Laminate and packaging bag

Abstract

To provide a laminate that enables production of a packaging bag which has sufficient strength and heat resistance and is excellent in recyclability and gas barrier property.SOLUTION: A laminate includes a base material and a sealant layer, in which the base material and the sealant layer are composed of the same material, the base material is subjected to at least one of stretching treatment and electron beam irradiation treatment, the same material is polyethylene or polypropylene, and a barrier coat layer is provided between the base material and the sealant layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate used for producing a packaging bag etc. The present invention also relates to a packaging bag made of the laminate.

[0002] Conventionally, resin films made of resin materials have been used as materials for forming packaging bags. For example, resin films made of polyolefins have suitable flexibility and transparency, as well as excellent heat-sealing properties, and are therefore widely used for packaging bags.

[0003] Typically, resin films made from polyolefins are inferior in strength and heat resistance and therefore cannot be used as a base material for constructing packaging bags, etc., and are instead used by laminating them with resin films made from polyester, polyamide, etc. For this reason, ordinary packaging bags are constructed from a laminate in which the base material and sealant layer are made from different types of resin materials (for example, Patent Document 1).

[0004] In recent years, with the growing demand for the creation of a recycling-oriented society, there has been a demand for high recyclability in packaging bags, 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. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-202519 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors have discovered that by subjecting a polyethylene film or a polypropylene film to at least one of a stretching treatment and an electron beam irradiation treatment, the strength and heat resistance of the film can be significantly improved, making it possible to use the film as a substrate in a laminate used in the production of packaging bags, etc. They have also discovered that by forming the sealant layer from a polyolefin, like the substrate, the recyclability of the laminate can be significantly improved. Furthermore, the inventors have discovered that by further providing a barrier coat layer, the oxygen barrier properties and water vapor barrier properties (gas barrier properties) of the contents filled in a packaging bag made using the laminate of the present invention can be significantly improved.

[0007] The present invention has been made in light of the above findings, 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 have sufficient strength and heat resistance, and also have excellent recyclability and gas barrier properties.

[0008] Another problem to be solved by the present invention is to provide a packaging bag made from the laminate. [Means for solving the problem]

[0009] The laminate of the present invention comprises a substrate and a sealant layer, the substrate and the sealant layer are made of the same material; the substrate has been subjected to at least one of a stretching treatment and an electron beam irradiation treatment; The same material is polyethylene or polypropylene, It is characterized by having a barrier coating layer between the substrate and the sealant layer.

[0010] In one embodiment, the barrier coat layer is a gas barrier coating film containing at least one metal alkoxide hydrolysate or metal alkoxide hydrolysis condensate obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer by a sol-gel method.

[0011] In one embodiment, the thickness of the barrier coat layer is 0.01 μm or more and 100 μm or less.

[0012] In one embodiment, a vapor-deposited film is provided between the substrate and the barrier coat layer, or between the barrier coat layer and the sealant layer.

[0013] In one embodiment, the deposited film is composed of an inorganic oxide.

[0014] In one embodiment, the laminate is used for packaging bags.

[0015] The packaging bag of the present invention is characterized by being formed from the above-mentioned laminate.

[0016] In one embodiment, the packaging bag includes a spout. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a laminate that allows the production of packaging bags and the like that have sufficient strength and heat resistance, and are also excellent in recyclability and gas barrier properties. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional schematic view showing one embodiment of a laminate of the present invention. [Figure 2] 1 is a cross-sectional schematic view showing one embodiment of a laminate of the present invention. [Figure 3] 1 is a cross-sectional schematic view showing one embodiment of a laminate of the present invention. [Figure 4] 1 is a perspective view showing one embodiment of a packaging bag produced using the laminate of the present invention. [Figure 5] 1 is a front view showing one embodiment of a packaging bag produced using a laminate of the present invention. [Figure 6] 1 is a front view showing one embodiment of a packaging bag produced using a laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] (Laminate) As shown in FIG. 1, the laminate 10 of the present invention is characterized by comprising a substrate 11 and a sealant layer 12. In one embodiment, the laminate 10 includes a barrier coat layer 13 between a substrate 11 and a sealant layer 12, as shown in FIG. In one embodiment, the laminate 10 also includes a vapor-deposited film (not shown) between the substrate and the barrier coat layer or between the barrier coat layer and the sealant layer. In one embodiment, the laminate 10 includes a light-blocking printed layer 14 between the barrier coat layer 13 and the sealant layer 12, as shown in FIG. Furthermore, in one embodiment, the sealant 12 included in the laminate 10 includes a light-shielding layer 15, as shown in Figure 3. In this embodiment, the sealant layer 12 can also include a laminating layer 16 and a heat-sealing layer 17. In the present invention, the substrate and the sealant layer are made of the same material, namely polyethylene or polypropylene, which can improve the recyclability of the laminate.

[0020] The laminate of the present invention may also include an adhesive layer (not shown) between any of the layers, for example, between the barrier coat layer and the sealant layer. Additionally, the laminate of the present invention may include an intermediate layer (not shown) between the substrate and the sealant layer.

[0021] (base material) The substrate constituting the laminate of the present invention is made of polyethylene or polypropylene, and is characterized by having been subjected to at least one of a stretching treatment and an electron beam irradiation treatment. By carrying out the stretching treatment and electron beam irradiation treatment, the heat resistance and strength of the substrate can be significantly improved, and the physical properties required for the outer layer of a packaging bag or the like can be satisfied. When the substrate has been subjected to electron beam irradiation treatment, the substrate is provided so that the surface of the substrate that has been irradiated with electron beams becomes the outermost surface of the laminate.

[0022] As the polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene and very low density polyethylene can be used. Among these, high density polyethylene and medium density polyethylene are preferred from the viewpoint of the strength and heat resistance of the substrate, and medium density polyethylene is more preferred from the viewpoint of the stretchability.

[0023] In the present invention, the high density polyethylene has a density of 0.945 g / cm 3 The polyethylene having a density of 0.925 g / cm or more can be used. 3 More than 0.945g / cm 3 Low density polyethylene can be used, and low density polyethylene is polyethylene with a density of 0.900 g / cm 3 More than 0.925g / cm 3 Polyethylenes with a density of less than 0.900 g / cm can be used, and linear low-density polyethylenes with a density of less than 0.900 g / cm can be used. 3 More than 0.925g / cm 3 Polyethylene with a density of less than 0.900 g / cm can be used, and ultra-low density polyethylene has a density of 0.900 g / cm 3 Less than 100% polyethylene can be used.

[0024] Furthermore, as long as the properties of the present invention are not impaired, copolymers of ethylene and other monomers can also be used as polyethylene. Examples of ethylene copolymers include copolymers of ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene. Furthermore, as long as the properties of the present invention are not impaired, copolymers with vinyl acetate or acrylic esters, etc., may also be used.

[0025] In the present invention, the substrate preferably contains biomass-derived polyethylene. Biomass-derived polyethylene is a material that uses biomass-derived ethylene as a raw material instead of ethylene obtained from fossil fuels. Since such biomass-derived polyethylene is a carbon-neutral material, the environmental impact of producing the laminate can be reduced. Such biomass-derived polyethylene can be produced, for example, by a method such as that described in JP 2013-177531 A. Alternatively, commercially available biomass-derived polyethylene (e.g., Green PE available from Braskem) may be used.

[0026] It is also possible to use polyethylene recycled through mechanical recycling, which generally involves crushing collected polyethylene film and washing it with an alkali to remove dirt and foreign matter from the film surface, and then drying it at high temperature and reduced pressure for a certain period of time to diffuse any contaminants remaining inside the film, thereby decontaminating it and removing the dirt from the polyethylene film and returning it to polyethylene.

[0027] When a packaging bag made from the laminate of the present invention is filled with contents and subjected to retort treatment, the base material and sealant layer are preferably made of polypropylene from the viewpoint of suitability for retort treatment. The polypropylene may be a homopolymer, a random copolymer, or a block copolymer. A polypropylene homopolymer is a polymer of only propylene, a polypropylene random copolymer is a random copolymer of propylene and an α-olefin other than propylene (e.g., ethylene, butene-1, 4-methyl-1-pentene, etc.), and a polypropylene block copolymer is a copolymer having a polymer block made of propylene and a polymer block made of the above-mentioned α-olefin other than propylene. Among these polypropylenes, it is preferable to use a homopolymer or a random copolymer, from the viewpoint of improving the transparency of the substrate and improving the visibility of an image formed on the adhesive layer side surface of the substrate. When importance is placed on the rigidity and heat resistance of the packaging bag, a homopolymer can be used, and when importance is placed on impact resistance, a random copolymer can be used.

[0028] It is also possible to use biomass-derived polypropylene or polypropylene recycled by mechanical recycling.

[0029] 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.

[0030] The substrate may have a single layer structure or a multilayer structure. In one embodiment, the substrate has a multilayer structure including a layer made of high-density polyethylene (hereinafter referred to as high-density polyethylene layer), a layer made of medium-density polyethylene (hereinafter referred to as medium-density polyethylene layer), and a layer made of high-density polyethylene (hereinafter referred to as high-density polyethylene layer). By adopting such a configuration, it is possible to further improve the strength and heat resistance of the substrate, prevent the occurrence of curling in the substrate, and improve the stretchability of the substrate. In this case, the thickness of the high density polyethylene layer is preferably thinner than the thickness of the medium density polyethylene layer. The ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer is preferably 1 / 10 or more and 1 / 1 or less, and more preferably 1 / 5 or more and 1 / 2 or less. By setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer to 1 / 10 or more, the strength and heat resistance of the substrate can be further improved. Also, by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer to 1 / 1 or less, the stretchability of the substrate can be further improved.

[0031] In one embodiment, the substrate comprises a high-density polyethylene layer, a medium-density polyethylene layer, a low-density polyethylene layer, a linear low-density polyethylene layer, or an ultra-low-density polyethylene layer (collectively referred to as a low-density polyethylene layer in this paragraph for the sake of simplicity), a medium-density polyethylene layer, and a high-density polyethylene layer. By adopting such a configuration, it is possible to improve the stretchability of the substrate, improve the strength and heat resistance of the substrate, prevent the occurrence of curling in the substrate, and improve the production efficiency of the substrate. In this case, the thickness of the high density polyethylene layer is preferably thinner than the thickness of the medium density polyethylene layer. The ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer is preferably 1 / 10 or more and 1 / 1 or less, and more preferably 1 / 5 or more and 1 / 2 or less. By setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer to 1 / 10 or more, the strength and heat resistance of the substrate can be improved, and by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer to 1 / 1 or less, the stretchability of the substrate can be improved. The thickness of the high-density polyethylene layer is preferably the same as or greater than the thickness of the low-density polyethylene layer. The ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer is preferably 1 / 0.25 or more and 1 / 2 or less, and more preferably 1 / 0.5 or more and 1 / 1 or less. By setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer to 1 / 0.25 or more, the heat resistance of the substrate can be improved. Also, by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer to 1 / 1 or less, the adhesion between the medium-density polyethylene layers can be improved. The thickness of each high-density polyethylene layer is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 10 μm or less. By making the thickness of the high-density polyethylene layer 1 μm or more, the strength and heat resistance of the laminate of the present invention can be further improved. Furthermore, by making the thickness of the high-density polyethylene layer 20 μm or less, the processability of the laminate of the present invention can be further improved. The thickness of the medium-density polyethylene layer is preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. By making the thickness of the medium-density polyethylene layer 1 μm or more, the stretchability of the film can be further improved. Furthermore, by making the thickness of the medium-density polyethylene layer 30 μm or less, the processability of the laminate of the present invention can be further improved. The thickness of the low-density polyethylene layer is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 5 μm or less. By making the thickness of the low-density polyethylene layer 1 μm or more, the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer can be further improved. Furthermore, by making the thickness of the low-density polyethylene layer 5 μm or less, the processability of the laminate of the present invention can be further improved. In one embodiment, a substrate having such a configuration can be produced by, for example, an inflation method. Specifically, the film can be produced by co-extruding a high-density polyethylene layer, a medium-density polyethylene layer, and a low-density polyethylene layer, a linear low-density polyethylene layer, or an ultra-low-density polyethylene layer from the outside into a tubular shape, and then pressing the opposing low-density polyethylene layers, linear low-density polyethylene layers, or ultra-low-density polyethylene layers together using a rubber roll or the like. By using such a method, the number of defective products in the manufacturing process can be significantly reduced, and ultimately production efficiency can be improved. Furthermore, stretching can also be carried out in the inflation film-forming machine, which can further improve production efficiency.

[0032] In one embodiment, the film may be configured as a seven-layer co-extruded film consisting of, from the outside, a high-density polyethylene layer, a blend resin layer of high-density polyethylene and medium-density polyethylene, a medium-density polyethylene layer, a low-density polyethylene layer, a linear low-density polyethylene layer or an ultra-low-density polyethylene layer (in this paragraph, for simplicity, these are collectively referred to as low-density polyethylene layers), a medium-density polyethylene layer, a blend resin layer of high-density polyethylene and medium-density polyethylene, and a high-density polyethylene layer. This structure can improve the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer, and can also improve the processability of the laminate of the present invention. The thickness of each high-density polyethylene layer is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 10 μm or less. By making the thickness of the high-density polyethylene layer 1 μm or more, the strength and heat resistance of the laminate of the present invention can be further improved. Furthermore, by making the thickness of the high-density polyethylene layer 20 μm or less, the processability of the laminate of the present invention can be further improved. The thickness of each blend resin layer of high-density polyethylene and medium-density polyethylene is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 10 μm or less. This improves adhesion between the high-density polyethylene layer and the medium-density polyethylene layer. It also improves the processability of the laminate of the present invention. The thickness of the medium-density polyethylene layer is preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. By making the thickness of the medium-density polyethylene layer 1 μm or more, the stretchability of the film can be further improved. Furthermore, by making the thickness of the medium-density polyethylene layer 30 μm or less, the processability of the laminate of the present invention can be further improved. The thickness of the low-density polyethylene layer is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 5 μm or less. By making the thickness of the low-density polyethylene layer 1 μm or more, the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer can be further improved, and by making the thickness of the low-density polyethylene layer 5 μm or less, the processability of the laminate of the present invention can be further improved. In one embodiment, the stretched polyethylene film having such a configuration can be produced by the inflation method described above. By using such a method, the number of defective products in the manufacturing process can be significantly reduced, and ultimately production efficiency can be improved. Furthermore, stretching can also be carried out in the inflation film-forming machine, which can further improve production efficiency.

[0033] When the substrate is subjected to a stretching treatment, the stretching may be uniaxial or biaxial. The stretching ratio in the machine direction (MD) of the substrate is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less. By stretching the substrate in the machine direction (MD) at a ratio of 2 or more, the strength and heat resistance of the substrate can be improved. Furthermore, the printability of the substrate can be improved. Furthermore, the transparency of the substrate can be improved. On the other hand, the upper limit of the stretching ratio in the machine direction (MD) of the substrate is not particularly limited, but from the viewpoint of the breaking limit of the substrate, it is preferably 10 times or less. The stretching ratio in the transverse direction (TD) of the substrate is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less. By setting the stretching ratio in the transverse direction (TD) of the substrate to 2 times or more, the strength and heat resistance of the substrate can be improved. Furthermore, the printability of the substrate can be improved. Furthermore, the transparency of the substrate can be improved. On the other hand, the upper limit of the stretching ratio in the transverse direction (TD) of the substrate is not particularly limited, but from the viewpoint of the breaking limit of the substrate, it is preferably 10 times or less.

[0034] When the substrate is irradiated with an electron beam, the crosslink density of the polyethylene or polypropylene contained in the substrate is increased by the electron beam irradiation, and the heat resistance and strength of the substrate can be significantly improved. This embodiment is particularly suitable when the substrate is made of polyethylene.

[0035] The substrate may be one in which the polyethylene on one side has been irradiated with an electron beam to increase the crosslink density, or the substrate may be one in which the crosslink density of the polyolefin throughout the substrate has been increased. When the substrate has a multi-layer structure, it is sufficient that the crosslink density of the polyethylene in the outermost layer is improved by electron beam irradiation. From the viewpoint of strength and heat resistance, it is preferable that the crosslink density of the polyethylene as a whole is improved by electron beam irradiation.

[0036] The device that can be used to irradiate the substrate with an electron beam can be a conventionally known device, such as a curtain-type electron beam irradiation device (LB1023, manufactured by i-Electron Beam Co., Ltd.), a line-type low-energy electron beam irradiation device (EB-ENGINE, manufactured by Hamamatsu Photonics K.K.), and a drum-roll-type electron beam irradiation device (EZ-CURE, manufactured by i-Electron Beam Co., Ltd.).

[0037] The dose of the electron beam irradiated onto the substrate is preferably in the range of 10 kGy to 2000 kGy, more preferably in the range of 20 kGy to 1000 kGy, and even more preferably in the range of 150 kGy to 500 kGy. The acceleration voltage of the electron beam is preferably in the range of 30 kV to 300 kV, more preferably in the range of 50 kV to 300 kV, and even more preferably in the range of 50 kV to 250 kV. Furthermore, the irradiation energy of the electron beam is preferably in the range of 20 keV or more and 750 keV or less, more preferably in the range of 25 keV or more and 500 keV or less, even more preferably in the range of 30 keV or more and 400 keV or less, and particularly preferably in the range of 20 keV or more and 200 keV or less.

[0038] The oxygen concentration in the electron beam irradiation apparatus is preferably 500 ppm or less, more preferably 100 ppm or less. By performing electron beam irradiation under such conditions, it is possible to suppress the generation of ozone and also to prevent the radicals generated by electron beam irradiation from being deactivated by oxygen in the atmosphere. Such conditions can be achieved, for example, by creating an inert gas (nitrogen, argon, etc.) atmosphere inside the apparatus.

[0039] In one embodiment, the electron beam irradiation can be performed simultaneously with cooling using a cooling drum or the like.

[0040] 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.

[0041] 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.

[0042] The thickness of the substrate is preferably 10 μm or more and 50 μm or less, and more preferably 15 μm or more and 30 μm or less. By making the thickness of the substrate 10 μm or more, the strength and heat resistance of the substrate can be further improved. Furthermore, by making the thickness of the substrate 50 μm or less, the processability of a laminate including the substrate can be improved.

[0043] The substrate can be produced by forming a resin composition containing at least polyethylene or polypropylene into a film using a T-die method, an inflation method, or the like, to form a resin film, and then stretching and / or irradiating it with an electron beam. By forming the film by the inflation method, the resin film can be stretched at the same time. When the resin film is stretched and irradiated with electron beams at the same time, either of them may be performed first, but it is preferable to perform the stretching first from the viewpoint of suitability for stretching processing.

[0044] When the substrate is produced by the T-die method, the MFR of the resin composition is preferably 3 g / 10 min or more and 20 g / 10 min or less. By setting the MFR of the resin composition to 3 g / 10 min or more, the processability of the substrate can be improved, and by setting the MFR of the resin composition to 20 g / 10 min or less, the substrate can be prevented from breaking during stretching.

[0045] When the substrate is produced by an inflation method, the MFR of the resin composition is preferably 0.5 g / 10 min or more and 5 g / 10 min or less. By setting the MFR of the resin composition to 0.5 g / 10 min or more, the processability of the substrate can be improved, and by setting the MFR of the resin composition to 5 g / 10 min or less, the film-forming properties can be improved.

[0046] (sealant layer) In one embodiment, the sealant layer is made of the same material as the substrate, i.e., polyethylene or polypropylene, which can improve the recyclability of the laminate.

[0047] From the viewpoint of heat sealability, the sealant layer preferably contains polyethylene, and more preferably contains low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene. In order to improve the tearability of a packaging bag produced using the laminate of the present invention, the sealant layer preferably contains low-density polyethylene. Furthermore, in order to improve the drop strength of a packaging bag produced using the laminate of the present invention, the sealant layer preferably contains a linear low-density polyethylene. Examples of linear low-density polyethylene include C-4 LLDPE and C-6 LLDPE. From the viewpoint of a balance between tearability and impact strength, C-4 LLDPE is preferred, and from the viewpoint of improving drop strength, C-6 LLDPE is preferred. Preferably, the sealant layer comprises both C-4 LLDPE and C-6 LLDPE.

[0048] When the sealant layer contains low-density polyethylene and linear low-density polyethylene, the content of low-density polyethylene is preferably 5% by mass or more and 20% by mass or less, and more preferably 9% by mass or more and 15% by mass or less. By setting the content of low-density polyethylene to 5% by mass or more, the tearability of the packaging bag produced using the laminate of the present invention can be further improved. By setting the content of low-density polyethylene to 20% by mass or less, the drop strength of the packaging bag produced using the laminate of the present invention can be maintained. The content of linear low-density polyethylene is preferably 65% ​​by mass or more and 90% by mass or less, and more preferably 70% by mass or more and 80% by mass or less. By setting the content of linear low-density polyethylene to 65% by mass or more, the drop strength of packaging bags produced using the laminate of the present invention can be further improved. By setting the content of linear low-density polyethylene to 90% by mass or less, additives such as slip agents and anti-blocking agents can be added, and a high-quality film with excellent processability can be obtained.

[0049] The sealant layer may also include the biomass-derived polyethylene, mechanically recycled polyethylene, polypropylene, and the like.

[0050] The sealant layer may contain the above-mentioned additives as long as the properties of the present invention are not impaired.

[0051] In one embodiment, the sealant layer includes a light-shielding layer containing a light-shielding pigment together with polyethylene or polypropylene. This can improve the storage stability of the contents filled in the packaging bag made from the laminate of the present invention. The light-shielding layer may have a single-layer structure or a multi-layer structure.

[0052] Examples of light-shielding pigments include carbon black, acetylene black, lamp black, black smoke, iron black, aniline black, titanium oxide, barium oxide, calcium carbonate, aluminum hydroxide, and zinc oxide. By using these light-shielding pigments, the contents filled in the packaging bag made from the laminate of the present invention can be concealed. Furthermore, by using a white pigment such as titanium oxide, the sealant layer can be given the function of a background layer, thereby improving the visibility of the image formed on the substrate.

[0053] The content of the light-shielding pigment in the light-shielding layer is preferably from 2 to 25% by mass, more preferably from 4 to 23% by mass, which can further improve the storage stability of the contents filled in the packaging bag made from the laminate of the present invention while maintaining the heat sealability of the heat seal layer.

[0054] The thickness of the light-shielding layer is preferably 10 μm or more and 60 μm or less, and more preferably 15 μm or more and 40 μm or less, which can further improve the storage stability of the contents filled in the packaging bag made from the laminate of the present invention.

[0055] The sealant layer may have a single-layer structure or a multi-layer structure, for example, composed of a laminating layer to be laminated to the substrate, an intermediate layer, and a heat-sealing layer. When the sealant layer includes a light-shielding layer, it is preferably provided as an intermediate layer, which can improve the light-shielding properties without impairing the heat-sealing properties and lamination properties with the substrate.

[0056] In one embodiment, the intermediate layer of the multi-layer sealant layer contains at least one of medium density polyethylene and high density polyethylene, which can further improve the strength of the laminate of the present invention. Specific examples of intermediate layers containing at least one of medium-density polyethylene and high-density polyethylene include a configuration including a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very-low-density polyethylene, a layer containing at least one of medium-density polyethylene and high-density polyethylene, and a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very-low-density polyethylene. By adopting the above-mentioned configuration, the bag-making suitability and strength of the laminate of the present invention can be further improved while maintaining heat sealability.

[0057] The thickness of the sealant layer is preferably 40 μm or more and 150 μm or less, and more preferably 60 μm or more and 100 μm or less, which can further improve the heat sealability of the laminate of the present invention.

[0058] (barrier coat layer) The laminate of the present invention is characterized by including a barrier coat layer between the substrate and the sealant layer, which can improve the oxygen barrier property and water vapor barrier property of the laminate.

[0059] 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. When the laminate of the present invention includes a vapor-deposited film made of an inorganic oxide, by providing a barrier coat layer of this type adjacent to the vapor-deposited film, it is possible to effectively prevent cracks from occurring in the vapor-deposited film.

[0060] 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.

[0061] 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.

[0062] 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).

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The thickness of the gas barrier coating film is preferably from 0.01 μm to 100 μm, and more preferably from 0.1 μm to 50 μm, which allows for improved oxygen barrier properties and water vapor barrier properties while maintaining recyclability. 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 can be improved, and when the gas barrier coating film is provided adjacent to a vapor-deposited film made of an inorganic oxide, the occurrence of cracks in the vapor-deposited film can be prevented.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] The composition may also contain an organic solvent, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, or n-butanol.

[0072] 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.

[0073] The barrier coat layer may have a printed layer formed thereon, and the method for forming the printed layer is as described above.

[0074] The barrier coat layer may contain the above-mentioned additives to the extent that the properties of the present invention are not impaired.

[0075] (evaporated film) In one embodiment, the laminate of the present invention may have a vapor-deposited film between the substrate and the barrier coat layer or between the barrier coat layer and the sealant layer. This can improve the gas barrier properties of the laminate, specifically the oxygen barrier properties and water vapor barrier properties. Furthermore, it can also suppress the weight loss of the contents packed in a packaging bag made using the laminate of the present invention.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The surface of the deposited film is preferably subjected to the above-mentioned surface treatment, which can improve adhesion to adjacent layers.

[0081] (Light-shielding printing layer) In one embodiment, the laminate of the present invention includes a light-blocking printed layer between the barrier coat layer and the sealant layer, which can improve the storage stability of the contents filled in the packaging bag made from the laminate of the present invention.

[0082] The light-shielding printed layer contains a light-shielding ink, and although the color is not particularly limited, it is preferable to change the color appropriately depending on the contents, such as black, white, gray, orange, red, yellow, silver, and brown. If the contents contain vitamins, they are susceptible to deterioration by light with wavelengths of 500 nm or less, so it is preferable to use ink in a color that absorbs light with this wavelength, such as orange. Furthermore, aluminum-containing ink or ultraviolet-curable ink can also be used as the light-shielding ink. The white light-shielding ink layer functions as a background layer and can improve the visibility of the image formed on the substrate.

[0083] Examples of light-shielding pigments that can be contained in the light-shielding ink include, but are not limited to, carbon black, acetylene black, lamp black, black smoke, iron black, aniline black, titanium oxide, and zinc oxide.

[0084] The light-shielding printing layer may have a multi-layer structure, for example, a configuration comprising a white ink layer and a gray ink layer, a configuration comprising a white ink layer and a black ink layer, a configuration comprising a white ink layer, a yellow ink layer and a red ink layer, or a configuration comprising a white ink layer and a silver ink layer.

[0085] The thickness of the light-shielding printed layer is preferably 0.2 μm or more and 8 μm or less, and more preferably 0.5 μm or more and 6 μm or less. By making the thickness of the light-shielding printed layer 0.2 μm or more, the storage stability of the contents filled in the packaging bag made from the laminate of the present invention can be further improved. By making the thickness of the light-shielding printed layer 5 μm or less, a laminate with stable physical properties can be obtained without impairing the adhesion with the sealant layer.

[0086] The method for forming the light-shielding printed layer is not particularly limited, and examples thereof include conventionally known printing methods such as offset printing, flexographic printing, etc. Among these, flexographic printing is preferred from the viewpoint of environmental load.

[0087] (adhesive layer) 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.

[0088] Furthermore, when the laminate of the present invention includes an aluminum vapor-deposited film, the adhesive layer provided adjacent to the aluminum vapor-deposited film preferably comprises a cured product of a resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound. When a laminate with a vapor-deposited film is formed into a packaging bag, a bending load is applied to the laminate by a molding machine or the like, which may cause cracks in the aluminum vapor-deposited film. By configuring the adhesive layer as described above, it is possible to prevent cracks from occurring in the aluminum vapor-deposited film, and even if cracks do occur, it is possible to suppress a decrease in the oxygen barrier property and water vapor barrier property (flexural load resistance).

[0089] The polyester polyol has two or more hydroxyl groups as functional groups in one molecule. The isocyanate compound has two or more isocyanate groups as functional groups in one molecule. The polyester polyol has, for example, a polyester structure or a polyester polyurethane structure as the main skeleton.

[0090] As a specific example of a resin composition (adhesive) containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound, the PASLIM series available from DIC Corporation can be used.

[0091] The resin composition may further contain a plate-like inorganic compound, a coupling agent, cyclodextrin and / or a derivative thereof, and the like.

[0092] As polyester polyols having two or more hydroxyl groups in one molecule as functional groups, for example, the following [Example 1] to [Example 3] can be used. [Example 1] Polyester polyol obtained by polycondensation of ortho-oriented polycarboxylic acid or its anhydride with polyhydric alcohol [Example 2] Polyester polyol with a glycerol skeleton [Example 3] Polyester polyol with isocyanuric ring Each polyester polyol will be described below.

[0093] The polyester polyol according to the first example is a polycondensate obtained by polycondensing a polycarboxylic acid component containing at least one or more of orthophthalic acid and its anhydride, and a polyhydric alcohol component containing at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol. In particular, polyester polyols in which the content of orthophthalic acid and its anhydride relative to the total polycarboxylic acid components is 70 to 100 mass % are preferred.

[0094] The polyester polyol according to the first example essentially contains orthophthalic acid and its anhydride as polycarboxylic acid components, but other polycarboxylic acid components may be copolymerized within a range that does not impair the effects of this embodiment. Specific examples include aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid; unsaturated bond-containing polycarboxylic acids such as maleic anhydride, maleic acid, and fumaric acid; alicyclic polycarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, anhydrides of these dicarboxylic acids, and ester-forming derivatives of these dicarboxylic acids; and polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids. Among these, succinic acid, 1,3-cyclopentanedicarboxylic acid, and isophthalic acid are preferred. Two or more of the above other polycarboxylic acids may be used.

[0095] As a polyester polyol according to a second example, a polyester polyol having a glycerol skeleton represented by general formula (1) can be mentioned. [ka] In general formula (1), R1, R2, and R3 are each independently H (hydrogen atom) or a group represented by the following general formula (2). [ka]

[0096] In formula (2), n represents an integer of 1 to 5, X represents an arylene group selected from the group consisting of 1,2-phenylene groups, 1,2-naphthylene groups, 2,3-naphthylene groups, 2,3-anthraquinonediyl groups, and 2,3-anthracenediyl groups, which may have a substituent, and Y represents an alkylene group having 2 to 6 carbon atoms. However, at least one of R1, R2, and R3 represents a group represented by general formula (2).

[0097] In general formula (1), at least one of R1, R2, and R3 must be a group represented by general formula (2). In particular, it is preferable that all of R1, R2, and R3 are groups represented by general formula (2).

[0098] In addition, the compound may be a mixture of two or more of the following compounds: a compound in which any one of R1, R2, and R3 is a group represented by general formula (2); a compound in which any two of R1, R2, and R3 are groups represented by general formula (2); and a compound in which all of R1, R2, and R3 are groups represented by general formula (2).

[0099] X represents an optionally substituted arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group. When X is substituted with a substituent, it may be substituted with one or more substituents, and the substituent is bonded to any carbon atom on X that is different from the free radical. The substituent includes a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

[0100] In general formula (2), Y represents an alkylene group having 2 to 6 carbon atoms, such as an ethylene group, a propylene group, a butylene group, a neopentylene group, a 1,5-pentylene group, a 3-methyl-1,5-pentylene group, a 1,6-hexylene group, a methylpentylene group, or a dimethylbutylene group. Of these, a propylene group or an ethylene group is preferred, and an ethylene group is most preferred.

[0101] The polyester resin compound having a glycerol skeleton represented by general formula (1) can be synthesized by reacting glycerol, an aromatic polycarboxylic acid or its anhydride in which a carboxylic acid is substituted at the ortho position, and a polyhydric alcohol component as essential components.

[0102] Examples of aromatic polycarboxylic acids or anhydrides in which a carboxylic acid is substituted at the ortho position include orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracenecarboxylic acid or anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring, such as a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, or a naphthyl group.

[0103] Examples of polyhydric alcohol components include alkylene diols having 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, and dimethylbutanediol.

[0104] The polyester polyol according to the third example is a polyester polyol having an isocyanuric ring represented by the following general formula (3). [ka] In the general formula (3), R1, R2, and R3 each independently represent "-(CH2)n1-OH (wherein n1 represents an integer of 2 to 4)" or a structure of the general formula (4). [ka]

[0105] In general formula (4), n2 represents an integer of 2 to 4, n3 represents an integer of 1 to 5, X represents an arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group, which may have a substituent, and Y represents an alkylene group having 2 to 6 carbon atoms. However, at least one of R1, R2, and R3 is a group represented by general formula (4).

[0106] In the general formula (3), the alkylene group represented by -(CH2)n1- may be linear or branched. Among these, n1 is preferably 2 or 3, and most preferably 2.

[0107] In the general formula (4), n2 represents an integer of 2 to 4, and n3 represents an integer of 1 to 5. X represents an arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group, which may have a substituent.

[0108] When X is substituted with a substituent, it may be substituted with one or more substituents, and the substituent is bonded to any carbon atom on X that is different from the free radical. The substituent includes a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group. The substituent for X is preferably a hydroxyl group, a cyano group, a nitro group, an amino group, a phthalimido group, a carbamoyl group, an N-ethylcarbamoyl group, or a phenyl group, and most preferably a hydroxyl group, a phenoxy group, a cyano group, a nitro group, a phthalimido group, or a phenyl group.

[0109] In general formula (4), Y represents an alkylene group having 2 to 6 carbon atoms, such as an ethylene group, a propylene group, a butylene group, a neopentylene group, a 1,5-pentylene group, a 3-methyl-1,5-pentylene group, a 1,6-hexylene group, a methylpentylene group, or a dimethylbutylene group. Of these, a propylene group or an ethylene group is preferred, and an ethylene group is most preferred.

[0110] In general formula (3), at least one of R1, R2, and R3 is a group represented by general formula (4). In particular, it is preferable that all of R1, R2, and R3 are groups represented by general formula (4).

[0111] In addition, the compound may be a mixture of two or more of the following compounds: a compound in which any one of R1, R2, and R3 is a group represented by general formula (4); a compound in which any two of R1, R2, and R3 are groups represented by general formula (4); and a compound in which all of R1, R2, and R3 are groups represented by general formula (4).

[0112] The polyester polyol having an isocyanuric ring represented by general formula (3) can be synthesized by reacting a triol having an isocyanuric ring, an aromatic polycarboxylic acid or its anhydride in which a carboxylic acid is substituted at the ortho position, and a polyhydric alcohol component as essential components.

[0113] Examples of triols having an isocyanuric ring include alkylene oxide adducts of isocyanuric acid such as 1,3,5-tris(2-hydroxyethyl)isocyanuric acid and 1,3,5-tris(2-hydroxypropyl)isocyanuric acid.

[0114] Examples of aromatic polycarboxylic acids or anhydrides in which a carboxylic acid is substituted at the ortho position include orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracene carboxylic acid or anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring.

[0115] Examples of the substituent include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

[0116] The polyhydric alcohol component may be an alkylene diol having 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, or dimethylbutanediol. Among these, polyester polyol compounds having an isocyanuric ring, which use 1,3,5-tris(2-hydroxyethyl)isocyanuric acid or 1,3,5-tris(2-hydroxypropyl)isocyanuric acid as the triol compound having an isocyanuric ring, orthophthalic anhydride as the aromatic polycarboxylic acid or its anhydride in which the carboxylic acid is substituted at the ortho position, and ethylene glycol as the polyhydric alcohol, are particularly preferred because of their excellent oxygen barrier properties and adhesiveness.

[0117] The isocyanuric ring is highly polar and trifunctional, and can increase the polarity of the entire system and the crosslink density. From these perspectives, it is preferable that the adhesive resin contains 5% by mass or more of the isocyanuric ring based on the total solid content of the adhesive resin.

[0118] The isocyanate compound has two or more isocyanate groups in the molecule. The isocyanate compound may be either aromatic or aliphatic, and may be either a low molecular weight compound or a high molecular weight compound. Furthermore, the isocyanate compound may be a blocked isocyanate compound obtained by addition reaction using a known isocyanate blocking agent by a known, conventional appropriate method. Among these, from the viewpoints of adhesiveness and retort resistance, polyisocyanate compounds having three or more isocyanate groups are preferred, and from the viewpoints of oxygen barrier property and water vapor barrier property, aromatic compounds are preferred.

[0119] Specific examples of the isocyanate compound include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, metaxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds, as well as adducts, biurets, and allophanates obtained by reacting these isocyanate compounds with low-molecular-weight active hydrogen compounds or alkylene oxide adducts thereof, or high-molecular-weight active hydrogen compounds. Examples of low molecular weight active hydrogen compounds include ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, and metaxylylenediamine. Examples of high molecular weight active hydrogen compounds include polymeric active hydrogen compounds of various polyester resins, polyether polyols, and polyamides.

[0120] The phosphoric acid-modified compound is, for example, a compound represented by the following general formula (5) or (6). [ka] In general formula (5), R1, R2, and R3 are groups selected from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a (meth)acryloyl group, a phenyl group which may have a substituent, and an alkyl group having 1 to 4 carbon atoms which has a (meth)acryloyloxy group, at least one of which is a hydrogen atom, and n is an integer of 1 to 4. [ka] In the formula, R4 and R5 are groups selected from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a (meth)acryloyl group, a phenyl group which may have a substituent, and an alkyl group having 1 to 4 carbon atoms and having a (meth)acryloyloxy group, n is an integer of 1 to 4, x is an integer of 0 to 30, and y is an integer of 0 to 30, except when both x and y are 0.

[0121] More specific examples include phosphoric acid, pyrophosphoric acid, triphosphoric acid, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, dibutyl phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, isododecyl acid phosphate, butoxyethyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, and polyoxyethylene alkyl ether phosphate, and one or more of these can be used.

[0122] The content of the phosphoric acid-modified compound in the resin composition is preferably 0.005% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 1% by mass or less. By adjusting the content of the phosphate-modified compound to 0.005% by mass or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be improved, and by adjusting the content of the phosphate-modified compound to 10% by mass or less, the adhesiveness of the adhesive layer can be improved.

[0123] The resin composition containing a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound may contain a plate-like inorganic compound, which can improve the adhesiveness of the adhesive layer and the flex load resistance of the laminate of the present invention. Examples of the plate-like inorganic compounds include kaolinite-serpentine group clay minerals (halloysite, kaolinite, endelite, dickite, nacrite, antigorite, chrysotile, etc.) and pyrophyllite-talc group (pyrophyllite, talc, keroli, etc.).

[0124] Examples of coupling agents include silane-based coupling agents, titanium-based coupling agents, and aluminum-based coupling agents represented by the following general formula (7). These coupling agents may be used alone or in combination of two or more. [ka]

[0125] Examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxytrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β( N-beta(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-beta(aminoethyl)γ-aminopropyltrimethoxysilane, N-beta(aminoethyl)γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-triethoxysilyl-N-(1,3-dimethylbutylidene).

[0126] Examples of titanium-based coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraoctyl bis(didodecyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctainol titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, diisostearoyl ethylene titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and dicumyl phenyl oxyacetate titanate.

[0127] Specific examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate, diisopropoxyaluminum ethyl acetoacetate, diisopropoxyaluminum monomethacrylate, isopropoxyaluminum alkyl acetoacetate mono(dioctyl phosphate), aluminum-2-ethylhexanoate oxide trimer, aluminum stearate oxide trimer, and alkyl acetoacetate aluminum oxide trimer.

[0128] The resin composition may contain cyclodextrin and / or a derivative thereof, which can improve the adhesiveness of the adhesive layer and further improve the flex load resistance of the laminate of the present invention. Specifically, for example, cyclodextrin, alkylated cyclodextrin, acetylated cyclodextrin, hydroxyalkylated cyclodextrin, and the like, in which the hydrogen atoms of the hydroxyl groups of the glucose units of cyclodextrin are substituted with other functional groups, can be used. Branched cyclic dextrins can also be used. Furthermore, the cyclodextrin skeleton in cyclodextrin and cyclodextrin derivatives may be any of α-cyclodextrin consisting of six glucose units, β-cyclodextrin consisting of seven glucose units, and γ-cyclodextrin consisting of eight glucose units. These compounds may be used alone or in combination of two or more. These cyclodextrins and / or their derivatives may hereinafter be collectively referred to as dextrin compounds.

[0129] From the viewpoint of compatibility and dispersibility in the resin composition, it is preferable to use a cyclodextrin derivative as the cyclodextrin compound.

[0130] Examples of alkylated cyclodextrins include methyl-α-cyclodextrin, methyl-β-cyclodextrin, and methyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

[0131] Examples of acetylated cyclodextrins include monoacetyl-α-cyclodextrin, monoacetyl-β-cyclodextrin, and monoacetyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

[0132] Examples of hydroxyalkylated cyclodextrins include hydroxypropyl-α-cyclodextrin, hydroxypropyl-β-cyclodextrin, and hydroxypropyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

[0133] The adhesive layer may contain additives such as pigments such as titanium oxide, 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.

[0134] The thickness of the adhesive layer is not particularly limited, and can be, for example, 1 μm or more and 10 μm or less.

[0135] (middle class) In one embodiment, the laminate of the present invention comprises a polyethylene or polypropylene layer as the intermediate layer.

[0136] The polyethylene layer or polypropylene layer may be composed of a stretched film, and may be a uniaxially stretched film or a biaxially stretched film, and the preferred stretching ratio is as described above. The polyethylene layer or polypropylene layer may be an extruded resin layer formed by melt-extruding polyethylene or polypropylene.

[0137] The thickness of the polyethylene layer or polypropylene layer is preferably 10 μm or more and 70 μm or less, and more preferably 15 μm or more and 50 μm or less.

[0138] In one embodiment, the laminate of the present invention includes a gas barrier layer made of a gas barrier resin as an intermediate layer. By providing the laminate of the present invention with such an intermediate layer, the oxygen barrier property and water vapor barrier property can be improved. Examples of gas barrier resins include ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, polyamides such as nylon 6, nylon 6,6 and polymetaxylylene adipamide (MXD6), polyesters, polyurethanes, and (meth)acrylic resins.

[0139] The thickness of the gas barrier layer is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less. By making the thickness of the gas barrier layer 0.01 μm or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be further improved, and by making the thickness of the gas barrier layer 10 μm or less, the recyclability of the laminate of the present invention can be maintained.

[0140] In one embodiment, the intermediate layer comprises a vapor-deposited film. The form, preferred thickness, and formation method of the vapor-deposited film that can be used are as described above.

[0141] In one embodiment, the intermediate layer comprises a barrier coating layer, the configuration, preferred thickness, forming method, etc. of which are as described above.

[0142] (packaging bag) The packaging bag of the present invention is characterized by being made from the above laminate. The shape of the packaging bag is not particularly limited, and may be a stand-up pouch having a bag-like shape as shown in FIG.

[0143] In one embodiment, the packaging bag 20 of the present invention may be a stand-up pouch equipped with a pouring nozzle part 21 as shown in FIG. 5 when the content is a liquid, a viscous material, or a powder. From the viewpoint of ease of opening, the packaging bag 20 may have a curved portion 22 that curves inward, as shown in FIG. Furthermore, a cutout 23 may be provided, which may be formed by a laser beam or the like.

[0144] In one embodiment, the packaging bag 30 of the present invention may be a stand-up pouch having a spout 32 attached by an upper edge seal portion 31, as shown in Fig. 6. A lid stopper 33 is screwed onto the upper end of the spout 32. The material of this spout is not particularly limited, but it is preferable that it be made of polyethylene when the base material and sealant layer are made of polyethylene, and that it be made of polypropylene when the base material and sealant layer are made of polypropylene.

[0145] In addition, the hatched areas represent heat-sealed areas in Figures 4 to 6. Furthermore, in Figures 3 to 5, stand-up pouches are shown as examples of packaging bags, but the present invention is not limited to this.

[0146] In one embodiment, the packaging bag can be produced by folding the laminate of the present invention in half, overlapping the laminate with the sealant layer on the inside, and heat-sealing the edges. In another embodiment, the packaging bag can also be produced by overlapping two laminates with the sealant layers facing each other, and heat-sealing the edges.

[0147] In one embodiment, the packaging bag can be produced by stacking two of the above laminates with the sealant layers facing each other and heat-sealing two sides to form a body, and then folding another laminate into a V shape with the sealant layer facing outward, sandwiching it from one end of the body, and heat-sealing it to form a bottom.

[0148] In one embodiment, the packaging bag can be produced by stacking two of the above-mentioned laminates with the sealant layers facing each other and heat-sealing one side to form a bottom, and then folding two more laminates into a V shape with the sealant layers facing outward, sandwiching the two laminates together from both ends, and heat-sealing to form a body.

[0149] The heat sealing method is not particularly limited, and can be performed by any known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, or ultrasonic sealing.

[0150] The contents to be filled into the packaging bag are not particularly limited, and may be liquid, powder, or gel. The contents may also be food or non-food. According to the packaging bag of the present invention, even if the contents are colored, such as detergent, they can be suitably filled because they do not affect the image formed on the substrate. [Example]

[0151] 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.

[0152] Example 1 As a substrate film, a 25 μm thick longitudinally uniaxially stretched polyethylene film (stretching ratio: approximately 5 times) was prepared.

[0153] A silica vapor deposition film having a thickness of 0.03 μm was formed on one surface of the substrate film by a CVD method.

[0154] 385 g of water, 67 g of isopropyl alcohol, and 9.1 g of 0.5 N hydrochloric acid were mixed. Solution A was prepared by mixing 175 g of tetraethoxysilane as a metal alkoxide and 9.2 g of glycidoxypropyltrimethoxysilane as a silane coupling agent into a solution adjusted to pH 2.2 while cooling to 10°C. Also, a solution B was prepared by mixing 14.7 g of polyvinyl alcohol having a degree of polymerization of 2400 and a saponification degree of 99% or more, 324 g of water, and 17 g of isopropyl alcohol as a water-soluble polymer. Next, solution A and solution B were mixed in a weight ratio of 6.5:3.5 to prepare a barrier coating agent, which was applied to the vapor-deposited film by spin coating and subjected to heat treatment to form a barrier coating layer. An image was formed on this barrier coat layer using a gravure printing machine.

[0155] On the barrier coating layer formed as described above, 3.0 g / m of a two-component curing polyester adhesive was applied. 2 Simultaneously with the application, an unstretched polyethylene film having a thickness of 80 μm was dry laminated to obtain a laminate of the present invention. The oxygen permeability of this laminate was measured in accordance with JIS K 7126 (constant pressure method) using OXTRAN 2 / 20 manufactured by MOCON, USA, under an environment of 23°C and relative humidity of 50%, and was found to be 1.42 cc / m 2 ·d·atm. The water vapor permeability of the laminate was measured in accordance with JIS K 7129 B method using a PERMATRAN 3 / 31 manufactured by MOCON, USA, under an environment of 40°C and a relative humidity of 90%, and was found to be 1.55 g / m 2 ·d.

[0156] The laminate was cut into a size of 100 mm wide x 150 mm long. The two laminates cut as described above were stacked together with the sealant layers facing each other, and then cut from both ends to a size of 100 mm wide x 50 mm long, folded into a V shape so that the sealant was on the outside, and sandwiched between the laminates. Next, one vertical side and the side sandwiching the V-shaped laminate were heat-sealed to obtain a packaging bag.

[0157] The jelly drink was filled through the opening of the packaging bag, and an injection-molded polyethylene spout was heat-sealed to tightly adhere the opening, and an injection-molded lid stopper was screwed onto the spout to obtain a stand-up pouch-shaped packaging bag. No leakage, tipping, buckling, etc. were observed in the packaging bag, and it was also subjected to a drop test from a height of 1.2 m five times, with no breakage or leakage observed.

[0158] Example 2 The laminate of the present invention was produced in the same manner as in Example 1, except that the substrate film was changed to a 25 μm thick biaxially oriented polypropylene film (stretching ratio: 3 to 6 times) and the sealant layer was changed to a 60 μm thick unstretched polypropylene film. The oxygen permeability and water vapor permeability of the laminate were measured in the same manner as in Example 1, and were found to be 1.27 cc / m 2 ·d·atm, 0.75g / m 2 ·d. Furthermore, a packaging bag was produced in the same manner as in Example 1. No leakage, tipping, buckling, or the like was observed in the packaging bag, and a drop test from 1.2 m was performed five times, with no breakage, leakage, or the like observed. The spout used was made of polypropylene.

[0159] Example 3 A biaxially stretched polypropylene film (stretching ratio: 3 to 6 times) having a thickness of 25 μm was prepared as a substrate film, and an image was formed on one side of the film using a gravure printing machine.

[0160] The above barrier coating agent was applied to the image-forming surface of the substrate film by spin coating, and then subjected to a heat treatment to form a barrier coating layer.

[0161] A silica vapor deposition film having a thickness of 0.03 μm was formed on the barrier coating layer by the CVD method.

[0162] A two-component curing polyester adhesive was applied at 3.0 g / m2 onto the silica vapor deposition film layer formed as described above, and an unstretched polypropylene film having a thickness of 60 μm was dry laminated thereon to obtain a laminate of the present invention.

[0163] Furthermore, a packaging bag was produced in the same manner as in Example 1. No leakage, tipping, buckling, or the like was observed in the packaging bag, and a drop test from 1.2 m was performed five times, with no breakage, leakage, or the like observed. The spout used was made of polypropylene.

[0164] Comparative Example 1 A laminate was produced in the same manner as in Example 1, except that the barrier coat layer was not provided. The oxygen permeability of the laminate was measured in the same manner as in Example 1, but the value was too high to measure. In addition, the water vapor permeability was measured and found to be 7.92 g / m 2 ·d. Furthermore, a packaging bag was produced in the same manner as in Example 1. No leakage, tipping, buckling, or the like was observed in the packaging bag, and a drop test from 1.2 m was performed five times, with no breakage, leakage, or the like observed.

[0165] Comparative Example 2 A laminate was produced in the same manner as in Example 1, except that the substrate film was changed to an unstretched polyethylene film having a thickness of 25 μm. The oxygen permeability of the laminate was measured in the same manner as in Example 1, but the value was too high to measure. In addition, the water vapor permeability was measured and found to be 4.13 g / m 2 ·d. Furthermore, similarly to Example 1, an attempt was made to produce a packaging bag, but the heat resistance of the base film was insufficient and heat sealing was not possible. [Explanation of symbols]

[0166] 10: laminate, 11: substrate, 12: sealant layer, 13: barrier coat layer, 14: light-shielding printed layer, 15: light-shielding layer, 16: laminate layer, 17: heat-seal layer, 20: packaging bag, 21: pouring nozzle, 22: curved portion, 23: cut-out portion, 30: packaging bag, 31: upper edge seal portion, 32: spout, 33: lid stopper

Claims

1. A laminate comprising a substrate and a sealant layer, the substrate and the sealant layer are made of the same material; the substrate has been subjected to at least one of a stretching treatment and an electron beam irradiation treatment, the same material is polyethylene or polypropylene, A laminate comprising a barrier coat between the substrate and the sealant layer.

2. 2. The laminate according to claim 1, wherein the barrier coat layer is a gas barrier coating film containing at least one of a hydrolyzate of a metal alkoxide or a hydrolysis condensate of a metal alkoxide obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer by a sol-gel method.

3. The laminate according to claim 1 or 2, wherein the barrier coat layer has a thickness of 0.01 μm or more and 100 μm or less.

4. The laminate according to any one of claims 1 to 3, further comprising a vapor-deposited film between the substrate and the barrier coat layer, or between the barrier coat layer and the sealant layer.

5. The laminate according to claim 4 , wherein the vapor-deposited film is composed of an inorganic oxide.

6. The laminate according to any one of claims 1 to 5, which is used for packaging bags.

7. A packaging bag comprising the laminate according to any one of claims 1 to 6.

8. The packaging bag according to claim 7, comprising a spout.

Images