JP2009113385A - Decorative sheet, method for producing decorative resin molding, and decorative resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet which is excellent in vacuum forming properties, prevents the occurrence of cracking, breaking, whitening, etc., on the surface, and is good in wear resistance and abrasion resistance of the surface, a method for producing a decorative resin molding using the sheet, and the decorative resin molding produced by the method. <P>SOLUTION: The decorative sheet has at least a primer layer formed on a substrate and a surface protection layer laminated on the primer layer. The elongation at break at 120°C of the primer layer is 200% or above, and the thickness of the primer layer is 0.6 μm or above. The surface protection layer is formed by crosslinking/curing a resin composition containing an ionizing radiation curable resin and a thermoplastic resin in a mass ratio of 75:25-22:78. The weight average molecular weight in terms of polystyrene measured by a gel permeation chromatograph (GPC) of the thermoplastic resin is 90,000-120,000, and the thickness of the surface protection layer is 1-1,000 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a decorative sheet used for molding a decorative molded product, 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 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 conforms to the mold shape by vacuum / pneumatic action or by the pressure of the molten resin, tensile due to shear stress, etc. Since it is extended beyond the minimum necessary amount, there is a problem that the surface protective layer of the curved surface portion of the molded product is cracked.

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 with respect to moldability, and the surface protective layer was hardly cracked, but the surface scratch resistance of the decorative molded product was 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 forming the surface protective layer of the decorative sheet, the surface of the decorative molded product can be scratch-resistant. Although attempts have been made to improve, there has been a problem that cracks occur 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.

  Further, Patent Document 5 proposes that a primer layer having high yield strength and breaking strength is provided between the printing layer and the protective layer. The adhesion of the surface protective layer is greatly improved by this invention. However, improvements from the viewpoint of preventing cracking and whitening of the surface protective layer during vacuum forming are still desired.

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 International Publication WO00 / 03874 Pamphlet

  In view of the above problems, the present invention uses a decorative sheet that is excellent in vacuum formability and does not generate cracks, breakage, whitening, etc. on the surface, and also has good scratch resistance on the surface, and the decorative sheet. It aims at providing the manufacturing method of a decorative resin molded product, and the decorative resin molded product manufactured by this manufacturing method.

  As a result of intensive studies to achieve the above object, the present inventors have obtained a decorative sheet having at least a primer layer and a surface protective layer on a substrate, and the primer layer has specific physical properties and thickness. The surface protective 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 thickness of the surface protective layer is set to a specific thickness. The inventors have found that the above problems can be solved. The present invention has been completed based on such findings.

That is, the present invention
(1) A decorative sheet having at least a primer layer and a surface protective layer laminated on the primer layer on a substrate, the elongation at break measured at 120 ° C. measured under the following measurement conditions of the primer layer Is 200% or more, the thickness of the primer layer is 0.6 μm or more, and the surface protective layer is made of an ionizing radiation curable resin and a thermoplastic resin in a ratio (mass ratio) of 75:25 to 22:78. A resin composition comprising a crosslinked composition, having a polystyrene-reduced weight average molecular weight of 90,000 to 120,000 measured by gel permeation chromatography (GPC) of the thermoplastic resin, and a surface protective layer A decorative sheet having a thickness of 1-1000 μm,
Breaking elongation measurement conditions: Width of 25 mm obtained by forming a primer composition constituting the primer layer (in the case of a curable composition, it is crosslinked and cured by heating at 50 ° C. for 72 hours) in accordance with JIS K 7127: 1999 X Length (distance between chucks) 50 mm x Thickness 40 ± 10 μm Sample was placed in an oven at 120 ° C. and left for 120 seconds, and then the elongation at break was measured at a tensile rate of 50 mm / min.

(2) The heat softening point temperature, the softening start temperature, and the softening completion temperature of the resin composition, the primer composition, and the base material after crosslinking and curing are all higher than the temperature of the resin composition. The decorative sheet according to (1), wherein the temperature is high and the temperature of the base material is higher than the temperature of the primer composition,
(3) The decorative sheet according to (1) or (2), wherein the storage elastic modulus at 140 ° C. measured under the following measurement conditions of the resin composition is in the range of 1 × 10 ^{5 to} 1.2 × 10 ⁸ Pa. ,
Storage elastic modulus measurement conditions: In accordance with JIS K7244-1 and 7244-4, a sheet of 10 mm width and 15 μm thickness formed by crosslinking and curing the resin composition was 10 mm distance between clamps, start temperature 30 ° C., end Measure at a temperature of 180 ° C., a heating rate of 5 ° C./min, and a measurement frequency of 1 Hz.

(4) In the above (1) to (3), the primer composition contains one or more resins selected from (meth) acrylic resins, urethane resins, and (meth) acrylic / urethane copolymer resins. Any decorative sheet,
(5) The decorative sheet according to any one of (1) to (4), wherein the thermoplastic resin is obtained by polymerizing a monomer containing at least a (meth) acrylic acid ester.
(6) The decorative sheet according to (1) to (4), wherein the thermoplastic resin is a copolymer of two or more different (meth) acrylic acid ester monomers,
(7) The decorative sheet according to (6), wherein the thermoplastic resin is a copolymer of methyl methacrylate and another (meth) acrylic acid ester monomer,
(8) The decorative sheet according to any one of (1) to (4), wherein the thermoplastic resin is a copolymer of (meth) acrylic acid ester and styrene and / or (anhydrous) maleic acid,

(9) A vacuum forming step in which the decorative sheet according to any one of the above (1) to (8) is formed into a three-dimensional shape in advance by a vacuum forming die, a step of trimming excess portions to obtain a formed sheet, A method for producing a decorative resin molded article having a step of inserting into an injection mold, closing the injection mold, injecting a fluid resin into the mold and integrating the resin and the molded sheet;
(10) The decorative sheet according to any one of (1) to (8) 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. Then, the decorative sheet is heated and softened, and is vacuum-sucked from the movable mold side so that the softened decorative sheet is brought into close contact with the molding surface of the movable mold to obtain a decorative sheet. Step of pre-molding, after clamping a movable mold having a decorative sheet closely adhered along the molding surface and a fixed mold, a resin molding material in a fluid state is placed in a cavity formed by both molds. By injection, filling and solidifying, the injection molding process of stacking 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 for sequentially performing a step of taking out the molded resin product The method of manufacturing molded products, and (11) there is provided the (9) or (10) decorated resin molded article produced by the method.

  The decorative sheet of the present invention is excellent in vacuum formability and does not generate cracks, breaks, whitening or the like on the surface, and also has good surface scratch resistance.

The decorative sheet of the present invention is a decorative sheet having at least a primer layer and a surface protective layer laminated on the primer layer on a substrate, and measured under the following measurement conditions of the primer layer. The elongation at break at 200 ° C. is 200% or more, the thickness of the primer layer is 0.6 μm or more, and the surface protective layer is made of an ionizing radiation curable resin and a thermoplastic resin in a ratio of 75:25 to 22:78. The resin composition comprising (mass ratio) is crosslinked and cured, and the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) of the thermoplastic resin is in the range of 90,000 to 120,000, And the thickness of this surface protective layer is 1-1000 micrometers, It is characterized by the above-mentioned.
Here, the measurement conditions of the breaking elongation are based on JIS K 7127: 1999, and the primer composition constituting the primer layer (in the case of a curable composition, it is crosslinked and cured by heating at 50 ° C. for 72 hours) is manufactured. A sample with a width of 25 mm × length (distance between chucks) 50 mm × thickness 40 ± 10 μm is placed in an oven at 120 ° C. and left for 120 seconds, and the elongation at break is measured at a tensile rate of 50 mm / min. is there.

The decorative sheet of the present invention requires that the elongation at break at 120 ° C. measured under the above measurement conditions of the primer layer is 200% or more, and is preferably 300% or more. If the elongation at break is less than 200%, even if the base material and the surface protective layer each show sufficient formability and elongation, if the shape followability and behavior at the time of molding are different, there is a problem when the laminated sheet is molded Specifically, the surface protective layer is cracked or whitened.
On the other hand, in the present invention, by using a primer layer having a breaking elongation at 120 ° C. of 200% or more, not only the effect of improving the adhesion between the substrate and the surface protective layer, but also the substrate and the surface protective layer Even if the shape followability and behavior at the time of molding are different, the effect of alleviating the difference in the followability at the time of molding is exerted, and the effect of suitably preventing cracking, whitening and the like of the surface protective layer is exhibited.

  Moreover, the thickness of a primer layer needs to be 0.6 micrometer or more. This is because if the thickness is less than 0.6 μm, it is not possible to enjoy the effect of preventing the surface protective layer from being cracked, broken or whitened. In the present invention, even if the primer layer exceeds 10 μm, the vacuum formability is not hindered. However, if the primer layer is 10 μm or less, when the primer layer is applied, the coating layer is stable in drying and curing, and thus the formability varies. It is preferable without any problems. From this viewpoint, it is preferable that the primer layer has a thickness of 0.6 to 10 μm.

  In the decorative sheet of the present invention, the resin composition constituting the surface protective layer needs to contain an ionizing radiation curable resin and a thermoplastic resin in a ratio (mass ratio) of 75:25 to 22:78. When the ratio is in the range of 75:25 to 22:78 (mass ratio), the balance between the formability after forming the surface protective layer by crosslinking and curing and the scratch resistance of the surface becomes good. From the above points, the mass ratio of the ionizing radiation curable resin to the thermoplastic resin is preferably in the range of 75:25 to 25:75, and particularly preferably in the range of 60:40 to 25:75. Here, the ionizing radiation curable resin has 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. Point to. Specifically, it can be appropriately selected from polymerizable monomers, polymerizable oligomers, or prepolymers conventionally used as ionizing radiation curable resins.

And the weight average molecular weight of the said thermoplastic resin needs to be the range of 90,000-120,000. When the weight average molecular weight is within this range, both the formability after crosslinking and curing to form the surface protective layer and the scratch resistance of the surface can 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. When the polydispersity is within this range, both the moldability after forming the surface protective layer by crosslinking and curing and the scratch resistance of the surface can be obtained at a high level.

In this invention, the thickness after hardening of a surface protective layer needs to be 1-1000 micrometers. If the thickness of the surface protective layer after curing is less than 1 μm, sufficient physical properties as a protective layer such as scratch resistance and weather resistance cannot be obtained. On the other hand, when the thickness of the surface protective layer after curing exceeds 1000 μm, it is 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.
The thickness of the surface protective layer after curing is appropriately determined within the above range depending on the application.For example, when considering vehicle exterior parts, the design and transparency such as a feeling of transparency and a feeling of painting and scratch resistance are required. Since it is required, it is preferable to increase the thickness of the surface protective layer. Specifically, the thickness of the surface protective layer after curing is preferably 20 μm or more. Since the decorative sheet of the present invention can provide sufficiently high formability even if the thickness of the surface protective layer is made thicker than that of the conventional one, it is possible to add a member that requires a particularly high film thickness to the surface protective layer. Useful as a decorative sheet.
Moreover, when using for a motor vehicle interior use etc., it is preferable that the thickness after hardening of a surface protective layer shall be 1-20 micrometers. By setting it as this range, a moldability improves and the high followable | trackability to a complicated three-dimensional shape can be acquired. 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 resin composition after crosslinking and curing of the decorative sheet of the invention, the primer composition (the primer composition after crosslinking and curing when the primer composition is curable), and the heat softening point temperature of the substrate Both the softening start temperature and the softening completion temperature are preferably in such a relationship that the temperature of the primer composition is higher than the temperature of the resin composition and the temperature of the substrate is higher than the temperature of the primer composition. When the temperature of the primer composition is higher than the temperature of the resin composition, the primer does not first soften and melt during heating, and the heating behavior (stretching) of the ionizing radiation curable resin and the base material can be absorbed and relaxed. Therefore, distortion hardly occurs in each layer constituting the decorative sheet, and the moldability becomes more stable. Moreover, when the said temperature of a base material is higher than the said temperature of a primer composition, a primer will become easy to soften at the time of shaping | molding, and it will become difficult to produce a crack and whitening in a surface protective layer.

The crosslinked cured resin composition constituting the surface protective layer according to 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. When the storage elastic modulus is within this range, a well-decorated decorative sheet that can satisfy both the moldability after forming the surface protective layer and the scratch resistance of the surface at a high level is obtained. 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.
Further, 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 scratch resistance, abrasion resistance, solvent resistance, Contamination resistance is improved. Therefore, if the storage elastic modulus is within this range, a decorative sheet that can satisfy the moldability after forming the surface protective layer and the scratch resistance of the surface at a higher level can be obtained. From the above viewpoint, the storage elastic modulus is more preferably in the range of 7.7 × 10 ^{5 to} 1.2 × 10 ⁸ Pa, and preferably 1.0 × 10 ^{6 to} 1.0 × 10 ⁷ Pa. Is particularly preferred.
The storage elastic modulus is measured according to JIS K7244-1 and 7244-4, and the resin composition constituting the surface protective layer is crosslinked and cured (electron beam irradiation conditions: acceleration voltage 165 kV, irradiation dose 50 kGy (5 Mrad)). A sheet having a width of 10 mm and a thickness of 15 μm is measured 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.

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 and the like are preferably used, and among them, one or more resins selected from (meth) acrylic resins, urethane resins and (meth) acrylic-urethane copolymer resins are more preferable.
(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 and / or modified products thereof are used. The acrylic / urethane (polyester urethane) block copolymer resin preferably has an acrylic / urethane ratio (mass ratio) of preferably (9/1) to (1/9), more preferably (8/2) to (2). / 8). Thereby, since it can be used for a various decorating sheet, it is especially preferable as resin used for a primer composition.

  The polymerizable monomer as the ionizing radiation curable resin used for the surface protective layer according to the present invention is typically a (meth) acrylate monomer having a radically polymerizable unsaturated group in the molecule. Multifunctional (meth) acrylates are preferred. Here, “(meth) acrylate” means “acrylate or methacrylate”, and other similar things 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 resin composition constituting the surface protective layer according to the present invention, the monofunctional (meth) acrylate is used together with the polyfunctional (meth) acrylate for the purpose of lowering the viscosity. They can be used in combination as long as they are not impaired. 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 as the ionizing radiation curable resin used in the surface protective layer according to the present invention, an oligomer having a radical polymerizable unsaturated group in the molecule, for example, epoxy (meth) acrylate, urethane (meta ) Acrylate series, polyester (meth) acrylate series, polyether (meth) acrylate series, and the like. 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, benzyl dimethyl ketal, acetophenone dimethyl ketal, etc. 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 an initiator for photopolymerization, so that stable curing characteristics can be obtained.

  As the thermoplastic resin used in the resin composition constituting the surface protective layer according to the present invention, (meth) acrylic resin such as (meth) acrylic acid ester, polyvinyl acetal (butyral resin) such as polyvinyl butyral, polyethylene terephthalate, Polyester resins such as polybutylene terephthalate, 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, ethylene-4 fluorine Fluorine resins such as fluorinated ethylene copolymer, polyimide, polylactic acid, polyvinyl acetal resin, liquid crystalline polyester resin and the like may be mentioned, and these may be used alone 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 those obtained by polymerizing a monomer containing at least a (meth) acrylic acid ester as a monomer component are particularly preferred. .
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 scratch resistance and solvent resistance are improved.
In the copolymer of methyl methacrylate and methyl acrylate, which is a particularly preferred embodiment, the range of 0.1 to 10 moles of structural units derived from methyl acrylate with respect to 100 moles of structural units derived from methyl methacrylate. It is preferable that When the structural unit derived from methyl acrylate is within the above range with respect to 100 moles of the structural unit derived from methyl methacrylate, the scratch resistance and solvent resistance of the surface after forming the surface protective layer are particularly improved. To do. 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 Etc., and 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 mol of the structural unit derived from (meth) acrylic acid ester, the scratch resistance and solvent resistance are also improved. .
The polydispersity of the (meth) acrylic resin is particularly preferably in the range of 1.5 to 2.5.

Various additives can be blended in the resin composition constituting the surface protective layer according to the present invention depending on the desired physical properties of the resulting cured resin layer. Examples of the additive include a weather resistance improver, a scratch 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. Moreover, as an organic type ultraviolet absorber, benzotriazole type, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-) is specifically mentioned. 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. In addition, 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 scratch resistance improver include spherical particles such as α-alumina, silica, kaolinite, iron oxide, diamond, and silicon carbide as inorganic substances. 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 scratch resistance, and it is relatively easy to obtain spherical particles.
Examples of the polymerization inhibitor include hydroquinone, p-benzoquinone, hydroquinone monomethyl ether, pyrogallol, t-butylcatechol, and the like, and 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, it has a picture layer 12 that is optionally provided on the base material 11, a concealing layer 13 that is optionally provided, and an adhesive layer 14 that is optionally provided, and is opposite to the picture layer 12 of the base material 11. The primer layer 15 and the surface protective layer 16 are provided on the side. Here, the surface protective layer 16 is formed by crosslinking and curing the above resin composition.
If desired, for example, in the case of a decorative sheet for insert molding, a backer film 20 is laminated on the adhesive layer 14.

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 a concavo-convex method on one side or both sides, if desired, in order to improve adhesion with a 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 sand blast method and 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 patterns, tiled patterns, brickwork patterns, etc. There are also patterns such as marquetry and patchwork that combine these. These patterns can be formed by multicolor printing with normal yellow, red, blue, and black process colors, and also by multicolor printing with special colors prepared by preparing individual color plates that make up the pattern. Is done.

As the pattern ink used for the pattern layer 12, a binder appropriately mixed with a colorant such as a pigment or a 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, and polyesters. Arbitrary resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, cellulose acetate resins and the like may be used alone or in admixture 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 concealing layer 13 is a layer provided as desired, and is provided for the purpose of preventing the pattern color of the decorative sheet 10 from being affected by changes and variations in the color of the surface of the backer film 20. 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 15 can be formed by a direct coating method, or a transfer method can be used. When the primer layer 15 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 a transfer sheet once formed with a coating film and an adhesive layer on a releasable support sheet is adhered.
Although the crosslinking and curing conditions for forming the primer layer 15 depend on the resin used, it is usually preferable to heat at 40 to 60 ° C. for 24 to 168 hours.

Formation of the surface protective layer 16 can be obtained by preparing a coating liquid containing the above-mentioned 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 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.

In the surface protective layer 16 according to the present invention, the uncured resin layer is cured by irradiating the uncured resin layer thus formed with ionizing radiation such as an electron beam or ultraviolet rays. 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, a high frequency type, etc. 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 addition, the decorative sheet 10 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 the surface protective layer does not crack.
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., and the surface protective layer was cracked. The tensile elongation at the time of entering is evaluated.

The decorative sheet 10 of the present invention can be used for various injection molding methods such as an insert molding method, a simultaneous injection molding method, a blow molding method, and a gas injection molding method, and the insert molding method and the simultaneous injection molding method. Is preferably used.
In the insert molding method, in the vacuum forming step, the decorative sheet 10 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 trimmed as necessary to form. Get a sheet. This molded sheet is inserted into an injection mold, the injection mold is closed and the mold is closed, and the resin in a fluid state is injected into the mold and solidified. At the same time as the injection molding, the decorative sheet is placed on the outer surface of the resin molded product. 10 is integrated and a decorative resin molded product is manufactured.

The injection resin is a resin suitable for the intended use. Polyolefin resins such as polyethylene and polypropylene, acrylonitrile / butadiene / styrene copolymer [ABS] resin, styrene resin, polycarbonate resin, acrylic resin, vinyl chloride resin, etc. Resin is typical. In addition, thermosetting resins such as urethane resins and epoxy resins can be used depending on applications.
Further, as the backer film 20, a resin having good adhesiveness with an injection resin is preferably used, and a polyolefin resin such as polyethylene or polypropylene, an ABS resin, or the like is preferable.

  Next, in the simultaneous injection molding decoration method, the decorative sheet 10 of the present invention is installed so that the base of the decorative sheet faces the molding surface of the movable mold having a molding surface of a predetermined shape. Then, the decorative sheet is heated and softened, and is vacuum-sucked from the movable mold side so that the softened decorative sheet is brought into close contact with the molding surface of the movable mold to obtain a decorative sheet. Step of pre-molding, after clamping a movable mold having a decorative sheet closely adhered along the molding surface and a fixed mold, a resin molding material in a fluid state is placed in a cavity formed by both molds. By injection, filling and solidifying, the injection molding process of stacking 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 The process of taking out the molded resin product is sequentially performed. Method for producing a decorated resin molded article is preferred.

Here, the movable mold is a female mold that is also used as a vacuum mold having a suction hole for injection molding. After the preform (in-line pre-molding) is performed with the female mold, the injection mold is clamped. Then, it is preferable that the resin in a fluid state is injected and filled into a mold and solidified, and the decorative sheet 10 is integrated with the outer surface of the resin molding simultaneously with the injection molding to produce a decorative resin molded product. .
In the injection molding simultaneous decorating method, the decorative sheet 10 receives heat pressure from the injection resin, and therefore, when the decorative sheet 10 is close to a flat plate and the aperture of the decorative sheet 10 is small, the decorative sheet 10 may not be preheated. May be.
In addition, as injection resin used here, the thing similar to what was demonstrated by the insert molding method can be used.

  The decorative resin molded body produced as described above does not cause cracking or whitening in the surface protective layer during the molding process, and the surface has high 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 10, and therefore a step of crosslinking and curing the surface protective layer after producing the decorative resin molded body is unnecessary.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
Evaluation method (1) Breaking elongation and breaking strength of primer layer 40 ± 10 μm each of the primer composition constituting each primer layer shown in Table 1 on the release paper formed by coating the entire surface with a silicone resin to form a release layer. When the primer composition is curable, it is cured by heating at 50 ° C. for 72 hours, and then the coating film is peeled off from the release paper (without heat treatment when the primer composition is not curable). A primer coating film was prepared.
In accordance with JIS K 7127: 1999, a sample of the primer coating having a width of 25 mm × a length (distance between chucks) of 50 mm × a thickness of 40 ± 10 μm is placed in an oven at 120 ° C. and left for 120 seconds, and then a tensile speed : Breaking elongation and breaking strength were measured at 50 mm / min, and were taken as the breaking elongation and breaking strength of the primer layer.

(2) Thermal softening point temperature, softening start temperature and softening completion temperature Thermal softening point temperature, softening start temperature and softening completion of resin composition, primer composition (that is, primer coating film) and substrate after cross-linking and curing The temperature was measured under the following conditions using a thermal analyzer (TMA).
Measurement condition sample: width 5mm x length 15mm
The temperature was raised from room temperature to 180 ° C. at a rate of temperature increase of 10 ° C./min, the softening temperature was determined from the obtained curve, and the softening start and softening completion temperatures were determined from the first derivative curve of the curve.

(3) Storage elastic modulus The resin composition 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 cross-linking 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.

(4) 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.
◎: Good without cracks, breaks, whitening, etc. in the sheet and surface protective layer film ○: Fine cracks and whitening are observed in the 200% stretched part, but there is no practical problem △: Three-dimensional shape part or 200 Minor gloss change or crack occurred in most of the stretched part ×: Significant gloss change, whitening or crack occurred in the entire stretched part <Vacuum forming>
After the decorative sheet is heated to 160 ° C. with an infrared heater and softened, vacuum molding is performed at a maximum draw ratio of 200 times using a mold having the same shape as the female mold for injection molding, and the internal shape of the mold To form. The decorative sheet was released from the mold, and unnecessary parts were trimmed to obtain a molded product.

(5) Formability (injection molding)
The decorative sheets obtained in each Example and Comparative Example were injection molded by the method shown below and evaluated by the appearance after molding. The evaluation criteria are the same as the evaluation criteria in the vacuum forming.
<Injection molding>
The vacuum-formed sheet was placed in a female mold of an injection molding machine, and both male and female molds were clamped, and then the molten ABS resin was injected from the mold gate portion and integrated with the sample to produce 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 opening the mold, the decorative molded product was taken out of the mold to obtain a decorative resin molded product.

(6) 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

(7) Tensile elongation of surface protective layer A woodgrain pattern layer was formed on the back surface of a transparent acrylic resin film having a thickness of 75 μm 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 the surface protective layer (cured film) was cracked, and those having no crack at an elongation of 200% were indicated as> 200.

(8) 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.

Examples 1-5 and Comparative Examples 1-2
A two-part curable urethane-based printing ink is formed on one side of a 60 μm thick transparent polypropylene film that has been subjected to double-sided corona discharge treatment, using a gravure printing method, followed by a gravure on the other side The resin shown in Table 1 is used as a main agent in the printing method, and a two-part curable resin added with isocyanate as a curing agent is applied to Examples 2 to 5 and Comparative Example 1, and cured by heating at 60 ° C. for 48 hours to a thickness of 2 μm. A transparent primer layer was formed. Example 1 and Comparative Example 2 were applied without using a curing agent to form a transparent primer layer having a thickness of 2 μm.
Further, in 33 parts by mass of tetrafunctional urethane acrylate (EB-1, see Table 2), the molar ratio of methyl methacrylate (hereinafter referred to as “MMA”) and methyl acrylate (hereinafter referred to as “MA”) is 100: 5. A copolymer having a weight average molecular weight (Mw) of 1.0 × 10 ⁵ , a number average molecular weight (Mn) of 0.60 × 10 ⁵ and a polydispersity (Mw / Mn) of 1.67 (hereinafter referred to as “PMMA-1”). 67 parts by mass) was obtained, and an electron beam curable resin composition shown in Table 4 as Example 3 was obtained. The mass ratio of EB resin (EB-1): PMMA-1 is 33:67.
Next, the ionizing radiation curable resin composition shown in Table 4 as Example 3 was applied to the entire surface on which the primer layer was formed, and an electron beam (acceleration voltage: 165 KeV, irradiation amount: 5 Mrad) was irradiated. A transparent surface protective layer having a thickness of 5 μm was formed.
An adhesive layer having a thickness of 10 μm made of a two-component curable urethane resin is formed on the pattern layer, and a colored acrylonitrile / butadiene / styrene copolymer [ABS] resin having a thickness of 400 μm is backed on the adhesive layer. The film 20 was bonded by a dry lamination method to obtain a decorative sheet. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 1.
Table 1 shows the breaking elongation and breaking strength of the primer coating, and the heat softening point temperature, softening start temperature and softening completion temperature of the resin composition after crosslinking and curing, the primer coating and the base material.

Examples 3, 6-9 and Comparative Examples 3-4
In the same configuration as the decorative sheet of Example 3, the thickness of the transparent primer layer is changed to 1, 7, 10, and 15 μm to obtain the decorative sheets of Examples 6 to 9, and the transparent primer layer is laminated. The decorative sheet of Comparative Example 3 and the decorative sheet of Comparative Example 4 were obtained in which the thickness of the transparent primer layer was changed to 0.5 μm. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 3.

Examples 10-12
Decorative sheets of Examples 10 to 12 were obtained in the same manner as Example 3 except that the mass ratio of EB resin (EB-1) and PMMA-1 was changed as shown in Table 4. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Example 13
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 3 except that average molecular weight (Mn) 0.46 × 10 ⁵ , polydispersity (Mw / Mn) 2.09, hereinafter referred to as “PMMA-2”, Table 2) Thus, a decorative sheet of Example 13 was obtained. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Example 14
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. Except for using 0 × 10 ⁵ , number average molecular weight (Mn) 0.57 × 10 ⁵ , polydispersity (Mw / Mn) 1.75, hereinafter referred to as “PMMA-3”, Table 2) The decorative sheet of Example 14 was obtained in the same manner as Example 3. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Examples 15 and 16
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) 1.72, the decorative sheet of Example 15 was used in the same manner as in Example 10 except that Table 2-2), hereinafter referred to as “PMMA-4”, was used. Sixteen decorative sheets were obtained. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Examples 17-20
A decorative sheet was obtained in the same manner as in Example 3 except that the thickness of the surface protective layer was changed as described in Table 4. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Examples 21-26
A decorative sheet was obtained in the same manner as in Example 10 except that the film thickness of the surface protective layer was changed as described in Table 4. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Examples 27 and 28
A decorative sheet was obtained in the same manner as in Example 3 except that PMMA-5 or PMMA-6 shown in Table 2 was used instead of PMMA-1. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Examples 29 and 30
A bifunctional urethane acrylate (EB-2, see Table 2) is used instead of EB-1 as the EB resin, and the mass ratio of the EB resin and PMMA-1 is changed as shown in Table 4. Gave a decorative sheet in the same manner as in Example 3. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Example 31
A decorative sheet was obtained in the same manner as in Example 3 except that trifunctional urethane acrylate (EB-3, see Table 2) was used instead of EB-1. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Comparative Example 5
In Example 3, a decorative sheet was obtained in the same manner as in Example 3 except that the EB resin was not used. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Comparative Examples 6 and 7
A decorative sheet was obtained in the same manner as in Example 3 except that the mass ratio of the EB resin and PMMA-1 was changed as described in Table 4. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Comparative Example 8
In Example 3, a decorative sheet was obtained in the same manner as in Example 3 except that PMMA was not used. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Comparative Example 9
A decorative sheet was obtained in the same manner as in Example 3 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 4.

Comparative Examples 10 and 11
A decorative sheet was obtained in the same manner as in Example 3 except that the thickness of the surface protective layer was changed as described in Table 4. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Comparative Examples 12-14
A decorative sheet was obtained in the same manner as in Example 3 except that PMMA-7, PMMA-8 and PMMA-9 shown in Table 2 were used instead of PMMA-1. The decorative sheet was evaluated by the above method. The evaluation results are shown in Table 4.

Comparative Example 15
A decorative sheet was obtained in the same manner as in Example 3 except that bifunctional urethane acrylate (EB-4, see Table 2) 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 4.

Examples 31-35 and Comparative Examples 16-17
A decorative sheet was obtained in the same manner as in Examples 1 to 5 and Comparative Examples 1 and 2, except that the backer film was not laminated. After these decorative sheets are installed so that the base material 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 and softened. The decorative sheet is preformed by vacuum suction from the movable mold side and the softened decorative sheet is brought into close contact with the molding surface of the movable mold, and the decorative sheet is adhered along the molding surface. After the movable mold having the decorative sheet and the fixed mold are clamped, the fluidized ABS resin is injected into the cavity formed by the two molds (injection resin temperature 230 ° C.), filled and solidified. Thus, the formed resin molded body and the decorative sheet were laminated and integrated, and then the movable mold was separated from the fixed mold, and the simultaneous decorative resin molded product in which the entire decorative sheet was laminated was taken out. . The simultaneously decorated resin molded products using the decorative sheets of Examples 31 to 35 were all good without cracking, breaking, whitening, etc. in the sheet and the surface protective layer film. On the other hand, in the simultaneously decorated resin molded product using the decorative sheet of Comparative Example 16 (primer layer: polycarbonate urethane), slight gloss change or cracking occurred in most of the three-dimensional shape part or 200% stretched part. In the simultaneously decorated resin molded article using the decorative sheet of Comparative Example 17 (primer layer: acrylic / vinyl acetate copolymer), fine cracking and whitening were observed in the 200% stretched part.

The decorative sheet having a surface protective layer using the primer layer and the resin composition according to the present invention does not cause cracking or whitening by vacuum forming in a normal insert molding method, and in the injection molding simultaneous decoration method, No cracking or whitening occurs even under the conditions of a rapid temperature drop from the heating temperature of about 160 ° C. to the temperature at the time of contact with the mold, a rapid stretching speed, and a high stretching degree.
Furthermore, it was confirmed that the surface of the decorative resin molded product thus produced has high scratch resistance as well as excellent moldability.

The decorative sheet of the present invention is excellent in vacuum formability, does not generate cracks or whitening on the surface, and has high wear resistance and scratch resistance on the surface, and thus is manufactured using the decorative sheet of the present invention. In the decorative resin molded body, the surface protective layer is not cracked or whitened 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.
Therefore, the decorative resin molded body of the present invention includes, for example, interior materials or exterior materials for vehicles such as automobiles, construction members such as baseboards and fringes, fittings such as window frames and door frames, walls, floors, ceilings, and the like. It is suitable for applications such as housing materials and casings of home appliances such as interior materials of buildings, television receivers and air conditioners.

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. Primer layer 16. Surface protective layer 20. Backer film

Claims (18)

A decorative sheet having at least a primer layer on a substrate and a surface protective layer laminated on the primer layer, the elongation at break at 120 ° C. measured under the following measurement conditions of the primer layer being 200% The resin composition in which the thickness of the primer layer is 0.6 μm or more, and the surface protective layer contains an ionizing radiation curable resin and a thermoplastic resin in a ratio (mass ratio) of 75:25 to 22:78. A product obtained by crosslinking and curing the product, having a polystyrene-reduced weight average molecular weight of 90,000 to 120,000 measured by gel permeation chromatography (GPC) of the thermoplastic resin, and the thickness of the surface protective layer Is a decorative sheet having a thickness of 1 to 1000 μm.
Breaking elongation measurement conditions: Width of 25 mm obtained by forming a primer composition constituting the primer layer (in the case of a curable composition, it is crosslinked and cured by heating at 50 ° C. for 72 hours) in accordance with JIS K 7127: 1999 × Length (distance between chucks) 50 mm × thickness 40 ± 10 μm A sample is placed in an oven at 120 ° C. and left for 120 seconds, and then the elongation at break is measured at a tensile rate of 50 mm / min.   The temperature of the primer composition is higher than the temperature of the resin composition, the thermal softening point temperature, the softening start temperature, and the softening completion temperature of the resin composition, the primer composition, and the base material after crosslinking and curing. The decorative sheet according to claim 1, wherein the temperature of the base material is higher than the temperature of the primer composition. Decorative sheet according to claim 1 or 2 storage elastic modulus at 140 ° C. were measured in the range of ^{1 × 10 5 ~1.2 × 10 8} Pa under the following measurement conditions of the resin composition.
Storage elastic modulus measurement conditions: In accordance with JIS K7244-1 and 7244-4, a sheet of 10 mm width and 15 μm thickness formed by crosslinking and curing the resin composition was 10 mm distance between clamps, start temperature 30 ° C., end The measurement is performed at a temperature of 180 ° C., a heating rate of 5 ° C./min, and a measurement frequency of 1 Hz.   The additive according to any one of claims 1 to 3, wherein the primer composition contains one or more resins selected from (meth) acrylic resins, urethane resins, and (meth) acrylic-urethane copolymer resins. Decorative sheet.   The decorative sheet according to any one of claims 1 to 4, wherein the thermoplastic resin 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 4, wherein the thermoplastic resin is a copolymer of two or more different (meth) acrylic acid ester monomers.   The decorative sheet according to claim 6, wherein the thermoplastic resin is a copolymer of methyl methacrylate and another (meth) acrylic acid ester monomer.   The structural unit derived from another (meth) acrylic acid ester monomer 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. Decorative sheet.   The thermoplastic resin is a copolymer of methyl methacrylate and methyl acrylate, and the structural unit derived from methyl acrylate is 0.1 mol with respect to 100 mol of the structural unit derived from methyl methacrylate in the thermoplastic resin. The decorative sheet according to claim 7, which is in a range of 1 to 10 mol.   The decorative sheet according to any one of claims 1 to 4, wherein the thermoplastic resin 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 in the range of 0.1 to 200 moles with respect to 100 moles of the structural unit derived from (meth) acrylic acid ester in the thermoplastic resin. 10. The decorative sheet according to 10.   The decorative sheet according to any one of claims 1 to 4, wherein the thermoplastic resin is a homopolymer of methyl methacrylate.   The decorative sheet according to any one of claims 1 to 12, wherein the polydispersity of the thermoplastic resin is in a range of 1.1 to 3.0. The decorative sheet according to any one of claims 1 to 13, 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 having a width of 25 mm and a length of 120 mm, tensile elongation until the surface protective layer was cracked under the conditions of a pulling 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 claim 1, wherein the ionizing radiation curable resin is an electron beam curable resin.   A vacuum forming step in which the decorative sheet according to any one of claims 1 to 15 is formed in advance into a three-dimensional shape by a vacuum forming die, a step of trimming excess portions 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 15 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 16 or 17.

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