Packaging film, packaging bag, and packaged product

Abstract

To provide a packaging film capable of suppressing the peeling and delamination of an ink layer even if retort treatment is performed, a packaging bag and a packaged product.SOLUTION: A packaging film comprising an ink layer, a substrate layer, an adhesive layer and a sealant layer in this order, wherein the ink layer is covered with a covering layer, the covering layer is obtained by using a resin composition for a covering layer containing a polyurethane resin and a curing agent, or a resin composition for a covering layer containing a polyamideimide resin, and the ink layer is obtained by using an ink containing a polyurethane resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to packaging films, packaging bags, and packaging products. [Background technology]

[0002] A packaging film generally comprises a base layer, an adhesive layer, and a sealant layer in this order. When an ink layer for displaying characters, pictures, etc. is provided on such a packaging film, the ink layer is generally provided on the sealant layer side (back side) of the base layer from the viewpoint of water resistance. For example, Patent Document 1 below discloses a packaging body made of a laminated film including a base layer, a printing layer (ink layer), and a sealant layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-182536 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the packaging material described in Patent Document 1 can prevent the ink layer from peeling even when subjected to retort treatment, there is room for improvement in terms of preventing delamination when performing retort treatment.

[0005] An object of the present disclosure is to provide a packaging film, a packaging bag, and a packaging product that can suppress peeling of an ink layer and also suppress delamination even when subjected to retort treatment. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present disclosure provides a packaging film comprising an ink layer, a substrate layer, an adhesive layer, and a sealant layer in this order, the ink layer being coated with a coating layer, the coating layer being obtained using a resin composition for a coating layer containing a polyurethane resin and a curing agent, or a resin composition for a coating layer containing a polyamideimide resin, and the ink layer being obtained using an ink containing a polyurethane resin. According to the packaging film, even when retort treatment is performed, peeling of the ink layer can be suppressed, and delamination can also be suppressed.

[0007] The inventors of the present disclosure speculate that the reason why the above effects are obtained is as follows. That is, when the resin composition for the coating layer contains a polyurethane resin or a polyamideimide resin, or when the ink contains a polyurethane resin, both the coating layer and the ink layer can have high hot water resistance. Furthermore, when the resin composition for the coating layer contains a polyurethane resin and a curing agent, or contains a polyamideimide resin, the coating layer can have high heat resistance. Therefore, even when the packaging film is retorted, the coating layer is less likely to deteriorate due to heat, and the ink layer is sufficiently protected from hot water by the coating layer, thereby suppressing deterioration of the ink layer. As a result, a decrease in adhesion of the ink layer to the substrate layer is suppressed, and peeling of the ink layer is suppressed. Furthermore, the inventors of the present disclosure speculate that if the ink layer and adhesive layer are in contact on the sealant layer side of the base layer, the heat generated during retort treatment will absorb components of the adhesive layer into the ink layer, reducing the cohesive strength of the ink layer and, as a result, making the packaging film more susceptible to delamination. In contrast, the packaging film of the present disclosure has an ink layer on the opposite side of the base layer from the sealant layer, and the ink layer and adhesive layer are separated, so that even when retort treatment is performed, a decrease in adhesion between the adhesive layer and the base layer is suppressed. Therefore, even when retort treatment is performed, delamination in the packaging film is suppressed. The inventors of the present disclosure speculate that the above-mentioned effects are achieved for the above reasons.

[0008] In the packaging film, it is preferable that the ink further contains a curing agent. In this case, when the ink layer is obtained using the ink, the curing agent promotes a crosslinking reaction (high molecular weight) of the polyurethane resin, increasing the molecular weight of the polyurethane resin. As a result, the cohesive strength of the ink layer itself can be increased, making the ink layer less susceptible to destruction. Furthermore, the crosslinking reaction (high molecular weight) of the polyurethane resin also improves the heat resistance of the ink layer itself. Therefore, even if the ink layer is exposed at the edge of the packaging film, deterioration of the exposed portion of the ink layer is suppressed after retorting the packaging film. As a result, peeling of the ink layer from the base layer can be further suppressed.

[0009] In the packaging film, the curing agent contained in the resin composition for the covering layer may include an isocyanate-based curing agent. In this case, the coating layer can effectively have high heat resistance. Therefore, even when the packaging film is retorted, the coating layer is less likely to deteriorate due to heat, and the ink layer is effectively protected from hot water by the coating layer, effectively suppressing deterioration of the ink layer. As a result, a decrease in adhesion of the ink layer to the base layer is effectively suppressed, and peeling of the ink layer is effectively suppressed.

[0010] In the packaging film, the curing agent contained in the ink preferably includes an isocyanate-based curing agent. In this case, the cohesive force of the ink layer can be effectively increased, and therefore, even if the ink layer is exposed at the end face of the packaging film, deterioration of the exposed portion of the ink layer is effectively suppressed after the packaging film is retorted, and peeling of the ink layer from the base layer can be more effectively suppressed.

[0011] The packaging film preferably further comprises a gas barrier layer between the adhesive layer and the base layer. In this case, the gas barrier properties of the packaging film are further improved.

[0012] In the packaging film, the base layer and the sealant layer may contain a polyolefin resin. In this case, since the base layer and the sealant layer contain a polyolefin resin, there is no need to separate the base layer and the sealant layer, and recycling can be easily carried out.

[0013] Another aspect of the present disclosure provides a packaging bag including the packaging film described above. The packaging bag includes the packaging film described above, and the packaging film can suppress peeling of the ink layer and delamination even when subjected to retort treatment. Therefore, the packaging bag can suppress peeling of the ink layer and delamination even when subjected to retort treatment.

[0014] Yet another aspect of the present disclosure provides a packaging product including the packaging bag described above and contents contained within the packaging bag. The packaging product includes the packaging bag described above, and the packaging bag can suppress peeling of the ink layer and delamination even when subjected to retort treatment. Therefore, the packaging product can suppress peeling of the ink layer and delamination even when subjected to retort treatment. This enables the packaging product to have a longer life. [Effects of the Invention]

[0015] According to the present disclosure, a packaging film, a packaging bag, and a packaging product are provided that can suppress peeling of the ink layer and also suppress delamination even when subjected to retort treatment. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view showing one embodiment of a packaging film of the present disclosure. [Figure 2] 1 is a cross-sectional view illustrating one embodiment of a packaging product of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail, but the present invention is not limited to the following embodiments.

[0018] <Packaging film> First, an embodiment of the packaging film of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing one embodiment of the packaging film of the present disclosure.

[0019] The packaging film 100 shown in FIG. 1 comprises an ink layer 20, a substrate 30, an adhesive layer 60, and a sealant layer 70 in this order, and the ink layer 20 is covered with a covering layer 10. The covering layer 10 is obtained using a resin composition for a covering layer containing a polyurethane resin and a curing agent, or a resin composition for a covering layer containing a polyamideimide resin. The ink layer 20 is obtained using an ink containing a polyurethane resin. The packaging film 100 may include an anchor coat layer 40 and a gas barrier layer 50 in this order from the base material layer 30 side between the base material layer 30 and the adhesive layer 60. The packaging film 100 may further include an intermediate layer (not shown) between the base material layer 30 and the adhesive layer 60. According to the packaging film 100, even when a retort treatment is performed, peeling of the ink layer 20 can be suppressed, and delamination can also be suppressed.

[0020] The coating layer 10, the ink layer 20, the substrate 30, the anchor coat layer 40, the gas barrier layer 50, the adhesive layer 60, the sealant layer 70 and the intermediate layer will be described in detail below.

[0021] (1) Covering layer The coating layer 10 is a layer that coats the ink layer 20. The coating layer 10 is provided on the ink layer 20 on the side opposite to the sealant layer 70. The coating layer 10 is obtained using a resin composition for a coating layer containing a polyurethane resin as a binder resin and a curing agent, or a polyamideimide resin. Examples of polyurethane resins include dispersions such as the Takelac W and WS series manufactured by Mitsui Chemicals, Inc., the ETERNACOLL series manufactured by Ube Industries, Ltd., the HYDRAN series manufactured by DIC Corporation, and the ADEKA BONTITAR HUX series manufactured by ADEKA Corporation, as well as solvent-based coating liquids such as the Takelac E series manufactured by Mitsui Chemicals, Inc. and the BURNOCK series manufactured by DIC Corporation. Examples of polyamide-imide resins include the Viromax series manufactured by Toyobo Co., Ltd.

[0022] The content of the polyurethane resin in the solid content contained in the resin composition for the covering layer is not particularly limited, and may be, for example, 50% by mass or more, 70% by mass or more, or 90% by mass or more. The content of the polyamideimide resin in the solid content contained in the resin composition for the coating layer is not particularly limited. The content of both the polyurethane resin and the polyamideimide resin in the solid content contained in the resin composition for the covering layer may be 99 mass % or less, taking into consideration the use of additives.

[0023] An isocyanate-based curing agent is preferred as the curing agent. In this case, the coating layer 10 can effectively have high heat resistance. Therefore, even when the packaging film 100 is retorted, the coating layer 10 is less likely to deteriorate due to heat, and the ink layer 20 is effectively protected from hot water by the coating layer 10, effectively suppressing deterioration of the ink layer 20. As a result, a decrease in adhesion of the ink layer 20 to the base layer 30 is effectively suppressed, and peeling of the ink layer 20 is effectively suppressed.

[0024] Examples of the isocyanate curing agent include hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), which may be used alone or in combination.

[0025] The content of the curing agent in the resin composition for the covering layer is not particularly limited, and may be, for example, 1% by mass or more, 3% by mass or more, or 5% by mass or more. The content of the curing agent in the resin composition for the covering layer may be 10% by mass or less.

[0026] The resin composition for the coating layer may further contain wax, in which case the adhesion of the coating layer 10 to the ink layer 20 is further improved. Examples of waxes include polyamide waxes and polyolefin waxes, which may be used alone or in combination.

[0027] The wax content in the solid content contained in the resin composition for the covering layer is not particularly limited, and may be, for example, 0 mass %, 1 mass % or more, 3 mass % or more, or 5 mass % or more. The wax content in the solid content contained in the resin composition for the covering layer may be 10% by mass or less.

[0028] The pigment content in the solid content contained in the resin composition for the coating layer is preferably smaller than the pigment content in the ink used to obtain the ink layer 20. In this case, the mechanical strength of the coating layer 10 is further improved. In addition, the transparency of the coating layer 10 is higher than that of the ink layer 20, and the visibility of the ink layer 20 is improved. Examples of pigments contained in the resin composition for the coating layer include inorganic pigments such as titanium oxide and iron oxide, and organic pigments such as isoindolinone, disazo, polyazo, diketopyrrolopyrrole, quinacridone, and phthalocyanine. These may be used alone or in combination.

[0029] The ratio R1 of the pigment content in the solid content contained in the resin composition for the coating layer to the pigment content in the solid content contained in the ink used to obtain the ink layer 20 may be, for example, less than 1, and may be 0.5 or less, 0.3 or less, or 0.1 or less. The ratio R1 may be 0 or greater.

[0030] The resin composition for the coating layer contains a solvent, such as ethyl acetate.

[0031] The resin composition for the coating layer may contain, as necessary, a plasticizer, a drying agent, a matting agent, a stabilizer, etc. Here, the matting agent is different from the pigment in the ink used to obtain the ink layer 20, and is a particle used to suppress the gloss of the coating layer 10.

[0032] The thickness of the coating layer 10 is not particularly limited and may be adjusted as needed, but is preferably 0.1 μm or more, more preferably 0.5 μm or more, and particularly preferably 1 μm or more from the viewpoint of improving the hot water resistance of the ink layer 20. Furthermore, from the viewpoint of recyclability, the thickness of the coating layer 10 is preferably 5 μm or less, more preferably 4 μm or less, and particularly preferably 3 μm or less.

[0033] Examples of methods for forming the coating layer 10 include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing.

[0034] (2) Ink layer The ink layer 20 is a layer that displays letters, pictures, symbols, and combinations thereof. The ink layer 20 is provided on the substrate layer 30 opposite the sealant layer 70, between the substrate layer 30 and the coating layer 10. By providing the ink layer 20 on the substrate layer 30 opposite the sealant layer 70, the ink layer 20 and the adhesive layer 60 are separated, and even when retort processing is performed, a decrease in adhesion between the adhesive layer 60 and the substrate layer 30 is suppressed. Therefore, even when retort processing is performed, delamination in the packaging film 100 is suppressed. Furthermore, even when the packaging film 100 is retort processed, the components of the adhesive layer 60 are no longer absorbed by the ink layer 20. Therefore, when obtaining the adhesive layer 60, it is not necessary to use more adhesive than necessary to account for the amount of the components of the adhesive layer 60 absorbed by the ink layer 20, thereby reducing the environmental impact. The ink layer 20 is obtained by using an ink containing a polyurethane resin as a binder resin.

[0035] The content of polyurethane resin in the solid content contained in the ink is not particularly limited, and may be, for example, 20% by mass or more, 30% by mass or more, or 40% by mass or more. The content of polyurethane resin in the solid content contained in the ink may be 80% by mass or less, 70% by mass or less, or 60% by mass or less.

[0036] The ink layer 20 may or may not further contain a curing agent, but preferably does. In this case, the curing agent promotes a crosslinking reaction (high molecular weight) of the polyurethane resin, increasing the molecular weight of the polyurethane resin. As a result, the cohesive force of the ink layer 20 itself can be increased, making the ink layer 20 less likely to be destroyed. The crosslinking reaction (high molecular weight) of the polyurethane resin also improves the heat resistance of the ink layer 20 itself. Therefore, even if the ink layer 20 is exposed at the end surface of the packaging film 100, deterioration of the exposed portion of the ink layer 20 is suppressed after retort processing of the packaging film 100. As a result, peeling of the ink layer 20 from the base layer 30 can be further suppressed. The curing agent is preferably an isocyanate-based curing agent, which can effectively increase the cohesive force of the ink layer 20. Therefore, even if the ink layer 20 is exposed at the end surface of the packaging film 100, deterioration of the exposed portion of the ink layer 20 is effectively suppressed after the retort treatment of the packaging film 100, and peeling of the ink layer 20 from the base layer 30 can be more effectively suppressed.

[0037] Examples of the isocyanate curing agent include hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), which may be used alone or in combination.

[0038] The content of the curing agent in the ink is not particularly limited, and may be, for example, 1% by mass or more, 3% by mass or more, or 5% by mass or more. The content of the curing agent in the ink may be 10% by mass or less, or 8% by mass or less.

[0039] The ink may further contain wax, which further improves the adhesion of the coating layer 10 to the ink layer 20. Examples of waxes include polyamide waxes and polyolefin waxes, which may be used alone or in combination.

[0040] The wax content in the solid content of the ink is not particularly limited, and may be, for example, 1% by mass or more, 3% by mass or more, or 5% by mass or more. The wax content in the solid content of the ink may be 10% by mass or less.

[0041] The ink contains a pigment. Examples of the pigment include inorganic pigments such as titanium oxide and iron oxide, and organic pigments such as isoindolinone, disazo, polyazo, diketopyrrolopyrrole, quinacridone, and phthalocyanine. These may be used alone or in combination. The content of the pigment in the solid content of the ink is not particularly limited, and may be, for example, 30% by mass or more, 40% by mass or more, or 50% by mass or more. The content of the pigment in the solid content of the ink may be 90% by mass or less.

[0042] The ink contains a solvent. The solvent may be an aqueous solvent or an oil-based solvent, but an aqueous solvent is preferred. When the solvent is an aqueous solvent, the environmental load can be further reduced. Examples of the aqueous solvent include water and alcohol.

[0043] The ink may contain a plasticizer, a drying agent, a stabilizer, and the like, as required. The ink may or may not further contain a biomass component, but from the viewpoint of reducing the environmental impact, it is preferable that the ink further contains a biomass component. Here, the biomass component refers to a component obtained from biological resources (biomass) such as cotton, pulp, rice bran, vegetable oil, and angiosperm seeds. The ink layer 20 may be composed of a single layer or multiple layers. When monochromatic printing is performed on the base layer 30, the ink layer 20 is composed of a single layer. When multicolor printing is performed on the base layer 30, the ink layer 20 is composed of multiple layers. In this case, for example, a first ink layer may be formed by performing solid white printing on the entire surface of the base layer 30, and a second ink layer comprising letters, pictures, etc. may be formed on the first ink layer. In addition, a layer of ink containing a black pigment such as black carbon or metal powder may be provided for light blocking. The ink layer 20 may be provided only on a part of the surface of the base material layer 30, or may be provided on the entire surface of the base material layer 30.

[0044] The thickness of the ink layer 20 is not particularly limited and may be adjusted as needed, but from the viewpoint of concealing the color of the contents, it is preferably 0.1 μm or more, more preferably 0.5 μm or more, and particularly preferably 1 μm or more. From the viewpoint of recyclability, the thickness of the ink layer 20 is preferably 5 μm or less, more preferably 4 μm or less, and particularly preferably 3 μm or less.

[0045] The ink layer 20 can be formed by a conventionally known printing method such as gravure printing, offset printing, or flexographic printing.

[0046] (3) Base material layer The base layer 30 may be a film base material made of a resin material or a paper base material. Examples of the resin material include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin resins such as polyethylene and polypropylene, polyamide resins such as polystyrene and nylon 66, polycarbonate resin, polyacrylonitrile resin, and polyimide resin. The above resin material is processed into a film and used as a film substrate. The resin material is preferably a polyolefin resin such as polyethylene or polypropylene. Examples of polyethylene include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer. Examples of polypropylene resins include homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymers, etc. Examples of α-olefins include ethylene, 1-butene, etc. Among the polyolefin resins, polypropylene is preferred from the viewpoint of heat resistance. Among polypropylenes, when emphasis is placed on the rigidity and heat resistance of the packaging bag obtained using the packaging film 100, it is preferable to use homopolypropylene.

[0047] The resin material may be a non-recycled resin, a recycled resin, or a mixture thereof. When using recycled resin for the base material layer 30, which does not come into contact with the contents, it is acceptable to use material recycled resin (material recycled resin), but it is preferable to use chemically recycled resin (chemically recycled resin) from the standpoints of hygiene and quality. The non-recycled resin may be a petroleum-derived resin obtained using petroleum-derived raw material monomers, a biomass-derived resin obtained using biomass-derived raw material monomers, or a mixture thereof, but from the viewpoint of reducing the environmental load, a biomass-derived resin is preferable. The chemically recycled resin may be composed of a single chemically recycled resin, or may be composed of a mixture of multiple types of chemically recycled resins. The material recycled resin may be composed of a single material recycled resin, or may be composed of a mixture of multiple types of material recycled resins.

[0048] The paper substrate is a substrate containing paper, and paper refers to a material containing plant-derived pulp as a main component, where the main component refers to a component containing plant-derived pulp at 50% by mass or more. By including a paper substrate in the packaging film 100, it is possible to contribute to reducing the amount of plastic material used. Specific examples of paper substrates include fine paper, special fine paper, coated paper, art paper, cast coated paper, construction paper, kraft paper, and glassine paper. The paper substrate may or may not further have a coating layer at least on the sealant layer 70 side of the paper. By having the paper substrate further have a coating layer, it is possible to prevent the anchor coating layer 40 from penetrating into the paper and also to fulfill the role of filling in unevenness in the paper, allowing the anchor coating layer 40 to be formed uniformly without defects. The coating layer may further contain a binder resin and, if necessary, a filler. Examples of binder resins include various copolymers such as styrene-butadiene copolymer, styrene-acrylic copolymer, and ethylene-vinyl acetate copolymer, polyvinyl alcohol resins, and cellulose resins. Examples of fillers include kaolin, calcium carbonate, talc, and mica. If the paper substrate does not have a coating layer, discoloration of the paper due to retort treatment of the packaging film 100 will be less likely to occur.

[0049] The base layer 30 may be composed of a single layer or multiple layers.

[0050] The base layer 30 may further contain additives such as fillers, antistatic agents, plasticizers, lubricants, light-shielding pigments, and antioxidants, as needed. The substrate layer 30 may be colored. When the substrate layer 30 is white, the print can be made to look clearer. When the substrate layer 30 contains a light-blocking pigment, the substrate layer 30 can function as a light-blocking layer.

[0051] The content of the resin material in the base layer 30 is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0052] When the base material layer 30 is a film base material made of a resin material, it may be a non-stretched film or a stretched film. The stretched film may be a uniaxially stretched film or a biaxially stretched film. When the base material layer 30 is a uniaxially stretched film, it is possible to improve the tearability and heat resistance of the packaging film 100. When the base material layer 30 is a biaxially stretched film, it is possible to improve the mechanical strength and dimensional stability of the packaging film 100.

[0053] When an adhesive layer is provided on the surface of the base material layer 30, in order to enhance adhesion to the adhesive layer 60, various pretreatments such as corona treatment, plasma treatment, ozone treatment, and flame treatment may be performed on the surface on the adhesive layer 60 side, or a coating layer such as an easy-adhesion layer may be provided.

[0054] The thickness of the substrate layer 30 is not particularly limited. From the viewpoint of reducing materials to reduce the environmental impact and from the viewpoint of obtaining excellent heat resistance, impact resistance, and gas barrier properties, the thickness of the substrate layer 30 may be 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, or 40 μm or more. Furthermore, from the viewpoint of reducing the amount of plastic used and thereby reducing the environmental impact, the thickness of the substrate layer 30 may be 100 μm or less, 60 μm or less, or 50 μm or less.

[0055] (4) Anchor coat layer The anchor coat layer 40 is a layer for further improving the adhesion between the base layer 30 and the gas barrier layer 50 , and is provided between the base layer 30 and the gas barrier layer 50 .

[0056] The material constituting the anchor coat layer 40 is not particularly limited as long as it can improve the adhesion between the base layer 30 and the gas barrier layer 50, but it is preferable that it contains a polyurethane resin. Such polyurethane resins are composed of, for example, a reaction product of an organosilane or organometallic compound, a polyol compound, and an isocyanate compound. The organosilane is, for example, a trifunctional organosilane or a hydrolyzate of a trifunctional organosilane. The organometallic compound is, for example, a metal alkoxide or a hydrolyzate of a metal alkoxide. The metal element contained in the organometallic compound is, for example, Al, Ti, Zr, etc. The organosilane hydrolyzate and the metal alkoxide hydrolyzate each only need to have at least one hydroxyl group. From the viewpoint of transparency, the polyol compound is preferably an acrylic polyol. The isocyanate compound mainly functions as a crosslinking agent or a curing agent. The polyol compound and the isocyanate compound may be a monomer or a polymer.

[0057] The thickness of the anchor coat layer 40 is not particularly limited, but from the viewpoint of improving the adhesion between the base layer 30 and the gas barrier layer 50, it is preferably 20 nm or more, more preferably 50 nm or more, and particularly preferably 100 nm or more. The thickness of the anchor coat layer 40 is preferably 2000 nm or less. When the thickness of the anchor coat layer 40 is 2000 nm or less, the deterioration of the gas barrier property can be more effectively suppressed even after retort treatment, compared to when the thickness exceeds 2000 nm. Furthermore, from the viewpoint of recyclability, the thickness of the anchor coat layer 40 is more preferably 1000 nm or less.

[0058] (5) Gas barrier layer The gas barrier layer 50 is a layer that improves the gas barrier properties of the packaging film 100. The gas barrier properties are barrier properties against gases such as water vapor or oxygen.

[0059] The gas barrier layer 50 includes a vapor-deposited layer. The gas barrier layer 50 may further include a gas barrier coating layer on the vapor-deposited layer. (vapor deposited layer) The vapor-deposited layer is, for example, a vapor-deposited layer of a metal or a vapor-deposited layer of a metal oxide. The metal constituting the vapor-deposited metal layer or vapor-deposited metal oxide layer may be at least one metal selected from the group consisting of Si, Al, Mg, Sn, Ti, and In. The metal oxide is preferably silicon oxide (SiOx), aluminum oxide (AlOx), or a mixture thereof. Both SiOx and AlOx have excellent water vapor barrier properties, and can improve the water vapor barrier properties of the packaging film 100. Of these, SiOx is preferred as the metal oxide. In this case, the packaging film 100 can have even better water vapor barrier properties. The vapor-deposited layer may be composed of a single layer or multiple layers.

[0060] The thickness of the vapor-deposited layer is not particularly limited, but is preferably 5 nm or more. In this case, the deterioration of the gas barrier property of the packaging film 100 can be more sufficiently suppressed even after retort treatment, compared to when the thickness of the vapor-deposited layer is less than 5 nm. The thickness of the vapor-deposited layer is more preferably 8 nm or more, and particularly preferably 10 nm or more. The thickness of the vapor-deposited layer is preferably 300 nm or less. In this case, the deterioration of the gas barrier property of the packaging film 100 can be more effectively suppressed even after retort treatment, compared to when the thickness of the vapor-deposited layer exceeds 300 nm, and the recyclability of the packaging film 100 can also be improved. The thickness of the vapor-deposited layer is more preferably 200 nm or less, and particularly preferably 100 nm or less.

[0061] (Gas barrier coating layer) The gas barrier coating layer has gas barrier properties and is a layer that covers the vapor deposition layer. In this case, the gas barrier properties of the packaging film 100 are improved. Furthermore, the gas barrier coating layer can suppress a decrease in the gas barrier properties of the packaging film 100 even if damage such as cracks occurs in the vapor deposition layer.

[0062] The gas barrier coating layer is formed, for example, from a cured composition containing a water-soluble polymer and at least one of a metal alkoxide and its hydrolysate, and the composition may further contain at least one of a silane coupling agent and its hydrolysate.

[0063] Examples of water-soluble polymers include polyvinyl alcohol, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, etc. Among these, polyvinyl alcohol (PVA) is particularly preferred because it can easily improve the oxygen barrier properties of the gas barrier coating layer.

[0064] Specific examples of metal alkoxides include tetraethoxysilane [Si(OC2H5)4], triisopropoxyaluminum [Al(O-2'-C3H7)3], etc. Tetraethoxysilane (TEOS) and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

[0065] The silane coupling agent includes a compound represented by the following general formula (2). (R 2 Si(OR 3 )3) n ······(2) In the above general formula (2), R 2 represents a monovalent organic group, and R 3 represents an alkyl group or -C2H4OCH3. In this case, it is possible to improve the adhesion between the gas barrier coating layer and the vapor deposition layer, and delamination between layers in the packaging film 100 can be suppressed. In addition, R 2 and R 3 may be the same or different. 3 They may be the same or different from each other. R 2Examples of the monovalent organic group represented by the formula (I) include a monovalent organic functional group containing a vinyl group, an epoxy group, a mercapto group, an amino group, or an isocyanate group. Among these, an isocyanate group is preferred as the monovalent organic functional group. In this case, the composition can have better hot water resistance upon curing, and can impart greater lamination strength to the packaging film 100 even after retort treatment. R 3 Examples of the alkyl group represented by the formula (I) include a methyl group and an ethyl group. Among these, a methyl group is preferred, as this group rapidly undergoes hydrolysis. n represents an integer of 1 or greater. When n is 1, the silane coupling agent represents a monomer, whereas when n is 2 or greater, the silane coupling agent represents a polymer. n is preferably 3. In this case, the hot water resistance of the gas barrier coating layer can be further improved, and it becomes possible to impart greater laminate strength to the gas barrier coating layer even after retort treatment.

[0066] Specific examples of the silane coupling agent include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and 1,3,5-tris(3-methoxysilylpropyl)isocyanurate.

[0067] The gas barrier coating layer can be formed by coating a composition for forming a gas barrier coating layer onto a vapor deposition layer and then heating and drying it. The composition for forming a gas barrier coating layer can be prepared by dissolving a water-soluble polymer in an aqueous solvent (water, a mixed solvent of water and alcohol, etc.) and mixing it with at least one of a metal alkoxide and a silane coupling agent, or a pre-hydrolyzed version of either. This composition (mixed solution) can also contain known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity modifier, and a colorant.

[0068] The thickness of the gas barrier coating layer may be 80 nm or more, 90 nm or more, or 100 nm or more. If the thickness of the gas barrier coating layer is 80 nm or more, it is easy to maintain low oxygen permeability even after retort treatment. The thickness of the gas barrier coating layer may be 1000 nm or less, 700 nm or less, 500 nm or less, or 400 nm or less. If the thickness of the gas barrier coating layer is 1000 nm or less, it is possible to suppress deterioration of gas barrier properties due to cracking of the gas barrier coating layer during coating. From this perspective, the thickness of the gas barrier coating layer may be 80 to 1000 nm.

[0069] (6) Adhesive layer Examples of the adhesive layer 60 include an adhesive layer formed using an adhesive agent and an adhesive layer containing an adhesive resin (hereinafter also referred to as an "adhesive resin layer").

[0070] Examples of adhesives include known adhesives such as urethane adhesives, polyester adhesives, polyamide adhesives, epoxy adhesives, and isocyanate adhesives.

[0071] The adhesive may or may not contain a biomass-derived component, but preferably contains a biomass-derived component from the viewpoint of reducing the environmental impact. Specific examples of adhesives containing a biomass-derived component include the "DIC Dry BM Series" manufactured by DIC Corporation and the "ECOAD Series" manufactured by Toyo Ink Co., Ltd.

[0072] The adhesive may be either an adhesive containing a solvent or an adhesive not containing a solvent (solvent-free adhesive), but from the viewpoint of reducing the environmental load, a solvent-free adhesive is preferred. The adhesive may or may not have gas barrier properties, but from the viewpoint of improving the gas barrier properties of the packaging film 100, it is preferable that the adhesive have gas barrier properties.

[0073] The adhesive resin is a heat-sealable adhesive thermoplastic resin that can be melted by heat and fused to each other. For example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, methylpentene polymer, acid-modified polyolefin resins obtained by modifying polyolefin resins such as polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, and the like can be used.

[0074] The thickness of the adhesive layer 60 is not particularly limited and may be, for example, 1 μm or more. By making the thickness of the adhesive layer 60 1 μm or more, sufficient adhesive strength can be obtained. The thickness of the adhesive layer 60 may be 2 μm or more. From the viewpoint of recyclability, the thickness of the adhesive layer 60 may be 50 μm or less, 5 μm or less, or 3 μm or less.

[0075] (7) Sealant layer The sealant layer 70 may be made of a polyolefin resin film, a polyester resin film, or the like.

[0076] The polyolefin resin film is preferably used in terms of sealing suitability, etc., and contains a polyolefin resin, such as polyethylene or polypropylene. Examples of polyethylene include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer. Examples of polypropylene include homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer, etc. Examples of α-olefin include ethylene, 1-butene, etc. Among the polyolefin resins, polypropylene is preferred from the viewpoint of heat resistance. Among polypropylenes, when emphasis is placed on the rigidity and heat resistance of the packaging bag obtained using the packaging film 100, it is preferable to use homopolypropylene.

[0077] Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0078] The polyolefin resin and polyester resin may be a biomass-derived resin or a mechanically recycled or chemically recycled resin.

[0079] The sealant layer 70 may contain additives as needed, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins. The sealant layer 70 may be colored. When the sealant layer 70 is white, the print can be made to look clearer. When the sealant layer 70 contains a light-blocking pigment, the sealant layer 70 can function as a light-blocking layer.

[0080] The sealant layer 70 may be composed of a single layer or multiple layers.

[0081] When the base layer 30 contains a polyolefin resin, it is preferable that the sealant layer 70 also contains a polyolefin resin. For example, when the base layer 30 contains polypropylene, it is preferable that the sealant layer 70 also contains polypropylene, and when the base layer 30 contains polyethylene, it is preferable that the sealant layer 70 also contains polyethylene. In this case, the proportion of a single material (polyolefin resin) contained in the packaging film 100 can be increased, and the recyclability of the packaging film 100 is further improved.

[0082] The sealant layer 70 may be a stretched film or a non-stretched film, but is preferably a non-stretched film. In this case, the melting point of the sealant layer 70 can be made lower than the melting point of the base material layer 30, which makes it easier to prevent the base material layer 30 from melting when the packaging film 100 is heat-sealed.

[0083] The thickness of the sealant layer 70 is not particularly limited, but from the viewpoint of improving the heat sealability, it is preferably 40 μm or more, and more preferably 50 μm or more. From the viewpoint of improving the flexibility of the packaging film 100, the thickness of the sealant layer 70 is preferably 100 μm or less, and more preferably 80 μm or less.

[0084] (8) Middle class The intermediate layer is a layer provided between the base layer 30 and the adhesive layer 60. When the packaging film 100 further includes a gas barrier layer 50, the intermediate layer may be disposed between the gas barrier layer 50 and the adhesive layer 60, or may be disposed between the gas barrier layer 50 and the base layer 30. The intermediate layer may be a film substrate made of a resin material or a paper substrate. Examples of the resin material include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer. Examples of polypropylene resins include homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymers, etc. Examples of α-olefins include ethylene, 1-butene, etc. Among the polyolefin resins, polypropylene is preferred from the viewpoint of heat resistance. Among polypropylenes, when emphasis is placed on the rigidity and heat resistance of the packaging bag obtained using the packaging film 100, it is preferable to use homopolypropylene.

[0085] The resin material may be a non-recycled resin, a recycled resin, or a mixture thereof. When using recycled resin for the intermediate layer, which does not come into contact with the contents, a material recycled resin may be used, but it is preferable to use a chemical recycled resin from the viewpoints of hygiene and quality. The non-recycled resin may be a petroleum-derived resin obtained using petroleum-derived raw material monomers, a biomass-derived resin obtained using biomass-derived raw material monomers, or a mixture thereof, but from the viewpoint of reducing the environmental load, a biomass-derived resin is preferable. The chemically recycled resin may be composed of a single chemically recycled resin, or may be composed of a mixture of multiple types of chemically recycled resins. The material recycled resin may be composed of a single material recycled resin, or may be composed of a mixture of multiple types of material recycled resins.

[0086] The paper substrate is a substrate containing paper, and paper refers to a material containing plant-derived pulp as a main component, where the main component refers to a component containing plant-derived pulp at 50% by mass or more. By including a paper substrate in the packaging film 100, it is possible to contribute to reducing the amount of plastic material used. Specific examples of paper substrates include fine paper, special fine paper, coated paper, art paper, cast coated paper, construction paper, kraft paper, and glassine paper. The paper substrate may or may not further have a coating layer at least on the sealant layer 70 side of the paper. By having the paper substrate further have a coating layer, it is possible to prevent the anchor coating layer 40 from penetrating into the paper and also to fulfill the role of filling in unevenness in the paper, allowing the anchor coating layer 40 to be formed uniformly without defects. The coating layer may further contain a binder resin and, if necessary, a filler. Examples of binder resins include various copolymers such as styrene-butadiene copolymer, styrene-acrylic copolymer, and ethylene-vinyl acetate copolymer, polyvinyl alcohol resins, and cellulose resins. Examples of fillers include kaolin, calcium carbonate, talc, and mica. If the paper substrate does not have a coating layer, discoloration of the paper due to retort treatment of the packaging film 100 will be less likely to occur.

[0087] The intermediate layer may be composed of a single layer or multiple layers.

[0088] The intermediate layer may further contain additives such as a filler, an antistatic agent, a plasticizer, a lubricant, a light-shielding pigment, and an antioxidant, as required. When the intermediate layer contains a light-shielding pigment, the intermediate layer can function as a light-shielding layer.

[0089] The content of the resin material in the intermediate layer is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0090] When the intermediate layer is a film substrate made of a resin material, it may be a non-stretched film or a stretched film. The stretched film may be a uniaxially stretched film or a biaxially stretched film. When the intermediate layer is a uniaxially stretched film, it is possible to improve the tearability and heat resistance of the packaging film 100. When the intermediate layer is a biaxially stretched film, it is possible to improve the mechanical strength and dimensional stability of the packaging film 100.

[0091] When an adhesive layer is provided on the surface of the intermediate layer, in order to enhance adhesion to the adhesive layer 60, various pretreatments such as corona treatment, plasma treatment, ozone treatment, and flame treatment may be performed on the surface on the adhesive layer 60 side, or a coating layer such as an easy-adhesion layer may be provided.

[0092] The thickness of the intermediate layer is not particularly limited. From the viewpoint of reducing materials to reduce environmental impact and from the viewpoint of obtaining excellent heat resistance, impact resistance, and gas barrier properties, the thickness of the intermediate layer may be 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, or 40 μm or more. Furthermore, from the viewpoint of reducing the amount of plastic used and thereby reducing environmental impact, the thickness of the intermediate layer may be 100 μm or less, 60 μm or less, or 50 μm or less.

[0093] <Packaging products> Next, an embodiment of the packaging product of the present disclosure will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing one embodiment of the packaging product of the present disclosure. In Fig. 2, the same components as those in Fig. 1 are designated by the same reference numerals, and redundant description will be omitted. As shown in Fig. 2, a packaged product 300 includes a packaging bag 200 and a content C contained in the packaging bag 200. The packaging bag 200 shown in Fig. 2 is obtained by using a pair of packaging films 100 and heat-sealing the peripheral edges of the packaging films 100 with the sealant layers 70 facing each other.

[0094] This packaged product 300 includes a packaging bag 200, which can prevent peeling of the ink layer 20 and delamination even when subjected to a retort treatment. Therefore, the packaged product 300 can prevent peeling of the ink layer 20 and delamination even when subjected to a retort treatment. This allows the packaged product 300 to have a long life.

[0095] The packaging bag 200 can also be obtained by folding one packaging film 100 and heat-sealing the peripheral edge of the packaging film 100 with the sealant layers 70 facing each other.

[0096] Examples of the packaging bag 200 include a three-sided pouch, a four-sided pouch, a standing pouch, a gusset pouch, and a pillow package. The packaging bag 200 may further have a spout or a zipper depending on the application.

[0097] The contents C are not particularly limited, and examples of the contents C include food, liquid, medicine, and electronic parts.

[0098] <Summary of this disclosure> The outline of the present disclosure is as follows. [1] An ink layer, a substrate layer, an adhesive layer, and a sealant layer in this order; the ink layer is coated with a coating layer, the coating layer is obtained using a resin composition for a coating layer containing a polyurethane resin and a curing agent, or a resin composition for a coating layer containing a polyamideimide resin; A packaging film, wherein the ink layer is obtained using an ink containing a polyurethane resin. [2] The packaging film according to [1], wherein the ink further contains a curing agent. [3] The packaging film according to [1] or [2], wherein the curing agent contained in the resin composition for the coating layer includes an isocyanate-based curing agent. [4] The packaging film according to [2], wherein the curing agent contained in the ink includes an isocyanate-based curing agent. [5] The packaging film according to any one of [1] to [4], further comprising a gas barrier layer between the adhesive layer and the base layer. [6] The packaging film according to any one of [1] to [5], wherein the base material layer and the sealant layer contain a polyolefin resin. [7] A packaging bag comprising the packaging film according to any one of [1] to [6]. [8] A packaging product comprising the packaging bag described in [7] and contents contained in the packaging bag. [Example]

[0099] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples.

[0100] In the examples and comparative examples, the following base resins, additives and adhesives were used. <Main component of resin composition for coating layer> Polyurethane Medium 1: XGS-922 Medium NT, manufactured by Sakata Inx Corporation Polyurethane medium 2: Riogran R Medium, manufactured by Toyo Ink Co., Ltd. (Polyurethane medium 2: 20% by mass of polyurethane resin, 80% by mass of organic solvent (propyl acetate and ethyl acetate)) Polyamide-imide resin solution: Pyromax HR-15ET (manufactured by Toyobo Co., Ltd., melting point 300°C) diluted with a solvent (ethanol / toluene = 1 / 1 (mass ratio)) so that the non-volatile content was 5 mass%

[0101] <Ink base> Polyurethane ink 1: XGS-922 Red NT (manufactured by Sakata Inx Corporation) Polyurethane ink 2: Riogran F121 Red (manufactured by Toyo Ink Co., Ltd.) (Pigment 10% by mass, polyurethane resin 20% by mass, organic solvent (propyl acetate and ethyl acetate) 70% by mass)

[0102] <Additives> Isocyanate-based curing agent 1: Lamiol R curing agent (a mixture of hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI)) 1% by mass, synthetic resin 34% by mass, organic solvent (ethyl acetate) 65% by mass), manufactured by Sakata Inx Corporation Isocyanate-based curing agent 2: SP curing agent (hexamethylene diisocyanate (HDI) 1% by mass, synthetic resin 49% by mass, organic solvent (ethyl acetate) 50% by mass), manufactured by Toyo Ink Co., Ltd. Isocyanate-based hardener 3: VM hardener (1% by mass of isocyanate compound, 74% by mass of synthetic resin, 25% by mass of organic solvent (ethyl acetate)), manufactured by Toyo Ink Co., Ltd. Anti-blocking agent (B inhibitor): Silica dispersion (25% by weight of silica, 15% by weight of synthetic resin, 60% by weight of organic solvent (ethyl acetate and isopropyl alcohol), manufactured by Toyo Ink Co., Ltd.) Wax dispersion 1:280 additive (polyamide (PA) wax dispersion (25% by weight of polyamide (PA) wax, 75% by weight of organic solvent (ethyl acetate)), manufactured by Toyo Ink Co., Ltd.) Wax Dispersion 2:240 Additive (PA wax and polyethylene (PE) wax dispersion (25% PA wax and PE wax, 75% organic solvent (ethyl acetate and methylcyclohexane)), manufactured by Toyo Ink Co., Ltd.)

[0103] <Adhesive> Dry laminating adhesive 1: This adhesive is made by blending A-626 (manufactured by Mitsui Chemicals, Inc.) as the base agent, A-50 (manufactured by Mitsui Chemicals, Inc.) as the curing agent, and an organic solvent (ethyl acetate) in a mass ratio of 8:1:9.5. The compositions of A-626 and A-50 are as follows: (A-626) 60% by mass of urethane resin precursor, 40% by mass of organic solvent (ethyl acetate) (A-50) 75% by mass of urethane resin precursor, 25% by mass of organic solvent (ethyl acetate) Dry laminating adhesive 2: This adhesive is made by blending A-525 (manufactured by Mitsui Chemicals, Inc.) as the base agent, A-52 (manufactured by Mitsui Chemicals, Inc.) as the curing agent, and an organic solvent (ethyl acetate) in a mass ratio of 9:1:7.5. The compositions of A-525 and A-52 are as follows: (A-525) 50% by mass of urethane resin precursor, 50% by mass of organic solvent (ethyl acetate) (A-52) 75% by mass of urethane resin precursor, 25% by mass of organic solvent (ethyl acetate) Solvent-free adhesive: Aliphatic ester adhesive (product name: DIC Dry (a 2:1 blend of 2K-SF-900A and HA-930B), manufactured by DIC Graphics Corporation) Barrier adhesive: Maxieve C93T, M-100 (Mitsubishi Gas Chemical Company, Inc.)

[0104] <Production of packaging film> Example 1 First, a 20 μm thick stretched polypropylene (OPP) film was prepared as a base layer. Next, a 50 nm thick SiO 2 film was formed on the back surface of the substrate layer using an electron beam heating vacuum deposition device. x The film was formed as a gas barrier layer. On the other hand, a resin composition for a coating layer (OP varnish) was prepared by adding an isocyanate-based curing agent 1 as an additive and ethyl acetate as an organic solvent to a polyurethane-based medium 1 as a main component. At this time, the polyurethane-based medium 1, the isocyanate-based curing agent 1, and the ethyl acetate were mixed in a mass ratio of 100:3:35. In addition, ink was prepared by adding isocyanate-based curing agent 1 as an additive and ethyl acetate as an organic solvent to polyurethane-based ink 1 as the base resin. At this time, polyurethane-based ink 1, isocyanate-based curing agent 1, and ethyl acetate were mixed in a mass ratio of 100:3:35. The ink was then applied to the surface of the substrate layer (the surface of the substrate layer opposite the sealant layer) and dried to form an ink layer with a thickness of 3 μm. Subsequently, a resin composition for a coating layer was applied to the surface of the ink layer and dried to form a coating layer having a thickness of 1 μm. Next, the adhesive 1 for dry lamination was applied onto the gas barrier layer, and then a 70 μm thick unstretched polypropylene (CPP) film was dried. In this way, a packaging film was obtained.

[0105] (Comparative Example 1) A packaging film was obtained in the same manner as in Example 1, except that no additives were added when preparing the resin composition for the coating layer and the ink.

[0106] Example 2 A packaging film was obtained in the same manner as in Example 1, except that when preparing the resin composition for the coating layer, polyurethane medium 2 was used instead of polyurethane medium 1 as the main ingredient, and isocyanate curing agent 2, wax dispersion 1, and wax dispersion 2 were used as additives instead of isocyanate curing agent 1, and when preparing the ink, polyurethane ink 2 was used instead of polyurethane ink 1 as the main ingredient, and isocyanate curing agent 2, wax dispersion 1, and wax dispersion 2 were used as additives instead of isocyanate curing agent 1. In this case, for the resin composition for the covering layer, polyurethane medium 2, isocyanate curing agent 2, wax dispersion 1, wax dispersion 2, and ethyl acetate as an organic solvent were mixed in a mass ratio of 100:3:3:3:35. For the ink, polyurethane ink 2, isocyanate curing agent 2, wax dispersion 1, wax dispersion 2, and ethyl acetate as an organic solvent were blended in a mass ratio of 100:3:3:3:35.

[0107] Example 3 A packaging film was obtained in the same manner as in Example 2, except that isocyanate-based curing agent 3 was used instead of isocyanate-based curing agent 2 as an additive when preparing the resin composition for the coating layer. In this case, for the resin composition for the covering layer, polyurethane medium 2, isocyanate curing agent 3, wax dispersion 1, wax dispersion 2, and ethyl acetate as an organic solvent were mixed in a mass ratio of 100:3:3:3:35.

[0108] Example 4 A packaging film was obtained in the same manner as in Example 2, except that when preparing the resin composition for the coating layer, an antiblocking agent (anti-B agent) was used instead of wax dispersion 1 as an additive, and no additive was added when preparing the ink. In this case, for the resin composition for the covering layer, the polyurethane medium 2, the isocyanate curing agent 2, the B inhibitor, the wax dispersion 2, and ethyl acetate as an organic solvent were mixed in a mass ratio of 100:3:3:3:35. Regarding the ink, polyurethane ink 2 and ethyl acetate as an organic solvent were mixed in a mass ratio of 100:35.

[0109] (Comparative Example 2) A packaging film was obtained in the same manner as in Example 2, except that no additives were added when preparing the resin composition for the coating layer and the ink. At this time, for the resin composition for the covering layer, the polyurethane medium 2 and ethyl acetate as the organic solvent were mixed in a mass ratio of 100:35. Regarding the ink, polyurethane ink 2 and ethyl acetate as an organic solvent were mixed in a mass ratio of 100:35.

[0110] (Comparative Example 3) A packaging film was obtained in the same manner as in Example 2, except that an ink layer was formed using ink on the back side (sealant layer side) of the base layer, a coating layer was formed on the ink layer using a resin composition for the coating layer, and then a gas barrier layer was formed on the coating layer. In this case, for the resin composition for the covering layer, polyurethane medium 2, isocyanate curing agent 2, wax dispersion 1, wax dispersion 2, and ethyl acetate as an organic solvent were mixed in a mass ratio of 100:3:3:3:35. For the ink, polyurethane ink 2, isocyanate curing agent 2, wax dispersion 1, wax dispersion 2, and ethyl acetate as an organic solvent were blended in a mass ratio of 100:3:3:3:35.

[0111] Example 5 A packaging film was obtained in the same manner as in Example 2, except that when preparing the resin composition for the coating layer, a polyamideimide resin solution was used as the main agent instead of polyurethane medium 2, no additives were added, and the thickness of the coating layer was changed from 1 μm to 0.5 μm.

[0112] Example 6 A packaging film was obtained in the same manner as in Example 2, except that the dry laminating adhesive 2 was used instead of the dry laminating adhesive 1 as the material for forming the adhesive layer.

[0113] Example 7 A packaging film was obtained in the same manner as in Example 2, except that a CPP film containing a white pigment (white CPP) (FCMK-VW, manufactured by Futamura Chemical Co., Ltd.) was used instead of the unstretched polypropylene (CPP) film as the material for forming the sealant layer.

[0114] Example 8 A packaging film was obtained in the same manner as in Example 2, except that a solventless adhesive was used instead of the dry laminating adhesive 1 as the material for forming the adhesive layer.

[0115] Example 9 A packaging film was obtained in the same manner as in Example 2, except that a barrier adhesive was used instead of the dry laminating adhesive 1 as the material for forming the adhesive layer.

[0116] Example 10 A packaging film was obtained in the same manner as in Example 2, except that the gas barrier layer was changed from SiOx to aluminum (Al).

[0117] Example 11 A packaging film was obtained in the same manner as in Example 2, except that a 12 μm thick PET film was used as the base layer instead of the 20 μm thick OPP film.

[0118] Example 12 A packaging film was obtained in the same manner as in Example 2, except that a 12 μm thick PET film was used as the base layer instead of the 20 μm thick OPP film, dry laminating adhesive 1 was applied onto the gas barrier layer to attach a PET film (12 μm thick) as an intermediate layer, and then dry laminating adhesive 1 was applied onto the intermediate layer to attach a CPP film as a sealant layer.

[0119] <Evaluation of packaging film> (1) Ink adhesion Test pieces were prepared from the packaging films of Examples 1 to 12 and Comparative Examples 1 and 2. A 15 mm wide, 100 mm long piece of Scotch tape (registered trademark) was attached to the surface of the coating layer of each test piece before and after retort treatment (121°C, 30 minutes) using a hot water storage retort apparatus, and the Scotch tape was peeled off after 10 seconds, and the total area of ​​the deposit (ink) on the surface of the Scotch tape was determined. The ink adhesion was then evaluated according to the total area of ​​the material adhering to the surface of the cellophane tape, based on the following criteria. The results are shown in Tables 1 to 3. The ink adhesion is an index of the degree to which the ink layer is prevented from peeling. (standard) ◎ The total area of ​​the deposits is 150mm 2 less than ○...The total area of ​​the deposits is 150mm 2 More than 300mm 2 less than ×...The total area of ​​the deposits is 300mm 2 End

[0120] (2) Laminate strength Strip-shaped test pieces measuring 15 mm wide and 100 mm long were cut out from the packaging films of Examples 1 to 12 and Comparative Examples 1 to 3. The laminate strength of the test pieces was measured in accordance with JIS Z-1707 before and after retort treatment (121°C, 30 minutes) using a hot water storage retort apparatus. Specifically, the CPP film and the remaining part of the test piece were peeled in opposite directions at a speed of 300 mm / min using a Tensilon tensile tester (product name "Tensilon RTC-1250", manufactured by Orientec Co., Ltd.), and the strength required for peeling (unit: N / 15 mm) was measured as the laminate strength. The laminate strength was evaluated based on the following criteria. This evaluation was made to assess the degree of suppression of delamination of the packaging film. The results are shown in Tables 1 to 3. (standard) 〇···Lamination strength is 2N / 15mm or more ×...Lamination strength is less than 2N / 15mm

[0121] [Table 1]

[0122] [Table 2]

[0123] [Table 3]

[0124] From the results shown in Tables 1 to 3, all of the packaging films of the Examples had ink adhesion of "◎" or "◯" and lamination strength of "◯" even after retort treatment. In contrast, the packaging films of the Comparative Examples had ink adhesion of "×" or lamination strength of "×" after retort treatment. From the above, it was confirmed that the packaging film of the present disclosure can suppress peeling and delamination of the ink layer even when subjected to retort treatment. [Explanation of symbols]

[0125] 10...coating layer, 20...ink layer, 30...base material layer, 40...anchor coat layer, 50...gas barrier layer, 60...adhesive layer, 70...sealant layer, 100...packaging film, 200...packaging bag, 300...packaged product, C...contents.

Claims

1. an ink layer, a substrate layer, an adhesive layer, and a sealant layer in this order; the ink layer is coated with a coating layer, the coating layer is obtained using a resin composition for a coating layer containing a polyurethane resin and a curing agent, or a resin composition for a coating layer containing a polyamideimide resin; A packaging film, wherein the ink layer is obtained using an ink containing a polyurethane resin.

2. The packaging film of claim 1 , wherein the ink further comprises a curing agent.

3. The packaging film according to claim 1 , wherein the curing agent contained in the resin composition for the coating layer includes an isocyanate-based curing agent.

4. The packaging film according to claim 2 , wherein the curing agent contained in the ink includes an isocyanate-based curing agent.

5. The packaging film according to claim 1 , further comprising a gas barrier layer between the adhesive layer and the substrate layer.

6. The packaging film according to claim 1 , wherein the substrate layer and the sealant layer comprise a polyolefin resin.

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

8. A packaging product comprising the packaging bag according to claim 7 and contents contained in the packaging bag.

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