JP5012434B2 - Decorative sheet, decorative resin molded product manufacturing method, and decorative resin molded product - Google Patents

Description

  The present invention relates to a decorative sheet, a method for manufacturing a decorative resin molded product using the decorative sheet, and a decorative resin molded product manufactured by the manufacturing method.

  A decorative molded product decorated by laminating a decorative sheet on the surface of the molded product is used in various applications such as vehicle interior parts. As a method for molding such a decorative molded product, the decorative sheet is molded into a three-dimensional shape in advance by a vacuum mold, the molded sheet is inserted into an injection mold, and a fluid resin is injected into the mold. The insert molding method (for example, refer to Patent Document 1) for integrating the resin and the molded sheet, and the decorative sheet inserted into the mold during the injection molding are integrated with the molten resin injected into the cavity. There is an injection molding simultaneous decorating method (see, for example, Patent Document 2 and Patent Document 3) that decorates the surface of the resin molded body.

  By the way, the decorative molded product is provided with a surface protective layer for the purpose of improving the wear resistance and scratch resistance of the surface. However, in the molding method of the decorative molded product described above, in the insert molding method, the decorative sheet is formed into a three-dimensional shape in advance by a vacuum mold, and in the injection molding simultaneous decorating method, the decorative sheet is pre-molded or molten resin. In the process of drawing and adhering along the inner peripheral surface of the cavity, the decorative sheet is made to conform to the mold shape by vacuum / pneumatic action, or by pulling by the pressure of molten resin, shear stress, etc. Since it is extended beyond the minimum necessary amount, there has been a problem that cracks occur in the surface protective layer of the curved surface portion of the molded product.

In order to improve the moldability of the surface protective layer, a thermosetting resin has been used as the surface protective layer (for example, see Patent Document 4). The thermosetting resin showed good results for moldability, and the surface protective layer was hardly cracked, but the surface wear resistance and scratch resistance of the decorative molded product were not satisfactory.
In addition, by using an ionizing radiation curable resin such as an ultraviolet curable resin as the surface protective layer and increasing the crosslink density of the resin that forms the surface protective layer of the decorative sheet, the surface wear resistance of the decorative molded product can be increased. Attempts were made to improve the scratch resistance, but there was a problem that cracks occurred in the curved surface of the molded product during molding.
Furthermore, although an ionizing radiation curable resin such as an ultraviolet curable resin is used as a surface protective layer, a method of making it a semi-cured state at the stage of a decorative sheet and completely curing it after decorative molding has been tried (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. In addition, since it is necessary to irradiate the three-dimensional molded product with ultraviolet rays, a separate facility for irradiating the three-dimensional molded product with ultraviolet rays is required.

  In addition, due to the recent trend toward high-end products by consumers, a sense of quality has been demanded for decorative molded products used for vehicle interior parts and the like. Is also important, and it is required to give matte or unevenness to a specific part of the pattern.

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

  In view of the above problems, the present invention is a decorative molded product having high wear resistance and scratch resistance, having a surface protective layer that has good moldability and is free from cracks, and has high design properties. The object is to provide a decorative sheet used for molding, a method for producing a decorative resin molded product using the decorative sheet, and a decorative resin molded product produced by the production method.

  As a result of intensive studies to achieve the above object, the present inventors have obtained a decorative sheet having at least a surface protective layer and a transparent resin layer partially provided on the surface protective layer on a substrate. The surface protective layer is obtained by curing the curable resin composition, the transparent resin layer is obtained by crosslinking and curing a resin composition containing an ionizing radiation curable resin and a thermoplastic resin in a specific ratio, and The inventors have found that the above problem can be solved by setting the thickness of the surface protective layer to a specific thickness. The present invention has been completed based on such findings.

That is, the present invention
(1) A decorative sheet having at least a surface protective layer and a transparent resin layer partially provided on the surface protective layer on a substrate, the surface protective layer comprising an ionizing radiation curable resin and a thermoplastic resin. A curable resin composition containing a ratio (mass ratio) of 75:25 to 25:75 is cured, and the thermoplastic resin used in the surface protective layer is methyl methacrylate and other (meth) acrylic acid esters. It is a copolymer of monomers, and the structural unit derived from other (meth) acrylic acid ester monomer is 0.1 to 200 mol with respect to 100 mol of the structural unit derived from methyl methacrylate in the thermoplastic resin. in the range, the transparent resin layer is an ionizing radiation curable resin and a thermoplastic resin 75: 25-25: This is a resin composition comprising 75 ratio (mass ratio) obtained by crosslinking and curing, the transparent resin layer Used Thermoplastic polystyrene-reduced weight average molecular weight measured by the resin of gel permeation chromatography (GPC) is in the range of 90,000 to 120,000, and the thickness of the surface protective layer is 1~1000μm decorative sheet that,
(2) A vacuum forming step in which the decorative sheet according to (1) is formed into a three-dimensional shape in advance using a vacuum forming die, a step of trimming excess portions to obtain a formed sheet, and inserting the formed sheet into an injection mold. And a method for producing a decorative resin molded product having a step of closing the injection mold, injecting a fluid resin into the mold and integrating the resin and the molded sheet,
(3) After the decorative sheet according to (1) is installed so that the base material of the decorative sheet faces the molding surface of the movable mold having a molding surface with a predetermined shape, Heating and softening the decorative sheet, vacuum suction from the movable mold side, and preliminarily molding the decorative sheet by 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 adhered along the molding surface, the resin molding material in a fluid state is injected and filled into the cavity formed by both molds. An injection molding process in which the formed resin molded body and the decorative sheet are laminated and integrated by solidification, and a resin molding in which the entire decorative sheet is laminated by separating the movable mold from the fixed mold Manufacturing method of decorative resin molded products that sequentially perform the process of removing the body , And (4) above (2) or (3) decorated resin molded article produced by the method described in,
Is to provide.

  The decorative sheet of the present invention has high wear resistance and scratch resistance, has good moldability, and does not cause cracks in the surface protective layer even in the insert molding method and the simultaneous injection molding method. Moreover, high designability can be imparted to the decorative molded product.

The decorative sheet of the present invention has at least a surface protective layer on a substrate and a transparent resin layer partially provided on the surface protective layer, and the surface protective layer is obtained by curing a curable resin composition. And the transparent resin layer is obtained by crosslinking and curing a resin composition containing an ionizing radiation curable resin and a thermoplastic resin in a ratio (mass ratio) of 75:25 to 25:75, and the thickness of the surface protective layer is It is 1-1000 micrometers.
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. Specifically, it can be appropriately selected from polymerizable monomers, polymerizable oligomers, or prepolymers conventionally used as ionizing radiation curable resins.

  Typically, a (meth) acrylate monomer having a radical polymerizable unsaturated group in the molecule is suitable as the polymerizable monomer, and among them, a polyfunctional (meth) acrylate is preferable. Here, “(meth) acrylate” means “acrylate or methacrylate”, and other similar ones have the same meaning. The polyfunctional (meth) acrylate is not particularly limited as long as it is a (meth) acrylate having two or more ethylenically unsaturated bonds in the molecule. 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, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified diphosphate ( (Meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylo Propane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane 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 dipentaerythritol hexa (meth) acrylate, etc. Is mentioned. These polyfunctional (meth) acrylates may be used singly 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, and isobornyl (meth) acrylate. These monofunctional (meth) acrylates may be used alone or in combination of two or more.

  Next, as the polymerizable oligomer, an oligomer having a radical polymerizable unsaturated group in the molecule, for example, epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate The system etc. are mentioned. Here, 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. The urethane (meth) acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reaction of polyether polyol or polyester polyol and polyisocyanate with (meth) acrylic acid. 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 polymerizable oligomers include polybutadiene (meth) acrylate oligomers with high hydrophobicity that have (meth) acrylate groups in the side chain of polybutadiene oligomers, and silicone (meth) acrylate oligomers that have polysiloxane bonds in the main chain. In a molecule such as an aminoplast resin (meth) acrylate oligomer modified with an aminoplast resin having many reactive groups in a small molecule, or a novolak epoxy resin, bisphenol epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc. There are oligomers having a cationic polymerizable functional group.

When an ultraviolet curable resin is used as the ionizing radiation curable resin, it is desirable to add about 0.1 to 5 parts by mass of the photopolymerization initiator with respect to 100 parts by mass of the resin. The initiator for photopolymerization can be appropriately selected from those conventionally used and is not particularly limited. For example, for a polymerizable monomer or polymerizable oligomer having a radically polymerizable unsaturated group in the molecule. 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-propane-1 - 4- (2-hydroxyethoxy) phenyl-2 (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2 -Tertiary butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal It is done.
Examples of the polymerizable oligomer having a cationic polymerizable functional group in the molecule include aromatic sulfonium salts, aromatic diazonium salts, aromatic iodonium salts, metallocene compounds, and benzoin sulfonic acid esters.
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 as the ionizing radiation curable resin. This is because the electron beam curable resin 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.

  Examples of the thermoplastic resin used in the present invention include (meth) acrylic resins such as (meth) acrylic acid esters, polyvinyl acetals (butyral resin) such as polyvinyl butyral, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and vinyl chloride resins. , Urethane resins, polyolefins such as polyethylene and polypropylene, styrene resins such as polystyrene and α-methylstyrene, acetal resins such as polyamide, polycarbonate and polyoxymethylene, fluorine resins such as ethylene-4 fluoroethylene copolymer, polyimide , Polylactic acid, polyvinyl acetal resin, liquid crystalline polyester resin, and the like. These may be used singly or in combination of two or more. When combining 2 or more types, the copolymer of the monomer which comprises these resin may be sufficient, and each resin may be mixed and used.

Among the above thermoplastic resins, those having a (meth) acrylic resin as a main component are preferred in the present invention, and in particular, those obtained by polymerizing a monomer containing at least a (meth) acrylic acid ester as a monomer component. preferable.
More specifically, a homopolymer of (meth) acrylic acid ester, a copolymer of two or more different (meth) acrylic acid ester monomers, or a copolymer of (meth) acrylic acid ester and other monomers Is preferred.

  Here, as (meth) acrylic acid ester, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, cyclohexyl methacrylate, normal butyl methacrylate, isobutyl methacrylate Secondary butyl methacrylate, tertiary butyl methacrylate, isobornyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, and the like. Among these, methyl methacrylate is most preferable. That is, it is one of the preferable embodiments to use a homopolymer of methyl methacrylate as the thermoplastic resin of the present invention.

  Next, examples of the copolymer of two or more different (meth) acrylic acid ester monomers include a copolymer of two or more (meth) acrylic acid esters selected from those exemplified above. Also in the polymer, those having methyl methacrylate as a main component are preferable. That is, a copolymer of methyl methacrylate and other (meth) acrylic acid ester monomers is preferable, and other (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, propyl acrylate, ethyl methacrylate, Propyl methacrylate, normal butyl methacrylate, isobutyl methacrylate, secondary butyl methacrylate, tertiary butyl methacrylate, isobornyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl methacrylate, etc. Of these, methyl acrylate is particularly preferred from the viewpoint of effects. In addition, these copolymers may be random copolymers or block copolymers.

Moreover, in the copolymer of methyl methacrylate and other (meth) acrylic acid ester monomers, the structural unit derived from other (meth) acrylic acid ester monomers with respect to 100 moles of the structural unit derived from methyl methacrylate. Is preferably in the range of 0.1 to 200 mol. When the structural unit derived from another (meth) acrylic acid ester monomer is within the above range with respect to 100 moles of the structural unit derived from methyl methacrylate, the wear resistance, scratch resistance and solvent resistance are improved. .
In the copolymer of methyl methacrylate and methyl acrylate, which is a particularly preferred embodiment, the structural unit derived from methyl acrylate is 0.1 to 10 moles relative to 100 moles of the structural unit derived from methyl methacrylate. A range is preferable. When the structural unit derived from methyl acrylate is within the above range with respect to 100 mol of the structural unit derived from methyl methacrylate, the surface wear resistance, scratch resistance, and solvent resistance after the surface protective layer is formed. Especially improved. From the above points, the structural unit derived from methyl acrylate is more preferably in the range of 1 to 9 moles relative to 100 moles of the structural unit derived from methyl methacrylate.

Next, the copolymer of (meth) acrylate and other monomer is not particularly limited as long as the other monomer can be copolymerized with (meth) acrylate, but in the present invention, ( (Meth) acrylic acid, styrene, (anhydrous) maleic acid, fumaric acid, divinylbenzene, vinylbiphenyl, vinylnaphthalene, diphenylethylene, vinyl acetate, vinyl chloride, vinyl fluoride, vinyl alcohol, acrylonitrile, acrylamide, butadiene, isoprene, isobutene , Cycloaliphatic olefin monomers such as 1-butene, 2-butene, N-vinyl-2-pyrrolidone, dicyclopentadiene, ethylidene norbornene, norbornene, maleimides such as vinylcaprolactam, citraconic anhydride, N-phenylmaleimide , Vinyl ether And the like, particularly styrene and (anhydrous) maleic acid is preferable as a copolymerization component. That is, a binary copolymer of (meth) acrylic acid ester and styrene or (anhydrous) maleic acid, or a terpolymer of (meth) acrylic acid ester, styrene and (anhydrous) maleic acid is preferable.
In addition, the copolymer of (meth) acrylic acid ester and another monomer may be a random copolymer or a block copolymer.

  In the copolymer of the (meth) acrylic acid ester and styrene and / or (anhydrous) maleic acid, styrene and / or (/) with respect to 100 mol of the structural unit derived from the (meth) acrylic acid ester. The structural unit derived from maleic anhydride) is preferably in the range of 0.1 to 200 mol. When the structural unit derived from styrene and / or (anhydrous) maleic acid is within the above range with respect to 100 moles of the structural unit derived from (meth) acrylic acid ester, the wear resistance, scratch resistance, solvent resistance Improves.

The thermoplastic resin has a weight average molecular weight in the range of 90,000 to 120,000. When the weight average molecular weight is within this range, the formability after crosslinking and curing to form the surface protective layer, the surface wear resistance, and the scratch resistance can all be obtained at a high level.
Here, the weight average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography (GPC). The solvent used here can be appropriately selected from those usually used, and examples thereof include tetrahydrofuran (THF) and N-methyl-2-pyrrolidinone (NMP).

  The polydispersity (weight average molecular weight Mw / number average molecular weight Mn) of the thermoplastic resin is preferably in the range of 1.1 to 3.0. If the polydispersity is within this range, it is possible to obtain a high level of moldability, surface abrasion resistance, and scratch resistance after crosslinking and curing to form a surface protective layer. From the above points, the polydispersity of the (meth) acrylic resin is preferably in the range of 1.5 to 2.5.

  As for the resin composition which comprises the transparent resin layer of the decorating sheet | seat of this invention, the mass ratio of ionizing radiation-curable resin and a thermoplastic resin is the range of 75: 25-25: 75. Within this range, the balance between the formability after crosslinking and curing to form the transparent resin layer, the wear resistance of the surface, and the scratch resistance becomes good. From the above points, the mass ratio between the ionizing radiation curable resin and the thermoplastic resin is more preferably in the range of 60:40 to 25:75.

The surface protective layer in the present invention is obtained by curing a curable resin composition. The curable resin is not particularly limited, and examples thereof include a thermosetting resin and an ionizing radiation curable resin.
Thermosetting resins include epoxy resin, phenol resin, urea resin, unsaturated polyester resin, melamine resin, alkyd resin, polyimide resin, silicone resin, hydroxyl functional acrylic resin, carboxyl functional acrylic resin, amide functional copolymer Examples include coalescence and urethane resin.
The mode of crosslinking and curing of these resins is not particularly limited, and includes the following modes. Epoxy resin is reaction with amine, acid catalyst, carboxylic acid, acid anhydride, hydroxyl group, dicyandiamide or ketimine, phenol resin is reaction between base catalyst and excess aldehyde, urea resin is polycondensation under alkaline or acidic conditions Reaction, unsaturated polyester resin is a co-condensation reaction of maleic anhydride and diol, melamine resin is a heat polycondensation reaction of methylol melamine, alkyd resin is a reaction by air oxidation of unsaturated groups introduced into side chains, The polyimide resin is a reaction in the presence of an acid or a weak alkali catalyst, or a reaction with an isocyanate compound (in the case of a two-component type), the silicone resin is a condensation reaction in the presence of an acid catalyst of a silanol group, hydroxyl group functionality Acrylic resin is a reaction between hydroxyl group and amino resin of its own (in the case of 1-pack type), carboxyl functional acrylic resin is Reactions with carboxylic acids such as acrylic acid or methacrylic acid and epoxy compounds, amide functional copolymers react with hydroxyl groups or self-condensation reactions, urethane resins include hydroxyl group-containing polyester resins, polyether resins, acrylic resins, etc. Crosslinking and curing are promoted by reaction of the resin with an isocyanate compound or a modified product thereof. A crosslinking agent or a curing agent utilizing these reactions is usually used.
As the ionizing radiation curable resin, the same ones as described above can be used. In the present invention, an ionizing radiation curable resin is more preferable from the viewpoint of curability, and an electron beam curable resin is particularly preferable because it is not necessary to use a solvent.

In particular, the curable resin composition is preferably a resin composition containing an ionizing radiation curable resin and a thermoplastic resin in a ratio (mass ratio) of 75:25 to 25:75 and containing a matting agent. . As the thermoplastic resin used here, those similar to those described above are preferably used, and in the same manner as described above, the polystyrene-reduced weight average molecular weight measured by gel permeation chromatography (GPC) of the thermoplastic resin. Is preferably in the range of 90,000 to 120,000.
In addition, when the ionizing radiation curable resin and the thermoplastic resin are in the range of 75:25 to 25:75, the moldability after forming the surface protective layer by crosslinking and curing, the surface wear resistance, and the scratch resistance. Balance becomes good. From the above points, the mass ratio between the ionizing radiation curable resin and the thermoplastic resin is more preferably in the range of 60:40 to 25:75.

The resin composition for forming the surface protective layer in the present invention preferably has a storage elastic modulus at 140 ° C. in the range of 1 × 10 ^{5 to} 1.2 × 10 ⁸ Pa. If the storage elastic modulus is within this range, a well-decorated decorative sheet can be obtained that satisfies both the formability after forming the surface protective layer, the surface abrasion resistance, and the scratch resistance at a high level. It is done. In particular, the storage elastic modulus at 140 ° C. is preferably in the range of 7.7 × 10 ^{5 to} 1.2 × 10 ⁸ Pa. When the storage elastic modulus is 1.2 × 10 ⁸ Pa or less, the surface protective layer is not cracked during vacuum forming, and can be molded. In the case of a cross-linked resin, the higher the storage elastic modulus in the rubber state, the lower the average molecular weight between cross-linking points, that is, the higher the cross-linking density, so that the surface wear resistance, scratch resistance, solvent resistance, Contamination resistance is improved. Therefore, when the storage elastic modulus is within this range, a decorative sheet that can satisfy the moldability after forming the surface protective layer and the wear resistance and scratch resistance of the surface at a higher level can be obtained. From the above viewpoint, the storage elastic modulus is particularly preferably 1.0 × 10 ^{6 to} 1.0 × 10 ⁷ Pa.
The storage elastic modulus was measured in accordance with JIS K7244-1 and 7244-4, and a sheet having a width of 10 mm and a thickness of 15 μm formed by crosslinking and curing the resin composition constituting the surface protective layer was 10 mm in distance between clamps. Measured at a start temperature of 30 ° C., an end temperature of 180 ° C., a heating rate of 5 ° C./min, and a measurement frequency of 1 Hz.

  Moreover, it is preferable that the resin composition which comprises the surface protective layer in this invention contains a matting agent. The matting agent is not particularly limited as long as it is usually used for decorative sheets. Organic fillers such as silica, calcium carbonate, barium sulfate, alumina, and glass balloons, crosslinked acrylic beads, urethane beads, and polyethylene are used. And fine powders such as fillers. Among these, silica is preferable from the viewpoints of design properties and coating stability.

About the average particle diameter of the said matting agent, the range of 0.1-10 micrometers is preferable. When the thickness is 0.1 μm or more, a sufficient matting effect is observed, and when the thickness is 10 μm or less, the matting agent can be uniformly dispersed to form a beautiful matte surface. From the above viewpoint, the average particle size of the matting agent is more preferably in the range of 0.2 to 5 μm, particularly preferably in the range of 1 to 4 μm.
Moreover, as content of a matting agent, it is preferable that it is the range of 1-50 mass% in a resin composition, and the range of 5-20 mass% is further more preferable.

Moreover, various additives can be mix | blended with the resin composition which comprises the surface protective layer in this invention according to the desired physical property of the cured resin layer obtained. 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, and as the inorganic ultraviolet absorber, titanium dioxide, cerium oxide, zinc oxide or the like having an average particle diameter 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 (formability and abrasion resistance) as a surface protective layer of the polymer of this invention is not impaired.

Examples of the wear resistance improver include, for inorganic substances, spherical particles such as α-alumina, silica, kaolinite, iron oxide, diamond, and silicon carbide. Examples of the particle shape include a sphere, an ellipsoid, a polyhedron, a scale shape, and the like. Although there is no particular limitation, a spherical shape is preferable. Organic materials include synthetic resin beads such as cross-linked acrylic resin and polycarbonate resin. The particle size is usually about 30 to 200% of the film thickness. Among these, spherical α-alumina is particularly preferable because it has high hardness and a large effect on improving wear resistance, and it is relatively easy to obtain spherical particles.
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.

Next, the configuration of the decorative sheet of the present invention will be described in detail with reference to FIG.
FIG. 1 is a schematic view showing a cross section of a decorative sheet 10 of the present invention when used for insert molding. In the example shown in FIG. 1, the pattern layer 12, the masking layer 13, and the adhesive layer 14 are provided on the base material 11, and the surface protective layer 15 and the transparent resin layer 16 are provided on the opposite side of the pattern layer 12 of the base material 11. It is what has. Here, the surface protective layer 15 is formed by crosslinking and curing the above-described resin composition for forming a surface protective layer. A primer layer may be provided between the base material 11 and the surface protective layer 15.

The substrate 11 is selected in consideration of suitability for vacuum forming, and typically a resin sheet made of a thermoplastic resin is used. As the thermoplastic resin, acrylic resins, polyolefin resins such as polypropylene and polyethylene, polycarbonate resins, acrylonitrile-butadiene-styrene resins (hereinafter referred to as “ABS resins”), vinyl chloride resins and the like are generally used. . Moreover, the base material 11 can be used as a single layer sheet of these resins or a multilayer sheet of the same kind or different kind of resin.
Although the thickness of a base material is selected according to a use, it is about 0.03-1.0 mm normally, and when considering the cost etc., about 0.03-0.2 mm is common.

These base materials can be subjected to physical or chemical surface treatment such as an oxidation method or an unevenness method on one side or both sides, if desired, in order to improve the adhesion to the layer provided thereon.
Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method, and examples of the unevenness method include a sand blast method and a solvent treatment method. These surface treatments are appropriately selected depending on the type of substrate, but generally, a corona discharge treatment method is preferably used from the viewpoints of effects and operability.
Further, the substrate may be subjected to a treatment such as forming a primer layer, or a coating for adjusting the color or a pattern from a design viewpoint may be formed in advance.

  The pattern layer 12 shown in FIG. 1 gives decorativeness to the resin molded product, and is formed by printing various patterns using ink and a printing machine. As patterns, there are stone patterns imitating the surface of rocks, such as wood grain patterns, marble patterns (for example, travertine marble patterns), fabric patterns imitating cloth or cloth-like patterns, tiled patterns, brickwork patterns, etc. There are also patterns such as marquetry and patchwork that combine these. These patterns are formed by multicolor printing with the usual yellow, red, blue and black process colors, as well as by multicolor printing with special colors prepared by preparing the individual color plates that make up the pattern. Is done.

As the pattern ink used for the pattern layer 12, a binder and 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 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, and polyesters. Arbitrary resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, cellulose acetate resins and the like may be used alone or in combination of two or more.
Colorants include carbon black (black), iron black, titanium white, antimony white, yellow lead, titanium yellow, petal, cadmium red, ultramarine, cobalt blue and other inorganic pigments, quinacridone red, isoindolinone yellow, phthalocyanine Organic pigments or dyes such as blue, metallic pigments composed of scaly foil pieces such as aluminum and brass, pearlescent pigments composed of scaly foil pieces such as titanium dioxide-coated mica and basic lead carbonate, and the like are used.

  The hiding layer 13 is a layer provided as desired, and is provided for the purpose of preventing the pattern color of the decorative sheet from being affected by changes and variations in the color of the backer film surface. Usually, it is often formed with an opaque color, and a so-called solid printing layer having a thickness of about 1 to 20 μm is preferably used.

  Since the decorative sheet 10 improves the adhesion with the injection resin, an adhesive layer 14 can be provided if desired. A thermoplastic resin or a curable resin is used for the adhesive layer 14 in accordance with the injection resin. Examples of the thermoplastic resin 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 a urethane resin and an epoxy resin.

The primer layer provided as desired between the base material 11 and the surface protective layer 15 has an effect of making it difficult for fine cracks and whitening to occur in the stretched portion of the surface protective layer 15.
In the decorative sheet of the present invention, the elongation at break at 120 ° C. measured under the following measurement conditions for the primer layer is preferably 200% or more, and more preferably 300% or more. When the elongation at break is 200% or more, fine cracks and whitening hardly occur in the stretched portion of the surface protective layer during vacuum forming.
(Measurement conditions for measuring elongation at break)
According to JIS K 7127: 1999, the primer composition constituting the primer layer was crosslinked and cured (heated at 50 ° C. for 72 hours) to form a film of 25 mm width × length (distance between chucks) 50 mm × thickness 40 ± 10 μm. After leaving the sample in an oven at 120 ° C. and leaving it for 120 seconds, the elongation at break is measured at a tensile rate of 50 mm / min.

  Moreover, it is preferable that the thickness of a primer layer is 0.1 micrometer or more. When it is 0.1 μm or more, the surface protective layer has an effect of preventing cracking, breaking, whitening, and the like. On the other hand, if the thickness of the primer layer is 10 μm or less, when the primer layer is applied, the coating film is stable in drying and curing, so that the moldability does not fluctuate. From this viewpoint, the thickness of the primer layer is preferably 1 to 10 μm.

The primer composition constituting the primer layer according to the present invention includes (meth) acrylic resin, urethane resin, (meth) acrylic / urethane copolymer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, butyral resin, chlorine Polypropylene, chlorinated polyethylene, etc. are 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 made of a homopolymer or a copolymer containing a (meth) acrylic acid ester such as the above is preferably used.
Here, (meth) acryl means acryl or methacryl.

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.

  As a method for forming the primer layer, it can be formed directly by a coating method, or a transfer method can be used. When the primer layer 5 is formed by the direct coating method, gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating, kiss coating, wheeler coating, dip coating, silk screen solid coating, wire bar A coat, a flow coat, a comma coat, a pouring coat, a brush coat, a spray coat, etc. can be used. The transfer coating method is a method in which a coating film of a primer layer is once formed on a thin sheet (film substrate) and then coated on the surface of the substrate, and the coating film of the coating composition is coated on the substrate. In addition, there are a laminating method for adhering to a three-dimensional object, and a transfer method in which only a support sheet is peeled after bonding a transfer sheet once formed with a coating film and, if necessary, an adhesive layer on a releasable support sheet.

The formation of the surface protective layer 15 can be obtained by preparing a coating liquid containing the above-mentioned resin composition for forming the surface protective layer, 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 applied to the surface of the substrate 11 so that the thickness after curing is 1-1000 μm, such as gravure coating, bar coating, roll coating, reverse roll coating, comma coating, etc. The known method, preferably gravure coating, is applied to form an uncured resin layer.

The decorative sheet of the present invention is characterized by having a transparent resin layer 16 partially provided on the surface protective layer 15. This transparent resin layer 16 imparts a gloss difference to the decorative sheet 10 due to a gloss difference with the surface protective layer 15, and in particular, provides a texture by synchronizing with the above-described pattern layer 12. Specifically, for example, when the picture layer 12 is a wood grain pattern, the wood grain pattern can have a real feeling by synchronizing the conduit portion and the portion where the transparent resin layer 16 is removed.
In order to express a gloss difference between the transparent resin layer 16 and the surface protective layer 15, it is preferable to add a matting agent to the surface protective layer 15 as described above. Although the matting agent may be blended in the transparent resin layer 16, the surface protective layer 15 is relatively in a low-gloss state by controlling the blending amount, type, particle size, etc. of the matting agent in both layers. (Matte) It is preferable that the transparent resin layer 16 is in a highly glossy state (gross) to develop a gloss difference between the two layers.

  The transparent resin layer 16 is obtained by crosslinking and curing a resin composition containing an ionizing radiation curable resin, and the same ionizing radiation curable resin as that described in the description of the surface protective layer 15 may be used. In particular, an electron beam curable resin is preferable.

In the present invention, the uncured resin layer (surface protective layer 15 and transparent resin layer 16) 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, since the transmission capability increases as the acceleration voltage is higher, when a base material that deteriorates due to an electron beam is used as the base material 11, the transmission depth of the electron beam and the thickness of the resin layer are By selecting an accelerating voltage so as to be substantially equal, it is possible to suppress irradiation of an extra electron beam to the base material 11 and to minimize deterioration of the base material due to the excess electron beam. .
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, a so-called hard coat function, anti-fogging coat function, and anti-fouling coat having high hardness and scratch resistance. 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 the present invention, the thickness of the surface protective layer 15 after curing is 1 to 1000 μm. If the thickness of the surface protective layer 15 after curing is less than 1 μm, sufficient physical properties as a protective layer such as scratch resistance and weather resistance cannot be obtained. In particular, when considering vehicle exterior parts, design properties such as transparency and a feeling of painting and wear resistance are required. Therefore, it is necessary to further increase the thickness of the surface protective layer 15. Therefore, the thickness of the surface protective layer 15 after curing is preferably 20 μm or more. On the other hand, if the thickness of the surface protective layer 15 after curing exceeds 1000 μm, it may be difficult to uniformly apply ionizing radiation, and curing may be insufficient. Moreover, even if it hardens | cures, a moldability deteriorates and also becomes economically disadvantageous.
Since the decorative sheet of the present invention can provide a sufficiently high formability even when the thickness of the surface protective layer 15 is made thicker than the conventional one, it is a member that requires a particularly high film thickness for the surface protective layer. Useful as a decorative sheet.
Moreover, by setting the thickness of the surface protective layer 15 after curing to less than 1 to 20 μm, the moldability is improved, and high followability to a complicated three-dimensional shape such as an automobile interior use can be obtained. Therefore, in the decorative sheet of the present invention, even if a hard ionizing radiation curable resin is blended, excellent moldability can be expressed, and the coating film can be hardened without impairing the moldability. Excellent properties such as scratch resistance and stain resistance required for processing and practical use can be imparted.

In addition, the decorative sheet of the present invention preferably has a tensile elongation of 50% or more in a tensile test based on JIS K 7127. The higher the tensile elongation is, the better the moldability is. However, if the tensile elongation is 50% or more, the surface protective layer is not cracked during vacuum forming with a commonly used vacuum forming die. The tensile elongation is more preferably 150% or more. When the tensile elongation is 150% or more, it follows a complicated shape or a shape with large deformation, and no cracks are generated in the surface protective layer.
The measurement conditions were a test piece having a width of 25 mm and a length of 120 mm, a tensile speed of 1000 mm / min, a distance between chucks of 80 mm, a distance between marked lines of 50 mm, and a temperature of 160 ° C. The surface protective layer was cracked. The tensile elongation at the time of entering is evaluated.

The decorative sheet of the present invention can be used for various injection molding methods such as insert molding method, injection molding simultaneous decoration method, blow molding method, gas injection molding method, etc. Preferably used.
In the insert molding method, in the vacuum forming process, the decorative sheet of the present invention is vacuum formed into a surface shape of the molded product in advance (off-line pre-molding) with a vacuum forming die, and then the excess portion is trimmed as necessary to form a molded sheet. Get. This molded sheet is inserted into an injection mold, the injection mold is clamped, the resin in a fluid state is injected into the mold and solidified, and the decorative sheet is integrated on the outer surface of the resin molding simultaneously with the injection molding. To produce decorative resin molded products.

  As the injection resin, a resin corresponding to the application is used, and a thermoplastic resin such as a polyolefin resin such as polyethylene or polypropylene, an ABS resin, a styrene resin, a polycarbonate resin, an acrylic resin, or a vinyl chloride resin is representative. In addition, thermosetting resins such as urethane resins and epoxy resins can be used depending on applications.

Next, in the simultaneous injection molding decoration method, the decorative sheet of the present invention is placed in a female mold that is also used as a vacuum forming mold provided with a suction hole for injection molding, and pre-molding (in-line pre-molding) with this female mold ), The injection mold is clamped, the resin in a fluid state is injected into the mold, solidified, and the decorative sheet is integrated with the outer surface of the resin molding simultaneously with the injection molding, Manufactures decorative resin molded products.
In the injection molding simultaneous decorating method, the decorative sheet receives the thermal pressure from the injection resin, so if the decorative sheet is close to the flat plate and the aperture of the decorative sheet is small, the decorative sheet may or may not be preheated. .
In addition, as injection resin used here, the thing similar to what was demonstrated by the insert molding method can be used.

The decorated resin molded body produced as described above does not crack in the surface protective layer during the molding process, and its surface has high wear resistance and scratch resistance. Moreover, solvent resistance and chemical resistance are high with respect to the acrylic film conventionally used as a surface protective layer. Furthermore, in the production method of the present invention, the surface protective layer is completely cured at the production stage of the decorative sheet, and therefore a step of crosslinking and curing the surface protective layer after producing the decorative resin molded body is unnecessary.
The decorative resin molded body of the present invention is, for example, an interior material or exterior material of a vehicle such as an automobile, a construction member such as a skirting board or a fringe, a fitting such as a window frame or a door frame, a building such as a wall, a floor, or a ceiling. It is suitable for applications such as interior materials for products, housings and containers for household electrical appliances such as television receivers and air conditioners.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
Evaluation method (1) Formability (vacuum forming)
About the decorative sheet obtained by each Example and the comparative example, it vacuum-formed by the method shown below, and evaluated by the external appearance after shaping | molding. The evaluation criteria are as follows.
◎: No abnormal appearance ○: Minor gloss change or crack in part of 3D shape part or 200% stretched part, but no problem in practical use △; Minor part of 3D shape part or 200% stretched part Gloss change or crack generation ×: Significant gloss change or crack generation in the entire stretched part <Vacuum forming>
The decorative sheet is heated to 160 ° C. with an infrared heater and softened. Next, vacuum molding is performed using a mold having the same shape as the female mold for injection molding (maximum draw ratio is 200 times), and the inner mold is molded. The decorative sheet is released from the mold, and unnecessary parts are trimmed to obtain a molded product.

(2) Formability (simultaneous injection molding)
The decorative sheet obtained in each example and comparative example was subjected to simultaneous injection molding by the method shown below, and the appearance after molding was evaluated. The evaluation criteria are the same as the evaluation criteria in the vacuum forming.
<Injection molding simultaneous decoration>
The decorative sheet was placed in a movable mold, the decorative sheet was heated to 130 ° C. with an infrared radiation surface heater and softened, and then preliminarily molded by vacuum molding with an injection mold. Thereafter, both the male and female molds were clamped, and then the heat-resistant ABS resin was injected from the male gate, and the decorative sheet was laminated and integrated on the surface simultaneously with the molding of the injection molded product, thereby molding a decorative molded product. The injection molding conditions are: injection resin temperature 230 ° C., hot runner manifold portion temperature 240 ° C., gate portion temperature 235 ° C., mold is female die 45 ° C., male die 50 ° C., injection time 5 seconds, cooling time 20 Went in seconds. After mold opening, the decorative molded product was taken out of the mold to obtain a simultaneous injection molded decorative product.

(3) Scratch resistance About the decorative sheet manufactured by each Example and the comparative example, it tested based on JISL0849 [Abrasion testing machine type II (Gakushin type)], and evaluated with the following references | standards. The apparatus used for the test was a “Gakushin Abrasion Tester” manufactured by Tester Sangyo Co., Ltd., and evaluated using test pieces after 50 reciprocations at 500 g load using Kanakin No. 3 as a white cotton cloth for friction. The evaluation criteria are as follows.
◎: No scratch ○: No significant scratch on appearance △: Scratch or gloss change occurs on the surface of 1/4 to 1/2 of the test surface ×: Scratch or gloss change is 1/2 of the test surface Above

(4) Tensile elongation On the back surface of a transparent acrylic resin film having a thickness of 75 μm, a woodgrain pattern layer was formed by gravure printing. Next, the thickness after curing of the electron beam curable resin composition used for the production of the surface protective layer of the decorative sheet produced in each of the examples and comparative examples is 5 μm. Coated so that. This uncured resin layer is 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, and then a urethane film having a thickness of 10 μm is applied to the pattern layer of the sheet. Adhesive was applied, and a decorative sheet was obtained by laminating with a masked colored ABS resin sheet having a film thickness of 400 μm as a backer film. A test piece having a width of 25 mm and a length of 120 mm was cut out as a test piece, a tensile test was performed under the conditions of a tensile speed of 1000 mm / min, a chuck distance of 80 mm, a gauge line distance of 50 mm, and a temperature of 160 ° C., and the elongation was measured to 200%. . Evaluation was made based on the tensile elongation (%) at which cracks occurred in the cured film, and those having no cracks up to an elongation of 200% were expressed as> 200.

(5) Measurement of molecular weight A high-speed GPC apparatus manufactured by Tosoh Corporation was used. The column used was TSKgel αM (trade name) manufactured by Tosoh Corporation, the solvent was N-methyl-2-pyrrolidinone (NMP), and the measurement was performed at a column temperature of 40 ° C. and a flow rate of 0.5 cc / min. The molecular weight and molecular weight distribution in the present invention were converted to polystyrene.

(6) Storage elastic modulus The resin composition for forming a surface protective layer produced in each example and comparative example was applied on a PET film that had not been surface-treated so that the film thickness after crosslinking and curing was about 15 μm. . The 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. The cured film was peeled off from the PET film, and a test piece having a width of 10 mm and a length of 20 mm was cut out. Using this test piece, in accordance with JIS K7244-1 and 7244-4, using a dynamic viscoelasticity measuring apparatus (“RSA II” manufactured by Rheometric Science F.E.), stored at 140 ° C. The elastic modulus was measured. The measurement was performed at a distance between clamps of 10 mm, a start temperature of 30 ° C., an end temperature of 180 ° C., a temperature increase rate of 5 ° C./min, and a measurement frequency of 1 Hz.

(7) Designability The designability of the surface was visually evaluated. The evaluation criteria are as follows.
A: The conduit part was recognized as a concave part, and the texture of the wood was also obtained, and the design was extremely high.
○: The conduit part was recognized as a concave part, and the design was high.
X: The design was flat and inferior in design.

Example 1
To 25 parts by mass of a tetrafunctional urethane acrylate (EB-1, see Table 1), which is an electron beam curable resin (hereinafter referred to as “EB resin”), methyl methacrylate (hereinafter referred to as “MMA”) and methyl acrylate (hereinafter referred to as “MMA”) (Hereinafter referred to as “MA”) having a molar ratio of 100: 5, weight average molecular weight (Mw) 1.0 × 10 ⁵ , number average molecular weight (Mn) 0.60 × 10 ⁵ , polydispersity (Mw / Mn) 75 parts by mass of a 1.67 copolymer (hereinafter referred to as “PMMA-1”, see Table 1) is mixed, and 10 parts by mass of silica having an average particle diameter of 2 μm is blended therein to form a surface protective layer-forming electron. A linear curable resin composition was obtained. The mass ratio of EB resin: PMMA-1 is 25:75.
Next, a 60 μm thick transparent polypropylene film subjected to double-sided corona discharge treatment is used as the base material, and a two-part curable urethane ink is used on the back of the film to form a woodgrain pattern layer by gravure printing did. Next, a two-part curable urethane-based resin having an acrylic / urethane block copolymer as a main component and isocyanate added as a curing agent is applied to the surface where no pattern layer is applied, and a transparent primer layer having a thickness of 2 μm is formed. Formed. On the primer layer, the surface protective layer-forming electron beam curable resin composition was applied such that the thickness after curing was 3 μm. Next, using the same EB resin as that used for forming the surface protective layer, the gravure so that the conduit portion of the wood grain pattern of the pattern layer is not applied and the thickness after curing is 1 μm. Coating was performed by printing to obtain a transparent resin layer (uncured).
This uncured resin layer (surface protective layer and transparent resin layer) is irradiated with an electron beam with an acceleration voltage of 165 kV and an irradiation dose of 50 kGy (5 Mrad) to cure the electron beam curable resin composition, and then the pattern of the sheet A two-part curable urethane resin adhesive having a film thickness of 10 μm was applied to the layer side, and laminated with a covert colored ABS resin sheet having a film thickness of 400 μm, which was a backer film, to obtain a decorative sheet.
The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Examples 2-4
A decorative sheet was obtained in the same manner as in Example 1 except that the mass ratio of the EB resin and PMMA-1 was changed as described in Table 2. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Reference example 1
Instead of PMMA-1, a copolymer of MMA, styrene and maleic anhydride (MMA: styrene: maleic anhydride molar ratio 100: 32: 84, weight average molecular weight (Mw) 0.96 × 10 ⁵ , number Example 2 except that average molecular weight (Mn) 0.46 × 10 ⁵ , polydispersity (Mw / Mn) 2.09, hereinafter referred to as “PMMA-2” (see Table 1)) A decorative sheet was obtained. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Reference example 2
Instead of PMMA-1, a copolymer of MMA, MA, styrene and maleic anhydride (MMA: MA: styrene: maleic anhydride molar ratio 100: 8: 10: 69, weight average molecular weight (Mw) 1. Implemented except using 0 × 10 ⁵ , number average molecular weight (Mn) 0.57 × 10 ⁵ , polydispersity (Mw / Mn) 1.75, hereinafter referred to as “PMMA-3” (see Table 1) A decorative sheet was obtained in the same manner as in Example 2. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Reference examples 3 and 4
Instead of PMMA-1, MMA homopolymer, weight average molecular weight (Mw) 1.1 × 10 ⁵ , number average molecular weight (Mn) 0.64 × 10 ⁵ , polydispersity (Mw / Mn) A decorative sheet was obtained in the same manner as Example 2 or Example 1 except that 1.72 and hereinafter referred to as “PMMA-4” (see Table 1). The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Examples 9-12
A decorative sheet was obtained in the same manner as in Example 2 except that the film thickness of the surface protective layer was changed as described in Table 2. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Examples 13-18
A decorative sheet was obtained in the same manner as in Example 1 except that the film thickness of the surface protective layer was changed as described in Table 2. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Examples 19 and 20
A decorative sheet was obtained in the same manner as in Example 2 except that PMMA-5 and PMMA-6 shown in Table 1 were used instead of PMMA-1 (see Table 1). The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Examples 21 and 22
Implemented except that bifunctional urethane acrylate (EB-2, see Table 1) was used instead of EB-1 as the EB resin, and the mass ratio of EB resin and PMMA-1 was changed as shown in Table 2. A decorative sheet was obtained in the same manner as in Example 1. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Example 23
A decorative sheet was obtained in the same manner as in Example 2 except that trifunctional urethane acrylate (EB-3, see Table 1) was used instead of EB-1. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Example 24
In Example 2, a decorative sheet was obtained in the same manner as in Example 2 except that the transparent resin layer-forming electron beam curable resin composition further contained 3 parts by mass of silica having an average particle diameter of 2 μm. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Comparative Example 1
In Example 1, a decorative sheet was obtained in the same manner as in Example 1 except that the EB resin was not used. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Comparative Examples 2 and 3
A decorative sheet was obtained in the same manner as in Example 1 except that the mass ratio of the EB resin and PMMA-1 was changed as described in Table 2. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Comparative Example 4
In Example 1, a decorative sheet was obtained in the same manner as in Example 1 except that PMMA was not used. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 3.

Comparative Example 5
A decorative sheet was obtained in the same manner as in Example 1 except that bifunctional urethane acrylate was used as the EB resin and PMMA was not used. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 3.

Comparative Examples 6 and 7
A decorative sheet was obtained in the same manner as in Example 2 except that the film thickness of the surface protective layer was changed as described in Table 3. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 3.

Comparative Examples 8-10
A decorative sheet was obtained in the same manner as in Example 2 except that PMMA-7, PMMA-8 and PMMA-9 shown in Table 1 were used instead of PMMA-1 (see Table 1). The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

Comparative Example 11
A decorative sheet was obtained in the same manner as in Example 1 except that bifunctional urethane acrylate (EB-4, see Table 1) was used instead of EB-1 and PMMA was not used. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 2.

The decorative sheet in which the surface protective layer is formed using the resin composition for forming the surface protective layer of the present invention is in contact with the mold from a heating temperature of about 160 ° C. in a normal insert molding method or simultaneous injection molding method. Cracks and cracks do not occur even under conditions of rapid temperature drop, rapid stretching speed and high degree of stretching to the temperature of the hour. In addition, the design was high, and the texture was particularly imparted to the wood grain pattern.
Furthermore, it was confirmed that the moldability of the decorative resin molded product thus produced was excellent in moldability and high abrasion resistance and scratch resistance.
In particular, the decorative sheets of Examples 9 and 10 have high moldability, and the molded product produced using the decorative sheet has high scratch resistance, high transparency, and high gloss. I had it.

  The surface of the decorative sheet of the present invention has high wear resistance and scratch resistance, and has good moldability and is free from cracks. Therefore, the decorative resin molded body manufactured using the decorative sheet of the present invention does not crack in the surface protective layer during the molding process, and the surface has high wear resistance and scratch resistance. Moreover, according to the manufacturing method of this invention, since a surface protective layer is fully hardened in the manufacture stage of a decorating sheet, the process of bridge | crosslinking and hardening a surface protective layer after manufacturing a decorating resin molding is unnecessary. Furthermore, it is a decorative sheet having a high design property, such as being able to express a gloss difference in synchronism with the pattern layer and imparting a texture.

It is a schematic diagram which shows the cross section of the decorating sheet of this invention.

Explanation of symbols

10. Decorative sheet Base material 12. Pattern layer 13. Concealment layer 14. Adhesive layer 15. Surface protective layer 16. Transparent resin layer 20. Backer film

Claims (21)

A decorative sheet having at least a surface protective layer and a transparent resin layer partially provided on the surface protective layer on a substrate, wherein the surface protective layer comprises an ionizing radiation curable resin and a thermoplastic resin at 75:25. A curable resin composition containing a ratio of 25 to 75 (mass ratio) is cured, and the thermoplastic resin used in the surface protective layer is a combination of methyl methacrylate and other (meth) acrylic acid ester monomers. It is a polymer, and the structural unit derived from other (meth) acrylic acid ester monomers is in the range of 0.1 to 200 moles with respect to 100 moles of the structural unit derived from methyl methacrylate in the thermoplastic resin. , said transparent resin layer is an ionizing radiation curable resin and a thermoplastic resin 75: 25-25: This is a resin composition comprising 75 ratio (mass ratio) obtained by crosslinking and curing the heat used in the transparent resin layer Plastic polystyrene-reduced weight average molecular weight measured by the resin of gel permeation chromatography (GPC) is in the range of 90,000 to 120,000, and the decorative sheet thickness of the surface protective layer is 1 to 1000 m. The curable resin composition constituting the surface protective layer is a resin composition containing a matting agent, and the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) of the thermoplastic resin is 9 The decorative sheet according to claim 1, which is in a range of 10,000 to 120,000. The storage elastic modulus in 140 degreeC measured on the following measurement conditions of the resin composition for forming the said surface protective layer is the range of 1 * 10 < ⁵ > -1.2 * 10 < ⁸ > Pa. Decorative sheet.
Storage elastic modulus measurement conditions: In accordance with JIS K7244-1 and 7244-4, a resin composition for forming a surface protective layer was crosslinked and cured to form a sheet having a width of 10 mm and a thickness of 15 μm. Measurement is performed at 10 mm, a start temperature of 30 ° C., an end temperature of 180 ° C., a temperature increase rate of 5 ° C./min, and a measurement frequency of 1 Hz. The thermoplastic resin used for the surface protective layer is a copolymer of methyl methacrylate and methyl acrylate, and is derived from methyl acrylate with respect to 100 mol of the structural unit derived from methyl methacrylate in the thermoplastic resin. The decorating sheet according to any one of claims 1 to 3, wherein the constituent unit is in a range of 0.1 to 10 mol. The decorative sheet according to any one of claims 1 to 4 , wherein the thermoplastic resin used in the transparent resin layer is obtained by polymerizing a monomer containing at least a (meth) acrylic acid ester. The decorative sheet according to any one of claims 1 to 5 , wherein the thermoplastic resin used in the transparent resin layer is a copolymer of two or more different (meth) acrylic acid ester monomers. The decorative sheet according to claim 6 , wherein the thermoplastic resin used in the transparent resin layer is a copolymer of methyl methacrylate and another (meth) acrylic acid ester monomer. The structural unit derived from other (meth) acrylic acid ester monomers is in the range of 0.1 to 200 mol with respect to 100 mol of the structural unit derived from methyl methacrylate in the thermoplastic resin used for the transparent resin layer. The decorative sheet according to claim 7 . The thermoplastic resin used for the transparent resin layer is a copolymer of methyl methacrylate and methyl acrylate, and is derived from methyl acrylate with respect to 100 mol of the structural unit derived from methyl methacrylate in the thermoplastic resin. The decorative sheet according to claim 7 , wherein the constituent unit is in a range of 0.1 to 10 mol. The decorative sheet according to any one of claims 1 to 4 , wherein the thermoplastic resin used in the transparent resin layer is a copolymer of (meth) acrylic acid ester and styrene and / or (anhydrous) maleic acid. The structural unit derived from styrene and / or (anhydrous) maleic acid is 0.1-200 mol with respect to 100 mol of the structural unit derived from the (meth) acrylic acid ester in the thermoplastic resin used for the transparent resin layer. The decorative sheet according to claim 10 , wherein the decorative sheet is in the range. The decorative sheet according to any one of claims 1 to 4 , wherein the thermoplastic resin used in the transparent resin layer is a homopolymer of methyl methacrylate. The decorating sheet according to any one of claims 1 to 12 , wherein the polydispersity of the thermoplastic resin used for the transparent resin layer is in a range of 1.1 to 3.0. The decorative sheet according to any one of claims 1 to 13, wherein the polydispersity of the thermoplastic resin used in the surface protective layer is in the range of 1.1 to 3.0. The decorative sheet according to any one of claims 1 to 14 , wherein a tensile elongation in a tensile test measured under the following measurement conditions based on JIS K 7127 is 50% or more.
Measurement conditions: Using a test piece with a width of 25 mm and a length of 120 mm, tensile elongation until a crack occurs in the surface protective layer under the conditions of a tensile speed of 1000 mm / min, a distance between chucks of 80 mm, a distance between marked lines of 50 mm, and a temperature of 160 ° C. Measure the degree. The decorative sheet according to any one of claims 1 to 15 , wherein the ionizing radiation curable resin is an electron beam curable resin. The decorating sheet according to any one of claims 2 to 16 , wherein the matting agent is silica. The decorative sheet according to claim 17 , wherein the silica has an average particle diameter of 0.1 to 10 μm. A vacuum forming step of forming the decorative sheet according to any one of claims 1 to 18 in a three-dimensional shape in advance by a vacuum forming die, a step of trimming an excess portion to obtain a formed sheet, and the forming sheet as an injection mold A method for producing a decorative resin molded article, which comprises a step of inserting, closing an injection mold, and injecting a resin in a fluid state into the mold to integrate the resin and the molded sheet. After installing the decorating sheet according to any one of claims 1 to 18 so that the base material of the decorating sheet faces the molding surface of the movable mold having a molding surface of a predetermined shape, A process of pre-molding the decorative sheet by heating and softening the decorative sheet, and vacuum-sucking the decorative sheet from the movable mold side to bring the softened decorative sheet into close contact with the molding surface of the movable mold After the movable mold and the fixed mold having the decorative sheet adhered along the molding surface are clamped, the resin molding material in a fluid state is injected and filled into the cavity formed by both molds. The resin molded body is formed by laminating and integrating the formed resin molded body and the decorative sheet, and the movable mold is separated from the fixed mold and the entire decorative sheet is laminated. Decorative resin molded product that sequentially performs the process of taking out the molded product Manufacturing method. A decorative resin molded product produced by the production method according to claim 19 or 20 .

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