Decorative sheet, packaging box, and packaging body

Abstract

To provide a decorative sheet which has excellent durability while having water-resistant paper.SOLUTION: A decorative sheet 10 has water-resistant paper 11, a resin coat layer 12, a biaxially stretched polypropylene film 13, an adhesive layer 14, a PET film 16, and a metal film 18 in this order. The water-resistant paper 11 and the resin coat layer 12 are brought into direct contact with each other. The resin coat layer 12 is composed of a hot-melt adhesive containing a polyolefin-based resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a decorative sheet, a packaging box, and a packaging body. [Background technology]

[0002] Plastic packaging bags are known as packaging containers for storing packaged items. For example, Patent Document 1 proposes a package that stores wet tissues and has an opening for removing the wet tissues, and has an opening label that is peelably attached around the opening.

[0003] On the other hand, decorative sheets that include a plastic film with a metallic coating having a metallic luster on a paper substrate are known to improve the decorativeness of packaging containers. Patent Document 2 proposes a container using such a decorative sheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-85968 [Patent Document 2] Japanese Patent Application Publication No. 2019-5940 Summary of the Invention [Problem to be solved by the invention]

[0005] If even a portion of plastic containers could be replaced with paper ones, it would be possible to reduce waste and make effective use of resources. However, if a packaging container of the type in which an opening / closing label is repeatedly peeled and attached, as in Patent Document 1, is constructed with a decorative sheet containing paper, as in Patent Document 2, a large load is placed on the area where the opening / closing label is attached. When packaging a packaged item containing moisture in such a packaging container, it is effective to use waterproof paper to improve water resistance. However, it has been found that when waterproof paper is used, laminates such as a metal film provided on the waterproof paper easily peel off, especially in the area where the opening / closing label is attached.

[0006] The present disclosure provides a decorative sheet that has excellent durability while including waterproof paper, and also provides a packaging box and packaging body that have excellent durability. [Means for solving the problem]

[0007] In one aspect, the present disclosure provides a decorative sheet comprising, in this order, waterproof paper, a resin coating layer, a biaxially oriented polypropylene film, an adhesive layer, a PET film, and a metal film, with the waterproof paper and the resin coating layer in direct contact. This decorative sheet has excellent decorative properties due to the inclusion of the metal film. Furthermore, while the surface of waterproof paper is usually smooth and tends to be difficult to adhere to, the decorative sheet has a resin coating layer that is in direct contact with the waterproof paper. The resin coating layer is a resin layer that reinforces the surface of the waterproof paper, thereby enabling sufficient adhesion to the waterproof paper. Furthermore, in addition to the resin coating layer, a biaxially oriented polypropylene film, an adhesive layer, and a PET film are provided between the waterproof paper and the metal film. Therefore, the decorative sheet has excellent durability.

[0008] The resin coating layer in the decorative sheet is preferably made of a hot melt adhesive containing a polyolefin resin. Such a resin coating layer has excellent adhesion to waterproof paper, which further improves the durability of the decorative sheet.

[0009] It is preferable that the resin component contained in the hot melt adhesive penetrates into the waterproof paper by thermocompression bonding, which sufficiently increases the adhesive strength between the resin coating layer and the waterproof paper, thereby further increasing durability.

[0010] The waterproof paper preferably has a pigment-containing layer, and the pigment-containing layer is in direct contact with the resin-coated layer. Having a pigment-containing layer can improve decorativeness. Pigment-containing layers typically contain particulate pigments, resulting in a smooth surface and a tendency for them to be less likely to adhere to adjacent layers. The decorative sheet, which has a resin-coated layer that has excellent adhesion to the waterproof paper, can maintain sufficiently high durability.

[0011] The waterproof paper preferably has a pigment-containing layer, and the resin component of the hot melt adhesive preferably permeates the pigment-containing layer, thereby sufficiently increasing the adhesive strength between the resin-coated layer and the waterproof paper, which is normally difficult to adhere to, and further increasing durability.

[0012] The decorative sheet had an Edgewick value of 1.5 mg / mm when immersed in water at 23°C for 24 hours. 2 It is preferable that the following conditions are satisfied: Such a decorative sheet has even better water resistance.

[0013] The decorative sheet preferably has, on at least one surface thereof, ruled lines including recesses or through-holes. By using such a decorative sheet, assemblies such as packaging boxes can be easily produced.

[0014] The decorative sheet preferably has an ink layer between the waterproof paper and the resin coating layer, which improves the design.

[0015] In one aspect, the present disclosure provides a packaging box including a box body made of any of the decorative sheets described above.

[0016] This packaging box has a box body made of any of the decorative sheets described above. Therefore, it has excellent durability. Therefore, even if the lid label that seals the opening of the box body has an adhesive sealing surface and is repeatedly opened and closed, damage to the decorative sheet that makes up the box body can be sufficiently prevented.

[0017] In one aspect, the present disclosure provides a package including the packaging box described above and an item to be packaged housed in the packaging box. Since the package includes the packaging box described above, the package has excellent durability. [Effects of the Invention]

[0018] It is possible to provide a decorative sheet that has excellent durability while including waterproof paper, and also to provide a packaging box and packaging body that have excellent durability. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view showing a decorative sheet according to an embodiment. [Figure 2] FIG. 2 is a diagram showing a schematic diagram of the internal structure of the pigment-containing layer of the waterproof paper in the decorative sheet of FIG. [Figure 3] 1 shows the results of infrared spectroscopy (IR) measurement of the release surface of the decorative sheet of Example 1. [Figure 4] 1 shows the results of infrared spectroscopy (IR) measurement of the peeled surface of the decorative sheet of Comparative Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings as needed. However, the following embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. In the description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant description will be omitted as the case may be.

[0021] The decorative sheet 10 in Figure 1 comprises, in this order, waterproof paper 11, a resin coating layer 12, a biaxially oriented polypropylene film 13, an adhesive layer 14, a PET film 16, and a metal film 18. From the front surface 10A side of the decorative sheet 10, the waterproof paper 11 comprises, in this order, a resin layer 11a made of resin, a paper layer 11b containing paper material such as resin and pulp, and a pigment-containing layer 11c containing a pigment. Note that "PET" is an abbreviation for polyethylene terephthalate.

[0022] From the viewpoint of improving water resistance, it is preferable that the resin layer 11a does not contain a pigment. The resin contained in the paper layer 11b and the resin constituting the resin layer 11a may be the same type or different types. Examples of the resin constituting the resin layer 11a and the resin contained in the paper layer 11b include acrylic resin.

[0023] Examples of the pigment contained in the pigment-containing layer 11c include white pigments such as kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, and light calcium carbonate, but the types of pigments are not limited to these and include various pigments such as purple pigments and blue pigments.

[0024] The pigment-containing layer 11c may contain one type of pigment alone or a combination of two or more types of pigments. The pigment-containing layer 11c may contain particulate pigments as well as binders that bind the pigments together, fillers, fluorescent dyes, etc. The pigment-containing layer 11c may be a layer known as a clay layer.

[0025] The basis weight of the waterproof paper 11 is, for example, 100 to 800 g / m 2 and 200 to 600 g / m 2 This makes it possible to achieve both sufficient strength and good assembly ease. The thickness of the waterproof paper 11 may be 100 to 800 μm, or may be 200 to 600 μm.

[0026] The Edgewick value of the waterproof paper 11 measured after immersion in water at 23°C for 24 hours is preferably 4 mg / mm 2and more preferably less than 2 mg / mm 2 and more preferably less than 1.6 mg / mm 2 This allows the decorative sheet 10 to have sufficiently high water resistance.

[0027] The Edge Wick value in this specification can be measured by the following procedure. A laminate film is attached to the entire front and back surfaces of the waterproof paper to be measured. Then, it is cut into a rectangle (15 mm x 100 mm) to obtain a test sample. The mass of the test sample is measured before immersion in water. The test sample is immersed in water at 23°C for 1 to 24 hours, and then removed from the water and the mass of the test sample is measured. The Edge Wick value can be calculated from the mass of the test sample before and after immersion in water using the following formula. Edgewick value = difference in mass of test sample before and after immersion / total area of ​​the four edge faces of the waterproof paper after cutting

[0028] The resin layer 11a of the waterproof paper 11 that forms one surface 10A of the decorative sheet 10 is made of resin, and therefore can prevent moisture absorption from the surface 10A. In a modified example, the resin layer 11a may be omitted, and the paper layer 11b may be exposed on the surface 10A. Because the paper layer 11b also contains resin, sufficient water resistance can be maintained even without the resin layer 11a.

[0029] The structure of the waterproof paper is not limited to the above, and various types of waterproof paper that contain a resin component to improve water resistance can be used. Waterproof paper may be produced by a known method, or a commercially available product may be used. Examples of commercially available products include "N Mitsubishi Waterproof" manufactured by Mitsubishi Paper Mills, Ltd., and "Ecovalley V" and "Ecovalley K" manufactured by Nippon Paper Industries Co., Ltd.

[0030] The resin coating layer 12 may be made of a hot melt adhesive. Examples of hot melt adhesives include those containing a polyolefin resin, an ethylene-vinyl acetate resin, an acrylic resin, or a urethane resin as a resin component. Of these, the resin coating layer 12 is preferably made of a hot melt adhesive containing a polyolefin resin. This improves the affinity between the resin coating layer 12 and the biaxially oriented polypropylene film 13 when they are in direct contact with each other, thereby further increasing the adhesion between them.

[0031] The polyolefin resin in this specification contains repeating units of an olefin. For example, it may be a homopolymer of a type of polyolefin (i.e., polyethylene, polypropylene, etc.), or it may be an olefin copolymer. The olefin copolymer has structural units derived from an olefin and structural units derived from a monomer other than an olefin. The structural units derived from an olefin may account for 50% by mass or more of the entire resin.

[0032] The resin coating layer 12 is preferably made of a hot melt adhesive containing a polyethylene resin. This improves flexibility, facilitating folding of the decorative sheet and facilitating the production of packaging boxes. Furthermore, when the packaging box is produced, delamination between layers at the folding portions can be sufficiently suppressed. Furthermore, a hot melt adhesive containing a polyethylene resin allows the resin coating layer 12 and the biaxially oriented polypropylene film 13 to be pressure-bonded together by thermal lamination alone. This simplifies the manufacturing process of the decorative sheet 10. When manufacturing the decorative sheet, the resin coating layer 12 may be formed using a commercially available hot melt adhesive, or a biaxially oriented polypropylene film with a hot melt adhesive layer formed thereon may be combined with the resin coating layer 12 and the biaxially oriented polypropylene film 13. Examples of hot melt adhesives include "Lamytack MSOK" (product name) manufactured by J-Film Co., Ltd. and "7327KA / SA" (product name) manufactured by Cosmo Film Japan LLC.

[0033] The polyethylene resin in this specification contains a methylene repeating unit. For example, it may be an ethylene homopolymer (i.e., polyethylene) or an ethylene copolymer. The ethylene copolymer has structural units derived from ethylene and structural units derived from a monomer other than ethylene. The structural units derived from ethylene may account for 50% by mass or more of the entire resin.

[0034] The resin-coated layer 12 and the pigment-containing layer 11c of the waterproof paper 11 are in direct contact. This allows the resin components that make up the resin-coated layer 12 to smoothly penetrate into the waterproof paper 11. Examples of resin components that penetrate include those that make up the resin in the resin-coated layer 12 (for example, polyolefin-based resins). By allowing such resin components to penetrate and forming a resin-component-impregnated layer in the pigment-containing layer 11c of the waterproof paper 11, the adhesive strength between the waterproof paper 11 and the resin-coated layer 12 can be sufficiently increased. By including such resin components in the waterproof paper 11, the durability of the decorative sheet 10 can be improved.

[0035] 2 shows a schematic diagram of the internal structure of the pigment-containing layer 11c of the waterproof paper 11 in the decorative sheet 10. When a hot-melt adhesive that has been heated and made fluid is thermocompressed onto the surface of the pigment-containing layer 11c, the resin component 63 contained in the hot-melt adhesive permeates into the pigment-containing layer 11c. The pigment-containing layer 11c may contain the resin component only in a portion thereof, or may have a concentration gradient portion in which the concentration of the resin component increases toward the resin coating layer 12. This allows for a sufficiently high adhesive strength with the resin coating layer 12, while also providing a sufficiently high strength at the boundary between the portion containing the resin component 63 and the portion not containing the resin component 63.

[0036] The permeated resin component 63 aggregates and bonds together components, such as the pigment 61 and other components, contained in the pigment-containing layer 11c. This increases the cohesive strength of the components contained in the pigment-containing layer 11c, improving the durability of the pigment-containing layer 11c. The resin component 63 that has permeated into the pigment-containing layer 11c also bonds with the resin component contained in the resin-coated layer 12. This improves the adhesive strength between the waterproof paper 11 and the resin-coated layer 12.

[0037] The thickness of the resin-impregnated layer formed by impregnating the pigment-containing layer 11c with the resin component 63 may be, for example, 10 μm or more, or may be 15 μm or more. Increasing this thickness can further increase the durability of the pigment-containing layer 11c. From the viewpoint of promoting the penetration of the resin component 63 into the pigment-containing layer 11c and increasing the thickness of the resin-impregnated layer, it is preferable that the hot melt adhesive have a low melting point.

[0038] 1, the thickness of the resin coat layer 12 is preferably 5 to 30 μm, and more preferably 10 to 20 μm, which makes it easy to bend and improves the cohesive force of the waterproof paper 11, thereby making it sufficiently durable.

[0039] It is preferable to provide an ink layer partially between the waterproof paper 11 and the resin coating layer 12. This can improve the design. Even if an ink layer is provided partially between the waterproof paper 11 and the resin coating layer 12, the waterproof paper 11 and the resin coating layer 12 are still bonded with high adhesive strength in other parts between the waterproof paper 11 and the resin coating layer 12. Therefore, even if an ink layer is provided partially between the waterproof paper 11 and the resin coating layer 12, good adhesiveness can be maintained.

[0040] The thickness of the biaxially oriented polypropylene film 13 is preferably 5 to 40 μm, and more preferably 10 to 30 μm, which allows for both ease of folding and adhesive strength at a sufficiently high level.

[0041] The adhesive layer 14 functions to bond the biaxially oriented polypropylene film 13 and the PET film 16 together. Examples of adhesives contained in the adhesive layer 14 include polyvinyl alcohol-based adhesives, polyurethane-based adhesives, polyester-based adhesives, polyether-based adhesives, epoxy-based adhesives, polyethyleneimine-based adhesives, and polybutadiene-based adhesives. Of these, it is preferable to include an epoxy-based adhesive from the viewpoint of further improving water resistance. The thickness of the adhesive layer 14 is preferably 1 to 10 μm, and more preferably 3 to 8 μm. This allows for a sufficiently high level of both ease of folding and durability.

[0042] The surface of the PET film 16 facing the adhesive layer 14 may be subjected to at least one treatment selected from chemical treatment, solvent treatment, corona treatment, plasma treatment, and ozone treatment. The thickness of the PET film 16 is not particularly limited and may be, for example, 3 to 50 μm or 6 to 30 μm.

[0043] The metal film 18 may contain aluminum, tin, indium, nickel, copper, silver, gold, platinum, brass, chromium, or zinc, or an alloy of these metals. It may contain one of these metals alone, or two or more of them in combination. The metal film 18 can be produced by, for example, vacuum deposition, sputtering, or ion plating. The thickness of the metal film 18 is preferably 10 to 100 μm. This allows for the production of a decorative sheet 10 with excellent decorative properties due to its metallic luster at low cost.

[0044] A metallized film or metal foil laminated film in which the PET film 16 and metal film 18 are integrated may also be used. This simplifies the manufacturing process of the decorative sheet 10. An ink layer may be provided on the surface 10B of the decorative sheet 10 on the metal film 18 side. This allows decorative sheets with a variety of designs to be obtained. Because the decorative sheet 10 has an excellent aesthetic appearance, it can be suitably used as an exterior material for packaging containers and as a board material for packaging boxes.

[0045] An example of a manufacturing method for the decorative sheet 10 is described below. A resin coating layer 12 is formed on one side of the waterproof paper 11. For example, a hot melt adhesive is applied to the surface of the waterproof paper 11 facing the pigment-containing layer 11c using a hot melt coater or hot melt gun. A biaxially oriented polypropylene film 13 is laminated on top of the applied hot melt adhesive. Alternatively, a laminate having a hot melt adhesive layer provided on one side of the biaxially oriented polypropylene film 13 may be used. In this case, the waterproof paper 11 and the laminate are bonded together so that the hot melt adhesive layer faces the pigment-containing layer 11c of the waterproof paper 11. Using such a laminate simplifies the manufacturing method.

[0046] An adhesive is applied to one side of the biaxially oriented polypropylene film 13 that has been laminated to the waterproof paper 11, and the biaxially oriented polypropylene film 13 is then laminated to a PET film 16, which is a metallized film or a metal foil laminated film, via the adhesive. In this way, a decorative sheet 10 can be produced that has the PET film 16 and metal film 18 on the adhesive layer 14.

[0047] The decorative sheet 10 has good adhesion between the layers (membranes or films) between the waterproof paper 11 and the metal film 18. Therefore, even when the decorative sheet 10 is folded or used continuously under conditions that repeatedly generate tensile stress along the lamination direction, delamination of the decorative sheet 10 can be sufficiently suppressed. This makes it suitable for use, for example, as a board material for packaging boxes to which lid labels are attached. It is particularly suitable as a board material for packaging boxes to which lid labels are repeatedly attached and peeled. Furthermore, since the decorative sheet 10 includes the waterproof paper 11, it can maintain its durability even when in contact with moisture. Therefore, the packaged item may be an impregnated body impregnated with moisture, an aqueous solution, an emulsion, or the like.

[0048] The decorative sheet 10 may be a paper template (backing) having ruled lines on at least one of the surfaces 10A and 10B that serve as starting points for folding. The ruled lines may be grooves (recesses), or perforated through-holes may be formed. This allows packaging boxes to be produced smoothly using the decorative sheet 10.

[0049] To ensure smooth folding while increasing the rigidity of the packaging box, the thickness of the decorative sheet 10 is preferably 500 to 700 μm, and more preferably 500 to 600 μm. The decorative sheet 10 is folded so that the waterproof paper 11 faces inward and the metal film 18 faces outward. This makes it possible to obtain a packaging container and package that can maintain excellent durability even when packaging a moist packaged item. Such a packaging container and package has a metal film 18 on the outer surface, and therefore has excellent aesthetic appeal. Furthermore, the inclusion of the waterproof paper 11 reduces the amount of plastic waste, allowing for efficient use of resources.

[0050] The Edgewick value of the decorative sheet 10 when immersed in water at 23°C for 24 hours is preferably 3.0 mg / mm 2 More preferably, it is 2.0 mg / mm 2 or less, and more preferably 1.5 mg / mm 2 The Edge Wick value of the decorative sheet 10 can be reduced to increase the moisture resistance of the decorative sheet 10. The Edge Wick value of the decorative sheet 10 can be measured using the same method as that for measuring the Edge Wick value of the waterproof paper 11.

[0051] The peel strength between the waterproof paper 11 and the resin-coated layer 12 in the decorative sheet 10 is preferably 3 [N / 15 mm] or more, more preferably 5 [N / 15 mm] or more, and even more preferably 7 [N / 15 mm] or more. In decorative sheets 10 that include waterproof paper 11, the surface of the pigment-containing layer 11c of the waterproof paper 11 is smooth, so the adhesive strength at the adhesive surface with this pigment-containing layer 11c is usually the lowest among multiple adhesive surfaces. Therefore, decorative sheets 10 with the above-mentioned high peel strength can suppress peeling between the waterproof paper 11 and the metal film 18, and therefore have sufficiently excellent durability. The above peel strength is a value measured using the measurement method described in the examples (without water immersion).

[0052] The decorative sheet 10 may be assembled into a packaging box. A packaging box made of the decorative sheet 10, which has excellent durability and water resistance, may be used to package an impregnated object (such as wet tissues) made of a fiber material impregnated with a cleaning liquid such as alcohol or a lotion. In other words, the decorative sheet 10 may be used as a packaging box for such an impregnated object. The decorative sheet 10 maintains sufficient durability even when in contact with liquids such as water or alcohol. However, the uses of the decorative sheet 10 are not limited to this.

[0053] A packaging body according to one embodiment includes a packaging box and a packaged item to be placed in the packaging box. If the packaging box is constructed using the decorative sheet 10, at least a portion of the packaging box can be recycled. The packaging box and the packaging body including the packaging box may be of a type that has an adhesive sealing surface and requires repeated opening and closing of a lid label that seals the opening of the box. In the case of such a packaging box, repeated adhesion and peeling of the lid label's sealing surface to the packaging box places a large load (tensile stress) on the portion where the lid label's sealing surface is adhered. By using the decorative sheet 10 in this portion, delamination and breakage of this portion can be sufficiently suppressed, even when the lid label is repeatedly opened and closed. Therefore, the packaging box and packaging body have sufficiently excellent durability even without providing a reinforcing film on the packaging box. The elimination of the need for a reinforcing film simplifies the manufacturing process of the packaging box (package) and further improves the appearance of the packaging box (package).

[0054] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the decorative sheet may have any layer. Furthermore, the outer shapes of the packaging box and packaging body are not limited to those shown in the drawings. [Example]

[0055] 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.

[0056] [Creating decorative sheets] Example 1 Commercially available waterproof paper ("N Mitsubishi Waterproof" manufactured by Mitsubishi Paper Mills, basis weight 350 g / m 2) was prepared. This waterproof paper had a two-layer structure consisting of a paper layer containing paper materials such as resin and pulp, and a pigment-containing layer containing a pigment (clay). A laminate (Lamytack MSOK (trade name) manufactured by J-Film Inc.) was prepared, in which a hot melt adhesive layer containing polyethylene resin was provided on one side of a biaxially oriented polypropylene film (thickness: 20 μm). The waterproof paper and the laminate were overlapped with each other so that the hot melt adhesive layer of the laminate faced the pigment-containing layer of the waterproof paper, and the laminate was heated and bonded to obtain a laminate.

[0057] A metallized film consisting of a PET film (thickness: 12 μm) with an aluminum vapor-deposited film (thickness: 10-100 nm) formed on it, and a polyurethane-based adhesive (main agent: AD391-A (trade name), curing agent: AD391-B (trade name), both manufactured by Toyo-Morton Co., Ltd.) were prepared. The laminate and the metallized film were bonded by dry lamination, with the PET film and biaxially oriented polypropylene film facing each other via the adhesive. In this way, a decorative sheet was obtained comprising, in this order, waterproof paper, a resin coating layer composed of a hot-melt adhesive, a biaxially oriented polypropylene film, an epoxy-based adhesive layer, a PET film, and a metal film (aluminum vapor-deposited film).

[0058] Example 2 Commercially available waterproof paper ("Ecovalley K" manufactured by Nippon Paper Industries Co., Ltd., basis weight: 400 g / m 2 ) was prepared. As shown in FIG. 1, this waterproof paper had a laminated structure with a resin layer 11a made of resin, a paper layer 11b containing paper material such as resin and pulp, and a pigment-containing layer 11c containing a pigment (clay). Except for using this waterproof paper, a decorative sheet was produced using the same procedure as in Example 1. The decorative sheet of Example 2 had the laminated structure shown in FIG. 1.

[0059] (Comparative Example 1) The waterproof paper used in Example 1 was used as Comparative Example 1.

[0060] (Comparative Example 2) Non-waterproof general paper (weight: 310 g / m2 A polyurethane adhesive (application amount: 4.3 g / m) was applied by dry lamination. 2 The PET film and the metallized film were bonded together so that they faced each other via the adhesive layer. In this way, a decorative sheet with a laminated structure consisting of the general paper, adhesive layer, PET film, and metal film (aluminum vapor deposition film) was obtained.

[0061] (Comparative Example 3) A decorative sheet was produced in the same manner as in Example 1, except that the resin coating layer and biaxially oriented polypropylene film were not provided. That is, a decorative sheet was obtained by bonding a pigment-containing layer of waterproof paper and a PET film of a metallized film with a polyurethane-based adhesive. This decorative sheet had a layered structure consisting of waterproof paper, an adhesive layer, a PET film, and a metal film (aluminum vapor-deposited film).

[0062] Comparative Example 4 The waterproof paper used in Example 2 was used as Comparative Example 4.

[0063] [Measurement of Edgewick value] A laminate film was attached to the entire front and back surfaces of the decorative sheets obtained in each Example and Comparative Example. Test samples were then cut into rectangles (15 mm x 100 mm). The mass of the test samples before immersion in water was then measured. The test samples were then immersed in water at 23°C for 1 to 24 hours, removed from the water, and their masses were measured. The Edgewick value was calculated using the following formula from the masses of the test samples before and after immersion in water. The results are shown in Table 1. Edgewick value = difference in mass of test sample before and after immersion / total area of ​​the four edge faces of the decorative sheet after cutting

[0064] [Peel adhesion strength measurement] The decorative sheets obtained in each example and comparative example were cut to obtain rectangular test samples (15 mm x 100 mm). The peel bond strength of each decorative sheet was measured in accordance with JIS K 6854-1:1999. The test samples after measuring the Edge Wick value were also measured in the same manner. The specific procedure for measuring the peel bond strength was as follows. After peeling between the layers at the edge (the interface between the waterproof paper and the resin coating layer), the peel bond strength between the layers was measured using a tensile tester under conditions of an angle of 180°, a pulling rate of 300 mm / min, and a temperature of 20°C. The measurement results of this peel bond strength are shown in Table 1. In Table 1, "without water immersion" refers to the measurement value when the Edge Wick test was not performed, and "after water immersion" refers to the measurement value after the Edge Wick test was performed. The Edge Wick values ​​in Table 1 are measured in mg / mm 2 " and the numerical unit of peel adhesion strength is "N / 15mm".

[0065] [Table 1]

[0066] When comparing the Edge wick values ​​of Example 1 and Comparative Examples 1, 2, and 3, which all used the same waterproof paper, Example 1, which had a resin coating layer and a biaxially oriented polypropylene film, had the lowest Edge wick value. A similar trend was observed when comparing Example 2 and Comparative Example 4, which also used the same waterproof paper. This confirmed that the Edge wick value could be reduced by providing a resin coating layer and a biaxially oriented polypropylene film.

[0067] From the results of the peel adhesive strength, it was confirmed that Examples 1 and 2 had adhesive strength that was sufficiently higher than that of Comparative Examples 1 to 4. It was also confirmed that Examples 1 and 2 were able to maintain sufficient durability even when in contact with moisture.

[0068] After measuring the peel adhesive strength of Examples 1 and 2 and Comparative Example 3, the peeled surfaces of each measurement sample were visually observed, and it was confirmed that the waterproof paper itself (the pigment-containing layer itself) had torn and peeled off in all cases. IR measurements were performed on the peeled surfaces of Example 1 and Comparative Example 3 (both samples not immersed in water). Figure 3 shows the IR measurement results for the peeled surface of the decorative sheet of Example 1 (absorption spectrum "1" for the waterproof paper side peeled surface, and absorption spectrum "2" for the metal film side peeled surface). Figure 3 also shows the absorption spectrum of the pigment-containing layer side of the waterproof paper used in Example 1 as control "3". According to this result, the waterproof paper itself (absorption spectrum 3), which is the control, has an absorption spectrum of 2900 cm -1 On the other hand, there is no absorption peak around 2900 cm on both the waterproof paper side (absorption spectrum 1) and the metal film side (absorption spectrum 2). -1 An absorption peak was detected around this area. This absorption peak is thought to be due to the stretching vibration of the carbon-hydrogen bond of the alkane due to the resin component that makes up the resin coating layer (polyethylene resin).

[0069] That is, the decorative sheet of Example 1 peeled off at the pigment-containing layer of the waterproof paper, but peaks derived from the resin components that make up the resin coating layer were also detected on the peeled surface of the waterproof paper, indicating that the resin components contained in the polyethylene resin had permeated the waterproof paper. In this way, it is thought that the inclusion of resin components derived from the adjacent resin coating layer in the waterproof paper improves the adhesive strength between the waterproof paper and the resin coating layer, as well as water resistance.

[0070] Figure 4 shows the IR measurement results for the release surfaces of the decorative sheet of Comparative Example 3 (the release surface on the waterproof paper side and the release surface on the metal film side). As a control, Figure 4 also shows the IR measurement results for the pigment-containing layer side of the waterproof paper used in Example 1. The symbols 1, 2, and 3 in Figure 4 have the same meanings as in Figure 3. In Comparative Example 3, the waterproof paper itself tore and peeled off, but both the release surface on the waterproof paper side and the release surface on the metal film side showed spectra similar to those of the waterproof paper itself. Therefore, it is believed that no resin components penetrated from the adjacent adhesive layer into the pigment-containing layer of the waterproof paper. [Industrial Applicability]

[0071] According to the present disclosure, it is possible to provide a decorative sheet that has excellent durability despite having waterproof paper, and also to provide a packaging box and a packaging body that has excellent durability despite having waterproof paper. [Explanation of symbols]

[0072] 10...decorative sheet, 10A, 10B...surface, 11...water-resistant paper, 11a...resin layer, 11b...paper layer, 11c...pigment-containing layer, 12...resin-coated layer, 13...biaxially oriented polypropylene film, 14...adhesive layer, 16...PET film, 18...metal film.

Claims

1. The decorative sheet comprises, in this order, waterproof paper, a resin coating layer made of a hot melt adhesive containing a polyolefin resin, a biaxially oriented polypropylene film, an adhesive layer, a PET film, and a metal film, with the waterproof paper and the resin coating layer being in direct contact with each other.

2. 2. The decorative sheet according to claim 1, wherein a resin component contained in said hot melt adhesive permeates said waterproof paper.

3. 3. The decorative sheet according to claim 1, wherein the waterproof paper has a pigment-containing layer, and a resin component contained in the hot melt adhesive permeates the pigment-containing layer.

4. Edge wick value after immersion in water at 23°C for 24 hours is 1.5 mg / mm ２ The decorative sheet according to any one of claims 1 to 3, wherein:

5. 5. The decorative sheet according to claim 1, having ruled lines including recesses or through-holes on at least one surface.

6. The decorative sheet according to any one of claims 1 to 5, wherein an ink layer is provided in a portion between the waterproof paper and the resin coating layer, and the waterproof paper and the resin coating layer are in direct contact with each other in another portion between the waterproof paper and the resin coating layer.

7. A decorative sheet described in any one of claims 1 to 6, wherein the metal film is a metal vapor deposition film or a metal foil.

8. A packaging box comprising a box body made of the decorative sheet according to any one of claims 1 to 7.

9. A package comprising the packaging box according to claim 8 and an item to be packaged housed in the packaging box.

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