JP2012139914A - Decorative sheet and decorative resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decorative sheet which has excellent scratch resistance and excellent chemical resistance while maintaining excellent three-dimensional moldability and shape stability, and to provide a decorative resin molded article using the decorative sheet.SOLUTION: The decorative sheet has at least a base material 11, a transparent film 13 and a surface protection layer 15 in this order, the surface protection layer is formed of a cured article of an ionizing radiation-curable resin composition which contains polycarbonate (meth) acrylate and/or acrylic silicone (meth) acrylate. Furthermore, the decorative resin molded article using the decorative sheet is provided.

Description

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

  Decorated resin molded products decorated by laminating decorative sheets on the surface of molded products are used in various applications such as vehicle interior parts. As a molding method of such a decorative resin molded product, the decorative sheet is formed into a three-dimensional shape in advance by a vacuum mold, the molded sheet is inserted into an injection mold, and the resin in a fluid state is placed in the mold. An injection molding method in which the resin and the molded sheet are integrated by injection, or a decorative sheet inserted into the mold at the time of injection molding is integrated with the molten resin injected and injected into the cavity. The injection molding simultaneous decorating method etc. which decorate the surface are mentioned.

  In recent years, physical properties required for a decorative sheet constituting the surface of the decorative resin molded product have been increased from the background that physical properties such as scratch resistance and chemical resistance are increasing. In order to meet such demands, it has been proposed to provide a surface protective layer on the decorative sheet, but since the decorative sheet constitutes the surface of the decorative resin molded product, a certain level of tertiary It is required to improve physical properties such as scratch resistance and chemical resistance while satisfying original moldability (following ability to three-dimensional molding) and shape stability (stability after three-dimensional molding). When the decorative sheet has low three-dimensional properties, the insert molding method is a process of forming the decorative sheet into a three-dimensional (three-dimensional) shape in advance using a vacuum forming mold, and the simultaneous injection decoration method is used when the decorative sheet is pre-formed. Alternatively, when the molten resin is injected, the decorative sheet is stretched along the inner peripheral surface of the cavity and is in close contact, and the decorative sheet is formed into a mold shape by vacuum / pneumatic action, or by pulling due to the pressure of the molten resin or shear stress. Since it extends beyond the minimum necessary amount to conform, there may be a problem that a crack occurs in the surface protective layer of the curved surface portion of the molded product. In addition, if the shape stability is low even if the three-dimensional formability is high, the decorative sheet will be distorted after the three-dimensional forming. It becomes easy.

For the above-mentioned problems, by using an ionizing radiation curable resin such as an ultraviolet curable resin as a surface protective layer and increasing the crosslink density of the resin forming the surface protective layer of the decorative sheet, Although attempts have been made to improve the wear resistance and scratch resistance of the surface, there is still a problem that cracks occur in the curved surface of the molded product during molding.
Further, 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 1). 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, many examples using an acrylic film as a surface protective layer have been reported (see Patent Documents 2 to 4), but recently, physical properties such as scratch resistance and chemical resistance required for decorative sheets, or designs It is not enough to respond to sex.

Japanese Patent Application Laid-Open No. 6-134859 Japanese Patent No. 3598220 Japanese Patent No. 4194670 JP 2008-110532 A

  Under such circumstances, the present invention is a decorative sheet having excellent scratch resistance and chemical resistance while maintaining good three-dimensional formability and shape stability, and a decoration using the decorative sheet It is an object to provide a resin molded product.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the problem can be solved by the following invention. That is, the present invention provides the following decorative sheet and decorative resin molded product.
<1>
A decorative sheet having at least a base material, a transparent film, and a surface protective layer in this order,
A decorative sheet, wherein the surface protective layer is made of a cured product of an ionizing radiation curable resin composition containing polycarbonate (meth) acrylate and / or acrylic silicone (meth) acrylate.
<2>
A decorative resin molded product comprising the decorative sheet according to the above <1> and an injection resin.

  The decorative sheet of the present invention has excellent scratch resistance and chemical resistance while maintaining good three-dimensional formability and shape stability. Therefore, in both the insert molding method and the injection molding simultaneous decoration method, cracks and the like are not formed on the surface, and excellent scratch resistance and chemical resistance can be imparted to the decorated resin molded product.

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

1. Decorative sheet The decorative sheet of the present invention has at least a base material, a transparent film, and a surface protective layer in this order, and the surface protective layer contains polycarbonate (meth) acrylate and / or acrylic silicone (meth) acrylate. It consists of a cured product of the ionizing radiation curable resin composition it contains.
The decorative sheet of the present invention may further have layers other than those as necessary, in addition to the above-described substrate, transparent film, and surface protective layer.
Below, the structure of the decorating sheet | seat of this invention is demonstrated in detail using FIG. FIG. 1 is a schematic diagram showing a cross section of one embodiment of the decorative sheet of the present invention. In this aspect, the decorative sheet 10 includes a base material 11, a pattern layer 12, a transparent film 13, a primer layer 14, and a surface. The protective layer 15 is provided in this order. Note that the present invention is not limited to this mode.

1-1. Surface Protective Layer The surface protective layer 15 is made of a cured product of an ionizing radiation curable resin composition containing polycarbonate (meth) acrylate and / or acrylic silicone (meth) acrylate. By using a specific ionizing radiation curable resin composition for the surface protective layer 15, the decorative sheet 10 can be improved in surface properties such as scratch resistance and chemical resistance without impairing the three-dimensional formability. Can be granted.
In the present invention, the ionizing radiation curable resin composition refers to a composition containing an ionizing radiation curable resin. An ionizing radiation curable resin refers to a resin that crosslinks and cures when irradiated with ionizing radiation. Here, ionizing radiation means an electromagnetic wave or charged particle beam having an energy quantum capable of polymerizing or cross-linking molecules, and usually ultraviolet (UV) or electron beam (EB) is used. It also includes electromagnetic waves such as rays and γ rays, and charged particle rays such as α rays and ion rays.
The ionizing radiation curable resin composition of the present invention contains at least polycarbonate (meth) acrylate and / or acrylic silicone (meth) acrylate as the ionizing radiation curable resin.
In the present invention, “(meth) acrylate” means “acrylate or methacrylate”, and other similar things have the same meaning.

The polycarbonate (meth) acrylate used in the present invention is not particularly limited as long as it has a carbonate bond in the polymer main chain and (meth) acrylate in the terminal or side chain. In addition, this (meth) acrylate preferably has two or more functional groups from the viewpoint of crosslinking and curing.
The polycarbonate (meth) acrylate is obtained, for example, by converting a part or all of the hydroxyl groups of the polycarbonate polyol into (meth) acrylate (acrylic acid ester or methacrylic acid ester). This esterification reaction can be performed by a normal esterification reaction. For example, 1) a method of condensing polycarbonate polyol and acrylic acid halide or methacrylic acid halide in the presence of a base, 2) a method of condensing polycarbonate polyol and acrylic acid anhydride or methacrylic acid anhydride in the presence of a catalyst, Or 3) the method of condensing polycarbonate polyol and acrylic acid or methacrylic acid in the presence of an acid catalyst.

The polycarbonate polyol is a polymer having a carbonate bond in the polymer main chain and having 2 or more, preferably 2 to 50, more preferably 3 to 50 hydroxyl groups at the terminal or side chain. A typical method for producing this polycarbonate polyol is a method by a polycondensation reaction from a diol compound (A), a trihydric or higher polyhydric alcohol (B), and a compound (C) to be a carbonyl component.
The diol compound (A) used as a raw material is represented by the general formula HO—R ₁ —OH. Here, R < ₁ > is a C2-C20 bivalent hydrocarbon group, Comprising: The group may contain the ether bond. For example, a linear or branched alkylene group, a cyclohexylene group, or a phenylene group.

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

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

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

The polycarbonate polyol is synthesized by subjecting the above-described diol compound (A), a trihydric or higher polyhydric alcohol (B), and a compound (C) to be a carbonyl component to a polycondensation reaction under general conditions. . For example, the charged molar ratio of the diol compound (A) to the polyhydric alcohol (B) is preferably in the range of 50:50 to 99: 1, and the diol compound (C) as the carbonyl component ( The charged molar ratio of A) to the polyhydric alcohol (B) is preferably 0.2 to 2 equivalents with respect to the hydroxyl group of the diol compound and polyhydric alcohol.
The number of equivalents (eq./mol) of hydroxyl groups present in the polycarbonate polyol after the polycondensation reaction at the above charge ratio is 3 or more on average in one molecule, preferably 3 to 50, more preferably 3 to 20. Within this range, a necessary amount of (meth) acrylate groups are formed by the esterification reaction described later, and moderate flexibility is imparted to the polycarbonate (meth) acrylate resin. The terminal functional group of this polycarbonate polyol is usually an OH group, but a part thereof may be a carbonate group.
The method for producing the polycarbonate polyol described above is described in, for example, JP-A No. 64-1726. The polycarbonate polyol can also be produced by an ester exchange reaction between a polycarbonate diol and a trihydric or higher polyhydric alcohol as described in JP-A-3-181517.

  The molecular weight of the polycarbonate (meth) acrylate used in the present invention is preferably 500 or more, more preferably 1,000 or more, as measured by GPC analysis and converted to standard polystyrene. More preferably, it exceeds 2,000. The upper limit of the weight average molecular weight of the polycarbonate (meth) acrylate is not particularly limited, but is preferably 100,000 or less and more preferably 50,000 or less from the viewpoint of controlling the viscosity not to be too high. From the viewpoint of achieving both scratch resistance and three-dimensional formability, it is more preferably more than 2,000 and not more than 50,000, and particularly preferably 5,000 to 20,000.

  In the acrylic silicone (meth) acrylate used in the present invention, a part of the structure of the acrylic resin is substituted with a siloxane bond (Si—O) in one molecule, and the side chain of the acrylic resin and / Or it will not be specifically limited if it has two or more (meth) acryloyloxy groups (acryloyloxy group or methacryloyloxy group) in the principal chain terminal. As an example of this acrylic silicone (meth) acrylate, the structure of the acrylic resin which has a siloxane bond in a side chain as disclosed by Unexamined-Japanese-Patent No. 2007-070544 is mentioned preferably, for example.

The acrylic silicone (meth) acrylate used in the present invention can be synthesized, for example, by radical copolymerizing a silicone macromonomer with a (meth) acrylate monomer in the presence of a radical polymerization initiator.
Examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, and the like. These (meth) acrylate monomers are used alone or in combination of two.

  The silicone macromonomer is synthesized, for example, by living anionic polymerization of hexaalkylcyclotrisiloxane using n-butyllithium or lithium silanolate as a polymerization initiator and capping with a radically polymerizable unsaturated group-containing silane. As the silicone macromonomer, a compound represented by the following formula (1) is preferably used.

In formula (1), R ¹ represents an alkyl group having 1 to 4 carbon atoms, a methyl group or an n- butyl group are preferable. R ² represents a monovalent organic group, —CH═CH ₂ , —C ₆ H ₄ —CH═CH ₂ , — (CH ₂ ) ₃ O (CO) CH═CH ₂ or — (CH ₂ ) _3. O (CO) C (CH ₃ ) ═CH ₂ is preferred. R ^{3 s} may be the same or different and each represents a hydrocarbon group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, and more preferably a methyl group. The numerical value of n is not particularly limited, and for example, the number average molecular weight of the silicone macromonomer is preferably 1,000 to 30,000, and more preferably 1,000 to 20,000.

  The acrylic silicone (meth) acrylate obtained using the above-mentioned raw materials has structural units represented by the following formulas (2), (3) and (4), for example.

In formulas (2), (3) and (4), R ¹ and R ³ have the same meanings as in formula (1), R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents the (meth) acrylate. An alkyl group or glycidyl group in the monomer, or an alkyl group which may have a functional group such as an alkyl group or glycidyl group in the (meth) acrylate monomer, and R ⁶ is an organic compound having a (meth) acryloyloxy group. Indicates a group.
The above-mentioned acrylic silicone (meth) acrylates are used alone or in combination of two.

The molecular weight of the acrylic silicone (meth) acrylate is preferably 1,000 or more, more preferably 2,000 or more, as measured by GPC analysis and converted to standard polystyrene. . The upper limit of the weight average molecular weight of the acrylic silicone (meth) acrylate is not particularly limited, but is preferably 150,000 or less and more preferably 100,000 or less from the viewpoint of controlling the viscosity not to be too high. From the viewpoint of balancing the three-dimensional formability, chemical resistance and scratch resistance, it is particularly preferably 2,000 to 100,000.
Moreover, it is preferable that the average molecular weight between crosslinking points of acrylic silicone (meth) acrylate is 100-2,500. If the average molecular weight between crosslinking points is 100 or more, it is preferable from the viewpoint of three-dimensional formability, and if it is 2,500 or less, it is preferable from the viewpoint of chemical resistance and scratch resistance.

  In the ionizing radiation curable resin composition of the present invention, the polycarbonate (meth) acrylate and the acrylic silicone (meth) acrylate may be used alone or in combination.

The ionizing radiation curable resin composition used in the present invention preferably contains a polyfunctional (meth) acrylate. The polyfunctional (meth) acrylate is not particularly limited as long as it is a bifunctional or higher (meth) acrylate. However, from the viewpoint of improving curability, a tri- or higher functional (meth) acrylate is preferable, and from the viewpoint of improving three-dimensional moldability, a bifunctional (meth) acrylate is preferable. Here, the n function means having n ethylenically unsaturated bonds {(meth) acryloyl group or (meth) acryloyloxy group} in the molecule.
The polyfunctional (meth) acrylate may be either an oligomer or a monomer, but a polyfunctional (meth) acrylate oligomer is preferable from the viewpoint of improving three-dimensional moldability.

Examples of the polyfunctional (meth) acrylate oligomer include urethane (meth) acrylate oligomers, epoxy (meth) acrylate oligomers, polyester (meth) acrylate oligomers, and polyether (meth) acrylate oligomers. In addition to these, polybutadiene oligomers with a highly hydrophobic polybutadiene (meth) acrylate oligomer with (meth) acrylate groups in the side chain, silicone (meth) acrylate oligomers with polysiloxane bonds in the main chain, small molecules Examples thereof include aminoplast resin (meth) acrylate oligomers obtained by modifying aminoplast resins having many reactive groups.
Moreover, you may use together the oligomer which has a cation polymerizable functional group in molecules, such as a novolak-type epoxy resin, a bisphenol-type epoxy resin, aliphatic vinyl ether, and aromatic vinyl ether, with said polyfunctional (meth) acrylate oligomer.

Examples of the polyfunctional (meth) acrylate monomer include trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri ( (Meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified 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 Such Ruhekisa (meth) acrylate.
The polyfunctional (meth) acrylate oligomer and polyfunctional (meth) acrylate monomer described above may be used alone or in combination of two or more.

When polyfunctional (meth) acrylate is used in combination with polycarbonate (meth) acrylate, the mass ratio of polycarbonate (meth) acrylate / polyfunctional (meth) acrylate is preferably 98/2 to 70/30. Within this range, scratch resistance, chemical resistance and three-dimensional formability can be simultaneously satisfied at a high level. The mass ratio is more preferably 95/5 to 80/20.
When polyfunctional (meth) acrylate is used in combination with acrylic silicone (meth) acrylate, the mass ratio of acrylic silicone (meth) acrylate / polyfunctional (meth) acrylate is preferably in the range of 95/5 to 50/50. Within this range, scratch resistance, chemical resistance and three-dimensional formability can be simultaneously satisfied at a high level. The mass ratio is more preferably 90/10 to 60/40.

  In the present invention, together with the polyfunctional (meth) acrylate and the like, a monofunctional (meth) acrylate can be appropriately used in combination as long as the object of the present invention is not impaired for the purpose of reducing the viscosity. These monofunctional (meth) acrylates may be used individually by 1 type, and may be used in combination of 2 or more type.

When using an ultraviolet curable resin composition as the ionizing radiation curable resin composition, it is desirable to add about 0.1 to 5 parts by mass of the photopolymerization initiator to 100 parts by mass of the ultraviolet curable resin. . The initiator for photopolymerization can be appropriately selected from those conventionally used and is not particularly limited.
In the present invention, it is preferable to use an electron beam curable resin composition as the ionizing radiation curable resin composition. This is because the electron beam curable resin composition can be made solvent-free, is more preferable from the viewpoint of environment and health, and does not require a photopolymerization initiator, and can provide stable curing characteristics.

Various additives can be blended in the ionizing radiation curable resin composition constituting the surface protective layer 15 depending on the desired physical properties of the resulting cured resin layer. Examples of the additives include weather resistance improvers such as ultraviolet absorbers and light stabilizers, wear resistance improvers, polymerization inhibitors, crosslinking agents, infrared absorbers, antistatic agents, adhesion improvers, and leveling agents. , Thixotropic agent, coupling agent, plasticizer, antifoaming agent, filler, solvent, colorant and the like. These additives can be appropriately selected from those commonly used.
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. In addition, the polymer of the present invention can be used after being copolymerized to such an extent that the performance as a surface protective layer is not impaired.

The thickness of the surface protective layer 15 after curing is preferably 1 to 1,000 μm. If the thickness of the surface protective layer 15 after curing is 1 μm or more, sufficient physical properties as a protective layer such as scratch resistance, chemical resistance, and weather resistance can be obtained. On the other hand, if the thickness of the surface protective layer 15 after curing is 1,000 μm or less, it is easy to uniformly apply ionizing radiation, it is easy to obtain uniform curing, and this is economically advantageous.
Moreover, the thickness after hardening of the surface protective layer 15 is more preferably 1 to 50 μm, and further preferably 1 to 30 μm, from the viewpoint of three-dimensional formability. In the said range, the high followable | trackability to complicated three-dimensional shapes, such as a car interior use, can be acquired.
The surface protective layer 15 of the present invention can exhibit excellent three-dimensional formability even when a hard ionizing radiation curable resin is blended. That is, the coating film can be hardened without impairing the three-dimensional formability, and excellent scratch resistance and chemical resistance can be imparted to the decorative sheet 10.
The decorative sheet of the present invention can obtain a sufficiently high three-dimensional formability even if the thickness of the surface protective layer is larger than that of the conventional one. For example, it is also useful as a decorative sheet for vehicle exterior parts.

The surface protective layer 15 is prepared by preparing a coating liquid containing the ionizing radiation curable resin composition described above, and applying the prepared coating liquid on the surface of the primer layer 14 (if the primer layer 14 is not provided, the surface protective layer 15 is transparent. It can be obtained by coating on the surface of the film 13 to form an uncured resin layer, and crosslinking and curing the uncured resin layer.
Examples of the coating method include known methods such as gravure coating, bar coating, roll coating, reverse roll coating, and comma coating, and gravure coating is preferable.
The viscosity of the coating solution is not particularly limited as long as it is a viscosity capable of forming an uncured resin layer on the surface of the substrate.

In the present invention, the uncured resin layer is cured by irradiating the uncured resin layer 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 transparent film that deteriorates due to an electron beam is used as the transparent film 13, the transmission depth of the electron beam and the thickness of the resin layer are By selecting the accelerating voltage so as to be substantially equal, irradiation of the extra electron beam to the transparent film 13 can be suppressed, and deterioration of the substrate due to the excess electron beam can be minimized. .
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, anti-fouling coating function having high hardness and scratch resistance, 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.

1-2. Transparent film The transparent film 13 contributes to further improvement in chemical resistance of the decorative sheet 10. That is, depending on the type and amount of the chemical, the chemical may penetrate into the base material 11 of the decorative sheet 10 and damage the base material 11, but the damage can be reduced by providing the transparent film 13. It becomes possible. The “transparent” of the transparent film 13 includes not only colorless and transparent but also translucent and colored and transparent.

  The transparent film 13 is appropriately determined in consideration of transparency, three-dimensional formability, shape stability, chemical resistance, and the like. Typically, a thermoplastic resin film is used. Examples of the thermoplastic resin generally include acrylic resins, polyolefin resins such as polypropylene and polyethylene, polycarbonate resins, acrylonitrile-butadiene-styrene resins (hereinafter referred to as “ABS resins”), polyester resins, and vinyl chloride resins. used. Among these, from the viewpoint of chemical resistance, polyester resins, polyolefin resins, acrylic resins and polycarbonate resins are preferable, polyester resins and polyolefin resins are more preferable, and polyester resins are more preferable. The thermoplastic resin may be crystalline or amorphous, but is preferably crystalline from the viewpoint of chemical resistance, and amorphous from the viewpoint of three-dimensional moldability. Preferably there is.

The transparent film 13 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 with 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.
The thickness of the transparent film 13 is not particularly limited, but is preferably 10 to 200 μm and more preferably 15 to 150 μm in view of cost, three-dimensional formability, shape stability, and the like.

1-3. Base Material The base material 11 is appropriately selected in consideration of the three-dimensional moldability, compatibility with the resin to be injection-molded, and the like. Typically, a thermoplastic resin sheet is used. As the thermoplastic resin, ABS resin, acrylic resin, polyolefin resin such as polypropylene and polyethylene, polycarbonate resin, vinyl chloride resin and the like are generally used. Among these, ABS resin, polyolefin resin, and acrylic resin are preferable, and ABS resin is more preferable. 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.

The thickness of the substrate 11 is not particularly limited, but is preferably 50 to 1,000 μm and more preferably 200 to 800 μm in consideration of cost, three-dimensional formability, shape stability, and the like. Moreover, it is preferable from a viewpoint of shape retainability that the thickness of the base material 11 is 2 times or more of the thickness of the transparent film 13.
The flexural modulus of the base material 11 is preferably 1500 to 3000 MPa. When the flexural modulus is 1500 MPa or more, the moldability is good, and particularly the shape stability after vacuum forming is excellent. Moreover, the surface hardness represented by the pencil hardness test is improved, and the decorative sheet can be made strong against damage caused by so-called scooping. On the other hand, when the flexural modulus is 3000 MPa or less, sufficient three-dimensional formability can be ensured. From the above viewpoint, the flexural modulus of the base material 11 is more preferably in the range of 1700 to 2600 MPa. The flexural modulus is measured according to JIS K7171 (ISO178).

The base material 11 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 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.
The base material 11 may be subjected to a treatment such as forming a primer layer, or may be preliminarily formed with a coating for adjusting the color or a pattern from a design viewpoint.

1-4. Picture layer The picture layer 12 gives decorativeness to the decorated resin molded product, and is a layer provided as desired. The pattern layer 12 is formed by printing various patterns using an ink composition and a printing machine. As a printing method, a normal printing method such as gravure printing can be employed. The pattern layer 12 may be printed on the transparent film 13 or may be printed on the substrate 11, but is preferably printed on the transparent film 13 from the viewpoint of manufacturing.
Patterns include stone patterns that simulate the surface of rocks such as wood grain patterns, marble patterns (for example, travertine marble patterns), fabric patterns that simulate cloth and cloth-like patterns, tiled patterns, brickwork patterns, 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 constituting the pattern. Is done.
The thickness of the pattern layer 12 is appropriately selected depending on the pattern.

As the ink composition 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, metal pigments made of scaly foil pieces such as aluminum and brass, pearlescent pigments made of scaly foil pieces such as titanium dioxide-coated mica and basic lead carbonate, and the like are used.

1-5. Hiding layer A hiding layer (not shown) is a layer provided between the base material 11 and the pattern layer 12 as desired. It 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 substrate 11. The concealing layer is formed by a normal printing method such as gravure printing or a normal coating method such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating.
The hiding layer is usually formed with an opaque color, and a so-called solid printing layer having a thickness of about 1 to 20 μm is preferably used. The ink composition for forming the concealing layer can be appropriately selected from those used for the pattern layer 12 described above and employed.

1-6. Primer Layer The primer layer 14 has an effect of making it difficult for fine cracks and whitening to occur in the stretched portion of the surface protective layer 15, and is a layer provided as desired.
The thickness of the primer layer 14 is preferably about 0.1 to 10 μm, and more preferably 1 to 10 μm. When it is 0.1 μm or more, the effect of preventing the surface protective layer from cracking, breaking, whitening, etc. can be sufficiently exerted. On the other hand, if the thickness of the primer layer is 10 μm or less, it is preferable that the three-dimensional formability does not fluctuate since the drying and curing of the coating film is stable when the primer layer is applied.

  The primer layer 14 is a gravure coat, gravure reverse coat, gravure offset coat, spinner coat, roll coat, reverse roll coat, kiss coat, wheeler coat, dip coat, silk screen solid coat, wire bar coat, flow coat, comma coat, coat It is formed by a usual coating method such as sink coating, brush coating, spray coating, or transfer coating method. The transfer coating method is a method in which a coating film of the primer layer 14 is once formed on a thin sheet (film substrate), and then the target layer surface in the decorative sheet 10 is coated.

The primer composition constituting the primer layer 14 is (meth) acrylic resin, urethane resin, (meth) acrylic / urethane copolymer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, butyral resin, chlorinated polypropylene, Chlorinated polyethylene or the like is used.
(Meth) acrylic resins include (meth) acrylic acid ester homopolymers, copolymers of two or more different (meth) acrylic acid ester monomers, or (meth) acrylic acid esters and other monomers. Polymers, and specifically, poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate propyl, poly (meth) acrylate butyl, methyl (meth) acrylate (Meth) butyl acrylate copolymer, (meth) ethyl acrylate / (meth) butyl acrylate copolymer, ethylene / (meth) methyl acrylate copolymer, styrene / methyl (meth) acrylate copolymer A (meth) acrylic resin composed of a homopolymer or a copolymer containing a (meth) acrylic acid ester such as is preferably used. 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.

1-7. Adhesive Layer An adhesive layer (not shown) is provided on the back surface of the base material 11 (the surface opposite to the surface protective layer 15) as desired in order to improve the adhesion between the decorative sheet 10 and the injection resin. Layer. A thermoplastic resin or a curable resin is used for the adhesive layer depending on 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 urethane resin and epoxy resin.
The thickness of the adhesive layer is not particularly limited, but is preferably about 0.1 to 10 μm.
For the adhesive layer, the same coating method as that of the primer layer 14 can be adopted as a coating method.

2. Decorated resin molded product The decorated resin molded product of the present invention includes the decorated sheet of the present invention and an injection resin.
The injection resin is not particularly limited, but is typically 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. In addition, thermosetting resins such as urethane resins and epoxy resins can be used depending on the application.

  The decorative resin molded product of the present invention is a variety of injection molding methods such as insert molding, simultaneous injection molding, blow molding, gas injection molding, etc., preferably insert molding, using the decorative sheet of the present invention. And the injection molding simultaneous decoration method.

  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.

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. .

  The decorative resin molded body produced as described above has good three-dimensional moldability without cracking in the surface protective layer during the molding process, and the surface has high scratch resistance. In addition, the solvent resistance and chemical resistance are high. 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.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
Evaluation method (1) Three-dimensional formability The decorative sheets obtained in Examples and Comparative Examples described later were heated to 160 ° C. with an infrared heater and softened. Next, vacuum forming was performed using a vacuum forming die (maximum draw ratio: 100%) to form the internal shape of the die. After cooling the sheet, the decorative sheet was released from the mold. The evaluation criteria are as follows.
◎: No problem ○: Fine coating cracking or whitening was observed in a part of the three-dimensional shape portion or the maximum stretched portion, but there was no practical problem.
Δ: Slight coating cracking or whitening occurred in a part of the three-dimensional shape portion or the maximum stretched portion.
X: The coating film cracking and whitening were observed in the surface protective layer without following the shape of the mold.
XX: The sheet was too hard to be vacuum formed.
(2) Shape stability The above-mentioned decorative sheet after release was allowed to stand at room temperature for 1 week, and shape distortion and shrinkage were confirmed. The evaluation criteria are as follows.
A: No distortion in shape B: Slight distortion occurred in shape, but no problem in practical use X: Shape was significantly distorted, and the shape during vacuum forming could not be maintained.

(3) Scratch resistance The decorative sheets obtained in the examples and comparative examples were reciprocated five times with a load of 1.5 kgf using # 0000 steel wool, and then the appearance was evaluated. The evaluation criteria are as follows.
A: There was no scratch.
○: Although fine scratches were observed on the surface, the coating film was not scraped or whitened.
Δ: Minor scratches on the surface.
X: The surface was markedly damaged.

(4) Chemical resistance 0.5 g of insect repellent spray (N, N-diethyl-m-toluamide 10%) was applied to the sheet pieces 10 cm × 10 cm of the decorative sheets obtained in Examples and Comparative Examples. After leaving it in an oven at 60 ° C. for 30 minutes, it was removed from the oven and allowed to cool to room temperature. Then, it washed with water using the neutral detergent and confirmed the external appearance.
A: No change in appearance.
○: Extremely slight whitening and swelling were observed on the surface, but no significant whitening, swelling or dissolution was observed.
Δ: Slight whitening, swelling, and dissolution were observed on the surface.
X: There was remarkable whitening, swelling and dissolution on the surface.

(5) Measurement of molecular weight A high-speed GPC apparatus manufactured by Tosoh Corporation was used. The column used was “TSKgel αM” 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. . In addition, the weight average molecular weight in this invention is the value which performed polystyrene conversion.

Examples 1-8, Comparative Examples 4-5
Corona treatment was performed on both surfaces of the transparent film shown in Table 1. A woodgrain pattern layer was formed on one surface of the transparent film by gravure printing using an acrylic resin ink. On the other side, an ink obtained by mixing an acrylic polyol / polyurethane mixed resin with dihexamethylene isocyanate so as to have an NCO equivalent as a primer layer was printed to a thickness of 1 μm.
Next, an electron beam curable resin composition having the composition shown in Table 1 was applied to the surface of the primer layer by gravure reverse so that the thickness after curing was 10 μm. This uncured resin layer was irradiated with an electron beam having an acceleration voltage of 165 kV and an irradiation dose of 50 kGy (5 Mrad) to cure the electron beam curable resin composition, thereby producing a printed film.
An adhesive made of urethane resin was applied to the surface of the pattern layer of the printed film by gravure reverse so as to have a thickness of 10 μm after drying, and was bonded to the substrate shown in Table 1. This was cured at room temperature for 1 week to obtain a decorative sheet.

Comparative Examples 1-3
One side of the transparent film shown in Table 1 was subjected to corona treatment. A woodgrain pattern layer was formed on the surface of the transparent film subjected to corona treatment by gravure printing using an acrylic resin ink.
Next, an adhesive made of urethane resin was applied to the surface of the pattern layer by gravure reverse so as to have a thickness of 10 μm after drying, and bonded to the base material shown in Table 1. This was cured at room temperature for 1 week to obtain a decorative sheet.

Comparative Example 6
One side of the substrate shown in Table 1 was subjected to corona treatment. A woodgrain pattern layer was formed by gravure printing using an acrylic resin ink on the corona-treated surface of the substrate. Next, an ink prepared by mixing dihexamethylene isocyanate with an acrylic polyol / polyurethane mixed resin so as to have an NCO equivalent as a primer layer on the surface of the pattern layer was printed to a thickness of 1 μm.
Next, an electron beam curable resin composition having the composition shown in Table 1 was applied to the surface of the primer layer by gravure coating so that the thickness of the resin composition after curing was 10 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. This was cured at room temperature for 1 week to obtain a decorative sheet.

[note]
EB1: bifunctional polycarbonate acrylate (weight average molecular weight: 10,000): hexafunctional urethane acrylate oligomer (weight average molecular weight: 6,000) = 90: 10 (mass ratio)
EB2; bifunctional polycarbonate acrylate (weight average molecular weight: 10,000): hexafunctional urethane acrylate oligomer (weight average molecular weight: 6,000) = 70: 30 (mass ratio)
EB3; acrylic silicone acrylate (weight average molecular weight: 20,000, molecular weight between crosslinks after curing 200): hexafunctional urethane acrylate oligomer (weight average molecular weight: 5,000) = 70: 30 (mass ratio)
EB4; acrylic silicone acrylate (weight average molecular weight: 20,000, molecular weight between crosslinks after curing 200): hexafunctional urethane acrylate oligomer (weight average molecular weight: 5,000) = 90: 10 (mass ratio)
EB5; hexafunctional urethane acrylate oligomer (weight average molecular weight: 20,000)
EB6; bifunctional urethane acrylate oligomer (weight average molecular weight: 20,000)
PET1; crystalline PET
PET2: Amorphous PET (PET-G)
PET3: Amorphous PET (A-PET)
ABS1: Flexural modulus 1,800 MPa
ABS2: Flexural modulus of 2500 MPa

  In the decorative sheet (Examples 1 to 8) of the present invention, a surface protective layer is formed using a specific ionizing radiation curable resin composition, and a transparent film is provided, so that the level is satisfactory for practical use. It was confirmed that excellent scratch resistance and chemical resistance were exhibited while maintaining three-dimensional formability and shape stability.

  The decorative sheet of the present invention is used for various decorative resin molded products, for example, interior materials or exterior materials of vehicles such as automobiles, construction members such as baseboards, and rims, joinery such as window frames and door frames, and walls. It is suitably used for decorative resin molded products for uses such as interior materials for buildings such as floors and ceilings, casings and containers of household electrical appliances such as television receivers and air conditioners.

10. Decorative sheet Base material 12. Pattern layer 13. Transparent film 14. Primer layer 15. Surface protective layer

Claims (7)

A decorative sheet having at least a base material, a transparent film, and a surface protective layer in this order,
A decorative sheet, wherein the surface protective layer is made of a cured product of an ionizing radiation curable resin composition containing polycarbonate (meth) acrylate and / or acrylic silicone (meth) acrylate.   The ionizing radiation curable resin composition contains polycarbonate (meth) acrylate and polyfunctional (meth) acrylate, and the mass ratio of polycarbonate (meth) acrylate / polyfunctional (meth) acrylate is 98/2 to 70/30. The decorative sheet according to claim 1, wherein   The decorative sheet according to claim 1 or 2, wherein the polycarbonate (meth) acrylate has a weight average molecular weight exceeding 2,000.   The ionizing radiation curable resin composition contains acrylic silicone (meth) acrylate and polyfunctional (meth) acrylate, and the mass ratio of acrylic silicone (meth) acrylate / polyfunctional (meth) acrylate is 95/5 to 50. The decorative sheet according to claim 1, which is / 50.   The decorative sheet according to claim 1 or 4, wherein the acrylic silicone (meth) acrylate has a weight average molecular weight of 2,000 to 100,000.   The decorative sheet according to any one of claims 2 to 5, wherein the polyfunctional (meth) acrylate is a trifunctional or higher functional (meth) acrylate.   A decorative resin molded product comprising the decorative sheet according to any one of claims 1 to 6 and an injection resin.

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