Laminate and package

Abstract

To provide a package having a laminate capable of manufacturing a packaging bag or the like excellent in recyclability while maintaining heat sealability.SOLUTION: The package of the present invention includes a laminate, wherein the laminate includes a substrate and a heat sealing layer, the substrate is composed of a polyester, the heat sealing layer contains a heat sealing agent, the heat sealing agent contains a low-density polyethylene, a medium-density polyethylene, a high-density polyethylene, a linear low-density polyethylene, or an ethylene-vinyl acetate copolymer, the substrate contains a biomass-derived polyester as the polyester, the content of the polyester in the entire laminate is 60% by mass or more, and the package is a packaging bag or a laminated tube.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate used for producing a package, etc. The present invention also relates to a package including the laminate.

[0002] Conventionally, resin films made of resin materials have been used as materials for forming packaging bodies. For example, polyester films are widely used because they are inexpensive and have excellent mechanical properties, chemical stability, heat resistance, and transparency.

[0003] Typically, a polyester film is laminated with a polyolefin film having heat-sealing properties or a polyamide film having gas barrier properties, and the polyolefin films in the laminate are heat-sealed to produce a package.

[0004] In recent years, with the growing demand for the creation of a recycling-oriented society, high recyclability is being demanded for packaging, etc. However, as mentioned above, conventional packaging bags are made up of different resin materials, and because it is difficult to separate the resin materials, they are not currently recycled. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above problems, and the problem to be solved by the present invention is to provide a laminate that enables the production of packaging bags and the like that are highly recyclable while maintaining heat sealability. Another problem to be solved by the present invention is to provide a package including the laminate. [Means for solving the problem]

[0006] The packaging of the present invention comprises a laminate, the laminate comprising a substrate and a heat seal layer, the substrate being made of polyester, the heat seal layer containing a heat seal agent, the heat seal agent containing low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene or ethylene-vinyl acetate copolymer, the substrate containing a biomass-derived polyester as the polyester, the polyester content in the entire laminate being 60 mass% or more, and the packaging being a packaging bag or a laminate tube.

[0007] In one embodiment, the substrate comprises a vapor-deposited film.

[0008] In one embodiment, an intermediate layer is provided between the substrate and the heat seal layer, and the intermediate layer is made of the same material as the substrate, which is polyester. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a laminate that allows the production of packaging bags and the like that are excellent in recyclability while maintaining heat sealability. Furthermore, the substrate constituting the laminate of the present invention contains a biomass-derived polyester, which allows for a significant reduction in the amount of fossil fuel used and effectively reduces the environmental impact of producing the laminate. Furthermore, according to the present invention, a package including this laminate can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional schematic view showing one embodiment of a laminate according to a first aspect of the present invention. [Figure 2] 1 is a cross-sectional schematic view showing one embodiment of a laminate according to a first aspect of the present invention. [Figure 3] 1 is a cross-sectional schematic view showing one embodiment of a laminate according to a first aspect of the present invention. [Figure 4] FIG. 2 is a cross-sectional schematic view showing one embodiment of a laminate according to a second aspect of the present invention. [Figure 5] FIG. 2 is a cross-sectional schematic view showing one embodiment of a laminate according to a second aspect of the present invention. [Figure 6] FIG. 2 is a cross-sectional schematic view showing one embodiment of a laminate according to a second aspect of the present invention. [Figure 7] 1 is a perspective view illustrating one embodiment of a package including a laminate of the present invention. [Figure 8] 1 is a perspective view illustrating one embodiment of a package including a laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Laminate according to the first aspect) In the first embodiment, the laminate 10 is characterized by comprising a substrate 11 and a heat seal layer 12, as shown in FIG. In one embodiment, as shown in FIG. 2, the laminate of the present invention comprises an adhesive layer 13 between the substrate 11 and the heat seal layer 12 . In one embodiment, as shown in FIG. 3, the laminate 10 of the present invention includes an intermediate layer 14 between the substrate 11 and the heat seal layer 12 . The laminate 10 of the present invention may have two or more intermediate layers 14.

[0012] In the laminate according to the first aspect, the base material and the heat seal layer are made of the same material, polyester. By producing a package using a laminate having such a configuration, the package can be made to have excellent recyclability.

[0013] The content of polyester in the entire laminate of the present invention is preferably 60% by mass or more, more preferably 75% by mass or more, and even more preferably 85% by mass or more. By making the content of polyester in the entire laminate of the present invention 60% by mass or more, the recyclability of the laminate of the present invention can be improved.

[0014] The content of the biomass-derived polyester relative to the polyester contained in the laminate of the present invention is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. By setting the content of the biomass-derived polyester to 80% by mass or more relative to the polyester contained in the laminate of the present invention, it is possible to further improve the reduction of the environmental load.

[0015] Each layer of the laminate according to the first embodiment will be described below.

[0016] (base material) The substrate constituting the laminate of the present invention is characterized by being made of polyester. In the present invention, polyester means a copolymer of a dicarboxylic acid compound and a diol compound. Examples of dicarboxylic acid compounds include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, eicosanedioic acid, pimelic acid, azelaic acid, methylmalonic acid, ethylmalonic acid, adamantanedicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-sodiumsulfoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenanthrenedicarboxylic acid, 9,9'-bis(4-carboxyphenyl)fluorene acid, and ester derivatives thereof. Examples of diol compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, cyclohexanediethanol, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornanedimethanol, norbornanediethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindimethanol, decalindiethanol, 5-methyl-1,3-propanediol ... -methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis(4-hydroxycyclohexylpropane), 2,2-bis(4-(2-hydroxyethoxy)cyclohexyl)propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamantanediol, paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, and pentaerythritol. Furthermore, the polyester may contain a monomer other than the dicarboxylic acid compound and the diol compound, provided that the characteristics of the present invention are not impaired. Among the above, polyethylene terephthalate (hereinafter simply referred to as PET), which is a copolymer of terephthalic acid and ethylene glycol, is preferred.

[0017] The substrate is also characterized in that it contains a biomass-derived polyester as the polyester, in which a diol compound as a copolymerization component is derived from biomass, making it possible to significantly reduce the amount of fossil fuel used and effectively reduce the environmental impact of producing the laminate.

[0018] Biomass-derived diol compounds, such as biomass-derived ethylene glycol, are made from ethanol (biomass ethanol) produced from biomass as a raw material. Biomass-derived ethylene glycol can be obtained by converting biomass ethanol into ethylene oxide using a conventionally known method, or by other methods to produce ethylene glycol. Commercially available biomass ethylene glycol may also be used; for example, biomass ethylene glycol sold by India Glycoal Limited can be suitably used.

[0019] The biomass-derived polyester preferably contains 10 to 25% of biomass-derived carbon based on radiocarbon (C14) measurement relative to the total carbon in the biomass-derived polyester. Atmospheric carbon dioxide contains a certain proportion of C14 (105.5 pMC), and it is known that the C14 content in plants that grow by absorbing atmospheric carbon dioxide, such as corn, is also around 105.5 pMC. It is also known that fossil fuels contain very little C14. Therefore, by measuring the proportion of C14 in the total carbon atoms in biomass-derived polyesters, the proportion of carbon derived from biomass can be calculated. In the present invention, the content of C14 in the biomass-derived polyester is P C14 The content of biomass-derived carbon in this case is P bio is defined as the following formula (1).

number

[0020] For example, PET is made by polymerizing ethylene glycol containing 2 carbon atoms and terephthalic acid containing 8 carbon atoms in a molar ratio of 1:1. Therefore, if only biomass-derived diol units are used as ethylene glycol, the content of biomass-derived carbon in the biomass polyester, P bio is 20%. In this embodiment, the content of biomass-derived carbon, as determined by radiocarbon (C14) measurement, is preferably 10 to 25% of the total carbon in the polyester. If the biomass-derived carbon content in the polyester is less than 10%, the polyester will be less effective as a carbon offset material. On the other hand, as described above, the biomass-derived carbon content in the polyester is preferably as close to 25% as possible. However, due to issues in the film production process and in terms of physical properties, it is preferable to include an additive in the resin composition, so the actual upper limit is 22%.

[0021] That is, when only biomass-derived diol units are used as ethylene glycol, the content of biomass-derived carbon in the biomass-derived polyester, P bio is 20%, and the content of biomass-derived carbon is 10 to 19% of the total carbon in the resin composition. This means that the biomass polyester obtained using biomass-derived ethylene glycol as the diol unit and fossil fuel-derived dicarboxylic acid as the dicarboxylic acid unit is preferably contained in the base material in an amount of 50 (= 10% / 20%) mass % to 100 (= 20% / 20%) mass %.

[0022] In one embodiment, recycled polyester can be used as the polyester constituting the substrate. The recycled polyester of the present invention includes chemically recycled polyester and mechanically recycled polyester. Chemically recycled polyester refers to polyester obtained by decomposing polyester containers down to the monomer level and repolymerizing them. Mechanically recycled polyester refers to polyester obtained by sorting, crushing, and washing polyester containers to remove contaminants and foreign matter, obtaining flakes, and then treating the flakes for a certain period of time under high temperature and reduced pressure to remove contaminants from within the resin.

[0023] The substrate may contain additives within the range that does not impair the properties of the present invention, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0024] The thickness of the substrate is preferably 9 μm or more and 50 μm or less, and more preferably 12 μm or more and 25 μm or less. By making the thickness of the substrate 9 μm or more, the recyclability, heat resistance, and mechanical strength of the laminate of the present invention can be improved. Furthermore, by making the thickness of the substrate 25 μm or less, the processability of the laminate of the present invention can be improved.

[0025] From the viewpoint of heat resistance and strength, the substrate is preferably a stretched film, and may be a uniaxially stretched film or a biaxially stretched film.

[0026] The substrate can be produced by forming a film from a resin composition containing at least a polyester using a casting method, a T-die method, an inflation method, or the like. By forming the film by the inflation method, the resin film can be stretched at the same time.

[0027] The substrate may also be subjected to a surface treatment, which can improve adhesion to adjacent layers. The surface treatment method is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals. Alternatively, an anchor coating layer may be formed on the surface of the substrate using a conventionally known anchor coating agent.

[0028] The substrate may have a printed layer on its surface, and the image formed on the printed layer is not particularly limited, and may be a letter, a pattern, a symbol, or a combination thereof. From the viewpoint of environmental impact, it is preferable that the printing layer be formed on the substrate using ink derived from biomass. The method for forming the printed layer is not particularly limited, and examples thereof include conventionally known printing methods such as gravure printing, offset printing, flexographic printing, etc. Among these, flexographic printing is preferred from the viewpoint of environmental load.

[0029] The substrate may have a vapor-deposited film on its surface. By providing the substrate with a vapor-deposited film, the gas barrier properties, specifically the oxygen barrier properties and water vapor barrier properties, of the laminate of the present invention can be improved. In addition, the weight loss of the contents filled in a package produced using the laminate of the present invention can be suppressed.

[0030] Examples of vapor-deposited films include those composed of metals such as aluminum, and inorganic oxides such as aluminum oxide, silicon oxide (silica), magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

[0031] The thickness of the vapor-deposited film is preferably 1 nm or more and 150 nm or less, more preferably 5 nm or more and 60 nm or less, and even more preferably 10 nm or more and 40 nm or less. By making the thickness of the vapor-deposited film 1 nm or more, the oxygen barrier property and water vapor barrier property of the laminate can be further improved. Also, by making the thickness of the vapor-deposited film 150 nm or less, the occurrence of cracks in the vapor-deposited film can be prevented. Furthermore, the recyclability of the laminate can be maintained.

[0032] The deposition film can be formed on the substrate using a conventionally known method, for example, physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0033] Also, for example, a composite film consisting of two or more layers of vapor-deposited films of different inorganic oxides can be formed and used by combining physical vapor deposition and chemical vapor deposition. The degree of vacuum in the deposition chamber is 10 -2 ~10 -8 After oxygen is introduced, the pressure is preferably about 10 -1 ~10 -6 A pressure of about mbar is preferred. The amount of oxygen introduced varies depending on the size of the deposition machine. An inert gas such as argon gas, helium gas, or nitrogen gas may be used as a carrier gas for the oxygen introduced, provided that this does not cause any problems. The film transport speed can be about 10 to 800 m / min.

[0034] The surface of the deposited film is preferably subjected to the above-mentioned surface treatment, which can improve adhesion to adjacent layers.

[0035] (heat seal layer) In the first aspect, the heat seal layer is made of the same material as the substrate, that is, polyester. Among the polyesters mentioned above, PET is preferred. It is also preferable that the polyester contains a biomass-derived polyester. Furthermore, recycled polyester may be contained in the heat seal layer. Furthermore, the heat seal layer may contain the above-mentioned additives within the range that does not impair the characteristics of the present invention.

[0036] From the viewpoint of heat sealing properties, the heat sealing layer is preferably made of a low-crystalline or amorphous polyester. The crystallinity of the polyester constituting the heat seal layer is preferably 12% or less, and more preferably 10% or less. By making the crystallinity of the polyester 12% or less, the heat sealability can be further improved. In the present invention, the crystallinity of the polyester is determined by dividing the heat of fusion of a low-crystalline or amorphous polyester when melted using a differential scanning calorimeter by the heat of fusion of a completely crystalline polyester (140 J / g for PET), and multiplying the result by 100.

[0037] The glass transition temperature (Tg) of the polyester constituting the heat seal layer is preferably 60°C or higher and 90°C or lower, and more preferably 63°C or higher and 80°C or lower. By adjusting the Tg of the polyester to 90° C. or less, the heat sealability of the heat seal layer can be improved. Furthermore, by setting the Tg of the polyester to 60° C. or higher, it is possible to prevent blocking and other problems from occurring. In the present invention, Tg is a value determined by differential scanning calorimetry in accordance with JIS K 7121.

[0038] In one embodiment, the heat seal layer is formed of a film made of polyester. This film may be a stretched film or an unstretched film, but from the viewpoint of the heat sealability of the heat seal layer, an unstretched film is preferable. Such a film can be produced by utilizing a casting method, a T-die method, an inflation method, or the like. The film-like heat seal layer can be laminated to the substrate via an adhesive as described below.

[0039] In one embodiment, the heat seal layer is formed by a melt-extrusion layer made of polyester.

[0040] The thickness of the heat seal layer is preferably 20 μm or more, more preferably 30 μm or more.

[0041] (adhesive layer) In the first embodiment, the laminate may comprise an adhesive layer between the substrate and the heat seal layer. When the laminate of the present invention has an intermediate layer described below, an adhesive layer may be provided between the substrate and the intermediate layer and between the intermediate layer and the heat seal layer. In this case, the adhesive layers may have the same or different configurations.

[0042] The adhesive layer may be formed from a conventionally known adhesive, which may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be either a solvent-free adhesive or a solvent-based adhesive, but from the viewpoint of environmental load, a solvent-free adhesive is preferably used. Examples of solvent-free adhesives include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives, and among these, two-component curing urethane adhesives can be preferably used. Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives. Among the above, from the viewpoint of the recyclability of the laminate of the present invention, polyester-based adhesives are preferred, and PET-based adhesives are more preferred. For example, PET adhesives include Elitel KT-0507, KT-8904, KT8701, KT-9204 and KT-8803 manufactured by Unitika Ltd.

[0043] In one embodiment, the adhesive layer may include an oxygen absorber. The oxygen absorbent is not particularly limited, and may be an inorganic compound or an organic compound, and can be appropriately selected depending on the purpose. Examples of inorganic compounds include metal powders such as iron powder, titanium dioxide, cerium oxide, ferrous salts, dithionites, sulfites, metal halides, zeolites, etc. Examples of organic compounds include benzenetriol, polyhydric phenol compounds, polyhydric alcohol compounds, ascorbic acid compounds, cyclohexene compounds, polyene polymers having unsaturated double bonds, ethylene-vinyl alcohol copolymers, etc., and mixtures thereof.

[0044] The adhesive layer may contain additives such as pigments such as titanium dioxide, zinc oxide and carbon black, dyes such as disperse dyes, acid dyes and cationic dyes, antioxidants, lubricants, colorants, stabilizers, wetting agents, thickeners, coagulants, gelling agents, anti-settling agents, softeners, hardeners, plasticizers, leveling agents, ultraviolet absorbers and flame retardants, as long as the properties of the present invention are not impaired.

[0045] The thickness of the adhesive layer is preferably 1 μm or more, and more preferably 6 μm or more. Furthermore, when the adhesive layer is made of an adhesive material other than a polyester-based adhesive, the thickness is preferably 5 μm or less, and more preferably 3 μm or less. By making the thickness of the adhesive layer 1 μm or more, the adhesion between the layers can be improved. Furthermore, when the adhesive layer is made of an adhesive material other than a polyester-based adhesive, the recyclability of the laminate of the present invention can be improved by making the thickness 5 μm or less.

[0046] (middle class) In one embodiment, the laminate of the present invention comprises an intermediate layer between the substrate and the heat seal layer, and this intermediate layer is made of the same material as the substrate, i.e., polyester. By adopting such a configuration, the recyclability, heat resistance, and strength of the present invention can be further improved.

[0047] The intermediate layer is made of the above-mentioned polyester, and is preferably made of PET. The intermediate layer preferably contains a biomass-derived polyester. The middle layer may also include recycled polyester. Furthermore, the intermediate layer may contain the above-mentioned additives within the range that does not impair the characteristics of the present invention.

[0048] The thickness of the intermediate layer is preferably 9 μm or more and 50 μm or less, and more preferably 12 μm or more and 25 μm or less. By making the thickness of the intermediate layer 9 μm or more, the recyclability, heat resistance and mechanical strength of the laminate of the present invention can be improved. Furthermore, by making the thickness of the intermediate layer 50 μm or less, the processability of the laminate of the present invention can be improved.

[0049] From the viewpoint of heat resistance and strength, the intermediate layer is preferably a stretched film, and may be a uniaxially stretched film or a biaxially stretched film.

[0050] The intermediate layer can be formed by forming a film from a resin composition containing at least a polyester using a casting method, a T-die method, an inflation method, or the like, and laminating this to a substrate via an adhesive layer. Alternatively, the intermediate layer can be formed by melt-extruding the resin composition onto the substrate.

[0051] The intermediate layer may be subjected to a surface treatment in order to improve adhesion to the adjacent layer. The intermediate layer may also have a printed layer and / or a vapor-deposited film on its surface.

[0052] (barrier coat layer) When the laminate of the present invention comprises a vapor-deposited film made of an inorganic oxide, it can comprise a barrier coat layer adjacent to this vapor-deposited film. As a specific example, the laminate of the present invention includes a substrate, an inorganic oxide vapor deposition film, a barrier coat layer, an adhesive layer, and a heat seal layer in this order. By adopting such a configuration, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be improved. Furthermore, the occurrence of cracks in the vapor-deposited film can be effectively prevented.

[0053] In one embodiment, the barrier coat layer is a gas barrier coating film containing at least one resin composition such as a hydrolyzate of a metal alkoxide or a hydrolyzed condensate of a metal alkoxide obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer by a sol-gel method in the presence of a sol-gel catalyst, water, an organic solvent, etc.

[0054] In one embodiment, the metal alkoxide is represented by the following general formula: R 1 n M(OR 2 ) m (wherein, R 1 , R 2 each represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the valence of M.

[0055] As the metal atom M, for example, silicon, zirconium, titanium, aluminum, etc. can be used. Also, R 1 and R 2 Examples of the organic group represented by the formula (I) include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group.

[0056] Examples of metal alkoxides that satisfy the above general formula include tetramethoxysilane (Si(OCH3)4), tetraethoxysilane (mass %) Si(OC2H5)4), tetrapropoxysilane (Si(OC3H7)4), and tetrabutoxysilane (Si(OC4H9)4).

[0057] It is also preferable to use a silane coupling agent together with the metal alkoxide. As the silane coupling agent, known organoalkoxysilanes containing organic reactive groups can be used, but organoalkoxysilanes having epoxy groups are particularly preferred. Examples of organoalkoxysilanes having epoxy groups include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0058] Two or more of the above silane coupling agents may be used, and the silane coupling agent is preferably used in an amount of about 1 to 20 parts by mass per 100 parts by mass of the total amount of the alkoxides.

[0059] As the water-soluble polymer, polyvinyl alcohol and ethylene-vinyl alcohol copolymer are preferred, and from the viewpoints of oxygen barrier property, water vapor barrier property, water resistance and weather resistance, it is preferred to use these in combination.

[0060] The content of the water-soluble polymer in the gas barrier coating film is preferably 5 parts by mass or more and 500 parts by mass or less per 100 parts by mass of the metal alkoxide. By adjusting the content of the water-soluble polymer in the gas barrier coating film to 5 parts by mass or more per 100 parts by mass of the metal alkoxide, the oxygen barrier property and water vapor barrier property of the laminate can be further improved. Also, by adjusting the content of the water-soluble polymer in the gas barrier coating film to 500 parts by mass or less per 100 parts by mass of the metal alkoxide, the film formability of the gas barrier coating film can be improved.

[0061] The thickness of the gas barrier coating film is preferably 0.01 μm or more and 2 μm or less, and more preferably 0.1 μm or more and 1 μm or less. By making the thickness of the gas barrier coating film 0.01 μm or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be improved. Furthermore, by making the thickness of the gas barrier coating film 2 μm or less, the recyclability of the laminate of the present invention can be improved.

[0062] The gas barrier coating film can be formed by applying a composition containing the above-mentioned materials by a conventionally known means such as roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brush coating, bar coating, or applicator coating, and then polycondensing the composition by a sol-gel method. The sol-gel catalyst is preferably an acid or an amine compound. As the amine compound, a tertiary amine that is substantially insoluble in water and soluble in an organic solvent is preferred, such as N,N-dimethylbenzylamine, tripropylamine, tributylamine, tripentylamine, etc. Among these, N,N-dimethylbenzylamine is preferred. The sol-gel catalyst is preferably used in the range of 0.01 to 1.0 part by mass, more preferably 0.03 to 0.3 part by mass, per 100 parts by mass of the metal alkoxide. By using a sol-gel catalyst in an amount of 0.01 part by mass or more per 100 parts by mass of metal alkoxide, the catalytic effect can be improved, and by using a sol-gel catalyst in an amount of 1.0 part by mass or less per 100 parts by mass of metal alkoxide, the thickness of the gas barrier coating film formed can be made uniform.

[0063] The composition may further contain an acid, which is used as a catalyst in the sol-gel process, mainly for the hydrolysis of alkoxides, silane coupling agents, and the like. The acid may be a mineral acid such as sulfuric acid, hydrochloric acid, or nitric acid, or an organic acid such as acetic acid or tartaric acid. The amount of the acid used is preferably 0.001 mol or more and 0.05 mol or less based on the total molar amount of the alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent. The catalytic effect can be improved by using an acid in an amount of 0.001 mole or more relative to the total molar amount of the alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent. Also, the thickness of the gas barrier coating film formed can be made uniform by using an acid in an amount of 0.05 mole or less relative to the total molar amount of the alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent.

[0064] The composition preferably contains water in an amount of 0.1 to 100 moles, more preferably 0.8 to 2 moles, per mole of the total molar amount of the alkoxides. By adjusting the water content to 0.1 mol or more per mol of the total molar amount of alkoxide, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be improved. Also, by adjusting the water content to 100 mol or more per mol of the total molar amount of alkoxide, the hydrolysis reaction can be carried out quickly.

[0065] The composition may also contain an organic solvent, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, or n-butanol.

[0066] An embodiment of the method for forming a gas barrier coating film will be described below. First, a composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and optionally a silane coupling agent, etc. A polycondensation reaction gradually proceeds in the composition. The composition is then applied to a substrate by the above-mentioned conventional method and dried, which further promotes the polycondensation reaction of the alkoxide and the water-soluble polymer (and the silane coupling agent, if the composition contains one) to form a composite polymer layer. Finally, the composition is heated at a temperature of 20 to 250°C, preferably 50 to 220°C, for 1 second to 10 minutes to form a gas barrier coating film.

[0067] The barrier coat layer may have a printed layer formed thereon, and the method for forming the printed layer is as described above.

[0068] The barrier coat layer may contain the above-mentioned additives to the extent that the properties of the present invention are not impaired.

[0069] (Laminate according to the second aspect) In the second embodiment, as shown in FIG. 4, the laminate 20 is characterized by comprising a substrate 21 and a heat seal layer 22 containing a heat seal agent. In one embodiment, as shown in FIG. 5, a substrate 21 includes a deposited film 23 . In one embodiment, as shown in FIG. 6, the laminate 20 of the present invention includes an intermediate layer 24 between the substrate 21 and the heat seal layer 22. Furthermore, in one embodiment, as shown in FIG. 7, the laminate 20 of the present invention includes an adhesive layer 25 between the substrate 21 and the intermediate layer 24 as shown in FIG. The laminate 20 of the present invention may have two or more intermediate layers 24.

[0070] In the second embodiment, the ratio of the thickness of the substrate to the thickness of the entire laminate is preferably 60% or more, and more preferably 70% or more. By making the ratio of the thickness of the substrate to the total thickness of the laminate of the present invention 60% or more, the recyclability of the laminate of the present invention can be improved.

[0071] In the second embodiment, the content of polyester in the entire laminate is preferably 60% by mass or more, and more preferably 70% by mass or more. By making the content of polyester in the entire laminate of the present invention 60% by mass or more, the recyclability of the laminate of the present invention can be improved.

[0072] The content of the biomass-derived polyester relative to the polyester contained in the laminate of the present invention is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more. By setting the content of the biomass-derived polyester to 80% by mass or more relative to the polyester contained in the laminate of the present invention, it is possible to further improve the reduction of the environmental load.

[0073] Each layer of the laminate according to the second embodiment will be described below. The substrate, intermediate layer, adhesive layer, and barrier coat layer are the same as those in the first embodiment, and therefore descriptions thereof will be omitted here.

[0074] (heat seal layer) The heat seal layer can be formed by a heat seal agent containing a resin that can be fused to each other by heat, and examples thereof include low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), ethylene-α-olefin copolymer polymerized using a metallocene catalyst, ethylene-polypropylene random or block copolymer, polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene Examples of suitable resins include ethylene-methyl methacrylate copolymers (EMMA), ionomer resins, heat-sealable ethylene-vinyl alcohol resins, or copolymerized resins such as methylpentene resins, ethylene-propylene copolymers, methylpentene polymers, polybutene polymers, polyolefins such as polyethylene, polypropylene, or cyclic olefin copolymers, acid-modified polyolefins obtained by modifying polyolefins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, polyesters such as PET, polyvinyl acetate resins, poly(meth)acrylic resins, and polyvinyl chloride resins. Among these, from the viewpoint of the recyclability of the laminate of the present invention, it is preferable to form the heat seal layer using a polyester-based heat seal agent, in particular a PET-based heat seal agent. The heat sealing agent that forms the heat seal layer may be a commercially available product, and examples of PET-based heat sealing agents include Elitel KT-0507, KT-8904, KT8701, KT-9204, and KT-8803 manufactured by Unitika Ltd.

[0075] The number average molecular weight (Mn) of the resin contained in the heat sealing agent that forms the heat seal layer is preferably 10,000 or more and 35,000 or less, and more preferably 12,000 or more and 25,000 or less. By making the Mn of the resin 10,000 or more, the ease of forming the heat seal layer can be improved. Furthermore, by making the Mn of the resin 35,000 or less, the heat sealability of the heat seal layer can be improved. In the present invention, Mn means a value measured by gel permeation chromatography using polystyrene as a standard substance, and is measured by a method in accordance with JIS K 7252-1.

[0076] The thickness of the heat seal layer is preferably 1 μm or more, and more preferably 3 μm or more. When the heat seal layer is made of a resin other than polyester, the thickness thereof is preferably 10 μm or less, and more preferably 5 μm or less. By making the thickness of the heat seal layer 1 μm or more, the heat sealability of the laminate of the present invention can be improved. Furthermore, when the heat seal layer is made of a resin other than polyester, the recyclability of the laminate of the present invention can be improved by making the thickness of the heat seal layer 10 μm or less.

[0077] The heat seal layer can be formed by utilizing a dry lamination method, a melt extrusion lamination method, or the like.

[0078] (packaging) The packaging body of the present invention is characterized by comprising the laminate. Examples of the packaging body include packaging products (packaging bags), lids, and laminate tubes.

[0079] Examples of packaging bags include various types of packaging bags such as a standing pouch type, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a palm seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type.

[0080] A standing pouch, which is an example of a package including the laminate of the present invention, will be described. Fig. 7 is a diagram showing a simplified example of the configuration of a stand-up pouch. As shown in Fig. 7, stand-up pouch 30 is composed of a body portion (side sheets) 31 and a bottom portion (bottom sheet) 32. Side sheets 31 and bottom sheet 32 ​​of stand-up pouch 30 may be composed of the same material, or may be composed of different materials.

[0081] In one embodiment, the body 31 of the standing pouch 30 can be formed by bag making so that the heat seal layer of the laminate of the present invention is the innermost layer. In another embodiment, body 31 can be formed by preparing two laminates of the present invention, overlapping them with their heat-sealable layers facing each other, inserting two V-shaped laminates into both ends of the overlapped laminate with their heat-sealable layers facing outward, and heat-sealing the resulting laminate. This production method can produce a stand-up pouch having a body with gussets 33 as shown in Fig. 8.

[0082] In one embodiment, the bottom sheet 32 ​​of the standing pouch 30 can be formed by inserting the laminate of the present invention between pre-formed side sheets and heat sealing them. More specifically, the laminate can be formed by folding it into a V shape so that the heat seal layer faces outward, inserting it between side sheets that have been made into a bag, and heat sealing it.

[0083] 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.

[0084] The contents filled in the package are not particularly limited, and may be liquid, powder, or gel, and may be food or non-food.

[0085] (Other aspects) In another aspect, the laminate of the present invention comprises a substrate and a heat seal layer, wherein the substrate is made of polyester and the polyester contained in the substrate is a biomass-derived polyester. In one embodiment of this aspect, the heat seal layer is made of the same material as the substrate, The same material is polyester. In one embodiment of the other aspect, the heat seal layer contains a biomass-derived polyester as the polyester. In one embodiment of the other aspect, an adhesive layer is provided between the substrate and the heat seal layer, and the adhesive layer is made of a polyester-based adhesive. In another aspect, the laminate of the present invention comprises a substrate and a heat seal layer, wherein the substrate is made of polyester, the heat seal layer contains a heat seal agent, and the substrate contains a biomass-derived polyester as the polyester. In one embodiment of the other aspect, the heat seal layer comprises a polyester-based heat seal agent. In one embodiment of the other aspect, the substrate comprises a vapor-deposited film. In one embodiment of the other aspect, an intermediate layer is provided between the substrate and the heat seal layer, and the intermediate layer is made of the same material as the substrate, which is polyester. In one embodiment of this other aspect, the content of polyester in the entire laminate is 60% by mass or more. In one embodiment of the other aspect, the laminate of the present invention is used in packaging applications. A packaging body according to another aspect of the present invention is characterized by comprising the above-mentioned laminate. [Example]

[0086] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0087] Example 1-1 As a substrate, a biaxially stretched biomass PET film (manufactured by Dai Nippon Printing Co., Ltd., trade name Biomatec PET, biomass content 20%) having a thickness of 12 μm and having one surface subjected to a corona treatment was prepared. A print layer was formed on the corona treated surface of this PET film by gravure printing.

[0088] PET1 (Vylon SI-173, manufactured by Toyobo Co., Ltd., Tg: 78°C) was cast to produce a 20 μm-thick unstretched film for a heat-seal layer. This unstretched film for a heat-seal layer was laminated onto the surface of the substrate on which the printing layer was formed via a two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-40 / curing agent H-4) to obtain a laminate of the present invention.

[0089] Example 1-2 A laminate of the present invention was produced in the same manner as in Example 1, except that the unstretched film for the heat-sealing layer was changed to a 20 μm thick stretched film for the heat-sealing layer (manufactured by Toyobo Co., Ltd., Polyester DE046, Tg: 65°C).

[0090] Examples 1-3 As a substrate, a 12 μm-thick biaxially stretched biomass PET film (manufactured by Dai Nippon Printing Co., Ltd., trade name Biomatec PET, biomass content 20%) with a silica vapor deposition film formed on one side was prepared. A print layer was formed on the vapor-deposited surface of this PET film by gravure printing.

[0091] An unstretched film for a heat seal layer made of PET1 (Vylon SI-173, manufactured by Toyobo Co., Ltd.) prepared in Example 1 was laminated onto the surface of the substrate on which the vapor deposition layer was formed via a two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-40 / curing agent H-4) to obtain a laminate of the present invention.

[0092] Examples 1-4 A laminate was obtained in the same manner as in Example 1, except that the substrate and the heat seal layer were laminated via a PET emulsion (Elitel KT-0507, manufactured by Unitika Ltd.).

[0093] Comparative Example 1-1 A 12 μm-thick biaxially stretched biomass PET film (trade name Biomatec PET, biomass content 20%, manufactured by Dai Nippon Printing Co., Ltd.) with one side corona-treated was prepared as the substrate. A print layer was formed on the corona-treated side of this PET film by gravure printing.

[0094] A two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-40 / hardener H-4) was applied to the printed layer formed as described above and dried to form a 3 μm thick adhesive layer, and a 30 μm thick LLDPE film was laminated as a heat seal layer to obtain a laminate.

[0095] <<Recyclability evaluation>> The PET content in the entire laminates produced in the above Examples and Comparative Examples was determined, and the recyclability was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1. (Evaluation criteria) A: The PET content in the entire laminate was 70% by mass or more. NG: The PET content in the entire laminate was less than 70% by mass.

[0096] <<Heat seal strength test-1>> The laminates produced in the above Examples and Comparative Examples were cut into a size of 220 mm length x 130 mm width. Two laminates cut as described above were stacked together with the heat seal layers facing each other, and a laminate prepared in the above Examples and Comparative Examples was folded in a V shape from one end of the body so that the heat seal layer was on the outside and sandwiched between the two. Next, the two vertical sides and the side sandwiching the V-shaped laminate were heat-sealed (140° C., 1 kgf, 1 second).

[0097] This packaging bag was filled with 300 mL of liquid detergent, and the remaining side was heat-sealed (140°C, 1 kgf, 1 second) to form a package.

[0098] The above-mentioned package was dropped ten times from a height of 100 cm onto a hard floor with the body of the package held horizontally to the ground. This test was carried out for 10 bags at a time, and the presence or absence of damage was visually observed. The heat sealability was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1. (Evaluation criteria) A: No damage was found in any of the 10 bags. NG: Breakage was confirmed in one or more of the 10 bags, posing a practical problem.

[0099] <<Heat seal strength test-2>> Two laminates prepared in the above Examples and Comparative Examples were stacked together with the heat seal layers facing each other, and heat sealed (140° C., 1 kgf, 1 second). The seal strength was then measured using a tensile tester. The measurement results are summarized in Table 1.

[0100] [Table 1]

[0101] As is clear from the results in Table 1, it is understood that the laminate of the present invention makes it possible to produce a packaging bag that is excellent in recyclability while maintaining heat sealability.

[0102] Example 2-1 As a substrate, a biaxially stretched biomass PET film (manufactured by Dai Nippon Printing Co., Ltd., trade name Biomatec PET, biomass content 20%) having a thickness of 12 μm and having one surface subjected to a corona treatment was prepared. A print layer was formed on the corona treated surface of this PET film by gravure printing.

[0103] An ethylene-vinyl acetate copolymer emulsion (Seikadyne 1900w, manufactured by Dainichi Seika Color & Chemicals Mfg. Co., Ltd.) was applied as a heat seal agent onto the printed layer formed as described above and dried to form a heat seal layer 3 μm thick, thereby obtaining a laminate of the present invention.

[0104] Example 2-2 As a substrate, a biaxially stretched biomass PET film (manufactured by Dai Nippon Printing Co., Ltd., trade name Biomatec PET, biomass content 20%) having a thickness of 12 μm and having one surface subjected to a corona treatment was prepared. A print layer was formed on the corona treated surface of this PET film by gravure printing.

[0105] A two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-40 / hardener H-4) was applied to the printed layer formed as described above and dried to form a 3 μm thick adhesive layer, and a 12 μm thick biaxially oriented PET film with corona treatment on both sides was laminated as an intermediate layer.

[0106] An ethylene-vinyl acetate copolymer emulsion (Seikadyne 1900w, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) was applied as a heat seal agent to the other side of the PET film serving as the intermediate layer, and dried to form a 3 μm thick heat seal layer, thereby obtaining a laminate of the present invention.

[0107] Example 2-3 As a substrate, a 12 μm-thick biaxially stretched biomass PET film (manufactured by Dai Nippon Printing Co., Ltd., trade name Biomatec PET, biomass content 20%) with a silica vapor deposition film formed on one side was prepared. A print layer was formed on the vapor-deposited surface of this PET film by gravure printing.

[0108] The two-component curing urethane adhesive was applied to the printed layer formed as described above and dried to form a 3 μm thick adhesive layer, and a 12 μm thick biaxially oriented PET film that had been corona treated on both sides was laminated as an intermediate layer.

[0109] An ethylene-vinyl acetate copolymer emulsion (Seikadyne 1900w, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) was applied as a heat seal agent to the other side of the PET film serving as the intermediate layer, and dried to form a 3 μm thick heat seal layer, thereby obtaining a laminate of the present invention.

[0110] Examples 2-4 A laminate was obtained in the same manner as in Example 2, except that the PET film used in the intermediate layer was changed to a 12 μm thick biaxially oriented biomass PET film (manufactured by Dai Nippon Printing Co., Ltd., product name Biomatec PET, biomass content 20%) that had been corona treated on both sides.

[0111] Examples 2-5 A laminate was obtained in the same manner as in Example 2, except that a polyethylene emulsion (Arrowbase SD-1205-J2, manufactured by Unitika Ltd.) was used as the heat sealing agent.

[0112] Examples 2-6 A laminate was obtained in the same manner as in Example 2, except that a PET emulsion (manufactured by Unitika Ltd., Elitel KT-0507, Mn 17000, Tg -25°C) was used as the heat sealing agent.

[0113] Comparative Example 2-1 A 12 μm-thick biaxially stretched biomass PET film (trade name Biomatec PET, biomass content 20%, manufactured by Dai Nippon Printing Co., Ltd.) with one side corona-treated was prepared as the substrate. A print layer was formed on the corona-treated side of this PET film by gravure printing.

[0114] A two-component curing urethane adhesive (manufactured by Rock Paint Co., Ltd., product name: RU-40 / hardener H-4) was applied to the printed layer formed as described above and dried to form a 3 μm thick adhesive layer, and a 30 μm thick LLDPE film was laminated as a heat seal layer to obtain a laminate.

[0115] <<Performance evaluation>> The recyclability and heat sealability were evaluated in the same manner as described above, and the evaluation results are summarized in Table 2.

[0116] [Table 2]

[0117] As is clear from the results in Table 2, it is understood that the laminate of the present invention makes it possible to produce a packaging bag that is excellent in recyclability while maintaining heat sealability. [Explanation of symbols]

[0118] 10, 20: laminate, 11, 21: substrate, 12, 22: heat seal layer, 13: adhesive layer, 14, 24: intermediate layer, 15, 25: adhesive layer, 23: vapor deposition film, 30: standing pouch, 31: body portion, 32: bottom portion, 33: gusset

Claims

1. A package comprising a laminate, The laminate comprises a substrate and a heat seal layer, The substrate is made of polyester, the heat seal layer comprises a heat seal agent; the heat-sealing agent comprises low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, or ethylene-vinyl acetate copolymer; the substrate contains a biomass-derived polyester as the polyester, The content of polyester in the entire laminate is 60% by mass or more, The packaging body is a packaging bag or a laminated tube.

2. The package of claim 1 , wherein the substrate comprises a vapor-deposited film.

3. An intermediate layer is provided between the substrate and the heat seal layer, the intermediate layer is made of the same material as the base material, 3. The package of claim 1, wherein the same material is polyester.

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