Decorative sheet and decorative board

Abstract

This decorative sheet comprises a base paper layer, a thermoplastic resin layer provided on the upper side of the base paper layer, and a picture pattern layer provided on the upper side of the thermoplastic resin layer, the peel strength of the base paper layer being 150 gf or greater. This decorative board comprises a decorative sheet and a base material provided on the lower side of the decorative sheet.

Description

Decorative sheets and boards

[0001] The present invention relates to a decorative sheet and a decorative board. This application claims priority to Japanese Patent Application No. 2024-107685 filed on July 3, 2024, and Japanese Patent Application No. 2024-210043 filed on December 3, 2024, the contents of which are incorporated herein by reference.

[0002] Conventionally, decorative sheets have been used as surface materials for furniture and residential building materials. For example, decorative sheets have a base paper layer with a thermoplastic resin layer laminated on one side thereof to provide functions such as water resistance and oil resistance. Furthermore, decorative sheets often include a base paper layer and a picture / pattern layer laminated on one side thereof. The picture / pattern layer imparts a design to the decorative sheet through a picture. Furthermore, the picture / pattern layer is formed by printing on one side of the base paper layer.

[0003] A decorative sheet having a base paper layer, a thermoplastic resin layer, and a picture pattern layer is the decorative paper described in Patent Document 1. The decorative paper described in Patent Document 1 is a decorative paper in which a thermoplastic resin layer and a picture layer (picture pattern layer) are laminated in this order on one side of the base paper layer.

[0004] Japanese Patent Application Publication No. 2020-75442

[0005] However, in decorative sheets in which a thermoplastic resin layer is laminated on one side of a base paper layer, such as the decorative paper described in Patent Document 1, if the peel strength of the base paper layer is insufficient, the adhesion between the base paper layer and the thermoplastic resin layer may decrease. For this reason, there has been a demand for decorative sheets and decorative boards that improve the adhesion between the base paper layer and the thermoplastic resin layer provided on one side of the base paper layer.

[0006] Furthermore, decorative sheets that have a thermoplastic resin layer between the base paper layer and the picture pattern layer may curl when the picture pattern layer is printed due to differences in the thermal shrinkage rates between the base paper layer and the thermoplastic resin layer. Furthermore, if the strength of the thermoplastic resin layer is insufficient, the surface strength of the decorative sheet may be poor, and when an external force is applied to the surface of the decorative sheet, dents may occur on the surface of the decorative sheet, or peeling may occur between the base paper layer and the thermoplastic resin layer. Therefore, there has been a demand for decorative sheets and decorative boards that suppress curling and have improved surface strength.

[0007] In light of the above circumstances, an object of the present invention is to provide a decorative sheet and decorative board with improved strength.

[0008] In order to solve the above problems, the present invention proposes the following means: [1] A decorative sheet comprising a base paper layer, a thermoplastic resin layer provided on the upper side of the base paper layer, and a picture pattern layer provided on the upper side of the thermoplastic resin layer, wherein the peel strength of the base paper layer is 150 gf or more.

[0009] [2] The decorative sheet according to [1], wherein the peel strength between the base paper layer and the thermoplastic resin layer is 9.0 N or more.

[0010] [3] The base paper layer has a basis weight of 20 g / m ２ More than 100g / m ２ The decorative sheet according to [1] or [2] below.

[0011] [4] The decorative sheet according to any one of [1] to [3], wherein the thickness of the thermoplastic resin layer is 10 μm or more and 20% to 80% of the thickness of the base paper layer.

[0012] [5] The decorative sheet according to any one of [1] to [3], wherein the thermoplastic resin layer has a thickness of 20% to 80% of the thickness of the base paper layer and 10 μm or more, and contains a homopolypropylene resin.

[0013] [6] The decorative sheet according to any one of [1] to [5], further comprising a base colored layer provided on the upper side of the thermoplastic resin layer and on the lower side of the picture pattern layer.

[0014] [7] The decorative sheet according to [6], wherein the base colored layer contains an isocyanate curing agent, and the thermoplastic resin layer is subjected to a corona treatment on the upper surface on which the base colored layer is provided.

[0015] [8] The decorative sheet according to any one of [1] to [7], comprising: a first surface protective layer provided on the upper side of the picture and pattern layer; and a second surface protective layer provided on the upper side of the first surface protective layer in a position that is in harmony with the pattern of the picture and pattern layer and that has a gloss different from that of the first surface protective layer, wherein the first surface protective layer and the second surface protective layer contain a urethane-based resin.

[0016] [9] A decorative board comprising the decorative sheet according to any one of [1] to [8] and a substrate provided below the decorative sheet.

[0017] In one aspect, the present invention has the following embodiment: [A1] The decorative sheet of the present invention comprises a base paper layer, a thermoplastic resin layer provided on the upper side of the base paper layer, and a picture pattern layer provided on the upper side of the thermoplastic resin layer, and the peel strength of the base paper layer is 150 gf or more.

[0018] [A2] In the decorative sheet described in [A1], the interlaminar peel strength between the base paper layer and the thermoplastic resin layer is 9.0 N or more.

[0019] [A3] In the decorative sheet according to [A1] or [A2], the base paper layer has a basis weight of 20 g / m ２ More than 100g / m ２ The following is the result.

[0020] [A4] In the decorative sheet according to any one of [A1] to [A3], the thickness of the thermoplastic resin layer is 10 μm or more, and is 20% or more and 80% or less of the thickness of the base paper layer.

[0021] [A5] The decorative sheet according to any one of [A1] to [A4] further comprises a base colored layer provided on the upper side of the thermoplastic resin layer and on the lower side of the picture pattern layer.

[0022] [A6] The decorative board of the present invention comprises the decorative sheet according to any one of [A1] to [A5] and a substrate provided below the decorative sheet.

[0023] In another aspect, the present invention has the following embodiment: [B1] The decorative sheet of the present invention comprises a base paper layer, a thermoplastic resin layer provided on the upper side of the base paper layer, and a picture pattern layer provided on the upper side of the thermoplastic resin layer, wherein the thermoplastic resin layer has a thickness of 20% to 80% of the thickness of the base paper layer and 10 μm or more, and contains a homopolypropylene resin.

[0024] [B2] The decorative sheet described in [B1] may have a base colored layer containing an isocyanate curing agent provided between the thermoplastic resin layer and the picture pattern layer, and the thermoplastic resin layer has been subjected to corona treatment on the upper surface on which the base colored layer is provided.

[0025] [B3] The decorative sheet described in [B1] or [B2] may comprise a first surface protective layer provided above the picture and pattern layer, and a second surface protective layer provided above the first surface protective layer and in a position that is in harmony with the picture of the picture and pattern layer, and having a gloss different from that of the first surface protective layer, wherein the first surface protective layer and the second surface protective layer contain a urethane-based resin.

[0026] [B4] The decorative board of the present invention comprises the decorative sheet according to any one of [B1] to [B3] and a substrate adhered to the underside of the decorative sheet.

[0027] According to the present invention, it is possible to provide a decorative sheet and a decorative board with improved strength.

[0028] 1 is a cross-sectional view schematically showing a decorative board according to a first embodiment; FIG. 2 is a cross-sectional view schematically showing a decorative board according to a second embodiment;

[0029] A first embodiment of the present invention will be described with reference to the drawings.

[0030] FIG. 1 is a cross-sectional view that schematically shows a decorative board 100 according to this embodiment.

[0031] In this embodiment, as shown in Figure 1, the thickness direction of the decorative board 100 is defined as the "vertical direction V", the side of the decorative board 100 on which the base material 20 is provided is defined as the "lower side LO" in the vertical direction V, and the side opposite the lower side LO is defined as the "upper side UP" in the vertical direction V.

[0032] The decorative board 100 comprises a decorative sheet 10 and a substrate 20 .

[0033] The substrate 20 is a layer provided on the lower side LO of the decorative board 100. The substrate 20 is adhered to the lower side LO of the decorative sheet 10. As the substrate 20, particle board, medium density fiberboard (MDF), or the like can be used.

[0034] The substrate 20 may be a metal plate-like member such as aluminum or stainless steel, or a composite plate in which metal such as aluminum is attached to both sides of a core material made of resin such as polyethylene.

[0035] The decorative sheet 10 comprises a base paper layer 1, a thermoplastic resin layer 2, a base colored layer 3, a picture pattern layer 4, and a surface protective layer 7.

[0036] The base paper layer 1 is a layer provided on the lower side LO of the decorative sheet 10. A substrate 20 is adhered to the surface of the lower side LO of the base paper layer 1 (lower surface 1b).

[0037] The base paper layer 1 may be a thin paper such as reinforced paper or printing paper, or a fibrous sheet such as titanium paper.

[0038] The base paper layer 1 has a peel strength of 150 gf or more. In this embodiment, the peel strength refers to the peel strength measured by a T-peel test in accordance with JIS K 6854-3. That is, the base paper layer 1 has a T-peel strength of 150 gf or more.

[0039] The basis weight of the base paper layer 1 is 20 g / m ２ More than 100g / m ２ The following is preferable: This allows the base paper layer 1 to have stiffness, making the decorative sheet 10 less likely to wrinkle and preventing the decorative sheet 10 from curling.

[0040] The thermoplastic resin layer 2 is a layer provided on one surface of the base paper layer 1. In this embodiment, the thermoplastic resin layer 2 is provided on the surface of the upper side UP of the base paper layer 1 (upper surface 1s).

[0041] An olefin-based resin such as polyethylene or polypropylene can be used as the thermoplastic resin layer 2. By using an olefin-based resin as the thermoplastic resin layer 2, the scratch resistance of the decorative sheet 10 can be improved.

[0042] It is preferable to use a moisture-proof material for the thermoplastic resin layer 2. By using a moisture-proof thermoplastic resin layer 2, it is possible to prevent water vapor from passing from the surface 10s of the decorative sheet 10 to the base paper layer 1 and substrate 20, thereby forming a decorative sheet 10 and decorative board 100 with excellent water resistance. The surface 10s of the decorative sheet 10 refers to the upper side UP of the decorative sheet 10, as shown in Figure 1.

[0043] The thickness of the thermoplastic resin layer 2 is preferably 10 μm or more and 20% to 80% of the thickness of the base paper layer 1 .

[0044] By making the thickness of the thermoplastic resin layer 2 10 μm or more and making it 20% or more of the thickness of the base paper layer 1, a sufficient moisture-proof effect can be obtained.

[0045] Furthermore, by making the thickness of the thermoplastic resin layer 2 80% or less of the thickness of the base paper layer 1, curling of the decorative sheet 10 can be prevented.

[0046] The thermoplastic resin layer 2 can be formed by melt extrusion molding, dry lamination, wet lamination, non-solvent lamination, wax lamination, or the like.

[0047] The interlayer peel strength between the base paper layer 1 and the thermoplastic resin layer 2 is preferably 9.0 N or more. Here, the interlayer peel strength between the base paper layer 1 and the thermoplastic resin layer 2 refers to the T-peel strength between the upper surface 1s of the base paper layer 1 and the lower surface 2b (the surface of the lower side LO) of the thermoplastic resin layer 2.

[0048] Corona treatment may be performed on the surface (upper surface 2s) of the upper side UP of the thermoplastic resin layer 2. By performing corona treatment on the upper surface 2s of the thermoplastic resin layer 2, polar groups are generated and wettability is improved, thereby improving the adhesion between the thermoplastic resin layer 2 and the undercoat colored layer 3.

[0049] The undercoat colored layer 3 is a layer provided on the upper side UP of the thermoplastic resin layer 2. The undercoat colored layer 3 is formed on the upper surface 2s of the thermoplastic resin layer 2 by printing, for example.

[0050] The base coloring layer 3 is a layer that provides base coloring for the picture pattern layer 4 and concealing properties to prevent the color and texture of the thermoplastic resin layer 2, base paper layer 1, and substrate 20 from penetrating through to the surface 10s of the decorative sheet 10.

[0051] For the base color layer 3, for example, a two-component curing urethane resin ink containing an isocyanate curing agent can be used.

[0052] Since urethane resin has a polar group, it has excellent adhesion. Therefore, by forming a base colored layer 3 containing a urethane resin on the upper surface 2s of the thermoplastic resin layer 2 that has been subjected to corona treatment, high adhesion can be achieved between the thermoplastic resin layer 2 and the base colored layer 3.

[0053] The base colored layer 3 can be formed by a known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or ink jet printing.

[0054] The picture pattern layer 4 is a layer provided on the upper side UP of the base colored layer 3, and is a layer formed by printing a picture pattern such as wood grain, stone grain, or sand grain.

[0055] A known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or inkjet printing can be used to form the picture pattern layer 4. Also, a known printing ink suitable for the printing method to be used can be used for the picture pattern layer 4.

[0056] The surface protective layer 7 is a layer provided on the upper side UP of the picture and pattern layer 4. The surface protective layer 7 has a first surface protective layer 5 formed on the upper side UP of the picture and pattern layer 4 and a second surface protective layer 6 formed on the upper side UP of the first surface protective layer 5.

[0057] The first surface protective layer 5 is preferably made of a transparent or semi-transparent material that allows the design of the design pattern layer 4 to be seen through.

[0058] The first surface protective layer 5 may be made of a thermosetting resin having a urethane bond or an ionizing radiation curable resin such as an acrylic resin.

[0059] A known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or inkjet printing can be used as a method for forming the first surface protective layer 5. The first surface protective layer 5 may also be formed using a known coating device.

[0060] The second surface protective layer 6 is preferably made of a transparent or semi-transparent material that allows the design of the design pattern layer 4 to be seen through the first surface protective layer 5 .

[0061] The second surface protective layer 6 may be made of a thermosetting resin having a urethane bond or an ionizing radiation curable resin such as an acrylic resin.

[0062] The second surface protective layer 6 can be formed by a known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or inkjet printing. The second surface protective layer 6 may also be formed using a known coating device.

[0063] The first surface protective layer 5 and the second surface protective layer 6 have different glosses. One method for imparting a difference in gloss between the first surface protective layer 5 and the second surface protective layer 6 is to add a matting agent to the first surface protective layer 5.

[0064] By adding a matting agent to the first surface protective layer 5, the gloss of the first surface protective layer 5 can be made lower than the gloss of the second surface protective layer 6. In other words, the first surface protective layer 5 functions as a matting layer.

[0065] Furthermore, different amounts of matting agent may be added to the first surface protective layer 5 and the second surface protective layer 6 to the extent that a difference in gloss can be imparted between the first surface protective layer 5 and the second surface protective layer 6 .

[0066] As the matting agent, for example, fine particles made of inorganic substances such as silica, alumina (α-alumina, etc.), calcium carbonate, barium sulfate, kaolinite, alumina silicate, etc., and organic substances such as polycarbonate, nylon, urethane resin, acrylic resin, styrene resin, silicone resin, etc. can be used.

[0067] In addition, a difference in gloss may be imparted between the first surface protective layer 5 and the second surface protective layer 6 by forming the second surface protective layer 6 from a resin material having a higher gloss than the resin material used for the first surface protective layer 5.

[0068] The difference in gloss between the first surface protective layer 5 and the second surface protective layer 6 can be used to create a visual three-dimensional effect by utilizing an optical illusion of the human eye.

[0069] 1, the second surface protective layer 6 may be partially provided on the upper side UP of the first surface protective layer 5. Alternatively, the second surface protective layer 6 may be provided in a position that is in harmony with the pattern of the picture pattern layer 4.

[0070] For example, if the design layer 4 has a wood grain pattern, by forming the second surface protective layer 6 in a position that is in sync with the vessel portion of the wood grain pattern, the difference in gloss between the first surface protective layer 5 and the second surface protective layer 6 can give the vessel portion a visual three-dimensional effect, thereby providing a decorative sheet 10 and decorative board 100 with a wood grain pattern that more closely resembles the appearance of natural wood.

[0071] As described above, the peel strength of the base paper layer 1 is 150 gf or more. By making the peel strength of the base paper layer 1 150 gf or more, the adhesion between the base paper layer 1 and the thermoplastic resin layer 2 can be improved.

[0072] For example, when the thermoplastic resin layer 2 is formed on the upper surface 1s of the base paper layer 1 by melt extrusion molding, the thermoplastic resin layer 2 is formed in a state where part of the resin material forming the thermoplastic resin layer 2 has soaked into the base paper layer 1.

[0073] If the peel strength of the base paper layer is less than 150 gf, when a force is applied to the decorative sheet in a direction that causes the upper surface of the base paper layer and the lower surface of the thermoplastic resin layer to peel off, the upper surface of the base paper layer may peel off together with the thermoplastic resin layer while remaining in close contact with the thermoplastic resin layer.

[0074] That is, if the peel strength of the base paper layer is less than 150 gf, peeling may occur between the base paper layers near the upper surface of the base paper layer.

[0075] In the decorative sheet 10 and decorative board 100 of this embodiment, by making the peel strength of the base paper layer 1 150 gf or more, even when a force is applied in a direction that causes the upper surface 1s of the base paper layer 1 to peel from the lower surface 2b of the thermoplastic resin layer 2, peeling between the layers of the base paper layer 1 can be suppressed, and the adhesion between the base paper layer 1 and the thermoplastic resin layer 2 can be sufficiently maintained.

[0076] For example, by using a base paper layer 1 with a peel strength of 150 gf or more, a decorative sheet 10 and a decorative board 100 can be realized in which the peel strength between the base paper layer 1 and the thermoplastic resin layer 2 is 9.0 N or more, and a decorative sheet 10 and a decorative board 100 can be realized in which the adhesion between the base paper layer 1 and the thermoplastic resin layer 2 is improved compared to conventional decorative sheets and decorative boards.

[0077] The decorative sheet 10 of this embodiment comprises a base paper layer 1, a thermoplastic resin layer 2 provided on the upper side UP of the base paper layer 1, and a picture pattern layer 4 provided on the upper side UP of the thermoplastic resin layer 2, and the peel strength of the base paper layer 1 is 150 gf or more.

[0078] The decorative board 100 of this embodiment comprises a decorative sheet 10 and a substrate 20 provided on the lower side LO of the decorative sheet 10 .

[0079] According to the decorative sheet 10 and decorative board 100 of this embodiment, a decorative sheet 10 and decorative board 100 can be provided that have improved adhesion between the base paper layer 1 and the thermoplastic resin layer 2 provided on one side of the base paper layer 1.

[0080] Although the first embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the present invention. Furthermore, the components shown in the above-described embodiment and the modified examples shown below can be configured by appropriately combining them.

[0081] (Modification 1) In the above embodiment, the decorative sheet 10 includes the base colored layer 3, but the form of the decorative sheet is not limited to this. The decorative sheet does not have to include the base colored layer.

[0082] In the above embodiment, the base coloring layer 3 is a layer that provides base coloring for the picture pattern layer 4 and concealing properties to prevent the color and texture of the thermoplastic resin layer 2, base paper layer 1, and substrate 20 from penetrating through to the surface 10s of the decorative sheet 10.

[0083] If sufficient base coloring and hiding power can be obtained without providing a base coloring layer, the decorative sheet does not need to be provided with a base coloring layer.

[0084] When the decorative sheet does not include a base color layer, the picture design layer is provided on the upper surface of the thermoplastic resin layer.

[0085] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0086] (Example 1) Base paper layer 1: Basis weight 20 g / m ２ A reinforced inter-paper paper having a T-peel strength of 180 gf was prepared.

[0087] A polypropylene (PP) resin having a thickness of 16 μm was provided by melt extrusion molding on the upper surface 1 s of the base paper layer 1 to form a thermoplastic resin layer 2. The upper surface 2 s of the thermoplastic resin layer 2 was subjected to corona treatment.

[0088] A urethane ink (PCNT manufactured by Toyo Ink Co., Ltd.) containing an isocyanate curing agent was printed by gravure printing on the upper surface 2s of the thermoplastic resin layer 2 that had been subjected to corona treatment, to form a base colored layer 3.

[0089] A urethane ink (PCNT manufactured by Toyo Ink Co., Ltd.) was printed by gravure printing on the upper surface UP of the base colored layer 3 to form a picture pattern layer 4 having a wood grain pattern.

[0090] A urethane resin was applied to the upper surface UP of the picture pattern layer 4 as a first surface protective layer 5 .

[0091] A urethane-based gloss resin was applied to the upper surface UP of the first surface protective layer 5 as a second surface protective layer 6. The second surface protective layer 6 was applied using a die that matched the vessels in the wood grain pattern of the picture design layer 4.

[0092] After applying the second surface protective layer 6, the product was cured at 60°C for 96 hours to cause the curing agent added to the surface protective layer 7 (first surface protective layer 5 and second surface protective layer 6) to react and harden the surface protective layer 7, thereby obtaining the decorative sheet 10 of Example 1.

[0093] (Example 2) Base paper layer 1: 30 g / m ２ A decorative sheet 10 of Example 2 was obtained in the same manner as in Example 1, except that a reinforced inter-paper paper having a T-peel strength of 180 gf was used.

[0094] (Example 3) Base paper layer 1: basis weight 40 g / m ２ A decorative sheet 10 of Example 3 was obtained in the same manner as in Example 1, except that a printing paper having a T-peel strength of 150 gf was used.

[0095] (Example 4) Base paper layer 1: basis weight 45 g / m ２ A decorative sheet 10 of Example 4 was obtained in the same manner as in Example 1, except that a printing paper having a T-peel strength of 185 gf was used.

[0096] (Example 5) Base paper layer 1: 50 g / m ２ A decorative sheet 10 of Example 5 was obtained in the same manner as in Example 1, except that a printing paper having a T-peel strength of 200 gf was used.

[0097] (Comparative Example 1) Base paper layer: 30 g / m ２ A decorative sheet of Comparative Example 1 was obtained in the same manner as in Example 1, except that a reinforced inter-paper paper having a T-peel strength of 140 gf was used.

[0098] (Test 1) A peel strength test was carried out on the decorative sheets of Examples 1 to 5 and Comparative Example 1. In the peel strength test, a substrate such as MDF was attached to the upper surface of the decorative sheet with double-sided tape, and the decorative sheet was reinforced with 25 mm wide cellophane tape to prevent tearing, and the T-peel strength of the decorative sheet was measured with a load cell type tensile tester.

[0099] The T-peel strength measured in the peel strength test is the peel strength between the base paper layer and the thermoplastic resin layer. In the peel strength test, the width of the test piece was 25 mm, and the peel speed was 200 mm / min.

[0100] In addition, in the peel strength test, the peeled surface between the peeled base paper layer and the thermoplastic resin layer was also observed.

[0101] (Test 2) A crosshatch tape (crosscut) test was carried out on the decorative sheets of Examples 1 to 5 and Comparative Example 1. The crosshatch tape test was carried out in accordance with JIS K 5600.

[0102] Specifically, in a decorative panel made by attaching a base material such as MDF to the underside of a decorative sheet using a vinyl acetate adhesive or the like, 10 x 10 1mm square grid cuts were made on the surface of the decorative sheet, and cellophane tape manufactured by Nichiban Co., Ltd. was attached to the cut areas and peeled off at an angle of approximately 60 degrees to the surface of the decorative sheet.

[0103] Thereafter, the presence or absence of peeled grids on the surface of the decorative sheet was evaluated.

[0104] The evaluation criteria were divided into two stages, with ◯ being considered acceptable: ◯ (Good): No peeling of the grid occurred; × (Poor): Peeling of the grid occurred.

[0105] (Test Results) The results of Test 1 and Test 2 are shown in Table 1. Table 1 also shows the basis weight and T-peel strength of the base paper layer.

[0106] In addition, the column "peeling surface" in Table 1 shows the observation results of the peeling surface between the base paper layer and the thermoplastic resin layer carried out in Test 1.

[0107] In the observation results of the peeled surface shown in Table 1, "between the sheets" indicates that a part of the base paper layer peeled off together with the thermoplastic resin layer, and peeling occurred between the base paper layers.

[0108] Furthermore, the column "Resin layer elongation" in Table 1 indicates whether or not the thermoplastic resin layer elongated, and "Yes" indicates that when the thermoplastic resin layer in close contact with the base paper layer was pulled using a tensile tester, elongation occurred in the thermoplastic resin layer as plastic deformation.

[0109] "None" in "Resin layer elongation" indicates that no elongation as plastic deformation occurred in the thermoplastic resin layer when it was pulled using a tensile tester.

[0110] In addition, in Table 1, for the cases where peeling of the squares occurred in Test 2, the number of peeled squares is also recorded.

[0111] Examples 1 to 5, in which the peel strength of the base paper layer 1 was 150 gf or more, showed good results in Test 2. Furthermore, Examples 1 to 5 had peel strengths of 9.0 N or more measured in Test 1.

[0112] In Test 1, among Examples 1 to 5 and Comparative Example 1, Example 1, which had the highest measured peel strength, and Example 4, which had the second highest measured peel strength after Example 1, experienced elongation of the thermoplastic resin layer 2.

[0113] Comparative Example 1, in which the peel strength of the base paper layer was less than 150 gf, failed Test 2. In Comparative Example 1, 5 of the 100 squares peeled off in Test 2.

[0114] Furthermore, the peel strength of Comparative Example 1 measured in Test 1 was 7.8 N, which was smaller than the peel strength of Example 3, which was 9.0 N and was the smallest among Examples 1 to 5, measured in Test 1.

[0115] In Test 1, in Examples 1 to 5 and Comparative Example 1, peeling occurred between the base paper layers.

[0116]

[0117] A second embodiment of the present invention will be described with reference to the drawings. The decorative board 100 according to this embodiment differs from the first embodiment in that the thermoplastic resin layer 2 is a thermoplastic resin layer 2a containing a homopolypropylene resin, but the basic configuration is the same as that of the first embodiment. Figure 2 is a cross-sectional view schematically showing the decorative board 100 according to this embodiment.

[0118] In this embodiment, as shown in Figure 2, the thickness direction of the decorative board 100 is defined as the "vertical direction V", the side of the decorative board 100 on which the base material 20 is provided is defined as the "lower side LO" in the vertical direction V, and the side opposite the lower side LO is defined as the "upper side UP" in the vertical direction V.

[0119] The decorative board 100 includes a decorative sheet 10 and a substrate 20. The substrate 20 is a layer provided on the lower side LO of the decorative board 100. The substrate 20 is adhered to the lower side LO of the decorative sheet 10. Particle board, medium density fiberboard (MDF), or the like can be used as the substrate 20.

[0120] The substrate 20 may be a metal plate-like member such as aluminum or stainless steel, or a composite plate in which metal such as aluminum is attached to both sides of a core material made of resin such as polyethylene.

[0121] The decorative sheet 10 comprises a base paper layer 1, a thermoplastic resin layer 2a, a base colored layer 3, a picture pattern layer 4, a first surface protective layer 5 (matte layer), and a second surface protective layer 6.

[0122] The base paper layer 1 is a layer provided on the lower side LO of the decorative sheet 10. A substrate 20 is adhered to the surface of the lower side LO of the base paper layer 1. As the base paper layer 1, a thin paper such as reinforced paper or printing paper, or a fibrous sheet such as titanium paper can be used.

[0123] The thermoplastic resin layer 2a is a layer provided on the upper side UP of the base paper layer 1. The thermoplastic resin layer 2a contains homopolypropylene resin. The thermoplastic resin layer 2a may contain only homopolypropylene resin as a resin component. For example, polyethylene resin is often used for the thermoplastic resin layer in conventional decorative sheets. A thermoplastic resin layer 2a containing homopolypropylene resin has superior rigidity compared to when polyethylene resin is used, and therefore can improve the surface strength of the decorative sheet 10. The surface of the decorative sheet 10 refers to the surface of the upper side UP of the decorative sheet 10.

[0124] Furthermore, since the thermoplastic resin layer 2a containing homopolypropylene resin has superior rigidity compared to when polyethylene resin is used, the occurrence of curling of the decorative sheet 10 can be suppressed by the thermoplastic resin layer 2a containing homopolypropylene resin.

[0125] The thermoplastic resin layer 2a has a thickness of 10 μm or more and 20% or more and 80% or less of the thickness of the base paper layer 1. By making the thickness of the thermoplastic resin layer 2a 20% or more and 10 μm or more of the thickness of the base paper layer 1, it is possible to improve the surface strength of the decorative sheet 10. The thermoplastic resin layer 2a of this embodiment contains a homopolypropylene resin and has a thickness of 10 μm or more and 20% or more of the thickness of the base paper layer 1, so that it is possible to impart sufficient surface strength to the decorative sheet 10.

[0126] Furthermore, by making the thickness of the thermoplastic resin layer 2a 80% or less of the thickness of the base paper layer 1, it is possible to suppress curling of the decorative sheet 10. The thermoplastic resin layer 2a of this embodiment contains a homopolypropylene resin, and has a thickness 80% or less of the thickness of the base paper layer 1, which can suitably suppress curling of the decorative sheet 10. Homopolypropylene resin has excellent heat resistance and solvent resistance. Therefore, by using a homopolypropylene resin for the thermoplastic resin layer 2a, it is possible to improve the heat resistance and solvent resistance of the decorative sheet 10.

[0127] The thermoplastic resin layer 2a can be formed by melt extrusion molding, dry lamination, wet lamination, non-solvent lamination, wax lamination, or the like.

[0128] The upper surface 2s of the thermoplastic resin layer 2a may be subjected to a corona treatment to generate polar groups and improve wettability, thereby improving adhesion between the thermoplastic resin layer 2a and the undercoat colored layer 3.

[0129] The base colored layer 3 is a layer provided on the upper side UP of the thermoplastic resin layer 2a. The base colored layer 3 is formed, for example, by printing on the upper surface 2s of the thermoplastic resin layer 2a. The base colored layer 3 can be formed by a known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or inkjet printing.

[0130] For example, a two-component curing urethane resin ink containing an isocyanate curing agent can be used as the base colored layer 3. By providing the base colored layer 3, the hiding power of the decorative sheet 10 can be improved, and the texture and color of the substrate 20 can be prevented from showing through to the surface of the decorative sheet 10.

[0131] The picture pattern layer 4 is a layer provided on the upper side UP of the base colored layer 3, and is formed by printing a pattern such as wood grain, stone grain, or sand grain. The picture pattern layer 4 can be formed by a known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or inkjet printing. The picture pattern layer 4 can be formed using a known printing ink suitable for the printing method used.

[0132] The first surface protective layer 5 is a layer provided on the upper side UP of the picture pattern layer 4. The first surface protective layer 5 is preferably made of a transparent or semi-transparent material that allows the picture of the picture pattern layer 4 to be seen through. As the material of the first surface protective layer 5, for example, a urethane-based resin can be used.

[0133] A known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or inkjet printing can be used as a method for forming the first surface protective layer 5. The first surface protective layer 5 may also be formed using a known coating device.

[0134] The second surface protective layer 6 is a layer provided on the upper side UP of the first surface protective layer 5. The second surface protective layer 6 is preferably made of a transparent or semi-transparent material that allows the design of the design pattern layer 4 to be seen through the first surface protective layer 5. As the material of the second surface protective layer 6, for example, a urethane-based resin can be used.

[0135] The second surface protective layer 6 can be formed by a known printing method such as gravure printing, offset printing, flexographic printing, silk screen printing, or inkjet printing. The second surface protective layer 6 may also be formed using a known coating device.

[0136] When a thermosetting resin having urethane bonds is used for the first surface protective layer 5 and the second surface protective layer 6, the hardness may be inferior compared to, for example, when an ultraviolet-curable resin is used. The decorative sheet 10 of this embodiment includes a thermoplastic resin layer 2a that contains a homopolypropylene resin and has a thickness of 20% or more of the thickness of the base paper layer 1 and 10 μm or more, and therefore can have sufficient surface strength even when the first surface protective layer 5 and the second surface protective layer 6 are formed from a thermosetting resin.

[0137] It is preferable that the first surface protective layer 5 and the second surface protective layer 6 have different glosses. One method for imparting a difference in gloss between the first surface protective layer 5 and the second surface protective layer 6 is to add a matting agent to the first surface protective layer 5. By adding a matting agent to the first surface protective layer 5, the gloss of the first surface protective layer 5 can be made lower than the gloss of the second surface protective layer 6.

[0138] Furthermore, different amounts of matting agent may be added to the first surface protective layer 5 and the second surface protective layer 6 to the extent that a difference in gloss can be imparted between the first surface protective layer 5 and the second surface protective layer 6. The difference in gloss between the first surface protective layer 5 and the second surface protective layer 6 can take advantage of an optical illusion to create a visual sense of three-dimensionality. The second surface protective layer 6 may be made of a gloss resin that has a sufficiently higher gloss than the first surface protective layer 5.

[0139] The second surface protective layer 6 is preferably formed in a position that is in harmony with the pattern of the picture pattern layer 4. For example, if the picture pattern layer 4 has a wood grain pattern, by forming the second surface protective layer 6 in a position that is in harmony with the vessel portion of the wood grain pattern, the difference in gloss between the first surface protective layer 5 and the second surface protective layer 6 can impart a visual three-dimensional effect to the vessel portion, thereby providing a decorative sheet 10 and decorative board 100 with a wood grain pattern that more closely resembles the appearance of natural wood.

[0140] The decorative sheet 10 of this embodiment comprises a base paper layer 1, a thermoplastic resin layer 2a provided on the upper side UP of the base paper layer 1, and a picture pattern layer 4 provided on the upper side UP of the thermoplastic resin layer 2a. The thermoplastic resin layer 2a has a thickness of 20% to 80% of the thickness of the base paper layer 1 and 10 μm or more, and contains a homopolypropylene resin. The decorative board 100 of this embodiment comprises a decorative sheet 10 and a substrate 20 adhered to the lower side LO of the decorative sheet 10.

[0141] The decorative sheet 10 and decorative board 100 of this embodiment can suppress curling and provide a decorative sheet 10 and decorative board 100 with improved surface strength. Furthermore, since the thermoplastic resin layer 2a contains a homopolypropylene resin, the heat resistance and solvent resistance of the decorative sheet 10 and decorative board 100 can be improved.

[0142] Although the second embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the present invention. Furthermore, the components shown in the above-described embodiment and the modified examples shown below can be configured by appropriately combining them.

[0143] (Modification 2-1) In the above embodiment, the decorative sheet 10 includes the base colored layer 3, but the form of the decorative sheet is not limited to this. The decorative sheet does not have to include the base colored layer 3.

[0144] The base coloring layer 3 is a layer that provides base coloring for the picture pattern layer 4 and also provides concealment to prevent the color and texture of the thermoplastic resin layer 2a, base paper layer 1, and substrate 20 from penetrating through to the surface of the decorative sheet 10.

[0145] If sufficient base coloring and hiding properties can be obtained without providing the base coloring layer 3, the decorative sheet does not need to have the base coloring layer 3. If the decorative sheet does not have the base coloring layer 3, the picture pattern layer is provided on the upper surface of the thermoplastic resin layer.

[0146] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0147] (Example 2-1) The base paper layer 1 had a thickness of 26 μm (basis weight 25 g / m ２ ) was prepared. A homopolypropylene resin (homoPP) was applied to the upper surface of the base paper layer 1 by melt extrusion molding to a thickness of 16 μm to form a thermoplastic resin layer 2a. The upper surface 2s of the thermoplastic resin layer 2a was subjected to corona treatment. In Example 2-1, the thickness of the thermoplastic resin layer 2a was 62% of the thickness of the base paper layer 1.

[0148] A urethane ink (PCNT manufactured by Toyo Ink Co., Ltd.) containing an isocyanate curing agent was printed by gravure printing on the upper surface 2s of the corona-treated thermoplastic resin layer 2a to form a base colored layer 3.

[0149] A urethane ink (PCNT manufactured by Toyo Ink Co., Ltd.) was printed on the upper surface UP of the base colored layer 3 to form a picture pattern layer 4 having a wood grain pattern.

[0150] A urethane resin was applied to the upper UP surface of the picture pattern layer 4 as a first surface protective layer 5. A urethane gloss resin was applied to the upper UP surface of the first surface protective layer 5 as a second surface protective layer 6. The second surface protective layer 6 was applied using a die that matched the vessels in the wood grain pattern of the picture pattern layer 4.

[0151] After the second surface protective layer 6 was applied, it was cured at 60°C for 96 hours to react the curing agents added to the first surface protective layer 5 and the second surface protective layer 6, thereby curing the first surface protective layer 5 and the second surface protective layer 6. In this way, the decorative sheet 10 of Example 2-1 was obtained.

[0152] (Example 2-2) The base paper layer 1 had a thickness of 31 μm (basis weight 30 g / m ２ A decorative sheet 10 of Example 2-2 was obtained in the same manner as in Example 2-1, except that a reinforced inter-paper paper of Example 2-1 was used. In Example 2-1, the thickness of the thermoplastic resin layer 2a was 52% of the thickness of the base paper layer 1.

[0153] (Comparative Example 2-1) A base paper layer having a thickness of 35 μm (basis weight 35 g / m ２ A decorative sheet of Comparative Example 2-1 was obtained in the same manner as in Example 2-1, except that a reinforced inter-paper paper of 1000 kJ / cm2 was used and the thickness of the thermoplastic resin layer was 30 μm. In Comparative Example 2-1, the thickness of the thermoplastic resin layer was 86% of the thickness of the base paper layer.

[0154] (Comparative Example 2-2) A base paper layer having a thickness of 31 μm (basis weight 30 g / m ２ A decorative sheet of Comparative Example 2-2 was obtained in the same manner as in Example 2-1, except that a reinforced inter-paper paper of 1000 kJ / cm² was used and a random polypropylene resin (random PP) was used for the thermoplastic resin layer. In Comparative Example 2-2, the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer.

[0155] (Comparative Example 2-3) A base paper layer having a thickness of 31 μm (basis weight 30 g / m ２ A decorative sheet of Comparative Example 2-3 was obtained in the same manner as in Example 2-1, except that a reinforced inter-paper paper of 1000 kJ / cm² was used and a block polypropylene resin (block PP) was used for the thermoplastic resin layer. In Comparative Example 2-3, the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer.

[0156] (Comparative Example 2-4) A base paper layer having a thickness of 31 μm (basis weight 30 g / m ２ A decorative sheet of Comparative Example 2-4 was obtained in the same manner as in Example 2-1, except that a reinforced inter-paper paper of 1000 kJ / cm2 was used and the thickness of the thermoplastic resin layer was 8 μm. In Comparative Example 2-4, the thickness of the thermoplastic resin layer was 26% of the thickness of the base paper layer.

[0157] (Comparative Example 2-5) A base paper layer having a thickness of 55 μm (basis weight 50 g / m ２ A decorative sheet of Comparative Example 2-5 was obtained in the same manner as in Example 2-1, except that a reinforced inter-paper paper of 1000 kJ / cm2 was used and the thickness of the thermoplastic resin layer was 10 μm. In Comparative Example 2-5, the thickness of the thermoplastic resin layer was 18% of the thickness of the base paper layer.

[0158] (Comparative Example 2-6) A base paper layer having a thickness of 31 μm (basis weight 30 g / m ２ A decorative sheet of Comparative Example 2-6 was obtained in the same manner as in Example 2-1, except that a 16 μm thick thermoplastic resin layer was formed by melt extrusion molding using low-density polyethylene (LDPE) and inter-paper reinforced paper (Comparative Example 2-6). In Comparative Example 2-6, the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer.

[0159] (Comparative Example 2-7) A base paper layer having a thickness of 31 μm (basis weight 30 g / m ２ The decorative sheet of Comparative Example 2-7 was obtained in the same manner as in Example 2-1, except that a 16 μm thick thermoplastic resin layer was formed by melt extrusion molding using medium density polyethylene (MDPE) and inter-paper reinforced paper (Comparative Example 2-7). In Comparative Example 2-7, the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer.

[0160] (Comparative Example 2-8) A base paper layer having a thickness of 31 μm (basis weight 30 g / m ２ A decorative sheet of Comparative Example 2-8 was obtained in the same manner as in Example 2-1, except that a 16 μm thick thermoplastic resin layer was formed by melt extrusion molding using high density polyethylene (HDPE) and inter-paper reinforced paper (Comparative Example 2-8). In Comparative Example 2-8, the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer.

[0161] (Test 2-1) A pencil hardness test was carried out on the decorative sheets of Examples 2-1 and 2-2 and Comparative Examples 2-1 to 2-8. The pencil hardness test was carried out in accordance with JIS K 5600.

[0162] Specifically, a decorative sheet was attached to a substrate such as MDF using a vinyl acetate adhesive to create a decorative board, and a pencil attached to a test device was moved at a speed of 1 mm / s so that the lead was placed on the upper surface of the decorative board. A pencil with a flattened tip was used. In the pencil used in the pencil hardness test, the tip of the lead was the part that came into contact with the surface of the decorative board.

[0163] In the pencil hardness test, the test was carried out using pencils with lead hardnesses of 2B, B, HB, F, H, 2H, and 3H, and the state of the indentations on the surface of the decorative board was confirmed to evaluate the surface hardness. Specifically, the hardness of the pencil leads used in the test was increased in order from 2B to 3H, and the hardness of the lead at which peeling occurred between the base paper layer and the thermoplastic resin layer and the hardness of the lead at which a dent occurred on the surface of the decorative board were confirmed to evaluate the hardness.

[0164] The evaluation criteria were divided into two stages, with ◯ being considered a pass. ◯ (Good): The hardness of the lead where peeling occurred was HB or higher, and the hardness of the lead where denting occurred was H or higher. × (Poor): The hardness of the lead where peeling occurred was less than HB, and / or the hardness of the lead where denting occurred was less than H.

[0165] (Test 2-2) A curling evaluation test was conducted on the decorative sheets of Examples 2-1 and 2-2 and Comparative Examples 2-1 to 2-8. In the curling evaluation test, the decorative sheets were cut into 10 cm squares and left to stand for two days, and the height from the flat center to the tips of the four corners was measured, and the average of the measured heights was calculated and evaluated. The height from the flat center to the tips of the four corners refers to the distance in the vertical direction.

[0166] The evaluation criteria were based on three levels, with × being a failure. ⊚ (Excellent): The calculated average value was less than 3 cm. ◯ (Good): The calculated average value was 3 cm or more and less than 5 cm. × (Poor): The calculated average value was 5 cm or more.

[0167] (Test Results) The results of Tests 2-1 and 2-2 are shown in Table 2. Table 2 shows the ratio of the thickness of the thermoplastic resin layer to the thickness of the base paper layer, and the thickness and material of the thermoplastic resin layer for the decorative sheets of Examples 2-1 and 2-2 and Comparative Examples 2-1 to 2-8. Table 2 also shows the hardness of the cores that peeled off and the hardness of the cores that dented in Test 2-1, as well as the evaluation results for Test 2-1.

[0168] The decorative sheet 10 of Example 2-1, in which homopolypropylene resin was used as the material for the thermoplastic resin layer 2a and the thickness of the thermoplastic resin layer 2a was 62% of the thickness of the base paper layer 1 and 10 μm or more, showed good results in Tests 2-1 and 2-2.

[0169] The decorative sheet 10 of Example 2-2, in which homopolypropylene resin was used as the material for the thermoplastic resin layer 2a and the thickness of the thermoplastic resin layer 2a was 52% of the thickness of the base paper layer 1 and 10 μm or more, showed good results in Tests 2-1 and 2-2.

[0170] The decorative sheet of Comparative Example 2-1, in which homopolypropylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 86% of the thickness of the base paper layer and 10 μm or more, failed Test 2-2.

[0171] The decorative sheet of Comparative Example 2-2, in which a random polypropylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer and 10 μm or more, failed Test 2-1.

[0172] The decorative sheet of Comparative Example 2-3, in which a block polypropylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer and 10 μm or more, failed Test 2-1.

[0173] The decorative sheet of Comparative Example 2-4, in which homopolypropylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 26% of the thickness of the base paper layer and less than 10 μm, failed Test 2-1.

[0174] The decorative sheet of Comparative Example 2-5, in which homopolypropylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 18% of the thickness of the base paper layer and 10 μm or more, failed Test 2-1.

[0175] The decorative sheet of Comparative Example 2-6, in which low-density polyethylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer and 10 μm or more, failed tests 2-1 and 2-2.

[0176] The decorative sheet of Comparative Example 2-7, in which a medium-density polyethylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer and 10 μm or more, failed tests 2-1 and 2-2.

[0177] The decorative sheet of Comparative Example 2-8, in which high-density polyethylene resin was used as the material for the thermoplastic resin layer and the thickness of the thermoplastic resin layer was 52% of the thickness of the base paper layer and 10 μm or more, failed tests 2-1 and 2-2.

[0178] As shown in Table 2, decorative sheet 10 having a thermoplastic resin layer 2a containing homopolypropylene resin and having a thickness of 20% to 80% of the thickness of base paper layer 1 and 10 μm or more has excellent surface strength and can suppress curling.

[0179]

[0180] REFERENCE SIGNS 100 Decorative board 10 Decorative sheet 1 Base paper layer 2, 2a Thermoplastic resin layer 3 Base colored layer 4 Picture pattern layer 5 First surface protective layer 6 Second surface protective layer 20 Base material V Vertical direction UP Upper side LO Lower side

Claims

1. A decorative sheet comprising: a base paper layer; a thermoplastic resin layer provided on the upper side of the base paper layer; and a picture pattern layer provided on the upper side of the thermoplastic resin layer, wherein the peel strength of the base paper layer is 150 gf or more.

2. The decorative sheet according to claim 1, wherein the peel strength between the base paper layer and the thermoplastic resin layer is 9.0 N or more.

3. The base paper layer has a basis weight of 20 g / m ２ More than 100g / m ２ The decorative sheet according to claim 1 or 2, wherein:

4. A decorative sheet according to any one of claims 1 to 3, wherein the thickness of said thermoplastic resin layer is 10 μm or more and is 20% to 80% of the thickness of said base paper layer.

5. A decorative sheet according to any one of claims 1 to 3, wherein the thermoplastic resin layer has a thickness of 20% to 80% of the thickness of the base paper layer and 10 μm or more, and contains a homopolypropylene resin.

6. A decorative sheet according to any one of claims 1 to 5, comprising a base colored layer provided on the upper side of said thermoplastic resin layer and on the lower side of said picture pattern layer.

7. The decorative sheet according to claim 6, wherein said base color layer contains an isocyanate curing agent, and said thermoplastic resin layer has been subjected to corona treatment on the upper surface on which said base color layer is provided.

8. A decorative sheet according to any one of claims 1 to 7, comprising: a first surface protective layer provided above the picture and pattern layer; and a second surface protective layer provided above the first surface protective layer and in a position that is in harmony with the pattern of the picture and pattern layer, the second surface protective layer having a gloss different from that of the first surface protective layer, wherein the first surface protective layer and the second surface protective layer contain a urethane-based resin.

9. A decorative board comprising: a decorative sheet according to any one of claims 1 to 8; and a substrate provided below the decorative sheet.

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