Decorative sheet and method for manufacturing decorative sheet

Abstract

Provided are: a decorative sheet having a glossiness of 15 or less, excellent designability, fingerprint resistance, high durability (particularly scratch resistance and stain resistance), and bending workability; and a method for producing the decorative sheet. A decorative sheet (1) according to the present embodiment is provided with a raw material layer (2) and a surface protection layer (5), the surface protection layer (5) having a glossiness of 15 or less, the surface protection layer (5) having ridges on the surface thereof and having uneven shapes formed thereon, the main material of the surface protection layer (5) being an ionizing radiation-curable resin, and the main material of the surface protection layer (5) being a non-ionizing radiation-curable resin. The main component of the ionizing radiation-curable resin is an acrylic resin including a repeating structure, the repeating structure being any one of an alkylene group, ethylene oxide, propylene oxide, and epsilon-caprolactone, and the acrylic monomer forming the acrylic resin has an acryloyl group in the range of 2-4 (inclusive). And a shaping parameter represented by the following formula 1 is in the range of 0.8 to 3.4 inclusive. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a decorative sheet used for interior and exterior decoration of buildings, surface decoration of doors and windows, furniture, construction materials, floor materials, etc., and a method for manufacturing the decorative sheet. Background Art

[0002] In the above-mentioned buildings, in order to give the surface of the decorative sheet design and durability, it is generally made into a decorative board by sticking it on the surface of wood, wooden board, metal board, non-combustible board, paper substrate or resin substrate through an adhesive, and is widely used.

[0003] Regarding the design, we can choose from various printing methods to create patterns such as wood grain or stone grain, or plain color surfaces without patterns, depending on the requirements and use. Similarly, the glossiness of the surface is also an important factor in design, and we can choose from high gloss like a mirror surface to low gloss without any reflection, depending on the requirements and use.

[0004] In addition, as mentioned above, the function of the decorative sheet that is equally important as the design is to impart durability. Durability is a comprehensive evaluation of scratch resistance and stain resistance, and whether these properties can be ensured continuously for a long time. The requirements vary depending on the environment and conditions in which the decorative sheet is used, but a decorative sheet with high performance is always required.

[0005] In order to impart durability, a surface protection layer is generally formed on the outermost surface of the decorative sheet. In addition, in order to adjust the glossiness, especially to achieve low glossiness, a gloss adjuster (matt additive) is generally added to the surface protection layer.

[0006] Furthermore, since the decorative sheet is generally subjected to processing such as cutting and bending in order to form a decorative plate or a decorative material, it is preferable that the decorative sheet has processability that can withstand such processing.

[0007] As described above, as a decorative sheet that takes design properties (low gloss), scratch resistance, and stain resistance into consideration, there is a decorative sheet described in Patent Document 1, for example.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-119138 Summary of the invention

[0011] Problems to be solved by the invention

[0012] In recent years, as the use of decorative plates using decorative sheets has expanded and consumers have become more aware of quality, low gloss (glossiness of 15 or less) and a combination of fingerprint resistance, scratch resistance, stain resistance, and bendability are required.

[0013] In response to the above requirements, one method of reducing gloss is to add a gloss adjuster at a high concentration to roughen the surface. However, adding a large amount of gloss adjuster may cause the following disadvantages.

[0014] (1) Fingerprints and dirt are difficult to remove, and fingerprint resistance is reduced. (2) The gloss modifier is detached during the scratch resistance test, and the scratch resistance is reduced. (3) Dirt is difficult to remove, and the stain resistance is reduced. (4) During bending, whitening occurs due to the gloss modifier, and the bending processability is reduced.

[0015] In order to solve the above-mentioned problems, the purpose of the present invention is to provide a decorative sheet and a method for manufacturing the same which has low gloss (glossiness of 15 or less), i.e., excellent design, fingerprint resistance, high durability (especially scratch resistance and stain resistance), and processability (especially bending processability).

[0016] Means for solving problems

[0017] The inventors have found that in order to achieve low gloss, by optimizing the concavo-convex shape of the surface protective layer and further repeatedly experimenting with the materials used for the surface protective layer to find the necessary structural elements, it is possible to provide a decorative sheet and a method for manufacturing the same that has low gloss and exhibits fingerprint resistance, high durability (especially scratch resistance and stain resistance) and processability (especially bending processability).

[0018] In order to solve the problem, one embodiment of the present invention involves a decorative sheet comprising a raw material layer and a surface protective layer arranged on one surface of the raw material layer, the glossiness of the surface protective layer is less than 15, the surface protective layer has a ridge portion arranged in a ridge-like protrusion on its surface, and is formed with a concave-convex shape, the main material of the surface protective layer is an ionizing radiation curing resin, the main component of the ionizing radiation curing resin is an acrylic resin containing a repeating structure, the repeating structure is any one of the structures of alkylene, ethylene oxide, propylene oxide and ε-caprolactone, the acrylic monomer forming the acrylic resin has an acryloyl group in the range of 2 to 4, and the excipient parameter represented by the following formula 1 is in the range of 0.8 to 3.4.

[0019] [Mathematical formula 1]

[0020]

[0021] It should be noted that in Formula 1, "the number of functional groups" refers to the number of acryloyl groups (functional groups) possessed by the acrylic monomer, and "the chain length between acryloyl groups" refers to the total number of carbon atoms and oxygen atoms between the carbonyl carbons connecting the acryloyl groups possessed by the acrylic monomer. It should be noted that "the chain length between acryloyl groups" does not include the number of methyl carbons branched midway like propylene oxide. That is, "the chain length between acryloyl groups" refers to the number of atoms between the shortest connecting acryloyl groups. In addition, in the case where the acrylic monomer has more than 3 acryloyl groups, the largest value is selected from the combination of all the chain lengths between acryloyl groups, and this value (number of atoms) is set as the "chain length between acryloyl groups" in Formula 1.

[0022] In addition, in the case where the acrylic monomer has only one acryloyl group, the "chain length between acryloyl groups" refers to the maximum value of the sum of the number of carbon atoms and the number of oxygen atoms connecting from the terminal atom other than hydrogen at the other end of the acrylic monomer not having an acryloyl group to the carbonyl carbon of the acryloyl group. That is, in the case where there is one acryloyl group, the "chain length between acryloyl groups" is determined (measured) by counting the number of carbon atoms and oxygen atoms from the single-bonded oxygen adjacent to the acryloyl group to the end of the monomer.

[0023] Effects of the Invention

[0024] According to one embodiment of the present invention, a decorative sheet having low gloss (glossiness of 15 or less) and having fingerprint resistance, scratch resistance, stain resistance, and bendability, and a method for producing the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] [ Figure 1 ] is a schematic cross-sectional view illustrating the structure of the decorative sheet involved in an embodiment of the present invention.

[0026] [ Figure 2 ] is a schematic cross-sectional view illustrating a structure of a surface protection layer of a decorative sheet involved in an embodiment of the present invention.

[0027] [ Figure 3 ] is a plan photograph showing a structural example of the surface of the surface protection layer of the decorative sheet involved in an embodiment of the present invention.

[0028] [ Figure 4 ] is a schematic cross-sectional view illustrating the cross-sectional shape of the ridge portion involved in an embodiment of the present invention.

[0029] [ Figure 5 ] is a schematic diagram illustrating the temporal variation of the irradiation light amount of each irradiation light in the manufacturing process of the decorative sheet involved in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Hereinafter, the configuration of a decorative sheet according to an embodiment of the present invention will be described with reference to the drawings.

[0031] Here, the drawings are schematic, and the relationship between thickness and plane size, the ratio of thickness of each layer, etc. are different from the actual situation. In addition, the embodiments shown below illustrate the configuration for concretizing the technical idea of ​​the present invention, and the technical idea of ​​the present invention can be variously modified within the technical scope specified by the claim items recorded in the claims.

[0032] (constitute)

[0033] like Figure 1 As shown, the decorative sheet 1 of this embodiment is composed of a pattern layer 3, an adhesive layer 7 (thermosensitive adhesive layer, anchor coating, dry lamination adhesive layer), a transparent resin layer 4 and a surface protection layer 5 stacked in sequence on one side, i.e., the surface side, of the raw material layer (base material layer) 2. In addition, a concealing layer 8 and a primer layer 6 are provided on the other side, i.e., the back side, of the raw material layer 2. The pattern layer 3, the adhesive layer 7, the transparent resin layer 4, the concealing layer 8 and the primer layer 6 may also be omitted.

[0034] Then, if Figure 1 As shown, the decorative sheet 1 of this embodiment is attached to a substrate B to form a decorative material 11. The substrate B is not particularly limited, and may be made of, for example, a wooden board, an inorganic board, a metal board, or a composite board made of a plurality of materials.

[0035] <Raw material layer 2>

[0036] As the raw material layer 2, for example, a material selected arbitrarily from paper, synthetic resin, or synthetic resin foam, rubber, non-woven fabric, synthetic paper, metal foil, etc. can be used. As paper, thin leaf paper, titanium paper, resin-impregnated paper, etc. can be exemplified. As synthetic resin, polyethylene, polypropylene, polybutene, polystyrene, polycarbonate, polyester, polyamide, ethylene-vinyl acetate copolymer, polyvinyl alcohol, acrylic acid, etc. can be exemplified. As rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-butadiene copolymer rubber, styrene-isoprene-styrene block copolymer rubber, styrene-butadiene-styrene block copolymer rubber, polyurethane, etc. can be exemplified. As non-woven fabric, organic or inorganic non-woven fabric can be used. As metal of metal foil, aluminum, iron, gold, silver, etc. can be exemplified.

[0037] When an olefin resin is used as the raw material layer 2, since the surface of the raw material layer 2 is mostly inert, it is preferred to provide a primer layer 6 between the raw material layer 2 and the substrate B. In addition, in order to improve the adhesion between the raw material layer 2 composed of an olefin material and the substrate B, the raw material layer 2 may be subjected to surface modification treatments such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, and dichromic acid treatment.

[0038] As the primer layer 6, the same material as the pattern layer 3 described later can be used. Since the primer layer 6 is applied to the back side of the decorative sheet 1, when the decorative sheet 1 is wound in a web shape, in order to avoid sticking and improve the adhesion with the adhesive, an inorganic filler can be added to the primer layer 6. Examples of the inorganic filler include silicon dioxide, aluminum oxide, magnesium oxide, titanium oxide, barium sulfate, and the like.

[0039] Taking printing workability, cost, and the like into consideration, the thickness of the original material layer 2 is preferably within a range of 20 μm to 250 μm.

[0040] <Pattern layer 3>

[0041] The pattern layer 3 is a pattern printing layer obtained by applying ink to the raw material layer 2. As a binder for the ink, for example, it can be appropriately selected and used from each or each modified substance such as nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc. The binder can be any of water-based, solvent-based, and emulsion-based, and can also be a one-component type or a two-component type using a curing agent. In addition, a method of using a curable ink and curing the ink by irradiation with ultraviolet rays or electron beams can also be adopted. Among them, the most common method is a method of using a carbamate-based ink and curing it by isocyanate. For the pattern layer 3, in addition to the binder, for example, colorants such as pigments and dyes contained in ordinary inks, body pigments, solvents, various additives, etc. can be added. As pigments with high versatility, for example, pearl pigments such as condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolones, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and mica can be listed.

[0042] In addition to ink coating, the pattern layer 3 can also be designed by vapor deposition or sputtering of various metals. In particular, it is preferable to add a light stabilizer to the ink, thereby suppressing the degradation of the decorative sheet 1 itself caused by light degradation of the ink and extending the life of the decorative sheet 1.

[0043] <Adhesive layer 7>

[0044] The adhesive layer 7 is also called a heat-sensitive adhesive layer, an anchor coating layer, or a dry lamination adhesive layer.

[0045] The resin material of the adhesive layer 7 is not particularly limited, and for example, it can be appropriately selected and used from resin materials such as acrylic acid, polyester, polyurethane, and epoxy. In addition, as the resin material of the adhesive layer 7, for example, an ethylene-vinyl acetate copolymer resin adhesive can also be used. The coating method can be appropriately selected according to the viscosity of the adhesive, etc., and a gravure coater is usually used. After being coated on the pattern layer 3 by the gravure coater, it is laminated with the transparent resin layer 4. It should be noted that, when the bonding strength between the transparent resin layer 4 and the pattern layer 3 is fully obtained, the adhesive layer 7 can be omitted.

[0046] <Transparent resin layer 4>

[0047] As the resin material of the transparent resin layer 4, an olefin resin is preferably used. As the olefin resin, for example, in addition to polypropylene, polyethylene, polybutene, etc., alpha olefins (for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1 Polymers obtained by homopolymerization of ethylene-1-olefins or copolymerization of two or more monomers such as ethylene-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.; copolymers obtained by copolymerizing ethylene or α-olefins with other monomers such as ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-methyl methacrylate copolymers, ethylene-ethyl methacrylate copolymers, ethylene-butyl methacrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, and ethylene-butyl acrylate copolymers.

[0048] In addition, in order to improve the surface strength of the decorative sheet 1, highly crystalline polypropylene is preferably used as the resin of the transparent resin layer 4. It should be noted that various additives such as (for example) heat stabilizers, light stabilizers, anti-blocking agents, catalyst scavengers, colorants, light scattering agents, and gloss regulators may be added to the transparent resin layer 4 as needed. As heat stabilizers, phenolic, sulfur, phosphorus, hydrazine, etc. are generally added in any combination, and as light stabilizers, hindered amines, etc. are generally added in any combination.

[0049] <Surface protection layer 5>

[0050] The surface protection layer 5 has a core portion 5A and a ridge portion 5B provided to protrude in a ridge shape from one surface of the core portion 5A. Thus, a concavo-convex shape is formed on the surface of the surface protection layer 5 .

[0051] Here, in the decorative sheet 1 according to the present embodiment, "ridge" refers to a shape that is slenderly raised and connected in a linear shape in a plan view. The ridge portion 5B may be curved or linear in a plan view, but is preferably curved from the viewpoint of the anti-fingerprint property of the surface of the decorative sheet 1. In the present disclosure, the ridge portion 5B is, for example, a portion from the lowest part to the top of the concave-convex shape provided on the surface of the surface protection layer 5, and the core portion 5A refers to the portion of the surface protection layer 5 other than the ridge portion 5B.

[0052] Figure 2 2 is a cross-sectional view schematically showing a cross section of a ridge portion 5B of the surface protection layer 5 (a cross section in the thickness direction of the surface protection layer 5 ). Figure 3 : is a plan view showing the structure of the surface of the surface protection layer 5. Here, Figure 3 This is a plane photograph obtained using a laser microscope (OLS-4000 manufactured by Olympus Corporation).

[0053] like Figure 3 As shown in the plan view of FIG. 5 , the ridge 5B is a shape that is elongated and connected in a linear manner in a plan view. As described later, the ridge 5B is formed by irradiating the surface of the ionizing radiation curing resin with light of a specific wavelength to deform the surface of the ionizing radiation curing resin.

[0054] The shape of the ridge 5B can be determined by the lateral direction (the plane direction of the surface protection layer 5). Figure 2 The surface roughness index RSm (μm) is expressed as the surface roughness index RSm (μm) and RSm is preferably 300 or less. More preferably, it is 250 or less. When RSm is greater than 300, the ridges may not have low gloss because the intervals are too wide.

[0055] In addition, RSm is more preferably 200 or less. When RSm is within this numerical range, the intervals between the ridges are appropriately wide, so the affinity for water or detergent (water containing a surfactant or alcohol) is sufficiently good. Therefore, when the decorative sheet has RSm within this numerical range, even when the surface of the decorative sheet is contaminated, it is easy to wipe the dirt with water or detergent.

[0056] In addition, RSm is most preferably 150 or less. If RSm is within this numerical range, the surface roughness of the surface protection layer 5 is close to that of a general commercially available cleaning sponge. Therefore, the cleaning sponge can easily enter between the ridges, and even if the surface of the decorative sheet is contaminated, it is easy to wipe the dirt with a general commercially available cleaning sponge.

[0057] Here, RSm is a value measured by a line roughness meter (based on JIS B0601).

[0058] The cross-sectional shape of the surface protection layer 5 in the thickness direction of the ridge portion 5B may be a sinusoidal wave shape.

[0059] Here, if Figure 4 As shown in FIG. 1 , the “sine wave shape” means that the shape of a line from the lowest position C to the highest position (apex) D of the ridge portion 5B can be expressed by a sine wave.

[0060] Next, the mechanism of forming the ridge portion 5B will be described.

[0061] When acrylate is irradiated with light having a wavelength of 200 nm or less as the first irradiation light, acrylate can be self-excited. Therefore, by irradiating acrylate with light having a wavelength of 200 nm or less, acrylate can be cross-linked. Light having a wavelength of 200 nm or less reaches a depth of about tens to hundreds of nm in acrylate. Therefore, only the surface is cross-linked, and the portion below it still has fluidity, thus generating fine concavo-convex shapes connected in a wave shape like folded folds.

[0062] In the surface protection layer 5 formed in this way, there is no interface between the core portion 5A and the ridge portion 5B, and the core portion 5A and the ridge portion 5B are formed in a state of being integrally continuous.

[0063] Light below 200 nm is absorbed by oxygen in the atmosphere and is greatly attenuated. Therefore, when processing acrylate, it is necessary to introduce nitrogen to control the reaction atmosphere. The residual oxygen concentration in the reaction atmosphere is preferably suppressed to less than 2000 ppm. The residual oxygen concentration in the reaction atmosphere is more preferably less than 1000 ppm.

[0064] In order to generate the concavo-convex shape by using the light with a wavelength of 200 nm or less as the first irradiation light, the integrated light amount of the first irradiation light is preferably set to 0.1 mJ / cm 2 Above 200mJ / cm 2 The cumulative light intensity is more preferably 0.5 mJ / cm 2 Above 100mJ / cm 2 The cumulative light intensity is more preferably 10 mJ / cm 2 Above 50mJ / cm 2 The most preferred cumulative light intensity is 20 mJ / cm2 Above 30mJ / cm 2 When the accumulated light intensity is less than 0.1mJ / cm 2 In the case of , the curing reaction is weak and the concavo-convex shape cannot be fully formed, so the gloss will not be reduced. 2 In this case, the curing reaction becomes too strong and the surface condition deteriorates.

[0065] Light below 200nm can be extracted from excimer VUV light. Excimer VUV light can be generated by a lamp of a rare gas or a rare gas halide. When electrons with high energy are applied from the outside to a lamp enclosing a gas of a rare gas or a rare gas halide, a large amount of discharge plasma (dielectric barrier discharge) is generated. Through this plasma discharge, the atoms of the discharge gas (rare gas) are excited and instantly become an excimer state. When returning to the ground state from the excimer state, light of a wavelength region unique to the excimer is emitted.

[0066] The gas used for the excimer lamp can be any gas used in the past as long as it emits light below 200nm. As the gas, rare gases such as Xe, Ar, and Kr, and mixed gases of rare gases such as ArBr and ArF and halogen gases can be used. The wavelength (center wavelength) of the excimer lamp varies depending on the gas, for example, it has a wavelength of about 172nm (Xe), about 126nm (Ar), about 146nm (Kr), about 165nm (ArBr), about 193nm (ArF), etc.

[0067] However, considering the size of the photon energy obtained, the difference in wavelength and the binding energy of the organic matter, it is preferred to use a xenon lamp as a light source that emits excimer light with a central wavelength of 172nm. In addition, if the cost and material acquisition etc. spent on equipment maintenance are also considered, it is preferred to use a xenon lamp as a light source.

[0068] Since the light with a wavelength of 200 nm or less as the first irradiation light can only reach a depth of about tens to hundreds of nm from the outermost surface in the acrylic, the inside of the surface protection layer 5 having the ridge 5B formed by irradiation with light of 200 nm or less still has fluidity, and a curing reaction must be further performed. In order to cure the surface protection layer 5 after irradiation with light of 200 nm or less, ionizing radiation or UV light with a longer wavelength than the first irradiation light, i.e., light with a wavelength of 200 nm or less, can be used as the second irradiation light.

[0069] It should be noted that in the present embodiment, for example, after the irradiation of the second irradiation light, ionizing radiation of a different type from the second irradiation light or UV light having a longer wavelength than the second irradiation light may be irradiated as the third irradiation light, but it is preferred that the surface protection layer 5 having the ridge portion 5B is formed by irradiating only the first irradiation light and the second irradiation light. It should be noted that the third irradiation light may be irradiated in the case where the strength of the surface protection layer 5 is insufficient when only the second irradiation light is irradiated.

[0070] In order to cure the entire surface protection layer 5 by irradiating the second irradiation light, the integrated light amount of the second irradiation light is preferably set to 0.1 mJ / cm 2 Above 200mJ / cm 2 The cumulative light intensity is more preferably 0.5 mJ / cm 2 Above 100mJ / cm 2 The cumulative light intensity is more preferably 10 mJ / cm 2 Above 50mJ / cm 2 When the accumulated light intensity is less than 0.1mJ / cm 2 In the case of , the curing reaction is weak and the entire surface protection layer 5 cannot be sufficiently strengthened, so the scratch resistance tends to decrease. In addition, when the cumulative light amount is greater than 200mJ / cm 2 In the case of , the curing reaction becomes too strong and the surface state tends to deteriorate.

[0071] In addition, the cumulative light amount of the second irradiation light is preferably greater than the cumulative light amount of the first irradiation light. The cumulative light amount of the second irradiation light is preferably 1.1 times or more and 3.0 times or less of the cumulative light amount of the first irradiation light, and more preferably 1.5 times or more and 2.0 times or less. When the cumulative light amount of the second irradiation light is less than 1.1 times the cumulative light amount of the first irradiation light, the curing reaction is weak and it may not be possible to give sufficient strength to the entire surface protection layer 5. In addition, when the cumulative light amount of the second irradiation light exceeds 3.0 times the cumulative light amount of the first irradiation light, the curing reaction of the entire surface protection layer 5 becomes too strong, and the shape of the ridge 5B may be deformed.

[0072] Below, refer to Figure 5 The temporal change in the irradiation light amount of the first irradiation light and the temporal change in the irradiation light amount of the second irradiation light will be described.

[0073] Figure 5 It is a diagram schematically showing the time change of the irradiation light amount of the first irradiation light and the time change of the irradiation light amount of the second irradiation light.

[0074] Figure 5 (a), (c), (e), (g), and (i) are diagrams schematically showing the temporal change in the irradiation light amount of the first irradiation light. Figure 5(b), (d), (f), (h), and (j) are diagrams schematically showing the temporal change in the irradiation light amount of the second irradiation light.

[0075] like Figure 5 As shown in (a), the irradiation light intensity of the first irradiation light may gradually increase as the irradiation time elapses, and then gradually decrease as the irradiation time elapses. Figure 5 As shown in (c), the irradiation light intensity of the first irradiation light may also gradually decrease as the irradiation time elapses. Figure 5 As shown in (e), the irradiation light intensity of the first irradiation light may also gradually increase as the irradiation time elapses. Figure 5 As shown in (g), the irradiation light intensity of the first irradiation light may gradually decrease as the irradiation time elapses, and then gradually increase as the irradiation time elapses. Figure 5 As shown in (i), the irradiation light amount of the first irradiation light may be constant from the start of irradiation to the end of irradiation.

[0076] like Figure 5 As shown in (b), the irradiation light intensity of the second irradiation light may gradually increase as the irradiation time elapses, and then gradually decrease as the irradiation time elapses. Figure 5 As shown in (d), the irradiation light intensity of the second irradiation light may also gradually decrease as the irradiation time elapses. Figure 5 As shown in (f), the irradiation light intensity of the second irradiation light may also gradually increase as the irradiation time elapses. Figure 5 As shown in (h), the irradiation light intensity of the second irradiation light may gradually decrease as the irradiation time elapses, and then gradually increase as the irradiation time elapses. Figure 5 As shown in (j), the irradiation light amount of the second irradiation light may be constant from the start of irradiation to the end of irradiation.

[0077] In addition, in this embodiment, Figure 5 The irradiation mode of the first irradiation light shown in (a), (c), (e), (g) and (i) is the same as Figure 5 The irradiation methods of the second irradiation light shown in (b), (d), (f), (h) and (j) may be used in combination as appropriate. Figure 5 (a) The irradiation mode of the first irradiation light and Figure 5 (f) The second irradiation light irradiation method shown in FIG. Figure 5 (g) The irradiation mode of the first irradiation light and Figure 5 (f) The second irradiation light irradiation method shown in FIG. 1 is used in combination. It should be noted that when the value of RSm is set to a more preferred range of 300 or less, Figure 5(e) The irradiation mode of the first irradiation light and Figure 5 The irradiation method of the second irradiation light shown in (d) is used in combination.

[0078] As described above, the ridge 5B formed by irradiating light with a wavelength of 200 nm or less has a fine structure compared to the concavo-convex shape formed by mechanical processing such as embossing on the surface of the surface protection layer 5. By forming such a fine concavo-convex shape on the surface of the surface protection layer 5, the anti-fingerprint property can be improved while maintaining the matte feeling of the surface of the decorative sheet 1.

[0079] The thickness of the surface protection layer 5 is preferably set within a range of 2 μm to 20 μm. The thickness of the surface protection layer 5 is more preferably within a range of 5 μm to 20 μm. The thickness of the surface protection layer 5 is further preferably within a range of 8 μm to 15 μm. The thickness of the surface protection layer 5 is most preferably within a range of 10 μm to 12 μm. When the thickness of the surface protection layer 5 is set to less than 2 μm, deep shaping cannot be performed using vacuum ultraviolet light, and low gloss cannot be achieved. In addition, when the thickness of the surface protection layer 5 is set to greater than 20 μm, processability is reduced, and whitening occurs during bending.

[0080] The thickness of the surface protection layer 5 is preferably set so that the ratio of the thickness of the ridge portion 5B to the thickness of the core portion 5A (thickness of the ridge portion 5B / thickness of the core portion 5A) is greater than 0.01 and less than 2.0, and more preferably greater than 0.1 and less than 1.0.

[0081] Here, the pattern layer 3 and the surface protection layer 5 can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, inkjet printing, etc. In addition, since the surface protection layer 5 covers the entire surface side of the raw material layer 2, it can also be formed by various coating methods such as roller coating, blade coating, micro gravure coating, die coating, etc. These printing methods or coating methods can be selected separately according to the layers to be formed, or the same method can be selected for processing.

[0082] From the viewpoint of design, the pattern layer 3 and the surface protection layer 5 can be synchronized. When they are synchronized, the surface protection layer 5 needs to be formed together after the pattern layer 3 is formed, so it is preferable to use the gravure printing method. In addition, since the gravure printing method can be printed at a relatively high speed, it is also advantageous in terms of cost and is preferred. Here, synchronization means that more than 50%, preferably more than 70%, and most preferably more than 90% of the portion where the surface protection layer 5 is formed overlaps with the pattern portion of the pattern layer 3 in a plan view.

[0083] In order to adjust the thickness of the surface protection layer 5, the coating amount can be adjusted in the above-mentioned printing method and coating method. In various printing methods and coating methods, the coating amount can be calculated based on the quality difference between the decorative sheet formed with the surface protection layer and the decorative sheet without the surface protection layer on the substrate (raw material layer).

[0084] The main material of the surface protection layer 5 is an ionizing radiation curable resin. Here, the main material refers to: relative to 100 parts by mass of the surface protection layer, it contains more than 60 parts by mass, more preferably more than 70 parts by mass, and most preferably more than 80 parts by mass. As the ionizing radiation curable resin constituting the surface protection layer 5, known resins such as various monomers or commercially available oligomers can be used, for example, (methyl) acrylic resins, silicone resins, polyester resins, carbamate resins, amide resins, and epoxy resins can be used. The ionizing radiation curable resin can be any one of an aqueous resin or a non-aqueous (organic solvent) resin. Among these resins, as the ionizing radiation curable resin constituting the surface protection layer 5, the main component is most preferably an acrylic resin containing a repeating structure.

[0085] The main component of the ionizing radiation curable resin constituting the surface protection layer 5 is a resin obtained by polymerizing an acrylate monomer having 2 to 4 acryloyl groups. As the above-mentioned acrylate monomer, for example, trimethylolpropane triacrylate, glycerol triacrylate, isocyanurate triacrylate, pentaerythritol triacrylate, etc. can be used. It should be noted that when trimethylolpropane triacrylate is used as the main component of the ionizing radiation curable resin constituting the surface protection layer 5, even if the cumulative light amount of the first irradiation light is low (for example, even if the cumulative light amount is 0.1 mJ / cm 2 This is believed to be because trimethylolpropane triacrylate has a relatively high absorbance (absorption coefficient) for the first irradiation light, i.e., light with a wavelength of 200 nm or less.

[0086] Here, the main component means that 70 parts by mass or more, more preferably 80 parts by mass or more, and most preferably 90 parts by mass or more are contained with respect to 100 parts by mass of the constituent resin component.

[0087] When gravure printing is used as a coating method, the suitable viscosity range of the ionizing radiation curable resin is 10 to 500 mPa·s, and the optimal viscosity range is 100 to 200 mPa·s. In addition, most resins having a skeleton that causes hydrogen bonding or π-π stacking have a high viscosity of more than 500 mPa·s, and are not preferred as ionizing radiation curable resins of this embodiment. In addition, in order to adjust the viscosity, an organic solvent or a low-viscosity 1-functional acrylate resin can be added. However, from the perspective of environmental load, it is preferred not to use an organic solvent.

[0088] Therefore, from the viewpoint of production process, when a monofunctional acrylate resin is added to a trifunctional or higher-functional acrylate resin and used, the content of the monofunctional acrylate resin is preferably in the range of 10% by mass to 30% by mass, and more preferably in the range of 15% by mass to 20% by mass, of the content (mass) of the difunctional or higher-functional acrylate resin.

[0089] The acrylate monomer used for polymerizing the main component of the above-mentioned ionizing radiation curable resin has any one of an alkylene structure, an ethylene oxide (EO) structure, a propylene oxide (PO) structure, and an ε-caprolactone (CL) structure. Since the molecules of the ethylene oxide structure, the propylene oxide structure, and the ε-caprolactone structure can rotate freely and have high flexibility, the stress required for the wrinkle deformation for shaping is reduced in the surface cured layer formed by irradiation with light below 200nm. Therefore, it is easy to form fine concavoconvex shapes in the surface cured layer (the surface layer of the surface protective layer), so it is more preferred.

[0090] The chain length between the acryloyl groups of the monomers constituting the ionizing radiation curable resin (the main component of the ionizing radiation curable resin) having the above-mentioned repeating structure is measured by counting the carbon number and oxygen number starting from the single bond oxygen adjacent to the acryloyl group and up to the single bond oxygen adjacent to a different acryloyl group. In the case where there is a branch between the acryloyl groups, the number of atoms in the branch is not counted, and the shortest distance is counted. In addition, in the case where the acryloyl group is trifunctional or more, the chain when the chain length between the acryloyl groups becomes the maximum is defined as the maximum chain length between the acryloyl groups.

[0091] When there is one acryloyl group, the number of carbon atoms and oxygen atoms from the single-bonded oxygen adjacent to the acryloyl group to the terminal of the monomer is measured.

[0092] When calculating the ratio of the number of acryloyl groups (number of functional groups) and the maximum chain length between acryloyl groups (chain length between acryloyl groups) as a shaping parameter, there is a scaling problem. Therefore, in this embodiment, the number of acryloyl groups (number of functional groups) is divided by 6, and the maximum chain length between acryloyl groups is divided by 100, and the resulting value is defined as the shaping parameter (see Formula 1 below).

[0093] [Mathematical formula 2]

[0094]

[0095] Hereinafter, a method for determining the "maximum chain length between acryloyl groups (chain length between acryloyl groups)" in the present embodiment will be described.

[0096] For example, when a monomer represented by the following structural formula is used as the acrylate monomer involved in the present embodiment, by counting the carbon atoms of the carbonyl carbon connected to the arrow, the "inter-acryloyl chain length" is "10". In addition, the number of functional groups of the monomer represented by the following structural formula is "2".

[0097] [Chemical formula 1]

[0098]

[0099] In addition, for example, when a monomer represented by the following structural formula is used as another acrylate monomer involved in this embodiment, by counting the carbon and oxygen atoms of the carbonyl carbon connected by the arrow, the "inter-acryloyl chain length" is "39". Here, since the methyl group in the middle is not the shortest path, it is not counted. In addition, the number of functional groups of the monomer represented by the following structural formula is "2".

[0100] [Chemical formula 2]

[0101]

[0102] In addition, for example, when a monomer represented by the following structural formula is used as the other acrylate monomer involved in the present embodiment, by counting the carbon and oxygen atoms of the carbonyl carbon connected by the arrow, the "inter-acryloyl chain length" is "25". In addition, the number of functional groups of the monomer represented by the following structural formula is "3".

[0103] [Chemical formula 3]

[0104]

[0105] The properties of the resin are affected by the above-mentioned shaping parameters. The more the number of acryloyl groups, the higher the degree of crosslinking, the shorter the maximum chain length of the monomer, the higher the density of the resin, the improved scratch resistance, but the processability is reduced. Therefore, when the shaping parameter is a value greater than 3.4, the shaping cannot be fully performed, which is not preferred. In addition, when the shaping parameter is less than 0.8, the glossiness is sufficiently reduced, but the resin softens. Therefore, the scratch resistance is reduced, which is not preferred.

[0106] Therefore, the shaping parameter range that can shape the decorative sheet and simultaneously achieve scratch resistance and processability that are preferable for the surface protection layer of the decorative sheet is 0.8 or more and 3.4 or less.

[0107] If the shaping parameter is 0.8 or more and 3.4 or less, the surface protection layer of the decorative sheet can have the preferred characteristics. Preferably, the number of acryloyl groups (number of functional groups) is 3 or 4, and the shaping parameter is 1.0 or more and 2.0 or less. When the number of acryloyl groups (number of functional groups) is 1 or less or 5 or more, a slight roughness (surface unevenness) may be generated on the shaping surface, which is not preferred.

[0108] The above-mentioned excipient parameter can be calculated by analyzing the molecular structure of the main component of the ionizing radiation curable resin, and the above-mentioned formula 1 is applied to the molecular structure. As the analytical method of the main component of the above-mentioned ionizing radiation curable resin, NMR, MALDI-TOF-MS, IR etc. can be used. Ionizing radiation curable resin sometimes has a molecular weight distribution due to the difference of the number of repetitions of the repeating structure. In the case of having a molecular weight distribution, the material with the molecular weight of the strongest peak in the MALDI-TOF-MS mass spectrum is used as the main component. That is, in the case of having a molecular weight distribution, the repetition number is set to the repetition number corresponding to the molecular weight with the strongest peak in the MALDI-TOF-MS mass spectrum.

[0109] The surface protection layer 5 may contain particles. By adding particles with an optimal particle size and an optimal content, a uniform surface can be formed. As particles, for example, organic materials such as PE wax, PP wax, resin beads, or inorganic materials such as silica, glass, aluminum oxide, titanium dioxide, zirconium oxide, calcium carbonate, and barium sulfate can be used. The average particle size (D50) of the particles is preferably 10 μm or less. More preferably, it is 1 μm to 8 μm, further preferably 2 μm to 6 μm, and most preferably 4 μm to 5 μm. In the case of more than 10 μm, the scratch resistance is reduced due to the shedding of particles, so it is not preferred. In the case of less than 1 μm, the effect of making the surface uniform is small, so it is not preferred.

[0110] In addition, the amount of particles added is preferably 0.5 to 10 parts by mass relative to 100 parts by mass of the ionizing radiation curable resin. The amount of particles added is more preferably 2 to 8 parts by mass, further preferably 2 to 6 parts by mass, and most preferably 4 to 5 parts by mass. The surface protection layer 5 is preferably formed into a uniform surface state by containing the above-mentioned amount of particles.

[0111] Here, "particle size (average particle size)" may be a value (average value) obtained by measuring the particle size distribution of the particles used; or it may be a value obtained by observing the cross section of the obtained decorative material, measuring the particle sizes of multiple particles and averaging them. The two measurement methods are different from each other, but the obtained particle size values ​​are substantially the same. For example, the average particle size of the particles added to the surface protection layer 5 may be the median particle size (D50) measured by a laser diffraction / scattering particle size distribution measuring device.

[0112] When the entire surface protection layer 5 is cured by UV light, a photoinitiator needs to be added to the surface protection layer 5. The photoinitiator is not particularly limited, and examples thereof include benzophenone-based, acetophenone-based, benzoin ether-based, and thioxanthone-based photoinitiators.

[0113] In order to impart the required functions, functional additives such as antibacterial agents and mildewproof agents may be added to the surface protection layer 5. In addition, ultraviolet absorbers and light stabilizers may be added to the surface protection layer 5 as required. As ultraviolet absorbers, for example, benzotriazole series, benzoate series, benzophenone series, triazine series, etc. are usually added in any combination, and as light stabilizers, for example, hindered amine series, etc. are usually added in any combination.

[0114] Although such a decorative sheet 1 does not contain a gloss regulator (matting additive), the glossiness is less than 15, which is a decorative sheet with extremely low glossiness. In conventional decorative sheets, when the glossiness of a decorative sheet having a surface protective layer is less than 8, the content of the gloss regulator in the surface protective layer is high, and the surface protective layer becomes turbid. Therefore, the color and pattern of the colored pattern layer may not be clearly expressed, or the design of the decorative sheet may be reduced. In addition, in the case of obtaining a decorative sheet with a glossiness close to 0, the content of the gloss regulator in the surface protective layer is further increased, so it is difficult to form a surface protective layer with a smooth surface without generating streaks, spots, etc. when forming the surface protective layer.

[0115] The decorative sheet 1 can obtain a low gloss decorative sheet with a glossiness of 15 or less while maintaining the same performance as a decorative sheet with a glossiness of 20 or more. Here, the "glossiness" is a value measured at an incident angle of 60 degrees using a gloss meter according to JIS Z8741.

[0116] <Hidden Layer 8>

[0117] In addition, when it is desired to provide concealment to the base material B in the decorative sheet 1, a coloring sheet may be used on the raw material layer 2 or an opaque concealing layer 8 may be provided. The concealing layer 8 may be basically made of the same material as the pattern layer 3, but since concealment is the purpose, it is preferred to use an opaque pigment, titanium oxide, iron oxide, etc. as the pigment. In addition, in order to improve concealment, metals such as gold, silver, copper, and aluminum may be added. Usually, aluminum in a thin sheet form is often added.

[0118] (Manufacturing method)

[0119] A production example of the decorative sheet 1 will be described.

[0120] A resin film is used as the raw material layer 2, and a surface protection layer 5 is formed on the raw material layer 2 by printing. For the surface protection layer 5, the surface of the coated ionizing radiation curable resin is irradiated with light with a wavelength of less than 200nm (the first irradiation light) to cure the surface of the ionizing radiation curable resin, and the wrinkles are deformed by internal stress to give shape. Then, in order to further cure the ionizing radiation curable resin after surface curing, ionizing radiation or UV light with a wavelength longer than the light with a wavelength of less than 200nm as the first irradiation light is irradiated. Thus, a decorative sheet 1 having a surface protection layer 5 is formed, and the surface protection layer 5 has a core 5A and a ridge 5B protruding from one surface (the upper surface) of the core 5A in a ridge shape.

[0121] (Other functions)

[0122] The decorative sheet 1 involved in this embodiment has a surface protection layer 5 with a concavo-convex shape formed on the surface. According to this structure, even if the surface protection layer does not contain a gloss regulator (matting additive), the gloss (glossiness) of the surface protection layer can be adjusted. The gloss regulator reduces the oleophobicity of the layer formed by the resin material, so fingerprints are easily attached. Since the surface protection layer 5 involved in this embodiment does not contain a gloss regulator, it does not absorb oil and the oleophobicity is relatively improved. Therefore, in various occasions such as on-site construction, furniture assembly, and daily life of residents, it is difficult to attach fingerprints to the decorative sheet 1 having the surface protection layer 5.

[0123] Furthermore, according to the configuration of the surface protection layer 5 having the uneven shape formed on the surface, the oil repellency of the surface protection layer 5 is improved, and it is possible to suppress the adsorption of oil stains and pollutants on the surface of the decorative sheet 1 .

[0124] Furthermore, since the surface protection layer 5 does not contain a gloss adjuster, when the surface of the decorative sheet 1 is scratched, the particles of the gloss adjuster do not fall off, and gloss changes and scratches on the surface of the decorative sheet 1 are unlikely to occur.

[0125] In the present embodiment, the surface protection layer 5 is formed by a layer, but is not limited to such a structure. For example, the surface protection layer 5 may be a multi-layer structure. That is, the surface protection layer 5 may be stacked with multiple layers of the same ionizing radiation curing resin, or stacked with multiple layers of different ionizing radiation curing resins, and a concave-convex shape may be formed on the surface. In the case of stacking multiple layers of different ionizing radiation curing resins, for example, as long as the main material of the outermost layer of the surface protection layer 5 is an ionizing radiation curing resin, the main component of the ionizing radiation curing resin is a bifunctional to tetrafunctional acrylic resin containing a repeating structure, and the repeating structure is any one of the structures of alkylene, ethylene oxide, propylene oxide and ε-caprolactone, and its excipient parameter is 0.8 or more and 3.4 or less, then there is no particular limitation on the layer located on the side of the raw material layer 2 of the surface protection layer 5 (that is, the layer located below the outermost layer of the surface protection layer 5).

[0126] [Example]

[0127] Hereinafter, examples based on the present invention will be described. It should be noted that in the following examples and comparative examples, the structural formula of the acrylic acid ester monomer used is appropriately used to specifically describe the chain length between the acryloyl groups of the monomer.

[0128] <Example 1>

[0129] An olefin film (manufactured by Riken Technos Corporation) with a thickness of 55 μm was used as the raw material layer. One surface of the raw material layer was subjected to corona treatment, and the surface was coated with the following surface protective layer coating liquid. The layer thickness of the surface protective layer coating liquid was set to 5 μm. Then, the surface of the surface protective layer coating liquid was irradiated with a cumulative light intensity of 100 mJ / cm 2 Then, the surface was irradiated with a Xe excimer lamp having a wavelength of 172 nm to shape the surface. Then, the surface protective layer coating liquid was cured by irradiation with 100 kGy of ionizing radiation to form a surface protective layer 5, thereby obtaining a decorative sheet of Example 1 having a total thickness of 60 μm.

[0130] (Surface protection layer coating liquid)

[0131] The surface protective layer coating liquid is composed of the following particles mixed with the following ionizing radiation curable resin.

[0132] ·Ionizing radiation curable resin

[0133] (Bifunctional acrylate monomer)

[0134] Product name: NK Ester A-400 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0135] Mixing: 100 parts by mass

[0136] ·particle

[0137] Product name: Sylysia 250N (manufactured by Fuji Silysia Chemical Ltd.)

[0138] Particle size: 5μm

[0139] Mixing: 0.5 parts by mass

[0140] ·Chain length between acryloyl groups

[0141] [Chemical formula 4]

[0142]

[0143] The acrylic acid ester monomer used in Example 1 can be represented by the above structural formula, and by counting the carbon and oxygen atoms of the carbonyl carbon connected to the arrow, the "inter-acryloyl chain length" is "30". In addition, the number of functional groups is "2".

[0144] <Example 2>

[0145] A decorative sheet of Example 2 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monomer in the ionizing radiation curable resin of Example 1.

[0146] ·Ionizing radiation curable resin

[0147] (Bifunctional acrylate monomer)

[0148] Product name: NK Ester A-200 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0149] Mixing: 100 parts by mass

[0150] · Chain length between acryloyl groups

[0151] [Chemical formula 5]

[0152]

[0153] The acrylic acid ester monomer used in Example 2 can be represented by the above structural formula, and by counting the carbon and oxygen atoms of the carbonyl carbon connected to the arrow, the "inter-acryloyl chain length" is "15". In addition, the number of functional groups is "2".

[0154] <Example 3>

[0155] A decorative sheet of Example 3 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monomer in the ionizing radiation curable resin of Example 1.

[0156] ·Ionizing radiation curable resin

[0157] (Bifunctional acrylate monomer)

[0158] Product name: NK Ester APG-700 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0159] Mixing: 100 parts by mass

[0160] · Chain length between acryloyl groups

[0161] [Chemical formula 6]

[0162]

[0163] The acrylic acid ester monomer used in Example 3 can be represented by the above structural formula. By counting the carbon and oxygen atoms of the carbonyl carbon connected by the arrow, the "chain length between acryloyl groups" is "39". Here, the methyl group in the middle is not the shortest path and is therefore not counted. In addition, the number of functional groups is "2".

[0164] <Example 4>

[0165] A decorative sheet of Example 4 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monomer in the ionizing radiation curable resin of Example 1.

[0166] ·Ionizing radiation curable resin

[0167] (Bifunctional acrylate monomer)

[0168] Product name: NK Ester APG-400 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0169] Mixing: 100 parts by mass

[0170] · Chain length between acryloyl groups

[0171] [Chemical formula 7]

[0172]

[0173] The acrylic acid ester monomer used in Example 4 can be represented by the above structural formula. By counting the carbon and oxygen atoms of the carbonyl carbon connected by the arrow, the "chain length between acryloyl groups" is "24". Here, the methyl group in the middle is not the shortest path and is therefore not counted. In addition, the number of functional groups is "2".

[0174] <Example 5>

[0175] A decorative sheet of Example 5 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monomer in the ionizing radiation curable resin of Example 1.

[0176] ·Ionizing radiation curable resin

[0177] (Bifunctional acrylate monomer)

[0178] Product name: Light Acrylate SR495 (manufactured by Sartomer Co., Ltd.)

[0179] Mixing: 100 parts by mass

[0180] <Example 6>

[0181] A decorative sheet of Example 6 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monomer in the ionizing radiation curable resin of Example 1.

[0182] ·Ionizing radiation curable resin

[0183] (Bifunctional acrylate monomer)

[0184] Product name: 1.6HX-A (manufactured by Kyoeisha Chemical Co., Ltd.)

[0185] Mixing: 100 parts by mass

[0186] · Chain length between acryloyl groups

[0187] [Chemical formula 8]

[0188]

[0189] The acrylic acid ester monomer used in Example 6 can be represented by the above structural formula, and by counting the carbon and oxygen atoms of the carbonyl carbon connected to the arrow, the "inter-acryloyl chain length" is "10". In addition, the number of functional groups is "2".

[0190] <Example 7>

[0191] A decorative sheet of Example 7 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monomer in the ionizing radiation curable resin of Example 1.

[0192] ·Ionizing radiation curable resin

[0193] (Bifunctional acrylate monomer)

[0194] Product name: A-DOD-N (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0195] Mixing: 100 parts by mass

[0196] <Example 8>

[0197] A decorative sheet of Example 8 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following trifunctional monomer in the ionizing radiation curable resin of Example 1.

[0198] ·Ionizing radiation curable resin

[0199] (Trifunctional acrylate monomer)

[0200] Product name: SR502 (manufactured by Sartomer Co., Ltd.)

[0201] Mixing: 100 parts by mass

[0202] · Chain length between acryloyl groups

[0203] [Chemical formula 9]

[0204]

[0205] The acrylic acid ester monomer used in Example 8 can be represented by the above structural formula, and by counting the carbon and oxygen atoms of the carbonyl carbon connected to the arrow, the "inter-acryloyl chain length" is "25". In addition, the number of functional groups is "3".

[0206] <Example 9>

[0207] A decorative sheet of Example 9 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following trifunctional monomer in the ionizing radiation curable resin of Example 1.

[0208] ·Ionizing radiation curable resin

[0209] (Trifunctional acrylate monomer)

[0210] Product name: SR9035 (manufactured by Sartomer Co., Ltd.)

[0211] Mixing: 100 parts by mass

[0212] <Example 10>

[0213] A decorative sheet of Example 10 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following tetrafunctional monomer in the ionizing radiation curable resin of Example 1.

[0214] ·Ionizing radiation curable resin

[0215] (quadrifunctional acrylate monomer)

[0216] Product name: ATM-35E (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0217] Mixing: 100 parts by mass

[0218] <Example 11>

[0219] A decorative sheet of Example 11 having a total thickness of 56 μm was obtained in the same manner as in Example 1 except that the layer thickness of the surface protection layer coating liquid of Example 1 was 1 μm.

[0220] <Example 12>

[0221] A decorative sheet of Example 12 having a total thickness of 57 μm was obtained in the same manner as in Example 1 except that the layer thickness of the surface protection layer coating liquid of Example 1 was 2 μm.

[0222] <Example 13>

[0223] A decorative sheet of Example 13 having a total thickness of 75 μm was obtained in the same manner as in Example 1 except that the layer thickness of the surface protection layer coating liquid of Example 1 was 20 μm.

[0224] <Example 14>

[0225] A decorative sheet of Example 14 having a total thickness of 80 μm was obtained in the same manner as in Example 1 except that the layer thickness of the surface protection layer coating liquid of Example 1 was 25 μm.

[0226] <Example 15>

[0227] A decorative sheet of Example 15 was obtained in the same manner as in Example 1 except that the particles of Example 1 were not blended.

[0228] <Example 16>

[0229] A decorative sheet of Example 16 was obtained in the same manner as in Example 1 except that the particles of Example 1 were replaced with the following particles.

[0230] ·particle

[0231] Product name: Sylysia 450 (manufactured by Fuji Silysia Chemical Ltd.)

[0232] Particle size: 8.0 μm

[0233] Mixing: 0.5 parts by mass

[0234] <Example 17>

[0235] A decorative sheet of Example 17 was obtained in the same manner as in Example 1 except that the particles of Example 1 were replaced with the following particles.

[0236] ·particle

[0237] Product name: Sylysia 780 (manufactured by Fuji Silysia Chemical Ltd.)

[0238] Particle size: 11.3 μm

[0239] Mixing: 0.5 parts by mass

[0240] <Example 18>

[0241] A decorative sheet of Example 18 was obtained in the same manner as in Example 1 except that the blending amount of the particles of Example 1 was changed to 10 parts by mass.

[0242] <Example 19>

[0243] A decorative sheet of Example 19 was obtained in the same manner as in Example 1 except that the blending amount of the particles of Example 1 was changed to 11 parts by mass.

[0244] <Example 20>

[0245] A decorative sheet of Example 20 was obtained in the same manner as in Example 1 except that the layer thickness of the surface protective layer coating liquid of Example 1 was 1.5 μm and the blending amount of the particles of Example 1 was 0.4 parts by mass.

[0246] <Example 21>

[0247] The decorative sheet of Example 20 was obtained in the same manner as in Example 1 except that the layer thickness of the surface protective layer coating liquid of Example 1 was 25 μm and the particles of Example 1 were not blended.

[0248] <Comparative Example 1>

[0249] A decorative sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monofunctional monomer in the ionizing radiation curable resin of Example 1.

[0250] ·Ionizing radiation curable resin

[0251] (monofunctional acrylate monomer)

[0252] Product name: MTG-A (manufactured by Kyoeisha Chemical Co., Ltd.)

[0253] Mixing: 100 parts by mass

[0254] <Comparative Example 2>

[0255] A decorative sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following monofunctional monomer in the ionizing radiation curable resin of Example 1.

[0256] ·Ionizing radiation curable resin

[0257] (monofunctional acrylate monomer)

[0258] Product name: AM-90G (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0259] Mixing: 100 parts by mass

[0260] ·Chain length between acryloyl groups

[0261] [Chemical formula 10]

[0262]

[0263] The acrylic acid ester monomer used in Comparative Example 2 can be represented by the above structural formula, and by counting the carbon and oxygen atoms of the carbonyl carbon connecting the arrow and one terminal carbon atom, the "inter-acryloyl chain length" is "29". In addition, the number of functional groups is "1".

[0264] <Comparative Example 3>

[0265] A decorative sheet of Comparative Example 3 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following bifunctional monomer in the ionizing radiation curable resin of Example 1.

[0266] ·Ionizing radiation curable resin

[0267] (Bifunctional acrylate monomer)

[0268] Product name: D5831 (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0269] Mixing: 100 parts by mass

[0270] <Comparative Example 4>

[0271] A decorative sheet of Comparative Example 4 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following bifunctional monomer in the ionizing radiation curable resin of Example 1.

[0272] ·Ionizing radiation curable resin

[0273] (Bifunctional acrylate monomer)

[0274] Product name: A-600 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0275] Mixing: 100 parts by mass

[0276] <Comparative Example 5>

[0277] A decorative sheet of Comparative Example 5 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following trifunctional monomer in the ionizing radiation curable resin of Example 1.

[0278] ·Ionizing radiation curable resin

[0279] (Trifunctional acrylate monomer)

[0280] Product name: A-TMPT (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0281] Mixing: 100 parts by mass

[0282] <Comparative Example 6>

[0283] A decorative sheet of Comparative Example 6 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following trifunctional monomer in the ionizing radiation curable resin of Example 1.

[0284] ·Ionizing radiation curable resin

[0285] (Trifunctional acrylate monomer)

[0286] Product name: SR454 (manufactured by Sartomer Co., Ltd.)

[0287] Mixing: 100 parts by mass

[0288] <Comparative Example 7>

[0289] A decorative sheet of Comparative Example 7 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following tetrafunctional monomer in the ionizing radiation curable resin of Example 1.

[0290] ·Ionizing radiation curable resin

[0291] (quadrifunctional acrylate monomer)

[0292] Product name: D5687 (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0293] Mixing: 100 parts by mass

[0294] <Comparative Example 8>

[0295] A decorative sheet of Comparative Example 8 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following tetrafunctional monomer in the ionizing radiation curable resin of Example 1.

[0296] ·Ionizing radiation curable resin

[0297] (quadrifunctional acrylate monomer)

[0298] Product name: A-TMMT (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0299] Mixing: 100 parts by mass

[0300] <Comparative Example 9>

[0301] A decorative sheet of Comparative Example 9 was obtained in the same manner as in Example 1 except that the bifunctional acrylate monomer was replaced with the following tetrafunctional monomer in the ionizing radiation curable resin of Example 1.

[0302] ·Ionizing radiation curable resin

[0303] (quadrifunctional acrylate monomer)

[0304] Product name: ATM-4E (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0305] Mixing: 100 parts by mass

[0306] <Comparative Example 10>

[0307] In the ionizing radiation curable resin of Example 1, the decorative sheet of Comparative Example 10 was obtained in the same manner as in Example 1 except that the difunctional acrylate monomer was replaced with the following hexafunctional monomer. It should be noted that, although hexafunctional is expressed here for convenience, it is actually a mixture of 5-6 functional monomers, and the number of functional groups is calculated (calculated) based on the acid value (mg KOH / g).

[0308] ·Ionizing radiation curable resin

[0309] (6-functional acrylate monomer)

[0310] Product name: A-DPH (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0311] Mixing: 100 parts by mass

[0312] ·Chain length between acryloyl groups

[0313] [Chemical formula 11]

[0314]

[0315] The acrylic acid ester monomer used in Comparative Example 10 can be represented by the above structural formula, and by counting the carbon and oxygen atoms of the carbonyl carbon connected by the arrow, the "chain length between acryloyl groups" is "11". Here, the "chain length between acryloyl groups" is the maximum value among the assumed multiple carbonyl carbons. In addition, the number of functional groups is "6".

[0316] <Comparative Example 11>

[0317] In the ionizing radiation curable resin of Example 1, a decorative sheet of Comparative Example 11 was obtained in the same manner as in Example 1 except that the difunctional acrylate monomer was replaced with the following hexafunctional monomer. It should be noted that, although hexafunctional is expressed here for convenience, it is actually a mixture of 5-6 functional monomers, and the number of functional groups is calculated (calculated) based on the acid value (mg KOH / g).

[0318] ·Ionizing radiation curable resin

[0319] (6-functional acrylate monomer)

[0320] Product name: A-DPH-12E (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0321] Mixing: 100 parts by mass

[0322] <Comparative Example 12>

[0323] A decorative sheet of Comparative Example 12 was obtained in the same manner as in Example 1 except that the excimer lamp irradiation of Example 1 was not performed and the amount of particles added was changed to 15 parts by mass.

[0324] (evaluate)

[0325] The decorative sheets of Examples 1 to 21 and Comparative Examples 1 to 12 obtained by the above method were evaluated.

[0326] In the present example, if the evaluation is "○" or "△", there is no problem in actual use, and thus it is regarded as passing.

[0327] <Surface Condition>

[0328] As for the surface state, the surface uniformity was evaluated by visual inspection.

[0329] The evaluation criteria are as follows.

[0330] 0:Uniform surface condition

[0331] △: There is unevenness in some parts

[0332] ×: Surface condition that is uneven across the entire surface

[0333] <Glossiness>

[0334] The glossiness was measured at 60° glossiness using Rhopoint IQ (manufactured by KONICA MINOLTA, INC.) In Tables 1 and 2, the 60° glossiness is indicated as “60° glossiness value”.

[0335] Note that a glossiness of 15 or less is generally regarded as low gloss, and therefore “15 or less” was regarded as acceptable in this example.

[0336] <Anti-fingerprint property: Wiping property evaluation>

[0337] As the anti-fingerprint evaluation, the fingerprint wiping property evaluation was performed.

[0338] The 60-degree glossiness of the surface of each decorative sheet was measured as the "initial glossiness". Next, after the anti-fingerprint evaluation liquid was attached to the surface protection layer, the anti-fingerprint evaluation liquid attached to the surface of the decorative sheet was wiped off. Then, the 60-degree glossiness of the portion after the anti-fingerprint evaluation liquid was wiped off was measured as the "glossiness after wiping". Here, a higher fatty acid was used as the anti-fingerprint evaluation liquid.

[0339] The fingerprint wipe rate is calculated as follows.

[0340] Fingerprint wiping rate (%) = (gloss after wiping / initial gloss) × 100

[0341] The evaluation criteria are as follows.

[0342] ○: 70% or more and less than 250%

[0343] △: 50% or more and less than 70%, or 250% or more and less than 300%

[0344] ×: less than 50%, or more than 300%

[0345] <Pollution resistance>

[0346] As an evaluation of stain resistance, according to the stain A test specified in the Japanese Agricultural Standards (JAS), lines with a width of 10 mm were drawn with blue ink, black quick-drying ink and red crayon respectively. After leaving for 4 hours, the lines of blue ink, black quick-drying ink and red crayon were wiped with ethanol in a cloth to evaluate the stain resistance to ink.

[0347] The evaluation criteria are as follows.

[0348] ○: Can easily wipe the colored threads

[0349] △: You can wipe part of each color thread, but dirt will remain on some of them.

[0350] ×: Colored threads cannot be wiped

[0351] <Scratch resistance test: Stainless steel wool friction test>

[0352] The obtained decorative sheet was attached to the wooden substrate B using a urethane adhesive, and then a stainless steel wool friction test was performed as a scratch resistance evaluation. The stainless steel wool was rubbed back and forth 20 times with a load of 100 g, and the scratches and gloss changes on the decorative sheet surface were visually confirmed.

[0353] The evaluation criteria are as follows.

[0354] 0: No surface damage or gloss change

[0355] △: Slight damage or gloss change on the surface

[0356] ×: The surface has obvious damage or gloss changes

[0357] <Bending workability test>

[0358] After the obtained decorative sheet is attached to the wooden substrate B using a carbamate adhesive with the surface on the original material layer side (i.e., the back side of the decorative sheet) facing the wooden substrate B side, a V-shaped groove is cut to the boundary where the wooden substrate B and the decorative sheet 1 are bonded without damaging the decorative sheet.

[0359] Next, the wooden substrate B was bent to 90 degrees along the V-groove so that the surface of the decorative sheet on the surface protection layer side (i.e., the surface of the decorative sheet) became a mountain fold, and an optical microscope was used to observe whether the bent portion of the decorative sheet surface was whitened or cracked, thereby evaluating the bending workability.

[0360] The evaluation criteria are as follows.

[0361] ○: No whitening or cracking was observed

[0362] △: Whitening was observed in some areas

[0363] ×: Whitening is observed on the entire surface or cracks are observed on part of the surface

[0364] The evaluation results are shown in Tables 1 and 2.

[0365] [Table 1]

[0366]

[0367] [Table 2]

[0368]

[0369]

[0370] As shown in Table 1, the decorative sheets of Examples 1 to 21 can provide low gloss (glossiness of 15 or less) and have fingerprint resistance, scratch resistance, stain resistance, and bending processability. In addition to the surface shape of the surface protective layer and the resin composition of the surface protective layer, the performance can be further improved by optimizing the layer thickness of the surface protective layer, the particle size of the particles to be matched, and the amount of addition.

[0371] In addition, for example, the present invention can adopt the following configurations. (1)

[0373] A decorative sheet comprising a raw material layer and a surface protection layer provided on one surface of the raw material layer, characterized in that:

[0374] The glossiness of the surface protection layer is below 15,

[0375] The surface protection layer has a ridge portion provided on the surface thereof so as to protrude in a ridge shape and is formed with a concavo-convex shape.

[0376] The main material of the surface protection layer is ionizing radiation curable resin.

[0377] The main component of the ionizing radiation curable resin is an acrylic resin having a repeating structure.

[0378] The repeating structure is any one of alkylene, ethylene oxide, propylene oxide and ε-caprolactone structures,

[0379] The acrylic monomer forming the acrylic resin has an acryloyl group in the range of 2 to 4 both inclusive, and a shaping parameter represented by the following Formula 1 is in the range of 0.8 to 3.4 both inclusive.

[0380] [Mathematical formula 3]

[0381]

[0382] (In Formula 1, "the number of functional groups" refers to the number of acryloyl groups (functional groups) possessed by the acrylic monomer, and "the chain length between acryloyl groups" refers to the total number of carbon atoms and oxygen atoms connecting the carbonyl carbons of the acryloyl groups possessed by the acrylic monomer. It should be noted that "the chain length between acryloyl groups" does not include the number of methyl carbons branched in the middle like propylene oxide. That is, "the chain length between acryloyl groups" refers to the number of atoms connecting the shortest acryloyl groups. In addition, when the acrylic monomer has three or more acryloyl groups, the largest value is selected from the combination of all the chain lengths between acryloyl groups, and this value (the number of atoms) is set as the "chain length between acryloyl groups" in Formula 1.) (2)

[0384] The decorative sheet according to (1) above, wherein the RSm of the concavo-convex shape of the surface protection layer is 300 or less. (3)

[0386] The decorative sheet according to (1) or (2) above is characterized in that the thickness of the surface protection layer is in the range of 2 μm to 20 μm. (4)

[0388] The decorative sheet according to any one of (1) to (3) above, wherein the surface protective layer contains particles having an average particle size of 10 μm or less in a range of 0.5 parts by mass to 10 parts by mass relative to 100 parts by mass of the ionizing radiation curable resin. (5)

[0390] A method for manufacturing a decorative sheet, characterized in that:

[0391] The surface of the applied ionizing radiation curable resin is irradiated with light having a wavelength of 200 nm or less and then irradiated with ionizing radiation or UV light having a wavelength longer than the light having a wavelength of 200 nm or less, thereby forming a surface protective layer having ridged portions protruding in a ridge shape. (6)

[0393] The method for producing a decorative sheet according to the above (5) is characterized in that the wavelength of the light having a wavelength of 200 nm or less is 172 nm.

[0394] Explanation of symbols

[0395] 1 decorative sheet

[0396] 2 Raw material layer

[0397] 3 pattern layers

[0398] 4 Transparent resin layer

[0399] 5. Surface protection layer

[0400] 6 Primer coat

[0401] 7 Adhesive layer

[0402] 8 Hidden Layer

[0403] 11Decoration Materials

[0404] B substrate

Claims

1. A decorative sheet comprising a raw material layer and a surface protection layer provided on one surface of the raw material layer, characterized in that: The glossiness of the surface protection layer is below 15, The surface protection layer has a ridge portion provided on the surface thereof so as to protrude in a ridge shape and is formed with a concavo-convex shape. The main material of the surface protection layer is ionizing radiation curable resin. The main component of the ionizing radiation curable resin is an acrylic resin having a repeating structure. The repeating structure is any one of the structures of alkylene, ethylene oxide, propylene oxide and ε-caprolactone, The acrylic monomer forming the acrylic resin has an acryloyl group in the range of 2 to 4, and the excipient parameter represented by the following formula 1 is in the range of 0.8 to 3.

4. [Mathematical formula 1] In Formula 1, "the number of functional groups" refers to the number of acryloyl groups (functional groups) possessed by the acrylic monomer, and "chain length between acryloyl groups" refers to the total number of carbon atoms and oxygen atoms between carbonyl carbons connecting acryloyl groups possessed by the acrylic monomer. It should be noted that "chain length between acryloyl groups" does not include the number of methyl carbons branched midway like propylene oxide, that is, "chain length between acryloyl groups" refers to the number of atoms between the shortest connecting acryloyl groups. In addition, in the case where the acrylic monomer has more than 3 acryloyl groups, the largest value is selected from the combination of all chain lengths between acryloyl groups, and this value (number of atoms) is set as the "chain length between acryloyl groups" in Formula 1.

2. The decorative sheet according to claim 1, characterized in that: The RSm of the concavo-convex shape of the surface protection layer is 300 or less.

3. The decorative sheet according to claim 2, characterized in that: The thickness of the surface protection layer is in the range of 2 μm to 20 μm.

4. The decorative sheet according to claim 3, characterized in that: The surface protective layer contains particles having an average particle size of 10 μm or less in a range of 0.5 parts by mass to 10 parts by mass based on 100 parts by mass of the ionizing radiation curable resin.

5. A method for manufacturing a decorative sheet, characterized in that the surface of a coated ionizing radiation curing resin is irradiated with light having a wavelength of less than 200 nm, and then irradiated with ionizing radiation or UV light having a wavelength longer than the light having a wavelength of less than 200 nm, thereby forming a surface protective layer having a ridge-shaped portion protruding in a ridge shape.

6. The method for manufacturing a decorative sheet according to claim 5, characterized in that: The wavelength of the light with a wavelength of less than 200 nm is 172 nm.

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