Method for manufacturing transfer film and transfer film

Abstract

To provide a method for manufacturing a transfer film in which a UV cured layer is not softened even when printing ink is printed a plurality of times in order to enhance design properties and which is excellent in design appearance, and to provide the transfer film.SOLUTION: A step of preparing a first film 10 having a UV-curable layer 12 containing a UV-curable compound that is cured by UV and a first peeling layer 11, a step of preparing a second film 20 having a design layer 23 and a second peeling layer 21, and a step of unwinding the second film 20, applying an adhesive agent onto the design layer 23 of the second film 20, and drying the adhesive agent. The method for manufacturing the transfer film includes a step of forming the adhesive layer 24 on the design layer 23, and a bonding step of feeding the first film 10 together with the second film 20 and bonding the first film 10 and the second film 20 to each other so that the adhesive layer 24 of the second film 20 and the UV cured layer 12 of the first film 10 are in direct contact with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a transfer film having a UV-curable layer that is cured by irradiation with UV (ultraviolet) rays, and to the transfer film. [Background technology]

[0002] Conventionally, transfer films have been known in which a release agent layer, a coating layer containing ultraviolet curable resin (UV cured layer), and an ink layer (design layer) are sequentially formed on a base film. In addition, in such transfer films, since the UV cured layer containing ultraviolet curable resin does not have solvent resistance, a technique has been known in which an aqueous polyurethane coating protective layer is interposed between the UV cured layer and the design layer to protect the UV cured layer from the organic solvent contained in the design layer (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-16353 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in order to enhance the design of transfer films, design layers are sometimes formed by printing with printing ink multiple times. However, when forming design layers by printing with printing ink multiple times, in the transfer film of Patent Document 1, some of the organic solvents used in the printing ink may permeate the aqueous polyurethane coating protective layer and soften the UV-cured layer. Furthermore, since the location where the printing ink is applied to the design layer varies depending on the design, unevenness can occur depending on the number of times the ink is applied. In particular, in Patent Document 1, an aqueous polyurethane protective coating layer and a UV cured layer are applied in that order directly on top of the design layer, which can leave unevenness on the surface of the transfer film (the surface of the UV cured layer), impairing the appearance of the design. Furthermore, in Patent Document 1, when the transfer film is transferred to an object, the aqueous polyurethane protective layer is laminated on top of the printed layer, which raises concerns that the visibility of the printed layer may be reduced.

[0005] The present invention aims to produce a high-quality transfer film that has an excellent design and appearance and in which the UV-cured layer does not soften even when printing ink multiple times to enhance the design. [Means for solving the problem]

[0006] A method for manufacturing a transfer film according to a first aspect of the present invention includes the steps of preparing a first film having a UV-cured layer containing a UV-curable compound that is cured by UV and a first peel layer, preparing a second film having a design layer and a second peel layer, unwinding the second film and applying an adhesive to the design layer of the second film and drying it to form an adhesive layer on the design layer, and unwinding the first film together with the second film and bonding the first film and the second film together so that the adhesive layer of the second film and the UV-cured layer of the first film are in direct contact. In the above-described method for producing a transfer film, the adhesive may be configured to contain an organic solvent. The above-mentioned method for producing a transfer film may be configured to include a drying step of drying the adhesive layer formed on the second film before the laminating step. In the above-mentioned method for manufacturing a transfer film, in the step of preparing the first film, the third release layer may be laminated on the opposite side of the UV cured layer from the first release layer so that the UV cured layer and the third release layer are in direct contact with each other. In the above-mentioned method for manufacturing a transfer film, in the bonding process, before bonding the first film and the second film together, the third release layer can be peeled off from the first film, and the first film and the second film can be bonded together so that the adhesive layer and the UV cured layer are in direct contact with each other. A method for manufacturing a transfer film according to a second aspect of the present invention includes the steps of preparing a first film having a first release layer, preparing a second film having a design layer and a second release layer, applying a UV curing agent containing a UV curing compound that is cured by UV onto the first release layer of the first film or onto the design layer of the second film, forming a UV cured layer by drying the UV curing agent, and bonding the second film having the design layer and second release layer onto the UV cured layer so that the design layer is in direct contact with the UV cured layer, or bonding the first film having the first release layer onto the UV cured layer so that the first release layer is in direct contact with the UV cured layer. In the above-mentioned method for manufacturing a transfer film, the process of applying the UV curing agent, the process of drying the UV curing agent, and the laminating process can be configured to be performed continuously while the first film and the second film are unwound from reels and automatically transported along a line. In the above-described method for producing a transfer film, in the step of preparing the second film, the organic solvent contained in the design layer may be evaporated by drying. The transfer film of the present invention has a first release layer, a UV-curable layer containing a UV-curable compound that is cured by UV and laminated directly or indirectly on the first release layer, an adhesive layer laminated directly on the UV-curable layer, a design layer laminated directly on the adhesive layer, and a second release layer laminated directly or indirectly on the design layer. In the transfer film, the first release layer may be thicker than the second release layer. In the transfer film, the first release layer may be thicker than the second release layer. In the transfer film, the first release layer may be made of a PET substrate coated with a release agent, and the second release layer may be made of a resin substrate not coated with a release agent. [Effects of the Invention]

[0007] According to the present invention, by pre-drying the adhesive layer that is in direct contact with the UV-cured layer, the organic solvent can be volatilized, thereby effectively preventing softening of the UV-cured layer that is in direct contact with the adhesive layer. Furthermore, in the present invention, since there is no protective layer between the design layer and the UV-cured layer, the design appearance of the design layer can be improved, and since the adhesive layer is interposed between the design layer and the UV-cured layer, the adhesive layer can absorb the unevenness of the design layer caused by the repeated application of printing ink, thereby increasing the surface flatness, so a high-quality transfer film with excellent design appearance can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating the configuration of a transfer film according to the first embodiment. [Figure 2] 3A to 3C are diagrams illustrating a method for manufacturing a transfer film according to the first embodiment. [Figure 3] 3A to 3C are diagrams illustrating a manufacturing process of the transfer film according to the first embodiment. [Figure 4] 10A and 10B are diagrams showing images of transfer films according to examples and comparative examples. [Figure 5] 10A to 10C are diagrams illustrating a method for manufacturing a transfer film according to a second embodiment. [Figure 6] 10A to 10C are diagrams illustrating a manufacturing process of a transfer film according to a second embodiment. [Figure 7] 10A to 10C are diagrams illustrating a method for manufacturing a transfer film according to a third embodiment. [Figure 8] 10A to 10C are diagrams illustrating a manufacturing process of a transfer film according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The transfer film and the method for producing the transfer film according to the present invention will be described with reference to the drawings.

[0010] First Embodiment FIG. 1 is a structural diagram of a transfer film 1 according to a first embodiment. As shown in FIG. 1, the transfer film 1 according to the first embodiment has a structure in which a first peeling layer 11, a UV cured layer 12, an adhesive layer 24, a design layer 23, an adhesive layer 22, and a second peeling layer 21 are laminated in this order. As shown in FIG. 1, the transfer film 1 according to this embodiment is formed by bonding a first film 10 having the first peeling layer 11 and the UV cured layer 12 to a second film 20 having the second peeling layer 21, the adhesive layer 22, the design layer 23, and the adhesive layer 24. Each layer constituting the transfer film 1 will be described in detail below.

[0011] [First release layer 11] The first release layer 11 is a layer that can be peeled off from the UV-cured layer 12, and can be made of a base material such as polyester (e.g., PET (polyethylene terephthalate)), polypropylene, polyethylene, or paper. To enhance peelability, these base materials can be coated with a release agent such as silicone or fluorine. The first release layer 11 according to this embodiment has a two-layer structure in which polypropylene is laminated on PET, and is not coated with a release agent. Polypropylene alone is relatively susceptible to heat and may be thermally denatured. However, using polypropylene together with PET makes it less susceptible to heat denaturation and allows for easy peeling without a release agent. Furthermore, when the first release layer 11 is made of multiple materials, it is not limited to the combination of PET and polypropylene, and the above materials can be combined as appropriate.

[0012] In this embodiment, after the UV-cured layer 12 is laminated on the first release layer 11, the UV-cured layer 12 is dried by heating at a relatively high temperature. Therefore, as described above, the substrate is preferably made of a relatively heat-resistant material such as PET, or a combination of PET and other materials. The thickness of the first release layer 11 is not particularly limited, but is preferably 15 μm or more, more preferably 25 μm or more, to prevent shrinkage or warping due to heat when the UV-cured layer 12 is dried by heating. Alternatively, the first release layer 11 may have a thickness of 40 to 60 μm. Thus, the first release layer 11 is configured to be relatively thick to protect against heat, and is preferably thicker than the second release layer 21 described below.

[0013] Furthermore, when a release agent is used in the first release layer 11, the release agent is not limited to the silicone or fluorine resins described above, and acrylic resins, melamine resins, vinyl resins, polyurethane resins, silicone resins, etc. can be used alone or in polymer blends. The first release layer 11 can be formed, for example, by diluting a raw resin with an organic solvent, applying it to the surface of a resin substrate such as PET using a roll coater, and then drying it by heating. The first release layer 11 can also be formed by gravure coating the raw resin diluted with an organic solvent onto the surface of a resin substrate.

[0014] [UV cured layer 12] The UV-cured layer 12 is a layer that hardens when exposed to ultraviolet (UV) light. After the transfer film 1 is transferred to an object and the first peelable layer 11 is peeled off, the UV-cured layer 12 hardens when exposed to UV light, protecting the underlying design layer 23 and the object. In the transfer film 1 according to this embodiment, the UV-cured layer 12 is formed by applying a coating containing a UV-curable compound (hereinafter referred to as a UV curing agent) onto the first peelable layer 11 using a method such as die coating or microgravure coating, and then drying by heating. After drying by heating, the UV-cured layer 12 is in an uncured, stretchable state, but becomes non-stretchable when exposed to UV light. The UV-cured layer 12 is in an uncured, stretchable state when shipped, distributed, or when the transfer film 1 is transferred to an object, and as a result, the transfer film 1 also has a stretchable state. The UV-cured layer 12 according to this embodiment does not have solvent resistance in an uncured state and softens when an organic solvent penetrates into it. Therefore, it is not possible to directly print a printing ink containing an organic solvent or an adhesive containing an organic solvent onto the uncured UV-cured layer 12.

[0015] The UV-curable layer 12 contains a UV-curable compound for curing by UV irradiation after transfer to the target object. The UV-curable compound is not limited as long as it is a compound that cures when irradiated with UV, and examples thereof include curable monomers and curable oligomers that polymerize when irradiated with UV. Examples of curable monomers include low-viscosity acrylic monomers, vinyl ethers, oxetane-based monomers, and cyclic aliphatic epoxy monomers. Examples of curable oligomers include acrylic oligomers. Furthermore, to improve abrasion resistance, a multifunctional monomer having three or more (meth)acryloyl groups, or an oligomer and a urethane (meth)acrylate oligomer having two or more (meth)acryloyl groups may be used. The thickness of the UV-curable layer 12 is not particularly limited, but may be 20 to 100 μm, and more preferably 30 to 70 μm.

[0016] In this embodiment, a film consisting of a first release layer 11 and a UV-cured layer 12 is referred to as a first film 10. In this embodiment, the first film 10 is produced separately from a second film 20 having a second release layer 21, an adhesive layer 22, a design layer 23, and an adhesive layer 24. The first film 10 is then bonded to the second film 20 to produce a transfer film 1. In this embodiment, the first film 10 is preferably wound into a roll, taking into consideration the storage, transportability, and ease of unwinding (handling) for bonding of the first film 10. When the first film 10 is rolled, a third release layer 13 is preferably laminated on the UV-cured layer 12, as shown in FIG. 2(A), to prevent the uncured, adhesive UV-cured layer 12 from adhering to the side of the first release layer 11 that is not coated with the release agent. In this embodiment, the first film 10 having the third release layer 13 laminated on the UV-cured layer 12 is referred to as a first film 10'. The third release layer 13 is removed immediately before the first film 10 and the second film 20 are bonded together. Alternatively, instead of including the third release layer 13, a release agent may be applied to both sides of the first release layer 11. In this case, when the first film 10 is rolled as described above, it is possible to prevent the UV-cured layer 12 from adhering to the side of the first release layer 11 that is not coated with the release agent. Furthermore, when the first film 10 is not rolled, the third release layer 13 can be omitted. The third release layer 13 can be made of, for example, CPP (non-oriented polypropylene) or an olefin-based resin.

[0017] [Second release layer 21] The second release layer 21 is a release layer on the second film 20 side having the design layer 23, and can be configured with a substrate such as polyester, polypropylene, polyethylene, or paper. These substrates can also be coated with a release agent such as silicone or fluorine. The adhesive layer 22 laminated on the second release layer 21 can be dried by heating at a relatively low temperature compared to the UV-cured layer 12. Therefore, the second release layer 21 can be made of an inexpensive material, such as polypropylene, which is relatively heat-sensitive. Furthermore, because the second release layer 21 can be dried by heating at a relatively low temperature, it is less likely to warp due to heat. Therefore, the thickness of the second release layer 21 can be made thinner than the thickness of the first release layer 11. Furthermore, when the second release layer 21 is made of polypropylene, its low polarity makes it easy to peel from the adhesive layer 22, and therefore it can be configured without coating with a release agent. In particular, in this embodiment, as will be described later, an adhesive is applied onto second release layer 21 to form adhesive layer 22, and therefore, when a release agent is coated, the release agent of second release layer 21 may transfer to adhesive layer 22. Therefore, by configuring second release layer 21 not to be coated with a release agent, it is possible to prevent the release agent from penetrating into adhesive layer 22. The thickness of second release layer 21 is not particularly limited, but may be 10 to 100 μm, preferably 20 to 80 μm, and more preferably 30 to 50 μm.

[0018] [Adhesive layer 22] The adhesive layer 22 is a layer that is exposed when the second release layer 21 is peeled off, and is a layer that adheres the transfer film 1 to an object when transferring the transfer film 1 to the object. The adhesive layer 22 is a layer formed by applying an adhesive onto the second release layer 21, and materials known in the art for transfer films, such as thermoplastic acrylic adhesives, epoxy adhesives, and hot melt adhesives, can be used for the adhesive layer 22. The thickness of the adhesive layer 22 is not particularly limited, but can be 2 to 10 μm, and is more preferably 5 to 8 μm.

[0019] [Design Layer 23] The design layer 23 is a layer onto which a design is applied by printing, and provides the design appearance of the object to which the transfer film 1 is transferred. The thickness of the design layer 23 varies depending on the type of decoration, but is generally preferably about 0.1 to 20 μm, and more preferably about 1 to 10 μm. In this embodiment, the design layer 23 is formed by applying printing ink onto the adhesive layer 22 by gravure printing or the like. Furthermore, when forming the design layer 23, printing inks of various colors can be printed multiple times to form a three-dimensional design layer 23 with excellent design.

[0020] Examples of decorations include wood grain, stone grain, sand grain, tiled, brickwork, fabric, leather, geometric shapes, letters, symbols, abstract patterns, and floral patterns, and can be selected according to the purpose. Printing methods include inkjet printing, gravure printing, flexographic printing, silkscreen printing, and offset printing. The printing conditions are not particularly limited, and printing can be performed at a line speed of 50 to 200 m / min and a drying temperature of 40 to 150°C. Printing inks that contain colorants, binder resins, and solvents can be used. These inks may be publicly known or commercially available, but it is preferable to use paper printing inks such as urethane-based inks or cellulose-based inks.

[0021] The colorant for the design layer 23 is not particularly limited, and known inorganic or organic pigments can be used. Examples of inorganic pigments include titanium oxide, zinc oxide, carbon black, black iron oxide, yellow iron oxide, chrome yellow, molybdate orange, cadmium yellow, nickel titanium yellow, chrome titanium yellow, iron oxide (red iron oxide), cadmium red, ultramarine, Prussian blue, cobalt blue, chromium oxide, cobalt green, aluminum powder, bronze powder, mica titanium, and zinc sulfide. Examples of organic pigments include aniline black, perylene black, azo pigments (azo lakes, insoluble azo pigments, condensed azo pigments), polycyclic pigments (isoindolinone, isoindoline, quinophthalone, perinone, flavanthrone, anthrapyrimidine, anthraquinone, quinacridone, perylene, diketopyrrolopyrrole, dibromoanzanthrone, dioxazine, thioindigo, phthalocyanine, indanthrone, and halogenated phthalocyanine pigments). The content of the pigment is preferably about 10 to 100 parts by mass, and more preferably about 15 to 50 parts by mass, per 100 parts by mass of the resin component.

[0022] In addition, in the design layer 23, the binder resin is not particularly limited, and examples thereof include acrylic resins, styrene resins, polyester resins, urethane resins, chlorinated polyolefin resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins, alkyd resins, petroleum resins, ketone resins, epoxy resins, melamine resins, fluorine resins, silicone resins, cellulose derivatives, rubber resins, etc. Examples of solvents (or dispersion media) include petroleum-based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ester-based organic solvents such as ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and 2-ethoxyethyl acetate; alcohol-based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, and propylene glycol; ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based organic solvents such as diethyl ether, dioxane, and tetrahydrofuran; chlorine-based organic solvents such as dichloromethane, carbon tetrachloride, trichloroethylene, and tetrachloroethylene; and water. These solvents (or dispersion media) can be used alone or in the form of a mixture.

[0023] The design layer 23 can also be configured to include metal flakes or metal foil, such as silver. For example, a configuration including metal foil can be achieved by forming a foil film by vapor-depositing metal onto the underside of a base film, pressing the foil film onto the top surface of the design layer 23, and then peeling off the base film and attaching only the foil layer. Common metals used for the metal frame and foil layer include pure gold, pure silver, copper, tin, and aluminum. However, red silver foil and blue silver foil, which are obtained by smoking silver to change the color tone, and brass that is colored yellow to resemble gold, can also be used. Furthermore, the design layer 23 can be made even more expressive by using holographic foil, which creates interference fringes in the foil by adding an embossing process to the metal foil manufacturing process, thereby creating a three-dimensional pattern.

[0024] [Adhesive layer 24] The adhesive layer 24 is an adhesive layer for bonding the second film 20 to the first film 10. The adhesive layer 24 is formed by applying an adhesive to the design layer 23. The adhesive of the adhesive layer 24 is not particularly limited as long as it dries easily and spreads easily at room temperature. However, it preferably contains an organic solvent to enhance drying properties. By applying an adhesive containing an organic solvent and then heating and drying the adhesive layer 24, the adhesive layer 24 is formed as a layer that does not contain organic solvent or contains a trace amount of organic solvent. The organic solvent content of the adhesive layer 24 after heating and drying may be any amount that does not penetrate the UV-cured layer 12. For example, while the adhesive layer 24 before drying contains 30% or more of organic solvent, the organic solvent content after drying may be 10% or less, preferably 5% or less, and more preferably 1% or less. The adhesive of the adhesive layer 24 may also be a solventless adhesive or a thermoplastic adhesive resin that does not contain organic solvent. The thickness of the adhesive layer 24 is not particularly limited, but can be set to 5 to 20 μm, and more preferably to 7 to 15 μm.

[0025] [Transfer of transfer film 1] The transfer film 1 according to this embodiment can be transferred to an object by peeling off the second release layer 21 and attaching the transfer film 1 to the object, thereby transferring the transfer film 1 including the design layer 23 to the object. In particular, in the transfer film 1 according to this embodiment, the UV-cured layer 12 is stretchable in an uncured state, and the transfer film 1 as a whole is also stretchable. Therefore, the transfer film 1 can be suitably transferred to an object that has unevenness or curvature, or even a rounded object.

[0026] After transferring the transfer film 1 to the target object, the first release layer 11 is peeled off to expose the uncured UV-cured layer 12. The exposed UV-cured layer 12 can then be irradiated with UV light to cure the UV-cured layer 12. The transfer film 1 according to this embodiment can be transferred without hydraulic transfer or other processes, and it is burr-free, eliminating the need for trimming and facilitating alignment. Furthermore, the transfer film 1 according to this embodiment can decorate an object simply by transferring the transfer film 1 to the object and irradiating it with UV light. This eliminates the need for a paint booth, simplifying the decoration process and equipment compared to painting decoration. Furthermore, it also reduces carbon dioxide emissions, making it superior from a carbon-neutral perspective. Furthermore, because the transfer film 1 according to this embodiment does not include a resin protective layer such as polyurethane, the design layer 23 is easily visible and offers excellent designability.

[0027] [Manufacturing method] Next, a method for manufacturing the transfer film 1 according to this embodiment will be described with reference to Figures 2 and 3. Figure 2 is a diagram for explaining the manufacturing process of the transfer film 1 according to this embodiment. Also, Figure 3 is a diagram for explaining the manufacturing process of the transfer film 1 according to this embodiment. In this embodiment, first, as shown in Figure 2(A), a first film 10' having a first release layer 11, a UV cured layer 12, and a third release layer 13, and as shown in Figure 2(B), a second film 20' having a second release layer 21, an adhesive layer 22, and a design layer 23 are prepared.

[0028] Specifically, the first film 10' is pre-manufactured as a three-layer structure as shown in FIG. 2(A) by applying a UV curing agent to the first release layer 11, heating and drying the layer to form a UV-cured layer 12, and then laminating a third release layer 13 thereon. The heating conditions for forming the UV-cured layer 12 are not particularly limited, but may be, for example, a heating time of 1 to 5 minutes, preferably 2 to 3 minutes, and a heating temperature of 80 to 140°C, preferably 110 to 130°C. In this embodiment, the manufactured first film 10' is stored in a rolled state, and when the transfer film 1 is manufactured using the first film 10', the rolled state is attached to the first payout reel 101 as shown in FIG. 2(B) by repeatedly applying and drying printing ink by gravure printing or the like onto the adhesive layer 22 to form the design layer 23. The manufactured second film 20' is also stored in a rolled state, and when the transfer film 1 is manufactured using the second film 20', it is attached to the second supply reel 102 in its rolled state, as shown in FIG.

[0029] As shown in FIG. 3 , the second film 20′ unwound from the second supply reel 102 is passed through an adhesive application section 104, where an adhesive is applied to the design layer 23 of the second film 20′ by an adhesive application roller 105. The adhesive is then heated and dried in a drying device 106, resulting in the formation of a second film 20 having an adhesive layer 24 laminated on the design layer 23, as shown in FIG. 2(D). The heating conditions for forming the adhesive layer 24 are not particularly limited, but may be, for example, a heating time of 5 minutes or less, preferably 1 to 2 minutes, and a heating temperature of 80 to 140°C, preferably 110 to 130°C. The third release layer 13 is then peeled off from the first film 10′ unwound from the first supply reel 101 by a peeling device 107, resulting in the first film 10 having the UV-cured layer 12 exposed, as shown in FIG. 2(C). Then, the first film 10 and the second film 20 are pressed and bonded together by a bonding device 108 such as a pressure roller so that the adhesive layer 24 of the second film 20 and the UV cured layer 12 of the first film 10 come into direct contact with each other, thereby forming the transfer film 1 as shown in Fig. 2(E). After bonding, the transfer film 1 is taken up by a recovery reel 103 and held in a roll.

[0030] In this embodiment, the first film 10' and the second film 20' are unwound at approximately the same speed from the first unwinding reel 101 and the second unwinding reel 102 and bonded together. In the manufacturing method of the transfer film 1 according to this embodiment, an adhesive containing an organic solvent is applied to the design layer 23 of the second film 20' to form the adhesive layer 24, but by heating and drying the adhesive after application, the organic solvent volatilizes and disappears in the dried adhesive layer 24, or remains only in trace amounts, effectively preventing the UV-cured layer 12 from being softened by the organic solvent even when the first film 10 and the second film are bonded together.

[0031] Furthermore, multiple types of second film 20' can be prepared for each design of design layer 23, and by placing second film 20' with the design to be manufactured on second payout reel 102, transfer film 1 with various designs can be manufactured in small lots with a wide variety of designs. In particular, in this embodiment, first film 10' can be used in common regardless of design, eliminating the need to prepare first film 10' for each design. [Example]

[0032] In this example, transfer film 1 according to the present invention and a transfer film according to a comparative example were produced, and the state of each transfer film was observed. Figure 4 shows images of each transfer film rolled into a film and then pulled out from the film roll, with (A) showing transfer film 1 according to the present invention and (B) showing the transfer film of the comparative example. Specifically, the transfer film 1 shown in Figure 4(A) of the embodiment was produced by preparing a first film 10' having a first peeling layer 11, a UV cured layer 12, and a third peeling layer 13, as shown in Figure 3, and a second film 20' having a second peeling layer 21, an adhesive layer 22, and a design layer 23, applying an adhesive to the design layer 23 of the second film 20', heating and drying the adhesive at 120°C for 2 minutes to form an adhesive layer 24, peeling the third peeling layer 13 from the first film 10', and then pressing and bonding the first film 10 and the second film 20 together so that the adhesive layer 24 of the second film 20 and the UV cured layer 12 of the first film 10 are in direct contact. The first film 10' was formed by applying a UV curing agent to the first release layer 11, heating and drying it at 120°C for 2 minutes to form the UV-cured layer 12, and then laminating the third release layer 13. The second film 20' was formed by applying an adhesive to the second release layer 21 and heating and drying it to form the adhesive layer 22, and then repeatedly applying and drying a printing ink containing an organic solvent by gravure printing on the adhesive layer 22 to form the design layer 23. On the other hand, the transfer film of the comparative example shown in (B) was created by laminating the first release layer 11, the UV-cured layer 12, the design layer 23, the adhesive layer 22, and the second release layer 21 in that order. The transfer film of the comparative example shown in (B) had the same composition of each layer as the transfer film of the example shown in (A). The UV-cured layer 12 of the comparative example was formed by applying a UV curing agent onto the first peel layer 11 and then heating and drying it at 120°C for 2 minutes, similar to the UV-cured layer 12 of the example. The design layer 23 of the comparative example was formed in the same manner as the example, except that it was directly laminated on top of the UV-cured layer 12.

[0033] As shown in FIG. 4(A), the transfer film 1 according to the embodiment could be pulled out cleanly from the film roll. Furthermore, visual inspection of the transfer film 1 according to the embodiment revealed no visible irregularities due to overlapping prints on the design layer 23, and the design appearance was excellent. On the other hand, as shown in FIG. 4(B), the transfer film according to the comparative example peeled off in the thickness direction (between the design layer 23 and the UV cured layer 12, for example) due to the influence of the organic solvent contained in the design layer 23, resulting in one transfer film being blocked by the other. Furthermore, the transfer film according to the comparative example also showed a deterioration in the design appearance due to the irregularities caused by overlapping prints on the design layer 23.

[0034] As described above, the manufacturing method of the transfer film 1 according to this embodiment includes the steps of preparing a first film 10 having a UV-cured layer 12 containing a UV-curable compound that is cured by UV, and a first peel layer 11; preparing a second film 20 having a design layer 23 and a second peel layer 21; applying an adhesive onto the design layer 23 and drying it to produce the second film 20 having an adhesive layer 24 formed on the design layer 23; and a bonding step of bonding the first film 10 and the second film 20 together so that the adhesive layer 24 and the UV-cured layer 12 are in direct contact. As a result, in the transfer film 1 according to this embodiment, after spreading an adhesive containing an organic solvent on the design layer 23, the organic solvent is volatilized by heating and drying to form an adhesive layer 24 that does not contain any organic solvent or that contains only a trace amount of organic solvent, and even if the adhesive layer 24 of the second film 20 and the UV-cured layer 12 of the first film are brought into direct contact with each other, the UV-cured layer 12 can be prevented from softening due to the organic solvent contained in the adhesive layer 24. As a result, the transfer film 1 can be manufactured by directly bonding the adhesive layer 24 of the second film 20 and the UV-cured layer 12 of the first film, and therefore the transfer film 1 having the design layer 23 and the UV-cured layer 12 can be manufactured without providing a protective layer using a polyurethane resin or the like.

[0035] Furthermore, in the transfer film 1 according to this embodiment, the UV-cured layer 12 is manufactured using the first film 10 separately from the design layer 23, effectively preventing unevenness in the UV-cured layer 12 due to the unevenness of the design layer 23. That is, the design layer 23 may be printed with multiple layers of printing ink to create a three-dimensional design, and unevenness may occur on the surface of the design layer 23 due to overlapping printing inks. In such cases, if the coating material constituting the UV-cured layer 12 is applied to the design layer 23 to form the UV-cured layer 12, unevenness may also occur in the UV-cured layer 12 due to the unevenness of the design layer 23, resulting in perceptible unevenness or distortion in appearance. In contrast, in the transfer film 1 according to this embodiment, the UV-cured layer 12 is formed on the first release layer 11 during the manufacturing process of the first film 10, allowing the surface of the UV-cured layer 12, which becomes the surface of the transfer film 1 after transfer, to be flat. In the transfer film 1 according to this embodiment, the unevenness of the design layer 23 is offset by the deformation of the adhesive layer 24 when the first film 10 and the second film 20 are pressure-bonded together.

[0036] Furthermore, in the manufacturing method of the transfer film 1 according to this embodiment, the first film 10 and the second film 20 are manufactured separately, thereby improving yield. That is, if the six layers of the transfer film 1 according to this embodiment are stacked in order, if any one layer is defective, all of the layers must be discarded. However, if the first film 10 and the second film 20 are separated, even if one film is defective, the other film does not need to be discarded. Furthermore, in the manufacturing method of the transfer film 1 according to this embodiment, while the second film 20 must be manufactured for each design of the design layer 23, the first film 10 can be used in common, and therefore, by replacing the second film 20, transfer films 1 with the required number of designs can be manufactured in small batches.

[0037] In addition, in the transfer film 1 of this embodiment, by making the thickness of the first peeling layer 11 thicker than that of the second peeling layer 21, even when a UV-cured layer 12, which is heated and dried at a relatively high temperature compared to the adhesive layer 22, is formed on the first peeling layer 11, the first peeling layer 11 can be effectively prevented from shrinking or warping due to heat.

[0038] Furthermore, the manufacturing method of the transfer film 1 according to the first embodiment is suitable for manufacturing a wide variety of small lots of transfer films 1. That is, because the UV curing agent used to form the UV cured layer 12 is expensive, it is desirable to manufacture a large area at once to reduce costs. However, in the manufacturing method of the transfer film 1 according to the first embodiment, even if the first film 10 having the UV cured layer 12 is manufactured over a large area, the first film 10 can be cut and used when bonding the first film 10 to the second film 20, so manufacturing costs can be reduced even when manufacturing the transfer film 1 in a wide variety of small lots.

[0039] Second Embodiment Next, a second embodiment of the present invention will be described. Fig. 5 is a diagram illustrating a method for manufacturing a transfer film 1' according to the second embodiment, and Fig. 6 is a diagram illustrating the manufacturing process of the transfer film 1' according to the second embodiment. As shown in Fig. 5(D), the transfer film 1' according to the second embodiment has a structure in which a first release layer 11, a UV cured layer 12, a design layer 23, an adhesive layer 22, and a second release layer 21 are laminated in this order.

[0040] In the second embodiment, similarly to the first embodiment, a second film 20' is prepared as shown in Fig. 5(B). Also, in the second embodiment, a first release layer 11 without a UV cured layer 12 is prepared instead of a first film 10 as shown in Fig. 5(A). Then, as shown in Fig. 6, the second film 20' is set on a second supply reel 102, and the first release layer 11 is set on a first supply reel 101.

[0041] As shown in FIG. 6 , when the second film 20′ is unwound from the second supply reel 102, a UV curing agent is applied to the design layer 23 of the second film 20′ by an application device 109, and the applied UV curing agent is heated and dried by a drying device 106 to form the UV-cured layer 12. In the second embodiment, since the organic solvent contained in the design layer 23 of the second film 20′ is evaporated by drying during the preparation of the second film 20′, even if the UV-cured layer 12 is directly laminated on the design layer 23, the UV-cured layer 12 is prevented from being softened by the organic solvent. Furthermore, in the second embodiment, the UV-cured layer 12 is formed on the design layer 23 by applying a UV-curing agent to the heated and dried design layer 23, and then heating and drying the applied UV-curing agent to harden it. Therefore, there is no need to interpose an adhesive between the UV-cured layer 12 and the design layer 23. In the following description, the film in which the UV cured layer 12 is formed on the second film 20′ will be referred to as a third film 30.

[0042] Next, the first release layer 11, which is unwound from the first supply reel 101, is bonded onto the third film 30. In the second embodiment, the first release layer 11 is directly bonded to the UV cured layer 12 of the third film 30 without using an adhesive, thereby producing a transfer film 1′ in which the first release layer 11, the UV cured layer 12, the design layer 23, the adhesive layer 22, and the second release layer 21 are laminated in this order.

[0043] As described above, in the manufacturing method of the transfer film 1' according to the second embodiment, the design layer 23 is not laminated on the UV cured layer 12, but the UV cured layer 12 is formed on the design layer 23 from which the organic solvent has been evaporated in advance, thereby effectively preventing the UV cured layer 12 from being softened by the organic solvent contained in the design layer 23. Furthermore, compared to the manufacturing method of the transfer film 1 according to the first embodiment, the transfer film 1' according to the second embodiment does not require the step of peeling off the third release layer 13 of the first film 10, thereby simplifying the manufacturing process.

[0044] Third Embodiment Next, a third embodiment of the present invention will be described. Fig. 7 is a diagram illustrating a method for manufacturing a transfer film 1' according to the third embodiment, and Fig. 8 is a diagram illustrating a method for manufacturing a transfer film 1' according to the third embodiment. The transfer film 1' according to the third embodiment has the same configuration as the transfer film 1' of the second embodiment, that is, as shown in Fig. 7(D), it has a structure in which a first release layer 11, a UV cured layer 12, a design layer 23, an adhesive layer 22, and a second release layer 21 are laminated in this order.

[0045] In the third embodiment, as in the second embodiment, a first peeling layer 11 (see FIG. 7(A)) on which a UV cured layer 12 is not formed and a second film 20′ (see FIG. 7(B)) are prepared in advance. In the third embodiment, as shown in FIG. 8, the second film 20′ is set on the second supply reel 102, and the first peeling layer 11 is set on the first supply reel 101.

[0046] As shown in FIG. 8 , when the first peeling layer 11 is unwound from the first supply reel 101, a coating device 109 applies a UV curing agent onto the first peeling layer 11, and a drying device 106 heats and dries the applied UV curing agent, thereby forming a UV cured layer 12 on the first peeling layer 11, thereby forming the first film 10. Then, a second film 20′ unwound from a second supply reel 102 is bonded to the first film 10 on which the UV cured layer 12 has been formed. In the third embodiment, as in the second embodiment, the UV cured layer 12 of the first film 10 is directly bonded to the design layer of the second film 20′ without using an adhesive, thereby producing a transfer film 1′ in which the first peeling layer 11, the UV cured layer 12, the design layer 23, the adhesive layer 22, and the second peeling layer 21 are laminated in this order.

[0047] In the third embodiment, as in the second embodiment, when the second film 20' is prepared in advance, the organic solvent contained in the design layer 23 of the second film 20' is evaporated by heating and drying, so even if the design layer 23 and the UV cured layer 12 are bonded together so that they are in direct contact with each other, the UV cured layer 12 can be prevented from softening.

[0048] Thus, in the manufacturing method of the transfer film 1′ according to the third embodiment, as in the first and second embodiments, instead of laminating the design layer 23 on the UV cured layer 12, the UV cured layer 12 is formed on the first peel layer 11, and then the first film 10 and the second film 20 are bonded together so that the design layer 23, from which the organic solvent has been evaporated, is in direct contact with the UV cured layer 12, thereby effectively preventing the UV cured layer 12 from being softened by the organic solvent contained in the design layer 23. Furthermore, as in the second embodiment, the transfer film 1′ according to the third embodiment does not require the step of peeling off the third peel layer 13 of the first film 10, compared to the manufacturing method of the transfer film 1 according to the first embodiment, thereby simplifying the manufacturing process. In addition, in the third embodiment, a UV curing agent is applied onto the first peel-off layer 11, and then the applied UV curing agent is heated and dried to harden it to a state with a certain degree of viscosity, and in that state, it is bonded to the design layer 23 so that it is in contact with the design layer 23, thereby eliminating the need to interpose an adhesive between the UV curing layer 12 and the design layer 23.

[0049] Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments. Various modifications and improvements can be made to the above-described embodiments, and such modifications and improvements are also included in the technical scope of the present invention. [Explanation of symbols]

[0050] 1,1'...Transfer film 10,10'...First film 11...First release layer 12…UV hardening layer 13...Third release layer 20,20'...2nd film 21...Second release layer 22...adhesive layer 23...Design layer 24...adhesive layer 30...3rd film 101...First reel 102...Second reel 103...Recovery reel 104...adhesive application section 105...Adhesive application roller 106...Drying equipment 107... Peeling device 108... Bonding device 109... Coating device

Claims

1. Providing a first film having a UV curable layer including a UV curable compound that is cured by UV and a first release layer; providing a second film having a design layer and a second release layer; a step of unwinding the second film, applying an adhesive agent onto the design layer of the second film, and drying the applied adhesive agent to form an adhesive layer on the design layer; a bonding process for unwinding the first film together with the second film and bonding the first film and the second film together so that the adhesive layer of the second film and the UV cured layer of the first film are in direct contact with each other.

2. The method for producing a transfer film according to claim 1 , wherein the adhesive contains an organic solvent.

3. The method for producing a transfer film according to claim 1 , further comprising a step of drying the adhesive layer formed on the second film before the bonding step.

4. 2. The method for manufacturing a transfer film according to claim 1, wherein in the step of preparing the first film, the third release layer is laminated on the opposite side of the UV cured layer from the first release layer so that the UV cured layer and the third release layer are in direct contact with each other.

5. 5. The method for manufacturing a transfer film according to claim 4, wherein in the bonding process, before bonding the first film and the second film, the third release layer is peeled off from the first film, and the first film and the second film are bonded together so that the adhesive layer and the UV cured layer are in direct contact with each other.

6. providing a first film having a first release layer; providing a second film having a design layer and a second release layer; A step of applying a UV curing agent containing a UV curing compound that is cured by UV onto the first release layer of the first film or onto the design layer of the second film; drying the UV curing agent to form a UV cured layer; A method for manufacturing a transfer film, comprising a bonding step of bonding the second film having the design layer and a second release layer onto the UV cured layer so that the design layer is in direct contact with the second film, or bonding the first film having the first release layer onto the UV cured layer so that the first release layer is in direct contact with the second film.

7. 7. The method for manufacturing a transfer film according to claim 6, wherein the step of applying the UV curing agent, the step of drying the UV curing agent, and the step of laminating are carried out continuously while the first film and the second film are unwound from reels and the line is automatically transported.

8. The method for producing a transfer film according to claim 6 , wherein in the step of preparing the second film, the organic solvent contained in the design layer is evaporated by drying.

9. a first release layer; and a UV curing layer directly or indirectly laminated on the first release layer, the UV curing layer including a UV curing compound that is cured by UV; an adhesive layer laminated directly on the UV curable layer; A design layer laminated directly on the adhesive layer; A transfer film having a second release layer laminated directly or indirectly on the design layer.

10. The transfer film according to claim 9, wherein the adhesive layer is a layer formed by applying an adhesive containing an organic solvent and then drying the adhesive to volatilize the organic solvent.

11. The transfer film according to claim 9 , wherein the first release layer is thicker than the second release layer.

12. the first release layer is made of a PET substrate coated with a release agent; The transfer film according to claim 9 , wherein the second release layer is made of a resin substrate to which no release agent is applied.

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