Laminate

Abstract

To provide a laminate excellent in a COreduction effect while having designability.SOLUTION: A laminate at least includes a first oriented plastic film 11, a second oriented plastic film 12 and a sealant layer 15 in this order. A packaging material 10 further includes a metal deposition layer 22 formed on the second oriented plastic film 12. At least one of the first oriented plastic film 11 and the second oriented plastic film 12 has ethylene glycol as a diol unit, and includes polyethylene terephthalate having terephthalic acid and isophthalic acid as a dicarboxylic acid unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate. [Background technology]

[0002] Bags made of flexible packaging materials are used to store fluid contents such as liquids and powders. The shape of the bag is determined by a seal formed by heat-sealing the flexible packaging material.

[0003] The packaging material constituting the flexible packaging material is composed of a laminate including a substrate and a sealant layer that is laminated on the substrate and melts by heat sealing. The layer structure of the laminate is determined, for example, from the viewpoint of mechanical strength. For example, in Patent Document 1, the substrate is composed of nylon and the sealant layer is composed of polyethylene. Nylon contributes to improving the mechanical strength of the laminate, such as puncture resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-218204 Summary of the Invention [Problem to be solved by the invention]

[0005] Materials made from petroleum, a fossil resource, have traditionally been used to make the substrate of laminates. In recent years, there has been a growing trend toward reducing the use of fossil fuels in various applications and reducing CO2 emissions in consideration of the environment.

[0006] An object of the present invention is to provide a laminate that can effectively solve these problems. [Means for solving the problem]

[0007] The present invention is a laminate comprising at least a first stretched plastic film, a second stretched plastic film, and a sealant layer, in this order, wherein the laminate further comprises a metal vapor deposition layer provided on the second stretched plastic film, and at least one of the first stretched plastic film or the second stretched plastic film comprises polyethylene terephthalate having ethylene glycol as the diol unit and terephthalic acid and isophthalic acid as the dicarboxylic acid units.

[0008] In the laminate according to the present invention, the second stretched plastic film may contain polyethylene terephthalate having ethylene glycol as the diol unit and terephthalic acid and isophthalic acid as the dicarboxylic acid unit.

[0009] In the laminate according to the present invention, the first stretched plastic film may contain polyethylene terephthalate having ethylene glycol as the diol unit and terephthalic acid and isophthalic acid as the dicarboxylic acid unit.

[0010] In the laminate according to the present invention, the first stretched plastic film may contain polypropylene.

[0011] In the laminate according to the present invention, the first stretched plastic film comprises a rigid film, and the rigid film may comprise polyamide, or may comprise polybutylene terephthalate, or may have a loop stiffness of 0.0017 N or more in one direction and may comprise polyester.

[0012] In the laminate according to the present invention, the sealant layer may have a thickness of 18 μm or more and 120 μm or less.

[0013] In the laminate according to the present invention, the polyethylene terephthalate may have an intrinsic viscosity of 0.58 dL / g or more and 0.80 dL / g or less.

[0014] In the laminate according to the present invention, the Young's modulus of the laminate in one direction may be 3200 MPa or more. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a laminate that is excellent in CO2 reduction effect and also has designability. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view showing an example of a packaging material according to the present embodiment. [Figure 2] 1 is a schematic cross-sectional view showing an example of a packaging material according to the present embodiment. [Figure 3] 1 is a schematic cross-sectional view showing an example of a packaging material according to the present embodiment. [Figure 4] 1 is a schematic cross-sectional view showing an example of a packaging material according to the present embodiment. [Figure 5] FIG. 1 is a schematic cross-sectional view showing an example of a recycled film. [Figure 6] FIG. 1 is a plan view showing an example of a loop stiffness measuring device. [Figure 7] FIG. 7 is a cross-sectional view of the loop stiffness measuring device of FIG. 6 taken along line VI-VI. [Figure 8] FIG. 10 is a diagram illustrating a process of attaching a test piece to a loop stiffness measuring instrument. [Figure 9] FIG. 10 is a diagram illustrating a step of forming a loop portion in a test piece. [Figure 10] FIG. 10 is a diagram illustrating a process of applying a load to a loop portion of a test piece. [Figure 11] FIG. 10 is a diagram illustrating a process of applying a load to a loop portion of a test piece. [Figure 12] FIG. 1 is a schematic front view showing an example of a packaging bag. [Figure 13] FIG. 1 is a schematic front view showing an example of a packaging bag. [Figure 14] FIG. 10 is a diagram showing an example of a method for measuring puncture strength. DETAILED DESCRIPTION OF THE INVENTION

[0017] <Laminates (packaging materials)> The laminate according to this embodiment comprises at least a first stretched plastic film, a second stretched plastic film, and a sealant layer, in this order. The laminate may further comprise other layers such as an adhesive layer, a printed layer, a metal deposition layer, etc. In this embodiment, an example will be described in which the laminate is used as a packaging material for forming a bag.

[0018] The packaging material according to the present embodiment will be described with reference to the drawings. Examples of schematic cross-sectional views of the packaging material according to the present embodiment are shown in Figures 1 to 4.

[0019] The packaging material 10 shown in FIG. 1 includes, in this order, a first stretched plastic film 11, a printed layer 21, a first adhesive layer 16, a metal vapor deposition layer 22, a second stretched plastic film 12, a second adhesive layer 17, and a sealant layer 15. In a packaging bag including the packaging material 10 shown in FIG. 1 and FIGS. 2 to 4 described below, the sealant layer 15 forms the inner surface of the packaging bag. In the example shown in FIG. 1, the sealant layer 15 is formed by laminating a film constituting the sealant layer onto the second stretched plastic film 12. In the example shown in FIG. 1, the first adhesive layer 16 and the second adhesive layer 17 are adhesive layers described below. In the examples shown in FIG. 1 and FIGS. 2 to 4 described below, the metal vapor deposition layer 22 may be provided on the outer surface of the second stretched plastic film 12, or on the inner surface of the second stretched plastic film 12.

[0020] The packaging material 10 shown in Fig. 2 comprises, in this order, a first stretched plastic film 11, a printed layer 21, a first anchor coat layer 18, a first adhesive layer 16, a metal vapor deposition layer 22, a second stretched plastic film 12, a second anchor coat layer 19, a second adhesive layer 17, and a sealant layer 15. In the example shown in Fig. 1, the sealant layer 15 is formed by laminating a film constituting the sealant layer onto the second stretched plastic film 12. In the example shown in Fig. 2, the first adhesive layer 16 and the second adhesive layer 17 are adhesive resin layers, which will be described later.

[0021] The packaging material 10 shown in Fig. 3 comprises, in this order, a first stretched plastic film 11, a printed layer 21, a first adhesive layer 16, a metal vapor deposition layer 22, a second stretched plastic film 12, a second anchor coat layer 19, and a sealant layer 15. In the example shown in Fig. 3, the sealant layer 15 is formed by molding a material constituting the sealant layer onto the second stretched plastic film 12. In the example shown in Fig. 3, the first adhesive layer 16 is an adhesive layer, which will be described later.

[0022] The packaging material 10 shown in Fig. 4 comprises, in this order, a first stretched plastic film 11, a printed layer 21, a first anchor coat layer 18, a first adhesive layer 16, a metal vapor deposition layer 22, a second stretched plastic film 12, a second anchor coat layer 19, and a sealant layer 15. In the example shown in Fig. 4, the sealant layer 15 is formed by molding a material constituting the sealant layer onto the second stretched plastic film 12. In the example shown in Fig. 4, the first adhesive layer 16 is an adhesive resin layer, which will be described later.

[0023] The films and layers that make up packaging material 10 are described below.

[0024] [Stretched plastic film] Both the first stretched plastic film 11 and the second stretched plastic film 12 are plastic films stretched in a predetermined direction. Each of the stretched plastic films 11, 12 may be a uniaxially stretched film stretched in one predetermined direction, or a biaxially stretched film stretched in two predetermined directions. The stretching direction of each of the stretched plastic films 11, 12 is not particularly limited. For example, the stretched plastic films 11, 12 may be stretched in the height direction of the packaging bag formed from the packaging material 10, or may be stretched in the width direction of the packaging bag. The stretching directions of the stretched plastic films 11, 12 may be the same or different. The stretching ratio of each of the stretched plastic films 11, 12 is, for example, 1.05 times or more.

[0025] At least one of the first stretched plastic film 11 and the second stretched plastic film 12 is a recycled film containing recycled PET. For example, the first stretched plastic film 11 may be a recycled film, and the second stretched plastic film 12 may be a recycled film. In this case, the stretched plastic film that is not the recycled film, either the first stretched plastic film 11 or the second stretched plastic film 12, is a virgin film containing PET derived from fossil fuels, a stretched polypropylene film containing polypropylene (hereinafter also referred to as OPP film), or a rigid film having rigidity. Furthermore, both the first stretched plastic film 11 and the second stretched plastic film 12 may be recycled films.

[0026] Examples of combinations of the first stretched plastic film 11 and the second stretched plastic film 12 made of the above-mentioned recycled film, virgin film, OPP film, rigid film, etc. are shown in Table 1. In Examples 1 to 7, the metal vapor deposition layer 22 may be facing the outer surface of the second stretched plastic film 12, or may be provided on the inner surface of the second stretched plastic film 12. [Table 1]

[0027] The recycled film, rigid film, virgin film and OPP film will be explained below.

[0028] (recycled film) The recycled film contains polyethylene terephthalate (hereinafter, polyethylene terephthalate will also be referred to as PET) recycled by mechanical recycling. Specifically, the recycled film contains PET mechanically recycled from PET bottles, where the diol unit is ethylene glycol and the dicarboxylic acid units are terephthalic acid and isophthalic acid. Mechanical recycling generally refers to a process in which collected polyethylene terephthalate resin products, such as PET bottles, are crushed and washed with alkali to remove surface contamination and foreign matter from the PET resin product, and then dried at high temperature and reduced pressure for a certain period of time to diffuse contaminants remaining inside the PET resin, thereby decontaminating the PET resin product and returning it to PET resin. Hereinafter, in this specification, polyethylene terephthalate recycled from PET bottles will be referred to as "recycled polyethylene terephthalate (hereinafter, also referred to as recycled PET)," and unrecycled polyethylene terephthalate will be referred to as "virgin polyethylene terephthalate (hereinafter, also referred to as virgin PET)."

[0029] The content of isophthalic acid in the PET contained in the recycled film is preferably 0.5 mol% to 5 mol% and more preferably 1.0 mol% to 2.5 mol% relative to the total dicarboxylic acid units constituting the PET. If the isophthalic acid content is less than 0.5 mol%, flexibility may not be improved, while if it exceeds 5 mol%, the melting point of the PET may decrease, resulting in insufficient heat resistance. The PET may be a conventional PET derived from fossil fuels or a biomass PET. "Biomass PET" refers to a PET containing biomass-derived ethylene glycol as the diol unit and a fossil fuel-derived dicarboxylic acid as the dicarboxylic acid unit. This biomass PET may be formed solely from PET containing biomass-derived ethylene glycol as the diol unit and fossil fuel-derived dicarboxylic acid as the dicarboxylic acid unit, or it may be formed from PET containing biomass-derived ethylene glycol and fossil fuel-derived diol as the diol unit and a fossil fuel-derived dicarboxylic acid as the dicarboxylic acid unit.

[0030] The PET used for PET bottles can be obtained by a conventionally known method of polycondensing the above-mentioned diol units and dicarboxylic acid units. Specifically, it can be produced by a general melt polymerization method in which the above-mentioned diol units and dicarboxylic acid units are subjected to an esterification reaction and / or transesterification reaction, followed by a polycondensation reaction under reduced pressure, or by a known solution heating dehydration condensation method using an organic solvent.

[0031] The amount of diol units used in producing the above-mentioned PET is substantially equimolar to 100 moles of dicarboxylic acid or its derivative, but is generally used in an excess of 0.1 mol % to 20 mol % because distillates are generated during the esterification and / or transesterification reaction and / or polycondensation reaction.

[0032] The polycondensation reaction is preferably carried out in the presence of a polymerization catalyst. The timing of adding the polymerization catalyst is not particularly limited as long as it is before the polycondensation reaction, and the catalyst may be added when the raw materials are charged or when pressure reduction is initiated.

[0033] After the PET recycled from PET bottles has been polymerized and solidified as described above, it may be subjected to solid-state polymerization as necessary to further increase the degree of polymerization or to remove oligomers such as cyclic trimers. Specifically, the solid-state polymerization is carried out by cutting the PET into chips, drying it, heating it at a temperature of 100°C to 180°C for about 1 to 8 hours to pre-crystallize the PET, and then heating it at a temperature of 190°C to 230°C in an inert gas atmosphere or under reduced pressure for 1 hour to several tens of hours.

[0034] The intrinsic viscosity of the PET contained in the recycled film is preferably 0.58 dL / g or more and 0.80 dL / g or less. If the intrinsic viscosity is less than 0.58 dL / g, the mechanical properties required for the PET film as a substrate may be insufficient. On the other hand, if the intrinsic viscosity exceeds 0.80 dL / g, productivity in the film production process may be impaired. The intrinsic viscosity is measured in an orthochlorophenol solution at 35°C.

[0035] The recycled film preferably contains recycled PET in a proportion of 50% by weight or more and 95% by weight or less, and may contain virgin PET in addition to recycled PET. The PET content in the recycled film may be 80% by weight or more, 90% by weight or more, or even 95% by weight or more. The virgin PET may be a PET in which the diol unit is ethylene glycol and the dicarboxylic acid unit contains terephthalic acid and isophthalic acid, as described above, or a PET in which the dicarboxylic acid unit does not contain isophthalic acid. The recycled film may also contain polyesters other than PET. For example, the dicarboxylic acid unit may contain aliphatic dicarboxylic acids in addition to aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid.

[0036] Specific examples of aliphatic dicarboxylic acids include linear or alicyclic dicarboxylic acids typically having 2 to 40 carbon atoms, such as oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, and cyclohexanedicarboxylic acid. Derivatives of aliphatic dicarboxylic acids include lower alkyl esters of the above aliphatic dicarboxylic acids, such as methyl esters, ethyl esters, propyl esters, and butyl esters, and cyclic acid anhydrides of the above aliphatic dicarboxylic acids, such as succinic anhydride. Among these, preferred aliphatic dicarboxylic acids are adipic acid, succinic acid, dimer acid, or mixtures thereof, with those primarily composed of succinic acid being particularly preferred. More preferred derivatives of aliphatic dicarboxylic acids are methyl esters of adipic acid and succinic acid, or mixtures thereof.

[0037] Such recycled films made of PET may be single-layer or multi-layer. FIG. 5 is a cross-sectional view showing an example of a recycled film 30. The recycled film 30 shown in FIG. 5 has three layers: a first layer 31, a second layer 32, and a third layer 33. The third layer 33 is located on the sealant layer 15 side of the packaging material 10. In the example shown in FIG. 5, the second layer 32 is preferably a layer made solely of recycled PET or a mixed layer of recycled PET and virgin PET, and the first layer 31 and the third layer 33 are preferably layers made solely of virgin PET. Using only virgin PET for the first layer 31 and the third layer 33 in this way prevents the recycled PET from appearing on the front or back surface of the recycled film 30. This ensures the hygienic properties of the packaging material 10. Alternatively, the recycled film 30 may have two layers: the second layer 32 and the third layer 33, without the first layer 31 shown in FIG. 5. Furthermore, the recycled film 30 may have two layers, a first layer 31 and a second layer 32, without having the third layer 33 shown in Fig. 5. Even in these cases, it is preferable that the second layer 32 be a layer made only of recycled PET or a mixed layer of recycled PET and virgin PET, and that the first layer 31 and the third layer 33 be layers made only of virgin PET.

[0038] When recycled PET and virgin PET are mixed to form a single layer, they may be fed separately to a molding machine, or they may be mixed by dry blending or the like and then fed. Of these, the dry blending method is preferred from the viewpoint of ease of operation.

[0039] Various additives can be added to the PET that constitutes the recycled film during or after its production, provided that the film's properties are not impaired. Examples of additives include plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, mold release agents, antioxidants, ion exchange agents, and color pigments. The additives are preferably added in an amount of 5% by mass to 50% by mass, and more preferably 5% by mass to 20% by mass, based on the total mass of the resin composition containing PET.

[0040] The recycled film can be formed by using the above-mentioned PET to form a film, for example, by a T-die method. Specifically, after drying the above-mentioned PET, the resin composition is supplied to a melt extruder heated to a temperature above the melting point of PET (Tm) to Tm + 70°C, melted, and extruded into a sheet form through a die such as a T-die. The extruded sheet can be rapidly cooled and solidified using a rotating cooling drum or the like to form a film. As the melt extruder, a single-screw extruder, a twin-screw extruder, a vent extruder, a tandem extruder, or the like can be used depending on the purpose.

[0041] The film obtained as described above is preferably biaxially stretched. Biaxial stretching can be performed by a conventionally known method. For example, the film extruded onto the cooling drum as described above is subsequently heated by roll heating, infrared heating, or the like, and stretched in the longitudinal direction to form a longitudinally stretched film. This stretching is preferably performed by utilizing the difference in peripheral speed between two or more rolls. The longitudinal stretching is usually performed at a temperature range of 50°C or higher and 100°C or lower. The longitudinal stretching ratio is preferably 2.5 times or higher and 4.2 times or lower, depending on the required properties of the film application. If the stretching ratio is less than 2.5 times, the thickness unevenness of the PET film becomes large, making it difficult to obtain a good film.

[0042] The longitudinally stretched film is then subjected to the sequential processes of transverse stretching, heat setting, and heat relaxation to become a biaxially stretched film. Transverse stretching is usually carried out at a temperature ranging from 50°C to 100°C. The transverse stretching ratio is preferably 2.5 times to 5.0 times, depending on the required properties of the application. If the ratio is less than 2.5 times, the film thickness will become uneven, making it difficult to obtain a good film, and if the ratio is more than 5.0 times, breakage will occur during film formation.

[0043] After transverse stretching, heat setting is carried out. The preferred temperature range for heat setting is Tg+70 to Tm-10°C of PET. The heat setting time is preferably 1 second or more and 60 seconds or less. For applications requiring a reduction in heat shrinkage, heat relaxation treatment may be carried out as necessary.

[0044] The thickness of the recycled film obtained as described above is optional depending on its application, but is usually about 5 μm or more and 100 μm or less, preferably 5 μm or more and 25 μm or less. The breaking strength of the recycled film is 5 kg / mm ​​in the MD direction. 2 More than 40kg / mm 2 Below, 5 kg / mm ​​in the TD direction 2 More than 35kg / mm 2 The elongation at break is 50% to 350% in the MD direction and 50% to 300% in the TD direction. The shrinkage when left in a 150°C temperature environment for 30 minutes is 0.1% to 5%.

[0045] Virgin PET may be fossil fuel polyethylene terephthalate (hereinafter also referred to as fossil fuel PET) or biomass PET. Here, "fossil fuel PET" refers to PET in which a diol derived from a fossil fuel is used as a diol unit and a dicarboxylic acid derived from a fossil fuel is used as a dicarboxylic acid unit. Recycled PET may be obtained by recycling a PET resin product formed using fossil fuel PET, or may be obtained by recycling a PET resin product formed using biomass PET.

[0046] (rigid film) The rigid film is a film that provides strength such as puncture resistance to the packaging material 10. As the rigid film, any of the following stretched plastic films (1) to (3) can be used. (1) Stretched plastic film containing polyamide as the main component (hereinafter also referred to as polyamide film) (2) Stretched plastic film containing polybutylene terephthalate (hereinafter also referred to as PBT film) as the main component (3) A stretched plastic film having a loop stiffness of 0.0017 N or more in at least one direction and containing polyester as the main component (hereinafter also referred to as a high-stiffness film). By using any of the stretched plastic films (1) to (3) to form a rigid film, the puncture strength of the rigid film can be increased, for example, to 10 N or more. This allows the rigidity to be sufficient to prevent the bag from tearing even when a bag made of packaging material 10 containing the rigid film comes into contact with a sharp member having a pointed tip.

[0047] The stretched plastic films (1) to (3) will be described below. First, polyamide films will be described. Polyamide films contain 51% by mass or more of polyamide. The polyamide content in the polyamide film may be 80% by mass or more, 90% by mass or more, or 95% by mass or more. Examples of polyamides include aliphatic polyamides and aromatic polyamides. Aliphatic polyamides include nylons such as nylon-6, nylon-6,6, and copolymers of nylon 6 and nylon 6,6, and aromatic polyamides include polymetaxylene adipamide (MXD6).

[0048] The thickness of the polyamide film is preferably 12 μm or more, more preferably 15 μm or more, and is preferably 30 μm or less, more preferably 25 μm or less.

[0049] The polyamide film may be composed of a single layer or multiple layers. When the polyamide film includes multiple layers, it is, for example, a co-extruded film produced by co-extrusion. The polyamide film produced by co-extrusion includes, for example, a first layer made of a polyester such as PET, a second layer made of a polyamide such as nylon, and a third layer made of a polyester such as PET, laminated in this order. Note that when the mass of the second layer made of a polyamide such as nylon is 51% or more of the mass of the entire polyamide film, the polyamide film produced by co-extrusion can be said to be mainly composed of polyamide.

[0050] Next, the PBT film will be described. The PBT film contains 51% by mass or more of PBT. The PBT content in the PBT film may be 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or even 95% by mass or more. The PBT film may have either the first or second configuration described below.

[0051] The PBT film of the first configuration is produced by casting multiple layers of resins of the same composition, as disclosed in, for example, International Publication No. 2015 / 178390. In this case, the PBT film has a multilayer structure including at least 10 layers, preferably 60 layers or more, more preferably 250 layers or more, and even more preferably 1000 layers or more. Each of the multiple layers preferably contains 51% by mass or more of PBT, more preferably 60% by mass or more of PBT. In the multiple layers, the (n+1)th layer is directly laminated on the nth layer. That is, no adhesive or bonding layer is interposed between the multiple layers. The thickness of each layer is preferably 3 nm or more, more preferably 10 nm or more. The thickness of each layer is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 75 nm or less.

[0052] The overall thickness of the PBT film is preferably 9 μm or more, more preferably 12 μm or more. Furthermore, the overall thickness of the PBT film of the first configuration is preferably 25 μm or less, more preferably 20 μm or less. By making the PBT film thicker than 9 μm, the PBT film has sufficient strength. Furthermore, by making the PBT film thicker than 25 μm, the PBT film exhibits excellent formability. Therefore, the process of manufacturing a packaging bag by processing a packaging material 10 containing a PBT film can be carried out efficiently.

[0053] When the PBT film has a multilayer structure including multiple layers as described above, some of the multiple layers may contain a polyester resin other than PBT as a primary component. For example, a PBT film having a first configuration may be composed of multiple layers containing PBT as a primary component and a layer containing, for example, PET as a primary component located between two PBT layers. That is, the PBT film having the first configuration may be composed by alternately laminating layers containing PBT as a primary component and layers containing, for example, PET as a primary component.

[0054] Preferably, the tensile strength of the PBT film of the first configuration divided by the tensile elongation in at least one direction is 2.0 [MPa / %] or more. For example, the tensile strength of the PBT film divided by the tensile elongation in the transverse direction (TD) is preferably 2.0 [MPa / %] or more, more preferably 2.2 [MPa / %] or more. The tensile strength and tensile elongation can be measured in accordance with JIS K7127. A tensile tester STA-1150 manufactured by Orientec Co., Ltd. can be used as a measuring instrument. A rectangular film cut from PBT film with a width of 15 mm and a length of 150 mm can be used as a test piece. The distance between the pair of chucks holding the test piece at the start of measurement is 100 mm, and the tensile speed is 300 mm / min. The length of the test piece can be adjusted as long as the test piece can be held by the pair of chucks. In this application, unless otherwise specified, the environmental temperature during the test is 25°C and the relative humidity is 50%.

[0055] The PBT film of the second configuration is a monolayer film containing a polyester whose main repeating unit is butylene terephthalate, as disclosed in, for example, JP 2014-133332 A. For example, the PBT film contains a homo- or copolymer-type polyester obtained by condensing 1,4-butanediol or its ester-forming derivative as the glycol component and terephthalic acid or its ester-forming derivative as the dibasic acid component. The PBT content in the PBT film of the second configuration is preferably 51% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and most preferably 90% by mass or more. Furthermore, the PBT film of the second configuration is preferably composed only of polybutylene terephthalate and additives.

[0056] To impart mechanical strength to the PBT film of the second configuration, PBTs with a melting point of 200°C or higher and 250°C or lower and an IV value of 1.10 dL / g or higher and 1.35 dL / g or lower are preferred. Furthermore, PBTs with a melting point of 215°C or higher and 225°C or lower and an IV value of 1.15 dL / g or higher and 1.30 dL / g or lower are particularly preferred. These IV values ​​may be satisfied by the entire material constituting the PBT film. The IV value can be calculated based on JIS K 7367-5:2000.

[0057] The PBT film according to the second aspect may contain up to 30% by mass of a polyester resin other than PBT, such as PET. By including PET in the PBT film, PBT crystallization can be suppressed, improving the stretchability of the PBT film. The PET blended with the PBT in the PBT film may be a polyester whose main repeating unit is ethylene terephthalate. For example, a homotype primarily composed of ethylene glycol as the glycol component and terephthalic acid as the dibasic acid component is preferably used. To impart good mechanical strength properties, PETs with a melting point of 240°C to 265°C and an IV value of 0.55 dl / g to 0.90 dl / g are preferred. Furthermore, PETs with a melting point of 245°C to 260°C and an IV value of 0.60 dl / g to 0.80 dl / g are particularly preferred.

[0058] Next, the high stiffness film will be described. The high stiffness film contains polyester as a main component and has a loop stiffness of 0.0017 N or more in at least one direction.

[0059] Loop stiffness is a parameter that represents the stiffness of a film. A method for measuring loop stiffness will be described below with reference to FIGS. 6 to 11. The measurement method described below can be used not only for single-layer films such as stretched plastic films, but also for films containing multiple layers, such as vapor-deposited films and laminated films. A vapor-deposited film is a film that includes a single-layer film, such as a stretched plastic film, and a vapor-deposited layer formed on the single-layer film. A laminated film is a film that includes multiple laminated films, such as packaging material 10.

[0060] FIG. 6 is a plan view showing a test piece 60 and a loop stiffness measuring device 65, and FIG. 7 is a cross-sectional view of the test piece 60 and the loop stiffness measuring device 65 of FIG. 6 taken along line VV. The test piece 60 is a rectangular film having long and short sides. In the present application, the length L1 of the long side of the test piece 60 is 150 mm, and the length L2 of the short side is 15 mm. As the loop stiffness measuring device 65, for example, No. 581 Loop Stiffness Tester (registered trademark) LOOP STIFFNESS TESTER DA type manufactured by Toyo Seiki Seisakusho, Ltd. can be used. The length L1 of the long side of the test piece 60 is adjustable as long as the test piece 60 can be gripped by a pair of chucks 66, which will be described later.

[0061] The loop stiffness measuring device 65 has a pair of chuck portions 66 for gripping a pair of ends in the long side direction of the test specimen 60, and a support member 67 for supporting the chuck portions 66. The chuck portions 66 include a first chuck 661 and a second chuck 662. In the state shown in FIGS. 6 and 7, the test specimen 60 is placed on the pair of first chucks 661, and the second chuck 662 has not yet gripped the test specimen 60 between itself and the first chuck 661. As will be described later, during measurement, the test specimen 60 is gripped between the first chuck 661 and the second chuck 662 of the chuck portions 66. The second chuck 662 may be connected to the first chuck 661 via a hinge mechanism.

[0062] When a film to be measured, such as a stretched plastic film, a vapor-deposited film, or a laminated film, is available in a state before being processed into a packaging product, the test piece 60 may be prepared by cutting the film to be measured. Alternatively, the test piece 60 may be prepared by cutting a packaging product made from the packaging material 10, such as a packaging bag, and removing the film to be measured. For example, the test piece may be prepared by cutting the front film 74 or the back film 75 of the packaging bag 70, as shown by the dotted lines labeled 60A or 60B in FIGS. 12 and 13 (described below). When measuring the loop stiffness of the packaging material 10 in the machine direction, the test piece is prepared by cutting the front film 74 or the back film 75 of the packaging bag 70, as shown by the dotted lines labeled 60A or 60B in FIGS. 12 and 13 (described below), so that the long side of the test piece is aligned with the machine direction. When measuring the loop stiffness of the packaging material 10 in the vertical direction, a test specimen is prepared by cutting the front film 74 or the back film 75 of the packaging bag 70 so that the long side direction of the test specimen coincides with the vertical direction, as shown by the reference symbol 60B in Figures 12 and 13. Although not shown, the test specimen may also be prepared by cutting the bottom film 76 so that the long side direction of the test specimen coincides with the machine direction or the vertical direction.

[0063] A method for measuring the loop stiffness of a test piece 60 using a loop stiffness measuring device 65 will be described. First, as shown in FIGS. 6 and 7 , the test piece 60 is placed on a first chuck 661 of a pair of chucks 66 arranged with a gap L3 therebetween. In the present application, the gap L3 is set so that the length of a loop portion 61 (described later, also referred to as the loop length) is 60 mm. The test piece 60 includes an inner surface 60x located on the first chuck 661 side and an outer surface 60y located opposite the inner surface 60x. When the test piece 60 is made of a packaging material 10, the inner surface 60x and the outer surface 60y of the test piece 60 coincide with the inner surface and the outer surface of the packaging material 10. When a loop portion 61 (described later) is formed in the test piece 60, the inner surface 60x is located inside the loop portion 61, and the outer surface 60y is located outside the loop portion 61. Next, as shown in FIG. 8, the second chuck 662 is placed on the test piece 60 so that the end of the test piece 60 in the long side direction is gripped between the first chuck 661 and the second chuck 662.

[0064] Next, as shown in FIG. 9 , at least one of the pair of chuck portions 66 is slid on the support member 67 in a direction that reduces the distance between the pair of chuck portions 66. This allows a loop portion 61 to be formed on the test piece 60. The test piece 60 shown in FIG. 9 has a loop portion 61, a pair of intermediate portions 62, and a pair of fixing portions 63. The pair of fixing portions 63 are portions of the test piece 60 that are gripped by the pair of chuck portions 66. The pair of intermediate portions 62 are portions of the test piece 60 that are located between the loop portion 61 and the pair of intermediate portions 62. As shown in FIG. 9 , the chuck portion 66 is slid on the support member 67 until the inner surfaces 60x of the pair of intermediate portions 62 come into contact with each other. This allows a loop portion 61 having a loop length of 60 mm to be formed. The loop length of the loop portion 61 is the length of the test piece 60 between position P1 where the surface of one second chuck 662 on the loop portion 61 side intersects with the test piece 60, and position P2 where the surface of the other second chuck 662 on the loop portion 61 side intersects with the test piece 60. If the thickness of the test piece 60 is ignored, the above-mentioned distance L3 is the value obtained by adding 2×t to the length of the loop portion 61, where t is the thickness of the second chuck 662 of the chuck portion 66.

[0065] Then, as shown in FIG. 10 , the posture of the chuck portion 66 is adjusted so that the protruding direction Y of the loop portion 61 relative to the chuck portion 66 is horizontal. For example, the posture of the chuck portion 66 supported by the support member 67 is adjusted by moving the support member 67 so that the normal direction of the support member 67 is horizontal. In the example shown in FIG. 10 , the protruding direction Y of the loop portion 61 coincides with the thickness direction of the chuck portion. Furthermore, a load cell 68 is prepared at a position a distance Z1 away from the second chuck 662 in the protruding direction Y of the loop portion 61. In this application, the distance Z1 is set to 50 mm. Next, the load cell 68 is moved toward the loop portion 61 of the test piece 60 at a speed V by a distance Z2 shown in FIG. 10 . The distance Z2 is set so that the load cell 68 contacts the loop portion 61 and then pushes the loop portion 61 toward the chuck portion 66, as shown in FIGS. 10 and 11 . In this application, the distance Z2 is set to 40 mm. In this case, the distance Z3 between the load cell 68 and the second chuck 662 of the chuck portion 66 when the load cell 68 is pressing the loop portion 61 toward the chuck portion 66 is 10 mm. The speed V at which the load cell 68 is moved was set to 3.3 mm / sec.

[0066] Next, as shown in Figure 11, the load cell 68 is moved a distance Z2 toward the chuck portion 66, and in a state where the load cell 68 is pressing into the loop portion 61 of the test piece 60, the value of the load applied to the load cell 68 from the loop portion 61 becomes stable, and then the value of the load is recorded. The value of the load thus obtained is used as the loop stiffness of the film constituting the test piece 60. In this application, unless otherwise specified, the environment during measurement of loop stiffness is a temperature of 23°C and a relative humidity of 50%.

[0067] By using a high-stiffness film having a loop stiffness of 0.0017 N or more in at least one direction as the first stretched plastic film 11 or the second stretched plastic film 12, it is possible to increase the puncture strength of the first stretched plastic film 11 or the second stretched plastic film 12. This makes it possible to increase the puncture strength of a packaging material 10 including a high-stiffness film to, for example, 13 N or more, more preferably 14 N or more, and even more preferably 15 N or more or 16 N or more.

[0068] An example of a high-stiffness film is a high-stiffness PET film containing 51% by mass or more of PET. The PET content in the high-stiffness PET film may be 80% by mass or more, 90% by mass or more, or even 95% by mass or more. The thickness of the high-stiffness film is preferably 5 μm or more, more preferably 7 μm or more. The thickness of the high-stiffness film may be 10 μm or more, or may be 14 μm or more. The thickness of the high-stiffness film is preferably 30 μm or less, and may be 25 μm or less, or may be 20 μm or less.

[0069] The preferred mechanical properties of the high stiffness film will now be further described. The puncture strength of the high stiffness film is preferably 10 N or more, and more preferably 11 N or more. The tensile strength of the high stiffness film in at least one direction is preferably 250 MPa or more, more preferably 280 MPa or more. For example, the tensile strength of the high stiffness film in the machine direction is preferably 250 MPa or more, more preferably 280 MPa or more. The tensile strength of the high stiffness film in the perpendicular direction is preferably 250 MPa or more, more preferably 280 MPa or more. The tensile elongation of the high stiffness film in at least one direction is preferably 130% or less, more preferably 120% or less. For example, the tensile elongation of the high stiffness film in the machine direction is preferably 130% or less, more preferably 120% or less. The tensile elongation of the high stiffness film in the perpendicular direction is preferably 120% or less, more preferably 110% or less. Preferably, the tensile strength of the high stiffness film divided by the tensile elongation in at least one direction is 2.0 [MPa / %] or more. For example, the tensile strength of the high stiffness film divided by the tensile elongation in the transverse direction (TD) is preferably 2.0 [MPa / %] or more, more preferably 2.2 [MPa / %] or more. The tensile strength of the high stiffness film divided by the tensile elongation in the machine direction (MD) is preferably 1.8 [MPa / %] or more, more preferably 2.0 [MPa / %] or more.

[0070] The heat shrinkage of the high stiffness film in at least one direction is preferably 0.7% or less, more preferably 0.5% or less. For example, the heat shrinkage of the high stiffness film in the machine direction is preferably 0.7% or less, more preferably 0.5% or less. The heat shrinkage of the high stiffness film in the perpendicular direction is preferably 0.7% or less, more preferably 0.5% or less. The heating temperature for measuring the heat shrinkage is 100°C, and the heating time is 40 minutes. The Young's modulus of the high stiffness film in at least one direction is preferably 4.0 GPa or more, more preferably 4.5 GPa or more. For example, the Young's modulus of the high stiffness film in the machine direction is preferably 4.0 GPa or more, more preferably 4.5 GPa or more. The Young's modulus of the high stiffness film in the perpendicular direction is preferably 4.0 GPa or more, more preferably 4.5 GPa or more.

[0071] Like tensile strength and tensile elongation, Young's modulus can be measured in accordance with JIS K7127. A tensile tester STA-1150 manufactured by Orientec Co., Ltd. can be used as a measuring instrument. A rectangular film cut from a high-stiffness film with a width of 15 mm and a length of 150 mm can be used as a test piece. The distance between the pair of chucks holding the test piece at the start of measurement is 100 mm, and the tensile speed is 300 mm / min. The length of the test piece can be adjusted as long as the test piece can be held by the pair of chucks. Unless otherwise specified in this application, the environment during measurement of Young's modulus is a temperature of 25°C and a relative humidity of 50%. The Young's modulus of the packaging material 10 is measured in the same manner as for the high-stiffness polyester film, except that the measuring instrument is an Orientec RTC-1310A tensile tester, and the distance between the pair of chucks holding the test piece is 50 mm at the start of the measurement. When measuring the Young's modulus of the packaging material 10, a test piece can be prepared by cutting the front film 74, back film 75, or bottom film 76 of the packaging bag 70 so that the long side direction of the test piece coincides with the flow direction or the vertical direction, as in the case of measuring the loop stiffness.

[0072] In the packaging material 10 including a high-stiffness film, the high-stiffness film may be provided with a metal vapor-deposited layer 22 as described above. In this case, the high-stiffness film provided with the metal vapor-deposited layer 22 may have mechanical properties equivalent to those of a single high-stiffness film. For example, the high-stiffness film provided with the metal vapor-deposited layer 22 may have a loop stiffness of 0.0017 N or more in at least one direction.

[0073] In the manufacturing process of a high-stiffness film, for example, a plastic film obtained by melting and molding polyester is first stretched 3 to 4.5 times in both the machine direction and the perpendicular direction at 90 to 145°C in a first stretching step. This is followed by a second stretching step in which the plastic film is stretched 1.1 to 3.0 times in both the machine direction and the perpendicular direction at 100 to 145°C in a second stretching step. This is followed by heat setting at 190 to 220°C. This is followed by a relaxation treatment (treatment to reduce the film width) of approximately 0.2 to 2.5% in both the machine direction and the perpendicular direction at 100 to 190°C. By adjusting the stretch ratio, stretching temperature, heat setting temperature, and relaxation treatment rate in these steps, a high-stiffness film having the above-mentioned mechanical properties can be obtained.

[0074] When packaging material 10 includes a rigid film such as a high-stiffness film, strength such as puncture resistance can be imparted to packaging material 10 and packaged products such as packaging bag 70 made from packaging material 10. This can prevent packaging bag 70 from being torn when a sharp member with a pointed tip comes into contact with packaging bag 70. The puncture strength of packaging material 10 including a rigid film is, for example, 13.0 N or more, or alternatively, 14.0 N or more, 15.0 N or more, or 16.0 N or more.

[0075] Furthermore, when packaging material 10 includes a rigid film such as a high-stiffness film, the Young's modulus of packaging material 10 can be increased. The Young's modulus of packaging material 10 in one direction is, for example, 3200 MPa or more, or may be 3300 MPa or more, 3400 MPa or more, 3500 MPa or more, 3600 MPa or more, or 3700 MPa or more. The Young's modulus of packaging material 10 in a direction perpendicular to the above-mentioned one direction is, for example, 2700 MPa or more, 2800 MPa or more, 2900 MPa or more, 3000 MPa or more, 3100 MPa or more, or 3200 MPa or more. For example, the Young's modulus of packaging material 10 in the machine direction (MD) may be, for example, 3200 MPa or more, 3300 MPa or more, 3400 MPa or more, 3500 MPa or more, 3600 MPa or more, or 3700 MPa or more. When the packaging material 10 comprises a PBT film or a high-stiffness film, the Young's modulus of the packaging material 10 in the machine direction (MD) can be 3500 MPa or more. Furthermore, the Young's modulus of the packaging material 10 in the transverse direction (TD), which is the direction perpendicular to the machine direction (MD), is, for example, 2700 MPa or more, or may be 2800 MPa or more, 2900 MPa or more, 3000 MPa or more, 3100 MPa or more, or 3200 MPa or more. A high Young's modulus of the packaging material 10 makes the packaging material 10 less likely to stretch. This increases the processing accuracy when processing the packaging material 10 in the manufacturing process of a packaged product such as a packaging bag 70. Furthermore, when the packaging material 10 is used to produce a gusseted packaging bag 70 configured to be self-supporting, as described below, the self-supporting ability of the packaging bag 70 is improved.

[0076] (Virgin Films) Virgin films are films made from non-recycled resins. Examples of virgin films include the above-mentioned fossil fuel PET and biomass PET. When a virgin film contains PET, such as fossil fuel PET or biomass PET, as a primary component, the PET content in the virgin film may be 80% by mass or more, 90% by mass or more, or even 95% by mass or more. The puncture strength of the virgin film is lower than that of the above-mentioned rigid film, for example, less than 10 N. The loop stiffness of the virgin film is lower than that of the above-mentioned high-stiffness film, for example, less than 0.0017 N in both the machine direction (MD) and the transverse direction (TD). The thickness of the virgin film varies depending on its application, but is typically between 5 μm and 100 μm, preferably between 5 μm and 25 μm.

[0077] (OPP film) The OPP film contains polypropylene derived from fossil fuels. The puncture strength of the OPP film is lower than that of the aforementioned rigid film, for example, less than 10 N. The polypropylene content of the OPP film may be 80% by mass or more, 90% by mass or more, or even 95% by mass or more. The loop stiffness of the OPP film is lower than that of the aforementioned high-stiffness film, for example, less than 0.0017 N in both the machine direction (MD) and the transverse direction (TD). The thickness of the OPP film varies depending on its intended use, but is typically between about 5 μm and 100 μm, and preferably between 18 μm and 40 μm.

[0078] [Metal deposition layer] Next, the metal vapor deposition layer 22 will be described. The metal vapor deposition layer 22 is a layer made of a metal vapor deposition film that can be formed by a conventionally known vapor deposition method. By providing the metal vapor deposition layer 22, it is possible to impart a metallic luster to the packaging bag, thereby improving the design. It is also possible to impart or improve light blocking properties that prevent the transmission of visible light, ultraviolet light, and the like. It can also contribute to gas barrier properties that prevent the transmission of oxygen gas, water vapor, and the like.

[0079] For example, one or more metal materials selected from the group consisting of aluminum (Al), magnesium (Mg), tin (Sn), sodium (Na), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), gold (Au), and chromium (Cr) can be used as the material for forming the metal vapor deposition layer 22. In particular, for packaging bags, it is preferable that the metal vapor deposition layer 22 comprises an aluminum vapor deposition layer.

[0080] The metal vapor deposition layer 22 may be composed of a single layer or multiple layers. Each of the single layer and multiple layers contains one or more metal materials selected from the group described above. When the metal vapor deposition layer 22 includes multiple layers, each layer may contain the same metal material or different metal materials.

[0081] The thickness of the metal vapor deposition layer 22 varies depending on the type of metal used, but is selected arbitrarily within the range of, for example, 50 Å to 2000 Å, preferably 100 Å to 1000 Å. More specifically, in the case of an aluminum vapor deposition layer, the thickness is preferably 300 Å to 1000 Å, more preferably 350 Å to 900 Å.

[0082] Methods for forming the metal vapor deposition layer 22 include, for example, physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, or chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0083] The surface of the second stretched plastic film 12 on which the metal vapor deposition layer 22 is provided may be treated or have a layer formed thereon to improve adhesion of the metal vapor deposition layer 22 to the second stretched plastic film 12. For example, the surface of the second stretched plastic film 12 may be subjected to a plasma treatment using plasma.

[0084] [Sealant layer] The sealant layer 15 is disposed on the content side of the packaging bag when the packaging material 10 is used to produce a packaging bag, and functions to seal the packaging materials 10 together. The sealant layer is a layer formed from a thermoplastic resin that can be fused to each other by heat. The sealant layer 15 may contain a resin material derived from fossil fuels or a resin material derived from biomass.

[0085] The resin material forming the sealant layer 15 is not particularly limited as long as it is a resin that can be fused to each other by heat, and specific examples thereof include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene and polypropylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMA), and the like. A), ethylene-methyl methacrylate copolymer (EMMA), ionomer resin, heat-sealable ethylene-vinyl alcohol resin, or polyolefin resins such as methylpentene resin, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, polyethylene, polypropylene or cyclic olefin copolymer, acid-modified polyolefin resins obtained by modifying polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, polyvinyl acetate resin, poly(meth)acrylic resin, polyvinyl chloride resin, and others. These may be used alone or in combination of two or more.

[0086] The sealant layer 15 may be formed by laminating a film or sheet of the above-mentioned resin onto the second stretched plastic film 12 via the second adhesive layer 17. The sealant layer 15 of the packaging material 10 shown in Figures 1 and 2 above is an example of a sealant layer formed by laminating a film or sheet onto the second stretched plastic film 12 via the second adhesive layer 17. The sealant layer 15 may also be formed by extruding the above-mentioned resin onto the second stretched plastic film 12. The sealant layer 15 of the packaging material 10 shown in Figures 3 and 4 above is an example of a sealant layer formed on the second stretched plastic film 12 by extrusion molding. When the sealant layer 15 is formed by extrusion molding, a second anchor coat layer 19 may be provided on the inner surface of the second stretched plastic film 12, as shown in Figures 3 and 4.

[0087] When polyethylene is used as the resin material forming the sealant layer 15, in addition to ethylene obtained from fossil fuels, polymerized ethylene derived from biomass may also be used as the raw material. Specific examples of biomass-derived ethylene that can be used include those described in JP 2012-251006 A. By using polyethylene obtained by polymerizing biomass-derived ethylene as the material constituting the sealant layer 15, a layer made of a carbon-neutral material can be formed, further reducing the amount of fossil fuel used and the environmental impact.

[0088] As the biomass-derived ethylene, commercially available products may be used, such as "C4LL-LL118 (d=0.916, MFR=1.0 g / 10 min)" sugarcane-derived linear low-density polyethylene resin and "SBC118 (d=0.918, MFR=8.1 g / 10 min)" sugarcane-derived low-density polyethylene resin, both manufactured by Braskem.

[0089] In this embodiment, the sealant layer 15 is a single layer, but the sealant layer 15 may have two or more layers. When the sealant layer 15 has two or more layers, each layer may have the same composition or different compositions. For example, the sealant layer 15 may be configured as three layers, with a first layer, a second layer, and a third layer laminated in this order, and the first and third layers may be made of a resin material derived from fossil fuels, and the second layer may be made of a resin material containing a biomass-derived resin material. When the sealant layer 15 is configured as two or more layers, they may be laminated using a co-extrusion method.

[0090] The thickness of the sealant layer 15 is preferably 10 μm or more and 150 μm or less, and more preferably 18 μm or more and 120 μm or less.

[0091] [Adhesive layer] The first adhesive layer 16 is a layer that bonds a film including the first stretched plastic film 11 to a film including the second stretched plastic film 12. The second adhesive layer 17 is a layer that bonds a film including the second stretched plastic film 12 to a film including the sealant layer 15. When the sealant layer 15 is formed on the second stretched plastic film 12 by extrusion molding, the packaging material 10 does not need to include the second adhesive layer 17, as shown in Figures 3 and 4.

[0092] The adhesive layers such as the first adhesive layer 16 and the second adhesive layer 17 may be adhesive layers or adhesive resin layers. The adhesive layers and adhesive resin layers will be described below.

[0093] The adhesive layer can be formed by a conventional method, such as a dry lamination method. When two layers are bonded by the dry lamination method, the adhesive layer is formed by applying an adhesive to the surface of the layer to be laminated and drying it. Examples of adhesives that can be applied include one-component or two-component curing or non-curing vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, and other solvent-based, water-based, or emulsion-based adhesives. Two-component curing adhesives can include cured products of polyols and isocyanate compounds. Examples of coating methods for the laminating adhesive include direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fountain coating, transfer roll coating, and other methods. The adhesive layer after drying has a thickness of, for example, 1 μm to 10 μm, preferably 2 μm to 5 μm.

[0094] The adhesive layer may contain a biomass-derived component. For example, when the adhesive layer contains a cured product of a polyol and an isocyanate compound, at least one of the polyol and the isocyanate compound may contain a biomass-derived component. This can further improve the biomass content of the packaging material 10.

[0095] The adhesive resin layer contains a thermoplastic resin. The adhesive resin layer can be formed by a conventionally known method, such as a melt extrusion lamination method or a sand lamination method. Examples of the thermoplastic resin that can be used for the adhesive resin layer include polyethylene resins, polypropylene resins, cyclic polyolefin resins, copolymer resins, modified resins, and mixtures (including alloys) containing these resins as the main components. Examples of polyolefin resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), ethylene-α-olefin copolymers polymerized using metallocene catalysts, random or block copolymers of ethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, and ionomer resins. To improve interlayer adhesion, acid-modified polyolefin resins can be used, which are modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid. Furthermore, resins obtained by graft polymerization or copolymerization of unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers onto polyolefin resins can also be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more. The adhesive resin layer has a thickness of, for example, 5 μm to 50 μm, preferably 10 μm to 30 μm.

[0096] The polyethylene resin may be one that uses biomass-derived ethylene as a monomer unit, as described for the sealant layer 15. This can further improve the biomass content of the packaging material 10.

[0097] [Anchor coat layer] Anchor coat layers such as the first anchor coat layer 18 and the second anchor coat layer 19 are layers formed by applying an anchor coating agent onto a predetermined layer or film and drying it. The anchor coat layer can improve adhesion between the predetermined layer or film on which the anchor coat layer is provided and a layer formed by extrusion onto the predetermined layer or film. The anchor coat layer after drying has a thickness of, for example, 0.1 μm or more and 1 μm or less, preferably 0.3 μm or more and 0.5 μm or less.

[0098] 2 and 4, when the first adhesive layer 16 is an adhesive resin layer, a first anchor coat layer 18 can be provided on the first stretched plastic film 11 or on a printed layer 21 provided on the first stretched plastic film 11. This can improve the adhesion of the first adhesive layer 16 to the first stretched plastic film 11 or the printed layer 21. Furthermore, when the second adhesive layer 17 is an adhesive resin layer, a second anchor coat layer 19 can be provided on the second stretched plastic film 12, as shown in Figure 2. This can improve the adhesion of the second adhesive layer 17 to the second stretched plastic film 12. Furthermore, when the sealant layer 15 is formed by extrusion molding, a second anchor coat layer 19 can be provided on the second stretched plastic film 12, as shown in Figures 3 and 4. This can improve the adhesion of the sealant layer 15 to the second stretched plastic film 12.

[0099] Examples of anchor coating agents include anchor coating agents made of any resin with a heat resistance temperature of 135°C or higher, such as vinyl-modified resin, epoxy resin, urethane resin, polyester resin, polyethyleneimine, etc., but anchor coating agents that are cured products of polyacrylic or polymethacrylic resins (polyols) having two or more hydroxyl groups in the structure and an isocyanate compound as a curing agent are particularly preferred. A silane coupling agent may also be used in combination with this as an additive, and soluble nitrocellulose may also be used in combination to improve heat resistance.

[0100] The anchor coat layer may contain a biomass-derived component. For example, when the anchor coat layer contains a cured product of a polyol and an isocyanate compound, at least one of the polyol and the isocyanate compound may contain a biomass-derived component. This can further improve the biomass content of the packaging material 10.

[0101] [Print layer] The printing layer 21 is a layer on which any desired printed pattern such as letters, numbers, pictures, figures, symbols, designs, etc. is formed for the purpose of decoration, indication of contents, indication of expiration date, indication of manufacturer, seller, etc., or for the purpose of adding aesthetic appeal. The printing layer 21 can be provided as needed, and can be provided, for example, between the first stretched plastic film 11 and the first adhesive layer 16. The printing layer 21 may be provided on the entire surface of the first stretched plastic film 11, or on only a part of it. The printing layer 21 can be formed using conventionally known pigments or dyes, and the method of forming it is not particularly limited.

[0102] The printing layer preferably has a thickness of 0.1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less, and even more preferably 1 μm or more and 3 μm or less.

[0103] The printed layer 21 may contain a biomass-derived component. For example, when the printed layer 21 contains a cured product of a polyol and an isocyanate compound, at least one of the polyol and the isocyanate compound may contain the biomass-derived component.

[0104] In this embodiment, as described above, packaging material 10 includes a recycled film containing recycled PET in a proportion of, for example, 50% by weight to 95% by weight. This makes it possible to provide packaging material 10 that is more effective at reducing CO2 emissions than packaging materials that do not include recycled PET. Furthermore, by providing packaging material 10 with metal vapor deposition layer 22, it is possible to impart design features to packaging material 10.

[0105] <Manufacturing method of packaging materials> Next, an example of a method for manufacturing the packaging material 10 will be described. First, an example of a method for manufacturing the packaging material 10 shown in FIG.

[0106] (Manufacturing method of the packaging material in Figure 1) First, the above-described first stretched plastic film 11 and second stretched plastic film 12 are prepared. A printed layer 21 may be provided in advance on the first stretched plastic film 11. Furthermore, a metal vapor deposition layer 22 may be provided in advance on the second stretched plastic film 12.

[0107] Next, the first stretched plastic film 11 and the second stretched plastic film 12 are laminated together by dry lamination via a first adhesive layer 16 made of an adhesive layer. After that, the laminate including the first stretched plastic film 11 and the second stretched plastic film 12 is laminated together with the film constituting the sealant layer 15 via a second adhesive layer 17 made of an adhesive layer by dry lamination. In this way, a packaging material 10 including the first stretched plastic film 11, the second stretched plastic film 12, and the sealant layer 15 can be obtained.

[0108] Alternatively, the packaging material 10 may be produced by first laminating the second stretched plastic film 12 and the film constituting the sealant layer 15 by a dry lamination method via a second adhesive layer 17 consisting of an adhesive layer, and then laminating the first stretched plastic film 11 and a laminate including the second stretched plastic film 12 and the sealant layer 15 by a dry lamination method via a first adhesive layer 16 consisting of an adhesive layer.

[0109] In the dry lamination method, an adhesive composition is first applied to one of the two films to be laminated. The applied adhesive composition is then dried to volatilize the solvent. The two films are then laminated together via the dried adhesive composition. The two laminated films are then rolled up and aged, for example, at 20°C or higher for 24 hours or more.

[0110] The packaging material 10 can also be subjected to secondary processing to impart surface functions such as chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubrication functions, optical functions, thermal functions, and biocompatibility. Examples of secondary processing include embossing, painting, adhesives, printing, metallizing (plating, etc.), machining, and surface treatments (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.). The packaging material 10 can also be subjected to lamination (dry lamination or extrusion lamination), bag making, and other post-processing to produce molded products.

[0111] (Manufacturing method of packaging material in Figure 2) Next, an example of a method for manufacturing the packaging material 10 of FIG. 2 will be described.

[0112] First, a first anchor coat layer 18 is provided on the printing layer 21 provided on the first stretched plastic film 11. Next, the first stretched plastic film 11 and the second stretched plastic film 12 are laminated together by sand lamination, with a first adhesive layer 16 made of an adhesive resin layer interposed therebetween. Next, a second anchor coat layer 19 is provided on the inner surface of the second stretched plastic film 12. After that, a laminate including the first stretched plastic film 11 and the second stretched plastic film 12 is laminated to the film constituting the sealant layer 15 by sand lamination, with a second adhesive layer 17 made of an adhesive resin layer interposed therebetween. This allows for the production of a packaging material 10 comprising the first stretched plastic film 11, the second stretched plastic film 12, and the sealant layer 15.

[0113] Alternatively, the packaging material 10 may be produced by first laminating the second stretched plastic film 12 and the film constituting the sealant layer 15 by sandwich lamination via a second adhesive layer 17 consisting of an adhesive resin layer, and then sandwiching the first stretched plastic film 11 and a laminate including the second stretched plastic film 12 and the sealant layer 15 by sandwich lamination via a first adhesive layer 16 consisting of an adhesive resin layer.

[0114] In the sand lamination method, a molten resin that forms an adhesive resin layer is first extruded onto one of the two films to be laminated, and then the other film is laminated onto the resin extruded onto the one film.

[0115] (Manufacturing method of packaging material in Figure 3) Next, an example of a method for manufacturing the packaging material 10 of FIG. 3 will be described.

[0116] First, as in the manufacturing method of the packaging material 10 of Fig. 1, a first stretched plastic film 11 and a second stretched plastic film 12 are laminated together by dry lamination via a first adhesive layer 16 made of an adhesive layer. Next, a second anchor coat layer 19 is provided on the inner surface of the second stretched plastic film 12. Thereafter, a sealant layer 15 is formed on the second anchor coat layer 19 provided on the second stretched plastic film 12 by melt extrusion lamination. In this way, a packaging material 10 comprising the first stretched plastic film 11, the second stretched plastic film 12, and the sealant layer 15 can be obtained.

[0117] (Manufacturing method of packaging material in Figure 4) Next, an example of a manufacturing method for the packaging material 10 of Fig. 4 will be described. First, as in the manufacturing method for the packaging material 10 of Fig. 2, a first stretched plastic film 11 and a second stretched plastic film 12 are laminated together by sand lamination via a first adhesive layer 16 made of an adhesive resin layer. Next, a second anchor coat layer 19 is provided on the inner surface of the second stretched plastic film 12. Thereafter, a sealant layer 15 is formed on the second anchor coat layer 19 provided on the second stretched plastic film 12 by melt extrusion lamination. This allows for the production of a packaging material 10 comprising the first stretched plastic film 11, the second stretched plastic film 12, and the sealant layer 15.

[0118] <Packaging bag> The packaging material 10 is used as a material for forming a packaging bag. For example, packaging bags of various shapes can be produced by folding the packaging material 10, or by preparing two sheets of the packaging material 10 and overlapping them with the sealant layer 15 of the front packaging material 10 facing the sealant layer 15 of the back packaging material 10, and then heat-sealing the peripheral edges using a heat seal method such as a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a flared seal type (pillow seal type), a flat bottom seal type, or a square bottom seal type. Also, a gusset-type packaging bag can be produced by inserting the folded packaging material 10 between the front packaging material 10 and the back packaging material 10 and heat-sealing the inserted material. It is not necessary for all of the packaging materials constituting the packaging bag to be the packaging material 10 of the present invention. In other words, it is sufficient that at least a portion of the packaging material that makes up the packaging bag is packaging material 10 that includes a recycled film and a rigid film, and the other portion of the packaging material that makes up the packaging bag may be packaging material that does not include a recycled film or a rigid film.

[0119] Heat sealing can be performed by any known method, such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, or ultrasonic sealing.

[0120] Packaging bags formed using the packaging material 10 can be suitably used to package various types of food and beverages, such as food and beverages, fruit juice, juice, drinking water, alcohol, cooked foods, fish paste products, frozen foods, meat products, simmered dishes, rice cakes, liquid soups such as hot pot soup, seasonings, etc., cosmetics such as liquid detergent, shampoo, rinse, and conditioner, hygiene products, daily necessities, and chemical products.

[0121] Fig. 12 is a diagram showing an example of a packaging bag 70 including packaging material 10. The packaging bag 70 includes a surface film 74 that forms the surface, a back film 75 that forms the back surface, and a lower film 76 that forms the lower portion 72. The lower film 76 is folded back at a fold-back portion 76f and is disposed between the surface film 74 and the back film 75. In this way, the packaging bag 70 shown in Fig. 12 is a self-standing pouch whose lower portion is configured as a gusset portion.

[0122] The inner surfaces of the front film 74, back film 75, and bottom film 76 are joined together by a seal portion. In front views of the packaging bag 70, such as FIG. 12, the seal portion is hatched. As shown in FIG. 12, the seal portion has an outer edge seal portion that extends along the outer edge of the packaging bag 70. The outer edge seal portion includes a bottom seal portion 72a that extends to the bottom 72, and a pair of side seal portions 73a that extend along a pair of side portions 73. Note that, in the packaging bag 70 before it is filled with contents (a state in which no contents are filled), as shown in FIG. 12, the top 71 of the packaging bag 70 forms an opening 71b. After the contents are placed in the packaging bag 70, the inner surfaces of the front film 74 and the back film 75 are joined at the top 71 to form an upper seal portion, thereby sealing the packaging bag 70.

[0123] The terms "surface film," "back film," and "bottom film" mentioned above merely distinguish each film according to its positional relationship, and the terms do not limit the method of providing packaging material 10 when manufacturing packaging bag 70. For example, packaging bag 70 may be manufactured using one sheet of packaging material 10 in which surface film 74, back film 75, and bottom film 76 are continuously arranged, or may be manufactured using two sheets of packaging material 10, one sheet of packaging material 10 in which surface film 74 and bottom film 76 are continuously arranged and one sheet of back film 75, or may be manufactured using three sheets of packaging material 10, one sheet of surface film 74, one sheet of back film 75, and one sheet of bottom film 76.

[0124] As shown in Fig. 12, the packaging bag 70 may include a spout 85. The spout 85 is a portion through which the contents stored in the storage portion 79 pass when the contents are removed. In this case, the contents are a liquid having fluidity. The width of the spout 85 is narrower than the width of the storage portion 79. This allows the user to accurately determine the pouring direction of the contents to be poured from the packaging bag 70 through the spout 85.

[0125] 12, the spout section 85 is made up of a portion of the front film 74 and the back film 75. For example, the spout section 85 includes a spout seal section 86 that joins the front film 74 and the back film 75 together to define the spout section 85 having a width narrower than that of the storage section 79. The packaging bag 70 having such a spout section 85 is suitable for use as a refill pouch that contains contents such as detergent, shampoo, and conditioner that can be refilled into a bottle.

[0126] At least one of the front film 74, the back film 75, and the bottom film 76 is made of a packaging material 10 including a recycled film and a metal vapor deposition layer 22. By using a packaging material 10 including a recycled film and a metal vapor deposition layer 22, it is possible to reduce the amount of fossil fuel used compared to conventional methods, thereby reducing the environmental impact. It is also possible to impart design features to the packaging bag 70. Furthermore, when the packaging material 10 includes a rigid film, it is possible to prevent the packaging bag 70 from being torn even when a sharp object with a pointed tip comes into contact with the packaging bag 70.

[0127] As long as the contents can be appropriately poured, the configuration of the pouring outlet part 85 is not limited to the configuration shown in Fig. 12. For example, the pouring outlet part 85 may be a member, such as a spout, separate from the front film 74 and the back film 75.

[0128] Fig. 13 is a diagram showing another example of a packaging bag 70 including packaging material 10. The packaging bag 70 shown in Fig. 13 is a pillow pouch formed by joining the inner surfaces of a film 77 folded into a cylindrical shape at an upper portion 71, a lower portion 72, and a seam portion 78. The upper portion 71 and the lower portion 72 include an upper sealed portion 71a and a lower sealed portion 72a. The seam portion 78 also includes a seam sealed portion 78a that extends from the upper sealed portion 71a to the lower sealed portion 72a.

[0129] The packaging bag 70 shown in Figure 13 is suitable for use as a pouch or zipper bag for storing snacks, gummies, chocolates, and other confectioneries, regular coffee bags, and small amounts of liquids such as miso, noodle soup, and sauces (100 ml or less).

[0130] In the packaging bag 70 shown in FIG. 13, the film 77 is also made of packaging material 10 including a recycled film and a metal vapor deposition layer 22. This allows for a reduction in the amount of fossil fuel used compared to conventional methods, thereby reducing the environmental impact. It also allows for a design to be added to the packaging bag 70. Furthermore, when the packaging material 10 includes a rigid film, it is possible to prevent the packaging bag 70 from being torn even when a sharp member with a pointed tip comes into contact with the packaging bag 70.

[0131] Although not shown, the packaging bag 70 may be a three-sided sealed pouch or a four-sided sealed pouch formed by joining the front film 74 and the back film 75 on three or four sides along the outer edge.

[0132] In the above-described embodiment, an example has been shown in which the laminate of the present embodiment is used as a packaging material 10 for forming a bag. However, the laminate of the present embodiment may be used for purposes other than packaging. For example, the laminate of the present embodiment may be used as a label that is attached to an object by thermal welding. [Example]

[0133] Next, the present invention will be explained in more detail with reference to examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0134] [Example 1] A biaxially stretched recycled PET film containing PET recycled by mechanical recycling was prepared as the first stretched plastic film 11. The recycled PET film contained 90% or more by mass of PET. The recycled PET film had a thickness of 12 μm. A printed layer 21 was also formed on the recycled PET film.

[0135] A biaxially stretched recycled PET film containing mechanically recycled PET was prepared as the second stretched plastic film 12. The recycled PET film contained 90% or more by mass of PET. The thickness of the recycled PET film can be selected within a range of 9 μm to 25 μm, but was set to 12 μm in this example. In addition, a metal vapor deposition layer 22 made of aluminum and having a thickness of 450 Å was formed on the recycled PET film.

[0136] Next, the adhesive was applied onto the printed layer 21 provided on the recycled PET film of the first stretched plastic film 11 and dried to obtain a first adhesive layer 16. Next, the recycled PET film of the first stretched plastic film 11 and the recycled PET film of the second stretched plastic film 12 were bonded together via the first adhesive layer 16. At this time, the bonding was performed so that the metal vapor deposition layer 22 provided on the recycled PET film of the second stretched plastic film 12 faced the recycled PET film side of the first stretched plastic film 11.

[0137] A polyethylene film containing linear low-density polyethylene was prepared as the sealant layer 15. The thickness of the polyethylene film can be selected within the range of 20 μm to 100 μm, but was set to 30 μm here.

[0138] Next, the laminate including the recycled PET film of the first stretched plastic film 11 and the recycled PET film of the second stretched plastic film 12 was bonded to a polyethylene film by dry lamination via a second adhesive layer 17 made of an adhesive. In this way, a packaging material 10 was produced.

[0139] The layer structure of the packaging material 10 of this embodiment is expressed as follows. Recycled PET12 / Stamp / Adhesive / Vapor Deposition / Recycled PET12 / Adhesive / PE(1)30 "Recycled PET" refers to recycled PET film. "Mark" refers to the printed layer. "Adhesive" refers to the adhesive layer. "Vapor deposition" refers to the metal vapor deposition layer. "PE(1)" refers to polyethylene film. The numbers refer to the layer thickness (unit: μm).

[0140] The packaging material 10 produced as described above was folded into a cylindrical shape, and the inner surfaces of the folded packaging material 10 were joined together at the upper portion 71, the lower portion 72, and the seam portion 78 to produce the packaging bag 70 shown in Fig. 13. The packaging bag 70 of this example can suitably store regular coffee.

[0141] [Example 2] A biaxially stretched polypropylene film containing polypropylene was prepared as the first stretched plastic film 11. The stretched polypropylene film contained 90% or more by mass of polypropylene. The thickness of the stretched polypropylene film can be selected within the range of 20 μm to 40 μm, but was set to 20 μm here. In addition, a printed layer 21 was formed on the stretched polypropylene film.

[0142] A biaxially stretched recycled PET film containing mechanically recycled PET was prepared as the second stretched plastic film 12. The recycled PET film contained 90% or more by mass of PET. The recycled PET film had a thickness of 12 μm. A metal vapor deposition layer 22 made of aluminum and having a thickness of 450 Å was formed on the recycled PET film.

[0143] Next, in the same manner as in Example 1, the stretched polypropylene film and the recycled PET film were bonded together by dry lamination via the first adhesive layer 16 made of an adhesive.

[0144] A polyethylene film containing linear low-density polyethylene was prepared as the sealant layer 15. The thickness of the polyethylene film can be selected within the range of 20 μm to 80 μm, but was set to 30 μm here.

[0145] Next, in the same manner as in Example 1, the laminate including the stretched polypropylene film and the recycled PET film was bonded to the polyethylene film by dry lamination via the second adhesive layer 17 made of an adhesive. In this manner, the packaging material 10 was produced.

[0146] The layer structure of the packaging material 10 of this embodiment is expressed as follows. OPP20 / Printing / Adhesive / Vapor deposition / Recycled PET12 / Adhesive / PE(1)30 "OPP" stands for oriented polypropylene film.

[0147] Next, the packaging material 10 produced as described above was used to produce a packaging bag 70 shown in Fig. 13 in the same manner as in Example 1. The packaging bag 70 of this example can suitably store regular coffee.

[0148] [Example 3] A biaxially stretched polypropylene film containing polypropylene was prepared as the first stretched plastic film 11. The stretched polypropylene film contained 90% or more by mass of polypropylene. The thickness of the stretched polypropylene film can be selected within the range of 18 μm to 40 μm, but was set to 20 μm here. In addition, a printed layer 21 was formed on the stretched polypropylene film.

[0149] A biaxially stretched recycled PET film containing mechanically recycled PET was prepared as the second stretched plastic film 12. The recycled PET film contained 90% or more by mass of PET. The recycled PET film had a thickness of 12 μm. A metal vapor deposition layer 22 made of aluminum and having a thickness of 450 Å was formed on the recycled PET film.

[0150] Next, a first anchor coat layer 18 was formed on the printed layer 21 on the stretched polypropylene film, and then the stretched polypropylene film and the recycled PET film were bonded together by sand lamination via a first adhesive layer 16 made of an adhesive resin. Low-density polyethylene was used as the adhesive resin. The thickness of the first adhesive layer 16 was 10 μm.

[0151] An unstretched polypropylene film was prepared as the sealant layer 15. The thickness of the unstretched polypropylene film can be selected within the range of 10 μm or more and 50 μm or less, but was set to 18 μm here.

[0152] Next, a second anchor coat layer 19 was formed on the recycled PET film, and then the laminate including the stretched polypropylene film and the recycled PET film was bonded to a polyethylene film by sandwich lamination via a second adhesive layer 17 made of an adhesive resin. Low-density polyethylene was used as the adhesive resin. The thickness of the second adhesive layer 17 was 10 μm. In this way, a packaging material 10 was produced.

[0153] The layer structure of the packaging material 10 of this embodiment is expressed as follows. OPP20 / Stamp / AC / Adhesive Resin / Vapor Deposition / Recycled PET12 / AC / Adhesive Resin / PP(1)18 "AC" represents an anchor coat layer. "Adhesive resin" represents an adhesive resin layer. "PP(1)" means a polypropylene film.

[0154] Next, the packaging material 10 produced as described above was used to produce a packaging bag 70 shown in Fig. 13 in the same manner as in Example 1. The packaging bag 70 of this example can suitably contain snack foods.

[0155] [Example 4] A packaging material 10 was produced in the same manner as in Example 3, except that a biaxially stretched recycled PET film was used as the first stretched plastic film 11 instead of the stretched polypropylene film, and a polyethylene film containing linear low-density polyethylene was used as the sealant layer 15. The recycled PET film contained 90% or more by mass of PET. The thickness of the recycled PET film of the first stretched plastic film 11 was 12 μm. The thickness of the polyethylene film can be selected within the range of 10 μm to 50 μm, but was set to 30 μm here.

[0156] The layer structure of the packaging material 10 of this embodiment is expressed as follows. Recycled PET12 / Stamp / AC / Adhesive Resin / Vapor Deposition / Recycled PET12 / AC / Adhesive Resin / PE(1)30

[0157] Next, the packaging material 10 produced as described above was used to produce a packaging bag 70 shown in Fig. 13 in the same manner as in Example 1. The packaging bag 70 of this example can suitably store regular coffee.

[0158] [Example 5] A laminate including a stretched polypropylene film as the first stretched plastic film 11 and a recycled PET film as the second stretched plastic film 12 was produced in the same manner as in Example 3. Subsequently, a second anchor coat layer 19 was formed on the recycled PET film, and then molten low-density polyethylene was extruded onto the second anchor coat layer 19 to form a sealant layer 15 having a thickness of 30 μm. In this manner, a packaging material 10 was produced.

[0159] The layer structure of the packaging material 10 of this embodiment is expressed as follows. OPP20 / Stamp / AC / Adhesive resin / Vapor deposition / Recycled PET12 / AC / PE(2)30 "PE(2)" represents a layer of polyethylene formed by melt extrusion lamination.

[0160] Next, the packaging material 10 produced as described above was used to produce a packaging bag 70 shown in Fig. 13 in the same manner as in Example 1. The packaging bag 70 of this example can suitably store regular coffee.

[0161] [Example 6] A packaging material 10 was produced in the same manner as in Example 5, except that a biaxially stretched recycled PET film was used as the first stretched plastic film 11 instead of the stretched polypropylene film. The recycled PET film contained 90% or more by mass of PET. The thickness of the recycled PET film of the first stretched plastic film 11 was 12 μm.

[0162] The layer structure of the packaging material 10 of this embodiment is expressed as follows. Recycled PET12 / Stamp / AC / Adhesive Resin / Vapor Deposition / Recycled PET12 / AC / PE(2)30

[0163] Next, the packaging material 10 produced as described above was used to produce a packaging bag 70 shown in Fig. 13 in the same manner as in Example 1. The packaging bag 70 of this example can suitably store regular coffee.

[0164] [Example 7] A laminate including a recycled PET film as the first stretched plastic film 11 and a recycled PET film as the second stretched plastic film 12 was produced in the same manner as in Example 1. Subsequently, a second anchor coat layer 19 was formed on the recycled PET film, and then molten low-density polyethylene was extruded onto the second anchor coat layer 19 to form a sealant layer 15 having a thickness of 30 μm. In this manner, a packaging material 10 was produced.

[0165] The layer structure of the packaging material 10 of this embodiment is expressed as follows. Recycled PET12 / Stamp / Adhesive / Vapor deposition / Recycled PET12 / AC / PE(2)30

[0166] Next, the packaging material 10 produced as described above was used to produce a packaging bag 70 shown in Fig. 13 in the same manner as in Example 1. The packaging bag 70 of this example can suitably store regular coffee.

[0167] [Example 8] A packaging material 10 was produced in the same manner as in Example 7, except that a biaxially stretched nylon film was used instead of the stretched polypropylene film as the first stretched plastic film 11. The nylon film contained 90% by mass or more of polyamide. The thickness of the nylon film of the first stretched plastic film 11 was 15 μm.

[0168] The layer structure of the packaging material 10 of this embodiment is expressed as follows. Nylon 15 / printing / adhesive / metallization / recycled PET12 / AC / PE(2)30 "Nylon" refers to nylon film. As explained in the above embodiment, the rigid film of the first stretched plastic film 11 may be a biaxially stretched PBT film or a biaxially stretched high-stiffness film instead of a nylon film.

[0169] Next, the packaging material 10 produced as described above was used to produce a packaging bag 70 shown in Fig. 13 in the same manner as in Example 1. The packaging bag 70 of this example can suitably contain 100 ml or less of liquid such as miso, noodle soup, or sauce.

[0170] [Example 9] A laminate shown in Fig. 1 was produced in the same manner as in Example 2, except that a biaxially stretched polypropylene film was used instead of the polyethylene film as the sealant layer 15. The stretched polypropylene film contained 90% by mass or more of polypropylene. The thickness of the stretched polypropylene film of the sealant layer 15 can be selected within the range of 20 µm to 40 µm, but was set to 20 µm here.

[0171] The layer structure of the packaging material 10 of this embodiment is expressed as follows. OPP20 / Printing / Adhesive / Vapor Deposition / Recycled PET12 / Adhesive / Heat Seal OPP20 "Heat-sealed OPP" refers to an oriented polypropylene film that has been given sealability by applying a heat-sealing agent.

[0172] Subsequently, a label was produced using the laminate produced as described above.

[0173] The layer structures of the laminates in Examples 1 to 9 are summarized in Table 2 below. [Table 2]

[0174] [Example 10] A biaxially stretched high-stiffness film (hereinafter also referred to as a high-stiffness PET film) having a loop stiffness of 0.0017 N or more and containing 90% by mass or more of PET was prepared as the first stretched plastic film 11. Specifically, XP-55 manufactured by Toray Industries, Inc. was used as the high-stiffness PET film. The high-stiffness film contained 90% by mass or more of PET. The thickness of the high-stiffness PET film was 16 μm. The measured loop stiffness of the high-stiffness PET film was 0.0021 N in both the machine direction and the perpendicular direction. The Young's modulus of the high-stiffness PET film in the machine direction was 4.8 GPa, and the Young's modulus of the high-stiffness PET film in the perpendicular direction was 4.7 GPa. The tensile strength of the high-stiffness PET film in the machine direction was 292 MPa, and the tensile strength of the high-stiffness PET film in the perpendicular direction was 257 MPa. The tensile elongation of the high-stiffness PET film in the machine direction was 107%, and the tensile elongation of the high-stiffness PET film in the perpendicular direction was 102%. In this case, the tensile strength of the high-stiffness PET film in the machine direction divided by the tensile elongation was 2.73 [MPa / %], and the tensile strength of the high-stiffness PET film in the perpendicular direction divided by the tensile elongation was 2.52 [MPa / %]. The heat shrinkage of the high-stiffness PET film in both the machine direction and the perpendicular direction was 0.4%.

[0175] As in Example 1, a biaxially stretched recycled PET film containing PET recycled by mechanical recycling was prepared as the second stretched plastic film 12. The recycled PET film contained 90% or more by mass of PET. The recycled PET film had a thickness of 12 μm. A metal vapor deposition layer 22 made of aluminum and having a thickness of 450 Å was formed on the recycled PET film.

[0176] Next, the high-stiffness PET film and the recycled PET film were bonded together by dry lamination via a first adhesive layer 16 made of an adhesive.

[0177] A polyethylene film containing linear low-density polyethylene was prepared as the sealant layer 15. The thickness of the polyethylene film can be selected within the range of 10 μm to 150 μm, but was set to 120 μm here.

[0178] Next, similarly to Example 1, the laminate including the high-stiffness PET film and the recycled PET film was bonded to the polyethylene film by dry lamination via the second adhesive layer 17 made of an adhesive. In this way, the packaging material 10 was produced.

[0179] The layer structure of the packaging material 10 of this embodiment is expressed as follows. High PET16 / Printing / Adhesive / Vapor Deposition / Recycled PET12 / Adhesive / PE(1)120 "High PET" means high stiffness PET film.

[0180] [Evaluation of puncture resistance] Next, the puncture strength of the packaging material 10 was measured in accordance with JIS Z1707 7.4. A Tensilon universal testing machine RTC-1310 manufactured by A&D was used as the measuring instrument. Specifically, as shown in FIG. 14 , a test piece of the fixed packaging material 10 was pierced from the outer surface 10y side with a semicircular needle 90 having a diameter of 1.0 mm and a tip radius of 0.5 mm at a speed of 50 mm / min (50 mm per minute), and the maximum stress until the needle 90 penetrated the packaging material 10 was measured. The maximum stress was measured for five or more test pieces, and the average value was taken as the puncture strength of the packaging material 10. The measurement was performed in an environment of 23°C and 50% relative humidity. The resulting puncture strength was 16.3 N.

[0181] [Evaluation of tensile properties] The tensile properties of the packaging material 10 were also evaluated in the machine direction and perpendicular directions. Specifically, the Young's modulus of the packaging material 10 was measured in the machine direction and perpendicular directions. The tensile properties of the packaging material 10 can be measured in accordance with JIS K7127. A tensile tester RTC-1310A manufactured by Orientec Co., Ltd. can be used as a measuring instrument. A rectangular film cut from the packaging material with a width of 15 mm and a length of 150 mm can be used as a test piece. The distance between the pair of chucks holding the test piece at the start of the measurement was 50 mm, and the tensile speed was 300 mm / min. The measurement was performed in an environment with a temperature of 25°C and a relative humidity of 50%. As a result, the Young's modulus in the machine direction was 3736 MPa, and the Young's modulus in the perpendicular direction was 3112 MPa. [Explanation of symbols]

[0182] 10 Packaging materials 11 First stretched plastic film 12 Second oriented plastic film 15 Sealant layer 16 1st adhesive layer 17 Second adhesive layer 18 First anchor coat layer 19 Second anchor coat layer 21 Printing layer 22 Metal evaporated layer 30 Recycled Film 31 1st layer 32 2nd layer 33 3rd layer

Claims

1. A laminate comprising at least a first stretched plastic film, a second stretched plastic film, and a sealant layer in this order, The laminate further includes a metal vapor-deposited layer provided on the second stretched plastic film, The first stretched plastic film has a loop stiffness of 0.0017 N or more in at least one direction and contains polyester as a main component, the second stretched plastic film is a recycled film containing recycled polyethylene terephthalate having ethylene glycol as a diol unit and terephthalic acid and isophthalic acid as dicarboxylic acid units, and the content of the isophthalic acid is 0.5 mol% or more and 5 mol% or less relative to all dicarboxylic acid units constituting the recycled polyethylene terephthalate, the Young's modulus of the laminate in one direction, measured in accordance with JIS K7127 at a temperature of 25°C and a relative humidity of 50%, is 3200 MPa or more; The Young's modulus is measured by pulling a rectangular test piece having a width of 15 mm and a length of 150 mm, which is cut out from the laminate, using a pair of chucks at a pulling rate of 300 mm / min. The laminate, wherein the distance between the pair of chucks is 50 mm at the start of measuring the Young's modulus.

2. The laminate according to claim 1 , wherein the sealant layer has a thickness of 18 μm or more and 120 μm or less.

3. 3. The laminate according to claim 1, wherein the recycled polyethylene terephthalate has an intrinsic viscosity of 0.58 dl / g or more and 0.80 dl / g or less.

Images