Laminated sheet and press-through pack using the same

Abstract

To provide a laminated sheet used as a lid material of a press-through pack, in which a forger or the like cannot notice that forgery preventing means is applied thereto.MEANS: A laminated sheet used as a lid material of a press-through pack comprises at least a heat seal layer, a metal foil layer, a print base layer, a first printing layer, and a protective layer in this order. The first printing layer comprises a first printing portion which is visible under visible light, and a second printing portion which has the same color as the print base layer under visible light but exhibits a color tone different from that of the print base layer by ultraviolet irradiation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate sheet, and more particularly to a laminate sheet used as a lid material for a press-through pack, and a press-through pack using a laminate sheet as a lid material. [Background technology]

[0002] Press-through packs (also known as PTPs, etc.) are commonly used as packaging for individually storing medicines such as tablets. A press-through pack consists of a storage section that stores the medicine and a lid that covers the storage section, and is configured so that the medicine can be removed by pressing the medicine from the storage section side to break through the lid.

[0003] The lid material of a PTP has a multi-layer structure in which a heat seal layer for attaching the lid material to the container is laminated onto a metal foil layer such as aluminum foil, and usually further includes a printed layer for printing indications such as the name of the drug, etc. This printed layer contains information about the drug contained in the container, the manufacturer, etc.

[0004] In recent years, from the viewpoint of preventing counterfeiting of medicines and preventing medical accidents such as mishandling medicines or exceeding the expiration date, more detailed information has been attached to the container portion or lid of a PTP. For example, a hologram sticker has been attached to the PTP lid (Patent Document 1, etc.), or a latent image pattern has been attached to the surface of the lid by fine embossing (Patent Document 2, etc.). However, problems remain, such as the fact that users may not realize that the medicine is counterfeit even if a counterfeit hologram sticker is attached, and that special equipment is required for fine embossing.

[0005] In response to the above-mentioned problems, Patent Document 3 proposes providing a PTP lid material with a light-emitting layer containing a taggant pigment that emits fluorescence at a specific wavelength. With this PTP lid material, the authenticity can be determined by visually recognizing the fluorescent light emitted from the taggant pigment, and the fluorescent light can be detected by a detection device and compared with data on the genuine product to determine the authenticity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-212811 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-145428 [Patent Document 3] Patent Publication No. 2021-8306 Summary of the Invention [Problem to be solved by the invention]

[0007] The PTP lid material of Patent Document 3 uses a taggant pigment with an average particle diameter larger than the thickness of the luminescent layer, which causes unevenness to form on the surface of the luminescent layer. Therefore, although the presence of the luminescent layer cannot be recognized if it is provided on the entire surface of the lid material, if the luminescent layer is provided in a predetermined pattern such as letters or figures, the presence of the luminescent layer can be seen due to the unevenness, making it possible to know that the lid material has been provided with anti-counterfeiting measures.

[0008] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a laminate sheet to be used as a lid material for a press-through pack, the anti-counterfeiting measures of which cannot be detected. [Means for solving the problem]

[0009] The present inventors have discovered that a press-through pack lid material that does not reveal that it has anti-counterfeiting measures can be realized by providing a fluorescent layer that is not visible under visible light, separate from the portion of the lid material on which drug information is printed as a printing layer. The present invention is based on this discovery. The gist of the present invention is the following decoy. [1] A laminated sheet used as a lid material for a press-through pack, The film comprises at least a heat seal layer, a metal foil layer, a print base layer, a first print layer, and a protective layer in this order; The first printing layer includes a first printing portion that is visible under visible light and a second printing portion that has the same color as the printing base layer under visible light but exhibits a color tone different from that of the printing base layer when irradiated with ultraviolet light. A laminated sheet characterized by: [2] The color difference (ΔE) between the color tone of the printing base layer and the color tone of the second printing part calculated using the color difference formula by CIE DE2000 in accordance with JIS Z 8781-6:2017 * 00 2) is 4.5 or less. [3] The color difference (ΔE) between the color tone of the printing base layer and the color tone of the first printing part calculated using the color difference formula of CIE DE2000 in accordance with JIS Z 8781-6:2017 * 00 The laminate sheet according to [1] or [2], wherein 1) is 10 or more. [4] The laminate sheet according to any one of [1] to [3], wherein the ultraviolet light is UV-A with a wavelength of 375 nm. [5] The laminate sheet according to any one of [1] to [4], wherein the printing base layer contains a white colorant. [6] The laminate sheet according to any one of [1] to [5], wherein the second printed portion contains a fluorescent colorant. [7] The laminate sheet according to [6], wherein the thickness of the second printed portion is 1.0 to 2.0 μm, and the average particle diameter d50 of the fluorescent colorant is equal to or less than the thickness of the second printed portion. [8] The laminate sheet according to [6] or [7], wherein the fluorescent colorant is contained in the second printed portion in an amount of 10 to 80% by mass. [9] The laminate sheet according to any one of [1] to [8], further comprising a second printed layer between the heat seal layer and the metal foil layer.

[10] A lid material made of the laminated sheet according to any one of [1] to [9], a base material having a recess capable of accommodating contents and a flange portion provided around the recess to be bonded to the lid material; Equipped with A press-through pack, in which the heat seal layer of the laminated sheet and the flange portion of the base material are heat-sealed. [Effects of the Invention]

[0010] According to the laminated sheet of the present invention, the first printed layer of the laminated sheet comprises a first printed portion that is visible under visible light and a second printed portion that is the same color as the printing base layer under visible light but takes on a different color tone from the printing base layer when exposed to ultraviolet light.This allows for the application of anti-counterfeiting measures that are not visible under visible light, separate from the portion printed with information about the drug, and therefore the laminated sheet can be suitably used as a lid material for press-through packs where it is impossible to tell that anti-counterfeiting measures have been applied. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view in the thickness direction of a laminated sheet according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view in the thickness direction of a laminated sheet according to another embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view in the thickness direction of a press-through pack according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Laminated sheet] The laminate sheet of the present invention is a laminate sheet used as a lid material for press-through packs. The laminate sheet of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view in the thickness direction of a laminate sheet according to one embodiment of the present invention. The laminate sheet 1 includes, at least in this order, a heat-seal layer 10, a metal foil layer 20, a print base layer 30, a first print layer 40A, and a protective layer 50. The first print layer 40A includes a first print section 41 and a second print section 42. The first print section 41 is visible under visible light, and the information about the drug printed in colored ink such as black ink is textual information or graphic information (e.g., barcode) about the manufacturer. The second print section 42 is the same color as the print base layer 30 under visible light, but exhibits a different color tone from the print base layer 30 when exposed to ultraviolet light. Therefore, when the laminate sheet 1 is observed from the protective layer 50 side, only the first printed portion 41 of the first printed layer 40A is visible under visible light, while the second printed portion 42 is invisible because it is the same color as the printing base layer 30. Even if the second printed portion 42 contains specific text or graphic information, the text information is not visible under visible light, making it impossible to know that the laminate sheet 1 has been treated with anti-counterfeiting measures. On the other hand, when the laminate sheet 1 is irradiated with ultraviolet light from the protective layer 50 side, the second printed portion 42 exhibits a different color tone from the printing base layer, making the text information in the second printed portion 42, which was not visible under visible light, visible, and enabling authentication. The following describes each layer constituting the laminate sheet of the present invention.

[0013] <Heat seal layer> The heat-seal layer is the outermost layer of the laminated sheet and is provided to bond the lid material and the base material by heat-sealing with the flange portion of the base material of the press-through pack. The heat-seal layer can be formed from a conventionally known heat-sealable resin, such as a polyolefin-based (polyethylene-based, polypropylene-based) heat-adhesive resin or a non-stretched or stretched film of such a resin.

[0014] The heat seal layer can be formed by applying a resin coating agent, such as gravure coating, whose main component is a mixture of the same type of resin as that constituting the base material of the press-through pack described below.

[0015] The thickness of the heat seal layer is not particularly limited, but is usually about 1.0 to 50.0 μm, and from the viewpoint of sealing properties, etc., it is more preferably 2.0 to 10.0 μm.

[0016] <Metal foil layer> The metal foil used in the metal foil layer can be a material used in known PTP lid materials, and suitable metal foils include aluminum foil, copper foil, gold foil, and silver foil. In the present invention, a sheet or film containing a metal vapor deposition layer, such as an aluminum vapor deposition layer, can also be used as the substrate. For example, a laminated film in which a metal vapor deposition layer is formed on the surface of a resin film or the like by a known vapor deposition method (PVD, CVD, etc.) can be used as the substrate. Examples of resin films that can be used here include polyamide (nylon), polyethylene (particularly high-density polyethylene), polypropylene (particularly oriented polypropylene), vinyl chloride, ethylene-vinyl alcohol copolymer, polyethylene naphthalate, polyethylene terephthalate, etc. Among these, it is preferable to use aluminum foil for the metal foil layer.

[0017] Specific examples of aluminum foil include pure aluminum (JIS (AA) 1000 series, such as 1N30, 1070, and 1100), Al-Mn series (JIS (AA) 3000 series, such as 3003 and 3004), Al-Mg series (JIS (AA) 5000 series), and Al-Fe series (JIS (AA) 8000 series, such as 8021 and 8079). Among these, aluminum foils made of materials (compositions) such as 1N30, 1070, 1100, 3003, 8021, and 8079 specified by JIS can be preferably used.

[0018] If necessary, the aluminum foil may be subjected to shaping, degreasing, cleaning, anchor coating, overcoating, surface treatment, etc. by known methods.

[0019] The thickness of the metal foil layer is not limited, but is usually about 5 to 500 μm, preferably 100 to 250 μm, taking into consideration moisture resistance, strength, and ease of handling of the press-through pack.

[0020] <Printing base layer> A printing base layer is provided on the underside of the first printing layer of the laminated sheet of the present invention to make the first printing portion of the first printing layer, i.e., drug information printed in colored ink such as black ink, and text information and graphic information (barcodes, etc.) of the manufacturer, etc., easily visible under visible light, and to add design features.

[0021] The printing base layer also serves as a base for the first printing layer and supports the first printing layer. The printing base layer may be provided directly on the surface of the metal foil layer, or may be laminated between the metal foil layer and the printing base layer via a primer layer or the like (not shown) for facilitating the formation of the printing base layer.

[0022] The printing base layer may have any color as long as it achieves the above-mentioned purpose, but is preferably white in consideration of hiding power and visibility of color shift due to the first printing layer. To obtain a white printing base layer, for example, it can be formed by using a white ink. Specifically, the printing base layer can be formed by applying a printing base layer-forming ink, such as a white ink, to the metal foil layer (or to any other layer, if any), and drying the applied ink.

[0023] The method for applying the ink for forming a printing underlayer is not particularly limited, and can be, for example, by a gravure roll coater, offset printing, flexographic printing, UV printing, curtain flow coater, etc. Application by spraying or the like can also be carried out.

[0024] After the ink for forming a printing primer layer is applied, the applied film is dried to form a printing primer layer. The drying method may be either natural drying or heat drying. When heating, the temperature may be, for example, about 50 to 160°C. Furthermore, when applying, the above application and drying may be repeated two or more times to obtain a predetermined thickness.

[0025] The thickness of the printing base layer is not particularly limited, but is usually about 0.5 to 10.0 μm, and from the viewpoint of hiding power, it is preferably 1.0 to 5.0 μm.

[0026] For example, when a white ink is used as the ink for forming the printing underlayer, it is preferable that the colorant component contains a white colorant, and it is possible to use a white ink containing a white colorant, a resin component, a solvent, etc. As the white colorant, inorganic fillers such as titanium oxide, barium titanate, barium sulfate, silicon oxide powder, amorphous silica, talc, and calcined talc can be suitably used.

[0027] As the resin component of the white ink, a transparent resin can be preferably used to fully utilize the effect of the white colorant. Such resins are not particularly limited, but in the present invention, epoxy resins, vinyl chloride-vinyl acetate copolymer resins, nitrocellulose-based resins, polypropylene-based resins, polyvinyl butyral resins, phenolic resins, maleic acid resins, alkyd resins, chlorinated polypropylene resins, acrylic resins, modified olefin-based resins, and the like can be preferably used. These resins can be used alone or in combination of two or more. Among the above-mentioned resins, epoxy resins are preferably used from the viewpoint of coating film performance, etc.

[0028] The content of the white colorant in the white ink can be appropriately set taking into consideration the type of white colorant used and the hiding power. For example, the content of the white colorant in the white ink, calculated as the solid content (components other than the solvent), is usually about 20 to 60 mass %, and in consideration of the hiding power, it is more preferably 30 to 50 mass %.

[0029] Although a solvent for the white ink is not an essential component, a solvent may be included to adjust the viscosity of the white ink to make it easier to apply. Examples of solvents include organic solvents such as aromatic hydrocarbons such as toluene and xylene, alicyclic hydrocarbon solvents such as methylcyclohexane and cyclohexane, ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as methyl ethyl ketone and acetone, and alcohol solvents such as isopropyl alcohol and denatured ethanol. These may be used alone or in combination of two or more.

[0030] The white ink may contain additives such as a curing catalyst, a dispersant, a surfactant, a leveling agent, a surface conditioner, an anti-sagging agent, a thickener, an antifoaming agent, and a lubricant, as long as the additives do not impair the effects of the present invention.

[0031] <1st printing layer> The first printing layer is a layer formed on at least a portion of the surface of the above-mentioned printing base layer, and is composed of a first printing portion that is visible under visible light and a second printing portion that is the same color as the printing base layer under visible light but takes on a different color tone from the printing base layer when exposed to ultraviolet light.

[0032] The first printed portion, which is visible under visible light, is formed by printing with colored ink. The first printed portion can be textual information or graphic information (such as a barcode). For example, textual information can be printed as unchanging information such as the drug name, dosage, efficacy, and effect, or as variable information such as the manufacturing date, lot number, and expiration date. Graphical information can be printed as marks, barcodes, and the like.

[0033] The thickness of the first printed part is usually about 1.0 to 5.0 μm, and preferably 2.0 to 3.0 μm, although it depends on the optical density of the first printed part.

[0034] The color tone of the colored ink can be appropriately determined taking into consideration the visibility and design of the printed character information and graphic information, but it is preferable that the color difference between the color tone of the printing base layer and the color tone of the first printed part is large. The color difference (ΔE ) between the color tone of the printing base layer and the color tone of the first printed part calculated using the color difference formula of CIE DE2000 in accordance with JIS Z 8781-6:2017 is * 00 1) is preferably 5.0 or more, more preferably 10.0 or more. The color difference (ΔE * 00 ) is calculated using the following formula:

number

[0035] Color difference E between the color tone of the printing base layer and the color tone of the first printed part * 00 In order to make 1 preferably 5.0 or more, more preferably 10.0 or more, for example, when the printing base layer is formed with white ink, the first printed portion can be formed with a first printed portion forming ink having a color tone such as black, navy blue, brown, etc. Carbon black, phthalocyanine blue, etc. can be used as the colored pigment used in the first printed portion forming ink having a color tone such as black, navy blue, brown, etc.

[0036] The first printed portion may be formed using only a single color ink for forming the first printed portion, but for example, the character information and the graphic information may be printed in different colors.

[0037] The second printed portion has the same color as the printing base layer under visible light, but exhibits a different color tone from the printing base layer when exposed to ultraviolet light. If the printing base layer is formed using, for example, white ink, the second printed portion can be formed using ink containing a pigment or dye that is white under visible light, but exhibits a different color tone from white when exposed to ultraviolet light. The term "same color" here does not mean the same color in the strict sense, but only if the difference in color tone is not discernible visually. Specifically, the color difference (ΔE ) between the color tone of the printing base layer and the color tone of the second printed portion calculated using the color difference formula of CIE DE2000 in accordance with JIS Z 8781-6:2017 is used. * 00 2) is preferably 4.5 or less, more preferably 4.0 or less. * 00 2 can be calculated using the above formula. The ultraviolet light irradiation is preferably UV-A with a wavelength of 375 nm. Any commercially available device for irradiating UV-A with a wavelength of 375 nm can be used as appropriate, such as a UV-A light manufactured by Contec Co., Ltd.

[0038] The thickness of the second printed portion is not particularly limited, but is preferably 1.0 to 2.0 μm.

[0039] The pigment or dye that is white under visible light but exhibits a different color tone upon ultraviolet irradiation is not particularly limited, and any known pigment or dye can be used, including, for example, sulfides of zinc, cadmium, barium, strontium, yttrium, etc.; fluorescent pigments such as auramine tungstate, rhodamine tungstate, and sodium red lake; and fluorescent colorants such as fluorescent dyes of diaminostilbene, perylene, coumarin, triazole, carbazole, pyridine, naphthalic acid, imidazolone, etc., and derivatives thereof. These fluorescent colorants may be used alone or in combination of two or more.

[0040] Among the above-mentioned fluorescent colorants, fluorescent colorants that have an absorption peak in the UV-A wavelength of 375 nm and emit light in the visible light range are preferably used. Examples of such fluorescent pigments and fluorescent dyes include YS-A4 and ALN-BP4 manufactured by Nemoto Specialty Chemical Co., Ltd.

[0041] The fluorescent colorant preferably has an average particle diameter d50 of 5.0 μm or less, more preferably 2.0 μm or less, and even more preferably 1.0 μm or less. It is particularly preferable to use a fluorescent colorant whose average particle diameter d50 is equal to or less than the thickness of the second printed section. By using a fluorescent colorant whose average particle diameter d50 is equal to or less than the thickness of the second printed section, no part of the fluorescent colorant protrudes from the surface of the second printed section, making the second printed section invisible under visible light and preventing the inclusion of anti-counterfeiting measures. Note that, in this specification, the average particle diameter (d50) refers to the average particle diameter including not only the particle diameter of primary particles but also the particle diameter of secondary particles (aggregates), and is the volume-based d50 value measured by laser diffraction.

[0042] The first and second printed portions can be formed by printing an ink containing the above-described colorant, resin binder, and, if necessary, a solvent onto the printing base layer. Suitable resin binders include epoxy resins, vinyl chloride-vinyl acetate copolymer resins, nitrocellulose resins, polypropylene resins, polyvinyl butyral resins, phenolic resins, maleic acid resins, alkyd resins, chlorinated polypropylene resins, acrylic resins, and modified olefin resins. These resins can be used alone or in combination of two or more. Among the above resins, epoxy resins are preferred from the viewpoint of coating film performance, etc.

[0043] An example of the ink for forming the second printed portion will be described below. Examples of inks for forming the second printed portion include thermosetting compositions and ultraviolet-curing compositions, and as described above, any form is acceptable as long as it has the same color as the printing base layer under visible light but exhibits a different color tone from the printing base layer when exposed to ultraviolet light.

[0044] When the ink for forming the second printed portion is a thermosetting composition, it preferably contains a thermosetting component and a curing catalyst. The thermosetting component preferably contains a thermosetting resin. Known and commonly used thermosetting resins can be used, such as epoxy resins, polyfunctional oxetane compounds, episulfide resins, and melamine resins. Each of these thermosetting resins may be monofunctional or polyfunctional. By including a thermosetting component, it is expected that the heat resistance, chemical resistance, and adhesion of the second printed portion will be improved. One type of thermosetting component may be used alone, or two or more types may be used in combination. The curing catalyst may be any catalyst that accelerates the curing of the thermosetting component, and examples thereof include imidazole compounds and derivatives thereof, amine compounds, hydrazine compounds, phosphorus compounds, etc. These curing catalysts may be used alone or in combination of two or more.

[0045] Furthermore, when the ink for forming the second printed portion is an ultraviolet curable composition, it preferably contains an ultraviolet curable component. The ultraviolet curable component preferably contains an ultraviolet curable resin. Known and commonly used ultraviolet curable resins can be used. Among them, from the viewpoint of curability, a resin that can be cured by a radical addition polymerization reaction with ultraviolet light is preferably used, and more preferably a resin having an ethylenically unsaturated group in the molecule is more preferably used. The ethylenically unsaturated group is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof. The ultraviolet curable component may be used alone or in combination of two or more. If necessary, a known polymerization initiator or the like can also be used.

[0046] When a fluorescent colorant is contained in the ink for forming the second printed portion, the content of the fluorescent colorant can be appropriately set taking into consideration the coatability of the ink when forming the second printed portion, the visibility of the second printed portion when irradiated with ultraviolet light, etc. For example, the content of the fluorescent colorant in the ink, calculated as the solid content (components other than the solvent), is usually about 10 to 80 mass %, and in consideration of hiding power, it is more preferably 20 to 60 mass %.

[0047] <Protective layer> The protective layer is provided to protect the first printed layer from abrasion and the like. The protective layer is preferably provided on the entire surface of the laminate film so as to cover the first printed layer. The protective layer can be formed on the first printed layer (or on the print base layer if the first printed layer is provided only partially) by the same coating method as described above using an ink containing a resin component such as vinyl chloride resin, nitrocellulose resin, epoxy resin, acrylic resin, urethane resin, melamine resin, or ester resin.

[0048] The thickness of the protective layer is not particularly limited, but is usually 0.5 to 10.0 μm, and from the viewpoint of protecting the first printed layer, it is more preferably 1.0 to 5.0 μm.

[0049] FIG. 2 is a cross-sectional view in the thickness direction of a laminate sheet according to another embodiment of the present invention. The laminate sheet 1 includes a heat-seal layer 10, a metal foil layer 20, a print base layer 30, a first printed layer 40A, and a protective layer 50. The laminate sheet 1 also includes a second printed layer 40B between the heat-seal layer 10 and the metal foil layer 20. The second printed layer 40B may consist of only a first printed portion 41 visible under visible light, or, like the first printed layer 40A, may include a first printed portion 41 and a second printed portion 42. The first printed portion 41 and the second printed portion 42, which are optionally provided on the second printed layer 40B, can be configured similarly to the first printed layer 40A described above, and therefore will not be described here.

[0050] [Press-through pack] 3 is a cross-sectional view in the thickness direction of a press-through pack according to one embodiment of the present invention. The press-through pack 2 of the present invention comprises a lid material 60 made of the above-mentioned laminate sheet 1 and a base material 70. The base material 70 has a recess 80 capable of containing contents and a flange portion 90 provided around the recess 80 and bonded to the lid material 60. After contents 100 such as medicine (tablets) are placed in the recess 80, the heat-seal layer 10 of the laminate sheet 1 constituting the lid material 60 is heat-sealed to the flange portion 90 of the base material 70.

[0051] Heat sealing can be performed by any known heating method such as ultrasonic heating sealing, high frequency heating sealing, or electric heater head heating sealing.

[0052] The method for forming the base material having the recess and the flange provided around the recess as described above is not particularly limited, and any known method can be used, such as hot-pressure forming, in which a resin film is heated and pressed against a predetermined mold, drum vacuum forming, in which a material film is pressure-molded into the recess of a drum while being evacuated, plug-type forming, in which a mold with recesses and protrusions is pressed from above and below the resin film, or pin forming. The number and shape of the recesses can be determined appropriately depending on the contents (medicine) to be stored.

[0053] The resin film used for the base material can be any resin film that can be molded as described above, and examples thereof include polyolefins such as polyethylene, polypropylene, and ethylene-α-olefin copolymers; polystyrene, polycarbonate; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacetal; polyamide; polyphenylene ether; polyethersulfone; ethylene-vinyl acetate copolymers; polyvinyl chloride; polyvinylidene chloride; polyphenylene sulfide; polyacrylonitrile; and fluororesins. Among these, it is preferable to select and use a resin with high gas barrier properties. Specific examples include ethylene-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, and liquid crystal polymers. Films made of these resins can also be used in laminated form.

[0054] There are no particular restrictions on the thickness of the resin film used for the base material, but it is usually about 30 to 2000 μm, and preferably 50 to 500 μm. [Example]

[0055] The present invention will now be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following, "parts" and "%" are all by mass unless otherwise specified.

[0056] <Preparation of ink for forming printing base layer> The components were blended according to the formulation in Table 1 below, premixed in a stirrer, and then kneaded in a three-roll mill to obtain inks for forming printing underlayers 1 to 3. The numbers in Table 1 indicate parts by mass.

[0057] [Table 1]

[0058] The components *1 to *6 in Table 1 are as follows: *1: Multifunctional epoxy compound (Mitsubishi Chemical Corporation, jER828) *2: 1-benzyl-2-phenylimidazole (Shikoku Chemicals Co., Ltd., 1B2PZ) *3: Titanium oxide (Sakai Chemical Industry Co., Ltd., R-38L, average particle size: 0.4 μm) *4: Talc (Fimatec Co., Ltd., MP15-38, average particle size: 2.0 μm) *5: Propylene glycol monomethyl ether acetate

[0059] <Preparing the ink for forming the first printing section> As the ink for forming the first printed portion, black ink XOA-1459 type 805 black (manufactured by DIC Graphics Corporation) was used.

[0060] <Preparation of ink for forming second printing section> The components were blended according to the formulation in Table 2 below, premixed in a stirrer, and then kneaded in a three-roll mill to obtain inks 4 to 7 for forming the second printed portion.

[0061] [Table 2]

[0062] The components *1 to *9 in Table 1 are as follows: *1: Multifunctional epoxy compound (Mitsubishi Chemical Corporation, jER828) *2: 1-benzyl-2-phenylimidazole: 1B2PZ manufactured by Shikoku Chemicals Co., Ltd. *5: Propylene glycol monomethyl ether acetate *6: White powder (manufactured by Nemoto Specialty Chemical Co., Ltd., YS-A4, average particle size: 2.0 μm, luminescent color: red) *7: White powder (NEMO Specialty Chemical Co., Ltd., ALN-BP4, average particle size: 2.0 μm, luminescent color: blue) *8: White powder (manufactured by TailNavi Co., Ltd., UV-R, average particle size: 2.0 μm, luminous color: red) *9: White powder (manufactured by Nemoto Specialty Chemical Co., Ltd., SPE-A, average particle size: 4.5 μm, luminescent color: blue)

[0063] [Example 1] A soft aluminum foil (material 1N30) with a thickness of 200 μm was prepared as the metal foil layer, and ink 1 for forming a printing base layer was applied to the entire surface of one side of the foil by screen printing.The foil was then dried at 150°C for 15 seconds in a hot air circulation drying oven to form a printing base layer with a thickness of 3.0 μm. Next, letters and symbols were printed on a part of the surface of the printing base layer by gravure printing using the ink for forming the first printing part, to form a first printing part having a thickness of 2.0 μm. Next, a pattern was printed by gravure printing using ink 4 for forming the second printing part, so as not to overlap the first printing part formed on the surface of the printing base layer, to form a second printing part with a thickness of 2.0 μm, and a laminated sheet was produced.

[0064] In the laminate obtained as described above, the color difference (ΔE * 00 1) and the color difference between the color tone of the printed base layer and the color tone of the second printed part (ΔE * 00 2) were measured using a spectrophotometer CM-5 (manufactured by Konica Minolta Japan, Inc., observation illuminant D65). ΔE in laminate * 00 1 and ΔE * 00 2 was as shown in Table 3 below.

[0065] The obtained laminated sheet was visually observed from the printed side under visible light (indoor fluorescent light) to confirm whether the letters or symbols in the first printed portion were visible (Evaluation 1) and whether the figures in the second printed portion were visible (Evaluation 2). Next, the printed surface was irradiated with UV-A light (manufactured by Contec Co., Ltd.) with a wavelength of 375 nm, and it was visually confirmed whether the pattern in the second printed portion was visible (evaluation 3). The results are shown in Table 3 below.

[0066] [Example 2] A laminate sheet was prepared in the same manner as in Example 1, except that ink 2 for forming a printing base layer was used as the ink for forming a printing base layer. 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0067] [Example 3] A laminate sheet was prepared in the same manner as in Example 1 except that ink 3 for forming a printing base layer was used as the ink for forming a printing base layer. 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0068] [Example 4] A laminate sheet was produced in the same manner as in Example 1 except that ink 5 for forming the second printed portion was used as the ink for forming the second printed portion, and ΔE* 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0069] [Example 5] A laminate sheet was produced in the same manner as in Example 1 except that ink 6 for forming the second printed portion was used as the ink for forming the second printed portion. 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0070] [Example 6] A laminate sheet was produced in the same manner as in Example 1 except that ink 7 for forming the second printed portion was used as the ink for forming the second printed portion, and ΔE* 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0071] [Comparative Example 1] A laminated sheet was prepared in the same manner as in Example 1, except that ink 1 prepared as the ink for forming the printing base layer was used as the ink for forming the second printed portion. 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0072] Comparative Example 2 A laminate sheet was prepared in the same manner as in Example 1, except that ink 2 prepared as the ink for forming the printing base layer was used as the ink for forming the second printed portion. 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0073] Comparative Example 3 A laminate sheet was prepared in the same manner as in Example 1, except that ink 3 prepared as the ink for forming the printing base layer was used as the ink for forming the second printed portion. 00 1. ΔE* 00 2, and evaluations 1 to 3 were carried out. The results are shown in Table 3 below.

[0074] [Table 3]

[0075] As is clear from the evaluation results in Table 3, laminated sheets (Examples 1 to 5) having a first printing layer formed thereon, which has a first printing portion that is visible under visible light and a second printing portion that is the same color as the printing base layer under visible light but takes on a different color tone from the printing base layer when exposed to ultraviolet light, enable authenticity determination and have an anti-counterfeiting effect.

[0076] On the other hand, when a white ink is used as the ink for forming the second printed portion, although it is not visible under visible light because it is the same color as the printing base layer, the second printed portion cannot be seen under visible light, and therefore it can be said that there is no anti-counterfeiting effect (Comparative Examples 1 to 3). Also, when the particle diameter of the fluorescent coloring agent contained in the second printed portion is larger than the thickness of the second printed portion, the second printed portion can be faintly seen under visible light, which indicates that the anti-counterfeiting effect may be reduced in some cases (Example 6). [Explanation of symbols]

[0077] 1. Laminated sheet 2 Press-through pack 10 Heat seal layer 20 Metal foil layer 30 Printing base layer 40A 1st printing layer 40B 2nd printing layer 41 1st Printing Department 42 2nd Printing Department 50 protective layer 60 Lid material 70 Bottom material 80 recess 90 flange 100 Contents

Claims

1. A laminated sheet used as a lid material for a press-through pack, The film includes a heat seal layer, a metal foil layer, a print base layer, a first print layer, and a protective layer, in this order at least; The first printing layer includes a first printing portion that is visible under visible light, and a second printing portion that has the same color as the printing base layer under visible light but exhibits a color tone different from that of the printing base layer when irradiated with ultraviolet light. A laminated sheet characterized by:

2. The color difference (ΔE ) between the color tone of the printing base layer and the color tone of the second printed portion calculated using the color difference formula of CIE DE2000 in accordance with JIS Z 8781-6:2017 ＊ ００ 2) is 4.5 or less.

3. The color difference (ΔE ) between the color tone of the printing base layer and the color tone of the first printed portion calculated using the color difference formula of CIE DE2000 in accordance with JIS Z 8781-6:2017 ＊ ００ 2. The laminate sheet according to claim 1, wherein 1) is 10 or more.

4. 2. The laminated sheet according to claim 1, wherein the ultraviolet light is UV-A with a wavelength of 375 nm.

5. The laminate sheet of claim 1 , wherein the print substrate layer comprises a white colorant.

6. The laminated sheet according to claim 1 , wherein the second printed portion includes a fluorescent colorant.

7. 7. The laminate sheet according to claim 6, wherein the thickness of the second printed portion is 1.0 to 2.0 μm, and the average particle diameter d50 of the fluorescent colorant is equal to or less than the thickness of the second printed portion.

8. The laminate sheet according to claim 6, wherein the fluorescent colorant is contained in the second printed portion in an amount of 10 to 80% by mass.

9. The laminated sheet according to claim 1 , further comprising a second printed layer between the heat seal layer and the metal foil layer.

10. A lid material made of the laminated sheet according to any one of claims 1 to 9, a base material having a recess capable of accommodating contents and a flange portion provided around the recess to be bonded to the lid material; Equipped with A press-through pack, in which the heat seal layer of the laminated sheet and the flange portion of the base material are heat-sealed.

Images