistance, and visibility. In addition, all of the laminates in which the probe drop temperatures of both the base layer and the intermediate layer were less than 180°C showed low piercing strength.

[0285] (4) Test D (4.1) Manufacturing of Laminate (4.1.1) Example 1D The laminate 10D1 shown in FIG. 8 was produced by the following method. First, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. was prepared as a base layer. As described later, in this example and the examples and comparative examples described below, the probe drop temperature was measured by the method described in (1.2.1).

[0286] Next, one side of the base layer was subjected to a corona treatment. Then, a polyamideimide resin was applied to the corona-treated side of the base layer to form a protective layer having a thickness of 0.5 μm. The non-volatile content of the coating liquid used to form the protective layer was 5 mass%.

[0287] Next, the other surface of the base layer was subjected to a corona treatment. Next, a pattern was printed on the inorganic compound layer on the corona-treated surface of the base layer using gravure ink to form a print layer.

[0288] As an intermediate layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. was prepared. Next, one surface of the intermediate layer was subjected to a corona treatment. On the corona-treated surface of the intermediate layer, silicon oxide (SiO x ) was deposited to a thickness of 40 nm. Next, a coating liquid for forming a coating layer was applied to the inorganic compound layer to form a coating layer made of an organic-inorganic mixture and having a thickness of 0.3 μm.

[0289] Next, a dry lamination adhesive (urethane adhesive) was applied to the surface of the base layer on which the printed layer was formed and the surface of the coating layer, and the coating was dried to form first and second adhesive layers. The base layer and the intermediate layer were then bonded together so that the printed layer and the intermediate layer faced each other with the first adhesive layer sandwiched therebetween, and the intermediate layer and the sealant layer were bonded together so that the coating layer and the linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) which was the sealant layer faced each other with the second adhesive layer interposed therebetween. In this manner, a laminate was produced.

[0290] (4.1.2) Example 2D A laminate 10D1 shown in FIG. 8 was produced in the same manner as in Example 1D, except that the thickness of the protective layer was 1 μm.

[0291] (4.1.3) Example 3D A laminate 10D1 shown in FIG. 8 was produced in the same manner as in Example 1D, except that the thickness of the protective layer was 3 μm.

[0292] (4.1.4) Example 4D A laminate was produced in the same manner as in Example 1D, except that no protective layer was provided, and instead of using a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. as the intermediate layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. was used.

[0293] (4.1.5) Comparative Example 1D A laminate was produced in the same manner as in Example 1D, except for the following points. That is, in this example, no protective layer was provided. In addition, in this example, instead of using a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. as the base layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. was used. Furthermore, in this example, instead of using a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. as the intermediate layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. was used.

[0294] (4.2) Measurement and Evaluation Methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above. Then, it was examined whether the diffraction pattern obtained by this measurement had a sharp diffraction peak corresponding to the (110) plane.

[0295] The laminate was also evaluated for sealing property, heat resistance, print visibility, and recyclability. The laminate was also measured for piercing strength. The methods for measuring the probe drop temperature and piercing strength, and the methods for evaluating the sealing property, heat resistance, print visibility, and recyclability are described below.

[0296] (4.2.1) Probe drop temperature measurement method The probe drop temperature was measured by the method described in (1.2.1).

[0297] (4.2.2) Sealing performance evaluation method A sample obtained by cutting out a laminate into a 10 cm square was folded in half so that the sealant layer was on the inside, and heat-sealed using a heat seal tester. Specifically, first, the bottom seal temperature was set to 100°C, and the top seal temperature was set to 120°C, and a pressure of 0.1 MPa was applied for 1 second. Then, the presence or absence of melting of the sealed surface was confirmed, and the area of ​​the top surface of the folded sample where the heat seal bar was applied was observed. If melting or poor appearance occurred on the top surface of the sample, the bottom seal temperature was fixed at 100°C, and the top seal temperature was increased by 10°C at a time, and the same pressure and observation as above were performed until melting or poor appearance occurred on the top surface of the sample. Then, the temperature at which melting or poor appearance occurred on the top surface of the sample was recorded. In addition, the sealability was evaluated according to the following criteria.

[0298] A: When the sealing surface was melted, no melting or appearance defects occurred on the upper surface of the sample. B: Melting or defective appearance occurred on the top surface of the sample during or before the sealing surface melted.

[0299] (4.2.3) Evaluation method for print visibility The print visibility was evaluated by the method described in (1.2.3).

[0300] (4.2.4) Recyclability assessment method The ratio of polyethylene to the total amount of resin contained in the laminate was calculated, and the recyclability was evaluated based on this ratio with reference to the following criteria. A: The proportion of polyethylene was 90 mass % or more. B: The proportion of polyethylene was less than 90% by mass.

[0301] (4.2.5) Measurement method for puncture strength The puncture strength was measured by the method described in (3.2.5).

[0302] (4.2.6) Heat resistance evaluation method Heat resistance was evaluated by the method described in (2.2.4).

[0303] (4.3) Results The results of the above measurements and evaluations are summarized in Table 4 below.

[0304] [Table 4]

[0305] As shown in Table 4, all of the laminates in which the probe drop temperature of the base layer was 180°C or higher had good heat resistance and print visibility. The laminates in which the probe drop temperature of the base layer was 180°C or higher and had a protective layer also had excellent sealability. In addition, all of the laminates in which the probe drop temperature of both the base layer and the intermediate layer was 180°C or higher and had a protective layer showed high piercing strength. In contrast, all of the laminates in which the probe drop temperature of the base layer was less than 180°C had insufficient heat resistance and visibility. In addition, the laminates in which the probe drop temperature of both the base layer and the intermediate layer was less than 180°C showed low piercing strength.

[0306] (5) Test E (5.1) Manufacturing of Laminate (5.1.1) Example 1E The laminate 10E2 shown in Fig. 10 was produced by the following method. In this example, a printed layer was provided between the base layer 1 and the first adhesive layer 3A.

[0307] First, a polyethylene film having a thickness of 25 μm and having one surface subjected to a corona treatment was prepared as a base layer. This polyethylene film had a density of 0.950 g / cm 3 The probe drop temperature was 211° C. As described later, in this example and the examples and comparative examples described below, the probe drop temperature was measured by the method described in (1.2.1). A pattern was printed on the corona-treated surface of this base layer using gravure ink to form a print layer.

[0308] As an intermediate layer, a polyethylene film having a thickness of 40 μm and having one surface subjected to a corona treatment was prepared. This polyethylene film had a density of 0.949 g / cm 3 The probe drop temperature was 156°C. On the corona-treated surface of the intermediate layer, a silicon oxide (SiO x ) A vapor-deposited film was formed to a thickness of 10 nm.

[0309] Next, a dry lamination adhesive (urethane adhesive) was applied to the surface of the base layer on which the printed layer was formed and the back surface of the intermediate layer on which the inorganic compound layer was formed, and the coating was dried to form first and second adhesive layers, each 3 μm thick. Then, the base layer and the intermediate layer were bonded together so that the printed layer and the inorganic compound layer faced each other with the first adhesive layer sandwiched therebetween, and the intermediate layer was bonded to a linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) as a sealant layer via the second adhesive layer. In this manner, a laminate was produced.

[0310] (5.1.2) Example 2E 9 was produced in the same manner as in Example 1EC, except that no inorganic compound layer was provided. In this example, a printed layer was provided between the base layer 1 and the first adhesive layer 3A, as in Example 1E.

[0311] (5.1.3) Example 3E The laminate 10E2 shown in Fig. 10 was produced in the same manner as in Example 1E, except that a polyamine-based gas barrier adhesive was used as the adhesive instead of the dry lamination adhesive (urethane adhesive). In this example, a printed layer was provided between the base layer 1 and the first adhesive layer 3A, as in Example 1E.

[0312] (5.1.4) Example 4E The laminate 10E2 shown in Fig. 10 was produced in the same manner as in Example 1E, except for the following: In this example, instead of using the above-mentioned polyethylene film having a probe drop temperature of 211°C as the base layer, a laminate having a thickness of 25 µm and a density of 0.950 g / cm 3 The probe drop temperature was 205° C., and a polyethylene film with one side subjected to corona treatment was used. In this example, instead of using the above-mentioned polyethylene film with a probe drop temperature of 156° C., a polyethylene film with a thickness of 25 μm and a density of 0.950 g / cm 3 The probe drop temperature was 160° C., and a polyethylene film having one surface subjected to corona treatment was used. In this example, a printed layer was also provided between the base material layer 1 and the first adhesive layer 3A, as in Example 1E.

[0313] (5.1.5) Example 5E The laminate 10E2 shown in Fig. 10 was produced in the same manner as in Example 1E, except that the following polyethylene film was used as the base layer instead of the above polyethylene film having a probe drop temperature of 211°C. That is, in this example, the base layer has a thickness of 25 µm and a density of 0.950 g / cm 3The probe drop temperature was 203° C., and a polyethylene film having one surface subjected to corona treatment was used. In this example, a printed layer was also provided between the base material layer 1 and the first adhesive layer 3A, as in Example 1E.

[0314] (5.1.6) Example 6E The laminate 10C2 shown in Fig. 6 was produced in the same manner as in Example 1E, except for the following: In this example, instead of using the above-mentioned polyethylene film having a probe drop temperature of 156°C as the intermediate layer, a laminate having a thickness of 25 µm and a density of 0.950 g / cm 3 The probe drop temperature was 211° C., and a polyethylene film having one surface subjected to corona treatment was used. In this example, a printed layer was also provided between the base material layer 1 and the first adhesive layer 3A, as in Example 1E.

[0315] (5.1.7) Comparative Example 1E Instead of using the above polyethylene film with a probe drop temperature of 211°C as the base layer, a polyethylene film with a thickness of 40 μm and a density of 0.949 g / cm 3 A laminate was prepared in the same manner as in Example 1E, except that a polyethylene film having a probe drop temperature of 156° C. and a corona treatment on one side was used.

[0316] (5.1.8) Comparative Example 2E A laminate was produced in the same manner as in Example 1E, except for the following: In this example, instead of using the above polyethylene film having a probe drop temperature of 211° C. as the substrate layer, a polyethylene film having a thickness of 40 μm and a density of 0.949 g / cm 3 The probe drop temperature was 156° C., and a polyethylene film with one side subjected to corona treatment was used. In this example, instead of using the above-mentioned polyethylene film with a probe drop temperature of 156° C. as the intermediate layer, a polyethylene film with a thickness of 25 μm and a density of 0.950 g / cm 3 The probe drop temperature was 205° C., and a polyethylene film having one side subjected to a corona treatment was used.

[0317] (5.2) Measurement and Evaluation Methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above. Then, it was examined whether the diffraction pattern obtained by this measurement had a sharp diffraction peak corresponding to the (110) plane.

[0318] The laminate was also evaluated for sealing property, heat resistance, print visibility, and gas barrier property. The laminate was also measured for drop strength. The methods for measuring the probe drop temperature and drop strength, and the methods for evaluating the sealing property, heat resistance, print visibility, and gas barrier property are described below.

[0319] (5.2.1) Probe drop temperature measurement method The probe drop temperature was measured by the method described in (1.2.1).

[0320] (5.2.2) Sealing performance evaluation method The sealing performance was evaluated by the method described in (3.2.2).

[0321] (5.2.3) Evaluation method for print visibility The print visibility was evaluated by the method described in (1.2.3).

[0322] (5.2.4) Gas barrier property evaluation method The gas barrier properties were evaluated by the method explained in (1.2.4).

[0323] (5.2.5) Drop Strength Measurement Method The laminate was cut to a predetermined size, and the periphery was heat-sealed to prepare 10 bags. An opening was provided in each bag to insert the 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 a packaged article. Next, each packaged article 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 articles whose bags were broken within 50 times to the total number of packaged articles (10) was calculated as the drop strength.

[0324] (5.2.6) Heat resistance evaluation method Heat resistance was evaluated by the method explained in (1.2.5).

[0325] (5.3) Results The results of the above measurements and evaluations are summarized in Table 5 below.

[0326] [Table 5]

[0327] As shown in Table 5, all of the laminates in which the probe drop temperature of the base layer was 180°C or higher had good sealability, heat resistance, and print visibility. In addition, the laminates in which the probe drop temperature of the base layer was 180°C or higher and the probe drop temperature of the intermediate layer was less than 180°C had excellent drop strength. In contrast, all of the laminates in which the probe drop temperature of the base layer was less than 180°C had insufficient sealability, heat resistance, and visibility. In addition, the laminates in which the probe drop temperature of the intermediate layer was 180°C or higher showed low drop strength.

[0328] (6) Test F (6.1) Manufacturing of Laminates (6.1.1) Example 1F The laminate 10F1 shown in FIG. 12 was produced by the following method. First, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. was prepared as a base layer. As described later, in this example and the examples and comparative examples described below, the probe drop temperature was measured by the method described in (1.2.1).

[0329] Next, one side of the base layer was subjected to a corona treatment. Then, a polyamideimide resin was applied to the corona-treated side of the base layer to form a protective layer having a thickness of 0.5 μm. The non-volatile content of the coating liquid used to form the protective layer was 5 mass%.

[0330] Next, the other surface of the base layer was subjected to a corona treatment. Next, a pattern was printed on the inorganic compound layer on the corona-treated surface of the base layer using gravure ink to form a print layer.

[0331] As an intermediate layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. was prepared. Next, one surface of the intermediate layer was subjected to a corona treatment. On the corona-treated surface of the intermediate layer, a silicon oxide (SiO x ) was deposited to a thickness of 40 nm. Next, a coating liquid for forming a coating layer was applied to the inorganic compound layer to form a coating layer made of an organic-inorganic mixture and having a thickness of 0.3 μm.

[0332] Next, a dry lamination adhesive (urethane adhesive) was applied to the surface of the base layer on which the printed layer was formed and the surface of the coating layer, and the coating was dried to form first and second adhesive layers. The base layer and the intermediate layer were then bonded together so that the printed layer and the intermediate layer faced each other with the first adhesive layer sandwiched therebetween, and the intermediate layer and the sealant layer were bonded together so that the coating layer and the linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) which was the sealant layer faced each other with the second adhesive layer interposed therebetween. In this manner, a laminate was produced.

[0333] (6.1.2) Example 2F A laminate 10F1 shown in FIG. 12 was produced in the same manner as in Example 1F, except that the thickness of the protective layer was 1 μm.

[0334] (6.1.3) Example 3F A laminate 10F1 shown in FIG. 12 was produced in the same manner as in Example 1F, except that the thickness of the protective layer was 3 μm.

[0335] (6.1.4) Example 4F A laminate was produced in the same manner as in Example 1F, except that no protective layer was provided, and instead of using a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. as the intermediate layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. was used.

[0336] (6.1.5) Comparative Example 1F A laminate was produced in the same manner as in Example 1F, except for the following points. That is, in this example, no protective layer was provided. In addition, in this example, instead of using a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. as the base layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. was used. Furthermore, in this example, instead of using a polyethylene film having a thickness of 25 μm and a probe drop temperature of 160° C. as the intermediate layer, a polyethylene film having a thickness of 25 μm and a probe drop temperature of 211° C. was used.

[0337] (6.2) Measurement and Evaluation Methods The substrate layer and intermediate layer used in the production of the laminate were subjected to in-plane measurement by the wide-angle X-ray diffraction method described above. Then, it was examined whether the diffraction pattern obtained by this measurement had a sharp diffraction peak corresponding to the (110) plane.

[0338] The laminate was also evaluated for sealing property, heat resistance, print visibility, and recyclability. The laminate was also measured for drop strength. The methods for measuring the probe drop temperature and drop strength, and the methods for evaluating the sealing property, heat resistance, print visibility, and recyclability are described below.

[0339] (6.2.1) Probe drop temperature measurement method The probe drop temperature was measured by the method described in (1.2.1).

[0340] (6.2.2) Sealing performance evaluation method The sealing performance was evaluated by the method described in (4.2.2).

[0341] (6.2.3) Evaluation method for print visibility The print visibility was evaluated by the method described in (1.2.3).

[0342] (6.2.4) Recyclability assessment method Recyclability was evaluated using the method described in (4.2.4).

[0343] (6.2.5) Drop Strength Measurement Method The drop strength was measured by the method described in (5.2.5).

[0344] (6.2.6) Heat resistance evaluation method Heat resistance was evaluated by the method described in (2.2.4).

[0345] (6.3) Results The results of the above measurements and evaluations are summarized in Table 6 below.

[0346] [Table 6]

[0347] As shown in Table 6, all of the laminates in which the probe drop temperature of the base layer is 180°C or higher had good heat resistance and print visibility. The laminates in which the probe drop temperature of the base layer is 180°C or higher and which have a protective layer also had excellent sealability. The laminates in which the probe drop temperature of the base layer is 180°C or higher and the probe drop temperature of the intermediate layer is less than 180°C had excellent drop strength. In contrast, the laminates in which the probe drop temperature of the base layer is less than 180°C all had insufficient sealability, heat resistance, and visibility. The laminates in which the probe drop temperature of the intermediate layer is 180°C or higher showed low drop strength. [Explanation of symbols]

[0348] Reference Signs List: 1...base material layer, 2...sealant layer, 3...adhesive layer, 3A...first adhesive layer, 3B...second adhesive layer, 4...printed layer, 5...inorganic compound layer, 6...protective layer, 7...coating layer, 8...intermediate layer, 10A1...laminate, 10A2...laminate, 10B1...laminate, 10B2...laminate, 10C1...laminate, 10C2...laminate, 10C3...laminate, 10D1...laminate, 10E1...laminate, 10E2...laminate, 10E3...laminate, 10F1...laminate, 100A...packaged article, 100B...packaged article, 100C...packaged article, 110A...packaged body, 110B...packaged body, 110C...packaged body, 110C1...container body, 110C2...mouth member, 110C3...lid body.

Claims

1. a substrate layer, an adhesive layer, and a sealant layer in this order; the substrate layer and the sealant layer comprise polyethylene; the substrate layer is stretched and has a probe drop temperature of 180°C or higher; a printing layer provided on the back surface of the base material layer; an inorganic compound layer interposed between the base layer and the sealant layer; Further provided with The probe descent temperature is determined by using an atomic force microscope equipped with a nanothermal microscope consisting of a cantilever with a heating mechanism, first fixing a solid resin substrate as a sample to a sample stage, then contacting the cantilever with the surface of the sample, applying a certain force to the cantilever in contact mode, and applying a voltage to heat it, thereby thermally expanding the surface of the sample and raising the cantilever, and then increasing the voltage to further raise the temperature of the cantilever, thereby softening the surface of the sample and allowing the cantilever to penetrate into the sample, and the probe descent temperature is determined from the relationship between the displacement of the cantilever and the voltage during this process.

2. The laminate according to claim 1 , wherein the substrate layer has a probe drop temperature of 220° C. or less.

3. 2. The laminate according to claim 1, further comprising an intermediate layer containing polyethylene interposed between the substrate layer and the sealant layer.

4. 4. The laminate according to claim 3, wherein the intermediate layer has a probe drop temperature of 180° C. or less.

5. The laminate according to claim 4, wherein the intermediate layer has a probe drop temperature of 140°C or higher.

6. 4. The laminate according to claim 3, wherein the intermediate layer has a probe drop temperature of 180° C. or higher.

7. The laminate according to claim 6, wherein the intermediate layer has a probe drop temperature of 220°C or less.

8. The laminate according to claim 1 , further comprising a protective layer as an outermost layer facing the sealant layer with the base layer sandwiched therebetween.

9. The laminate according to claim 8 , wherein the protective layer is made of a thermosetting resin.

10. The laminate according to claim 1 , wherein the substrate layer is a biaxially stretched film.

11. The laminate according to claim 1 , wherein the substrate layer is a uniaxially stretched film.

12. A laminate as described in claim 1, wherein the adhesive layer is interposed between the inorganic compound layer and the sealant layer, the printing layer is interposed between the inorganic compound layer and the adhesive layer, and only the adhesive layer, the printing layer, and the inorganic compound layer are interposed between the substrate layer and the sealant layer.

13. The laminate according to claim 1 , wherein the adhesive layer has gas barrier properties.

14. The laminate of claim 1 , wherein the sealant layer is white.

15. 2. The laminate according to claim 1, wherein the proportion of polyethylene is 90% by mass or more.

16. A package comprising a laminate according to any one of claims 1 to 15.

17. 17. The package of claim 16, which is a stand-up pouch.

18. A packaged article comprising the package of claim 16 and contents contained therein.

Images