Decorative sheet

Abstract

To provide a decorative sheet having low glossiness due to mat effect and excellent scratch resistance.SOLUTION: A decorative sheet 1 includes a substrate 2 and a surface layer 3 provided on a surface 2a of the substrate 2 and comprising an excimer light irradiation product containing 2-10 functional urethane acrylates, monofunctional acrylates, and polyfunctional (meth)acrylates. The mass ratio of the 2-10 functional urethane acrylates and the monofunctional acrylates in the surface layer 3 satisfies 2-10 functional urethane acrylate:monofunctional acrylate=20:80-80:20, the polyfunctional (meth)acrylates include 6-functional acrylates, and a content of the 6-functional acrylates is 30 pts.mass or over and 120 pts.mass or under relative to a total of 100 pts.mass of the combined content of the 2-10 functional urethane acrylates and the monofunctional acrylates in the surface layer 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a decorative sheet. [Background technology]

[0002] Decorative sheets are used to enhance design by providing surface decoration in various applications such as wall materials, construction materials, building materials such as fittings, surface decoration of furniture, etc., automotive interiors, low-electricity electrical coverings, etc. Known decorative sheets include, for example, those having a layer with a low gloss (matte) effect provided on a substrate.

[0003] For example, a decorative sheet has been proposed in which the surface of a coating film construction provided on a substrate is irradiated with excimer light from an excimer lamp, thereby reducing the gloss of the portion of the surface of the coating film construction irradiated with the electromagnetic waves compared to before the electromagnetic waves were irradiated. It is described that such a configuration can provide a decorative sheet having areas with different matte textures (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-164901 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the decorative sheet described in the above Patent Document 1, since it is merely irradiated with excimer light, there is a problem that a sufficient matte effect cannot be obtained and low gloss is difficult to achieve.

[0006] Furthermore, in addition to the low gloss mentioned above, scratch resistance is also required for decorative sheets. However, with conventional formulations that increase hardness to improve scratch resistance, the surface is less likely to deform during the curing process, and wrinkle formation that results in low gloss is insufficient, making it difficult to achieve both low gloss and scratch resistance.

[0007] Therefore, the present invention has been made in consideration of the above problems, and has an object to provide a decorative sheet that has low gloss due to a matte effect and also has excellent scratch resistance. [Means for solving the problem]

[0008] In order to achieve the above object, the decorative sheet of the present invention comprises a substrate and a surface layer which is provided on the surface of the substrate and which is an excimer light irradiated product containing a 2-10 functional urethane acrylate, a monofunctional acrylate and a polyfunctional (meth)acrylate, the mass ratio of the 2-10 functional urethane acrylate to the monofunctional acrylate in the surface layer being 2-10 functional urethane acrylate:monofunctional acrylate=20:80 to 80:20, the polyfunctional (meth)acrylate containing a hexafunctional acrylate, and the content of the hexafunctional acrylate relative to the total 100 parts by mass of the content of the 2-10 functional urethane acrylate and the content of the monofunctional acrylate in the surface layer being 30 parts by mass or more and 120 parts by mass or less.

[0009] The term "(meth)acrylate" used herein means acrylate or methacrylate. Effect of the Invention

[0010] According to the present invention, it is possible to provide a decorative sheet that has low gloss due to a matte effect and also has excellent scratch resistance. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a decorative sheet according to an embodiment of the present invention. [Diagram 2]2 is a laser microscope photograph showing the surface state of the surface layer in the decorative sheet of Example 1. [Diagram 3] 1 is a laser microscope photograph showing the surface state of the surface layer in the decorative sheet of Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The decorative sheet of the present invention will be specifically described below. Note that the present invention is not limited to the following embodiments, and can be appropriately modified and applied within the scope of the present invention.

[0013] <Decorative sheet> As shown in FIG. 1, the decorative sheet 1 of the present invention comprises a substrate 2 and a surface layer 3 provided on a surface 2a of the substrate 2.

[0014] <Base material> The substrate 2 is made of, for example, a thermoplastic resin sheet, and as this thermoplastic resin sheet, a sheet that is usually used for the substrate in the decorative sheet 1 can be used. Specific examples include, for example, polyvinyl chloride (PVC) sheets, glycol-modified polyethylene terephthalate (PETG) sheets, amorphous crystalline polyester resin (APET) sheets, polyolefin sheets (polyethylene sheets, polypropylene sheets, etc.), acrylonitrile-butadiene-styrene resin (ABS) sheets, polycarbonate sheets, etc. The resin may be a non-regenerated resin, a recycled resin, or a biomass-derived resin, and may be appropriately mixed and used. Note that the biomass-derived resin material is a resin material that contains a compound derived from a plant as a raw material. In addition, as the amorphous crystalline polyester resin (APET) sheet used for the substrate 2, a recycled polyethylene terephthalate (RPET) sheet made from PET bottles or the like can be used.

[0015] As the thermoplastic resin sheet, a glycol-modified polyethylene terephthalate sheet is preferred from the viewpoint of ease of processing into a quadratic curved surface and excellent three-dimensional moldability. The glycol-modified polyethylene terephthalate sheet is a type of polyethylene terephthalate, and is a non-crystalline polyester that contains, as a glycol component, ethylene glycol and a diol other than ethylene glycol (1,4-cyclohexanedimethanol), whereas the glycol component of polyethylene terephthalate is ethylene glycol.

[0016] The thermoplastic resin sheet may be a stretched sheet or an unstretched sheet. The thermoplastic resin sheet may contain additives such as colorants, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, storage stabilizers, lubricants, and fillers, as necessary. The thermoplastic resin sheet is preferably colored from the viewpoint of design.

[0017] The thickness of the substrate 2 is not particularly limited, but is preferably 50 to 800 μm, and more preferably 250 to 500 μm. If the thickness of the substrate 2 is 50 μm or more, the mechanical strength and the concealing property can be sufficiently improved. If the thickness of the substrate 2 is 800 μm or less, the three-dimensional moldability is more excellent, and it is easy to ensure the flexibility and printability.

[0018] <Surface layer> The surface layer 3 is a layer formed from an active energy ray-curable resin that polymerizes when irradiated with active energy rays (ultraviolet rays or electron beams), and is a coating of an active energy ray-curable resin (paint) whose main components are urethane acrylate, monofunctional acrylate, and polyfunctional (meth)acrylate.

[0019] The surface layer 3 can be formed by applying paint onto the surface 2a of the substrate 2 and curing the paint, and the surface layer 3 is formed of a cured product of the paint. As shown in Fig. 1, wrinkles are formed on the surface 3a of the surface layer 3 (i.e., the surface opposite to the substrate 2 side).

[0020] The urethane acrylate used may have a functionality of 2 to 10, and examples thereof include phenyl glycidyl ether acrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, and dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer. Also, EBECRYL8402, KRM8452, EBECRYL210, EBECRYL220, EBECRYL4500, EBECRYL230, EBECRLY270, EBECRYL4858, EBECRYL8804, EBECRYL8807, EBECRYL9270, EBECRYL4100, EBECRYL4666, EBECRYL4513, EBECRYL8311, EBECRYL8465, EBECRYL9260, EBECRYL8606, EBECRYL8701, KRM84 Commercially available products such as 52, KRM8667, EBECRYL4265, EBECRYL4587, EBECRYL4200, EBECRYL8210, EBECRYL1290, EBECRYL5129, EBECRYL8254, EBECRYL8301R, KRM8191, KRM8200, KRM8904, U-6LPA, UV-3300B, UV-6640B, UV-6630B, UV-7510B, UA-1100H, U-200PA, and UA-160TM (all trade names) can be used. These urethane acrylates may be used alone or in combination of two or more.

[0021] The weight average molecular weight (Mw) of the di- to deca-functional urethane acrylate is preferably not more than 10000. If the weight average molecular weight is not more than 10000, the flexibility of the surface layer 3 does not become too high, and attachment to flat or curved surfaces becomes easy.

[0022] The term "weight average molecular weight" used herein refers to the polystyrene-equivalent weight average molecular weight obtained by gel permeation chromatography (GPC) measurement.

[0023] Examples of monofunctional acrylates include ethyl carbitol acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, β-(meth)acryloyloxyethyl hydrogen phthalate, β-(meth)acryloyloxyethyl hydrogen succinate, nonylphenoxyethyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxypolyethylene glycol. (meth)acrylate, butoxy polyethylene glycol (meth)acrylate, alkyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate Acid, 3-acryloyloxyglycerin mono(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 2-hydroxy-1-(meth)acryloxy-3-(meth)acryloxypropane, polypropylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, poly-ε-caprolactone mono(meth)acrylate, dialkylaminoethyl(meth)acrylate, glycidyl(meth)acrylate, mono[2-(meth)acryloyloxyethyl]acid phosphe acrylate, trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 2,2,3,4,4,4-hexafluorobutyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, dicyclopentenyloxyalkyl (meth)acrylate, dicyclopentenyl (meth)acrylate, tricyclodecanyl (meth)acrylate, tricyclodecanyloxyethyl (meth)acrylate, and isobornyloxyethyl (meth)acrylate. These monofunctional acrylates may be used alone or in combination of two or more.

[0024] In addition, in the decorative sheet 1 of the present invention, the blending ratio of the di- to decafunctional urethane acrylate and the monofunctional acrylate in the surface layer 3 is in the range of di- to decafunctional urethane acrylate:monofunctional acrylate=20:80 to 80:20 by mass. This is because, since the fluidity of the urethane acrylate is low, when the mass ratio of the urethane acrylate increases, wrinkles are less likely to occur on the surface 3a of the surface layer 3, and low gloss due to the matte effect is less likely to be achieved. In addition, since the reactivity of the monofunctional acrylate is low, when the mass ratio of the monofunctional acrylate increases, hardening of the coating material is less likely to occur.

[0025] Examples of polyfunctional (meth)acrylates include dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxybisphenol A diacrylate, and glycerin triacrylate. Other examples include EBECRYL140, EBECRYL145, EBECRYL150, IRR214K, EBECRYL130, EBECRYL160S, OTA480, PETIA, PETRA, EBECRYL40, PETA, EBECRYL140, EBECRL1140, EBECRYL1142, EBECRYL895, EBECRYL896, DPHA, KAYARAD DPCA-30, ADPH-12E, KAYARAD DPCA-120, TMPTA (all trade names), etc. These polyfunctional (meth)acrylates may be used alone or in combination of two or more.

[0026] Moreover, the term "polyfunctional (meth)acrylate" used herein refers to a (meth)acrylic acid ester monomer containing two or more (meth)acryloyl groups.

[0027] Here, the inventors have investigated the conditions under which low gloss and scratch resistance can be achieved simultaneously in the decorative sheet 1, and have found that by using the above-mentioned multifunctional (meth)acrylate containing a hexafunctional acrylate, it is possible to achieve both low gloss and scratch resistance in the surface layer 3.

[0028] In other words, by using a polyfunctional (meth)acrylate containing a hexafunctional acrylate, the crosslinking density of the resin is improved, and the hardness of the coating film is improved, making the coating film stronger, and as a result, it is possible to improve the scratch resistance of the surface layer 3.

[0029] Furthermore, by setting the content of the hexafunctional acrylate to 30 parts by mass or more and 120 parts by mass or less relative to 100 parts by mass of the total of the content of the di- to decafunctional urethane acrylate and the content of the monofunctional acrylate in the surface layer, it becomes possible to improve the scratch resistance while maintaining the low gloss of the surface layer 3, thereby making it possible to achieve both low gloss and scratch resistance in the surface layer 3.

[0030] If the content of the hexafunctional acrylate is less than 30 parts by mass, the scratch resistance may decrease, and if the content of the hexafunctional acrylate is more than 120 parts by mass, the scratch resistance improves, but the surface of the coating film is difficult to deform during the curing process, and wrinkle formation that brings about low gloss becomes insufficient, so the low gloss due to the matte effect may be poor. Also, if the content of the hexafunctional acrylate is 150 parts by mass or more, the low gloss due to the matte effect is significantly reduced.

[0031] Furthermore, in the decorative sheet 1 of the present invention, it is preferable that the polyfunctional (meth)acrylate contains a hexafunctional acrylate having an acrylic equivalent of no more than 160. By containing a hexafunctional acrylate having an acrylic equivalent of no more than 160, the crosslink density of the resin is further improved and the hardness of the coating film can be further improved, so that the scratch resistance of the surface layer 3 can be further improved.

[0032] The term "acrylic equivalent" used herein refers to the value obtained by dividing the molecular weight of a hexafunctional acrylate by the number of functional groups in the acrylic group (that is, 6), and is expressed as the molecular weight per acrylic group.

[0033] In the decorative sheet 1 of the present invention, the content of the hexafunctional acrylate in the polyfunctional (meth)acrylate (i.e., relative to 100% by mass of the polyfunctional (meth)acrylate) is preferably 65% ​​by mass or more and 100% by mass or less. If the content of the hexafunctional acrylate is 65% by mass or more and 100% by mass or less, the content of the hexafunctional acrylate is sufficient, and the scratch resistance of the surface layer 3 can be reliably improved.

[0034] The thickness of the surface layer 3 is not particularly limited, but is preferably 1 to 10 μm. If the thickness of the surface layer 3 is 10 μm or more, the surface roughness of the surface 3a of the surface layer 3 increases, improving fingerprint resistance but decreasing tactile sensation. From the viewpoint of improving scratch resistance, the thickness of the surface layer 3 is more preferably 3 to 8 μm.

[0035] Furthermore, the coating material may contain other components in addition to the above-mentioned urethane acrylate, monofunctional acrylate, and polyfunctional (meth)acrylate, so long as the effects of the invention are not impaired. Examples of other components include vinyl chloride-vinyl acetate copolymers, photopolymerization initiators, colorants, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, storage stabilizers, plasticizers, lubricants, and fillers.

[0036] As the photopolymerization initiator, for example, an alkylphenone-based, an acylphosphine oxide-based, or a cationic initiator can be used.

[0037] <Manufacturing method> When producing the decorative sheet 1 of the present invention, first, for example, a substrate 2 made of the above-mentioned thermoplastic resin sheet is prepared. This thermoplastic resin sheet may be a commercially available one, or may be one produced by a known production method such as a calendar method or an extrusion molding method.

[0038] Next, a coating material containing, for example, urethane acrylate, monofunctional acrylate, polyfunctional (meth)acrylate, and a photopolymerization initiator added to a solvent such as methyl ethyl ketone is applied onto the surface 2a of the substrate 2, to form a coating film that will become the surface layer 3 on the surface 2a of the substrate 2.

[0039] When a urethane acrylate containing a monofunctional acrylate is used, the use of a separate monofunctional acrylate can be omitted.

[0040] The coating method is not particularly limited, and examples thereof include cast coating, die coating, gravure coating, roll knife coating, reverse roll coating, roll coating, and comma coating.

[0041] Next, excimer light is irradiated onto the coating film formed on the surface 2a of the substrate 2. More specifically, excimer light having a short peak wavelength (within a range of 120 to 230 nm) is irradiated onto the coating film.

[0042] When excimer light is irradiated using an excimer lamp, the peak wavelength of the electromagnetic wave can be changed by changing the discharge gas filled in the excimer lamp. The discharge gas for irradiating excimer light with the above peak wavelength can be, for example, Ar. 2 , Kr 2 , Xe 2 etc. can be used.

[0043] Then, by irradiating the coating with ultraviolet light (350 to 450 nm) to cure the coating, a surface layer 3 is formed on the surface of the substrate 2, as shown in Figure 1, and a decorative sheet 1 is produced in which wrinkles are formed on the surface 3a of the surface layer 3.

[0044] Even if the coating film is irradiated with excimer light having a short peak wavelength (within the range of 120 to 230 nm) instead of the ultraviolet light (350 to 450 nm), the coating film does not cure completely.

[0045] By irradiating the coating film with the above-mentioned excimer light, hardening occurs only on the outermost surface of the coating film, resulting in unevenness between the surface and the interior of the coating film, and coating components migrate from the unreacted parts inside the coating film to the surface, resulting in wrinkles being formed on the surface of the coating film.As a result, it becomes possible to control the gloss level of the surface layer 3.

[0046] Furthermore, in the decorative sheet 1 of the present invention, the gloss level of the surface 3a of the surface layer 3 is 5 or less due to the matting effect caused by the wrinkles described above, making it possible to achieve low gloss.

[0047] From the viewpoint of improving low gloss, the gloss of the surface 3a of the surface layer 3 is preferably 2 or less, more preferably 1.8 or less, and even more preferably 1.5 or less.

[0048] Additionally, the term "glossiness" as used herein is an index of low glossiness, and refers to the 60° glossiness measured in accordance with a method conforming to JIS Z 8741:1997, which refers to the glossiness calculated based on the results of measurement using a photodetector installed in the direction of the reflection angle when light is incident at an incident angle of 60° on the measurement surface (surface 3a of the surface layer 3) of the decorative sheet 1.

[0049] Furthermore, in the decorative sheet 1 of the present invention, since the multifunctional (meth)acrylate contains a hexafunctional acrylate, the scratch resistance of the surface layer 3 can be improved.

[0050] As described above, the present invention makes it possible to provide a decorative sheet that has low gloss due to a matte effect and also has excellent scratch resistance.

[0051] The above embodiment may be modified as follows.

[0052] In the above embodiment, the configuration includes the substrate 2 and the surface layer 3 provided on the surface 2a of the substrate 2, but the configuration may include a functional layer for imparting various functions as long as the effects of the present invention are not impaired. Examples of the functional layer include a matte coating layer for improving the matte effect and a printed layer for imparting design properties.

[0053] For example, a matte coating layer may be provided between the substrate 2 and the surface layer 3, and the decorative sheet may have a three-layer structure including the substrate 2, the matte coating layer provided on the surface 2a of the substrate 2, and the surface layer 3 provided on the surface of the matte coating layer, with the substrate / matte coating layer / surface layer laminated in this order. With this configuration, the matte effect of the decorative sheet 1 can be improved.

[0054] Examples of materials that can be used to form the matte coating layer include acrylic resins having silica particles, vinyl chloride resins, vinyl chloride-vinyl acetate copolymers, chlorinated polypropylene resins, polyester resins, urethane resins, fluorine resins, and polyolefin resins.

[0055] Alternatively, a printed layer may be provided between the base material 2 and the surface layer 3, to form a decorative sheet having a three-layer structure including the base material 2, the printed layer provided on the surface 2a of the base material 2, and the surface layer 3 provided on the surface of the printed layer, laminated in the order of base material / printed layer / surface layer. With this configuration, it is possible to provide the matte effect of the decorative sheet 1 while also imparting designability.

[0056] Alternatively, a printed layer and a transparent resin layer may be provided between the substrate 2 and the surface layer 3, to provide a decorative sheet having a four-layer structure including the substrate 2, a printed layer provided on the surface 2a of the substrate 2, a transparent resin layer provided on the surface of the printed layer, and a surface layer 3 provided on the surface of the transparent resin layer, laminated in the order of substrate / printed layer / transparent resin layer / surface layer. This configuration provides the matte effect of the decorative sheet 1 while also providing designability.

[0057] Alternatively, a printed layer and a matte coating layer may be provided between the substrate 2 and the surface layer 3, to provide a decorative sheet having a four-layer structure including the substrate 2, a printed layer provided on the surface 2a of the substrate 2, a matte coating layer provided on the surface of the printed layer, and a surface layer 3 provided on the surface of the matte coating layer, laminated in the order of substrate / printed layer / matte coating layer / surface layer. With this configuration, the matte effect of the decorative sheet 1 can be improved, and designability can be imparted.

[0058] The print layer can be formed from a material such as a binder resin and a colorant.

[0059] Examples of the binder resin include acrylic resins, vinyl chloride-vinyl acetate copolymers, chlorinated polypropylene resins, polyester resins, cellulose resins, and urethane resins.

[0060] Examples of colorants include inorganic pigments such as titanium white, zinc white, carbon black, iron black, red oxide, chrome vermilion, cadmium red, ultramarine, cobalt blue, yellow lead, and titanium yellow, organic pigments such as phthalocyanine blue, indanthrene blue, isoindolinone yellow, benzilidine yellow, quinacridone red, polyazo red, perylene red, and aniline black, and pearlescent (pearl) pigments such as scaly foil powder of aluminum, brass, etc. These colorants can be used alone or in combination of two or more.

[0061] In addition, the printing layer may contain, if necessary, ultraviolet absorbents, light stabilizers, antioxidants, antistatic agents, storage stabilizers, plasticizers, lubricants, fillers, etc.

[0062] In addition, in the above-mentioned four-layer structure, a transparent resin layer may be provided between the printed layer and the matte coating layer, resulting in a decorative sheet having a five-layer structure laminated in the order of substrate / printed layer / transparent resin layer / matte coating layer / surface layer.

[0063] Examples of materials that can be used to form the transparent resin layer include acrylic resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymers, chlorinated polypropylene resins, polyester resins, urethane resins, fluorine resins, and polyolefin resins.

[0064] In addition, a primer layer may be provided between each of the above-mentioned substrate, functional layer, transparent resin layer, and surface layer in order to improve the adhesion between the layers. The primer for forming the primer layer is not particularly limited, and for example, an acrylic resin, a vinyl chloride-vinyl acetate copolymer, a chlorinated polypropylene resin, a polyester resin, a urethane resin, etc. can be used. EXAMPLES

[0065] The present invention will be described below based on examples. Note that the present invention is not limited to these examples, and these examples can be modified or changed based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0066] The materials used in producing the decorative sheet are shown below. (1) Urethane acrylate-1: Bifunctional urethane acrylate (weight average molecular weight: 13,000, manufactured by Mitsubishi Chemical Corporation, product name: UV-3300B) (2) Urethane acrylate-2: Bifunctional urethane acrylate (weight average molecular weight: 5000, manufactured by Mitsubishi Chemical Corporation, product name: UV-6640B) (3) Urethane acrylate-3: Bifunctional urethane acrylate (weight average molecular weight: 3000, manufactured by Mitsubishi Chemical Corporation, product name: UV-6630B) (4) Urethane acrylate-4: Bifunctional urethane acrylate (weight average molecular weight: 1100, manufactured by Daicel Allnex Co., Ltd., product name: KRM8191) (5) Monofunctional acrylate-1: Tetrahydrofurfuryl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., product name: Tetrahydrofurfuryl Acrylate) (6) Multifunctional (meth)acrylate-1: 6-functional acrylate (acrylic equivalent: 87, molecular weight: 520, manufactured by Daicel Allnex Co., Ltd., trade name: dipentaerythritol hexaacrylate (DPHA)) (7) Multifunctional (meth)acrylate-2:6-functional acrylate (acrylic equivalent: 153, molecular weight: 920, manufactured by Nippon Kayaku Co., Ltd., trade name: caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-30)) (8) Multifunctional (meth)acrylate-3:6-functional acrylate (acrylic equivalent: 184, molecular weight: 1106, manufactured by Shin-Nakamura Chemical Co., Ltd., product name: ethoxylated dipentaerythritol hexaacrylate (ADPH-12E)) (9) Multifunctional (meth)acrylate-4:6-functional acrylate (acrylic equivalent: 292, molecular weight: 1754, manufactured by Nippon Kayaku Co., Ltd., trade name: caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120)) (10) Multifunctional (meth)acrylate-5: 4-functional acrylate (acrylic equivalent: 117, molecular weight: 466, manufactured by Daicel-Allnex Corporation, trade name: ditrimethylolpropane tetraacrylate (EBECRYL140)) (11) Multifunctional (meth)acrylate-6: Trifunctional acrylate (acrylic equivalent: 95, molecular weight: 286, manufactured by Daicel Allnex, trade name: trimethylolpropane triacrylate (TMPTA)) (12) Initiator: alkylphenone-based photopolymerization initiator (manufactured by IGM Resins BV, product name: Omnirad1173)

[0067] Example 1 <Preparation of decorative sheet> First, a polyester resin film having a thickness of 200 μm was prepared as a substrate. Next, the materials shown in Table 1 were mixed to prepare a coating material of Example 1 having the composition (parts by mass) shown in Table 1. This coating material was applied onto the surface of the substrate using a bar coater to form a coating film that would become a surface layer on the surface of the substrate.

[0068] Next, the above coating film was dried using a hot air dryer at a temperature of 50° C. for 20 seconds.

[0069] Next, using an excimer irradiation device (manufactured by Ushio Inc., product name: 172 nm Light Emission Unit, model: SUS1000), Xe 2 The coating was irradiated with excimer light (peak wavelength: 172 nm) using as the discharge gas. The cumulative light amount was 11 mJ / cm 2 , the irradiation intensity is 25mW / cm 2 The irradiation was performed so that

[0070] Then, the coating film was irradiated with ultraviolet light (dominant wavelength: 365 nm) using an ultraviolet light irradiation device (4 kW ultraviolet curing high pressure mercury lamp (ECS-401GX) manufactured by Eye Graphics Co., Ltd.) to photo-cure the coating film, thereby forming a surface layer on the surface of the substrate and producing a decorative sheet. Note that the ultraviolet light irradiation distance was 15 cm, and the lamp movement speed was 7.8 m / min, and the ultraviolet light irradiation (illuminance: 170 mW / cm 2 ) and the irradiation dose (accumulated light amount) was set to 200 mJ / cm 2 It was decided.

[0071] Table 1 also shows the acrylic equivalent of the polyfunctional (meth)acrylate in this example and the average value of the acrylic equivalent of the polyfunctional (meth)acrylate in each formulation.

[0072] In this embodiment, the acrylic equivalent of the multifunctional (meth)acrylate is calculated by acrylic equivalent = molecular weight / number of functional groups. For example, the acrylic equivalent of multifunctional (meth)acrylate-1 is 520 / 6 = 87. The average of the multifunctional (meth)acrylic equivalents is 34 parts by mass of multifunctional (meth)acrylate-1 (acrylic equivalent: 87) and 17 parts by mass of multifunctional (meth)acrylate-3 (acrylic equivalent: 184), so the acrylic equivalent of the multifunctional (meth)acrylate is [(87 × 34) + (184 × 17)] / (34 + 17) = 119.

[0073] A laser microscope photograph showing the surface condition of the surface layer is shown in Figure 2. As shown in Figure 2, it can be seen that a large number of wrinkles are formed on the surface of the surface layer in the decorative sheet of this example.

[0074] <Thickness measurement> Next, the thickness of the surface layer (coating film) of the prepared decorative sheet was measured using a digital microscope (Keyence Corporation, product name: VHX-5000) or a field emission scanning electron microscope (SEM) (Hitachi High-Technologies Corporation, product name: S-4800).

[0075] More specifically, the sheet was cut to expose the cross section, and the cross section was observed with a digital microscope (measurement magnification: 500x) or a field emission scanning electron microscope (measurement magnification: 1000x). Five locations with high and low coating film heights were selected, the thickness was measured, and the average value was calculated. The above measurement was performed three times, and the average value of the three coating film heights was calculated to be the thickness of the surface layer. The results are shown in Table 1.

[0076] <Gloss measurement> Next, the 60° gloss of the surface of the surface layer of the prepared decorative sheet was measured using a gloss meter (manufactured by Horiba Ltd., product name: Gloss Checker IG-320) in accordance with JIS Z 8741:1997. The above measurement was performed three times, and the average value of the three gloss values ​​was calculated to be the surface gloss of the surface layer. The results are shown in Table 1.

[0077] <Evaluation of abrasion resistance (scratch resistance)> Next, the prepared decorative sheet was attached to an aluminum plate to prepare a sample, and a scratch tester (manufactured by TABER INDUSTRIES, product name: Model 502) was used to perform a scratch test under the conditions of a scratch speed of 1 mm / sec and a scratch distance of 5 mm, with a diamond needle (needle tip radius: 3 mil) of the scratch tester at an angle of 90° to the surface layer of the decorative sheet and a predetermined load being applied. The load was set to 1.5 g to 36.5 g in 3.5 g increments. The state of the surface layer of the decorative sheet after the scratch test was observed with a microscope (manufactured by Keyence, product name: VHX-8000, measurement magnification: 100 times), and the load value at which scratches were confirmed on the surface layer of the decorative sheet (the minimum load value at which scratches occurred) was recorded, and the scratch resistance was evaluated based on the following evaluation criteria. The above results are shown in Table 1.

[0078] The load at which scratches begin to appear on the surface layer of the decorative sheet is 8.5g or more: ◯ The load at which scratches begin to appear on the surface layer of the decorative sheet is less than 8.5 g: ×

[0079] (Examples 2 to 16, Comparative Examples 1 to 3) A decorative sheet was produced in the same manner as in Example 1 above, except that the compositions of the coating components were changed to the compositions (parts by mass) shown in Tables 1 to 3.

[0080] Then, the acrylic equivalent of the polyfunctional (meth)acrylate was calculated, the thickness was measured, the glossiness was measured, and the abrasion resistance (scratch resistance) was evaluated in the same manner as in Example 1. The results are shown in Tables 1 to 3.

[0081] Moreover, Fig. 3 shows a laser microscope photograph showing the surface state of the surface layer of the decorative sheet of Comparative Example 2. As shown in Fig. 3, it is clear that the decorative sheet of Comparative Example 2 does not achieve a sufficient matte effect, and uneven irregularities are formed, resulting in a decrease in aesthetic appearance (design).

[0082] [Table 1]

[0083] [Table 2]

[0084] [Table 3]

[0085] As shown in Table 1, in the decorative sheets of Examples 1 to 16 in which the mass ratio of the 2-10 functional urethane acrylate to the monofunctional acrylate in the surface layer is 20:80 to 80:20, the polyfunctional (meth)acrylate contains a hexafunctional acrylate, and the content of the hexafunctional acrylate is 30 parts by mass or more and 120 parts by mass or less per 100 parts by mass of the total of the 2-10 functional urethane acrylate content and the monofunctional acrylate content in the surface layer, it is found that the scratch resistance can be improved while maintaining low gloss in the surface layer, and a decorative sheet with excellent low gloss and scratch resistance can be obtained. [Industrial Applicability]

[0086] As described above, the present invention is suitable for decorative sheets. [Explanation of symbols]

[0087] 1 Decorative sheet 2 Base material 2a Surface of the substrate 3 Surface layer 3a Surface of the surface layer

Claims

1. A substrate; a surface layer provided on the surface of the substrate and containing a difunctional to decafunctional urethane acrylate, a monofunctional acrylate, and a polyfunctional (meth)acrylate, the surface layer being an excimer light irradiated material; Equipped with a mass ratio of the di- to deca-functional urethane acrylate to the monofunctional acrylate in the surface layer is di- to deca-functional urethane acrylate:monofunctional acrylate=20:80 to 80:20; The polyfunctional (meth)acrylate contains a hexafunctional acrylate, A decorative sheet characterized in that the content of the hexafunctional acrylate in the surface layer is 30 parts by mass or more and 120 parts by mass or less relative to 100 parts by mass of the total content of the di- to deca-functional urethane acrylate and the monofunctional acrylate.

2. 2. The decorative sheet according to claim 1, wherein the polyfunctional (meth)acrylate contains the hexafunctional acrylate having an acrylic equivalent of 160 or less.

3. 3. The decorative sheet according to claim 1, wherein the content of the hexafunctional acrylate in the polyfunctional (meth)acrylate is 65% by mass or more and 100% by mass or less.

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