Laminate, package, and packaged article

Abstract

Provided is a laminate mainly comprising a polyethylene and having excellent heat resistance. A laminate (10A) has a substrate layer (2), an adhesive layer (5), and a sealant layer (6) in this order, wherein: the substrate layer (2) and the sealant layer (6) include a polyethylene; and the absolute value of the degree of molecular orientation of the substrate layer (2) as measured by the microwave method is at least 1.07.

Description

Laminate, packaging body and packaged article

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

[0002] Packaging materials used in packaging bags and the like are required to have various properties depending on the application. Examples of required properties include heat resistance, transparency, strength, gas barrier properties, bag-making suitability, printability, transport suitability, etc. In order to fully satisfy each of these various performance requirements, it has been common practice to combine multiple types of synthetic resin films with different properties.

[0003] For example, a resin film made of polyethylene is inferior in strength and heat resistance and therefore cannot be used alone as a base material for packaging materials, and is therefore used in combination with a resin film made of polyester, polyamide, or the like.

[0004] In recent years, with the growing demand for the creation of a recycling-oriented society, there has been a demand for packaging materials with high recyclability. Generally, packaging materials containing 90% or more by mass of the main resin are considered to have high recyclability. However, as described above, conventional packaging materials are composed of different resin materials, and since it is difficult to separate the resin materials after use, they cannot be recycled as individual materials. Therefore, even if packages formed using conventional packaging materials are recovered, the only option is to burn them and recover and reuse them as heat, which is currently incompatible with the recent trend toward protecting the global environment.

[0005] When using packaging materials made of polyethylene resin to achieve high recyclability, the following specific problems arise. Specifically, the bag-making process for forming packaging bags typically involves a heat-sealing step in which the sealant layers of a laminate are joined together and then pressed against a high-temperature jig from the outer surface of the base layer of the laminate, thereby sandwiching the laminate between the two layers. The jig used in the heat-sealing machine is heated to a high temperature, and the outer surface of the base layer that directly contacts the jig is exposed to high temperatures. When a base layer made of polyethylene resin, which has poor heat resistance, is affected by heat, the heat-sealed portion can be thermally damaged, resulting in poor appearance such as thermal shrinkage and distortion, or problems such as resin adhesion to the jig. To avoid this problem, narrowing the bag-making conditions by slowing the bag-making speed or adjusting the bag-making temperature (heat-sealing temperature) to reduce heat damage results in reduced productivity.

[0006] Patent Document 1 proposes a technology for making a packaging film have as simple a layer structure as possible from the viewpoint of recycling. Specifically, focusing on the problems with polyethylene single-layer films in terms of blocking resistance and openability (ease of opening) when used in a package, the document proposes a packaging film having, on a polyethylene-containing substrate layer, a resin-containing coating layer whose glass transition temperature satisfies specific conditions relative to the polyethylene-containing substrate, in order to improve these problems.

[0007] However, this does not take into consideration the fact that polyethylene resin has poor heat resistance, and does not solve the above-mentioned problem regarding heat resistance in packaging materials containing polyethylene resin as the main material.

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

[0009] An object of the present invention is to provide a laminate which is mainly made of polyethylene and has excellent heat resistance.

[0010] According to one aspect of the present invention, there is provided a laminate comprising a substrate layer, an adhesive layer, and a sealant layer in this order, wherein the substrate layer and the sealant layer contain polyethylene, and the substrate layer has an absolute value of a degree of molecular orientation measured by a microwave method of 1.07 or more.

[0011] According to another aspect of the present invention, there is provided a laminate according to the above aspect, further comprising an intermediate layer containing polyethylene and interposed between the base layer and the sealant layer.

[0012] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the intermediate layer has a degree of molecular orientation of 1.07 or less in absolute value as measured by a microwave method.

[0013] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the intermediate layer has a degree of molecular orientation of 1.07 or more in absolute value as measured by a microwave method.

[0014] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, further comprising a protective layer as an outermost layer facing the sealant layer with the base layer sandwiched therebetween.

[0015] According to yet another aspect of the present invention, there is provided the laminate according to the above aspect, wherein the protective layer is made of a thermosetting resin.

[0016] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the substrate layer is a biaxially stretched film.

[0017] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the base layer is a uniaxially stretched film.

[0018] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, further comprising a gas barrier layer interposed between the base layer and the sealant layer.

[0019] According to yet another aspect of the present invention, there is provided the laminate according to any one of the above aspects, wherein the adhesive layer has gas barrier properties.

[0020] According to yet another aspect of the present invention, there is provided a laminate according to any of the above aspects, wherein the sealant layer is white.

[0021] According to yet another aspect of the present invention, there is provided a laminate according to any one of the above aspects, in which the proportion of polyethylene is 90% by mass or more.

[0022] According to yet another aspect of the present invention, there is provided a package including a laminate according to any of the above aspects.

[0023] According to yet another aspect of the present invention, there is provided a package according to the above aspect, which is a stand-up pouch.

[0024] According to yet another aspect of the present invention, there is provided a packaged article including a package according to any of the above aspects and contents contained therein.

[0025] According to the present invention, a laminate mainly made of polyethylene and having excellent heat resistance is provided.

[0026] Fig. 1 is a cross-sectional view schematically showing a laminate according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view schematically showing a laminate according to a second embodiment of the present invention. Fig. 3 is a cross-sectional view schematically showing a laminate according to a third embodiment of the present invention. Fig. 4 is a cross-sectional view schematically showing a laminate according to a fourth embodiment of the present invention. Fig. 5 is a cross-sectional view schematically showing a laminate according to a fifth embodiment of the present invention. Fig. 6 is a cross-sectional view schematically showing a laminate according to a sixth embodiment of the present invention. Fig. 7 is a view schematically showing a packaging article according to a seventh embodiment of the present invention. Fig. 8 is a view schematically showing a packaging article according to an eighth embodiment of the present invention. Fig. 9 is a view schematically showing a packaging article according to a ninth embodiment of the present invention.

[0027] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific embodiments of any of the above aspects. The following items can be incorporated into each of the above aspects, either singly or in combination.

[0028] Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited by the materials, shapes, structures, etc. of the components described below. Various modifications can be made to the technical idea of ​​the present invention within the technical scope defined by the claims.

[0029] In addition, elements having the same or similar functions are assigned the same reference numerals in the drawings referred to below, and duplicated descriptions will be omitted. Therefore, matters referred to in one embodiment can also be applied to other embodiments unless otherwise specified. Furthermore, the drawings are schematic, and the relationship between dimensions in one direction and dimensions in another direction, and the relationship between the dimensions of one member and the dimensions of another member, etc. may differ from the actual ones.

[0030] In this disclosure, the expression "AA on BB" is used regardless of the direction of gravity. The state specified by the expression "AA on BB" includes a state in which AA is in contact with BB. The expression "AA on BB" does not exclude the presence of one or more other components between AA and BB.

[0031] <1> First embodiment <1.1> Laminate Fig. 1 is a cross-sectional view schematically showing a laminate according to a first embodiment of the present invention. The laminate 10A shown in Fig. 1 includes a base layer 2, a gas barrier layer 3, a printing layer 4, an adhesive layer 5, and a sealant layer 6, in this order.

[0032] The laminate 10A has a polyethylene content of 90% by mass or more. Here, the polyethylene content in the laminate 10A refers to the proportion of the total amount of polyethylene to the total amount of resin material in each layer constituting the laminate 10A. By making the polyethylene content 90% by mass or more, high recyclability can be achieved.

[0033] Each layer included in the laminate 10A will be described below.

[0034] <1.2> Base Material Layer The base material layer 2 contains polyethylene. The polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and another monomer. When the polyethylene is a copolymer of ethylene and another monomer, the proportion of ethylene in the copolymer is, for example, 80 mol % or more.

[0035] The other monomer is, for example, an α-olefin. According to one example, the α-olefin has a carbon number in the range of 3 to 20. Such an α-olefin is, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, or 6-methyl-1-heptene.

[0036] The polyethylene may be a copolymer of ethylene and one of vinyl acetate and acrylic esters.

[0037] The base material layer 2 is, for example, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very-low-density polyethylene (VLDPE). Among these, high-density polyethylene and medium-density polyethylene are preferred from the viewpoints of printability, strength, and heat resistance of the laminate 10A and stretchability of the film, and medium-density polyethylene is more preferred from the viewpoint of stretchability.

[0038] Here, high density polyethylene has a density of 0.942 g / cm ３ or more, and medium density polyethylene has a density of 0.930 g / cm ３ 0.942g / cm or more ３ and low density polyethylene has a density of 0.910 g / cm ３ 0.930g / cm or more ３ and linear low density polyethylene has a density of 0.910 g / cm ３ Over 0.930cm ３ and ultra-low density polyethylene has a density of 0.910 g / cm ３ The density is a value obtained by a method in accordance with JIS K7112:1999.

[0039] The polyethylene contained in the base material layer 2 may be a biomass-derived polyethylene. As the biomass-derived polyethylene, for example, Green Polyethylene (manufactured by Braskem) can be used.

[0040] Alternatively, the polyethylene contained in the base layer 2 may be polyethylene recycled by mechanical recycling. Here, mechanical recycling refers to decontaminating the polyethylene film by crushing recovered polyethylene film, etc., then washing the crushed film with an alkali to remove dirt and foreign matter from the film surface, and drying the film at high temperature and reduced pressure to diffuse contaminants remaining inside the film. Alternatively, the polyethylene contained in the base layer 2 may be polyethylene recycled by chemical recycling.

[0041] The substrate layer 2 has an absolute value of the molecular orientation (i.e., Microwave Orientation Ratio; MOR) measured by a microwave method of 1.07 or more. The absolute value of the molecular orientation measured by a microwave method is also simply referred to as the "molecular orientation" in this specification. The molecular orientation is an index that represents the degree to which molecular chains are oriented in a uniform manner. In other words, a high molecular orientation means that the molecular chains are oriented in a uniform manner. A layer having a molecular orientation of 1.07 or more has excellent heat resistance, and in films with a high molecular orientation, the spherulite size is small, so that excellent transparency and sufficient visibility can be ensured. Furthermore, by increasing the molecular orientation, it is possible to impart toughness to the film, thereby improving impact resistance and puncture resistance.

[0042] The degree of molecular orientation of the substrate layer 2 is preferably 1.10 or more, more preferably 1.15 or more, even more preferably 1.20 or more, even more preferably 1.25 or more, and even more preferably 1.30 or more. Increasing the degree of molecular orientation of the substrate layer 2 can further improve the above-mentioned effects. The upper limit of the degree of molecular orientation of the substrate layer 2 is not particularly limited, but is, for example, 2.0 or less, 1.8 or less, or 1.5 or less.

[0043] The degree of molecular orientation of the base layer 2 can be adjusted by changing factors such as the density of the resin (particularly polyethylene) used in the base layer 2, the type of comonomer, molecular weight, molecular weight distribution, and manufacturing method, in addition to the stretching conditions such as the stretch ratio in each of the MD (machine direction) and TD (transverse direction). The rheological properties of the molten resin when stretching the resin film are also factors that affect the degree of molecular orientation. Even when stretching is performed at the same stretch ratio, the degree of molecular orientation can be adjusted by changing the various factors mentioned above. The degree of molecular orientation can also be adjusted by applying shear stress to the molten resin during the film formation stage.

[0044] The degree of molecular orientation is measured by a microwave method as described above. That is, the degree of molecular orientation is measured by a perturbation method using a microwave cavity resonator. Specifically, the degree of molecular orientation can be measured using a microwave molecular orientation meter such as the Molecular Orientation Meter MOA-5012A (manufactured by Oji Scientific Instruments Co., Ltd.). A microwave molecular orientation meter rotates a sheet-like sample in a microwave polarized electric field and measures the orientation of molecular chains in the sheet from the interaction between the microwave electric field and the dipoles that make up the polymeric substance.

[0045] When measuring the degree of molecular orientation using a microwave molecular orientation meter, for example, a sample having a square shape with a side length of 35 mm and a thickness of 2 mm or less is used, and the measurement frequency is set within the range of 12.0 GHz to 13.0 GHz.

[0046] Preferably, the degree of molecular orientation is measured at each of a plurality of locations on the base material layer 2, and the average value of the obtained molecular orientation degrees is taken as the degree of molecular orientation of the base material layer 2. The plurality of locations on the base material layer 2 are, for example, the central portion and end portions of the base material layer 2.

[0047] The substrate layer 2 is preferably a stretched film. When the substrate layer 2 is a stretched film, the substrate layer 2 may be a uniaxially stretched film or a biaxially stretched film. In this specification, the term "film" does not include the concept of thickness.

[0048] When a uniaxially stretched film is used as the base layer 2, heat resistance during bag production is improved. When a biaxially stretched film is used as the base layer 2, drop strength of a packaged article using the laminate 10A as a packaging material is improved.

[0049] Whether a stretched film is a uniaxially stretched film or a biaxially stretched film can be determined by performing in-plane measurement using wide-angle X-ray diffraction, as described below. The X-ray diffraction pattern obtained by this measurement contains information about the degree of orientation of molecular chains present in the film plane. An example of the measurement method is shown below.

[0050] First, an out-of-plane measurement is performed using a wide-angle X-ray diffractometer manufactured by Rigaku Corporation using the parallel beam method. The X-ray diffraction pattern of the film to be measured is obtained by 2θ / θ scanning in the diffraction angle range of 10° to 30°. α X-rays are used, and the X-rays are collimated by a multilayer mirror and made incident on the base material layer 1. A scintillation detector equipped with a flat collimator is used as the light receiving unit.

[0051] From the obtained X-ray diffraction pattern, the peak area of ​​the crystalline component and the halo pattern area of ​​the amorphous component are determined, and the ratio of the peak area of ​​the crystalline component to the total area is calculated as the crystallinity. When the film to be measured has multiple layers, the crystallinity of one of the outermost surfaces of the film is measured.

[0052] When the film to be measured is a polyethylene film, scanning at a diffraction angle range of 10° to 30° reveals two sharp peaks of crystalline components corresponding to the (110) and (200) planes, as well as a broad halo pattern of amorphous components.

[0053] To determine whether a film to be measured is a uniaxially stretched film or a biaxially stretched film, it is possible to use in-plane measurement by X-ray diffraction, as described above. In this in-plane measurement, the X-ray incident angle θ and the angle 2θ at which the diffracted X-rays are detected by a detector are fixed to the angle θ and angle 2θ at which a diffraction peak corresponding to a specific crystal plane is detected in the above-mentioned out-of-plane measurement, for example, the diffraction peak corresponding to the (110) plane of a polyethylene film, and in this state, the film to be measured is scanned in the in-plane direction to obtain a diffraction pattern.

[0054] When in-plane measurement is performed on a uniaxially stretched film that has been uniaxially stretched in the machine direction (MD), a diffraction pattern can be obtained that has a sharp diffraction peak corresponding to the (110) plane at an angle 2θ of approximately ±90°, where MD is defined as 0°. On the other hand, in the case of a biaxially stretched film, the high-order structure obtained by uniaxial stretching is disrupted by the second stretching, and the anisotropy is reduced, so a diffraction pattern having a sharp diffraction peak corresponding to this (110) plane cannot be obtained. Therefore, in-plane measurement can be cited as one method for distinguishing between uniaxially stretched films and biaxially stretched films.

[0055] When a polymer film is uniaxially stretched, a higher-order structure called a shish kebab structure appears. The shish kebab structure consists of a shish structure, which is an extended chain crystal, and a kebab structure, which is a lamellar crystal. In a uniaxially stretched film, this higher-order structure is arranged with a high degree of order, and therefore, the X-ray diffraction pattern obtained by the above measurement of the uniaxially stretched film contains a sharp diffraction peak. In other words, when the above measurement is performed on a uniaxially stretched film, a clear diffraction peak appears. Note that a "clear diffraction peak" means a diffraction peak with a half-width of less than 10°.

[0056] In contrast, in the production of biaxially stretched films, the film is stretched in a specific direction and then stretched in a direction perpendicular to the first direction. Therefore, although the above-mentioned high-order structure is generated by the first stretching, this high-order structure is disrupted by the second stretching. Therefore, when the above-mentioned measurements are performed on biaxially stretched films, the resulting X-ray diffraction pattern exhibits broad diffraction peaks. In other words, when the above-mentioned measurements are performed on biaxially stretched films, no clear diffraction peaks are observed.

[0057] As described above, the X-ray diffraction patterns obtained by the above measurement differ between uniaxially stretched films and biaxially stretched films, and therefore, based on this, it is possible to determine whether a stretched film is a uniaxially stretched film or a biaxially stretched film.

[0058] The stretching ratios in the MD (machine direction) and TD (transverse direction) of the stretched film are preferably 2 to 10 times, and more preferably 3 to 7 times. By setting the stretching ratio in the MD or TD direction of the stretched film to 2 times or more, the strength and heat resistance of the laminate 10A can be improved, and the printability of the base material layer 2 can be improved. Furthermore, by setting the stretching ratio in the MD or TD direction to 2 times or more, the transparency of the base material layer 2 can be improved, thereby improving the visibility of the contents and the printed layer. On the other hand, the upper limit of the stretching ratio in the MD and TD directions of the stretched film is not particularly limited, but is preferably 10 times or less from the viewpoint of the breaking limit of the stretched film.

[0059] The film can be produced by known methods such as a casting method, an inflation method, etc. It is also possible to use a multilayer polyethylene film as the base layer 2, in which polyethylenes with different densities are extruded by a coextrusion method.

[0060] A multilayer structure including a layer made of high-density polyethylene (high-density polyethylene layer) and a layer made of medium-density polyethylene (medium-density polyethylene layer) may be used as the base layer 2. By providing the high-density polyethylene layer on the outer side of the base layer 2 (the side opposite the sealant layer side), the strength and heat resistance of the laminate 10A can be further improved. Furthermore, by providing the base layer 2 with a medium-density polyethylene layer, the stretchability of the resin film constituting the base layer 2 can be further improved.

[0061] The haze of the substrate layer 2 is preferably 20% or less, and more preferably 10% or less. Such a substrate layer 2 can improve the visibility of the contents and the printed layer. The haze is a value obtained by a method in accordance with JIS K7136:2000.

[0062] The thickness of the base layer 2 is preferably in the range of 10 μm to 200 μm, and more preferably in the range of 15 μm to 50 μm. If the base layer 2 is too thin, the strength of the laminate 10A tends to decrease. On the other hand, if the base layer 2 is too thick, the processability of the laminate 10A tends to decrease.

[0063] The substrate layer 2 is preferably surface-treated, which can improve the adhesion between the substrate layer 2 and the layer adjacent to the substrate layer 2.

[0064] The method of surface treatment is not particularly limited, and examples of the surface treatment include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0065] The base layer 2 may further contain additives, such as a crosslinking agent, an antioxidant, an antiblocking agent, a slip agent, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, and a modifying resin.

[0066] The proportion of polyethylene in the base layer 2 is preferably 50% by mass or more, and more preferably 80% by mass or more. In one example, the base layer 2 is made of polyethylene. In another example, the base layer 2 is made of polyethylene and an additive.

[0067] <1.3> Gas Barrier Layer The gas barrier layer 3 improves, for example, the oxygen barrier property and water vapor barrier property of the laminate 10A. The gas barrier layer 3 is composed of an inorganic compound layer, or an inorganic compound layer and a coating layer. When the gas barrier layer 3 is composed of an inorganic compound layer and a coating layer, the inorganic compound layer and the coating layer are preferably laminated in this order from the base layer 2 side.

[0068] The gas barrier layer 3 may be formed by coating or by vapor deposition of an inorganic compound.

[0069] Examples of inorganic compounds contained in the inorganic compound layer include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. The inorganic compound layer is preferably a vapor-deposited film made of a metal oxide. From the viewpoints of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of cost, the metal oxide is selected from aluminum oxide and silicon oxide. Furthermore, from the viewpoint of excellent tensile elongation during processing, it is more preferable to use silicon oxide as the metal oxide. By using a vapor-deposited film made of a metal oxide as the inorganic compound layer contained in the gas barrier layer 3, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the laminate 10A.

[0070] A vapor-deposited film made of a metal oxide has transparency, and therefore has the advantage that, compared to a vapor-deposited film made of a metal, it is less likely to cause a user who holds a packaging material made of a laminate to mistakenly believe that a metal foil is used.

[0071] The thickness of the vapor-deposited film made of aluminum oxide is preferably 5 nm or more and 30 nm or less. A film thickness of 5 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 30 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 30 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the film thickness of the vapor-deposited film made of aluminum oxide is more preferably 7 nm or more and 15 nm or less.

[0072] The thickness of the vapor-deposited film made of silicon oxide is preferably 10 nm or more and 50 nm or less. A film thickness of 10 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 50 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 50 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the film thickness of the vapor-deposited film made of silicon oxide is more preferably 20 nm or more and 40 nm or less.

[0073] The inorganic compound layer can be formed by, for example, vacuum film formation. In vacuum film formation, physical vapor deposition or chemical vapor deposition can be used. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD (Chemical Vapor Deposition), plasma CVD, and photo CVD.

[0074] In the vacuum film formation, resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, induction heating vacuum evaporation, sputtering, reactive sputtering, dual magnetron sputtering, plasma enhanced chemical vapor deposition (PECVD), and the like are particularly preferably used. However, in terms of productivity, vacuum evaporation is currently the most superior. As a heating means for vacuum evaporation, it is preferable to use any of the electron beam heating method, resistance heating method, and induction heating method.

[0075] An anchor coating layer may be formed on the surface of the substrate layer 2 on which the inorganic compound layer is to be formed, using a known anchor coating agent. This can improve the adhesion of the inorganic compound layer made of metal oxide. Examples of anchor coating agents include polyester-based polyurethane resins and polyether-based polyurethane resins. From the viewpoints of heat resistance and interlayer adhesive strength, polyester-based polyurethane resins are preferred as anchor coating agents.

[0076] The coating layer can be formed, for example, by coating. In this case, a coating liquid containing a resin such as polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyvinylidene chloride, polyacrylonitrile, or epoxy resin can be used. Additives such as organic or inorganic particles, layered compounds, and curing agents may also be added to this coating liquid.

[0077] The coating layer may be an organic-inorganic composite layer containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolyzate of a metal alkoxide, and a water-soluble polymer. This organic-inorganic composite layer may further contain at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolyzate of a silane coupling agent.

[0078] Examples of metal alkoxides and hydrolysates thereof contained in the organic-inorganic composite layer include tetraethoxysilane [Si(OC ２ H ５ ) ４] and triisopropoxyaluminum [Al(OC ３ H ７ ) ３ ] and the like, general formula M(OR) ｎ In the above general formula, M represents a metal, and R represents an alkyl group. One of these may be contained alone, or two or more may be contained in combination.

[0079] The total content of the metal alkoxide, its hydrolysate, or their reaction products in the coating liquid used to form the organic-inorganic composite layer may be, for example, 40% by mass or more, 50% by mass or more, or 65% by mass or more, from the viewpoint of oxygen barrier property. The total content of the metal alkoxide, its hydrolysate, or their reaction products in the coating liquid may be, for example, 70% by mass or less.

[0080] The water-soluble polymer contained in the organic-inorganic composite layer is not particularly limited, and examples thereof include polyvinyl alcohol-based polymers, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyol-based polymers. From the viewpoint of further improving the oxygen gas barrier property, the water-soluble polymer preferably contains a polyvinyl alcohol-based water-soluble polymer. The number average molecular weight of the water-soluble polymer is, for example, 40,000 to 180,000.

[0081] The polyvinyl alcohol-based water-soluble polymer contained in the organic-inorganic composite layer can be obtained, for example, by saponifying (including partial saponification) polyvinyl acetate. This water-soluble polymer may have several tens of percent or only a few percent of acetate groups remaining.

[0082] The content of the water-soluble polymer in the coating liquid used to form the organic-inorganic composite layer may be, for example, 15% by mass or more, or 20% by mass or more, from the viewpoint of oxygen barrier property, and may be, for example, 50% by mass or less, or 45% by mass or less, from the viewpoint of oxygen barrier property.

[0083] Examples of silane coupling agents used in the organic-inorganic composite layer include silane coupling agents having an organic functional group. Examples of such silane coupling agents include ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. Silane coupling agents selected from these, their hydrolysates, and reaction products thereof can be used alone or in combination of two or more.

[0084] It is preferable to use a silane coupling agent having an epoxy group as the organic functional group. Examples of silane coupling agents having an epoxy group include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The silane coupling agent having an epoxy group may have an organic functional group other than the epoxy group, such as a vinyl group, an amino group, a methacryl group, or a ureyl group. One of the silane coupling agents selected from these, their hydrolysates, and their reaction products may be used alone, or two or more of them may be used in combination.

[0085] A silane coupling agent having an organic functional group, its hydrolyzate, or a reaction product thereof can further improve the oxygen barrier property of the organic-inorganic composite layer and the adhesion to an adjacent layer through the interaction between the organic functional group and the hydroxyl group of the water-soluble polymer. In particular, when the silane coupling agent, its hydrolyzate, or a reaction product thereof has an epoxy group and the water-soluble polymer is polyvinyl alcohol (PVA), the interaction between the epoxy group and the hydroxyl group of the PVA can further improve the oxygen barrier property and the adhesion to an adjacent layer.

[0086] The total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid used to form the organic-inorganic composite layer may be, for example, 1% by mass or more, or 2% by mass or more, from the viewpoint of oxygen barrier property. Also, the total content of the silane coupling agent, its hydrolysate, and their reaction products in the coating liquid may be, for example, 15% by mass or less, or 12% by mass or less, from the viewpoint of oxygen barrier property.

[0087] The thickness of the coating layer is preferably 50 nm to 1000 nm, more preferably 100 nm to 500 nm. When the thickness of the gas barrier coating layer is 50 nm or more, more sufficient gas barrier properties tend to be obtained, and when it is 1000 nm or less, sufficient flexibility tends to be maintained.

[0088] The gas barrier layer 3 is preferably subjected to the above-mentioned surface treatment. This can improve the adhesion between the gas barrier layer 3 and the adjacent layer. Note that a nanocomposite may also be used as the material for the gas barrier layer 3.

[0089] <1.4> Printed Layer The printed layer 4 is a layer composed of ink and displays patterns such as letters and pictures. The ink has a composition in which additives such as various pigments, extender pigments, plasticizers, desiccants, and stabilizers are added to a conventionally used ink binder resin, such as a urethane-based, acrylic-based, nitrocellulose-based, rubber-based, or vinyl chloride-based ink. It is preferable to use an ink derived from biomass. Light-blocking inks can also be preferably used. Examples of light-blocking inks include white ink, black ink, silver ink, and sepia ink.

[0090] Examples of methods that can be used to form the printed layer 4 include well-known printing methods such as offset printing, gravure printing, flexographic printing, and silk screen printing, and well-known coating methods such as roll coating, knife edge coating, and gravure coating. In particular, aqueous flexographic printing is preferred because it imposes a small printing load on the substrate layer and is also environmentally friendly.

[0091] <1.5> Adhesive Layer The adhesive layer 5 contains at least one type of adhesive. The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may also be a solventless adhesive or a solvent-based adhesive.

[0092] Examples of adhesives include epoxy adhesives such as polyether adhesives, polyester adhesives, silicone adhesives, and polyamine adhesives, as well as urethane adhesives, rubber adhesives, vinyl adhesives, silicone adhesives, epoxy adhesives, phenol adhesives, and olefin adhesives. Adhesives containing biomass components can also be preferably used.

[0093] The adhesive is preferably an epoxy adhesive such as a polyamine adhesive having gas barrier properties, or a urethane adhesive such as a polyester-polyurethane adhesive. Specific examples of gas barrier adhesives include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation.

[0094] The adhesive layer 5 may be a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound. Such an adhesive layer 5 can further improve the oxygen barrier property and water vapor barrier property of the laminate 10A.

[0095] The thickness of the adhesive layer 5 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.

[0096] The adhesive layer 5 can be formed by applying and drying on the sealant layer 6 using a conventionally known method such as a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, or a transfer roll coating method.

[0097] <1.6> Sealant Layer The sealant layer 6 contains polyethylene. As the polyethylene, for example, the polyethylenes described above for the base layer 2 can be used. The sealant layer 6 is preferably low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very low-density polyethylene (VLDPE), and more preferably linear low-density polyethylene.

[0098] From the viewpoint of environmental load, the polyethylene is preferably biomass-derived polyethylene or recycled polyethylene.

[0099] The sealant layer 6 may be transparent or opaque. In the latter case, the sealant layer 6 may be colored, and is preferably white. When the laminate 10A has a transparent sealant layer 6, the contents are easily visible when used in a package. When the laminate 10A has an opaque sealant layer 6, the contents do not interfere with the visibility of the image displayed by the printing layer 4 when used in a package. In particular, a white sealant layer 6 improves the visibility of the image displayed by the printing layer 4.

[0100] The sealant layer 6 may further contain the additives described above in the section "<1.2> Base layer." The proportion of polyethylene in the sealant layer 6 is preferably 50% by mass or more, and more preferably 80% by mass or more. In one example, the sealant layer 6 is made of polyethylene. In another example, the sealant layer 6 is made of polyethylene and an additive.

[0101] The thickness of the sealant layer 6 can be appropriately set in consideration of the shape of the packaging bag to be manufactured, the mass of the contents to be contained, etc., and can be in the range of 30 to 150 μm, for example.

[0102] The sealant layer 6 is, for example, a non-oriented polyethylene resin film or a layer formed by melt-extrusion of polyethylene.

[0103] <1.7> Effects The laminate 10A described above has excellent heat resistance and transparency, which will be described below.

[0104] The manufacture of packaging bags generally involves a process of bringing sealant layers of a laminate into contact with each other, clamping the contact area with a jig, and applying pressure and heat to the contact area to thermally weld (heat seal) the contact area. The jig of the heat sealing machine is heated to a high temperature, and the surface of the base layer that directly contacts the jig is exposed to high temperatures. As a result, when polyethylene, which has poor heat resistance, is used for the base layer, the surface of the base layer may be affected by heat, resulting in problems such as adhesion to the jig. Therefore, conventional laminates using polyethylene for the base layer have a narrow range of appropriate bag-making temperatures, which has led to poor productivity.

[0105] The inventors have found that when the degree of molecular orientation of the base layer 2 is 1.07 or more, the base layer 2 exhibits excellent heat resistance, and therefore the laminate 10A also exhibits excellent heat resistance, and in particular achieves good heat sealing suitability.

[0106] In the laminate 10A, polyethylene, which is generally considered to have poor heat resistance, is used as the base layer 2. However, by setting the degree of molecular orientation of the base layer 2 to 1.07 or more, the temperature range of heat sealing performed for bag production is expanded, and productivity is not reduced.

[0107] Furthermore, the laminate 10A contains polyethylene at a rate of 90% by mass or more, and therefore the laminate 10A is highly recyclable.

[0108] <1.8> Modifications In FIG. 1 , the laminate 10A includes a printed layer 4 between the gas barrier layer 3 and the adhesive layer 5, but the printed layer 4 may be provided anywhere between the substrate layer 2 and the sealant layer 6. For example, the printed layer 4 may be provided on the surface of the substrate layer 2 facing the sealant layer 6 (i.e., the back surface of the substrate layer 2). Alternatively, the printed layer 4 may be provided on the surface of the substrate layer 2. Furthermore, multiple printed layers 4 may be provided. Because the substrate layer 2 has excellent transparency, even if the printed layer 4 is included between the substrate layer 2 and the sealant layer 6, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10A is observed from the substrate layer 2 side. Alternatively, the printed layer 4 may be omitted.

[0109] An anchor coat layer may be formed on the main surface of the base layer 2 that faces the gas barrier layer 3. The gas barrier layer 3 may be omitted.

[0110] In order to impart light-blocking properties to the laminate 10A, a metal vapor-deposited layer may be provided on the base material layer 2 or the sealant layer 6. When the laminate 10A includes an intermediate layer described below, a metal vapor-deposited layer may be provided on the intermediate layer. An example of the metal vapor-deposited layer is an aluminum vapor-deposited layer.

[0111] As already mentioned, the sealant layer 6 may be opaque, but the base layer 2 may also be opaque. The base layer 2 may be colored, for example, white. When the laminate 10A includes an intermediate layer described below, the intermediate layer may be opaque. The intermediate layer may be colored, for example, white.

[0112] <2> Second embodiment <2.1> Laminate Fig. 2 is a cross-sectional view schematically showing a laminate according to a second embodiment of the present invention. The laminate 10B shown in Fig. 2 is similar to the laminate 10A, except that it further includes a protective layer 1 provided on the surface of the base layer 2.

[0113] <2.2> Protective Layer The protective layer 1 is the outermost layer facing the sealant layer 6 with the base layer 2 sandwiched therebetween. Here, the protective layer 1 covers the surface of the base layer 2.

[0114] The protective layer 1 is made of a thermosetting resin. That is, the protective layer 1 is a thermosetting resin layer. The cured product of the thermosetting resin is not particularly limited as long as it has heat resistance. Examples of the thermosetting resin include polyurethane resin, polyester resin, polyamide resin, polyamideimide resin, acrylic resin, and epoxy resin. The protective layer 1 may contain one type of the above-mentioned thermosetting resin, or may contain two or more types.

[0115] In one embodiment, the protective layer 1 preferably contains a water-soluble polymer, and is preferably an organic-inorganic composite layer that further contains an organometallic compound.

[0116] Examples of water-soluble polymers include polyvinyl alcohols, polysaccharides such as starch, methyl cellulose, and carboxymethyl cellulose, and hydroxyl group-containing polymers such as acrylic polyols. In one embodiment, the protective layer 1 preferably contains a polyvinyl alcohol-based hydroxyl group-containing polymer that may be contained in a coating layer serving as the gas barrier layer 3 described below.

[0117] The protective layer 1 preferably contains, as an organometallic compound, at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolyzate thereof. Examples of the metal alkoxide include tetraethoxysilane [Si(OC ２ H ５ ) ４ ] and triisopropoxyaluminum [Al(OC ３ H ７ ) ３ ] and the like, general formula M(OR) ｎ Examples include those represented by the following formula:

[0118] Furthermore, the protective layer 1 preferably further contains, as the organometallic compound, at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0119] In one embodiment, the protective layer 1 can be formed using a coating liquid for forming a coating layer as the gas barrier layer 3, which will be described later. When the laminate 10B includes an inorganic compound layer and a coating layer as the gas barrier layer 3, the protective layer 1 may be a layer formed using the same coating liquid as the coating liquid used to form the coating layer.

[0120] As the thickness of the protective layer 1 increases, higher heat resistance tends to be achieved. In order to achieve high heat resistance, the thickness of the protective layer 1 is preferably 0.3 μm or more. Furthermore, as the thickness of the protective layer 1 increases, it tends to become difficult to sufficiently dry the resin coating film during the manufacturing process of the laminate 10B. From the viewpoint of productivity, the thickness of the protective layer 1 is preferably 3 μm or less.

[0121] <2.3> Effects The laminate 10B includes the protective layer 1. As described above, the protective layer 1 reduces thermal damage to the surface of the laminate 10B during heat sealing. Therefore, the laminate 10B can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for the laminate 10B, the temperature range for heat sealing performed for bag production is expanded, making it even less likely that a decrease in productivity will occur.

[0122] Furthermore, since the protective layer 1 is substantially transparent, the image displayed by the printing layer 4 can be seen from the surface side even if the laminate 10B further includes the protective layer 1. That is, the laminate 10B has excellent transparency and also excellent heat resistance. Furthermore, since the proportion of polyethylene in the laminate 10B is 90% by mass or more, it also has excellent recyclability.

[0123] 2, the laminate 10B includes a printed layer 4 between the gas barrier layer 3 and the adhesive layer 5, but the printed layer 4 may be provided anywhere between the protective layer 1 and the sealant layer 6. Because the base layer 2 has excellent transparency, even when the printed layer 4 is included between the protective layer 1 and the sealant layer 6, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10B is observed from the protective layer 1 side. Alternatively, the printed layer 4 may be omitted.

[0124] An anchor coat layer may be formed on the main surface of the base layer 2 that faces the gas barrier layer 3. The gas barrier layer 3 may be omitted.

[0125] <3> Third Embodiment <3.1> Laminate Figure 3 is a cross-sectional view schematically showing a laminate according to a third embodiment of the present invention. The laminate 10C shown in Figure 3 is similar to the laminate 10A except for the following points. That is, the laminate 10C further includes an intermediate layer 7. Furthermore, the laminate 10C includes a first adhesive layer 5A and a second adhesive layer 5B instead of the adhesive layer 5. That is, the laminate 10C includes a substrate layer 2, a printing layer 4, a first adhesive layer 5A, an intermediate layer 7, a gas barrier layer 3, a second adhesive layer 5B, and a sealant layer 6, in this order.

[0126] <3.2> Intermediate Layer The intermediate layer 7 is interposed between the base layer 2 and the sealant layer 6. The intermediate layer 7 contains polyethylene. In the laminate 10C, the absolute value of the molecular orientation degree of the intermediate layer 7, measured by a microwave method, is 1.07 or more, preferably 1.10 or more, more preferably 1.15 or more, even more preferably 1.20 or more, even more preferably 1.25 or more, and even more preferably 1.30 or more. In this case, the upper limit of the molecular orientation degree of the intermediate layer 7 is not particularly limited, but is, for example, 2.0 or less, 1.8 or less, or 1.5 or less. Such an intermediate layer 7 has excellent transparency and can contribute to improving the strength of the laminate 10C, particularly its puncture strength.

[0127] The "puncture strength" of the laminate is a value obtained by piercing the laminate 10C from the base layer 2 side using the method specified in JIS Z1707:2019 "General Rules for Food Packaging Plastic Films." Specifically, a needle with a diameter of 1 mm and a semicircular tip is pierced from the base layer 2 side of the laminate 10C 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 average of the maximum forces is obtained as the puncture strength.

[0128] The polyethylene contained in the intermediate layer 7 can be, for example, the polyethylene contained in the base material layer 2 described above in the first embodiment. The intermediate layer 7 is, for example, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or very-low-density polyethylene (VLDPE). Among these, high-density polyethylene and medium-density polyethylene are preferred from the viewpoints of the printability, strength, and heat resistance of the laminate 10C and the stretchability of the film, and medium-density polyethylene is more preferred from the viewpoint of stretchability.

[0129] The polyethylene contained in the intermediate layer 7 may be the same as or different from the polyethylene contained in the base layer 2. Furthermore, the intermediate layer 7 may further contain the additives described above.

[0130] The intermediate layer 7 is preferably a stretched film. When the intermediate layer 7 is a stretched film, the intermediate layer 7 may be a uniaxially stretched film or a biaxially stretched film. The stretched film constituting the intermediate layer 7 may be the same as or different from the stretched film constituting the base layer 2.

[0131] The use of a uniaxially stretched film as the intermediate layer 7 improves heat resistance during bag production, and the use of a biaxially stretched film as the intermediate layer 7 improves the drop strength of a packaged article using the laminate 10C as a packaging material.

[0132] Whether the stretched film is a uniaxially stretched film or a biaxially stretched film can be determined by carrying out in-plane measurement using X-ray diffraction, as explained in the section on the first embodiment.

[0133] The molecular orientation degree of the intermediate layer 7 is preferably 1.07 or more as an average of the molecular orientation degrees measured at the center and edges of the intermediate layer 7, and more preferably 1.07 or more as measured at the center of the intermediate layer 7. The molecular orientation degree of the intermediate layer 7 can also be adjusted by selecting the material thereof, as described for the molecular orientation degree of the base layer 2 in the section "<1.2> Base layer" in the first embodiment. The stretched film constituting the intermediate layer 7 may be the same as or different from the stretched film constituting the base layer 2.

[0134] In this embodiment, an intermediate layer having an absolute value of the molecular orientation degree measured by a microwave method of less than 1.07 may be used. By using an intermediate layer having an absolute value of the molecular orientation degree measured by a microwave method of less than 1.07, the strength, particularly the drop strength, of the laminate 10C can be improved. As an intermediate layer having an absolute value of the molecular orientation degree measured by a microwave method of less than 1.07, a non-stretched film is preferably used.

[0135] The proportion of polyethylene in the intermediate layer 7 is preferably 50% by mass or more, and more preferably 80% by mass or more. In one example, the intermediate layer 7 is made of polyethylene. In another example, the intermediate layer 7 is made of polyethylene and an additive.

[0136] The thickness of the intermediate layer 7 is preferably in the range of 10 μm to 200 μm, and more preferably in the range of 15 μm to 50 μm.

[0137] The intermediate layer 7 can be produced by a known method such as the above-mentioned casting method or inflation method, and it is also possible to use a multilayer polyethylene film obtained by co-extruding polyethylenes of different densities as the intermediate layer 7.

[0138] The intermediate layer 7 is preferably surface-treated, similarly to the substrate layer 2. This treatment can improve adhesion between the intermediate layer 7 and adjacent layers. The method of surface treatment is not particularly limited. Examples of surface treatments include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

[0139] <3.3> Adhesive layer The first adhesive layer 5A is interposed between the printing layer 4 and the intermediate layer 7, bonding them together. The second adhesive layer 5B is interposed between the gas barrier layer 3 and the sealant layer 6, bonding them together. These adhesive layers improve the adhesion between the layers.

[0140] The adhesives described in the section "<1.5> Adhesive Layer" in the first embodiment can be used as the adhesives for forming the first adhesive layer 5A and the second adhesive layer 5B. The material of the second adhesive layer 5B may be the same as or different from the material of the first adhesive layer 5A.

[0141] The thickness of the first adhesive layer 5A and the second adhesive layer 5B 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.

[0142] The first adhesive layer 5A and the second adhesive layer 5B can be formed by applying and drying on the base material layer 2 or the sealant layer 6 using a conventionally known method such as a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fountain method, or a transfer roll coating method.

[0143] <3.4> Effects In the laminate 10C, the degree of molecular orientation of the base layer 2 is 1.07 or more. Therefore, the laminate 10C is excellent in heat resistance and transparency, similar to the laminate 10A.

[0144] Furthermore, the laminate 10C includes an intermediate layer 7 having a degree of molecular orientation of 1.07 or more. The intermediate layer 7 increases the strength, particularly the puncture strength, of the laminate 10C. Therefore, the laminate 10C has excellent strength, particularly the puncture strength.

[0145] Furthermore, the laminate 10C has an excellent recyclability since the proportion of polyethylene is 90% by mass or more.

[0146] Furthermore, laminates with a high proportion of polyethylene are weaker than other laminates, and therefore are frequently bent when used as packaging materials. Frequent bending increases the likelihood of pinholes occurring, but laminate 10C, which has excellent puncture resistance, is less likely to develop pinholes.

[0147] 3, the laminate 10C includes the printed layer 4 between the base material layer 2 and the first adhesive layer 5A, but the printed layer 4 may be provided anywhere between the base material layer 2 and the sealant layer 6. Because the base material layer 2 and the intermediate layer 7 have excellent transparency, even when the printed layer 4 is included between the base material layer 2 and the sealant layer 6, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10C is observed from the side of the base material layer 2. Alternatively, the printed layer 4 may be omitted.

[0148] An anchor coat layer may be formed on the main surface of the base layer 2 that faces the printed layer 4. The gas barrier layer 3 may be omitted.

[0149] <4> Fourth embodiment <4.1> Laminate Fig. 4 is a cross-sectional view schematically showing a laminate according to a fourth embodiment of the present invention. The laminate 10D shown in Fig. 4 is similar to the laminate 10C, except that it further includes a protective layer 1 provided on the surface of the base layer 2. The protective layer 1 may be the same as that described in the second embodiment.

[0150] <4.2> Effects The laminate 10D has a molecular orientation degree of 1.07 or more in the base material layer 2. The laminate 10D also includes a protective layer 1. Therefore, the laminate 10D can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for the laminate 10D, the temperature range for heat sealing performed for bag production is expanded, further reducing the likelihood of a decrease in productivity.

[0151] Furthermore, since the protective layer 1 is substantially transparent, the image displayed by the printing layer 4 can be seen from the surface side even if the laminate 10D further includes the protective layer 1. In other words, the laminate 10D has excellent transparency and further excellent heat resistance.

[0152] Furthermore, the laminate 10D includes an intermediate layer 7 having a degree of molecular orientation of 1.07 or more. The intermediate layer 7 increases the strength, particularly the puncture strength, of the laminate 10D. Therefore, the laminate 10D has excellent strength, particularly the puncture strength.

[0153] Furthermore, the laminate 10D has an excellent recyclability since the proportion of polyethylene is 90% by mass or more.

[0154] 4, the laminate 10D includes the printed layer 4 between the base layer 2 and the first adhesive layer 5A, but the printed layer 4 may be provided anywhere between the protective layer 1 and the sealant layer 6. Because the base layer 2 and the intermediate layer 7 have excellent transparency, even when the printed layer 4 is included between the protective layer 1 and the sealant layer 6, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10D is observed from the protective layer 1 side. Alternatively, the printed layer 4 may be omitted.

[0155] An anchor coat layer may be formed on the main surface of the base layer 2 that faces the printed layer 4. The gas barrier layer 3 may be omitted.

[0156] <5> Fifth Embodiment <5.1> Laminate Figure 5 is a cross-sectional view schematically illustrating a laminate according to a fifth embodiment of the present invention. The laminate 10E shown in Figure 5 is similar to the laminate 10C, except that the molecular orientation degree of the intermediate layer 7 is 1.07 or less. That is, the intermediate layer 7 is interposed between the substrate layer 2 and the sealant layer 6. The intermediate layer 7 contains polyethylene. In the laminate 10E, the absolute value of the molecular orientation degree of the intermediate layer 7 measured by a microwave method is 1.07 or less, preferably less than 1.07. In the laminate 10E, the intermediate layer 7 is preferably a non-stretched film. Such an intermediate layer 7 can contribute to improving the strength of the laminate 10E, particularly its drop strength.

[0157] <5.2> Effects In the laminate 10E, the degree of molecular orientation of the base layer 2 is 1.07 or more. Therefore, the laminate 10E is excellent in heat resistance and transparency, similar to the laminate 10A.

[0158] The laminate 10E also includes an intermediate layer 7 having a molecular orientation degree of 1.07 or less, preferably less than 1.07. This intermediate layer 7 increases the strength of the laminate 10E, particularly its drop strength. That is, when the laminate 10E is used in a package, the intermediate layer 7 located inside the base layer 2 is softer than the base layer 2. This structure is suitable for absorbing the impact that occurs when a packaged item using the laminate 10E as a packaging material is dropped. Therefore, a packaged item using the laminate 10E as a packaging material is less likely to break (break) when dropped. Therefore, the laminate 10E has excellent strength, particularly its drop strength.

[0159] In this embodiment, an intermediate layer having an absolute value of the molecular orientation degree measured by a microwave method of 1.07 or more may be used. When an intermediate layer having an absolute value of the molecular orientation degree measured by a microwave method of 1.07 or more is used, the strength of the laminate 10E, particularly the puncture strength, can be improved. As an intermediate layer having an absolute value of the molecular orientation degree measured by a microwave method of 1.07 or more, a stretched film is preferably used.

[0160] Furthermore, the laminate 10E has an excellent recyclability since the proportion of polyethylene is 90% by mass or more.

[0161] 5, the laminate 10E includes the printed layer 4 between the base material layer 2 and the first adhesive layer 5A, but the printed layer 4 may be provided anywhere between the base material layer 2 and the intermediate layer 7. Because the base material layer 2 has excellent transparency, even if the printed layer 4 is included between the base material layer 2 and the intermediate layer 7, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10E is observed from the base material layer 2 side. Alternatively, the printed layer 4 may be omitted.

[0162] An anchor coat layer may be formed on the main surface of the base layer 2 that faces the printed layer 4. The gas barrier layer 3 may be omitted.

[0163] <6> Sixth Embodiment <6.1> Laminated Body FIG. 6 is a cross-sectional view schematically showing a laminated body according to a sixth embodiment of the present invention.

[0164] 6 is similar to the laminate 10E except that it further includes a protective layer 1 provided on the surface of the base layer 2. As the protective layer 1, the one described in the second embodiment can be used.

[0165] <6.2> Effects The laminate 10F has a molecular orientation degree of 1.07 or more in the base layer 2. The laminate 10F also includes a protective layer 1. Therefore, the laminate 10F can achieve even better heat resistance, particularly better heat sealing suitability. Therefore, when the above-described configuration is adopted for the laminate 10F, the temperature range for heat sealing performed for bag production is expanded, making it even less likely that a decrease in productivity will occur.

[0166] Furthermore, since the protective layer 1 is substantially transparent, the image displayed by the printing layer 4 can be seen from the surface side even if the laminate 10F further includes the protective layer 1. In other words, the laminate 10F has excellent transparency and further excellent heat resistance.

[0167] The laminate 10F also includes an intermediate layer 7 having a degree of molecular orientation of 1.07 or less, preferably less than 1.07. The intermediate layer 7 increases the strength, particularly the drop strength, of the laminate 10F. Therefore, the laminate 10F is excellent in strength, particularly the drop strength.

[0168] Furthermore, the laminate 10F has an excellent recyclability since the proportion of polyethylene is 90% by mass or more.

[0169] 6, the laminate 10F includes the printed layer 4 between the base layer 2 and the first adhesive layer 5A, but the printed layer 4 may be provided anywhere between the protective layer 1 and the intermediate layer 7. Because the base layer 2 has excellent transparency, even if the printed layer 4 is included between the protective layer 1 and the intermediate layer 7, the pattern displayed by the printed layer 4 can be clearly seen when the laminate 10F is observed from the protective layer 1 side. Alternatively, the printed layer 4 may be omitted.

[0170] An anchor coat layer may be formed on the main surface of the base layer 2 that faces the printed layer 4. The gas barrier layer 3 may be omitted.

[0171] <7> Seventh Embodiment FIG. 7 is a diagram schematically showing a packaged article according to a seventh embodiment of the present invention.

[0172] The packaged article 100A shown in FIG. 7 includes a package 110A and contents contained therein.

[0173] The package 110A is a flat pouch. The package 110A includes a pair of main films. Each of the main films is one of the laminates described in the first to sixth embodiments, or is cut out from such a laminate. The main films are overlapped with their sealant layers facing each other, and the peripheral edges are heat-sealed to each other. The package 110A has a notch in the heat-sealed portion as an easy-open structure.

[0174] The contents may be any of liquids, solids, and mixtures thereof, such as food or medicine.

[0175] <8> Eighth Embodiment FIG. 8 is a diagram schematically showing a packaged article according to an eighth embodiment of the present invention.

[0176] 8 includes a package 110B and contents housed therein. The contents may be the same as those described for the package 100A, for example.

[0177] The package 110B is a stand-up pouch. The package 110B includes a pair of body and bottom films. Each of these films is one of the laminates described in the first to sixth embodiments, or is cut from the laminate.

[0178] The pair of main films are overlapped with their sealant layers facing each other, and their peripheral edges are heat-sealed to each other except for one end and the area nearby. The bottom film is folded in half to form a mountain fold when viewed from the sealant layer side, and is sandwiched between the pair of main films at the one end with the mountain fold facing the other end of the main film. The bottom film is heat-sealed to the pair of main films except for its center. The outer surfaces of the bottom films are bonded to each other at both sides of the bottom of the package 110B.

[0179] The package 110B has a notch as an easy-open structure at the heat-sealed portion of the main film. The easy-open structure may be provided so that the upper corner of the package 100B can be used as a mouth when the package 100B is opened. Alternatively, the package 100B may further include a mouth member and a lid as described in the ninth embodiment.

[0180] <9> Ninth Embodiment FIG. 9 is a diagram schematically showing a packaged article according to a ninth embodiment of the present invention.

[0181] 9 includes a package 110C and contents contained therein, which may be the same as those described for the package 100A.

[0182] The package 110C is a gusset-type pouch and includes a container body 110C1, a spout 110C2, and a lid 110C3.

[0183] The container body 110C1 includes a pair of body films and a pair of side films.

[0184] The pair of main films are overlapped with their sealant layers facing each other and sandwiching a portion of the mouth member 110C2 at one end. The peripheral edges of the main films are heat-sealed to the mouth member 110C2 at the one end and are also heat-sealed to each other in the vicinity of the one end. The peripheral edges of the main films are also heat-sealed to each other at the opposite end, except for the side regions.

[0185] Each of the side films is folded in half to form a mountain fold when viewed from the sealant layer side. The side films are sandwiched between a pair of main films on both sides of the main films with the mountain folds facing each other. A portion of the periphery of each of the side films is heat-sealed to one of the main films, and the remaining portion of the periphery is heat-sealed to the other main film. The outer surfaces of the side films are bonded together at the top and bottom of the package 110C. The container body 110C1 may further include a bottom film.

[0186] As described above, the mouth member 110C2 is sandwiched between the main body films and includes a portion where they are heat-sealed. The mouth member 110C2 further includes a mouth portion that protrudes outward from the container body 110C1. The mouth portion has a generally cylindrical shape and is provided with a male thread on the outer surface of the side wall. The lid body 110C3 has a cylindrical shape with a bottom. The lid body 110C3 has a female thread on the inner surface of the side wall that screws into the mouth portion of the mouth member 110C2.

[0187] The results of tests carried out in connection with the present invention are described below.

[0188] (1) Test A (1.1) Production of Laminate (1.1.1) Example 1A Polyethylene film (thickness 25 μm, density 0.950 g / cm 3) as a substrate layer ３ On the corona-treated surface of a substrate (one-sided corona-treated, one-sided corona-treated), a 40-nm-thick inorganic compound layer made of silicon oxide was formed using a vacuum deposition apparatus employing an electron beam heating system. Next, a design was printed on the inorganic compound layer using gravure ink to form a printed layer. Next, a urethane-based adhesive was applied to the printed layer, and then a 60-μm-thick unstretched film (60 μm thick) made of linear low-density polyethylene resin was laminated onto the adhesive layer as a sealant layer. This resulted in a laminate having a laminate structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer.

[0189] (1.1.2) Example 2A A laminate having a laminate structure of substrate layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that the inorganic compound layer was not formed.

[0190] (1.1.3) Example 3A A laminate having a laminated structure of base material layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a polyamine-based gas barrier adhesive was used on the printed layer instead of the urethane-based adhesive.

[0191] (1.1.4) Example 4A: As a substrate layer, a polyethylene film (thickness 25 μm, density 0.950 g / cm ３ A laminate having a laminate structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a 1000-kJ / 2000-kJ / 2000-kJ / 3000-kJ / 4000-kJ / 5000-kJ / 6000-kJ / 7000-kJ / 8000kJ / 9000kJ / 10000kJ / 11000kJ / 12000kJ / 13000kJ / 14000kJ / 15000kJ / 16000kJ / 17000kJ / 18000kJ / 19000kJ / 20000kJ / 21000kJ / 31000kJ / 22000kJ / 24000kJ / 32000kJ / 430

[0192] (1.1.5) Example 5A: As a substrate layer, a polyethylene film (thickness 20 μm, density 0.950 g / cm ３ A laminate having a laminate structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a 1000-kJ / 2000kJ / 2000kcal / 1000kcal ...

[0193] (1.1.6) Example 6A: As a substrate layer, a polyethylene film (thickness 30 μm, density 0.950 g / cm ３ A laminate having a laminate structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a 1000-kJ / 2000kJ / 2000kcal / 1000kcal ...

[0194] (1.1.7) Example 7A A laminate having a laminated structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a linear low-density polyethylene resin (LLDPE) film having a thickness of 40 μm was used as the sealant layer.

[0195] (1.1.8) Example 8A A laminate having a laminated structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a linear low-density polyethylene resin (LLDPE) film having a thickness of 120 μm was used as the sealant layer.

[0196] (1.1.9) Example 9A A laminate having a laminate structure of base material layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that no inorganic compound layer was formed and a polyamine-based gas barrier adhesive was used instead of a urethane-based adhesive.

[0197] (1.1.10) Example 10A A laminate having a laminate structure of base material layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that no inorganic compound layer was formed and a urethane-based gas barrier adhesive was used instead of a urethane-based adhesive.

[0198] (1.1.11) Example 11A A laminate according to Example 11A was produced in the same manner as the laminate according to Example 1A, except that the following film was used as the substrate layer. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.08, a haze of 5.9%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ is.

[0199] (1.1.12) Comparative Example 1A: As a substrate layer, a polyethylene film (thickness 40 μm, density 0.949 g / cm ３ A laminate having a laminate structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a 1000-kJ / 2000-kJ / 2000-kJ / 3000-kJ / 4000-kJ / 5000-kJ / 6000-kJ / 7000-kJ / 8000kJ / 9000kJ / 10000kJ / 11000kJ / 12000kJ / 13000kJ / 14000kJ / 15000kJ / 16000kJ / 17000kJ / 18000kJ / 19000kJ / 20000kJ / 21000kJ / 31000kJ / 22000kJ / 24000kJ / 32000kJ / 430

[0200] (1.1.13) Comparative Example 2A: As a substrate layer, a polyethylene film (thickness 25 μm, density 0.950 g / cm ３ A laminate having a laminate structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a 1000-kJ / 2000-kJ / 2000-kJ / 3000-kJ / 4000-kJ / 5000-kJ / 6000-kJ / 7000-kJ / 8000kJ / 9000kJ / 10000kJ / 11000kJ / 12000kJ / 13000kJ / 14000kJ / 15000kJ / 16000kJ / 17000kJ / 18000kJ / 19000kJ / 20000kJ / 21000kJ / 31000kJ / 22000kJ / 24000kJ / 32000kJ / 430

[0201] (1.1.14) Comparative Example 3A: As a substrate layer, a polyethylene film (thickness 25 μm, density 0.952 g / cm ３ A laminate having a laminate structure of substrate layer / inorganic compound layer / printed layer / adhesive layer / sealant layer was obtained in the same manner as in Example 1A, except that a 1000-kJ / 2000-kJ / 2000-kJ / 3000-kJ / 4000-kJ / 5000-kJ / 6000-kJ / 7000-kJ / 8000kJ / 9000kJ / 10000kJ / 11000kJ / 12000kJ / 13000kJ / 14000kJ / 15000kJ / 16000kJ / 17000kJ / 18000kJ / 19000kJ / 20000kJ / 21000kJ / 31000kJ / 22000kJ / 24000kJ / 32000kJ / 430

[0202] (1.2) Measurement and Evaluation Methods The recyclability, heat resistance, visibility, and gas barrier property of the laminate were evaluated. The method for measuring the molecular orientation ratio (MOR) and the methods for evaluating the recyclability, heat resistance, visibility, and gas barrier property are described below.

[0203] (1.2.1) Method for Measuring Molecular Orientation Ratio (MOR) The molecular orientation ratio (MOR) of the substrate layer was measured using a microwave molecular orientation meter (trade name: MOA-5012A, manufactured by Oji Scientific Instruments Co., Ltd.).

[0204] (1.2.2) Method for Evaluating Recyclability The recyclability of the above laminate was evaluated based on the following evaluation criteria: A: The polyethylene content in the laminate was 90% by mass or more. B: The polyethylene content in the laminate was less than 90% by mass.

[0205] (1.2.3) Method for evaluating heat resistance at 140°C The above laminate was cut into a 10 cm square to prepare a sample piece. The sample piece was folded in half with the sealant layer facing inward, and heat-sealed using a heat seal tester at a temperature of 140°C, 0.1 MPa, and 1 second. The sample piece after heat sealing was visually observed, and its appearance was evaluated based on the following evaluation criteria. A: The surface was not melted, and there was no problem with the appearance. B: The surface was melted, and there was a problem with the appearance.

[0206] (1.2.4) Evaluation Method for Heat Resistance at 170°C The above laminate was cut into a 10 cm square to obtain a sample piece. Next, the sample piece was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was fixed at 30°C, and the top sealing temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample piece for 1 second. The presence or absence of melting of the sealed surface was observed, and the area of ​​the top surface of the folded sample piece that was contacted with the heat seal bar was observed to see if it adhered to the heat seal bar. Heat resistance was evaluated based on the following evaluation criteria. A: The top surface of the sample piece did not adhere to the heat seal bar. B: The top surface of the sample piece adhered to the heat seal bar.

[0207] (1.2.5) Method for evaluating visibility The above laminate was visually observed, and the visibility of the printed layer from the base layer side was evaluated based on the following evaluation criteria: A: The printed pattern was clearly visible. B: The printed pattern was blurred or appeared faint.

[0208] (1.2.6) Method for evaluating gas barrier properties The oxygen permeability (cc / m) of the above laminate was measured under an atmosphere of 30°C and 70% RH. ２The gas barrier properties were evaluated based on the following criteria: A: Oxygen permeability of 10 cc / m or less, and B: Oxygen permeability of 10 cc / m or less. ２ B: Oxygen permeability is less than 10 cc / m ２ ・Day・ATM or more.

[0209] (1.2.7) In-plane Measurement by X-ray Diffraction The substrate layer used in the production of the above laminate was subjected to in-plane measurement by X-ray diffraction as described above. It was examined whether a sharp diffraction peak corresponding to the (110) plane was obtained in the obtained diffraction pattern.

[0210] (1.3) Results The results of the above measurements and evaluations are shown in Table 1 below.

[0211]

[0212]

[0213] As shown in Table 1, all of the laminates in which the degree of molecular orientation of the base layer was 1.07 or more had good heat resistance and visibility. In contrast, all of the laminates in which the degree of molecular orientation of the base layer was less than 1.07 had insufficient heat resistance and visibility.

[0214] (2) Test B (2.1) Production of Laminate (2.1.0) Preparation of Coating Liquid (Preparation of Anchor Coating Agent) Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solids content (total amount of acrylic polyol and tolylene diisocyanate) was 5 mass%. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture so that the amount was 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coating agent.

[0215] (Preparation of Coating Liquid for Forming Covering Layer) The following liquids A, B, and C were mixed in a mass ratio of 70 / 20 / 10, respectively, to prepare a coating liquid for forming a covering layer. Liquid A: tetraethoxysilane (Si(OC ２ H ５ ) ４ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of SiO 2 and 10 g of methanol, and the mixture was stirred for 30 minutes to obtain a hydrolyzed solids content of 5% by mass (SiO ２ (equivalent) hydrolysis solution.

[0216] Solution B: a 5% by mass water / methanol solution of polyvinyl alcohol (water:methanol mass ratio 95:5).

[0217] Liquid C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate with a mixed liquid of water and isopropyl alcohol (water:isopropyl alcohol mass ratio 1:1) to a solids content of 5 mass %.

[0218] (Preparation of Coating Solution for Forming Protective Layer) An organic solvent-based coating solution containing polyamideimide (Viromax HR-15ET) manufactured by Toyobo Co., Ltd. was diluted with a mixed solvent of ethanol and toluene (ethanol / toluene mass ratio = 1 / 1) so that the non-volatile component concentration was 5 mass %, to prepare a coating solution for forming a protective layer.

[0219] (2.1.1) Example 1B A laminate was produced by the following method. The laminate produced here was a laminate in which, compared to laminate 10B shown in Fig. 2, an anchor coat layer was included between the base material layer 2 and the gas barrier layer 3, and the gas barrier layer 3 was composed of an inorganic compound layer and a coating layer.

[0220] First, the following film was prepared as the substrate layer 2. The prepared film was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.23, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, as measured by the above-mentioned method. ３ It is corona treated on one side.

[0221] After corona treatment was performed on one surface of the base layer 2, the above-mentioned protective layer forming coating liquid was applied by gravure coating and dried to form a protective layer 1 having a thickness of 0.5 μm.

[0222] Next, the above-mentioned anchor coating agent was applied by gravure coating to the corona-treated surface opposite to the base layer 2 to form an anchor coating layer having a thickness of 0.1 μm (in a dry state). Next, silicon oxide (SiO Ｘ ) An inorganic compound layer having a thickness of 40 nm composed of a vapor-deposited film was formed, and the above-mentioned coating liquid for forming a coating layer was further applied to form a coating layer having a thickness of 300 nm (in a dry state).

[0223] Next, a pattern was printed on the gas barrier layer 3 (coating layer) using gravure ink to form a printed layer 4 .

[0224] Next, a sealant layer 6 was prepared, and a urethane adhesive was applied onto the sealant layer 6 to form an adhesive layer 5. The printed layer 4 and the sealant layer 6 were then bonded together via the adhesive layer 5. A linear low-density polyethylene (LLDPE) film (thickness: 60 μm) was used as the material for the sealant layer 6. In this manner, the laminate according to Example 1B was produced.

[0225] (2.1.2) Example 2B A laminate according to Example 2B was produced in the same manner as the laminate according to Example 1B, except that the following film was used as the base layer 2. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0226] (2.1.3) Example 3B A laminate according to Example 3B was produced in the same manner as for the laminate according to Example 2B, except that the protective layer 1 was omitted.

[0227] (2.1.4) Example 4B A laminate according to Example 4B was produced in the same manner as in Example 1B, except that instead of applying a polyamideimide resin to form a protective layer having a thickness of 0.5 μm, the above-described coating solution for forming a covering layer was applied to form a protective layer having a thickness of 0.5 μm.

[0228] (2.1.5) Example 5B A laminate according to Example 5B was produced in the same manner as in Example 1B, except that instead of applying a polyamideimide resin to form a protective layer having a thickness of 0.5 μm, the above-described coating solution for forming a covering layer was applied to form a protective layer having a thickness of 1.0 μm.

[0229] (2.1.6) Example 6B A laminate according to Example 6B was produced in the same manner as in Example 1B, except that a urethane resin was applied to form a protective layer having a thickness of 0.5 μm, instead of applying a polyamideimide resin to form a protective layer having a thickness of 0.5 μm.

[0230] (2.1.7) Example 7B A laminate according to Example 7B was produced in the same manner as in Example 1B, except that instead of applying a polyamideimide resin to form a protective layer with a thickness of 0.5 μm, a urethane resin was applied to form a protective layer with a thickness of 1.0 μm.

[0231] (2.1.8) Example 8B A laminate according to Example 8B was produced in the same manner as in Example 1B, except that, instead of applying a polyamideimide resin to form a protective layer having a thickness of 0.5 μm, an ethylene-vinyl alcohol copolymer resin (EVOH) was applied to form a protective layer having a thickness of 1.0 μm.

[0232] (2.1.9) Example 9B A laminate according to Example 9B was produced in the same manner as in Example 1B, except that instead of applying a polyamideimide resin to form a protective layer with a thickness of 0.5 μm, an acrylic resin was applied to form a protective layer with a thickness of 1.0 μm.

[0233] (2.1.10) Comparative Example 1B A laminate according to Comparative Example 1B was produced in the same manner as the laminate according to Example 1B, except that the following film was used as the base layer 2 and protective layer 1 was omitted. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.04, a haze of 21.5%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0234] (2.2) Evaluation Methods The recyclability, heat resistance, and visibility of the laminate were evaluated. The evaluation methods for recyclability, heat resistance, and visibility are described below.

[0235] (2.2.1) Method for evaluating heat resistance at 140°C The above laminate was cut into a 10 cm x 10 cm sample piece. Next, the sample piece was folded so that the sealant layer 6 was on the inside, and the sample piece was heat-sealed. The heat sealing was performed by applying a temperature of 140°C and a pressure of 0.1 MPa to the sample piece for 1 second. The heat resistance of the sample piece was evaluated based on its appearance according to the following criteria: A: The surface was not melted, and there was no problem with the appearance. B: The surface was melted, and there was a problem with the appearance.

[0236] (2.2.2) Method for evaluating heat resistance at 170°C and 190°C The above laminate was cut into a 10 cm square to obtain a sample piece. Next, the sample piece was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was fixed at 30°C, and the top sealing temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample piece for 1 second. The presence or absence of melting of the sealed surface was then observed, and the area of ​​the top surface of the folded sample piece that was in contact with the heat seal bar was observed to see if it adhered to the heat seal bar. Heat resistance was evaluated based on the following evaluation criteria. A: The top surface of the sample piece did not adhere to the heat seal bar. B: The top surface of the sample piece adhered to the heat seal bar.

[0237] Furthermore, for the laminates having a protective layer, the heat resistance was further evaluated in the same manner as above, except that the top seal temperature was set to 190°C.

[0238] (2.2.3) Method for evaluating visibility For the above laminate, the pattern displayed by the printing layer 4 was visually observed from the protective layer 1 side, and visibility was evaluated according to the following criteria: A: The pattern displayed by the printing layer was clearly visible. B: The pattern displayed by the printing layer was blurred, unclear, and faint.

[0239] (2.2.4) Method for evaluating recyclability For the above laminates, the polyethylene (PE) content in the total mass of the laminate was calculated, and the recyclability was evaluated according to the following criteria: A: The polyethylene (PE) content is 90 mass% or more, and the monomaterial has excellent recyclability. B: The polyethylene (PE) content is less than 90 mass%.

[0240] (2.2.5) In-plane measurement by X-ray diffraction method The substrate layer used in the production of the above laminate was subjected to in-plane measurement by X-ray diffraction method as described above. It was examined whether a sharp diffraction peak corresponding to the (110) plane was obtained in the obtained diffraction pattern.

[0241] (2.3) Results The results of the above evaluations are shown in Table 2 below.

[0242]

[0243]

[0244] As shown in Table 2, all of the laminates in which the molecular orientation degree of the base layer was 1.07 or more had good heat resistance and visibility. Furthermore, the laminates in which the molecular orientation degree of the base layer was 1.07 or more and which had a protective layer were particularly excellent in heat resistance. In contrast, the laminates in which the molecular orientation degree of the base layer was less than 1.07 and which did not have a protective layer were insufficient in heat resistance and visibility.

[0245] (3) Test C (3.1) Production of Laminate (3.1.0) Preparation of Coating Liquid (Preparation of Anchor Coating Agent) Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solids content (total amount of acrylic polyol and tolylene diisocyanate) was 5 mass%. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture so that the amount was 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coating agent.

[0246] (Preparation of Coating Liquid for Forming Coating Layer) An overcoat agent was prepared by mixing the following liquids A, B, and C in a mass ratio of 70 / 20 / 10, respectively. Liquid A: tetraethoxysilane (Si(OC ２ H ５ ) ４ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of SiO 2 and 10 g of methanol, and the mixture was stirred for 30 minutes to obtain a hydrolyzed solids content of 5% by mass (SiO ２ Solution B: A 5% by mass water / methanol solution of polyvinyl alcohol (mass ratio of water:methanol is 95:5). Solution C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate with a water / isopropyl alcohol mixed solution (mass ratio of water:isopropyl alcohol is 1:1) to a solids content of 5% by mass.

[0247] (3.1.1) Example 1C The laminate 10C shown in FIG. 3 was produced by the following method. First, the following films were prepared as the substrate layer 2 and the intermediate layer 7. The prepared film was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, as measured by the above-mentioned method. ３ It is corona treated on one side.

[0248] Next, silicon oxide (SiO ) was deposited as the gas barrier layer 3 on one corona-treated surface of the intermediate layer 7 using an electron beam heating type vacuum deposition device. ｘ ) An inorganic compound layer having a thickness of 40 nm was formed by vapor deposition.

[0249] Next, a urethane adhesive was applied to the corona-treated surface of the base layer 2 to form a first adhesive layer 5A, and the intermediate layer 7 and the base layer 2 were bonded together.

[0250] Next, a sealant layer 6 was prepared, and a urethane adhesive for dry lamination was applied onto the sealant layer 6 to form a second adhesive layer 5B. The intermediate layer 7 and the sealant layer 6 were then bonded together via the second adhesive layer 5B. A linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) was used as the material for the sealant layer.

[0251] A pattern was printed using a water-based flexographic ink on the corona-treated surface of the intermediate layer 7 opposite to the gas barrier layer 3 to form a printed layer 4 .

[0252] In this way, a laminate according to Example 1C was produced. A schematic cross-sectional view of the laminate according to Example 1C is shown in FIG.

[0253] (3.1.2) Example 2C A laminate according to Example 2C was produced in the same manner as the laminate according to Example 1C, except that no inorganic compound layer was provided as the gas barrier layer 3.

[0254] (3.1.3) Example 3C A laminate according to Example 3C was produced in the same manner as the laminate according to Example 1C, except that a polyamine-based adhesive was used as the first adhesive layer 5A and the second adhesive layer 5B instead of a urethane-based adhesive.

[0255] (3.1.4) Example 4C A laminate according to Example 4C was produced in the same manner as the laminate according to Example 1C, except that the following film was used as the substrate layer 2. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.30, a haze of 4.1%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0256] (3.1.5) Example 5C A laminate according to Example 5C was produced in the same manner as the laminate according to Example 1C, except that the following film was used as the intermediate layer 7. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.02, a haze of 52.9%, a thickness of 40 μm, and a density of 0.949 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0257] (3.1.6) Comparative Example 1C A laminate according to Comparative Example 1C was produced in the same manner as the laminate according to Example 1C, except that the following film was used as the base layer 2. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.02, a haze of 52.9%, a thickness of 40 μm, and a density of 0.949 g / cm, measured by the method described above.３ It is corona treated on one side.

[0258] (3.1.7) Comparative Example 2C A laminate according to Comparative Example 2C was produced in the same manner as the laminate according to Example 1C, except that the following films were used as the substrate layer 2 and the intermediate layer 7. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.02, a haze of 52.9%, a thickness of 40 μm, and a density of 0.949 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0259] (3.2) Evaluation Methods The above laminates were evaluated for heat resistance, print visibility, gas barrier properties, and puncture strength. The evaluation methods for heat resistance, print visibility, gas barrier properties, and puncture strength are described below.

[0260] (3.2.1) Method for evaluating heat resistance at 140°C A sample piece of 10 cm square from the above laminate was cut out as a sample, folded in half with the sealant layer side facing inward, and heat-sealed using a heat seal tester at a temperature of 140°C, a pressure of 0.1 MPa, and a time of 1 second. The heat resistance, print visibility, gas barrier properties, and puncture strength of the sealed surface were evaluated as follows. The heat resistance of the sealed surface was evaluated visually. A: The surface was not melted and there was no problem with the appearance. B: The surface was melted and there was a problem with the appearance.

[0261] (3.2.2) Evaluation method for heat resistance at 170°C The above laminate was cut into a 10 cm square to obtain a sample piece. Next, the sample piece was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was fixed at 30°C, and the top sealing temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample piece for 1 second. The presence or absence of melting of the sealed surface was observed, and the area of ​​the top surface of the folded sample piece that was contacted with the heat seal bar was observed to see if it adhered to the heat seal bar. Heat resistance was evaluated based on the following evaluation criteria. A: The top surface of the sample piece did not adhere to the heat seal bar. B: The top surface of the sample piece adhered to the heat seal bar.

[0262] (3.2.3) Evaluation method for print visibility For the above laminate, the pattern displayed by the print layer 4 was visually observed from the substrate layer 2 side, and the visibility was evaluated according to the following criteria. A: The print pattern is clearly visible. B: The print pattern is blurred or appears faint. (3.2.4) Evaluation method for gas barrier properties For the above laminate, the oxygen permeability (cc / m) was measured in an atmosphere of 30°C and 70% RH. ２ The gas barrier properties were evaluated based on the following criteria: A: Oxygen permeability 10 cc / m or less; B: Oxygen permeability 10 cc / m or less; C: Oxygen permeability 10 cc / m or less; D: Oxygen permeability 10 cc / m or less; E: Oxygen permeability 10 cc / m or less; F ... ２ ・Less than day・atm B: Oxygen permeability 10cc / m ２ ・Day・ATM or more.

[0263] (3.2.5) Method for measuring puncture strength Each laminate film was pressed against the substrate side with a hemispherical needle having a radius of 0.5 mm at a speed of 50 mm / min, and the strength when punctured was measured (JIS Z 1707 puncture strength test).

[0264] (3.2.6) In-plane Measurement by X-ray Diffraction Method In-plane measurement by X-ray diffraction method was performed on each of the substrate layer and intermediate layer used in the production of the above laminate as described above. It was examined whether a sharp diffraction peak corresponding to the (110) plane was obtained in the obtained diffraction pattern.

[0265] (3.3) Results The results of the above evaluations are shown in Table 3 below.

[0266]

[0267] As shown in Table 3, all laminates in which the molecular orientation degree of the substrate layer was 1.07 or higher exhibited good heat resistance and print visibility. Furthermore, all laminates in which the molecular orientation degree of both the substrate layer and the intermediate layer was 1.07 or higher exhibited high puncture strength. In contrast, all laminates in which the molecular orientation degree of the substrate layer was less than 1.07 exhibited insufficient heat resistance and visibility. Furthermore, laminates in which the molecular orientation degree of both the substrate layer and the intermediate layer was less than 1.07 exhibited low puncture strength.

[0268] (4) Test D (4.1) Production of Laminate (4.1.0) Preparation of Coating Liquid (Preparation of Anchor Coating Agent) Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solids content (total amount of acrylic polyol and tolylene diisocyanate) was 5 mass%. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture so that the amount was 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coating agent.

[0269] (Preparation of Coating Liquid for Forming Cover Layer) The following liquids A, B, and C were mixed in a mass ratio of 70 / 20 / 10, respectively, to prepare a coating liquid for forming a cover layer.

[0270] Solution A: Tetraethoxysilane (Si(OC ２ H ５ ) ４ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of SiO 2 and 10 g of methanol, and the mixture was stirred for 30 minutes to obtain a hydrolyzed solids content of 5% by mass (SiO ２ Solution B: A 5% by mass water / methanol solution of polyvinyl alcohol (mass ratio of water:methanol is 95:5). Solution C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate with a water / isopropyl alcohol mixed solution (mass ratio of water:isopropyl alcohol is 1:1) to a solids content of 5% by mass.

[0271] (Coating liquid for forming protective layer) An organic solvent-based coating liquid (Viromax HR-15ET) containing polyamideimide manufactured by Toyobo Co., Ltd. was diluted with a mixed solvent of ethanol and toluene (ethanol / toluene mass ratio = 1 / 1) so that the non-volatile component concentration was 5 mass %, to prepare a coating liquid for forming a protective layer.

[0272] (4.1.1) Example 1D A laminate was produced by the following method. The laminate produced here was a laminate in which, compared to laminate 10D shown in Fig. 4, an anchor coat layer was included between the intermediate layer 7 and the gas barrier layer 3, and the gas barrier layer 3 was composed of an inorganic compound layer and a coating layer.

[0273] First, the following films were prepared as the base layer 2 and the intermediate layer 7. The prepared film was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.23, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, as measured by the above-mentioned method. ３ It is corona treated on one side.

[0274] Next, one surface of the base layer 2 was subjected to a corona treatment, and then the above-mentioned protective layer-forming coating liquid was applied by gravure coating and dried to form a 0.5 μm-thick protective layer 1. Next, a pattern was printed on the other corona-treated surface of the base layer 2 using a water-based flexographic ink to form a printed layer 4.

[0275] Next, one surface of the intermediate layer 7 was subjected to a corona treatment, and then the above-mentioned anchor coating agent was applied by gravure coating to form an anchor coating layer having a thickness of 0.1 μm (in a dry state). Next, silicon oxide (SiO Ｘ ) An inorganic compound layer having a thickness of 40 nm composed of a vapor-deposited film was formed, and the above-mentioned coating liquid for forming a coating layer was further applied to form a coating layer having a thickness of 300 nm (in a dry state).

[0276] Next, a urethane adhesive was applied onto the printed layer 4 to form a first adhesive layer 5A, and the intermediate layer 7 and the base material layer 2 were bonded together via the printed layer 4 and the first adhesive layer 5A.

[0277] Next, a sealant layer 6 was prepared, a urethane adhesive was applied onto the sealant layer 6 to form a second adhesive layer 5B, and the intermediate layer 7 and sealant layer 6 were bonded together via the gas barrier layer 3 and the second adhesive layer 5B. A linear low-density polyethylene resin (LLDPE) film (thickness 60 μm) was used as the material for the sealant layer.

[0278] In this way, the laminate according to Example 1D was produced.

[0279] (4.1.2) Example 2D A laminate according to Example 2D was produced in the same manner as the laminate according to Example 1D, except that the following films were used as the substrate layer 2 and the intermediate layer 7. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the above-mentioned method. ３ It is corona treated on one side.

[0280] (4.1.3) Example 3D A laminate according to Example 3D was produced in the same manner as the laminate according to Example 2D, except that protective layer 1 was not provided and the following film was used as intermediate layer 7. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.04, a haze of 21.5%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0281] (4.1.4) Comparative Example 1D A laminate according to Comparative Example 1D was produced in the same manner as the laminate according to Example 1D, except that the protective layer 1 was not provided and the following films were used as the base layer 2 and intermediate layer 7. The film used was made of polyethylene, and had a molecular orientation ratio (MOR) of 1.04, a haze of 21.5%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0282] (4.2) Measurement and Evaluation Methods The heat resistance, visibility, and recyclability of the laminate were evaluated. The puncture strength of the laminate was also measured. The methods for evaluating the heat resistance, visibility, and recyclability, and the method for measuring the puncture strength are described below.

[0283] (4.2.1) Method for evaluating heat resistance at 140°C The above laminate was cut into a 10 cm x 10 cm sample piece. Next, the sample piece was folded so that the sealant layer 6 was on the inside, and the sample piece was heat-sealed. The heat sealing was performed by applying a temperature of 140°C and a pressure of 0.1 MPa to the sample piece for 1 second. The heat resistance of the sample piece was evaluated based on its appearance according to the following criteria: A: The surface was not melted, and there was no problem with the appearance. B: The surface was melted, and there was a problem with the appearance.

[0284] (4.2.2) Method for evaluating heat resistance at 170°C and 190°C The above laminate was cut into a 10 cm square to obtain a sample piece. Next, the sample piece was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was fixed at 30°C, and the top sealing temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample piece for 1 second. The presence or absence of melting of the sealed surface was observed, and the area of ​​the top surface of the folded sample piece that was contacted with the heat seal bar was observed to see if it adhered to the heat seal bar. Heat resistance was evaluated based on the following evaluation criteria. A: The top surface of the sample piece did not adhere to the heat seal bar. B: The top surface of the sample piece adhered to the heat seal bar.

[0285] Furthermore, for the laminates having a protective layer, the heat resistance was further evaluated in the same manner as above, except that the top seal temperature was set to 190°C.

[0286] (4.2.3) Method for evaluating visibility For the above laminate, the pattern displayed by the printing layer 4 was visually observed from the protective layer 1 side, and visibility was evaluated according to the following criteria: A: The pattern displayed by the printing layer was clearly visible. B: The pattern displayed by the printing layer was blurred, unclear, and faint.

[0287] (4.2.4) Method for Measuring Puncture Strength The puncture strength (N) of the laminate was measured by the method described above.

[0288] (4.2.5) Evaluation of recyclability For the above laminates, the content of polyethylene (PE) in the total mass of the laminate was calculated, and the recyclability was evaluated according to the following criteria: A: The polyethylene (PE) content is 90 mass% or more, and the monomaterial has excellent recyclability. B: The polyethylene (PE) content is less than 90 mass%.

[0289] (4.2.6) In-plane Measurement by X-ray Diffraction Method In-plane measurement by X-ray diffraction method was performed on each of the substrate layer and intermediate layer used in the production of the above laminate as described above. It was examined whether a sharp diffraction peak corresponding to the (110) plane was obtained in the obtained diffraction pattern.

[0290] (4.3) Results The results of the above measurements and evaluations are shown in Table 4 below.

[0291]

[0292] As shown in Table 4, all laminates in which the molecular orientation degree of the substrate layer was 1.07 or more had good heat resistance and visibility. Furthermore, laminates in which the molecular orientation degree of the substrate layer was 1.07 or more and which had a protective layer were particularly excellent in heat resistance. Furthermore, all laminates in which the molecular orientation degree of both the substrate layer and the intermediate layer was 1.07 or more and which had a protective layer exhibited high puncture strength. In contrast, laminates in which the molecular orientation degree of the substrate layer was less than 1.07 had insufficient heat resistance and visibility. Furthermore, laminates in which the molecular orientation degree of both the substrate layer and the intermediate layer was less than 1.07 exhibited low puncture strength.

[0293] (5) Test E (5.1) Production of Laminate (5.1.1) Example 1E The laminate 10E shown in FIG. 5 was produced by the following method. First, the following film F1 was prepared as the substrate layer 2. The film F1 was made of polyethylene, and had a degree of molecular orientation of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm3, all measured by the above-mentioned method.３ It is corona treated on one side.

[0294] Next, the following film F2 was prepared as the intermediate layer 7. Film F2 was made of polyethylene, and had a degree of molecular orientation measured by the above-mentioned method of 1.02, a haze of 52.9%, a thickness of 40 μm, and a density of 0.949 g / cm ３ It is corona treated on one side.

[0295] Next, a layer made of silicon oxide was formed as the gas barrier layer 3 on the intermediate layer 7. The thickness of the gas barrier layer 3 was 50 nm.

[0296] Next, the printed layer 4 was formed on the base material layer 2. Next, a urethane adhesive was applied onto the printed layer 4 to form a first adhesive layer 5A, and the intermediate layer 7 and the base material layer 2 were bonded together with the first adhesive layer 5A and the gas barrier layer 3 interposed therebetween.

[0297] Next, a sealant layer 6 was prepared, and a urethane adhesive was applied onto the sealant layer 6 to form a second adhesive layer 5B. The intermediate layer 7 and the sealant layer 6 were then bonded together via the second adhesive layer 5B. Linear low-density polyethylene (LLDPE) was used as the material for the sealant layer. In this manner, a laminate according to Example 1E was produced.

[0298] (5.1.2) Example 2E A laminate according to Example 2E was produced in the same manner as the laminate according to Example 1E, except that a polyamine-based adhesive was used instead of a urethane-based adhesive as the material for the first adhesive layer 5A and the second adhesive layer 5B. This polyamine-based adhesive had gas barrier properties.

[0299] (5.1.3) Example 3E A laminate according to Example 3E was produced in the same manner as the laminate according to Example 1E, except that the substrate layer was made of the following film F3 and the intermediate layer was made of the following film F4. Film F3 was a longitudinally uniaxially stretched film made of high-density polyethylene. This film F3 had a molecular orientation degree of 1.30, a haze of 4.1, a thickness of 25 μm, and a density of 0.95 g / cm. ３The film F4 has a molecular orientation degree of 1.04, a haze of 21.5, a thickness of 25 μm, and a density of 0.950 g / cm. ３ It is corona treated on one side.

[0300] (5.1.4) Example 4E A laminate according to Example 4E was produced in the same manner as the laminate according to Example 1E, except that film F1 was used as the intermediate layer. Film F1 was made of polyethylene and had a molecular orientation degree of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0301] (5.1.5) Example 5E A laminate according to Example 5E was produced in the same manner as for the laminate according to Example 1E, except that the gas barrier layer was not provided.

[0302] (5.1.6) Comparative Example 1E A laminate according to Comparative Example 1E was produced in the same manner as the laminate according to Example 1E, except that film F2 was used as the substrate layer. Film F2 was made of polyethylene and had a molecular orientation degree of 1.02, a haze of 52.9%, a thickness of 40 μm, and a density of 0.949 g / cm, measured by the method described above. ３ It is corona treated on one side.

[0303] (5.1.7) Comparative Example 2E A laminate according to Comparative Example 2E was produced in the same manner as the laminate according to Example 1E, except that film F2 was used as the substrate layer and film F3 was used as the intermediate layer. Film F2 was made of polyethylene and had a degree of molecular orientation of 1.02, a haze of 52.9%, a thickness of 40 μm, and a density of 0.949 g / cm, measured by the method described above. ３ The film F3 is a longitudinally uniaxially stretched film made of high-density polyethylene, and is subjected to a corona treatment on one side. The film F3 has a molecular orientation degree of 1.30, a haze of 4.1, a thickness of 25 μm, and a density of 0.95 g / cm. ３ It is corona treated on one side.

[0304] (5.2) Evaluation Methods The above laminates were evaluated for heat resistance, visibility, drop strength, and gas barrier properties. However, the laminate of Example 5E was the only one that did not have a gas barrier layer, and therefore the gas barrier properties were not evaluated. The evaluation methods for heat resistance, visibility, drop strength, and gas barrier properties are described below.

[0305] (5.2.1) Evaluation method for heat resistance at 140°C First, the above laminate was cut into a 10 cm x 10 cm sample piece. Next, the sample piece was folded so that the sealant layer was on the inside, and the sample piece was heat-sealed. The heat sealing was performed by applying a temperature of 140°C and a pressure of 0.1 MPa to the sample piece for 1 second. Thereafter, the appearance of the sample piece was evaluated based on the following criteria: A: The base layer was not melted, and there was no problem with the appearance. B: The base layer was melted, and there was a problem with the appearance of the laminate.

[0306] (5.2.2) Evaluation Method for Heat Resistance at 170°C The above laminate was cut into a 10 cm square to obtain a sample piece. Next, the sample piece was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was fixed at 30°C, and the top sealing temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample piece for 1 second. The presence or absence of melting of the sealed surface was observed, and the area of ​​the top surface of the folded sample piece that was in contact with the heat seal bar was observed to see if it adhered to the heat seal bar. Heat resistance was evaluated based on the following evaluation criteria. A: The top surface of the sample piece did not adhere to the heat seal bar. B: The top surface of the sample piece adhered to the heat seal bar.

[0307] (5.2.3) Method for evaluating visibility When the above laminate was observed from the base layer side, the pattern displayed by the printing layer was evaluated based on the following criteria to determine whether it was clearly visible. A: The pattern displayed by the printing layer was clearly visible. B: The pattern displayed by the printing layer was blurred and faint.

[0308] (5.2.4) Evaluation Method for Drop Strength First, 10 packages were prepared using the above laminate. An opening for accommodating the contents was provided in each package. The dimensions of the package were 100 mm x 150 mm. Next, 200 ml of tap water was filled into each package, and the opening of the package was heat-sealed to obtain a packaged article. Next, each packaged article was stored at 5°C for 1 day, and then dropped 50 times from a height of 1.5 m to evaluate whether the packaged article was broken or not.

[0309] The evaluation results are expressed as the ratio of the number of packaged articles that were broken due to dropping to the total number of packaged articles produced.

[0310] (5.2.5) Evaluation Method of Gas Barrier Properties The oxygen transmission rate (OTR) of the above laminate was measured at 30°C and a relative humidity of 70%, and the value was 10 cc / (m ２ The gas barrier properties were evaluated based on whether the oxygen permeability exceeded 10 cc / (m. ·day·atm). The oxygen permeability was measured according to the method described in Appendix B of JIS K7126-2:2006. A: The oxygen permeability was 10 cc / (m ２ B: Oxygen permeability was less than 10 cc / (m ２ ・day・atm) or more.

[0311] (5.2.6) In-plane Measurement by X-ray Diffraction Method In-plane measurement by X-ray diffraction method was performed on each of the substrate layer and intermediate layer used in the production of the above laminate as described above. It was examined whether a sharp diffraction peak corresponding to the (110) plane was obtained in the obtained diffraction pattern.

[0312] (5.3) Results The results of the above evaluations are shown in Table 5 below.

[0313]

[0314] As shown in Table 5, all of the laminates having a molecular orientation degree of 1.07 or more in the base layer had good heat resistance and visibility. Furthermore, laminates having a molecular orientation degree of 1.07 or more in the base layer and a molecular orientation degree of 1.07 or less in the intermediate layer had excellent drop strength. In contrast, all of the laminates having a molecular orientation degree of less than 1.07 in the base layer had insufficient heat resistance and visibility.

[0315] (6) Test F (6.1) Production of Laminate (6.1.0) Preparation of Coating Liquid (Preparation of Anchor Coating Agent) Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solids content (total amount of acrylic polyol and tolylene diisocyanate) was 5 mass%. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture so that the amount was 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coating agent.

[0316] (Preparation of Coating Liquid for Forming Coating Layer) The following liquids A, B, and C were mixed in a mass ratio of 70 / 20 / 10, respectively, to prepare an overcoat agent.

[0317] Solution A: Tetraethoxysilane (Si(OC ２ H ５ ) ４ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of SiO 2 and 10 g of methanol, and the mixture was stirred for 30 minutes to obtain a hydrolyzed solids content of 5% by mass (SiO ２ Solution B: A 5% by mass water / methanol solution of polyvinyl alcohol (mass ratio of water:methanol is 95:5). Solution C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate with a water / isopropyl alcohol mixed solution (mass ratio of water:isopropyl alcohol is 1:1) to a solids content of 5% by mass.

[0318] (Coating Solution for Forming Protective Layer) An organic solvent-based coating solution containing polyamideimide (Viromax (registered trademark) HR-15ET) manufactured by Toyobo Co., Ltd. was diluted with a solvent (ethanol / toluene = 1 / 1) so that the non-volatile component concentration was 5 mass % to prepare a coating solution for forming a protective layer.

[0319] (6.1.1) Example 1F A laminate 10F shown in FIG. 6 was produced by the following method. First, the following film F11 was prepared as the base layer 2. The film F11 was made of polyethylene, had a molecular orientation ratio (MOR) of 1.23 measured by the above-mentioned method, a thickness of 25 μm, and a density of 0.950 g / cm. ３ It is corona treated on one side.

[0320] Next, one surface of the base layer 2 was subjected to a corona treatment, and then the coating liquid for forming the protective layer described above was applied by gravure coating and dried to form a protective layer having a thickness of 0.5 μm.

[0321] Next, the surface opposite to the base layer 2 was subjected to a corona treatment, and a pattern was printed using a water-based flexographic ink to form a print layer 4 .

[0322] Next, the following film F12 was prepared as the intermediate layer 7. The film F12 was made of polyethylene, had a molecular orientation degree of 1.04, a thickness of 25 μm, and a density of 0.950 g / cm ３ It is corona treated on one side.

[0323] Next, on the intermediate layer 7, a silicon oxide (SiO ｘ ) An inorganic compound layer having a thickness of 40 nm was formed by vapor deposition, and then an organic-inorganic coating mixture liquid was applied to form a coating layer having a thickness of 0.3 μm.

[0324] Next, a urethane adhesive was applied onto the printed layer 4 to form a first adhesive layer 5A, and the intermediate layer 7 and the base material layer 2 were bonded together via the printed layer 4 and the first adhesive layer 5A.

[0325] Next, a sealant layer 6 was prepared, and a urethane adhesive was applied onto the gas barrier layer 3 to form a second adhesive layer 5B. The intermediate layer 7 and the sealant layer 6 were then bonded together via the gas barrier layer 3 and the second adhesive layer 5B. Linear low-density polyethylene (LLDPE) was used as the material for the sealant layer. In this manner, the laminate of Example 1F was produced.

[0326] (6.1.2) Example 2F A laminate according to Example 2F was produced in the same manner as the laminate according to Example 1F, except that the following film F13 was used as the base layer 2. Film F13 was made of polyethylene, and had a degree of molecular orientation of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the above-mentioned method. ３ It is corona treated on one side.

[0327] (6.1.3) Example 3F A laminate according to Example 3F was produced in the same manner as the laminate according to Example 1F, except that film F13 was used as the base layer 2, film F14 was used as the intermediate layer 7, and protective layer 1 was omitted. Film F13 was made of polyethylene, and had a degree of molecular orientation of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm, measured by the method described above. ３ Film F14 is made of polyethylene, has a degree of molecular orientation measured by the above-mentioned method of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm ３ It is corona treated on one side.

[0328] (6.1.4) Example 4F A laminate according to Example 4F was produced in the same manner as for the laminate according to Example 1F, except that the protective layer 1 was omitted.

[0329] (6.1.5) Comparative Example 1F A laminate according to Comparative Example 1F was produced in the same manner as the laminate according to Example 1F, except that film F12 was used as the base layer 2, film F14 was used as the intermediate layer 7, and protective layer 1 was omitted. Film F12 was made of polyethylene, had a molecular orientation degree of 1.04, a thickness of 25 μm, and a density of 0.950 g / cm ３ Film F14 is made of polyethylene, has a degree of molecular orientation measured by the above-mentioned method of 1.30, a haze of 1.6%, a thickness of 25 μm, and a density of 0.950 g / cm ３ It is corona treated on one side.

[0330] (6.1.6) Comparative Example 2F A laminate according to Comparative Example 2F was produced in the same manner as the laminate according to Example 1F, except that film F12 was used as the base layer 2 and protective layer 1 was omitted. Film F12 was made of polyethylene, had a molecular orientation degree of 1.04, a thickness of 25 μm, and a density of 0.950 g / cm ３ It is corona treated on one side.

[0331] (6.2) Evaluation Methods The above laminates were evaluated for heat resistance, visibility, drop strength, and recyclability. The evaluation methods for heat resistance, visibility, drop strength, and recyclability are described below.

[0332] (6.2.1) Evaluation method for heat resistance at 140°C First, the above laminate was cut into a 10 cm x 10 cm sample piece. Next, the sample piece was folded so that the sealant layer was on the inside, and the sample piece was heat-sealed. Heat sealing was performed by applying a temperature of 140°C and a pressure of 0.1 MPa to the sample piece using a heat seal tester for 1 second. Thereafter, the appearance of the sample piece was evaluated based on the following criteria: A: The surface was not melted, and there was no problem with the appearance. B: The surface was melted, and there was a problem with the appearance of the laminate.

[0333] (6.2.2) Method for Evaluating Heat Resistance at 170°C and 190°C The above laminate was cut into a 10 cm square to obtain a sample piece. Next, the sample piece was folded in half with the sealant layer facing inward. Next, the bottom sealing temperature of the heat seal tester was fixed at 30°C, and the top sealing temperature was set to 170°C, and a pressure of 0.2 MPa was applied to the folded sample piece for 1 second. The presence or absence of melting of the sealed surface was observed, and the area of ​​the top surface of the folded sample piece that was contacted with the heat seal bar was observed to see if it adhered to the heat seal bar. Heat resistance was evaluated based on the following evaluation criteria. A: The top surface of the sample piece did not adhere to the heat seal bar. B: The top surface of the sample piece adhered to the heat seal bar.

[0334] Furthermore, for the laminates having a protective layer, the heat resistance was further evaluated in the same manner as above, except that the top seal temperature was set to 190°C.

[0335] (6.2.3) Method for evaluating visibility The image on the laminate was visually observed through the substrate from the side opposite to the side on which the ink layer was formed, and a sensory evaluation was performed. The evaluation was categorized into the following two levels: A: The image was clearly visible. B: The image appeared cloudy.

[0336] (6.2.4) Evaluation Method for Drop Strength First, 10 bags were prepared as packages using the above laminate. An opening for accommodating the contents was provided in the package. The dimensions of the package were 100 mm x 150 mm. Next, 200 ml of tap water was filled into each package, and the opening of the package was heat-sealed to obtain a packaged article. Next, each packaged article was stored at 5°C for 1 day, and then dropped 50 times from a height of 1.5 m to evaluate whether the packaged article was broken.

[0337] The evaluation results are expressed as the ratio of the number of packaged articles whose packaging was broken when dropped to the total number of packaged articles produced.

[0338] (6.2.5) Method for evaluating recyclability For the above laminates, the proportion of polyethylene in the total mass of the laminate was calculated, and the recyclability was evaluated according to the following criteria: A: The proportion of polyethylene in the laminate is 90 mass% or more. B: The proportion of polyethylene in the laminate is less than 90 mass%.

[0339] (6.2.6) In-plane Measurement by X-ray Diffraction Method In-plane measurement by X-ray diffraction method was performed on each of the substrate layers and intermediate layers used in the production of the above laminates as described above. It was examined whether a sharp diffraction peak corresponding to the (110) plane was obtained in the obtained diffraction pattern.

[0340] (6.3) Results The results of the above evaluations are shown in Table 6 below.

[0341]

[0342] As shown in Table 6, all laminates having a molecular orientation degree of 1.07 or more in the base layer had good heat resistance and visibility. Furthermore, laminates having a base layer with a molecular orientation degree of 1.07 or more and a protective layer were particularly excellent in heat resistance. Furthermore, laminates having a base layer with a molecular orientation degree of 1.07 or more and an intermediate layer with a molecular orientation degree of 1.07 or less were excellent in drop strength. In contrast, all laminates having a base layer with a molecular orientation degree of less than 1.07 had insufficient heat resistance and visibility.

[0343] DESCRIPTION OF SYMBOLS 1...protective layer, 2...substrate layer, 3...gas barrier layer, 4...printed layer, 5...adhesive layer, 5A...first adhesive layer, 5B...second adhesive layer, 6...sealant layer, 7...intermediate layer, 10A...laminate, 10B...laminate, 10C...laminate, 10D...laminate, 10E...laminate, 10F...laminate, 100A...packaged article, 100B...packaged article, 100C...packaged article, 110A...packaged body, 110B...packaged body, 110C...packaged body, 110C1...container body, 110C2...mouth member, 110C3...lid body

Claims

1. a substrate layer, an adhesive layer, and a sealant layer in this order; the substrate layer and the sealant layer comprise polyethylene; The substrate layer has a degree of molecular orientation of 1.07 or more as an absolute value measured by a microwave method.

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

3. 3. The laminate according to claim 2, wherein the absolute value of the degree of molecular orientation of the intermediate layer measured by a microwave method is 1.07 or less.

4. 3. The laminate according to claim 2, wherein the absolute value of the degree of molecular orientation of the intermediate layer measured by a microwave method is 1.07 or more.

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

6. The laminate according to claim 5 , wherein the protective layer is made of a thermosetting resin.

7. The laminate 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 interposed between the base layer and the sealant layer.

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

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

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

13. A package comprising a laminate according to any one of claims 1 to 12.

14. 14. The package according to claim 13, which is a stand-up pouch.

15. A packaged article comprising the package of claim 13 and contents contained therein.