Method for manufacturing decorative sheet and decorative molded product

Abstract

To suppress the breakage of an image layer in response to foaming of a foamable layer of a decorative sheet.SOLUTION: A method for manufacturing a decorative molded article comprises steps of: heating a foamable layer transfer sheet provided with a foamable layer that contains foamable particles to transfer the foamable layer to a predetermined area of one surface of a base material; forming an image layer on the other surface of the base material; bonding a foamable layer side of the decorative sheet laminated with the image layer, the base materia, and the foamable layer, and the molded article via an adhesive layer; and foaming the foamable layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Out-molding is known as one method of decorating three-dimensional molded products. Out-molding allows patterns to be added later, making it possible to produce a wide variety of products in small lots to meet diversifying consumer needs. In addition, out-molding has a lower environmental impact than printing, so it has been increasingly adopted in recent years.

[0003] Out-molding is a molding method that uses stretchable film, but gravure printing is mainly used for printing patterns. As mentioned above, out-molding is a molding method suited to small-lot, high-mix production, while gravure printing is a method suited to mass production, so depending on the quantity, it may not be profitable. Digital printing such as inkjet printing is considered a printing method suited to small-lot, high-mix production. Some inkjet printers use UV to harden the ink, and while it is possible to create textures such as unevenness, it is not suitable for creating an elastic feel like leather.

[0004] A known method for achieving an elastic feel is to use foam particles. For example, Patent Document 1 discloses a method in which a thermally foamable ink is applied to a vacuum-formable thermoplastic sheet, a transfer film is then laminated on the applied surface so that the patterned ink side of the transfer film overlaps the applied surface, and the thermally foamable ink is foamed by heating, while the thermoplastic sheet is vacuum-formed at the same time.

[0005] However, in the method described in Patent Document 1, since the thermally foamable ink is applied to a thermoplastic sheet, it is only possible to form a foamable ink layer of uniform thickness over the entire surface, and it is difficult to form a foamable ink layer partially.

[0006] Furthermore, when a transfer film is laminated on the foamable ink layer so that the pattern ink surface overlaps the foamable ink layer, a step occurs in the transfer film between the part laminated on the foamable ink layer and the part laminated on the thermoplastic sheet. When the foamable ink layer is foamed, the step in the transfer film becomes large, and the transfer film breaks at the boundary between the part with the foamable ink layer and the part without it, becoming discontinuous and causing the problem of floating. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 5-254238 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present disclosure is to provide a decorative sheet and a method for manufacturing a decorated molded product that can suppress breakage of an image layer due to foaming of the foam layer. [Means for solving the problem]

[0009] The method for manufacturing a decorated molded product of the present disclosure includes the steps of heating a foam layer transfer sheet having a foam layer containing foam particles and transferring the foam layer to a predetermined area on one side of a substrate, forming an image layer on the other side of the substrate, bonding the foam layer side of the decorative sheet having the image layer, the substrate, and the foam layer laminated together to a molded product via an adhesive layer, and foaming the foam layer.

[0010] The decorative sheet of the present disclosure comprises a substrate, a foam layer provided in a predetermined region on one surface of the substrate, an adhesive layer provided on one surface of the substrate so as to cover the foam layer, and an image layer provided on the other surface of the substrate. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to suppress breakage of the image layer due to foaming of the foam layer. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a cross-sectional view of a foam layer transfer sheet. [Figure 2] 10A to 10C are cross-sectional views illustrating a method for manufacturing a decorative sheet. [Figure 3] 10A to 10C are cross-sectional views illustrating a method for manufacturing a decorative sheet. [Figure 4] 10A to 10C are cross-sectional views illustrating a method for manufacturing a decorative sheet. [Figure 5] FIG. 10 is a cross-sectional view illustrating a decorative molding step. [Figure 6] FIG. 10 is a cross-sectional view illustrating a decorative molding step. [Figure 7] FIG. 10 is a cross-sectional view of a decorated molded product according to a comparative example. [Figure 8] 10A to 10C are cross-sectional views illustrating a method for manufacturing a decorative sheet according to another embodiment. [Figure 9] FIG. 2 is a cross-sectional view of a decorated molded product. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. To clarify the description, the drawings may show the width, thickness, etc. of each part more schematically than in the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present disclosure. In the present specification and drawings, elements similar to those previously described with reference to the preceding drawings are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0014] A method for manufacturing a decorated molded product according to an embodiment of the present disclosure involves preparing a decorative sheet having a foam layer, attaching this decorative sheet to a molded product using a technique such as out-mold molding, in-mold molding, or insert molding, and foaming the foam layer.

[0015] A method for manufacturing a decorative sheet will now be described. Fig. 1 is a cross-sectional view of a foam layer transfer sheet 10 for transferring a foam layer onto the substrate of a decorative sheet. The foam layer transfer sheet 10 has a substrate 11 and a foam layer 12 provided on one surface of the substrate 11.

[0016] The foam layer 12 includes foam particles. The foam particles have an outer shell made of a thermoplastic resin and a foaming agent encapsulated in the outer shell that vaporizes when heated. Therefore, the foam particles expand when heated.

[0017] A back layer (not shown) may be provided on the other surface of the substrate 11. A release layer (not shown) may be provided between the foam layer 12 and the substrate 11. An adhesive layer (not shown) may be provided on the foam layer 12.

[0018] As shown in FIG. 2, an image layer 2 is formed on one surface of a base material 1 of a decorative sheet using a known thermal transfer printer.

[0019] When the decorative molding process described below is out-mold molding, the material of the substrate 1 of the decorative sheet is preferably PVC (polyvinyl chloride), PETG (glycol-modified polyethylene terephthalate), PO (polyolefin), PU (polyurethane), TPU (polyurethane thermoplastic elastomer), etc. When the decorative molding process is in-mold molding, the material of the substrate 1 is preferably PET (polyethylene terephthalate), etc. When the decorative molding process is insert molding, the material of the substrate 1 is preferably acrylic, an acrylic / PC (polycarbonate) composite material, PC, etc. The thickness of the substrate 1 is approximately 25 μm or more and 1000 μm or less.

[0020] For example, the image layer 2 is formed by a melt transfer method. The melt transfer method is an image formation method in which a thermal transfer sheet provided with a colorant layer containing melt ink is used, and thermal energy according to image information is applied to the thermal transfer sheet, causing the colorant layer to melt or soften due to the application of thermal energy, and then the layer is transferred onto the substrate 1 to form an image layer. The melt ink is a colorant such as a black pigment, metallic pigment, pearl pigment, or fluorescent pigment. The melt ink may also be a decorative layer containing a hologram or the like. There are no particular limitations on the thickness of the image layer 2, but an example is 0.1 μm or more and 5.0 μm or less.

[0021] The image layer 2 may be formed by transferring a receptor layer onto the substrate 1 and printing an image on the receptor layer by a sublimation transfer method. The sublimation transfer method is an image formation method in which a thermal transfer sheet provided with a colorant layer containing a sublimation dye is used, and thermal energy according to image information is applied to the thermal transfer sheet to transfer the sublimation dye contained in the colorant layer to the receptor layer, thereby forming an image. The sublimation dye may be a yellow dye, magenta dye, cyan dye, fluorescent dye, or the like.

[0022] After the image layer 2 is formed, the protective layer 3 is transferred onto the image layer 2. The protective layer 3 protects the image on the image layer 2 and can be made of a known transparent resin material. There are no particular limitations on the thickness of the protective layer 3, but an example is 0.1 μm or more and 10 μm or less.

[0023] Next, as shown in FIG. 3 (upside down from FIG. 2), the foam layer 12 is transferred from the foam layer transfer sheet 10 to a portion of the other surface of the substrate 1 (the surface opposite to the image layer 2 and protective layer 3). For example, a thermal head of a thermal transfer printer heats the foam layer transfer sheet 10 in a predetermined pattern, thereby partially transferring the foam layer 12 onto the substrate 1. The transfer pattern is not particularly limited and may be, for example, letters or a design.

[0024] The heat energy applied to the foam layer transfer sheet 10 when transferring the foam layer 12 is set to a level that does not cause the foam particles to expand.

[0025] As shown in Fig. 4, an adhesive layer 4 is formed on the other surface of the substrate 1 so as to cover the transfer layer 12, thereby obtaining a decorative sheet. The resin for the adhesive layer 4 can be a general-purpose acrylic resin, urethane resin, polyester resin, silicone resin, vinyl chloride resin, vinyl acetate resin, or a mixture or copolymer of two or more of these. There are no particular limitations on the thickness of the adhesive layer 4, but an example is 1 µm or more and 3000 µm or less.

[0026] As shown in Fig. 5, the adhesive layer 4 of the decorative sheet is bonded to the molded product 5, integrating the decorative sheet and the molded product 5. There are no particular limitations on the shape or material of the molded product 5, and it may be made of resin or metal. This decorative molding process can be performed using out-mold molding, in-mold molding, insert molding, etc., but out-mold molding is preferred, and among these, vacuum molding is preferred.

[0027] In vacuum forming, the molded product 5 is placed on a table inside the chamber box of the vacuum forming machine, and a decorative sheet is placed above the molded product 5. The chamber box is evacuated, and the decorative sheet is heated by a heater. The heated decorative sheet softens and sags under its own weight. By raising the table and placing only the area above the decorative sheet in the chamber box at atmospheric pressure, the decorative sheet adheres tightly to the molded product 5, allowing it to be molded.

[0028] The foamed particles of the foam layer 12 are expanded by heating the decorative sheet with a heater during molding, and a decorated molded product having irregularities (protrusions) in desired areas on the surface is produced as shown in FIG.

[0029] Fig. 7 shows a decorated molded product according to a comparative example. As shown in Fig. 7, in a decorative sheet in which a foam layer 12 is provided on one surface of a substrate 1 and an image layer 2 and a protective layer 3 are laminated to cover the foam layer 12, when the foam layer 12 is expanded, the image layer 2 and the protective layer 3 cannot conform to the step between the part with and without the foam layer 12 and are broken and discontinuous, resulting in a floating G.

[0030] On the other hand, in the above embodiment, the image layer 2 and the protective layer 3 are provided on the opposite side to the foam layer 12. The substrate 1, which is heated and softened during in-mold molding, can conform to the steps caused by the foamed foam layer 12. Because the image layer 2 only needs to conform to the substrate 1, the change in height is more gradual than in the comparative example shown in FIG. 7, and breakage can be suppressed. Furthermore, in the comparative example shown in FIG. 7, the image layer 2 includes an area in contact with the foam layer 12 and an area in contact with the substrate 1, and is prone to breakage at the point where the contact areas change. However, in the above embodiment, because the entire image layer 2 is in contact with the substrate 1, breakage can be suppressed even if steps are created when the foam layer 12 foams.

[0031] In the above embodiment, the foam layer 12 may be transferred multiple times. For example, as shown in Fig. 8, the foam layer 12 is transferred twice onto the substrate 1, resulting in a configuration in which two foam layers 12 are laminated. A decorative sheet having two foam layers 12 is produced, and is integrated with the molded article 5 by out-molding, and the foam layers 12 are foamed, thereby producing a decorated molded article as shown in Fig. 9.

[0032] By changing the number of times the foam layer 12 is transferred, the thickness of the foam layer 12 of the decorative sheet can be easily adjusted.

[0033] In the above embodiment, the image layer 2 and the protective layer 3 were formed on one side of the substrate 1, and then the foam layer 12 was transferred to the other side of the substrate 1. However, the order in which each layer is formed is not limited to this; for example, the image layer 2 and the protective layer 3 may be formed after the foam layer 12 is transferred.

[0034] In the above embodiment, an example has been described in which the foam layer 12 is foamed during the out-molding process, but the foam layer 12 may also be foamed by heating after the decorative sheet is adhered to the molded product 5 by out-molding.

[0035] Next, the material of the foam layer transfer sheet 10 will be described.

[0036] (base material) The substrate 11 of the foam layer transfer sheet 10 is not limited in any way, and any conventionally known material in the field of thermal transfer sheets can be appropriately selected and used. Examples include stretched or unstretched plastic films such as highly heat-resistant polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, or polyether sulfone, polypropylene, polycarbonate, cellulose acetate, polyethylene derivatives, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polymethylpentene, or ionomers. Composite films made by laminating two or more of these materials can also be used. The thickness of the substrate 11 is not particularly limited, but a thickness of 2 μm to 10 μm is preferred.

[0037] (peeling layer) A release layer can be provided on the substrate 11 to improve the transferability of the foam layer 12. Examples of binder resins constituting the release layer include thermoplastic resins exemplified by cellulose derivatives such as ethyl cellulose, nitrocellulose, and cellulose acetate; acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, and polybutyl acrylate; vinyl resins such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polyvinyl butyral; thermosetting resins exemplified by saturated or unsaturated polyester, polyurethane resin, thermosetting epoxy-amino copolymer, and thermosetting alkyd-amino copolymer (thermosetting aminoalkyd resin); silicone wax, silicone resin, silicone-modified resin, fluororesin, fluoro-modified resin, and polyvinyl alcohol.

[0038] (Foam layer) The foam layer 12 contains foam particles and a binder resin. The foam particles are heat-expandable microspheres composed of a thermoplastic resin shell and a foaming agent (core) encapsulated within the shell. The foam particles have a core-shell structure, and the microspheres as a whole exhibit heat expandability (the property of expanding the entire microsphere when heated). The thermoplastic resin is a polymer of a polymerizable component.

[0039] The polymerizable component refers to a monomer having at least one polymerizable group in its molecule, which polymerizes to form the thermoplastic resin that forms the shell of the expanded beads. Examples of polymerizable components include non-crosslinkable monomers having one reactive carbon-carbon double bond (hereinafter simply referred to as non-crosslinkable monomers) and crosslinkable monomers having two or more reactive carbon-carbon double bonds (hereinafter simply referred to as crosslinkable monomers). The crosslinkable monomers can introduce a crosslinked structure into the polymer. The reactive carbon-carbon double bond here refers to a carbon-carbon double bond that exhibits radical reactivity, and does not refer to carbon-carbon double bonds in aromatic rings such as benzene rings or naphthalene rings, but includes carbon-carbon double bonds contained in vinyl groups, (meth)acryloyl groups, allyl groups, vinylene groups, etc. Here, the (meth)acryloyl group refers to an acryloyl group or a methacryloyl group.

[0040] The blowing agent is a component that vaporizes when heated. The blowing agent is not particularly limited, but examples thereof include hydrocarbons having 3 to 13 carbon atoms such as methane, ethane, propane, (iso)butane, (iso)pentane, (iso)hexane, (iso)heptane, (iso)octane, (iso)nonane, (iso)decane, (iso)undecane, (iso)dodecane, and (iso)tridecane, hydrocarbons having more than 13 but 20 or less carbon atoms such as (iso)hexadecane and (iso)eicosane, pseudocumene, petroleum ether, normal paraffins and isoparaffins having an initial boiling point of 150°C to 260°C and / or a distillation range of 70°C to 360°C, Examples of suitable compounds include hydrocarbons such as petroleum distillates such as vinylene; halogenated hydrocarbons having 1 to 12 carbon atoms such as methyl chloride, methylene chloride, chloroform, and carbon tetrachloride; fluorine-containing compounds such as hydrofluoroether; silanes having an alkyl group having 1 to 5 carbon atoms such as tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, and trimethyl-n-propylsilane; and compounds that undergo thermal decomposition to generate gases when heated, such as azodicarbonamide, N,N'-dinitrosopentamethylenetetramine, and 4,4'-oxybis(benzenesulfonylhydrazide).

[0041] The blowing agent may be composed of one type of compound or a mixture of two or more types of compounds. The blowing agent may be linear, branched, or alicyclic, with aliphatic blowing agents being preferred.

[0042] The encapsulation rate of the blowing agent in the expanded beads is defined as the percentage of the weight of the encapsulated blowing agent relative to the weight of the expanded beads. The encapsulation rate of the blowing agent is not particularly limited, but is preferably 2% by weight or more and 50% by weight or less relative to the weight of the expanded beads.

[0043] The expansion starting temperature of the expanded beads is not particularly limited, but is preferably at least 70° C. The average particle diameter (D50) of the expanded beads is 5 μm or more and 30 μm or less.

[0044] The thickness of the foamed layer before the expanded beads is preferably 5 μm to 50 μm, more preferably 30 μm or more, and the thickness of the foamed layer after the expanded beads is preferably 50 μm to 600 μm.

[0045] The foam layer may contain an ultraviolet curable resin.

[0046] (Adhesive layer) In order to improve adhesion between the foam layer 12 and the substrate 1, which is the transfer target, an adhesive layer may be provided on the foam layer 12. Examples of materials for the adhesive layer include cellulose derivatives such as ethyl cellulose and cellulose acetate butyrate, styrene copolymers such as polystyrene and poly-α-methylstyrene, acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, and polyethyl acrylate, vinyl resins such as polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, and polyvinyl butyral, polyester, nylon resin, epoxy resin, and polyurethane.

[0047] (back layer) There are no limitations on the material of the back layer provided on the other surface of the substrate 11, and examples thereof include cellulose resins such as cellulose acetate butyrate and cellulose acetate propionate, vinyl resins such as polyvinyl butyral and polyvinyl acetal, acrylic resins such as polymethyl methacrylate, polyethyl acrylate, polyacrylamide and acrylonitrile-styrene copolymer, natural or synthetic resins such as polyamide resin, polyamideimide, polyester, polyurethane, silicone-modified or fluorine-modified urethane, etc. The back layer may contain one type of these resins alone, or two or more types.

[0048] Although the present disclosure has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0049] 1 Base material 2 Image Layer 3 protective layer 4 Adhesive layer 5 Molded products 10 Foam layer transfer sheet 12 Foam layer

Claims

1. a step of heating a foam layer transfer sheet provided with a foam layer containing foam particles, and transferring the foam layer to a predetermined region on one surface of a substrate; forming an image layer on the other side of the substrate; a step of bonding the foam layer side of the decorative sheet, in which the image layer, the base material, and the foam layer are laminated, to a molded product via an adhesive layer; foaming the foam layer; A method for manufacturing a decorated molded product comprising:

2. The method for manufacturing a decorated molded product according to claim 1 , wherein the decorative sheet and the molded product are integrated by out-molding.

3. The method for manufacturing a decorated molded product according to claim 2 , wherein the foam layer is foamed in the step of performing the out-molding.

4. The method for producing a decorated molded product according to claim 1 , further comprising transferring a protective layer onto the image layer.

5. The method for manufacturing a decorated molded product according to claim 1 , wherein the foam layer is transferred a plurality of times to laminate a plurality of the foam layers on the one surface of the substrate.

6. A substrate; a foam layer provided in a predetermined region on one surface of the substrate; an adhesive layer provided on one surface of the base material so as to cover the foam layer; an image layer provided on the other surface of the substrate; Equipped with The decorative sheet, wherein the foamed particles contained in the foamed layer are not expanded.

7. A decorative sheet as described in claim 6, wherein the foam layer is a multi-layer foam layer including at least two foam layers.

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