Decorative sheets and decorative panels

Abstract

To provide decorative sheets and decorative panels using the same that reproduce the warmth of wood through touch, have excellent low-gloss design, and further improve scratch resistance and stain resistance. [Solution] A decorative sheet comprising a pattern layer and a surface protection layer in at least this order on one side of a sheet base layer, wherein the decorative sheet has a wood grain pattern, the pattern layer comprises a pattern ink layer and a vascular ink layer that partially covers the pattern ink layer and represents the vascular tissue of the wood grain, and the surface protection layer has a first protection layer on which at least a portion of the surface is exposed, the surface of the first protection layer has an uneven structure, the uneven structure has a load length ratio Rmr(10%) at a cutting level of 10% of 0.05 to 0.35, and a root mean square slope Rdq of 0.15 to 0.4.

Description

[Technical Field]

[0001] This invention relates to decorative sheets and decorative panels. [Background technology]

[0002] Decorative sheets are sheets with colors or patterns printed on their surface, and are widely used for interior decoration of fixtures and furniture, as well as exterior decoration of exterior walls and entrance doors. By applying decorative sheets printed with the grain patterns of trees or stones such as marble to an object, it is possible to reproduce the texture and feel of natural materials, and these are used as substitutes for genuine natural materials.

[0003] Decorative sheets require a high level of design to replicate natural materials. Furthermore, since they are applied to the interior and exterior of buildings, high durability is also required. For example, Patent Document 1 discloses a decorative material that provides aesthetic appeal, excellent scratch resistance, and superior stain resistance. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-119138 [Overview of the project] [Problems that the invention aims to solve]

[0005] When a low-gloss appearance is required for aesthetic purposes, it is common to add a matting additive to the surface protective layer. However, when the inorganic particles contained in the matting additive are exposed on the surface, it becomes prone to scratches, and furthermore, contamination tends to progress from the scratched areas. Furthermore, since humans perceive the warmth of wood from elements such as the visual impression of the wood grain and its texture, there is a demand for decorative sheets that reproduce these elements.

[0006] This invention has been made in view of the above circumstances, and aims to provide a decorative sheet and a decorative panel using the same that reproduce the warmth of wood by touch, have excellent low-gloss design, and further have improved durability. [Means for solving the problem]

[0007] The present invention encompasses the following embodiments. [1] A decorative sheet comprising, at least in this order, a pattern layer and a surface protection layer on one of the sheet base layers, wherein the decorative sheet has a wood grain pattern, the pattern layer comprises a pattern ink layer and a vascular ink layer that partially covers the pattern ink layer and represents the vascular tissue of the wood grain, the surface protection layer has a first protective layer on which at least a portion of the surface is exposed, the surface of the first protective layer has an uneven structure, the uneven structure has a load length ratio Rmr(10%) at a cutting level of 10% of 0.05 or more and 0.35 or less, and a root mean square slope Rdq of 0.15 or more and 0.4 or less, the decorative sheet. [2] The decorative sheet according to [1], wherein the thickness of the first protective layer is 2 μm or more and 10 μm or less. [3] The decorative sheet according to [1] or [2], wherein the surface protective layer comprises the first protective layer and the second protective layer which covers a part of the surface of the first protective layer and is laminated on the first protective layer, and the second protective layer is a layer with a higher gloss than the first protective layer. [4] The decorative sheet according to [3], wherein, in a plan view, the region in which the first protective layer is exposed and the conduit ink layer are in harmony. [5] The decorative sheet according to [3], wherein, in a plan view, the region on which the second protective layer is formed and the conduit ink layer are in harmony. [6] The decorative sheet according to [3], wherein the thickness of the first protective layer is 2 μm or more and 10 μm or less, and the sum of the thickness of the first protective layer and the thickness of the second protective layer is 3 μm or more and 30 μm or less. [7] A decorative sheet comprising, at least in this order, a pattern layer and a surface protection layer on one of the sheet base layers, wherein the decorative sheet has a wood grain pattern, the pattern layer comprises a pattern ink layer and a vascular ink layer that partially covers the pattern ink layer and represents the vascular tissue of the wood grain, the surface protection layer comprises a first protective layer having an uneven surface structure and a second protective layer provided between the pattern layer and the first protective layer and covering the surface of the pattern layer, the first protective layer is laminated on the second protective layer by covering a part of the surface of the second protective layer, the second protective layer is a layer with a higher gloss than the first protective layer, and the uneven structure has a load length ratio Rmr(10%) at a cutting level of 10% of 0.05 or more and a root mean square slope Rdq of 0.15 or more and 0.4 or less. [8] The decorative sheet according to [7], wherein, in a plan view, the region in which the second protective layer is exposed and the conduit ink layer are in harmony. [9] The decorative sheet according to [7], wherein, in a plan view, the region on which the first protective layer is formed and the conduit ink layer are in harmony.

[10] The decorative sheet according to any one of [7] to [9], wherein the thickness of the first protective layer is 2 μm or more and 10 μm or less, and the thickness of the second protective layer and the sum of the thicknesses of the second protective layer are 3 μm or more and 30 μm or less.

[11] The decorative sheet according to any one of [1] to

[10] , wherein the gloss of the first protective layer is less than 10.

[12] The decorative sheet according to any one of [1] to

[11] , wherein the first protective layer comprises a cured resin and particles.

[13] The decorative sheet according to

[12] , wherein the average particle size of the particles is 3 μm or more.

[14] The decorative sheet according to

[12] , wherein the average particle size of the particles is 3 μm or more and 10 μm or less.

[15] The decorative sheet according to any one of

[12] to

[14] , wherein the content of the particles in 100 parts by mass of the resin is 3 parts by mass or more and 11 parts by mass or less.

[16] The resin is an ionizing radiation-curable resin, the decorative sheet according to any one of

[12] to

[15] .

[17] The radiation-curable resin is acrylate, and the decorative sheet according to

[16] .

[18] The acrylate is a trifunctional acrylate containing a repeating structure, and the number of repetitions of the repeating structure is 15 or more and 20 or less, and the decorative sheet according to

[17] .

[19] The acrylate is a tetrafunctional acrylate containing a repeating structure, and the number of repetitions of the repeating structure is 20 or more and 35 or less, and the decorative sheet according to

[17] .

[20] The second protective layer includes a two-component curable urethane resin containing a polyester polyol and an isocyanate compound, and the decorative sheet according to [3].

[21] The sheet base material layer is composed of a single-layer paper base material, and the decorative sheet according to any one of [1] to

[20] .

[22] The sheet base material layer includes a first paper base material, a moisture-proof resin layer, and a second paper base material in this order, and the decorative sheet according to any one of [1] to

[21] .

[23] A decorative board obtained by laminating the decorative sheet according to any one of [1] to

[22] and a substrate via an adhesive layer.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a decorative sheet that reproduces the warmth of wood by touch, has excellent low-gloss design properties, and further has improved durability, and a decorative board using the same.

Brief Description of the Drawings

[0009] [Figure 1] It is a cross-sectional view schematically showing a decorative board of the first embodiment. [Figure 2] It is a cross-sectional view schematically showing a decorative board of the second embodiment. [Figure 3] It is a cross-sectional view schematically showing a decorative board of the third embodiment. [Figure 4] It is a cross-sectional view schematically showing a decorative board of the fourth embodiment. [Figure 5] It is a cross-sectional view schematically showing a decorative board of the fifth embodiment. [Figure 6]This is a microscopic image of the surface of the first protective layer. [Modes for carrying out the invention]

[0010] In this specification, durability means resistance to fingerprints, chemicals, scratches, and stains, and is evaluated by the methods described in the examples. Fingerprint resistance means that fingerprints are less noticeable. Chemical resistance means that when exposed to chemicals, the material is less likely to change in condition, such as losing its gloss or turning white. Scratch resistance refers to the ability to resist scratches and maintain a consistent gloss level. Stain resistance refers to the ease with which dirt can be wiped off, as defined in the stain A test specified by the Japanese Agricultural Standards (JAS).

[0011] <Decorative sheets and decorative panels> The decorative sheets and decorative panels of the present invention can reproduce the warmth of wood through touch. Because the air contained within the cells of natural wood acts as an insulator, wood has low thermal conductivity. For example, when a person touches wood with their hand, the heat from their hand does not easily transfer to the wood, and the heat remains in the hand, making it feel warm, thus creating a feeling of "warmth."

[0012] The decorative sheet of the present invention has a first protective layer that can be touched by human hands and has a predetermined uneven structure. This uneven structure replicates the cellular structure of natural wood and exhibits heat conductivity similar to that of wood, thus recreating the "warmth of wood." Furthermore, since the decorative sheet of the present invention has a predetermined uneven structure in its first protective layer, it can achieve a low gloss level without using a matting additive.

[0013] The decorative sheet according to this embodiment will be described below with reference to the drawings. Note that in all the following drawings, the dimensions and proportions of each component have been varied as appropriate for clarity. The items described below can be incorporated into each of the above embodiments, either individually or in combination.

[0014] Furthermore, the embodiments shown below illustrate configurations for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited by the material, shape, and structure of the components described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the claims described in the claims.

[0015] ≪First Embodiment≫ A first embodiment of the present invention will be described with reference to Figure 1. In Figure 1, the decorative panel 101 is formed by bonding a decorative sheet 1 to a substrate 9 via an adhesive layer 8. The decorative sheet 1 comprises, at least in this order, a pattern layer 11 and a first protective layer 12 on one side of the sheet base layer 10.

[0016] The pattern layer 11 comprises a pattern ink layer 11a and a vascular ink layer 11b that partially covers the pattern ink layer 11a and represents the vascular tissue of the wood grain. The decorative sheet 1 has a wood grain pattern by having a patterned layer 11.

[0017] In the decorative sheet 1, the first protective layer 12 covers the surface of both the pattern ink layer 11a and the conduit ink layer 11b. In the decorative sheet 1, the first protective layer 12 is the outermost layer that a person can touch with their hand, and the first protective layer 12 has an uneven surface structure on its surface 12S. In the decorative sheet 1, the entire surface 12S of the first protective layer 12 is exposed. Here, "exposed" means that the layer is located at the uppermost layer in a plan view, and the surface of the layer is exposed.

[0018] In the first embodiment, the uneven structure of the surface 12S of the first protective layer 12 has a load length ratio Rmr(10%) at a cutting level of 10% that is 0.05 or more and 0.35 or less, preferably 0.06 or more and 0.34 or less.

[0019] The load length ratio Rmr(10%) is the ratio of the load length of the roughness curve at cutting level 10% to the evaluation length. Cutting level 10% is the level where the distance in the depth direction from the highest point of the roughness curve is 10% of the maximum cross-sectional height Rt. When a user lightly touches a textured surface with their finger, their finger touches the portion from the highest point of the protrusion to approximately 10% of the height of the protrusion. Therefore, the load length ratio Rmr(10%) correlates with the amount of contact between the finger and the protrusion when a user lightly touches the textured surface with their finger. The load length ratio Rmr(10%) and the maximum cross-sectional height Rt are surface texture parameters specified in JIS B0601:2013.

[0020] The load length ratio Rmr(10%) is expressed by the following equation 1.

[0021]

number

[0022] In Equation 1, where ln is the evaluation length and Ml(10%) is the load length of the roughness curve at cutting level 10%.

[0023] In the first embodiment, the uneven structure of the surface 12S of the first protective layer 12 has a root mean square slope Rdq of 0.15 or more and 0.4 or less. Preferably, the root mean square slope Rdq is 0.2 or more and 0.35 or less, and more preferably 0.25 or more and 0.3 or less.

[0024] The root mean square slope Rdq is the root mean square of the local slope of the roughness curve at a reference length. The root mean square slope Rdq is a parameter that can be used to evaluate the magnitude of the local slope angle. Specifically, the root mean square slope Rdq quantifies the steepness of the convex or concave parts of a surface texture. The root mean square slope Rdq is a surface texture parameter specified in JIS B0601:2013.

[0025] The root mean square slope Rdq is expressed by the following equation 2.

[0026]

number

[0027] In Equation 2, l is the reference length and dZ(x) / dx is the local slope of the roughness curve.

[0028] The decorative sheet 1 comprises a first protective layer 12 in which the Rmr (10%) and Rdq of the surface uneven structure satisfy the above range. A person who touches the surface of such a decorative sheet 1 can feel the "warmth of wood". The uneven structure, where Rmr (10%) and Rdq satisfy the above range, replicates the cellular structure of natural wood, and the air contained within the uneven structure acts as an insulator. Therefore, when a person touches the decorative sheet 1 with their hands or fingers, the heat from that person is not easily conducted to the decorative sheet 1. As a result, the decorative sheet 1 can replicate the warmth of wood through touch.

[0029] Furthermore, the protrusions that form an uneven structure where Rmr (10%) and Rdq satisfy the above range have a moderately gentle slope and a moderate size in the height direction. Therefore, when a person slides their hands or fingers over the surface of the decorative sheet 1, the decorative sheet 1 stimulates the person's hands and fingers, giving the person a moderately rough texture, that is, a wood-like texture.

[0030] Furthermore, when the frequency of irregularities in an uneven structure is similar, an uneven structure with steeply shaped peaks has a higher load length ratio Rmr(10%) than an uneven structure with gently shaped peaks. In this case, it is possible to distinguish between the two using only the load length ratio Rmr(10%) parameter. On the other hand, an uneven structure with steeply shaped peaks and a high frequency of irregularities may have a similar load length ratio Rmr(10%) to an uneven structure with gently shaped peaks and a low frequency of irregularities. In this case, it is not possible to distinguish between the two using only the load length ratio Rmr(10%) parameter. In other words, the load length ratio Rmr(10%) parameter alone cannot express that the protrusions of an uneven structure have a moderately gentle slope and are of a moderate size in the height direction (i.e., give the user a wood-like tactile sensation). Therefore, it is appropriate to use the load length ratio Rmr (10%) in combination with the root mean square slope Rdq as a parameter to express the "warmth of wood." Furthermore, it is preferable to combine this with the root mean square height Rq, which will be described later, as a parameter to express the "warmth of wood."

[0031] Since the first protective layer 12 of the decorative sheet 1 has the above-described uneven structure, it can achieve a low gloss level even without containing a gloss adjuster (matte additive). Because gloss adjusters reduce the oil repellency of the layer formed by the resin material, fingerprints are easily left on protective layers containing gloss adjusters. On the other hand, the first protective layer 12, which does not contain gloss adjusters, is less likely to absorb oil, and therefore less likely to leave fingerprints. In addition, the first protective layer 12, which has excellent oil repellency, is less prone to oil stains and less likely to attract contaminants.

[0032] Furthermore, one of the causes of changes in gloss or scratches is the shedding of gloss-adjusting particles from the surface of the protective layer containing the gloss-adjusting agent. Since the first protective layer 12 does not contain a gloss-adjusting agent, it is less prone to changes in gloss or scratches.

[0033] Furthermore, the glossiness of the first protective layer 12 is preferably less than 10, and more preferably 5 or less. Here, "glossiness" is the measured value obtained by measuring at an incident angle of 60 degrees using a gloss meter compliant with JIS Z8741:1997.

[0034] If the glossiness of the first protective layer 12 is low enough to meet the above range, external light will not reflect easily onto the surface of the first protective layer 12. Therefore, for example, the wood grain pattern of the patterned layer 11, which has a wood grain pattern, can be clearly seen. In this case, it is particularly easy to give the user a "warmth of wood." Note that a textured structure in which Rmr (10%) and Rdq meet the above range is associated with low gloss, but other parameters besides this textured structure are also involved in achieving low gloss. For this reason, a low-gloss decorative sheet does not necessarily meet the requirements of the above-mentioned textured structure.

[0035] In the first embodiment, the uneven structure of the surface 12S of the first protective layer 12 is preferably such that the root mean square height Rq is 0.4 μm or more and 4.0 μm or less.

[0036] The root mean square height Rq is the root mean square of the vertical coordinate value Z(x) of the roughness curve at a reference length l. The root mean square height Rq is a parameter that can be used to evaluate the height of the protrusions or depressions contained in a surface texture. The root mean square height Rq is a surface texture parameter specified in JIS B0601:2013.

[0037] The root mean square height Rq is expressed by the following equation 3.

[0038]

number

[0039] In Equation 3, l is the reference length and Z(x) is the y-coordinate value of the roughness curve.

[0040] ≪Second Embodiment≫ A second embodiment of the present invention will be described with reference to Figure 2. In the decorative panel 102 shown in Figure 2, the decorative sheet 2 is bonded to the substrate 9 via an adhesive layer 8. The decorative sheet 2 comprises, on one side of the sheet base layer 10, a pattern layer 11, a first protective layer 12, and a second protective layer 13 that partially covers the surface of the first protective layer 12, in at least this order. The differences from the first embodiment will be explained below.

[0041] In the decorative sheet 2, the first protective layer 12 covers the surface of both the pattern ink layer 11a and the conduit ink layer 11b. In the decorative sheet 2, the surface 12S of the first protective layer 12 and the surface 13S of the second protective layer 13 are the outermost layers that can be touched by hand, and the surface 12S of the first protective layer 12 has an uneven structure. In the decorative sheet 2, a portion of the surface 12S of the first protective layer 12 is exposed.

[0042] The second protective layer 13 is a layer with a higher gloss than the first protective layer 12 and is formed by covering a portion of the surface of the first protective layer 12. In one embodiment of the present invention, the gloss of the second protective layer 13 is, for example, 15 to 60 or 25 to 50, and is preferably 5 or more higher than the gloss of the first protective layer 12, and more preferably 10 or more higher.

[0043] As shown in Figure 2, the second protective layer 13 of the decorative sheet 2 covers the upper surface of the first protective layer 12 so as not to overlap with the tubing ink layer 11b when the decorative sheet 2 is viewed from above (viewed in the thickness direction). That is, in the first protective layer 12, the area in which the first protective layer 12 is exposed from between the second protective layer 13 and the tubing ink layer 11b are precisely in line. In this specification, this positional relationship is referred to as "synchronized". In other words, in the decorative sheet 2, the area in which the first protective layer is exposed and the tubing ink layer 11b are synchronized when viewed from above. This synchronization of the area in which the first protective layer is exposed and the tubing ink layer 11b when viewed from above allows for a three-dimensional effect to be added to the design.

[0044] ≪Third Embodiment≫ A third embodiment of the present invention will be described with reference to Figure 3. In the decorative panel 103 shown in Figure 3, the decorative sheet 3 is bonded to the substrate 9 via an adhesive layer 8. The decorative sheet 3 comprises, on one side of the sheet base layer 10, a pattern layer 11, a first protective layer 12, and a second protective layer 13 that partially covers the surface of the first protective layer 12, in at least this order. The differences from the second embodiment will be explained below.

[0045] The second protective layer 13 is formed by covering a portion of the surface of the first protective layer 12. As shown in Figure 3, when the decorative sheet 3 is viewed from above (viewed in the thickness direction), the second protective layer 13 of the decorative sheet 3 covers the upper surface of the first protective layer 12 so as to overlap with the tubing ink layer 11b. In other words, in a plan view, the area where the second protective layer 13 is formed on the decorative sheet 3 is in harmony with the tubing ink layer 11b.

[0046] In the second and third embodiments, the second protective layer 13 covers a portion of the surface 12S of the first protective layer 12, leaving a portion of the surface 12S of the first protective layer 12 exposed. The extent to which the first protective layer 12 is exposed depends on the pattern applied to the pattern ink layer and the formation position of the vascular ink layer. Even if a portion of the surface is covered by the second protective layer 13, if the surface 12S of the first protective layer 12 is exposed, the impression of the surface of the first protective layer 12 becomes dominant in the outermost layer that a person can touch, and the uneven structure of the surface of the first protective layer 12 allows one to feel the warmth of wood.

[0047] ≪Fourth Embodiment≫ A fourth embodiment of the present invention will be described with reference to Figure 4. In the decorative panel 104 shown in Figure 4, the decorative sheet 4 is bonded to the substrate 9 via an adhesive layer 8. The decorative sheet 4 comprises, on one side of the sheet base layer 10, a pattern layer 11, a second protective layer 13, and a first protective layer 12 that partially covers the second protective layer 13, in at least this order. The differences from the first embodiment will be explained below.

[0048] In the decorative sheet 4, the second protective layer 13 covers the surface of both the pattern ink layer 11a and the conduit ink layer 11b. In the decorative sheet 4, the surface 12S of the first protective layer 12 and the surface 13S of the second protective layer 13 are the outermost layers that can be touched by a person's hand, and the first protective layer 12 has an uneven surface structure on its surface 12S.

[0049] The first protective layer 12 is formed by covering a portion of the surface of the second protective layer 13. As shown in Figure 4, the first protective layer 12 of the decorative sheet 4 covers the upper surface of the second protective layer 13 so as not to overlap with the tubing ink layer 11b when the decorative sheet 4 is viewed from above (viewed in the thickness direction). In the decorative sheet 4, the area where the second protective layer 13 is exposed from between the first protective layer 12 overlaps precisely with the tubing ink layer 11b. In other words, in a plan view, the area where the second protective layer 13 is exposed and the tubing ink layer 11b are in sync.

[0050] ≪Fifth Embodiment≫ A fifth embodiment of the present invention will be described with reference to Figure 5. In the decorative panel 105 shown in Figure 5, the decorative sheet 5 is bonded to the substrate 9 via an adhesive layer 8. The decorative sheet 5 comprises, on one side of the sheet base layer 10, a pattern layer 11, a second protective layer 13, and a first protective layer 12 that partially covers the second protective layer 13, in at least this order. The differences from the fourth embodiment will be explained below.

[0051] The first protective layer 12 is formed by covering a portion of the surface of the second protective layer 13. As shown in Figure 5, the second protective layer 13 of the decorative sheet 5 covers the upper surface of the first protective layer 12 so as to overlap with the tubing ink layer 11b when the decorative sheet 5 is viewed in plan (viewed in the thickness direction). In other words, the region on the decorative sheet 5 where the first protective layer 12 is formed and the tubing ink layer 11b are in sync.

[0052] [Explanation of each layer] The following describes the layers that make up the decorative sheet and the decorative panel.

[0053] (Sheet base layer 10) The material used to form the sheet substrate layer 10 is a known printable material. A fibrous sheet such as tissue paper or titanium paper can be used as the material for forming the sheet substrate layer 10. Alternatively, a resin sheet such as polyethylene, polypropylene, or polyvinyl chloride may be used as the material for forming the sheet substrate layer 10. The sheet substrate layer 10 may be a single layer or a laminate. The sheet substrate layer 10 is preferably composed of a single layer of paper substrate.

[0054] Furthermore, it is preferable that the sheet substrate layer 10 comprises a first paper substrate, a moisture-proof resin layer, and a second paper substrate in this order. For the first and second paper substrates, fibrous sheets such as tissue paper or titanium paper can be used. The moisture-proof resin layer is a layer made of a moisture-proof resin that does not allow water vapor to pass through. Thermoplastic resins such as olefin resins can be used as the material for forming the moisture-proof resin layer. By sandwiching a moisture-proof resin layer that does not allow water vapor to pass through between a first paper substrate made of a fibrous sheet and a second paper substrate, moisture resistance can be imparted to the sheet substrate layer 10.

[0055] The thickness of the sheet substrate layer 10 is preferably in the range of 20 μm to 250 μm, taking into consideration factors such as printability and cost.

[0056] (Concealing layer) As an optional configuration, a concealing layer may be provided between the sheet base material layer 10 and the pattern layer 11. The concealing layer is a layer that provides concealment to the substrate to which the decorative sheet is attached. The concealing layer can be made of the same material as the pattern layer 11, which will be described later. The pigment contained in the concealing layer is preferably an opaque pigment, such as titanium dioxide or iron oxide, in order to provide concealment. In addition, to enhance concealment, it is possible to add metals such as gold, silver, copper, or aluminum to the material of the concealing layer. Generally, flake-shaped aluminum pieces are often added.

[0057] (Pattern layer 11) The pattern layer 11 is formed by printing onto the sheet substrate layer 10 using ink, and is a layer for adding a pattern that gives the decorative sheet an aesthetic appeal. The pattern layer 11 comprises a pattern ink layer 11a and a vascular ink layer 11b that partially covers the pattern ink layer 11a and represents the vascular tissue of the wood grain.

[0058] As the binder for the ink forming the pattern ink layer 11a, for example, nitrated cotton, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl bratil, polyurethane, acrylic, polyesters, or modified versions thereof can be used individually or in combination. The binder may be water-based, solvent-based, or emulsion type, and may be a one-component type or a two-component type using a curing agent. The pattern layer 11 may also be formed by curing a layer formed with a curable ink by irradiation with ultraviolet light or electron beams. Among these, the most common method is to use a urethane-based ink and cure it with isocyanate.

[0059] The ink used to form the pattern ink layer 11a may further contain, in addition to the binder, colorants such as pigments and dyes, extender pigments, solvents, and various additives, which are typically found in inks. Examples of commonly used pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolon, cobalt, phthalocyanine, carbon, titanium dioxide, iron oxide, mica, and other pearl pigments.

[0060] The vascular ink layer 11b is partially formed on the surface of the pattern ink layer 11a and is a layer that gives the decorative sheet a wood grain pattern by representing the vascular tissue of the wood grain. The ink used for the vascular ink layer 11b can be made from the same material as described above for the pattern ink layer 11a.

[0061] (Surface protective layer) The surface protective layer is a layer formed on top of the pattern layer 11. The surface protection layer has a first protective layer 12 in which at least a portion of the surface is exposed. One embodiment of the surface protection layer consists of a first protective layer 12 in which at least a portion of the surface is exposed. One embodiment of the surface protective layer comprises a first protective layer 12 that covers the surface of the pattern layer 11, and a second protective layer 13 that covers a part of the surface of the first protective layer 12 and is laminated on the first protective layer 12. One embodiment of the surface protective layer comprises a second protective layer 13 that covers the surface of the pattern layer 11, and a first protective layer 12 that covers a part of the surface of the second protective layer 13 and is laminated on the second protective layer 13.

[0062] ·1st protective layer 12 The surface of the first protective layer 12 has a ridged, uneven structure. Herein, in this specification, "ridge-like" refers to a convex shape that is linear in a plan view. The uneven structure of the first protective layer 12 may have a curved or straight shape when viewed from above. From the viewpoint of making it difficult for fingerprints to adhere to decorative sheets 1 to 5, the uneven structure is preferably curved. The ridge-like protrusions of the uneven structure may or may not be branched in a plan view.

[0063] Figure 6 is a micrograph of the surface of the first protective layer 12. As shown in Figure 6, the ridge-like convex shapes of the uneven structure are each curved, and at least some are adjacent in the width direction. At positions where at least some of the convex shapes are adjacent in the width direction, the cross-section of the first protective layer 12 parallel to this width direction and the thickness direction of the first protective layer 12 has a wave shape, such as a sinusoidal shape, in the portion where the uneven structure is provided. The scale in Figure 6 is "100 μm".

[0064] The thickness of the first protective layer 12 is preferably 2 μm or more and 10 μm or less, and more preferably 3 μm or more and 8 μm or less. If the thickness of the first protective layer 12 is greater than or equal to the lower limit mentioned above, when a person touches the wood with their hand, the heat from their hand does not easily transfer to the wood, and the heat remains in the hand, making it feel warmer and thus easier to perceive "warmth." If the thickness of the first protective layer 12 is less than or equal to the above upper limit, a decorative sheet or decorative panel can be made that is resistant to fingerprints, dirt, and scratches. Here, the thickness of the first protective layer 12 was determined by observing the cross-section with a scanning electron microscope and averaging 25 points. Specifically, the thickness of the first protective layer 12 can be measured by the following method.

[0065] [Thickness of the surface protective layer] The decorative sheet is embedded in a resin such as a cold-curing epoxy resin or a UV-curing resin and allowed to cure completely. Then, the sheet is cut so that the cross-section is exposed, and the measurement surface is obtained by mechanical polishing. Subsequently, the thickness of the first protective layer is measured using a scanning electron microscope (for example, a SIGMA500 scanning electron microscope manufactured by Carl Zeiss Microscopy).

[0066] Length measurements will be taken at 25 arbitrary points, and the average length value obtained from these 25 points will be defined as the "thickness of the surface protective layer." The measurement conditions will be an acceleration voltage of 0.5 keV (low acceleration voltage), SE2 mode for imaging, and a magnification of 2000x. Sputtering will not be performed on the measurement sample.

[0067] The first protective layer 12 preferably contains cured resin and particles. The resin contained in the first protective layer 12 is preferably an ionizing radiation-curable resin. Here, "ionizing radiation" refers to charged particle beams such as electron beams. Ionizing radiation-curable resins harden when irradiated with ionizing radiation. Ionizing radiation-curable resins can also harden when irradiated with ultraviolet light. The ionizing radiation-curable resin used here hardens when irradiated with light with a wavelength of 200 nm or less, while having a high absorption coefficient for this light.

[0068] The amount of cured ionizing radiation-curable resin in the first protective layer 12 is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. As the ionizing radiation-curable resin, known materials such as various monomers and commercially available oligomers can be used.

[0069] Examples of ionizing radiation-curable resins include (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. The ionizing radiation-curable resin may be either a water-based resin or a non-water-based (organic solvent-based) resin.

[0070] The main component of the ionizing radiation-curable resin is preferably acrylate. Here, the main component of the ionizing radiation-curable resin means a component that accounts for 60% by mass or more of the ionizing radiation-curable resin. The acrylate content relative to the total amount of the ionizing radiation-curable resin is preferably 70 parts by mass or more, and more preferably 80 parts by mass or more.

[0071] From the viewpoint of obtaining a first protective layer 12 that is more scratch-resistant, the resin is preferably a trifunctional or more functional acrylate, and more preferably a tetrafunctional or more functional acrylate.

[0072] The acrylate preferably contains a repeating structure. This repeating structure is preferably one of the following: an ethylene oxide (EO) structure, a propylene oxide (PO) structure, or an ε-caprolactone (CL) structure. The repeating structure is preferably ethylene oxide or propylene oxide. In the acrylate, the above repeating structure can be interposed between the acryloyl group and the methylol group in an open ring state.

[0073] The number of repetitions of the repeating structure is preferably 9 or more. If an acrylate with a high number of repetitions is used, expansion in the in-plane direction of the cured film is more likely to occur in the second irradiation step described later, and therefore, wrinkles corresponding to the uneven structure of the first protective layer 12 are more likely to occur on the surface of the coating film. Furthermore, using acrylates with a high number of repetitions tends to result in lower gloss values ​​and improved aesthetic appeal. However, increasing the number of repetitions reduces the crosslinking density, which decreases the scratch resistance of the surface protective layer. Conversely, using acrylates with a low number of repetitions may make it difficult to achieve high processability.

[0074] In a preferred embodiment, the ionizing radiation-curable resin is a trifunctional acrylate containing a repeating structure. The trifunctional acrylate containing a repeating structure is, for example, EO-modified, PO-modified, or CL-modified trimethylolpropane triacrylate, glycerin triacrylate, isocyanurate triacrylate, or pentaerythritol triacrylate. In the trifunctional acrylate containing a repeating structure, the number of repetitions of the repeating structure is preferably 15 or more and 20 or less.

[0075] In another preferred embodiment, the ionizing radiation-curable resin is a tetrafunctional acrylate containing a repeating structure. The tetrafunctional acrylate containing a repeating structure is, for example, EO-modified, PO-modified, or CL-modified pentaerythritol tetraacrylate. In the tetrafunctional acrylate containing a repeating structure, the number of repetitions of the repeating structure is preferably 20 to 35.

[0076] The number of repetitions in the above repeating structure can be analyzed using MALDI-TOF-MS. Ionizing radiation-curable resins may have a molecular weight distribution. If a molecular weight distribution exists, the number of repetitions should be the number of repetitions corresponding to the molecular weight with the strongest peak in the MALDI-TOF-MS mass spectrum.

[0077] The particles contained in the first protective layer 12 can be any particles that uniformly create wrinkles when the ionizing radiation-curable resin hardens. For example, such particles can be made of organic materials such as polyethylene (PE) wax, polypropylene (PP) wax, or resin beads, or of inorganic materials such as silica, glass, alumina, titania, zirconia, calcium carbonate, or barium sulfate.

[0078] The average particle size (D50) is preferably 3 μm or larger, more preferably 3 μm to 10 μm, and even more preferably 3 μm to 6 μm. In this embodiment, silica particles are preferred as the particles contained in the first protective layer 12, and silica particles with an average particle diameter of 3 μm or more and 6 μm or less are more preferred. Silica particles of this particle diameter are less prone to detachment due to friction, etc., and therefore less likely to cause scratches.

[0079] The particle content in the first protective layer 12 is preferably 5% by mass or more and 10% by mass or less, relative to 100% by mass of the main synthetic resin. When the particle content is within the above range, the possibility of contact between the particles and the contaminating substance is reduced. From the viewpoint of imparting low gloss to the decorative sheet, further reducing the likelihood of changes in gloss, and improving stain resistance, it is preferable that the particles contained in the first protective layer 12 satisfy the above-mentioned particle size and content ratio.

[0080] Silica particles are generally used as a matting agent, and the silica particle content used as a matting agent is approximately 40% by mass relative to 100% by mass of the main synthetic resin, with an average particle size of 5 μm to 15 μm.

[0081] When the first protective layer 12 contains particles, wrinkles can be generated more uniformly on the coating surface in the second irradiation step described later. If the average particle size (D50) is large, the particles are more likely to fall off the first protective layer 12, and scratches are more likely to occur starting from the areas where the particles have fallen off. Also, if the particles are too small, it becomes difficult to form uniform wrinkles.

[0082] Here, "average particle size (D50)" refers to the median diameter (D50) measured by a laser diffraction / scattering particle size distribution analyzer. The average particle size of the particles contained in the first protective layer 12 can be obtained by observing its cross-section, measuring the particle sizes of multiple particles, and averaging the result. The value obtained in this way is substantially the same as the median diameter (D50) measured by a laser diffraction / scattering particle size distribution analyzer. Therefore, the range of average particle size described above can also be interpreted as the range of average particle size of the particles contained in the first protective layer 12.

[0083] In one embodiment of the present invention, the particle content per 100 parts by mass of resin is preferably 3 parts by mass or more and 11 parts by mass or less, and more preferably 4 parts by mass or more and 8 parts by mass or less. Note that "100 parts by mass of resin" refers to the parts by mass of the solid content of the resin.

[0084] When the particle content is within the above range, wrinkles can be generated more uniformly on the surface of the coating in the second irradiation step described later. As a result, the gloss level decreases, and the aesthetic appeal is improved.

[0085] ·Second protective layer 13 The second protective layer 13 is a layer with a higher gloss level than the first protective layer 12. As the material for forming the second protective layer 13, urethane resin, acrylic resin, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, and polyester resin can be used. As the material for forming the second protective layer 13, a two-component curable urethane resin containing a polyester polyol and an isocyanate compound is preferred.

[0086] In one embodiment of the present invention, the thickness of the first protective layer 12 is 2 μm or more and 10 μm or less, and the sum of the thickness of the first protective layer 12 and the thickness of the second protective layer 13 is preferably 3 μm or more and 30 μm or less, and more preferably 13 μm or more and 25 μm or less. When the thickness of the first protective layer 12, the thickness of the first protective layer 12, and the sum of the thicknesses of the second protective layer 13 are within the above ranges, when a person touches the wood with their hand, the heat from their hand does not easily transfer to the wood, the heat remains in the hand, and they feel warm, making it easier to feel "warmth." Here, the sum of the thickness of the first protective layer 12 and the thickness of the second protective layer 13 can be measured by the method described in [Thickness of Surface Protective Layer] above.

[0087] (Base material 9) The base material 9 is, for example, a board. The board material is, for example, a wood-based board, an inorganic board, a metal plate, or a composite board made of multiple materials. The base material 9 may have a shape other than a board. The decorative materials 101 to 105 having the base material 9 which is a board are decorative panels. The decorative panels may be flat, bent, or folded.

[0088] The decorative materials 101 to 105 may also employ a material other than a plate as the base material 9. For example, the base material 9 may be a resin molded body.

[0089] (Adhesive layer 8) A urethane resin-based adhesive can be used as the material for forming the adhesive layer 8.

[0090] <Method for manufacturing decorative sheets 1> The decorative sheet 1, as described with reference to Figure 1, is manufactured, for example, by the following method.

[0091] As an example of a sheet substrate layer, we will explain using the case where tissue paper is used. A wood grain pattern is printed on one side of the tissue paper to form a pattern ink layer 11a. Furthermore, a vascular ink layer 11b is formed by partially covering the pattern ink layer 11a to represent the vascular tissue of the wood grain. For forming the pattern ink layer 11a and the tubing ink layer 11b by printing, known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be employed. Known printing inks suitable for the adopted printing method can be used for the pattern ink layer 11a and the tubing ink layer 11b.

[0092] Next, a first protective layer 12 is formed so as to cover the surfaces of both the pattern ink layer 11a and the conduit ink layer 11b.

[0093] (Preparation of coating solution for the first protective layer) First, prepare the coating liquid for the first protective layer and stir it. The coating liquid for the first protective layer is prepared, for example, by mixing the above-mentioned resin and the above-mentioned particles and stirring them by a known method. When preparing the coating solution for the first protective layer, the load length ratio Rmr (10%) can be controlled to the above range by adjusting the amount of particles added. Furthermore, the load length ratio Rmr (10%) can be controlled to the above range by adjusting the amount of the coating solution applied to the first protective layer. Furthermore, if the load length ratio Rmr(10%) of the resulting uneven structure is greater than the target value as a result of the manufacturing method of the decorative sheet, the load length ratio Rmr(10%) can be brought closer to the target value by reducing the amount of particles added to the preparation conditions of the coating liquid for the first protective layer.

[0094] The first protective coating solution may further contain a solvent and additives for improving the functionality of the final product, such as antimicrobial agents and antifungal agents. The first protective coating solution may further contain other additives such as ultraviolet absorbers and light stabilizers. Examples of ultraviolet absorbers include benzotriazole-based, benzoate-based, benzophenone-based, and triazine-based agents. Examples of light stabilizers include hindered amine-based agents. Furthermore, according to the method described herein, a first protective coating solution with low gloss can be formed without gloss modifiers (matting additives).

[0095] In the third irradiation step described later, when the entire coating film consisting of the first protective layer coating liquid is cured by ultraviolet irradiation, it is preferable that the first protective layer coating liquid further contains a photoinitiator. The photoinitiator is not particularly limited, but examples include benzophenone-based, acetophenone-based, benzoin ether-based, and thioxanthone-based photoinitiators.

[0096] (Formation of coating film) Next, a coating film consisting of a first protective coating liquid is formed so as to cover the surfaces of both the pattern ink layer 11a and the conduit ink layer 11b. This coating film can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing, or by various coating methods such as roll coating, knife coating, microgravure coating, and die coating.

[0097] (1st irradiation step) After forming a coating film consisting of the first protective layer coating liquid, the first irradiation step is performed. In the first irradiation step, light with a wavelength of approximately 200 nm to 400 nm (hereinafter referred to as the first radiation) is irradiated onto the coating film. This partially hardens the coating film. By partially hardening the coating film through the first irradiation step, the wrinkled uneven structure (texture) produced by the second irradiation step described later can be uniformly generated. Alternatively, by appropriately setting the irradiation conditions of the first irradiation step, it is possible to adjust the uneven structure, particularly the depth of the uneven structure.

[0098] For the first irradiation step, the light source can be selected from, for example, a high-pressure mercury lamp, a metal halide lamp, and a single-wavelength LED lamp having light with a wavelength of 200 nm to 400 nm.

[0099] The integrated light intensity in the first irradiation process is 2 mJ / cm². 2 More than 100mJ / cm 2 The following is preferable: 10 mJ / cm² 2 More than 80mJ / cm 2 It is more preferable to set it to the following: 20 mJ / cm² 2More than 60mJ / cm 2 The following is even more preferable: If the cumulative light intensity is reduced, the effect of the first irradiation step described above will not be observed. If the cumulative light intensity is increased, the coating film will fully harden, and wrinkles will not be formed in the subsequent second irradiation step.

[0100] (Second irradiation process) Next, the second irradiation process is carried out. In the second irradiation process, light with a wavelength of 200 nm or less (hereinafter referred to as the second radiation) is irradiated onto the coating film. The ionizing radiation-curable resin contained in the first protective layer coating liquid has a large absorption coefficient for the second irradiation light. Therefore, the second irradiation light incident on the coating film can only reach a distance of several tens to several hundreds of nanometers from its outermost surface. Consequently, in the second irradiation process, the crosslinking reaction proceeds in the surface region of the coating film, forming an extremely thin cured film, while in other regions, the crosslinking reaction does not proceed and the film remains semi-cured.

[0101] The coating film after the second irradiation process has wrinkles on its surface corresponding to the uneven surface structure of the first protective layer 12 described above. The inventors believe the reason why wrinkles form on the coating film surface due to the second irradiation process is as follows.

[0102] As described above, the second radiation can only reach a distance of tens to hundreds of nanometers from the outermost surface of the coating film. In other words, the crosslinking reaction of the ionizing radiation-curable resin due to irradiation with the second radiation occurs only at the surface of the coating film, and in regions further away from the outermost surface than tens to hundreds of nanometers, some areas remain uncured, and highly fluid molecules exist there. These highly fluid molecules swell the cured film, increasing its volume. As a result, it is thought that the cured film buckles in response to the in-plane compressive stress caused by the increase in volume in the in-plane direction, resulting in wrinkles on the surface of the coating film.

[0103] Furthermore, the inventors believe that the reason why the first protective layer 12 having surface properties characterized by the above-mentioned parameters can be obtained by the above method is as follows.

[0104] As described above, when a coating film made of the first protective layer coating liquid is irradiated with the second radiation, a hardened film is formed on its surface, and the hardened film increases in volume in the in-plane direction, causing wrinkles to form on the surface of the coating film. Since the second radiation is usually irradiated from a vertical direction, the increase in volume of the hardened film in the in-plane direction is greater in areas with a nearly horizontal surface compared to areas with an inclined surface. That is, at the tops of convex parts and the bottoms of concave parts, the rate of increase in volume of the hardened film in the in-plane direction is greater than in other parts.

[0105] Furthermore, during the process of creating this wrinkle shape, mass migration occurs within the coating film from areas corresponding to the recesses of the wrinkles to areas corresponding to the protrusions of the wrinkles. As a result, the thickness of the coating film decreases in the recessed areas and increases in the protruding areas. If the coating film is irradiated with the first radiation prior to the second radiation, the mass migration within the coating film due to the in-plane volume increase of the hardened film becomes gentler. In other words, if the coating film is irradiated with the first radiation, deformation of the coating film surface due to irradiation with the second radiation becomes less likely compared to cases where the first radiation irradiation is omitted. However, in areas with greater thickness, deformation is more likely to occur compared to areas with less thickness because there is a larger amount of material that can contribute to deformation.

[0106] Thus, in the convex areas, the rate of increase in the in-plane volume of the hardened film is large, and deformation is more likely to occur. Therefore, if irradiation with the second radiation is continued, the ridge-like convex areas formed on the surface of the coating film expand so that the portion of the cross-section perpendicular to its length that corresponds to the surface of the coating film becomes, for example, a convex curve, and its width also increases.

[0107] As the convex portions expand to have the cross-sectional shape described above, and the distance between the convex portions shortens, the amount of light from the second radiation reaching the concave portions decreases. Therefore, in the concave portions, the rate of increase in the in-plane volume of the hardened film decreases.

[0108] As a result, an uneven structure is formed that has characteristics such as a gentle slope near the top of the protrusions. In other words, it is considered that a first protective layer 12 having surface properties characterized by the above-mentioned parameters is obtained.

[0109] Furthermore, the uniformity of particle distribution within the coating film affects the uniformity of distribution in convex and concave areas, and therefore affects the surface properties of the first protective layer 12. Accordingly, the above method eliminates the non-uniformity of particle dispersion by stirring the coating liquid for the surface protective layer more strongly or for a longer period compared to a normal stirring method.

[0110] The second type of radiation can be extracted from excimer VUV (Vacuum Ultra Violet) light. Excimer VUV light can be generated from lamps using noble gases or noble gas halide compounds. When high-energy electrons are supplied from an external source to a lamp containing a noble gas or noble gas halide compound, numerous discharge plasmas (dielectric barrier discharges) are generated. This plasma discharge excites the atoms of the discharge gas (noble gas), causing them to momentarily enter an excimer state. When returning from this excimer state to the ground state, it emits light in a wavelength range specific to that excimer state.

[0111] The gas used in an excimer lamp can be any conventionally used gas, as long as it emits light of 200 nm or less. As gases, noble gases such as Xe, Ar, and Kr, or mixed gases of noble gases and halogen gases such as ArBr and ArF can be used. The wavelength (center wavelength) of an excimer lamp varies depending on the gas used, and for example, it has wavelengths of approximately 172 nm (Xe), approximately 126 nm (Ar), approximately 146 nm (Kr), approximately 165 nm (ArBr), and approximately 193 nm (ArF).

[0112] Considering the magnitude of the photon energy and the difference between the wavelength and the bonding energy of the organic material, it is preferable to use a xenon lamp that emits excimer light with a central wavelength of 172 nm as the light source. Furthermore, considering the costs of equipment maintenance and material availability, it is also preferable to use a xenon lamp as the light source.

[0113] The second irradiation step is carried out in an atmosphere with a low oxygen concentration. Oxygen has a large absorption coefficient for light of 200 nm or less. Therefore, the second irradiation step is preferably carried out, for example, in a nitrogen gas atmosphere. The oxygen concentration in the gas phase in the second irradiation step, that is, the residual oxygen concentration in the reaction atmosphere, is preferably 2000 ppm or less, and more preferably 1000 ppm or less.

[0114] Also, oxygen in the atmosphere inhibits radical polymerization. Therefore, the residual oxygen concentration in the reaction atmosphere affects the formation of wrinkles on the coating film surface. Therefore, when the residual oxygen concentration in the reaction atmosphere is changed, the surface properties of the first protective layer 12 can also change.

[0115] The integrated light quantity of the second radiation is 0.5 mJ / cm 2 or more and 200 mJ / cm 2 or less, preferably 1 mJ / cm 2 or more and 100 mJ / cm 2 or less, more preferably 3 mJ / cm 2 or more and 50 mJ / cm 2 or less, still more preferably 5 mJ / cm 2 or more and 30 mJ / cm 2 or less, and most preferably. When the integrated light quantity is reduced, the expansion of the cured film in the in-plane direction becomes smaller. When the integrated light quantity is increased, the surface state of the coating film deteriorates.

[0116] (Third Irradiation Step) After the second irradiation step is completed, the third irradiation step is carried out. In the third irradiation step, the coating film is irradiated with the third radiation to cure the entire coating film. Thereby, the first protective layer 12 is obtained.

[0117] The third radiation is ionizing radiation such as an electron beam or ultraviolet light having a longer wavelength compared to the first radiation.

[0118] The integrated light quantity of the third radiation is 10 mJ / cm 2 or more and 500 mJ / cm 2The following is preferable: 50 mJ / cm 2 More than 400mJ / cm 2 It is more preferable to use the following: 100 mJ / cm² 2 More than 300mJ / cm 2 The following is even more preferable.

[0119] The decorative sheet 1 can be manufactured, for example, by the method described above. Furthermore, it is believed that the first protective layer 12 having the above-described surface properties can be obtained by the method described above for the following reasons in addition to the reasons explained above.

[0120] In the second irradiation step, oxygen in the gas phase not only absorbs short-wavelength ultraviolet light but also inhibits radical polymerization. The effect of oxygen in the gas phase on radical polymerization is greatest in the portion of the coating film made of ionizing radiation-curable resin adjacent to the gas phase, and decreases as the distance from the coating film surface increases. Therefore, by changing the oxygen concentration in the gas phase in the second irradiation step, the relationship between the distance from the coating film surface and the progress of the crosslinking reaction can be changed.

[0121] When this relationship changes, the thickness of the cured film formed on the surface of the coating by the second irradiation process and the degree of expansion of the cured film in the in-plane direction in accordance with the progress of the crosslinking reaction change. The cumulative amount of light in the first and second irradiation processes also affects the thickness of the cured film and the degree of expansion of the cured film in the in-plane direction. Furthermore, the thickness of the cured film and the degree of expansion of the cured film in the in-plane direction affect the surface properties of the first protective layer 12. In addition, the particle size and amount of particles added in the coating film, as well as the thickness of the coating film, also affect the formation of wrinkles.

[0122] When this relationship changes, the thickness of the cured film formed on the surface of the coating by the second irradiation process and the degree of expansion of the cured film in the in-plane direction in accordance with the progress of the crosslinking reaction change. The cumulative amount of light in the first and second irradiation processes also affects the thickness of the cured film and the degree of expansion of the cured film in the in-plane direction. Furthermore, the thickness of the cured film and the degree of expansion of the cured film in the in-plane direction affect the surface properties of the first protective layer 12. In addition, the particle size and amount of particles added in the coating film, as well as the thickness of the coating film, also affect the formation of wrinkles.

[0123] Therefore, by appropriately setting, for example, the stirring method of the coating liquid for the first protective layer, the composition of the ionizing radiation-curable resin, the particle size and amount added, the thickness of the coating film, the oxygen concentration in the gas phase during the second irradiation step, and the cumulative light intensity during the first and second irradiation steps, a first protective layer 12 having the desired surface properties can be obtained. This makes it possible to create a decorative sheet that reproduces the texture (gloss, warmth, and feel) of the real material while also being highly durable.

[0124] <Method for manufacturing decorative sheets 2> The decorative sheet 2, as described with reference to Figure 2, is manufactured, for example, by the following method. As an example of a sheet substrate layer, we will explain using the case where tissue paper is used. A wood grain pattern is printed on one side of the tissue paper to form a pattern ink layer 11a. Furthermore, a vascular ink layer 11b is formed by partially covering the pattern ink layer 11a to represent the vascular tissue of the wood grain. For forming the pattern ink layer 11a and the tubing ink layer 11b by printing, known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be employed. Known printing inks suitable for the adopted printing method can be used for the pattern ink layer 11a and the tubing ink layer 11b.

[0125] Next, a first protective layer 12 is formed so as to cover the surfaces of both the pattern ink layer 11a and the tubing ink layer 11b. Then, a coating film 13 made of a second protective layer coating liquid is formed continuously on top of the first protective layer 12. The coating film 13 is formed on the upper part of the pattern ink layer 11a where the tubing ink layer 11b has not been formed. That is, the coating film 13 is formed on the upper part 13S of the pattern ink layer 11a where the tubing ink layer 11b has not been formed, and the upper part 12S of the tubing ink layer 11b is exposed on the first protective layer 12.

[0126] The coating film 13 can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing, or by various coating methods such as roll coating, knife coating, microgravure coating, and die coating.

[0127] <Method for manufacturing decorative sheets 3> The decorative sheet 3, as described with reference to Figure 3, is manufactured, for example, by the following method. As an example of a sheet substrate layer, we will explain using the case where tissue paper is used. A wood grain pattern is printed on one side of the tissue paper to form a pattern ink layer 11a. Furthermore, a vascular ink layer 11b is formed by partially covering the pattern ink layer 11a to represent the vascular tissue of the wood grain. For forming the pattern ink layer 11a and the tubing ink layer 11b by printing, known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be employed. Known printing inks suitable for the adopted printing method can be used for the pattern ink layer 11a and the tubing ink layer 11b.

[0128] Next, a first protective layer 12 is formed so as to cover the surfaces of both the pattern ink layer 11a and the tubing ink layer 11b. Then, a coating film 13 made of a second protective layer coating liquid is continuously formed on top of the first protective layer 12. The coating film 13 is formed on the upper part of the pattern ink layer 11a where the tubing ink layer 11b is formed. That is, the coating film 13 is formed on the upper part 13S of the pattern ink layer 11a where the tubing ink layer 11b is formed, and the upper part 12S of the first protective layer 12 where the tubing ink layer 11b is not yet formed is exposed.

[0129] The coating film 13 can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing, or by various coating methods such as roll coating, knife coating, microgravure coating, and die coating.

[0130] <Method for manufacturing decorative sheets 4> The decorative sheet 4, as described with reference to Figure 4, is manufactured, for example, by the following method. As an example of a sheet substrate layer, we will explain using the case where tissue paper is used. A wood grain pattern is printed on one side of the tissue paper to form a pattern ink layer 11a. Furthermore, a vascular ink layer 11b is formed by partially covering the pattern ink layer 11a to represent the vascular tissue of the wood grain. For forming the pattern ink layer 11a and the tubing ink layer 11b by printing, known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be employed. Known printing inks suitable for the adopted printing method can be used for the pattern ink layer 11a and the tubing ink layer 11b.

[0131] Next, a coating film 13 made of a second protective coating liquid is formed so as to cover the surfaces of both the pattern ink layer 11a and the tubing ink layer 11b. Then, a first protective layer 12 is formed continuously on top of the coating film 13. The first protective layer 12 is formed on the upper part of the pattern ink layer 11a where the tubing ink layer 11b has not been formed. That is, the first protective layer 12 is formed on the upper part 12S of the pattern ink layer 11a where the tubing ink layer 11b has not been formed, and the upper part 13S of the tubing ink layer 11b is exposed on the coating film 13.

[0132] The first protective layer 12 can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing, or by various coating methods such as roll coating, knife coating, microgravure coating, and die coating.

[0133] <5 Methods for Manufacturing Decorative Sheets> The decorative sheet 5, as described with reference to Figure 5, is manufactured, for example, by the following method. As an example of a sheet substrate layer, we will explain using the case where tissue paper is used. A wood grain pattern is printed on one side of the tissue paper to form a pattern ink layer 11a. Furthermore, a vascular ink layer 11b is formed by partially covering the pattern ink layer 11a to represent the vascular tissue of the wood grain. For forming the pattern ink layer 11a and the tubing ink layer 11b by printing, known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be employed. Known printing inks suitable for the adopted printing method can be used for the pattern ink layer 11a and the tubing ink layer 11b.

[0134] Next, a coating film 13 made of a second protective coating liquid is formed so as to cover the surfaces of both the pattern ink layer 11a and the tubing ink layer 11b. Then, a first protective layer 12 is formed continuously on top of the coating film 13. The first protective layer 12 is formed on the upper part of the pattern ink layer 11a on which the tubing ink layer 11b is formed. That is, the first protective layer 12 is formed on the upper part 12S of the pattern ink layer 11a on which the tubing ink layer 11b is formed, and the upper part 13S of the coating film 13 where the tubing ink layer 11b is not yet formed is exposed.

[0135] The first protective layer 12 can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing, or by various coating methods such as roll coating, knife coating, microgravure coating, and die coating. [Examples]

[0136] Next, the present invention will be described in more detail with reference to examples.

[0137] <Example 1> The decorative sheet 1, as described with reference to Figure 1, was manufactured by the following method. Basis weight 30g / m 2 Using a nitrocellulose-based gravure printing ink, an opacity layer and a pattern layer (pattern ink layer and tubular ink layer) were printed on the surface of the thin paper using a gravure printing press. Subsequently, the first protective coating liquid 1 described below was applied to the entire surface, covering the pattern ink layer and the conduit ink layer, to form a coating film.

[0138] (Coating liquid 1 for 1st protective layer) ·Ionizing radiation curable resin Type: Trimethylolpropane EO-modified triacrylate (EO 15 molar added) Product Name: SR9035 (manufactured by Sartomer) Blend: 100 parts by mass ·particle Product Name: Silysia 250N (Manufactured by Fuji Silysia Chemical Co., Ltd.) Particle size: 5μm Formula: 5 parts by mass

[0139] The ionizing radiation-curable resin used was a trifunctional acrylate containing a repeating structure with 15 repetitions. The coating thickness was 2 μm.

[0140] In the first irradiation step, the coating film is exposed to air using a high-pressure mercury lamp to emit ultraviolet light (main wavelength: 365 nm) at an integrated intensity of 60 mJ / cm². 2 The coating was irradiated until it reached a semi-cured state.

[0141] Next, in the second irradiation step, the coating film is subjected to ultraviolet light (wavelength 172 nm) using a Xe excimer lamp in a nitrogen gas atmosphere with an oxygen concentration of 200 ppm under atmospheric pressure, with an integrated light intensity of 50 mJ / cm². 2 The irradiation was continued until a wrinkled shape was formed on the surface.

[0142] Next, as a third irradiation step, the coating film was irradiated with ionizing radiation to harden the entire coating film, thereby obtaining the decorative sheet of Example 1.

[0143] <Example 2> The particle size and amount of added particles were the same as in Example 1, but the coating amount was changed to 6 μm. Except for this change, the decorative sheet of Example 2 was obtained using the same method as in Example 1.

[0144] <Example 7> The particle size and amount of added particles were the same as in Example 1, but the coating amount was changed to 5 μm and the number of repetitions was changed to 9. Except for these changes, the decorative sheet of Example 7 was obtained using the same method as in Example 1.

[0145] <Example 8> The particle size and amount of added particles were the same as in Example 1, but the decorative sheet of Example 8 was obtained using the same method as in Example 1, except that the coating amount was changed to 10 μm.

[0146] <Example 9> The particle size of the added particles was the same as in Example 1, but the amount added was changed to 10 parts by mass and the coating amount to 5 μm. Except for these changes, the decorative sheet of Example 9 was obtained using the same method as in Example 1.

[0147] <Example 3> The decorative sheet 2, as described with reference to Figure 2, was manufactured by the method described in <Method for Manufacturing Decorative Sheet 2> above. In this case, the first protective layer 12 was formed in the same manner as in Example 7.

[0148] <Example 4> The decorative sheet 2, as described with reference to Figure 2, was manufactured by the method described in <Method for Manufacturing Decorative Sheet 2> above. In this case, the first protective layer 12 was formed in the same manner as in Example 8.

[0149] <Example 5> The decorative sheet 2, as described with reference to Figure 2, was manufactured by the method described in <Method for Manufacturing Decorative Sheet 2> above. In this case, the first protective layer 12 was formed in the same manner as in Example 1.

[0150] <Example 6> The decorative sheet 2, as described with reference to Figure 2, was manufactured by the method described in <Method for Manufacturing Decorative Sheet 2> above. In this case, the first protective layer 12 was formed in the same manner as in Example 2.

[0151] <Example 10> The decorative sheet 2, as described with reference to Figure 2, was manufactured by the method described in <Method for Manufacturing Decorative Sheet 2> above. In this case, the first protective layer 12 was formed in the same manner as in Example 9.

[0152] <Comparative Example 1> A decorative sheet for Comparative Example 1 was obtained in the same manner as in Example 1, except that an isocyanine curing agent was used as the thermosetting resin, and 40 parts by mass of general-purpose silica (amorphous) was added thereto.

[0153] <Comparative Examples 2-24> Decorative sheets were obtained in the same manner as in Comparative Example 1 by changing the amount of silica added and the thermal conditions.

[0154] The following evaluations were performed on each of the obtained decorative sheets.

[0155] (Rmr,Rdq) The Rmr (10%) and Rdq of the first protective layer were measured according to the method specified in JIS B 0601 (2013). The instrument used was a MITSUTOYO SURFTEST SJ-210.

[0156] (texture) (1) The warmth of wood When five people touched the decorative sheet, if three or more people felt the warmth of wood, it was classified as A; if one or two people felt the warmth of wood, it was classified as B; and if no one felt the warmth of wood, it was classified as C. Classification A was considered a passing grade.

[0157] (2) Design Based on the visual inspection of the decorative sheet by five people, a rating of A was given if three or more people felt it closely resembled the design of real wood, a rating of B if one or two people felt it closely resembled real wood, and a rating of C if no one felt it closely resembled real wood. A rating of B or higher was considered a passing grade.

[0158] (durability) (3) How easily fingerprints and smudges are visible The gloss level at 60 degrees was measured on the surface of each decorative sheet, and the resulting gloss level was defined as the initial gloss level. Next, the evaluation solution was applied to the surface protective layer, and the evaluation solution that adhered to the surface of the decorative sheet was wiped off. A higher fatty acid was used as the evaluation solution.

[0159] Subsequently, the glossiness at 60 degrees of the area where the evaluation solution was wiped off was measured, and the resulting glossiness was defined as the glossiness after wiping. The fingerprint removal rate was calculated using the following formula. Fingerprint removal rate (%) = (Glossiness after wiping / Initial glossiness) × 100 The evaluation criteria were as follows: A score of B or higher was considered a passing grade. A: 70% or more but less than 250% B: 50% or more but less than 70%, or 250% or more but less than 300% C: Less than 50%, or 300% or more.

[0160] (4) Stain resistance To evaluate stain resistance, a stain test A, as defined by the Japanese Agricultural Standards (JAS), was conducted. Lines 10 mm wide were drawn on the surface protective layer of each decorative sheet using blue ink, black quick-drying ink, and red crayon, and left for 4 hours. After that, the lines of blue ink, black quick-drying ink, and red crayon were wiped off with a cloth soaked in ethanol. The evaluation criteria were as follows. In the following evaluation criteria, A was considered a passing grade, and in the overall evaluation, B or higher was considered a passing grade. [Evaluation Criteria] A: I was able to easily wipe away the lines of each color. B: I was able to wipe away some of the lines of each color, but some stains remained. C: I was unable to wipe away the lines of each color.

[0161] [comprehensive evaluation] A: It received an A in all three types of stain resistance tests. B: At least one of the three types of stain resistance tests resulted in a B. C: At least one of the three types of stain resistance tests resulted in a C rating.

[0162] In the table below, "blue ink" refers to blue-black ink manufactured by PILOT, "Magic Ink" refers to quick-drying black ink manufactured by Teranishi Kogyo, and "red crayon" refers to red crayons manufactured by Pentel.

[0163] (5) Scratch resistance Each decorative sheet was attached to a wood substrate using a vinyl acetate-based adhesive. Then, the decorative sheet was rubbed back and forth 20 times with steel wool while applying a load of 100g, and any scratches or changes in gloss on the surface of the decorative sheet were visually inspected. The evaluation criteria were as follows: A score of B or higher was considered a passing grade. A: No scratches or changes in gloss occurred on the surface. B: Minor scratches or changes in gloss have occurred on the surface. C: Significant scratches or changes in gloss have occurred on the surface.

[0164] (6) Chemical resistance Each decorative sheet was attached to a wood substrate using a vinyl acetate-based adhesive. Then, 48% ethanol was dropped onto the surface of the decorative sheet and covered with a watch glass. After one hour, the watch glass was removed, the dripped area was wiped with cotton, and the extent of any remaining residue was checked. The evaluation criteria were as follows: A score of B or higher was considered a passing grade. A: No change in gloss was observed at all, and no whitening phenomenon was confirmed. B: A slight change in gloss was observed, or a slight whitening phenomenon was confirmed. C: A clear change in gloss was observed, or a significant whitening phenomenon was confirmed.

[0165] (7) Overall Durability Evaluation The evaluation criteria were as follows: A score of B or higher was considered a passing grade. A: Products that meet the requirements for fingerprint resistance, stain resistance, scratch resistance, and chemical resistance. B: Those who have passed two or three of the four examination items. C: Those who passed one or fewer of the four test items.

[0166] (8) Overall evaluation The evaluation criteria were based on three aspects: the warmth of the wood, the aesthetic appeal, and the physical properties of the coated paper. Products that passed all criteria were rated AA, those that passed two criteria were rated A, those that passed one or fewer criteria were rated B, and those that failed all criteria were rated C. Products that received even one C rating were given a one-level lower rating.

[0167] The evaluation results are shown in Tables 1-5.

[0168] [Table 1]

[0169] [Table 2]

[0170] [Table 3]

[0171] [Table 4]

[0172] [Table 5] [Explanation of Symbols]

[0173] 101, 102, 103, 104, 105: Decorative board, 10: Sheet substrate, 11: Pattern layer, 11a: Pattern ink layer, 11b: Conduit ink layer, 12: First protective layer, 13: Second protective layer, 8: Adhesive layer, 9: Substrate

Claims

1. A decorative sheet comprising, at least in this order, a pattern layer and a surface protection layer on one of the sheet base layers, The aforementioned decorative sheet has a wood grain pattern. The pattern layer comprises a pattern ink layer and a vascular ink layer that partially covers the pattern ink layer and represents the vascular tissue of the wood grain. The surface protection layer has a first protective layer in which at least a portion of the surface is exposed. The surface of the first protective layer has an uneven structure, The aforementioned uneven structure is a decorative sheet in which the load length ratio Rmr(10%) at a cutting level of 10% is 0.05 or more and 0.35 or less, and the root mean square slope Rdq is 0.15 or more and 0.4 or less.

2. The decorative sheet according to claim 1, wherein the thickness of the first protective layer is 2 μm or more and 10 μm or less.

3. The surface protective layer comprises the first protective layer and It comprises a second protective layer that covers a portion of the surface of the first protective layer and is laminated on the first protective layer, The decorative sheet according to claim 1 or 2, wherein the second protective layer is a layer with a higher gloss than the first protective layer.

4. The decorative sheet according to claim 3, wherein, in a plan view, the region in which the first protective layer is exposed and the conduit ink layer are in sync.

5. The decorative sheet according to claim 3, wherein, in a plan view, the region where the second protective layer is formed and the conduit ink layer are in sync.

6. The thickness of the first protective layer is 2 μm or more and 10 μm or less. The decorative sheet according to claim 3, wherein the sum of the thickness of the first protective layer and the thickness of the second protective layer is 3 μm or more and 30 μm or less.

7. A decorative sheet comprising, at least in this order, a pattern layer and a surface protection layer on one of the sheet base layers, The aforementioned decorative sheet has a wood grain pattern. The pattern layer comprises a pattern ink layer and a vascular ink layer that partially covers the pattern ink layer and represents the vascular tissue of the wood grain. The aforementioned surface protective layer comprises a first protective layer having an uneven surface structure, A second protective layer is provided between the patterned layer and the first protective layer, and covers the surface of the patterned layer. The first protective layer is laminated on the second protective layer, covering a portion of its surface, and the second protective layer is a layer with a higher gloss than the first protective layer. The aforementioned uneven structure is a decorative sheet in which the load length ratio Rmr(10%) at a cutting level of 10% is 0.05 or more and 0.35 or less, and the root mean square slope Rdq is 0.15 or more and 0.4 or less.

8. The decorative sheet according to claim 7, wherein, in a plan view, the region in which the second protective layer is exposed and the conduit ink layer are in sync.

9. The decorative sheet according to claim 7, wherein, in a plan view, the region where the first protective layer is formed and the conduit ink layer are in sync.

10. The thickness of the first protective layer is 2 μm or more and 10 μm or less. The decorative sheet according to any one of claims 7 to 9, wherein the thickness of the second protective layer and the sum of the thicknesses of the second protective layer are 3 μm or more and 30 μm or less.

11. The decorative sheet according to claim 1 or 7, wherein the glossiness of the first protective layer is less than 10.

12. The decorative sheet according to claim 1 or 7, wherein the first protective layer comprises a cured resin and particles.

13. The decorative sheet according to claim 12, wherein the average particle size of the particles is 3 μm or more.

14. The decorative sheet according to claim 12, wherein the average particle size of the particles is 3 μm or more and 10 μm or less.

15. The decorative sheet according to claim 12, wherein the content of the particles in 100 parts by mass of the resin is 3 parts by mass or more and 11 parts by mass or less.

16. The decorative sheet according to claim 12, wherein the resin is an ionizing radiation-curable resin.

17. The decorative sheet according to claim 16, wherein the ionizing radiation-curable resin is acrylate.

18. The acrylate is a trifunctional acrylate containing a repeating structure, The decorative sheet according to claim 17, wherein the number of repetitions of the repeating structure is 15 or more and 20 or less.

19. The acrylate is a tetrafunctional acrylate containing a repeating structure, The decorative sheet according to claim 17, wherein the number of repetitions of the repeating structure is 20 or more and 35 or less.

20. The decorative sheet according to claim 3, wherein the second protective layer comprises a two-component curable urethane resin containing a polyester polyol and an isocyanate compound.

21. The decorative sheet according to claim 1 or 7, wherein the sheet substrate layer is composed of a single layer of paper substrate.

22. The decorative sheet according to claim 1 or 7, wherein the sheet substrate layer comprises a first paper substrate, a moisture-proof resin layer, and a second paper substrate in that order.

23. A decorative panel comprising a decorative sheet as described in claim 1 or 7 and a substrate bonded together via an adhesive layer.

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