Decorative sheet, decorative resin molding, and method for manufacturing decorative resin molding

Abstract

To provide a decorative sheet which is suitably fixed to a mold by applying static electricity on the decorative sheet.SOLUTION: A decorative sheet has at least a surface protective layer, wherein the surface resistance values of all the layers contained in the decorative sheet are 1011 Ω / sq. or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a decorative sheet, a decorated resin molded product, and a method for manufacturing a decorated resin molded product. [Background technology]

[0002] Decorative resin molded products in which a decorative sheet is laminated on the surface of a resin molded product are used for vehicle interior parts, building material interior materials, home appliance housings, etc. Known molding methods for such decorative resin molded products include an insert molding method (see, for example, Patent Document 1) in which a decorative sheet is molded into a three-dimensional shape in advance using a vacuum molding die, and the molded sheet is inserted into an injection molding die and a resin in a fluid state is injected into the die to integrate the resin and the molded sheet, and an overlay method (see, for example, Patent Document 2) in which a decorative sheet is attached to a previously molded resin molded body while applying heat and pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-322501 A [Patent Document 2] JP 2012-101549 A Summary of the Invention [Problem to be solved by the invention]

[0004] When manufacturing a decorated resin molded product using a decorative sheet, the decorative sheet is placed in a mold and a molding process such as vacuum heat molding, injection molding, etc. In these molding processes, a method of fixing the decorative sheet to the mold can be considered in which the decorative sheet is charged and electrodynamically fixed to the mold.

[0005] However, in conventional decorative sheets, when a decorative layer containing a conductive pigment such as a carbon pigment or an aluminum pigment is provided, static electricity may dissipate from the charged decorative sheet, causing the decorative sheet to fall off the mold and disrupting the molding process.

[0006] In this situation, the main object of the present disclosure is to provide a decorative sheet that can be suitably fixed to a mold by charging the decorative sheet with static electricity. Another object of the present disclosure is to provide a decorated resin molded product using the decorative sheet and a manufacturing method thereof. [Means for solving the problem]

[0007] The inventors of the present disclosure have conducted intensive research to solve the above problems. As a result, they have found that, in a decorative sheet having at least a surface protective layer, even if the surface resistance of both sides of the decorative sheet is set high, the decorative sheet may not be sufficiently fixed to a mold by charging it. Based on this finding, the inventors of the present disclosure have conducted further research and found that when the surface resistance of all layers included in the decorative sheet is set to a predetermined value or higher, the decorative sheet can be suitably fixed to a mold by electrostatic charging.

[0008] The present disclosure has been completed based on the above findings and through further investigation.

[0009] That is, the present disclosure provides the inventions of the following aspects. Item 1. A decorative sheet having at least a surface protective layer, The surface resistance of all layers included in the decorative sheet is 10 11 A decorative sheet with a surface area of ​​Ω / sq. or more. Item 2. The decorative sheet according to item 1, further comprising a decorative layer. Item 3. The decorative sheet according to item 2, wherein the decorative layer contains at least one of a carbon pigment and an aluminum pigment. Item 4. The decorative sheet according to item 2 or 3, wherein the decorative sheet is composed of a laminate including at least a base layer, the decorative layer, a primer layer, and the surface protective layer in this order. Item 5. A decorated resin molded product comprising a molded resin layer and a decorative sheet according to any one of items 1 to 4 laminated thereon, The surface resistance of all layers included in the decorative sheet is 10 11 Decorative resin moldings with a surface roughness of Ω / sq. or more. Item 6. A step of charging the decorative sheet according to any one of items 1 to 4 with static electricity and fixing the decorative sheet to a mold; a step of integrating the decorative sheet and the molded resin layer by injecting a resin into the mold; A method for manufacturing a decorated resin molded product comprising the steps of: Effect of the Invention

[0010] According to the present disclosure, a decorative sheet that is suitably fixed to a mold can be provided by charging the decorative sheet with static electricity. The decorative sheet of the present disclosure can be suitably fixed to a mold, so that the molding process of the decorative sheet can be carried out easily and suitably. In addition, according to the present disclosure, a decorated resin molded product using the decorative sheet and a manufacturing method thereof can be provided. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram of a cross-sectional structure of one embodiment of a decorative sheet according to the present disclosure before heating. [Diagram 2] FIG. 2 is a schematic diagram of a cross-sectional structure of one embodiment of a decorative sheet according to the present disclosure after heating. [Diagram 3] FIG. 2 is a schematic diagram of a cross-sectional structure of one embodiment of a decorative sheet according to the present disclosure before heating. [Figure 4] 1 is a schematic diagram of a cross-sectional structure of one embodiment of a decorated resin molded product according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 1.Decorative sheet The decorative sheet of the present disclosure includes at least a surface protective layer, and the surface resistance of all layers included in the decorative sheet is 10 11 The decorative sheet of the present disclosure has a characteristic of being equal to or more than Ω / sq. Since the decorative sheet of the present disclosure has such a configuration, the decorative sheet can be suitably fixed to a mold by charging the decorative sheet with static electricity.

[0013] The decorative sheet of the present disclosure will be described in detail below with reference to FIG. 1 to FIG. 4. In this specification, the numerical range indicated by "~" means "more than or equal to" or "less than or equal to". For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less. In the numerical ranges described in the present disclosure in stages, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. In addition, the upper limit and the upper limit, the upper limit and the lower limit, or the lower limit and the lower limit, each of which is described separately, may be combined to form a numerical range. In addition, in the numerical ranges described in the present disclosure, the upper limit or the lower limit described in a certain numerical range may be replaced with a value shown in the examples. In addition, in this specification, "(meth)acrylate" means "acrylate or methacrylate", and other similar terms have the same meaning.

[0014] Laminated structure and physical properties of decorative sheets The decorative sheet 10 of the present disclosure includes at least a surface protective layer 1, as shown in, for example, FIGS.

[0015] The decorative sheet 10 of the present disclosure may further include at least one layer selected from the group consisting of a base layer 2, a primer layer 3, a decorative layer 4, and a back adhesive layer (not shown) in addition to the surface protective layer 1. As described above, in the case of a conventional decorative sheet, when a decorative layer or the like is provided, static electricity may dissipate from the charged decorative sheet, causing the decorative sheet to fall off from the mold and hinder the molding process. This is likely to occur when a conductive pigment or the like is blended into the decorative layer. Since the decorative sheet is usually placed on the mold side with the surface protective layer side and fixed to the mold, it was thought that by setting the surface resistance value of at least the surface protective layer side high, the decorative sheet would be suitably charged with static electricity and suitably fixed to the mold. However, the inventor of the present disclosure has found that, for example, in a decorative sheet in which a conductive pigment or the like is blended into the decorative layer, even if the surface resistance values ​​of both sides of the decorative sheet are set high, the decorative sheet may not be sufficiently fixed to the mold by charging it. In contrast, the decorative sheet of the present disclosure has a surface resistance value of 10% or more for all layers included in the decorative sheet. 11 By setting the resistance to Ω / sq. or more, the decorative sheet can be suitably charged with static electricity and fixed to the mold.

[0016] The decorative sheet of the present disclosure may further include one or more other layers laminated at any position depending on the function to be imparted to the decorative sheet or the decorated resin molded article.

[0017] Examples of the laminated structure of the decorative sheet of the present disclosure include a laminated structure in which a base layer / surface protective layer are laminated; a laminated structure in which a base layer / decorative layer / surface protective layer are laminated in this order; a laminated structure in which a base layer / decorative layer / primer layer / surface protective layer are laminated in this order; and a laminated structure in which a back adhesive layer / base layer / decorative layer / primer layer / surface protective layer are laminated in this order. FIG. 1 shows a schematic cross-sectional view of an example of a decorative sheet in which a base layer / surface protective layer are laminated in this order as one embodiment of the laminated structure of the decorative sheet of the present disclosure. FIG. 2 shows a schematic cross-sectional view of an example of a decorative sheet in which a base layer / primer layer / surface protective layer are laminated in this order as one embodiment of the laminated structure of the decorative sheet of the present disclosure. FIG. 3 shows a schematic cross-sectional view of an example of a decorative sheet in which a base layer / decorative layer / primer layer / surface protective layer are laminated in this order as one embodiment of the laminated structure of the decorative sheet of the present disclosure.

[0018] The surface resistance of all layers included in the decorative sheet of the present disclosure is 10 11 The surface resistance of all layers included in the decorative sheet of the present disclosure is preferably 10 13 The surface resistance of each layer is Ω / sq. or more. To measure the surface resistance of each layer, a sample in which each of these layers is formed on a PET film with a thickness of 50 μm is prepared, and a commercially available surface resistance meter having conductive silicon electrodes (electrode length: 50 mm, electrode spacing: 50 mm) is used to ground the electrodes to the surface of the object to be measured, and a voltage of 100 V is applied and the resistance value is measured to measure the surface resistance (Ω / sq.) of each layer. The surface resistance (Ω / sq.) of the substrate layer 2 described later can be measured by itself. The specific measurement method can be the method described in the Examples.

[0019] In addition, the surface resistance of the surface of the decorative sheet of the present disclosure on the side of the surface protective layer is preferably 10 11 Ω / sq. or more, preferably 10 13 The surface resistance of the surface of the decorative sheet of the present disclosure opposite to the surface protective layer side (for example, the substrate layer side in the case where a substrate layer is provided) is preferably 10 11 Ω / sq. or more, preferably 10 13The surface resistance is Ω / sq. or more. The surface resistance (Ω / sq.) is measured for the surface protective layer side and the surface base layer side of the decorative sheet using a commercially available surface resistance measuring device. The specific measurement of the surface resistance is performed according to the method described in the Examples.

[0020] Each layer that makes up the decorative sheet [Surface protection layer 1] The surface protective layer 1 is a layer provided to protect the surface of the decorated resin molded article.

[0021] The surface resistance of all layers included in the decorative sheet of the present disclosure is 10 11 That is, the surface resistance of the surface protective layer 1 is also 10 11 As described above, the surface resistance of the surface protective layer 1 is preferably 10 13 Ω / sq. or more.

[0022] The material constituting the surface protective layer 1 is not particularly limited as long as it satisfies the above-mentioned surface resistance value, and examples thereof include thermoplastic resins, thermosetting resins, ionizing radiation curable resins, etc. Among these, from the viewpoint of suitably imparting the function of a surface protective layer to the decorated resin molded product, it is preferable that the surface protective layer 1 is composed of a cured product of an ionizing radiation curable resin composition. The ionizing radiation curable resin used to form the surface protective layer 1 will be described in detail below.

[0023] (ionizing radiation curable resin) The ionizing radiation curable resin used in the formation of the surface protective layer 1 is a resin that is crosslinked and cured by irradiation with ionizing radiation, and specifically includes a suitable mixture of at least one of prepolymers, oligomers, and monomers having polymerizable unsaturated bonds or epoxy groups in the molecule. Here, the ionizing radiation means electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules, and usually ultraviolet rays (UV) or electron beams (EB) are used, but also includes electromagnetic waves such as X-rays and γ-rays, α-rays, ion beams, and other charged particle beams. Among the ionizing radiation curable resins, electron beam curable resins are suitable for use in the formation of the surface protective layer 1 because they can be made solvent-free, do not require a photopolymerization initiator, and have stable curing properties.

[0024] The monomer used as the ionizing radiation curable resin is preferably a (meth)acrylate monomer having a radical polymerizable unsaturated group in the molecule, and among them, a polyfunctional (meth)acrylate monomer is preferable. The polyfunctional (meth)acrylate monomer may be a (meth)acrylate monomer having two or more (bifunctional or more), preferably three or more (trifunctional or more), polymerizable unsaturated bonds in the molecule. Specific examples of the polyfunctional (meth)acrylate include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, trimethylol propionate, and the like. Examples of the monomer include propane 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 hexa(meth)acrylate, etc. These monomers may be used alone or in combination of two or more.

[0025] As the oligomer used as the ionizing radiation curable resin, a (meth)acrylate oligomer having a radical polymerizable unsaturated group in the molecule is preferable, and among them, a polyfunctional (meth)acrylate oligomer having two or more (two or more functional) polymerizable unsaturated bonds in the molecule is preferable. Examples of the polyfunctional (meth)acrylate oligomer include polycarbonate (meth)acrylate, acrylic silicone (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, polybutadiene (meth)acrylate, silicone (meth)acrylate, and oligomers having a cationic polymerizable functional group in the molecule (e.g., novolac type epoxy resin, bisphenol type epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc.). Here, the polycarbonate (meth)acrylate is not particularly limited as long as it has a carbonate bond in the polymer main chain and a (meth)acrylate group at the end or side chain, and can be obtained, for example, by esterifying a polycarbonate polyol with (meth)acrylic acid. The polycarbonate (meth)acrylate may be, for example, a urethane (meth)acrylate having a polycarbonate skeleton. The urethane (meth)acrylate having a polycarbonate skeleton can be obtained, for example, by reacting a polycarbonate polyol with a polyvalent isocyanate compound and a hydroxy (meth)acrylate. The acrylic silicone (meth)acrylate can be obtained by radical copolymerization of a silicone macromonomer with a (meth)acrylate monomer. The urethane (meth)acrylate can be obtained, for example, by esterifying a polyurethane oligomer obtained by the reaction of a polyether polyol or a polyester polyol with a polyisocyanate compound with (meth)acrylic acid. Epoxy (meth)acrylates can be obtained, for example, by reacting an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolac type epoxy resin with (meth)acrylic acid to effect esterification.In addition, a carboxyl-modified epoxy (meth)acrylate obtained by partially modifying this epoxy (meth)acrylate with a dibasic carboxylic anhydride can also be used. The polyester (meth)acrylate can be obtained, for example, by esterifying the hydroxyl group of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth)acrylic acid, or by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid with (meth)acrylic acid. The polyether (meth)acrylate can be obtained by esterifying the hydroxyl group of a polyether polyol with (meth)acrylic acid. The polybutadiene (meth)acrylate can be obtained by adding (meth)acrylic acid to the side chain of a polybutadiene oligomer. The silicone (meth)acrylate can be obtained by adding (meth)acrylic acid to the end or side chain of a silicone having a polysiloxane bond in the main chain. These oligomers may be used alone or in combination of two or more.

[0026] Among the above-mentioned ionizing radiation curable resins, it is preferable to use polycarbonate (meth)acrylate from the viewpoint of obtaining excellent three-dimensional moldability while further improving the appearance design, wear resistance and moldability. It is also preferable to use a combination of polycarbonate (meth)acrylate and urethane (meth)acrylate.

[0027] The surface protective layer 1 may contain at least one of inorganic particles and organic particles. In the surface protective layer 1, the inorganic particles and organic particles mainly have the function of reducing the gloss of the surface protective layer 1. When the surface protective layer 1 contains inorganic particles or organic particles, these particles are dispersed in the surface protective layer 1.

[0028] The inorganic particles are not particularly limited as long as they are particles formed by an inorganic compound, and examples thereof include silica particles, calcium carbonate particles, barium sulfate particles, alumina particles, and glass balloon particles. The inorganic particles may be used alone or in combination of two or more types. The particle diameter of the inorganic particles is, for example, about 0.5 μm or more, preferably about 1 μm or more, and preferably about 20 μm or less, more preferably about 10 μm or less. The preferred ranges of the particle diameter of the inorganic particles include about 0.5 to 20 μm, about 0.5 to 10 μm, about 1 to 20 μm, and about 1 to 10 μm. In the present invention, the particle diameter of the inorganic particles is a value measured by a spray-type dry measurement method using a commercially available laser diffraction particle size distribution measuring device, in which the powder to be measured is sprayed from a nozzle using compressed air, dispersed in the air, and measured.

[0029] When the surface protective layer 1 contains inorganic particles, the content of the inorganic particles is not particularly limited, but is preferably about 1 part by mass or more, more preferably about 10 parts by mass or more, and is also preferably about 60 parts by mass or less, more preferably about 40 parts by mass or less, relative to 100 parts by mass of the above-mentioned ionizing radiation curable resin. Preferred ranges of the content of the inorganic particles include about 1 to 60 parts by mass, about 1 to 40 parts by mass, about 10 to 60 parts by mass, and about 10 to 40 parts by mass, relative to 100 parts by mass of the above-mentioned ionizing radiation curable resin. One type of inorganic particles may be used alone, or two or more types may be used in combination.

[0030] In addition, the organic particles are not particularly limited as long as they are particles formed from a resin, and examples thereof include urethane beads, nylon beads, acrylic beads, silicone beads, styrene beads, melamine beads, urethane acrylic beads, polyester beads, and polyethylene beads. The organic particles may be used alone or in combination of two or more types. The particle diameter of the organic particles is about 0.5 μm or more, preferably about 1 μm or more, and is preferably about 30 μm or less, more preferably about 20 μm or less. The preferred particle diameter ranges of the organic particles include about 0.5 to 30 μm, about 0.5 to 20 μm, about 1 to 30 μm, and about 1 to 20 μm. The particle diameter of the organic particles is a value measured by the same method as that of the inorganic particles.

[0031] When the surface protective layer 1 contains organic particles, the content of the organic particles is not particularly limited, but is preferably about 1 part by mass or more, more preferably about 10 parts by mass or more, and is preferably about 200 parts by mass or less, more preferably 150 parts by mass or less, relative to 100 parts by mass of the above-mentioned ionizing radiation curable resin. Preferred ranges for the content of the organic particles include about 1 to 200 parts by mass, about 1 to 150 parts by mass, about 10 to 200 parts by mass, and more preferably about 10 to 150 parts by mass, relative to 100 parts by mass of the above-mentioned ionizing radiation curable resin.

[0032] In addition, when the surface protective layer 1 contains at least one of inorganic particles and organic particles, some of these particles may protrude from the surface of the surface protective layer 1, or the particles may be buried inside the surface protective layer 1.

[0033] (Other added ingredients) Various additives can be blended into the surface protective layer 1 depending on the desired physical properties to be provided to the surface protective layer 1. Examples of the additives include weather resistance improvers such as ultraviolet absorbers and light stabilizers, abrasion resistance improvers, polymerization inhibitors, crosslinking agents, infrared absorbers, adhesion improvers, leveling agents, thixotropy imparting agents, coupling agents, plasticizers, defoamers, fillers, solvents, colorants, and the like. These additives can be appropriately selected from those commonly used. In addition, reactive ultraviolet absorbers and light stabilizers having a polymerizable group such as a (meth)acryloyl group in the molecule can also be used as the ultraviolet absorbers and light stabilizers.

[0034] (Formation of Surface Protection Layer 1) The surface protective layer 1 is formed, for example, by preparing an ionizing radiation curable resin composition containing an ionizing radiation curable resin (containing the above-mentioned inorganic particles, organic particles, various additives, etc., as necessary), applying the composition, and curing it. The viscosity of the ionizing radiation curable resin composition may be any viscosity that allows the formation of an uncured resin layer by the application method described below.

[0035] In the present disclosure, the prepared resin composition is applied by a known method such as gravure coating, bar coating, roll coating, reverse roll coating, or comma coating, preferably gravure coating, to form an uncured resin layer.

[0036] The uncured resin layer thus formed is irradiated with ionizing radiation such as electron beams or ultraviolet rays to cure the uncured resin layer, thereby forming the surface protective layer 1. When an electron beam is used as the ionizing radiation, the acceleration voltage can be appropriately selected depending on the resin used and the thickness of the layer, but typically, the acceleration voltage is 70 kV or more and 300 kV or less. The preferred range of the acceleration voltage is 70 to 300 kV.

[0037] In electron beam irradiation, the higher the acceleration voltage, the greater the penetration ability, so when a resin that is easily deteriorated by electron beam irradiation is used under the surface protective layer 1, the acceleration voltage is selected so that the penetration depth of the electron beam is substantially equal to the thickness of the surface protective layer 1. This makes it possible to prevent excess irradiation of the electron beam to the layer located under the surface protective layer 1, and minimizes the deterioration of each layer due to excess electron beams.

[0038] The exposure dose is preferably an amount at which the crosslink density of the surface protective layer 1 is saturated, and is usually 5 kGy or more (0.5 Mrad or more), preferably 10 kGy or more (1 Mrad or more), and usually 300 kGy or less (30 Mrad or less), preferably 50 kGy or less (5 Mrad or less). The exposure dose is preferably selected from the ranges of 5 to 300 kGy (0.5 to 30 Mrad), 5 to 50 kGy (0.5 to 5 Mrad), 10 to 300 kGy (1 to 30 Mrad), or 10 to 50 kGy (1 to 5 Mrad).

[0039] Furthermore, the electron beam source is not particularly limited, and various electron beam accelerators such as Cockcroft-Walton type, Van de Graft type, resonant transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type can be used.

[0040] When ultraviolet light is used as the ionizing radiation, light rays containing ultraviolet light having a wavelength of 190 to 380 nm may be emitted. The source of ultraviolet light is not particularly limited, but examples thereof include high pressure mercury lamps, low pressure mercury lamps, metal halide lamps, and carbon arc lamps.

[0041] The surface protective layer 1 thus formed may be treated by adding various additives to impart functions such as a hard coat function, an anti-fogging coat function, an anti-fouling coat function, an anti-glare coat function, an anti-reflection coat function, an ultraviolet shielding coat function, and an infrared shielding coat function.

[0042] [Base material layer 2] The base layer 2 is a layer that is provided as necessary in the decorative sheet of the present disclosure, and is a resin sheet (resin film) that serves as a support.

[0043] As described above, the surface resistance of all layers included in the decorative sheet of the present disclosure is 10 11 Ω / sq. or more, the surface resistance of the base layer 2 is also 10 11 The surface resistance of the substrate layer 2 is preferably 10 13 Ω / sq. or more.

[0044] The resin component used in the base layer 2 is not particularly limited as long as it satisfies the above-mentioned surface resistance value, and may be appropriately selected depending on the three-dimensional moldability and compatibility with the molded resin, but preferably includes a resin film made of a thermoplastic resin. Specific examples of the thermoplastic resin include acrylonitrile-butadiene-styrene resin (hereinafter sometimes referred to as "ABS resin"), acrylonitrile-styrene-acrylic acid ester resin (hereinafter sometimes referred to as "ASA resin"), acrylic resin, polyolefin resin such as polypropylene and polyethylene, polycarbonate resin, vinyl chloride resin, polyethylene terephthalate (PET), etc. Among these, ABS resin and acrylic resin are preferable from the viewpoint of three-dimensional moldability. In addition, the base layer 2 may be formed of a single-layer sheet of these resins, or may be formed of a multi-layer sheet of the same or different resins.

[0045] The softening point of the thermoplastic resin is preferably about 80 to 155°C, more preferably about 90 to 140°C, and further preferably about 105 to 125°C.

[0046] The flexural modulus of the base layer 2 is not particularly limited. For example, when the decorative sheet of the present disclosure is integrated with a molding resin by an insert molding method, the flexural modulus of the base layer 2 in the decorative sheet of the present disclosure at 25°C is 500 to 4,000 MPa, preferably 750 to 3,000 MPa. Here, the flexural modulus at 25°C is a value measured in accordance with JIS K7171. When the flexural modulus at 25°C is 500 MPa or more, the decorative sheet has sufficient rigidity, and even when subjected to an insert molding method, the surface characteristics and moldability become even better. In addition, when the flexural modulus at 25°C is 3,000 MPa or less, sufficient tension can be applied when manufactured by roll-to-roll, and sagging is unlikely to occur, so that the pattern can be printed over without shifting, and so-called pattern registration becomes good.

[0047] In order to improve adhesion to a layer provided thereon, the substrate layer 2 may be subjected to a physical or chemical surface treatment such as an oxidation method or a roughening method on one or both sides as necessary. Examples of the oxidation method used as the surface treatment of the substrate layer 2 include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, and ozone ultraviolet treatment. Examples of the roughening method used as the surface treatment of the substrate layer 2 include sandblasting and solvent treatment. These surface treatments are appropriately selected depending on the type of resin component constituting the substrate layer 2, but from the viewpoints of effect and operability, a corona discharge treatment is preferably used.

[0048] Furthermore, the base layer 2 may be subjected to a known treatment such as forming an adhesive layer.

[0049] Furthermore, the base layer 2 may be colored with a colorant, or may not be colored, as long as the surface resistance value is satisfied. The base layer 2 may be colorless and transparent, colored and transparent, or translucent. The colorant used in the base layer 2 is not particularly limited, but preferably is a colorant that does not discolor even at temperatures of 150° C. or higher, and specifically includes existing dry colors, paste colors, masterbatch resin compositions, and the like.

[0050] The thickness of the base layer 2 is appropriately set depending on the application of the decorative sheet, the molding method for integrating it with a molding resin, etc., but is usually about 25 to 1000 μm, or about 50 to 700 μm. More specifically, when the decorative sheet of the present disclosure is subjected to an insert molding method, the thickness of the base layer 2 is usually about 50 to 1000 μm, preferably about 100 to 700 μm, and more preferably about 100 to 500 μm.

[0051] [Primer layer 3] The primer layer 3 is a layer that is provided, if necessary, so as to come into contact with the surface of the surface protective layer 2 (the side opposite the side on which the decorative sheet or decorated resin molded product is observed, for example, the surface on the side of the base layer 2 in the case where the base layer 2 is present) for the purpose of increasing adhesion between the surface protective layer 2 and the layer located below it.

[0052] As described above, the surface resistance of all layers included in the decorative sheet of the present disclosure is 10 11 Ω / sq. or more, the surface resistance of the primer layer 3 is also 10 11 The surface resistance of the primer layer 3 is preferably 10 13 Ω / sq. or more.

[0053] The primer composition constituting the primer layer 3 is not particularly limited as long as it satisfies the above-mentioned surface resistance value, and preferably uses a binder resin such as urethane resin, (meth)acrylic resin, (meth)acrylic-urethane copolymer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, butyral resin, chlorinated polypropylene, chlorinated polyethylene, etc., and these resins can be used alone or in combination of two or more. Among these, urethane resin, (meth)acrylic resin, and (meth)acrylic-urethane copolymer resin are preferred.

[0054] As the urethane resin, polyurethane containing polyol (polyhydric alcohol) as a main component and isocyanate as a crosslinking agent (curing agent) can be used. As the polyol, one having two or more hydroxyl groups in the molecule, such as polyester polyol, polyethylene glycol, polypropylene glycol, acrylic polyol, polyether polyol, etc. can be used. As the isocyanate, a polyvalent isocyanate having two or more isocyanate groups in the molecule, an aromatic isocyanate such as 4,4-diphenylmethane diisocyanate, or an aliphatic (or alicyclic) isocyanate such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, etc. can also be used to form the resin by mixing the urethane resin and the butyral resin.

[0055] In terms of adhesion to the surface protective layer 2 after crosslinking, the likelihood of interactions occurring after lamination of the surface protective layer 2, physical properties, and moldability, it is preferable to combine an acrylic polyol or a polyester polyol as the polyol with hexamethylene diisocyanate or 4,4-diphenylmethane diisocyanate as the crosslinking agent, and it is particularly preferable to use a combination of an acrylic polyol and hexamethylene diisocyanate.

[0056] Examples of the (meth)acrylic resin include a homopolymer of a (meth)acrylic acid ester, a copolymer of two or more different (meth)acrylic acid ester monomers, or a copolymer of a (meth)acrylic acid ester and another monomer. Specifically, (meth)acrylic resins consisting of a homopolymer or copolymer containing a (meth)acrylic acid ester, such as polymethyl(meth)acrylate, polyethyl(meth)acrylate, polypropyl(meth)acrylate, polybutyl(meth)acrylate, a methyl(meth)acrylate-butyl(meth)acrylate copolymer, an ethyl(meth)acrylate-butyl(meth)acrylate copolymer, an ethylene-methyl(meth)acrylate copolymer, or a styrene-methyl(meth)acrylate copolymer, are preferably used.

[0057] As the (meth)acrylic-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. As the acrylic-urethane (polyester urethane) block copolymer resin, if desired, the acrylic / urethane ratio (mass ratio) is preferably 1 / 9 or more, more preferably 2 / 8 or more. In addition, the acrylic / urethane ratio (mass ratio) is preferably 9 / 1 or less, more preferably 8 / 2 or less.

[0058] The thickness of the primer layer 3 is not particularly limited, but is, for example, 0.5 μm or more, preferably 1 μm or more, and preferably 20 μm or less, more preferably 5 μm or less, and preferred ranges include about 0.5 to 20 μm, and about 1 to 5 μm.

[0059] The primer layer 3 is formed using a primer composition by a normal coating method such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating, kiss coating, wheeler coating, dip coating, solid coating by silk screen, wire bar coating, flow coating, comma coating, pouring coating, brush coating, spray coating, or transfer coating. Here, the transfer coating method is a method in which a coating film of the primer layer 3 is formed on a thin sheet (film substrate), and then the surface of the target layer in the decorative sheet is coated with the primer layer 3.

[0060] [Decorative layer 4] The decorative layer 4 is a layer that is provided as necessary, for example, between the base material layer 2 and the surface protective layer 2, or between the base material layer 2 and the primer layer 3 if a primer layer 3 is provided, for the purpose of imparting decorativeness to the decorative sheet.

[0061] As described above, the surface resistance of all layers included in the decorative sheet of the present disclosure is 10 11 Since the surface resistance of the decorative layer 4 is 10 11 The surface resistance of the decorative layer 4 is preferably 1013 Ω / sq. or more.

[0062] Examples of the decorative layer 4 include a picture layer having a picture, and a concealing layer (base layer) having no picture and intended to suppress color change or variation in the base layer 2. Even when the decorative layer 4 includes a picture layer and a concealing layer, the decorative layer 4 as a whole needs to satisfy the above-mentioned surface resistance value. For this reason, in the decorative sheet of the present disclosure, the picture layer and the concealing layer also satisfy the above-mentioned surface resistance value.

[0063] The decorative layer 4 can be, for example, a layer (ink layer) on which a desired pattern is formed using an ink composition. The ink composition used to form the decorative layer 4 is a suitable mixture of a binder, a colorant such as a pigment or dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent, and the like.

[0064] The binder used in the ink composition is not particularly limited, and examples thereof include polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-acrylic copolymer resin, chlorinated polypropylene resin, acrylic resin, polyester resin, polyamide resin, butyral resin, polystyrene resin, nitrocellulose resin, cellulose acetate resin, etc. These binders may be used alone or in combination of two or more.

[0065] The colorant used in the ink composition is not particularly limited as long as the decorative layer 4 satisfies the above-mentioned surface resistance value, but examples thereof include inorganic pigments such as carbon black (ink), iron black, titanium white, antimony white, yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue; organic pigments or dyes such as quinacridone red, isoindolinone yellow, and phthalocyanine blue; metal pigments made of scaly foil flakes such as aluminum and brass; and pearlescent (pearl) pigments made of scaly foil flakes such as titanium dioxide-coated mica and basic lead carbonate. In the decorative sheet of the present disclosure, the decorative layer 4 preferably contains at least one of a carbon pigment and an aluminum pigment.

[0066] The pattern formed by the decorative layer 4 is not particularly limited, and examples thereof include a wood grain pattern, a marble pattern (e.g., travertine marble pattern) or other stone pattern that imitates the surface of rocks, a fabric pattern that imitates a cloth or cloth-like pattern, a tiled pattern, a brickwork pattern, etc., and may also be a combination of these patterns such as marquetry or patchwork, or may be a single plain color (so-called solid color on the entire surface). These patterns are formed by multi-color printing using the usual process colors of yellow, red, blue, and black, but can also be formed by multi-color printing using special colors that are performed by preparing plates of the individual colors that make up the pattern.

[0067] The thickness of the decorative layer 4 is not particularly limited, but is, for example, 1 to 30 μm, and preferably 1 to 20 μm.

[0068] [Hidden layer] In the decorative layer 4, the concealing layer (base layer) is a layer that is provided as necessary between the substrate layer 2 and the surface protective layer 2, between the substrate layer 2 and the primer layer 3 if a primer layer 3 is provided, or between the substrate layer 2 and the pattern layer if a pattern layer is provided in the decorative layer 4, for the purpose of suppressing color changes or variations in the substrate layer 2.

[0069] The concealing layer is provided to prevent the base layer from adversely affecting the color tone and pattern of the decorative sheet, and is therefore generally formed as a layer of an opaque color.

[0070] The concealing layer is formed using an ink composition in which a binder is appropriately mixed with a colorant such as a pigment or a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a hardener, etc. The ink composition for forming the concealing layer is appropriately selected from those used for the decorative layer described above.

[0071] The concealing layer is usually set to a thickness of about 1 to 20 μm, and is desirably formed as a so-called solid print layer.

[0072] The concealing layer is formed by a conventional printing method such as gravure printing, offset printing, silk screen printing, printing by transfer from a transfer sheet, inkjet printing, etc.; or a conventional coating method such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating, etc.

[0073] [Back adhesive layer] The back surface adhesive layer (not shown) is a layer that is provided, if necessary, on the back surface of the base material layer 2 (the surface opposite to the surface protective layer 2) for the purpose of increasing adhesion with the molding resin when molding a decorated resin molded product.

[0074] The back surface adhesive layer is made of a thermoplastic resin or a curable resin depending on the molding resin used in the decorated resin molded product.

[0075] Examples of thermoplastic resins used to form the back surface adhesive layer include acrylic resins, acrylic-modified polyolefin resins, chlorinated polyolefin resins, vinyl chloride / vinyl acetate copolymers, thermoplastic urethane resins, thermoplastic polyester resins, polyamide resins, rubber-based resins, etc. These thermoplastic resins may be used alone or in combination of two or more.

[0076] Examples of the thermosetting resin used to form the back surface adhesive layer include urethane resin, epoxy resin, etc. These thermosetting resins may be used alone or in combination of two or more.

[0077] 2. Decorative resin moldings The decorated resin molded product of the present disclosure is formed by integrating a molded resin layer 5 with the decorative sheet 10 of the present disclosure.

[0078] More specifically, as shown in FIG. 4, the decorated resin molded product 20 of the present disclosure is a decorated resin molded product in which the decorative sheet of the present disclosure is laminated on the molded resin layer 5, and the surface resistance value of all layers included in the decorative sheet is 10 11That is, the decorated resin molded product 20 of the present disclosure is a decorated resin molded product including at least a molded resin layer 5 and a surface protective layer 1, and the surface resistance of all layers (including the surface protective layer 1) on the surface protective layer 1 side of the molded resin layer 5 is 10 11 It is characterized by a resistance of Ω / sq. or more.

[0079] Fig. 4 shows a cross-sectional structure of one embodiment of the decorated resin molded product of the present disclosure. Fig. 4 is a schematic cross-sectional view of a decorated resin molded product 20 in which the decorative sheet 10 having the laminated structure shown in Fig. 3 and the molded resin layer 5 are integrated together.

[0080] The decorated resin molded product 20 of the present disclosure can be manufactured by a method including a step of forming a molded resin layer 5 by injecting a resin into the decorative sheet 10 of the present disclosure. Specifically, the manufacturing method of the decorated resin molded product of the present disclosure includes a step of statically charging the decorative sheet of the present disclosure and fixing the decorative sheet to a mold, and a step of integrating the decorative sheet 10 and the molded resin layer 5 by injecting a resin into the mold.

[0081] As a molding method for integrating the decorative sheet of the present disclosure with the molded resin layer, various injection molding methods such as insert molding, blow molding, and gas injection molding can be used.

[0082] In the insert molding method, first, in a vacuum forming process, the decorative sheet of the present disclosure is vacuum-formed in advance into the surface shape of the molded product (offline preforming) using a vacuum forming mold, and then excess parts are trimmed as necessary to obtain a molded sheet. This molded sheet is inserted into an injection mold, the injection mold is closed, and a resin in a fluid state is injected into the mold and solidified, and the decorative sheet is integrated with the outer surface of the resin molded product at the same time as injection molding, thereby producing a decorated resin molded product.

[0083] More specifically, the decorated resin molded product of the present disclosure is produced by an insert molding method including the following steps.

[0084] A vacuum forming process in which the decorative sheet of the present disclosure is formed into a three-dimensional shape in advance using a vacuum forming mold; A step of trimming an excess portion of the vacuum-formed decorative sheet to obtain a formed sheet; and The molded sheet obtained in the previous step is inserted into an injection mold, the mold is closed, and the resin in a fluid state is injected into the mold to integrate the resin and the molded sheet. In this step, the decorative sheet can be charged with static electricity to fix it to the injection mold.

[0085] In the vacuum forming step in the insert molding method, the decorative sheet may be heated and molded. The heating temperature is not particularly limited and may be appropriately selected depending on the type of resin constituting the decorative sheet and the thickness of the decorative sheet, but for example, when an ABS resin film is used as the base layer, the heating temperature is usually about 100 to 250°C, preferably about 130 to 200°C. In the integration step, the temperature of the resin in a fluid state is not particularly limited, but may usually be about 180 to 320°C, preferably about 220 to 280°C.

[0086] In the decorated resin molded product of the present disclosure, the molded resin layer may be formed by selecting a molding resin according to the application. The molding resin may be a thermoplastic resin or a thermosetting resin.

[0087] Examples of thermoplastic resins used as molding resins include polyolefin resins such as polyethylene and polypropylene, ABS resins, styrene resins, polycarbonate resins, acrylic resins, vinyl chloride resins, etc. These thermoplastic resins may be used alone or in combination of two or more.

[0088] Examples of the thermosetting resin used as the molding resin include urethane resin, epoxy resin, etc. These thermosetting resins may be used alone or in combination of two or more.

[0089] The decorated resin molded product of the present disclosure has an excellent design and can be used, for example, as interior or exterior materials for vehicles such as automobiles; construction components such as baseboards and moldings; window frames, door frames and other fittings; interior materials for buildings such as walls, floors and ceilings; housings for home appliances such as television sets and air conditioners; containers, etc. EXAMPLES

[0090] The present disclosure will be described in detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the examples.

[0091] <Examples 1 to 10 and Comparative Examples 1 to 4> (Manufacture of decorative sheets) A decorative layer was formed by gravure coating on the surface of an ABS resin film (thickness 480 μm) as a base layer. The decorative layer was made up of an undercoat layer (thickness about 1 μm) and an ink layer (thickness about 1 μm) in this order from the base layer side. In Examples 1 to 4 and Comparative Examples 1 to 3, a black ink layer was formed using black ink (containing carbon pigment), and in Examples 5 to 10 and Comparative Example 4, a silver ink layer was formed using silver ink (containing aluminum pigment). Next, a primer layer (thickness 3 μm) made of an acrylic resin (a homopolymer of acrylic acid ester) was applied to the surface of the decorative layer by gravure coating. Next, an electron beam curable resin composition (bifunctional polycarbonate acrylate, weight average molecular weight: 10,000) was applied to the surface of the primer layer by gravure coating so as to have a thickness of 10 μm after curing. This uncured resin layer was irradiated with an electron beam at an acceleration voltage of 165 kV and an exposure dose of 50 kGy (5 Mrad) to cure the electron beam curable resin composition, forming a surface protective layer, and each decorative sheet was obtained.

[0092] In Examples 1 to 4 and Comparative Examples 1 to 3, the black ink layer was formed using an acrylic / vinyl chloride acetate gravure ink containing 43% carbon black in the solid content as the black ink, and an acrylic / vinyl chloride acetate gravure ink containing no pigments such as carbon black or dyes as the medium, with the carbon pigment concentration in the black ink layer adjusted to the value in Table 1. In Examples 5 to 10 and Comparative Example 4, the silver ink layers were formed using a silver ink (acrylic / vinyl chloride acetate gravure ink containing aluminum pigment) and a medium (acrylic / vinyl chloride acetate gravure ink containing no pigment or dye), with the aluminum pigment concentration in the silver ink layer adjusted to the value in Table 2.

[0093] (Measurement of surface resistance) The surface resistance (Ω / sq.) of the surface protective layer side and the surface of the base layer side of the decorative sheet was measured using a surface resistance measuring device (ST-14; manufactured by Simco Japan Co., Ltd.). In addition, the surface resistance of the decorative layer (ink layer and undercoat layer), primer layer, and surface protective layer of the decorative sheet was measured by preparing samples of these layers formed on a 50 μm thick PET film, and measuring the surface resistance (Ω / sq.) from the surface of each layer. The surface resistance (Ω / sq.) of the base layer was measured alone. The results are shown in Tables 1 and 2.

[0094] [Evaluation of decorative sheets] (Electrostatic property) The decorative sheet was cut to A4 size to prepare a sample. The sample was placed on a grounded metal stand. The sample was charged using a simple charging device, and after leaving it to stand for 30 seconds, the charge amount (kV) was measured. The simple charging device used was a battery-powered charging gun, negative polarity type GC25B (Green Techno 21 Co., Ltd.), and the voltage measuring device used was a static potential meter KSD-2000 (Kasuga Denki). The results are shown in Tables 1 and 2.

[0095] (Charge retention) The decorative sheet was cut to A4 size to prepare a sample. The sample was placed on a grounded metal stand. The sample was charged with a simple charging device and quickly attached to a grounded vertical metal wall, and the state in which the sample fell under its own weight was observed. A battery-powered charging gun, negative polarity type GC25B (Green Techno 21 Co., Ltd.) was used as the simple charging device. The results are shown in Tables 1 and 2.

[0096] [Table 1]

[0097] [Table 2] [Explanation of symbols]

[0098] 1 Base material layer 2 Surface protective layer 3 Primer layer 4 Decorative layer 5 Molding resin layer 10 Decorative sheet 20 Decorative resin moldings

Claims

1. A decorative sheet used in an insert molding method for manufacturing decorative resin molded products, which is fixed to a mold by electrostatic charging, At a minimum, it is equipped with a surface protective layer, The surface resistance value of all layers included in the decorative sheet is 10 11 The decorative sheet has a value of Ω / sq. or higher.

2. The decorative sheet according to claim 1, wherein the decorative sheet further comprises a decorative layer.

3. The decorative sheet according to claim 2, wherein the decorative layer comprises at least one of a carbon pigment and an aluminum pigment.

4. The decorative sheet according to claim 2 or 3, wherein the decorative sheet is composed of a laminate comprising, at least, a base layer, the decorative layer, a primer layer, and the surface protective layer in that order.

5. A decorative resin molded product comprising a decorative sheet according to any one of claims 1 to 3 laminated on a molded resin layer, The surface resistance value of all layers included in the decorative sheet is 10 11 A decorative resin molded product with a density of Ω / sq. or greater.

6. A step of electrostatically charging a decorative sheet according to any one of claims 1 to 3 and fixing the decorative sheet to a mold, The process involves injecting resin into the mold to integrate the decorative sheet and the molded resin layer, A method for manufacturing a decorative resin molded product, comprising the following features.

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