JP2018171756A - Decorative sheet and decorative resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decorative sheet which has excellent scratch resistance, effectively suppresses cracks of a surface protective layer by molding under high temperature environment, and has excellent three-dimensional moldability.SOLUTION: A decorative sheet has at least a base material sheet and a surface protective layer provided on the base material sheet, where the surface protective layer is formed from a cured product of an ionizing radiation-curable resin composition containing at least polycarbonate (meth)acrylate and inorganic particles having a primary particle size of 0.25 μm or less, where an index value of a content of the inorganic particles in the surface protective layer calculated by the following expression is 2.5×10or more and 25×10or less. Expression: index value of content of inorganic particle=primary particle size (μm) of inorganic particle×(mass (g) of inorganic particle)/mass (g) of ionizing radiation-curable resin contained in surface protective layer÷thickness (μm) of surface protective layer.SELECTED DRAWING: None

Description

  The present invention relates to a decorative sheet and a decorative resin molded product.

  Decorated resin molded products decorated by laminating decorative sheets on the surface of molded products are used in various applications such as vehicle interior parts. As a molding method of such a decorative resin molded product, the decorative sheet is formed into a three-dimensional shape in advance by a vacuum mold, the molded sheet is inserted into an injection mold, and the resin in a fluid state is placed in the mold. An insert molding method (for example, see Patent Document 1) for injecting a resin and a molded sheet and a decorative sheet inserted into a mold at the time of injection molding, and a molten resin injected and injected into a cavity There is an injection molding simultaneous decorating method (for example, see Patent Document 2 and Patent Document 3) that integrates and decorates the surface of the resin molded body.

  The decorative resin molded product is provided with a surface protective layer for the purpose of improving the scratch resistance of the surface. By using an ionizing radiation curable resin such as an ultraviolet curable resin as the surface protective layer and increasing the crosslinking density of the resin that forms the surface protective layer of the decorative sheet, the surface wear resistance and scratch resistance of the decorative resin molded product are increased. Attempts have been made to improve adherence. However, in the molding method of the decorative resin molded product described above, in the insert molding method, the decorative sheet is preliminarily formed into a three-dimensional (three-dimensional) shape by a vacuum mold, and in the simultaneous injection molding method, the decorative sheet is preliminarily used. During molding or injection of molten resin, in the process of drawing and adhering along the inner peripheral surface of the cavity, the decorative sheet is molded by vacuum / pneumatic action or by pulling of molten resin pressure or shear stress Since it is extended beyond the minimum necessary amount to conform to the shape, there is a problem that a crack is formed in the surface protective layer of the curved surface portion of the molded product.

  In addition, an attempt has been made to use an ionizing radiation curable resin such as an ultraviolet curable resin as a surface protective layer, to make a semi-cured state in the decorative sheet stage, and to completely cure after the decorative molding (Patent Document 4). The surface protective layer containing the uncured resin component is easily damaged and difficult to handle, and there is a problem of mold contamination due to the uncured resin component adhering to the mold. In order to solve this problem, there is a method of providing a protective film on the semi-cured surface protective layer. However, the manufacturing is complicated and the cost is increased.

JP 2004-322501 A Japanese Patent Publication No. 50-19132 Japanese Examined Patent Publication No. 61-17255 Japanese Patent Application Laid-Open No. 6-134859

  Under such circumstances, the present invention has an excellent scratch resistance, and further, a decorative sheet having excellent three-dimensional formability, in which cracks in the surface protective layer due to molding in a high temperature environment are effectively suppressed. The main purpose is to provide Furthermore, another object of the present invention is to provide a decorative resin molded product using the decorative sheet.

The present inventor has intensively studied to solve the above problems. As a result, the decorative sheet includes at least a base sheet and a surface protective layer provided on the base sheet, and the surface protective layer has at least a polycarbonate (meth) acrylate and a primary particle size of 0.1. The index value of the content of inorganic particles in the surface protective layer, which is made of a cured product of an ionizing radiation curable resin composition containing inorganic particles of 25 μm or less and calculated by the following formula, is 2.5 × 10. ^-4 or more and 25 × 10 ⁻⁴ or less decorative sheet has excellent scratch resistance, and further, cracks in the surface protective layer due to molding in a high temperature environment are effectively suppressed and excellent It has been found that it has three-dimensional formability.

  Index value of content of inorganic particles = primary particle diameter of the inorganic particles (μm) × (mass of the inorganic particles (g) / mass of ionizing radiation curable resin contained in the surface protective layer (g)) ÷ the above Surface protective layer thickness (μm)

  The present invention has been completed by further studies based on these findings.

That is, this invention provides the invention of the aspect hung up below.
Item 1. At least a decorative sheet comprising a base sheet and a surface protective layer provided on the base sheet,
The surface protective layer comprises a cured product of an ionizing radiation curable resin composition containing at least polycarbonate (meth) acrylate and inorganic particles having a primary particle diameter of 0.25 μm or less,
Is calculated by the following equation, the index value of the content of the inorganic particles in the surface protective layer is, 2.5 × 10 ^-4 or more and 25 × 10 ^-4 or less, the decorative sheet.
Index value of content of inorganic particles = primary particle diameter of the inorganic particles (μm) × (mass of the inorganic particles (g) / mass of ionizing radiation curable resin contained in the surface protective layer (g)) ÷ the above Surface protective layer thickness (μm)
Item 2. Item 2. The decorative sheet according to Item 1, wherein a mass ratio of the polycarbonate (meth) acrylate resin and the inorganic particles contained in the ionizing radiation curable resin composition is 100: 5 to 100: 50.
Item 3. Item 3. The decorative sheet according to Item 1 or 2, wherein the inorganic particles are silica particles.
Item 4. At least a decorative resin molded product comprising a molded resin and a surface protective layer provided on the molded resin,
The surface protective layer comprises a cured product of an ionizing radiation curable resin composition containing at least polycarbonate (meth) acrylate and inorganic particles having a primary particle diameter of 0.25 μm or less,
The decorative resin molded product, wherein the index value of the content of the inorganic particles in the surface protective layer, calculated by the following formula, is 2.5 × 10 ⁻⁴ or more and 25 × 10 ⁻⁴ or less.
Index value of content of inorganic particles = primary particle diameter of the inorganic particles (μm) × (mass of the inorganic particles (g) / mass of ionizing radiation curable resin contained in the surface protective layer (g)) ÷ the above Surface protective layer thickness (μm)

  According to the present invention, it is possible to provide a decorative sheet that has excellent scratch resistance, and further effectively suppresses cracks in the surface protective layer due to molding in a high-temperature environment and has excellent three-dimensional formability. Can do. Furthermore, according to the present invention, a decorative resin molded product using the decorative sheet can also be provided.

It is a schematic sectional drawing of an example of the decorating sheet of this invention. It is a schematic sectional drawing of an example of the decorating sheet of this invention. It is a schematic sectional drawing of an example of the decorating resin molded product of this invention.

1. The decorative sheet of the present invention is a decorative sheet comprising at least a base material sheet and a surface protective layer provided on the base material sheet, and the surface protective layer is at least a polycarbonate (meta). Containing the inorganic particles in the surface protective layer, which is composed of a cured product of an ionizing radiation curable resin composition containing acrylate and inorganic particles having a primary particle size of 0.25 μm or less, and calculated by the following formula The quantity index value is 2.5 × 10 ⁻⁴ or more and 25 × 10 ⁻⁴ or less.

(Index value of the content of the inorganic particles in the surface protective layer)
Index value of content of inorganic particles = primary particle diameter of the inorganic particles (μm) × (mass of the inorganic particles (g) / mass of ionizing radiation curable resin contained in the surface protective layer (g)) ÷ the above Surface protective layer thickness (μm)

  In the decorative sheet of the present invention, the surface protective layer contains at least polycarbonate (meth) acrylate and inorganic particles having a primary particle diameter of 0.25 μm or less, and has the predetermined inorganic particle index value. Therefore, it has excellent scratch resistance, and further, cracks in the surface protective layer due to molding in a high temperature environment are effectively suppressed, and excellent three-dimensional moldability can be exhibited. Hereinafter, the decorative sheet of the present invention will be described in detail.

  In the present specification, the numerical range indicated by “to” means “above” or “below”. For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less. Further, in this specification, “(meth) acrylate” means “acrylate or methacrylate”, and other similar things have the same meaning. Further, the decorative sheet of the present invention may not have a pattern layer or the like, and may be transparent, for example.

Laminated structure of decorative sheet The decorative sheet of the present invention has at least a laminated structure in which a base sheet 1 and a surface protective layer 2 are laminated. In the decorative sheet of the present invention, a primer layer 3 is provided on the surface of the surface protective layer 2 on the substrate sheet 1 side in order to improve adhesion between the surface protective layer 2 and the layer in contact with the surface protective layer 2. May be. Moreover, you may provide the pattern layer 4 as needed in the decorating sheet of this invention for the purpose of providing a decorative property to a resin molded product. Furthermore, if the pattern layer 4 is provided between the base sheet 1 and the surface protective layer 2 for the purpose of suppressing color change or variation of the base sheet 1, the back surface (molding) of the pattern layer 4 is provided. If necessary, a concealing layer (not shown) may be provided on the resin layer 5 side). Furthermore, you may provide a back surface adhesive layer (not shown) etc. in the outermost surface by the side of the molding resin layer 5. FIG.

  As a laminated structure of the decorative sheet of the present invention, a laminated structure in which a base sheet / surface protective layer is laminated in this order; a laminated structure in which a base sheet / primer layer / surface protective layer is laminated in this order; Laminated structure in which picture layer / primer layer / surface protective layer are laminated in this order; Laminated structure in which base sheet / hiding layer / picture layer / primer layer / surface protective layer are laminated in this order; Back surface adhesive layer / base sheet Examples include a laminated structure in which / hiding layer / pattern layer / primer layer / surface protective layer are laminated in this order. In FIG. 1, the schematic sectional drawing of an example of the decorating sheet | seat on which the base material sheet / surface protective layer was laminated | stacked in this order is shown as one aspect | mode of the laminated structure of the decorating sheet of this invention. In FIG. 2, the schematic sectional drawing of an example of the decorating sheet | seat in which the base material sheet / picture layer / primer layer / surface protective layer was laminated | stacked in this order as one aspect | mode of the laminated structure of the decorating sheet of this invention is shown.

Composition of each layer forming the decorative sheet [base sheet 1]
The base sheet 1 is a layer that plays a role as a support in the decorative sheet of the present invention. It does not specifically limit as the base material sheet 1, Although a fiber sheet, a resin sheet, a metal sheet, a wood-type base material sheet etc. can be used according to the use of a decorating sheet, it is used for manufacture of a decorating resin molded product. In some cases, such as when three-dimensional formability is required, it is preferably formed of a resin sheet (resin film). The resin component used for the base sheet 1 is not particularly limited and may be appropriately selected according to the three-dimensional moldability, compatibility with the molded resin layer, and the like, and preferably a thermoplastic resin. Specific examples of the thermoplastic resin include acrylonitrile-butadiene-styrene resin (hereinafter sometimes referred to as “ABS resin”); acrylonitrile-styrene-acrylic ester resin; acrylic resin; polyolefins such as polypropylene and polyethylene Resin; polycarbonate resin; vinyl chloride resin; polyethylene terephthalate (PET). Among these, acrylic resin or ABS resin is preferable from the viewpoint of three-dimensional moldability. As a resin component which forms the base material sheet 1, only 1 type may be used and 2 or more types may be mixed and used. Moreover, the base material sheet 1 may be formed with these single layer sheets, and may be formed with the multilayer sheet | seat by the same kind or different kind | species sheet | seat.

  The base sheet 1 may be subjected to physical or chemical surface treatment such as an oxidation method or an unevenness method on one side or both sides as necessary in order to improve the adhesion with an adjacent layer. . Examples of the oxidation method performed as the surface treatment of the base sheet 1 include a corona discharge treatment, a plasma treatment, a chromium oxidation treatment, a flame treatment, a hot air treatment, and an ozone ultraviolet treatment method. Moreover, as the uneven | corrugated method performed as surface treatment of the base material sheet 1, a sandblasting method, a solvent processing method, etc. are mentioned, for example. These surface treatments are appropriately selected according to the type of the resin component constituting the base sheet 1, and preferably a corona discharge treatment method from the viewpoints of effects and operability.

  In addition, the base material sheet 1 may be colored with a colorant or the like, painted for adjusting the color, formation of a pattern for imparting design properties, or the like.

  Although the thickness of the base material sheet 1 is selected according to a use, it is about 0.05-1.0 mm normally, and when considering the cost etc., about 0.1-0.7 mm is common.

[Surface protective layer 2]
In the present invention, the surface protective layer 2 constitutes the surface of the decorative sheet and contains at least a polycarbonate (meth) acrylate and inorganic particles having a primary particle diameter of 0.25 μm or less, and an ionizing radiation curable resin. It consists of the hardened | cured material of a composition. Furthermore, in this invention, the index value of content of the inorganic particle in the surface protective layer 2 calculated by the following formula is in the range of 2.5 × 10 ^{−4 to} 25 × 10 ⁻⁴ or less.

(Index value of the content of the inorganic particles in the surface protective layer)
Index value of content of inorganic particles = primary particle diameter of the inorganic particles (μm) × (mass of the inorganic particles (g) / mass of ionizing radiation curable resin contained in the surface protective layer (g)) ÷ the above Surface protective layer thickness (μm)

  Here, the ionizing radiation curable resin composition refers to a composition containing an ionizing radiation curable resin. The ionizing radiation curable resin refers to a resin having an energy quantum capable of crosslinking and polymerizing molecules in an electromagnetic wave or a charged particle beam, that is, a resin that is crosslinked and cured by irradiation with ultraviolet rays or electron beams.

  The inorganic particles are not particularly limited, but the viewpoint of further effectively suppressing cracks in the surface protective layer due to molding in a high temperature environment while improving the scratch resistance, and further exhibiting excellent three-dimensional formability Preferably include metal particles such as silica particles (colloidal silica, fumed silica, precipitated silica, etc.), alumina particles, zirconia particles, titania particles, zinc oxide particles, silica particles and alumina particles are preferred, Silica particles are particularly preferable.

  The primary particle diameter of the inorganic particles is not particularly limited as long as it is 0.25 μm or less, but from the above viewpoint, it is preferably about 0.05 to 0.20 μm, more preferably 0.05 to 0.10 μm. Degree. The primary particle size of the inorganic particles is randomly selected by observing a cross section in the thickness direction of the surface protective layer with a scanning electron microscope (SEM) under the conditions of an acceleration voltage of 3.0 kV and an enlargement magnification of 50,000 times. The average value which measured the particle diameter about the non-aggregate of 100 inorganic particles which were done is meant.

Further, the index value of the content of the inorganic particles in the surface protective layer 2 may be in the range of 2.5 × 10 ^{−4 to} 25 × 10 ⁻⁴ , but from the above viewpoint, preferably 5 .0 × 10 ^-4 ~20.0 × 10 ^-4, and more preferably about include about ^{5.0 × 10 -4 ~15.0 × 10 -4} .

  The mass ratio of the polycarbonate (meth) acrylate resin and the inorganic particles contained in the ionizing radiation curable resin composition forming the surface protective layer 2 is not particularly limited, but from the above viewpoint, preferably 100: About 5-100: 50, More preferably, it is about 100: 5-100: 30, More preferably, about 100: 10-100: 30 is mentioned.

  Moreover, it is preferable that the ionizing radiation curable resin composition which forms the surface protective layer 2 contains at least polycarbonate (meth) acrylate and polyfunctional (meth) acrylate. Furthermore, the mass ratio of the polycarbonate (meth) acrylate and the polyfunctional (meth) acrylate (polycarbonate (meth) acrylate: polyfunctional (meth) acrylate) is preferably about 98: 2 to 70:30. When the mass ratio of the polycarbonate (meth) acrylate and the polyfunctional (meth) acrylate is in such a range, the three-dimensional formability can be improved while improving the scratch resistance of the decorative sheet.

  The polycarbonate (meth) acrylate is not particularly limited as long as it has a carbonate bond in the polymer main chain and has (meth) acrylate in the terminal or side chain. This (meth) acrylate preferably has two or more functional groups from the viewpoint of crosslinking and curing. The polycarbonate (meth) acrylate may be, for example, urethane (meth) acrylate having a polycarbonate skeleton.

  Said polycarbonate (meth) acrylate is obtained by converting a part or all of the hydroxyl group of polycarbonate polyol into (meth) acrylate (acrylic acid ester or methacrylic acid ester), for example. This esterification reaction can be performed by a normal esterification reaction. For example, 1) a method of condensing polycarbonate polyol and acrylic acid halide or methacrylic acid halide in the presence of a base, 2) a method of condensing polycarbonate polyol and acrylic acid anhydride or methacrylic acid anhydride in the presence of a catalyst, Or 3) the method of condensing polycarbonate polyol and acrylic acid or methacrylic acid in the presence of an acid catalyst.

  The polycarbonate polyol is a polymer having a carbonate bond in the polymer main chain and having 2 or more, preferably 2 to 50, more preferably 3 to 50 hydroxyl groups at the terminal or side chain. A typical method for producing this polycarbonate polyol is a method by a polycondensation reaction from a diol compound (A), a trihydric or higher polyhydric alcohol (B), and a compound (C) to be a carbonyl component.

The diol compound (A) used as a raw material is represented by the general formula HO—R ¹ —OH. Here, R ¹ is a divalent hydrocarbon group having 2 to 20 carbon atoms, and the group may contain an ether bond. For example, a linear or branched alkylene group, a cyclohexylene group, or a phenylene group.

  Specific examples of the diol compound include ethylene glycol, 1,2-propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, neopentyl glycol, 1,3-propanediol, 1,4-butanediol, , 5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,3-bis (2-hydroxyethoxy) benzene, 1,4-bis (2 -Hydroxyethoxy) benzene, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like. These diols may be used alone or in admixture of two or more.

  Examples of the trihydric or higher polyhydric alcohol (B) include alcohols such as trimethylolpurpan, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, glycerin and sorbitol. Furthermore, alcohols having a hydroxyl group in which 1 to 5 equivalents of ethylene oxide, propylene oxide, or other alkylene oxide are added to the hydroxyl group of these polyhydric alcohols may be used. These polyhydric alcohols may be used alone or in combination of two or more.

  The compound (C) serving as the carbonyl component is any compound selected from carbonic acid diesters, phosgene, and equivalents thereof. Specific examples thereof include carbonic acid diesters such as dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, diphenyl carbonate, ethylene carbonate and propylene carbonate, phosgene, and halogenated formates such as methyl chloroformate, ethyl chloroformate and phenyl chloroformate. Etc. These may be used alone or in admixture of two or more.

  The polycarbonate polyol is synthesized by subjecting the above-described diol compound (A), a trihydric or higher polyhydric alcohol (B), and a compound (C) to be a carbonyl component to a polycondensation reaction under general conditions. . For example, the charged molar ratio of the diol compound (A) to the polyhydric alcohol (B) is preferably in the range of 50:50 to 99: 1, and the diol compound (C) as the carbonyl component ( The charged molar ratio of A) to the polyhydric alcohol (B) is preferably 0.2 to 2 equivalents with respect to the hydroxyl group of the diol compound and polyhydric alcohol.

  The number of equivalents (eq./mol) of hydroxyl groups present in the polycarbonate polyol after the polycondensation reaction at the charge ratio is 3 or more, preferably 3 to 50, more preferably 3 20. Within this range, a necessary amount of (meth) acrylate groups are formed by the esterification reaction described later, and moderate flexibility is imparted to the polycarbonate (meth) acrylate resin. The terminal functional group of this polycarbonate polyol is usually an OH group, but a part thereof may be a carbonate group.

  The method for producing the polycarbonate polyol described above is described in, for example, JP-A No. 64-1726. The polycarbonate polyol can also be produced by an ester exchange reaction between a polycarbonate diol and a trihydric or higher polyhydric alcohol as described in JP-A-3-181517.

  The urethane (meth) acrylate having the above polycarbonate skeleton can be easily produced, for example, by reacting a polycarbonate polyol, an organic polyisocyanate compound, and hydroxy (meth) acrylate.

  The molecular weight of the polycarbonate (meth) acrylate used in the present invention is preferably 500 or more, more preferably 1,000 or more, as measured by GPC analysis and converted to standard polystyrene. More preferably, it exceeds 2,000. The upper limit of the weight average molecular weight of the polycarbonate (meth) acrylate is not particularly limited, but is preferably 100,000 or less and more preferably 50,000 or less from the viewpoint of controlling the viscosity not to be too high. From the viewpoint of achieving both scratch resistance and three-dimensional formability, it is more preferably more than 2,000 and not more than 60,000, and particularly preferably 5,000 to 40,000.

  Moreover, polyfunctional (meth) acrylate should just be bifunctional or more (meth) acrylate, and there is no restriction | limiting in particular. However, trifunctional or higher functional (meth) acrylates are preferred from the viewpoint of curability. Here, bifunctional means having two ethylenically unsaturated bonds {(meth) acryloyl group} in the molecule.

  The polyfunctional (meth) acrylate may be either an oligomer or a monomer, but a polyfunctional (meth) acrylate oligomer is preferable from the viewpoint of improving scratch resistance.

  Examples of the polyfunctional (meth) acrylate oligomer include urethane (meth) acrylate oligomers, epoxy (meth) acrylate oligomers, polyester (meth) acrylate oligomers, and polyether (meth) acrylate oligomers. Here, the urethane (meth) acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by the reaction of polyether polyol or polyester polyol and polyisocyanate with (meth) acrylic acid. The epoxy (meth) acrylate oligomer can be obtained, for example, by reacting (meth) acrylic acid with an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolak type epoxy resin and esterifying it. Further, a carboxyl-modified epoxy (meth) acrylate oligomer obtained by partially modifying this epoxy (meth) acrylate oligomer with a dibasic carboxylic acid anhydride can also be used. Examples of polyester (meth) acrylate oligomers include esterification of hydroxyl groups of polyester oligomers having hydroxyl groups at both ends obtained by condensation of polycarboxylic acid and polyhydric alcohol with (meth) acrylic acid, It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a carboxylic acid with (meth) acrylic acid. The polyether (meth) acrylate oligomer can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid.

  Furthermore, other polyfunctional (meth) acrylate oligomers include polybutadiene (meth) acrylate oligomers with high hydrophobicity having (meth) acrylate groups in the side chain of polybutadiene oligomers, and silicones (meta-methacrylate) having polysiloxane bonds in the main chain. ) Acrylate oligomers, aminoplast resin (meth) acrylate oligomers obtained by modifying aminoplast resins having many reactive groups in small molecules.

  The polyfunctional (meth) acrylate monomers are specifically ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified di Cyclopentenyl di (meth) acrylate, ethylene oxide modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylol proppant (Meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylol Propane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, caprolactone modified Examples include dipentaerythritol hexa (meth) acrylate.

  As the polyfunctional (meth) acrylate, a silicone-modified urethane (meth) acrylate oligomer is preferable. In the present invention, the ionizing radiation curable resin composition is preferably composed of a cured product of an ionizing radiation curable resin composition further containing a silicone-modified urethane (meth) acrylate oligomer in addition to the polycarbonate (meth) acrylate. .

  The polyfunctional (meth) acrylate oligomer and polyfunctional (meth) acrylate monomer described above may be used alone or in combination of two or more.

  In the present invention, a monofunctional (meth) acrylate can be used in combination with the polyfunctional (meth) acrylate as long as the object of the present invention is not impaired, for the purpose of lowering the viscosity. Examples of monofunctional (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl ( Examples include meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, and (meth) acryloylmorpholine. These monofunctional (meth) acrylates may be used alone or in combination of two or more.

  When using an ultraviolet curable resin composition as the ionizing radiation curable resin composition, it is desirable to add about 0.1 to 5 parts by mass of the photopolymerization initiator to 100 parts by mass of the ultraviolet curable resin. . The initiator for photopolymerization can be appropriately selected from those conventionally used, and is not particularly limited. For example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin Isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- Hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2 (hydroxy-2-propyl) ketone, Nzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, Examples include 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal and the like.

  Moreover, as a photosensitizer, p-dimethylbenzoic acid ester, tertiary amines, a thiol type sensitizer, etc. can be used, for example.

  In the present invention, it is preferable to use an electron beam curable resin composition as the ionizing radiation curable resin composition. This is because the electron beam curable resin composition can be made solvent-free, is more preferable from the viewpoint of environment and health, and does not require a photopolymerization initiator, and can provide stable curing characteristics.

  Moreover, in addition to the said inorganic particle, various additives can further be mix | blended with the ionizing radiation-curable resin composition which comprises the surface protective layer 2 in this invention according to the desired physical property of the cured resin layer obtained. it can. Examples of this additive include a weather resistance improver, an abrasion resistance improver, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, an adhesion improver, a leveling agent, a thixotropic agent, a coupling agent, A plasticizer, an antifoamer, a filler, a solvent, a coloring agent, etc. are mentioned.

  Here, as the weather resistance improving agent, an ultraviolet absorber or a light stabilizer can be used. The ultraviolet absorber may be either inorganic or organic. As the inorganic ultraviolet absorber, titanium dioxide, cerium oxide, zinc oxide or the like having an average particle size of about 5 to 120 nm can be preferably used. Examples of the organic ultraviolet absorber include benzotriazole-based compounds, specifically 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-). Amylphenyl) benzotriazole, 3- [3- (benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propionic acid ester of polyethylene glycol, and the like. On the other hand, examples of the light stabilizer include hindered amines, specifically 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2′-n-butylmalonate bis (1,2,2). , 6,6-pentamethyl-4-piperidyl), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl)- 1,2,3,4-butanetetracarboxylate and the like. Further, as the ultraviolet absorber or light stabilizer, a reactive ultraviolet absorber or light stabilizer having a polymerizable group such as a (meth) acryloyl group in the molecule can be used. Moreover, it can also be copolymerized and used to such an extent that the performance (scratch resistance and three-dimensional moldability) as a surface protective layer of the polymer of this invention is not impaired.

  Examples of the polymerization inhibitor include hydroquinone, p-benzoquinone, hydroquinone monomethyl ether, pyrogallol, and t-butylcatechol. Examples of the crosslinking agent include a polyisocyanate compound, an epoxy compound, a metal chelate compound, an aziridine compound, and an oxazoline compound. Used.

  As the filler, for example, barium sulfate, talc, clay, calcium carbonate, aluminum hydroxide and the like are used.

  Examples of the colorant include known coloring pigments such as quinacridone red, isoindolinone yellow, phthalocyanine blue, phthalocyanine green, titanium oxide, and carbon black.

  As the infrared absorber, for example, a dithiol metal complex, a phthalocyanine compound, a diimmonium compound, or the like is used.

  The surface protective layer 2 can be formed by preparing a coating liquid containing the above-mentioned ionizing radiation curable resin composition, applying it, and crosslinking and curing it. In addition, the viscosity of a coating liquid should just be a viscosity which can form a non-hardened resin layer on the surface of a base material by the below-mentioned coating system, and there is no restriction | limiting in particular.

  In the present invention, the prepared coating liquid is a known method such as gravure coating, bar coating, roll coating, reverse roll coating, comma coating, etc., preferably so that the thickness after curing is 1-1000 μm, preferably It is applied by gravure coating to form an uncured resin layer.

  In the present invention, the uncured resin layer thus formed is irradiated with ionizing radiation such as an electron beam and ultraviolet rays to cure the uncured resin layer. Here, when an electron beam is used as the ionizing radiation, the acceleration voltage can be appropriately selected according to the resin used and the thickness of the layer, but the uncured resin layer is usually cured at an acceleration voltage of about 70 to 300 kV. preferable.

  In addition, in electron beam irradiation, the transmission capability increases as the acceleration voltage increases. Therefore, when a base material that deteriorates due to an electron beam is used as the base material sheet 1, the penetration depth of the electron beam and the thickness of the resin layer are used. By selecting the accelerating voltage so that the two are substantially equal, it is possible to suppress the irradiation of the extra electron beam to the base material sheet 1, and to minimize the deterioration of the base material due to the excess electron beam. Can do.

  The irradiation dose is preferably such that the crosslink density of the resin layer is saturated, and is usually selected in the range of 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 50 kGy (1 to 5 Mrad).

  Further, the electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. Can be used.

  When ultraviolet rays are used as the ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are emitted. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp, etc. are used.

  The cured resin layer thus formed has various functions by adding various additives, for example, high hardness and scratch resistance, so-called hard coat function, anti-fogging coating function, anti-fouling coating. A function, an antiglare coating function, an antireflection coating function, an ultraviolet shielding coating function, an infrared shielding coating function and the like can also be imparted.

  In this invention, it is preferable that the thickness after the hardening of the surface protective layer 2 is 1-1000 micrometers. If the thickness of the surface protective layer 2 after curing is 1 μm or more, sufficient physical properties as a protective layer such as scratch resistance and weather resistance can be obtained. On the other hand, when the thickness of the surface protective layer 2 after curing is 1000 μm or less, it is easy to uniformly apply ionizing radiation, and uniform curing is easily obtained, which is economically advantageous.

  Further, the thickness of the surface protective layer 2 after curing is more preferably 1 to 50 μm, and further preferably 1 to 30 μm, so that the three-dimensional formability is improved, and a complicated three-dimensional shape such as an automobile interior use is obtained. High followability can be obtained. Therefore, in the decorative sheet of the present invention, even if a hard ionizing radiation curable resin is blended, excellent three-dimensional formability can be expressed, and the coating film is hardened without impairing the three-dimensional formability. Therefore, it is possible to provide excellent scratch resistance that is preferable in terms of processing and practical use.

  The decorative sheet of the present invention is required to have a high film thickness particularly for the surface protective layer because sufficiently high three-dimensional formability can be obtained even if the thickness of the surface protective layer 2 is made thicker than the conventional one. It is also useful as a decorative sheet for a member such as a vehicle exterior part.

[Primer layer 3]
The primer layer 3 is a layer that is included as necessary for the purpose of improving the adhesion between the surface protective layer 2 and the layer located therebelow. The primer layer 3 can be formed of a resin.

  The primer composition constituting the primer layer 3 is (meth) acrylic resin, urethane resin, (meth) acrylic / urethane copolymer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, butyral resin, chlorinated polypropylene, Chlorinated polyethylene or the like is used.

  (Meth) acrylic resins include (meth) acrylic acid ester homopolymers, copolymers of two or more different (meth) acrylic acid ester monomers, or (meth) acrylic acid esters and other monomers. Polymers, and specifically, poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate propyl, poly (meth) acrylate butyl, methyl (meth) acrylate (Meth) butyl acrylate copolymer, (meth) ethyl acrylate / (meth) butyl acrylate copolymer, ethylene / (meth) methyl acrylate copolymer, styrene / methyl (meth) acrylate copolymer A (meth) acrylic resin composed of a homopolymer or a copolymer containing a (meth) acrylic acid ester such as is preferably used.

  As the urethane resin, polyurethane having a polyol (polyhydric alcohol) as a main ingredient and an isocyanate as a crosslinking agent (curing agent) can be used. As the polyol, one having two or more hydroxyl groups in the molecule, for example, polyester polyol, polyethylene glycol, polypropylene glycol, acrylic polyol, polyether polyol and the like are used. Examples of the isocyanate include polyvalent isocyanate having two or more isocyanate groups in the molecule, aromatic isocyanate such as 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate. Aliphatic (or alicyclic) isocyanates such as are used. It is also possible to mix urethane resin and butyral resin.

  As the (meth) acryl / urethane copolymer resin, for example, an acrylic / urethane (polyester urethane) block copolymer resin is preferable. As the curing agent, the above-mentioned various isocyanates are used. The acrylic / urethane (polyester urethane) block copolymer resin may have an acrylic / urethane ratio (mass ratio) of preferably (9/1) to (1/9), more preferably (8/2) to (2). Since it can be adjusted within the range of / 8) and used for various decorative sheets, it is particularly preferable as a resin used in the primer composition.

  The thickness of the primer layer 3 is preferably about 0.1 to 10 μm. When it is 0.1 μm or more, the effect of preventing the surface protective layer from cracking, breaking, whitening, etc. can be sufficiently exerted. On the other hand, if the thickness of the primer layer is 10 μm or less, it is preferable that the three-dimensional formability does not fluctuate since the drying and curing of the coating film is stable when the primer layer is applied.

  Primer layer 3 includes gravure coat, gravure reverse coat, gravure offset coat, spinner coat, roll coat, reverse roll coat, kiss coat, wheeler coat, dip coat, silk screen solid coat, wire bar coat, flow coat, comma coat, coat It is formed by a usual coating method such as sink coating, brush coating, spray coating, or transfer coating method. The transfer coating method is a method in which a coating film of the primer layer 3 or the back surface adhesive layer is once formed on a thin sheet (film base material) and then coated on the target layer surface in the decorative sheet.

[Picture layer 4]
The pattern layer 4 is a layer which is provided on the base material sheet 1 as necessary and gives decorativeness to the decorative sheet. The pattern layer 4 is formed, for example, by printing various patterns using ink and a printing machine. The pattern formed by the pattern layer 4 is not particularly limited. For example, a grain pattern simulating the surface of a rock such as a grain pattern, a marble pattern (for example, a travertine marble pattern), a cloth simulating a texture or a cloth pattern Patterns, tiled patterns, brickwork patterns, etc., and patterns such as marquetry and patchwork that combine these are also included. These patterns can be formed by multicolor printing with normal yellow, red, blue and black process colors, or by multicolor printing with special colors prepared by preparing individual color plates constituting the pattern. It is formed.

  As the pattern ink used for the pattern layer 4, a binder appropriately mixed with a colorant such as a pigment or dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, or a curing agent is used. The binder is not particularly limited, and examples thereof include polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-acrylic copolymer resins, chlorinated polypropylene resins, acrylic resins, Examples thereof include polyester resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, and cellulose acetate resins. These resins may be used alone or in combination of two or more.

  The colorant is not particularly limited. For example, carbon black (black), iron black, titanium white, antimony white, chrome yellow, titanium yellow, petal, cadmium red, ultramarine, cobalt blue, and other inorganic pigments, quinacridone red Organic pigments or dyes such as isoindolinone yellow and phthalocyanine blue, metallic pigments composed of scaly foils such as aluminum and brass, pearl luster composed of scaly foils such as titanium dioxide-coated mica and basic lead carbonate (pearl) ) Pigments.

  The pattern layer 4 is formed by a normal printing method such as gravure printing. The pattern layer 4 is formed by a normal printing method such as gravure printing or a normal coating method such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, and reverse roll coating.

  Although the thickness in particular of the pattern layer 4 is not restrict | limited, For example, about 1-30 micrometers, Preferably about 1-20 micrometers is mentioned.

[Hidden layer]
If the hiding layer is provided with a pattern layer 4 between the base sheet 1 and the surface protective layer 2 for the purpose of suppressing color change and variation of the base sheet 1, the base sheet 1 and the pattern layer 4 are provided. It is a layer provided as needed, for example.

  Since the concealing layer is provided to suppress the base sheet 1 from adversely affecting the color tone and pattern of the decorative sheet, it is generally formed as an opaque layer.

  The concealing layer is formed using an ink composition in which a binder, a colorant such as a pigment and a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, and a curing agent are appropriately mixed. The ink composition for forming the concealing layer is appropriately selected from those used for the picture layer 4 described above.

  The concealing layer is usually set to a thickness of about 1 to 20 μm and is desirably formed as a so-called solid printing layer.

[Back adhesive layer]
In order that the decorating sheet of this invention may improve adhesiveness with injection resin, the back surface (surface on the opposite side to the surface protection layer 2) back surface adhesive layer (not shown) of a decorating sheet may be provided if desired. it can. A thermoplastic resin or a curable resin is used for the back surface adhesive layer depending on the injection resin. Examples of thermoplastic resins include acrylic resins, acrylic-modified polyolefin resins, chlorinated polyolefin resins, vinyl chloride-vinyl acetate copolymers, thermoplastic urethane resins, thermoplastic polyester resins, polyamide resins, rubber resins, and the like. Can be used alone or in combination of two or more. Examples of the thermosetting resin include urethane resin and epoxy resin.

  The thickness of the back surface adhesive layer is preferably about 0.1 to 10 μm. Further, the back surface adhesive layer can be formed in the same manner as the method exemplified for the primer layer 3.

2. Decorated resin molded product The decorated resin molded product of the present invention is, as shown in FIG. 3, a decorated resin comprising a molded resin (molded resin layer 5) and a surface protective layer 2 provided on the molded resin. The molded article, wherein the surface protective layer 2 comprises a cured product of an ionizing radiation curable resin composition containing at least polycarbonate (meth) acrylate and inorganic particles having a primary particle size of 0.25 μm or less, The index value of the content of the inorganic particles in the surface protective layer, calculated by the formula (2), is 2.5 × 10 ⁻⁴ or more and 25 × 10 ⁻⁴ or less. The decorative resin molded product of the present invention can be manufactured in a process by, for example, integrating the decorative sheet and the molded resin of the present invention. As described above, at least one layer of the base material sheet 1, the primer layer 3, the pattern layer 4, the concealing layer, the back surface adhesive layer, and the like may be further provided on the decorative resin molded product.

  The decorative resin molded product of the present invention is produced, for example, by various injection molding methods such as insert molding, simultaneous injection molding, blow molding, and gas injection molding using the decorative sheet of the present invention. The Among these injection molding methods, an insert molding method and an injection molding simultaneous decorating method are preferable. In addition, the decorative resin molded product of the present invention is a decorative method of sticking the decorative sheet of the present invention on a prepared three-dimensional resin molded body (molded resin layer 5) such as a vacuum pressure bonding method. Can also be produced.

  In the insert molding method, first, in the vacuum forming step, the decorative sheet of the present invention is vacuum formed (off-line pre-molding) into a molded product surface shape in advance by a vacuum forming die, and then an excess portion is trimmed as necessary. A molded sheet is obtained. This molded sheet is inserted into an injection mold, the injection mold is clamped, a resin in a fluid state is injected into the mold from the base sheet side, solidified, and simultaneously with the injection molding, on the outer surface of the resin molded product A decorative resin molded product is manufactured by integrating the decorative sheet.

More specifically, the decorative resin molded product of the present invention is manufactured by an insert molding method including the following steps.
A vacuum forming step of forming the decorative sheet of the present invention into a three-dimensional shape in advance by a vacuum forming die,
Trimming process to trim the excess part of the vacuum-decorated decorative sheet to obtain the molded sheet, and insert the molded sheet into the injection mold, close the injection mold, and inject the fluid resin from the base sheet side An integration process in which the resin and the molded sheet are integrated by injection into the mold.

  In the vacuum forming step in the insert molding method, the decorative sheet may be heated and molded. The heating temperature at this time is not particularly limited, and may be appropriately selected depending on the type of resin constituting the decorative sheet, the thickness of the decorative sheet, and the like, for example, when an ABS resin film is used as the base sheet. For example, the temperature is usually about 100 to 250 ° C, preferably about 130 to 200 ° C. Moreover, in the integration step, the temperature of the resin in a fluid state is not particularly limited, but is usually about 180 to 320 ° C, preferably about 220 to 280 ° C.

  In addition, in the simultaneous injection molding decoration method, the decorative sheet of the present invention is placed in a female mold that also serves as a vacuum forming mold provided with a suction hole for injection molding, and preliminary molding (in-line preliminary molding) is performed with this female mold. After the injection mold is clamped, the resin in a fluid state is injected and filled into the mold from the base sheet side, solidified, and decorated on the outer surface of the resin molding simultaneously with the injection molding. A decorative resin molded product is manufactured by integrating the sheets.

More specifically, the decorative resin molded product of the present invention is manufactured by the simultaneous injection molding method including the following steps.
After the decorative sheet of the present invention is installed so that the surface of the base sheet of the decorative sheet faces the molding surface of the movable mold having a molding surface of a predetermined shape, the decorative sheet is heated, A pre-molding step of pre-molding the decorative sheet by softening and vacuum-sucking from the movable mold side and bringing the softened decorative sheet into close contact with the molding surface of the movable mold,
After clamping the movable mold and the fixed mold having the decorative sheet closely adhered along the molding surface, the fluidized resin is injected from the base sheet side into the cavity formed by both molds. Filling and solidifying to form a resin molded body, integrating the resin molded body and the decorative sheet by stacking and integrating, and moving the movable mold away from the fixed mold, the entire decorative sheet is laminated The extraction process of taking out the molded resin product.

  In the preforming step of the simultaneous injection molding method, the heating temperature of the decorative sheet is not particularly limited, and may be appropriately selected depending on the type of resin constituting the decorative sheet, the thickness of the decorative sheet, etc. If a polyester resin film or an acrylic resin film is used as the base sheet, the temperature can usually be about 70 to 130 ° C. In the injection molding process, the temperature of the resin in the fluidized state is not particularly limited, but is usually about 180 to 320 ° C, preferably about 220 to 280 ° C.

  In the vacuum bonding method, first, the decorative sheet and the resin molded body of the first pressure chamber located on the upper side and the second vacuum chamber located on the lower side in the vacuum pressure bonding machine, the decorative sheet is the first. Install in the vacuum press so that the vacuum chamber side, the resin molded body becomes the second vacuum chamber side, and the base sheet side of the decorative sheet face the resin molded body side, and the two vacuum chambers are in a vacuum state . The resin molding is installed on a lifting platform that is provided on the second vacuum chamber side and can be moved up and down. Next, while pressurizing the first vacuum chamber, the molded body is pressed against the decorative sheet using an elevator, and the resin molded body is stretched while stretching the decorative sheet using the pressure difference between the two vacuum chambers. Adhere to the surface. Finally, the two vacuum chambers are opened to the atmospheric pressure, and the decorative resin molded product of the present invention can be obtained by trimming the excess portion of the decorative sheet as necessary.

  In the vacuum pressure bonding method, it is preferable to include a step of heating the decorative sheet in order to soften the decorative sheet and improve the formability before the step of pressing the molded body against the decorative sheet. The vacuum pressure bonding method provided with the said process may be especially called a vacuum thermocompression bonding method. Although the heating temperature in the said process should just be suitably selected with the kind of resin which comprises a decorating sheet, the thickness of a decorating sheet, etc., if it is a case where a polyester resin film or an acrylic resin film is used as a base material sheet Usually, it can be about 60-200 degreeC.

  In the decorative resin molded product of the present invention, the molded resin layer 5 may be formed by selecting a resin corresponding to the application. The resin forming the molded resin layer 5 may be a thermoplastic resin or a thermosetting resin.

  Examples of the thermoplastic resin include polyolefin resins such as polyethylene and polypropylene, ABS resins, styrene resins, polycarbonate resins, acrylic resins, and vinyl chloride resins. These thermoplastic resins may be used individually by 1 type, and may be used in combination of 2 or more type.

  Moreover, as a thermosetting resin, a urethane resin, an epoxy resin, etc. are mentioned, for example. These thermosetting resins may be used individually by 1 type, and may be used in combination of 2 or more type.

  The surface of the decorative resin molded body produced as described above has high scratch resistance.

  The decorative resin molded product of the present invention includes, for example, interior materials or exterior materials for vehicles such as automobiles; fittings such as window frames and door frames; interior materials for buildings such as walls, floors, and ceilings; television receivers and air conditioners. It can be used as a housing for home appliances such as a machine;

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

<Examples 1-9 and Comparative Examples 1-4>
(Preparation of decorative sheet)
An ABS resin film (flexural modulus: 2000 MPa, thickness: 400 μm) was used as a base sheet, and a woodgrain pattern layer was formed on the surface of the film by gravure printing using an acrylic resin composition. Next, a primer layer made of an acrylic resin (acrylic ester homopolymer) was applied to the surface of the pattern layer by gravure coating. The thickness of the primer layer was 3 μm. Next, an electron beam curable resin composition having the composition shown in Table 1 is applied to the surface of the primer layer by gravure coating so that the thickness (μm) after curing of the resin composition becomes the value shown in Table 1. did. Details of the resins and particles described in Table 1 are as described later. This uncured resin layer was irradiated with an electron beam having an acceleration voltage of 165 kV and an irradiation dose of 50 kGy (5 Mrad) to cure the electron beam curable resin composition to obtain each decorative sheet. Each decorative sheet was evaluated as follows. The evaluation results are shown in Table 1.

(Evaluation of formability in high temperature environment)
By the following method, each decorative sheet obtained above is stretched at a stretching ratio of 250% at 110 ° C., and whether or not cracks are generated in the surface protective layer is obtained under a high temperature environment. The moldability was evaluated. First, a decorative sheet (MD 120 mm × TD 30 mm) is fixed to the chucking part of Tensilon manufactured by Orient. Next, it hold | maintains for 1 minute at environmental temperature 110 degreeC, and makes the surface temperature of a decorating sheet 110 degreeC. Next, it is stretched from the initial chuck distance (10 mm) to 250% (35 mm) under the condition of a test speed of 50 mm / min. Stop in the stretched state of 250%, hold it for 1 minute, and check for cracks in the surface protective layer. The evaluation criteria are as follows.
A: No cracks were observed in the surface protective layer, and the appearance was good.
B: Slight cracks were observed in the surface protective layer after 1 minute with 250% extended, but there was no practical problem.
C: Before reaching 250% elongation, cracks started to appear in the surface protective layer, and when reaching 250% elongation, cracks having practical problems were observed.

(Three-dimensional formability)
Each decorative sheet obtained above was heated to 160 ° C. and softened using an infrared heater. Next, vacuum forming was performed using a vacuum forming die (maximum draw ratio: 250%), and the decorative sheet was formed into the internal shape of the die. After cooling the decorative sheet, the decorative sheet was released from the mold. The surface state of the decorative sheet after molding was visually observed, and the moldability was evaluated according to the following criteria. The results are shown in Table 1.
A: The surface of the surface protective layer was good in appearance with no cracks or whitening.
B: Slight cracks and whitening were observed at the maximum stretched portion of the surface protective layer, but there were no practical problems.
C: Practically problematic cracks and whitening were observed in the maximum stretched portion of the surface protective layer.

(Scratch resistance)
Using # 0000 steel wool, the appearance after the surface of the surface protective layer of each decorative sheet obtained above was rubbed 5 times with a load of 500 gf was evaluated according to the following criteria.
A ⁺ : The scratch formed on the surface of the surface protective layer was repaired within 1 minute, and no scratch was left on the surface of the surface protective layer.
A: The scratch formed on the surface of the surface protective layer was repaired within 5 minutes, and no scratch was left on the surface of the surface protective layer.
B: Although slight scratches remained on the surface of the surface protective layer, there was no practical problem.
C: Scratches having practical problems remained on the surface of the surface protective layer.

Details of resin 1, resin 2, particle 1, particle 2, and particle 3 shown in Table 1 are as follows.
Resin 1: Bifunctional urethane acrylate having a polycarbonate skeleton, weight average molecular weight 30,000
Resin 2: Silicone-modified hexafunctional urethane acrylate, weight average molecular weight 3,000
Particle 1: Silica particles having an average primary particle size of 0.05 μm 2: Silica particles having an average primary particle size of 0.10 μm 3: Silica particles having an average primary particle size of 0.20 μm

As shown in Table 1, the surface protective layer comprises a cured product of an ionizing radiation curable resin composition containing polycarbonate (meth) acrylate and inorganic particles having a primary particle diameter of 0.25 μm or less, The decorative sheet of Examples 1 to 9 in which the index value of the content of the inorganic particles in the protective layer is in the range of 2.5 × 10 ^{−4 to} 25 × 10 ⁻⁴ has excellent scratch resistance. Furthermore, it can be seen that cracks in the surface protective layer due to three-dimensional molding in a high-temperature environment are effectively suppressed, and excellent three-dimensional moldability is provided.

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Surface protective layer 3 ... Primer layer 4 ... Pattern layer 5 ... Molding resin layer

Claims (4)

At least a decorative sheet comprising a base sheet and a surface protective layer provided on the base sheet,
The surface protective layer comprises a cured product of an ionizing radiation curable resin composition containing at least polycarbonate (meth) acrylate and inorganic particles having a primary particle diameter of 0.25 μm or less,
Is calculated by the following equation, the index value of the content of the inorganic particles in the surface protective layer is, 2.5 × 10 ^-4 or more and 25 × 10 ^-4 or less, the decorative sheet.
Index value of content of inorganic particles = primary particle diameter of the inorganic particles (μm) × (mass of the inorganic particles (g) / mass of ionizing radiation curable resin contained in the surface protective layer (g)) ÷ the above Surface protective layer thickness (μm)   The decorative sheet according to claim 1, wherein a mass ratio of the polycarbonate (meth) acrylate resin and the inorganic particles contained in the ionizing radiation curable resin composition is 100: 5 to 100: 50.   The decorative sheet according to claim 1 or 2, wherein the inorganic particles are silica particles. At least a decorative resin molded product comprising a molded resin and a surface protective layer provided on the molded resin,
The surface protective layer comprises a cured product of an ionizing radiation curable resin composition containing at least polycarbonate (meth) acrylate and inorganic particles having a primary particle diameter of 0.25 μm or less,
The decorative resin molded product, wherein the index value of the content of the inorganic particles in the surface protective layer, calculated by the following formula, is 2.5 × 10 ⁻⁴ or more and 25 × 10 ⁻⁴ or less.
Index value of content of inorganic particles = primary particle diameter of the inorganic particles (μm) × (mass of the inorganic particles (g) / mass of ionizing radiation curable resin contained in the surface protective layer (g)) ÷ the above Surface protective layer thickness (μm)