Laminates, packaging and packaged articles

Abstract

Provided is a laminate that primarily comprises polyethylene, and has excellent heat resistance. A laminate (10A1) comprises 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 a polyethylene, and the substrate layer (1) has a probe descent temperature of 180°C or higher.

Description

[Technical Field]

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

[0002] Packaging materials used in packaging bags and other packaging structures require various properties depending on their intended use. These properties include, for example, the strength required for the packaging structure, suitability for bag making, printability, transportability, and preservation of the contents. To meet these requirements, it was common practice to use packaging materials composed of 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 coating a dispersion containing an inorganic layered compound and a water-soluble polymer onto at least one surface of a base layer made of a thermoplastic resin, an overcoat layer containing a cationic resin and a resin having hydroxyl groups, an adhesive layer, and a sealant layer are sequentially laminated. 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 a circular economy, there has been a need for packaging materials with high recyclability. However, as mentioned above, conventional packaging materials are composed of different types of resin materials. Separating these resin materials from each other is difficult.

[0006] Furthermore, it is generally believed that packaging materials have high recyclability if the proportion of the main resin in the packaging material is 90% by mass or more. As mentioned above, most conventional packaging materials contain multiple types of resin materials and do not meet the above criteria.

[0007] Therefore, most of the packaging materials are currently not recycled.

[0008] Patent Document 3 describes a laminate using a stretched film made of polyethylene as a base material, provided with an adhesive layer and a heat-sealing layer made of polyethylene thereon, and provided with a vapor deposition layer on at least one of the between the base material and the adhesive layer and between the heat-sealing 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

Patent Document 2

Patent Document 3

Summary of the Invention

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

[0011] According to one aspect of the present invention, a laminate is provided which includes a base material layer, an adhesive layer and a sealant layer in this order, wherein the base material layer and the sealant layer contain polyethylene, and the base material layer has a probe drop temperature of 180 ° C or higher.

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

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

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

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

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

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

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

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

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

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

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

[0023] According to yet another aspect of the present invention, a laminate relating to any of the above aspects is provided, wherein the adhesive layer is gas barrier.

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

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

[0026] According to yet another aspect of the present invention, a packaging body is provided which includes a laminate relating to any of the above aspects.

[0027] According to yet another aspect of the present invention, a packaging body relating to the above aspect, which is a standing pouch, is provided.

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

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

[0030] [Figure 1] Figure 1 is a schematic cross-sectional view showing a laminate according to the first embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing one modified example of the laminate shown in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view showing a laminate according to a second embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing one modified example of the laminate shown in Figure 3. [Figure 5] Figure 5 is a schematic cross-sectional view showing a laminate according to a third embodiment of the present invention. [Figure 6] Figure 6 is a schematic cross-sectional view showing a first modified example of the laminate shown in Figure 5. [Figure 7] Figure 7 is a schematic cross-sectional view showing a second modified example of the laminate shown in Figure 5. [Figure 8] Figure 8 is a schematic cross-sectional view showing a laminate according to the fourth embodiment of the present invention. [Figure 9] Figure 9 is a schematic cross-sectional view showing a laminate according to the fifth embodiment of the present invention. [Figure 10] Figure 10 is a schematic cross-sectional view showing a first modified example of the laminate shown in Figure 9. [Figure 11] Figure 11 is a schematic cross-sectional view showing a second modified example of the laminate shown in Figure 9. [Figure 12] Figure 12 is a schematic cross-sectional view showing a laminate according to the sixth embodiment of the present invention. [Figure 13] Figure 13 is a schematic diagram showing a packaged article according to the seventh embodiment of the present invention. [Figure 14] Figure 14 is a schematic diagram showing a packaged article according to the eighth embodiment of the present invention. [Figure 15] Figure 15 is a schematic diagram showing a packaged article according to the ninth embodiment of the present invention. [Modes for carrying out the invention]

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

[0032] Furthermore, the embodiments shown below illustrate configurations for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited by the material, shape, and structure of the components described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the claims described in the claims.

[0033] Elements with similar or identical functions are denoted by the same reference numerals in the drawings referenced below, and redundant explanations are omitted. Therefore, matters mentioned in one embodiment can also be applied to other embodiments unless otherwise specified. Furthermore, the drawings are schematic, and the relationships between dimensions in one direction and dimensions in another, and the relationships between the dimensions of one component and the dimensions of other components, etc., may differ from reality.

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

[0035] Laminate 10A1 has a polyethylene content of 90% by mass or more. Here, the polyethylene content in the laminate refers to the ratio of the total amount of polyethylene to the total amount of resin material in each layer constituting the laminate. By setting the polyethylene content to 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 temperature drop of the base layer 1 is 180°C or higher. There is no particular upper limit to the probe temperature drop of the base layer 1, but it is preferably 250°C or lower, and more preferably 220°C or lower.

[0037] As described above, substrate layer 1 exhibits a high probe drop temperature. A high probe drop temperature indicates excellent heat resistance as a substrate. Excellent heat resistance suggests that a regular arrangement of molecular chains constituting the substrate layer is formed. This regular arrangement can be formed through the formation of primary structures such as crystals (spherulites) or secondary structures such as oriented crystallization. In particular, the formation of secondary structures, such as the latter oriented crystallization, can be expected to improve not only heat resistance but also impact resistance and puncture resistance due to the regularity of its molecular arrangement.

[0038] The probe temperature drop can be adjusted by various factors, including stretching conditions such as the elongation rate of the substrate layer, as well as film manufacturing conditions such as the density of the resin used, the type of comonomer, molecular weight, molecular weight distribution, and thermal history, and the film formation method.

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

[0040] Other monomers include, for example, α-olefins. For example, α-olefins have a carbon number in the range of 3 to 20. Such α-olefins include, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, or 6-methyl-1-heptene.

[0041] Polyethylene may be a copolymer of ethylene and one of vinyl acetate or acrylic acid ester.

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

[0043] Here, high-density polyethylene has a density of 0.942 g / cm³. 3 In summary, medium-density polyethylene has a density of 0.930 g / cm³. 3 More than 0.942g / cm 3 It is less than 0.910 g / cm³, and low-density polyethylene has a density of 0.910 g / cm³. 3 More than 0.930g / cm 3 The density of linear low-density polyethylene is less than 0.910 g / cm³. 3 The above is 0.930cm 3 Ultra-low density polyethylene has a density of less than 0.910 g / cm³. 3 It is less than. The density is a value obtained using a method compliant with JIS K7112:1999.

[0044] The polyethylene contained in the base layer 1 may be biomass-derived polyethylene. For example, green polyethylene (manufactured by Braskem) can be used as biomass-derived polyethylene.

[0045] Alternatively, the polyethylene contained in the base layer 1 may be polyethylene recycled by mechanical recycling. Here, mechanical recycling is a method of decontaminating polyethylene film by crushing the collected polyethylene film, then washing the crushed film with alkali to remove dirt and foreign matter from the film surface, and finally drying it at high temperature and under reduced pressure to diffuse any contaminants remaining inside the film.

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

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

[0048] The base material layer 1 may be an unstretched film or a stretched film. It is desirable that the base material layer 1 is a stretched film. When the base material layer 1 is a stretched film, it is particularly excellent in heat resistance and strength. Also, the elongation of the base material layer 1 is reduced and the printing suitability is improved. In this specification, the term "film" does not include the concept of thickness.

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

[0050] Whether the stretched film is a uniaxially stretched film or a biaxially stretched film can be determined by performing in-plane measurement by the wide-angle X-ray diffraction method as described below. The X-ray diffraction pattern obtained by this measurement contains information on the orientation degree of the molecular chains present on the film surface. An example of the measurement method is shown.

[0051] First, using a wide-angle X-ray diffractometer manufactured by Rigaku Corporation, out-of-plane measurement is performed by the parallel beam method. By performing a 2θ / θ scan in the range of diffraction angles from 10° to 30°, the X-ray diffraction pattern of the film to be measured is obtained. As the X-ray, CuK αUsing a beam, parallelized X-rays are incident onto the substrate layer 1 via a multilayer mirror. A scintillation detector with a flat plate 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 sum of these areas is calculated as the degree of crystallinity. If the film being measured has multiple layers, the degree of crystallinity of one of the outermost layers of the film is measured.

[0053] When the film being measured is a polyethylene film, scanning in the diffraction angle range of 10° to 30° reveals two sharp crystalline component peaks corresponding to the (110) and (200) planes, along with a broad amorphous component halo pattern.

[0054] To determine whether the film being measured is a uniaxially oriented film or a biaxially oriented film, as described above, in-plane measurement using X-ray diffraction can be used. 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 angles θ and 2θ at which diffraction peaks corresponding to specific crystal planes were detected in the out-of-plane measurement described above, for example, the diffraction peak corresponding to the (110) plane of polyethylene film. In this state, the film being measured is scanned in the in-plane direction to obtain the diffraction pattern.

[0055] When in-plane measurement is performed on a uniaxially oriented film stretched uniaxially in the mechanical direction (MD), if the MD direction is defined as 0°, a diffraction pattern can be obtained in which sharp diffraction peaks corresponding to the (110) plane are located at angles 2θ of approximately ±90°. On the other hand, in the case of a biaxially oriented film, the higher-order structure obtained by uniaxial stretching is disturbed by the second stretching, and the anisotropy is reduced, so a diffraction pattern with sharp diffraction peaks corresponding to the (110) plane cannot be obtained. Therefore, in-plane measurement can be cited as one method for distinguishing between uniaxially oriented films and biaxially oriented films.

[0056] As described above, when a polymer film is uniaxially stretched, a higher-order structure appears. This higher-order structure is called the shish-kebab structure. The shish-kebab structure consists of shish structures, which are elongated chain crystals, and kebab structures, which are lamellar crystals. In uniaxially stretched films, this higher-order structure is arranged with a high degree of order, and therefore, the X-ray diffraction pattern obtained by the above measurement on a uniaxially stretched film will contain sharp diffraction peaks. In other words, when the above measurement is performed on a uniaxially stretched film, clear diffraction peaks appear. Note that "clear diffraction peaks" refers to diffraction peaks with a full width at half maximum of less than 10°.

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

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

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

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

[0061] It is preferable that the base layer 1 is surface-treated. This treatment can improve the adhesion between the base layer 1 and the layer adjacent to it.

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

[0063] The base layer 1 may further contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0064] <1.3>Sealant layer The sealant layer 2 faces the substrate 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, the contents are easily visible when it is used as packaging. When the laminate 10A has an opaque sealant layer 2, the contents do not obstruct the visibility of the image displayed by the printed layer 4 when it is used as packaging. In particular, a white sealant layer 2 improves the visibility of the image displayed by the printed layer 4.

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

[0067] The printing ink used in the printing layer 4 is not particularly limited as long as it has adhesion to polyethylene. The printing layer 4 is composed of an ink in which various pigments, extender pigments, plasticizers, drying agents, and stabilizers are added to conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride. It is preferable to use a biomass-derived ink as the printing ink. Biomass inks containing biomass-derived materials can also be preferably used. Light-shielding inks can also be preferably used. Examples of light-shielding inks include white ink, black ink, silver ink, and sepia ink.

[0068] As for the printing method, well-known printing methods such as offset printing, gravure printing, flexographic printing, and screen printing, as well as well-known coating methods such as roll coating, knife-edge coating, and gravure coating, can be used.

[0069] The printed layer 4 may be provided at any position between the substrate layer 1 and the sealant layer 2. For example, if the laminate 10A further includes an intermediate layer described later, the printed layer 4 may be provided on any surface 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 substrate layer 1, or it may be omitted. Also, the laminate 10A may include multiple printed layers.

[0070] <1.5>Adhesive layer The adhesive layer 3 bonds the substrate layer 1, on which the printed layer 4 is provided, to the sealant layer 2. As the adhesive for forming the adhesive layer 3, for example, a general-purpose dry laminating adhesive is used.

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

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

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

[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 even more preferably in the range of 1 to 5 μm.

[0075] The adhesive layer 3 can be formed by applying and drying it on the sealant layer 2 using conventionally known methods such as the direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, fontein method, and transfer roll coating method.

[0076] <1.6>Method for measuring probe drop temperature The following describes the method for measuring the probe drop temperature. Probe drop temperature is the temperature obtained by measuring the upward and downward behavior of the probe, and is obtained by performing local thermal analysis.

[0077] To measure the probe drop temperature, an atomic force microscope (AFM) equipped with a nanothermal microscope consisting of a cantilever (probe) with a heating mechanism is used. For the measurement, first, a solid resin substrate is fixed to the sample stage. Next, the cantilever is brought into contact with the sample surface, and a constant force (contact pressure) is applied to the cantilever in contact mode, while simultaneously applying a voltage to heat it. This causes the sample surface to thermally expand, and the cantilever rises. Increasing the voltage further raises the cantilever temperature, causing the sample surface to soften and a significant change in hardness to be observed. At this point, the cantilever descends and penetrates the sample. The probe drop temperature is determined from the relationship between the cantilever displacement and the voltage during this process. That is, the temperature at which the cantilever position changes rapidly is the softening point of the sample. The temperature obtained by converting the voltage at this point is the softening temperature, i.e., the probe drop temperature.

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

[0079] For atomic force microscopy, we use the MPF-3D-SA (product name) and Ztherm system (product name) manufactured by Oxford Instruments Ltd. However, we are not limited to these instruments; Bruker Japan's Nano Thermal Analysis (product name) series and nanoIR (product name) series can also be used. Furthermore, it is possible to attach the Nano Thermal Analysis (product name) to atomic force microscopes from other manufacturers for measurement.

[0080] The cantilever used is the AN2-200 (product name) manufactured by Anasis Instruments. The cantilever is not limited to this one; other cantilevers may be used as long as they can adequately reflect the laser light and allow voltage to be applied.

[0081] The voltage range applied to the cantilever depends on the resin being measured, but is preferably between 1V and 10V. To minimize damage to the sample and achieve higher spatial resolution, a voltage range of 3V to 8V is more preferable.

[0082] The measurable temperature range depends on the resin being measured, but generally, the starting temperature for measurement is around 25°C or higher (room temperature), and the ending temperature is around 400°C or lower. For calculating the probe drop temperature, a temperature range of 25°C to 300°C is preferable.

[0083] In measuring the probe drop temperature, as described above, heat is applied to the sample while maintaining a constant contact pressure from the cantilever. To apply contact pressure, the cantilever must be in contact with the sample, but the pressure must be such that it does not damage the sample surface. The cantilever spring constant is preferably 0.1 to 3.5 N / m, and is preferable for performing measurements in both tapping and contact modes. The contact pressure is preferably 0.1 to 3.0 V.

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

[0085] As described above, when the sample surface softens, the cantilever penetrates the sample and descends. The amount of cantilever penetration must be large enough to recognize the peak top of the softening curve, so it is preferably 3 to 500 nm. If the penetration amount is too large, the cantilever (probe) may break, so the amount of cantilever penetration is more preferably 5 to 100 nm.

[0086] The expansion curve and the softening curve may be approximated by functions as needed, and the intersection point of the approximated curves may be calculated to determine the probe descent start point and 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 probe descent temperature. Alternatively, the probe descent start point and 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 calculated from the voltage. A calibration curve can be used for this calculation. To obtain an accurate probe drop temperature, the calibration curve should be created, for example, after performing measurements on the sample. Four types of samples are used for calibration: 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, two or more measurements are taken at different measurement positions, and the average voltage corresponding to the probe drop start point is determined from these measurement results. Then, a calibration curve is created from the average voltage 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> Effect The laminate 10A1 described above has excellent heat resistance. This will be explained below.

[0089] The manufacturing process of packaging bags generally involves bringing the sealant layers of a laminate into contact with each other, and then applying pressure and heat to the contact area by clamping it with a jig, thereby heat-sealing the contact point. The jig of the heat-sealing machine becomes hot, and the surface of the base layer that is in direct contact with the jig is exposed to high temperatures. As a result, if polyethylene, which has poor heat resistance, is used as the base layer, problems such as the surface of the base layer being affected by the heat and sticking to the jig may occur. Therefore, conventional laminates using polyethylene as the base layer have had the problem of having a narrow range of optimal bag-making temperatures and poor productivity.

[0090] The inventors measured the probe drop temperature for various types of polyethylene 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 sealability.

[0091] In laminate 10A1, polyethylene, which is generally said 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 for heat sealing performed for bag making is expanded, and no decrease in productivity occurs.

[0092] Furthermore, the laminate 10A1 has a polyethylene content of 90% by mass or more. Therefore, the laminate 10A1 also has excellent recyclability.

[0093] <1.8> Variation The laminate 10A1 can undergo various deformations. Figure 2 is a schematic cross-sectional view showing a modified example of the laminate shown in Figure 1. The laminate 10A2 shown in Figure 2 is the same as the laminate 10A1 except that it further includes an inorganic compound layer 5 interposed between the substrate layer 1 and the printing layer 4. The inorganic compound layer 5 is a thin film made of an inorganic compound, such as an inorganic oxide such as aluminum oxide or silicon oxide, and functions as a gas barrier layer that suppresses the permeation of oxygen and water vapor. The laminate 10A2 may include a coating layer, as 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, can also function as a gas barrier layer.

[0094] The laminate 10A2 also exhibits excellent heat resistance. Furthermore, since the inorganic compound layer 5 is substantially transparent, even if the inorganic compound layer 5 is placed between the substrate layer 1 and the printing layer 4, the image displayed by the printing layer 4 can be seen from the surface side. In addition, the laminate 10A2 also exhibits excellent recyclability.

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

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

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

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

[0099] The protective layer 6 is, in one example, 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 thermosetting resins, for example, urethane resin, polyester resin, polyamide resin, acrylic resin, and epoxy resin can be used individually 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 water-soluble polymers include polyvinyl alcohol-based polymers, polysaccharides such as starch, methylcellulose, and carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. In one embodiment, the protective layer 6 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that can be contained in the coating layer 7.

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

[0103] Furthermore, it is preferable that the protective layer 6 further contains, as an organometallic compound, at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

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

[0105] The protective layer 6 reduces thermal damage to the surface of the laminate during heat sealing. The effect of reducing thermal damage is particularly great when the thickness of the protective layer 6 is 0.3 μm or more. However, if the thickness of the protective layer 6 is increased, it becomes easier for the coating film made of thermosetting resin to not dry properly, or productivity decreases. 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 permeation of oxygen and water vapor. If high barrier performance is 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 solution containing resins such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, and epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may be added to this coating solution.

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

[0109] Examples of alkoxides used in forming organic-inorganic composite layers include tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3], which have the general formula M(OR). n Examples include those represented by [the symbols]. One of these may be used alone or in combination of two or more.

[0110] The total content of alkoxides, their hydrolysates, or their reaction products in the coating solution used to form an organic-inorganic composite layer may be, for example, 40% by mass or more, 50% by mass or more, or 65% by mass or more, from the viewpoint of oxygen barrier properties. Furthermore, the total content of alkoxides, their hydrolysates, or their reaction products in the above coating solution may be, for example, 70% by mass or less.

[0111] The water-soluble polymer contained in the organic-inorganic composite layer is not particularly limited and includes, for example, polysaccharides such as polyvinyl alcohol-based polymers, starch, methylcellulose, and carboxymethylcellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving oxygen gas barrier properties, it is preferable that the water-soluble polymer contains a polyvinyl alcohol-based water-soluble polymer. The number-average molecular weight of the water-soluble polymer is, for example, 40,000 to 180,000.

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

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

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

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

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

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

[0118] The thickness of the coating layer 7 is preferably 50 nm to 1000 nm, and more preferably 100 nm to 500 nm. When the thickness of the coating layer 7 is 50 nm or more, it tends to provide more sufficient gas barrier properties, and when it is 1000 nm or less, it tends to maintain sufficient flexibility.

[0119] <2.4> Effect 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. Accordingly, by adopting the above configuration for the laminate 10B1, the temperature range for heat sealing performed for bag making is expanded, and a decrease in productivity becomes less likely.

[0120] In other words, laminate 10B1 has even better heat resistance. Furthermore, laminate 10B1 also has excellent recyclability.

[0121] <2.5> Variant The laminate 10B1 can be deformed in various ways. Figure 4 is a schematic cross-sectional view showing one modified example of the laminate shown in Figure 3. The laminate 10B2 shown in Figure 4 is the same as the laminate 10B1 except that it further includes the inorganic compound layer 5 described above 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] Laminate 10B2, like laminate 10B1, has even better heat resistance. Furthermore, laminate 10B2 also boasts excellent recyclability.

[0124] <3> Third Embodiment <3.1> Laminate Figure 5 is a schematic cross-sectional view showing a laminate according to a third embodiment of the present invention. The laminate 10C1 shown in Figure 5 is the same as the laminate 10A1, except for the following: Laminate 10C1 does not include the printed layer 4, but further includes an intermediate layer 8. Also, 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, like the base layer 1 described above, contains polyethylene. This configuration allows for the creation of packaging materials that possess sufficient strength and heat resistance, and are also recyclable.

[0126] As the resin constituting the sealant layer 2, for example, 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; a blend resin of polyethylene and polybutene; or polypropylene-based resins such as propylene-ethylene random copolymer and propylene-ethylene block copolymer can be used. These thermoplastic resins can be appropriately selected depending on the application and temperature conditions such as boiling treatment.

[0127] The sealant layer 2 may contain the above-mentioned additives to the extent that they do not impair the properties described for the laminate 10C1.

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

[0129] In this case, the sealant layer 2 is formed by laminating a sealant film to the intermediate layer 8 via an adhesive. The sealant layer 2 can also be formed by an extrusion lamination method, in which a thermoplastic resin is heated and melted, extruded in a curtain-like manner, and then laminated 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 material layer 1 and the sealant layer 2. The intermediate layer 8 contains polyethylene. In the laminate 10C1, the intermediate layer 8 has a probe drop temperature of 180°C or higher. Preferably, the intermediate layer 8 has a probe drop temperature of 220°C or lower. Such an intermediate layer 8 enhances the recyclability of the laminate 10C1 and contributes to improving its strength, particularly its puncture resistance.

[0131] The intermediate layer 8, which has a probe drop temperature of 180°C or higher, is preferably a stretched film. The stretched film may be a uniaxially oriented film or a biaxially oriented film.

[0132] In this embodiment, an intermediate layer with a probe drop temperature of 140°C or higher and less than 180°C may be used. By using an intermediate layer with a probe drop temperature of 140°C or higher and less than 180°C, the strength of the laminate, particularly its drop strength, can be improved. It is preferable that the intermediate layer with a probe drop temperature of 140°C or higher and less than 180°C is an unstretched film.

[0133] As for polyethylene, for example, the polyethylene contained in the base layer 1 can be the one described above. Among the polyethylenes described above, the polyethylene contained in the intermediate layer 8 is preferably high-density polyethylene or medium-density polyethylene, from the viewpoint of strength, heat resistance and suitability of film stretching.

[0134] The intermediate layer 8 may contain the above-mentioned additives to the extent that they do not impair the properties described for the laminate 10C1.

[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 improve the strength and heat resistance of the laminate 10C1. Conversely, decreasing the thickness of the intermediate layer 8 can improve the processability of the laminate 10C1.

[0137] The intermediate layer 8 may be one prepared by the T-die method or inflation method described above, or it may be one that is commercially available.

[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] For example, known dry laminating adhesives can be used as adhesives for forming the first adhesive layer 3A and the second adhesive layer 3B. Any dry laminating adhesive is acceptable and not particularly limited. Specific examples include two-component curing ester-based adhesives, ether-based adhesives, and one-component or two-component curing urethane-based adhesives. The bonding of the substrate layer 1 to the intermediate layer 8, and the bonding of the sealant layer 2 to the intermediate layer 8, may be performed by a non-solvent dry lamination method using a solvent-free adhesive.

[0140] As the adhesive for forming the first adhesive layer 3A and the second adhesive layer 3B, a gas barrier adhesive that exhibits gas barrier properties after curing can also be used. 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 the gas barrier adhesive is 150 cc / m².2 It is preferable that the pressure be less than or equal to 100cc / m³. 2 It is more preferable that it be less than or equal to 80cc / m². 2 It is even more preferable that it be less than or equal to 50cc / m². 2 It is particularly preferable that the oxygen permeability is less than or equal to 1 / day·atm. Providing an adhesive layer with low oxygen permeability can improve the gas barrier properties of the laminate 10C1.

[0141] Furthermore, as will be described later, the laminate 10C1 may further include an inorganic compound layer. When a gas barrier adhesive is used, even if minor cracks occur in the inorganic compound layer, applying the gas barrier adhesive on top of it allows the gas barrier adhesive to penetrate into the gaps in the inorganic compound layer, thereby suppressing a decrease in gas barrier properties.

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

[0143] When the first adhesive layer 3A and the second adhesive layer 3B are made of gas barrier adhesives, their thickness is preferably 50 times or more the thickness of the inorganic compound layer. Increasing the thickness of the first adhesive layer 3A and the second adhesive layer 3B enhances the effect of suppressing cracking of the inorganic compound layer and improves the gas barrier properties of the laminate 10C1. Increasing the thickness of the first adhesive layer 3A and the second adhesive layer 3B further imparts cushioning properties to these adhesive layers to mitigate external impacts, preventing the inorganic compound layer from cracking due to impact. From the viewpoint of maintaining the flexibility of the laminate 10C1, processability, and cost, it is preferable that the thickness of the first adhesive layer 3A and the second adhesive layer 3B is 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 methods such as bar coating, dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, or gravure offset coating. The temperature for drying the adhesive film can be, for example, 30 to 200°C, with 50 to 180°C being preferred. The temperature for curing the above film can be, for example, room temperature to 70°C, with 30 to 60°C being preferred. By keeping the drying and curing temperatures within the above ranges, crack formation in the inorganic compound layer, the first adhesive layer 3A, and the second adhesive layer 3B can be further suppressed, and excellent gas barrier properties can be achieved.

[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 and the inorganic compound layer are in direct contact, but other layers may be interposed between them.

[0147] <3.6> Effect The laminate 10C1 described above has a probe temperature drop within the above range for the base layer 1. Therefore, the laminate 10C1, like the laminate 10A1, has excellent heat resistance.

[0148] Furthermore, the laminate 10C1 includes an intermediate layer 8 in which the probe temperature drop is within the above range. This intermediate layer 8 enhances the strength of the laminate 10C1, particularly its puncture strength. Therefore, the laminate 10C1 has excellent strength, especially puncture strength.

[0149] Furthermore, the laminate 10C1 has a polyethylene content of 90% by mass or more. Therefore, the laminate 10C1 also has excellent recyclability.

[0150] Furthermore, laminates with a high polyethylene content are less rigid compared to other laminates, and therefore are more likely to be bent when used as packaging material. Increased bending increases the likelihood of pinhole formation, but laminate 10C1, which has excellent puncture strength, is less prone to developing pinholes.

[0151] <3.7> Modified Example The laminate 10C1 is capable of various deformations. Figure 6 is a schematic cross-sectional view showing a first modified example of the laminate shown in Figure 5. Figure 7 is a schematic cross-sectional view showing a second modified example of the laminate shown in Figure 5.

[0152] Laminate 10C2 shown in Figure 6 and laminate 10C3 shown in Figure 7 are the same as laminate 10C1, except that they further include an inorganic compound layer 5. In laminate 10C2, the inorganic compound layer 5 is interposed between the first adhesive layer 3A and the intermediate layer 8. In laminate 10C3, the inorganic compound layer 5 is interposed between the second adhesive layer 3B and the intermediate layer 8. That is, in laminate 10C2, the inorganic compound layer 5 is provided on one side of the intermediate layer 8, and in 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 also be interposed between the base material layer 1 and the first adhesive layer 3A.

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

[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. Aluminum oxide or silicon oxide are particularly preferred because they offer excellent productivity and superior oxygen barrier and water vapor barrier properties in high-temperature or high-humidity environments. The inorganic compound layer 5 may contain one of these materials alone or a combination of two or more.

[0155] The thickness of the inorganic compound layer 5 is preferably 1 to 200 nm, and increasing the thickness improves oxygen barrier properties and water vapor barrier properties. However, increasing the thickness increases manufacturing costs and makes the layer more susceptible to cracking due to external forces such as bending and pulling, which in turn makes it more prone to deterioration of barrier properties.

[0156] The thickness of the vapor-deposited aluminum oxide film is preferably between 5 nm and 30 nm. A thickness of 5 nm or more provides sufficient gas barrier properties. A thickness of 30 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 30 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 7 nm or more and 15 nm is more preferable for the vapor-deposited aluminum oxide film.

[0157] The thickness of the silicon dioxide vapor-deposited film is preferably between 10 nm and 50 nm. A thickness of 10 nm or more provides sufficient gas barrier properties. A thickness of 50 nm or less suppresses crack formation due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. However, a thickness exceeding 50 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer film formation times. From the same viewpoint as above, a thickness of 20 nm or more and 40 nm is more preferable for the silicon dioxide vapor-deposited film.

[0158] The inorganic compound layer 5 can be formed by known film deposition methods such as vacuum deposition, sputtering, ion plating, and plasma chemical vapor deposition (CVD). In terms of productivity, the roll-type vacuum deposition method is particularly preferred.

[0159] Laminates 10C2 and 10C3 may include the coating layer described in the second embodiment instead of the inorganic compound layer 5. Laminate 10C2 may further include the coating layer between the inorganic compound layer 5 and the first adhesive layer 3A. 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, can also function as a gas barrier layer.

[0160] The laminates 10C1, 10C2, and 10C3 may further include one or more printing layers, protective layers, light-shielding layers, and other functional layers, as needed.

[0161] The printed layer can be placed in a position visible from the outside of the package 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 factors such as suitability for printing on the film, design aspects such as color tone, adhesion, and safety as a food container. Biomass inks containing biomass-derived materials can also be preferably used as inks. Light-shielding inks can also be preferably used. Examples of light-shielding inks 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 these, gravure printing is preferred from the viewpoint of productivity and high resolution of the image. To improve the adhesion of the printed layer, various pretreatments such as corona treatment, plasma treatment, and flame treatment may be applied to the surface of the layer forming the printed layer, or a coating layer such as an easy-adhesion layer may be provided.

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

[0164] Furthermore, as a method for imparting light-shielding properties to the laminate, a metal vapor-deposited layer can be provided on the substrate, intermediate layer, or sealant layer. Aluminum vapor deposition is an example of such a metal vapor-deposited layer.

[0165] <4> Fourth Embodiment <4.1> Laminate Figure 8 is a schematic cross-sectional view showing a laminate according to the fourth embodiment of the present invention.

[0166] The laminate 10D1 shown in Figure 8 is the same as the laminate 10C3, except that it further includes a printing 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. The printing layer 4 can be the one described in the first and third embodiments. The protective layer 6 and the coating layer 7 can be the ones described in the second embodiment.

[0167] <4.2> Effects The laminate 10D1 described above has a probe drop temperature of the base layer 1 within the above range. Furthermore, the laminate 10D1 includes a protective layer 6. Therefore, the laminate 10D1 can achieve even better heat resistance, and in particular, better heat sealability. Accordingly, by adopting the above configuration for the laminate 10D1, the temperature range for heat sealing performed for bag making is expanded, and a decrease in productivity becomes less likely.

[0168] Furthermore, the laminate 10D1 includes an intermediate layer 8 whose probe temperature drop is within the above range. This intermediate layer 8 enhances the strength of the laminate 10D1, particularly its puncture resistance. Therefore, the laminate 10D1 has excellent strength, especially puncture resistance.

[0169] Furthermore, when the haze is low, the substrate layer 1 exhibits excellent transparency. Therefore, in this case, images such as patterns and characters displayed by the printed layer 4 can be viewed with good visibility.

[0170] Furthermore, the laminate 10D1 has a polyethylene content of 90% by mass or more. Therefore, the laminate 10D1 also has excellent recyclability.

[0171] <4.3> Modified Examples The laminate 10D1 can undergo various deformations. 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 coating layer 7 is provided so as to cover the inorganic compound layer 5.

[0172] Either the inorganic compound layer 5 or the coating layer 7 may be omitted. If high barrier properties are not required, both the inorganic compound layer 5 and the coating layer 7 may be omitted.

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

[0174] <5> Fifth embodiment.

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

[0176] The laminate 10E1 shown in Figure 9 is the same as the laminate 10C1 except that the probe drop temperature of the intermediate layer 8 is 180°C or less. It is preferable that the probe drop temperature of the intermediate layer 8 is less than 180°C. It is also preferable that the probe drop temperature of the intermediate layer 8 is 140°C or higher. In the laminate 10E1, it is preferable that the intermediate layer 8 is an unstretched film. Such an intermediate layer 8 increases the strength of the laminate 10E1, particularly its drop strength.

[0177] In this embodiment, an intermediate layer with a probe temperature drop of 180°C or higher may be used. When an intermediate layer with a probe temperature drop within the above range is used, the strength of the laminate, particularly its puncture strength, can be improved. A stretched film is preferred as the intermediate layer with a probe temperature drop of 180°C or higher.

[0178] <5.2> Effects The laminate 10E1 described above has a probe temperature drop within the above range for the base layer 1. Therefore, the laminate 10E1, like the laminate 10A1, has excellent heat resistance.

[0179] Furthermore, the laminate 10E1 includes an intermediate layer 8 whose probe drop temperature is within the above range. This intermediate layer 8 increases the strength of the laminate 10E1, particularly its drop strength. That is, in the laminate 10E1, when used in packaging, the intermediate layer 8 located inside the base layer 1 is softer than the base layer 1. This structure is suitable for absorbing the impact that occurs when a packaged item using the laminate 10E1 as the packaging material is dropped. Therefore, packaged items using the laminate 10E1 as the packaging material are less likely to be damaged (broken) by drops. Consequently, the laminate 10E1 has excellent strength, particularly drop strength.

[0180] Furthermore, the laminate 10E1 has a polyethylene content of 90% by mass or more. Therefore, the laminate 10E1 also has excellent recyclability.

[0181] <5.3> Modified Examples The laminate 10E1 can undergo various deformations. Figure 10 is a schematic cross-sectional view showing a first modified example of the laminate shown in Figure 9. Figure 11 is a schematic cross-sectional view showing a second modified example of the laminate shown in Figure 9.

[0182] Laminate 10E2 shown in Figure 10 and laminate 10E3 shown in Figure 11 are the same as laminate 10E1, except that they further include the inorganic compound layer 5 described in the third embodiment. In laminate 10E2, the inorganic compound layer 5 is interposed between the first adhesive layer 3A and the intermediate layer 8. In laminate 10E3, the inorganic compound layer 5 is interposed between the second adhesive layer 3B and the intermediate layer 8. That is, in laminate 10E2, the inorganic compound layer 5 is provided on one side of the intermediate layer 8, and in 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 also be interposed between the base material layer 1 and the first adhesive layer 3A.

[0183] Laminates 10E2 and 10E3 may include the coating layer described in the second embodiment instead of the inorganic compound layer 5. Laminate 10E2 may further include the coating layer between the inorganic compound layer 5 and the first adhesive layer 3A. 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, can also function as a gas barrier layer.

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

[0185] <6> Sixth Embodiment <6.1> Laminate Figure 12 is a schematic cross-sectional view showing a laminate according to the sixth embodiment of the present invention.

[0186] The laminate 10F1 shown in Figure 12 is the same as the laminate 10E3, except that it further includes a printing 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. The printing layer 4 can be the one described in the first and third embodiments. The protective layer 6 and the coating layer 7 can be the ones described in the second embodiment.

[0187] <6.2> Effects The laminate 10F1 described above has a probe temperature drop of the base layer 1 within the above range. Furthermore, the laminate 10F1 includes a protective layer 6. Therefore, the laminate 10F1 can achieve even better heat resistance, and in particular, better heat sealability. Accordingly, by adopting the above configuration for the laminate 10F1, the temperature range for heat sealing performed for bag making is expanded, and a decrease in productivity becomes less likely.

[0188] Furthermore, the laminate 10F1 includes an intermediate layer 8 in which the probe drop temperature is within the above range. This intermediate layer 8 increases the strength of the laminate 10F1, particularly its drop resistance. Therefore, the laminate 10F1 has excellent strength, especially drop resistance.

[0189] Furthermore, when the haze is low, the substrate layer 1 exhibits excellent transparency. Therefore, in this case, images such as patterns and characters displayed by the printed layer 4 can be viewed with good visibility.

[0190] Furthermore, laminate 10F1 has a polyethylene content of 90% or more by mass. Therefore, laminate 10F1 also has excellent recyclability.

[0191] <6.3> Modified form The laminate 10F1 can undergo various deformations. 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 coating layer 7 is provided so as to cover the inorganic compound layer 5.

[0192] Either the inorganic compound layer 5 or the coating layer 7 may be omitted. If high barrier properties are not required, both the inorganic compound layer 5 and the coating layer 7 may be omitted.

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

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

[0195] The packaged article 100A shown in Figure 13 includes a packaging body 110A and the contents contained therein.

[0196] The packaging 110A is a flat pouch. The packaging 110A includes a pair of main films. Each of the main films is either one of the laminates described in the first to sixth embodiments, or cut from one of them. The main films are overlapped so that their sealant layers face each other, and their periphery is heat-sealed to one another. The packaging 110A is provided with a notch in its heat-sealed portion as an easy-open structure.

[0197] The contents may be liquids, solids, or mixtures thereof. Examples of contents include food or pharmaceuticals.

[0198] <8> Eighth Embodiment Figure 14 is a schematic diagram showing a packaged article according to the eighth embodiment of the present invention.

[0199] The packaged article 100B shown in Figure 14 includes a packaging body 110B and contents contained therein. The contents are, for example, the same as those described for packaged article 100A.

[0200] The packaging 110B is a standing pouch. The packaging 110B includes a pair of body films and a bottom film. Each of these films is either one of the laminates described in the first to sixth embodiments, or cut from one of them.

[0201] The pair of main films are overlapped so that their sealant layers face each other, and their periphery is heat-sealed to each other except for one end and the area near it. The bottom film is folded in half so that it forms a mountain fold when viewed from the sealant layer side, and at the position of the one end, it is sandwiched between the pair of main films so that the mountain fold faces the other end of the main films. The bottom film is heat-sealed to the pair of main films except for its central part. In addition, the outer surfaces of the bottom film are bonded together at the bottom sides of the packaging 110B.

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

[0203] <9> Ninth Embodiment Figure 15 is a schematic diagram showing a packaged article according to the ninth embodiment of the present invention.

[0204] The packaged article 100C shown in Figure 15 includes a packaging body 110C and contents contained therein. The contents are, for example, the same as those described for packaged article 100A.

[0205] The packaging 110C is a gusseted pouch. The packaging 110C includes a container body 110C1, a mouthpiece 110C2, and a lid 110C3.

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

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

[0208] Each of the side films is folded in half so that it forms a mountain fold when viewed from the sealant layer side. These side films are sandwiched between the pair of main films on both sides, with the mountain folds facing each other. A portion of the peripheral edge of each side film is heat-sealed to one side of the main film, and the remaining portion of the peripheral edge is heat-sealed to the other side of the main film. In addition, the outer surfaces of each side film are bonded together at the upper and lower positions of the packaging 110C, respectively. The container body 110C1 may also include a bottom film.

[0209] As described above, the mouth member 110C2 is sandwiched between the main body film and includes a heat-sealed portion. The mouth member 110C2 further includes a mouth portion that protrudes outward from the container body 110C1. The mouth portion has a substantially cylindrical shape and is provided with male threads on the outer surface of its side wall. The lid 110C3 has a bottomed cylindrical shape. The lid 110C3 is provided with female threads on the inner surface of its side wall and is screwed into the mouth portion of the mouth member 110C2. [Examples]

[0210] The results of tests conducted in connection with the present invention are described below.

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

[0212] Next, one side of the substrate layer was subjected to corona treatment. Subsequently, silicon dioxide (SiO₂) was deposited as an inorganic compound layer onto the corona-treated side of the substrate layer using an electron beam heating vacuum deposition apparatus. x A vapor-deposited film was formed to a thickness of 40 nm. Then, a pattern was printed onto the inorganic compound layer using gravure ink to form a printed layer.

[0213] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the printed surface of the substrate layer. Then, a sealant layer, a linear low-density polyethylene resin (LLDPE) film (60 μm thick), was laminated to the substrate layer via this adhesive layer. The laminate was created in the manner described above.

[0214] (1.1.2) Example 2A The laminate 10A1 shown in Figure 1 was manufactured using the same method as in Example 1A, except that an inorganic compound layer was not provided.

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

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

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

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

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

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

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

[0222] (1.1.10) Example 10A The laminate 10A1 shown in Figure 1 was manufactured in the same manner as in Example 2A, except that a polyamine-based gas barrier adhesive was used instead of a dry laminating adhesive (urethane-based adhesive) as the adhesive.

[0223] (1.1.11) Example 11A The laminate 10A1 shown in Figure 1 was manufactured using the same method as in Example 2A, except that a urethane-based gas barrier adhesive was used instead of a dry laminating adhesive (urethane-based adhesive) as the adhesive.

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

[0225] (1.1.14) Comparative example 3A The laminate was manufactured in the same manner as in Example 1A, except that a polyethylene film with a thickness of 25 μm and a probe drop temperature of 164°C was used as the base layer, instead of a polyethylene film with 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 manufacture of the above-mentioned laminate was subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction pattern obtained from these measurements was then examined to determine whether it had sharp diffraction peaks corresponding to the (110) plane.

[0227] Furthermore, the sealing properties, heat resistance, print visibility, and gas barrier properties of the above-mentioned laminate were evaluated. The method for measuring the probe drop temperature and the evaluation methods for sealing properties, heat resistance, print visibility, and gas barrier properties are described below.

[0228] (1.2.1) Method for measuring probe drop temperature The probe temperature drop was measured using the following method. An MPF-3D-SA (product name) manufactured by Oxford Instruments Ltd. was used as the atomic force microscope. A Ztherm (product name) manufactured by Oxford Instruments Ltd. was attached to it as the nanothermal microscope. An AN2-200 (product name) manufactured by Anasis Instruments was used as the cantilever (probe).

[0229] For the measurement, first, the shape of the sample was measured in AC mode over a 10 μm square field of view. Next, the cantilever (probe) was moved 5 to 10 μm away from the sample in the Z direction. In this state, the instrument's Detrend correction function was activated in contact mode with a maximum applied voltage of 6 V and a heating rate of 0.5 V / s to correct for the change in cantilever deflection due to voltage application. Then, in contact mode, the cantilever was brought into contact with the sample so that the change in deflection before and after contact between the cantilever and the sample was 0.2 V. While maintaining a constant deflection value, the sample was heated by applying voltage to the cantilever at a maximum applied voltage of 6 V and a heating rate of 0.5 V / s. The Z displacement at this time was recorded, and the measurement was stopped when the Z displacement changed from rising to falling and dropped 50 nm from the point of change. If the Z displacement reached the maximum applied voltage without decreasing by 50 nm from the point of change, the maximum applied voltage during detrend correction and measurement was increased by 0.5 V, and the same procedure as above was repeated. The applied voltage at which the recorded Z displacement was maximum was converted to temperature by referring to the calibration curve described later. This measurement was performed at 10 points within a 10 μm square field of view, and the average value of the obtained temperatures was taken as the probe drop temperature.

[0230] To obtain a calibration curve that converts 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 measured as the melting peak temperatures using a differential scanning calorimeter (DSC) at a heating rate of 5°C / min.

[0231] The same measurements as described above were performed on each of these calibration samples. The maximum applied voltage during Detrend correction and measurement was set to 3.5V for polycaprolactone, 5.5V for low-density polyethylene, 6.5V for polypropylene, and 7.8V for polyethylene terephthalate.

[0232] Then, a calibration curve was created by approximating the relationship between the applied voltage at which the Z displacement was maximized during measurements on the calibration sample and the melting point of the constituent sample using a cubic function based on the least squares method.

[0233] (1.2.2) Method for evaluating sealing performance Samples cut from the laminate into 10 cm squares were folded in half with the sealant layer facing inward and heat-sealed using a heat seal tester. Specifically, the bottom sealing temperature was first set to 100°C and the top sealing temperature to 120°C, and a pressure of 0.1 MPa was applied for 1 second. Then, the presence or absence of melting of the sealing surface was checked, and the area on the top surface of the folded sample where the heat seal bar was applied was observed. If neither the sealing surface nor the top surface of the sample melted, the top sealing temperature was increased by 10°C increments while keeping the bottom sealing temperature at 100°C, and the same pressurization and observation were performed until at least one of the sealing surface and the top surface of the sample melted. The sealing performance was then evaluated according to the following criteria. A: There was no melting on the top surface of the sample, and there were no problems in terms of appearance. B: The top surface of the sample was melted, which presented a visual problem.

[0234] (1.2.3) Method for evaluating print legibility The pattern displayed by the printed layer was visually observed from the substrate layer side, and its visibility was evaluated according to the following criteria. A: We were able to clearly see the pattern displayed by the printed layer. B: The pattern displayed by the printed layer was blurry and unclear.

[0235] (1.2.4) Method for evaluating gas barrier properties The laminate was boiled, and then the oxygen transmission rate (OTR) was measured at 30°C and 70% relative humidity. An oxygen permeability analyzer (MOCON OXTRAN-2 / 20) was used for this measurement. The gas barrier properties were then evaluated based on the oxygen transmission rate according to the following criteria. A: OTR is 10cc / m 2 It was less than ・day·atm. B:OTR is 10cc / m 2 It was more than 1 day ATM.

[0236] (1.2.5) Method for evaluating heat resistance A sample made by cutting the laminate into a 10 cm square was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was set to 30°C and the top sealing temperature to 170°C, and a pressure of 0.2 MPa was applied to the folded sample for 1 second. Then, the presence or absence of melting of the sealed surface was checked, and the area of ​​the top surface of the folded sample to which the heat seal bar was applied was observed to see if it was adhering to the heat seal bar, and the heat resistance was evaluated according to the following criteria. A: The top surface of the sample did not adhere to the heat sealing bar. B: The top surface of the sample adhered to the heat sealing bar.

[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 Table 1A and Table 1B, all of the laminates with the probe descent temperature of the base material layer of 180°C or higher had good sealing properties, heat resistance, and print visibility. On the other hand, all of the laminates with the probe descent temperature of the base material layer of less than 180°C had insufficient sealing properties, heat resistance, and visibility.

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

[0242] Next, one surface of the base material layer was subjected to corona treatment. Subsequently, polyamideimide resin was applied to the corona-treated surface of the base material layer to form a protective layer with a thickness of 0.5 μm. The non-volatile content concentration in the coating liquid used for forming the protective layer was 5% by mass.

[0243] Next, the other surface of the base material layer was subjected to corona treatment. Then, using a vacuum evaporation apparatus of an electron beam heating type, a silicon oxide (SiO x ) evaporation film was formed as an inorganic compound layer to a thickness of 40 nm. Subsequently, 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 with a thickness of 0.3 μm. Thereafter, a pattern was printed on the inorganic compound layer using gravure ink to form a printed layer.

[0244] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the printed surface of the substrate layer. Then, a sealant layer, a linear low-density polyethylene resin (LLDPE) film (60 μm thick), was laminated to the substrate layer via this adhesive layer. The laminate was created in the manner described above.

[0245] (2.1.2) Example 2B The laminate 10B2 shown in Figure 4 was manufactured using the same method as in Example 1B, except that the thickness of the protective layer was 1 μm.

[0246] (2.1.3) Example 3B The laminate was manufactured using the same method as in Example 1B, except that a protective layer was not provided.

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

[0248] (2.1.5) Example 5B The laminate 10B2 shown in Figure 4 was manufactured in the same manner as in Example 1B, except that instead of forming a protective layer with a thickness of 0.5 μm by coating it with polyamide-imide resin, a protective layer with a thickness of 0.5 μm made of urethane resin was formed.

[0249] (2.1.6) Example 6B The laminate 10B2 shown in Figure 4 was manufactured in the same manner as in Example 1B, except that instead of forming a 0.5 μm thick protective layer by coating it with polyamide-imide resin, a 1 μm thick protective layer made of urethane resin was formed.

[0250] (2.1.7) Example 7B The laminate 10B2 shown in Figure 4 was manufactured in the same manner as in Example 1B, except that instead of forming a 0.5 μm thick protective layer by coating it with polyamide-imide resin, a 1 μm thick protective layer made of ethylene-vinyl alcohol copolymer (EVOH) was formed.

[0251] (2.1.8) Example 8B The laminate 10B2 shown in Figure 4 was manufactured in the same manner as in Example 1B, except that instead of forming a 0.5 μm thick protective layer by coating it with polyamide-imide resin, a 1 μm thick protective layer made of acrylic resin was formed.

[0252] (2.1.9) Comparative example 1B The laminate was manufactured in the same manner as in Example 1B, except that a polyethylene film with a thickness of 25 μm and a probe drop temperature of 152°C was used as the base layer instead of a polyethylene film with a thickness of 25 μm and a probe drop temperature of 211°C, without providing a protective layer.

[0253] (2.2) Measurement and evaluation methods The substrate layer used in the manufacture of the above-mentioned laminate was subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction pattern obtained from these measurements was then examined to determine whether it had sharp diffraction peaks corresponding to the (110) plane.

[0254] Furthermore, the sealing properties, heat resistance, and print visibility of the above-mentioned laminate were evaluated. The method for measuring the probe drop temperature and the evaluation methods for sealing properties, heat resistance, and print visibility are described below.

[0255] (2.2.1) Method for measuring probe drop temperature The probe temperature drop was measured using the method described in (1.2.1).

[0256] (2.2.2) Method for evaluating sealing performance A sample obtained by cutting out the laminate into a 10 cm square was folded in half with the sealant layer on the inside, and heat-sealed using a heat-sealing tester. Specifically, first, the lower surface sealing temperature was set to 100 °C, the upper surface sealing 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 upper surface of the folded sample where the heat-sealing bar was applied was observed. When no melting or appearance defect occurred on the upper surface of the sample, with the lower surface sealing temperature fixed at 100 °C, the upper surface sealing temperature was increased by 10 °C each time until melting or appearance defect occurred on the upper surface of the sample, and the same pressurization and observation as above were performed. Then, the sealing performance was evaluated according to the following criteria.

[0257] A: When the seal surface melted, no melting or appearance defect occurred on the upper surface of the sample. B: Before or when the seal surface melted, melting or appearance defect occurred on the upper surface of the sample.

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

[0259] (2.2.4) Method for evaluating heat resistance A sample obtained by cutting out the laminate into a 10 cm square was folded in half with the sealant layer on the inside. Next, the lower surface sealing temperature of the heat-sealing tester was set to 30 °C, the upper surface sealing 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 it was observed whether the area of the upper surface of the folded sample where the heat-sealing bar was applied adhered to the heat-sealing 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-sealing bar. B: The upper surface of the sample adhered to the heat-sealing bar. Also, for the laminate having a protective layer, the heat resistance was further evaluated in the same manner as above, except that the upper surface sealing 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, laminates with a probe drop temperature of 180°C or higher in the base layer all exhibited good heat resistance and print visibility. Furthermore, laminates with a probe drop temperature of 180°C or higher in the base layer and a protective layer also showed excellent sealing performance. In contrast, laminates with a probe drop temperature of less than 180°C in the base layer and without a protective layer exhibited insufficient sealing performance, heat resistance, and visibility.

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

[0264] First, a polyethylene film with a thickness of 25 μm and corona treatment applied to one side was prepared as the base layer. This polyethylene film has a density of 0.950 g / cm³. 3 The probe temperature drop was 211°C. As will be described later, in this example and the examples and comparative examples described below, the probe temperature drop was measured by the method described in (1.2.1). A printed layer was formed by printing a pattern on the corona-treated surface of this substrate layer using gravure ink.

[0265] Furthermore, a polyethylene film with a thickness of 25 μm and corona treatment on one side was prepared as an intermediate layer. This polyethylene film has a density of 0.950 g / cm³. 3 The probe drop temperature was 211°C. On the corona-treated surface of this intermediate layer, silicon dioxide (SiO₂) was deposited as an inorganic compound layer using an electron beam heating vacuum deposition apparatus. xA vapor-deposited film was formed to a thickness of 10 nm.

[0266] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the back surface of the substrate layer where the printed layer was formed and the back surface of the intermediate layer where the inorganic compound layer was formed. The coating was then dried to form first and second adhesive layers, each with a thickness of 3 μm. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between, so that the printed layer and the inorganic compound layer faced each other. At the same time, the intermediate layer was bonded to a linear low-density polyethylene resin (LLDPE) film (60 μm thick), which served as a sealant layer, via the second adhesive layer. The laminate was created in the manner described above.

[0267] (3.1.2) Example 2C The laminate 10C1 shown in Figure 5 was manufactured in the same manner as in Example 1C, except that an inorganic compound layer was not provided. In this example as well, a printing layer was provided between the substrate layer 1 and the first adhesive layer 3A, similar to Example 1C.

[0268] (3.1.3) Example 3C The laminate 10C2 shown in Figure 6 was manufactured in the same manner as in Example 1C, except that a polyamine-based gas barrier adhesive was used instead of a dry laminating adhesive (urethane-based adhesive) as the adhesive. In this example as well, a printing layer was provided between the substrate layer 1 and the first adhesive layer 3A, similar to Example 1C.

[0269] (3.1.4) Example 4C Laminate 10C2 shown in Figure 6 was manufactured in the same manner as in Example 1C, except that the polyethylene film used as the base layer was the following polyethylene film instead of the polyethylene film with a probe drop temperature of 211°C mentioned above. Specifically, in this example, the base layer had a thickness of 25 μm and a density of 0.950 g / cm³. 3 The probe drop temperature was 205°C, and a polyethylene film with corona treatment applied to one side was used. In this example as well, a printing layer was provided between the base layer 1 and the first adhesive layer 3A, similar to Example 1C.

[0270] (3.1.5) Example 5C The laminate 10C2 shown in Figure 6 was manufactured in the same manner as in Example 1C, except for the following: In this example, instead of using the polyethylene film with a probe drop temperature of 211°C as the base layer, a material with a thickness of 25 μm and a density of 0.950 g / cm³ was used. 3 The polyethylene film used had a probe drop temperature of 203°C and one side was corona-treated. In this example, instead of using the above polyethylene film with a probe drop temperature of 211°C as the intermediate layer, a film with a thickness of 25 μm and a density of 0.950 g / cm³ was used. 3 The probe drop temperature was 205°C, and a polyethylene film with corona treatment applied to one side was used. In this example as well, a printing layer was provided between the base layer 1 and the first adhesive layer 3A, similar to Example 1C.

[0271] (3.1.6) Example 6C The laminate 10E2 shown in Figure 10 was manufactured in the same manner as in Example 1C, except for the following: In this example, instead of using the polyethylene film with a probe drop temperature of 211°C as the intermediate layer, a film with a thickness of 40 μm and a density of 0.949 g / cm³ was used. 3 The probe drop temperature was 156°C, and a polyethylene film with corona treatment applied to one side was used. In this example as well, a printing layer was provided between the base layer 1 and the first adhesive layer 3A, similar to 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 film with a thickness of 40 μm and a density of 0.949 g / cm³ is used. 3 The laminate was manufactured in the same manner as in Example 1C, except that the probe drop temperature was 156°C and a polyethylene film with corona treatment applied to one side was used.

[0273] (3.1.8) Comparative Example 2C The laminate was manufactured in the same manner as in Example 1C, except for the following: In this example, instead of using the polyethylene film with a probe drop temperature of 211°C as the base layer, a film with a thickness of 40 μm and a density of 0.949 g / cm³ was used. 3 The polyethylene film used had a probe drop temperature of 156°C and one side was corona-treated. In this example, instead of using the above polyethylene film with a probe drop temperature of 211°C as the intermediate layer, a film with a thickness of 40 μm and a density of 0.949 g / cm³ was used. 3 The probe drop temperature was 156°C, and a polyethylene film with corona treatment applied to one side was used.

[0274] (3.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0275] Furthermore, the sealing properties, heat resistance, print visibility, and gas barrier properties of the above-mentioned laminate were evaluated. In addition, the puncture strength of the above-mentioned laminate was measured. The methods for measuring the probe drop temperature and puncture strength, and the evaluation methods for sealing properties, heat resistance, print visibility, and gas barrier properties are described below.

[0276] (3.2.1) Method for measuring probe drop temperature The probe temperature drop was measured using the method described in (1.2.1).

[0277] (3.2.2) Method for evaluating sealing performance Samples, each cut from a laminate into a 10 cm square, were folded in half with the sealant layer facing inward and heat-sealed using a heat seal tester. Specifically, a temperature of 140°C and a pressure of 0.1 MPa were applied to the folded sample for 1 second. The area of ​​the sample surface where the heat seal bar was applied was then observed, and the sealing performance was evaluated according to the following criteria. A: There was no melting on the sample surface, and there were no problems with its appearance. B: The surface of the sample was melted, which presented a visual problem.

[0278] (3.2.3) Evaluation method for print legibility Print legibility was evaluated using the method described in (1.2.3).

[0279] (3.2.4) Method for evaluating gas barrier properties The gas barrier properties were evaluated using the method described in (1.2.4).

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

[0281] (3.2.6) Method for evaluating heat resistance Heat resistance was evaluated using the method described 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, laminates with a probe drop temperature of 180°C or higher in the base layer all exhibited good sealing properties, heat resistance, and print visibility. Furthermore, laminates with probe drop temperatures of 180°C or higher in both the base layer and the intermediate layer all showed high puncture strength. In contrast, laminates with a probe drop temperature of less than 180°C in the base layer all exhibited insufficient sealing properties, heat resistance, and visibility. Furthermore, laminates with probe drop temperatures of less than 180°C in both the base layer and the intermediate layer all showed low puncture strength.

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

[0286] Next, one side of the substrate layer was subjected to corona treatment. Subsequently, a polyamide-imide resin was applied to the corona-treated side of the substrate layer to form a protective layer with a thickness of 0.5 μm. The non-volatile content concentration of the coating solution used to form the protective layer was 5% by mass.

[0287] Next, the other side of the substrate layer was subjected to corona treatment. Then, a pattern was printed onto the corona-treated side of the substrate layer using gravure ink to form a printed layer on the inorganic compound layer.

[0288] Furthermore, a polyethylene film with a thickness of 25 μm and a probe drop temperature of 211°C was prepared as an intermediate layer. Next, one side of the intermediate layer was subjected to corona treatment. On this corona-treated side of the intermediate layer, silicon dioxide (SiO₂) was deposited as an inorganic compound layer using an electron beam heating type vacuum deposition apparatus. x A vapor-deposited film was formed to a thickness of 40 nm. Subsequently, a coating solution for forming a coating layer was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm.

[0289] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the printed surface of the substrate layer and the surface of the coating layer, and the coating film was dried to form the first and second adhesive layers. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between so that the printed layer and the intermediate layer faced each other, and the intermediate layer and the sealant layer were bonded together with the second adhesive layer so that the coating layer and the sealant layer, which is a linear low-density polyethylene resin (LLDPE) film (60 μm thick), faced each other. The laminate was created in the manner described above.

[0290] (4.1.2) Example 2D The laminate 10D1 shown in Figure 8 was manufactured using the same method as in Example 1D, except that the thickness of the protective layer was 1 μm.

[0291] (4.1.3) Example 3D The laminate 10D1 shown in Figure 8 was manufactured using the same method as in Example 1D, except that the thickness of the protective layer was 3 μm.

[0292] (4.1.4) Example 4D The laminate was manufactured in the same manner as in Example 1D, except that a protective layer was not provided, and instead of using a polyethylene film with a thickness of 25 μm and a probe drop temperature of 211°C as the intermediate layer, a polyethylene film with a thickness of 25 μm and a probe drop temperature of 160°C was used.

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

[0294] (4.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0295] Furthermore, the sealability, heat resistance, print visibility, and recyclability of the above-mentioned laminate were evaluated. In addition, the puncture strength of the above-mentioned laminate was measured. The methods for measuring probe drop temperature and puncture strength, and the evaluation methods for sealability, heat resistance, print visibility, and recyclability are described below.

[0296] (4.2.1) Method for measuring probe drop temperature The probe temperature drop was measured using the method described in (1.2.1).

[0297] (4.2.2) Method for evaluating sealing performance Samples cut from the laminate into 10 cm squares were folded in half with the sealant layer facing inward and heat-sealed using a heat seal tester. Specifically, the bottom sealing temperature was first set to 100°C, and the top sealing temperature to 120°C, and a pressure of 0.1 MPa was applied for 1 second. Then, the presence or absence of melting of the sealed surface was checked, and the area on the top surface of the folded sample where the heat seal bar was applied was observed. If no melting or defects in appearance occurred on the top surface of the sample, the top sealing temperature was increased by 10°C increments while keeping the bottom sealing temperature fixed at 100°C, and the same pressurization and observation were performed until melting or defects occurred on the top surface of the sample. The temperature at which melting or defects occurred on the top surface of the sample was recorded. Furthermore, the sealability was evaluated according to the following criteria.

[0298] A: No melting or cosmetic defects occurred on the upper surface of the sample during the melting of the sealing surface. B: Melting or defects in appearance occurred on the upper surface of the sample during or before the melting of the sealing surface.

[0299] (4.2.3) Evaluation method for print legibility Print legibility was evaluated using the method described in (1.2.3).

[0300] (4.2.4) Method for evaluating recyclability The proportion of polyethylene in the total amount of resin contained in the laminate was calculated. This proportion was then used to evaluate the recyclability, referring to the following criteria. A: The proportion of polyethylene was 90% by mass or more. B: The proportion of polyethylene was less than 90% by mass.

[0301] (4.2.5) Method for measuring puncture strength Puncture strength was measured by the method described in (3.2.5).

[0302] (4.2.6) Method for evaluating heat resistance Heat resistance was evaluated using 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, laminates with a probe drop temperature of 180°C or higher in the base layer all exhibited good heat resistance and print visibility. Furthermore, laminates with a probe drop temperature of 180°C or higher in the base layer and a protective layer also exhibited excellent sealing properties. In addition, laminates with a probe drop temperature of 180°C or higher in both the base layer and the intermediate layer and a protective layer all showed high puncture strength. In contrast, laminates with a probe drop temperature of less than 180°C in the base layer all exhibited insufficient heat resistance and visibility. Furthermore, laminates with a probe drop temperature of less than 180°C in both the base layer and the intermediate layer showed low puncture strength.

[0306] (5) Exam E (5.1) Manufacturing of laminates (5.1.1) Example 1E The laminate 10E2 shown in Figure 10 was manufactured by the following method. In this example, a printing layer was provided between the base material layer 1 and the first adhesive layer 3A.

[0307] First, a polyethylene film with a thickness of 25 μm and corona treatment applied to one side was prepared as the base layer. This polyethylene film has a density of 0.950 g / cm³. 3 The probe temperature drop was 211°C. As will be described later, in this example and the examples and comparative examples described below, the probe temperature drop was measured by the method described in (1.2.1). A printed layer was formed by printing a pattern on the corona-treated surface of this substrate layer using gravure ink.

[0308] Furthermore, a polyethylene film with a thickness of 40 μm and corona treatment on one side was prepared as an intermediate layer. This polyethylene film had a density of 0.949 g / cm³. 3 The probe drop temperature was 156°C. On the corona-treated surface of this intermediate layer, silicon dioxide (SiO₂) was deposited as an inorganic compound layer using an electron beam heating vacuum deposition apparatus. x A vapor-deposited film was formed to a thickness of 10 nm.

[0309] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the back surface of the substrate layer where the printed layer was formed and the back surface of the intermediate layer where the inorganic compound layer was formed. The coating was then dried to form first and second adhesive layers, each with a thickness of 3 μm. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between, so that the printed layer and the inorganic compound layer faced each other. At the same time, the intermediate layer was bonded to a linear low-density polyethylene resin (LLDPE) film (60 μm thick), which served as a sealant layer, via the second adhesive layer. The laminate was created in the manner described above.

[0310] (5.1.2) Example 2E The laminate 10E1 shown in Figure 9 was manufactured in the same manner as in Example 1EC, except that an inorganic compound layer was not provided. In this example as well, a printing layer was provided between the substrate layer 1 and the first adhesive layer 3A, similar to Example 1E.

[0311] (5.1.3) Example 3E The laminate 10E2 shown in Figure 10 was manufactured in the same manner as in Example 1E, except that a polyamine-based gas barrier adhesive was used instead of a dry laminating adhesive (urethane-based adhesive) as the adhesive. In this example as well, a printing layer was provided between the substrate layer 1 and the first adhesive layer 3A, similar to Example 1E.

[0312] (5.1.4) Example 4E The laminate 10E2 shown in Figure 10 was manufactured in the same manner as in Example 1E, except for the following: In this example, instead of using the polyethylene film with a probe drop temperature of 211°C as the base layer, a material with a thickness of 25 μm and a density of 0.950 g / cm³ was used. 3 The polyethylene film used had a probe drop temperature of 205°C and one side was corona-treated. In this example, instead of using the above polyethylene film with a probe drop temperature of 156°C as the intermediate layer, a film with a thickness of 25 μm and a density of 0.950 g / cm³ was used. 3 The probe drop temperature was 160°C, and a polyethylene film with corona treatment applied to one side was used. In this example as well, a printing layer was provided between the base layer 1 and the first adhesive layer 3A, similar to Example 1E.

[0313] (5.1.5) Example 5E The laminate 10E2 shown in Figure 10 was manufactured in the same manner as in Example 1E, except that the polyethylene film used as the base layer was the following polyethylene film instead of the polyethylene film with a probe drop temperature of 211°C mentioned above. Specifically, in this example, the base layer had a thickness of 25 μm and a density of 0.950 g / cm³. 3The probe drop temperature was 203°C, and a polyethylene film with corona treatment applied to one side was used. In this example as well, a printing layer was provided between the base layer 1 and the first adhesive layer 3A, similar to Example 1E.

[0314] (5.1.6) Example 6E The laminate 10C2 shown in Figure 6 was manufactured in the same manner as in Example 1E, except for the following: In this example, instead of using the polyethylene film with a probe drop temperature of 156°C as the intermediate layer, a film with a thickness of 25 μm and a density of 0.950 g / cm³ was used. 3 The probe drop temperature was 211°C, and a polyethylene film with corona treatment applied to one side was used. In this example as well, a printing layer was provided between the base layer 1 and the first adhesive layer 3A, similar to 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 film with a thickness of 40 μm and a density of 0.949 g / cm³ is used. 3 The laminate was manufactured in the same manner as in Example 1E, except that the probe drop temperature was 156°C and a polyethylene film with corona treatment applied to one side was used.

[0316] (5.1.8) Comparative Example 2E The laminate was manufactured in the same manner as in Example 1E, except for the following: In this example, instead of using the polyethylene film with a probe drop temperature of 211°C as the base layer, a film with a thickness of 40 μm and a density of 0.949 g / cm³ was used. 3 The polyethylene film used had a probe drop temperature of 156°C and one side was corona-treated. In this example, instead of using the above polyethylene film with a probe drop temperature of 156°C as the intermediate layer, a film with a thickness of 25 μm and a density of 0.950 g / cm³ was used. 3 The probe drop temperature was 205°C, and a polyethylene film with corona treatment applied to one side was used.

[0317] (5.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0318] Furthermore, the sealing properties, heat resistance, print visibility, and gas barrier properties of the above-mentioned laminate were evaluated. Drop strength measurements were also performed on the above-mentioned laminate. The methods for measuring probe drop temperature and drop strength, and the evaluation methods for sealing properties, heat resistance, print visibility, and gas barrier properties are described below.

[0319] (5.2.1) Method for measuring probe drop temperature The probe temperature drop was measured using the method described in (1.2.1).

[0320] (5.2.2) Method for evaluating sealing performance The sealing performance was evaluated using the method described in (3.2.2).

[0321] (5.2.3) Evaluation method for print legibility Print legibility was evaluated using the method described in (1.2.3).

[0322] (5.2.4) Method for evaluating gas barrier properties The gas barrier properties were evaluated using the method described in (1.2.4).

[0323] (5.2.5) Method for measuring drop strength Ten bags were made by cutting the laminate to a predetermined size and heat-sealing the edges. Each bag had an opening for inserting contents. The dimensions of the bags were 100 mm x 150 mm. Next, 200 mL of tap water was filled into each bag, and the opening was heat-sealed to obtain packaged items. Then, each packaged item was stored at 5°C for one day, and then dropped 50 times from a height of 1.5 m. The ratio of the number of packaged items whose bags broke within 50 drops to the total number of packaged items (10) was calculated as the drop strength.

[0324] (5.2.6) Method for evaluating heat resistance Heat resistance was evaluated using the method described 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, laminates with a probe drop temperature of 180°C or higher in the base layer all exhibited good sealing properties, heat resistance, and print visibility. Furthermore, laminates with a probe drop temperature of 180°C or higher in the base layer and less than 180°C in the intermediate layer exhibited excellent drop strength. In contrast, laminates with a probe drop temperature of less than 180°C in the base layer all exhibited insufficient sealing properties, heat resistance, and visibility. Laminates with a probe drop temperature of 180°C or higher in the intermediate layer also showed low drop strength.

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

[0329] Next, one side of the substrate layer was subjected to corona treatment. Subsequently, a polyamide-imide resin was applied to the corona-treated side of the substrate layer to form a protective layer with a thickness of 0.5 μm. The non-volatile content concentration of the coating solution used to form the protective layer was 5% by mass.

[0330] Next, the other side of the substrate layer was subjected to corona treatment. Then, a pattern was printed onto the corona-treated side of the substrate layer using gravure ink to form a printed layer on the inorganic compound layer.

[0331] Furthermore, a polyethylene film with a thickness of 25 μm and a probe drop temperature of 160°C was prepared as an intermediate layer. Next, one side of the intermediate layer was subjected to corona treatment. On this corona-treated side of the intermediate layer, silicon dioxide (SiO₂) was deposited as an inorganic compound layer using an electron beam heating type vacuum deposition apparatus. x A vapor-deposited film was formed to a thickness of 40 nm. Subsequently, a coating solution for forming a coating layer was applied to the inorganic compound layer to form a coating layer consisting of an organic-inorganic mixture with a thickness of 0.3 μm.

[0332] Next, a dry laminating adhesive (urethane-based adhesive) was applied to the printed surface of the substrate layer and the surface of the coating layer, and the coating film was dried to form the first and second adhesive layers. The substrate layer and the intermediate layer were then bonded together with the first adhesive layer in between so that the printed layer and the intermediate layer faced each other, and the intermediate layer and the sealant layer were bonded together with the second adhesive layer so that the coating layer and the sealant layer, which is a linear low-density polyethylene resin (LLDPE) film (60 μm thick), faced each other. The laminate was created in the manner described above.

[0333] (6.1.2) Example 2F The laminate 10F1 shown in Figure 12 was manufactured using the same method as in Example 1F, except that the thickness of the protective layer was 1 μm.

[0334] (6.1.3) Example 3F The laminate 10F1 shown in Figure 12 was manufactured using the same method as in Example 1F, except that the thickness of the protective layer was 3 μm.

[0335] (6.1.4) Example 4F The laminate was manufactured in the same manner as in Example 1F, except that a polyethylene film with a thickness of 25 μm and a probe drop temperature of 211°C was used as the intermediate layer instead of a polyethylene film with a thickness of 25 μm and a probe drop temperature of 160°C, without providing a protective layer.

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

[0337] (6.2) Measurement and evaluation methods The substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate were subjected to in-plane measurements using the wide-angle X-ray diffraction method described above. The diffraction patterns obtained from these measurements were then examined to determine whether they possessed sharp diffraction peaks corresponding to the (110) plane.

[0338] Furthermore, the sealability, heat resistance, print visibility, and recyclability of the above-mentioned laminate were evaluated. Drop strength measurements were also performed on the above-mentioned laminate. The methods for measuring probe drop temperature and drop strength, and the evaluation methods for sealability, heat resistance, print visibility, and recyclability are described below.

[0339] (6.2.1) Method for measuring probe drop temperature The probe temperature drop was measured using the method described in (1.2.1).

[0340] (6.2.2) Method for evaluating sealing performance The sealing performance was evaluated using the method described in (4.2.2).

[0341] (6.2.3) Evaluation method for print legibility Print legibility was evaluated using the method described in (1.2.3).

[0342] (6.2.4) Method for evaluating recyclability Recyclability was evaluated using the method described in (4.2.4).

[0343] (6.2.5) Method for measuring drop strength The drop strength was measured using the method described in (5.2.5).

[0344] (6.2.6) Method for evaluating heat resistance Heat resistance was evaluated using 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, laminates with a probe drop temperature of 180°C or higher in the base layer all exhibited good heat resistance and print visibility. Furthermore, laminates with a probe drop temperature of 180°C or higher in the base layer and a protective layer also exhibited excellent sealing properties. In addition, laminates with a probe drop temperature of 180°C or higher in the base layer and a probe drop temperature of less than 180°C in the intermediate layer exhibited excellent drop strength. Conversely, laminates with a probe drop temperature of less than 180°C in the base layer all exhibited insufficient sealing properties, heat resistance, and visibility. Laminates with a probe drop temperature of 180°C or higher in the intermediate layer also showed low drop strength. [Explanation of Symbols]

[0348] 1...Base layer, 2...Sealant layer, 3...Adhesive layer, 3A...First adhesive layer, 3B...Second adhesive layer, 4...Printing 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...Packaging article, 100B...Packaging article, 100C...Packaging article, 110A...Packaging body, 110B...Packaging body, 110C...Packaging body, 110C1...Container body, 110C2...Opening member, 110C3...Lid.

Claims

1. The substrate layer, adhesive layer, and sealant layer are provided in this order. The base layer and the sealant layer contain polyethylene. The substrate layer has a probe drop temperature of 180°C or higher. The probe drop temperature is a laminate obtained by contacting the sample with the cantilever in contact mode such that the change in Deflection before and after contact between the cantilever and the sample is 0.2V, heating the sample by applying voltage to the cantilever under the conditions of a maximum applied voltage of 6V and a heating rate of 0.5V / s while maintaining the Deflection at a constant value, recording the Z displacement at this time, stopping the measurement when the Z displacement changes from rising to falling and drops 50 nm from the change point, and if the Z displacement reaches the maximum applied voltage without dropping 50 nm from the change point, increasing the maximum applied voltage during Detrend correction and measurement by 0.5V, repeating the same operation as above, and converting the applied voltage at which the recorded Z displacement is maximum into temperature.

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

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

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. 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 the outermost layer facing the sealant layer with the base material layer in between.

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 base layer is a biaxially oriented film.

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

12. The laminate according to claim 1, further comprising a gas barrier layer 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 according to claim 1, wherein the sealant layer is white.

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

16. A packaging body comprising the laminate according to any one of claims 1 to 15.

17. The packaging according to claim 16, which is a standing pouch.

18. The packaging according to claim 16, and the contents contained therein Packaged articles containing the following:

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