Laminated bodies, packaging bodies and packaged articles

Abstract

This invention provides a laminate containing polyethylene and having excellent recyclability, heat resistance, or strength, as well as a packaging body and packaged articles containing the laminate. The laminate (10A1) sequentially comprises a substrate layer (1), an adhesive layer (3), and a sealant layer (2). The substrate layer (1) and the sealant layer (2) contain polyethylene. The crystallinity of the substrate layer (1), measured by the parallel beam method of X-ray diffraction in a diffraction angle range of 10° to 30°, is 35% or more, which is the ratio of the crystallized peak area to the total peak area.

Description

Technical Field

[0001] This invention relates to laminates, packaging bodies, and packaged articles. Background Technology

[0002] Packaging materials used in packaging bags and the like require a wide variety of properties depending on their intended use. Examples of required properties include heat resistance, transparency, heat-sealing properties, strength, gas barrier properties, puncture resistance, visibility, bag-making suitability, printability, and transportability. In order to fully satisfy such a wide range of performance requirements, it has been common practice to combine multiple synthetic resin films with different properties for use (see, for example, Patent Document 1).

[0003] In recent years, with the growing calls for building a circular society, there is a growing need for packaging materials with high recyclability. It is generally believed that packaging materials with a resin content of 90% or more by mass have high recyclability. However, as mentioned above, existing packaging materials are composed of dissimilar resin materials, making it difficult to separate the individual resins after use, thus hindering individual recycling. Therefore, even with intensive recycling efforts, packaging made from existing materials can only be recovered through incineration, which contradicts the current environmental protection perspective.

[0004] From the perspective of recyclability, technologies have been proposed for manufacturing packaging materials with high polyethylene content or for making packaging films with the simplest possible layer composition (see, for example, Patent Documents 2 and 3). However, from the perspective of strength or heat resistance, there are problems such as limiting its use to lightweight packaging, and there is still room for improvement in terms of various properties required to meet the needs of its use as a packaging material.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-241359

[0008] Patent Document 2: Japanese Patent Application Publication No. 2020-196791

[0009] Patent Document 3: Japanese Patent Application Publication No. 2020-55157 Summary of the Invention

[0010] The object of the present invention is to provide a laminate containing polyethylene and having excellent recyclability, heat resistance or strength, as well as a package containing the laminate and packaged articles.

[0011] According to one aspect of the present invention, a laminate is provided, comprising sequentially a substrate layer, an adhesive layer, and a sealant layer, wherein the substrate layer and the sealant layer comprise polyethylene, and the degree of crystallinity of the substrate layer, measured by the parallel beam method of X-ray diffraction in a diffraction angle range of 10° to 30°, is 35% or more, which is the ratio of the crystallization peak area to the total peak area.

[0012] According to another aspect of the invention, a laminate as described above is provided, further comprising an intermediate layer containing polyethylene between the substrate layer and the sealant layer.

[0013] According to another aspect of the present invention, a laminate as described above is provided, wherein the degree of crystallinity of the intermediate layer, measured by the parallel beam method of X-ray diffraction in the range of diffraction angles of 10° to 30°, is 35% or more, which is the ratio of the crystallization peak area to the total peak area.

[0014] According to another aspect of the invention, a laminate as described above is provided, wherein the degree of crystallinity of the intermediate layer, measured by parallel beam X-ray diffraction in the range of diffraction angles of 10° to 30°, is less than 35% as the ratio of the crystallization peak area to the total peak area.

[0015] According to another aspect of the invention, a laminate as described in any of the above aspects is provided, which further comprises a protective layer with the substrate layer sandwiched in the middle, serving as the outermost layer facing the sealant layer.

[0016] According to another aspect of the invention, a laminate as described above is provided, wherein the protective layer comprises a thermosetting resin.

[0017] According to another aspect of the present invention, a laminate as described in any of the above aspects is provided, wherein the substrate layer is a biaxially stretched film.

[0018] Alternatively, according to another aspect of the invention, a laminate as described in any of the above aspects is provided, wherein the substrate layer is a uniaxially stretched film.

[0019] According to another aspect of the present invention, a laminate as described in any of the above aspects is provided, which further comprises a gas barrier layer existing between the substrate layer and the sealant layer.

[0020] According to another aspect of the invention, a laminate as described in any of the above aspects is provided, wherein the adhesive layer is gas-barrier.

[0021] According to another aspect of the invention, a laminate as described in any of the above aspects is provided, wherein the sealant layer is white.

[0022] According to another aspect of the present invention, a laminate as described in any of the above aspects is provided, wherein polyethylene accounts for 90% or more by mass in the laminate.

[0023] According to another aspect of the present invention, a laminate as described in any of the above aspects is provided, wherein the adhesive layer comprises a first adhesive layer and a second adhesive layer, the first adhesive layer is present between the substrate layer and the intermediate layer, and the second adhesive layer is present between the intermediate layer and the sealant layer.

[0024] According to another aspect of the invention, a packaging body is provided, comprising the laminate described in any of the preceding aspects.

[0025] According to another aspect of the invention, a packaging body as described above is provided, which is a stand-up pouch.

[0026] According to another aspect of the invention, a packaging article is provided, comprising a packaging body as described in any of the foregoing aspects and contents contained therein.

[0027] Invention Effects

[0028] According to the present invention, a laminate comprising polyethylene and having excellent recyclability, heat resistance or strength is provided, as well as a package body and packaged articles comprising the laminate. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view schematically illustrating the laminate of the first embodiment of the present invention.

[0030] Figure 2 To illustrate Figure 1 A cross-sectional view of a modified example of the laminate shown.

[0031] Figure 3 This is a cross-sectional view schematically illustrating the laminate of the second embodiment of the present invention.

[0032] Figure 4 This is a cross-sectional view schematically illustrating the laminate of the third embodiment of the present invention.

[0033] Figure 5 This is a cross-sectional view schematically illustrating the laminate of the fourth embodiment of the present invention.

[0034] Figure 6 This is a cross-sectional view schematically illustrating the laminate of the fifth embodiment of the present invention.

[0035] Figure 7 This is a cross-sectional view schematically illustrating the laminate of the sixth embodiment of the present invention.

[0036] Figure 8This is a cross-sectional view schematically illustrating the laminate of the seventh embodiment of the present invention.

[0037] Figure 9 This is a cross-sectional view schematically illustrating the laminate of the eighth embodiment of the present invention.

[0038] Figure 10 The diagram is schematically illustrating the packaged article according to the ninth embodiment of the present invention.

[0039] Figure 11 The diagram is schematically illustrating the packaged article according to the tenth embodiment of the present invention.

[0040] Figure 12 The diagram is schematically illustrating the packaged article according to the eleventh embodiment of the present invention. Detailed Implementation

[0041] The following is a reference to the appendix. Figure 1 The embodiments of the present invention will be described below. The embodiments described below are embellishments of any of the above aspects. The matters described below may be incorporated into the above aspects individually or in combination.

[0042] Furthermore, the embodiments shown below are examples used to illustrate the structure of the technical concept of the present invention, and the technical concept of the present invention is not limited to the material, shape, and structure of the constituent parts described below. Various modifications can be made to the technical concept of the present invention within the scope of the claims as defined in the claims.

[0043] Furthermore, elements with the same or similar functions are represented by the same reference numerals in the accompanying drawings, and repeated descriptions are omitted. Therefore, matters mentioned in one embodiment can also be applied to other embodiments unless otherwise specified. Additionally, the drawings are schematic diagrams, and the relationship between dimensions in one direction and dimensions in other directions, or the relationship between the dimensions of one component and the dimensions of other components, may differ from reality.

[0044] <1> First Implementation Method

[0045] <1.1>Laminated bodies

[0046] Figure 1 This is a cross-sectional view schematically illustrating the laminate of the first embodiment of the present invention.

[0047] Figure 1 The laminate 10A1 shown comprises a substrate layer 1, a printing layer 4, an adhesive layer 3, and a sealant layer 2 in sequence.

[0048] The substrate layer 1 and the sealant layer 2 contain polyethylene. Preferably, the polyethylene content in the laminate 10A1 is 90% by mass or more. Here, the proportion of polyethylene in the laminate refers to the proportion of the total amount of polyethylene in the total amount of resin material in each layer constituting the laminate. By making the polyethylene content 90% by mass or more, high recyclability can be achieved.

[0049] <1.2> Substrate Layer

[0050] The substrate layer 1 comprises polyethylene. Preferably, the substrate layer 1 is formed of polyethylene. The crystallinity of the substrate layer 1, measured by the parallel beam method of X-ray diffraction within a diffraction angle range of 10° to 30°, is 35% or more, which is the ratio of the crystallized peak area to the total peak area. Here, the crystallinity of the substrate layer 1 is a value obtained using the measurement method described later.

[0051] In the laminate 10A1 of the present invention, the heat resistance of the substrate layer 1 is improved by having a crystallinity of 35% or more. Therefore, when using the laminate 10A1 as a packaging material and processing it in a bag-making machine, there is no need to reduce the bag-making speed, resulting in excellent processing suitability.

[0052] In addition, by having a crystallinity of 35% or more for the substrate layer 1, the elongation of the substrate layer 1 is reduced and the printability is improved.

[0053] The polyethylene contained in the substrate layer 1 can be a homopolymer of ethylene or a copolymer of ethylene with other monomers. When the polyethylene is a copolymer of ethylene with other monomers, the proportion of ethylene in the copolymer is, for example, 80 mol% or more.

[0054] Other monomers include, for example, α-olefins. According to one 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.

[0055] Polyethylene can be a copolymer of ethylene with one of vinyl acetate and acrylate.

[0056] The substrate layer 1 is, for example, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or ultra-low-density polyethylene (VLDPE).

[0057] Here, the density of high-density polyethylene is 0.942 g / cm³. 3 The density of medium-density polyethylene is 0.930 g / cm³. 3Above and below 0.942 g / cm³ 3 The density of low-density polyethylene is 0.910 g / cm³. 3 Above and below 0.930 g / cm 3 The density of linear low-density polyethylene is 0.910 g / cm³. 3 Above and less than 0.930cm 3 Ultra-low density polyethylene has a density of less than 0.910 g / cm³. 3 .

[0058] Furthermore, the density was obtained using a method based on JIS K7112:1999.

[0059] The polyethylene contained in the substrate layer 1 can also be biomass-derived polyethylene. For example, green polyethylene (manufactured by Braskem) can be used as a biomass-derived polyethylene.

[0060] Alternatively, the polyethylene contained in the substrate layer 1 can also be polyethylene obtained by mechanical recycling. Here, mechanical recycling refers to crushing the recycled polyethylene film, then washing the crushed film with alkali to remove dirt and foreign matter from the film surface, and then drying it under high temperature and reduced pressure to allow the pollutants remaining inside the film to diffuse, thereby purifying the polyethylene film.

[0061] Alternatively, the polyethylene contained in the substrate layer 1 may also be polyethylene obtained by chemical recycling.

[0062] The melting point of the substrate layer 1 is preferably in the range of 100°C to 140°C, more preferably in the range of 120°C to 140°C. Furthermore, the melting point is a value obtained using a method based on JIS K7121-1987.

[0063] The substrate layer 1 can be an unstretched film or a stretched film. The substrate layer 1 is preferably a stretched film. When the substrate layer 1 has a crystallinity of 35% or more and is a stretched film, it has the following effects: Specifically, it exhibits particularly excellent heat resistance and strength. Furthermore, the elongation of the substrate layer 1 is reduced, and its printability is improved. In addition, in this specification, the term "film" does not include the concept of thickness.

[0064] When the substrate layer 1 is a stretch film, it can be either a uniaxial stretch film or a biaxial stretch film. When a uniaxial stretch film is used as the substrate layer 1, the heat resistance during bag making, i.e., the sealing performance described later, is further improved. When a biaxial stretch film is used as the substrate layer 1, the drop strength of the packaged items using the laminate 10A1 as packaging material is improved.

[0065] Furthermore, whether the stretched film is a uniaxial or biaxial stretched film can be determined by performing an in-plane measurement using wide-angle X-ray diffraction, as explained below. The X-ray diffraction pattern obtained by this measurement contains information related to the orientation of the molecular chains present on the film surface.

[0066] When a polymer film is uniaxially stretched, it exhibits a higher-order structure known as a Shish-Kebab structure. This Shish-Kebab structure is formed by Shish structures, which are extended chain crystals, and Kebab structures, which are lamellar crystals. In the uniaxially stretched film, this higher-order structure is arranged with a high order parameter; therefore, the X-ray diffraction pattern obtained from the above measurements of the uniaxially stretched film will contain sharp diffraction peaks. That is, when the above measurements are performed on the uniaxially stretched film, distinct diffraction peaks will appear. Furthermore, "distinct diffraction peaks" refers to diffraction peaks with a full width at half maximum (FWHM) of less than 10°.

[0067] In the manufacture of biaxially stretched films, stretching is performed in a specific direction, followed by stretching in a direction perpendicular to the previous direction. Therefore, although the aforementioned higher-order structure is produced through the initial stretching, this higher-order structure is disrupted by the second stretching. Consequently, when the biaxially stretched film is measured as described above, the diffraction peaks in the resulting X-ray diffraction pattern become broader. That is, no obvious diffraction peaks appear when the biaxially stretched film is measured as described above.

[0068] As mentioned above, the X-ray diffraction patterns obtained by the above measurements are different in uniaxially stretched films and biaxially stretched films. Therefore, it is possible to distinguish whether the stretched film is a uniaxially stretched film or a biaxially stretched film based on this.

[0069] The film can be manufactured using known methods such as casting or blow molding. Alternatively, the substrate layer 1 can be a multilayer polyethylene film obtained by co-extruding polyethylene of different densities. Stretched films can be obtained, for example, by stretching a film obtained by forming polyethylene using a T-die method or blow molding. The substrate layer 1 can be a uniaxially stretched film or a biaxially stretched film.

[0070] The haze of the substrate layer 1 is preferably 20% or less, more preferably 10% or less. Furthermore, the haze value is obtained using a method based on JIS K 7136:2000.

[0071] The thickness of the substrate layer 1 is preferably in the range of 10 μm to 200 μm. For example, the thickness of the substrate layer 1 is in the range of 10 μm to 50 μm, or 15 μm to 50 μm, or 12 μm to 35 μm. When the substrate layer 1 is too thin, the strength of the laminate 10A1 is easily reduced. When the substrate layer 1 is too thick, the processability of the laminate 10A1 is easily reduced.

[0072] The substrate layer 1 is preferably surface-treated. This treatment can improve the adhesion between the substrate layer 1 and the layers adjacent to it.

[0073] There are no particular limitations on the surface treatment method. Examples of surface treatments include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen and / or nitrogen, and arc discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

[0074] The substrate layer 1 may further include additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modified resins.

[0075] The proportion of polyethylene in the substrate layer 1 is preferably 50% by mass or more, more preferably 80% by mass or more. According to one example, the substrate layer 1 is formed of polyethylene. According to another example, the substrate layer 1 is formed of polyethylene and additives.

[0076] The substrate layer 1 can be colored, for example, it can be white.

[0077] As described above, the substrate layer 1 has a crystallinity of 35% or more. Although the printing layer 4 is disposed on the inner surface side of the substrate layer 1, the patterns or text displayed on the printing layer 4 can be seen with good visibility. From this point of view, the crystallinity of the substrate layer 1 is preferably 40% or more, more preferably 50% or more. The crystallinity is in the range of 50% to 75% according to one example. In addition, the polyethylene containing layer with a crystallinity of 35% or more also has excellent puncture strength, as will be explained below. From this point of view, the crystallinity of the substrate layer 1 is preferably 40% or more, more preferably 50% or more.

[0078] Polyethylene, being a crystalline polymer, possesses both crystalline and amorphous portions. Polyethylene with a high degree of crystallinity has a higher proportion of crystalline portions. These crystalline portions govern the elastic component of the resin's viscoelastic behavior; therefore, a higher degree of crystallinity results in increased film rigidity.

[0079] Due to the influence of this viscoelastic behavior, the deformation accompanying the plastic deformation of the resin also increases in films with high crystallinity. As a result, the film exhibits an effect of suppressing resin deformation in the face of instantaneous impact, making it less prone to damage. Therefore, the laminate 10A1, which includes a substrate 1 containing polyethylene and has a crystallinity of 35% or more, exhibits excellent resistance to instantaneous impact, and packaged items using the laminate 10A1 as packaging material are less likely to break (damage) due to drops. In other words, it exhibits excellent resistance to damage.

[0080] The degree of crystallinity of the substrate layer 1 can be adjusted by controlling the stretching of the polyethylene film used in the substrate layer 1 or the thermal history during or after film manufacturing. For example, the degree of crystallinity increases when the film is slowly cooled after film formation, and decreases when it is rapidly cooled. In addition, the degree of crystallinity can be increased by adding additives such as crystallizing nucleating agents.

[0081] <Method for Determining the Degree of Crystallinity>

[0082] The crystallinity of substrate layer 1 was determined using X-ray diffraction with a parallel beam method. An example of a method for determining crystallinity is described below.

[0083] First, the X-ray diffraction pattern of substrate layer 1 was obtained using a wide-angle X-ray diffractometer manufactured by Rigaku Corporation, employing out-of-plane measurement to perform 2θ / θ scanning over a diffraction angle range of 10° to 30°. The X-rays used were characteristic CuKα X-rays, which were parallelized using multilayer mirrors to ensure they were incident on substrate layer 1. A scintillation detector equipped with a flat collimator was used in the light-receiving unit.

[0084] Using the obtained X-ray diffraction pattern, the peak area of ​​the crystalline component and the halo pattern area of ​​the amorphous component are obtained. The proportion of the peak area of ​​the crystalline component in the sum of these areas is used as the degree of crystallinity to calculate.

[0085] When the substrate layer 1 has multiple layers, the degree of crystallinity of any of the outermost surfaces of the substrate layer 1 is measured.

[0086] When the substrate layer 1 is a polyethylene film, when scanning within a diffraction angle range of 10° to 30°, two sharp peaks of the crystalline component and a broad halo pattern of the amorphous component corresponding to the (110) and (200) planes are observed. After separating and analyzing these peaks, the area of ​​the crystalline component peak and the area of ​​the amorphous component halo pattern are calculated, and the degree of crystallinity is obtained using the following formula (1).

[0087] Degree of crystallinity = Peak area of ​​crystalline component / (Peak area of ​​crystalline component + Halo pattern area of ​​amorphous component) (1)

[0088] As a known X-ray diffraction method besides the parallel beam method, the focused method is prone to affecting the measurement results when dealing with samples with uneven surfaces, such as resin films, due to the displacement of the measurement surface, resulting in peak broadening. In contrast, in the parallel beam method, even with samples with uneven surfaces, the displacement of the measurement surface has a very small impact on the measurement results.

[0089] On the other hand, the substrate layer 1 is preferably uniaxially stretched or biaxially stretched. As described above, as a method for their identification, the in-plane method using X-ray diffraction can be used. In this in-plane method, the X-ray incident angle θ and the angle 2θ at which the diffracted X-rays are detected by the detector are fixed to the diffraction peaks corresponding to specific crystal planes in the out-of-plane method described above. For example, the angles θ and 2θ at which the diffraction peaks corresponding to the (110) plane of the polyethylene film are detected. In this state, the diffraction pattern is obtained by scanning the film as the object of measurement in the in-plane direction.

[0090] When performing in-plane measurements on a uniaxially stretched film that has undergone uniaxial stretching in the mechanical direction (MD), a diffraction pattern with sharp diffraction peaks corresponding to the (110) plane at a position with an angle 2θ of approximately ±90° can be obtained when the MD direction is defined as 0°. On the other hand, for films that have undergone biaxial stretching, the higher-order structure obtained by uniaxial stretching is disrupted by the second stretching, resulting in reduced anisotropy, and therefore a diffraction pattern with sharp diffraction peaks corresponding to the (110) plane cannot be obtained. Therefore, in-plane measurement can be used as an example of a method to distinguish between uniaxially stretched films and biaxially stretched films.

[0091] <1.3> Sealant layer

[0092] The sealant layer 2 faces the substrate layer 1. The sealant layer 2 comprises polyethylene. Preferably, the sealant layer 2 is formed of polyethylene. As polyethylene, for example, the substances described above regarding the polyethylene contained in the substrate layer 1 can be used. The sealant layer 2 is preferably low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or ultra-high-density polyethylene (VLDPE), more preferably linear low-density polyethylene.

[0093] From an environmental impact perspective, polyethylene derived from biomass or recycled polyethylene is preferred.

[0094] The sealant layer 2 may further contain the aforementioned additives.

[0095] The proportion of polyethylene in the sealant layer 2 is preferably 50% by mass or more, more preferably 80% by mass or more. According to one example, the sealant layer 2 is formed of polyethylene. According to yet another example, the sealant layer 2 is formed of polyethylene and additives.

[0096] The sealant layer 2 can be transparent or opaque. When opaque, it is preferred that the sealant layer 2 be white. A transparent sealant layer 2 in the laminate 10A1 makes the contents easily visible when used in the packaging. An opaque sealant layer 2 in the laminate 10A1 ensures that the contents do not obstruct the visibility of the image displayed on the printed layer 4 when used in the packaging. In particular, a white sealant layer 2 enhances the visibility of the image displayed on the printed layer 4.

[0097] The thickness of the sealant layer 2 can be appropriately set considering the shape of the packaging bag or the weight of the contents, for example, it can be 30 to 150 μm.

[0098] The sealant layer 2 is, for example, an unstretched polyethylene resin film or a layer formed by melt extrusion of polyethylene.

[0099] <1.4> Printing Layer

[0100] The printed layer 4 is disposed on the surface of the substrate layer 1 facing the sealant layer 2, i.e., on the inner and outer surfaces of the substrate layer 1. Furthermore, the location of the printed layer 4 is not limited. That is, the printed layer 4 can also be disposed on the surface of the substrate layer 1, and can be disposed at any location between the substrate layer 1 and the sealant layer 2. For example, when the laminate 10A1 further includes an intermediate layer described later, the printed layer 4 can be disposed on any surface of the intermediate layer. Additionally, the laminate 10A1 may include multiple printed layers. The printed layer 4 may also be omitted.

[0101] The printing ink used in printing layer 4 is not particularly limited as long as it has adhesion to polyethylene. Printing layer 4 may be composed, for example, of inks in which various pigments, extender pigments, plasticizers, drying agents, and stabilizers are added to conventionally used ink binder resins such as urethane-based, acrylic-based, nitrocellulose-based, rubber-based, and vinyl chloride-based inks. Biomass-derived inks are preferred. As for the printing method, known printing methods such as offset printing, gravure printing, flexographic printing, and screen printing, or known coating methods such as roller coating, air knife coating, and gravure coating can be used. Furthermore, opaque inks are also preferred. Examples include white, black, silver inks, and dark brown pigments.

[0102] <1.5> Adhesive layer

[0103] The adhesive layer 3 bonds the substrate layer 1, which has the printed layer 4, to the sealant layer 2. The adhesive layer 3 contains at least one type of adhesive. The adhesive can be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. Furthermore, the adhesive can be a solvent-free adhesive or a solvent-based adhesive.

[0104] Examples of adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, polyamine-based adhesives, epoxy-based adhesives, urethane-based adhesives, rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenolic adhesives, and olefin-based adhesives. Adhesives containing biomass components are also preferred. Gas-barrier adhesives, such as polyamine-based adhesives or urethane-based adhesives, are preferred. Specific examples of gas-barrier adhesives include "Maxive" manufactured by Mitsubishi GAS Chemical Co., Ltd., and "Paslim" manufactured by DIC Co., Ltd.

[0105] The adhesive layer 3 can also be a cured resin composition comprising polyester polyol, isocyanate compound, and phosphoric acid modified compound. This adhesive layer 3 can further improve the oxygen barrier and water vapor barrier properties of the laminate 10A1.

[0106] 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.

[0107] The adhesive layer 3 can be formed, for example, by applying it onto the sealant layer 2 using conventionally known methods such as direct gravure roller coating, gravure roller coating, coincidence coating, reverse roller coating, spraying, and transfer roller coating, and then drying it.

[0108] <1.6> Effects

[0109] The aforementioned laminate 10A1 exhibits excellent heat resistance and recyclability. This will be explained below.

[0110] The manufacturing of packaging bags generally involves the following steps: bringing the sealant layers of a laminate into contact with each other, clamping the contacting portions with a jig, and applying pressure and heat to cause the contact areas to fuse and bond (heat seal). The jigs of the heat sealing machine become extremely hot, exposing the surface of the substrate layer in direct contact with the jig to this high temperature. As a result, when using polyethylene with poor heat resistance in the substrate layer, problems such as heat damage to the substrate layer surface and adhesion to the jig may occur. Therefore, existing laminates using polyethylene in the substrate layer suffer from narrow suitable bag-making temperatures and low productivity.

[0111] The inventors measured the crystallinity of various polyethylenes and found that when the crystallinity of the substrate layer 1 was 35% or higher, the substrate layer 1 exhibited excellent heat resistance. Therefore, the laminate 10A1 also exhibited excellent heat resistance, achieving particularly good heat-sealing suitability. In the laminate 10A1, the substrate layer 1 is typically made of polyethylene, which is generally considered to lack heat resistance. Therefore, by achieving a crystallinity of 35% or higher for the substrate layer 1, the heat-sealing temperature range for bag making is widened, allowing the packaging to be manufactured without reducing productivity or causing poor appearance due to shrinkage of the seal.

[0112] Because the laminate 10A1 has such excellent heat resistance, its surface characteristics can be easily measured by using the crystallinity of the substrate layer 1 as an indicator, thus making it easy to stabilize its quality as a packaging material.

[0113] Furthermore, since laminate 10A1 has a base layer 1 mainly composed of polyethylene and a heat-sealing layer, it is easy to make the proportion of polyethylene 90% by mass or more. Therefore, laminate 10A1 also has excellent recyclability.

[0114] <1.7> Variation Example

[0115] The laminate 10A1 can have various deformations.

[0116] Figure 2 To illustrate Figure 1 A cross-sectional view of a modified example of the laminate shown. Figure 2 The laminate 10A2 shown is identical to the laminate 10A1 except that it further includes an inorganic compound layer 5 between the substrate layer 1 and the printed layer 4. The inorganic compound layer 5 is a thin film formed of inorganic compounds, such as inorganic oxides like aluminum oxide or silicon oxide, and functions as a gas barrier layer to inhibit the permeation of oxygen or water vapor.

[0117] <Inorganic Compound Layer>

[0118] The inorganic compound layer 5 can be formed by coating or by vapor deposition of inorganic compounds.

[0119] Examples of inorganic compounds contained in the inorganic compound layer 5 include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. The inorganic compound layer 5 is preferably a vapor-deposited film formed from a metal oxide. From the viewpoint of transparency and barrier properties, aluminum oxide, silicon oxide, and magnesium oxide can be selected as the metal oxide. Furthermore, considering cost, aluminum oxide and silicon oxide are selected as the metal oxide. Furthermore, from the viewpoint of excellent traction and stretchability during processing, silicon oxide is more preferably used as the metal oxide. By making the inorganic compound layer 5 a vapor-deposited film formed from a metal oxide, high barrier properties can be obtained with an extremely thin layer that does not affect the recyclability of the laminate 10A2.

[0120] Vaporized films formed from metal oxides are transparent, which makes it less likely for users holding packaging materials formed from laminates to mistakenly believe that metal foil is being used, compared to vaporized films formed from metal.

[0121] The thickness of the vapor-deposited film formed from alumina is preferably 5 nm or more and 30 nm or less. A thickness of 5 nm or more provides sufficient gas barrier properties. A thickness of 30 nm or less helps suppress cracking caused by deformation due to internal stress, thus preventing a decrease in gas barrier properties. Furthermore, when the film thickness exceeds 30 nm, costs tend to increase due to the increased material usage and longer film formation time, making it less desirable from an economic point of view. From the same perspective, a thickness of 7 nm or more and 15 nm or less is more preferable for the vapor-deposited film formed from alumina.

[0122] The thickness of the vapor-deposited film formed from silicon oxide is preferably 10 nm or more and 50 nm or less. A thickness of 10 nm or more provides sufficient gas barrier properties. Furthermore, a thickness of 50 nm or less helps suppress cracking caused by deformation due to internal stress, thus preventing a decrease in gas barrier properties. Moreover, when the film thickness exceeds 50 nm, costs tend to increase due to the increased material usage and longer film formation time, making it less desirable from an economic point of view. From the same perspective, a thickness of 20 nm or more and 40 nm or less is more preferable for the vapor-deposited film formed from silicon oxide.

[0123] The inorganic compound layer 5 can be formed, for example, using vacuum film deposition. In vacuum film deposition, physical vapor deposition (PVD) or chemical vapor deposition (CVD) methods can be used. Examples of PVD methods include vacuum evaporation, sputtering, and ion plating, but are not limited to these. Examples of CVD methods include thermal CVD, plasma CVD, and photoCVD, but are not limited to these.

[0124] Among the aforementioned vacuum film deposition methods, resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, induction heating vacuum evaporation, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD) are particularly preferred. Of these, vacuum evaporation is currently the most preferred method considering productivity. As for the heating method in vacuum evaporation, electron beam heating, resistance heating, or induction heating are preferred.

[0125] <Anchor Coating>

[0126] As described in the second embodiment, the laminate 10A2 may further include an anchor coating (not shown). The anchor coating can be formed on the surface of the substrate layer 1 on the side where the inorganic compound layer 5 is formed, using a known anchoring agent. This improves the adhesion of the inorganic compound layer 5 formed from the metal oxide. Examples of anchoring agents include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoint of heat resistance and interlayer adhesion strength, a polyester-based polyurethane resin is preferred as the anchoring agent.

[0127] <Covering>

[0128] Furthermore, as described in the second embodiment, the laminate 10A2 may further include a coating layer (not shown) between the inorganic compound layer 5 and the printed layer 4. The combination of the inorganic compound layer 5 and the coating layer can function as a gas barrier layer. Hereinafter, when the inorganic compound layer 5 is referred to as a gas barrier layer, the combination of the inorganic compound layer 5 and the coating layer may also be referred to as a gas barrier layer.

[0129] The laminate 10A2 also exhibits excellent heat resistance. Furthermore, since the inorganic compound layer 5 is substantially transparent, the image displayed on the printed layer 4 can be seen from the surface side even when the inorganic compound layer 5 is disposed between the substrate layer 1 and the printed layer 4. Moreover, the laminate 10A2 also demonstrates excellent recyclability.

[0130] In addition, to provide light-shielding properties, a metal vapor-deposited layer can be provided between the substrate layer 1 and the sealant layer 2 in the laminates 10A1 and 10A2. When the laminate further includes an intermediate layer described later, a metal vapor-deposited layer can also be provided on any surface of the intermediate layer. An aluminum vapor-deposited layer is an example of a metal vapor-deposited layer.

[0131] Furthermore, although it has been stated that sealant layer 2 can be opaque, substrate layer 1 can also be opaque. For example, substrate layer 1 can be white. When the laminate further includes an intermediate layer described later, the intermediate layer can be opaque. For example, the intermediate layer can be white.

[0132] <2> Second Implementation Method

[0133] <2.1> Laminated Body

[0134] Figure 3 This is a cross-sectional view schematically illustrating the laminate of the second embodiment of the present invention.

[0135] Figure 3 The laminate 10B shown sequentially comprises a protective layer 6, a substrate layer 1, a gas barrier layer 5, a printing layer 4, an adhesive layer 3, and a sealant layer 2. The gas barrier layer 5 included in the laminate 10B is formed of an inorganic compound layer, or of an inorganic compound layer and a coating layer. The laminate 10B is identical to the laminate 10A1 except that it further includes the protective layer 6 disposed on the surface of the substrate layer 1 and the gas barrier layer 5 present between the substrate layer 1 and the printing layer 4. The substrate layer 1, printing layer 4, adhesive layer 3, and sealant layer 2 included in the laminate 10B can be those described in the first embodiment.

[0136] <2.2> Protective Layer

[0137] The laminate 10B, as the outermost layer, has a protective layer 6.

[0138] The protective layer 6 comprises a thermosetting resin. There are no particular limitations on the thermosetting resin as long as it possesses heat resistance; examples include polyurethane resin, polyester resin, polyamide resin, polyamide-imide resin, acrylic resin, epoxy resin, and water-soluble polymers. The protective layer 6 may comprise one type of thermosetting resin, or it may comprise two or more types.

[0139] The protective layer 6 preferably comprises a water-soluble polymer, and more preferably an organic-inorganic composite layer comprising an organometallic compound.

[0140] Examples of water-soluble polymers include polyvinyl alcohol-based polymers, starch-methylcellulose-carboxymethylcellulose polysaccharides, and hydroxyl-containing polymers such as acrylic polyols. In one embodiment, the protective layer 6 preferably comprises a polyvinyl alcohol-based hydroxyl-containing polymer that may be contained in the coating layer of the gas barrier layer 5 described later.

[0141] The protective layer 6, preferably an organometallic compound, contains at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, or a reaction product of a metal alkoxide or its hydrolysate. Examples of metal alkoxides include tetraethoxysilane [Si(OC2H5)4] and aluminum triisopropoxy [Al(OC3H7)3], with the general formula M(OR). n As shown.

[0142] In addition, the protective layer 6, as an organometallic compound, preferably further comprises 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.

[0143] In one embodiment, the protective layer 6 can be formed using a coating liquid used to form the coating layer that serves as the gas barrier layer 5 described later. Alternatively, when the laminate 10B comprises an inorganic compound layer and a coating layer as the gas barrier layer 5, the protective layer 6 can be a layer formed using the same coating liquid used to form the coating layer.

[0144] The protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. By having a heat-resistant protective layer 6 on the outermost layer, laminate 10B can ensure heat sealability and productivity even when using polyethylene resin with poor heat resistance as the substrate.

[0145] The thickness of the protective layer 6 is preferably in the range of 0.3 μm to 3 μm. If the protective layer 6 is too thin, it tends to be difficult to achieve high heat resistance. If the protective layer 6 is too thick, it becomes difficult to ensure that the resin curing film is fully dried during the manufacturing process of the laminate 10B.

[0146] <2.3> Gas Barrier Layer

[0147] The gas barrier layer 5, for example, improves the oxygen barrier and water vapor barrier properties of the laminate 10B.

[0148] The gas barrier layer 5 is formed of an inorganic compound layer, or of an inorganic compound layer and a coating layer. When the gas barrier layer 5 is formed of an inorganic compound layer and a coating layer, it is preferable to sequentially stack the inorganic compound layer and the coating layer starting from the side of the substrate layer 1. The gas barrier layer 5 can be formed by coating, or it can be formed by vapor deposition of inorganic compounds. The inorganic compound layer is the same as that described in the variation of Embodiment 1.

[0149] The coating 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 can also be added to the coating solution.

[0150] The coating layer may be, for example, an organic-inorganic composite layer comprising at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolysate of a metal alkoxide, and a water-soluble polymer. The organic-inorganic composite layer may further comprise 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.

[0151] Examples of metal alkoxides and their hydrolysates contained in organic-inorganic composite layers include tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3], which have the general formula M(OR). n The shown substances and their hydrolysates. A substance may contain one of these substances alone, or two or more of these substances in combination.

[0152] From the viewpoint of oxygen barrier properties, the total content of metal alkoxides, their hydrolysates, or their reaction products in the coating solution used to form the organic-inorganic composite layer can be, for example, 40% by mass or more, 50% by mass or more, or 65% by mass or more. Alternatively, the total content of metal alkoxides, their hydrolysates, or their reaction products in the aforementioned coating solution can be, for example, 70% by mass or less.

[0153] The water-soluble polymers included in the organic-inorganic composite layer are not particularly limited; examples include polysaccharides such as polyvinyl alcohol, starch-methylcellulose-carboxymethylcellulose, and hydroxyl-containing polymers such as acrylic polyols. From the viewpoint of further improving oxygen barrier properties, it is preferable that the water-soluble polymers include polyvinyl alcohol-based water-soluble polymers. The number-average molecular weight of the water-soluble polymers is, for example, 40,000 to 180,000.

[0154] The water-soluble polymer based on polyvinyl alcohol contained in the organic-inorganic composite layer can be obtained by saponifying (and partially saponifying) polyvinyl acetate. This water-soluble polymer can have tens of percent of acetic acid groups remaining, or only a few percent of acetic acid groups remaining.

[0155] The content of water-soluble polymers in the coating liquid used to form the organic-inorganic composite layer can be, for example, 15% by mass or more, or even 20% by mass or more, from the viewpoint of oxygen barrier properties. Furthermore, the content of water-soluble polymers in the aforementioned coating liquid can be, for example, 50% by mass or less, or even 45% by mass or less, from the viewpoint of oxygen barrier properties.

[0156] Silane coupling agents used in organic-inorganic composite layers include those having organic functional groups. Examples of such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropylmethyldimethoxysilane. A single silane coupling agent selected from these, its hydrolysate, and their reaction products can be used, or two or more can be used in combination.

[0157] As silane coupling agents, those with an epoxy group as an organic functional group are preferred. Examples of epoxy-containing silane coupling agents include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Epoxy-containing silane coupling agents may also have organic functional groups other than epoxy groups, such as vinyl, amino, methacryl, or urea groups. A single silane coupling agent selected from these, its hydrolysate, and their reaction products can be used, or two or more can be used in combination.

[0158] Silane coupling agents with organic functional groups, their hydrolysates, or their reaction products can further improve the oxygen barrier properties and 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 hydrolysates, or their reaction products have epoxy groups and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction between the epoxy groups and the hydroxyl groups of PVA can further improve the oxygen barrier properties and adhesion to adjacent layers.

[0159] From the viewpoint of oxygen barrier properties, 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 can be, for example, 1% by mass or more, or even 2% by mass or more. Furthermore, from the viewpoint of oxygen barrier properties, the total content of the silane coupling agent, its hydrolysate, and their reaction products in the aforementioned coating solution can be, for example, 15% by mass or less, or even 12% by mass or less.

[0160] The thickness of the coating layer is preferably 50 nm or more and 1000 nm or less, more preferably 100 nm or more and 500 nm or less. When the thickness of the gas barrier coating layer is 50 nm or more, it tends to achieve more sufficient gas barrier properties, and when it is 1000 nm or less, it tends to maintain sufficient flexibility.

[0161] Preferably, the gas barrier layer 5 undergoes the surface treatment described above. This improves the adhesion between the gas barrier layer 5 and adjacent layers.

[0162] In addition, nanocomposite materials can also be used as the material for the gas barrier layer 5.

[0163] In the laminate 10B, the printed layer 4 is located between the gas barrier layer 5 and the adhesive layer 3, but it can also be located anywhere between the protective layer 6 and the sealant layer 2. Since the substrate layer 1 is transparent, even if the printed layer 4 is included at any location between the substrate layer 1 and the sealant layer 2, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10B is viewed from the protective layer 6 side.

[0164] <Anchor Coating>

[0165] The laminate 10B may further include an anchor coating (not shown) on the main surface of the substrate layer 1 facing the gas barrier layer 5. This improves the adhesion of the gas barrier layer 5. Examples of anchor coatings include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoint of heat resistance and interlayer adhesion strength, polyester-based polyurethane resins are preferred as anchor coatings.

[0166] The proportion of polyethylene in the laminate 10B is, for example, 90% by mass or more. Thus, the laminate 10B is composed of a single material with high recyclability.

[0167] <2.4> Effects

[0168] Like laminate 10A1, laminate 10B includes a substrate layer 1 comprising polyethylene with a crystallinity within the aforementioned range. Therefore, laminate 10B, like laminate 10A1, exhibits excellent heat resistance.

[0169] Furthermore, the laminate 10B includes a protective layer 6 on its outermost layer. As described above, the protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. Therefore, the laminate 10B achieves superior heat resistance, and in particular, better heat-sealing suitability. Consequently, with respect to the laminate 10B, when the above configuration is adopted, the temperature range for heat sealing during bag making is widened, and it is less likely to result in reduced productivity or poor appearance due to shrinkage of the sealing portion.

[0170] Furthermore, the aforementioned gas barrier layer 5, namely the inorganic compound layer and the coating layer, is essentially transparent. Therefore, even if the gas barrier layer 5 is provided between the substrate layer 1 and the printing layer 4, the image displayed on the printing layer 4 can still be seen from the surface side.

[0171] That is, the laminate 10B has excellent heat resistance and recyclability.

[0172] <3> Third Implementation Method

[0173] <3.1>Laminated bodies

[0174] Figure 4 This is a cross-sectional view schematically illustrating the laminate of the third embodiment of the present invention.

[0175] Figure 4The laminate 10C shown sequentially comprises a protective layer 6, a substrate layer 1, an inorganic compound layer 5, a coating layer 7, a printing layer 4, an adhesive layer 3, and a sealant layer 2. The polyethylene content of the laminate 10C is 90% by mass or more. The laminate 10C has the same layer structure as the laminate 10B described in the second embodiment, which includes an inorganic compound layer and a coating layer starting from the substrate layer 1 side as a gas barrier layer 5. The protective layer 6, substrate layer 1, inorganic compound layer 5, coating layer 7, printing layer 4, adhesive layer 3, and sealant layer 2 of the laminate 10C can be those described in the second embodiment. In the laminate 10C, the inorganic compound layer 5, coating layer 7, and printing layer 4 can be omitted.

[0176] <Anchor Coating>

[0177] The laminate 10C is the same as the laminate 10B in the second embodiment, except that an anchor coating (not shown) may be further included on the main surface of the substrate layer 1 facing the inorganic compound layer 5. This improves the adhesion of the inorganic compound layer 5. Examples of anchor coatings include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoint of heat resistance and interlayer adhesion strength, polyester-based polyurethane resins are preferred as anchor coatings.

[0178] <3.3> Effects

[0179] Since the laminate 10C has the same layer structure as the laminate 10B, it performs the same effect as the laminate 10B.

[0180] <4> Fourth Implementation Method

[0181] <4.1> Laminated Body

[0182] Figure 5 This is a cross-sectional view schematically illustrating the laminate of the fourth embodiment of the present invention.

[0183] Figure 5 The laminate 10D shown sequentially comprises a substrate layer 1, a first adhesive layer 3A, a gas barrier layer 5, an intermediate layer 8, a printed layer 4, a second adhesive layer 3B, and a sealant layer 2. The laminate 10D is the same as the laminate 10B except that it further includes the intermediate layer 8. Additionally, the laminate 10D includes the first adhesive layer 3A and the second adhesive layer 3B instead of the adhesive layer 3. The substrate layer 1, printed layer 4, and sealant layer 2 included in the laminate 10D can be those described in the first embodiment.

[0184] <4.2> Gas Barrier Layer

[0185] The gas barrier layer 5, for example, improves the oxygen barrier and water vapor barrier properties of the laminate 10D. The gas barrier layer 5 is, for example, a metal layer, an inorganic oxide layer, a resin-containing layer, or a combination of two or more thereof. Assuming microwave heating is performed using a microwave oven, the gas barrier layer 5 is preferably an inorganic oxide layer, a resin-containing layer, or a combination thereof.

[0186] The gas barrier layer 5 can be formed by coating, by melt forming, or by vapor deposition of inorganic oxides. Alternatively, the gas barrier layer 5 can be a metal foil such as aluminum foil, or it can be vapor-deposited with metals such as aluminum.

[0187] As inorganic oxides, for example, silicon oxide, boron oxide, or aluminum oxide, magnesium oxide, calcium oxide, potassium oxide, tin oxide, sodium oxide, titanium oxide, lead oxide, zirconium oxide, and yttrium oxide can be used.

[0188] The resin-containing layer can be formed, for example, by coating. In this case, a coating liquid 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 can also be added to this coating liquid.

[0189] When forming a resin-containing layer using melt molding, extrusion molding techniques such as T-die molding or blow molding can be used, for example. In melt molding, for example, the aforementioned resin or a mixture of the aforementioned resin and additives is heated and melted, and a film or sheet used as the gas barrier layer 5 is obtained using a T-die or blow molding. Then, the film or sheet is bonded to the intermediate layer 8.

[0190] The thickness of the gas barrier layer 5, for example, if it is an inorganic oxide layer, is preferably in the range of 1 nm to 200 nm. A thickness of 1 nm or more provides excellent oxygen and water vapor barrier properties. A thickness of 200 nm or less keeps manufacturing costs very low and reduces the likelihood of cracking due to external forces such as bending or pulling, thus suppressing degradation of barrier properties. Alternatively, if it is a resin-containing layer, the thickness is preferably in the range of 0.1 μm to 10 μm, more preferably in the range of 0.2 μm to 5 μm. A thickness of 0.2 μm or more provides excellent oxygen and water vapor barrier properties. A thickness of 10 μm or less keeps manufacturing costs very low.

[0191] Preferably, the gas barrier layer 5 undergoes the surface treatment described above. This improves the adhesion between the gas barrier layer 5 and adjacent layers.

[0192] In addition, nanocomposite materials can also be used as the material for the gas barrier layer 5.

[0193] <4.3> Intermediate Layer

[0194] The intermediate layer 8 comprises polyethylene. As polyethylene, for example, the aforementioned material described regarding the polyethylene contained in the base layer 1 can be used.

[0195] The polyethylene contained in the intermediate layer 8 may be the same as or different from the polyethylene contained in the base layer 1. In addition, the intermediate layer 8 may further contain the aforementioned additives.

[0196] The proportion of polyethylene in the interlayer 8 is preferably 50% by mass or more, more preferably 80% by mass or more. According to one example, the interlayer 8 is formed of polyethylene. According to yet another example, the interlayer 8 is formed of polyethylene and additives.

[0197] The intermediate layer 8 has a crystallinity of 35% or more. Preferably, the intermediate layer 8 has a crystallinity of 40% or more, more preferably 50% or more. The crystallinity of the intermediate layer 8 is, in one example, in the range of 50% to 75%.

[0198] The intermediate layer 8, with a crystallinity of 35% or higher, improves the strength of the laminate 10D, particularly its puncture strength. Therefore, the laminate 10D exhibits excellent strength, especially its puncture strength. Laminates with a high polyethylene content are less rigid than other laminates, thus increasing the likelihood of bending when used as packaging materials. Increased bending increases the possibility of pinholes, but the laminate 10D, with its excellent puncture strength, is less prone to pinholes. From this perspective, the intermediate layer 8, with a crystallinity of 35% or higher, is preferably a stretch film; more preferably, both the substrate layer 1 and the intermediate layer 8 are stretch films. In this case, the stretch film constituting the intermediate layer 8 can be the same as or different from the stretch film constituting the substrate layer 1.

[0199] The melting point of the intermediate layer 8 is preferably in the range of 100°C to 140°C, and more preferably in the range of 120°C to 140°C.

[0200] The thickness of the intermediate layer 8 is preferably in the range of 10 μm to 200 μm, more preferably in the range of 15 μm to 50 μm.

[0201] The intermediate layer 8 can be colored, for example, it can be white.

[0202] As the intermediate layer 8, it can be manufactured using known methods such as casting or blow molding. Alternatively, the intermediate layer 8 can also be a multi-layered polyethylene film obtained by co-extruding polyethylene of different densities. A stretched film, for example, can be obtained by stretching a film obtained by forming polyethylene using a T-die method or blow molding.

[0203] Furthermore, in this embodiment, an intermediate layer with a crystallinity of less than 35% can also be used. By using an intermediate layer with a crystallinity of less than 35%, the strength of the laminate 10D, particularly its drop strength, can be improved. An unstretched film is preferred as the intermediate layer with a crystallinity of less than 35%.

[0204] <4.4> Adhesive layer

[0205] The adhesives used to form the first adhesive layer 3A and the second adhesive layer 3B may be the same or different. The adhesives used to form the first adhesive layer 3A and the second adhesive layer 3B include at least one type of adhesive.

[0206] The adhesive can be a one-component curing adhesive, a two-component curing adhesive, or an uncured adhesive. Furthermore, the adhesive can be a solvent-free adhesive or a solvent-based adhesive.

[0207] Examples of adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, polyamine-based adhesives, epoxy-based adhesives, urethane-based adhesives, rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenolic adhesives, and olefin-based adhesives. Adhesives containing biomass components are also preferred. The adhesive is preferably a polyamine-based adhesive or a urethane-based adhesive with gas barrier properties.

[0208] The first adhesive layer 3A and the second adhesive layer 3B can also be cured products of a resin composition comprising a polyester polyol, an isocyanate compound, and a phosphoric acid modified compound. This laminate 10D of the first adhesive layer 3A and the second adhesive layer 3B exhibits excellent oxygen and water vapor barrier properties.

[0209] The thicknesses of the first adhesive layer 3A and the second adhesive layer 3B are 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.

[0210] The first adhesive layer 3A and the second adhesive layer 3B can be formed, for example, by applying them onto the substrate layer 1 using existing known methods such as direct gravure roller coating, gravure roller coating, coincidence coating, reverse roller coating, spraying, and transfer roller coating, and then drying them.

[0211] also, Figure 5 The intermediate laminate 10D includes a gas barrier layer 5 between the first adhesive layer 3A and the intermediate layer 8. The laminate 10D may also include a gas barrier layer 5 between the intermediate layer 8 and the second adhesive layer 3B.

[0212] in addition, Figure 5The intermediate printing layer 4 is disposed between the intermediate layer 8 and the second adhesive layer 3B. The printing layer 4 can also be disposed anywhere between the substrate layer 1 and the sealant layer 2. Preferably, the printing layer 4 is disposed between the first adhesive layer 3A and the substrate layer 1. In this case, when viewing the laminate 10B from the substrate layer 1 side, the pattern displayed by the printing layer 4 is easily and clearly visible.

[0213] Additionally, an anchor coating may be formed on the surface of the substrate layer 1 facing the first adhesive layer 3A. Furthermore, the gas barrier layer 5 and the printing layer 4 may be omitted.

[0214] Polyethylene accounts for, for example, 90% by mass or more in the laminate 10D. Thus, the laminate 10D is composed of a single material with high recyclability.

[0215] <4.5> Effect

[0216] The laminate 10D described above is the same as laminate 10A1, and includes a substrate layer 1 comprising polyethylene with a crystallinity within the aforementioned range. Therefore, laminate 10D, like laminate 10A1, exhibits excellent heat resistance.

[0217] Furthermore, the laminate 10D includes an intermediate layer 8 with a crystallinity within the aforementioned range. This intermediate layer 8 enhances the strength of the laminate 10D, particularly its puncture strength. Therefore, the laminate 10D exhibits excellent strength, especially its puncture strength.

[0218] Furthermore, since the substrate layer 1, intermediate layer 8 and sealant layer 2 of the laminate 10D all contain polyethylene, the laminate has excellent recyclability.

[0219] Furthermore, as mentioned above, laminates with a high polyethylene content are less rigid than other laminates, thus increasing the likelihood of bending when used as packaging materials. Increased bending increases the possibility of pinholes, but 10D laminates, with their excellent puncture strength, are less prone to pinholes.

[0220] Here, the "puncture strength" of laminate 10D is the value obtained by piercing laminate 10D from the substrate layer 1 side using the method specified in JIS Z1707:2019 "General Rules for Plastic Films for Food Packaging". Specifically, a needle with a diameter of 1 mm and a semi-circular tip is inserted into laminate 10D from the substrate layer 1 side at a speed of 50 mm / min, and the maximum force until the needle penetrates is measured. This measurement is performed multiple times, and the arithmetic mean of the maximum forces is obtained as the puncture strength.

[0221] <5> Fifth Implementation Method

[0222] <5.1> Laminated Body

[0223] Figure 6This is a cross-sectional view schematically illustrating the laminate of the fifth embodiment of the present invention.

[0224] Figure 6 The laminate 10E shown sequentially comprises a protective layer 6, a substrate layer 1, a printed layer 4, a first adhesive layer 3A, an intermediate layer 8, a gas barrier layer 5, a second adhesive layer 3B, and a sealant layer 2. The laminate 10E is the same as the laminate 10D except for the following: The laminate 10E further includes the protective layer 6. In the laminate 10E, the inorganic compound layer 5 is present between the second adhesive layer 3B and the intermediate layer 8. In the laminate 10E, the printed layer 4 is present between the substrate layer 1 and the first adhesive layer 3A. The substrate layer 1, printed layer 4, first adhesive layer 3A, intermediate layer 8, second adhesive layer 3B, and sealant layer 2 included in the laminate 10D can be those described in the fourth embodiment.

[0225] <5.2> Protective Layer

[0226] The protective layer 6 comprises a thermosetting resin. There are no particular limitations on the thermosetting resin as long as it possesses heat resistance; examples include polyurethane resin, polyester resin, polyamide resin, polyamide-imide resin, acrylic resin, epoxy resin, and water-soluble polymers. The protective layer 6 may comprise one type of thermosetting resin, or it may comprise two or more types.

[0227] In one embodiment, the protective layer 6 is preferably an organic-inorganic composite layer comprising a water-soluble polymer and an organometallic compound.

[0228] Examples of water-soluble polymers include polyvinyl alcohol-based polymers, starch-methylcellulose-carboxymethylcellulose polysaccharides, and hydroxyl-containing polymers such as acrylic polyols. In one embodiment, the protective layer 6 preferably comprises a polyvinyl alcohol-based hydroxyl-containing polymer that may be contained in the coating layer of the gas barrier layer 5 described later.

[0229] The protective layer 6, preferably an organometallic compound, contains at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, or a reaction product of a metal alkoxide or its hydrolysate. Examples of metal alkoxides include tetraethoxysilane [Si(OC2H5)4] and aluminum triisopropoxy [Al(OC3H7)3], with the general formula M(OR). n As shown.

[0230] In addition, the protective layer 6, as an organometallic compound, preferably further comprises 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.

[0231] In one embodiment, the protective layer 6 can be formed using a coating liquid used to form the coating layer that serves as the gas barrier layer 5 described later. Alternatively, when the laminate 10E comprises an inorganic compound layer and a coating layer as the gas barrier layer 5, the protective layer 6 can be a layer formed using the same coating liquid used to form the coating layer.

[0232] The laminate 10E, by having a heat-resistant protective layer 6 on the outermost layer, ensures heat-sealing performance and productivity even when using polyethylene resin, which has poor heat resistance, as the base material.

[0233] The thickness of the protective layer 6 is preferably in the range of 0.3 μm to 3 μm. If the protective layer 6 is too thin, it tends to be difficult to achieve high heat resistance. If the protective layer 6 is too thick, it becomes difficult to ensure that the resin curing film is fully dried during the manufacturing process of the laminate 10E.

[0234] <5.3> Gas Barrier Layer

[0235] The gas barrier layer 5, for example, improves the oxygen barrier and water vapor barrier properties of the laminate 10E.

[0236] The gas barrier layer 5 is formed of an inorganic compound layer or of an inorganic compound layer and a coating layer. When the gas barrier layer 5 is formed of an inorganic compound layer and a coating layer, it is preferable to stack the inorganic compound layer and the coating layer sequentially starting from the side of the intermediate layer 8.

[0237] The gas barrier layer 5 can be formed by coating or by vapor deposition of inorganic compounds.

[0238] Examples of inorganic compounds contained in the inorganic compound layer include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. The inorganic compound layer is preferably a vapor-deposited film formed from a metal oxide. From the viewpoint of transparency and barrier properties, aluminum oxide, silicon oxide, and magnesium oxide can be selected as the metal oxide. Furthermore, considering cost, aluminum oxide and silicon oxide are selected as the metal oxide. Furthermore, from the viewpoint of excellent tensile strength during processing, silicon oxide is more preferably used as the metal oxide. By making the inorganic compound layer contained in the gas barrier layer 5 a vapor-deposited film formed from a metal oxide, high barrier properties can be obtained with an extremely thin layer that does not affect the recyclability of the laminate 10E.

[0239] Vaporized films formed from metal oxides are transparent, which makes it less likely for users holding packaging materials formed from laminates to mistakenly believe that metal foil is being used, compared to vaporized films formed from metal.

[0240] The thickness of the vapor-deposited film formed from alumina is preferably 5 nm or more and 30 nm or less. A thickness of 5 nm or more provides sufficient gas barrier properties. Furthermore, a thickness of 30 nm or less helps suppress cracking caused by deformation due to internal stress, thus preventing a decrease in gas barrier properties. Moreover, when the film thickness exceeds 30 nm, costs tend to increase due to the increased material usage and longer film formation time, making it less desirable from an economic point of view. From the same perspective, a thickness of 7 nm or more and 15 nm or less is more preferable for the vapor-deposited film formed from alumina.

[0241] The thickness of the vapor-deposited film formed from silicon oxide is preferably 10 nm or more and 50 nm or less. A thickness of 10 nm or more provides sufficient gas barrier properties. Furthermore, a thickness of 50 nm or less helps suppress cracking caused by deformation due to internal stress, thus preventing a decrease in gas barrier properties. Moreover, when the film thickness exceeds 50 nm, costs tend to increase due to the increased material usage and longer film formation time, making it less desirable from an economic point of view. From the same perspective, a thickness of 20 nm or more and 40 nm or less is more preferable for the vapor-deposited film formed from silicon oxide.

[0242] Inorganic compound layers can be formed, for example, using vacuum film deposition. In vacuum film deposition, physical vapor deposition (PVD) or chemical vapor deposition (CVD) methods can be used. Examples of PVD methods include vacuum evaporation, sputtering, and ion plating, but are not limited to these. Examples of CVD methods include thermal CVD, plasma CVD, and photochemical CVD, but are not limited to these.

[0243] Among the aforementioned vacuum film deposition methods, resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, induction heating vacuum evaporation, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD) are particularly preferred. Of these, vacuum evaporation is currently the most preferred method considering productivity. As for the heating method in vacuum evaporation, electron beam heating, resistance heating, or induction heating are preferred.

[0244] The coating 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 can also be added to the coating solution.

[0245] The coating layer may be, for example, an organic-inorganic composite layer comprising at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolysate of a metal alkoxide, and a water-soluble polymer. The organic-inorganic composite layer may further comprise 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.

[0246] Examples of metal alkoxides and their hydrolysates contained in organic-inorganic composite layers include tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3], which have the general formula M(OR). n The shown substances and their hydrolysates. A substance may contain one of these substances alone, or two or more of these substances in combination.

[0247] From the viewpoint of oxygen barrier properties, the total content of metal alkoxides, their hydrolysates, or their reaction products in the coating solution used to form the organic-inorganic composite layer can be, for example, 40% by mass or more, 50% by mass or more, or 65% by mass or more. Alternatively, the total content of metal alkoxides, their hydrolysates, or their reaction products in the aforementioned coating solution can be, for example, 70% by mass or less.

[0248] The water-soluble polymers included in the organic-inorganic composite layer are not particularly limited; examples include polysaccharides such as polyvinyl alcohol, starch-methylcellulose-carboxymethylcellulose, and hydroxyl-containing polymers such as acrylic polyols. From the viewpoint of further improving oxygen barrier properties, it is preferable that the water-soluble polymers include polyvinyl alcohol-based water-soluble polymers. The number-average molecular weight of the water-soluble polymers is, for example, 40,000 to 180,000.

[0249] The water-soluble polymer based on polyvinyl alcohol contained in the organic-inorganic composite layer can be obtained by saponifying (and partially saponifying) polyvinyl acetate. This water-soluble polymer can have tens of percent of acetic acid groups remaining, or only a few percent of acetic acid groups remaining.

[0250] The content of water-soluble polymers in the coating liquid used to form the organic-inorganic composite layer can be, for example, 15% by mass or more, or even 20% by mass or more, from the viewpoint of oxygen barrier properties. Furthermore, the content of water-soluble polymers in the aforementioned coating liquid can be, for example, 50% by mass or less, or even 45% by mass or less, from the viewpoint of oxygen barrier properties.

[0251] Silane coupling agents used in organic-inorganic composite layers include those having organic functional groups. Examples of such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropylmethyldimethoxysilane. A single silane coupling agent selected from these, its hydrolysate, and their reaction products can be used, or two or more can be used in combination.

[0252] As a silane coupling agent, it is preferred to use one with an epoxy group as the organic functional group. Examples of epoxy-containing silane coupling agents include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Epoxy-containing silane coupling agents may also have organic functional groups other than epoxy groups, such as vinyl, amino, methacrylate, or urea groups. A single silane coupling agent selected from these, its hydrolysate, and their reaction products can be used, or two or more can be used in combination.

[0253] Silane coupling agents with organic functional groups, their hydrolysates, or their reaction products can further improve the oxygen barrier properties and 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 hydrolysates, or their reaction products have epoxy groups and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction between the epoxy groups and the hydroxyl groups of PVA can further improve the oxygen barrier properties and adhesion to adjacent layers.

[0254] From the viewpoint of oxygen barrier properties, 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 can be, for example, 1% by mass or more, or even 2% by mass or more. Furthermore, from the viewpoint of oxygen barrier properties, the total content of the silane coupling agent, its hydrolysate, and their reaction products in the aforementioned coating solution can be, for example, 15% by mass or less, or even 12% by mass or less.

[0255] Preferably, the gas barrier layer 5 undergoes the surface treatment described above. This improves the adhesion between the gas barrier layer 5 and adjacent layers.

[0256] In addition, nanocomposite materials can also be used as the material for the gas barrier layer 5.

[0257] The thickness of the coating layer is preferably 50 nm or more and 1000 nm or less, more preferably 100 nm or more and 500 nm or less. When the thickness of the gas barrier coating layer is 50 nm or more, it tends to achieve more sufficient gas barrier properties, and when it is 1000 nm or less, it tends to maintain sufficient flexibility.

[0258] <Anchor Coating>

[0259] The laminate 10E may further have an anchor coating (not shown) on the surface of the intermediate layer 8 on the side where the gas barrier layer 5 is formed. Alternatively, the laminate 10E may further have an anchor coating (not shown) on the main surface of the substrate layer 1 facing the first adhesive layer 3A. The anchor coating can be formed using a known anchoring agent. This improves the adhesion of the inorganic compound layer formed from the metal oxide. Examples of anchoring agents include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoint of heat resistance and interlayer adhesion strength, a polyester-based polyurethane resin is preferred as the anchoring agent.

[0260] also, Figure 6 The laminate 10E shown includes a printed layer 4 between the substrate layer 1 and the first adhesive layer 3A, but the printed layer 4 can also be included anywhere between the protective layer 6 and the sealant layer 2. Since the substrate layer 1 and the intermediate layer 8 included in the laminate 10E are transparent, the pattern displayed by the printed layer 4 is clearly visible when viewing the laminate 10E from the protective layer 6 side, regardless of the location of the printed layer 4. According to one example, it is preferable that the pattern displayed by the printed layer 4 is more clearly visible when it is included between the intermediate layer 8 and the protective layer 6.

[0261] in addition, Figure 6 In the laminate 10E, a gas barrier layer 5 is included on the surface of the intermediate layer 8 facing the sealant layer 2, but the laminate 10E may also include a gas barrier layer 5 on the surface of the intermediate layer 8 facing the substrate layer 1.

[0262] Polyethylene accounts for, for example, 90% by mass or more in the laminate 10E. Thus, the laminate 10E is composed of a single material with high recyclability.

[0263] <5.4> Effects

[0264] The laminate 10E described above is the same as laminate 10A1, having a polyethylene containing layer with a crystallinity within the aforementioned range as the substrate layer 1. Therefore, laminate 10E, like laminate 10A1, exhibits excellent heat resistance.

[0265] Furthermore, the laminate 10E includes a protective layer 6. As described above, the protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. Therefore, the laminate 10E achieves superior heat resistance, and in particular, better heat-sealing suitability. Consequently, with respect to the laminate 10E, when the above configuration is adopted, the temperature range for heat sealing during bag making is widened, and it is less likely to cause a decrease in productivity.

[0266] Furthermore, the laminate 10E includes an intermediate layer 8 with a crystallinity within the aforementioned range. This intermediate layer 8 enhances the strength of the laminate 10E, particularly its puncture strength. Therefore, the laminate 10E exhibits excellent strength, especially its puncture strength.

[0267] Furthermore, since the substrate layer 1, intermediate layer 8 and sealant layer 2 of the laminate 10E all contain polyethylene, the laminate has excellent recyclability.

[0268] In addition, laminates with a high polyethylene content are less rigid than other laminates, thus requiring more bending when used as packaging materials. Increased bending increases the likelihood of pinholes, but laminate 10E, with its excellent puncture strength, is less prone to pinholes.

[0269] Here, since the substrate layer 1 and the intermediate layer 8 in the laminate 10E are transparent, the pattern displayed on the printed layer 4 can be clearly seen when viewed from the protective layer 6 side, regardless of where the printed layer 4 is contained between the substrate layer 1 and the sealant layer 2. Furthermore, the contents are highly visible in the packaged article containing the aforementioned laminate 10E.

[0270] <6> Sixth Implementation Method

[0271] <6.1> Laminated Body

[0272] Figure 7 This is a cross-sectional view schematically illustrating the laminate of the sixth embodiment of the present invention.

[0273] Figure 7 The laminate 10F shown sequentially comprises a protective layer 6, a substrate layer 1, a printing layer 4, a first adhesive layer 3A, an intermediate layer 8, a gas barrier layer 5, a second adhesive layer 3B, and a sealant layer 2. The laminate 10F is identical to the laminate 10E except that the crystallinity of the intermediate layer 8 is less than 35%. That is, of the layers included in the laminate 10F, the layers other than the intermediate layer 8—namely, the protective layer 6, the substrate layer 1, the printing layer 4, the first adhesive layer 3A, the gas barrier layer 5, the second adhesive layer 3B, and the sealant layer 2—can be those described in the fifth embodiment.

[0274] <6.2> Intermediate Layer

[0275] The intermediate layer 8 comprises polyethylene. As polyethylene, for example, the material described above regarding the polyethylene contained in the base layer 1 can be used. The intermediate layer 8 is, for example, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or ultra-low-density polyethylene (VLDPE).

[0276] The polyethylene contained in the intermediate layer 8 may be the same as or different from the polyethylene contained in the base layer 1. In addition, the intermediate layer 8 may further contain the aforementioned additives.

[0277] The proportion of polyethylene in the interlayer 8 is preferably 50% by mass or more, more preferably 80% by mass or more. According to one example, the interlayer 8 is formed of polyethylene. According to yet another example, the interlayer 8 is formed of polyethylene and additives.

[0278] The crystallinity of the intermediate layer 8 is less than 35%. Preferably, the crystallinity of the intermediate layer 8 is 30% or less. Preferably, the crystallinity of the intermediate layer 8 is 15% or more.

[0279] An intermediate layer 8 with a crystallinity of less than 35% can improve the strength of the laminate 10F, especially its drop strength. An unstretched film is preferred as this intermediate layer 8. From the viewpoint of drop strength, it is preferable that the intermediate layer 8 is an unstretched film with a crystallinity of less than 35%, and the substrate layer 1 is a stretched film with a crystallinity of 35% or more.

[0280] Furthermore, in this embodiment, an intermediate layer with a crystallinity of 35% or higher can also be used. Using an intermediate layer with a crystallinity of 35% or higher can improve the strength of the laminate 10, particularly its puncture strength. A stretch film is preferred as the intermediate layer with a crystallinity of 35% or higher.

[0281] The thickness of the intermediate layer 8 is preferably in the range of 10 μm to 200 μm, more preferably in the range of 15 μm to 50 μm.

[0282] As the intermediate layer 8, it can be manufactured using known methods such as casting or blow molding. Alternatively, as the base layer 1, a multilayer polyethylene film obtained by co-extruding polyethylene of different densities can be used.

[0283] <Anchor Coating>

[0284] The laminate 10F may further have an anchor coating (not shown) on the surface of the intermediate layer 8 on the side where the gas barrier layer 5 is formed. Alternatively, the laminate 10F may further have an anchor coating (not shown) on the main surface of the substrate layer 1 facing the first adhesive layer 3A. As the anchor coating, the one described in the fifth embodiment may be used.

[0285] also, Figure 7 The intermediate laminate 10F includes a gas barrier layer 5 between the intermediate layer 8 and the second adhesive layer 3B, but the laminate 10F may also include a gas barrier layer 5 between the first adhesive layer 3A and the intermediate layer 8.

[0286] in addition, Figure 7 The intermediate printing layer 4 is disposed between the substrate layer 1 and the first adhesive layer 3A, but the printing layer 4 is preferably disposed between the protective layer 6 and the first adhesive layer 3A. In this case, when the laminate 10F is viewed from the protective layer 6 side, the pattern displayed by the printing layer 4 can be easily and clearly seen.

[0287] In addition, the printing layer 4 and the gas barrier layer 5 can be omitted in the laminate 10F.

[0288] The proportion of polyethylene in the laminate 10F is, for example, 90% by mass or more. Thus, the laminate 10F is composed of a single material with high recyclability.

[0289] <6.3> Effects

[0290] The crystallinity of the substrate layer 1 of the aforementioned laminate 10F is within the range described above. Therefore, laminate 10F, like laminate 10A1, exhibits excellent heat resistance.

[0291] Furthermore, the laminate 10F includes a protective layer 6. As described above, the protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. Therefore, the laminate 10F achieves superior heat resistance, and in particular, better heat-sealing suitability. Consequently, with respect to the laminate 10F, when the above configuration is adopted, the temperature range for heat sealing during bag making is widened, and it is less likely to cause a decrease in productivity.

[0292] Furthermore, the laminate 10F includes an intermediate layer 8 with a crystallinity within the aforementioned range. This intermediate layer 8 enhances the strength of the laminate 10F, particularly its drop strength. Specifically, when used in packaging, the intermediate layer 8, located inside the base layer 1, is more flexible than the base layer 1. This structure is suitable for absorbing the impact generated when a packaged item using the laminate 10F as a packaging material is dropped. Consequently, packaged items using the laminate 10F as a packaging material are less prone to breakage (bag rupture) due to drops. Therefore, the laminate 10F exhibits excellent strength, particularly its drop strength.

[0293] Furthermore, since the substrate layer 1, intermediate layer 8 and sealant layer 2 all contain polyethylene, the laminate 10F has excellent recyclability.

[0294] <7> Seventh Implementation Method

[0295] <7.1> Laminated Body

[0296] Figure 8This is a cross-sectional view schematically illustrating the laminate of the seventh embodiment of the present invention.

[0297] Figure 8 The laminate 10G shown sequentially comprises a protective layer 6, a substrate layer 1, a printing layer 4, a first adhesive layer 3A, an intermediate layer 8, an inorganic compound layer 5, a coating layer 7, a second adhesive layer 3B, and a sealant layer 2. The polyethylene content of the laminate 10G is 90% by mass or more. The gas barrier layer 5 of the laminate 10G is formed from the inorganic compound layer and the coating layer in the same manner as in the laminate 10E of the fifth embodiment. The protective layer 6, substrate layer 1, printing layer 4, first adhesive layer 3A, intermediate layer 8, inorganic compound layer 5, coating layer 7, second adhesive layer 3B, and sealant layer 2 included in the laminate 10G can be those described in the fifth embodiment.

[0298] <7.2> Effects

[0299] Laminate 10G is the same as laminate 10A1, having a polyethylene containing layer as the base layer 1 with a crystallinity within the aforementioned range. Therefore, laminate 10G, like laminate 10A1, exhibits excellent heat resistance.

[0300] Furthermore, the laminate 10G includes a protective layer 6. As described above, the protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. Therefore, the laminate 10G achieves superior heat resistance, and in particular, better heat-sealing suitability. Consequently, with respect to the laminate 10G, when the above configuration is adopted, the temperature range for heat sealing during bag making is widened, and it is less likely to cause a decrease in productivity.

[0301] Furthermore, the laminate 10G includes an intermediate layer 8 with a crystallinity within the aforementioned range. This intermediate layer 8 enhances the strength of the laminate 10G, particularly its puncture strength. Therefore, the laminate 10G exhibits excellent strength, especially its puncture strength.

[0302] Furthermore, the substrate layer 1, intermediate layer 8, and sealant layer 2 of the laminate 10G all contain polyethylene, with the polyethylene content being 90% by mass or more. This laminate exhibits excellent recyclability.

[0303] In addition, laminates with a high polyethylene content are less rigid than other laminates, thus requiring more bending when used as packaging materials. Increased bending increases the likelihood of pinholes, but 10G laminates with excellent puncture strength are less prone to pinholes.

[0304] Here, since the substrate layer 1 and the intermediate layer 8 in the laminate 10G are transparent, the pattern displayed on the printed layer 4 can be clearly seen when viewed from the protective layer 6 side, regardless of where the printed layer 4 is contained between the substrate layer 1 and the sealant layer 2. Furthermore, the contents are highly visible in the packaged article containing the aforementioned laminate 10G.

[0305] <8> Eighth Implementation Method

[0306] <8.1> Laminated Body

[0307] Figure 9 This is a cross-sectional view schematically illustrating the laminate of the eighth embodiment of the present invention.

[0308] Figure 9 The laminate 10H shown sequentially comprises a protective layer 6, a substrate layer 1, a printing layer 4, a first adhesive layer 3A, an intermediate layer 8, an inorganic compound layer 5, a coating layer 7, a second adhesive layer 3B, and a sealant layer 2. The polyethylene content of the laminate 10H is 90% by mass or more. The gas barrier layer 5 of the laminate 10H is formed from the inorganic compound layer and the coating layer, similar to the case of the laminate 10F in the sixth embodiment. The protective layer 6, substrate layer 1, printing layer 4, first adhesive layer 3A, intermediate layer 8, inorganic compound layer 5, coating layer 7, second adhesive layer 3B, and sealant layer 2 included in the laminate 10H can be any of those described in the sixth embodiment.

[0309] <8.2> Effects

[0310] The crystallinity of the substrate layer 1 of laminate 10H is within the above-mentioned range. Therefore, laminate 10H, like laminate 10A1, exhibits excellent heat resistance.

[0311] Furthermore, the laminate 10H includes a protective layer 6. As described above, the protective layer 6 reduces heat damage to the surface of the laminate during heat sealing. Therefore, the laminate 10H achieves superior heat resistance, and in particular, better heat-sealing suitability. Consequently, with respect to the laminate 10H, when the above configuration is adopted, the temperature range for heat sealing during bag making is widened, and it is less likely to cause a decrease in productivity.

[0312] Furthermore, the laminate 10H includes an intermediate layer 8 with a crystallinity within the aforementioned range. This intermediate layer 8 enhances the strength of the laminate 10H, particularly its drop strength. Specifically, 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 generated when a packaged item using the laminate 10H as a packaging material is dropped. Consequently, packaged items using the laminate 10H as a packaging material are less prone to breakage (bag rupture) due to drops. Therefore, the laminate 10H exhibits excellent strength, particularly its drop strength.

[0313] Furthermore, the polyethylene content of laminate 10H is over 90% by mass. Therefore, laminate 10H also has excellent recyclability.

[0314] The printing layer 4 can be disposed on the surface of the substrate layer 1, on the surface of the intermediate layer 8, or on the back of the intermediate layer 8. In any case, the patterns or text displayed on the printing layer 4 can be seen with good visibility. Furthermore, the printing layer 4 can also be omitted.

[0315] <9> Ninth Implementation Method

[0316] Figure 10 The diagram is schematically illustrating the packaged article according to the ninth embodiment of the present invention.

[0317] Figure 10 The packaged item 100A shown includes a package body 110A and contents contained therein.

[0318] Packaging body 110A is a three-side sealed bag. Packaging body 110A includes a pair of main films. Each main film is any of the laminates described in the first to eighth embodiments, or a cut-out thereof. The main films are overlapped with their sealant layers facing each other, and the peripheries are heat-sealed together. Packaging body 110A has a slot in its heat-sealed portion as an easy-open structure.

[0319] The contents can be any of liquids, solids, and mixtures thereof. Examples of contents include food or pharmaceuticals.

[0320] <10> Tenth Implementation Method

[0321] Figure 11 The diagram is schematically illustrating the packaged article according to the tenth embodiment of the present invention.

[0322] Figure 11 The packaged article 100B shown includes a package body 110B and contents contained therein. The contents are, for example, the same as those described with respect to packaged article 100A.

[0323] Packaging body 110B is a stand-up pouch. Packaging body 110B comprises a pair of main films and a bottom film. Each film is any of the laminates described in the first to eighth embodiments, or a cut-out thereof.

[0324] A pair of main films are overlapped with their sealant layers facing each other, and their peripheries are heat-sealed together except for one end and its vicinity. The bottom film is folded in half so that it becomes a zigzag when viewed from the sealant layer side, and at the aforementioned end, the zigzag portion is held between the pair of main films so that it faces the other end of the main films. The portion of the bottom film, except for its central portion, is heat-sealed onto the pair of main films. In addition, the bottom films adhere their outer surfaces together at the bottom sides of the packaging body 110B.

[0325] The packaging body 110B has a slot in the portion between the heat-sealed main films as an easy-open structure. The easy-open structure can be configured such that the upper corner can be used as an opening when the packaged article 100B is opened. Alternatively, the packaged article 100B may further include the opening component and cap body described in the eleventh embodiment.

[0326] <11> Eleventh Implementation Method

[0327] Figure 12 The diagram is schematically illustrating the packaged article according to the eleventh embodiment of the present invention.

[0328] Figure 12 The packaged article 100C shown includes a package body 110C and contents contained therein. The contents are, for example, the same as those described with respect to packaged article 100A.

[0329] Packaging body 110G is a gusseted bag. Packaging body 110C includes container body 110C1, mouth part 110C2 and lid 110C3.

[0330] The container body 110C1 comprises a pair of main membranes and a pair of side membranes.

[0331] A pair of body films are overlapped such that their sealant layers face each other and clamp a portion of the opening member 110C2 at one end. The peripheries of these body films are heat-sealed onto the opening member 110C2 at the aforementioned end, while also heat-sealing each other in their vicinity. Additionally, the peripheries of these body films are heat-sealed together at their opposite ends, except for the areas on both sides.

[0332] Each side film is folded in a zigzag pattern when viewed from the sealant layer side. These side films are held between the two main films on either side, with the zigzag portions facing each other. A portion of the periphery of each side film is heat-sealed onto one of the main films, and the remaining portion is heat-sealed onto the other. Furthermore, the side films adhere their outer surfaces together at various locations on the upper and lower parts of the packaging body 110C.

[0333] In addition, the container body 110C1 may further include a bottom membrane.

[0334] As described above, the mouth component 110C2, while being held by the main body membrane, includes a portion for heat sealing. The mouth component 110C2 further includes a mouth protruding outward from the container body 110C1. The mouth has a generally cylindrical shape and external threads on its outer sidewall. The cap 110C3 has a bottomed cylindrical shape. The cap 110C3 has internal threads on its inner sidewall, engaging with the mouth of the mouth component 110C2.

[0335] Example

[0336] The following describes the results of experiments conducted in connection with this invention.

[0337] (1) Experiment A

[0338] (1.1) Fabrication of laminates

[0339] (1.1.1)Example 1A

[0340] Figure 2 The laminate 10A2 shown is manufactured using the following method.

[0341] First, a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% was prepared as the substrate layer. Furthermore, the crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0342] Next, silicon oxide (SiO2) is formed as an inorganic compound layer on one side of the substrate layer. x A vapor-deposited film is then formed on the inorganic compound layer. Afterward, a printed layer is formed on top of this layer.

[0343] Next, a dry lamination adhesive (urethane-based adhesive) is applied to the surface of the substrate layer where the printed layer is formed. Then, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) serving as a sealant layer is adhered to the substrate layer through this adhesive layer.

[0344] Create the stacked body as shown above.

[0345] (1.1.2) Example 2A

[0346] Except for omitting the inorganic compound layer, it is manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0347] (1.1.3) Example 3A

[0348] In addition to using polyamine-based gas barrier adhesives as adhesives to replace dry lamination adhesives (urethane-based adhesives), it is manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0349] (1.1.4)Example 4A

[0350] In addition to using a polyethylene film with a thickness of 25 μm and a crystallinity of 71.8% instead of a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% as the substrate layer, it was manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0351] (1.1.5) Example 5A

[0352] In addition to using a polyethylene film with a thickness of 25 μm and a crystallinity of 55.9% instead of a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% as the substrate layer, it was manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0353] (1.1.6)Example 6A

[0354] In addition to using a polyethylene film with a thickness of 25 μm and a crystallinity of 54.1% instead of a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% as the substrate layer, it was manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0355] (1.1.7) Example 7A

[0356] In addition to using a polyethylene film with a thickness of 30 μm and a crystallinity of 55.9% instead of a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% as the substrate layer, it was manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0357] (1.1.8)Example 8A

[0358] Except that a 40 μm thick linear low-density polyethylene (LLDPE) film is used instead of a 60 μm thick linear low-density polyethylene (LLDPE) film as a sealant layer, it is manufactured using the same method as in Example 1A. Figure 2The stacked body 10A2 shown.

[0359] (1.1.9) Example 9A

[0360] Except that a 120 μm thick linear low-density polyethylene (LLDPE) film is used instead of a 60 μm thick linear low-density polyethylene (LLDPE) film as a sealant layer, it is manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0361] (1.1.10)Example 10A

[0362] Except for the absence of an inorganic compound layer, and the use of a polyamine-based gas barrier adhesive instead of a dry lamination adhesive (urethane-based adhesive) as an adhesive, it is manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0363] (1.1.11)Example 11A

[0364] Except that it does not contain an inorganic compound layer, and uses a urethane-based gas barrier adhesive instead of a dry lamination adhesive (urethane-based adhesive) as an adhesive, it is manufactured using the same method as in Example 1A. Figure 2 The stacked body 10A2 shown.

[0365] (1.1.12) Comparative Example 1A

[0366] In addition to using a polyethylene film with a thickness of 32 μm and a crystallinity of 14.8% instead of a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% as the substrate layer, the laminate was manufactured using the same method as in Example 1A.

[0367] (1.1.13) Comparative Example 2A

[0368] In addition to using a polyethylene film with a thickness of 25 μm and a crystallinity of 20.6% instead of a polyethylene film with a thickness of 25 μm and a crystallinity of 58.5% as the substrate layer, the laminate was manufactured using the same method as in Example 1A.

[0369] (1.2) Measurement and evaluation methods

[0370] The substrate layer used in the manufacture of the above-mentioned laminate was subjected to in-plane measurement using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had a sharp diffraction peak corresponding to the (110) plane.

[0371] In addition, the sealing performance, heat resistance, visibility, and gas barrier properties of the above-mentioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, visibility, and gas barrier properties are described below.

[0372] (1.2.1) Evaluation method for sealing performance

[0373] The sample, obtained by cutting the laminate into 10cm squares, was folded in half with the sealant layer facing inwards, and then heat-sealed using a heat sealer. Specifically, the lower surface sealing temperature was first set to 100°C, and the upper surface sealing temperature was simultaneously set to 120°C, with a pressure of 0.1MPa applied for 1 second. Then, while confirming whether the sealing surface melted, the area in contact with the heat-sealing rod on the upper surface of the folded sample was observed. When neither the sealing surface nor the upper surface of the sample melted, the upper surface sealing temperature was increased in 10°C increments while maintaining the lower surface sealing temperature at 100°C, and the same pressure and observation were performed. The sealing performance was then evaluated using the following standards.

[0374] A: The sample surface was not melted and there were no problems with its appearance.

[0375] B: The sample has melted surface and has visual problems.

[0376] (1.2.2) Evaluation method for heat resistance

[0377] The sample obtained by cutting the laminate into 10cm squares is folded in half with the sealant layer facing inwards. Next, the lower surface sealing temperature of the heat sealer is set to 30°C, and the upper surface sealing temperature is set to 170°C. A pressure of 0.2MPa is applied to the folded sample for 1 second. Then, while confirming whether there is melting of the sealing surface, the area on the upper surface of the folded sample in contact with the heat sealant is observed to see if the sealant adheres to the heat sealant. The heat resistance is evaluated using the following standards.

[0378] A: The upper surface of the sample is not attached to the heat-sealing rod.

[0379] B: The upper surface of the sample is attached to the heat-sealing rod.

[0380] (1.2.3) Methods for evaluating visibility

[0381] The pattern displayed on the printed layer is observed visually from the substrate layer side, and its visibility is evaluated using the following criteria.

[0382] A: The pattern displayed on the printed layer can be clearly identified.

[0383] B: The pattern displayed on the printed layer is blurry and unclear.

[0384] (1.2.4) Evaluation method for gas barrier properties

[0385] After boiling the laminate, the oxygen transmission rate (OTR) was measured at 30°C and 70% relative humidity. This measurement was performed according to JIS K-7126, Method B. Furthermore, the gas barrier properties were evaluated by comparing the oxygen transmission rate with the following standards.

[0386] A: OTR less than 10cc / m 2 ·day·atm.

[0387] B: OTR is 10cc / m 2 ·day·atm and above.

[0388] (1.3) Results

[0389] The results of the above measurements and evaluations are shown in Tables 1-1 and 1-2 below.

[0390]

[0391]

[0392] As shown in Tables 1-1 and 1-2, laminates with a substrate layer crystallinity of 35% or higher exhibit good sealing performance, heat resistance, and visibility. In contrast, laminates with a substrate layer crystallinity of less than 35% show insufficient sealing performance, heat resistance, and visibility.

[0393] (2) Experiment B

[0394] (2.1) Fabrication of laminates

[0395] (2.1.1) Example 1B

[0396] Manufactured using the following methods Figure 3 The laminate 10B is shown. In addition, in this example, an anchor coating is further provided between the substrate layer 1 and the gas barrier layer 5, and the gas barrier layer 5 is provided with an inorganic compound layer and a coating layer.

[0397] First, the anchoring agent, protective layer, and coating liquid for forming the coating layer are prepared using the following method. In this example, the same coating liquid is used to form the protective layer and the coating layer.

[0398] (Preparation of anchoring agent)

[0399] Acrylic polyol and toluene diisocyanate were mixed in equal amounts relative to the number of OH groups in the acrylic polyol and the number of NCO groups in the toluene diisocyanate. The mixture was then diluted with ethyl acetate to achieve a total solids content (total amount of acrylic polyol and toluene diisocyanate) of 5% by mass. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture to achieve a total solids content of 5 parts by mass relative to 100 parts by mass of the total acrylic polyol and toluene diisocyanate. The mixture was then combined to prepare the anchoring agent.

[0400] (Preparation of coating liquid for forming protective and coating layers)

[0401] Liquids A, B, and C are mixed in a mass ratio of 70 / 20 / 10 to prepare a coating liquid (hereinafter referred to as "coating liquid") for forming a protective layer and a coating layer containing an organic-inorganic mixture.

[0402] Solution A: A hydrolyzed solution with a solid content of 5% by mass (SiO2 conversion) is obtained by adding 72.1g of 0.1N hydrochloric acid to 17.9g of tetraethoxysilane (Si(OC2H5)4) and 10g of methanol and stirring for 30 minutes.

[0403] Solution B: A 5% by mass water / methanol solution of polyvinyl alcohol (water:methanol mass ratio is 95:5).

[0404] Solution C: A hydrolyzed solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate with a mixture of water and isopropanol (water:isopropanol mass ratio of 1:1) to a solid content of 5% by mass.

[0405] As the substrate layer, a layer with a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.94 g / cm³ was prepared. 3 The polyethylene film. Furthermore, the degree of crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0406] Next, a corona treatment is applied to one side of the substrate layer. Then, the prepared coating liquid is applied to the corona-treated side of the substrate layer using a gravure coating method and dried to form a protective layer with a thickness of 0.5 μm (dry state) formed of an organic-inorganic mixture.

[0407] Next, corona treatment is applied to the other side of the substrate layer. Then, the anchoring agent is applied to the corona-treated side of the substrate layer using gravure coating to form an anchoring coating with a thickness of 0.1 μm (dry state).

[0408] Next, silicon oxide (SiO2) was formed using a vacuum evaporation apparatus with electron beam heating as the inorganic compound layer, with a thickness of 40 nm. x A vapor-deposited film is then formed. Next, the coating solution prepared above is applied onto the inorganic compound layer to form a coating layer with a thickness of 0.3 μm (dry state) formed from an organic-inorganic mixture.

[0409] Next, water-based flexible ink is printed onto the coating layer to form a printed layer.

[0410] Next, a dry lamination adhesive (urethane-based adhesive) is applied to the surface of the substrate layer where the printed layer is formed. Then, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) serving as a sealant layer is adhered to the substrate layer through this adhesive layer.

[0411] Create the stacked body as shown above.

[0412] (2.1.2) Example 2B

[0413] In addition to serving as the substrate layer, a film with a thickness of 25 μm, a crystallinity of 55.9%, a haze of 5.9%, and a density of 0.95 g / cm³ is used instead of the aforementioned polyethylene film with a crystallinity of 58.5%. 3 In addition to the polyethylene film, it is manufactured using the same method as in Example 1B. Figure 3 The laminate 10B shown is a biaxially stretched polyethylene film that has undergone single-sided corona treatment.

[0414] (2.1.3) Example 3B

[0415] Except for the absence of a protective layer, it is manufactured using the same method as in Example 2B. Figure 3 The layered body 10B shown.

[0416] (2.1.4)Example 4B

[0417] Except for forming a 0.5 μm thick protective layer from a urethane resin instead of coating a polyamide-imide resin, a 0.5 μm thick protective layer is manufactured using the same method as in Example 1B. Figure 3 The layered body 10B shown.

[0418] (2.1.5)Example 5B

[0419] In addition to forming a 1 μm thick protective layer from a urethane resin instead of a 0.5 μm thick protective layer from a coated polyamide-imide resin, the same method as in Example 1B was used to manufacture the protective layer. Figure 3 The layered body 10B shown.

[0420] (2.1.6) Example 6B

[0421] In addition to forming a 1 μm thick protective layer from ethylene-vinyl alcohol copolymer (EVOH) instead of coating a 0.5 μm thick protective layer with polyamide-imide resin, the same method as in Example 1B was used to manufacture the protective layer. Figure 3 The layered body 10B shown.

[0422] (2.1.7) Example 7B

[0423] Except for forming a 1 μm thick protective layer from acrylic resin instead of coating a 0.5 μm thick protective layer from polyamide-imide resin, the same method as in Example 1B was used to manufacture the protective layer. Figure 3 The layered body 10B shown.

[0424] (2.1.8) Comparative Example 1B

[0425] Except for the following, it is manufactured using the same method as in Example 1B. Figure 3 The laminate 10B shown is an example of a film without a protective layer. Furthermore, instead of the aforementioned polyethylene film with a crystallinity of 58.5%, a film with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm³ is used as the substrate layer. 3 The polyethylene film. The polyethylene film has undergone single-sided corona treatment.

[0426] (2.2) Measurement and evaluation methods

[0427] Regarding the substrate layer used in the manufacture of the above-mentioned laminate, in-plane measurements were performed using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had sharp diffraction peaks corresponding to the (110) plane.

[0428] In addition, the sealing performance, heat resistance, visibility, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, visibility, and recyclability are described below.

[0429] (2.2.1) Evaluation method for sealing performance

[0430] The sample obtained by cutting the laminate into 10cm squares is folded in half with the sealant layer facing inwards, and then heat-sealed using a heat sealer. Specifically, a pressure of 140°C and 0.1MPa is applied to the folded sample for 1 second. The area on the sample surface in contact with the heat-sealing rod is then observed, and the sealing performance is evaluated using the following standards.

[0431] A: The sample surface did not melt, and there is no problem with its appearance.

[0432] B: The sample surface is molten, resulting in visual problems.

[0433] (2.2.2) Evaluation method for heat resistance

[0434] The sample obtained by cutting the laminate into 10cm squares is folded in half with the sealant layer facing inwards. Next, the lower surface sealing temperature of the heat sealer is set to 30°C, and the upper surface sealing temperature is set to 170°C. A pressure of 0.2MPa is applied to the folded sample for 1 second. Then, while confirming whether there is melting of the sealing surface, the area on the upper surface of the folded sample in contact with the heat sealant is observed to see if the sealant adheres to the heat sealant. The heat resistance is evaluated using the following standards.

[0435] A: The upper surface of the sample is not attached to the heat-sealing rod.

[0436] B: The upper surface of the sample is attached to the heat-sealing rod.

[0437] In addition, for laminates with protective layers, the heat resistance was further evaluated using the same method as described above, except that the sealing temperature of the upper surface was set to 190°C.

[0438] (2.2.3) Methods for evaluating visibility

[0439] Visibility was evaluated using the methods described in (1.2.3).

[0440] (2.2.4) Evaluation method for recyclability

[0441] Calculate the proportion of polyethylene in the total mass of the laminate. Evaluate the recyclability of this proportion against the following standards. Here, rating A indicates excellent recyclability as a single material.

[0442] A: The proportion of polyethylene is over 90% by mass.

[0443] B: The proportion of polyethylene is less than 90% by mass.

[0444] (2.3) Results

[0445] The results of the above measurements and evaluations are shown in Table 2 below.

[0446]

[0447] As shown in Table 2, laminates with a substrate layer crystallinity of 35% or higher exhibit good recyclability, heat resistance, and visibility. Furthermore, laminates with a substrate layer crystallinity of 35% or higher and a protective layer also demonstrate excellent sealing performance. In contrast, laminates with a substrate layer crystallinity of less than 35% and no protective layer exhibit insufficient sealing performance, heat resistance, and visibility.

[0448] (3) Experiment C

[0449] (3.1) Fabrication of laminates

[0450] (3.1.1)Example 1C

[0451] Manufactured using the following methods Figure 4 The laminate 10C shown is further provided in this example, with an anchor coating layer between the substrate layer 1 and the inorganic compound layer 5.

[0452] First, the anchoring agent and the coating liquid for forming the coating layer were prepared using the same method as in Example 1B. Additionally, an organic solvent solution of polyamide-imide resin (with a non-volatile component concentration of 5% by mass) was prepared as the coating liquid for forming the protective layer.

[0453] As the substrate layer, a layer with a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.950 g / cm³ was prepared. 3 The polyethylene film was subjected to double-sided corona treatment. Furthermore, the degree of crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0454] Next, the above-prepared coating liquid containing polyamide-imide is applied to one corona-treated surface of the substrate layer using a gravure coating method and then dried to form a protective layer with a thickness of 0.5 μm.

[0455] Next, the anchoring agent is applied to another corona-treated surface of the substrate layer using a gravure coating method to form an anchoring coating with a thickness of 0.1 μm (dry state).

[0456] Next, silicon oxide (SiO2) was formed using a vacuum evaporation apparatus with electron beam heating as the inorganic compound layer, with a thickness of 40 nm. x Next, the coating liquid for forming the above-prepared coating layer is applied onto the inorganic compound layer to form a coating layer with a thickness of 0.3 μm (dry state) formed from an organic-inorganic mixture.

[0457] Then, water-based flexible inks are used on the coating layer to form an image using flexographic printing, thus forming a printed layer.

[0458] Next, a dry lamination adhesive (urethane-based adhesive) is applied to the surface of the substrate layer where the printed layer is formed. Then, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) serving as a sealant layer is adhered to the substrate layer through this adhesive layer.

[0459] Create the stacked body as shown above.

[0460] (3.1.2)Example 2C

[0461] Except for changing the thickness of the protective layer from 0.5 μm to 1 μm and thus eliminating the need for a coating layer, it is manufactured using the same method as in Example 1C. Figure 4 The laminate 10C shown.

[0462] (3.1.3) Example 3C

[0463] Except for changing the thickness of the protective layer from 0.5 μm to 3 μm, it was manufactured using the same method as in Example 1C. Figure 4 The laminate 10C shown.

[0464] (3.1.4)Example 4C

[0465] Except for the absence of a protective layer, it is manufactured using the same method as in Example 1C. Figure 4 The laminate 10C shown.

[0466] (3.1.5) Comparative Example 1C

[0467] Except for the following, it is manufactured using the same method as in Example 1C. Figure 4 The laminate 10C shown is an example of a laminate without a protective layer. Furthermore, instead of using the aforementioned polyethylene film with a crystallinity of 58.5%, a polyethylene film with a thickness of 25 μm, a crystallinity of 27.6%, and a haze of 21.5% is used as the substrate layer.

[0468] (3.2) Measurement and evaluation methods

[0469] Regarding the substrate layer used in the manufacture of the above-mentioned laminate, in-plane measurements were performed using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had sharp diffraction peaks corresponding to the (110) plane.

[0470] In addition, the sealing performance, heat resistance, visibility, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, visibility, and recyclability are described below.

[0471] (3.2.1) Evaluation method for sealing performance

[0472] The sealing performance was evaluated using the method described in (1.2.1).

[0473] (3.2.2) Evaluation method for heat resistance

[0474] Heat resistance was evaluated using the method described in (2.2.2).

[0475] (3.2.3) Methods for evaluating visibility

[0476] Visibility was evaluated using the methods described in (1.2.3).

[0477] (3.2.3) Evaluation method for recyclability

[0478] Recyclability is evaluated using the method described in (2.2.4).

[0479] (3.3) Results

[0480] The results of the above measurements and evaluations are shown in Table 3 below.

[0481]

[0482] As shown in Table 3, laminates with a substrate layer crystallinity of 35% or higher exhibit good recyclability, heat resistance, and visibility. Furthermore, laminates with a substrate layer crystallinity of 35% or higher and a protective layer also demonstrate excellent sealing performance. In contrast, laminates with a substrate layer crystallinity of less than 35% and no protective layer exhibit insufficient sealing performance, heat resistance, and visibility.

[0483] (4) Experiment D

[0484] (4.1) Fabrication of laminates

[0485] (4.1.1) Example 1D

[0486] Manufactured using the following methods Figure 5 The stacked body 10D is shown.

[0487] First, a substrate layer and intermediate layer are prepared with a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.94 g / cm³. 3 The polyethylene film. Furthermore, the degree of crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0488] Next, silicon oxide (SiO2) is formed on the intermediate layer as an inorganic compound layer with a thickness of 50 nm. x Evaporated film.

[0489] A first adhesive layer is formed by applying a dry lamination adhesive (urethane-based adhesive) onto a substrate layer. The substrate layer and the intermediate layer are then bonded together with the first adhesive layer sandwiched between them and the inorganic compound layer facing each other. Next, a printing layer is formed on the back side of the intermediate layer where the inorganic compound layer is formed.

[0490] Next, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) is prepared as a sealant layer. A dry lamination adhesive (urethane-based adhesive) is applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer are then bonded together with the second adhesive layer sandwiched in between and the sealant layer facing the printed layer.

[0491] Create the stacked body as shown above.

[0492] (4.1.2) Example 2D

[0493] Except for the adhesive used as the first and second adhesive layers, a gas-barrier polyamine adhesive is used instead of a urethane adhesive, and the adhesive is manufactured using the same method as in Example 1D. Figure 5 The stacked body 10D is shown.

[0494] (4.1.3) Example 3D

[0495] In addition to serving as the substrate layer, a film with a thickness of 25 μm, a crystallinity of 71.8%, a haze of 4.1%, and a density of 0.95 g / cm³ is used instead of the aforementioned polyethylene film with a crystallinity of 58.5%. 3 In addition to the polyethylene film, it is manufactured using the same method as in Example 1D. Figure 5 The laminate 10D shown is a longitudinally uniaxially stretched polyethylene film that has undergone one-sided corona treatment.

[0496] (4.1.4)Example 4D

[0497] Except for the following, it is manufactured using the same method as Example 1D. Figure 5 The laminate 10D shown is an example where, instead of the aforementioned polyethylene film with a crystallinity of 58.5%, a film with a thickness of 25 μm, a crystallinity of 55.9%, a haze of 5.9, and a density of 0.95 g / cm³ is used as the substrate layer. 3 The polyethylene film is a biaxially stretched film and undergoes single-sided corona treatment. Furthermore, instead of using the aforementioned polyethylene film with a crystallinity of 58.5%, a 25 μm thick film with a crystallinity of 71.8%, a haze of 4.1, and a density of 0.95 g / cm³ is used as the intermediate layer. 3 The high-density polyethylene film is a longitudinally uniaxially stretched film and has undergone single-sided corona treatment.

[0498] (4.1.5)Example 5D

[0499] In addition to serving as an intermediate layer, a film with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.95 g / cm³ is used instead of the aforementioned polyethylene film with a crystallinity of 58.5%. 3In addition to the polyethylene film, it is manufactured using the same method as in Example 1D. Figure 5 The laminate 10D shown is a polyethylene film that has undergone one-sided corona treatment.

[0500] (4.1.6)Example 6D

[0501] Except for the absence of a gas barrier layer, it is manufactured using the same method as Example 1D. Figure 5 The stacked body 10D is shown.

[0502] (4.1.7) Comparative Example 1D

[0503] In addition to serving as the substrate layer, a film with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm³ is used instead of the aforementioned polyethylene film with a crystallinity of 58.5%. 3 In addition to the polyethylene film, it is manufactured using the same method as in Example 1D. Figure 5 The laminate 10D shown is a polyethylene film that has undergone one-sided corona treatment.

[0504] (4.1.8) Comparative Example 2D

[0505] In addition to serving as the substrate layer and intermediate layer, a film with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm³ is used instead of the aforementioned polyethylene film with a crystallinity of 58.5%. 3 In addition to the polyethylene film, it is manufactured using the same method as in Example 1D. Figure 5 The laminate 10D shown is a polyethylene film that has undergone one-sided corona treatment.

[0506] (4.1.9) Comparative Example 3D

[0507] Except for the following, it is manufactured using the same method as Example 1D. Figure 5 The laminate 10D shown is an example where, instead of the aforementioned polyethylene film with a crystallinity of 58.5%, a film with a thickness of 25 μm, a crystallinity of 14.8%, a haze of 21.5%, and a density of 0.950 g / cm³ is used as the substrate layer. 3 The polyethylene film is subjected to one-sided corona treatment. Furthermore, no gas barrier layer is provided.

[0508] (4.2) Measurement and evaluation methods

[0509] Regarding the substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate, in-plane measurements were performed using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had sharp diffraction peaks corresponding to the (110) plane.

[0510] In addition, the sealing performance, heat resistance, visibility, puncture strength, and gas barrier properties of the aforementioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, visibility, puncture strength, and gas barrier properties are described below.

[0511] (4.2.1) Evaluation method for sealing performance

[0512] The sealing performance was evaluated using the method described in (2.2.1).

[0513] (4.2.2) Evaluation method for heat resistance

[0514] Heat resistance was evaluated using the method described in (1.2.2).

[0515] (4.2.3) Methods for evaluating visibility

[0516] Visibility was evaluated using the methods described in (1.2.3).

[0517] (4.2.4) Evaluation method of puncture intensity

[0518] A needle with a radius of 0.5 mm and a hemispherical tip is inserted into the laminate from the substrate layer side at a speed of 50 mm / min, and the maximum force until the needle penetrates is measured. This measurement is performed multiple times, and the arithmetic mean of the maximum forces is obtained as the puncture strength.

[0519] (4.2.5) Evaluation method for gas barrier properties

[0520] Gas barrier properties were evaluated using the method described in (1.2.4).

[0521] (4.3) Results

[0522] The results of the above measurements and evaluations are shown in Tables 4-1 and 4-2 below.

[0523]

[0524]

[0525] As shown in Tables 4-1 and 4-2, laminates with a substrate layer crystallinity of 35% or higher exhibit good sealing and heat resistance. Furthermore, laminates with both the substrate layer and intermediate layers having a crystallinity of 35% or higher also demonstrate excellent visibility and puncture strength. In contrast, laminates with a substrate layer crystallinity of less than 35% have insufficient sealing, heat resistance, and visibility.

[0526] (5) Experiment E

[0527] (5.1) Fabrication of laminates

[0528] (5.1.1)Example 1E

[0529] Manufactured using the following methods Figure 6 The laminate 10E is shown. In addition, in this example, an anchor coating is further provided between the intermediate layer 8 and the gas barrier layer 5, and an inorganic compound layer and a coating layer are provided as the gas barrier layer 5.

[0530] First, the anchoring agent, the coating liquid for forming the coating layer, and the coating liquid for forming the protective layer are prepared using the same method as in Example 1B. In this example, as in Example 1B, the same coating liquid is used to form the protective layer and the coating layer.

[0531] As the substrate layer and intermediate layer, a layer with a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.94 g / cm³ is prepared. 3 The polyethylene film. Furthermore, the degree of crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0532] Next, a corona treatment is applied to one side of the substrate layer. Then, the prepared protective layer forming coating liquid is applied to the corona-treated side of the substrate layer using a gravure coating method and dried to form a protective layer with a thickness of 0.5 μm formed of an organic-inorganic mixture.

[0533] Next, corona treatment is applied to the other side of the substrate layer. Then, water-based flexible ink is printed onto the corona-treated side of the substrate layer to form a printed layer.

[0534] A corona treatment was applied to the other side of the intermediate layer. Then, the anchoring agent was applied to the corona-treated side of the intermediate layer using a gravure coating method to form an anchoring coating with a thickness of 0.1 μm (dry state).

[0535] Next, using a vacuum evaporation apparatus with electron beam heating, silicon oxide (SiO2) was formed on the anchor coating as an inorganic compound layer to a thickness of 40 nm. x Next, the coating liquid for forming the above-prepared coating layer is applied onto the inorganic compound layer to form a coating layer with a thickness of 0.3 μm (dry state) formed from an organic-inorganic mixture.

[0536] Next, a dry lamination adhesive (urethane-based adhesive) is applied to the side of the intermediate layer opposite to the side where the inorganic compound layer is formed to form a first adhesive layer. The substrate layer and the intermediate layer are then bonded together with the first adhesive layer sandwiched in between and the printed layer facing each other.

[0537] Next, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) is prepared as a sealant layer. A dry lamination adhesive (urethane-based adhesive) is applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer are then bonded together with the second adhesive layer sandwiched in between and the sealant layer facing each other.

[0538] Create the stacked body as shown above.

[0539] (5.1.2)Example 2E

[0540] Except for the following, it is manufactured using the same method as Example 1E. Figure 6 The laminate 10E shown is an example where, instead of the aforementioned polyethylene film with a crystallinity of 58.5%, a film with a thickness of 25 μm, a crystallinity of 55.9%, a haze of 5.9%, and a density of 0.95 g / cm³ is used as the substrate layer and intermediate layer. 3 The polyethylene film was subjected to one-sided corona treatment.

[0541] (5.1.3) Example 3E

[0542] Except for the following, it is manufactured using the same method as Example 2E. Figure 6 The laminate 10E shown is an example of a film without a protective layer. Furthermore, instead of the aforementioned polyethylene film with a crystallinity of 55.9%, an intermediate layer is used with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm³. 3 The polyethylene film was subjected to one-sided corona treatment.

[0543] (5.1.4) Comparative Example 1E

[0544] Except for the following, it is manufactured using the same method as Example 1E. Figure 6 The laminate 10E shown is an example of a laminate without a protective layer. Furthermore, instead of the aforementioned polyethylene film with a crystallinity of 58.5%, a film with a thickness of 25 μm, a crystallinity of 27.5%, a haze of 21.5%, and a density of 0.950 g / cm³ is used as the substrate layer and intermediate layer. 3 The polyethylene film was subjected to one-sided corona treatment.

[0545] (5.2) Measurement and evaluation methods

[0546] Regarding the substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate, in-plane measurements were performed using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had sharp diffraction peaks corresponding to the (110) plane.

[0547] In addition, the sealing performance, heat resistance, visibility, puncture strength, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, visibility, puncture strength, and recyclability are described below.

[0548] (5.2.1) Evaluation method for sealing performance

[0549] The sealing performance (heat resistance) was evaluated using the method described in (2.2.1).

[0550] (5.2.2) Evaluation method for heat resistance

[0551] Heat resistance was evaluated using the method described in (2.2.2).

[0552] (5.2.3) Methods for evaluating visibility

[0553] Visibility was evaluated using the methods described in (1.2.3).

[0554] (5.2.4) Evaluation method of puncture intensity

[0555] The puncture strength was evaluated using the method described in (4.2.4).

[0556] (5.2.5) Evaluation method for recyclability

[0557] Recyclability is evaluated using the method described in (2.2.4).

[0558] (5.3) Results

[0559] The results of the above measurements and evaluations are shown in Table 5 below.

[0560] Table 5

[0561]

[0562] As shown in Table 5, laminates with a substrate layer crystallinity of 35% or higher exhibit good heat resistance, visibility, and puncture strength. Furthermore, laminates with a substrate layer and intermediate layer crystallinity of 35% or higher and a protective layer also demonstrate excellent sealing performance and further improved puncture strength. Conversely, laminates with a substrate layer crystallinity of less than 35% and lacking a protective layer exhibit insufficient sealing performance, heat resistance, visibility, and puncture strength.

[0563] (6) Experiment F

[0564] (6.1) Fabrication of laminates

[0565] (6.1.1)Example 1F

[0566] Manufactured using the following methods Figure 7 The laminate 10F is shown. In addition, in this example, an anchor coating is further provided between the intermediate layer 8 and the gas barrier layer 5, and an inorganic compound layer and a coating layer are provided as the gas barrier layer 5.

[0567] First, the anchoring agent, the coating liquid for forming the coating layer, and the coating liquid for forming the protective layer are prepared using the same method as in Example 1B. In this example, as in Example 1B, the same coating liquid is used to form the protective layer and the coating layer.

[0568] As the substrate layer, a layer with a thickness of 25 μm, a crystallinity of 58.5%, and a density of 0.950 g / cm³ was prepared. 3 The polyethylene film was subjected to one-sided corona treatment. Furthermore, the degree of crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0569] Next, a corona treatment is applied to one side of the substrate layer. Then, the prepared protective layer forming coating liquid is applied to the corona-treated side of the substrate layer using a gravure coating method and dried to form a protective layer with a thickness of 0.5 μm formed of an organic-inorganic mixture.

[0570] Next, corona treatment is applied to the other side of the substrate layer. Then, water-based flexible ink is printed onto the corona-treated side of the substrate layer to form a printed layer.

[0571] Next, an intermediate layer with a thickness of 25 μm, a crystallinity of 27.5%, and a density of 0.950 g / cm³ was prepared. 3 The polyethylene film was subjected to one-sided corona treatment.

[0572] The above-mentioned anchoring agent was applied using a gravure coating method to form an anchoring coating with a thickness of 0.1 μm (dry state).

[0573] Next, silicon oxide (SiO2) is formed on the anchor coating as an inorganic compound layer with a thickness of 40 nm. x Next, the above-prepared coating solution is applied to the inorganic compound layer to form a coating layer with a thickness of 0.3 μm (dry state) formed from an organic-inorganic mixture.

[0574] Next, a dry lamination adhesive (urethane-based adhesive) is applied to the side of the intermediate layer opposite to the side where the inorganic compound layer is formed to form a first adhesive layer. The substrate layer and the intermediate layer are then bonded together with the first adhesive layer sandwiched in between and the printed layer facing each other.

[0575] Next, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) is prepared as a sealant layer. A dry lamination adhesive (urethane-based adhesive) is applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer are then bonded together with the second adhesive layer sandwiched in between and the sealant layer facing each other.

[0576] Create the stacked body as shown above.

[0577] (6.1.2)Example 2F

[0578] Except for the following, it is manufactured using the same method as in Example 1F. Figure 7 The laminate 10F shown is an example where, instead of the aforementioned polyethylene film with a crystallinity of 58.5%, a film with a thickness of 25 μm, a crystallinity of 55.9%, a haze of 21.5%, and a density of 0.95 g / cm³ is used as the substrate layer. 3 The polyethylene film was subjected to one-sided corona treatment.

[0579] (6.1.3)Example 3F

[0580] Except for the following, it is manufactured using the same method as in Example 1F. Figure 7 The laminate 10F shown is an example of a model where no protective layer is provided. Furthermore, instead of using the aforementioned polyethylene film with a crystallinity of 58.5% as the substrate layer, and instead of using the aforementioned polyethylene film with a crystallinity of 27.5% as the intermediate layer, a film with a thickness of 25 μm, a crystallinity of 55.9%, and a density of 0.95 g / cm³ is used. 3 The polyethylene film was subjected to one-sided corona treatment.

[0581] (6.1.4) Comparative Example 1F

[0582] Except for the following, it is manufactured using the same method as in Example 1F. Figure 7 The laminate 10F shown is an example of a laminate without a protective layer. Furthermore, instead of the aforementioned polyethylene film with a crystallinity of 58.5%, a film with a thickness of 25 μm, a crystallinity of 27.5%, and a density of 0.950 g / cm³ is used as the substrate layer. 3 A polyethylene film was used. This polyethylene film underwent single-sided corona treatment. Furthermore, instead of using the aforementioned polyethylene film with a crystallinity of 27.5%, a film with a thickness of 25 μm, a crystallinity of 55.9%, and a density of 0.95 g / cm³ was used as the intermediate layer. 3 The polyethylene film was subjected to one-sided corona treatment.

[0583] (6.2) Measurement and evaluation methods

[0584] Regarding the substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate, in-plane measurements were performed using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had sharp diffraction peaks corresponding to the (110) plane.

[0585] In addition, the sealing performance, heat resistance, drop strength, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, drop strength, and recyclability are described below.

[0586] (6.2.1) Evaluation method for sealing performance

[0587] The sealing performance was evaluated using the method described in (2.2.1).

[0588] (6.2.2) Evaluation method for heat resistance

[0589] Heat resistance was evaluated using the method described in (2.2.2).

[0590] (6.2.3) Evaluation method for drop intensity

[0591] The laminated body was cut to a specified size, and the edges were heat-sealed to produce 10 bags. Each bag had an opening for placing the contents. The bags measured 100mm x 150mm. Next, 200mL of tap water was filled into each bag, and the opening was heat-sealed to obtain packaged items. Each packaged item was then stored at 5°C for one day, followed by 50 drops from a height of 1.5m. The drop strength was calculated as the ratio of the number of packaged items that broke within 50 drops to the total number of packaged items (10 bags).

[0592] (6.2.4) Evaluation method for recyclability

[0593] Recyclability is evaluated using the method described in (2.2.4).

[0594] (6.3) Results

[0595] The results of the above measurements and evaluations are shown in Table 6 below.

[0596] Table 6

[0597]

[0598] As shown in Table 6, laminates with a substrate layer crystallinity of 35% or higher exhibit good recyclability and heat resistance. Furthermore, laminates with a substrate layer crystallinity of 35% or higher, an intermediate layer crystallinity of less than 35%, and a protective layer also demonstrate excellent sealing and drop strength. However, laminates with a substrate layer crystallinity of less than 35% and lacking a protective layer exhibit insufficient sealing, heat resistance, and drop strength.

[0599] (7) Test G

[0600] (7.1) Fabrication of laminates

[0601] (7.1.1) Example 1G

[0602] Manufactured using the following methods Figure 8 The laminate 10G is shown. Furthermore, in this example, an anchor coating is further provided between the intermediate layer 8 and the inorganic compound layer 5.

[0603] First, the coating liquid for anchoring agent formation and the coating liquid for coating layer formation are prepared using the same method as in Example 1B.

[0604] In addition, an organic solvent solution of polyamide-imide resin (with a non-volatile component concentration of 5% by mass) is prepared as a coating liquid for forming a protective layer.

[0605] As the substrate layer and intermediate layer, a layer with a thickness of 25 μm, a crystallinity of 58.5%, a haze of 1.6%, and a density of 0.950 g / cm³ is prepared. 3 The polyethylene film is a three-layer structure (HDPE / MDPE / HDPE) and undergoes double-sided corona treatment. Furthermore, the degree of crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0606] Next, the protective layer forming liquid prepared above was applied to one side of the substrate layer that had undergone corona treatment using a gravure coating method and dried to form a protective layer with a thickness of 0.5 μm. Then, water-based flexible ink was printed onto the other side of the substrate layer that had undergone corona treatment to form a printed layer.

[0607] Next, the anchoring agent was applied to one side of the intermediate layer that had undergone corona treatment using a gravure coating method to form an anchoring coating with a thickness of 0.1 μm (dry state).

[0608] Next, as an inorganic compound layer, transparent silicon oxide (SiO2) is formed on the anchor coating to a thickness of 40 nm using a vacuum evaporation apparatus employing electron beam heating. x Evaporated film. The O / Si ratio of the evaporated film is achieved to 1.8 by adjusting the types of materials used in the evaporation process.

[0609] Next, the coating liquid for forming the above-prepared coating layer is applied onto the inorganic compound layer to form a coating layer with a thickness of 0.3 μm (dry state) formed from an organic-inorganic mixture.

[0610] Next, a dry lamination adhesive (urethane-based adhesive) is applied to the side of the intermediate layer opposite to the side where the inorganic compound layer is formed to form a first adhesive layer. The substrate layer and the intermediate layer are then bonded together with the first adhesive layer sandwiched in between and the printed layer facing each other.

[0611] Next, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) is prepared as a sealant layer. A dry lamination adhesive (urethane-based adhesive) is applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer are then bonded together with the second adhesive layer sandwiched in between and the sealant layer facing each other.

[0612] Create the stacked body as shown above.

[0613] (7.1.2) Example 2G

[0614] Except for changing the protective layer thickness from 0.5 μm to 1 μm, it was manufactured using the same method as in Example 1G. Figure 8 The stack shown is 10G.

[0615] (7.1.3) Example 3G

[0616] Except for changing the protective layer thickness from 0.5 μm to 3 μm, it was manufactured using the same method as in Example 1G. Figure 8 The stack shown is 10G.

[0617] (7.1.4) Example 4G

[0618] Except for the following, it is manufactured using the same method as Example 1G. Figure 8 The laminate 10G shown is an example of a laminate without a protective layer. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5%, a polyethylene film with a thickness of 25 μm, a crystallinity of 27.6%, and a haze of 21.5% is used as the intermediate layer.

[0619] (7.1.5) Comparative Example 1G

[0620] Except for the following, it is manufactured using the same method as Example 1G. Figure 8 The laminate shown is 10G. That is, no protective layer is provided. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5%, a polyethylene film with a thickness of 25 μm and a crystallinity of 27.6% is used as the substrate layer and intermediate layer.

[0621] (7.2) Measurement and evaluation methods

[0622] Regarding the substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate, in-plane measurements were performed using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had sharp diffraction peaks corresponding to the (110) plane.

[0623] In addition, the sealing performance, heat resistance, visibility, puncture strength, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, visibility, puncture strength, and recyclability are described below.

[0624] (7.2.1) Evaluation method for sealing performance

[0625] The sealing performance is evaluated using the method described in (1.2.1).

[0626] (7.2.2) Evaluation method for heat resistance

[0627] Heat resistance is evaluated using the methods described in (2.2.2).

[0628] (7.2.3) Methods for evaluating visibility

[0629] Visibility is evaluated using the methods described in (1.2.3).

[0630] (7.2.4) Evaluation method of puncture intensity

[0631] The puncture strength was evaluated using the method described in (4.2.4).

[0632] (7.2.5) Evaluation method for recyclability

[0633] The evaluation shall be conducted using the methods described in (2.2.4) on recycling and regeneration.

[0634] (7.3) Results

[0635] The results of the above measurements and evaluations are shown in Table 7 below.

[0636] Table 7

[0637]

[0638] As shown in Table 7, laminates with a substrate layer crystallinity of 35% or higher exhibit good recyclability, heat resistance, and visibility. Furthermore, laminates with a substrate layer and intermediate layer crystallinity of 35% or higher and a protective layer also demonstrate excellent sealing and puncture strength. Conversely, laminates with a substrate layer crystallinity of less than 35% and lacking a protective layer exhibit insufficient sealing, heat resistance, visibility, and puncture strength.

[0639] (8) Test G

[0640] (8.1) Fabrication of laminates

[0641] (8.1.1)Example 1H

[0642] Manufactured using the following methods Figure 9 The laminate 10H is shown. Furthermore, in this example, an anchor coating is further provided between the intermediate layer 8 and the inorganic compound layer 5.

[0643] First, the coating liquid for anchoring agent formation and the coating liquid for coating layer formation are prepared using the same method as in Example 1B.

[0644] In addition, an organic solvent solution of polyamide-imide resin (with a non-volatile component concentration of 5% by mass) is prepared as a coating liquid for forming a protective layer.

[0645] As the substrate layer, a polyethylene film with a thickness of 25 μm, a crystallinity of 58.5%, and a haze of 1.6% was prepared. This polyethylene film underwent double-sided corona treatment. Furthermore, the crystallinity shown in this example and the examples and comparative examples described below was determined using the above-described method.

[0646] Next, the protective layer forming liquid prepared above was applied to one side of the substrate layer that had undergone corona treatment using a gravure coating method and dried to form a protective layer with a thickness of 0.5 μm. Then, water-based flexible ink was printed onto the other side of the substrate layer that had undergone corona treatment to form a printed layer.

[0647] As an intermediate layer, a polyethylene film with a thickness of 25 μm, a crystallinity of 27.6%, and a haze of 21.5% was prepared. This polyethylene film underwent double-sided corona treatment. Next, the aforementioned anchoring agent was applied to the corona-treated side of the intermediate layer using a gravure coating method to form an anchoring coating with a thickness of 0.1 μm (dry state).

[0648] Next, as an inorganic compound layer, transparent silicon oxide (SiO2) is formed on the anchor coating to a thickness of 40 nm using a vacuum evaporation apparatus employing electron beam heating. x Evaporated film. The O / Si ratio of the evaporated film is achieved to 1.8 by adjusting the types of materials used in the evaporation process.

[0649] Next, the coating liquid for forming the above-prepared coating layer is applied to the inorganic compound layer to form a coating layer with a thickness of 0.3 μm (dry state) formed by an organic-inorganic mixture.

[0650] Next, a dry lamination adhesive (urethane-based adhesive) is applied to the side of the intermediate layer opposite to the side where the inorganic compound layer is formed to form a first adhesive layer. The substrate layer and the intermediate layer are then bonded together with the first adhesive layer sandwiched in between and the printed layer facing each other.

[0651] Next, a linear low-density polyethylene resin (LLDPE) film (60 μm thick) is prepared as a sealant layer. A dry lamination adhesive (urethane-based adhesive) is applied to the sealant layer to form a second adhesive layer. The substrate layer and the sealant layer are then bonded together with the second adhesive layer sandwiched in between and the sealant layer facing each other.

[0652] Create the stacked body as shown above.

[0653] (8.1.2) Example 2H

[0654] Except for changing the protective layer thickness from 0.5 μm to 1 μm and thus eliminating the coating layer, it was manufactured using the same method as in Example 1H. Figure 9 The laminate shown is 10H.

[0655] (8.1.3) Example 3H

[0656] Except for changing the protective layer thickness from 0.5 μm to 3 μm, it was manufactured using the same method as in Example 1H. Figure 9 The laminate shown is 10H.

[0657] (8.1.4)Example 4H

[0658] Except for the following, it is manufactured using the same method as in Example 1H. Figure 9 The laminate 10H shown is an example of a polyethylene film without a protective layer. Furthermore, instead of using the aforementioned polyethylene film with a crystallinity of 27.6%, a polyethylene film with a thickness of 25 μm, a crystallinity of 58.5%, and a haze of 1.6% is used as the intermediate layer. This polyethylene film undergoes double-sided corona treatment.

[0659] (8.1.5) Comparative Example 1H

[0660] Except for the following, it is manufactured using the same method as in Example 1H. Figure 9 The laminate 10H shown is an example of a polyethylene film without a protective layer. Furthermore, instead of using the polyethylene film with a crystallinity of 58.5%, a polyethylene film with a thickness of 25 μm, a crystallinity of 27.6%, and a haze of 21.5% is used as the substrate layer. This polyethylene film undergoes double-sided corona treatment. Similarly, instead of using the polyethylene film with a crystallinity of 27.6%, a polyethylene film with a thickness of 25 μm, a crystallinity of 58.5%, and a haze of 1.6% is used as the intermediate layer. This polyethylene film also undergoes double-sided corona treatment.

[0661] (8.2) Measurement and evaluation methods

[0662] Regarding the substrate layer and intermediate layer used in the manufacture of the above-mentioned laminate, in-plane measurements were performed using the wide-angle X-ray diffraction method described above. Furthermore, it was investigated whether the diffraction pattern obtained by this measurement had sharp diffraction peaks corresponding to the (110) plane.

[0663] In addition, the sealing performance, heat resistance, visibility, drop strength, and recyclability of the above-mentioned laminates were evaluated. The evaluation methods for sealing performance, heat resistance, visibility, drop strength, and recyclability are described below.

[0664] (8.2.1) Evaluation method for sealing performance

[0665] The sealing performance is evaluated using the method described in (1.2.1).

[0666] (8.2.2) Methods for evaluating visibility

[0667] Visibility is evaluated using the methods described in (1.2.2).

[0668] (8.2.3) Evaluation method for drop intensity

[0669] Drop strength is evaluated using the method described in (6.2.3).

[0670] (8.2.4) Evaluation method for recyclability

[0671] The evaluation shall be conducted using the methods described in (2.2.4) on recycling and regeneration.

[0672] (8.3) Results

[0673] The results of the above measurements and evaluations are shown in Table 8 below.

[0674] Table 8

[0675]

[0676] As shown in Table 8, laminates with a substrate layer crystallinity of 35% or higher exhibit good recyclability, heat resistance, and visibility. Furthermore, laminates with a substrate layer crystallinity of 35% or higher, an intermediate layer crystallinity of less than 35%, and a protective layer also demonstrate excellent sealing and drop strength. However, laminates with a substrate layer crystallinity of less than 35% and lacking a protective layer exhibit insufficient sealing, heat resistance, and visibility.

[0677] Symbol Explanation

[0678] 1. Substrate layer, 2. Sealant layer, 3. Adhesive layer, 3A. First adhesive layer, 3B. Second adhesive layer, 4. Printing layer, 5. Gas barrier layer (inorganic compound layer), 6. Protective layer, 7. Coating layer, 8. Intermediate layer, 10A1 laminate, 10A2 laminate, 10B laminate, 10C laminate, 10D laminate, 10E laminate, 10F laminate, 10G laminate, 10H laminate, 100A packaged goods, 100B packaged goods, 100C packaged goods, 110A package body, 110B package body, 110C package body, 110C1 container body, 110C2 opening component, 110C3 cap.

Claims

1. A laminate comprising, sequentially, a substrate layer, an adhesive layer, and a sealant layer, The substrate layer and the sealant layer comprise polyethylene. The sealant layer is an unstretched layer. The degree of crystallinity of the substrate layer, measured by the parallel beam method of X-ray diffraction within a diffraction angle range of 10° to 30°, is 35% or more and 75% or less, which is the ratio of the crystallization peak area to the total peak area.

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

3. The laminated body according to claim 2, wherein, The degree of crystallinity of the intermediate layer, measured by the parallel beam method of X-ray diffraction within a diffraction angle range of 10° to 30°, is 35% or higher, which is the ratio of the crystallization peak area to the total peak area.

4. The laminate according to claim 2, wherein, The crystallinity of the intermediate layer, measured by the parallel beam method of X-ray diffraction within a diffraction angle range of 10° to 30°, is less than 35% as the ratio of the crystallization peak area to the total peak area.

5. The laminate according to claim 1, further comprising a protective layer with the substrate layer sandwiched in the middle, serving as the outermost layer facing the sealant layer.

6. The laminate according to claim 5, wherein, The protective layer comprises a thermosetting resin.

7. The laminated body according to claim 1, wherein, The substrate layer is a biaxially stretched film.

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

9. The laminate according to claim 1, further comprising a gas barrier layer between the substrate layer and the sealant layer.

10. The laminate according to claim 1, wherein, The adhesive layer is gas-barrier.

11. The laminate according to claim 1, wherein, The sealant layer is white.

12. The laminate according to claim 1, wherein, Polyethylene accounts for more than 90% by mass in the laminate.

13. The laminate according to any one of claims 2 to 4, wherein, The adhesive layer comprises a first adhesive layer and a second adhesive layer, wherein the first adhesive layer exists between the substrate layer and the intermediate layer, and the second adhesive layer exists between the intermediate layer and the sealant layer.

14. A packaging body comprising the laminate of any one of claims 1 to 13.

15. The packaging body according to claim 14, wherein it is a stand-up pouch.

16. A packaged article comprising the package body as described in claim 14 or 15 and contents contained therein.

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