Packaging bag and package

Abstract

To provide a packaging bag capable of sufficiently maintaining designability even when an external force is applied or the packaging bag is torn for unsealing.SOLUTION: The packaging bag 100 includes the base film layer 10, the aluminum-pigment-containing silver ink layer V, the titanium-oxide-pigment-containing white ink layer W, and the sealant layer 20, and includes the seal section 101 constituted by the pair of laminated films 300 in which the sealant layers 20 are heat-sealed to each other, and when the seal strength of the seal section 101 is measured in conformity with JISZ1707:2019, the sealant layers 20 are peeled from each other or the laminated films 300 are broken.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a packaging bag and a packaging body. [Background technology]

[0002] Aluminum foil has high gas barrier properties and light blocking properties and is widely used as a material for packaging bags. On the other hand, a silver ink layer containing an aluminum pigment is known as an alternative to aluminum foil to reduce environmental impact and improve recyclability. Patent Document 1 discloses a food package that includes a packaging bag with a silver ink layer and has improved durability against retort treatment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7268290 Summary of the Invention [Problem to be solved by the invention]

[0004] Packaging bags using laminated films are known, each having a silver ink layer and a white ink layer superimposed on a base film layer to adjust the metallic luster of the silver ink layer containing an aluminum pigment. However, because the white ink layer is weaker than the silver ink layer, even if the sealant layers in the packaging bag have high sealing strength, coagulation and peeling may occur in the white ink layer when external force is applied during transportation, etc. This raises concerns about impairing the design of the packaging bag. The present disclosure provides packaging bags and packages that can fully maintain their design even when subjected to external force or when torn to open. [Means for solving the problem]

[0005] One aspect of the present disclosure provides a packaging bag having a base film layer, a silver ink layer containing an aluminum pigment, a white ink layer containing a titanium oxide pigment, and a sealant layer, each of which has a seal portion formed of a pair of laminated films in which the sealant layers are heat-sealed together, and in which, when the seal strength of the seal portion is measured in accordance with JIS Z 1707:2019 "General rules for plastic films for food packaging," the sealant layers peel off from each other or the laminated film ruptures.

[0006] When the seal strength of the sealed portion of the packaging bag is measured, the sealant layers formed by a pair of laminated films peel off from each other or the laminated films rupture. This packaging bag can suppress cohesive peeling of the white ink layer. This suppresses the occurrence of lifting due to cohesive peeling of the white ink layer upon impact or opening, and therefore the packaging bag has excellent design properties.

[0007] One aspect of the present disclosure provides a package including the packaging bag described above and an item accommodated in a storage section of the packaging bag. Because the package includes the packaging bag, the white ink layer is prevented from floating up due to aggregation and peeling upon impact or when the package is opened, and therefore the package has excellent design properties. [Effects of the Invention]

[0008] The present disclosure can provide a packaging bag and a package that can fully maintain their design even when subjected to external force or when torn to open. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are diagrams illustrating an example of a packaging bag and a packaging body. [Figure 2] FIG. 10 is a perspective view showing another example of a packaging bag. [Figure 3] FIG. 1 is a cross-sectional view showing an example of a laminated film. [Figure 4] FIG. 2 is a cross-sectional view showing another example of a laminated film. [Figure 5] This is a photograph of the peeled surface of a seal that was evaluated as "A" after rupture following seal strength measurement. [Figure 6] This is a photograph of the peeled surface of a seal that was evaluated as "B" after breaking after measuring the seal strength. [Figure 7] This is a photograph of the peeled surface of a seal that was evaluated as "C" after breaking after measuring the seal strength. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present disclosure are described below. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. The upper or lower limit of a numerical range specified in this disclosure may be replaced with any value shown in the examples. Furthermore, the upper and lower limits individually described may be combined in any desired manner. Unless otherwise specified, the materials or components exemplified in this disclosure may be used alone or in combination of two or more. The symbol "~" used in a numerical range indicates a numerical range that includes the upper and lower limits. For example, "X~Y" indicates a numerical range "greater than or equal to X and less than or equal to Y." In the description, identical elements or elements having the same function are designated by the same reference numerals, and redundant description is omitted. Furthermore, positional relationships such as up, down, left, and right used in the description are based on the positional relationships shown in the drawings unless otherwise specified.

[0011] FIG. 1 is a diagram showing an example of a packaging bag. The packaging bag 100 is formed by bonding the sealant layers 20 of a pair of laminate films 300 (310) together. The structure of the laminate films 300 (310) may be as described below. The packaging bag 100 includes a sealed portion 101 formed by bonding the peripheral edges of a pair of film-like, approximately rectangular laminate films 300 (310) together, and a storage portion 102 formed between the pair of laminate films 300 (310) by the sealed portion 101. That is, the side edges, bottom edge, and top edge of the packaging bag 100 are sealed by the sealed portion 101. The packaging bag 100 includes a storage portion 102 in which a packaged item (e.g., food) is stored in a non-sealed portion (sheet portion) surrounded by the sealed portion 101. The sealed portion 101 at the bottom edge may be sealed after the packaged item has been filled into the storage portion 102. The sealed portion 101 is formed by heat sealing the sealant layers 20 of a pair of laminated films 300 (310) together.

[0012] The packaging bag 100 may be provided with opening means 120 for making it easier to open. The opening means has a pair of easy-open processed portions 124 consisting of V-shaped notches formed in the sealed portion 101 at the side edge, and a half-cut line 121 between the pair of easy-open processed portions 124 that serves as a slitting path. The half-cut line 121 can be formed using a laser. The easy-open processed portions 124 are not limited to V-shaped notches, and may be U-shaped or I-shaped notches, or may be a group of scars.

[0013] When measuring the seal strength of the seal portion 101 of the packaging bag 100, which is made up of a pair of laminate films 300, 310, the sealant layers 20 peel off from each other or the laminate films 300, 310 rupture. In such a packaging bag, the white ink layer has sufficiently high strength, so that the white ink layer can be prevented from coagulating and peeling off, causing lifting.

[0014] The seal strength of the present disclosure is determined by measuring the force required to break the seal portion 101 formed by a pair of laminate films 300, 310 using a method conforming to "7.4 Heat Seal Strength Test" in JIS Z 1707:2019 "General Rules for Food Packaging Plastic Films." If the sealant layers 20 peel off without the laminate films 300, 310 breaking during this measurement, the stress required for this peeling is the seal strength (= peel strength). On the other hand, if the sealant layers 20 do not peel off and the laminate film 300 or the laminate film 310 breaks, the stress required for this breakage is the seal strength (= breaking strength). In other words, the seal strength of the present disclosure can be said to be the stress required to break the seal portion 101. If the peel strength is greater than the breaking strength, the laminate film 300 or the laminate film 310 will break when the seal strength is measured using the above method. On the other hand, if the breaking strength is greater than the peel strength, the sealant layers 20 will peel off when the seal strength is measured using the above method. Hereinafter, the peel strength and the breaking strength will be collectively referred to as the seal strength.

[0015] If the strength of the white ink layer W is low, the heat-sealed sealant layers 20 do not peel off from each other, or the laminate films 300, 310 do not rupture, and the white ink layer W itself breaks internally, resulting in cohesive peeling, with the white ink adhering to the peeled surface of the sealant layers 20. On the other hand, in the packaging bag 100, the strength of the white ink layer W is sufficiently high, and the sealant layers 20 peel off from each other, or the laminate films 300, 310 rupture. This prevents cohesive peeling of the white ink layer W. In this way, the sealant layers 20 peel off from each other without cohesive peeling of the white ink layer W, or the laminate films 300, 310 rupture, thereby preventing lifting. If the white ink layer W does not peel off from each other and the laminate films 300, 310 rupture, the sealant layers 20 do not necessarily have to peel off from each other. Furthermore, when the white ink layer W does not cohere and peel, and the sealant layers 20 peel off from each other, the laminated films 300, 310 themselves do not need to be broken.

[0016] When measuring the seal strength of the packaging bag 100, cohesive peeling may not occur in the white ink layer W. Such a packaging bag 100 has even better designability because cohesive peeling does not occur in the white ink layer W even when an external force is applied or when the bag is torn to open.

[0017] The seal strength of the sealed portion 101 of the packaging bag 100 may be 10 (N / 15mm) or more, 20 (N / 15mm) or more, 25 (N / 15mm) or more, or 30 (N / 15mm) or more. The sealed portion 101 of the packaging bag 100 having a seal strength within the above range has a sufficiently high seal strength and is therefore suitable for use as a material for packaging. The seal strength of the sealed portion 101 of the packaging bag 100 may be 50 (N / 15mm) or less. An example of the seal strength of the sealed portion 101 of the packaging bag 100 may be 10 to 50 (N / 15mm).

[0018] The packaging body 200 comprises a packaging bag 100 and an item contained in the container 102 of the packaging bag 100. The item is not particularly limited and may be a solid, a liquid, or a mixture thereof. Examples include food, beverages, medicines, electronic devices, etc. The packaging body 200 comprises the packaging bag 100 having a seal portion 101 made up of laminated films 300, 310, which can prevent the white ink layer from flocculating and peeling, thereby providing excellent design.

[0019] The packaging body 200 may be suitable for retort treatment. For example, the retort treatment may involve heating the packaging body 200 for 10 minutes or more in a hot water spray at temperatures exceeding 100°C. Because the strength of the white ink layer W is improved, the packaging body 200 can suppress lifting due to cohesion and peeling of the white ink layer even when subjected to retort treatment. This provides excellent designability.

[0020] The procedure for manufacturing the packaging bag 100 using the laminated films 300, 310 is described below. A pair of laminated films 300, 310 cut to a predetermined shape is prepared as packaging materials. The sealant layers 20 provided on one side of each laminated film 300, 310 are placed opposite each other and bonded together. This forms sealed portions 101 at the upper and side edges, forming an unsealed portion surrounded by the sealed portions 101 in a U-shape. In this manner, a packaging bag 110 is obtained in which only the upper end (or only the lower end) is unsealed, as shown in FIG. 2. In some examples, the packaging bag of this embodiment may have a portion of its periphery unsealed, as shown in FIG. 2. Here, the laminated films 300, 310 are bonded together at the upper end (or lower end) and a sealed portion 101 is also formed at the upper end (or lower end), thereby obtaining the packaging bag 100.

[0021] On the other hand, when obtaining the package 200, the packaged material is filled into the unsealed upper end (or lower end) of the packaging bag 110, and the sealant layers 20 of the pair of laminated films 300, 310 are bonded together at the upper end (or lower end). The package 200 can be obtained by this procedure.

[0022] Fig. 3 is a cross-sectional view showing an example of a laminated film used in the packaging bag 100. Fig. 3 shows a cross-section along the lamination direction (thickness direction) of the laminated film. The laminated film 300 has, in this order, a base film layer 10, a vapor deposition layer 60, a white ink layer W, a silver ink layer V, an adhesive layer S1, an intermediate layer 50, an adhesive layer S2, and a sealant layer 20.

[0023] The laminated film 300 has a laminated structure in which a white ink layer W and a silver ink layer V are laminated in this order from the base film layer 10 side. Hereinafter, this type of laminated structure may be referred to as an "ink laminate WV." The ink laminate WV softens the metallic luster of the surface, further improving the design when a pattern is printed on the metallic luster. An ink layer of a different color may be present between the white ink layer W and the silver ink layer V.

[0024] Examples of the base film layer 10 include polyester films such as PET and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films, polycarbonate films, polyacrylonitrile films, and polyimide films. These may be uniaxially or biaxially stretched or unstretched. Of these, biaxially stretched PET films are preferred from the viewpoints of improving the durability of the laminate films 300 and 310 and imparting rigidity to improve workability.

[0025] The thickness of the base film layer 10 may be 5 μm or more, 7 μm or more, or 10 μm or more. When the thickness of the base film layer 10 is in this range, the processability is even more excellent. The thickness of the base film layer 10 may be 50 μm or less, 25 μm or less, or 20 μm or less. When the thickness of the base film layer 10 is in this range, the occurrence of pinholes due to breakage of the laminate film 300 can be suppressed. The thickness of the base film layer 10 can be, for example, 5 to 50 μm.

[0026] The vapor-deposited layer 60 is a layer vapor-deposited on the base film layer 10, and has barrier properties against oxygen, water, etc. The vapor-deposited layer 60 contains at least one selected from the group consisting of aluminum oxide, silicon oxide, tin oxide, and magnesium oxide. By providing such a vapor-deposited layer 60, the barrier properties of the packaging bag 100 using the laminated film 300 are improved, and the shelf life of the contents can be improved.

[0027] From the viewpoint of high barrier properties, the thickness of the vapor-deposited layer 60 may be, for example, 5 to 300 nm, or 10 to 150 nm. If the thickness is too small, it tends to be difficult to form a vapor-deposited layer 60 with a uniform thickness.

[0028] The vapor deposition layer 60 can be formed on the base film layer 10 by, for example, a conventional vacuum deposition method. A plasma-assisted method or an ion beam-assisted method may also be used. The vapor deposition layer 60 may also be formed by a thin film formation method such as a sputtering method, an ion plating method, or a plasma vapor deposition (CVD) method. Examples of heating methods for the vacuum deposition method include an electron beam heating method, a resistance heating method, and an induction heating method.

[0029] The vapor deposition layer 60 may be a transparent vapor deposition layer having transparency. A transparent vapor deposition layer improves the transparency of the laminated film 300, thereby improving the visibility of the packaging bag 100. This allows the state of the contents to be confirmed without opening the packaging bag 100. The "transparency" of the transparent vapor deposition layer means that visible light is transmitted through it, and it may scatter light to a certain extent. Materials that scatter light, such as those generally referred to as translucent, are also included in the concept of "transparency" in the present disclosure. The visible light transmittance of the transparent vapor deposition layer in the stacking direction in the present disclosure may be, for example, 75% or more, or 80% or more. Visible light in the present disclosure refers to light in the wavelength range of 360 to 740 nm.

[0030] The white ink layer W is formed on the vapor-deposited layer 60. The white ink layer W contains a titanium oxide pigment, which is a white pigment. In addition to the titanium oxide pigment, the white ink layer W may also contain a binder resin or the like to provide fluidity.

[0031] The content of titanium oxide pigment in the white ink layer W may be 50% by mass or more. When the content of titanium oxide pigment is 50% by mass or more, the white ink layer W has an excellent balance between the coatability and color development. From the viewpoint of further improving the color development of the white ink layer W, the content of titanium oxide pigment may be 60% by mass or more, or 70% by mass or more. From the viewpoint of further improving the coatability of the white ink layer W, the content of titanium oxide pigment may be 80% by mass or less.

[0032] The average particle diameter D50 of the titanium oxide pigment may be 0.05 to 1.0 μm, or 0.1 to 0.5 μm. When the average particle diameter of the titanium oxide pigment is within the above range, the white ink layer W has an excellent balance between coatability and color development.

[0033] The silver ink layer V is formed on the white ink layer W. The silver ink layer V contains an aluminum pigment, which is a silver pigment. In addition to the aluminum pigment, the silver ink layer V may also contain a binder resin or the like to provide fluidity.

[0034] The content of the aluminum pigment in the silver ink layer V may be 3% by mass or more, 4% by mass or more, or 6% by mass or more. When the content of the aluminum pigment is within the above range, excellent light-blocking properties are achieved. Furthermore, the content of the aluminum pigment may be 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less. When the content of the aluminum pigment is within the above range, excellent coatability of the silver ink layer V is achieved. An example of the range of the content of the aluminum pigment may be 3 to 60% by mass.

[0035] The average particle diameter D50 of the aluminum pigment may be 3 to 20 μm, or 5 to 17 μm. When the average particle diameter of the aluminum pigment is within the above range, an excellent balance between the coatability and the light-blocking properties of the silver ink layer V is achieved. To improve the strength of the silver ink layer V, the aluminum pigment may be coated with a resin.

[0036] Both the white ink layer W and the silver ink layer V may contain a curing agent. By including a curing agent in the white ink layer W and the silver ink layer V, the strength of the white ink layer W and the silver ink layer V can be improved. Examples of curing agents include aromatic diisocyanates such as tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate; aliphatic diisocyanates such as hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexyl diisocyanate, and pentane-1,5-diisocyanate (Stabio PDI); and polyisocyanate curing agents such as modified versions of these, such as trimethylolpropane trimer, isocyanurate, biuret, and allophanate. These may be used alone or in combination.

[0037] Commercially available curing agents include 24A-100, 22A-75, TPA-100, TSA-100, TSS-100, TAE-100, TKA-100, P301-75E, E402-808, E405-70B, AE700-100, D101, D201, and A201H (manufactured by Asahi Kasei Corporation), Mytec Y260A (manufactured by Mitsubishi Chemical Corporation), Coronate HX, Coronate HL, and Coronate L (manufactured by Tosoh Corporation), Desmodur N75MPA / X (manufactured by Covestro Japan Co., Ltd.), LG Curing Agent B, LG Curing Agent C, and LG Curing Agent D (manufactured by Tokyo Ink Co., Ltd.), SP Curing Agent (manufactured by Artience Corporation), and Lamiol R Curing Agent (manufactured by Sakata Inx Corporation). The presence of a curing agent in the white ink layer W and the silver ink layer V can be confirmed by detecting an isocyanate group by, for example, infrared spectroscopy, nuclear magnetic resonance analysis, LC-MS, or the like.

[0038] The content of the curing agent in the white ink layer W may be 5% by mass or more, or 7% by mass or more, from the viewpoint of improving the strength of the white ink layer W. Furthermore, from the viewpoint of suppressing blocking that makes it difficult to peel the base film layer 10 from the roll when laminating the base film layer 10 coated with the white ink layer W and the intermediate layer 50, the content of the curing agent may be 12% by mass or less, or 10% by mass or less. The content of the curing agent in the white ink layer W may be, for example, 5 to 12% by mass.

[0039] The content of the curing agent in the silver ink layer V may be 8% by mass or more, 9% by mass or more, or 10% by mass or more from the viewpoint of improving the strength of the silver ink layer V. Furthermore, from the viewpoint of suppressing blocking that makes it difficult to peel the base film layer 10 from the roll when laminating the base film layer 10 coated with the silver ink layer V and the intermediate layer 50, the content of the curing agent may be 15% by mass or less, or 13% by mass or less. The content of the curing agent in the silver ink layer V may be, for example, 8 to 15% by mass.

[0040] By adding a curing agent to the silver ink layer V, the curing agent penetrates into the adjacent white ink layer W, further improving the strength of the white ink layer W. This makes it possible to further suppress aggregation and peeling in the white ink layer W in the packaging bag 100. Furthermore, since it is possible to prevent excessive addition of curing agent to the white ink layer W itself, it is possible to achieve both improved coatability by suppressing blocking and improved strength of the white ink layer W. From the perspective of further improving coatability by suppressing blocking and further improving the strength of the white ink layer W, the content of curing agent contained in the silver ink layer V may be equal to or greater than the content of curing agent contained in the white ink layer W.

[0041] The printing method for the white ink layer W and the silver ink layer V is not particularly limited. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. From the viewpoints of productivity and high definition of the image, gravure printing is preferred. The thickness of the white ink layer W and the silver ink layer V may be 1 to 5 μm.

[0042] The intermediate layer 50 can be the same as those exemplified for the base film layer 10. From the viewpoint of improving the durability of the laminated films 300, 310 against impact and bending, the intermediate layer 50 is preferably a biaxially stretched polyamide film.

[0043] The thickness of the intermediate layer 50 may be 5 μm or more, 7 μm or more, or 10 μm or more. When the thickness of the intermediate layer 50 is in this range, the processability is further improved. The thickness of the intermediate layer 50 may be 50 μm or less, or 30 μm or less.

[0044] In the laminate film 300 having the ink laminate WV, an adhesive layer S1 is interposed between the silver ink layer V and the intermediate layer 50. Examples of adhesive materials that can be used include polyester-isocyanate resins, urethane resins, and polyether resins. By interposing the adhesive layer S1 between the silver ink layer V and the intermediate layer 50, the adhesion between the silver ink layer V and the intermediate layer 50 can be further improved. The adhesive layer S1 may contain the above-mentioned curing agent component. Furthermore, the curing agent may penetrate from the adhesive layer S1 into the silver ink layer V. This can further improve the strength of the silver ink layer V.

[0045] The thickness of the adhesive layer S1 is not particularly limited and may be, for example, 0.5 to 5 μm, or 2 to 3 μm. If the thickness of the adhesive layer S1 is 0.5 μm or more, the adhesion between the first resin layer 30 and the sealant layer 20 can be improved, and if it is 5 μm or less, the amount of adhesive used can be reduced.

[0046] The sealant layer 20 is a layer for bonding layers of the laminated film 300 together to produce the packaging bag 100. Examples of components of the sealant layer 20 include thermoplastic resins. Specific examples of suitable resins include polyolefin-based resins such as unoriented polypropylene (CPP), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), and ethylene-α-olefin copolymers; ethylene-based resins such as ethylene-(meth)acrylic acid copolymers; blends of polyethylene and polybutene; homopolypropylene resin (PP); and polypropylene-based resins such as propylene-ethylene random copolymers, propylene-ethylene block copolymers, and propylene-α-olefin copolymers. A mixture of multiple types of these thermoplastic resins may also be used. These thermoplastic resins can be selected appropriately depending on the intended use.

[0047] The thickness of the sealant layer 20 may be 1 to 100 μm, or 50 to 90 μm. The resin constituting the sealant layer 20 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

[0048] An adhesive layer S2 is interposed between the intermediate layer 50 and the sealant layer 20. The material of the adhesive layer S2 can be the same as that of the adhesive layer S1 described above. The adhesive layers S1 and S2 may be the same or different from each other.

[0049] FIG. 4 is a cross-sectional view showing another example of a laminate film used in the packaging bag 100. FIG. 4 shows a cross-section along the lamination direction (thickness direction) of the laminate film. Laminate film 310 has a structure in which the positions of the white ink layer W and the silver ink layer V of laminate film 300 in FIG. 3 are swapped. That is, laminate film 310 has, in this order, a base film layer 10, a vapor deposition layer 60, a silver ink layer V, a white ink layer W, an adhesive layer S1, an intermediate layer 50, an adhesive layer S2, and a sealant layer 20. The layers in laminate film 310 in FIG. 4 can be the same as those in laminate film 300 in FIG. 3.

[0050] The laminated film 310 has a laminated structure in which a silver ink layer V and a white ink layer W are laminated in this order from the base film layer 10 side. Hereinafter, such a laminated structure may be referred to as an "ink laminate VW." By using the ink laminate VW, the metallic luster of the surface of the packaging bag 100 can be emphasized.

[0051] In the laminate film 310 having the ink laminate VW, an adhesive layer S1 is interposed between the white ink layer W and the intermediate layer 50. In this case, the curing agent contained in the adhesive layer S1 may permeate into the adjacent white ink layer W. This can further improve the strength of the white ink layer W. This prevents excessive addition of curing agent to the white ink layer W itself. Therefore, it is possible to achieve both improved coatability by suppressing blocking and improved strength of the white ink layer W.

[0052] In the ink laminate VW, when the silver ink layer V contains a curing agent, the curing agent may penetrate into the adjacent white ink layer W, as in the ink laminate WV. This increases the strength of the white ink layer W. That is, in the ink laminate VW, the curing agent may penetrate into the white ink layer W from both the silver ink layer V and the adhesive layer S1. This increases the strength of the ink laminate VW compared to the ink laminate WV.

[0053] The strength of the white ink layer W in the laminated films 300, 310 can be evaluated by measuring the peel adhesion strength (laminate strength) of the adhesive layer S1, measured in accordance with JIS K 6854-1:1999 "Adhesives - Peel Adhesion Strength Test Method - Part 1: 90-Degree Peel," and visually confirming that the white ink layer W does not cohesively peel. If the strength of the white ink layer W is low, cohesive peeling will occur in the white ink layer W when measuring the laminate strength. On the other hand, if the strength of the white ink layer W is sufficiently high, the base film layer 10 will break before the white ink layer W. In this way, the improved strength of the white ink layer W can be confirmed by the base film layer 10 breaking first when measuring the laminate strength.

[0054] The laminate strength of each of the laminate films 300, 310 having the adhesive layers S1, S2 may be 1.5 (N / 15mm) or more, 1.8 (N / 15mm) or more, or 2.0 (N / 15mm) or more, from the viewpoint of sufficiently improving the strength of the packaging bag 100. The laminate strength may also be 3.5 (N / 15mm) or less. An example of the laminate strength may be 1.5 to 3.5 (N / 15mm).

[0055] It is not essential that the pair of packaging materials constituting packaging bag 100 have the same layer structure, and for example, the pair of packaging materials may be composed of laminate films having different layer structures. For example, laminate film 300 and laminate film 310 may be used as the pair of laminate films.

[0056] Although several examples have been described above, this embodiment is not limited to the above examples. The shape of the packaging bag may be, for example, a four-sided bag, a zipper bag, a standing bag, a gusset bag, a two-sided bag, a three-sided bag, a folded bag, or the like.

[0057] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments.

[0058] The present disclosure includes the following embodiments. [1] A pair of laminated films each having a base film layer, a silver ink layer containing an aluminum pigment, a white ink layer containing a titanium oxide pigment, and a sealant layer, with the sealant layers bonded together; A packaging bag in which, when the seal strength of the pair of laminated films is measured in accordance with JIS Z 1707:2019, the sealant layers peel off from each other or the laminated films break. [2] The packaging bag according to [1], wherein the seal strength is 10 (N / 15 mm) or more. [3] The packaging bag according to [1] or [2], wherein both the silver ink layer and the white ink layer contain a curing agent. [4] The packaging bag according to [3], wherein the content of the curing agent contained in the silver ink layer is equal to or greater than the content of the curing agent contained in the white ink layer. [5] The packaging bag according to [3] or [4], wherein the content of the curing agent in the silver ink layer is 8 to 15% by mass. [6] The packaging bag according to any one of [1] to [5], wherein when the seal strength is measured, no cohesive peeling occurs in the white ink layer. [7] A package comprising the packaging bag according to any one of [1] to [6] above, and an item to be contained in the container of the packaging bag. [8] The package according to [7], which is for retort treatment. [Example]

[0059] The present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to the following examples.

[0060] (Experimental Example 1) [Making laminated film] A laminated film having an ink laminate WV as shown in Figure 3 was produced by the following procedure. A polyethylene terephthalate (PET) film (thickness: 12 μm) was prepared as the base film layer 10. Using a vacuum deposition device using an electron beam heating system, metallic aluminum was evaporated and oxygen gas was introduced to deposit aluminum oxide on one side of the PET film, forming a 15 nm-thick deposition layer composed of aluminum oxide.

[0061] A commercially available polyisocyanate curing agent was added to a commercially available white ink containing titanium oxide pigment to a content of 10 mass % to prepare a white ink composition. The white ink composition was applied to the vapor deposition layer by gravure printing to form a white ink layer on the vapor deposition layer.

[0062] A silver ink composition was prepared by adding 5% by mass of a commercially available polyisocyanate curing agent to a commercially available silver ink containing an aluminum pigment. The silver ink composition was applied to a white ink layer by gravure printing to form a silver ink layer on the white ink layer.

[0063] A biaxially oriented polyamide film (thickness: 25 μm) was prepared as the intermediate layer 50. An unstretched polypropylene film (thickness: 80 μm) was prepared as the sealant layer 20. The silver ink layer and the biaxially oriented polyamide film were bonded together by dry lamination using a two-component curing polyurethane adhesive (product name: "Takelac A-525 / Takenate A-50", manufactured by Mitsui Chemicals, Inc.). In a similar manner, an unstretched polypropylene film was bonded to the side of the biaxially oriented polyamide film opposite the silver ink layer to obtain a laminated film.

[0064] The layer structure of the laminated film in this experimental example is as follows: The laminated film in this experimental example has an ink laminate WV. Base film layer / Vapor deposition layer / White ink layer / Silver ink layer / Adhesive layer / Intermediate layer / Adhesive layer / Sealant layer

[0065] [Measurement of laminate strength and evaluation of fracture state] The prepared laminate film was cut into a width of 15 mm and the laminate strength was measured in accordance with JIS K 6854-1:1999. Specifically, the peel strength of the laminate film was measured between the base film layer and the sealant layer of the laminate film using a tensile tester at an angle of 90°, a tensile speed of 300 mm / min, and room temperature. This peel strength was taken as the laminate strength. After the measurement, the fracture state was visually confirmed. The fracture state was evaluated according to the following two-level criteria. The measurement was performed once each using three sheets of laminate film (n=3). This measurement was considered the evaluation before retort treatment. The measured values ​​and evaluation results of the laminate strength are shown in Table 1. A: The white ink layer did not cohere and peel, and the base film layer broke. B: The white ink layer coagulated and peeled off.

[0066] [Seal strength measurement] The sealant layers of the two laminated films were heat-sealed together to prepare a 15 mm wide measurement sample. Heat-sealing conditions were 210°C, 0.2 MPa, and 1.0 second using a heater-heated sealer (product name: TP-701-B Heat Seal Tester, manufactured by Tester Sangyo Co., Ltd.). The seal strength of the bonded sealant layers of the measurement sample was measured in accordance with "7.4 Heat Seal Strength Test" in JIS Z 1707:2019 "General Rules for Food Packaging Plastic Films." The seal strength was measured using a tensile tester at a peel angle of 90°, a tensile speed of 300 mm / min, and room temperature (20°C). The measured seal strength values ​​are shown in Table 1.

[0067] [Evaluation of fracture state] After the measurement, the fracture state of the samples was visually inspected. The fracture state was evaluated on a three-point scale based on the following criteria. Three measurement samples were used for the measurement (n=3). This measurement was used as an evaluation before retort treatment. The evaluation results are shown in Table 1. A: The sealant layers peeled off, or the laminated film itself broke, and no lifting occurred on the peeled surface. B: The sealant layers peeled off from each other, or the laminated film itself was torn, but part of the peeled surface was raised. C: White ink was attached to both sides of the peeled surface, and the white ink layer coagulated and peeled off.

[0068] The ratings "A" and "B" are superior in design compared to the rating "C", with the rating "A" being the most superior in design. In the evaluation of the rupture state after the seal strength measurement, the ratings "A" and "B" correspond to the examples, and the rating "C" corresponds to the comparative example.

[0069] Figures 5, 6, and 7 show examples of peeled surfaces after seal strength measurements, photographed with a digital camera. Figure 5 shows the peeled surface for a rating of "A," Figure 6 shows the peeled surface for a rating of "B," and Figure 7 shows the peeled surface for a rating of "C." In the photograph for rating "B" shown in Figure 6, lifting has occurred on part of the peeled surface. In the photograph for rating "C" shown in Figure 7, the peeled surface has turned white, and it can be confirmed that the white ink layer has cohesively peeled off. In the photograph for rating "A" shown in Figure 5, the sealant layers have peeled off from each other, so the peeled surface is clean and free of lifting.

[0070] (Experimental Example 2) A laminated film was produced in the same manner as in Example 1, except that the content of the curing agent in the silver ink layer was set to 7% by mass. The lamination strength and seal strength were measured and the state of fracture was evaluated in the same manner as in Example 1. The results are shown in Table 1. (Experimental Example 3) A laminated film was produced in the same manner as in Example 1, except that the content of the curing agent in the silver ink layer was set to 9% by mass. The lamination strength and seal strength were measured and the state of fracture was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0071] (Experimental Example 4) A laminated film was produced in the same manner as in Example 1, except that the content of the curing agent in the silver ink layer was 10% by mass. The lamination strength and seal strength were measured and the state of fracture was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0072] (Experimental Example 5) A laminated film was produced in the same manner as in Example 1, except that the content of the curing agent in the silver ink layer was set to 12% by mass. The lamination strength and seal strength were measured and the state of fracture was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0073] [Table 1]

[0074] In Experimental Examples 1 to 5, the fracture state after measuring the seal strength was either the sealant layers peeling off or the white ink layer cohesively peeling off, but the laminate film itself was not fractured. As shown in Table 1, in Experimental Examples 3, 4, and 5, n1, n2, and n3 all correspond to Examples. On the other hand, in Experimental Examples 1 and 2, n1, n2, and n3 all correspond to Comparative Examples. These results indicate that increasing the content of curing agent in the silver ink layer tends to improve laminate strength. Meanwhile, with regard to seal strength, it was confirmed that increasing the content of curing agent in the silver ink layer made it less likely for the white ink layer to lift off and cause cohesive peeling, resulting in the sealant layers peeling off. This is thought to be due to the fact that increasing the content of curing agent in the silver ink layer allowed some of the curing agent to penetrate into the white ink layer, improving the strength of the white ink layer.

[0075] (Experimental Example 6) [Production of packaging bags and packaging bodies] Two pieces of laminated film, each measuring 100 mm long and 100 mm wide, were cut out from a laminated film prepared using the same procedure as in Experimental Example 1. The sealant layers of the two cut laminated films were placed together, and three of the outer edges were heat-sealed to create a seal width of 10 mm. This produced a packaging bag with a storage compartment between the two laminated films, as shown in Figure 2. The resulting packaging bag was filled with water, and the remaining unheat-sealed edge was heat-sealed to seal the water in the storage compartment. This was done so that no air was trapped in the storage compartment. In this way, a package such as that shown in Figure 1 was produced. The heat-sealing conditions were 210°C, 0.2 MPa, and 1.0 second using a heater-heated sealer (product name: TP-701-B Heat Seal Tester, manufactured by Tester Sangyo Co., Ltd.).

[0076] [Retort processing] The packages prepared under conditions of 121°C for 30 minutes were subjected to retort treatment. A 15 mm wide sample for measuring laminate strength was cut out from the non-sealed portion of the package after retort treatment, and the laminate strength was measured and the fracture state was evaluated in the same manner as in Experimental Example 1. A 15 mm wide sample for measuring seal strength was also cut out from the package after retort treatment, and the seal strength was measured and the fracture state was evaluated in the same manner as in Experimental Example 1. The measurements were carried out three times (n=3) by preparing three retort-treated packages, cutting one sample for measuring laminate strength and one sample for measuring seal strength from each package, and measuring the laminate strength and seal strength. The results are shown in Table 2.

[0077] (Experimental Example 7) A package was produced in the same manner as in Experimental Example 6, except that the content of the curing agent in the silver ink layer was set to 7% by mass. Retort treatment was carried out in the same manner as in Experimental Example 6, and the laminate strength and seal strength were measured and the state of fracture was evaluated. The results are shown in Table 2.

[0078] (Experimental Example 8) A package was produced in the same manner as in Experimental Example 6, except that the content of the curing agent in the silver ink layer was set to 9% by mass. Retort treatment was carried out in the same manner as in Experimental Example 6, and the laminate strength and seal strength were measured and the state of fracture was evaluated. The results are shown in Table 2.

[0079] (Experimental Example 9) A package was produced in the same manner as in Experimental Example 6, except that the content of the curing agent in the silver ink layer was set to 10% by mass. Retort treatment was carried out in the same manner as in Experimental Example 6, and the laminate strength and seal strength were measured and the state of fracture was evaluated. The results are shown in Table 2.

[0080] (Experimental Example 10) A package was produced in the same manner as in Experimental Example 6, except that the content of the curing agent in the silver ink layer was set to 12% by mass. Retort treatment was carried out in the same manner as in Experimental Example 6, and the laminate strength and seal strength were measured and the state of fracture was evaluated. The results are shown in Table 2.

[0081] [Table 2]

[0082] In Experimental Examples 6 to 10, the fracture state after seal strength measurement was either peeling between the sealant layers or cohesive peeling of the white ink layer, but the laminate film itself was not fractured. As shown in Table 2, in Experimental Examples 9 and 10, n1, n2, and n3 all correspond to Examples. Meanwhile, in Experimental Examples 7 and 8, only n3 corresponds to Examples, and n1 and n2 correspond to Comparative Examples. In Experimental Example 6, n1, n2, and n3 all correspond to Comparative Examples. These results confirmed that increasing the content of the curing agent in the silver ink layer improved laminate strength, even after retort treatment. Furthermore, seal strength measurements also confirmed that increasing the content of the curing agent in the silver ink layer caused heat-sealed sealant layers to peel. Therefore, even when retort treatment caused heat damage, increasing the content of the curing agent in the silver ink layer improved the strength of the white ink layer, demonstrating the feasibility of producing a package with excellent design that suppresses cohesive peeling in the white ink layer.

[0083] (Experimental Example 11) A laminated film was produced in the same manner as in Example 5, except that a biaxially oriented polyamide film (thickness: 15 μm) was used as the intermediate layer 50 and an unstretched polypropylene film (thickness: 60 μm) was used as the sealant layer 20. The lamination strength and seal strength were measured and the fracture state was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0084] (Experimental Example 12) Using the laminated film prepared in the same manner as in Experimental Example 11, a package was prepared in the same manner as in Experimental Example 6. Retort treatment was carried out in the same manner as in Experimental Example 6, and the laminate strength and seal strength were measured and the state of fracture was evaluated. The results are shown in Table 3.

[0085] [Table 3]

[0086] In Experimental Examples 11 and 12, the fracture state after measuring the seal strength was that the sealant layers peeled off from each other, but the laminate film itself did not fracture. As shown in Table 3, in Experimental Examples 11 and 12, n1, n2, and n3 all correspond to working examples. These results show that even if the thickness of the intermediate layer and sealant layer is changed, increasing the content of curing agent improves the laminate strength and seal strength, and the fracture state evaluation results become better. Therefore, it is believed that the content of curing agent in the white ink layer and silver ink layer improves the strength of the white ink layer regardless of the film thickness.

[0087] (Reference example) [Blocking evaluation] A white ink layer and a silver ink layer were laminated onto a base film layer using the same procedure as in Experimental Example 1, except that the content of the curing agent in the silver ink layer was 15% by mass. Two such laminates were prepared, and the base film layers and silver ink layers of the two laminates were overlapped and placed in a 60°C thermostatic chamber with a 20 kg weight on top for three days. The laminates were then removed from the thermostatic chamber, and it was confirmed that the two overlapping laminates could be cleanly separated. Furthermore, no stickiness due to the curing agent occurred on the peeling surface. Therefore, even if the laminate with the base film layer and silver ink layer overlapping was wound up on a roll, it is believed that blocking, in which the curing agent seeps out and bonds the silver ink layer to the base film layer, would not occur. [Industrial Applicability]

[0088] To provide a packaging bag and a package that can sufficiently maintain their design even when an external force is applied or when they are torn to open. [Explanation of symbols]

[0089] 100, 110...packaging bag, 200...packaging body, 101...sealed portion, 102...storage portion, 101...sealed portion, 120...opening means, 121...half-cut line, 124...easy-open processing portion, 300, 310...laminated film, 10...base film layer, 20...sealant layer, 50...intermediate layer, 60...vapor deposition layer, S1, S2...adhesive layer, W...white ink layer, V...silver ink layer, WV, VW...ink laminate.

Claims

1. a sealing portion formed of a pair of laminated films each having a base film layer, a silver ink layer containing an aluminum pigment, a white ink layer containing a titanium oxide pigment, and a sealant layer, the sealant layers being heat-sealed together; A packaging bag, wherein when the seal strength of the sealed portion is measured in accordance with JIS Z 1707:2019, the sealant layers peel off from each other or the laminate film breaks.

2. The packaging bag according to claim 1, wherein the seal strength is 10 (N / 15 mm) or more.

3. The packaging bag according to claim 1 or 2, wherein both the silver ink layer and the white ink layer contain a hardener.

4. The packaging bag according to claim 3 , wherein the content of the curing agent contained in the silver ink layer is equal to or greater than the content of the curing agent contained in the white ink layer.

5. The packaging bag according to claim 3, wherein the content of the curing agent in the silver ink layer is 8 to 15% by mass.

6. The packaging bag according to claim 1 or 2, wherein when the seal strength is measured, no cohesive peeling occurs in the white ink layer.

7. A package comprising the packaging bag according to claim 1 or 2 and an item to be contained in the container portion of the packaging bag.

8. 8. The package of claim 7, which is for retort processing.

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