Decorative sheet, packaging box, and packaging body

Abstract

To provide a decorative sheet which can maintain sufficient durability even when being brought into contact with moisture.SOLUTION: A decorative sheet 10 has water-resistant paper 11, a photocurable resin layer 12, an adhesive layer 14, a base material layer 16, and a metal film 18 in this order. The water-resistant paper 11 and the photocurable resin layer 12 are brought into direct contact with each other, and the water-resistant paper 11 contains a resin component constituting a photocurable resin layer 12.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 wet tissues made of a fiber material impregnated with a cleaning solution such as alcohol, or a lotion, etc. For example, Patent Document 1 proposes a package that stores wet tissues and has an opening for removing the wet tissues, and an opening / closing label that is peelably adhered around the opening.

[0003] On the other hand, decorative sheets that have a plastic film with a metallic coating that has a metallic luster on a paper base material are known to improve the design 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 effectively use resources. However, if a container made of a material containing liquid is made of paper, as in Patent Document 1, the liquid will penetrate the paper, making it impossible to maintain sufficient strength. While a laminate of a resin and a paper substrate, as in Patent Document 2, could be considered for reinforcement, the inventors' investigations revealed that the interface between the resin and the paper substrate is prone to peeling, making it difficult to maintain sufficient durability.

[0006] The present disclosure provides a decorative sheet that can maintain sufficient durability even when in contact with moisture. The present disclosure also provides a packaging box and a package that can maintain sufficient durability even when used to package moist items. [Means for solving the problem]

[0007] In one aspect, the present disclosure provides a decorative sheet comprising, in this order, waterproof paper, a photocurable resin layer, an adhesive layer, a substrate layer, and a metal film. This decorative sheet comprises waterproof paper, which has excellent resistance to moisture, and a photocurable resin layer. This photocurable resin layer also has better water resistance than water-soluble resins such as polyvinyl alcohol. Therefore, the decorative sheet can maintain sufficient durability even when in contact with moisture.

[0008] In the decorative sheet, the waterproof paper and the photocured resin layer are in direct contact with each other, and the waterproof paper preferably contains the resin component that constitutes the photocured resin layer. This sufficiently increases the adhesive strength between the photocured resin layer and the waterproof paper, further increasing durability. Furthermore, the water resistance of the waterproof paper is further improved, thereby increasing the water resistance of the decorative sheet.

[0009] It is preferable that the waterproof paper has a pigment-containing layer, and that the resin components constituting the photocured resin layer permeate into the pigment-containing layer. 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. However, by allowing the resin components constituting the photocured resin layer to permeate into the pigment-containing layer, it is possible to sufficiently increase the adhesive strength between the photocured resin layer and the pigment-containing layer, thereby achieving sufficiently high durability. Furthermore, the presence of a pigment-containing layer in the waterproof paper can improve decorativeness.

[0010] The photocured resin layer is preferably made of a UV-cured resin containing a (meth)acrylic resin. Such a UV-cured resin has excellent adhesion and water resistance. Therefore, even if the decorative sheet comes into contact with water, the strength of the decorative sheet can be maintained at a sufficiently high level. The waterproof paper preferably contains a (meth)acrylate monomer and / or a polymer thereof. This further increases the water resistance of the waterproof paper.

[0011] 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.

[0012] 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.

[0013] The decorative sheet preferably has an ink layer between the waterproof paper and the photocurable resin layer, which allows for improved design.

[0014] In one aspect, the present disclosure provides a packaging box including a box body made of any of the decorative sheets described above. This packaging box includes a box body made of any of the decorative sheets described above. Therefore, it has sufficient durability even when packaging a packaged item containing moisture. For example, even if the lid label has an adhesive sealing surface and seals the opening of the box, peeling of the decorative sheet that makes up the box body can be sufficiently prevented.

[0015] In one aspect, the present disclosure provides a package including the packaging box described above and a packaged item housed in the packaging box. Because the packaging includes the packaging box described above, the packaging can maintain sufficient durability even when packaging a packaged item containing moisture. [Effects of the Invention]

[0016] It is possible to provide a decorative sheet that can maintain sufficient durability even when it comes into contact with moisture, and a packaging box and a package that can maintain sufficient durability even when a packaged item containing moisture is packaged. [Brief explanation of the drawings]

[0017] [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 Example 2. [Figure 5] 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

[0018] 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.

[0019] The decorative sheet 10 of FIG. 1 comprises, in this order, a waterproof paper 11, a photocurable resin layer 12, an adhesive layer 14, a base layer 16, and a metal film 18. The waterproof paper 11 comprises, from the front surface 10A of the decorative sheet 10, a paper layer 11a containing a paper material such as resin and pulp, and a pigment-containing layer 11b containing a pigment, in this order. Examples of pigments contained in the pigment-containing layer 11b include white pigments such as kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, and light calcium carbonate. However, the types of pigments are not limited to these, and other pigments include various pigments such as purple pigments and blue pigments. The pigment-containing layer may contain a single pigment selected from the above, or a combination of two or more pigments. The pigment-containing layer 11b may contain particulate pigments, as well as binders, fillers, fluorescent dyes, and the like that bind the pigments together. The pigment-containing layer 11b may also be a layer known as a clay layer.

[0020] The Edgewick value of the waterproof paper 11 measured after immersion in water at 23°C for 24 hours is preferably 4 mg / mm 2 More preferably, it is 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.

[0021] 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

[0022] The basis weight of the waterproof paper 11 is, for example, 100 to 800 g / m 2and 200 to 600 g / m 2 This makes it possible to achieve both sufficient rigidity and good ease of assembly. The thickness of the waterproof paper 11 may be 100 to 800 μm, or may be 200 to 600 μm.

[0023] The paper layer 11a of the waterproof paper 11 that forms one surface 10A of the decorative sheet 10 contains a resin, which prevents moisture absorption from the surface 10A. In a modified example, a resin coating layer made of, for example, an acrylic resin may be provided to cover the surface of the paper layer 11a. The resin contained in the paper layer 11a and the resin that constitutes the resin coating layer may be the same type or different types. An example of the resin contained in the resin coating layer is a (meth)acrylic resin.

[0024] 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.

[0025] The pigment-containing layer 11b of the waterproof paper 11 in the decorative sheet 10 is preferably in direct contact with the photocurable resin layer 12. By providing the waterproof paper 11 with the pigment-containing layer 11b, the decorative sheet 10 can be improved in terms of aesthetic appeal and design. On the other hand, the pigment-containing layer 11b is prone to absorbing moisture, and the inclusion of particulate pigments makes the surface smooth, making adhesion to other layers more likely to be impaired. In this embodiment, the photocurable resin layer 12, which has excellent adhesion to the pigment-containing layer 11b and excellent water resistance, is bonded to the pigment-containing layer 11b, and one side of the pigment-containing layer 11b is entirely covered by the photocurable resin layer 12. This prevents moisture from penetrating the interface between the pigment-containing layer 11b and the photocurable resin layer 12. Therefore, the decorative sheet 10 can maintain its excellent durability even when exposed to moisture.

[0026] The photocured resin layer 12 is composed of a resin cured product obtained by irradiating a photosensitive resin composition with light and curing it. The resin cured product is preferably a UV-cured resin product obtained by irradiating a photosensitive resin composition with ultraviolet light. By forming the photocured resin layer 12 from a UV-cured resin product, water resistance can be further improved. From the same viewpoint, a photoradical polymerization type UV-cured resin is preferable. From the viewpoint of further improving water resistance, the UV-cured resin preferably contains a (meth)acrylic resin. The (meth)acrylic resin can be obtained, for example, as a polymer of a monomer having an acryloyl group and / or a methacryloyl group. The (meth)acrylic resin may also be obtained by polymerizing such a monomer with an oligomer having an acryloyl group and / or a methacryloyl group. Examples of the monomer include a (meth)acrylate monomer, and examples of the oligomer include a (meth)acrylate oligomer.

[0027] The photosensitive resin composition may contain a monomer, an oligomer, an additive containing a photopolymerization initiator, and an organic solvent. The photosensitive resin composition may contain 50 to 90 parts by mass, or may contain 60 to 80 parts by mass, of the monomer relative to 100 parts by mass of the monomer and oligomer combined. This allows the monomer to sufficiently penetrate the waterproof paper 11 while achieving high adhesive strength. The photosensitive resin composition may contain 3 to 20 parts by mass, or may contain 5 to 15 parts by mass of the additive relative to the total of 100 parts by mass.

[0028] Examples of the monomer include acrylic monomers, vinyl monomers, and allyl monomers. Examples of the acrylic monomer include those having an acryloyl group and / or a methacryloyl group as a functional group involved in a photocuring reaction (photopolymerization reaction). In the present disclosure, the acryloyl group and the methacryloyl group may be referred to as a (meth)acryloyl group. The acrylic monomer may be a (meth)acrylic acid ester, an acid amide of a nitrogen-containing compound and (meth)acrylic acid, or (meth)acrylic acid. In the present disclosure, acrylic acid and methacrylic acid may be referred to as (meth)acrylic acid. Furthermore, an acrylic acid ester (or acrylate) and a methacrylic acid ester (or methacrylate) may be referred to as a (meth)acrylic acid ester (or (meth)acrylate).

[0029] The (meth)acrylic acid ester may be a (meth)acrylic acid alkyl ester, and specific examples thereof include (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 8 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate.

[0030] Examples of vinyl-based monomers include those having a vinyl group as a functional group involved in a photocuring reaction (photopolymerization reaction). Examples of vinyl-based monomers include vinyl ethers (e.g., vinyl ethers of monohydric alcohols), vinyl esters (divinyl adipate, divinyl maleate, divinyl phthalate, divinyl isophthalate, divinyl itaconate), and alicyclic vinyl monomers. Examples of allyl-based monomers include monomers having an allyl group as a functional group involved in a photocuring reaction (photopolymerization reaction). Examples of allyl-based monomers include allyl ethers (allyl ethers of monohydric alcohols, etc.).

[0031] Examples of the oligomer include oligomers that are cured or polymerized by the action of radicals, cations, or anions generated by light irradiation. The weight-average molecular weight of the oligomer is, for example, 8,000 or more, and may be 10,000 or more. The weight-average molecular weight of the oligomer is, for example, 40,000 or less, and may be 30,000 or less. The weight-average molecular weight can be measured using gel permeation chromatography (GPC) or pyrolysis (Py)-GC / MS (a gas chromatograph-mass spectrometer equipped with a pyrolyzer).

[0032] The oligomer has a functional group that participates in a photocuring reaction (photopolymerization reaction). Examples of such functional groups include a (meth)acryloyl group, a vinyl group, an allyl group, and a dienyl group. Among these, from the viewpoint of further improving water resistance, it is preferable to include a (meth)acrylate-based oligomer having a (meth)acryloyl group. In the present disclosure, an acrylate-based oligomer having an acryloyl group and a methacrylate-based oligomer having a methacryloyl group may be referred to as a (meth)acrylate-based oligomer.

[0033] Photopolymerization initiators are activated by the action of light (e.g., ultraviolet light) to initiate curing (polymerization) of reactive monomers. Examples of photopolymerization initiators include radical polymerization initiators that generate radicals by the action of light (ultraviolet light), and cation generators that generate acids (or cations) by the action of light (ultraviolet light). One type of photopolymerization initiator may be used alone, or two or more types may be used in combination. Examples of radical polymerization initiators include alkylphenone-based photopolymerization initiators and acylphosphine oxide-based photopolymerization initiators.

[0034] Examples of alkylphenone-based photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and the like.

[0035] Examples of acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide, etc. These photopolymerization initiators are merely examples and are not limited to these.

[0036] Examples of organic solvents include alcohols, ethers, and ketones. These may be used alone or in combination. The photosensitive resin composition may contain any optional components in addition to the above-mentioned components. Examples of such components include colorants, antioxidants, antifoaming agents, fillers, and stabilizers.

[0037] The monomer preferably contains a (meth)acrylate monomer from the viewpoint of facilitating penetration of the monomer into the waterproof paper 11. The number of functional groups of the (meth)acrylate monomer is not particularly limited.

[0038] If the photocured resin layer 12 and the pigment-containing layer 11b of the waterproof paper 11 are in direct contact, the resin components that make up the photocured resin layer 12 can smoothly penetrate into the waterproof paper 11. Examples of the resin components that can penetrate include monomers contained in the photosensitive resin composition before the photocured resin layer is cured. By penetrating such a resin component and forming a resin component-impregnated layer in the pigment-containing layer 11b of the waterproof paper 11, the water resistance of the waterproof paper 11 and the adhesive strength between the waterproof paper 11 and the photocured resin layer 12 can be improved. The waterproof paper 11 may contain this monomer or a polymer obtained by polymerizing this monomer.

[0039] FIG. 2 shows a schematic diagram of the internal structure of the pigment-containing layer 11b of the waterproof paper 11 in the decorative sheet 10. The photocured resin layer 12 is formed by applying a photosensitive resin composition to the surface of the pigment-containing layer 11b and then irradiating the layer with light. When the photosensitive resin composition is applied to the surface of the pigment-containing layer 11b, resin components 63, such as monomers contained in the photosensitive resin composition, penetrate into the pigment-containing layer 11b. The monomers contained in this resin component 63 may or may not polymerize upon light irradiation. Thus, the pigment-containing layer 11b of the waterproof paper 11 contains resin components, such as monomers and / or their polymers. The pigment-containing layer 11b may contain only a portion of the resin component, or it may have a concentration gradient where the concentration of the resin component increases toward the photocured resin layer 12. This ensures sufficient adhesion to the photocured resin layer 12 while also providing sufficient strength at the boundary between the portion containing the resin component derived from the photosensitive resin composition and the portion not containing the resin component.

[0040] It is believed that the permeated resin component 63 becomes entangled with, for example, the pigment 61 and other components, forming a network within the pigment-containing layer 11b. This improves the water resistance of the pigment-containing layer 11b. Furthermore, the resin component 63 that permeates the pigment-containing layer 11b also bonds with the resin component contained in the photocured resin layer 12. This improves the adhesive strength between the waterproof paper 11 and the photocured resin layer 12.

[0041] The molecular weight of the monomer contained in the photosensitive resin composition is preferably 500 or less, more preferably 400 or less, and even more preferably 300 or less. This allows the monomer to easily penetrate the waterproof paper 11, thereby sufficiently improving water resistance. The molecular weight of the monomer may be, for example, 100 or more.

[0042] The thickness of the photocurable resin layer 12 is preferably 2 to 10 μm, and more preferably 3 to 5 μm, which allows for both ease of folding and durability against moisture to be achieved at a sufficiently high level.

[0043] The adhesive layer 14 functions to bond the photocurable resin layer 12 and the base layer 16 together. Examples of adhesives contained in the adhesive layer 14 include polyvinyl alcohol-based adhesives, urethane-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 2 to 10 μm, and more preferably 4 to 8 μm. This allows for a sufficiently high level of both ease of bending and durability against moisture.

[0044] It is preferable to provide an ink layer partially between the waterproof paper 11 and the photocurable resin layer 12. This can improve the design. Even if an ink layer is provided partially between the waterproof paper 11 and the photocurable resin layer 12, the waterproof paper 11 and the photocurable resin layer 12 are still bonded with high adhesive strength in other parts between the waterproof paper 11 and the photocurable resin layer 12. Therefore, even if an ink layer is provided partially between the waterproof paper 11 and the photocurable resin layer 12, good adhesiveness can be maintained.

[0045] The substrate layer 16 may be a resin film. Examples of resin films include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyolefin films such as polyethylene and polypropylene; polystyrene films; polyamide films such as 66-nylon; polycarbonate films; and engineering plastic films such as polyacrylonitrile films and polyimide films. The surface of the substrate layer 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 substrate layer 16 is not particularly limited and may be, for example, 3 to 50 μm or 6 to 30 μm.

[0046] 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, for example, 10 to 2000 nm, and preferably 10 to 100 nm. This allows the decorative sheet 10, which has excellent decorative properties due to its metallic luster, to be produced at low cost.

[0047] A metallized film or metal foil laminated film in which the base layer 16 and metal film 18 are integrated may also be used. 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.

[0048] An example of a method for manufacturing the decorative sheet 10 will be described. A photosensitive resin composition is coated on the surface of the waterproof paper 11 on the side of the pigment-containing layer 11b. The surface of the coating layer of the photosensitive resin composition is then irradiated with light (ultraviolet rays) to photopolymerize the reactive monomers and reactive oligomers. The light (ultraviolet rays) is irradiated with sufficient intensity and for sufficient time to form a photocured resin layer. This forms a photocured resin layer 12 on one side of the waterproof paper 11.

[0049] An adhesive is applied to one side of the photocurable resin layer 12, and the photocurable resin layer 12 and a metal vapor deposition film or a metal foil laminated film are bonded together via the adhesive, thereby producing the decorative sheet 10.

[0050] The decorative sheet 10 can maintain sufficient durability even when in contact with moisture. Therefore, it can be suitably used, for example, as a sheet material for packaging boxes for packaging impregnated objects impregnated with moisture, aqueous solutions, emulsions, etc. The decorative sheet 10 may be a paper pattern (backing) having ruled lines on at least one of the surfaces 10A and 10B, which serve as starting points for folding. The ruled lines may be grooves (recesses), or perforated through-holes may be formed.

[0051] To ensure smooth folding and high rigidity when the packaging box is formed, the thickness of the decorative sheet 10 is preferably 0.3 to 0.5 mm, and more preferably 0.40 to 0.45 mm. 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 excellent aesthetic appeal because it has the metal film 18 on the outer surface. Furthermore, the inclusion of the waterproof paper 11 reduces the amount of plastic waste, thereby helping to conserve resources.

[0052] The Edgewick value of the decorative sheet 10 when immersed in water at 23°C for 24 hours is preferably 1.5 mg / mm 2The 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. The durability of the decorative sheet 10 tends to depend on the adhesive strength (peel strength) between the waterproof paper 11 and the photocured resin layer 12. This adhesive strength (peel strength) tends to decrease as the amount of water absorbed by the decorative sheet 10 increases. Because the Edge Wick value of the decorative sheet 10 tends to depend on the amount of water absorbed by the waterproof paper 11, the durability of the decorative sheet 10 can be maintained at a high level by reducing the Edge Wick value of the decorative sheet 10.

[0053] The peel strength of the decorative sheet 10 after immersion in water at 20°C for 1 hour is preferably 0.4 [N / 15 mm] or more, more preferably 0.5 [N / 15 mm] or more, and even more preferably 0.6 [N / 15 mm] or more. This peel strength is measured by the method for measuring "peel strength (2)" described in the examples.

[0054] 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.

[0055] A packaging body according to one embodiment comprises a packaging box and an item to be packaged in the packaging box. If the packaging box is made of a decorative sheet 10, at least a portion of the box can be recycled. The packaging box and the packaging body comprising the packaging box may be of a type that has an adhesive sealing surface and a lid label that seals the opening of the box body, which can be repeatedly opened and closed. The decorative sheet 10 may be assembled to form a packaging box. Because the decorative sheet 10 has excellent durability and water resistance, even if the above-mentioned impregnated body is contained therein, peeling of the decorative sheet 10 and damage to the packaging box can be sufficiently prevented.

[0056] 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 include any desired layer. [Example]

[0057] 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.

[0058] [Creating decorative sheets 1] Example 1 Commercially available waterproof paper ("N Mitsubishi Waterproof" manufactured by Mitsubishi Paper Mills, basis weight 350 g / m 2 ) was prepared. As shown in Figure 1, this waterproof paper had a laminated structure consisting of a paper layer 11a containing paper materials such as resin and pulp, and a pigment-containing layer 11b containing a pigment (clay). A photosensitive resin composition was applied onto the pigment-containing layer 11b, and ultraviolet light was irradiated from the coated film side to form a photocured resin layer 12, thereby obtaining a laminate. The photosensitive resin composition used contained 62.2 mass% of acrylate monomer, 28.8 mass% of acrylate oligomer, 0.5 mass% of isopropyl alcohol, 0.2 mass% of ethylene glycol monobutyl ether, and 8.3 mass% of an additive containing a photopolymerization initiator. A metal halide lamp (wavelength: 250 nm to 450 nm) was used as the ultraviolet light source.

[0059] A metallized film with an aluminum vapor deposition layer (thickness: 10-100 nm) formed on a PET film (thickness: 12 μm) and an epoxy adhesive (main agent: AD391-A (trade name), curing agent: AD391-B (trade name), both manufactured by Toyo-Morton Co., Ltd.) were prepared. The epoxy adhesive (application amount: 4.3 g / m) was applied by dry lamination. 2The laminate and the metallized film were bonded together with the PET film and the photocurable resin layer facing each other via a metallized film. The curing time (aging) was set at room temperature for one day. In this way, a decorative sheet with the laminated structure shown in Figure 1 was obtained. The thickness of the decorative sheet was measured using a dial gauge and found to be 440 μm.

[0060] Example 2 Commercially available waterproof paper ("Ecovalley K" manufactured by Nippon Paper Industries Co., Ltd., basis weight: 350 g / m 2 ) was prepared. This waterproof paper had a laminated structure with a resin-coated layer made of resin, a paper layer containing paper material such as resin and pulp, and a pigment-containing layer containing a pigment (clay). A decorative sheet was produced in the same manner as in Example 1, except that this waterproof paper was used. The photosensitive resin composition was coated on top of the pigment-containing layer in the same manner as in Example 1. The thickness of the decorative sheet was measured using a dial gauge and found to be 440 μm.

[0061] (Comparative Example 1) The waterproof paper used in Example 1 was used as Comparative Example 1.

[0062] (Comparative Example 2) Non-waterproof general paper (weight: 310 g / m 2 An epoxy adhesive (application amount: 4.3 g / m) was applied by dry lamination. 2 The PET film and the regular paper were placed opposite each other with a metallized film sandwiched between them. The curing time (aging) was one day at room temperature. In this way, a decorative sheet with a laminated structure consisting of regular paper, an adhesive layer, a base layer (PET film), and a metal film (aluminum vapor-deposited film) was obtained.

[0063] (Comparative Example 3) Except for not providing a photocurable resin layer, a decorative sheet was produced in the same manner as in Example 1. This decorative sheet had a layered structure consisting of waterproof paper, an adhesive layer, a substrate layer (PET film), and a metal film (aluminum vapor deposition film).

[0064] Comparative Example 4 The waterproof paper used in Example 2 was used as Comparative Example 4.

[0065] [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 the mass of the test samples was measured. The Edge Wick value was calculated using the following formula from the mass of the test samples before and after immersion in water. The results are shown in Table 1. The Edge Wick value values ​​in Table 1 are expressed in units of mg / mm 2 " 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)

[0066] [Measurement of peel adhesive strength (1)] After measuring the Edge Wick value as described above, decorative sheets were removed from the test samples, and the peel bond strength of each decorative sheet was measured in accordance with JIS K 6854-1:1999. The peel bond strength of decorative sheets that had not undergone the Edge Wick test was measured in the same way (without immersion). The specific procedure for measuring peel bond strength was as follows: After peeling between the layers at the edge (between the waterproof paper and the photocurable resin layer or adhesive layer), the peel bond strength between the layers was measured using a tensile tester at an angle of 180°, a pulling rate of 300 mm / min, and a temperature of 20°C. This peel bond strength was defined as the peel bond strength after the Edge Wick test. The measurement results are shown in Table 1. The numerical values ​​for peel bond strength (1) in Table 1 are in "N / 15 mm."

[0067] [Measurement of peel adhesive strength (2)] The decorative sheets obtained in each example and comparative example were cut to obtain rectangular samples (15 mm x 100 mm). The samples were immersed in 300 ml of water for 1 hour. After the samples were removed from the water and approximately 10 minutes had passed, the peel bond strength (2) of each sample was measured using the same procedure as in "Measurement of peel bond strength (1)." This peel bond strength was defined as the peel bond strength after the hot water immersion test. The measurement results are shown in Table 1. The numerical values ​​for peel bond strength (2) in Table 1 are in "N / 15 mm."

[0068] [Measurement of peel adhesive strength (3)] The decorative sheets obtained in each Example and Comparative Example 3 were cut to obtain rectangular samples (15 mm x 100 mm). The samples were immersed in 300 ml of lotion for 6 hours. The lotion contained ingredients such as water, glycerin, citric acid, propanediol, BG, phenoxyethanol, and methylparaben. Approximately 10 minutes after the samples were removed from the lotion, the peel bond strength (3) of each sample was measured using the same procedure as in "Measurement of Peel Bond Strength (1)." The measurement results are shown in Table 1. The numerical values ​​for peel bond strength (3) in Table 1 are in "N / 15 mm."

[0069] [Table 1]

[0070] When comparing the Edgewick values ​​of Example 1 and Comparative Examples 1, 2, and 3, which all used the same waterproof paper, Example 1, which had a photocured resin layer, had the lowest Edgewick 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 amount of water absorption could be reduced by providing a photocured resin layer.

[0071] From the results of peel adhesive strength (1), (2), and (3), it was confirmed that Examples 1 and 2 could maintain sufficient durability even when in contact with water. This is thought to be due to the improved adhesive strength between the waterproof paper and the photocured resin layer and the improved water resistance of the waterproof paper. Furthermore, in the case of lotion, Examples 1 and 2 also had high durability, just as in the case of water.

[0072] After measuring the peel adhesive strength (1) for Examples 1 and 2 and Comparative Example 3, IR measurements were performed on the peeled surfaces. Figure 3 shows the IR measurement results for the peeled surface of the decorative sheet in Example 1 that was not subjected to the Edgewick test (absorption spectrum "1" for the peeled surface on the waterproof paper side, and absorption spectrum "2" for the peeled surface on the metal film side). 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 1700 cm -1 On the other hand, there is no absorption peak near 1700 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 absorption peak is thought to be due to the stretching vibration of the carbon-oxygen double bond of resin components such as acrylate monomers. Absorption spectra 1 to 3 in Figure 3 show that the decorative sheet of Example 1 peeled off at the interface between the waterproof paper and the photocurable resin.

[0073] Figure 4 shows the results of IR measurement of the peeled surfaces (the peeled surface on the waterproof paper side and the peeled surface on the metal film side) of the decorative sheet of Example 2 that was not subjected to the Edgewick test. The symbols 1, 2, and 3 in Figure 4 have the same meanings as in Figure 3. Absorption spectra 1 to 3 in Figure 4 show that the decorative sheet of Example 2 also peeled at the interface between the waterproof paper and the photocurable resin. Furthermore, as in Example 1, both the peeled surface on the waterproof paper side (absorption spectrum 1) and the peeled surface on the metal film side (absorption spectrum 2) showed an absorption spectrum at 1700 cm -1 An absorption peak was detected around

[0074] Figure 5 shows the results of IR measurement of the release surfaces (the release surfaces on the waterproof paper side and the metal film side) of the decorative sheet of Comparative Example 3 that was not subjected to the Edgewick test. Figure 5 also shows the results of IR measurement of the pigment-containing layer side of the waterproof paper used in Example 1 as a control. The symbols 1, 2, and 3 in Figure 5 have the same meanings as in Figure 3. In Figure 5, the release surfaces on the waterproof paper side and the metal film side showed spectra similar to those of the waterproof paper itself. This indicated that the waterproof paper itself (the pigment-containing layer itself) had torn and peeled off in the decorative sheet of Comparative Example 1. In the decorative sheet of Comparative Example 3, no peaks derived from the resin component of the photocured resin layer were detected on the release surfaces of either the waterproof paper side or the metal film side.

[0075] According to the IR measurement results described above, in the decorative sheets of Examples 1 and 2, peaks derived from the resin components of the photocured resin layer were detected even on the release surface of the waterproof paper, confirming that resin components such as acrylate monomers had penetrated into the waterproof paper (pigment-containing layer). It is believed that the inclusion of resin components derived from the photosensitive resin composition in the waterproof paper improved the adhesive strength between the waterproof paper and the photocured resin layer and inhibited the penetration of water (lotion), thereby improving the water resistance of the waterproof paper (pigment-containing layer). On the other hand, in the decorative sheet of Comparative Example 3, resin components such as acrylate monomers had not penetrated into the waterproof paper, which is believed to be why the adhesive strength between the waterproof paper and the photocured resin layer was low and why water (lotion) was more likely to penetrate into the waterproof paper.

[0076] After immersion in water for 6 hours, the peel adhesive strength (1) of the decorative sheet of Example 1 was measured. IR measurements were carried out on the peeled surface of the waterproof paper side and the peeled surface of the metal film side. -1 No absorption peak was detected near this point. This confirms that the resin component, such as acrylate monomer, is impregnated not in the entire pigment-containing layer but in only a portion of the photocured resin layer, that the portion containing the resin component maintained high water resistance even after immersion in water for 6 hours, and that the adhesive strength between the pigment-containing layer and the photocured resin layer remained sufficiently high even after immersion in water for 6 hours. [Industrial Applicability]

[0077] According to the present disclosure, it is possible to provide a decorative sheet that can maintain sufficient durability even when it comes into contact with moisture, and a packaging box and a package that can maintain sufficient durability even when packaging a packaged item that contains moisture. [Explanation of symbols]

[0078] 10...decorative sheet, 10A, 10B...surface, 11...water-resistant paper, 11a...paper layer, 11b...pigment-containing layer, 12...photocurable resin layer, 14...adhesive layer, 16...base material layer, 18...metal film, 61...pigment, 63...resin component.

Claims

1. A waterproof sheet, a photocurable resin layer, an adhesive layer, a substrate layer, and a metal film are provided in this order; The decorative sheet has the waterproof paper and the photocured resin layer in direct contact with each other.

2. The decorative sheet described in Claim 1, wherein the waterproof paper contains a resin component that constitutes the photocured resin layer.

3. 3. The decorative sheet according to claim 1, wherein the waterproof paper has a pigment-containing layer, and the resin component constituting the photocured resin layer permeates the pigment-containing layer.

4. 4. The decorative sheet according to claim 1, wherein the photocurable resin layer is made of a UV-cured resin material containing a (meth)acrylic resin.

5. 5. The decorative sheet according to claim 4, wherein the waterproof paper contains a (meth)acrylate monomer and / or a polymer thereof.

6. 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 5, wherein:

7. The decorative sheet according to any one of claims 1 to 6, having ruled lines including recesses or through holes on at least one surface.

8. The decorative sheet according to any one of claims 1 to 7, wherein an ink layer is provided in a portion between the waterproof paper and the photocured resin layer, and the waterproof paper and the photocured resin layer are in direct contact with each other in another portion between the waterproof paper and the photocured resin layer.

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

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

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